122,134 research outputs found
Remote Sensing of Giant Reed with QuickBird Satellite Imagery
QuickBird high resolution (2.8 m) satellite imagery was
evaluated for distinguishing giant reed (
Arundo donax
L.) infestations
along the Rio Grande in southwest Texas. (PDF has 5 pages.
Oscillating bounce solutions and vacuum tunneling in de Sitter spacetime
We study a class of oscillating bounce solutions to the Euclidean field
equations for gravity coupled to a scalar field theory with two, possibly
degenerate, vacua. In these solutions the scalar field crosses the top of the
potential barrier times. Using analytic and numerical methods, we examine
how the maximum allowed value of depends on the parameters of the theory.
For a wide class of potentials is determined by the value of the
second derivative of the scalar field potential at the top of the barrier.
However, in other cases, such as potentials with relatively flat barriers, the
determining parameter appears instead to be the value of this second derivative
averaged over the width of the barrier. As a byproduct, we gain additional
insight into the conditions under which a Coleman-De Luccia bounce exists. We
discuss the physical interpretation of these solutions and their implications
for vacuum tunneling transitions in de Sitter spacetime.Comment: 31 pages, 11 figure
The Directional Dependence of Apertures, Limits and Sensitivity of the Lunar Cherenkov Technique to a UHE Neutrino Flux
We use computer simulations to obtain the directional-dependence of the lunar
Cherenkov technique for ultra-high energy (UHE) neutrino detection. We
calculate the instantaneous effective area of past lunar Cherenkov experiments
as a function of neutrino arrival direction, and hence the
directional-dependence of the combined limit imposed by GLUE and the experiment
at Parkes.
We also determine the directional dependence of the aperture of future
planned experiments with ATCA, ASKAP and the SKA to a UHE neutrino flux, and
calculate the potential annual exposure to astronomical objects as a function
of angular distance from the lunar trajectory through celestial coordinates.Comment: 17 pages, 7 figures; Submitted to Astroparticle Physic
System identification, time series analysis and forecasting:The Captain Toolbox handbook.
CAPTAIN is a MATLAB compatible toolbox for non stationary time series analysis, system identification, signal processing and forecasting, using unobserved components models, time variable parameter models, state dependent parameter models and multiple input transfer function models. CAPTAIN also includes functions for true digital control
Physical Transport and Chemical Behavior of Dispersed Oil
During response operations, scientific information is provided to decision makers, such as the Federal On-Scene Coordinator (FOSC), state and federal trustees, and the public. The decision to use chemical dispersants during a response is made among all these parties, and during the Deepwater Horizon (DWH) oil spill the dispersant discussion included both surface and subsurface application of chemical dispersants. This paper is intended to provide perspective on research needs considered pre- and post-DWH oil spill related to response modeling and data collection needs for decision support of dispersant application and its potential effects. Given time constraints for implementing models and sampling strategies for response, requirements for data and types of questions to be addressed may be significantly different than requirements for research or damage assessment activities. At the time of this writing, just over a year after the successful response operations to cap the well, many studies are still in progress, and data are still being collected and evaluated to assess dispersant effectiveness and possible impacts. More information and research results will become available over the next months to years. Thus these research needs, as summarized for this workshop, should be evaluated again at a later time
Ethnicity, Obesity, and Type 2 Diabetes of Adults in Urban Populations of Central America
The purpose of this meta-analysis was to examine the impact of ethnicity and obesity as it relates to Type-2 Diabetes (T2D) in specific Central American countries. A meta-analysis was conducted to determine the association of ethnicity, obesity, and T2D. Four studies that qualified for inclusion were identified by searching MEDLINE and PubMed databases. The studies on the association of ethnicity and T2D had a combined population resulted in 265,858 study participants. Two studies on the association of obesity and T2D had 197,899 participants. An analysis of the data was conducted utilizing the relative risk ration, odds ratio, and forest plots. The comparison of the relative risk of T2D across ethnic categories by studies range for Blacks was 1.59 to 2.74, Asians was 1.43 to 2.08, and Hispanics .92 to 2.91. The ethnic difference in the prevalence of diabetes was almost two-fold higher in all ethnic groups than among the Caucasians with a significance level of 95%. A comparison of relative risk of T2D across weight categories was significantly higher among those with a diagnosed of diabetes in all reported areas. The odds ratio was very close to the risk ratio in both ethnicity and obesity to the development of T2D.The meta-analysis findings documented that an association does exist between ethnicity and obesity to the development of type 2 diabetes
Meta-Analysis of the Relationship Between Ethnicity, Obesity, and Type 2 Diabetes of Adults in Urban Populations of Central America
The purpose of this meta-analysis was to examine the impact of ethnicity and obesity as it relates to Type-2 Diabetes (T2D) in specific Central American countries. A meta-analysis was conducted to determine the association of ethnicity, obesity, and T2D. Four studies that qualified for inclusion were identified by searching MEDLINE and PubMed databases. The studies on the association of ethnicity and T2D had a combined population resulted in 265,858 study participants. Two studies on the association of obesity and T2D had 197,899 participants. An analysis of the data was conducted utilizing the relative risk ration, odds ratio, and forest plots. The comparison of the relative risk of T2D across ethnic categories by studies range for Blacks was 1.59 to 2.74, Asians was 1.43 to 2.08, and Hispanics .92 to 2.91. The ethnic difference in the prevalence of diabetes was almost two-fold higher in all ethnic groups than among the Caucasians with a significance level of 95%. A comparison of relative risk of T2D across weight categories was significantly higher among those with a diagnosed of diabetes in all reported areas. The odds ratio was very close to the risk ratio in both ethnicity and obesity to the development of T2D. The meta-analysis findings documented that an association does exist between ethnicity and obesity to the development of type 2 diabetes
Influence of the Dirac sea on proton electromagnetic knockout
We use the relativistic distorted-wave impulse approximation (RDWIA) to study
the effects of negative-energy components of Dirac wave functions on the
left-right asymmetry for (e,e'p) reactions on 16-O with 0.2 < Q^2 < 0.8 and
12-C with 0.6 < Q^2 < 1.8 (GeV/c)^2. Spinor distortion is more important for
the bound state than for the ejectile and the net effect decreases with Q^2.
Spinor distortion breaks Godon equivalence and the data favor the CC2 operator
with intermediate coupling to the sea. The left-right asymmetry for Q^2 < 1.2
(GeV/c)^2 is described well by RDWIA calcuations, but at Q^2 = 1.8 (GeV/c)^2
the observed variation with missing momentum is flatter than predicted.Comment: 12 pages, 9 figures, to be submitted to PR
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