• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1199
  • 243
  • 106
  • 90
  • 90
  • 85
  • 33
  • 15
  • 14
  • 14
  • 13
  • 12
  • 12
  • 10
  • 10
  • Tagged with
  • 2407
  • 2407
  • 450
  • 364
  • 318
  • 295
  • 212
  • 192
  • 178
  • 167
  • 142
  • 127
  • 121
  • 116
  • 112
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Chemical facility preparedness a comprehensive approach

Pennington, Daniel 09 1900 (has links)
CHDS State/Local / Experts agree that the nation's chemical facilities are attractive targets for terrorists. This consensus is due to several conditions. First, there are thousands of facilities scattered across the country that use, manufacture or store large stockpiles of toxic and/or flammable substances. Many sites are clustered together in densely populated areas and are poorly protected. If terrorists cause catastrophic chemical releases or explosions at these key facilities, large numbers of Americans will be put at risk of injury or death. Second, such attacks may also have a devastating impact on the U.S. economy because so many other industries are dependent on a properly functioning chemical sector. Surprisingly in light of these risks, most chemical sites have not implemented sufficient measures to prevent, mitigate, deter, and/or respond to terrorist attacks. Although governmental entities (local, state and federal) and the chemical industry have initiated some safeguards, they only apply to a limited number of chemical facilities. The vast majority is still not adequately prepared for terrorism. This thesis proposes that private and public sectors should partner together to improve the preparedness of the chemical industry for terrorist acts. More specifically, key stakeholders from both sectors need to forge Regional Defense Units (RDUs). Their primary purpose is to effectively reduce the attractiveness of local chemical facilities as targets for terrorists without unduly hampering their operations. To achieve this goal, a mixture of mandates ("sticks") and incentives ("carrots") need to be regionally developed, implemented and sustained by RDUs. Collaborative regional efforts using an appropriately balanced and community-governed "carrot and stick" approach can be the most effective option for the Department of Homeland Security to improve chemical facility preparedness, and thus homeland security. / Lieutenant, Pasadena Police Department
322

Forensic risk assessment : a metareview, novel meta-analysis, and empirical study developing a violence screening tool for schizophrenia

Singh, Jay January 2011 (has links)
Mental health professionals are routinely called upon to assess the violence risk of their patients. An increasingly common method for conducting such assessments is the use of structured risk assessment tools. The aim of this thesis was to investigate the utility of such instruments: to identify and explore current uncertainties concerning their applicability and to design a novel measure that could be used as part of a stepped strategy to risk assessment. Though a number of risk assessment tools have been developed and there is a considerable literature concerning their psychometric properties, uncertainty remains regarding their effective use. In order to identify key contemporary uncertainties, a metareview of the forensic assessment literature was conducted. The metareview found that previous systematic reviews and meta-analyses of the risk assessment literature have come to conflicting conclusions on a number of issues, including the comparative predictive validity of risk assessment tools, the efficacy of actuarial tools versus clinical judgement, and the influence of demographic factors and study design characteristics on predictive accuracy. These uncertainties were then investigated in a comprehensive meta-analysis of nine commonly used risk measures. The meta-analysis concluded that there were significant differences between the predictive validity of the risk assessment tools, with instruments designed for more specific purposes performing better than those designed for more general use. Tools performed best when administered to samples demographically similar to their calibration sample. Actuarial instruments and structured clinical judgement were found to perform comparably. The final study presented in this thesis explored the feasibility of a stepped approach to risk assessment in which individuals at very low risk of future violence are screened out prior to resource-intensive clinically based assessment. High-quality national registers were used to construct a simple tool to identify patients with schizophrenia at very low risk of violent conviction after being discharged from hospital. The tool was found to produce high rates of sensitivity as well as high negative predictive values at 1, 2, and 5 years follow.up. In light of the findings of these three studies, risk assessment procedures and guidelines by mental health services and criminal justice systems may need review.
323

Nurses' Perception of the Use of the Dynamic Appraisal of Situational Aggression (DASA) in an Emergency Psychiatric Setting

Underwood, Stacy, Underwood, Stacy January 2017 (has links)
Background: The use of the Dynamic Appraisal of Situational Aggression (DASA) in acute psychiatric settings to identify aggressive and/or violent patients upon admission. Objective: Determining nurses' perception of the usefulness of the Dynamic Assessment of Situational Aggression (DASA) in a psychiatric emergency room setting. Theoretical Background: Langley, Nolan, Nolan and Provost’s (2009) Model for Improvement, which incorporates Deming’s Plan-Do-Study-Act (PDSA) cycle, was utilized as the theoretical framework to guide this DNP project. Setting: An adult psychiatric emergency room in urban Phoenix, Arizona. Measurement: A six-item survey questionnaire measured on a five-point Likert scale ranging from "Strongly Disagree" (1) to "Strongly Agree" (5) describes and measures nurses' perception on the usefulness of the DASA. An additional question explored the influence of static nursing factors (gender, years of experience, level of education, years at the facility), on nurses' perception of the usefulness of the DASA. Results: Overall, nurses (90%) of the study participants perceived the DASA to be effective in identifying aggressive violent patients and 70% of the participants would like to continue to use the DASA. Static nursing factors showed no difference in nurses' perception of usefulness. Limitations: Further exploration in similar settings such as regular emergency departments and psychiatric emergency and crisis settings are recommended. In this study only nursing perception was explored. Analysis of the validity of the DASA tool in the psychiatric emergency room setting in addition to nursing perceptions would be more beneficial in determining the DASA’s true usefulness. Conclusion: The results of this DNP project demonstrate that nurses at the SAUPC perceive the DASA to be a useful addition to their admission assessment. Overall nursing response was positive and the SAUPC seclusion and restraint committee recommended incorporating the DASA into the triage nursing admission assessment.
324

Predicting HIV Status Using Neural Networks and Demographic Factors

Tim, Taryn Nicole Ho 15 February 2007 (has links)
Student Number : 0006036T - MSc(Eng) project report - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Demographic and medical history information obtained from annual South African antenatal surveys is used to estimate the risk of acquiring HIV. The estimation system consists of a classifier: a neural network trained to perform binary classification, using supervised learning with the survey data. The survey information contains discrete variables such as age, gravidity and parity, as well as the quantitative variables race and location, making up the input to the neural network. HIV status is the output. A multilayer perceptron with a logistic function is trained with a cross entropy error function, providing a probabilistic interpretation of the output. Predictive and classification performance is measured, and the sensitivity and specificity are illustrated on the Receiver Operating Characteristic. An auto-associative neural network is trained on complete datasets, and when presented with partial data, global optimisation methods are used to approximate the missing entries. The effect of the imputed data on the network prediction is investigated.
325

The relationship between modifiable health risk factors and health care costs for individuals who have completed a health risk assessment questionnaire for a South African health insurance scheme

Garbharran, Dinesh Hari Lall 08 March 2012 (has links)
M.Sc., Faculty of Science, University of the Witwatersrand, 2011 / Health care funders are seeking managed health care interventions to contain medical inflation. The purpose of this study is to assess the relationship between three health risk factors (smoking status, physical activity and body mass index (BMI)) and inpatient costs among health risk assessment (HRA) respondents at a South African health insurer. The results could inform the design of wellness programmes by ensuring that appropriate health risk factors are being targeted to reduce inpatient costs. This study utilises a two-part regression model to explore the relationships between the health risk factors and inpatient costs. The combined results of the two-part regression model indicate that increasing levels of physical activity and decreasing levels of BMI are associated with lower likelihoods of hospitalisation and lower magnitudes of inpatient costs for those that had a non-zero claim. The results of this study indicate no association between smoking cessation and lower inpatient costs.
326

Determinants of environmental perceptions of rural inhabitants in Bushbuckridge, South Africa

Mbewe, Philip 10 May 2016 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Resource Conservation Biology (Coursework and Research Report) Johannesburg, February 2016 / Environmental perceptions have been researched in a wide range of communities globally. However, the environmental perceptions of rural people in the developing world, as well as their determinants, remain understudied. Investigating rural inhabitants’ environmental perceptions and what shapes them can produce useful information that could be incorporated into decision-making process that help resolve environmental issues. This study aimed to investigate dominant environmental perceptions and their determinants at individual, household and village levels, with a focus on environmental resource use, resource availability, and resource governance and management, among rural inhabitants of Bushbuckridge region in Mpumalanga Province, South Africa. This study used unanalysed pre-existing data for 300 rural households across five villages, collected via a questionnaire in 2006. Of the twelve local resources considered, fuelwood, edible wild herbs, grass and twigs for brooms, reed mats and wooden carvings were the most widely used resources. Building poles, thatch for roofs, and bushmeat were the least widely used resources. On the frequency of use of consumable resources, most households consumed fuelwood every day while edible wild herbs, wild fruits and edible insects were mostly consumed 1-3 times/week. The majority of user households used traditional medicine and bushmeat less than once a month. The majority of respondents perceived local availability of edible wild herbs, traditional medicine, edible insects, and wild fruits to be adequate. By contrast, less than a third of respondents indicated sufficient local supply of building poles, bushmeat and fuelwood. However, it was dominantly perceived that it is not necessary to get harvesting permits for most resources, except in the case of traditional medicines. The chief was repeatedly perceived to be the ultimate authority in issuing harvesting permits and regulating access to natural resources. Individual and household level characteristics, as well as village resided in, were found to shape a range of individuals’ environmental perceptions with regards to resource availability and resource governance and management, but their influence was not consistent across resource or governance issues. For instance, at the individual level, age significantly shaped individuals perceptions of resource governance and management regarding who controls access to natural resources. The youth and middle aged compared to elderly were less likely to perceive that the chief controls access to resources and were also more likely to perceive that the government controls access to resources than elderly. Household-level characteristics were found to have no influence on perceptions of who controls access to resources. Village resided in shaped perceptions of resource availability, for every resource, and most aspects of resource governance issues. Village resided in had a stronger influence on range of individuals’ environmental perceptions than individual and household level factors. Households which depended highly on natural resources were more likely to perceive shortages of resources and an increase in household resource use, the likelihoods of individuals perceiving community development forum and the community itself regulating access to the natural resources increased. It is clear that environmental perceptions vary within and between communities, and are shaped by the characteristics and circumstances of the individual, their households and the community they live in. Furthermore, the strength of influence of these determinants varies according to the particular resource and environmental governance issue concerned. The understanding and identification of factors that shapes individuals’ environmental perceptions will be helpful for policy makers, as it could establish solutions that are grounded in rural communities’ realities and their environmental perceptions.
327

Prices of Credit Default Swaps and the Term Structure of Credit Risk

Desrosiers, Mary Elizabeth 01 May 2007 (has links)
The objective of this project is to investigate and model the quantitative connection between market prices of credit default swaps and the market perceived probability and timing of default by the underlying borrower. We quantify the credit risk of a borrower in a two-way relationship: calculate the term structure of default probabilities from the market prices of traded CDSs and calculate prices of CDSs from the probability distribution of the time-to-default.
328

Threats associated with build, operate and transfer (B.O.T) infrastructure projects in Southern Africa and the impact it has on the risk profile.

Moloigaswe, Shimah. 15 January 2014 (has links)
The rapid economic growth in many developing countries results in a high demand for infrastructure and governments find that they are unable to fund the vital infrastructure or to maintain the existing ones (Gupta and Sravat, 1998). To remedy this they are increasingly opting for an alternative source of funding through the large international companies which have considerable credit standing for concession contracts such as Build Operate and Transfer (BOT) since those companies have a much larger capacity to fund the large scale projects than the recipient country. The objective of this research project is to provide a brief review of the South African experience with the utilisation of the BOT approach for infrastructure developments, examining the risks and the measures used to mitigate them. This is so as to draw lessons for policy makers on how to improve the use of this strategic instrument for infrastructure provision. The emphasis will be on overall risks associated with the scheme as well as the mitigating factors in light of the current social, political and economic context of the country and the region. Data was collected using the Delphi survey method and the study targeted individuals who were knowledgeable and experienced with the issues under investigation and from different sectors involved with execution of BOT infrastructure development projects in South Africa. These included contractors, lenders, operators as well as some from the host government. The questionnaire was designed to identify the perceptions of the individuals regarding risk management in BOT projects as well as identify significant risk associated with the scheme. The 10 most critical risks were ranked based on the ratings of the respondents in the final phase of the Delphi survey. The risk that was rated the most critical turned out to be ‘Political instability in the host country’. This is defined as the danger of political or financial instability in the host country caused by events such as insurrections, strikes, creeping expropriation and outright nationalization.
329

Desenvolvimento de epiderme equivalente sobre membrana do tipo transwell e membrana biopolimérica / Development of an epidermal equivalent model on a transwell and on a biopolymer scaffold

Catarino, Carolina Motter 11 May 2015 (has links)
Atualmente existe uma forte tendência mundial para o desenvolvimento de testes in vitro que supram o uso de animais em ensaios de avaliação de segurança. Em 1986 a Diretiva Europeia 86/609/EEC induziu a discussão mundial de redução de testes em animais e a 7ª emenda desta Diretiva, publicada em 2004, determinou a transferência dos ensaios para a avaliação de risco para sistema in vitro. Diferentes abordagens foram desenvolvidas para suprir essa necessidade como, por exemplo, a geração de equivalentes de epiderme, que foi considerada a mais promissora e extensamente investigada. Dois modelos de equivalentes de epiderme (EpiDermTM-MATTEK e EPISKINTM LORÉAL) comercialmente disponíveis foram validados pelo ECVAM (Centro Europeu para a Validação de Métodos Alternativos) e outros modelos de epiderme reconstruída estão sendo desenvolvidos em diferentes laboratórios de pesquisa do mundo. Esses dois modelos são recomendados no Guia 431 (Organização para cooperação e desenvolvimento econômico - OECD) que avalia in vitro a corrosão da pele. No Brasil esta prática ainda é inexistente, porém deverá ser implementada rapidamente para que atenda aos conceitos humanitários internacionais. Sendo assim, este projeto teve como objetivo criar, dentro dos princípios do Guia 431, um equivalente de epiderme e posterior otimização deste processo através da incorporação de uma membrana biopolimérica (PET e colágeno I) como suporte celular. O modelo de epiderme humana reconstruída consiste de um tecido epidérmico diferenciado tridimensionalmente a partir de queratinócitos humanos normais cultivados em um meio quimicamente definido na interface ar-líquido. A validação deste modelo para ensaios de avaliação do potencial corrosivo de substâncias foi realizada seguindo os princípios do Guia 431 da OECD, sendo que quatro substâncias da lista indicada pelo Guia foram testadas: duas corrosivas (Ácido Lático e Ácido Octanóico) e duas não corrosivas (2-bromo Etilbenzeno e Benzilacetona), assim como controles positivo (Acido acético) e negativo (NaCl 0,9%). Os resultados de viabilidade celular após 3 minutos e 1 hora de exposição às substâncias teste demostraram que o nosso modelo permite distinguir as substâncias entre corrosivas e não corrosivas, no entanto não permite a subcategorização das corrosivas em 1A ou 1B/C. Assim, nós demonstramos o potencial do nosso modelo como um método de teste relevante e confiável que pode ser usado para pesquisa e investigação de risco químico. Visando a otimização do modelo, testamos a incorporação de uma membrana biopolimérica eletrofiada de PET e colágeno tipo I como suporte para crescimento celular em substituição ao transwell. A análise histológica das membranas demonstrou que as mesmas são biocompativeis, permitindo adequada adesão e proliferação dos queratinócitos e dos fibroblastos, no entanto, não se observou uma diferenciação adequada com a formação de uma epiderme semelhante à humana (estratos basal, espinhoso, granuloso e córneo). Além disso, a falta de uniformidade e reprodutibilidade nos resultados indicam que é necessário uma otimização dos processos de fabricação das membranas e geração do equivalente epidérmico. Em perspectiva, este equivalente epidérmico poderá ser utilizado para pesquisa e avaliação de risco de fármacos, medicamentos, cosméticos, praguicidas, etc., contribuindo para a geração de métodos alternativos aos testes em animais e inserindo o Brasil na tendência internacional do desenvolvimento de testes para avaliação do risco. / Currently there is a strong global trend towards the development of in vitro tests that fulfill the use of animals in safety evaluation tests. In 1986, the European Directive 86/609/EEC led to the discussion of global reduction of animal testing and the 7th amendment of this Policy, published in 2004, ordered the transfer of the tests for risk assessment for in vitro system. Different approaches have been taking into account to achieve this goal, for example, the development of epidermal equivalents models, which have been considered the most promising and widely studied model. ECVAM (European Centre for the Validation of Alternative Methods) has validated two models of reconstructed epidermis (EpiDermTM - Mattek and EPISKINTM - L\'Oréal) that are commercially available and other models are being developed in different research laboratories in the world. These two models are recommended in Guide 431 (Organisation for Economic Cooperation and Development - OECD) for in vitro evaluation of skin corrosion. In Brazil, this practice is still lacking, but should be implemented quickly so that meets international humanitarian concepts. Therefore, this project aimed the creation, within the principles of Guide 431, of an epidermal equivalent and the optimization of this process through the incorporation of a biopolymer membrane (PET and collagen I) as cellular support. The reconstructed human epidermis (RHE) consists of a differentiated three-dimensional epidermal tissue reconstructed from normal human keratinocytes in a chemically defined medium and air liquid interface growth. The validation of this model for the assessment of skin corrosion potential of substances was performed following the principles of the OECD Guide 431, hereupon four substances from the list indicated by the Guide were tested: two corrosive (lactic acid and octanoic acid) and two non-corrosive (2-phenylethyl bromide and benzylacetone) and positive (acetic acid) and negative (NaCl 0.9%) controls. The cell viability results after 3 minutes and 1 hour of exposure to the test substances indicates that our model is capable of distinguishing the substances among corrosive and non-corrosive. Although they do not, allow the sub-categorization of corrosive in 1A or 1B/C. Thus, we have demonstrated that our model is a potentially relevant and a reliable test method that could be used in research and specifically for the investigation of chemical hazard. To optimize the model, we tested the incorporation of a biopolymer membrane composed of PET and type I collagen as support for cell growth, as a replacement of the transwell. Histological examination of membranes has shown that they are biocompatible, enabling adequate adhesion and proliferation of keratinocytes and fibroblasts. However, there was no adequate differentiation with the formation of a similar human epidermis (stratum basale, spinosum, granulosum and corneum). Moreover, the lack of uniformity and reproducibility of the results indicates that it is still necessary to optimize the membranes production process and the generation of the epidermal equivalent using the membranes as support. In perspective, the developed epidermal equivalent may be used for research and risk assessment of pharmaceuticals, medicines, cosmetics, chemicals, pesticides, among others. This directly contributes to the development of alternative methods able to substitute animal testing in Brazil and follows the international trend of development tests for risk assessment.
330

Avaliação do risco de intoxicação por vapores de mercúrio / Assessment of the risk of mercury poisoning

Colacioppo, Sergio 20 October 1976 (has links)
O mercúrio, devido a suas propriedades físicas e químicas peculiares, é utilizado em grande número de atividades humanas, representando assim uma parcela significativa na economia de diversos paises. Por outro lado, o mercúrio possue propriedades tóxicas e que associadas à periculosidade dos seus vapores ou a dos resíduos industriais, representa considerável risco à saúde do trabalhador e dos moradores das adjacencias de indústrias que lidam com este metal. O mercúrio pode apresentar-se no meio ambiente sob várias formas, sendo que na forma metálica é que representa maior problema de saúde ocupacional, devido a formação de vapores inodoros e incolores - que possuem grande facilidade de penetração e absorção por via respiratória. Assim o mercúrio na forma de vapor mereceu maior atenção neste estudo. Nao se têm até o presente completamente esclarecido o mecanismo da ação tóxica do mercúrio no organismo humano, havendo ainda algumas contradições e divergências na interpretação de resultados laboratoriais de pesquisa do metal em urina, sangue, cabelos e outros meios biológicos, ou ainda das determinações de alterações metabólicas produzidas pela ação do mercúrio no organismo humano. Uma avaliação do risco de intoxicação profissional por vapores de mercúrio, representada pela determinação dos níveis de vapor de mercúrio num ambiente de trabalho, além da avaliação do risco em si, auxilia o médico no diagnóstico da intoxicação, bem como\'o engenheiro a testar a eficiência das medidas preventivas existentes. Ao planejar uma avaliação ambiental, de vapores de mercúrio o higienista industrial depara-se na bibliografia especializada, com processos diversos de captação e análise e sem indicação da eficiência na grande maioria. Foi então realizado um estudo comparativo entre os processos, mais viáveis, dois deles utilizando absorção em solução ácida de permanganato de potássio e solução de iôdo e outros dois utilizando adsorção com carvão ativo e com hopcalita. Para efeito de realização do estudo acima referido fez-se necessária a construção de equipamento que fornecesse uma atmosfera padrão de vapores de mercúrio - proposto e descrito no presente trabalho - foi fixado igualmente o processo analítico, tendo sido escolhido o de absorção atômica sem chama devido à sua alta sensibilidade, acuidade e precisão. As concentrações produzidas foram ligeiramente superiores à preconizada pela ACGIH como limite de tolerância e o processo que maior confiabilidade apresentou foi o que utiliza solução ácida de permanganato de potássio sendo o de maior acuidade e precisão. / Due to its peculiar physical and chemical properties, mercury is applied in a great nurnber of human activities and represents a significative portion of the economy of several countries. On the other hand mercury has some toxic properties that, when associated to its hazardous vapours or to industrial wastes becomes a considerable risk to the health of workers from industries that deal with it or the neighbouhood dwellers. Mercury can be found under several forms: the metalic one is the main problem to occupational health, specially when there is occurrence of mercury vapour - inodorous and uncoulored - easily absorbed by the respiratory tract. Thus, mercury vapour deserved our attention in this paper. The toxic action of mercury in human beings is not completely known yet for there are still some contradictions and divergencies about the interpretation of laboratorial findings of the metal in urine blood, hair and other biological samples as well as about the establishment of a threshould limit for metabolic alterations caused by the mercury in human organism. An evaluation of professional intoxication risk due to mercury vapour by measuring its level in a work area will help the physician to diagnosticate the intoxication and the engineer to test the eficacy of the existing preventive measures. When planning an environmental evaluation of the mercury vapour, the industrial hygienist can find different processes of collection and analysis in the specialized bibliography, most of them without any evidence of its effectiveness. A comparative study was then carried out on the most useful processes, two of them applying absortion in acid solution potassium permanganate and iodine solution, and the two others making use of adsortion with active charcoal and hopcalite. To fulfil the above mentioned study, it was necessary to buil up an equipment that could provide a standard atmosphere of mercury vapour (proposed and described here). The analitic process of flameless atomic absortion was chosen due to its high sensibility ando accuracy. The concentrations produced were slightly superior to the ones professed by the ACGIH as the threshol limit, and it was found that the most reliable process was the acid solution of pottassium permanganate, for its accuracy and eficiency.

Page generated in 0.0671 seconds