1,601 research outputs found
Confirmation of the detection of B-modes in the Planck polarization maps
One of the main problems for extracting the Cosmic Microwave Background (CMB)
from submm/mm observations is to correct for the Galactic components, mainly
synchrotron, free - free and thermal dust emission with the required accuracy.
Through a series of papers, it has been demonstrated that this task can be
fulfilled by means of simple neural networks with high confidence. The main
purpose of this paper is to demonstrate that the CMB BB power spectrum detected
in the Planck 2015 polarization maps is present in the improved Planck 2017
maps with higher signal-to-noise ratio. Two features have been detected in the
EB power spectrum in the new data set, both with S/N 4 . The origin of
these features is most likely leakage from E to B with a level of about 1 per
cent. This leakage gives no significant contribution to the detected BB power
spectrum. The TB power spectrum is consistent with a zero signal. Altogether,
the BB power spectrum is not consistent with the 'canonical' tensor-to-scalar
models combined with gravitational lensing spectra. These results will give
additional strong arguments for support to the proposed polarization satellite
projects to follow up on the Planck mission .Comment: accepted for puplication in Astronomical Note
Kinetics of exciton photoluminescence in type-II semiconductor superlattices
The exciton decay rate at a rough interface in type-II semiconductor
superlattices is investigated. It is shown that the possibility of
recombination of indirect excitons at a plane interface essentially affects
kinetics of the exciton photoluminescence at a rough interface. This happens
because of strong correlation between the exciton recombination at the plane
interface and at the roughness. Expressions that relate the parameters of the
luminescence kinetics with statistical characteristics of the rough interface
are obtained. The mean height and length of roughnesses in GaAs/AlAs
superlattices are estimated from the experimental data.Comment: 3 PostScript figure
Using Evaluation to Improve and Promote America Reads
This report covers: Project Objectives; Collecting Data; Sample Instruments; Analyzing Data; and Using Evaluation Findings
What works for Nutrition? Stories of success from Vietnam, Uganda and Kenya
This report discusses the drivers of progress in tackling multiple forms of malnutrition in these three countries: Vietnam, Uganda, and Kenya. It also identifies some of the challenges which pose as barriers to sustaining progress. Finally, it makes recommendations for key stakeholders such as governments of high burden countries, donor governments, development partners, and civil society, on their role to promote further success
The Employment, Earnings, and Income of Less-Skilled Workers over the Business Cycle
In this paper, I examine the effect of business cycles on the employment, earnings, and income of persons in different demographic groups. I classify individuals by sex, education, and race. The analysis uses data from the Current Population Surveyâs Outgoing Rotation Group data, covering the period 1979â1992, and March Annual Demographic File data, covering the period 1975â1997. Many different individual and family outcome measures are considered, including employment to population ratios, weekly earnings, hourly earnings, annual hours, annual earnings, family earnings, family transfer income, and total family income. The regression model is specified such that the key parameters measure how the labor market outcomes of less-skilled workers vary with the business cycle relative to the variability for high-skill groups. The analysis uses variation across MSAs in the timing and severity of shocks. The results consistently show that individuals with lower educational levels, nonwhites, and low-skill women experience greater cyclical fluctuation than high-skill men. These results are the most striking when examining comprehensive measures of labor force activity such as the likelihood of full-time, full-year work. Government transfers and the earnings of other family members decrease the differences between groups, resulting in more skill-group-neutral effects of business cycles on family income than on individual earnings. The paper examines the stability of these results by comparing evidence across the 1982 and 1992 recessions. The evidence suggests that the 1992 recession led to more uniform effects across skill groups than did earlier cycles.
T>0 properties of the infinitely repulsive Hubbard model for arbitrary number of holes
Based on representations of the symmetric group , explicit and exact
Schr\"odinger equation is derived for Hubbard model in any
dimensions with arbitrary number of holes, which clearly shows that during the
movement of holes the spin background of electrons plays an important role.
Starting from it, at T=0 we have analyzed the behaviour of the system depending
on the dimensionality and number of holes. Based on the presented formalism
thermodynamic quantities have also been expressed using a loop summation
technique in which the partition function is given in terms of characters of
. In case of the studied finite systems, the loop summation have been
taken into account exactly up to the 14-th order in reciprocal temperature and
the results were corrected in higher order based on Monte Carlo simulations.
The obtained results suggest that the presented formalism increase the
efficiency of the Monte Carlo simulations as well, because the spin part
contribution of the background is automatically taken into account by the
characters of .Comment: 26 pages, 1 embedded ps figure; Phil. Mag. B (in press
DEVELOPING, MODELLING AND MAPPING OF CRITICAL LOADS AND THEIR INPUT DATA STATUS REPORT ON THE CALL FOR EUROPEAN CRITICAL LOADS ON ACIDIFICATION AND EUTROPHICATION
Programme (ICP) on the Modelling and Mapping of Critical Levels and Loads and Air Pollution Effects, Risks and Trends, with the assistance of the secretaria
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