Screen Space Ambient Occlusion Based Multiple Importance Sampling for Real-Time Rendering

Science.gov (United States)

Zerari, Abd El Mouméne; Babahenini, Mohamed Chaouki

2018-03-01

We propose a new approximation technique for accelerating the Global Illumination algorithm for real-time rendering. The proposed approach is based on the Screen-Space Ambient Occlusion (SSAO) method, which approximates the global illumination for large, fully dynamic scenes at interactive frame rates. Current algorithms that are based on the SSAO method suffer from difficulties due to the large number of samples that are required. In this paper, we propose an improvement to the SSAO technique by integrating it with a Multiple Importance Sampling technique that combines a stratified sampling method with an importance sampling method, with the objective of reducing the number of samples. Experimental evaluation demonstrates that our technique can produce high-quality images in real time and is significantly faster than traditional techniques.

Convergence and Efficiency of Adaptive Importance Sampling Techniques with Partial Biasing

Science.gov (United States)

Fort, G.; Jourdain, B.; Lelièvre, T.; Stoltz, G.

2018-04-01

We propose a new Monte Carlo method to efficiently sample a multimodal distribution (known up to a normalization constant). We consider a generalization of the discrete-time Self Healing Umbrella Sampling method, which can also be seen as a generalization of well-tempered metadynamics. The dynamics is based on an adaptive importance technique. The importance function relies on the weights (namely the relative probabilities) of disjoint sets which form a partition of the space. These weights are unknown but are learnt on the fly yielding an adaptive algorithm. In the context of computational statistical physics, the logarithm of these weights is, up to an additive constant, the free-energy, and the discrete valued function defining the partition is called the collective variable. The algorithm falls into the general class of Wang-Landau type methods, and is a generalization of the original Self Healing Umbrella Sampling method in two ways: (i) the updating strategy leads to a larger penalization strength of already visited sets in order to escape more quickly from metastable states, and (ii) the target distribution is biased using only a fraction of the free-energy, in order to increase the effective sample size and reduce the variance of importance sampling estimators. We prove the convergence of the algorithm and analyze numerically its efficiency on a toy example.

Trophic systems and chorology: data from shrews, moles and voles of Italy preyed by the barn owl / Sistemi trofici e corologia: dati su <em>Soricidae>, <em>Talpidae> ed <em>Arvicolidae> d'Italia predati da <em>Tyto albaem> (Scopoli 1769

Directory of Open Access Journals (Sweden)

Longino Contoli

1986-12-01

Full Text Available Abstract In small Mammals biogeography, available data are up to now by far too scanty for elucidate the distribution of a lot of taxa, especially with regard to the absence from a given area. In this respect, standardized quantitative sampling techniques, like Owl pellets analysis can enable not only to enhance faunistic knowledges, but also to estimate the actual absence probability of a given taxon "m", lacking from the diet of an individual raptor. For the last purpose, the relevant frequencies of "m" in the other ecologically similar sites of the same raptor species diets are averaged ($f_m$ : the relevant standard error (multiplicated by a coefficient, according to the desired degree of accuracy, in relation of the integral of probabilities subtracted ($overline{F}_m - a E$: then, the probability that a single specimen is not pertaining to "m" is obtained ($P_0 = 1 - F_m + a E$; lastly, the desiderate accuracy probability ($P_d$ is chosen. Now, "$N_d$" (the number of individuals of all prey species in a single site needed for obtain, with the desired probability, a specimen at least of "m" is obtained through $$N = frac{ln P_d}{ln P_0}$$ Obviously, every site-diet with more than "N" preyed individuals and without any "i" specimen is considered to be lacking of such taxon. A "usefulness index" for the above purposes is outlined and checked about three raptors. Some exanples about usefulness of the Owl pellet analysis method in biogeography are given, concerning <em>Tyto albaem> diets in peninsular Italy about: - <em>Sorex minutusem>, lacking in some quite insulated areas; - <em>Sorex araneusem> (sensu stricto, after GRAF et al., 1979, present also in lowland areas in Emilia-Romagna; - <em>Crocidura suaveolensem> and - <em>Suncus etruscusem>, present also in the southermost part of Calabria (Reggio province; - <em>Talpa caecaem>, present also in the Antiapennines of Latium (Cimini mounts; - <em>Talpa romanaem

Performance evaluation of an importance sampling technique in a Jackson network

Science.gov (United States)

brahim Mahdipour, E.; Masoud Rahmani, Amir; Setayeshi, Saeed

2014-03-01

Importance sampling is a technique that is commonly used to speed up Monte Carlo simulation of rare events. However, little is known regarding the design of efficient importance sampling algorithms in the context of queueing networks. The standard approach, which simulates the system using an a priori fixed change of measure suggested by large deviation analysis, has been shown to fail in even the simplest network settings. Estimating probabilities associated with rare events has been a topic of great importance in queueing theory, and in applied probability at large. In this article, we analyse the performance of an importance sampling estimator for a rare event probability in a Jackson network. This article carries out strict deadlines to a two-node Jackson network with feedback whose arrival and service rates are modulated by an exogenous finite state Markov process. We have estimated the probability of network blocking for various sets of parameters, and also the probability of missing the deadline of customers for different loads and deadlines. We have finally shown that the probability of total population overflow may be affected by various deadline values, service rates and arrival rates.

Prevalência de Chlamydia trachomathis em amostras endocervicais de mulheres em São Paulo e Santa Catarina pela PCR Prevalence of Chlamydia trachomatis in endocervical samples by PCR in São Paulo and Santa Catarina

Directory of Open Access Journals (Sweden)

Marcos Edgar Herkenhoff

2012-10-01

Full Text Available INTRODUÇÃO: Nenhuma outra doença sexualmente transmissível (DST tem mostrado frequência tão elevada quanto a infecção por Chlamydia trachomatis (CT. É frequente a detecção de mulheres portadoras de danos tubários causados por esse agente, determinando infertilidade permanente e as intervenções cirúrgicas não têm demonstrado sucesso em reparar esses danos. A reação em cadeia da polimerase (PCR se mostrou mais sensível do que a cultura para a identificação de CT, principalmente em cervicite clamidiana nas mulheres. A PCR promove a detecção de sequências específicas de nucleotídeos para a CT. OBJETIVO: Analisar a prevalência de infecções causadas pela CT em mulheres nos estados de São Paulo e Santa Catarina utilizando amostras endocervicais. MATERIAIS E MÉTODOS Utilizaram-se para o presente trabalho amostras enviadas pelos laboratórios conveniados ao Genolab, pertencentes aos estados de São Paulo e de Santa Catarina. Foram consultados os resultados dos laudos de exames para CT oriundos do banco de dados do Genolab no ano de 2010. Para a obtenção e o isolamento do ácido desoxirribonucleico (DNA, utilizou-se a técnica de fenol-clorofórmio e para a amplificação do material genético, a técnica de PCR. RESULTADOS: Obteve-se uma amostra de 287 indivíduos, e desse total 56,45% das mulheres eram positivas. A amostra que obteve o maior número de positivos foi o swab endocervical, com 75%. CONCLUSÃO: As amostras biológicas provenientes do endocérvix apresentaram detecção eficiente da CT na população feminina. A alta prevalência salienta a importância no emprego do diagnóstico molecular, principalmente por este trabalho apontar esse aspecto.INTRODUCTION: No other sexually transmitted disease (STD has been as frequent as Chlamydia trachomatis (CT infection. Tubal damage caused by this agent has been frequently detected among women. This infection causes permanent infertility. Furthermore, surgical

Supercritical Fluid Extraction of <em>Eucalyptus globulusem> Bark—A Promising Approach for Triterpenoid Production<em>>

Directory of Open Access Journals (Sweden)

Carlos M. Silva

2012-06-01

Full Text Available Eucalyptus bark contains significant amounts of triterpenoids with demonstrated bioactivity, namely triterpenic acids and their acetyl derivatives (ursolic, betulinic, oleanolic, betulonic, 3-acetylursolic, and 3-acetyloleanolic acids. In this work, the supercritical fluid extraction (SFE of <em>Eucalyptus> <em>globulus> deciduous bark was carried out with pure and modified carbon dioxide to recover this fraction, and the results were compared with those obtained by Soxhlet extraction with dichloromethane. The effects of pressure (100–200 bar, co-solvent (ethanol content (0, 5 and 8% wt, and multistep operation were studied in order to evaluate the applicability of SFE for their selective and efficient production. The individual extraction curves of the main families of compounds were measured, and the extracts analyzed by GC-MS. Results pointed out the influence of pressure and the important role played by the co-solvent. Ethanol can be used with advantage, since its effect is more important than increasing pressure by several tens of bar. At 160 bar and 40 °C, the introduction of 8% (wt of ethanol greatly improves the yield of triterpenoids more than threefold.

Occurrence of Giardia cysts and Cryptosporidium oocysts in activated sludge samples in Campinas, SP, Brazil Ocorrência de cistos de Giardia e oocistos de Cryptosporidium em amostras de lodo ativado em Campinas, SP, Brasil

Directory of Open Access Journals (Sweden)

Luciana Urbano Santos

2004-04-01

Full Text Available Giardia and Cryptosporidium have caused several outbreaks of gastroenteritis in humans associated with drinking water. Contaminated sewage effluents are recognized as a potential source of waterborne protozoa. Due to the lack of studies about the occurrence of these parasites in sewage samples in Brazil, we compared the efficiency of two procedures for concentrating cysts and oocysts in activated sludge samples of one sewage treatment plant. For this, the samples were submitted to i concentration by the ether clarification procedure (ECP and to ii purification by sucrose flotation method (SFM and aliquots of the pellets were examined by immunofluorescence. Giardia cysts were present in all samples (100.0%; n = 8 when using ECP and kit 1 reagents, while kit 2 resulted in six positive samples (85.7%; n = 7. As for SFM, cysts were detected in 75.0% and 100.0% of these samples (for kit 1 and 2, respectively. Regarding Cryptosporidium, two samples (25.0%; kit 1 and 28.5% for kit 2 were detected positive by using ECP, while for SFM, only one sample (examined by kit 1 was positive (12.5%. The results of the control trial revealed Giardia and Cryptosporidium recovery efficiency rates for ECP of 54.5% and 9.6%, while SFM was 10.5% and 3.2%, respectively. Considering the high concentration detected, a previous evaluation of the activated sludge before its application in agriculture is recommended and with some improvement, ECP would be an appropriate simple technique for protozoa detection in sewage samples.Giardia e Cryptosporidium causaram vários surtos epidêmicos de gastroenterite, associados à água potável. Efluentes de esgoto contaminados foram incriminados como uma fonte potencial de cistos e oocistos. Uma investigação foi conduzida para verificar a presença de cistos de Giardia e oocistos de Cryptosporidium em amostras de lodo ativado de uma Estação de Tratamento de Esgoto. Para isto as amostras foram submetidas: i a concentração pelo

Adaptive control of theophylline therapy: importance of blood sampling times.

Science.gov (United States)

D'Argenio, D Z; Khakmahd, K

1983-10-01

A two-observation protocol for estimating theophylline clearance during a constant-rate intravenous infusion is used to examine the importance of blood sampling schedules with regard to the information content of resulting concentration data. Guided by a theory for calculating maximally informative sample times, population simulations are used to assess the effect of specific sampling times on the precision of resulting clearance estimates and subsequent predictions of theophylline plasma concentrations. The simulations incorporated noise terms for intersubject variability, dosing errors, sample collection errors, and assay error. Clearance was estimated using Chiou's method, least squares, and a Bayesian estimation procedure. The results of these simulations suggest that clinically significant estimation and prediction errors may result when using the above two-point protocol for estimating theophylline clearance if the time separating the two blood samples is less than one population mean elimination half-life.

Importância das características morfológicas e agronômicas no estudo da biodiversidade genética em milho

Directory of Open Access Journals (Sweden)

E. A. Rotili

2015-12-01

Full Text Available O milho, um dos cereais mais utilizados no mundo para alimentação humana e animal, é fonte de renda para várias famílias, quer seja na agricultura familiar ou em grandes propriedades. O trabalho teve como objetivo reunir resultados de pesquisas publicadas em periódicos revelando a importância relativa de características morfológicas e agronômicas da diversidade genética em milho. Devido à importância econômica e social deste cereal, a identificação de genótipos produtivos, sob condições ótimas ou de estresses, oriundos de diferentes programas de melhoramento genético, pode trazer grandes benefícios, tais como o aumento da produção e redução de insumos que reflete, em última instância, em uma diminuição de custos de produção e impactos ambientais. Neste sentido, é necessário conhecer a importância relativa de características para estudos sobre a diversidade genética, que podem auxiliar na escolha de genótipos potencialmente promissosres para as diferentes condições de cultivo. Na estimativa da importância relativa, os atributos encontrados com maior frequência nos trabalhos estudados foram: produtividade de grãos, altura de espiga, altura de planta, comprimento de espiga, diâmetro de espiga e massa de grãos. Importance of morphological and agronomic characteristics in the study of genetic biodiversity in maizeAbstract: Maize is one of the most commonly used cereal in the world, as in food or feed, and it is source of income for many families. The aim of this work was reunite the results of scientific articles about the relative importance of morphological and agronomic traits on maize genetic diversity. Due to the economic and social importance of this cereal, the identification of productive genotypes under stress conditions or not, from various breeding programs, can be promote benefits such as increased production, reduction of inputs and thus with decrease of production costs and environmental

The study of importance sampling in Monte-carlo calculation of blocking dips

International Nuclear Information System (INIS)

Pan Zhengying; Zhou Peng

1988-01-01

Angular blocking dips around the axis in Al single crystal of α-particles of about 2 Mev produced at a depth of 0.2 μm are calculated by a Monte-carlo simulation. The influence of the small solid angle emission of particles and the importance sampling in the solid angle emission have been investigated. By means of importance sampling, a more reasonable results with high accuracy are obtained

Hybrid algorithm of ensemble transform and importance sampling for assimilation of non-Gaussian observations

Directory of Open Access Journals (Sweden)

Shin'ya Nakano

2014-05-01

Full Text Available A hybrid algorithm that combines the ensemble transform Kalman filter (ETKF and the importance sampling approach is proposed. Since the ETKF assumes a linear Gaussian observation model, the estimate obtained by the ETKF can be biased in cases with nonlinear or non-Gaussian observations. The particle filter (PF is based on the importance sampling technique, and is applicable to problems with nonlinear or non-Gaussian observations. However, the PF usually requires an unrealistically large sample size in order to achieve a good estimation, and thus it is computationally prohibitive. In the proposed hybrid algorithm, we obtain a proposal distribution similar to the posterior distribution by using the ETKF. A large number of samples are then drawn from the proposal distribution, and these samples are weighted to approximate the posterior distribution according to the importance sampling principle. Since the importance sampling provides an estimate of the probability density function (PDF without assuming linearity or Gaussianity, we can resolve the bias due to the nonlinear or non-Gaussian observations. Finally, in the next forecast step, we reduce the sample size to achieve computational efficiency based on the Gaussian assumption, while we use a relatively large number of samples in the importance sampling in order to consider the non-Gaussian features of the posterior PDF. The use of the ETKF is also beneficial in terms of the computational simplicity of generating a number of random samples from the proposal distribution and in weighting each of the samples. The proposed algorithm is not necessarily effective in case that the ensemble is located distant from the true state. However, monitoring the effective sample size and tuning the factor for covariance inflation could resolve this problem. In this paper, the proposed hybrid algorithm is introduced and its performance is evaluated through experiments with non-Gaussian observations.

Relação da Importância dos Recursos Estratégicos com as Medidas de Desempenho em Empresas Brasileiras

Directory of Open Access Journals (Sweden)

Ilse Maria Beuren

2016-04-01

Full Text Available O estudo objetiva verificar se as medidas de desempenho são variáveis mediadoras entre a importância dos recursos estratégicos e a avaliação de desempenho em empresas brasileiras. De modo específico o estudo busca investigar a percepção dos gestores quanto à importância atribuída às medidas de desempenho tradicionais e não tradicionais e aos recursos estratégicos de capital humano, estrutural e físico em empresas brasileiras. O estudo pauta-se na pesquisa realizada por Widener (2006 em empresas norte americanas. Assim, um levantamento foi realizado junto aos gestores das empresas listadas na BM&FBovespa nos níveis 1 e 2 de Governança Corporativa. Na análise dos dados foi aplicada estatística descritiva e análise fatorial. Os resultados mostram que os gestores atribuem importância a várias medidas de desempenho, mas a estatística descritiva evidencia que a maior importância é atribuída às medidas de retorno e financeiras tradicionais. Dentre os recursos estratégicos, o capital humano desponta como o recurso mais importante para as empresas analisadas, seguido do capital estrutural e do capital físico. A partir das relações estabelecidas na pesquisa de base e aplicadas neste estudo, conclui-se que as medidas de desempenho são variáveis mediadoras entre a importância dos recursos estratégicos e o desempenho na percepção dos gestores.

Time-dependent importance sampling in semiclassical initial value representation calculations for time correlation functions.

Science.gov (United States)

Tao, Guohua; Miller, William H

2011-07-14

An efficient time-dependent importance sampling method is developed for the Monte Carlo calculation of time correlation functions via the initial value representation (IVR) of semiclassical (SC) theory. A prefactor-free time-dependent sampling function weights the importance of a trajectory based on the magnitude of its contribution to the time correlation function, and global trial moves are used to facilitate the efficient sampling the phase space of initial conditions. The method can be generally applied to sampling rare events efficiently while avoiding being trapped in a local region of the phase space. Results presented in the paper for two system-bath models demonstrate the efficiency of this new importance sampling method for full SC-IVR calculations.

Importância da intoxicação por Amorimia pubiflora (Malpighiaceae em bovinos em Mato Grosso: reprodução experimental da intoxicação em ovinos e bovinos

Directory of Open Access Journals (Sweden)

Marciel Becker

2013-09-01

folhas em brotação de A. pubiflora, é o princípio tóxico responsável pela "morte súbita" causada por Amorimia pubiflora. Esse estudo mostra a importância de A. pubiflora para a região Centro-Oeste do Brasil, principalmente para a pecuária bovina do município de Colniza, MT. Essa planta é tóxica, também, para ovinos e o quadro clínico é similar ao descrito para bovinos.

Decomposition and (importance) sampling techniques for multi-stage stochastic linear programs

Energy Technology Data Exchange (ETDEWEB)

Infanger, G.

1993-11-01

The difficulty of solving large-scale multi-stage stochastic linear programs arises from the sheer number of scenarios associated with numerous stochastic parameters. The number of scenarios grows exponentially with the number of stages and problems get easily out of hand even for very moderate numbers of stochastic parameters per stage. Our method combines dual (Benders) decomposition with Monte Carlo sampling techniques. We employ importance sampling to efficiently obtain accurate estimates of both expected future costs and gradients and right-hand sides of cuts. The method enables us to solve practical large-scale problems with many stages and numerous stochastic parameters per stage. We discuss the theory of sharing and adjusting cuts between different scenarios in a stage. We derive probabilistic lower and upper bounds, where we use importance path sampling for the upper bound estimation. Initial numerical results turned out to be promising.

Importância da avaliação sorológica pré-transfusional em receptores de sangue The importance of pre-transfusional serological screening in blood transfusion recipients

Directory of Open Access Journals (Sweden)

Cristina F. V. Carrazzone

2004-01-01

Full Text Available A triagem sorológica em doadores de sangue, não possibilita segurança de 100% quanto à possibilidade de transmissão de agentes infecto-contagiosos. O Ministério da Saúde determina a realização de testes para sífilis, hepatite B e C, HIV, doença de Chagas, HTLV I/II e malária nas áreas endêmicas, em todas as unidades de sangue coletadas no Brasil. A amostra do doador deve ficar armazenada por um período mínimo de seis meses. Com relação aos receptores de sangue, o Ministério determina a realização de testes imuno-hematológicos pré-transfusionais tais como classificação ABO/Rh, pesquisa de anticorpos irregulares e testes de compatibilidade. Nesse caso, a amostra do receptor deve ficar armazenada por um período de dez dias. Considerando que algumas patologias testadas, quando não detectadas no doador, podem ser transmitidas e cursar durante décadas sem apresentar sintomas, um estudo de provas entre receptores e seus respectivos doadores fica comprometido. Um recente estudo no Brasil, envolvendo receptores sem passado transfusional, eventual e politransfundidos mostrou uma importante prevalência de patologias que podem ser transmitidas pelo sangue. O estudo revelou também que uma elevada percentagem dos receptores que apresentaram reatividade não tinha conhecimento prévio à transfusão do seu estado sorológico. A segurança transfusional e a importância da aplicação de testes sorológicos em receptores de sangue antes da transfusão são pontos discutidos na presente revisão.The serological screening of blood donors does not constitute a 100% guarantee of protection against the possible transmission of infectious and contagious agents. The Ministry of Health determines that tests for syphilis, hepatitis B and C, Aids, Chagas' disease and HTLV I/II, as well as malaria in endemic areas, are mandatory in all the blood collection bags used in Brazil. The samples from blood donors must be stored for six months

Delineamento experimental e tamanho de amostra para alface cultivada em hidroponia Experimental design and sample size for hydroponic lettuce crop

Directory of Open Access Journals (Sweden)

Valéria Schimitz Marodim

2000-10-01

Full Text Available Este estudo visa a estabelecer o delineamento experimental e o tamanho de amostra para a cultura da alface (Lactuca sativa em hidroponia, pelo sistema NFT (Nutrient film technique. O experimento foi conduzido no Laboratório de Cultivos Sem Solo/Hidroponia, no Departamento de Fitotecnia da Universidade Federal de Santa Maria e baseou-se em dados de massa de plantas. Os resultados obtidos mostraram que, usando estrutura de cultivo de alface em hidroponia sobre bancadas de fibrocimento com seis canais, o delineamento experimental adequado é blocos ao acaso se a unidade experimental for constituída de faixas transversais aos canais das bancadas, e deve ser inteiramente casualizado se a bancada for a unidade experimental; para a variável massa de plantas, o tamanho da amostra é de 40 plantas para uma semi-amplitude do intervalo de confiança em percentagem da média (d igual a 5% e de 7 plantas para um d igual a 20%.This study was carried out to establish the experimental design and sample size for hydroponic lettuce (Lactuca sativa crop under nutrient film technique. The experiment was conducted in the Laboratory of Hydroponic Crops of the Horticulture Department of the Federal University of Santa Maria. The evaluated traits were plant weight. Under hydroponic conditions on concrete bench with six ducts, the most indicated experimental design for lettuce is randomised blocks for duct transversal plots or completely randomised for bench plot. The sample size for plant weight should be 40 and 7 plants, respectively, for a confidence interval of mean percentage (d equal to 5% and 20%.

Distribuzione e consistenza della popolazione di Scoiattolo grigio <em>Sciurus carolinensisem> Gmelin, 1788 nel levante genovese

Directory of Open Access Journals (Sweden)

Martina Venturini

2005-06-01

Full Text Available Abstract Distribution and population size of the Grey squirrel <em>Sciurus carolinensisem> Gmelin, 1788 in Province of Genova (NW Italy In Liguria, the Grey squirrel population originated from an introduction of five pairs in an urban park (Genoa Nervi in 1966. A first study, carried out in the 1996 by interviews, located a second group 3 km far, in Bogliasco locality. In this study, conducted in 2001-04, the population size of Genoa Nervi and the presence of the species in surrounding areas were investigated. In 2002 the population size was estimated in 115/286 individuals by distance sampling method, while, by direct observation, it varied from 80 individuals (2004 to 114 individuals (2003. The sampling by hair tubes in surrounding areas confirmed the presence of a group of grey squirrels in Bogliasco and excluded a further dispersal of the species. Riassunto In Liguria, la popolazione di Scoiattolo grigio <em>Sciurus carolinensisem> ha avuto origine dall'introduzione di 5 coppie nei parchi urbani di Genova Nervi nel 1966. Un primo studio condotto nel 1996 ha localizzato, tramite interviste, un secondo nucleo a 3 km di distanza, in località Bogliasco. Il presente studio, condotto nel 2001-2004, è stato finalizzato alla valutazione della consistenza della popolazione nei parchi di Nervi, mediante il metodo <em>distance sampling> e osservazioni dirette, e all'accertamento della presenza della specie nelle aree circostanti mediante l'utilizzo di <em>hair tubeem>. La stima della popolazione con il metodo <em>distance sampling> è risultata di 115/286 individui nel 2002, mentre quella ottenuta mediante osservazioni dirette è variata da 80 individui nel 2004 a 114 individui nel 2003. Gli accertamenti compiuti nelle aree circostanti i parchi di Nervi hanno consentito di confermare la presenza di un nucleo di scoiattoli a Bogliasco e di escludere un'ulteriore espansione della specie.

Estimation of functional failure probability of passive systems based on adaptive importance sampling method

International Nuclear Information System (INIS)

Wang Baosheng; Wang Dongqing; Zhang Jianmin; Jiang Jing

2012-01-01

In order to estimate the functional failure probability of passive systems, an innovative adaptive importance sampling methodology is presented. In the proposed methodology, information of variables is extracted with some pre-sampling of points in the failure region. An important sampling density is then constructed from the sample distribution in the failure region. Taking the AP1000 passive residual heat removal system as an example, the uncertainties related to the model of a passive system and the numerical values of its input parameters are considered in this paper. And then the probability of functional failure is estimated with the combination of the response surface method and adaptive importance sampling method. The numerical results demonstrate the high computed efficiency and excellent computed accuracy of the methodology compared with traditional probability analysis methods. (authors)

A importância da evolução do mobile advertising em função do desenvolvimento tecnológico

OpenAIRE

Lopes, Marta de Jesus Mourão

2016-01-01

Vivemos numa sociedade cada vez mais global, digital e dependente das novas tecnologias, que nos permitem estar conectados em qualquer parte do mundo. As marcas perceberam esta tendência e sentiram a necessidade de comunicar e acompanhar esta nova realidade. O mobile advertising é por isso um novo conceito que permite comunicar com um elevado número de pessoas, com a comunicação certa, no momento certo. O principal objetivo desta dissertação consiste em perceber as vantagens e importância ...

Monte Carlo importance sampling optimization for system reliability applications

International Nuclear Information System (INIS)

Campioni, Luca; Vestrucci, Paolo

2004-01-01

This paper focuses on the reliability analysis of multicomponent systems by the importance sampling technique, and, in particular, it tackles the optimization aspect. A methodology based on the minimization of the variance at the component level is proposed for the class of systems consisting of independent components. The claim is that, by means of such a methodology, the optimal biasing could be achieved without resorting to the typical approach by trials

A importância da gestão de marketing em empresa inovadora: estudo de empresa do Prime - Programa Primeira Empresa Inovadora

OpenAIRE

Zandberg, Michel do Carmo

2012-01-01

As pesquisas demonstram que empresas nascentes, mesmo aquelas que possuem produtos, processos ou serviços inovadores, novos ao mercado, têm muita dificuldade em permanecer com suas portas abertas nos primeiros dois anos, ou seja, a grande maioria das empresas encerra suas atividades antes de completar dois anos de existência. Diante deste fato, este estudo investiga a importância da gestão em Marketing nas empresas inovadoras com a finalidade de obter sucesso na inserção de produto, serviço o...

Evaluation of <em>HER2em> Gene Amplification in Breast Cancer Using Nuclei Microarray <em>in em>S>itu em>Hybridization

Directory of Open Access Journals (Sweden)

Xuefeng Zhang

2012-05-01

Full Text Available Fluorescence<em> em>>in situ em>hybridization (FISH assay is considered the “gold standard” in evaluating <em>HER2/neu (HER2em> gene status. However, FISH detection is costly and time consuming. Thus, we established nuclei microarray with extracted intact nuclei from paraffin embedded breast cancer tissues for FISH detection. The nuclei microarray FISH (NMFISH technology serves as a useful platform for analyzing <em>HER2em> gene/chromosome 17 centromere ratio. We examined <em>HER2em> gene status in 152 cases of invasive ductal carcinomas of the breast that were resected surgically with FISH and NMFISH. <em>HER2em> gene amplification status was classified according to the guidelines of the American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP. Comparison of the cut-off values for <em>HER2em>/chromosome 17 centromere copy number ratio obtained by NMFISH and FISH showed that there was almost perfect agreement between the two methods (κ coefficient 0.920. The results of the two methods were almost consistent for the evaluation of <em>HER2em> gene counts. The present study proved that NMFISH is comparable with FISH for evaluating <em>HER2em> gene status. The use of nuclei microarray technology is highly efficient, time and reagent conserving and inexpensive.

A importância da capacitação em saúde auditiva: uma revisão integrativa

Directory of Open Access Journals (Sweden)

Gisele Marques Ribeiro

2014-08-01

Full Text Available A presente pesquisa teve como objetivo verificar a produção científica, sobre capacitação em saúde auditiva nos últimos cinco anos. Trata-se de uma pesquisa exploratória nas bases de dados: MEDLINE, SciELO, LILACS. Foi realizada uma revisão integrativa da literatura publicada no período de 2007 a 2011, utilizando os descritores: Audição, Deficiência Auditiva, Hipoacusia, Perda Auditiva, Perda da Audição, Perda da Capacidade Auditiva, Pessoas com Deficiência Auditiva, Portadores de Deficiência Auditiva, Portadores de Insuficiência Auditiva, Portadores de Surdez, combinadas com: Capacitação, Capacitação em Serviço, Programa Saúde da Família, Capacitação de Recursos Humanos em Saúde.Foram encontrados 31 artigos e selecionados cinco, que contemplavam a temática pesquisada. Destes, três eram direcionados aos Agentes Comunitários de Saúde que atuavam em Equipes de Saúde da Família, para verificar a efetividade das capacitações em relação à saúde auditiva infantil, e dois trabalhadores de empresas, para sensibilizar os profissionais sobre a prevenção das alterações auditivas nas atividades profissionais. Dois estudos com os Agentes Comunitários de Saúde utilizaram a videoconferência e a capacitação presencial simultaneamente e outro somente presencial. Observou-se que a videoconferência é um meio que pode proporcionar a disseminação do conhecimento, no entanto deve ser utilizada de uma forma complementar. Nos estudos com trabalhadores verificou-se que as capacitações devem ser permanentes e enfocar mais o uso, manuseio e conservação dos protetores auditivos. As publicações confirmam a efetividade das capacitações, porém, há poucos trabalhos nesta área, o que vem reforçar a importância de novas pesquisas com enfoque na educação em saúde auditiva.

Food and feed safety assessment: the importance of proper sampling.

Science.gov (United States)

Kuiper, Harry A; Paoletti, Claudia

2015-01-01

The general principles for safety and nutritional evaluation of foods and feed and the potential health risks associated with hazardous compounds are described as developed by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) and further elaborated in the European Union-funded project Safe Foods. We underline the crucial role of sampling in foods/feed safety assessment. High quality sampling should always be applied to ensure the use of adequate and representative samples as test materials for hazard identification, toxicological and nutritional characterization of identified hazards, as well as for estimating quantitative and reliable exposure levels of foods/feed or related compounds of concern for humans and animals. The importance of representative sampling is emphasized through examples of risk analyses in different areas of foods/feed production. The Theory of Sampling (TOS) is recognized as the only framework within which to ensure accuracy and precision of all sampling steps involved in the field-to-fork continuum, which is crucial to monitor foods and feed safety. Therefore, TOS must be integrated in the well-established FAO/WHO risk assessment approach in order to guarantee a transparent and correct frame for the risk assessment and decision making process.

Improved importance sampling technique for efficient simulation of digital communication systems

Science.gov (United States)

Lu, Dingqing; Yao, Kung

1988-01-01

A new, improved importance sampling (IIS) approach to simulation is considered. Some basic concepts of IS are introduced, and detailed evolutions of simulation estimation variances for Monte Carlo (MC) and IS simulations are given. The general results obtained from these evolutions are applied to the specific previously known conventional importance sampling (CIS) technique and the new IIS technique. The derivation for a linear system with no signal random memory is considered in some detail. For the CIS technique, the optimum input scaling parameter is found, while for the IIS technique, the optimum translation parameter is found. The results are generalized to a linear system with memory and signals. Specific numerical and simulation results are given which show the advantages of CIS over MC and IIS over CIS for simulations of digital communications systems.

Generation of a Highly Reactive Chicken-Derived Single-Chain Variable Fragment against <em>Fusarium verticillioidesem> by Phage Display

Directory of Open Access Journals (Sweden)

Zu-Quan Hu

2012-06-01

Full Text Available <em>Fusarium> <em>verticillioides> is the primary causal agent of Fusarium ear and kernel rot in maize, producing fumonisin mycotoxins that are toxic to humans and domestic animals. Rapid detection and monitoring of fumonisin-producing fungi are pivotally important for the prevention of mycotoxins from entering into food/feed products. Chicken-derived single-chain variable fragments (scFvs against cell wall-bound proteins from <em>F. verticillioidesem> were isolated from an immunocompetent phage display library. Comparative phage enzyme-linked immunosorbant assays (ELISAs and sequencing analyses identified four different scFv antibodies with high sensitivity. Soluble antibody ELISAs identified two highly sensitive scFv antibodies, FvCA3 and FvCA4, with the latter being slightly more sensitive. Three-dimensional modeling revealed that the FvCA4 may hold a better overall structure with CDRH3, CDRL1 and CDRL3 centered in the core region of antibody surface compared with that of other scFvs. Immunofluorescence labeling revealed that the binding of FvCA4 antibody was localized to the cell walls of conidiospores and hyphae of <em>F. verticillioidesem>, confirming the specificity of this antibody for a surface target. This scFv antibody was able to detect the fungal mycelium as low as 10⁻² μg/mL and contaminating mycelium at a quantity of 10⁻² mg/g maize. This is the first report that scFv antibodies derived from phage display have a wide application for rapid and accurate detection and monitoring of fumonisin-producing pathogens in agricultural samples.

An Importance Sampling Simulation Method for Bayesian Decision Feedback Equalizers

OpenAIRE

Chen, S.; Hanzo, L.

2000-01-01

An importance sampling (IS) simulation technique is presented for evaluating the lower-bound bit error rate (BER) of the Bayesian decision feedback equalizer (DFE) under the assumption of correct decisions being fed back. A design procedure is developed, which chooses appropriate bias vectors for the simulation density to ensure asymptotic efficiency of the IS simulation.

Roost selection by barbastelle bats (<em>Barbastella barbastellusem>, Chiroptera: Vespertilionidae in beech woodlands of central Italy

Directory of Open Access Journals (Sweden)

Danilo Russo

2003-10-01

Full Text Available The barbastelle bat, <em>Barbastella barbastellusem> (Schreber, 1774 is a medium-sized, tree-dwelling vespertilionid classified as ?Endangered? in Italy; in western Europe it may be one of the rarest bat species. <em>B. barbastellusem> shows roosting preferences that should be regarded as a key point in conservation protocols. We examined roost selection in a breeding population of <em>B. barbastellusem> from the Abruzzo Lazio and Molise National Park (central Italy at three levels: woodland structure and management type; tree characteristics; and cavity characteristics. In 2001-2002, we fitted 31 adult <em>B. barbastellusem> (29 lactating females, one pregnant female and one male with 0.48g radio-tags and tracked them to their roost-trees. The bats were tracked for 4.5 ± 3.7 days (range: 0-12 days. We located 33 roosts used by 25 subjects (1.8±1.2 roosts/bat, range 1-5. The bats switched roosts frequently: 13 bats used more than one tree over the study period. A chi-square analysis showed that the roosts were not distributed at random across woodland categories: unmanaged woodland was positively selected, whereas shelterwood-harvested woodland was used in proportion to its availability, and ?pastures+scattered trees? was avoided. Twenty out of 33 roost trees were dead <em>Fagus sylvaticaem> trees; conversely, living <em>F. sylvaticaem> dominated in a tree sample obtained at random; dead trees were used more than expected (Χ² test, <em>P> <0.001. Overall, roost trees were significantly taller and had a larger diameter at breast?s height and more cavities than random trees; they also had a lower percent canopy closure than random trees. To highlight which variables were actually associated with selection, we devised a logistic regression model. The full model was significant (<em>P> <0.001; removal of tree type and tree height affected the model significantly, but the other variables did not produce detectable effects. The

Amostragem domiciliar contínua em estudos epidemiológicos e no ensino Continuous household sampling for epidemiological research and for teaching purposes

Directory of Open Access Journals (Sweden)

José da Rocha Carvalheiro

1979-09-01

Full Text Available Descreve-se um sistema contínuo de levantamento de condições de saúde, por entrevistas domiciliárias, operando em Ribeirão Preto (SP desde 1974. Comentam-se as vantagens quanto à sua utilização na investigação de problemas específicos surgidos nesse período, bem como a sua utilização no ensino.The use of adequate populational-base survey is frequently impossible in epidemiological studies. Special studies are made among particular groups of individuals to investigate simultaneously the presence of both the factor and the disease. In these studies it is obviously important to use adequate sampling techniques. A system of continuous household sampling is described, designed to perform, simultaneously, epidemiological research, health system monitoring and to serve as a basis for courses on sampling techniques and epidemiological methods. In the municipality of Ribeirão Preto, S. Paulo, Brazil a household sampling system has been in operation since 1974, using a master sample of 8500 households. Every two weeks, 380 households are visited and information is gathered about diseases, accidents, and the use of health services. Special epidemiological research is introduced when necessary. Future development includes the use of standardized questionnaires and physical and laboratory examinations of the people interviewed.

Optimum size in grid soil sampling for variable rate application in site-specific management Tamanho ideal em grades de amostragem de solos para aplicação em taxa variável em manejo localizado

Directory of Open Access Journals (Sweden)

Marcos Rafael Nanni

2011-06-01

Full Text Available The importance of understanding spatial variability of soils is connected to crop management planning. This understanding makes it possible to treat soil not as a uniform, but a variable entity, and it enables site-specific management to increase production efficiency, which is the target of precision agriculture. Questions remain as the optimum soil sampling interval needed to make site-specific fertilizer recommendations in Brazil. The objectives of this study were: i to evaluate the spatial variability of the main attributes that influence fertilization recommendations, using georeferenced soil samples arranged in grid patterns of different resolutions; ii to compare the spatial maps generated with those obtained with the standard sampling of 1 sample ha-1, in order to verify the appropriateness of the spatial resolution. The attributes evaluated were phosphorus (P, potassium (K, organic matter (OM, base saturation (V% and clay. Soil samples were collected in a 100 × 100 m georeferenced grid. Thinning was performed in order to create a grid with one sample every 2.07, 2.88, 3.75 and 7.20 ha. Geostatistical techniques, such as semivariogram and interpolation using kriging, were used to analyze the attributes at the different grid resolutions. This analysis was performed with the Vesper software package. The maps created by this method were compared using the kappa statistics. Additionally, correlation graphs were drawn by plotting the observed values against the estimated values using cross-validation. P, K and V%, a finer sampling resolution than the one using 1 sample ha-1 is required, while for OM and clay coarser resolutions of one sample every two and three hectares, respectively, may be acceptable.A importância de compreender a variabilidade espacial do solo está conectada ao planejamento do manejo das culturas. Este entendimento faz com que seja possível tratar o solo não como uma entidade uniforme, mas variável, e permite o

A hybrid reliability algorithm using PSO-optimized Kriging model and adaptive importance sampling

Science.gov (United States)

Tong, Cao; Gong, Haili

2018-03-01

This paper aims to reduce the computational cost of reliability analysis. A new hybrid algorithm is proposed based on PSO-optimized Kriging model and adaptive importance sampling method. Firstly, the particle swarm optimization algorithm (PSO) is used to optimize the parameters of Kriging model. A typical function is fitted to validate improvement by comparing results of PSO-optimized Kriging model with those of the original Kriging model. Secondly, a hybrid algorithm for reliability analysis combined optimized Kriging model and adaptive importance sampling is proposed. Two cases from literatures are given to validate the efficiency and correctness. The proposed method is proved to be more efficient due to its application of small number of sample points according to comparison results.

Adaptive importance sampling for probabilistic validation of advanced driver assistance systems

NARCIS (Netherlands)

Gietelink, O.J.; Schutter, B. de; Verhaegen, M.

2006-01-01

We present an approach for validation of advanced driver assistance systems, based on randomized algorithms. The new method consists of an iterative randomized simulation using adaptive importance sampling. The randomized algorithm is more efficient than conventional simulation techniques. The

Distribuição espacial e plano de amostragem de Calacarus heveae (Acari em seringueira Spatial distribution and sampling plan for Calacarus heveae (Acari on rubber trees

Directory of Open Access Journals (Sweden)

Noeli Juarez Ferla

2007-12-01

Full Text Available Calacarus heveae Feres, 1992 é um eriofídeo descrito de espécimes coletados em plantas de seringueira (Hevea brasiliensis, Euphorbiaceae na região noroeste do Estado de São Paulo. Esse ácaro prefere a face adaxial dos folíolos e pode causar a perda do brilho, amarelecimento, bronzeamento dessa região e a subseqüente queda prematura das folhas. O objetivo deste trabalho foi analisar a distribuição de C. heveae em seringueira, selecionar a unidade de amostragem mais representativa e desenvolver um plano de amostragem para o estudo de sua flutuação populacional. O trabalho foi conduzido com os clones PB 260 e IAN 873, respectivamente nos municípios de Itiquira e de Pontes e Lacerda, ambos no Mato Grosso. Em Itiquira, diferenças significativas foram observadas em quatro ocasiões em relação ao número médio de ácaros por folha nos diferentes estratos das plantas. Nas amostragens realizadas em Pontes e Lacerda, nenhuma diferença significativa foi encontrada entre os estratos em relação àquele parâmetro. Apenas em Itiquira, em uma ocasião de amostragem, foi verificada diferença entre os três estratos, em relação à proporção de folhas infestadas. Nenhuma diferença significativa foi verificada em relação ao número médio de ácaros por folha e proporção de folhas infestadas por C. heveae a diferentes distâncias da periferia da copa. Calacarus heveae exibe distribuição agregada no campo. Para estimar a densidade de C. heveae, um plano numérico e um plano binomial de amostragem foram desenvolvidos.Calacarus heveae Feres, 1992 (Eriophyidae is a mite described from specimens collected on rubber tree (Hevea brasiliensis, Euphorbiaceae in the northwest region of the state of São Paulo. This mite prefers the adaxial face of the folioles which it can turn dry, yellowish and brownish; it can also cause leaf fall. The aim of this work was to analyze the distribution of C. heveae on rubber trees, to select the most

Identification of <em>Colletotrichum> species causing anthracnose on Tahiti lime, tree tomato and mango

Directory of Open Access Journals (Sweden)

Martínez Erika P.

2009-08-01

Full Text Available

In Colombia, citrus, tree tomato and mango crops are likely to suffer considerable losses from anthracnose caused by several <em>Colletotrichum> species, which were identified by the present study on infected organs of the three fruit crops, sampled in different regions of the country. Identification was based on their morphological and molecular characteristics, as well as on fungicide (benomyl and copper hydroxide sensitivity and pathogenicity tests. The latter assessed infectivity on both the original hosting crop and the other two crops (crossed infection, by putting the fungi in contact with organs taken from the three fruit crops. Molecular identification of the <em>Colletotrichum> species was carried out through amplification of rDNA ITS regions by means of <em>C. gloeosporioidesem> (CgInt and <em>C. acutatumem> (CaInt2 specific primer PCR combining the use of ITS4 universal primer. The results indicate that <em>C. acutatumem> is the infectious agent in Tahiti lime and tree tomato, and so is <em>C. gloeosporioidesem> in mango. Although <em>C. acutatumem> is the infectious agent in two diferent fruit species, the strains proved to be specific of their original hosts.

Non-parametric adaptive importance sampling for the probability estimation of a launcher impact position

International Nuclear Information System (INIS)

Morio, Jerome

2011-01-01

Importance sampling (IS) is a useful simulation technique to estimate critical probability with a better accuracy than Monte Carlo methods. It consists in generating random weighted samples from an auxiliary distribution rather than the distribution of interest. The crucial part of this algorithm is the choice of an efficient auxiliary PDF that has to be able to simulate more rare random events. The optimisation of this auxiliary distribution is often in practice very difficult. In this article, we propose to approach the IS optimal auxiliary density with non-parametric adaptive importance sampling (NAIS). We apply this technique for the probability estimation of spatial launcher impact position since it has currently become a more and more important issue in the field of aeronautics.

Adaptive importance sampling of random walks on continuous state spaces

International Nuclear Information System (INIS)

Baggerly, K.; Cox, D.; Picard, R.

1998-01-01

The authors consider adaptive importance sampling for a random walk with scoring in a general state space. Conditions under which exponential convergence occurs to the zero-variance solution are reviewed. These results generalize previous work for finite, discrete state spaces in Kollman (1993) and in Kollman, Baggerly, Cox, and Picard (1996). This paper is intended for nonstatisticians and includes considerable explanatory material

Numerically Accelerated Importance Sampling for Nonlinear Non-Gaussian State Space Models

NARCIS (Netherlands)

Koopman, S.J.; Lucas, A.; Scharth, M.

2015-01-01

We propose a general likelihood evaluation method for nonlinear non-Gaussian state-space models using the simulation-based method of efficient importance sampling. We minimize the simulation effort by replacing some key steps of the likelihood estimation procedure by numerical integration. We refer

Sampling high-altitude and stratified mating flights of red imported fire ant.

Science.gov (United States)

Fritz, Gary N; Fritz, Ann H; Vander Meer, Robert K

2011-05-01

With the exception of an airplane equipped with nets, no method has been developed that successfully samples red imported fire ant, Solenopsis invicta Buren, sexuals in mating/dispersal flights throughout their potential altitudinal trajectories. We developed and tested a method for sampling queens and males during mating flights at altitudinal intervals reaching as high as "140 m. Our trapping system uses an electric winch and a 1.2-m spindle bolted to a swiveling platform. The winch dispenses up to 183 m of Kevlar-core, nylon rope and the spindle stores 10 panels (0.9 by 4.6 m each) of nylon tulle impregnated with Tangle-Trap. The panels can be attached to the rope at various intervals and hoisted into the air by using a 3-m-diameter, helium-filled balloon. Raising or lowering all 10 panels takes approximately 15-20 min. This trap also should be useful for altitudinal sampling of other insects of medical importance.

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

Importance Sampling Simulation of Population Overflow in Two-node Tandem Networks

NARCIS (Netherlands)

Nicola, V.F.; Zaburnenko, T.S.; Baier, C; Chiola, G.; Smirni, E.

2005-01-01

In this paper we consider the application of importance sampling in simulations of Markovian tandem networks in order to estimate the probability of rare events, such as network population overflow. We propose a heuristic methodology to obtain a good approximation to the 'optimal' state-dependent

The use of importance sampling in a trial assessment to obtain converged estimates of radiological risk

International Nuclear Information System (INIS)

Johnson, K.; Lucas, R.

1986-12-01

In developing a methodology for assessing potential sites for the disposal of radioactive wastes, the Department of the Environment has conducted a series of trial assessment exercises. In order to produce converged estimates of radiological risk using the SYVAC A/C simulation system an efficient sampling procedure is required. Previous work has demonstrated that importance sampling can substantially increase sampling efficiency. This study used importance sampling to produce converged estimates of risk for the first DoE trial assessment. Four major nuclide chains were analysed. In each case importance sampling produced converged risk estimates with between 10 and 170 times fewer runs of the SYVAC A/C model. This increase in sampling efficiency can reduce the total elapsed time required to obtain a converged estimate of risk from one nuclide chain by a factor of 20. The results of this study suggests that the use of importance sampling could reduce the elapsed time required to perform a risk assessment of a potential site by a factor of ten. (author)

Amostras complexas em inquéritos populacionais: planejamento e implicações na análise estatística dos dados Complex Sampling Design in Population Surveys: Planning and effects on statistical data analysis

Directory of Open Access Journals (Sweden)

Célia Landmann Szwarcwald

2008-05-01

Full Text Available A avaliação do desempenho dos sistemas de saúde das nações vem ganhando importância crescente entre os gestores do setor saúde. Entre os instrumentais de avaliação do desempenho de saúde, destacam-se os inquéritos nacionais de saúde, cada vez mais utilizados para avaliar o estado de saúde da população e a assistência de saúde prestada do ponto de vista do usuário. A maioria dos inquéritos nacionais de saúde não usa amostragem aleatória simples, em parte por restrições orçamentárias, em parte por limites de tempo associado à coleta de dados. Em geral, utiliza-se combinação de vários métodos probabilísticos de amostragem para seleção de uma amostra representativa da população, chamada de desenho complexo de amostragem. Entre os métodos de amostragem mais utilizados conjuntamente, destacam-se a amostra aleatória simples, a amostragem estratificada, e a amostragem por conglomerados. Resultante desse processo, a preocupação subseqüente é a análise de dados provenientes de amostras complexas. Este artigo trata de questões relacionadas à análise estatística de dados obtidos através de pesquisas com desenhos complexos de amostragem. Apresentam-se os problemas que ocorrem quando a análise estatística não incorpora a estrutura do plano amostral. Ao ignorar o desenho de amostragem, a análise estatística tradicional, sob a suposição de amostragem aleatória simples, pode produzir incorreções tanto para as estimativas médias como para as respectivas variâncias, comprometendo os resultados, os testes de hipóteses e as conclusões da pesquisa. Para a exemplificação dos métodos, é utilizada a Pesquisa Mundial de Saúde (PMS, realizada no Brasil em 2003.The evaluation of the health systems of nations has been gaining increasing importance among health managers. Among the evaluation tools for the performance of health systems, nationwide health surveys have been more and more used to evaluate the

Importance of interrelation carbohydrate and protein in diets of ruminants/ Importância da inter-relação carboidrato e proteína em dietas de ruminantes

Directory of Open Access Journals (Sweden)

Andréa Pereira Pinto

2005-06-01

Full Text Available This literature review had as objective to relate the importance of the carbohydrate and protein synchronization in ruminant diets. The nutritional requirements systems to ruminant that give support to the diets formulations, require that the feeds commonly used in the feeding are fractional for best characterize them. Along the years there was considerable progress in the ruminant nutrition, but that progress, most of the time, was based on empiric determinations that not respected the multiple microbial interrelations and they considered the ruminal ecosystem are very complex and not understood.Esta revisão de literatura teve como objetivo relacionar a importância da sincronização de carboidratos e proteínas em dietas de ruminantes, pois os sistemas de exigências nutricionais de ruminantes que dão suporte às formulações de rações exigem que os alimentos comumente utilizados na alimentação sejam fracionados no sentido de melhor caracterizá-los. Ao longo dos anos houve considerável avanço na nutrição dos ruminantes, mas esse progresso, na maioria das vezes, foi baseado em determinações empíricas que desconsideravam as múltiplas inter-relações microbianas e consideravam o ecossistema ruminal muito complexo e não compreendido.

Concentrações de metais pesados em grãos de café produzidos em lavouras sobre solos originados do basalto e do arenito Caiuá Heavy metals concentration in coffee grains produced in farming under basalt and Caiuá sandstone soils

Directory of Open Access Journals (Sweden)

Carla Adriana Pizarro Schmidt

2009-08-01

Full Text Available Tendo em vista que o Brasil é um grande produtor e consumidor de café, fica evidente a importância de sua caracterização em diferentes locais de cultivo. O objetivo do presente estudo foi quantificar os teores de metais pesados em amostras de grãos de café, provenientes de lavouras implantadas em solos oriundos do basalto e do arenito Caiuá do Estado do Paraná. Foram examinadas 30 amostras de grãos de café, sendo 15 cultivados em solos predominantemente arenosos e 15 em solos argilosos. A determinação de Cromo (Cr, Cobalto (Co, Níquel (Ni, Chumbo (Pb, Cádmio (Cd, Cobre (Cu, Zinco (Zn e Manganês (Mn foi feita por espectrometria de emissão atômica com fonte de plasma induzido com Thermo Jarrel-ash ICAP 612 E (ICP-EAS. Os níveis foram variáveis entre as amostras.Considering that Brazil is a big producer and coffee consumer its evident the importance of its characterization in the different places of cultivation. The purpose of the present study was quantify the levels of high metals in coffee grains samples 'IAPAR 59' derived from farming introduced in basalt and Caiuá sandstone soils in Paraná, Brazil . Thirty ground samples were examined, being 15 of predominantly arenaceous ground and 15 of argillaceous ground. The determination of Chrome (Cr, Cobalt (Co, Nickel (Ni, Lead (Pb, Cadmium (Cd, Copper (Cu, Zinc (Zn and Manganese (Mn, was made through atomic emission spectrometry with induced plasma source with Thermo 612 Jarrel-ash ICAP E (ICP-EAS. The levels changed among the samples.

Action of Chitosan Against <em>Xanthomonas> Pathogenic Bacteria Isolated from <em>Euphorbia pulcherrimaem>

Directory of Open Access Journals (Sweden)

Yanli Wang

2012-06-01

Full Text Available The antibacterial activity and mechanism of two kinds of chitosan were investigated against twelve <em>Xanthomonas> strains recovered from <em>Euphorbia pulcherrimaem>. Results indicated that both chitosans markedly inhibited bacterial growth based on OD loss. Furthermore, the release of DNA and RNA from three selected strains was increased by both chitosans. However, the release of intracellular proteins was inhibited by both chitosans at different concentration and incubation times, except chitosan A at 0.1 mg/mL for 0.5 h incubation and 0.2 mg/mL for 2.0 h incubation increased the release of proteins, indicating the complexity of the interaction and cell membranes, which was affected by incubation time, bacterial species, chitosan type and concentration. Transmission electron microscopic observations revealed that chitosan caused changes in protoplast concentration and surface morphology. In some cells, the membranes and walls were badly distorted and disrupted, while other cells were enveloped by a thick and compact ribbon-like layer. The contrary influence on cell morphology may explain the differential effect in the release of material. In addition, scanning electron microscope and biofilm formation test revealed that both chitosans removed biofilm biomass. Overall, this study showed that membrane and biofilm play an important role in the antibacterial mechanism of chitosan.

Allometric and Isometric variations in the Italian <em>Apodemus sylvaticusem> and <em>Apodemus flavicollisem> with respect to the conditions of allopatry and sympatry / Variazioni allometriche e isometriche in <em>Apodemus sylvaticusem> e <em>Apodemus flavicollisem> italiani, rispetto alle condizioni di allopatria e simpatria

Directory of Open Access Journals (Sweden)

Giovanni Amori

1986-12-01

thickness and positively linked to skull length is allometric. The intraspecific comparison perhaps reflects a gradient of skull length, whereas the interspecific one a difference in size and thickness between <em>A. sylvaticusem> and <em>A. flavicollisem> skull. On the other hand it appears, from Filippucci et al. (1984 that the importance of genetical factors is highly dependent on the particular character examined and on the species under study. In such a manner, results which are ecologically rather similar could be obtained with different processes. Conversely, the isometry and allopatry of characters seems to depend on different ways from the taxonomical, evolutive and ecologica1 context taken into account. Namely, some characters seem to be more subject to the competitive pressure, others to the genera1 structural model of the species. On the other hand, it is not sure that competition can explain all the observed phenomena, some of which may have a multiple base. More research is needed in order to elucidate such casual aspects of observed phenomena. Riassunto Su <em>Apodemus sylvaticusem> dell'Italia insulare e su <em>A. sylvaticusem> ed <em>Apodemus flavicollisem> dell'Italia peninsulare sono stati studiati alcuni caratteri cranici, evidenziandone l'isometria o l'allometria. Su detti caratteri sono stati verificati e discussi i modelli eco1ogici: variazione di nicchia, spostamento dei caratteri, convergenza fenotipica e parallelismo di caratteri in condizione di simpatria e/o allopatria.

Use of nuclear technique in samples for agricultural purposes Uso de técnica nuclear em amostras de interesse na agricultura

Directory of Open Access Journals (Sweden)

Kerley A. P. de Oliveira

2013-02-01

Full Text Available The concern related to environment is growing. Due to this, it is needed to determine chemical elements in a large range of concentration. The neutron activation technique (NAA determines the elemental composition by the measurement of artificial radioactivity in a sample that was submitted to a neutron flux. NAA is a sensitive and accurate technique with low detection limits. An example of application of NAA was the measurement of concentrations of rare earth elements (REE in waste samples of phosphogypsum (PG and cerrado soil samples (clayey and sandy soils. Additionally, a soil reference material of the International Atomic Energy Agency (IAEA was also analyzed. The REE concentration in PG samples was two times higher than those found in national fertilizers, (total of 4,000 mg kg-1 , 154 times greater than the values found in the sandy soil (26 mg kg-1 and 14 times greater than the in clayey soil (280 mg kg-1 . The experimental results for the reference material were inside the uncertainty of the certified values pointing out the accuracy of the method (95%. The determination of La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Lu in the samples and reference material confirmed the versatility of the technique on REE determination in soil and phosphogypsum samples that are matrices for agricultural interest.A preocupação crescente com o meio ambiente leva à necessidade de serem determinados elementos químicos em faixas de concentração cada vez mais largas. Entre as técnicas existentes, está a ativação neutrônica (AAN, que determina a composição química elementar por meio da medida da radioatividade artificial induzida ao se submeter uma amostra a um fluxo de nêutrons. A AAN possui alta sensibilidade, exatidão, precisão e natureza não destrutiva (dispensa tratamento químico prévio. Como exemplo de aplicação da técnica, elementos terras raras (ETR foram determinados em amostras do resíduo fosfogesso (PG e de solo

Plano amostral em parcelas de milho para avaliação de atributos de espigas Sampling plan in corn plots to evaluate ear characteristics

Directory of Open Access Journals (Sweden)

Thomas Newton Martin

2005-12-01

Full Text Available Em experimentos agrícolas, a amostragem é importante para reduzir os custos e a mão-de-obra, embora devam possuir características que confiram precisão experimental adequada. O objetivo do trabalho foi determinar uma metodologia para se amostrar parcelas e sub-parcelas experimentais de milho, quando o objetivo é avaliar atributos morfológicos e de rendimento avaliados nas espigas. O experimento foi realizado, no Departamento de Fitotecnia da Universidade Federal de Santa Maria, com quatro bases genéticas de milho (híbrido simples - DAS 9560; híbrido duplo - AG 303; híbrido triplo - AG 6018; variedade cultivada - BR 202. O delineamento usado foi blocos completos casualizados com quatro repetições. A parcela foi constituída de 96 sub-parcelas de um metro. Em cada parcela, amostraram-se as espigas de cinco sub-parcelas. Foram avaliados o comprimento, o diâmetro, o rendimento de grãos e a massa de cem grãos de cada espiga. Concluiu-se que o tamanho da amostra nas parcelas de milho está relacionado ao atributo a ser avaliado nas espigas. Existem interferências genéticas e ambientais sobre a magnitude da estimativa do tamanho da amostra de espigas de milho. Pode-se amostrar 24 espigas por parcela, em seis repetições por genótipo, para avaliar os atributos comprimento e largura de espigas, rendimento de grãos e massa de cem grãos, para obter uma semi-amplitude do intervalo de confiança abaixo de 10% da média.In agricultural experiments good sampling techniques are important to reduce costs and labor, and guarantee adequate experimental precision. The objective of this research was to study a sampling methodology of experimental plots to evaluate morphologic characteristic and corn yield in maize spikes. Single (DAS 9560, double (AG 6018 and triple (AG 303 crosses corn hybrids and an open pollinated variety (BR 202 were ev aluated. The experiment design was a randomized complete block with four replications and was conducted

Towards a universal sampling protocol for soil biotas in the humid tropics Em direção a um protocolo universal de amostragem de biotas do solo nos trópicos úmidos

Directory of Open Access Journals (Sweden)

David Edward Bignell

2009-08-01

Full Text Available This paper reviews the methods for the inventory of below-ground biotas in the humid tropics, to document the (hypothesized loss of soil biodiversity associated with deforestation and agricultural intensification at forest margins. The biotas were grouped into eight categories, each of which corresponded to a major functional group considered important or essential to soil function. An accurate inventory of soil organisms can assist in ecosystem management and help sustain agricultural production. The advantages and disadvantages of transect-based and grid-based sampling methods are discussed, illustrated by published protocols ranging from the original "TSBF transect", through versions developed for the alternatives to Slash-and-Burn Project (ASB to the final schemes (with variants adopted by the Conservation and Sustainable Management of Below-ground Biodiversity Project (CSM-BGBD. Consideration is given to the place and importance of replication in below-ground biological sampling and it is argued that the new sampling protocols are inclusive, i.e. designed to sample all eight biotic groups in the same field exercise; spatially scaled, i.e. provide biodiversity data at site, locality, landscape and regional levels, and link the data to land use and land cover; and statistically robust, as shown by a partial randomization of plot locations for sampling.Este trabalho faz uma revisão dos métodos de inventariado da biota edáfica nos trópicos úmidos para documentar a (hipotética perda de biodiversidade do solo associada ao desmatamento e à intensificação agrícola nas margens de florestas. A biota foi agrupada em oito categorias, cada uma correspondente a um grande grupo funcional considerado importante ou essencial para a função do solo. Um inventário cuidadoso dos organismos do solo pode auxiliar a gestão de ecossistemas e a sustentabilidade da produção agrícola. As vantagens e desvantagens de métodos de amostragem baseados em

A specimen of <em>Sorex> cfr. <em>samniticus> in Barn Owl's pellets from Murge plateau (Apulia, Italy / Su di un <em>Sorex> cfr. <em>samniticus> (Insectivora, Soricidae rinvenuto in borre di <em>Tyto albaem> delle Murge (Puglia, Italia

Directory of Open Access Journals (Sweden)

Giovanni Ferrara

1992-07-01

Full Text Available Abstract In a lot of Barn Owl's pellets from the Murge plateau a specimen of <em>Sorex> sp. was detected. Thank to some morphological and morphometrical features, the cranial bones can be tentatively attributed to <em>Sorex samniticusem> Altobello, 1926. The genus <em>Sorex> was not yet included in the Apulia's fauna southwards of the Gargano district; the origin and significance of the above record is briefly discussed, the actual presence of a natural population of <em>Sorex> in the Murge being not yet proved. Riassunto Viene segnalato il rinvenimento di un esemplare di <em>Sorex> cfr. <em>samniticus> da borre di <em>Tyto albaem> delle Murge. Poiché il genere non era stato ancora segnalato nella Puglia a sud del Gargano, viene discusso il significato faunistico del reperto.

Efecto de extractos vegetales de <em>Polygonum hydropiperoidesem>, <em>Solanum nigrumem> y <em>Calliandra pittieriem> sobre el gusano cogollero (<em>Spodoptera frugiperdaem>

Directory of Open Access Journals (Sweden)

Lizarazo H. Karol

2008-12-01

Full Text Available

El gusano cogollero <em>Spodoptera frugiperdaem> es una de las plagas que más afectan los cultivos en la región de Sumapaz (Cundinamarca, Colombia. En la actualidad se controla principalmente aplicando productos de síntesis química, sin embargo la aplicación de extractos vegetales surge como una alternativa de menor impacto sobre el ambiente. Este control se emplea debido a que las plantas contienen metabolitos secundarios que pueden inhibir el desarrollo de los insectos. Por tal motivo, la presente investigación evaluó el efecto insecticida y antialimentario de extractos vegetales de barbasco <em>Polygonum hydropiperoidesem> (Polygonaceae, carbonero <em>Calliandra pittieriem> (Mimosaceae y hierba mora <em>Solanum nigrumem> (Solanaceae sobre larvas de <em>S. frugiperdaem> biotipo maíz. Se estableció una cría masiva del insecto en el laboratorio utilizando una dieta natural con hojas de maíz. Posteriormente se obtuvieron extractos vegetales utilizando solventes de alta polaridad (agua y etanol y media polaridad (diclorometano los cuales se aplicaron sobre las larvas de segundo instar. Los resultados más destacados se presentaron con extractos de <em>P. hydropiperoidesem>, obtenidos con diclorometano en sus diferentes dosis, con los cuales se alcanzó una mortalidad de 100% 12 días después de la aplicación y un efecto antialimentario representado por un consumo de follaje de maíz inferior al 4%, efectos similares a los del testigo comercial (Clorpiriphos.

Importance Sampling for Failure Probabilities in Computing and Data Transmission

DEFF Research Database (Denmark)

Asmussen, Søren

We study efficient simulation algorithms for estimating P(Χ > χ), where Χ is the total time of a job with ideal time T that needs to be restarted after a failure. The main tool is importance sampling where one tries to identify a good importance distribution via an asymptotic description...... of the conditional distribution of T given Χ > χ. If T ≡ t is constant, the problem reduces to the efficient simulation of geometric sums, and a standard algorithm involving a Cramér type root  γ(t) is available. However, we also discuss  an algorithm avoiding the rootfinding. If T is random, particular attention...... is given to T having either a gamma-like tail or a regularly varying tail, and to failures at Poisson times. Different type of conditional limits occur, in particular exponentially tilted Gumbel distributions and Pareto distributions. The algorithms based upon importance distributions for T using...

Importance sampling for failure probabilities in computing and data transmission

DEFF Research Database (Denmark)

Asmussen, Søren

2009-01-01

In this paper we study efficient simulation algorithms for estimating P(X›x), where X is the total time of a job with ideal time $T$ that needs to be restarted after a failure. The main tool is importance sampling, where a good importance distribution is identified via an asymptotic description...... of the conditional distribution of T given X›x. If T≡t is constant, the problem reduces to the efficient simulation of geometric sums, and a standard algorithm involving a Cramér-type root, γ(t), is available. However, we also discuss an algorithm that avoids finding the root. If T is random, particular attention...... is given to T having either a gamma-like tail or a regularly varying tail, and to failures at Poisson times. Different types of conditional limit occur, in particular exponentially tilted Gumbel distributions and Pareto distributions. The algorithms based upon importance distributions for T using...

dbEM: A database of epigenetic modifiers curated from cancerous and normal genomes

Science.gov (United States)

Singh Nanda, Jagpreet; Kumar, Rahul; Raghava, Gajendra P. S.

2016-01-01

We have developed a database called dbEM (database of Epigenetic Modifiers) to maintain the genomic information of about 167 epigenetic modifiers/proteins, which are considered as potential cancer targets. In dbEM, modifiers are classified on functional basis and comprise of 48 histone methyl transferases, 33 chromatin remodelers and 31 histone demethylases. dbEM maintains the genomic information like mutations, copy number variation and gene expression in thousands of tumor samples, cancer cell lines and healthy samples. This information is obtained from public resources viz. COSMIC, CCLE and 1000-genome project. Gene essentiality data retrieved from COLT database further highlights the importance of various epigenetic proteins for cancer survival. We have also reported the sequence profiles, tertiary structures and post-translational modifications of these epigenetic proteins in cancer. It also contains information of 54 drug molecules against different epigenetic proteins. A wide range of tools have been integrated in dbEM e.g. Search, BLAST, Alignment and Profile based prediction. In our analysis, we found that epigenetic proteins DNMT3A, HDAC2, KDM6A, and TET2 are highly mutated in variety of cancers. We are confident that dbEM will be very useful in cancer research particularly in the field of epigenetic proteins based cancer therapeutics. This database is available for public at URL: http://crdd.osdd.net/raghava/dbem.

Rapid Development of Microsatellite Markers with 454 Pyrosequencing in a Vulnerable Fish<em>,> the Mottled Skate<em>, Raja em>pulchra>

Full Text Available <em>Mytilus coruscusem> (family Mytilidae is one of the most important marine shellfish species in Korea. During the past few decades, this species has become endangered due to the loss of habitats and overfishing. Despite this species’ importance, information on its genetic background is scarce. In this study, we developed microsatellite markers for <em>M.> coruscusem> using next-generation sequencing. A total of 263,900 raw reads were obtained from a quarter-plate run on the 454 GS-FLX titanium platform, and 176,327 unique sequences were generated with an average length of 381 bp; 2569 (1.45% sequences contained a minimum of five di- to tetra-nucleotide repeat motifs. Of the 51 loci screened, 46 were amplified successfully, and 22 were polymorphic among 30 individuals, with seven of trinucleotide repeats and three of tetranucleotide repeats. All loci exhibited high genetic variability, with an average of 17.32 alleles per locus, and the mean observed and expected heterozygosities were 0.67 and 0.90, respectively. In addition, cross-amplification was tested for all 22 loci in another congener species, <em>M.> <em>galloprovincialis.> None of the primer pairs resulted in effective amplification, which might be due to their high mutation rates. Our work demonstrated the utility of next-generation 454 sequencing as a method for the rapid and cost-effective identification of microsatellites. The high degree of polymorphism exhibited by the 22 newly developed microsatellites will be useful in future conservation genetic studies of this species.

Sampling plan for the analysis of aflatoxin in peanuts and corn: an update Sistema de amostragem para análise de aflatoxinas em amendoim e milho: uma atualização

Directory of Open Access Journals (Sweden)

Homero Fonseca

2002-06-01

Full Text Available The aim of this paper was to update the sampling plan for analysis of mycotoxins in grains, formerly published by the author. The proposed alterations were based on the acquired experience on its application and on FAO recommendations. This update restricts the scope of the former plan and establishes a sampling plan for analysis of aflatoxin in peanuts and corn, by means of modified formulas, the minimum number of sacks or points (when in bulk from which incremental samples should be drawn to make a bulk sample. Fractional exponents (square roots of the formulas proportionally decrease the number of sacks/points to be sampled as the lot size increases. Operating Characteristic (OC curves developed for in-shell and shelled peanuts and corn as well as trend curves of the coefficient variation for different sample sizes (weights are presented.O objetivo deste trabalho foi atualizar a metodologia de amostragem para análise de micotoxinas em grãos, anteriormente publicada pelo autor. As alterações propostas tiveram por base a experiência adquirida na sua utilização e em recomendações da FAO. Esta atualização restringe a aplicação do método anterior e estabelece um plano de amostragem para análise de aflatoxina em amendoim e em milho por meio de fórmulas modificadas, o mínimo de sacos ou pontos (quando a granel dos quais devem ser retiradas amostras incrementais para constituir uma amostra. Expoentes fracionários (raiz quadrada das fórmulas diminuem proporcionalmente o número de sacos/pontos a serem amostrados, à medida que o lote aumenta de tamanho. Curvas de operação característica (OC desenvolvidas para amendoim em casca e descascado e milho, bem como curvas de tendência dos coeficientes de variação, para diferentes tamanhos de amostra (peso, são apresentadas.

Stress e esgotamento em professores: importância dos processos de avaliação cognitiva

OpenAIRE

Reis, Silvi Borges

2016-01-01

Dissertação de mestrado integrado em Psicologia Este estudo analisou a experiência de stress e esgotamento em professores e o papel da avaliação cognitiva na relação estabelecida entre stress e esgotamento. Participaram no estudo 551 professores, sendo 129 do sexo masculino e 317 do sexo feminino. As idades variaram entre 28 e 67 anos (M = 46.88; DP = 7.80). O protocolo de avaliação incluiu um questionário demográfico, a Escala de Avaliação Cognitiva, o Questionário de Stress em Professore...

Avaliação parasitológica em alfaces (Lactuca sativa L. comercializadas em Serra Talhada, Pernambuco, Brasil / Parasitological evaluation in lettuces (Lactuca sativa L. marketed in Serra Talhada, Pernambuco, Brazil

Directory of Open Access Journals (Sweden)

Rebeca Gonçalves de Oliveira

2014-08-01

Full Text Available A prevalência de parasitoses intestinais cresce de forma expansiva no Brasil e em muitos países. A ocorrência de enteroparasitoses advém de várias maneiras, inclusive por con-sumo de vegetais contaminados, representando um grande problema em nível mundial. O objetivo deste trabalho foi avaliar a contaminação por parasitas intestinais em horta-liças comercializadas em Serra Talhada-PE. As amostras das hortaliças foram coletadas nas unidades de produção (hortas, na unidade de recepção do Programa de Aquisição de Alimentos (PAA e em diversos estabelecimentos comerciais localizadas no município. As amostras foram colocadas em sacos plásticos e mantidas em caixa isotérmica; em seguida, foram encaminhadas ao laboratório de Biologia da Unidade Acadêmica de Serra Talhada-UFRPE. Para a identificação dos parasitas foi utilizado o método de sedimenta-ção espontânea. Observou-se que das 80 amostras de alface analisadas 97,5% estavam positivas para formas parasitárias e outros organismos microscópicos, incluindo ovos e larvas de nematoides, cistos de protozoários, ovos de cestódeos e alguns artrópodes (insetos e ácaros. É de suma importância o conhecimento dos produtores e manipu-ladores em geral a respeito da contaminação, bem como o conhecimento das técnicas sanitizantes desenvolvidas para hortaliças, com intuito de diminuir a contaminação em todas as etapas ocorrentes desde o cultivo até ao consumo. ------------------------------------------------------------------------------------- Prevalence of intestinal parasites growing in Brazil and in many countries so expansive. The intestinal parasites comes in several ways, including by consumption of contami-nated vegetables, which represents a significant worldwide problem. The objective of this study is to assess the contamination by intestinal parasites in vegetables commer-cialized in Serra Talhada, in Pernambuco state. Samples of vegetables were collected at the

Métodos de amostragem de solos em áreas sob plantio direto no Sudoeste Goiano Methods of soil sampling in areas under no-tillage in the Southwest Goiás

Directory of Open Access Journals (Sweden)

Nelson H. D. Acqua

2013-02-01

Full Text Available A amostragem de solo é a etapa mais importante do programa de avaliação da sua fertilidade; ressalta-se que a recomendação de corretivos e de fertilizantes é definida a partir da interpretação dos resultados de análises químicas realizadas na amostra. Com o objetivo de avaliar esses resultados em função do método de amostragem amostras de solo foram retiradas em 12 áreas distintas cultivadas há 2, 5 e 10 anos sob o sistema plantio direto. Utilizaram-se o trado holandês e a furadeira elétrica retirando-se as amostras de solo em 3 posições e 2 profundidades e se avaliando a fertilidade do solo em função do tempo de adoção do sistema plantio direto. Constatou-se incremento do teor de P nas áreas cultivadas há 10 anos sob plantio direto, em relação às demais. Os valores de Ca, Mg, P, K, pH, CTC e V apresentaram gradiente de concentração em função do não revolvimento do solo, aplicações superficiais de calcário e adubações na linha de plantio. Os equipamentos de amostragem influíram nos resultados das análises de solo sendo que todos os macronutrientes, com exceção do S, e todos os micronutrientes, apresentaram valores elevados quando amostrados com a furadeira elétrica.Soil sampling is the first and fundamental step in an evaluation program of soil fertility, and the recommendation of lime and fertilizer is defined through the interpretation of the results of chemical analysis of the sample. With the objective of evaluating the results of the chemical analysis of the soil as a function of the sampling method, soil samples were collected from 12 different areas that have been under no-tillage system for 2, 5 and 10 years. The Ducth auger hole and the electric drill were used to collect the soil samples at 3 different positions and 2 depths, evaluating the soil fertility as a function of time of the direct planing system. There was an increment of P in areas with 10 years under no-tillage system in comparison

Importance sampling and histogrammic representations of reactivity functions and product distributions in Monte Carlo quasiclassical trajectory calculations

International Nuclear Information System (INIS)

Faist, M.B.; Muckerman, J.T.; Schubert, F.E.

1978-01-01

The application of importance sampling as a variance reduction technique in Monte Carlo quasiclassical trajectory calculations is discussed. Two measures are proposed which quantify the quality of the importance sampling used, and indicate whether further improvements may be obtained by some other choice of importance sampling function. A general procedure for constructing standardized histogrammic representations of differential functions which integrate to the appropriate integral value obtained from a trajectory calculation is presented. Two criteria for ''optimum'' binning of these histogrammic representations of differential functions are suggested. These are (1) that each bin makes an equal contribution to the integral value, and (2) each bin has the same relative error. Numerical examples illustrating these sampling and binning concepts are provided

Importance of sampling frequency when collecting diatoms

KAUST Repository

Wu, Naicheng

2016-11-14

There has been increasing interest in diatom-based bio-assessment but we still lack a comprehensive understanding of how to capture diatoms’ temporal dynamics with an appropriate sampling frequency (ASF). To cover this research gap, we collected and analyzed daily riverine diatom samples over a 1-year period (25 April 2013–30 April 2014) at the outlet of a German lowland river. The samples were classified into five clusters (1–5) by a Kohonen Self-Organizing Map (SOM) method based on similarity between species compositions over time. ASFs were determined to be 25 days at Cluster 2 (June-July 2013) and 13 days at Cluster 5 (February-April 2014), whereas no specific ASFs were found at Cluster 1 (April-May 2013), 3 (August-November 2013) (>30 days) and Cluster 4 (December 2013 - January 2014) (<1 day). ASFs showed dramatic seasonality and were negatively related to hydrological wetness conditions, suggesting that sampling interval should be reduced with increasing catchment wetness. A key implication of our findings for freshwater management is that long-term bio-monitoring protocols should be developed with the knowledge of tracking algal temporal dynamics with an appropriate sampling frequency.

Grid-trapping of the wood mouse (<em>Apodemus sylvaticusem> in a mediterranean oak-wood (Sicily / Analisi del popolamento di topo selvatico (<em>Apodemus sylvaticusem> in un querceto mediterraneo (Sicilia

Directory of Open Access Journals (Sweden)

Maurizio Sarà

1993-06-01

Full Text Available Abstract A grid-trapping (CMR Method of the Wood Mouse (<em>A. sylvaticusem> resident population was carried on three sample areas in a Mediterranean Oak-wood (Bosco della Ficuzza, Palermo. Fifty live traps were settled on a 0.5 ha grid at each sample area and permitted to calculate the Petersen-Lincoln Index (modified by Chapman. The relative density in the typical oak-wooded area (20.4/ha is highest than in the ecotonal and gazed sample area (12.6/ha. Analysis of ground permanence shows that the population in the wooded area is more dinamic than in the other area; in the former area a large number of new captures occurs, in fact, each month and the monthly variation of the relative density has a different trend. These results would confirm the indirect data coming from pellets analysis showing how in Sicily the highest densities occur in woodlands (oak-woods, as well as beech forests. The ecological niche of the Wood Mouse, due also to the apparent lack of <em>A. flavicollisem>, is thus larger than in peninsular Italy and continental Europe. The reproductive season lasts over the whole year but the birth peaks occurred in summer (1988 and late fall (1989. Population each year stabilizes for overwintering and later (Jun-Nov is almost completely renowed. Moreover, differences in sex and age trappability in relation to the two mode1 of traps utilized and a low mortality due to the cautions in handling the trapped mice, were recorded. Riassunto Allo scopo di evidenziare le differenze tra i popolamenti di <em>Apodemus sylvaticusem> (Linnaeus, 1758 in relazione all'habitat, sono state effettuate in una tipica querceta mediterranea (Bosco della Ficuzza, PA griglie di trappolamento in tre aree campione, ciascuna con differenti caratteristiche ambientali e morfologiche. Il campionamento, che si è protratto per circa due anni, è stato condotto con il metodo CMR (cattura-marcaggio-ricattura. I risultati ottenuti

Comparison of semi-automatized assays for anti-T. gondii IgG detection in low-reactivity serum samples: importance of the results in patient counseling Comparação de ensaios semi-automatizados para pesquisa de IgG anti-T. gondii em amostras de soros de baixa reatividade: importância dos resultados no aconselhamento do paciente

Directory of Open Access Journals (Sweden)

Paulo Guilherme Leser

2003-06-01

Full Text Available Toxoplasmosis is a disease which can cause severe congenital infection and is normally diagnosed by the detection of T. gondii specific antibodies in the serum of infected patients. Several different tests allow to distinguish recent from past infections and to quantify anti-T. gondii specific IgG, and the results can be used as markers for immunity. In the present study, we compare the performance of two different methodologies, the Elfa (bioMérieux S.A and the Meia (Abbott Laboratories in detecting T. gondii specific IgG in low-reactivity sera. Of 76 analyzed samples, three presented discrepant results, being positive in the Abbott AxSYM Toxo IgG assay, and negative in the bioMérieux Vidas Toxo IgG II assay. By using other tests, the three sera were confirmed to be negative. The results are discussed in the context of their importance for patient management, especially during pregnancy.Toxoplasmose, doença conhecida por sua severidade na infecção congênita é geralmente diagnosticada pela demonstração de anticorpos específicos contra antígenos de T. gondii, presentes no soro de indivíduos infectados. Diferentes testes são disponíveis para diferenciar infecção recente de infecção pregressa, para quantificar anticorpos IgG anti-T. gondii nos soros dos pacientes e utilizar os resultados como marcadores de imunidade. Neste trabalho apresentamos os resultados do estudo comparativo de duas tecnologias, Elfa (bioMérieux S.A. e Meia (Abbott Laboratories, para pesquisa de anticorpos IgG anti-T. gondii em amostras de soros de baixa reatividade. De 76 amostras processadas, três apresentaram resultados discrepantes, reagentes para AxSYM Toxo IgG e não-reagentes para Vidas Toxo IgG II. A confirmação dos resultados, feita por bateria de testes, mostrou que todas as três amostras eram não-reagentes. Os resultados são discutidos em sua importância e orientação clínica, principalmente para a paciente gestante.

40 CFR 80.330 - What are the sampling and testing requirements for refiners and importers?

Science.gov (United States)

2010-07-01

... and importers shall collect a representative sample from each batch of gasoline produced or imported... January 1, 2004, any refiner who produces gasoline using computer-controlled in-line blending equipment is... listed in § 80.46(a)(3) to measure the sulfur content of gasoline they produce or import. (2) Except as...

Epidemiology of Human Parechovirus Type1 in Clinical Samples from Children with Gastroenteritis Using RT-PCR

Directory of Open Access Journals (Sweden)

F Ghazi

2012-05-01

Full Text Available

<em>Background and Objectives:em> Human parechovirus type-1 (HPeV-1 is a genus of picornaviridea with a single stranded positive sense RNA genome. In general it seems to be responsible for more gastrointestinal and respiratory syndromes and less responsible for central nervous system (CNS symptoms. Since there is no accurate information about diagnosis and epidemiology of HPeV-1 in Iran and it is very important to distinguish between viral and bacterial diarrhea to decrease the unnecessary use of antibiotics, this study aimed at rapid detection and epidemiology of HPeV-1 in stool samples from children with gastroenteritis using specific RT-PCR.

<em>Methods:> Viral RNA was isolated from 472 stool samples from children (under 4 years old with diarrhea; CDNA was prepared and amplified using specific primers from 5^′untranslated region (5^′ UTR of HPeV-1 genome by nested RT-PCR. Amplified DNA product was electrophoresed on 1% agarose gel and a single band of 265 bp was obtained. Data were analyzed by SPSS software. We also performed a comparison between the cell culture (Vero and RT-PCR method for HPeV1 detection.

<em>Results:> Out of 472 samples examined during two years, 112 samples were HpeV-1 positive (23.7%. The results showed that the prevalence of this virus was in children under one year (6-12 months old with diarrhea (p=0.036 in spring and autumn (p<0.001. Boys had more positive cases than the girls (p<0.001. Out of 20 samples which were found positive by HPeV1 RT-PCR only three of them showed CPE on Vero Cells after a week.

<em>Conclusion:> The results revealed that RT-PCR is a more practical and sensitive technique for HPeV-1 detection directly from clinical samples, which is valuable for epidemiology. Also, the rapid

Fumigant Antifungal Activity of Myrtaceae Essential Oils and Constituents from <em>Leptospermum petersoniiem> against Three <em>Aspergillus> Species

Directory of Open Access Journals (Sweden)

Il-Kwon Park

2012-09-01

Full Text Available Commercial plant essential oils obtained from 11 Myrtaceae plant species were tested for their fumigant antifungal activity against <em>Aspergillus ochraceusem>, <em>A. flavusem>, and <em>A. nigerem>. Essential oils extracted from<em> em>Leptospermum> <em>petersonii> at air concentrations of 56 × 10⁻³ mg/mL and 28 × 10⁻³ mg/mL completely inhibited the growth of the three <em>Aspergillus> species. However, at an air concentration of 14 × 10⁻³ mg/mL, inhibition rates of <em>L. petersoniiem> essential oils were reduced to 20.2% and 18.8% in the case of <em>A. flavusem> and <em>A. nigerem>, respectively. The other Myrtaceae essential oils (56 × 10⁻³ mg/mL only weakly inhibited the fungi or had no detectable affect. Gas chromatography-mass spectrometry analysis identified 16 compounds in <em>L. petersoniiem>> em>essential> em>oil.> em>The antifungal activity of the identified compounds was tested individually by using standard or synthesized compounds. Of these, neral and geranial inhibited growth by 100%, at an air concentration of 56 × 10⁻³ mg/mL, whereas the activity of citronellol was somewhat lover (80%. The other compounds exhibited only moderate or weak antifungal activity. The antifungal activities of blends of constituents identified in <em>L. petersoniiem> oil indicated that neral and geranial were the major contributors to the fumigant and antifungal activities.