8,009 research outputs found
HIV/AIDS and time allocation in rural Malawi
AIDS morbidity and mortality are expected to have a large impact on households’ labor supply in rural Malawi since they reduce the time that adults can spend on production for subsistence and on income generating activities. However, the data demands for estimating this impact are high, limiting the amount of empirical evidence. In this paper, we utilize a unique combination of quantitative and qualitative data, including biomarkers for HIV, collected by the Malawi Diffusion and Ideational Change Project, to analyze the impact of AIDS-related morbidity and mortality on time allocation decisions for rural Malawians. We evaluate both the direct effect of HIV/AIDS on the time allocation of affected individuals as well as its indirect effect on the time allocation of surviving household members. We find that the latter is the most important effect of AIDS-related morbidity and mortality, especially on women’s time. Specifically, AIDS induces diversification of income sources, with women reallocating their time from work-intensive (typically farming and heavy chores) to cash-generating tasks (such as casual labor).Africa, AIDS/HIV, economic impact, Malawi, time allocation
Double Parton Scatterings in High-Energy Proton-Nucleus Collisions and Partonic Correlations
The joint study of Double Parton Scatterings, in high energy proton-proton
and proton-nucleus collisions, can provide a lot of information on multi-parton
correlations. The multi-parton structure is in fact probed in a different way
by DPS, in - and in - collisions. In - collisions the
interpretation of the experimental results may be however complicated by the
presence of interference terms, which are missing in -. A suitable
reaction channel, where interference terms are absent, is production. By
studying production in - collisions, we estimate that the fraction
of events due to DPS may be larger by a factor 3 or 4, as compared to -,
while the amount of the increased fraction can give a direct indication on the
importance of different correlation terms.Comment: 27 pages, 9 figure
Radio recombination lines from obscured quasars with the SKA
We explore the possibility of detecting hydrogen radio recombination lines
from 0 < z < 10 quasars. We compute the expected Hnalpha flux densities as a
function of absolute magnitude and redshift by considering (i) the range of
observed AGN spectral indices from UV to X-ray bands, (ii) secondary
ionizations from X-ray photons, and (iii) stimulated emission due to nonthermal
radiation. All these effects are important to determine the line fluxes. We
find that the combination of slopes: alpha_X,hard = -1.11, alpha_X,soft = -0.7,
alpha_EUV = -1.3, alpha_UV = -1.7, maximizes the expected flux, f_Hnalpha = 10
microJy for z = 7 quasars with M_AB = -27 in the n = 50 lines; allowed SED
variations produce variations by a factor of 3 around this value. Secondaries
boost the line intensity by a factor of 2 to 4, while stimulated emission in
high-z quasars with M_AB = -26 provides an extra boost to RRL flux observed at
nu = 1 GHz if recombinations arise in HII regions with T_e = 10^3-5 K, n_e =
10^3-5 cm^-3. We compute the sensitivity required for a 5sigma detection of
Hnalpha lines using the SKA, finding that the SKA-MID could detect sources with
M_AB < -27 (M_AB < -26) at z < 8 (z < 3) in less than 100 hrs of observing
time. These observations could open new paths to searches for obscured SMBH
progenitors, complementing X-ray, optical/IR and sub-mm surveys.Comment: 11 pages, 9 figures; to be published in Monthly Notices of the Royal
Astronomical Society Main Journa
(Co)homology of crossed modules with coefficients in a -module
We define a cotriple (co)homology of crossed modules with coefficients in a
-module. We prove its general properties, including the connection with
the existing cotriple theories on crossed modules. We establish the
relationship with the (co)homology of the classifying space of a crossed module
and with the cohomology of groups with operators. An example and an application
are given.Comment: 32 pages, LaTeX2e, Paul Taylor's diagram package; added reference.
Accepted for publication by Homology, Homotopy and Application
Nanoparticles of transition metals oxides with application potential
Tato práce se zabĂ˝vá nejvĂce pouĹľĂvanĂ˝mi metodami pĹ™Ăpravy a fyzikálnĂmi vlastnostmi nanočástic pĹ™echodnĂ˝ch kovĹŻ. FyzikálnĂ vlastnosti nanočástic mohou bĂ˝t kontrolovány pomocĂ velikosti a tvaru částic. Na velikost částic majĂ vliv podmĂnky pĹ™Ăpravy. ZabĂ˝vali jsme se pĹ™edevšĂm sol-gelovou metodou, ko-precipitacĂ a mikroemulzĂ a provedli jsme shrnutĂ fyzikálnĂch vlastnostĂ ZrO2, TiO2, CoFe2O4, kterĂ© jsou dĹŻleĹľitĂ˝m aspektem pro jejich moĹľnĂ© budoucĂ vyuĹľitĂ. Vzorky nanočástic kobaltovĂ˝ch ferritĹŻ zapoudĹ™enĂ˝ch v SiO2 matrici, kterĂ© byly pĹ™ipraveny pomocĂ modifikovanĂ© sol-gelovĂ© metody, byly charakterizovány pomocĂ rentgenovĂ© difrakce a ICP-OES. Byla urÄŤena velikost částic, která byla porovnána s finálnĂ ĹľĂhacĂ teplotou.We present summary of the most used preparation methods and physical properties of transition metal-based nanoparticles. The physical properties of the nanoparticles can be controlled by particle shape and size that can be affected by conditions of preparation. We mainly described the sol-gel method, co-precipitation and microemulsions method. We summarized physical properties of ZrO2, TiO2 and CoFe2O4 with respect to their possible application. A series of the cobalt ferrite nanoparticles embedded in silica matrix, obtained by modified sol-gel route, was characterized using X-ray diffraction and ICP-OES. We determined the particle diameter and compared them to the final annealing temperature.Ăšstav aplikovanĂ© matematiky a fyzikyDokonÄŤená práce s Ăşspěšnou obhajobo
Spectrum of a family of operators
Having as start point the classic definitions of resolvent set and spectrum
of a linear bounded operator on a Banach space, we introduce the resolvent set
and spectrum of a family of linear bounded operators on a Banach space. In
addition, we present some results which adapt to asymptotic case the classic
results.Comment: 23 page
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