1,264 research outputs found
Two Scale FE Simulation of Coated Forming Tools under Thermo-Mechanical Loading
Modern trends and challenges in manufacturing processes have led to an increasing complexity of hybrid forming processes in the last couple of years. Besides the improvement of the thermo-mechanical process chain the application of coated forming tools plays a crucial role in actual developments. Considering machining processes in general the investigation of tools experienced a secondary role in the past. For example, in numerical simulations of manufacturing processes tools are often modelled as rigid bodies. To remedy, this paper introduces a two scale finite element model for the coating system of a coated hybrid forming tool. Within this concept individual coating layers are considered on the mesocale and macroscopic results for the coating elements are obtained using volume averaging procedures. Two numerical examples using an implicit and an explicit integration scheme show the capability of the model to be applied for a coated forming tool subjected to thermo-mechanical loading conditions
Intoxicated eyewitnesses:the effect of a fully balanced placebo design on event memory and metacognitive control
Few studies have examined the impact of alcohol on metacognition for witnessed events. We used a 2x2 balanced placebo design, where mock-witnesses expected and drank alcohol, did not expect but drank alcohol, did not expect nor drank alcohol, or expected but did not drink alcohol. Participants watched a mock-crime in a bar-lab, followed by free recall and a cued-recall test with or without the option to reply ‘don’t know’ (DK). Intoxicated mock-witnesses’ free recall was less complete but not less accurate. During cued-recall, alcohol led to lower accuracy, and reverse placebo participants gave more erroneous and fewer correct responses. Permitting and clarifying DK responses was associated with fewer errors and more correct responses for sober individuals; and intoxicated witnesses were less likely to opt out of erroneous responding to unanswerable questions. Our findings highlight the practical and theoretical importance of examining pharmacological effects of alcohol and expectancies in real-life settings
The Impact of Testing on the Formation of Children's and Adults' False Memories
Witnesses are frequently questioned immediately following a crime. The effects of such testing on false recall are inconclusive: Testing may inoculate against subsequent misinformation or enhance false memory formation. We examined whether different types of processing can account for these discrepancies. Drawing from Fuzzy-trace and Associative-activation theories, immediate questions that trigger the processing of the global understanding of the event can heighten false memory rates. However, questions that trigger the processing of specific details can inoculate memories against subsequent misinformation. These effects were hypothesized to be more pronounced in children than in adults. Seven/eight-, 11/12-, 14/15-year-olds, and adults (N = 220) saw a mock-theft film and were tested immediately with meaning or item-specific questions. Test results on the succeeding day replicated classic misinformation and testing effects, although our processing hypothesis was not supported. Only adults who received meaning questions benefited from immediate testing and, across all ages, testing led to retrieval-enhanced suggestibility
Securing the appendiceal stump in laparoscopic appendectomy: Evidence for routine stapling?
Background: This metaanalysis aimed to compare endoscopic linear stapling and loop ligatures used to secure the base of the appendix. Methods: Randomized controlled trials on appendix stump closure during laparoscopic appendectomy were systematically searched and critically appraised. The results in terms of complication rates, operating time, and hospital stay were pooled by standard metaanalytic techniques. Results: Data on 427 patients from four studies were included. The operative time was 9 min longer when loops were used (p = 0.04). Superficial wound infections (odds ratio [OR], 0.21; 95% confidence interval (CI), 0.06-0.71; p = 0.01) and postoperative ileus (OR, 0.36; 95% CI, 0.14-0.89; p = 0.03) were significantly less frequent when the appendix stump was secured with staples instead of loops. Of 10 intraoperative ruptures of the appendix, 7 occurred in loop-treated patients (p = 0.46). Hospital stay and frequency of postoperative intraabdominal abscess also were comparable in loop-treated and staple-treated patients. Conclusions: The clinical evidence on stump closure methods in laparoscopic appendectomy favors the routine use of endoscopic staplers
Reconstruction of the gastric passage by a side-to-side gastrogastrostomy after failed vertical-banded gastroplasty: a case report
INTRODUCTION: Vertical-banded gastroplasty, a technique that is commonly performed in the treatment of morbid obesity, represents a nonadjustable restrictive procedure which reduces the volume of the upper stomach by a vertical stapler line. In addition, a textile or silicone band restricts food passage through the stomach. CASE PRESENTATION: A 71-year-old woman presented with a severe gastric stenosis 11 years after vertical gastroplasty. We describe a side-to-side gastrogastrostomy as a safe surgical procedure to restore the physiological gastric passage after failed vertical-banded gastroplasty. CONCLUSION: Occasionally, restrictive procedures for morbid obesity cannot be converted into an alternative bariatric procedure to maintain weight control. This report demonstrates that a side-to-side gastrogastrostomy is a feasible and safe procedure
О фундаментальных проблемах исследования задач термодинамики и тепломассопереноса в нефтегазовой отрасли
Short- and Long-Term Results of Open Versus Laparoscopic Appendectomy
Clinical advantages of laparoscopic appendectomy have been shown in numerous trials and reviews. Most of these advantages are small and of limited clinical relevance, while laparoscopic operation costs are reported to be higher. The present study compares short- and long-term results of conventional appendectomy with or without diagnostic laparoscopy (OA), and laparoscopic appendectomy (LA). All adult patients who underwent appendectomy in our institution from 1995 to 2005 were included retrospectively. Patient data were retrieved from medical records, questionnaires sent by mail, and records of general practitioners. Primary outcome parameters were long-term complications, readmissions, and reinterventions (> 30 days postoperatively). Secondary outcome parameters were short-term complications, readmissions, and reinterventions (a parts per thousand currency sign30 days postoperatively). A total of 755 patients were included, 545 of whom underwent OA, with the remaining 210 undergoing LA. In the long term there were few complications noted, and there were no significant differences in complications between the two groups. Within 30 days postoperatively, LA was associated with a significantly higher incidence of abdominal abscesses with consequent diagnostic investigations, interventions, and readmissions. Although laparoscopic appendectomy is known to deliver clinical advantages, it is associated with a higher incidence of abdominal abscesses. Because the procedure is about to become the standard of care, future research must be directed at solving this issue. The expected lower incidence of incisional hernia and small bowel obstruction after laparoscopic appendectomy was not shown in the present stud
The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)
The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here
Highly Enantioselective Conjugate Addition of Thiols using Mild Scandium Triflate Catalysis
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