472 research outputs found
Enzymatic and Electron Transfer Activities in Crystalline Protein Complexes
Enzymatic and electron transfer activities have been studied by polarized absorption spectroscopy in single crystals of both binary and ternary complexes of methylamine dehydrogenase (MADH) with its redox partners. Within the crystals, MADH oxidizes methylamine, and the electrons are passed from the reduced tryptophan tryptophylquinone (TTQ) cofactor to the copper of amicyanin and to the heme of cytochrome c551i via amicyanin. The equilibrium distribution of electrons among the cofactors, and the rate of heme reduction after reaction with substrate, are both dependent on pH. The presence of copper in the ternary complex is not absolutely required for electron transfer from TTQ to heme, but its presence greatly enhances the rate of electron flow to the heme
Flavinylation in wild-type trimethylamine dehydrogenase and differentially charged mutant enzymes: a study of the protein environment around the N1 of the flavin isoalloxazine
Effects of stencil width on surface ocean geostrophic velocity and vorticity estimation from gridded satellite altimeter data
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90421/1/2011JC007367.pd
Effect of Neutrino Heating on Primordial Nucleosynthesis
We have modified the standard code for primordial nucleosynthesis to include
the effect of the slight heating of neutrinos by annihilations. There
is a small, systematic change in the He yield, , which is insensitive to the value of the baryon-to-photon ratio
for 10^{-10}\la \eta \la 10^{-9}. We also find that the
baryon-to-photon ratio decreases by about 0.5\% less than the canonical factor
of 4/11 because some of the entropy in pairs is transferred to
neutrinos. These results are in accord with recent analytical estimates.Comment: 14 pages/4 Figs (upon request
Active Galaxies in the UV
In this article we present different aspects of AGN studies demonstrating the
importance of the UV spectral range. Most important diagnostic lines for
studying the general physical conditions as well as the metalicities in the
central broad line region in AGN are emitted in the UV. The UV/FUV continuum in
AGN excites not only the emission lines in the immediate surrounding but it is
responsible for the ionization of the intergalactic medium in the early stages
of the universe. Variability studies of the emission line profiles of AGN in
the UV give us information on the structure and kinematics of the immediate
surrounding of the central supermassive black hole as well as on its mass
itself.Comment: 29 pages, 13 figures, Ap&SS in pres
The perseverative worry bout: a review of cognitive, affective and motivational factors that contribute to worry perseveration
This paper reviews the cognitive, affective and attentional factors that contribute to individual perseverative worry bouts. We describe how automatic biases in attentional and interpretational processes contribute to threat detection and to the inclusion of negative intrusive thoughts into the worry stream typical of the “what if …?” thinking style of pathological worriers. The review also describes processes occurring downstream from these perceptual biases that also facilitate perseveration, including cognitive biases in beliefs about the nature of the worry process, the automatic deployment of strict goal-directed responses for dealing with the threat, the role of negative mood in facilitating effortful forms of information processing (i.e. systematic information processing styles), and in providing negative information for evaluating the success of the worry bout. We also consider the clinical implications of this model for an integrated intervention programme for pathological worrying
Research to action to address inequities: the experience of the Cape Town Equity Gauge
© 2008 Scott et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Recognizing Intimate Partner Violence in Primary Care: Western Cape, South Africa
Introduction: Interpersonal violence in South Africa is the second highest contributor to the burden of disease after HIV/ AIDS and 62 % is estimated to be from intimate partner violence (IPV). This study aimed to evaluate how women experiencing IPV present in primary care, how often IPV is recognized by health care practitioners and what other diagnoses are made. Methods: At two urban and three rural community health centres, health practitioners were trained to screen all women fo
Pion-nucleus elastic scattering on 12C, 40Ca, 90Zr, and 208Pb at 400 and 500 MeV
Pion-nucleus elastic scattering at energies above the Delta(1232) resonance
is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The
present data provide an opportunity to study the interaction of pions with
nuclei at energies where second-order corrections to impulse approximation
calculations should be small. The results are compared with other data sets at
similar energies, and with four different first-order impulse approximation
calculations. Significant disagreement exists between the calculations and the
data from this experiment
The Nab Experiment: A Precision Measurement of Unpolarized Neutron Beta Decay
Neutron beta decay is one of the most fundamental processes in nuclear
physics and provides sensitive means to uncover the details of the weak
interaction. Neutron beta decay can evaluate the ratio of axial-vector to
vector coupling constants in the standard model, , through
multiple decay correlations. The Nab experiment will carry out measurements of
the electron-neutrino correlation parameter with a precision of and the Fierz interference term to
in unpolarized free neutron beta decay. These results, along with a more
precise measurement of the neutron lifetime, aim to deliver an independent
determination of the ratio with a precision of that will allow an evaluation of and sensitively
test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long
asymmetric spectrometer that guides the decay electron and proton to two large
area silicon detectors in order to precisely determine the electron energy and
an estimation of the proton momentum from the proton time of flight. The Nab
spectrometer is being commissioned at the Fundamental Neutron Physics Beamline
at the Spallation Neutron Source at Oak Ridge National Lab. We present an
overview of the Nab experiment and recent updates on the spectrometer,
analysis, and systematic effects.Comment: Presented at PPNS201
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