4,869 research outputs found
The triangle of microfinance
The initial success of microfinance programs in the 1970s led pioneers to think that many essential problems of the poor might be resolved by access to credit alone the ability to acquire assets, to start businesses, to finance emergency needs and to insure against illness and disaster. Part of that vision has certainly been realized. But much remains to be done. Most microfinance institutions (MFIs) are still small and vulnerable to constraints on their resources and to the risks inherent in single-issue portfolios. Most depend upon donors and governments to remain in operation. There is much waste and duplication, and some mature programs have declining loan recovery rates, even as competition for borrowers rises from conventional banks and finance companies. Analyzing the failures of credit programs aimed at small farmers and the successes of other programs showed the need for new understanding of the ways that poor households make spending, borrowing, and saving decisions. This area was previously neglected in policymaking on food security issues. The International Food Policy Research Institute (IFPRI) supported household surveys in nine Asian and African countries during the 1990s that analyzed formal and informal financial transactions, and it also evaluated the success of innovative approaches at some MFIs. The overall goal was to clarify the conditions under which state investment in microfinance programs might improve life for poor people more than state investment of the same funds in education, health, nutrition, or infrastructure development. The research led to the concept of the "critical triangle of microfinance" the need for any MFI to manage simultaneously the problems of outreach (reaching the poor both in terms of numbers and depth of poverty), financial sustainability (meeting operating and financial costs over the long term), and impact (having discernible effect upon clients' quality of life). This book elaborates on these objectives and shows that the most successful MFIs expand all sides of that triangle. Tradeoffs are sometimes inevitable, but even so, synergies among the three make the concept valuable from Author's Abstract.Microfinance ,
Precision electroweak tests with scattering
Measurements of the cross section for elastic scattering
with unprecedented precision have recently been proposed. The impact of these
experiments for detecting possible deviations from the standard electroweak
theory is analyzed and compared with that of several other measurements.Comment: 4 pages, 1 figure. To be published in Phys. Rev. D, Brief Reports.
Misprints correcte
Understanding the Forward Muon Deficit in Coherent Pion Production
For any inelastic process with ,
the cross section at is given by Adler's PCAC theorem.
Inclusion of the lepton mass has a dynamical effect (``PCAC-screening'') caused
by interference of spin-zero () and spin-one exchanges. This effect may
be relevant to the forward suppression reported in recent experiments.Comment: 3 pages, 2 figures, presented at NuInt07, Fermilab, may 31 - june 3
200
Auger electron spectroscopy study of oxidation of a PdCr alloy used for high-temperature sensors
A Pd-13 wt. percent Cr solid solution is a promising high-temperature strain gage alloy. In bulk form it has a number of properties that are desirable in a resistance strain gage material, such as a linear electrical resistance versus temperature curve to 1000 C and stable electrical resistance in air at 1000 C. However, unprotected fine wire gages fabricated from this alloy perform well only to 600 C. At higher temperatures severe oxidation degrades their electrical performance. In this work Auger electron spectroscopy was used to study the oxidation chemistry of the alloy wires and ribbons. Results indicate that the oxidation is caused by a complex mechanism that is not yet fully understood. As expected, during oxidation, a layer of chromium oxide is formed. This layer, however, forms beneath a layer of metallic palladium. The results of this study have increased the understanding of the oxidation mechanism of Pd-13 wt. percent Cr
Flight evaluation of modifications to a digital electronic engine control system in an F-15 airplane
The third phase of a flight evaluation of a digital electronic engine control system in an F-15 has recently been completed. It was found that digital electronic engine control software logic changes and augmentor hardware improvements resulted in significant improvements in engine operation. For intermediate to maximum power throttle transients, an increase in altitude capability of up to 8000 ft was found, and for idle to maximum transients, an increase of up to 4000 ft was found. A nozzle instability noted in earlier flight testing was investigated on a test engine at NASA Lewis Research Center, a digital electronic engine control software logic change was developed and evaluated, and no instability occurred in the Phase 3 flight evaluation. The backup control airstart modification was evaluated, and gave an improvement of airstart capability by reducing the minimum airspeed for successful airstarts by 50 to 75 knots
Lifetime reduction of surface states at Cu, Ag and Au(111) caused by impurity scattering
We present density-functional results on the lifetime of the (111) surface
state of the noble metals. We consider scattering on the Fermi surface caused
by impurity atoms belonging to the 3d and 4sp series. The results are analyzed
with respect to film thickness and with respect to separation of scattering
into bulk or into surface states. While for impurities in the surface layer the
overall trends are similar to the long-known bulk-state scattering, for
adatom-induced scattering we find a surprising behavior with respect to the
adatom atomic number. A plateau emerges in the scattering rate of the 3d
adatoms, instead of a peak characteristic of the d resonance. Additionally, the
scattering rate of 4sp adatoms changes in a zig-zag pattern, contrary to a
smooth parabolic increase following Linde's rule that is observed in bulk. We
interpret these results in terms of the weaker charge-screening and of
interference effects induced by the lowering of symmetry at the surface
Shear bond strengths of seven self-etching primers after thermo-cycling
Objective: Self-etching primers are widely used in restorative dentistry. However, only one primer has been developed for orthodontic applications. The objective of this study was to assess the suitabiliy of restorative self-etching primers on unabraded enamel. Material and Methods: Seven self-etching primers (Transbond™ SEP +, Xeno®III, Clearfil™SE, Futurabond®NR, OneCoat, M-Bond and OptiBond®) were compared with two conventionally-etched control groups (Transbond™ MIP). All groups with the exception of one of the two control groups underwent thermo-cycling (1000x, 5-55°C). Bovine teeth stored in physiological saline solution were used for the purpose of this study. Results: Both before and after thermo-cycling, the control groups presented very similar shear strengths which did not differ significantly from each other or from the Transbond™ SEP +  and Clearfil™SE specimens. During thermo-cycling, all groups except the control group and the Transbond™ SEP +  specimens displayed losses from the shear bodies. These losses occurred on all of the OptiBond® samples. The adhesive remnant index (ARI) and enamel tear-outs correlated closely with the adhesive values. Conclusions: Our adhesive value assessments support the conclusion that only Transbond™ SEP +  and Clearfil™SE can be recommended for clinical us
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