Trends in outcomes from endovascular aortic repair over two decades

Endovascular therapy for aortic pathology has changed over the past two decades with the newer stent technologies. We examine the outcomes of endovascular aortic repair in a small subset of patients

Feasibility and Evaluation of Surgical Simulation with Developed Crisis Scenarios: A Comparison of Performance by Vascular Surgery Training Paradigms

OBJECTIVES: Surgical simulation is an integral component of training and has become increasingly vital in the evaluation and assessment of surgical trainees. Simulation proficiency determination has been traditionally based on accuracy and time to completion of various simulated tasks, but we were interested in assessing clinical judgment during a simulated crisis scenario. This study assessed the feasibility of creating a crisis simulator station for vascular surgery and evaluated the performance of vascular surgery integrated residents (0+5) and vascular surgery fellows (5+2) during a technical testing with an integrated crisis scenario. METHODS: A Modified Delphi method was used to create vascular surgery crisis simulation stations containing a clinical scenario in conjunction with either an open or endovascular simulator. Senior level vascular surgery trainees from both integrated residencies (0+5) and traditional vascular surgery fellowships (5+2) were then evaluated on two simulation stations: 1) Elective carotid endarterectomy (CEA) where the crisis is a postoperative stroke and 2) Endovascular aneurysm repair (EVAR) for a ruptured abdominal aortic aneurysm (rAAA). Each simulation had a crisis scenario incorporated into the procedure. Assessment was completed using a performance assessment tool containing a Likert scale. Total score was calculated as a percentage. Scores were also sub-divided in the following four categories: Situation Recognition and Decision-making, Procedural Flow, Technical Skills, and Interpretation and Use of Imaging Skills. Student\u27s t-test was used for analysis. RESULTS: 40 senior-level trainees were evaluated (27 fellows and 13 integrated residents) completing 80 simulations. The CEA crisis simulation yielded similar results between both groups (0+5 vs. 5+2, p = 1.00). The 0+5 residents in vascular surgery were graded to be more proficient in the EVAR for rAAA crisis simulation and demonstrated significant differences in Total Score (p = 0.04), Procedural Flow (p=0.03), and Interpretation and Use of Imaging Skills (p = 0.02). CONCLUSIONS: The creation of crisis-based simulation for trainees in vascular surgery is feasible and actionable. Integrated 0+5 residents performed similarly to 5+2 fellows on an open carotid endarterectomy (CEA) crisis simulation, but 0+5 residents scored significantly higher compared to traditional 5+2 fellows in an endovascular rAAA crisis simulation. Crisis simulation may offer better educational experiences and improved value compared to routine simulation. Further studies using different procedural models and clinical scenarios are needed to assess the validity of crisis simulation in vascular surgery and to better understand the performance disparities found between these training paradigms

Hand function is altered in individuals with a history of illicit stimulant use

Published: December 29, 2014Use of illicit stimulant drugs such as methamphetamine, cocaine, and ecstasy are a significant worldwide problem. However, little is known about the effect of these drugs on movement. The aim of the current study was to investigate hand function in adults with a history of illicit stimulant use. We hypothesized that prior use of illicit stimulant drugs is associated with abnormal manipulation of objects. The study involved 22 subjects with a history of illicit stimulant use (aged 29±8 yrs; time since last use: 1.8±4.0 yrs) and two control groups comprising 27 non-drug users (aged 25±8 yrs) and 17 cannabis users with no history of stimulant use (aged 22±5 yrs). Each subject completed screening tests (neuropsychological assessment, medical history questionnaire, lifetime drug history questionnaire, and urine drug screen) prior to gripping and lifting a light-weight object with the dominant right hand. Horizontal grip force, vertical lift force, acceleration, and first dorsal interosseus electromyographic (EMG) activity were recorded during three trials. In trial one, peak grip force was significantly greater in the stimulant group (12.8±3.9 N) than in the control groups (non-drug: 10.3±4.6 N; cannabis: 9.4±2.9 N, P<0.022). However, peak grip force did not differ between groups in trials two and three. The results suggest that individuals with a history of stimulant use overestimate the grip force required to manipulate a novel object but, are able to adapt grip force in subsequent lifts. The results suggest that movement dysfunction may be an unrecognized consequence of illicit stimulant use.Verity Pearson-Dennett, Stanley C. Flavel, Robert A. Wilcox, Dominic Thewlis, Adam P. Vogel, Jason M. White, Gabrielle Tod

Entanglement purification of unknown quantum states

A concern has been expressed that ``the Jaynes principle can produce fake entanglement'' [R. Horodecki et al., Phys. Rev. A {\bf 59}, 1799 (1999)]. In this paper we discuss the general problem of distilling maximally entangled states from $N$ copies of a bipartite quantum system about which only partial information is known, for instance in the form of a given expectation value. We point out that there is indeed a problem with applying the Jaynes principle of maximum entropy to more than one copy of a system, but the nature of this problem is classical and was discussed extensively by Jaynes. Under the additional assumption that the state $\rho^{(N)}$ of the $N$ copies of the quantum system is exchangeable, one can write down a simple general expression for $\rho^{(N)}$. We show how to modify two standard entanglement purification protocols, one-way hashing and recurrence, so that they can be applied to exchangeable states. We thus give an explicit algorithm for distilling entanglement from an unknown or partially known quantum state.Comment: 20 pages RevTeX 3.0 + 1 figure (encapsulated Postscript) Submitted to Physical Review

The speed of parietal theta frequency drives visuospatial working memory capacity

The speed of theta brain oscillatory activity is thought to play a key role in determining working memory (WM) capacity. Individual differences in the length of a theta cycle (ranging between 4 and 7 Hz) might determine how many gamma cycles (>30 Hz) can be nested into a theta wave. Gamma cycles are thought to represent single memory items; therefore, this interplay could determine individual memory capacity. We directly tested this hypothesis by means of parietal transcranial alternating current stimulation (tACS) set at slower (4 Hz) and faster (7 Hz) theta frequencies during a visuospatial WM paradigm. Accordingly, we found that 4-Hz tACS enhanced WM capacity, while 7-Hz tACS reduced WM capacity. Notably, these effects were found only for items presented to the hemifield contralateral to the stimulation site. This provides causal evidence for a frequency-dependent and spatially specific organization of WM storage, supporting the theta–gamma phase coupling theory of WM capacity

The dynamics and neural correlates of audio-visual integration capacity as determined by temporal unpredictability, proactive interference, and SOA

Over 5 experiments, we challenge the idea that the capacity of audio-visual integration need be fixed at 1 item. We observe that the conditions under which audio-visual integration is most likely to exceed 1 occur when stimulus change operates at a slow rather than fast rate of presentation and when the task is of intermediate difficulty such as when low levels of proactive interference (3 rather than 8 interfering visual presentations) are combined with the temporal unpredictability of the critical frame (Experiment 2), or, high levels of proactive interference are combined with the temporal predictability of the critical frame (Experiment 4). Neural data suggest that capacity might also be determined by the quality of perceptual information entering working memory. Experiment 5 supported the proposition that audio-visual integration was at play during the previous experiments. The data are consistent with the dynamic nature usually associated with cross-modal binding, and while audio-visual integration capacity likely cannot exceed uni-modal capacity estimates, performance may be better than being able to associate only one visual stimulus with one auditory stimulus

Measurement of the Spectral Shape of the beta-decay of 137Xe to the Ground State of 137Cs in EXO-200 and Comparison with Theory

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden non-unique $\beta$-decay transition ^{137}\textrm{Xe}(7/2^-)\to\,^{137}\textrm{Cs}(7/2^+). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultra-low background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal-to-background ratio of more than 99-to-1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden non-unique $\beta$-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.Comment: Version as accepted by PR