146 research outputs found
Photoacoustic effect for multiply scattered light
We consider the photoacoustic effect for multiply scattered light in a random medium. Within the accuracy of the diffusion approximation to the radiative transport equation, we present a general analysis of the sensitivity of a photoacoustic wave to the presence of one or more small absorbing objects. Applications to tumor detection by photoacoustic imaging are suggested
Release Note -- Vbfnlo-2.6.0
Vbfnlo is a flexible parton level Monte Carlo program for the simulation of
vector boson fusion (VBF), double and triple vector boson (plus jet) production
in hadronic collisions at next-to-leading order (NLO) in the strong coupling
constant, as well as Higgs boson plus two jet production via gluon fusion at
the one-loop level. This note briefly describes the main additional features
and processes that have been added in the new release -- Vbfnlo Version 2.6.0.
At NLO QCD diboson production (W\gamma, WZ, ZZ, Z\gamma and \gamma\gamma),
same-sign W pair production via vector boson fusion and the process
W\gamma\gamma j have been implemented (for which one-loop tensor integrals up
to six-point functions are included). In addition, gluon induced diboson
production can be studied separately at the leading order (one-loop) level. The
diboson processes WW, WZ and W\gamma can be run with anomalous gauge boson
couplings, and anomalous couplings between a Higgs and a pair of gauge bosons
is included in WW, ZZ, Z\gamma and \gamma\gamma diboson production. The code
has also been extended to include anomalous gauge boson couplings for single
vector boson production via VBF, and a spin-2 model has been implemented for
diboson pair production via vector boson fusion.Comment: 14 pages, 6 tables; new code available at
http://www-itp.particle.uni-karlsruhe.de/vbfnlo
National trends in emergency room diagnosis of pulmonary embolism, 2001–2010: a cross-sectional study
Background:
Little is known about the United States diagnosis and burden of pulmonary embolism (PE) in the emergency department (ED), and their evolution over the past decade. We examined nationally representative data to evaluate factors associated with and trends in ED diagnosis of PE.
Methods:
We conducted a cross-sectional study using National Hospital Ambulatory Medical Care Survey (NHAMCS) data from January 1, 2001 to December 31, 2010. We identified all ED patient visits where PE was diagnosed and corresponding demographic, hemodynamic, testing and disposition data. Analyses were performed using descriptive statistics and multivariable logistic regression.
Results:
During the study period 988,000 weighted patient visits with diagnosis of PE were identified. Among patients with an ED visit, the likelihood of having a diagnosis of PE per year increased significantly from 2001 to 2010 (odds ratio [OR] 1.091, 95% confidence interval [CI] 1.034-1.152, P = 0.002 for trend) when adjusted for demographic and hospital information. In contrast, when further adjusted for the use of computed tomography (CT) among patients in the ED, the likelihood of having a diagnosis of PE per year did not change (OR 1.041, 95% CI 0.987-1.097, P = 0.14). Overall, 75.1% of patients seen with a diagnosis of PE were hemodynamically stable; 86% were admitted with an in-hospital death rate under 3%.
Conclusions:
The proportion of ED visits with a diagnosis of PE increased significantly from 2001 to 2010 and this rise can be attributed in large part to the increased availability and use of CT. Most of these patients were admitted with low in-hospital mortality.
Keywords:
Pulmonary embolism Emergency department Computed Tomography (CT) pulmonary angiograph
Simulating High-Dimensional Multivariate Data using the bigsimr R Package
It is critical to accurately simulate data when employing Monte Carlo
techniques and evaluating statistical methodology. Measurements are often
correlated and high dimensional in this era of big data, such as data obtained
in high-throughput biomedical experiments. Due to the computational complexity
and a lack of user-friendly software available to simulate these massive
multivariate constructions, researchers resort to simulation designs that posit
independence or perform arbitrary data transformations. To close this gap, we
developed the Bigsimr Julia package with R and Python interfaces. This paper
focuses on the R interface. These packages empower high-dimensional random
vector simulation with arbitrary marginal distributions and dependency via a
Pearson, Spearman, or Kendall correlation matrix. bigsimr contains
high-performance features, including multi-core and
graphical-processing-unit-accelerated algorithms to estimate correlation and
compute the nearest correlation matrix. Monte Carlo studies quantify the
accuracy and scalability of our approach, up to . We describe example
workflows and apply to a high-dimensional data set -- RNA-sequencing data
obtained from breast cancer tumor samples.Comment: 22 pages, 10 figures,
https://cran.r-project.org/web/packages/bigsimr/index.htm
Entwicklungsmethodiken zur Integration von Anwendungssystemen in überbetrieblichen Geschäftsprozessen - ein Überblick über ausgewählte Ansätze
Die überbetriebliche Integration von Anwendungssystemen ist ein wichtiger Erfolgsfaktor für eine durchgehende Automatisierung überbetrieblicher Geschäftsprozesse. Eine solche Integration erfordert eine Kopplung der beteiligten Anwendungssysteme durch Kopplungssysteme. Aufgrund der in der Regel hohen Komplexität der Kopplungen werden umfassende Ansätze benötigt, die v. a. die Aspekte Modellierung und Vorgehen im Rahmen einer Entwicklungsmethodik berücksichtigen. Der vorliegende Beitrag stellt zunächst eine Systematik zur Erfassung wesentlicher Aspekte solcher Ansätze vor. Anschließend werden vier ausgewählte Ansätze unter Verwendung dieser Systematik beschrieben
Do acute elevations of serum creatinine in primary care engender an increased mortality risk?
Background: The significant impact Acute Kidney Injury (AKI) has on patient morbidity and mortality emphasizes the need for early recognition and effective treatment. AKI presenting to or occurring during hospitalisation has been widely studied but little is known about the incidence and outcomes of patients experiencing acute elevations in serum creatinine in the primary care setting where people are not subsequently admitted to hospital. The aim of this study was to define this incidence and explore its impact on mortality. Methods: The study cohort was identified by using hospital data bases over a six month period. Inclusion criteria: People with a serum creatinine request during the study period, 18 or over and not on renal replacement therapy. The patients were stratified by a rise in serum creatinine corresponding to the Acute Kidney Injury Network (AKIN) criteria for comparison purposes. Descriptive and survival data were then analysed. Ethical approval was granted from National Research Ethics Service (NRES) Committee South East Coast and from the National Information Governance Board. Results: The total study population was 61,432. 57,300 subjects with ‘no AKI’, mean age 64.The number (mean age) of acute serum creatinine rises overall were, ‘AKI 1’ 3,798 (72), ‘AKI 2’ 232 (73), and ‘AKI 3’ 102 (68) which equates to an overall incidence of 14,192 pmp/year (adult). Unadjusted 30 day survival was 99.9% in subjects with ‘no AKI’, compared to 98.6%, 90.1% and 82.3% in those with ‘AKI 1’, ‘AKI 2’ and ‘AKI 3’ respectively. After multivariable analysis adjusting for age, gender, baseline kidney function and co-morbidity the odds ratio of 30 day mortality was 5.3 (95% CI 3.6, 7.7), 36.8 (95% CI 21.6, 62.7) and 123 (95% CI 64.8, 235) respectively, compared to those without acute serum creatinine rises as defined. Conclusions: People who develop acute elevations of serum creatinine in primary care without being admitted to hospital have significantly worse outcomes than those with stable kidney function
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