27,477 research outputs found
Atmospheric Aerosol Limb Scanning Based on the Lunar Eclipses Photometry
The work is devoted to the analysis of the surface photometric observations
of two total lunar eclipses in 2004. The lunar surface relative brightness
distribution inside the umbra was used to retrieve the vertical distribution of
aerosol extinction of the solar radiation expanding by a tangent path and its
dependence on the location at the limb of the Earth. The upper altitude of
troposphere aerosol layer was estimated for different latitude zones. The
correlation between additional aerosol extinction in the upper troposphere and
cyclones was investigated.Comment: 17 pages, 10 figures, submitted to Journal of Quantitative
Spectroscopy and Radiative Transfe
Race, Economics, And Social Status
Social and economic status of an individual or group can be measured as a blend of wealth, income, occupation, and education. Other contributors to social and economic status include race, ethnicity, home ownership, family size, family types, and even types of foods purchased. The combination of social and economic status can reveal a group or individual\u27s unequal access to resources, privilege, power, and control in a society. This Spotlight on Statistics examines Consumer Expenditure Survey data to explore the patterns of social and economic factors by race and ethnicit
Income and Spending Patterns Among Black Households
Household spending data can offer great insight on how households choose and prioritize their wants and needs. In addition, changes in the household spending market basket help to determine Social Securityās general benefit increases, based on cost of living, as measured by the Consumer Price Index. Moreover, such information is widely used by policymakers and researchers to study the impact of inflation and government economic policy.
Data from the U.S. Bureau of Labor Statistics (BLS) Consumer Expenditure (CE) Survey provide information on annual household spending. From these aggregated data, analysts, in government, business, labor, and academia, can generalize about consumer behavior in the U.S. population. However, looking at demographic subgroups of the population can give us a deeper understanding of consumption preferences and spending behavior for a particular group. Using data from the CE Survey, this article looks at the household spending and the income distribution of all Black households. It then compares and contrasts the spending patterns of low-income Black households to their high-income counterparts. Findings show that the average amount of pretax income for Black households is about 70 percent of the national average. In addition, the analysis based on income shows that tobacco and smoking supplies were the only expenditure category in which high-income Black households did not outspend low-income Black households
Superfluid hydrodynamics in the inner crust of neutron stars
The inner crust of neutron stars is supposed to be inhomogeneous and composed
of dense structures (clusters) that are immersed in a dilute gas of unbound
neutrons. Here we consider spherical clusters forming a BCC crystal and
cylindrical rods arranged in a hexagonal lattice. We study the relative motion
of these dense structures and the neutron gas using superfluid hydrodynamics.
Within this approach, which relies on the assumption that Cooper pairs are
small compared to the crystalline structures, we find that the entrainment of
neutrons by the clusters is very weak since neutrons of the gas can flow
through the clusters. Consequently, we obtain a low effective mass of the
clusters and a superfluid density that is even higher than the density of
unbound neutrons. Consequences for the constraints from glitch observations are
discussed.Comment: 13 pages, 12 figures, figures and discussions added. Accepted in
Phys. Rev.
Collective Modes in a Superfluid Neutron Gas within the Quasiparticle Random-Phase Approximation
We study collective excitations in a superfluid neutron gas at zero
temperature within the quasiparticle random phase approximation. The
particle-hole residual interaction is obtained from a Skyrme functional, while
a separable interaction is used in the pairing channel which gives a realistic
density dependence of the pairing gap. In accordance with the Goldstone
theorem, we find an ungapped collective mode (analogous to the
Bogoliubov-Anderson mode). At low momentum, its dispersion relation is
approximately linear and its slope coincides with the hydrodynamic speed of
sound calculated with the Skyrme equation of state. The response functions are
compared with those obtained within the Landau approximation. We also compute
the contribution of the collective mode to the specific heat of the neutron
gas, which is relevant for the thermodynamic properties of the inner crust of
neutron stars.Comment: 12 page
Liquid-gas coexistence vs. energy minimization with respect to the density profile in the inhomogeneous inner crust of neutron stars
We compare two approaches to describe the inner crust of neutron stars: on
the one hand, the simple coexistence of a liquid (clusters) and a gas phase,
and on the other hand, the energy minimization with respect to the density
profile, including Coulomb and surface effects. We find that the
phase-coexistence model gives a reasonable description of the densities in the
clusters and in the gas, but the precision is not high enough to obtain the
correct proton fraction at low baryon densities. We also discuss the surface
tension and neutron skin obtained within the energy minimization.Comment: 7 pages, 8 figures, to be published in Phys. Rev.
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