462 research outputs found
Fractal methods in image analysis and coding
In this thesis we present an overview of image processing techniques which use fractal methods in some way. We show how these fields relate to each other, and examine various aspects of fractal methods in each area.
The three principal fields of image processing and analysis th a t we examine are texture classification, image segmentation and image coding.
In the area of texture classification, we examine fractal dimension estimators, comparing these methods to other methods in use, and to each other. We attempt to explain why differences arise between various estimators of the same quantity. We also examine texture generation methods which use fractal dimension to generate textures of varying complexity.
We examine how fractal dimension can contribute to image segmentation methods. We also present an in-depth analysis of a novel segmentation scheme based on fractal coding.
Finally, we present an overview of fractal and wavelet image coding, and the links between the two. We examine a possible scheme involving both fractal and wavelet methods
Predicting risk of postpartum haemorrhage : a systematic review
Funding This study received no external or specific source of funding.Peer reviewedPublisher PD
Estimation of minimally important differences in EQ-5D utility and VAS scores in cancer
We wish to correct a mistake in the abstract and conclusion of our published paper [1]. In the abstract and conclusion, the MID for EQ-VAS score should be reported as 7 rather than 0.07. EQ-VAS scores range from 0 to 100, while EQ-5D index-based scores are anchored by 0 (dead) and 1 (perfect health). The specific wording in the conclusion of the abstract should read “Important differences in EQ-5D utility and VAS scores were similar for all cancers and lung cancer, with the lower end of the range of estimates closer to the MID, i. e. 0.08 for UK-index scores, 0.06 for US-index scores, and 7 for VAS scores. Author details
Gastrointestinal Foreign Bodies
Retained foreign bodies within the gastrointestinal tract (GIT) are common emergency presentations. The majority will pass spontaneously or be removed endoscopically, but a few selected cases may require emergency surgery for removal. This chapter reviews the management of foreign bodies within the GIT including both instances of foreign body ingestions and foreign body insertions. The scope of this chapter is not limited to evidence‐based data on selection of cases for conservative management but also includes data on endoscopic and surgical management
Radon, From the Ground into Our Schools: Parent/Guardian Awareness of Radon Levels in Vermont Schools
Introduction. Radon is the leading cause of lung cancer among non-smokers. Ex- posure to radon in schools may be harmful to schoolchildren, faculty, and staff, but there is currently no legislation mandating testing or mitigation of radon levels in Vermont schools.
Objectives. The goal of our study was to assess Vermont parents’ awareness of radon’s harmful effects, as well as awareness of and support for testing and mitigation of radon levels in their children’s schools.
Methods. We distributed paper and online surveys to Vermont parents of children grades K-12. 126 surveys were received and quantitatively analyzed. We held a focus group of two Vermont parents to gather qualitative data.
Results. Most surveyed parents demonstrated general knowledge of radon, but only 51% believed that radon affects the lungs. 8% were confident that their children’s schools had informed them about radon levels. 91.2% believe their children’s schools should take action to address elevated radon levels and 87% would support mandated mitigation. There is some concern and lack of knowledge about the financial implications of radon mitigation.
Conclusions. Most Vermont parents of children grades K-12 are unaware that radon is a lung carcinogen and do not know their children’s school’s radon levels or mitigation status. However, most are in favor of legislation that would require testing and dis- closure of schools’ high radon levels. Educating parents about school radon levels and their association with lung cancer could be a foundation for community support of legislation that mandates testing and mitigation of radon in Vermont schools.https://scholarworks.uvm.edu/comphp_gallery/1252/thumbnail.jp
Towards inclusive service delivery through social investment in England. An analysis of five sectors, with a particular focus on mental health
This report examines trends in social investment in England following the financial crisis of 2007/8. The first section considers social investment in relation to four policy arenas: housing, financial services, early childhood education and care, and water. The second part of the report provides an overview of social investment and disinvestment trends in the healthcare system in England since the 1990s with a particular focus on mental health services. This section includes a detailed account of service users’ and professionals’ experiences of the impact of liberalisation and austerity measures on mental health service delivery drawing on qualitative data collection. Throughout the report we identify policy recommendations to address the effects and impacts of emergent trends towards social disinvestment and liberalisation of public services. This study is part of the wider pan-European RE-InVEST project to investigate the impact of the EU Social Investment package on marginalised groups since the 2007 crisis
Environmental interventions to reduce fear of crime: systematic review of effectiveness
Background: Fear of crime is associated with negative health and wellbeing outcomes, and may mediate some impacts of the built environment on public health. A range of environmental interventions have been hypothesized to reduce the fear of crime.
Methods: This review aimed to synthesize the literature on the effectiveness of interventions in the built environment to reduce the fear of crime. Systematic review methodology, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance, was used. Studies of environmental interventions which reported a fear of crime outcome and used any prospective evaluation design (randomized controlled trial (RCT), trial or uncontrolled before-and-after study) were included. Eighteen databases were searched. The Hamilton tool was used to assess quality. A narrative synthesis of findings was undertaken.
Results: A total of 47 studies were included, 22 controlled and 25 uncontrolled, with total sample sizes ranging from n = 52 to approximately n = 23,000. Thirty-six studies were conducted in the UK, ten studies in the USA and one study in the Netherlands. The quality of the evidence overall is low. There are some indications that home security improvements and non-crime-related environmental improvements may be effective for some fear of crime outcomes. There is little evidence that the following reduce fear of crime: street lighting improvements, closed-circuit television (CCTV), multi-component environmental crime prevention programs or regeneration programs.
Conclusions: There is some evidence for the effectiveness of specific environmental interventions in reducing some indicators of fear of crime, but more attention to the context and possible confounders is needed in future evaluations of complex social interventions such as these
Pulmonary arterial pressures, arterial blood-gas tensions, and serum biochemistry of beef calves born and raised at high altitude
Includes bibliographical references (page 8).High-altitude exposure is physiologically challenging. This is particularly true for animals native to low-altitude environments, such as British breeds of cattle. The objective of this study was to document the effect of high altitude on select physiological parameters of healthy beef calves (Bos taurus) born and raised on a high-altitude ranch typical of the Rocky Mountain region. Pulmonary arterial pressures, arterial blood-gas tensions, serum biochemistry, and hematocrit were evaluated. The calves studied were a composite of British (50%-75%) and Continental (25-50%) breeds born on one ranch at an altitude of 2410 m. Calves were sampled at an altitude of 2410 m when 1 month old and again at an altitude of 2730 m when 3 and 6 months old. Between 3 and 6 months of age, calves had access to grazing from 2730 m to approximately 3500 m above sea level. On each occasion, 16 to 50 calves were sampled. Only calves that remained healthy throughout all three testing periods were included in the dataset. Calves with the highest pulmonary arterial pressures at 1 month of age tended to have the highest pressures at 6 months of age (r = 0.43, P = 0.16, n = 12). Respiratory alkalosis was greatest at 6 months of age (pH 7.48 ± 0.06). Mean alveolar-arterial oxygen pressure gradients were 11.7and 11.6 mmHg at 3 and 6 months of age, indicating poor transfer of oxygen from the alveoli into the pulmonary blood. Median values for blood lactate ranged from 1.4 to 3.4 mmol/L indicating substantial anaerobic respiration at all ages. Mean hematocrits were ≤ 35.7%, only slightly higher than values obtained from age-matched calves at sea level. These results suggest that the provision of oxygen to the peripheral tissues of beef calves may be compromised at altitudes over 2410 m. This may have implications for diseases of the cardiopulmonary system.Published with support from the Colorado State University Libraries Open Access Research and Scholarship Fund
Radiocephalic and brachiocephalic arteriovenous fistula outcomes in the elderly
BackgroundA recent meta-analysis has suggested that patients aged >65 have worse outcomes with radiocephalic arteriovenous fistulas (RCAVFs) compared with brachiocephalic arteriovenous fistulas (BCAVFs). We hypothesized that outcomes in patients aged ≥80—a rapidly expanding cohort within this elderly group—might be skewing the results, and that age >65 may not be a contraindication to RCAVF formation. This study examined the effect of age group (<65, 65 to 79, ≥80) on functional outcomes (use; primary and secondary functional patency) in RCVAFs and BCAVFs.MethodsWe identified the outcomes of all patients undergoing a first surgical access procedure for a RCAVF or BCVAF between January 1, 2000, and December 31, 2005. We examined the effect of age and other factors including sex, diabetes mellitus, hypertension, late referral (<3 months before dialysis), dialysis before surgical access, preoperative duplex ultrasound imaging, and ethnicity on non-AVF use and primary and secondary functional AVF patency. Logistic regression and Cox proportional hazards regression models were used.ResultsFrom a total of 658 patients, 361 had a RCAVF, and 297 had a BCAVF. Their median age was 68.5 years (interquartile range [IQR], 54.4 to 76.5 years), and 288 (43.8%) were aged <65 years, 274 (41.6%) were 65 to 79, and 96 (14.6%) were ≥80. Age did not influence the site of the first surgical access (P = .874). Only 85.7% of patients actually progressed to hemodialysis, and the RCAVF or BCAVF in 45.7% of those was never used for dialysis. Female sex (hazard ratio [HR], 2.24; 95% confidence interval [CI] 1.387 to 3.643; P = .001) was the only factor associated with an increase risk of RCAVF nonuse, whereas diabetes (HR, 2.095; 95% CI, 1.261 to 3.482; P = .004) was the only factor associated with an increase risk of BCAVF nonuse. The respective primary patency rates at 1 and 2 years for RCAVFs were 46.0% and 27.1% for patients <65, 47.0% and 36.0% for those 65 to 79, and 45.7% and 38.1% for those ≥80. Only female sex (HR, 1.679; 95% CI, 1.261 to 2.236; P = .001) and prior hemodialysis (HR, 1.363; 95% CI, 1.0.29 to 1.804; P = .031) were associated with loss of patency of RCAVFs. The primary functional patency rates for BCAVFs at 1 and 2 years were 39.3% and 31.0% for those <65 years; 53.30% and 37.5% for those 65 to 79, and 46.3% and 42.6% for those ≥80. No factors analyzed were associated with loss of primary functional patency of BCAVFs.ConclusionsAge did not affect usability, primary or secondary patency of either RCAVFs or BCAVFs. Although patient selection is important, even patients ≥80 years who are considered suitable for surgical placement of access should not be denied a RCAVF solely because of age
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