932 resultados para Irregular sampling


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Koala (Phascolarctos cinereus) populations in eastern Australia are threatened by land clearing for agricultural and urban development. At the same time, conservation efforts are hindered by a dearth of information about inland populations. Faecal deposits offer a source of information that is readily available and easily collected non-invasively. We detail a faecal pellet sampling protocol that was developed for use in a large rangeland biogeographic region. The method samples trees in belt transects, uses a thorough search at the tree base to quickly identify trees with koala pellets under them, then estimates the abundance of faecal pellets under those trees using 1-m(2) quadrats. There was a strong linear relationship between these estimates and a complete enumeration of pellet abundance under the same trees. We evaluated the accuracy of our method in detecting trees where pellets were present by means of a misclassification index that was weighed more heavily for missed trees that had high numbers of pellets under them. This showed acceptable accuracy in all landforms except riverine, where some trees with large numbers of pellets were missed. Here, accuracy in detecting pellet presence was improved by sampling with quadrats, rather than basal searches. Finally, we developed a method to reliably age pellets and demonstrate how this protocol could be used with the faecal-standing-crop method to derive a regional estimate of absolute koala abundance.

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A balanced sampling plan excluding contiguous units (or BSEC for short) was first introduced by Hedayat, Rao and Stufken in 1988. These designs can be used for survey sampling when the units are arranged in one-dimensional ordering and the contiguous units in this ordering provide similar information. In this paper, we generalize the concept of a BSEC to the two-dimensional situation and give constructions of two-dimensional BSECs with block size 3. The existence problem is completely solved in the case where lambda = 1.

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Distance sampling using line transects has not been previously used or tested for estimating koala abundance. In July 2001, a pilot survey was conducted to compare the use of line transects with strip transects for estimating koala abundance. Both methods provided a similar estimate of density. On the basis of the results of the pilot survey, the distribution and abundance of koalas in the Pine Rivers Shire, south-east Queensland, was determined using line-transect sampling. In total, 134 lines (length 64 km) were used to sample bushland areas. Eighty-two independent koalas were sighted. Analysis of the frequency distribution of sighting distances using the software program DISTANCE enabled a global detection function to be estimated for survey sites in bushland areas across the Shire. Abundance in urban parts of the Shire was estimated from densities obtained from total counts at eight urban sites that ranged from 26 to 51 ha in size. Koala abundance in the Pine Rivers Shire was estimated at 4584 (95% confidence interval, 4040-5247). Line-transect sampling is a useful method for estimating koala abundance provided experienced koala observers are used when conducting surveys.

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Despite extensive efforts to confirm a direct association between Chlamydia pneumoniae and atherosclerosis, different laboratories continue to report a large variability in detection rates. In this study, we analyzed multiple sections from atherosclerotic carotid arteries from 10 endartectomy patients to determine the location of C. pneumoniae DNA and the number of sections of the plaque required for analysis to obtain a 95% confidence of detecting the bacterium. A sensitive nested PCR assay detected C. pneumoniae DNA in all patients at one or more locations within the plaque. On average, 42% (ranging from 5 to 91%) of the sections from any single patient had C. pneumoniae DNA present. A patchy distribution of C. pneumoniae in the atherosclerotic lesions was observed, with no area of the carotid having significantly more C. pneumoniae DNA present. If a single random 30-mum-thick section was tested, there was only a 35.6 to 41.6% (95% confidence interval) chance of detecting C. pneumoniae DNA in a patient with carotid artery disease. A minimum of 15 sections would therefore be required to obtain a 95% chance of detecting all true positives. The low concentration and patchy distribution of C. pneumoniae DNA in atherosclerotic plaque appear to be among the reasons for inconsistency between laboratories in the results reported.

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Background: The surgical cure rate for primary hyperparathyroidism is greater than 95%. For those who have recurrent or persistent disease, preoperative localization improves reoperation success rates. Selective parathyroid venous sampling (SPVS) for intact parathyroid hormone is particularly useful when non-invasive localization techniques are negative or inconclusive. Methods: We present all known cases (n = 13) between 1994 and 2002 who had venous sampling for localization at our institution prior to reoperation for recurrent or persistent primary hyperparathyroidism. Comparison was made with non-invasive localization procedures. Results of invasive and non-invasive localization were correlated with surgical findings. Results: Of the nine reoperated cases, eight had positive correlations between SPVS and operative findings and histopathology. SPVS did not reveal the parathyroid hormone source in one case with negative non-invasive localization procedures. Comparisons between SPVS, computerized tomography (CT), and parathyroid scintigraphy (MIBI) as expressed in terms of true positive (TP), false positive (FP) and false negative (FN) were: SPVS - TP 88.8%, FP 0%, FN 11.1%; CT - TP 22.2%, FP 22.2%, FN 55.5%; and MIBI - TP 33.3%, FP 0%, FN 66.6%. At least seven of the nine operated cases have been cured; another remained normocalcaemic 2 weeks after subtotal parathyroidectomy. Conclusion: In our institution SPVS has proven to be a valuable tool in cases with recurrent or persistent primary hyperparathyroidism and negative non-invasive localization procedures.

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The BALA project (Biodiversity of Arthropods of Laurisilva of the Azores) is a research initiative to quantify the spatial distribution of arthropod biodiversity in native forests of the Azores archipelago. Arthropods were collected using a combination of two techniques, targeting epigean (ground dwelling) and canopy (arboreal) arthropods: pitfall traps (with Turquin and Ethylene solutions) and beating samples (using the three most dominant plant species). A total of 109 transects distributed amongst 18 forest fragments in seven of the nine Azorean islands were used in this study. The performance of alternative sampling methods and effort were tested. No significant differences were found in the accumulated number of species captured whether an alternative method was used or whether another transect with similar effort was established in another location within the same fragment. A combination of Ethylene and Turquin traps captured more species per individual, Turquin and beating captured more species per sample, and Turquin captured more species per unit time. An optimization exercise was performed and we found that the protocol applied during recent years is very close to optimal, allowing its future replication with confidence. The minimum combinations of sampling effort and methods, in order to monitor or to inventory diversity, taking into account different proportions of sample completeness are discussed.

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We are launching a long-term study to characterize the biodiversity at different elevations in several Azorean Islands. Our aim is to use the Azores as a model archipelago to answer the fundamental question of what generates and maintains the global spatial heterogeneity of diversity in islands and to be able to understand the dynamics of change across time. An extensive, standardized sampling protocol was applied in most of the remnant forest fragments of five Azorean Islands. Fieldwork followed BRYOLAT methodology for the collection of bryophytes, ferns and other vascular plant species. A modified version of the BALA protocol was used for arthropods. A total of 70 plots (10 m x 10 m) are already established in five islands (Flores, Pico, São Jorge, Terceira and São Miguel), all respecting an elevation step of 200 m, resulting in 24 stations examined in Pico, 12 in Terceira, 10 in Flores, 12 in São Miguel and 12 in São Jorge. The first results regarding the vascular plants inventory include 138 vascular species including taxa from Lycopodiophyta (N=2), Pteridophyta (N=27), Pinophyta (N=2) and Magnoliophyta (N=107). In this contribution we also present the main research question for the next six years within the 2020 Horizon.

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OBJECTIVE: To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers.METHODS: A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support.RESULTS: Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively). The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05). Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively) than moderately-active day-shift workers (116 and 73.3 mmHg, respectively) (p < 0.05) as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively) (p = 0.01). Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively) than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05).CONCLUSIONS: Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical activity.

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Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic and health aspects of the human life. Surface temperature time-series characterise Earth as a slow dynamics spatiotemporal system, evidencing long memory behaviour, typical of fractional order systems. Such phenomena are difficult to model and analyse, demanding for alternative approaches. This paper studies the complex correlations between global temperature time-series using the Multidimensional scaling (MDS) approach. MDS provides a graphical representation of the pattern of climatic similarities between regions around the globe. The similarities are quantified through two mathematical indices that correlate the monthly average temperatures observed in meteorological stations, over a given period of time. Furthermore, time dynamics is analysed by performing the MDS analysis over slices sampling the time series. MDS generates maps describing the stations’ locus in the perspective that, if they are perceived to be similar to each other, then they are placed on the map forming clusters. We show that MDS provides an intuitive and useful visual representation of the complex relationships that are present among temperature time-series, which are not perceived on traditional geographic maps. Moreover, MDS avoids sensitivity to the irregular distribution density of the meteorological stations.

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One of the most important measures to prevent wild forest fires is the use of prescribed and controlled burning actions as it reduce the fuel mass availability. The impact of these management activities on soil physical and chemical properties varies according to the type of both soil and vegetation. Decisions in forest management plans are often based on the results obtained from soil-monitoring campaigns. Those campaigns are often man-labor intensive and expensive. In this paper we have successfully used the multivariate statistical technique Robust Principal Analysis Compounds (ROBPCA) to investigate on the sampling procedure effectiveness for two different methodologies, in order to reflect on the possibility of simplifying and reduce the sampling collection process and its auxiliary laboratory analysis work towards a cost-effective and competent forest soil characterization.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Informática

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Mathematical models and statistical analysis are key instruments in soil science scientific research as they can describe and/or predict the current state of a soil system. These tools allow us to explore the behavior of soil related processes and properties as well as to generate new hypotheses for future experimentation. A good model and analysis of soil properties variations, that permit us to extract suitable conclusions and estimating spatially correlated variables at unsampled locations, is clearly dependent on the amount and quality of data and of the robustness techniques and estimators. On the other hand, the quality of data is obviously dependent from a competent data collection procedure and from a capable laboratory analytical work. Following the standard soil sampling protocols available, soil samples should be collected according to key points such as a convenient spatial scale, landscape homogeneity (or non-homogeneity), land color, soil texture, land slope, land solar exposition. Obtaining good quality data from forest soils is predictably expensive as it is labor intensive and demands many manpower and equipment both in field work and in laboratory analysis. Also, the sampling collection scheme that should be used on a data collection procedure in forest field is not simple to design as the sampling strategies chosen are strongly dependent on soil taxonomy. In fact, a sampling grid will not be able to be followed if rocks at the predicted collecting depth are found, or no soil at all is found, or large trees bar the soil collection. Considering this, a proficient design of a soil data sampling campaign in forest field is not always a simple process and sometimes represents a truly huge challenge. In this work, we present some difficulties that have occurred during two experiments on forest soil that were conducted in order to study the spatial variation of some soil physical-chemical properties. Two different sampling protocols were considered for monitoring two types of forest soils located in NW Portugal: umbric regosol and lithosol. Two different equipments for sampling collection were also used: a manual auger and a shovel. Both scenarios were analyzed and the results achieved have allowed us to consider that monitoring forest soil in order to do some mathematical and statistical investigations needs a sampling procedure to data collection compatible to established protocols but a pre-defined grid assumption often fail when the variability of the soil property is not uniform in space. In this case, sampling grid should be conveniently adapted from one part of the landscape to another and this fact should be taken into consideration of a mathematical procedure.

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Introdução: A utilização de serviços de saúde tem implicações importantes para o estado de saúde das populações. As políticas de imigração adoptadas nos países de destino têm influência no estado de saúde das comunidades imigrantes. Políticas que limitam o acesso de imigrantes aos cuidados de saúde aumentarão a vulnerabilidade e os riscos na saúde. Apesar da imigração promover uma série de rupturas na vida do sujeito, migrar, por si só, não pode ser considerado como factor de risco no âmbito da saúde e da saúde mental. O peso dos determinantes socioeconómicos tem ganho relevância no estudo das migrações, estado de saúde geral e mental. Isto porque, em geral, os imigrantes estão em situação mais precária do que a população autóctone. O estatuto socioeconómico baixo, as condições precárias de habitação e de trabalho, a falta de suporte social e a irregularidade jurídica são indicadores de risco acrescido para a saúde mental. Neste sentido é um desafio de monta os governos estabelecerem medidas sustentadas e, simultaneamente, integradoras dos imigrantes. Em Portugal, considera-se que há escassez de estudos relacionados com a área das migrações e da saúde.Metodologia: Estudo exploratório, descritivo e transversal. A finalidade foi a de identificar o estado de saúde, saúde mental e qualidade de vida da comunidade brasileira residente em Lisboa e o seu acesso aos serviços de saúde. Este estudo teve como principais objectivos a caracterização sociodemográfica, a identificação de variáveis inerentes ao processo migratório, a identificação da auto-apreciação do estado de saúde, a caracterização do acesso aos cuidados de saúde, a identificação do grupo em provável sofrimento psicológico, a comparação entre os resultados dos imigrantes juridicamente regulares e irregulares e a comparação entre a população imigrante e a população portuguesa. Inicialmente, foi prevista a utilização da técnica de amostragem de propagação geométrica ou snowball, pois a amostra tornar-se-ia maior à medida que os próprios inquiridos identificam outros potenciais respondentes. Ao longo do estudo, a metodologia inicial mostrou-se insuficiente para estabelecer uma amostra mais representativa dos imigrantes juridicamente irregulares. Para este feito, foi utilizada a metodologia de amostragem por conveniência e o local escolhido para a recolha da amostra foi o Consulado do Brasil em Lisboa. O instrumento de recolha de dados empregue baseou-se no questionário utilizado no 4º Inquérito Nacional de Saúde. O MHI-5 (Mental Health Index 5) é um instrumento de saúde mental e é parte integrante do inquérito, sendo recomendado pela Organização Mundial de Saúde. Consta de cinco itens relativos à saúde mental e os resultados são classificados através de um indicador que mede a existência de provável sofrimento psicológico. Foram incluídos no estudo 213 brasileiros. De seguida, procedeu-se ao tratamento estatístico dos dados. Resultados: A população inquirida é jovem, a maior parte tem entre 18 e 44 anos. As mulheres representam mais de metade da amostra. A taxa de actividade é elevada e a taxa de desemprego é similar à nacional. A inserção laboral prioritária é nos segmentos pouco qualificados ou de semi-qualificação. Aproximadamente um terço dos inquiridos afirmou ser beneficiário do Sistema Nacional de Saúde. A autoapreciação do estado de saúde é classificada como bastante positiva, assim como a qualidade de vida. O provável sofrimento psicológico, definido no MHI-5 pelo ponto de corte no score 52, atinge 23,3% dos participantes. Os homens apresentam melhores resultados do que as mulheres. Além disso, para os valores mais baixos no MHI-5 foram encontradas relações com as longas jornadas de trabalho e o diagnóstico de doença crónica.Discussão: O presente estudo apresenta limitações em relação à dimensão da amostra e à provável existência de enviesamento pela ausência de aleatorização. Apesar da legislação portuguesa garantir o acesso aos serviços de saúde e garantir a equidade no caso dos imigrantes que fazem descontos para a Segurança Social, apenas um terço referiu ser beneficiário do Sistema Nacional de Saúde. Este dado pode ser justificado por factores como o cumprimento da lei por alguns serviços e, também, pela falta de conhecimento da legislação e da forma de funcionamento do Serviço Nacional de Saúde por parte dos imigrantes. O facto das mulheres representarem o maior grupo em provável sofrimento psicológico é consistente com a literatura. As hipóteses levantadas para explicar este resultado podem ser agrupadas em: artefactos metodológicos, causalidade biológica e determinação social. Em relação ao instrumento, é possível que o MHI-5 se comporte de forma diferente no que diz respeito ao género.-------------------------------------------Introduction: The utilization of health services has important implications for the health state of the populations. The immigration policies adopted in the destiny countries are going to influence the health state of immigrant communities. Policies that limit the access of immigrants to health care are going to increase the vulnerability and the risk factor in health. Although immigration promotes several disruptive actions in ones life, migrating, on its own, cannot be considered as a risk factor for health and mental health. The preponderance of the socioeconomic factors has gained relevance in the study of migrations and also in the study of general health state and mental health. This happens because, in general, immigrants are in a more unfavorable situation compared with the destiny country population. The low socioeconomic status, the poor working and housing conditions, the lack of social support and the juridical irregularity are indicators of the incremented risk to mental health. Therefore, it is a major challenge for governments to find sustainable, and simultaneously, integrative measures for the immigrants. The studies related with the migrations and health in Portugal were considered to be few.Methods: It is an exploratory, descriptive and transversal study. The purpose is to identify the health state, mental health, quality of life and the access to health care of the Brazilian community resident in Lisbon. In addition, this study has as main goals the sociodemographic characterization, the variables identification inherent to the migrating process, the identification of the self-appreciation of health state, the characterization of the access to health care, the identification of the group in probable psychological suffer, the comparison between the results of regular and irregular immigrants and the comparison between the immigrant population and the Portuguese population. Initially it was predicted the utilization of the geometric propagation or “snowball”, as sampling technique, because the sample becomes larger as one answerer identify other potential answering persons. Along with the study, the methodology has shown insufficient to establish a more representative sample of the irregular immigrants. For this latter case, it was used a convenient sample methodology and the place chosen for the sample gathering was the “Consulate of Brazil in Lisbon”. The instrument was based in the questionnaire used in the “4th National Health Inquiry”. The MHI-5 (Mental Health Index 5) is a mental health instrument which is part of the enquiry and it is recommended by the World Health Organization. There are five items related to mental health and the results are classified through an indicator which measures the existence of a probable psychological suffer. It were included 213 Brazilian in the study. After, the statistical treatment of the data took place.Results: The answering population is young and the majority is between the 18 and 44 years of age. The women represent more than one half of the sample. The activity rate is high and the unemployment rate is similar to the national one. The priority labor insertion is in the few qualified or of semi-qualification segments. Approximately, one third of the answering people has stated to be beneficiary of the National Health System. The self-appreciation of the health state as well as the quality of life are classified as fairly positive ones. The probable psychological suffer, as defined in the MHI-5 through the cut point in the score below or equal to 52, reaches 23,3% of the sample population. Men show the better results than women. Further, for the lower values of MHI-5 it was found a relation with the long work periods and chronic disease diagnostic. Discussion: The present study evidences limitations in relation to the sample dimension and in relation to the existence of biases due to the lack of randomness. Although the Portuguese legislation guarantees the access to health services and the equality in the cases of the immigrants that do their Social Security discounts, only one third has mentioned to be beneficiary of the National Health System. This can be justified by several facts such as the non-fulfillment of law by some national services or the lack of knowledge of the legislation or the functioning process of the National Health System. Women representing the bigger group in probable psychological suffer has been coherent with the literature review. The hypothesis set to explain this result might be grouped in: methodological artifacts, biologic cause and social determination. In relation to the instrument used, it may be that MHI-5 behaves in a different way in respect to gender.

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Dissertation presented to obtain the Doutoramento (Ph.D.) degree in Biochemistry at the Instituto de Tecnologia Qu mica e Biol ogica da Universidade Nova de Lisboa