4,945 research outputs found
Assessment of pulmonary edema: principles and practice
Pulmonary edema increasingly is recognized as a perioperative complication affecting outcome. Several risk factors have been identified, including those of cardiogenic origin, such as heart failure or excessive fluid administration, and those related to increased pulmonary capillary permeability secondary to inflammatory mediators.
Effective treatment requires prompt diagnosis and early intervention. Consequently, over the past 2 centuries a concentrated effort to develop clinical tools to rapidly diagnose pulmonary edema and track response to treatment has occurred. The ideal properties of such a tool would include high sensitivity and specificity, easy availability, and the ability to diagnose early accumulation of lung water before the development of the full clinical presentation. In addition, clinicians highly value the ability to precisely quantify extravascular lung water accumulation and differentiate hydrostatic from high permeability etiologies of pulmonary edema.
In this review, advances in understanding the physiology of extravascular lung water accumulation in health and in disease and the various mechanisms that protect against the development of pulmonary edema under physiologic conditions are discussed. In addition, the various bedside modalities available to diagnose early accumulation of extravascular lung water and pulmonary edema, including chest auscultation, chest roentgenography, lung ultrasonography, and transpulmonary thermodilution, are examined. Furthermore, advantages and limitations of these methods for the operating room and intensive care unit that are critical for proper modality selection in each individual case are explored
Inclusive Photoproduction of Mesons on Nuclei and the in-medium properties of the S Resonance
A relativistic non-local model for the inclusive photoproduction of
mesons from complex nuclei is introduced. The model is based on the dominance
of the S(1535) resonance. We compare the results of our calculations
with the available data on inclusive cross sections for the nuclei C, Al and
Cu. Assuming the resonance propagates freely in the nuclear medium, we find
that the calculated angular distribution and energy dependence of the cross
sections reproduce the data in a reasonable fashion. The present non-local
model allows the inclusion of density dependent mass and width in the
calculations. Including these in the calculations reveals that the presently
available data do not show clear preference for the inclusion of such
modifications of the properties of the S(1535) in the nuclear medium.Comment: 15 pages, 8 figure
Finite element analysis of gradient coil deformation and vibration in NMR microscopy
Resolution degradation due to gradient coil deformation and vibration in NMR microscopy is investigated using finite element analysis. From the analysis, deformations due to the Lorentz force can be as large as 1-10 μm depending on the gradient strength and coil frame material. Thus, these deformations can be one of the major resolution limiting factors in NMR microscopy. Coil vibration, which depends on the input current waveform and resolution degradation due to time-variant deformation and time-invariant deformation are investigated by numerical simulations
The Effect of Integrating Travel Time
This contribution demonstrates the potential gain for the quality of results
in a simulation of pedestrians when estimated remaining travel time is
considered as a determining factor for the movement of simulated pedestrians.
This is done twice: once for a force-based model and once for a cellular
automata-based model. The results show that for the (degree of realism of)
simulation results it is more relevant if estimated remaining travel time is
considered or not than which modeling technique is chosen -- here force-based
vs. cellular automata -- which normally is considered to be the most basic
choice of modeling approach.Comment: preprint of Pedestrian and Evacuation 2012 conference (PED2012)
contributio
Non-locality and Medium Effects in the Exclusive Photoproduction of Eta Mesons on Nuclei
A relativistic model for the quasifree exclusive photoproduction of
mesons on nuclei is extended to include both non-local and medium effects. The
reaction is assumed to proceed via the dominant contribution of the
S(1535) resonance. The complicated integrals resulting from the
non-locality are simplified using a modified version of a method given by
Cooper and Maxwell. The non-locality effects are found to affect the magnitude
of the cross section. Some possibilities reflecting the effects of the medium
on the propagation and properties of the intermediate S resonance are
studied. The effects of allowing the S to interact with the medium via
mean field scalar and vector potentials are considered. Both broadening of
width and reduction in mass of the resonance lead to a suppression of the
calculated cross sections.Comment: 19 pages, 7 figure
The Impact of the Extent of Lymphadenectomy on Oncologic Outcomes in Patients Undergoing Radical Cystectomy for Bladder Cancer : A Systematic Review
Copyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.Peer reviewedPostprin
A timeband framework for modelling real-time systems
Complex real-time systems must integrate physical processes with digital control, human operation and organisational structures. New scientific foundations are required for specifying, designing and implementing these systems. One key challenge is to cope with the wide range of time scales and dynamics inherent in such systems. To exploit the unique properties of time, with the aim of producing more dependable computer-based systems, it is desirable to explicitly identify distinct time bands in which the system is situated. Such a framework enables the temporal properties and associated dynamic behaviour of existing systems to be described and the requirements for new or modified systems to be specified. A system model based on a finite set of distinct time bands is motivated and developed in this paper
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Safety and efficacy of endoscopic submucosal dissection for rectal neoplasia: a multicenter North American experience.
Background and aims Rectal lesions traditionally represent the first lesions approached during endoscopic submucosal dissection (ESD) training in the West. We evaluated the safety and efficacy of rectal ESD in North America. Methods This is a multicenter retrospective analysis of rectal ESD between January 2010 and September 2018 in 15 centers. End points included: rates of en bloc resection, R0 resection, adverse events, comparison of pre- and post-ESD histology, and factors associated with failed resection. Results In total, 171 patients (median age 63 years; 56 % men) underwent rectal ESD (median size 43 mm). En bloc resection was achieved in 141 cases (82.5 %; 95 %CI 76.8-88.2), including 24 of 27 (88.9 %) with prior failed endoscopic mucosal resection (EMR). R0 resection rate was 74.9 % (95 %CI 68.4-81.4). Post-ESD bleeding and perforation occurred in 4 (2.3 %) and 7 (4.1 %), respectively. Covert submucosal invasive cancer (SMIC) was identified in 8.6 % of post-ESD specimens. There was one case (1/120; 0.8 %) of recurrence at a median follow-up of 31 weeks; IQR: 19-76 weeks). Older age and higher body mass index (BMI) were predictors of failed R0 resection, whereas submucosal fibrosis was associated with a higher likelihood of both failed en bloc and R0 resection. Conclusion Rectal ESD in North America is safe and is associated with high en bloc and R0 resection rates. The presence of submucosal fibrosis was the main predictor of failed en bloc and R0 resection. ESD can be considered for select rectal lesions, and serves not only to establish a definitive tissue diagnosis but also to provide curative resection for lesions with covert advanced disease
Relativistic Calculations for the Exclusive Photoproduction of Eta Mesons from Complex Nuclei
A relativistic model for the quasifree photoproduction of eta meson from
complex nuclei is developed. The interactions between fields are introduced
through effective Lagrangians. Contributions from several nucleon resonances as
well as nucleon Born terms and vector meson exchange diagrams are included.
Nucleon and eta wavefunctions are solutions of Dirac and Klein-Gordon
equations, respectively. Final state interactions of the outgoing particles are
included via optical potentials. The effects of these interactions on the cross
sections and photon asymmetries are studied and are found to be large.
Calculations indicate that at energies near threshold the exclusive reaction
takes place mainly through formation of the S_{11}(1535) resonance. Comparisons
with the non-relativistic calculations show differences between the two
approaches both for the cross sections and photon asymmetries. We give some
detailed predictions for the reaction observables for exclusive photoproduction
on ^{12}C, ^{16}O and ^{40}Ca.Comment: Latex, 27 pages, 13 uuencoded postscript figures. Accepted for
publication in Phys. Rev.
Does consultation improve decision-making?
This paper reports an experiment designed to test whether prior consultation within a group affects subsequent individual decision-making in tasks where demonstrability of correct solutions is low. In our experiment, subjects considered two paintings created by two different artists and were asked to guess which artist made each painting. We observed answers given by individuals under two treatments: In one, subjects were allowed the opportunity to consult with other participants before making their private decisions; in the other, there was no such opportunity. Our primary findings are that subjects in the first treatment evaluate the opportunity to consult positively, but they perform significantly worse and earn significantly less
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