67,775 research outputs found
The financial sustainability of Microcredit in Portugal
Microcredit and microfinance emerged in the 1970’s in Bangladesh and other developing countries and expanded rapidly worldwide as a business model financially sustainable and able to fight poverty and social exclusion. Empirical evidence confirms microcredit ability to mitigate poverty but its financial sustainability is controversial. Using 2006-2009 Portuguese micro-level data, we estimate the failure rate of Portuguese micro-credit projects as 20,6%/year that, to be financially sustainable, would require a real interest rate by 25%/year. Using a territorial variable on a discrete Cox proportional hazard model with censured data, we estimate that the failure rate of those micro-credit projects located in the worst-case NUTS II Portuguese regions (Alentejo and Centro) and promoted by lower schooling people is significantly higher than best-case.Microcredit, Firms failure rate, Poverty, Financial sustainability
Information entropy of classical versus explosive percolation
We study the Shannon entropy of the cluster size distribution in classical as
well as explosive percolation, in order to estimate the uncertainty in the
sizes of randomly chosen clusters. At the critical point the cluster size
distribution is a power-law, i.e. there are clusters of all sizes, so one
expects the information entropy to attain a maximum. As expected, our results
show that the entropy attains a maximum at this point for classical
percolation. Surprisingly, for explosive percolation the maximum entropy does
not match the critical point. Moreover, we show that it is possible determine
the critical point without using the conventional order parameter, just
analysing the entropy's derivatives.Comment: 6 pages, 6 figure
Limits on dark matter proton scattering from neutrino telescopes using micrOMEGAs
Limits on dark matter spin dependent elastic scattering cross section on
protons derived from IceCube data are obtained for different dark matter
annihilation channels using micrOMEGAs. The uncertainty on the derived limits,
estimated by using different neutrino spectra, can reach a factor two. For all
dark matter annihilation channels except for quarks, the limits on the spin
dependent cross section are more stringent than those obtained in direct
detection experiments. The new functions that allow to derive those limits are
described.Comment: 23 pages, 7 figures; v2: references added; v3 and v4: clarifications
added; The code can be downloaded from https://lapth.cnrs.fr/micromega
Strong Reduction of the Field-Dependent Microwave Surface Resistance in YBCO with BaZrO_3 Inclusions
We present measurements of the magnetic field dependent microwave surface
resistance in laser-ablated YBaCuO films on SrTiO
substrates. BaZrO crystallites were included in the films using composite
targets containing BaZrO inclusions with mean grain size smaller than 1
m. X-ray diffraction showed single epitaxial relationship between
BaZrO and YBaCuO. The effective surface resistance was
measured at 47.7 GHz for 6090 K and 00.8 T. The magnetic
field had a very different effect on pristine YBaCuO and
YBaCuO/BaZrO, while for 0 only a reduction of
in the YBaCuO/BaZrO film was observed,
consistent with dc measurements. At low enough , in moderate fields
YBaCuO/BaZrO exhibited an intrinsic thin film
resistance lower than the pure film. The results clearly indicate that
BaZrO inclusions determine a strong reduction of the field-dependent
surface resistance. From the analysis of the data in the framework of simple
models for the microwave surface impedance in the mixed state we argue that
BaZrO inclusions determine very steep pinning potentials.Comment: LaTeX, 6 pages, 4 figures, uses jpconf.cls and jpconf11.clo class
files, talk given at EUCAS 2007, submitted to J. Phys.: Conf. Serie
- …