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Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients

CARVALHO, Vitor Oliveira; GUIMARÃES, Guilherme Veiga; CIOLAC, Emmanuel Gomes; BOCCHI, Edimar Alcides
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.32%
BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age...

Entre discursos e retóricas: um estudo sobre o reconhecimento e as estratégias de enfrentamento do fracasso escolar em um município da região metropolitana de São Paulo; Between Discourses and Rhetorics: a study on the recognition of and strategies do deal with, school failure in a municipality of the metropolitan area of São Paulo

Cores, Luciano Nunes Sanchez
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 13/05/2010 PT
Relevância na Pesquisa
36.32%
Este trabalho aborda a questão do fracasso escolar, que permanece na pauta de discussões das Políticas Públicas em Educação e é privilegiado pela pesquisa educacional desde a década de 1980. No contexto atual, o fenômeno da não-aprendizagem dos alunos advindos de classes mais pauperizadas adquiriu um caráter público e proporções inaceitáveis, exigindo ações das políticas públicas que se dirijam para seu enfrentamento efetivo. Este estudo parte, assim, da necessidade de se compreender as formas de reconhecimento e as decorrentes políticas de enfrentamento desse fenômeno na esfera dos sistemas públicos e municipais de ensino. Elege como objeto de estudo as formas de reconhecimento do fracasso escolar e as propostas de seu enfrentamento enunciadas pelos supervisores de ensino e nos documentos produzidos no âmbito da Secretaria Municipal de Educação (SME) de uma cidade da região metropolitana de São Paulo. Além da revisão bibliográfica sobre o tema, realizou-se uma pesquisa empirica, com inspirações na perspectiva etnográfica, cujo trabalho de campo baseou-se em observações participantes e entrevistas informais junto ao setor de supervisão escolar desta Secretaria de Educação, indicado como o responsável pela elaboração e implementação das propostas de melhoria da qualidade do ensino municipal. O estudo também contemplou a análise de documentos oficiais emitidos no âmbito desta Secretaria (Planos Muncipais de Educação...

Resiliência e insucesso empresarial: um estudo exploratório sobre o comportamento resiliente e os estilos de enfrentamento do empreendedor em situações de insucesso empresarial, especificamente em casos de descontinuidade do negócio; Resilience and Business Failure - An exploratory study about the entrepreneurs resilient behavior and coping styles in failure situations, more specifically in cases of business discontinuance

Minello, Italo Fernando
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/05/2010 PT
Relevância na Pesquisa
36.32%
A velocidade das transformações econômicas e tecnológicas no ambiente social e no mundo dos negócios exige do empreendedor capacidades cada vez mais adaptativas para que consiga manter a competitividade de seu negócio. O sucesso ou o fracasso empresarial estão condicionados à habilidade deste profissional em superar as adversidades que caracterizam o contexto dos negócios. A diversidade de enfoques teóricos sobre o sucesso traz diferentes perspectivas sobre a sobrevivência das empresas diante da realidade concorrencial do meio empresarial. Por outro lado, no que se refere ao insucesso ou fracasso empresarial, percebe-se uma carência de estudos sobre o assunto. No momento em que se relaciona o comportamento do empreendedor diante desse insucesso, suas características comportamentais, seus estilos de enfrentamento, sua capacidade de superar a adversidade do fracasso, maior ainda é a carência de pesquisas sobre o tema. Essa capacidade de superação evidencia o grau de resiliência do empreendedor diante do insucesso e está relacionada aos estilos de enfrentamento que o empreendedor adota. Em função disso, o presente estudo tem como objetivo analisar o comportamento resiliente e os estilos de enfrentamento dos empreendedores em situações de insucesso empresarial...

Efeito do treinamento físico no controle mecanorreflexo e metaborreflexo da atividade  nervosa simpática muscular em pacientes com insuficiência cardíaca; Effects of exercise training on mechanoreflex and metaboreflex control of muscle sympathetic nerve activity in heart failure patients

Corrêa, Lígia de Moraes Antunes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/06/2013 PT
Relevância na Pesquisa
36.34%
Introdução. A hiperativação nervosa simpática é característica marcante da insuficiência cardíaca. Estudos apontam alterações no controle ergorreflexo muscular (mecano e metaborreflexo) como mecanismos potenciais para explicar esta modificação autonômica. Os mecanorreceptores (fibras do grupo III), que são ativadas pelo aumento no tônus muscular e modulados por metabólitos da via das ciclooxigenases, encontram-se hipersensibilizadas na insuficiência cardíaca. Ao contrário, a sensibilidade dos metaborreceptores (fibras do grupo IV), que são ativados pelo acúmulo de metabólitos durante as contrações musculares e modulados pelos receptores TRPV1 e CB1, encontra-se diminuída na insuficiência cardíaca. Por outro lado, o treinamento físico tem se mostrado uma importante ferramenta no tratamento da insuficiência cardíaca. Ele reduz os níveis de atividade nervosa simpática muscular (ANSM) no repouso e durante o exercício em pacientes portadores desta síndrome. Dessa forma, neste estudo, nós testamos a hipótese de que o treinamento físico melhoraria o controle mecano e metaborreflexo da ANSM em pacientes com insuficiência cardíaca, e se essa melhora está associada às alterações na via das ciclooxigenases e na expressão dos receptores TRPV1 e CB1...

Angiotensina II e treinamento físico na insuficiência cardíaca: implicações para a miopatia esquelética; Angiotensin II and exercise training in Heart Failure: implications to skeletal muscle myopathy

Gomes-Santos, Igor Lucas
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/01/2014 PT
Relevância na Pesquisa
36.38%
INTRODUÇÃO: Capítulo 1. A Insuficiência Cardíaca (IC) é acompanhada de uma hiperativação simpática e do sistema renina-angiotensina (SRA). As ações deletérias do SRA são atribuídas à Angiotensina II (AngII), mas a Angiotensina-(1- 7) (Ang-(1-7)), um metabólito da AngII, demonstra efeitos cardiovasculares benéficos, contrários aos da AngII. O conceito tradicional é de que as concentrações sistêmicas mediam as respostas do SRA, mas evidências emergem acerca da importância funcional do SRA local. Nesse estudo, estudou-se o SRA circulante e muscular esquelético na IC, testando-se a hipótese de que as alterações seriam diferentes nesses dois territórios, e que o treinamento físico corrigiria essas alterações. Capítulo 2. A IC é uma síndrome sistêmica, onde fatores neuroendócrinos, como a AngII, podem levar a alterações periféricas. Na musculatura esquelética, a hiperatividade do sistema ubiquitina-proteassoma (SUP) é um dos elementos que compõem um quadro de miopatia, aumentando o catabolismo muscular em direção à atrofia, e contribuindo com o agravamento da síndrome. O treinamento físico normaliza o SUP e reduz as concentrações plasmáticas de AngII na IC. Dessa forma, testamos a hipótese de que a redução do SUP mediada pelo treinamento físico na IC depende da queda das concentrações plasmáticas de AngII. MÉTODOS: Capítulo 1. Ratos Wistar...

Otimização estrutural sob incertezas considerando consequências de falha; Structural optimization under uncertainties considering consequences of failure

Pedrosa, Thaís Gomes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/03/2015 PT
Relevância na Pesquisa
36.34%
Enfrentar situações de falha é o principal desafio do engenheiro estrutural. Parece paradoxal, mas a fim de obter um projeto bem sucedido, o engenheiro estrutural deve estudar e examinar todos os possíveis modos de falha de uma estrutura. Na otimização estrutural não é diferente. Assim, na otimização estrutural deve-se considerar os custos esperados de falha. No projeto de engenharia estrutural, economia e segurança são aparentemente objetivos conflitantes. No entanto, quando custos esperados de falha são considerados, nota-se que investimentos em segurança são necessários a fim de não arcar com os custos esperados de falha. O ponto ideal de compromisso pode ser encontrado por uma otimização de risco, onde a função objetivo inclui todos os custos ao longo do ciclo de vida da estrutura: construção, operação, manutenção inspeção, descarte e as consequências de falha esperadas. Este último é um remanescente que não pode ser desconsiderado dos modos de falha contra os quais a estrutura precisa ser projetada. Esta dissertação aborda a otimização de sistemas estruturais simples, considerando o equilíbrio entre modos de falha concorrentes, tais como escoamento (esmagamento), flambagem e snap-through. O estudo mostra como os diferentes modos de falha...

Marcadores clínicos e inflamatórios preditores de fracasso terapêutico em pneumonia adquirida na comunidade; Markers of treatment failure in community-acquired pneumonia

Cavalcanti, Manuela Araújo de Nóbrega
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
36.32%
Racional: Aproximadamente um de cada cinco pacientes hospitalizados por pneumonia adquirida na comunidade (PAC) apresenta uma resposta clínica inadequada, sendo a mortalidade nestes pacientes de 40%. Os objetivos do estudo foram: determinar a incidência e as variáveis de associação independente com fracasso terapêutico da PAC, e os fatores prognósticos da PAC tratada em ambiente hospitalar. Métodos: Estudo de coorte, prospectivo, multicêntrico, com 425 pacientes hospitalizados por PAC. Os pacientes foram acompanhados de forma sistemática para identificação do fracasso terapêutico e seguidos até a alta hospitalar. Resultados: A incidência de fracasso terapêutico foi de 14,6% (62/425). Os preditores independentes de risco para o fracasso foram: insuficiência renal aguda à admissão (OR 2,9; IC 95% 1,2-7,2; p=0,017), progressão radiológica (OR 29,8; IC 95 8,1-109,7%; p<0,001), derrame pleural (OR 3,4; IC 95% 1,3-8,6; p=0,010), relação PaO2/FiO2 inferior a 250 à admissão (OR 2,7; IC 95% 1,1-6,7; p=0,017) e PSI classe V (OR 2,7; IC 95% 1,1-7,0; p=0,042). A mortalidade geral foi de 7,5%, e de 40,3% nos pacientes com fracasso. O fracasso terapêutico foi o principal fator independente de mortalidade na PAC (OR 85...

Cross-cultural adaptation and validation of the European Heart Failure Self-care Behavior Scale for brazilian portuguese; Adaptação transcultural e validação da European Heart Failure Self-care Behavior Scale para o português do Brasil; Adaptación transcultural y validación de la European Heart Failure Self-care Behavior Scale para el portugués de Brasil

Feijó, Maria Karolina Echer Ferreira; Ávila, Christiane Wahast; Souza, Emiliane Nogueira de; Jaarsma, Tiny; Silva, Eneida Rejane Rabelo da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
36.32%
Objetivo: adaptar e validar a European Heart Failure Self-Care Behavior Scale para uso na lingua portuguesa do Brasil. Metodos: o processo de adaptacao cultural (traducao, sintese, retrotraducao, revisao por comite de especialistas e pre-teste) e validacao (validade de face, de conteudo e fidedignidade) foi realizado de acordo com a literatura. A European Heart Failure Self-Care Behavior Scale avalia os componentes-chave para o autocuidado: reconhecimento dos sinais e sintomas de descompensacao da insuficiencia cardiaca (IC) e a tomada de decisao na ocorrencia desses sintomas. E composta por 12 questoes (variando de 12-60, baixos escores indicam melhor autocuidado). Resultados: foram incluidos 124 pacientes com IC com idade de 62,3}12 anos. A consistencia interna das questoes apresentou um alfa de Cronbach de 0,70 e a reprodutibilidade avaliada pelo coeficiente de correlacao intraclasse foi de 0,87. Conclusao: a validade de face, de conteudo, a consistencia interna e a reprodutibilidade conferiram validade e fidedignidade ao instrumento para uso no Brasil.; Objetivo: Adaptar y validar European Heart Failure Self-Care Behavior Scale para uso en lengua portuguesa de Brasil. Metodos: El proceso de adaptacion cultural (traduccion, sintesis...

Heart Failure with Preserved Left Ventricular Ejection Fraction in Patients with Acute Myocardial Infarction

Antonelli,Lucas; Katz,Marcelo; Bacal,Fernando; Makdisse,Marcia Regina Pinho; Correa,Alessandra Graça; Pereira,Carolina; Franken,Marcelo; Fava,Anderson Nunes; Serrano Junior,Carlos Vicente; Pesaro,Antonio Eduardo Pereira
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
Relevância na Pesquisa
36.33%
Background: The prevalence and clinical outcomes of heart failure with preserved left ventricular ejection fraction after acute myocardial infarction have not been well elucidated. Objective: To analyze the prevalence of heart failure with preserved left ventricular ejection fraction in acute myocardial infarction and its association with mortality. Methods: Patients with acute myocardial infarction (n = 1,474) were prospectively included. Patients without heart failure (Killip score = 1), with heart failure with preserved left ventricular ejection fraction (Killip score > 1 and left ventricle ejection fraction ≥ 50%), and with systolic dysfunction (Killip score > 1 and left ventricle ejection fraction < 50%) on admission were compared. The association between systolic dysfunction with preserved left ventricular ejection fraction and in-hospital mortality was tested in adjusted models. Results: Among the patients included, 1,256 (85.2%) were admitted without heart failure (72% men, 67 ± 15 years), 78 (5.3%) with heart failure with preserved left ventricular ejection fraction (59% men, 76 ± 14 years), and 140 (9.5%) with systolic dysfunction (69% men, 76 ± 14 years), with mortality rates of 4.3%, 17.9%, and 27.1%...

Risk factors for ovarian failure in patients with systemic lupus erythematosus

Medeiros,M.M.C.; Silveira,V.A.L.; Menezes,A.P.T.; Carvalho,R.C.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2001 EN
Relevância na Pesquisa
36.32%
The aim of the present study was to identify the risk factors for ovarian failure in patients with systemic lupus erythematosus. Seventy-one women aged 17 to 45 years with systemic lupus erythematosus were studied. Patients were interviewed and their medical records reviewed. Demographic characteristics, clinical and serologic profiles, and menstrual and obstetric histories were recorded. Disease activity was measured by the systemic lupus erythematosus disease activity index. Serum FSH, LH, estradiol, progesterone, TSH, prolactin, and antimicrosomal and antithyroglobulin antibodies were measured. Patients who developed ovarian failure were compared to those who did not. Ovarian failure occurred in 11 patients (15.5%) and nine had premature menopause (11.3%). Cyclophosphamide administration and older patient age were found to be associated with ovarian failure. The cumulative cyclophosphamide dose was significantly higher in patients with ovarian failure than in those without this condition (18.9 vs 9.1 g; P = 0.04). The relative risk for ovarian failure in patients with cumulative cyclophosphamide dose higher than 10 g was 3.2. TSH levels were high in 100% of patients with ovarian failure who had received pulse cyclophosphamide. Ovarian failure...

The decreased oxygen uptake during progressive exercise in ischemia-induced heart failure is due to reduced cardiac output rate

Rolim,N.P.L.; Mattos,K.C.; Brum,P.C.; Baldo,M.V.C.; Middlekauff,H.R.; Negrão,C.E.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2006 EN
Relevância na Pesquisa
36.33%
We tested the hypothesis that the inability to increase cardiac output during exercise would explain the decreased rate of oxygen uptake (VO2) in recent onset, ischemia-induced heart failure rats. Nine normal control rats and 6 rats with ischemic heart failure were studied. Myocardial infarction was induced by coronary ligation. VO2 was measured during a ramp protocol test on a treadmill using a metabolic mask. Cardiac output was measured with a flow probe placed around the ascending aorta. Left ventricular end-diastolic pressure was higher in ischemic heart failure rats compared with normal control rats (17 ± 0.4 vs 8 ± 0.8 mmHg, P = 0.0001). Resting cardiac index (CI) tended to be lower in ischemic heart failure rats (P = 0.07). Resting heart rate (HR) and stroke volume index (SVI) did not differ significantly between ischemic heart failure rats and normal control rats. Peak VO2 was lower in ischemic heart failure rats (73.72 ± 7.37 vs 109.02 ± 27.87 mL min-1 kg-1, P = 0.005). The VO2 and CI responses during exercise were significantly lower in ischemic heart failure rats than in normal control rats. The temporal response of SVI, but not of HR, was significantly lower in ischemic heart failure rats than in normal control rats. Peak CI...

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients

Carvalho,Vitor Oliveira; Guimarães,Guilherme Veiga; Ciolac,Emmanuel Gomes; Bocchi,Edimar Alcides
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
36.32%
BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age...

Central Venous Pressure and Pulmonary Capillary Wedge Pressure: Fresh Clinical Perspectives from a New Model of Discordant and Concordant Heart Failure

Ma, Tony S.; Bozkurt, Biykem; Paniagua, David; Kar, Biswajit; Ramasubbu, Kumudha; Rothe, Carl F.
Fonte: Texas Heart Institute Publicador: Texas Heart Institute
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
36.32%
Heart-failure phenotypes include pulmonary and systemic venous congestion. Traditional heart-failure classification systems include the Forrester hemodynamic subsets, which use 2 indices: pulmonary capillary wedge pressure (PCWP) and cardiac index. We hypothesized that changes in PCWP and central venous pressure (CVP), and in the phenotypes of heart failure, might be better evaluated by cardiovascular modeling. Therefore, we developed a lumped-parameter cardiovascular model and analyzed forms of heart failure in which the right and left ventricles failed disproportionately (discordant ventricular failure) versus equally (concordant failure). At least 10 modeling analyses were carried out to the equilibrium state. Acute discordant pump failure was characterized by a “passive” volume movement, with fluid accumulation and pressure elevation in the circuit upstream of the failed pump. In biventricular failure, less volume was mobilized. These findings negate the prevalent teaching that pulmonary congestion in left ventricular failure results primarily from the “backing up” of elevated left ventricular filling pressure. They also reveal a limitation of the Forrester classification: that PCWP and cardiac index are not independent indices of circulation.

The Socialization of fear of failure in Japan and the United States

Mapes, Rachael Renee (1978 - ); Elliot, Andrew J.
Fonte: Universidade de Rochester Publicador: Universidade de Rochester
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
36.33%
Thesis (Ph. D.)--University of Rochester. Dept. of Clinical and Social Sciences in Psychology, 2008.; Although the deleterious effects of having a strong fear of failure motive have been well-documented, research focused on antecedents of its development is sparse. The current research focused on addressing the need for this type of research by examining shame-enhancing parenting practices and how they relate to the development of the fear of failure motive. It was hypothesized that the Japanese would be higher in fear of failure than Americans, that parent fear of failure would predict child fear of failure and that this link would be stronger for the Japanese, that Japanese parents would use shame-enhancing parenting practices more often than American parents, that shame enhancing parenting practices would mediate the relationship between parent and child fear of failure, and that these links would be stronger for the Japanese. Support was found for the hypothesis that the Japanese would be higher than Americans in the fear of failure. Mixed support was found for the hypothesis that Japanese parents use shame-enhancing practices more often. There was no support for the hypothesis that parent fear of failure predicts child fear of failure or that this link would be stronger for the Japanese...

Failure analysis and stress simulation in small multichip BGAs

Moore, Thomas D.; Jarvis, John L.
Fonte: IEEE Computer Society Publicador: IEEE Computer Society
Tipo: info:eu-repo/semantics/conferenceObject; all_ul_research; ul_published_reviewed
ENG
Relevância na Pesquisa
36.36%
peer-reviewed; This paper examines one of the common modes of structural failure in multichip ball grid arrays (BGAs), determines its locations within the package structure, relates it to the stresses generated in the reliability tests under which it occurs, and by finite element simulations, determines an explanation for the failure, and finally proposes a method to avoid this failure mechanism. Several designs of multichipBGAsubstrates were manufactured and production silicon assembled into them. These were all 14 mm 22 mm 119 ball PBGA. These were subjected to a set of package reliability tests, until some units failed electrical test. The failed units were analyzed and the physical location and shape of the failure was determined in many cases. From this information, the mechanical mode of failure for each unit was determined. In addition there was sufficient information in some of the analyses to provide definite suggestions as to the mechanism of failure. Meanwhile, finite element analysis was performed using simplified representations of the multichip BGAs, in order to find the locations of highest stress, and the expected modes of failure. This data was matched to the failure modes found in the physical analysis. Some novel failure analysis techniques were used to expose the damage in the failed units. A particular failure mode occurred frequently in temperature cycle...

Understanding and Improving the Efficiency of Failure Resilience for Big Data Frameworks

Dinu, Florin
Fonte: Universidade Rice Publicador: Universidade Rice
Relevância na Pesquisa
36.32%
Big data processing frameworks (MapReduce, Hadoop, Dryad) are hugely popular today because they greatly simplify the management and deployment of big data analysis jobs requiring the use of many machines in parallel. A strong selling point is their built-in failure resilience support. Big data frameworks can run computations to completion despite occasional failures in the system. However, an important but overlooked point has been the efficiency of their failure resilience. The vision of this thesis is that big data frameworks should not only be failure resilient but that they should provide the resilience in an efficient manner with minimum impact on computations both under failures as well as during failure-free periods. To this end, the first part of the thesis presents the first in-depth analysis of the efficiency of the failure resilience provided by the popular Hadoop framework under failures. The results show that even single machine failures can lead to large, variable and unpredictable job running times. This thesis determines the causes behind this inefficient behavior and points out the responsible Hadoop mechanisms and their limitations. The second part of the thesis focuses on providing efficient failure resilience for the case of computations comprised of multiple jobs. We present the design...

Heart Failure with Preserved Left Ventricular Ejection Fraction in Patients with Acute Myocardial Infarction

Antonelli,Lucas; Katz,Marcelo; Bacal,Fernando; Makdisse,Marcia Regina Pinho; Correa,Alessandra Graça; Pereira,Carolina; Franken,Marcelo; Fava,Anderson Nunes; Serrano Junior,Carlos Vicente; Pesaro,Antonio Eduardo Pereira
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 EN
Relevância na Pesquisa
36.33%
AbstractBackground:The prevalence and clinical outcomes of heart failure with preserved left ventricular ejection fraction after acute myocardial infarction have not been well elucidated.Objective:To analyze the prevalence of heart failure with preserved left ventricular ejection fraction in acute myocardial infarction and its association with mortality.Methods:Patients with acute myocardial infarction (n = 1,474) were prospectively included. Patients without heart failure (Killip score = 1), with heart failure with preserved left ventricular ejection fraction (Killip score > 1 and left ventricle ejection fraction ≥ 50%), and with systolic dysfunction (Killip score > 1 and left ventricle ejection fraction < 50%) on admission were compared. The association between systolic dysfunction with preserved left ventricular ejection fraction and in-hospital mortality was tested in adjusted models.Results:Among the patients included, 1,256 (85.2%) were admitted without heart failure (72% men, 67 ± 15 years), 78 (5.3%) with heart failure with preserved left ventricular ejection fraction (59% men, 76 ± 14 years), and 140 (9.5%) with systolic dysfunction (69% men, 76 ± 14 years), with mortality rates of 4.3%, 17.9%, and 27.1%, respectively (p < 0.001). Logistic regression (adjusted for sex...

Posthepatectomy liver failure: A definition and grading by the International Study Group of Liver Surgery (ISGLS)

Rahbari, N.; Garden, J.; Padbury, R.; Brooke-Smith, M.; Crawford, M.; Adam, R.; Koch, M.; Makuuchi, M.; DeMatteo, R.; Christophi, C.; Banting, S.; Usatoff, V.; Nagino, M.; Maddern, G.; Hugh, T.; Vauthey, J.N.; Greig, P.; Rees, M.; Yokoyama, Y.; Sheung, T.
Fonte: Mosby Inc Publicador: Mosby Inc
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
36.35%
BACKGROUND: Posthepatectomy liver failure is a feared complication after hepatic resection and a major cause of perioperative mortality. There is currently no standardized definition of posthepatectomy liver failure that allows valid comparison of results from different studies and institutions. The aim of the current article was to propose a definition and grading of severity of posthepatectomy liver failure. METHODS: A literature search on posthepatectomy liver failure after hepatic resection was conducted. Based on the normal course of biochemical liver function tests after hepatic resection, a simple and easily applicable definition of posthepatectomy liver failure was developed by the International Study Group of Liver Surgery. Furthermore, a grading of severity is proposed based on the impact on patients' clinical management. RESULTS: No uniform definition of posthepatectomy liver failure has been established in the literature addressing hepatic surgery. Considering the normal postoperative course of serum bilirubin concentration and International Normalized Ratio, we propose defining posthepatectomy liver failure as the impaired ability of the liver to maintain its synthetic, excretory, and detoxifying functions, which are characterized by an increased international normalized ratio and concomitant hyperbilirubinemia (according to the normal limits of the local laboratory) on or after postoperative day 5. The severity of posthepatectomy liver failure should be graded based on its impact on clinical management. Grade A posthepatectomy liver failure requires no change of the patient's clinical management. The clinical management of patients with grade B posthepatectomy liver failure deviates from the regular course but does not require invasive therapy. The need for invasive treatment defines grade C posthepatectomy liver failure. CONCLUSION: The current definition of posthepatectomy liver failure is simple and easily applicable in clinical routine. This definition can be used in future studies to allow objective and accurate comparisons of operative interventions in the field of hepatic surgery.; Nuh N. Rahbari... Guy Maddern... et al.

Software Architecture-Based Failure Prediction

Mohamed, ATEF
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
36.33%
Depending on the role of software in everyday life, the cost of a software failure can sometimes be unaffordable. During system execution, errors may occur in system components and failures may be manifested due to these errors. These errors differ with respect to their effects on system behavior and consequent failure manifestation manners. Predicting failures before their manifestation is important to assure system resilience. It helps avoid the cost of failures and enables systems to perform corrective actions prior to failure occurrences. However, effective runtime error detection and failure prediction techniques encounter a prohibitive challenge with respect to the control flow representation of large software systems with intricate control flow structures. In this thesis, we provide a technique for failure prediction from runtime errors of large software systems. Aiming to avoid the possible difficulties and inaccuracies of the existing Control Flow Graph (CFG) structures, we first propose a Connection Dependence Graph (CDG) for control flow representation of large software systems. We describe the CDG structure and explain how to derive it from program source code. Second, we utilize the proposed CDG to provide a connection-based signature approach for control flow error detection. We describe the monitor structure and present the error checking algorithm. Finally...

Failure probabilities associated with failure regions containing the origin: application to corroded pressurized pipelines

Alamilla,J.L.; Oliveros,J.; García-Vargas,J.; Pérez,R.
Fonte: Sociedad Mexicana de Física Publicador: Sociedad Mexicana de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2006 EN
Relevância na Pesquisa
36.33%
This work develops expressions to calculate failure probabilities associated with failure regions containing the expected value of random variables in the standard space (origin). These expressions are an extension based on the classical case that calculates failure probabilities associated with non-origin-containing failure regions. A simple form is established to know whether the failure region is origin- o non-origin-containing and to calculate the failure probability associated with the region in question. It is shown through an example of corroded pressurized pipelines that such an extension may be necessary to calculate failure probabilities in practical conditions. Reliability methods analyzed are FORM and directional simulation.