295 research outputs found

    Medidas de constante de Hall e resistividade em função da temperatura : aplicação no GaAs dopado com Mn

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    Orientador: Marcio D'Olne CamposDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb WataghinResumo: Não informadoAbstract: Not informed.MestradoFísicaMestre em Físic

    Lightning risk warnings based on atmospheric electric field measurements in Brazil

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    This paper presents a methodology that employs the electrostatic field variations caused by thundercloud formation or displacement to generate lightning warnings over a region of interest in Southeastern Brazil. These warnings can be used to prevent accidents during hazardous operations, such as the manufacturing, loading, and test of motor-rockets. In these cases, certain equipment may be moved into covered facilities and personnel are required to take shelter. It is also possible to avoid the threat of natural and triggered lightning to launches. The atmospheric electric field database, including the summer seasons of 2007/2008 and 2008/2009 (from November to February), and, for the same period and region, the cloud-to-ground lightning data provided by the Brazilian lightning detection network – BrasilDAT – were used in order to perform a comparative analysis between the lightning warnings and the cloud-to- ground lightning strikes that effectively occurred inside the area of concern. The analysis was done for three areas surrounding the sensor installation defined as circles with 5, 10 and 15 km of radius to determine the most effective detection range. For each area it was done using several critical electric field thresholds: +/- 0.5; +/- 0.8; +/- 0.9; +/- 1.0; +/- 1.2; and +/- 1.5 kV/m. As a result of the reduction of atmospheric electric field data provided by the sensor installed in area of concern and lightning provided by BrasilDAT, it was possible, for each of the areas of alert proposals, to obtain the following parameters: the number of effective alarms; the number of false alarms; and the number of failure to warning. From the analysis of these parameters, it was possible to conclude that, apparently, the most interesting critical electric field threshold to be used is the level of 0.9 kV/m in association with a distance range of 10 km around the point where the sensor is installed

    Clinical impact of myocardial ischemia and viability after treatment of proximal left anterior descending artery chronic total occlusions

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    BACKGROUND: Evaluation of myocardial ischemia and viability is recommended prior to percutaneous coronary intervention (PCI) for chronic total occlusions. We evaluated late adverse cardiovascular events of patients with PCI for proximal left anterior descending artery occlusions, comparing patients with or without myocardial ischemia or viability. METHODS: Patients were allocated to groups with myocardial ischemia/viability (G1, n = 91) and without myocardial ischemia/viability (G2, n = 65) and adverse cardiovascular events (death, myocardial infarction, target-vessel revascularization and congestive heart failure) were compared. RESULTS: Most patients were male (68.1% vs 69.2%; P = 0.56), with a mean age of 65.4 ± 10 years vs 63.5 ± 8.7 years (P = 0.61) and almost one third were diabetics (33% vs 29.2%; P = 0.76). No differences regarding the clinical and angiographic profile were observed, except for the left ventricular ejection fraction (48.6 ± 13.7% vs 39.5 ± 11.8%; P = 0.04) and the degree of angiographic collateral flow grade to the left anterior descending artery, which was more evident in G1 (P = 0.03). The 3-year follow-up incidence of composite adverse cardiovascular events was lower in patients with myocardial ischemia/viability (12.5% vs 31.1%; P < 0.01). The factors that contributed the most for this difference were the incidence of congestive heart failure (3.3% vs 15.3%; P = 0.02) and death (2.2% vs 7.7%; P = 0.13). CONCLUSIONS: Treatment of proximal left anterior descending artery chronic total occlusions in patients with evidence of myocardial ischemia or viability reduces the incidence of adverse cardiovascular events in the long term.INTRODUÇÃO: A avaliação da isquemia e viabilidade miocárdicas é recomendável antes da intervenção coronária percutânea (ICP) em oclusões crônicas. Avaliamos os eventos cardiovasculares adversos tardios de pacientes com ICP da oclusão crônica no segmento proximal da artéria descendente anterior, comparando pacientes de acordo com a presença ou não de isquemia ou viabilidade miocárdicas. MÉTODOS: Os pacientes foram alocados nos grupos com isquemia/viabilidade miocárdicas (G1, n = 91) e sem isquemia/viabilidade miocárdicas (G2, n = 65) e avaliados os eventos clínicos combinados tardios (óbito, infarto do miocárdio, revascularização do vaso-alvo e insuficiência cardíaca congestiva). RESULTADOS: A maioria dos pacientes era do sexo masculino (68,1% vs. 69,2%; P = 0,56), com média de idade de 65,4 ± 10,4 anos vs. 63,5 ± 8,7 anos (P = 0,61), e quase um terço era de diabéticos (33% vs. 29,2%; P = 0,76). Os grupos não mostraram diferenças em relação ao perfil clínico-angiográfico, com exceção da fração de ejeção do ventrículo esquerdo (48,6 ± 13,7% vs. 39,5 ± 11,8%; P = 0,04) e do grau de circulação colateral para a artéria descendente anterior, mais evidente no G1 (P = 0,03). A incidência de eventos clínicos combinados em um período de três anos foi menor nos pacientes com isquemia/viabilidade miocárdicas (12,5% vs. 31,1%; P < 0,01). Os fatores que mais contribuíram para essa diferença foram a incidência de insuficiência cardíaca congestiva (3,3% vs. 15,3%; P = 0,02) e óbito (2,2% vs. 7,7%; P = 0,13). CONCLUSÕES: O tratamento de oclusão crônica no segmento proximal da artéria descendente anterior com stent farmacológico, em pacientes com evidência de isquemia ou viabilidade miocárdicas, reduz eventos clínicos a longo prazo.Hospital Beneficência Portuguesa de São PauloHospital Beneficência Portuguesa de São Paulo Equipe de Cardiologia Intervencionista-Wilson PimentelUniversidade Federal de São Paulo (UNIFESP) Hospital do Rim e HipertensãoUNIFESP, Hospital do Rim e HipertensãoSciEL

    Polar S810 as an alternative resource to the use of the electrocardiogram in the 4-second exercise test

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    BACKGROUND: The 4-second exercise test (T4s) evaluates the cardiac vagal tone during the initial heart rate (HR) transient at sudden dynamic exercise, through the identification of the cardiac vagal index (CVI) obtained from the electrocardiogram (ECG). OBJECTIVE: To evaluate the use of the Polar S810 heart rate monitor (HRM) as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. METHODS: In this study, 49 male individuals (25 ± 20 years, 176 ±12 cm, 74 ± 6 kg) underwent the 4-second exercise test. The RR intervals were recorded simultaneously by ECG and HRM. We calculated the mean and the standard deviation of the last RR interval of the pre-exercise period, or of the first RR interval of the exercise period, whichever was longer (RRB), of the shortest RR interval of the exercise period (RRC), and of the CVI obtained by ECG and HRM. We used the Student t-test for dependent samples (p < 0.05) to test the significance of the differences between means. To identify the correlation between the ECG and the HRM, we used the linear regression to calculate the Pearson's correlation coefficient and the strategy proposed by Bland and Altman. RESULTS: Linear regression showed r2 of 0.9999 for RRB, 0.9997 for RRC, and 0.9996 for CVI. Bland e Altman strategy presented standard deviation of 0.92 ms for RRB, 0.86 ms for RRC, and 0.002 for CVI. CONCLUSION: Polar S810 HRM was more efficient in the application of T4s compared to the ECG.FUNDAMENTO: O teste de exercício de 4 segundos (T4s) avalia o tônus vagal cardíaco durante o transiente inicial da frequência cardíaca (FC), em exercício dinâmico súbito, por meio da identificação do índice vagal cardíaco (IVC) obtido a partir do eletrocardiograma (ECG). OBJETIVO: Testar a utilização do monitor de frequência cardíaca (MFC) Polar S810 como recurso alternativo ao ECG na aplicação do T4s. MÉTODOS: Neste trabalho, 49 indivíduos do sexo masculino (25 ± 20 anos, 176 ± 12 cm, 74 ± 6 kg) realizaram o T4s. Os intervalos RR foram registrados simultaneamente por ECG e MFC. Calcularam-se média e desvio padrão do último intervalo RR do período pré-exercício ou o primeiro do período de exercício, aquele que for mais longo (RRB), do mais curto intervalo RR do período de exercício (RRC) e do IVC obtidos por ECG e MFC. Utilizou-se o teste t de Student para amostras dependentes (p < 0,05) para testar a significância das diferenças entre as médias. Para identificar a concordância entre o ECG e o MFC, utilizou-se a regressão linear, com cálculo do coeficiente de correlação de Pearson e a estratégia proposta por Bland e Altman. RESULTADOS: A regressão linear apresentou r2 de 0,9999 para o RRB, 0,9997 para o RRC e 0,9996 para o IVC. A estratégia de Bland e Altman apresentou desvio padrão de 0,92 ms para o RRB, 0,86 ms para o RRC e 0,002 para o IVC. CONCLUSÃO: O MFC Polar S810 se mostrou eficiente na aplicação do T4s quando comparado ao ECG

    Performance of the Titanium-Nitride-Oxide Coated Stent in Patients with Multivessel Coronary Artery Disease

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    ABSTRACTBackgroundTo date, there are no studies evaluating the use of the titanium-nitride-oxide coated stent in patients with multivessel coronary artery disease. We have compared the performance of the Titan-2® stent to that of the second generation drug-eluting stents in this scenario.MethodsFrom 2011 to 2012, 284 patients were treated with the Titan-2® stent, of which 100 (35.2%) had multivessel coronary artery disease. This group was compared to 100 patients, of a group of 304 (38.9%) patients with multivessel coronary artery disease treated with second generation drug-eluting stents with durable or biodegradable polymers. The primary endpoint was the occurrence of major adverse cardiovascular events at 1 year.ResultsClinical, angiographic and procedure-related characteristics of the patients did not show differences between groups. Most patients in the Titan-2® group were male (70%), mean age was 68.4 ± 12.9 years and 25% were diabetic. Stable symptomatic patients were prevalent (68%), 51% had three-vessel disease and ventricular function was preserved (55.6 ± 12.7%). The incidence of major adverse cardiovascular events at 1 year in the Titan-2® group was 21% (vs. 17%; p = 0.59), death was observed in 3% (vs. 2%; p > 0.99) of the patients, acute myocardial infarction in 5% (vs. 4%; p > 0.99) and a new revascularization procedure in 13% (vs. 11%; p = 0.83). Definitive stent thrombosis was not observed in either group.ConclusionsThe Titan-2® stent showed similar results to those of the second-generation drug-eluting stents, which makes it attractive for use in the complex scenario of patients with multivessel coronary artery disease.RESUMODesempenho do Stent Recoberto por Titânio-Óxido Nítrico em Pacientes com Doença Coronária MultiarterialIntrodçãoAté o momento, nenhum estudo avaliou o stent recoberto por titânio-óxido nítrico em pacientes com doença arterial coronariana multiarterial. Comparamos o desempenho do stent Titan-2® ao stents farmacológicos de segunda geragao nesse cenário.MétodosNo período de 2011 a 2012, 284 pacientes foram tratados com o stent Titan-2®, dos quais 100 (35,2%) eram portadores de doença arterial coronariana multiarterial. Esse grupo foi comparado a 100 pacientes, de um grupo de 304 (38,9%), com doença arterial coronariana multiarterial, tratados com o stent farmacológico de segunda geração com polímeros duráveis ou biodegradáveis. O desfecho primário foi a ocorrência de eventos cardíacos adversos maiores em 1 ano.ResultadosCaracterísticas clínicas, angiográficas e do procedimento não apresentaram diferenças entre os grupos. A maioria dos pacientes do grupo Titan-2® era do sexo masculino (70%), com idade de 68,4 ± 12,9 anos e 25% eram diabéticos. Predominaram os quadros clínicos estáveis (68%), 51% tinham acometimento triarterial e a função ventricular estava preservada. A incidência de eventos cardiovasculares adversos maiores em 1 ano no grupo Titan-2® foi de 21% (vs. 17%; p = 0,59), óbito ocorreu em 3% (vs. 2%; p > 0,99) dos pacientes, infarto do miocárdio em 5% (vs. 4%; p > 0,99) e nova revascularização miocárdica em 13% (vs. 11%; p = 0,83). Não foram constatadas tromboses de stent definitivas em nenhum grupo.ConclusõesO uso do Titan-2® apresentou resultados similares aos do stent farmacológico de segunda geração, o que o torna atrativo para ser utilizado no complexo cenário de pacientes portadores de doença arterial coronariana multiarterial

    Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

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    : The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p &lt; 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

    Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

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    Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

    Gestión del conocimiento. Perspectiva multidisciplinaria. Volumen 7

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    El libro “Gestión del Conocimiento. Perspectiva Multidisciplinaria”, volumen 7, de la Colección Unión Global, es resultado de investigaciones. Los capítulos del libro, son resultados de investigaciones desarrolladas por sus autores. El libro es una publicación internacional, seriada, continua, arbitrada de acceso abierto a todas las áreas del conocimiento, que cuenta con el esfuerzo de investigadores de varios países del mundo, orientada a contribuir con procesos de gestión del conocimiento científico, tecnológico y humanístico que consoliden la transformación del conocimiento en diferentes escenarios, tanto organizacionales como universitarios, para el desarrollo de habilidades cognitivas del quehacer diario. La gestión del conocimiento es un camino para consolidar una plataforma en las empresas públicas o privadas, entidades educativas, organizaciones no gubernamentales, ya sea generando políticas para todas las jerarquías o un modelo de gestión para la administración, donde es fundamental articular el conocimiento, los trabajadores, directivos, el espacio de trabajo, hacia la creación de ambientes propicios para el desarrollo integral de las instituciones

    Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

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    Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure &lt; 100 mmHg (n = 1127), estimated glomerular filtration rate &lt; 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
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