858 resultados para [JEL:C5] Mathematical and Quantitative Methods - Econometric Modeling


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A novel solution to the long standing issue of chip entanglement and breakage in metal cutting is presented in this dissertation. Through this work, an attempt is made to achieve universal chip control in machining by using chip guidance and subsequent breakage by backward bending (tensile loading of the chip's rough top surface) to effectively control long continuous chips into small segments. One big limitation of using chip breaker geometries in disposable carbide inserts is that the application range is limited to a narrow band depending on cutting conditions. Even within a recommended operating range, chip breakers do not function effectively as designed due to the inherent variations of the cutting process. Moreover, for a particular process, matching the chip breaker geometry with the right cutting conditions to achieve effective chip control is a very iterative process. The existence of a large variety of proprietary chip breaker designs further exacerbates the problem of easily implementing a robust and comprehensive chip control technique. To address the need for a robust and universal chip control technique, a new method is proposed in this work. By using a single tool top form geometry coupled with a tooling system for inducing chip breaking by backward bending, the proposed method achieves comprehensive chip control over a wide range of cutting conditions. A geometry based model is developed to predict a variable edge inclination angle that guides the chip flow to a predetermined target location. Chip kinematics for the new tool geometry is examined via photographic evidence from experimental cutting trials. Both qualitative and quantitative methods are used to characterize the chip kinematics. Results from the chip characterization studies indicate that the chip flow and final form show a remarkable consistency across multiple levels of workpiece and tool configurations as well as cutting conditions. A new tooling system is then designed to comprehensively break the chip by backward bending. Test results with the new tooling system prove that by utilizing the chip guidance and backward bending mechanism, long continuous chips can be more consistently broken into smaller segments that are generally deemed acceptable or good chips. It is found that the proposed tool can be applied effectively over a wider range of cutting conditions than present chip breakers thus taking possibly the first step towards achieving universal chip control in machining.

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BACKGROUND: Early detection of colorectal cancer through timely follow-up of positive Fecal Occult Blood Tests (FOBTs) remains a challenge. In our previous work, we found 40% of positive FOBT results eligible for colonoscopy had no documented response by a treating clinician at two weeks despite procedures for electronic result notification. We determined if technical and/or workflow-related aspects of automated communication in the electronic health record could lead to the lack of response. METHODS: Using both qualitative and quantitative methods, we evaluated positive FOBT communication in the electronic health record of a large, urban facility between May 2008 and March 2009. We identified the source of test result communication breakdown, and developed an intervention to fix the problem. Explicit medical record reviews measured timely follow-up (defined as response within 30 days of positive FOBT) pre- and post-intervention. RESULTS: Data from 11 interviews and tracking information from 490 FOBT alerts revealed that the software intended to alert primary care practitioners (PCPs) of positive FOBT results was not configured correctly and over a third of positive FOBTs were not transmitted to PCPs. Upon correction of the technical problem, lack of timely follow-up decreased immediately from 29.9% to 5.4% (p<0.01) and was sustained at month 4 following the intervention. CONCLUSION: Electronic communication of positive FOBT results should be monitored to avoid limiting colorectal cancer screening benefits. Robust quality assurance and oversight systems are needed to achieve this. Our methods may be useful for others seeking to improve follow-up of FOBTs in their systems.

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This exploratory study assesses the utility of substance abuse treatment as a strategy for preventing human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs). Data analyzed in this study were collected in San Antonio, TX, 1989 through 1995 using both qualitative and quantitative methods. Qualitative data included ethnographic interviews with 234 active IDUs; quantitative data included baseline risk assessments and HIV screening plus interviews follow-up interviews administered approximately six months later to 823 IDUs participating in a Federally-funded AIDS community outreach demonstration project.^ Findings that have particularly important implications for substance abuse treatment as an HIV prevention strategy for IDUs are listed below. (1) IDUs who wanted treatment were significantly more likely to be daily heroin users. (2) IDUs who want treatment were significantly more likely to have been to treatment previously. (3) IDUs who wanted treatment at baseline reported significantly higher levels of HIV risk than IDUs who did not want treatment. (4) IDUs who went to treatment between their baseline and follow-up interviews reported significantly higher levels of HIV risk at baseline than IDUs who did not go to treatment. (5) IDUs who went to treatment between their baseline and follow-up interviews reported significantly greater decreases in injection-related HIV risk behaviors. (6) IDUs who went to treatment reported significantly greater decreases in sexual HIV risk behaviors than IDUs who did not go to treatment.^ This study also noted a number of factors that may limit the effectiveness of substance abuse treatment in reducing HIV risk among IDUs. Findings suggest that the impact of methadone maintenance on HIV risk behaviors among opioid dependent IDUs may be limited by the negative manner in which it is perceived by IDUs as well as other elements of society. One consequence of the negative perception of methadone maintenance held by many elements of society may be an unwillingness to provide public funding for an adequate number of methadone maintenance slots. Thus many IDUs who would be willing to enter methadone maintenance are unable to enter it and many IDUs who do enter it are forced to drop out prematurely. ^

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An increasing number of clubs experience difficulties in recruiting and retaining sufficient numbers of volunteers to manage and staff their clubs (Lamprecht, Fischer, & Stamm, 2012). In order to facilitate volunteer recruitment, sport clubs need a specific strategy to recruit and retain volunteers for both formal positions and ad hoc tasks. Therefore, the intervention “More Volunteers in Football Clubs” was designed and its impact was evaluated in detail. The question this evaluation research wants to address is: Can football clubs recruit and retain volunteers successfully by implementing the intervention “More Volunteers in Football Clubs”? The designed intervention is based on the different expectations and needs of volunteers, as well as non-profit human resource management and organisational development management, with a strong emphasis on club-specific counseling and support. Task forces of the twelve participating football clubs attended four workshops in which they received tailor made counseling to reach the desired number of volunteers. The intervention has been implemented and its effectiveness tested in cooperation with the Swiss Football Federation with twelve Swiss football clubs following a pretest, intervention, posttest design Data have been gathered and analysed using a combination of qualitative and quantitative methods. Outcome measurements are: volunteer rate, number of recruited volunteers, number of filled volunteer positions and volunteer satisfaction. Four months after the intervention all clubs that completed the proposed intervention were successful in recruiting the desired number of volunteers. Further, all participating clubs found the intervention helpful and would recommend other clubs to participate as well. With the development of this practical intervention a solution for football clubs is provided to overcome the difficulties in recruiting and retaining sufficient numbers of volunteers. Lamprecht, M., Fischer, A., & Stamm, H.-P. (2012). Sportvereine in der Schweiz. Strukturen, Leistungen, Herausforderungen. Zürich, Switzerland: Seismo.

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Introduction Gene expression is an important process whereby the genotype controls an individual cell’s phenotype. However, even genetically identical cells display a variety of phenotypes, which may be attributed to differences in their environment. Yet, even after controlling for these two factors, individual phenotypes still diverge due to noisy gene expression. Synthetic gene expression systems allow investigators to isolate, control, and measure the effects of noise on cell phenotypes. I used mathematical and computational methods to design, study, and predict the behavior of synthetic gene expression systems in S. cerevisiae, which were affected by noise. Methods I created probabilistic biochemical reaction models from known behaviors of the tetR and rtTA genes, gene products, and their gene architectures. I then simplified these models to account for essential behaviors of gene expression systems. Finally, I used these models to predict behaviors of modified gene expression systems, which were experimentally verified. Results Cell growth, which is often ignored when formulating chemical kinetics models, was essential for understanding gene expression behavior. Models incorporating growth effects were used to explain unexpected reductions in gene expression noise, design a set of gene expression systems with “linear” dose-responses, and quantify the speed with which cells explored their fitness landscapes due to noisy gene expression. Conclusions Models incorporating noisy gene expression and cell division were necessary to design, understand, and predict the behaviors of synthetic gene expression systems. The methods and models developed here will allow investigators to more efficiently design new gene expression systems, and infer gene expression properties of TetR based systems.

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The distribution of stratigraphically important calcareous nannofossils and planktonic foraminifera has been investigated in the Pliocene-Pleistocene sequences of ODP Sites 652, 653, and 654 (Tyrrhenian Sea-western Mediterranean). Semiquantitative and quantitative methods have been used, and an optimum relative sequence of bioevents based on the calcareous plankton groups has been established. About 30 bioevents in an interval of 5.0 m.y. are considered widely traceable in the area and reasonably synchronous. On the basis of those events, a correlation among the three investigated sequences is presented.

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Regarding different programmes belonging to the public sphere, it is essential to have proper tools able to quickly provide accurate data related to impacts generated by its projects. This aspect, along with the actual use of this data is essential for proper planning. This communication presents the system designed for project-based evaluation of the employment programs in the Community of Madrid. This system aims to provide fast and reliable information by relying on a combination of qualitative and quantitative methods from existing information and structures. Another contribution of the designed system is the implementation of the Empowerment Evaluation as a tool to encourage the incorporation of evaluation results to the planning processes in a systematic way.

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Introdução: Os impactos das alterações climáticas são e serão sentidos localmente, e irão variar de lugar para lugar. Nas regiões mais sensíveis à variabilidade climática, onde outros fatores e restrições afetam o desenvolvimento, a mudança climática terá um impacto significativamente maior. Uma da preocupações mais recentes da comunidade científica é que esses impactos negativos das alterações climáticas sobre a sociedade, saúde e o meio ambiente possa vir a restringir quaisquer ganhos realizados até o momento na melhora da qualidade de vida das populações, e em especial na região nordeste do Brasil. Neste contexto, as mudanças climáticas, bem como a variabilidade climática natural com seus extremos, podem vir a acentuar uma vulnerabilidade social já existente, fazendo com que a qualidade de vida das populações mais vulneráveis seja especialmente e desproporcionalmente afetada. Objetivo: Analisar como os impactos das políticas públicas de transferência de renda em especial o Programa Bolsa Família e a Aposentadoria Rural influênciam a qualidade de vida frente à variabilidade e mudanças climáticas de famílias pobres no nordeste brasileiro. Métodos: Fez-se uso de métodos qualitativos e quantitativos de coleta e análise de dados sobre as diferentes formas de pobreza e vulnerabilidade e a relação com a capacidade de adaptação à seca, e como isso afeta a percepção de qualidade de vida em famílias pobres rurais e urbanas em dois municípios do estado do Ceará (Parambu e Boa Viagem) sobre o estresse da seca. Realizou-se 221 entrevistas domiciliares (141 na zona rural e 80 na zona urbana). Complementarmente foram coletados dados qualitativos obtidos através de entrevistas semiestruturadas com informantes-chaves (gestores municipais e estaduais, chefes religiosos, presidentes de associações rurais e agentes de saúde). Os dados foram codificados e analisados com o auxílio do N-Vivo e do SPSS. Resultados: Os resultados foram separados e apresentados em formato de três manuscritos. Em geral, os resultados mostram que apesar dos programas de transferência de renda agirem positivamente na 16 melhora da qualidade de vida da famílias beneficiadas, durante o evento de seca as famílias não conseguem superar os fatores que as tornam vulneráveis, o que pode afetar sua percepção de bem-estar subjetivo. Ao mesmo tempo, devido às limitações e deficiências das intervenções políticas de intervenção de seca, as relações de dependência e clientelismo, característica da região, continuam a perpetuar. Conclusão: Os ganhos materiais na qualidade de vida, promovidos pelos programas sociais, como o Bolsa Família e a pensão rural, apesar de serem necessários, não são suficientes para promover uma transformação na vida dessas famílias

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Different factors have been shown to influence the development of models of advanced nursing practice (ANP) in primary-care settings. Although ANP is being developed in hospitals in Hong Kong, China, it remains undeveloped in primary care and little is known about the factors determining the development of such a model. The aims of the present study were to investigate the contribution of different models of nursing practice to the care provided in primary-care settings in Hong Kong, and to examine the determinants influencing the development of a model of ANP in such settings. A multiple case study design was selected using both qualitative and quantitative methods of data collection. Sampling methods reflected the population groups and stage of the case study. Sampling included a total population of 41 nurses from whom a secondary volunteer sample was drawn for face-to-face interviews. In each case study, a convenience sample of 70 patients were recruited, from whom 10 were selected purposively for a semi-structured telephone interview. An opportunistic sample of healthcare professionals was also selected. The within-case and cross-case analysis demonstrated four major determinants influencing the development of ANP: (1) current models of nursing practice; (2) the use of skills mix; (3) the perceived contribution of ANP to patient care; and (4) patients' expectations of care. The level of autonomy of individual nurses was considered particularly important. These determinants were used to develop a model of ANP for a primary-care setting. In conclusion, although the findings highlight the complexity determining the development and implementation of ANP in primary care, the proposed model suggests that definitions of advanced practice are appropriate to a range of practice models and cultural settings. However, the findings highlight the importance of assessing the effectiveness of such models in terms of cost and long-term patient outcomes.

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We would like to reply to the comments made by Paparazzo on our recent paper [1] on theeffect of curve fitting parameters on quantitative analysis of Fe0.94O and Fe2O3 using XPS”. There have been many studies on the characterisation of the properties of iron oxide surfaces. The main purpose of writing the paper was to demonstrate the extent to which the selection of input parameters for curve fitting can affect the results of the quantitative analysis, and to use this analysis to develop more consistent, reproducible and quantitative methods of analysis of these data.

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A gestão de pessoas é um elemento estratégico nas organizações. Dentre as estratégias que podem ser adotadas pela gestão de pessoas, o monitoramento do clima organizacional vem sendo foco nas organizações. No mundo competitivo, as incubadoras de empresas surgem, com o objetivo de proporcionar aos novos empreendimentos, meios para que tenham condições de expandir, auxiliando no desenvolvimento econômico local e regional. O presente estudo objetivou analisar o clima organizacional de três empresas do projeto incubadora de uma cidade do interior do estado de São Paulo e, verificar os impactos que o clima presente está causando nestes empreendimentos. O critério utilizado para a seleção das empresas foi o de graduação, isto é, foram escolhidas empresas com mais tempo de incubadora e que estarão prontas para deixar o projeto no final do ano de 2014. Este estudo valeu-se de métodos qualitativos e quantitativos para poder efetuar o processo metodológico e construir a análise final da pesquisa. Como método quantitativo foi utilizada uma Escala de Clima Organizacional construída e validada por Martins et al. (2004) e como método qualitativo foi realizada uma entrevista com funcionários e gestores das empresas estudadas, com o objetivo de coletar informações para auxiliar no estudo, proporcionar melhor compreensão do ambiente de trabalho e verificar quais os principais impactos causados pelo clima presente. Percebeu-se que, as empresas estudadas, apresentam sérios problemas em seu ambiente de trabalho e, por sua vez, este clima organizacional vem impactando em outras variáveis como, nível de estresse, rotatividade de profissionais, desempenho profissional e na lucratividade destas organizações.

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Este estudo tem como objetivo propor uma análise do modo como se constrói a representação da imagem eleitoral de João Goulart, sob a ótica da propaganda política no cinema brasileiro no período pós-ditadura. Para a realização desse objetivo contamos com o longa-metragem de Silvio Tendler de 1984, intitulado Jango. Cremos que este estudo se justifica por contribuir para identificar, compreender e mapear o imaginário da sociedade brasileira sobre João Goulart. Para o desenvolvimento do tema foram analisadas teorias de marketing político, propaganda ideológica e persuasão. A pesquisa foi norteada pelo método qualitativo e aplicadas as técnicas de pesquisa histórica e estudo de caso. Concluímos que o Filme de Silvio Tendler reconstruiu a imagem de João Goulart ressaltando seu papel na luta pelas reformas de base. A mistificação de Jango foi exposta no documentário expositivo.

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This paper presents a framework based upon a relationship between environmental benefits and the investments and costs needed to implement and run company operations. As the results of environmental management become more evident it is proposed that the benefits rather than the environmental impacts are measured in the analysis of environmental performance. Four categories, or stages, are defined in this paper:creative-green”, “expensive-green”, “inefficient-green or beginner”, and finally, thecomplacent” stage. The paper describes the characteristics of each category and provides examples of indicators that could be used to measure environmental benefits. Qualitative and quantitative methods are necessary to classify companies according to the framework. It is believed that this paper can assist companies and public organisations to assess operations and projects considering their level of sustainability. The proposed framework can impact FDI and environmental policies in the public arena, and foster innovation on environmental practices within the private sector.