9,122 research outputs found

    Community at the Core: A Study of Sarvodaya Nano Finance Limited

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    The paper traces the evolution of Sarvodaya Nano Finance Limited (SNFL). At the outset we explore the background of SNFL, the motivation for the promoters to set up the organisation and how it has grown from the time it was taken over by the community trusts promoted by ASSEFA. As a part of the study, we examine the unique legal structure set up for federating the small SHGs that were widely spread out in the areas of its operation. The idea of federating the SHGs was to leverage the dispersed savings and interest earned on the initial donor resources that were made available to the SHGs at their early stages. The aggregation of these dispersed resources into SNFL enables the women SHGs to mobilise funds from commercial banks and specialised MFI lenders, for an accelerated growth of the movement. The paper examines the rationale for having this structure, its vulnerabilities and the possibilities for growth within the given structure. We argue that this is not a structure that can be replicated easily. We also argue that it cannot grow aggressively in the long run, unless some basic design changes are made. The paper also discusses the basic question on how to structure resources that are given by the donor community for the larger benefit of the poor; and when to bring in the individual stakes of the beneficiaries if one were to promote long lasting institutions. The paper also raises critical questions on governance and management. While appreciating the impressive result achieved by ASSEFA and BASIX in getting a community owned professionally managed institution into being, it also raises questions on whether there are inbuilt mechanisms of carrying forward this effectively in future – given the structuring of capital and rights of each of the constituents.

    Effects on Amorphous Silicon Photovoltaic Performance from High-temperature Annealing Pulses in Photovoltaic Thermal Hybrid Devices

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    There is a renewed interest in photovoltaic solar thermal (PVT) hybrid systems, which harvest solar energy for heat and electricity. Typically, a main focus of a PVT system is to cool the photovoltaic (PV) cells to improve the electrical performance, however, this causes the thermal component to under-perform compared to a solar thermal collector. The low temperature coefficients of amorphous silicon (a-Si:H) allow for the PV cells to be operated at higher temperatures and are a potential candidate for a more symbiotic PVT system. The fundamental challenge of a-Si:H PV is light-induced degradation known as the Staebler-Wronski effect (SWE). Fortunately, SWE is reversible and the a-Si:H PV efficiency can be returned to its initial state if the cell is annealed. Thus an opportunity exists to deposit a-Si:H directly on the solar thermal absorber plate where the cells could reach the high temperatures required for annealing. In this study, this opportunity is explored experimentally. First a-Si:H PV cells were annealed for 1 hour at 100\degreeC on a 12 hour cycle and for the remaining time the cells were degraded at 50\degreeC in order to simulate stagnation of a PVT system for 1 hour once a day. It was found that, when comparing the cells after stabilization at normal 50\degreeC degradation, this annealing sequence resulted in a 10.6% energy gain when compared to a cell that was only degraded at 50\degreeC

    Dynamics of interacting quintessence

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    In this paper, we investigate coupled quintessence with scaling potential assuming specific forms of the coupling as AA namely, αρm˙\alpha \dot{\rho_m}, βρϕ˙\beta \dot{\rho_{\phi}} and σ(ρm˙+ρϕ˙)\sigma (\dot{\rho_m}+\dot{\rho_{\phi}}), and present phase space analysis for three different interacting models. We focus on the attractor solutions that can give rise to late time acceleration with ΩDE/ΩDM\Omega_{DE}/\Omega_{DM} of order unity in order to alleviate the coincidence problem.Comment: 11 pages, 3 figures, matches with the published versio

    Resisting antimicrobial resistance: lessons from fungus farming ants

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    Attine ants use antimicrobials produced by commensal bacteria to inhibit parasites on their fungal gardens. However, in this agricultural system, antimicrobial use does not lead to overwhelming resistance, as is typical in clinical settings. Mixtures of continually evolving antimicrobial variants could support these dynamics. [Abstract copyright: Copyright © 2019 Elsevier Ltd. All rights reserved.

    Dynamics of coupled phantom and tachyon fields

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    In this paper, we apply the dynamical analysis to a coupled phantom field with scaling potential taking particular forms of the coupling (linear and combination of linear), and present phase space analysis. We investigate if there exist late time accelerated scaling attractor that has the ratio of dark energy and dark matter densities of the order one. We observe that the scrutinized couplings cannot alleviate the coincidence problem, however acquire stable late time accelerated solutions. We also discuss coupled tachyon field with inverse square potential assuming linear coupling.Comment: 16 pages, 6 caption figures, 3 Tables, text, figure are added, matches with the published versio

    DC field induced enhancement and inhibition of spontaneous emission in a cavity

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    We demonstrate how spontaneous emission in a cavity can be controlled by the application of a dc field. The method is specially suitable for Rydberg atoms. We present a simple argument for the control of emission.Comment: 3-pages, 2figure. accepted in Phys. Rev.

    Enhanced grain surface effect on magnetic properties of nanometric La0.7Ca0.3MnO3 manganite : Evidence of surface spin freezing of manganite nanoparticles

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    We have investigated the effect of nanometric grain size on magnetic properties of single phase, nanocrystalline, granular La0.7Ca0.3MnO3 (LCMO) sample. We have considered core-shell structure of our LCMO nanoparticles, which can explain its magnetic properties. From the temperature dependence of field cooled (FC) and zero-field cooled (ZFC) dc magnetization (DCM), the magnetic properties could be distinguished into two regimes: a relatively high temperature regime T > 40 K where the broad maximum of ZFC curve (at T = Tmax) is associated with the blocking of core particle moments, whereas the sharp maximum (at T = TS) is related to the freezing of surface (shell) spins. The unusual shape of M (H) loop at T = 1.5 K, temperature dependent feature of coercive field and remanent magnetization give a strong support of surface spin freezing that are occurring at lower temperature regime (T < 40 K) in this LCMO nanoparticles. Additionally, waiting time (tw) dependence of ZFC relaxation measurements at T = 50 K show weak dependence of relaxation rate [S(t)] on tw and dM/dln(t) following a logarithmic variation on time. Both of these features strongly support the high temperature regime to be associated with the blocking of core moments. At T = 20 K, ZFC relaxation measurements indicates the existence of two different types of relaxation processes in the sample with S(t) attaining a maximum at the elapsed time very close to the wait time tw = 1000 sec, which is an unequivocal sign of glassy behavior. This age-dependent effect convincingly establish the surface spin freezing of our LCMO nanoparticles associated with a background of superparamagnetic (SPM) phase of core moments.Comment: 41 pages, 10 figure

    Indications of superconductivity in doped highly oriented pyrolytic graphite

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    We have observed possible superconductivity using standard resistance vs. temperature techniques in phosphorous ion implanted Highly Oriented Pyrolytic Graphite. The onset appears to be above 100 K and quenching by an applied magnetic field has been observed. The four initial boron implanted samples showed no signs of becoming superconductive whereas all four initial and eight subsequent samples that were implanted with phosphorous showed at least some sign of the existence of small amounts of the possibly superconducting phases. The observed onset temperature is dependent on both the number of electron donors present and the amount of damage done to the graphene sub-layers in the Highly Oriented Pyrolytic Graphite samples. As a result the data appears to suggest that the potential for far higher onset temperatures in un-damaged doped graphite exists.Comment: 7 pages, 1 table, 5 figures, 11 references, Acknowledgments section was correcte

    Generation of a superposition of multiple mesoscopic states of radiation in a resonant cavity

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    Using resonant interaction between atoms and the field in a high quality cavity, we show how to generate a superposition of many mesoscopic states of the field. We study the quasi-probability distributions and demonstrate the nonclassicality of the superposition in terms of the zeroes of the Q-function as well as the negativity of the Wigner function. We discuss the decoherence of the generated superposition state. We propose homodyne techniques of the type developed by Auffeves et al [Phys. Rev. Lett. 91, 230405 (2003)] to monitor the superposition of many mesoscopic states.Comment: submitted to Phys. Rev.
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