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  1. Caída de la flor en kiwi causada por bacterias fitopatógenas

    OpenAIRE

    González, A.J.

    2010-01-01

    La cáida de flor en kiwi causa pérdidas importantes de producción cuando las condiciones climatológicas son favorables al desarrollo de las bacterias. En Asturias se han descrito dos especies bacterianas, "Pseudomonas viridiflava" y "P. syringae", como agentes causales de este problema

  2. A arte de ser Beija-Flor na tripla jornada de trabalho da mulher

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    Adriane Vieira

    2013-06-01

    Full Text Available Com presença expressiva no mercado de trabalho, as mulheres vêm ampliando continuamente sua participação nos mais diversos cargos e funções, no entanto continuam sendo as principais responsáveis pelas atividades do lar e pelo cuidado dos filhos. A situação agrava-se com a crescente demanda por qualificação, exigindo que essas trabalhadoras cumpram, muitas vezes, três jornadas de trabalho: profissional, familiar e educacional. Este estudo teve como objetivo analisar os mecanismos de dominação refletidos nas ações de mulheres que "conciliam" as atividades profissionais, o cuidado com a família e as exigências da educação continuada, utilizando como referência principal o trabalho de Pierre Bourdieu. Trata-se de uma pesquisa qualitativa, cuja coleta de dados ocorreu através de entrevista, buscando obter as histórias orais temáticas de cinco mulheres. Os relatos foram submetidos à técnica de análise do conteúdo e os resultados revelam que a busca pela qualificação deriva da preocupação com a empregabilidade e que a disputa profissional está ligada não apenas ao gênero, mas também à concorrência com profissionais mais jovens. Apesar de as mulheres fazerem referência ao início de uma revisão da divisão sexual de tarefas do lar, a empregada doméstica ainda se revela fundamental nesse processo de delegação e de conciliação. Para se dedicar aos estudos, elas abdicaram do lazer, não como um sacrifício, mas sim como um ato de nova significação das coisas. Tal qual beija-flor, que conjuga trabalho e reprodução das espécies botânicas, elas esperam conciliar as jornadas com rapidez, mas também com graça e leveza.

  3. Levantamento florístico da floresta serrana da reserva biológica de Serra Negra, microrregião de Itaparica, Pernambuco, Brasil

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    Rodal Maria Jesus Nogueira

    2002-01-01

    Full Text Available O levantamento florístico, de duas áreas da Reserva Biológica de Serra Negra, localizada entre os municípios de Inajá e Floresta (8º35' - 8º38' S e 38º02' - 38º04' W, foi realizado fazendo-se 19 excursões para coleta de material botânico de Bryophyta, Pteridophyta e Magnoliophyta. No total foram coletados 319 taxa, 255 na floresta densa, situada no topo, e 117 na floresta aberta, localizada na escarpa meridional, com 12,5 % de similaridade (Jaccard. A análise de agrupamento mostrou que as duas áreas têm maiores similaridades com outras florestas serranas da região nordeste. A presença de condições abióticas diferenciadas, úmida no topo e mais seca na escarpa meridional, justifica as diferenças florísticas. Na floresta densa ocorreu um grande número de espécies com ampla distribuição nos domínios amazônico e atlântico, enquanto na floresta aberta parte das espécies foi mais relacionada à vegetação caducifólia espinhosa (caatinga, e outras têm distribuição ampla em florestas neotropicais.

  4. Anatomia e desenvolvimento ontogenético da flor de mandioca Anatomy and development of the manioc flower

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    Antonieta Pia de Toledo

    1963-01-01

    Full Text Available É discutida a anatomia vascular da flor de mandioca (Manihot utilissima Pohl. O pedúnculo apresenta um cilindro contínuo de tecido vascular, do qual partem os traços das sépalas em número de dez. Cinco dêles ramificam-se alternadamente e vão constituir os feixes laterais de sépalas adjacentes. Os estames possuem um único traço vascular e cada carpelo tem três traços. Anatômicamente o ovário mostra-se formado por: uma epiderme externa, com estômatos; o parênquima. onde se ramificam os feixes vasculares, e a epiderme interna. A antera apresenta quatro sacos polínicos. No estado de maturação dos grãos de polem, cada saco polínico é envolvido por uma epiderme unisseriada e pelo endotécio.Flower development of the manioc (Manihot utilissima Pohl is acropetal. The early phases of cellular differentiation of the floral appendages are similar. All organs develop by anticlinal divisions of the surface layer, accompanied by periclinal divisions in the second tunica layer, and also in the outermost layer of the corpus, followed by the formation of an apical meristem. The carpels and sepals also originate from marginal initials. The vascular anatomy is described. The pedicel has a complete vascular cylinder from which ten bundles branch out to constitute the sepal traces. Five of these bundles bifurcate alternately to form the lateral bundles of adjacent sepals. The stamen has one single trace and each carpel has three traces. Anatomically the ovary is formed by an outer epidermis provided with stomata, a medium parenchymatous layer in which the vascular bundles develop, an inner epidermis. At maturity each anther exhibits four pollen sacs surrounded bv a uniseriate epidermis and a specialized endothecium with secondary thickness.

  5. FLOR como Património Natural e Cultural: Projeto Ecológico de Educação Artística na Ilha da Madeira, das Instituições Sociais à Comunidade

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    Cláudia Sofia Dias Sousa

    2013-09-01

    Full Text Available O presente artigo apresenta uma reflexão contendo as principais ideias sobre um projeto de Educação Artística com o tema “FLOR como Património Natural e Cultural” realizado na ilha da Madeira. O Projeto FLOR foi concebido no âmbito do Mestrado em Educação Artística da Faculdade de Belas Artes de Lisboa, desenvolvendo-se em duas fases: a contextualização e o fazer artístico, nas instituições sociais; e a abertura à comunidade através da participação na exposição ECO FLOR. Esta abertura permitiu a observação e fruição de diversas exposições e actividades de cariz artístico e cultural, nomeadamente CORAÇÃO VERDE e Exposição da Flor, inseridas no certame da Festa da Flor, que reflectiram diferentes perspetivas em torno dos temas: Flor e Jardim. O projeto foi desenvolvido com juniores e seniores, com o intuito de explorar questões ambientais diversas: preservação, património, ecologia e sustentabilidade. Os resultados reflectem a visão dos participantes sobre a sua ilha jardim, manifestada pela expressão artística em que se relacionaram a Educação, a Natureza e a Arte.

  6. Turismo e eventos culturais: a Festa da Flor na Ilha da Madeira e as motivações dos turistas

    OpenAIRE

    Marujo, Noémi

    2014-01-01

    Os eventos culturais desempenham um papel essencial no contexto social, cultural, político e económico de um país ou de uma região. No turismo, eles surgem como uma ‘arma’ para identificar ou posicionar um destino, captar mais turistas, melhorar a imagem do lugar ou combater a sazonalidade. As motivações para participar num evento cultural são múltiplas e dependem da natureza do evento. O presente artigo pretende identificar e analisar as duas principais motivações dos turistas para visitarem...

  7. Levantamento florístico da Área de Proteção Ambiental de Jericoacoara, Ceará

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    Matias Lígia Queiroz

    2001-01-01

    Full Text Available Estudou-se a composição florística da Área de Proteção Ambiental de Jericoacoara, Estado do Ceará, nordeste do Brasil (2°47' - 2°51'S e 40°36' - 40°24'W. O clima da região é do tipo Aw` (segundo a classificacação de Köppen com temperaturas médias oscilando entre 35°C e 22°C, com chuvas de verão (dezembro a junho, possuindo um período de estiagem de 5 a 6 meses, frequentemente interrompido por chuvas ocasionais em setembro e outubro, e apresenta índice xerotérmico de Gaussen variável entre 100 e 150. As formações vegetacionais estudadas foram: vegetação com influência flúvio-marinha ou manguezal em estuários e na região de pós-praia e vegetação com influência marinha ("restingas". Foram identificadas 87 espécies, 77 gêneros e 39 famílias. As famílias que apresentaram maior riqueza específica foram: Poaceae (13%, Cyperaceae (13%, Fabaceae (6%, Amaranthaceae (6% e Rubiaceae (6%. Alguns aspectos relacionados a conservação ambiental na APA são discutidos.

  8. Variações estruturais e florísticas do carrasco no planalto da Ibiapaba, estado do Ceará

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    ARAÚJO F. S. de

    1999-01-01

    Full Text Available Carrasco é uma vegetação xerófila arbustiva densa alta, ainda pouco conhecida, que ocorre no domínio semi-árido do nordeste do Brasil, sobre Areias Quartzosas distróficas profundas, entre 700 e 900 m de altitude, no planalto da Ibiapaba e chapada do Araripe. Este trabalho tem por objetivo conhecer a estrutura e a composição da comunidade lenhosa e possíveis relações dessas variações espaciais com variáveis pedológicas. Em Jaburuna (3°54'34"S, 40°59'24"W, cerca de 830 m de altitude, município de Ubajara, no norte do planalto da Ibiapaba, foram alocadas 100 parcelas de 10 x 10 m, por sorteio de pares de números em um sistema de coordenadas. Foram medidos o perímetro do caule no nível do solo e a altura vertical do sistema aéreo de todos os indivíduos lenhosos com diâmetro mínimo de 3 cm, exceto as alturas das trepadeiras. No centro de cada parcela foi retirada uma alíquota de solo entre 0 e 50 cm de profundidade. Levantamentos publicados do carrasco no sul da Ibiapaba foram usados para comparação. Ocorreu forte concentração de dominância e as espécies Acacia langsdorffii, Piptadenia moniliformis e Thiloa glaucocarpa alternaram-se em abundância nos diferentes levantamentos. Em Jaburuna, 81% das plantas amostradas foram representadas por arbustos, 14% por árvores (a maioria com diâmetro do caule < 10 cm e altura < 6 m e 5% por trepadeiras. Foram calculados a distância Camberra e o índice de Jaccard a partir de uma matriz primária contendo 87 espécies (com 5 ou mais indivíduos e 175 parcelas (incluindo dados publicados para o sul da Ibiapaba. As análises de agrupamentos mostraram que o carrasco apresenta grande variação florística no espaço. Foi construída uma matriz com as variáveis físicas e químicas do solo por parcela e feita a análise da correspondência canônica entre a matriz primária e a matriz de solo. Ocorreu associação de espécies com as variáveis edáficas tais como: menor pH e

  9. Causality

    Science.gov (United States)

    Pearl, Judea

    2000-03-01

    Written by one of the pre-eminent researchers in the field, this book provides a comprehensive exposition of modern analysis of causation. It shows how causality has grown from a nebulous concept into a mathematical theory with significant applications in the fields of statistics, artificial intelligence, philosophy, cognitive science, and the health and social sciences. Pearl presents a unified account of the probabilistic, manipulative, counterfactual and structural approaches to causation, and devises simple mathematical tools for analyzing the relationships between causal connections, statistical associations, actions and observations. The book will open the way for including causal analysis in the standard curriculum of statistics, artifical intelligence, business, epidemiology, social science and economics. Students in these areas will find natural models, simple identification procedures, and precise mathematical definitions of causal concepts that traditional texts have tended to evade or make unduly complicated. This book will be of interest to professionals and students in a wide variety of fields. Anyone who wishes to elucidate meaningful relationships from data, predict effects of actions and policies, assess explanations of reported events, or form theories of causal understanding and causal speech will find this book stimulating and invaluable.

  10. Produtividade e qualidade da flor-de-seda em diferentes densidades e sistemas de plantio Productivity and quality of rooster tree in different planting densities and planting systems

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    Maria Verônica Meira de Andrade

    2008-01-01

    Full Text Available Avaliou-se o efeito de dois sistemas de plantio (sem camalhão e com camalhão e de três espaçamentos (1,0 × 1,5 m; 1,5 × 2,0 m; e 2,0 × 2,0 m sobre a qualidade e a produtividade de flor-de-seda aos 60 dias de rebrotação. Utilizou-se o delineamento experimental com blocos casualizados em esquema fatorial 2 × 3 (dois sistemas de manejo do solo e três densidades de plantio com cinco repetições, em parcelas subdivididas no espaço e no tempo. Plantas escolhidas aleatoriamente foram cortadas, separadas por tratamento e analisadas quanto aos teores de matéria seca (MS, matéria orgânica (MO, cinzas, extrato etéreo (EE, proteína bruta (PB, fibra em detergente neutro (FDN, fibra em detergente ácido (FDA, celulose, hemicelulose, lignina, carboidratos não-fibrosos (CNF e carboidratos totais (CT e quanto à produtividade (kg MS/ha. Os sistemas de manejo do solo e as densidades de plantio não influenciaram a composição em MO, cinzas, FDN, EE, lignina, celulose, CNF e CT. As densidades de plantio influenciaram o teor de hemicelulose e FDA. O sistema de manejo do solo com camalhão teve efeito linear decrescente sobre o teor de PB. A maior produtividade de MS (699,72 kg/ha da flor-de-seda foi verificada no sistema de plantio mais adensado (1,0 m × 1,5 m e correspondeu a 6.666 plantas/ha.The effect of two soil handling systems was evaluated (without furrow and with furrow, three spacing (1.0 m × 1.5 m; 1.5 m × 2.0 m and 2.0 m × 2.0 m on the quality and the productivity of rooster tree 60 days after cut. It was used a split-plot (space and time factorial arrangement in a randomized block design. Factors were two soil handling systems and three planting densities (2 × 3 with five replications per treatment. Plants chosen randomly were cut, separated in accordance with treatments and analyed the contents of dry matter (DM, organic matter (OM, mineral matter (MM, ether extract (EE, crude protein (CP, neutral detergent fiber (NDF, acid

  11. Aspectos florísticos da vegetação de restinga no litoral de Pernambuco Floristics aspects of restinga vegetation in the coast of Pernambuco - Brazil

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    Ana Cláudia Sacramento

    2007-12-01

    Full Text Available As zonas costeiras acolhem quadros de alta riqueza e relevância ecológica que as qualificam como importante ecossistema para conservação. O objetivo deste estudo foi listar as espécies que compõem a restinga da praia do Paiva e descrever a sua fisionomia. A área de restinga compreende 147 ha, situa-se no Município do Cabo de Santo Agostinho, PE, sob as coordenadas 08º07'30"S e 35º00'55"W. As coletas florísticas foram realizadas durante 28 meses, em todos os estratos. O solo foi classificado como Neossolo Quartzarênico; foram determinadas duas fisionomias: a floresta não-inundável e o fruticeto aberto não-inundável. Foram listadas 124 espécies, distribuídas em 103 gêneros e 55 famílias. As famílias com maior número de espécies foram Myrtaceae, com 11 espécies, Cyperaceae (10, Fabaceae (8, Euphorbiaceae (7, Rubiaceae (6 e Asteraceae (5. As espécies Anacardium occidentale, Tapirira guianensis, Chamaecrista ramosa, Protium heptaphyllum, Byrsonima sericea, Myrcia rotundifolia e Marlierea schotti são encontradas na maioria das restingas do Nordeste. No entanto, devido à incipiência dos estudos na Região não foram verificadas espécies endêmicas.The high biodiversity and richness of the coastal zone make it an important ecosystem to be preserved. The aim of this study is to list the species composition of the restinga area (147 ha. of Paiva beach, in Cabo de Santo Agostinho-Pernambuco (08º07'30"S and 35º00'55"W and describe the physiognomies. Floristic survey was carried out for 28 months for all strata. The soil was classified as Quartzarenic Neosoil and two physiognomies were determined: unflooded forest and unflooded open shrubby vegetation. One hundred-twenty-four species were recorded, distributed in 103 genera and 55 families. The families with the highest number of species were: Myrtaceae (11, Cyperaceae (10, Fabaceae (8, Euphorbiaceae (7, Rubiaceae (6 and Asteraceae (5. Anacardium occidentale, Byrsonima sericea

  12. Composição florística da floresta estacional decídua montana de Serra das Almas, CE, Brasil Flora of seasonal deciduous montane forest at Serra das Almas, Ceará State, Brazil

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    Jacira Rabelo Lima

    2009-09-01

    Full Text Available No domínio semi-árido brasileiro, a flora das bacias sedimentares ainda é pouco conhecida, mas os levantamentos já existentes indicam que há grande heterogeneidade florística e fisionômica. Mesmo áreas geográficas próximas podem apresentar dissimilaridade florística. Visando testar esta hipótese, a composição florística e o espectro biológico da floresta estacional decídua de Serra das Almas, estado do Ceará, foram analisados e comparados com os de 14 áreas sedimentares no Nordeste. Foram encontradas 104 espécies e 39 famílias em 1 ha analisado. Fabaceae, Euphorbiaceae, Erythroxylaceae e Myrtaceae foram as famílias com maior riqueza e fanerófitos a forma de vida predominante (87%. Arbóreas e arbustivas representaram 72% das espécies, trepadeiras 15%, subarbustos 6% e herbáceas 7%. A análise de agrupamento da composição dos fanerófitos, usando o índice de Jaccard e as médias de grupo a posteriori, indicou a formação de grupos florísticos entre áreas geográficas mais próximas. Porém, não foi significativo pelo teste de Mantel, o que demonstra a ocorrência de alta heterogeneidade florística mesmo entre áreas geográficas próximas. A flora da floresta da Serra das Almas apresentou maior semelhança com as formações encontradas no planalto da Ibiapaba.In the Brazilian semi-arid region, the flora in the sedimentary basins has been poorly studied, but the few surveys already done indicate great floristic and physiognomic heterogeneity. Even neighboring sites may be floristically different. To test this hypothesis, the floristic composition and the biological spectrum of the seasonal deciduous forest at Serra das Almas, Ceará, was analyzed and compared to those of 14 other northeastern Brazil sedimentary areas. A total of 104 species belonging to 40 families were found at the 1 ha site. Fabaceae, Euphorbiaceae, Erythroxylaceae and Myrtaceae were the families with the most species and phanerophytes the main

  13. Composição florística e estrutura comunitária da floresta de galeria do córrego da Paciência, Cuiabá, (MT Floristic composition and community structure of a gallery forest along the Córrego da Paciência, Cuiabá, Mato Grosso, Brazil

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    Ary Teixeira de Oliveira-Filho

    1989-07-01

    Full Text Available A floresta de galeria de um dos braços do córrego da Paciência, no sopé da chapada dos Guimarães, Mato Grosso (15º 21'S. 55º 49' W, foi inventariada por meio de 67 parcelas de 30m² (0,201 ha, sendo amosdos os indivíduos com circunferência ao nível do solo > 9cm em três setores da floresta; Nascentes, Vereda e Cachoeira. Foram calculados os parâmetros fitossociológicos das espécies e das famílias botânicas para toda a área amostral e para cada um dos três setores da floresta. Foram obtidas medidas de dissimilaridade florística e estrutural entre os três setores amostrais e medidas de dissimilaridade florística entre a floresta do presente estudo e cinco outras florestas riparias do Distrito Federal e dos estados de São Paulo e Mato Grosso. As seis florestas apresentaram entre si índices muito altos de dissimilaridade florística, embora algumas delas apresentassem espécies em comum entre as mais abundantes. Os três setores amostrais mostraram igualmente uma considerável dessemelhança florística e estrutural entre si. O clima, os solos e a geomcrfologia das bacias hidrográficas são evocados como responsáveis pelas diferenças interregionais entre as florestas riparias. Já as dessemelhanças intrarregionais podem ser atribuídas à fertilidade dos solos e, sobretudo, ao regime de água nos solos e nos próprios rios, os quais, por sua vez, variam com a topografia local. Os padrões de distribuição espacial marcadamente diferentes que podem ser observados para várias espécies de árvores podem ser atribuídos à elevada heterogeneidade ambiental, peculiar às florestas de galeria.The gallery forest which occurs along one of the branches of the Córrego da Paciência, southern Mato Grosso, Brazil (15º 21'S, 55º 49'W, was surveyed by 67 plots of 30m² each (0.201 ha. Individuals > 9cm in circumference at ground level were recorded. Three sites of the forest were sampled: Nascentes, Vereda and Cachoeira

  14. Morfo-anatomia da flor de Ocotea puberula (Rich. Nees (Lauraceae Morphology and anatomy of the flower of Ocotea puberula (Rich. Nees (Lauraceae

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    Ismar Sebastião Moscheta

    1999-07-01

    Full Text Available A flor de Ocotea puberula (Rich. Nees foi estudada morfo-anatomicamente de plantas de floresta secundária de Maringá, Paraná, Brasil, uma região crítica com menos de 1% de cobertura vegetal. O estudo também consistiu de observações sobre antese e insetos visitadores de flores dessa espécie. A antese é diurna e a flor pode ser visitada por insetos pertencentes às ordens Hymenoptera, Lepidoptera, Diptera, Thysanoptera e Hemiptera. As tépalas têm epiderme simples e mesofilo parenquimático homogêneo. Os nectários são globosos, parenquimáticos, com predominância de tecido vascular floemático. As anteras são tetrasporangiadas e sua estrutura revela epiderme, endotécio, duas ou três camadas médias e tapete secretor. O gineceu possui estigma com papilas uni ou bicelulares, ovário de parede estruturalmente simples e óvulo anátropo bitegumentado. As flores femininas têm anteras estéreis e as masculinas pistilódio, o que caracteriza a espécie tipicamente como dióica.The morphology and anatomy of the flower of Ocotea puberula (Rich. Nees (Lauraceae are studied in the secondary forest of Maringá, state of Paraná, Brazil, a critical region with less than 1% of its area covered by forests. The study also consists of observations about anthesis and pollination of the species. The anthesis is diurnal and the flower may be visited by insects belonging to the Hymenoptera, Lepidoptera, Diptera, Thysanoptera and Hemiptera orders. The tepals have simple epidermis and homogeneous parenchymatous mesophyll. The nectaries are globose, parenchymatous and the terminal branches closest to the nectary consist principally of phloem. The anthers have four pollen sacs, endothecium, two or three middle layers and secretory tapetum. The gynoecium has stigma with uni or bicellular epidermic papillae, simple ovary wall and anatropous ovule with two integuments. The female flowers have sterile anthers and the male flowers have pistilode, which

  15. Effect of alcoholic extract of guaco (Mikania glomerata on the control of dark rot (Xanthomonas campestris pv. campestris in cauliflower/ Avaliação da eficácia da tintura etanólica de guaco (Mikania glomerata no controle da podridão negra (Xanthomonas campestris pv. campestris em couve-flor

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    Kátia Regina Freitas Schwan-Estrada

    2006-06-01

    Full Text Available With the use of irrigation and new hybrids of cauliflower, it is possible to get production during all the year with hight yield. However, the crop has been affected by diseases, as the dark rot caused by X. campestris pv. campestris. The objective of this research work was to study the potential of Mikania glomerata for the control of this disease. Alcoholic extract 50 ºGL of M. glomerata was evaluated regarding to: in vitro antimicrobial activity through bacterial growth in 100, 250, 500 and 1000 mg L-1 of the alcoholic extract; induction of local or systemic resistance in 25 days old cauliflower, with spray of alcoholic extract concomitantly and three days before the inoculation with the pathogen (water and bordeau mixture were used as control; peroxidases activity in leaves of cauliflower treated and not treated, and harvested concomitantly, 24, 48 and 72 hours after spraying the alcoholic extract and also after inoculation. The alcoholic extract of M. glomerata showed inhibition of the bacterial growth in vitro at the concentrations of 250, 500 and 1000 mg L-1. The concentrations of 500 mg L-1 and 1000 mg L-1 inhibited 24% and 38% of the bacterial growth. This inhibition could be due to antibacterial compounds in the alcoholic extract. An inhibition of the disease in vivo occurred only in the leaves treated with 100 and 500 mg L-1 of alcoholic extract when applied concomitantly with the bacteria. This result was similar to bordeau mixture, indicating a control by direct antimicrobial activity. There was no systemic resistence induction for all treatments. The peroxidases induction was due to infectious pathogen process and not to the treatments with alcoholic extract. The results indicate the potential of M. glomerata alcoholic extract for the preventive control of cauliflower dark rot disease.Com a prática da irrigação e novos híbridos de couve-flor, é possível produzir durante todo o ano e com alta produtividade. Mas, a cultura tem

  16. Modelo causal dos primórdios da ciência do magnetismo

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    Osvaldo Pessoa Júnior

    2010-06-01

    Full Text Available Este artigo apresenta uma breve história do nascimento da ciência do magnetismo, que ocorreu em três continentes distintos de maneira independente. Aplica-se a metodologia dos modelos causais em história da ciência para representar esses caminhos independentes, onde aparece a noção de "gargalo de desenvolvimento". Ênfase é dada para a definição de "avanços generalizados", que reúnem diferentes espécies de avanços e simplicam os diagramas causais. O relato histórico enfoca os avanços na China e na Europa até 1600.This article presents a brief history of the beginning of the science of magnetism, which took place independently in three different continents. The methodology of causal models in the history of science is applied to represent these independent paths, where the notion of "developmental bottleneck" appears. Special attention is given to the definition of "generalized advances", which encompass different species of advances and simplify the causal diagrams. The historical survey covers the advances in magnetism in China and Europe until 1600.

  17. Avaliação de larvicidas de origem microbiana no controle da traça-das-crucíferas em couve-flor Evaluation of microbiological larvicides to control diamondback moth in cauliflower

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    Daniel G.S. Dias

    2004-09-01

    Full Text Available Dois inseticidas biológicos à base de Bacillus thuringiensis subspécies kurstaki (Btk e aizawai (Bta e um inseticida não sistêmico de origem biológica, à base de spinosad, foram avaliados em campo contra a traça-das-crucíferas, Plutella xylostella (L.(Lep.: Plutellidae, em cultivo de couve-flor. O experimento foi realizado em Brazlândia, DF, em uma área de produção regular de hortaliças. A lavoura foi conduzida segundo manejo indicado para a região, sem qualquer intervenção que não o controle da praga. O experimento foi realizado no período de julho a setembro de 2002. O delineamento foi de blocos ao acaso, com quatro tratamentos e quatro repetições. Os produtos foram aplicados em função da média do número de furos produzidos pela praga, presentes nas quatro folhas centrais das plantas, sendo os diferentes tratamentos avaliados semanalmente. Quando a média do número de furos atingia valor igual ou superior a seis, os produtos eram aplicados. Adotando-se este procedimento, aplicou-se três vezes o inseticida spinosad e seis vezes os inseticidas Btk e Bta. Os três tratamentos com inseticidas não diferiram entre si, mas diferiram significativamente da testemunha quanto à produção. As áreas tratadas com Btk produziram 78,1% de cabeças comercializáveis, as tratadas com Bta 76,5% e as tratadas com spinosad 75,5%. No controle houve perda de 34,4% da produção. A utilização dos produtos aumentou a receita da cultura da couve-flor em relação à testemunha, nos valores de R$ 2.505,19 com o Btk, R$ 1.954,55 com o Bta e R$ 1.891,65 com spinosad.Two bioinsecticides based on Bacillus thuringiensis sub species kurstaki (Btk and aizawai (Bta and non-systemic insecticide of biological origin based on spinosad were evaluated on cauliflower crop for diamondback moth, Plutella xylostella (L. (Lep.:Plutellidae control. The experiment was conducted in a vegetable production area of Brazlândia, Brazil. The crop was conducted

  18. Estrutura e composição florística de quatro formações vegetais de restinga no complexo lagunar Grussaí/Iquipari, São João da Barra, RJ, Brasil

    Directory of Open Access Journals (Sweden)

    Assumpção Jorge

    2000-01-01

    Full Text Available Foi estudada a vegetação de restinga do complexo lagunar Grussaí/Iquipari (21°44'S; 41°02'O, que compreende a bacia das lagunas de Grussaí e Iquipari, com aproximadamente 4.800ha. Uma transecção de 25ha (2500x100m foi delimitada no sentido mar/interior e coletas botânicas realizadas entre os anos de 1995 e 1997. As quatro unidades fisionômicas ocorrentes na área foram estudadas e, através do Índice de Valor de Cobertura, foram determinadas as espécies dominantes em cada formação: 1 Formação Praial-Graminóide: Remirea maritima, Ipomoea imperati, Sporobolus virginicus e Chamaecyse thymifolia; 2 Formação Praial com Moitas: Schinus terebinthifolius, Eugenia sulcata, Pilosocereus arrabidae e Cereus fernambucensis; 3 Formação de Clusia: Pera glabrata, Eugenia sulcata, Sideroxylon obtusifolium e Scutia arenicola; 4 Formação Mata de Restinga: Maytenus obtusifolia, Pera glabrata, Protium heptaphyllum e Coccoloba alnifolia. A similaridade florística da área estudada com outras restingas nos Estados do Rio de Janeiro e Espírito Santo não ultrapassou 41%, onde a proximidade geográfica não representou aumento da similaridade. Os resultados ressaltam a variação da flora de restinga ao longo de um pequeno trecho do litoral brasileiro.

  19. Essiac/Flor-Essence (PDQ)

    Science.gov (United States)

    ... of Essiac and Flor Essence as complementary or alternative treatments for cancer? A nurse in Canada first began to promote ... of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that ...

  20. A gênese da causalidade física The genesis of physical causality

    Directory of Open Access Journals (Sweden)

    Michel Paty

    2004-03-01

    Full Text Available As noções ou categorias de causalidade e determinismo acompanharam a formação das ciências modernas e, em primeiro lugar, da física. O uso corrente em nossos dias tende freqüente e erroneamente a confundi-las, nas reconsiderações feitas pela própria física. Propomo-nos esclarecer aqui a primeira dessas noções, mais precisamente a de causalidade física, examinando sua elaboração no início da dinâmica, por meio das primeiras operações e conceituações que acompanham a matematização da mecânica, antes dela ser estendida à física em geral. Veremos como, apoiando-se inteiramente em um aspecto filosófico tradicional da idéia de causalidade (aquele de "causa eficiente", a causalidade física se estabelece em ruptura com o sentido metafísico que lhe era anteriormente associado. Mais do que no Principia de Newton, é na reelaboração por d'Alembert, no Traité de dynamique, das leis do movimento formuladas como princípios e expressas pelo cálculo diferencial, que a idéia de causalidade física é expressamente considerada como indissociável de seu efeito, que é a mudança de movimento. Os respectivos pensamentos de Newton e de d'Alembert sobre as noções de causa e de força estão a esse propósito em oposição, diferindo quanto à natureza propriamente física dessa mudança, considerada por d'Alembert como imanente ao movimento, segundo a causa circunscrita por seu efeito, enquanto ela permanece matemática e metafísica na concepção newtoniana da força externa, como substituto matemático das causas, tal como havia sido proposto antes da mecânica analítica de Lagrange. Foi a concepção física herdada de d'Alembert, que prevaleceria a seguir por meio da mecânica analítica lagrangiana, que permitiu reintegrar física e racionalmente o conceito de força em sua transcrição diferencial euleriana.The notions or categories of causality and determinism have accompanied the formation of modern sciences, and

  1. Semantically enriching folksonomies with FLOR

    OpenAIRE

    Angeletou, Sofia; Sabou, Marta; Motta, Enrico

    2008-01-01

    While the increasing popularity of folksonomies has lead to a vast quantity of tagged data, resource retrieval in these systems is limited by them being agnostic to the meaning (i.e., semantics) of tags. Our goal is to automatically enrich folksonomy tags (and implicitly the related resources) with formal semantics by associating them to relevant concepts defined in online ontologies. We introduce FLOR, a mechanism for automatic folksonomy enrichment by combining knowledge from WordNet and on...

  2. Variações estruturais e florísticas do carrasco no planalto da Ibiapaba, estado do Ceará

    OpenAIRE

    F. S. de ARAÚJO; F. R. MARTINS; SHEPHERD G. J.

    1999-01-01

    Carrasco é uma vegetação xerófila arbustiva densa alta, ainda pouco conhecida, que ocorre no domínio semi-árido do nordeste do Brasil, sobre Areias Quartzosas distróficas profundas, entre 700 e 900 m de altitude, no planalto da Ibiapaba e chapada do Araripe. Este trabalho tem por objetivo conhecer a estrutura e a composição da comunidade lenhosa e possíveis relações dessas variações espaciais com variáveis pedológicas. Em Jaburuna (3°54'34"S, 40°59'24"W, cerca de 830 m de altitude), município...

  3. Morfo-anatomia da flor de Ocotea puberula (Rich.) Nees (Lauraceae) Morphology and anatomy of the flower of Ocotea puberula (Rich.) Nees (Lauraceae)

    OpenAIRE

    Ismar Sebastião Moscheta; Luiz Antonio de Souza

    1999-01-01

    A flor de Ocotea puberula (Rich.) Nees foi estudada morfo-anatomicamente de plantas de floresta secundária de Maringá, Paraná, Brasil, uma região crítica com menos de 1% de cobertura vegetal. O estudo também consistiu de observações sobre antese e insetos visitadores de flores dessa espécie. A antese é diurna e a flor pode ser visitada por insetos pertencentes às ordens Hymenoptera, Lepidoptera, Diptera, Thysanoptera e Hemiptera. As tépalas têm epiderme simples e mesofilo parenquimático homog...

  4. Composição florística e estrutura do estrato inferior da floresta de várzea na área de proteção ambiental Ilha do Combu, município de Belém, estado do Pará

    OpenAIRE

    Bernardo Antônio Rodrigues Maués; Mário Augusto Gonçalves Jardim; Fábio de Jesus Batista; Tonny David Santiago Medeiros; Adriano da Costa Quaresma

    2011-01-01

    O estrato inferior é formado pela regeneração das espécies arbóreas, arbustivas, herbáceas, epífitas e lianas formando um nicho ecológico de vital importância para o estabelecimento e desenvolvimento da floresta. Com o objetivo de analisar a composição florística e a estrutura do estrato inferior da floresta de várzea na APA Ilha do Combu, Belém, Pará, foram alocadas 50 parcelas de 50 x 4 m e divididas em 25 subparcelas de 2 x 2 m. Foram identificadas e quantificadas todas as espécies com Diâ...

  5. Composição florística do componente arbóreo de um trecho de Floresta Atlântica na Área de Proteção Ambiental da Serra da Capoeira Grande, Rio de Janeiro, RJ, Brasil Floristic survey of the tree layer in an area of Atlantic Rainforest in Serra da Capoeira Grande Environmental Protection Area, Rio de Janeiro State, Brazil

    Directory of Open Access Journals (Sweden)

    Gustavo Luna Peixoto

    2004-03-01

    Full Text Available A Área de Proteção Ambiental (APA da Serra da Capoeira Grande (22º59'03"S e 43º38'59"W tem área total de 80ha e é um dos últimos remanescentes florestais com pau-brasil (Caesalpinia echinata Lam. no município do Rio de Janeiro. Além disso, ocorrem na área outras três espécies ameaçadas de extinção: Cariniana ianeirensis R. Knuth, Acosmium lentiscifolium Spreng. e Machaerium incorruptible (Vell. Fr. All. ex Benth. O levantamento fitossociológico foi realizado por meio do método dos quadrantes, tendo sido alocados 200 pontos e tendo-se como critério de inclusão 15cm de circunferência do tronco a 1,30m de altura do solo. A composição florística é o resultado desta amostragem acrescida de coletas feitas durante caminhadas no fragmento, totalizando 29 famílias, 58 gêneros e 69 espécies. As famílias que apresentaram maior número de espécies foram: Leguminosae (13, Myrtaceae (6, Euphorbiaceae (5, Bignoniaceae, Bombacaceae, Celastraceae, Flacourtiaceae, Moraceae, Rubiaceae e Solanaceae (3. Analisando a similaridade florística entre a APA da Serra da Capoeira Grande e outras 18 áreas florestais do Rio de Janeiro, observou-se maior identidade florística entre a área estudada e florestas de baixada localizadas próximas ao mar. Todas as florestas reuniram-se com um baixo nível de similaridade, refletindo a diversidade florística das florestas do Rio de Janeiro.The 80-hectare site (22º59'03"S and 43º38'59"W, is one of the last forest remnants in Rio de Janeiro municipality, where brazilwood (Caesalpinia echinata Lam. occurs naturally. Furthermore, three other endangered species occur in this area: Cariniana ianeirensis R. Knuth, Acosmium lentiscifolium Spreng., and Machaerium incorruptible (Vell. Fr. All. ex Benth. Trees were sampled according to the point-centered-quarter method. The inclusion criteria was PBH >15cm; a total of 200 points were surveyed. The floristic composition was comprised of the sampled

  6. Estádio sucessional e fatores geográficos como determinantes da similaridade florística entre comunidades florestais no Planalto Atlântico, Estado de São Paulo, Brasil Successional stage and geographic features determine floristic similarity among Atlantic Forest remnants, São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Giselda Durigan

    2008-03-01

    Full Text Available A análise das relações de similaridade florística entre comunidades geralmente conduz ao estabelecimento de padrões, condicionados por fatores diversos que determinam a ocorrência ou não das espécies em diferentes locais. Em busca de tais padrões, foram analisadas as relações de similaridade florística entre comunidades florestais localizadas na região do Planalto de Ibiúna, estado de São Paulo, Brasil. Incluíram-se na análise 21 fragmentos florestais e seis sítios em uma Reserva Florestal contínua, sendo que a composição florística e a estrutura da comunidade arbórea (DAP mínimo 5 cm em cada local foram amostradas pelo método de quadrantes. Aplicaram-se dois métodos de análises multivariadas: 1 Análise de Correspondência Destendenciada (DCA, com base no índice de similaridade de Sørensen; e 2 Divisão Hierárquica Dicotômica (TWINSPAN. A similaridade florística foi mais elevada entre comunidades em estádios sucessionais semelhantes, especialmente se estivessem geograficamente próximas. Há um gradiente florístico associado à latitude, indicando tratar-se de uma região de transição entre biomas. Nos sítios situados na face norte da região de estudo estão presentes espécies que também ocorrem no cerradão e em floresta estacional semidecidual, enquanto nos sítios situados na face sul prevalecem espécies características da floresta ombrófila densa.Analysis of floristic similarity relationships between plant communities can detect patterns of species occurrence and also explain conditioning factors. Searching for such patterns, floristic similarity relationships among Atlantic Forest sites situated at Ibiúna Plateau, São Paulo state, Brazil, were analyzed by multivariate techniques. Twenty one forest fragments and six sites within a continuous Forest Reserve were included in the analyses. Floristic composition and structure of the tree community (minimum dbh 5 cm were assessed using the point

  7. Flor Yeast: New Perspectives Beyond Wine Aging.

    Science.gov (United States)

    Legras, Jean-Luc; Moreno-Garcia, Jaime; Zara, Severino; Zara, Giacomo; Garcia-Martinez, Teresa; Mauricio, Juan C; Mannazzu, Ilaria; Coi, Anna L; Bou Zeidan, Marc; Dequin, Sylvie; Moreno, Juan; Budroni, Marilena

    2016-01-01

    The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the aging of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen and fermentable carbon sources, these yeast produce aggregates of floating cells and form an air-liquid biofilm on the wine surface, which is also known as velum or flor. This behavior is due to genetic and metabolic peculiarities that differentiate flor yeast from other wine yeast. This review will focus first on the most updated data obtained through the analysis of flor yeast with -omic tools. Comparative genomics, proteomics, and metabolomics of flor and wine yeast strains are shedding new light on several features of these special yeast, and in particular, they have revealed the extent of proteome remodeling imposed by the biofilm life-style. Finally, new insights in terms of promotion and inhibition of biofilm formation through small molecules, amino acids, and di/tri-peptides, and novel possibilities for the exploitation of biofilm immobilization within a fungal hyphae framework, will be discussed. PMID:27148192

  8. Flor Yeast: New Perspectives Beyond Wine Aging

    Science.gov (United States)

    Legras, Jean-Luc; Moreno-Garcia, Jaime; Zara, Severino; Zara, Giacomo; Garcia-Martinez, Teresa; Mauricio, Juan C.; Mannazzu, Ilaria; Coi, Anna L.; Bou Zeidan, Marc; Dequin, Sylvie; Moreno, Juan; Budroni, Marilena

    2016-01-01

    The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the aging of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen and fermentable carbon sources, these yeast produce aggregates of floating cells and form an air–liquid biofilm on the wine surface, which is also known as velum or flor. This behavior is due to genetic and metabolic peculiarities that differentiate flor yeast from other wine yeast. This review will focus first on the most updated data obtained through the analysis of flor yeast with -omic tools. Comparative genomics, proteomics, and metabolomics of flor and wine yeast strains are shedding new light on several features of these special yeast, and in particular, they have revealed the extent of proteome remodeling imposed by the biofilm life-style. Finally, new insights in terms of promotion and inhibition of biofilm formation through small molecules, amino acids, and di/tri-peptides, and novel possibilities for the exploitation of biofilm immobilization within a fungal hyphae framework, will be discussed. PMID:27148192

  9. "Flor do meu coração"

    OpenAIRE

    Araujo, Guilherme Leonardo

    2013-01-01

    Resumo: Esta dissertação apresenta análise etnomusicológica do hinário "Flor do meu coração". Os hinos que compõem este hinário são atribuídos ao dirigente da igreja Céu do Paraná - primeira igreja do culto Santo Daime filiada ao Centro Eclético da Fluente Luz Universal Raimundo Irineu Serra (CEFLURIS) no Estado do Paraná. A igreja Céu do Paraná está localizada no distrito de Bateias, município de Campo Largo, na região metropolitana de Curitiba. Com o objetivo de compreender como o hinário "...

  10. Análise da composição florística e fitossociológica da floresta nacional do Tapajós com o apoio geográfico de imagens de satélites Analysis of the floristic and phytosociologic composition of Tapajós national forest with geographic support of satellite images

    Directory of Open Access Journals (Sweden)

    Fernando Del Bon Espírito-Santo

    2005-06-01

    Full Text Available O objetivo desse trabalho foi analisar a distribuição da cobertura vegetal de diversas porções da Floresta Nacional (FLONA do Tapajós (FNT, no Pará, através de atributos florísticos e fitossociológicos apoiados por imagens de satélites, em áreas de floresta primária (FP e floresta secundária (FS. Para isso foram amostrados 35 transectos de 10 m ' 250 m em áreas de FP de alto e baixo platô, incluindo também as áreas alteradas por de corte florestal seletivo de madeira e 29 transectos de 10 m ' 100 m em áreas de FS em vários estágios regenerativos. Em cada um desses transectos foram levantadas informações dendrométricas como DAP (Diâmetro à Altura do Peito, altura total (AT e altura comercial (AC, além de localização dos indivíduos arbóreos dentro das amostras. Os diâmetros de inclusão para as áreas de floresta primária e secundária foram de 10 cm e 3 cm, respectivamente. Foram inventariados 7666 indivíduos (6607 árvores ou arbustos e 1059 palmeiras em uma área amostral de 11,65 ha, distribuídos em diferentes regiões da FNT. Foram identificadas em áreas de FP e FS 190 espécies de árvores, arbustos e palmeiras distribuídas entre 153 gêneros e 46 famílias. Nas FP e FS foi encontrado um índice de diversidade de Shannon-Wiener (H' de 4,44 e 4,09 nits.indivíduos-1, respectivamente, indicando uma alta diversidade biológica para essas duas fitofisionomias. Através de análises multivariadas foi possível concluir que existe uma diferença florística e quantitativa na porção norte, centro e sul da FLONA. As áreas de FS apresentaram uma grande heterogeneidade ambiental, dificultando o processo de agrupamento das suas fases sucessionais. Através desse trabalho foi possível concluir que o apoio das imagens ETM+/Landsat e RADARSAT-1 otimizou o processo de amostragem da FNT e possibilitou a análise espacial das regiões com maior diferenciação florística e fitossociológica da Floresta Nacional

  11. Reavaliação taxonômica de Colletotrichum guaranicola Albuq. agente causal da antracnose do guaranazeiro Taxonomic reavaluation of Colletotrichum guaranicola Albuq. causal agent of guarana anthracnose

    Directory of Open Access Journals (Sweden)

    Jânia Lília da Silva Bentes

    2004-01-01

    Full Text Available Foi realizada uma reavaliação morfológica de estruturas reprodutivas e de infecção do agente causal da antracnose do guaranazeiro (Paullinia cupana var. sorbilis, visando confirmar a identidade do patógeno. Os resultados reforçam o reconhecimento da espécie Colletotrichum guaranicola Albuq., como um novo taxon dentro do gênero Colletotrichum.A morphological study of reproductive and infection structures of the anthracnosis fungus of guaranazeiro (Paullinia cupana var. sorbilis, has confirmed the pathogen identity as Colletotrichum guaranicola Albuq., a new specie in the Colletotrichum genera.

  12. Composição florística e a conservação de floresta secundárias na serra da Cantareira, São Paulo, Brasil. Floristic composition and conservation of old secondary Forest in the serra Cantareira in São Paulo, South-Eastern Brazil.

    Directory of Open Access Journals (Sweden)

    Frederico Alexandre Roccia Dal Pozzo ARZOLLA

    2011-06-01

    Full Text Available Florestas secundárias estão seriamente ameaçadas pela expansão urbana na região metropolitana. Alguns remanescentes são protegidos, principalmente em parques estaduais e municipais, mas a maioria dessas florestas está sob risco de supressão pela contínua expansão de áreas urbanas. O objetivo deste trabalho foi caracterizar a composição florística do componente arbóreo de trecho de floresta, em estágio médio a avançado de regeneração no Parque Estadual da Cantareira, São Paulo (SP. Foram realizadas caminhadas nos traçados antigo e novo da Linha de Transmissão Guarulhos–Anhanguera, num total aproximado de 11 km de extensão. A amostragem foi realizada no período de 2006 a 2010. No levantamento florístico, foram identificadas 179 espécies, pertencentes a 54 famílias e 127 gêneros. As famílias com maior riqueza de espécies foram Fabaceae (19 espécies, Myrtaceae (18, Lauraceae (16 e Rubiaceae (15 e os gêneros mais ricos, Ocotea e Myrcia (6, Eugenia (5 e Maytenus, Mollinedia e Nectandra com quatro espécies cada. Foram registradas dez espécies consideradas ameaçadas de extinção, sendo quatro espécies na lista de São Paulo e seis na lista da IUCN. Uma delas, Mollinedia oligotricha, é considerada presumivelmente extinta. A similaridade florística encontrada com outros remanescentes florestais da Região Metropolitana de São Paulo e arredores variou entre 11% a 38%. Florestas secundárias apresentam uma considerável riqueza de espécies, incluindo espécies ameaçadas de extinção. Foram discutidas as pressões incidentes sobre esses remanescentes florestais, bem como possíveis estratégias para a sua conservação.Secondary forests are seriously threatened by urban expansion in the metropolitan region of São Paulo. Some remnants are protected, mainly in state or municipal parks, but most of these forests are in immanent danger of being destroyed by the continual expansion of urban areas. The aim of this

  13. Florística e estrutura da vegetação arbustivo-arbórea do sub-bosque de um povoamento de Eucalyptus grandis W. Hill ex Maiden em Viçosa, MG, Brasil Floristic and structure of tree-shrub vegetation in understory of Eucalyptus grandis W. Hill ex Maiden stands, in Viçosa, MG, Brazil

    Directory of Open Access Journals (Sweden)

    Priscila Bezerra de Souza

    2007-01-01

    Full Text Available Este estudo teve como objetivo conhecer a composição florística e a estrutura da vegetação arbustivo-arbórea no sub-bosque de povoamento de Eucalyptus grandis na Reserva Florestal da Mata do Paraíso, em Viçosa, MG. Foram demarcadas 40 parcelas contíguas de 5 x 5 m, dispostas em transectos de 5 x 50 m, nas quais foram medidos, identificados e classificados quanto às síndromes de dispersão de sementes e às categorias sucessionais. Foram amostrados 884 indivíduos pertencentes a 50 espécies e 22 famílias. As espécies que se destacaram em valor de importância foram Psychotria sessilis, Siparuna guianensis e Erythroxylum pelleterianum, principalmente com relação à elevada densidade. Predominaram em densidade espécies secundárias tardias com síndromes de dispersão zoocórica. A riqueza florística encontrada pode ser considerada alta, por se tratar de sub-bosque de Eucalyptus grandis, e reflete o potencial da utilização dessa espécie como catalisadora de vegetação arbustivo-arbórea nativa em áreas degradadas.The objective of the present study was to analyze the floristic composition and structure of tree-shrub vegetation in understory of Eucalyptus grandis W. former Hill Maiden, Paraíso Forest Reserve, Viçosa, MG. Forty adjacent 5 x 5 m plots were demarcated and arranged in 5 x 50 m transects, in which individuals were measured, identified and classified in relation to seed dispersal syndromes and successional categories. Eight hundred and eighty four individuals belonging to 50 species and 22 families were recorded. The species with the highest Importance Value were Psychotria sessilis, Siparuna guianensis and Erythroxylum pelleterianum, particularly with regard to high density. Late secondary species with zoochorous dispersal syndromes prevailed in density. The founded floristic richness can be considered high for a Eucalyptus grandis understory and reflects the potential for using the species as catalyst for native

  14. ITS-rDNA phylogeny of Colletotrichum spp. causal agent of apple Glomerella leaf spot Filogenia por ITS-rDNA de Colletotrichum spp., agente causal da mancha foliar da Gala em macieira

    Directory of Open Access Journals (Sweden)

    Diorvania Ribeiro Giaretta

    2010-04-01

    Full Text Available Several diseases have affected apple production, among them there is Glomerella leaf spot (GLS caused by Colletotrichum spp. The first report of this disease in apple was in plants nearby citrus orchards in São Paulo State, Brazil. The origin of this disease is still not clear, and studies based on the molecular phylogeny could relate the organisms evolutionarily and characterize possible mechanisms of divergent evolution. The amplification of 5.8S-ITS (Internal Transcribed Spacer of rDNA of 51 pathogenic Colletotrichum spp. isolates from apples, pineapple guava and citrus produced one fragment of approximately 600 bases pairs (bp for all the isolates analyzed. The amplified fragments were cleaved with restriction enzymes, and fragments from 90 to 500bp were obtained. The sequencing of this region allowed the generation of a phylogenetic tree, regardless of their hosts, and 5 isolated groups were obtained. From the "in silico" comparison, it was possible to verify a variation from 93 to 100% of similarity between the sequences studied and the Genbank data base. The causal agent of GLS is nearly related (clustered to isolates of pineapple guava and to the citrus isolates used as control.A produção de maçã vem sendo comprometida pela ocorrência de muitas doenças, entre as quais se destaca a Mancha Foliar de Glomerella (MFG, causada por Colletotrichum spp. O primeiro relato dessa doença em maçã foi registrado em plantas próximas a pomares de citrus no Estado de São Paulo, Brasil. A origem da MFG ainda não está bem clara, e estudos baseados na filogenia permitirão relacionar o organismo evolutivamente, possibilitando caracterizar possíveis mecanismos divergentes de evolução. A amplificação da região 5.8S-ITS (espaçador interno transcrito do rDNA de 51 isolados de Colletotrichum patogênicos em de maçã, goiabeira serrana e citrus produziu um fragmento de aproximadamente 600 pares de bases (pb para todos os isolados analisados

  15. Use of solaria to predict weed density and floristic composition in no-till cropping systems Uso de solaria na predição da densidade de ervas daninhas e da composição florística no sistema de semeadura direta

    Directory of Open Access Journals (Sweden)

    Pablo Antonio Calviño

    2006-03-01

    Full Text Available The objective of this work was to evaluate the efficiency of a new method, developed for predicting density and floristic composition of weed communities in field crops. Based on the use of solaria (100 mm transparent plastic tarps lying on the soil to stimulate weed seedlings emergence, the method was tested in Tandil, Argentina, from 1998 to 2001. The system involved corn and sunflower in commercial no-till system. Major weeds in the experiments included Digitaria sanguinalis, Setaria verticillata and S. viridis, which accounted for 98% of the weed community in the three years of experiments since 1998. Large numbers of Tagetes minuta, Chenopodium album and Ammi majus were present in 2001. Comparison of weed communities under solaria with communities in field crops indicated that the method is useful for predicting the presence and density of some major weed species, at both high and low densities, of individuals in areas of 10 ha using only five solaria. Low density of weed species makes the method particularly useful to help deciding the time for herbicide applications to avoid soil contamination.O objetivo deste trabalho foi avaliar a eficiência de novo método, desenvolvido para predizer a densidade e a composição florística das comunidades de plantas daninhas. O método é baseado no uso de solaria (plástico transparente de 100 mm sobre o solo, a fim de estimular o aparecimento de ervas daninhas, e foi testado em Tandil, Argentina, de 1998 a 2001. O sistema envolve milho e girassol, em cultivos comerciais em semeadura direta. As principais espécies experimentadas foram Digitaria sanguinalis, Setaria verticillata e S. viridis, que responderam por 98% da comunidade nos três anos de experiência. Números altos de Tagetes minuta, Chenopodium album e Ammi majus estavam presentes em 2001. A comparação de comunidades de ervas daninhas sob solaria com comunidades fora de solaria indicou que o método é útil para predizer a presença e

  16. Procesamiento de imágenes para reconocimiento de daños causados por plagas en el cultivo de Begonia semperflorens Link & Otto (flor de azúcar

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    Camilo Andrés Cáceres Flórez

    2015-07-01

    Full Text Available En este trabajo se presentan los resultados obtenidos en el reconocimiento de plagas utilizando la visión de máquina por computador como elemento de diagnóstico. La captura de las imágenes se realizó por medio de un agente robótico aéreo (drone equipado con una cámara, lo que permitió capturar las imágenes del estado de las hojas de un cultivo de la planta conocida como ‘flor de azúcar’ (Begonia semperflorens. Estas imágenes fueron procesadas utilizando técnicas de visión de máquina con el fin de identificar el posible ataque de plagas en el cultivo. Las técnicas utilizadas corresponden a filtros morfológicos, difuminado gaussiano y filtrado HSL. Como resultado principal de este trabajo se detectaron perforaciones de hojas ocasionadas por el ataque de plagas, específicamente babosas, caracoles, arañas rojas y minadoras

  17. Composição florística e estrutura do estrato inferior da floresta de várzea na área de proteção ambiental Ilha do Combu, município de Belém, estado do Pará

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    Bernardo Antônio Rodrigues Maués

    2011-06-01

    Full Text Available O estrato inferior é formado pela regeneração das espécies arbóreas, arbustivas, herbáceas, epífitas e lianas formando um nicho ecológico de vital importância para o estabelecimento e desenvolvimento da floresta. Com o objetivo de analisar a composição florística e a estrutura do estrato inferior da floresta de várzea na APA Ilha do Combu, Belém, Pará, foram alocadas 50 parcelas de 50 x 4 m e divididas em 25 subparcelas de 2 x 2 m. Foram identificadas e quantificadas todas as espécies com Diâmetro à Altura do Peito (DAP d" 10 cm. Calcularam-se a diversidade, densidade e frequência relativas, categoria de tamanho relativa e regeneração natural relativa. Foram amostrados 22.221 indivíduos, 67 famílias, 153 gêneros e 223 espécies, e o índice de Shannon (H' foi de 3,72 nat/ind e a equabilidade (J', de 0,69. Fabaceae, Malvaceae e Arecaceae destacaram-se em riqueza de espécies e Euterpe oleracea e Virola surinamensis em densidade relativa, categoria de tamanho relativa e regeneração natural relativa. O hábito arbóreo apresentou o maior número de espécies e indivíduos nas classes de tamanhos 1 e 2. Os mecanismos de adaptação e a produção de frutos estão relacionados com a diversidade da área, onde as espécies com estratégias mais eficientes são dominantes e mais representativas quantitativamente na comunidade.

  18. Florística e fitossociologia da vegetação de um campo sujeito à arenização no sudoeste do Estado do Rio Grande do Sul, Brasil Floristics and phytosociology of grassland vegetation subject to sandy desertification in southwestern Rio Grande do Sul State, Brazil

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    Elisete Maria de Freitas

    2009-06-01

    Full Text Available Extensas áreas de campo nativo do sudoeste do Rio Grande do Sul são suscetíveis ao processo de arenização, que ocorre em áreas de fragilidade pedológica, tendo influência de interferência antrópica e fatores abióticos. Com o objetivo de testar a variação da cobertura vegetal e a dinâmica da arenização no tempo e conforme a influência da distância da encosta, foi desenvolvido um estudo florístico e fitossociológico em áreas de campo nativo sob pastejo. Duas subáreas, diferentes quanto ao processo da arenização, foram selecionadas no município de São Francisco de Assis, RS. O levantamento florístico apontou a ocorrência de 102 espécies, distribuídas em 25 famílias. No estudo fitossociológico, 35 quadros permanentes de 0,25 m² em cada subárea foram dispostos em diferentes distâncias da encosta do morro. Foram registradas as coberturas das espécies vegetais, do mantilho e do solo exposto em três períodos. Dados sobre riqueza e diversidade de espécies e formas de vida foram avaliados por análise de variância, via testes de aleatorização, considerando o fator temporal e o espacial (distância da encosta. Houve maior redução da diversidade específica e da cobertura vegetal na subárea 1 (com menor cobertura vegetal conforme a variação temporal. Na subárea 2 (com maior cobertura vegetal, o aumento do solo exposto e a conseqüente redução da cobertura vegetal tiveram maior influência da distância da encosta. A alteração da cobertura vegetal e a expansão da arenização observadas ao longo do tempo são resultado da influência conjunta da dinâmica pluviométrica, do tipo solo, da presença de encostas dos relevos tabulares com pouca vegetação e da contínua pressão de pastejo.Extensive areas of native grassland in southwestern Rio Grande do Sul are susceptible to sandy desertification, which occurs in pedologically fragile areas influenced by anthropic interference and abiotic factors. A

  19. Rendimento, composição tecidual e musculosidade da carcaça de cordeiros Santa Inês alimentados com diferentes níveis de feno de flor-de-seda na dieta Yield, tissue composition and carcass muscularity of Santa Inês lambs fed diets with different ratios of forage sorghum hay to silk flower hay

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    Ana Valéria Mello de Souza Marques

    2007-06-01

    Full Text Available Foi avaliada a inclusão de níveis crescentes de feno de flor-de-seda (Calotropis procera SW (FFS em substituição ao feno de sorgo forrageiro (Sorghum bicolor, L. (FSF na dieta e seus possíveis efeitos sobre os rendimentos verdadeiro, biológico e comercial, a perda ao resfriamento, o rendimento dos cortes, a composição tecidual e a musculosidade da carcaça de cordeiros Santa Inês. Foram utilizados 24 cordeiros (machos não-castrados distribuídos em um delineamento inteiramente casualisado, com quatro tratamentos (relações FSF:FFS: 100:0, 66:33, 33:66 e 0:100. Os animais foram abatidos com 30,0 (±0,4 kg ou aos 70 dias de experimento. Não houve efeito das relações FSF:FFS na dieta sobre os rendimentos biológico, verdadeiro e comercial, sendo obtidos valores médios de 53,17; 45,97 e 44,34%, respectivamente. Foram observadas diferenças significativas no peso vivo ao abate, no peso de corpo vazio, nos pesos de carcaça quente e de carcaça fria, no rendimento dos cortes, na composição tecidual e na musculosidade da carcaça. À exceção dos cortes paleta e perna, as variáveis apresentaram valores mais elevados quando fornecidos os menores níveis de FFS na dieta. O feno de flor-de-seda pode ser utilizado na alimentação de cordeiros para produção de carne em proporções de até 16,5% da dieta (33% da fração volumosa, pois não ocasiona prejuízo à qualidade da carcaça.This study evaluated the effects of different dietary ratios of forage sorghum (Sorghum bicolor L hay (FSH to silk flower hay (Calotropis procera SW (SFH on true, biological, and retail carcass yields, carcass cooling losses, retail cut yields, tissue composition and carcass muscularity of Santa Inês lambs. Twenty-four intact male lambs were assigned to one of the following four treatments: 100:0 FSH:SFH, 66:33 FSH:SFH , 33:66 FSH:SFH, or 0:100 FSH:SFH in a completely randomized design (six animals/treatment. Animals were slaughtered at 30.0±0.4 kg of

  20. Flor yeast: new perspectives beyond wine aging

    OpenAIRE

    Legras, Jean Luc; Jaime MORENO-GARCIA; Zara, Severino; Zara, Giacomo; Garcia-Martinez, Teresa; Mauricio, Juan C.; Mannazzu, Ilaria; Coi, Anna L.; Bou Zeidan, Marc; Dequin, Sylvie; Moreno, Juan; Budroni, Marilena

    2016-01-01

    The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the aging of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen and fermentable carbon sources, these yeast produce aggregates of floating cells and form an air–liquid biofilm on the wine surface, which is also known as velum o...

  1. Flor yeast: new perspectives beyond wine ageing

    OpenAIRE

    Jean-luc eLegras; Jaime eMoreno García; Severino eZara; Giacomo eZara; Teresa eGarcia Martinez; Ilaria Maria Mannazzu; Juan Carlos Mauricio; Anna Lisa Coi; Marc eBou Zeidan; Sylvie eDequin; Juan eMoreno; Marilena eBudroni

    2016-01-01

    The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the ageing of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen and fermentable carbon sources, these yeast produce aggregates of floating cells and form an air-liquid biofilm on the wine surface, which is also known as the velum...

  2. Flor yeast: new perspectives beyond wine aging

    OpenAIRE

    Legras, Jean Luc; Moreno-Garcia, Jaime; Zara, Severino; Zara, Giacomo; Garcia-Martinez, Teresa; Mauricio, Juan C.; Mannazzu, Ilaria; Coi, Anna L.; Bou Zeidan, Marc; Dequin, Sylvie; Moreno, Juan; Budroni, Marilena

    2016-01-01

    Pas de clé UT The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the aging of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen andfermentable carbon sources, these yeast produce aggregates of floating cells and form an air–liquid biofilm on the wine surface, which is also kno...

  3. Dinâmica inicial da composição florística de uma área restaurada na região do Pontal do Paranapanema, São Paulo, Brasil Initial dynamics of floristic composition in a restoresd area in the region of Pontal do Paranapanema, São Paulo state, Brazil

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    Elisangela Ronconi Rodrigues

    2010-10-01

    Full Text Available O Pontal do Paranapanema, extremo oeste do Estado de São Paulo, é marcado pela recente devastação florestal, e ações visando à recuperação de áreas onde outrora havia cobertura florestal tornam-se indispensáveis para a conservação da biodiversidade na região, principalmente quando se trata de áreas de Reserva Legal ou Preservação Permanente. Diante do exposto, esta pesquisa teve como objetivo analisar a dinâmica inicial da composição florística em uma área de Reserva Legal restaurada. O trabalho foi realizado no assentamento Nova Esperança, Município de Euclides da Cunha Paulista, em uma área de 26,75 ha. O levantamento das espécies foi realizado pelo método de parcelas (16 parcelas de 20 x 30 m em duas fases distintas do plantio, e as análises foram feitas utilizando-se o software Fitopac. Os resultados evidenciaram diminuição da biodiversidade pela alta mortalidade de espécies, levando à conclusão de que em projetos de restauração as intervenções são necessárias para a manutenção do plantio mesmo em sua fase inicial.The Pontal do Paranapanema Region is located in the western range of the State of São Paulo is characterized by recent forest destruction and actions are needed for forest restorations and conservation of biodiversity in the region, principally when if treated of areas of Legal Reserve or Permanent Preservation. Before of the exposed this research had it objective analyze the dynamics initial from floristic composition an area of Legal Reserve restored. This work was realized into the Nova Esperança settlement, city of Euclides da Cunha Paulista, an area of 26,75 ha. The lifting from the species was realized at method of parcels (16 parcels of 20 x 30 m into two phases differentiate of the plantation, and the analisys have been using Fitopac software.The results they show only one decrease from biodiversity by high mortality of species, taking the conclusive what projects of restoration

  4. Diversidade fenotípica e patogênica de Colletotrichum, agente causal da antracnose em mangueira, e identificação de espécie

    OpenAIRE

    I.M.R.S. Serra; R.S.B. Coelho; G.M.G. Ferraz; A.V.V. Montarroyos; D.S. Silva

    2011-01-01

    O presente trabalho teve como objetivo estudar a diversidade fenotípica e patogênica de 40 isolados de Colletotrichum obtidos de mangueira no Nordeste do Brasil e identificar diferentes espécies desse fitopatógeno, agente causal de antracnose, através da análise da seqüência da região ITS do rDNA. Quanto à caracterização morfológica e cultural, as colônias dos isolados apresentaram diversidade em relação à cor e aspecto, sendo mais comum à cor branco-cinza, característica de Colletotrichum gl...

  5. Composição e riqueza florística do componente arbóreo da Floresta Atlântica submontana na região de Imbaú, Município de Silva Jardim, RJ Floristic composition and richness of the tree community in a submontane Atlantic Forest in the Imbaú region, Silva Jardim, Rio de Janeiro

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    Fabrício Alvim Carvalho

    2006-09-01

    Full Text Available O presente trabalho teve por objetivo avaliar a composição florística arbórea de um trecho de Floresta Atlântica submontana na região de Imbaú, Silva Jardim, RJ. Esta região formava um contínuo florestal que foi fragmentado há mais de 50 anos por práticas agropecuárias. Cinco fragmentos foram selecionados e em cada um deles foram alocadas quatro parcelas de 100×5 m. Todas as árvores vivas com DAP > 5 cm foram amostradas e identificadas. No hectare amostrado foram encontradas 161 espécies distribuídas por 39 famílias. A similaridade florística entre os fragmentos foi alta, com índice de Morisita variando de 0,36 a 0,79. As famílias Leguminosae, Lauraceae e Rubiaceae apresentaram a maior riqueza de espécies. A comparação florística com uma floresta madura da região indicou forte decréscimo na riqueza de espécies que, juntamente com a elevada densidade de espécies secundárias iniciais, indicam que estas matas se encontram em estádio sucessional secundário. Analisando a similaridade florística entre a região de Imbaú e outras 17 florestas do Rio de Janeiro, observou-se maior similaridade com as florestas submontanas mais próximas geograficamente. Devido ao avançado processo de fragmentação e à importância ecológica destes fragmentos para a manutenção da flora e fauna, sugere-se que a região de Imbaú deva ser prioritária em programas de conservação e manejo de áreas de Mata Atlântica.This study aimed to evaluate tree floristic composition of the submontane Atlantic Forest in the Imbaú region, Silva Jardim, Rio de Janeiro. About 50 years ago, the forest fragmentation process was begun in this region due to farming practices. Five forest remnants were selected and four plots (100×5 m were systematically located in each one. All trees with dbh > 5 cm were sampled and identified. In the one-hectare sample area, 161 species in 39 families were sampled. Species similarity was high between fragments

  6. A arma e a flor: formação da organização policial, consenso e violência The gun and the flower: police organization, consensus and violence

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    José Vicente Tavares dos Santos

    1997-05-01

    Full Text Available O objetivo do texto é analisar sob um enfoque sociológico a organização policial, sua função como máquina repressiva do Estado e as estratégias da construção de uma legitimidade consensual sobre o papel da Polícia na sociedade moderna e contemporânea. O estudo também propõe uma investigação dirigida a um pluralismo teórico/metodológico, através do qual a internacionalização da visão sociológica, mediatizada pelo processo de globalização, torna possível se compreender a polícia em uma sociedade ainda em processo de consolidação democrática.The objective of this text is to work out a sociological approach about the police organization, their function as a repressive machine of the State and the strategies of the construction for a consensual legitimity about the role of the Police in the modern and contemporary society. The study also proposes as investigation directed to a theoretical-methodological pluralism, through which the internationalization of the sociological view, mediated by the globalization process, makes possible the understanding of the police in a society yet in a process of a democratic consolidation.

  7. Composição florística e estrutura da regeneração natural de floresta secundária de várzea baixa no estuário amazônico

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    Gama João Ricardo Vasconcellos

    2002-01-01

    Full Text Available O objetivo do presente estudo foi analisar a estrutura da regeneração natural de uma floresta explorada de várzea baixa localizada no município de Afuá, no norte do Estado do Pará. Foram amostradas 25 subparcelas de 100 m², nas quais foram medidos a altura de todos os indivíduos das espécies arborescentes com altura (h superscript three 0,30 m e diâmetro a 1,30 m do nível do solo (DAP superscript three 3,0 m e DAP < 15,0 cm, além de ter sido realizada a identificação botânica. Foram amostrados 13.380 indivíduos/ha, distribuídos em 63 espécies, 51 gêneros e 23 famílias botânicas. As espécies mais importantes da fitocenose foram: Euterpe oleracea, Astrocaryum murumuru, Crudia bracteata, Gustavia augusta e Inga edulis. Mais de 60% das espécies estudadas apresentaram padrão de distribuição agregado, e o índice de diversidade de Shannon-Weaver (H' foi de 3,05.

  8. Composição florística e estrutura do componente arbóreo de uma Floresta Paludosa na planície costeira da bacia do rio Itaguaré, Bertioga, SP, Brasil. Floristic composition andstructure of an arboreal component of the Paludal Forest in the coastal plain of the Itaguaré river basin, Bertioga (São Paulo state, Brazil

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    Celia Regina de Gouveia SOUZA

    2012-06-01

    Full Text Available As Florestas Paludosas costeiras ou “caxetais” ocorrem no Domínio Atlântico, em geral associadas a depressões paleolagunares, cujos terrenos são permanentemente encharcados. Essas florestas se caracterizam por apresentar elevada densidade de indivíduos da espécie Tabebuia cassinoides (Lam. DC., conhecida popularmente por “caxeta”. O presente estudo foi desenvolvido em uma Floresta Paludosa situada na planície costeira do rio Itaguaré, município de Bertioga, Baixada Santista, Estado de São Paulo. A composição florística e a estrutura fitossociológica foram investigadas através da amostragem por parcelas, sendo incluídos todos os indivíduos com 10 cm ou mais de diâmetro a 1,3 m de altura do peito (DAP. Foram registradas 20 espécies e 11 famílias botânicas, resultando em uma densidade total de 450 ind./ha-1. A família com maior riqueza de espécies foi Myrtaceae, com quatro espécies. A análise de similaridade indicou dois grupos florísticos. Tabebuia cassinoides foi, de fato, a espécie mais importante, apresentando grande densidade e dominância de indivíduos, o que reforça sua posição de espécie indicadora deste tipo vegetacional, conforme difundido na literatura. The coastal Paludal Forest or “Caxetal” occurs on the Atlantic Domain, associated to wetlands within palaeolagoonal depressions. It is characterized by a high density of individuals of Tabebuia cassinoides (Lam. DC., which is popularly known as “caxeta”. A Paludal Forest located in the Itaguaré river coastal plain, in the municipality of Bertioga, Santos Lowland, São Paulo State, Brazil was studied. The floristic composition and phytossociological structure was investigated through a plot method including all individuals with diameter at 1.3 m (DBH ≥ 10 cm. A total of 20species and 11 botanic families were sampled, resulting in a total density of 450 ind./ha-1. Myrtaceae showed the highest species richness. The similarity index indicated

  9. Causal mapping

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    2006-01-01

    The lecture note explains how to use the causal mapping method as well as the theoretical framework aoosciated to the method......The lecture note explains how to use the causal mapping method as well as the theoretical framework aoosciated to the method...

  10. Genes diferencialmente expressos em cana-de-açúcar inoculada com Xanthomonas albilineans, o agente causal da escaldadura da folha Diferential gene expression in sugar cane infected with Xanthomonas albilineans, causal agent of leaf scald

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    Karina Maia Dabbas

    2006-09-01

    Full Text Available A escaldadura da folha, causada pela bactéria Xanthomonas albilineans colonizadora do xilema, é uma das principais doenças da cana-de-açúcar. A sintomatologia na fase crônica é caracterizada principalmente pelo aparecimento de uma faixa branca paralela à nervura central da folha, que evolui até queimar totalmente, sendo também observado brotação de gemas laterais no colmo. Neste trabalho, a técnica de macroarranjos de cDNA foi empregada para o estudo da expressão de 3.575 ESTs (espressed sequence tags em folhas de cana-de-açúcar. Foram utilizadas duas variedades, uma resistente (SP82-1176 e outra suscetível (SP78-4467 a Xanthomonas albilineans as quais foram infectadas mecanicamente por ferimentos. As membranas dos macroarranjos foram confeccionadas a partir de ESTs de bibliotecas de folha e cartucho de cana-de-açúcar provenientes do projeto SUCEST e hibridizadas contra sondas de cDNA de plantas infectadas e controle marcadas com isótopos radioativos. Analisando os resultados dos macroarranjos foi possível verificar um comportamento diferenciado para cada variedade durante o ataque do patógeno. Após realizadas análises estatísticas identificamos na variedade resistente ESTs com expressão induzida relacionadas com biossíntese de isoprenoides, proteínas LRR transmembrânica, "ziper" de leucina, lignificação, tolerância ao frio, diferenciação de plastídeos, sistemas de defesa e de adaptação da planta ao meio ambiente. As ESTs reprimidas na variedade resistente foram àquelas relacionadas com genes responsáveis pela síntese de proteínas do controle da expansão da parede celular, detoxificação e transporte de auxina. Na variedade susceptível foram reprimidas ESTs relacionadas a genes de proteínas das respostas de defesa da planta, biossíntese de Etileno e regulação da transcrição.The leaf scald disease, caused by the xylem-invading pathogen Xanthomonas albilineans, is one of the most devastating

  11. Caracterização florística da vegetação sobre afloramento rochoso na Estação Experimental de Itapeva, SP, e comparação com áreas de campos rupestres e de altitude. Floristic characterization on rocky outcrop in the Itapeva Experimental Station, SP, and comparison with areas of rocky grasslands and high-altitude grasslands.

    Directory of Open Access Journals (Sweden)

    Silvana Cristina Pereira Muniz de SOUZA

    2011-06-01

    Full Text Available A classificação de comunidades vegetais nem sempre é tarefa fácil, principalmente quando se trata de tipos de vegetação pouco estudados. Esse é o caso davegetação sobre afloramento rochoso da Estação Experimental de Itapeva – EEI, situada no sudoeste do Estado de São Paulo, região que abriga remanescentes de Cerrado e Mata Atlântica. Visando caracterizar e classificar essa vegetação, foram realizadas coletas mensais de material botânico no período de agosto de 2008 a fevereiro de 2010. A lista de espécies obtida foi comparada com a de campos rupestres e de altitude brasileiros. As comparações foram realizadas por meio de análise de agrupamento, “TWINSPAN” e “NMS”. Foram encontradas 135 espécies, 48 famílias e 108 gêneros. As famílias mais representativas foram Fabaceae, Asteraceae, Bignoniaceae, Myrtaceae, Melastomataceae, Poaceae, Apocynaceae, Sapindaceae e Orchidaceae. A análise de agrupamento com os dados de distribuição de riqueza entre famílias sugeriu maior afinidade florística entre o afloramento rochoso estudado e os campos rupestres. Para os dados de composição de espécies, os diferentes métodos de ligação agruparam a área de estudo ora com campos de altitude ora com campos rupestres. A “NMS” evidenciou o caráter contínuo da variação florística, mas reiterou a maior similaridade entre a área de estudo e os campos rupestres. A “TWINSPAN” reforçou essa hipótese e apontou a família Fabaceae e as espécies Miconia albicans (Sw. Steud. e Periandra mediterranea (Vell. Taub como indicadoras de campos rupestres. O tipo de solo, formado a partir de rochas areníticas, constitui o fator determinante mais plausível para as relações florísticas encontradas.The classification of vegetation communities is not an easy task, especially regarding less studied vegetation types. This is the case for rocky outcrop vegetation in the Itapeva Experimental Station – EEI, located in the

  12. Nutritional value of silk flower hay for lambs Valor nutritional do feno de flor-de-seda para cordeiros

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    Aderbal Marcos de Azevêdo Silva

    2010-12-01

    nutrientes e aumentou a conversão alimentar e o coeficiente de digestibilidade de todos os nutrientes. O balanço de nitrogênio foi semelhante em todos os níveis de feno de flor-de-seda, embora tenha havido tendência de redução na retenção do nitrogênio nos níveis 66 e 100% de feno de flor-de-seda. Nos níveis 0 e 33% de feno de flor-de-seda na dieta, a ingestão de matéria seca (170 e 180 g/dia, o ganho médio diário de peso (84 e 89 g/kg0,75 e a conversão alimentar (4,99 e 5,02 foram satisfatórios. O feno de flor-de-seda pode representar até 16,5% da ingestão total ou 33% do volumoso da dieta de cordeiros.

  13. Heliconia psittacorum: hospedeira de Mycosphaerella fijiensis, agente causal da sigatoka-negra da bananeira First reporter of Mycosphaerella fijiensis on Heliconia psittacorum leaves

    OpenAIRE

    Luadir Gasparotto; J. Clério R. Pereira; Urben, Arailde F.; Rogério E Hanada; Mirza C. N. Pereira

    2005-01-01

    Em setembro de 2003, em Manaus, Amazonas, foram observadas manchas foliares, muito semelhantes àquelas de sigatoka-negra causada por Mycosphaerella fijiensis em folhas de Heliconia psittacorum. Efetuou-se o isolamento do patógeno e, para o teste de patogenicidade, foi utilizada a técnica de inoculação cruzada com os isolados de H. psittacorum e de bananeira (Musa spp.) da cv. Prata Anã. Em ambas as espécies o teste foi positivo. Com o auxílio do microscópio óptico, da literatura disponível e ...

  14. Alma Flor Ada and the Quest for Change

    Science.gov (United States)

    Manna, Anthony, L.; Hill, Janet; Kellogg, Kathy

    2004-01-01

    Alma Flor Ada, a folklorist, novelist, scholar, teacher, and children's book author has passionate dedication to education for social justice, equality, and peace. As a faculty member at the University of San Francisco, Ada has developed programs that help students and others transform their lives and has written several bilingual legends and…

  15. Diversidade fenotípica e patogênica de Colletotrichum, agente causal da antracnose em mangueira, e identificação de espécie

    Directory of Open Access Journals (Sweden)

    I.M.R.S. Serra

    2011-03-01

    Full Text Available O presente trabalho teve como objetivo estudar a diversidade fenotípica e patogênica de 40 isolados de Colletotrichum obtidos de mangueira no Nordeste do Brasil e identificar diferentes espécies desse fitopatógeno, agente causal de antracnose, através da análise da seqüência da região ITS do rDNA. Quanto à caracterização morfológica e cultural, as colônias dos isolados apresentaram diversidade em relação à cor e aspecto, sendo mais comum à cor branco-cinza, característica de Colletotrichum gloeosporioides. Não foram observadas variações expressivas na morfologia dos 40 isolados. Os conídios apresentaram-se, predominantemente, hialinos e unicelulares, com formato variando de bastonete para cilíndrico. Todos os isolados produziram apressórios variados em formato e quantidade e apenas 10 isolados apresentaram setas. Para efeito do crescimento micelial e taxa de crescimento foi possível classificar os isolados em sete grupos. Vinte e dois isolados exibiram taxa de crescimento >10mm/dia, considerada típica da espécie C. gloeosporioides. Os isolados foram patogênicos em folhas destacadas de mangueira, induzindo sintomas de antracnose, na forma de manchas escuras levemente deprimidas, e apresentando variações quanto à agressividade. Na identificação específica, baseada na análise da seqüência ITS do DNA ribossomal, 36 isolados amplificaram com o oligonucleotídeos CgInt, específico para C. gloeosporioides e o ITS4, Os isolados CM1, CM4, CM5 e CM10, não amplificaram produtos para nenhum dos oligonucleotídeos específicos, sendo identificados como Colletotrichum spp. Os resultados desse trabalho demonstraram que isolados de Colletotrichum, obtidos de mangueira, apresentam ampla variabilidade morfofisiológica e patogênica. E que, possivelmente, existe mais de uma espécie de Colletotrichum que causa antracnose em mangueira no Nordeste do Brasil.

  16. CONTROLE QUÍMICO DOS PULG��ES Mysus persicae E Brevicoryne brassicae NA CULTURA DA COUVE-FLOR COM INSETICIDAS APLICADOS NA FORMA DE ESGUICHO CHEMICAL CONTROL OF APHIDS Mizus persicae AND Brevicoryne brassicae ON CAULIFLOWER WITH INSECTICIDES APPLIED IN TRANSPLANT HOLES

    Directory of Open Access Journals (Sweden)

    Selby Pereira dos Santos

    2007-09-01

    Full Text Available

    Avaliou-se o controle químico dos pulgões Mysus persicae e Brevicoryne brassicae, em couve-flor, através dos inseticidas Confidor 700 GRDA e Confidor 200 SC, na área experimental da Escola de Agronomia da Universidade Federal de Goiás em maio de 1998. Foram utilizadas duas dosagens para cada um dos inseticidas, um inseticida padrão (Tamaron Br e uma testemunha. Confidor 700 GRDA e Confidor 200 SC, ambos em duas dosagens, foram aplicados em uma única vez nas covas de transplante, com um pulverizador costal, utilizando bico de esguicho. A avaliação dos resultados de M. persicae constou de contagens de ninfas e adultos em folhas escolhidas ao acaso, nas plantas da linha central das parcelas, 35 dias após os tratamentos. A mesma metodologia foi utilizada para a avaliação de B. brassicae 48 dias após o tratamento. O tratamento com Tamaron Br foi aplicado na forma de pulverizações semanais, ocorrendo as avalia

  17. Riqueza de espécies, estrutura e composição florística de uma floresta secundária de 40 anos no leste da Amazônia Species richness, structure, and floristic composition of a 40 years old secondary forest in Eastern Amazon

    Directory of Open Access Journals (Sweden)

    Sâmyrams Carim

    2007-06-01

    Full Text Available A perda de florestas naturais devido a pressões antrópicas levou as florestas secundárias a ocupar uma grande proporção de áreas no leste da Amazônia. Com o objetivo de conhecer as características de uma comunidade arbórea e a estrutura populacional das espécies mais representativas, foram investigadas a riqueza de espécies, a estrutura e a composição florística de uma floresta secundária de 40 anos no município de Bragança (01°11'S e 46°40'W, Estado do Pará, Brasil. A amostragem contou com todos os indivíduos de espécies arbóreas (exceto Arecaceae com DAP > 5 cm em 150 quadrados de 10×10 m. Foram registrados 2.934 indivíduos em 154 espécies, 101 gêneros e 40 famílias. A densidade foi de 1.956,00 ± 643,45 ind ha-1 e a área basal de 17,358 ± 7,952 m² ha-1 com um índice de diversidade de Shannon de 4,030 nats. ind.-1. As espécies com a maior abundância de indivíduos foram Myrcia bracteata, Casearia arborea e Maprounea guianensis. As com maior área basal foram Tapirira guianensis, Croton matourensis e Maprounea guianensis. A riqueza de espécies adaptou-se ao modelo de distribuição lognormal apenas para área basal e não para número de indivíduos. Em 40 anos de sucessão, esta floresta mostra uma grande diversidade de espécies e baixa área basal.The loss of natural forests due to the anthropic pressure carried the secondary forests to occupy great proportions of areas in East of Amazon. With the aim to known the characteristics of a arboreal community and the population structure of the most representative species, it were investigated species richness, structure, and floristic composition of a 40 years old secondary forest in the municipality of Bragança (01°11'S and 46°40'W, Pará State, Brazil. It was sampled all individuals of arboreal species (except Arecaceae with DBH > 5 cm in 150 plots of 10×10 m. It was registered 2,934 individuals in 154 species, 101 genera and 40 families. The density was 1

  18. Composição florística e síndromes de polinização e de dispersão da mata do Sítio São Francisco, Campinas, SP, Brasil Floristic composition and pollination and dispersion syndromes in the Sítio São Francisco forest, Campinas, São Paulo State, Brazil

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    Luiza Sumiko Kinoshita

    2006-06-01

    Full Text Available Foi realizado o levantamento florístico da floresta estacional semidecídua localizada no Sítio São Francisco, bem como a caracterização das síndromes de polinização e de dispersão das espécies. Foram encontrados um total de 46 famílias, 116 gêneros e 148 espécies (50 árvores, 35 lianas, 26 arbustos e 37 ervas. As famílias com maior riqueza de espécies arbóreas foram Euphorbiaceae (8, Fabaceae (7, Meliaceae (6 e Rutaceae (5. Entre as lianas, as famílias mais ricas foram Bignoniaceae (13, Sapindaceae (5 e Malpighiaceae (3; entre as herbáceas, Poaceae (8 e Asteraceae (5; e entre as arbustivas, Piperaceae (7 e Rubiaceae (5. As síndromes de polinização e de dispersão mais freqüentes foram melitofilia (73% e zoocoria (63%, ambas predominantes no sub-bosque, sendo que algumas espécies apresentaram mais de uma síndrome de polinização. A análise de similaridade com outros sete fragmentos do município mostrou a mata do Sítio São Francisco em posição intermediária entre as formações higrófilas e as estacionais semidecíduas, e a ocorrência de algumas espécies exclusivas de árvores e de lianas.A floristic survey of the seasonal semi-deciduous forest located in the Sítio São Francisco was undertaken, together with studies of pollination and dispersion syndromes of the species. A total of 46 families, 116 genera and 148 species (50 trees, 35 lianas, 26 shrubs and 37 herbs was found. The richest families in number of arboreal species were Euphorbiaceae (8, Fabaceae (7, Meliaceae (6 and Rutaceae (5. The lianas were distributed mainly in the following families: Bignoniaceae (13, Sapindaceae (5 and Malpighiaceae (3, while in the herbaceous plants, the richest families were Poaceae (8 and Asteraceae (5, and among the shrubs were Piperaceae (7 and Rubiaceae (5. The most frequent pollination and dispersion syndromes were respectively, melittophily (73% and zoochory (63%, both predominating in the sub-arboreal stratum. More

  19. Composição florística da comunidade infestante em gramados de Paspalum notatum no município de Assis, SP Floristic composition of the weed community in Paspalum notatum Flügge turfgrasses in Assis, SP

    Directory of Open Access Journals (Sweden)

    C.D.G. Maciel

    2008-03-01

    Full Text Available Os gramados de Paspalum notatum são os mais disseminados no Brasil, constituindo diferentes locais e propósitos. A infestação por plantas daninhas acarreta perda de qualidade estética quando a finalidade do gramado é ornamental. Com o objetivo de caracterizar a comunidade infestante em gramados de P. notatum no município de Assis/SP, foi realizado entre os meses de junho e julho de 2004 um levantamento florístico em áreas ensolaradas e sombreadas, sob copas de árvores. Cem amostras de 0,50 x 0,50 m foram coletadas nas duas condições de luminosidade (50 em áreas ensolaradas e 50 em áreas sombreadas, a partir das quais foram calculados os parâmetros freqüência, densidade, abundância, freqüência relativa, densidade relativa, abundância relativa e índice de valor de importância. Ao todo, foram identificadas 45 espécies de plantas daninhas, distribuídas em 15 famílias; Asteraceae apresentou o maior número de espécies nas condições ensolaradas e sombreadas. As espécies mais importantes nas áreas ensolaradas foram: Oxalis latifolia > Desmodium incanum > Cyperus flavus > Cyperus diffusus > Cyperus brevifolius; e nas áreas sombreadas: C. brevifolius > Alternanthera tenella > D. incanum > Elephantopus mollis > C. flavus. Para 80,0% das amostragens, a massa seca total da parte aérea das espécies de plantas daninhas não sofreu influência das condições ensolarada ou sombreada, constituindo uma produção máxima de aproximadamente 150 kg ha-1 para ambas as condições.The Paspalum notatum are the most disseminated turfgrasses in Brazil, constituting different sites and purposes.Weed infestation can lead to loss of turfgrass aesthetic quality when its purpose is ornamental.To characterize the weed community in P. notatum turfgrasses in Assis-SP, a floristic survey was carried out in sunny and shades areas, under tree canopies, during June and July, 2004. One hundred samples of 0.50 x 0.50 m collected from sunny and

  20. Florística e estrutura da comunidade arbórea de um remanescente florestal ripário no município de Guariba, Estado de São Paulo, Brasil. Floristic and structure of the arboreal community of riparian forest remain at Guariba municipality, São Paulo State, Brazil.

    Directory of Open Access Journals (Sweden)

    Nicole Maria Marson DONADIO

    2009-06-01

    Full Text Available O conhecimento sobre a composição eestrutura de comunidades florestais é fundamentalpara embasar ações de conservação e restauração.O objetivo deste trabalho foi realizar olevantamento florístico e descrever a estrutura dacomunidade arbórea de um remanescente florestallocalizado no município de Guariba, Estado de SãoPaulo. Foram alocadas 30 parcelas de 10 x 10 m,para amostrar os indivíduos arbóreos e arbustivoscom diâmetro à altura do peito (DAP ³ 5 cm.Foram encontradas 54 espécies, pertencentes a 47gêneros, distribuídos em 32 famílias botânicas,com índice de diversidade (H’ de 2,67 eequabilidade (J de 0,20. As famílias Meliaceae eFabaceae apresentaram maior riqueza em espécies.Calophyllum brasiliensis, Astronium graveolens,Scheffera morototoni, Xylopia aromatica eProtium widgrenii destacaram-se como as espéciesde maior valor de importância. Foram amostrados420 indivíduos. A presença de espécies do cerradosugere condição de ecótono e a dominância de umaespécie higrófila indica saturação hídrica em parteda área. A distribuição dos indivíduos em classesde tamanho revelou uma comunidade emregeneração com a maioria dos indivíduos com até15,0 cm de DAP e distribuídos entre 7 e 14,9 m,e com estoques de jovens tanto das espéciespioneiras como secundárias podendo garantir ofuturo da comunidade. Em termos sucessionais aárea estudada encontra-se em estádio de médiopara avançado.Knowledge of the composition andstructure of arboreal communities is paramount forconservation and restoration efforts. The mainobjectives of this study were to characterize thearboreal species floristic composition and describethe structure of the arboreal community of aremaining forest located at the municipality ofGuariba, State of São Paulo. Thirty plots of 10 x 10 mwere allocated. In each plot, diameter and heightwere measured for each individual tree withdiameter at breast height (dbh ³ 5 cm. Fifty-fourspecies were

  1. Causality Principle

    OpenAIRE

    Chi, Do Minh

    2001-01-01

    We advance a famous principle - causality principle - but under a new view. This principle is a principium automatically leading to most fundamental laws of the nature. It is the inner origin of variation, rules evolutionary processes of things, and the answer of the quest for ultimate theories of the Universe.

  2. L-Histidine Inhibits Biofilm Formation and FLO11-Associated Phenotypes in Saccharomyces cerevisiae Flor Yeasts

    OpenAIRE

    Marc Bou Zeidan; Giacomo Zara; Carlo Viti; Francesca Decorosi; Ilaria Mannazzu; Marilena Budroni; Luciana Giovannetti; Severino Zara

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of FLO11 which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling FLO11 alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce FLO11p. The flor strains generally metabolized amino acids and ...

  3. L-Histidine Inhibits Biofilm Formation and FLO11-Associated Phenotypes in Saccharomyces cerevisiae Flor Yeasts

    OpenAIRE

    Marc Bou Zeidan; Giacomo Zara; Carlo Viti; Francesca Decorosi; Ilaria Mannazzu; Marilena Budroni; Luciana Giovannetti; Severino Zara

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of Flo11p which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling Flo11p alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce Flo11p. The flor strains generally metabolized amino acids and dipeptides...

  4. Gastronomia sensual: análise simbólica de A festa de Babette e Dona Flor e seus dois maridos = Sensual gastronomy: symbolic analysis of Babetes fiest and Dona Flor e seus dois maridos

    Directory of Open Access Journals (Sweden)

    Rocha, Gilmar

    2009-01-01

    Full Text Available O texto apresenta uma análise simbólica sobre a representação do gênero feminino dramatizada nos filmes Dona Flor e seus dois maridos (1976 e A festa de Babette (1987. Ambientados em contextos socio-históricos diferentes, tais filmes podem ser vistos como “etnografias” que falam do imaginário religioso e do ethos cultural protestante na Dinamarca de fins do século 19 e do sincretismo afro-brasileiro da primeira metade do século 20. O ponto de vista da antropologia simbólica, alimentada pelas contribuições teóricas de Clifford Geertz, Marcel Mauss, Victor Turner e Roberto DaMatta, orienta a interpretação dos filmes a partir dos códigos culturais da culinária (comida, da corporalidade (sexualidade e da religiosidade (puritanismo e sincretismo. Destaca-se, nessas “etnografias fílmicas”, o modo como os sistemas da dádiva e da carnavalização que as estruturam convergem para um mesmo campo de significação. A estratégia metodológica adotada consiste em comparar os filmes tendo por base a estrutura conceitual dos “dramas sociais”

  5. Análise das variações florísticas e estruturais da comunidade arbórea de um fragmento de floresta semidecídua às margens do rio Capivari, Lavras-MG Analysis of the floristic and structural variations of a tree community in a tropical semideciduous forest fragment on the margins of the Capivari river, Lavras, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Josival Santos Souza

    2003-04-01

    Full Text Available Realizou-se um estudo das variações florísticas e estruturais da comunidade arbórea em um fragmento de Floresta Estacional Semidecídua situado às margens do rio Capivari, em Lavras, Minas Gerais, com o objetivo de analisar as correlações entre variáveis ambientais (edáficas, topográficas e morfométricas do fragmento e a distribuição das espécies arbóreas. Procurou-se, também, ampliar o conhecimento sobre a composição florística e a estrutura fitossociológica das comunidades arbóreas da região do alto rio Grande. As espécies arbóreas foram amostradas em coletas extensivas na área e intensivas dentro de 28 parcelas de 20 ´ 20 m, tendo sido considerados apenas os indivíduos com DAP > 5 cm. As parcelas foram distribuídas em cinco transeções, dispostas paralelamente à inclinação predominante do terreno. As variáveis ambientais foram obtidas por meio do levantamento topográfico do fragmento e de análises químicas e granulométricas de amostras dos solos. As correlações entre distribuição das abundâncias das espécies e as variáveis ambientais nas parcelas foram avaliadas por análise de correspondência canônica (CCA. A listagem florística registrou 166 espécies, sendo 140 encontradas dentro das parcelas. A comunidade arbórea apresentou um elevado índice de diversidade de Shannon (H' = 4,258 nats/indivíduo, correlacionado à baixa dominância ecológica (alta equabilidade de Pielou, J' = 0,862 e, possivelmente, à alta heterogeneidade ambiental local. A CCA demonstrou que a heterogeneidade ambiental do fragmento é caracterizada principalmente pela topografia acidentada e pelas variações de fertilidade, granulometria e regime hídrico dos solos, sendo este último o mais fortemente correlacionado com a distribuição das espécies. Muitas espécies arbóreas mostraram clara preferência por dois habitats: a baixa encosta, com solos mais úmidos e férteis, e a alta encosta, com solos menos úmidos e

  6. A rede de causalidade da insegurança alimentar e nutricional de comunidades quilombolas com a construção da rodovia BR-163, Pará, Brasil The causality of nutrition and food insecurity of quilombola communities with the construction of the BR-163, highway, Pará, Brazil

    OpenAIRE

    Denise Oliveira e Silva; Ana Felisa Hurtado Guerrero; Camilo Hurtado Guerrero; Luciano Medeiros de Toledo

    2008-01-01

    OBJETIVO: Trata-se da descrição de resultados baseados na elaboração de um modelo de determinação causal de forma participativa e abrangente, realizada em seis comunidades quilombolas no município de Santarém, no Estado do Pará, sobre a rede de causalidade da insegurança alimentar e nutricional com a abertura da Rodovia BR-163. MÉTODOS: O processo investigativo utilizou métodos de abordagem sócio-antropológica tendo como base o desenvolvimento de um modelo de causalidade construído por meio d...

  7. A rede de causalidade da insegurança alimentar e nutricional de comunidades quilombolas com a construção da rodovia BR-163, Pará, Brasil The causality of nutrition and food insecurity of quilombola communities with the construction of the BR-163, highway, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Denise Oliveira e Silva

    2008-08-01

    Full Text Available OBJETIVO: Trata-se da descrição de resultados baseados na elaboração de um modelo de determinação causal de forma participativa e abrangente, realizada em seis comunidades quilombolas no município de Santarém, no Estado do Pará, sobre a rede de causalidade da insegurança alimentar e nutricional com a abertura da Rodovia BR-163. MÉTODOS: O processo investigativo utilizou métodos de abordagem sócio-antropológica tendo como base o desenvolvimento de um modelo de causalidade construído por meio da realização de grupos focais com representantes da comunidade. RESULTADOS: Os resultados do estudo demonstraram que a utilização de abordagens participativas estimula a auto-estima da comunidade e o empoderamento sobre os fatores que determinam seus problemas. O modelo causal construído revela que a insegurança alimentar e nutricional, para as comunidades, estabelece que fatores históricos relacionados à posse da terra e ao seu uso atual baseado em práticas predatórias, são os aspectos fundamentais na compreensão da rede de determinação causal da insegurança alimentar e nutricional. CONCLUSÃO: O racismo e suas nuances sociais têm contribuído para a invisibilidade social dessas comunidades nas políticas públicas brasileiras. As comunidades quilombolas se consideram em insegurança alimentar e nutricional e indicam que a abertura da Rodovia BR-163 pode ser uma ameaça ao etno-desenvolvimento sustentável na região. E referem que o desenvolvimento econômico esperado com a abertura desta rodovia, se não for realizado com base na participação da comunidade, pode aumentar a fome, a miséria e o racismo.OBJECTIVE: This work describes results based on the participative and encompassing development of a model of causal determination done in six quilombola communities of Santarém, Pará State, regarding the causality of food and nutrition insecurity with the construction of the BR-163 highway. METHODS: The research process

  8. Levantamento florístico e fitofisionomia da lagoa Figueira e seu entorno, planície alagável do alto rio Paraná, Porto Rico, Estado do Paraná, Brasil - DOI: 10.4025/actascibiolsci.v25i1.2091 Floristic survey and phytophysiognomy of the Figueira pond in the upper Paraná River floodplain, in Porto Rico, state of Paraná, Brazil - DOI: 10.4025/actascibiolsci.v25i1.2091

    Directory of Open Access Journals (Sweden)

    Maria Conceição de Souza

    2003-04-01

    Full Text Available Foi realizada uma caracterização botânica da lagoa Figueira (planície alagável do alto rio Paraná, Porto Rico, Estado do Paraná, Brasil, a 22o45’36’’S e 53ol5’56’’W, empregando-se levantamentos florísticos e perfis fitofisionômicos em diferentes períodos fluviométricos, além de uma carta batimétrica e análise do solo. O levantamento florístico resultou no reconhecimento de 36 famílias, 75 gêneros e 89 espécies. As famílias de maior riqueza específica foram Poaceae (14 espécies, seguida por Cyperaceae e Euphorbiaceae (oito cada. O porte predominante pertenceu ao herbáceo (79,78% das espécies e, quanto à forma biológica, houve predominância das terrestres (50,56% e das anfíbias (37,08%. A fitofisionomia, com predominância de herbáceas, apresenta diferenciações entre as margens e ao longo da lagoa, havendo uma considerável diminuição da cobertura vegetal no período de águas altas. Essa lagoa foi considerada um corpo de água raso, com solo tipo argilosoA botanical characterization of the Figueira pond (Upper Paraná River floodplain, in Porto Rico, State of Paraná, Brazil, at 22o45’36’’ S and 53ol5’56’’ W has been carried out using floristic surveys and phytophysiognomic profiles, in different water periods, together with a bathymetric chart and a soil analysis. The floristic survey resulted in 36 families, 75 genera and 89 species. The families with more specific richness were Poaceae (14 species, followed by Cyperaceae and Euphorbiaceae (eight each. The highest habit incidence belonged to the herbaceous (79,78% of the species and, concerning the biological form, there was predominance of the terrestrial (50,56% and amphibious ones (37,08%. The phytophysiognomy, with predominance of herbaceous, shows differentiation between the banks and along the pond, with a considerable decrease of the vegetal covering in the high water periods. This pond was considered a shallow body of water, with

  9. Resistência de variedades comerciais de cana-de-açúcar ao agente causal do raquitismo-da-soqueira Resistance of sugarcane commercials cultivars to causal agent of ratoon stunting disease

    OpenAIRE

    Paulo Roberto Gagliardi; Luis Eduardo Aranha Camargo

    2009-01-01

    O raquitismo-da-soqueira (RSD), causado pela bactéria Leifsonia xyli subsp. xyli, é uma das mais importantes doenças da cana-de-açúcar nas regiões produtoras do mundo. O presente trabalho teve como objetivo avaliar o grau de resistência de 10 variedades comerciais RB de cana-de-açúcar mais a variedade CB 49-260, a qual foi incluída como padrão suscetível. O trabalho visou avaliar os danos amostrados em campo pelo peso das parcelas em função da relação entre a produtividade de parcelas inocula...

  10. Florística e estrutura do componete arbustivo-arbóreo de mata de restinga arenosa no Parque Estadual de Itapeva, Rio Grande do Sul

    Directory of Open Access Journals (Sweden)

    Robson Santos

    2012-12-01

    Full Text Available Para ampliar o conhecimento sobre as matas de Restinga arenosa no Rio Grande do Sul, foi realizado estudo florístico e fitossociológico do componente arbustivo-arbóreo de um capão de Restinga do Parque Estadual de Itapeva (PEVA. Neste estudo foi usado o método de parcelas, incluindo todos os indivíduos com DAS (diâmetro a altura do solo mínimo de 2,5 cm e totalizando uma área de 0,5 ha. A composição florística resultou em riqueza total de 81 espécies. A densidade total arbustivo-arbórea no capão foi de 4.240 ind/ha. A família com maior riqueza específica foi Myrtaceae e, entre as espécies com maior valor de importância, estão Myrsine umbellata Mart. e Sorocea bonplandii (Baill. W. C. Burger. Na regeneração natural as 10 primeiras espécies acumularam 54% da regeneração natural total, com índices que variaram de 13,5% a 0,2%. A elevada riqueza observada evidenciou a contribuição da "Porta de Torres" como importante corredor migratório das espécies atlânticas na vegetação do Rio Grande do Sul, agregando novas informações sobre a florística e estrutura comunitária da Restinga do Rio Grande do Sul. Os resultados apresentados contribuirão para posteriores estudos de dinâmica no PEVA e para programas de manejo, preservação e recuperação ambiental.

  11. Flor de Citrus aurantium e ansiedade pré-operatória

    Directory of Open Access Journals (Sweden)

    Mahmood Akhlaghi

    2011-12-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: Reduzir a ansiedade é muito importante antes da operação. A visita no pré-operatório e a utilização de pré-medicação são os métodos mais populares para se atingir esse objetivo, mas o papel da pré-medicação ansiolítica permanece incerto e os efeitos colaterais no pós-operatório podem partir de uma pré-medicação de rotina. Citrus aurantium é usado como medicina alternativa em alguns países para tratar a ansiedade. Recentemente, o papel ansiolítico dessa planta medicinal foi estabelecido em um estudo realizado em modelo animal. O objetivo deste estudo foi avaliar o efeito ansiolítico da flor de Citrus aurantium sobre a ansiedade pré-operatória. MÉTODOS: Foram estudados 60 pacientes ASA I submetidos a uma pequena cirurgia. Em um desenho randomizado e duplo-cego, dois grupos de 30 pacientes receberam uma das seguintes MPA oral duas horas antes da indução da anestesia: 1 Citrus aurantium destilado 1 mL.kg-1 (Grupo C; 2 solução salina 1 mL.kg-1 como placebo (Grupo P. A ansiedade foi medida antes e após pré-medicação com o Inventário de Ansiedade Traço-Estado (IDATE e a Escala de Ansiedade e Informação Pré-Operatória de Amsterdam (APAIS antes da operação. RESULTADOS: Após pré-medicação, tanto o IDATE quanto as escalas APAIS estavam diminuídos no Grupo C (p < 0,05, embora não tenham apresentado alterações significativas no Grupo P. CONCLUSÕES:Citrus aurantium pode mostrar-se eficaz na redução da ansiedade pré-operatória em cirurgias de pequeno porte.

  12. Resistência de variedades comerciais de cana-de-açúcar ao agente causal do raquitismo-da-soqueira Resistance of sugarcane commercials cultivars to causal agent of ratoon stunting disease

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Gagliardi

    2009-07-01

    Full Text Available O raquitismo-da-soqueira (RSD, causado pela bactéria Leifsonia xyli subsp. xyli, é uma das mais importantes doenças da cana-de-açúcar nas regiões produtoras do mundo. O presente trabalho teve como objetivo avaliar o grau de resistência de 10 variedades comerciais RB de cana-de-açúcar mais a variedade CB 49-260, a qual foi incluída como padrão suscetível. O trabalho visou avaliar os danos amostrados em campo pelo peso das parcelas em função da relação entre a produtividade de parcelas inoculadas e não inoculadas artificialmente com a bactéria. Os resultados mostraram que as variedades RB 72 454, RB 83 5486, RB 86 7515, RB 92 5211, RB 92 5268, RB 92 5345, RB 92 8064 e a variedade padrão CB 49-260 comportaram-se como variedades suscetíveis. A variedade RB 85 5156 comportou-se como de resistência intermediária e apenas as variedades RB 85 5453 e RB 85 5536 comportaram-se como tolerantes.Ratoon stunting disease (RSD caused by bacteria Leifsonia xyli subsp. xyli is one of the most economically important disease of sugarcane worldwide. The present survey had objective to evaluate the resistance of 10 RB commercial cultivars of sugarcane including CB 49-260 as a susceptible standard. The study evaluated the correlating the damages presented for overhauls productivity of inoculate and non inoculate parcels with the bacteria. The results showed that varieties RB 72 454, RB 83 5486, RB 86 7515, RB 92 8064, RB 92 5211, RB 92 5345 and RB 92 5268 were susceptible. RB 85 5156 had a intermediary resistance and varieties RB 85 5453 and RB 85 5536 both showed tolerant behavior.

  13. Causal reasoning in physics

    CERN Document Server

    Frisch, Mathias

    2014-01-01

    Much has been written on the role of causal notions and causal reasoning in the so-called 'special sciences' and in common sense. But does causal reasoning also play a role in physics? Mathias Frisch argues that, contrary to what influential philosophical arguments purport to show, the answer is yes. Time-asymmetric causal structures are as integral a part of the representational toolkit of physics as a theory's dynamical equations. Frisch develops his argument partly through a critique of anti-causal arguments and partly through a detailed examination of actual examples of causal notions in physics, including causal principles invoked in linear response theory and in representations of radiation phenomena. Offering a new perspective on the nature of scientific theories and causal reasoning, this book will be of interest to professional philosophers, graduate students, and anyone interested in the role of causal thinking in science.

  14. Estrutura e relações ambientais de grupos florísticos em fragmento de floresta estacional subtropical

    Directory of Open Access Journals (Sweden)

    Suzane Bevilacqua Marcuzzo

    2013-04-01

    Full Text Available Este estudo teve por objetivos analisar a estrutura de grupos florísticos na vegetação arbórea-arbustiva de um trecho de encosta de Floresta Estacional Subtropical, no Parque Estadual Quarta Colônia, RS, e determinar fatores ambientais importantes na ocorrência das espécies, a fim de subsidiar programas de restauração de áreas degradadas como ecossistema de referência. Para isso, foi realizado estudo fitossociológico em 12 parcelas de 200 m² (10 x 20 m, distantes 20 m entre si, distribuídas sistematicamente em quatro faixas de 100 m entre si, seguindo gradiente de topografia. Em cada parcela foram realizadas a identificação e a medição da circunferência à altura do peito (CAP e da altura total dos indivíduos arbóreos e arbustivos, ou seja, com CAP > 15 cm, denominado componente arbóreo. Os dados do sub-bosque foram obtidos em parcelas circulares com raio de 1,78 m, instaladas no centro das parcelas de 10 x 20 m, medindo-se indivíduos com altura > 30 cm e CAP <15 cm. As variáveis ambientais foram compostas pela declividade, pela intensidade luminosa, pelas características químicas e textura do solo. Os dados foram analisados segundo a estrutura e diversidade da vegetação por meio da análise de agrupamento pelo método TWINSPAN (Two-way Indicator Species Analysis e da ordenação pelo método CCA (Análise de Correspondência Canônica. Foi identificada a formação de dois grupos florísticos. A composição de espécies de cada grupo pertence a diferentes estágios de sucessão natural, conforme histórico de uso agrícola, e, segundo suas características funcionais, podem ser indicadas para programas de restauração florestal.

  15. Reação de cultivares de batata a Streptomyces scabies, agente causal da sarna comum profunda Reaction of potato cultivars to Streptomyces scabies, causal agent of deep common scab

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    Ivan Herman Fischer

    2009-09-01

    Full Text Available Este trabalho visou caracterizar quanto a critérios morfológicos e fisiológicos isolados de Streptomyces causadores de sarna comum profunda em batata; avaliar o comportamento de cultivares em relação à doença e a variação na agressividade entre os isolados da bactéria. Os isolados de Streptomyces apresentaram coloração cinza em meio extrato de levedura e malte e cadeias de esporos espiraladas, produzidas sobre um micélio aéreo. Ocorreu produção de melanina em meio de tirosina-ágar e a utilização de oito fontes de carbono recomendadas, propriedades estas que correspondem às descritas para S. scabies. Batatas-semente sadias de seis cultivares foram plantadas em substrato infestado com seis isolados de S. scabies separadamente e as plantas cultivadas em vasos e ambiente aberto. A severidade da doença foi estimada com auxílio de uma escala diagramática e avaliou-se o rendimento de tubérculos (g/planta. As cvs. Mondial e Jaete Bintje foram as mais resistentes à sarna comum com severidade média nos dois experimentos de 10,5% e 14,0%, respectivamente, seguidas por Asterix (17,4%, Ágata (21,8%, Monalisa (23,0% e Cupido (23,3%. A agressividade dos isolados variou quantitativamente, com severidade maior para o isolado M4 (34,7% e menor para o isolado M1 (6,2%. Redução da produção de tubérculos foi verificada na cv. Jaete Bintje, no primeiro experimento, e quando as cultivares foram infectadas pelos isolados A1, M2 e M3, no primeiro experimento, e pelo isolado M4, no segundo experimento.This work aimed to characterize the isolates of Streptomyces, responsible for deep common scab symptoms in potato, according to morphological and physiological criteria; to evaluate the resistance of potato cultivars to the disease and the aggressiveness of bacterium isolates. The Streptomyces isolates presented gray coloration on yeast extract and malt medium and spiral spore chains, produced on aerial hyphae. Production of melanina occurred

  16. Controle alternativo de Colletotrichum acutatum agente causal da queda prematura dos frutos cítricos Alternative control of Colletotrichum acutatum, causal agent of postbloom fruit drop of citrus

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    Katia Cristina Kupper

    2009-12-01

    Full Text Available A queda prematura dos frutos cítricos (QPFC, causada por Colletotrichum acutatum, dados os grandes prejuízos que têm causado aos produtores, constitui-se numa doença de grande importância econômica. O controle da doença é feito predominantemente mediante uso de fungicidas, que eleva o custo de produção e afeta negativamente o meio ambiente. Diante disso, este trabalho teve por objetivo buscar um método alternativo de controle da QPFC, mediante o uso de agentes de biocontrole ou de biofertilizantes. Diferentes concentrações de biofertilizantes (originários de duas fontes distintas e denominados de Bio1 e Bio 2; três isolados de Bacillus subtilis (ACB-69; 72 e 77 e três isolados de Trichoderma spp. (ACB-14; 37 e 39 foram testados, isoladamente ou em combinação, sob condições de laboratório, quanto à capacidade inibitória da germinação de conídios de C. acutatum. Estudaram-se, ainda, a produção de metabólitos termoestáveis por B. subtilis e o efeito sobre a germinação do patógeno. Quinze isolados de B. subtilis foram testados quanto à capacidade de prevenir a infecção por C. acutatum em flores destacadas de lima- ácida 'Tahiti' e, no campo, foram instalados dois experimentos, visando a testar ACBs e biofertilizantes no controle da doença. Verificou-se que o isolado ACB-72 (B. subtilis e ACB-37 (T. pseudokoningii foram os que mais inibiram a germinação do patógeno. Quanto à produção de metabólitos termoestáveis, ACB-69 e 77 foram os mais eficientes em produzir substâncias antifúngicas, e em quantidades suficientes para inibirem a germinação do patógeno. A mistura dos quatro isolados de Bacillus (ACBs: 69; 72; 77 e AP3 foi o que apresentou maior porcentagem de inibição (73%. Os biofertilizantes (Bio1 e Bio2, em concentrações acima de 10% e, quando em associação com isolados de Trichoderma spp., promoveram maiores inibições na germinação de C. acutatum. Em testes com flores destacadas

  17. Caracterização de isolados de Phytophthora drechsleri, agente causal da podridão mole de raízes de mandioca Characterization of Phytophthora drechsleri, the causal agent of cassava soft root rot

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    Maria de Fátima S. Muniz

    2006-04-01

    Full Text Available O presente trabalho teve como objetivo caracterizar nove isolados de Phytophthora sp. obtidos de mandioca (Manihot esculenta, através da morfologia e morfometria das estruturas propagativas e crescimento micelial em diferentes temperaturas e avaliar sua patogenicidade. Os esporângios produzidos em extrato de solo não esterilizado mostraram-se ovóides, não papilados, persistentes, formados em esporangióforos não ramificados ou em simpódio, com dimensões de 24,6 - 57,4 µ x 14,8 - 37,7 µm e relação comprimento/largura de 1,0 - 2,6. Os clamidósporos foram raros. Os oósporos obtidos em cultura monospórica em V8 ágar eram apleuróticos, com 13,1 - 34,4 µm de diâmetro. Oogônios mostraram-se esféricos e mediram 19,7 - 41,0 µm de diâmetro; anterídios anfígenos, com dimensões de 8,2 - 24,6 µm x 8,2 - 19,7 µm. O maior diâmetro das colônias ocorreu a 25 ºC em V8 ágar. Os isolados patogênicos às plantas e raízes destacadas de mandioca inoculados foram identificados como Phytophthora drechsleri.Nine Phytophthora isolates from cassava (Manihot esculenta were characterized based on morphology and morphometry of propagative structures, growth at 10, 15, 20, 25, 30 and 35 ºC, and by evaluating its pathogenicity. Sporangia produced on nonsterile soil extract were ovoid, nonpapillate and persistent, formed in a sympodium or unbranched sporangiophores, 24.6 to 57.4 µm long x 14.8 to 37.7 µm wide, and length-breadth ratio was 1.0 - 2.6. Chlamydospores were rarely observed. Oospores produced in single spore culture on V8 agar medium were aplerotic, and 13.1 to 34.4 µm in diameter. Antheridia were amphigynous, measuring 8.2 - 24.6 µ x 8.2 - 19.7 µ ; oogonia ranged from 19.7 to 41.0 µm in diameter. Culture growth was greatest at 25 ºC in V8 agar medium. The isolates that were pathogenic to plants and detached roots of cassava were identified as Phytophthora drechsleri Tucker.

  18. Regression to Causality

    DEFF Research Database (Denmark)

    Bordacconi, Mats Joe; Larsen, Martin Vinæs

    2014-01-01

    Humans are fundamentally primed for making causal attributions based on correlations. This implies that researchers must be careful to present their results in a manner that inhibits unwarranted causal attribution. In this paper, we present the results of an experiment that suggests regression...... models should note carefully both their models’ identifying assumptions and which causal attributions can safely be concluded from their analysis....

  19. The Equation of Causality

    OpenAIRE

    Chi, Do Minh

    1999-01-01

    We research the natural causality of the Universe. We find that the equation of causality provides very good results on physics. That is our first endeavour and success in describing a quantitative expression of the law of causality. Hence, our theoretical point suggests ideas to build other laws including the law of the Universe's evolution.

  20. Flor-Essence? Herbal Tonic Promotes Mammary Tumor Development in Sprague Dawley Rats

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, L; Montgomery, J; Steinberg, S; Kulp, K

    2004-01-28

    Background: Women who are diagnosed with breast cancer often self-administer complementary and alternative medicines to augment their conventional treatments, improve health, or prevent recurrence. Flor-Essence{reg_sign} Tonic is a complex mixture of herbal extracts used by cancer patients because of anecdotal evidence that it can treat or prevent disease. Methods: Female Sprague Dawley rats were given water or exposed to 3% or 6% Flor-Essence{reg_sign} beginning at one day of age. Mammary tumors were induced with a single oral 40 mg/kg/bw dose of dimethylbenz(a)anthracene at 50 days of age and sacrificed at 23 weeks. Rats were maintained on AIN-76A diet. Results: Control rats had palpable mammary tumor incidence of 51.0% at 19 weeks of age compared to 65.0% and 59.4% for the 3% and 6% Flor-Essence{reg_sign} groups respectively. Overall, no significant difference in time until first palpable tumor was detected among any of the groups. At necropsy, mammary tumor incidence was 82.5% for controls compared to 90.0% and 97.3% for rats consuming 3% and 6% Flor-Essence{reg_sign}, respectively. Mean mammary tumor multiplicity ({+-}SES) for the controls was 2.8 ({+-} 0.5) and statistically different from the 3% or 6% Flor- Essence{reg_sign} groups with 5.2 ({+-} 0.7), and 4.8 ({+-} 0.6), respectively (p{<=}0.01). As expected, the majority of isolated tumors were diagnosed as adenocarcinomas. Conclusions: Flor-Essence{reg_sign} can promote mammary tumor development in the Sprague Dawley rat model. This observation is contrary to widely available anecdotal evidence as well as the desire of the consumer that this commercially available herbal tonic will suppress and/or inhibit tumor growth.

  1. Physiological potential of cauliflower seeds Potencial fisiológico de sementes de couve-flor

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    Ana Lúcia Pereira Kikuti

    2008-01-01

    Full Text Available The assessment of seed physiological performance is essential to provide consistent information to compose quality control programs conducted by seed companies and allow prompt decisions to reduce post-harvest and commercialization problems. This research was carried to evaluate the efficiency of different procedures to determine cauliflower seed vigor. Six lots of the cultivar Sharon were initially characterized by germination and seedling emergence, and subsequently subjected to traditional and saturated salt accelerated aging, controlled deterioration, electrical conductivity, and potassium leachate tests, in two evaluation times. The traditional accelerated aging (41ºC/48 h, the saturated salt procedure (45ºC/72 h, the controlled deterioration (moisture content adjusted to 20% or 22% and aging at 45ºC/24 h, the electrical conductivity (50 seeds/75 mL water and evaluation after 4 h and the potassium leakage (25 seeds/50 mL of water and evaluation after 30 min laboratory tests are sensitive to detect differences in the physiological potential of cauliflower seeds. However, those results did not relate to the percentage seedling emergence in greenhouse controlled conditions, as a consequence of the favorable conditions for emergence. However, the differences identified in the tests may be related to the ability of seed lots to perform in less favorable environments.A eficiência da determinação do potencial fisiológico de lotes de sementes é essencial para a obtenção de informações consistentes, permitindo a composição de programas de controle de qualidade de sementes e a obtenção de informações consistentes para a redução de problemas pós-colheita e durante a comercialização. O objetivo desta pesquisa foi comparar a eficiência de diferentes procedimentos para a determinação do vigor de sementes de couve-flor. Para tanto, foram utilizados seis lotes do cultivar Sharon, caracterizados inicialmente pelos testes de germina

  2. Times and Causality

    OpenAIRE

    Davidson, Russell

    2013-01-01

    The understanding of causal chains and mechanisms is an essential part of any scientific activity that aims at better explanation of its subject matter, and better understanding of it. While any account of causality requires that a cause should precede its effect, accounts of causality inphysics are complicated by the fact that the role of time in current theoretical physics has evolved very substantially throughout the twentieth century. In this article, I review the status of time and causa...

  3. Variações estruturais e florísticas do carrasco no planalto da Ibiapaba, estado do Ceará Variations of structure and of flora of the "carrasco" vegetation of the Ibiapaba plateau, state of Ceará, Brazil

    OpenAIRE

    F. S. de ARAÚJO; F. R. MARTINS; SHEPHERD G. J.

    1999-01-01

    Carrasco é uma vegetação xerófila arbustiva densa alta, ainda pouco conhecida, que ocorre no domínio semi-árido do nordeste do Brasil, sobre Areias Quartzosas distróficas profundas, entre 700 e 900 m de altitude, no planalto da Ibiapaba e chapada do Araripe. Este trabalho tem por objetivo conhecer a estrutura e a composição da comunidade lenhosa e possíveis relações dessas variações espaciais com variáveis pedológicas. Em Jaburuna (3°54'34"S, 40°59'24"W, cerca de 830 m de altitude), município...

  4. Causality in Europeanization Research

    DEFF Research Database (Denmark)

    Lynggaard, Kennet

    2012-01-01

    Discourse analysis as a methodology is perhaps not readily associated with substantive causality claims. At the same time the study of discourses is very much the study of conceptions of causal relations among a set, or sets, of agents. Within Europeanization research we have seen endeavours to......, it suggests that discourse analysis and the study of causality are by no means opposites. The study of Europeanization discourses may even be seen as an essential step in the move towards claims of causality in Europeanization research. This chapter deals with the question of how we may move from the...

  5. Diferenças florísticas e estruturais entre fitofisionomias do cerrado em Assis, SP, Brasil

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    Eduardo da Silva Pinheiro

    2012-02-01

    Full Text Available A classificação das fitofisionomias tem-se constituído em desafio entre os pesquisadores da vegetação de cerrado, seja por não haver critérios florísticos ou quantitativos claros para sua separação, seja pelas alterações que sofrem ao longo do tempo. O objetivo deste estudo foi caracterizar três tipos fitofisionômicos de cerrado na Estação Ecológica de Assis, bem como verificar se são florística e, ou, estruturalmente distintos, buscando-se as melhores variáveis para caracterizá-los. A área amostral compreendeu 30 parcelas permanentes de 20 x 50 m, sendo 10 parcelas para cada um dos tipos fisionômicos: cerrado típico, cerrado denso e cerradão, em que foram identificadas e medidas as árvores com diâmetro à altura do peito > 5 cm. As três fitofisionomias de cerradoestudadas mostraram-se estruturalmente distintas em classes de área basal, cobertura de copas e altura das maiores árvores. O melhor descritor para classificar as fitofisionomias, por ser facilmente mensurável e pouco variável com o critério de inclusão, é a área basal (m² ha-1. Floristicamente, as fitofisionomias savânicas (cerradotípico e cerrado denso não se diferenciam, quer seja analisando apenas a presença e ausência das espécies, quer seja analisando a importância relativa das espécies na comunidade (fitossociologia. Em síntese, há três fitofisionomias distintas, mas a flora se diferencia apenas entre o cerradão e as fitofisionomias savânicas. A análise das espécies exclusivas de cada fitofisionomia quanto à tolerância à sombra, com base na literatura, indicou que a baixa disponibilidade de luz sob as copas no cerradão pode ter sido o fator condicionante da diferenciação entre esta e as demais fitofisionomias do cerrado lato sensu.

  6. Caracterização dos taninos condensados das espécies maniçoba (Manihot pseudoglazovii, flor-de-seda (Calotropis procera, feijão-bravo (Capparis flexuosa, L e jureminha (Desmanthus virgatus Characterization of condensed tannin of the species maniçoba (Manihot pseudoglaziovii, flor-de-seda (Calotropis procera, feijão-bravo (Capparis flexuosa and jureminha (Desmanthus virgatus

    Directory of Open Access Journals (Sweden)

    S.E.S.B.S. Cruz

    2007-08-01

    Full Text Available Caracterizaram-se os taninos condensados (TC e determinaram-se a composição bromatológica e a digestibilidade in vitro da matéria seca (DIVMS das espécies maniçoba (Manihot pseudoglazovii Pax & Hoffman, flor-de-seda (Calotropis procera, feijão-bravo (Capparis flexuosa, L e jureminha (Desmanthus virgatus (L. Willd. As concentrações em tanino solúvel, tanino ligado ao resíduo e tanino total (TT das espécies foram determinadas pelo método butanol-HCL e a adstringência pelo método de difusão radial. Para a DIVMS, foi utilizado método de dois estágios. Foram observadas diferenças entre as espécies (PCondensed tannins (CT of the species maniçoba (Manihot pseudoglaziovii, flor-de-seda (Calotropis procera, feijão-bravo (Capparis flexuosa and jureminha (Desmanthus virgatus were characterized and the chemical composition and in vitro dry matter digestibility (IVDMD of those species were determined. Concentration of soluble tannin (ST, bound tannin (BT and total tannin (TT of the plants was determined using butanol-HCL method; astringency was determined, using radial diffusion method, and the IVDMD was determined using two-stages method. Concentration and astringency of condensed tannins varied between species (P<0.01. Jureminha was the species that presented the highest value (2.4% TT and 13.7-3 astringency. No tannins were detected in flor-de-seda. Crude protein was higher than 16% in all studied species, and the ADF and lignin values were lower than 39 and 15%, respectively. The IVDMD was low in jureminha (43% and high in flor-de-seda (80%. The correlation between IVDMD and TT was low (r²=0.097.

  7. Composição Florística do estrato arbóreo da Floresta Estacional Semidecidual na Planície Aluvial do rio Doce, Linhares, ES, Brasil Floristic composition of the tree layer in Atlantic forest on the rio Doce alluvial floodplain, Espírito Santo State, Brazil

    Directory of Open Access Journals (Sweden)

    Samir Gonçalves Rolim

    2006-09-01

    Full Text Available Este trabalho apresenta a flora de espécies arbóreas e palmeiras na floresta estacional semidecidual na planície aluvial do rio Doce, uma área de cerca de 20.000 ha, a partir de Linhares (ES até próximo à foz no oceano atlântico. Foram determinadas 408 espécies (27 classificadas em gênero e 59 famílias, entre arbóreas e palmeiras. Por meio da análise de agrupamento, foi evidenciado que a floresta do rio Doce é muito semelhante floristicamente à floresta estacional dos tabuleiros terciários, que estas se agrupam com as florestas estacionais do rio Doce em MG e que, por sua vez, todas estas se agrupam com as florestas ombrófilas do sul da Bahia, sendo o conjunto nitidamente separado das outras formações ombrófilas costeiras. Foram encontradas dezenas de espécies deocorrência restrita ou pouco frequentes em levantamentos na floresta atlântica, enfatizando a importância da área para conservação da biodiversidade. Pelo fato das matas de cacau na região abrangerem mais de 80% dessa área, sugere-se a delimitação de uma Área de Proteção Ambiental, que permita conciliar o cultivo do cacau com a proteção da biodiversidade.The tree and palm flora was studied in the Atlantic forest of the rio Doce alluvial floodplain, in a 20,000ha area, between Linhares (Espírito Santo State and the Atlantic Ocean. The floristic survey recorded 408 species and 59 families. Floristic composition was compared to other forests of São Paulo, Minas Gerais, Bahia and Rio de Janeiro states using cluster analysis. The forest flora of the study area was most similar to that of forests in Espírito Santo, Minas Gerais, and Bahia. Dozens of species in the study area are restricted and rare in Atlantic forest; this area deserves special attention for biodiversity conservation. The Brazilian government should pay heed to the biological importance of this area and declare it an Environmental Protection Area, a type of conservation unit where

  8. Efeito inibitório de extratos vegetais sobre Colletotrichum gloeosporioides - agente causal da podridão de frutos de mamoeiro

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    Ribeiro Luiz Fernando

    1999-01-01

    Full Text Available Extratos aquosos foram obtidos a partir de bulbilhos de alho, folhas de hortelã e mamona e frutos de pimenta. Após a incorporação destes extratos em BDA, obtendo-se concentrações de 100, 200, 500, 1000, 5000 e 10000 ppm, foi avaliado o crescimento e a produção de conídios de um isolado de Colletotrichum gloeosporioides, agente de podridão em frutos de mamoeiro. Os resultados demonstraram o efeito inibitório dos diferentes extratos a partir da concentração de 200 ppm. O extrato de alho inibiu o crescimento micelial, em porcentagens variáveis de 5,3 a 67,6%, porém não atuou de modo expressivo sobre a produção de conídios. Em contraposição, os extratos de hortelã, mamona e pimenta promoveram inibição menos acentuada do crescimento de micélio, porém reduziram drasticamente a produção de conídios em níveis variáveis de 41 a 84%, de acordo com as concentrações crescentes dos mesmos. As propriedades fungitóxicas detectadas nos extratos utilizados no ensaio evidenciaram o uso potencial dos mesmos como alternativa aos métodos físicos e químicos convencionalmente usados para o controle da doença.

  9. Composição florística das formações vegetais sobre uma turfeira topotrófica da planície costeira do Rio Grande do Sul, Brasil Floristic composition of the vegetation types of a fen on the southern Brazil coastal plain in Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    César S. B. Costa

    2003-06-01

    Full Text Available Turfeiras topotróficas caracterizam-se como corpos de águas rasas, permanente ou periodicamente alagados por água do lençol freático, percolada através do solo inorgânico das terras altas adjacentes à depressão central da turfeira. Possuem solos orgânicos e a cobertura vegetal é dominanda por fanerógamas aquáticas emergentes. Este estudo visou o levantamento da diversidade específica e caracterização das principais formações vegetais ao longo de duas transecções de 200m em uma turfeira topotrófica na localidade de Domingos Petrolini (Rio Grande, RS. Em março/1998, o total de 48 espécies vegetais (30 famílias foram encontradas nas 40 parcelas de 5m × 2m observadas nas duas transecções efetuadas. Cerca de 56% das espécies eram plantas aquáticas herbáceas (submersas, flutuantes ou emergentes e apenas 10% arbustos ou árvores. Sete espécies dominaram a cobertura vegetal (Eupatorium tremulum, Eryngium pandanifolium, Blechnum brasiliense, Rhynchospora sp., Xyris jupicai, Utricularia gibba e Cladium jamaicense. Quatro formações vegetais tipicamente distribuídas em relação à topografia e à distância do lençol freático foram caracterizadas: (1 banhados do capim-navalha Cladium jamaicense, drenados apenas no verão, ocupam a depressão central da turfeira (DCT; (2 planos médios de Gravatás/Caraguatás (Eryngium pandanifolium associados a samambaia Blechnum brasiliense (+0,5 a +1,5m da DCT; (3 bosques marginais de arbustos palustres (+1 a +3m da DCT são dominados por Eupatorium tremulum; e (4 campos de turfa recobertos por ciperáceas de pequeno porte, gramas boiadeiras e botões-de-ouro (Xyris jupicai ocupam a borda do afloramento da turfa (+3 a +4m da DCT.Fens are characterized as shallow water bodies permanently or periodically flooded by ground-water table, originating from the percolation of rain water through mineral soils of uplands adjacent to the fen central basin. Fens have organic soil and their plant

  10. Influência da cobertura e do solo na composição florística do sub-bosque em uma floresta estacional semidecidual em Viçosa, MG, Brasil Cover and soil influence at understory of a Seasonal Tropical Forest, Minas Gerais State, Brazil

    Directory of Open Access Journals (Sweden)

    João Augusto Alves Meira-Neto

    2005-09-01

    Full Text Available A relação ecológica planta-luz tem sido estudada desde o início do século XX. As análises da relação da luminosidade ao nível das comunidades florestais têm se valido de medições indiretas por meio de índices de cobertura, mas sem a aplicação da fotogrametria para estimar essa cobertura. Este trabalho foi idealizado para utilizar fotogrametria do dossel, tornando-a aplicável ao estudo da luminosidade no sub-bosque herbáceo-arbustivo. Teve como objetivos estabelecer a relação existente entre espécies do estrato herbáceo-arbustivo e a cobertura do dossel e averiguar a existência de correlações entre espécies, luminosidade e variáveis pedológicas. Para tanto, foram tiradas fotografias em preto e branco nos períodos seco e chuvoso, em 100 (1 m×1 m parcelas aplicadas para a amostragem da vegetação herbácea. Foram colhidas amostras de solo em cada parcela. A partir dos valores médios das medidas de cobertura estimada pelas fotografias dos períodos seco e chuvoso calculou-se o valor médio de cobertura para cada espécie amostrada. Por meio do teste "t" student e da Análise de Correspondência Canônica foram determinadas as relações entre as espécies, a luminosidade e as variáveis pedológicas no estrato herbáceo-arbustivo. A cobertura não foi significativamente diferente nas épocas seca e na chuvosa. Apenas três espécies, Heisteria silviani, Calathea brasiliensis e Psychotria conjugens, tiveram médias de cobertura significativamente maiores que a média amostral e outras três, Olyra micrantha, Lacistema pubescens e Pteris denticulata, tiveram médias menores. As distribuições de parcelas pelos valores de cobertura, de tamanho de clareiras e pelo número de clareiras mostraram-se similares às distribuições encontradas na literatura para outras florestas tropicais e, portanto, o método da fotogrametria revelou-se adequado para a avaliação da cobertura. Verificou-se que os teores de cálcio, magn

  11. Viscous causal cosmologies

    International Nuclear Information System (INIS)

    A set of spatially homogeneous and isotropic cosmological geometries generated by a class of non-perfect is investigated fluids. The irreversibility if this system is studied in the context of causal thermodynamics which provides a useful mechanism to conform to the non-violation of the causal principle. (author)

  12. Causality in Classical Electrodynamics

    Science.gov (United States)

    Savage, Craig

    2012-01-01

    Causality in electrodynamics is a subject of some confusion, especially regarding the application of Faraday's law and the Ampere-Maxwell law. This has led to the suggestion that we should not teach students that electric and magnetic fields can cause each other, but rather focus on charges and currents as the causal agents. In this paper I argue…

  13. Causality in demand

    DEFF Research Database (Denmark)

    Nielsen, Max; Jensen, Frank; Setälä, Jari;

    2011-01-01

    to fish demand. On the German market for farmed trout and substitutes, it is found that supply sources, i.e. aquaculture and fishery, are not the only determinant of causality. Storing, tightness of management and aggregation level of integrated markets might also be important. The methodological......This article focuses on causality in demand. A methodology where causality is imposed and tested within an empirical co-integrated demand model, not prespecified, is suggested. The methodology allows different causality of different products within the same demand system. The methodology is applied...... implication is that more explicit focus on causality in demand analyses provides improved information. The results suggest that frozen trout forms part of a large European whitefish market, where prices of fresh trout are formed on a relatively separate market. Redfish is a substitute on both markets. The...

  14. Causality and Composite Structure

    CERN Document Server

    Joglekar, Satish D

    2007-01-01

    We study the question of whether a composite structure of elementary particles, with a length scale $1/\\Lambda$, can leave observable effects of non-locality and causality violation at higher energies (but $\\lesssim \\Lambda$). We formulate a model-independent approach based on Bogoliubov-Shirkov formulation of causality. We analyze the relation between the fundamental theory (of finer constituents) and the derived theory (of composite particles). We assume that the fundamental theory is causal and formulate a condition which must be fulfilled for the derived theory to be causal. We analyze the condition and exhibit possibilities which fulfil and which violate the condition. We make comments on how causality violating amplitudes can arise.

  15. Agency, time and causality

    Directory of Open Access Journals (Sweden)

    Thomas eWidlok

    2014-11-01

    Full Text Available Cognitive Scientists interested in causal cognition increasingly search for evidence from non-WEIRD people but find only very few cross-cultural studies that specifically target causal cognition. This article suggests how information about causality can be retrieved from ethnographic monographs, specifically from ethnographies that discuss agency and concepts of time. Many apparent cultural differences with regard to causal cognition dissolve when cultural extensions of agency and personhood to non-humans are taken into account. At the same time considerable variability remains when we include notions of time, linearity and sequence. The article focuses on ethnographic case studies from Africa but provides a more general perspective on the role of ethnography in research on the diversity and universality of causal cognition.

  16. Composição lignocelulósica e isótopica da vegetação e da matéria orgânica do solo de uma turfeira tropical: I - composição florística, fitomassa e acúmulo de carbono Lignocellulosic and isotopic composition of vegetation and soil organic matter of a tropical peat: I floristic composition, biomass and carbon stock

    Directory of Open Access Journals (Sweden)

    Vinicius Evangelista Silva

    2013-02-01

    Full Text Available A matéria orgânica do solo (MOS é um dos grandes reservatórios de carbono (C da Terra e constitui um dos principais componentes do ciclo do C. Turfeiras, ambientes acumuladores de MOS, são produto da decomposição de vegetais, que se desenvolvem e se acumulam em ambientes saturados com água, sendo o estádio inicial da sequência de carbonificação. A fitomassa participa de forma marcante no ciclo global do C, armazenando em torno de 85 % de todo o C terrestre acima do solo. O tecido vegetal é composto principalmente por lignina, celulose e hemicelulose, constituindo até 85 % da biomassa seca. As plantas discriminam C de forma diferenciada, em razão de seu ciclo fotossintético (C3, C4 e CAM. As turfeiras da Serra do Espinhaço Meridional (SdEM-MG são colonizadas por vegetação de Campo Limpo Úmido (CLU e de Floresta Estacional Semidecidual (FES, onde ocorrem espécies dos ciclos fotossintéticos C3 e C4. Este trabalho objetivou avaliar a contribuição dessas duas fitofisionomias para o acúmulo de MOS, por meio da avaliação da fitomassa e da composição lignocelulósica e isotópica da vegetação e da MOS. A turfeira estudada localiza-se na SdEM e ocupa 81,75 ha. Para a estimativa da fitomassa do CLU e da FES, foram marcadas três parcelas de 0,5 x 0,5 m em cada fitofisionomia, onde todos os indivíduos da parcela foram cortados e armazenados. Para as análises isotópicas e lignocelulósicas da vegetação, identificaram-se as espécies dominantes em cada fitofisionomia. Amostras de solo foram coletadas em três locais representativos sob cada fitofisionomia, a cada 5 cm de profundidade, até 50 cm. Foram extraídas a celulose e a lignina das folhas das 15 espécies dominantes e das 60 amostras de turfeira para quantificação e determinação dos valores de δ13C e δ15N. Para datação da MOS, o 14C foi determinado em três profundidades, sob o CLU e a FES. A produção da fitomassa da FES foi muito superior à produ

  17. Análise da florística e estrutura de floresta primária visando a seleção de espécies-chave, através de análise multivariada, para a restauração de áreas mineradas em unidades de conservação

    Directory of Open Access Journals (Sweden)

    Rafael Paiva Salomão

    2012-12-01

    Full Text Available Na Amazônia, vários empreendimentos minerários estão situados em unidades de conservação. A restauração ecológica após a lavra do minério abrange vários atributos. Entre esses, destaca-se a necessidade de o ecossistema restaurado conter um conjunto de espécies-chave de ocorrência no ecossistema de referência e, dessa forma, proporcionar estrutura apropriada de comunidade, além de ser constituído do maior número possível de espécies nativas. Objetivou-se, neste trabalho, analisar um índice fitossociológico e socioeconômico (IFSE, obtido por técnicas de análise multivariada. O modelo envolveu seis variáveis quantitativas (abundância, frequência, dominância, biomassa, valor comercial da madeira e quantidade de produtos florestais não madeireiros e igual número de variáveis qualitativas. Em uma área de floresta ombrófila de 1.321 ha, foram amostradas 315 parcelas de 0,25 ha, em que todos os indivíduos com DAP > 10 cm foram identificados e mensurados. Foram registrados 36.298 indivíduos, distribuídos em 898 espécies, abrangendo 62 famílias. As espécies foram ranqueadas através do índice proposto em três categorias de prioridade fitossociológica e socioeconômica (alta, média e baixa. A adequação da análise fatorial foi determinada pelos testes de Bartlett e KMO. O teste de Bartlett avaliou a significância geral da matriz de correlação a 1% de probabilidade. O teste KMO indicou que as variáveis estão correlacionadas, e o modelo fatorial apresentou nível muito bom de adequação aos dados. O uso de análise multivariada foi estatisticamente validado para o emprego do IFSE. Entre as 898 espécies analisadas, 25 foram selecionadas como prioritárias (categorias alta e média, sendo reconhecidas como espécies-chave. Foi estimada a densidade de plantio dessas espécies para recuperação de áreas mineradas na Amazônia, com condições biológicas e ambientais semelhantes às relatadas neste estudo. A

  18. Phytophthora palmivora, agente da podridão de raiz e frutos de mamoeiro no Estado de Alagoas Phytophthora palmivora, causal agent of root and fruit rots of papaya in the State of Alagoas, Brazil

    Directory of Open Access Journals (Sweden)

    Juliana Paiva Carnaúba

    2006-04-01

    Full Text Available O mamoeiro (Carica papaya é uma das mais importantes fruteiras tropicais, e seus frutos contribuem com uma produção de 1,65 milhão de toneladas por ano para o Brasil. Um isolado de Phytophthora sp. obtido de frutos de mamoeiro da cultivar Havaí, em Alagoas, foi caracterizado morfologicamente e sua patogenicidade foi confirmada em frutos e mudas deste hospedeiro. Em meio suco V-8, os esporangióforos apresentaram-se delgados, simples ou pouco ramificados, enquanto os esporângios se apresentaram ovóides a elipsóides, proeminentemente papilados e um pedicelo curto na porção basal, medindo em média 37,68 x 27,52 mm. Através das características apresentadas pelo isolado e os sintomas induzidos, o agente causal foi identificado como Phytophthora palmivora. Apesar de essa doença já ocorrer em outros estados, como Bahia, Espírito Santo, São Paulo, Pernambuco e Pará, este é o primeiro relato de Phytophthora palmivora em mamoeiro no Estado de Alagoas.The papaya (Carica papaya is one of the most important tropical fruit crops and its fruit contribute with a production of 1.65 millions tons/year in Brazil. An isolated of Phytophthora sp. gotten from papaya fruits cv. Hawaii, in the state of Alagoas, was characterized morphologically and its pathogenicity to this fruits and seedling was confirmed. In a V-8 medium, the sporangiophores presented to be slim, simple or little ramified, while the sporangia presented ovoid to ellipsoid, prominently papillae and one short pedicel in the basal portion, measuring in average 37,68 x 27,52 (m. Through the characteristics presented by the isolated and the induced symptoms, the causal agent was identified as Phytophthora palmivora. Despite of this disease already occurring in other states like in Bahia, Espirito Santo, São Paulo, Pernambuco and Pará, this is the first report of Phytophthora palmivora on papaya in the state of Alagoas, Brazil.

  19. Couve-flor cultivada em substrato: marcha de absorção de macronutrientes e micronutrientes Cauliflower cultivated in substrate: progress of absorption of macro and micronutrients

    Directory of Open Access Journals (Sweden)

    Adriana Ursulino Alves

    2011-02-01

    Full Text Available Com o objetivo de avaliar marcha de absorção de macro e micronutrientes na couve-flor cultivada em substrato, um experimento foi conduzido em casa de vegetação da UNESP, Campus de Jaboticabal, SP. O delineamento experimental foi de blocos ao acaso, com seis tratamentos e cinco repetições. Os tratamentos foram constituídos pelas épocas de amostragem (20; 30; 40; 50; 60 e 70 dias após o transplante. Avaliaram-se os teores e acúmulo dos macro e micronutrientes da parte aérea e raiz. A maior demanda de nutriente aconteceu no período de 60 a 70 (DAT para macro e micronutrientes. A ordem decrescente dos macronutrientes acumulados pela couve-flor foi: K, N, S, P, Mg e Ca e os micro foi: Fe, Zn, B, Mn e Cu.With the objective of evaluating the progress of absorption of macro and micronutrients in cauliflower cultivated in substrate, an experiment was conducted in a greenhouse at the Universidade do Estado de São Paulo, in Jaboticabal, Brazil. The experimental desing used was randomized blocks, with six treatments and five replicates. The treatments comprised times of sampling (20; 30; 40; 50; 60 and 70 days after the transplant. The composition and accumulation of the macro and micronutrients of the shoot and root were evaluated. The biggest demand of nutrient happened in the period of 60 to 70 (DAT for macro and micronutrients. The decreasing order of the macronutrients accumulated by the cauliflower was K, N, S, P, Mg and Ca and for micronutrients Fe, Zn, B, Mn and Cu.

  20. Análise florística e estrutural de sistemas silviagrícolas em Tomé-Açu, Pará

    Directory of Open Access Journals (Sweden)

    Édson Luis Bolfe

    2011-10-01

    Full Text Available O objetivo deste trabalho foi analisar a composição florística e estrutural de sistemas silviagrícolas em Tomé-Açu, Pará. Os dados dendrométricos foram obtidos por inventário em 40 parcelas amostrais, com três unidades cada uma, no total de 120 unidades de 10x10 m. Foi inventariada a média de 1.424,3 indivíduos por hectare, pertencentes a 27 famílias e a 54 espécies. Tendo-se considerado a variabilidade dos estágios vegetativos, os diferentes sistemas silviagrícolas (SAF foram divididos em quatro classes hierárquicas: SAF 1, SAF 2, SAF 3, e SAF 4, para estabelecer um sistema de classificação passível de ser utilizado em outras avaliações de campo e em classificações digitais por meio do sensoriamento remoto. Espécies observadas em outros sistemas da região amazônica também foram relevantes para este estudo, especialmente Theobroma cacao, T. grandiflorum e Euterpe oleracea que, juntas, apresentaram médias de frequência relativa de 51%, densidade relativa de 69,2%, dominância relativa de 50,1% e índice de valor de importância de 56,8%. Os dados médios de diversidade florística, abundância, área basal e valor de importância indicam os sistemas silviagrícolas da região de Tomé-Açu como sistemas de produção com potencial econômico e ambiental, se adotado manejo adequado e racional.

  1. Dynamics and causality constraints

    International Nuclear Information System (INIS)

    The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)

  2. Dynamics and causality constraints

    CERN Document Server

    De Souza, M M

    2000-01-01

    The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Local causality are kinematical constraints dynamically implemented via solutions of the field equations, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away and implies on deep implications to the nature of physical interactions.

  3. Quantum Causal Graph Dynamics

    CERN Document Server

    Arrighi, Pablo

    2016-01-01

    Consider a graph having quantum systems lying at each node. Suppose that the whole thing evolves in discrete time steps, according to a global, unitary causal operator. By causal we mean that information can only propagate at a bounded speed, with respect to the distance given by the graph. Suppose, moreover, that the graph itself is subject to the evolution, and may be driven to be in a quantum superposition of graphs---in accordance to the superposition principle. We show that these unitary causal operators must decompose as a finite-depth circuit of local unitary gates. This unifies a result on Quantum Cellular Automata with another on Reversible Causal Graph Dynamics. Along the way we formalize a notion of causality which is valid in the context of quantum superpositions of time-varying graphs, and has a number of good properties. Keywords: Quantum Lattice Gas Automata, Block-representation, Curtis-Hedlund-Lyndon, No-signalling, Localizability, Quantum Gravity, Quantum Graphity, Causal Dynamical Triangula...

  4. Causal Inference and Causal Explanation with Background Knowledge

    OpenAIRE

    Meek, Christopher

    2013-01-01

    This paper presents correct algorithms for answering the following two questions; (i) Does there exist a causal explanation consistent with a set of background knowledge which explains all of the observed independence facts in a sample? (ii) Given that there is such a causal explanation what are the causal relationships common to every such causal explanation?

  5. L-Histidine inhibits biofilm formation and FLO11- associated phenotypes in Saccharomyces cerevisiae flor yeasts

    OpenAIRE

    Bou Zeidan, Marc; Zara, Giacomo; Viti, Carlo; Decorosi, Francesca; Mannazzu, Ilaria Maria; Budroni, Marilena; Giovannetti, Luciana; Zara, Severino

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of FLO11 which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling FLO11 alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce FLO11p. The flor strains generally metabolized amino acids and dipeptides a...

  6. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    Science.gov (United States)

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-01-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis – based on cellular components and biological process GO terms – was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in “Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation” [1]. PMID:27104213

  7. The chemistry and biological activity of herbs used in Flor-Essence herbal tonic and Essiac.

    Science.gov (United States)

    Tamayo, C; Richardson, M A; Diamond, S; Skoda, I

    2000-02-01

    The herbal mixtures, Essiac and Flor-Essence, are sold as nutritional supplements and used by patients to treat chronic conditions, particularly cancer. Evidence of anticancer activity for the herbal teas is limited to anecdotal reports recorded for some 40 years in Canada. Individual case reports suggest that the tea improves quality of life, alleviates pain, and in some cases, impacts cancer progression among cancer patients. Experimental studies with individual herbs have shown evidence of biological activity including antioxidant, antioestrogenic, immunostimulant, antitumour, and antiocholeretic actions. However, research that demonstrates these positive effects in the experimental setting has not been translated to the clinical arena. Currently, no clinical studies of Essiac or Flor-essence are published, but a clinical study is being planned at the British Columbia Cancer Agency by the University of Texas-Center for Alternative Medicine (UT-CAM) and Tzu-Chi Institute for Complementary and Alternative Medicine. PMID:10641040

  8. Causality and the Doppler Peaks

    OpenAIRE

    Turok, Neil

    1996-01-01

    Could cosmic structure have formed by the action of causal physics within the standard hot big bang, or was a prior period of inflation required? Recently there has been some discussion of whether causal sources could reproduce the pattern of Doppler peaks of the standard scale-invariant adiabatic theory. This paper gives a rigorous definition of causality, and a causal decomposition of a general source. I present an example of a simple causal source which mimics the standard adiabatic theory...

  9. Dynamics of Causal Sets

    CERN Document Server

    Rideout, D

    2002-01-01

    The Causal Set approach to quantum gravity asserts that spacetime, at its smallest length scale, has a discrete structure. This discrete structure takes the form of a locally finite order relation, where the order, corresponding with the macroscopic notion of spacetime causality, is taken to be a fundamental aspect of nature. After an introduction to the Causal Set approach, this thesis considers a simple toy dynamics for causal sets. Numerical simulations of the model provide evidence for the existence of a continuum limit. While studying this toy dynamics, a picture arises of how the dynamics can be generalized in such a way that the theory could hope to produce more physically realistic causal sets. By thinking in terms of a stochastic growth process, and positing some fundamental principles, we are led almost uniquely to a family of dynamical laws (stochastic processes) parameterized by a countable sequence of coupling constants. This result is quite promising in that we now know how to speak of dynamics ...

  10. Dynamics Of Causal Sets

    CERN Document Server

    Rideout, D P

    2001-01-01

    The Causal Set approach to quantum gravity asserts that spacetime, at its smallest length scale, has a discrete structure. This discrete structure takes the form of a locally finite order relation, where the order, corresponding with the macroscopic notion of spacetime causality, is taken to be a fundamental aspect of nature. After an introduction to the Causal Set approach, this thesis considers a simple toy dynamics for causal sets. Numerical simulations of the model provide evidence for the existence of a continuum limit. While studying this toy dynamics, a picture arises of how the dynamics can be generalized in such a way that the theory could hope to produce more physically realistic causal sets. By thinking in terms of a stochastic growth process, and positing some fundamental principles, we are led almost uniquely to a family of dynamical laws (stochastic processes) parameterized by a countable sequence of coupling constants. This result is quite promising in that we now know how to speak of dynamics ...

  11. Biased causal inseparable game

    CERN Document Server

    Bhattacharya, Some Sankar

    2015-01-01

    Here we study the \\emph{causal inseparable} game introduced in [\\href{http://www.nature.com/ncomms/journal/v3/n10/full/ncomms2076.html}{Nat. Commun. {\\bf3}, 1092 (2012)}], but it's biased version. Two separated parties, Alice and Bob, generate biased bits (say input bit) in their respective local laboratories. Bob generates another biased bit (say decision bit) which determines their goal: whether Alice has to guess Bob's bit or vice-verse. Under the assumption that events are ordered with respect to some global causal relation, we show that the success probability of this biased causal game is upper bounded, giving rise to \\emph{biased causal inequality} (BCI). In the \\emph{process matrix} formalism, which is locally in agreement with quantum physics but assume no global causal order, we show that there exist \\emph{inseparable} process matrices that violate the BCI for arbitrary bias in the decision bit. In such scenario we also derive the maximal violation of the BCI under local operations involving tracele...

  12. Ensemble of Causal Trees

    International Nuclear Information System (INIS)

    We discuss the geometry of trees endowed with a causal structure using the conventional framework of equilibrium statistical mechanics. We show how this ensemble is related to popular growing network models. In particular we demonstrate that on a class of afine attachment kernels the two models are identical but they can differ substantially for other choice of weights. We show that causal trees exhibit condensation even for asymptotically linear kernels. We derive general formulae describing the degree distribution, the ancestor--descendant correlation and the probability that a randomly chosen node lives at a given geodesic distance from the root. It is shown that the Hausdorff dimension dH of the causal networks is generically infinite. (author)

  13. Ensemble of Causal Trees

    Science.gov (United States)

    Bialas, Piotr

    2003-10-01

    We discuss the geometry of trees endowed with a causal structure using the conventional framework of equilibrium statistical mechanics. We show how this ensemble is related to popular growing network models. In particular we demonstrate that on a class of afine attachment kernels the two models are identical but they can differ substantially for other choice of weights. We show that causal trees exhibit condensation even for asymptotically linear kernels. We derive general formulae describing the degree distribution, the ancestor--descendant correlation and the probability that a randomly chosen node lives at a given geodesic distance from the root. It is shown that the Hausdorff dimension dH of the causal networks is generically infinite.

  14. Causal graph dynamics

    CERN Document Server

    Arrighi, Pablo

    2012-01-01

    We generalize the theory of Cellular Automata to arbitrary, time-varying graphs. In other words we formalize, and prove theorems about, the intuitive idea of a labelled graph which evolves in time - but under the natural constraint that information can only ever be transmitted at a bounded speed, with respect to the distance given by the graph. The notion of translation-invariance is also generalized. The definition we provide for these `causal graph dynamics' is simple and axiomatic. The theorems we provide also show that it is robust. For instance, causal graph dynamics are stable under composition and under restriction to radius one. In the finite case some fundamental facts of Cellular Automata theory carry through: causal graph dynamics admit a characterization as continuous functions and they are stable under inversion. The provided examples suggest a wide range of applications of this mathematical object, from complex systems science to theoretical physics. Keywords: Dynamical networks, Boolean network...

  15. Causal inference in econometrics

    CERN Document Server

    Kreinovich, Vladik; Sriboonchitta, Songsak

    2016-01-01

    This book is devoted to the analysis of causal inference which is one of the most difficult tasks in data analysis: when two phenomena are observed to be related, it is often difficult to decide whether one of them causally influences the other one, or whether these two phenomena have a common cause. This analysis is the main focus of this volume. To get a good understanding of the causal inference, it is important to have models of economic phenomena which are as accurate as possible. Because of this need, this volume also contains papers that use non-traditional economic models, such as fuzzy models and models obtained by using neural networks and data mining techniques. It also contains papers that apply different econometric models to analyze real-life economic dependencies.

  16. Meat quality of lambs fed silk flower hay (Calotropis procera SW in the diet Qualidade de carne de cordeiros alimentados com feno de flor-de-seda (Calotropis procera SW na dieta

    Directory of Open Access Journals (Sweden)

    Roberto Germano Costa

    2011-06-01

    Full Text Available The objective of this work was to evaluate the influence of using silk flower hay replacing corn and soybean meal on physical-chemical and sensorial traits of lamb meat. It was used 32 intact Morada Nova male lambs (12.7 ± 2 kg initial body weigth on feedlot system, distributed in a completely randomized design with four levels (0, 15, 30 and 45% on dry matter basis. The use of silk flower hay in the diet influenced quality of meat and carcass, leg weight, tissue composition, moisture, juiciness and flavor. Replacing corn (26.67% and soybean (3.33% with silk flower hay does not affect the tissue composition, ratios and muscularity index of leg and physical-chemical parameters of semimembranosus muscle of Morada Nova lambs.Objetivou-se avaliar a influência do uso de feno de flor-de-seda em substituição ao milho e ao farelo de soja nas características físico-químicas e sensoriais da carne de cordeiros. Utilizaram-se 32 cordeiros Morada Nova, machos não-castrados (12,7 ± 2 kg de peso vivo inicial, em confinamento, distribuídos em delineamento inteiramente ao acaso com quatro níveis (0, 15, 30 e 45% com base na MS. A utilização de feno de flor-de-seda na dieta influenciou a qualidade da carcaça e da carne, o peso da perna, a composição tecidual, a umidade, a suculência e o sabor. A substituição do milho (26,67% e da soja (3,33% pelo feno de flor-de-seda não altera composição tecidual, relação e índice de muscularidade da perna e os parâmetros físico-químicos do músculo semimembranosus de cordeiros Morada Nova.

  17. A Causal Entropy Bound

    CERN Document Server

    Brustein, Ram

    2000-01-01

    The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic space-like region. This "causal entropy bound", scaling as the square root of EV, and thus lying around the geometric mean of Bekenstein's S/ER and holographic S/A bounds, is checked in various "critical" situations. In the case of limited gravity, Bekenstein's bound is the strongest while naive holography is the weakest. In the case of strong gravity, our bound and Bousso's holographic bound are stronger than Bekenstein's, while naive holography is too tight, and hence typically wrong.

  18. A Causal Entropy Bound

    OpenAIRE

    Brustein, R; Veneziano, G

    1999-01-01

    The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic space-like region. This "causal entropy bound", scaling as the square root of EV, and thus lying around the geometric mean of Bekenstein's S/ER and holographic S/A bounds, is checked in various "critical" situations. In the case of limited gravity, Bekenstein's bound is the strongest while naive holography is the weakest. In the case of strong gravity, our bound and Bousso...

  19. Caracterização molecular e patogênica de isolados de Xanthomonas albilineans (Ashby Dowson, agente causal da escaldadura das folhas da cana-de-açúcar Molecular and pathogenic characterization of isolates of Xanthomonas albilineans (Ashby Dowson, causal agent of sugarcane leaf scald

    Directory of Open Access Journals (Sweden)

    Mariana de Souza e Silva

    2007-12-01

    Full Text Available A escaldadura das folhas, causada pela bactéria Xanthomonas albilineans (Ashby Dowson, é uma das cinco doenças mais importantes da cana-de-açúcar e sua ocorrência reduz o rendimento e a longevidade da cultura. Variedades resistentes têm sido usadas para o controle, porém há evidências da ocorrência de variantes do patógeno. Em campos comerciais do Estado de São Paulo, tem sido observado que a mesma variedade de cana se apresenta como resistente em uma região e suscetível em outra, sugerindo a ocorrência de variantes na população do patógeno. Assim, o objetivo deste trabalho foi investigar a presença de diversidade genética da bactéria em áreas comerciais. Um total de 50 isolados foram obtidos em cultura pura a partir de plantas sintomáticas coletadas em Piracicaba (SP, Jaú (SP, região de Ribeirão Preto (SP e Iturama (MG. Os isolados foram confirmados como pertencentes à espécie X. albilineans por meio de características de colônias, serologia e PCR com 'primers' específicos. Para caracterização da diversidade genética, foi usado o método de Rep-PCR, a partir do DNA extraído de cada isolado. Oito isolados, provenientes dos diferentes grupos identificados por rep-PCR, foram usados em testes de patogenicidade, por meio de inoculação em duas variedades de cana. Os resultados confirmaram todos os isolados como pertencentes à espécie X. albilineans. Por meio de rep-PCR, foi demonstrada diversidade genética entre os isolados, os quais foram separados em três grupos: um grupo composto somente pelos isolados de Piracicaba; um segundo, contendo todos os isolados amostrados em Jaú e na região de Ribeirão Preto, e um isolado de Iturama; e, no terceiro, somente dois isolados coletados em Iturama. Os testes de patogenicidade revelaram diferenças na agressividade entre isolados, porém sem relação com sua região de origem. Este trabalho revelou a ocorrência de diversidade genética e de agressividade dentro da

  20. [Effect of Flor-Essence on serum levels of IL-6, IL-12, TNF-α and NK cells in exercise rats].

    Science.gov (United States)

    Lin, Hua; He, Ye-Heng; Xu, Rui; Zou, Wei

    2015-12-25

    The present study was aimed to investigate the effects of exercise and nutrition intervention on rat immune function. Flor-Essence is a kind of health food produced by FLORA company in Canada and certified by Quality Assurance International (QAI). Its main components are burdock root, cress leaves of grass, kelp, Turkish rhubarb root, et al. Flor-Essence has been shown to activate the body detoxification path, improve the physical environment, and inhibit cancer cell growth and proliferation. Sixty male Sprague-Dawley (SD) rats were randomly divided into six groups: control, NS + training, low-dose Flor-Essence + training, low-dose Flor-Essence, high-dose Flor-Essence + training, high-dose Flor-Essence groups. The rats in NS + training, low-dose Flor-Essence + training, high-dose Flor-Essence + training groups swam 35 min per day in the water tank for 6 days a week. One hour before exercise, the rats were given low- (2.5 mg/mL) or high-dose (5 mg/mL) Flor-Essence daily by intragastric administration, and the rats in NS + training group were given equivalent volume of NS. On the last day of four training weeks, all rats took part in a bout of exhaustive exercise, and then were sacrificed immediately. Arterial blood serum samples were taken for the assays of IL-6, IL-12 and TNF-α contents, spleens for natural killer (NK) cells activity. The results showed that serum IL-6 content in NS + training group was decreased compared with that in control group. Low- and high-dose Flor-Essence groups showed decreased IL-6, IL-12 and TNF-α serum contents, as well as longer exhaustive time, compared with control group. The improving effects of high-dose Flor- Essence on IL-6, TNF-α and exhaustive time were greater than those of low dose. Compared with NS + training, low- and high-dose Flor-Essence + training reduced serum contents of IL-6 and TNF-α, and prolonged exhaustive time; only high-dose Flor-Essence + training decreased serum IL-12 content and enhanced NK cells

  1. Causality and Free Will

    Czech Academy of Sciences Publication Activity Database

    Hvorecký, Juraj

    2012-01-01

    Roč. 19, Supp.2 (2012), s. 64-69. ISSN 1335-0668 R&D Projects: GA ČR(CZ) GAP401/12/0833 Institutional support: RVO:67985955 Keywords : conciousness * free will * determinism * causality Subject RIV: AA - Philosophy ; Religion

  2. Crescimento de girassol como flor em vaso em função de doses de paclobutrazol

    Directory of Open Access Journals (Sweden)

    Christina da Silva Wanderley

    2014-02-01

    Full Text Available O girassol (Helianthus annuus L., que é comumente cultivado para produção de sementes e óleo, também apresenta potencial de uso como planta ornamental. Entretanto, seu porte elevado dificulta essa utilização, principalmente como flor em vaso. Objetivou-se neste experimento avaliar os efeitos do regulador de crescimento paclobutrazol sobre o crescimento de plantas de girassol em vaso, cultivadas em sistema hidropônico, dentro de estufa, em vasos preenchidos com sílica moída. Os dois genótipos de girassol utilizados foram BRS Oásis, com capítulo marrom e altura média de 1,85 m, e Helio 358, com capítulo amarelo e altura média de 1,45 m. As doses de paclobutrazol avaliadas foram 0; 0,5; 1; 2; 4; e 6 mg L-1 , aplicadas diretamente no substrato de sílica moída. A solução nutritiva utilizada foi a de Hoagland, e as plantas foram mantidas sob aeração constante. O delineamento experimental foi o de blocos casualizados, em esquema fatorial com cinco repetições, totalizando 60 parcelas. Avaliaram-se a altura das plantas e a massa de matéria seca de raiz, caule, folhas e de capítulos. Houve efeito do paclobutrazol sobre o crescimento das plantas. O uso do paclobutrazol na dose de 2mgL-1 reduz a altura do girassol, porém não afeta a qualidade da inflorescência, o que pode viabilizar o seu uso na produção de flores de girassol como ornamentais. A sensibilidade ao paclobutrazol é maior para o genótipo Helio 358 em relação ao genótipo BRS Oásis.

  3. Essiac? and Flor-Essence? herbal tonics stimulate the in vitro growth of human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Kulp, K S; Montgomery, J L; McLimans, B; Latham, E R; Shattuck, D L; Klotz, D M; Bennett, L M

    2005-10-07

    People diagnosed with cancer often self-administer complementary and alternative medicines (CAMs) to supplement their conventional treatments, improve health, or prevent recurrence. Flor-Essence{reg_sign} and Essiac{reg_sign} Herbal Tonics are commercially available complex mixtures of herbal extracts sold as dietary supplements and used by cancer patients based on anecdotal evidence that they can treat or prevent disease. In this study, we evaluated Flor-Essence{reg_sign} and Essiac{reg_sign} for their effects on the growth of human tumor cells in culture. The effect of Flor-Essence{reg_sign} and Essiac{reg_sign} herbal tonics on cell proliferation was tested in MCF-7, MDA-MB-436, MDA-MB-231, and T47D cancer cells isolated from human breast tumors. Estrogen receptor (ER) dependent activation of a luciferase reporter construct was tested in MCF-7 cells. Specific binding to the ER was tested using an ICI 182,780 competition assay. Flor-Essence{reg_sign} and Essiac{reg_sign} herbal tonics at 1%, 2%, 4% and 8% stimulated cell proliferation relative to untreated controls and activated ER dependent luciferase activity in MCF-7 cells. A 10{sup -7} M concentration of ICI 870,780 inhibited the induction of ER dependent luciferase activity by Flor-Essence{reg_sign} and Essiac{reg_sign}, but did not affect cell proliferation. Flor-Essence{reg_sign} and Essiac{reg_sign} Herbal Tonics can stimulate the growth of human breast cancer cells through ER mediated as well as ER independent mechanisms of action. Cancer patients and health care providers can use this information to make informed decisions about the use of these CAMs.

  4. Tachyon Kinematics and causality

    International Nuclear Information System (INIS)

    The chronological order of the events along a space-like path is not invariant under Lorentz transformations, as wellknown. This led to an early conviction that tachyons would give rise to causal anomalies. A relativistic version of the Stuckelberg-Feynman switching procedure (SWP) has been invoked as the suitable tool to eliminate those anomalies. The application of the SWP does eliminate the motions backwards in time, but interchanges the roles of source and dector. This fact triggered the proposal of a host of causal paradoxes. Till now, however, it has not been recognized that such paradoxes can be sensibly discussed (and completely solved, at least in microphysics) only after having properly developed the tachyon relativistic mechanics. We start by showing how to apply the SWP, both in the case of ordiry Special Relativity, and in the case with tachyons. Then, we carefully exploit the kinematics of the tachyon-exchange between to (ordinary) bodies. Being finally able to tackle the tachyon-causality problem, we successively solve the paradoxes: (i) by Tolman-Regge; (ii) by Pirani; (iii) by Edmonds; (iv) by Bell. At last, we discuss a further, new paradox associated with the transmission of signals by modulated tachyon beams

  5. Causality between time series

    CERN Document Server

    Liang, X San

    2014-01-01

    Given two time series, can one tell, in a rigorous and quantitative way, the cause and effect between them? Based on a recently rigorized physical notion namely information flow, we arrive at a concise formula and give this challenging question, which is of wide concern in different disciplines, a positive answer. Here causality is measured by the time rate of change of information flowing from one series, say, X2, to another, X1. The measure is asymmetric between the two parties and, particularly, if the process underlying X1 does not depend on X2, then the resulting causality from X2 to X1 vanishes. The formula is tight in form, involving only the commonly used statistics, sample covariances. It has been validated with touchstone series purportedly generated with one-way causality. It has also been applied to the investigation of real world problems; an example presented here is the cause-effect relation between two climate modes, El Ni\\~no and Indian Ocean Dipole, which have been linked to the hazards in f...

  6. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    OpenAIRE

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-01-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis – based on cellular components and biological process GO terms – was performed for ...

  7. “Nunca nos fuimos. Frontera, Memoria y Resistencia en la Flor de Maig”

    OpenAIRE

    Mansilla, José

    2013-01-01

    El Ateneu Flor de Maig fue construido en Poblenou (Barcelona) hace más de cien años como sede de una de las mayores cooperativas de Catalunya. Desde su fundación hasta hoy día siempre ha estado ligado a la memoria del barrio, representando un símbolo de resistencia y cooperación para muchos de los vecinos del Poblenou. El pasado 2012 en el contexto de recortes que llevan a cabo las distintas administraciones públicas del Estado, el dinero municipal que proveía del pago del alquiler a los dueñ...

  8. Listado florístico de la Sierra de Santa Rosa, Guanajuato, México

    OpenAIRE

    Juan Martínez Cruz; Oswaldo Téllez-Valdés

    2004-01-01

    Actualmente la Sierra de Santa Rosa es una de las pocas áreas reminiscentes medianamente conservadas en Guanajuato, ya que desafortunadamente el estado se ha caracterizado por la degradación de su cubierta vegetal desde tiempos coloniales. En este estudio florístico se registran 21 taxa infraespecíficos, 496 especies, 273 géneros y 93 familias de plantas vasculares. De éstas, la familia Asteraceae tiene la mayor riqueza de especies, seguida por Poaceae y Lamiaceae. Se registraron tres especie...

  9. Número de anteras por flor, grãos de pólen por antera e capacidade germinativa do pólen de diferentes cultivares de macieiras

    Directory of Open Access Journals (Sweden)

    Celso Lopes de Albuquerque Junior

    2010-12-01

    Full Text Available O objetivo deste trabalho foi avaliar o número de anteras por flor, grãos de pólen por antera e capacidade germinativa do pólen de diferentes cultivares de macieiras. O trabalho foi executado no Laboratório de Fisiologia do Desenvolvimento e Genética Vegetal da Universidade Federal de Santa Catarina, e as coletas a campo foram realizadas na Epagri/Estação Experimental de Caçador-SC, em outubro de 2005. Foram utilizadas as seguintes cultivares comerciais de macieira desenvolvidas no Brasil: Primícia, Princesa, Fred Hough, Catarina, Baronesa, Lisgala, Suprema, Condessa, Daiane, Duquesa, Imperatriz e Joaquina. As cultivares de macieira Condessa, Princesa, Eva, Duquesa, Imperatriz, Gala, Fred Hough, Daiane, Baronesa e Suprema produzem pólen em quantidade suficiente e com boa capacidade germinativa. A cv. Condessa, embora apresente alta capacidade germinativa de pólen, produz menos anteras e grãos de pólen por antera que as demais. A cv. Princesa é a que apresenta o melhor perfil como polinizadora, por conjugar número de anteras/flor, número de grãos de pólen/antera e capacidade germinativa do pólen mais satisfatórios.

  10. Revisiting Causality in Markov Chains

    CERN Document Server

    Shojaee, Abbas

    2016-01-01

    Identifying causal relationships is a key premise of scientific research. The growth of observational data in different disciplines along with the availability of machine learning methods offers the possibility of using an empirical approach to identifying potential causal relationships, to deepen our understandings of causal behavior and to build theories accordingly. Conventional methods of causality inference from observational data require a considerable length of time series data to capture cause-effect relationship. We find that potential causal relationships can be inferred from the composition of one step transition rates to and from an event. Also known as Markov chain, one step transition rates are a commonly available resource in different scientific disciplines. Here we introduce a simple, effective and computationally efficient method that we termed 'Causality Inference using Composition of Transitions CICT' to reveal causal structure with high accuracy. We characterize the differences in causes,...

  11. Composição florística de uma floresta estacional semidecidual montana no município de Viçosa-MG Floristic composition of a montane seasonal semideciduous tropical forest in Viçosa, MG, Brasil

    Directory of Open Access Journals (Sweden)

    João Augusto Alves Meira-Neto

    2002-08-01

    Full Text Available O objetivo do presente estudo foi investigar a composição florística arbórea da Mata da Silvicultura (20º45'S e 42º55'W, município de Viçosa, Zona da Mata de Minas Gerais, com o intuito de avaliar sua similaridade com outras florestas. Para comparação florística foi utilizada a análise de agrupamentos pelo método de médias aritméticas não-ponderadas (UPGMA, a partir dos índices binários de similaridade de Sørensen entre as florestas comparadas. Foram relacionadas 154 espécies de 47 famílias botânicas para a Mata da Silvicultura. Esta mata mostrou-se mais similar às florestas semideciduais de altitude de Lavras (MG e de Atibaia (SP e menos similar às florestas submontanas e litorâneas. Estes resultados evidenciam uma importante influência das temperaturas na determinação do tipo florístico das florestas do Sudeste e Sul brasileiros.This study aims to investigate the floristic composition of the Silvicultura forest (20º45`S and 42º55´W by comparing it to other forest compositions. Thus, the cluster analysis method of unweighted pair-group using arithmetic averages (UPGMA was used, applying the Sørensen binary similarity index found among compared forests. A list of 154 species of 47 families was recorded. The Silvicultura forest is more similar to the montane semideciduous forests of Lavras and Atibaia, but less similar to submontane and coastal forests. These results show that temperature plays an important role in the floristic differentiation of the southern and southeastern Brazilian forest types.

  12. Condicionamento fisiológico de sementes de couve-flor Priming seed treatment of cauliflower seeds

    Directory of Open Access Journals (Sweden)

    Ana Lúcia P Kikuti

    2009-06-01

    Full Text Available Esta pesquisa teve como objetivos definir o procedimento para o condicionamento fisiológico de sementes de couve-flor e verificar a influência do potencial fisiológico das sementes sobre os resultados desse tratamento. Seis lotes de sementes, três da cultivar Sharon e três da cultivar Teresópolis Gigante, foram submetidos ao hidrocondicionamento entre camadas de duas, quatro e seis folhas de papel toalha e ao osmocondicionamento entre camadas de quatro folhas de papel toalha umedecidas com solução de polietilenoglicol 6000 (potenciais de -0,1 e -0,2 MPa. Em todos os procedimentos os teores de água foram ajustados para 32 e 38%, para a cultivar Sharon, e 34 e 41% para a cultivar Teresópolis Gigante. Os efeitos dos tratamentos sobre a germinação e emergência das plântulas foram comparados à testemunha (sem condicionamento. O hidrocondicionamento entre quatro e seis folhas, até a obtenção dos teores de água mais elevados, beneficiou a velocidade de germinação (VG e a de emergência de plântulas (VE, nas duas cultivares. Na cultivar Sharon a VG foi de 14,6 (testemunha em comparação a 16,4 nas sementes hidrocondicionadas, para os lotes de maior e menor potencial fisiológico; paralelamente, os valores da VE aumentaram de 8,9 para 11,2 e de 7,8 para 11,6, nos lotes de menor potencial fisiológico. Para a cultivar Teresópolis Gigante, a VG e a VE foram favorecidas pelo hidrocondicionamento, independentemente do potencial fisiológico dos lotes (a VG aumentou de 16,4 para 21,4 e, a VE, de 9,5 para 13,5. Conclui-se que o hidrocondicionamento entre quatro e seis folhas de papel toalha, até a obtenção de teores de água próximos aos da emissão da raiz primária é favorável à velocidade de germinação e de emergência de plântulas em couve-flor e que o potencial fisológico inicial dos lotes pode influenciar a resposta ao condicionamento fisiológico, dependendo da cultivar ou histórico dos lotes.This research was

  13. Quantum information causality.

    Science.gov (United States)

    Pitalúa-García, Damián

    2013-05-24

    How much information can a transmitted physical system fundamentally communicate? We introduce the principle of quantum information causality, which states the maximum amount of quantum information that a quantum system can communicate as a function of its dimension, independently of any previously shared quantum physical resources. We present a new quantum information task, whose success probability is upper bounded by the new principle, and show that an optimal strategy to perform it combines the quantum teleportation and superdense coding protocols with a task that has classical inputs. PMID:23745844

  14. Inferring deterministic causal relations

    OpenAIRE

    Daniusis, Povilas; Janzing, Dominik; Mooij, Joris; Zscheischler, Jakob; Steudel, Bastian; Zhang, Kun; Schoelkopf, Bernhard

    2012-01-01

    We consider two variables that are related to each other by an invertible function. While it has previously been shown that the dependence structure of the noise can provide hints to determine which of the two variables is the cause, we presently show that even in the deterministic (noise-free) case, there are asymmetries that can be exploited for causal inference. Our method is based on the idea that if the function and the probability density of the cause are chosen independently, then the ...

  15. Resposta de brócolis, couve-flor e repolho à adubação com boro em solo arenoso Response of boron fertilization on broccoli, cauliflower and cabbage planted in sandy soil

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Pizetta

    2005-03-01

    Full Text Available Foram avaliados em condições de campo, em solo arenoso, com baixo teor de boro, os efeitos da adubação com cinco doses de boro (0; 2; 4; 6 e 8 kg ha-1 de B na forma de bórax na produção de brócolis, couve-flor e repolho. O experimento obedeceu a um esquema fatorial com delineamento experimental de blocos ao acaso com três repetições. As adubações orgânica e química, inclusive o bórax, foram feitas no sulco antes do transplantio das mudas e a colheita foi feita entre 63 e 93 dias após o transplantio. A produtividade de brócolis variou de 16,9 a 20,5 t ha-1; a de couve-flor de 21,6 a 29,6 t ha-1 e a de repolho de 40,5 a 46,4 t ha-1. O aumento observado na produtividade de brócolis e de repolho foi linear e o efeito das doses de boro na produtividade de couve-flor foi quadrático, sendo necessários 5,1 kg ha-1 de B para atingir a produtividade máxima de 30 t ha-1. Brócolis e repolho mostraram-se menos sensíveis do que a couve-flor tanto à deficiência quanto ao excesso de boro. No caso da couve-flor, com a aplicação de 2 kg ha-1 ou de 6 kg ha-1 de B houve significativa perda de qualidade do produto.The effects of boron fertilization on yield of broccoli, cauliflower and cabbage were evaluated through a field experiment carried out on a sandy soil low in available boron. Five boron levels (0; 2; 4; 6; and 8 kg ha-1 B as borax were applied in broccoli, cauliflower and cabbage using a factorial scheme and a randomized block design with three replicates. Organic manure and chemical fertilizers, including borax, were applied in the planting furrow before seedlings transplant and plants were harvested 63 to 93 days after planting date. The yield intervals obtained with broccoli, cauliflower and cabbage varied according to the following intervals: 16.9 to 20.5 t ha-1, 21.6 to 29.6 t ha-1 and 40.5 to 46.3 t ha-1, respectively. The increase in production observed in broccoli and cabbage yield was linear with boron levels and the

  16. Composição florística de trechos florestais na borda sul-amazônica Floristic composition of forest patches in Southern Amazonia

    Directory of Open Access Journals (Sweden)

    Natália Macedo Ivanauskas

    2004-09-01

    Full Text Available Este estudo apresenta a composição florística de trechos de uma faixa de vegetação de transição existente na região centro-leste do Estado de Mato Grosso, mais precisamente no município de Gaúcha do Norte (13° 10'S e 53° 15' O, onde dá-se o contato entre a Floresta Ombrófila e a Floresta Estacional. O levantamento florístico foi realizado em março de 1999 e bimestralmente a partir de agosto de 1999 até março de 2001, em excursões com duração média de 5 dias, por meio de caminhadas na borda e no interior de florestas, sendo coletadas fanerógamas em fase reprodutiva. Também foram incluídas amostras vegetativas de espécies arbustivo-arbóreas, que não floresceram ou frutificaram durante o período de amostragem, amostradas em 3ha destinados ao levantamento fitossociológico. O levantamento florístico resultou em 72 famílias, 168 gêneros e 268 espécies. Do total de espécies, 66% apresentaram hábito arbóreo e 18% foram lianas. As ervas e arbustos praticamente restringiram-se às áreas de borda ou clareiras, somando 13%. Já a flora epifítica mostrou-se pouco expressiva (1%, quando comparada ao restante da Amazônia, em conseqüência do clima regional mais seco. Hemiepífitas, parasitas e palmeiras constituíram o percentual restante. Constatou-se que 39 espécies amostradas em Gaúcha do Norte ainda não haviam sido depositadas em herbários que mantém coleções representativas da flora matogrossense, enfatizando a carência de coletas nas áreas florestais do Estado.This paper shows the floristic composition of forest patches in a zone of transition vegetation which exists in the central-east region of Mato Grosso state, more specifically in the municipality of Gaúcha do Norte (13° 10'S and 53° 15' W where it connects the tropical rain-forest and the seasonal forest. The floristic survey was performed in March 1999 and bisemesterly from August 1999 to March 2001 (during excursions of an average of five days

  17. Causal inference based on counterfactuals

    Directory of Open Access Journals (Sweden)

    Höfler M

    2005-09-01

    Full Text Available Abstract Background The counterfactual or potential outcome model has become increasingly standard for causal inference in epidemiological and medical studies. Discussion This paper provides an overview on the counterfactual and related approaches. A variety of conceptual as well as practical issues when estimating causal effects are reviewed. These include causal interactions, imperfect experiments, adjustment for confounding, time-varying exposures, competing risks and the probability of causation. It is argued that the counterfactual model of causal effects captures the main aspects of causality in health sciences and relates to many statistical procedures. Summary Counterfactuals are the basis of causal inference in medicine and epidemiology. Nevertheless, the estimation of counterfactual differences pose several difficulties, primarily in observational studies. These problems, however, reflect fundamental barriers only when learning from observations, and this does not invalidate the counterfactual concept.

  18. Experimental test of nonlocal causality.

    Science.gov (United States)

    Ringbauer, Martin; Giarmatzi, Christina; Chaves, Rafael; Costa, Fabio; White, Andrew G; Fedrizzi, Alessandro

    2016-08-01

    Explaining observations in terms of causes and effects is central to empirical science. However, correlations between entangled quantum particles seem to defy such an explanation. This implies that some of the fundamental assumptions of causal explanations have to give way. We consider a relaxation of one of these assumptions, Bell's local causality, by allowing outcome dependence: a direct causal influence between the outcomes of measurements of remote parties. We use interventional data from a photonic experiment to bound the strength of this causal influence in a two-party Bell scenario, and observational data from a Bell-type inequality test for the considered models. Our results demonstrate the incompatibility of quantum mechanics with a broad class of nonlocal causal models, which includes Bell-local models as a special case. Recovering a classical causal picture of quantum correlations thus requires an even more radical modification of our classical notion of cause and effect. PMID:27532045

  19. Relationship of causal effects in a causal chain and related inference

    Institute of Scientific and Technical Information of China (English)

    GENG; Zhi; HE; Yangbo; WANG; Xueli

    2004-01-01

    This paper discusses the relationship among the total causal effect and local causal effects in a causal chain and identifiability of causal effects. We show a transmission relationship of causal effects in a causal chain. According to the relationship, we give an approach to eliminating confounding bias through controlling for intermediate variables in a causal chain.

  20. Relativistic hydrodynamics - causality and stability

    OpenAIRE

    Ván, P.; Biró, T. S.

    2007-01-01

    Causality and stability in relativistic dissipative hydrodynamics are important conceptual issues. We argue that causality is not restricted to hyperbolic set of differential equations. E.g. heat conduction equation can be causal considering the physical validity of the theory. Furthermore we propose a new concept of relativistic internal energy that clearly separates the dissipative and non-dissipative effects. We prove that with this choice we remove all known instabilities of the linear re...

  1. Causality Statistical Perspectives and Applications

    CERN Document Server

    Berzuini, Carlo; Bernardinell, Luisa

    2012-01-01

    A state of the art volume on statistical causality Causality: Statistical Perspectives and Applications presents a wide-ranging collection of seminal contributions by renowned experts in the field, providing a thorough treatment of all aspects of statistical causality. It covers the various formalisms in current use, methods for applying them to specific problems, and the special requirements of a range of examples from medicine, biology and economics to political science. This book:Provides a clear account and comparison of formal languages, concepts and models for statistical causality. Addr

  2. Estudo do sistema de reprodução da fava-d'anta (Dimorphandra mollis Benth.

    Directory of Open Access Journals (Sweden)

    A.D.R. Mendes

    2013-01-01

    Full Text Available Entre as plantas nativas de uso medicinal do Cerrado brasileiro encontra-se a fava-d'anta (Dimorphandra mollis Benth com alto potencial econômico por possuir inúmeras potencialidades medicinais e fitoquímicas. A indústria extrai dos frutos os princípios ativos rutina, quercetina, e ramnose, dentre outros, usados na fabricação de medicamentos e cosméticos, principalmente no exterior. O conhecimento do sistema reprodutivo da espécie é fundamental para sua conservação e manejo. O presente trabalho objetivou determinar as características morfométricas das flores e caracterizar o sistema reprodutivo da D. mollis em área de Cerrado inalterada antropomorficamente, no município de Olhos D'água - MG. Para as características morfométricas, diâmetro da flor, comprimento da flor, do ovário, e da antera, foram utilizadas cinco flores em pré-antese. Para a determinação do sistema reprodutivo utilizou-se a razão pólen:óvulo (P:O, em 40 flores. As flores da D. mollis apresentaram comprimento da flor de 3,00 mm, diâmetro da flor de 2,00 mm, comprimento do óvulo de 2,60 mm, comprimento da antera de 1,57 mm, e o número de óvulos e de anteras foram 20 e 5,8, respectivamente. A razão P:O foi 765,030, sendo que esse índice não é afetado pelas características morfométricas. O sistema reprodutivo da D. mollis foi classificado como alógama facultativa.

  3. Leonardo da Vinci, enginyer

    OpenAIRE

    Barca Salom, Francesc Xavier

    2011-01-01

    El dissabte 15 d’abril de 1452, vigília de la Setmana Santa, va néixer a Archiamo prop de Vinci un nen a qui el seu avi patern va batejar com Leonardo. Era fill il·legítim del notari florentí Ser Piero da Vinci i d’una camperola anomenada Caterina. El seu avi patern, Antonio, que no era notari (encara que descendia d’una nissaga de notaris), se’n feu càrrec d’aquest nen des del seu naixement, mentre que el seu pare marxà a Florència per casar-se amb Albiera di Giovanni Amadori....

  4. Inferring deterministic causal relations

    CERN Document Server

    Daniusis, Povilas; Mooij, Joris; Zscheischler, Jakob; Steudel, Bastian; Zhang, Kun; Schoelkopf, Bernhard

    2012-01-01

    We consider two variables that are related to each other by an invertible function. While it has previously been shown that the dependence structure of the noise can provide hints to determine which of the two variables is the cause, we presently show that even in the deterministic (noise-free) case, there are asymmetries that can be exploited for causal inference. Our method is based on the idea that if the function and the probability density of the cause are chosen independently, then the distribution of the effect will, in a certain sense, depend on the function. We provide a theoretical analysis of this method, showing that it also works in the low noise regime, and link it to information geometry. We report strong empirical results on various real-world data sets from different domains.

  5. Algas planctônicas de um lago artificial do Jardim Botânico Chico Mendes, Goiânia, Goiás: florística e algumas considerações ecológicas

    OpenAIRE

    I.S. NOGUEIRA; LEANDRO-RODRIGUES N. C.

    1999-01-01

    Este trabalho visa estudar a composição e fazer algumas considerações ecológicas das algas planctônicas que ocorrem em um dos lagos artificiais do Jardim Botânico Chico Mendes, Goiânia, Goiás, enfocando a florística e aspectos ecológicos entre períodos de seca, início de chuva e período chuvoso, juntamente com alguns parâmetros abióticos (pH, oxigênio - dissolvido e saturado - temperatura do ar e da água, nitratos, nitritos, alcalinidade, cloretos, turbidez, DBO e precipitação). Foram reconhe...

  6. Causal Inference and Developmental Psychology

    Science.gov (United States)

    Foster, E. Michael

    2010-01-01

    Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether…

  7. Re-thinking local causality

    NARCIS (Netherlands)

    Friederich, Simon

    2015-01-01

    There is widespread belief in a tension between quantum theory and special relativity, motivated by the idea that quantum theory violates J. S. Bell's criterion of local causality, which is meant to implement the causal structure of relativistic space-time. This paper argues that if one takes the es

  8. Expert Causal Reasoning and Explanation.

    Science.gov (United States)

    Kuipers, Benjamin

    The relationship between cognitive psychologists and researchers in artificial intelligence carries substantial benefits for both. An ongoing investigation in causal reasoning in medical problem solving systems illustrates this interaction. This paper traces a dialectic of sorts in which three different types of causal resaoning for medical…

  9. AVALIAÇÃO DO ESTADO NUTRICIONAL DE PLANTAS DE COUVE-FLOR CULTIVADAS EM SOLUÇÃO NUTRITIVA SUPRIMIDAS DE MACRONUTRIENTES

    Directory of Open Access Journals (Sweden)

    ROMUALDO, Liliane Maria

    2009-04-01

    Full Text Available An experiment was conducted under greenhouse conditions, to evaluate the effects of macronutrient omission on cauliflower nutritional status and development, as well as describe nutritionaldeficiency symptoms. The experiment was arranged in completely randomized design with three replications and seven treatments, corresponding to complete nutritive solution and individual N, P, K,Ca, Mg and S omission. Plant height, number of leaves, leaf area, shoot, root and whole plant dry mass and macronutrient levels were determined and nutritional deficiency symptoms were described.Individual omissions of N, P, K or Ca were the most limiting for cauliflower growth, considerably reducing plant height, number of leaves, and shoot, root and whole plant dry mass. Nutritional deficiency symptoms were observed for each element. Shoot macronutrient levels in control and nutrient omission treatments were, respectively: N = 36.3 – 11.0; P = 5.0 – 1.0; K = 37.0 – 4.7; Ca = 26.0 – 5.7; Mg = 5.3 – 1.0; S = 15.0 – 3.0 g kg-1.Com o objetivo de avaliar o efeito da omissão de macronutrientes no crescimento e noestado nutricional da couve-flor, bem como descrever sintomas visuais de deficiência nutricional, foiconduzido um experimento em casa de vegetação, em solução nutritiva. O delineamento experimental foiinteiramente casualizado, com sete tratamentos, que corresponderam à solução completa e à omissãoindividual de N, P, K, Ca, Mg e S, com três repetições. Foram avaliados a altura das plantas, o número defolhas, a área foliar, a massa seca da parte aérea, das raízes e planta inteira, os teores dos macronutrientesda parte aérea e raízes e descritas as desordens nutricionais. As omissões individuais de N, P, K, Ca e Mgforam as mais limitantes para o crescimento vegetativo da couve-flor, reduzindo consideravelmente aaltura, o número de folhas, área foliar, assim como massa seca da parte aérea, raízes e planta inteira.Foram observados

  10. BENITO, NUEVO MUTANTE DE FLOR DE JAMAICA (Hibiscus sabdariffa, L.) DE ALTO POTENCIAL PRODUCTIVO EN CONDICIONES DE BAJOS SUMINISTROS DE AGUA

    OpenAIRE

    María C. González Cepero

    2015-01-01

    En el Instituto Nacional de Ciencias Agrícolasse desarrolló un programa de mejoramiento genético dirigidoa obtener variedades de Flor de Jamaica de alto potencialproductivo, en condiciones de bajos suministros de agua.

  11. The Visual Causality Analyst: An Interactive Interface for Causal Reasoning.

    Science.gov (United States)

    Wang, Jun; Mueller, Klaus

    2016-01-01

    Uncovering the causal relations that exist among variables in multivariate datasets is one of the ultimate goals in data analytics. Causation is related to correlation but correlation does not imply causation. While a number of casual discovery algorithms have been devised that eliminate spurious correlations from a network, there are no guarantees that all of the inferred causations are indeed true. Hence, bringing a domain expert into the casual reasoning loop can be of great benefit in identifying erroneous casual relationships suggested by the discovery algorithm. To address this need we present the Visual Causal Analyst-a novel visual causal reasoning framework that allows users to apply their expertise, verify and edit causal links, and collaborate with the causal discovery algorithm to identify a valid causal network. Its interface consists of both an interactive 2D graph view and a numerical presentation of salient statistical parameters, such as regression coefficients, p-values, and others. Both help users in gaining a good understanding of the landscape of causal structures particularly when the number of variables is large. Our framework is also novel in that it can handle both numerical and categorical variables within one unified model and return plausible results. We demonstrate its use via a set of case studies using multiple practical datasets. PMID:26529703

  12. Época de aplicação de fungicida para controle da mancha de Mycosphaerella do morangueiro Timing of fungicide application for Mycosphaerella leaf spot control on strawberry

    Directory of Open Access Journals (Sweden)

    Cleber Furlanetto

    1999-11-01

    Full Text Available Estudou-se o efeito da época do início da aplicação de fungicida na severidade da mancha de Mycosphaerella fragariae em parcelas experimentais de morango cv. IAC-Campinas. O ensaio foi conduzido em área produtora (Brazlândia, DF em blocos ao acaso com seis tratamentos (épocas de início de pulverização e quatro repetições. Foram efetuadas aplicações quinzenais com o p.a. prochloraz (450 g i.a/litro na dosagem de 100 ml/100 litros de água, e testadas as épocas de início de aplicação: Plantio (pulverização por ocasião do plantio das mudas, com um total de dez aplicações; Flor1 (após a primeira florada, oito aplicações; Flor2 (após a segunda florada, seis aplicações; Flor3 (após a terceira florada, quatro aplicações; Flor4 (após a quarta florada, duas aplicações e Test (testemunha pulverizada com água desde o transplantio. As seguintes variáveis foram avaliadas: produção total acumulada; severidade de doença; número de folhas mortas e sadias; número de hastes lesionadas e sadias. Os resultados indicaram que os tratamentos Plantio e Flor1 foram superiores aos demais em todos os critérios (Duncan, 5%. O tratamento Flor2 apresentou controle intermediário de doença. Os demais tratamentos não apresentaram diferenças estatísticas significativas entre si.The effect of timing of first fungicide application on the severity of Mycosphaerella leaf spot (Mycosphaerella fragariae on strawberry cv. IAC-Campinas was studied in field plots located in Brazlândia-DF, Brazil. The experiment was conducted as a randomized complete block design with six treatments (times of first fungicide delivery and four replicates. The fungicide (prochloraz - 450 g a.i./L was delivered at a dosage of 100 ml/100 L of water, on a 15-day schedule. The following periods for first application were tested: "Plant": at transplant stage; with a total of ten fungicide applications; "Flor1": at first flowering stage, total of eight applications

  13. ["Karoshi" and causal relationships].

    Science.gov (United States)

    Hamajima, N

    1992-08-01

    This paper aims to introduce a measure for use by physicians for stating the degree of probable causal relationship for "Karoshi", ie, a sudden death from cerebrovascular diseases or ischemic heart diseases under occupational stresses, as well as to give a brief description for legal procedures associated with worker's compensation and civil trial in Japan. It is a well-used measure in epidemiology, "attributable risk percent (AR%)", which can be applied to describe the extent of contribution to "Karoshi" of the excess occupational burdens the deceased worker was forced to bear. Although several standards such as average occupational burdens for the worker, average occupational burdens for an ordinary worker, burdens in a nonoccupational life, and a complete rest, might be considered for the AR% estimation, the average occupational burdens for an ordinary worker should normally be utilized as a standard for worker's compensation. The adoption of AR% could be helpful for courts to make a consistent judgement whether "Karoshi" cases are compensatable or not. PMID:1392028

  14. Principal stratification in causal inference.

    Science.gov (United States)

    Frangakis, Constantine E; Rubin, Donald B

    2002-03-01

    Many scientific problems require that treatment comparisons be adjusted for posttreatment variables, but the estimands underlying standard methods are not causal effects. To address this deficiency, we propose a general framework for comparing treatments adjusting for posttreatment variables that yields principal effects based on principal stratification. Principal stratification with respect to a posttreatment variable is a cross-classification of subjects defined by the joint potential values of that posttreatment variable tinder each of the treatments being compared. Principal effects are causal effects within a principal stratum. The key property of principal strata is that they are not affected by treatment assignment and therefore can be used just as any pretreatment covariate. such as age category. As a result, the central property of our principal effects is that they are always causal effects and do not suffer from the complications of standard posttreatment-adjusted estimands. We discuss briefly that such principal causal effects are the link between three recent applications with adjustment for posttreatment variables: (i) treatment noncompliance, (ii) missing outcomes (dropout) following treatment noncompliance. and (iii) censoring by death. We then attack the problem of surrogate or biomarker endpoints, where we show, using principal causal effects, that all current definitions of surrogacy, even when perfectly true, do not generally have the desired interpretation as causal effects of treatment on outcome. We go on to forrmulate estimands based on principal stratification and principal causal effects and show their superiority. PMID:11890317

  15. Classical planning and causal implicatures

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Benotti, Luciana

    In this paper we motivate and describe a dialogue manager (called Frolog) which uses classical planning to infer causal implicatures. A causal implicature is a type of Gricean relation implicature, a highly context dependent form of inference. As we shall see, causal implicatures are important for...... generate clarification requests"; as a result we can model task-oriented dialogue as an interactive process locally structured by negotiation of the underlying task. We give several examples of Frolog-human dialog, discuss the limitations imposed by the classical planning paradigm, and indicate the...

  16. Functional equations with causal operators

    CERN Document Server

    Corduneanu, C

    2003-01-01

    Functional equations encompass most of the equations used in applied science and engineering: ordinary differential equations, integral equations of the Volterra type, equations with delayed argument, and integro-differential equations of the Volterra type. The basic theory of functional equations includes functional differential equations with causal operators. Functional Equations with Causal Operators explains the connection between equations with causal operators and the classical types of functional equations encountered by mathematicians and engineers. It details the fundamentals of linear equations and stability theory and provides several applications and examples.

  17. Análise da Relação Causal entre Imagem, Qualidade, Satisfação e Fidelidade: um estudo sobre a percepção do turista nacional no destino turístico Natal-RN

    Directory of Open Access Journals (Sweden)

    Sérgio Marques Júnior

    2011-01-01

    Full Text Available O objetivo principal do estudo é analisar a relação causal existente entre a qualidade, a satisfação, a fidelidade e a imagem de destinos. Para tanto, se realizou um estudo exploratório-descritivo, do tipo Survey, com enfoque analítico quantitativo. A coleta de dados foi realizada através de questionário aplicado junto aos turistas nacionais no Aeroporto Internacional Augusto Severo e na Rodoviária da Cidade do Natal, principais locais de entrada e saída de turistas no local. A composição amostral foi aleatória simples chegando-se ao número final de 400 turistas entrevistados. Dentre os principais resultados, observou-se que são nove as dimensões da percepção de qualidade de destinos de Sol e Praia, ou seja, Praias e Facilidades, Equipamentos Públicos, Alimentos e Bebidas, Serviços de Transportes, Equipamentos do Hotel, Serviços do Hotel, Entretenimento e Atrativos, Acesso ao Hotel e Hospitalidade. Concluiu-se que a imagem exerce influência forte e direta tanto no processo de satisfação do consumidor quanto no de fidelização. As dimensões da qualidade encontradas também se apresentaram como fortes influenciadoras de ambos os fatores, sendo que a satisfação influencia de forma direta a fidelização ao destino.

  18. Diversidad florística asociada a las lagunas andinas Pomacocha y Habascocha, Junín, Perú

    Directory of Open Access Journals (Sweden)

    Mercedes Flores

    2013-05-01

    Full Text Available Se realizó un estudio de la diversidad florística de los alrededores de las lagunas Pomacocha y Habascocha (4350 - 4550 m de altitud, 11°45’-11°48’S y 75°12’-75°15’O, Provincia de Concepción, Junín, Perú. Se han registrado 29 familias, 64 géneros y 100 especies. Poaceae fue la familia con mayor diversidad específica (25%, seguida por Asteraceae (24% y Gentianaceae (6%. Se hace una comparación de la composición florística de la puna de Concepción con la de otras localidades de la puna del Perú.

  19. Use of a flor velum yeast for modulating colour, ethanol and major aroma compound contents in red wine.

    Science.gov (United States)

    Moreno, Juan; Moreno-García, Jaime; López-Muñoz, Beatriz; Mauricio, Juan Carlos; García-Martínez, Teresa

    2016-12-15

    The most important and negative effect of the global warming for winemakers in warm and sunny regions is the observed lag between industrial and phenolic grape ripeness, so only it is possible to obtain an acceptable colour when the ethanol content of wine is high. By contrast, the actual market trends are to low ethanol content wines. Flor yeast growing a short time under velum conditions, decreases the ethanol and volatile acidity contents, has a favorable effect on the colour and astringency and significantly changes the wine content in 1-propanol, isobutanol, acetaldehyde, 1,1-diethoxiethane and ethyl lactate. The Principal Component Analysis of six enological parameters or five aroma compounds allows to classify the wines subjected to different velum formation conditions. The obtained results in two tasting sessions suggest that the flor yeast helps to modulate the ethanol, astringency and colour and supports a new biotechnological perspective for red winemakers. PMID:27451159

  20. On causality of extreme events

    CERN Document Server

    Zanin, Massimiliano

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect both linear and non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task.

  1. Causal reasoning with mental models

    OpenAIRE

    Khemlani, Sangeet S.; Barbey, Aron K.; Johnson-Laird, Philip N

    2014-01-01

    This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews e...

  2. Consciousness and the "Causal Paradox"

    OpenAIRE

    Velmans, Max

    1996-01-01

    Viewed from a first-person perspective consciousness appears to be necessary for complex, novel human activity - but viewed from a third-person perspective consciousness appears to play no role in the activity of brains, producing a "causal paradox". To resolve this paradox one needs to distinguish consciousness of processing from consciousness accompanying processing or causing processing. Accounts of consciousness/brain causal interactions switch between first- and third-person perspectives...

  3. Realist Magic : Objects, Ontology, Causality

    OpenAIRE

    Morton, Timothy

    2013-01-01

    Object-oriented ontology offers a startlingly fresh way to think about causality that takes into account developments in physics since 1900. Causality, argues, Object Oriented Ontology (OOO), is aesthetic. In this book, Timothy Morton explores what it means to say that a thing has come into being, that it is persisting, and that it has ended. Drawing from examples in physics, biology, ecology, art, literature and music, Morton demonstrates the counterintuitive yet elegant explanatory power of...

  4. Correlation Measure Equivalence in Dynamic Causal Structures

    CERN Document Server

    Gyongyosi, Laszlo

    2016-01-01

    We prove an equivalence transformation between the correlation measure functions of the causally-unbiased quantum gravity space and the causally-biased standard space. The theory of quantum gravity fuses the dynamic (nonfixed) causal structure of general relativity and the quantum uncertainty of quantum mechanics. In a quantum gravity space, the events are causally nonseparable and all time bias vanishes, which makes it no possible to use the standard causally-biased entropy and the correlation measure functions. Since a corrected causally-unbiased entropy function leads to an undefined, obscure mathematical structure, in our approach the correction is made in the data representation of the causally-unbiased space. We prove that the standard causally-biased entropy function with a data correction can be used to identify correlations in dynamic causal structures. As a corollary, all mathematical properties of the causally-biased correlation measure functions are preserved in the causally-unbiased space. The eq...

  5. A proteomic and metabolomic approach for understanding the role of the flor yeast mitochondria in the velum formation.

    Science.gov (United States)

    Moreno-García, Jaime; García-Martínez, Teresa; Moreno, Juan; Millán, M Carmen; Mauricio, Juan Carlos

    2014-02-17

    Saccharomyces cerevisiae "flor" yeast shows a strong tolerance to high ethanol concentrations and develops a velum (biofilm) on the wine surface after the alcoholic fermentation of grape must. This velum remains along several years during the so called "biological aging" process in the elaboration of some special wines carried out in specific regions around the world and it contributes to the typical organoleptic characteristics of these wines. In order to grow in this condition, flor yeast has to elaborate a response where the mitochondrial function is essential. The objective of this study is to elucidate the role of the mitochondria in the response of a flor yeast, S. cerevisiae G1, growing in a controlled velum formation condition. For this purpose, proteome and metabolome were characterized by comparing data with those from an initial fermentative condition used as reference. The obtained proteomic profiles show more mitochondrial proteins related with the ethanol resistance (13), cell respiration (18), mitochondrial genome maintenance (13), and apoptosis (2) detected under the velum formation condition. Also, the finger-printing obtained by means of the exo-metabolites directly related with the quality of fermented beverages and quantified in the velum condition shows important differences from those obtained in the reference condition. PMID:24361829

  6. Causality, causality, causality: the view of education inputs and outputs from economics

    OpenAIRE

    Lisa Barrow; Cecilia Elena Rouse

    2005-01-01

    Educators and policy makers are increasingly intent on using scientifically-based evidence when making decisions about education policy. Thus, education research today must necessarily be focused on identifying the causal relationships between education inputs and student outcomes. In this paper we discuss methodologies for estimating the causal effect of resources on education outcomes; we also review what we believe to be the best evidence from economics on a few important inputs: spending,...

  7. Causality in physiological signals.

    Science.gov (United States)

    Müller, Andreas; Kraemer, Jan F; Penzel, Thomas; Bonnemeier, Hendrik; Kurths, Jürgen; Wessel, Niels

    2016-05-01

    Health is one of the most important non-material assets and thus also has an enormous influence on material values, since treating and preventing diseases is expensive. The number one cause of death worldwide today originates in cardiovascular diseases. For these reasons the aim of understanding the functions and the interactions of the cardiovascular system is and has been a major research topic throughout various disciplines for more than a hundred years. The purpose of most of today's research is to get as much information as possible with the lowest possible effort and the least discomfort for the subject or patient, e.g. via non-invasive measurements. A family of tools whose importance has been growing during the last years is known under the headline of coupling measures. The rationale for this kind of analysis is to identify the structure of interactions in a system of multiple components. Important information lies for example in the coupling direction, the coupling strength, and occurring time lags. In this work, we will, after a brief general introduction covering the development of cardiovascular time series analysis, introduce, explain and review some of the most important coupling measures and classify them according to their origin and capabilities in the light of physiological analyses. We will begin with classical correlation measures, go via Granger-causality-based tools, entropy-based techniques (e.g. momentary information transfer), nonlinear prediction measures (e.g. mutual prediction) to symbolic dynamics (e.g. symbolic coupling traces). All these methods have contributed important insights into physiological interactions like cardiorespiratory coupling, neuro-cardio-coupling and many more. Furthermore, we will cover tools to detect and analyze synchronization and coordination (e.g. synchrogram and coordigram). As a last point we will address time dependent couplings as identified using a recent approach employing ensembles of time series. The

  8. Hierarchical organisation of causal graphs

    International Nuclear Information System (INIS)

    This paper deals with the design of a supervision system using a hierarchy of models formed by graphs, in which the variables are the nodes and the causal relations between the variables of the arcs. To obtain a representation of the variables evolutions which contains only the relevant features of their real evolutions, the causal relations are completed with qualitative transfer functions (QTFs) which produce roughly the behaviour of the classical transfer functions. Major improvements have been made in the building of the hierarchical organization. First, the basic variables of the uppermost level and the causal relations between them are chosen. The next graph is built by adding intermediary variables to the upper graph. When the undermost graph has been built, the transfer functions parameters corresponding to its causal relations are identified. The second task consists in the upwelling of the information from the undermost graph to the uppermost one. A fusion procedure of the causal relations has been designed to compute the QFTs relevant for each level. This procedure aims to reduce the number of parameters needed to represent an evolution at a high level of abstraction. These techniques have been applied to the hierarchical modelling of nuclear process. (authors). 8 refs., 12 figs

  9. Phytophthora palmivora, agente da podridão de raiz e frutos de mamoeiro no Estado de Alagoas Phytophthora palmivora, causal agent of root and fruit rots of papaya in the State of Alagoas, Brazil

    OpenAIRE

    Juliana Paiva Carnaúba; Márcio Félix Sobral; Daniela Cavalcanti de Medeiros Furtado; Izael Oliveira Silva; Kirley Michelly Marques da Silva; Edna Peixoto da Rocha Amorim

    2006-01-01

    O mamoeiro (Carica papaya) é uma das mais importantes fruteiras tropicais, e seus frutos contribuem com uma produção de 1,65 milhão de toneladas por ano para o Brasil. Um isolado de Phytophthora sp. obtido de frutos de mamoeiro da cultivar Havaí, em Alagoas, foi caracterizado morfologicamente e sua patogenicidade foi confirmada em frutos e mudas deste hospedeiro. Em meio suco V-8, os esporangióforos apresentaram-se delgados, simples ou pouco ramificados, enquanto os esporângios se apresentara...

  10. FlorNExT®, a cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait. stands in Northeastern Portugal

    Directory of Open Access Journals (Sweden)

    Fernando Pérez-Rodríguez

    2016-07-01

    Full Text Available Aim of the study: To introduce and describe FlorNExT®, a free cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait. even-aged stands in the Northeast of Portugal (NE Portugal. Area of study: NE Portugal. Material and methods: FlorNExT® implements a dynamic growth and yield modelling framework which integrates transition functions for dominant height (site index curves and basal area, as well as output functions for tree and stand volume, biomass, and carbon content. Main results: FlorNExT® is freely available from any device with an Internet connection at: http://flornext.esa.ipb.pt/. Research highlights: This application has been designed to make it possible for any stakeholder to easily estimate standing volume, biomass, and carbon content in maritime pine stands from stand data, as well as to estimate growth and yield based on four stand variables: age, density, dominant height, and basal area. FlorNExT® allows planning thinning treatments. FlorNExT® is a fundamental tool to support forest mobilization at local and regional scales in NE Portugal. Keywords: forest management; maritime pine; forest modelling; knowledge transfer tool.

  11. Causal reasoning with mental models.

    Science.gov (United States)

    Khemlani, Sangeet S; Barbey, Aron K; Johnson-Laird, Philip N

    2014-01-01

    This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex. PMID:25389398

  12. Causal reasoning with mental models

    Directory of Open Access Journals (Sweden)

    Sangeet eKhemlani

    2014-10-01

    Full Text Available This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex.

  13. Causal Models for Risk Management

    Directory of Open Access Journals (Sweden)

    Neysis Hernández Díaz

    2013-12-01

    Full Text Available In this work a study about the process of risk management in major schools in the world. The project management tools worldwide highlights the need to redefine risk management processes. From the information obtained it is proposed the use of causal models for risk analysis based on information from the project or company, say risks and the influence thereof on the costs, human capital and project requirements and detect the damages of a number of tasks without tribute to the development of the project. A study on the use of causal models as knowledge representation techniques causal, among which are the Fuzzy Cognitive Maps (DCM and Bayesian networks, with the most favorable MCD technique to use because it allows modeling the risk information witho ut having a knowledge base either itemize.

  14. On Causality in Dynamical Systems

    CERN Document Server

    Harnack, Daniel

    2016-01-01

    Identification of causal links is fundamental for the analysis of complex systems. In dynamical systems, however, nonlinear interactions may hamper separability of subsystems which poses a challenge for attempts to determine the directions and strengths of their mutual influences. We found that asymmetric causal influences between parts of a dynamical system lead to characteristic distortions in the mappings between the attractor manifolds reconstructed from respective local observables. These distortions can be measured in a model-free, data-driven manner. This approach extends basic intuitions about cause-effect relations to deterministic dynamical systems and suggests a mathematically well defined explanation of results obtained from previous methods based on state space reconstruction.

  15. Cohomology with causally restricted supports

    CERN Document Server

    Khavkine, Igor

    2014-01-01

    De Rham cohomology with spacelike compact and timelike compact supports has recently been noticed to be of importance for understanding the structure of classical and quantum field theories on curved spacetimes. We compute these cohomology groups for globally hyperbolic spacetimes in terms of their standard de Rham cohomologies. The calculation exploits the fact that the de Rham-d'Alambert wave operator can be extended to a chain map that is homotopic to zero and that its causal Green function fits into a convenient exact sequence. This method extends also to the Calabi (or Killing-Riemann-Bianchi) complex and possibly other differential complexes. We also discuss generalized causal structures and functoriality.

  16. Flor de Mayo Eugenia, nueva variedad de frijol para riego y temporal en el centro de México Flor de Mayo Eugenia, new bean cultivar for irrigated and rainfall conditions in Central Mexico

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Acosta Gallegos

    2010-12-01

    Full Text Available Dentro del frijol tipo Flor de Mayo, el subtipo 'media oreja' esta cobrando importancia en el norte-centro de México, éste es de tamaño mediano, forma alargada y color rosa atractivo. Se describe una nueva variedad de este tipo de frijol, Flor de Mayo Eugenia (FME. FME se derivó de una cruza interracial entre Flor de Mayo Anita (FMA (raza Jalisco y Rayado Rojo (raza Nueva Granada. El rendimiento promedio de FME en temporal varia de 0.8 a 2.0 t ha-1 y bajo riego el máximo rendimiento ha sido de 3.8 t ha-1. El peso de 100 semillas promedio de diferentes localidades de FME es significativamente superior al de FMA en condiciones de temporal, 32 vs 26 g 100 semillas, y riego 35 vs 31 g 100 semillas. En cuanto la calidad del grano, el tiempo promedio de cocción de FME en cocedor tipo Mattson es 97 min, mientras que el de FMA es de 109 min; el contenido promedio de proteína del grano de FME es 19% en base a peso seco, similar al de FMA, mientras que el contenido de hierro de FME resultó superior al de FMA con 6.1 vs 5 mg 100 g. FME es tolerante a las razas de roya presentes en el Altiplano de México, a la raza 292 de antracnosis y tolerante a los tizones común y de halo.Within 'Flor de Mayo' bean type, the 'media oreja' subtype is becoming important in North-Central México; this last type has a mid-size elongated seed with showy pink color. A new bean cv. of 'media oreja' subtype is described: Flor de Mayo Eugenia (FME. FME was derived from an interracial cross between Flor de Mayo Anita (FMA (Jalisco breed and Rayado Rojo (Nueva Granada breed. The seed yield of FME under rainfall conditions varied from 0.8 to 2.0 t ha-1 and under irrigation the highest yield recorded was 3.8 t ha-1. The 100-seed weight of FME across different locations was significantly superior to the weight of FMA, 32 vs 26 g per 100 seeds under rainfall conditions and 35 vs 31 g per 100 seeds under irrigation conditions. In regard to seed quality, cooking time average of

  17. Composição florística de florestas estacionais ribeirinhas no estado de Mato Grosso do Sul, Brasil Floristic composition of seasonal riparian forests in Mato Grosso do Sul state, Brazil

    Directory of Open Access Journals (Sweden)

    Vivian Ribeiro Baptista-Maria

    2009-06-01

    Full Text Available O presente estudo teve como objetivos caracterizar a composição florística em dois trechos de floresta estacional semidecidual associada ao rio Formoso, Bonito, MS, e em três trechos de florestas estacionais deciduais e semideciduais associadas aos rios Salobra, Salobrinha e Perdido ocorrentes no Parque Nacional da Serra da Bodoquena (76.481 ha - única unidade de Conservação Federal de Proteção Integral implantada no Estado de Mato Grosso do Sul. O levantamento florístico foi realizado mensalmente entre o período de outubro/2004 a março/2006, onde foram coletadas fanerógamas em fase reprodutiva (flores e frutos, através do método de tempo de avaliação. O levantamento florístico resultou em 56 famílias, 184 gêneros e 307 espécies. Do total das espécies, 68% apresentaram hábito arbóreo, 17% arbustos, 14% foram lianas e apenas 1% palmeiras. A família Fabaceae (Leguminosae, representada por 51 (16,6% espécies, foi a de maior riqueza. Os resultados obtidos neste trabalho contribuíram para o conhecimento da flora sul-mato-grossense e sua distribuição geográfica, reforçando a necessidade de conservação destas matas ribeirinhas e fornecendo subsídios para os planos de restauração das áreas degradadas do entorno da unidade de conservação e das áreas de proteção permanente (APP's dos rios ocorrentes na região.This study aimed to characterize the floristic composition in two stretches of seasonal semideciduous forest associated with the Formoso River, Bonito, Mato Grosso do Sul State, and in three stretches of seasonal deciduous and semideciduous forests associated with the Salobra, Salobrinha and Perdido rivers in Bodoquena Plateau National Park (76,481 ha - the only Federal Conservation unit with Integral Protection in the state of Mato Grosso do Sul. The floristic survey was carried out monthly from October/2004 to March/2006, where flowering and fruiting phanerogams were collected by the method of evaluation

  18. On the Axioms of Causal Set Theory

    CERN Document Server

    Dribus, Benjamin F

    2013-01-01

    This paper offers suggested improvements to the causal sets program in discrete gravity, which treats spacetime geometry as an emergent manifestation of causal structure at the fundamental scale. This viewpoint, which I refer to as the causal metric hypothesis, is summarized by Rafael Sorkin's phrase, "order plus number equals geometry." Proposed improvements include recognition of a generally nontransitive causal relation more fundamental than the causal order, an improved local picture of causal structure, development and use of relation space methods, and a new background-independent version of the histories approach to quantum theory. Besides causal set theory, \\`a la Bombelli, Lee, Meyer, and Sorkin, this effort draws on Isham's topos-theoretic framework for physics, Sorkin's quantum measure theory, Finkelstein's causal nets, and Grothendieck's structural principles. This approach circumvents undesirable structural features in causal set theory, such as the permeability of maximal antichains, studied by ...

  19. Granger Causality and Unit Roots

    DEFF Research Database (Denmark)

    Rodríguez-Caballero, Carlos Vladimir; Ventosa-Santaulària, Daniel

    2014-01-01

    The asymptotic behavior of the Granger-causality test under stochastic nonstationarity is studied. Our results confirm that the inference drawn from the test is not reliable when the series are integrated to the first order. In the presence of deterministic components, the test statistic diverges...

  20. Causal feedbacks in climate change

    NARCIS (Netherlands)

    Nes, van E.H.; Scheffer, M.; Brovkin, V.; Lenton, T.M.; Ye, H.; Deyle, E.; Sugihara, G.

    2015-01-01

    The statistical association between temperature and greenhouse gases over glacial cycles is well documented1, but causality behind this correlation remains difficult to extract directly from the data. A time lag of CO2 behind Antarctic temperature—originally thought to hint at a driving role for tem

  1. Causal Behaviour on Carter spacetime

    CERN Document Server

    Blanco, Oihane F

    2015-01-01

    In this work we will focus on the causal character of Carter Spacetime (see B. Carter, Causal structure in space-time, Gen. Rel. Grav. 1 4 337-406, 1971). The importance of this spacetime is the following: for the causally best well behaved spacetimes (the globally hyperbolic ones), there are several characterizations or alternative definitions. In some cases, it has been shown that some of the causal properties required in these characterizations can be weakened. But Carter spacetime provides a counterexample for an impossible relaxation in one of them. We studied the possibility of Carter spacetime to be a counterexample for impossible lessening in another characterization, based on the previous results. In particular, we will prove that the time-separation or Lorentzian distance between two chosen points in Carter spacetime is infinite. Although this spacetime turned out not to be the counterexample we were looking for, the found result is interesting per se and provides ideas for alternate approaches to t...

  2. Causality problem in Economic Science

    Directory of Open Access Journals (Sweden)

    JOSÉ LUIS RETOLAZA

    2007-12-01

    Full Text Available The main point of the paper is the problem of the economy to be consider like a science in the most strict term of the concept. In the first step we are going to tackle a presentation about what we understand by science to subsequently present some of the fallacies which have bring certain scepticism about the scientific character of the investigation in economy, to know: 1 The differences between hard and weak sciences -physics and social; 2 The differences between paradigm, —positivist and phenomenological— 3 The differences between physic causalityand historic causality. In the second step we are going to talk about two fundamental problems which are questioned: 1 the confusion between ontology and gnoseology and, 2 the erroneous concept of causality that commonly is used. In the last step of the paper we are going over the recent models of «causal explanation» and we suggest the probabilistic casualty development next with a more elaborated models of causal explanation, like a way to conjugate the scientific severity with the possibility to tackle complex economic realities.

  3. Obtención de comprimidos conteniendo extractos atomizados de Flor de la Pasión (Passiflora incarnata L.)

    OpenAIRE

    González Ortega, George; Schmidt, Peter Christian

    1995-01-01

    Fueron obtenidos extractos de las partes aéreas de la Flor de Pasión (Passifora incarnata L.) por turbólisis, empleando una mezcla de metanol y agua (40:60 v/v) como líquido extractor. Los extractos fueron concentrados bajo presión reducida y secados por atomización usando, separadamente, el Gelita-Sol-P y la hidroxilapatita como coadyuvantes. Los productos atomizados fueron analizados por microscopia electrónica de barrido y después utilizados en la producción de comprimidos por el método de...

  4. RENDIMIENTO DE SEMILLA, Y SUS COMPONENTES EN FRIJOL FLOR DE MAYO EN EL CENTRO DE MÉXICO

    OpenAIRE

    Edwin J. Barrios-Gómez; Cándido López-Castañeda; Josué Kohashi-Shibata; Acosta-Gallegos, Jorge A.; Salvador Miranda-Colín; Netzahualcóyotl Mayek-Pérez

    2010-01-01

    En el Centro de México el frijol (Phaseolus vulgaris L.) tipo Flor de Mayo (FM) es uno de los tipos comerciales de mayor demanda. El objetivo del presente estudio fue caracterizar variedades de frijol del tipo FM por su rendimiento de semilla y componentes de rendimiento en condiciones de riego y secano. Durante el ciclo primavera-verano de 2007 se diseñaron tres experimentos en bloques completos al azar: uno en Celaya con riegos de auxilio (punta de riego), estado de Guanajuato, y uno en rie...

  5. Composición florística en potreros de Los Tuxtlas, Veracruz, México

    OpenAIRE

    Andr\\u00E9s Lira-Noriega; Sergio Guevara; Javier Laborde; Graciela S\\u00E1nchez-R\\u00EDos

    2007-01-01

    Se hizo un inventario de especies de plantas fanerógamas y pteridofitas en potreros en áreas desprovistas de árboles, en la zona del volcán San Martín Tuxtla, en Los Tuxtlas, Veracruz. Con el fin de tener la composición florística más completa posible, se realizaron muestreos durante la temporada seca y la de lluvia del año de 1992, en dos localidades: el ejido Balzapote y la colonia agrícola-ganadera La Palma. En cada localidad se seleccionaron cinco potreros dominados por esp...

  6. Composição florística e estrutura de uma unidade de manejo florestal sustentável na Floresta Nacional do Tapajós, Pará Floristic composition and structure of a sustainable forest management unit at Tapajos National Forest, Para, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Guimarães Gonçalves

    2008-01-01

    Full Text Available Neste trabalho são discutidos aspectos da composição florística e da estrutura de um povoamento de floresta ombrófila densa submetido a práticas de exploração madeireira de impacto reduzido. O estudo foi conduzido numa unidade de manejo florestal com aproximadamente 3.200 ha, instalada na porção norte da Floresta Nacional do Tapajós (estado do Pará, onde foram extraídos, em média, 23,7 m³ de madeira por hectare. Para representar a variabilidade existente na área experimental, foram estabelecidas aleatoriamente seis parcelas amostrais de um hectare em diferentes quadras de exploração. As análises florístico-estruturais foram realizadas em duas escalas distintas com vistas a atender objetivos específicos: (a em nível de unidade de manejo, para uma caracterização global do povoamento florestal no qual serão baseados estudos subseqüentes; e (b em nível de parcela amostral, para subsidiar o estudo de dados de sensoriamento remoto frente às variações florístico-estruturais observadas. O conjunto de resultados obtidos indicou que a unidade de manejo florestal apresenta uma elevada diversidade florística no componente arbóreo (índice de Shannon-Weaver igual a 4,22. Observou-se que o povoamento é caracterizado pela concentração de uma grande quantidade de indivíduos e espécies em poucas famílias botânicas e por um número elevado de espécies localmente raras. A análise das variações florístico-estruturais entre parcelas amostrais evidenciou diferenças estatísticas significativas quanto à diversidade e a similaridade de espécies e quanto a valores médios de altura total. Adicionalmente, observou-se certa variabilidade nos padrões estruturais em termos de distribuição diamétrica e de valores estimados de volume comercial de madeira.In this work we discuss aspects of the floristic composition and structure of a stand of dense tropical rain forest subjected to low-impact logging practices. We conducted

  7. Evolución de la composición florística Post-fuego en un carrascal de Navarra (n de España

    Directory of Open Access Journals (Sweden)

    Cavero, R. Y.

    1999-12-01

    Full Text Available This paper presents results about floristic composition dynamics during four years after controlled fires in a Mediterranean pin-oak wood in Navarra (N Spain. The samples have been taken from eight permanent 1 m2 plots subjected to different treatments: different fire type, different situation on the field, and with or without not fired soil addition. The regeneration strategies of the species and the influence of the different treatments on the flora are analyzed. The floristic composition dynamics follows a general model: the species began to appear progressively. The number of species grows gradually to reach a maximum between one and three years after the fire. Later, the number of species diminishes. Post fire species are those that existed before the fire, that is to say, there is an autosuccession process.

    [es] Se presentan los resultados de cuatro años de estudio sobre la evolución de la composición florística de un carrascal mediterráneo sometido a fuegos controlados en Navarra (N de España. Los muestreos se han llevado a cabo en ocho cuadrados permanentes de 1 m2 de superficie, cada uno sometido a distinto tratamiento: distinto tipo de fuego, distinta situación en la parcela y adición o no de suelo no quemado. Se analizan la estrategia de regeneración de las especies que aparecen después de los fuegos y la influencia de los tratamientos en la regeneración de la flora. La evolución de la composición florística sigue un modelo general: las especies empiezan a aparecer progresivamente, su número crece hasta obtener un máximo entre el año y los cuatro años después de los fuegos, a partir del cual disminuye. Las especies que aparecen son las mismas que había previamente, es decir, se da un proceso de autosucesión. [fr] On présente les résultats de quatre ans d'étude sur l'évolution de la composition floristique d'un bois de chêne vert méditerranéen soumis à des feux contr

  8. Condicionamento fisiológico de sementes de couve-flor e desempenho das plantas em campo Hydropriming seed treatment and plant field performance

    Directory of Open Access Journals (Sweden)

    Julio Marcos Filho

    2008-06-01

    Full Text Available O condicionamento fisiológico compreende técnicas que estimulam a germinação e contribuem para reduzir a sensibilidade de sementes e de plântulas a estresses. Efeitos sobre a germinação e a emergência de plântulas têm sido amplamente estudados, mas a influência sobre o comportamento das plantas em campo ainda não é totalmente conhecida. Esta pesquisa foi conduzida com o objetivo principal de verificar efeitos do hidrocondicionamento sobre a germinação, emergência de plântulas, desenvolvimento das plantas e produção de couve-flor. Sementes das cultivares de couve-flor Sharon e Teresópolis Gigante, representados por três lotes, foram hidrocondicionados em papel-toalha, a 20ºC, até atingir 38% de água ('Sharon' ou 41% ('Teresópolis Gigante'. Posteriormente, foram secadas em estufa, a 28-30ºC e 45-55% de umidade relativa, até atingirem teores de água de 7,5% a 7,9%. O potencial fisiológico das sementes foi determinado em laboratório, avaliando-se a percentagem e a velocidade de germinação. Posteriormente, efetuou-se a semeadura em bandejas de poliestireno; o transplante para o campo foi efetuado quando as plantas atingiram estádio de quatro folhas definitivas (30 dias após a semeadura. Determinou-se a velocidade e percentagem de emergência das plântulas aos 14 dias após a semeadura; a altura e a massa seca das plantas foram avaliadas aos 14; 30; 56; 74 e 84 dias e o diâmetro médio da cabeça e a produção final, aos 110 dias. O hidrocondicionamento pode favorecer a velocidade de germinação e de emergência de plântulas, mas esses efeitos não são suficientes para persistir durante o desenvolvimento das plantas e afetar a produção final.Priming treatment usually promotes rapid and uniform germination and increases tolerance to different stress conditions. Post-treatment effects on seed germination and seedling emergence have been extensively studied but information of plant performance is less available

  9. Anticipation of physical causality guides eye movements

    OpenAIRE

    Wende, Kim; Theunissen, Laetitia; Missal, Marcus

    2016-01-01

    Causality is a unique feature of human perception. We present here a behavioral investigation of the influence of physical causality during visual pursuit of object collisions. Pursuit and saccadic eye movements of human subjects were recorded during ocular pursuit of two concurrently launched targets, one that moved according to the laws of Newtonian mechanics (the causal target) and the other one that moved in a physically implausible direction (the non-causal target). We found that anticip...

  10. Causal discovery from medical textual data.

    OpenAIRE

    Mani, S.; Cooper, G. F.

    2000-01-01

    Medical records usually incorporate investigative reports, historical notes, patient encounters or discharge summaries as textual data. This study focused on learning causal relationships from intensive care unit (ICU) discharge summaries of 1611 patients. Identification of the causal factors of clinical conditions and outcomes can help us formulate better management, prevention and control strategies for the improvement of health care. For causal discovery we applied the Local Causal Discove...

  11. Estimating causal structure using conditional DAG models

    OpenAIRE

    Oates, Chris J.; Smith, Jim Q.; Mukherjee, Sach

    2014-01-01

    This paper considers inference of causal structure in a class of graphical models called "conditional DAGs". These are directed acyclic graph (DAG) models with two kinds of variables, primary and secondary. The secondary variables are used to aid in estimation of causal relationships between the primary variables. We give causal semantics for this model class and prove that, under certain assumptions, the direction of causal influence is identifiable from the joint observational distribution ...

  12. Representing Personal Determinants in Causal Structures.

    Science.gov (United States)

    Bandura, Albert

    1984-01-01

    Responds to Staddon's critique of the author's earlier article and addresses issues raised by Staddon's (1984) alternative models of causality. The author argues that it is not the formalizability of causal processes that is the issue but whether cognitive determinants of behavior are reducible to past stimulus inputs in causal structures.…

  13. The argumentative impact of causal relations

    DEFF Research Database (Denmark)

    Nielsen, Anne Ellerup

    1996-01-01

    causality, explanation and justification. In certain types of discourse, causal relations also imply an intentional element. This paper describes the way in which the semantic and pragmatic functions of causal markers can be accounted for in terms of linguistic and rhetorical theories of argumentation....

  14. Expectations and Interpretations during Causal Learning

    Science.gov (United States)

    Luhmann, Christian C.; Ahn, Woo-kyoung

    2011-01-01

    In existing models of causal induction, 4 types of covariation information (i.e., presence/absence of an event followed by presence/absence of another event) always exert identical influences on causal strength judgments (e.g., joint presence of events always suggests a generative causal relationship). In contrast, we suggest that, due to…

  15. Principal Stratification in Causal Inference

    OpenAIRE

    Frangakis, Constantine E.; Rubin, Donald B.

    2002-01-01

    Many scientific problems require that treatment comparisons be adjusted for posttreatment variables, but the estimands underlying standard methods are not causal effects. To address this deficiency, we propose a general framework for comparing treatments adjusting for posttreatment variables that yields principal effects based on principal stratification. Principal stratification with respect to a posttreatment variable is a cross-classification of subjects defined by the joint potential valu...

  16. Entanglement, Holography and Causal Diamonds

    CERN Document Server

    de Boer, Jan; Heller, Michal P; Myers, Robert C

    2016-01-01

    We argue that the degrees of freedom in a d-dimensional CFT can be re-organized in an insightful way by studying observables on the moduli space of causal diamonds (or equivalently, the space of pairs of timelike separated points). This 2d-dimensional space naturally captures some of the fundamental nonlocality and causal structure inherent in the entanglement of CFT states. For any primary CFT operator, we construct an observable on this space, which is defined by smearing the associated one-point function over causal diamonds. Known examples of such quantities are the entanglement entropy of vacuum excitations and its higher spin generalizations. We show that in holographic CFTs, these observables are given by suitably defined integrals of dual bulk fields over the corresponding Ryu-Takayanagi minimal surfaces. Furthermore, we explain connections to the operator product expansion and the first law of entanglement entropy from this unifying point of view. We demonstrate that for small perturbations of the va...

  17. PERSPECTIVAS DE UTILIZAÇÃO DA FLOR-DE-SEDA (Calotropis procera NA PRODUÇÃO ANIMAL

    Directory of Open Access Journals (Sweden)

    Roberto Germano Costa

    2009-01-01

    Full Text Available The Calotropis procera has been an alternative feed for the ruminants in the brasilian semiarid region, presenting fast establishment and constant availability of fitomassa, until 3.0 t of DM/cut, in the dry season. On the aspect biochemical studies have detected various active substances as cardiac glycosides, non enzymatic proteins and enzimatics proteins, that can cause toxicity in animals when inserted in their diet. In nutritional terms, this species provides important nutrients with emphasis on protein, average value of 20%, and in vitro digestibility above 70%. It researches they showed that the intake of C. procera by goats and sheep in the form in nature can cause deaths, however, to make the process of hay and silage the toxicological effects are reduced. The utilization of C. procera is promissing, needing studies for maximize of the productivity; biochemical evaluation for identification of active substances, their mechanisms and local action in the animal, as well as testing to obtain the safe levels for inclusion in various forms of supply (in natura, hay and silage.

  18. Produtividade e podridão parda em couve-flor de inverno influenciadas pelo nitrogênio e boro Yield and hollow stem disorder of winter cauliflower influenced by nitrogen and boron

    Directory of Open Access Journals (Sweden)

    Mônica Sartori de Camargo

    2008-01-01

    Full Text Available A podridão parda é um problema comum em couve-flor que ocasiona sintomas semelhantes à deficiência de B. Sua ocorrência está associada, especialmente, ao nitrogênio e boro, mas há escassez de informações no Brasil. O experimento foi realizado de março a junho de 2006 em blocos casualizados com quatro repetições. O objetivo foi avaliar o efeito de doses de nitrogênio (100, 150, 200 e 250 kg ha-1 e boro (0 e 3 kg ha-1 na produtividade e na incidência de podridão parda da couve-flor ‘Júlia’ cultivada em Argissolo Vermelho-Amarelo, em Tietê (SP. A massa, o diâmetro das cabeças e a produtividade total tiveram valores médios satisfatórios: 0,782 kg, 17,74 cm e 15,64 t ha-1 respectivamente. O diâmetro das cabeças não foi influenciado pelos tratamentos, com média de 17,74 cm. As doses crescentes de N aumentaram linearmente a massa, a produtividade total e o teor de N nas cabeças. A aplicação de B aumentou seu teor na cabeça, a produtividade comercial e reduziu a podridão parda. Houve correlação negativa entre o teor de B nas cabeças com a incidência da podridão parda. A adubação com B para a couve-flor cultivada em solo com teor médio desse micronutriente foi necessária para reduzir esse distúrbio fisiológico.The hollow stem disorder is a common problem in cauliflower, resulting in similar symptom to B deficiency. Its occurrence is associated, specially to nitrogen and boron rates. There is few information about this subject in Brazil. The experiment was carried out from March to June/2006 in a randomized complete block design with 4 replications. The objective was to evaluate rates of nitrogen (100, 150, 200 and 250 kg ha-1 and B aplication (0 and 3 kg ha-1 on yield and hollow stem disorder of the cauliflower ‘Júlia’ cultivated in Kandiustalf at Tietê region, São Paulo State, Brazil. The curd diameter was not influenced by treatments and corresponding mean value was 17.74 cm. Nitrogen levels

  19. Coincidence of flowering time and the productivity and quality of cauliflower hybrid seeds Coincidência de florescimento entre linhagens de couve-flor na produtividade e qualidade de sementes híbridas

    Directory of Open Access Journals (Sweden)

    Marcelo Fontanetti Verdial

    2001-09-01

    Full Text Available The missing of flowering synchronization between the self-incompatible lines in a crop field of cauliflower hybrid seeds besides making the seed production smaller can compromise the genetic purity of them. The coincidence of the flowering time between two cauliflower lines was examined to study its effect on the productivity and quality of hybrid seeds. The treatments consisted of six different sowing dates, every fifteen days, using a self-incompatible tropical line pollinated by a winter line which does not present self-incompatibility. The following characteristics were evaluated: leaf average area and number of flowers per plant, number of siliques per plant, number and weight of seeds per plant, weight of thousand seeds and average number of seeds per silique. The germination standard test and genetic seed purity were determined for each treatment. The coincident flowering season between cauliflower lines affects directly the productivity and the genetic quality of the produced hybrid seeds. The closer the flowering time coincidence between the lines, the greater the number of seeds per silique and the smaller the percentage of non-hybrid seedlings. However, the coincidence of the flowering season between lines was found to influence physiological seed quality.A falta de sincronismo de florescimento entre as linhagens auto incompatíveis em um campo de produção de sementes híbridas de couve flor pode além de reduzir a produção de sementes comprometer a pureza genética das mesmas. Com o objetivo de estudar o efeito da coincidência de florescimento entre linhagens de couve-flor na produtividade e qualidade de sementes híbridas, foi realizado o presente experimento. Os tratamentos consistiram em seis diferentes épocas de semeadura, espaçadas a cada quinze dias, de uma linhagem de verão auto-incompatível que foi polinizada por uma linhagem de inverno que não apresenta auto-incompatibilidade. Observou-se a coincidência do

  20. Reporte de nuevo cultivar. DOGO, NUEVO CULTIVAR CUBANO DE FLOR DE JAMAICA (Hibiscus sabdariffa, L OBTENIDO POR INDUCCIÓN DE MUTACIONES CON RAYOS GAMMA 60 CO

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    María C. González Cepero

    2015-01-01

    Full Text Available En el Instituto Nacional de Ciencias Agrícolas se obtuvo un nuevo cultivar de Flor de Jamaica mediante el empleo de inducción de mutaciones. Difiere de la variedad donante en el ciclo, número de frutos por planta, peso de los frutos y forma de las hojas

  1. Reporte de nuevo cultivar. DOGO, NUEVO CULTIVAR CUBANO DE FLOR DE JAMAICA (Hibiscus sabdariffa, L) OBTENIDO POR INDUCCIÓN DE MUTACIONES CON RAYOS GAMMA 60 CO

    OpenAIRE

    María C. González Cepero

    2015-01-01

    En el Instituto Nacional de Ciencias Agrícolas se obtuvo un nuevo cultivar de Flor de Jamaica mediante el empleo de inducción de mutaciones. Difiere de la variedad donante en el ciclo, número de frutos por planta, peso de los frutos y forma de las hojas

  2. BENITO, NUEVO MUTANTE DE FLOR DE JAMAICA (Hibiscus sabdariffa, L. DE ALTO POTENCIAL PRODUCTIVO EN CONDICIONES DE BAJOS SUMINISTROS DE AGUA

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    María C. González Cepero

    2015-01-01

    Full Text Available En el Instituto Nacional de Ciencias Agrícolasse desarrolló un programa de mejoramiento genético dirigidoa obtener variedades de Flor de Jamaica de alto potencialproductivo, en condiciones de bajos suministros de agua.

  3. Finitary Spacetime Sheaves of Quantum Causal Sets Curving Quantum Causality

    CERN Document Server

    Mallios, A

    2001-01-01

    A locally finite, causal and quantal substitute for a locally Minkowskian principal fiber bundle $\\cal{P}$ of modules of Cartan differential forms $\\omg$ over a bounded region $X$ of a curved $C^{\\infty}$-smooth differential manifold spacetime $M$ with structure group ${\\bf G}$ that of orthochronous Lorentz transformations $L^{+}:=SO(1,3)^{\\uparrow}$, is presented. ${\\cal{P}}$ is the structure on which classical Lorentzian gravity, regarded as a Yang-Mills type of gauge theory of a $sl(2,\\com)$-valued connection 1-form $\\cal{A}$, is usually formulated. The mathematical structure employed to model this replacement of ${\\cal{P}}$ is a principal finitary spacetime sheaf $\\vec{\\cal{P}}_{n}$ of quantum causal sets $\\amg_{n}$ with structure group ${\\bf G}_{n}$, which is a finitary version of the group ${\\bf G}$ of local symmetries of General Relativity, and a finitary Lie algebra ${\\bf g}_{n}$-valued connection 1-form ${\\cal{A}}_{n}$ on it, which is a section of its sub-sheaf $\\amg^{1}_{n}$. ${\\cal{A}}_{n}$ is phys...

  4. The Impossibility of Causality Testing

    OpenAIRE

    Conway, Roger K.; P. A. V. B. Swamy; Yanagida, John F.; Muehlen, Peter von zur

    1984-01-01

    Causality tests developed by Sims and Granger are fatally flawed for several reasons First, when two variables, X and Y, are uncorrelated, X has no linear predictive value for Y, but X,and Y may be nonlinearly related unless they are statistically Independent, In which case X and Y are not related at all The light-hand side variables In a regression equation are exogenous If they are mean Independent of the disturbance term Mean Independence IS stronger than uncorrelatedness The proofs for de...

  5. Breaking the arrows of causality

    DEFF Research Database (Denmark)

    Valsiner, Jaan

    2014-01-01

    Theoretical models of catalysis have proven to bring with them major breakthroughs in chemistry and biology, from the 1830s onward. It can be argued that the scientific status of chemistry has become established through the move from causal to catalytic models. Likewise, the central explanatory...... role of cyclical models in biology has made it possible to move from the idea of genetic determination to that of epigenetic negotiation as the core of biological theory. In psychology, catalytic thinking has been outside of the realm of accepted scientific schemes, as the axiomatic dependence upon the...

  6. The Functions of Danish Causal Conjunctions

    Directory of Open Access Journals (Sweden)

    Rita Therkelsen

    2004-01-01

    Full Text Available In the article I propose an analysis of the Danish causal conjunctions fordi, siden and for based on the framework of Danish Functional Grammar. As conjunctions they relate two clauses, and their semantics have in common that it indicates a causal relationship between the clauses. The causal conjunctions are different as far as their distribution is concerned; siden conjoins a subordinate clause and a main clause, for conjoins two main clauses, and fordi is able to do both. Methodologically I have based my analysis on these distributional properties comparing siden and fordi conjoining a subordinate and a main clause, and comparing for and fordi conjoining two main clauses, following the thesis that they would establish a causal relationship between different kinds of content. My main findings are that fordi establishes a causal relationship between the events referred to by the two clauses, and the whole utterance functions as a statement of this causal relationship. Siden presupposes such a general causal relationship between the two events and puts forward the causing event as a reason for assuming or wishing or ordering the caused event, siden thus establishes a causal relationship between an event and a speech act. For equally presupposes a general causal relationship between two events and it establishes a causal relationship between speech acts, and fordi conjoining two main clauses is able to do this too, but in this position it also maintains its event-relating ability, the interpretation depending on contextual factors.

  7. Space and time in perceptual causality

    Directory of Open Access Journals (Sweden)

    Benjamin Straube

    2010-04-01

    Full Text Available Inferring causality is a fundamental feature of human cognition that allows us to theorize about and predict future states of the world. Michotte suggested that humans automatically perceive causality based on certain perceptual features of events. However, individual differences in judgments of perceptual causality cast doubt on Michotte’s view. To gain insights in the neural basis of individual difference in the perception of causality, our participants judged causal relationships in animations of a blue ball colliding with a red ball (a launching event while fMRI-data were acquired. Spatial continuity and temporal contiguity were varied parametrically in these stimuli. We did not find consistent brain activation differences between trials judged as caused and those judged as non-caused, making it unlikely that humans have universal instantiation of perceptual causality in the brain. However, participants were slower to respond to and showed greater neural activity for violations of causality, suggesting that humans are biased to expect causal relationships when moving objects appear to interact. Our participants demonstrated considerable individual differences in their sensitivity to spatial and temporal characteristics in perceiving causality. These qualitative differences in sensitivity to time or space in perceiving causality were instantiated in individual differences in activation of the left basal ganglia or right parietal lobe, respectively. Thus, the perception that the movement of one object causes the movement of another is triggered by elemental spatial and temporal sensitivities, which themselves are instantiated in specific distinct neural networks.

  8. Flower morpho-anatomy in Epiphyllum phyllanthus (Cactaceae Morfo-anatomía de la flor de Epiphyllum phyllanthus (Cactaceae

    Directory of Open Access Journals (Sweden)

    Odair José Garcia de Almeida

    2010-04-01

    Full Text Available The aim of this contribution was to analyze the morpho-anatomical floral structure of Epiphyllum phyllanthus (L. Haw., a widely distributed species across South America, occurring in humid forests as an epiphyte. Flowers and flower buds were collected in Maringá, Paraná State, Brazil, fixed, processed, and analyzed under light microscope and scanning electron microscope. The flower is sessile and epigynous with a well-developed hypanthium. All flower whorls have uniseriate epidermis. Secretory cavities containing mucilage and calcium oxalate crystals occur throughout the floral parenchymatous tissue. The androecium has many stamens with tetrasporangiate and bithecal anthers. The wall of the young anther is formed by epidermis, endothecium, a middle layer, and binucleate secretory tapetum that eventually becomes uninucleate. The gynoecium is syncarpous with 9-10 carpels, pluriovulate, and with parietal placentation. The ovary has inverted vascular bundles in a similar pattern as in Pereskia. The nectariferous region occurs on the inner surface of the hypanthium. The stigma has 9-10 lobes with a secretory epidermis. The ovules are circinotropous, bitegmic, crassinucelate, and have long funiculus as in many other Cactaceae.El objetivo de esta investigación fue analizar la morfo-anatomía de la flor de Epiphyllum phyllanthus (L. Haw, especie con distribución amplia en los bosques húmedos de América del Sur como epífita. Se recolectaron flores y botones en Maringá, PR, Brasil, fijados, procesados y analizados con microscopio de luz y con microscopio electrónico de barrido. La flor es sésil, epígina con hipanto desarrollado. Todos los verticilos florales presentan epidermis simple. Cavidades secretoras con mucilago y cristales de oxalato de calcio se encuentran en todo el tejido parenquimático de la flor. El androceo posee muchos estambres, con anteras bitecas y tetraesporangiadas. La pared de la antera joven está formada por epidermis

  9. Probabilistic causality and radiogenic cancers

    International Nuclear Information System (INIS)

    A review and scrutiny of the literature on probability and probabilistic causality shows that it is possible under certain assumptions to estimate the probability that a certain type of cancer diagnosed in an individual exposed to radiation prior to diagnosis was caused by this exposure. Diagnosis of this causal relationship like diagnosis of any disease - malignant or not - requires always some subjective judgments by the diagnostician. It is, therefore, illusory to believe that tables based on actuarial data can provide objective estimates of the chance that a cancer diagnosed in an individual is radiogenic. It is argued that such tables can only provide a base from which the diagnostician(s) deviate in one direction or the other according to his (their) individual (consensual) judgment. Acceptance of a physician's diagnostic judgment by patients is commonplace. Similar widespread acceptance of expert judgment by claimants in radiation compensation cases does presently not exist. Judicious use of the present radioepidemiological tables prepared by the Working Group of the National Institutes of Health or of updated future versions of similar tables may improve the situation. 20 references

  10. Estudo florístico do componente herbáceo e relação com solos em áreas de caatinga do embasamento cristalino e bacia sedimentar, Petrolândia, PE, Brasil Herbaceous floristic study and relationship with soil of crystalline shield and sedimentary basin caatinga areas at Petrolândia, Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    Kleber Andrade da Silva

    2009-03-01

    Full Text Available Realizou-se um levantamento florístico em áreas de caatinga do embasamento cristalino e de bacia sedimentar, em Petrolândia, Pernambuco, objetivando-se identificar diferenças na composição, hábito e forma de vida das herbáceas entre as duas áreas. Foram coletadas amostras de solo nas profundidades de 0 a 20 cm e de 20 a 40 cm. Foram estabelecidas 100 parcelas de 1×1 m em cada área e coletadas todas as espécies herbáceas. De modo geral, o solo da área do embasamento cristalino foi mais fértil, raso, com maior capacidade de reter água e maior porcentagem de argila. Os números de famílias, gêneros e espécies das áreas da bacia sedimentar e do embasamento cristalino foram 32, 62 e 78 e 31, 53 e 69, respectivamente. A similaridade florística entre as áreas foi alta (75%. A análise de agrupamento mostrou que os arranjos florísticos entre as parcelas amostradas são mais semelhantes dentro de cada área que entre áreas, sugerindo a existência de grupos distintos. Tipo de solo parece não ser um fator decisivo na similaridade florística, hábito e proporção de forma de vida das herbáceas da vegetação da caatinga quando as áreas são próximas, mas pode influenciar a ocorrência e a freqüência de algumas espécies.Floristic surveys were carried out in two close caatinga areas, one on the crystalline shield and the other on a sedimentary basin, both at Petrolândia, Pernambuco, Brazil, with the objective of identifying differences between the two areas in composition, habit and life form of the herbaceous flora. One hundred 1×1 m plots were established in each area and all the herbaceous species were identified. Soil samples were collected at 0-20 and 20-40 cm depths. In general, the soil in the crystalline shield area was shallower, had greater clay content, with higher water holding capacity, and was more fertile. The number of families, genera and species in the sedimentary basin and crystalline shield areas were 32

  11. Comparação florística e estrutural de duas florestas de várzea no estuário amazônico, Pará, Brasil

    Directory of Open Access Journals (Sweden)

    Fábio de Jesus Batista

    2011-04-01

    Full Text Available O objetivo deste trabalho foi conhecer e comparar a composição florística e a estrutura de duas áreas de florestas de várzea localizadas na reserva extrativista Chocoaré-Mato Grosso, Santarém Novo-PA. O inventário florístico abrangeu 1,5 ha em parcelas de 10 x 100 m, distribuídas na área 1 (1,0 ha e área 2 (0,5 ha. Foram identificados os indivíduos arbóreos com circunferência a 1,3 m altura do solo (CAP > 30 cm e demonstrada a riqueza, área basal e o IVI (Índice de Valor de Importância para cada área. A relação entre as áreas foi realizada por meio da similaridade de espécies, densidade, área basal, análise de agrupamento e espécies indicadoras. Na área 1, ocorreram 613 ind.ha-1 (26,67 m².ha-1 distribuídos em 17 famílias, 33 gêneros e 34 espécies com Euterpe oleracea, Enterolobium maximum, Symphonia globulifera, Pterocarpus amazonicus e Virola surinamensis apresentando os maiores IVI's e a área 2 com 744 ind.ha-1 (35,34 m².ha-1 em 13 famílias, 24 gêneros e 26 espécies com Mauritia flexuosa, Euterpe oleracea, Virola surinamensis, Tapirira guianensis e Inga thibaudiana com os maiores IVI's. As áreas registraram baixas similaridades entre si (0,18 e tanto a densidade quanto a área basal foram superiores na área 2. O agrupamento separou as áreas entre si e das 51 espécies, apenas 15 foram indicadoras. Conclui-se que, as florestas apresentaram baixa riqueza com pouca semelhança entre as populações arbóreas e as espécies indicadoras ocorreram nas áreas 1 e 2.

  12. Causal relationship: a new tool for the causal characterization of Lorentzian manifolds

    International Nuclear Information System (INIS)

    We define and study a new kind of relation between two diffeomorphic Lorentzian manifolds called a causal relation, which is any diffeomorphism characterized by mapping every causal vector of the first manifold onto a causal vector of the second. We perform a thorough study of the mathematical properties of causal relations and prove in particular that two given Lorentzian manifolds (say V and W) may be causally related only in one direction (say from V to W, but not from W to V). This leads us to the concept of causally equivalent (or isocausal in short) Lorentzian manifolds as those mutually causally related and to a definition of causal structure over a differentiable manifold as the equivalence class formed by isocausal Lorentzian metrics upon it. Isocausality is a more general concept than the conformal relationship, because we prove the remarkable result that a conformal relation φ is characterized by the fact of being a causal relation of the particular kind in which both φ and φ-1 are causal relations. Isocausal Lorentzian manifolds are mutually causally compatible, they share some important causal properties, and there are one-to-one correspondences, which are sometimes non-trivial, between several classes of their respective future (and past) objects. A more important feature is that they satisfy the same standard causality constraints. We also introduce a partial order for the equivalence classes of isocausal Lorentzian manifolds providing a classification of all the causal structures that a given fixed manifold can have. By introducing the concept of causal extension we put forward a new definition of causal boundary for Lorentzian manifolds based on the concept of isocausality, and thereby we generalize the traditional Penrose constructions of conformal infinity, diagrams and embeddings. In particular, the concept of causal diagram is given. Many explicit clarifying examples are presented throughout the paper

  13. FDI and growth: a causal relationship

    OpenAIRE

    Chowdhury, Abdur; Mavrotas, George

    2005-01-01

    The paper examines the causal relationship between FDI and economic growth by using an innovative econometric methodology to study the direction of causality between the two variables. We apply our methodology, based on the Toda-Yamamoto test for causality, to time-series data covering the period 1969-2000 for three developing countries, namely Chile, Malaysia and Thailand, all of them major recipients of FDI with a different history of macroeconomic episodes, policy regimes and growth patter...

  14. Linear causal modeling with structural equations

    CERN Document Server

    Mulaik, Stanley A

    2009-01-01

    Emphasizing causation as a functional relationship between variables that describe objects, Linear Causal Modeling with Structural Equations integrates a general philosophical theory of causation with structural equation modeling (SEM) that concerns the special case of linear causal relations. In addition to describing how the functional relation concept may be generalized to treat probabilistic causation, the book reviews historical treatments of causation and explores recent developments in experimental psychology on studies of the perception of causation. It looks at how to perceive causal

  15. The problem of causality in cultivation research

    OpenAIRE

    Rossmann, Constanze; Brosius, Hans-Bernd

    2004-01-01

    This paper offers an up-to-date review of problems in determining causal relationships in cultivation research, and considers the research rationales of various approaches with special reference to causal interpretation. It describes in turn a number of methodologies for addressing the problem and resolving it as far as this is possible. The issue of causal inference arises not only in cultivation research, however, but is basic to all media effects theories and approaches primarily at the ma...

  16. Causal inference in economics and marketing.

    Science.gov (United States)

    Varian, Hal R

    2016-07-01

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual-a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference. PMID:27382144

  17. Causal inference in economics and marketing

    Science.gov (United States)

    Varian, Hal R.

    2016-01-01

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual—a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference. PMID:27382144

  18. La flor de mi secreto (Almodóvar, 1995: La literatura como seducción

    Directory of Open Access Journals (Sweden)

    Martínez-Carazo, Cristina

    2011-04-01

    Full Text Available The multiple references to writing in Pedro Almodovar’s La flor de mi secreto (1995 have arguably made this film his most literary. Reading and writing function as the structural axis of the movie because they define the existence of the main character - Leo/Amanda Gris. But beyond the constant literary allusions, what makes the “literarity” of this film is, on the one hand, the construction of the protagonist according to literary models and on the other the exploration of her subjectivity through her writing. Leo as a character is created as a replica of the tormented writers that she admires. In their stereotypical tradition, she is an alcoholic, addicted to sleeping pills, suicidal, obsessed with her loneliness and installed in her writing as a survival space. Furthermore, the spectator accesses her subjectivity through her career as a writer because her melodramatic life gets entangled with her novels. Almodóvar projects his literary ghosts in La flor de mi secreto and in the process, subverts the parameters of literature, the canon, the gender and genre categories and the question of authorship. He also resists a stable definition of literature as art by inserting it in a filmic text, favoring a complex intertextuality which contributes to dissolving the frontiers between high and low culture and to opening a common ground for the arts.Las múltiples referencias a la escritura presentes en La flor de mi secreto (1995 han llevado a etiquetar esta película como la más literaria de Pedro Almodóvar. La lectura y la escritura funcionan como hilo conductor de la película en la medida en que articulan la existencia de la protagonista, Leo/Amanda Gris. Pero más allá de este despliegue de alusiones literarias, lo que en realidad determina la literaridad del film es, por un lado, la construcción de dicho personaje a partir de modelos literarios y por otro la exploración de su subjetividad a partir de la escritura. Leo se perfila como

  19. Heterogeneous Causal Effects and Sample Selection Bias

    DEFF Research Database (Denmark)

    Breen, Richard; Choi, Seongsoo; Holm, Anders

    2015-01-01

    The role of education in the process of socioeconomic attainment is a topic of long standing interest to sociologists and economists. Recently there has been growing interest not only in estimating the average causal effect of education on outcomes such as earnings, but also in estimating how...... causal effects might vary over individuals or groups. In this paper we point out one of the under-appreciated hazards of seeking to estimate heterogeneous causal effects: conventional selection bias (that is, selection on baseline differences) can easily be mistaken for heterogeneity of causal effects...

  20. Causal ubiquity in quantum physics. A superluminal and local-causal physical ontology

    Energy Technology Data Exchange (ETDEWEB)

    Neelamkavil, Raphael

    2014-07-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly [non-causal] processes, something exists processually in extension-motion, between the causal and the [non-causal]. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That is, the QM world is sub-luminally, luminally and superluminally local-causal throughout, and the Law of Causality is ubiquitous in the micro-world. Thus, ''probabilistic causality'' is a merely epistemic term.

  1. Causal ubiquity in quantum physics. A superluminal and local-causal physical ontology

    International Nuclear Information System (INIS)

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly [non-causal] processes, something exists processually in extension-motion, between the causal and the [non-causal]. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That is, the QM world is sub-luminally, luminally and superluminally local-causal throughout, and the Law of Causality is ubiquitous in the micro-world. Thus, ''probabilistic causality'' is a merely epistemic term.

  2. Qualidade pós-colheita de couve-flor ‘Teresópolis gigante' tratada com etileno, absorvedor de etileno e 1-metilciclopropeno Postharvest quality of ‘Teresópolis gigante' cauliflower treated with ethylene, ethylene absorbent and 1-methylcyclopropene

    Directory of Open Access Journals (Sweden)

    Auri Brackmann

    2005-12-01

    Full Text Available O objetivo deste trabalho foi de avaliar o efeito da aplicação e absorção de etileno, assim como o uso de 1-metilciclopropeno (1-MCP sobre a qualidade pós-colheita de couve-flor ‘Teresópolis Gigante'. Os tratamentos utilizados foram: armazenamento refrigerado, uso de saches de permanganato de potássio (80g, 1-MCP (1,0 e 0,5µl L-1 e aplicação de etileno (1,0µl L-1. De acordo com os resultados obtidos, a coloração mais verde da cabeça e das folhas foi obtida nos tratamentos com a aplicação de 1-MCP e uso de saches de permanganato de potássio. A menor firmeza da haste foi obtida com a aplicação de etileno. Conclui-se que a aplicação de 1-MCP, assim como o uso de saches de permanganato de potássio promovem a manutenção da cor verde da cabeça e das folhas, assim como o etileno exógeno reduz a firmeza da haste de couve-flor ‘Teresópolis Gigante'.The objective of this work was to analyze the effect of the application and absorption of ethylene, as well as the use of 1-methylcyclopropene (1-MCP concerning the postharvest quality of ‘Teresópolis Gigante' cauliflower. According to the results, the greenest value of the head and of the leaf were got in treatments with application of 1-MCP and use of potassium permanganate. The least stem's firmness was got with the application of ethylene. Then the application of 1-MCP, as well as the use potassium permanganate promoted the maintenance of the green color of the head and of the leaf, as well as exogenous ethylene reduced the stem's firmness of the ‘Teresópolis Gigante' cauliflower.

  3. Quantum retrodiction and causality principle

    International Nuclear Information System (INIS)

    Quantum mechanics is factually a predictive science. But quantum retrodiction may also be needed, e.g., for the experimental verification of the validity of the Schroedinger equation for the wave function in the past if the present state is given. It is shown that in the retrodictive analog of the prediction the measurement must be replaced by another physical process called the retromeasurement. In this process, the reduction of a state vector into eigenvectors of a measured observable must proceed in the opposite direction of time as compared to the usual reduction. Examples of such processes are unknown. Moreover, they are shown to be forbidden by the causality principle stating that the later event cannot influence the earlier one. So quantum retrodiction seems to be unrealizable. It is demonstrated that the approach to the retrodiction given by S.Watanabe and F.Belinfante must be considered as an unsatisfactory ersatz of retrodicting. 20 refs., 3 figs

  4. Comparison theorems for causal diamonds

    CERN Document Server

    Berthiere, Clement; Solodukhin, Sergey N

    2015-01-01

    We formulate certain inequalities for the geometric quantities characterizing causal diamonds in curved and Minkowski spacetimes. These inequalities involve the red-shift factor which, as we show explicitly in the spherically symmetric case, is monotonic in the radial direction and it takes its maximal value at the centre. As a byproduct of our discussion we re-derive Bishop's inequality without assuming the positivity of the spatial Ricci tensor. We then generalize our considerations to arbitrary, static and not necessarily spherically symmetric, asymptotically flat spacetimes. In the case of spacetimes with a horizon our generalization involves the so-called {\\it domain of dependence}. The respective volume, expressed in terms of the duration measured by a distant observer compared with the volume of the domain in Minkowski spacetime, exhibits behaviours which differ if $d=4$ or $d>4$. This peculiarity of four dimensions is due to the logarithmic subleading term in the asymptotic expansion of the metric nea...

  5. The Power of Causal Beliefs and Conflicting Evidence on Causal Judgments and Decision Making

    Science.gov (United States)

    Garcia-Retamero, Rocio; Muller, Stephanie M.; Catena, Andres; Maldonado, Antonio

    2009-01-01

    In two experiments, we investigated the relative impact of causal beliefs and empirical evidence on both decision making and causal judgments, and whether this relative impact could be altered by previous experience. 2. Selected groups of participants in both experiments received pre-training with either causal or neutral cues, or no pre-training…

  6. Spin foam models as energetic causal sets

    Science.gov (United States)

    Cortês, Marina; Smolin, Lee

    2016-04-01

    Energetic causal sets are causal sets endowed by a flow of energy-momentum between causally related events. These incorporate a novel mechanism for the emergence of space-time from causal relations [M. Cortês and L. Smolin, Phys. Rev. D 90, 084007 (2014); Phys. Rev. D 90, 044035 (2014)]. Here we construct a spin foam model which is also an energetic causal set model. This model is closely related to the model introduced in parallel by Wolfgang Wieland in [Classical Quantum Gravity 32, 015016 (2015)]. What makes a spin foam model also an energetic causal set is Wieland's identification of new degrees of freedom analogous to momenta, conserved at events (or four-simplices), whose norms are not mass, but the volume of tetrahedra. This realizes the torsion constraints, which are missing in previous spin foam models, and are needed to relate the connection dynamics to those of the metric, as in general relativity. This identification makes it possible to apply the new mechanism for the emergence of space-time to a spin foam model. Our formulation also makes use of Markopoulou's causal formulation of spin foams [arXiv:gr-qc/9704013]. These are generated by evolving spin networks with dual Pachner moves. This endows the spin foam history with causal structure given by a partial ordering of the events which are dual to four-simplices.

  7. Controlling for causally relevant third variables.

    Science.gov (United States)

    Goodie, Adam S; Williams, Cristina C; Crooks, C L

    2003-10-01

    In 3 experiments, the authors tested the conditions under which 3rd variables are controlled for in making causal judgments. The authors hypothesized that 3rd variables are controlled for when the 3rd variables are themselves perceived as causal. In Experiment 1, the participants predicted test performance after seeing information about wearing a lucky garment, taking a test-preparation course, and staying up late. The course (perceived as more causally relevant) was controlled for more than was the garment (perceived as less causally relevant) in assessing the effectiveness of staying up late. In Experiments 2 and 3, to obviate the many alternative accounts that arise from the realistic cover story of Experiment 1, participants predicted flowers' blooming after the presentation or nonpresentation of liquids. When one liquid was trained as causal, it was controlled for more in judging another liquid than when it was trained as neutral. Overall, stimuli perceived as causal were controlled for more when judging other stimuli. The authors concluded that the effect of perceived causal relevance on causal conditionalizing is real and normatively reasonable. PMID:14672103

  8. Causal processes and propensities in quantum mechanics

    Directory of Open Access Journals (Sweden)

    Mauricio SUÁREZ

    2010-01-01

    Full Text Available I offer an alternative interpretation of Van Fraassen's influential arguments against causal realism in quantum mechanics. These arguments provide in fact a good guide to the different causal models available for the Einstein-Podolsky-Rosen correlations, which in turn shed light on the nature of quantum propensities.

  9. Compact Representations of Extended Causal Models

    Science.gov (United States)

    Halpern, Joseph Y.; Hitchcock, Christopher

    2013-01-01

    Judea Pearl (2000) was the first to propose a definition of actual causation using causal models. A number of authors have suggested that an adequate account of actual causation must appeal not only to causal structure but also to considerations of "normality." In Halpern and Hitchcock (2011), we offer a definition of actual causation…

  10. mediation: R Package for Causal Mediation Analysis

    Directory of Open Access Journals (Sweden)

    Dustin Tingley

    2014-09-01

    Full Text Available In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting such an analysis. The package is organized into two distinct approaches. Using the model-based approach, researchers can estimate causal mediation effects and conduct sensitivity analysis under the standard research design. Furthermore, the design-based approach provides several analysis tools that are applicable under different experimental designs. This approach requires weaker assumptions than the model-based approach. We also implement a statistical method for dealing with multiple (causally dependent mediators, which are often encountered in practice. Finally, the package also offers a methodology for assessing causal mediation in the presence of treatment noncompliance, a common problem in randomized trials.

  11. Causalities of the Taiwan Stock Market

    OpenAIRE

    Juhi-Lian Julian Ting

    2003-01-01

    Volatility, fitting with first order Landau expansion, stationarity, and causality of the Taiwan stock market (TAIEX) are investigated based on daily records. Instead of consensuses that consider stock market index change as a random time series we propose the market change as a dual time series consists of the index and the corresponding volume. Therefore, causalities between these two time series are investigated.

  12. Campbell's and Rubin's Perspectives on Causal Inference

    Science.gov (United States)

    West, Stephen G.; Thoemmes, Felix

    2010-01-01

    Donald Campbell's approach to causal inference (D. T. Campbell, 1957; W. R. Shadish, T. D. Cook, & D. T. Campbell, 2002) is widely used in psychology and education, whereas Donald Rubin's causal model (P. W. Holland, 1986; D. B. Rubin, 1974, 2005) is widely used in economics, statistics, medicine, and public health. Campbell's approach focuses on…

  13. Unpacking the causal chain of financial literacy

    OpenAIRE

    Carpena, Fenella; Cole, Shawn; Shapiro, Jeremy; Zia, Bilal

    2011-01-01

    A growing body of literature examines the causal impact of financial literacy on individual, household, and firm level outcomes. This paper unpacks the mechanism of impact by focusing on the first link in the causal chain. Specifically, it studies the experimental impact of financial literacy on three distinct dimensions of financial knowledge. The analysis finds that financial literacy do...

  14. Causal random geometry from stochastic quantization

    DEFF Research Database (Denmark)

    Ambjørn, Jan; Loll, R.; Westra, W.; Zohren, S.

    2010-01-01

     in this short note we review a recently found formulation of two-dimensional causal quantum gravity defined through Causal Dynamical Triangulations and stochastic quantization. This procedure enables one to extract the nonperturbative quantum Hamiltonian of the random surface model including the...

  15. Levantamento das pastagens naturais da região de Santa Maria-RS, Brasil

    Directory of Open Access Journals (Sweden)

    Quadros Fernando Luiz Ferreira de

    2003-01-01

    Full Text Available Este trabalho foi realizado com o intuito de se obter um levantamento das pastagens naturais da região de Santa Maria, a qual foi subdividida, para este objetivo, em quatro localidades: Dilermando de Aguiar, Pains, Santa Flora e São Martinho. O levantamento utilizou estimativas visuais da freqüência de espécies através do método BOTANAL e permitiu a identificação de 61 espécies, dentre as quais 45 apresentaram contribuição significativa para a biomassa aérea da vegetação. No distrito de Pains, encontrou-se maior freqüência das espécies Axonopus affinis, Eragrostis plana, Desmodium barbatum e Aristida spp.. Em Dilermando de Aguiar, houve maior contribuição de Calamagrostis viridiflavescens, Schizachyrium microstachyum e Paspalum notatum a qual foi, também, uma espécie abundante em Santa Flora, assim como Desmodium incanum. As espécies mais freqüentes em São Martinho foram: Baccharis trimera, Paspalum plicatulum e Erianthus angustifolius. O teste de aleatorização mostrou que, em todas as localidades, ocorreu diferença significativa na sua composição florística (P= 0,0058, evidenciando a inexistência de associação entre os tipos fisionômico-florísticos e os tipos de solo. A partir disto, este levantamento permite que se estabeleçam prioridades quanto à pesquisa e manejo das pastagens naturais dos diferentes grupos fisionômico-florísticos da região.

  16. Granger causality in wall-bounded turbulence

    International Nuclear Information System (INIS)

    Granger causality is based on the idea that if a variable helps to predict another one, then they are probably involved in a causality relationship. This technique is based on the identification of a predictive model for causality detection. The aim of this paper is to use Granger causality to study the dynamics and the energy redistribution between scales and components in wall-bounded turbulent flows. In order to apply it on flows, Granger causality is generalized for snapshot-based observations of large size using linear-model identification methods coming from model reduction. Optimized DMD, a variant of the Dynamic Mode Decomposition, is considered for building a linear model based on snapshots. This method is used to link physical events and extract physical mechanisms associated to the bursting process in the logarithmic layer of a turbulent channel flow.

  17. Quantum-coherent mixtures of causal relations

    CERN Document Server

    MacLean, Jean-Philippe W; Spekkens, Robert W; Resch, Kevin J

    2016-01-01

    Understanding the causal influences that hold among the parts of a system is critical both to explaining that system's natural behaviour and to controlling it through targeted interventions. In a quantum world, understanding causal relations is equally important, but the set of possibilities is far richer. The two basic ways in which a pair of time-ordered quantum systems may be causally related are by a cause-effect mechanism or by a common cause acting on both. Here, we show that it is possible to have a coherent mixture of these two possibilities. We realize such a nonclassical causal relation in a quantum optics experiment and derive a set of criteria for witnessing the coherence based on a quantum version of Berkson's paradox. The interplay of causality and quantum theory lies at the heart of challenging foundational puzzles, such as Bell's theorem and the search for quantum gravity, but could also provide a resource for novel quantum technologies.

  18. Causal ubiquity in quantum physics a superluminal and local-causal physical ontology

    CERN Document Server

    Neelamkavil, Raphael

    2014-01-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly non-causal processes, something exists processually in extension-motion, between the causal and the non-causal. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That

  19. Rendimiento y reacción a enfermedades en frijol tipo Flor de Mayo en riego y temporal Seed yield and disease reaction in Flor de Mayo bean type grown under irrigation and rainfed conditions

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Acosta Gallegos

    Full Text Available El frijol tipo Flor de Mayo es de alta demanda entre los consumidores del centro de México, su producción se realiza en las regiones de la Mesa Central, El Bajío y Semiárida. El objetivo fue determinar el rendimiento, peso de la semilla y reacción a enfermedades de un grupo de 14 líneas y dos testigos a través de 14 ambientes, 10 de temporal y cuatro de riego. Los ensayos se condujeron durante los ciclos primavera-verano 2008 y otoño-invierno 2008-2009. Se realizaron análisis de conjunto y por ensayos de temporal y de riego en forma independiente. Diferentes enfermedades atacaron al cultivo a través de los sitios de prueba; bajo temporal, las de mayor distribución fueron la bacteriosis común (Xanthomonas campestris pv phaseoli y la mancha angular (Phaeoisariopsis griseola; mientras que la antracnosis (Colletotrichum lindemuthianum y el mildiú velloso (Phythohpthora phaseoli mostraron un fuerte ataque en Calera, Zacatecas y Celaya, Guanajuato, respectivamente. El ambiente de mayor rendimiento promedio fue Celaya bajo riego (4.15 t ha-1 y el menor se obtuvo en Texcoco bajo temporal (0.90 t ha-1. El análisis conjunto detecto diferencias significativas (pThe 'Flor de Mayo' bean type is highly demanded by consumers in Central Mexico, its production takes place at the semiarid, El Bajio and the central plateau regions. The aim was to test a set of 14 bred lines plus two checks across 10 rainfed locations and four irrigated sites on the basis of seed yield, 100-seeds weight and disease reaction. Trials were conducted in the spring-summer season 2008 and fall-winter season 2008-2009. Data analyses were conducted including all test sites, and independently rainfed and irrigated sites. Different diseases attacked the crop across test sites; those widely distributed were common bacterial blight (Xanthomonas campestris pv phaseoli and angular leaf spot (Phaeoisariopsis griseola; whereas anthracnose (Colletotrichum lindemuthianum and downy

  20. Heterogeneidade florística das fitocenoses de restingas nos estados do Rio de Janeiro e Espírito Santo, Brasil

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Silva Magnago

    2011-04-01

    Full Text Available Esta pesquisa teve como objetivo comparar florísticamente as formações vegetacionais que compõe o ecossistema Restinga dos Estados do Rio de Janeiro e Espírito Santo. Para isto foi realizado uma compilação de dados de levantamentos florísticos e fitossociológicos, sendo utilizado para esta análise o índice de similaridade de Jaccard, onde as interpretações se deram pela média de grupo (UPGMA. As 11 formações analisadas apresentaram uma riqueza total de 990 espécies, distribuídas em 141 famílias, sendo Fabaceae (73, Myrtaceae (59, Rubiaceae (48, Orchidaceae (44, Cyperaceae (38, Poaceae (36, Bromeliaceae (35, Euphorbiaceae (30, Asteraceae (30 as de maior riqueza. A similaridade entre as formações foi baixa, sendo o maior valor de 33%. Os resultados obtidos denotam uma alta heterogeneidade florística existente nas formações que compõe o ecossistema Restinga nos dois Estados analisados, sendo esta determinada por diferentes fatores que atuam em cada fitocenose.

  1. Efeito de sanificantes no controle pós-colheita da podridão parda (Monilinia fructicola) e da podridão mole (Rhizopus stolonifer) em pêssegos Effect of sanitizing products on the postharvest control of brown rot (Monilinia fructicola) and soft rot (Rhizopus stolonifer) in peaches

    OpenAIRE

    Fabiana Marchi de Abreu; Silvia de Afonseca Lourenço; Eliane Bassetto; Fabrício Packer Gonçalves; Marise Cagnim Martins; Lilian Amorim

    2008-01-01

    O objetivo desse trabalho foi avaliar o efeito in vitro e in vivo dos sanificantes cloreto de benzalcônio (Fegatex®), biomassa cítrica (Ecolife40®) e ozônio no controle da podridão parda (Monilinia fructicola) e da podridão mole (Rhizopus stolonifer) em pêssegos das cultivares Aurora, Dourado e Flor da Prince. Cloreto de benzalcônio e biomassa cítrica, aplicados in vitro, ambos na concentração de 1000 mL L-1, inibiram totalmente o crescimento radial (micelial) de M. fructicola, porém nenhum d...

  2. Causal localizations in relativistic quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Castrigiano, Domenico P. L., E-mail: castrig@ma.tum.de; Leiseifer, Andreas D., E-mail: andreas.leiseifer@tum.de [Fakultät für Mathematik, TU München, Boltzmannstraße 3, 85747 Garching (Germany)

    2015-07-15

    Causal localizations describe the position of quantum systems moving not faster than light. They are constructed for the systems with finite spinor dimension. At the center of interest are the massive relativistic systems. For every positive mass, there is the sequence of Dirac tensor-localizations, which provides a complete set of inequivalent irreducible causal localizations. They obey the principle of special relativity and are fully Poincaré covariant. The boosters are determined by the causal position operator and the other Poincaré generators. The localization with minimal spinor dimension is the Dirac localization. Thus, the Dirac equation is derived here as a mere consequence of the principle of causality. Moreover, the higher tensor-localizations, not known so far, follow from Dirac’s localization by a simple construction. The probability of localization for positive energy states results to be described by causal positive operator valued (PO-) localizations, which are the traces of the causal localizations on the subspaces of positive energy. These causal Poincaré covariant PO-localizations for every irreducible massive relativistic system were, all the more, not known before. They are shown to be separated. Hence, the positive energy systems can be localized within every open region by a suitable preparation as accurately as desired. Finally, the attempt is made to provide an interpretation of the PO-localization operators within the frame of conventional quantum mechanics attributing an important role to the negative energy states.

  3. Mining Causality for Explanation Knowledge from Text

    Institute of Scientific and Technical Information of China (English)

    Chaveevan Pechsiri; Asanee Kawtrakul

    2007-01-01

    Mining causality is essential to provide a diagnosis. This research aims at extracting the causality existing within multiple sentences or EDUs (Elementary Discourse Unit). The research emphasizes the use of causality verbs because they make explicit in a certain way the consequent events of a cause, e.g., "Aphids suck the sap from rice leaves. Then leaves will shrink. Later, they will become yellow and dry.". A verb can also be the causal-verb link between cause and effect within EDU(s), e.g., "Aphids suck the sap from rice leaves causing leaves to be shrunk" ("causing" is equivalent to a causal-verb link in Thai). The research confronts two main problems: identifying the interesting causality events from documents and identifying their boundaries. Then, we propose mining on verbs by using two different machine learning techniques, Naive Bayes classifier and Support Vector Machine. The resulted mining rules will be used for the identification and the causality extraction of the multiple EDUs from text. Our multiple EDUs extraction shows 0.88 precision with 0.75 recall from Na'ive Bayes classifier and 0.89 precision with 0.76 recall from Support Vector Machine.

  4. Causal localizations in relativistic quantum mechanics

    International Nuclear Information System (INIS)

    Causal localizations describe the position of quantum systems moving not faster than light. They are constructed for the systems with finite spinor dimension. At the center of interest are the massive relativistic systems. For every positive mass, there is the sequence of Dirac tensor-localizations, which provides a complete set of inequivalent irreducible causal localizations. They obey the principle of special relativity and are fully Poincaré covariant. The boosters are determined by the causal position operator and the other Poincaré generators. The localization with minimal spinor dimension is the Dirac localization. Thus, the Dirac equation is derived here as a mere consequence of the principle of causality. Moreover, the higher tensor-localizations, not known so far, follow from Dirac’s localization by a simple construction. The probability of localization for positive energy states results to be described by causal positive operator valued (PO-) localizations, which are the traces of the causal localizations on the subspaces of positive energy. These causal Poincaré covariant PO-localizations for every irreducible massive relativistic system were, all the more, not known before. They are shown to be separated. Hence, the positive energy systems can be localized within every open region by a suitable preparation as accurately as desired. Finally, the attempt is made to provide an interpretation of the PO-localization operators within the frame of conventional quantum mechanics attributing an important role to the negative energy states

  5. ANÁLISE DOS DIFERENTES ESTÁDIOS DE DESENVOLVIMENTO DA CAATINGA EM SOBRAL, CEARÁ, BRASIL (ANALYSIS OF THE DIFFERENT STAGES OF CAATINGA VEGETATION DEVELOPMENT IN SOBRAL, CEARÁ, BRAZIL)

    OpenAIRE

    Pereira, Marízia; Braga, Petrónio; Guiomar, Nuno

    2014-01-01

    Resumo: O presente estudo teve como objetivo identificar a flora de várias etapas evolutivas da vegetação da caatinga alterada pela ação antrópica. Analisou-se a flora de 8 estações nos municípios de Sobral, Groaíras e Massapê na microrregião de Sobral no estado do Ceará, através de levantamentos florísticos realizados em março de 2014. Nas catenas de vegetação foram anotadas todas as árvores, arbustos, lianas e espécies herbáceas. O elenco florístico é composto por 178 espécies, distribuídas...

  6. Causality and momentum conservation from relative locality

    Science.gov (United States)

    Amelino-Camelia, Giovanni; Bianco, Stefano; Brighenti, Francesco; Buonocore, Riccardo Junior

    2015-04-01

    Theories involving curved momentum space, which recently became a topic of interest in the quantum-gravity literature, can, in general, violate many apparently robust aspects of our current description of the laws of physics, including relativistic invariance, locality, causality, and global momentum conservation. Here, we explore some aspects of the pathologies arising in generic theories involving curved momentum space for what concerns causality and momentum conservation. However, we also report results suggesting that when momentum space is maximally symmetric, and the theory is formulated relativistically, most notably including translational invariance with the associated relativity of spacetime locality, momentum is globally conserved and there is no violation of causality.

  7. Causal localizations in relativistic quantum mechanics

    International Nuclear Information System (INIS)

    Sufficient and necessary conditions for causal localizations of massive relativistic systems are developed. It is proven that the Dirac- and the Dirac tensor-system are up to unitary equivalence the only irreducible causal localizations with finite spinor dimension which have a massive relativistic extension. A formula for this extension is given. The existence of arbitrarily good localized states of positive energy is shown. In the context of the causality condition a Paley-Wiener theorem for bounded measurable matrix-valued functions is proven.

  8. The CMB in a Causal Set Universe

    CERN Document Server

    Zuntz, Joe

    2007-01-01

    We discuss Cosmic Microwave Background constraints on the causal set theory of quantum gravity, which has made testable predictions about the nature of dark energy. We flesh out previously discussed heuristic constraints by showing how the power spectrum of causal set dark energy fluctuations can be found from the overlap volumes of past light cones of points in the universe. Using a modified Boltzmann code we put constraints on the single parameter of the theory that are somewhat stronger than previous ones. We conclude that causal set theory cannot explain late-time acceleration without radical alterations to General Relativity.

  9. Causality in 3D Massive Gravity Theories

    CERN Document Server

    Edelstein, Jose D; Kilicarslan, Ercan; Leoni, Matias; Tekin, Bayram

    2016-01-01

    We study the constraints coming from local causality requirement in various 2+1 dimensional dynamical theories of gravity. In Topologically Massive Gravity, with a single parity noninvariant massive degree of freedom, and in New Massive Gravity, with two massive spin-$2$ degrees of freedom, causality and unitarity are compatible with each other and they both require the Newton's constant to be negative. In their extensions, such as the Born-Infeld gravity and the minimal massive gravity the situation is similar and quite different from their higher dimensional counterparts, such as quadratic (e.g., Einstein-Gauss-Bonnet) or cubic theories, where causality and unitarity are in conflict.

  10. Causality, Knowledge and Coordination in Distributed Systems

    CERN Document Server

    Ben-Zvi, Ido

    2011-01-01

    Effecting coordination across remote sites in a distributed system is an essential part of distributed computing, and also an inherent challenge. In 1978, an analysis of communication in asynchronous systems was suggested by Leslie Lamport. Lamport's analysis determines a notion of temporal precedence, a sort of weak notion of time, which is otherwise missing in asynchronous systems. This notion has been extensively utilized in various applications. Yet the analysis is limited to systems that are asynchronous. In this thesis we go beyond by investigating causality in synchronous systems. In such systems, the boundaries of causal influence are not charted out exclusively by message passing. Here time itself, passing at a uniform (or almost uniform) rate for all processes, is also a medium by which causal influence may fan out. This thesis studies, and characterizes, the combinations of time and message passing that govern causal influence in synchronous systems. It turns out that knowledge based analysis [FHMV...

  11. What becomes of a causal set

    CERN Document Server

    Wuthrich, Christian

    2015-01-01

    Unlike the relativity theory it seeks to replace, causal set theory has been interpreted to leave space for a substantive, though perhaps 'localized', form of 'becoming'. The possibility of fundamental becoming is nourished by the fact that the analogue of Stein's theorem from special relativity does not hold in causal set theory. Despite this, we find that in many ways, the debate concerning becoming parallels the well-rehearsed lines it follows in the domain of relativity. We present, however, some new twists and challenges. In particular, we show that a novel and exotic notion of becoming is compatible with causal sets. In contrast to the 'localized' becoming considered compatible with the dynamics of causal set theory by its advocates, our novel kind of becoming, while not answering to the typical A-theoretic demands, is 'global' and objective.

  12. Causality Between Urban Concentration and Environmental Quality

    Directory of Open Access Journals (Sweden)

    Amin Pujiati

    2015-08-01

    Full Text Available Population is concentrated in urban areas can cause the external diseconomies on environment if it exceeds the carrying capacity of the space and the urban economy. Otherwise the quality of the environment is getting better, led to the concentration of population in urban areas are increasingly high. This study aims to analyze the relationship of causality between the urban concentration and environmental quality in urban agglomeration areas. The data used in the study of secondary data obtained from the Central Bureau of statistics and the City Government from 2000 to 2013. The analytical method used is the Granger causality and descriptive. Granger causality study results showed no pattern of reciprocal causality, between urban concentration and the quality of the environment, but there unidirectional relationship between the urban concentration and environmental quality. This means that increasing urban concentration led to decreased environmental quality.

  13. Granger-causality maps of diffusion processes

    Science.gov (United States)

    Wahl, Benjamin; Feudel, Ulrike; Hlinka, Jaroslav; Wächter, Matthias; Peinke, Joachim; Freund, Jan A.

    2016-02-01

    Granger causality is a statistical concept devised to reconstruct and quantify predictive information flow between stochastic processes. Although the general concept can be formulated model-free it is often considered in the framework of linear stochastic processes. Here we show how local linear model descriptions can be employed to extend Granger causality into the realm of nonlinear systems. This novel treatment results in maps that resolve Granger causality in regions of state space. Through examples we provide a proof of concept and illustrate the utility of these maps. Moreover, by integration we convert the local Granger causality into a global measure that yields a consistent picture for a global Ornstein-Uhlenbeck process. Finally, we recover invariance transformations known from the theory of autoregressive processes.

  14. The Gravity Dual of Boundary Causality

    CERN Document Server

    Engelhardt, Netta

    2016-01-01

    In gauge/gravity duality, points which are not causally related on the boundary cannot be causally related through the bulk; this is the statement of boundary causality. By the Gao-Wald theorem, the averaged null energy condition in the bulk is sufficient to ensure this property. Here we proceed in the converse direction: we derive a necessary as well as sufficient condition for the preservation of boundary causality under perturbative (quantum or stringy) corrections to the bulk. The condition that we find is a (background-dependent) constraint on the amount by which light cones can "open" over all null bulk geodesics. We show that this constraint is weaker than the averaged null energy condition.

  15. Selecting appropriate cases when tracing causal mechanisms

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    2016-01-01

    , ontological determinism, causal asymmetry and causal homogeneity and the importance of context. We then develop a set of case selection guidelines that are in methodological alignment with these underlying assumptions. Section 4 develops guidelines for research where the mechanism is the primary focus......The last decade has witnessed resurgence in the interest in studying the causal mechanisms linking causes and outcomes in the social sciences. This article explores the overlooked implications for case selection when tracing mechanisms using in-depth case studies. Our argument is that existing case...... selection guidelines are appropriate for research aimed at making cross-case claims about causal relationships, where case selection is primarily used to control for other causes. However, existing guidelines are not in alignment with case-based research that aims to trace mechanisms, where the goal is to...

  16. Quantum probability assignment limited by relativistic causality.

    Science.gov (United States)

    Han, Yeong Deok; Choi, Taeseung

    2016-01-01

    Quantum theory has nonlocal correlations, which bothered Einstein, but found to satisfy relativistic causality. Correlation for a shared quantum state manifests itself, in the standard quantum framework, by joint probability distributions that can be obtained by applying state reduction and probability assignment that is called Born rule. Quantum correlations, which show nonlocality when the shared state has an entanglement, can be changed if we apply different probability assignment rule. As a result, the amount of nonlocality in quantum correlation will be changed. The issue is whether the change of the rule of quantum probability assignment breaks relativistic causality. We have shown that Born rule on quantum measurement is derived by requiring relativistic causality condition. This shows how the relativistic causality limits the upper bound of quantum nonlocality through quantum probability assignment. PMID:26971717

  17. The Temporal Logic of Causal Structures

    CERN Document Server

    Kleinberg, Samantha

    2012-01-01

    Computational analysis of time-course data with an underlying causal structure is needed in a variety of domains, including neural spike trains, stock price movements, and gene expression levels. However, it can be challenging to determine from just the numerical time course data alone what is coordinating the visible processes, to separate the underlying prima facie causes into genuine and spurious causes and to do so with a feasible computational complexity. For this purpose, we have been developing a novel algorithm based on a framework that combines notions of causality in philosophy with algorithmic approaches built on model checking and statistical techniques for multiple hypotheses testing. The causal relationships are described in terms of temporal logic formulae, reframing the inference problem in terms of model checking. The logic used, PCTL, allows description of both the time between cause and effect and the probability of this relationship being observed. We show that equipped with these causal f...

  18. Causality and the semantics of provenance

    CERN Document Server

    Cheney, James

    2010-01-01

    Provenance, or information about the sources, derivation, custody or history of data, has been studied recently in a number of contexts, including databases, scientific workflows and the Semantic Web. Many provenance mechanisms have been developed, motivated by informal notions such as influence, dependence, explanation and causality. However, there has been little study of whether these mechanisms formally satisfy appropriate policies or even how to formalize relevant motivating concepts such as causality. We contend that mathematical models of these concepts are needed to justify and compare provenance techniques. In this paper we review a theory of causality based on structural models that has been developed in artificial intelligence, and describe work in progress on a causal semantics for provenance graphs.

  19. Causality and the Semantics of Provenance

    Directory of Open Access Journals (Sweden)

    James Cheney

    2010-06-01

    Full Text Available Provenance, or information about the sources, derivation, custody or history of data, has been studied recently in a number of contexts, including databases, scientific workflows and the Semantic Web. Many provenance mechanisms have been developed, motivated by informal notions such as influence, dependence, explanation and causality. However, there has been little study of whether these mechanisms formally satisfy appropriate policies or even how to formalize relevant motivating concepts such as causality. We contend that mathematical models of these concepts are needed to justify and compare provenance techniques. In this paper we review a theory of causality based on structural models that has been developed in artificial intelligence, and describe work in progress on using causality to give a semantics to provenance graphs.

  20. Causality and the Semantics of Provenance

    CERN Document Server

    Cheney, James

    2010-01-01

    Provenance, or information about the sources, derivation, custody or history of data, has been studied recently in a number of contexts, including databases, scientific workflows and the Semantic Web. Many provenance mechanisms have been developed, motivated by informal notions such as influence, dependence, explanation and causality. However, there has been little study of whether these mechanisms formally satisfy appropriate policies or even how to formalize relevant motivating concepts such as causality. We contend that mathematical models of these concepts are needed to justify and compare provenance techniques. In this paper we review a theory of causality based on structural models that has been developed in artificial intelligence, and describe work in progress on using causality to give a semantics to provenance graphs.

  1. Ten simple rules for dynamic causal modeling.

    NARCIS (Netherlands)

    Stephan, K.E.; Penny, W.D.; Moran, R.J.; Ouden, H.E.M. den; Daunizeau, J.; Friston, K.J.

    2010-01-01

    Dynamic causal modeling (DCM) is a generic Bayesian framework for inferring hidden neuronal states from measurements of brain activity. It provides posterior estimates of neurobiologically interpretable quantities such as the effective strength of synaptic connections among neuronal populations and

  2. A Causal Model for Diagnostic Reasoning

    Institute of Scientific and Technical Information of China (English)

    PENG Guoqiang; CHENG Hu

    2000-01-01

    Up to now, there have been many methods for knowledge representation and reasoning in causal networks, but few of them include the research on the coactions of nodes. In practice, ignoring these coactions may influence the accuracy of reasoning and even give rise to incorrect reasoning. In this paper, based on multilayer causal networks, the definitions on coaction nodes are given to construct a new causal network called Coaction Causal Network, which serves to construct a model of neural network for diagnosis followed by fuzzy reasoning, and then the activation rules are given and neural computing methods are used to finish the diagnostic reasoning. These methods are proved in theory and a method of computing the number of solutions for the diagnostic reasoning is given. Finally, the experiments and the conclusions are presented.

  3. Causal Structure and Birefringence in Nonlinear Electrodynamics

    OpenAIRE

    de Melo, C. A. M.; Medeiros, L. G.; Pompeia, P. J.(Instituto de Fomento e Coordenação Industrial, Departamento de Ciência e Tecnologia Aeroespacial, Praça Mal. Eduardo Gomes 50, 12228-901, São José dos Campos, SP , Brazil)

    2014-01-01

    We investigate the causal structure of general nonlinear electrodynamics and determine which Lagrangians generate an effective metric conformal to Minkowski. We also proof that there is only one analytic nonlinear electrodynamics presenting no birefringence.

  4. The Causal Effects of Father Absence

    OpenAIRE

    McLanahan, Sara; TACH, LAURA; Schneider, Daniel

    2013-01-01

    The literature on father absence is frequently criticized for its use of cross-sectional data and methods that fail to take account of possible omitted variable bias and reverse causality. We review studies that have responded to this critique by employing a variety of innovative research designs to identify the causal effect of father absence, including studies using lagged dependent variable models, growth curve models, individual fixed effects models, sibling fixed effects models, natural ...

  5. Inter-causal Independence and Heterogeneous Factorization

    OpenAIRE

    Zhang, Nevin Lianwen; Poole, David L

    2013-01-01

    It is well known that conditional independence can be used to factorize a joint probability into a multiplication of conditional probabilities. This paper proposes a constructive definition of inter-causal independence, which can be used to further factorize a conditional probability. An inference algorithm is developed, which makes use of both conditional independence and inter-causal independence to reduce inference complexity in Bayesian networks.

  6. Catastrophizing and Causal Beliefs in Whiplash

    OpenAIRE

    Buitenhuis, J.; de Jong, P J; Jaspers, J. P. C.; Groothoff, J. W.

    2008-01-01

    Study Design. Prospective cohort study. Objective. This study investigates the role of pain catastrophizing and causal beliefs with regard to severity and persistence of neck complaints after motor vehicle accidents. Summary of Background Data. In previous research on low back pain, somatoform disorders and chronic fatigue syndrome, pain catastrophizing and causal beliefs were found to be related to perceived disability and prognosis. Furthermore, it has been argued with respect to whiplash t...

  7. Causal Inference in Urban and Regional Economics

    OpenAIRE

    Nathaniel Baum-Snow; Fernando Ferreira

    2014-01-01

    Recovery of causal relationships in data is an essential part of scholarly inquiry in the social sciences. This chapter discusses strategies that have been successfully used in urban and regional economics for recovering such causal relationships. Essential to any successful empirical inquiry is careful consideration of the sources of variation in the data that identify parameters of interest. Interpretation of such parameters should take into account the potential for their heterogeneity as ...

  8. Causal transmission in reduced-form models

    OpenAIRE

    Vassili Bazinas; Bent Nielsen

    2015-01-01

    We propose a method to explore the causal transmission of a catalyst variable through two endogenous variables of interest. The method is based on the reduced-form system formed from the conditional distribution of the two endogenous variables given the catalyst. The method combines elements from instru- mental variable analysis and Cholesky decomposition of structural vector autoregressions. We give conditions for uniqueness of the causal transmission.

  9. Invited Commentary: Causal Diagrams and Measurement Bias

    OpenAIRE

    Hernán, Miguel A.; Cole, Stephen R.

    2009-01-01

    Causal inferences about the effect of an exposure on an outcome may be biased by errors in the measurement of either the exposure or the outcome. Measurement errors of exposure and outcome can be classified into 4 types: independent nondifferential, dependent nondifferential, independent differential, and dependent differential. Here the authors describe how causal diagrams can be used to represent these 4 types of measurement bias and discuss some problems that arise when using measured expo...

  10. A Definition and Graphical Representation for Causality

    OpenAIRE

    Heckerman, David; Shachter, Ross D.

    2013-01-01

    We present a precise definition of cause and effect in terms of a fundamental notion called unresponsiveness. Our definition is based on Savage's (1954) formulation of decision theory and departs from the traditional view of causation in that our causal assertions are made relative to a set of decisions. An important consequence of this departure is that we can reason about cause locally, not requiring a causal explanation for every dependency. Such local reasoning can be beneficial because i...

  11. Causales de ausencia de responsabilidad penal

    Directory of Open Access Journals (Sweden)

    Jaime Sandoval Fernández

    2003-01-01

    Full Text Available Este trabajo se ocupa de las causales de ausencia de responsabilidad penal, especialmente de aquellas que tienen efecto en el injusto. Como subtemas se delimita el concepto de responsabilidad penal y su ausencia. Se estudian las principales teorias a cerca de la relación tipicidad-antijuridicidad y su incidencia en el derecho penal colombiano. Por último contiene una propuesta acerca de cómo deberian agruparse las causales del arto 32 C. PlOO.

  12. Novas linhagens de repôlho e couve-flor para o Estado de São Paulo Improved cabbage and cauliflower types for São Paulo

    Directory of Open Access Journals (Sweden)

    Leocádio de Souza Camargo

    1956-01-01

    Full Text Available A experimentação com repôlho (Brassica oleracea L. var. capitata L. e couve-flor (B. oleracea L. var. botrytis cauliflora, Gars, D.C. foi intensificada no Instituto Agronômico a partir de 1941 e, em 1944 iniciaram-se os trabalhos sôbre o seu melhoramento. No presente trabalho são feitas referências sobre florescimento, polinização, genética, problemas da produção de sementes, deficiência de boro, época de semeação para produção de cabeças e de sementes, pragas e moléstias. Experimentaram-se 74 variedades de repôlho e 59 de couve-flor. O maior grupo de variedades produz bem na época fresca do ano, quando as temperaturas médias mensais variam em tôrno de 22,5°C durante o crescimento, e de 16,5°C, na época de formação de cabeças. Para plantio na época quente do ano, com temperaturas médias mensais variando de 20,4 a 22,6°C, durante o crescimento, e de 18 a 22,2°C, na formação de cabeças, prestam-se a variedade de repôlho paulista "Louco" (I.A.C. n.° 758 melhorada no Instituto Agronômico, e a couve-flor "Early Benares", n.° 1383, procedente de Sutton's Seed, Índia, também adaptada às nossas condições climáticas. Em 1944 iniciou-se em Campinas, na E. E. Central, o melhoramento do repolho "Louco" com material procedente de Mogí das Cruzes, São Paulo. Seus defeitos foram eliminados, possuindo-se dêle boas linhagens. Dêsse repôlho foram produzidas, em campos de cooperação da Divisão de Fomento Agrícola, em 1950 e 1951, respectivamente 750 e 722,5 kg de sementes, obtendo-se em média, 26,5 g por planta ou 53 g por m2. Visando à produção de sementes, a melhor época de semeadura é dezembro. As cabeças formam-se em março e abril; após a retirada da cabeça as gemas do caule brotam; desses brotos, dois dos mais fortes devem ficar para a produção de sementes. O florescimento e a colheita das sementes dão-se em épocas favoráveis. As sementes são colhidas desde 160 dias após o corte da cabe

  13. Associative foundation of causal learning in rats.

    Science.gov (United States)

    Polack, Cody W; McConnell, Bridget L; Miller, Ralph R

    2013-03-01

    Are humans unique in their ability to interpret exogenous events as causes? We addressed this question by observing the behavior of rats for indications of causal learning. Within an operant motor-sensory preconditioning paradigm, associative surgical techniques revealed that rats attempted to control an outcome (i.e., a potential effect) by manipulating a potential exogenous cause (i.e., an intervention). Rats were able to generate an innocuous auditory stimulus. This stimulus was then paired with an aversive stimulus. The animals subsequently avoided potential generation of the predictive cue, but not if the aversive stimulus was subsequently devalued or the predictive cue was extinguished (Exp. 1). In Experiment 2, we demonstrated that the aversive stimulus we used was in fact aversive, that it was subject to devaluation, that the cue-aversive stimulus pairings did make the cue a conditioned stimulus, and that the cue was subject to extinction. In Experiments 3 and 4, we established that the decrease in leverpressing observed in Experiment 1 was goal-directed instrumental behavior rather than purely a product of Pavlovian conditioning. To the extent that interventions suggest causal reasoning, it appears that causal reasoning can be based on associations between contiguous exogenous events. Thus, contiguity appears capable of establishing causal relationships between exogenous events. Our results challenge the widely held view that causal learning is uniquely human, and suggest that causal learning is explicable in an associative framework. PMID:22562460

  14. Nitrogênio e boro na produção e incidência de haste oca em couve-flor 'Sharon' Nitrogen and boron on yield and incidence of hollow stem disorder in cauliflower 'Sharon'

    Directory of Open Access Journals (Sweden)

    Simone da Costa Mello

    2009-09-01

    Full Text Available Objetivou-se avaliar a influência de doses de nitrogênio (100, 150, 200 e 250 kg ha-1 e de boro (0; 1,5 kg ha-1 no plantio e 1,5 kg ha-1 aos 45 dias após o transplante das mudas ; 3,0 kg ha-1 no plantio na produtividade e na ocorrência de haste oca em couve-flor 'Sharon', sob blocos ao acaso, esquema fatorial, com quatro repetições. O experimento foi realizado em Piracicaba (SP, em condições de campo, em Nitossolo Vermelho Eutrófico, de novembro de 2005 a março de 2006. O nitrogênio e o boro não influenciaram a produtividade total e comercial, a massa da inflorescência, os teores de N e de B na folha e na inflorescência. A incidência de haste oca foi reduzida com a aplicação de B.The objective was evaluate nitrogen (100, 150, 200 and 250 kg ha-1 and boron rates (0; 1.5 kg ha-1 at planting and 1.5 kg ha-1 after 45 transplanting days and 3.0 kg ha-1 at planting on yield and hollow stem disorder of cauliflower 'Sharon' in blocks randomized in factorial design with four replications. The experiment was carried out in field conditions, in Piracicaba, São Paulo State, at Nitossolo Vermelho Eutrófico soil during November/2005 until March/2006. The nitrogen and boron did not effect on commercial and total yield, inflorescence mass, N and B levels of leaves and inflorescences. Hollow stem incidence was reduced by B application.

  15. Algas planctônicas de um lago artificial do Jardim Botânico Chico Mendes, Goiânia, Goiás: florística e algumas considerações ecológicas

    Directory of Open Access Journals (Sweden)

    NOGUEIRA I. de S.

    1999-01-01

    Full Text Available Este trabalho visa estudar a composição e fazer algumas considerações ecológicas das algas planctônicas que ocorrem em um dos lagos artificiais do Jardim Botânico Chico Mendes, Goiânia, Goiás, enfocando a florística e aspectos ecológicos entre períodos de seca, início de chuva e período chuvoso, juntamente com alguns parâmetros abióticos (pH, oxigênio - dissolvido e saturado - temperatura do ar e da água, nitratos, nitritos, alcalinidade, cloretos, turbidez, DBO e precipitação. Foram reconhecidos 77 táxons, distribuídos em 9 classes, destes 68,7% foram registrados como sendo primeira ocorrência para o estado e Chlorophyceae, a classe mais representativa. Durante o período chuvoso observou-se maior riqueza específica, com 11 táxons abundantes. No entanto, o início das chuvas apresentou maior densidade fitoplanctônica (13.590 ind/ml, com 18 espécies abundantes, dentre estas se destacaram Nephrochlamys allanthoidea (Chlorophyceae e Phacus dangeardi (Euglenophyceae que apresentaram elevadas densidades. As águas do ambiente estudado mostraram-se com características meso a oligotróficas no período seco e oligotróficas no início das chuvas, variando de levemente ácida a alcalina, com temperatura entre 24ºC e 26ºC.

  16. Preschoolers prefer to learn causal information

    Directory of Open Access Journals (Sweden)

    Aubry eAlvarez

    2015-02-01

    Full Text Available Young children, in general, appear to have a strong drive to explore the environment in ways that reveal its underlying causal structure. But are they really attuned specifically to casual information in this quest for understanding, or do they show equal interest in other types of non-obvious information about the world? To answer this question, we introduced 20 three-year-old children to two puppets who were anxious to tell the child about a set of novel artifacts and animals. One puppet consistently described causal properties of the items while the other puppet consistently described carefully matched non-causal properties of the same items. After a familiarization period in which children learned which type of information to expect from each informant, children were given the opportunity to choose which they wanted to hear describe each of eight pictured test items. On average, children chose to hear from the informant that provided causal descriptions on 72% of the trials. This preference for causal information has important implications for explaining the role of conceptual information in supporting early learning and may suggest means for maximizing interest and motivation in young children.

  17. Quantum causality in closed timelike curves

    Science.gov (United States)

    Korotaev, S. M.; Kiktenko, E. O.

    2015-08-01

    Although general relativity allows the existence of closed timelike curves (CTCs), self-consistency problems arise (the ‘grandfather paradox’ among others). It is known that quantum mechanical consideration of the matter formally removes all the paradoxes, but the questions about causal structure remain. On the other hand, the idea of postselected CTCs (P-CTC) in quantum teleportation has know been put forward and experimentally implemented. We consider these problems with the aid of quantum causal analysis, where causality is defined without invoking the time relation. It implements the Cramer principle of weak causality, which admits time reversal in entangled states. We analyze Deutsch CTCs (D-CTC) with different kinds of interactions between the chronology-violating and chronology-respecting particles, with refined inferences about mixedness, quantum/classical correlations, entanglement and thermodynamics in the D-CTC. The main result is that time reversal causality can really exist, however, the final quantum state does not place retrospective constraints on the initial state, instead the final state can influence the state inside the D-CTC. This is effectively the implementation of Novikov self-consistency principle. The P-CTC has radically different properties; in particular, if the initial state was pure, the final state is always pure too. Self-consistency is controlled by the initial state-dependent traversability of the P-CTC.

  18. Causality, initial conditions and inflationary magnetogenesis

    CERN Document Server

    Tsagas, Christos G

    2016-01-01

    The post-inflationary evolution of inflation-produced magnetic fields, conventional or not, can change dramatically when two fundamental issues are accounted for. The first is causality, which demands that local physical processes can never affect superhorizon perturbations. The second is the nature of the transition from inflation to reheating and then to the radiation era, which determine the initial conditions at the start of these epochs. Technically, the latter issue can be addressed by appealing to Israel's junction conditions. Causality implies that inflationary magnetic fields dot not freeze into the matter until they have re-entered the causal horizon. The nature of cosmological transitions and the associated initial conditions, on the other hand, determine the large-scale magnetic evolution after inflation. Put together, the two can slow down the adiabatic decay of superhorizon-sized magnetic fields throughout their post-inflationary life and thus lead to considerably stronger residual strengths. Th...

  19. Causal Mediation Analyses for Randomized Trials.

    Science.gov (United States)

    Lynch, Kevin G; Cary, Mark; Gallop, Robert; Ten Have, Thomas R

    2008-01-01

    In the context of randomized intervention trials, we describe causal methods for analyzing how post-randomization factors constitute the process through which randomized baseline interventions act on outcomes. Traditionally, such mediation analyses have been undertaken with great caution, because they assume that the mediating factor is also randomly assigned to individuals in addition to the randomized baseline intervention (i.e., sequential ignorability). Because the mediating factors are typically not randomized, such analyses are unprotected from unmeasured confounders that may lead to biased inference. We review several causal approaches that attempt to reduce such bias without assuming that the mediating factor is randomized. However, these causal approaches require certain interaction assumptions that may be assessed if there is enough treatment heterogeneity with respect to the mediator. We describe available estimation procedures in the context of several examples from the literature and provide resources for software code. PMID:19484136

  20. Bulk viscous cosmology with causal transport theory

    International Nuclear Information System (INIS)

    We consider cosmological scenarios originating from a single imperfect fluid with bulk viscosity and apply Eckart's and both the full and the truncated Müller-Israel-Stewart's theories as descriptions of the non-equilibrium processes. Our principal objective is to investigate if the dynamical properties of Dark Matter and Dark Energy can be described by a single viscous fluid and how such description changes when a causal theory (Müller-Israel-Stewart's, both in its full and truncated forms) is taken into account instead of Eckart's non-causal one. To this purpose, we find numerical solutions for the gravitational potential and compare its behaviour with the corresponding ΛCDM case. Eckart's and the full causal theory seem to be disfavoured, whereas the truncated theory leads to results similar to those of the ΛCDM model for a bulk viscous speed in the interval 10−11 || cb2 ∼−8

  1. The causal meaning of Hamilton's rule.

    Science.gov (United States)

    Okasha, Samir; Martens, Johannes

    2016-03-01

    Hamilton's original derivation of his rule for the spread of an altruistic gene (rb>c) assumed additivity of costs and benefits. Recently, it has been argued that an exact version of the rule holds under non-additive pay-offs, so long as the cost and benefit terms are suitably defined, as partial regression coefficients. However, critics have questioned both the biological significance and the causal meaning of the resulting rule. This paper examines the causal meaning of the generalized Hamilton's rule in a simple model, by computing the effect of a hypothetical experiment to assess the cost of a social action and comparing it to the partial regression definition. The two do not agree. A possible way of salvaging the causal meaning of Hamilton's rule is explored, by appeal to R. A. Fisher's 'average effect of a gene substitution'. PMID:27069669

  2. Causal inheritance in plane wave quotients

    International Nuclear Information System (INIS)

    We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general spacetime to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp-waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave spacetimes. We show that all other quotients preserve stable causality

  3. Causal inheritence in plane wave quotients

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, Veronika E.; Rangamani, Mukund; Ross, Simon F.

    2003-11-24

    We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general spacetime to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp-waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave spacetimes. We show that all other quotients preserve stable causality.

  4. Normalizing the causality between time series

    Science.gov (United States)

    Liang, X. San

    2015-08-01

    Recently, a rigorous yet concise formula was derived to evaluate information flow, and hence the causality in a quantitative sense, between time series. To assess the importance of a resulting causality, it needs to be normalized. The normalization is achieved through distinguishing a Lyapunov exponent-like, one-dimensional phase-space stretching rate and a noise-to-signal ratio from the rate of information flow in the balance of the marginal entropy evolution of the flow recipient. It is verified with autoregressive models and applied to a real financial analysis problem. An unusually strong one-way causality is identified from IBM (International Business Machines Corporation) to GE (General Electric Company) in their early era, revealing to us an old story, which has almost faded into oblivion, about "Seven Dwarfs" competing with a giant for the mainframe computer market.

  5. Análisis florístico y fitogeográfico del sector Nororinetal de la Sierra de La Macarena (Meta, Colombia)

    OpenAIRE

    Murillo Aldana José Carmelo; Carvajal Rojas Lyndon

    2006-01-01

    Se realizó el análisis florístico y fitogeográfico para el sector nororiental de la Sierra de La Macarena en un rango altitudinal de 400-800 m, en inmediaciones del municipio de San Juan de Arama (Meta, Colombia), en las veredas Monserrate Bajo, Morro Bello y Curía. Con base en fotografías aéreas se definieron tres unidades de paisajes: bosque de galería, bosque poco intervenido y sabanas sobre afloramientos rocosos. Se encontraron 558 especies distribuidas en 112 familias y 343 géneros. Las ...

  6. Composición florística de cuatro ambientes en la ciénaga de La Palmita, estado Zulia, Venezuela

    OpenAIRE

    Antonio Vera; Ángel Villareal; Maritza Martínez

    2010-01-01

    Se determinó la composición florística en cuatro ambientes de La Ciénaga de La Palmita, estado Zulia, Venezuela: ensenada, berma de arena, bosque de manglar y ecotono. Se realizaron 16 muestreos quincenales entre octubre 2007 y mayo 2008, tanto en el período seco como en el lluvioso, siguiendo una dirección agua-tierra y oeste-este. Se identificaron 32 familias, 43 géneros y 48 especies; estas últimas se agruparon en 17 árboles, siete arbustos, 14 hierbas, tres hemiparásitas y siete lianas. S...

  7. Morfología de la flor y de la semilla de papaya (carica papaya l.): variedad maradol e híbrido tainung-1

    OpenAIRE

    Gil, Arlette Ivonne; Miranda, Diego

    2010-01-01

    Con el objetivo de analizar la morfología de la flor y de la semilla de papaya (Carica papaya L.) de la variedad ‘Maradol’ y el híbrido ‘Tainung-1’, se recolectó el material vegetal en dos plantaciones y se llevaron al laboratorio de Fisiología de Cultivos, Facultad de Agronomía, Universidad Nacional de Colombia, Bogotá, con el fin de realizar las descripciones correspondientes de los tres tipos de flores (femeninas, hermafroditas y estaminadas) y de la semilla, sus características externas (...

  8. Análisis florístico en tepetates del estado de Tlaxcala Floristic analysis in tepetates of Tlaxcala State

    OpenAIRE

    José Luis Martínez-y-Pérez; Gonzalo Castillo-Campos; Ma. Guadalupe Santiago-Martínez; Laura V. Hernández-Cuevas

    2011-01-01

    En México no se conocen trabajos sobre florística de los tepetates, ya que se consideran suelos improductivos y poco interesantes para su estudio. Se recolectó material botánico durante 18 meses en 2 localidades del estado de Tlaxcala con presencia de tepetates y en 40 unidades experimentales con barreras para retención de sedimentos y 40 sin barreras, que también fueron utilizadas para introducir arbustos nativos micorrizados. Las plantas se identificaron taxonómicamente y se depositaron en ...

  9. Detectives salvajes: La Cofradía de la Flor Solar : Mitos y leyendas de la banda madre del rock platense

    OpenAIRE

    Jalil, Oscar; Magistrali, Fernando; COHEN, Ricardo; Díaz, Juan Fernando; Pinchevsky, Jorge; Gornatti, Quique

    2014-01-01

    El programa Detectives salvajes de FM Universidad - 107.5 dedica una emisión a la historia de la banda platense La Cofradía de la Flor Solar. Con testimonios de los protagonistas, se refieren al origen en 1966, contexto, integrantes, historia, ideología y obra del grupo musical considerado el primer antecedente del rock platense y nacional. Su relación con la Escuela Superior de Bellas Artes de la UNLP, su devenir en el marco de la historia nacional. Se escuchan fragmentos del programa Cultur...

  10. Estrutura do estrato herbáceo na formação aberta de Clusia do Parque Nacional da Restinga de Jurubatiba, RJ, Brasil Herb layer structure of Clusia scrub in the Restinga de Jurubatiba National Park, Rio de Janeiro, Brazil

    OpenAIRE

    Miriam Cristina Alvarez Pereira; Sandra Zorat Cordeiro; Dorothy Sue Dunn de Araujo

    2004-01-01

    No Parque Nacional da Restinga de Jurubatiba localiza-se o site 5 do Programa de Pesquisas Ecológicas de Longa Duração (PELD), região de grande diversidade de hábitats e riqueza florística nas restingas do Norte do Estado do Rio de Janeiro. Para descrever a composição florística e estrutura do estrato herbáceo da formação aberta de Clusia foram amostrados todos os indivíduos deste estrato utilizando-se o método de parcelas. Em três diferentes áreas foram distribuídos 200 quadrados de 1m², tot...

  11. Contribución para la caracterización bioclimática del Norte de Portugal. La transición florística atlántico-mediterránea.

    OpenAIRE

    Martins, Alvaro R.; Crespí, Antonio L.; Castro, Adriano; Fernandes, Claúdia P.; Rocha, Joao; de Castro, Carlos; Bernardos, Sonia; Amich García, Francisco

    2008-01-01

    Contribución para la caracterización bioclimática del norte de Portugal. La transición florística atlántico-mediterránea. Este trabajo se incluye en la serie de trabajos ya iniciados por Crespí et al. (2001), con el objetivo de contribuir al conocimiento bioclimático del Norte de Portugal, a través de la información florística presente. En este sentido, y para proceder a una posible cartografia de las áreas biogeográficas naturales desde una perspectiva termopluviométrica, son ahora introduci...

  12. Hume’s understanding of causal explanation

    Directory of Open Access Journals (Sweden)

    Stefanović Igor

    2015-01-01

    Full Text Available This article deals with actuality of Hume’s positive thesis about causality, specifically in modern science. According to Dauer, Hume in his Treatise of Human Nature does not deal with scientific theory which allows us, in modern times, to come to the truth, and then necessity. Also, he claims that observation alone, without theory is useless, which is the reason why we need science to predict future events. I intend to show that all three claims are incorrect, and to show an intimate connection of causality and our intuitions.

  13. A causally connected superluminal Warp Drive spacetime

    CERN Document Server

    Loup, F; Waite, D; Halerewicz, E F; Stabno, M; Kuntzman, M; Sims, R

    2002-01-01

    It will be shown that while horizons do not exist for warp drive spacetimes traveling at subluminal velocities horizons begin to develop when a warp drive spacetime reaches luminal velocities. However it will be shown that the control region of a warp drive ship lie within the portion of the warped region that is still causally connected to the ship even at superluminal velocities, therefore allowing a ship to slow to subluminal velocities. Further it is shown that the warped regions which are causally disconnected from a warp ship have no correlation to the ship velocity.

  14. Causal interpretation of stochastic differential equations

    DEFF Research Database (Denmark)

    Sokol, Alexander; Hansen, Niels Richard

    2014-01-01

    We give a causal interpretation of stochastic differential equations (SDEs) by defining the postintervention SDE resulting from an intervention in an SDE. We show that under Lipschitz conditions, the solution to the postintervention SDE is equal to a uniform limit in probability of postintervention...... structural equation models based on the Euler scheme of the original SDE, thus relating our definition to mainstream causal concepts. We prove that when the driving noise in the SDE is a Lévy process, the postintervention distribution is identifiable from the generator of the SDE....

  15. Causal Entropy Bound for a Spacelike Region

    Science.gov (United States)

    Brustein, R.; Veneziano, G.

    2000-06-01

    The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic spacelike region. This ``causal entropy bound,'' scaling as EV, and thus lying around the geometric mean of Bekenstein's S/ER and holographic S/A bounds, is checked in various ``critical'' situations. In the case of limited gravity, Bekenstein's bound is the strongest while naive holography is the weakest. In the case of strong gravity, our bound and Bousso's holographic bound are stronger than Bekenstein's, while naive holography is too tight, and hence typically wrong.

  16. Perfil e florística de dois trechos de mata litorânea no Município de Maricá - RJ Profile diagrams and floristic in two areas of a coastal forest in the Municipality of Maricá - RJ

    Directory of Open Access Journals (Sweden)

    Maria Cristina Lemos

    2001-12-01

    Full Text Available Na Ilha Cardosa, no sistema lagunar de Maricá-RJ, Brasil, foram realizados levantamentos florísticos, com ênfase para as lenhosas, e diagramas de perfil da vegetação de dois terrenos adjacentes: um terreno de sedimentos arenosos quaternários e outro de tabuleiro. Em cada área foi marcado um transecto de 2 x 60m, sendo amostrados todos os indivíduos lenhosos com DAS ³ 2,5 cm. Foram amostrados 276 indivíduos lenhosos e herbáceos pertencentes a 69 espécies de 33 famílias. Encontrou-se uma diferenciação florística entre as duas áreas expressa nos percentuais de espécies e famílias exclusivas a uma das áreas, e nas famílias com maior riqueza de espécies, assim como diferenças estruturais relativas à densidade, largura da copa, proporção de árvores e lianas e presença de ramificação basal do caule. As formações estudadas apresentaram, florística e fisionomicamente, semelhanças com florestas de restinga. Foram discutidas a adequação da largura e critério de inclusão utilizados para o perfil. O diagrama de perfil foi considerado um instrumento útil no estudo e comparação de estruturas fisionômicas florestais.In the Cardosa Island, located in the Maricá lagoon system, a floristic survey (especially of woody plants was carried out and profile diagrams were drawn in order to compare the vegetation of two contiguous areas: an area on quaternary sandy terrain and other on the top of a small hill (Table-land. In each area a 2 x 60m transect was delimited and every shrub, tree or liana with diameter at the base of the stem (DSB ³ 2,5cm inside of it was recorded and drawn. 276 herbaceous and woody individuals, belonging to 69 species and 33 families, were sampled. The percentage of species and families restricted to one area , and the structural features relative to density, crown width, proportion of trees and lianas and the presence of basal ramification of the stem showed differences between the two areas. Both

  17. Florística e estrutura do componete arbustivo-arbóreo de mata de restinga arenosa no Parque Estadual de Itapeva, Rio Grande do Sul Floristic and structure of the shrub-tree component of sandy restinga forest in Parque Estadual de Itapeva, Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Robson Santos

    2012-12-01

    Full Text Available Para ampliar o conhecimento sobre as matas de Restinga arenosa no Rio Grande do Sul, foi realizado estudo florístico e fitossociológico do componente arbustivo-arbóreo de um capão de Restinga do Parque Estadual de Itapeva (PEVA. Neste estudo foi usado o método de parcelas, incluindo todos os indivíduos com DAS (diâmetro a altura do solo mínimo de 2,5 cm e totalizando uma área de 0,5 ha. A composição florística resultou em riqueza total de 81 espécies. A densidade total arbustivo-arbórea no capão foi de 4.240 ind/ha. A família com maior riqueza específica foi Myrtaceae e, entre as espécies com maior valor de importância, estão Myrsine umbellata Mart. e Sorocea bonplandii (Baill. W. C. Burger. Na regeneração natural as 10 primeiras espécies acumularam 54% da regeneração natural total, com índices que variaram de 13,5% a 0,2%. A elevada riqueza observada evidenciou a contribuição da "Porta de Torres" como importante corredor migratório das espécies atlânticas na vegetação do Rio Grande do Sul, agregando novas informações sobre a florística e estrutura comunitária da Restinga do Rio Grande do Sul. Os resultados apresentados contribuirão para posteriores estudos de dinâmica no PEVA e para programas de manejo, preservação e recuperação ambiental.To enlarge the knowledge on sandy Restinga forests in Rio Grande do Sul, it was carried out a shrub-tree component phytosociological and floristic studies of a Restinga forest from Parque Estadual de Itapeva (PEVA. In this study, it was used the the plot method, including all the individuals with DAS (soil height diameter minimum of 2.5 cm and totaling an area of 0.5 ha. The floristic composition resulted in a total richness of 81 species. The shrub-tree total density in the forest was 4,240 individulas/ha. The family with the highest specific richness was Myrtaceae and, among the species with the highest importance value are Myrsine umbellata Mart. and Sorocea

  18. Florística e fitossociologia de uma floresta de vertente na Amazônia Central, Amazonas, Brasil Floristic and phytosociology of a slope forest in Central Amazonia, Amazonas, Brazil

    Directory of Open Access Journals (Sweden)

    Arlem Nascimento de Oliveira

    2004-01-01

    Full Text Available O estudo florístico e fitossociológico de árvores, palmeiras e lianas com diâmetro à altura do peito (DAP >10 cm, em uma floresta de vertente na Amazônia Central (2º35'45" S e 60º12'40" W, foi realizado empregando-se 20 parcelas de 50 x 10 m, distribuídas em dois transectos paralelos de 500 x 10 m. Foram registrados 771 indivíduos, pertencentes a 50 famílias, 120 gêneros e 239 espécies. Das espécies amostradas, 44% são "localmente raras". Sapotaceae, Lecythidaceae, Fabaceae, Caesalpiniaceae e Chrysobalanaceae constituíram as cinco famílias com maior riqueza de espécies e número de indivíduos. Dos 771 indivíduos amostrados, mais de 65% apresentaram DAP > 20 cm. As espécies Eschweilera bracteosa e Protium apiculatum apresentaram os maiores valores de IVI. Cerca de 83% das espécies encontram-se distribuídas aleatoriamente no hectare amostrado. O índice de diversidade Shannon-Wiener foi de 5,01 nats.indivíduo-1, com uniformidade de 0,91, valores altos no contexto de levantamentos semelhantes na região. A heterogeneidade edáfica e topográfica da área, as taxas de recrutamento de novos indivíduos e de espécies "localmente raras" à comunidade local, podem ter contribuído para as altas dissimilaridade (36,2% e diversidade florísticas documentadas neste estudo.The floristic and phytosociological study of trees, palms and lianas with diameter at breast height (DBH >10 cm in a forest slope in Central Amazonia (2º35'45 "S and 60º12'40" W was carried out using 20 plots of 50 x 10 m, distributed in two parallel transects of 500 x 10 m. A total of 771 plants were registered, belonging to 50 families, 120 genera and 239 species. Of the sampled species, 44% are locally rare. Families with the most species and number of individuals were Sapotaceae, Lecythidaceae, Fabaceae, Caesalpiniaceae and Chrysobalanaceae. More than 65% of the sampled plants had DBH > 20 cm. Eschweilera bracteosa and Protium apiculatum were the most

  19. Análise da florística e estrutura de floresta primária visando a seleção de espécies-chave, através de análise multivariada, para a restauração de áreas mineradas em unidades de conservação Assessment of floristic and structure of primary forest for selecting key species through multivariate analysis for conservation of mined forest areas in the protected area

    Directory of Open Access Journals (Sweden)

    Rafael Paiva Salomão

    2012-12-01

    Full Text Available Na Amazônia, vários empreendimentos minerários estão situados em unidades de conservação. A restauração ecológica após a lavra do minério abrange vários atributos. Entre esses, destaca-se a necessidade de o ecossistema restaurado conter um conjunto de espécies-chave de ocorrência no ecossistema de referência e, dessa forma, proporcionar estrutura apropriada de comunidade, além de ser constituído do maior número possível de espécies nativas. Objetivou-se, neste trabalho, analisar um índice fitossociológico e socioeconômico (IFSE, obtido por técnicas de análise multivariada. O modelo envolveu seis variáveis quantitativas (abundância, frequência, dominância, biomassa, valor comercial da madeira e quantidade de produtos florestais não madeireiros e igual número de variáveis qualitativas. Em uma área de floresta ombrófila de 1.321 ha, foram amostradas 315 parcelas de 0,25 ha, em que todos os indivíduos com DAP > 10 cm foram identificados e mensurados. Foram registrados 36.298 indivíduos, distribuídos em 898 espécies, abrangendo 62 famílias. As espécies foram ranqueadas através do índice proposto em três categorias de prioridade fitossociológica e socioeconômica (alta, média e baixa. A adequação da análise fatorial foi determinada pelos testes de Bartlett e KMO. O teste de Bartlett avaliou a significância geral da matriz de correlação a 1% de probabilidade. O teste KMO indicou que as variáveis estão correlacionadas, e o modelo fatorial apresentou nível muito bom de adequação aos dados. O uso de análise multivariada foi estatisticamente validado para o emprego do IFSE. Entre as 898 espécies analisadas, 25 foram selecionadas como prioritárias (categorias alta e média, sendo reconhecidas como espécies-chave. Foi estimada a densidade de plantio dessas espécies para recuperação de áreas mineradas na Amazônia, com condições biológicas e ambientais semelhantes às relatadas neste estudo. A

  20. A Causal Construction of Diffusion Processes

    OpenAIRE

    Banek, Tadeusz

    2010-01-01

    A simple nonlinear integral equation for Ito's map is obtained. Although, it does not include stochastic integrals, it does give causal construction of diffusion processes which can be easily implemented by iteration systems. Applications in financial modelling and extension to fBm are discussed.

  1. Causal dissipative hydrodynamics for heavy ion collisions

    CERN Document Server

    Chaudhuri, A K

    2011-01-01

    We briefly discuss the recent developments in causal dissipative hydrodynamic for relativistic heavy ion collisions. Phenomenological estimate of QGP viscosity over entropy ratio from several experimental data, e.g. STAR's $\\phi$ meson data, centrality dependence of elliptic flow, universal scaling elliptic flow etc. are discussed. QGP viscosity, extracted from hydrodynamical model analysis can have very large systematic uncertainty due to uncertain initial conditions.

  2. Causality and analyticity in quantum fields theory

    International Nuclear Information System (INIS)

    This is a presentation of results on the causal and analytical structure of Green functions and on the collision amplitudes in fields theories, for massive particles of one type, with a positive mass and a zero spin value. (A.B.)

  3. Manipulation and the causal Markov condition

    OpenAIRE

    Hausman, Daniel; Woodward, James

    2004-01-01

    This paper explores the relationship between a manipulability conception of causation and the causal Markov condition (CM). We argue that violations of CM also violate widely shared expectations—implicit in the manipulability conception—having to do with the absence of spontaneous correlations. They also violate expectations concerning the connection between independence or dependence relationships in the presence and absence of interventions.

  4. Escaping Myopia: Teaching Students about Historical Causality

    Science.gov (United States)

    Waring, Scott M.

    2010-01-01

    There are so many aspects to teaching history that are vital to creating well-rounded historical thinkers, but one of the most fundamental and most overlooked elements is the idea of causality. Far too many students do not understand the idea of causation, that there are multiple reasons for why historical events occurred and transpired in the way…

  5. Causality and Teleology in High School Biology.

    Science.gov (United States)

    Tamir, Pinchas

    1985-01-01

    Ability to distinguish between causal (cause-effect) and teleological (means-ends) explanations was measured in 1905 twelfth-grade biology students and found to be dependent on student knowledge. Although the inability to make these distinctions contributes to misconceptions in biology, appropriate instruction can easily remedy the problem. Sample…

  6. Causal and Teleological Explanations in Biology

    Science.gov (United States)

    Yip, Cheng-Wai

    2009-01-01

    A causal explanation in biology focuses on the mechanism by which a biological process is brought about, whereas a teleological explanation considers the end result, in the context of the survival of the organism, as a reason for certain biological processes or structures. There is a tendency among students to offer a teleological explanation…

  7. Comments: Causal Interpretations of Mediation Effects

    Science.gov (United States)

    Jo, Booil; Stuart, Elizabeth A.

    2012-01-01

    The authors thank Dr. Lindsay Page for providing a nice illustration of the use of the principal stratification framework to define causal effects, and a Bayesian model for effect estimation. They hope that her well-written article will help expose education researchers to these concepts and methods, and move the field of mediation analysis in…

  8. Heterogeneous Causal Effects and Sample Selection Bias

    DEFF Research Database (Denmark)

    Breen, Richard; Choi, Seongsoo; Holm, Anders

    2015-01-01

    The role of education in the process of socioeconomic attainment is a topic of long standing interest to sociologists and economists. Recently there has been growing interest not only in estimating the average causal effect of education on outcomes such as earnings, but also in estimating how cau...

  9. Inferring causality from noisy time series data

    DEFF Research Database (Denmark)

    Mønster, Dan; Fusaroli, Riccardo; Tylén, Kristian;

    2016-01-01

    even causality direction in synchronized time-series and in the presence of intermediate coupling. We find that the presence of noise deterministically reduces the level of cross-mapping fidelity, while the convergence rate exhibits higher levels of robustness. Finally, we propose that controlled noise...

  10. Linear Response Laws and Causality in Electrodynamics

    Science.gov (United States)

    Yuffa, Alex J.; Scales, John A.

    2012-01-01

    Linear response laws and causality (the effect cannot precede the cause) are of fundamental importance in physics. In the context of classical electrodynamics, students often have a difficult time grasping these concepts because the physics is obscured by the intermingling of the time and frequency domains. In this paper, we analyse the linear…

  11. As flores na pintura da "Anunciação" nos séculos XVI e XVII : a simbologia cristã e a arte decorativa

    OpenAIRE

    Silva, Alcina Silva Santos

    2012-01-01

    O objectivo da nossa investigação, que versa sobre «As flores, na pintura da Anunciação nos séculos XVI e XVII na simbologia Cristã e na Arte Decorativa», foi entender o modo como os pintores utilizaram as flores, tanto em termos simbólicos, como decorativos no período de tempo em análise. No estudo efectuado, socorremo-nos de cinco pinturas portuguesas do séc. XVI e outras cinco do séc. XVII, subordinadas ao tema da "Anunciação" a fim de compreender a razão da existência da jarra com a flor ...

  12. Contribuição de quintais agroflorestais na conservação de plantas da Caatinga, Município de Caruaru, PE, Brasil Contribution of homegardens to the conservation of caatinga plants, Municipality of Caruaru, Pernambuco State, Brazil

    OpenAIRE

    Alissandra Trajano Nunes Florentino; Elcida de Lima Araújo; Ulysses Paulino de Albuquerque

    2007-01-01

    A presente pesquisa foi realizada na zona rural do município de Caruaru, tendo como objetivo estudar a diversidade florística e a contribuição de quintais agroflorestais para a conservação da diversidade local. O trabalho foi conduzido a partir de entrevistas semi-estruturadas, associadas à técnica da turnê-guiada, realizada com os mantenedores dos quintais. Paralelamente, fez-se medição da área do quintal e de todos os indivíduos lenhosos com DNS (diâmetro ao nível do solo) > 3 cm. Registrou...

  13. Trepadeiras: florística da Estação Ecológica do Caiuá e chave de identificação vegetativa para espécies do Norte do Estado do Paraná - doi: 10.4025/actascibiolsci.v34i2.5892 Climbers: flora of the Caiuá Ecological Station and an identification key for the vegetative species of Northern Paraná State - doi: 10.4025/actascibiolsci.v34i2.5892

    Directory of Open Access Journals (Sweden)

    Juliana de Souza Carneiro

    2012-03-01

    Full Text Available As trepadeiras são plantas com alta representatividade nas florestas tropicais e de grande importância ecológica, apontadas como um dos fatores básicos que diferencia florestas tropicais de temperadas. Este trabalho apresenta as espécies de trepadeiras da Estação Ecológica do Caiuá (EECAIUÁ, município de Diamante do Norte, Estado do Paraná, inserida na floresta estacional semidecidual (FES submontana, situada à margem do rio Paranapanema. Foram encontradas 17 famílias, 44 gêneros e 53 espécies. As cinco famílias mais ricas em número de espécies perfazem juntas 57% do total encontrado. As trepadeiras herbáceas ocorrem em menor número quando comparadas às lianas, e quanto à estratégia utilizada para ascender, as volúveis são as mais diversas, seguidas pelas de órgãos preensores (gavinhas e escandentes. Uma chave de identificação para famílias, baseada em caracteres vegetativos, foi produzida para as famílias desta localidade com as famílias encontradas em outras duas no Norte do Paraná.Climbers are highly represented in tropical forests and are of great ecological importance, having been identified as one of the key factors that differentiate tropical forests from temperate rainforests. This paper presents the climber species of the Caiuá Ecological Station (EECAIUÁ in the City of Diamante do Norte, Paraná State; the Station is located in a submountainous seasonal semideciduous forest (SSF and is situated on the edge of the Paranapanema river. We found 17 families, 44 genera and 53 species of vines. The five families with the greatest number of species jointly accounted for 57% of the total species found. Herbaceous vines occurred less frequently than did lianas. When considering the climbing strategy used by the species, the graspers were the most diverse, followed by those that had tendrils (scramblers and climbers. An identification key based on vegetative characters of families found in other parts of

  14. Florística das espécies arbóreas de quatro fragmentos de Floresta Estacional Semidecídua Montana na Fazenda Dona Carolina (Itatiba/Bragança Paulista, São Paulo, Brasil. Floristic of tree species of four fragments of semi-deciduous Seasonal Montana Forest in Dona Carolina Farm (Itatiba/Bragança Paulista, São Paulo, Brazil.

    Directory of Open Access Journals (Sweden)

    Roberta Macedo CERGUEIRA Leonardo Dias MEIRELES

    2008-06-01

    Full Text Available Realizou-se um levantamento florísticoem quatro fragmentos de Floresta EstacionalSemidecídua Montana na Fazenda Dona Carolina,localizada nos municípios de Itatiba e Bragança Paulista,São Paulo, Brasil (22º 56’ 16” S e 46º 42’ 02” W.A Fazenda localiza-se dentro da unidademorfoescultural do Planalto Atlântico, com climaCfa e altitudes entre 775 e 974 m. As espéciesarbóreas de altura 2 metros foram coletadas eidentificadas. Foram amostradas 157 espécies,distribuídas em 109 gêneros e 41 famílias. As famíliasFabaceae (24 spp., Myrtaceae (15 spp., Lauraceae(9 spp. e Meliaceae (9 spp. foram as mais ricasem espécies. A similaridade florística da área emestudo com Florestas Estacionais SemidecíduasMontanas e Submontanas do Estado de São Paulofoi verificada através do índice de Jaccard e dométodo de agrupamento por média de grupos(UPGMA. Uma Twinspan foi realizada paraverificar quais espécies caracterizariam os gruposformados. A área estudada apresentou altasimilaridade florística com os fragmentos localizadosno município de Campinas, não se agrupando como fragmento florestal amostrado no mesmomunicípio. A restauração de áreas degradadas e aconservação de fragmentos localizados nessa regiãodevem, então, considerar a composição florísticados fragmentos adjacentes.A floristic survey was carried out in fourfragments of Semideciduous Seasonal MontaneForest in Dona Carolina Farm, located in themunicipalities of Itatiba and Bragança Paulista,São Paulo, Brazil (22º 56’ 16” S e 46º 42’ 02” W.The Farm is within the Atlantic Plateaumorphosculptural unit, with climate Cfa, between775 and 974 m elevation. Only tree species 2 meters high were collected and identified.A total of 157 species distributed in 109 generaand 41 families were sampled. Fabaceae (24species, Myrtaceae (15, Lauraceae (9 and Meliaceae(9 were the richest families. The floristicsimilarity between the studied area and other Semideciduous

  15. Composição e estrutura da comunidade arbórea e arbustiva em murundus no Pantanal de Poconé, Mato Grosso

    Directory of Open Access Journals (Sweden)

    Rodrigo Ferreira Morais

    2014-06-01

    Full Text Available Campos de murundus são áreas planas alagáveis, onde se encontram pequenas elevações (morrotes espalhadas na paisagem. Esses murundus apresentam solo e vegetação diferente da área circundante, uma vez que não se alagam no período chuvoso. Espera-se que o tamanho (m² e o volume (m³ dos murundus exerçam influência sobre a composição florística e a estrutura da comunidade vegetal. Assim, o objetivo deste trabalho foi analisar a composição florística e a estrutura da comunidade vegetal arbórea e arbustiva em murundus, no Pantanal de Poconé, MT, com a finalidade de responder a duas perguntas: (i Existe correlação entre a área e o volume do murundu com a riqueza e abundância da vegetação arbórea e arbustiva? (ii Existe correlação entre a área e o volume do murundu com a área basal das espécies arbóreas e arbustivas? Foram usadas parcelas para delimitar a área de campo de murundus a ser estudada. Nessas parcelas, formam mensurados a área e volume dos murundus e realizados os levantamentos florístico e fitossociológico. Foi verificado que área e volume influenciaram a riqueza, a abundância e a área basal das espécies.

  16. The causal link between energy and output growth: Evidence from Markov switching Granger causality

    International Nuclear Information System (INIS)

    In this paper we empirically investigate the causal link between energy consumption and economic growth employing a Markov switching Granger causality analysis. We carry out our investigation using annual U.S. real GDP, total final energy consumption and total primary energy consumption data which cover the period between 1968 and 2010. We find that there are significant changes in the causal relation between energy consumption and economic growth over the sample period under investigation. Our results show that total final energy consumption and total primary energy consumption have significant predictive content for real economic activity in the U.S. economy. Furthermore, the causality running from energy consumption to output growth seems to be strongly apparent particularly during the periods of economic downturn and energy crisis. We also document that output growth has predictive power in explaining total energy consumption. Furthermore, the power of output growth in predicting total energy consumption is found to diminish after the mid of 1980s. - Highlights: • Total energy consumption has predictive content for real economic activity. • The causality from energy to output growth is apparent in the periods of recession. • The causality from energy to output growth is strong in the periods of energy crisis. • Output growth has predictive power in explaining total energy consumption. • The power of output growth in explaining energy diminishes after the mid of 1980s

  17. Caracterização florística de uma área de contato entre Cerrado e Mata Atlântica na região sudoeste do Estado de São Paulo.

    Directory of Open Access Journals (Sweden)

    Nicole da Silva PINTO

    2012-06-01

    Full Text Available Remanescentes de vegetação nativa em áreas de contato florístico e fitogeográfico têm especial importância na conservação da biodiversidade. A EstaçãoExperimental de Itapeva – EExI apresenta os referidos atributos, pois, abriga remanescentes de Floresta Estacional Semidecidual e de Cerrado. A EExI está localizada na BaciaHidrográfica do Alto Paranapanema – BHAP, na região sudoeste do Estado de São Paulo, considerada altamente degradada e prioritária para estudos de flora e fauna. Os objetivos deste trabalho foram: inventariar e caracterizar a vegetação e a flora vascular da EExI; ampliar o conhecimento sobre a biodiversidade da BHAP e subsidiar propostas de manejo. Realizou-se a caracterização fisionômica e florística considerando todos os hábitos, com coletas mensais de material botânico, de maio de 2009 a dezembro de 2010. Nas duas formações presentes na EExI, Mata Atlântica (Floresta Estacional Semidecidual – FES e Cerrado (campo rupestre, campo sujo úmido, campo sujo, cerrado ralo e cerrado denso, foram registradas 605 espécies. As famílias mais ricasna FES foram: Fabaceae, Myrtaceae, Rubiaceae, Asteraceae e Lauraceae, e no Cerrado:Asteraceae, Fabaceae, Myrtaceae, Melastomataceae e Bignoniaceae. Na FES predominaramas espécies arbóreas com 54,1% do total, ao contrário do Cerrado, onde predominaram as espécies não arbóreas (67,5%. Entre as espécies levantadas, 14 estão ameaçadas de extinção, mas apenas Araucaria angustifolia é citada nas listas estadual, nacional e mundial. Considerando o mosaico de FES e fisionomias de Cerrado, a alta diversidade de espécies e a presença de espécies ameaçadas de extinção, os remanescentes de vegetação da EExI são de extrema importância para a conservação e o estudo da biodiversidade regional.Remnants of native vegetation in areas of floristic and phytogeographical contact have special importance in biodiversity conservation. The Itapeva Experimental

  18. Identification, Inference and Sensitivity Analysis for Causal Mediation Effects

    OpenAIRE

    Imai, Kosuke; Keele, Luke; Yamamoto, Teppei

    2010-01-01

    Causal mediation analysis is routinely conducted by applied researchers in a variety of disciplines. The goal of such an analysis is to investigate alternative causal mechanisms by examining the roles of intermediate variables that lie in the causal paths between the treatment and outcome variables. In this paper we first prove that under a particular version of sequential ignorability assumption, the average causal mediation effect (ACME) is nonparametrically identified. We compare our ident...

  19. Institutional Investors and Stock Market Development: A Causality Study

    OpenAIRE

    Guler Aras; Alovsat Muslumov

    2008-01-01

    This article examines causality relationships between institutional investors and stock market development based on the panel data compiled from 23 OECD countries for the years 1982 through 2000. In order to test causality relationship, Sims’ causality test based on Granger definition of causality was used in our study. Our empirical results provide evidence that there are statistically significant positive relationship between institutional investors and stock market development. The develop...

  20. Trimmed Granger causality between two groups of time series

    OpenAIRE

    Hung, Ying-Chao; Tseng, Neng-Fang; Balakrishnan, Narayanaswamy

    2014-01-01

    The identification of causal effects between two groups of time series has been an important topic in a wide range of applications such as economics, engineering, medicine, neuroscience, and biology. In this paper, a simplified causal relationship (called trimmed Granger causality) based on the context of Granger causality and vector autoregressive (VAR) model is introduced. The idea is to characterize a subset of “important variables” for both groups of time series so that the underlying cau...

  1. The Floristic and Forest Inventory of Santa Catarina State (IFFSC: methodological and operational aspects Inventário florístico florestal de Santa Catarina (IFFSC: aspectos metodológicos e operacionais

    Directory of Open Access Journals (Sweden)

    Alexander Christian Vibrans

    2010-12-01

    :SnapToGridInCell /> MicrosoftInternetExplorer4

     

    O objetivo do presente trabalho é contribuir à discussão sobre inventários florestais de abrangência regional e nacional, com enfoque em suas metodologias e em sua execução. O Inventário Florístico Florestal de Santa Catarina (IFFSC, iniciativa do governo estadual, foi concebido em 2003 para atender exigências da legislação ambiental. Após o inventário-piloto em 2005, a metodologia foi adequada em 2007 de acordo com a proposta do Inventário Florestal Nacional (IFN-BR, à época, sob discussão. O IFFSC

  2. Rubiaceae Juss. da Reserva Florestal Mata do Paraíso, Viçosa, MG, Brasil Rubiaceae Juss. from Mata do Paraíso Forest Reserve, Viçosa, Minas Gerais State, Brazil

    OpenAIRE

    Zefa Valdivina Pereira; Rita Maria de Carvalho-Okano; Flávia Cristina Pinto Garcia

    2006-01-01

    Este trabalho consiste no levantamento florístico e estudo taxonômico da família Rubiaceae, da Reserva Florestal Mata do Paraíso, Viçosa, MG. Foram registrados para a Reserva 14 gêneros compreendendo 30 espécies. Destas, 19 apresentaram hábito arbustivo e 11 são herbáceos. Os gêneros com maior número de espécies foram Psychotria (10 espécies), Borreria (quatro), Coccocypselum (três) e Coussarea e Palicourea (duas). Bathysa, Chiococca, Coutarea, Diodia, Faramea, Galium, Mitracarpus, Richardia ...

  3. A Bayesian Theory of Sequential Causal Learning and Abstract Transfer

    Science.gov (United States)

    Lu, Hongjing; Rojas, Randall R.; Beckers, Tom; Yuille, Alan L.

    2016-01-01

    Two key research issues in the field of causal learning are how people acquire causal knowledge when observing data that are presented sequentially, and the level of abstraction at which learning takes place. Does sequential causal learning solely involve the acquisition of specific cause-effect links, or do learners also acquire knowledge about…

  4. Causality and Nonlocality as Axioms for Quantum Mechanics

    OpenAIRE

    Popescu, Sandu; Rohrlich, Daniel

    1997-01-01

    Quantum mechanics permits nonlocality - both nonlocal correlations and nonlocal equations of motion - while respecting relativistic causality. Is quantum mechanics the unique theory that reconciles nonlocality and causality? We consider two models, going beyond quantum mechanics, of nonlocality: "superquantum" correlations, and nonlocal "jamming" of correlations. These models are consistent with some definitions of nonlocality and causality.

  5. Mind and Meaning: Piaget and Vygotsky on Causal Explanation.

    Science.gov (United States)

    Beilin, Harry

    1996-01-01

    Piaget's theory has been characterized as descriptive and not explanatory, not qualifying as causal explanation. Piaget was consistent in showing how his theory was both explanatory and causal. Vygotsky also endorsed causal-genetic explanation but, on the basis of knowledge of only Piaget's earliest works, he claimed that Piaget's theory was not…

  6. Sentencing goals, causal attributions, ideology, and personality.

    Science.gov (United States)

    Carroll, J S; Perkowitz, W T; Lurigio, A J; Weaver, F M

    1987-01-01

    Disparity in sentencing of criminals has been related to a variety of individual difference variables. We propose a framework establishing resonances or coherent patterns among sentencing goals, causal attributions, ideology, and personality. Two studies are described, one with law and criminology students, the other with probation officers. Relations among the different types of variables reveal two resonances among both students and officers. One comprises various conservative and moralistic elements: a tough, punitive stance toward crime; belief in individual causality for crime; high scores on authoritarianism, dogmatism, and internal locus of control; lower moral stage; and political conservatism. The second comprises various liberal elements: rehabilitation, belief in economic and other external determinants of crime, higher moral stage, and belief in the powers and responsibilities of government to correct social problems. Implications of these results are discussed for individual differences in sentencing, attribution theory, and attempts to reduce disparity. PMID:3820064

  7. An insider's guide to quantum causal histories

    International Nuclear Information System (INIS)

    A review is given of recent work aimed at constructing a quantum theory of cosmology in which all observables refer to information measurable by observers inside the universe. At the classical level the algebra of observables should be modified to take into account the fact that observers can only give truth values to observables that have to do with their backwards light cone. The resulting algebra is a Heyting rather than a Boolean algebra. The complement is non-trivial and contains information about horizons and topology change. Representation of such observables quantum mechanically requires a many-Hilbert space formalism, in which different observers make measurements in different Hilbert spaces. I describe such a formalism, called 'quantum causal histories'; examples include causally evolving spin networks and quantum computers

  8. Consistence beats causality in recommender systems

    CERN Document Server

    Zhu, Xuzhen; Hu, Zheng; Zhang, Ping; Zhou, Tao

    2015-01-01

    The explosive growth of information challenges people's capability in finding out items fitting to their own interests. Recommender systems provide an efficient solution by automatically push possibly relevant items to users according to their past preferences. Recommendation algorithms usually embody the causality from what having been collected to what should be recommended. In this article, we argue that in many cases, a user's interests are stable, and thus the previous and future preferences are highly consistent. The temporal order of collections then does not necessarily imply a causality relationship. We further propose a consistence-based algorithm that outperforms the state-of-the-art recommendation algorithms in disparate real data sets, including \\textit{Netflix}, \\textit{MovieLens}, \\textit{Amazon} and \\textit{Rate Your Music}.

  9. A New Spin on Causality Constraints

    CERN Document Server

    Hartman, Thomas; Kundu, Sandipan

    2016-01-01

    Causality in a shockwave state is related to the analytic properties of a four-point correlation function. Extending recent results for scalar probes, we show that this constrains the couplings of the stress tensor to light spinning operators in conformal field theory, and interpret these constraints in terms of the interaction with null energy. For spin-1 and spin-2 conserved currents in four dimensions, the resulting inequalities are a subset of the Hofman-Maldacena conditions for positive energy deposition. It is well known that energy conditions in holographic theories are related to causality on the gravity side; our results make a connection on the CFT side, and extend it to non-holographic theories.

  10. Normalizing the causality between time series

    CERN Document Server

    Liang, X San

    2015-01-01

    Recently, a rigorous yet concise formula has been derived to evaluate the information flow, and hence the causality in a quantitative sense, between time series. To assess the importance of a resulting causality, it needs to be normalized. The normalization is achieved through distinguishing three types of fundamental mechanisms that govern the marginal entropy change of the flow recipient. A normalized or relative flow measures its importance relative to other mechanisms. In analyzing realistic series, both absolute and relative information flows need to be taken into account, since the normalizers for a pair of reverse flows belong to two different entropy balances; it is quite normal that two identical flows may differ a lot in relative importance in their respective balances. We have reproduced these results with several autoregressive models. We have also shown applications to a climate change problem and a financial analysis problem. For the former, reconfirmed is the role of the Indian Ocean Dipole as ...

  11. Closed timelike curves and causality violation

    CERN Document Server

    Lobo, Francisco S N

    2010-01-01

    The conceptual definition and understanding of time, both quantitatively and qualitatively is of the utmost difficulty and importance. As time is incorporated into the proper structure of the fabric of spacetime, it is interesting to note that General Relativity is contaminated with non-trivial geometries which generate closed timelike curves. A closed timelike curve (CTC) allows time travel, in the sense that an observer that travels on a trajectory in spacetime along this curve, may return to an event before his departure. This fact apparently violates causality, therefore time travel and it's associated paradoxes have to be treated with great caution. The paradoxes fall into two broad groups, namely the consistency paradoxes and the causal loops. A great variety of solutions to the Einstein field equations containing CTCs exist and it seems that two particularly notorious features stand out. Solutions with a tipping over of the light cones due to a rotation about a cylindrically symmetric axis and solution...

  12. An insider's guide to quantum causal histories

    CERN Document Server

    Markopoulou, F

    2000-01-01

    A review is given of recent work aimed at constructing a quantum theory of cosmology in which all observables refer to information measurable by observers inside the universe. At the classical level the algebra of observables should be modified to take into account the fact that observers can only give truth values to observables that have to do with their backwards light cone. The resulting algebra is a Heyting rather than a Boolean algebra. The complement is non-trivial and contains information about horizons and topology change. Representation of such observables quantum mechanically requires a many-Hilbert space formalism, in which different observers make measurements in different Hilbert spaces. I describe such a formalism, called "quantum causal histories"; examples include causally evolving spin networks and quantum computers.

  13. Granger-Causality Maps of Diffusion Processes

    Czech Academy of Sciences Publication Activity Database

    Wahl, B.; Feudel, U.; Hlinka, Jaroslav; Wächter, M.; Peinke, J.; Freund, J.A.

    2016-01-01

    Roč. 93, č. 2 (2016), 022213/1-022213/9. ISSN 1539-3755 R&D Projects: GA ČR GA13-23940S; GA MZd(CZ) NV15-29835A Institutional support: RVO:67985807 Keywords : Granger causality * stochastic process * diffusion process * nonlinear dynamical systems Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.288, year: 2014

  14. Waves and causality in higher dimensions

    CERN Document Server

    Wesson, Paul S

    2015-01-01

    We give a new, wave-like solution of the field equations of five-dimensional relativity. In ordinary three-dimensional space, the waves resemble de Broglie or matter waves, whose puzzling behaviour can be better understood in terms of one or more extra dimensions. Causality is appropriately defined by a null higher-dimensional interval. It may be possible to test the properties of these waves in the laboratory.

  15. Information causality as a physical principle.

    Science.gov (United States)

    Pawłowski, Marcin; Paterek, Tomasz; Kaszlikowski, Dagomir; Scarani, Valerio; Winter, Andreas; Zukowski, Marek

    2009-10-22

    Quantum physics has remarkable distinguishing characteristics. For example, it gives only probabilistic predictions (non-determinism) and does not allow copying of unknown states (no-cloning). Quantum correlations may be stronger than any classical ones, but information cannot be transmitted faster than light (no-signalling). However, these features do not uniquely define quantum physics. A broad class of theories exist that share such traits and allow even stronger (than quantum) correlations. Here we introduce the principle of 'information causality' and show that it is respected by classical and quantum physics but violated by all no-signalling theories with stronger than (the strongest) quantum correlations. The principle relates to the amount of information that an observer (Bob) can gain about a data set belonging to another observer (Alice), the contents of which are completely unknown to him. Using all his local resources (which may be correlated with her resources) and allowing classical communication from her, the amount of information that Bob can recover is bounded by the information volume (m) of the communication. Namely, if Alice communicates m bits to Bob, the total information obtainable by Bob cannot be greater than m. For m = 0, information causality reduces to the standard no-signalling principle. However, no-signalling theories with maximally strong correlations would allow Bob access to all the data in any m-bit subset of the whole data set held by Alice. If only one bit is sent by Alice (m = 1), this is tantamount to Bob's being able to access the value of any single bit of Alice's data (but not all of them). Information causality may therefore help to distinguish physical theories from non-physical ones. We suggest that information causality-a generalization of the no-signalling condition-might be one of the foundational properties of nature. PMID:19847260

  16. Causal Mediation Analyses for Randomized Trials

    OpenAIRE

    Lynch, Kevin G.; Cary, Mark; Gallop, Robert; Ten Have, Thomas R.

    2008-01-01

    In the context of randomized intervention trials, we describe causal methods for analyzing how post-randomization factors constitute the process through which randomized baseline interventions act on outcomes. Traditionally, such mediation analyses have been undertaken with great caution, because they assume that the mediating factor is also randomly assigned to individuals in addition to the randomized baseline intervention (i.e., sequential ignorability). Because the mediating factors are t...

  17. Isocausal spacetimes may have different causal boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J L; Herrera, J [Departamento de Algebra, Geometria y Topologia, Facultad de Ciencias, Universidad de Malaga, Campus Teatinos, 29071 Malaga (Spain); Sanchez, M, E-mail: floresj@agt.cie.uma.es, E-mail: jherrera@uma.es, E-mail: sanchezm@ugr.es [Departamento de Geometria y Topologia, Facultad de Ciencias, Universidad de Granada, Avenida Fuentenueva s/n, 18071 Granada (Spain)

    2011-09-07

    We construct an example which shows that two isocausal spacetimes, in the sense introduced recently in GarcIa-Parrado and Senovilla (2003 Class. Quantum Grav. 20 625-64), may have c-boundaries which are not equal (more precisely, not equivalent, as no bijection between the completions can preserve all the binary relations induced by causality). This example also suggests that isocausality can be useful for the understanding and computation of the c-boundary.

  18. Representation and reasoning: a causal model approach

    OpenAIRE

    Nikolic, M.

    2014-01-01

    How do we represent our world and how do we use these representations to reason about it? The three studies reported in this thesis explored different aspects of the answer to this question. Even though these investigations offered diverse angles, they all originated from the same psychological theory of representation and reasoning. This is the idea that people represent the world and reason about it by constructing dynamic qualitative causal networks. The first study investigated how mock j...

  19. Reconstructing Causal Biological Networks through Active Learning

    OpenAIRE

    Cho, Hyunghoon; Berger, Bonnie; Peng, Jian

    2016-01-01

    Reverse-engineering of biological networks is a central problem in systems biology. The use of intervention data, such as gene knockouts or knockdowns, is typically used for teasing apart causal relationships among genes. Under time or resource constraints, one needs to carefully choose which intervention experiments to carry out. Previous approaches for selecting most informative interventions have largely been focused on discrete Bayesian networks. However, continuous Bayesian networks are ...

  20. A causally connected superluminal Warp Drive spacetime

    OpenAIRE

    Loup, F.; Held, R.; Waite, D; Halerewicz, Jr., E.; Stabno, M.; Kuntzman, M.; Sims, R.

    2002-01-01

    It will be shown that while horizons do not exist for warp drive spacetimes traveling at subluminal velocities horizons begin to develop when a warp drive spacetime reaches luminal velocities. However it will be shown that the control region of a warp drive ship lie within the portion of the warped region that is still causally connected to the ship even at superluminal velocities, therefore allowing a ship to slow to subluminal velocities. Further it is shown that the warped regions which ar...

  1. Extending Temporal Causal Graph For Diagnosis Problems

    OpenAIRE

    Belouaer, Lamia; Bouzid, Maroua; Mouhoub, Malek

    2009-01-01

    Poster International audience Abductive diagnosis (Brusoni et al. 1998) consists in finding explanations for given observations by using rules of inference based on the causal dependences of the system. Time is important for abductive diagnosis (Hamscher and Davis 1984), (Hamscher, Console, and Kleer 1992). There are few works in litterature handling temporal diagnosis (Kautz 1999). They differ in the expressiveness of the temporal knowledge. We propose a new approach for Temporal Diagn...

  2. Imposing causality on a matrix model

    International Nuclear Information System (INIS)

    We introduce a new matrix model that describes Causal Dynamical Triangulations (CDT) in two dimensions. In order to do so, we introduce a new, simpler definition of 2D CDT and show it to be equivalent to the old one. The model makes use of ideas from dually weighted matrix models, combined with multi-matrix models, and can be studied by the method of character expansion.

  3. Relativistic causality and position space renormalization

    CERN Document Server

    Todorov, Ivan

    2016-01-01

    We survey the causal position space renormalization with a special attention to the role of Raymond Stora in the development of the subject. Renormalization is effected by subtracting pole terms in analytically regularized amplitudes. Residues are identified with periods whose relation to recent development in number theory is emphasized. We demonstrate the possibility of integration over internal vertices in the case of a (massless) conformal theory and display the dilation and the conformal anomaly.

  4. Extracting causal relationships from Chinese written text

    OpenAIRE

    Liu, X; Hoede, C.

    2002-01-01

    Expert systems form one of the most important research areas in Artificial Intelligence. The main parts in expert systems are knowledge bases and inference engines. In the knowledge bases the main knowledge is knowledge in the form of ``IF-THEN" statements. In knowledge graphs, a new form of knowledge representation, the ``IF-THEN" statements are tied up with causal operators (CAU-relations). In this paper, we picked out some Chinese operators with ``CAU" meaning, and investigated these opera...

  5. Causality and the semantics of provenance

    OpenAIRE

    James Cheney

    2010-01-01

    Provenance, or information about the sources, derivation, custody or history of data, has been studied recently in a number of contexts, including databases, scientific workflows and the Semantic Web. Many provenance mechanisms have been developed, motivated by informal notions such as influence, dependence, explanation and causality. However, there has been little study of whether these mechanisms formally satisfy appropriate policies or even how to formalize relevant motivating concepts suc...

  6. Ten simple rules for dynamic causal modeling

    OpenAIRE

    Stephan, K E; Penny, W.D.; Moran, R. J.; den Ouden, H.E.M.; Daunizeau, J.; Friston, K J

    2010-01-01

    Dynamic causal modeling (DCM) is a generic Bayesian framework for inferring hidden neuronal states from measurements of brain activity. It provides posterior estimates of neurobiologically interpretable quantities such as the effective strength of synaptic connections among neuronal populations and their context-dependent modulation. DCM is increasingly used in the analysis of a wide range of neuroimaging and electrophysiological data. Given the relative complexity of DCM, compared to convent...

  7. Causality detection and turbulence in fusion plasmas

    OpenAIRE

    Van Milligen, B Ph; Birkenmeier, G.; Ramisch, M.; Estrada, T.; Hidalgo, C.; A. Alonso

    2013-01-01

    This work explores the potential of an information-theoretical causality detection method for unraveling the relation between fluctuating variables in complex nonlinear systems. The method is tested on some simple though nonlinear models, and guidelines for the choice of analysis parameters are established. Then, measurements from magnetically confined fusion plasmas are analyzed. The selected data bear relevance to the all-important spontaneous confinement transitions often observed in fusio...

  8. Causal beliefs about depression in different cultural groups – What do cognitive psychological theories of causal learning and reasoning predict?

    OpenAIRE

    York eHagmayer; Neele eEngelmann

    2014-01-01

    Cognitive psychological research focusses on causal learning and reasoning while cognitive anthropological and social science research tend to focus on systems of beliefs. Our aim was to explore how these two types of research can inform each other. Cognitive psychological theories (causal model theory and causal Bayes nets) were used to derive predictions for systems of causal beliefs. These predictions were then applied to lay theories of depression as a specific test case. A systematic...

  9. Causal beliefs about depression in different cultural groups—what do cognitive psychological theories of causal learning and reasoning predict?

    OpenAIRE

    Hagmayer, York; Engelmann, Neele

    2014-01-01

    Cognitive psychological research focuses on causal learning and reasoning while cognitive anthropological and social science research tend to focus on systems of beliefs. Our aim was to explore how these two types of research can inform each other. Cognitive psychological theories (causal model theory and causal Bayes nets) were used to derive predictions for systems of causal beliefs. These predictions were then applied to lay theories of depression as a specific test case. A systematic lite...

  10. Causality, initial conditions, and inflationary magnetogenesis

    Science.gov (United States)

    Tsagas, Christos G.

    2016-05-01

    The post-inflationary evolution of inflation-produced magnetic fields, conventional or not, can change dramatically when two fundamental issues are accounted for. The first is causality, which demands that local physical processes can never affect superhorizon perturbations. The second is the nature of the transition from inflation to reheating and then to the radiation era, which determine the initial conditions at the start of these epochs. Causality implies that inflationary magnetic fields do not freeze into the matter until they have re-entered the causal horizon. The nature of the cosmological transitions and the associated initial conditions, on the other hand, determine the large-scale magnetic evolution after inflation. Put together, the two can slow down the adiabatic magnetic decay on superhorizon scales throughout the Universe's post-inflationary evolution and thus lead to considerably stronger residual magnetic fields. This is "good news" for both the conventional and the nonconventional scenarios of cosmic magnetogenesis. Mechanisms operating outside standard electromagnetism, in particular, do not need to enhance their fields too much during inflation in order to produce seeds that can feed the galactic dynamo today. In fact, even conventionally produced inflationary magnetic fields might be able to sustain the dynamo.

  11. A causal dispositional account of fitness.

    Science.gov (United States)

    Triviño, Vanessa; Nuño de la Rosa, Laura

    2016-09-01

    The notion of fitness is usually equated to reproductive success. However, this actualist approach presents some difficulties, mainly the explanatory circularity problem, which have lead philosophers of biology to offer alternative definitions in which fitness and reproductive success are distinguished. In this paper, we argue  that none of these alternatives is satisfactory and, inspired by Mumford and Anjum's dispositional theory of causation, we offer a definition of fitness as a causal dispositional property. We argue that, under this framework, the distinctiveness that biologists usually attribute to fitness-namely, the fact that fitness is something different from both the physical traits of an organism and the number of offspring it leaves-can be explained, and the main problems associated with the concept of fitness can be solved. Firstly, we introduce Mumford and Anjum's dispositional theory of causation and present our definition of fitness as a causal disposition. We explain in detail each of the elements involved in our definition, namely: the relationship between fitness and the functional dispositions that compose it, the emergent character of fitness, and the context-sensitivity of fitness. Finally, we explain how fitness and realized fitness, as well as expected and realized fitness are distinguished in our approach to fitness as a causal disposition. PMID:27338570

  12. Bayesian Discovery of Linear Acyclic Causal Models

    CERN Document Server

    Hoyer, Patrik O

    2012-01-01

    Methods for automated discovery of causal relationships from non-interventional data have received much attention recently. A widely used and well understood model family is given by linear acyclic causal models (recursive structural equation models). For Gaussian data both constraint-based methods (Spirtes et al., 1993; Pearl, 2000) (which output a single equivalence class) and Bayesian score-based methods (Geiger and Heckerman, 1994) (which assign relative scores to the equivalence classes) are available. On the contrary, all current methods able to utilize non-Gaussianity in the data (Shimizu et al., 2006; Hoyer et al., 2008) always return only a single graph or a single equivalence class, and so are fundamentally unable to express the degree of certainty attached to that output. In this paper we develop a Bayesian score-based approach able to take advantage of non-Gaussianity when estimating linear acyclic causal models, and we empirically demonstrate that, at least on very modest size networks, its accur...

  13. Reliability of the Granger causality inference

    International Nuclear Information System (INIS)

    How to characterize information flows in physical, biological, and social systems remains a major theoretical challenge. Granger causality (GC) analysis has been widely used to investigate information flow through causal interactions. We address one of the central questions in GC analysis, that is, the reliability of the GC evaluation and its implications for the causal structures extracted by this analysis. Our work reveals that the manner in which a continuous dynamical process is projected or coarse-grained to a discrete process has a profound impact on the reliability of the GC inference, and different sampling may potentially yield completely opposite inferences. This inference hazard is present for both linear and nonlinear processes. We emphasize that there is a hazard of reaching incorrect conclusions about network topologies, even including statistical (such as small-world or scale-free) properties of the networks, when GC analysis is blindly applied to infer the network topology. We demonstrate this using a small-world network for which a drastic loss of small-world attributes occurs in the reconstructed network using the standard GC approach. We further show how to resolve the paradox that the GC analysis seemingly becomes less reliable when more information is incorporated using finer and finer sampling. Finally, we present strategies to overcome these inference artifacts in order to obtain a reliable GC result

  14. Cohomology Methods in Causal Perturbation Theory

    International Nuclear Information System (INIS)

    Various problems in perturbation theory of (quantum) gauge models can be rephrased in the language of cohomology theory. This was already noticed in the functional formulation of perturbative gauge theories. Causal perturbation theory is a fully quantum approach: is works only with the chronological products which are defined as operator-valued distributions in the Fock space of the model. The use of causal perturbation theory leads to similar cohomology problems; the main difference with respect to the functional methods comes from the fact that the gauge transformation of the causal approach is, essentially, the linear part of the non-linear BRST transformation.Using these methods it is possible to give a nice determination of the interaction Lagrangians for gauge models (Yang-Mills and gravitation in the linear approximation); one obtains with this method the unicity of the interaction Lagrangian up to trivial terms. The case of quantum gravity is highly non-trivial and can be generalized with this method to the massive graviton case. Going to higher orders of perturbation theory one finds quantum anomalies. Again the cohomological methods can be used to determine the generic form of these anomalies. Finally, one can investigate the arbitrariness of the chronological products in higher orders and reduce this problem to cohomology methods also.

  15. Multivariate Granger Causality Analysis of Acupuncture Effects in Mild Cognitive Impairment Patients: An fMRI Study

    Directory of Open Access Journals (Sweden)

    Shangjie Chen

    2013-01-01

    Full Text Available Evidence from clinical reports has indicated that acupuncture has a promising effect on mild cognitive impairment (MCI. However, it is still unknown that by what way acupuncture can modulate brain networks involving the MCI. In the current study, multivariate Granger causality analysis (mGCA was adopted to compare the interregional effective connectivity of brain networks by varying needling depths (deep acupuncture, DA; superficial acupuncture, SA and at different cognitive states, which were the MCI and healthy control (HC. Results from DA at KI3 in MCI showed that the dorsolateral prefrontal cortex and hippocampus emerged as central hubs and had significant causal influences with each other, but significant in HC for DA. Moreover, only several brain regions had remarkable causal interactions following SA in MCI and even few brain regions following SA in HC. Our results indicated that acupuncture at KI3 at different cognitive states and with varying needling depths may induce distinct reorganizations of effective connectivities of brain networks, and DA at KI3 in MCI can induce the strongest and more extensive effective connectivities related to the therapeutic effect of acupuncture in MCI. The study demonstrated the relatively functional specificity of acupuncture at KI3 in MCI, and needling depths play an important role in acupuncture treatments.

  16. Composición florística de pequeñas aéreas de mallines con distintas exposición y pendiente

    Directory of Open Access Journals (Sweden)

    Daniel Grima

    2015-04-01

    Full Text Available El trabajo muestra la composición florística de tres pequeñas áreas de mallines localizados en la meseta volcánica “Bella Vista” (51° 53´ S y 70° 32´ O. La misma posee una extensión aproximada de 45 km2 y presenta laderas con pendientes medias a fuertes que oscilan entre 5% y 9% (IGM 1997 y distinta exposición a la insolación y al viento. El objetivo del trabajo es caracterizar la diversidad de especies y y el estado de degradación según la aptitud forrajera (Suarez et al 2010 de los mallines en relación con la exposición y la pendiente. En gabinete se reconocieron los límites de los mallines y seleccionaron los sitios a muestrear en una imagen satelital de alta resolución espacial (IKONOS 2002. En campo se realizaron transectas perpendiculares a la pendiente y se identificaron las especies indicadoras de deterioro y de aptitud forrajera. Se estimó visualmente la cobertura vegetal y la distribución espacial de los factores de degradación.Los tres mallines exhiben composiciones florísticas y estados de degradación distintos. Carlota y Bella Vista presentan cobertura vegetal del 90 % y más diversidad florística por situarse en orientaciones menos expuestas al viento. La insolación directa favorece a Carlota en la mayor cantidad de especies relevadas (20 y 11 respectivamente, el estado de deterioro puede clasificarse de moderado a moderado severo. El mallin Gallegos Chico, con exposición oeste, recibe la acción directa del viento y su efecto abrasivo sobre las plantas afectando su porte y porcentaje de cobertura vegetal.

  17. O nexo causal em saúde/doença mental no trabalho: uma demanda para a psicologia The causal nexus on mental health/illness related to work: a new demand for psychology

    Directory of Open Access Journals (Sweden)

    Maria da Graça Jacques

    2007-01-01

    Full Text Available Estabelecer o nexo causal em saúde/doença mental no trabalho tem se apresentado como uma nova demanda à psicologia como ciência e profissão nos seus diferentes campos de atuação. Este texto examina a interlocução entre trabalho e saúde/doença mental no percurso histórico da psicologia. Apresenta, também, alguns procedimentos referentes ao diagnóstico e à justificativa de nexo causal entre trabalho e quadros psicopatológicos com base na Portaria do 1339/99 do Ministério da Saúde do Brasil. Mesmo admitindo o reducionismo que a relação causal produz em se tratando de quadros psicopatológicos, a exigência legal a impõe para o reconhecimento como doenças relacionadas com o trabalho e o acesso aos benefícios previdenciários decorrentes.Establishing the causal nexus on mental health/illness related to work is a new demand for psychology as a science and as a profession in all fields of activity. This text examines the interlocution between work and mental health/illness in the course of the history of psychology. It also presents some procedures referring to the diagnosis and the justification of the causal nexus between work and psychopathological illness. Even if we consider the causal nexus as a reductionism in psychopathological illness, this is a legal requirement to be recognized as an illness related to work and to obtain social welfare agency benefits.

  18. Identifying causal variants at loci with multiple signals of association.

    Science.gov (United States)

    Hormozdiari, Farhad; Kostem, Emrah; Kang, Eun Yong; Pasaniuc, Bogdan; Eskin, Eleazar

    2014-10-01

    Although genome-wide association studies have successfully identified thousands of risk loci for complex traits, only a handful of the biologically causal variants, responsible for association at these loci, have been successfully identified. Current statistical methods for identifying causal variants at risk loci either use the strength of the association signal in an iterative conditioning framework or estimate probabilities for variants to be causal. A main drawback of existing methods is that they rely on the simplifying assumption of a single causal variant at each risk locus, which is typically invalid at many risk loci. In this work, we propose a new statistical framework that allows for the possibility of an arbitrary number of causal variants when estimating the posterior probability of a variant being causal. A direct benefit of our approach is that we predict a set of variants for each locus that under reasonable assumptions will contain all of the true causal variants with a high confidence level (e.g., 95%) even when the locus contains multiple causal variants. We use simulations to show that our approach provides 20-50% improvement in our ability to identify the causal variants compared to the existing methods at loci harboring multiple causal variants. We validate our approach using empirical data from an expression QTL study of CHI3L2 to identify new causal variants that affect gene expression at this locus. CAVIAR is publicly available online at http://genetics.cs.ucla.edu/caviar/. PMID:25104515

  19. Estrutura da vegetação herbácea em paisagens ciliares no sul de Santa Catarina, Brasil

    OpenAIRE

    Aline Votri Guislon; Karoline Ceron; Guilherme Alves Elias; Robson Santos; Vanilde Citadini-Zanette

    2016-01-01

    As características estruturais e ecológicas da vegetação herbácea fazem com que ela seja sensível às alterações do ambiente, atuando como indicador da qualidade ambiental. No entanto, o estudo dessa comunidade ainda é incipiente em regiões neotropicais. Este estudo descreve a florística e os aspectos fitossociológicos da vegetação herbácea terrícola na mata ciliar de sete rios, no município de Urussanga, sul do estado de Santa Catarina, além de analisar e quantificar o status do conhecimento ...

  20. Floristic composition and diversity of Amazonian rainforest bryophytes in the state of Acre, Brazil Composição florística e diversidade de briófitas em floresta no estado do Acre, Brasil

    Directory of Open Access Journals (Sweden)

    Denise Pinheiro da Costa

    2003-01-01

    Full Text Available Bryophyte diversity in Amazonian Brazil is high, presently recorded at 514 species distributed among 36 families and 89 genera. Comparisions of species richness among the Amazonian states of Brazil suggests that the bryoflora of Acre is still underestimated, presently recorded at 106 species distributed among 33 families and 63 genera. After two field trips, the diversity increased 50% showing that the bryoflora is still poorly known. Collection data and comments on morphology, ecology and distribution are given for sixty-two species of bryophytes collected in the state of Acre, Brazil, which are new (fifty-two species or interesting floristic records (ten species. Microlejeunea crenulifolia (Gottsche Steph. and Stictolejeunea balfourdii Mitt. are new records for Brazil and fifty species are new records for Acre.A diversidade de briófitas na região Amazônica brasileira é alta, sendo citado atualmente, 514 espécies, em 36 famílias e 89 gêneros. Comparações entre a riqueza de espécies dos estados da Amazônia brasileira sugerem que a brioflora do Acre ainda é subestimada, contando atualmente com 106 espécies, distribuídas em 33 famílias e 63 gêneros. Após duas excursões científicas, a diversidade para o estado aumentou em 50 %, demonstrando que a brioflora ainda é pouco conhecida. Dados sobre a morfologia, ecologia e distribuição geográfica são apresentados para sessenta e duas espécies de briófitas coletadas no estado do Acre, Brasil, as quais são registros florísticos novos (cinquenta e duas espécies ou interessantes (dez espécies. Microlejeunea crenulifolia (Gottsche Steph. e Stictolejeunea balfourdii Mitt. são citadas pela primeira vez para o Brasil e cinquenta espécies são novas ocorrências para o estado do Acre.

  1. Número de anteras por flor, grãos de pólen por antera e capacidade germinativa do pólen de diferentes cultivares de macieiras Number of anthers per flower, pollen grains per anther and pollen germination capacity of different cultivars of apple trees

    Directory of Open Access Journals (Sweden)

    Celso Lopes de Albuquerque Junior

    2010-12-01

    Full Text Available O objetivo deste trabalho foi avaliar o número de anteras por flor, grãos de pólen por antera e capacidade germinativa do pólen de diferentes cultivares de macieiras. O trabalho foi executado no Laboratório de Fisiologia do Desenvolvimento e Genética Vegetal da Universidade Federal de Santa Catarina, e as coletas a campo foram realizadas na Epagri/Estação Experimental de Caçador-SC, em outubro de 2005. Foram utilizadas as seguintes cultivares comerciais de macieira desenvolvidas no Brasil: Primícia, Princesa, Fred Hough, Catarina, Baronesa, Lisgala, Suprema, Condessa, Daiane, Duquesa, Imperatriz e Joaquina. As cultivares de macieira Condessa, Princesa, Eva, Duquesa, Imperatriz, Gala, Fred Hough, Daiane, Baronesa e Suprema produzem pólen em quantidade suficiente e com boa capacidade germinativa. A cv. Condessa, embora apresente alta capacidade germinativa de pólen, produz menos anteras e grãos de pólen por antera que as demais. A cv. Princesa é a que apresenta o melhor perfil como polinizadora, por conjugar número de anteras/flor, número de grãos de pólen/antera e capacidade germinativa do pólen mais satisfatórios.The objective of this study was to evaluate the number of anthers per flower, the number of pollen grains per anther and the pollen germination capacity of different cultivars of apple trees. The study was performed at the Physiology and Plant Genetics Laboratory of Federal University of Santa Catarina. The field collecting were performed at Epagri / Caçador Experimental Station, in Santa Catarina State during October, 2005. It was used the following apple cultivars developed in Brazil: Primícia, Princesa, Fred Hough, Catarina, Baronesa, Lisgala, Suprema, Condessa, Daiane, Duquesa, Imperatriz and Joaquina. It was concluded that the apple cultivars Condessa, Princesa, Eva, Duquesa, Imperatriz, Gala, Fred Hough, Daiane, Baronesa and Suprema produce pollen grains of satisfactory quantity and of good germination

  2. Emakeel : [luuletused] / Flor Vassiljev

    Index Scriptorium Estoniae

    Vassiljev, Flor

    2004-01-01

    Sisu: Emakeel ; "Sul öeldi palumata mõneltpoolt ..." ; "Mulle ei meeldi puud, mis on pöetud ..." ; "Olen paganate usku ma ..." ; "Kui su ees on naine se ..." ; "Maa vatab ilma allikselge pilguga ..." ; "Üks väike küla ootamas meid ...". Eluloolisi andmeid autori kohta lk. 385. Luuletused paralleelselt udmurdi ja eesti keeles

  3. La organización de eventos como estrategia identitaria y evocadora de imagen turística. Estudio de caso: Girona Temps de Flors

    Directory of Open Access Journals (Sweden)

    Jiménez Morales, Mònika

    2009-01-01

    Full Text Available For the last 53 years the city of Girona organizes a massive event based on the floral art which, in its last occasions, has mobilized more than half million of visitors, many of them from all parts of Europe. Besides the flowers, the photography exhibitions or the audio-visual montages which, during the second week of May, fill the streets of the ancient part of the city, the fact is that Girona Temps de Flors represents an important communicative strategy for the territory promotion. In effect, the event, by itself, develops varied functions in the emotional area of the lived space, but there’s more. It can also become a catalyst of images, the creator of images capable of establishing a brand name of a city. The present article will show the possibilities that flow from the organisation of an event relative to the positioning of the identity and promotion of a territory.

  4. Estudio Florístico y Quimiotaxonómico de los Líquenes Silicícolas del Maresme

    OpenAIRE

    Barbero Castro, María de las Mercedes

    1998-01-01

    [spa] Al plantearnos la realización de nuestra tesis doctoral, existían dos necesidades principales a cubrir. La primera, derivada de la escasez de datos florísticos sobre los líquenes que se desarrollan sobre substratos silícicos de tierras bajas y de ambientes húmedos, próximas al litoral. La segunda necesidad a cubrir, era iniciar la línea de investigación quimiotaxonómica en los líquenes; se trataba pues de poner en marcha los métodos de análisis químicos que, en el campo de la liquenolog...

  5. La descentralización a la luz del caso Bella Flor en Ciudad Bolívar, Bogotá

    Directory of Open Access Journals (Sweden)

    Pening G Jean Philippe

    2005-12-01

    Full Text Available En Colombia, las políticas de descentralización se profundizaron con la Constitución Política de 1991 y los desarrollos legislativos posteriores. A los municipios se les devolvió la responsabilidad en inversiones en sectores como educación, salud y agua potable y saneamiento básico. Bogotá presenta los mejores indicadores colombianos, sin embargo en la ciudad conviven hogares que presentan indicadores bastante alejados del promedio de la localidad, de la ciudad y del país. Para demostrarlo, se realizó un censo en el barrio Bella Flor de la localidad de Ciudad Bolívar en Bogotá, el cual arroja unos resultados que comparamos con un censo realizado en 2000 y con resultados de encuestas del DANE.

  6. Florística, fitossociologia e fenologia de três fitofisionomias campestres no Parque Estadual de Vila Velha, Ponta Grossa, Paraná

    OpenAIRE

    Silva, Adriane Ribeiro da

    2014-01-01

    Resumo: Neste estudo, foram avaliadas a composição, estrutura, variação florística sazonal e o padrão fenológico de espécies de três fitofisionomias campestres, nos limites do Parque Estadual de Vila Velha, uma unidade de Conservação de 3.803 ha localizada no município de Ponta Grossa, na região dos Campos Gerais, Estado do Paraná. Os levantamentos foram realizados sob diferentes condições pedológicas, compreendendo áreas de estepe não-hidromórfica (ENH), estepe hidromórfica (EH) e estepe rup...

  7. Canales de distribución y estrategias de comercialización para la flor colombiana en los Estados Unidos: un marco conceptual

    Directory of Open Access Journals (Sweden)

    LUIS FELIPE SALOM SERNA

    2012-01-01

    Full Text Available El floricultor colombiano no puede desconocer los cambios en tendencias de consumo ni la consolidación del canal retail en su mercado principal, USA. El cuál generará un alto impacto en las características del negocio y el papel de los jugadores en la cadena de suministros. El objetivo de este estudio exploratorio utilizando casos múltiples, es presentar un marco de oportunidades para fortalecer la comercialización de la flor y estructurar canales de distribución acordes a las necesidades del consumidor norteamericano y a los cambios en los hábitos de compra. Las conclusiones, proponen las acciones a emprender por las empresas floricultoras estudiadas a fin de incrementar su competitividad y resolver su dilema actual: contraer oferta para mejorar el precio de venta o incrementar demanda.

  8. Composición florística de pequeñas aéreas de mallines con distintas exposición y pendiente

    OpenAIRE

    Daniel Grima; Mirian Vazquez; Paula Diez

    2015-01-01

    El trabajo muestra la composición florística de tres pequeñas áreas de mallines localizados en la meseta volcánica “Bella Vista” (51° 53´ S y 70° 32´ O). La misma posee una extensión aproximada de 45 km2 y presenta laderas con pendientes medias a fuertes que oscilan entre 5% y 9% (IGM 1997) y distinta exposición a la insolación y al viento. El objetivo del trabajo es caracterizar la diversidad de especies y y el estado de degradación según la aptitud forrajera (Suarez et al 2010) de los malli...

  9. Temporal Information of Directed Causal Connectivity in Multi-Trial ERP Data using Partial Granger Causality.

    Science.gov (United States)

    Youssofzadeh, Vahab; Prasad, Girijesh; Naeem, Muhammad; Wong-Lin, KongFatt

    2016-01-01

    Partial Granger causality (PGC) has been applied to analyse causal functional neural connectivity after effectively mitigating confounding influences caused by endogenous latent variables and exogenous environmental inputs. However, it is not known how this connectivity obtained from PGC evolves over time. Furthermore, PGC has yet to be tested on realistic nonlinear neural circuit models and multi-trial event-related potentials (ERPs) data. In this work, we first applied a time-domain PGC technique to evaluate simulated neural circuit models, and demonstrated that the PGC measure is more accurate and robust in detecting connectivity patterns as compared to conditional Granger causality and partial directed coherence, especially when the circuit is intrinsically nonlinear. Moreover, the connectivity in PGC settles faster into a stable and correct configuration over time. After method verification, we applied PGC to reveal the causal connections of ERP trials of a mismatch negativity auditory oddball paradigm. The PGC analysis revealed a significant bilateral but asymmetrical localised activity in the temporal lobe close to the auditory cortex, and causal influences in the frontal, parietal and cingulate cortical areas, consistent with previous studies. Interestingly, the time to reach a stable connectivity configuration (~250–300 ms) coincides with the deviation of ensemble ERPs of oddball from standard tones. Finally, using a sliding time window, we showed higher resolution dynamics of causal connectivity within an ERP trial. In summary, time-domain PGC is promising in deciphering directed functional connectivity in nonlinear and ERP trials accurately, and at a sufficiently early stage. This data-driven approach can reduce computational time, and determine the key architecture for neural circuit modeling. PMID:26470866

  10. Causal Depth: Aspects of a Scientific Realist Approach to Causal Explanation contra Humean Empiricism

    OpenAIRE

    Khan, Haider

    2008-01-01

    The purpose of this note is to clarify how the idea of "causal depth" can play a role in finding the more "approximately true" explanation through causal comparisons. It is not an exhaustive treatment but rather focuses on a few aspects that may be the most critical in evaluating the explanatory strengths of a theory in the social sciences. It presents a general argument which is anti-Humean on the critical side and scientific realist on the positive side. It also elucidates how explanations ...

  11. The Causality between Human Capital and Economic Growth in Oil Exporting Countries: Panel Cointegration and Causality

    OpenAIRE

    Mehrara, Mohsen

    2013-01-01

    This paper investigates the causal relationship between education and GDP in a panel of 11 selected oil exporting countries by using panel unit root tests and panel cointegration analysis for the period 1970-2010. A three-variable model is formulated with oil exports as the third variable. The results show a strong causality from oil revenues and economic growth to education in the oil exporting countries. Yet, education does not have any significant effects on GDP in short- and long-run. It ...

  12. Levantamento florístico no cerrado de Pedregulho, SP, Brasil Floristic inventory of cerrado at Pedregulho, São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Denise Sasaki

    2008-03-01

    Full Text Available Em Pedregulho, município do extremo nordeste do Estado de São Paulo, ocorrem fragmentos de cerrado considerados floristicamente distintos dos demais remanescentes paulistas. Nesse estudo, foi realizado um levantamento florístico em Pedregulho, abordando duas regiões geologicamente distintas: o Parque Estadual das Furnas do Bom Jesus e o distrito de Estreito. Em cada uma, delimitaram-se duas parcelas de 50×50 m, totalizando um hectare, onde foram encontradas 65 famílias e 379 espécies de angiospermas. Coletas em áreas adjacentes totalizaram 71 famílias e 443 espécies. As duas regiões estudadas têm baixa similaridade florística entre si. A distribuição geográfica das espécies é analisada e oito padrões são delimitados para aquelas cuja distribuição no Estado de São Paulo é restrita à região de Pedregulho.Pedregulho municipality in the far northeastern region of São Paulo state has fragments of cerrado vegetation thought to be floristically distinct from other cerrado remmants in the state. In this study, a floristic survey was carried out at Pedregulho, focusing on two geologically distinct regions: Furnas do Bom Jesus State Park and the Estreito district. In each region, 50×50 m plots were set up for a total sample area of 1 hectare, where 65 families and 379 angiosperm species were recorded. Collecting efforts in adjacent areas resulted in a total of 71 families and 443 species. The two study areas had low floristic similarity. Geographic species distribution was analyzed and eight patterns were defined for those species restricted to the Pedregulho region in São Paulo.

  13. Causal Loop Analysis of coastal geomorphological systems

    Science.gov (United States)

    Payo, Andres; Hall, Jim W.; French, Jon; Sutherland, James; van Maanen, Barend; Nicholls, Robert J.; Reeve, Dominic E.

    2016-03-01

    As geomorphologists embrace ever more sophisticated theoretical frameworks that shift from simple notions of evolution towards single steady equilibria to recognise the possibility of multiple response pathways and outcomes, morphodynamic modellers are facing the problem of how to keep track of an ever-greater number of system feedbacks. Within coastal geomorphology, capturing these feedbacks is critically important, especially as the focus of activity shifts from reductionist models founded on sediment transport fundamentals to more synthesist ones intended to resolve emergent behaviours at decadal to centennial scales. This paper addresses the challenge of mapping the feedback structure of processes controlling geomorphic system behaviour with reference to illustrative applications of Causal Loop Analysis at two study cases: (1) the erosion-accretion behaviour of graded (mixed) sediment beds, and (2) the local alongshore sediment fluxes of sand-rich shorelines. These case study examples are chosen on account of their central role in the quantitative modelling of geomorphological futures and as they illustrate different types of causation. Causal loop diagrams, a form of directed graph, are used to distil the feedback structure to reveal, in advance of more quantitative modelling, multi-response pathways and multiple outcomes. In the case of graded sediment bed, up to three different outcomes (no response, and two disequilibrium states) can be derived from a simple qualitative stability analysis. For the sand-rich local shoreline behaviour case, two fundamentally different responses of the shoreline (diffusive and anti-diffusive), triggered by small changes of the shoreline cross-shore position, can be inferred purely through analysis of the causal pathways. Explicit depiction of feedback-structure diagrams is beneficial when developing numerical models to explore coastal morphological futures. By explicitly mapping the feedbacks included and neglected within a

  14. Foundational perspectives on causality in large-scale brain networks

    Science.gov (United States)

    Mannino, Michael; Bressler, Steven L.

    2015-12-01

    A profusion of recent work in cognitive neuroscience has been concerned with the endeavor to uncover causal influences in large-scale brain networks. However, despite the fact that many papers give a nod to the important theoretical challenges posed by the concept of causality, this explosion of research has generally not been accompanied by a rigorous conceptual analysis of the nature of causality in the brain. This review provides both a descriptive and prescriptive account of the nature of causality as found within and between large-scale brain networks. In short, it seeks to clarify the concept of causality in large-scale brain networks both philosophically and scientifically. This is accomplished by briefly reviewing the rich philosophical history of work on causality, especially focusing on contributions by David Hume, Immanuel Kant, Bertrand Russell, and Christopher Hitchcock. We go on to discuss the impact that various interpretations of modern physics have had on our understanding of causality. Throughout all this, a central focus is the distinction between theories of deterministic causality (DC), whereby causes uniquely determine their effects, and probabilistic causality (PC), whereby causes change the probability of occurrence of their effects. We argue that, given the topological complexity of its large-scale connectivity, the brain should be considered as a complex system and its causal influences treated as probabilistic in nature. We conclude that PC is well suited for explaining causality in the brain for three reasons: (1) brain causality is often mutual; (2) connectional convergence dictates that only rarely is the activity of one neuronal population uniquely determined by another one; and (3) the causal influences exerted between neuronal populations may not have observable effects. A number of different techniques are currently available to characterize causal influence in the brain. Typically, these techniques quantify the statistical

  15. On asymmetric causal relationships in Petropolitics

    Directory of Open Access Journals (Sweden)

    Balan Feyza

    2016-01-01

    Full Text Available The aim of this paper is to examine whether the First Law of Petropolitics denominated by Friedman in 2006 is valid for OPEC countries. To do this, this paper analyses the relationship between political risk and oil supply by applying the asymmetric panel causality test suggested by Hatemi-J (2011 to these countries for the period 1984-2014. The results show that the First Law of Petropolitics is valid for Angola, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, and the UAE, given that positive oil supply shocks significantly lead to negative political stability shocks, and negative oil supply shocks significantly lead to positive shocks in political stability.

  16. Rapidity Correlation Structures from Causal Hydrodynamics

    CERN Document Server

    Gavin, Sean; Zin, Christopher

    2016-01-01

    Viscous diffusion can broaden the rapidity dependence of two-particle transverse momentum fluctuations. Surprisingly, measurements at RHIC by the STAR collaboration demonstrate that this broadening is accompanied by the appearance of unanticipated structure in the rapidity distribution of these fluctuations in the most central collisions. Although a first order classical Navier-Stokes theory can roughly explain the rapidity broadening, it cannot explain the additional structure. We propose that the rapidity structure can be explained using the second order causal Israel-Stewart hydrodynamics with stochastic noise.

  17. Causality Green functions of bilocal fields

    International Nuclear Information System (INIS)

    It is shown by concrete examples, that the threshold value k-1 = 0 in the field quantum theory with three universal constants c, h, k, proposed in an other work, corresponding to the local theory, constitutes the bifurcation point: the causality Green function by the k finite value bifurcates into two parts: D-tildeLC and D-tildeEC. The Euclidean space-time R4 is a natural carrier of the latter one; its continuation from R4 onto R3.1 is regular, whereas the first one is singular in the zero and on the light cone and therefore it is rejected

  18. Boro, nitrogenio concentraçao de inóculo de pH na expressao da doença causada por Plasmodiophora brassicae

    OpenAIRE

    Schuta, Lucimeris Ruaro

    2013-01-01

    Resumo: A hérnia das cruciferas (Plasmodiophora brassicae Woron.) é a mais importante doença que incide sobre as variedades de Brassica oleracea L. representadas pelo repolho, couve-flor, brócolis, mostarda, couve-chinesa e rúcula. A calagem para elevar o pH dos solos é a medida recomendada mais aceita pelos produtores, contudo, nem sempre esta medida, é suficiente para impedir ou reduzir o ataque do patógeno nos solos da região metropolitana de Curitiba. O que sugere, que outros fatores poss...

  19. As pastagens semeadas anuais biodiversas ricas em leguminosas (PPSBRL), uma emulação da vegetação de Poetea bulbosae

    OpenAIRE

    Aguiar, Carlos; Pires, Jaime; Fernández-Núñez, E.

    2010-01-01

    As PPSBRL caracterizam-se pelo uso de misturas de sementes, muito diversas em espécies/cultivares pratenses anuais melh oradas, entre as quais preponderam leguminosas do género Trifolium. O conceito de PPSBRL deve-se ao agrónomo português David Crespo. A sinecologia e a estrutura florística das PPSBRL e das pastagens de Poetea bulbosae (malhadas) são análogas, entre outros aspecto s, nas exigências bioclimáticas, na dinâmica anual da oferta de biomassa, na sensibilidad...

  20. Trivariate causality between economic growth, urbanisation and electricity consumption in Angola: Cointegration and causality analysis

    International Nuclear Information System (INIS)

    This paper investigates the causal relationship between economic growth, urbanisation and electricity consumption in the case of Angola, while utilizing the data over the period of 1971–2009. We have applied Lee and Strazicich (2003. The Review of Economics and Statistics 63, 1082–1089; 2004. Working Paper. Department of Economics, Appalachian State University) unit root tests to examine the stationarity properties of the series. Using the Gregory–Hansen structural break cointegration procedure as a complement, we employ the ARDL bounds test to investigate long run relationships. The VECM Granger causality test is subsequently used to examine the direction of causality between economic growth, urbanisation, and electricity consumption. Our results indicate the existence of long run relationships. We further observe evidence in favour of bidirectional causality between electricity consumption and economic growth. The feedback hypothesis is also found between urbanisation and economic growth. Urbanisation and electricity consumption Granger cause each other. We conclude that Angola is energy-dependent country. Consequently, the relevant authorities should boost electricity production as one of the means of achieving sustainable economic development in the long run. - Highlights: • We consider the link between electricity consumption and economic growth in Angola. • Urbanisation is added to turn the research into a trivariate investigation. • Various time series procedures are used. • Results show that increasing electricity will improve economic growth in Angola. • Results show urbanisations reduced economic growth during civil war

  1. Interference between Cues Requires a Causal Scenario: Favorable Evidence for Causal Reasoning Models in Learning Processes

    Science.gov (United States)

    Luque, David; Cobos, Pedro L.; Lopez, Francisco J.

    2008-01-01

    In an interference-between-cues design (IbC), the expression of a learned Cue A-Outcome 1 association has been shown to be impaired if another cue, B, is separately paired with the same outcome in a second learning phase. The present study examined whether IbC could be caused by associative mechanisms independent of causal reasoning processes.…

  2. Causal-Explanatory Pluralism: How Intentions, Functions, and Mechanisms Influence Causal Ascriptions

    Science.gov (United States)

    Lombrozo, Tania

    2010-01-01

    Both philosophers and psychologists have argued for the existence of distinct kinds of explanations, including teleological explanations that cite functions or goals, and mechanistic explanations that cite causal mechanisms. Theories of causation, in contrast, have generally been unitary, with dominant theories focusing either on counterfactual…

  3. Causal mechanisms in airfoil-circulation formation

    Science.gov (United States)

    Zhu, J. Y.; Liu, T. S.; Liu, L. Q.; Zou, S. F.; Wu, J. Z.

    2015-12-01

    In this paper, we trace the dynamic origin, rather than any kinematic interpretations, of lift in two-dimensional flow to the physical root of airfoil circulation. We show that the key causal process is the vorticity creation by tangent pressure gradient at the airfoil surface via no-slip condition, of which the theoretical basis has been given by Lighthill ["Introduction: Boundary layer theory," in Laminar Boundary Layers, edited by L. Rosenhead (Clarendon Press, 1963), pp. 46-113], which we further elaborate. This mechanism can be clearly revealed in terms of vorticity formulation but is hidden in conventional momentum formulation, and hence has long been missing in the history of one's efforts to understand lift. By a careful numerical simulation of the flow around a NACA-0012 airfoil, and using both Eulerian and Lagrangian descriptions, we illustrate the detailed transient process by which the airfoil gains its circulation and demonstrate the dominating role of relevant dynamical causal mechanisms at the boundary. In so doing, we find that the various statements for the establishment of Kutta condition in steady inviscid flow actually correspond to a sequence of events in unsteady viscous flow.

  4. Introducing mechanics by tapping core causal knowledge

    International Nuclear Information System (INIS)

    This article concerns an outline of an introductory mechanics course. It is based on the argument that various uses of the concept of force (e.g. from Kepler, Newton and everyday life) share an explanatory strategy based on core causal knowledge. The strategy consists of (a) the idea that a force causes a deviation from how an object would move of its own accord (i.e. its force-free motion), and (b) an incentive to search, where the motion deviates from the assumed force-free motion, for recurring configurations with which such deviations can be correlated (interaction theory). Various assumptions can be made concerning both the force-free motion and the interaction theory, thus giving rise to a variety of specific explanations. Kepler's semi-implicit intuition about the force-free motion is rest, Newton's explicit assumption is uniform rectilinear motion, while in everyday explanations a diversity of pragmatic suggestions can be recognized. The idea is that the explanatory strategy, once made explicit by drawing on students' intuitive causal knowledge, can be made to function for students as an advance organizer, in the sense of a general scheme that they recognize but do not yet know how to detail for scientific purposes

  5. Emergent Horizons and Causal Structures in Holography

    CERN Document Server

    Banerjee, Avik; Kundu, Sandipan

    2016-01-01

    The open string metric arises kinematically in studying fluctuations of open string degrees of freedom on a D-brane. An observer, living on a probe D-brane, can send signals through the spacetime by using such fluctuations on the probe, that propagate in accordance with a metric which is conformal to the open string metric. Event horizons can emerge in the open string metric when one considers a D-brane with an electric field on its worldvolume. Here, we emphasize the role of and investigate, in details, the causal structure of the resulting open string event horizon and demonstrate, among other things, its close similarities to an usual black hole event horizon in asymptotically AdS-spaces. To that end, we analyze relevant geodesics, Penrose diagrams and various causal holographic observables for a given open string metric. For analytical control, most of our calculations are performed in an asymptotically AdS$_3$-background, however, we argue that the physics is qualitatively the same in higher dimensions. ...

  6. Diagnostic reasoning using qualitative causal models

    International Nuclear Information System (INIS)

    The application of expert systems to reasoning problems involving real-time data from plant measurements has been a topic of much research, but few practical systems have been deployed. One obstacle to wider use of expert systems in applications involving real-time data is the lack of adequate knowledge representation methodologies for dynamic processes. Knowledge bases composed mainly of rules have disadvantages when applied to dynamic processes and real-time data. This paper describes a methodology for the development of qualitative causal models that can be used as knowledge bases for reasoning about process dynamic behavior. These models provide a systematic method for knowledge base construction, considerably reducing the engineering effort required. They also offer much better opportunities for verification and validation of the knowledge base, thus increasing the possibility of the application of expert systems to reasoning about mission critical systems. Starting with the Signed Directed Graph (SDG) method that has been successfully applied to describe the behavior of diverse dynamic processes, the paper shows how certain non-physical behaviors that result from abstraction may be eliminated by applying causal constraint to the models. The resulting Extended Signed Directed Graph (ESDG) may then be compiled to produce a model for use in process fault diagnosis. This model based reasoning methodology is used in the MOBIAS system being developed by Duke Power Company under EPRI sponsorship. 15 refs., 4 figs

  7. EEG oscillations: From correlation to causality.

    Science.gov (United States)

    Herrmann, Christoph S; Strüber, Daniel; Helfrich, Randolph F; Engel, Andreas K

    2016-05-01

    Already in his first report on the discovery of the human EEG in 1929, Berger showed great interest in further elucidating the functional roles of the alpha and beta waves for normal mental activities. Meanwhile, most cognitive processes have been linked to at least one of the traditional frequency bands in the delta, theta, alpha, beta, and gamma range. Although the existing wealth of high-quality correlative EEG data led many researchers to the conviction that brain oscillations subserve various sensory and cognitive processes, a causal role can only be demonstrated by directly modulating such oscillatory signals. In this review, we highlight several methods to selectively modulate neuronal oscillations, including EEG-neurofeedback, rhythmic sensory stimulation, repetitive transcranial magnetic stimulation (rTMS), and transcranial alternating current stimulation (tACS). In particular, we discuss tACS as the most recent technique to directly modulate oscillatory brain activity. Such studies demonstrating the effectiveness of tACS comprise reports on purely behavioral or purely electrophysiological effects, on combination of behavioral effects with offline EEG measurements or on simultaneous (online) tACS-EEG recordings. Whereas most tACS studies are designed to modulate ongoing rhythmic brain activity at a specific frequency, recent evidence suggests that tACS may also modulate cross-frequency interactions. Taken together, the modulation of neuronal oscillations allows to demonstrate causal links between brain oscillations and cognitive processes and to obtain important insights into human brain function. PMID:25659527

  8. Evidence for online processing during causal learning.

    Science.gov (United States)

    Liu, Pei-Pei; Luhmann, Christian C

    2015-03-01

    Many models of learning describe both the end product of learning (e.g., causal judgments) and the cognitive mechanisms that unfold on a trial-by-trial basis. However, the methods employed in the literature typically provide only indirect evidence about the unfolding cognitive processes. Here, we utilized a simultaneous secondary task to measure cognitive processing during a straightforward causal-learning task. The results from three experiments demonstrated that covariation information is not subject to uniform cognitive processing. Instead, we observed systematic variation in the processing dedicated to individual pieces of covariation information. In particular, observations that are inconsistent with previously presented covariation information appear to elicit greater cognitive processing than do observations that are consistent with previously presented covariation information. In addition, the degree of cognitive processing appears to be driven by learning per se, rather than by nonlearning processes such as memory and attention. Overall, these findings suggest that monitoring learning processes at a finer level may provide useful psychological insights into the nature of learning. PMID:25488021

  9. Causal Conclusions that Flip Repeatedly and Their Justification

    CERN Document Server

    Kelly, Kevin T

    2012-01-01

    Over the past two decades, several consis- tent procedures have been designed to infer causal conclusions from observational data. We prove that if the true causal network might be an arbitrary, linear Gaussian net- work or a discrete Bayes network, then every unambiguous causal conclusion produced by a consistent method from non-experimental data is subject to reversal as the sample size increases any finite number of times. That result, called the causal flipping theorem, ex- tends prior results to the effect that causal discovery cannot be reliable on a given sam- ple size. We argue that since repeated flipping of causal conclusions is unavoidable in principle for consistent methods, the best possible discovery methods are consistent methods that retract their earlier conclusions no more than necessary. A series of sim- ulations of various methods across a wide range of sample sizes illustrates concretely both the theorem and the principle of com- paring methods in terms of retractions.

  10. Comparison Analysis: Granger Causality and New Causality and Their Applications to Motor Imagery.

    Science.gov (United States)

    Hu, Sanqing; Wang, Hui; Zhang, Jianhai; Kong, Wanzeng; Cao, Yu; Kozma, Robert

    2016-07-01

    In this paper we first point out a fatal drawback that the widely used Granger causality (GC) needs to estimate the autoregressive model, which is equivalent to taking a series of backward recursive operations which are infeasible in many irreversible chemical reaction models. Thus, new causality (NC) proposed by Hu et al. (2011) is theoretically shown to be more sensitive to reveal true causality than GC. We then apply GC and NC to motor imagery (MI) which is an important mental process in cognitive neuroscience and psychology and has received growing attention for a long time. We study causality flow during MI using scalp electroencephalograms from nine subjects in Brain-computer interface competition IV held in 2008. We are interested in three regions: Cz (central area of the cerebral cortex), C3 (left area of the cerebral cortex), and C4 (right area of the cerebral cortex) which are considered to be optimal locations for recognizing MI states in the literature. Our results show that: 1) there is strong directional connectivity from Cz to C3/C4 during left- and right-hand MIs based on GC and NC; 2) during left-hand MI, there is directional connectivity from C4 to C3 based on GC and NC; 3) during right-hand MI, there is strong directional connectivity from C3 to C4 which is much clearly revealed by NC than by GC, i.e., NC largely improves the classification rate; and 4) NC is demonstrated to be much more sensitive to reveal causal influence between different brain regions than GC. PMID:26099149

  11. On the causal structure between CO2 and global temperature

    OpenAIRE

    Adolf Stips; Diego Macias; Clare Coughlan; Elisa Garcia-Gorriz; X. San Liang

    2016-01-01

    We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aeroso...

  12. Non-parametric causal inference for bivariate time series

    CERN Document Server

    McCracken, James M

    2015-01-01

    We introduce new quantities for exploratory causal inference between bivariate time series. The quantities, called penchants and leanings, are computationally straightforward to apply, follow directly from assumptions of probabilistic causality, do not depend on any assumed models for the time series generating process, and do not rely on any embedding procedures; these features may provide a clearer interpretation of the results than those from existing time series causality tools. The penchant and leaning are computed based on a structured method for computing probabilities.

  13. Finance and Growth: Institutional Considerations, Financial Policies and Causality

    OpenAIRE

    Philip Arestis; Panicos Demetriades

    1999-01-01

    Authors in this article suggest that country specific institutional factors and policies are likely to influence the causal nature of the relationship between financial development and economic growth. Authors conduct cointegration and causality tests using time series data for twelve representative countries. The empirical results show considerable variation of causality across countries which can be explained by institutional and policy differences, providing support to the main hypothesis.

  14. Causality, Unintended Consequences and Deducing Shared Causes

    OpenAIRE

    Steven M. Shugan

    2007-01-01

    Despite warnings against inferring causality from observed correlations or statistical dependence, some articles do. Observed correlation is neither necessary nor sufficient to infer causality as defined by the term's everyday usage. For example, a deterministic causal process creates pseudorandom numbers; yet, we observe no correlation between the numbers. Child height correlates with spelling ability because age causes both. Moreover, order is problematic—we hear train whistles before obser...

  15. Dark matter perturbations and viscosity: a causal approach

    OpenAIRE

    Acquaviva, Giovanni; John, Anslyn; Pénin, Aurélie

    2016-01-01

    The inclusion of dissipative effects in cosmic fluids modifies their clustering properties and could have observable effects on the formation of large scale structures. We analyse the evolution of density perturbations of cold dark matter endowed with causal bulk viscosity. The perturbative analysis is carried out in the Newtonian approximation and the bulk viscosity is described by the causal Israel-Stewart (IS) theory. In contrast to the non-causal Eckart theory, we obtain a third order evo...

  16. The Causality between Government Revenue and Government Expenditure in Iran

    OpenAIRE

    2012-01-01

    The causal relationship between government revenue and government expenditure is an important subject in public economics especially to the control of budget deficit. The purpose of this study is to investigate the relationship between government revenue and government expenditure in Iran by applying the bounds testing approach to cointegration. The results of the causality test show that there is a bidirectional causal relationship between government expenditure and revenues in both long run...

  17. Integrating Probabilistic, Taxonomic and Causal Knowledge in Abductive Diagnosis

    OpenAIRE

    Lin, Dekang; Goebel, Randy

    2013-01-01

    We propose an abductive diagnosis theory that integrates probabilistic, causal and taxonomic knowledge. Probabilistic knowledge allows us to select the most likely explanation; causal knowledge allows us to make reasonable independence assumptions; taxonomic knowledge allows causation to be modeled at different levels of detail, and allows observations be described in different levels of precision. Unlike most other approaches where a causal explanation is a hypothesis that one or more causat...

  18. A general, multivariate definition of causal effects in epidemiology.

    Science.gov (United States)

    Flanders, W Dana; Klein, Mitchel

    2015-07-01

    Population causal effects are often defined as contrasts of average individual-level counterfactual outcomes, comparing different exposure levels. Common examples include causal risk difference and risk ratios. These and most other examples emphasize effects on disease onset, a reflection of the usual epidemiological interest in disease occurrence. Exposure effects on other health characteristics, such as prevalence or conditional risk of a particular disability, can be important as well, but contrasts involving these other measures may often be dismissed as non-causal. For example, an observed prevalence ratio might often viewed as an estimator of a causal incidence ratio and hence subject to bias. In this manuscript, we provide and evaluate a definition of causal effects that generalizes those previously available. A key part of the generalization is that contrasts used in the definition can involve multivariate, counterfactual outcomes, rather than only univariate outcomes. An important consequence of our generalization is that, using it, one can properly define causal effects based on a wide variety of additional measures. Examples include causal prevalence ratios and differences and causal conditional risk ratios and differences. We illustrate how these additional measures can be useful, natural, easily estimated, and of public health importance. Furthermore, we discuss conditions for valid estimation of each type of causal effect, and how improper interpretation or inferences for the wrong target population can be sources of bias. PMID:25946227

  19. Causal topology in future and past distinguishing spacetimes

    International Nuclear Information System (INIS)

    The causal structure of a strongly causal spacetime is particularly well endowed. Not only does it determine the conformal spacetime geometry when the spacetime dimension n > 2, as shown by Malament and Hawking-King-McCarthy (MHKM), but also the manifold dimension. The MHKM result, however, applies more generally to spacetimes satisfying the weaker causality condition of future and past distinguishability (FPD), and it is an important question whether the causal structure of such spacetimes can determine the manifold dimension. In this work, we show that the answer to this question is in the affirmative. We investigate the properties of future or past distinguishing spacetimes and show that their causal structures determine the manifold dimension. This gives a non-trivial generalization of the MHKM theorem and suggests that there is a causal topology for FPD spacetimes which encodes manifold dimension and which is strictly finer than the Alexandrov topology. We show that such a causal topology does exist. We construct it using a convergence criterion based on sequences of 'chain intervals' which are the causal analogues of null geodesic segments. We show that when the region of strong causality violation satisfies a local achronality condition, this topology is equivalent to the manifold topology in an FPD spacetime.

  20. Comparação florística e estrutural de duas florestas de várzea no estuário amazônico, Pará, Brasil

    OpenAIRE

    Fábio de Jesus Batista; Mário Augusto Gonçalves Jardim; Tonny David Santiago Medeiros; Isaac Luiz Magalhães Lopes

    2011-01-01

    O objetivo deste trabalho foi conhecer e comparar a composição florística e a estrutura de duas áreas de florestas de várzea localizadas na reserva extrativista Chocoaré-Mato Grosso, Santarém Novo-PA. O inventário florístico abrangeu 1,5 ha em parcelas de 10 x 100 m, distribuídas na área 1 (1,0 ha) e área 2 (0,5 ha). Foram identificados os indivíduos arbóreos com circunferência a 1,3 m altura do solo (CAP > 30 cm e demonstrada a riqueza, área basal e o IVI (Índice de Valor de Importância) par...

  1. Causality and stability of cosmic jets

    Science.gov (United States)

    Porth, Oliver; Komissarov, Serguei S.

    2015-09-01

    In stark contrast to their laboratory and terrestrial counterparts, cosmic jets appear to be very stable. They are able to penetrate vast spaces, which exceed by up to a billion times the size of their central engines. We propose that the reason behind this remarkable property is the loss of causal connectivity across these jets, caused by their rapid expansion in response to fast decline of external pressure with the distance from the `jet engine'. In atmospheres with power-law pressure distribution, pext ∝ z-κ, the total loss of causal connectivity occurs, when κ > 2 - the steepness which is expected to be quite common for many astrophysical environments. This conclusion does not seem to depend on the physical nature of jets - it applies both to relativistic and non-relativistic flows, both magnetically dominated and unmagnetized jets. In order to verify it, we have carried out numerical simulations of moderately magnetized and moderately relativistic jets. The results give strong support to our hypothesis and provide with valuable insights. In particular, we find that the z-pinched inner cores of magnetic jets expand slower than their envelopes and become susceptible to instabilities even when the whole jet is stable. This may result in local dissipation and emission without global disintegration of the flow. Cosmic jets may become globally unstable when they enter flat sections of external atmospheres. We propose that the Fanaroff-Riley (FR) morphological division of extragalactic radio sources into two classes is related to this issue. In particular, we argue that the low power FR-I jets become reconfined, causally connected and globally unstable on the scale of galactic X-ray coronas, whereas more powerful FR-II jets reconfine much further out, already on the scale of radio lobes and remain largely intact until they terminate at hotspots. Using this idea, we derived the relationship between the critical jet power and the optical luminosity of the host

  2. Quantum causality, stochastics, trajectories and information

    International Nuclear Information System (INIS)

    A history of the discovery of 'new' quantum mechanics and the paradoxes of its probabilistic interpretation are briefly reviewed from the modern point of view of quantum probability and information. Modern quantum theory, which has been developed during the last 20 years for the treatment of quantum open systems including quantum noise, decoherence, quantum diffusions and spontaneous jumps occurring under continuous in time observation, is not yet a part of the standard curriculum of quantum physics. It is argued that the conventional formalism of quantum mechanics is insufficient for the description of quantum events, such as spontaneous decays say, and the new experimental phenomena related to individual quantum measurements, but they have all received an adequate mathematical treatment in quantum stochastics of open systems. Moreover, the only reasonable probabilistic interpretation of quantum mechanics put forward by Max Born was, in fact, in irreconcilable contradiction with traditional mechanical reality and causality. This led to numerous quantum paradoxes, some of them due to the great inventors of quantum theory such as Einstein and Schroedinger. They are reconsidered in this paper from the modern point of view of quantum stochastics and information. The development of quantum measurement theory, initiated by von Neumann, indicated a possibility for resolution of this interpretational crisis by divorcing the algebra of the dynamical generators and the algebra of the actual observables, or Bell's beables. It is shown that within this approach quantum causality can be rehabilitated in the form of a superselection rule for compatibility of the actual histories with the potential future. This rule, together with the self-compatibility of the measurements ensuring the consistency of the histories, is called the nondemolition, or causality principle in modern quantum theory. The application of this rule in the form of dynamical commutation relations leads to the

  3. Libertad de la voluntad y poderes causales Freedom of the will and causal powers

    Directory of Open Access Journals (Sweden)

    JOSÉ TOMÁS ALVARADO MARAMBIO

    2012-03-01

    Full Text Available Este trabajo discute una objeción bien conocida a la libertad de la voluntad libertaria en un mundo no determinista. En un mundo no determinista el estado de cosas total del mundo en un instante de tiempo t es compatible con diferentes estados de cosas totales alternativos en el futuro de t. Se ha argumentado que, en cuanto son posibles diferentes alternativas a una decisión libre, es una cuestión de azar y suerte que tal decisión se ha tomado. Si una decisión libre es una cuestión de suerte, entonces el agente no puede ser considerado responsable por ella. Se argumenta que la dificultad aparece en una concepción anti-realista de la causalidad, donde los hechos causales son supervenientes a regularidades o dependencias contrafácticas. Una concepción realista de la causalidad puede, por ello, explicar cómo el agente está en control causal de la decisión libre tomada, cuando la decisión no cae bajo una regularidad o una dependencia contrafáctica. Una vez considerado cómo es que el agente está en control de la decisión, se argumenta que no se puede decir que la decisión libre es una cuestión de suerte para el agente.This paper discusses a well-known objection to libertarian free will in a non-deterministic world. In a non-deterministic world the complete state of affairs of the world in an instant of time t is compatible with different alternative complete states of affairs in the future of t. It has been argued that, in so far as different alternatives are possible to a free decision, it is a matter of chance and luck that that decision is taken. If a free decision is a matter of luck, then the agent cannot be considered responsible for it. It is argued that the difficulty appears from an anti-realist conception of causality, where causal facts are supervenient on regularities or counterfactual dependences. A realist conception of causality can, then, explain how the agent is causally in control of the free decision taken when

  4. Causality and hyperbolicity of Lovelock theories

    International Nuclear Information System (INIS)

    In Lovelock theories, gravity can travel faster or slower than light. The causal structure is determined by the characteristic hypersurfaces. We generalize a recent result of Izumi to prove that any Killing horizon is a characteristic hypersurface for all gravitational degrees of freedom of a Lovelock theory. Hence gravitational signals cannot escape from the region inside such a horizon. We investigate the hyperbolicity of Lovelock theories by determining the characteristic hypersurfaces for various backgrounds. First we consider Ricci flat type N spacetimes. We show that characteristic hypersurfaces are generically all non-null and that Lovelock theories are hyperbolic in any such spacetime. Next we consider static, maximally symmetric black hole solutions of Lovelock theories. Again, characteristic surfaces are generically non-null. For some small black holes, hyperbolicity is violated near the horizon. This implies that the stability of such black holes is not a well-posed problem. (paper)

  5. On the Causal Set-Continuum Correspondence

    CERN Document Server

    Saravani, Mehdi

    2014-01-01

    We present two results which concern certain aspects of the question: when is a causal set well approximated by a Lorentzian manifold? The first result is a theorem which shows that the number-volume correspondence, if required to hold even for arbitrarily small regions, is best realized via Poisson sprinkling. The second result concerns a family of lattices in $1+1$ dimensional Minkowski space, known as Lorentzian lattices, which we show provide a much better number-volume correspondence than Poisson sprinkling for large volumes. We argue, however, that this feature should not persist in higher dimensions. We conclude by conjecturing a form of the aforementioned theorem that holds under weaker assumptions, namely that Poisson sprinkling provides the best number-volume correspondence in $3+1$ dimensions for spacetime regions with macroscopically large volumes.

  6. Wiretap Channel with Causal State Information

    CERN Document Server

    Chia, Yeow-Khiang

    2010-01-01

    A lower bound on the secrecy capacity of the wiretap channel with state information available causally at both the encoder and decoder is established. The lower bound is shown to be strictly larger than that for the noncausal case by Liu and Chen. Achievability is proved using block Markov coding, Shannon strategy, and key generation from common state information. The state sequence available at the end of each block is used to generate a key, which is used to enhance the transmission rate of the confidential message in the following block. An upper bound on the secrecy capacity when the state is available noncausally at the encoder and decoder is established and is shown to coincide with the lower bound for several classes of wiretap channels with state.

  7. Causality Constraints in Conformal Field Theory

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂φ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinni...

  8. Equity Theory Ratios as Causal Schemas

    Science.gov (United States)

    Arvanitis, Alexios; Hantzi, Alexandra

    2016-01-01

    Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes.

  9. Exploring Torus Universes in Causal Dynamical Triangulations

    CERN Document Server

    Budd, T G

    2013-01-01

    Motivated by the search for new observables in nonperturbative quantum gravity, we consider Causal Dynamical Triangulations (CDT) in 2+1 dimensions with the spatial topology of a torus. This system is of particular interest, because one can study not only the global scale factor, but also global shape variables in the presence of arbitrary quantum fluctuations of the geometry. Our initial investigation focusses on the dynamics of the scale factor and uncovers a qualitatively new behaviour, which leads us to investigate a novel type of boundary conditions for the path integral. Comparing large-scale features of the emergent quantum geometry in numerical simulations with a classical minisuperspace formulation, we find partial agreement. By measuring the correlation matrix of volume fluctuations we succeed in reconstructing the effective action for the scale factor directly from the simulation data. Apart from setting the stage for the analysis of shape dynamics on the torus, the new set-up highlights the role o...

  10. Causality constraints in conformal field theory

    Science.gov (United States)

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan

    2016-05-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂ ϕ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators.

  11. A study in cosmology and causal thermodynamics

    International Nuclear Information System (INIS)

    The especial relativity of thermodynamic theories for reversible and irreversible processes in continuous medium is studied. The formalism referring to equilibrium and non-equilibrium configurations, and theories which includes the presence of gravitational fields are discussed. The nebular model in contraction with dissipative processes identified by heat flux and volumetric viscosity is thermodymically analysed. This model is presented by a plane conformal metric. The temperature, pressure, entropy and entropy production within thermodynamic formalism which adopts the hypothesis of local equilibrium, is calculated. The same analysis is carried out considering a causal thermodynamics, which establishes a local entropy of non-equilibrium. Possible homogeneous and isotropic cosmological models, considering the new phenomenological equation for volumetric viscosity deriving from cause thermodynamics are investigated. The found out models have plane spatial section (K=0) and some ones do not have singularities. The energy conditions are verified and the entropy production for physically reasobable models are calculated. (M.C.K.)

  12. Causality and local determinism versus quantum nonlocality

    CERN Document Server

    Kupczynski, Marian

    2013-01-01

    The entanglement and the violation of Bell and CHSH inequalities in spin polarization correlation experiments (SPCE) is considered to be one of the biggest mysteries of Nature and is called quantum nonlocality. In this paper we show once again that this conclusion is based on imprecise terminology and on the lack of understanding of probabilistic models used in various proofs of Bell and CHSH theorems. These models are inconsistent with experimental protocols used in SPCE. This is the only reason why Bell and CHSH inequalities are violated. A probabilistic non-signalling description of SPCE, consistent with quantum predictions, is possible and it depends explicitly on the context of each experiment. It is also deterministic in the sense that the outcome is determined by supplementary local parameters describing both a physical signals and measuring instruments. The existence of such description gives additional arguments that quantum theory is emergent from some more detailed theory respecting causality and l...

  13. Causality Constraints in Conformal Field Theory

    CERN Document Server

    Hartman, Thomas; Kundu, Sandipan

    2015-01-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the $(\\partial\\phi)^4$ coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning o...

  14. Levantamento florístico das tribos Psychotrieae, Coussareeae e Morindeae (Rubiaceae na região de Porto Rico, alto rio Paraná - DOI: 10.4025/actascibiolsci.v20i0.4474 Flora survey of tribes Psychotrieae, Coussareeae and Morindeae in the region of Porto Rico, high river Paraná - DOI: 10.4025/actascibiolsci.v20i0.4474

    Directory of Open Access Journals (Sweden)

    Maria Conceição de Souza

    1998-07-01

    Full Text Available A elevada diversidade florística das regiões tropicais torna-as importantes na busca de novas fontes fitoterápicas e alimentícias, fazendo dos levantamentos florísticos importantes estudos para a ampliação do conhecimento dessa fitodiversidade. Este trabalho foi elaborado buscando ampliar o conhecimento da flora do alto rio Paraná, em especial das tribos Psychotrieae, Coussareeae e Morindeae da família Rubiaceae. A área deste estudo localiza-se a aproximadamente 22º41’-22º51’S e 53º12’-53º28’W, abrangendo parte dos Estados do Paraná e do Mato Grosso do Sul. Coletas de material botânico foram realizadas durante os anos de 1992 a 1995, tendo sido elaboradas chaves de identificação, descrições e ilustrações das espécies. Foram levantados quatro gêneros e seis espécies, Palicourea (P. crocea, Psychotria (P. carthagenensis e P. leiocarpa, Coussarea (C. contracta e C. platyphylla e Cephalanthus (C. glabratus.The great diversity of flora in tropical regions transforms them into very important food and phytotherapy sources. Flora surveys are indispensable for a profounder knowledge of this biodiversity. Research work aimed at improving knowledge on the flora of the high river Paraná with special emphasis to the tribes Psychotrieae, Coussareeae and Morindeae. The area lies in the states of Paraná and Mato Grosso do Sul at 22º41’-22º51’S and 53º12’-53º28’W. Botanic samplings were carried out from 1992 to 1995 and species identification keys, description and illustrations were elaborated. Four genera and six species were surveyed, or rather, Palicourea (P. crocea, Psychotria (P. carthagenensis and P. leiocarpa, Coussarea (C. contracta and C. platyphylla and Cephalanthus (C. glabratus.

  15. The balanced survivor average causal effect.

    Science.gov (United States)

    Greene, Tom; Joffe, Marshall; Hu, Bo; Li, Liang; Boucher, Ken

    2013-01-01

    Statistical analysis of longitudinal outcomes is often complicated by the absence of observable values in patients who die prior to their scheduled measurement. In such cases, the longitudinal data are said to be "truncated by death" to emphasize that the longitudinal measurements are not simply missing, but are undefined after death. Recently, the truncation by death problem has been investigated using the framework of principal stratification to define the target estimand as the survivor average causal effect (SACE), which in the context of a two-group randomized clinical trial is the mean difference in the longitudinal outcome between the treatment and control groups for the principal stratum of always-survivors. The SACE is not identified without untestable assumptions. These assumptions have often been formulated in terms of a monotonicity constraint requiring that the treatment does not reduce survival in any patient, in conjunction with assumed values for mean differences in the longitudinal outcome between certain principal strata. In this paper, we introduce an alternative estimand, the balanced-SACE, which is defined as the average causal effect on the longitudinal outcome in a particular subset of the always-survivors that is balanced with respect to the potential survival times under the treatment and control. We propose a simple estimator of the balanced-SACE that compares the longitudinal outcomes between equivalent fractions of the longest surviving patients between the treatment and control groups and does not require a monotonicity assumption. We provide expressions for the large sample bias of the estimator, along with sensitivity analyses and strategies to minimize this bias. We consider statistical inference under a bootstrap resampling procedure. PMID:23658214

  16. Recursive partitioning for heterogeneous causal effects.

    Science.gov (United States)

    Athey, Susan; Imbens, Guido

    2016-07-01

    In this paper we propose methods for estimating heterogeneity in causal effects in experimental and observational studies and for conducting hypothesis tests about the magnitude of differences in treatment effects across subsets of the population. We provide a data-driven approach to partition the data into subpopulations that differ in the magnitude of their treatment effects. The approach enables the construction of valid confidence intervals for treatment effects, even with many covariates relative to the sample size, and without "sparsity" assumptions. We propose an "honest" approach to estimation, whereby one sample is used to construct the partition and another to estimate treatment effects for each subpopulation. Our approach builds on regression tree methods, modified to optimize for goodness of fit in treatment effects and to account for honest estimation. Our model selection criterion anticipates that bias will be eliminated by honest estimation and also accounts for the effect of making additional splits on the variance of treatment effect estimates within each subpopulation. We address the challenge that the "ground truth" for a causal effect is not observed for any individual unit, so that standard approaches to cross-validation must be modified. Through a simulation study, we show that for our preferred method honest estimation results in nominal coverage for 90% confidence intervals, whereas coverage ranges between 74% and 84% for nonhonest approaches. Honest estimation requires estimating the model with a smaller sample size; the cost in terms of mean squared error of treatment effects for our preferred method ranges between 7-22%. PMID:27382149

  17. World oil and agricultural commodity prices: Evidence from nonlinear causality

    International Nuclear Information System (INIS)

    The increasing co-movements between the world oil and agricultural commodity prices have renewed interest in determining price transmission from oil prices to those of agricultural commodities. This study extends the literature on the oil-agricultural commodity prices nexus, which particularly concentrates on nonlinear causal relationships between the world oil and three key agricultural commodity prices (corn, soybeans, and wheat). To this end, the linear causality approach of Toda-Yamamoto and the nonparametric causality method of Diks-Panchenko are applied to the weekly data spanning from 1994 to 2010. The linear causality analysis indicates that the oil prices and the agricultural commodity prices do not influence each other, which supports evidence on the neutrality hypothesis. In contrast, the nonlinear causality analysis shows that: (i) there are nonlinear feedbacks between the oil and the agricultural prices, and (ii) there is a persistent unidirectional nonlinear causality running from the oil prices to the corn and to the soybeans prices. The findings from the nonlinear causality analysis therefore provide clues for better understanding the recent dynamics of the agricultural commodity prices and some policy implications for policy makers, farmers, and global investors. This study also suggests the directions for future studies. - Research highlights: → This study determines the price transmission mechanisms between the world oil and three key agricultural commodity prices (corn, soybeans, and wheat). → The linear and nonlinear cointegration and causality methods are carried out. → The linear causality analysis supports evidence on the neutrality hypothesis. → The nonlinear causality analysis shows that there is a persistent unidirectional causality from the oil prices to the corn and to the soybeans prices.

  18. The Dynamic Causal Relationship between Electricity Consumption and Economic Growth in Ghana: A Trivariate Causality Model

    Directory of Open Access Journals (Sweden)

    Bernard N. Iyke

    2014-06-01

    Full Text Available This paper examines the dynamic causal relationship between electricity consumption and economic growth in Ghana within a trivariate ARDL framework, for the period 1971–2012.The paper obviates the variable omission bias, and the use of cross-sectional techniques that characterise most existing studies. The results show that there is a distinct causal flow from economic growth to electricity consumption: both in the short run and in the long run. This finding supports the growth-led electricity consumption hypothesis, as documented in the literature. The paper urges policymakers in Ghana to resort to alternative sources of electric power generation, in order to reduce any future pressures on the current sources of electricity production. Appropriate monetary policies must also be put in place, in order to accommodate potential inflation hikes stemming from excessive demands for electricity in the near future.

  19. Influência da sacarose e do corte da base da haste na longevidade de inflorescências de Zinnia elegans

    Directory of Open Access Journals (Sweden)

    Carneiro Tânia Forster

    2002-01-01

    Full Text Available Flores de zínia (Zinnia elegans Jacq. são adaptadas às condições climáticas da Região Sudeste do País, com excelente potencial para a comercialização como flor de corte. O presente trabalho objetivou avaliar a influência da sacarose aplicada na forma de solução de condicionamento, e do corte periódico da base das hastes sobre a longevidade e absorção de água pelas flores. Hastes florais uniformizadas em tamanho foram submetidas ao condicionamento, por seis horas, com sacarose a 5, 10, 15 e 20% ou com soluções de 10% de sacarose por 0, 6, 12, 18 e 24 horas, com ou sem cortes periódicos na base das hastes a cada 48 horas. O tratamento das flores por seis horas com sacarose a 5, 10, 15 ou 20% não afetou a longevidade das flores, comparado àquelas mantidas somente com água destilada. O corte periódico da base das hastes promoveu melhor suprimento de água às flores, estendendo a longevidade. O condicionamento das flores com 10% de sacarose por 18 ou 24 horas acelerou a senescência das flores em vaso. A taxa de produção de etileno foi inibida pelo aumento da concentração de sacarose na solução de condicionamento.

  20. Fitossociologia e similaridade florística entre trechos de Cerrado sentido restrito em interflúvio e em vale no Jardim Botânico de Brasília, DF Phytossociology and floristic similarity between plateau and valley `Cerrado` woody vegetation in the Brasília Botanic Gardens, Federal District, Brazil

    Directory of Open Access Journals (Sweden)

    Mônica Souza da Fonseca

    2004-03-01

    Full Text Available Este estudo teve como objetivo verificar a composição florística, densidade e área basal do componente lenhoso do cerrado sentido restrito em duas situações num gradiente topográfico, designadas interflúvio (I e vale (V, no Jardim Botânico de Brasília, DF. Foram alocadas em cada área 10 parcelas permanentes de 20x50m para amostragem de todos os indivíduos com diâmetro basal DB(30cm> 5cm. A classificação por UPGMA (Índices de Sørensen e Morisita foi usada para a avaliação da similaridade entre parcelas. A análise da fitossociologia mostrou que as espécies mais importantes no interflúvio foram: Ouratea hexasperma (A. St.Hil Baill., Miconia ferruginata DC. e Dalbergia miscolobium Benth., enquanto que no vale foram: Eriotheca pubescens (Mart. & Zucc. Schott & Endl., Ouratea hexasperma (A. St.-Hil. Baill. e Schefflera macrocarpa (Seem D.C. Frodin. Os índices de similaridade variaram entre 0,26 a 0,81 (Sørensen e 0,06 a 0,92 (Morisita. A classificação por UPGMA indicou dois grupos principais, que coincidiram com as posições no relevo: interflúvio e vale. Os resultados salientaram a topografia como forte determinante na distribuição de algumas das populações e comunidades lenhosas, por meio de sua influência na variação da profundidade do lençol freático, que afetou a composição florística, a densidade (I/V=1.219/956 ind.ha-1 e a área basal (I/V=8,56/5,64m².ha-1 nos Cerrados sentido restrito de interflúvio (I e vale (V estudados.This study aims to check differences in the floristic composition and structure of the woody vegetation of the cerrado (sensu stricto in two distinct topographic positions, Interfluve (I and Valley Slope (V area in the Brasília Botanic Gardens, Federal District, Brazil. In each area ten 20x50m permanent plots were located to survey individuals, basal diameter BD(30cm > 5cm. UPGMA classification (Sørensen and Morisita similarity indices was used to assess similarity among plots

  1. Alienígenas na sala: o que fazer com espécies exóticas em trabalhos de taxonomia, florística e fitossociologia? Aliens in the room: what to do with exotic species in taxonomic, floristic and phytosociological studies?

    Directory of Open Access Journals (Sweden)

    Marcelo Freire Moro

    2012-12-01

    Full Text Available A presença cada vez mais disseminada de organismos exóticos (muitos dos quais se tornam invasores nas diferentes regiões do planeta levou ao surgimento de uma linha de pesquisa na ecologia voltada às invasões biológicas. E para permitir a comunicação entre autores também foi desenvolvido um arcabouço terminológico. Mas, apesar disso, a terminologia relativa às bioinvasões tem sido ignorada por boa parte dos botânicos no Brasil. Há uma boa dose de confusão entre botânicos sobre o que seja uma espécie exótica, naturalizada, invasora, daninha e ruderal, levando ao uso inconsistente da terminologia. Além disso, diferentes autores têm adotado posturas praticamente opostas ao lidar com espécies exóticas em suas áreas de estudo, seja na preparação de tratamentos taxonômicos, seja na publicação de levantamentos florísticos e fitossociológicos. Enquanto alguns pesquisadores incluem em floras mesmo espécies cultivadas que não se reproduzem, outros excluem plantas invasoras comuns e conspícuas. Nós apresentamos aqui, em português, os principais conceitos relativos ao tema da bioinvasão e chamamos a atenção dos autores brasileiros para a necessidade de utilizar de modo consistente o arcabouço terminológico já existente na literatura. Também propomos a adoção de rótulos claros para informar quais espécies são exóticas na área estudada, diferenciando-as das nativas, e sugerimos critérios para ajudar botânicos a decidirem quando uma planta exótica deve ou não ser incluída em tratamentos taxonômicos ou levantamentos de florística.The ever-growing presence of exotic organisms (many of which become invasive throughout the planet has led to the emergence of biological invasions as a field of study within ecology. To enable communication between scientists in this field, a terminology has developed. However, this terminology has been ignored by many botanists in Brazil where there is confusion regarding

  2. Jungermanniales (Marchantiophyta) da Chapada da Ibiapaba, Ceará, Brasil Jungermanniales (Marchantiophyta) of the Ibiapaba Plateau, Ceará state, Brazil

    OpenAIRE

    Hermeson Cassiano de Oliveira; Cid José Passos Bastos

    2009-01-01

    A Chapada da Ibiapaba, localiza-se ao norte do estado do Ceará, possuindo uma extensão de 110 km com alitudes variando entre 800 e 1100 m. No inventário florístico de briófitas realizado na área, foram encontradas 15 espécies de hepáticas folhosas, pertencentes a odaem Jungermanniales, distribuídas em oito gêneros e seis famílias. Das espécies encontradas, cinco representam novos registros para o estado do Ceará e quatro para a região Nordeste. Chiloscyphus serratus (Mitt.) J.J. Engel & R.M. ...

  3. Avaliação do potencial biológico da Tabebuia aurea(Silva Manso como fonte de moléculas bioativas para atividade antimicrobiana, antiedematogênica e antirradicalar

    Directory of Open Access Journals (Sweden)

    R.F.E.P. SANTOS

    2015-01-01

    Full Text Available RESUMO As espécies da família Bignoniaceae e do gênero Tabebuia são amplamente utilizadas na medicina tradicional e possuem um forte potencial terapêutico. Diante disso, objetivou-se avaliar o potencial biológico da Tabebuia aurea, determinando a atividade antimicrobiana; por meio do método da microdiluição em caldo, para a determinação da Concentração Inibitória Mínima (CIM; antiedematogênica, pelo ensaio de edema de orelha induzido por capsaicina; e antirradicalar, frente ao radical DPPH. Os extratos etanólicos de T. aurea não evidenciaram citotoxicidade, exceto o extrato etanólico da flor nas concentrações > 0,5 mg mL-1. O extrato etanólico da flor foi ativo com ação bactericida frente a S. epidermidis (CIM de 0,06 mg mL-1 enquanto o extrato etanólico da folha foi moderadamente ativo frente a S. epidermidis (CIM: 0,25 mg mL-1 e S. aureus (CIM: 0,50 mg mL-1 sugerindo ação bacteriostática para ambas as linhagens. Os dois extratos apresentaram ação antiedematogênica, com inibição do edema de 40,50% pelo extrato etanólico da flor e de 41,73% pelo extrato da folha. T. aurea não apresentou atividade antirradicalar. Os resultados comprovam o perfil antibacteriano e antiedematogênico com ausência de citotoxidade pela T. aurea. Sugere-se a continuação dos testes com frações e substâncias isoladas das flores e folhas da referida espécie vegetal, bem como de experimentos in vivo, como forma de agregar evidências visando à busca de novos fitoterápicos.

  4. Manifest Variable Granger Causality Models for Developmental Research: A Taxonomy

    Science.gov (United States)

    von Eye, Alexander; Wiedermann, Wolfgang

    2015-01-01

    Granger models are popular when it comes to testing hypotheses that relate series of measures causally to each other. In this article, we propose a taxonomy of Granger causality models. The taxonomy results from crossing the four variables Order of Lag, Type of (Contemporaneous) Effect, Direction of Effect, and Segment of Dependent Series…

  5. Child Care Subsidy Use and Child Development: Potential Causal Mechanisms

    Science.gov (United States)

    Hawkinson, Laura E.

    2011-01-01

    Research using an experimental design is needed to provide firm causal evidence on the impacts of child care subsidy use on child development, and on underlying causal mechanisms since subsidies can affect child development only indirectly via changes they cause in children's early experiences. However, before costly experimental research is…

  6. Causal Propagators for the Second Order Wilson Loop

    OpenAIRE

    Pimentel, B. M.; Tomazelli, J. L.

    1996-01-01

    We evaluate the Wilson loop at second order in general non-covariant gauges by means of the causal principal-value prescription for the gauge- dependent poles in the gauge-boson propagator and show that the result agrees with the usual causal prescriptions.

  7. Evidence for Deductive Reasoning in Blocking of Causal Judgments

    Science.gov (United States)

    Mitchell, C.J.; Lovibond, P.F.; Condoleon, M.

    2005-01-01

    We have recently demonstrated that pre-training of additivity (the outcome of two causal cues is larger than one causal cue) greatly enhances blocking. This manipulation could work by removing a ceiling effect on the outcome, as proposed by Cheng (1997). Alternatively, it could remove the logical ambiguity associated with blocking under…

  8. Time Symmetric Quantum Mechanics and Causal Classical Physics

    CERN Document Server

    Bopp, Fritz W

    2016-01-01

    A two boundary quantum mechanics without time ordered causal structure is advocated as consistent theory. The apparent causal structure of usual "near future" macroscopic phenomena is attributed to a cosmological asymmetry and to rules governing the transition between microscopic to macroscopic observations. Our interest is a heuristic understanding of the resulting macroscopic physics.

  9. Cause and Event: Supporting Causal Claims through Logistic Models

    Science.gov (United States)

    O'Connell, Ann A.; Gray, DeLeon L.

    2011-01-01

    Efforts to identify and support credible causal claims have received intense interest in the research community, particularly over the past few decades. In this paper, we focus on the use of statistical procedures designed to support causal claims for a treatment or intervention when the response variable of interest is dichotomous. We identify…

  10. The causal boundary and its relations with the conformal boundary

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, J, E-mail: jherrera@agt.cie.uma.e [Departamento de Algebra, GeometrIa y TopologIa, Facultad de Ciencias, Universidad de Malaga, Campus Teatinos, 29071 Malaga (Spain)

    2010-05-01

    Our aim in this note is to present the results (obtained in [2]) which ensure that, under certain regularity conditions, the conformal boundary becomes equal to the causal boundary, not only as a point set, but in a topological and chronological level. In particular, under these conditions the conformal boundary becomes a powerful tool to compute the causal one.

  11. Causal Discourse Analyzer: Improving Automated Feedback on Academic ESL Writing

    Science.gov (United States)

    Chukharev-Hudilainen, Evgeny; Saricaoglu, Aysel

    2016-01-01

    Expressing causal relations plays a central role in academic writing. While it is important that writing instructors assess and provide feedback on learners' causal discourse, it could be a very time-consuming task. In this respect, automated writing evaluation (AWE) tools may be helpful. However, to date, there have been no AWE tools capable of…

  12. Thinking Fast and Slow about Causality: Response to Palinkas

    Science.gov (United States)

    Marsh, Jeanne C.

    2014-01-01

    Larry Palinkas advances the developing science of social work by providing an explanation of how social science research methods, both qualitative and quantitative, can improve our capacity to draw casual inferences. Understanding causal relations and making causal inferences--with the promise of being able to predict and control outcomes--is…

  13. From Blickets to Synapses: Inferring Temporal Causal Networks by Observation

    Science.gov (United States)

    Fernando, Chrisantha

    2013-01-01

    How do human infants learn the causal dependencies between events? Evidence suggests that this remarkable feat can be achieved by observation of only a handful of examples. Many computational models have been produced to explain how infants perform causal inference without explicit teaching about statistics or the scientific method. Here, we…

  14. Temporal and Causal Reasoning in Deaf and Hearing Novice Readers

    Science.gov (United States)

    Sullivan, Susan; Oakhill, Jane; Arfé, Barbara; Boureux, Magali

    2014-01-01

    Temporal and causal information in text are crucial in helping the reader form a coherent representation of a narrative. Deaf novice readers are generally poor at processing linguistic markers of causal/temporal information (i.e., connectives), but what is unclear is whether this is indicative of a more general deficit in reasoning about…

  15. Quantum objects as elementary units of causality and locality

    CERN Document Server

    Diel, Hans H

    2016-01-01

    The author's attempt to construct a local causal model of quantum theory (QT) that includes quantum field theory (QFT) resulted in the identification of "quantum objects" as the elementary units of causality and locality. Quantum objects are collections of particles (including single particles) whose collective dynamics and measurement results can only be described by the laws of QT and QFT. Local causal models of quantum objects' internal dynamics are not possible if a locality is understood as a space-point locality. Within quantum objects, state transitions may occur which instantly affect the whole quantum object. The identification of quantum objects as the elementary units of causality and locality has two primary implications for a causal model of quantum objects: (1) quantum objects run autonomously with system-state update frequencies based on their local proper times and with either no or minimal dependency on external parameters. (2) The laws of physics that describe global (but relativistic) inter...

  16. A causal net approach to relativistic quantum mechanics

    Science.gov (United States)

    Bateson, R. D.

    2012-05-01

    In this paper we discuss a causal network approach to describing relativistic quantum mechanics. Each vertex on the causal net represents a possible point event or particle observation. By constructing the simplest causal net based on Reichenbach-like conjunctive forks in proper time we can exactly derive the 1+1 dimension Dirac equation for a relativistic fermion and correctly model quantum mechanical statistics. Symmetries of the net provide various quantum mechanical effects such as quantum uncertainty and wavefunction, phase, spin, negative energy states and the effect of a potential. The causal net can be embedded in 3+1 dimensions and is consistent with the conventional Dirac equation. In the low velocity limit the causal net approximates to the Schrodinger equation and Pauli equation for an electromagnetic field. Extending to different momentum states the net is compatible with the Feynman path integral approach to quantum mechanics that allows calculation of well known quantum phenomena such as diffraction.

  17. A causal net approach to relativistic quantum mechanics

    International Nuclear Information System (INIS)

    In this paper we discuss a causal network approach to describing relativistic quantum mechanics. Each vertex on the causal net represents a possible point event or particle observation. By constructing the simplest causal net based on Reichenbach-like conjunctive forks in proper time we can exactly derive the 1+1 dimension Dirac equation for a relativistic fermion and correctly model quantum mechanical statistics. Symmetries of the net provide various quantum mechanical effects such as quantum uncertainty and wavefunction, phase, spin, negative energy states and the effect of a potential. The causal net can be embedded in 3+1 dimensions and is consistent with the conventional Dirac equation. In the low velocity limit the causal net approximates to the Schrodinger equation and Pauli equation for an electromagnetic field. Extending to different momentum states the net is compatible with the Feynman path integral approach to quantum mechanics that allows calculation of well known quantum phenomena such as diffraction.

  18. Killer yeasts inhibit the growth of the phytopathogen Moniliophthora perniciosa, the causal agent of Witches' Broom disease Leveduras micocinogênicas inibem o crescimento do fitopatógeno Moniliophthora perniciosa, o agente causador da doença Vassoura-de-bruxa

    Directory of Open Access Journals (Sweden)

    Anderson de Souza Cabral

    2009-03-01

    Full Text Available Fruit and soil yeasts isolated from the Amazon, Atlantic Rainforests and an organic farm were screened for killer activity against yeasts. Killer yeasts were then tested against the phytopathogen Moniliophthora perniciosa (syn. Crinipellis perniciosa and a Dipodascus capitatus strain and a Candida sp strain inhibited its growth.Leveduras de frutas e de solo isoladas da Floresta Amazônica, Mata Atlântica e de uma fazenda orgânica foram selecionadas em uma triagem para atividade micocinogênica. As estirpes micocinogênicas foram posteriormente testadas frente a Moniliophthora perniciosa (syn. Crinipellis perniciosa. Uma estirpe de Dipodascus capitatus e outra de Candida sp.inibiram o crescimento deste fitopatógeno.

  19. Causal beliefs about depression in different cultural groups – What do cognitive psychological theories of causal learning and reasoning predict?

    Directory of Open Access Journals (Sweden)

    York eHagmayer

    2014-11-01

    Full Text Available Cognitive psychological research focusses on causal learning and reasoning while cognitive anthropological and social science research tend to focus on systems of beliefs. Our aim was to explore how these two types of research can inform each other. Cognitive psychological theories (causal model theory and causal Bayes nets were used to derive predictions for systems of causal beliefs. These predictions were then applied to lay theories of depression as a specific test case. A systematic literature review on causal beliefs about depression was conducted, including original, quantitative research. Thirty-six studies investigating 13 non-Western and 32 Western cultural groups were analysed by classifying assumed causes and preferred forms of treatment into common categories. Relations between beliefs and treatment preferences were assessed. Substantial agreement between cultural groups was found with respect to the impact of observable causes. Stress was generally rated as most important. Less agreement resulted for hidden, especially supernatural causes. Causal beliefs were clearly related to treatment preferences in Western groups, while evidence was mostly lacking for non-Western groups. Overall predictions were supported, but there were considerable methodological limitations. Pointers to future research, which may combine studies on causal beliefs with experimental paradigms on causal reasoning, are given.

  20. Simulation of system models containing zero-order causal paths - I. Classification of zero-order causal paths

    NARCIS (Netherlands)

    Dijk, van J.; Breedveld, P.C.

    1991-01-01

    The existence of zero-order causal paths in bond graphs of physical systems implies the set of state equations to be an implicit mixed set of Differential and Algebraic Equations (DAEs). In the block diagram expansion of such a bond graph, this type of causal path corresponds with a zero-order loop.

  1. Causation or only correlation? Application of causal inference graphs for evaluating causality in nano-QSAR models

    Science.gov (United States)

    Sizochenko, Natalia; Gajewicz, Agnieszka; Leszczynski, Jerzy; Puzyn, Tomasz

    2016-03-01

    In this paper, we suggest that causal inference methods could be efficiently used in Quantitative Structure-Activity Relationships (QSAR) modeling as additional validation criteria within quality evaluation of the model. Verification of the relationships between descriptors and toxicity or other activity in the QSAR model has a vital role in understanding the mechanisms of action. The well-known phrase ``correlation does not imply causation'' reflects insight statistically correlated with the endpoint descriptor may not cause the emergence of this endpoint. Hence, paradigmatic shifts must be undertaken when moving from traditional statistical correlation analysis to causal analysis of multivariate data. Methods of causal discovery have been applied for broader physical insight into mechanisms of action and interpretation of the developed nano-QSAR models. Previously developed nano-QSAR models for toxicity of 17 nano-sized metal oxides towards E. coli bacteria have been validated by means of the causality criteria. Using the descriptors confirmed by the causal technique, we have developed new models consistent with the straightforward causal-reasoning account. It was proven that causal inference methods are able to provide a more robust mechanistic interpretation of the developed nano-QSAR models.In this paper, we suggest that causal inference methods could be efficiently used in Quantitative Structure-Activity Relationships (QSAR) modeling as additional validation criteria within quality evaluation of the model. Verification of the relationships between descriptors and toxicity or other activity in the QSAR model has a vital role in understanding the mechanisms of action. The well-known phrase ``correlation does not imply causation'' reflects insight statistically correlated with the endpoint descriptor may not cause the emergence of this endpoint. Hence, paradigmatic shifts must be undertaken when moving from traditional statistical correlation analysis to causal

  2. Variações florística e estrutural e relações fitogeográficas de um fragmento de floresta decídua no Rio Grande do Norte, Brasil Floristic and structural variations, and the phytogeographical relationships of a deciduous forest fragment in Rio Grande do Norte State, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Cestaro

    2004-06-01

    Full Text Available O trabalho foi realizado num fragmento de floresta decídua com cerca de 270ha centrado em 5°53'S e 35°23'W e que se estende por dois ambientes edáficos distintos (Moda 1 e Moda 2. Os objetivos do trabalho foram caracterizar florística e estruturalmente o componente arbóreo nos dois ambientes, compará-los entre si e avaliar suas relações fitogeográficas. Todos os indivíduos vivos e mortos em pé com perímetro à altura do peito >10cm foram considerados como árvore e amostrados pelo método dos quadrantes. Para Moda 1 e Moda 2 foram estimados, respectivamente: densidade total de 1.587 e de 1.924 indivíduos.ha-1, área basal total de 15,88 e de 15,86m².ha-¹, freqüências modais das alturas entre 5 e 5,9m e entre 6 e 6,9m e dos diâmetros de caule entre 5,0 e 9,9cm e entre 3,2 e 4,9cm, índice de diversidade de Shannon de 3,19 e de 3,26 e índice de eqüabilidade de Pielou de 0,79 e de 0,86. Os estratos arbóreos nos dois ambientes foram considerados estruturalmente semelhantes. Foram observadas no total 66 espécies de árvores, sendo 56 em Moda 1 e 45 em Moda 2. Piptadenia moniliformis Benth. é a espécie com maior valor de importância nas duas áreas, seguidas por Tabebuia impetiginosa (Mart. ex DC. Standl. em Moda 1 e por Chamaecrista ensiformis (Vell. H.S. Irwin & Barneby em Moda 2. As áreas apresentam grande similaridade florística (S S = 0,69 e S C = 0,53, sendo que as espécies características de matas decíduas são mais abundantes em ou exclusivas de Moda 1, e as espécies características das Caatingas, em Moda 2. As pequenas diferenças florística e estrutural entre os dois setores da mata podem ser atribuídas às condições edáficas. Em termos florísticos, fisionômicos e ambientais, a mata foi classificada como um tipo de vegetação de transição entre as províncias fitogeográficas Atlântica e das Caatingas, com a presença destacada de espécies com ampla distribuição nas matas secas neotropicais e

  3. Generalized Causal Set d'Alembertians

    CERN Document Server

    Aslanbeigi, Siavash; Sorkin, Rafael D

    2014-01-01

    We introduce a family of generalized d'Alembertian operators in D-dimensional Minkowski spacetimes which are manifestly Lorentz-invariant, retarded, and non-local, the extent of the nonlocality being governed by a single parameter $\\rho$. The prototypes of these operators arose in earlier work as averages of matrix operators meant to describe the propagation of a scalar field in a causal set. We generalize the original definitions to produce an infinite family of ''Generalized Causet Box (GCB) operators'' parametrized by certain coefficients $\\{a,b_n\\}$, and we derive the conditions on the latter needed for the usual d'Alembertian to be recovered in the infrared limit. The continuum average of a GCB operator is an integral operator, and it is these continuum operators that we mainly study. To that end, we compute their action on plane waves, or equivalently their Fourier transforms g(p) [p being the momentum-vector]. For timelike p, g(p) has an imaginary part whose sign depends on whether p is past or future-...

  4. Causal mediation analysis with a latent mediator.

    Science.gov (United States)

    Albert, Jeffrey M; Geng, Cuiyu; Nelson, Suchitra

    2016-05-01

    Health researchers are often interested in assessing the direct effect of a treatment or exposure on an outcome variable, as well as its indirect (or mediation) effect through an intermediate variable (or mediator). For an outcome following a nonlinear model, the mediation formula may be used to estimate causally interpretable mediation effects. This method, like others, assumes that the mediator is observed. However, as is common in structural equations modeling, we may wish to consider a latent (unobserved) mediator. We follow a potential outcomes framework and assume a generalized structural equations model (GSEM). We provide maximum-likelihood estimation of GSEM parameters using an approximate Monte Carlo EM algorithm, coupled with a mediation formula approach to estimate natural direct and indirect effects. The method relies on an untestable sequential ignorability assumption; we assess robustness to this assumption by adapting a recently proposed method for sensitivity analysis. Simulation studies show good properties of the proposed estimators in plausible scenarios. Our method is applied to a study of the effect of mother education on occurrence of adolescent dental caries, in which we examine possible mediation through latent oral health behavior. PMID:26363769

  5. Reconstructing Causal Biological Networks through Active Learning.

    Science.gov (United States)

    Cho, Hyunghoon; Berger, Bonnie; Peng, Jian

    2016-01-01

    Reverse-engineering of biological networks is a central problem in systems biology. The use of intervention data, such as gene knockouts or knockdowns, is typically used for teasing apart causal relationships among genes. Under time or resource constraints, one needs to carefully choose which intervention experiments to carry out. Previous approaches for selecting most informative interventions have largely been focused on discrete Bayesian networks. However, continuous Bayesian networks are of great practical interest, especially in the study of complex biological systems and their quantitative properties. In this work, we present an efficient, information-theoretic active learning algorithm for Gaussian Bayesian networks (GBNs), which serve as important models for gene regulatory networks. In addition to providing linear-algebraic insights unique to GBNs, leading to significant runtime improvements, we demonstrate the effectiveness of our method on data simulated with GBNs and the DREAM4 network inference challenge data sets. Our method generally leads to faster recovery of underlying network structure and faster convergence to final distribution of confidence scores over candidate graph structures using the full data, in comparison to random selection of intervention experiments. PMID:26930205

  6. Reconstructing Causal Biological Networks through Active Learning.

    Directory of Open Access Journals (Sweden)

    Hyunghoon Cho

    Full Text Available Reverse-engineering of biological networks is a central problem in systems biology. The use of intervention data, such as gene knockouts or knockdowns, is typically used for teasing apart causal relationships among genes. Under time or resource constraints, one needs to carefully choose which intervention experiments to carry out. Previous approaches for selecting most informative interventions have largely been focused on discrete Bayesian networks. However, continuous Bayesian networks are of great practical interest, especially in the study of complex biological systems and their quantitative properties. In this work, we present an efficient, information-theoretic active learning algorithm for Gaussian Bayesian networks (GBNs, which serve as important models for gene regulatory networks. In addition to providing linear-algebraic insights unique to GBNs, leading to significant runtime improvements, we demonstrate the effectiveness of our method on data simulated with GBNs and the DREAM4 network inference challenge data sets. Our method generally leads to faster recovery of underlying network structure and faster convergence to final distribution of confidence scores over candidate graph structures using the full data, in comparison to random selection of intervention experiments.

  7. Dynamic causal models and autopoietic systems.

    Science.gov (United States)

    David, Olivier

    2007-01-01

    Dynamic Causal Modelling (DCM) and the theory of autopoietic systems are two important conceptual frameworks. In this review, we suggest that they can be combined to answer important questions about self-organising systems like the brain. DCM has been developed recently by the neuroimaging community to explain, using biophysical models, the non-invasive brain imaging data are caused by neural processes. It allows one to ask mechanistic questions about the implementation of cerebral processes. In DCM the parameters of biophysical models are estimated from measured data and the evidence for each model is evaluated. This enables one to test different functional hypotheses (i.e., models) for a given data set. Autopoiesis and related formal theories of biological systems as autonomous machines represent a body of concepts with many successful applications. However, autopoiesis has remained largely theoretical and has not penetrated the empiricism of cognitive neuroscience. In this review, we try to show the connections that exist between DCM and autopoiesis. In particular, we propose a simple modification to standard formulations of DCM that includes autonomous processes. The idea is to exploit the machinery of the system identification of DCMs in neuroimaging to test the face validity of the autopoietic theory applied to neural subsystems. We illustrate the theoretical concepts and their implications for interpreting electroencephalographic signals acquired during amygdala stimulation in an epileptic patient. The results suggest that DCM represents a relevant biophysical approach to brain functional organisation, with a potential that is yet to be fully evaluated. PMID:18575681

  8. Causality and supersymmetry in the superstring theory

    International Nuclear Information System (INIS)

    Reduction of the ten-dimensional, heterotic-superstring effective action S-circumflex including quartic higher-derivative terms R-circumflex4 yields a physical four-action S which is tachyon-free up to quadratic order R2 - the masses M0 and M2 of the spin-0 and spin-2 particles are both real - when the internal six-space is a Calabi-Yau metric g-barμν and N=1 supersymmetry is preserved via equation dH-bar≡tr(R-bar and R-bar)-Tr(F-bar and F-bar)/30=0, where H-barμνξ is the totally antisymmetric three-index field (while the bosonic string and type-II superstring may contain a spin-2 tachyon and a spin-0 tachyon, respectively). Here, we show that this crucial feature is independent of imposing supersymmetry, for if dH-bar≠ 0, there is an additional contribution to R2 which, however, produces no tachyons. Thus, the requirement of a stable, causal theory singles out the heterotic superstring irrespective of the requirement of N=1 supersymmetry, which is essential at high energies rather for its roles in the vanishing of the cosmological constant and the maintenance of the gauge hierarchy

  9. Body selectivity in occipitotemporal cortex: Causal evidence.

    Science.gov (United States)

    Downing, Paul E; Peelen, Marius V

    2016-03-01

    Perception of others' bodies provides information that is useful for a number of important social-cognitive processes. Evidence from neuroimaging methods has identified focal cortical regions that are highly selective for perceiving bodies and body parts, including the extrastriate body area (EBA) and fusiform body area (FBA). Our understanding of the functional properties of these regions, and their causal contributions to behavior, has benefitted from the study of neuropsychological patients and particularly from investigations using transcranial magnetic stimulation (TMS). We review this evidence, focusing on TMS studies that are revealing of how (and when) activity in EBA contributes to detecting people in natural scenes; to resolving their body shape, movements, actions, individual parts, and identities; and to guiding goal-directed behavior. These findings are considered in reference to a framework for body perception in which the patterns of neural activity in EBA and FBA jointly serve to make explicit the elements of the visual scene that correspond to the body and its parts. These representations are modulated by other sources of information such as prior knowledge, and are shared with wider brain networks involved in many aspects of social cognition. PMID:26044771

  10. La organización de eventos como estrategia identitaria y evocadora de imagen turística. Estudio de caso: Girona Temps de Flors

    Directory of Open Access Journals (Sweden)

    Mònika Jiménez Morales

    2009-01-01

    Full Text Available Desde hace 53 años la ciudad de Girona organiza un evento multitudinario basado en el arte floral que, en sus últimas ediciones, ha llegado a movilizar a más de medio millón de visitantes, muchos de ellos llegados de todas partes de Europa. Más allá de las flores, las exposiciones fotográficas o los montajes audiovisuales que llenan las calles del casco antiguo del municipio durante la segunda semana del mes de mayo, lo cierto es que Girona Temps de Flors representa la puesta en escena de una estrategia comunicativa emergente en el ámbito de la promoción del territorio. En efecto, el evento desempeña, per se, variadas funciones en el ámbito emocional del espacio vivido, pero hay más. También puede devenir a modo de catalizador de imágenes, de creador de imaginarios capaces de fijar una marca de ciudad en su conjunto. El presente artículo dará a conocer las posibilidades que se desprenden de la organización de un evento en relación al posicionamiento identitario y de marca de un territorio.

  11. Caracterización de las antocianinas de la flor de ceibo como sensibilizadores naturales para su uso en celdas fotovoltaicas

    Directory of Open Access Journals (Sweden)

    María Paula Enciso

    2014-12-01

    Full Text Available La energía solar es la fuente de energía más promisoria del futuro, ya que la conversión directa de luz solar en energía eléctrica mediante el uso de celdas solares posee muchas ventajas sobre los métodos usados en la actualidad, debido a que no genera desechos o contaminantes.En particular, las celdas solares sensibilizadas con pigmentos (DSSC o celdas de Graetzel representan una alternativa a las convencionales celdas solares de silicio. En las últimas tres décadas han atraído considerable atención como una forma de producir celdas fotovoltaicas de bajo costo debido a la posibilidad de alcanzar una alta eficiencia de conversión (de aprox. 12% y su alto rendimiento durante períodos de luz prolongados e incluso en condiciones de stress térmico.En este trabajo se evalúan pigmentos de origen natural, la mezcla de antocianinas provenientes de la flor del ceibo, como sensibilizadores de estas celdas. Se utilizan medidas de absorbancia UV-visible, voltamperometría cíclica y espectroscopía de impedancia electroquímica como forma de caracterización.

  12. Time reordered: Causal perception guides the interpretation of temporal order.

    Science.gov (United States)

    Bechlivanidis, Christos; Lagnado, David A

    2016-01-01

    We present a novel temporal illusion in which the perceived order of events is dictated by their perceived causal relationship. Participants view a simple Michotte-style launching sequence featuring 3 objects, in which one object starts moving before its presumed cause. Not only did participants re-order the events in a causally consistent way, thus violating the objective temporal order, but they also failed to recognise the clip they had seen, preferring a clip in which temporal and causal order matched. We show that the effect is not due to lack of attention to the presented events and we discuss the problem of determining whether causality affects temporal order at an early perceptual stage or whether it distorts an accurately perceived order during retrieval. Alternatively, we propose a mechanism by which temporal order is neither misperceived nor misremembered but inferred "on-demand" given phenomenal causality and the temporal priority principle, the assumption that causes precede their effects. Finally, we discuss how, contrary to theories of causal perception, impressions of causality can be generated from dynamic sequences with strong spatiotemporal deviations. PMID:26402648

  13. Causality between Prices and Wages: VECM Analysis for EU-27

    Directory of Open Access Journals (Sweden)

    Adriatik Hoxha

    2010-09-01

    Full Text Available The literature on causality as well as the empirical evidence clearly shows that there are two opposing groups of economists, who support different hypotheses with respect to the flow of causality in the price-wage causal relationship. The first group argues that causality runs from wages to prices, whereas the second argues that effect flows from prices to wages. Nonetheless, the literature review suggeststhat there is at least some consensus in that researcher’s conclusions may be contingent on the type of data employed, applied econometric model, or even that relationship may alter with economic cycles. This paper empirically examines theprice-wage causal relationship in EU-27, by using the OLS and VECM analysis, and it also provides robust evidence in support of a bilateral causal relationship between prices and wages, both in long-run as well as in the shortrun.Prior to designing and estimating the econometric model we have performed stationarity tests for the employed price, wage and productivity variables. Additionally, we have also specified the model taking into account the lag order as well as the rank of co-integration for the co-integrated variables. Furthermore, we have also applied respective restrictions on the parameters of estimatedVECM. The evidence resulting from model robustness checks indicates that results are statistically robust. Although far from closing the issue of causality between prices and wages, this paper at least provides some fresh evidence in the case of EU-27.

  14. Causality between Prices and Wages: VECM Analysis for EU-12

    Directory of Open Access Journals (Sweden)

    Adriatik HOXHA

    2010-05-01

    Full Text Available The literature on causality as well as the empirical evidence clearly shows that there are two opposing groups of economists, who support different hypotheses with respect to the flow of causality in the price-wage causal relationship. The first group argues that causality runs from wages to price, whereas the second argue that effect flows from prices to wages. Nonetheless, there is at least some consensus that researchers conclusions may be contingent on the type of data employed, applied econometric model, or even that the relationship may vary through economic cycles. This paper empirically examines the pricewage causal relationship in EMU, by using OLS and VECM analysis, and also it provides robust evidence in support of a bilateral causal relationship between prices and wages, both in long-run as well as in the short-run. Prior to designing and estimating the econometric model we have performed stationarity tests for the employed price, wage and productivity variables. Additionally, we have also specified the model taking into account the lag order as well as the rank of co-integration for the co-integrated variables. Furthermore, we have also applied respective restrictions on the parameters of the estimated VECM and finally model robustness checks indicate that results are statistically robust. Although far from closing the issue of causality between prices and variables, this paper at least provides some fresh evidence for the case of EMU.

  15. Conservação da biodiversidade em pastagens: espécies vegetais em risco

    OpenAIRE

    Espírito-Santo, M. D.; Aguiar, Carlos

    2008-01-01

    As plantas herbáceas pratenses surgiram, pela primeira vez, em períodos muito recuados da história evolutiva das plantas com flor. Existem evidências de que no final do Mesozóico existiam já plantas adaptadas à pressão de pastoreio, neste caso por dinossáurios herbívoros. Supõe-se que estabilidade do clima tropical característico do Paleogénico não favoreceu a diversificação das plantas herbáceas. O recuo dos bosques tropicais terciários, causado pela diferenciação dos climas mediterrânico e ...

  16. A Complex Systems Approach to Causal Discovery in Psychiatry.

    Directory of Open Access Journals (Sweden)

    Glenn N Saxe

    Full Text Available Conventional research methodologies and data analytic approaches in psychiatric research are unable to reliably infer causal relations without experimental designs, or to make inferences about the functional properties of the complex systems in which psychiatric disorders are embedded. This article describes a series of studies to validate a novel hybrid computational approach--the Complex Systems-Causal Network (CS-CN method-designed to integrate causal discovery within a complex systems framework for psychiatric research. The CS-CN method was first applied to an existing dataset on psychopathology in 163 children hospitalized with injuries (validation study. Next, it was applied to a much larger dataset of traumatized children (replication study. Finally, the CS-CN method was applied in a controlled experiment using a 'gold standard' dataset for causal discovery and compared with other methods for accurately detecting causal variables (resimulation controlled experiment. The CS-CN method successfully detected a causal network of 111 variables and 167 bivariate relations in the initial validation study. This causal network had well-defined adaptive properties and a set of variables was found that disproportionally contributed to these properties. Modeling the removal of these variables resulted in significant loss of adaptive properties. The CS-CN method was successfully applied in the replication study and performed better than traditional statistical methods, and similarly to state-of-the-art causal discovery algorithms in the causal detection experiment. The CS-CN method was validated, replicated, and yielded both novel and previously validated findings related to risk factors and potential treatments of psychiatric disorders. The novel approach yields both fine-grain (micro and high-level (macro insights and thus represents a promising approach for complex systems-oriented research in psychiatry.

  17. Produtividade e podridão parda em couve-flor 'Sharon' influenciadas pela aplicação de nitrogênio e boro Yield and incidence of hollow stem disorder of cauliflower 'Sharon' influenced by the application of nitrogen and boron

    Directory of Open Access Journals (Sweden)

    Mônica S de Camargo

    2009-03-01

    Full Text Available A podridão parda é um problema comum em couve-flor que ocasiona sintoma semelhante ao da deficiência de B. Sua ocorrência está associada, especialmente, às adubações com nitrogênio e boro, mas há escassez de informações sobre o problema no Brasil. Neste trabalho avaliou-se o efeito de doses de nitrogênio e épocas de aplicação de boro na produção e na incidência de podridão parda da couve-flor 'Sharon'. O experimento foi realizado em Argissolo Vermelho Amarelo de novembro/2005 a fevereiro/2006, com quatro doses de N (100; 150; 200 e 250 kg ha-1 e duas épocas de aplicação de 3 kg ha-1 B (1 e 2 aplicações, além do controle (sem aplicação. O diâmetro das cabeças e a produtividade comercial variaram de 16,45 a 22,03 cm e 15,71 a 29 t ha-1, respectivamente, e não foram influenciados pelos tratamentos. As doses de N proporcionaram aumento linear no teor nas folhas e nas cabeças. O caule oco e bronzeamento das cabeças foram reduzidos, enquanto a produtividade comercial aumentou com aplicação de B. Houve correlação negativa entre o teor de B nas folhas (r=0,66; pThe hollow stem disorder is a common problem in cauliflower, resulting in similar symptoms as those caused by B deficiency. Its occurrence in cauliflower is related to nitrogen and boron levels. There exist little information about this subject in Brazil. The effect of nitrogen rates and boron application periods were evaluated on the cauliflower production and incidence of hollow stem. The experiment was carried out from November 2005 through February 2006 in a Kandiustalf soil (0.54 mg B kg-1, BaCl2 1.25 mg L-1 at Tietê region, São Paulo State, Brazil, in a randomized complete block design with four replicates, four N levels (100; 150; 200 and 250 kg ha-1 and two periods of B application (one and two applications and a control (without application. Cauliflower curd diameter ranged from 16.45 to 22.03 cm and the commercial yield from 15.71 to 29 t ha-1

  18. Causality and prediction: differences and points of contact

    Directory of Open Access Journals (Sweden)

    Luis Carlos Silva Ayçaguer, PhD

    2014-09-01

    Full Text Available This contribution presents the differences between those variables that might play a causal role in a certain process and those only valuable for predicting the outcome. Some considerations are made about the core intervention of the association and the temporal precedence and biases in both cases, the study of causality and predictive modeling. In that context, several relevant aspects related to the design of the corresponding studies are briefly reviewed and some of the mistakes that are often committed in handling both, causality and prediction, are illustrated.

  19. Stock Market and Economic Growth in Malaysia: Causality Test

    OpenAIRE

    Har Wai Mun; Ee Chun Siong; Tan Chai Thing

    2009-01-01

    Stock market has been associated with economic growth through its role as source for new private capital.  On the other hand, economic growth may be the catalyst for stock market growth. Thus, the purpose of this paper was to explore causal relationships between stock market and the economy using formal tests of causality developed by C. J. Granger and yearly Malaysia data for the period 1977-2006. Results show that stock market Granger-caused economic activity with no reverse causality obser...

  20. Spatial Causality. An application to the Deforestation Process in Bolivia

    Directory of Open Access Journals (Sweden)

    Javier Aliaga

    2011-01-01

    Full Text Available This paper analyses the causes of deforestation for a representative set of Bolivian municipalities. The literature on environmental economics insists on the importance of physical and social factors. We focus on the last group of variables. Our objective is to identify causal mechanisms between these factors of risk and the problem of deforestation. To this end, we present a testing strategy for spatial causality, based on a sequence of Lagrange Multipliers. The results that we obtain for the Bolivian case confirm only partially the traditional view of the problem of deforestation. Indeed, we only find unequivocal signs of causality in relation to the structure of property rights.

  1. Effects of inhomogeneity on the causal entropic prediction of Λ

    Science.gov (United States)

    Phillips, Daniel; Albrecht, Andreas

    2011-12-01

    The causal entropic principle aims to predict the unexpectedly small value of the cosmological constant Λ using a weighting by entropy increase on causal diamonds. The original work assumed a purely isotropic and homogeneous cosmology. But even the level of inhomogeneity observed in our universe forces reconsideration of certain arguments about entropy production. In particular, we must consider an ensemble of causal diamonds associated with each background cosmology and we can no longer immediately discard entropy production in the far future of the universe. Depending on our choices for a probability measure and our treatment of black hole evaporation, the prediction for Λ may be left intact or dramatically altered.

  2. Floristic composition and growth of weeds under custard apple (Annona squamosa progenies Composição florística e crescimento de plantas daninhas sob a copa de progênies de fruta-do-conde (Annona squamosa

    Directory of Open Access Journals (Sweden)

    P.S.L. Silva

    2004-12-01

    ção ambiental. Dentre esses métodos, a adoção de cultivares com maior habilidade competitiva com as PD tem despertado atenção internacional. O objetivo do trabalho foi avaliar a composição florística e o crescimento de PD sob a copa de progênies de pinheira irrigadas. Vinte progênies de meias-irmãs, com idade aproximada de três anos, foram avaliadas no delineamento de blocos ao acaso, com cinco repetições e quatro plantas por parcela. Ao redor do caule de cada planta estabeleceu-se um círculo com área de 0,5 m². Nessa área, foram avaliadas a composição e as massas das matérias fresca e seca da parte aérea das PD. Avaliaram-se também os diâmetros do colo e da copa e a área da folha das progênies. Ocorreram 58 espécies de PD. As famílias com maior número de espécies, em ordem decrescente, foram Leguminosae, Convolvulaceae, Euphorbiaceae, Malvaceae e Sterculiaceae. O número de espécies de PD/parcela variou de 6 a 18, porém não houve diferença entre a porcentagem média de diferentes PD sob a copa das progênies. As menores massas de matérias fresca e seca de PD ocorreram nas progênies JG1 e SM8, respectivamente. Não houve diferenças entre progênies quanto a diâmetro do colo e área foliar, mas sob a copa da progênie FE4, que apresentou o maior diâmetro da copa, observou-se um dos menores rendimentos de matéria seca de PD.

  3. Levantamento florístico de um trecho de floresta serrana no planalto de Garanhuns, Estado de Pernambuco - DOI: 10.4025/actascibiolsci.v25i1.2120 Flora survey of a mountain forest stretch in Garanhuns, state of Pernambuco - DOI: 10.4025/actascibiolsci.v25i1.2120

    Directory of Open Access Journals (Sweden)

    Maria Jesus Nogueira Rodal

    2003-04-01

    Full Text Available Este trabalho visa contribuir para o conhecimento da flora dos brejos de altitude do Estado de Pernambuco, Brasil. Foi realizado o levantamento florístico de um remanescente de floresta estacional semidecidual Montana, localizado na Fazenda Monteiro (8º53’25”S’ e 36º 29’34”W’, Garanhuns, Pernambuco. As coletas de material botânico tiveram início no mês de julho de 1998, representando os diferentes hábitos. O material coletado foi processado segundo os métodos usuais em taxonomia. Foram registradas 69 espécies, acomodadas em 58 gêneros e 31 famílias, com destaque pelo maior número de espécies para: Euphorbiaceae (06, Asteraceae e Caesalpiniaceae (05, Fabaceae, Rubiaceae, Sapindaceae e Solanaceae (04. Dentre as espécies ocorrentes na área em estudo, verificaram-se: Senna rizzinii Irwin & Barneby, Casearia sylvestris Swartz., Bowdichia virgilioides Kunth e Enterolobium contortisiliquum (Vell. MorongThe aim of this paper is to contribute for the flora information of marsh forests in the state of Pernambuco, Brazil. A flora survey of a semi-deciduous mountain stationary forest located in Garanhuns plateau, in Monteiro farm (latitude 8º53’25”S and longitude 36º29’34”, in Garanhuns, Pernambuco was carried out. The botanical material collection started in July 1998, representing different habits. The collected material was processed according to methods adopted in plant taxonomy. 69 species were recorded, allocated in 58 genre and 31 families, standing out by the greatest number of species to: Euphorbiaceae (06, Asteraceae and Caesalpiniaceae (05, Fabaceae, Rubiaceae, Sapindaceae and Solanaceae (04 each. Amongest the species studied, Senna rizzinii Irwin & Barneby, Casearia sylvestris Swartz, Bowdichia virgilioides Kunth and Enterolobium contortisiliquum (Vell. Morong were verified

  4. Éter, espírito animal e causalidade no Siris de George Berkeley: uma visão imaterialista da analogia entre macrocosmo e microcosmo Ether, animal spirit and causality in George Berkeley’s Siris: an imaterialist vision of the analogy between macro and microcosmos

    Directory of Open Access Journals (Sweden)

    Silvia Alejandra Manzo

    2004-06-01

    Full Text Available A obra de Berkeley se desenvolveu como uma refutação do ceticismo e do ateísmo nos quais via uma ameaça à filosofia. No entanto, os seus interesses intelectuais não se limitaram a isso. Os temas científicos também integravam a agenda berkeleiana, nas diferentes obras onde se adverte que a metafísica penetra todos os rincões de sua especulação sobre a ciência. No Siris, uma obra peculiar dentro do corpus berkeleiano, as reflexões acerca do mundo natural são apresentadas em franca conexão com uma concepção metafísica geral. Berkeley desdobra ali uma visão da natureza próxima do neoplatonismo e do estoicismo, que culmina com um hino à filosofia antiga e neoplatônica. Nesse quadro são abordados diferentes aspectos filosóficos e científicos, entre outros, a analogia entre microcosmo e macrocosmo, que se apresenta como uma realidade indiscutível. Berkeley entende que esse vínculo entre o homem e o mundo é possível mediante o éter, uma entidade à qual confere características muito especiais. O objetivo deste trabalho é expor a maneira como Berkeley concebe essa analogia partindo da tradição filosófica e das teorias científicas de seu tempo e ligando-a à imagem moderna do mundo.Berkeley's thought was developed as a refusal of materialism and skepticism that in his opinion menaced philosophy. However, his intellectual interests were not confined to this aim. Scientific topics were also included in Berkeley's agenda. In the works concerned with scientific issues, the omnipresence of his metaphysics is to be found. In Siris, a peculiar work in the Berkelian corpus, reflexions about the natural world are exhibited in explicit link with a metaphysical frame. Berkeley exposes a view of nature akin to neoplatonism and stoicism and ends his work with an anthem in honor of ancient and neoplatonic philosophy. Several scientific topics are dealt with, such as the analogy between macrocosm and microcosm, that it is exposed as

  5. Florística e estrutura de comunidades arbóreas em cerrados de Rondônia,Brasil Flora and structure of tree communities in dry savannas in Rodônia, Brazil

    Directory of Open Access Journals (Sweden)

    Izildinha Souza Miranda

    2006-12-01

    Full Text Available O cerrado constitui o segundo maior e mais diverso bioma brasileiro, configurando um heterogêneo mosaico fisionômico e florístico. Mais de seis mil espécies de fanerógamas são reportadas para o cerrado do Brasil Central. Este trabalho teve o objetivo de descrever e analisar a flora e a estrutura de quatro comunidades de árvores dos cerrados sensu latu do município de Vilhena, Rondônia, Brasil. As áreas estudadas foram: cerradão (Área 1, campo sujo (Área 2 e duas comunidades do cerrado sensu stricto (Áreas 3 e 4. Em cada área foi posicionado aleatoriamente um transecto de 10 x 1000 m (1 ha, dividido em 100 parcelas de 10 X 10 m. Todas as plantas vivas e mortas com circunferência do tronco e" 10 cm ao nível do solo foram registradas. O cerradão apresentou a maior riqueza específica, estrutura de tamanho e área basal. As percentagens de árvores mortas foram mais altas nas áreas de cerradão e campo sujo, com ocorrência de fogo recente. As famílias mais importantes foram Vochysiaceae, Ochnaceae, Clusiaceae, Malpighiaceae e Melastomataceae. As espécies mais importantes foram Qualea multiflora, Byrsonima crassifolia (área 1, Eugenia sp., Miconia sp.1 (área 2, Ouratea hexasperma, Caraipa savannarum (área 3, Ouratea hexasperma, Pouteria sp.3 (área 4. A maioria das espécies ocorre somente em uma área, sugerindo que a priorização de áreas para conservação deve envolver todo o mosaico de cerrados existentes. A mortalidade associada ao fogo é diferenciada entre as áreas, talvez induzida pelo grau de flamabilidade, recorrência do fogo e de fatores históricos do uso da terra.The Neotropical savannas, locally called "cerrado", are Brazil's second largest and diverse biome, constituting a heterogeneous physiognomic and floristic mosaic from which more than 6,000 species have been reported to date. This study describes and analyzes the floras and structures of four tree communities from dry savannas in the municipality of

  6. Dynamic Interactions in Artificial Environments: Causal and Non-Causal Aspects for the Emergence of Meaning

    Directory of Open Access Journals (Sweden)

    Argyris Arnellos

    2005-02-01

    Full Text Available Initially, the analysis and development of adaptive artificial systems has been based in metaphors taken from philosophical schools as well as the disciplines of biology and cognitive science. So far, the dominant approaches exhibit many advantages in specific domains of application but there all have a certain drawback, which is their inability to produce an artificial system which will be able to internally ground its representations so as to use them to produce newer, more developed ones. The respective frameworks are studied in terms of this inability and it is concluded that the problem is traced in the purely causal treatment, function and creation of the notion of representation, wherever it is used. In the case of purely dynamic systems, where the representations seem not to be very useful, it is proposed that the incorporation of a special non-causal kind of representations would give a framework which seems promising in realizing real adaptation. The relevant architecture is analyzed and discussed mainly in terms of its functionality and its contribution to the integration of pragmatic meaning aspects in an artificial system's interaction.

  7. Eventos Quânticos e Reducionismo Causal

    Directory of Open Access Journals (Sweden)

    Osvaldo Pessoa Jr.

    2013-12-01

    Full Text Available This paper is the first step in an investigation of whether microscopic events can be reduced to a mereological composition of elementary events, especially in biological systems. The hypothesis is made that, between events in which quanta are exchanged, there is causal flow, but strictly speaking no events take place. A causal event is characterized by the possibility of an intervention or manipulation. Thus, three types of quantum mechanical events may be found: (1 detection of a quantum of energy; (2 confinement by an apparatus in a Glauber coherent state; (3 null result measurement (without exchange of quanta. The paper explores these three types of elementary causal events, e sets forth as the next step the investigation of the causal events involved in the action of a molecular motor.

  8. On the causal structure between CO2 and global temperature.

    Science.gov (United States)

    Stips, Adolf; Macias, Diego; Coughlan, Clare; Garcia-Gorriz, Elisa; Liang, X San

    2016-01-01

    We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aerosol direct and indirect forcing, and on short time periods, volcanic forcings. In contrast the causality contribution from natural forcings (solar irradiance and volcanic forcing) to the long term trend is not significant. The spatial explicit analysis reveals that the anthropogenic forcing fingerprint is significantly regionally varying in both hemispheres. On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes. PMID:26900086

  9. Environment - Assisted Invariance, Causality, and Probabilities in Quantum Physics

    OpenAIRE

    Zurek, W. H.

    2002-01-01

    I introduce environment - assisted invariance -- a symmetry related to causality that is exhibited by correlated quantum states -- and describe how it can be used to understand the nature of ignorance and, hence, the origin of probabilities in quantum physics.

  10. On the causal structure between CO2 and global temperature

    Science.gov (United States)

    Stips, Adolf; Macias, Diego; Coughlan, Clare; Garcia-Gorriz, Elisa; Liang, X. San

    2016-02-01

    We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aerosol direct and indirect forcing, and on short time periods, volcanic forcings. In contrast the causality contribution from natural forcings (solar irradiance and volcanic forcing) to the long term trend is not significant. The spatial explicit analysis reveals that the anthropogenic forcing fingerprint is significantly regionally varying in both hemispheres. On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes.

  11. Holographic entanglement and causal information in coherent states

    International Nuclear Information System (INIS)

    Scalar solitons in global AdS4 are holographically dual to coherent states carrying a non-trivial condensate of a scalar operator. We study the holographic information content of these states, focusing on a particular spatial region, by examining the entanglement entropy and causal holographic information. We show generically that whenever the dimension of the condensed operator is sufficiently low (characterized by the double-trace operator becoming relevant), such coherent states have lower entanglement and causal holographic information than the vacuum state of the system, despite having greater energy. We also use these geometries to illustrate the fact that causal wedges associated with a simply-connected boundary region can have non-trivial topology even in causally trivial spacetimes

  12. Causal association rule mining methods based on fuzzy state description

    Institute of Scientific and Technical Information of China (English)

    Liang Kaijian; Liang Quan; Yang Bingru

    2006-01-01

    Aiming at the research that using more new knowledge to develope knowledge system with dynamic accordance, and under the background of using Fuzzy language field and Fuzzy language values structure as description framework, the generalized cell Automation that can synthetically process fuzzy indeterminacy and random indeterminacy and generalized inductive logic causal model is brought forward. On this basis, a kind of the new method that can discover causal association rules is provded. According to the causal information of standard sample space and commonly sample space,through constructing its state (abnormality) relation matrix, causal association rules can be gained by using inductive reasoning mechanism. The estimate of this algorithm complexity is given,and its validity is proved through case.

  13. Causality assessment: A brief insight into practices in pharmaceutical industry

    Directory of Open Access Journals (Sweden)

    R Purushotham Naidu

    2013-01-01

    Full Text Available Healthcare industry is flooded with multitude of drugs, and the list is increasing day by day. Consumption of medications has enormously increased due to life style changes, having safer drugs is the need of the hour. Regulators and other authorities to have a check have put in stringent regulations and pharmacovigilance system in place. Eventhough there has been increase in adverse drug reactions (ADR reporting in the last decade, causality assessment has been the greater challenge for academicians and even industry. Causality is crucial for risk benefit assessment, particularly when it involves post marketing safety signals. Pharmaceutical companies have put in efforts to have a standardized approach for causality assessment. This article will provide some insight into the approaches for causality assessment from a pharma industry perspective.

  14. Replicating the benefits of closed timelike curves without breaking causality

    CERN Document Server

    Yuan, Xiao; Thompson, Jayne; Haw, Jing Yan; Vedral, Vlatko; Ralph, Timothy C; Lam, Ping Koy; Weedbrook, Christian; Gu, Mile

    2014-01-01

    In general relativity, closed timelike curves can break causality with remarkable and unsettling consequences. At the classical level, they induce causal paradoxes disturbing enough to motivate conjectures that explicitly prevent their existence. At the quantum level, resolving such paradoxes induce radical benefits - from cloning unknown quantum states to solving problems intractable to quantum computers. Instinctively, one expects these benefits to vanish if causality is respected. Here we show that in harnessing entanglement, we can efficiently solve NP-complete problems and clone arbitrary quantum states - even when all time-travelling systems are completely isolated from the past. Thus, the many defining benefits of closed timelike curves can still be harnessed, even when causality is preserved. Our results unveil the subtle interplay between entanglement and general relativity, and significantly improve the potential of probing the radical effects that may exist at the interface between relativity and q...

  15. Learning Why Things Change: The Difference-Based Causality Learner

    CERN Document Server

    Voortman, Mark; Druzdzel, Marek J

    2012-01-01

    In this paper, we present the Difference- Based Causality Learner (DBCL), an algorithm for learning a class of discrete-time dynamic models that represents all causation across time by means of difference equations driving change in a system. We motivate this representation with real-world mechanical systems and prove DBCL's correctness for learning structure from time series data, an endeavour that is complicated by the existence of latent derivatives that have to be detected. We also prove that, under common assumptions for causal discovery, DBCL will identify the presence or absence of feedback loops, making the model more useful for predicting the effects of manipulating variables when the system is in equilibrium. We argue analytically and show empirically the advantages of DBCL over vector autoregression (VAR) and Granger causality models as well as modified forms of Bayesian and constraintbased structure discovery algorithms. Finally, we show that our algorithm can discover causal directions of alpha r...

  16. Causality and complexity: the myth of objectivity in science.

    Science.gov (United States)

    Mikulecky, Donald C

    2007-10-01

    Two distinctly different worldviews dominate today's thinking in science and in the world of ideas outside of science. Using the approach advocated by Robert M. Hutchins, it is possible to see a pattern of interaction between ideas in science and in other spheres such as philosophy, religion, and politics. Instead of compartmentalizing these intellectual activities, it is worthwhile to look for common threads of mutual influence. Robert Rosen has created an approach to scientific epistemology that might seem radical to some. However, it has characteristics that resemble ideas in other fields, in particular in the writings of George Lakoff, Leo Strauss, and George Soros. Historically, the atmosphere at the University of Chicago during Hutchins' presidency gave rise to Rashevsky's relational biology, which Rosen carried forward. Strauss was writing his political philosophy there at the same time. One idea is paramount in all this, and it is Lakoff who gives us the most insight into how the worldviews differ using this idea. The central difference has to do with causality, the fundamental concept that we use to build a worldview. Causal entailment has two distinct forms in Lakoff 's analysis: direct causality and complex causality. Rosen's writings on complexity create a picture of complex causality that is extremely useful in its detail, grounding in the ideas of Aristotle. Strauss asks for a return to the ancients to put philosophy back on track. Lakoff sees the weaknesses in Western philosophy in a similar way, and Rosen provides tools for dealing with the problem. This introduction to the relationships between the thinking of these authors is meant to stimulate further discourse on the role of complex causal entailment in all areas of thought, and how it brings them together in a holistic worldview. The worldview built on complex causality is clearly distinct from that built around simple, direct causality. One important difference is that the impoverished causal

  17. Caracterização morfocultural e infecção cruzada de Colletotrichum gloeosporioides agente causal da antracnose de frutos e hortaliças em pós-colheita / Morfocultural characterization and cross infection Colletotrichum gloeosporioides causes anthracnose in fruits and vegetables post-harvested

    Directory of Open Access Journals (Sweden)

    Lucimar Pereira Bonett

    2010-12-01

    Full Text Available O fungo Colletotrichum gloeosporioides infecta uma grande variedade de plantas em regiões tropicais, subtropicais e temperadas ocasionando consideráveis perdas econômicas em doenças pré e pós-colheita. O objetivo deste trabalho foi caracterizar a morfologia e a infecção cruzada de isolados de Colletotrichum gloeosporioides obtidos de frutos e hortaliças em pós-colheita. Os isolados foram obtidos de lesões de frutos com sintomas de antracnose e cultivados em meio de cultivo BDA, sendo a avaliação do crescimento micelial realizada por meio de duas leituras diárias do diâmetro das colônias pelo período de quatorze dias e a caracterização morfológica das colônias realizada no final deste período. Para a realização do experimento, utilizou-se o delineamento experimental inteiramente casualisado com três repetições por tratamento. Para o experimento da infecção cruzada foram realizados dois ferimentos em frutos sadios nos quais foram depositados blocos de meio de cultura com 6 mm2 contendo os isolados. O delineamento experimental foi em esquema fatorial de 8 x 8, com quatro repetições. As médias de ambos os experimentos foram analisadas por meio do teste de Scott-Knott com 5% de probabilidade. A maioria dos isolados de C. gloeosporioides possuem grande potencial de infecção cruzada, já que foram capazes de causar lesões em frutos de mamão, manga, abacate, chuchu, jiló, pimentão verde e pimenta. Os isolados de frutos de mamão e abacate apresentaram o maior índice de crescimento micelial e os isolados provenientes do chuchu apresentaram o menor. Quanto ao desenvolvimento de lesões, o mamão apresentou-se mais suscetível, com lesões maiores, enquanto que a pimenta cambuci demonstrou-se a mais resistente, apresentando as menores lesões.

  18. Causality between Electricity Consumption & Economic growth : Empirical Evidence from India

    OpenAIRE

    Gupta, Geetu; Sahu, Naresh Chandra

    2009-01-01

    In this study ,an attempt has been made to investigate causality between electricity consumption and economic growth in India by adopting Granger Engel causality model for 1960-2006 period .Test results shows that electricity consumption has positive effect on economic growth. The paper support for the reforms in power sector and indicates that electricity act as a catalyst in realizing various social and economic goals.

  19. The role of causal links in performance measurement models

    OpenAIRE

    Kasperskaya, Yulia; Tayles, Michael

    2013-01-01

    Abstract Purpose: Several well-known managerial accounting performance measurement models rely on causal assumptions. Whilst users of the models express satisfaction and link them with improved organizational performance, academic research, of the realworld applications, shows few reliable statistical associations. This paper provides a discussion on the"problematic" of causality in a performance measurement setting. Design/methodology/approach: This is a conceptual study based on an analysis...

  20. Sensitivity analyses for parametric causal mediation effect estimation

    OpenAIRE

    Albert, Jeffrey M.; Wang, Wei

    2014-01-01

    Causal mediation analysis uses a potential outcomes framework to estimate the direct effect of an exposure on an outcome and its indirect effect through an intermediate variable (or mediator). Causal interpretations of these effects typically rely on sequential ignorability. Because this assumption is not empirically testable, it is important to conduct sensitivity analyses. Sensitivity analyses so far offered for this situation have either focused on the case where the outcome follows a line...

  1. The Direction of Causality between Insider Ownership and Market Valuation

    OpenAIRE

    Pedersen, Torben; Thomsen, Steen; Kvist, Hans Kurt

    2001-01-01

    The causal relationship between insider ownership and market valuation is tested on a database of the largest EU and US companies. Using a Granger causality test insider ownership (measured by the fraction of closely held shares) is found to have a negative effect on market valuation (measured as the simple Tobin's Q ratio). And market valuation is found to have a negative effect on insider ownership. Consistent with an overall non-linear relationship as hypothesised by Morck e...

  2. The Causal Relationship between Health and Education Expenditures in Malaysia

    OpenAIRE

    Chor Foon TANG; Yew Wah LAI

    2011-01-01

    A major macroeconomic policy in generating economic growth is to encourage investments on human capital such as health and education. This is because both health and education make significant contribution to increasing productivity of the labour force which ultimately exerts a positive effect on raising output levels. A question that arises is whether investments on health and education have a causal relationship and if so, what is the directional causality? The objective o...

  3. Causal Structure and Gravitational Waves in Brane World Cosmology

    OpenAIRE

    Ichiki, Kiyotomo; Nakamura, Kouji

    2003-01-01

    The causal structure of the flat brane universe of RSII type is re-investigated to clarify the boundary conditions for stochastic gravitational waves. In terms of the Gaussian normal coordinate of the brane, a singularity of the equation for gravitational waves appears in the bulk. We show that this singularity corresponds to the ``seam singularity'' which is a singular subspace on the brane universe. Based upon the causal structure, we discuss the boundary conditions for gravitational waves ...

  4. A Tool for Qualitative Causal Reasoning On Complex Systems

    OpenAIRE

    Tahar Guerram; Ramdane Maamri; Zaidi Sahnoun

    2010-01-01

    A cognitive map, also called a mental map, is a representation and reasoning model on causal knowledge. It is a directed, labeled and cyclic graph whose nodes represent causes or effects and whose arcs represent causal relations between these nodes such as "increases", "decreases", "supports", and "disadvantages". A cognitive map represents beliefs (knowledge) which we lay out about a given domain of discourse and is useful as a means of decision making support. There are several types of cog...

  5. Causal Linkages Between Domestic Terrorism and Economic Growth

    OpenAIRE

    Thomas Gries; Tim Krieger; Daniel Meierrieks

    2009-01-01

    We use the Hsiao-Granger method to test for growth-terrorism causality for seven Western European countries. In bivariate settings, the impact of economic performance on domestic terrorism is very strong. In trivariate settings, the impact of performance on terrorism diminishes. Here, we find that economic performance leads terrorist violence in robust ways only for three out of seven countries. Terrorism is almost never found to causally influence growth in bivariate and trivariate specifica...

  6. The Causal Relationship Between Government Revenue and Expenditure in Namibia

    OpenAIRE

    Eita, Joel Hinaunye; Mbazima, Daisy

    2008-01-01

    The relationship between government revenue and government expenditure is important, given its relevance for policy especially with respect to the budget deficit. The purpose of this paper is to investigate the relationship between government revenue and government expenditure in Namibia. It investigates the causal relationship between government revenue and government expenditure using Granger causality test through cointegrated vector autoregression (VAR) methods for the period the period 1...

  7. The causal effect of teen motherhood on worklessness

    OpenAIRE

    WALKER, Ian; Zhu, Yu

    2009-01-01

    Teen motherhood continues to be high in the US and the UK relative to most other western European countries. While recent research has clarified how effective policies to reduce teen motherhood might be (Kearney (2009)), there remains little evidence that quantifies the causal effects of teen motherhood on such mothers and their first born children. This paper provides estimates of the causal effect of teen motherhood on worklessness and does so by exploiting the availability of two sources o...

  8. Re-assessing causal accounts of learnt behavior in rats.

    Science.gov (United States)

    Burgess, K V; Dwyer, D M; Honey, R C

    2012-04-01

    Rats received either a common-cause (i.e., A→B, A→food) or a causal-chain training scenario (i.e., B→A, A→food) before their tendency to approach the food magazine during the presentation of B was assessed as a function of whether it was preceded by a potential alternative cause. Causal model theory predicts that the influence of an alternative cause should be restricted to the common-cause scenario. In Experiment 1, responding to B was reduced when it occurred after pressing a novel lever during the test phase. This effect was not influenced by the type of training scenario. In Experiment 2, rats were familiarized with the lever prior to test by training it as a potential cause of B. After this treatment, the lever now failed to influence test responding to B. In Experiment 3, rats given common-cause training responded more to B when it followed a cue that had previously been trained as a predictor of B, than when it followed another stimulus. This effect was not apparent in rats that received causal-chain training. This pattern of results is the opposite of that predicted by causal model theory. Thus, in three experiments, the presence of an alternative cause failed to influence test responding in manner consistent with causal model theory. These results undermine the application of causal model theory to rats, but are consistent with associative analyses. PMID:22486754

  9. Causal quantum theory and the collapse locality loophole

    International Nuclear Information System (INIS)

    Causal quantum theory is an umbrella term for ordinary quantum theory modified by two hypotheses: state vector reduction is a well-defined process, and strict local causality applies. The first of these holds in some versions of Copenhagen quantum theory and need not necessarily imply practically testable deviations from ordinary quantum theory. The second implies that measurement events which are spacelike separated have no nonlocal correlations. To test this prediction, which sharply differs from standard quantum theory, requires a precise definition of state vector reduction. Formally speaking, any precise version of causal quantum theory defines a local hidden variable theory. However, causal quantum theory is most naturally seen as a variant of standard quantum theory. For that reason it seems a more serious rival to standard quantum theory than local hidden variable models relying on the locality or detector efficiency loopholes. Some plausible versions of causal quantum theory are not refuted by any Bell experiments to date, nor is it evident that they are inconsistent with other experiments. They evade refutation via a neglected loophole in Bell experiments--the collapse locality loophole--which exists because of the possible time lag between a particle entering a measurement device and a collapse taking place. Fairly definitive tests of causal versus standard quantum theory could be made by observing entangled particles separated by ≅0.1 light seconds

  10. Florística e estrutura de comunidades arbóreas em cerrados de Rondônia,Brasil Flora and structure of tree communities in dry savannas in Rodônia, Brazil

    OpenAIRE

    Izildinha Souza Miranda; Samuel Soares Almeida; Paulo Jorge Dantas

    2006-01-01

    O cerrado constitui o segundo maior e mais diverso bioma brasileiro, configurando um heterogêneo mosaico fisionômico e florístico. Mais de seis mil espécies de fanerógamas são reportadas para o cerrado do Brasil Central. Este trabalho teve o objetivo de descrever e analisar a flora e a estrutura de quatro comunidades de árvores dos cerrados sensu latu do município de Vilhena, Rondônia, Brasil. As áreas estudadas foram: cerradão (Área 1), campo sujo (Área 2) e duas comunidades do cerrado sensu...

  11. Estudio de pre-factibilidad para la constitución de una sociedad de comercialización internacional (C.I) de productos florícolas

    OpenAIRE

    Giraldo Ríos, Juan Luis

    2010-01-01

    El presente trabajo “Estudio de pre-factibilidad para la constitución de una sociedad de comercialización internacional (C.I) de productos florícolas” tiene por objeto, como su titulo lo indica, realizar un estudio de pre-factibilidad técnica y económica para determinar la viabilidad de constituir una empresa de comercialización internacional, con el fin de exportar diversos tipos de flores, follajes, y arreglos florales a diferentes mercados.

  12. Estudo da biomassa e flora de estepes hidrófilas no Paraná em interação com o meio físico

    OpenAIRE

    Sousa, Letícia Penno de

    2013-01-01

    Resumo: Os objetivos desta pesquisa, realizada nos campos hidrófilos de altitude das nascentes do rio Caracará (Ponta Grossa/PR) e do rio da Dama (Palmas/PR), foram: (i) determinar sua composição florística e (ii) comparar a quantidade de biomassa aérea e subterrânea, bem como a decomposição da biomassa aérea, segundo diferentes grupos funcionais e condições físicas do ambiente. As áreas de estudo foram divididas em fisionomias e submetidas a levantamentos planialtimétricos, pedológicos e hi...

  13. Aspectos fitossociológicos de um fragmento da floresta natural de Astronium balansae engl., no município de Bossoroca, RS

    Directory of Open Access Journals (Sweden)

    Boligon Alexandra Augusti

    2005-01-01

    Full Text Available Este estudo objetivou conhecer a composição florística e a estrutura fitossociológica de um fragmento da Floresta Natural de Astronium balansae Engl., no município de Bossoroca, RS, Brasil. Foram demarcadas 7 unidades amostrais de 10x100m (1000m2 onde observou-se a ocorrência de 476 indivíduos com Circunferência à Altura do Peito (CAP = 30cm, distribuídos em 35 espécies e 25 famílias. As espécies mais características e importantes da floresta foram Astronium balansae, Myrcianthes pungens, Patagonula americana, Eugenia uniflora e Parapiptadenia rigida. As famílias Myrtaceae, Meliaceae e Euphorbiaceae foram as mais representativas do fragmento florestal estudado. O valor do Índice de diversidade de Shannon foi 3.

  14. Another(’s perspective on subjectivity in causal connectives: a usage-based analysis of volitional causal relations

    Directory of Open Access Journals (Sweden)

    Ninke Stukker

    2009-06-01

    Full Text Available Dans une hypothèse de catégorisation linguistique, les connecteurs de cause sont pris comme des outils de catégorisation. En effet, des études sur corpus suggèrent que les connecteurs sont fortement spécialisés dans une seule catégorie de causalité spécifique, mais aussi que leur usage n'est pas limité aux catégories de causalité auxquelles ils sont prototypiquement associés. Si nous supposons que le sens des connecteurs causaux peut être adéquatement décrit en référence à des catégories conceptuelles bien définies, comment pouvons-nous expliquer qu’il y ait une variation dans leur usage réel? Nous mettons l'accent sur les relations de cohérence causale volitionnelle, qui constituent le contexte d'usage prototypique du connecteur néerlandais daarom ‘c'est pourquoi’. Un autre moyen d’expression des relations causales volitionnelles est le recours au connecteur dus ‘alors/donc’ qui est prototypiquement utilisé dans les relations de causalité épistémique. Notre hypothèse est que les relations de causalité volitionnelle exprimées par daarom vs dus diffèrent systématiquement en termes de subjectivité. Nous proposons un modèle d'analyse qui contient de multiples opérationnalisation de la notion de subjectivité et une distinction entre différents niveaux de complexité (sous-clause, clause, et discours. Nous constatons que les relations causales volitionnelles en dus contiennent plus souvent des éléments subjectifs que les relations causales volitionnelles en daarom. Nous interprétons cette distribution au sein d'un cadre théorique fondé sur l'usage (usage-based framework, et nous proposons d'analyser les cas volitionnels de dus comme des instanciations non-prototypiques du sens de dus,qui est donc intrinsèquement subjectif et prototypiquement épistémique.Under a linguistic categorization hypothesis causal connectives are taken as categorization devices. Indeed, corpus studies suggest that

  15. Ordem temporal e inferência causal

    Directory of Open Access Journals (Sweden)

    Warren E. Miller

    2001-11-01

    Full Text Available Medidas de mudança em pares de variáveis atitudinais podem proporcionar insights Importantes sobre a estrutura dos sistemas de crenças políticas dos públicos de massa. Dados de painéis revelam evidências da grande centralidade de alguns elementos de idéias em vez de outros no contexto de constrangimento dinâmico de curto prazo. A especificação dos atributos teoricamente relevantes dos eleitores torna possível testar diferenças estruturais esperadas que conectam predisposições relacionadas a políticas e preferências por políticas; a especificação também torna possível testar proposições que envolvem os efeitos recíprocos de atitudes e preferências emergentes de voto. Algumas das especificações mais úteis revelam até que ponto a heterogeneidade da população produz uma imagem embaçada de relações quando a análise se baseia no eleitorado total, em vez de se limitar a eleitores ou subconjuntos de eleitores especificados por critérios teóricos.Measures of change in pairs of attitudinal variables can provide important insights into the structure of the political belief systems of mass publics. Panel data reveal evidence of the greater centrality of some idea elements rather than others in the context of short-term dynamic constraint. Specification of the theoretically relevant voter attributes makes it possible to test for expected structural differences connecting policy related pre-dispositions and policy preferences; specification also makes it possible to test propositions involving the reciprocal effects of attitudes and emerging vote preferences. Some of the more helpful specifications disclose the extent to which population heterogeneity produces a blurred image of relationships when analysis is based on the total electorate rather than limited to voters or subsets of voters specified by theoretical criteria.

  16. Enhancing scientific reasoning by refining students' models of multivariable causality

    Science.gov (United States)

    Keselman, Alla

    Inquiry learning as an educational method is gaining increasing support among elementary and middle school educators. In inquiry activities at the middle school level, students are typically asked to conduct investigations and infer causal relationships about multivariable causal systems. In these activities, students usually demonstrate significant strategic weaknesses and insufficient metastrategic understanding of task demands. Present work suggests that these weaknesses arise from students' deficient mental models of multivariable causality, in which effects of individual features are neither additive, nor constant. This study is an attempt to develop an intervention aimed at enhancing scientific reasoning by refining students' models of multivariable causality. Three groups of students engaged in a scientific investigation activity over seven weekly sessions. By creating unique combinations of five features potentially involved in earthquake mechanism and observing associated risk meter readings, students had to find out which of the features were causal, and to learn to predict earthquake risk. Additionally, students in the instructional and practice groups engaged in self-directed practice in making scientific predictions. The instructional group also participated in weekly instructional sessions on making predictions based on multivariable causality. Students in the practice and instructional conditions showed small to moderate improvement in their attention to the evidence and in their metastrategic ability to recognize effective investigative strategies in the work of other students. They also demonstrated a trend towards making a greater number of valid inferences than the control group students. Additionally, students in the instructional condition showed significant improvement in their ability to draw inferences based on multiple records. They also developed more accurate knowledge about non-causal features of the system. These gains were maintained

  17. UMA TEORÍA CAUSAL PARA LOS CASOS FREGE

    Directory of Open Access Journals (Sweden)

    ABEL WAJNERMAN PAZ

    2015-06-01

    Full Text Available Fodor ha argumentado a favor de un par de tesis que pueden caracterizarse como constituyendo un dilema: Por un lado, si adoptamos una teoría funcional para los conceptos explicamos semánticamente los casos Frege pero caemos en el holismo semántico. Por otro lado, si adoptamos una teoría causal/informacional evitamos el holismo pero no explicamos los casos Frege semánticamente. Fodor (por ej, 1994, 1998 y 2008 intenta evitar la segunda parte del dilema argumentando que los casos de Frege pueden tener una explicación sintáctica y no semántica. En este trabajo intentaré ofrecer una salida alternativa al dilema fodoriano. Propondré una explicación semántica de los casos Frege que incorpora tanto elementos de una teoría causal como de una de rol funcional. Afirmaré que el contenido cognitivo o estrecho de un concepto (el tipo de contenido aparentemente exigido por los casos Frege es el conjunto de contenidos causales/informacionales de las representaciones que figuran en su rol funcional. Considero que individuar a las representaciones en los roles por medio de sus contenidos causales permite evitar el holismo (evitando el proceso de ramsificación típicamente empleado para individuar a los roles y que identificar el contenido cognitivo con contenidos causales/informacionales de las representaciones en los roles permite evitar el referencialismo de las propuestas causales (podemos distinguir sentido de referencia en términos causales.

  18. General solutions and causality for a Voigt medium

    Energy Technology Data Exchange (ETDEWEB)

    Duren, R.E.; Heestand, R.L. [Exxon Production Co., Houston, TX (United States)

    1995-01-01

    A 1-D wave equation solution for a propagating seismic pulse in a Voigt medium can be obtained by using a separation of variables to find time harmonic particular solutions and then superimposing the particular solutions. This superposition is a time convolution of the boundary condition (or incident pulse) and the medium`s impulse response. Even though causality is not introduced during the solution of the wave equation, the general solution is causal since the boundary condition is causal and the medium`s impulse response can be shown to be causal. The relationship between attenuation and phase velocity as well as their dependence on frequency arise from the form chosen for the particular solutions. The arbitrary constants associated with the particular solutions are determined by the boundary condition, and the initial condition is also dependent on the boundary condition; however, the initial condition is properly determined and does not depend on times after the initial time (thereby satisfying causality). The convolutional nature of the general solution allows it to also be expressed as a time convolution of the boundary conditions`s time derivative and the medium`s step function response. This expression can be viewed as a superposition of step function responses where the step function response is a particular solution to the wave equation obtained using an approach that is similar to one recently developed for propagating electric pulses. This new solution is obtained with the initial and boundary conditions being independently introduced during the solution of the wave equation. There is no frequency dependence in this solution, and the general solution is causal since it is a superposition of causal step function responses.

  19. Caracterização fitofisionômica e levantamento florístico preliminar no Pantanal dos Rios Mortes-Araguaia, Cocalinho, Mato Grosso, Brasil Vegetation types and preliminary floristic survey in the Mortes-Araguaia Pantanal, Cocalinho, Mato Grosso, Brazil

    Directory of Open Access Journals (Sweden)

    Beatriz Schwantes Marimon

    2001-08-01

    Full Text Available O presente estudo realizou-se no Pantanal dos Rios Mortes-Araguaia, extensa planície inundável localizada no municípo de Cocalinho, nordeste de Mato Grosso, Brasil. Efetuou-se uma caracterização fitofisionômica e um levantamento florístico preliminar da região. Foram selecionados três Sítios, com fitofisionomias representativas: proximidades do Rio das Mortes (12° 37'S; 50° 55'W, foz do Rio das Mortes com o Araguaia (11° 54'S; 50° 48'W e porção mediana do Rio Cristalino (12° 52'S; 50° 49'W. O método de amostragem adotado foi o de levantamentos rápidos. Foram identificadas oito fitofisionomias: Mata Inundável, Caapão, Babaçual, Cerradão, Cerrado stricto sensu, Campo de Murunduns, Campo de Byrsonima orbignyana e Campo Cerrado de Vochysia rufa. Foram levantadas 248 espécies de árvores, arbustos, sub-arbustos e lianas, distribuídas em 158 gêneros e 62 famílias. As fitofisionomias apresentaram um padrão heterogêneo, sendo que nenhuma das espécies ocorreu em todas elas. Porém, Alibertia edulis (L. Rich. A. Rich., Andira cuyabensis Benth., Maprounea guianensis (Aubl. M. Arg., entre outras, ocorreram em seis das oito fitofisionomias. As famílias com maior riqueza foram: Caesalpiniaceae, Annonaceae e Myrtaceae. Ocorreram algumas semelhanças florísticas com o Pantanal do Rio Paraguai, porém, são necessários estudos mais aprofundados para confirmar. Os padrões de heterogeneidade fitofisionômica indicam que a área estudada necessita de medidas conservacionistas.This study was carried out in the Pantanal of the Mortes and Araguaia rivers, a flooded plain located in Cocalinho, northeastern Mato Grosso, Brazil. The objectives of this study were to conduct a preliminary survey of the flora and to characterize the vegetation types. Three representative sites were selected: one near Rio das Mortes (12° 37'S; 50° 55'W, one at the mouth of Araguaia and Mortes rivers (11° 54'S; 50° 48'W and one in the middle portion of

  20. The Shared Causal Pasts and Futures of Cosmological Events

    CERN Document Server

    Friedman, Andrew S; Gallicchio, Jason

    2013-01-01

    We derive criteria for whether two cosmological events can have a shared causal past or a shared causal future, assuming a Friedmann-Lemaitre-Robertson-Walker universe with best-fit \\Lambda CDM cosmological parameters from the Planck satellite. We further derive criteria for whether either cosmic event could have been in past causal contact with our own worldline since the time of the hot "big bang", which we take to be the end of early-universe inflation. We find that pairs of objects such as quasars on opposite sides of the sky with redshifts z >= 3.65 have no shared causal past with each other or with our past worldline. More complicated constraints apply if the objects are at different redshifts from each other or appear at some relative angle less than 180 degrees, as seen from Earth. We present examples of observed quasar pairs that satisfy all, some, or none of the criteria for past causal independence. Given dark energy and the recent accelerated expansion, our observable universe has a finite conform...