1,282 research outputs found
Exploring the effects of health shocks on antipoverty interventions : experience of poor beneficiary households in Bangladesh
How and whether health shocks impact poverty reduction interventions remains a largely unexplored topic to which not much attention has been paid. This study explored whether and how health shocks affect anti-poverty interventions targeted to extremely poor households using data from 8 focus group discussions and 12 case studies. Those in extremely poor households mostly experienced episodes of chronic disease that incurred greater health-care costs, largely financed by the out-of-pocket payment system. The majority of those from poor households met health-care costs by selling their means of livelihood, borrowing cash, and marketing physical assets. This study argues that livelihood support alone is likely to be insufficient to reduce poverty. Health needs, subsequently, should be prioritized while designing an anti-poverty program
Thermal Re-emission Model
Starting from a continuum description, we study the non-equilibrium
roughening of a thermal re-emission model for etching in one and two spatial
dimensions. Using standard analytical techniques, we map our problem to a
generalized version of an earlier non-local KPZ (Kardar-Parisi-Zhang) model. In
2+1 dimensions, the values of the roughness and the dynamic exponents
calculated from our theory go like and in 1+1
dimensions, the exponents resemble the KPZ values for low vapor pressure,
supporting experimental results. Interestingly, Galilean invariance is
maintained althrough.Comment: 4 pages, minor textual corrections and typos, accepted in Physical
Review B (rapid
Level Set Approach to Reversible Epitaxial Growth
We generalize the level set approach to model epitaxial growth to include
thermal detachment of atoms from island edges. This means that islands do not
always grow and island dissociation can occur. We make no assumptions about a
critical nucleus. Excellent quantitative agreement is obtained with kinetic
Monte Carlo simulations for island densities and island size distributions in
the submonolayer regime.Comment: 7 pages, 9 figure
Precision Measurement of the Radiative Decay of the Free Neutron
The standard model predicts that, in addition to a proton, an electron, and
an antineutrino, a continuous spectrum of photons is emitted in the
decay of the free neutron. We report on the RDK II experiment which measured
the photon spectrum using two different detector arrays. An annular array of
bismuth germanium oxide scintillators detected photons from 14 to 782~keV. The
spectral shape was consistent with theory, and we determined a branching ratio
of 0.00335 0.00005 [stat] 0.00015 [syst]. A second detector array
of large area avalanche photodiodes directly detected photons from 0.4 to
14~keV. For this array, the spectral shape was consistent with theory, and the
branching ratio was determined to be 0.00582 0.00023 [stat] 0.00062
[syst]. We report the first precision test of the shape of the photon energy
spectrum from neutron radiative decay and a substantially improved
determination of the branching ratio over a broad range of photon energies
Apolipoprotein E4 influences amyloid deposition but not cell loss after traumatic brain injury in a mouse model of Alzheimer's disease
The epsilon4 allele of apolipoprotein E (APOE) and traumatic brain injury (TBI) are both risk factors for the development of Alzheimer's disease (AD). These factors may act synergistically, in that APOE4+ individuals are more likely to develop dementia after TBI. Because the mechanism underlying these effects is unclear, we questioned whether APOE4 and TBI interact either through effects on amyloid-beta (Abeta) or by enhancing cell death/tissue injury. We assessed the effects of TBI in PDAPP mice (transgenic mice that develop AD-like pathology) expressing human APOE3 (PDAPP:E3), human APOE4 (PDAPP:E4), or no APOE (PDAPP:E-/-). Mice were subjected to a unilateral cortical impact injury at 9-10 months of age and allowed to survive for 3 months. Abeta load, hippocampal/cortical volumes, and hippocampal CA3 cell loss were quantified using stereological methods. All of the groups contained mice with Abeta-immunoreactive deposits (56% PDAPP:E4, 20% PDAPP:E3, 75% PDAPP:E-/-), but thioflavine-S-positive Abeta (amyloid) was present only in the molecular layer of the dentate gyrus in the PDAPP:E4 mice (44%). In contrast, our previous studies showed that in the absence of TBI, PDAPP:E3 and PDAPP:E4 mice have little to no Abeta deposition at this age. After TBI, all of the Abeta deposits present in PDAPP:E3 and PDAPP:E-/- mice were diffuse plaques. In contrast to the effect of APOE4 on amyloid, PDAPP:E3, PDAPP:E4, and PDAPP:E-/- mice did not differ in the amount of brain tissue or cell loss. These data support the hypothesis that APOE4 influences the neurodegenerative cascade after TBI via an effect on Abeta
The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland
Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the spatial and temporal variability of calcium (Ca2+, mainly from mineral dust) and sodium (Na+, mainly from sea salt) deposition. Cores of high common inter-annual variability are grouped with an EOF analysis, resulting in regionally representative Ca2+ and Na+ records for northeastern and central Greenland. Utilizing a regression and validation method with ERA-40 reanalysis data, these common records are associated with distinct regional atmospheric circulation patterns over the North American Arctic, Greenland, and Central to Northern Europe. These patterns are interpreted in terms of transport and deposition of the impurities. In the northeastern part of the GrIS sea salt records reflect the intrusion of marine air masses from southeasterly flow. A large fraction of the Ca2+ variability in this region is connected to a circulation pattern suggesting transport from the west and dry deposition. This pattern is consistent with the current understanding of a predominantly Asian source of the dust deposited over the GrIS. However, our results also indicate that a significant fraction of the inter-annual dust variability in NE and Central Greenland is determined by the frequency and intensity of wet deposition during the season of high atmospheric dust loading, rather than representing the variability of the Asian dust source and/or long-range transport to Greenland. The variances in the regional proxy records explained by the streamfunction patterns are high enough to permit reconstructions of the corresponding regional deposition regimes and the associated circulation pattern
Spiral surface growth without desorption
Spiral surface growth is well understood in the limit where the step motion
is controlled by the local supersaturation of adatoms near the spiral ridge. In
epitaxial thin-film growth, however, spirals can form in a step-flow regime
where desorption of adatoms is negligible and the ridge dynamics is governed by
the non-local diffusion field of adatoms on the whole surface. We investigate
this limit numerically using a phase-field formulation of the
Burton-Cabrera-Frank model, as well as analytically. Quantitative predictions,
which differ strikingly from those of the local limit, are made for the
selected step spacing as a function of the deposition flux, as well as for the
dependence of the relaxation time to steady-state growth on the screw
dislocation density.Comment: 9 pages, 3 figures, RevTe
Spin exchange between charged paramagnetic particles in dilute solutions
© Springer-Verlag Wien 2014. Kinetic equations for the spin density matrix which take into account binary collisions and a method of calculating the spin exchange effective radius have been generalized to the case of dilute solutions of charged paramagnetic particles. The effective radius of the spin exchange and rate constant of the bimolecular spin exchange between charged paramagnetic particles in solutions have been calculated numerically. Calculations have been performed under the assumption that the exchange interaction is isotropic and decays exponentially with the increase in the distance between radicals, and the solution has a given dielectric permittivity and Debye screening radius. Dependences of the spin exchange rate constant on the mutual diffusion coefficient, exchange and electrostatic interactions parameters have been found numerically. The theory has been applied to experimental results taken from the literature. The rate constant of the spin exchange between radicals of like charge found from the experiment and calculated within the developed theory are in good qualitative agreement
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