645 research outputs found

    Haldane exclusion statistics and second virial coefficient

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    We show that Haldanes new definition of statistics, when generalised to infinite dimensional Hilbert spaces, is equal to the high temperature limit of the second virial coefficient. We thus show that this exclusion statistics parameter, g , of anyons is non-trivial and is completely determined by its exchange statistics parameter α\alpha. We also compute g for quasiparticles in the Luttinger model and show that it is equal to α\alpha.Comment: 11 pages, REVTEX 3.

    Shooting shadows: India’s struggle to reduce the burden of anaemia

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    Despite several efforts by the Government of India, the national burden of anaemia remains high and its growing prevalence (between 2015–2016 and 2019–2021) is concerning to India’s public health system. This article reviews existing food-based and clinical strategies to mitigate the anaemia burden and why they are premature and insufficient. In a context where multiple anaemia control programmes are in play, this article proposes a threefold strategy for consideration. First, except the Comprehensive National Nutrition Survey, 2016–2018, which measured Hb concentration among children and adolescents aged 1–19 years using venous blood samples, all national surveys use capillary blood samples to determine Hb levels, which could be erroneous. The Indian government should prioritise conducting a nationwide survey for estimating the burden of anaemia and its clinical determinants for all age groups using venous blood samples. Second, without deciding the appropriate dose of Fe needed for an individual, food fortification programmes that are often compounded with layering of other micronutrients could be harmful and further research on this issue is needed. Same is true for the pharmacological intervention of Fe tablet or syrup supplementation programmes, which is given to individuals without assessing its need. In addition, there is a dire need for robust research to understand both the long-term benefit and side effects of Fe supplementation programmes. Third and final, the WHO is in process of reviewing the Hb threshold for defining anaemia, therefore the introduction of new anaemia control programmes should be restrained

    Black Hole Entropy from a Highly Excited Elementary String

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    Suggested correspondence between a black hole and a highly excited elementary string is explored. Black hole entropy is calculated by computing the density of states for an open excited string. We identify the square root of oscillator number of the excited string with Rindler energy of black hole to obtain an entropy formula which, not only agrees at the leading order with the Bekenstein-Hawking entropy, but also reproduces the logarithmic correction obtained for black hole entropy in the quantum geometry framework. This provides an additional supporting evidence for correspondence between black holes and strings.Comment: revtex, 4 page

    Integration of biocontrol agents with fungicide, weedicide and plant growth regulator for management of stem and root rot of jute

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    Combination of chemical fungicides (viz., Carbendazim 50 WP and Tebuconazole 250 EC) and biocontrol agents (viz., Pseudomonas fluorescens Psfl1, P. striata Pst1, Azotobacter chrococcum Azbc3, Bradyrhizobium japonicum Brj4, Trichoderma aureoviridae S12, T. harzianum JTV2, T. virens JPG1, Aspergillus niger AN15 strains respectively either singly or in consortium) were used to counteract Macrophomina phaseolina, the causal organism of stem and root rot of jute. In addition, suitable plant growth regulator viz., Indole-3-acetic acid (100-1.0 µg/ppm) and herbicide Quizalofop ethyl 5 % EC were used to augment the activity of Trichoderma. T. aureoviridae strain S12 was found to be the best among the eight isolates screened for tolerance against the two fungicides and herbicide at a concentration of 10000 - 500 µg respectively as well as against M. phaseolina (Inhibition=72.33 %) in-vitro. This strain showed best compatibility with other strains and highest tolerance to fungicide i.e., Carbendazim 50 % (up to 500 ?g). Highest number (13.7×106) of active spores was recorded at a concentration of 25 ppm of IAA under in-vitro condition. S12 recorded a biocontrol efficiency of 61.8 % against stem rot of jute along with significant plant growth promotion and fibre production. Plant biomass also increased up to 7.5-12.1 % and fibre production 37.0-39.9 % with fungal and bacterial consortium + carbendazim seed dressing and soil drenching. These biocontrol fungi and PGPR consortium with high tolerance to fungicide, weedicide and plant growth regulator up to certain extent may be potentially exploited in IDM which may be a low cost technology in jute and allied fibre crops

    2D Gravity on AdS2AdS_2 with Chern-Simons Corrections

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    We study 2D Maxwell-dilaton gravity with higher order corrections given by the Chern-Simons term. The model admits three distinctive AdS2AdS_2 vacuum solutions. By making use of the entropy function formalism we find the entropy of the solutions which is corrected due to the presence of the Chern-Simons term. We observe that the form of the correction depends not only on the coefficient of the Chern-Simons term, but also on the sign of the electric charge; pointing toward the chiral nature of the dual CFT. Using the asymptotic symmetry of the theory as well as requiring a consistent picture we can find the central charge and the level of U(1) current. Upon uplifting the solutions to three dimensions we get purely geometric solutions which will be either AdS3AdS_3 or warped AdS3AdS_3 with an identification.Comment: 15 pages; V2: refs adde

    Applications of the Collective Field Theory for the Calogero-Sutherland Model

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    We use the collective field theory known for the Calogero-Sutherland model to study a variety of low-energy properties. These include the ground state energy in a confining potential upto the two leading orders in the particle number, the dispersion relation of sound modes with a comparison to the two leading terms in the low temperature specific heat, large amplitude waves, and single soliton solutions. The two-point correlation function derived from the dispersion relation of the sound mode only gives its nonoscillatory asymptotic behavior correctly, demonstrating that the theory is applicable only for the low-energy and long wavelength excitations of the system.Comment: LaTeX, 31 page

    A Farey tale for N=4 dyons

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    We study exponentially suppressed contributions to the degeneracies of extremal black holes. Within Sen's quantum entropy function framework and focusing on extremal black holes with an intermediate AdS3 region, we identify an infinite family of semi-classical AdS2 geometries which can contribute effects of order exp(S_0/c), where S_0 is the Bekenstein-Hawking-Wald entropy and c is an integer greater than one. These solutions lift to the extremal limit of the SL(2,Z) family of BTZ black holes familiar from the "black hole Farey tail". We test this understanding in N=4 string vacua, where exact dyon degeneracies are known to be given by Fourier coefficients of Siegel modular forms. We relate the sum over poles in the Siegel upper half plane to the Farey tail expansion, and derive a "Farey tale" expansion for the dyon partition function. Mathematically, this provides a (formal) lift from Hilbert modular forms to Siegel modular forms with a pole at the diagonal divisor.Comment: 31 page

    Frequency-dependent (ac) Conduction in Disordered Composites: a Percolative Study

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    In a recent paper [Phys. Rev. B{\bf57}, 3375 (1998)], we examined in detail the nonlinear (electrical) dc response of a random resistor cum tunneling bond network (RRTNRRTN, introduced by us elsewhere to explain nonlinear response of metal-insulator type mixtures). In this work which is a sequel to that paper, we consider the ac response of the RRTNRRTN-based correlated RCRC (CRCCRC) model. Numerical solutions of the Kirchoff's laws for the CRCCRC model give a power-law exponent (= 0.7 near p=pcp = p_c) of the modulus of the complex ac conductance at moderately low frequencies, in conformity with experiments on various types of disordered systems. But, at very low frequencies, it gives a simple quadratic or linear dependence on the frequency depending upon whether the system is percolating or not. We do also discuss the effective medium approximation (EMAEMA) of our CRCCRC and the traditional random RCRC network model, and discuss their comparative successes and shortcomings.Comment: Revised and reduced version with 17 LaTeX pages plus 8 JPEG figure
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