935 resultados para multistage sampling


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Maize (Zea mays) and guinea corn (Sorghum bicolor) are major food items in Plateau state, Nigeria. A multistage sampling technique was used to select the markets and store/warehouses used for this study; sample collection employed a simple random sampling method from different sampling points within designated areas. A total of 18 representative samples were collected and analyzed for the following mycotoxins: aflatoxins (Aflatoxin B1 - AFB1, Aflatoxin B2 - AFB2, Aflatoxin G1 - AFG1 and Aflatoxin G2 - AFG2), fumonisins (Fumonisin B1 - FB1 and Fumonisin B2 - FB2 ) and cyclopiazonic acid (CPA). Out of 12 samples analyzed for Aflatoxins, AFB1 was detected in 5, AFB2 in 1, AFG1 in 1 and AFG2 in 6 samples respectively. The highest concentration of AFB1 and AFG2 were found in maize samples from Pankshin market. Only maize samples from Mangu market were contaminated with AFB2 and also harboured the lowest concentration of AFG2. AFG1 contamination occurred in only guinea corn from Shendam market. and FB1 was detected in all 18 samples analyzed. The mycotoxin CPA was not detected in any of the samples. Aflatoxins levels in analyzed samples were regarded as safe based on Nigerian and European Union maximum permissible levels of 4g/kg. With the exception of two samples, FB1 levels in analyzed maize samples were within European Union maximum permissible levels of 1,000 to 3000g/kg. The health and food safety implications of these results for the human and animal population are further discussed.

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ABSTRACT Objective The use of benzodiazepines (BZD) and associated factors in the elderly of Dourados, MS, Brazil was investigated. Methods This is a cross-sectional population-based study using a multistage sampling design. Participants were 1,022 individuals aged ≥ 60 years. Measurements socioeconomic status, schooling, demographic aspects, marital status, physical activity, hospitalizations, self-rated health, use of alcohol beverages and smoking were assessed by standard questionnaire. The drugs used were obtained by checking the prescription or package and classified according to the Anatomical Therapeutic Chemical Index. Chi-square test, Chi-square for linear tendency, Fisher's exact test and Poisson regression were used to assess association between variables. Results The prevalence of use of BZD was 6.5% (CI95%: 5.1-8.2%). The oldest group (PR: 1.60 for 70-79 years and PR: 1.79 for ≥ 80 years), non-use of alcohol (PR: 4.14) and use of antidepressants (PR: 8.73) were the statistically associated characteristics. Conclusions The prevalence of use of BZD in the study population was low, similar to findings of more recent Brazilian studies and lower than those obtained in international studies. The prevalence of use of BZD increased with aging and use of antidepressants.

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Este artigo analisa a prevalência da utilização de medicamentos segundo variáveis demográficas, socioeconômicas e de comportamentos relacionados à saúde, identificando fatores associados ao uso por meio de estudo transversal de base populacional, com 941 pessoas de 18 anos ou mais residentes em Campinas, São Paulo, Brasil. A amostragem foi realizada em múltiplos estágios, estratificada e por conglomerados. Utilizou-se o teste qui-quadrado, foram estimadas as razões de prevalência ajustadas por sexo e idade e os respectivos IC95%. Desenvolveu-se modelo de regressão múltipla de Poisson ficando associados ao uso: sexo feminino, idade de 40 anos e mais, morbidade referida nos últimos 15 dias e número de doenças crônicas. Os medicamentos mais consumidos foram para os sistemas cardiovascular e nervoso, e os fitoterápicos. A prevalência de uso de medicamentos em Campinas encontrou-se inferior à maioria dos estudos. Por meio de inquéritos de saúde locais espera-se conhecer o perfil de uso dos medicamentos pela população e garantir intervenções mais direcionadas para a Política de Assistência Farmacêutica.

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This article reports on smoking prevalence and associated factors in the elderly, based on a population-based cross-sectional study with multistage sampling including 1,954 individuals 60 years or older living in four areas of Sao Paulo State, Brazil. Overall smoking prevalence was 12.2%, and higher rates were associated with male gender, age 60-69 years, not belonging to an Evangelical church, lower income, low body weight, lack of leisure-time physical activity, depression/anxiety, and hypertension. There was a high prevalence of smokers among individuals with a history of stroke, cancer, and chronic obstructive pulmonary disease. The results point to the need for effective interventions in healthcare services to promote smoking cessation among the elderly, since many are unable to stop on their own, even when they have tobacco-related illnesses. Special attention should be paid to individuals that depend on the National Health System, since smoking prevalence is higher in underprivileged socioeconomic groups.

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This study examined the relationship between medical advice to engage in physical activity with type of demand required by physical activity and demographic variables. A cross-sectional study was developed, featuring a questionnaire on physicians? advice, and type of demand. The questionnaire was completed by a probability and nationwide sample of older adults in Spain ( n = 933, M = 74.1, range 65?93), randomly selected using multistage sampling. More physically active older adults have, more often than the less active, received physicians? advice to engage in physical activity. There is a signifi cant relationship between medical advice and type of demand ( p menor que .01) and age ( p menor que .05). However, no relationship was found between physician medical advice and gender, social class, or income. Physicians can effectively promote physical activity among sedentary older adults through appropriate advice. Consequently, health authorities should promote physicians' advising older patients to pursue physical activity.

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Disability, employment, and employment restrictions among persons with ICD-10 anxiety disorders were investigated at a population level in comparison to persons without disability or long-term health conditions. Data were provided by the Australian Bureau of Statistics (ABS) collected in a 1998 national survey. Multistage sampling obtained a probability sample of 37,580 individuals in the household component of the survey. Trained lay interviewers using ICD-10 computer-assisted interviews identified household residents with anxiety disorders. Details of employment restrictions are reported and discussed. The four most commonly reported restrictions were: restricted in the type of job (24.0%); need for a support person (23.3%); difficulty changing jobs (18.6%); and restricted in the number of hours (15.4%). The nature and extent of employment restrictions characterizing persons with anxiety disorders indicates a need for strengthened disability and health condition screening at application for Government income support and at gateways to public funded vocational assistance. (c) 2004 Elsevier Inc. All rights reserved.

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In this study cross-section data was used to analyze the effect of farmers’ demographic, socioeconomic and institutional setting, market access and physical attributes on the probability and intensity of tissue culture banana (TCB) adoption. The study was carried out between July 2011 and November 2011. Both descriptive (mean, variance, promotions) and regression analysis were used in the analysis. A double hurdle regression model was fitted on the data. Using multistage sampling technique, four counties and eight sub-locations were randomly selected. Using random sampling technique, three hundred and thirty farmers were selected from a list of banana households in the selected sub-locations. The adoption level of tissue culture banana (TCB) was about 32%. The results also revealed that the likelihood of TCB adoption was significantly influenced by: availability of TCB planting material, proportion of banana income to the total farm income, per capita household expenditure and the location of the farmer in Kisii County; while those that significantly influenced the intensity of TCB adoption were: occupation of farmers, family size, labour source, farm size, soil fertility, availability/access of TCB plantlets to farmers, distance to banana market, use of manure in planting banana, access to agricultural extension services and index of TCB/non-TCB banana cultivar attributes which were scored by farmers. Compared to West Pokot County, farmers located in Bungoma County are more significantly and likely to adopt TCB technology. Therefore, the results of the study suggest that the probability of adoption and intensity of the use of TCB should be enhanced. This can be done by taking cognizance of these variables in order to meet the priority needs of the smallholder farmers who were the target group. This would lead to alleviating banana shortage in the region for enhanced food security. Subsequently, actors along the banana value chain are encouraged to target the intervention strategies based on the identified farmer, farm and institutional characteristics for enhanced impact on food provision. Opening up more TCB multiplication centres in different regions will make farmers access the TCB technology for enhanced impact on the target population.

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Contemporary African agricultural policy embodies the African Green Revolution’s drive towards modernisation and commercialisation. Agroecologists have criticised this movement on ecological, social and political grounds. Northern Ghanaian fertiliser credit schemes provide a good example through which these critiques can be examined in a context where agricultural policy reflects the African Green Revolution’s ideals. This study aimed to determine the relationship of such credit schemes to farmers’ use of organic amendments, elucidate other factors related to organic amendment use, and comment on the relevance of this modernisation policy and its relationship to agroecology. A first research phase employed semi-structured key informant interviews. Qualitative data from these informed construction of a semi-structured questionnaire that was used in a survey of 205 farmers. Multistage sampling purposively identified five villages and selected farmers within who had joined government and donor-funded fertiliser credit schemes. The use of organic and inorganic amendments was compared to that of peers who had not taken part in such schemes. Quantitative data were used in binomial logistic regression, inferential and descriptive statistics. Qualitative data were content analysed. Credit group membership was associated with higher fertiliser application and yield, but had little influence on the extent of commercialisation. Farmers who applied organic amendments were 40% less likely to belong to a fertiliser credit scheme than not, indicating substitution between organic and inorganic fertilisers. Organic amendments were 40% more likely to be applied to compound farms than outfields and six times more likely to be applied by household heads than other household members. However, household heads also preferentially joined credit groups. This was part of an agroecological soil fertility management strategy. Household heads appreciated the soil moisture retention properties of organic amendments, and applied them to compound farms to reduce risk to their household food supply in a semi-arid environment. They simultaneously accessed fertiliser to enhance this household provisioning strategy. They appreciated the increased yields this achieved, yet complained that the repayment terms of credit schemes were unfair, fertiliser did not enhance yields in dry conditions and fertilisers were supplied late. Farmers’ use of credited fertiliser alongside their existing agroecological strategy is helpful to the extent that it raises yields, yet is problematic in that it conflicts with risk-reduction strategies based on organics. There is some potential for modernised and agroecological management paradigms to coexist. For fertiliser credit to play a role in this, schemes must use fairer repayment terms and involve a focus on simultaneous use of organic amendments.

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© 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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Objectives: To characterise antimicrobial use (AMU) per production stage in terms of drugs, routes of application, indications, duration and exposed animals in farrow-to-finish pig farms in Spain. Design: Survey using a questionnaire on AMU during the six months prior to the interview, administered in face-to-face interviews completed from April to October 2010. Participants: 108 potentially eligible farms covering all the country were selected using a multistage sampling methodology; of these, 33 were excluded because they did not fulfil the participation criteria and 49 were surveyed. Results: The rank of the most used antimicrobials per farm and production stage and administration route started with polymyxins (colistin) by feed during the growing and the preweaning phases, followed by β-lactams by feed during the growing and the preweaning phases and by injection during the preweaning phase. Conclusions: The study demonstrates that the growing stage (from weaning to the start of finishing) has the highest AMU according to different quantitative indicators (number of records, number of antimicrobials used, percentage of farms reporting use, relative number of exposed animals per farm and duration of exposure); feed is the administration route that produces the highest antimicrobial exposure based on the higher number of exposed animals and the longer duration of treatment; and there are large differences in AMU among individual pig farms.

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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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2000 Mathematics Subject Classification: 62L10, 62L15.

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The aim of this study was to determine how abiotic factors drive the phytoplankton community in a water supply reservoir within short sampling intervals. Samples were collected at the subsurface (0.1 m) and bottom of limnetic (8 m) and littoral (2 m) zones in both the dry and rainy seasons. The following abiotic variables were analyzed: water temperature, dissolved oxygen, electrical conductivity, total dissolved solids, turbidity, pH, total nitrogen, nitrite, nitrate, total phosphorus, total dissolved phosphorus and orthophosphate. Phytoplankton biomass was determined from biovolume values. The role abiotic variables play in the dynamics of phytoplankton species was determined by means of Canonical Correspondence Analysis. Algae biomass ranged from 1.17×10(4) to 9.21×10(4) µg.L-1; cyanobacteria had biomass values ranging from 1.07×10(4) to 8.21×10(4) µg.L-1. High availability of phosphorous, nitrogen limitation, alkaline pH and thermal stability all favored cyanobacteria blooms, particularly during the dry season. Temperature, pH, total phosphorous and turbidity were key factors in characterizing the phytoplankton community between sampling times and stations. Of the species studied, Cylindrospermopsis raciborskii populations were dominant in the phytoplankton in both the dry and rainy seasons. We conclude that the phytoplankton was strongly influenced by abiotic variables, particularly in relation to seasonal distribution patterns.

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OBJECTIVE: We evaluated the relation between overweight and calcium intake in adults living in the municipality of São Paulo, Brazil. METHODS: This was a cross-sectional population-based study on a sample of 1459 adults that was obtained by multistage cluster sampling. Dietary intake was measured by the 24-h recall method. Poisson's and linear regression analyses were performed to evaluate the relation between overweight and quartiles of calcium intake adjusted for energy. RESULTS: The prevalence of overweight was 43.1% and the average adjusted calcium intake was 448.6 mg. In the linear regression analyses, the regression coefficient for adjusted calcium was significant and negative (P = 0.019, beta(1) = -0.0001). Although evaluated by quartiles, the prevalence ratio for overweight in the first quartile of calcium intake was 1.24 (95% confidence interval 1.00-1.54) and that in the second quartile was 1.24 (95% confidence interval 1.03-1.49). CONCLUSION: In the present study, calcium intake showed a significant negative association with body mass index