16,826 research outputs found

    The Effects of the Type and Timing of Dietary Folate on Memory, Learning, and Gene Expression in Mice

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    Folate has been known as an important vitamin for several decades. It is vital in development and epigenetics and is especially known for its involvement in the prevention of neural tube defects in newborns. Due to this ability, a synthetic form of folate, folic acid, was mandated by the government to be reinforced into cereals and grains. This study used a mouse model to determine the effects folic acid and 5-methyltetrahydrofolate have on gene expression and behavior. Since folate is known to be important for epigenetics and neuronal development, this study examined the effects of folate by applying behavioral tests to test memory and learning and a microarray analysis to test for gene expression changes. It was confirmed that folate is important for properly functioning cognition in mice. Additionally, the microarray analysis showed clear gene expression changes between the folate replete mice and the folate deficient mice. Interestingly, it was observed that the natural form of folate, 5-methyltetrahydrofolate, may confer long term benefits compared to the synthetic form, although additional research is needed to confirm this

    Computer-Assisted Program Reasoning Based on a Relational Semantics of Programs

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    We present an approach to program reasoning which inserts between a program and its verification conditions an additional layer, the denotation of the program expressed in a declarative form. The program is first translated into its denotation from which subsequently the verification conditions are generated. However, even before (and independently of) any verification attempt, one may investigate the denotation itself to get insight into the "semantic essence" of the program, in particular to see whether the denotation indeed gives reason to believe that the program has the expected behavior. Errors in the program and in the meta-information may thus be detected and fixed prior to actually performing the formal verification. More concretely, following the relational approach to program semantics, we model the effect of a program as a binary relation on program states. A formal calculus is devised to derive from a program a logic formula that describes this relation and is subject for inspection and manipulation. We have implemented this idea in a comprehensive form in the RISC ProgramExplorer, a new program reasoning environment for educational purposes which encompasses the previously developed RISC ProofNavigator as an interactive proving assistant.Comment: In Proceedings THedu'11, arXiv:1202.453


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    The most common indicator of the financial performance of development finance institutions, the Subsidy Dependence Index of Yaron (1992a), fails to recognize that subsidies are like equity injections whose use over time has a cost. Thus, the SDI underestimates subsidy. This paper gives a modified framework that counts all subsidies as equity injections. The paper also recasts the traditional SDI formula to clarify its definition and to show its invariance with respect to the form of subsidized resources. The modified framework is applied to the Grameen Bank in Bangladesh and to Caja los Andes, a microfinance organization in Bolivia. The underestimation of the traditional measure is material. The modified framework could be applied to any subsidized organization.Financial Economics,


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    This paper suggests ways donors can help the evolution of sustainable microfinance organizations. Sustainability is good because it helps MFOs help more poor people than otherwise. Sustainability is hard because it requires balancing outreach and sustainability with prices the poor can afford yet high enough to cover the costs of the MFO. Donors are like genetic engineers whose job is to speed the evolution of sturdy MFOs. Technical assistance is the best way to tinker with MFOs.Financial Economics,

    A Scoring Model of the Risk of Costly Arrears at a Microfinance Lender in Bolivia

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    Can scoring models help microfinance lenders in poor countries as much as they have helped credit-card lenders in rich countries? I model the probability that loans from a microlender in Bolivia had arrears of 15 days or more. Although arrears in microfinance depend on many factors difficult to include in statistical models, I find that inexpensive data does indeed have some predictive power. In microfinance, computer models will not replace loan officers, but they can flag the highest risks and act as a cross-check on human judgement.Scoring,risk management,credit risk,Bolivia,microfinance


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    Meta-rules, or rules for making rules, determine the costs of innovation and thus the pace of economic growth. Adapting rules to a changing economic environment through explicit, well-designed meta- rules makes economic growth quicker, less painful, and more certain than adapting rules through chance-based evolution.Research and Development/Tech Change/Emerging Technologies,

    Evaluation and Microenterprise Programs

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    Microenterprise programs attempt to help poor people start or strengthen small businesses. Funding and political support has grown rapidly. Is microenterprise a good use of scarce development funds? Unfortunately, most evaluations have been case studies in what not to do. Because benefits and costs cannot be measured completely nor with perfect certainty, rigorous evaluations should support their necessarily subjective judgements with logic and explicit assumptions. The usefulness of an evaluation lies not in its (apparent) incontrovertibility but rather in its clarity of assumptions and in its openness to meaningful review and critique.Microenterprise,evaluation,welfare reform

    Scoring Drop-Out at a Microlender in Bolivia

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    This paper presents a scoring model that predicts the risk of drop-out for borrowers at a microfinance lender in Bolivia. Drop-out risk was greater for women, manufacturers, newer borrowers, and those with more arrears. Out-of-sample tests suggest that scoring may help microfinance lenders to detect segments of their clientele (and even specific current clients) who are at-risk of drop-out.Scoring,credit risk,risk management,financial institutions,microfinance
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