REVIEW | doi:10.20944/preprints202004.0203.v4
Online: 2 November 2020 (10:18:00 CET)
The science around the use of masks by the general public to impede COVID-19 transmission is advancing rapidly. Policymakers need guidance on how masks should be used by the general population to combat the COVID-19 pandemic. In this narrative review, we develop an analytical framework to examine mask usage, considering and synthesizing the relevant literature to inform multiple areas: population impact; transmission characteristics; source control; PPE; sociological considerations; and implementation considerations. A primary route of transmission of COVID-19 is via respiratory droplets, and is known to be transmissible from presymptomatic and asymptomatic individuals. Reducing disease spread requires two things: first, limit contacts of infected individuals via physical distancing and other measures, and second, reduce the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. The decreased transmissibility could substantially reduce the death toll and economic impact while the cost of the intervention is low. Given the current shortages of medical masks we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory droplets become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask-wearing by infectious people ("source control") with benefits at the population-level, rather than mask-wearing by susceptible people, such as health-care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
ARTICLE | doi:10.20944/preprints202003.0226.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: COVID-2019; Mpro; 6LU7; medicinal plant compounds; docking
Online: 13 March 2020 (03:19:02 CET)
COVID-19, a new strain of coronavirus (CoV), was identified in Wuhan, China, in 2019. No specific therapies are available and investigations regarding COVID-19 treatment are lacking. Liu et al. (2020) successfully crystallised the COVID-19 main protease (Mpro), which is a potential drug target. The present study aimed to assess bioactive compounds found in medicinal plants as potential COVID-19 Mpro inhibitors, using a molecular docking study. Molecular docking was performed using Autodock 4.2, with the Lamarckian Genetic Algorithm, to analyse the probability of docking. COVID-19 Mpro was docked with several compounds, and docking was analysed by Autodock 4.2, Pymol version 220.127.116.11 Edu, and Biovia Discovery Studio 4.5. Nelfinavir and lopinavir were used as standards for comparison. The binding energies obtained from the docking of 6LU7 with native ligand, nelfinavir, lopinavir, kaempferol, quercetin, luteolin-7-glucoside, demethoxycurcumin, naringenin, apigenin-7-glucoside, oleuropein, curcumin, catechin, epicatechin-gallate, zingerol, gingerol, and allicin were -8.37, -10.72, -9.41, -8.58, -8.47, -8.17, -7.99, -7.89, -7.83, -7.31, -7.05, -7.24, -6.67, -5.40, -5.38, and -4.03 kcal/mol, respectively. Therefore, nelfinavir and lopinavir may represent potential treatment options, and kaempferol, quercetin, luteolin-7-glucoside, demethoxycurcumin, naringenin, apigenin-7-glucoside, oleuropein, curcumin, catechin, and epicatechin-gallate appeared to have the best potential to act as COVID-19 Mpro inhibitors. However, further research is necessary to investigate their potential medicinal use.
ARTICLE | doi:10.20944/preprints202007.0025.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: SARS-CoV-2; COVID-19; outpatients; treatment; zinc; hydroxychloroquine; azithromycin
Online: 3 July 2020 (08:52:22 CEST)
Objective: To describe outcomes of patients with coronavirus disease 2019 (COVID-19) in the outpatient setting after early treatment with zinc, low dose hydroxychloroquine, and azithromycin (the triple therapy) dependent on risk stratification. Design: Retrospective case series study. Setting: General practice. Participants: 141 COVID-19 patients with laboratory confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in the year 2020. Main Outcome Measures: Risk-stratified treatment decision, rate of hospitalization and all-cause death. Results: Of 335 positively PCR-tested COVID-19 patients, 127 were treated with the triple therapy. 104 of 127 met the defined risk stratification criteria and were included in the analysis. In addition, 37 treated and eligible patients who were confirmed by IgG tests were included in the treatment group (total N=141). 208 of the 335 patients did not meet the risk stratification criteria and were not treated. After 4 days (median, IQR 3-6, available for N=66/141) of onset of symptoms, 141 patients (median age 58 years, IQR 40-67; 73% male) got a prescription for the triple therapy for 5 days. Independent public reference data from 377 confirmed COVID-19 patients of the same community were used as untreated control. 4 of 141 treated patients (2.8%) were hospitalized, which was significantly less (p<0.001) compared with 58 of 377 untreated patients (15.4%) (odds ratio 0.16, 95% CI 0.06-0.5). Therefore, the odds of hospitalization of treated patients were 84% less than in the untreated group. One patient (0.7%) died in the treatment group versus 13 patients (3.5%) in the untreated group (odds ratio 0.2, 95% CI 0.03-1.5; p=0.16). There were no cardiac side effects. Conclusions: Risk stratification-based treatment of COVID-19 outpatients as early as possible after symptom onset with the used triple therapy, including the combination of zinc with low dose hydroxychloroquine, was associated with significantly less hospitalizations and 5 times less all-cause deaths.
ARTICLE | doi:10.20944/preprints202004.0315.v1
Subject: Life Sciences, Molecular Biology Keywords: COVID-19; SARS-CoV2; ACE2 receptor; medical cannabis; CBD
Online: 19 April 2020 (02:45:50 CEST)
With the rapidly growing pandemic of COVID-19 caused by the new and challenging to treat zoonotic SARS-CoV2 coronavirus, there is an urgent need for new therapies and prevention strategies that can help curtail disease spread and reduce mortality. Inhibition of viral entry and thereby spread constitute plausible therapeutic avenues. Similar to other respiratory pathogens, SARS-CoV2 is transmitted through respiratory droplets, with potential for aerosol and contact spread. It uses receptor-mediated entry into the human host via angiotensin-converting enzyme II (ACE2) that is expressed in lung tissue, as well as oral and nasal mucosa, kidney, testes, and the gastrointestinal tract. Modulation of ACE2 levels in these gateway tissues may prove a plausible strategy for decreasing disease susceptibility. Cannabis sativa, especially one high in the anti-inflammatory cannabinoid cannabidiol (CBD), has been proposed to modulate gene expression and inflammation and harbour anti-cancer and anti-inflammatory properties. Working under the Health Canada research license, we have developed over 800 new Cannabis sativa lines and extracts and hypothesized that high-CBD C. sativa extracts may be used to modulate ACE2 expression in COVID-19 target tissues. Screening C. sativa extracts using artificial human 3D models of oral, airway, and intestinal tissues, we identified 13 high CBD C. sativa extracts that modulate ACE2 gene expression and ACE2 protein levels. Our initial data suggest that some C. sativa extract down-regulate serine protease TMPRSS2, another critical protein required for SARS-CoV2 entry into host cells. While our most effective extracts require further large-scale validation, our study is crucial for the future analysis of the effects of medical cannabis on COVID-19. The extracts of our most successful and novel high CBD C. sativa lines, pending further investigation, may become a useful and safe addition to the treatment of COVID-19 as an adjunct therapy. They can be used to develop easy-to-use preventative treatments in the form of mouthwash and throat gargle products for both clinical and at-home use. Such products ought to be tested for their potential to decrease viral entry via the oral mucosa. Given the current dire and rapidly evolving epidemiological situation, every possible therapeutic opportunity and avenue must be considered.
REVIEW | doi:10.20944/preprints201808.0433.v1
Subject: Engineering, General Engineering Keywords: fermentation; bioreactor; heat transfer; mass transfer
Online: 24 August 2018 (11:34:14 CEST)
Fermenter is a vessel that maintains optimum environment for the development of significant microorganism used in large scale fermentation process and the commercial production of products like Alcoholic beverages, Enzymes, Antibiotics, Organic acids etc. The fermenter aims to produce biological product like vaccines and hormones, it is necessary to monitor and control the different parameters like external and internal mass transfer, heat transfer, fluid velocity, shear stress, agitation speed, aeration rate, cooling rate or heating intensity, and the feeding rate, nutrients, base or acid valve. Fermentation in the fermenter are accomplished in several configuration and these simple configurations are batch, fed-batch and continuous fermentation process. Fermentation process is carried out in small or large size fermenter depending on product quantity. The selection of the suitable process depends on the fermentation kinetics, type of microorganism used and process economic aspects. Improved modelling tools, reactor operation and reactor design in bioreactor is because of mass transfer behavior and it is important for reaction rate maximizing, throughput rates optimization and cost minimizing. The fermenter design, fermentation process, types of the fermenter that are used in industries and heat and mass transfer in fermenter is discussed.
ARTICLE | doi:10.20944/preprints202101.0412.v2
Subject: Keywords: laser for mosquito control; deep learning for mosquito control; insect detection; mosquito neutralization; pest detection; insect recognition; Raspberry Pi3; Raspberry Pi4; OpenCV for small object detect
Online: 2 August 2021 (16:44:07 CEST)
More than 700 thousand human deaths from mosquito bites are observed annually in the world. It is more than 2 times the number of annual murders in the world. In this regard, the invention of new more effective methods of protection against mosquitoes is necessary. In this article for the first time, comprehensive studies of mosquito neutralization using machine vision and a 1 W power laser are considered. Developed laser installation with Raspberry Pi that changing the direction of the laser with a galvanometer. We developed a program for mosquito tracking in real. The possibility of using deep neural networks, Haar cascades, machine learning for mosquito recognition was considered. We considered in detail the classification problems of mosquitoes in images. A recommendation is given for the implementation of this device based on a microcontroller for subsequent use as part of an unmanned aerial vehicle. Any harmful insects in the fields can be used as objects for control.
ARTICLE | doi:10.20944/preprints202002.0258.v2
Subject: Life Sciences, Genetics Keywords: SARS-CoV-2; cell-entry receptor; ACE2; The Cancer Genome Atlas; susceptibility; demographic factors; polymorphism
Online: 25 February 2020 (06:30:17 CET)
The recurrent coronavirus outbreaks in China (SARS-CoV and its relative, SARS-CoV-2) have raised speculations that perhaps Asians are somehow more susceptible to these coronaviruses. Here, we test this possibility based on an analysis of the lung-specific expression of ACE2, which encodes the known cell-entry receptor of both SARS-CoV and SARS-CoV-2. We show that ACE2 expression is not affected during tumorigenesis, supporting that the abundant transcriptomes in cancer genomic studies can be informatively used to study ACE2 expression among diverse individuals without cancer. We find that ACE2 expression in the lung increases with age, but is not associated with sex. Further, Asians do not differ from other populations for ACE2 expression and do not harbor unique genetic polymorphisms in the ACE2 locus. Thus, beyond illustrating an innovative method for assessing the potential impacts of demographic factors for non-cancer diseases from large-scale cancer sample datasets, our statistically robust findings emphasize that individuals of all races require the same level of personal protection against SARS-CoV-2.
ARTICLE | doi:10.20944/preprints202002.0051.v3
Subject: Life Sciences, Microbiology Keywords: Wuhan 2019-nCov; ACE2; expression; susceptibility; race; age; gender; smoking; single cell
Online: 2 March 2020 (01:38:52 CET)
In current severe global emergency situation of 2019-nCov outbreak, it is imperative to identify vulnerable and susceptible groups for effective protection and care. Recently, studies found that 2019-nCov and SARS-nCov share the same receptor, ACE2. In this study, we analyzed five large-scale bulk transcriptomic datasets of normal lung tissue and two single-cell transcriptomic datasets to investigate the disparities related to race, age, gender and smoking status in ACE2 gene expression and its distribution among cell types. We didn’t find significant disparities in ACE2 gene expression between racial groups (Asian vs Caucasian), age groups (>60 vs <60) or gender groups (male vs female). However, we observed significantly higher ACE2 gene expression in former smoker’s lung compared to non-smoker’s lung. Also, we found higher ACE2 gene expression in Asian current smokers compared to non-smokers but not in Caucasian current smokers, which may indicate an existence of gene-smoking interaction. In addition, we found that ACE2 gene is expressed in specific cell types related to smoking history and location. In bronchial epithelium, ACE2 is actively expressed in goblet cells of current smokers and club cells of non-smokers. In alveoli, ACE2 is actively expressed in remodelled AT2 cells of former smokers. Together, this study indicates that smokers especially former smokers may be more susceptible to 2019-nCov and have infection paths different with non-smokers. Thus, smoking history may provide valuable information in identifying susceptible population and standardizing treatment regimen.
REVIEW | doi:10.20944/preprints201610.0095.v1
Subject: Engineering, Other Keywords: aerofoil; CFD; lift and drag force; pressure and velocity contour
Online: 22 October 2016 (11:08:56 CEST)
NACA 0015 and NACA 4415 aerofoil are most common four digits and broadly used aerodynamic shape. Both of the shapes are extensively used for various kind of applications including turbine blade, aircraft wing and so on. NACA 0015 is symmetrical and NACA 4415 is unsymmetrical in shape. Consequently, they have big one-of-a-kind in aerodynamic traits at the side of widespread differences of their utility and performance. Both of them undergo the same fluid principle while applied in any fluid medium giving dissimilar outcomes in aerodynamics behavior. On this work, experimental and numerical investigation of each NACA 0015 and NACA 4415 is done to decide their performance. For this purpose, aerofoil section is tested for a prevalence range attack of angle (AOA). The study addresses the performance of NACA 0015 and NACA 4415 and evaluates the dynamics of flow separation, lift, drag, pressure and velocity contour and so on. This additionally enables to layout new optimistic aerofoil, which is critical to enhance the efficiency and performance of an aircraft in terms of lift enhancement and drag reduction.
ARTICLE | doi:10.20944/preprints202007.0129.v1
Online: 7 July 2020 (16:26:57 CEST)
The effect of the COVID-19 pandemic in a developing country like Bangladesh is enormous. A research conducted by South Asian network of Economic Modelling predicted that the pandemic could double the poverty. But it is not that only the socioeconomic condition is dropping in Bangladesh, the impact of COVID-19 pandemic is manifold. The poor condition of Bangladesh's health sector has also been exposed due to the pandemic. People are not getting proper treatment due to lack of isolation beds, oxygen, ICU etc. The health sector of Bangladesh is not much developed and now with this pandemic it has become impossible to provide treatment facility for all the patients. Education sector, which is the backbone of a country,has also been greatly affected by the pandemic. We know that different types of cultural occasions are an inherited tradition of Bangladesh, COVID-19 have not even spared these traditions, all the cultural programes and festivals have been cancelled due to this pandemic.In this paper, our aim is to present the present status of all these sectors.
ARTICLE | doi:10.20944/preprints201807.0366.v1
Online: 19 July 2018 (15:43:50 CEST)
This paper investigates how Islamic tolerance contributes to solve religious conflict today that has impacted on various aspects such as economic collapse, insecurity in life, lack of professional society, academic retrogressions, and so on. Knowledge of these issues has become an urgent to build a community that is full of peace, harmony and unity. The paper suggests that Quranic views on tolerance should be understood and practiced in order to avoid disunity in society which is due to failure to appreciate tolerance values in association. The paper concludes problems or misunderstandings always occur in different religious societies, since every religion has its own teachings and principles, as well as each of them is interpreted in different ways.
ARTICLE | doi:10.20944/preprints201809.0484.v1
Subject: Behavioral Sciences, General Psychology Keywords: Bestiality; Colombia; sexual behavior; sexuality; Zoophilia
Online: 25 September 2018 (11:49:12 CEST)
Introduction: Sex with animals is a male practice with a social acceptance in many areas of the Colombian Atlantic coast; however, this behavior has been little studied. The aim of this study was to characterize the practice of sex with animals in a group of men living in Cordoba department, Colombia. Methods: descriptive quantitative study was made. Forty-seven adults were interviewed. The information was collected through a survey which asked about sociodemographic aspects, characteristics and beliefs around the behavior. Results: Total participants knew about the practice, 68,1% stated to have had it and they said it happened between the ages of 7 and 30 years old, for an average time of seven years gap; 65,6% had it in presence of friends and relatives. 87,6% said the practice feels really good at the first time; 35,6% stated it was a beneficial practice and 37,5% said they would like their sons to experience it. Conclusion: Having sex with animals is a social accepted behavior and it is thought to be positive since it helps the correct psychosexual development and it prevents other behaviors, not culturally accepted, such as drug use or homosexuality.
ARTICLE | doi:10.20944/preprints201608.0008.v1
Subject: Engineering, Energy & Fuel Technology Keywords: horizontal axis tidal turbine; Computational Fluid Dynamics; mesh independency; NACA 0018
Online: 2 August 2016 (04:45:13 CEST)
This paper numerically investigates a 3D mesh independency study of a straight blade horizontal axis tidal turbine modelled using Computational Fluid Dynamics (CFD). The solution was produced by employing two turbulence models, the standard k-ε model and Shear Stress Transport (SST) in ANSYS CFX. Three parameters were investigated: mesh resolution, turbulence model, and power coefficient in the initial CFD, analysis. It was found that the mesh resolution and the turbulence model affect the power coefficient results. The power coefficients obtained from the standard k-ε model are 15% to 20% lower than the accuracy of the SST model. It can also be demonstrated that the torque coefficient increases with the increasing Tip Speed Ratio (TSR), but drops drastically after TSR = 5 and k-ε model failing to capture the non-linearity in the torque coefficient with the increasing TSR.
ARTICLE | doi:10.20944/preprints201711.0166.v1
Subject: Engineering, Civil Engineering Keywords: high-rise buildings; architecture; structural solutions; interaction; SWOT analysis
Online: 26 November 2017 (12:45:01 CET)
The article reveals distinctive features of the interaction between architectural and structural solutions for the design of tall buildings as well as spotlights the most distinctive cases of expression. In the contemporary world, interaction is turning into the antithesis of the formerly dominant utilitarian attitude and standardization of tall buildings architectural solutions. Meanwhile, the search for rational structural solutions leads to new possibilities of architectural expression. This necessitates the transformation of a structural solution and its adaptation to the need of a modern architect to be exceptional and noticed. Interaction covers the current as well as retrospective and perspective periods. SWOT analysis was used by the authors of the article to assess the interaction between architectural and structural solutions in tall buildings design, select the most important criteria that could be used searching for rational architectural and structural solutions in future by applying multi-criteria decision making methods.
ARTICLE | doi:10.20944/preprints202008.0246.v2
Subject: Social Sciences, Education Studies Keywords: COVID-19; university student; socio-demographic factors, satisfaction; perception; online learning; mental health; habits; institutions; continents
Online: 19 August 2020 (08:20:09 CEST)
The paper presents the most comprehensive and large-scale study to date on how students perceive the impacts of the COVID-19 crisis on various aspects of their lives on a global level. With a sample of 30,383 students from 62 countries, the study reveals that amid the worldwide lockdown and transition to online learning students were most satisfied with the support provided by teaching staff and their universities’ public relations. Still, deficient computer skills and the perception of a higher workload prevented them from perceiving their own improved performance in the new teaching environment. Students were mainly concerned about issues to do with their future professional career and studies, and experienced boredom, anxiety and frustration. The pandemic has led to the adoption of particular hygienic behaviours (e.g. wearing masks, washing hands) and discouraged certain daily practices (e.g. leaving home, shaking hands). Students were also more satisfied with the role played by hospitals and universities during the epidemic compared to the government and banks. The findings also show that students with selected socio-demographic characteristics (male, part-time, first level, applied sciences, lower living standard, from Africa or Asia) were generally more strongly affected by the pandemic since they were significantly less satisfied with their academic work/life. Key factors influencing students' satisfaction with the role of their university are also identified. Policymakers and higher education institutions around the world may benefit from these findings while formulating policy recommendations and strategies to support students during this and any future pandemics.
ARTICLE | doi:10.20944/preprints202003.0214.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: SARS-Cov-2; Citrus sp.; Galangal; Curcuma sp.; Sappan wood
Online: 12 March 2020 (13:59:40 CET)
COVID-19 pandemic is a serious problem in the world today. The SARS-CoV-2 virus that causes COVID-19 has important proteins used for its infection and development, namely the protease and spike glycoprotein. The RBD (Receptor Binding Domain) of spike glycoprotein (RBD-S) can bind to the ACE2 (Angiotensin Converting Enzyme-2) receptor at the protease domain (PD) (PD-ACE2) of the host cell, thereby leading to a viral infection. This study aims to reveal the potential of compounds contained in Curcuma sp., Citrus sp., Alpinia galanga, and Caesalpinia sappan as anti SARS-CoV-2 through its binding to 3 protein receptors. The study was conducted by molecular docking using the MOE 2010 program (licensed from Faculty of Pharmacy UGM, Indonesia). The selected protein targets are RBD-S (PDB ID:6LXT), PD-ACE2 (PDB ID: 6VW1), and SARS-CoV-2 protease (PDB ID:6LU7). The affinities of bonds formed is represented as a docking score. The results show that hesperidin, one of the compounds in Citrus sp., has the lowest docking score for all three protein receptors representing the highest affinity to bind the receptors. Moreover, all of the citrus flavonoids possess good affinity to the respected receptors as well as curcumin, brazilin, and galangin, indicating that those compounds perform inhibitory potential for the viral infection and replication. In general, the results of this study indicate that Citrus sp. exhibit the best potential as an inhibitor to the development of the SARS-CoV-2, followed by galangal, sappan wood, and Curcuma sp. that can be consumed in daily life as prophylaxis of COVID-19.
HYPOTHESIS | doi:10.20944/preprints202001.0358.v3
Subject: Medicine & Pharmacology, Other Keywords: SARS-CoV-2 (2019-nCoV); Baicalin; Scutellarin; Hesperetin; Nicotianamine; Glycyrrhizin
Online: 10 March 2020 (05:09:22 CET)
SARS-CoV-2 (2019-nCoV), a novel coronavirus, caused the pneumonia outbreak in China and continue to expand. The host receptor for 2019-nCoV Angiotensin-converting enzyme 2 (ACE2), is the same as the host receptor for SARS-CoV. Targeting ACE2 holds the promise for preventing and inhibiting 2019-nCoV infection. Chinese Medicine herbs could be a valuable pool for identifying active compounds for treating infection of 2019-nCoV. In this study, we summarize several active compounds, including baicalin, Scutellarin, Hesperetin, Nicotianamine and glycyrrhizin that could have potential anti-2019-nCoV effects. We conduct molecular docking to predict their capacity for binding ACE2, which may prevent the 2019-nCoV infection. We propose that these selected compounds worth further investigation for preventing 2019-nCoV.
ARTICLE | doi:10.20944/preprints201710.0138.v1
Subject: Arts & Humanities, Religious Studies Keywords: preservation; environment; quran; issues; Malaysia
Online: 20 October 2017 (10:11:16 CEST)
Currently, various issues on environment have been discussed, whether the importance, destruction or ways to prevent the destruction of the environment. This paper will explore the issue from the conventional viewpoint as well as from the Islamic perspective. Destruction of the environment in recent times has worsened due to the uncontrolled exploitation of natural resources by human beings in order to generate profits. In view of the increasing technological development in Malaysia presently, this matter should not have occurred because the citizens intellectual abilities can be considered advanced. In other words, these people should be able to weigh between positive and negative consequences of voraciously exploiting natural resources. However, the greed that engulfs some of these people has obscured their view from grasping the future consequences of their acts. Based on the Islamic perspective in which the Quran is the ultimate reference, destruction of the environment can actually be prevented if every individual is aware of his or her trustworthiness or responsibility as His caliphate in this universe. Nevertheless, is there any specific verse in the Quran which explains about preservation of the environment? Can lessons from the Quran provide solutions to the environmental crises in Malaysia? This study provides explanations to the questions based on literature surveys and content analyses. By interpreting some selected verses that relate to preservation of the environment, findings from the discussions have identified that the Quranic verses are valuable resources for the sustainability of the environment.
ARTICLE | doi:10.20944/preprints202208.0151.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: BNT162b2 mRNA COVID-19 vaccine; COVID-19 vaccine; cardiovascular effects; myocarditis; adolescents; Thailand
Online: 8 August 2022 (10:40:23 CEST)
This study focuses on cardiovascular effects, particularly myocarditis and pericarditis events, after BNT162b2 mRNA COVID-19 vaccine injection in Thai adolescents. This prospective cohort study enrolled students from two schools aged 13–18 years who received the second dose of the BNT162b2 mRNA COVID-19 vaccine. Data including demographics, symptoms, vital signs, ECG, echocardiography and cardiac enzymes were collected at baseline, Day 3, Day 7, and Day 14 (optional) using case record forms.We enrolled 314 participants; of these, 13 participants were lost to follow up, leaving 301 participants for analysis. The most common cardiovascular effects were tachycardia (7.64%), shortness of breath (6.64%), palpitation (4.32%), chest pain (4.32%), and hypertension (3.99%). Seven participants (2.33%) exhibited at least one elevated cardiac biomarker or positive lab assessments. Cardiovascular effects were found in 29.24% of patients, ranging from tachycardia, palpitation, and myopericarditis. Myopericarditis was confirmed in one patient after vaccination. Two patients had suspected pericarditis and four patients had suspected subclinical myocarditis. Conclusion: Cardiovascular effects in adolescents after BNT162b2 mRNA COVID-19 vaccination included tachycardia, palpitation, and myocarditis. The clinical presentation of myopericarditis after vaccination was usually mild, with all cases fully recovering within 14 days. Hence, adolescents receiving mRNA vaccines should be monitored for side effects. Clinical Trial Registration: NCT05288231
REVIEW | doi:10.20944/preprints202005.0070.v2
Subject: Life Sciences, Virology Keywords: Covid; covid-19; sars-cov-2; temperature; heat; body temperature; air temperature; viral decay; viral stability; transmission; severity; virology; thermodynamics
Online: 6 September 2021 (13:23:23 CEST)
Currently available data are consistent with increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication at temperatures encountered in the upper airways (25–33°C when breathing room temperature air, 25°C) compared to those in the lower airways (37°C). One factor that may contribute to more rapid viral growth in the upper airways is the exponential increase in SARS-CoV-2 stability that occurs with reductions in temperature, as measured in vitro. Because SARS-CoV-2 frequently initiates infection in the upper airways before spreading through the body, increased upper airway viral growth early in the disease course may result in more rapid progression of disease and potentially contribute to more severe outcomes. Similarly, higher SARS-CoV-2 viral titer in the upper airways likely supports more efficient transmission. Conversely, the possible significance of air temperature to upper airway viral growth suggests that prolonged delivery of heated air might represent a preventative measure and prophylactic treatment for coronavirus disease 2019.
ARTICLE | doi:10.20944/preprints201903.0131.v1
Subject: Engineering, Energy & Fuel Technology Keywords: energy consumption; prediction; machine learning models; deep learning models; 21 artificial intelligence (AI); computational intelligence (CI); forecasting; soft computing (SC)
Online: 11 March 2019 (10:09:33 CET)
Machine learning (ML) methods has recently contributed very well in the advancement of the prediction models used for energy consumption. Such models highly improve the accuracy, robustness, and precision and the generalization ability of the conventional time series forecasting tools. This article reviews the state of the art of machine learning models used in the general application of energy consumption. Through a novel search and taxonomy the most relevant literature in the field are classified according to the ML modeling technique, energy type, perdition type, and the application area. A comprehensive review of the literature identifies the major ML methods, their application and a discussion on the evaluation of their effectiveness in energy consumption prediction. This paper further makes a conclusion on the trend and the effectiveness of the ML models. As the result, this research reports an outstanding rise in the accuracy and an ever increasing performance of the prediction technologies using the novel hybrid and ensemble prediction models.
REVIEW | doi:10.20944/preprints201704.0137.v1
Subject: Chemistry, Chemical Engineering Keywords: process simulation; kinetic modelling; ammonia; methanol; bioethanol; steam reforming; ethylene
Online: 21 April 2017 (10:00:46 CEST)
Process simulation represents an important tool for plant design and optimisation, either applied to well established or to newly developed processes. Suitable thermodynamic packages should be selected in order to properly describe the behaviour of reactors and unit operations and to precisely define phase equilibria. Moreover, a detailed and representative kinetic scheme should be available to predict correctly the dependence of the process on its main variables. This review points out some models and methods for kinetic analysis specifically applied to the simulation of catalytic processes, as a basis for process design and optimisation. Attention is paid also to microkinetic modelling and to the methods based on first principles, to elucidate mechanisms and calculate thermodynamic and kinetic parameters. Different case histories support the discussion. At first, we have selected two basic examples from the industrial chemistry practice, e.g. ammonia and methanol synthesis, which may be described through a relatively simple reaction pathway. Then, a more complex reaction network is deeply discussed to define the conversion of bioethanol into syngas/hydrogen or into building blocks, such as ethylene.
REVIEW | doi:10.20944/preprints202003.0275.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: Antimalarial; Chemoprophylaxis; Chloroquine; Coronavirus; COVID-19; Global Health; Hydroxychloroquine; Public Health; SARS-CoV-2; Virus
Online: 17 March 2020 (09:17:53 CET)
There is a long trail of research studies testing the in vitro and in vivo efficacy of chloroquine and its derivatives in treating and preventing infection by various coronavirus species. More recent findings have highlighted the possibility of treating patients infected with the 2019 novel coronavirus, SARS-CoV-2. This review describes the mechanism of coronavirus infection, the mechanism of action of chloroquine, and summarizes the available literature highlighting the efficacy of chloroquine as an anti-coronavirus agent. These findings should encourage the wider scientific community to conduct thorough research on the possible efficacy of chloroquine and its derivatives in treating and preventing SARS-CoV-2 infection.
ARTICLE | doi:10.20944/preprints201808.0422.v1
Subject: Social Sciences, Organizational Economics & Management Keywords: Logistics; Logistical Centralization; Logistical Decentralization
Online: 23 August 2018 (23:37:23 CEST)
In the area of health, namely hospitals, we can agree that the intrinsic need to have multidisciplinary teams, highly specialized and indispensable resources leads us to a degree of complexity that requires, daily, the best performance, not running away from the logistics area to the rule. The centralization of resources, namely distribution warehouses, emerges as a challenge and possible solution for health institutions to respond in the best possible way to their main purpose: to put the right material in the right place at the right price in the right time space. As regards the advantages of this type of organization, there are several authors who argues that the need for human resources training, ease of coordination and the use of economies of scale are the main advantage. As far as the disadvantages are concerned, there is no special agreement on them, there are disparate factors from author to author, such as: routine, centralization, objectives or operation costs.
REVIEW | doi:10.20944/preprints202003.0235.v2
Subject: Medicine & Pharmacology, Nutrition Keywords: acute respiratory distress syndrome (ARDS); ascorbic acid; cathelicidin; coronavirus; COVID-19; cytokine storm; influenza; observational; pneumonia, prevention; respiratory tract infection; solar radiation; treatment; UVB; vitamin C; vitamin D
Online: 30 March 2020 (05:48:43 CEST)
The world is in the grips of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increase concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D [25(OH)D] concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome, and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40–60 ng/ml (100–150 nmol/l). For treatment of people who become infected with COVID-19, higher vitamin D3 doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.
REVIEW | doi:10.20944/preprints201811.0601.v1
Subject: Engineering, Civil Engineering Keywords: Drone, Remote Sensing, control station, Multispectral, Aviation, Regulations
Online: 27 November 2018 (12:08:39 CET)
In past few years, unmanned aerial vehicles (UAV) or drones has been a hot topic encompassing technology, security issues, rules and regulations globally due to its remarkable advancements and uses in remote sensing and photogrammetry applications. This review paper highlights the evolution and development of UAV, classification and comparison of UAVs along with Hardware and software design challenges with diverse capabilities in civil and military applications. Further, safety and security issues with drones, existing regulations and guidelines to fly the drone, limitations and possible solutions have also been discussed.
Online: 12 March 2020 (03:15:15 CET)
The COVID19 coronavirus SARS-CoV2 spreading in Wuhan and now worldwide has been shown to use angiotensin-converting enzyme 2 ACE2 as its host cell receptor, like the severe acute respiratory syndrome coronavirus (SARS-CoV). Epidemiology studies found different sex and age groups have different susceptibility to infection, and very skewed severity and mortality of the virus infection, with male, old age, and comorbidity being the most inflicted. Here by analyzing GTEx and other public data in 30 tissues across thousands of individuals, we found significantly higher expression in Asian females compared to males and other ethnic groups, an age dependent ACE2 expression decrease and a highly significant decrease in type II diabetic patients. Consistently, the most significant expression quantitative loci (eQTLs) contributing to high ACE2 expression are close to 100% in East Asians, >30% higher than other ethnic groups. Together with the shockingly common enrichment of viral infection pathways among ACE2 anti-expressed genes, binding of virus infection-related transcription factors at ACE2 regulatory regions, the repression of ACE2 expression by inflammatory cytokines and by type 2 diabetes, and the induction by estrogen and androgen (both decrease with age) established a negative correlation between ACE2 expression and CovID19 fatality at both population and molecular levels. Our results will be instrumental when designing potential prevention and treatment strategies for ACE2 binding coronaviruses in general.
REVIEW | doi:10.20944/preprints201808.0379.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Climate change, Developing countries, Environmental change, Forest, Population growth
Online: 21 August 2018 (14:00:04 CEST)
This review paper is intended to exhibit the interplays between environmental change and rapid population growth in developing countries. In the course of discussion, the impacts of rapidly population growing on the environment have been discussed, and evidence, from various parts of the world have been traced. Studies on the impacts of population pressure on environment have been critically reviewed. It is revealed that all across the developing countries, farm size is shrinking as farmers continue to subdivide holdings among their children. In countries such as Malawi, Rwanda, Ethiopia, Haiti, Nepal and Bangladesh, population growth rates are high, and the non-farm sector is still in its early stages of development. Demographic pressure, land scarcity, and land fragmentation drive greater rural vulnerability and poverty, marked by decreased food security, inadequate response to such natural disasters such as drought or pest infestations, weakened resilience to shocks, and poor health. It is not just the supply of food, fodder, and fuel wood but the resource base itself and the lives that depend upon it are being affected. The evidences pinpoints that man through his non-sustainable production and consumption patterns, is placed at the heart of environmental changes. However, contradictory view, and practices are also in place that the population growth has positive impacts environmental restoration and improvements, while other evidences show insignificant effect of population on the environment. This contradicting scenario puts scholars in argument, and still need further research. Hence, it would be a blind generalization to draw conclusion from this relationship alone, rather, another factor that acts beyond population pressure must also be considered to justify the impact of population on environmental changes.
ARTICLE | doi:10.20944/preprints202003.0444.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: COVID-19; SARS-CoV-2; coronavirus; novel coronavirus; 3D printing; N95; respirator; mask
Online: 31 March 2020 (04:44:06 CEST)
The 2019 Novel Coronavirus (COVID-19) has caused an acute reduction in world supplies of personal protective equipment (PPE) due to increased demand. To combat the impending shortage of equipment including N95 masks, the George Washington University Hospital (GWUH) developed a 3D printed reusable N95 comparable respirator that can be used with multiple filtration units. We evaluated several candidate prototype respirator models, 3D printer filaments, and filtration units detailed here. Our most recent working model was based on a respirator found on an open source maker website and was developed with PLA (printer filament), a removable cap, a removable filtration unit consisting of two layers of MERV 16 sandwiched between MERV 13, and removable elastic bands to secure the mask. Our candidate mask passed our own suction test protocol to evaluate leakage and passed a qualitative Bitrix N95 fit test at employee health at GWUH. Further efforts are directed at improving the current model for seal against face, comfort, and sizing. The 3D model is available upon request and in the supplement of this paper. We welcome collaboration with other institutions and suggest other facilities consider mask fit for their own population when exploring this concept.
ARTICLE | doi:10.20944/preprints202006.0013.v1
Subject: Social Sciences, Education Studies Keywords: online education; corona crisis; challenges; possibilities
Online: 3 June 2020 (08:25:46 CEST)
Online class now is the demand of the day as little scopes are to find out alternatives to online class in these unprecedented days caused by corona pandemic across the globe. The study was qualitative in approach and data were collected from secondary sources i.e. different newspapers and journals in the recent times along with a mini interview with students of private universities studying in different subjects over mobile phone by the researcher. Findings of the study show that though online education has a number of challenges faced by two main stakeholders; students and teachers, handling all these challenges carefully can have the chance to create a positive atmosphere in the field of education as an alternative teaching learning resulting in positive outcomes in all regards.
HYPOTHESIS | doi:10.20944/preprints202004.0023.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; bradykinin; ACE2; pulmonary angioedema; ARDS; icatibant
Online: 3 April 2020 (04:13:43 CEST)
Most striking observations in COVID-19 patients are the hints on pulmonary edema (also seen on CT scans as ground glass opacities), dry cough, fluid restrictions to prevent more severe hypoxia, the huge PEEP that is needed while lungs are compliant, and the fact that anti-inflammatory therapies are not powerful enough to counter the severity of the disease. We propose that the severity of the disease and many deaths are due to a local vascular problem due to activation of B1 receptors on endothelial cells in the lungs. SARS-CoV-2 enters the cell via ACE2, a cell membrane bound molecule with enzymatic activity that next to its role in RAS is needed to inactivate des-Arg9 bradykinin, the potent ligand of the bradykinin receptor type 1 (B1). In contrast to bradykinin receptor 2 (B2), the B1 receptor on endothelial cells is upregulated by proinflammatory cytokines. Without ACE2 acting as a guardian to inactivate the ligands of B1, the lung environment is prone for local vascular leakage leading to angioedema. Angioedema is likely a feature already early in disease, and might explain the typical CT scans and the feeling of people that they drown. In some patients, this is followed by a clinical worsening of disease around day 9 due to the formation antibodies directed against the spike (S)-antigen of the corona-virus that binds to ACE2 that could contribute to disease by enhancement of local immune cell influx and proinflammatory cytokines leading to damage. In parallel, inflammation induces more B1 expression, and possibly via antibody-dependent enhancement of viral infection leading to continued ACE2 dysfunction in the lung because of persistence of the virus. In this viewpoint we propose that a bradykinin-dependent local lung angioedema via B1 and B2 receptors is an important feature of COVID-19, resulting in a very high number of ICU admissions. We propose that blocking the B1 and B2 receptors might have an ameliorating effect on disease caused by COVID-19. This kinin-dependent pulmonary edema is resistant to corticosteroids or adrenaline and should be targeted as long as the virus is present. In addition, this pathway might indirectly be responsive to anti-inflammatory agents or neutralizing strategies for the anti-S-antibody induced effects, but by itself is likely to be insufficient to reverse all the pulmonary edema. Moreover, we provide a suggestion of how to ventilate in the ICU in the context of this hypothesis.
ARTICLE | doi:10.20944/preprints201607.0013.v1
Subject: Social Sciences, Finance Keywords: capital structure, total debt ratio, profitability, return on assets, firms, Ethiopia
Online: 8 July 2016 (10:42:31 CEST)
This study was aimed to investigate the effect of capital structure on firms’ profitability with special emphasis on Ethiopian Large Private Manufacturing Firms using panel data of five consecutive years (2006/07-2010/11G.C). The secondary data sources (audited financial statements) have been collected from the randomly selected thirty three large private manufacturing firms in Ethiopia. Linear regression model has been employed to analyze the relationship between firms’ profitability and capital structure. Specifically, Random-effect Generalized Least Square of panel data regression model has been selected to empirically test the literature driven hypotheses. Finally, the findings of this study revealed that a significant positive relationship between firms’ profitability and total debt ratio which indicate firm’s capital structure.
ARTICLE | doi:10.20944/preprints202003.0333.v1
Online: 23 March 2020 (04:30:47 CET)
COVID-19, a rapidly spreading new strain of coronavirus, has affected more than 150 countries and received worldwide attention. The lack of efficacious drugs or vaccines against SARS-CoV-2 has further worsened the situation. Thus, there is an urgent need to boost up research for the development of effective therapeutics and affordable diagnostic against COVID-19. The crystallized form of SARS-CoV-2 main protease (Mpro) was demonstrated by a Chinese researcher Liu et al. (2020) which is a novel therapeutic drug target. This study was conducted to evaluate the efficacy of medicinal plant-based bioactive compounds against COVID-19 Mpro by molecular docking study. Molecular docking investigations were performed by using Molegro Virtual Docker 7 to analyze the inhibition probability of these compounds against COVID-19. COVID-19 Mpro was docked with 80 flavonoid compounds and the binding energies were obtained from the docking of (PDB ID: 6LU7: Resolution 2.16 Å) with the native ligand. According to obtained results, hesperidin, rutin, diosmin, apiin, diacetylcurcumin, (E)-1-(2-Hydroxy-4-methoxyphenyl)-3-[3-[(E)-3-(2-hydroxy-4- methoxyphenyl)-3-oxoprop-1-enyl]phenyl]prop-2-en-1-one, and beta,beta'-(4-Methoxy-1,3- phenylene)bis(2'-hydroxy-4',6'-dimethoxyacrylophenone have been found as more effective on COVID-19 than nelfinavir. So, this study will pave a way for doing advanced experimental research to evaluate the real medicinal potential of these compounds to cure COVID-19.
ARTICLE | doi:10.20944/preprints202004.0458.v1
Online: 25 April 2020 (10:31:39 CEST)
The COVID-19 has caused gigantic negative effects on populace wellbeing, society, education, and the economy in Bangladesh. The aim is to deliver a comprehensive overview of the observed and the possible impacts that could appear in the coming days. The study is based on secondary information. During the early period, due to a lack of accurate facts about the case affected and death tension up-and-down among the nations. The total number of confirmed cases is increasing following geometric patterns in Bangladesh. Dairy farmers, vegetable producers, pharmaceuticals, poultry farmers are in deep crisis due to lower prices. Also, the pandemic has seriously affected educational systems, banking, FDI, ready-made garments, remittances, etc Finally, it is not possible to mitigate the effects of pandemic individually but the integrated effort from the state authority as well as concern people of all sectors need to come forward.
HYPOTHESIS | doi:10.20944/preprints202004.0124.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; SARS-CoV-2; Therapy; Chloroquine; Hydroxychloroquine; Zinc
Online: 8 April 2020 (10:54:33 CEST)
Currently, drug repurposing is an alternative to novel drug development for the treatment of COVID-19 patients. The antimalarial drug chloroquine (CQ) and its metabolite hydroxychloroquine (HCQ) are currently being tested in several clinical studies as potential candidates to limit SARS-CoV-2-mediated morbidity and mortality. CQ and HCQ (CQ/HCQ) inhibit pH-dependent steps of SARS-CoV-2 replication by increasing pH in intracellular vesicles and interfere with virus particle delivery into host cells. Besides direct antiviral effects, CQ/HCQ specifically target extracellular zinc to intracellular lysosomes where it interferes with RNA-dependent RNA polymerase activity and coronavirus replication. As zinc deficiency frequently occurs in elderly patients and in those with cardiovascular disease, chronic pulmonary disease, or diabetes, we hypothesize that CQ/HCQ plus zinc supplementation may be more effective in reducing COVID-19 morbidity and mortality than CQ or HCQ in monotherapy. Therefore, CQ/HCQ in combination with zinc should be considered as additional study arm for COVID-19 clinical trials.
Subject: Social Sciences, Accounting Keywords: Semi-structured Interview; SSI; In-depth interview; Strength and Weakness
Online: 21 June 2021 (08:52:20 CEST)
A semi-structured interview (SSI) is one of the essential tools in conduction qualitative research. This essay draws upon the pros and cons of applying semi-structured interviews (SSI) in the qualitative research method. Moreover, the challenges of SSI during the coronavirus pandemic are critically discussed to provide plausible recommendations.
Subject: Medicine & Pharmacology, Allergology Keywords: antibodies; COVID-19; glycans; immunoglobulin M; SARS-CoV-2; pneumonia; prediction; protection
Online: 24 April 2020 (10:25:27 CEST)
The natural history of COVID-19 caused by SARS-CoV-2 is extremely variable, ranging from asymptomatic infection, to pneumonia, and to complications eventually fatal. We propose here the first model, explaining how the outcome of first, crucial 10-15 days after infection, hangs on the balance between the cumulative dose of viral exposure and the efficacy of the local innate immune response (natural IgA and IgM antibodies, MBL). If SARS-CoV-2 runs the blockade of this innate immunity and spreads from the upper airways to the alveoli in the early phases of the infections, it can replicate with no local resistance, causing pneumonia and releasing high amounts of antigens. The delayed and strong adaptive immune response (high affinity IgM and IgG antibodies) that follows, causes severe inflammation and triggers mediator cascades (complement, coagulation, and cytokine storm) leading to complications often requiring intensive therapy and being, in some patients, fatal. Strenuous exercise and high flow air in the incubation days and early stages of COVID-19, facilitates direct penetration of the virus to the lower airways and the alveoli, without impacting on the airway’s mucosae covered by neutralizing antibodies. This allows the virus to bypass the efficient immune barrier of the upper airways mucosa in young and healthy athletes. In conclusion, whether the virus or the adaptative immune response reach the lungs first, is a crucial factor deciding the fate of the patient. This “quantitative and time-sequence dependent” model has several implications for prevention, diagnosis, and therapy of COVID-19.
REVIEW | doi:10.20944/preprints202010.0330.v2
Subject: Medicine & Pharmacology, Allergology Keywords: COVID-19; Public Health; Lockdowns; Cost-benefit analysis; Groupthink
Online: 4 November 2020 (10:14:33 CET)
The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused the Coronavirus Disease 2019 (COVID-19) worldwide pandemic in 2020. In response, most countries in the world implemented lockdowns, restricting their population’s movements, work, education, gatherings, and general activities in attempt to ‘flatten the curve’ of COVID-19 cases. The public health goal of lockdowns was to save the population from COVID-19 cases and deaths, and to prevent overwhelming health care systems with COVID-19 patients. In this narrative review I explain why I changed my mind about supporting lockdowns. First, I explain how the initial modeling predictions induced fear and crowd-effects [i.e., groupthink]. Second, I summarize important information that has emerged relevant to the modeling, including about infection fatality rate, high-risk groups, herd immunity thresholds, and exit strategies. Third, I describe how reality started sinking in, with information on significant collateral damage due to the response to the pandemic, and information placing the number of deaths in context and perspective. Fourth, I present a cost-benefit analysis of the response to COVID-19 that finds lockdowns are far more harmful to public health than COVID-19 can be. Controversies and objections about the main points made are considered and addressed. I close with some suggestions for moving forward.
ARTICLE | doi:10.20944/preprints201710.0008.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: : microstrip antenna, vertical slots , adaptive network-based fuzzy Inference system , resonant frequency, artificial neural networks
Online: 2 October 2017 (09:16:02 CEST)
This paper attempts at applying adaptive network-based fuzzy inference system (ANFIS) for analysis of the resonant frequency of a microstrip rectangular patch antenna with two equal size slots which are placed on the patch vertically. The resonant frequency is calculated as the position of slots is shifted to the right and left sides on the patch. As a result , the antenna resonates at more than one frequency . Commonly, machine algorithms based on artificial neural networks are employed to recognize the whole resonant frequencies. However ,they fail to estimate the resonant frequencies correctly as in some cases variations are not very sensible and the resonant frequencies overlap each other . It can be concluded that artificial neural networks could be replaced in such designs by the adaptive network-based fuzzy Inference system due to its high approximation capability and much faster convergence rate.
ARTICLE | doi:10.20944/preprints202003.0422.v1
Online: 29 March 2020 (06:16:20 CEST)
Currently, the world is struggling with the coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Prion-like domains are critical for virulence and the development of therapeutic targets; however, the prion-like domains in the SARS-CoV-2 proteome have not been analyzed. In this in silico study, using the PLAAC algorithm, we identified the presence of prion-like domains in the SARS-CoV-2 spike protein. Compared with other viruses, a striking difference was observed in the distribution of prion-like domains in the spike protein, since SARS-CoV-2 was the only coronavirus with a prion-like domain found in the receptor-binding domain of the S1 region of the spike protein. The presence and unique distribution of prion-like domains in the SARS-CoV-2 receptor-binding domains of the spike protein is particularly interesting, since although the SARS-CoV-2 and SARS-CoV S proteins share the same host cell receptor, angiotensin-converting enzyme 2 (ACE2), SARS-CoV-2 demonstrates a 10- to 20-fold higher affinity for ACE2. Finally, we identified prion-like domains in the α1 helix of the ACE2 receptor that interact with the viral receptor-binding domain of SARS-CoV-2. Taken together, the present findings indicate that the identified PrDs in the SARS-CoV-2 receptor-binding domain (RBD) and ACE2 region that interact with RBD have important functional roles in viral adhesion and entry.
REVIEW | doi:10.20944/preprints201705.0090.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Electric Vehicle; internal combustion engine; greenhouse gas; optimization techniques; Battery Electric Vehicle (BEV); Hybrid Electric Vehicle (HEV); Plug-in Hybrid Electric Vehicle (PHEV); Fuel Cell Electric Vehicle (FCEV).
Online: 10 May 2017 (17:44:51 CEST)
Electric vehicles (EV) are getting more commonplace in the transportation sector in recent times. As the present trend suggests, this mode of transport is likely to replace the internal combustion engine (ICE) vehicles in near future. Each of the main EV components has a number of technologies that are currently in use or can become prominent in the future. EVs can cause significant impacts on the environment, power system, and other related sectors. The present power system can face huge instabilities with enough EV penetration; but with proper management and coordination, EVs can be turned into a major contributor to the successful implementation of smart grid. There are possibilities of immense environmental benefits as well, as the EVs can extensively reduce the greenhouse gas emission from the transportation sector. However, there are some major obstacles for EVs to overcome before replacing the ICE vehicles totally. This paper is focused on reviewing all the useful data available on EV configurations, energy sources, motors, charging techniques, optimization techniques, impacts, trends, and possible directions of future developments. Its objective is to provide an overall picture of the current EV technology and ways of future development to assist in future researches in this sector.
ARTICLE | doi:10.20944/preprints201705.0123.v1
Subject: Mathematics & Computer Science, General & Theoretical Computer Science Keywords: Mobile device threats; mobile device malware; reverse proxy server; cyber security; android security; ios security; abuse of local area network; DNS spoofing; DNS hijacking
Online: 16 May 2017 (13:23:18 CEST)
Mobile devices have become tools we spend our free time where we carry them with us every moment, they allow us to interact with the environment, we immortalize the moment when necessary. These devices which we spend most of our daily life become very common in recent years and even there are unique business areas emerged. It was announced that the number of people using smartphones is over than 2.5 billion in the first quarter of 2016. As people become more addicted to mobile technology, they become the target of malevolent people. A huge increase in the number of mobile malware is observed as the number of the users increase. Billions of users at risk day by day due to the development of the methods. We have addressed the recent methods used and the types of malware that target mobile devices in our study. We have mentioned the proxy server and reverse proxy server operation logic. We discuss the method of turning mobile devices into reverse proxy servers, risks involved and protection methods.
ARTICLE | doi:10.20944/preprints201703.0086.v1
Subject: Engineering, General Engineering Keywords: image enhancement; image fusion; color space; edge detector; underwater image
Online: 14 March 2017 (17:52:48 CET)
In order to improve contrast and restore color for underwater image captured by camera sensors without suffering from insufficient details and color cast, a fusion algorithm for image enhancement in different color spaces based on contrast limited adaptive histogram equalization (CLAHE) is proposed in this article. The original color image is first converted from RGB color space to two different special color spaces: YIQ and HSI. The color space conversion from RGB to YIQ is a linear transformation, while the RGB to HSI conversion is nonlinear. Then, the algorithm separately operates CLAHE in YIQ and HSI color spaces to obtain two different enhancement images. The luminance component (Y) in the YIQ color space and the intensity component (I) in the HSI color space are enhanced with CLAHE algorithm. The CLAHE has two key parameters: Block Size and Clip Limit, which mainly control the quality of CLAHE enhancement image. After that, the YIQ and HSI enhancement images are respectively converted backward to RGB color. When the three components of red, green, and blue are not coherent in the YIQ-RGB or HSI-RGB images, the three components will have to be harmonized with the CLAHE algorithm in RGB space. Finally, with 4 direction Sobel edge detector in the bounded general logarithm ratio operation, a self-adaptive weight selection nonlinear image enhancement is carried out to fuse YIQ-RGB and HSI-RGB images together to achieve the final fused image. The enhancement fusion algorithm has two key factors: average of Sobel edge detector and fusion coefficient, and these two factors determine the effects of enhancement fusion algorithm. A series of evaluate metrics such as mean, contrast, entropy, colorfulness metric (CM), mean square error (MSE) and peak signal to noise ratio (PSNR) are used to assess the proposed enhancement algorithm. The experiments results showed that the proposed algorithm provides more detail enhancement and higher values of colorfulness restoration as compared to other existing image enhancement algorithms. The proposed algorithm can suppress effectively noise interference, improve the image quality for underwater image availably.
TECHNICAL NOTE | doi:10.20944/preprints201809.0539.v1
Subject: Mathematics & Computer Science, Probability And Statistics Keywords: Non-normality, Classical Linear Regression Model, Modified Maximum Likelihood Estimation.
Online: 27 September 2018 (10:04:26 CEST)
Regression models form the core of the discipline of econometrics. One of the basic assumptions of classical linear regression model is that the values of the explanatory variables are fixed in repeated sampling. However, in most of the real life cases, particularly in economics the assumption of fixed regressors is not always tenable. Under a non-experimental or uncontrolled environment, the dependent variable is often under the influence of explanatory variables that are stochastic in nature. There is a huge literature related to stochastic regressors in various aspects. In this paper, a historical perspective on some of the works related to stochastic regressor is being tried to pen down based on literature search.
ARTICLE | doi:10.20944/preprints201712.0150.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Philippines; rainfall; precipitation; Gamma distribution; probability; weather risk
Online: 21 December 2017 (04:43:17 CET)
Philippines as an archipelago and tropical country, which is situated near the Pacific ocean, faces uncertain rainfall intensities. This makes environmental, agricultural and economic systems affected by precipitation difficult to manage. Time series analysis of Philippine rainfall pattern has been previously done, but there is no study investigating its probability distribution. Modeling the Philippine rainfall using probability distributions is essential, especially in managing risks and designing insurance products. Here, daily and cumulative rainfall data (January 1961 - August 2016) from 28 PAGASA weather stations are fitted to probability distributions. Moreover, the fitted distributions are examined for invariance under subsets of the rainfall data set. We observe that the Gamma distribution is a suitable fit for the daily up to the ten-day cumulative rainfall data. Our results can be used in agriculture, especially in forecasting claims in weather index-based insurance.
REVIEW | doi:10.20944/preprints202004.0204.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: Covid-19; coronavirus; cardiovascular disease; thrombosis; hypertension; endothelial dysfunction
Online: 13 April 2020 (02:23:33 CEST)
The symptoms most commonly reported by patients affected by coronavirus disease 2019 (COVID-19) include cough, fever, and shortness of breath. However, other major events usually observed in COVID-19 patients (e.g. high blood pressure, thrombosis, pulmonary embolism) seem to suggest that the virus is targeting the endothelium, one of the largest organs in the human body. Herein, we report both clinical and preclinical evidence supporting the hypothesis that the endothelium is a key target organ of COVID-19.
Subject: Social Sciences, Sociology Keywords: depression; measurement scale; ratings; literature review
Online: 16 December 2016 (07:57:02 CET)
The range of rating instruments in depression measurement and the depth of their analytical relevance constitutes a major development in this psychiatric and psychotherapeutic field of mental health. Though the competition is acute amongst these various instruments, the results for the public have been outstandingly positive. A depression rating scale is essentially a psychiatric measuring instrument utilized in the identification and ranking of depression severity within the patient. The scale provides the practitioner, psychiatrist or psychotherapist, with sufficient information to assess the severity of the depression plotted on the scale. Not used as a “diagnostic tool” itself, nevertheless, the depression rating scale does function as an effective device for designating and assigning a behavioral score which may, then, be used in establishing the severity of depression of value in the designation of a diagnosis and treatment formula. In this paper, we will take a close look at the leading depression rating scales and briefly summarize their scope of assessment value in rating depression.
ARTICLE | doi:10.20944/preprints201704.0101.v1
Subject: Social Sciences, Law Keywords: tax taxation power; principles of tax; tax adjudication; constitutional tax rules; Ethiopian constitution; Turkish Constitution
Online: 18 April 2017 (02:41:03 CEST)
Constitutions as supreme legal authorities enshrine the principles of taxation which are often used as the guidance to the legislations related to fiscal aspect, requires to be explored critically so as to provide clear understanding on taxation. This article has explored the tax provisions in the constitutions of Ethiopia and Turkey from comparative perspective through the method of doctrinal legal analysis. Both the latest constitution of Turkey and Ethiopia comprise relatively related principles regarding taxation in spite of the disparities of taxation system in these two countries due to the fact that Turkey is a unitary state whereas Ethiopia is federal. In-fact, there are some disparities within these constitutions. For instance, the 1982 Constitution of Turkey specifies the citizens' duties to pay tax and the adjudication system of tax in different way than the Ethiopian 1995 constitution. The Ethiopian constitution enshrines the taxation power in detail among other things in line with the federal system of government.
ARTICLE | doi:10.20944/preprints202002.0179.v1
Online: 14 February 2020 (02:34:55 CET)
Ongoing outbreak of pneumonia caused by novel coronavirus (2019-nCoV) began in December 2019 in Wuhan, China, and the number of new patients continues to increase. On the contrary to ongoing outbreak in China, however, there are limited secondary outbreaks caused by exported case outside the country. We here conducted simulations to estimate the impact of potential secondary outbreaks at a community outside China. Simulations using stochastic SEIR model was conducted, assuming one patient was imported to a community. Among 45 possible scenarios we prepared, the worst scenario resulted in total number of persons recovered or removed to be 997 (95% CrI 990-1,000) at day 100 and maximum number of symptomatic infectious patients per day of 335 (95% CrI 232-478). Calculated mean basic reproductive number (R0) was 6.5 (Interquartile range, IQR 5.6-7.2). However, with good case scenarios with different parameter led to no secondary case. Altering parameters, especially time to hospital visit could change the impact of secondary outbreak. With this multiple scenarios with different parameters, healthcare professionals might be able to prepare for this viral infection better.
ARTICLE | doi:10.20944/preprints202007.0599.v1
Subject: Social Sciences, Other Keywords: crisis self-efficacy; work commitment; education workers; public schools; COVID-19 pandemic
Online: 24 July 2020 (14:47:56 CEST)
COVID-19 pandemic has affected the public educational sectors in terms of adjustment in educational modalities of instructional delivery, school operations, and policies. With this emerging paradigm shift, teachers' crisis self-efficacy and work commitment are relevant for research. This study's main objective was to determine the significant influence of crisis self-efficacy on the work commitment of public school teachers in Region XI (Davao Region), Philippines, during the COVID-19 pandemic. The sample consisted of 1,340 public school teachers across the Davao Region. The researchers collected the data through adapted questionnaires contextualized to the local setting and administered through online Google forms with appended consent. Mean, standard deviation, Pearson r, and regression analysis were used to analyze data. Results revealed that crisis self-efficacy significantly influences the work commitment of public school teachers during the COVID-19 pandemic. Uncertainty management during this crisis, in particular, best predicts teachers’ work commitment. Data also showed a high level of crisis self-efficacy in terms of action, preventive, achievement and uncertainty management, and high level of teachers’ work commitment in terms of commitment to school, commitment to students, commitment to teaching, and commitment to profession. Correlation results also showed a link between crisis self-efficacy and the work commitment of teachers amid pandemic. Finally, the study concluded with practical recommendations and directions for future research.
BRIEF REPORT | doi:10.20944/preprints202002.0242.v2
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: COVID-19; molecular docking; HIV protease inhibitor; nucleotide analogues
Online: 29 February 2020 (12:43:40 CET)
The outbreak of novel coronavirus (COVID-19) infections in 2019 is in dire need of finding potential therapeutic agents. In this study, we used molecular docking to repurpose HIV protease inhibitors and nucleoside analogues for COVID-19, with evaluations based on docking scores calculated by AutoDock Vina and RosettaCommons. Our results suggest that Indinavir and Remdesivir possess the best docking scores, and comparison of the docking sites of the two drugs reveal a near perfect dock in the overlapping region of the protein pockets. After further investigation of the functional regions inferred from the proteins of SARS coronavirus, we discovered that Indinavir does not dock on any active sites of the protease, which may give rise to concern in regards to the efficacy of Indinavir. On the other hand, the docking site of Remdesivir is not compatible with any known functional regions, including template binding motifs, polymerization motifs and nucleoside triphosphate (NTP) binding motifs. However, when we tested the active form (CHEMBL2016761) of Remdesivir, the docking site revealed a perfect dock in the overlapping region of the NTP binding motif. This result suggests that Remdesivir could be a potential therapeutic agent. Clinical trials still must be done in order to confirm the curative effect of these drugs.
REVIEW | doi:10.20944/preprints201807.0198.v1
Subject: Biology, Ecology Keywords: Yabello rangeland; degradation; rehabilitation techniques; encroachment
Online: 11 July 2018 (11:56:31 CEST)
Background: Rangeland degradation means that a reduction both in rank and status of general floral/ fauna composition, energy flow and biomass of a certain ecosystem. Objective: The review was conducted to assess rangeland degradation, cause and its impact on local livelihood in Yabello district and also suggests appropriate methods used to rehabilitate it. Methods: The data and literatures were collected from different both domestic and abroad researcher research result reviewed and internet sources. The research paper review mainly addresses concepts of rangeland degradation, major causes in tropics and Ethiopia particularly in Yabello rangelands, impacts of rangeland degradation, principles of rangeland restoration and common restoration techniques.Result: Based on those research papers and the current fact situations the major drivers leading to rangeland degradation includes climate change, overgrazing, bush encroachment, both human and livestock population pressure, drought, and government policy . Of all bush encroachment is becoming the major threat to Yabello rangelands. And this led to decline in rangeland condition, water potential, soil status, and animal performance, livestock holding at the household level and community become destitute and in the long run poverty. In spite of these impacts, the action of restoration techniques in the area is highly insufficient. Conclusion: Generally in order to address rangeland degradation problems, there is a strong need to coordination between the local community and the scientific community for sustainable land management trough post management techniques by applying reseeding technology.
ARTICLE | doi:10.20944/preprints202003.0455.v1
Online: 31 March 2020 (10:16:13 CEST)
Background: COVID-19, a member of corona virus family is spreading its tentacles across the world due to lack of drugs at present. Associated with its infection are cough, fever and respiratory problems causes more than 15% mortality worldwide. It is caused by a positive, single stranded RNA virus from the enveloped coronaviruse family. However, the main viral proteinase (Mpro/3CLpro) has recently been regarded as a suitable target for drug design against SARS infection due to its vital role in polyproteins processing necessary for coronavirus reproduction.Objectives: The present in silico study was designed to evaluate the effect of Eucalyptol (1,8 cineole), a essential oil component from eucalyptus oil, on Mpro by docking study.Methods: In the present study, molecular docking studies were conducted by using 1-click dock and swiss dock tools. Protein interaction mode was calculated by Protein Interactions Calculator.Results: The calculated parameters such as RMSD, binding energy, and binding site similarity indicated effective binding of eucalyptol to COVID-19 proteinase. Active site prediction further validated the role of active site residues in ligand binding. PIC results indicated that, Mpro/eucalyptol complexes forms hydrophobic interactions, hydrogen bond interactions and strong ionic interactions.Conclusions: Therefore, eucalyptol may represent potential treatment potential to act as COVID-19 Mpro inhibitor. However, further research is necessary to investigate their potential medicinal use.
REVIEW | doi:10.20944/preprints202005.0003.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Anti-platelets; Anti-rheumatic drugs; Bisphosphonates; Oral anticoagulants; Oral contraceptives; Vitamin K antagonist
Online: 2 May 2020 (11:50:24 CEST)
More than 15,000 prescriptions and over the counter drugs are available according to the US Food and Drug Administration website. Moreover, several herbal medicines and dietary supplements are readily available to add to the list of possible drugs, which can potentially cause adverse drug interactions. These are a pressing concern for all as they can interfere with many dental procedures. Additionally, the number of geriatric patients seen in routine dental practice has increased over time. This implies that there are more patients with multiple diseases and health conditions like hypertension, diabetes, problems associated with the cardiovascular, renal and gastrointestinal systems, arthritis, osteoporosis, etc. All these require patients to be on certain medications. Furthermore, advancement in the dental field has led to more complex dental procedures (implants, grafts) being carried out in a general dental practice. These advanced and slightly more invasive treatments require the use of certain drugs before, during and after the treatment like local anesthetics, vasoconstrictors, anxiolytics, analgesics and antibiotics. All of these can possibly interact with medications a patient is already taking and can also interfere with the current dental treatment and create complications. This article aims to provide necessary information about commonly encountered systemic diseases and associated treating medications, their mechanism of action, possible complications and their management. The classes of drugs discussed include anti-platelet agents, vitamin K antagonists, novel oral anticoagulants, bisphosphonates, disease-modifying anti-rheumatic drugs and oral contraceptives.
ARTICLE | doi:10.20944/preprints202005.0057.v2
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; treatment; drug; survival; antiviral; hydroxychloroquine
Online: 9 May 2020 (04:45:37 CEST)
Background: Although no specific treatment for COVID 19 has been proven effective yet, some drugs with in vitro potential against SARS-CoV-2 virus have been proposed for clinical use. Hydroxychloroquine has in vitro anti-viral and immunomodulatory activity, but there is no current clinical evidence of its effectiveness on the outcome of the disease. Methods: We enrolled all 18-85 years old inpatients from Central Defense Hospital, Madrid, Spain, who were hospitalised due to COVID-19 and had a definitive outcome (either dead or discharged). We used a statistical survival analysis. Results: We analysed 220 medical records. 166 patients met the inclusion criteria. 48,8 % of patients not treated with HCQ died, versus 22% in the group of hydroxychloroquine (p=0,002). According to clinical picture at admission, hydroxychloroquine increased the mean cumulative survival in all groups from 1,4 to 1,8 times. This difference was statistically significant in the mild group. Conclusions: in a cohort of 166 patients between 18 to 85 years hospitalised with COVID-19, hydroxychloroquine treatment with an initial loading dose of 800mg improved patient survival when admitted in early stages of the disease. There was a non-statistically significant trend towards survival in all groups, which will need to be clarified in subsequent studies.
ARTICLE | doi:10.20944/preprints201607.0010.v1
Subject: Social Sciences, Finance Keywords: Stock Beta, Endogenous Structural Breaks, Time Horizon
Online: 8 July 2016 (08:35:15 CEST)
The stock beta coefficient literature extensively discusses the proper methods for the estimation of beta as well as its use in asset valuation. However, there are relatively few references with respect to the appropriate time horizon that investors should utilize when evaluating the risk-return relationship of a stock. We examine the appropriate time horizon for beta estimation differentiating our results by sector according to the Industry Classification Benchmark. We employ data from the NYSE and we estimate varying lengths of beta employing data from 30 to 250 trading days. The constructed beta series is then examined for the presence of breaks using the endogenous structural break literature. Results show evidence against the use of betas that employ more than 90 trading days of data provisional to the sector under study.
ARTICLE | doi:10.20944/preprints201708.0033.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: petroleum sludge; characterization; total organic carbon; metal concentration
Online: 8 August 2017 (13:24:39 CEST)
Thermal plasma technique is becoming prominent in the treatment of variety of waste ranging from municipal solid waste, incinerator residue, hospital waste, electronics waste and industrial sludge. Application of the new treatment technology to petroleum sludge requires information on the nature and characteristics of the sludge that will be use to optimize the treatment system. In this investigation, petroleum sludge obtained from Petronas Melaka was characterized for its physical and chemical features. Proximate and ultimate analysis as well as determination of elemental composition were carried out. The sludge was found to contain high moisture (78.91%), low ash (5.06%), low volatiles (5.52%) and high fixed carbon (10.51%). The sludge has a TOC of 54.48% and HHV of 23.599MJ/kg. Despite the high moisture content, the higher heating value (HHV) is high when compared to literature values. The high value of HHV may be associated with the high fixed carbon, low ash content and high value of TOC. The apparent density of the sludge is slightly lower. Fourteen heavy metals are detected in significant quantities. Proper waste management that will safely dispose the sludge is required. The waste disposal technique should take into cognizant the possibility of leaching of heavy metals into ground water on one hand and the gasification of lighter ones on the other.
REVIEW | doi:10.20944/preprints202004.0103.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Coronavirus; SARS-CoV-2; Medical Laboratory; Resource-limited setting, Good Laboratory Practice (GLP)
Online: 7 April 2020 (12:11:35 CEST)
The 2019 Coronavirus pandemic which was initially referred to as 2019-nCoV, was first identified in Wuhan, China. Early response from the Chinese government included quarantine of infected persons, isolation and total lockdown of Wuhan province to prevent further spread. With the spread of the disease across national borders and declaration of the disease as a global pandemic, there has been a robust response by the international community to contain this deadly virus and prevent its further spread worldwide. Africa is not left out of this rampaging pandemic with documented cases in over 40 countries and still rising. Although extensive studies have been carried out on the novel SARS-CoV-2 on its pathogenesis, mode of infection and virulence but much is still unknown. However, potentially infectious samples are received routinely in the medical laboratory for analysis. This technical note reviews good laboratory practice (GLP) and processes across the different specialities of Medical Laboratory practice that should minimize the risk of infection to laboratory staff especially in resource-limited settings.
ARTICLE | doi:10.20944/preprints201808.0062.v1
Subject: Social Sciences, Education Studies Keywords: africanization; transformation; education; reform; challenges; prospects
Online: 3 August 2018 (05:34:55 CEST)
Africanization of education was a major policy option in most countries in Africa upon the attainment of independence. This is because of the perceived negative effects of colonial education. The paper is an empirical sources study which discusses Africanization as an epistemicide and analyses efforts by some African states to Africanize their educational systems. It concludes that while some countries embraced the idea and actually initiated policies to Africanize their educational systems, the general picture indicates that Africanization has not succeeded in most countries due to various challenges. Such challenges are identified and recommendations made which could be significant for the revamping of the policy.
ARTICLE | doi:10.20944/preprints201706.0029.v1
Subject: Keywords: teaching and learning ıssues in mathematics; social ıssues in mathematics education; cultural ıssues in mathematics education; political ıssues in mathematics education; technological ıssues in mathematics education
Online: 5 June 2017 (06:13:28 CEST)
In this paper, we discuss major issues of mathematics teaching and learning in Nepal. The issues coming from theories such as social and radical constructivism suggest that teachers are not trained to use such approach in teaching mathematics, and there is a lack of teaching aids and materials and technological tools. The issues related to social aspects are gender issues, language issues, social justice issues, and issues related to the achievement gap. The cultural issues are related to the diversity of language and ethnicity. The issues related to political aspects are equity and access, economic status, pedagogical choice, and professional organizations and unions. The issues related to technology include the technological skills, use of technology, and affordance. Finally, we suggest that all the stakeholders should pay attention to resolving these issues by improving the curriculum, training teachers, resourcing the classroom with locally made and new technological tools.
Subject: Social Sciences, Geography Keywords: circular economy; social ecology; consumerism; dialectical naturalism; mining
Online: 12 September 2016 (09:55:09 CEST)
The concept of a "circular economy" needs a more cogent theoretical anchor which will allow for transference of its goals and methods of attainment across cases. Tensions between ecological goals of this concept and the social implications of its implementation need to be addressed. This paper attempts to provide a theoretical framework for harnessing the strengths of a circular economy. Building on theories of social ecology which are predicated in Murray Bookchin's notion of "dialectical naturalism", the analysis presented here addresses some of the criticism of circular economic paradigms, such as their potential for stifling innovation or a neglect of human development challenges. A model for managing human "need" and "greed" within a circular economy framework is presented that also incorporates consumer choice and innovation. Planned obsolescence as a means of livelihood generation is also problematized with a view towards balancing durability of products on the one hand and ensuring throughput for manufacturing employment and innovation incentives on the other. Finally, the need for governance systems is considered to ensure that a planetary vision for a circular economy can be realized that efficiently harnesses local initiatives rather than an atomized and insular view of circularity.
ARTICLE | doi:10.20944/preprints201911.0393.v1
Subject: Earth Sciences, Geoinformatics Keywords: Sentinel-1; PolSAR; synthetic aperture radar; earth observation; SNAP
Online: 30 November 2019 (11:39:51 CET)
Sentinel-1 SAR data preprocessing is essential for several earth observation applications, including land cover classification, change detection, vegetation monitoring, urban growth, natural hazards, etc. The information can be extracted from the 2x2 covariance matrix [C2] of Sentinel-1 dual-pol (VV-VH) acquisitions. To generate the covariance matrix from Sentinel-1 single look complex (SLC) data, several preprocessing steps are required. The ESA SNAP S-1 toolbox can be used to preprocess the data to generate a [C2] matrix. The polarimetric analysis in respective application fields often starts with the covariance matrix. However, due to limited availability of Sentinel-1 SLC data preprocessing workflow standards for polarimetric applications in contemporary research methods, downstream applications unable to comply with these workflows directly. In this paper, we propose a couple of generic practices to preprocess Sentinel-1 SLC data in SNAP S-1 toolbox, which would be beneficial for the radar remote sensing user community.
REVIEW | doi:10.20944/preprints202006.0336.v1
Online: 28 June 2020 (10:07:58 CEST)
The outbreak of Corona Virus effected negatively on the world’s economy which has already touched the maximum sectors. Readymade garments sector has the large contribution in Bangladesh’s economy. For increasing the locked down period, it is hitting badly by stopping production and cancellation of orders with some issues. This paper will represent the brief scenario and impacts of garments sector in recent days and the economy status of Bangladesh for the pandemic. The study is based on secondary data, collected from different authentic journals and web portals etc. Bangladesh’s garments earnings mostly depended on export but on these days, the buyers are cancelling their orders and the factories are being failed to give payments to the worker, some are being shut down also. As the duration of locked down is increasing, there is a huge chance to get unemployed and Bangladesh can be faced an undisciplined condition in near future. BGMEA and BKMEA are taking necessary steps to support the worker. Ensuring health security, the authorities are trying to reopen the factories limitedly to meet up the immediate needs. The government has taken the situation on most priority and introduce some improvement packages to run the economy smoothly and reduce the losses of the country for the pandemic.
ARTICLE | doi:10.20944/preprints201908.0073.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: contextual keyword extraction; BERT; word embedding; LSTM; transformers; Deep Learning
Online: 6 August 2019 (09:17:36 CEST)
In this paper we propose a novel self-supervised approach of keywords and keyphrases retrieval and extraction by an end-to-end deep learning approach, which is trained by contextually self-labelled corpus. Our proposed approach is novel to use contextual and semantic features to extract the keywords and has outperformed the state of the art. Through the experiment the proposed approach has been proved to be better in both semantic meaning and quality than the existing popular algorithms of keyword extraction. In addition, we propose to use contextual features from bidirectional transformers to automatically label short-sentence corpus with keywords and keyphrases to build the ground truth. This process avoids the human time to label the keywords and do not need any prior knowledge. To the best of our knowledge, our published dataset in this paper is a fine domain-independent corpus of short sentences with labelled keywords and keyphrases in the NLP community.
ARTICLE | doi:10.20944/preprints201608.0159.v2
Subject: Social Sciences, Economics Keywords: public investment; domestic private investment; FDI; crowding out effect; economic growth
Online: 30 August 2016 (04:03:38 CEST)
This paper analyzes the causal effect between domestic private investment, public investment, foreign direct investment and economic growth in Tanzania during the 1970-2014 period. The modified neo-classical growth model is used to estimate the ieffect of investment on economic growth. Also, the economic growth models based on Phetsavong and Ichihashi (2012) , and Le and Suruga (2005) are used to estimate the crowding out effect of public investment on domestic private investment on one hand and foreign direct investment on the other hand. In the same way, the crowding out effect of foreign direct investment on domestic private investment is estimated. A correlation test is applied to check the correlation among independent variables, and the results show that there is very low correlation suggesting that multicollinearity is not a serious problem. Moreover, the diagnostic tests including RESET regression errors specification test, Breusch-Godfrey serial correlation LM test, Jacque-Bera-normality test and white heteroskedasticity test reveal that the model has no signs of misspecification and that, the residuals are serially uncorrelated, normally distributed and homoskedastic. Broadly, the empirical results show that the domestic private investment and foreign direct investment play an important role in economic growth in Tanzania. Besides, a revealed negative, albeit weak, association between public and private investment suggests that the positive effect of domestic private investment on economic growth becomes smaller when public investment-to-GDP ratio exceeds 8-10 percent. Similarly, foreign direct investment tends to marginally reduce the impact of domestic private investment on growth. These results suggest that public investment and foreign direct investment need to be considered carefully in order to avoid a reduced positive impact of domestic private investment on growth. Domestic saving may be promoted to encourage domestic investment for economic growth.
ARTICLE | doi:10.20944/preprints202104.0702.v1
Subject: Social Sciences, Accounting Keywords: COVID-19; vaccine acceptance; vaccine willingness; vaccine hesitancy; quantitative; online survey; Philippines
Online: 27 April 2021 (10:12:47 CEST)
With COVID-19 vaccines slowly being rolled out in many countries, it is important to understand the public’s acceptance of being vaccinated. This study aims to study the willingness and motivations among residents of the cities of Caloocan, Malabon, and Navotas, Philippines to be vaccinated against COVID-19. Based on an online survey of 137 respondents, who willingly participated in the study, 71% will take a COVID-19 vaccine if it becomes available, with similar rates among respondents from Caloocan (82%), Malabon (83 %), and Navotas (81%). If a vaccine is proven safe and effective, more respondents (82%) will take a COVID-19 vaccine. Furthermore, safety against COVID-19 as well as the safety and effectiveness of vaccines are the primary factors why respondents are willing or unwilling to get a vaccine. The results highlight the need for effective messaging that promotes COVID-19 vaccination, with emphasis on the safety and effectiveness of the vaccine, and its benefits to the public, especially that the vaccines that will be delivered in the country in the next few months are not the most preferred brands by the respondents.
HYPOTHESIS | doi:10.20944/preprints202003.0279.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: chloroquine; COVID-19; SARS-CoV2; antiviral; viral prophylaxis
Online: 17 March 2020 (15:57:38 CET)
The novel coronavirus 2019 (COVID-19) pandemic is rapidly advancing despite public health measures. Pharmaceutical prophylaxis is an established approach to potentially control infectious diseases and is one solution to the urgent public health challenge posed by COVID-19. Screening and development of new vaccines and antivirals is expensive and time consuming while the repositioning of available drugs should receive priority attention as well as international government and agency support. Here we propose an old drug chloroquine (CQ) to be urgently repositioned as an ideal antiviral prophylactic against COVID-19. CQ has ability to block viral attachment and entry to host cells. Its proven clinical efficacy against a variety of viruses including COVID-19 and its current deployment in COVID-19 therapeutic trials strengthens its potential candidacy as a prophylactic. Furthermore, CQ has a long safety record, is inexpensive and widely available. Here we reviewed CQ's antiviral mechanisms, its laboratory efficacy activity against COVID-19, as well as CQ's pharmacokinetics in its established use against malaria and autoimmune diseases to recommend safe and potentially efficacious dose regimens for protection against COVID-19: a pre-exposure prophylaxis of 250-500mg daily and post-exposure prophylaxis at 8mg/kg/day for 3 days. We recommend further urgent research on CQ for COVID-19 prevention and urge that the above regimens be investigated in parallel with mass deployment by relevant agencies in attempts to contain the pandemic without unnecessary regulatory delays as benefits far outweigh risks or costs.
Subject: Engineering, Automotive Engineering Keywords: lidar, ladar, time of flight, 3D imaging, point cloud, MEMS, scanners, photodetectors, lasers, autonomous vehicles, self-driving car
Online: 8 August 2019 (12:23:48 CEST)
Imaging lidars are one of the hottest topics in the optronics industry. The need to sense the surroundings of every autonomous vehicle has pushed forward a career to decide the final solution to be implemented. The diversity of state-of-the art approaches to the solution brings, however, a large uncertainty towards such decision. This results often in contradictory claims from different manufacturers and developers. Within this paper we intend to provide an introductory overview of the technology linked to imaging lidars for autonomous vehicles. We start with the main single-point measurement principles, and then present the different imaging strategies implemented 8 in the different solutions. An overview of the main components most frequently used in practice is also presented. Finally, a brief section on pending issues for lidar development has been included, 10 in order to discuss some of the problems which still need to be solved before an efficient final implementation.Beyond this introduction, the reader is provided with a detailed bibliography containing both relevant books and state of the art papers.
REVIEW | doi:10.20944/preprints201702.0045.v1
Online: 14 February 2017 (03:08:37 CET)
Biodiversity has become an issue of global anxiety over the past decades due to its rapid decline worldwide. Bangladesh as one of the most densely populated countries in the world is no more exception. The country, although, was once very rich in biodiversity, during the last few decades as a consequence of the rapid reduction in forest area, urbanisation, habitat modification, unsustainable natural resources use and collection and overall climate change it has decreased alarmingly. Of late, the government, as a signatory of various regional and international conservation treaties, has taken various initiatives to improve country’s dwindling biodiversity. This paper reviews the present situation of biodiversity in Bangladesh, management trends and major causes of biodiversity loss. A separate statutory body is fundamental to ensure conservation, sustainable use and equitable sharing of benefits arisen from biodiversity in the country.
ARTICLE | doi:10.20944/preprints202102.0388.v1
Subject: Social Sciences, Accounting Keywords: production; calamansi; Philippine Lime; development plan; Nueva Ecija; economics
Online: 17 February 2021 (12:29:09 CET)
This study examined the economics of Philippine Lime or Calamansi production in selected Cities and Municipalities in Nueva Ecija, Philippines. The study was conducted within the rural farming households' framework, which constitutes the Philippine agricultural sector's backbone, producing about 5.8 percent of the total national agricultural output with the Central Luzon area, including the portion of the locale of the study. Using quota sampling, data collected from 50 selected calamansi grower- farmers from top 5 producing area in Nueva Ecija, the study measured the profitability of and the production efficiency of calamansi production in the area. Using a formal interview schedule, primary data was obtained from the sampled farming households. The study revealed that the typical calamansi farmer in the area as reflected in the instrument, thirty-two (32) or 64% which covers the majority of the respondents claimed that they fully owned the land they cultivated. Calamansi yield depends on its age as well. Fertilizer was found to harm output. Majority of them shared the same production and post–production practices, though a slight difference in terms of labor cost was observed. There were some who were already in the industry for quite a long time and learned other farming techniques and practices different from the conventional and were proven effective. For better efficiency, the land area cultivated, the farmers' educational status, accessibility to credit facility, and development of the rural areas and farmers' contact with the extension agents are some of the key issues to address. The local government in cities and municipalities may engage in an intensive campaign in encouraging capitalists to form cooperatives, processing and manufacturing houses to produce calamansi juice and other valuable products out of the calamansi fruit.
REVIEW | doi:10.20944/preprints202004.0548.v1
Subject: Keywords: COVID-19; coronavirus; SARS-CoV-2; aging; immunosenescence; inflammaging; inflammation; cytokine storm; epigenetics; biological clock; sirtuin; glycome
Online: 30 April 2020 (22:38:53 CEST)
The severity and outcome of coronavirus disease 2019 (COVID-19) largely depends on a patient’s age. Over 80% of hospitalizations are of those over 65 years of age with a 23-fold greater risk of death. In the clinic, COVID-19 patients most commonly present with fever, cough and dyspnea. Particularly in those over 65, it can progress to pneumonia, lung consolidation, cytokine release syndrome, endotheliitis, coagulopathy, multiple organ failure and death. Comorbidities such as cardiovascular disease, diabetes, obesity and hypertension increase the chances of fatal disease, but they alone do not explain the variability in COVID-19 symptoms. Here, we present the molecular differences between the young, middle-aged and elderly that may determine whether COVID-19 is a mild or life-threatening illness. We also discuss several biological age clocks that could be used in conjunction with genetic tests to identify both the mechanisms of the disease and individuals most at risk. Finally, based on these mechanisms, we discuss treatments that could increase survival in the elderly, not simply by inhibiting the virus, but by restoring patients’ ability to clear the infection.
ARTICLE | doi:10.20944/preprints201801.0010.v1
Online: 2 January 2018 (10:10:51 CET)
Although the phenomenon of serial killers has received great attention from media, governments, and public, very little information is known about them and very few theories are presented by researchers specifically their definition and motives for killing. Through cross tabulation analysis of top ninety-eight serial killers, this present study poses six questions that investigate the correlations between, offender's gender, offender's level of education, time span of killing, killing severity, number of victims, killer's type of abuse, motives for killing, and victim's profile. Findings show that males kill more than females and for longer time, less educated serial killers kill more horribly, female serial killers consider their family members easy target, and finally males kill most for enjoyment and sex and females kill for financial gains.
ARTICLE | doi:10.20944/preprints202007.0486.v2
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: knowledge representation; curation; biocuration; semantics; systems biology; ontology; user interface; VSM
Online: 29 July 2020 (17:29:20 CEST)
Scientific progress is increasingly dependent on knowledge in computation-ready forms. In the life sciences, among others, many scientists therefore extract and structure knowledge from the literature. In a process called manual curation, they enter knowledge into spreadsheets, or into databases where it serves their and many others' research. Valuable as these curation efforts are, the range and detail of what can practically be captured and shared remains limited, because of the constraints of current curation tools. Many important contextual aspects of observations described in literature simply do not fit in the form defined by these tools, and thus cannot be captured. Here we present the design of an easy-to-use, general-purpose method and interface, that enables the precise semantic capture of virtually unlimited types of information and details, using only a minimal set of building blocks. Scientists from any discipline can use this to convert any complex knowledge into a form that is easily readable and meaningful for both humans and computers. The method VSM forms a universal and high-level language for encoding ideas, and for interacting with digital knowledge.
REVIEW | doi:10.20944/preprints202003.0001.v2
Subject: Medicine & Pharmacology, Other Keywords: emerging coronavirus; 2019-nCoV; SARS-CoV-2; COVID-19; diagnosis; vaccines; therapy; one health
Online: 13 April 2020 (02:29:00 CEST)
In the past decades, several new diseases have emerged in new geographical areas, with pathogens including Ebola, Zika, Nipah, and coronaviruses (CoVs). Recently, a new type of viral infection has emerged in Wuhan City, China, and initial genomic sequencing data of this virus does not match with previously sequenced CoVs, suggesting a novel CoV strain (2019-nCoV), which has now been termed as severe acute respiratory syndrome CoV-2 (SARS-CoV-2). Although Coronavirus disease 2019 (COVID-19) is suspected to originate from an animal host (zoonotic origin) followed by human-to-human transmission, the possibility of other routes such as food-borne transmission should not be ruled out. Compared to diseases caused by previously known human CoVs, COVID-19 shows less severe pathogenesis but higher transmission competence, as is evident from the continuously increasing number of confirmed cases globally. Compared to other emerging viruses such as Ebola virus, avian H7N9, SARS-CoV, or MERS-CoV, SARS-CoV-2 has shown relatively low pathogenicity and moderate transmissibility. Codon usage studies suggest that this novel virus may have been transferred from an animal source such as bats. Early diagnosis by real-time PCR and next-generation sequencing has facilitated the identification of the pathogen at an early stage. Since, no antiviral drug or vaccine exists to treat or prevent SARS-CoV-2, potential therapeutic strategies that are currently being evaluated predominantly stem from previous experience with treating SARS-CoV, MERS-CoV, and other emerging viral diseases. In this review, we address epidemiological, diagnostic, clinical, and therapeutic aspects, including perspectives of vaccines and preventive measures that have already been globally recommended.
REVIEW | doi:10.20944/preprints202007.0027.v1
Subject: Arts & Humanities, General Humanities Keywords: COVID-19; Deadly disease; Education; Resolution; Africa; Sub-Sahara
Online: 3 July 2020 (08:57:38 CEST)
The eruption of the COVID-19 pandemic has affected every sphere of life and may forever change how we have always lived and conducted our businesses, and no one can resist the wind of change that is blowing. Of all the sectors of governance, the educational sector, particularly at the tertiary level, appears to have been most greatly affected and therefore requires a more pragmatic approach to resolution. As of 29th June, Sub-Sahara Africa has reported 382,190 cases of COVID-19. In rejoinder to the virus epidemic, several Sub Sahara African governments implement the resolution to slam learning institutions to enclose the infection. Consequently, advanced schooling institutions obliged to reorganize their loom, becoming more digitally become forward, and changing to online platforms.
ARTICLE | doi:10.20944/preprints202007.0112.v1
Online: 7 July 2020 (08:11:24 CEST)
Soft drinks exist in various forms and brands and are marketed by different brewery industries across the country. Nigeria been an underdeveloped country were aforesaid health problems are common, people tends to consume them lots believing it gives more energy. This study was therefore set to assess the sugar content from different soft drinks sold in Nigeria. Ten (10) soft drinks registered and licensed in Nigeria by their respective companies were purchased from a supermarket in Ihumudumu environment of Ekpoma, Nigeria. The sugar contents were assessed using standard methods. Result showed significant differences (p<0.05) in ranges of 0.36g/100ml (Limca) to 3.88g/100ml (Teem Bitter Lemon). Conclusively, the sugar contents were all below recommended value and it can be consumed by those who need low sugar in the body.
ARTICLE | doi:10.20944/preprints202011.0457.v3
Subject: Engineering, Automotive Engineering Keywords: Timoshenko beam; moment shear force curvature relationship; closed-form solutions; non-uniform heating; stability; second-order element stiffness matrix; elastic Winkler foundation
Online: 15 July 2021 (10:30:53 CEST)
This paper presents an exact solution to the Timoshenko beam theory (TBT) for first-order analysis, second-order analysis, and stability. The TBT covers cases associated with small deflections based on shear deformation considerations, whereas the Euler–Bernoulli beam theory (EBBT) neglects shear deformations. Thus, the Euler–Bernoulli beam is a special case of the Timoshenko beam. The moment-curvature relationship is one of the governing equations of the EBBT, and closed-form expressions of efforts and deformations are available in the literature. However, neither an equivalent to the moment-curvature relationship of EBBT nor closed-form expressions of efforts and deformations can be found in the TBT. In this paper, a moment-shear force-curvature relationship, the equivalent in TBT of the moment-curvature relationship of EBBT, was presented. Based on this relationship, first-order and second-order analyses were conducted, and closed-form expressions of efforts and deformations were derived for various load cases. Furthermore, beam stability was analyzed and buckling loads were calculated. Finally, first-order and second-order element stiffness matrices were determined.
ARTICLE | doi:10.20944/preprints201704.0124.v1
Online: 19 April 2017 (11:53:38 CEST)
A fluid flowing over an object has a tendency to drag the object along it’s flow direction. An object passing through a fluid which is stationary there is a tendency to slow the object down. For a stationary object in a fluid which is flowing there is a tendency to move the object in the fluid flowing direction .These tendencies of flowing fluid is known as drag. While moving through air airplanes also subjected to several drags. Airplanes subjected to pressure drag or form drag due to flow separation which is based on the pressure difference between the upstream and downstream surfaces of the object. Airplanes also subjected to Skin friction drag which results from the viscous shear of the fluid flowing over the object surface. In order to overcome these drags airplane wings cross section airfoils are designed very carefully. National Advisory Committee for Aeronautics, or NACA, developed and tested "families" of airfoils. Some of the most successful of these were the NACA four-digit and five-digit series. The necessary coordinates for designing NACA airfoil profiles are available in online. UIUC also provide coordinates for designing NACA airfoil profiles. But the present work describes the way of designing NACA four digit airfoils without taking any coordinates from available sources like google or any other search engines. Using C programming with the help of NACA provided equations a generalized source code is designed .Which will provide coordinates for designing any NACA four digit airfoil profiles .With the help of this obtained profile the wing model is also constructed using solid works. Using solid works model the real model was constructed using wood. The chord of regular surface airfoil is 21 cm and the span is also 21 cm. The airfoil profile taken for the model construction is NACA-4415 which is a four digit cambered airfoil.The present work also show some figures of an airfoil by applying certain surface modifications in form of dimples.
REVIEW | doi:10.20944/preprints202003.0346.v1
Subject: Medicine & Pharmacology, Other Keywords: COVID-19; nCoV 19; oxidative stress; PARP; PARG; TRPM2
Online: 23 March 2020 (07:40:50 CET)
The emerging new Coronaviridae member, nCoV 19, outbreak announced a pandemic by WHO with an increased morbidity and mortality rate worldwide. nCoV 19 known as the third highly pathogen coronavirus in the human population after the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), the nCoV 19. The renin-angiotensin (RAS) signaling pathway, oxidative stress and cell death, cytokines storm and endothelial dysfunction are four major pathways involved in the pathogenesis of nCoV 19. Acute respiratory distress syndrome (ARDS) generally develops with a massive oxidative/nitrosative stress following virus entry and RAS activation. The DNA damage subsequent to oxidative burst activates poly-ADP ribose polymerase-1 (PARP-1), viral macrodomain (NSP3) poly (ADP-ribose) glycohydrolase (PARG) and transient receptor potential channel, melastatin 2 (TRPM2) in a sequential manner ultimately leading to apoptosis and necrosis due to NAD and ATP depletion. Regarding the molecular mechanisms involved in nCoV 19 pathogenesis, angiotensin II receptor blockers and/or PARP, PARG and TRPM2 blockers could be engaged as therapeutic candidates for inhibition of RAS and quenching oxidative stress, respectively. In this review, the molecular aspects of nCoV 19 pathogenesis would be studied precisely and possible therapeutic targets would be proposed. It is recommended to evaluate the proposed drugs and supplements via registered clinical trials along with conventional guideline-based multi-drug regimen.
REVIEW | doi:10.20944/preprints201810.0061.v1
Subject: Physical Sciences, Fluids & Plasmas Keywords: Plasma Generation Techniques, Applications of Plasma; Fusion technology; Plasma ion implantation and Deposition.
Online: 3 October 2018 (15:54:34 CEST)
Plasma being the fourth and most abundant form of matter extensively exists in the universe in the inter-galactic regions. It provides an electrically neutral medium of unbound negative and positive charged particles, which has been produced by subjecting air and various other gaseous mixtures to strengthen the electromagnetic field and by heating compressed air or inert gasses for creating negative and positive charged particles known as ions. Nowadays, many researchers are paying attention to the formation of artificial Plasma and its potential benefits for mankind. The literature is sparsely populated with the applications of Plasma. This paper presents specific methods of generation and applications of Plasma, which benefits humankind in various fields, such as in electrical, mechanical, chemical and medical fields. These applications include hydrogen production from alcohol, copper bonding, semiconductor processing, surface treatment, Plasma polymerization, coating, Plasma display panels, antenna beam forming, nanotechnology, Plasma Torch, Plasma pencils, low-current non-thermal Plasmatron, treatment of prostate cancer, Plasma source ion implantation, cutting by Plasma, Plasma etching, pollution control, neutralization of liquid radioactive waste, etc. Resultantly, worth of Plasma technology in the medical industry is increasing exponentially that is closing the gap between its benefits and cost of equipment used for generating and controlling it.
ARTICLE | doi:10.20944/preprints201905.0056.v1
Subject: Life Sciences, Other Keywords: phylogenetic inference; maximum likelihood; parallel processing; HPC
Online: 6 May 2019 (11:12:20 CEST)
RAxML-NG is a new phylogentic inference tool that replaces the widely-used RAxML and ExaMLtree inference codes. Compared to its predecessors, RAxML-NG offers improvements in accur-acy, flexibility, speed, scalability, and user-friendliness. In this chapter, we provide practicalrecommendations for the most common use cases of RAxML-NG: tree inference, branch supportestimation via non-parametric bootstrapping, and parameter optimization on a fixed tree topo-logy. We also describe best practices for achieving optimal performance with RAxML-NG, inparticular, with respect to parallel tree inferences on computer clusters and supercomputers. AsRAxML-NG is continuously updated, the most up-to-date version of the tutorial described inthis chapter is available online at: https://cme.h-its.org/exelixis/raxml-ng/tutorial .
ARTICLE | doi:10.20944/preprints202006.0130.v2
Subject: Medicine & Pharmacology, Veterinary Medicine Keywords: academic performance; COVID-19; veterinary; online learning
Online: 21 August 2020 (02:25:37 CEST)
Many universities and colleges worldwide suspended classroom teaching due to the novel coronavirus pandemic and switched to online teaching. The current cross-sectional study was carried out to analyze the impact of lockdown due to coronavirus disease 2019 (COVID-19) pandemic on the academic performance of veterinary medical students and researchers. Veterinary medical students and researchers were invited to answer an online google form questionnaire. A total of 1398 participants were from 92 different countries answered the questionnaire with response rate of 94.52%. The data showed that COVID-19 pandemic lockdown affected the academic performance of most participants (96.7%) with varying degrees. The mean evaluation scores for the online education in general was 5.06 ± 2.43 while that for the practical parts was 3.62± 2.56. Although online education provides an opportunity for self-study. The main challenge online education faces in veterinary medical science is how to give practical lessons. Since most of the subjects are practical; therefore, it is not easy to learn it online. Students think that it is difficult to fulfill the veterinary competencies only with online education system. Online education can be improved by making it more interactive, showing medical procedures in real situations, giving concise information, and providing 3D virtual tools to mimic the real situation.
ARTICLE | doi:10.20944/preprints201607.0093.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: Non-volatile Memories; NAND Flash Memories; Storage Memories
Online: 29 July 2016 (13:40:38 CEST)
This paper presents an upcoming nonvolatile memories (NVM) overview. Non-volatile memory devices are electrically programmable and erasable to store charge in a location within the device and to retain that charge when voltage supply from the device is disconnected. The non-volatile memory is typically a semiconductor memory comprising thousands of individual transistors configured on a substrate to form a matrix of rows and columns of memory cells. Non-volatile memories are used in digital computing devices for the storage of data. In this paper we have given introduction including a brief survey on upcoming NVM's such as FeRAM, MRAM, CBRAM, PRAM, SONOS, RRAM, Racetrack memory and NRAM. In future Non-volatile memory may eliminate the need for comparatively slow forms of secondary storage systems, which include hard disks.
ARTICLE | doi:10.20944/preprints201803.0122.v1
Subject: Engineering, Energy & Fuel Technology Keywords: electric vehicle; Nissan Leaf; lithium-ion battery; capacity loss; battery degradation
Online: 15 March 2018 (07:19:52 CET)
Analysis of 1382 measures of battery State of Health (SoH) from 283 Nissan Leafs (“Leaf/s”), manufactured between 2011 and 2017, has detected a faster rate of decline in this measure of energy-holding capacity for 30 kWh variants. At two years of age, the mean rate of decline of SoH of 30 kWh Leafs was 9.9% per annum (95% uncertainty interval of 8.7% to 11.1%; n = 82). This was around three times the rate of decline of 24 kWh Leafs which at two years averaged 3.1% per annum (95% uncertainty interval of 2.9% to 3.3%; n = 201). For both variants there was evidence for an increasing rate of decline as they aged, although this was much more pronounced in the 30 kWh Leafs. Higher use of rapid DC charging was associated with a small decrease in SoH. Additionally, while 24 kWh cars with greater distances travelled showed a higher SoH, in 30 kWh cars there was a reduction in SoH observed in cars that had travelled further. The 30 kWh Leafs sourced from United Kingdom showed slower initial decline than those from Japan, but the rate of decline was similar at two years of age. Improvements in the battery health diagnostics, continuous monitoring of battery temperatures and state of charge, and verification of a fundamental model of battery health are needed before causes and remedies for the observed decline can be pinpointed. If the high rate of decline in battery capacity that we observed in the first 2.3 years of a 30 kWh Leaf’s lifetime were to continue, the financial and environmental benefits of this model may be significantly eroded. Despite 30 kWh Leafs accounting for only 14% of all light battery electric vehicles registered for use on New Zealand roads at the end of February 2018, there is also the potential for the relatively poor performance of this specific model to undermine electric vehicle uptake more generally unless remedies can be found.
Subject: Life Sciences, Virology Keywords: SARS-CoV-2; Quinine; Hydroxy-Chloroquine; Chloroquine; COVID-19; antiviral
Online: 6 July 2020 (09:19:06 CEST)
Since there is no vaccine or regulatory approved therapy available for treatment of SARS-CoV-2 infection, the medical need to prevent the transition of a mild into the severe COVID-19 stage of infection is of outmost importance. Among several drug candidates, Chloroquine (CQN) and Hydroxy-Chloroquine (H-CQN) have been tested most intensively. However, the therapeutic effect of H-CQN and CQN has been discussed controversially in the light of severe side effects. Originally, H-CQN descended from the natural substance Quinine, a medicinal product used since the Middle Ages and is now regulatory approved for various indications. We hypothesized that Quinine also exerts anti-SARS-CoV-2 activity. First, virus production in Vero B4 cells was analyzed by Western blot, showing that Quinine exerts antiviral activity against SARS-CoV-2 that at 10 µM was even stronger than that of H-CQN or CQN. Second, fluorescence end-point and time lapse analysis of SARS-CoV-2-mNeonGreen-infected Caco-2 cells could confirm a similar antiviral effect of Quinine in a human-derived cell line. Thereby, our in vitro studies revealed, that the antiviral effect appears to be specific, since in Vero cells Quinine impacted cell viability at approximately 50-fold higher concentration, while the therapeutic window of H-CQN and CQN was approximately 10-fold lower. In Caco-2 cells no toxic effect was observed while complete block of infection occurred between 50 and 100 µM at high MOIs. In conclusion, our data indicate that Quinine would have the potential of a well tolerable and widely used treatment option for SARS-CoV-2 infections, with a predictable and significantly better toxicological profile when compared to H-CQN or CQN.
ARTICLE | doi:10.20944/preprints201710.0194.v1
Subject: Chemistry, Medicinal Chemistry Keywords: Africa; Terminalia brownii; antifungal extracts; Aspergillus, Nattrassia, Fusarium; triterpenoids; flavonoids; ellagitannins; stilbenes
Online: 31 October 2017 (09:54:35 CET)
Decoctions, macerations and fumigations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as pesticides on field crops and in traditional granaries in Sudan. In addition, T. brownii is commonly used for protecting wooden houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts of various polarities from the stem wood and bark were screened for their growth inhibitory effects against filamentous fungi commonly causing fruit, vegetable and grain decay, as well as infections in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best antifungal activities, with MIC values of 250 µg/ml against Nattrassia mangiferae and Fusarium verticillioides, and 500 µg/ml against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and were slightly more active than the ethyl acetate extracts against Nattrassia mangiferae. Thin layer chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem bark and wood were found to have a similar qualitative composition of polyphenols and triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis- (3) and trans- (4) resveratrol-3-O-β-galloylglucoside, were identified for the first time in T. brownii. Moreover, methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), naringenin-4`-methoxy-7-pyranoside (7), 5,6-dihydroxy-3`,4`,7-tri-methoxy flavone (12), gallagic acid dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) were characterized. Our results justify the traditional uses of macerations and decoctions of T. brownii stem wood and bark for crop and wood protection and demonstrate that standardized extracts could have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. Likewise, our results justify the traditional uses of these preparations for the treatment of skin infections caused by filamentous fungi.
Online: 27 January 2021 (15:08:12 CET)
To date, uncertainty remains about how long the protective immune responses against SARS-CoV-2 persists and reports of suspected reinfection began to be described in recovered patients months after the first episode. Viral evolution may favor reinfections, and the recently described spike mutations, particularly in the receptor binding domain (RBD) in SARS-CoV-2 lineages circulating in the UK, South Africa, and most recently in Brazil, have raised concern on their potential impact in infectivity, immune escape and reinfection. We report a case of reinfection from distinct SARS-CoV-2 lineages presenting the E484K mutation in Brazil, a variant associated with escape from neutralizing antibodies.
REVIEW | doi:10.20944/preprints201907.0330.v1
Subject: Biology, Plant Sciences Keywords: incompatibility; male sterility; mitochondria; somatic hybrid; recombination
Online: 29 July 2019 (05:21:51 CEST)
Plant male sterility refers to the failure in the production of fertile pollen. It occurs spontaneously in natural populations and may be caused by genes encoded in the nuclear (genic male sterility; GMS) or mitochondrial (cytoplasmic male sterility; CMS) genomes. This feature has great agronomic value for the production of hybrid seeds and has been widely used in crops, such as corn, rice, wheat, citrus, and several species of the family Solanaceae. Mitochondrial genes determining CMS have been uncovered in a wide range of plant species. The modes of action of CMS have been classified in terms of the effect they produce in the cell, which ultimately leads to a failure in the production of pollen. Male fertility can be restored by nuclear-encoded genes, termed restorer-of-fertility (Rf) factors. CMS from wild plants has been transferred to species of agronomic interest through somatic hybridization. Somatic hybrids have also been produced to generate CMS de novo upon recombination of the mitochondrial genomes of two parental plants or by separating the CMS cytoplasm from the nuclear Rf alleles
ARTICLE | doi:10.20944/preprints201910.0187.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Salt caverns; salt structures; technical storage potential; hydrogen storage
Online: 16 October 2019 (11:40:43 CEST)
The role of hydrogen in a future energy system with a high share of variable renewable energy sources (VRES) is regarded as crucial in order to balance fluctuations in electricity generation. These fluctuations can be compensated for by flexibility measures such as the expansion of transmission, flexible generation, larger back-up capacity and storage. Salt cavern storage is the most promising technology due to its large storage capacity, followed by pumped hydro storage. For the underground storage of chemical energy carriers such as hydrogen, salt caverns offer the most promising option owing to their low investment cost, high sealing potential and low cushion gas requirement. This paper provides a suitability assessment of European subsurface salt structures in terms of size, land eligibility and storage capacity. Two distinct cavern volumes of 500,000 m3 and 750,000 m3 are considered, with preference being given for salt caverns over bedded salt deposits and salt domes. The storage capacities of individual caverns are estimated on the basis of thermodynamic considerations based on site-specific data. The results are analyzed using three different scenarios: onshore and offshore salt caverns, only onshore salt caverns and only onshore caverns within 50 km of the shore. The overall technical storage potential across Europe is estimated at 84.8 PWhH2, 27% of which constitutes only onshore locations. Furthermore, this capacity decreases to 7.3 PWhH2 with a limitation of 50 km distance from shore. In all cases, Germany has the highest technical storage potential, with a value of 9.4 PWhH2, located onshore only in salt domes in the north of the country. Moreover, Norway has 7.5 PWhH2 of storage potential for offshore caverns, which are all located in the subsurface of the North Sea Basin.
ARTICLE | doi:10.20944/preprints201802.0151.v1
Subject: Biology, Plant Sciences Keywords: color tests; thin layer chromatography; chemotaxonomy; secondary metabolites; solvent system
Online: 24 February 2018 (08:28:11 CET)
Presence and identity of secondary metabolites are two of the main components of lichen taxonomy. Aromatic compounds formed via the acetyl-polymalonate pathway are the most studied lichen substances. In addition, compounds derived from the mevalonic acid pathway (e.g., terpenes and steroids) are sometimes detected in the medulla. However, their identity and value as diagnostic characters in the genus Usnea are yet poorly understood despite the fact that they were mentioned in several taxonomical papers. We conclude that i) aside from the previously recognized polyphenolic compounds, carbohydrates and steroids are also detected in the medulla of some Usnea species; ii) the use of sulfuric anisaldehyde reagent greatly improves the detection of terpenes, carbohydrates and steroids compared with the sulfuric acid reagent routinely used in thin layer chromatography; iii) among carbohydrates, we detected arabitol and sucrose in the medulla; iv) steroids and terpenes remain unidentified and deserve further investigations.
ARTICLE | doi:10.20944/preprints201611.0022.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: mixing time; LIF; CFD; SPH; stirred tank
Online: 3 November 2016 (09:22:18 CET)
Performing optimisation and scale-up studies of crystallisation systems requires accurate and computationally efficient mathematical models. The assumption of the ideal mixing conditions in batch reactors typically produce inaccurate results while the computational expense of CFD models is still prohibitively high. Therefore, in this work, a new intermediary approach is proposed that takes into account the non-ideal mixing conditions in the reactor and requires less computational resources than full CFD simulations. Starting with the Danckwerts concept of the intensity of segregation, an analogy between its application to chemical reactions and the kinetics of the crystallisation phenomena (such as nucleation and growth) has been made. As a result, the modified kinetics expressions have been derived which incorporate the effect of non-idealities present in stirred reactors. This way, based on the experimental measurements of the mixing time using the Laser Induced Fluorescence (LIF) technique, computationally more efficient mathematical models can be developed in two ways: (1) the accurate semi-empirical correlations are available for standard mixing configurations with the most often used types of impellers, (2) CFD simulations can be utilised for estimation of the mixing time; in this case it is necessary to simulate only the mixing process. The benefits offered by the LIF experimental technique have been demonstrated and some frequent problems in its application analysed. The mixing time results for configurations with and without baffles for three types of impellers and four different rotational speeds have been presented. The false shorter mixing times in the non-baffled configurations have been observed and this phenomena explained by the existence of two segregated zones in the reactor and confirmed by additional experiments. The precise measurements in these cases have been shown as difficult using the LIF technique, particularly for higher rpms. The experimental data has been compared to the preliminary simulation results obtained from the Smoothed Particle Hydrodynamics method and the standard k-ε turbulence model with the modest success. The shortcomings of the SPH model have been recognized and the directions for the future work discussed.
TECHNICAL NOTE | doi:10.20944/preprints201811.0259.v1
Subject: Engineering, Civil Engineering Keywords: risk management; deterministic; probabilistic; engineering cost estimating; uncertainty; cost estimating methods; urban drainage infrastructure; Capital Improvement (CIP) Programs
Online: 12 November 2018 (04:27:22 CET)
Accurate and reliable project cost estimates are fundamental to achieve successful municipal capital improvement (CIP) programs. Engineering cost estimates typically represent critical information for key decision makers to authorize and efficiently allocate the necessary funds for construction, budgeting, to generate a request for proposals, contract negotiations, scheduling, etc. for these reasons, cost estimators are using different estimating methods and approaches that allow for required levels of accuracy. As the project’s scope becomes more detailed and the potential risks are identified and/or the project design stage progresses these cost estimates are revised and updated. In this paper, the most common project cost estimation methods and approaches were collected and categorized into two main groups of (1) probabilistic and (2) deterministic methods. Under these groups overall ten different methods were identified and discussed addressing their requirements, advantages, and shortcomings, including the potential risk that can positively or negatively affect the project’s cost outcome. This paper will be a good resource for professionals who are in budget development and/or are seeking to a better understanding of different methods in determining an appropriate base cost margin and produce a meaningful and reliable project cost estimate.
ARTICLE | doi:10.20944/preprints201711.0151.v1
Subject: Social Sciences, Other Keywords: psychopharmacology; mental health; addiction; biopsychology
Online: 23 November 2017 (08:51:06 CET)
This study investigated the psychosocial factors influencing substance abuse among undergraduates. The study was conducted in Ekiti State university Ado Ekiti. 150 participants who are undergraduates of the university were used in this research. They consist of 82 males and 68 females selected from all faculties in the institution. 3 questionnaires were administered to respondent to measure the factors influencing substance abuse and the level at which they are abused. Independent T-test, multiple regression and Pearson Correlation method were used to analyze the data collected. Five hypotheses were tested: hypothesis 1, 2, 3 and 4 were significant while hypothesis 5 was insignificant. It was observed that there was significant influence of religiosity on substance abuse among undergraduates, the result also revealed that there was a significant influence of self-esteem on substance abuse among undergraduates, it also revealed that religiosity and self-esteem jointly predicted substance abuse among undergraduates, likewise the result also show that there was significant influence of sex on substance abuse among undergraduates and finally the result revealed there was no significant relationship between religiosity and self-esteem among undergraduates. The results were discussed in line with relevant empirical literatures, while conclusion and recommendations subsequently followed.
ARTICLE | doi:10.20944/preprints201805.0309.v1
Subject: Engineering, Construction Keywords: Acoustic design; Reverberation time; Clarity; Lateral fraction; Acoustic measurements; Classical concert hall
Online: 22 May 2018 (13:49:31 CEST)
This study aims at an acoustic design of the classical concert hall and evaluation of the acoustic performance. In terms of three acoustic parameters (i.e., reverberation time (RT), clarity (C80), and lateral fraction (LF)), this study performed acoustic simulation modeling and site measurement with the K Art Hall located in South Korea as a case study. First, in order to meet the acoustic performance of the K Art Hall (target RT: 1.4~1.7 seconds, target C80: -2dB or more +2dB or less, and target LF: 10~35%), the finish materials and shape of the room as an interior acoustic design were determined. Second, the average values of the RT, C80, and LF using the acoustic simulation modeling were estimated at 1.4 second, 1.2~1.6 dB, and 29%, respectively. Third, the average values of the RT, C80, and LF through site measuring were measured at 1.5~1.64 second, 0.07~1.31dB, and 22.22~31.37%, respectively. Thus, the results of both the acoustic simulation modeling and site measuring were analyzed so as to satisfy the target acoustic performance. The results of this study will help the decision-makers (i.e., owner, construction managers, etc.) to plan the classical concert hall in terms of the RT, C80, and LF.
REVIEW | doi:10.20944/preprints201711.0081.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Marfan; connective tissue disease; irritable bowel syndrome; hernia
Online: 14 November 2017 (04:08:45 CET)
Symptoms attributed to the gastrointestinal manifestations of multi-system disorders play an important role in the long-term management of these conditions. Gastrointestinal complications of a variety of connective tissue disorders have been studied and there is an increased interest in the incidence and prevalence of these symptoms. Descriptions of the occurrence of gastrointestinal complications in Marfan syndrome have appeared infrequently in the medical literature. In this review article we focus on both structural and functional gastrointestinal pathology that may occur in patients with Marfan syndrome.
ARTICLE | doi:10.20944/preprints201607.0082.v1
Subject: Arts & Humanities, General Humanities Keywords: Africa, African women, Christianity, Igbo society, patriarchy, post-colonialism, feminism, womanism
Online: 27 July 2016 (04:18:57 CEST)
The African society is one of the societies with rich culture and traditions. Apart from the indigenous religion of Africa, Christianity and Islam are worshiped as the major religions of the African society. Literature reflects a great amount of influence of religions on the existing societies, people and cultures. African literature often mirrors the clash of indigenous religion with Christianity. In the writings of African authors one can find the elements of Christian beliefs and practices. The present paper, however, is focused on the African woman novelist Buchi Emecheta’s selected four novels: Second-Class Citizen (1974), The Bride Price (1976), The Slave-Girl (1977) and The Joys of Motherhood (1979). The paper attempts to discuss the impact of Christianity on the social and cultural aspects of the African society with special focus on African women. The findings reveal the positive as well as negative impacts of the new religion on African people and on the position of African women through the characters present in the selected novels. With the medium of writing and through Christianity, Emecheta seek to educate her society and improve upon the position of the African women.
ARTICLE | doi:10.20944/preprints201804.0271.v1
Online: 20 April 2018 (14:51:02 CEST)
A review of the concept of "fitness" as it is used in evolutionary theory.
REVIEW | doi:10.20944/preprints201810.0763.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Microbial fuel cell (MFC); fuel cell elements; design; energy generation; Scaling up; configuration
Online: 2 November 2018 (10:04:38 CET)
Fossil fuels and carbon origin resources are affecting our environment. Therefore, alternative energy sources have to be established to co-produce energy along with fossil fuels and carbon origin resources until it is the right time to replace them. Microbial Fuel Cell (MFC) is a promising technology in the field of energy production. Compared to the conventional power sources it is more efficient and not controlled by the Carnot cycle. Its high efficiencies, low noise, and less pollutant output could make it revolutionize in the power generation industry with a shift from centrally located generating stations and long-distance transmission lines to dispersed power generation at load sites. In this review, several characteristics of the MFC technology will be highlighted. First, a brief history of abiotic to biological fuel cells and subsequently, microbial fuel cells is presented. Second, the focus is then shifted to elements responsible for the making MFC working with efficiency. Setup of the MFC system for every element and their assembly is then introduced, followed by an explanation of the working machinery principle. Finally, microbial fuel cell designs and types of main configurations used are presented along with scalability of the technology for the proper application.
ARTICLE | doi:10.20944/preprints201811.0096.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: machine learning; stacking; forecasting; regression; sales; time series
Online: 5 November 2018 (09:54:54 CET)
In this paper, we study the usage of machine learning models for sales time series forecasting. The effect of machine learning generalization has been considered. A stacking approach for building regression ensemble of single models has been studied. The results show that using stacking technics, we can improve the performance of predictive models for sales time series forecasting.
ARTICLE | doi:10.20944/preprints201812.0322.v1
Subject: Engineering, Other Keywords: Futuristic Architecture; Neo-futurism; Deconstructivism; Modernism; Antonio Sant’ Elia
Online: 27 December 2018 (11:31:13 CET)
The Italian Architect Antonio Sant’Elia is considered the father of Futurist Architecture, the one who envisioned the future of cities on the basis of the native population’s work culture and habitual traits. It has been a century since his ideas were introduced in his ‘L-Architettura Futurista - Manifesto’ and later circulated by F.T. Marinetti, today they are making a prodigious impact on the architecture style of the entire world. His revolutionary ideas percolated through the murky aftermath of 19th & 20th century art movements. His out-worldly pre-modernist principles gave rise to the notion of exclusive habitats for generations and started the post-war trend of housing typologies as an industrialized and fast track medium of creating ample habitats. This review paper outlines the ideas and design theory of Antonio Sant’Elia through the advancements and achievements of the 20th & 21st century architects and their significant difference with the rest of historical architecture along with identification of elements of futurist principles in different architectural movements. The paper also makes a deliberate attempt to establish a timeline of developments within the said premise for futurist architecture.