989 resultados para signal characteristics


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Supplementary data associated with this article can be found, in the online version, at: http://dx.doi.org/10.1016/j.electacta.2015.09.169.

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OBJECTIVE: To determine the characteristics associated with the dropout of patients followed up in a Brazilian out patient clinic specializing in hypertension. METHODS: Planned prospective cohort study of patients who were prescribed an antihypertensive treatment after an extensive initial evaluation. The following parameters were analyzed: sex, age, educational level, duration of disease, pressure level used for classifying the patient, previous treatment, physical activity, smoking, alcohol consumption, familial history of hypertension, and lesion in a target organ. RESULTS: We studied 945 hypertensive patients, 533 (56%) of whom dropped out of the follow-up. The mean age was 52.312.9 years. The highest probabilities of dropout of the follow-up were associated with current smoking, relative risk of 1.46 (1.04-2.06); educational level equal to or below 5 years of schooling, relative risk of 1.52 (1.11-2.08); and hypertension duration below 5 years, relative risk of 1.78 (1.28-2.48). Age increase was associated with a higher probability of follow-up with a relative risk of 0.98 (0.97-0.99). CONCLUSION: We identified a group at risk for dropping out the follow-up, which comprised patients with a lower educational level, a recent diagnosis of hypertension, and who were smokers. We think that measures assuring adherence to treatment should be directed to this group of patients.

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OBJECTIVE: Using P-wave signal-averaged electrocardiography, we assessed the patterns of atrial electrical activation in patients with idiopathic atrial fibrillation as compared with patterns in patients with atrial fibrillation associated with structural heart disease. METHODS: Eighty patients with recurrent paroxysmal atrial fibrillation were divided into 3 groups as follows: group I - 40 patients with atrial fibrillation associated with non-rheumatic heart disease; group II - 25 patients with rheumatic atrial fibrillation; and group III - 15 patients with idiopathic atrial fibrillation. All patients underwent P-wave signal-averaged electrocardiography for frequency-domain analysis using spectrotemporal mapping and statistical techniques for detecting and quantifying intraatrial conduction disturbances. RESULTS: We observed an important fragmentation in atrial electrical conduction in 27% of the patients in group I, 64% of the patients in group II, and 67% of the patients in group III (p=0.003). CONCLUSION: Idiopathic atrial fibrillation has important intraatrial conduction disturbances. These alterations are similar to those observed in individuals with rheumatic atrial fibrillation, suggesting the existence of some degree of structural involvement of the atrial myocardium that cannot be detected with conventional electrocardiography and echocardiography.

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OBJECTIVE: To assess the clinical, electrocardiographic, and electrophysiologic characteristics of patients (pt) with intra-His bundle block undergoing an electrophysiologic study (EPS). METHODS: We analyzed the characteristics of 16 pt with second-degree atrioventricular block and symptoms of syncope or dyspnea, or both, undergoing conventional EPS. RESULTS: Intra-His bundle block was documented in 16 pt during an EPS. In 15 (94%) pt, the atrioventricular block was recorded in sinus rhythm; 4 (25%) pt had intra-His Wenckebach phenomenon, which correlated with Mobitz I (MI) atrioventricular block on the electrocardiogram. Seven (44%) pt had 2:1 atrioventricular block, 2 of whom were asymptomatic (12.5%). One (6%) pt had intra- and infra-His bundle block. Clinically, 11 (68%) pt had syncope or presyncope, 3 (18%) had dyspnea on exertion, and 2 (12.5%) were asymptomatic. Eight (50%) pt had bundle-branch block as follows: 4 (25%) pt had left bundle-branch block, and 4 (25%) had right bundle-branch block. Left anterosuperior divisional block was observed in 3 pt (19%), 2 of whom with associated right bundle-branch block. CONCLUSION: Intra-His bundle block was observed in 11% of the pt with second-degree atrioventricular block, syncope or presyncope, or both, it being the most frequent clinical presentation. Intra-His bundle block was more common in the elderly (> 60 years) and among females. The most frequent electrocardiographic presentations were second-degree Mobitz I or type 2:1 atrioventricular block.

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OBJECTIVE: To assess the prevalence of white-coat normortension, white-coat hypertension, and white-coat effect. METHODS: We assessed 670 medical records of patients from the League of Hypertension of the Hospital das Clnicas of the Medical School of the University of So Paulo. White-coat hypertension (blood pressure at the medical office: mean of 3 measurements with the oscillometric device <FONT FACE=Symbol>&sup3;</FONT>140 or <FONT FACE=Symbol>&sup3;</FONT>90 mmHg, or both, and ambulatory blood pressure monitoring mean during wakefulness < 135/85) and white-coat normotension (office blood pressure < 140/90 and blood pressure during wakefulness on ambulatory blood pressure monitoring <FONT FACE=Symbol>&sup3;</FONT> 135/85) were analyzed in 183 patients taking no medication. The white-coat effect (difference between office and ambulatory blood pressure > 20 mmHg for systolic and 10 mmHg for diastolic) was analyzed in 487 patients on treatment, 374 of whom underwent multivariate analysis to identify the variables that better explain the white-coat effect. RESULTS: Prevalence of white-coat normotension was 12%, prevalence of white-coat hypertension was 20%, and prevalence of the white-coat effect was 27%. A significant correlation (p<0.05) was observed between white-coat hypertension and familial history of hypertension, and between the white-coat effect and sex, severity of the office diastolic blood pressure, and thickness of left ventricular posterior wall. CONCLUSION: White-coat hypertension, white-coat normotension, and white-coat effect should be considered in the diagnosis of hypertension.

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OBJECTIVE: To assess signal-averaged electrocardiogram (SAECG) for diagnosing incipient left ventricular hypertrophy (LVH). METHODS: A study with 115 individuals was carried out. The individuals were divided as follows: GI - 38 healthy individuals; GII - 47 individuals with mild to moderate hypertension and normal findings on echocardiogram and ECG; and GIII - 30 individuals with hypertension and documented LVH. The magnitude vector of the SAECG was analyzed with the high-pass cutoff frequency of 40 Hz through the bidirectional four-pole Butterworth high-pass digital filter. The mean quadratic root of the total QRS voltage (RMST) and the two-dimensional integral of the QRS area of the spectro-temporal map were analyzed between 0 and 30 Hz for the frequency domain (Int FD), and between 40 and 250 Hz for the time domain (Int TD). The electrocardiographic criterion for LVH was based on the Cornell Product. Left ventricular mass was calculated with the Devereux formula. RESULTS: All parameters analyzed increased from GI to GIII, except for Int FD (GII vs GIII) and RMST log (GII vs GIII). Int TD showed greater accuracy for detecting LVH with an appropriate cutoff > 8 (sensitivity of 55%, specificity of 81%). Positive values (> 8) were found in 56.5% of the G II patients and in 18.4% of the GI patients (p< 0.0005). CONCLUSION: SAECG can be used in the early diagnosis of LVH in hypertensive patients with normal ECG and echocardiogram.

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OBJECTIVE: To obtain information about the profile and behavior of a population with ischemic heart disease undergoing cine coronary angiography and to determine disease severity. METHODS: Retrospective study assessing patients hospitalized at InCor from 1986 to 1995, in which the variables age, sex, and number of major coronary arteries with obstruction degree > 40% were analyzed. RESULTS: We studied 18,221 patients and observed a significant increase in the number of females (22.8% to 25.2%, P=0.001) and an increase in age (57.129.3 to 60.410.7 years, P=0.0001). A significant increase in the incidence of multivessel disease was observed, which was more frequent among males (69.2% and 64.5%) and among the older patients (59.89.8 and 56.810.7 years, P=0.0001). A reduction in the incidence of single-vessel disease was also observed (66.2% vs 69.2% and 33.8% vs 30.5%, respectively, P<0.0001). CONCLUSION: A change in the profile of the population studied was observed as follows: patients undergoing cine coronary angiography at InCor were older, had a greater number of impaired major coronary arteries, and the number of females affected increased, leading to indices suggestive of a poorer prognosis.

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Trypanosoma cruzi es un protozoo primitivo agente causal de la enfermedad de Chagas. La transmisin de esta enfermedad depende tanto del desarrollo y de la diferenciacin del microorganismo en el intestino del vector. Las diferentes formas del parsito se han adaptado a una serie de condiciones impuestas por los distintos ambientes en donde debi habitar. Esta capacidad de sobrevivir a medios externos tan variados est dada por la diversidad en las vas de transduccin de seales en el parsito. T. cruzi se multiplica y diferencia (metaciclognesis) en el recto de los triatominos. A este nivel, los parsitos se enfrentan a un incremento en la osmolaridad causado por un elevado contenido de NaCl en la orina. En nuestro laboratorio se observ que diferentes estmulos son capaces de producir incrementos en los niveles de IP3 y de Ca2+ intracelular, consecuencia de la activacin del ciclo del inositol fosfato, y activacin de fosfolipasa D (PLD) y fosfatidilinositol 3 quinasa (PI3K). En un medio carente de Na+ los epimastigotes estimulados con carbacol, mostraron una seal de calcio disminuida mientras que la acumulacin de IP3 no se modific. Adems, esta seal se increment en presencia de PMA, activador de protena quinasa C, mientras que la acumulacin de IP3 se anul completamente. Estos resultados indujeron a pensar en un mecanismo alternativo y/o paralelo a IP3 en la liberacin de Ca2+, en el cual la presencia de un intercambiador Na+/H+ favorecera la liberacin del ion desde organelas acdicas. Es conocido que la seal de calcio es requerida para la metaciclognesis, y que esta seal es independiente del Ca2+ extracelular (Lammel y col. 1996, Marchesini y col., 2002). De este modo se propone que "los epimastigotes de T. cruzi utilizan como elementos conservados a lo largo de la evolucin a los elementos del ciclo del inositol fosfato, uno de los sistemas de transduccin de seales ms antiguo, para responder a estmulos que inducen la diferenciacin del parsito". Por lo tanto, para el desarrollo de este proyecto se propone determinar la presencia de un RcIP3 en epimastigotes y conocer su compromiso en la liberacin de Ca2+ desde reservorios intracelulares. Adems, establecer si un intercambiador Na+/H+ en membrana de acidocalcisomas estara relacionado con la seal de calcio intracelular y su posible regulacin por proteina quinasa C y A (PKC y PKA, respectivamente). Por otro lado, para dilucidar la implicancia de estos mecanismos en el proceso de metaciclognesis, se propone estudiar la activacin del intercambiador Na+/H+ y la seal de calcio en condiciones de hiperosmolaridad, tal como ocurre en el recto del triatomino. Ademas, ya que el proceso de diferenciacin involucra una reorganizacin de los microtubulos del citoesqueleto se pretende estudiar el compromiso del metabolismo de fosfolpidos y tubulina en procesos que contribuyen a la induccin de la metaciclogenesis. El alcance de los objetivos mencionados ayudar a dilucidar la presencia de componentes tales como RcIP3 y el intercambiador Na+/H+ involucrados en la sealizacin del ion bivalente. Por otro lado, se espera demostrar que los isotipos de tubulina encontrados en <i>T. cruzi</i> cambien en cantidad relativa y nivel de expresin cuando los epimastigotes sean estimulados con posibles inductores de la diferenciacin. Adems, se espera observar simultneamente un aumento en la actividad de dos enzimas relacionadas con la reorganizacin de microtbulos: PI-3K y PLD. En tal caso, y para comprobar su implicancia en el proceso, se espera que la inhibicin de tales enzimas sea capaz de revertir el efecto producido por los estmulos. Como la PLC se expresa principalmente en las forma epimastigotes mas que en los tripomastigotes (forma infectiva), la seal de Ca2+ inducida por IP3 se relacionara con la capacidad del parsito para responder a ciertos cambios de pH y osmolaridad que enfrenta el microorganismo en el tracto digestivo del insecto vector.

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Plaice (Pleuronectes platessa, L.) and dab (Limanda limanda, L.) are among the most abundant flatfishes in the north-eastern Atlantic region and the dominant species in shallow coastal nursery grounds. With increasing pressures on commercial flatfish stocks in combination with changing coastal environments, better knowledge of population dynamics during all life stages is needed to evaluate variability in year-class strength and recruitment to the fishery. The aim of this research was to investigate the complex interplay of biotic and abiotic habitat components influencing the distribution, density and growth of plaice and dab during the vulnerable juvenile life stage and to gain insight in spatial and temporal differences in nursery habitat quality along the west coast of Ireland. Intraspecific variability in plaice diet was observed at different spatial scales and showed a link with condition, recent growth and morphology. This highlights the effect of food availability on habitat quality and the need to consider small scale variation when attempting to link habitat quality to feeding, growth and condition of juvenile flatfish. There was evidence of trophic, spatial and temporal resource partitioning between juvenile plaice and dab allowing the co-existence of morphologically similar species in nursery grounds. In the limited survey years there was no evidence that the carrying capacity of the studied nursery grounds was reached but spatial and interannual variations in fish growth indicated fluctuating environments in terms of food availability, predator densities, sediment features and physico-chemical conditions. Predation was the most important factor affecting habitat quality for juvenile plaice and dab with crab densities negatively correlated to fish condition whereas shrimp densities were negatively associated with densities of small-sized juveniles in spring. A comparison of proxies for fish growth showed the advantage of Fultons K for routine use whereas RNA:DNA ratios proved less powerful when short-term environmental fluctuations are lacking. This study illustrated how distinct sets of habitat features can drive spatial variation in density and condition of juvenile flatfish highlighting the value of studying both variables when modeling habitat requirements. The habitat models generated in this study also provide a powerful tool to predict potential climate and anthropogenic impacts on the distribution and condition of juveniles in flatfish nurseries. The need for effective coastal zone management was emphasized to ensure a sustainable use of coastal resources and successful flatfish recruitment to the fishery.

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Results are presented from the analysis of observations data on flash flood in Georgia over a period of 45 years, from 1961 to 2005, provided of the of Hydro-meteorology Service of Georgia.

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The results of the stationary and expeditionary investigations of the light ions content in surface boundary layer in the urban and ecologically clean locality for different regions of Georgia are represented.

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Magdeburg, Univ., Fak. fr Wirtschaftswiss., Diss., 2011

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Free Tube Jet - Impingemenet - Heat Transfer - Arrary - Infrared Techuique - Hole Channels - Heat Transfer Uniformaty

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Ground penetrating radar; landmine; background clutter removal, buried targets detecting