965 research outputs found
The Impact of Health Disparities on COVID-19 Outcomes: Early Findings from a High-Income Country and Two Middle-Income Countries
The SARS-CoV-2 infection, which causes the coronavirus disease (COVID-19), has affected lives, with very adverse outcomes
in specific populations in the United States of America (USA), a high-income country, and two middle-income countries, Brazil
and South Africa. This paper aims to discuss the relationship of race/ethnicity with COVID-19-associated factors in the three
countries. The information is based on data collected from infectious disease/epidemiological centers in the USA, Brazil, and
South Africa. Adverse COVID-19 outcomes have been associated with the burden of exposure and disease, linked to socioeconomic
determinants, among specific ethnicities in all three countries. The prevalence of comorbidities before and the likelihood
of work-related exposure in the context of COVID-19 infection puts ethnic minorities in the USA and some ethnic majorities and
minorities in Brazil and South Africa at greater risk. We envisage that this work will contribute to ongoing discussions related to
addressing socioeconomic determinants of health, and the need for stakeholders in various sectors to work on addressing
observed health disparities for overall improvement in health and healthcare given the current pandemic
Solar sail capture trajectories at Mercury
Mercury is an ideal environment for future planetary exploration by solar sail since it has proved difficult to reach with conventional propulsion and hence remains largely unexplored. In addition, its proximity to the Sun provides a solar sail acceleration of order ten times the sail characteristic acceleration at 1 AU. Conventional capture techniques are shown to be unsuitable for solar sails and a new method is presented. It is shown that capture is bound by upper and lower limits on the orbital elements of the approach orbit and that failure to be within limits results in a catastrophic collision with the planet. These limits are presented for a range of capture inclinations and sail characteristic accelerations. It is found that sail hyperbolic excess velocity is a critical parameter during capture at Mercury, with only a narrow allowed band in order to avoid collision with the planet. The new capture methodis demonstrated for a Mercury sample return mission
Comparative analysis of the constitution and implementation of race/skin color field in health information systems: Brazil and South Africa
The inclusion of race/skin color in Health Information Systems makes it possible to measure health inequities. Brazil and South Africa correspond to countries marked by profound inequalities, multiracial constituted that suffered from the historical process of colonization, and had racism legitimized as a structuring model of state development. The objective is to compare the information systems of Brazil and South Africa regarding the configuration and implementation of the item race/skin color. This is a qualitative, descriptive study, based on the content analysis proposed by Bardin. A survey on race/skin color was carried out in health department documents and ministerial sites in both countries. The collected material was processed and analyzed utilizing the IRAMUTEQ R software, version 0.7 alpha 2, with a test Ă 2 > 3.80 (p < 0.05), and by the TABNET application version 4.14 and Excel software, version 2016. In Brazil and Africa South, several health information systems did not include race/skin color. In both countries, health information systems were boosted in the mid-1990s. In Brazil, of the systems that provide data by race/skin color, the inclusion occurred after claims by the black movement. In South Africa, through the creation of the respective systems. The historical configuration of the question of race/skin color in both countries was guided by political and ideological references. In multiracial and unequal countries, race/skin color is a central political category to promote health equity
Second harmonic generation and birefringence of some ternary pnictide semiconductors
A first-principles study of the birefringence and the frequency dependent
second harmonic generation (SHG) coefficients of the ternary pnictide
semiconductors with formula ABC (A = Zn, Cd; B = Si, Ge; C = As, P) with
the chalcopyrite structures was carried out. We show that a simple empirical
observation that a smaller value of the gap is correlated with larger value of
SHG is qualitatively true. However, simple inverse power scaling laws between
gaps and SHG were not found. Instead, the real value of the nonlinear response
is a result of a very delicate balance between different intraband and
interband terms.Comment: 13 pages, 12 figure
Magnetic Field Stimulated Transitions of Excited States in Fast Muonic Helium Ions
It is shown that one can stimulate, by using the present-day laboratory
magnetic fields, transitions between the sub-levels of fast
ions formating in muon catalyzed fusion. Strong fields also cause the
self-ionization from highly excited states of such muonic ions. Both effects
are the consequence of the interaction of the bound muon with the oscillating
field of the Stark term coupling the center-of-mass and muon motions of the
ion due to the non-separability of the collective and internal
variables in this system. The performed calculations show a possibility to
drive the population of the sub-levels by applying a field of a few
, which affects the reactivation rate and is especially important to the
-ray production in muon catalyzed fusion. It is also shown that
the splitting in due to the vacuum polarization slightly
decreases the stimulated transition rates.Comment: 5 figure
Inflation in Realistic D-Brane Models
We find successful models of D-brane/anti-brane inflation within a string
context. We work within the GKP-KKLT class of type IIB string vacua for which
many moduli are stabilized through fluxes, as recently modified to include
`realistic' orbifold sectors containing standard-model type particles. We allow
all moduli to roll when searching for inflationary solutions and find that
inflation is not generic inasmuch as special choices must be made for the
parameters describing the vacuum. But given these choices inflation can occur
for a reasonably wide range of initial conditions for the brane and antibrane.
We find that D-terms associated with the orbifold blowing-up modes play an
important role in the inflationary dynamics. Since the models contain a
standard-model-like sector after inflation, they open up the possibility of
addressing reheating issues. We calculate predictions for the CMB temperature
fluctuations and find that these can be consistent with observations, but are
generically not deep within the scale-invariant regime and so can allow
appreciable values for as well as predicting a potentially
observable gravity-wave signal. It is also possible to generate some admixture
of isocurvature fluctuations.Comment: 39 pages, 21 figures; added references; identified parameters
combining successful inflation with strong warping, as needed for consistency
of the approximation
High-spin structure, K isomers, and state mixing in the neutron-rich isotopes 173Tm and 175Tm
High-spin states in the odd-proton thulium isotopes 173Tm and 175Tm have been studied using deep-inelastic reactions and Îł-ray spectroscopy. In 173Tm, the low-lying structure has been confirmed and numerous new states have been identified, including a three-quasiparticle KÏ= 19/2- isomer with a lifetime of Ï=360(100)ns at 1906keV and a five-quasiparticle KÏ=35/2- isomer with a lifetime of Ï= 175(40)ns at 4048keV. The KÏ=35/2- state is interpreted as a t-band configuration that shows anomalously fast decays. In 175Tm, the low-lying structure has been reevaluated, a candidate state for the 9/2-[514] orbital has been identified at 1175keV, and the 7/2-[523] bandhead has been measured to have a lifetime of Ï= 460(50)ns. Newly identified high-K structures in 175Tm include a KÏ=15/2- isomer with a lifetime of Ï= 64(3)ns at 947keV and a KÏ= 23/2+ isomer with a lifetime of Ï= 30(20) ÎŒs at 1518keV. The KÏ=15/2- isomer shows relatively enhanced decays to the 7/2-[523] band that can be explained by chance mixing with the 15/2- member of the 7/2- band. Multiquasiparticle calculations have been performed for 173Tm and 175Tm, the results of which compare well with the experimentally observed high-spin states
Multiquasiparticle states in the neutron-rich nucleus 174Tm
Deep inelastic and transfer reactions with an 820-MeV, 136Xe beam and various ytterbium and lutetium targets have been employed to study high-spin structures in the neutron-rich thulium isotopes beyond 171Tm. Results in the doubly odd nucleus, 174Tm, include the identification of numerous new two- and four-quasiparticle intrinsic states including several isomers below 1 MeV, and the observation of the KÏ=4- ground state rotational band populated via direct decay from a Ï=153(10)-ÎŒs, KÏ=14- isomer at 2092 keV. The 398-keV, M1 transition linking the isomer and ground state band is abnormally fast for a highly forbidden, ÎK=10 decay. This relative enhancement is explained in terms of mixing of the 13- level with the nearby 13- member of a KÏ=8- rotational band, with an interaction strength of V â 1.4 keV. Multiquasiparticle calculations are compared with the observed states
Two-quasiparticle K-isomers and pairing strengths in the neutron-rich isotopes 174Er and 172Er
Isomeric two-quasiparticle states have been identified in the neutron-rich isotopes 172Er and 174Er using multi-nucleon transfer reactions with 136Xe beams incident on various targets, and Îł-ray spectroscopy with Gammasphere. A candidate for the KÏ=6+ two-quasineutron state in 172Er is found at 1500 keV. In 174Er, a nuclide whose level scheme was previously unknown, a long-lived isomer is identified at 1112 keV decaying via an inhibited E1 transition and revealing the yrast sequence of 174Er. This isomer is proposed to be a KÏ=8- two-quasineutron state, defining a sequence in the N=106 isotones extending from the well-deformed neutron-rich isotope 174Er to the neutron-deficient isotope 188Pb, where the presence of the isomer signifies a prolate minimum in an otherwise spherical well. Configuration-constrained potential-energy surface calculations are used to predict the excitation energies of the 6+ and 8- intrinsic states and as a basis for extracting the pairing force strength, Gn, in the N=104 and N=106 isotones
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