Non-equilibrium states of a photon cavity pumped by an atomic beam

We consider a beam of two-level randomly excited atoms that pass one-by-one through a one-mode cavity. We show that in the case of an ideal cavity, i.e. no leaking of photons from the cavity, the pumping by the beam leads to an unlimited increase in the photon number in the cavity. We derive an expression for the mean photon number for all times. Taking into account leaking of the cavity, we prove that the mean photon number in the cavity stabilizes in time. The limiting state of the cavity in this case exists and it is independent of the initial state. We calculate the characteristic functional of this non-quasi-free non-equilibrium state. We also calculate the energy flux in both the ideal and open cavity and the entropy production for the ideal cavity.Comment: Corrected energy production calculations and made some changes to ease the readin

Interventions Highlighting Hypocrisy Reduce Collective Blame of Muslims for Individual Acts of Violence and Assuage Anti-Muslim Hostility

Collectively blaming groups for the actions of individuals can license vicarious retribution. Acts of terrorism by Muslim extremists against innocents, and the spikes in anti-Muslim hate crimes against innocent Muslims that follow, suggest that reciprocal bouts of collective blame can spark cycles of violence. How can this cycle be short-circuited? After establishing a link between collective blame of Muslims and anti-Muslim attitudes and behavior, we used an “interventions tournament” to identify a successful intervention (among many that failed). The “winning” intervention reduced collective blame of Muslims by highlighting hypocrisy in the ways individuals collectively blame Muslims—but not other groups (White Americans, Christians)—for individual group members’ actions. After replicating the effect in an independent sample, we demonstrate that a novel interactive activity that isolates the psychological mechanism amplifies the effectiveness of the collective blame hypocrisy intervention and results in downstream reductions in anti-Muslim attitudes and anti-Muslim behavior

Seismic design of boundary frame members of steel plate shear walls

ABSTRACT: Steel Plate Shear Walls (SPSWs), which consist of infill steel panels surrounded by columns, called Vertical Boundary Elements (VBEs), and beams, called Horizontal Boundary Elements (HBEs), are rapidly becoming an appealing alternative lateral force resisting system for building structures in the United States, Canada, Mexico, Japan, Taiwan and other countries. This paper presents results of some recent research to expand the range of applicability of SPSWs with emphasis on improving the understanding of seismic performance of the boundary frame members. Following a brief review of the observed failure of the intermediate HBE from the MCEER/NCREE testing program, the models developed to investigate the behavior of HBEs are presented, followed by design recommendations. Then, analytical models to prevent the in-plane shear yielding and to estimate the out-of-plane buckling strength of VBEs are developed, followed by a review of past experimental data to investigate if the previously observed VBE failures were due to excessive VBE flexibilities or other causes. It is shown that the existing VBE flexibility requirement specified in the current design codes is uncorrelated to satisfactory VBE performance. The proposed analytical models predict the performance of previously tested SPSWs that correlates well with the experimental observations

Objective determination of the predefined duration of a constant-load diagnostic tests in arterial claudication

OBJECTIVE: The predefined duration to arbitrarily stop the tests during constant-load treadmill exercise is a subject of debate and widely variable in the literature. We hypothesized that the upper and lower limits for predefined durations of constant-load 3.2 km/hour 10% grade tests could be derived from the distribution of walking distances observed on a treadmill in a population of subjects referred for claudication or from the optimal cutoff point distance on a treadmill to confirm a limitation self-reported by history.METHODS: We conducted a retrospective analysis using a referral center, institutional practice, and ambulatory patients. We studied 1290 patients (86% male), 62.1 +/- 11.2 years of age, 169 +/- 8 cm height, 75.7 +/- 14.2 kg weight. Patients performed a standard constant-load treadmill test: 3.2 km hour(-1), 10% slope, maximized to 1000 meters (approximately 20 minutes). We analyzed the maximal walking distance self-reported (MWD(SR)) by history and the maximal walking distance measured on the treadmill (MWD(TT)). Patients reporting MWD(SR) >or=1000 meters were considered unlimited by history. RESULTS: Only 197 patients (15.3%) completed the 20-minute treadmill test. Among the 504 patients who did not stop before 250 meters, 47.8% stopped within the next 250 meters (were unable to walk 500 meters). This proportion falls to 7.5% among the 213 patients who did not stop before 750 meters. When the final goal was to estimate whether the treadmill test can discriminate patients with or without limitation by history, area under the receiver operating characteristic (ROC) curve was 0.809 +/- 0.016 (95% confidence interval [CI], 0.778-0.841; P < .0001), the best diagnostic performance was attained for an MWD(TT) of 299 meters (approximately 6.15 minutes). CONCLUSION: In patients undergoing constant-load treadmill exercise with a protocol of 3.2 km hour(-1) and 10% slope: a predefined duration of 7 minutes could be proposed as a lower limit for the predefined duration of the tests specifically if one aims at confirming the limitation by history with treadmill testing. Owing to the low risk that patients that could walk 750 meters (approximately 15 minutes) will have to stop in the next 250 meters, 15 minutes seems a reasonable upper limit for the predefined test duration in clinical routine

Volume and diagnosis: an approach to cross-border care in eight European countries

Objectives: Mobility of patients is a pertinent issue on the European Union's agenda. This study aimed to estimate the volume and main diagnoses of cross-border care in eight European countries, in order to provide policy makers with background information about the nature of patient mobility in Europe. Methods: This article reports the combined findings from three independent studies that compiled self-reported information on admissions data and main diagnoses from more than 200 hospitals in eight European countries. Results: The average volume of cross-border patients accounted for less than 1% of total admissions in the hospitals studied here. Diseases of the circulatory system (mainly acute myocardial infarction) and fractures were the most common reasons for hospitalisation of European patients abroad. Deliveries and other diagnoses related to pregnancy, pneumonia, appendicitis and other diseases of the digestive system, aftercare procedures, and disorders of the eye and adnexa were also common diagnoses for this population. Conclusions: Hospitals should reinforce their efforts to adapt the care provided to the needs of foreign patients in treatment areas that cover the most frequent pathologies identified in this populatio

A Three-Frequency Feed for Millimeter-Wave Radiometry

A three-frequency millimeter-wave feed horn was developed as part of an advanced component technology task that provides components necessary for higher-frequency radiometers to meet the needs of the Surface Water and Ocean Topography (SWOT) mission. The primary objectives of SWOT are to characterize ocean sub-mesoscale processes on 10-km and larger scales in the global oceans, and to measure the global water storage in inland surface water bodies, including rivers, lakes, reservoirs, and wetlands. In this innovation, the feed provides three separate output ports in the 87-to- 97-GHz, 125-to-135-GHz, and 161-to-183- GHz bands; WR10 for the 90-GHz channel, WR8 for the 130-GHz channel, and WR5 for the 170-GHz channel. These ports are in turn connected to individual radiometer channels that will also demonstrate component technology including new PIN-diode switches and noise diodes for internal calibration integrated into each radiometer front end. For this application, a prime focus feed is required with an edge taper of approximately 20 dB at an illumination angle of 40 deg. A single polarization is provided in each band. Preliminary requirements called for a return loss of better than 15 dB, which is achieved across all three bands. Good pattern symmetry is also obtained throughout all three-frequency bands. This three-frequency broadband millimeter-wave feed also minimizes mass and provides a common focal point for all three millimeter-wave bands

Zitterbewegung and semiclassical observables for the Dirac equation

In a semiclassical context we investigate the Zitterbewegung of relativistic particles with spin 1/2 moving in external fields. It is shown that the analogue of Zitterbewegung for general observables can be removed to arbitrary order in \hbar by projecting to dynamically almost invariant subspaces of the quantum mechanical Hilbert space which are associated with particles and anti-particles. This not only allows to identify observables with a semiclassical meaning, but also to recover combined classical dynamics for the translational and spin degrees of freedom. Finally, we discuss properties of eigenspinors of a Dirac-Hamiltonian when these are projected to the almost invariant subspaces, including the phenomenon of quantum ergodicity