Automatic optimization of cardiac resynchronization therapy using SonR-rationale and design of the clinical trial of the SonRtip lead and automatic AV-VV optimization algorithm in the paradym RF SonR CRT-D (RESPOND CRT) trial.

Although cardiac resynchronization therapy (CRT) is effective in most patients with heart failure (HF) and ventricular dyssynchrony, a significant minority of patients (approximately 30%) are non-responders. Optimal atrioventricular and interventricular delays often change over time and reprogramming these intervals might increase CRT effectiveness. The SonR algorithm automatically optimizes atrioventricular and interventricular intervals each week using an accelerometer to measure change in the SonR signal, which was shown previously to correlate with hemodynamic improvement (left ventricular [LV] dP/dtmax). The RESPOND CRT trial will evaluate the effectiveness and safety of the SonR optimization system in patients with HF New York Heart Association class III or ambulatory IV eligible for a CRT-D device. Enrolled patients will be randomized in a 2:1 ratio to either SonR CRT optimization or to a control arm employing echocardiographic optimization. All patients will be followed for at least 24 months in a double-blinded fashion. The primary effectiveness end point will be evaluated for non-inferiority, with a nested test of superiority, based on the proportion of responders (defined as alive, free from HF-related events, with improvements in New York Heart Association class or improvement in Kansas City Cardiomyopathy Questionnaire quality of life score) at 12 months. The required sample size is 876 patients. The two primary safety end points are acute and chronic SonR lead-related complication rates, respectively. Secondary end points include proportion of patients free from death or HF hospitalization, proportion of patients worsened, and lead electrical performance, assessed at 12 months. The RESPOND CRT trial will also examine associated reverse remodeling at 1 year

Adaptive strategies of high-flying migratory hoverflies in response to wind currents: Flight behaviour of migrant hoverflies

Large migrating insects, flying at high altitude, often exhibit complex behaviour. They frequently elect to fly on winds with directions quite different from the prevailing direction, and they show a degree of common orientation, both of which facilitate transport in seasonally beneficial directions. Much less is known about the migration behaviour of smaller (10-70 mg) insects. To address this issue, we used radar to examine the high-altitude flight of hoverflies (Diptera: Syrphidae), a group of day-active, medium-sized insects commonly migrating over the UK. We found that autumn migrants, which must move south, did indeed show migration timings and orientation responses that would take them in this direction, despite the unfavourability of the prevailing winds. Evidently, these hoverfly migrants must have a compass (probably a time-compensated solar mechanism), and a means of sensing the wind direction (which may be determined with sufficient accuracy at ground level, before take-off). By contrast, hoverflies arriving in the UK in spring showed weaker orientation tendencies, and did not correct for wind drift away from their seasonally adaptive direction (northwards). However, the spring migrants necessarily come from the south (on warm southerly winds), so we surmise that complex orientation behaviour may not be so crucial for the spring movements

A nonlinear hydrodynamical approach to granular materials

We propose a nonlinear hydrodynamical model of granular materials. We show how this model describes the formation of a sand pile from a homogeneous distribution of material under gravity, and then discuss a simulation of a rotating sandpile which shows, in qualitative agreement with experiment, a static and dynamic angle of repose.Comment: 17 pages, 14 figures, RevTeX4; minor changes to wording and some additional discussion. Accepted by Phys. Rev.

Mechanisms for slow strengthening in granular materials

Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F_max experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time \tau. The layer strength increases roughly logarithmically with \tau -only- if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement measurements and by imaging of particle motion in the shear zone. Granular matter can strengthen due to a slow shift in the particle arrangement under shear stress. Humidity also leads to strengthening, but is found not to be its sole cause. In addition to these time dependent effects, the static friction coefficient can also be increased by compaction of the granular material under some circumstances, and by cycling of the applied shear stress.Comment: 21 pages, 11 figures, submitted to Phys. Rev.

The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour

Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect

The First VERITAS Telescope

The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.Comment: Accepted by Astroparticle Physic

Fantastically reasonable: ambivalence in the representation of science and technology in super-hero comics

A long-standing contrast in academic discussions of science concerns its perceived disenchanting or enchanting public impact. In one image, science displaces magical belief in unknowable entities with belief in knowable forces and processes and reduces all things to a single technical measure. In the other, science is itself magically transcendent, expressed in technological adulation and an image of scientists as wizards or priests. This paper shows that these contrasting images are also found in representations of science in super-hero comics, which, given their lowly status in Anglo-American culture, would seem an unlikely place to find such commonality with academic discourse. It is argued that this is evidence that the contrast constitutes an ambivalence arising from the dilemmas that science poses; they are shared rhetorics arising from and reflexively feeding a set of broad cultural concerns. This is explored through consideration of representations of science at a number of levels in the comics, with particular focus on the science-magic constellation, and enchanted and disenchanted imagery in representations of technology and scientists. It is concluded that super-hero comics are one cultural arena where the public meaning of science is actively worked out, an activity that unites “expert” and “non-expert” alike