WorldWideScience

Sample records for bootstrap aplicados em

  1. Seletividade do halosulfuron-methyl aplicado em pré-emergência da cultura da mamoneira

    Directory of Open Access Journals (Sweden)

    Renata L. M. da Silva

    2015-07-01

    Full Text Available A mamoneira é bastante sensível à competição, havendo necessidade de ampliar as alternativas de manejo de plantas daninhas, considerando-se principalmente as opções de herbicidas seletivos, visando favorecer a expansão das áreas de cultivo. O objetivo deste trabalho foi avaliar a seletividade do herbicida halosulfuron-methyl para a cultura da mamoneira aplicado em pré-emergência, antes da semeadura. Dois experimentos foram conduzidos em condições de casa-de-vegetação, um com solo arenoso e outro com franco-argilo-arenoso, em delineamento inteiramente casualizado com quatro repetições. Os tratamentos se constituíram de cinco períodos entre a aplicação do herbicida e a semeadura (0, 7, 14, 21 e 28 dias e uma testemunha sem aplicação. As avaliações realizadas foram: altura de plantas aos 7, 14, 21 e 28 dias após a emergência (DAE; diâmetro do caule, área foliar, volume de raízes, massa seca de parte aérea e raízes aos 28 DAE. Halosulfuron-methyl (112,5 g ha-1 é seletivo para a cultura da mamoneira quando aplicado na modalidade de pré-emergência, antes da semeadura.

  2. Seletividade de herbicidas aplicados em pré-emergência, isolados e em misturas, na cultura do algodão.

    OpenAIRE

    INOUE, Miriam Hiroko; Jardini, Débora Curado; Oliveira Junior, Rubem Silvério de; Mendes, Kassio Ferreira; Ben, Ronei; Possamai, Ana Cássia Silva

    2012-01-01

    A cultura do algodão tem grande importância econômica e ocial, visto que é a fibra mais utilizada no setor têxtil. Contudo, apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto objetivouse com este trabalho avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a variedade FM...

  3. Recomendações sobre design informacional aplicado em motion graphics

    Directory of Open Access Journals (Sweden)

    André Luiz Fronza

    2014-01-01

    Full Text Available Tendo sua origem no cinema, o motion graphics tornou-se uma linguagem audiovisual bastante difundida a partir dos anos 1990 devido ao avanço tecnológico na área da computação gráfica. É caracterizado por concentrar-se em uma área de criação que permite a combinação e manipulação de ilustrações, elementos gráficos, fotografia e vídeos, num determinado espaço-tempo unido ao uso de música e efeitos sonoros. Neste contexto, o presente artigo relata a pesquisa que objetivou identificar se, para o público jovem, o motion graphicstransmite informações com maior efetividade do que um material estático. Também buscou-se compreender o processo de criação e concepção do motion graphics, tendo o intuito de futuramente formular um guia para os profissionais da área a fim de auxiliá-los no processo de organização visual e cognitiva da mensagem em projetos desse tipo. Para alcance dos objetivos propostos, foi realizada uma pesquisa d e caráter misto, do tipo exploratória, utilizando dados quantitativos obtidos a partir de um questionário fechado aplicado a alunos de Ensino Médio e informações qualitativas provindas de dois focus group com estudantes de Design. Constatou-se que há diferenças na percepção de informações estáticas em comparação às animadas (motion graphics e que o motion designer, ao projetar uma animação,deve ter primor na aplicação dos princípios básicos que concernem o design da informação.

  4. Bootstrap, Wild Bootstrap and Generalized Bootstrap

    OpenAIRE

    Mammen, Enno

    1995-01-01

    Some modifications and generalizations of the bootstrap procedurehave been proposed. In this note we will consider the wild bootstrap and the generalized bootstrap and we will give two arguments why it makes sense touse these modifications instead of the original bootstrap. The firstargument is that there exist examples where generalized and wild bootstrapwork, but where the original bootstrap fails and breaks down. The secondargument will be based on higher order considerations. We will show...

  5. Seletividade de herbicidas aplicados em pré-emergência na cultura do algodão Selectivity of herbicides applied to pre-emergent cotton crops

    OpenAIRE

    Miriam Hiroko Inoue; Rubém Silvério de Oliveira Junior; Ronei Ben; Rivanildo Dallacort; Cassiano Luiz Sztoltz

    2013-01-01

    A cultura do algodão tem grande importância econômica e social, visto que é a fibra mais utilizada no setor têxtil. Contudo é uma cultura que apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto o trabalho objetivou avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a var...

  6. Modelos aplicados às atividades de educação em saúde Modelos aplicados a las actividades de educación en salud Models applied to the activities of health education

    OpenAIRE

    Maria Fernanda Santos Figueiredo; João Felício Rodrigues-Neto; Maísa Tavares Souza Leite

    2010-01-01

    Este estudo objetivou compreender quais os modelos educacionais têm sido aplicados às atividades de educação em saúde. Trata-se de uma revisão de literatura, sobre o tema “Modelos de Educação” e “Educação em Saúde”, utilizando como referenciais livros-textos contemporâneos de especialistas da área de educação e periódicos sobre tais temas, disponíveis nas principais bases de dados. Os resultados revelaram que o Modelo Tradicional de educação em saúde objetiva transmissão do conhecimento e exp...

  7. Análise comparativa de classificadores digitais em imagens do Landsat-8 aplicados ao mapeamento temático

    Directory of Open Access Journals (Sweden)

    Danilo Francisco Trovo Garofalo

    2015-07-01

    Full Text Available Resumo: O objetivo deste trabalho foi avaliar o desempenho dos classificadores digitais SVM e K-NN para a classificação orientada a objeto em imagens Landsat-8, aplicados ao mapeamento de uso e cobertura do solo da Alta Bacia do Rio Piracicaba-Jaguari, MG. A etapa de pré-processamento contou com a conversão radiométrica e a minimização dos efeitos atmosféricos. Em seguida, foi feita a fusão das bandas multiespectrais (30 m com a banda pancromática (15 m. Com base em composições RGB e inspeções de campo, definiram-se 15 classes de uso e cobertura do solo. Para a segmentação de bordas, aplicaram-se os limiares 10 e 60 para as configurações de segmentação e união no aplicativo ENVI. A classificação foi feita usando SVM e K-NN. Ambos os classificadores apresentaram elevados valores de índice Kappa (k: 0,92 para SVM e 0,86 para K-NN, significativamente diferentes entre si a 95% de probabilidade. Uma significativa melhoria foi observada para SVM, na classificação correta de diferentes tipologias florestais. A classificação orientada a objetos é amplamente aplicada em imagens de alta resolução espacial; no entanto, os resultados obtidos no presente trabalho mostram a robustez do método também para imagens de média resolução espacial.

  8. REGULADOR DE CRESCIMENTO E Trichoderma harzianum APLICADOS EM SEMENTES DE FEIJOEIRO CULTIVADO EM SUCESSÃO A CULTURAS DE COBERTURA GROWTH REGULATOR AND Trichoderma harzianum APPLIED TO COMMON BEAN SEEDS CULTIVATED IN SUCCESSION TO COVER CROPS

    OpenAIRE

    Marcos Antônio Machado Mesquita; Tatiely Gomes Bernardes; Pedro Marques da Silveira

    2010-01-01

    Avaliou-se o efeito de regulador de crescimento e <em>Trichoderma harzianumem>,> em>aplicados em sementes de feijoeiro irrigado, em sucessão a diferentes culturas de cobertura....

  9. Efeito de herbicidas aplicados em solo de várzea sobre a cultura do girassol Effect of herbicides applied on sunflower crop in wetland soil

    OpenAIRE

    E.A.L Erasmo; N.V. Costa; A.S Peruzzo; J.E Barberato Junior

    2010-01-01

    Objetivou-se neste trabalho avaliar em solos de várzea o efeito de herbicidas préemergentes, aplicados isoladamente e em mistura, sobre a cultura do girassol. A variedade de girassol Embrapa V122 e o híbrido triplo Agrobel 972 foram avaliados individualmente, utilizando-se o delineamento experimental de blocos casualizados, com quatro repetições. Foram realizados dois experimentos, e os tratamentos utilizados em ambos foram: oxadiazon (250 g ha-1), oxyfluorfen (240 g ha-1), S-metolachlor (1.4...

  10. Seletividade de herbicidas aplicados em pré-emergência, isolados e em misturas, na cultura do algodão = Selective of applied herbicides in pre-emergency, isolated and in mixtures, in the culture of the cotton.

    OpenAIRE

    Miriam Hiroko Inoue; Débora Curado Jardini; Rubem Silvério de Oliveira Junior , Ronei Ben , Ana; Kassio Ferreira Mendes; Ronei Ben; Cássia Silva Possamai

    2012-01-01

    A cultura do algodão tem grande importância econômica e social, visto que é a fibra mais utilizada no setor têxtil. Contudo, apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto objetivouse com este trabalho avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a variedade F...

  11. Inseminação artificial ovina com semen refrigerado aplicado em diferentes vias

    OpenAIRE

    Milczewski, Viviane

    2012-01-01

    Resumo: O presente trabalho objetivou inicialmente comparar a eficiência in vitro de 6 diluentes na conservação de sêmen ovino à temperatura de 5°C por 8 horas. Em uma segunda etapa 140 ovelhas foram inseminadas para avaliação de 2 dos diluentes que demonstraram maior eficiência in vitro, pelas vias cervical superficial e intra-uterina, em diferentes momentos de aplicação após a sincronização do estro. Foram constituídos 23 homogeneizados de sêmen, divididos em 6 alíquotas, nos quais foram ac...

  12. Extending Bootstrap

    CERN Document Server

    Niska, Christoffer

    2014-01-01

    Practical and instruction-based, this concise book will take you from understanding what Bootstrap is, to creating your own Bootstrap theme in no time! If you are an intermediate front-end developer or designer who wants to learn the secrets of Bootstrap, this book is perfect for you.

  13. CONCRETE-RUBBER TYRES USED IN BIKE PATH = CONCRETO COM BORRACHA DE PNEUS APLICADO EM CICLOVIA

    Directory of Open Access Journals (Sweden)

    José Franklin Moreira

    2014-10-01

    ço podem se constituir em matéria-prima para outras utilizações. Dessa forma, a destinação final e reutilização ambientalmente corretas, adequadas e seguras são desafios a serem vencidos em todos os segmentos. A construção civil impacta o meio ambiente, mas pode se constituir em sorvedouro de resíduos com a devida comprovação técnica. Para a utilização de resíduos na construção civil encontram-se barreiras, tanto tecnológicas como políticas, tornando incipiente ainda essa prática. Este trabalho é um relato de uma experiência conjunta entre prefeitura municipal, empresa de construção civil e instituição de ensino, para a aplicação de borracha originada do picotamento de pneus automotivos em uma ciclovia. Utilizou-se um concreto com adição de borracha de pneu, em substituição ao agregado miúdo, para a execução de uma ciclovia e verificou-se ser possível sua aplicação em substituição ao concreto convencional. Este equipamento urbano oferece opção de locomoção, fomenta hábitos de vida mais saudáveis e lazer para a população atendida, e pode contribuir para a sustentabilidade.

  14. Seletividade de herbicidas, aplicados em pós-emergência, às plantas de alfafa Selectivity of applied port-emergence herbicides in the alfafa plants

    OpenAIRE

    Gláucia de Mello; Ricardo A. Reis; Julio C. Durigan; Lino R. Ferreira

    2000-01-01

    Foram conduzidos doi experimentos na UNESP/Jaboticabal, em casa-de-vegetação, com o objetivo de avaliar-se a toxicidade de diferentes herbicidas, aplicados em pós-emergênica, às plantas de alfafa. No primeiro, utilizou-se de um delineamento experimental com parcelas inteiramente casualizadas para avaliar-se os efeitos fitotóxicos dos seguintes herbicidas: MSMA, clethodim + óleo mineral, lactofen, fluazifop-pbutil, fomesafen + óleo mineral haloxyfop-methyl + óleo mineral, fenoxaprop-ethyl, chl...

  15. Recomendações sobre design informacional aplicado em motion graphics

    OpenAIRE

    André Luiz Fronza; Arina Blum; Mary Vonni Meürer

    2014-01-01

    Tendo sua origem no cinema, o motion graphics tornou-se uma linguagem audiovisual bastante difundida a partir dos anos 1990 devido ao avanço tecnológico na área da computação gráfica. É caracterizado por concentrar-se em uma área de criação que permite a combinação e manipulação de ilustrações, elementos gráficos, fotografia e vídeos, num determinado espaço-tempo unido ao uso de música e efeitos sonoros. Neste contexto, o presente artigo relata a pesquisa que objetivou identificar se, para o ...

  16. Bootstrapping heteroskedastic regression models: wild bootstrap vs. pairs bootstrap

    OpenAIRE

    Flachaire, Emmanuel

    2005-01-01

    International audience In regression models, appropriate bootstrap methods for inference robust to heteroskedasticity of unknown form are the wild bootstrap and the pairs bootstrap. The finite sample performance of a heteroskedastic-robust test is investigated with Monte Carlo experiments. The simulation results suggest that one specific version of the wild bootstrap outperforms the other versions of the wild bootstrap and of the pairs bootstrap. It is the only one for which the bootstrap ...

  17. Efeito de herbicidas aplicados em solo de várzea sobre a cultura do girassol Effect of herbicides applied on sunflower crop in wetland soil

    Directory of Open Access Journals (Sweden)

    E.A.L Erasmo

    2010-12-01

    Full Text Available Objetivou-se neste trabalho avaliar em solos de várzea o efeito de herbicidas préemergentes, aplicados isoladamente e em mistura, sobre a cultura do girassol. A variedade de girassol Embrapa V122 e o híbrido triplo Agrobel 972 foram avaliados individualmente, utilizando-se o delineamento experimental de blocos casualizados, com quatro repetições. Foram realizados dois experimentos, e os tratamentos utilizados em ambos foram: oxadiazon (250 g ha-1, oxyfluorfen (240 g ha-1, S-metolachlor (1.440 g ha-1, flumetsulam (120 g ha-1, pendimethalin (1.000 g ha-1, oxyfluorfen+S-metolachlor (192+960 g ha-1, flumetsulam +S-metolachlor (72+960 g ha-1, pendimethalin+S-metolachlor (1.000 + 1.440 g ha-1, pendimethalin+flumetsulam (1.000+72 g ha-1, além de duas testemunhas, sem e com capina. Os dados de altura de planta, diâmetro do caule, diâmetro do capítulo e da produção de grãos foram submetidos aos testes estatísticos multivariados de análise de agrupamento e análise de componentes principais. Os resultados foram semelhantes em ambos os cultivares, com a formação de três grupos principais, sendo o primeiro e o segundo constituídos pelas testemunhas sem e com capina, respectivamente. O terceiro grupo foi constituído pelos herbicidas aplicados isoladamente e em mistura. Dessa forma, verificou-se que os efeitos causados pelos herbicidas aplicados isoladamente e em mistura sobre as variáveis analisadas foram menos prejudiciais em relação aos da interferência das plantas daninhas. Esses resultados evidenciaram potencial de seletividade dos herbicidas aplicados isoladamente e em mistura na variedade de girassol Embrapa V122 e no híbrido triplo Agrobel 972, nas condições em que foram avaliados.This study aimed to evaluate the effect of applying different pre-emergent herbicides, alone and in combination, on sunflower crop in wetland soil. The sunflower variety Embrapa V122 and the triple hybrid Agrobel 972 were evaluated individually

  18. Survey bootstrap and bootstrap weights

    OpenAIRE

    Stas Kolenikov

    2008-01-01

    In this presentation, I will review the bootstrap for complex surveys with designs featuring stratification, clustering, and unequal probability weights. I will present the Stata module bsweights, which creates the bootstrap weights for designs specified through and supported by svy. I will also provide simple demonstrations highlighting the use of the procedure and its syntax. I will discuss various tuning parameters and their impact on the performance of the procedure, and I will give argum...

  19. Wild Bootstrap Versus Moment-Oriented Bootstrap

    OpenAIRE

    Sommerfeld, Volker

    1997-01-01

    We investigate the relative merits of a “moment-oriented” bootstrap method of Bunke (1997) in comparison with the classical wild bootstrap of Wu (1986) in nonparametric heteroscedastic regression situations. The “moment-oriented” bootstrap is a wild bootstrap based on local estimators of higher order error moments that are smoothed by kernel smoothers. In this paper we perform an asymptotic comparison of these two dierent bootstrap procedures. We show that the moment-oriented bootstrap is in ...

  20. Bootstrap unloader

    Science.gov (United States)

    Pfiffner, H. J.

    1969-01-01

    Circuit can sample a number of transducers in sequence without drawing from them. This bootstrap unloader uses a differential amplifier with one input connected to a circuit which is the equivalent of the circuit to be unloaded, and the other input delivering the proper unloading currents.

  1. Bootstrap essentials

    CERN Document Server

    Bhaumik, Snig

    2015-01-01

    If you are a web developer who designs and develops websites and pages using HTML, CSS, and JavaScript, but have very little familiarity with Bootstrap, this is the book for you. Previous experience with HTML, CSS, and JavaScript will be helpful, while knowledge of jQuery would be an extra advantage.

  2. Uma Comparação entre Técnicas de Propagação de Erros em Astrofísica: Monte Carlo x Bootstrap

    Science.gov (United States)

    Zabot, Alexandre; Baptista, Raymundo

    2005-07-01

    Neste trabalho é feito um estudo comparativo entre dois algoritmos numéricos usados para propagação de erros em dados experimentais. Um deles é conhecido por Método de Monte carlo e o outro por Método de Bootstrap. Recentemente, Dhullon & Watson argüiram que a aplicação do método de Monte Carlo introduz ruído nos dados, e propuseram então a utilização do Bootstrap como alternativa capaz de produzir resultados superiores. O objetivo deste trabalho é testar a validade dessa afirmação. As duas técnicas foram aplicadas a três problemas diferentes: o ajsute de modelos de emissão LTE simples e atmosfera estelar a espectros estelares observados e o ajuste de curvas de luz de eclipses de Variáveis Cataclísmicas para a detemrinação da distribuição radial de brilho dos seus discos de acréscimo. Os métodos foram testados quanto à sua robusteza, ou seja, a capacidade de prover resultados coerentes enre si. Além disso, as soluções dos métodos foram comparadas. Os resultados indicam que não existe evidência de superioridade de um métodos em relação ao outro.

  3. Seven Stages of Bootstrap

    OpenAIRE

    Beran, Rudolf

    1994-01-01

    This essay is organized around the theoretical and computationalproblem of constructing bootstrap confidence sets, with forays into relatedtopics. The seven section headings are: Introduction; The Bootstrap World;Bootstrap Confidence Sets; Computing Bootstrap Confidence Sets; Quality ofBootstrap Confidence Sets; Iterated and Two-step Boostrap; Further Resources.

  4. REGULADOR DE CRESCIMENTO E Trichoderma harzianum APLICADOS EM SEMENTES DE FEIJOEIRO CULTIVADO EM SUCESSÃO A CULTURAS DE COBERTURA GROWTH REGULATOR AND Trichoderma harzianum APPLIED TO COMMON BEAN SEEDS CULTIVATED IN SUCCESSION TO COVER CROPS

    Directory of Open Access Journals (Sweden)

    Marcos Antônio Machado Mesquita

    2010-10-01

    Full Text Available

    Avaliou-se o efeito de regulador de crescimento e <em>Trichoderma harzianumem>,> em>aplicados em sementes de feijoeiro irrigado, em sucessão a diferentes culturas de cobertura. O delineamento experimental consistiu de parcelas subdivididas, em blocos casualizados, com quatro repetições. Nas parcelas, foram utilizadas culturas de cobertura, como as leguminosas guandu, estilosantes e crotalária, e as gramíneas milheto, capim mombaça, braquiária e braquiária consorciada com milho e sorgo. Nas subparcelas, os tratamentos foram: testemunha; 500 mL de regulador de crescimento, em 100 kg de sementes; 1.250 mL de fungicida biológico, em 100 kg de sementes; e 500 mL de regulador de crescimento mais 1.250 mL de fungicida biológico, em 100 kg de sementes. Aos 84 dias após o corte das culturas de cobertura, foi semeado o feijoeiro, cultivar BRS Valente. Foram avaliados a severidade de podridão radicular causada por <em>Rhizoctonia solaniem> e <em>Fusarium solani em>f.> em>sp.> phaseoliem>, incidência por murcha-de-fusário, estande, rendimento de grãos, massa de 100 grãos, número de vagens por planta e número de grãos por vagem do feijoeiro. Os tratamentos com fungicida biológico e regulador de crescimento não apresentaram efeito significativo, em relação às variáveis analisadas. A palhada de sorgo favoreceu o aumento das podridões radiculares e da murcha-de-fusário no feijoeiro.

    PALAVRAS-CHAVE: Horm

  5. Herbicidas inibidores da ALS aplicados em pós-emergência no arroz de terras altas ALS-inhibiting herbicides applied in upland-rice post-emergence

    OpenAIRE

    Petter, F.A.; L.P. Pacheco; A.M. Zuffo; F Alcântara Neto; W.R.M. Ribeiro

    2012-01-01

    Este trabalho teve por objetivo avaliar a seletividade de herbicidas inibidores da ALS recomendados para arroz irrigado, quando aplicados em diferentes estádios de desenvolvimento do arroz de terras altas. O experimento foi conduzido em campo, no município de Nova Xavantina-MT, no período de novembro de 2009 a abril de 2010. O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 5 x 3, composto pelos tratamentos herbicidas penoxsulam (36 g ha-1), bispyribac-Na (50 g ha-1), ...

  6. A Phylogeny of the Monocots, as Inferred from<em> rbcLem> and<em> atpAem> Sequence Variation, and a Comparison of Methods for Calculating Jackknife and Bootstrap Values

    DEFF Research Database (Denmark)

    Davis, Jerrold I.; Stevenson, Dennis W.; Petersen, Gitte;

    2004-01-01

    elements of Xyridaceae. A comparison was conducted of jackknife and bootstrap values, as computed using strict-consensus (SC) and frequency-within-replicates (FWR) approaches. Jackknife values tend to be higher than bootstrap values, and for each of these methods support values obtained with the FWR...

  7. Seletividade de herbicidas aplicados em pré-emergência na cultura do algodão Selectivity of herbicides applied to pre-emergent cotton crops

    Directory of Open Access Journals (Sweden)

    Miriam Hiroko Inoue

    2013-03-01

    Full Text Available A cultura do algodão tem grande importância econômica e social, visto que é a fibra mais utilizada no setor têxtil. Contudo é uma cultura que apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto o trabalho objetivou avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a variedade FMT-701, nas localidades de Diamantino-MT e Campos de Júlio-MT. O delineamento experimental utilizado foi em blocos casualizados com 16 tratamentos e 4 repetições. Para avaliar a seletividade foram realizadas avaliações de altura aos 36; 66 e 150 dias após a aplicação (DAA, fitointoxicação aos 14; 21; 29 e 36 DAA, estande aos 21 e 49 DAA, número de maçãs aos 141 DAA e produtividade do algodão em caroço aos 193 DAA. Os dados foram submetidos à análise conjunta e ao teste de agrupamento Scott-Knott (p>0,05. Os resultados indicaram que alguns tratamentos proporcionaram menor altura de plantas em determinadas avaliações e grande parte dos tratamentos causou injúrias na fase inicial da cultura. Verificou-se que os tratamentos não proporcionaram diferença significativa para as características de estande de plantas, número de maçãs e produtividade de algodão em caroço, comprovando que todos os tratamentos avaliados podem ser utilizados no manejo de plantas daninhas.The cultivation of cotton has great economic and social importance as it is the most widely used fibre in the textile sector. It is however a crop that is highly sensitive tweeds, and there are few selective herbicides for the crop. With this in mind, this study aimed to evaluate the selectivity of herbicides applied to pre-emergent cotton crops. The herbicides, alachlor, S-metolachlor, diuron, prometryne, trifluralin and oxyfluorfen were applied both

  8. Método do limiar de variabilidade da frequência cardíaca aplicado em pré-adolescentes obesos e não obesos

    Directory of Open Access Journals (Sweden)

    Mário Augusto Paschoal

    2011-06-01

    Full Text Available FUNDAMENTO: A detecção do limiar anaeróbico (LA pela análise da variabilidade da frequência cardíaca (LiVFC pode significar uma nova maneira de avaliação da capacidade funcional cardiorrespiratória (CFCR em pré-adolescentes. OBJETIVO: Testar o método de LiVFC para detecção do LA em pré-adolescentes não obesos (NO, obesos (O e obesos mórbidas (OM, a fim de determinar diferenças em sua CFCR. MÉTODOS: Foram estudados 30 pré-adolescentes, com idades entre 9 e 11 anos, divididos em três grupos de 10: a grupo NO - índice de massa corpórea (IMC com percentil do National Center for Chronic Disease Prevention and Health Promotion entre 5 e 85; b grupo O - IMC de percentil entre 95 e 97 e c grupo OM - IMC com percentil acima de 97. Todos foram submetidos a um protocolo incremental realizado em esteira rolante e registraram-se os batimentos cardíacos para detecção do LiVFC, que foi determinado pelo valor de 3,0 ms do índice do desvio-padrão 1 (SD1, extraído dos intervalos RR. RESULTADOS: Os valores médios no momento do LiVFC mostraram maiores valores para o grupo NO, destacando-se: a VO2 (ml/kg/min NO = 27,4 ± 9,2; O = 13,1 ± 7,6 e OM = 11,0 ± 1,7; b FC (bpm: NO = 156,3 ± 18,0; O =141,7 ± 11,4 e OM = 137,7 ± 10,4; e c distância percorrida (metros: NO = 1.194,9 ± 427,7; O = 503,2 ± 437,5 e OM = 399,9 ± 185,1. CONCLUSÃO: O LiVFC se mostrou efetivo para avaliação da CFCR e poderá vir a ser aplicado como método alternativo à ergoespirometria em determinadas situações.

  9. Bootstrap Hypothesis Testing

    OpenAIRE

    MacKinnon, James G.

    2007-01-01

    This paper surveys bootstrap and Monte Carlo methods for testing hypotheses in econometrics. Several different ways of computing bootstrap P values are discussed, including the double bootstrap and the fast double bootstrap. It is emphasized that there are many different procedures for generating bootstrap samples for regression models and other types of model. As an illustration, a simulation experiment examines the performance of several methods of bootstrapping the supF test for structural...

  10. Confiabilidade de instrumentos diagnósticos: estudo do inventário de sintomas psiquiátricos do DSM-III aplicado em amostra populacional

    Directory of Open Access Journals (Sweden)

    Sérgio Baxter Andreoli

    2001-12-01

    Full Text Available O objetivo foi estudar a confiabilidade do inventário de sintomas psiquiátricos do DSM-III aplicado em amostras representativas da população geral de três cidades brasileiras. Foram utilizados os métodos do entrevistador-observador e de consistência interna para medir a confiabilidade. Os diagnósticos de ansiedade generalizada, na vida (k = 0,46, no ano (k = 1,00, depressão na vida (k = 0,77 e os diagnósticos de abuso e dependência de álcool na vida (k = 1,00 foram confiáveis de forma consistente nos dois métodos empregados. Os diagnósticos de agorafobia (k = 1,00, fobia simples (k = 0,77, transtorno psicótico não esquizofrênico (k = 1,00 e o de fatores psicológicos que afetam o físico (1,00, todos feitos para a vida, apresentaram confiabilidade excelente medidos por meio do Kappa. O principal problema de medir a confiabilidade em estudos populacionais é a baixa prevalência de alguns diagnósticos que resulta em uma pequena variabilidade nas respostas positivas, o que impossibilita o cálculo do Kappa. Por causa disso, apenas 11 dos 39 diagnósticos que compõem o inventário puderam ser examinados. Recomenda-se a utilização do método de teste e re-teste com um tempo curto entre as entrevistas para diminuir esse problema.

  11. Confiabilidade de instrumentos diagnósticos: estudo do inventário de sintomas psiquiátricos do DSM-III aplicado em amostra populacional

    Directory of Open Access Journals (Sweden)

    Andreoli Sérgio Baxter

    2001-01-01

    Full Text Available O objetivo foi estudar a confiabilidade do inventário de sintomas psiquiátricos do DSM-III aplicado em amostras representativas da população geral de três cidades brasileiras. Foram utilizados os métodos do entrevistador-observador e de consistência interna para medir a confiabilidade. Os diagnósticos de ansiedade generalizada, na vida (k = 0,46, no ano (k = 1,00, depressão na vida (k = 0,77 e os diagnósticos de abuso e dependência de álcool na vida (k = 1,00 foram confiáveis de forma consistente nos dois métodos empregados. Os diagnósticos de agorafobia (k = 1,00, fobia simples (k = 0,77, transtorno psicótico não esquizofrênico (k = 1,00 e o de fatores psicológicos que afetam o físico (1,00, todos feitos para a vida, apresentaram confiabilidade excelente medidos por meio do Kappa. O principal problema de medir a confiabilidade em estudos populacionais é a baixa prevalência de alguns diagnósticos que resulta em uma pequena variabilidade nas respostas positivas, o que impossibilita o cálculo do Kappa. Por causa disso, apenas 11 dos 39 diagnósticos que compõem o inventário puderam ser examinados. Recomenda-se a utilização do método de teste e re-teste com um tempo curto entre as entrevistas para diminuir esse problema.

  12. Maximização do teor de carbono fixo em biocarvão aplicado ao sequestro de carbono

    Directory of Open Access Journals (Sweden)

    Alessandra L. da Róz

    2015-08-01

    Full Text Available RESUMOA emissão de dióxido de carbono é, atualmente, a principal causa do aquecimento global, devido ao efeito estufa. Ao redor do planeta pesquisadores têm-se esforçado na busca de soluções viáveis para o problema; com isto, o biocarvão está entre as mais recentes propostas de mitigação das mudanças climáticas em razão da sua simplicidade e eficiência. Desta forma, este trabalho teve, por objetivo, maximizar o teor de carbono fixo na produção de biocarvão. Para isso, analisaram-se sete tratamentos, temperaturas de pirólise: 200, 250, 300, 350, 400, 450 e 500 °C. A partir do rendimento gravimétrico de produção e do teor de carbono fixo calcularam-se os respectivos fatores de rendimento gravimétrico para cada tratamento, os quais indicam em qual temperatura se tem a maior quantidade de carbono fixo em função do biocarvão produzido. A pirólise com temperatura máxima de 300 °C indicou o maior fator de rendimento gravimétrico, atingindo 0,22672 C/biocarvão.

  13. Mobilidade e persistência de herbicidas aplicados em pré-emergência em diferentes solos Mobility and persistence of herbicides applied in pre-emergence on different soils

    Directory of Open Access Journals (Sweden)

    P.A. Monquero

    2008-06-01

    Full Text Available O objetivo deste ensaio foi verificar a mobilidade e persistência de herbicidas aplicados em pré-emergência em diferentes solos e quantidades de palha de cana-de-açúcar. Os herbicidas ametryn + clomazone (1.500 + 1.000 g i.a. ha-1, isoxaflutole (187,5 g i.a. ha-1 e diuron + hexazinone (1.170 + 330 g i.a. ha-1 foram aplicados em solo com textura argilosa e média nas seguintes condições: aplicação sobre 10 e 15 t ha-1 de palha com posterior simulação de chuva; simulação de chuva sobre o solo seguida da aplicação dos herbicidas, sendo coberto posteriormente com palha seca (10 t ha-1; aplicação dos herbicidas no solo sem palha; e testemunha. Aos 10, 20, 40 e 60 dias após aplicação dos herbicidas (DAA, foram semeados como bioindicadores sorgo e pepino, que foram avaliados com relação à fitotoxicidade aos 21 dias após emergência. A mistura ametryn + clomazone aplicada diretamente no solo controlou o bioindicador até 40 DAA, entretanto, após esse período, o efeito residual foi menor. A palha de cana-de-açúcar afetou negativamente o desempenho deste produto. O herbicida isoxaflutole aplicado diretamente no solo apresentou efeito residual até 60 DAA, com 82,5 e 77,5% de controle do bioindicador, em solos com textura argilosa e média, respectivamente; a presença de 10 e 15 t ha-1 de palha não alterou sua eficácia até 20 DAA. Para diuron + hexazinone aplicados no solo sem a presença de palha, verificou-se persistência até 60 DAA, principalmente em solo com textura argilosa; a deposição de 15 t ha-1 de palha reduziu a eficácia desta mistura.The objective of this work was to verify the mobility and persistence of herbicides applied in pre-emergence on different soils and amounts of sugarcane straw. The herbicides ametryn + clomazone (1,500 + 1,000 g i.a. ha-1, isoxaflutole (187,5 g.i.a. ha-1 and diuron + hexazinone (1,170 + 330 g i.a. ha-1 were applied in soil with clayey and medium texture under the following

  14. Mobile-first Bootstrap

    CERN Document Server

    Magno, Alexandre

    2013-01-01

    A practical, step-by-step tutorial on developing websites for mobile using Bootstrap.This book is for anyone who wants to get acquainted with the new features available in Bootstrap 3 and who wants to develop websites with the mobile-first feature of Bootstrap. The reader should have a basic knowledge of Bootstrap as a frontend framework.

  15. Sensoriamento remoto multifonte aplicado na detecção do fitoplâncton em águas interiores

    OpenAIRE

    Rejane E. Cicerelli; Maria de L. B. T. Galo

    2015-01-01

    Florações de fitoplanctôn podem constituir em riscos à saúde humana e biota aquática, sendo necessários o monitoramento da comunidade fitoplanctônica e a adoção de mecanismos visando à prevenção de sua ocorrência. Neste contexto métodos tradicionais de monitoramento podem ser mais efetivos se complementados por abordagens que utilizam as propriedades ópticas dos pigmentos fitoplanctônicos por meio do Sensoriamento Remoto. Com o objetivo de avaliar o potencial de dados espectrais multifonte na...

  16. DNA forense aplicado na identificação de vítimas de crimes em Pernambuco, Brasil

    Directory of Open Access Journals (Sweden)

    M.H.F. Ekert

    2016-07-01

    Full Text Available Introdução: A identificação humana por DNA é atualmente considerada crucial para a resolução de situações envolvendo matéria penal, bem como aquelas relacionados à paternidade e continua revolucionando as áreas jurídicas e penais. As principais regiões polimórficas de DNA usados na rotina forense são os STRs (Short Tandem Repeats presentes nos cromossomos autossômicos. Objetivo: Este estudo teve como objetivo identificar o perfil das vítimas afetadas por vários tipos de crimes ocorridos em Pernambuco. Materiais e Métodos: O Laboratório de Perícia e Pesquisa em Genética Forense (LPPGF proveu 125 casos de vários tipos de crimes ocorridos em Pernambuco entre 2012 e 2014. A verificação de identificação humana por amostras de músculo e osso foi realizada por amplificação de DNA e genotipagem pela alimentação do sistema Plex Fusion (24 loci STR e ABI PRISM 3500 HID respectivamente. As análises estatísticas foram realizadas pelos softwares: "famílias" e "patcan". Resultados: O LPPGF recebeu dois tipos de amostras biológicas para os ensaios de identificação genética humana: tecido ósseo (52,8% e o tecido muscular (47,2%. A alta prevalência de casos em aberto (47,2% e homicídio (42,4%, tanto na área metropolitana, quanto no interior, alerta a necessidade de implementar programas sociais de prevenção e qualidade de vida, além da necessidade de mais celeridade nas investigações policiais. Conclusões: A abordagem genética para identificação humana, principalmente vítimas de crimes, é uma condição importantíssima para a resolução de qualquer tipo de processo criminal e reduzir ainda mais a agonia vivida por famílias que tiveram seus entes queridos desaparecidos.

  17. Bootstrap inference in econometrics

    OpenAIRE

    James G. MacKinnon

    2002-01-01

    The astonishing increase in computer performance over the past two decades has made it possible for economists to base many statistical inferences on simulated, or bootstrap, distributions rather than on distributions obtained from asymptotic theory. In this paper, I review some of the basic ideas of bootstrap inference. I discuss Monte Carlo tests, several types of bootstrap test, and bootstrap confidence intervals. Although bootstrapping often works well, it does not do so in every case.

  18. Weed control in young coffee plantations through post emergence herbicide application onto total area Controle de plantas daninhas em cafezais recém-implantados, com herbicidas aplicados em pós-emergência em área total

    Directory of Open Access Journals (Sweden)

    C.P. Ronchi

    2004-12-01

    at doses recommended for bean crop, these herbicides may be applied to control weeds in coffee and bean intercropping systems by spraying the entire area.Este trabalho foi realizado com o objetivo de investigar, em campo, a eficiência de vários herbicidas aplicados em pós-emergência em área total no controle de plantas daninhas, em cafezais recém-implantados e no consórcio de café e feijão, assim como seus efeitos sobre essas culturas. Mudas de Coffea arabica, cultivar Catuaí Vermelho, com quatro a seis pares de folhas foram transplantadas para o campo e cultivadas segundo práticas agronômicas usuais. O consórcio de café e feijão foi obtido por meio do plantio de três linhas de feijão nas entrelinhas do cafezal. Quando os herbicidas foram aplicados sobre as culturas, as plantas de café estavam com seis a dez pares de folhas, as de feijão com três folíolos e as plantas daninhas no estádio inicial de desenvolvimento. Fluazifop-p-butil e clethodim foram seletivos às plantas de café e controlaram eficientemente Brachiaria plantaginea e Digitaria horizontalis. Plantas daninhas dicotiledôneas (Amaranthus retroflexus, Bidens pilosa, Coronopus didymus, Emilia sonchifolia, Galinsoga parviflora, Ipomoea grandifolia, Lepidium virginicum e Raphanus raphanistrum foram controladas eficientemente por aplicações isoladas de fomesafen, flazasulfuron e oxyfluorfen, com exceção de B. pilosa, C. didymus e R. raphanistrum para o oxyfluorfen. Aplicações seqüenciais com intervalos de sete dias de fomesafen + fluazifop-p-butil ou clethodim, e as duas misturas comerciais de fomesafen + fluazifop-p-butil controlaram simultaneamente ambos os tipos de plantas daninhas. Cyperus rotundus foi controlada apenas por flazasulfuron. Com exceção de fluazifop-p-butil e clethodim todos os demais tratamentos herbicidas provocaram apenas leves injúrias às folhas mais novas das plantas de café. Contudo, o crescimento das plantas não foi prejudicado, de forma que tanto a

  19. Cuidar em Humanitude: estudo aplicado em cuidados continuados El cuidado en Humanitude: estudio aplicado a un proceso continuo de atención Caring in Humanitude: study applied to a continuum of care

    Directory of Open Access Journals (Sweden)

    Mário Simões

    2012-03-01

    Full Text Available O primeiro estudo científico, sobre o método de cuidados de Humanitude de Gineste e Marescotti (MGM, foi desenvolvido em Portugal por Simões, Rodrigues e Salgueiro (2011b. Em continuidade, este estudo de investigação ação envolve uma equipa de cuidadores e uma população de idosos dependentes internados, de uma Unidade de Cuidados Continuados Integrados (UCCI, com o objetivo de desenvolver as competências dos cuidadores na aplicação do MGM, em contexto, e avaliar as respostas físicas, cognitivas e emocionais dos doentes cuidados de acordo com esse método. Os instrumentos de medida incluem as duas escalas de perceção do valor e aplicabilidade do MGM, utilizadas no estudo anterior, e uma grelha de observação direta sistematizada, validada para este estudo. Os resultados de diagnóstico inicial são coincidentes com o estudo anterior, indicando uma perceção elevada de valor e aplicação na prática clínica da sequência de procedimentos, no entanto os dados observacionais revelaram grandes desvios entre perceção e realização efetiva. Neste artigo descreve-se, com algum pormenor, o percurso das primeiras etapas deste projeto, cujos resultados orientam para as etapas seguintes, seguindo a metodologia de investigação ação associada (IAA.El primer estudio científico sobre el método de atención Humanitude de Gineste y Marescotti (MGM, se desarrolló en Portugal por Simões Rodrigues y Salgueiro, (2011b. De forma continua, este estudio de investigación-acción, implica a un equipo de médicos y a una población de adultos mayores dependientes hospitalizados en una Unidad de Atención Continuada (UCCI, con el objetivo de desarrollar las habilidades de los cuidadores en la aplicación del MGM, en contexto, y evaluar las respuestas físicas, cognitivas y emocionales de los usuarios según este método. Los instrumentos de medición incluyen dos escalas de percepción del valor y de la aplicabilidad de la MGM, utilizadas en

  20. Seletividade de herbicidas aplicados em pré-emergência na cultura de cana-de-açúcar tratada com nematicidas Selectivity of pre-emergence herbicides to sugarcane treated with nematicides

    OpenAIRE

    E. Negrisoli; E.D. Velini; G.R. Tofoli; A.L Cavenaghi; Martins, D; J.L. Morelli; A.G.F. Costa

    2004-01-01

    O objetivo do trabalho foi estudar a seletividade de herbicidas para a cultura da cana-de-açúcar quando aplicado em culturas tratadas com nematicidas. O experimento foi instalado em área pertencente à Usina São José, município de Borebi-SP, ano agrícola de 2000/01. A variedade de cana-de-açúcar utilizada foi a RB855113. Utilizou-se o delineamento experimental de blocos ao acaso em parcelas subdivididas, com quatro repetições. Cada parcela correspondeu a 27 linhas de 10,0 m, espaçadas em 1,0 m...

  1. Seletividade de herbicidas, aplicados em pós-emergência, às plantas de alfafa Selectivity of applied port-emergence herbicides in the alfafa plants

    Directory of Open Access Journals (Sweden)

    Gláucia de Mello

    2000-08-01

    Full Text Available Foram conduzidos doi experimentos na UNESP/Jaboticabal, em casa-de-vegetação, com o objetivo de avaliar-se a toxicidade de diferentes herbicidas, aplicados em pós-emergênica, às plantas de alfafa. No primeiro, utilizou-se de um delineamento experimental com parcelas inteiramente casualizadas para avaliar-se os efeitos fitotóxicos dos seguintes herbicidas: MSMA, clethodim + óleo mineral, lactofen, fluazifop-pbutil, fomesafen + óleo mineral haloxyfop-methyl + óleo mineral, fenoxaprop-ethyl, chlorimuronethyl, halosulfuron + óleo mineral, nicosulfuron, acifluorfen, imazethapyr, bentazon + óleo mineral e cyanazine + simazine, todos em só dose. Foram feitas avaliações da fitotoxicidade por meio de notas, atribuídas visualmente, em função dos sintomas constatados nas plantas. A altura das plantas e o peso da matéria seca da parte área foram avaliadas no período de desenvolvimento inicial e após a primeira rebrota. No segundo experimento foi seguido mesmo esquema de instalação e condução do anterior, após escolherse os herbicidas e doses, sendo eles, o MSMA, chlorimuron-ethyl, imazethapyr, bentazon + óleo mineral, clethodim, clethodim + óleo mineral e bentazon + MSMA. Os herbicidas mais seletivos às plantas de alfafa foram haloxyfop-methyl, fluazifop-p-butil, fenoxaprop-ethyl, MSMA, imazethapyr, bentazon e clethodim isolado e adicionado de óleo mineral.Two experiments were carried out in a greenhouse, belonging to the Departamento de Defesa Fitissanitária da Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal/UNESP, with the purpose of evaluating the selectivity of different used post-emergence herbicides on alfafa plants. The experimental design was completely randomized to evaluate the phytotoxical effects of following herbicides: MSMA, clethodim plus mineral oil, lactofen, fluazifop-p-butil, fomesafen plus mineral oil, haloxyfop-methyl plus mineral oil, chlorimuron-ethyl, halosulfuron plus mineral oil

  2. Bootstrap Methods in Econometrics

    OpenAIRE

    MacKinnon, James G.

    2006-01-01

    There are many bootstrap methods that can be used for econometric analysis. In certain circumstances, such as regression models with independent and identically distributed error terms, appropriately chosen bootstrap methods generally work very well. However, there are many other cases, such as regression models with dependent errors, in which bootstrap methods do not always work well. This paper discusses a large number of bootstrap methods that can be useful in econometrics. Applications to...

  3. Bootstrap in Econometrics

    OpenAIRE

    Mitterpach, Róbert

    2012-01-01

    Aim of this thesis is to introduce the reader to the basic bootstrap techniques used in econometrics, to present their variations and importance. Results of the ordinary least squares model, residual bootstrap and case resampling bootstrap will be presented and compared on cross-sectional data and time series from small numbered random subsample from the available data. Bootstrap was shown to improve numerical performance of ordinary least squares model.

  4. Fitotoxidade de herbicidas aplicados em pós-emergência na fase inicial da cultura do milho Toxicity of herbicides post emergents at maize crop initial phase

    Directory of Open Access Journals (Sweden)

    Paulo C. Magalhães

    2000-08-01

    Full Text Available A aplicação de herbicidas em pósemergência inicial e em pós-emergência dirigida pode causar injúrias às plantas de milho, quando estas são atingidas por produtos não totalmente seletivos. Como esses herbicidas são basicamente bloqueadores de processos metabólicos, surge a dúvida de quais serão os efeitos dessas injúrias na produção final de grãos de milho. Assim, o objetivo deste trabalho foi estudar o efeito da fitotoxidade causada pela aplicação de herbicidas na fase inicial e na pós-emergência tardia da cultura e o seu efeito na produção de grãos. Foi utilizado o híbrido BRS 3123, em 12 tratamentos repetidos 4 vezes. Esses tratamentos consistiram da aplicação dos seguintes herbicidas: cyanazine + simazine + assist, aplicados nos estádios de crescimentos de 4 e 6 folhas e paraquat + extravon e ametryn + assist, aplicados no estádio de 12 folhas, em jato dirigido. Foram incluídos também testemunhas com e sem capinas, além dos tratamentos com retirada mecânica das folhas do 1o e do 1o ao 3o pares de folha. Foram avaliados: área foliar, matéria seca, teor de clorofila nas folhas, altura da planta e da inserção de espigas, diâmetro do colmo, índice de espigas, peso de 1000 grãos e produção de grãos. Observou-se que no no primeiro ano agrícola (94/95, as variáveis de crescimento não foram afetadas pelos tratamentos, ao passo que no ano seguinte, o melhor desenvolvimento das plantas foi obtido com a aplicação de cyanazine + simazine, enquanto que paraquat + extravon, ametryn + assist e testemunha sem capina, (devido ao efeito de matocompetição, resultaram nos piores tratamentos até a floração do milho. A maior produção de espigas e grãos no primeiro ano foi obtida com o tratamento cyanazine + simazine + assist, enquanto que, no segundo ano, paraquat + extravon e ametryn + assist proporcionaram as maiores produções, apesar das injúrias observadas na área foliar.Herbicide application at post

  5. Atividade residual de herbicidas aplicados ao solo em relação ao controle de quatro espécies de Amaranthus Residual activity of herbicides applied to the soil in relation to control of four Amaranthus Species

    OpenAIRE

    M.A. Raimondi; R.S. Oliveira Jr; Constantin, J; D.F. Biffe; J.G.Z Arantes; L.H. Franchini; F.A Rios; E. Blainski; J.B Osipe

    2010-01-01

    Herbicidas aplicados em pré-emergência normalmente apresentam atividade residual no solo, controlando os primeiros fluxos germinativos das plantas daninhas e prevenindo a matocompetição inicial. O objetivo deste trabalho foi verificar o período de atividade residual proporcionado por doses de herbicidas suficientes para o controle pontual de 95% (C95) das espécies Amaranthus hybridus, A. lividus, A. spinosus e A. viridis, além de avaliar doses recomendadas desses herbicidas. O trabalho foi re...

  6. Tolerância de mudas de café a herbicidas aplicados em pós-emergência Tolerance of coffee plants to post emergence herbicide application

    OpenAIRE

    C.P. Ronchi; A.A. Silva

    2003-01-01

    Este trabalho teve como objetivo avaliar a tolerância de mudas de café à aplicação de herbicidas em pós-emergência. Flumiozaxin, sulfentrazone, flazasulfuron, clethodim, fluazifop-p-butil, imazamox, bentazon, fomesafen, lactofen, oxyfluorfen, chlorimuron-ethil, metribuzin e também as misturas de fluazifop-p-butil + fomesafen e de nicosulfuron + atrazine foram aplicados diretamente sobre o topo das plantas, 15 dias após o transplantio das mudas de café para os vasos (3,0 L). Foram feitas avali...

  7. Seletividade de herbicidas aplicados em pré-emergência, isolados e em misturas, na cultura do algodão = Selective of applied herbicides in pre-emergency, isolated and in mixtures, in the culture of the cotton.

    Directory of Open Access Journals (Sweden)

    Miriam Hiroko Inoue

    2012-08-01

    Full Text Available A cultura do algodão tem grande importância econômica e social, visto que é a fibra mais utilizada no setor têxtil. Contudo, apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto objetivouse com este trabalho avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a variedade FMT-701, nas localidades de Diamantino-MT e Campos de Júlio-MT. O delineamento experimental utilizado foiem blocos casualizados com 16 tratamentos e 4 repetições. Para avaliar a seletividade foram realizadas avaliações de alturaaos 36, 66 e 150 dias após a aplicação (DAA, fitointoxicação aos 14, 21, 29 e 36 DAA, estande aos 21 e 49 DAA, número de maçãs aos 141 DAA e produtividade do algodão em caroço aos 193 DAA. Os resultados indicaram que grande parte dos tratamentos causou injúrias na fase inicial da cultura e alguns tratamentos também proporcionaram menor altura de plantas em determinadas avaliações. Verificou-se ainda que os tratamentos não proporcionaram diferença significativa no estande de plantas, no número de maçãs e nem na produtividade de algodão em caroço, evidenciando que todos os tratamentos avaliados podem ser utilizados no manejo de plantas daninhas.The culture of the cotton has great economic and social importance, because it is the fiber more frequently used in the textile section. However, the crop has high sensibility to weed and there are few selective herbicides for this crop. In this context, the objective of this study was to evaluate the selectivity of applied herbicides in pre-emergency on the culture of the cotton. The herbicides alachlor, S-metolachlor, diuron, prometryne, trifluralin and oxyfluorfen were separately applied and in mixtures with the variety FMT-701, in the places of Diamantino

  8. Propriedades psicométricas de indicador subjetivo aplicado em crianças Psycometrics properties of subjetive indicator in children

    Directory of Open Access Journals (Sweden)

    Christiane Alves Ferreira

    2004-06-01

    Full Text Available OBJETIVO: Avaliar as propriedades psicométricas do Oral Heath Impact Profile (OHIP-14 para mensurar a condição de saúde bucal. MÉTODOS: Foram utilizados dados secundários de um inquérito epidemiológico realizado em 2001 pela Secretaria da Saúde do município de Sabará, MG, que consistiram de 312 formulários de exames da cárie dentária e de questionários de necessidade percebida (OHIP, referentes escolares de 12 anos, da rede pública. A confiabilidade do OHIP-14 foi avaliada utilizando os coeficientes alfa de Cronbach e correlação intraclasse. Para avaliação da validade de conteúdo foram realizadas a correlação de Pearson e regressão logística e para avaliar a validade de constructo foram realizados o teste "t" de Student e o de Tukey Kramer. RESULTADOS: A perda dos participantes foi baixa (entre 85 e 100%. A prevalência de cárie foi muito baixa sendo que 59,0% da amostra não apresentou cárie detectável. O modelo de regressão logística indicou valores de predição altos para declaração de necessidade de tratamento e médios para percepção de cárie dentária. A comparação entre diferentes escores médios do OHIP, de acordo com três categorias do índice de superfícies cariadas perdidas e obturadas (CPO-S, indicou diferença significante apenas para as categorias incapacidade social e deficiência. CONCLUSÕES: Os resultados indicam que o adolescente não relatou alta prevalência de doença bucal percebida. O OHIP está associado à necessidade percebida de tratamento, à declaração da presença de cárie dentária e ao aumento do índice CPO-S. Os resultados sugerem que o OHIP apresenta boas propriedades psicométricas quando aplicado em crianças, indicando ser um instrumento promissor para rastreamento de grupos prioritários para acesso ao serviço.OBJECTIVE: To evaluate the psychometric properties of the Oral Heath Impact Profile (OHIP-14 to measure oral health in children. METHODS: The OHIP-14

  9. Comportamento do herbicida metribuzin, aplicado isolado e em mistura com outros herbicidas, no controle de plantas daninhas em cafeeiros novos por dois anos consecutivos Effect of metribuzin, sprayed alone or in mixture with another herbicides, for weed control on young coffee trees, during two years

    OpenAIRE

    L.S.P. Cruz; C.A.L. Santos

    1985-01-01

    Para se conhecer o comportamento do herbicida metribuzin, aplicado isolaso ou em mistura com outros herbicidas residuais (napropamide, pendimethalin, alchlor, oryzalin e diuron) no controle de plantas daninhas que comumente infestam cafeeiros em formação, foi conduzido um experimento de campo onde esse herbicida a 0,28; 0,42; 0,56 e 0,70 kg/ha em mistura com napropamide a 4,00 kg/ha pendimethalin a 1,00 kg/ha, alachlor a 2,40kg/ha, oryzalin a 1,50 kg/ha ou com diuron a 1,20 kg/ha, comparado c...

  10. The Bayesian Bootstrap

    OpenAIRE

    Rubin, Donald B.

    1981-01-01

    The Bayesian bootstrap is the Bayesian analogue of the bootstrap. Instead of simulating the sampling distribution of a statistic estimating a parameter, the Bayesian bootstrap simulates the posterior distribution of the parameter; operationally and inferentially the methods are quite similar. Because both methods of drawing inferences are based on somewhat peculiar model assumptions and the resulting inferences are generally sensitive to these assumptions, neither method should be applied wit...

  11. Nonparametric bootstrap prediction

    OpenAIRE

    Fushiki, Tadayoshi; Komaki, Fumiyasu; Aihara, Kazuyuki

    2005-01-01

    Ensemble learning has recently been intensively studied in the field of machine learning. `Bagging' is a method of ensemble learning and uses bootstrap data to construct various predictors. The required prediction is then obtained by averaging the predictors. Harris proposed using this technique with the parametric bootstrap predictive distribution to construct predictive distributions, and showed that the parametric bootstrap predictive distribution gives asymptotically better prediction tha...

  12. Bootstrapping Macroeconometric Models

    OpenAIRE

    2001-01-01

    This paper outlines a bootstrapping approach to the estimation and analysis of macroeconometric models. It integrates for dynamic, nonlinear, simultaneous equation models the bootstrapping approach to evaluating estimators initiated by Efron (1979) and the stochastic simulation approach to evaluating models' properties initiated by Adelman and Adelman (1959). It also estimates for a particular model the gain in coverage accuracy from using bootstrap confidence intervals over asymptotic confid...

  13. Efeito de dinitramine, aplicado em pré-plantio incorporado, em cultura de soja (Glycine max (L. Merril Effect of dinitramine, pre-planting incorporated, on soybean crop (Glycine max L. Merr.

    Directory of Open Access Journals (Sweden)

    L. S. P. Cruz

    1979-12-01

    Full Text Available Com a finalidade de se obter maiores conhecimentos sobre a ação do herbicida dinitramine no controle de plantas daninhas em culturas de soja, e principalmente, sua influência sobre a própria cultura, foi conduzido um experimento de campo em 1974/75, no município de Cristais Paulista, SP. O ensaio compunha-se de dez tratamentos distribuídos em blocos ao acaso, com quatro repetições, onde o dinitramine foi aplicado nas doses de 0,375 kg e 0,575 kg/ha. Foram plantadas sementes dos cultivares Santa Rosa, IAC-2 e Mineira. Além das testemunhas sem herbicida constou do ensaio um tratamento com trifluralin a 0,720 kg/ha, plantado com o cultivar IAC-2. Em sub-parcelas havia diferenças de profundidade de incorporação dos herbicidas ao solo, a 0,07m e 0,15m. A população natural de plantas daninhas da área do experimento era representada por duas monocotiledõneas e duas dicotiledôneas, além de outras em pequeno número. As monocotiledõneas foram muito bem controladas por dinitramine nas duas doses e uma das dicotiledôneas também foi eficientemente controlada, porém, somente na dose maior. Trifluralin também deixou de controlar somente uma dicotiledõnea. A análise estatística do número de plantas de soja revelou diferenças significativas para dinitramine já em sua menor dose, para as três variedades de soja; porém, essa significãncia desapareceu na produção. Por outro lado verificou-se significãncia para a interação tratamento x incorporação, a qual foi detectado ser o resultado positivo da incorporação rasa com a dose menor de dinitramine.They efficiency of dinitramine on weed control and its effects on soybean plants, CV Santa Rosa, IAC-2 and Mineira, was studied in a field trial performed in 1974/75 in Cristais Paulista, SP. Dinitramine was applied at 0, 0,375 and 0,575 kg/ha, combined with all cultivars, and trifluralin at 0,720 kg, with IAC-2. Plots were split in two incorporation depths: 0,07 and 0,15m. Weed

  14. The Local Fractional Bootstrap

    DEFF Research Database (Denmark)

    Bennedsen, Mikkel; Hounyo, Ulrich; Lunde, Asger;

    new resampling method, the local fractional bootstrap, relies on simulating an auxiliary fractional Brownian motion that mimics the fine properties of high frequency differences of the Brownian semistationary process under the null hypothesis. We prove the first order validity of the bootstrap method...

  15. Seletividade de herbicidas aplicados em pré-emergência na cultura de cana-de-açúcar tratada com nematicidas Selectivity of pre-emergence herbicides to sugarcane treated with nematicides

    Directory of Open Access Journals (Sweden)

    E. Negrisoli

    2004-12-01

    Full Text Available O objetivo do trabalho foi estudar a seletividade de herbicidas para a cultura da cana-de-açúcar quando aplicado em culturas tratadas com nematicidas. O experimento foi instalado em área pertencente à Usina São José, município de Borebi-SP, ano agrícola de 2000/01. A variedade de cana-de-açúcar utilizada foi a RB855113. Utilizou-se o delineamento experimental de blocos ao acaso em parcelas subdivididas, com quatro repetições. Cada parcela correspondeu a 27 linhas de 10,0 m, espaçadas em 1,0 m, sendo dividida em três subparcelas. As parcelas corresponderam aos tratamentos com os herbicidas, e as subparcelas, à aplicação ou não dos nematicidas carbofuran (2,10 kg ha-1 e terbufós 2,25 kg ha��. Os herbicidas testados foram: tebuthiuron (1,12 kg ha-1, ametryne (1,75 kg ha¹, sulfentrazone (0,8 kg ha-1, metribuzin (1,92 kg ha-1, isoxaflutole (0,0525 kg ha¹, clomazone (1,25 kg ha¹, oxyfluorfen (0,36 kg ha-1 e azafenidin+hexazinone (0,1575 + 0,2025 kg ha-1, sendo todos aplicados em pré-emergência, além de uma parcela como testemunha. Os resultados obtidos evidenciaram que os herbicidas oxyfluorfen e azafenidin+hexazinone causaram os maiores níveis de fitotoxicidade na cana-de-açúcar, independentemente do uso dos nematicidas carbofuran e terbufós. Os herbicidas tebuthiuron, ametryne, sulfentrazone, metribuzin, isoxaflutole, clomazone, oxyfluorfen e azafenidin+hexazinone, aplicados em doses representativas das comercialmente utilizadas, mostraram-se seletivos à cana-de-açúcar, não afetando seu crescimento, sua produtividade e suas características tecnológicas. Os nematicidas não interferiram nos níveis de intoxicação provocados pelos herbicidas utilizados na cultura.The objective of this work was to study the selectivity of herbicides to sugarcane when applied in crops treated with nematicides. The experiment was carried out in Borebi, São Paulo-Brazil, during the growing season 2000/2001. The sugar cane variety

  16. Bootstrap confidence intervals

    OpenAIRE

    Thomas J. DiCiccio; Efron, Bradley

    1996-01-01

    This article surveys bootstrap methods for producing good approximate confidence intervals. The goal is to improve by an order of magnitude upon the accuracy of the standard intervals $\\hat{\\theta} \\pm z^{(\\alpha)} \\hat{\\sigma}$, in a way that allows routine application even to very complicated problems. Both theory and examples are used to show how this is done. The first seven sections provide a heuristic overview of four bootstrap confidence interval procedures: $BC_a$, bootstrap-t , ABC a...

  17. The Effective Bootstrap

    CERN Document Server

    Echeverri, Alejandro Castedo; Serone, Marco

    2016-01-01

    We study the numerical bounds obtained using a conformal-bootstrap method - advocated in ref. [1] but never implemented so far - where different points in the plane of conformal cross ratios $z$ and $\\bar z$ are sampled. In contrast to the most used method based on derivatives evaluated at the symmetric point $z=\\bar z =1/2$, we can consistently "integrate out" higher-dimensional operators and get a reduced simpler, and faster to solve, set of bootstrap equations. We test this "effective" bootstrap by studying the 3D Ising and $O(n)$ vector models and bounds on generic 4D CFTs, for which extensive results are already available in the literature. We also determine the scaling dimensions of certain scalar operators in the $O(n)$ vector models, with $n=2,3,4$, which have not yet been computed using bootstrap techniques.

  18. Dynamics of bootstrap percolation

    Indian Academy of Sciences (India)

    Prabodh Shukla

    2008-08-01

    Bootstrap percolation transition may be first order or second order, or it may have a mixed character where a first-order drop in the order parameter is preceded by critical fluctuations. Recent studies have indicated that the mixed transition is characterized by power-law avalanches, while the continuous transition is characterized by truncated avalanches in a related sequential bootstrap process. We explain this behaviour on the basis of an analytical and numerical study of the avalanche distributions on a Bethe lattice.

  19. Bootstrap percolation with inhibition

    OpenAIRE

    Einarsson, Hafsteinn; Lengler, Johannes; Panagiotou, Konstantinos; Mousset, Frank; Steger, Angelika

    2014-01-01

    Bootstrap percolation is a prominent framework for studying the spreading of activity on a graph. We begin with an initial set of active vertices. The process then proceeds in rounds, and further vertices become active as soon as they have a certain number of active neighbors. A recurring feature in bootstrap percolation theory is an `all-or-nothing' phenomenon: either the size of the starting set is so small that the process stops very soon, or it percolates (almost) completely. Motivated by...

  20. Comportamento de cultivares de soja [Glycine max (L. Merrill] em resposta ao metribuzin aplicado em diferentes doses Response of soybean [Glycine max (L. Merrill] cultivars to rates of metribuzin

    Directory of Open Access Journals (Sweden)

    J.A.R.O. Velloso

    1980-06-01

    Full Text Available Durante o ano agrícola de 1978/79, foi realizado um experimento a campo, na re gião da Depressão Central do Rio Grande do Sul, com o objetivo de conhecer o comportamento das cultivares de soja BR1, Bragg, Davis, IAS4, IAS5, Paraná e Planalto em relação ao metribuzin aplicado em pré-emergência nas doses de 0, 490 e 980 g/ha. Os efeitos dos tratamentos foram estimados através de avaliação visual de fitotoxicidade, contagem da população de plantas, determinações do peso seco da parte aérea e do número de grãos e obtenção do rendimento de grãos. Para a maioria das variáveis em estudo, constatou-se que ocorreram reduções proporcionais aos acréscimos das doses do herbicida. Os resultados da avaliação visual de fitotoxicidade mostraram que houve diferenças significativas entre os tratamentos de doses, tendo as cultivares Bragg e Davis demonstrado o menor efeito fito-tóxico, enquanto BR1 foi a que apresentou maior grau de injúria. Quanto ao rendimento de grãos alcançado pelas cultivares, foi constatado que Bragg comportou-se como altamente tolerante; BR1 e Davis como moderadamente tolerantes; IAS5 como intermediária e Paraná, Planalto e IAS4 como moderadamente suscetíveis.A field experiment was conducted during the 1978/79 growing season at the Central Depression Region of Rio Grande do Sul, Brazil, in order to evaluate the response soybean cultivars BR1, Bragg, Davis, IAS4, IAS5, Paraná, and Planalto to metribuzin applied in pre-emergence at rates of 0, 490 and 980 g/ha. The effects of the treatments were evaluated through visual rating of phytotoxicity, counting of soybean population, and determinations of dry weight of soybean stems, number of grains per unit area and grain yield. For most of the variables measured there were reductions proportional to increasing rates of metribuzin appl ied. Results of visual evaluation of soybean injury showed statistical differences among rates of the herbicide, being Bragg and

  1. Geoprocessing applied to the phytosociological survey in permanent plots El geo-procesamiento aplicado al levantamiento fito-sociológico en parcelas permanentes Geoprocessamento aplicado ao levantamento fitossociológico em parcelas permanentes

    Directory of Open Access Journals (Sweden)

    Luiz Gilberto Bertotti

    2009-12-01

    cadastrales que permita acompañar el análisis del desarrollo de la vegetación local, lo que permitió  incluso acompañar el estudio de los árboles dentro de una escala temporal mostrando la evolución del fragmento de la floresta estudiada.O objetivo deste trabalho foi a criação de um banco de dados de georreferenciado para acompanhar as mudanças fitossociológicas dos indivíduos arbóreos ao longo do tempo e sua distribuição geográfica na área de estudo. Para o levantamento fitossociológico na área de estudo foram demarcadas parcelas permanentes ao longo das planícies de inundação dos rios Carro Quebrado e Cascavel, localizados no Campus CEDETEG da Universidade Estadual do Centro-Oeste (UNICENTRO, no município de Guarapuava, Estado do Paraná.  Em cada parcela foram avaliados atributos como: PS = posição sociológica; CC = classe de copa; Ca = características das árvores; CQT = condição de qualidade de tronco; Cs = condições.  Essas parcelas foram espacializadas a partir da utilização do Sistema de Posicionamento Global (GPS e os dados foram exportados para o software SPRING com a finalidade de construir um banco de dados cadastral, visando o acompanhamento e a análise do desenvolvimento da vegetação local. A geração do banco de dados permitiu acompanhar o desenvolvimento das árvores dentro de uma escala temporal, mostrando a evolução do fragmento de floresta estudado.

  2. Wild cluster bootstrap confidence intervals

    OpenAIRE

    MacKinnon, James G.

    2014-01-01

    Confidence intervals based on cluster-robust covariance matrices can be constructed in many ways. In addition to conventional intervals obtained by inverting Wald (t) tests, the paper studies intervals obtained by inverting LM tests, studentized bootstrap intervals based on the wild cluster bootstrap, and restricted bootstrap intervals obtained by inverting bootstrap Wald and LM tests. It also studies the choice of an auxiliary distribution for the wild bootstrap, a modified covariance matrix...

  3. Breakdown theory for bootstrap quantiles

    OpenAIRE

    Singh, Kesar

    1998-01-01

    A general formula for computing the breakdown point in robustness for the $t$th bootstrap quantile of a statistic $T_n$ is obtained. The answer depends on $t$ and the breakdown point of $T_n$. Since the bootstrap quantiles are vital ingredients of bootstrap confidence intervals, the theory has implications pertaining to robustness of bootstrap confidence intervals. For certain $L$ and $M$ estimators, a robustification of bootstrap is suggested via the notion of Winsorization.

  4. Evaluation of the virtual learning object "Diagnostic reasoning in nursing applied to preterm newborns" Evaluación del objeto virtual de aprendizaje "Raciocinio diagnóstico en enfermería aplicado al prematuro" Avaliação do objeto virtual de aprendizagem "Raciocínio diagnóstico em enfermagem aplicado ao prematuro"

    Directory of Open Access Journals (Sweden)

    Fernanda dos Santos Nogueira de Góes

    2011-08-01

    de informática. Se considera que el producto desarrollado está adecuado para ser colocado a disposición para uso en la enseñanza de estudiantes y en la educación permanente de enfermeros sobre raciocinio diagnóstico en la elaboración de Diagnósticos de Enfermería aplicados al prematuro, dentro del marco pedagógico de la problematización.Vislumbrando o potencial de uso da informática, na formação e educação permanente em enfermagem, realizou-se o presente estudo com o objetivo de avaliar objeto virtual de aprendizagem raciocínio diagnóstico em enfermagem aplicado ao prematuro, em unidade de cuidado intermediário neonatal. Trata-se de estudo descritivo sobre a avaliação da aparência e conteúdo do objeto virtual, nos aspectos relacionados à apresentação, organização, usabilidade e impressão geral. Participaram peritos das áreas de informática (12 e enfermagem (31. Cada subitem dos instrumentos continha avaliação em escala Likert e espaço para inclusão de comentários/sugestões. Todos os itens foram avaliados positivamente por mais de 80% dos avaliadores, exceto o critério densidade informacional na avaliação dos profissionais de informática. Considera-se que o produto desenvolvido está adequado para ser disponibilizado para uso no ensino de estudantes e educação permanente de enfermeiros, sobre raciocínio diagnóstico na elaboração de diagnósticos de enfermagem, aplicados ao prematuro, inserido no referencial pedagógico da problematização.

  5. Detecção de emissão espontânea de luz em ensaios de colimetria aplicados ao monitoramento de efluentes sanitários Spontaneous light emission in coliforms test applied to wastewater monitoring

    Directory of Open Access Journals (Sweden)

    Samuel Ricardo dos Santos

    2011-03-01

    Full Text Available No presente trabalho avaliou-se o potencial do emprego da técnica biofotônica ao monitoramento da qualidade microbiológica de efluentes sanitários, por meio da detecção de emissão ultrafraca de luz em testes envolvendo bactéria do grupo coliforme. Foram acompanhados os padrões de emissão de luz em câmara escura com o uso de efluente doméstico, antes e após tratamento, incubados em meio nutritivo à base de lactose e lauril triptose. O controle foi efetuado com o uso de cepa de Escherichia coli (ATCC 25.922, tendo seu crescimento sido monitorado por emissão de luz em câmara escura com fotomultiplicador acoplado. Os dados demonstraram que o monitoramento microbiológico pode ser efetuado por meio técnica biofotônica, podendo ser aplicado, com respostas rápidas, ao monitoramento microbiológico de efluentes, por meio de testes envolvendo coliformes.The spontaneous light emission of living systems emerge as a promising methodology that applied to microbiological in monitoring water can lead to short-term analysis. The present study evaluated the potential of biophoton measurements applied to wastewater monitoring by using ultraweak light emission in coliform tests. The procedure is based on photon-counting measurements inside a dark-chamber, of wastewater samples, before and after treatment, inoculated in nutrient presence/absence medium (lactose and lauryl triptose broth. Strain of Escherichia coli (ATCC 25,922 was used in control tests by monitoring the light emission inside a dark-chamber with an acoplade photomultiplier. The data showed that microbiological monitoring can be done by photon-counting in real-time applied to microbiological wastewater monitoring using coliform test.

  6. Foliar biofertilizer applied in cover fertilization in the production of lettuce cv. Veronica El uso de bio-fertilizante foliar en la fertilización de cobertura de lechuga cv. Verónica Biofertilizante foliar aplicado em cobertura na produção de alface cv. Verônica.

    OpenAIRE

    Luniara Bastos dos Santos; Gilson Araújo de Freitas; Joseanny Cardoso da Silva; Jhansley Ferreira da Mata; Jucielle Cardoso da Silva; Miréia Aparecida Bezerra Pereira; Ildon Rodrigues do Nascimento

    2010-01-01

    O uso de biofertilizantes via foliar pode ser utilizado como suplementação da adubação aplicada no solo e na correção mais rápida de possíveis deficiências. Devido a esse fato, essa prática tem sido cada vez mais utilizada pelos produtores em espécies olerícolas, especialmente folhosas. O presente trabalho objetivou avaliar o desempenho de plantas de alface crespa (cv. Verônica) em resposta a doses de biofertilizante em diferentes concentrações aplicados via foliar. O...

  7. Temperature Corrected Bootstrap Algorithm

    Science.gov (United States)

    Comiso, Joey C.; Zwally, H. Jay

    1997-01-01

    A temperature corrected Bootstrap Algorithm has been developed using Nimbus-7 Scanning Multichannel Microwave Radiometer data in preparation to the upcoming AMSR instrument aboard ADEOS and EOS-PM. The procedure first calculates the effective surface emissivity using emissivities of ice and water at 6 GHz and a mixing formulation that utilizes ice concentrations derived using the current Bootstrap algorithm but using brightness temperatures from 6 GHz and 37 GHz channels. These effective emissivities are then used to calculate surface ice which in turn are used to convert the 18 GHz and 37 GHz brightness temperatures to emissivities. Ice concentrations are then derived using the same technique as with the Bootstrap algorithm but using emissivities instead of brightness temperatures. The results show significant improvement in the area where ice temperature is expected to vary considerably such as near the continental areas in the Antarctic, where the ice temperature is colder than average, and in marginal ice zones.

  8. Scalar-vector bootstrap

    Science.gov (United States)

    Rejon-Barrera, Fernando; Robbins, Daniel

    2016-01-01

    We work out all of the details required for implementation of the conformal bootstrap program applied to the four-point function of two scalars and two vectors in an abstract conformal field theory in arbitrary dimension. This includes a review of which tensor structures make appearances, a construction of the projectors onto the required mixed symmetry representations, and a computation of the conformal blocks for all possible operators which can be exchanged. These blocks are presented as differential operators acting upon the previously known scalar conformal blocks. Finally, we set up the bootstrap equations which implement crossing symmetry. Special attention is given to the case of conserved vectors, where several simplifications occur.

  9. Introduction to the Bootstrap World

    OpenAIRE

    Boos, Dennis D.

    2003-01-01

    The bootstrap has made a fundamental impact on how we carry out statistical inference in problems without analytic solutions. This fact is illustrated with examples and comments that emphasize the parametric bootstrap and hypothesis testing.

  10. Utilização de acetochlor e atrazine aplicados em mistura de tanque com dessecantes no sistema de plantio direto Reaction of the herbicides acetochlor and atrazine applied in tank mixtures with desiccants in no-till system

    Directory of Open Access Journals (Sweden)

    Benedito N. Rodrigues

    2000-08-01

    Full Text Available A mistura em tanque de herbicidas dessecantes com residuais tem sido utilizada com frequencia pelos agricultores no sistema de plantio direto. Sabe-se, no entanto, que alguns herbicidas residuais têm problemas de retenção na palha quando utilizados isoladamente em préemergência nesse sistema. O objetivo do presente trabalho, foi estudar o comportamento dos herbicidas residuais atrazine e acetochlor em mistura com dessecantes no manejo em plantio direto. Para tal, foi instalado um experimento em blocos ao acaso com parcelas subdivididas e quatro repetições. Os tratamentos, alocados na parcela, em número de nove, foram constituidos pelas seguintes misturas de herbicidas: 1 acetochlor + glyphosate; 2 acetochlor + glyphosate + 2,4D; 3 acetochlor + paraquat; 4 acetochlor + paraquat + 2,4D; 5 atrazine + glyphosate; 6 atrazine + glyphosate + 2,4D; 7 atrazine + paraquat; 8 atrazine + óleo vegetal; 9 testemunha não tratada. Os tratamentos da sub parcela, em número de dois, foram constituidos pelas modalidades de aplicação dos herbicidas na cobertura vegetal: 1 aplicação com a cobertura "em pé"; 2 aplicação com a cobertura "rolada". A cobertura vegetal de inverno era formada pela consorciação de aveia-preta + ervilhaca comum. Os resultados mostraram que o controle de Brachiaria plantaginea, Euphorbia heterophylla e Bidens pilosa foi melhor efetuado com os tratamentos onde entrou o atrazine. De maneira geral, o controle obtido na modalidade "em pé," foi melhor do que na modalidade "rolada," principalmente nos tratamentos com acetochlor. A análise cromatográfica de resíduos feita em amostras de solo retiradas do experimento antes e após uma chuva de 41mm ocorrida 24 horas após a aplicação dos tratamentos, mostrou que menos de 6 % do acetochlor aplicado foi detectado no solo, em ambas as modalidades de aplicação. Quanto ao atrazine, no entanto, mais de 78 % do total aplicado foi detectado no solo após a chuva na modalidade

  11. Generalized bootstrap for estimating equations

    OpenAIRE

    Chatterjee, Snigdhansu; Bose, Arup

    2005-01-01

    We introduce a generalized bootstrap technique for estimators obtained by solving estimating equations. Some special cases of this generalized bootstrap are the classical bootstrap of Efron, the delete-d jackknife and variations of the Bayesian bootstrap. The use of the proposed technique is discussed in some examples. Distributional consistency of the method is established and an asymptotic representation of the resampling variance estimator is obtained.

  12. Seletividade de herbicidas aplicados em pós-emergência sobre capim-colonião e efeito na qualidade das sementes: effects on seed germination Selectivity of herbicides applied in post-emergence on grass forage

    Directory of Open Access Journals (Sweden)

    L.R.C. Trigueiro

    2007-01-01

    Full Text Available Este estudo foi conduzido para avaliar a seletividade de herbicidas aplicados em pós-emergência sobre plantas de Panicum maximum, cultivares Tanzânia e Mombaça, e os seus efeitos na qualidade das sementes. Os tratamentos testados (em g ha-1 foram: diclofopmethyl (284, ametryne (1.250, propanil (3.600, chlorimuron-ethyl (15, nicosulfuron (50, bentazon (720 e atrazine (3.000, além de uma testemunha sem aplicação de herbicidas. Foram instalados dois experimentos a campo, um para cada cultivar, no delineamento em blocos casualizados com quatro repetições, e um em laboratório, no delineamento inteiramente casualizado, com 16 repetições. O nicosulfuron foi o herbicida que mais causou injúrias visuais e redução de massa seca de plantas em ambos os cultivares. No cultivar Mombaça, todos os herbicidas reduziram a produção de sementes, mas não afetaram a germinação. Para o cultivar Tanzânia, todos os herbicidas foram seletivos, não afetando a produção e a qualidade fisiológica.This study aimed to evaluate the selectivity of some herbicides applied in post-emergence on Panicum maximum cv. Tanzânia and Mombaça and their effect on seed quality. The treatments tested in g ha-1 were: diclofop-methyl at 284, ametryn at 1.250, propanyl at 3.600, chlorimuron-ethyl at 15, nicosulfuron at 50, bentazon at 720 and atrazine at 3.000, and a control plot without herbicide application. Two field trials, one to each cultivar, were carried out in a randomized complete block design, with 4 replications and one laboratory trial was carried out in a randomized complete design, with 16 replications. Nicosulfuron showed the highest levels of visual damage and largest plant dry matter reduction in both cultivars. All the herbicides showed seed production decrease in Mombaca but did not affect seed germination. All the herbicides were selective to cultivar Tanzania, with no damages to plant production and physiological quality.

  13. The bootstrap and Bayesian bootstrap method in assessing bioequivalence

    International Nuclear Information System (INIS)

    Parametric method for assessing individual bioequivalence (IBE) may concentrate on the hypothesis that the PK responses are normal. Nonparametric method for evaluating IBE would be bootstrap method. In 2001, the United States Food and Drug Administration (FDA) proposed a draft guidance. The purpose of this article is to evaluate the IBE between test drug and reference drug by bootstrap and Bayesian bootstrap method. We study the power of bootstrap test procedures and the parametric test procedures in FDA (2001). We find that the Bayesian bootstrap method is the most excellent.

  14. O modelo transteorético aplicado ao consumo de frutas e hortaliças em adolescentes The transtheoretical model applied for fruit and vegetable consumption among adolescents

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Fontes de Oliveira

    2006-02-01

    Full Text Available OBJETIVO: Identificar a relação entre dois constructos do Modelo Transteorético - estágios e processos de mudança - quanto ao consumo de frutas e de hortaliças por adolescentes. MÉTODOS: Em desenho transversal, foi aplicado um questionário a 61 adolescentes, verificando que o uso do processo autoliberação se distinguiu significativamente (pOBJECTIVE: The purpose of this study was to identify the relationship between two constructs of the Transtheoretical Model - stages and processes of change - related to the consumption of fruits and vegetables by adolescents. METHODS: In a cross-sectional study, 61 adolescents were surveyed. The self-liberation process was significantly distinguished (p<0.05 in all stages of change in the consumption of fruits and vegetables. RESULTS: The social support process presented significant differences (p<0.05 between the precontemplation/ contemplation and preparation stages of change only in fruit consumption. CONCLUSION: With respect to the use of the self-reassessment process, significant differences were found (p<0.05 between precontemplation/contemplation and preparation stages in vegetable consumption. Some specific processes of change were used by adolescents when moving through the stages of change. Interventions using these processes should be done to allow advances in the stages of change in the consumption of fruits and vegetables.

  15. Cloreto de mepiquat, thidiazuron e ethephon aplicados no algodoeiro em Ponta Porã, MS Mepiquat chloride, thidiazuron and ethephon applied on cotton in Ponta Porã, MS, Brazil

    Directory of Open Access Journals (Sweden)

    Fernando Mendes Lamas

    1999-10-01

    Full Text Available O objetivo do presente estudo foi avaliar os efeitos de diferentes dosagens de cloreto de mepiquat, thidiazuron e ethephon, aplicadas parceladamente no algodoeiro (Gossypium hirsutum L. na Fazenda Itamarati, Ponta Porã, MS. As dosagens de cloreto de mepiquat foram: (0; 12,5 + 12,5 + 25,0 = 50; 25 + 25 + 25 = 75; 0 + 50 + 50 = 100; 12,5 + 62,5 + 50 = 125 g ha-1, com aplicações efetuadas aos 34, 47 e 62 dias após a emergência (DAE em 1993/94, e aos 42, 60 e 73 DAE, em 1994/95, enquanto o thidiazuron foi aplicado quando 70% dos capulhos estavam abertos, nas dosagens de 0, 45, 60 e 75 g ha-1; já o ethephon foi aplicado sete dias após o thidiazuron, quando já se observava desfolha de 85%, nas dosagens de 0, 960 e 1.440 g ha-1. O delineamento experimental utilizado foi o de blocos casualizados em faixa, com subparcelas subdivididas e quatro repetições. O cloreto de mepiquat proporcionou redução do número de frutos verdes, aumento do peso de 100 sementes e do peso médio de um capulho; a percentagem de desfolha aumentou com as dosagens de thidiazuron e ethephon; constatou-se que a interação cloreto de mepiquat x thidiazuron x ethephon foi significativa para percentagem de abertura de capulhos e produção de algodão em caroço.The objective of this study was to evaluate the effect of doses of mepiquat chloride, thidiazuron and ethephon on cotton (Gossypium hirsutum L., applied in parcels, and were surveyed in Itamarati Farm at Ponta Porã county. The mepiquat chloride doses were: (0.0; 12.5 + 12.5 + 25.0 = 50.0; 25.0 + 25.0 + 25.0 = 75.0; 0.0 + 50.0 + 50.0 = 100.0; 12.5 + 62.5 + 50.0 = 125.0 g ha-1. The applications were made at 34, 47 and 63 days after emergence(DAE in 1993/94 and at 42, 60 and 73 DAE in 1994/95. Thidiazuron was applied when 70% of bolls were opened at the doses 0.0, 45.0, 60.0 and 75.0 g ha-1. Ethephon was applied seven days after thidiazuron, when 85% defoliation was observed, in the doses of 0.0, 960.0 and 1,440.0 g

  16. Eficiência do 2,4-D aplicado isoladamente e em mistura com glyphosate no controle da trapoeraba Efficacy of 2,4-D applied alone or in mixture with glyphosate in the control of dayflower

    Directory of Open Access Journals (Sweden)

    I.C. Santos

    2002-08-01

    Full Text Available A trapoeraba (gênero Commelina é planta daninha-problema em cafezais devido à sua capacidade de sobreviver nas mais diversas condições e tolerância ao herbicida glyphosate. O objetivo deste trabalho foi avaliar a eficiência do herbicida 2,4-D, em doses crescentes, aplicado isoladamente ou em mistura com o glyphosate, no controle de Commelina benghalensis e Commelina diffusa. Para isso, foi conduzido um experimento para cada espécie, em vasos, em casa de vegetação, no delineamento inteiramente casualizado, com cinco repetições. Foram comparados dez tratamentos, que consistiram da combinação de cinco doses de 2,4-D (0; 167,5; 335; 670; e 1.005 g ha-1 e duas doses de glyphosate (0 e 720 g ha¹. Avaliou-se a eficácia dos tratamentos pela porcentagem de controle, avaliada em cinco épocas, em relação à testemunha. Em C. benghalensis, 2,4-D proporcionou controle excelente (>91% aos 33 DAT (dias após tratamento a partir de 167,5 g ha-1 na presença de glyphosate e a partir de 335 g ha-1 na ausência de glyphosate. Em C. diffusa, 2,4-D proporcionou controle excelente aos 33 DAT a partir de 670 g ha-1, tanto na presença quanto na ausência de glyphosate. No entanto, somente a mistura de 2,4-D + glyphosate a 1.005 + 720 g ha-1 provocou 100% de controle desta espécie, verificando-se rebrota das plantas nos outros tratamentos. Nas condições dos experimentos, C. benghalensis mostrou-se mais suscetível que C. diffusa ao herbicida 2,4-D aplicado isoladamente ou em mistura com o glyphosate. Portanto, a identificação da espécie de trapoeraba presente na área a ser tratada e o conhecimento de sua biologia auxiliam na escolha do melhor produto e da dose ideal a ser aplicada, ou mesmo na escolha da mistura adequada, garantindo menor custo e melhor controle, com menores riscos para a cultura e o meio ambiente.The dayflower (genus Commelina is a problem weed in coffee plantations due to its capacity to survive in diversified conditions and

  17. Tolerância inicial de plantas de pinhão-manso a herbicidas aplicados em pré e pós-emergência Initial tolerance of physic nut plants to pre and post-emergence herbicide application

    OpenAIRE

    E.A.L Erasmo; N.V. Costa; M.A. Terra; R. R. Fidelis

    2009-01-01

    O presente trabalho teve por objetivo avaliar a tolerância inicial de plantas de pinhão-manso a herbicidas pré e pós-emergentes, aplicados isolados e em misturas. Foram realizados dois experimentos em condições de campo, sendo um com herbicidas pré-emergentes e outro com herbicidas pós-emergentes. Os tratamentos com os herbicidas pré-emergentes utilizados foram: atrazine (3.000 g ha-1), diuron (2.000 g ha-1), oxyfluorfen (720 g ha-1), trifluralin (890 g ha-1), pendimethalin (1.250 g ha-1), is...

  18. Deposição de glyphosate aplicado para controle de plantas daninhas em soja transgênica Glyphosate deposition for weed control in transgenic soybean

    Directory of Open Access Journals (Sweden)

    D.L.P. Gazziero

    2006-01-01

    Full Text Available Inúmeros fatores estão envolvidos na tecnologia de aplicação de um herbicida, sendo a deposição correta fundamental para que o produto possa expressar sua eficiência. Com o objetivo de avaliar a deposição de uma solução traçante constituída de glyphosate Roundup Ready (0,96 kg e.a. ha-1 + corante FDC-1 (1.500 ppm, foi conduzido um experimento em área semeada com soja transgênica e infestada com amendoim-bravo (Euphorbia heterophylla, localizada em Londrina-PR. As aplicações foram efetuadas em diferentes estádios de desenvolvimento da cultura, correspondendo a 17, 24, 31, 38 e 45 dias após a emergência da soja. Os alvos, plantas de soja, amendoim-bravo e placas na superfície do solo (linha e entrelinha, foram coletados após pulverização, e a solução traçante foi nestes depositada, posteriormente recuperada através de lavagem com agitação em água destilada. As amostras das soluções recuperadas foram submetidas à análise, utilizando-se procedimentos espectrofotométricos, e os resultados de absorbância convertidos para concentração em µL cm-2 e µL por planta. As freqüências acumuladas dos dados originais de depósito foram adequadamente ajustadas segundo modelo de Gompertz, apresentando elevada precisão (R² > 0,95. Os resultados indicaram que o depósito da calda de pulverização nas plantas de soja e amendoim-bravo reduziu progressivamente com o desenvolvimento da cultura e infestação, sugerindo que a maior garantia de eficiência de controle pode ser conseguida com aplicações precoces.Several factors are involved in herbicide application technology, with correct deposition being essential to ensure product efficacy. To evaluate the deposition of a glyphosate tracer solution (RR with an FDC-1 dye, an experiment was carried out in a transgenic soybean cultivated area, infested with wild poinsettia (Euphorbia heterophylla. Applications were carried out at different crop development stages

  19. The conformal bootstrap

    Science.gov (United States)

    Poland, David; Simmons-Duffin, David

    2016-06-01

    The conformal bootstrap was proposed in the 1970s as a strategy for calculating the properties of second-order phase transitions. After spectacular success elucidating two-dimensional systems, little progress was made on systems in higher dimensions until a recent renaissance beginning in 2008. We report on some of the main results and ideas from this renaissance, focusing on new determinations of critical exponents and correlation functions in the three-dimensional Ising and O(N) models.

  20. Jogo da Minoria: um modelo baseado em agentes aplicado ao mercado financeiro Minority Game: an agent-based model applied to financial market

    Directory of Open Access Journals (Sweden)

    Antonio Fernando Crepaldi

    2012-12-01

    Full Text Available Nos últimos anos houve uma contribuição significativa dos físicos para a construção de um tipo de modelo baseado em agentes que busca reproduzir, em simulação computacional, o comportamento do mercado financeiro. Esse modelo, chamado Jogo da Minoria consiste de um grupo de agentes que vão ao mercado comprar ou vender ativos. Eles tomam decisões com base em estratégias e, por meio delas, os agentes estabelecem um intrincado jogo de competição e coordenação pela distribuição da riqueza. O modelo tem demonstrado resultados bastante ricos e surpreendentes, tanto na dinâmica do sistema como na capacidade de reproduzir características estatísticas e comportamentais do mercado financeiro. Neste artigo, são apresentadas a estrutura e a dinâmica do Jogo da Minoria, bem como as contribuições recentes relacionadas ao Jogo da Minoria denominado de Grande Canônico, que é um modelo mais bem ajustado às características do mercado financeiro e reproduz as regularidades estatísticas do preço dos ativos chamadas fatos estilizados.Over the past ten years physicists have made a significant contribution to the building of an agent-based model to reproduce the behavior of financial markets using computer simulation. This model, called the Minority Game, consists of a group of agents that buy or sell assets. They make decisions based on strategies, and through them the agents establish an intricate game of competition and coordination resulting in the distribution of wealth. The model has shown outstanding surprising results concerning both the dynamics of the system and the ability to reproduce statistical and behavior characteristics of the financial market. In this study, the structure and dynamics of the Minority Game and the recent contributions related to the Grand Canonical Minority game, a model which is better adapted to the characteristics of the financial market and reproduce the statistical regularities of asset prices (called

  1. Sistema computacional para dosimetria de nêutrons e fótons baseado em métodos estocásticos aplicado a radioterapia e radiologia

    Directory of Open Access Journals (Sweden)

    Bruno Machado Trindade

    2011-04-01

    Full Text Available OBJETIVO: Este artigo mostra um procedimento de conversão de imagens de tomografia computadorizada ou de ressonância magnética em modelo de voxels tridimensional para fim de dosimetria. Este modelo é uma representação personalizada do paciente que pode ser usado na simulação, via código MCNP (Monte Carlo N-Particle, de transporte de partículas nucleares, reproduzindo o processo estocástico de interação de partículas nucleares com os tecidos humanos. MATERIAIS E MÉTODOS: O sistema computacional desenvolvido, denominado SISCODES, é uma ferramenta para planejamento computacional tridimensional de tratamentos radioterápicos ou procedimentos radiológicos. Partindo de imagens tomográficas do paciente, o plano de tratamento é modelado e simulado. São então mostradas as doses absorvidas, por meio de curvas de isodoses superpostas ao modelo. O SISCODES acopla o modelo tridimensional ao código MCNP5, que simula o protocolo de exposição à radiação ionizante. RESULTADOS: O SISCODES vem sendo utilizado no grupo de pesquisa NRI/CNPq na criação de modelos de voxels antropomórficos e antropométricos que são acoplados ao código MCNP para modelar braquiterapias e teleterapias aplicadas a tumores em pulmões, pelve, coluna, cabeça, pescoço, e outros. Os módulos atualmente desenvolvidos no SISCODES são apresentados junto com casos exemplos de planejamento radioterápico. CONCLUSÃO: O SISCODES provê de maneira rápida a criação de modelos de voxels personalizados de qualquer paciente que podem ser usados em simulações por códigos estocásticos tipo MCNP. A combinação da simulação via MCNP com um modelo personalizado do paciente traz grandes melhorias na dosimetria de tratamentos radioterápicos.

  2. Bootstrap and Wild Bootstrap for High Dimensional Linear Models

    OpenAIRE

    Mammen, Enno

    1993-01-01

    In this paper two bootstrap procedures are considered for the estimation of the distribution of linear contrasts and of F-test statistics in high dimensional linear models. An asymptotic approach will be chosen where the dimension p of the model may increase for sample size $n\\rightarrow\\infty$. The range of validity will be compared for the normal approximation and for the bootstrap procedures. Furthermore, it will be argued that the rates of convergence are different for the bootstrap proce...

  3. Rendimento de feijão e de grão-de-bico em função de fosfato solúvel aplicado em covas ou na linha de semeadura

    Directory of Open Access Journals (Sweden)

    M. Voss

    1998-03-01

    Full Text Available Entre os macronutrientes, o fósforo é o que com maior freqüência proporciona aumento na produtividade das culturas. Tem-se demonstrado que a obtenção de nitrogênio por algumas das simbioses rizóbio-leguminosas exige teores maiores de fósforo do que a planta adubada com nitrogênio. Visando aumentar a eficiência no aproveitamento de fósforo no solo sem incrementar a dose de adubação, testaram-se modos de localização de adubo com fosfato solúvel para as culturas de feijão e de grão-de-bico. O feijão, em ensaio instalado em Jaguapitã (PR, foi semeado, em outubro de 1986, em um Latossolo Vermelho-Escuro com 113 g kg-1 de argila e 2,2 mg dm-3 de P. O adubo fosfatado foi distribuído a 7 cm, e as sementes a 3 cm de profundidade, ambos no sulco de semeadura. Comparou-se a adubação no sulco com a adubação em covas, em doses de 50 e de 100 kg ha-1 de P2O5, como superfosfato triplo (SFT. Incluiu-se um tratamento extra com 25 kg ha-1 de P2O5 em covas, além de testemunha sem adubação fosfatada. O feijão foi semeado em covas. O ensaio com grão-de-bico foi instalado em Londrina (PR, em junho de 1987, em um Latossolo Roxo com 760 g kg-1 de argila e 3,6 mg dm-3 de P. A adubação foi feita a 7 cm de profundidade, e a semeadura a 3 cm de profundidade. Nesse ensaio, foram testados, nas parcelas, os tratamentos: testemunha sem rizóbio, inoculação com rizóbio e sem inoculação + 30 kg ha-1 de N e, nas subparcelas, a adubação fosfatada em linha ou em covas. O grão-de-bico foi semeado em linha. Foram avaliados os teores de N, P, Zn e Mn nas folhas de feijão, bem como a produtividade e a nodulação de feijão e de grão-de-bico. Não houve nodulação em feijão e a tendência para maior nodulação em grão-de-bico, quando a adubação foi aplicada em covas, não foi significativa. Houve aumento de cerca de 40% no rendimento do feijão e de 3l% no de grão-de-bico pela adubação em covas, em relação à adubação em linha. Em

  4. Convex and Monotonic Bootstrapped Kriging

    OpenAIRE

    Kleijnen, Jack P.C.; Mehdad, E.; Beers, W.C.M. van

    2012-01-01

    Abstract: Distribution-free bootstrapping of the replicated responses of a given discreteevent simulation model gives bootstrapped Kriging (Gaussian process) metamodels; we require these metamodels to be either convex or monotonic. To illustrate monotonic Kriging, we use an M/M/1 queueing simulation with as output either the mean or the 90% quantile of the transient-state waiting times, and as input the traffic rate. In this example, monotonic bootstrapped Kriging enables better sensitivity a...

  5. Poor (wo)man's bootstrap

    OpenAIRE

    Bo E. Honoré; Hu, Luojia

    2015-01-01

    The bootstrap is a convenient tool for calculating standard errors of the parameters of complicated econometric models. Unfortunately, the fact that these models are complicated often makes the bootstrap extremely slow or even practically infeasible. This paper proposes an alternative to the bootstrap that relies only on the estimation of one-dimensional parameters. The paper contains no new difficult math. But we believe that it can be useful.

  6. Tannery and coal mining waste disposal on soil Resíduos do processamento de peles e de carvão mineral aplicados em solo

    Directory of Open Access Journals (Sweden)

    Claudio Henrique Kray

    2008-12-01

    Full Text Available Tannery residues and coal mine waste are heavily polluting sources in Brazil, mainly in the Southern States of Rio Grande do Sul and Santa Catarina. In order to study the effects of residues of chrome leather tanning (sludge and leather shavings and coal waste on soybean and maize crops, a field experiment is in progress since 1996, at the Federal University of Rio Grande do Sul Experimental Station, county of Eldorado do Sul, Brazil. The residues were applied twice (growing seasons 1996/97 and 1999/00. The amounts of tannery residues were applied according to their neutralizing value, at rates of up to 86.8 t ha-1, supplying from 671 to 1.342 kg ha-1 Cr(III; coal waste was applied at a total rate of 164 t ha-1. Crop yield and dry matter production were evaluated, as well as the nutrients (N, P, K, Ca, Mg, Cu and Zn and Cr contents. Crop yields with tannery sludge application were similar to those obtained with N and lime supplied with mineral amendments. Plant Cr absorption did not increase significantly with the residue application. Tannery sludge can be used also to neutralize the high acidity developed in the soil by coal mine waste.Os resíduos gerados na exploração de carvão mineral e no processamento de peles são produtos potencialmente poluentes em várias regiões do Brasil, principalmente nos Estados do Rio Grande do Sul e de Santa Catarina. O presente trabalho foi conduzido a campo com o objetivo de avaliar o efeito da aplicação e da reaplicação de resíduos carbonífero e de curtume ao Cr sobre as plantas de milho e de soja cultivadas em um Argissolo Vermelho distrófico típico, na Estação Experimental da UFRGS, localizada no município de Eldorado do Sul (RS. A primeira aplicação dos resíduos foi feita no ano agrícola de 1996/97 e a reaplicação no ano agrícola de 1999/2000. As doses de resíduos de curtume variaram conforme o pH do solo e o poder de neutralização do resíduo, tendo sido adicionadas quantidades

  7. Detrending bootstrap unit root tests

    OpenAIRE

    Smeekes, S.

    2009-01-01

    The role of detrending in bootstrap unit root tests is investigated. When bootstrapping, detrending must not only be done for the construction of the test statistic, but also in the first step of the bootstrap algorithm. It is argued that the two points should be treated separately. Asymptotic validity of sieve bootstrap ADF unit root tests is shown for test statistics based on full sample and recursive OLS and GLS detrending. It is also shown that the detrending method in the first step of t...

  8. Efficacy of herbicides applied to Digitaria horizontalis plants under different water conditions Eficácia de herbicidas aplicados em plantas de Digitaria horizontalis Submetidas a diferentes condições hídricas

    Directory of Open Access Journals (Sweden)

    M.R.R. Pereira

    2012-03-01

    Full Text Available This project aimed to relate the control efficiency of ACCase inhibiting herbicides applied post-emergence to Digitaria horizontalis plants under different soil water contents. The experiments were conducted in a greenhouse, with the application of three different herbicides (fluazifop-p-butyl, haloxyfop-methyl, and sethoxydim + mineral oil Assist. The experimental design used for each herbicide was completely randomized, with four replications, consisting of a 3 x 4 factorial, with the combination of water management strategies (-0.03, -0.07 and -1.5 MPa and four doses of these products (100%, 50%, 25%, and 0% of the recommended dose. Herbicide application was made at two vegetative stages, 4-6 leaves and 2-3 tillers. The visual phytotoxicity evaluations were performed at 14 days after application and the plant dry weight at the end of the study was evaluated. The control efficiency was not affected by water management strategies when applied to the recommended dose of the herbicides in early stages of plant development (4-6 leaf stage. In late applications (2-3 tiller stage the plants held under drought stress showed less phytotoxicity.Este projeto objetivou relacionar a eficiência de controle de herbicidas inibidores da ACCase aplicados em pós-emergência em plantas de Digitaria horizontalis submetidas a diferentes teores de água no solo. Os experimentos foram conduzidos em casa de vegetação, com a aplicação de três diferentes herbicidas (fluazifop-p-butil, haloxyfop-methyl e sethoxydim + óleo mineral Assist. O delineamento experimental utilizado para cada herbicida foi inteiramente casualizado, com quatro repetições, constituído de um fatorial 3 x 4, sendo a combinação de três manejos hídricos (-0,03, 0,07 e -1,5 MPa e quatro doses desses produtos (100, 50, 25 e 0% da dose recomendada. A aplicação dos herbicidas foi feita em dois estádios vegetativos: 4-6 folhas e 2-3 perfilhos. As avaliações visuais de fitotoxicidade

  9. Absorção e redistribuição do nitrogênio aplicado via foliar em videiras jovens Uptake and redistribution of nitrogen in foliar application in young grapevines

    Directory of Open Access Journals (Sweden)

    Gustavo Brunetto

    2005-04-01

    Full Text Available A aplicação de nitrogênio via foliar antes da senescência das folhas da videira pode ser uma estratégia para aumentar as reservas deste nutriente nas partes perenes, uma vez que as mesmas são disponibilizadas no início do crescimento vegetativo dos órgãos anuais. O objetivo deste trabalho foi de estimar a absorção e a redistribuição do N adicionado via foliar em videiras jovens. O experimento foi instalado em casa de vegetação na EMBRAPA-Uva e Vinho, no município de Bento Gonçalves (RS. Foram utilizadas as variedades Chardonnay e Riesling Itálico com porta-enxerto 101-14 Mgt. Foi cultivada uma planta por vaso contendo 10kg de solo Neossolo Litólico. A aplicação do N via foliar foi parcelada em três vezes, durante três dias sucessivos. Foram aplicados 84,84mg N planta-1 na forma de (15NH42SO4 . As plantas foram colhidas em sete épocas diferentes. Após a colheita, as plantas foram fracionadas em folhas, enxerto, porta-enxerto, raízes grossas (>2mm e raízes finas (The foliar application of nitrogen before the leaves senescence may be a strategy to increase the nutrient reserves in the perennial parts, being available in the beginning of the vegetative growth of the annual parts. The objective of this work was to estimate the uptake and redistribution of N applied by foliar way in young grapevines. The experiment was carried out in a greenhouse at EMBRAPA-Grape and Wine, Bento Gonçalves Southern Brazil. The cultivars used were Chardonnay and Riesling Italic grafted on rootstock 101-14 Mgt. It was cultivated one plant by vase with 10kg of soil Udorthent. The foliar application of N was parceled in three times during three successive days. It was applied 84,84mg N plant-1 using (15NH42SO4 . The plants were collected in seven times, during vegetative growth. The plants were fractionated in leaves, graft, carry-graft, thick roots (>2mm and fine roots (<2mm, oven-dried, weighted, and analyzed N-total and 15N contents. The

  10. Seletividade de herbicidas aplicados em pré-emergência da cultura da cana-de-açúcar (RB 867515 tratada com nematicidas Selectivity of herbicides applied on pre-emergence of nematicide-treated sugarcane crop (RB 867515

    Directory of Open Access Journals (Sweden)

    J.F. Barela

    2006-06-01

    Full Text Available A aplicação simultânea de duas ou mais classes de defensivos sobre uma cultura agrícola pode provocar toxicidade às plantas. Assim, conduziu-se um experimento com o objetivo de avaliar a seletividade de herbicidas à cultura da cana-de-açúcar (RB 867515, quando aplicados em condição de pré-emergência, em áreas previamente tratadas com nematicidas no sulco de plantio. O experimento foi desenvolvido em área comercial de produção de cana-de-açúcar, no município de Piracicaba - SP, entre abril de 2003 e julho de 2004. Os tratamentos resultaram da combinação entre nove fatores herbicidas e quatro fatores nematicidas. Os herbicidas usados no experimento foram: sulfentrazone, tebuthiuron, metribuzin, ametrina, diuron, clomazone, pendimethalin e diuron + hexazinone, além de uma testemunha capinada. Os nematicidas utilizados foram: carbofuran, terbufós, aldicarb e uma testemunha sem nematicida. Avaliou-se a fitotoxicidade das diferentes combinações aos 15, 30, 60 e 90 dias após a brotação, o rendimento (t ha-1 e os parâmetros tecnológicos qualitativos. Observou-se que a seletividade inicial dos herbicidas foi prejudicada em função da interação das diferentes classes de defensivos utilizadas. Os sintomas de fitotoxicidade foram agudos, e os casos mais evidentes se originaram da associação dos nematicidas com clomazone, pendimethalin e tebuthiuron. Contudo, os danos fitotóxicos não se refletiram em perdas significativas de rendimento ou de qualidade de colmos, fato esse que pode ter sido influenciado pela capacidade de recuperação de injúrias apresentada pela variedade RB 867515, pela ocorrência de altas infestações de nematóides ou pela elevada variabilidade experimental.Simultaneous applications of two or more classes of herbicides on a crop may promote ,totoxicity in the plants. Therefore, an experiment was conducted to evaluate herbicide selectivity in sugarcane, when applied under pre-emergence condition, in

  11. Towards Bootstrapping QED$_3$

    CERN Document Server

    Chester, Shai M

    2016-01-01

    We initiate the conformal bootstrap study of Quantum Electrodynamics in $2+1$ space-time dimensions (QED$_{3}$) with $N$ flavors of charged fermions by focusing on the 4-point function of four monopole operators with the lowest unit of topological charge. We obtain upper bounds on the scaling dimension of the doubly-charged monopole operator, with and without assuming other gaps in the operator spectrum. Intriguingly, we find a (gap-dependent) kink in these bounds that comes reasonably close to the large $N$ extrapolation of the scaling dimensions of the singly-charged and doubly-charged monopole operators down to $N=4$ and $N=6$.

  12. Bootstrapping 3D fermions

    Science.gov (United States)

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-01

    We study the conformal bootstrap for a 4-point function of fermions in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  13. Bootstrapping structured page segmentation

    Science.gov (United States)

    Ma, Huanfeng; Doermann, David S.

    2003-01-01

    In this paper, we present an approach to the bootstrap learning of a page segmentation model. The idea evolves from attempts to segment dictionaries that often have a consistent page structure, and is extended to the segmentation of more general structured documents. In cases of highly regular structure, the layout can be learned from examples of only a few pages. The system is first trained using a small number of samples, and a larger test set is processed based on the training result. After making corrections to a selected subset of the test set, these corrected samples are combined with the original training samples to generate bootstrap samples. The newly created samples are used to retrain the system, refine the learned features and resegment the test samples. This procedure is applied iteratively until the learned parameters are stable. Using this approach, we do not need to initially provide a large set of training samples. We have applied this segmentation to many structured documents such as dictionaries, phone books, spoken language transcripts, and obtained satisfying segmentation performance.

  14. Graph bootstrap percolation

    CERN Document Server

    Balogh, József; Morris, Robert

    2011-01-01

    Graph bootstrap percolation is a deterministic cellular automaton which was introduced by Bollob\\'as in 1968, and is defined as follows. Given a graph $H$, and a set $G \\subset E(K_n)$ of initially `infected' edges, we infect, at each time step, a new edge $e$ if there is a copy of $H$ in $K_n$ such that $e$ is the only not-yet infected edge of $H$. We say that $G$ percolates in the $H$-bootstrap process if eventually every edge of $K_n$ is infected. The extremal questions for this model, when $H$ is the complete graph $K_r$, were solved (independently) by Alon, Kalai and Frankl almost thirty years ago. In this paper we study the random questions, and determine the critical probability $p_c(n,K_r)$ for the $K_r$-process up to a poly-logarithmic factor. In the case $r = 4$ we prove a stronger result, and determine the threshold for $p_c(n,K_4)$.

  15. Tolerância de mudas de café a herbicidas aplicados em pós-emergência Tolerance of coffee plants to post emergence herbicide application

    Directory of Open Access Journals (Sweden)

    C.P. Ronchi

    2003-12-01

    Full Text Available Este trabalho teve como objetivo avaliar a tolerância de mudas de café à aplicação de herbicidas em pós-emergência. Flumiozaxin, sulfentrazone, flazasulfuron, clethodim, fluazifop-p-butil, imazamox, bentazon, fomesafen, lactofen, oxyfluorfen, chlorimuron-ethil, metribuzin e também as misturas de fluazifop-p-butil + fomesafen e de nicosulfuron + atrazine foram aplicados diretamente sobre o topo das plantas, 15 dias após o transplantio das mudas de café para os vasos (3,0 L. Foram feitas avaliações visuais de toxicidade dos herbicidas às plantas de café e, também, avaliações da altura, do diâmetro e da massa seca da parte aérea e das raízes dessas plantas. O metribuzin e a mistura em tanque de nicosulfuron + atrazine causaram morte das plantas de café, enquanto imazamox, sulfentrazone, oxyfluorfen e lactofen causaram severa toxicidade (49 a 64%. Dentre os herbicidas avaliados, aqueles que mais reduziram a altura das plantas, em relação à testemunha, foram imazamox e sulfentrazone (62 e 68%, respectivamente. O acúmulo de matéria seca, tanto da parte aérea como do sistema radicular, foi no máximo 67% daquele apresentado pela testemunha para sulfentrazone, flazasulfuron, imazamox, lactofen e oxyfluorfen. O maior potencial para uso em pós-emergência, sobre o topo das plantas, foi obtido com fluazifop-p-butil, clethodim, fomesafen, chlorimuron-ethil, flumioxazin e fluazifop-p-butil + fomesafen, uma vez que causaram apenas leves injúrias e não afetaram o acúmulo de matéria seca do cafeeiro.This work was conducted to evaluate the tolerance of coffee plant seedlings to post emergence herbicide application. Flumiozaxin, sulfentrazone, flazasulfuron, clethodim, fluazifop-p-butil, imazamox, bentazon, fomesafen, lactofen, oxyfluorfen, chlorimuron-ethil, metribuzin and also the mixtures of fluazifop-p-butil + fomesafen and of nicosulfuron + atrazine were sprayed directly on top of the plants, 15 days after coffee seedling

  16. Eficácia de herbicidas graminicidas aplicados em pré-emergência no sistema de semeadura direta do milho Efficacy of no-till applied graminicide herbicides in corn

    Directory of Open Access Journals (Sweden)

    Vitor Spader

    2000-08-01

    Full Text Available A produtividade do milho tem sido diminuida pela interferência com plantas daninhas durante o período crítico de prevenção da interferência (PCPI. Foi desenvolvido um experimento na EEA/UFRGS em Eldorado do Sul, RS, na safra de 1998/99, com objetivo de avaliar a eficácia de herbicidas graminicidas, aplicados em pré-emergência, no controle de Brachiaria plantaginea (BRAPL no sistema de semeadura direta do milho. O híbrido utilizado foi AG 5011 numa população de 70.000 plantas/ha. Os tratamentos foram 5 herbicidas com 2 doses, além de testemunha capinada e testemunha sem controle. Os herbicidas com as respectivas doses (kg i. a. ha-1 foram, acetochlor (3,0 e 4,0, metolachlor (2,5 e 3,0, trifluralin (3,0 e 4,0, pendimethalin (2,5 e 3,0 e isoxaflutole (0,06 e 0,07 g i. a. ha-1. O delineamento experimental foi o de blocos casualizados com 4 repetições. Avaliou-se o nível de controle, população e produção de matéria seca das plantas de BRAPL e rendimento de grãos do milho. A infestação de 117 plantas/m2 de BRAPL reduziu em 80 % o rendimento de grãos do milho. Quanto maior a produção de matéria seca da BRAPL, durante o PCPI, mais intenso foi seu efeito sobre o rendimento da cultura. Os herbicidas reduziram a infestação e aumentaram o rendimento do milho em relação à testemunha sem controle. Os melhores controles de BRAPL foram obtidos com isoxaflutole e, de modo geral, com a dose mais elevada. O rendimento do milho foi negativamente correlacionado com a população e produção de matéria seca das plantas daninhas, indicando que redução no número de plantas de BRAPL, aumentam o rendimento do milho.The productivity of corn crop is reduced by the interference of weeds. An experiment was conducted at Eldorado do Sul, RS/Brazil, in 1998-1999, to evaluate the efficacy of grass herbicides applied during preemergence on the control of Brachiaria plantaginea (BRAPL in no-tilled corn.The corn hybrid was AG 5011 planted at 70

  17. Applications of the Fast Double Bootstrap

    OpenAIRE

    MacKinnon, James G.

    2006-01-01

    The fast double bootstrap, or FDB, is a procedure for calculating bootstrap P values that is much more computationally efficient than the double bootstrap itself. In many cases, it can provide more accurate results than ordinary bootstrap tests. For the fast double bootstrap to be valid, the test statistic must be asymptotically independent of the random parts of the bootstrap data generating process. This paper presents simulation evidence on the performance of FDB tests in three cases of in...

  18. Breakdown Point Theory for Implied Probability Bootstrap

    OpenAIRE

    Lorenzo Camponovo; Taisuke Otsu

    2011-01-01

    This paper studies robustness of bootstrap inference methods under moment conditions. In particular, we compare the uniform weight and implied probability bootstraps by analyzing behaviors of the bootstrap quantiles when outliers take arbitrarily large values, and derive the breakdown points for those bootstrap quantiles. The breakdown point properties characterize the situation where the implied probability bootstrap is more robust than the uniform weight bootstrap against outliers. Simulati...

  19. The bootstrap fraction in TFTR

    International Nuclear Information System (INIS)

    The TRANSP plasma analysis code is used to calculate the bootstrap current generated during neutral beam injection and ion cyclotron resonance frequency heating for a wide variety of TFTR discharges. An empirical scaling relation is given for the bootstrap current fraction using the ratio of the peakednesses of the thermal pressure and of the total current density. copyright 1997 American Institute of Physics

  20. On sieve bootstrap prediction intervals.

    OpenAIRE

    Andrés M. Alonso; Peña, Daniel; Romo Urroz, Juan

    2003-01-01

    In this paper we consider a sieve bootstrap method for constructing nonparametric prediction intervals for a general class of linear processes. We show that the sieve bootstrap provides consistent estimators of the conditional distribution of future values given the observed data.

  1. Ultrafast Approximation for Phylogenetic Bootstrap

    NARCIS (Netherlands)

    Bui Quang Minh, [No Value; Nguyen, Thi; von Haeseler, Arndt

    2013-01-01

    Nonparametric bootstrap has been a widely used tool in phylogenetic analysis to assess the clade support of phylogenetic trees. However, with the rapidly growing amount of data, this task remains a computational bottleneck. Recently, approximation methods such as the RAxML rapid bootstrap (RBS) and

  2. Explorations in Statistics: the Bootstrap

    Science.gov (United States)

    Curran-Everett, Douglas

    2009-01-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This fourth installment of Explorations in Statistics explores the bootstrap. The bootstrap gives us an empirical approach to estimate the theoretical variability among possible values of a sample statistic such as the…

  3. Second Thoughts on the Bootstrap

    OpenAIRE

    Efron, Bradley

    2003-01-01

    This brief review article is appearing in the issue of Statistical Science that marks the 25th anniversary of the bootstrap. It concerns some of the theoretical and methodological aspects of the bootstrap and how they might influence future work in statistics.

  4. Seletividade de herbicidas para a cultura de milho (Zea mays aplicados em diferentes estádios fenológicos da cultura Selectivity to corn crop (Zea mays of herbicides applied in different crop phenological stages

    Directory of Open Access Journals (Sweden)

    R.F. López-Ovejero

    2003-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a seletividade de herbicidas aplicados em condições de pré e pós-emergência da cultura de milho, conduzida sob sistema de semeadura direta, sem a presença de plantas daninhas durante todo o ciclo da cultura. O híbrido utilizado foi o Pioneer 3027, e o delineamento experimental adotado foi em blocos casualizados, com 22 tratamentos e três repetições. Os tratamentos herbicidas utilizados (em g i.a. ha-1, com os respectivos estádios fenológicos (número de folhas definitivas = NF no momento da aplicação dos respectivos tratamentos herbicidas, foram: atrazine + metolachlor (1.400 + 2.100 em condições de pré-emergência da cultura; (atrazine + metolachlor + nicosulfuron [(1.000 + 1.500 + 20] com a cultura apresentando NF = 2; atrazine + óleo vegetal (2.400 + 1.800, NF = 2, 4 e 8; atrazine + simazine (1.250 + 1.250, NF = 2, 4 e 8; nicosulfuron (40 - NF = 2, 4 e 8; 20 - NF = 4 e 8 e 52 - NF = 4 e 8; e (atrazine + óleo vegetal + nicosulfuron [(800 + 600 + 20; (800 + 600 + 40 e (800 + 600 + 52, NF = 4 e 8]. Foram feitas avaliações visuais de sintomas de fitotoxicidade provocados pelos herbicidas aos 7, 14 e 21 dias após aplicação, usando a escala proposta pela European Weed Research Council, além dos parâmetros relativos aos componentes de produção da cultura e produtividade final. Os resultados obtidos indicaram que a duração dos estádios fenológicos da cultura não foi afetada pelos herbicidas utilizados e que alguns tratamentos herbicidas, quando aplicados no estádio fenológico 2 (NF = 8 , reduzem o rendimento da cultura, devido à alteração do número de fileiras por espiga, do número de grãos por fileira e da massa de 1.000 grãos de milho, sendo recomendável a aplicação de herbicidas na cultura de milho até o estádio fenológico 1 (NF = 4, para evitar danos à cultura por fitotoxicidade.The objective of this research was to evaluate the selectivity of pre and post

  5. Estrutura fatorial do questionário de morbidade psiquiátrica de adultos aplicado em amostras populacionais de cidades brasileiras The factor structure of the adult psychiatry morbidity questionnaire (QMPA in a community sample of Brazilian cities

    Directory of Open Access Journals (Sweden)

    Sérgio Baxter Andreoli

    1994-08-01

    Full Text Available A análise de componentes principais é uma técnica de estatística multivariada utilizada para examinar a interdependência entre variáveis. A sua principal característica é a capacidade de reduzir dados, e tem sido usada para o desenvolvimento de instrumentos de pesquisas psiquiátricas e na classificação dos transtornos psiquiátricos. Esta técnica foi utilizada para estudar a estrutura fatorial do Questionário de Morbidade Psiquiátrica do Adulto (QMPA. O questionário foi composto de 45 questões de resposta sim/não que identificam sintomas psiquiátricos, uso de serviço e de drogas psicotrópicas. O questionário foi aplicado em 6.470 indivíduos maiores de 15 anos, em amostras representativas da população de três cidades brasileiras (Brasília, São Paulo e Porto Alegre. O estudo teve como objetivo comparar a estrutura fatorial do questionário nas três regiões urbanas brasileiras. Sete fatores foram encontrados que explicam 42,7% da variância total da amostra. O fator 1, Ansiedade/Somatização ("eigenvalue" (EV = 3.812 e variância explicada (VE = 10,9%; O fator 2, Irritabilidade/Depressão (EV = 2.412 e VE = 6,9%; O fator 3, Deficiência Mental (EV= 2.014 e VE = 5,8%; O fator 4, Alcoolismo (EV = 1.903 e VE = 5,4%; O fator 5, Exaltação do Humor (EV = 1.621 e VE = 4,6%; O fator 6, Transtorno de Percepção (EV = 1.599 e VE = 4,6% e o fator 7, Tratamento (EV = 1.592 e VE = 4,5%.O QMPA apresentou estruturas fatoriais semelhantes nas três cidades. Baseados nos achados, são feitas sugestões para que algumas questões sejam modificadas e para a exclusão de outras em uma futura versão do questionário.Principal Components Analysis is a multivariate statistical technique for the purpose of examining the interdependence among variables. The main characteristic of this technique is the ability to reduce data, and it is currently used as an adjunct for the development of psychiatric research tools and the classification of

  6. Modular Bootstrap Revisited

    CERN Document Server

    Collier, Scott; Yin, Xi

    2016-01-01

    We constrain the spectrum of two-dimensional unitary, compact conformal field theories with central charge c > 1 using modular bootstrap. Upper bounds on the gap in the dimension of primary operators of any spin, as well as in the dimension of scalar primaries, are computed numerically as functions of the central charge using semi-definite programming. Our bounds refine those of Hellerman and Friedan-Keller, and are in some cases saturated by known CFTs. In particular, we show that unitary CFTs with c < 8 must admit relevant deformations, and that a nontrivial bound on the gap of scalar primaries exists for c < 25. We also study bounds on the dimension gap in the presence of twist gaps, bounds on the degeneracy of operators, and demonstrate how "extremal spectra" which maximize the degeneracy at the gap can be determined numerically.

  7. Atividade residual de herbicidas aplicados ao solo em relação ao controle de quatro espécies de Amaranthus Residual activity of herbicides applied to the soil in relation to control of four Amaranthus Species

    Directory of Open Access Journals (Sweden)

    M.A. Raimondi

    2010-01-01

    Full Text Available Herbicidas aplicados em pré-emergência normalmente apresentam atividade residual no solo, controlando os primeiros fluxos germinativos das plantas daninhas e prevenindo a matocompetição inicial. O objetivo deste trabalho foi verificar o período de atividade residual proporcionado por doses de herbicidas suficientes para o controle pontual de 95% (C95 das espécies Amaranthus hybridus, A. lividus, A. spinosus e A. viridis, além de avaliar doses recomendadas desses herbicidas. O trabalho foi realizado em casa de vegetação, em solo de textura franco-argiloarenosa (20% de argila e 1,9 de matéria orgânica, e as doses dos herbicidas alachlor, diuron, oxyfluorfen, pendimethalin, prometryne, oxyfluorfen, S-metolachlor, trifluralin 450 e trifluralin 600 foram aplicadas aos 30, 20, 10 e 0 dias antes da semeadura das plantas daninhas. Avaliou-se o controle das plantas daninhas após a permanência dos herbicidas no solo por períodos de 0, 10, 20 e 30 dias depois da aplicação dos tratamentos (DAA. A atividade residual de alachlor e prometryne, na dose C95, não foi suficiente para o controle eficiente (>80% das espécies por períodos de até 30 DAA. Quanto ao alachlor, o emprego da dose recomendada não se refletiu em aumento considerável da atividade residual, exceto em relação a A. viridis. A dose recomendada de prometryne proporcionou controle eficiente das espécies até 30 DAA, exceto de A. hybridus. A dose recomendada de oxyfluorfen controlou eficientemente A. hybridus e A. spinosus até 30 DAA, espécies estas que não haviam sido eficientemente controladas pela dose C95. Trifluralin 450 promoveu controle residual eficiente de 30 DAA somente em relação a A. hybridus. Trifluralin 600 foi eficiente no controle de A. hybridus e A. viridis até os 30 DAA e até 29 e 28 DAA para A. lividus e A. spinosus, respectivamente. Clomazone não promoveu controle eficiente das espécies até 30 DAA, exceto de A. viridis. Diuron, pendimethalin e S

  8. Comparação dos metodos de inventarios florestais sucessivos em relação a amostragem com repetição parcial, aplicados em uma população estratificada

    OpenAIRE

    Brena, Doadi Antonio

    2013-01-01

    O presente trabalho de pesquisa tem como principais objetivos comparar os métodos de inventários florestais sucessivos Independentes, Inventário Florestal Contínuo, e Dupla Amostragem, em relação a Amostragem com Repetição Parcial, analisar o efeito da estratificação na precisão das estimativas das médias volumétricas da primeira e segunda ocasiões e do crescimento, em cada um dos métodos; determinar o intervalo de tempo ótimo decorrido entre duas medições sucessivas. Os dados utilizados s...

  9. The bootstrap current in tokamaks

    International Nuclear Information System (INIS)

    The properties of the Hirshman equation for the bootstrap in the tokamak and the difference between it and the simpler Hinton-Hazeltine equation are discussed. The Hirshman model, which takes into account finite-aspect-ratio effects, is used to calculate the bootstrap current in the plasma in a circular cross section with Te = Ti. Approximate upper and lower bounds on the bootstrap current are obtained. These restrict the range of variation of the current as the temperature and density profiles vary. 16 refs., 9 figs

  10. Marketing aplicado em bibliotecas: análise de conteúdo dos artigos publicados em periódicos da Ciência da Informação

    Directory of Open Access Journals (Sweden)

    Adriana Stefani Cativelli

    2013-08-01

    Full Text Available Analisa os artigos publicados em periódicos referentes ao marketing no âmbito das bibliotecas. Visa verificar de que forma as bibliotecas estão utilizando o marketing em suas rotinas, reúne e examina a literatura existente sobre o assunto em questão e verifica qual a ação de marketing é explorada com maior frequência pelas bibliotecas. Caracteriza a pesquisa como documental de natureza exploratória, descritiva e quali-quantitativa. Constitui o corpus de análise com artigos publicados em periódicos nacionais de Ciência da Informação, no período de 2000 a 2011. Analisa os dados usando como base a técnica de análise de conteúdo proposta por Bardin. Verifica que dentre as diversas ferramentas que o marketing oferece, a mais utilizada pelas bibliotecas é a da filosofia gerencial. Conclui que a adoção do marketing pelas bibliotecas propiciou as bibliotecas realizarem trocas com seus usuários internos e externos, prestando mais atenção nas necessidades e desejos dos mesmos, além de instigar os gestores a repensar a forma de gerir as unidades de informação.

  11. Controle de plantas daninhas na cultura do milho-pipoca com herbicidas aplicados em pós-emergência Weed control in popcorn maize using post emergence herbicide

    Directory of Open Access Journals (Sweden)

    A. Jakelaitis

    2005-09-01

    Full Text Available Objetivou-se avaliar a eficiência de controle de plantas daninhas, a tolerância e a produção de milho-pipoca UFVM2 aos herbicidas atrazine (1.500 g ha-1, foramsulfuron + iodosulfuron methyl sodium + atrazine (15+1+1.500 e 30+2+1.500 g ha-1, foramsulfuron + iodosulfuron methyl sodium (15+1, 30+2, 45+3 e 60+4 g ha-1, nicosulfuron + atrazine (8+1.500 e 16+1.500 g ha-1 e nicosulfuron (16 g ha-1. A aplicação dos herbicidas foi realizada aos 25 dias após a emergência da cultura. As plantas daninhas predominantes na área foram Brachiaria plantaginea, Brachiaria decumbens e Ipomoea spp. Os herbicidas foramsulfuron + iodosulfuron methyl sodium, em todas as doses testadas, proporcionaram maiores índices de toxidez à cultura, aos 7, 14 e 28 dias após a aplicação dos tratamentos (DAA. Todas as combinações de herbicidas proporcionaram controle acima de 90% para B. plantaginea e B. decumbens, aos 28 DAA. O nicosulfuron aplicado isoladamente proporcionou controle de apenas 80% e o atrazine não controlou essas espécies daninhas. Para Ipomoea spp., nenhum tratamento herbicida proporcionou controle equivalente ao da testemunha capinada. A competição das plantas daninhas resultou em menores teores de clorofila total, N, P e K no tecido foliar das plantas de milho-pipoca e menor rendimento de grãos. Para o cultivar UFVM2, as sulfoniluréias isoladas ou associadas ao atrazine não afetaram o estado nutricional da cultura, o rendimento e a capacidade de expansão dos grãos de milho-pipoca.The efficiency of different herbicide combinations for weed control and tolerance and yield of UFVM2 popcorn maize were evaluated. The herbicide treatments and respective doses were: atrazine (1.500 g ha-1; foramsulfuron + iodosulfuron methyl sodium + atrazine (15+1+1.500 and 30+2+1.500 g ha-1; foramsulfuron + iodosulfuron methyl sodium (15+1, 30+2, 45+3, and 60+4 g ha-1; nicosulfuron + atrazine (8+1.500 and 16+1.500 g ha-1 and nicosulfuron (16 g ha-1. The

  12. The wild tapered block bootstrap

    DEFF Research Database (Denmark)

    Hounyo, Ulrich

    In this paper, a new resampling procedure, called the wild tapered block bootstrap, is introduced as a means of calculating standard errors of estimators and constructing confidence regions for parameters based on dependent heterogeneous data. The method consists in tapering each overlapping block......-of-the-art block-based method in terms of asymptotic accuracy of variance estimation and distribution approximation. For stationary time series, the asymptotic validity, and the favorable bias properties of the new bootstrap method are shown in two important cases: smooth functions of means, and M-estimators. The...... estimator for the sample mean is shown to be robust against heteroskedasticity of the wild tapered block bootstrap. This easy to implement alternative bootstrap method works very well even for moderate sample sizes....

  13. Linear algebra and bootstrap percolation

    CERN Document Server

    Balogh, József; Morris, Robert; Riordan, Oliver

    2011-01-01

    In $\\HH$-bootstrap percolation, a set $A \\subset [n]$ of initially `infected' vertices spreads by infecting vertices which are the only uninfected vertex in an edge of the hypergraph $\\HH \\subset \\P(n)$. A particular case of this is the $H$-bootstrap process, in which $\\HH$ encodes copies of $H$ in a graph $G$. We find the minimum size of a set $A$ that leads to complete infection when $G$ is a power of a complete graph and $H$ is a hypercube. The proof uses linear algebra, a technique that is new in bootstrap percolation, although standard in the study of weakly saturated graphs, which are equivalent to (edge) $H$-bootstrap percolation on a complete graph.

  14. Momento da chuva após a aplicação e a eficácia dos herbicidas sulfosate e glyphosate aplicados em diferentes formulações Rainfastness and glyphosate and sulfosate efficacy using different formulations

    Directory of Open Access Journals (Sweden)

    A.F.F. Pedrinho Júnior

    2002-04-01

    Full Text Available Com o objetivo de estudar a influência da chuva sobre o desempenho dos herbicidas sulfosate e glyphosate em diferentes formulações, foram conduzidos dois experimentos, um no inverno de 2000 e outro no verão de 2001, na Fazenda Experimental de Ensino e Pesquisa da Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal-SP. Os experimentos foram instalados segundo o delineamento experimental de blocos ao acaso, com quatro repetições, no arranjo fatorial de 4x5+1, ou seja, quatro tratamentos de herbicidas, cinco períodos sem chuva após a aplicação e uma testemunha, que não recebeu chuva. As formulações de glyphosate foram: SAqC (1,0 L ha-1, GrDA (0,5 kg ha-1, SAqC Transorb (0,75 L ha-1, mais o sulfosate SAqC (1,09 L ha¹. Os períodos sem chuva após a aplicação foram de 1, 2, 4, 6 e > 48 horas. Os herbicidas foram aplicados em pós-emergência das plantas daninhas, utilizando-se de um pulverizador costal, à pressão constante (mantida por ar comprimido de 30 lbf pol-2. A chuva foi simulada com um sistema de irrigação por aspersão. A lâmina de água variou entre 18 e 19 mm. Em ambas as épocas, a chuva simulada foi prejudicial à ação dos herbicidas, principalmente quando feita nos menores intervalos após a aplicação. Os sintomas de fitointoxicação apareceram mais rapidamente no verão. A formulação Transorb, comercializada como não sendo afetada pela chuva uma hora após a aplicação, não teve o desempenho esperado, tanto no inverno quanto no verão, para períodos de até seis horas sem chuva após a aplicação. O sulfosate apresentou o melhor controle geral das plantas avaliadas, quando se simulou chuva após seis horas, em ambas as épocas. A formulação GrDA foi a mais afetada pela ação da chuva em ambas as épocas.Two field assays were carried out to evaluate the rainfall effects on sulfosate and glyphosate herbicide activity, using different formulations, under two growing seasons (winter

  15. Bootstrapping Realized Multivariate Volatility Measures.

    OpenAIRE

    Donovon, Prosper; Goncalves, Silvia; Meddahi, Nour

    2013-01-01

    We study bootstrap methods for statistics that are a function of multivariate high frequency returns such as realized regression coefficients and realized covariances and correlations. For these measures of covariation, the Monte Carlo simulation results of Barndorff-Nielsen and Shephard (2004) show that finite sample distortions associated with their feasible asymptotic theory approach may arise if sampling is not too frequent. This motivates our use of the bootstrap as an altern...

  16. Deep Exploration via Bootstrapped DQN

    OpenAIRE

    Osband, Ian; Blundell, Charles; Pritzel, Alexander; Van Roy, Benjamin

    2016-01-01

    Efficient exploration in complex environments remains a major challenge for reinforcement learning. We propose bootstrapped DQN, a simple algorithm that explores in a computationally and statistically efficient manner through use of randomized value functions. Unlike dithering strategies such as epsilon-greedy exploration, bootstrapped DQN carries out temporally-extended (or deep) exploration; this can lead to exponentially faster learning. We demonstrate these benefits in complex stochastic ...

  17. Bootstrap current in a tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, C.E.

    1994-03-01

    The bootstrap current in a tokamak is examined by implementing the Hirshman-Sigmar model and comparing the predicted current profiles with those from two popular approximations. The dependences of the bootstrap current profile on the plasma properties are illustrated. The implications for steady state tokamaks are presented through two constraints; the pressure profile must be peaked and {beta}{sub p} must be kept below a critical value.

  18. Bootstrap current in a tokamak

    International Nuclear Information System (INIS)

    The bootstrap current in a tokamak is examined by implementing the Hirshman-Sigmar model and comparing the predicted current profiles with those from two popular approximations. The dependences of the bootstrap current profile on the plasma properties are illustrated. The implications for steady state tokamaks are presented through two constraints; the pressure profile must be peaked and βp must be kept below a critical value

  19. Bootstrap percolation on spatial networks

    OpenAIRE

    Jian Gao; Tao Zhou; Yanqing Hu

    2015-01-01

    Bootstrap percolation is a general representation of some networked activation process, which has found applications in explaining many important social phenomena, such as the propagation of information. Inspired by some recent findings on spatial structure of online social networks, here we study bootstrap percolation on undirected spatial networks, with the probability density function of long-range links’ lengths being a power law with tunable exponent. Setting the size of the giant active...

  20. Bootstrap Dynamical Symmetry Breaking

    Directory of Open Access Journals (Sweden)

    Wei-Shu Hou

    2013-01-01

    Full Text Available Despite the emergence of a 125 GeV Higgs-like particle at the LHC, we explore the possibility of dynamical electroweak symmetry breaking by strong Yukawa coupling of very heavy new chiral quarks Q . Taking the 125 GeV object to be a dilaton with suppressed couplings, we note that the Goldstone bosons G exist as longitudinal modes V L of the weak bosons and would couple to Q with Yukawa coupling λ Q . With m Q ≳ 700  GeV from LHC, the strong λ Q ≳ 4 could lead to deeply bound Q Q ¯ states. We postulate that the leading “collapsed state,” the color-singlet (heavy isotriplet, pseudoscalar Q Q ¯ meson π 1 , is G itself, and a gap equation without Higgs is constructed. Dynamical symmetry breaking is affected via strong λ Q , generating m Q while self-consistently justifying treating G as massless in the loop, hence, “bootstrap,” Solving such a gap equation, we find that m Q should be several TeV, or λ Q ≳ 4 π , and would become much heavier if there is a light Higgs boson. For such heavy chiral quarks, we find analogy with the π − N system, by which we conjecture the possible annihilation phenomena of Q Q ¯ → n V L with high multiplicity, the search of which might be aided by Yukawa-bound Q Q ¯ resonances.

  1. Bootstrapping quarks and gluons

    International Nuclear Information System (INIS)

    Dual topological unitarization (DTU) - the approach to S-matrix causality and unitarity through combinatorial topology - is reviewed. Amplitudes associated with triangulated spheres are shown to constitute the core of particle physics. Each sphere is covered by triangulated disc faces corresponding to hadrons. The leading current candidate for the hadron-face triangulation pattern employs 3-triangle basic subdiscs whose orientations correspond to baryon number and topological color. Additional peripheral triangles lie along the hadron-face perimeter. Certain combinations of peripheral triangles with a basic-disc triangle can be identified as quarks, the flavor of a quark corresponding to the orientation of its edges that lie on the hadron-face perimeter. Both baryon number and flavor are additively conserved. Quark helicity, which can be associated with triangle-interior orientation, is not uniformly conserved and interacts with particle momentum, whereas flavor does not. Three different colors attach to the 3 quarks associated with a single basic subdisc, but there is no additive physical conservation law associated with color. There is interplay between color and quark helicity. In hadron faces with more than one basic subdisc, there may occur pairs of adjacent flavorless but colored triangles with net helicity +-1 that are identifiable as gluons. Broken symmetry is an automatic feature of the bootstrap. T, C and P symmetries, as well as up-down flavor symmetry, persist on all orientable surfaces

  2. Bootstrapping Time Dilation Decoherence

    Science.gov (United States)

    Gooding, Cisco; Unruh, William G.

    2015-10-01

    We present a general relativistic model of a spherical shell of matter with a perfect fluid on its surface coupled to an internal oscillator, which generalizes a model recently introduced by the authors to construct a self-gravitating interferometer (Gooding and Unruh in Phys Rev D 90:044071, 2014). The internal oscillator evolution is defined with respect to the local proper time of the shell, allowing the oscillator to serve as a local clock that ticks differently depending on the shell's position and momentum. A Hamiltonian reduction is performed on the system, and an approximate quantum description is given to the reduced phase space. If we focus only on the external dynamics, we must trace out the clock degree of freedom, and this results in a form of intrinsic decoherence that shares some features with a proposed "universal" decoherence mechanism attributed to gravitational time dilation (Pikovski et al in Nat Phys, 2015). We note that the proposed decoherence remains present in the (gravity-free) limit of flat spacetime, emphasizing that the effect can be attributed entirely to proper time differences, and thus is not necessarily related to gravity. Whereas the effect described in (Pikovski et al in Nat Phys, 2015) vanishes in the absence of an external gravitational field, our approach bootstraps the gravitational contribution to the time dilation decoherence by including self-interaction, yielding a fundamentally gravitational intrinsic decoherence effect.

  3. Fosfitos aplicados em pós-colheita reduzem o mofo-azul em maçãs 'Fuji' e 'Gala' Postharvest application of phosphites reduces blue mold on 'Fuji' and 'Gala' apples

    Directory of Open Access Journals (Sweden)

    Luiz Eduardo Bassay Blum

    2007-08-01

    Full Text Available O mofo-azul (Penicillium expansum é uma podridão pós-colheita comum em maçãs (Malus domestica. O uso de substâncias menos ofensivas ao ambiente, como o fosfito (ácido fosforoso, é uma das alternativas de controle dessa doença. Visou-se, então, a avaliar neste estudo a eficiência de fosfito-K (40% de P2O5 e 30% de K2O e fosfito-CaB (10,7% de P2O5, 3,89% de Ca e 0,5% de B no controle do mofo-azul em maçãs 'Fuji' e 'Gala'. Os testes foram delineados em blocos ao acaso com seis repetições de 20 frutos cada. Os frutos foram desinfestados em hipoclorito de Na (1% por três minutos, lavados em água esterilizada, feridos (1mm de diâmetro e de profundidade com agulha em quatro pontos eqüidistantes, imersos nos tratamentos por 15 minutos e armazenados a 15-20ºC. Nas suspensões contaminadas com Penicillium expansum (10² conídios.mL-1, foram adicionadas as seguintes substâncias: benomil (150 mg.L-1, fosfito-K (0,5 a 1,5 mL.L-1 e fosfito-CaB (1,5 a 3,0 mL.L-1. As maçãs 'Fuji' e 'Gala' imersas em água com fosfito-CaB (1,5 mL.L-1, fosfito-K (0,5-1,5 mL.L-1 ou benomil (150 mg.L-1 foram menos afetadas pelo mofo-azul. A aplicação de fosfito-K (1,5 mL.L-1 ou benomil (150 mg.L-1 nos frutos foi mais eficiente do que os demais tratamentos no controle do mofo-azul.Blue mold (Penicillium expansum is a common postharvest disease of apples (Malus domestica. Applications of less hazardous substances to the environment, such as phosphite (phosphonic acid, is an alternative to the control of blue mold. The main goal of this study was to evaluate the efficiency of phosphite-K (40% P2O5 and 30% K2O and phosphite-CaB (10.7% P2O5, 3.89% Ca, and 0.5% B for the control of blue mold on 'Fuji' and 'Gala' apples. Tests were designed in randomized blocks with six replications of 20 fruits. Fruits were decontaminated with Na hypochlorite (1% for three minutes, washed with sterilized water, needle wounded (with a diameter and deepness of 1mm in four

  4. Double-bootstrap methods that use a single double-bootstrap simulation

    OpenAIRE

    Chang, Jinyuan; Hall, Peter

    2014-01-01

    We show that, when the double bootstrap is used to improve performance of bootstrap methods for bias correction, techniques based on using a single double-bootstrap sample for each single-bootstrap sample can be particularly effective. In particular, they produce third-order accuracy for much less computational expense than is required by conventional double-bootstrap methods. However, this improved level of performance is not available for the single double-bootstrap methods that have been s...

  5. Uni and multivariate methods applied to studies of phenotypic adaptability in maize (Zea mays L.=Métodos uni e multivariados aplicados em estudos de adaptabilidade fenotípica em milho (Zea mays L..

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Gerage

    2011-10-01

    Full Text Available The objective of this study was to evaluate the performance of 15 maize cultivars in seven locations in Paraná State, Brazil. Towards this aim, grain yield trials were conducted during two crop seasons, and centroid (multivariate and bissegmented regression (univariate methods were used to evaluate possible divergences among results obtained. The genotypes were evaluated in randomized complete blocks with three replications. The centroid method was effective for indicating productive potential of genotypes, allowing for classification of genotype adaptability and stability. Values of probability above 0.40 allowed more reliable genotype classification for both adaptability and stability. The STRIKE genotype presented wide adaptability and stability by both the centroid and bissegmented regression methods. The SHS 4040 and CD 306 genotypes were not indicated for planting, considering the tested environments. O objetivo deste estudo foi avaliar, por meio de ensaios de rendimento grãos, o desempenho de 15 híbridos de milho em sete locais no Estado de Paraná e em duas safras, pelos métodos centróide (multivariado e regressão bissegmentada (univariado, e avaliar possíveis divergências entre resultados obtidos por meio das duas metodologias. Os genótipos foram avaliados em delineamento de blocos completos casualizados com três repetiçõess. O método centróide foi efetivo na indicação de genótipos quanto o seu potencial produtivo, permitindo classificar genótipos não só quanto a adaptabilidade mas também quanto a estabilidade. Valores de probabilidade acima de 0,40 permitem classificar com maior confiabilidade os genótipos não só quanto à adaptabilidade, como também quanto à estabilidade. O genótipo STRIKE apresentou ampla adaptabilidade e estabilidade pelos métodos centróide e regressão bissegmentada. O genótipo SHS 4040 e CD 306 não devem ser indicados para cultivo, tomando-se como referência os ambientes testados.

  6. Avaliação de herbicidas aplicados em pós-emergência sobre e sob a palha em cana crua e o destino ambiental Evaluation of herbicides applied in post-emergence over and under straw in no-burn sugarcane and their environmental fate

    Directory of Open Access Journals (Sweden)

    L.L. Foloni

    2011-06-01

    Full Text Available O objetivo deste trabalho foi avaliar a eficiência de vários herbicidas isolados ou associados, aplicados em pós-emergência, na cultura da cana-soca, colhida mecanicamente no sistema cana crua, procurando evidenciar diferenças no seu desempenho quando aplicados sobre ou sob a palha, bem como, ainda dentro do conceito de sustentabilidade e avaliação de risco ambiental, quantificar os comportamentos nos quais esses produtos apresentam maior risco. O experimento foi conduzido no município de Bariri-SP, em áreas da Usina Della Colletta, Fazenda Santo Antonio, em área de cana-soca (cultivar RB 72 754 colhida mecanicamente. Foi utilizada a cana-soca de quarto corte, plantada no espaçamento de 1,40 m, em solo Argiloso Vermelho-Amarelo com 5% de declive. Empregou-se o delineamento experimental de blocos ao acaso com 14 tratamentos (trifloxysulfuron-sodium+ametrina 720 e 960; mesotrione 182 e 292,6; mesotrione+ametrina 292,6+1.500; mesotrione+trifloxysulfuron-sodium 182,8+720; metribuzin 2.680; trifloxysulfuron-sodium+ametrina + hexazinone+diuron 720+900; amicarbazone 45; hexazinone+diuron 1.320; trifloxysulfuron-sodium+sulfentrazone 720+700 (todos em gramas de ingrediente ativo; testemunha; testemunha capinada e quatro repetições, para cada tipo de aplicação (sobre e sob a palha disposta lado a lado. As avaliações realizadas foram: fitotoxicidade aparente, altura, estande, eficiência no controle da Digitaria horizontalis, Cenchrus echinatus, Emilia fosbergii e Sida cordifolia, números de internódios e o primeiro internódio. O modelo matemático foi o nível I de fugacidade, utilizando os compartimentos ar, água, solo, sedimento, biota, raiz, caule e folha. Os resultados mostraram que os herbicidas trifloxysulfuron + diuron, mesotrione, metribuzin, ametrina, hexazinone + diuron, amicarbazone e sulfentrazone isolados ou associados, aplicados em pós-emergência, em área total da cultura da cana-de-açúcar, foram altamente

  7. Orthogonal projections and bootstrap resampling procedures in the study of infraspecific variation

    Directory of Open Access Journals (Sweden)

    Luiza Carla Duarte

    1998-12-01

    Full Text Available The effect of an increase in quantitative continuous characters resulting from indeterminate growth upon the analysis of population differentiation was investigated using, as an example, a set of continuous characters measured as distance variables in 10 populations of a rodent species. The data before and after correction for allometric size effects using orthogonal projections were analyzed with a parametric bootstrap resampling procedure applied to canonical variate analysis. The variance component of the distance measures attributable to indeterminate growth within the populations was found to be substantial, although the ordination of the populations was not affected, as evidenced by the relative and absolute positions of the centroids. The covariance pattern of the distance variables used to infer the nature of the morphological differences was strongly influenced by indeterminate growth. The uncorrected data produced a misleading picture of morphological differentiation by indicating that groups of populations differed in size. However, the data corrected for allometric effects clearly demonstrated that populations differed morphologically both in size and shape. These results are discussed in terms of the analysis of morphological differentiation among populations and the definition of infraspecific geographic units.A influência do aumento em caracteres quantitativos contínuos devido ao crescimento indeterminado sobre a análise de diferenciação entre populações foi investigado utilizando como exemplo um conjunto de dados de variáveis craniométricas em 10 populações de uma espécie de roedor. Dois conjuntos de dados, um não corrigido para o efeito alométrico do tamanho e um outro corrigido para o efeito alométrico do tamanho utilizando um método de projeção ortogonal, foram analisados por um procedimento "bootstrap" de reamostragem aplicado à análise de variáveis canônicas. O componente de variância devido ao

  8. Saúde da criança: fatores de risco aplicados em programas de atenção básica à saúde Salud del niño: factores de riesgo aplicados en programas de atención básica a la salud Child health: risk factors applied in programs of primary health care

    OpenAIRE

    Cristiane Momoi; Silvane Ramos dos Santos Vasconcelos; Edina Mariko Koga da Silva; Maria Wany Louzada Strufaldi; Suely Midori Terao; Rosana Fiorini Puccini

    2012-01-01

    OBJETIVO: comparar as frequências dos fatores de risco em crianças matriculadas em unidades básicas de saúde (UBS) em dois períodos (1988-1989 e 2005-2006) e analisar a associação desses fatores com desnutrição, internação e óbito. MÉTODOS:Estudo de abordagem quantitativa, tipo coorte retrospectiva com amostra probabilística (n=414) de crianças menores de um ano matriculadas em duas UBSs do Embu (SP), em 2005-2006. Variáveis independentes: alto risco e presença de fatores de risco. Desfechos:...

  9. Bootstrap bias-adjusted GMM estimators

    OpenAIRE

    Ramalho, Joaquim J.S.

    2005-01-01

    The ability of six alternative bootstrap methods to reduce the bias of GMM parameter estimates is examined in an instrumental variable framework using Monte Carlo analysis. Promising results were found for the two bootstrap estimators suggested in the paper.

  10. Analytical bootstrap methods for censored data

    OpenAIRE

    Alan D. Hutson

    2002-01-01

    Analytic bootstrap estimators for the moments of survival quantities are derived. By using these expressions recommendations can be made as to the appropriateness of bootstrap estimation under censored data conditions.

  11. The Bootstrap Approach for Testing Skewness Persistence

    OpenAIRE

    Krishnamurty Muralidhar

    1993-01-01

    This study presents a new methodology for testing changes in skewness between time periods (or samples) using the bootstrap method. A Monte Carlo simulation experiment was conducted to compare the effectiveness of the bootstrap method with the method suggested by Lau, Wingender and Lau (1989) to test skewness persistence. The results show the bootstrap method to be more powerful than the other method. The bootstrap method was also used to determine the persistence of skewness in stock returns...

  12. Improving the Reliability of Bootstrap Tests

    OpenAIRE

    Russell Davidson; MacKinnon, James G.

    2000-01-01

    We first propose procedures for estimating the rejection probabilities for bootstrap tests in Monte Carlo experiments without actually computing a bootstrap test for each replication. These procedures are only about twice as expensive as estimating rejection probabilities for asymptotic tersts. We then propose procedures for computing modified bootstrap P values that will often be more accurate than ordinary ones. These procedures are closely related to the double bootstrap, but they are far ...

  13. Unsupervised model compression for multilayer bootstrap networks

    OpenAIRE

    ZHANG, XIAO-LEI

    2015-01-01

    Recently, multilayer bootstrap network (MBN) has demonstrated promising performance in unsupervised dimensionality reduction. It can learn compact representations in standard data sets, i.e. MNIST and RCV1. However, as a bootstrap method, the prediction complexity of MBN is high. In this paper, we propose an unsupervised model compression framework for this general problem of unsupervised bootstrap methods. The framework compresses a large unsupervised bootstrap model into a small model by ta...

  14. Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2013-01-01

    The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

  15. On the Asymptotic Accuracy of Efron's Bootstrap

    OpenAIRE

    Singh, Kesar

    1981-01-01

    In the non-lattice case it is shown that the bootstrap approximation of the distribution of the standardized sample mean is asymptotically more accurate than approximation by the limiting normal distribution. The exact convergence rate of the bootstrap approximation of the distributions of sample quantiles is obtained. A few other convergence rates regarding the bootstrap method are also studied.

  16. The bootstrap and edgeworth expansion

    CERN Document Server

    Hall, Peter

    1992-01-01

    This monograph addresses two quite different topics, in the belief that each can shed light on the other. Firstly, it lays the foundation for a particular view of the bootstrap. Secondly, it gives an account of Edgeworth expansion. Chapter 1 is about the bootstrap, witih almost no mention of Edgeworth expansion; Chapter 2 is about Edgeworth expansion, with scarcely a word about the bootstrap; and Chapters 3 and 4 bring these two themes together, using Edgeworth expansion to explore and develop the properites of the bootstrap. The book is aimed a a graduate level audience who has some exposure to the methods of theoretical statistics. However, technical details are delayed until the last chapter (entitled "Details of Mathematical Rogour"), and so a mathematically able reader without knowledge of the rigorous theory of probability will have no trouble understanding the first four-fifths of the book. The book simultaneously fills two gaps in the literature; it provides a very readable graduate level account of t...

  17. Financial bootstrapping : Motivation and usage of bootstrapping methods among SMEs in the tourism sector

    OpenAIRE

    Feti, Andreea; Dudele, Aiga

    2012-01-01

    Bootstrapping plays a vital role in the life of small and medium-sized enter-prises. By providing a large variety of financing alternatives bootstrapping ensures the existence of entrepreneurship, even though, too less attention is paid to bootstrapping in the specific literature. Therefore, the master thesis strives to eliminate the gaps in the theory by bringing new insights in the field of bootstrapping.The purpose of the master thesis is to investigate the usage of boot-strapping methods ...

  18. Controle de Brachiaria subquadripara e Brachiaria mutica através de diferentes herbicidas aplicados em pós-emergência Control of Brachiaria subquadripara and Brachiaria mutica by different herbicides applied post-emergence

    Directory of Open Access Journals (Sweden)

    C.A. Carbonari

    2003-01-01

    Full Text Available Foram realizados dois experimentos, com objetivo de avaliar a suscetibilidade de Brachiaria subquadripara e Brachiaria mutica a diferentes herbicidas aplicados em pósemergência. Os herbicidas e doses testados foram: glyphosate (Rodeo a 2.400, 3.360 e 4.320 g e.a. ha-1 com Aterbane a 0,5% v/v; glyphosate a 2.400, 3.360 e 4.320 g e.a. ha-1 com Silwet a 0,1% v/v; imazapyr (Arsenal a 750 e 1.500 g e.a. ha-1; e diquat (Reward a 400 e 800 g i.a. ha-1 com aplicação seqüencial. Manteve-se uma testemunha sem aplicação de herbicidas. As parcelas experimentais foram constituídas de caixas d'água de 60 x 60 x 45 cm, com 55 L de solo. A aplicação foi realizada quando as plantas se encontravam a 45 e 65 cm de altura para B. subquadripara e B. mutica, respectivamente. Foi utilizado um pulverizador costal, a pressão constante de CO2 (2 bars, pontas 110.02 XR, com um consumo de calda de 200 L ha-1. O controle foi avaliado visualmente, através de escala percentual de notas, além de se avaliar a massa seca das plantas. O herbicida glyphosate nas doses de 3.360 e 4.320 g e.a. ha-1, independentemente do adjuvante testado, proporcionou controle excelente para as duas espécies, porém as parcelas que receberam glyphosate a 2.400 g e.a. ha-1 apresentaram controle apenas satisfatório. O herbicida imazapyr nas doses de 750 e 1.500 g e.a. ha-1 proporcionou controle eficiente para B. subquadripara e excelente para B. mutica. Já o herbicida diquat, apesar de duas aplicações e independentemente da dose utilizada, mostrou-se ineficiente no controle das duas espécies.Two experiments were carried out to evaluate the susceptibility of Brachiaria subquadripara and Brachiaria mutica to different herbicides applied in post-emergence. The herbicides and doses used were: glyphosate (Rodeo at 2,400, 3,360 and 4,320 (g a.e. ha-1 plus Aterbane 0.5% v/v; glyphosate at 2,400, 3,360 and 4,320 (g a.e. ha-1 plus Silwet 0.1% v/v; imazapyr (Arsenal at 750 and 1,500 (g a

  19. Comportamento do herbicida metribuzin, aplicado isolado e em mistura com outros herbicidas, no controle de plantas daninhas em cafeeiros novos por dois anos consecutivos Effect of metribuzin, sprayed alone or in mixture with another herbicides, for weed control on young coffee trees, during two years

    Directory of Open Access Journals (Sweden)

    L.S.P. Cruz

    1985-12-01

    Full Text Available Para se conhecer o comportamento do herbicida metribuzin, aplicado isolaso ou em mistura com outros herbicidas residuais (napropamide, pendimethalin, alchlor, oryzalin e diuron no controle de plantas daninhas que comumente infestam cafeeiros em formação, foi conduzido um experimento de campo onde esse herbicida a 0,28; 0,42; 0,56 e 0,70 kg/ha em mistura com napropamide a 4,00 kg/ha pendimethalin a 1,00 kg/ha, alachlor a 2,40kg/ha, oryzalin a 1,50 kg/ha ou com diuron a 1,20 kg/ha, comparado com duas testemunhas , onde, em uma, o mato foi mantido a níveis não competitivos com a cultura, por meios mecânicos, e outra onde o mato foi deixado desenvolver-se naturalmente, sem nenhuma interferência. Foi incluído também um tratamento com diuron a 1,20 kg/ha. A infestação natural de plantas daninhas da área do experimento era formada pelas gramínas, capim-de-colçhão (Digitaria sanguinalis (L. Scop, capim - marmelada (Brachiaria plantaginea (Link. Hitch capim-pé-de-galinha (Elcusine indica (L. Gaertn., Capim-favorito (Rhynchelitrum roseum (Nees Stapf eet Hubb, e pelas dicotiledôneas beldroega (Portulaca oleracea L., picão-branco (Galinsoga parviflora Cav., caruru-de-mancha (Amarantus virides L., amendoim bravo (Euphorbia heterophylla L., picão-preto (Bidens pilosa L., mentruz (Lepidium virginicum L., quebra-pedra (Phyllantus cordovadensis, Muell Arg. e falsa-serralha (Emilia sachifolia DC. Os resultados dos dois anos foram semelhantes para cada tratamento. Metribuzin a 0,28 kg/ha em mistura com napropamide a 4,00 kg/ha, apresentam períodos de ação maior, seguidos da mistura de metribuzin, naquela mesma dose, com oryzalin a 1,50 kg/ha. Não foi contatado a presença de qualquer sintoma de intoxicação nos cafeeiros, em todos os tratamentos, até a última observação, realizada 210 dias após a segunda aplicação dos herbicidas.This paper reports on two years field trials carried out in Araras, SP, Brazil, on coffee tress with twenty

  20. Imobilização de nitrogênio da uréia e do sulfato de amônio aplicado em pré-semeadura ou cobertura na cultura de milho, no sistema plantio direto Nitrogen immobilization of urea and ammonium sulphate applied to maize before planting or top-dressing in a no-till system

    Directory of Open Access Journals (Sweden)

    Waldo Alejandro Ruben Lara Cabezas

    2007-08-01

    Full Text Available No segundo ano de estudo, sulfato de amônio (SA e uréia (U marcados com 15N foram aplicados na cultura do milho, em sucessão à aveia-preta (Avena strigosa Schieb., no sistema plantio direto, 33 dias antes e 10 dias depois da semeadura, na dose de 80 kg ha-1 de N, incorporados a 5-7 cm de profundidade, em sulcos espaçados de 0,8 m, nas entrelinhas do milho. O objetivo foi quantificar o N dos fertilizantes imobilizado no solo (15N orgânico, no sulco de adubação, e o N recuperado na planta nos estádios de 4-5 folhas, 11-12 folhas, florescimento e colheita. O delineamento experimental foi de blocos casualizados, efetuando-se a análise de variância em esquema fatorial 2 x 6 em pré-semeadura (duas fontes, U e SA, em seis épocas de amostragem e 2 x 3 (duas fontes em três épocas de amostragem em cobertura, com três repetições. O experimento foi realizado em Latossolo Vermelho ácrico típico fase Cerrado subcaducifólio, na Fazenda Floresta do Lobo - Pinusplan, em Uberlândia (MG. Na aplicação em pré-semeadura, a máxima imobilização foi observada aos 22 dias da aplicação do SA (9,1 kg ha-1 ou 11,4 % do N aplicado e aos 11 dias da aplicação da U (46,5 kg ha-1 ou 58,1 % do N aplicado. Até a colheita, a planta (parte aérea, grãos e raiz acumulou 66,0 e 47,9 kg ha-1 de N-SA e N-U, respectivamente, correspondendo à eficiência de absorção de 82,5 e 59,9 % do N aplicado. Na aplicação em cobertura, a imobilização do N fertilizante das duas fontes foi inferior a 12,5 % do N aplicado, em todas as fases de crescimento da planta, evidenciando que a biomassa do solo não concorreu com a planta pelo N fertilizante, sendo similar à quantificação realizada na safra 1999/2000. Na média das duas safras (1999/2001 e dos estádios de 11-12 folhas e florescimento, para cada kg de N fertilizante imobilizado, as plantas de milho absorveram 8,9 e 15,4 kg ha-1 de N-SA, em pré-semeadura e cobertura, respectivamente. Para N-U, esses

  1. Chain ladder method: Bayesian bootstrap versus classical bootstrap

    OpenAIRE

    Peters, Gareth W.; Mario V. W\\"uthrich; Shevchenko, Pavel V.

    2010-01-01

    The intention of this paper is to estimate a Bayesian distribution-free chain ladder (DFCL) model using approximate Bayesian computation (ABC) methodology. We demonstrate how to estimate quantities of interest in claims reserving and compare the estimates to those obtained from classical and credibility approaches. In this context, a novel numerical procedure utilising Markov chain Monte Carlo (MCMC), ABC and a Bayesian bootstrap procedure was developed in a truly distribution-free setting. T...

  2. Imobilização de nitrogênio da uréia e do sulfato de amônio aplicado em pré-semeadura ou cobertura na cultura de milho, no sistema plantio direto Nitrogen immobilization of urea and ammonium sulphate applied to maize before planting and as top-dressing in a no-till system

    Directory of Open Access Journals (Sweden)

    Waldo Alejandro Ruben Lara Cabezas

    2005-04-01

    Full Text Available Sulfato de amônio (SA e uréia (U marcados com 15N foram aplicados na cultura do milho, em sucessão à aveia preta (Avena strigosa Schieb., no sistema plantio direto, 43 dias antes e 31 dias depois da semeadura, na dose de 80 kg ha-1 de N, incorporados a 5-7 cm de profundidade, em sulcos espaçados de 0,8 m, nas entrelinhas do milho. O objetivo foi quantificar o N dos fertilizantes imobilizado no solo (15N-orgânico, no sulco de adubação, e o N-recuperado na planta nos estádios de 5-6 folhas, 11-12 folhas, florescimento e maturação fisiológica. O delineamento experimental foi inteiramente casualizado com parcelas subdivididas e três repetições. As parcelas foram constituídas das fontes U e SA, e as subparcelas, das épocas de aplicação de N. O experimento foi realizado em Latossolo Vermelho ácrico típico fase cerrado subcadocifólio, na Fazenda Floresta do Lobo-Pinusplan, em Uberlândia (MG. Na aplicação em pré-semeadura, a máxima imobilização foi observada aos 19 dias da aplicação do SA (13,3 kg ha-1 ou 16,6 % do N-aplicado e aos 40 dias da aplicação da U (13,7 kg ha-1 ou 17,1 % do N-aplicado. A maior quantidade de N fertilizante assimilado pela planta ocorreu entre os estádios de 5-6 e 11-12 folhas (44,1 e 23,4 % do N-SA e N-U, respectivamente. Na aplicação em cobertura, a imobilização do N-SA foi inferior a 3,5 % do N-aplicado, enquanto a imobilização do N-U foi de 9,9 kg ha-1 e 7,9 kg ha-1, respectivamente, nos estádios de 11-12 folhas e florescimento. Até o estádio de maturação fisiológica da cultura, 61,8 % do N-SA e 42,0 % do N-U foram recuperados pelo milho. Em média, nos estádios de 11-12 folhas e de florescimento, para cada kg de N-SA imobilizado, as plantas de milho recuperaram 8,0 e 16,7 kg ha-1 de N fertilizante em pré-semeadura e cobertura, respectivamente. Nos tratamentos com U, a média foi de 3,1 kg ha-1, independentemente da época de aplicação. As produtividades de grãos obtidas com

  3. Bootstrap Current in Spherical Tokamaks

    Institute of Scientific and Technical Information of China (English)

    王中天; 王龙

    2003-01-01

    Variational principle for the neoclassical theory has been developed by including amomentum restoring term in the electron-electron collisional operator, which gives an additionalfree parameter maximizing the heat production rate. All transport coefficients are obtained in-cluding the bootstrap current. The essential feature of the study is that the aspect ratio affects thefunction of the electron-electron collision operator through a geometrical factor. When the aspectratio approaches to unity, the fraction of circulating particles goes to zero and the contribution toparticle flux from the electron-electron collision vanishes. The resulting diffusion coefficient is inrough agreement with Hazeltine. When the aspect ratio approaches to infinity, the results are inagreement with Rosenbluth. The formalism gives the two extreme cases a connection. The theoryis particularly important for the calculation of bootstrap current in spherical tokamaks and thepresent tokamaks, in which the square root of the inverse aspect ratio, in general, is not small.

  4. Bootstrapping N=2 chiral correlators

    Science.gov (United States)

    Lemos, Madalena; Liendo, Pedro

    2016-01-01

    We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  5. Bootstrapping N=2 chiral correlators

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Madalena [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Liendo, Pedro [Humboldt-Univ. Berlin (Germany). IMIP

    2015-12-15

    We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  6. Quarks in the Bootstrap Era

    Science.gov (United States)

    Horn, D.

    2015-03-01

    The quark model emerged from the Gell-Mann-Ne'eman flavor SU(3) symmetry. Its development, in the context of strong interactions, took place in a heuristic theoretical framework, referred to as the Bootstrap Era. Setting the background for the dominant ideas in strong interaction of the early 1960s, we outline some aspects of the constituent quark model. An independent theoretical development was the emergence of hadron duality in 1967, leading to a realization of the Bootstrap idea by relating hadron resonances (in the s-channel) with Regge pole trajectories (in t- and u-channels). The synthesis of duality with the quark-model has been achieved by duality diagrams, serving as a conceptual framework for discussing many aspects of hadron dynamics toward the end of the 1960s.

  7. Conformal Bootstrap in Mellin Space

    CERN Document Server

    Gopakumar, Rajesh; Sen, Kallol; Sinha, Aninda

    2016-01-01

    We propose a new approach towards analytically solving for the dynamical content of Conformal Field Theories (CFTs) using the bootstrap philosophy. This combines the original bootstrap idea of Polyakov with the modern technology of the Mellin representation of CFT amplitudes. We employ exchange Witten diagrams with built in crossing symmetry as our basic building blocks rather than the conventional conformal blocks in a particular channel. Demanding consistency with the operator product expansion (OPE) implies an infinite set of constraints on operator dimensions and OPE coefficients. We illustrate the power of this method in the epsilon expansion of the Wilson-Fisher fixed point by computing operator dimensions and, strikingly, OPE coefficients to higher orders in epsilon than currently available using other analytic techniques (including Feynman diagram calculations). Our results enable us to get a somewhat better agreement of certain observables in the 3d Ising model, with the precise numerical values that...

  8. Bootstrapping N=2 chiral correlators

    International Nuclear Information System (INIS)

    We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  9. On a generalized bootstrap principle

    International Nuclear Information System (INIS)

    The S-matrices for non-simply-laced affine Toda field theories are considered in the context of a generalized bootstrap principle. The S-matrices, and in particular their poles, depend on a parameter whose range lies between the Coxeter numbers of dual pairs of the corresponding non-simply-laced algebras. It is proposed that only odd order poles in the physical strip with positive coefficients throughout this range should participate in the bootstrap. All other singularities have an explanation in principle in terms of a generalized Coleman-Thun mechanism. Besides the S-matrices introduced by Delius, Grisaru and Zanon, the missing case (F4(1), e6(2)), is also considered and provides many interesting examples of pole generation. (author)

  10. Bootstrap clustering for graph partitioning

    OpenAIRE

    Gambette, Philippe; Guénoche, Alain

    2011-01-01

    Given a simple undirected weighted or unweighted graph, we try to cluster the vertex set into communities and also to quantify the robustness of these clusters. For that task, we propose a new method, called bootstrap clustering which consists in (i) defining a new clustering algorithm for graphs, (ii) building a set of graphs similar to the initial one, (iii) applying the clustering method to each of them, making a profile (set) of partitions, (iv) computing a consensus partition for this pr...

  11. Conformal Bootstrap in Embedding Space

    CERN Document Server

    Fortin, Jean-François

    2016-01-01

    It is shown how to obtain conformal blocks from embedding space with the help of the operator product expansion. The minimal conformal block originates from scalar exchange in a four-point correlation functions of four scalars. All remaining conformal blocks are simple derivatives of the minimal conformal block. With the help of the orthogonality properties of the conformal blocks, the analytic conformal bootstrap can be implemented directly in embedding space, leading to a Jacobi-like definition of conformal field theories.

  12. Conformal bootstrap in embedding space

    Science.gov (United States)

    Fortin, Jean-François; Skiba, Witold

    2016-05-01

    It is shown how to obtain conformal blocks from embedding space with the help of the operator product expansion. The minimal conformal block originates from scalar exchange in a four-point correlation function of four scalars. All remaining conformal blocks are simple derivatives of the minimal conformal block. With the help of the orthogonality properties of the conformal blocks, the analytic conformal bootstrap can be implemented directly in embedding space, leading to a Jacobi-like definition of conformal field theories.

  13. Bootstrapping High Dimensional Time Series

    OpenAIRE

    Zhang, Xianyang; Cheng, Guang

    2014-01-01

    This article studies bootstrap inference for high dimensional weakly dependent time series in a general framework of approximately linear statistics. The following high dimensional applications are covered: (1) uniform confidence band for mean vector; (2) specification testing on the second order property of time series such as white noise testing and bandedness testing of covariance matrix; (3) specification testing on the spectral property of time series. In theory, we first derive a Gaussi...

  14. Modified Bootstrap Sensitometry In Radiography

    Science.gov (United States)

    Bednarek, Daniel R.; Rudin, Stephen

    1981-04-01

    A new modified bootstrap approach to sensitometry is presented which provides H and D curves that show almost exact agreement with those obtained using conventional methods. Two bootstrap techniques are described; both involve a combination of inverse-square and stepped-wedge modulation of the radiation field and provide intensity-scale sensitometric curves as appropriate for medical radiography. H and D curves obtained with these modified techniques are compared with those obtained for screen-film combinations using inverse-square sensitometry as well as with those obtained for direct x-ray film using time-scale sensitometry. The stepped wedge of the Wisconsin X-Ray Test Cassette was used in the bootstrap approach since it provides sufficient exposure latitude to encompass the useful density range of medical x-ray film. This approach makes radiographic sensitometry quick and convenient, allowing accurate characteristic curves to be obtained for any screen-film cassette using standard diagnostic x-ray equipment.

  15. Foliar biofertilizer applied in cover fertilization in the production of lettuce cv. Veronica El uso de bio-fertilizante foliar en la fertilización de cobertura de lechuga cv. Verónica Biofertilizante foliar aplicado em cobertura na produção de alface cv. Verônica.

    Directory of Open Access Journals (Sweden)

    Luniara Bastos dos Santos

    2010-05-01

    Full Text Available

    O uso de biofertilizantes via foliar pode ser utilizado como suplementação da adubação aplicada no solo e na correção mais rápida de possíveis deficiências. Devido a esse fato, essa prática tem sido cada vez mais utilizada pelos produtores em espécies olerícolas, especialmente folhosas. O presente trabalho objetivou avaliar o desempenho de plantas de alface crespa (cv. Verônica em resposta a doses de biofertilizante em diferentes concentrações aplicados via foliar. O ensaio foi instalado no delineamento em blocos casualizados com três repetições e cada parcela foi constituída por 64 plantas. Os tratamentos consistiram de biofertilizante aplicados via foliar, em solução, nas concentrações: 0%; 10%; 20% e 30% de biofertilizante. As características avaliadas foram: diâmetro da cabeça (DCAB, número de folhas (NF, altura de plantas (ALT e massa fresca total da parte aérea (MFTPA. Não houve efeito das concentrações de biofertilizantes sobre o DCAB. O NF, a ALT e MFTPA foram alteradas pelas concentrações de biofertilizantes, destacando a concentração de 20% que favoreceu a expressão dessas características.

    The use of biofertilizer through leaves can be a supplement of the applied fertilization in the soil and in the fastest correction of possible deficiencies. Due to that, this practice has been increasingly used by the producers in olericultural species, especially broadleaves. The present work aimed at evaluating the performance of lettuce plants (cv. Veronica in response to biofertilizer doses in different concentrations applied through leaves. The experiment was installed in the completely randomized blocks design with three replications and each plot was constituted by 64 plants. The treatments consisted of doses biofertilizer applied through leaves, in solution, in the concentrations: 0%; 10%; 20% and 30% of biofertilizer. The appraised characteristics were: diameter of

  16. Efficient bootstrap with weakly dependent processes

    OpenAIRE

    Francesco Bravo; Federico Crudu

    2012-01-01

    The efficient bootstrap methodology is developed for overidentified moment conditions models with weakly dependent observation. The resulting bootstrap procedure is shown to be asymptotically valid and can be used to approximate the distributions of t-statistics, J statistic for overidentifying restrictions, and Wald, Lagrange multiplier and distance statistics for nonlinear hypotheses. The asymptotic validity of the efficient bootstrap based on a computationally less demanding approximate k-...

  17. The wild bootstrap for multilevel models

    OpenAIRE

    Modugno, Lucia; Giannerini, Simone

    2015-01-01

    In this paper we study the performance of the most popular bootstrap schemes for multilevel data. Also, we propose a modified version of the wild bootstrap procedure for hierarchical data structures. The wild bootstrap does not require homoscedasticity or assumptions on the distribution of the error processes. Hence, it is a valuable tool for robust inference in a multilevel framework. We assess the finite size performances of the schemes through a Monte Carlo study. The results show that for...

  18. Theoretical comparisons of block bootstrap methods

    OpenAIRE

    Lahiri, S. N.

    1999-01-01

    In this paper, we compare the asymptotic behavior of some common block bootstrap methods based on nonrandom as well as random block lengths. It is shown that, asymptotically, bootstrap estimators derived using any of the methods considered in the paper have the same amount of bias to the first order. However, the variances of these bootstrap estimators may be different even in the first order. Expansions for the bias, the variance and the mean-squared error of different bloc...

  19. Multiquark hadrons in topological bootstrap

    International Nuclear Information System (INIS)

    We use the lowest-order topological bootstrap framework to calculate hadron masses by imposing duality on an infinite sum of ladder graphs generated from spherical unitarity. By making a certain simple dynamical approximation, we derive an explicit generic Regge-trajectory formula for any given process. If we then make certain reasonable dynamical assumptions and require simultaneous consistency for entire sets of processes, we are able to calculate the masses of all the lowest meson, baryon and multiquark states involving u and d quarks, and the Regge trajectories associated with each of them. The only arbitrary parameter is the mass of the rho, which merely serves to set the mass scale

  20. Saúde da criança: fatores de risco aplicados em programas de atenção básica à saúde Salud del niño: factores de riesgo aplicados en programas de atención básica a la salud Child health: risk factors applied in programs of primary health care

    Directory of Open Access Journals (Sweden)

    Cristiane Momoi

    2012-01-01

    Full Text Available OBJETIVO: comparar as frequências dos fatores de risco em crianças matriculadas em unidades básicas de saúde (UBS em dois períodos (1988-1989 e 2005-2006 e analisar a associação desses fatores com desnutrição, internação e óbito. MÉTODOS:Estudo de abordagem quantitativa, tipo coorte retrospectiva com amostra probabilística (n=414 de crianças menores de um ano matriculadas em duas UBSs do Embu (SP, em 2005-2006. Variáveis independentes: alto risco e presença de fatores de risco. Desfechos: evolução ponderal desfavorável, déficit nutricional, internação, óbito. Estatística: Qui-Quadrado e Odds Ratio. RESULTADOS: em 2005-2006, verificou-se: maior frequência de intercorrências neonatais e mães adolescentes; menor freqüência de desnutrição ou óbito de irmão 2z (17,9%; internações (21,8%; nenhum óbito. Baixo peso ao nascer associou-se à internação (OR=4,04;IC95%:1,35-12,04. CONCLUSÕES: Baixo peso ao nascer permanece, como importante fator de risco e a proporção de sobrepeso/obesidade indica necessidade de redirecionamento das ações de saúde da criança.OBJETIVO: comparar las frecuencias de los factores de riesgo en niños matriculados en unidades básicas de salud (UBS en dos períodos (1988-1989 y 2005-2006 y analizar la asociación de esos factores con desnutrición, internamiento y óbito. MÉTODOS: Estudio de abordaje cuantitativo, tipo cohorte retrospectivo con muestra probabilística (n=414 de niños menores de un año matriculados en dos UBSs de Embu (SP, en 2005-2006. Las variables independientes: alto riesgo y presencia de factores de riesgo. Desenlace: evolución ponderal desfavorable, déficit nutricional, internamiento, óbito. Estadística: Chi-Cuadrado y Odds Ratio. RESULTADOS: en 2005-2006, se verificó: mayor frecuencia de variaciones neonatales y madres adolescentes; menor frecuencia de desnutrición u óbito de hermano 2z (17,9%; internamientos (21,8%; ningún óbito. Bajo peso al nacer

  1. Detecção de emissão espontânea de luz em ensaios de colimetria aplicados ao monitoramento de efluentes sanitários Spontaneous light emission in coliforms test applied to wastewater monitoring

    OpenAIRE

    Samuel Ricardo dos Santos; José Euclides Stipp Paterniani; Cristiano de Mello Gallep

    2011-01-01

    No presente trabalho avaliou-se o potencial do emprego da técnica biofotônica ao monitoramento da qualidade microbiológica de efluentes sanitários, por meio da detecção de emissão ultrafraca de luz em testes envolvendo bactéria do grupo coliforme. Foram acompanhados os padrões de emissão de luz em câmara escura com o uso de efluente doméstico, antes e após tratamento, incubados em meio nutritivo à base de lactose e lauril triptose. O controle foi efetuado com o uso de cepa de Escherichia coli...

  2. Statistical bootstrap model and annihilations

    CERN Document Server

    Möhring, H J

    1974-01-01

    The statistical bootstrap model (SBM) describes the decay of single, high mass, hadronic states (fireballs, clusters) into stable particles. Coupling constants B, one for each isospin multiplet of stable particles, are the only free parameter of the model. They are related to the maximum temperature parameter T/sub 0/. The various versions of the SMB can be classified into two groups: full statistical bootstrap models and linear ones. The main results of the model are the following: i) All momentum spectra are isotropic; especially the exclusive ones are described by invariant phase space. The inclusive and semi-inclusive single-particle distributions are asymptotically of pure exponential shape; the slope is governed by T /sub 0/ only. ii) The model parameter B for pions has been obtained by fitting the multiplicity distribution in pp and pn at rest, and corresponds to T/sub 0/=0.167 GeV in the full SBM with exotics. The average pi /sup -/ multiplicity for the linear and the full SBM (both with exotics) is c...

  3. The (2, 0) superconformal bootstrap

    Science.gov (United States)

    Beem, Christopher; Lemos, Madalena; Rastelli, Leonardo; van Rees, Balt C.

    2016-01-01

    We develop the conformal bootstrap program for six-dimensional conformal field theories with (2, 0) supersymmetry, focusing on the universal four-point function of stress tensor multiplets. We review the solution of the superconformal Ward identities and describe the superconformal block decomposition of this correlator. We apply numerical bootstrap techniques to derive bounds on operator product expansion (OPE) coefficients and scaling dimensions from the constraints of crossing symmetry and unitarity. We also derive analytic results for the large spin spectrum using the light cone expansion of the crossing equation. Our principal result is strong evidence that the A1 theory realizes the minimal allowed central charge (c =25 ) for any interacting (2, 0) theory. This implies that the full stress tensor four-point function of the A1 theory is the unique unitary solution to the crossing symmetry equation at c =25 . For this theory, we estimate the scaling dimensions of the lightest unprotected operators appearing in the stress tensor operator product expansion. We also find rigorous upper bounds for dimensions and OPE coefficients for a general interacting (2, 0) theory of central charge c . For large c , our bounds appear to be saturated by the holographic predictions obtained from eleven-dimensional supergravity.

  4. Bootstrap percolation on spatial networks

    Science.gov (United States)

    Gao, Jian; Zhou, Tao; Hu, Yanqing

    2015-10-01

    Bootstrap percolation is a general representation of some networked activation process, which has found applications in explaining many important social phenomena, such as the propagation of information. Inspired by some recent findings on spatial structure of online social networks, here we study bootstrap percolation on undirected spatial networks, with the probability density function of long-range links’ lengths being a power law with tunable exponent. Setting the size of the giant active component as the order parameter, we find a parameter-dependent critical value for the power-law exponent, above which there is a double phase transition, mixed of a second-order phase transition and a hybrid phase transition with two varying critical points, otherwise there is only a second-order phase transition. We further find a parameter-independent critical value around -1, about which the two critical points for the double phase transition are almost constant. To our surprise, this critical value -1 is just equal or very close to the values of many real online social networks, including LiveJournal, HP Labs email network, Belgian mobile phone network, etc. This work helps us in better understanding the self-organization of spatial structure of online social networks, in terms of the effective function for information spreading.

  5. Bootstrap percolation in high dimensions

    CERN Document Server

    Balogh, Jozsef; Morris, Robert

    2009-01-01

    In r-neighbour bootstrap percolation on a graph G, a set of initially infected vertices A \\subset V(G) is chosen independently at random, with density p, and new vertices are subsequently infected if they have at least r infected neighbours. The set A is said to percolate if eventually all vertices are infected. Our aim is to understand this process on the grid, [n]^d, for arbitrary functions n = n(t), d = d(t) and r = r(t), as t -> infinity. The main question is to determine the critical probability p_c([n]^d,r) at which percolation becomes likely, and to give bounds on the size of the critical window. In this paper we study this problem when r = 2, for all functions n and d satisfying d \\gg log n. The bootstrap process has been extensively studied on [n]^d when d is a fixed constant and 2 \\le r \\le d, and in these cases p_c([n]^d,r) has recently been determined up to a factor of 1 + o(1) as n -> infinity. At the other end of the scale, Balogh and Bollobas determined p_c([2]^d,2) up to a constant factor, and...

  6. Recursos internos como diferenciais competitivos aplicados ao processo de adaptação estratégica em empresas do setor hoteleiro de Curitiba: estudo comparativo de casos

    OpenAIRE

    Teixeira, Rivanda Meira; Hocayen-da-Silva, Antônio João

    2010-01-01

    O setor hoteleiro de Curitiba, na segunda metade da década de 90, em função da instalação de montadoras e da transferência de diversas empresas multinacionais para a cidade, tornou-se atrativo para as redes hoteleiras nacionais e internacionais, uma vez que ocorreu aumento significativo na demanda pelos serviços de hospedagem. Buscou-se identificar, por meio de um estudo comparativo de casos, quais são os recursos internos que se destacam como diferenciais competitivos em empresas do se...

  7. A comparison of four different block bootstrap methods

    OpenAIRE

    Boris Radovanov; Aleksandra Marcikić

    2014-01-01

    The paper contains a description of four different block bootstrap methods, i.e., non-overlapping block bootstrap, overlapping block bootstrap (moving block bootstrap), stationary block bootstrap and subsampling. Furthermore, the basic goal of this paper is to quantify relative efficiency of each mentioned block bootstrap procedure and then to compare those methods. To achieve the goal, we measure mean square errors of estimation variance returns. The returns are calculated from 1250 daily ob...

  8. A Bayesian Bootstrap for a Finite Population

    OpenAIRE

    Lo, Albert Y.

    1988-01-01

    A Bayesian bootstrap for a finite population is introduced; its small-sample distributional properties are discussed and compared with those of the frequentist bootstrap for a finite population. It is also shown that the two are first-order asymptotically equivalent.

  9. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  10. Bootstrapping Phylogenetic Trees: Theory and Methods

    OpenAIRE

    Holmes, Susan

    2003-01-01

    This is a survey of the use of the bootstrap in the area of systematic and evolutionary biology. I present the current usage by biologists of the bootstrap as a tool both for making inferences and for evaluating robustness, and propose a framework for thinking about these problems in terms of mathematical statistics.

  11. Efficient bootstrap with weakly dependent processes

    NARCIS (Netherlands)

    Bravo, Francesco; Crudu, Federico

    2012-01-01

    The efficient bootstrap methodology is developed for overidentified moment conditions models with weakly dependent observation. The resulting bootstrap procedure is shown to be asymptotically valid and can be used to approximate the distributions of t-statistics, the J-statistic for overidentifying

  12. Ação do acibenzolar-S-metil aplicado em tubérculos e plantas de batata contra canela preta, incitada por Pectobacterium carotovorum subsp. atrosepticum atípica

    Directory of Open Access Journals (Sweden)

    Benelli Adilce I. H.

    2004-01-01

    Full Text Available A resistência sistêmica adquirida (SAR = systemic acquired resistance é um importante mecanismo de resistência a doenças em plantas. Neste estudo, a ação do acibenzolar-S-metil (ASM, derivado benzotidiazólico ativador de resistência em plantas foi avaliada sobre a brotação de tubérculos de batata (Solanum tuberosum e quanto à ação deste na indução de resistência à canela-preta, incitada por Pectobacterium carotovorum subsp. atrosepticum atípica (Pcaa, nas cultivares Asterix, Baronesa e Monalisa. Nas doses, 60, 120, 150, 200 e 250 mg i.a. l -1, o produto não inibiu o número de brotos. Contudo, em concentrações mais elevadas influenciou o comprimento destes. Em casa de vegetação, nas concentrações de 60 e 120 mg i.a. l -1 ASM, tanto no tratamento de tubérculos quanto no de aspersão nas plantas, a cultivar Asterix, respondeu ao tratamento do ASM, conferindo-lhe resistência à canela preta. Na cultivar Baronesa, a resposta ao ASM ocorreu somente no tratamento de tubérculos, e, para a cultivar Monalisa, não houve resposta ao ASM. Verifica-se, neste estudo, que houve ação do ASM sobre a indução de resistência e que este foi específico para determinadas cultivares de batata.

  13. Limitations of bootstrap current models

    International Nuclear Information System (INIS)

    We assess the accuracy and limitations of two analytic models of the tokamak bootstrap current: (1) the well-known Sauter model (1999 Phys. Plasmas 6 2834, 2002 Phys. Plasmas 9 5140) and (2) a recent modification of the Sauter model by Koh et al (2012 Phys. Plasmas 19 072505). For this study, we use simulations from the first-principles kinetic code NEO as the baseline to which the models are compared. Tests are performed using both theoretical parameter scans as well as core-to-edge scans of real DIII-D and NSTX plasma profiles. The effects of extreme aspect ratio, large impurity fraction, energetic particles, and high collisionality are studied. In particular, the error in neglecting cross-species collisional coupling—an approximation inherent to both analytic models—is quantified. Furthermore, the implications of the corrections from kinetic NEO simulations on MHD equilibrium reconstructions is studied via integrated modeling with kinetic EFIT. (paper)

  14. The N=2 superconformal bootstrap

    Science.gov (United States)

    Beem, Christopher; Lemos, Madalena; Liendo, Pedro; Rastelli, Leonardo; van Rees, Balt C.

    2016-03-01

    In this work we initiate the conformal bootstrap program for N=2 super-conformal field theories in four dimensions. We promote an abstract operator-algebraic viewpoint in order to unify the description of Lagrangian and non-Lagrangian theories, and formulate various conjectures concerning the landscape of theories. We analyze in detail the four-point functions of flavor symmetry current multiplets and of N=2 chiral operators. For both correlation functions we review the solution of the superconformal Ward identities and describe their superconformal block decompositions. This provides the foundation for an extensive numerical analysis discussed in the second half of the paper. We find a large number of constraints for operator dimensions, OPE coefficients, and central charges that must hold for any N=2 superconformal field theory.

  15. Influência do tipo e da quantidade de resíduos vegetais na eficácia de herbicidas aplicados em pré-emergência na cultura da soja Influence of the type and amount of crop residues in efficiency of herbicides applied pre-emergence in soybean

    Directory of Open Access Journals (Sweden)

    Núbia Maria Correia

    2007-01-01

    Full Text Available Com o objetivo de avaliar, em condições de campo e na região originalmente sob cerrado, os efeitos de resíduos vegetais [sorgo de cobertura (híbrido Cober Exp, milheto forrageiro (var. BN2, capim-pé-de-galinha (Eleusine coracana e capim-braquiária (Brachiaria brizantha] e duas quantidades de palha (3,0 e 5,5 t ha-1, no primeiro ano do estudo, e 3,5 e 5,8 t ha-1, no segundo na eficácia de herbicidas residuais (diclosulam e imazaquin aplicados em pré-emergência na cultura da soja, foi desenvolvido experimento, no ano agrícola 2003/2004 e repetido em 2004/2005, na fazenda Três Marcos, em Uberlândia (MG. Os herbicidas diclosulam e imazaquin não tiveram a eficácia afetada pela presença de palha na superfície do solo, independentemente da quantidade. Associados às coberturas, obteve-se melhor controle. No primeiro ano, após a instalação da cultura da soja, plantas de Eleusine coracana tornaram-se as principais infestantes na parcela de capim-pé-de-galinha.This work was conducted in the agricultural years 2003/04 and 2004/05, at the farm 'Três Marcos', Uberlândia, MG - Brazil to evaluate the effect of crop residues [coverage sorghum (hybrid Cober Exp, forage millet (var. BN2, finger millet (Eleusine coracana and St. Lucia Grass (Brachiaria brizantha] and two amounts of straw (3.0 and 5.5 t ha-1 in the first year and 3.5 and 5.8 t ha-1, in the second year in efficiency of herbicides (diclosulam and uimazaquin applied pre-emergence in soybean, 'Cerrado' conditions. The efficiency of herbicides diclosulam and imazaquin was not affected by the straw at any amount. Associated to the straw coverage, it had best weed control. In the first year, after the soybean field was installed, Eleusine coracana became the major weed species in the finger millet plot.

  16. Effect of crop residues applied isolated or in combination on the germination and seedling growth of horse purslane (Trianthema portulacastrum Efeito de resíduos vegetais aplicados isolados ou em associação na germinac ão e crescimento de plântulas de (Trianthema portulacastrum

    Directory of Open Access Journals (Sweden)

    A. Khaliq

    2011-03-01

    Full Text Available Soil incorporation of crop residues can lead to weed suppression by posing allelopathic and physical effects. Allelopathic potential of the crops sorghum, sunflower, brassica applied as sole or in combination for horse purslane (Trianthema portulacastrum suppression was evaluated in a pot investigation. Chopped crop residues alone and in combination were incorporated at 6 g kg-1 soil (12 t ha-1, and a weedy check was maintained. Germination traits time to start germination; time to 50% emergence, mean emergence time, emergence index and final germination percentage were negatively influenced by residue incorporation. Crop residues also exerted a pronounced negative influence on the shoot and root length of horse purslane. Significant suppression in leaf and root score and leaf area per plant was also observed. A combination of sorghum and sunflower residues accounted for maximum (71% seedling mortality. Soil incorporation of allelopathic crop residues can be employed for horse purslane management.A incorporação de resíduos vegetais pode levar à supressão de plantas daninhas devido a efeitos físicos, químicos e alelopáticos. O efeito alelopático potencial de resíduos de sorgo, girassol e canola, aplicados isolados ou em combinação, foi avaliado em relação à germinação e crescimento inicial de beldroegas-cavalo (Trianthema portulacastrum em experimento em vasos. Os resíduos vegetais foram picados e incorporados no solo na quantidade de 6 g kg-1 de solo, que é equivalente a 12 t ha-1; manteve-se também um tratamento sem resíduos. O tempo para iniciar a germinação, tempo de emergência de 50% (E50, tempo médio de emergência, índice de emergência e porcentagem final de germinação foram influenciados negativamente pela incorporação dos resíduos. A palhada também exerceu forte influência negativa sobre o crescimento da parte aérea e comprimento radicular de beldroegas-cavalo. Também foi observada supress

  17. Biorreator à membrana em batelada sequencial aplicado ao tratamento de esgoto visando à remoção de nutrientes Membrane sequencing batch reactor for the wastewater treatment aiming the nutrients removal

    Directory of Open Access Journals (Sweden)

    Tiago José Belli

    2012-06-01

    Full Text Available Neste trabalho, avaliou-se o desempenho de um biorreator à membrana em batelada sequencial para a remoção de nutrientes (nitrogênio e fósforo de esgoto sanitário. O reator, construído em escala piloto, foi operado durante 241 dias com tempo total de ciclo de 4 horas, sendo 5 minutos para alimentação, 55 minutos para a fase anóxica e 180 minutos para as fases de aeração e filtração (simultaneamente. Ao longo do monitoramento, foram empregados dois fluxos de filtração: 5,55 e 11,1 L.m-2.h-1, que resultaram nas taxas de troca volumétrica de 5 e 10%, respectivamente. As eficiências médias de remoção de Demanda Química de Oxigênio total, nitrogênio amoniacal e nitrogênio total alcançadas foram de 99, 98 e 96%, respectivamente. Em relação à remoção de fósforo, observou-se inicialmente um baixo rendimento do reator, sendo verificado ao longo do tempo, no entanto, uma tendência de melhora na remoção desse nutriente, atingindo eficiência média de 74% entre os dias 158 e 241. A utilização do fluxo de filtração de 5,55 L.m-2.h-1 proporcionou uma operação estável ao biorreator à membrana em batelada sequencial no que se refere à pressão transmembrana, tendo sido atingido o valor limite de 0,7 bar apenas uma vez em 181 dias de operação, ao passo que, com fluxo de 11,1 L.m-2.h-1, esse limite foi atingido 3 vezes em 55 dias.This study evaluated the performance of a membrane bioreactor sequencing batch, in pilot scale, to remove nutrients (nitrogen and phosphorus from domestic wastewater. The reactor was operated for 241 days with a total cycle time of 4 hours, with 5 minutes for feeding, 55 minutes for the anoxic phase and 180 minutes for the aeration and filtration phases (simultaneously. Throughout the monitoring, two filtration flows were employed: 5.5 and 11.1 (critical flux L.m-2.h-1, which resulted in the volume exchange rates of 5 and 10%, respectively. The removal efficiencies of total Chemical Oxygen

  18. Bootstrap current estimate in the ETE Tokamak

    International Nuclear Information System (INIS)

    First estimates of the bootstrap current in the ETE small aspect ratio tokamak using the Hirshman single ion collisionless model show that we can expect from 25 to 55% of total bootstrap current depending on the optimization level of the plasma parameter profiles. Higher levels of bootstrap current are limited by peaked pressure profiles and βpol values which must be kept under a critical level due to stability conditions. Different methods for the trapped particle fraction calculation are also illustrated in this paper. (author). 7 refs., 5 figs., 1 tab

  19. A model study in hadron statistical bootstrap

    CERN Document Server

    Hagedorn, Rolf

    1973-01-01

    In the framework of the statistical bootstrap the decay of a fireball is considered as an exact inverse of its statistical composition. This assumption leads to a bootstrap formulated in terms of integral equations for all kinds of distributions of the fireball's decay products. Solutions of the equations are obtained in terms of power series and of K-transforms and determine in the general case their asymptotic behaviour for large fireball mass. Relations to a thermodynamical description are established and illustrated by effective temperatures. The approach to the asymptotic limits is easy to investigate in a simplified linear bootstrap where the K-transforms can be more explicitly calculated. (30 refs).

  20. OntoSIGF - um sistema de informação geográfica baseado em ontologias aplicado à área florestal / OntoSIGF - a geographic information system based on ontologies applied to forestry

    Directory of Open Access Journals (Sweden)

    Bayron Thiengo Quinelato

    2008-09-01

    Full Text Available O desenvolvimento dos sistemas de navegação e posicionamentoglobal, tecnologias web, software, e hardware possibilitaram a rápida expansão do uso de Sistemas de Informação Geográfica (SIG. Ainformação é sempre distribuída e principalmente heterogenia. Contudo,especialistas de domínio usam conceitos e terminologias específi cas e usam diferentes parâmetros para descrever o modelo de um conceito. Estaheterogeneidade semântica das fontes de dados causa sérios problemas, que podem ser resolvidos aplicando o conceito de ontologias. O propósitodeste artigo é o de descrever uma arquitetura baseada em ontologiacapaz de registrar, descrever, organizar e integrar os conhecimentosde um domínio geográfi co fl orestal. Este modelo ontológico descreve os conceitos das informações geográfi cas e suas relações, facilitando o acesso às informações em arquivos e bases de dados, independente de onde essas informações estejam armazenadas

  1. Improving the Reliability of Bootstrap Tests with the Fast Double Bootstrap

    OpenAIRE

    Davidson, Russell; MacKinnon, James

    2006-01-01

    Two procedures are proposed for estimating the rejection probabilities of bootstrap tests in Monte Carlo experiments without actually computing a bootstrap test for each replication. These procedures are only about twice as expensive (per replication) as estimating rejection probabilities for asymptotic tests. Then a new procedure is proposed for computing bootstrap P values that will often be more accurate than ordinary ones. This “fast double bootstrap” is closely related to the double boot...

  2. The alignment of bootstrap current in tokamak

    International Nuclear Information System (INIS)

    By calculating the trapped particle fraction, solving the Grand-Shafranov equation describing plasma equilibrium, and using Harris model, the magnitude and alignment of the bootstrap current in tokamak are calculated and analysed under the conventional shear regimes and also the negative central shear regimes. The conclusion authors obtained are: through adjusting the profile parameters of plasma density, temperature and current, and the elongation k and triangularity d which describe the plasma shape, the alignment of bootstrap current profile with the equilibrium current profile can be produced; the negative central shear regimes are advantage ous to produce bootstrap current, and the profile of bootstrap current is well-aligned with the equilibrium current profile. By comparing authors' calculated results, the optimized parameters are obtained under the conventional shear and the negative central shear regimes

  3. iDESWEB: Frameworks CSS: Bootstrap

    OpenAIRE

    Yuste Torregrosa, Álvaro; Luján Mora, Sergio

    2012-01-01

    Framework CSS (herramientas y pautas), frameworks más famosos (BluePrint, 960 Grid System, YUI), Twitter Bootstrap, ejemplo de botones, ejemplo de uso de la rejilla. Sitio web del curso: http://idesweb.es/

  4. Adubação do algodoeiro: I - Influência dos adubos, quando aplicados em contato com as sementes, sobre a germinação Fertilizer experiments with cotton: I - Influence of fertilizer placement on the germination of seeds

    Directory of Open Access Journals (Sweden)

    O. S. Neves

    1956-01-01

    Full Text Available Os autores do presente artigo relatam os resultados de um ensaio realizado cm 1936-37, na Estação Experimental Central, para estudar a influência de alguns adubos sobre a germinação das sementes do algodoeiro. Para isso foram estabelecidas comparações entre canteiros sem adubo e canteiros adubados com 0-50-0, 0-50-50 e 10-50-50 kg/ha de N-P2O5-K2O e, ainda, com outros que receberam o dôbro dessas doses. N e K2O foram empregados respectivamente nas formas de salitre do Chile e cloreto de potássio: P2O5, em cada uma das três formas: farinha de ossos, Renania-fosfato e superfosfato. Comparou-se, também, a aplicação desses adubos nas covas e nos sulcos de plantio. Os 38 tratamentos do ensaio tiveram três repetições. Cada canteiro, de 25 m², constou de uma fileira de 20,90 m, espaçada de 1,20 m das vizinhas. Nas fileiras, 53 covas propriamente ditas foram plantadas a cêrea de 0,40 m uma das outras, cada cova recebendo seis sementes; no plantio em sulcos, de 0,40 em 0,40 m foram depositadas seis sementes. As correspondentes doses de adubo foram aplicadas em cada cova ou distribuídas continuamente nos sulcos, e, após ligeira mistura com a terra, semeou-se no solo adubado. Durante 36 dias a partir do plantio foram feitas contagens diárias das covas em que nasceram plantas. Dos dados assim obtidos concluiu-se que, aplicados isoladamente, nos sulcos ou nas covas, o superfosfato e a farinha de ossos não prejudicaram o "stand". Entretanto, as aplicações isoladas de Renania-fosfato, assim como as adubações em que ao fósforo, sob qualquer forma, se adicionou cloreto de potássio, e sobretudo as que, além dêsses adubos, também tiveram salitre, reduziram fortemente o "stand" quando aplicadas nas covas; empregadas nos sulcos, prejudicaram muito menos. Além de reduzir o "stand", o salitre e o cloreto de potássio retardaram a emergência das plantas. Em regra, os danos cresceram com a concentração de adubos em tôrno das sementes

  5. Quadrados mínimos parciais uni e multivariado aplicados na seleção genômica para características de carcaça em suínos

    Directory of Open Access Journals (Sweden)

    Camila Ferreira Azevedo

    2013-09-01

    Full Text Available A principal contribuição da genética molecular é a utilização direta das informações de DNA no processo de identificação de indivíduos geneticamente superiores. Sob esse enfoque, idealizou-se a seleção genômica ampla (Genome Wide Selection - GWS, a qual consiste na análise de marcadores SNPs (Single Nucleotide Polymorphisms amplamente distribuídos no genoma. Devido a esse grande número de SNPs, geralmente maior que o número de indivíduos genotipados, e à alta colinearidade entre eles, métodos de redução de dimensionalidade são requeridos. Dentre estes, destaca-se o método de regressão via Quadrados Mínimos Parciais (Partial Least Squares - PLS, que além de solucionar tais problemas, permite uma abordagem multivariada, considerando múltiplos fenótipos. Diante do exposto, objetivou-se aplicar e comparar a regressão PLS univariada (UPLS e multivariada (MPLS na GWS para características de carcaça em uma população F2 de suínos Piau×Comercial. Os resultados evidenciaram a superioridade do método MPLS, uma vez que este proporcionou maiores valores de acurácia em relação à abordagem univariada.

  6. Influência do tráfego de veículos comerciais em rodovias vicinais não pavimentadas: estudo de caso aplicado à VCS 346, Viçosa, MG

    Directory of Open Access Journals (Sweden)

    Taciano Oliveira da Silva

    2011-06-01

    Full Text Available Este artigo aborda a influência da variação da carga por eixo e da pressão de enchimento dos pneus sobre as deflexões superficiais recuperáveis previstas na estrutura de pavimento da estrada não pavimentada VCS 346, considerada representativa da malha vicinal do Município de Viçosa, MG. O programa de estudo considerou as seguintes análises: (i contagem volumétrica do tráfego, inclusive de veículos comerciais do tipo 2C; (ii deflexões recuperáveis previstas, em função dos dados disponíveis no estudo; (iii estrutura do pavimento, com dados referentes ao material das camadas. Com as análises, observou-se que a aplicação de níveis mais críticos de carregamento interferiu significativamente na vida útil do pavimento e, dependendo da combinação da carga por eixo e da pressão de enchimento dos pneus, a vida útil da estrada pode sofrer redução da ordem de 89%. Investigaram-se ainda, neste trabalho, dois métodos para dimensionar a espessura do revestimento primário para rodovias não pavimentadas. Um desses métodos foi o empírico, qual seja, o método do DNIT para dimensionamento de pavimentos flexíveis; e o outro foi fundamentado em teoria elástica para sistemas de camadas. Para o dimensionamento de estradas não pavimentadas melhoradas com uma camada de revestimento primário (sistema de duas camadas, concluiu-se que o procedimento mais adequado foi o emprego da teoria elástica.

  7. Investigating Mortality Uncertainty Using the Block Bootstrap

    Directory of Open Access Journals (Sweden)

    Xiaoming Liu

    2010-01-01

    Full Text Available This paper proposes a block bootstrap method for measuring mortality risk under the Lee-Carter model framework. In order to take account of all sources of risk (the process risk, the parameter risk, and the model risk properly, a block bootstrap is needed to cope with the spatial dependence found in the residuals. As a result, the prediction intervals we obtain for life expectancy are more accurate than the ones obtained from other similar methods.

  8. Theoretical Comparison of Bootstrap Confidence Intervals

    OpenAIRE

    Hall, Peter

    1988-01-01

    We develop a unified framework within which many commonly used bootstrap critical points and confidence intervals may be discussed and compared. In all, seven different bootstrap methods are examined, each being usable in both parametric and nonparametric contexts. Emphasis is on the way in which the methods cope with first- and second-order departures from normality. Percentile-$t$ and accelerated bias-correction emerge as the most promising of existing techniques. Certain other methods are ...

  9. Investigating Mortality Uncertainty Using the Block Bootstrap

    OpenAIRE

    Xiaoming Liu; W. John Braun

    2010-01-01

    This paper proposes a block bootstrap method for measuring mortality risk under the Lee-Carter model framework. In order to take account of all sources of risk (the process risk, the parameter risk, and the model risk) properly, a block bootstrap is needed to cope with the spatial dependence found in the residuals. As a result, the prediction intervals we obtain for life expectancy are more accurate than the ones obtained from other similar methods.

  10. Bootstrapping Reflective Systems: The Case of Pharo

    OpenAIRE

    Polito, Guillermo; Ducasse, Stéphane; Fabresse, Luc; Bouraqadi, Noury; Van Ryseghem, Benjamin

    2014-01-01

    Bootstrapping is a technique commonly known by its usage in language definition by the introduction of a compiler written in the same language it compiles. This process is important to understand and modify the definition of a given language using the same language, taking benefit of the abstractions and expression power it provides. A bootstrap, then, supports the evolution of a language. However, the infrastructure of reflective systems like Smalltalk includes, in addition to a compiler, an...

  11. Bootstrapping the European Gender Wage Gap

    OpenAIRE

    Rueckert, Eva

    2003-01-01

    This paper investigates the gender wage gap in Denmark, the Netherlands, France and Spain by bootstrapping the Oaxaca-Blinder decomposition. The bootstrap method is used to compute confidence intervals and to perform hypothesis tests for the (disaggregated) explained and unexplained components of the national earnings di?erentials between men and women. From the subset of paid employees selected from the European Community Household Panel (ECHP) it is revealed that the respective national gen...

  12. A new approach to bootstrap inference in functional coefficient models

    OpenAIRE

    Herwartz, Helmut; Xu, Fang

    2007-01-01

    We introduce a new, factor based bootstrap approach which is robust under heteroskedastic error terms for inference in functional coefficient models. Modeling the functional coefficient parametrically, the bootstrap approximation of an F statistic is shown to hold asymptotically. In simulation studies with both parametric and nonparametric functional coefficients, factor based bootstrap inference outperforms the wild bootstrap and pairs bootstrap approach according to its size features. Apply...

  13. The Bootstrap of Mean for Dependent Heterogeneous Arrays.

    OpenAIRE

    GONÇALVES, Silvia; White, Halbert

    2001-01-01

    Presently, conditions ensuring the validity of bootstrap methods for the sample mean of (possibly heterogeneous) near epoch dependent (NED) functions of mixing processes are unknown. Here we establish the validity of the bootstrap in this context, extending the applicability of bootstrap methods to a class of processes broadly relevant for applications in economics and finance. Our results apply to two block bootstrap methods: the moving blocks bootstrap of Künsch ( 989) and Liu and Singh ( 9...

  14. Maximum Likelihood and the Bootstrap for Nonlinear Dynamic Models

    OpenAIRE

    Goncalves, Silvia; White, Halbert

    2002-01-01

    The bootstrap is an increasingly popular method for performing statistical inference. This paper provides the theoretical foundation for using the bootstrap as a valid tool of inference for quasi-maximum likelihood estimators (QMLE). We provide a unified framework for analyzing bootstrapped extremum estimators of nonlinear dynamic models for heterogeneous dependent stochastic processes. We apply our results to two block bootstrap methods, the moving blocks bootstrap of Künsch (1989) and Liu a...

  15. A Score Based Approach to Wild Bootstrap Inference

    OpenAIRE

    Patrick M. Kline; Andres Santos

    2010-01-01

    We propose a generalization of the wild bootstrap of Wu (1986) and Liu (1988) based upon perturbing the scores of M-estimators. This "score bootstrap" procedure avoids recomputing the estimator in each bootstrap iteration, making it substantially less costly to compute than the conventional nonparametric bootstrap, particularly in complex nonlinear models. Despite this computational advantage, in the linear model, the score bootstrap studentized test statistic is equivalent to that of the con...

  16. Modelos matemáticos utilizados para descrever curvas de crescimento em aves aplicados ao melhoramento genético animal Mathematic models applied to describe growth curves in poultry applied to animal breeding

    Directory of Open Access Journals (Sweden)

    Patricia Tholon

    2009-10-01

    Full Text Available A utilização de funções matemáticas para descrever o crescimento animal é antiga. Elas permitem resumir informações em alguns pontos estratégicos do desenvolvimento ponderal e descrever a evolução do peso em função da idade do animal. Também é possível comparar taxas de crescimento de diferentes indivíduos em estados fisiológicos equivalentes. Os modelos de curvas de crescimento mais utilizados na avicultura são os derivados da função Richards, pois apresentam parâmetros que possibilitam interpretação biológica e portanto podem fornecer subsídios para seleção de uma determinada forma da curva de crescimento em aves. Também pode-se utilizar polinômios segmentados para descrever as mudanças de tendência da curva de crescimento animal. Entretanto, existem importantes fatores de variação para os parâmetros das curvas, como a espécie, o sistema de criação, o sexo e suas interações. A adequação dos modelos pode ser verificada pelos valores do coeficiente de determinação (R2, do quadrado médio do resíduo (QM res, do erro de predição médio (EPm, da facilidade de convergência dos dados e pela possibilidade de interpretação biológica dos parâmetros. Estudos envolvendo modelagem e descrição da curva de crescimento e seus componentes são amplamente discutidos na literatura. Porém, programas de seleção que visem a progressos genéticos para a forma da curva não são mencionados. A importância da avaliação dos parâmetros dos modelos de curvas de crescimento é ainda mais relevante já que os maiores ganhos genéticos para peso estão relacionados com seleção para pesos em idades próximas ao ponto de inflexão. A seleção para precocidade pode ser auxiliada com base nos parâmetros do modelo associados à variáveis que descrevem esta característica genética dos animais. Esses parâmetros estão relacionados a importantes características produtivas e reprodutivas e apresentam magnitudes

  17. Bootstrap current in NBI heated plasmas

    International Nuclear Information System (INIS)

    The expression for the bootstrap current density due to fast ions produced by NBI is derived in an axisymmetric magnetic field. From this expression the fast-ion-induced bootstrap current density is explicitly calculated in a large aspect ratio tokamak with circular cross-section. This bootstrap current is found to be quite small for parallel injection of neutral beams although it rapidly increases as it approaches perpendicular injection. In addition to the injection angle, this bootstrap current density depends strongly upon the values of the inverse aspect ratio an element of and the ratio υc (critical velocity)/υb (birth velocity). In perpendicular injection the ratio of the fast-ion-induced bootstrap current density to the bulk bootstrap current density is estimated for the typical parameters an element of = 0.1 and υc/υb = 0.5 as 0.09 (δβb/δr)/(δβe/δr), where βb and βe are the values of beta due to fast-ion and electron pressures, respectively. (author). 7 refs, 4 figs

  18. Atividade residual de herbicidas pré-emergentes aplicados na cultura da soja sobre o milheto cultivado em sucessão Effect of the residual activity of pre-emergent herbicides applied in soybean on pearl millet cultivated in succession

    Directory of Open Access Journals (Sweden)

    H.A. Dan

    2011-06-01

    Full Text Available O objetivo deste estudo foi avaliar a atividade residual de herbicidas utilizados no manejo de plantas daninhas em pré-emergência da cultura da soja, bem como verificar seus efeitos sobre o milheto cultivado em sucessão. Utilizaram-se parcelas de 80 m², em delineamento de blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas 5 x 4, correspondendo à aplicação dos herbicidas imazaquin (0,160 kg ha-1, diclosulam (0,035 kg ha-1, sulfentrazone (0,600 kg ha-1 e flumioxazin (0,050 kg ha-1 e uma testemunha, aplicados logo após a semeadura do cultivar de soja Msoy-6101. Nas subparcelas, realizou-se a semeadura do milheto, cultivar ADR-7010, em quatro períodos, correspondendo a 0, 40, 80 e 120 dias após a aplicação dos herbicidas (DAA. Durante a condução do ensaio, foram determinados os níveis de intoxicação, estande, altura e massa seca da parte aérea das plantas de milheto. No final do ciclo foi avaliado o rendimento de grãos da cultura. O híbrido de milheto ADR-7010 apresentou elevada sensibilidade com relação à atividade residual dos herbicidas sulfentrazone, diclosulam e imazaquin quando cultivado logo após a aplicação destes. A bioatividade dos herbicidas imazaquin, diclosulam e flumioxazin não foi suficiente para alterar o rendimento de grãos do milheto cultivado em sucessão à soja (120 DAA, mostrando que esse intervalo de tempo é suficiente para dissipação desses herbicidas. Dos herbicidas pré-emergentes avaliados, o sulfentrazone apresentou maior atividade residual, influenciado negativamente o rendimento da cultura durante o intervalo de tempo estudado.The objective of this study was to evaluate the persistence of herbicides applied in pre-emergence in soybean crop and the effects of these herbicides on pearl millet grown in succession. The herbicides imazaquin (0.160 kg ha-1, diclosulam (0.035 kg ha-1, sulfentrazone (0.600 kg ha-1, and fumioxazin (0.050 kg ha-1 were used immediately

  19. Ensaios de arrancamento e de empuxamento aplicados a taliscas de bambu encravadas em corpos-de-prova de solo-cimento Pull-out and push-in tests of bamboo splint embedded in soil-cement specimen

    Directory of Open Access Journals (Sweden)

    Wilza G. R. Lopes

    2002-12-01

    Full Text Available Neste trabalho, taliscas de bambu da espécie Dendrocalamus giganteus, engastadas em corpos-de-prova de solo-cimento, foram submetidas a ensaios de arrancamento (pull-out e de empuxamento (push-out a fim de se determinar sua resistência de aderência. Para esta finalidade, foi utilizado um solo-cimento feito a partir de um solo arenoso que continha aproximadamente 70% de areia. Corpos-de-prova de solo-cimento, de 15 cm de diâmetro e 30 cm de altura, foram moldados com 14% de cimento na umidade ótima de 10,7%. As taliscas de bambu foram preparadas com 2 cm de largura e comprimentos de 40, 50 e 60 cm, para o ensaio de arrancamento, e de 70 cm para o ensaio de empuxamento. Metade das taliscas foi deixada sem tratamento impermeabilizante e a outra metade foi revestida com emulsão asfáltica, impregnada com areia limpa grossa, para produzir uma superfície áspera e garantir melhor aderência com o solo-cimento. Os corpos-de-prova de solo-cimento com as taliscas de bambu engastadas, foram deixados a curar em câmara úmida, durante 28 d, antes de serem ensaiados. Ambos os ensaios foram realizados em uma máquina universal de ensaio adaptada, sendo as deformações medidas com um relógio comparador aferido, de sensibilidade igual a 0,01 mm. A resistência de aderência, quer fosse determinada pelo ensaio de arrancamento quer pelo ensaio de empuxamento, foi obtida dividindo-se a máxima carga verificada no ensaio pela área lateral da talisca de bambu efetivamente engastada no solo-cimento. Os melhores resultados foram obtidos sem aplicação de material impermeabilizante, para o ensaio de arrancamento, enquanto nenhuma diferença foi observada entre os dois tratamentos para o ensaio de empuxamento.In this study, Dendrocalamus giganteus bamboo splints (split culm embedded in soil-cement specimens were submitted to pull-out and push-in tests in order to determine its bonding strength. For this purpose a sandy soil was utilized. The 15.0 cm diameter

  20. Análise econômico-financeira da utilização do GN em sistemas de cogeração aplicados a instalações prediais

    Directory of Open Access Journals (Sweden)

    Marcia Ferreira Cristaldo

    2009-06-01

    Full Text Available Sistemas de cogeração podem ampliar a capacidade instalada para geração de energia no Brasil. Podem também aumentar a confiabilidade do sistema de transmissão, diversificando a matriz energética e ampliando as oportunidades de negócio para o capital privado no mercado brasileiro. O Brasil apresenta expressivo potencial para a implantação de pequenas plantas de cogeração, sobretudo no setor de serviços (terciário, onde se concentra um número considerável de pequenos estabelecimentos comerciais com necessidades de energia elétrica, vapor, água quente e/ou água gelada (para refrigeração. Neste trabalho é apresentada uma metodologia de apoio aos novos usuários desse setor, a qual permite a análise da viabilidade econômico-financeira da utilização do gás natural em sistemas de cogeração como alternativa à eletricidade. Esta metodologia é baseada na técnica de dinâmica de sistemas, que permite tanto a representação do comportamento dinâmico das variáveis envolvidas, como a análise dos efeitos da competição dessas duas fontes de energia (gás natural e energia elétrica junto ao mercado consumidores.

  1. Aproveitamento pelo trigo do nitrogênio residual da crotalária (Crotalaria juncea e da uréia aplicado ao solo em cultivo precedente Recovery by wheat of residual nitrogen from crotalária (Crotalaria juncea and urea of previous crop soil fertilization

    Directory of Open Access Journals (Sweden)

    Anderson Lange

    2009-09-01

    Full Text Available O cultivo de adubos verdes no sistema produtivo tem por objetivo o fornecimento de nitrogênio ao solo. Porém, muitas vezes os benefícios não são a curto prazo. Nesse sentido, acompanhar a taxa de fornecimento de nitrogênio proveniente dos resíduos ao longo dos anos se faz necessário. O objetivo do trabalho foi avaliar o aproveitamento do nitrogênio residual no solo do adubo verde (Crotalaria juncea L.-15N e da uréia-15N, em fertilização conjugada e separada, no segundo ano de cultivo pelo trigo (Triticum aestivum L.. O experimento foi desenvolvido em vasos com 4kg de solo (Latossolo Vermelho distrófico típico, em delineamento inteiramente casualizado com cinco tratamentos e quatro repetições. As quantidades de 15N residual do primeiro cultivo eram: Uréia-15N (11,2mg kg-1 de 15N; Crotalária juncea-15N (85mg kg-1de 15N; Uréia-15N+crotalária (19,8mg kg-1 de 15N; Crotalária juncea-15N+uréia (81,6mg kg-1de 15N; Controle (sem adição de fontes de N. Todos os tratamentos receberam 36mg kg-1 de N-uréia (sem marcação em cobertura. Foram avaliados a recuperação do 15N residual das fontes, a massa de matéria seca, a concentração e o conteúdo de N nas plantas. A recuperação do N-uréia residual aplicado isoladamente foi superior quando comparada à recuperação do N-crotalária ou crotalária mais uréia, sem, contudo, influenciar o acúmulo de massa e a nutrição das plantas de trigo. No sistema solo-planta, a porcentagem de recuperação do N-crotalária foi igual ao N-uréia. Após dois anos de cultivo do solo em vasos sem aparentes perdas por percolação e lixiviação, em torno de 26% do N-uréia e 75% do N-crotalária aplicados no primeiro cultivo ainda se encontram no solo, evidenciando o benefício da incorporação de adubo verde no fornecimento de N gradativamente ao sistema.The cultivation of green manures in the production system aims to supply nitrogen to the soil, but often the benefits are not in the short

  2. Bootstrap states of the Z-pinch

    International Nuclear Information System (INIS)

    Steady bootstrap states of a Z-pinch are investigated both in absence and in presence of an imposed axial magnetic field, in terms of MHD theory with classical resistivity. The results indicate that bootstrap operation should become possible for certain classes of plasma profiles and that such operation can lead to higher bootstrap currents in a Z-pinch without axial magnetic field than in a tokamak-like case under similar plasma conditions. The ratio between the latter and the former currents is of the order of the square root of the beta value in the tokamak-like case. A simple numerical example is given on boot-strap operation in the Z-pinch. Neoclassical or anomalous diffusion will increase the diffusion velocity of the plasma but are not expected to affect the main physical features of the present results. This applies also to the kinetic effects in the weak-field region near the axis of the Z-pinch, because these effects can largely be described by MHD-like equations for a steady equilibrium. Bootstrap operation and the technical difficulty in realizing a volume distribution of particle sinks introduce certain constraints on the plasma and current profiles. This has to be taken into account in a stability analysis. The latter cannot only be performed in terms of MHD-like theory but has to be based on kinetic theory including large Larmor radius (LLR) effects. (author)

  3. The bootstrap conditions for the gluon Reggeization

    International Nuclear Information System (INIS)

    Compatibility of gluon Reggeization with s-channel unitarity requires the vertices of the Reggeon interactions to satisfy a series of bootstrap conditions. In order to derive, in the next-to-leading order (NLO), conditions related to the gluon production amplitudes, we calculate the s-channel discontinuities of these amplitudes and compare them with those required by the Reggeization. It turns out that these conditions include the so called strong bootstrap conditions for the kernel and for the impact factors of scattering particles, which were proposed earlier without derivation, and recently were proved to be satisfied. Besides this, there is a new bootstrap condition, which relates a number of Reggeon vertices and the gluon trajectory. (orig.)

  4. Stability of LHD plasmas with bootstrap current

    International Nuclear Information System (INIS)

    Since a net toroidal current flowing in the direction increasing the rotational transform (t) has a destabilizing contribution in the Mercier criterion in the LHD configuration, two approaches are considered so that the bootstrap current should not flow in the direction. One is the change in the geometry by unbalancing the helical coil currents. The other is the enhancement of the collisionality in the plasma. In both cases, the bootstrap current can flow in the direction where t is decreased, because the geometrical factor in the limit of the 1/ν regime is drastically changed. The enhancement of the bumpiness and the l=1 components in the magnetic field is essential in the change. In these equilibria, the reduction of t by the bootstrap current results in the increase of the Shafranov shift, which leads to the improvement of the Mercier criterion. (author)

  5. Bootstrap Percolation on Random Geometric Graphs

    CERN Document Server

    Bradonjić, Milan

    2012-01-01

    Bootstrap percolation has been used effectively to model phenomena as diverse as emergence of magnetism in materials, spread of infection, diffusion of software viruses in computer networks, adoption of new technologies, and emergence of collective action and cultural fads in human societies. It is defined on an (arbitrary) network of interacting agents whose state is determined by the state of their neighbors according to a threshold rule. In a typical setting, bootstrap percolation starts by random and independent "activation" of nodes with a fixed probability $p$, followed by a deterministic process for additional activations based on the density of active nodes in each neighborhood ($\\th$ activated nodes). Here, we study bootstrap percolation on random geometric graphs in the regime when the latter are (almost surely) connected. Random geometric graphs provide an appropriate model in settings where the neighborhood structure of each node is determined by geographical distance, as in wireless {\\it ad hoc} ...

  6. Selfconsistent RF driven and bootstrap currents

    International Nuclear Information System (INIS)

    In order to achieve steady-state high performance regimes in tokamaks, it is important to sustain and control the pressure and magnetic shear profiles in high bootstrap current plasmas. RF waves can be used to achieve such a goal. Then the bootstrap current fraction must be calculated selfconsistently with RF induced currents, taking into account possible synergistic effects resulting from the distortion of the electron velocity-space distribution. Results obtained with a new 3-D code that solves the electron drift kinetic equation to study the synergistic effects are presented. While synergism between bootstrap and LH-driven currents remains modest, it may reach up to 30-40% for the case of EC current drive provided the plasma parameters are properly chosen. (author)

  7. USEFULNESS OF BOOTSTRAPPING IN PORTFOLIO MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Boris Radovanov

    2012-12-01

    Full Text Available This paper contains a comparison of in-sample and out-of-sample performances between the resampled efficiency technique, patented by Richard Michaud and Robert Michaud (1999, and traditional Mean-Variance portfolio selection, presented by Harry Markowitz (1952. Based on the Monte Carlo simulation, data (samples generation process determines the algorithms by using both, parametric and nonparametric bootstrap techniques. Resampled efficiency provides the solution to use uncertain information without the need for constrains in portfolio optimization. Parametric bootstrap process starts with a parametric model specification, where we apply Capital Asset Pricing Model. After the estimation of specified model, the series of residuals are used for resampling process. On the other hand, nonparametric bootstrap divides series of price returns into the new series of blocks containing previous determined number of consecutive price returns. This procedure enables smooth resampling process and preserves the original structure of data series.

  8. Bootstrap percolation: a renormalisation group approach

    International Nuclear Information System (INIS)

    In bootstrap percolation, sites are occupied at random with probability p, but each site is considered active only if at least m of its neighbours are also active. Within an approximate position-space renormalization group framework on a square lattice we obtain the behaviour of the critical concentration p (sub)c and of the critical exponents ν and β for m = 0 (ordinary percolation), 1,2 and 3. We find that the bootstrap percolation problem can be cast into different universality classes, characterized by the values of m. (author)

  9. BOOTSTRAPPING FOR EXTRACTING RELATIONS FROM LARGE CORPORA

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new approach of relation extraction is described in this paper. It adopts a bootstrapping model with a novel iteration strategy, which generates more precise examples of specific relation. Compared with previous methods, the proposed method has three main advantages: first, it needs less manual intervention; second, more abundant and reasonable information are introduced to represent a relation pattern; third, it reduces the risk of circular dependency occurrence in bootstrapping. Scalable evaluation methodology and metrics are developed for our task with comparable techniques over TianWang 100G corpus. The experimental results show that it can get 90% precision and have excellent expansibility.

  10. Early Stop Criterion from the Bootstrap Ensemble

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Larsen, Jan; Fog, Torben L.

    1997-01-01

    This paper addresses the problem of generalization error estimation in neural networks. A new early stop criterion based on a Bootstrap estimate of the generalization error is suggested. The estimate does not require the network to be trained to the minimum of the cost function, as required by...... other methods based on asymptotic theory. Moreover, in contrast to methods based on cross-validation which require data left out for testing, and thus biasing the estimate, the Bootstrap technique does not have this disadvantage. The potential of the suggested technique is demonstrated on various time...

  11. Conference on Bootstrapping and Related Techniques

    CERN Document Server

    Rothe, Günter; Sendler, Wolfgang

    1992-01-01

    This book contains 30 selected, refereed papers from an in- ternational conference on bootstrapping and related techni- ques held in Trier 1990. Thepurpose of the book is to in- form about recent research in the area of bootstrap, jack- knife and Monte Carlo Tests. Addressing the novice and the expert it covers as well theoretical as practical aspects of these statistical techniques. Potential users in different disciplines as biometry, epidemiology, computer science, economics and sociology but also theoretical researchers s- hould consult the book to be informed on the state of the art in this area.

  12. Bootstrapped models for intrinsic random functions

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, K.

    1988-08-01

    Use of intrinsic random function stochastic models as a basis for estimation in geostatistical work requires the identification of the generalized covariance function of the underlying process. The fact that this function has to be estimated from data introduces an additional source of error into predictions based on the model. This paper develops the sample reuse procedure called the bootstrap in the context of intrinsic random functions to obtain realistic estimates of these errors. Simulation results support the conclusion that bootstrap distributions of functionals of the process, as well as their kriging variance, provide a reasonable picture of variability introduced by imperfect estimation of the generalized covariance function.

  13. The Stacked Leading Indicators Dynamic Factor Model: A Sensitivity Analysis of Forecast Accuracy using Bootstrapping

    OpenAIRE

    Daniel Grenouilleau

    2006-01-01

    The paper introduces an approximate dynamic factor model based on the extraction of principal components from a very large number of leading indicators stacked at various lags. The model is designed to produce short-term forecasts that are computed with the EM algorithm implemented with the first few eigenvectors ordered by descending eigenvalues. A cross-sectional bootstrap experiment is used to shed light on the sensitivity of the factor model to factor selection and to sampling uncertainty...

  14. The use of the bootstrap in the analysis of case-control studies with missing data

    DEFF Research Database (Denmark)

    Siersma, Volkert Dirk; Johansen, Christoffer

    2004-01-01

    nonparametric bootstrap, bootstrap confidence intervals, missing values, multiple imputation, matched case-control study......nonparametric bootstrap, bootstrap confidence intervals, missing values, multiple imputation, matched case-control study...

  15. A Large Sample Study of the Bayesian Bootstrap

    OpenAIRE

    Lo, Albert Y.

    1987-01-01

    An asymptotic justification of the Bayesian bootstrap is given. Large-sample Bayesian bootstrap probability intervals for the mean, the variance and bands for the distribution, the smoothed density and smoothed rate function are also provided.

  16. Non-Parametric Data Dependent Bootstrap for Conditional Moment Model

    OpenAIRE

    Bruce E. Hansen

    2000-01-01

    A new non-parametric bootstrap is introduced for dependent data. The bootstrap is based on a weighted empirical-likelihood estimate of the one-step-ahead conditional distribution, imposing the conditional moment restrictions implied by the model. This is the first dependent-data bootstrap procedure which imposes conditional moment restrictions on a bootstrap distribution. The method can be applied to form confidence intervals and p-values from hypothesis tests in Generalized Method of Moments...

  17. Wild bootstrap of the mean in the infinite variance case

    OpenAIRE

    Giuseppe Cavaliere; Iliyan Georgiev; Robert Taylor, A. M.

    2011-01-01

    It is well known that the standard i.i.d. bootstrap of the mean is inconsistent in a location model with infinite variance (alfa-stable) innovations. This occurs because the bootstrap distribution of a normalised sum of infinite variance random variables tends to a random distribution. Consistent bootstrap algorithms based on subsampling methods have been proposed but have the drawback that they deliver much wider confidence sets than those generated by the i.i.d. bootstrap owing to the fact ...

  18. uniform bootstrap confidence bands for bounded influence curve estimators

    OpenAIRE

    Härdle, Wolfgang Karl; Ritov, Ya‘acov; Wang, Weining

    2013-01-01

    We consider theoretical bootstrap "coupling" techniques for nonparametric robust smoothers and quantile regression, and verify the bootstrap improvement. To cope with curse of dimensionality, a variant of "coupling" bootstrap techniques are developed for additive models with both symmetric error distributions and further extension to the quantile regression framework. Our bootstrap method can be used in many situations like constructing con dence intervals and bands. We demonstrate the bootst...

  19. Produção de tomate hidropônico utilizando rejeito da dessalinização na solução nutritiva aplicados em diferentes épocas Hydroponic tomato production using reject of desalination in the nutrient solution applied at different stages

    Directory of Open Access Journals (Sweden)

    Christiano R. Cosme

    2011-05-01

    Full Text Available O objetivo desta pesquisa foi avaliar a resposta do tomateiro (Lycopersicon esculentum em cultivo hidropônico, adicionando água de rejeito da dessalinização na composição da solução nutritiva, obtendo-se três níveis de salinidade da solução nutritiva: 7,1; 8,7 e 10,1 dS m-1, além da testemunha (sem adição do rejeito: 2,1 dS m-1, iniciando-se sua aplicação em diferentes estágios de desenvolvimento da cultura: 7; 32 e 58 dias após o transplantio (DAT. O delineamento foi inteiramente casualizado, com 9 tratamentos e três repetições cada, arranjados em um esquema fatorial 3x3 (níveis de salinidade x época de início da aplicação da salinidade, mais a testemunha. A salinidade da solução nutritiva produzida pelo rejeito salino reduziu, de forma significativa, a matéria fresca da parte aérea, matéria seca da parte aérea e a produção dos frutos da cultura do tomate. A época de início da aplicação do rejeito à solução nutritiva, reduziu apenas a matéria seca da parte aérea e a produção de frutos do tomateiro, quando aplicado a partir dos 7 DAT, enquanto a interação desses fatores não produziu efeito significativo para as variáveis estudadas.The objective of this study was to evaluate the response of tomato (Lycopersicon esculentum in a hydroponic system, adding water from desalination in the composition of the nutrient solution, resulting in three levels of salinity of nutrient solution: 7,1; 8,7 and 10 ,1 dS m-1, and the control (without addition of water from desalination: 2.1 dS m-1, starting its application at different stages of crop development: 7, 32 and 58 days after transplanting (DAT. The design was completely randomized with 9 treatments and 3 replications, arranged in a 3x3 factorial design (levels of salinity x starting time of the application of salinity, and control. The salinity of the nutrient solution produced by the saline water, significantly reduced the fresh weight of shoot, dry

  20. Confiabilidade de instrumentos diagnósticos: estudo do inventário de sintomas psiquiátricos do DSM-III aplicado em amostra populacional Reliability of diagnostic instruments: investigating the psychiatric DSM-III checklist applied to community samples

    Directory of Open Access Journals (Sweden)

    Sérgio Baxter Andreoli

    2001-12-01

    Full Text Available O objetivo foi estudar a confiabilidade do inventário de sintomas psiquiátricos do DSM-III aplicado em amostras representativas da população geral de três cidades brasileiras. Foram utilizados os métodos do entrevistador-observador e de consistência interna para medir a confiabilidade. Os diagnósticos de ansiedade generalizada, na vida (k = 0,46, no ano (k = 1,00, depressão na vida (k = 0,77 e os diagnósticos de abuso e dependência de álcool na vida (k = 1,00 foram confiáveis de forma consistente nos dois métodos empregados. Os diagnósticos de agorafobia (k = 1,00, fobia simples (k = 0,77, transtorno psicótico não esquizofrênico (k = 1,00 e o de fatores psicológicos que afetam o físico (1,00, todos feitos para a vida, apresentaram confiabilidade excelente medidos por meio do Kappa. O principal problema de medir a confiabilidade em estudos populacionais é a baixa prevalência de alguns diagnósticos que resulta em uma pequena variabilidade nas respostas positivas, o que impossibilita o cálculo do Kappa. Por causa disso, apenas 11 dos 39 diagnósticos que compõem o inventário puderam ser examinados. Recomenda-se a utilização do método de teste e re-teste com um tempo curto entre as entrevistas para diminuir esse problema.This study focused on the reliability of the DSM-III inventory of psychiatric symptoms in representative general population samples in three Brazilian cities. Reliability was assessed through two different designs: inter-rater reliability and internal consistency. Diagnosis of lifetime (k = 0.46 and same-year generalized anxiety (k = 1.00, lifetime depression (k = 0.77, and lifetime alcohol abuse and dependence (k = 1.00 was consistently reliable in the two methods. Lifetime diagnosis of agoraphobia (k = 1.00, simple phobia (k = 0.77, non-schizophrenic psychosis (k = 1.00, and psychological factors affecting physical health (1.00 showed excellent reliability as measured by the kappa coefficient. The main

  1. Weak Convergence of Smoothed and Nonsmoothed Bootstrap Quantile Estimates

    OpenAIRE

    Falk, M; Reiss, R.-D.

    1989-01-01

    Under fairly general assumptions on the underlying distribution function, the bootstrap process, pertaining to the sample $q$-quantile, converges weakly in $D_\\mathbb{R}$ to the standard Brownian motion. Furthermore, weak convergence of a smoothed bootstrap quantile estimate is proved which entails that in this particular case the smoothed bootstrap estimate outperforms the nonsmoothed one.

  2. Testing for asymmetry in economic time series using bootstrap methods

    OpenAIRE

    Claudio Lupi; Patrizia Ordine

    2001-01-01

    In this paper we show that phase-scrambling bootstrap offers a natural framework for asymmetry testing in economic time series. A comparison with other bootstrap schemes is also sketched. A Monte Carlo analysis is carried out to evaluate the size and power properties of the phase-scrambling bootstrap-based test.

  3. The bootstrap current and its consequences

    International Nuclear Information System (INIS)

    The physical mechanism behind the bootstrap current is explained, and the consequences are discussed with the emphasis on the two main objectives of fusion plasma, confinement and MHD stability. For a tokamak reactor that is optimized for good confinement and stability, and that has a limited size, the total plasma current exceeds the bootstrap current by a factor of three to five and therefore almost all the plasma current must be driven through other means. Furthermore, the neoclassical tearing mode which is driven by the bootstrap current is expected to be the limiting MHD instability in these reactors. Raising the fraction of the bootstrap current is not expected to be beneficial for confinement and stability expect when broad pressure profiles (internal transport barriers) can be realized. In stellarators several optimizations are possible, either optimizing the current to zero such that it does not destroy the desired topology, and it does not generate any current-driven instabilities, or using the current to generate some of the poloidal field. (author)

  4. How to Bootstrap a Human Communication System

    Science.gov (United States)

    Fay, Nicolas; Arbib, Michael; Garrod, Simon

    2013-01-01

    How might a human communication system be bootstrapped in the absence of conventional language? We argue that motivated signs play an important role (i.e., signs that are linked to meaning by structural resemblance or by natural association). An experimental study is then reported in which participants try to communicate a range of pre-specified…

  5. Bootstrapping Density-Weighted Average Derivatives

    DEFF Research Database (Denmark)

    Cattaneo, Matias D.; Crump, Richard K.; Jansson, Michael

    Employing the "small bandwidth" asymptotic framework of Cattaneo, Crump, and Jansson (2009), this paper studies the properties of a variety of bootstrap-based inference procedures associated with the kernel-based density-weighted averaged derivative estimator proposed by Powell, Stock, and Stoker...

  6. Pulling Econometrics Students up by Their Bootstraps

    Science.gov (United States)

    O'Hara, Michael E.

    2014-01-01

    Although the concept of the sampling distribution is at the core of much of what we do in econometrics, it is a concept that is often difficult for students to grasp. The thought process behind bootstrapping provides a way for students to conceptualize the sampling distribution in a way that is intuitive and visual. However, teaching students to…

  7. A Bootstrap Procedure of Propensity Score Estimation

    Science.gov (United States)

    Bai, Haiyan

    2013-01-01

    Propensity score estimation plays a fundamental role in propensity score matching for reducing group selection bias in observational data. To increase the accuracy of propensity score estimation, the author developed a bootstrap propensity score. The commonly used propensity score matching methods: nearest neighbor matching, caliper matching, and…

  8. Automatic bootstrapping and tracking of object contours.

    Science.gov (United States)

    Chiverton, John; Xie, Xianghua; Mirmehdi, Majid

    2012-03-01

    A new fully automatic object tracking and segmentation framework is proposed. The framework consists of a motion-based bootstrapping algorithm concurrent to a shape-based active contour. The shape-based active contour uses finite shape memory that is automatically and continuously built from both the bootstrap process and the active-contour object tracker. A scheme is proposed to ensure that the finite shape memory is continuously updated but forgets unnecessary information. Two new ways of automatically extracting shape information from image data given a region of interest are also proposed. Results demonstrate that the bootstrapping stage provides important motion and shape information to the object tracker. This information is found to be essential for good (fully automatic) initialization of the active contour. Further results also demonstrate convergence properties of the content of the finite shape memory and similar object tracking performance in comparison with an object tracker with unlimited shape memory. Tests with an active contour using a fixed-shape prior also demonstrate superior performance for the proposed bootstrapped finite-shape-memory framework and similar performance when compared with a recently proposed active contour that uses an alternative online learning model. PMID:21908256

  9. Seletividade da soja transgênica tolerante ao glyphosate e eficácia de controle de Commelina benghalensis com herbicidas aplicados isolados e em misturas Selectivity of glyphosate-tolerant soybean and efficiency of Commelina benghalensis control using isolated and mixed herbicides

    Directory of Open Access Journals (Sweden)

    Núbia Maria Correia

    2008-01-01

    Full Text Available O objetivo do trabalho foi avaliar os possíveis efeitos fitotóxicos de herbicidas aplicados em pós-emergência, isolados e em misturas, na soja transgênica (cv. M-SOY 8008 RR tolerante ao glyphosate e no controle de plântulas de Commelina benghalensis. Os experimentos foram desenvolvidos no período de janeiro a maio de 2006, em vasos, mantidos em condições de ambiente não controlado, no Departamento de Fitossanidade, UNESP, Campus de Jaboticabal (SP. Os tratamentos avaliados foram: glyphosate (1,20 kg ha-1 e.a., chlorimuron-ethyl (0,02 kg ha-1, lactofen (0,18 kg ha-1, fomesafen (0,25 kg ha-1, flumioxazin (0,025 kg ha-1, imazethapyr (0,10 kg ha-1, chlorimuron-ethyl (0,01 kg ha-1 mais lactofen (0,096 kg ha-1, chlorimuron-ethyl (0,01 kg ha-1 mais fomesafen (0,125 kg ha-1, lactofen (0,096kg ha-1 mais fomesafen (0,125 kg ha-1, as misturas de glyphosate (0,60kgha-1 com chlorimuron-ethyl (0,01 kg ha-1, lactofen (0,096 kg ha-1, fomesafen (0,125 kg ha-1, flumioxazin (0,0125 kg ha-1, imazethapyr (0,05 kg ha-1 e uma testemunha sem aplicação de herbicida. No experimento com C. benghalensis, testou-se também a aplicação seqüencial de glyphosate (0,96 mais 0,72 kg ha-1 e.a.. A associação de ghyphosate a herbicidas utilizados em soja convencional ocasionou danos visuais às plantas de soja. Em alguns casos, como nas misturas de glyphosate com lactofen e glyphosate com flumioxazin, os sintomas foram severos, com necroses e pontos cloróticos nas folhas. Mesmo assim, essa fitointoxicação não influenciou no desenvolvimento vegetativo e reprodutivo da soja. A mistura de glyphosate a outros herbicidas, assim como a sua aplicação seqüencial, não foram eficazes no controle de C. benghalensis, nas doses testadas e quando as plantas estavam no estádio de 4 a 6 folhas totalmente expandidas.The objective of this study was to evaluate phytotoxicity effects of herbicides applied during post-emergence, either alone or in mixture with other chemicals

  10. The cluster bootstrap consistency in generalized estimating equations

    KAUST Repository

    Cheng, Guang

    2013-03-01

    The cluster bootstrap resamples clusters or subjects instead of individual observations in order to preserve the dependence within each cluster or subject. In this paper, we provide a theoretical justification of using the cluster bootstrap for the inferences of the generalized estimating equations (GEE) for clustered/longitudinal data. Under the general exchangeable bootstrap weights, we show that the cluster bootstrap yields a consistent approximation of the distribution of the regression estimate, and a consistent approximation of the confidence sets. We also show that a computationally more efficient one-step version of the cluster bootstrap provides asymptotically equivalent inference. © 2012.

  11. Iterated smoothed bootstrap confidence intervals for population quantiles

    OpenAIRE

    Lee, SMS; Ho, YHS

    2005-01-01

    This paper investigates the effects of smoothed bootstrap iterations on coverage probabilities of smoothed bootstrap and bootstrap-t confidence intervals for population quantiles, and establishes the optimal kernel bandwidths at various stages of the smoothing procedures. The conventional smoothed bootstrap and bootstrap-t methods have been known to yield one-sided coverage errors of orders O(n−1/2) and o(n−2/3), respectively, for intervals based on the sample quantile of a random sample of s...

  12. The Block-block Bootstrap: Improved Asymptotic Refinements

    OpenAIRE

    Donald W.K. Andrews

    2002-01-01

    The asymptotic refinements attributable to the block bootstrap for time series are not as large as those of the nonparametric iid bootstrap or the parametric bootstrap. One reason is that the independence between the blocks in the block bootstrap sample does not mimic the dependence structure of the original sample. This is the join-point problem. In this paper, we propose a method of solving this problem. The idea is not to alter the block bootstrap. Instead, we alter the original sample sta...

  13. A comparison of four different block bootstrap methods

    Directory of Open Access Journals (Sweden)

    Boris Radovanov

    2014-12-01

    Full Text Available The paper contains a description of four different block bootstrap methods, i.e., non-overlapping block bootstrap, overlapping block bootstrap (moving block bootstrap, stationary block bootstrap and subsampling. Furthermore, the basic goal of this paper is to quantify relative efficiency of each mentioned block bootstrap procedure and then to compare those methods. To achieve the goal, we measure mean square errors of estimation variance returns. The returns are calculated from 1250 daily observations of Serbian stock market index values BELEX15 from April 2009 to April 2014. Thereby, considering the effects of potential changes in decisions according to variations in the sample length and purposes of the use, this paper introduces stability analysis which contains robustness testing of the different sample size and the different block length. Testing results indicate some changes in bootstrap method efficiencies when altering the sample size or the block length.

  14. Bootstrapping phylogenies inferred from rearrangement data

    Directory of Open Access Journals (Sweden)

    Lin Yu

    2012-08-01

    Full Text Available Abstract Background Large-scale sequencing of genomes has enabled the inference of phylogenies based on the evolution of genomic architecture, under such events as rearrangements, duplications, and losses. Many evolutionary models and associated algorithms have been designed over the last few years and have found use in comparative genomics and phylogenetic inference. However, the assessment of phylogenies built from such data has not been properly addressed to date. The standard method used in sequence-based phylogenetic inference is the bootstrap, but it relies on a large number of homologous characters that can be resampled; yet in the case of rearrangements, the entire genome is a single character. Alternatives such as the jackknife suffer from the same problem, while likelihood tests cannot be applied in the absence of well established probabilistic models. Results We present a new approach to the assessment of distance-based phylogenetic inference from whole-genome data; our approach combines features of the jackknife and the bootstrap and remains nonparametric. For each feature of our method, we give an equivalent feature in the sequence-based framework; we also present the results of extensive experimental testing, in both sequence-based and genome-based frameworks. Through the feature-by-feature comparison and the experimental results, we show that our bootstrapping approach is on par with the classic phylogenetic bootstrap used in sequence-based reconstruction, and we establish the clear superiority of the classic bootstrap for sequence data and of our corresponding new approach for rearrangement data over proposed variants. Finally, we test our approach on a small dataset of mammalian genomes, verifying that the support values match current thinking about the respective branches. Conclusions Our method is the first to provide a standard of assessment to match that of the classic phylogenetic bootstrap for aligned sequences. Its

  15. Consistency of the jackknife-after-bootstrap variance estimator for the bootstrap quantiles of a Studentized statistic

    OpenAIRE

    Lahiri, S. N.

    2005-01-01

    Efron [J. Roy. Statist. Soc. Ser. B 54 (1992) 83--111] proposed a computationally efficient method, called the jackknife-after-bootstrap, for estimating the variance of a bootstrap estimator for independent data. For dependent data, a version of the jackknife-after-bootstrap method has been recently proposed by Lahiri [Econometric Theory 18 (2002) 79--98]. In this paper it is shown that the jackknife-after-bootstrap estimators of the variance of a bootstrap quantile are consistent for both de...

  16. Bootstrapping ${\\mathcal N}=2$ chiral correlators

    CERN Document Server

    Lemos, Madalena

    2016-01-01

    We apply the numerical bootstrap program to chiral operators in four-dimensional ${\\mathcal N}=2$ SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of ${\\mathcal N}=2$ SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  17. Extremal bootstrapping: go with the flow

    CERN Document Server

    El-Showk, Sheer

    2016-01-01

    The extremal functional method determines approximate solutions to the constraints of crossing symmetry, which saturate bounds on the space of unitary CFTs. We show that such solutions are characterized by extremality conditions, which may be used to flow continuously along the boundaries of parameter space. Along the flow there is generically no further need for optimization, which dramatically reduces computational requirements, bringing calculations from the realm of computing clusters to laptops. Conceptually, extremality sheds light on possible ways to bootstrap without positivity, extending the method to non-unitary theories, and implies that theories saturating bounds, and especially those sitting at kinks, have unusually sparse spectra. We discuss several applications, including the first high-precision bootstrap of a non-unitary CFT.

  18. The $(2,0)$ superconformal bootstrap

    CERN Document Server

    Beem, Christopher; Rastelli, Leonardo; van Rees, Balt C

    2016-01-01

    We develop the conformal bootstrap program for six-dimensional conformal field theories with $(2,0)$ supersymmetry, focusing on the universal four-point function of stress tensor multiplets. We review the solution of the superconformal Ward identities and describe the superconformal block decomposition of this correlator. We apply numerical bootstrap techniques to derive bounds on OPE coefficients and scaling dimensions from the constraints of crossing symmetry and unitarity. We also derive analytic results for the large spin spectrum using the lightcone expansion of the crossing equation. Our principal result is strong evidence that the $A_1$ theory realizes the minimal allowed central charge $(c=25)$ for any interacting $(2,0)$ theory. This implies that the full stress tensor four-point function of the $A_1$ theory is the unique unitary solution to the crossing symmetry equation at $c=25$. For this theory, we estimate the scaling dimensions of the lightest unprotected operators appearing in the stress tenso...

  19. Bootstrapped models for intrinsic random functions

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, K.

    1987-01-01

    The use of intrinsic random function stochastic models as a basis for estimation in geostatistical work requires the identification of the generalized covariance function of the underlying process, and the fact that this function has to be estimated from the data introduces an additional source of error into predictions based on the model. This paper develops the sample reuse procedure called the ''bootstrap'' in the context of intrinsic random functions to obtain realistic estimates of these errors. Simulation results support the conclusion that bootstrap distributions of functionals of the process, as well as of their ''kriging variance,'' provide a reasonable picture of the variability introduced by imperfect estimation of the generalized covariance function.

  20. Desempenho de um reator Fenton em escala industrial aplicado à remoção de fenóis em uma planta de recuperação de resíduos da indústria de papel e celulose

    Directory of Open Access Journals (Sweden)

    Everton Skoronski

    2015-11-01

    Full Text Available Este trabalho descreve o desempenho de um reator Fenton em grande escala usado para remoção de fenol em uma planta de valorização dos resíduos da indústria de papel e celulose. O efluente consiste em óleo vegetal e fenol. A estação de tratamento objetiva tratar 4 m3 h-1 e é constituída por um pré-tratamento para remoção de óleo, reator Fenton, Flotador de Ar Dissolvido - FAD e uma lagoa de aeração. Para a avaliação da estação de tratamento foram comparadas análises próprias do efluente com análises feitas em laboratório certificado. A eficiência global de remoção de fenol é maior do que 99,7%. Foi demonstrado que a combinação do processo de oxidação avançada com o biológico constitui-se em um sistema de tratamentos interessante a fim de remover contaminantes recalcitrantes.

  1. The Correct Kriging Variance Estimated by Bootstrapping

    OpenAIRE

    den Hertog, D.; Kleijnen, J.P.C.; Siem, A.Y.D.

    2004-01-01

    The classic Kriging variance formula is widely used in geostatistics and in the design and analysis of computer experiments.This paper proves that this formula is wrong.Furthermore, it shows that the formula underestimates the Kriging variance in expectation.The paper develops parametric bootstrapping to estimate the Kriging variance.The new method is tested on several artificial examples and a real-life case study.These results demonstrate that the classic formula underestimates the true Kri...

  2. TASI Lectures on the Conformal Bootstrap

    CERN Document Server

    Simmons-Duffin, David

    2016-01-01

    These notes are from courses given at TASI and the Advanced Strings School in summer 2015. Starting from principles of quantum field theory and the assumption of a traceless stress tensor, we develop the basics of conformal field theory, including conformal Ward identities, radial quantization, reflection positivity, the operator product expansion, and conformal blocks. We end with an introduction to numerical bootstrap methods, focusing on the 2d and 3d Ising models.

  3. Bootstrapping Deep Lexical Resources: Resources for Courses

    CERN Document Server

    Baldwin, Timothy

    2007-01-01

    We propose a range of deep lexical acquisition methods which make use of morphological, syntactic and ontological language resources to model word similarity and bootstrap from a seed lexicon. The different methods are deployed in learning lexical items for a precision grammar, and shown to each have strengths and weaknesses over different word classes. A particular focus of this paper is the relative accessibility of different language resource types, and predicted ``bang for the buck'' associated with each in deep lexical acquisition applications.

  4. Bootstraping the general linear hypothesis test

    OpenAIRE

    Delicado, Pedro; Río, Manuel del, 1690-1766

    1993-01-01

    We discuss the use of bootstrap methodology in hypothesis testing, focusing on the classical F-test for linear hypotheses in the linear model. A modification of the F-statistics which allows for resampling under the null hypothesis is proposed. This approach is specifically considered in the one-way analysis of variance model. A simulation study illustrating the behaviour of our proposal is presented.

  5. Accidental symmetries and the conformal bootstrap

    Science.gov (United States)

    Chester, Shai M.; Giombi, Simone; Iliesiu, Luca V.; Klebanov, Igor R.; Pufu, Silviu S.; Yacoby, Ran

    2016-01-01

    We study an N=2 supersymmetric generalization of the three-dimensional critical O( N) vector model that is described by N + 1 chiral superfields with superpotential W = g 1 X∑ i Z 1 2 + g 2 X 3. By combining the tools of the conformal bootstrap with results obtained through supersymmetric localization, we argue that this model exhibits a symmetry enhancement at the infrared superconformal fixed point due to g 2 flowing to zero. This example is special in that the existence of an infrared fixed point with g 1 , g 2 ≠ 0, which does not exhibit symmetry enhancement, does not generally lead to any obvious unitarity violations or other inconsistencies. We do show, however, that the F-theorem excludes the models with g 1 , g 2 ≠ 0 for N > 5. The conformal bootstrap provides a stronger constraint and excludes such models for N > 2. We provide evidence that the g 2 = 0 models, which have the enhanced O( N) × U(1) symmetry, come close to saturating the bootstrap bounds. We extend our analysis to fractional dimensions where we can motivate the nonexistence of the g 1 , g 2 ≠ 0 models by studying them perturbatively in the 4 - ɛ expansion.

  6. Caracterização de tubo e adesivo utilizados em tubulações de plástico reforçado com fibras de vidro aplicados em plataformas marítimas Characterization of pipes and adhesives of glassfiber reinforced plastics used in offshore platforms

    OpenAIRE

    Maikon C. R. Pessanha; Dylmar P. Dias; Marcello Filgueira; Ronaldo P. R. Paranhos; Otávio L. de Farias

    2008-01-01

    Na indústria de exploração e produção de petróleo, principalmente no setor offshore, os plásticos reforçados por fibras de vidro (PRFV) têm apresentado grande destaque. Isso se deve à intrínseca capacidade destes de resistir à corrosão em ambientes salinos, bem como serem materiais que apresentam elevada resistência mecânica específica. O presente trabalho buscou caracterizar tubo e adesivo utilizados em plataformas marítimas. Para tanto, as técnicas utilizadas foram: espectroscopia na região...

  7. Seletividade de herbicidas aplicados nas gramas Santo Agostinho e Esmeralda Selectivity of herbicides applied on St. Augustinegrass and Emerald turfs

    OpenAIRE

    N.V. Costa; Martins, D; A.C.P. Rodrigues; L.A. Cardoso

    2010-01-01

    Objetivou-se neste trabalho avaliar a seletividade de herbicidas aplicados nas gramas Santo Agostinho (Stenotaphrum secundatum) e Esmeralda (Zoysia japonica) em condições de campo. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições. As gramas foram cortadas a 3 cm de altura e, em seguida, foram feitas as aplicações dos herbicidas. Os tratamentos utilizados foram: testemunha sem aplicação, fluazifop-p-butil (125 g ha-1), sethoxydim+óleo mineral (276 g ha-...

  8. Bootstrap determination of the cointegration rank in heteroskedastic VAR models

    DEFF Research Database (Denmark)

    Cavaliere, Guiseppe; Rahbæk, Anders; Taylor, A.M. Robert

    2014-01-01

    In a recent paper Cavaliere et al. (2012) develop bootstrap implementations of the (pseudo-) likelihood ratio (PLR) co-integration rank test and associated sequential rank determination procedure of Johansen (1996). The bootstrap samples are constructed using the restricted parameter estimates of...... the underlying vector autoregressive (VAR) model which obtain under the reduced rank null hypothesis. They propose methods based on an independent and individual distributed (i.i.d.) bootstrap resampling scheme and establish the validity of their proposed bootstrap procedures in the context of a co......-integrated VAR model with i.i.d. innovations. In this paper we investigate the properties of their bootstrap procedures, together with analogous procedures based on a wild bootstrap resampling scheme, when time-varying behavior is present in either the conditional or unconditional variance of the innovations. We...

  9. Tolerância inicial de plantas de pinhão-manso a herbicidas aplicados em pré e pós-emergência Initial tolerance of physic nut plants to pre and post-emergence herbicide application

    Directory of Open Access Journals (Sweden)

    E.A.L. Erasmo

    2009-01-01

    Full Text Available O presente trabalho teve por objetivo avaliar a tolerância inicial de plantas de pinhão-manso a herbicidas pré e pós-emergentes, aplicados isolados e em misturas. Foram realizados dois experimentos em condições de campo, sendo um com herbicidas pré-emergentes e outro com herbicidas pós-emergentes. Os tratamentos com os herbicidas pré-emergentes utilizados foram: atrazine (3.000 g ha-1, diuron (2.000 g ha-1, oxyfluorfen (720 g ha-1, trifluralin (890 g ha-1, pendimethalin (1.250 g ha-1, isoxaflutole (93,8 g ha-1, S-metolachlor (1.920 g ha-1, atrazine+S-metolachlor (1.500+960 g ha-1, isoxaflutole+diuron (46,9+1.000 g ha-1, trifluralin+diuron (450+1.000 g ha-1, além de uma testemunha sem aplicação. Os tratamentos com os herbicidas pós-emergentes foram: haloxyfop-methyl (60 g ha-1, nicosulfuron (60 g ha-1, sethoxydim (368 g ha-1, fluazifop-p-butyl (125 g ha-1, fluazifop-p-butyl (250 g ha-1, fomesafen (125 g ha-1, fomesafen (250 g ha-1, fluazifop-p-butyl+fomesafen (250+250 g ha-1, fluazifop-p-butyl+fomesafen (200+250 g ha ¹, clethodim + fenoxaprop-p-ethyl (50+50 g ha-1, além de uma testemunha sem aplicação e outra capinada. Os tratamentos foram dispostos em delineamento experimental de blocos casualizados, com quatro repetições. No experimento com herbicidas pré-emergentes verificou-se que plantas de pinhão-manso foram tolerantes ao diuron, trifluralin, pendimethalin, isoxaflutole, S-metolachlor e às misturas isoxaflutole+diuron e trifluralin+diuron. Com relação ao experimento com herbicidas pós-emergentes, destacaram-se o haloxyfop-methyl, sethoxydim, fluazifop-p-butyl (125 g ha-1 e a mistura clethodim+fenoxaprop-p-ethyl.This study aimed to evaluate the initial tolerance of physic nut plants to pre and post-emergence herbicides, applied alone and in mixtures. Thus, two experiments were conducted under field conditions, one with pre-emergence herbicides and the other with post-emergence herbicides. The treatments using the pre

  10. Stationary bootstrapping realized volatility under market microstructure noise

    OpenAIRE

    Hwang, Eunju; Shin, Dong Wan

    2013-01-01

    Large-sample validity is proved for stationary bootstrapping of a bias-corrected realized volatility under market microstructure noise, which enables us to construct a bootstrap confidence interval of integrated volatility. A finite-sample simulation shows that the stationary bootstrapping confidence interval outperforms existing ones which are constructed ignoring market microstructure noise or using asymptotic normality for the bias-corrected realized volatility.

  11. Model Based Bootstrap Methods for Interval Censored Data

    OpenAIRE

    Sen, Bodhisattva; Xu, Gongjun

    2013-01-01

    We investigate the performance of model based bootstrap methods for constructing point-wise confidence intervals around the survival function with interval censored data. We show that bootstrapping from the nonparametric maximum likelihood estimator of the survival function is inconsistent for both the current status and case 2 interval censoring models. A model based smoothed bootstrap procedure is proposed and shown to be consistent. In addition, simulation studies are conducted to illustra...

  12. Change-point in stochastic design regression and the bootstrap

    OpenAIRE

    Seijo, Emilio; Sen, Bodhisattva

    2011-01-01

    In this paper we study the consistency of different bootstrap procedures for constructing confidence intervals (CIs) for the unique jump discontinuity (change-point) in an otherwise smooth regression function in a stochastic design setting. This problem exhibits nonstandard asymptotics and we argue that the standard bootstrap procedures in regression fail to provide valid confidence intervals for the change-point. We propose a version of smoothed bootstrap, illustrate its remarkable finite sa...

  13. Is Bootstrap Really Helpful in Point Process Statistics?

    OpenAIRE

    Snethlage, Martin

    2000-01-01

    There are some papers which describe the use of bootstrap techniques in point process statistics. The aim of the present paper is to show that the form in which bootstrap is used there is dubious. In case of variance estimation of pair correlation function estimators the used bootstrap techniques lead to results which can be obtained simpler without simulation; furthermore, they differ from the desired results. The problem to obtain confidence regions for the intensity function of inhomogeneo...

  14. A PARAMETRIC BOOTSTRAP USING THE FIRST FOURMOMENTS OF THE RESIDUALS

    OpenAIRE

    Pierre-Eric Treyens

    2007-01-01

    We consider linear regression models and we suppose that disturbances are either Gaussian or non Gaussian. Until now, within the framework of the bootstrap, we thought that the error in rejection probability (ERP) had the same rate of convergence with the parametric bootstrap or the nonparametric bootstrap. For linear data generating processes (DGP) we show in this paper that this assertion is false if skewness and/or kurtosis coefficients of the distribution of the disturbances are nonnull. ...

  15. Improving Coverage Accuracy of Block Bootstrap Confidence Intervals

    OpenAIRE

    Lee, Stephen M. S.; Lai, P. Y.

    2008-01-01

    The block bootstrap confidence interval based on dependent data can outperform the computationally more convenient normal approximation only with non-trivial Studentization which, in the case of complicated statistics, calls for highly specialist treatment. We propose two different approaches to improving the accuracy of the block bootstrap confidence interval under very general conditions. The first calibrates the coverage level by iterating the block bootstrap. The second calculates Student...

  16. Bootstrap confidence intervals for the process capability index under half-logistic distribution

    OpenAIRE

    Wararit Panichkitkosolkul

    2012-01-01

    This study concerns the construction of bootstrap confidence intervals for theprocess capability index in the case of half-logistic distribution. The bootstrap confidence intervals applied consist of standard bootstrap confidence interval, percentile bootstrap confidence interval and bias-corrected percentile bootstrap confidence interval. Using Monte Carlo simulations, the estimated coverage probabilities and average widths ofbootstrap confidence intervals are compared, with results showing ...

  17. Atividade residual de herbicidas aplicados em pós-emergência na cultura da soja sobre o milheto cultivado em sucessão Effect of the residual activity of herbicides applied in post-emergence soybean on pearl millet grown in succession

    Directory of Open Access Journals (Sweden)

    H.A Dan

    2011-09-01

    Full Text Available O objetivo deste trabalho foi avaliar a atividade residual de herbicidas utilizados em pós-emergência da cultura da soja sobre o milheto cultivado em sucessão. O experimento foi realizado em Latossolo Vermelho distroférrico de textura argilosa em região de cerrado. Os herbicidas chlorimuron-ethyl (0,015 kg ha-1, imazethapyr (0,060 kg ha-1, imazethapyr (0,100 kg ha-1 e fomesafen (0,250 kg ha-1 foram utilizados em pós-emergência do cultivar de soja Msoy-6101. Utilizou-se o delineamento de blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas (5 x 4. Nas subparcelas, realizou-se a semeadura do milheto (híbrido ADR-7010 em quatro períodos, correspondendo a 0, 40, 80 e 120 dias após a aplicação dos herbicidas (DAA. Durante a condução do ensaio, avaliou-se a intoxicação da cultura aos 7 e 28 dias após a emergência, o estande, a altura e a matéria seca da parte aérea das plantas de milheto. Ao final do ciclo da cultura, determinou-se o rendimento de grãos. O imazethapyr (0,060 kg ha-1 e chlorimuron-ethyl (0,015 kg ha-1 não alteraram significativamente o rendimento da cultura do milheto em semeaduras posteriores a 80 DAA. Para fomesafen, o intervalo mínimo de segurança entre a aplicação e a semeadura do milheto foi de 100 dias. Por outro lado, maior persistência foi observada para imazethapyr na dose 0,100 kg ha-1, chegando a 120 dias de bioatividade sobre o milheto, que teve seu rendimento de grãos alterando mesmo quando semeado durante esse período.The objective of this study was to evaluate the residual activity of herbicides used in post-emergence soybean on Pearl Millet grown in succession. The experiment was conducted in clay soil in cerrado region. The herbicides chlorimuron-ethyl (0.015 kg ha-1, imazethapyr (0.060 kg ha-1, imazethapyr (0.100 kg ha-1 and fomesafen (0.250 kg ha-1 were used in post-emergence soybean cultivar Msoy-6101, in plots of 80 m² that were subdivided into sub-plots of

  18. Bootstrap current fraction scaling for a tokamak reactor design study

    International Nuclear Information System (INIS)

    Highlights: • New bootstrap current fraction scalings for systems codes were derived by solving the Hirshman–Sigmar model. • Nine self-consistent MHD equilibria were constructed in order to compare the bootstrap current fraction values. • Wilson formula most successfully predicted the bootstrap current fraction, but it requires current density profile index. • The new scaling formulas and IPDG accurately estimated the fBS values for the normal and weakly reversed shear tokamaks. - Abstract: We have derived new bootstrap current fraction scalings for systems codes by solving the Hirshman–Sigmar model, which is valid for arbitrary aspect ratios and collision conditions. The bootstrap current density calculation module in the ACCOME code was used with the matrix inversion method without the large aspect ratio assumption. Nine self-consistent MHD equilibria, which cover conventional, advanced and spherical tokamaks with normal or reversed shear, were constructed using numerical calculations in order to compare the bootstrap current fraction values with those of the new model and all six existing models. The Wilson formula successfully predicted the bootstrap current fraction, but it requires current density profile index for the calculation. The new scaling formulas and IPDG accurately estimated the bootstrap current fraction for the normal and weakly reversed shear tokamaks, regardless of the aspect ratio. However, none of the existing models except the Wilson formula can accurately estimate the bootstrap current fraction for the reversed shear tokamaks, which is promising for the advanced tokamak operation mode

  19. Metastability threshold for anisotropic bootstrap percolation in three dimensions

    CERN Document Server

    van Enter, Aernout

    2011-01-01

    In this paper we analyze several anisotropic bootstrap percolation models in three dimensions. We present the order of magnitude for the metastability threshold for a fairly general class of models. In our proofs we use an adaptation of the technique of dimensional reduction. We find that the order of the metastability threshold is generally determined by the "easiest growth direction" in the model. In contrast to the anisotropic bootstrap percolation in two dimensions, in three dimensions the order of the metatstability threshold for anisotropic bootstrap percolation can be equal to that of isotropic bootstrap percolation.

  20. Confidence Intervals for the Mean: To Bootstrap or Not to Bootstrap

    Science.gov (United States)

    Calzada, Maria E.; Gardner, Holly

    2011-01-01

    The results of a simulation conducted by a research team involving undergraduate and high school students indicate that when data is symmetric the student's "t" confidence interval for a mean is superior to the studied non-parametric bootstrap confidence intervals. When data is skewed and for sample sizes n greater than or equal to 10, the results…

  1. A bootstrap approach to bump hunting

    Science.gov (United States)

    Silverman, B. W.

    1982-01-01

    An important question in cluster analysis and pattern recognition is the determination of the number of clusters into which a given population should be divided. Frequently, particularly when certain specific clustering methods are being used, the number of clusters is taken to be equal to the number of modes, or local maxima, in the probability density function underlying the given data set. The use of kernal density estimates in mode estimation is discussed. The test statistic to be used is defined and a bootstrap technique for assessing significance is given. An illustrative application is followed by an examination of the asymptotic behavior of the test statistic.

  2. Evaluating Neural Network Predictors by Bootstrapping

    OpenAIRE

    Blake LeBaron; Andreas S. Weigend

    1994-01-01

    We present a new method, inspired by the bootstrap, whose goal it is to determine the quality and reliability of a neural network predictor. Our method leads to more robust forecasting along with a large amount of statistical information on forecast performance that we exploit. We exhibit the method in the context of multi-variate time series prediction on financial data from the New York Stock Exchange. It turns out that the variation due to different resamplings (i.e., splits between traini...

  3. High βp bootstrap tokamak reactor

    International Nuclear Information System (INIS)

    Basic characteristics of a steady state tokamak fusion reactor is presented. The minimum required energy multiplication factor Q is found to be 20 to 30 for the feasibility of the fusion reactor. Such a high Q steady state tokamak operation is possible, within our present knowledge of the operational constraints and the current drive physics, when a large fraction of the plasma current is carried by the bootstrap current. Operation at high βp (≥2.0) and high qψ (=4-5) with relatively small εβp (3) and fusion output power (2.5 GW) and is consistent with the present knowledges of the plasma physics of the tokamak, namely the Troyon limit, the energy confinement scalings, the bootstrap current, the current drive efficiency (NB current drive with the total power of 70 MW and the beam energy of 1 MeV) with a favorable aspect on the formation of the cold and dense diverter plasma-condition. From the economical aspect of the tokamak fusion reactor, a more compact reactor is favorable. The use of the high field magnet with Bmax = 16T (for example Ti-doped Nb3Sn conductor) enables to reduce the total machine size to 50% of the above-described conventional design, namely Rp = 7m, Vp = 760m-3, PF = 2.8 GW. (author)

  4. Physics issues of high bootstrap current tokamaks

    International Nuclear Information System (INIS)

    Physics issues of a tokamak plasma with a hollow current profile produced by a large bootstrap current are discussed based on experiments in JT-60U. An internal transport barrier for both ions and electrons was obtained just inside the radius of zero magnetic shear in JT-60U. Analysis of the toroidal ITG microinstability by toroidal particle simulation shows that weak and negative shear reduces the toroidal coupling and suppresses the ITG mode. A hard beta limit was observed in JT-60U negative shear experiments. Ideal MHD mode analysis shows that the n = 1 pressure-driven kink mode is a plausible candidate. One of the methods to improve the beta limit against the kink mode is to widen the negative shear region, which can induce a broader pressure profile resulting in a higher beta limit. The TAE mode for the hollow current profile is less unstable than that for the monotonic current profile. The reason is that the continuum gaps near the zero shear region are not aligned when the radius of qmin is close to the region of high ∇ne. Finally, a method for stable start-up for a plasma with a hollow current profile is describe, and stable sustainment of a steady-state plasma with high bootstrap current is discussed. (Author)

  5. Impacto de un programa de promoción de la salud aplicado por enfermería a pacientes diabéticos tipo 2 en la comunidad Impacto de um programa de promoção da saúde aplicado pela enfermagem em pacientes diabéticos tipo 2, na comunidade Impact of a health promotion program carried out by nursing among type 2 diabetes patients,within the community

    Directory of Open Access Journals (Sweden)

    Liudmila Otero Miyar

    2003-12-01

    Full Text Available Estudio cuasiexperimental que tuvo como objetivo medir el impacto de un programa de promoción de la salud sobre el conocimiento acerca de la diabetes mellitus en la población diabética tipo 2 de Querétaro, México, en el año 2001. Se realizó una intervención de enfermería en 40 pacientes que aceptaron participar en el estudio mediante la firma del consentimiento informado. Se aplicó un cuestionario, antes y después de la intervención para medir el conocimiento alcanzado sobre la enfermedad. Para el análisis de los datos se utilizaron como medidas de las variables cualitativas el porciento y los números absolutos y como prueba de significación ji² siendo alfa=0.05. Después de la intervención, el porcentaje de pacientes con conocimientos sobre la enfermedad se elevó de 10% a 72.5%. Con el programa implementado se logró elevar el nivel de conocimiento sobre diabetes mellitus.Estudo quase experimental que teve como objetivo medir o impacto de um programa de promoção da saúde sobre o conhecimento em diabetes mellitus na população diabética tipo 2, de Querétaro, México, no ano 2001. Realizou-se uma intervenção de enfermagem em 40 pacientes, que aceitaram participar do estudo mediante consentimento informado. Aplicou-se um questionário, antes e após a intervenção, para medir o conhecimento alcançado sobre a doença. Para análise dos dados, utilizou-se como medidas de variáveis qualitativas a percentagem e os números absolutos; para teste de significância utilizou-se chi², sendo alfa=0,05. Após a intervenção os conhecimentos sobre a doença elevaram-se de 10% para 72,5%. Com o programa implementado conseguiu-se elevar o nível de conhecimento sobre a diabetes mellitus.The goal of this quasi-experimental study was to measure the impact of a health promotion program on the knowledge of the type 2 diabetic population in Querétaro, Mexico about diabetes mellitus type 2. A nursing intervention was carried out with

  6. On the Bootstrap of $U$ and $V$ Statistics

    OpenAIRE

    Arcones, Miguel A.; Gine, Evarist

    1992-01-01

    Bootstrap distributional limit theorems for $U$ and $V$ statistics are proved. They hold a.s., under weak moment conditions and without restrictions on the bootstrap sample size (as long as it tends to $\\infty$), regardless of the degree of degeneracy of $U$ and $V$. A testing procedure based on these results is outlined.

  7. MHD equilibrium property with bootstrap current in heliotron plasmas

    International Nuclear Information System (INIS)

    We study the properties of MHD equilibrium with self-consistent bootstrap current for a heliotron type device. We show the possibility that MHD equilibrium beta limit with consistent bootstrap current might significantly decrease in the low collisional regime comparing with currentless case depending on the vertical field control methods in finite beta and magnetic configurations. (author)

  8. Discharges with high bootstrap current fraction on Tore Supra

    International Nuclear Information System (INIS)

    This document deals with bootstrap current non-inductively driving a fraction of the total current. Non-inductive current density profile is determined on Tore Supra and high bootstrap current fraction regimes in Tore Supra are analysed. (TEC). 11 refs., 3 figs

  9. FWEH induced high bootstrap current on Tore Supra

    International Nuclear Information System (INIS)

    Bootstrap current is regarded as a good candidate to sustain a large fraction of the plasma current, in the so-called open-quotes advancedclose quotes regimes of a tokamak reactor. It is thus important to study the stability of such discharges and to control them. By means of fast wave electron heating (FWEH, up to 9.5 MW), stationary high bootstrap discharges (during 5 seconds, ∼40%) were routinely obtained on Tore Supra. The bootstrap profile is computed with a matrix formulation (1,2) and is directly compared to the experimental determination of the non-inductive current. The simulation of the loop voltage either with the code CRONOS (1D current diffusion code) using the profile of bootstrap current, or with the knowledge of the resistivity, allows also a self consistent determination of the bootstrap current. The bootstrap induced by the FWEH is mainly due to the central pressure electron gradient (the central power deposition strongly peaks the electronic temperature). A 0D study shows that the bootstrap current (Ibs) varies linearly with the poloidal beta (Ibs/Ip∼Cbsβp). The effect of various plasma parameters (toroidal field Bt, line-integrated density nl, ion and electron temperature, plasma current Ip) on the bootstrap profile, and fraction are analysed. copyright 1997 American Institute of Physics

  10. On bootstrap sample size in extreme value theory

    NARCIS (Netherlands)

    J.L. Geluk (Jaap); L.F.M. de Haan (Laurens)

    2002-01-01

    textabstractIt has been known for a long time that for bootstrapping the probability distribution of the maximum of a sample consistently, the bootstrap sample size needs to be of smaller order than the original sample size. See Jun Shao and Dongsheng Tu (1995), Ex. 3.9,p. 123. We show that the same

  11. Bootstrap Estimates of Standard Errors in Generalizability Theory

    Science.gov (United States)

    Tong, Ye; Brennan, Robert L.

    2007-01-01

    Estimating standard errors of estimated variance components has long been a challenging task in generalizability theory. Researchers have speculated about the potential applicability of the bootstrap for obtaining such estimates, but they have identified problems (especially bias) in using the bootstrap. Using Brennan's bias-correcting procedures…

  12. Using Commonly Available Software for Conducting Bootstrap Analyses.

    Science.gov (United States)

    Fan, Xitao

    Bootstrap analysis, both for nonparametric statistical inference and for describing sample results stability and replicability, has been gaining prominence among quantitative researchers in educational and psychological research. Procedurally, however, it is often quite a challenge for quantitative researchers to implement bootstrap analysis in…

  13. Unbiased Estimates of Variance Components with Bootstrap Procedures

    Science.gov (United States)

    Brennan, Robert L.

    2007-01-01

    This article provides general procedures for obtaining unbiased estimates of variance components for any random-model balanced design under any bootstrap sampling plan, with the focus on designs of the type typically used in generalizability theory. The results reported here are particularly helpful when the bootstrap is used to estimate standard…

  14. Bootstrapping and Bartlett corrections in the cointegrated VAR model

    NARCIS (Netherlands)

    P.H. Omtzigt; S. Fachin

    2003-01-01

    The small sample properties of tests on long-run coefficients in cointegrated systems are still a matter of concern to applied econometricians. We compare the performance of the Bartlett correction, the bootstrap and the fast double bootstrap for tests on ccointegration parameters in the maximum lik

  15. A nonparametric hypothesis test via the Bootstrap resampling

    OpenAIRE

    Temel, Tugrul

    2011-01-01

    This paper adapts an already existing nonparametric hypothesis test to the bootstrap framework. The test utilizes the nonparametric kernel regression method to estimate a measure of distance between the models stated under the null hypothesis. The bootstraped version of the test allows to approximate errors involved in the asymptotic hypothesis test. The paper also develops a Mathematica Code for the test algorithm.

  16. Learning web development with Bootstrap and AngularJS

    CERN Document Server

    Radford, Stephen

    2015-01-01

    Whether you know a little about Bootstrap or AngularJS, or you're a complete beginner, this book will enhance your capabilities in both frameworks and you'll build a fully functional web app. A working knowledge of HTML, CSS, and JavaScript is required to fully get to grips with Bootstrap and AngularJS.

  17. Caracterização de tubo e adesivo utilizados em tubulações de plástico reforçado com fibras de vidro aplicados em plataformas marítimas Characterization of pipes and adhesives of glassfiber reinforced plastics used in offshore platforms

    Directory of Open Access Journals (Sweden)

    Maikon C. R. Pessanha

    2008-03-01

    Full Text Available Na indústria de exploração e produção de petróleo, principalmente no setor offshore, os plásticos reforçados por fibras de vidro (PRFV têm apresentado grande destaque. Isso se deve à intrínseca capacidade destes de resistir à corrosão em ambientes salinos, bem como serem materiais que apresentam elevada resistência mecânica específica. O presente trabalho buscou caracterizar tubo e adesivo utilizados em plataformas marítimas. Para tanto, as técnicas utilizadas foram: espectroscopia na região do infravermelho com transformada de Fourier (FTIR, análise termogravimétrica (TGA, análise termodinâmico-mecânica (DMTA e temperatura de amolecimento de Vicat. Amostras do tubo de PRFV e dos componentes do adesivo (denominados de A e B foram estudadas individualmente. Além disso, foram confeccionadas misturas, em massa, nas seguintes proporções: 40%A-60%B, 50%A-50%B e 60%A-40%B. Foi possível determinar a composição e a estrutura química dos materiais, além do comportamento mecânico à degradação térmica. Foi verificado que adesivo e tubo apresentaram desempenho satisfatório à temperatura ambiente quanto à degradação e à rigidez. Por outro lado, quando submetido ao calor, principalmente os adesivos, apresentaram queda brusca de desempenho.Glassfiber reinforced plastics (GFRP have been applied in the offshore industry owing to their high resistance to corrosion and high specific mechanical strength. The present work aimed at characterizing pipes and adhesives used in offshore platforms in order to evaluate the thermo-mechanical performance of these materials. The techniques used were: Fourier transform infrared spectroscopy (FTIR, thermogravimetry analysis (TGA, dynamic mechanical thermal analysis (DMTA and Vicat softening temperature. Specimens of GFRP pipe and adhesive components (referred to as A and B were evaluated individually. The adhesive samples were made in the following ratios (% weight: 40%A-60%B, 50%A-50

  18. Bootstrap current due to shear of magnetic field stochasticity

    International Nuclear Information System (INIS)

    The 'bootstrap' current is a fundamental effect in toroidal magnetic confinement. It is shown that the electron current in stochastic magnetic field causes not only anomalous electron heat transport, but also novel currents, termed 'anomalous bootstrap' in order to bring up the analogy with the well-known effect in the neoclassical theory. Due to the magnetic fluctuations an additional bootstrap current appears. Its value is proportional to the derivative of square of the magnetic fluctuations, the radial electric field and ratio of streaming velocity to thermal one for collisionless case. The obtained bootstrap current can be comparable with the Ohmic current. In the collisional case, in contrast to the collisionless case, the value of bootstrap current does not depend on the magnitude of the averaged velocity, but its direction is determined by the streaming velocity sign. (J.P.N.)

  19. Change-point in stochastic design regression and the bootstrap

    CERN Document Server

    Seijo, Emilio

    2011-01-01

    In this paper we study the consistency of different bootstrap procedures for constructing confidence intervals (CIs) for the unique jump discontinuity (change-point) in an otherwise smooth regression function in a stochastic design setting. This problem exhibits nonstandard asymptotics and we argue that the standard bootstrap procedures in regression fail to provide valid confidence intervals for the change-point. We propose a version of smoothed bootstrap, illustrate its remarkable finite sample performance in our simulation study, and prove the consistency of the procedure. The $m$ out of $n$ bootstrap procedure is also considered and shown to be consistent. We also provide sufficient conditions for any bootstrap procedure to be consistent in this scenario.

  20. Geoprocessamento aplicado na identificação e localização potencial de conflitos de uso em áreas de preservação permanente na microbacia do córrego Monte Belo, Botucatu (SP, Brasil Geo-processing in identifying and locating potential conflicts of land use in areas of permanent preservation of the Monte Belo watershed, Botucatu (SP, Brazil

    Directory of Open Access Journals (Sweden)

    Sérgio Campos

    2009-10-01

    Full Text Available Este trabalho teve como objetivo avaliar o geoprocessamento aplicado na identificação e localização potencial de conflitos de uso de 1592 ha em áreas de preservação permanentes (APPs da microbacia do Córrego Monte Belo - Botucatu (SP, Brasil (22° 45’ a 22° 48’ de latitude S e de 48° 15’ a 48° 21’ de longitude WGr. através do uso de Sistema de Informações Geográficas e de imagem de satélite digital, bandas 3, 4 e 5 do Sensor TM, do Landsat 5, da órbita 220, ponto 76, quadrante A, passagem de 23.10.2006. Os resultados permitiram constatar que 62.78% da área é ocupada com reflorestamento e 37.22% é mata, e que somente 2.65% da área vem sendo usado inadequadamente com reflorestamento.This work aimed to evaluate the potential of geo-processing in the identification and localization of potential conflicts of use over 1592ha in permanent preservation areas (APPs of the Monte Belo watershed - Botucatu (SP, Brazil (22° 45’ to 22° 48’ S and 48o 15’ to 48° 21’ W, through the use of Geographical Information Systems (GIS and digital satellite images, bands 3, 4 and 5 of Sensor TM of LANDSAT 5, of the orbit 220, point 76, quadrant A, passage of 23/10/2006. The results allowed verification that 62.78% of the area is occupied with reforestation and 37.22% is forest, and that only 2.65% of the area has been used inadequately with reforestation.

  1. A COMPARISON OF RESAMPLING TECHNIQUES WHEN PARAMETERS ARE ON A BOUNDARY: THE BOOTSTRAP, SUBSAMPLE BOOTSTRAP, AND SUBSAMPLE JACKKNIFE

    OpenAIRE

    Hilmer, Christiana E.; Holt, Matthew T.

    2000-01-01

    This paper compares the finite sample performance of subsample bootstrap and subsample jackknife techniques to the traditional bootstrap method when parameters are constrained to be on some boundary. To assess how these three methods perform in an empirical application, a negative semi-definite translog cost function is estimated using U.S. manufacturing data.

  2. Bootstrap performance profiles in stochastic algorithms assessment

    International Nuclear Information System (INIS)

    Optimization with stochastic algorithms has become a relevant research field. Due to its stochastic nature, its assessment is not straightforward and involves integrating accuracy and precision. Performance profiles for the mean do not show the trade-off between accuracy and precision, and parametric stochastic profiles require strong distributional assumptions and are limited to the mean performance for a large number of runs. In this work, bootstrap performance profiles are used to compare stochastic algorithms for different statistics. This technique allows the estimation of the sampling distribution of almost any statistic even with small samples. Multiple comparison profiles are presented for more than two algorithms. The advantages and drawbacks of each assessment methodology are discussed

  3. Conformal bootstrap, universality and gravitational scattering

    Directory of Open Access Journals (Sweden)

    Steven Jackson

    2015-12-01

    Full Text Available We use the conformal bootstrap equations to study the non-perturbative gravitational scattering between infalling and outgoing particles in the vicinity of a black hole horizon in AdS. We focus on irrational 2D CFTs with large c and only Virasoro symmetry. The scattering process is described by the matrix element of two light operators (particles between two heavy states (BTZ black holes. We find that the operator algebra in this regime is (i universal and identical to that of Liouville CFT, and (ii takes the form of an exchange algebra, specified by an R-matrix that exactly matches the scattering amplitude of 2+1 gravity. The R-matrix is given by a quantum 6j-symbol and the scattering phase by the volume of a hyperbolic tetrahedron. We comment on the relevance of our results to scrambling and the holographic reconstruction of the bulk physics near black hole horizons.

  4. On Bootstrap Percolation in Living Neural Networks

    CERN Document Server

    Amini, Hamed

    2009-01-01

    Recent experimental studies of living neural networks reveal that their global activation induced by electrical stimulation can be explained using the concept of bootstrap percolation on a directed random network. The experiment consists in activating externally an initial random fraction of the neurons and observe the process of firing until its equilibrium. The final portion of neurons that are active depends in a non linear way on the initial fraction. The main result of this paper is a theorem which enables us to find the asymptotic of final proportion of the fired neurons in the case of random directed graphs with given node degrees as the model for interacting network. This gives a rigorous mathematical proof of a phenomena observed by physicists in neural networks.

  5. Bootstrap consistency for general semiparametric M-estimation

    KAUST Repository

    Cheng, Guang

    2010-10-01

    Consider M-estimation in a semiparametric model that is characterized by a Euclidean parameter of interest and an infinite-dimensional nuisance parameter. As a general purpose approach to statistical inferences, the bootstrap has found wide applications in semiparametric M-estimation and, because of its simplicity, provides an attractive alternative to the inference approach based on the asymptotic distribution theory. The purpose of this paper is to provide theoretical justifications for the use of bootstrap as a semiparametric inferential tool. We show that, under general conditions, the bootstrap is asymptotically consistent in estimating the distribution of the M-estimate of Euclidean parameter; that is, the bootstrap distribution asymptotically imitates the distribution of the M-estimate. We also show that the bootstrap confidence set has the asymptotically correct coverage probability. These general onclusions hold, in particular, when the nuisance parameter is not estimable at root-n rate, and apply to a broad class of bootstrap methods with exchangeable ootstrap weights. This paper provides a first general theoretical study of the bootstrap in semiparametric models. © Institute of Mathematical Statistics, 2010.

  6. Properties of bootstrap tests for N-of-1 studies

    OpenAIRE

    Lin, Sharon Xiaowen; Morrison, Leanne; Smith, Peter; Hargood, Charlie; Weal, Mark; Yardley, Lucy

    2016-01-01

    N-of-1 study designs involve the collection and analysis of repeated measures data from an individual not using an intervention and using an intervention. This study explores the use of semi-parametric and parametric bootstrap tests in the analysis of N-of-1 studies under a single time series framework in the presence of autocorrelation. When the Type I error rates of bootstrap tests are compared to Wald tests, our results show that the bootstrap tests have more desirable properties. We compa...

  7. Nonparametric confidence intervals based on extreme bootstrap percentiles

    OpenAIRE

    Lee, SMS

    2000-01-01

    Monte Carlo approximation of standard bootstrap confidence intervals relies on the drawing of a large number, B say, of bootstrap resamples. Conventional choice of B is often made on the order of 1,000. While this choice may prove to be more than sufficient for some cases, it may be far from adequate for others. A new approach is suggested to construct confidence intervals based on extreme bootstrap percentiles and an adaptive choice of B. It economizes on the computational effort in a proble...

  8. Em busca de um território: Limites e perspectivas dos campos disciplinar e aplicado na visão dos diplomados em relações públicas pela UFPB / Looking for a territory: boundaries and outlooks of the theoretical and applied fields in the view of the public relations graduates by the UFPB

    Directory of Open Access Journals (Sweden)

    Josilene Ribeiro de Oliveira

    2013-12-01

    Full Text Available Este artigo discute os limites e as perspectivas para as relações públicas nos campos teórico e prático, por meio da identificação dos estágios de desenvolvimento da doutrina e do levantamento das percepções de egressos formados pe la Universidade Federal da Paraíba sobre o mercado de trabalho. A pesquisa descritivo-explicativa, desenvolvida em três etapas, compreendeu: a revisão dos pressupostos teóricos do paradigma sistêmico e da comunicação organizacional; o levantamento da opinião de 132 respostas através de questionários; o aprofundamento dos dados com a escuta direta de diplomados. Os resultados sugerem que o lugar das relações públicas está na fronteira entre a comunicação e a administração, um território contestado que obriga seus habitantes a serem flexíveis e manterem uma identidade mutante, tal qual todas as outras profissões que nasceram sob osigno da modernidade. / This paper discusses the boundaries and the outlooks in the theoretical and applied fields through of the identification of development stages of discipline and of the collect of perceptions of the public relations graduates by the Federal University of Paraíba (UFPB on professional activity. The descriptive and explicative research was developed in three steps: bibliographic revision of the systemic paradigm and of the organizational communication; opinion collect applied to 132 Public Relations Professionals through electronic survey; execution of the focal group with the graduates. The results suggests that the place of the public relations is on the border between the communication and administration, a contested territory that forces their residents to be flexible and to sustain a mutant identity, as the others professions that appeared about the modernity stamp.

  9. On a Second-Order Asymptotic Property of the Bayesian Bootstrap Mean

    OpenAIRE

    Weng, Chung-Sing

    1989-01-01

    It is shown that the Bayesian bootstrap approximation to the posterior distribution of the unknown mean (with respect to a Dirichlet process prior) is more accurate than both the standard normal approximation and the bootstrap approximation. It is also shown that the Bayesian bootstrap approximation to the sampling distribution of the sample average is not as accurate as the bootstrap approximation.

  10. Bootstrap current of fast ions in neutral beam injection heating

    International Nuclear Information System (INIS)

    The bootstrap current of fast ions produced by the neutral beam injection is investigated in a large aspect ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are figured out. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current considered, the net current density obviously decreases due to electron return current, at the same time the peak of current moves towards the centre plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the neutral beam injection but also on the ratio of the velocity of fast ions to the critical velocity: the value of net current is small for the neutral beam parallel injection but increases multipliedly for perpendicular injection, and increases with beam energy increasing. (authors)

  11. Bootstrap current of fast ions in neutral beam injection heating

    International Nuclear Information System (INIS)

    The bootstrap current of fast ions produced by neutral beam injection (NBI) is investigated in a large-aspect-ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are reported. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current taken into consideration, the net current density obviously decreases; at the same time, the peak of the current moves towards the central plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the NBI but also on the ratio of the velocity of fast ions to the critical velocity: the value of the net current is small for neutral beam parallel injection, but increases severalfold for perpendicular injection, and increases with increasing beam energy. (paper)

  12. Variance estimation in neutron coincidence counting using the bootstrap method

    International Nuclear Information System (INIS)

    In the study, we demonstrate the implementation of the “bootstrap” method for a reliable estimation of the statistical error in Neutron Multiplicity Counting (NMC) on plutonium samples. The “bootstrap” method estimates the variance of a measurement through a re-sampling process, in which a large number of pseudo-samples are generated, from which the so-called bootstrap distribution is generated. The outline of the present study is to give a full description of the bootstrapping procedure, and to validate, through experimental results, the reliability of the estimated variance. Results indicate both a very good agreement between the measured variance and the variance obtained through the bootstrap method, and a robustness of the method with respect to the duration of the measurement and the bootstrap parameters

  13. Variance estimation in neutron coincidence counting using the bootstrap method

    Energy Technology Data Exchange (ETDEWEB)

    Dubi, C., E-mail: chendb331@gmail.com [Physics Department, Nuclear Research Center of the Negev, P.O.B. 9001 Beer Sheva (Israel); Ocherashvilli, A.; Ettegui, H. [Physics Department, Nuclear Research Center of the Negev, P.O.B. 9001 Beer Sheva (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Via E. Fermi, 2749 JRC, Ispra (Italy)

    2015-09-11

    In the study, we demonstrate the implementation of the “bootstrap” method for a reliable estimation of the statistical error in Neutron Multiplicity Counting (NMC) on plutonium samples. The “bootstrap” method estimates the variance of a measurement through a re-sampling process, in which a large number of pseudo-samples are generated, from which the so-called bootstrap distribution is generated. The outline of the present study is to give a full description of the bootstrapping procedure, and to validate, through experimental results, the reliability of the estimated variance. Results indicate both a very good agreement between the measured variance and the variance obtained through the bootstrap method, and a robustness of the method with respect to the duration of the measurement and the bootstrap parameters.

  14. Bootstrapping pre-averaged realized volatility under market microstructure noise

    DEFF Research Database (Denmark)

    Hounyo, Ulrich; Goncalves, Sílvia; Meddahi, Nour

    The main contribution of this paper is to propose a bootstrap method for inference on integrated volatility based on the pre-averaging approach of Jacod et al. (2009), where the pre-averaging is done over all possible overlapping blocks of consecutive observations. The overlapping nature of the pre......-averaged returns implies that these are kn-dependent with kn growing slowly with the sample size n. This motivates the application of a blockwise bootstrap method. We show that the "blocks of blocks" bootstrap method suggested by Politis and Romano (1992) (and further studied by Bühlmann and Künsch (1995)) is...... valid only when volatility is constant. The failure of the blocks of blocks bootstrap is due to the heterogeneity of the squared pre-averaged returns when volatility is stochastic. To preserve both the dependence and the heterogeneity of squared pre-averaged returns, we propose a novel procedure that...

  15. 'Bootstrap' Configuration for Multistage Pulse-Tube Coolers

    Science.gov (United States)

    Nguyen, Bich; Nguyen, Lauren

    2008-01-01

    A bootstrap configuration has been proposed for multistage pulse-tube coolers that, for instance, provide final-stage cooling to temperatures as low as 20 K. The bootstrap configuration supplants the conventional configuration, in which customarily the warm heat exchangers of all stages reject heat at ambient temperature. In the bootstrap configuration, the warm heat exchanger, the inertance tube, and the reservoir of each stage would be thermally anchored to the cold heat exchanger of the next warmer stage. The bootstrapped configuration is superior to the conventional setup, in some cases increasing the 20 K cooler's coefficient of performance two-fold over that of an otherwise equivalent conventional layout. The increased efficiency could translate into less power consumption, less cooler mass, and/or lower cost for a given amount of cooling.

  16. Filter and modified stepwedge bootstrap sensitometry in medical radiography

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Akira

    1988-05-01

    Two new bootstrap methods for determining characteristic curves of radiographic screen/film systems are presented : filter bootstrap sensitometry and modified stepwedge bootstrap sensitometry. Both are intensity-scale sensitometries since the radiation intensity can be varied through use of a combination of inverse square and metal filters. Characteristic curves obtained by these methods are compared with those from screen/film systems using inverse square sensitometry as a reference standard of accuracy. The precision of all three methods is better than +- 2 % with agreement among generally being within 3 % over the useful density range. By these bootstrap methods, it is possible to obtain characteristic curves agreeing well with those using the inverse square method for a relatively short distance, and make radiographic sensitometry practical and convenient at most medical institutions.

  17. On the range of validity of the autoregressive sieve bootstrap

    CERN Document Server

    Kreiss, Jens-Peter; Politis, Dimitris N; 10.1214/11-AOS900

    2012-01-01

    We explore the limits of the autoregressive (AR) sieve bootstrap, and show that its applicability extends well beyond the realm of linear time series as has been previously thought. In particular, for appropriate statistics, the AR-sieve bootstrap is valid for stationary processes possessing a general Wold-type autoregressive representation with respect to a white noise; in essence, this includes all stationary, purely nondeterministic processes, whose spectral density is everywhere positive. Our main theorem provides a simple and effective tool in assessing whether the AR-sieve bootstrap is asymptotically valid in any given situation. In effect, the large-sample distribution of the statistic in question must only depend on the first and second order moments of the process; prominent examples include the sample mean and the spectral density. As a counterexample, we show how the AR-sieve bootstrap is not always valid for the sample autocovariance even when the underlying process is linear.

  18. Monotonicity-preserving bootstrapped kriging metamodels for expensive simulations

    OpenAIRE

    Kleijnen, Jack P.C.; Beers, W.C.M. van

    2013-01-01

    Kriging (Gaussian process, spatial correlation) metamodels approximate the Input/Output (I/O) functions implied by the underlying simulation models; such metamodels serve sensitivity analysis and optimization, especially for computationally expensive simulations. In practice, simulation analysts often know that the I/O function is monotonic. To obtain a Kriging metamodel that preserves this known shape, this article uses bootstrapping (or resampling). Parametric bootstrapping assuming normali...

  19. Bootstrapped Multinomial Logistic Regression on Apnea Detection Using ECG Data

    OpenAIRE

    Sanabila, Hadaiq R.; Fanany, Mohamad Ivan; Jatmiko, Wisnu; Arymurthy, Aniati Murni

    2010-01-01

    In designing a classification system, one of the most important considerations is how optimal the classifier will adapt and give best generalization when it is given data from unknown model distribution. Unlike linear regression, logistic regression has no simple formula to assess its generalization ability. In such cases, bootstrapping offers an advantage over analytical methods thanks to its simplicity. This paper presents an analysis of bootstrapped multinomial logistic regression appli...

  20. Bootstrap transition to high beta equilibrium in helical system

    International Nuclear Information System (INIS)

    It is shown theoretically and computationally that helical magnetic field, produced by continuous winding helical coils and without the toroidal coil, can sustain MHD stable high beta plasma. Pressure driven toroidal current (bootstrap current) cancels the external magnetic field and reduces the MHD potential energy, depending on the plasma beta values. Ramp-up of heating power input induces bootstrap transition to higher beta plasmas with flat-top pressure profiles. Helical pitch parameter dependence of MHD stability is analyzed. (author)

  1. Bootstrap current for tokamak plasma with anisotropic electron temperature

    International Nuclear Information System (INIS)

    The neoclassical bootstrap current for an anisotropic plasma has been studied in a large aspect-ratio tokamak. The enhancement factor due to the temperature anisotropy in the equilibrium electron distribution function is explicitly calculated, and is shown to reach to about 1.5 when the perpendicular temperature is twice as large as the parallel temperature. This bootstrap current is also predicted to have the component proportional to the radial electric field even in an axisymmetric magnetic field. (author)

  2. Bootstrapping the statistical uncertainties of NN scattering data

    International Nuclear Information System (INIS)

    We use the Monte Carlo bootstrap as a method to simulate pp and np scattering data below pion production threshold from an initial set of over 6700 experimental mutually 3σ consistent data. We compare the results of the bootstrap, with 1020 statistically generated samples of the full database, with the standard covariance matrix method of error propagation. No significant differences in scattering observables and phase shifts are found. This suggests alternative strategies for propagating errors of nuclear forces in nuclear structure calculations

  3. Generalized bootstrap equations and possible implications for the NLO Odderon

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, J. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Vacca, G.P. [INFN, Sezione di Bologna (Italy)

    2013-07-15

    We formulate and discuss generalized bootstrap equations in nonabelian gauge theories. They are shown to hold in the leading logarithmic approximation. Since their validity is related to the self-consistency of the Steinmann relations for inelastic production amplitudes they can be expected to be valid also in NLO. Specializing to the N=4 SYM, we show that the validity in NLO of these generalized bootstrap equations allows to find the NLO Odderon solution with intercept exactly at one.

  4. Bootstrap tests in linear models with many regressors

    OpenAIRE

    Patrick Richard

    2014-01-01

    This paper is concerned with bootstrap hypothesis testing in high dimensional linear regression models. Using a theoretical framework recently introduced by Anatolyev (2012), we show that bootstrap F, LR and LM tests are asymptotically valid even when the numbers of estimated parameters and tested restrictions are not asymptotically negligible fractions of the sample size. These results are derived for models with iid error terms, but Monte Carlo evidence suggests that they extend to the wild...

  5. Bootstrapping and Bartlett corrections in the cointegrated VAR model

    OpenAIRE

    Omtzigt, P.H.; Fachin, S.

    2002-01-01

    The small sample properties of tests on long-run coefficients in cointegrated systems are still a matter of concern to applied econometricians. We compare the performance of the Bartlett correction, the bootstrap and the fast double bootstrap for tests on ccointegration parameters in the maximum likelihood framework. We show by means of a theoretical result and simulations that all three procedures should be based on the unrestricted estimate of the cointegration vectors. The fast double boot...

  6. Spectrum of local boundary operators from boundary form factor bootstrap

    CERN Document Server

    Szots, M

    2007-01-01

    Using the recently introduced boundary form factor bootstrap equations, we map the complete space of their solutions for the boundary version of the scaling Lee-Yang model and sinh-Gordon theory. We show that the complete space of solutions, graded by the ultraviolet behaviour of the form factors can be brought into correspondence with the spectrum of local boundary operators expected from boundary conformal field theory, which is a major evidence for the correctness of the boundary form factor bootstrap framework.

  7. BOOTSTRAP-BASED STATISTICAL THRESHOLDING FOR MEG SOURCE RECONSTRUCTION IMAGES

    OpenAIRE

    Sekihara, Kensuke; Sahani, Maneesh; Nagarajan, Srikantan S.

    2004-01-01

    This paper proposes a bootstrap-based statistical method for extracting target source activities from MEG/EEG source reconstruction results. The method requires measurements in a control condition, which contains only non-target source activities. The method derives, at each pixel location, an empirical probability distribution of the non-target source activity using bootstrapped reconstruction obtained from the control period. The statistical threshold that can extract the target source acti...

  8. On the range of validity of the autoregressive sieve bootstrap

    OpenAIRE

    Kreiss, Jens-Peter; Paparoditis, Efstathios; Politis, Dimitris N.

    2012-01-01

    We explore the limits of the autoregressive (AR) sieve bootstrap, and show that its applicability extends well beyond the realm of linear time series as has been previously thought. In particular, for appropriate statistics, the AR-sieve bootstrap is valid for stationary processes possessing a general Wold-type autoregressive representation with respect to a white noise; in essence, this includes all stationary, purely nondeterministic processes, whose spectral density is everywhere positive....

  9. Conformal collider physics from the lightcone bootstrap

    Science.gov (United States)

    Li, Daliang; Meltzer, David; Poland, David

    2016-02-01

    We analytically study the lightcone limit of the conformal bootstrap equations for 4-point functions containing global symmetry currents and the stress tensor in 3d CFTs. We show that the contribution of the stress tensor to the anomalous dimensions of large spin double-twist states is negative if and only if the conformal collider physics bounds are satisfied. In the context of AdS/CFT these results indicate a relation between the attractiveness of AdS gravity and positivity of the CFT energy flux. We also study the contribution of non-Abelian conserved currents to the anomalous dimensions of double- twist operators, corresponding to the gauge binding energy of 2-particle states in AdS. We show that the representation of the double-twist state determines the sign of the gauge binding energy if and only if the coefficients appearing in the current 3-point function satisfies a similar bound, which is equivalent to an upper bound on the charge flux asymmetry of the CFT.

  10. An Algebraic Approach to the Analytic Bootstrap

    CERN Document Server

    Alday, Luis F

    2015-01-01

    We develop an algebraic approach to the analytic bootstrap in CFTs. By acting with the Casimir operator on the crossing equation we map the problem of doing large spin sums to any desired order to the problem of solving a set of recursion relations. We compute corrections to the anomalous dimension of large spin operators due to the exchange of a primary and its descendants in the crossed channel and show that this leads to a Borel-summable expansion. We analyse higher order corrections to the microscopic CFT data in the direct channel and its matching to infinite towers of operators in the crossed channel. We apply this method to the critical $O(N)$ model. At large $N$ we reproduce the first few terms in the large spin expansion of the known two-loop anomalous dimensions of higher spin currents in the traceless symmetric representation of $O(N)$ and make further predictions. At small $N$ we present the results for the truncated large spin expansion series of anomalous dimensions of higher spin currents.

  11. Bootstrap inference longitudinal semiparametric regression model

    Science.gov (United States)

    Pane, Rahmawati; Otok, Bambang Widjanarko; Zain, Ismaini; Budiantara, I. Nyoman

    2016-02-01

    Semiparametric regression contains two components, i.e. parametric and nonparametric component. Semiparametric regression model is represented by yt i=μ (x˜'ti,zt i)+εt i where μ (x˜'ti,zt i)=x˜'tiβ ˜+g (zt i) and yti is response variable. It is assumed to have a linear relationship with the predictor variables x˜'ti=(x1 i 1,x2 i 2,…,xT i r) . Random error εti, i = 1, …, n, t = 1, …, T is normally distributed with zero mean and variance σ2 and g(zti) is a nonparametric component. The results of this study showed that the PLS approach on longitudinal semiparametric regression models obtain estimators β˜^t=[X'H(λ)X]-1X'H(λ )y ˜ and g˜^λ(z )=M (λ )y ˜ . The result also show that bootstrap was valid on longitudinal semiparametric regression model with g^λ(b )(z ) as nonparametric component estimator.

  12. Remarks on bootstrap percolation in metric networks

    International Nuclear Information System (INIS)

    We examine bootstrap percolation in d-dimensional, directed metric graphs in the context of recent measurements of firing dynamics in 2D neuronal cultures. There are two regimes depending on the graph size N. Large metric graphs are ignited by the occurrence of critical nuclei, which initially occupy an infinitesimal fraction, f* → 0, of the graph and then explode throughout a finite fraction. Smaller metric graphs are effectively random in the sense that their ignition requires the initial ignition of a finite, unlocalized fraction of the graph, f* > 0. The crossover between the two regimes is at a size N* which scales exponentially with the connectivity range λ like N* ∼ exp λd. The neuronal cultures are finite metric graphs of size N ≅ 105 - 106, which, for the parameters of the experiment, is effectively random since N *. This explains the seeming contradiction in the observed finite f* in these cultures. Finally, we discuss the dynamics of the firing front

  13. Quantum bootstrapping via compressed quantum Hamiltonian learning

    International Nuclear Information System (INIS)

    A major problem facing the development of quantum computers or large scale quantum simulators is that general methods for characterizing and controlling are intractable. We provide a new approach to this problem that uses small quantum simulators to efficiently characterize and learn control models for larger devices. Our protocol achieves this by using Bayesian inference in concert with Lieb–Robinson bounds and interactive quantum learning methods to achieve compressed simulations for characterization. We also show that the Lieb–Robinson velocity is epistemic for our protocol, meaning that information propagates at a rate that depends on the uncertainty in the system Hamiltonian. We illustrate the efficiency of our bootstrapping protocol by showing numerically that an 8 qubit Ising model simulator can be used to calibrate and control a 50 qubit Ising simulator while using only about 750 kilobits of experimental data. Finally, we provide upper bounds for the Fisher information that show that the number of experiments needed to characterize a system rapidly diverges as the duration of the experiments used in the characterization shrinks, which motivates the use of methods such as ours that do not require short evolution times. (fast track communication)

  14. Conformal Collider Physics from the Lightcone Bootstrap

    CERN Document Server

    Li, Daliang; Poland, David

    2015-01-01

    We analytically study the lightcone limit of the conformal bootstrap equations for 4-point functions containing global symmetry currents and the stress tensor in 3d CFTs. We show that the contribution of the stress tensor to the anomalous dimensions of large spin double-twist states is negative if and only if the conformal collider physics bounds are satisfied. In the context of AdS/CFT these results indicate a relation between the attractiveness of AdS gravity and positivity of the CFT energy flux. We also study the contribution of non-Abelian conserved currents to the anomalous dimensions of double-twist operators, corresponding to the gauge binding energy of 2-particle states in AdS. We show that the representation of the double-twist state determines the sign of the gauge binding energy if and only if the coefficient appearing in the current 3-point function satisfies a similar bound, which is equivalent to an upper bound on the charge flux asymmetry of the CFT.

  15. Bootstrapping Object Coreferencing on the Semantic Web

    Institute of Scientific and Technical Information of China (English)

    Wei Hu; Yu-Zhong Qu; Xing-Zhi Sun

    2011-01-01

    An object on the Semantic Web is likely to be denoted with several URIs by different parties.Object coreferencing is a process to identify "equivalent" URIs of objects for achieving a better Data Web.In this paper,we propose a bootstrapping approach for object coreferencing on the Semantic Web.For an object URI,we firstly establish a kernel that consists of semantically equivalent URIs from the same-as,(inverse) functional properties and (max-)cardinalities,and then extend the kernel with respect to the textual descriptions (e.g.,labels and local names) of URIs.We also propose a trustworthiness-based method to rank the coreferent URIs in the kernel as well as a similarity-based method for ranking the URIs in the extension of the kernel.We implement the proposed approach,called ObjectCoref,on a large-scale dataset that contains 76 million URIs collected by the Falcons search engine until 2008.The evaluation on precision,relative recall and response time demonstrates the feasibility of our approach.Additionally,we apply the proposed approach to investigate the popularity of the URI alias phenomenon on the current Semantic Web.

  16. Tie the straps: Uniform bootstrap con fidence bands for bounded influence curve estimators

    OpenAIRE

    Härdle, Wolfgang Karl; Ritov, Ya'Acov; Wang, Weining

    2013-01-01

    We consider theoretical bootstrap coupling techniques for nonparametric robust smoothers and quantile regression, and verify the bootstrap improvement. To cope with curse of dimensionality, a variant of coupling bootstrap techniques are developed for additive models with both symmetric error distributions and further extension to the quantile regression framework. Our bootstrap method can be used in many situations like constructing con dence intervals and bands. We demonstrate the bootstrap ...

  17. Control of bootstrap current in the pedestal region of tokamaks

    International Nuclear Information System (INIS)

    The high confinement mode (H-mode) plasmas in the pedestal region of tokamaks are characterized by steep gradient of the radial electric field, and sonic poloidal Up,m flow that consists of poloidal components of the E×B flow and the plasma flow velocity that is parallel to the magnetic field B. Here, E is the electric field. The bootstrap current that is important for the equilibrium, and stability of the pedestal of H-mode plasmas is shown to have an expression different from that in the conventional theory. In the limit where ‖Up,m‖≫ 1, the bootstrap current is driven by the electron temperature gradient and inductive electric field fundamentally different from that in the conventional theory. The bootstrap current in the pedestal region can be controlled through manipulating Up,m and the gradient of the radial electric. This, in turn, can control plasma stability such as edge-localized modes. Quantitative evaluations of various coefficients are shown to illustrate that the bootstrap current remains finite when ‖Up,m‖ approaches infinite and to provide indications how to control the bootstrap current. Approximate analytic expressions for viscous coefficients that join results in the banana and plateau-Pfirsch-Schluter regimes are presented to facilitate bootstrap and neoclassical transport simulations in the pedestal region

  18. Control of bootstrap current in the pedestal region of tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Shaing, K. C. [Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan City 70101, Taiwan (China); Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53796 (United States); Lai, A. L. [Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan City 70101, Taiwan (China)

    2013-12-15

    The high confinement mode (H-mode) plasmas in the pedestal region of tokamaks are characterized by steep gradient of the radial electric field, and sonic poloidal U{sub p,m} flow that consists of poloidal components of the E×B flow and the plasma flow velocity that is parallel to the magnetic field B. Here, E is the electric field. The bootstrap current that is important for the equilibrium, and stability of the pedestal of H-mode plasmas is shown to have an expression different from that in the conventional theory. In the limit where ‖U{sub p,m}‖≫ 1, the bootstrap current is driven by the electron temperature gradient and inductive electric field fundamentally different from that in the conventional theory. The bootstrap current in the pedestal region can be controlled through manipulating U{sub p,m} and the gradient of the radial electric. This, in turn, can control plasma stability such as edge-localized modes. Quantitative evaluations of various coefficients are shown to illustrate that the bootstrap current remains finite when ‖U{sub p,m}‖ approaches infinite and to provide indications how to control the bootstrap current. Approximate analytic expressions for viscous coefficients that join results in the banana and plateau-Pfirsch-Schluter regimes are presented to facilitate bootstrap and neoclassical transport simulations in the pedestal region.

  19. Application of bootstrap method for assessment of linear regression models; Zastosowanie metody bootstrap do badania liniowych modeli regresyjnych

    Energy Technology Data Exchange (ETDEWEB)

    Urbanski, P.; Kowalska, E.

    1997-12-31

    The principle of the bootstrap methodology applied for the assessment of parameters and prediction ability of the linear regression models was presented. Application of this method was shown on the example of calibration of the radioisotope sulphuric acid concentration gauge. The bootstrap method allows to determine not only the numerical values of the regression coefficients, but also enables to investigate their distributions. (author). 11 refs, 12 figs, 3 tabs.

  20. Avaliação de herbicidas aplicados em pré e pós-emergência na cultura da cebola (Allium cepa L.) Herbicides applied in pre and pos-emergence on transplanted onion crop (Allium cepa L.)

    OpenAIRE

    Ferreira, J. C.

    1985-01-01

    Foram conduzidos em áreas de agricultores do Projeto de Irrigação de Bebedouro, no município de Petrolina, PE, dois experimentos de campo, onde estudouse o comportamento de diferentes herbicidas, no controle de plantas daninhas e na tolerância da cultura da cebola transpl antada. Os tratamentos foram distribuídos em blocos ao acaso com três repetições, em um Latossolo Amarelo, fase arenosa, com baixos teores de argila e matéria orgânica. No experimento I aplicaram- se oxadiazon 1,00, pentimet...

  1. A Bootstrap Approach to Martian Manufacturing

    Science.gov (United States)

    Dorais, Gregory A.

    2004-01-01

    In-Situ Resource Utilization (ISRU) is an essential element of any affordable strategy for a sustained human presence on Mars. Ideally, Martian habitats would be extremely massive to allow plenty of room to comfortably live and work, as well as to protect the occupants from the environment. Moreover, transportation and power generation systems would also require significant mass if affordable. For our approach to ISRU, we use the industrialization of the U.S. as a metaphor. The 19th century started with small blacksmith shops and ended with massive steel mills primarily accomplished by blacksmiths increasing their production capacity and product size to create larger shops, which produced small mills, which produced the large steel mills that industrialized the country. Most of the mass of a steel mill is comprised of steel in simple shapes, which are produced and repaired with few pieces of equipment also mostly made of steel in basic shapes. Due to this simplicity, we expect that the 19th century manufacturing growth can be repeated on Mars in the 21st century using robots as the primary labor force. We suggest a "bootstrap" approach to manufacturing on Mars that uses a "seed" manufacturing system that uses regolith to create major structural components and spare parts. The regolith would be melted, foamed, and sintered as needed to fabricate parts using casting and solid freeform fabrication techniques. Complex components, such as electronics, would be brought from Earth and integrated as needed. These parts would be assembled to create additional manufacturing systems, which can be both more capable and higher capacity. These subsequent manufacturing systems could refine vast amounts of raw materials to create large components, as well as assemble equipment, habitats, pressure vessels, cranes, pipelines, railways, trains, power generation stations, and other facilities needed to economically maintain a sustained human presence on Mars.

  2. Assessment of bootstrap resampling performance for PET data

    International Nuclear Information System (INIS)

    Bootstrap resampling has been successfully used for estimation of statistical uncertainty of parameters such as tissue metabolism, blood flow or displacement fields for image registration. The performance of bootstrap resampling as applied to PET list-mode data of the human brain and dedicated phantoms is assessed in a novel and systematic way such that: (1) the assessment is carried out in two resampling stages: the ‘real world’ stage where multiple reference datasets of varying statistical level are generated and the ‘bootstrap world’ stage where corresponding bootstrap replicates are generated from the reference datasets. (2) All resampled datasets were reconstructed yielding images from which multiple voxel and regions of interest (ROI) values were extracted to form corresponding distributions between the two stages. (3) The difference between the distributions from both stages was quantified using the Jensen–Shannon divergence and the first four moments. It was found that the bootstrap distributions are consistently different to the real world distributions across the statistical levels. The difference was explained by a shift in the mean (up to 33% for voxels and 14% for ROIs) being proportional to the inverse square root of the statistical level (number of counts). Other moments were well replicated by the bootstrap although for very low statistical levels the estimation of the variance was poor. Therefore, the bootstrap method should be used with care when estimating systematic errors (bias) and variance when very low statistical levels are present such as in early time frames of dynamic acquisitions, when the underlying population may not be sufficiently represented. (paper)

  3. Seletividade de herbicidas aplicados na grama Batatais e na grama São Carlos Selectivity of herbicides applied on Bahiagrass and Broadleaf Carpetgrass turfs

    OpenAIRE

    N.V. Costa; Martins, D; A.C.P. Rodrigues; L.A. Cardoso

    2010-01-01

    Objetivou-se avaliar a seletividade de herbicidas aplicados na grama Batatais (Paspalum notatum) e na grama São Carlos (Axonopus compressus) em campo. O delineamento experimental utilizado foi o de blocos casualizados com quatro repetições. As gramas foram cortadas a 3 cm de altura e, em seguida, realizaram-se as aplicações dos herbicidas. Os tratamentos utilizados foram: testemunha (sem aplicação), fluazifop-p-butil (125 g ha-1), sethoxydim+óleo mineral (276 g ha-1 + 0,5% v v-1 de Assist), b...

  4. Negligência infantil a partir do Child Neglect Index aplicado no Brasil

    Directory of Open Access Journals (Sweden)

    Mara Silvia Pasian

    2015-03-01

    Full Text Available Este estudo objetivou descrever a utilização do Child Neglect Indexpara identificar casos de crianças negligenciadas por seus pais/cuidadores no contexto brasileiro. Após adaptação inicial à realidade sociocultural brasileira, o instrumento foi aplicado em três grupos de indivíduos, cada qual com 30 díades de crianças/pais, totalizando 90 díades (n=180, assim compostos: G1 (primeiro grupo = casos oficialmente notificados por negligência infantil; G2 (segundo grupo = casos suspeitos de negligência não notificados; G3 (terceiro grupo = casos sem suspeita de negligência ou outra forma de maus-tratos (grupo de comparação; além de um quarto grupo de professoras dessas crianças (n=11. Os resultados apontaram altos escores no índice de negligência em G1 e G2, e baixos escores em G3, sugerindo presença de indicadores de falta de supervisão parental referentes a cuidados com alimentação, vestimenta, higiene, saúde física, saúde mental e educação nos dois primeiros grupos avaliados, comparativamente às crianças sem suspeita de maus-tratos. Os atuais achados empíricos, embora preliminares em termos de adaptação do Child Neglect Index ao contexto do Brasil, foram promissores ao sinalizar potencial do instrumento como recurso para detecção/confirmação da negligência infantil, estimulando novas investigações e aprimoramento desse recurso técnico para favorecer adequada identificação e intervenção nesses casos.

  5. High bootstrap current in RF-heated discharges

    International Nuclear Information System (INIS)

    Purely non-inductive steady-state discharges in tokamak reactors will require a large bootstrap current, Ibtot, in order to minimize the amounts of power in external current drive systems. In present day tokamaks, high bootstrap current discharges are produced under various conditions. It has been demonstrated that the on-axis RF heatings are good candidates for producing a large bootstrap current, especially the fast magnetosonic wave direct electron heating (FWEH), for which power deposition is centrally peaked. Moreover, the heating and current drive methods using RF waves could be used as external sources to optimize Iboot through the current profile control. In this paper, the dependence of Iboot on the profiles of the plasma density, temperature, pressure and current density is analysed using a theoretical approach with a matrix formulation. Examples of quasi-steady-state discharges with large bootstrap current fraction using FWEH on Tore Supra are given. Examples of high bootstrap current fractions on reverse shear discharges (TFTR, DIII-D, ...) are also mentioned. Purely non-inductive discharges with improved confinement by combination of FWEH and lower hybrid current drive are analysed and the extrapolation to the so-called 'Tore Supra CIEL phase' is reported. (author)

  6. A bootstrap estimation scheme for chemical compositional data with nondetects

    Science.gov (United States)

    Palarea-Albaladejo, J; Martín-Fernández, J.A; Olea, Ricardo A.

    2014-01-01

    The bootstrap method is commonly used to estimate the distribution of estimators and their associated uncertainty when explicit analytic expressions are not available or are difficult to obtain. It has been widely applied in environmental and geochemical studies, where the data generated often represent parts of whole, typically chemical concentrations. This kind of constrained data is generically called compositional data, and they require specialised statistical methods to properly account for their particular covariance structure. On the other hand, it is not unusual in practice that those data contain labels denoting nondetects, that is, concentrations falling below detection limits. Nondetects impede the implementation of the bootstrap and represent an additional source of uncertainty that must be taken into account. In this work, a bootstrap scheme is devised that handles nondetects by adding an imputation step within the resampling process and conveniently propagates their associated uncertainly. In doing so, it considers the constrained relationships between chemical concentrations originated from their compositional nature. Bootstrap estimates using a range of imputation methods, including new stochastic proposals, are compared across scenarios of increasing difficulty. They are formulated to meet compositional principles following the log-ratio approach, and an adjustment is introduced in the multivariate case to deal with nonclosed samples. Results suggest that nondetect bootstrap based on model-based imputation is generally preferable. A robust approach based on isometric log-ratio transformations appears to be particularly suited in this context. Computer routines in the R statistical programming language are provided. 

  7. Locality, bulk equations of motion and the conformal bootstrap

    CERN Document Server

    Kabat, Daniel

    2016-01-01

    We develop an approach to construct local bulk operators in a CFT to order 1/N^2. Since 4-point functions are not fixed by conformal invariance we use the OPE to categorize possible forms for a bulk operator. Using previous results on 3-point functions we construct a local bulk operator in each OPE channel. We then impose the condition that the bulk operators constructed in different channels agree, and hence give rise to a well-defined bulk operator. We refer to this condition as the "bulk bootstrap." We argue and explicitly show in some examples that the bulk bootstrap leads to some of the same results as the regular conformal bootstrap. In fact the bulk bootstrap provides an easier way to determine some CFT data, since it does not require knowing the form of the conformal blocks. This analysis clarifies previous results on the relation between bulk locality and the bootstrap for theories with a 1/N expansion, and it identifies a simple and direct way in which OPE coefficients and anomalous dimensions deter...

  8. Progress Toward Steady State Tokamak Operation Exploiting the high bootstrap current fraction regime

    Science.gov (United States)

    Ren, Q.

    2015-11-01

    Recent DIII-D experiments have advanced the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Fully noninductive plasmas with extremely high values of the poloidal beta, βp >= 4 , have been sustained at βT >= 2 % for long durations with excellent energy confinement quality (H98y,2 >= 1 . 5) and internal transport barriers (ITBs) generated at large minor radius (>= 0 . 6) in all channels (Te, Ti, ne, VTf). Large bootstrap fraction (fBS ~ 80 %) has been obtained with high βp. ITBs have been shown to be compatible with steady state operation. Because of the unusually large ITB radius, normalized pressure is not limited to low βN values by internal ITB-driven modes. βN up to ~4.3 has been obtained by optimizing the plasma-wall distance. The scenario is robust against several variations, including replacing some on-axis with off-axis neutral beam injection (NBI), adding electron cyclotron (EC) heating, and reducing the NBI torque by a factor of 2. This latter observation is particularly promising for extension of the scenario to EAST, where maximum power is obtained with balanced NBI injection, and to a reactor, expected to have low rotation. However, modeling of this regime has provided new challenges to state-of-the-art modeling capabilities: quasilinear models can dramatically underpredict the electron transport, and the Sauter bootstrap current can be insufficient. The analysis shows first-principle NEO is in good agreement with experiments for the bootstrap current calculation and ETG modes with a larger saturated amplitude or EM modes may provide the missing electron transport. Work supported in part by the US DOE under DE-FC02-04ER54698, DE-AC52-07NA

  9. Métodos de auxílio multicritério à decisão aplicados a problemas de PCP: mapeamento da produção em periódicos publicados no Brasil Multicriteria decision aid methods applied to PPC problems: a mapping of papers published in Brazilian journals

    OpenAIRE

    Dey Salvador Sanchez Rodriguez; Helder Gomes Costa; Luiz Felipe Roris Rodriguez Scavarda do Carmo

    2013-01-01

    O presente trabalho tem por objetivo estabelecer um mapeamento da produção científica divulgada em importantes periódicos publicados no Brasil sobre a aplicação de Métodos de Auxílio Multicritério à Decisão (AMD) à modelagem de problemas de Planejamento e Controle da Produção. O mapeamento contemplou 32 artigos, que foram selecionados criteriosamente, tendo como base a lista de periódicos científicos oferecida no Scielo e em importantes sociedades científicas brasileiras no âmbito da Engenhar...

  10. Implementation of bootstrap current effects in the PIES code

    International Nuclear Information System (INIS)

    The PIES code (Princeton Iterative Equilibrium Solver) has been modified to take into account the effects of bootstrap current. A simple bootstrap current model, applicable to tokamaks, is presently being employed. Pressure flattening, caused by the evolution of islands, has an important effect on the bootstrap current, which in turn has an important large effect on the island width. Analytic models have shown that the overall result of this interaction is, for negative shear, a destabilization of the islands. Recently, Chang et al., has shown that good agreement exists between the analytic expression proposed by reference and experiments on TFTR. Approximations used in this analytic expression, such as the expressions for Δ'(w), axe avoided in the calculations done with the PIES code. A comparison of the two results will be presented

  11. Point Set Denoising Using Bootstrap-Based Radial Basis Function

    Science.gov (United States)

    Ramli, Ahmad; Abd. Majid, Ahmad

    2016-01-01

    This paper examines the application of a bootstrap test error estimation of radial basis functions, specifically thin-plate spline fitting, in surface smoothing. The presence of noisy data is a common issue of the point set model that is generated from 3D scanning devices, and hence, point set denoising is one of the main concerns in point set modelling. Bootstrap test error estimation, which is applied when searching for the smoothing parameters of radial basis functions, is revisited. The main contribution of this paper is a smoothing algorithm that relies on a bootstrap-based radial basis function. The proposed method incorporates a k-nearest neighbour search and then projects the point set to the approximated thin-plate spline surface. Therefore, the denoising process is achieved, and the features are well preserved. A comparison of the proposed method with other smoothing methods is also carried out in this study. PMID:27315105

  12. A Bootstrap Algebraic Multilevel method for Markov Chains

    CERN Document Server

    Bolten, M; Brannick, J; Frommer, A; Kahl, K; Livshits, I

    2010-01-01

    This work concerns the development of an Algebraic Multilevel method for computing stationary vectors of Markov chains. We present an efficient Bootstrap Algebraic Multilevel method for this task. In our proposed approach, we employ a multilevel eigensolver, with interpolation built using ideas based on compatible relaxation, algebraic distances, and least squares fitting of test vectors. Our adaptive variational strategy for computation of the state vector of a given Markov chain is then a combination of this multilevel eigensolver and associated multilevel preconditioned GMRES iterations. We show that the Bootstrap AMG eigensolver by itself can efficiently compute accurate approximations to the state vector. An additional benefit of the Bootstrap approach is that it yields an accurate interpolation operator for many other eigenmodes. This in turn allows for the use of the resulting AMG hierarchy to accelerate the MLE steps using standard multigrid correction steps. The proposed approach is applied to a rang...

  13. No unitary bootstrap for the fractal Ising model

    CERN Document Server

    Golden, John

    2015-01-01

    We consider the conformal bootstrap for spacetime dimension $1bootstrap, showing that bounds can be - and indeed are - discontinuous in this limit. This discontinuity implies that for small $\\epsilon=d-1$ the expected critical exponents for the Ising model are disallowed, and in particular those of the $d-1$ expansion. Altogether these results strongly suggest that the Ising model universality class cannot be described by a unitary CFT below $d=2$. We argue this also from a bootstrap perspective, by showing that the $2\\leq d<4$ Ising "kink" splits into two features which grow apart below $d=2$.

  14. Addressing the P2P Bootstrap Problem for Small Networks

    CERN Document Server

    Wolinsky, David Isaac; Boykin, P Oscar; Figueiredo, Renato

    2010-01-01

    P2P overlays provide a framework for building distributed applications consisting of few to many resources with features including self-configuration, scalability, and resilience to node failures. Such systems have been successfully adopted in large-scale services for content delivery networks, file sharing, and data storage. In small-scale systems, they can be useful to address privacy concerns and for network applications that lack dedicated servers. The bootstrap problem, finding an existing peer in the overlay, remains a challenge to enabling these services for small-scale P2P systems. In large networks, the solution to the bootstrap problem has been the use of dedicated services, though creating and maintaining these systems requires expertise and resources, which constrain their usefulness and make them unappealing for small-scale systems. This paper surveys and summarizes requirements that allow peers potentially constrained by network connectivity to bootstrap small-scale overlays through the use of e...

  15. Design and Implementation of a Bootstrap Trust Chain

    Institute of Scientific and Technical Information of China (English)

    YU Fajiang; ZHANG Huanguo

    2006-01-01

    The chain of trust in bootstrap process is the basis of whole system trust in the trusted computing group (TCG) definition. This paper presents a design and implementation of a bootstrap trust chain in PC based on the Windows and today' commodity hardware, merely depends on availability of an embedded security module (ESM). ESM and security enhanced BIOS is the root of trust, PMBR (Pre-MBR) checks the integrity of boot data and Windows kernel, which is a checking agent stored in ESM. In the end, the paper analyzed the mathematic expression of the chain of trust and the runtime performance compared with the common booting process. The trust chain bootstrap greatly strengthens the security of personal computer system, and affects the runtime performance with only adding about 12% booting time.

  16. Investigations of dipole localization accuracy in MEG using the bootstrap.

    Science.gov (United States)

    Darvas, F; Rautiainen, M; Pantazis, D; Baillet, S; Benali, H; Mosher, J C; Garnero, L; Leahy, R M

    2005-04-01

    We describe the use of the nonparametric bootstrap to investigate the accuracy of current dipole localization from magnetoencephalography (MEG) studies of event-related neural activity. The bootstrap is well suited to the analysis of event-related MEG data since the experiments are repeated tens or even hundreds of times and averaged to achieve acceptable signal-to-noise ratios (SNRs). The set of repetitions or epochs can be viewed as a set of independent realizations of the brain's response to the experiment. Bootstrap resamples can be generated by sampling with replacement from these epochs and averaging. In this study, we applied the bootstrap resampling technique to MEG data from somatotopic experimental and simulated data. Four fingers of the right and left hand of a healthy subject were electrically stimulated, and about 400 trials per stimulation were recorded and averaged in order to measure the somatotopic mapping of the fingers in the S1 area of the brain. Based on single-trial recordings for each finger we performed 5000 bootstrap resamples. We reconstructed dipoles from these resampled averages using the Recursively Applied and Projected (RAP)-MUSIC source localization algorithm. We also performed a simulation for two dipolar sources with overlapping time courses embedded in realistic background brain activity generated using the prestimulus segments of the somatotopic data. To find correspondences between multiple sources in each bootstrap, sample dipoles with similar time series and forward fields were assumed to represent the same source. These dipoles were then clustered by a Gaussian Mixture Model (GMM) clustering algorithm using their combined normalized time series and topographies as feature vectors. The mean and standard deviation of the dipole position and the dipole time series in each cluster were computed to provide estimates of the accuracy of the reconstructed source locations and time series. PMID:15784414

  17. Beam-driven and bootstrap currents in JT-60 upgrade

    International Nuclear Information System (INIS)

    We recently performed beam-driven current-drive experiments with a low fraction of bootstrap currents in a wide range of plasma parameters in JT-60 upgrade. The evidence of current profile modification by the beam-driven current with tangential neutral beam injectors. A high βN, high βp and ELMy H-mode plasma with possibly fully non-inductive current-drive by beam-driven and bootstrap currents was maintained for a considerably long duration with the combined injection of quasi-perpendicular and co-tangential beams. (author) 4 refs., 7 figs

  18. Generalized bootstrap equations and possible implications for the NLO odderon

    International Nuclear Information System (INIS)

    We formulate and discuss generalized bootstrap equations in nonabelian gauge theories. They are shown to hold in the leading logarithmic approximation. Since their validity is related to the self-consistency of the Steinmann relations for inelastic production amplitudes they can be expected to be valid also in NLO. Specializing to the N=4 SYM, we show that the validity in NLO of these generalized bootstrap equations allows to find the NLO odderon solution with intercept exactly at one, a result which is valid also for the planar limit of QCD. (orig.)

  19. Experimental evidence for the bootstrap current in a tokamak

    International Nuclear Information System (INIS)

    The bootstrap current is a plasma current associated with trapped particles in a toroidal plasma. Magnetic measurements, such as the surface voltage, the internal inductance, and the Faraday rotation, are consistent with the existence of the neoclassical bootstrap current in tokamaks. The neoclassical trapped-particle correction to the electrical conductivity is also systematically validated against experiments. These results support the assertion that the generalized Ohm's law along the magnetic field is valid, as predicted by the neoclassical transport theory, while the perpendicular transport deviates from the neoclassical transport theory. (Author)

  20. Bootstrap current increment after siliconization on the HT-7 tokamak

    International Nuclear Information System (INIS)

    The authors present some results for the estimation of the bootstrap current after siliconization on the HT-7 tokamak. After siliconization, the plasma pressure gradient and the electron temperature near the boundary are larger than before siliconization. These factors influence the ratio of the bootstrap current to the total plasma current which increases from several per cent to above 10%. The results are expected to explain the previous experimental phenomena that, after siliconization, the plasma current profile is broadened and the higher current can be obtained easily on the HT-7 tokamak experiment

  1. Modelos alternativos de simulación Bootstrap

    OpenAIRE

    Pino Mejías, Rafael

    1992-01-01

    Se describen las características fundamentales de los métodos Bootstrap. Se analizan diversas problemáticas que presentan tales métodos, por lo que se presentan dos métodos alternativos dentro del método Bootstrap basado en la simulación de muestras (método II de Efron). En el primero se presenta un método, que a partir de un estudio de las propiedades algebraicas y estadísticas del conjunto de posibles muestras, utiliza un criterio probabilístico para detectar muestras "outliers". En el segu...

  2. Bootstrapped efficiency measures of oil blocks in Angola

    International Nuclear Information System (INIS)

    This paper investigates the technical efficiency of Angola oil blocks over the period 2002-2007. A double bootstrap data envelopment analysis (DEA) model is adopted composed in the first stage of a DEA-variable returns to scale (VRS) model and then followed in the second stage by a bootstrapped truncated regression. Results showed that on average, the technical efficiency has fluctuated over the period of study, but deep and ultradeep oil blocks have generally maintained a consistent efficiency level. Policy implications are derived.

  3. Bootstrapping Critical Ising Model on Three Dimensional Real Projective Space

    Science.gov (United States)

    Nakayama, Yu

    2016-04-01

    Given conformal data on a flat Euclidean space, we use crosscap conformal bootstrap equations to numerically solve the Lee-Yang model as well as the critical Ising model on a three dimensional real projective space. We check the rapid convergence of our bootstrap program in two dimensions from the exact solutions available. Based on the comparison, we estimate that our systematic error on the numerically solved one-point functions of the critical Ising model on a three dimensional real projective space is less than 1%. Our method opens up a novel way to solve conformal field theories on nontrivial geometries.

  4. PyCFTBoot: A flexible interface for the conformal bootstrap

    CERN Document Server

    Behan, Connor

    2016-01-01

    We introduce PyCFTBoot, a wrapper designed to reduce the barrier to entry in conformal bootstrap calculations that require semidefinite programming. Symengine and SDPB are used for the most intensive symbolic and numerical steps respectively. After reviewing the built-in algorithms for conformal blocks, we explain how to use the code through a number of examples that verify past results. As an application, we show that the multi-correlator bootstrap still appears to single out the Wilson-Fisher fixed points as special theories in dimensions between 3 and 4 despite the recent proof that they violate unitarity.

  5. Efeito de reguladores de crescimento, aplicados em diferentes épocas, e da incisão anelar dos ramos principais sobre a produção da laranjeira de umbigo 'Monte Parnaso' Production of 'Monte Parnaso' navel oranges in function of the application of growth regulators and girdlin

    Directory of Open Access Journals (Sweden)

    Gilmar Schäfer

    2001-08-01

    Full Text Available Com o propósito de reduzir a queda prematura de frutos e aumentar a produção de laranjeiras de umbigo 'Monte Parnaso' (Citrus sinensis [L.] Osbeck, no ano agrícola de 1997/98, plantas com seis anos de idade, enxertadas sobre Poncirus trifoliata (L. Raf., de um pomar comercial, da empresa Panorama Citros, situado no Município de Butiá, Estado do Rio Grande do Sul foram pulverizadas com os seguintes tratamentos: T1 Testemunha; T2 5ppm de AG3 no final da queda das pétalas, em setembro de 1988; T3 Incisão anelar da casca dos ramos principais 10 dias após a floração, em setembro de 1988; T4 Idem T2 + T3; T5 15ppm de 2,4-D em novembro de 1988; T6 Idem T4 + T5; T7 Incisão anelar da casca dos ramos principais em novembro de 1988; T8 Idem 5 + 7; T9 Idem T6 + T7; T10 Idem T6 + 10ppm de AG3 com 15ppm de 2,4-D em maio de 98; T11 Idem T9 + 10ppm de AG3 e 15ppm de 2,4-D em maio de 1988. O delineamento experimental adotado foi em blocos ao acaso, com quatro repetições usando-se três plantas úteis por parcela. Todos os tratamentos em relação a testemunha promoveram um aumento na ordem de 45% na produção de frutas em número e peso. O peso médio, sólidos solúveis totais, acidez total titulável e a percentagem de suco nos frutos não foram afetados significativamente.The present trial was carried out aiming to increase fruit set of 'Monte Parnaso' (Citrus sinensis [L.] Osbeck navel oranges budded on trifoliate orange (Poncirus trifoliata [L.] Raf. rootstocks grown in the State of Rio Grande do Sul, Brazil. In 1996, six-year-old navel orange trees were sprayed with growth regulators combined or not with girdling. The following treatments (T was conducted: T1 Control; T2 spraying of five ppm of GA3 at the end of petal fall; T3 girdling 10 days after petal fall; T4 T2 plus T3; T5 spraying of 15ppm 2.4-D; T6 T4 plus T5; T7 girdling in November 15th; T8 T5 plus T7; T9 T6 plus T7; T10 T6 plus spraying of 10ppm of GA3 and 15ppm of 2.4-D in May of

  6. Bootstrap Tests and Confidence Regions for Functions of a Covariance Matrix

    OpenAIRE

    Beran, Rudolf; Srivastava, Muni S.

    1985-01-01

    Bootstrap tests and confidence regions for functions of the population covariance matrix have the desired asymptotic levels, provided model restrictions, such as multiple eigenvalues in the covariance matrix, are taken into account in designing the bootstrap algorithm.

  7. Il bootstrap. Un'applicazione informatica per un problema di ricampionamento

    OpenAIRE

    Morana, Maria Teresa; Porcu, Mariano

    2002-01-01

    The aim of this paper is to give a simple introduction to the bootstrap techniques showing a basic computer algorithm. The algorithm displays, step by step, how to determinate a bootstrap confidence interval.

  8. A new resampling method for sampling designs without replacement: the doubled half bootstrap

    OpenAIRE

    Antal, Erika; Tillé, Yves

    2016-01-01

    A new and very fast method of bootstrap for sampling without replacement from a finite population is proposed. This method can be used to estimate the variance in sampling with unequal inclusion probabilities and does not require artificial populations or utilization of bootstrap weights. The bootstrap samples are directly selected from the original sample. The bootstrap procedure contains two steps: in the first step, units are selected once with Poisson sampling using the same inclusion pro...

  9. A frequency domain bootstrap for ratio statistics in time series analysis

    OpenAIRE

    Dahlhaus, R.; Janas, D.

    1996-01-01

    The asymptotic properties of the bootstrap in the frequency domain based on Studentized periodogram ordinates are studied. It is proved that this bootstrap approximation is valid for ratio statistics such as autocorrelations. By using Edgeworth expansions it is shown that the bootstrap approximation even outperforms the normal approximation. The results carry over to Whittle estimates. In a simulation study the behavior of the bootstrap is studied for empirical correlations and Whittle estima...

  10. PENGGUNAAN BOOTSTRAP DATA DEPENDEN UNTUK MEMBANGUN SELANG KEPERCAYAAN PADA PARAMETER MODEL PERAMALAN DATA STASIONER

    OpenAIRE

    Siana Halim; Herman Mallian

    2006-01-01

    The Bootstrap is a lively research area. A lot Of ideas are around and have let to quiet different proposals. In this paper we sketch briefly some Bootstrap methods for independent and dependent data. Finally we give an Bootstrap example for constructing confidence interval in the forecasting for stationer data. Abstract in Bahasa Indonesia : Bootstrap merupakan area penelitian yang terus berkembang. Ada banyak ide dan proposal-proposal yang berbeda telah diberikan oleh para peneliti. Namun d...

  11. First and second order analysis for periodic random arrays using block bootstrap methods

    OpenAIRE

    Dudek, Anna E.

    2016-01-01

    In the paper row-wise periodically correlated triangular arrays are considered. The period length is assumed to grow in time. The Fourier decomposition of the mean and autocovariance functions for each row of the matrix is presented. To construct bootstrap estimators of the Fourier coefficients two block bootstrap techniques are used. These are the circular version of the Generalized Seasonal Block Bootstrap and the Circular Block Bootstrap. Consistency results for both methods are presented....

  12. Inspeção a sistemas de climatização e conceção de um sistema de gestão da manutenção aplicado em edifícios universitários

    OpenAIRE

    Costa, José João de Sampaio Maia Lima

    2015-01-01

    Os requisitos legais impostos ao processo de manutenção das instalações de AVAC em edifícios evoluíram nos últimos 10 anos no sentido de uma crescente exigência, obrigando à existência de planos de manutenção preventiva, livros de ocorrências, inspeções obrigatórias a equipamentos, auditorias ou certi cações energéticas. Para os responsáveis da gestão da manutenção de edifícios, em particular para os que gerem uma quantidade signi cativa de equipamentos e instalações, fazê-lo sem o auxílio de...

  13. Normal Limits, Nonnormal Limits, and the Bootstrap for Quantiles of Dependent Data

    OpenAIRE

    Sharipov, O. Sh.; Wendler, M.

    2012-01-01

    We will show under very weak conditions on differentiability and dependence that the central limit theorem for quantiles holds and that the block bootstrap is weakly consistent. Under slightly stronger conditions, the bootstrap is strongly consistent. Without the differentiability condition, quantiles might have a non-normal asymptotic distribution and the bootstrap might fail.

  14. Using the Descriptive Bootstrap to Evaluate Result Replicability (Because Statistical Significance Doesn't)

    Science.gov (United States)

    Spinella, Sarah

    2011-01-01

    As result replicability is essential to science and difficult to achieve through external replicability, the present paper notes the insufficiency of null hypothesis statistical significance testing (NHSST) and explains the bootstrap as a plausible alternative, with a heuristic example to illustrate the bootstrap method. The bootstrap relies on…

  15. Noncentral limit theorem and the bootstrap for quantiles of dependent data

    OpenAIRE

    Sharipov, Olimjon S.; Wendler, Martin

    2012-01-01

    We will show under minimal conditions on differentiability and dependence that the central limit theorem for quantiles holds and that the block bootstrap is weakly consistent. Under slightly stronger conditions, the bootstrap is strongly consistent. Without the differentiability condition, quantiles might have a non-normal asymptotic distribution and the bootstrap might fail.

  16. RANDOM QUADRATIC-FORMS AND THE BOOTSTRAP FOR U-STATISTICS

    NARCIS (Netherlands)

    DEHLING, H; MIKOSCH, T

    1994-01-01

    We study the bootstrap distribution for U-statistics with special emphasis on the degenerate case. For the Efron bootstrap we give a short proof of the consistency using Mallows' metrics. We also study the i.i.d. weighted bootstrap [GRAPHICS] where (X(i)) and (xi(i)) are two i.i.d. sequences, indepe

  17. Sidecoin: a snapshot mechanism for bootstrapping a blockchain

    OpenAIRE

    Krug, Joseph; Peterson, Jack

    2015-01-01

    Sidecoin is a mechanism that allows a snapshot to be taken of Bitcoin's blockchain. We compile a list of Bitcoin's unspent transaction outputs, then use these outputs and their corresponding balances to bootstrap a new blockchain. This allows the preservation of Bitcoin's economic state in the context of a new blockchain, which may provide new features and technical innovations.

  18. Automatic bootstrapping of a morphable face model using multiple components

    NARCIS (Netherlands)

    Haar, F.B. ter; Veltkamp, R.C.

    2009-01-01

    We present a new bootstrapping algorithm to automatically enhance a 3D morphable face model with new face data. Our algorithm is based on a morphable model fitting method that uses a set of predefined face components. This fitting method produces accurate model fits to 3D face data with noise and ho

  19. Application of bootstrap to detecting chaos in financial time series

    Science.gov (United States)

    Brzozowska-Rup, Katarzyna; Orłowski, Arkadiusz

    2004-12-01

    A moving blocks bootstrap procedure is used to investigate the dynamics of nominal exchange rates and the return rates of the US Dollar against the Polish Zloty. The problem if these financial time series exhibit chaotic behavior is undertaken. A possibility of detecting the presence of a positive Lyapunov exponent is studied.

  20. Generalized Bootstrap Method for Assessment of Uncertainty in Semivariogram Inference

    Science.gov (United States)

    Olea, R.A.; Pardo-Iguzquiza, E.

    2011-01-01

    The semivariogram and its related function, the covariance, play a central role in classical geostatistics for modeling the average continuity of spatially correlated attributes. Whereas all methods are formulated in terms of the true semivariogram, in practice what can be used are estimated semivariograms and models based on samples. A generalized form of the bootstrap method to properly model spatially correlated data is used to advance knowledge about the reliability of empirical semivariograms and semivariogram models based on a single sample. Among several methods available to generate spatially correlated resamples, we selected a method based on the LU decomposition and used several examples to illustrate the approach. The first one is a synthetic, isotropic, exhaustive sample following a normal distribution, the second example is also a synthetic but following a non-Gaussian random field, and a third empirical sample consists of actual raingauge measurements. Results show wider confidence intervals than those found previously by others with inadequate application of the bootstrap. Also, even for the Gaussian example, distributions for estimated semivariogram values and model parameters are positively skewed. In this sense, bootstrap percentile confidence intervals, which are not centered around the empirical semivariogram and do not require distributional assumptions for its construction, provide an achieved coverage similar to the nominal coverage. The latter cannot be achieved by symmetrical confidence intervals based on the standard error, regardless if the standard error is estimated from a parametric equation or from bootstrap. ?? 2010 International Association for Mathematical Geosciences.

  1. Metastability Thresholds for Anisotropic Bootstrap Percolation in Three Dimensions

    NARCIS (Netherlands)

    Van Enter, A.C.D.; Fey, A.

    2012-01-01

    In this paper we analyze several anisotropic bootstrap percolation models in three dimensions. We present the order of magnitude for the metastability thresholds for a fairly general class of models. In our proofs, we use an adaptation of the technique of dimensional reduction. We find that the orde

  2. A Bootstrap Cointegration Rank Test for Panels of VAR Models

    DEFF Research Database (Denmark)

    Callot, Laurent

    functions of the individual Cointegrated VARs (CVAR) models. A bootstrap based procedure is used to compute empirical distributions of the trace test statistics for these individual models. From these empirical distributions two panel trace test statistics are constructed. The satisfying small sample...

  3. A Statistical Mechanics Approach to Approximate Analytical Bootstrap Averages

    DEFF Research Database (Denmark)

    Malzahn, Dorthe; Opper, Manfred

    2003-01-01

    We apply the replica method of Statistical Physics combined with a variational method to the approximate analytical computation of bootstrap averages for estimating the generalization error. We demonstrate our approach on regression with Gaussian processes and compare our results with averages...

  4. Metastability thresholds for anisotropic bootstrap percolation in three dimensions

    NARCIS (Netherlands)

    Van Enter, A.C.D.; Fey, A.

    2012-01-01

    In this paper we analyze several anisotropic bootstrap percolation models in three dimensions. We present the order of magnitude for the metastability thresholds for a fairly general class of models. In our proofs, we use an adaptation of the technique of dimensional reduction. We find that the orde

  5. More on analytic bootstrap for O(N) models

    CERN Document Server

    Dey, Parijat; Sen, Kallol

    2016-01-01

    This note is an extension of a recent work on the analytical bootstrapping of $O(N)$ models. An additonal feature of the $O(N)$ model is that the OPE contains trace and antisymmetric operators apart from the symmetric-traceless objects appearing in the OPE of the singlet sector. This in addition to the stress tensor $(T_{\\mu\

  6. Bootstrapping rapidity anomalous dimension for transverse-momentum resummation

    CERN Document Server

    Li, Ye

    2016-01-01

    Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.

  7. Bootstrapping Rapidity Anomalous Dimension for Transverse-Momentum Resummation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ye [Fermilab; Zhu, Hua Xing [MIT, Cambridge, CTP

    2016-04-05

    Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.

  8. A neural network based reputation bootstrapping approach for service selection

    Science.gov (United States)

    Wu, Quanwang; Zhu, Qingsheng; Li, Peng

    2015-10-01

    With the concept of service-oriented computing becoming widely accepted in enterprise application integration, more and more computing resources are encapsulated as services and published online. Reputation mechanism has been studied to establish trust on prior unknown services. One of the limitations of current reputation mechanisms is that they cannot assess the reputation of newly deployed services as no record of their previous behaviours exists. Most of the current bootstrapping approaches merely assign default reputation values to newcomers. However, by this kind of methods, either newcomers or existing services will be favoured. In this paper, we present a novel reputation bootstrapping approach, where correlations between features and performance of existing services are learned through an artificial neural network (ANN) and they are then generalised to establish a tentative reputation when evaluating new and unknown services. Reputations of services published previously by the same provider are also incorporated for reputation bootstrapping if available. The proposed reputation bootstrapping approach is seamlessly embedded into an existing reputation model and implemented in the extended service-oriented architecture. Empirical studies of the proposed approach are shown at last.

  9. Recuperação inteligente de jurisprudência: uma avaliação do raciocínio baseado em casos aplicado a recuperação de jurisprudências no Tribunal Regional Eleitoral do Distrito Federal

    Directory of Open Access Journals (Sweden)

    Symball Rufino de Oliveira

    2011-04-01

    Full Text Available Trata-se de uma pesquisa cujo objeto é avaliar a medida de precisão de um sistema de recuperação de informação jurídica (jurisprudência que utiliza técnica de inteligência artificial conhecida como Raciocínio Baseado em Casos (RBC. Nesse modelo as jurisprudências são organizadas sob a forma de casos jurídicos concretos. O raciocínio baseado em casos tem como princípio a idéias de que um caso jurídico passado pode ser útil para resolver um problema atual, desde que exista entre eles algum grau de semelhança. Para estabelecer semelhanças entre casos atuais e passados o modelo estudado propõe o uso de cálculo de similaridade que é realizado com base na comparação de índices temáticos obtidos a partir do processo de indexação realizado por especialistas utilizando-se como apoio um tesauro jurídico. Esta pesquisa utiliza como universo as jurisprudências produzidas pelo Tribunal Regional Eleitoral do Distrito Federal. A amostra foi composta, considerando o recorte dado à pesquisa, por jurisprudências eleitorais produzidas nas eleições gerais de 2006 no Distrito Federal. Para realizar a avaliação do modelo, foi construído um protótipo do sistema de recuperação de informação baseado em casos. Em seguida, avaliou-se o protótipo quanto ao grau de precisão obtido no resultado de um conjunto de buscas. O método adotado para as avaliações foi o mesmo utilizado na Text REtrieval Conference (TREC de 2007, tarefa Legal Track. Após a coleta dos dados foi elaborado um relatório discutindo a possibilidade do sistema de recuperação de informação baseado em casos ser considerado um paradigma para a recuperação de informação jurídica eleitoral.

  10. Proposta de avanço para o método Tambor-Pulmão-Corda Simplificado aplicado em ambientes de produção sob encomenda Proposal of enhancement for the Simplified Drum-Buffer-Ropemethod applied to make-to-order production environments

    Directory of Open Access Journals (Sweden)

    Fernando Bernardi de Souza

    2010-12-01

    Full Text Available Recentes aplicações da Teoria das Restrições em Gestão de Operações têm adotado o chamado método Tambor-Pulmão-Corda Simplificado (S-DBR - Simplified Drum-Buffer-Rope como padrão para planejamento e controle da produção. Contudo, poucas são as referências bibliográficas, especialmente em periódicos nacionais e internacionais, que relatam seus principais conceitos e premissas. Este artigo se propõe a apresentar o método S-DBR para planejamento da produção e sua correspondente abordagem de controle da produção denominado Gerenciamento do Pulmão, aqui abordados em ambientes de produção sob encomenda (MTO - make to order, suas principais características, pressupostos e diferenças em relação ao método DBR clássico. É também apresentada uma proposta complementar ao método S-DBR para estabelecer promessas de entregas urgentes mantendo elevada probabilidade de entrega no prazo.Recent applications of the Theory of Constraints in operations management have adopted the method called Simplified Drum-Buffer-Rope (S-DBR as the standard for production planning and control. However, there is little information reported in the literature on this method's main concepts and premises, especially in national and international journals. This article aims to present the S-DBR method for production planning and its corresponding control approach called Buffer Management, both applied to make-to-order (MTO production environments. It also presents their main characteristics, assumptions, and differences from the classical DBR method. In addition, it includes a proposal to complement the S-DBR method for delivering urgent orders with a high probability of meeting the delivery schedule.

  11. BOOTSTRAP WAVELET IN THE NONPARAMETRIC REGRESSION MODEL WITH WEAKLY DEPENDENT PROCESSES

    Institute of Scientific and Technical Information of China (English)

    林路; 张润楚

    2004-01-01

    This paper introduces a method of bootstrap wavelet estimation in a nonparametric regression model with weakly dependent processes for both fixed and random designs. The asymptotic bounds for the bias and variance of the bootstrap wavelet estimators are given in the fixed design model. The conditional normality for a modified version of the bootstrap wavelet estimators is obtained in the fixed model. The consistency for the bootstrap wavelet estimator is also proved in the random design model. These results show that the bootstrap wavelet method is valid for the model with weakly dependent processes.

  12. Bootstrap Determination of the Co-Integration Rank in Heteroskedastic VAR Models

    DEFF Research Database (Denmark)

    Cavaliere, Giuseppe; Rahbek, Anders; Taylor, A. M. Robert

    In a recent paper Cavaliere et al. (2012) develop bootstrap implementations of the (pseudo-) likelihood ratio [PLR] co-integration rank test and associated sequential rank determination procedure of Johansen (1996). The bootstrap samples are constructed using the restricted parameter estimates of...... the underlying VAR model which obtain under the reduced rank null hypothesis. They propose methods based on an i.i.d. bootstrap re-sampling scheme and establish the validity of their proposed bootstrap procedures in the context of a co-integrated VAR model with i.i.d. innovations. In this paper we...... investigate the properties of their bootstrap procedures, together with analogous procedures based on a wild bootstrap re-sampling scheme, when time-varying behaviour is present in either the conditional or unconditional variance of the innovations. We show that the bootstrap PLR tests are asymptotically...

  13. Bootstrap Determination of the Co-integration Rank in Heteroskedastic VAR Models

    DEFF Research Database (Denmark)

    Cavaliere, Giuseppe; Rahbek, Anders; Taylor, A.M.Robert

    In a recent paper Cavaliere et al. (2012) develop bootstrap implementations of the (pseudo-) likelihood ratio [PLR] co-integration rank test and associated sequential rank determination procedure of Johansen (1996). The bootstrap samples are constructed using the restricted parameter estimates of...... the underlying VAR model which obtain under the reduced rank null hypothesis. They propose methods based on an i.i.d. bootstrap re-sampling scheme and establish the validity of their proposed bootstrap procedures in the context of a co-integrated VAR model with i.i.d. innovations. In this paper we...... investigate the properties of their bootstrap procedures, together with analogous procedures based on a wild bootstrap re-sampling scheme, when time-varying behaviour is present in either the conditional or unconditional variance of the innovations. We show that the bootstrap PLR tests are asymptotically...

  14. Avaliação de herbicidas aplicados em pré e pós-emergência na cultura da cebola (Allium cepa L. Herbicides applied in pre and pos-emergence on transplanted onion crop (Allium cepa L.

    Directory of Open Access Journals (Sweden)

    J.C. Ferreira

    1985-12-01

    Full Text Available Foram conduzidos em áreas de agricultores do Projeto de Irrigação de Bebedouro, no município de Petrolina, PE, dois experimentos de campo, onde estudouse o comportamento de diferentes herbicidas, no controle de plantas daninhas e na tolerância da cultura da cebola transpl antada. Os tratamentos foram distribuídos em blocos ao acaso com três repetições, em um Latossolo Amarelo, fase arenosa, com baixos teores de argila e matéria orgânica. No experimento I aplicaram- se oxadiazon 1,00, pentimethalin 1,25 e napropamide 1,50 kg/ha em pré-emergência, dois dias após o transplante; oxifluorfen 0,24 e 0,48 kg/ha em pós-emergência precoce, dez dias após o transplante; oxadiazon 1,00, oxadiazon 1,00 + sulfato de amônio 5,00, bentazon 0,72, acifluorfen sódico 0,32, dinoseb acetato 1,50, sethodydim 0,23, alloxydim-sodium 1,12, diclofop -metil 0,72 e bentazon 0,72 + sethoxydim 0,23 kg/ha em pós -emergência, 14 dias após o transplante. No experimento II aplicaram-se oxadiazon 1,00, oxifluorfen 0,48 e 0,96 napropamide 1,50 e 3,00 kg/ha, aos dois dias após o transplante; oxifluorfen 0,48 e 0,96, bentazon 0,72 e 1,44, acifluorfen sódico 0,27 e 0,54, dinoseb acetato 1,50 3,00 e bentazon 0,72 + sethoxydim 0,23 kg/ha , aos 14 dias após o transplante. Em avaliações realizadas aos 20 e34 dias após o transplante da cultura, respectivamente nos experimentos I e II, constataramse altos índices de controle da comunidade daninha pelos herbicidas oxadiazon e oxifluorfen. Entre os outros tratamentos, destacaram-se o acifluorfen sódico no controle de folhas largas e sethoxydim, alloxydim, napropamide, pendi methalin e a mistura bentazon + sethoxyadim no controle de gramíneas.No experimento II, dinoseb acetato e principal mente napropamide afetaram o desenvolvimento da cultu ra e comprometeram a produtividade.Two field experiments were carried out in grower's fields of the Bebedouro Irrigation Project, in Petrolina, PE, in order to study the

  15. Carfentrazone-ethyl aplicado em pós-emergência para o controle de Ipomea spp. e Commelina benghalensis na cultura da cana-de-açúcar Carfentrazone-ethyl applied in post-emergence to control Ipomoea spp. and Commelina benghalensis in sugarcane crop

    Directory of Open Access Journals (Sweden)

    P.J. Christoffoleti

    2006-01-01

    Full Text Available Este trabalho teve como objetivos determinar a eficácia e seletividade do carfentrazone-ethyl no controle de plantas daninhas na cultura da cana-de-açúcar e avaliar curvas de dose-resposta desse herbicida em Ipomoea spp. e Commelina benghalensis. Desenvolveu-se um ensaio de campo, em pós-emergência das plantas daninhas e da cultura (cv. RB72-454. O delineamento experimental utilizado foi do tipo blocos ao acaso, com os seguintes tratamentos: carfentrazone a 5, 10, 20, 30 e 50 g ha-1 e metribuzin a 2.400 g ha-1. As plantas daninhas que infestavam a área eram Ipomoea nil, I. grandifolia, I. quamoclit, Momordica charantia e C. benghalensis. As avaliações de controle visual e fitotoxicidade foram realizadas aos 15, 30 e 45 dias após a aplicação dos herbicidas. Para elaboração das curvas de dose-resposta, um experimento foi instalado em casa de vegetação, com as plantas daninhas I. nil, I. hederifolia, I. grandifolia, I. quamoclit e C. benghalensis. As doses do herbicida carfentrazone foram: 10D, 4D, 2D, D, 0,5D, 0,25D, 0,125D, 0,1D e 0,01D, em que D = 20 g ha¹. Os dados foram analisados a partir de curvas de dose-resposta de controle visual e massa fresca. No experimento de campo, observou-se excelente controle das plantas daninhas, sendo a dose de 50 g ha-1 de carfentrazone a mais eficiente. Nenhum tratamento causou danos à cana-de-açúcar. O experimento de casa de vegetação permitiu concluir que a ordem decrescente de sensibilidade das espécies de corda-de-viola ao carfentrazone-ethyl é: I. hederifolia > I. quamoclit > I. nil > I. grandifolia; e que C. benghalensis é controlada pelo carfentrazone a partir da dose de 5 g ha-1.This work aimed to evaluate the efficacy and selectivity of the herbicide carfentrazone-ethyl applied in post-emergence to control weeds in sugarcane crop and to evaluate dose-response curves of this herbicide in four species of Ipomoea spp. and Commelina benghalensis. Field experiment was carried out in

  16. Métodos de auxílio multicritério à decisão aplicados a problemas de PCP: mapeamento da produção em periódicos publicados no Brasil Multicriteria decision aid methods applied to PPC problems: a mapping of papers published in Brazilian journals

    Directory of Open Access Journals (Sweden)

    Dey Salvador Sanchez Rodriguez

    2013-03-01

    Full Text Available O presente trabalho tem por objetivo estabelecer um mapeamento da produção científica divulgada em importantes periódicos publicados no Brasil sobre a aplicação de Métodos de Auxílio Multicritério à Decisão (AMD à modelagem de problemas de Planejamento e Controle da Produção. O mapeamento contemplou 32 artigos, que foram selecionados criteriosamente, tendo como base a lista de periódicos científicos oferecida no Scielo e em importantes sociedades científicas brasileiras no âmbito da Engenharia de Produção. Os resultados permitiram indicar, entre outros aspectos, os periódicos que mais publicam neste contexto, os métodos de AMD mais usados nesta interface, os setores de produção nos quais as aplicações ocorreram e os tópicos de PCP mais abordados. Também foram destacados os aspectos de PCP que ainda carecem de estudos que envolvam métodos multicritério.The objective of this study is to map the Brazilian scientific production based on Brazilian journal publications on the implementation of Multicriteria Decision Aid (MCDA to model Production Planning and Control problems. It consisted of 32 papers that were systematically selected from journals indexed in the Scielo database and also from a list of journals suggested by major Brazilian Industrial Engineering research societies. The results revealed, among other aspects, the journals that publish the most on this topic, the most often used MCDA methods in this interface, the production sectors in which the applications took place, and the most commonly discussed PPC topics. This paper also highlights the PPC aspects that need further research including MCDA methods.

  17. Five dimensional O(N)-symmetric CFTs from conformal bootstrap

    International Nuclear Information System (INIS)

    We investigate the conformal bootstrap approach to O(N) symmetric CFTs in five dimensions with particular emphasis on the lower bound on the current central charge. The bound has a local minimum for all N>1, and in the large N limit we propose that the minimum is saturated by the critical O(N) vector model at the UV fixed point, the existence of which has been recently argued by Fei, Giombi, and Klebanov. The location of the minimum is generically different from the minimum of the lower bound of the energy–momentum tensor central charge when it exists for smaller N. To better understand the situation, we examine the lower bounds of the current central charge of O(N) symmetric CFTs in three dimensions to compare. We find the similar agreement in the large N limit but the discrepancy for smaller N with the other sectors of the conformal bootstrap

  18. A proof of fulfillment of the strong bootstrap condition

    International Nuclear Information System (INIS)

    It is shown that the kernel of the BFKL equation for the octet color state of two Reggeized gluons satisfies the strong bootstrap condition in the next-to-leading order. This condition is much more restrictive than the one obtained from the requirement of the Reggeized form for the elastic scattering amplitudes in the next-to-leading approximation. It is necessary, however, for self-consistency of the assumption of the Reggeized form of the production amplitudes in multi-Regge kinematics, which are used in the derivation of the BFKL equation. The fulfillment of the strong bootstrap condition for the kernel opens the way to a rigorous proof of the BFKL equation in the next-to-leading approximation. (orig.)

  19. Self-consistent ECCD calculations with bootstrap current

    International Nuclear Information System (INIS)

    To achieve high performance, steady-state operation in tokamaks, it is increasingly important to find the appropriate means for modifying and sustaining the pressure and magnetic shear profiles in the plasma. In such advanced scenarios, especially in the vicinity of internal transport barrier, RF induced currents have to be calculated self-consistently with the bootstrap current, thus taking into account possible synergistic effects resulting from the momentum space distortion of the electron distribution function fe. Since RF waves can cause the distribution of electrons to become non-Maxwellian, the associated changes in parallel diffusion of momentum between trapped and passing particles can be expected to modify the bootstrap current fraction; conversely, the bootstrap current distribution function can enhance the current driven by RF waves. For this purpose, a new, fast and fully implicit solver has been recently developed to carry out computations including new and detailed evaluations of the interactions between bootstrap current (BC) and Electron Cyclotron current drive (ECCD). Moreover, Ohkawa current drive (OKCD) appears to be an efficient method for driving current when the fraction of trapped particles is large. OKCD in the presence of BC is also investigated. Here, results are illustrated around projected tokamak parameters in high performance scenarios of AlcatorC-MOD. It is shown that by increasing n//, the EC wave penetration into the bulk of the electron distribution is greater, and since the resonance extends up to high p// values, this situation is the usual ECCD based on the Fisch-Boozer mechanism concerning passing particles. However, because of the close vicinity of the trapped boundary at r/a=0.7, this process is counterbalanced by the Ohkawa effect, possibly leading to a negative net current. Therefore, by injecting the EC wave in the opposite toroidal direction (n// RF by OKCD may be 70% larger than that of ECCD, with a choice of EC wave

  20. Combined RF current drive and bootstrap current in tokamaks

    International Nuclear Information System (INIS)

    By calculating radio frequency current drive (RFCD) and the bootstrap current in a consistent kinetic manner, we find synergistic effects in the total noninductive current density in tokamaks [1]. We include quasilinear diffusion in the Drift Kinetic Equation (DKE) in order to generalize neoclassical theory to highly non-Maxwellian electron distributions due to RFCD. The parallel plasma current is evaluated numerically with the help of the FASTEP Fokker-Planck code [2]. Current drive efficiency is found to be significantly affected by neoclassical effects, even in cases where only circulating electrons interact with the waves. Predictions of the current drive efficiency are made for lower hybrid and electron cyclotron wave current drive scenarios in the presence of bootstrap current. (c) 1999 American Institute of Physics

  1. Thermal energy and bootstrap current in fusion reactor plasmas

    International Nuclear Information System (INIS)

    For DT fusion reactors with prescribed alpha particle heating power Pα, plasma volume V and burn temperature i> ∼ 10 keV specific relations for the thermal energy content, bootstrap current, central plasma pressure and other quantities are derived. It is shown that imposing Pα and V makes these relations independent of the magnitudes of the density and temperature, i.e. they only depend on Pα, V and shape factors or profile parameters. For model density and temperature profiles analytic expressions for these shape factors and for the factor Cbs in the bootstrap current formula Ibs ∼ Cbs(a/R)1/2βpIp are given. In the design of next-step devices and fusion reactors, the fusion power is a fixed quantity. Prescription of the alpha particle heating power and plasma volume results in specific relations which can be helpful for interpreting computer simulations and for the design of fusion reactors. (author) 5 refs

  2. Bootstrap bound for conformal multi-flavor QCD on lattice

    Science.gov (United States)

    Nakayama, Yu

    2016-07-01

    The recent work by Iha et al. shows an upper bound on mass anomalous dimension γ m of multi-flavor massless QCD at the renormalization group fixed point from the conformal bootstrap in SU( N F ) V symmetric conformal field theories under the assumption that the fixed point is realizable with the lattice regularization based on staggered fermions. We show that the almost identical but slightly stronger bound applies to the regularization based on Wilson fermions (or domain wall fermions) by studying the conformal bootstrap in SU( N f ) L × SU( N f ) R symmetric conformal field theories. For N f = 8, our bound implies γ m < 1 .31 to avoid dangerously irrelevant operators that are not compatible with the lattice symmetry.

  3. A bootstrap lunar base: Preliminary design review 2

    Science.gov (United States)

    1987-01-01

    A bootstrap lunar base is the gateway to manned solar system exploration and requires new ideas and new designs on the cutting edge of technology. A preliminary design for a Bootstrap Lunar Base, the second provided by this contractor, is presented. An overview of the work completed is discussed as well as the technical, management, and cost strategies to complete the program requirements. The lunar base design stresses the transforming capabilities of its lander vehicles to aid in base construction. The design also emphasizes modularity and expandability in the base configuration to support the long-term goals of scientific research and profitable lunar resource exploitation. To successfully construct, develop, and inhabit a permanent lunar base, however, several technological advancements must first be realized. Some of these technological advancements are also discussed.

  4. Bootstrap bound for conformal multi-flavor QCD on lattice

    CERN Document Server

    Nakayama, Yu

    2016-01-01

    The recent work by Iha et al shows an upper bound on mass anomalous dimension $\\gamma_m$ of multi-flavor massless QCD at the renormalization group fixed point from the conformal bootstrap in $SU(N_F)_V$ symmetric conformal field theories under the assumption that the fixed point is realizable with the lattice regularization based on staggered fermions. We show that the almost identical but slightly stronger bound applies to the regularization based on Wilson fermions (or domain wall fermions) by studying the conformal bootstrap in $SU(N_f)_L \\times SU(N_f)_R$ symmetric conformal field theories. For $N_f=8$, our bound implies $\\gamma_m < 1.31$ to avoid dangerously irrelevant operators that are not compatible with the lattice symmetry.

  5. Conformal bootstrap: non-perturbative QFT's under siege

    CERN Document Server

    CERN. Geneva

    2016-01-01

    [Exceptionally in Council Chamber] Originally formulated in the 70's, the conformal bootstrap is the ambitious idea that one can use internal consistency conditions to carve out, and eventually solve, the space of conformal field theories. In this talk I will review recent developments in the field which have boosted this program to a new level. I will present a method to extract quantitative informations in strongly-interacting theories, such as 3D Ising, O(N) vector model and even systems without a Lagrangian formulation. I will explain how these techniques have led to the world record determination of several critical exponents. Finally, I will review exact analytical results obtained using bootstrap techniques.

  6. Entrenamiento oclusivo aplicado a procesos de rehabilitación

    OpenAIRE

    Scavo, Matías

    2013-01-01

    El entrenamiento en oclusión vascular es un campo de las ciencias aplicadas al ejercicio en continua investigación. En este sentido, han aparecido diversos trabajos científicos en los últimos años aplicados al campo de la recuperación de lesiones. En la presentación se describe la metodología del entrenamiento en oclusión vascular y las adaptaciones tanto agudas como crónicas, así como la importancia de las vías de señalización sobre la síntesis proteica. La evidencia actual posiciona a dicho...

  7. Bootstrapping a Five-Loop Amplitude from Steinmann Relations

    CERN Document Server

    Caron-Huot, Simon; McLeod, Andrew; von Hippel, Matt

    2016-01-01

    The analytic structure of scattering amplitudes is restricted by Steinmann relations, which enforce the vanishing of certain discontinuities of discontinuities. We show that these relations dramatically simplify the function space for the hexagon function bootstrap in planar maximally supersymmetric Yang-Mills theory. Armed with this simplification, along with the constraints of dual conformal symmetry and Regge exponentiation, we obtain the complete five-loop six-particle amplitude.

  8. Directed rigidity and bootstrap percolation in (1+1) dimensions

    OpenAIRE

    de Menezes, Marcio Argollo; Moukarzel, Cristian F.

    1999-01-01

    We study directed rigidity percolation (equivalent to directed bootstrap percolation) on three different lattices: square, triangular, and augmented triangular. The first two of these display a first-order transition at p=1, while the augmented triangular lattice shows a continuous transition at a non-trivial p_c. On the augmented triangular lattice we find, by extensive numerical simulation, that the directed rigidity percolation transition belongs to the same universality class as directed ...

  9. Bootstrapping an empty repertoire of experience: the design case

    OpenAIRE

    Saliou, Philippe; Ribaud, Vincent

    2009-01-01

    Performing good design is a difficult task. To take up this challenge, practitioners rely on their repertoire of experience. Students, however, do not have any such repertoire. We propose an approach aimed at bootstrapping the repertoire. The approach is generally accomplished in two steps: tailoring the activity - acquiring a minimal structure through a deductive approach, then initializing the repertoire through an inductive approach; and performing the activity - to begin filling the reper...

  10. Educational efficiency in a dea-bootstrap approach

    OpenAIRE

    Francesca Giambona; Erasmo Vassallo; Elli Vassiliadis

    2010-01-01

    We use the PISA 2006 results to analyse the students' proficiencies in 24 European Countries with regard to two indexes that represent the educational resources available at home and the family background of students. Many factors affect the proficiencies and therefore, using a DEA-bootstrap method, we intend to measure the efficiency of the European educational systems as capability to ensure high students' competencies despite adverse conditions about the educational resources available in ...

  11. 'Bootstrap' charging of surfaces composed of multiple materials

    Science.gov (United States)

    Stannard, P. R.; Katz, I.; Parks, D. E.

    1981-01-01

    The paper examines the charging of a checkerboard array of two materials, only one of which tends to acquire a negative potential alone, using the NASA Charging Analyzer Program (NASCAP). The influence of the charging material's field causes the otherwise 'non-charging' material to acquire a negative potential due to the suppression of its secondary emission ('bootstrap' charging). The NASCAP predictions for the equilibrium potential difference between the two materials are compared to results based on an analytical model.

  12. Higgs Critical Exponents and Conformal Bootstrap in Four Dimensions

    DEFF Research Database (Denmark)

    Antipin, Oleg; Mølgaard, Esben; Sannino, Francesco

    2015-01-01

    We investigate relevant properties of composite operators emerging in nonsupersymmetric, four-dimensional gauge-Yukawa theories with interacting conformal fixed points within a precise framework. The theories investigated in this work are structurally similar to the standard model of particle int...... bootstrap results are then compared to precise four dimensional conformal field theoretical results. To accomplish this, it was necessary to calculate explicitly the crossing symmetry relations for the global symmetry group SU($N$)$\\times$SU($N$)....

  13. Spectrum of local boundary operators from boundary form factor bootstrap

    OpenAIRE

    Szots, M.; Takacs, G.

    2007-01-01

    Using the recently introduced boundary form factor bootstrap equations, we map the complete space of their solutions for the boundary version of the scaling Lee-Yang model and sinh-Gordon theory. We show that the complete space of solutions, graded by the ultraviolet behaviour of the form factors can be brought into correspondence with the spectrum of local boundary operators expected from boundary conformal field theory, which is a major evidence for the correctness of the boundary form fact...

  14. Bootstrap and the physical values of $\\pi N$ resonance parameters

    OpenAIRE

    Semenov-Tian-Shansky, Kirill M.; Vereshagin, Alexander V.; Vereshagin, Vladimir V.

    2007-01-01

    This is the 6th paper in the series developing the formalism to manage the effective scattering theory of strong interactions. Relying on the theoretical scheme suggested in our previous publications we concentrate here on the practical aspect and apply our technique to the elastic pion-nucleon scattering amplitude. We test numerically the pion-nucleon spectrum sum rules that follow from the tree level bootstrap constraints. We show how these constraints can be used to estimate the tensor and...

  15. Study and Integrate Bootstrap 3 for OpixManager

    OpenAIRE

    Tapani, Zhejia

    2010-01-01

    ABSTRACT This bachelor thesis is about how to study and integrate Bootstrap 3 into OpixManager. The purpose is to improve user interface of OpixManager application. OpixManager is constructed by using CodeIgniter and Model-View-Controller (MVC) framework. OpixManager application is for project management. It includes staff augmentation, customer management, report management and so on. It is to support both scrum and traditional software development process. There are two major parts...

  16. Bootstrap-Based Regularization for Low-Rank Matrix Estimation

    OpenAIRE

    Josse, Julie; Wager, Stefan

    2014-01-01

    We develop a flexible framework for low-rank matrix estimation that allows us to transform noise models into regularization schemes via a simple bootstrap algorithm. Effectively, our procedure seeks an autoencoding basis for the observed matrix that is stable with respect to the specified noise model; we call the resulting procedure a stable autoencoder. In the simplest case, with an isotropic noise model, our method is equivalent to a classical singular value shrinkage estimator. For non-iso...

  17. Addressing the P2P Bootstrap Problem for Small Networks

    OpenAIRE

    Wolinsky, David Isaac; Juste, Pierre St.; Boykin, P. Oscar; Figueiredo, Renato

    2010-01-01

    P2P overlays provide a framework for building distributed applications consisting of few to many resources with features including self-configuration, scalability, and resilience to node failures. Such systems have been successfully adopted in large-scale services for content delivery networks, file sharing, and data storage. In small-scale systems, they can be useful to address privacy concerns and for network applications that lack dedicated servers. The bootstrap problem, finding an existi...

  18. A conformal bootstrap approach to critical percolation in two dimensions

    CERN Document Server

    Picco, Marco; Santachiara, Raoul

    2016-01-01

    We study four-point functions of critical percolation in two dimensions, and more generally of the Potts model. We propose an exact ansatz for the spectrum: an infinite, discrete and non-diagonal combination of representations of the Virasoro algebra. Based on this ansatz, we compute four-point functions using a numerical conformal bootstrap approach. The results agree with Monte-Carlo computations of connectivities of random clusters.

  19. A Bootstrap Cointegration Rank Test for Panels of VAR Models

    OpenAIRE

    Callot, Laurent

    2010-01-01

    This paper proposes a sequential procedure to determine the common cointegration rank of panels of cointegrated VARs. It shows how a panel of cointegrated VARs can be transformed in a set of independent individual models. The likelihood function of the transformed panel is the sum of the likelihood functions of the individual Cointegrated VARs (CVAR) models. A bootstrap based procedure is used to compute empirical distributions of the trace test statistics for these individual models. From th...

  20. Bootstrapping Security Policies for Wearable Apps Using Attributed Structural Graphs

    OpenAIRE

    González-Tablas, Ana I.; Tapiador, Juan E.

    2016-01-01

    We address the problem of bootstrapping security and privacy policies for newly-deployed apps in wireless body area networks (WBAN) composed of smartphones, sensors and other wearable devices. We introduce a framework to model such a WBAN as an undirected graph whose vertices correspond to devices, apps and app resources, while edges model structural relationships among them. This graph is then augmented with attributes capturing the features of each entity together with user-defined tags. We...

  1. Current profile control for high bootstrap current operation in ITER

    International Nuclear Information System (INIS)

    For the achievement of steady-state fusion power plant, non-inductively current-driven plasma operation should be maintained in tokamak fusion reactors. Total non-inductive current is a summation of bootstrap current proportional to the plasma pressure gradient and externally driven non-inductive current such as neutral beam driven current. Especially in order to establish a commercial reactor, it is necessary to reduce the amount of external current-drive power and to maintain the majority of the plasma current with bootstrap current. Burning plasma has high autonomy, so the change in current density profile including changes in particle and heat transports should be checked. In this study time-evolution analysis of the current density profile for burning plasmas in the ITER machine has been conducted by using 2.0-dimensional equilibrium, 1.5-dimensional-transport code (TOTAL code). Here current-diffusive ballooning mode model was adopted as a heat transport model. It is concluded that external current-drive is required both in the center and near the periphery of the plasma in order to maintain steady-state profiles of temperature and density with high bootstrap current fraction. (author)

  2. Quantitative evaluation of PET image using event information bootstrap

    Science.gov (United States)

    Song, Hankyeol; Kwak, Shin Hye; Kim, Kyeong Min; Kang, Joo Hyun; Chung, Yong Hyun; Woo, Sang-Keun

    2016-04-01

    The purpose of this study was to enhance the effect in the PET image quality according to event bootstrap of small animal PET data. In order to investigate the time difference condition, realigned sinograms were generated from randomly sampled data set using bootstrap. List-mode data was obtained from small animal PET scanner for Ge-68 30 sec, Y-90 20 min and Y-90 60 min. PET image was reconstructed by Ordered Subset Expectation Maximization(OSEM) 2D with the list-mode format. Image analysis was investigated by Signal to Noise Ratio(SNR) of Ge-68 and Y-90 image. Non-parametric resampled PET image SNR percent change for the Ge-68 30 sec, Y-90 60 min, and Y-90 20 min was 1.69 %, 7.03 %, and 4.78 %, respectively. SNR percent change of non-parametric resampled PET image with time difference condition was 1.08 % for the Ge-68 30 sec, 6.74 % for the Y-90 60 min and 10.94 % for the Y-90 29 min. The result indicated that the bootstrap with time difference condition had a potential to improve a noisy Y-90 PET image quality. This method should be expected to reduce Y-90 PET measurement time and to enhance its accuracy.

  3. Truncatable bootstrap equations in algebraic form and critical surface exponents

    CERN Document Server

    Gliozzi, Ferdinando

    2016-01-01

    We describe examples of drastic truncations of conformal bootstrap equations encoding much more information than that obtained by a direct numerical approach. A three-term truncation of the four point function of a free scalar in any space dimensions provides algebraic identities among conformal block derivatives which generate the exact spectrum of the infinitely many primary operators contributing to it. In boundary conformal field theories, we point out that the appearance of free parameters in the solutions of bootstrap equations is not an artifact of truncations, rather it reflects a physical property of permeable conformal interfaces which are described by the same equations. Surface transitions correspond to isolated points in the parameter space. We are able to locate them in the case of 3d Ising model, thanks to a useful algebraic form of 3d boundary bootstrap equations. It turns out that the low-lying spectra of the surface operators in the ordinary and the special transitions of 3d Ising model form...

  4. Comparison Of Modified Bootstrap And Conventional Sensitometry In Medical Radiography

    Science.gov (United States)

    Bednarek, Daniel R.; Rudin, Stephen

    1980-08-01

    A new modified bootstrap approach to sensitometry is presented which provides H and D curves that show almost exact agreement with those obtained using conventional methods. Two bootstrap techniques are described; both involve a combination of inverse-square and step-ped wedge modulation of the radiation field and provide intensity-scale sensitometric curves as appropriate for medical radiography. H and D curves obtained with these modified techniques are compared with those obtained for screen-film combinations using inverse-square sensitometry as well as with those obtained for direct x-ray film using time-scale sensitometry. The stepped-wedge of the Wisconsin X-Ray Test Cassette was used in the boot-strap approach since it provides sufficient exposure latitude to encompass the useful den-sity range of medical x-ray film. This approach makes radiographic sensitometry quick and convenient, allowing accurate characteristic curves to be obtained for any screen-film cassette using standard diagnostic equipment.

  5. Padronização do teste imunoalérgico aplicado ao diagnóstico da tuberculose e micobacterioses em suínos (Sus scrofa experimentalmente sensibilizados com suspensões oleosas de Mycobacterium bovis ou M. avium inativados

    Directory of Open Access Journals (Sweden)

    Flávia C.S. Oliveira

    2014-02-01

    Full Text Available Foi investigado o valor diagnóstico da resposta alérgica cutânea em leitões experimentalmente sensibilizados, pela via intramuscular, com suspensões oleosas de Mycobacterium bovis ou M. avium inativados pelo calor.Foram utilizados 91 animais, divididos em quatro grupos: grupos A e B, cada um com 25 indivíduos, grupos C e D com 21 e 20 indivíduos respectivamente, balanceando-se as características de raça, linhagem, faixa etária e sexo. Aos 30 dias de idade, todos os animais foram submetidos a uma triagem com a aplicação de tuberculina PPD bovina, pela via intradérmica na base da orelha e não houve qualquer tipo de reação. Decorridos 60 dias do teste tuberculínico de triagem, o grupo A recebeu injeção intramuscular de 0,5 mL de uma suspensão oleosa de M. avium estirpe D4; o grupo B recebeu 0,5 mL de uma suspensão oleosa de M. bovis estirpe AN5; o grupo C (controle I, recebeu 0,5 mL do adjuvante oleoso; e o grupo D (controle II, recebeu 0,5 mL de solução fisiológica. Após 30 dias da sensibilização foi realizada a prova de tuberculinização comparativa com reação medida pela variação da espessura da pele com cutímetro de mola às 0h, 24h, 48h e 72h, após a aplicação das tuberculinas. No teste comparativo, lido às 48 ou 72 horas, a reação foi considerada negativa quando a diferença das reações entre o PPD bovino e o PPD aviário foi menor que 6,7 mm; suspeito ou inconclusivo quando a diferença se situou na faixa de 6,7 a 7,5 mm; e positiva de acordo com o tipo de PPD, considerando-se tuberculose para PPD M. bovis e micobacteriose para PPD M. avium, quando a diferença da reação foi superior a 7,5 mm.

  6. MINERAÇÃO DE TEXTO APLICADO A LAUDOS MÉDICOS: UMA ANÁLISE BIBLIOMÉTRICA

    Directory of Open Access Journals (Sweden)

    Fábio Barbosa BATISTA

    2015-12-01

    Full Text Available Este trabalho refere-se em uma análise bibliométrica abordando a aplicação do estudo de mineração de textos em laudos médicos. O objetivo do artigo é a realização de um levantamento bibliométrico que foi realizado através do Portal Periódico Capes. A pesquisa foi realizada tendo como palavra chave de pesquisa “Mining Text Information Extraction Medical Reports”. A pesquisa inicial somente utilizando a palavra chave, obteve 1.190 registros, sendo 1.636 resultados refinado por nível superior de periódicos revisados por pares. Foram aplicados refinamentos diante dos resultados encontrados, assim resultando em 47 artigos, conforme é descrito no decorrer do trabalho. Ao final da análise completa dos artigos selecionados, foram considerados 10 trabalhos para compor o núcleo de partida para a pesquisa, análise esta que, demonstra e comprovam as aplicações efetivas e satisfatórias da utilização da mineração de texto aplicadas a laudos médicos, oportunizando uma discussão positiva da utilização da técnica de mineração de texto na área da saúde.

  7. Using minimum bootstrap support for splits to construct confidence regions for trees

    Directory of Open Access Journals (Sweden)

    Edward Susko

    2006-01-01

    Full Text Available Many of the estimated topologies in phylogenetic studies are presented with the bootstrap support for each of the splits in the topology indicated. If phylogenetic estimation is unbiased, high bootstrap support for a split suggests that there is a good deal of certainty that the split actually is present in the tree and low bootstrap support suggests that one or more of the taxa on one side of the estimated split might in reality be located with taxa on the other side. In the latter case the follow-up questions about how many and which of the taxa could reasonably be incorrectly placed as well as where they might alternatively be placed are not addressed through the presented bootstrap support. We present here an algorithm that finds the set of all trees with minimum bootstrap support for their splits greater than some given value. The output is a ranked list of trees, ranked according to the minimum bootstrap supports for splits in the trees. The number of such trees and their topologies provides useful supplementary information in bootstrap analyses about the reasons for low bootstrap support for splits. We also present ways of quantifying low bootstrap support by considering the set of all topologies with minimum bootstrap greater than some quantity as providing a confidence region of topologies. Using a double bootstrap we are able to choose a cutoff so that the set of topologies with minimum bootstrap support for a split greater than that cutoff gives an approximate 95% confidence region. As with bootstrap support one advantage of the methods is that they are generally applicable to the wide variety of phylogenetic estimation methods.

  8. Paracetamol e dipirona por via endovenosa aplicados à analgesia pós-operatória de pacientes pediátricos submetidos à amigdelectomia em hospital-dia: um estudo prospectivo, randomizado, duplo-cego, placebo controlado Intravenous paracetamol and dipyrone for postoperative analgesia after day-case tonsillectomy in children: a prospective, randomized, double blind, placebo controlled study

    Directory of Open Access Journals (Sweden)

    Aysu Inan Kocum

    2013-02-01

    Full Text Available O manejo da dor pós-amigdelectomia pode ser feito com uma série de medicamentos. OBJETIVO: O presente estudo duplo-cego placebo controlado pretendeu avaliar a eficácia de paracetamol e dipirona administrados por via endovenosa na analgesia de pacientes pediátricos pós-amigdelectomia. MÉTODO: Cento e vinte crianças com idades entre três e seis anos submetidas à amigdelectomia com ou sem adenoidectomia e/ou entubação foram randomizadas para receber infusões de paracetamol (15 mg/kg, dipirona (15 mg/kg ou placebo (0,9% NaCl durante a cirurgia. As avaliações foram executadas com 0,25, 0,50, 1, 2, 4, 6h de pós-operatório. Petidina 0,25 mg/kg foi utilizada como analgésico de resgate. Dose acumulada de petidina foi o desfecho primário. Medições de intensidade da dor, alívio da dor, nível de sedação, náusea e vômitos, hemorragia no pós-operatório e outros efeitos adversos foram anotados. RESULTADOS: Nenhuma diferença significativa foi encontrada na dose acumulada de petidina entre os grupos paracetamol e dipirona. A dose acumulada de petidina foi significativamente menor nos grupos paracetamol e dipirona em comparação ao grupo placebo. Nenhuma diferença significativa foi observada entre os escores de dor no pós-operatório dos grupos durante o estudo. CONCLUSÃO: Paracetamol endovenoso tem eficácia analgésica semelhante à da dipirona endovenosa; ambos ajudam a reduzir a necessidade de opioides na analgesia pós-operatória de pacientes pediátricos submetidos à amigdelectomia em hospital-dia.Tonsillectomy is associated with severe postoperative pain for which, several drugs are employed for management. OBJECTIVE: In this double-blind, placebo-controlled study we aimed to evaluate the efficacy of intravenous paracetamol and dipyrone when used for post-tonsillectomy analgesia in children. METHOD: 120 children aged 3-6 yr, undergoing tonsillectomy with or without adenoidectomy and/or ventilation tube insertion were

  9. Método de impregnação química aplicado em tubos microporosos e membranas tubulares para a microfiltração de emulsões e suspensões de bactérias Method of chemical impregnation applied to microporous tubes and tubular membranes for the microfiltration of emulsions and bacteria suspensions

    Directory of Open Access Journals (Sweden)

    R. Del Colle

    2008-03-01

    Full Text Available Uma técnica de impregnação química via solução de precursor foi desenvolvida para formação de filmes finos em tubos microporosos e membranas tubulares. O desempenho desta técnica foi analisado no processo de microfiltração de emulsões (óleo vegetal/água e de suspensões de bactérias (Escherichia coli do soro residual do processamento de queijo. Os tubos microporosos (tamanho nominal 0,5 µm foram impregnados com solução precursora de zircônia (e calcinados a 600 e 900 ºC afim de influenciar na melhora do processo de desemulsificação e as membranas cerâmicas (tamanho nominal entre 0,8 µm e 1,2 µm foram impregnadas com precursor (e calcinadas a 600 °C para formação de prata metálica, para agir como bactericida na suspensão residuária de bactérias da indústria de queijo. O meio poroso impregnado foi caracterizado por meio de microscopia eletrônica de varredura. Os resultados da análise do permeado para valores do teor orgânico de carbono são respectivos ao tratamento de emulsões; o valor da contagem de bactérias via análise de plaqueamento é respectivo ao tratamento de suspensão de bactérias. Os resultados foram analisados e discutidos em função do desempenho e da influência da impregnação quanto à presença de zircônia ou prata para cada aplicação.A technique of chemical impregnation by precursor solution was developed for the formation of thin films in microporous tubes and tubular membranes. The performance of this technique was analyzed by the microfiltration process of emulsions (vegetable oil/water and bacteria suspensions (Escherichia coli of the whey of milk of cheese processing. The microporous tubes (nominal pore size 0.5 µm were impregnated with a precursor zirconia solution and calcined at 600 and 900 ºC to influence the improvement of the demulsification process. Ceramic membranes (nominal pore size between 0.8 µm and 1.2 µm were impregnated with a silver precursor and calcined at

  10. Methodological proposal for identification and evaluation of environmental aspects and impacts of nuclear facilities of IPEN, Sao Paulo, SP, Brazil: a case study applied to the Nuclear Fuel Center; Proposta metodologica para a identificacao e avaliacao de aspectos e impactos ambientais em instalacoes nucleares do IPEN: estudo de caso aplicado ao Centro do Combustivel Nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Luis Antonio Terribile de

    2013-07-01

    This work presents an application of Failure Mode Effect Analysis (FMEA) to the process of identification of environmental aspects and impacts as a part of implementation and maintenance of an Environmental Management System (EMS) in accordance with the NBR ISO 14001 standard. Also, it can contribute, as a complement, to the evaluation and improvement of safety of the installation focused. The study was applied to the Nuclear Fuel Center (CCN) of Nuclear and Energy Research Institute (IPEN), situated at the Campus of University of Sao Paulo, Brazil. The CCN facility has the objective of promoting scientific research and of producing nuclear fuel elements for the IEA-R1 Research Reactor. To identify the environmental aspects of the facility activities, products, and services, a systematic data collection was carried out by means of personal interviews, documents, reports and operation data records consulting. Furthermore, the processes and their interactions, failure modes, besides their causes and effects to the environment, were identified. As a result of a careful evaluation of these causes it was possible to identify and to classify the major potential environmental impacts, in order to set up and put in practice an Environmental Management System for the installation under study. The results have demonstrated the validity of the FMEA application to nuclear facility processes, identifying environmental aspects and impacts, whose controls are critical to achieve compliance with the environmental requirements of the Integrated Management System of IPEN. It was demonstrated that the methodology used in this work is a powerful management tool for resolving issues related to the conformity with applicable regulatory and legal requirements of the Brazilian Nuclear Energy Commission (CNEN) and the Brazilian Institute of Environment (IBAMA). (author)

  11. Optimization of bootstrap current in a large helical system with L = 2

    International Nuclear Information System (INIS)

    Neoclassical bootstrap currents in the banana and plateau regions are evaluated for an L = 2 large helical system with the major radius of 5 m. Various vacuum magnetic field configurations are invoked to optimize the bootstrap current. In the banana region shifting the magnetic axis and shaping magnetic surfaces have remarkable effects on the bootstrap current and it is clarified that a small outward shift of the magnetic axis and vertically elongated magnetic surfaces are favourable to reduce the bootstrap current. On the contrary, the bootstrap current in the plateau region depends strongly on the toroidal pitch number of helical winding coils but shifting the axis and shaping magnetic surfaces are not effective. The magnitude of bootstrap current is estimated for plasmas in the large helical system predicted by a one dimensional transport code. (author)

  12. Better confidence intervals for left censored data using bias corrected bootstrap method

    International Nuclear Information System (INIS)

    Estimation of the 95% confidence intervals of the population parameters of small sized (say <= 30) environmental data samples under conventional statistical methodologies are error prone because the probability density function associated with the specified data sets, most of the times, is questionable. Therefore, in instances when the distribution of a statistic is unknown, nonparametric methods such as bootstrap override the conventional ones. The nonparametric (percentile) bootstrap method has been used to evaluate the confidence intervals of the mean. This paper describes the application of bias-corrected percentile bootstrap method that yields better confidence intervals than the percentile bootstrap method. An inter-comparative study of the two methods is also carried out. A case study with air activity data recorded from a specific Indian nuclear power plant is presented to support the superiority of bias corrected bootstrap method over the percentile bootstrap method and the conventional students -t method. (author)

  13. Asal Bileşenler Analizine Bootstrap Yaklaşımı

    OpenAIRE

    AKTÜKÜN, Dr. Aylin

    2011-01-01

    Bu çalışmada, bootstrap yöntemlerin asal bileşenler analizine uygulanma sürecini sunduk. Hipotetik bir veri ile asal bileşenler analizinde başvurulan bazı güven aralıklarının bootstrap yöntemlerle nasıl gerçekleştirilebileceğini gösterdik. Makaledeki tüm bootstrap süreçleri Mathematica dilinde yazdığımız bir programla gerçekleştirdik. Anahtar Kelimeler: Asal bileşenler analizi, Bootstrap, Bootstrap kantiller, Bootstrap Güven Aralıkları, Mathematica.  ABSRACT In this paper, we apply ...

  14. Comparação entre o tratamento farmacológico aplicado em crianças de zero a cinco anos atendidas em uma unidade de emergência e as diretrizes do III Consenso Brasileiro no Manejo da Asma Comparison between the drug treatment used in children up to five years of age treated in an emergency room and the guidelines established in the III Brazilian Consensus on Asthma Management

    Directory of Open Access Journals (Sweden)

    Ana Paula Ochoa Santos

    2007-02-01

    Full Text Available OBJETIVO: Avaliar o manejo da crise asmática em crianças de zero a cinco anos atendidas em uma unidade de emergência pediátrica da região metropolitana do Recife (PE e verificar se a condução da crise asmática pode interferir no tempo de permanência da criança no serviço de emergência. MÉTODOS: Estudo de natureza descritiva exploratória, abordagem quantitativa e corte transversal. Envolveu 246 crianças em crise asmática de uma unidade de emergência, tendo sido avaliada a conduta utilizada, a conduta preconizada pelo III Consenso Brasileiro no Manejo da Asma e o tempo de permanência da criança na emergência. RESULTADOS: Os fármacos foram utilizados de acordo com o preconizado em 69 atendimentos (28,1%. As doses dos fármacos foram concordantes com as preconizadas em 34 atendimentos (13,8% e os procedimentos de nebulização em 33 (13,4%. Não houve associação entre as condutas utilizadas e o tempo de permanência no serviço. Após aplicação do modelo de regressão, observou-se que crianças com asma de classificação persistente leve e intermitente tiveram um risco ajustado, respectivamente, de quatro e quinze vezes maior de permanecerem no serviço de emergência por tempo insuficiente para avaliação da resposta ao tratamento da crise, conforme o preconizado pelo consenso. CONCLUSÃO: Apesar de o manejo preconizado pelo consenso encontrar barreiras de aplicação como pouca familiaridade da equipe multidisciplinar com as diretrizes e ausência de recursos materiais e terapêuticos preconizados, a repercussão no tempo de permanência esteve relacionada a fatores classificatórios da doença.OBJECTIVE: To evaluate the management of asthma attacks in children up to five years of age treated in the pediatric emergency room of a hospital in the metropolitan area of the city of Recife, Brazil, as well as to determine whether the way in which asthma attacks are managed can influence the duration of emergency room visits

  15. Transport simulation of a large-bootstrap-current Tokamak plasma driven by the ohmic seed current

    International Nuclear Information System (INIS)

    A large-bootstrap-current tokamak plasma driven by the ohmic seed current has been studied for inductively-operated ultra-long-pulse tokamak fusion reactors. The safety factor profile with the negative magnetic shear has been demonstrated only by the combination of the ohmic and bootstrap currents, by adjusting the density profile, and the bootstrap current fraction more than 80% is realized with the help of the increased q(0) value. 7 refs., 4 figs., 1 tab

  16. On variance estimation and a goodness-of-fit test using the bootstrap method

    OpenAIRE

    Amiri, Saeid

    2009-01-01

    This thesis deals with the study of variance estimation using the bootstrap method, including the problem of choosing between nonparametric and parametric bootstrap methods. Paper I compares the two approaches, determines which method is preferable and analyses the accuracy of the approximations. The underlying concept of parametric bootstrap is based on the assumption of correct choice of parametric distribution. Paper II therefore considers goodness-of-fit tests and presents a new test base...

  17. Full Hirshman-Sigmar model for bootstrap current estimate in the ETE small aspect ratio Tokamak

    International Nuclear Information System (INIS)

    An estimate of the bootstrap current through the full Hirshman-Sigmar model, which is the most accurate available for thermal plasmas up to now, will be carried out the ETE tokamak. These results will be compared to previous calculations performed with the single-ion collisionless Hirshman model in order to check possible limitations imposed by this model on the bootstrap current estimate. The dependences of the bootstrap current profile upon the plasma parameters will also be briefly illustrated. (author)

  18. Performance of the bootstrap for DEA estimators and iterating the principle

    OpenAIRE

    Simar, Léopold; Wilson, Paul

    2000-01-01

    This paper further examines the bootstrap method proposed by Simar and Wilson (1998) for DEA efficiency estimators. Some simplifications are provided, and we provide Monte Carlo evidence on the coverage probabilities of confidence intervals estimated by the method. In addition, we provide similar evidence for confidence intervals estimate with the so-called naive bootstrap, which is known to be inconsistent in the DEA setting. Finally, we propose an interated version of the bootstrap which ma...

  19. Higher-order accuracy of multiscale-double bootstrap for testing regions

    OpenAIRE

    Shimodaira, Hidetoshi

    2013-01-01

    We consider hypothesis testing for the null hypothesis being represented as an arbitrary-shaped region in the parameter space. We compute an approximate p-value by counting how many times the null hypothesis holds in bootstrap replicates. This frequency, known as bootstrap probability, is widely used in evolutionary biology, but often reported as biased in the literature. Based on the asymptotic theory of bootstrap confidence intervals, there have been some new attempts for adjusting the bias...

  20. A PARAMETRIC BOOTSTRAP USING THE FIRST FOUR
    MOMENTS OF THE RESIDUALS

    OpenAIRE

    Treyens, Pierre-Eric

    2007-01-01

    We consider linear regression models and we suppose that disturbances are either Gaussian or non Gaussian. Until now, within the framework of the bootstrap, we thought that the error in rejection probability (ERP) had the same rate of convergence with the parametric bootstrap or the nonparametric bootstrap. For linear data generating processes (DGP) we show in this paper that this assertion is false if skewness and/or kurtosis coefficients of the distribution of the disturbances are nonnull. ...

  1. Bootstrap Co-integration Rank Testing: The Effect of Bias-Correcting Parameter Estimates

    OpenAIRE

    Cavaliere, Giuseppe; Taylor, A. M. Robert; Trenkler, Carsten

    2013-01-01

    In this paper we investigate bootstrap-based methods for bias-correcting the first-stage parameter estimates used in some recently developed bootstrap implementations of the co-integration rank tests of Johansen (1996). In order to do so we adapt the framework of Kilian (1998) which estimates the bias in the original parameter estimates using the average bias in the corresponding parameter esti- mates taken across a large number of auxiliary bootstrap replications. A number of possible imp...

  2. Building Confidence Intervals with Block Bootstraps for the Variance Ratio Test of Predictability

    OpenAIRE

    Eduardo José Araújo Lima; Benjamin Miranda Tabak

    2007-01-01

    This paper compares different versions of the multiple variance ratio test based on bootstrap techniques for the construction of empirical distributions. It also analyzes the crucial issue of selecting optimal block sizes when block bootstrap procedures are used, by applying the methods developed by Hall et al. (1995) and by Politis and White (2004). By comparing the results of the different methods using Monte Carlo simulations, we conclude that methodologies using block bootstrap methods pr...

  3. On the Impact of Bootstrap in Survey Sampling and Small-Area Estimation

    OpenAIRE

    Lahiri, P.

    2003-01-01

    Development of valid bootstrap procedures has been a challenging problem for survey samplers for the last two decades. This is due to the fact that in surveys we constantly face various complex issues such as complex correlation structure induced by the survey design, weighting, imputation, small-area estimation, among others. In this paper, we critically review various bootstrap methods developed to deal with these challenging issues. We discuss two applications where the bootstrap has been ...

  4. Mecanismos de microrregulação aplicados por operadoras de planos de saúde sobre hospitais privados Mecanismos de microregulación aplicados por operadoras de seguros de salud en hospitales privados Mechanisms of microregulation of private hospitals by health plan operators

    OpenAIRE

    Maria Alicia Domínguez Ugá; Miguel Murat Vasconcellos; Sheyla Maria Lemos Lima; Margareth Crisóstomo Portela; Silvia Gerschman

    2009-01-01

    OBJETIVO: Analisar os mecanismos de microrregulação aplicados pelas operadoras de planos de saúde nas práticas de gestão da clínica e de qualificação assistencial em hospitais prestadores de serviços. MÉTODOS: Estudo transversal realizado em inquérito de abrangência nacional, cujo universo foi constituído pelos hospitais prestadores de serviços às operadoras de planos de saúde em 2006. Foi construída uma amostra de 83 unidades, estratificada segundo macrorregião do Brasil e tipo de hospital. ...

  5. First estimate of bootstrap current in the ETE small aspect ratio tokamak

    International Nuclear Information System (INIS)

    A first estimate of the bootstrap current in the ETE (Experimento Tokamak Esferico) small aspect ratio tokamak using the Hirshman single-ion collisionless model shows that we can expect a ratio of 15 to 30% of total bootstrap current in relation to the total equilibrium current depending on the optimization level of the plasma profile parameters. Bootstrap current levels basically depend on the βp values which must be kept under a critical level due to stability conditions and current alignment requirements. Preliminary studies of Shaing's predictions regarding bootstrap current calculations in collisional plasmas are briefly described and different methods for the trapped particle fraction calculation are also illustrated. (Author)

  6. Bayesian Interpretations of Heteroskedastic Consistent Covariance Estimators Using the Informed Bayesian Bootstrap

    OpenAIRE

    Dale Poirier

    2008-01-01

    This paper provides Bayesian rationalizations for White’s heteroskedastic consistent (HC) covariance estimator and various modifications of it. An informed Bayesian bootstrap provides the statistical framework.

  7. Um exame dos modelos de redes de filas abertas aplicados a sistemas de manufatura discretos: parte II A survey on open queueing network models applied to discrete manufacturing systems: part II

    OpenAIRE

    Gabriel R. Bitran; Reinaldo Morabito

    1995-01-01

    Este artigo apresenta a segunda (e última) parte do nosso exame dos modelos de redes de filas abertas aplicados a sistemas de manufatura discretos. Nosso enfoque é em modelos de projeto e planejamento de job-shops. Na primeira parte (BITRAN & MORABITO, 1995b) revisamos métodos de decomposição exatos e aproximados para modelos de avaliação de desempenho em sistemas com múltiplas classes de produtos e diversas estações de trabalho. Nesta segunda parte examinamos modelos de otimização de três ca...

  8. A Bootstrap Approach to an Affordable Exploration Program

    Science.gov (United States)

    Oeftering, Richard C.

    2011-01-01

    This paper examines the potential to build an affordable sustainable exploration program by adopting an approach that requires investing in technologies that can be used to build a space infrastructure from very modest initial capabilities. Human exploration has had a history of flight programs that have high development and operational costs. Since Apollo, human exploration has had very constrained budgets and they are expected be constrained in the future. Due to their high operations costs it becomes necessary to consider retiring established space facilities in order to move on to the next exploration challenge. This practice may save cost in the near term but it does so by sacrificing part of the program s future architecture. Human exploration also has a history of sacrificing fully functional flight hardware to achieve mission objectives. An affordable exploration program cannot be built when it involves billions of dollars of discarded space flight hardware, instead, the program must emphasize preserving its high value space assets and building a suitable permanent infrastructure. Further this infrastructure must reduce operational and logistics cost. The paper examines the importance of achieving a high level of logistics independence by minimizing resource consumption, minimizing the dependency on external logistics, and maximizing the utility of resources available. The approach involves the development and deployment of a core suite of technologies that have minimum initial needs yet are able expand upon initial capability in an incremental bootstrap fashion. The bootstrap approach incrementally creates an infrastructure that grows and becomes self sustaining and eventually begins producing the energy, products and consumable propellants that support human exploration. The bootstrap technologies involve new methods of delivering and manipulating energy and materials. These technologies will exploit the space environment, minimize dependencies, and

  9. Two novel applications of bootstrap currents: snakes and jitter stabilization

    International Nuclear Information System (INIS)

    Both neoclassical theory and certain turbulence theories of particle transport in tokamaks predict the existence of bootstrap (i.e., pressure-driven) currents. Two new applications of this form of non-inductive current are considered in this work. The first is an explanation of the 'snake' phenomenon observed in JET based on steady-state nonlinear tearing theory. The second is an active method of dynamic stabilization of the m=1 mode using the 'jitter' approach suggested by Thyagaraja et al in a recent paper. (author) 11 refs

  10. Characteristics of the bootstrap estimate of discrepant data sets

    International Nuclear Information System (INIS)

    We present in this paper a Bootstrap Method to estimate a best value and its standard deviation for a discrepant set of data. The method is applied to the determination of the half-lives of 137Cs, 90Sr, 252Cf, Tritium, 35S, 55Fe, and 99Mo. The self-consistency of the method and its capability to reject outliers was tested with good results. The application of the method to the determination of covariance matrices was tried, with poor results. (author)

  11. Microcanonical statistics of black holes and bootstrap condition

    OpenAIRE

    Huang, Wung-Hong

    2000-01-01

    The microcanonical statistics of the Schwarzschild black holes as well as the Reissner-Nordstr$\\sf \\ddot{o}$m black holes are analyzed. In both cases we set up the inequalities in the microcanonical density of states. These are then used to show that the most probable configuration in the gases of black holes is that one black hole acquires all of the mass and all of the charge at high energy limit. Thus the black holes obey the statistical bootstrap condition and, in contrast to the other in...

  12. The S-matrix Bootstrap II: Two Dimensional Amplitudes

    CERN Document Server

    Paulos, Miguel F; Toledo, Jonathan; van Rees, Balt C; Vieira, Pedro

    2016-01-01

    We consider constraints on the S-matrix of any gapped, Lorentz invariant quantum field theory in 1 + 1 dimensions due to crossing symmetry and unitarity. In this way we establish rigorous bounds on the cubic couplings of a given theory with a fixed mass spectrum. In special cases we identify interesting integrable theories saturating these bounds. Our analytic bounds match precisely with numerical bounds obtained in a companion paper where we consider massive QFT in an AdS box and study boundary correlators using the technology of the conformal bootstrap.

  13. Bootstrapped Oblivious Transfer and Secure Two-Party Function Computation

    CERN Document Server

    Wang, Ye

    2009-01-01

    We propose an information theoretic framework for the secure two-party function computation (SFC) problem and introduce the notion of SFC capacity. We study and extend string oblivious transfer (OT) to sample-wise OT. We propose an efficient, perfectly private OT protocol utilizing the binary erasure channel or source. We also propose the bootstrap string OT protocol which provides disjoint (weakened) privacy while achieving a multiplicative increase in rate, thus trading off security for rate. Finally, leveraging our OT protocol, we construct a protocol for SFC and establish a general lower bound on SFC capacity of the binary erasure channel and source.

  14. Bootstrap framework : web-suunnittelun työkaluna

    OpenAIRE

    Peltomäki, Veera

    2014-01-01

    Pienen näytön omaavat mobiililaitteet kasvattavat suosiotaan Internetin selaamisessa. Samaan aikaan modernit pelikonsolit ja SmartTV:t yleistyvät kuluttajien keskuudessa, jolloin Internetiä voi selata suuren näyttötarkkuuden omaavilla laitteilla. Responsiivinen web-suunnittelu vastaa nykypäivän vaatimuksiin, jossa käyttäjät odottavat sivustoilta yhdenmukaista käyttökokemusta, päätelaitteesta riippumatta. Tämä opinnäytetyö käsittelee responsiivisen Bootstrap frameworkin valintaa web-suunni...

  15. Convergence rates of empirical block length selectors for block bootstrap

    OpenAIRE

    Nordman, Daniel J.; Lahiri, Soumendra N.

    2014-01-01

    We investigate the accuracy of two general non-parametric methods for estimating optimal block lengths for block bootstraps with time series – the first proposed in the seminal paper of Hall, Horowitz and Jing (Biometrika 82 (1995) 561–574) and the second from Lahiri et al. (Stat. Methodol. 4 (2007) 292–321). The relative performances of these general methods have been unknown and, to provide a comparison, we focus on rates of convergence for these block length selectors for the moving block ...

  16. Comparing groups randomization and bootstrap methods using R

    CERN Document Server

    Zieffler, Andrew S; Long, Jeffrey D

    2011-01-01

    A hands-on guide to using R to carry out key statistical practices in educational and behavioral sciences research Computing has become an essential part of the day-to-day practice of statistical work, broadening the types of questions that can now be addressed by research scientists applying newly derived data analytic techniques. Comparing Groups: Randomization and Bootstrap Methods Using R emphasizes the direct link between scientific research questions and data analysis. Rather than relying on mathematical calculations, this book focus on conceptual explanations and the use of statistica

  17. A survey of bootstrap methods in finite population sampling

    Directory of Open Access Journals (Sweden)

    Zeinab Mashreghi

    2016-03-01

    Full Text Available We review bootstrap methods in the context of survey data where the effect of the sampling design on the variability of estimators has to be taken into account. We present the methods in a unified way by classifying them in three classes: pseudo-population, direct, and survey weights methods. We cover variance estimation and the construction of confidence intervals for stratified simple random sampling as well as some unequal probability sampling designs. We also address the problem of variance estimation in presence of imputation to compensate for item non-response.

  18. Two new data-dependent choices of m when applying the m-out-of-n bootstrap to hypothesis testing

    OpenAIRE

    Allison, James Samuel; Santana, Leonard; Swanepoel, Jan Willem Hendrik

    2011-01-01

    The traditional non-parametric bootstrap (referred to as the n-out-of-n bootstrap) is a widely applicable and powerful tool for statistical inference, but in important situations it can fail. It is well known that by using a bootstrap sample of size m, different from n, the resulting m-out-of-n bootstrap provides a method for rectifying the traditional bootstrap inconsistency. Moreover, recent studies have shown that interesting cases exist where it is better to use the m-out-of-n bootstrap i...

  19. O conhecimento tático produto de métodos de ensino combinados e aplicados em sequências inversas no voleibol Tactical knowledge as a product of the combination of different teaching methods employed in inversesequences in volleyball

    Directory of Open Access Journals (Sweden)

    Cláudio Olivio Vilela Lima

    2012-03-01

    Full Text Available O objetivo desta pesquisa foi investigar as diferenças entre os métodos de ensino situacional e tradicional no desenvolvimento do conhecimento tático declarativo e processual nas sessões de treinamento de voleibol, bem como observar a influência da ordem de aplicação desses métodos no conhecimento tático. A amostra foi composta por 36 estudantes (sexo masculino - faixa etária de 12 a 14 anos, sendo 22 destes inscritos nas equipes escolares de voleibol e 14 não praticantes de voleibol (grupo controle. Um grupo iniciou o processo de ensino-aprendizagem-treinamento pelo método situacional (GST e outro pelo método tradicional (GTS. Ao final de 15 sessões o método foi invertido e realizado o mesmo número de sessões. Para confirmar a execução do método de ensino foi empregada a observação e categorização dos treinos (STEFANELLO, 1999. Para a avaliação do conhecimento processual foi utilizado o teste KORA (MEMMERT, 2002, no parâmetro tático reconhecer espaços. Já no declarativo usou-se o teste de Conhecimento Tático em Situação de Ataque de Rede (PAULA, 2000. Os três grupos no pré-teste demonstram estar inicialmente no mesmo patamar de conhecimento tático declarativo e processual. No GST, ao se aplicar o método situacional (referente às 15 sessões iniciais, não houve diferença significativa no conhecimento tático declarativo, mas houve no processual convergente e divergente. Já no GTS, ao empregar o método tradicional, não se confirmou o desenvolvimento de nenhum dos conhecimentos táticos. Ao efetuar a inversão do método de ensino, no GST (30 sessões na sequência situacional-tradicional foi apurada melhoria significativa de ambos os conhecimentos táticos processuais. Entretanto, o mesmo não ocorreu no GTS na sequência tradicional-situacional. Os resultados indicam que a sequência de treinamentos referentes ao GST proporcionou melhoras relevantes na inteligência e na criatividade tática dos

  20. Current drive and sustain experiments with the bootstrap current in JT-60

    International Nuclear Information System (INIS)

    The current drive and sustain experiments with the neoclassical bootstrap current are performed in the JT-60 tokamak. It is shown that up to 80% of total plasma current is driven by the bootstrap current in extremely high βp regime (βp = 3.2) and the current drive product Ip (bootstrap) n-bareRp up to 4.4 x 1019 MAm-2 has been attained with the bootstrap current. The experimental resistive loop voltages are compared with the calculations using the neoclassical resistivity with and without the bootstrap current and the Spitzer resistivity for a wide range of the plasma current (Ip = 0.5 -2 MA) and the poloidal beta (βp = 0.1 - 3.2). The calculated resistive loop voltage is consistent with the neoclassical prediction including the bootstrap current. Current sustain with the bootstrap current is tested by terminating the Ip feedback control during the high power neutral beam heating. An enhancement of the L/R decay time than those expected from the plasma resistivity with measured Te and Zeff has been confirmed experimentally supporting the large non-inductive current in the plasma and is consistent with the neoclassical prediction. A new technique to calculate the bootstrap current in multi-collisionality regime for finite aspect ratio tokamak has bee developed. The neoclassical bootstrap current is calculated directly through the force balance equations between viscous and friction forces according to the Hirshman-Sigmar theory. The bootstrap current driven by the fast ion component is also included. Ballooning stability of the high βp plasma are analyzed using the current profiles including the bootstrap current. The plasma pressure is close to the ballooning limit in high βp discharges. (author)

  1. Bootstrap current for small aspect ratio TOKAMAK equilibria

    International Nuclear Information System (INIS)

    Full text. We present equilibrium features of the very small ratio tokamak, TBR-2 E, with the aspect ratio of 1.6, which is being designed in Brazil - a joint project with the participation of the University of Sao Paulo, the State University of Campinas, and the National Institute for Space Research. The equilibria have been studied by using the SELENE-J code developed at JAERI, Japan, by Tokuda et al. We have concentrated our study on the determination of the stability limit by using the critical pressure criterion for ballooning stability and Mercier criterion for other MHD modes. The β-limit values were calculated for the case of the non-inductive current and found that its maximum lies at elongation of 1.7. Increasing the triangularity, the β-limit values increase, but the maximum continues to stay at the same value of elongation. We have also studied the effect of the neo-classical transport properties by changing the plasma temperature (or β values). In particular, we have studied the trapped particles and bootstrap current. We have found that at temperatures as low as 600 eV the transport is already in banana regime and that the bootstrap current may account for a significant part of the total plasma current. (author)

  2. Interaction of bootstrap-current-driven magnetic islands

    International Nuclear Information System (INIS)

    The formation and interaction of fluctuating neoclassical pressure gradient driven magnetic islands is examined. The interaction of magnetic islands produces a stochastic region around the separatrices of the islands. This interaction causes the island pressure profile to be broadened, reducing the island bootstrap current and drive for the magnetic island. A model is presented that describes the magnetic topology as a bath of interacting magnetic islands with low to medium poloidal mode number (m congruent 3-30). The islands grow by the bootstrap current effect and damp due to the flattening of the pressure profile near the island separatrix caused by the interaction of the magnetic islands. The effect of this sporadic growth and decay of the islands (''magnetic bubbling'') is not normally addressed in theories of plasma transport due to magnetic fluctuations. The nature of the transport differs from statistical approaches to magnetic turbulence since the radial step size of the plasma transport is now given by the characteristic island width. This model suggests that tokamak experiments have relatively short-lived, coherent, long wavelength magnetic oscillations present in the steep pressure-gradient regions of the plasma. 42 refs

  3. Dejeto líquido bovino em plantio direto: perda de carbono e nitrogênio por escoamento superficial

    OpenAIRE

    Fabiana de Medeiros Silveira; Nerilde Favaretto; Jeferson Dieckow; Volnei Pauletti; Fabiane Machado Vezzani; Eder David Borges da Silva

    2011-01-01

    A utilização de dejetos de animais na produção agrícola é uma alternativa de disposição do resíduo gerado na atividade pecuária, porém se aplicado inadequadamente pode causar problemas ambientais. Nesse sentido, o objetivo geral deste trabalho foi avaliar as concentrações e perdas de C e N por escoamento superficial em quatro doses de dejeto líquido bovino (0, 60, 120, 180 m³ ha-1 ano-1) aplicado em Latossolo franco-argiloarenoso com 13 % de declividade, manejado em plantio direto com soja, a...

  4. Cluster expansion in the truncated bootstrap model and linear graphs theory

    International Nuclear Information System (INIS)

    Using the formalism of linear graphs theory, we obtain the cluster expansion for the grand potential of interacting hadronic systems in the framework of the truncated bootstrap model. We show that the coefficients of the expansion are constructed from two classes of Cayley-tree graphs contributing with opposite sign, related to the two-phase nature of the truncated bootstrap model. (orig.)

  5. Bootstrap current in toroidal systems in the presence of a nonuniform radial electric field

    International Nuclear Information System (INIS)

    The sheared toroidal rotation driven by non-uniform radial electric field can essentially affect on a bootstrap current profile near the edge E-shear layer in the toroidal systems. The high Eγ and pressure gradients would generate the strong peaking off-axis bootstrap current and naturally sustain the hollow current density profile. (author)

  6. EDGEWORTH EXPANSION AND BOOTSTRAP APPROXIMATION FOR THE STUDENTIZED MLE FROM RANDOMLY CENSORED EXPONENTIAL SAMPLES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper,the author studies the asymptotic accuracies of the one-term Edgeworth expansions and the bootstrap approximation for the studentized MLE from randomly censored exponential population.It is shown that the Edgeworth expansions and the bootstrap approximation are asymptotically close to the exact distribution of the studentized MLE with a rate.

  7. MEAN SQUARED ERRORS OF BOOTSTRAP VARIANCE ESTIMATORS FOR U-STATISTICS

    OpenAIRE

    Mizuno, Masayuki; Maesono, Yoshihiko

    2011-01-01

    In this paper, we obtain an asymptotic representation of the bootstrap variance estimator for a class of U-statistics. Using the representation of the estimator, we will obtain a mean squared error of the variance estimator until the order n^. Also we compare the bootstrap and the jackknife variance estimators, theoretically.

  8. A Bootstrap Generalization of Modified Parallel Analysis for IRT Dimensionality Assessment

    Science.gov (United States)

    Finch, Holmes; Monahan, Patrick

    2008-01-01

    This article introduces a bootstrap generalization to the Modified Parallel Analysis (MPA) method of test dimensionality assessment using factor analysis. This methodology, based on the use of Marginal Maximum Likelihood nonlinear factor analysis, provides for the calculation of a test statistic based on a parametric bootstrap using the MPA…

  9. Comparison of Parametric and Nonparametric Bootstrap Methods for Estimating Random Error in Equipercentile Equating

    Science.gov (United States)

    Cui, Zhongmin; Kolen, Michael J.

    2008-01-01

    This article considers two methods of estimating standard errors of equipercentile equating: the parametric bootstrap method and the nonparametric bootstrap method. Using a simulation study, these two methods are compared under three sample sizes (300, 1,000, and 3,000), for two test content areas (the Iowa Tests of Basic Skills Maps and Diagrams…

  10. On the M fewer than N bootstrap approximation to the trimmed mean

    NARCIS (Netherlands)

    Gribkova, N.; Helmers, R.

    2008-01-01

    We show that the M fewer than N (N is the real data sample size, M denotes the size of the bootstrap resample; M=N ! 0, as M ! 1) bootstrap approximation to the distribution of the trimmed mean is consistent without any conditions on the population distribution F, whereas Efron's naive (i.e. M = N)

  11. Bootstrapping to Test for Nonzero Population Correlation Coefficients Using Univariate Sampling

    Science.gov (United States)

    Beasley, William Howard; DeShea, Lise; Toothaker, Larry E.; Mendoza, Jorge L.; Bard, David E.; Rodgers, Joseph Lee

    2007-01-01

    This article proposes 2 new approaches to test a nonzero population correlation ([rho]): the hypothesis-imposed univariate sampling bootstrap (HI) and the observed-imposed univariate sampling bootstrap (OI). The authors simulated correlated populations with various combinations of normal and skewed variates. With [alpha[subscript "set"

  12. Bootstrapping integrated covariance matrix estimators in noisy jump-diffusion models with non-synchronous trading

    DEFF Research Database (Denmark)

    Hounyo, Ulrich

    -studentized statistics, our results justify using the bootstrap to esitmate the covariance matrix of a broad class of covolatility estimators. The bootstrap variance estimator is positive semi-definite by construction, an appealing feature that is not always shared by existing variance estimators of the integrated...

  13. The critical behavior of hadronic matter: Comparison of lattice and bootstrap model calculations

    OpenAIRE

    Turko, L.

    2015-01-01

    Statistical bootstrap model and the related concept of the limiting temperature begun the discussion about phase transitions in the hadronic matter. This was also the origin of the quark-gluon plazma concept. We discuss here to which extend lattice studies of QCD critical behavior at non-zero chemical potential are compatible with the statistical bootstrap model calculations.

  14. Bootstrapping the Small Sample Critical Values of the Rescaled Range Statistic

    OpenAIRE

    Marwan Izzeldin; Anthony Murphy

    2000-01-01

    Finite sample critical values of the rescaled range or R/S statistic may be obtained by bootstrapping. The empirical size and power performance of these critical values is good. Using the post blackened, moving block bootstrap helps to replicate the time dependencies in the original data. The Monte Carlo results show that the asymptotic critical values in Lo (1991) should not be used.

  15. A Primer on Bootstrap Factor Analysis as Applied to Health Studies Research

    Science.gov (United States)

    Lu, Wenhua; Miao, Jingang; McKyer, E. Lisako J.

    2014-01-01

    Objectives: To demonstrate how the bootstrap method could be conducted in exploratory factor analysis (EFA) with a syntax written in SPSS. Methods: The data obtained from the Texas Childhood Obesity Prevention Policy Evaluation project (T-COPPE project) were used for illustration. A 5-step procedure to conduct bootstrap factor analysis (BFA) was…

  16. The Finite Population Bootstrap - From the Maximum Likelihood to the Horvitz-Thompson Approach

    Directory of Open Access Journals (Sweden)

    Andreas Quatember

    2014-06-01

    Full Text Available The finite population bootstrap method is used as a computer-intensive alternative to estimate the sampling distribution of a sample statis-tic. The generation of a so-called “bootstrap population” is the necessarystep between the original sample drawn and the resamples needed to mimicthis distribution. The most important question for researchers to answer ishow to create an adequate bootstrap population, which may serve as a close-to-reality basis for the resampling process. In this paper, a review of someapproaches to answer this fundamental question is presented. Moreover, anapproach based on the idea behind the Horvitz-Thompson estimator allow-ing not only whole units in the bootstrap population but also parts of wholeunits is proposed. In a simulation study, this method is compared with a moreheuristic technique from the bootstrap literature.

  17. A Local Stable Bootstrap for Power Variations of Pure-Jump Semimartingales and Activity Index Estimation

    DEFF Research Database (Denmark)

    Hounyo, Ulrich; Varneskov, Rasmus T.

    We provide a new resampling procedure - the local stable bootstrap - that is able to mimic the dependence properties of realized power variations for pure-jump semimartingales observed at different frequencies. This allows us to propose a bootstrap estimator and inference procedure for the activity...... index of the underlying process, β, as well as a bootstrap test for whether it obeys a jump-diffusion or a pure-jump process, that is, of the null hypothesis H₀: β=2 against the alternative H₁: β<2. We establish first-order asymptotic validity of the resulting bootstrap power variations, activity index...... estimator, and diffusion test for H0. Moreover, the finite sample size and power properties of the proposed diffusion test are compared to those of benchmark tests using Monte Carlo simulations. Unlike existing procedures, our bootstrap test is correctly sized in general settings. Finally, we illustrate use...

  18. Bootstrapping realized volatility and realized beta under a local Gaussianity assumption

    DEFF Research Database (Denmark)

    Hounyo, Ulrich

    The main contribution of this paper is to propose a new bootstrap method for statistics based on high frequency returns. The new method exploits the local Gaussianity and the local constancy of volatility of high frequency returns, two assumptions that can simplify inference in the high frequency...... context, as recently explained by Mykland and Zhang (2009). Our main contributions are as follows. First, we show that the local Gaussian bootstrap is firstorder consistent when used to estimate the distributions of realized volatility and ealized betas. Second, we show that the local Gaussian bootstrap...... matches accurately the first four cumulants of realized volatility, implying that this method provides third-order refinements. This is in contrast with the wild bootstrap of Gonçalves and Meddahi (2009), which is only second-order correct. Third, we show that the local Gaussian bootstrap is able to...

  19. Sistemas de criação para o acará-bandeira (<em>Pterophyllum scalareem>) - DOI: 10.4025/actascianimsci.v30i4.685 Culture systems for freshwater angelfish (<em>Pterophyllum scalareem>) - DOI: 10.4025/actascianimsci.v30i4.685

    OpenAIRE

    Bruno de Lima Preto; Felipe de Azevedo Silva Ribeiro; João Batista Kochenborger Fernandes

    2009-01-01

    Este trabalho objetivou comparar o desempenho produtivo de acarás-bandeira criados em aquários e em hapas em viveiros escavados dentro de estufa plástica em monocultivo e policultivo com camarão-da-amazônia, em duas densidades de estocagem (1,6 e 3,2 peixes 10-1 L). Utilizou-se delineamento inteiramente casualizado, em esquema fatorial 3x2, correspondendo a três sistemas de produção e duas densidades de estocagem, com quatro repetições por tratamento. Anova e teste de Tukey foram aplicados ao...

  20. AVALIAÇÃO DE DESEMPENHO ORGANIZACIONAL: UM ESTUDO APLICADO EM HOSPITAIS FILANTRÓPICOS

    Directory of Open Access Journals (Sweden)

    Julio Araujo Carneiro da Cunha

    2013-08-01

    Full Text Available An evaluation of organizational performance requires studies that encompass the specificities of the object under analysis, which is valid for health organizations. However, this type of organization has little support from Administration techniques and knowledge, thus generating deficiencies in management and control. As a result, the objective of this article is to develop a model for evaluating the specific performance of philanthropic hospitals and to compare the efficiency of those organizations. A theoretical model was created and subsequently validated by specialists. A data envelopment analysis was conducted by means of using the data from 70 hospitals, collected in a field research. The conclusion is that there is no great availability of managerial information in Brazilian hospitals, and elements were pointed out for increasing sample efficiency.

  1. ESQUEMA FLUX-SPLINE APLICADO A PROBLEMAS DIFUSIVOS TRIDIMENSIONAIS EM REGIME PERMANENTE

    Directory of Open Access Journals (Sweden)

    Paulo César Oliveira

    1999-12-01

    Full Text Available RESUMO Este trabalho teve por finalidade apresentar um esquema de discretização mais eficiente que o tradicional esquema de diferenças centrais, denominado Flux-Spline, a fim de simular, numericamente, problemas tridimensionais governados por difusão. A eficiência do esquema proposto foi avaliada por meio da resolução de problemas-teste com solução analítica conhecida. Verificou-se que tal esquema possui características adequadas de precisão e, portanto, uma opção recomendável para a solução de problemas difusivos tridimensionais.

  2. CONCRETE-RUBBER TYRES USED IN BIKE PATH = CONCRETO COM BORRACHA DE PNEUS APLICADO EM CICLOVIA

    OpenAIRE

    José Franklin Moreira; Vanessa Rosa Pereira Fidelis; João Fernando Dias

    2014-01-01

    Automotive tires have indefinite decomposition in nature and represent great concern about the environmental impacts. The tires disposed of improperly can cause many problems to accumulate water and enhance the proliferation of disease vectors. When directed to landfills can cause instability due to massive voids generated between them. In the case of incineration generate particulate matter and toxic gases becoming a health risk. The constituents of tires as, rubber, nylon and steel may cons...

  3. Sustainability indicators for pipeline projects; Indicadores de sustentabilidade aplicados em empreendimentos dutoviarios

    Energy Technology Data Exchange (ETDEWEB)

    Rossin, Carlos H.; Forte, Ana Paula C.; Ferreira, Alexandre R. [PricewaterhouseCoopers (Brazil)

    2005-07-01

    In today's world, large scale projects can no longer be managed through tradition project management tools. The reasons why traditional controls do not work effectively in such projects, is due in large by the complexity of stake holders engagement found in the project's large areas of influence. These stake holders are composed by the communities, the government, the NGOs, and other institutions that are actively present in the project's area of impact and have power to influence the project's embargo. Therefore, it becomes extremely important to manage these impacts to avoid future conflicts with these stake holders. This new concept is a systematic monitoring system that monitors the project's impacts through the use of global indicators (social, economic and environmental) that not only provide a quantitative measure of change in time, but can be further used as a benchmarking tool to compare performance between projects and companies. (author)

  4. Estudos de cultura in vitro em medronheiro (Arbutus unedo L.) aplicados ao seu melhoramento

    OpenAIRE

    Martins, João Filipe da Silva

    2012-01-01

    A espécie Arbutus unedo (Ericaceae) possui porte arbustivo ou arbóreo. O medronheiro é capaz de suportar temperaturas baixas (até -12ºC) e é tolerante à seca. Encontra-se largamente distribuído ao longo da bacia do Mediterrâneo, desde Espanha até à Turquia, algumas zonas do Norte de África e ilhas Mediterrânicas, e ainda na costa Atlântica, incluindo Irlanda e Portugal. O medronheiro tem várias aplicações: estabilização de solos, programas de reflorestação, floricultura e na produção de compo...

  5. Filtros digitais por transformadas de Fourier aplicados em eletroquímica

    OpenAIRE

    Ricardo Nantes Liang; Wagner Diego Gonçalves; Marccus Victor Almeida Martins; Frank Nelson Crespilho

    2013-01-01

    The electrochemical properties of micro and nano-electrodes are widely investigated due to their low faradaic and capacitive currents, leading to a new generation of smart and implantable devices. However, the current signals obtained in low-dimensional devices are strongly influenced by noise sources. In this paper, we show the evaluation of filters based on Fast Fourier Transform (FFT) and their implementation in a graphical user interface (GUI) in MATLAB®. As a case study, we evaluated an ...

  6. Boundary and Interface CFTs from the Conformal Bootstrap

    CERN Document Server

    Gliozzi, F; Meineri, M; Rago, A

    2015-01-01

    We explore some consequences of the crossing symmetry for defect conformal field theories, focusing on codimension one defects like flat boundaries or interfaces. We study surface transitions of the 3d Ising and other O(N) models through numerical solutions to the crossing equations with the method of determinants. In the extraordinary transition, where the low-lying spectrum of the surface operators is known, we use the bootstrap equations to obtain information on the bulk spectrum of the theory. In the ordinary transition the knowledge of the low-lying bulk spectrum allows to calculate the scale dimension of the relevant surface operator, which compares well with known results of two-loop calculations in 3d. Estimates of various OPE coefficients are also obtained. We also analyze in 4-epsilon dimensions the renormalization group interface between the O(N) model and the free theory and check numerically the results in 3d.

  7. Bootstrapping Security Policies for Wearable Apps Using Attributed Structural Graphs

    Science.gov (United States)

    González-Tablas, Ana I.; Tapiador, Juan E.

    2016-01-01

    We address the problem of bootstrapping security and privacy policies for newly-deployed apps in wireless body area networks (WBAN) composed of smartphones, sensors and other wearable devices. We introduce a framework to model such a WBAN as an undirected graph whose vertices correspond to devices, apps and app resources, while edges model structural relationships among them. This graph is then augmented with attributes capturing the features of each entity together with user-defined tags. We then adapt available graph-based similarity metrics to find the closest app to a new one to be deployed, with the aim of reusing, and possibly adapting, its security policy. We illustrate our approach through a detailed smartphone ecosystem case study. Our results suggest that the scheme can provide users with a reasonably good policy that is consistent with the user’s security preferences implicitly captured by policies already in place. PMID:27187385

  8. Bootstrap position analysis for forecasting low flow frequency

    Science.gov (United States)

    Tasker, Gary D.; Dunne, P.

    1997-01-01

    A method of random resampling of residuals from stochastic models is used to generate a large number of 12-month-long traces of natural monthly runoff to be used in a position analysis model for a water-supply storage and delivery system. Position analysis uses the traces to forecast the likelihood of specified outcomes such as reservoir levels falling below a specified level or streamflows falling below statutory passing flows conditioned on the current reservoir levels and streamflows. The advantages of this resampling scheme, called bootstrap position analysis, are that it does not rely on the unverifiable assumption of normality, fewer parameters need to be estimated directly from the data, and accounting for parameter uncertainty is easily done. For a given set of operating rules and water-use requirements for a system, water managers can use such a model as a decision-making tool to evaluate different operating rules. ?? ASCE,.

  9. Higgs critical exponents and conformal bootstrap in four dimensions

    Science.gov (United States)

    Antipin, Oleg; Mølgaard, Esben; Sannino, Francesco

    2015-06-01

    We investigate relevant properties of composite operators emerging in non-supersymmetric, four-dimensional gauge-Yukawa theories with interacting conformal fixed points within a precise framework. The theories investigated in this work are structurally similar to the standard model of particle interactions, but differ by developing perturbative interacting fixed points. We investigate the physical properties of the singlet and the adjoint composite operators quadratic in the Higgs field, and discover, via a direct computation, that the singlet anomalous dimension is substantially larger than the adjoint one. The numerical bootstrap results are, when possible, compared to our precise findings associated to the four dimensional conformal field theoretical results. To accomplish this, it was necessary to calculate explicitly the crossing symmetry relations for the global symmetry group SU( N ) × SU( N ).

  10. Higgs Critical Exponents and Conformal Bootstrap in Four Dimensions

    CERN Document Server

    Antipin, Oleg; Sannino, Francesco

    2014-01-01

    Within a precise framework, we investigate relevant properties of composite operators emerging in nonsupersymmetric, four-dimensional gauge-Yukawa theories with interacting conformal fixed points. The theories investigated in this work are structurally similar to the standard model of particle interactions, but differ from the standard model by developing perturbative interacting fixed points. We investigate the physical properties of the singlet and the adjoint composite operators quadratic in the Higgs field. We show that, in the Veneziano limit, and at the highest known order in perturbation theory, the singlet sector decouples from the other operators. This fact allows us to test the numerical bootstrap constraints against precise four dimensional conformal field theoretical results.

  11. Bootstrap and the physical values of $\\pi N$ resonance parameters

    CERN Document Server

    Semenov-Tian-Shansky, Kirill M; Vereshagin, Vladimir V

    2007-01-01

    This is the 6th paper in the series developing the formalism to manage the effective scattering theory of strong interactions. Relying on the theoretical scheme suggested in our previous publications we concentrate here on the practical aspect and apply our technique to the elastic pion-nucleon scattering amplitude. We test numerically the pion-nucleon spectrum sum rules that follow from the tree level bootstrap constraints. We show how these constraints can be used to estimate the tensor and vector $NN\\rho$ coupling constants. At last, we demonstrate that the tree-level low energy expansion coefficients computed in the framework of our approach show nice agreement with known experimental data. These results allow us to claim that the extended perturbation scheme is quite reasonable from the computational point of view.

  12. The Analytic Bootstrap and AdS Superhorizon Locality

    CERN Document Server

    Fitzpatrick, A Liam; Poland, David; Simmons-Duffin, David

    2012-01-01

    We take an analytic approach to the CFT bootstrap, studying the 4-pt correlators of d > 2 dimensional CFTs in an Eikonal-type limit, where the conformal cross ratios satisfy |u| 2\\Delta_\\phi\\ + 2n for each integer n as l -> infinity. We show how the rate of approach is controlled by the twist and OPE coefficient of the leading twist operator in the \\phi\\ x \\phi\\ OPE, and we discuss SCFTs and the 3d Ising Model as examples. Additionally, we show that the OPE coefficients of other large spin operators appearing in the OPE are bounded as l -> infinity. We interpret these results as a statement about superhorizon locality in AdS for general CFTs.

  13. Bootstrapping Security Policies for Wearable Apps Using Attributed Structural Graphs.

    Science.gov (United States)

    González-Tablas, Ana I; Tapiador, Juan E

    2016-01-01

    We address the problem of bootstrapping security and privacy policies for newly-deployed apps in wireless body area networks (WBAN) composed of smartphones, sensors and other wearable devices. We introduce a framework to model such a WBAN as an undirected graph whose vertices correspond to devices, apps and app resources, while edges model structural relationships among them. This graph is then augmented with attributes capturing the features of each entity together with user-defined tags. We then adapt available graph-based similarity metrics to find the closest app to a new one to be deployed, with the aim of reusing, and possibly adapting, its security policy. We illustrate our approach through a detailed smartphone ecosystem case study. Our results suggest that the scheme can provide users with a reasonably good policy that is consistent with the user's security preferences implicitly captured by policies already in place. PMID:27187385

  14. Bootstrapping Security Policies for Wearable Apps Using Attributed Structural Graphs

    Directory of Open Access Journals (Sweden)

    Ana I. González-Tablas

    2016-05-01

    Full Text Available We address the problem of bootstrapping security and privacy policies for newly-deployed apps in wireless body area networks (WBAN composed of smartphones, sensors and other wearable devices. We introduce a framework to model such a WBAN as an undirected graph whose vertices correspond to devices, apps and app resources, while edges model structural relationships among them. This graph is then augmented with attributes capturing the features of each entity together with user-defined tags. We then adapt available graph-based similarity metrics to find the closest app to a new one to be deployed, with the aim of reusing, and possibly adapting, its security policy. We illustrate our approach through a detailed smartphone ecosystem case study. Our results suggest that the scheme can provide users with a reasonably good policy that is consistent with the user’s security preferences implicitly captured by policies already in place.

  15. Performance of Bootstrap MCEWMA: Study case of Sukuk Musyarakah data

    Science.gov (United States)

    Safiih, L. Muhamad; Hila, Z. Nurul

    2014-07-01

    Sukuk Musyarakah is one of several instruments of Islamic bond investment in Malaysia, where the form of this sukuk is actually based on restructuring the conventional bond to become a Syariah compliant bond. The Syariah compliant is based on prohibition of any influence of usury, benefit or fixed return. Despite of prohibition, daily returns of sukuk are non-fixed return and in statistic, the data of sukuk returns are said to be a time series data which is dependent and autocorrelation distributed. This kind of data is a crucial problem whether in statistical and financing field. Returns of sukuk can be statistically viewed by its volatility, whether it has high volatility that describing the dramatically change of price and categorized it as risky bond or else. However, this crucial problem doesn't get serious attention among researcher compared to conventional bond. In this study, MCEWMA chart in Statistical Process Control (SPC) is mainly used to monitor autocorrelated data and its application on daily returns of securities investment data has gained widespread attention among statistician. However, this chart has always been influence by inaccurate estimation, whether on base model or its limit, due to produce large error and high of probability of signalling out-of-control process for false alarm study. To overcome this problem, a bootstrap approach used in this study, by hybridise it on MCEWMA base model to construct a new chart, i.e. Bootstrap MCEWMA (BMCEWMA) chart. The hybrid model, BMCEWMA, will be applied to daily returns of sukuk Musyarakah for Rantau Abang Capital Bhd. The performance of BMCEWMA base model showed that its more effective compare to real model, MCEWMA based on smaller error estimation, shorter the confidence interval and smaller false alarm. In other word, hybrid chart reduce the variability which shown by smaller error and false alarm. It concludes that the application of BMCEWMA is better than MCEWMA.

  16. Redução química e biológica do cromo hexavalente aplicado ao solo

    Directory of Open Access Journals (Sweden)

    D. D. Castilhos

    2001-06-01

    Full Text Available Realizou-se um experimento em laboratório, com o objetivo de avaliar não só a redução do cromo hexavalente aplicado ao solo com ênfase ao efeito da aplicação de carbono orgânico, manganês divalente, mas também a participação da microbiota do solo. Utilizaram-se, como unidades experimentais, amostras de 50 g de um Argissolo, acondicionadas em sacos de polipropileno e incubadas durante 42 dias com calcário para elevar o pH a 6,0 (2,0 t ha-1 de CaCO3 + MgCO3 na proporção de 2:1, Cr6+, esterco bovino e Mn2+ nas doses de 20, 50 e 40 mg kg-1, respectivamente. Metade das amostras foi sujeita à esterilização por autoclavagem com o objetivo de eliminar a atividade biológica. A aplicação de esterco bovino e sulfato de manganês promoveu a total redução do cromo hexavalente para cromo trivalente (Cr6+ → Cr3+ no solo, em 42 dias. Os modelos, quadrático e exponencial, foram os que melhor descreveram a cinética de redução com o tempo. A redução do Cr6+ foi estimulada pela atividade microbiana, sendo 16% maior em amostras de solo não esterilizadas, que continham esterco bovino, em comparação com as mesmas amostras esterilizadas por autoclavagem. Os resultados demonstraram que a descontaminação do solo que contém teores tóxicos de Cr6+ pode ser viabilizada tanto pela incorporação de adubo orgânico como pela manutenção de sua atividade biológica.

  17. JuliBootS: a hands-on guide to the conformal bootstrap

    CERN Document Server

    Paulos, Miguel F

    2014-01-01

    We introduce {\\tt JuliBootS}, a package for numerical conformal bootstrap computations coded in {\\tt Julia}. The centre-piece of {\\tt JuliBootS} is an implementation of Dantzig's simplex method capable of handling arbitrary precision linear programming problems with continuous search spaces. Current supported features include conformal dimension bounds, OPE bounds, and bootstrap with or without global symmetries. The code is trivially parallelizable on one or multiple machines. We exemplify usage extensively with several real-world applications. In passing we give a pedagogical introduction to the numerical bootstrap methods.

  18. Ion-Banana-Orbit-Width Effect on Bootstrap Current for Small Magnetic Islands

    International Nuclear Information System (INIS)

    A simple and direct theoretical method has been proposed to investigate the so-called ion-banana-orbit-width (IBW) effect on the bootstrap current in the region of magnetic islands generated by the neoclassical tearing mode (NTM). The result shows that, when the IBW approaches the island width, the (ion) bootstrap current can be partly restored inside the island while the pressure profile is flattened. This can lead to the reduction of the bootstrap current drive on the NTM. The strength of the IBW effect on the NTM is related to the safety factor and the inverse aspect ratio on the rational surface

  19. Bootstrap current in low aspect ratio tokamaks using Maschke equilibrium model

    International Nuclear Information System (INIS)

    A study of relevant aspects of equilibrium and bootstrap current in low-aspect-ratio tokamaks is made using the Maschke equilibrium model, which provides analytic and exact solution of the Grad-Shafranov equation. The current profile in the Maschke model is parabolic, which is a good approximation for actual experimentally observed ones. The results are compared with the Soloviev equilibrium model, that has the current profile almost flat. It is shown that the bootstrap current depends on the geometrical parameter of the plasma column, that is, elongation. The bootstrap current increases with the inverse aspect ratio for elongated cross-section of the plasma column. (author). 6 refs., 2 figs

  20. Bootstrap Sequential Determination of the Co-integration Rank in VAR Models

    DEFF Research Database (Denmark)

    Guiseppe, Cavaliere; Rahbæk, Anders; Taylor, A.M. Robert

    empirical rejection frequencies often very much in excess of the nominal level. As a consequence, bootstrap versions of these tests have been developed. To be useful, however, sequential procedures for determining the co-integrating rank based on these bootstrap tests need to be consistent, in the sense...... we fill this gap in the literature by proposing a bootstrap sequential algorithm which we demonstrate delivers consistent cointegration rank estimation for general I(1) processes. Finite sample Monte Carlo simulations show the proposed procedure performs well in practice....

  1. Bootstrap confidence intervals in a complex situation: A sequential paired clinical trial

    International Nuclear Information System (INIS)

    This paper considers the problem of determining a confidence interval for the difference between two treatments in a simplified sequential paired clinical trial, which is analogous to setting an interval for the drift of a random walk subject to a parabolic stopping boundary. Three bootstrap methods of construction are applied: Efron's accelerated bias-covered, the DiCiccio-Romano, and the bootstrap-t. The results are compared with a theoretical approximate interval due to Siegmund. Difficulties inherent in the use of these bootstrap methods in a complex situations are illustrated. The DiCiccio-Romano method is shown to be the easiest to apply and to work well. 13 refs

  2. Sistema HACCP aplicado à indústria transformadora de carnes

    OpenAIRE

    Pinheiro, Sandra Cristina da Silva

    2009-01-01

    O trabalho aqui apresentado consiste na aplicação do sistema de HACCP (Hazard Analysis and Critical Points) ou APPCC (Análise dos Perigos e Pontos Críticos de Controlo) à Indústria do Sector Alimentar, em particular à Indústria Transformadora de Carnes. O HACCP é uma ferramenta preventiva de organização que garante a Segurança Alimentar. Permite identificar riscos alimentares específicos ligados a um alimento, a uma bebida ou até ao processo de fabrico, e ajuda a adoptar os mei...

  3. Reajustando o limite de tolerância biológica aplicado à plumbemia no Brasil

    Directory of Open Access Journals (Sweden)

    Ricardo Cordeiro

    1996-12-01

    Full Text Available Foram alocados aleatoriamente vinte trabalhadores expostos ocupacionalmente ao chumbo em uma indústria de acumuladores elétricos de médio porte, no interior do Estado de São Paulo, os quais apresentavam plumbemia e excreção urinária do ácido delta-aminolevulínico, nos últimos dois anos, sempre menores que 60 µg/dL e 10 mg/L, respectivamente. Os trabalhadores foram submetidos a eletroneurografia do nervo radial direito e a dosagem de plumbemia. Com estas medidas ajustou-se um modelo de regressão linear simples de primeira ordem, tendo como variável dependente a velocidade de condução e como variável independente a plumbemia. Analisando-se a regressão ajustada, infere-se que o valor preditivo negativo do limite de tolerância biológica brasileiro aplicado à plumbemia seja de apenas 0,63. O estudo sugere que o valor do referido limite de tolerância deva ser reduzido do atual valor de 60 µg/dL para 32 µg/dL, para ter um valor preditivo negativo de 0,99.

  4. Calculation of the bootstrap current profile for the TJ-II stellarator

    International Nuclear Information System (INIS)

    Calculations of the bootstrap current for the TJ-II stellarator are presented. DKES and NEO-MC codes are employed; the latter has allowed, for the first time, the precise computation of the bootstrap transport coefficient in the long-mean-free-path regime of this device. The low error bars allow a precise convolution of the monoenergetic coefficients, which is confirmed by error analysis. The radial profile of the bootstrap current is presented for the first time for the 1004464 configuration of TJ-II for three different collisionality regimes. The bootstrap coefficient is then compared with that of other configurations of TJ-II regularly operated. The results show qualitative agreement with toroidal current measurements; precise comparison with real discharges is ongoing.

  5. Extended estimations of neoclassical transport for the TJ-II stellarator: The bootstrap current

    International Nuclear Information System (INIS)

    This work extends previous Monte Carlo estimations of neoclassical transport for the TJ-II stellarator [V. Tribaldos, Phys. Plasmas 8, 1229 (2001)] to include, for the first time, the bootstrap current in low collisionality electron cyclotron resonance heated (ECRH) plasmas. The calculations are based on the mono-energetic coefficients calculated with DKES [W. I. van Rij and S. P. Hirshman, Phys. Fluids B 1, 563 (1989)] and MOCA codes. It is shown that despite the difficulties of calculating these coefficient in the long mean free path for TJ-II configurations, the bootstrap current can be accurately estimated based on the moderate temperatures measured in this device with and without enforcing momentum conservation [H. Maassberg et al., Phys. Plasmas 16, 072504 (2009)]. The computed bootstrap current is found to be in fair agreement with the currents being measured in ECRH regimes. Finally, the effect of the bootstrap current on the rotational transform profile is discussed.

  6. Bootstrap-based confidence estimation in PCA and multivariate statistical process control

    DEFF Research Database (Denmark)

    Babamoradi, Hamid

    on assumptions that do not always hold in practice. The aim of this thesis was to illustrate the concept of bootstrap-based confidence estimation in PCA and MSPC. It particularly shows how to build bootstrapbased confidence limits in these areas to be used as alternative to the traditional....../asymptotic limits. The goal was to improve process monitoring by improving the quality of MSPC charts and contribution plots. Bootstrapping algorithm to build confidence limits was illustrated in a case study format (Paper I). The main steps in the algorithm were discussed where a set of sensible choices (plus the...... recommended decisions) to build rational confidence limits were given. Two NIR datasets were used to study the effect of outliers and bimodal distributions on the bootstrap-based limits. The results showed that bootstrapping can give reasonable estimate of distributions for scores and loadings. It can also be...

  7. Bootstrap Prediction Intervals in Non-Parametric Regression with Applications to Anomaly Detection

    Science.gov (United States)

    Kumar, Sricharan; Srivistava, Ashok N.

    2012-01-01

    Prediction intervals provide a measure of the probable interval in which the outputs of a regression model can be expected to occur. Subsequently, these prediction intervals can be used to determine if the observed output is anomalous or not, conditioned on the input. In this paper, a procedure for determining prediction intervals for outputs of nonparametric regression models using bootstrap methods is proposed. Bootstrap methods allow for a non-parametric approach to computing prediction intervals with no specific assumptions about the sampling distribution of the noise or the data. The asymptotic fidelity of the proposed prediction intervals is theoretically proved. Subsequently, the validity of the bootstrap based prediction intervals is illustrated via simulations. Finally, the bootstrap prediction intervals are applied to the problem of anomaly detection on aviation data.

  8. Web-sivujen kehitys ja mobiilioptimointi käytettäessä Bootstrap-alustaa

    OpenAIRE

    Myhrberg, Mikael

    2015-01-01

    Opinnäytetyön aihe perustuu omakohtaiseen kokemukseen web-kehityksestä. Taustana toimi myös aiemmin hyvinkääläiselle yritykselle tehty Bootstrap-projekti. Tarkoituksena oli esitellä Bootstrap-koodikirjastoa ja sitä, kuinka sitä voi käyttää alustana käytännön web-kehityksessä ja mobiilioptimoinnissa. Tavoitteena oli saada lukija ymmärtämään, mikä Bootstrap on ja mitä web-sivujen mobiilioptimointi tarkoittaa. Lisäksi tarkoituksena oli käytännön esimerkkiprojektin avulla näyttää, miten Bootstrap...

  9. Optimal condition for oscillating field current drive in a bootstrapped tokamak

    International Nuclear Information System (INIS)

    A simple physical form of the optimal condition for oscillating field current drive (OFCD) in a bootstrapped tokamak is given. The results of the analysis suggest that the required OFCD driving frequency can be reduced in a bootstrapped tokamak directly in proportion to the reduction in the OFCD fraction of the total toroidal current, while the total required poloidal magnetic flux content is independent of the OFCD driving frequency. (author)

  10. Sensitivity Analysis to Efficiency Scores : How to Bootstrap in Nonparametric Frontier Models

    OpenAIRE

    Simar, Léopold; Wilson, Paul

    1995-01-01

    Efficiency scores of production units are generally measured relative to an estimated production frontier. Nonparametric estimators (DEA, FDH, ... ) are based on a finite sample of observed production units. The bootstrap is one easy way to analyze the sensitivity of efficiency scores relative to the sampling variations of the estimated frontier. The main point in order to validate the bootstrap is to define a reasonable data generating process in this complex framework and to propose a reaso...

  11. Bootstrap methods for lasso-type estimators under a moving-parameter framework

    OpenAIRE

    Cai, W; Lee, SMS

    2012-01-01

    We study the distributions of Lasso-type regression estimators in a moving-parameter asymptotic framework, and consider various bootstrap methods for estimating them accordingly. We show, in particular, that the distribution functions of Lasso-type estimators, including even those possessing the oracle properties such as the adaptive Lasso and the SCAD, cannot be consistently estimated by the bootstraps uniformly over the space of the regression parameters, especially when some of the regre...

  12. Desenvolupament de tema per a WordPress basat en el framework Twitter Bootstrap

    OpenAIRE

    Roca Escoda, Víctor

    2014-01-01

    Desenvolupament de tema per a WordPress fet a mida per a una web d'empresa, utilitzant el marc de treball Twitter Bootstrap que permet adaptar la pàgina a l'entorn de l'usuari. Desarrollo de tema para WordPress hecho a medida para una web de empresa, utilizando el marco de trabajo Twitter Bootstrap que permite adaptar la página al entorno del usuario. Bachelor thesis for the Multimedia program.

  13. Approximate regenerative-block bootstrap for Markov chains: some simulation studies

    OpenAIRE

    Bertail, Patrice; Clémençon, Stéphan

    2007-01-01

    Abstract : In Bertail & Clémençon (2005a) a novel methodology for bootstrappinggeneral Harris Markov chains has been proposed, which crucially exploits their renewalproperties (when eventually extended via the Nummelin splitting technique) and has theoreticalproperties that surpass other existing methods within the Markovian framework(bmoving block bootstrap, sieve bootstrap etc...). This paper is devoted to discuss practicalissues related to the implementation of this specific resampling met...

  14. Fixed-b Subsampling and Block Bootstrap: Improved Confidence Sets Based on P-value Calibration

    OpenAIRE

    Shao, Xiaofeng; Politis, Dimitris N.

    2012-01-01

    Subsampling and block-based bootstrap methods have been used in a wide range of inference problems for time series. To accommodate the dependence, these resampling methods involve a bandwidth parameter, such as subsampling window width and block size in the block-based bootstrap. In empirical work, using different bandwidth parameters could lead to different inference results, but the traditional first order asymptotic theory does not capture the choice of the bandwidth. In this article, we p...

  15. Sensitivity Analysis of Efficiency Scores: How to Bootstrap in Nonparametric Frontier Models

    OpenAIRE

    Simar, Léopold; Paul W. Wilson

    1998-01-01

    Efficiency scores of production units are generally measured relative to an estimated production frontier. Nonparametric estimators (DEA, FDH, \\cdots ) are based on a finite sample of observed production units. The bootstrap is one easy way to analyze the sensitivity of efficiency scores relative to the sampling variations of the estimated frontier. The main point in order to validate the bootstrap is to define a reasonable data-generating process in this complex framework and to propose a re...

  16. Ajuste recursivo con transformaciones invariantes y bootstrapping: El caso de una caminata aleatoria con intercepto

    OpenAIRE

    Eddy Lizarazu Alanez; Jose A. Villasenor Alva

    2010-01-01

    Usamos simulaciones de Monte Carlo para estudiar el desempeno de la prueba de raiz unitaria de Shin-So (DFSS) bajo los enfoques de transformaciones invariantes y el bootstrapping. Si la hipotesis alternativa es un proceso estacionario alrededor de una tendencia lineal, entonces la prueba bootstrap parametrica es la mejor en terminos de la potencia estadistica. Sin embargo, si transformamos las observaciones para construir una prueba invariante, entonces la prueba DFSS es la mejor. Por consigu...

  17. A two-stage productivity analysis using bootstrapped Malmquist index and quantile regression

    OpenAIRE

    Kaditi, Eleni A.; Nitsi, Elisavet I.

    2009-01-01

    This paper examines the effects of farm characteristics and government policies in enhancing productivity growth for a sample of Greek farms, using a two-stage procedure. In the 1st-stage, non-parametric estimates of Malmquist index and its decompositions are computed, while a bootstrapping procedure is applied to provide their statistical precision. In the 2nd-stage, the productivity growth estimates are regressed on various covariates using a bootstrapped quantile regression approach. The e...

  18. A Comparison of Correlation Coefficients via a Three-Step Bootstrap Approach

    OpenAIRE

    2010-01-01

    In this article we compare ten correlation coefficients using a three-step bootstrap approach (TSB). A three-step bootstrap is applied to determine the optimal repetitions, $B$, to estimate the standard error of the statistic with certain degree of accuracy. The coefficients in question are Pearson product moment ($r$), Spearman's rho ($\\rho$), Kendall's tau ($\\tau$) , Spearman's Footrule ($F_t$), Symmetric Footrule ($C$), the Greatest deviation ($R_g$), the Top - Down ($r_T$), Weighted Ken...

  19. Effect of Bias Estimation on Coverage Accuracy of Bootstrap Confidence Intervals for a Probability Density

    OpenAIRE

    Hall, Peter

    1992-01-01

    The bootstrap is a poor estimator of bias in problems of curve estimation, and so bias must be corrected by other means when the bootstrap is used to construct confidence intervals for a probability density. Bias may either be estimated explicitly, or allowed for by undersmoothing the curve estimator. Which of these two approaches is to be preferred? In the present paper we address this question from the viewpoint of coverage accuracy, assuming a given number of derivatives of the unknown den...

  20. Bootstrapping Structural VARs: Avoiding a Potential Bias in Confidence Intervals for Impulse Response Functions

    OpenAIRE

    Phillips, Kerk L.; David E. Spencer

    2010-01-01

    Constructing bootstrap confidence intervals for impulse response functions (IRFs) from structural vector autoregression (SVAR) models has become standard practice in empirical macroeconomic research. The accuracy of such confidence intervals can deteriorate severely, however, if the bootstrap IRFs are biased. We document an apparently common source of bias in the estimation of the VAR error covariance matrix which can be easily reduced by a scale adjustment. This bias is generally unrecogn...