924 resultados para chi-squared distribution
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Objetivo: Associar fatores de risco para doenças crônicas não transmissíveis (DCNT) com variáveis sociodemográficas de servidores de uma instituição pública de ensino superior. Métodos: Estudo transversal, realizado no período de 2012 a 2013. Utilizou-se um questionário com variáveis sociodemográficas, fatores de risco para DCNT e aferição de peso e estatura. Classificou-se o estado nutricional de acordo com o índice de massa corporal. Analisaram-se os dados pelos programas Epi-Info 3.2.1 e Bioestat 5.0. As associações foram verificadas pelos testes qui-quadrado de Yates, de tendência e exato de Fisher (p≤0,05). Resultados: Participaram 225 servidores, maioria de mulheres (64,4%), na faixa etária entre 45-54 anos (37,3%) e escolaridade superior a 12 anos de estudo (85,8%). O sexo associou-se ao excesso de peso (p=0,034), consumo diário de leite integral (p=0,023), consumo insuficiente de frutas, legumes e verduras - FLV (p=0,020) e consumo insuficiente de feijão (p=0,000), sendo mais frequentes entre mulheres. Entre os homens, foi mais frequente o consumo excessivo de bebida alcoólica (p=0,000). O excesso de peso associou-se à faixa etária (p=0,008). O hábito de fumar (p=0,004) e o consumo diário de leite integral (p=0,016) apresentaram associação com a escolaridade. Conclusão: Encontrou-se elevada prevalência de fatores de risco para doenças crônicas não transmissíveis na amostra estudada, com associação para sexo, faixa etária e escolaridade. O excesso de peso apresentou maior ocorrência nas mulheres e nas idades acima de 45 anos, hábitos alimentares inadequados no sexo feminino, maior ingestão de bebida alcoólica no masculino e hábito de fumar nos indivíduos com maior escolaridade.
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Objetivo: Caracterizar o perfil de religiosidade e estilo de vida de uma população adulta e analisar a associação entre essas variáveis. Métodos: Pesquisa descritiva, transversal e quantitativa, realizada com participantes (n=206) de duas Feiras de Saúde na cidade de São Paulo, em 20/10/2013 e 04/05/2014. Aplicaram-se dois instrumentos, o Duke University Religion Index (DUREL, subdividido nas dimensões Religiosidade Organizacional, Não Organizacional e Intrínseca) e o Estilo de Vida FANTÁSTICO. Realizaram-se os testes Rho de Spearman para associação das variáveis “estilo de vida” e “religiosidade”, e Qui- Quadrado para análise bivariada entre sexo e religiosidade. Resultados: Encontrou-se perfil de religiosidade predominantemente bom nas três dimensões, com destaque para a Religiosidade Intrínseca, que alcançou 83,5% (n=167) nos três quesitos. Quanto ao estilo de vida (FANTÁSTICO), obteve-se a classificação de: 26,6% (n=34) “Bom”, 48,4% (n=62) “Muito Bom” e 12,5% (n=16) “Excelente”. Das 125 análises bivariadas, 13 (11,3%) apresentaram correlação fraca (ρ< 0,30), porém significativa (p<0,05). Nas associações do Qui-Quadrado, a religiosidade se relacionou às dimensões do estilo de vida quanto ao uso de álcool e drogas, alimentação equilibrada e saúde mental. Conclusão: A religiosidade na população estudada, considerando-se as três dimensões analisadas, caracterizou-se como “boa” e “muito boa”; e o estilo de vida, segundo escore total do questionário FANTÁSTICO, pôde ser considerado saudável. Apesar de fraca, confirmou-se associação entre a religiosidade e o estilo de vida.
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Objective: To estimate the prevalence and factors associated with the performance of mammography and pap smear test in women from the city of Maringá, Paraná. Methods: Population-based cross-sectional study conducted with 345 women aged over 20 years in the period from March 2011 to April 2012. An interview was carried out using a questionnaire proposed by the Ministry of Health, which addressed sociodemographic characteristics, risk factors for chronic noncommunicable diseases and issues related to mammographic and pap screening. Data were analyzed using bivariate analysis, crude analysis with odds ratio (OR) and chi-squared test using Epi Info 3.5.1 program; multivariate analysis using logistic regression was performed using the software Statistica 7.1, with a significance level of 5% and a confidence interval of 95%. Results: The mean age of the women was 52.19 (±5.27) years. The majority (56.5%) had from 0 to 8 years of education. Additionally, 84.6% (n=266) of the women underwent pap smear and 74.3% (n=169) underwent mammography. The lower performance of pap smear test was associated with women with 9-11 years of education (p=0.01), and the lower performance of mammography was associated with women without private health insurance (p<0.01). Conclusion: The coverage of mammography and pap smear test was satisfactory among the women from Maringá, Paraná. Low education level and women who depended on the public health system presented lower performance of mammography.
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Objective: Little is known about the extent of mental, neurological and substance-use (MNS) disorders re-hospitalization in South Africa. We examined the extent of one-year MNS re-hospitalization (MNS-R) in a rural South African primary health care facility (PHCF). Methods: We conducted a retrospective analysis of hospital administrative data from 10,525 adults discharged from a rural PHCF in KwaZulu-Natal Province, South Africa. Chi-squared tests were utilized to describe MNS-R within one year of an index hospital admission in individuals with MNS, with a sub-analysis also being conducted to describe schizophrenia re-hospitalization (S-R). Results: The prevalence of MNS and schizophrenia recorded at an index hospitalization was 5% and 1%, respectively. A total of 44/67 (66%) individuals with a diagnosis of MNS at the index hospitalization were classified as having MNS-R during oneyear follow-up period. Half of those diagnosed with schizophrenia at the index hospitalization (6/12 patients) were classified as having S-R during one-year follow-up period. There was a significant association between re-hospitalization outcomes (MNS-R and S-R) and MNS (p<0.01) or schizophrenia diagnosis (p<0.01) at index baseline hospitalization. Conclusion: The extent of MNS-R and S-R remains relatively high in rural South Africa, and needs further health systems strengthening to prevent revolving door occurrences.
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Antecedentes De las complicaciones crónicas de la diabetes, la más destacada es la neuropatía. Esta produce disminución en la calidad de vida, ya que conlleva al paciente a tener dificultades como: dolor, parestesias, ulceraciones, e incluso alteración en la deambulación. Objetivos Determinar la prevalencia de neuropatía simétrica distal en pacientes que integran los clubes de diabéticos del distrito 01D01 y su relación con sus estilos de vida. Materiales y Métodos Es un estudio transversal con una muestra de 162 pacientes, seleccionados al azar, sobre la base del 30% de prevalencia de neuropatía, con un nivel de confianza del 95% y error de inferencia del 5%. Fueron aplicados dos cuestionarios avalados (NSS+NDS). Para el análisis, usamos el programa SPSS 15. Las variables demográficas, se analizaron por estadística descriptiva. La relación entre las variables dependientes y variables independientes se evaluó a través de la razón de prevalencia, con un intervalo de confianza del 95%, chi cuadrado y valor de p. Resultados La prevalencia de neuropatía diabética es del 54.9%, en hombres 73.7% y en mujeres 49.2%. Los factores protectores son: Recibir indicaciones sobre cuidado de los pies con 66.7% (RP 2 y valor de p 0.033), y el buen control de glucosa en sangre con el 95.9% (RP 2.3 y valor de p 0.001). Conclusiones La neuropatía diabética simétrica distal se presenta más en hombres que en mujeres. Además se encontró que el buen control de glucosa en sangre y recibir indicaciones sobre cuidado de los pies, disminuyen el riesgo de neuropatía.
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Objetivo: El objetivo de este estudio fue determinar la prevalencia de los trastornos músculoesqueléticos y la asociación con factores sociodemográficos y hábitos de vida en trabajadores de las áreas administrativa y operativa de dos empresas de servicio de la ciudad de Bogotá 2015. Materiales y Métodos: Se realizó un estudio de corte transversal, con información secundaria, procedente de bases de datos suministrada por las dos empresas con 696 registros de trabajadores de servicios generales, y 943 registros de trabajadores del área administrativa, para un total de 1639 registros, en los cuales se evaluó la presencia de síntomas osteomusculares clasificados por segmento. Adicionalmente se contaba con información de características sociodemográficas y estilos de vida de estos trabajadores. Se obtuvieron las distribuciones de frecuencias absolutas y relativas para las variables cualitativas, y las medidas de tendencia central y de dispersión para las variables cuantitativas. Para establecer la asociación entre factores sociodemográficos con las variables dependientes se utilizó la prueba chi2 de asociación. Resultados: La prevalencia de molestia o dolor en los diferentes segmentos corporales fue de 21.5 % (n = 203) en cuello para la población administrativa y de 17.5% (n = 148) en mano y muñeca derecha para la población de servicios generales. Vale la pena aclarar que el diagnóstico médico más frecuente referido por la población en estudio fue traumas en musculo, bursa tendón y/o ligamento con 10.5% en la población administrativa y con el 12.4% en la población de servicios generales. De las asociaciones significativas entre diagnósticos presentes y hábitos de vida y sueño se encontró que sueño no reparador se asoció significativamente con enfermedad general de músculos y huesos (p = 0.001), enfermedad o trauma activo de tejidos blandos (p = 0,000) y antecedente o enfermedad actual de columna vertebral (p = 0,000). De manera similar, el consumo de medicamentos para conciliar el sueño se asoció con enfermedad de tejidos blandos (p = 0,000) y enfermedad actual de columna vertebral (p = 0,000). El consumo de café (p = 0.001) y el sedentarismo (p = 0.031) están asociados con la enfermedad general de músculos y huesos. Conclusiones: Los TME son un factor de alta prevalencia en la población trabajadora de Colombia, y como se demostró en este estudio, afectan a la población de las empresas de servicio. Se evidencia cada vez más que los segmentos corporales más afectados en la población administrativa, son cabeza y cuello, debido a las posturas mantenidas por largos periodos de tiempo, y en la población de servicios se encontró molestia y dolor en muñecas y manos debido a los movimientos repetitivos que deben de realizar durante la jornada laboral. Se hace necesario profundizar más en la asociación significativa de los trastornos del sueño y la presencia de los TME, ya que se encontró una relación importante entre estos dos.
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Nowadays, World Heritage Sites (WHS) have been facing new challenges, partially due to a different tourism consumption patterns. As it is highlighted in a considerable amount of studies, visits to these sites are almost justified by this prestigious classification and motivations are closely associated with their cultural aspects and quality of the overall environment (among others, Marujo et al, 2012). However, a diversity of tourists’ profiles have been underlined in the literature. Starting from the results obtained in a previous study about cultural tourists’ profile, conducted during the year 2009 in the city of Évora, Portugal, it is our intend to compare the results with a recent survey applied to the visitors of the same city. Recognition of Évora by UNESCO in 1986 as “World Heritage” has fostered not only the preservation of heritage but also the tourist promotion of the town. This study compares and examined tourists’ profile, regarding from the tourists’ expenditure patterns in Évora. A total of 450 surveys were distributed in 2009, and recently, in 2015, the same numbers of surveys were collected. Chi-squared Automatic Interaction Detection (CHAID) was applied to model consumer patterns of domestic and international visitors, based on socio demographic, trip characteristics, length of stay and the degree of satisfaction of pull factors. CHAID allowed find a population classification in groups that able to describe the dependent variable, average daily tourist expenditure. Results revealed different patterns of daily average expenditure amongst the years, 2009 and 2015, even if primarily results not revealed significant variations in socio-demographic and trip characteristics among the visitors’ core profile. Local authorities should be aware of this changing expensive behavior of cultural visitors and should formulate strategies accordingly. Policy and managerial recommendations are discussed.
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This study investigates tourists’ expenditure patterns in the city of Évora, a world heritage site (WHS) classified by UNESCO. The use of chi-squared automatic interaction detection (CHAID) was chosen, allowing the identification of distinct segments based on expenditure patterns. Visitors’ expenditure patterns have proven to be a pertinent element for a broader understanding of visitors’ behaviour at cultural destinations. Visitors’ expenditure patterns were revealed to be increasing within years studied.
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A large number of ridge regression estimators have been proposed and used with little knowledge of their true distributions. Because of this lack of knowledge, these estimators cannot be used to test hypotheses or to form confidence intervals.^ This paper presents a basic technique for deriving the exact distribution functions for a class of generalized ridge estimators. The technique is applied to five prominent generalized ridge estimators. Graphs of the resulting distribution functions are presented. The actual behavior of these estimators is found to be considerably different than the behavior which is generally assumed for ridge estimators.^ This paper also uses the derived distributions to examine the mean squared error properties of the estimators. A technique for developing confidence intervals based on the generalized ridge estimators is also presented. ^
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As a good solution to the shortage and environmental unfriendliness of fossil fuels, plug-in electric vehicles (PEVs) attract much interests of the public. To investigate the problems caused by the integration of numerous PEVs, a lot of research work has been done on the grid impacts of PEVs in aspects including thermal loading, voltage regulation, transformer loss of life, unbalance, losses, and harmonic distortion levels. This paper surveys the-state-of-the-art of the research in this area and outline three possible measures for a power grid company to make full use of PEVs.
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Cyclostationary models for the diagnostic signals measured on faulty rotating machineries have proved to be successful in many laboratory tests and industrial applications. The squared envelope spectrum has been pointed out as the most efficient indicator for the assessment of second order cyclostationary symptoms of damages, which are typical, for instance, of rolling element bearing faults. In an attempt to foster the spread of rotating machinery diagnostics, the current trend in the field is to reach higher levels of automation of the condition monitoring systems. For this purpose, statistical tests for the presence of cyclostationarity have been proposed during the last years. The statistical thresholds proposed in the past for the identification of cyclostationary components have been obtained under the hypothesis of having a white noise signal when the component is healthy. This need, coupled with the non-white nature of the real signals implies the necessity of pre-whitening or filtering the signal in optimal narrow-bands, increasing the complexity of the algorithm and the risk of losing diagnostic information or introducing biases on the result. In this paper, the authors introduce an original analytical derivation of the statistical tests for cyclostationarity in the squared envelope spectrum, dropping the hypothesis of white noise from the beginning. The effect of first order and second order cyclostationary components on the distribution of the squared envelope spectrum will be quantified and the effectiveness of the newly proposed threshold verified, providing a sound theoretical basis and a practical starting point for efficient automated diagnostics of machine components such as rolling element bearings. The analytical results will be verified by means of numerical simulations and by using experimental vibration data of rolling element bearings.
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Background To determine the impact of cataract surgery on vision-related quality of life (VRQOL) and examine the association between objective visual measures and change in VRQOL after surgery among bilateral cataract patients in Ho Chi Minh City, Vietnam. Methods A cohort of older patients with bilateral cataract was assessed one week before and one to three months after first eye or both eye cataract surgery. Visual measures including visual acuity, contrast sensitivity and stereopsis were obtained. Vision-related quality of life was assessed using the NEI VFQ-25. Descriptive analyses and a generalized linear estimating equation (GEE) analysis were undertaken to measure change in VRQOL after surgery. Results Four hundred and thirteen patients were assessed before cataract surgery and 247 completed the follow-up assessment one to three months after first or both eye cataract surgery. Overall, VRQOL significantly improved after cataract surgery (p < 0.001) particularly after both eye surgeries. Binocular contrast sensitivity (p < 0.001) and stereopsis (p < 0.001) were also associated with change in VRQOL after cataract surgery. Visual acuity was not associated with VRQOL. Conclusions Cataract surgery significantly improved VRQOL among bilateral cataract patients in Vietnam. Contrast sensitivity as well as stereopsis, rather than visual acuity significantly affected VRQOL after cataract surgery.
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The World Health Organization identifies road trauma as a major public health issue in every country; most notably among low-to-middle income countries. More than 90% of all road fatalities occur in these countries, although they have only 48% of all registered vehicles [1]. Unprecedented focus has been placed on reducing the global road trauma burden through the United Nations Decade of Action for Road Safety (2011-2020). China is rapidly transitioning from a nation of bicycle riders and pedestrians to one where car ownership and use is increasing. This transition presents important public health, mobility, and safety challenges. Rapid motorisation has resulted in an increased road trauma burden, shouldered disproportionately among the population. Vulnerable road users (bicyclists, pedestrians, and motorcyclists) are of particular concern, representing 70% of all road-related fatalities [1]. Furthermore, those at greatest risk of sustaining a crash-related disability are: male, older, less educated, and earning a lower income [2] and residing in urban areas [3], with higher fatality rates in north-western poorer provinces [3]. Speeding is a key factor in road crashes in China [1, 4] and is one of two risk factors targeted in the Bloomberg Philanthropies-funded Global Road Safety Program operating in two Chinese cities over five year [5] to which the first author has provided expert advice. However, little evidence exists to help understand the factors underpinning speeding behaviour. Previous research conducted by the authors in Beijing and Hangzhou explored personal, social, and legal factors relating to speeding to assist in better understanding the motivations for non-compliance with speed limits. Qualitative and quantitative research findings indicated that speeding is relatively common, including self-reported travel speeds of greater than 30 km/hour above posted speed limits [6], and that the road safety laws and enforcement practices may, in some circumstances, contribute to this [7]. Normative factors were also evident; the role of friends, family members and driving instructors were influential. Additionally, using social networks to attempt to avoid detection and penalty was reported, thereby potentially reinforcing community perceptions that speeding is acceptable [8, 9]. The authors established strong collaborative links with the Chinese Academy of Sciences and Zhejiang Police College to conduct this research. The first author has worked in both institutions for extended time periods and recognises that research must include an understanding of culturally-relevant issues if road safety is to improve in China. Future collaborations to assist in enhancing our understanding of such issues are welcomed. References [1] World Health Organization. (2009). Global status report on road safety: Time for action; Geneva. [2] Chen, H., Du, W., & Li, N. (2013). The socioeconomic inequality in traffic-related disability among Chinese adults: the application of concentration index. Accident Analysis & Prevention, 55(101-106). [3] Wang, S. Y., Li, Y. H., Chi, G. B., Xiao, S. Y., Ozanne-Smith, J., Stevenson, M., & Phillips, M. (2008). Injury-related fatalities in China: an under-recognised public-health problem. The Lancet (British edition), 372(9651), 1765-1773. [4] He, J., King, M. J., Watson, B., Rakotonirainy, A., & Fleiter, J. J. (2013). Speed enforcement in China: National, provincial and city initiatives and their success. Accident Analysis & Prevention, 50, 282-288. [5] Bhalla, K., Li, Q., Duan, L., Wang, Y., Bishai, D., & Hyder, A. A. (2013). The prevalence of speeding and drink driving in two cities in China: a mid project evaluation of ongoing road safety interventions. Injury, 44, 49-56. doi:10.1016/S0020-1383(13)70213-4. [6] Fleiter, J. J., Watson, B., & Lennon, A. (2013). Awareness of risky behaviour among Chinese drivers. Peer-reviewed paper presented at 23rd Canadian Multidisciplinary Road Safety Conference, Montréal, Québec. [7] Fleiter, J. J., Watson, B., Lennon, A., King, M. J., & Shi, K. (2009). Speeding in Australia and China: A comparison of the influence of legal sanctions and enforcement practices on car drivers. Peer-reviewd paper presented at Australasian Road Safety Research Policing Education Conference, Sydney. [8] Fleiter, J. J., Watson, B., Lennon, A., King, M. J., & Shi, K. (2011). Social influences on drivers in China. Journal of the Australasian College of Road Safety, 22(2), 29-36. [9] Fleiter, J. J., Watson, B., Guan, M. Q., Ding, J. Y., & Xu, C. (2013). Characteristics of Chinese Drivers Attending a Mandatory Training Course Following Licence Suspension. Peer-reviewed paper presented at Road Safety on Four Continents, Beijing, China.
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Background Food security exists when all people, at all times, have physical, economic and socially acceptable access to safe, sufficient, and adequately nutritious food in order to meet their dietary needs for an active and healthy life. For high income countries and those experiencing the nutrition transition, food security is not only about the quantity of available food but also the nutritional quality as related to over- and under-nutrition. Vietnam is currently undergoing this nutrition transition, and as a result the relationship between food insecurity, socio-demographic factors and weight status is complex. The primary objective of this study was to therefore measure the prevalence of household food insecurity in a disadvantaged urban district in Ho Chi Minh City (HCMC) in Vietnam using a more comprehensive tool. This study also aims to examine the relationships between food insecurity and socio-demographic factors, weight status, and food intakes. Methods A cross-sectional study was conducted using multi-stage sampling. Adults who were mainly responsible for cooking were interviewed in 250 households. Data was collected on socioeconomic and demographic factors using previously validated tools. Food security was assessed using the Latin American and Caribbean Household Food Security Scale (ELCSA) tool and households were categorized as food secure or mildly, moderately or severely food insecure. Questions regarding food intake were based on routinely used and validated questions in HCMC, weight status was self-reported. Results Cronbach’s alpha coefficient was 0.87, showing the ELCSA had a good internal reliability. Approximately 34.4% of households were food insecure. Food insecurity was inversely related to total household income (OR = 0.09, 95% CI = 0.04 - 0.22) and fruit intakes (OR = 2.2, 95% CI 1.31 - 4.22). There was no association between weight and food security status. Conclusions Despite rapid industrialization and modernization, food insecurity remains an important public health issue in large urban areas of HCMC, suggesting that strategies to address food insecurity should be implemented in urban settings, and not just rural locations. Fruit consumption among food insecure households may be compromised because of financial difficulties, which may lead to poorer health outcomes particularly related to non-communicable disease prevention and management.
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The biomass and species composition of tropical phytoplankton in Albatross Bay, Gulf of Carpentaria, northern Australia, were examined monthly for 6 yr (1986 to 1992). Chlorophyll a (chl a) concentrations were highest (2 to 5.7 mu g l(-1)) in the wet season at inshore sites, usually coinciding with low salinities (30 to 33 ppt) and high temperatures (29 to 32 degrees C). At the offshore sites chi a concentrations were lower (0.2 to 2 mu g l(-1)) and did not vary seasonally. Nitrate and phosphate concentrations were generally low (0 to 3.68 mu M and 0.09 to 3 mu M for nitrate and phosphate respectively), whereas silicate was present in concentrations in the range 0.19 to 13 mu M. The phytoplankton community was dominated by diatoms, particularly at the inshore sites, as determined by a combination of microscopic and high-performance liquid chromatography (HPLC) pigment analyses. At the offshore sites the proportion of green flagellates increased. The cyanobacterium genus Trichodesmium and the diatom genera Chaetoceros, Rhizosolenia, Bacteriastrum and Thalassionema dominated the phytoplankton caught in 37 mu m mesh nets; however, in contrast to many other coastal areas studied worldwide there was no distinct species succession of the diatoms and only Trichodesmium showed seasonal changes in abundance. This reflects a stable phytoplankton community in waters without pulses of physical and chemical disturbances. These results are discussed in the context of the commercial prawn fishery in the Gulf of Carpentaria and the possible effect of phytoplankton on prawn larval growth and survival.