12,139 research outputs found
Decay
Motivated by the experimental measurement of the decay rate, , and
the longitudinal polarization, , in the Cabibbo favored decay , we have studied theoretical prediction within the context of
factorization approximation invoking several form factors models. We were able
to obtain agreement with experiment for both and by using
experimentally measured values of the form factors ,
and in the semi-leptonic decay . We have also included in our calculation the effect of the
final state interaction () by working with the partial waves amplitudes
, and . Numerical calculation shows that the decay amplitude is
dominated by wave, and that the polarization is sensitive to the
interference between and waves. The range of the phase difference
accommodated by experimental error in
is large.Comment: 7 pages, LaTe
Closed-circuit television welding- electrode guidance system
Closed-circuit TV camera is mounted parallel to electrode and moves along with it. Camera is scanned along seam so seam is viewed parallel with scan lines on TV monitor. Two fiber optics illuminators are attached to guidance system; they illuminate seam for TV camera
Virtual Data in CMS Analysis
The use of virtual data for enhancing the collaboration between large groups
of scientists is explored in several ways:
- by defining ``virtual'' parameter spaces which can be searched and shared
in an organized way by a collaboration of scientists in the course of their
analysis;
- by providing a mechanism to log the provenance of results and the ability
to trace them back to the various stages in the analysis of real or simulated
data;
- by creating ``check points'' in the course of an analysis to permit
collaborators to explore their own analysis branches by refining selections,
improving the signal to background ratio, varying the estimation of parameters,
etc.;
- by facilitating the audit of an analysis and the reproduction of its
results by a different group, or in a peer review context.
We describe a prototype for the analysis of data from the CMS experiment
based on the virtual data system Chimera and the object-oriented data analysis
framework ROOT. The Chimera system is used to chain together several steps in
the analysis process including the Monte Carlo generation of data, the
simulation of detector response, the reconstruction of physics objects and
their subsequent analysis, histogramming and visualization using the ROOT
framework.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, LaTeX, 7 eps figures. PSN
TUAT010. V2 - references adde
Global Measurements of Optically Thin Ice Clouds Using CALIOP
Optically thin ice clouds have been shown to have a net warming effect on the globe but, because passive instruments are not sensitive to optically thin clouds, the occurrence frequency of this class of clouds is greatly underestimated in historical passive sensor cloud climatology. One major strength of CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), onboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) spacecraft, is its ability to detect these thin clouds, thus filling an important missing piece in the historical data record. This poster examines the full mission of CALIPSO Level 2 data, focusing on those CALIOP retrievals identified as thin ice clouds according to the definition shown to the right. Using this definition, thin ice clouds are identified and counted globally and vertically for each season. By examining the spatial and seasonal distributions of these thin clouds we hope to gain a better understanding these thin ice clouds and how their global distribution has changed over the mission. This poster showcases when and where CALIOP detects thin ice clouds and examines a case study of the eastern pacific and the effects seen from the El Nino-Southern Oscillation (ENSO)
Fertility in New York State in the Civil War Era
This paper analyzes a five percent systematic sample of households from the manuscripts of the New York State Census of 1865, the first in the United States to ask a question on children ever born. The sample of seven counties (Allegany, Dutchess, Montgomery, Rensselaer, Steuben, Tompkins, and Warren) was selected to provide a diversity of locations, settlement dates, and types of agricultural economy. The parity data indicate a strong decline in marital fertility during the first part of the 19th Century; little evidence of fertility control within marriage is found for the oldest women in the sample, but analysis of parity progression ratios indicates that control had emerged by the midpoint of the 19th Century. Fertility decline was initially most evident in the urban, more economically developed areas, but eventual levels were equal in the urban and rural parts of the sample. While a marital fertility transition occurred in 19th Century New York, many couples continued to have quite high levels of fertility, indicating the difficulty that many couples probably faced in controlling their reproduction.
External tank gaseous oxygen line simulated lightning tests
Tests were made to evaluate the effects of lightning strikes on the shuttle external tank gaseous oxygen pressurization line. This line, designed to conduct gaseous oxygen may also act as a lightning conductor. Questions have been raised as to the potential hazard of this line as a lightning conductor with speculation as to the damage that might occur to the pressurization line, and the adjacent thermal protective surfaces, from a lightning strike. The region of investigation was from above the cone of the launch tower lightning protection to 15.24 km (50, 000 ft) altitude. Tests were performed on samples of thin wall stainless steel tubing filled with gaseous oxygen under simulated flight conditions. No specimen malfunctions occurred when the tests were conducted according to JSC specifications. Based on the JSC specifications and the results of these tests, it is concluded that a lightning strike will not cause a malfunction of the shuttle external tank gaseous oxygen line made of the representative material tested
Where are all the gravastars? Limits upon the gravastar model from accreting black holes
The gravastar model, which postulates a strongly correlated thin shell of
anisotropic matter surrounding a region of anti-de Sitter space, has been
proposed as an alternative to black holes. We discuss constraints that
present-day observations of well-known black hole candidates place on this
model. We focus upon two black hole candidates known to have extraordinarily
low luminosities: the supermassive black hole in the Galactic Center,
Sagittarius A*, and the stellar-mass black hole, XTE J1118+480. We find that
the length scale for modifications of the type discussed in Chapline et al.
(2003) must be sub-Planckian.Comment: 11 pages, 4 figure
Feature Selection of Post-Graduation Income of College Students in the United States
This study investigated the most important attributes of the 6-year
post-graduation income of college graduates who used financial aid during their
time at college in the United States. The latest data released by the United
States Department of Education was used. Specifically, 1,429 cohorts of
graduates from three years (2001, 2003, and 2005) were included in the data
analysis. Three attribute selection methods, including filter methods, forward
selection, and Genetic Algorithm, were applied to the attribute selection from
30 relevant attributes. Five groups of machine learning algorithms were applied
to the dataset for classification using the best selected attribute subsets.
Based on our findings, we discuss the role of neighborhood professional degree
attainment, parental income, SAT scores, and family college education in
post-graduation incomes and the implications for social stratification.Comment: 14 pages, 6 tables, 3 figure
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