On acceleration of Krylov-subspace-based Newton and Arnoldi iterations for incompressible CFD: replacing time steppers and generation of initial guess

We propose two techniques aimed at improving the convergence rate of steady state and eigenvalue solvers preconditioned by the inverse Stokes operator and realized via time-stepping. First, we suggest a generalization of the Stokes operator so that the resulting preconditioner operator depends on several parameters and whose action preserves zero divergence and boundary conditions. The parameters can be tuned for each problem to speed up the convergence of a Krylov-subspace-based linear algebra solver. This operator can be inverted by the Uzawa-like algorithm, and does not need a time-stepping. Second, we propose to generate an initial guess of steady flow, leading eigenvalue and eigenvector using orthogonal projection on a divergence-free basis satisfying all boundary conditions. The approach, including the two proposed techniques, is illustrated on the solution of the linear stability problem for laterally heated square and cubic cavities

Recurrent lower gastrointestinal bleeding from idiopathic ileocolonic varices: a case report

<p>Abstract</p> <p>Introduction</p> <p>Varices of the colon are a rare cause of lower gastrointestinal bleeding, usually associated with portal hypertension due to liver cirrhosis or other causes of portal venous obstruction. Idiopathic colonic varices are extremely rare. Recognition of this condition is important as idiopathic colonic varices may be a cause of recurrent lower gastrointestinal bleeding.</p> <p>Case presentation</p> <p>We report the case of a 21-year-old Asian man from north India who presented with recurrent episodes of lower gastrointestinal bleeding. Colonoscopy revealed varices involving the terminal ileum and colon to the sigmoid. Thorough evaluation was undertaken to rule out any underlying portal hypertension. Our patient underwent subtotal colectomy including resection of involved terminal ileum and an ileorectal anastomosis.</p> <p>Conclusion</p> <p>Colonic varices are an uncommon cause of lower gastrointestinal bleeding. Idiopathic colonic varices are diagnosed after excluding underlying liver disease and portal hypertension. Recognition of this condition is important as prognosis is good in the absence of liver disease and is curable by resection of the involved bowel.</p

Skills training in minimally invasive surgery in Dutch obstetrics and gynecology residency curriculum

The complexity of acquiring minimally invasive surgical (MIS) skills, combined with smaller case volumes for residents have pushed the development of skills training facilities on simulators outside the operating room (OR). Medico-legal and financial constraints have stimulated this development even more. However, the implementation of simulator training into a residency curriculum is shown to be troublesome. MIS skills training is organized in a uniform and easily applicable way in the Dutch obstetrics and gynecology residency curriculum. Every resident is obliged to attend the same basic surgical skills course, named Cobra-alpha course, intentionally during postgraduate year (PGY) 1 or 2. Furthermore, surgical skills are trained, evaluated and expanded on simulators in teaching hospitals. Additional to the Cobra-alpha course, residents may attend advanced training courses and congresses focusing on laparoscopy and hysteroscopy. This organization guarantees a uniform introduction to MIS skills training for every resident. However, preconditions for continuous training and evaluation after this introduction have to be optimized

Retention of basic laparoscopic skills after a structured training program

The purpose of this study was to test the retention of basic laparoscopic skills on a box trainer 1 year after a short training program. For a prior study, eight medical students without prior experience (novices) underwent baseline testing, followed by five weekly training sessions and a final test. During each of seven sessions, they performed five tasks on an inanimate box trainer. Scores were calculated by adding up the time to completion of the task with penalty points, consequently rewarding speed and precision. The sum score was the sum of the five scores. One year later, seven of them underwent retention testing for the current study. The final test results were compared with retention test results as a measure of durability of acquired skills. Novices’ scores did not worsen significantly for four out of five tasks (i.e., placing a pipe cleaner p = 0.46, placing beads p = 0.24, cutting a circle p = 0.31, and knot tying p = 0.13). However, deterioration was observed in the performance on stretching a rubber band (p < 0.05), as well as in the sum score (p < 0.05). Nevertheless, all retention scores remained better than the baseline results. In conclusion, basic laparoscopic skills acquired during a short training program merely sustain over time. However, ongoing practice is advisable, especially to preserve tissue-handling skills, since these may be the first to deteriorate

Laparoscopic Video Analysis for Training and Image Guided Surgery

Automatic analysis of Minimally Invasive Surgical video has the potential to drive new solutions for alleviating needs of safe and reproducible training programs, objective and transparent evaluation systems and navigation tools to assist surgeons and improve patient safety. Surgical video is an always available source of information, which can be used without any additional intrusive hardware in the operating room. This paper is focused on surgical video analysis methods and techniques. It describes authors' contributions in two key aspects, the 3D reconstruction of the surgical field and the segmentation and tracking of tools and organs based on laparoscopic video images. Results are given to illustrate the potential of this field of research, like the calculi of the 3D position and orientation of a tool from its 2D image, or the translation of a preoperative resection plan into a hepatectomy surgical procedure using the shading information of the image. Research efforts are required to further develop these technologies in order to harness all the valuable information available in any video-based surgery

Production properties of K*(892) vector mesons and their spin alignment as measured in the NOMAD experiment

First measurements of K*(892) mesons production properties and their spin alignment in nu_mu charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For K*+ and K*- mesons produced in nu_mu CC interactions and decaying into K0 pi+/- we have found the following yields per event: (2.6 +/- 0.2 (stat.) +/- 0.2 (syst.))% and (1.6 +/- 0.1 (stat.) +/- 0.1 (syst.))% respectively, while for the K*+ and K*- mesons produced in nu NC interactions the corresponding yields per event are: (2.5 +/- 0.3 (stat.) +/- 0.3 (syst.))% and (1.0 +/- 0.3 (stat.) +/- 0.2 (syst.))%. The results obtained for the rho00 parameter, 0.40 +/- 0.06 (stat) +/- 0.03 (syst) and 0.28 +/- 0.07 (stat) +/- 0.03 (syst) for K*+ and K*- produced in nu_mu CC interactions, are compared to theoretical predictions tuned on LEP measurements in e+e- annihilation at the Z0 pole. For K*+ mesons produced in nu NC interactions the measured rho00 parameter is 0.66 +/- 0.10 (stat) +/- 0.05 (syst).Comment: 20 p

Pilot, randomized, placebo-controlled clinical field study to evaluate the effectiveness of bupivacaine liposome injectable suspension for the provision of post-surgical analgesia in dogs undergoing stifle surgery

Abstract Background Local anesthetics are an important component of perioperative pain management, but the duration of action of available products is limited. We hypothesized that a single local infiltration of a novel bupivacaine liposome injectable suspension (AT-003) would provide clinically effective analgesia over a 72-h period. In a masked, randomized, placebo-controlled, multi-center pilot field study, dogs undergoing lateral retinacular suture placement for cranial cruciate insufficiency were randomly assigned to surgical site infiltration with AT-003 (5.3 mg/kg) or an equivalent volume of saline. Infiltration of the surgical site was done prior to closure. Primary outcome measure was the Glasgow Composite Measure Pain Scale (CMPS-SF) assessed prior to surgery and at 2, 4, 8, 12, 24, 30, 36, 48, 54, 60 and 72 h following surgery by trained individuals. Provision for rescue analgesia was employed. Repeated measures analysis of variance were utilized to test for possible differences between treatment groups and a success/failure analysis was also employed, based on the need for rescue analgesia. Results Forty-six dogs were enrolled and evaluated. For CMPS-SF scores there was a significant overall treatment effect (p = 0.0027) in favor of AT-003. There were significantly more successes in the AT-003 group compared to placebo over each time period (p = 0.0001 for 0–24 h, p = 0.0349 for 0–48 h, and p = 0.0240 for 0-72 h). No significant adverse events were seen. Conclusions AT-003 (bupivacaine liposome injectable suspension) provided measurable local analgesia over a 72-h period following post-stifle surgery surgical site tissue infiltration. Further work is indicated to develop this product for clinical use

"Am I really ready to go home?" : a qualitative study of patients' experience of early discharge following an Enhanced Recovery Programme for Liver Resection Surgery

This qualitative data demonstrates some of the complexities of patients' expectations and experiences of the ERP. Whilst patients generally experience the ERP positively, they also have concerns about the process. The study highlights areas where additional support may be needed for patients enrolled in ERPs and discharged early

Physician reported perception in the treatment of high blood pressure does not correspond to practice

<p>Abstract</p> <p>Background</p> <p>High blood pressure is a significant health problem world-wide. Physician factors play a significant role in the suboptimal control of hypertension in the United States. We sought to better understand primary care physician's opinions regarding use of hypertension guidelines, patient and physician related barriers to treatment and physician treatment decision making in the management of hypertension as part of a first step in developing research tools and interventions designed to address these issues.</p> <p>Methods</p> <p>An IRB approved survey pertaining to physician opinion regarding the treatment of hypertension. Items consisted of questions regarding: 1) knowledge of hypertension treatment guidelines; 2) barriers to hypertension control (physician vs. patient); and 3) self-estimation of physician treatment of hypertension. Descriptive Statistics were used to describe results.</p> <p>Results</p> <p>All physicians were board certified in family or general internal medicine (n = 28). Practices were located in urban (n = 12), suburban (n = 14) and inner city locations (n = 1). All physicians felt they did a good job of treating hypertension. Most physicians felt the biggest barrier to hypertension control was patient non-compliance. Half of physicians would fail to intensify treatment for hypertension when blood pressure was above recommended levels for all disease states studied (essential hypertension, heart disease, diabetes, and renal disease).</p> <p>Conclusion</p> <p>Physician ability to assess personal performance in the treatment of hypertension and physician opinion that patient noncompliance is the greatest barrier to optimal hypertension control is contradictory to reported practice behavior. Optimal blood pressure control requires increased physician understanding on the evaluation and management of blood pressure. These data provide crucial formative data to enhance the content validity of physician education efforts currently underway to improve the treatment of blood pressure in the primary care setting.</p