148 research outputs found

    Coral reef fish abundance and diversity of seagrass beds in Kavaratti atoll, Lakshadweep, India

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    The community organization of coral reef fishes in the seagrass sub-habitat of Kavaratti toll, Lakshadweep, India was studied during the period from January 1991 to June 1992. Twenty-seven families represented by 65 species were recorded by the visual censes method. The community diversity for families and species was 2.49 and 3.14 respectively. Juveniles and sub-adults of the most adult reef fish, which inhabit other sub-habitats, were recorded here. The high species diversity in the seagrass beds is due to their roles as nurseries, shelter and foraging grounds for many species. Labridae, Chaetodontidae, Acanthuridae and Mullidae were the most speciose families. Ocurrence of siganids was highly seasonal. The cover that seagrass canopy provides conceals many species and perhaps influenced counts. The occurrence of balistids could be related to the presence of interstitial and patches and abundant invertebrate food. Scorpaenids subsisted on abundant invertebrates and juveniles fishes. High counts and pronounced variations make seagrass beds unstable habitats. However, monsoon assemblages were relatively stable perhaps due to lack of excessive new recruits and a habitat shift by most species

    Community organization of coral reef fishes in the rubble sub-habitat of Kavaratti Atoll, Lakshadweep, India

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    A visual census of the coral reef fishes, conducted during January 1991 to June 1992, indicated the occurrence of 64 species belonging to fifteen families in the rubble sub-habitat of Kavaratti A toll (Lat. 10°33'N; Long. 7Z038'E) in Lakshadweep. The community diversity for families and species was 2.68 and 3.58 respectively. Family assemblages were not stable during different seasons. Labridae and pomacentridae made use of the rubble zone efficiently. Pomacentrids were characteristically site attached but varied in relative abundance. Rhinecanthus aculeatus among balistids depended on rubble for food and nesting sites. The occurrence of chaetodontids was due to their flexible feeding habits, in the absence of coral cover. Availability of food strongly determined the distribution of the surgeonfish, Acanthurus triostegus. The abundant turf algae harbored by rubble attracted schools of sub-adult herbivores resulting in variations

    Habitat distribution and species diversity of coral reef fishes in the reefslope of the Kavaratti atoll, Lakshadweep, India

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    Habitat distribution and species diversity of coral reef fishes in the reef slope of Kavaratti atoll was studied by the visual census method during January 1991 to June 1992. Twenty seven families represented by 121 species, the highest for any sub-habitat of the atoll were recorded. The community diversity, also the highest both for families and species was 3.32 and 4.45 respectively. Family assemblages were not stable between censuses and pre-monsoon, mon- soon and post-monsoon seasons. Labridae, Chaetodontidae, Balistidae, Pomacentridae and Acanthuridae were the most specious families. Low abundance of coral feeders indicated unhealthy reef condition. While dominance of some surgeonfish indicated availability of al- gal food, balistids provided clues for topographic complexity

    Community organization of reef fishes in the live coral sub-habitat of Kavaratti atoll, Lakshadweep, India

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    Data on the community organization of coral reef fishes of Kavaratti atoll, Lakshadweep, India were collected during the period January 1991 to June 1992. Species were enumerated by visual census on the live coral sub-habitat for frequency of occurrence, abundance, composition, diversity, evenness and seasonal variation in community parameters. As the live coral zone was composed of a single species of ramose coral (Acropora formosa), only 14 families and 39 species of reef fishes made use of this zone, the community diversity being 1.84 and 3.16. Chaetodontids, labrids and pomacentrids were comparatively more abundant. Varying habitats of chaetodontids explain their restricted distribution. Live coral does not seem to be a preferred habitat of labrids. The occurrence of epinephelids was influenced by readily available prey. Most species among live coral were resident, variations resulted from factors affecting new recruits rather than habitat shifts

    Occurrence of juvenile fishes on the seagrass beds of Kavaratti Atoll, Lakshadweep, India

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    In the atolls of Lakshadweep, juveniles of Acanthuridae and Labridae were most abundant on seagrass beds, the former during pre-monsoon and postmonsoon periods and the latter in pre-monsoon. Schooling species showed variable recruitment. Non-schooling species were rare. Peak settlement was observed during pre-monsoon and post-monsoon seasons. Continuous occurrence of juveniles in different size ranges confirms the continuous spawning habits. Chaetodontids and holocentrids occurred consistently round the year. Seasonality in occurrence was most pronounced in Carangidae and Siganidae, but not so in Apogonidae, Lutjanidae and Mullidae. Seasonal abundance of juveniles was influenced by summer peaks, timing and magnitude of settlement, adult spawning and local migrations. Abundance of larvae increased with salinity. Juvenile abundance, independent of environmental parameters seemed to be controlled by seasons, tides and currents. Lunar phases and abundance of juveniles were found to be co-related

    Reproductive biology of some common coral reef fishes of the Indian EEZ

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    The reproductive biology of some common coral reef fishes from the Lakshadweep ( 8" to 12"N and 71" 45' to 73"45'E) and the Gulf of Mannar (8"48' to 9"14'N and 799' to 79O14'E) in the Indian EEZ during January 1991 to June 1992 is reported. Protogyny was prominent in labrids, while other species either matured synchronously or differentially, with males maturing earlier or later than females. Sex-ratio indicated that females were dominant in most species. Fecundity estimates varied greatly, from 700 to 2,25,850 ova per female. Whenever the environment is favourable the coral reef fish spawn on a daily, weekly, fortnightly and monthly basis. Total fecundity per year, therefore, is presumably very high. Most species appeared to be perennial spawners, some showed small breaks, while very few indicated biannual spawning. Continuous occurrence of juveniles in different size ranges confirmed the continuous spawning habits. Spawning activity was minimum during monsoon seasons, evidently an adaptation to tide over adverse environmental conditions prevailing at that time lest the eggs and larvae are transported far and wide. This was corroborated by peak settlement during pre-monsoon and post-monsoon seasons

    SUPPORTIVE THERAPY: AN OPTION TO ENHANCE HOST IMMUNITY AGAINST COVID-19

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    The threat posed by COVID 19 outbreak, which is considered to be a global pandemic, is immeasurably affecting all the communities worldwide. COVID-19 is a zoonotic disease, which can affect birds, humans and, other animals. The emergence of this pandemic has been creating a tragic situation worldwide by affecting more people through human-human transmission. The burden (both healthwise and economic) placed by the disease is so huge that any measures to improve the current situation, to fasten up the recovery of already affected patients and, to reduce the risk of death and health deterioration should be considered. Vaccination, being the hope in the scenario, helps in preventing the condition to an extent, but in the absence of availability of a proper drug regimen to fight off COVID 19, the requirement of the need to find a system to control the severity of the infection is a necessity Nutritional supplementation helps in boosting up the immune system especially, vitamins like vitamin C, Vitamin D, Zinc, Omega 3 fatty acids, etc. They also exhibit established immunomodulatory, antiviral as well as anti-inflammatory effects. Pieces of evidence have also highlighted the importance of supportive therapy using nutrient supplements in covid patients as it helps in prominent decreasing of SARS CoV2 load of the virus and also significantly reduces the hospitalization period. Hence the nutritional levels of each of the infected person must be assessed before initiating the anti-viral therapy. The search criteria used were PubMed, Medscape, google scholar, etc. The keywords used to search were COVID 19 Supportive therapy, Vitamin D, Vitamin C, Nutrient supplementation, Host immunity, etc. The range of years is between 1978 and 2021

    Analysis of the limitations in the oxygen reduction activity of transition metal oxide surfaces

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    The oxygen reduction reaction (ORR) is the key bottleneck in the performance of fuel cells. So far, the most active and stable electrocatalysts for the reaction are based on Pt group metals. Transition metal oxides (TMOs) constitute an alternative class of materials for achieving operational stability under oxidizing conditions. Unfortunately, TMOs are generally found to be less active than Pt. Here, we identify two reasons why it is difficult to find TMOs with a high ORR activity. The first is that TMO surfaces consistently bind oxygen atoms more weakly than transition metals do. This makes the breaking of the O–O bond rate-determining for the broad range of TMO surfaces investigated here. The second is that electric field effects are stronger at TMO surfaces, which further makes O–O bond breaking difficult. To validate the predictions and ascertain their generalizability for TMOs, we report experimental ORR catalyst screening for 7,798 unique TMO compositions that generally exhibit activity well below that of Pt

    An overview of vaccine development for COVID-19

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    The COVID-19 pandemic continues to endanger world health and the economy. The causative SARS-CoV-2 coronavirus has a unique replication system. The end point of the COVID-19 pandemic is either herd immunity or widespread availability of an effective vaccine. Multiple candidate vaccines - peptide, virus-like particle, viral vectors (replicating and nonreplicating), nucleic acids (DNA or RNA), live attenuated virus, recombinant designed proteins and inactivated virus - are presently under various stages of expansion, and a small number of vaccine candidates have progressed into clinical phases. At the time of writing, three major pharmaceutical companies, namely Pfizer and Moderna, have their vaccines under mass production and administered to the public. This review aims to investigate the most critical vaccines developed for COVID-19 to date

    Underpinning beneficial maize response to application of minimally processed homogenates of red and brown seaweeds

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    Sap from the fresh seaweed Kappaphycus alvarezii (KA) has been reported to improve crop growth, quality, and stress alleviation. However, limited studies are reported for the minimally processed aqueous homogenates (MPHs) derived from dry seaweeds. The present investigation was envisaged to characterize the MPHs from the red seaweed KA and a brown seaweed Sargassum wightii (SW) and also assess the effect of foliar application on maize (Zea mays) crop performance when applied alone or in proportions ranging from 0% to 100%. Two doses (0.35% and 0.7%) were compared with control. Both the MPHs contained several compounds like retronecine, tyrosyl-glycine, hexyl 2-furoate, 1-phosphatidyl-1D-myo-inositol, 12-(2,3-dihydroxycyclopentyl)-2-dodecanone, and trihomomethionine and many others that have known bioactivity for enhancing plant growth and providing stress tolerance. Both doses of MPHs enhanced crop growth and yield; however, the best response was in general observed at a lower dose. The MPH of SW at 100% gave the highest seed yield at a lower dose, which was also on par with that obtained under a lower dose of 100% KA. Other combinations, 80:20 and 40:60 KA : SW, were also found to give comparable yields. The highest dose of 100% MPH of SW was found on par with control, a phenomenon that was investigated in detail with respect to metabolites and antioxidant profile in leaves as well as membrane modeling. Higher ROS and certain sugar and organic acids were observed in 100% MPH of SW at a higher dose, although none of the antioxidant enzymes were significantly affected, nor was there any change in membrane characteristics of the leaf with respect to control as well as lower dose. Improvements in the seed yield were attributed to improved photosynthate production on account of higher dry matter accumulation in the MPH-treated plants, which may also be attributed to the presence of bioactive compounds in the biostimulants. In the future, it is imperative to direct scientific investigations towards the quantification and identification of the most effective concentrations of these compounds within MPHs to optimize plant responses. The study indicated the beneficial use of the MPHs towards increasing crop production by employing optimum dose as foliar spray to crops
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