12,045 research outputs found
Renormalized broken-symmetry Schwinger-Dyson equations and the 2PI-1/N expansion for the O(N) model
We derive the renormalized Schwinger-Dyson equations for the one- and
two-point functions in the auxiliary field formulation of
field theory to order 1/N in the 2PI-1/N expansion. We show that the
renormalization of the broken-symmetry theory depends only on the counter terms
of the symmetric theory with . We find that the 2PI-1/N expansion
violates the Goldstone theorem at order 1/N. In using the O(4) model as a low
energy effective field theory of pions to study the time evolution of
disoriented chiral condensates one has to {\em{explicitly}} break the O(4)
symmetry to give the physical pions a nonzero mass. In this effective theory
the {\em additional} small contribution to the pion mass due to the violation
of the Goldstone theorem in the 2-PI-1/N equations should be numerically
unimportant
An update of the JPL program to develop Li-SOCl2 cells
The goal of producing spiral wound D cell was met. The cell design and electrodes, particularly the carbon cathodes were produced in-house. Also all parts were assembled, the welding performed, the electrolyte aided and the cells sealed in-house. The lithium capacity (theoretical) was 19.3 Ah and that of the SOCl2 in the 1.8 m LiAlCl4 electrolyte, 16.4 Ah (a greater excess of SOCl2 is necessary for safe high rate operation). The electrode surface area was 452 sq cm. The carbon electrode comprised Shawinigen Black/Teflon -30 (90/10 by weight) mixture 0.020 inches thick on an expanded metal screen prepared in the JPL laboratory. There were two tab connections to the cathode. The 0.0078 inch thick lithium foil was rolled into an expanded nickel screen. The separator was Mead 934-5 fiberglass material
Quantification of Bronchial Circulation Perfusion in Rats
The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection resulted in Tc99m accumulation in capillaries of the systemic circulation including the bronchial circulation, whereas the IV resulted in Tc99m accumulation in the pulmonary capillaries. Ordered subset expectation maximization (OSEM) was used to reconstruct the SPECT image volumes and a Feldkamp algorithm was used to reconstruct the micro-CT image volumes. The micro-CT and SPECT volumes were registered, the SPECT image volume was segmented using the right and left lung boundaries defined from the micro-CT volume, and the ratio of IA radioactivity accumulation in the left lung to IV radioactivity accumulation in both lungs was used as a measure of left lung flow via the bronchial circulation. This ratio was ~0.02 for the untreated rats compared to the treated animals that had an increased flow ratio of ~0.21 40 days after left pulmonary artery occlusion. This increase in flow to the occluded left lung via the bronchial circulation suggests this will be a useful model for further investigating antiangiogenic treatments
Quantification of Bronchial Circulation Perfusion in Rats
The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection resulted in Tc99m accumulation in capillaries of the systemic circulation including the bronchial circulation, whereas the IV resulted in Tc99m accumulation in the pulmonary capillaries. Ordered subset expectation maximization (OSEM) was used to reconstruct the SPECT image volumes and a Feldkamp algorithm was used to reconstruct the micro-CT image volumes. The micro-CT and SPECT volumes were registered, the SPECT image volume was segmented using the right and left lung boundaries defined from the micro-CT volume, and the ratio of IA radioactivity accumulation in the left lung to IV radioactivity accumulation in both lungs was used as a measure of left lung flow via the bronchial circulation. This ratio was ~0.02 for the untreated rats compared to the treated animals that had an increased flow ratio of ~0.21 40 days after left pulmonary artery occlusion. This increase in flow to the occluded left lung via the bronchial circulation suggests this will be a useful model for further investigating antiangiogenic treatments
Human immunodeficiency virus type 1 coat protein neurotoxicity mediated by nitric oxide in primary cortical cultures.
Science Learning+ Youth Equity Pathways in Informal Science Learning: Survey findings
This document presents an overview of the quantitative survey data findings from the SL+ Equity Pathways in Informal Science Learning project. Further qualitative analysis on some of the open response data is yet to be completed. Findings are grouped into four areas: about the individuals taking part in the survey; their definitions and understanding of equity and related terms; their current equity practice; and their practices around equity work including reading, talking with colleagues and evaluation
Higgs boson production with one bottom quark jet at hadron colliders
We present total rates and kinematic distributions for the associated
production of a single bottom quark and a Higgs boson at the Tevatron and the
LHC. We include next-to-leading order QCD corrections and compare the results
obtained in the four and five flavor number schemes for parton distribution
functions.Comment: 4 pages, 8 figures, RevTeX
Next-to-Next-to-Leading Order Higgs Production at Hadron Colliders
The Higgs boson production cross section at pp and p\bar{p} colliders is
calculated in QCD at next-to-next-to-leading order (NNLO). We find that the
perturbative expansion of the production cross section is well behaved and that
scale dependence is reduced relative to the NLO result. These findings give us
confidence in the reliability of the prediction. We also report an error in the
NNLO correction to Drell-Yan production.Comment: 5 pages, 4 figures, minor change
- …