916 resultados para Sampling (Statistics)


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We discuss the development and performance of a low-power sensor node (hardware, software and algorithms) that autonomously controls the sampling interval of a suite of sensors based on local state estimates and future predictions of water flow. The problem is motivated by the need to accurately reconstruct abrupt state changes in urban watersheds and stormwater systems. Presently, the detection of these events is limited by the temporal resolution of sensor data. It is often infeasible, however, to increase measurement frequency due to energy and sampling constraints. This is particularly true for real-time water quality measurements, where sampling frequency is limited by reagent availability, sensor power consumption, and, in the case of automated samplers, the number of available sample containers. These constraints pose a significant barrier to the ubiquitous and cost effective instrumentation of large hydraulic and hydrologic systems. Each of our sensor nodes is equipped with a low-power microcontroller and a wireless module to take advantage of urban cellular coverage. The node persistently updates a local, embedded model of flow conditions while IP-connectivity permits each node to continually query public weather servers for hourly precipitation forecasts. The sampling frequency is then adjusted to increase the likelihood of capturing abrupt changes in a sensor signal, such as the rise in the hydrograph – an event that is often difficult to capture through traditional sampling techniques. Our architecture forms an embedded processing chain, leveraging local computational resources to assess uncertainty by analyzing data as it is collected. A network is presently being deployed in an urban watershed in Michigan and initial results indicate that the system accurately reconstructs signals of interest while significantly reducing energy consumption and the use of sampling resources. We also expand our analysis by discussing the role of this approach for the efficient real-time measurement of stormwater systems.

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A utilização de uma emergência por pacientes com problemas médicos eletivos contribui para a demanda excessiva e impede de acesso a pacientes com emergência verdadeira. O presente estudo se propôs: (1) investigar as características do usuário da emergência em relação a aspectos demográficos, local de moradia e tempo que apresenta os sintomas que o levaram a consultar; (2) identificar as diferenças da demanda entre o final de semana e durante a semana; (3) investigar a prevalência de saúde mental, alcoolismo, doença coronariana e hipertensão; (4) avaliar como é a utilização e o acesso a serviços de saúde para pacientes que referem ter um médico definido em comparação com quem refere não ter; (5) avaliar a satisfação dos pacientes com o atendimento na emergência e (6) verificar se o atendimento através de um médico definido ou em serviço de atenção primária em saúde diminui o afluxo de casos não urgentes aos serviços de emergência. Foi realizado um estudo transversal na Emergência do Hospital N.S. da Conceição de Porto Alegre (RS) no período de 6 de janeiro a 25 de junho de 1996, tendo sido incluídos 20 dias escolhidos entre o meio-dia de sábado e o meio-dia de domingo, para caracterizar a demanda do final de semana, e o meio-dia de segunda-feira e meio-dia de terça-feira, para a dos outros dias. Fizeram parte da amostra 553 pacientes selecionados através de amostragem aleatória sistemática, com uma taxa de resposta de 88%. A coleta de dados consistiu de questionário de 156 questões aplicado aos pacientes. O registro e análise dos dados foram realizados utilizando-se os programas Epi-Info, EGRET e SPSS. As análises incluíram tabulações simples para determinação de prevalência das condições investigadas e regressão logística para avaliar o efeito conjunto das variáveis independentes sobre cada uma das variáveis dependentes. A população que freqüenta a emergência do HNSC é composta de jovens, predominantemente do sexo feminino, mora em Porto Alegre (especialmente, no bairro Sarandi) e na Grande Porto Alegre (especialmente, Alvorada), desloca-se preferencialmente de ônibus até o serviço de emergência, vem acompanhada, na maioria das vezes, de algum familiar, e a maioria decide consultar por iniciativa própria ou por indicação de algum familiar. Os homens internam com maior freqüência. Os serviços de atenção primária representaram 23% do atendimento habitual dos pacientes. As consultas foram definidas pelos emergencistas como de emergência em 15% dos casos, de urgência em 46%, e programáveis em 39% poderiam ser programadas. A prevalência de hipertensão foi 19%; de angina, 13%; de alcoolismo, 16%; de problema psiquiátrico menor, 32% entre os homens e 51% entre as mulheres (p< 0,0001). Como desfecho da consulta, 73% dos pacientes foram encaminhados para o domicílio ou para um serviço especializado, 10% foram para sala de observação e para apenas 5% foi indicada a internação. A maioria dos pacientes referiram estar satisfeitos com o atendimento. Os que consultaram no final de semana apresentaram, em média, um tempo menor de sintomas até decidir consultar, um menor tempo de deslocamento até o serviço de emergência, maior satisfação, média de idade maior, maior proporção de moradores de Porto Alegre e foram levados de carro até a emergência mais do que aqueles que consultaram durante a semana. O modelo de regressão logística identificou as variáveis independentes determinantes de ter um médico definido: consulta habitual em atenção primária em saúde (RC=3,22 IC95%=2,04-5,09), consulta definida como emergência ou urgência (RC=2,46 IC95%=1,55-3,92) e afastamento do trabalho (RC=1,59 IC95%= 1,03-2,45). Este resultado demonstra que o paciente que habitualmente consulta em serviços de atenção primária tem mais probabilidade para ter a continuidade no atendimento. A consulta ser de emergência ou de urgência apresentou associação significativa com as seguintes variáveis independentes, após ser colocada num modelo de regressão logística: pacientes internados ou em observação (RC=5,80 IC95%=3,33-10,17), costume de consultar com o mesmo médico (RC=2,98 IC95%=1,84-4,80) e ida de carro até a emergência (RC=2,67 IC95%=1,75-4,05). A variável hábito de consultar em serviço de atenção primária deixou de ficar estatisticamente significativa ao ser colocada no modelo de regressão logística. Este resultado revela que pacientes com médico definido têm três vezes mais chances de consultar por um problema de emergência no serviço de emergência do que aqueles que não têm um médico definido. Assim, uma estratégia para reduzir a ocorrência de consultas não urgentes em serviços de emergência é o paciente ter tal vínculo. No entanto, aqueles pacientes que referiram o posto de saúde como local onde habitualmente consultam não evitam, necessariamente, a utilização de um serviço de emergência por motivo considerado como programável. É necessário otimizar o atendimento de pacientes com problemas não urgentes que chegam à emergência através de estratégias no nível de atenção primária – especialmente possibilitando o atendimento médico continuado -, onde uma abordagem integral com ênfase na prevenção garanta um atendimento de melhor qualidade e custo menor.

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Convex combinations of long memory estimates using the same data observed at different sampling rates can decrease the standard deviation of the estimates, at the cost of inducing a slight bias. The convex combination of such estimates requires a preliminary correction for the bias observed at lower sampling rates, reported by Souza and Smith (2002). Through Monte Carlo simulations, we investigate the bias and the standard deviation of the combined estimates, as well as the root mean squared error (RMSE), which takes both into account. While comparing the results of standard methods and their combined versions, the latter achieve lower RMSE, for the two semi-parametric estimators under study (by about 30% on average for ARFIMA(0,d,0) series).

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A inserção do princípio da eficiência na Constituição Federal de 1988 vem provocando a necessidade de melhor atuação e aperfeiçoamento dos Tribunais de Contas no Brasil, visando ao melhor atendimento das demandas da sociedade. O desenvolvimento de ações para o acompanhamento dessas demandas é de suma importância para o fortalecimento dos órgãos de controle externo, cuja credibilidade depende da eficiência e da eficácia com que respondem às demandas sociais. A presente pesquisa analisou até que ponto o uso de tecnologia de informação emprestou eficiência ao atendimento de demandas da sociedade pelo Tribunal de Contas do Estado de Pernambuco. Quanto à metodologia, a pesquisa foi descritiva, de campo e estudo de caso. O universo foi composto pelos servidores do Tribunal de Contas do Estado de Pernambuco, sendo utilizadas duas populações amostrais. Os dados foram coletados por entrevistas e questionário e tratados com abordagem qualitativa e estatística descritiva. Verificou-se que, apesar dos avanços já alcançados na gestão administrativa do órgão, inclusive com a disseminação do uso de tecnologia de informação, há uma carência de aprimoramento no recebimento e no acompanhamento das demandas recebidas. Identificou-se que a disponibilização de informações gerenciais sobre essas demandas repercutirá na eficiência administrativa da instituição. O estudo sugere um conjunto de ações que podem ser implantadas e desenvolvidas no Tribunal de Contas do Estado de Pernambuco, com o objetivo de elevar a sua eficiência administrativa no atendimento às demandas sociais. Para identificação de um referencial de boas práticas, visando à implementação de mudanças, foi utilizada a tecnologia de gestão benchmarking. A unidade que serviu como parâmetro foi a Ouvidoria do próprio Tribunal, com realização de benchmarking interno e de processo

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Asset allocation decisions and value at risk calculations rely strongly on volatility estimates. Volatility measures such as rolling window, EWMA, GARCH and stochastic volatility are used in practice. GARCH and EWMA type models that incorporate the dynamic structure of volatility and are capable of forecasting future behavior of risk should perform better than constant, rolling window volatility models. For the same asset the model that is the ‘best’ according to some criterion can change from period to period. We use the reality check test∗ to verify if one model out-performs others over a class of re-sampled time-series data. The test is based on re-sampling the data using stationary bootstrapping. For each re-sample we check the ‘best’ model according to two criteria and analyze the distribution of the performance statistics. We compare constant volatility, EWMA and GARCH models using a quadratic utility function and a risk management measurement as comparison criteria. No model consistently out-performs the benchmark.

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We consider a class of sampling-based decomposition methods to solve risk-averse multistage stochastic convex programs. We prove a formula for the computation of the cuts necessary to build the outer linearizations of the recourse functions. This formula can be used to obtain an efficient implementation of Stochastic Dual Dynamic Programming applied to convex nonlinear problems. We prove the almost sure convergence of these decomposition methods when the relatively complete recourse assumption holds. We also prove the almost sure convergence of these algorithms when applied to risk-averse multistage stochastic linear programs that do not satisfy the relatively complete recourse assumption. The analysis is first done assuming the underlying stochastic process is interstage independent and discrete, with a finite set of possible realizations at each stage. We then indicate two ways of extending the methods and convergence analysis to the case when the process is interstage dependent.

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The current study presents the characteristics of self-efficacy of students of Administration course, who work and do not work. The study was conducted through a field research, descriptive, addressed quantitatively using statistical procedures. Was studied a population composed of 394 students distributed in three Higher Education Institutions, in the metropolitan region of Belém, in the State of Pará. The sampling was not probabilistic by accessibility, with a sample of 254 subjects. The instrument for data collection was a questionnaire composed of a set of questions divided into three sections: the first related to sociodemographic data, the second section was built to identify the work situation of the respondent and the third section was built with issues related to General Perceived Self-Efficacy Scale proposed by Schwarzer and Jerusalem (1999). Sociodemographic data were processed using methods of descriptive statistics. This procedure allowed characterizing the subjects of the sample. To identify the work situation, the analysis of frequency and percentage was used, which allowed to classify in percentage, the respondents who worked and those that did not work, and the data related to the scale of self-efficacy were processed quantitatively by the method of multivariate statistics using the software of program Statistical Package for Social Sciences for Windows - SPSS, version 17 from the process of Exploratory Factor Analysis. This procedure allowed characterizing the students who worked and the students who did not worked. The results were discussed based on Social Cognitive Theory from the construct of self-efficacy of Albert Bandura (1977). The study results showed a young sample, composed the majority of single women with work experience, and indicated that the characteristics of self-efficacy of students who work and students who do not work are different. The self-efficacy beliefs of students who do not work are based on psychological expectations, whereas the students who work demonstrated that their efficacy beliefs are sustained by previous experiences. A student who does not work proved to be reliant in their abilities to achieve a successful performance in their activities, believing it to be easy to achieve your goals and to face difficult situations at work, simply by invest a necessary effort and trust in their abilities. One who has experience working proved to be reliant in their abilities to conduct courses of action, although know that it is not easy to achieve your goals, and in unexpected situations showed its ability to solve difficult problems

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This descriptive study aimed to investigate the relationship between expression of immunological (TCD4 +) and virological (viral load) parameters, lipodystrophy syndrome and lifestyle variables of people living with HIV who underwent a program of physicalexercise. Initially, the sample was composed by 17 persons, recorded at the Department of Giselda Trigueiro Hospital Care (GTH), Natal-RN . With the passing of the stages of intervention (physical training program- PTP) the number of participants has changed (17, 9, 8 and 7) as the training phases (I, II, III and IV). Data collected were on total cholesterol, High Density Lipoprotein (HDL) and triglycerides. The % fat (% F), body mass index (BMI), waist-hip ratio (WHR), lean mass (LM), central fat (BF), total (TF) and peripheral (PF), weight and height were used to measure the morphological parameters. For control of variables (TCD4 +, viral load, Triglycerides, Cholesterol, HDL), the information contained in the blood tests every four months were investigated. After Phase I and II, it was used a structured interview. Then sampling was carried out considering the pre-and post-tests 1, 2, 3 and 4 (after 16, 32, 48 and 64 weeks of training, respectively). Daily, the intensity of the work was checked by the scale of perceived exertion for exercises adapted to resistance34. Procedures used were descriptive statistics (dispersion, absolute and relative frequencies, means, standard deviations and minimum and maximum values) as well as Spearman linear correlation adopting a significance level of p ≤ 0.05. Positive changes were observed for TCD4 + and viral load in all phases of the PTP. For the morphological components, the loss of central subcutaneous fat (CSF) and total subcutaneous fat (TSF) for both sexes and the decrease in % BF among women were the most dramatic results after the training phase I. For men, results were more significant to % F and LM in Phases I and II and peripheral subcutaneous fat (PSF) declined in all phases of the exercise. As for women, results were more expressive for % F and TM in the phases I and II and the PSF decreased in all phases of the exercise. Whereas for women, the waist/hip ratio (WCQ) and 0% F decreased and showed a positive association with triglycerides (WHR r * 0.82, p 0.042, r 0.88 TSF *, p 0.019 and r 1.00 ** CSF, p <0.001) and among men with limb subcutaneous fat (LSF)* r 0.65, p 0.029). The PTP provided improvement in the health, self-esteem and quality of life, proving to be a possible strategy to positively influence the expression of immunological parameters (TCD4 +) and virological (viral load) and morphological components of people living with HIV causing no deleterious effects in these parameters

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this work - which is characterized analyze the search for symptomatic tuberculosis in practice and perspective of the Community Health Agent (ACS) in the districts of Natal. Methods: This is a cross-sectional study. The study population was 646 professionals, and conducted a probabilistic random sampling, stratified by districts. The data were collected from one instrument to collect data based on Primary Care Assesment Toll (PCAT) and analyzed by descriptive statistics. The sample consisted of ACS was 87% female. Among the study participants 58% completed high school and 120 months of exercise training (95% CI 111.9 to 129.5) on average. 90% were USF. The average follow-up of cases found were 2 cases of TB since the beginning of the career of the ACS and the last three years the average is presented in a case accompanied. The ACS received satisfactory ratings on the bond of trust with the user, so as access to homes in the community. The ACS reported for denying the fear of being positive result was the biggest reason for not performing the sputum. All units have a professional that responds to the Tuberculosis Control Program. Regarding the structural capacity of primary care settings for the diagnosis of TB, we observed satisfactory levels in different districts of pots for sputum collection, however, a point that deserves attention from managers is lack of materials for packaging sputum. Fear of positive result was one of the reasons for the refusal of sputum collection, followed by alcoholism. With regard to TB suspects, all responded that ACS always suspect when the user has TB coughs, but in all districts were noticed at low delivery of requests for applications for smear. BSR in TB control, is characterized in practice as a complex action goes beyond technical expertise and contact with the family that breaks with the Cartesian. The BSR is part of the ACS can perform them from the daily visits. We conclude that the ACS is difficult to achieve. This practice should not be the privilege of this actor, but the entire team of primary care. We must rethink the practices of TB care, seeing the health surveillance while aegis of the working process of primary care teams for early diagnosis and thereby reduce TB in communities

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The nurses in the hemodialysis has an important role in the nursing process implementation, in the context of a theoretical referential. Among the nursing theories, highlights the Roy´s adaptations model, who considers a person as an holistic adaptive system that aims to adapt customers to different living conditions. Thus, it is believed that the Roy´s nursing process will guide nursing care to patients on dialysis. Therefore, the study aimed to analyze the nursing diagnosis present in patients with chronic kidney disease on hemodialysis based on the theoretical model of Roy and NANDA-International. Descriptive and cros-sectional study, performed at a dialysis center in a city in northeastern Brazil. Sample of 178 patients and consecutive sampling by convenience. Data collection ocurred from October/2011 until February/2012, through interview and physical examination forms. Data analysis was initiated by clinical reasoning, diagnosis judgment and similarity relation. Then, the data were entered into SPSS program, 16.0 version, generating descriptive statistics. The project was approved by the Ethics Research Committee (protocol nº 115/11) with a Presentation Certificate for Ethics Appreciation (in 0139.0.051.000-111) and was funded by the Universal edict MCT / CNPq 14/2010. The results revealed that most patients were male (52.2%), married (62.9%) and residents in the Natal´s metropolitan region (54.5%). The mean age was 46.6 years and the years of study, 8,5. Regarding nursing diagnosis obtained an average of 6.6, especially: Risk of Infection (100%), excessive fluid volume (99.4%) and hypothermia (61.8%). On the other hand the adaptive problems average was 6.4, and the most common: intracellular fluid retention (99.4%); Hyperkalemia (64.6%); Hypothermia (61.8%) and edema (53.9%). Were established 20 similarity relations between the NANDA-International nursing diagnosis and adaptive problems of Roy, namely: risk of falls / injury risk and potential for injury, impaired physical mobility and walking mobility and / or restricted coordination, dressing self-care deficit and loss of self-care ability; hypothermia and hypothermia; impaired skin integrity and impaired skin integrity; excessive fluid volume and intracellular fluid retention / Hyperkalemia / Hypocalcemia / edema; imbalanced nutrition: less than body requirements and Nutrition less than the body's needs; constipation and constipation, acute pain and acute pain, chronic pain and chronic pain, sensorial perception disturbed: visual, tactile and auditory disabilities and a primary sense: sight, hearing and tactile; sleep deprivation and insomnia, fatigue and intolerance to activities; ineffective self health and fails in the role; sexual dysfunction and sexual dysfunction; situational low self-esteem and low self-esteem, and diarrhea and diarrhea. We conclude that there is similarity between the typologies and was required a model´s analysis, because they present different ways to establish the nursing diagnosis. Moreover, the nursing process use, under the context of a theory and a classification system, subsidizes the care and contributes to the strengthening of nursing science

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The venous ulcer is an epidemiological problem of high prevalence, causing disability and dependence. Assess the tissue impairment level of patients with venous lesions, within a nursing referential, is relevant for the implementation of a directed assistance to specific clientele. Thus, this work aims to characterize the health status regarding the integrity the lower limbs skin of patients with venous ulcers, according to the of tissue integrity outcome indicators from the Nursing Outcomes Classification. A cross-sectional study conducted in a university hospital in Natal - Rio Grande do Norte. The sample consisted of 50 participants, selected through consecutive sampling. Data collection occurred through a interview and physical examination form and a operational definitions tool for indicators of the nursing Tissue Integrity outcome directed to patients with venous ulcer, applied from February to June 2012. Data analysis was done by descriptive statistics and nonparametric tests (Spearman, Kruskal-Wallis and Mann-Whitney tests). The project was approved by the Research Ethics Committee with protocol 608/11 and Presentation Certificate to Ethical Consideration No. 0038.0.294.000-11. The results were presented using three scientific articles derivatives of research. It was found that the indicators show moderate impairment, light and not impaired, as the median. The respondents had an average of 59.72 years, 66% female, 50% were retired, 60% with a partner, 44% had arterial hypertension, 26% allergies, 20% diabetes mellitus, 96% were sedentary, 14% drank alcohol and 6% were smokers. There was a statistically significant correlation of low intensity between age and hydration (p=0.032; rs=-0.304) and skin desquamation (p=0.026; rs=-0.316), family income and necrosis (p=0.012; rs=-0.353); Ankle Brachial Index and tissue perfusion (p=0,044; rs=-0,329); Diabetes Mellitus and texture (p=0.015) and tissue perfusion (p=0.026); allergy and texture (p=0.034), physical activity and hydration (p=0.034), smoking and thickness (p=0.018), and alcohol consumption and exudate (p=0.045). We conclude that the patients had light to moderate impairment, indicating a good state of health on the integrity of the skin of the lower limbs, according to the indicators of the outcome of tissue integrity Classification Nursing Outcomes valued in the present study. It is believed that the evaluation of impairment tissue using a self-nursing system and its relation with socioeconomic, clinical and risk factors are unique tools in the care planning and in the wound healing

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Foliar diagnosis is a method for assessing the nutritional status of agricultural crops, which helps in the understanding of soil fertility and rationalized application of fertilizers taking into account economic and environmental criteria. The study aimed to use the landrelief as criteria to assist in interpreting the spatial variability of nutrient content of the citrus leaf. The leaves were collected at regular intervals of 50 m, totaling 332 sampling points. Data were analyzed by descriptive statistics, geostatistics and induction of decision tree. With the aid of digital elevation model (MDE) and the profile planaltimetric, the area was divided into three different landrelief and sub-strands. The highest values for nutrients from the leaves of citrus were observed at the top (concave area) segments on a half-slope and lower slope. The nutrients from the citrus leaves showed high values of correlation (above 0.5) with the altitude of the study area. The technique of geostatistics and the induction of decision tree show that the relief is the variable with the greatest potential to interpret the maps of spatial variability of nutrients from the citrus leaves.