A heuristic model of bounded route choice in urban areas

There is substantial evidence to indicate that route choice in urban areas is complex cognitive process, conducted under uncertainty and formed on partial perspectives. Yet, conventional route choice models continue make simplistic assumptions around the nature of human cognitive ability, memory and preference. In this paper, a novel framework for route choice in urban areas is introduced, aiming to more accurately reflect the uncertain, bounded nature of route choice decision making. Two main advances are introduced. The first involves the definition of a hierarchical model of space representing the relationship between urban features and human cognition, combining findings from both the extensive previous literature on spatial cognition and a large route choice dataset. The second advance involves the development of heuristic rules for route choice decisions, building upon the hierarchical model of urban space. The heuristics describe the process by which quick, 'good enough' decisions are made when individuals are faced with uncertainty. This element of the model is once more constructed and parameterised according to findings from prior research and the trends identified within a large routing dataset. The paper outlines the implementation of the framework within a real-world context, validating the results against observed behaviours. Conclusions are offered as to the extension and improvement of this approach, outlining its potential as an alternative to other route choice modelling frameworks

Nutcracker phenomenon presenting as left varicocele.

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A simple method of treating seromas involving modified Blalock-Taussig shunts

We treated seromas developing in two patients in relation to left-sided modified Blalock-Taussig shunts by reattaching the original graft to the descending aorta. We postulate that seromas may develop because of the large area of contact between the graft and blood. Shortening the length of the Gore-Tex graft may therefore be a feasible treatment.published_or_final_versio

Diagnosing deep vein thrombosis in the lower extremity: correlation of clinical and duplex scan findings.

OBJECTIVE: To identify factors that predict a positive duplex scan examination result in patients with suspected deep vein thrombosis of the lower extremity. DESIGN: Retrospective study. SETTING: Vascular laboratory in a university teaching hospital. PATIENTS AND METHODS: The results of 345 lower extremity duplex venous scans performed between August 1994 and November 1998 were reviewed. All patients were in-patients referred from different specialties due to clinical suspicion of lower extremity deep vein thrombosis. Positive duplex scans were correlated with patients' demographic data (sex, age), medical history (history of malignancy, deep vein thrombosis, and pulmonary embolism) and clinical features (leg swelling, venous insufficiency, calf pain, and leg ulcer). Univariate analysis was performed using the Chi squared test. RESULTS: A total of 345 scans were performed for 313 patients. The mean age was 55 years (range, 19-92 years). Sixty-three patients (49 male, 14 female) had a positive scan, giving a yield of 18.3%. Four factors had a significant association with a positive scan: male sex (P=0.0102), history of malignancy (P=0.0040), history of deep vein thrombosis (P=0.0001), and history of pulmonary embolism (P=0.0265). CONCLUSIONS: Common presenting clinical features do not predict the result of ultrasonographic investigation for deep vein thrombosis. The chance of having a positive scan is significantly higher in male patients and those with a history of malignancy, deep vein thrombosis, or pulmonary embolism.published_or_final_versio

Brush Handwriting Treatment of Emotional Problems in Patients with Type II Diabetes

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Treatment of a ruptured iliac aneurysm with an endoluminal stent graft.

The management of a 79-year-old man presenting with a ruptured common iliac aneurysm is described. The patient had multiple medical problems including hypertension, ischaemic heart disease, and atrial fibrillation, as well as a left hemispheric stroke 5 years previously. Traditional open surgery was judged unsuitable in this case because of the predicted poor outcome. The patient was subsequently treated successfully with endoluminal stent grafting.published_or_final_versio

Perioperative use of statins in noncardiac surgery

Background: Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) can significantly decrease cardiovascular mortality and morbidity, irrespective of the patients' cholesterol status. This paper reviews the effects of perioperative statin therapy in patients undergoing noncardiac surgery. Method: A systematic literature review was undertaken of all published literature on this subject using Medline and cross-referenced. All published relevant papers on the perioperative use of statins were used. Results: Perioperative statin therapy is associated with a lower perioperative morbidity and mortality in patients undergoing elective or emergency surgery. The effects are due to a combination of lipid-lowering and pleiotropic properties of statins. Conclusion: Ideally a large scale multi-centre randomized controlled trial of perioperative statin therapy should be performed but this may be difficult to conduct since there is already overwhelming evidence in the literature to suggest perioperative cardiovascular protective properties. Statins may still be under-prescribed in surgical patients. © 2008 Chan et al, publisher and licensee Dove Medical Press Ltd.published_or_final_versio

Variation of microphysics in wind bubbles: an alternative mechanism for explaining the rebrightenings in Gamma-ray burst afterglows

Conventionally, long Gamma-ray bursts (GRBs) are thought to be caused by the core collapses of massive stars. During the lifetime of a massive star, a stellar wind bubble environment should be produced. Furthermore, the microphysics shock parameters may vary along with the evolution of the fireball. Here, we investigate the variation of the microphysics shock parameters under the condition of wind bubble environment, and allow the microphysics shock parameters to be discontinuous at shocks in the ambient medium. It is found that our model can acceptably reproduce the rebrightenings observed in GRB afterglows, at least in some cases. The effects of various model parameters on rebrightenings are investigated. The rebrightenings observed in both the R-band and X-ray afterglow light curves of GRB 060206, GRB 070311 and GRB 071010A are reproduced in this model. © 2009 The Authors. Journal compilation © 2009 RAS.postprin

Successful endovascular infrarenal aneurysm repair in a patient with situs inversus totalis

Situs inversus totalis is a rare autosomal recessive developmental anomaly. There are very few reports in the published literature of abdominal aortic aneurysm in patient with situs inversus totalis, all of whom underwent open aneurysm repair. This is the first case in the world's literature to describe a patient with situs inversus totalis who had a successful endovascular infrarenal aneurysm repair. Although endovascular infrarenal aneurysm repair should not be more challenging, the endovascular approach may decrease risk of potential errors because of unfamiliar anatomy. Technical considerations in performing endovascular procedures in patients with situs inversus totalis are discussed in this article. © Annals of Vascular Surgery Inc.postprin