9,429 research outputs found
Foreign aid and business bottlenecks : a study of aid effectiveness
This paper proposes a new framework to analyze aid effectiveness. Using World Bank firm survey data and OECD aid flow data, the authors analyze whether aid targets areas that firms in developing countries have identified as obstacles for their growth and whether aid actually improves firms'perceptions of those areas. The analysis finds that aid does target the areas that firms have identified as obstacles; aid funding trade related projects is particularly effective in targeting the correct countries. For the most part, aid has a positive impact on improving firms'perceptions, particularly in the business environment. And for each target area, smaller aid disbursements tend to be more effective at improving firm perceptions than larger disbursements.Environmental Economics&Policies,Development Economics&Aid Effectiveness,Disability,Gender and Health,School Health
Mu-tau neutrino refraction and collective three-flavor transformations in supernovae
We study three-flavor collective neutrino transformations in the
dense-neutrino region above the neutrino sphere of a supernova core. We find
that two-flavor conversions driven by the atmospheric mass difference and the
13-mixing angle capture the full effect if one neglects the second-order
difference between the muon and tau neutrino refractive index. Including this
"mu-tau matter term" provides a resonance at a density of approximately 3 x
10^7 g cm^-3 that typically causes significant modifications of the overall
electron neutrino and antineutrino survival probabilities. This effect is
surprisingly sensitive to deviations from maximal 23-mixing, being different
for each octant.Comment: 9 pages, 7 figures. New presentation of results, version to be
published in PR
The Cocoon Nebula and its ionizing star: do stellar and nebular abundances agree?
(Abridged) Main sequence massive stars embedded in an HII region should have
the same chemical abundances as the surrounding nebular gas+dust. The Cocoon
nebula, a close-by Galactic HII region ionized by a narrow line B0.5 V single
star (BD+46 3474), is an ideal target to perform a detailed comparison of
nebular and stellar abundances in the same Galactic HII region. We investigate
the chemical content of O, N and S in the Cocoon nebula from two different
points of view: an empirical analysis of the nebular spectrum and a detailed
spectroscopic analysis of its ionizing B-type star using state-of-the-art
stellar atmosphere modeling. By comparing the stellar and nebular abundances,
we aim to indirectly address the long-standing problem of the discrepancy found
between abundances obtained from collisionally excited lines (CELs) and optical
recombination lines in photoionized nebulae. We collect spatially resolved
spectroscopy of the Cocoon nebula and a high resolution optical spectrum of its
ionizing star. Standard nebular techniques are used to compute the physical
conditions and gaseous abundances of O, N and S. We perform a self-consistent
spectroscopic abundance analysis of BD+46 3474 based on the atmosphere code
FASTWIND to determine the stellar parameters and Si, O, and N abundances. The
Cocoon nebula and its ionizing star, located at a distance of 800+-80 pc, have
a very similar chemical composition as the Orion nebula and other B-type stars
in the solar vicinity. This result agrees with the high degree of homogeneity
of the present-day composition of the solar neighbourhood as derived from the
study of the local cold-gas ISM. The comparison of stellar and nebular CELs
abundances in the Cocoon nebula indicates that O and N gas+dust nebular values
are in better agreement with stellar ones assuming small temperature
fluctuations, of the order of those found in the Orion nebula.Comment: Accepted for publication in A&A. 13 pages, 7 tables and 6 figure
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Regional index of sustainable economic well-being development project: final report
This report presents results from a development project carried out by nef (the new economics foundation) on behalf of emda (the East Midlands Development Agency) and Natural England, to improve the methodologies used in the calculation of the R-ISEW (Regional Index of Sustainable Economic Well-Being)
A holistic approach to the evaluation of sustainable housing
Residential housing is often evaluated against single or at best a limited number of similar criteria. These include quantifiable indicators such as energy use and its associated greenhouse gas emissions. It might also include material consumption from an embodied energy or resource use perspective. Social factors or qualitative indicators may be evaluated but are rarely placed or juxtaposed alongside these quantifiable indicators. A one-dimensional approach will be limiting because sustainable development includes both environmental and social factors. This paper describes the methodologies that have been developed to assess housing developments against five quite different criteria. These are: energy use, resource use, neighbourhood character, neighbourhood connectedness and diversity. In each case, high and low sustainability practice has been identified so that ranking is possible. These methodologies have then been tested by evaluating a typical precinct (approximately 400 m by 400 m) of a 1970-80s housing development in a suburb of Geelong. The rankings of the particular precinct have then been combined in a visual way to assist in the evaluation of the housing in a more holistic way. The results of this evaluation method are presented, along with a discussion of the strengths and weaknesses of the methodologies. The research is the outcome of collaboration by a cross-disciplinary group of academics within Deakin’s School of Architecture and Building
Recent results from the Pierre Auger Observatory
The main results from the Auger Observatory are described. A steepening of
the spectrum is observed at the highest energies, supporting the expectation
that above eV the cosmic ray energies are significantly
degraded by interactions with the CMB photons (the GZK effect). This is further
supported by the correlations observed above eV with the
distribution of nearby active galaxies, which also show the potential of Auger
to start the era of charged particle astronomy. The lack of observation of
photons or neutrinos strongly disfavors top-down models, and these searches may
approach in the long term the sensitivity required to test the fluxes expected
from the secondaries of the very same GZK process. Bounds on the anisotropies
at EeV energies contradict hints from previous experiments that suggested a
large excess from regions near the Galactic centre or the presence of a dipolar
type modulation of the cosmic ray flux.Comment: 6 p., 8 figs., proceedings of the XXIII International Conference on
Neutrino Physics and Astrophysics (Neutrino 08
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