703 research outputs found

    Diversity of reef fishes in trap fishery at Keelakarai, Gulf of Mannar, south-east coast of India

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    The diversity of finfishes caught in traps at Keelakarai, Gulf of Mannar was assessed quantitatively and qualitatively for a period of six years from July 2006 to June 2012. Average landing during the period was 109 t per year with maximum of 137 t during 2008-09. Among the 98 species of reef fishes landed, Siganus canaliculatus dominated (28%), followed by Scarus ghobban (21%). During the first two years of the study, S. ghobban dominated over S. canaliculatus and later the trend reversed. Family-wise, maximum contribution was by Siganidae (36%) followed by Scaridae (21%). Seasonally, the major peak was recorded during post-monsoon of 2009. The Shannon index of diversity was maximum during 2007-08. Cluster analysis indicated the highest similarity in species composition between 2010-11 and 2011-12. SIMPER analysis identified 26 species as most significant in creating the observed pattern of similarity for 90% cut off contributions. Ellipse plot showed statistically significant deviation in fish diversity between years. Reef fish landings showed an increasing trend from 2006-07 to 2008-09, a decline afterwards and then almost steady condition prevailed during the last two years of the study which implies that there is no scope for further increase in landings by trap fishery at Keelakarai

    Collinear order in a frustrated three-dimensional spin-12\frac12 antiferromagnet Li2_2CuW2_2O8_8

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    Magnetic frustration in three dimensions (3D) manifests itself in the spin-12\frac12 insulator Li2_2CuW2_2O8_8. Density-functional band-structure calculations reveal a peculiar spin lattice built of triangular planes with frustrated interplane couplings. The saturation field of 29 T contrasts with the susceptibility maximum at 8.5 K and a relatively low N\'eel temperature TN3.9T_N\simeq 3.9 K. Magnetic order below TNT_N is collinear with the propagation vector (0,12,0)(0,\frac12,0) and an ordered moment of 0.65(4) μB\mu_B according to neutron diffraction data. This reduced ordered moment together with the low maximum of the magnetic specific heat (Cmax/R0.35C^{\max}/R\simeq 0.35) pinpoint strong magnetic frustration in 3D. Collinear magnetic order suggests that quantum fluctuations play crucial role in this system, where a non-collinear spiral state would be stabilized classically.Comment: published version with supplemental material merged into the tex

    Marine macroalgae: Biodiversity from Indian waters

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    Marine ecosystems are the largest aquatic ecosystems on our planet, sustaining almost 50% of the overall world's biodiversity. Marine and terrestrial environments rely on various ecosystems, such as intertidal zones, tidal zones, the deep sea, coral reefs, salt marshes, estuaries, lagoons, and mangroves, which are crucial for their sustainability. Algae are autotrophic plants that live mostly in water and come in many different types, from Chlamydomonas, Chlorella and Diatoms, which are single-celled organisms, to Fucusand Sargassum, which are multicellular organisms. The classification of marine algae encompasses two primary categories: marine microalgae and marine macroalgae. Marine microalgae, often known as phytoplankton, are exclusively observable with the use of microscopes. Marine macroalgae, also known as seaweeds, seaplants, or aquatic plants, encompass all types of marine algae that are observable without the aid of microscopes (Ranjith et al., 2018)

    Incidence of kleptoparasitism on jelly fish Rhopilema hispidum from the Pamban coast of Palk Bay, Southeast coast of India

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    Incidence of kleptoparasitism on jelly fish Rhopilema hispidum from the Pamban coast of Palk Bay, Southeast coast of Indi

    Coral bleaching: causes, consequences and mitigation

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    The coral reefs are distributed in the tropical regions and cover less than one percent of the earth’s surface, but provide habitat for many species in the marine realm. The majority of reef building corals are found in tropical and subtropical waters and typically occur between 30° N and 30° S latitudes (Fig. 1). Coral reefs are greatly valued due for their beauty, biodiversity it encompasses and the products and services they provide to human society. The coral reefs are made of calcium carbonate secreted as skeletal material by the coral polyp. Coral polyps live in association with intracellular algae (zooxanthellae), which provide additional nutrition to the coral in its life processes. The association of coral polyp with zooxanthellae, restrict its distribution in waters up to the depth of 100 meters where sunlight would be available for the photosynthetic zooxanthellae. The worldwide of zooxanthellate corals in the different distribution eco-regions is a unique underwater ecosystem and provides annual net economic benefit around 30 billion dollars (Buddemeier et al., 2004 Pew Center on Global Climate Change, 44p). However, coral reefs are most vulnerable to Climate Change due to the stenothermic nature of coral polyps

    Biofilm-stimulated epithelium modulates the inflammatory responses in co-cultured immune cells

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    The gingival epithelium is a physical and immunological barrier to the microbiota of the oral cavity, which interact through soluble mediators with the immune cells that patrol the tissue at the gingival epithelium. We sought to develop a three-dimensional gingivae-biofilm interface model using a commercially available gingival epithelium to study the tissue inflammatory response to oral biofilms associated with “health”, “gingivitis” and “periodontitis”. These biofilms were developed by sequential addition of microorganisms to mimic the formation of supra- and sub-gingival plaque in vivo. Secondly, to mimic the interactions between gingival epithelium and immune cells in vivo, we integrated peripheral blood mononuclear cells and CD14+ monocytes into our three-dimensional model and were able to assess the inflammatory response in the immune cells cultured with and without gingival epithelium. We describe a differential inflammatory response in immune cells cultured with epithelial tissue, and more so following incubation with epithelium stimulated by “gingivitis-associated” biofilm. These results suggest that gingival epithelium-derived soluble mediators may control the inflammatory status of immune cells in vitro, and therefore targeting of the epithelial response may offer novel therapies. This multi-cellular interface model, both of microbial and host origin, offers a robust in vitro platform to investigate host-pathogens at the epithelial surface

    Agroforestry and grass buffer effects on water quality on grazed pasture watersheds

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    Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.Conservation practices including agroforestry and grass buffers are believed to reduce non point source pollution (NPSP) from grazed pasture watersheds. Agroforestry, a land management practice that intersperses agricultural crops with trees, recently received increased attention in the temperate zone due to its environmental and economic benefits. However, studies are limited that examined buffer effects on water quality on grazed pasture watersheds. Six small watersheds, two with agroforestry buffers, two with grass buffers, and two control watershdeds were used to test the hypothesis that agroforestry and grass buffers reduce NPSP from grazed pasture watersheds. Vegetation in grass buffer and pasture areas include red clover (Trifolium pretense L.) and lespedeza (Kummerowia stipulacea Maxim.) planted into fescue (Festuca arundinacea Schreb.). Eastern cottonwood trees (Populus deltoids Bortr. ex Marsh.) were planted into fescue in agroforestry buffers. Soils at the site are mostly Menfro silt loam (fine-silty, mixed, superactive, mesic Typic Hapludalfs). Watersheds were instrumented with two-foot H flumes, water samplers, and flow measuring devices in 2001. Composite water samples were analyzed for sediment, and total nitrogen after each runoff event to compare treatment differences. Watersheds with agroforerstry and grass buffers had significantly lower runoff volumes as compared to the control watersheds. The loss of sediment, and total nitrogen were smaller for the buffer watersheds. The results of the study suggest that establishment of groforestry and grass buffers help reduce NPSP pollution from grazed pasture watersheds. It is anticipated as trees grow and roots occupy more soil volume, the reduction in N in runoff should increase on the agroforestry watershed.Ranjith P. Udawatta (1, 2), Harold E. Garrett (2), and Robert L. Kallenbach (3) ; 1. Department of Soil, Environmental and Atmospheric Sciences. 2. Center for Agroforestry. 3. Department of Plant Sciences, University of Missouri, Columbia, MO 65211.Includes bibliographical references

    Animal hygiene and sustainable livestock production: impact of ground water contamination with arsenic

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    There is a growing concern all over the world about contamination of ground water with Arsenic. One of the major repercussions of arsenic contamination is degradation of animal hygiene that ultimately affects sustainable livestock production. The reports suggest that concentration of Arsenic in ground water of twenty one countries is well above the guideline values. Use of such contaminated water for animal husbandry and livestock production compromises with the hygienic value of animal products. Therefore, there is an urgent need to develop low cost treatment technologies for reducing the level of arsenic in ground water to maintain the hygiene and sustainability of livestock production. Most of the traditional treatment technologies are costly and less effective in reducing arsenic concentration to safer limits. Therefore, during present study, an attempt was made to design a low-cost algal adsorbent based filtration unit consisting of polyurethane columns with entrapped algal adsorbents. The column was made of adsorbents of algal origin like agar-agar, alginic acid, calcium alginate and Spirulina platensis biomass entrapped in polyurethane foam matrix. The performance of the column was assessed in terms of removal efficiency and the quantity of metal sequestered in unit time interval. The results from the study the show that algal biosorbents and S. platensis biomass combination has a capacity to adsorbed arsenic from aqueous solution. The simple design, easy fabrication and no energy requirement for the operation of the filtration unit developed under the present study is suitable to rural areas where arsenic contamination of ground water is adversely affecting the animal hygiene and sustained livestock production

    Growth performance of Spirulina (Arthrospira) platensis in a low cost medium: An assessment

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    The unialgal culture of Spirulina platensis was sub-cultured in Zarrouk’s medium under photoautotrophic conditions. Initially, indoor batch cultivation was carried out for a week in four different types of cultivation media viz., Zarrouk’s, Modified Zarrouk’s, prescribed Nallayam Research Centre (NRC), and Modified NRC. In modified medium, urea and phosphoric acid of NRC medium were replaced with sodium nitrate and dipotassium hydrogen phosphate (anhydrous) and concentration of ferrous sulphate heptahydrate was reduced. The batch and airlift indoor culture experiments were carried out with an illumination of 3500±100 lux, photoperiod of 12:12 hour light and dark periods and temperature of 24±1°C. The specific growth rate value was 5.7 % higher in Zarrouk’s medium as compared to modified NRC medium. However, the cost of modified NRC medium was considerably lower than Zarrouk’s medium; therefore, modified NRC medium was selected for outdoor studies. The outdoor mass cultivation was done under natural conditions with the solar radiation reaching the surface of culture was between 2160 and 8450 lux and temperature ranged from 27 to 34°C. An assessment of the performance of growth in batch, airlift and FRP (Fiber Reinforced Polymer) tanks revealed that culture grown in airlift units showed best growth which was evident from higher specific growth rate and number of doublings per day. There was a 3.4-fold increase in cell density (in terms of turbidity at 750 nm) of the cultures in such units. The growth in outdoor FRP tanks was also comparable to the airlift cultures

    A Prospective Surveillance Study of Candidaemia : Epidemiology, Risk Factors, Antifungal Treatment and Outcome in Hospitalized Patients

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    Funding This work was supported by the Wellcome Trust Strategic Award for Medical Mycology and Fungal Immunology 097377/Z/11/Z. Data collection was supported by a grant from Pfizer. GR was also supported by a research fellowship grant from Gilead Sciences. The collection of the isolates was funded by a Gilead Fellowship to GR. Acknowledgments We are grateful to microbiology colleagues throughout Scotland for submitting isolates. Antimicrobial sensitivity testing was performed by the Mycology Reference Laboratory, Public Health England, Bristol.Peer reviewedPublisher PD