Cosigned Or Group Loans

We analyze lending contracts when social sanctions are used to enforce repayments and borrowers differ in their unobserved sanctioning abilities. Symmetric group loans are preferred to cosigned loans when borrowers are relatively equal, and cosigned loans are preferred when borrowers are unequal. This explains why microlenders that target the poor (e.g., the Grameen Bank) use symmetric group loans while other untargeted lenders use cosigned loans. Complicated menus of loan contracts that induce borrowers to self select can do no better than these simple loan contracts unless borrowers are very productive. In particular, we explain why group lending arrangements offering different loan terms to members of the same group are seldom observed.Microcredit, Social Sanctions, Grameen Bank

Financial Fragmentation despite Arbitrage

If there were no impediments to the flow of capital across space, then interest rates would equalized. We provide evidence to the contrary. We find significant differences in interest rates across the South Indian state of Tamil Nadu, i.e. evidence that financial markets are fragmented. We also find evidence of limited arbitrage across financial markets. --credit constraints,informal finance

Cosigners Help

We investigate how well social collateral does as an alternative to traditional physical collateral. We do so by studying cosigned loans - a borrower´s loan is backed by the personal guarantee of a cosigner. We use a regression discontinuity approach with data from South Indian bidding Roscas. Our main finding is that cosigners do indeed provide social collateral: doubling the number of cosigners halves the probability of arrears for high risk borrowers. We then distinguish between different theories of social collateral. Cosigners may be e¤ective as a monitoring device (a borrower would pay to rid herself of the nuisance of a cosigner) or as an insurance device (a borrower would pay for the benefit of a cosigner). We show that these two interpretations of cosigning have different empirical predictions in the context of a bidding Roscas. We find support for the insurance role of cosigners. --credit,default,cosigner,rosca

Lepton number violation in Little Higgs model

In this note we examine the constraints imposed by muon anomalous magnetic moment ($(g-2)_\mu$) and $\mu^- \to e^+ e^- e^-$ on lepton number violating (LNV) couplings of the triplet Higgs in Little Higgs (LH) model.Comment: revtex4.0 file, 5 pages including 8 eps figures, version to appear in Phys. Rev.

Does Microcredit Reach the Poor and Vulnerable? Evidence from Northern Bangladesh

Subsidized loans have a history of being diverted to the rich. Yet recently microcredit programs, such as the Grameen Bank in Bangladesh, have become popular among donors and governments as a way to channel funds to the poor. This paper uses a unique panel dataset from two Bangladeshi villages to test if the modern microcredit movement is different from its predecessors. Poverty is measured by levels of consumption. Vulnerability is measured as fluctuations in consumption associated with inefficient risk sharing. We find that subsidized credit is largely successful at reaching the poor and vulnerable. The probability that a microcredit member is below the poverty line is substantially higher than that of a randomly picked household in both villages. In the village where female headed households were found to be vulnerable, nearly half of the female headed households belonged to microcredit programs yet only a quarter of male headed households were microcredit members. While restricting loans to the landless is not effective in reaching the poor and vulnerable, targeting female headed households is.

Little Higgs model effects at γγ collider

Though the predictions of the standard model (SM) are in excellent agreement with experiments there are still several theoretical problems, such as fine-tuning and the hierarchy problem. These problems are associated with the Higgs sector of the SM, where it is widely believed that some "new physics" will take over at the TeV scale. One beyond the SM theory which resolves these problems is the little Higgs model. In this work we shall investigate the effects of the little Higgs model on γγ→γγ scattering, where the process γγ→γγ at high energies occurs in the SM through diagrams involving W, charged quark, and lepton loops (and is, therefore, particularly sensitive to any new physics)

Little Higgs model effects in γγ→γγ\gamma \gamma \to \gamma \gamma

Though the predictions of the Standard Model (SM) are in excellent agreement with experiments there are still several theoretical problems associated with the Higgs sector of the SM, where it is widely believed that some ``{\it new physics}'' will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we have investigated the effects of the LH model on \gggg scattering \cite{Choudhury:2006xa}.Comment: Talk given at LCWS06, Bangalore, 4 pages (style files included

Are weak vector bosons composite?

Recent CERN pp̅ collider data on anomalous Zo events suggest, among other possibilities, a composite structure for the weak intermediate vector bosons. We present a short review of these developments and examine how far the scenario for weak interactions with such composite models of the weak vector bosons presents a viable alternative to the standard electroweak theory. In particular, we show how the scale of the dynamics underlying the composite structure is set by the magnitude of the weak mixing angle sin2θw and point out the possibility of accommodating the anomalous Zo-ll̅γ decay events presently observed within this picture

Constraints on Astro-unparticle Physics from SN 1987A

SN 1987A observations have been used to place constraints on the interactions between standard model particles and unparticles. In this study we calculate the energy loss from the supernovae core through scalar, pseudo scalar, vector, pseudo vector unparticle emission from nuclear bremsstrahlung for degenerate nuclear matter interacting through one pion exchange. In order to examine the constraints on $d_{\cal U}=1$ we considered the emission of scalar, pseudo scalar, vector, pseudo vector and tensor through the pair annihilation process $e^+e^-\to {\cal U} \gamma$. In addition we have re-examined other pair annihilation processes. The most stringent bounds on the dimensionless coupling constants for $d_{\cal U} =1$ and $\Lambda_{\cal U}= m_Z$ are obtained from nuclear bremsstrahlung process for the pseudo scalar and pseudo-vector couplings $\bigl|\lambda^{\cal P}_{0,1}\bigr|\leq 4\times 10^{-11}$ and for tensor interaction, the best limit on dimensionless coupling is obtained from $e^+ e^-\to {\cal U} \gamma$ and we get $\bigl|\lambda^{\cal T}\bigr| \leq 6\times 10^{-6}$.Comment: 12 pages, 2 postscript figure

A Rapid Decision Sampling Plan for Implementing Area—Wide Management of the Red Palm Weevil, Rhynchophorus ferrugineus, in Coconut Plantations of India

The red palm weevil Rhynchophorus ferrugineus Olivier (Curculionidae/Rhynchophoridae/Dryophthoridae) is a lethal pest of young coconut palms, Cocos nucifera L. (Arecales: Arecaceae), with a highly aggregated population distribution pattern. R. ferrugineus is managed in several coconut growing countries using area-wide pheromone based programmes that need a substantial commitment of funds over a period of time. Often, decisions to implement area-wide management of R. ferrugineus are based on pheromone trap captures in surveillance traps and or infestation reports. Implementing area-wide management of this pest on the basis of such data can be inaccurate, as it may either under or over estimate the pest intensity in the field. This study presents sampling plans for rapid and accurate classification of R. ferrugineus infestation in coconut plantations of India by inspecting palms to detect infestation in a sequence until a decision to either implement or not to initiate area-wide management of R. ferrugineus can be made. The sampling plans are based on a common aggregation index of 3.45, assumed action threshold values of either 1.0 (plan A) or 0.5 (plan B) per cent infested palms and a risk factor of making the wrong decision set at 0.05. Using plans A and B, if the cummulative number of infested palms in a young 1 hectare coconut plantation is zero out of 150 palms for both plans, then area-wide management is not required, while on the other hand, if the cummulative number of infested palms for the same area is 6 (plan A), or 5 (plan B), then area-wide management of R. ferrugineus is essential. The proposed sampling plans are efficient tools in decision making, particularly at very low and high levels of infestation and can also be used to assess the performance of R. ferrugineus IPM programmes that are in progress. These plans not only save time and money as only a small area needs to be sampled to arrive at a correct decision, but are also efficient in rating the infestation level accurately