3,096 research outputs found

    Tropical rainforest bird community structure in relation to altitude, tree species composition, and null models in the Western Ghats, India

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    Studies of species distributions on elevational gradients are essential to understand principles of community organisation as well as to conserve species in montane regions. This study examined the patterns of species richness, abundance, composition, range sizes, and distribution of rainforest birds at 14 sites along an elevational gradient (500-1400 m) in the Kalakad-Mundanthurai Tiger Reserve (KMTR) of the Western Ghats, India. In contrast to theoretical expectation, resident bird species richness did not change significantly with elevation although the species composition changed substantially (<10% similarity) between the lowest and highest elevation sites. Constancy in species richness was possibly due to relative constancy in productivity and lack of elevational trends in vegetation structure. Elevational range size of birds, expected to increase with elevation according to Rapoport's rule, was found to show a contrasting inverse U-shaped pattern because species with narrow elevational distributions, including endemics, occurred at both ends of the gradient (below 800 m and above 1,200 m). Bird species composition also did not vary randomly along the gradient as assessed using a hierarchy of null models of community assembly, from completely unconstrained models to ones with species richness and range-size distribution restrictions. Instead, bird community composition was significantly correlated with elevation and tree species composition of sites, indicating the influence of deterministic factors on bird community structure. Conservation of low- and high-elevation areas and maintenance of tree species composition against habitat alteration are important for bird conservation in the southern Western Ghats rainforests.Comment: 36 pages, 5 figures, two tables (including one in the appendix) Submitted to the Journal of the Bombay Natural History Society (JBNHS

    WTO agreements and quality concerns in Indian Fisheries

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    WTO agreements are legal ground rules of international commerce. As several facets of WTO agreements are discussed in this short course this paper will be a snapshot of Sanitary and Phytosanitary Agreement popularly known as SPSA which is a non-tariff barrier in international trade. The Agreement on the Application of Sanitary and Phytosanitary measures sets out the basic rules for food safety and animal and plant health standards. Safe and hygienic food is preferred anywhere in the world. More so in the northern world where advances in science have increased the level of awareness regarding the health ailments caused due to consumption of unsafe food. This has lead to development of food safety standards in these countries. Not only do these countries adopt these standards but also expect other countries to follow them giving rise to a plethora of issues. The general nature of such food standards can be said to be (1) a growing use of risk analysis (2) treatment of public health as a primary goal of food safety regulations (3) emphasis on a farm-to-fork approach in addressing food safety hazards (3) adoption of HACCP for microbial quality control (4) emergence of newer and extensive regulations to handle newly identified hazards

    Simultaneous determination of four active pharmaceuticals in tablet dosage form by reversed-phase high performance liquid chromatography

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    Purpose: To develop a single, low-cost and rapid analytical method for the simultaneous determination of four active components - chlorpheniramine maleate, paracetamol, phenylephrine hydrochloride and caffeine – in a tablet dosage form. Method: This method was based on reverse-phase high performance liquid chromatography (RPHPLC) and involved the use of a C-18 column (250 × 4.6 mm, 5.0 μm), a mobile phase consisting of buffer solution and methanol at a flow rate of 1.00 mL/min, and gradient determination with UV detection at 220 nm. Results: Retention time was 4.33, 10.36, 13.85, and 17.35 min for phenylephrine hydrochloride, paracetamol, caffeine, and chlorpheniramine maleate, respectively. Specificity data showed no interference from the excipients, and accuracy of the method was close to 100 %. The method was validated as per the guidelines of International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), and all the results met the acceptance criteria for accuracy, precision, linearity, specificity, limit of quantitation, limit of detection, and robustness. Conclusion: This method can successfully perform quantitative assessment of phenylephrine HCl, chlorpheniramine maleate, paracetamol, and caffeine in tablet combination dosage forms faster and more cost-effectively than conventional methods

    Bioencapsulation strategy and highly unsaturated fatty acids (HUFA) enrichment in Artemia franciscana nauplii by using marine trash fish Odonus niger liver oil

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    To investigate the maximum accumulation of highly unsaturated fatty acids (HUFA) in Artemia franciscana nauplii through bioencapsulation process, five different concentrations (0 - 4%) of emulsified Odonus niger liver oil were prepared. The prepared emulsions were used to enrich A. franciscana at different time intervals of 6, 12, 18 and 24 h. After the enrichment period, the fatty acid composition of the nauplii were analysed and estimated individually along with freshly hatched A.franciscana and O. niger liver oil. The HUFA content such as linoleic (18: 2n-6), linolenic (18: 3n-3), arachidonic (20: 4n-3 + n-6), eicosapentaenoic (20: 5-n3) and docosahexaenoic (22: 6n-3) acids were 12.87, 0.21, 2.66, 2.86 and 2.30% dry weight (DW), respectively, in O. niger liver oil, and 8.60, 17.20, 1.80, 2.40 and 0.1% DW, respectively, in freshly hatched A. franciscana. During 6 – 24 h of enrichment period, all the above HUFA increased considerably from 8.76 to 10.84, 17.24 to 23.84, 1.16 to 3.98, 2.45 to 5.88 and 0.30 to 2.69% DW, respectively. The increase in the level of individual HUFA of A. franciscana enriched with various concentrations of emulsified liver oil at different time durations showed a positive linear relationship and the correlation coefficient obtained were statistically significant (P< 0.05)

    Spin Polarizations at and about the Lowest Filled Landau Level

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    The spin polarization versus temperature at or near a fully filled lowest Landau level is explored for finite-size systems in a periodic rectangular geometry. Our results at ν=1\nu=1 which also include the finite-thickness correction are in good agreement with the experimental results. We also find that the interacting electron system results are in complete agreement with the results of the sigma model, i.e., skyrmions on a torus have a topological charge of Q2Q \ge 2 and the Q=1 solution is like a single spin-flip excitation. Our results therefore provide direct evidence for the skyrmionic nature of the excitations at this filling factor.Comment: 4 pages, REVTEX, and 4 .ps files, To be published in Europhysics Letter

    Structure of 9α,19-dihydroxy-4-androstene-3,17-dione

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    C19H26O4, M1 = 318.41, orthorhombic, P212121, a = 10.591 (1), b = 11.133 (1), c = 13.657 (2) Å, V – 1610.29 Å3, Z = 4, Dm (flotation in KI) = 1.301, Dx = 1.313 g cm-3, Mo Kα, Å = 0.7107 Å, μ = 0.85 cm-1, F(000) = 688, T = 293 K, R – 0.057 for 1253 significant reflections. The Å ring is disordered with atoms C(2) and O(19) occupying two possible sites. The molecules are held together by a hydrogen bond [O(9)…O(17) = 2.89 Å]

    Conductance of a Mott Quantum Wire

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    We consider transport through a one-dimensional conductor subject to an external periodic potential and connected to non-interacting leads (a "Mott quantum wire"). For the case of a strong periodic potential, the conductance is shown to jump from zero, for the chemical potential lying within the Mott-Hubbard gap, to the non-interacting value of 2e^2/h, as soon as the chemical potential crosses the gap edge. This behavior is strikingly different from that of an optical conductivity, which varies continuously with the carrier concentration. For the case of a weak potential, the perturbative correction to the conductance due to Umklapp scattering is absent away from half-filling.Comment: 4 pages, RevTex, 1 ps figure included; published versio

    Quantum thermodynamics at critical points during melting and solidification processes

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    We systematically explore and show the existence of finite-temperature continuous quantum phase transition (CTQPT) at a critical point, namely, during solidification or melting such that the first-order thermal phase transition is a special case within CTQPT. Infact, CTQPT is related to chemical reaction where quantum fluctuation (due to wavefunction transformation) is caused by thermal energy and it can occur maximally for temperatures much higher than zero Kelvin. To extract the quantity related to CTQPT, we use the ionization energy theory and the energy-level spacing renormalization group method to derive the energy-level spacing entropy, renormalized Bose-Einstein distribution and the time-dependent specific heat capacity. This work unambiguously shows that the quantum phase transition applies for any finite temperatures.Comment: To be published in Indian Journal of Physics (Kolkata

    Utilization of steel slag in development of sustainable and durable concrete.

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    This paper reflects the results of an experimental investigation of the strength, permeability, abrasion, carbonation, and shrinkage characteristics of concrete containing various percentages of steel slag as partial replacement of natural fine aggregates. M 30 Grade concrete was designed as per specific national specifications. Steel slag was used to replace natural sand in the range of 0– 50%. It was observed that the steel slag blended concrete with up to 50% substitution exhibited a comparable compressive and flexural strength when compared to the control specimens. From the Dorry’s abrasion test, it was noted that the specimens could be implemented in heavy-duty floor tiles and even extended to pavement construction. The shrinkage strains, water permeability, and carbonation of steel slag blended concrete were observed to be increasing with increasing replacement amounts of steel slag in the place of natural fine aggregates. The concrete containing steel slag replacing up to 40% of natural fine aggregates can be recommended for all heavy load involving structural applications, and substitution levels beyond 40% could be recommended for non-structural applications, pavements, etc
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