ARTICLE | doi:10.20944/preprints201912.0359.v1
Subject: Earth Sciences, Geophysics Keywords: ocean waves; double-frequency microseisms; continental margin; continental slope
Online: 27 December 2019 (07:59:29 CET)
This study presents an exploration into identifying the interactions between ocean waves and the continental margin in the origination of double-frequency (DF, 0.1-0.5 Hz) microseisms recorded at 33 stations across East Coast of USA (ECUSA) during a ten-day period of ordinary ocean wave climate. Daily primary vibration directions are calculated in three frequency bands and projected as great circles passing through each station. In each band, the great circles from all stations exhibit largest spatial density primarily near the continental slope in the western North Atlantic Ocean. Generation mechanisms of three DF microseism events are explored by comparing temporal and spatial variations of the DF microseisms with the migration patterns of ocean wave fronts in Wavewatch III hindcasts. Correlation analyses are conducted by comparing the frequency compositions of and calculating the correlation coefficients between the DF microseisms and the ocean waves recorded at selected buoys. The observations and analyses lead to a hypothesis that the continental slope causes wave reflection, generating low frequency DF energy and that the continental shelf is where high frequency DF energy is mainly generated in ECUSA. The hypothesis is supported by the primary vibration directions being mainly perpendicular to the strike of the continental slope.
ARTICLE | doi:10.20944/preprints202011.0050.v1
Subject: Biology, Anatomy & Morphology Keywords: Nigella sativa; Curcuma longa; Pasteurella multocida; feed conversion ratio; gross pathological changes; histopathological changes
Online: 2 November 2020 (14:34:20 CET)
The antibiotic residues and pathogenic resistance against the drug are very common in poultry due to usage of antibiotics in their feed. It is the need of the time to use natural feed additives as effective alternatives instead of synthetic antibiotic. The aim of this study was to investigate the immune response of Nigella sativa and Curcuma longa in broilers under biological stress against Pasteurella multocida. The total 100, one-day old chicks were divided into 5 groups. The Groups 1 and 2 were served as control negative and control positive. Both control groups were receiving simple diet without any natural feed additives but infection was given in Group 2 at day 28 with the dose of 5.14×107 CFU by IV. Groups 3A & 3B were offered 2% seed powder of Nigella sativa, Groups 4A & 4B were offered Curcuma longa 1% in powdered form and Group 5A & 5B were offered both Curcuma longa 1% & Nigella sativa 2% in feed from day 1 and groups 3B, 4B and 5B were challenged with Pasteurella multocida. The Haemagglutination inhibition titter against Newcastle Disease Virus (NDV), feed conversion ratio, mortality, gross and histopathology were studied. The results of this study revealed that haemagglutination inhibition titers against NDV were highly significant (P< 0.05) in treated groups, highest titers (3A 6.8, 3B 6.4 and 5A 7.2) were obtained from treated Group. The feed conversion ratio (FCR) of Nigella sativa + Curcuma longa treated Groups (5A 1.57 and 3A 1.76) were higher as compared to other non-treated groups. The gross and histopathological changes were much severe in control positive, but less changes were seen in treated groups. Therefore, we recommend that natural feed additives; black cumin (Nigella sativa) and turmeric (Curcuma longa) act as immune enhancer in broilers against Pasteurella multocida.