915 resultados para Sampling method


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Bee pollinators are currently recorded with many different sampling methods. However, the relative performances of these methods have not been systematically evaluated and compared. In response to the strong need to record ongoing shifts in pollinator diversity and abundance, global and regional pollinator initiatives must adopt standardized sampling protocols when developing large-scale and long-term monitoring schemes. We systematically evaluated the performance of six sampling methods (observation plots, pan traps, standardized and variable transect walks, trap nests with reed internodes or paper tubes) that are commonly used across a wide range of geographical regions in Europe and in two habitat types (agricultural and seminatural). We focused on bees since they represent the most important pollinator group worldwide. Several characteristics of the methods were considered in order to evaluate their performance in assessing bee diversity: sample coverage, observed species richness, species richness estimators, collector biases (identified by subunit-based rarefaction curves), species composition of the samples, and the indication of overall bee species richness (estimated from combined total samples). The most efficient method in all geographical regions, in both the agricultural and seminatural habitats, was the pan trap method. It had the highest sample coverage, collected the highest number of species, showed negligible collector bias, detected similar species as the transect methods, and was the best indicator of overall bee species richness. The transect methods were also relatively efficient, but they had a significant collector bias. The observation plots showed poor performance. As trap nests are restricted to cavity-nesting bee species, they had a naturally low sample coverage. However, both trap nest types detected additional species that were not recorded by any of the other methods. For large-scale and long-term monitoring schemes with surveyors with different experience levels, we recommend pan traps as the most efficient, unbiased, and cost-effective method for sampling bee diversity. Trap nests with reed internodes could be used as a complementary sampling method to maximize the numbers of collected species. Transect walks are the principal method for detailed studies focusing on plant-pollinator associations. Moreover, they can be used in monitoring schemes after training the surveyors to standardize their collection skills.

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Accurate differentiation between tropical forest and savannah ecosystems in the fossil pollen record is hampered by the combination of: i) poor taxonomic resolution in pollen identification, and ii) the high species diversity of many lowland tropical families, i.e. with many different growth forms living in numerous environmental settings. These barriers to interpreting the fossil record hinder our understanding of the past distributions of different Neotropical ecosystems and consequently cloud our knowledge of past climatic, biodiversity and carbon storage patterns. Modern pollen studies facilitate an improved understanding of how ecosystems are represented by the pollen their plants produce and therefore aid interpretation of fossil pollen records. To understand how to differentiate ecosystems palynologically, it is essential that a consistent sampling method is used across ecosystems. However, to date, modern pollen studies from tropical South America have employed a variety of methodologies (e.g. pollen traps, moss polsters, soil samples). In this paper, we present the first modern pollen study from the Neotropics to examine the modern pollen rain from moist evergreen tropical forest (METF), semi-deciduous dry tropical forest (SDTF) and wooded savannah (cerradão) using a consistent sampling methodology (pollen traps). Pollen rain was sampled annually in September for the years 1999–2001 from within permanent vegetation study plots in, or near, the Noel Kempff Mercado National Park (NKMNP), Bolivia. Comparison of the modern pollen rain within these plots with detailed floristic inventories allowed estimates of the relative pollen productivity and dispersal for individual taxa to be made (% pollen/% vegetation or ‘p/v’). The applicability of these data to interpreting fossil records from lake sediments was then explored by comparison with pollen assemblages obtained from five lake surface samples.

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The use of social network sites (SNS) has become very valuable to educational institutions. Some universities have formally integrated these social media in their educational systems and are using them to improve their service delivery. The main aim of this study was to establish whether African universities have embraced this emerging technology by having official presence on SNS. A purposive sampling method was used to study 24 universities from which data were obtained by visiting their official websites and following the official links to the most common SNS.

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We conducted a multi-stage household cluster survey to calculate hepatitis B vaccine coverage among children 18-30 months of age in 27 Brazilian cities. Hepatitis B vaccine is administered at birth, 1 month and 6 months of age by Brazil`s national immunization program. Among 17,749 children surveyed, 40.2% received a birth dose within one day of birth, 94.8% received at least one dose of hepatitis B vaccine, and 86.7% completed the three-dose series by 12 months of age. Increased coverage with the birth dose and administration of hepatitis B in combination with diphtheria-tetanus-pertussis-Haemophilus influenzae type b antigens could improve protection against hepatitis B. (C) 2009 Elsevier Ltd. All rights reserved.

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Com vários propósitos, inclusive o de redução de custos e o de facilitar a obtenção das informações desejadas pelo usuário, muitas empresas prestadoras de serviços ao consumidor adotam em suas CATs (Centrais de Atendimento Telefônico) recursos tecnológicos de automação da interação. Examinando-se sob a ótica dos usuários das CATs, estes poderão ter expectativas sobre o serviço que encontrarão e manifestar preferências com relação aos recursos de interação automática. As CATs, ao utilizarem tecnologias de automação da interação, podem estar ou não satisfazendo as expectativas e as preferências dos usuários. Para a determinação de argumentos que suportem as proposições levantadas durante a revisão bibliográfica sobre o tema, realizou-se uma pesquisa dividida em três partes: a) um focus group com alguns usuários de CATs; b) um estudo de campo com usuários de CATs; c) entrevistas com especialistas (levantamento de experiência). Com a técnica Análise de Preferência, propõe-se um modelo das preferências dos usuários em relação ao atendimento automático em CATs. Esse modelo, em princípio, não é generalizável devido às características do processo de amostragem utilizado nesse estudo exploratório. Determinaram-se três grupos distintos de usuários, de acordo com a similaridade entre suas preferências. Determinaram-se usos da tecnologia de atendimento automático que estão em sintonia com as preferências dos usuários. Finalmente, usando os conceitos do Balanced Scorecard, propõe-se um modelo de avaliação gerencial para o uso da tecnologia de atendimento automatizado nas Centrais de Atendimento Telefônico das empresas prestadoras de serviços ao consumidor.

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Obesity is currently considered a public health problem and there has been growing interest in the study of various aspects related to this infirmity such as: epidemiology, diagnosis, treatment, prevention and others. Thus, the purpose of this study was to determine the prevalence of weight excess and overweight in preschoolers in Natal, Brazil and relate them to variables such as gender, age, type of school (public or private) and zones of the city (east/south and north/west). This is a transversal study, carried out in Natal, Brazil between August and September 2004, in 20 public and 20 private schools/day care centers selected by the systematic sampling method. We measured the weight and height of 3721 students between the ages of 2 and 6 years. The children were stratified, according to age, into age group 1 (2 to 4 years) and age group 2 (5 and 6 years) and according to the region of the school, into north/west and east/south zones, the regions with the smallest and highest quality of life indices in the city, respectively. Children were considered to have weight excess when BMI ≥ 85th percentile, including those with BMI ≥ 95th percentile and overweight when BMI ≥ 95th percentile. The prevalence of weight excess was 26.5%, and of overweight 12.4%. There was greater prevalence of weight excess in the private schools and in the east/south zones. Overweight displayed the same epidemiologic profile, with a greater prevalence in private schools and in the east/south zones. The prevalence of weight excess in preschoolers in Natal, Brazil is high and is related, above all, to private schools and to those located in the highest quality of life areas. Therefore, prevention programs should be implanted in elementary schools in order to decrease weight excess and possible associated co-morbidities. This research project met the norms established by PPGCSa/UFRN and aimed at promoting the interrelation between different researchers and between different fields of knowledge, using multi and interdisciplinary concepts. This study was enriched by the interaction between the following professionals: pediatrician, pediatric gastroenterologist and physician nutrition specialist, pediatric endocrinologist, epidemiologist and biostatistician

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Estudou-se um método objetivo para a estimativa do número de frutos em pomares de laranja baseado na contagem dos frutos em ramos de 5 cm de diâmetro. Foram realizados levantamentos em laranjeiras durante três safras, obtendo-se o número de frutos produzidos em um ramo terminal, tomado ao acaso, bem como o número total na árvore. Consideraram-se nove estratos, constituídos pelas cultivares de laranja-doce, Hamlin, Pêra, Natal e Valência (as duas últimas analisadas conjuntamente) e três faixas etárias (três a cinco, seis a 10 e mais que 10 anos de idade). Foram ajustados modelos de regressão linear para o número total de frutos da árvore em função do número de frutos no ramo, obtendo-se coeficientes de determinação variando de 0,79 a 0,94. Com exceção da cultivar Hamlin, verificou-se coincidência entre as curvas das faixas etárias correspondentes. Esses resultados permitem estimar a produção média de frutos em um pomar de laranja, com base em amostragem de ramos com tamanho fixo, com precisão satisfatória, sem o uso de métodos de amostragem mais laboriosos e onerosos.

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A broca Diatraea saccharalis é uma das mais importantes pragas da cana-de-açúcar no Brasil. O manejo de áreas infestadas está embasado no controle biológico com Cotesia flavipes, cujas liberações são feitas em função da população de lagartas da praga em campo. Por esta razão, a estimativa desta população é de fundamental importância para o sucesso do programa de manejo. Assim, o objetivo do presente trabalho foi estudar a variabilidade espacial de D. saccharalis em canaviais e sugerir um método de amostragem que permitisse uma estimativa adequada das populações em campo. Seis campos de aproximadamente 1 ha cada um foram amostrados, em grid retangular de aproximadamente 10 x 10 m, com ilhas. Cada ponto de amostragem foi representado pela coleta das formas biológicas da praga no interior dos colmos em 2 m de sulco. Na maioria das áreas, as populações de formas imaturas de D. saccharalis distribuíram-se de forma contagiosa, com alcance do semivariograma variando de 18 a 80 m. Com base no alcance médio, estimou-se em seis o número médio de pontos de amostragem por hectare que deveriam ser feitos para representar adequadamente a área. Este número foi menor do que o estimado utilizando parâmetros da estatística clássica. Sugere-se que, para estimativa das formas imaturas de D. saccharalis em canaviais, a amostragem seja feita em grid de 40 x 40 m, o que resulta em aproximadamente seis pontos de amostragem por hectare e permitirá, na maioria das áreas, efetuar levantamentos com independência e coeficientes de variação menores que 50%.

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O conhecimento do modelo de distribuição espacial de pragas na cultura é fundamental para estabelecer um plano adequado de amostragem seqüencial e, assim, permitir a correta utilização das estratégias de controle e a otimização das técnicas de amostragem. Esta pesquisa objetivou estudar a distribuição espacial de lagartas de Alabama argillacea (Hübner) na cultura do algodoeiro, cultivar CNPA ITA-90. A coleta de dados ocorreu durante o ano agrícola de 1998/99 na Fazenda Itamarati Sul S.A., localizada no município de Ponta Porã, MS, em três diferentes áreas de 10.000 m² cada uma. Cada área amostral foi composta de 100 parcelas com 100 m² cada. Foi realizada semanalmente a contagem das lagartas pequenas, médias e grandes, encontradas em cinco plantas por parcela. Os índices de agregação (razão variância/média e índice de Morisita), o teste de qui-quadrado com o ajuste dos valores encontrados e esperados às distribuições teóricas de freqüência (Poisson, binomial positiva e binomial negativa), mostraram que todos os estádios das lagartas estão distribuídos de acordo com o modelo de distribuição contagiosa, ajustando-se ao padrão da Distribuição Binomial Negativa durante todo o período de infestação.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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O psilídeo-de-concha, Glycaspis brimblecombei, é uma praga exótica específica de Eucalyptus, que causa desfolha, secamento de ponteiros e ramos, podendo levar as árvores à morte. O parasitóide Psyllaephagus bliteus é indicado como principal agente no controle biológico desta praga. Portanto, o monitoramento adequado de as ambas espécies por um método eficiente de amostragem facilitaria o manejo para uma futura tomada de decisão. Devido à falta de informações referentes ao seu comportamento em plantações extensivas de eucalipto no Brasil, este trabalho teve como objetivo estudar as populações de G. brimblecombei e de P. bliteus em florestas de Eucalyptus camaldulensis, utilizando armadilhas amarelas para determinação de sua flutuação populacional e correlacionado-as com variáveis meteorológicas (temperatura e precipitação). A determinação da flutuação populacional (53 pontos amostrais) foi realizada em talhão de 19ha com E. camaldulensis em Luíz Antônio, SP, em 10avaliações quinzenais, entre janeiro e junho de 2005. As populações de ambas as espécies apresentaram correlação inversamente proporcional em função da temperatura e não há correlação com a precipitação no período avaliado.

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Os psilídeos são um grupo de pragas amplamente distribuídas, causando perdas consideráveis em sistemas agrícolas e florestais. A recente descoberta da ocorrência do psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), no Brasil tornou-se um problema de grande importância, por ser específico de Eucalyptus. O parasitóide Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) é indicado como principal agente no controle biológico desta praga. Portanto, para o monitoramento adequado de ambas espécies é necessário um método eficiente de amostragem. Devido a falta de informações referentes ao seu comportamento em plantações extensivas de eucalipto, realizou-se este trabalho, para verificar a distribuição espacial de G. brimblecombei e de seu parasitóide P. bliteus, através de armadilhas adesivas em floresta de E. camaldulensis. Para determinação da distribuição espacial foram utilizadas 53 armadilhas amarelas distribuídas uniformemente no talhão, formando uma grade amostral espaçadas de 50 x 36 m, à altura aproximada de 1,80 m do solo. Cada armadilha foi presa com auxílio de um arame plastificado em um fio estendido entre duas árvores em um talhão de 19 ha com E. camaldulensis em Luiz Antônio, SP. Foram realizadas dez avaliações, entre janeiro e junho de 2005. Após a coleta as armadilhas foram levadas ao laboratório para ser feita à triagem e contagem do número total de adultos de G. brimblecombei e de P. bliteus, nas duas faces das armadilhas. Concluiu-se que as populações de ambas espécies apresentaram distribuição espacial agregada, no período avaliado.

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Goats are social animals which groups are organized from dominance hierarchies, established by agonistic behaviors. The quality and productivity of the goat s milk can be influenced by the dominance hierarchy. In this context, the objectives of our work were describe the social and food behavior of Saanen goats in a semi-extensive production system; characterize the social organization from the assessment of dominance hierarchies in two seasonal periods and correlate the physicochemical quality of the goats milk according hierarchical position. The experiment was conducted in the EMPARN s experimental station, located in the district of Cruzeta/RN. We utilized 17 multiparous goats of the Saanen race, with different age and weight. The observations were performed in precipitation and drought phases. The scan method recorded the trough permanence and agonistic interactions by method "all occurrences" in the pasture the alimentary behaviors of eat, ruminate on foot, ruminate lying, leisure on foot, leisure lying and walk, by the focal animal sampling method. The goats milk was submitted to analyzes of: density, protein, fat, lactose, CSS and total solids. The animals spend most of the time feeding themselves, and the activities that demand greater energy expenditure are done in the morning. The animals changed the hierarchical structure during the seasonal periods because of the withdrawal of some individuals of the group, having more aggressive behavior in the rainy season. The dominant animal the lowet production, the more CSS and the lesser fat, the goat in the middle of the hierarchy was the one that obtained the best production and quality. We conclude that the Saanen goats adapt to the environment and the conditions of the group to ensure better survival and its production is influenced by the internal dynamics of the group

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Studies indicate that spinner dolphins use the Baía dos Golfinhos, in Fernando de Noronha Archipelago, for resting, reproduction, parental care and protection against shark attacks. The present study had the purpose of verifying the seasonality of spinner dolphin newborns and calves in relation to the months of the year and the pluviometric seasons (dry and rainy), as well as their interaction with the number and gender of accompanying adults and their positioning in relation to the adults (vertical, horizontal, and depth) in the above mentioned bay. The analysis were made out of photo records of dolphins collected between 2000 and 2006 (seasonality) and between 1995 and 2006 (interaction) both using ad libitum sampling method during free dives. To determine the age category, the reason between the smaller dolphin s total body length and the bigger dolphin s total body length was calculated. The dolphins were then divided into three age groups: adults, newborns and calves. Those with total body length ≥ 170cm were considered adults, newborns up to 105cm, and calves from 106cm to 128cm. In addition, the secondary characters described in literature were used to identify newborns and calves. The adults had dimensions of total lenght ≥170cm , the newborns until 105cm and calves between 106cm and 128cm. I addition, secondary characteristics described in the literature were used to indentify newborns and calves. The number of spinner dolphin newborns was greater in the month of April and higher during the rainy season. Throughout the months and pluviometric seasons (pluviometer/pluvial metric), the number of calves did not have a significant difference. Concerning to the presence of newborns and calves age groups at Baía dos Golfinhos, there was not a significant difference. It was possible to identify the gender of the escorting adults as (42), 95.24% being females and 4.76% males. Newborns were more frequently seen in the company of two adults, whereas calves were more often accompanied by more than two adults However, there was not a significant difference for the newborns, whereas for the calves there was a significant difference for those classified as loners and those accompanied by more than two adults. When in vertical positioning, the newborns and calves were more frequently observed in inferior position with some difference demonstrated between some of that. While in horizontal positioning both age groups were more often seen in posterior position, also with differences between them. In the depth perspective newborns and calves were positioned anterior, however with significant difference for the calves. The occurrence of a peak of newborns in the months of April may indicate the existence of a birth seasonality pattern for the beginning of the rainy season, with births scattered throughout the year. The results for the positions and escorting of newborns and calves are related to protection and suckling. These conditions reinforce the importance of the area when it comes to the care for offspring, which calls for the creation of conservation rules to the area, especially during those months with greater occurrence of newborns