1,375 research outputs found

    A New Phenomenology for the Disordered Mixed Phase

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    A universal phase diagram for type-II superconductors with weak point pinning disorder is proposed. In this phase diagram, two thermodynamic phase transitions generically separate a ``Bragg glass'' from the disordered liquid. Translational correlations in the intervening ``multi-domain glass'' phase are argued to exhibit a significant degree of short-range order. This phase diagram differs significantly from the currently accepted one but provides a more accurate description of experimental data on high and low-Tc_c materials, simulations and current theoretical understanding.Comment: 15 pages including 2 postscript figures, minor changes in published versio

    Vulnerability of the mosquito larvae to the guppies (Poecilia reticulata) in the presence of alternative preys

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    Background & objectives: The predatory potential of the larvivorous fishes can be affected by the presence of alternative preys. In the present study the predation pattern of the sewage dwelling Poecilia reticulata (Peters 1872) on the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae) was evaluated in the presence of alternative preys. Methods: The predation of Cx. quinquefasciatus larvae by different size groups of P. reticulata fishes was evaluated. In addition to this, the niche breadth (N) and diet breadth (B) were measured following Manly’s selectivity index (Si) as an indicator of variation of such predation pattern in the presence of alternative prey types, like chironomid larvae and tubificid worms.Results: The consumption of IV instar Cx. quinquefasciatus larvae by individual P. reticulata ranged between 65 and 84 in a 3 h feeding period and varied with the size of fish (F2, 33 = 34.91; p<0.001). The selectivity coefficient revealed a significantly low preference for the Cx. quinquefasciatus larvae (0.16, CL: 0.05 – 0.27; p< 0.05) compared to the chironomid larvae and tubificid worms, when all the three prey types were present. The niche breadth (N) and diet breadth (B) ranged from 0.77 to 0.92 and 0.69 to 0.93, respectively. The total consumption of all the prey types varied with the predator density, but the selectivity index for the mosquito larvae was significantly low in all the instances.Interpretation & conclusion: P. reticulata can consume a good number of mosquito larvae, with the consumption rate varying with the body size. P. reticulata fishes exhibit low preference for mosquito larvae as prey in the presence of alternative controphic preys like chironomid larvae and tubificid worms. Though establishment and sustenance of P. reticulata in new habitats will be favoured by the presence of alternative preys, but vulnerability of mosquito larvae may be reduced with availability of multiple preys in natural conditions

    Correspondence of butterfly and host plant diversity: Foundation for habitat restoration and conservation

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    At a spatial scale, the diversity of butterflies varies with numerous factors including the availability of the host plant species. In parity with this proposition, the correspondence of diversity of butterfly and plant in the background&nbsp;of the urban–rural gradient was evaluated using Kolkata, India, as a model study area. The results reveal significant positive correlation between the diversity of butterflies and the plants, with the different values for&nbsp;the suburban, rural, and urban areas. Identification of the butterfly loads for the plants in the respective areas can be useful in enhancing the conservation of the butterflies through enhanced plantation of the concerned plant species. Alternatively, the disclosure of the generalist and specialist pattern of the plant species preference by the butterflies may be useful in enhancing the population of the respective species in the concerned&nbsp;areas. The conservation strategy for butterfly species may be refined through the use of both or any one of the&nbsp;quantitative assessment of the butterfly–plant links in the urban–rural gradient in Kolkata, India, and similar&nbsp;places in the world

    SO(10) unification with horizontal symmetry

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    We extend the nonsupersymmetric SO(10) grand unification theories by adding a horizontal symmetry, which connects the three generations of fermions. Without committing to any specific symmetry group, we investigate the 1-loop renormalization group evolutions of the gauge couplings with one and two intermediate breaking scales. We find that depending on the SO(10) breaking chains, gauge coupling unification is compatible with only a handful of choices of representations of the Higgs bosons under the horizontal symmetry.Comment: 21 pages, 6 tables. v2: Further clarifications added primarily in Discussions Section, References updated, to be published in PR
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