296 research outputs found
Astrophysical Reaction Rates for B(p,)Be and B(p,)Be From a Direct Model
The reactions B(p,)Be and B(p,)Be
are studied at thermonuclear energies using DWBA calculations. For both
reactions, transitions to the ground states and first excited states are
investigated. In the case of B(p,)Be, a resonance at
keV can be consistently described in the potential model, thereby
allowing the extension of the astrophysical -factor data to very low
energies. Strong interference with a resonance at about keV
require a Breit-Wigner description of that resonance and the introduction of an
interference term for the reaction B(p,)Be. Two
isospin resonances (at keV and keV)
observed in the B+p reactions necessitate Breit-Wigner resonance and
interference terms to fit the data of the B(p,)Be
reaction. -factors and thermonuclear reaction rates are given for each
reaction. The present calculation is the first consistent parametrization for
the transition to the ground states and first excited states at low energies.Comment: 27 pages, 5 Postscript figures, uses RevTex and aps.sty; preprint
also available at http://quasar.physik.unibas.ch/ Phys. Rev. C, in pres
Hausdorff dimension of operator semistable L\'evy processes
Let be an operator semistable L\'evy process in \rd
with exponent , where is an invertible linear operator on \rd and
is semi-selfsimilar with respect to . By refining arguments given in
Meerschaert and Xiao \cite{MX} for the special case of an operator stable
(selfsimilar) L\'evy process, for an arbitrary Borel set B\subseteq\rr_+ we
determine the Hausdorff dimension of the partial range in terms of the
real parts of the eigenvalues of and the Hausdorff dimension of .Comment: 23 page
Observation of 46Cr and testing and isobaric multiplet mass equation at high spin
An experimental study was carried out to observe excited states in 46Cr using the 12C(36Ar,2n) reaction with GAMMASPHERE and the FMA. The yrast band in 46Cr and the T=1 states in 46V were established up to (tentatively) 12+, the highest spin T=1 triplet unknown. The results were used to test f p-shell model calculations
PREDICTING THE SUMMER TEMPERATURE OF SMALL STREAMS IN SOUTHWESTERN WISCONSIN 1
One of the biggest challenges in managing cold water streams in the Midwest is understanding how stream temperature is controlled by the complex interactions among meteorologic processes, channel geometry, and ground water inflow. Inflow of cold ground water, shade provided by riparian vegetation, and channel width are the most important factors controlling summer stream temperatures. A simple screening model was used to quantitatively evaluate the importance of these factors and guide management decisions. The model uses an analytical solution to the heat transport equation to predict steady-state temperature throughout a stream reach. The model matches field data from four streams in southwestern Wisconsin quite well (typically within 1°C) and helps explain the observed warming and cooling trends along each stream reach. The distribution of ground water inflow throughout a stream reach has an important influence on stream temperature, and springs are especially effective at providing thermal refuge for fish. Although simple, this model provides insight into the importance of ground water and the impact different management strategies, such as planting trees to increase shade, may have on summer stream temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74032/1/j.1752-1688.2005.tb03714.x.pd
Risk factors for fluoroquinolone-resistant Escherichia coli in adults with community-onset febrile urinary tract infection
Objectives To assess risk factors for fluoroquinolone resistance in community-onset febrile Escherichia coli urinary tract infection (UTI). Methods A nested case-control study within a cohort of consecutive adults with febrile UTI presenting at primary healthcare centres or emergency departments during January 2004 through December 2009. Resistance was defined using EUCAST criteria (ciprofloxacin MIC >1.0 mg/L). Cases were subjects with fluoroquinolone-resistant E. coli, and controls those with fluoroquinolone-susceptible isolates. Multivariable logistic regression analysis was used to identify potential risk factors for fluoroquinolone resistance. Results Of 787 consecutive patients, 420 had E. coli-positive urine cultures. Of these, 51 (12%) were fluoroquinolone resistant. Independent risk factors for fluoroquinolone resistance were urinary catheter [odds ratio (OR) 3.1; 95% confidence interval (CI) 0.9-11.6], recent hospitalization (OR 2.0; 95% CI 1.0-4.3) and fluoroquinolone use in the past 6 months (OR 17.5; 95% CI 6.0-50.7). Environmental factors (e.g. contact with animals or hospitalized household members) were not associated with fluoroquinolone resistance. Of fluoroquinolone-resistant strains, 33% were resistant to amoxicillin/clavulanate and 65% to trimethoprim/sulfamethoxazole; 14% were extended-spectrum β-lactamase (ESBL) positive compared with <1% of fluoroquinolone-susceptible isolates. Conclusions Recent hospitalization, urinary catheter and fluoroquinolone use in the past 6 months were independent risk factors for fluoroquinolone resistance in community-onset febrile E. coli UTI. Contact with animals or hospitalized household members was not associated with fluoroquinolone resistance. Fluoroquinolone resistance may be a marker of broader resistance, including ESBL positivity.Immunogenetics and cellular immunology of bacterial infectious disease
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Affect, Relationality and the 'Problem of Personality'
This peer-reviewed journal article sets out an argument regarding the importance of genealogical work for understanding concepts such as affect and suggestion
Implications of H.E.S.S. observations of pulsar wind nebulae
In this review paper on pulsar wind nebulae (PWN) we discuss the properties
of such nebulae within the context of containment against cross-field diffusion
(versus normal advection), the effect of reverse shocks on the evolution of
offset ``Vela-like'' PWN, constraints on maximum particle energetics, magnetic
field strength estimates based on spectral and spatial properties, and the
implication of such field estimates on the composition of the wind. A
significant part of the discussion is based on the High Energy Stereoscopic
System ({\it H.E.S.S.} or {\it HESS}) detection of the two evolved pulsar wind
nebulae Vela X (cocoon) and HESS J1825-137. In the case of Vela X (cocoon) we
also review evidence of a hadronic versus a leptonic interpretation, showing
that a leptonic interpretation is favored for the {\it HESS} signal. The
constraints discussed in this review paper sets a general framework for the
interpretation of a number of offset, filled-center nebulae seen by {\it HESS}.
These sources are found along the galactic plane with galactic latitudes
, where significant amounts of molecular gas is found. In these
regions, we find that the interstellar medium is inhomogeneous, which has an
effect on the morphology of supernova shock expansion. One consequence of this
effect is the formation of offset pulsar wind nebulae as observed.Comment: to appear in Springer Lecture Notes on Neutron Stars and Pulsars: 40
years after their discovery, eds. W. Becke
New Strong-Field QED Effects at ELI: Nonperturbative Vacuum Pair Production
Since the work of Sauter, and Heisenberg, Euler and K\"ockel, it has been
understood that vacuum polarization effects in quantum electrodynamics (QED)
predict remarkable new phenomena such as light-light scattering and pair
production from vacuum. However, these fundamental effects are difficult to
probe experimentally because they are very weak, and they are difficult to
analyze theoretically because they are highly nonlinear and/or nonperturbative.
The Extreme Light Infrastructure (ELI) project offers the possibility of a new
window into this largely unexplored world. I review these ideas, along with
some new results, explaining why quantum field theorists are so interested in
this rapidly developing field of laser science. I concentrate on the
theoretical tools that have been developed to analyze nonperturbative vacuum
pair production.Comment: 20 pages, 9 figures; Key Lecture at the ELI Workshop and School on
"Fundamental Physics with Ultra-High Fields", 29 Sept - 2 Oct. 2008,
Frauenworth Monastery, Germany; v2: refs updated, English translations of
reviews of Nikishov and Ritu
Test beam performance measurements for the Phase I upgrade of the CMS pixel detector
A new pixel detector for the CMS experiment was built in order to cope with the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking with a reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and allows operation at low comparator thresholds. In this paper, comprehensive test beam studies are presented, which have been conducted to verify the design and to quantify the performance of the new detector assemblies in terms of tracking efficiency and spatial resolution. Under optimal conditions, the tracking efficiency is (99.95 ± 0.05) %, while the intrinsic spatial resolutions are (4.80 ± 0.25) μm and (7.99 ± 0.21) μm along the 100 μm and 150 μm pixel pitch, respectively. The findings are compared to a detailed Monte Carlo simulation of the pixel detector and good agreement is found.Peer reviewe
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