Anisotropic pair correlations in binary and multicomponent hard-sphere mixtures in the vicinity of a hard wall: A combined density functional theory and simulation study

The fundamental measure approach to classical density functional theory has been shown to be a powerful tool to predict various thermodynamic properties of hard-sphere systems. We employ this approach to determine not only one-particle densities but also two-particle correlations in binary and six-component mixtures of hard spheres in the vicinity of a hard wall. The broken isotropy enables us to carefully test a large variety of theoretically predicted two-particle features by quantitatively comparing them to the results of Brownian dynamics simulations. Specifically, we determine and compare the one-particle density, the total correlation functions, their contact values, and the force distributions acting on a particle. For this purpose, we follow the compressibility route and theoretically calculate the direct correlation functions by taking functional derivatives. We usually observe an excellent agreement between theory and simulations, except for small deviations in cases where local crystal-like order sets in. Our results set the course for further investigations on the consistency of functionals as well as for structural analysis on, e.g., the primitive model. In addition, we demonstrate that due to the suppression of local crystallization, the predictions of six-component mixtures are better than those in bidisperse or monodisperse systems. Finally, we are confident that our results of the structural modulations induced by the wall lead to a deeper understanding of ordering in anisotropic systems in general, the onset of heterogeneous crystallization, caging effects, and glassy dynamics close to a wall, as well as structural properties in systems with confinement

Triple GEM Detectors for the Forward Tracker in STAR

Future measurements of the flavor-separated spin structure of the proton via parity-violating W boson production at RHIC require an upgrade of the forward tracking system of the STAR detector. This upgrade will allow the reconstruction of the charge sign of electrons and positrons produced from decaying W bosons. A design based on six large area triple GEM disks using GEM foils produced by Tech-Etch Inc. has emerged as a cost-effective solution to provide the necessary tracking precision. We report first results from a beam test of three test detectors using Tech-Etch produced GEM foils and a laser etched two dimensional strip readout. The detectors show good operational stability, high efficiency and a spacial resolution of around 70 um or better, exceeding the requirements for the forward tracking upgrade. The influence of the angle of incidence of the particles on the spatial resolution of the detectors has also been studied in detail.Comment: 5 pages, 8 figures, presented at the IEEE Nuclear Science Symposium in Honolulu, HI, USA, October 27 - November 3, 200

Dextran sulfate activates contact system and mediates arterial hypotension via B2 kinin receptors

To define some of the mechanisms underlying dextran sulfate (DXS)-induced hypotension, we investigated the effects of either the plasma kallikrein inhibitor des-Pro2-[Arg15] aprotinin (BAY x 4620) or the specific bradykinin B2-receptor antagonist Hoe-140 on the hypotensive response to DXS. In the first study, anesthetized miniature pigs were given DXS alone, DXS plus BAY x 4620 in various doses, or saline. As expected, DXS alone produced a profound but transient systemic arterial hypotension with a concomitant reduction in kininogen. Circulating kinin levels, complement fragment des-Arg-C3a, and fibrin monomer were all increased. Treatment with BAY x 4620 produced a dose-dependent attenuation of these effects with complete blockade of the hypotension as well as the observed biochemical changes at the highest dose (360 mg). In a second study, two groups of pigs were given either DXS alone or DXS plus Hoe-140. DXS-induced hypotension was completely blocked by Hoe-140 pretreatment; however, kininogen was again depleted. We conclude, therefore, that DXS-induced hypotension is produced by activation of plasma kallikrein that results in the production of bradykinin and that liberation of bradykinin and its action on B2 receptors in the vasculature are both necessary and sufficient to produce the observed effects on circulatory pressure

Telemedicine coverage for post-operative ICU patients.

Introduction There is an increased demand for intensive care unit (ICU) beds. We sought to determine if we could create a safe surge capacity model to increase ICU capacity by treating ICU patients in the post-anaesthesia care unit (PACU) utilizing a collaborative model between an ICU service and a telemedicine service during peak ICU bed demand. Methods We evaluated patients managed by the surgical critical care service in the surgical intensive care unit (SICU) compared to patients managed in the virtual intensive care unit (VICU) located within the PACU. A retrospective review of all patients seen by the surgical critical care service from January 1st 2008 to July 31st 2011 was conducted at an urban, academic, tertiary centre and level 1 trauma centre. Results Compared to the SICU group ( n = 6652), patients in the VICU group ( n = 1037) were slightly older (median age 60 (IQR 47-69) versus 58 (IQR 44-70) years, p = 0.002) and had lower acute physiology and chronic health evaluation (APACHE) II scores (median 10 (IQR 7-14) versus 15 (IQR 11-21), p \u3c 0.001). The average amount of time patients spent in the VICU was 13.7 + /-9.6 hours. In the VICU group, 750 (72%) of patients were able to be transferred directly to the floor; 287 (28%) required subsequent admission to the surgical intensive care unit. All patients in the VICU group were alive upon transfer out of the PACU while mortality in the surgical intensive unit cohort was 5.5%. Discussion A collaborative care model between a surgical critical care service and a telemedicine ICU service may safely provide surge capacity during peak periods of ICU bed demand. The specific patient populations for which this approach is most appropriate merits further investigation

Using the Default Option Bias to Influence Decision-Making While Driving

Gaining a better understanding of human–computer interaction in multiple-goal environments, such as driving, is critical as people increasingly use information technology to accomplish multiple tasks simultaneously. Extensive research shows that decision biases can be utilized as effective cues to guide user interaction in single-goal environments. This article is a first step toward understanding the effect of decision biases in multiple-goal environments. This study analyzed data from a field experiment during which a comparison was made between drivers’ decisions on parking lots in a single-goal environment and drivers’ decisions in a multiple-goal environment when being exposed to the default option bias. The article shows that the default option bias is effective in multiple-goal environments. The results have important implications for the design of human–computer interaction in multiple-goal environments

Electrical conductivity, ionic conductivity, optical absorption, and gas separation properties of ionically conductive polymer membranes embedded with Si microwire arrays

The optical absorption, ionic conductivity, electronic conductivity, and gas separation properties have been evaluated for flexible composite films of ionically conductive polymers that contain partially embedded arrays of ordered, crystalline, p-type Si microwires. The cation exchange ionomer Nafion, and a recently developed anion exchange ionomer, poly(arylene ether sulfone) that contains quaternary ammonium groups (QAPSF), produced composite microwire array/ionomer membrane films that were suitable for operation in acidic or alkaline media, respectively. The ionic conductivity of the Si wire array/Nafion composite films in 2.0 M H_(2)SO_4(aq) was 71 mS cm^(−1), and the conductivity of the Si wire array/QAPSF composite films in 2.0 M KOH(aq) was 6.4 mS cm^(−1). Both values were comparable to the conductivities observed for films of these ionomers that did not contain embedded Si wire arrays. Two Si wire array/Nafion membranes were electrically connected in series, using a conducting polymer, to produce a trilayer, multifunctional membrane that exhibited an ionic conductivity in 2.0 M H_(2)SO)4(aq) of 57 mS cm^(−1) and an ohmic electrical contact, with an areal resistance of ~0.30 Ω cm^2, between the two physically separate embedded Si wire arrays. All of the wire array/ionomer composite membranes showed low rates of hydrogen crossover. Optical measurements indicated very low absorption (<3%) in the ion-exchange polymers but high light absorption (up to 80%) by the wire arrays even at normal incidence, attesting to the suitability of such multifunctional membranes for application in solar fuels production

Spin-Dependent Electron Scattering from Polarized Protons and Deuterons with the BLAST Experiment at MIT-Bates

The Bates Large Acceptance Spectrometer Toroid (BLAST) experiment was operated at the MIT-Bates Linear Accelerator Center from 2003 until 2005. The experiment was designed to exploit the power of a polarized electron beam incident on polarized targets of hydrogen and deuterium to measure, in a systematic manner, the neutron, proton, and deuteron form factors as well as other aspects of the electromagnetic interaction on few-nucleon systems. We briefly describe the experiment, and present and discuss the numerous results obtained.United States. Dept. of EnergyNational Science Foundation (U.S.