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Sample records for agente causal da

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

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    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.

  2. 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

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    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

  3. 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

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

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    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.

  5. 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

  6. 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 ...

  7. 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

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    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.

  8. 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

  9. In vivo sensitivity reduction of Puccinia triticina races, causal agent of wheat leaf rust, to DMI and QoI fungicides Redução da sensibilidade de raças de Puccinia triticina, agente causal da ferrugem da folha do trigo, aos fungicidas DMI e QoI, in vivo

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    Gisele da Silva Arduim

    2012-12-01

    Full Text Available Experiments were carried out to determine in vivo the IC50 and the IC90 for demethylation-inhibitor fungicides (DMIs, triazoles and quinone outside inhibitors (QoIs, strobilurins to the five most frequent races of Puccinia triticina in 2007 growing season in Southern Brazil. The tests were done in a greenhouse with wheat seedlings. DMI fungicides were tested at the concentrations, in mg/L, 0.0; 0.02; 0.2; 2.0; 20.0; 100.0 and 200.0, and QoIs at the concentrations 0.0; 0.0001; 0.001; 0.01; 0.1; 1 and 10.0 mg of active ingredient/L water. Fungicides were preventively applied at 24 hours before the inoculation of seedlings with the fungal spores. The effect of treatments was assessed based on the number of uredia/cm². The lowest IC50 (inhibitory concentration for DMI fungicides determined for MCG-MN, sensitive race, ranged from 0.33 to 0.91 mg/L, while the highest values for MDP-MR, MDT-MR, MDK-MR, MFH-HT races, varied from 9.63 to 85.64 mg/L (suspected insensitivity. QoI fungicide presented an IC50 varying from 0.0018 to 0.14 mg/L. The sensitivity reduction factor for DMIs varied from 8.8 to 238.8, and for QoIs from 0.3 to 1.5 mg/L. Sensitivity reduction was confirmed for the races MDP-MR, MDT-MR, MDK-MR, MFH-HT to DMIs, as well as their sensitivity to QoI fungicides.Experimentos foram conduzidos para determinar, in vivo a IC50 e CI90 para fungicidas inibidores da demetilação (IDM(triazois e inibidores da quinona externa (IQe (estrobilurinas a cinco raças de Puccinia triticina mais frequentes na safra 2007, no Sul do Brasil. Os experimentos foram realizados em câmara de crescimento com plântulas de trigo. Os fungicidas IDMs foram testados nas concentrações em mg/L de 0,0; 0,02; 0,2; 2,0; 20,0; 100,0 e 200,0 e os IQes nas concentrações de 0,0; 0,0001; 0,001; 0,01; 0,1, 1 e 10,0 mg de ingrediente activo/L de água. Os fungicidas foram aplicados preventivamente 24 horas antes da inoculação das plântulas com os esporos do fungo. O efeito

  10. 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...

  11. Stenotrophomonas maltophilia: a new potential biocontrol agent of Ralstonia solanacearum, causal agent of potato brown rot

    NARCIS (Netherlands)

    Messiha, N.A.S.; Diepeningen, van A.D.; Farag, N.S.; Abdallah, S.A.; Janse, J.D.; Bruggen, van A.H.C.

    2007-01-01

    Stenotrophomonas maltophilia was isolated from the rhizosphere of eggplant in the Nile Delta of Egypt, and its antagonistic potential against Ralstonia solanacearum race 3 biovar 2, the causal agent of potato brown rot, was in vitro evaluated on KB agar medium and in vivo on potato plants. In vitro,

  12. Experimental and causal view on information integration in autonomous agents

    OpenAIRE

    Geiger, Philipp; Hofmann, Katja; Schölkopf, Bernhard

    2016-01-01

    The amount of digitally available but heterogeneous information about the world is remarkable, and new technologies such as self-driving cars, smart homes or the "internet of things" will further increase it. In this paper we examine certain aspects of the problem of how such heterogeneous information can be harnessed by intelligent agents. We first discuss potentials and limitations of some existing approaches, followed by two investigations. The focus of the first investigation is on using ...

  13. Executive Emotional System Disruption as Causal Agent in Frontal Lobishness among Abused Children

    Science.gov (United States)

    Naude, H.; Du Preez, C. S.; Pretorius, E.

    2004-01-01

    This article aims to explore Executive Emotional System (EES) disruption as causal agent in frontal lobishness among abused children. The "Revised Senior South African Individual Scale" (SSAIS-R) was used to assess a sample population of seventy-five male and female subjects between the ages of 8 years 0 months and 16 years 11 months who were…

  14. Occupational Asthma: New Low-Molecular-Weight Causal Agents, 2000–2010

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    J. A. Pralong

    2012-01-01

    Full Text Available Background. More than 400 agents have been documented as causing occupational asthma (OA. The list of low-molecular-weight (LMW agents that have been identified as potential causes of OA is constantly expanding, emphasizing the need to continually update our knowledge by reviewing the literature. Objective. The objective of this paper was to identify all new LMW agents causing occupational asthma reported during the period 2000–2010. Methods. A Medline search was performed using the keywords occupational asthma, new allergens, new causes, and low-molecular-weight agents. Results. We found 39 publications describing 41 new LMW causal agents, which belonged to the following categories: drugs (n=12, wood dust (n=11, chemicals (n=8, metals (n=4, biocides (n=3, and miscellaneous (n=3. The diagnosis of OA was confirmed through SIC for 35 of 41 agents, peak expiratory flow monitoring for three (3 agents, and the clinical history alone for three (3 agents. Immunological tests provided evidence supporting an IgE-mediated mechanism for eight (8 (20% of the newly described agents. Conclusion. This paper highlights the importance of being alert to the occurrence of new LMW sensitizers, which can elicit OA. The immunological mechanism is explained by a type I hypersensitivity reaction in 20% of all newly described LMW agents.

  15. Control of Ralstonia Solanacearum The Causal Agent of Brown Rot in Potato Using Essential Oils

    International Nuclear Information System (INIS)

    Five essential oils, namely peppermint (Mentha piperita L.), caraway (Carium carvum L.), fennel (Foeniculum vulgare Mill.), lemongrass (Cymbopogon citratus Staph.) and thyme (Thymus vulgaris), were used separately against Ralstonia solanacearum; the causal agent of brown rot in potato. The most two effective oils (peppermint and thyme) were used in vitro and in vivo after testing their effects on potato tubers buds germination. Peppermint inhibited buds germination but thyme have no effects on buds germination. In vivo, the control of brown rot using thyme oil in glass house experiment reduced the percentage of brown rot infection to 30.6% and reduced the severity of disease from 5 to 3.

  16. Survival of Fusarium graminearum, the causal agent of Fusarium head blight. A review

    OpenAIRE

    Leplat, Johann; Friberg, Hanna; Abid, Muhammad; Steinberg, Christian

    2013-01-01

    Wheat is one of the most cultivated crops worldwide. In 2010, 20 % of wheat and durum wheat were cultivated in Europe, 17 % in China and 9 % in Russia and in North America. Wheat yield can be highly decreased by several factors. In particular Fusarium graminearum Schwabe is a worldwide fungal pest impacting wheat production. F. graminearum is the causal agent of Fusarium head blight, root and stem-base rot of cereals. Losses caused by Fusarium head blight in Northern and Central America from ...

  17. Is diabetes a causal agent for colorectal cancer? Pathophysiological and molecular mechanisms

    Institute of Scientific and Technical Information of China (English)

    Olga Giouleme; Michael D Diamantidis; Marios G Katsaros

    2011-01-01

    The possible relationship between diabetes mellitus (DM) and colorectal cancer (CRC), concerning pathophysiological and molecular mechanisms is highlighted in this review. The most recent and complete articles and developments in this particular field were thoroughly reviewed. Common risk factors, such as obesity, sedentary lifestyle, and Western diet between DM and CRC, led to the theory that DM might be a causal agent for CRC development. Various studies have connected type 2 DM and CRC, either proximal or distal, in both sexes. Additionally, chronic insulin treatment has been linked with increased colorectal tumor risk among type 2 diabetic patients. Interestingly, elevated hemoglobin A1c has been proven to be an independent predictor of aggressive clinical behavior in CRC patients. These mechanisms include the insulin-like growth factor-hyperinsulinemia theory and the participation of oncogenic intracellular signaling pathways. Furthermore, it has been proposed that Cox-2 inhibitors might have a role in decreasing the incidence of CRC. Finally, the use of statins to reduce the risk for colon cancer in patients with diabetes has remained controversial. Diabetic patients over 50 should receive counseling regarding their elevated risk for CRC, and screening colonoscopy should be recommended before initiating insulin therapy. However, there are no current guidelines, and this strategy is not yet applicable to some countries, as the corresponding risk would not allow screening colonoscopy to be adopted. There is strong evidence to indicate that DM is a causal agent for CRC development. This conclusion provides new impetus for re-evaluating CRC screening worldwide.

  18. Molecular Detection of Monilinia fructigena as Causal Agent of Brown Rot on Quince

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    Jovana Hrustić

    2012-01-01

    Full Text Available Species of the genus Monilinia are important causal agents of fruit rot on pome and stone fruits in Serbia. The pathogen is very harmful, especially on small properties and cottage plantations where intensive control measures are not applied. Quince is importanthost for the pathogens of this genus. During spring 2010, intensive occurrence of mummified fruits overwintering on branches of the quince was observed. The pathogen was isolated using standard phytopathological methods. Pathogenicity of eight obtained isolates was tested by artificial inoculation of injured apple fruits. Identification was performed according to pathogenic, morphological and ecological properties, and was confirmed by Multiplex polimeraze chain reaction, PCR. All the isolates studied caused brown rot on inoculated apple fruits. The isolates form light yellow colonies with lobate margins,with single-celled, transparent, elliptical or oval conidia in chains, regardless temperature or light presence. Sclerotia are observed in 14 days old cultures. The highest growth rate of most of the isolates is at 27°C and in dark. Based on studied pathogenic, morphological and ecological characteristics, it was found that the Monilinia fructigena is causal agent of brown rot of quince. Using specific primers (MO368-5, MO368-8R, MO368-10R, Laxa-R2for detection of Monilinia species in Multiplex PCR reaction, the expected fragment 402 bp in size was amplified, which confirmed that the studied isolates belonged to the speciesM. fructigena.

  19. 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.

  20. ‘Candidatus Liberibacter asiaticus’, Causal Agent of Citrus Huanglongbing, Is Reduced by Treatment with Brassinosteroids

    Science.gov (United States)

    Hernández, Ingrid; Portieles, Roxana; Rodríguez García, Mayra; López, Yunior; Aranguren, Miguel; Alonso, Eugenio; Delgado, Roger; Luis, Maritza; Batista, Lochy; Paredes, Camilo; Rodríguez, Meilyn; Pujol, Merardo; Ochagavia, María Elena; Falcón, Viviana; Terauchi, Ryohei; Matsumura, Hideo; Ayra-Pardo, Camilo; Llauger, Raixa; Pérez, María del Carmen; Núñez, Mirian; Borrusch, Melissa S.; Walton, Jonathan D.; Silva, Yussuan; Pimentel, Eulogio; Borroto, Carlos; Borrás-Hidalgo, Orlando

    2016-01-01

    Huanglongbing (HLB) constitutes the most destructive disease of citrus worldwide, yet no established efficient management measures exist for it. Brassinosteroids, a family of plant steroidal compounds, are essential for plant growth, development and stress tolerance. As a possible control strategy for HLB, epibrassinolide was applied to as a foliar spray to citrus plants infected with the causal agent of HLB, ‘Candidatus Liberibacter asiaticus’. The bacterial titers were reduced after treatment with epibrassinolide under both greenhouse and field conditions but were stronger in the greenhouse. Known defense genes were induced in leaves by epibrassinolide. With the SuperSAGE technology combined with next generation sequencing, induction of genes known to be associated with defense response to bacteria and hormone transduction pathways were identified. The results demonstrate that epibrassinolide may provide a useful tool for the management of HLB. PMID:26731660

  1. Integrated Management of Causal Agents of Postharvest Fruit Rot of Apple

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    Mila Grahovac

    2011-01-01

    Full Text Available One of the major causes of poor quality and fruit loss (during storage and transportare diseases caused by phytopathogenic fungi. Economic losses which are the consequenceof the phytopathogenic fungus activity after harvest exceed the losses in the field.Themost important postharvest fungal pathogens of apple fruits are: Botrytis cinerea Pers. exFr., Penicillium expansum (Lk. Thom., Cryptosporiopsis curvispora (Peck. Grem., Colletotrichumgloeosporioides (Penz. Sacc., Monilinia sp., Gloeosporium album Osterw, Alternaria alternata(Fr. Keissler, Cladosporium herbarium Link., Cylindrocarpon mali (Alles. Wollenw., Stemphyliumbotryosum Wallr. The use of available protection technologies can significantly reducelosses caused by pathogens in storage. The concept of integrated pest management (IPMin apple fruits i.e. sustainable approach in control of causal agents of postharvest fruit rot,using cultural, physical, biological and chemical measures, to minimize economic, healthand risks to consumers and environment, is presented in the paper.

  2. Identification and Control of Cladobotryum spp., Causal Agents of Cobeweb Disease of Cultivated Mushroom

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    Ivana Potočnik

    2009-01-01

    Full Text Available Cladobotryum spp. are causal agents of cobweb disease, one of the most serious diseases of cultivated mushroom (Agaricus bisporus (Lange Imbach in Serbia and worldwide, which affects product quality and yield. The disease symptoms are: cottony fluffy white oryellowish to pink colonies on mushroom casing, rapid colonization of casing surface, covering of host basidiomata by mycelia, and their decay. Prochloraz-Mn has been officially recommended for mushroom cultivation in EU countries. However, inefficiency of prochloraz-Mn has been noted at a level of spotting symptoms of cobweb disease. With regard to cases of resistance evolution and a general threat to the environment and human health, special attention should be focused on good programmes of hygiene, and inventing and developing alternative methods of disease control.

  3. Role of Amblyomma lepidum in the transmission of Mycobacterium farcinogenes, the causal agent of Bovine farcy

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    Eltayib Badowi Hasabelrasoul

    2015-06-01

    Full Text Available The present study was conducted to investigate the role of Amblyomma lepidum in the transmission of Mycobacterium farcinogenes, the causal agent of bovine farcy in Sudan. A total of 22 samples comprising of prescapular, submaxillary, mediastinal, parotid, retropharengeal and pulmonary lymph nodes, and subcutaneous nodules were collected for this study. M. farcinogenes was successfully isolated from the specimens by following traditional bacteriological techniques, and the bacteria were identified using standard biochemical assays, lipid analysis using Thin Layer Chromatography, and duplex Polymerase Chain Reaction. Larvae and nymphs of A. lepidum acquired M. farcinogenes from experimentally infected rabbits, and subsequently transmitted the infection to fresh rabbits within a maximum period of ten weeks. In contrast, adult A. lepidum failed to contract the organism from the infected rabbits; so, trans-ovarian transmission could be ruled out. In conclusion, this study confirmed the trans-stadial transmission of M. farcinogenes through larvae and nymphs of A. lepidum.

  4. 'Candidatus Liberibacter asiaticus', Causal Agent of Citrus Huanglongbing, Is Reduced by Treatment with Brassinosteroids.

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    Eduardo Canales

    Full Text Available Huanglongbing (HLB constitutes the most destructive disease of citrus worldwide, yet no established efficient management measures exist for it. Brassinosteroids, a family of plant steroidal compounds, are essential for plant growth, development and stress tolerance. As a possible control strategy for HLB, epibrassinolide was applied to as a foliar spray to citrus plants infected with the causal agent of HLB, 'Candidatus Liberibacter asiaticus'. The bacterial titers were reduced after treatment with epibrassinolide under both greenhouse and field conditions but were stronger in the greenhouse. Known defense genes were induced in leaves by epibrassinolide. With the SuperSAGE technology combined with next generation sequencing, induction of genes known to be associated with defense response to bacteria and hormone transduction pathways were identified. The results demonstrate that epibrassinolide may provide a useful tool for the management of HLB.

  5. The causal agents of damping-off disease of buglosse from Iran.

    Science.gov (United States)

    Okhovvat, S M; Zakeri, Z; Moshashai, R

    2005-01-01

    Iran is considered a major genetic for medicinal plant in the world. Because of this significant diversity and historical background in identification and utilization to remedy human and animal diseases, export of medicinal plant can help to strengthen local as well as natural economy. Buglosse (Fig. 1) is one of the most important and common medicinal plants in Iran and exist as Echium amoneum and Borago officinalis. This work was conducted in order to identify the causal agent(s) of damping off disease in buglosse. Plant disease samples were taken from Esfahan and Tehran provinces. Symptoms on original plant including root, crown rot, dark tissue, pith and hallow root were collected in order to isolate disease agent(s). Symptomatic root and crown tissues after surface sterilization with 96% ethanol were transferred on to PDA and WA media and also on moist filter paper in petri dishes. Two fungal colonies grew from tissue segments and spore culture was subsequently purified. The fungal isolate identified as Rhizoctonia solani based on the following test. Hyphal tip was removed from colony margin placed on PDA and PSA media and incubated in dark. Colony diameter of one hundred hyphae measured and nucleus was stained according to Bandoni (1979), Kronland and Stanghellini (1988). It was observed that in each cell of hyphae there are more than two nuclei. Single spore culture were obtained from macroconidia of Fusarium isolate. After 24 hr of incubation, growing single spore were transferred to KCL medium to detect spore chains. Fungal isolates transferred to PSA and PDA media for sporulation. After 7 days colonies appeared as white cream to pinkish on top and cream to dark pink at the bottom of petri dish with abundant micro and macro conidia. Colonies were snow white, felting shape, with ample causal hyphae on PSA medium. On KCL medium, fungal growth was superficial and colonies were colorless with long macroconidia and individual sausage-shape macroconidia being

  6. White rot of garlic and onion (Causal agent, Sclerotium cepivorum): A status report from the Pacific Northwest

    Science.gov (United States)

    There is evidence from literature, state department of agriculture documents, and recent diagnoses that Sclerotium cepivorum, causal agent of white rot of garlic and onion, is spreading and/or becoming more established in the Pacific Northwest. Previously documented distributions are summarized, an...

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

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    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

  8. Tetranychus urticae (Acari: Tetranychidae) transmits Acidovorax citrulli, causal agent of bacterial fruit blotch of watermelon.

    Science.gov (United States)

    Choi, Okhee; Park, Jung-Joon; Kim, Jinwoo

    2016-08-01

    The two-spotted spider mite (TSSM) Tetranychus urticae is one of the most important pests of cucurbit plants. If TSSM can act as vector for Acidovorax citrulli (Acc), causal agent of bacterial fruit blotch (BFB), then the movement of mites from infected to healthy plants may represent a potential source of inocula for BFB outbreaks. To confirm the association between Acc and TSSM, we generated a green fluorescent protein-tagged mutant strain (Acc02rf) by transposon mutagenesis and demonstrated that TSSM can transmit Acc from infected to non-infected watermelon plants. Challenge with 10 TSSMs carrying Acc02rf population densities of 1.3 × 10(3) CFU each on freshly grown individual watermelon plants caused disease transmission to 53 %. Incubation periods ranged 7-9 days. Bacteria recovered from symptoms typical of those associated with leaf necrosis were characterized and identified as Acc. To our knowledge, this is the first report showing that TSSM can be a vector of Acc. The results reported here support that the strong association of TSSM with Acc is of particular importance in controlling BFB. PMID:27178042

  9. Erwinia amylovora – the Causal Agent of Root Collar Necrosis of Apple Trees

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    Veljko Gavrilović

    2008-01-01

    Full Text Available A large-scale outbreak of fire blight symptoms caused by Erwinia amylovora was recorded in pome fruit trees during 2007. In addition to fruit necrosis and shoot blight as the typical disease symptoms, dark purple necrosis was observed in the root collar area girdling the trunk just above the ground and thus withering the whole apple tree. Since similar symptoms on apple trees could be caused by E. amylovora or one of several phytopathogenic fungi of the genera Phomopsis and Phytophthora, an investigation was conducted to identify the causal agent of this disease. Levan-producing, nonfluorescent bacteria were isolated from diseased samples. The isolated strains produced HR in tobacco leaves and necrosis of artificially inoculated, immature pear fruits, followed by oozing of bacterial exudate, a characterisitic of E. amylovora. Based on the results of pathogenicity tests, biochemical characteristics, ELISA test and PCR analysis, it was confirmed that the investigated strainsbelonged to E. amylovora, causing the root collar necrosis of apple trees as an atypical symptom of this bacterium in Serbia. The explanation of this symptom may be that the vegetative rootstocks were infected with E. amylovora. Therefore, the development of diagnostic protocols for detection of E. amylovora in apple rootstock is very important for health inspections of planting materials.

  10. Characterization, In Vitro Culture, and Molecular Analysis of Thecaphora solani, the Causal Agent of Potato Smut.

    Science.gov (United States)

    Andrade, Orlando; Muñoz, Gastón; Galdames, Rafael; Durán, Paola; Honorato, Rodrigo

    2004-08-01

    ABSTRACT The fungus Thecaphora solani (syn.: Angiosorus solani), the causal agent of potato smut, was cultivated in vitro for the first time. Teliospores obtained from galls of infected potato plants were used to inoculate commonly used solid and liquid media. The teliospores produced two kinds of vegetative tissue depending on the nutrient status of the media. A very slow radial-growing, hyaline, and septate mycelium, as usually seen in most of the in vitro-cultivated filamentous fungi, was obtained in wateragar medium after 30 to 40 days. On the other hand, a white, sponge-like mycelial mass was obtained in HCM + 1% activated charcoal, and on common potato dextrose agar or malt-yeast-peptone solid or liquid media, after 40 to 50 days under lab conditions. The identity among teliospores and the sponge-like mycelial mass was corroborated by DNA fingerprinting and partial sequencing of the large subunit (LSU) rDNA region. The sexual cycle of the pathogen was completed under lab conditions based on the development of teliospores on the sponge-like mycelial mass. The first attempt to reproduce the disease under controlled conditions was successful, inducing a gall in a cv. Desirée potato explant cultivated in vitro inoculated with radial-growing mycelia. Phylogenetic analysis of LSU rDNA data of the genus Thecaphora and other smut fungi confirmed the initial classification of the pathogen as T. solani. PMID:18943109

  11. Biocontrol of Rhizoctonia solani, the causal agent of bean damping-off by fluorescent pseudomonads.

    Science.gov (United States)

    Afsharmanesh, H; Ahmadzadeh, M; Sharifi-Tehrani, A

    2006-01-01

    Rhizosphere bacteria belonging to the fluorescent pseudomonads are receiving increasing attention for the protection of plants against soil-borne fungal pathogens. Among these pathogens, Rhizoctonia solani, the causal agent of bean damping- off is very important in bean fields of Iran. In this study, the antagonistic activity of 46 isolates of fluorescent pseudomonads (isolated from different area of Iran) and Pseudomonas fluorescens strain CHA0 investigated against one isolate of R. solani. About 64% of isolates revealed antagonistic activity against R. solani. Production of antifungal metabolites such as HCN, siderophore and protease was evaluated. The results showed that 97.8%, 17% and 78% of isolates produced siderophore, HCN and protease respectively. There was no significant correlation between antagonistic activity and production of these metabolites. Isolates P-5, P-10 and P-32 with strain CHA0 were selected in order to investigate involvement of siderophore, volatile metabolites (HCN), and non-volatile metabolites in reducing mycelial growth of R. olani. Isolate P-5 showed much more inhibitory effect by production of volatile metabolites and siderophore. Non-volatile metabolites in isolates P-32 and P-5 completely inhibited mycelial growth of the fungus. After the primary labrotory tests, isolates P-14, P-35, P-30, P-5 and strain CHA0 were selected for in vivo experiments. These selected isolates with benomyl fungicide were used as seed coating and soil drenching in sterile soil under greenhouse condition. The result indicated that in seed treatment method, isolates P-30 by 66% had the most effect in disease reduction while in soil treatment method, strain CHAO by 60% had the most effect, such that this two isolates showed significant differences in comparison with plants inoculated with R. solani inoculums. PMID:17390854

  12. Murcha do manjericão (Ocimum basilicum no Brasil: agente causal, círculo de plantas hospedeiras e transmissão via semente Sweet basil (Ocimum basilicum wilt in Brazil: causal agent, host range and seed transmission

    Directory of Open Access Journals (Sweden)

    Ailton Reis

    2007-06-01

    Full Text Available O manjericão (Ocimum basilicum L. é uma hortaliça da família Lamiaceae, utilizada na culinária ou como matéria prima para a indústria de fármacos e óleos essenciais. Amostras de plantas de manjericão apresentando sintomas de murcha, seca de hastes e podridão de colo foram coletadas na área rural de Brazlândia (DF durante a estação chuvosa de 2005. Outras duas amostras foram coletadas em plantas cultivadas em campo aberto e casas de vegetação na região de Ponte Alta (DF. Isolados de um fungo, identificado como Fusarium oxysporum, foram obtidos em todas as amostras. Testes de patogenicidade foram conduzidos com mudas das cultivares O. basilicum 'Dark Opal' e 'Italian Large Leaf', e de acessos das espécies O. americanum L. (manjericão de folha miúda, O. campechianum Mill. (alfavaca, Origanum manjorana L. (manjerona, Origanum vulgare L. (orégano, Mentha arvensis L. (menta, Coleus blumei Benth. (tapete, Leonorus sibiricus L. (rubim e Leonotis nepetaefolia (L. W.T. Aiton (cordão-de-frade. Todos os isolados fúngicos mostraram-se altamente virulentos sobre as duas cultivares de manjericão. Em O. campechianum e O. americanum os isolados causaram apenas suave escurecimento vascular e leve redução de crescimento, sendo avirulentos sobre acessos das espécies O. manjorana, O. vulgare, M. arvensis, C. blumei, L. sibiricus e L. nepetaefolia. Este conjunto de dados indicou que o agente causal da doença é o fungo F. oxysporum f. sp. basilici, constituindo-se no primeiro registro formal deste patógeno no Brasil. Os lotes de sementes utilizados nas áreas de ocorrência da doença foram submetidos a um teste de sanidade visando verificar a presença do patógeno. O fungo F. oxysporum f. sp. basilici foi detectado em quatro dos seis lotes e os isolados obtidos das sementes contaminadas mostraram similar sintomatologia e um idêntico perfil de virulência aos verificados em campo e casa de vegetação, sugerindo que as sementes

  13. Clarification on Host Range of Didymella pinodes the Causal Agent of Pea Ascochyta Blight.

    Science.gov (United States)

    Barilli, Eleonora; Cobos, Maria José; Rubiales, Diego

    2016-01-01

    Didymella pinodes is the principal causal agent of ascochyta blight, one of the most important fungal diseases of pea (Pisum sativum) worldwide. Understanding its host specificity has crucial implications in epidemiology and management; however, this has not been clearly delineated yet. In this study we attempt to clarify the host range of D. pinodes and to compare it with that of other close Didymella spp. D. pinodes was very virulent on pea accessions, although differences in virulence were identified among isolates. On the contrary, studied isolates of D. fabae, D. rabiei, and D. lentil showed a reduced ability to infect pea not causing macroscopically visible symptoms on any of the pea accessions tested. D. pinodes isolates were also infective to some extend on almost all species tested including species such as Hedysarum coronarium, Lathyrus sativus, Lupinus albus, Medicago spp., Trifolium spp., Trigonella foenum-graecum, and Vicia articulata which were not mentioned before as hosts of D. pinodes. On the contrary, D. lentil and D. rabiei were more specific, infecting only lentil and chickpea, respectively. D. fabae was intermediate, infecting mainly faba bean, but also slightly other species such as Glycine max, Phaseolus vulgaris, Trifolium spp., Vicia sativa, and V. articulata. DNA sequence analysis of the nuclear ribosomal internal transcribed spacer region (ITS) was performed to confirm identity of the isolates studies and to determine phylogenetic relationship among the Didymella species, revealing the presence of two clearly distinct clades. Clade one was represented by two supported subclusters including D. fabae isolates as well as D. rabiei with D. lentil isolates. Clade two was the largest and included all the D. pinodes isolates as well as Phoma medicaginis var. pinodella. Genetic distance between D. pinodes and the other Didymella spp. isolates was not correlated with overall differences in pathogenicity. Based on evidences presented here, D

  14. Overwintering form of the causal agent of shot hole disease in Khorasan Razavi, Iran.

    Science.gov (United States)

    Panjehkeh, N; Yosefi, A

    2011-01-01

    Shot hole disease of stone fruit trees caused by some plant pathogenic fungi is a major constraint to stone fruit production worldwide where the trees are grown. Identification of the causal agents of the disease and their overwintering forms in stone fruit trees of Khorasan Razavi was necessary for disease management programs. Buds, twigs, fallen leaves and fruits were collected from the infected peach, apricot, nectarine and almond trees in winter 2007. The samples were superficially disinfested in 1% sodium hypochlorite for 2-3 min and then in 70% ethanol for 45 sec. Two to three fragments of 4x4 mm from each tissue were separately cultured on 2% water agar and potato dextrose agar (PDA), and purified on PDA. Just a pathogenic fungal species, Wilsonomyces corpophilus was isolated from the infected buds and twigs. No microorganism was isolated from the fallen leaves and fruits collected from underneath of the infested stone fruit trees. Pathogenicity of the fungus was examined on detached shoots of current year of four varieties of stone fruit trees. Fungal discs were placed under the bark of the bud base. Control shoots were similarly treated with sterile PDA discs. Inoculated shoots were placed in a humid growth chamber at 25 degrees C. Fungal hyphae appeared at 30 days post inoculation. Control shoots were asymptomatic. Pathogenicity intensities or lesion lengths were significantly different among the four varieties tested. A completely randomised design with five replicates was employed to measure the number of spores in infested buds and twigs of each variety of stone fruit tree. The samples were sliced and placed into a glass tube of centrifuge containing 3 ml of sterile distilled water. They were mixed on a vortex mixer for 30-40 min and centrifuged at 3000 rpm for 5 min. Pelleted material from each sample was suspended in 500 microl of sterile distilled water and the spores were counted using a hemocytometre. Results revealed that the fungus overwinters

  15. Clarification on host range of Didymella pinodes the causal agent of pea ascochyta blight

    Directory of Open Access Journals (Sweden)

    Eleonora eBarilli

    2016-05-01

    Full Text Available Didymella pinodes is the principal causal agent of ascochyta blight, one of the most important fungal diseases of pea (Pisum sativum worldwide. Understanding its host specificity has crucial implications in epidemiology and management; however, this has not been clearly delineated yet. In this study we attempt to clarify the host range of D. pinodes and to compare it with that of other close Didymella spp. D. pinodes was very virulent on pea accessions, although differences in virulence were identified among isolates. On the contrary, studied isolates D. fabae, D. rabiei and D. lentil showed a reduced ability to infect pea not causing macroscopically visible symptoms on any of the pea accessions tested.D. pinodes isolates were also infective to some extend on almost all species tested including species such as Hedysarum coronarium, Lathyrus sativus, Lupinus albus, Medicago spp., Trifolium spp., Trigonella foenum-graecum and Vicia articulata which were not mentioned before as hosts of D. pinodes. On the contrary, D. lentil and D. rabiei were more specific, infecting only lentil and chickpea, respectively. D. fabae was intermediate, infecting mainly faba bean, but also slightly other species such as Glycine max, Phaseolus vulgaris, Trifolium spp., Vicia sativa and V. articulata.DNA sequence analysis of the nuclear ribosomal internal transcribed spacer region (ITS was performed to confirm identity of the isolates studies and to determine phylogenetic relationship among the Didymella species, revealing the presence of two clearly distinct clades. Clade one was represented by two supported subclusters including D. fabae isolates as well as D. rabiei with D. lentil isolates. Clade two was the largest and included all the D. pinodes isolates as well as Phoma medicaginis var. pinodella. Genetic distance between D. pinodes and the other Didymella spp. isolates was not correlated with overall differences in pathogenicity. Based on evidences presented here

  16. ANTAGONISTIC EFFECT OF FOUR FUNGAL ISOLATES TO GANODERMA BONINENSE, THE CAUSAL AGENT OF BASAL STEM ROT OF OIL PALM

    Directory of Open Access Journals (Sweden)

    OKKY SETYAWATI DHARMAPUTRA

    1990-01-01

    Full Text Available Four fungal isolates from soils obtained from three sites of the oil palm plantations in North Sumatra were found antagonistic to Ganoderma boninense, the causal agent of basal stem rot of oil palm. Penicillium citrinum inhibited the growth of the pathogen and formed a zone of inhibition on the agar media. Trichoderma harzianum BIO - 1 as well as BIO - 2 and T. viride not only repressed the growth of the pathogen but also caused lysis of the hyphae, and the colony was totally overgrown by the antagonists.

  17. Monitoring of Soft Fruit Mother Plantings Aimed at Control of Phytophthora fragariae, Causal Agent of Root Rot

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    Slobodan Milenković

    2006-12-01

    Full Text Available Phytophthora fragariae was first detected in the Republic of Serbia in 2002, and it has been included in A2 quarantine list of damaging organisms since 2003. The project titled ‘Monitoring of soft fruit mother plantings aimed at the control of Phytophthora fragariae, causal agent of root rot’ was realized over 2004 – 2005 aiming at determination of population rate of the pathogen and the control of raspberry planting material. Over that period, the total 388 samples were tested. Collected samples were analyzed by PCR. The presence of Phytophthora fragariae was detected in 156 samples.

  18. Species-specific detection and identification of fusarium species complex, the causal agent of sugarcane pokkah boeng in China.

    Directory of Open Access Journals (Sweden)

    Zhenyue Lin

    Full Text Available BACKGROUND: Pokkah boeng disease caused by the Fusarium species complex results in significant yield losses in sugarcane. Thus, the rapid and accurate detection and identification of the pathogen is urgently required to manage and prevent the spreading of sugarcane pokkah boeng. METHODS: A total of 101 isolates were recovered from the pokkah boeng samples collected from five major sugarcane production areas in China throughout 2012 and 2013. The causal pathogen was identified by morphological observation, pathogenicity test, and phylogenetic analysis based on the fungus-conserved rDNA-ITS. Species-specific TaqMan real-time PCR and conventional PCR methods were developed for rapid and accurate detection of the causal agent of sugarcane pokkah boeng. The specificity and sensitivity of PCR assay were also evaluated on a total of 84 isolates of Fusarium from China and several isolates from other fungal pathogens of Sporisorium scitamineum and Phoma sp. and sugarcane endophyte of Acremonium sp. RESULT: Two Fusarium species (F. verticillioides and F. proliferatum that caused sugarcane pokahh boeng were identified by morphological observation, pathogenicity test, and phylogenetic analysis. Species-specific TaqMan PCR and conventional PCR were designed and optimized to target their rDNA-ITS regions. The sensitivity of the TaqMan PCR was approximately 10 pg of fungal DNA input, which was 1,000-fold over conventional PCR, and successfully detected pokkah boeng in the field-grown sugarcane. CONCLUSIONS/SIGNIFICANCE: This study was the first to identify two species, F. verticillioides and F. proliferatum, that were causal pathogens of sugarcane pokkah boeng in China. It also described the development of a species-specific PCR assay to detect and confirm these pathogens in sugarcane plants from mainland China. This method will be very useful for a broad range of research endeavors as well as the regulatory response and management of sugarcane pokkah boeng.

  19. Estabilidade da polpa de morango atomizada utilizando diferentes agentes carreadores

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    Maria Isabel Sousa Oliveira

    2013-12-01

    Full Text Available Este trabalho teve por objetivo avaliar o efeito de diferentes agentes carreadores (Maltodextrina 5DE, Maltodextrina 10DE, Goma arábica e Capsul® nas características físico-químicas (umidade, densidade, solubilidade, teor de antocianinas e atividade antioxidante da polpa de morango desidratada por atomização e armazenada à temperatura ambiente por 90 dias. A utilização dos diferentes agentes carreadores resultou em pós com valores de densidade aparente entre 0,40 e 0,52 g/cm³ e umidade menor do que 2,5%. Todas as amostras foram altamente solúveis, mas os pós obtidos com a Maltodextrina 5DE e com a Goma arábica apresentaram menor higroscopicidade. As isotermas de sorção obtidas foram do tipo III e o modelo de GAB foi o que melhor se ajustou aos dados experimentais. A amostra produzida com goma arábica apresentou a maior concentração de antocianinas e, consequentemente, maior valor de atividade antioxidante, tanto imediatamente após a secagem como ao longo de 90 dias de armazenamento. Os resultados obtidos indicaram que a goma arábica foi o agente carreador mais adequado para a produção de polpa de morango em pó.

  20. Actividad antifúngica del quitosano y aceites esenciales sobre rhizopus stolonifer (ehrenb.:fr.) vuill., agente causal de la pudrición blanda del tomate

    OpenAIRE

    Alejandra María Alvarado Hernández; Laura Leticia Barrera Necha; Ana Niurka Hernández Lauzardo; Miguel Gerardo Velázquez del Valle

    2012-01-01

    Título en ingles: Antifungal activity of chitosan and essential oils on Rhizopus stolonifer (Ehrenb.:Fr.) Vuill causal agent of soft rot of tomato ResumenRhizopus stolonifer es el agente causal de la pudrición blanda, enfermedad poscosecha que ocasiona pérdidas económicas importantes. Se han empleado fungicidas sintéticos como el dicloran para controlar a este microorganismo, sin embargo, se ha demostrado que los fungicidas representan un riesgo para el ambiente y la salud humana. Actualmente...

  1. Amebae and ciliated protozoa as causal agents of waterborne zoonotic disease.

    Science.gov (United States)

    Schuster, Frederick L; Visvesvara, Govinda S

    2004-12-01

    The roles free-living amebae and the parasitic protozoa Entamoeba histolytica and Balantidium coli play as agents of waterborne zoonotic diseases are examined. The free-living soil and water amebae Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris are recognized etiologic agents of mostly fatal amebic encephalitides in humans and other animals, with immunocompromised and immunocompetent hosts among the victims. Acanthamoeba spp. are also agents of amebic keratitis. Infection is through the respiratory tract, breaks in the skin, or by uptake of water into the nostrils, with spread to the central nervous system. E. histolytica and B. coli are parasitic protozoa that cause amebic dysentery and balantidiasis, respectively. Both intestinal infections are spread via a fecal-oral route, with cysts as the infective stage. Although the amebic encephalitides can be acquired by contact with water, they are not, strictly speaking, waterborne diseases and are not transmitted to humans from animals. Non-human primates and swine are reservoirs for E. histolytica and B. coli, and the diseases they cause are acquired from cysts, usually in sewage-contaminated water. Amebic dysentery and balantidiasis are examples of zoonotic waterborne infections, though human-to-human transmission can occur. The epidemiology of the diseases is examined, as are diagnostic procedures, anti-microbial interventions, and the influence of globalization, climate change, and technological advances on their spread. PMID:15567581

  2. Brown rot on nuts of Castanea sativa Mill: an emerging disease and its causal agent

    Directory of Open Access Journals (Sweden)

    Maresi G

    2013-07-01

    Full Text Available The quality and quantity of nut production are fundamental to the economic viability of chestnut cultivation, yet recent reports indicate that severe damage due to moulds represents a significant problem for growers. We carried out an investigation of the agents of chestnut rot and internal fruit damage in three orchards in Italy. Black and brown rot, as well as insect damage, were found in all the areas examined. Brown rot appeared to be the main cause of damage, affecting 8% to 49% and 2% to 24% of nuts collected from the ground and from burrs, respectively. With respect to morphology and DNA sequencing analyses, fungal isolates obtained from brown rot were homologous with Gnomoniopsis sp. obtained from Dryocosmus kuriphilus (Yasumatsu galls and with Gnomoniopsis castanea and Gnomoniopsis smithogilvyi described on chestnut in Italy and Australia, respectively. The same fungus was also isolated from the bark of one- and two-years-old healthy shoots at each site, supporting the endophytic behaviour of this rot agent. Brown rot symptoms on nuts associated with Gnomoniopsis sp. corresponded with those previously described by several authors and referred to as Phoma or Phomopsis endogena, suggesting a relationship between these fungi and Gnomoniopsis sp. It is to notice that the escalation of brown rot damage in Italy followed several periods of drought and probably the recent invasion of D. kuriphilus, both stress factors for chestnut trees.

  3. 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.

  4. Isolation and characterization of the mating type locus of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana

    NARCIS (Netherlands)

    Conde-Ferráez, L.; Waalwijk, C.; Canto-Canché, B.B.; Kema, G.H.J.; Crous, P.W.; James, A.C.; Abeln, E.C.A.

    2007-01-01

    Idiomorphs mat1-1 and mat1-2 from Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana, were isolated. Degenerate oligos were used to amplify the HMG box of the mat1-2 idiomorph from M. fijiensis, showing homology with the HMG box of Mycosphaerella graminicola. Using a D

  5. Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp)

    NARCIS (Netherlands)

    Garcia, S.A.L.; Lee, van der T.A.J.; Ferreira, C.F.; Lintel Hekkert, te B.; Zapater, M.F.; Goodwin, S.B.; Guzmán, M.; Kema, G.H.J.; Souza, M.T.

    2010-01-01

    ABSTRACT. We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Mus

  6. Variable Number of Tandem Repeat Markers in the Genome Sequence of Mycosphaerella Fijiensis, the Causal Agent of Black Leaf Streak Disease of Banana (Musa spp.)

    Science.gov (United States)

    Mycosphaerella fijiensis, the causal agent of banana leaf streak disease (commonly known as black Sigatoka), is the most devastating pathogen attacking bananas (Musa spp). Recently the whole genome sequence of M. fijiensis became available. This sequence was screened for the presence of Variable Num...

  7. Presencia de Blastocystis Hominis como agente causal de enfermedades gatrointestinales en la comuna 7 (Gaira del Distrito de Santa Marta

    Directory of Open Access Journals (Sweden)

    Sonja Liliana Lozano Socarras

    2013-10-01

    Full Text Available La Blastocystis hominis es un protozoo que causa cuadros diarreicos. Es altamente prevalente en poblaciones que no cuentan con servicios adecuados de higiene, alcantarillado y salud pública. La infección con Blastocystis hominis frecuentemente concomita con otros enteropatógenos de reconocida patogenicidad, además se ha reportado como parásito oportunista en pacientes con VIII SIDA. El objetivo del presente estudio es determinar la presencia de Blastocystis hominis en pacientes de consulta externa con síntomas asociados a enfermedades gastrointestinales, en la comuna 7 del distrito de Santa Marta, Colombia, durante el mes de Enero a Diciembre de 2004. El método de diagnóstico utilizado fue examen coproparasitológico seriado y el número de pacientes analiza-dos fue de 291. Los resultados muestran una alta presencia de Blastocystis hominken pacientes con enfermedad diarreica residentes en Gaira. Un alto porcentaje de la población parasitada (62,6% presento como único agente causal de la enfermedad diarreica al Blastocystis hominis lo que sugiere la presencia de otras enfermedades que pueden involucrar un compromiso inmunológico, el efecto será una respuesta inmune débil contra el parásito.

  8. Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis

    Directory of Open Access Journals (Sweden)

    Abdjad Asih Nawangsih

    2011-04-01

    Full Text Available Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis. X. oryzae pv. oryzae (Xoo causes bacterial leaf blight (BLB of rice (Oryza sativa L., a major disease that constrains production of the staple crop in many countries of the world. Identification of X. oryzae pv. oryzae (Xoo was conducted based on the disease symptoms, pathogenicity, morphological, physiological, and genetic characteristics of bacterial cultures isolated from the infected plants. Fifty bacterial isolates predicted as Xoo have been successfully isolated. They are aerobic, rod shaped, and Gram negative bacteria. The isolates were evaluated for their hypersensitivity in tobacco and pathogenicity in rice plant. Fifty isolates induced hypersensitive reaction in tobacco and showed pathogenicity symptom in rice in different length. Based on physiological test, hypersensitivity and pathogenicity reactions, three bacterial isolates strongly predicted as Xoo, i.e. STG21, STG42, and STG46, were non indole formation, non pigment fluorescent, hydrolyzed casein, catalase activity positive, but negative oxidase. Partial sequencing of 16S rRNA genes of STG21 and STG42 showed 80% and 82% homology with X. oryzae, respectively, while STG46 showed 84% homology with X. campestris. Mini-Tn5 transposon mutagenesis of STG21 generated one of the mutants (M5 lossed it’s ability to induce hypersensitive reaction in tobacco plant and deficient in pathogenicity on rice. The lesion length of rice leaf caused by the mutant M5 decreased up to 80%.

  9. Podredumbres basales de Gypsophila paniculata (Caryophyllaceae: Agentes causales y su patogenicidad potencial sobre Dianthus caryophyllus (Caryophyllaceae Basal rots of Gypsophila paniculata (Caryophyllaceae: Causal agents and its potential pathogenicity on Dianthus caryophyllus (Caryophyllaceae

    Directory of Open Access Journals (Sweden)

    Silvia María Wolcan

    Full Text Available Los objetivos del trabajo fueron identificar a los agentes causales de las podredumbres basales de Gypsophila paniculata en la Argentina y probar su posible patogenicidad sobre Dianthus caryophyllus . A partir de plantas con síntomas de «podredumbre de la corona» (la más importante se aislaron en orden decreciente: Fusarium solani , F. oxysporum , Phytophthora nicotianae , Rhizoctonia solani , F. graminearum , F. verticillioides, F. equiseti y Pythium sp. y de plantas con «podredumbre basal del tallo» F. graminearum , F. oxysporum y F. solani . Con distintas cepas de cada hongo se hicieron pruebas de patogenicidad mediante la infestación del suelo y el depósito de inóculo en heridas producidas en los tallos. En la «podredumbre de la corona» fueron patógenos P. nicotianae causando decaimiento rápido de la parte aérea y podredumbre blanda de la corona y R. solani causando una pudrición más lenta y tejidos desintegrados. F. graminearum fue el patógeno de la «podredumbre basal del tallo» de gipsofila, que se describe por primera vez en este hospedante , comprobando que el hongo penetra sólo por heridas del tallo. En condiciones de inoculación se confirmó que algunas cepas de R. solani y de F. graminearum aisladas de gipsofila pueden ser patógenas de clavel mientras que sólo algunas de P. nicotianae resultaron patógenas débiles.The aims of the paper were to determine the causal agents of basal rots of Gypsophila paniculata in Argentina, and to evaluate its possible pathogenicity on Dianthus caryophyllus. Fusarium solani, F. oxysporum , Phytophthora nicotianae , Rhizoctonia solani , F. graminearum , F. verticilloides, F. equiseti and Pythium sp. were isolated in decreasing order from plants with symptoms of «crown rot» (the major basal rot. F. graminearum , F. oxysporum and F. solani were isolated from plants with «basal stem rot». Inoculations of gypsophila were performed by soil infestation and by placing inoculum on

  10. Exploring Mechanisms of Resistance to Respiratory Inhibitors in Field Strains of Botrytis cinerea, the Causal Agent of Gray Mold ▿ †

    OpenAIRE

    Leroux, Pierre; Gredt, Michel; Leroch, Michaela; Walker, Anne-Sophie

    2010-01-01

    Respiratory inhibitors are among the fungicides most widely used for disease control on crops. Most are strobilurins and carboxamides, inhibiting the cytochrome b of mitochondrial complex III and the succinate dehydrogenase of mitochondrial complex II, respectively. A few years after the approval of these inhibitors for use on grapevines, field isolates of Botrytis cinerea, the causal agent of gray mold, resistant to one or both of these classes of fungicide were recovered in France and Germa...

  11. Evidence Suggesting that Fasciola gigantica Might be the Most Prevalent Causal Agent of Fascioliasis in Northern Iran

    Directory of Open Access Journals (Sweden)

    K Ashrafi

    2004-10-01

    out and all trematodes recovered at necropsy, 8 weeks post-exposure, appeared to be F. gigantica based on morphology. The high temperature, moisture and rainfall during the year, especially in Bandar-Anzali, support the establishment and transmission of the disease in the zone. Although the species involved in human infections in endemic areas of Gilan has been usually referred to as F. hepatica, the results of this study as well as some interesting epidemiological evidences related to the disease, support that Fasciola gigantica might be the main causal agent of fascioliasis in this important endemic zone.

  12. Identificación del agente causal de la pudrición blanca en Morelos, México

    Directory of Open Access Journals (Sweden)

    Ernesto Hernández Mendieta

    2013-12-01

    Full Text Available Título en ingles: Identification of the white rot agent in Morelos, MexicoTítulo corto: Agente causal de la pudrición blanca en Morelos, MéxicoResumen: Cepas aisladas de Trametes versicolor (L.:Fr. Pilát causando pudrición blanca en especies arbóreas de amate amarillo (Ficus petiolaris, cirián o cuatecomate (Crescentia alata, guayaba (Psidium guajava y sauce colorado (Salix humboltiana en los municipios de Ayala, Cuautla, Cuernavaca, Jojutla, Tepalcingo, Tlaltizapán, Tlaquiltenango y Zacatepec de Hidalgo en el estado de Morelos, México se desarrollaron en medio de cultivo agua-agar enriquecido con 2,4-D amina en concentraciones de 0, 50, 100, 150, 250, 500, 1000, 2000, 3000, 4000 y 5000 ppm, con el objetivo de conocer su desarrollo en esta sal. Los mejores resultados se obtuvieron en un intervalo de 50 a 1000 ppm con un óptimo de 500 a 1000 ppm.L, las concentraciones de 2000 a 5000 ppm inhiben el desarrollo del hongo. Se confirma que las cepas aisladas de T. versicolor pueden emplearse como herramienta potencial de biorremediación de aguas contaminadas por ácido 2,4-D que es empleado como herbicida para el control de malezas de hoja ancha en cultivos de maíz, arroz, caña de azúcar y sorgo en la región de estudio.Palabras clave: Trametes versicolor, identificación, ácido 2,4-diclorofenoxiacetico, 2,4-D.Abstract: Trametes versicolor (L.: Fr Pilát was identified causing white rot of hardwood tree species of amate amarillo (Ficus petiolaris, cuatecomate or cirián (Crescentia alata, guayava (Psidium guajava and sauce colorado (Salix humboltiana in municipalities of Ayala, Cuautla, Cuernavaca, Jojutla Tepalcingo Tlaltizapan, Tlaquiltenango and Zacatepec de Hidalgo in the state of Morelos, Mexico. Collected strains were grown in water-agar culture medium with 2,4-D amine at concentrations of 0, 50, 100, 150, 250, 500, 1000, 2000, 3000, 4000 and 5000 ppm with the aim of know their growth in this salt. The best results were found

  13. 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…

  14. Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

    OpenAIRE

    PENICHE-LARA, Gaspar; Dzul-Rosado, Karla; PÉREZ-OSORIO, Carlos; Zavala-Castro, Jorge

    2015-01-01

    Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chai...

  15. Characterization of an RTX-Like Toxin and an Alpha-2-Macroglobulin in Pantoea stewartii subsp. stewartii, Causal Agent of Stewart's Wilt of Sweet Corn

    OpenAIRE

    Williams, Kayla Marie

    2014-01-01

    Pantoea stewartii subsp. stewartii DC283, the causal agent of Stewart's wilt, is an important bacterial pathogen of sweet corn. P. stewartii colonizes the apoplastic space and xylem tissue, resulting in characteristic water-soaked (WS) lesions and wilting. A gene encoding a putative RTX-like toxin, rtx2, has been identified in P. stewartii. RTX toxins belong to the pore-forming toxin family and have lytic properties in animal systems. Little is known about the role of RTX toxins in plant path...

  16. Actividad antifúngica del quitosano y aceites esenciales sobre Rhizopus stolonifer (Ehrenb.:Fr.) Vuill., agente causal de la pudrición blanda del tomate

    OpenAIRE

    Alejandra María Alvarado Hernández; Laura Leticia Barrera Necha; Ana Niurka Hernández Lauzardo; Miguel Gerardo Velázquez del Valle

    2011-01-01

    Rhizopus stolonifer es el agente causal de la pudrición blanda, enfermedad poscosecha que ocasiona pérdidas económicas importantes. Se han empleado fungicidas sintéticos como el dicloran para controlar a este microorganismo, sin embargo, se ha demostrado que los fungicidas representan un riesgo para el ambiente y la salud humana. Actualmente se buscan alternativas naturales para el control de las pudriciones poscosecha. Se evaluó in vitro e in situ el efecto antifúngico del quitosano y de los...

  17. Species-Specific Detection and Identification of Fusarium Species Complex, the Causal Agent of Sugarcane Pokkah Boeng in China

    OpenAIRE

    Zhenyue Lin; Shiqiang Xu; Youxiong Que; Jihua Wang; Comstock, Jack C.; Jinjin Wei; McCord, Per H.; Baoshan Chen; Rukai Chen; Muqing Zhang

    2014-01-01

    BACKGROUND: Pokkah boeng disease caused by the Fusarium species complex results in significant yield losses in sugarcane. Thus, the rapid and accurate detection and identification of the pathogen is urgently required to manage and prevent the spreading of sugarcane pokkah boeng. METHODS: A total of 101 isolates were recovered from the pokkah boeng samples collected from five major sugarcane production areas in China throughout 2012 and 2013. The causal pathogen was identified by morphological...

  18. A novel fungal hyperparasite of Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe rust.

    Directory of Open Access Journals (Sweden)

    Gangming Zhan

    Full Text Available Puccinia striiformis f. sp. tritici (Pst, the causal fungus of wheat stripe rust, was previously reported to be infected by Lecanicillium lecanii, Microdochium nivale and Typhula idahoensis. Here, we report a novel hyperparasite on Pst. This hyperparasitic fungus was identified as Cladosporium cladosporioides (Fresen. GA de Vries based on morphological characteristics observed by light and scanning electron microscopy together with molecular data. The hyperparasite reduced the production and viability of urediniospores and, therefore, could potentially be used for biological control of wheat stripe rust.

  19. Efecto depresivo de los agentes causales de las pudriciones secas en plantas producidas in vitro de malanga (Xanthosoma sagittifolium

    Directory of Open Access Journals (Sweden)

    Ernesto Espinosa Cuellar

    2012-06-01

    Full Text Available Título en ingles: Depressive effect of the causative agents of dry rot in plants grown in vitro from malanga (Xanthosoma sagittifolium Resumen Se determinó el efecto depresivo sobre plantas de malanga producidas in vitro del cultivar “Amarilla Especial”, de los hongos Fusarium oxysporum Schlecht, Rhizoctonia solani  Kühn y Sclerotium rolfsii Sacc  aislados de plantas infectadas que presentaban síntomas de escaso desarrollo, clorosis, necrosis foliar y pudrición de las raíces. Los tratamientos consistieron en el aislamiento de los tres hongos por separado, la mezcla de los tres hongos y un control sin inocular. Se plantaron plantas previamente aclimatizadas en cámaras que tenían una dimensión de 0,90 x 0,90 x 0,90 m, en bloque completamente al azar con cuatro réplicas. Se inocularon 100 plantas por cada tratamiento y como control se dejaron igual número de plantas sin inocular, se evaluó en cada caso la altura de la planta, el número de raíces por planta y el número de raíces enfermas, y posteriormente se determinó el peso fresco y seco de las raíces y el follaje. Se cosechó a los 10 meses después de la plantación y se evaluaron algunos componentes del rendimiento, como el número de cormos y cormelos y su peso fresco, al igual que la intensidad de los daños en el momento de la cosecha. Los resultados mostraron que los hongos fitopatógenos Fusarium oxysporum Schlecht, Rhizoctonia solani  Kühn y Sclerotium rolfsii Sacc asociados a las pudriciones secas, ocasionaron un efecto depresivo en las plantas de malanga producidas in vitro cultivadas en cámaras. La mezcla de estos tres hongos resultó muy agresiva, lo que provocó en las plantas una disminución en la altura, el peso fresco del follaje y en el número de raíces, cormos y cormelos. Palabras clave: malanga, pudriciones secas, hongos, Abstract Depressive effect was determined on plants produced in vitro taro cultivar 'Amarilla Especial', fungi Fusarium

  20. 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 develop discursive institutional analytical frameworks and something that comes close to the formulation of hypothesis on the effects of European Union (EU) policies and institutions on domestic change. Even if these efforts so far do not necessarily amount to substantive theories or claims of causality......, 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 study...

  1. Preservação de urediniósporos de Puccinia melanocephala, agente causal de ferrugem em cana-de-açúcar Preservation of uredospores of Puccinia melanocephala, the causal agent of sugarcane rust

    Directory of Open Access Journals (Sweden)

    Ely Oliveira Garcia

    2007-06-01

    Full Text Available A sazonalidade na manifestação da ferrugem da cana dificulta a obtenção de esporos em quantidades adequadas para inoculações em qualquer época do ano, restringindo os trabalhos envolvendo o patógeno aos meses nos quais a doença esta presente no campo. O trabalho visou desenvolver uma metodologia para preservar os esporos por períodos prolongados, mantendo sua viabilidade e infectividade. Esporos foram coletados a partir de folhas naturalmente infectadas, com bomba de vácuo. Parte dos esporos foi desidratada por liofilização ou em sílica gel e outra parte não passou por desidratação. Armazenaram-se estes esporos em diferentes temperaturas (temp. ambiente, 5ºC, -20 ºC, -80ºC. Periodicamente, a viabilidade dos esporos foi avaliada por meio de plaqueamento em ágar-água. Após o quarto mês, foi também avaliada a infectividade dos esporos armazenados por meio de inoculações na variedade suscetível SP70-1143, seguida da avaliação da área foliar atacada. Os esporos armazenados à temperatura ambiente e a 5ºC, independentemente da desidratação, permaneceram viáveis por períodos máximos de 1 mês e 2 meses, respectivamente. Os melhores tratamentos consistiram na desidratação em sílica gel, seguida pelo armazenamento à -20ºC e -80ºC. Mesmo após um ano de armazenamento nestas condições, os esporos provocaram ferrugem nas plantas inoculadas, em níveis de severidade adequados para um teste de discriminação de reações à ferrugem.The seasonality in the appearance of sugarcane rust makes it difficult to obtain in any season of year, adequate quantities uredospores for artificial inoculations in a breeding program. This research aimed to develop a long-term storage methodology to preserve uredospores of Puccicinia melanocephala to keep their viability and infectivity. Uredospores were collect using a vacuum pump from naturally rusted leaves. Part of these uredospores was dehydrated in silica gel or lyophilized

  2. Murcha do manjericão (Ocimum basilicum) no Brasil: agente causal, círculo de plantas hospedeiras e transmissão via semente Sweet basil (Ocimum basilicum) wilt in Brazil: causal agent, host range and seed transmission

    OpenAIRE

    Ailton Reis; Bruno Eduardo Cardoso Miranda; Leonardo Silva Boiteux; Gilmar Paulo Henz

    2007-01-01

    O manjericão (Ocimum basilicum L.) é uma hortaliça da família Lamiaceae, utilizada na culinária ou como matéria prima para a indústria de fármacos e óleos essenciais. Amostras de plantas de manjericão apresentando sintomas de murcha, seca de hastes e podridão de colo foram coletadas na área rural de Brazlândia (DF) durante a estação chuvosa de 2005. Outras duas amostras foram coletadas em plantas cultivadas em campo aberto e casas de vegetação na região de Ponte Alta (DF). Isolados de um fung...

  3. Isolation and identification of Avibacterium paragallinarum, the causal agent of infectious coryza (IC) from layer chickens in Bangladesh

    OpenAIRE

    Akter, S.; Ali, M.; Das, P.M; Hossain, M. M.

    2013-01-01

    This study was carried out for the isolation and identification of Avibacterium paragallinarum, the etiological agent of infectious coryza (IC). Pathological changes were also investigated that occurred in organs in layer chickens obtained from some selected areas of Bangladesh. A nasal swabs (n=30) from dead chickens and four swabs from live chickens were collected aseptically. The organisms from swabs were cultured in different media, stained, and followed by sugar fermentation and biochemi...

  4. Glucanases and chitinases as causal agents in the protection of Acacia extrafloral nectar from infestation by phytopathogens.

    Science.gov (United States)

    González-Teuber, Marcia; Pozo, María J; Muck, Alexander; Svatos, Ales; Adame-Alvarez, Rosa M; Heil, Martin

    2010-03-01

    Nectars are rich in primary metabolites and attract mutualistic animals, which serve as pollinators or as an indirect defense against herbivores. Their chemical composition makes nectars prone to microbial infestation. As protective strategy, floral nectar of ornamental tobacco (Nicotiana langsdorffii x Nicotiana sanderae) contains "nectarins," proteins producing reactive oxygen species such as hydrogen peroxide. By contrast, pathogenesis-related (PR) proteins were detected in Acacia extrafloral nectar (EFN), which is secreted in the context of defensive ant-plant mutualisms. We investigated whether these PR proteins protect EFN from phytopathogens. Five sympatric species (Acacia cornigera, A. hindsii, A. collinsii, A. farnesiana, and Prosopis juliflora) were compared that differ in their ant-plant mutualism. EFN of myrmecophytes, which are obligate ant-plants that secrete EFN constitutively to nourish specialized ant inhabitants, significantly inhibited the growth of four out of six tested phytopathogenic microorganisms. By contrast, EFN of nonmyrmecophytes, which is secreted only transiently in response to herbivory, did not exhibit a detectable inhibitory activity. Combining two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis with nanoflow liquid chromatography-tandem mass spectrometry analysis confirmed that PR proteins represented over 90% of all proteins in myrmecophyte EFN. The inhibition of microbial growth was exerted by the protein fraction, but not the small metabolites of this EFN, and disappeared when nectar was heated. In-gel assays demonstrated the activity of acidic and basic chitinases in all EFNs, whereas glucanases were detected only in EFN of myrmecophytes. Our results demonstrate that PR proteins causally underlie the protection of Acacia EFN from microorganisms and that acidic and basic glucanases likely represent the most important prerequisite in this defensive function. PMID:20023149

  5. Causal universe

    CERN Document Server

    Ellis, George FR; Pabjan, Tadeusz

    2013-01-01

    Written by philosophers, cosmologists, and physicists, this collection of essays deals with causality, which is a core issue for both science and philosophy. Readers will learn about different types of causality in complex systems and about new perspectives on this issue based on physical and cosmological considerations. In addition, the book includes essays pertaining to the problem of causality in ancient Greek philosophy, and to the problem of God's relation to the causal structures of nature viewed in the light of contemporary physics and cosmology.

  6. Diversity of endophytic fungal community of cacao (Theobroma cacao L. and biological control of Crinipellis perniciosa, causal agent of Witches' Broom Disease

    Directory of Open Access Journals (Sweden)

    2005-02-01

    Full Text Available The basidiomycete fungus Crinipellis perniciosa (Stahel Singer is the causal agent of Witches' Broom Disease of Cacao (Theobroma cacao L. which is the main factor limiting cacao production in the Americas. Pod losses of up to 90% are experienced in affected areas as evidenced by the 50% drop in production in Bahia province, Brazil following the arrival of the C. perniciosa in the area in 1989. The disease has proven particularly difficult to control and many farmers in affected areas have given up cacao cultivation. In order to evaluate the potential of endophytes as a biological control agent of this phytopathogen, the endophytic fungal community of resistant and susceptible cacao plants as well as affected branches was studied between 2001 and 2002. The fungal community was identified by morphological traits and rDNA sequencing as belonging to the genera Acremonium, Blastomyces, Botryosphaeria, Cladosporium, Colletotrichum, Cordyceps, Diaporthe, Fusarium, Geotrichum, Gibberella, Gliocladium, Lasiodiplodia, Monilochoetes, Nectria, Pestalotiopsis, Phomopsis, Pleurotus, Pseudofusarium, Rhizopycnis, Syncephalastrum, Trichoderma, Verticillium and Xylaria. These fungi were evaluated both in vitro and in vivo by their ability to inhibit C. perniciosa. Among these, some were identified as potential antagonists, but only one fungus (Gliocladium catenulatum reduced the incidence of Witches' Broom Disease in cacao seedlings to 70%.

  7. Effect of Two Biological Formulations Based on Bacillus subtilis and Pseudomonas fluorescens on Control of Didymella applanata, the Causal Agent of Red Raspberry Cane Spur Blight

    Directory of Open Access Journals (Sweden)

    Margarita Shternshis

    2016-01-01

    Full Text Available In vitro and in vivo studies were conducted to estimate the efficacy of the two microbial formulations based on Bacillus subtilis Cohn. and Pseudomonas fluorescens Mig. on the fungus Didymella applanata (Niessl. Sacc., the causal agent of red raspberry (Rubus idaeus L. spur blight. In vitro, both bacteria reduced the growth of D. applanata. In inoculation experiments with raspberry canes in two cultivars with different susceptibility to D. applanata, these antagonistic bacteria suppressed fungal development by reducing the lesions area and the number of D. applanata fruiting bodies. Field trials of two biological formulations under natural conditions showed a significant suppression of the disease. B. subtilis and P. fluorescens included in the formulations revealed antagonistic activity towards D. applanata that depended on the red raspberry cultivar and weather conditions. In all cases, B. subtilis showed better results than P. fluorescens in biocontrol of the raspberry spur blight. This study demonstrated for the first time the ability of the biocontrol agents B. subtilis and P. fluorescens to suppress red raspberry cane spur blight, a serious worldwide disease.

  8. Causal and causally separable processes

    Science.gov (United States)

    Oreshkov, Ognyan; Giarmatzi, Christina

    2016-09-01

    The idea that events are equipped with a partial causal order is central to our understanding of physics in the tested regimes: given two pointlike events A and B, either A is in the causal past of B, B is in the causal past of A, or A and B are space-like separated. Operationally, the meaning of these order relations corresponds to constraints on the possible correlations between experiments performed in the vicinities of the respective events: if A is in the causal past of B, an experimenter at A could signal to an experimenter at B but not the other way around, while if A and B are space-like separated, no signaling is possible in either direction. In the context of a concrete physical theory, the correlations compatible with a given causal configuration may obey further constraints. For instance, space-like correlations in quantum mechanics arise from local measurements on joint quantum states, while time-like correlations are established via quantum channels. Similarly to other variables, however, the causal order of a set of events could be random, and little is understood about the constraints that causality implies in this case. A main difficulty concerns the fact that the order of events can now generally depend on the operations performed at the locations of these events, since, for instance, an operation at A could influence the order in which B and C occur in A’s future. So far, no formal theory of causality compatible with such dynamical causal order has been developed. Apart from being of fundamental interest in the context of inferring causal relations, such a theory is imperative for understanding recent suggestions that the causal order of events in quantum mechanics can be indefinite. Here, we develop such a theory in the general multipartite case. Starting from a background-independent definition of causality, we derive an iteratively formulated canonical decomposition of multipartite causal correlations. For a fixed number of settings and

  9. Comparison of antifungal activities of various essential oils on the Phytophthora drechsleri, the causal agent of fruit decay

    Directory of Open Access Journals (Sweden)

    Ali Mohammadi

    2015-10-01

    Full Text Available Background and Objectives: The efficacy of Mentha piperita L, Zataria multiflora Boiss and Thymus vulgaris L essential oils (EOs was evaluated for controlling the growth of Phytophthora drechsleri, the causative agent of damage to many crops that is consumed directly by humans.Materials and Methods: The EOs used in this study was purchased from Magnolia Co, Iran. The pour plate method in petri dishes containing Potato Dextrose Agar (PDA was used to evaluate the antifungal properties of EOs. The minimal inhibitory concentrations (MIC, minimum fungicidal concentration (MFC as well as mycelial growth inhibition (MGI were measured. The IC50 value (the concentration inhibited 50% of the mycelium growth was calculated by probit analysis.Results and Conclusion: The fungal growth was significantly reduced by increasing concentrations of tested EOs. The complete reduction was obtained with Shirazi thyme at all concentrations, whereas the complete reduction for peppermint and thyme was observed at 0.4% and 0.8% (v/v concentrations, respectively. Meanwhile, the minimum inhibition wasobserved when 0.1% peppermint (MGI values of 9.37% was used. The IC50, MIC and MFC values of Shirazi thyme was 0.053, 0.1% and 0.2%, respectively. Similarly, MIC and MFC values of peppermint and thyme were recorded 0.4% and 0.8%, respectively. The results obtained from this study may contribute to the development of new antifungal agents to protect the crops from this pathogenic fungus and many agricultural plant pathogens causing drastic crop losses.

  10. 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...

  11. Actividad antifúngica del quitosano y aceites esenciales sobre Rhizopus stolonifer (Ehrenb.:Fr. Vuill., agente causal de la pudrición blanda del tomate

    Directory of Open Access Journals (Sweden)

    Alejandra María Alvarado Hernández

    2012-06-01

    Full Text Available Título en ingles: Antifungal activity of chitosan and essential oils on Rhizopus stolonifer (Ehrenb.:Fr. Vuill causal agent of soft rot of tomato ResumenRhizopus stolonifer es el agente causal de la pudrición blanda, enfermedad poscosecha que ocasiona pérdidas económicas importantes. Se han empleado fungicidas sintéticos como el dicloran para controlar a este microorganismo, sin embargo, se ha demostrado que los fungicidas representan un riesgo para el ambiente y la salud humana. Actualmente se buscan alternativas naturales para el control de las pudriciones poscosecha. Se evaluó in vitro e in situ el efecto antifúngico del quitosano y de los aceites esenciales de canela (Cinnamomum zeylanicum, clavo (Syzygium aromaticum y tomillo (Thymus vulgaris y dicloran sobre Rhizopus stolonifer. Los tratamientos más efectivos para inhibir in vitro a Rhizopus stolonifer fueron obtenidos con quitosano a 10 mg mL-1, con los tres aceites esenciales probados a la concentración de  0,3 mg mL-1, las mezclas de quitosano a 10 mg mL-1 con los aceites a 0,3 mg mL-1 y el dicloran a 1 mg mL-1. Los experimentos in situ mostraron que el tratamiento individual con quitosano fue el mejor para reducir el porcentaje de infección de los frutos de tomate (Lycopersicon esculentum inoculados con Rhizopus stolonifer y que la mezcla de quitosano con aceites esenciales no mejora la actividad antifúngica. El quitosano y el dicloran fueron los mejores tratamientos para reducir la pérdida de peso de los frutos. Los tratamientos individuales con quitosano representan una alternativa natural para controlar la pudrición blanda en frutos de tomate. Palabras clave: quitosano; aceites esenciales; Rhizopus stolonifer; podredumbre blanda. AbstractRhizopus stolonifer is the causal agent of soft rot, postharvest disease that causes important economic losses. Synthetic fungicides such as dichloran have been used to control this microorganism; however, it has been shown that

  12. Suberin Regulates the Production of Cellulolytic Enzymes in Streptomyces scabiei, the Causal Agent of Potato Common Scab.

    Science.gov (United States)

    Padilla-Reynaud, Rebeca; Simao-Beaunoir, Anne-Marie; Lerat, Sylvain; Bernards, Mark A; Beaulieu, Carole

    2015-01-01

    Suberin, a major constituent of the potato periderm, is known to promote the production of thaxtomins, the key virulence factors of the common scab-causing agent Streptomyces scabiei. In the present study, we speculated that suberin affected the production of glycosyl hydrolases, such as cellulases, by S. scabiei, and demonstrated that suberin promoted glycosyl hydrolase activity when added to cellulose-, xylan-, or lichenin-containing media. Furthermore, secretome analyses revealed that the addition of suberin to a cellulose-containing medium increased the production of glycosyl hydrolases. For example, the production of 13 out of the 14 cellulases produced by S. scabiei in cellulose-containing medium was stimulated by the presence of suberin. In most cases, the transcription of the corresponding cellulase-encoding genes was also markedly increased when the bacterium was grown in the presence of suberin and cellulose. The level of a subtilase-like protease inhibitor was markedly decreased by the presence of suberin. We proposed a model for the onset of S. scabiei virulence mechanisms by both cellulose and suberin, the main degradation product of cellulose that acts as an inducer of thaxtomin biosynthetic genes, and suberin promoting the biosynthesis of secondary metabolites including thaxtomins. PMID:26330095

  13. A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight Revisión sobre el hongo Microcyclus ulei, agente causal del mal suramericano de la hoja del caucho

    Directory of Open Access Journals (Sweden)

    Ancízar Aristizábar Fabio

    2006-12-01

    Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.El hongo ascomycete Microcyclus ulei es el agente causal del SALB que es una de las enfermedades más importan­tes del árbol de caucho natural (Hevea brasiliensis en América Latina y ha sido responsable de numerosas pérdidas económicas. Este hongo ha presentado alta variabilidad fisiológica y se sugiere su alta adaptabilidad, dentro de los mecanismos asociados a su virulencia se ha descrito la tolerancia al HCN. Se han obtenido clones de Hevea resistentes mediante mejoramiento genético, sin embargo, aun no son bien conocidos los mecanismos asociados a ésta. Un mayor conocimiento de este patógeno permitirá el desarrollo de nuevas estrategias de control así como el mayor entendimiento de los mecanismos asociados a resistencia del hospedero. Palabras clave: Microcyclus ulei, SALB, Hevea brasiliensis.

  14. Pharmacokinetics of chlorogenic acid and corydaline in DA-9701, a new botanical gastroprokinetic agent, in rats.

    Science.gov (United States)

    Jung, Ji Won; Kim, Ju Myung; Jeong, Jin Seok; Son, Miwon; Lee, Hye Suk; Lee, Myung Gull; Kang, Hee Eun

    2014-07-01

    1.Few studies describing the pharmacokinetic properties of chlorogenic acid (CA) and corydaline (CRD) which are marker compounds of a new prokinetic botanical agent, DA-9701, have been reported. The aim of the present study is to evaluate the pharmacokinetic properties CA and CRD following intravenous and oral administration of pure CA (1-8 mg/kg) or CRD (1.1-4.5 mg/kg) and their equivalent dose of DA-9701 to rats. 2.  Dose-proportional AUC and dose-independent clearance (10.3-12.1 ml/min/kg) of CA were observed following its administration. Oral administration of CA as DA-9701 did not influence the oral pharmacokinetic parameters of CA. Incomplete absorption of CA, its decomposition in the gastrointestinal tract, and/or pre-systemic metabolism resulted in extremely low oral bioavailability (F) of CA (0.478-0.899%). 3.  CRD showed greater dose-normalized AUC in the higher dose group than that in lower dose group(s) after its administration due to saturation of its metabolism via decreased non-renal clearance (by 51.3%) and first-pass extraction. As a result, the F of CRD following 4.5 mg/kg oral CRD (21.1%) was considerably greater than those of the lower dose groups (9.10 and 13.8%). However, oral administration of CRD as DA-9701 showed linear pharmacokinetics as a result of increased AUC and F in lower-dose groups (by 182% and 78.5%, respectively) compared to those of pure CRD. The greater oral AUC of CRD for DA-9701 than for pure CRD could be due to decreased hepatic and/or GI first-pass extraction of CRD by other components in DA-9701.

  15. Biological Control of Sclerotinia sclerotiorum, Causal Agent of Sunflower Head and Stem Rot Disease, by Use of Soil borne Actinomycetes Isolates

    Directory of Open Access Journals (Sweden)

    F. Baniasadi

    2009-01-01

    Full Text Available Problem statement: High level of biosafety and non adverse effects on the environment of biocontrol strategies of pest management, are priorities of tomorrow's world agriculture. Actinomycetes are active biocontrol agents due to their antagonistic properties against wide range of plant pathogens particularly fungi. Fungal pathogens are liable for a big part of damages in agriculture economy. Approach: In the present research antifungal bioactivity of 50 isolates of Actinomycetes collected from soils of Kerman province of Iran was investigated against Sclerotinia sclerotiorum (Lib., the causal agent of stem rot in sunflower, through agar disc method and dual culture bioassays. The Streptomyces isolate No. 363 was propagated in submerged cultures and active crude was prepared upon which several biological characterizations performed. Greenhouse studies were achieved to confirm laboratory results. Results: Among the tested Streptomyces isolates, 10 isolates revealed antagonistic properties in dual culture procedure from which isolate No. 363 showed highest bioactivity. The active metabolite of Streptomyces isolate No. 363 was polar and well soluble in H2O. Using agar-disc method, progressive growth of the pathogen was highly reduced by the antagonist through exhibiting ability to constitute fungus-free zones of inhibitions. The results indicated that isolate No. 363 was a proper candidate for field biocontrol studies. Conclusion: Results may open a horizon for production of resistant transgenic plants having antifungal properties originated from biologically active Streptomyces spp. recognition and production of effective metabolite(s of Streptomyces spp. which was responsible for antifungal activities will be our commercial goal due to rich reserves of soil borne Actinomycetes in Iran.

  16. In vitro antibacterial effect of exotic plants essential oils on the honeybee pathogen Paenibacillus larvae, causal agent of American foul brood

    Energy Technology Data Exchange (ETDEWEB)

    Fuselli, S. R.; Garcia de la Rosa, S. B.; Eguaras, M. J.; Fritz, R.

    2010-07-01

    Chemical composition and antimicrobial activity of exotic plants essential oils to potentially control Paenibacillus larvae, the causal agent of American foul brood disease (AFB) were determined. AFB represents one of the main plagues that affect the colonies of honeybees Apis mellifera L. with high negative impact on beekeepers worldwide. Essential oils tested were niaouli (Melaleuca viridiflora) and tea tree (Melaleuca alternifolia) from Myrtaceae, and citronella grass (Cymbopogon nardus) and palmarosa (Cymbopogon martinii) from Gramineae. The components of the essential oils were identified by SPME-GC/MS analysis. The antimicrobial activity of the oils against P. larvae was determined by the broth micro dilution method. In vitro assays of M. viridiflora and C. nardus oils showed the inhibition of the bacterial strains at the lowest concentrations tested, with minimal inhibitory concentration (MIC) mean value about 320 mg L{sup -}1 for both oils, respectively. This property could be attributed to the kind and percentage of the components of the oils. Terpinen-4-ol (29.09%), {alpha}-pinene (21.63%) and limonene (17.4%) were predominant in M. viridiflora, while limonene (24.74%), citronelal (24.61%) and geraniol (15.79%) were the bulk of C. nardus. The use of these essential oils contributes to the screening of alternative natural compounds to control AFB in the apiaries; toxicological risks and other undesirable effects would be avoided as resistance factors, developed by the indiscriminate use of antibiotics. (Author) 40 refs.

  17. Fowl adenovirus Group I as a causal agent of inclusion body hepatitis/hydropericardium syndrome (IBH/HPS outbreak in brazilian broiler flocks

    Directory of Open Access Journals (Sweden)

    Elena Mettifogo

    2014-08-01

    Full Text Available Commercial broiler flocks from a farm located in the State of São Paulo, Brazil, presented diarrhea, depression, increased mortality and poor weight gain. Upon post-mortem examination, classical signs of Inclusion Body Hepatitis/Hydropericardium Syndrome (IBH/HPS were observed, including enlarged pale yellow-colored livers and straw-colored liquid in the pericardial sac. In addition, gross lesions were also observed in the kidneys, pancreas, thymus, intestines and gallbladder. Samples of these organs were analyzed by PCR for the detection of the hexon gene of the Fowl Adenovirus (FAdVs Group I. The results were positive for both flocks (A and B assayed by PCR. The macroscopic lesions associated with the detection of FAdV Group I by PCR in several of these affected organs allowed for the identification of IBH/HPS. In fact, this is the first report in Brazil of IBH/HPS in broilers, which identifies FAdVs group I as a causal agent of the disease. These findings may contribute to the worldwide epidemiology of the adenovirus-mediated hepatitis/hydropericardium syndrome.

  18. Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

    Directory of Open Access Journals (Sweden)

    Gaspar PENICHE-LARA

    2015-04-01

    Full Text Available Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.

  19. Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

    Science.gov (United States)

    PENICHE-LARA, Gaspar; DZUL-ROSADO, Karla; PÉREZ-OSORIO, Carlos; ZAVALA-CASTRO, Jorge

    2015-01-01

    Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán. PMID:25923891

  20. In vitro Antagonistic Mechanisms of Trichoderma spp. and Talaromyces flavus to Control Gaeumannomyces graminis var. tritici the Causal Agent of Wheat Take-all Disease

    Directory of Open Access Journals (Sweden)

    Seddighe Mohammadi

    2015-08-01

    Full Text Available Wheat take-all disease caused by Gaeumannomyces graminis var. tritici has recently been detected in different regions of Iran. With respect to biocontrol effect of Trichoderma spp. on many pathogenic fungi, seven isolates of Trichoderma and four isolates of Talaromyces were in vitro evaluated in terms of their biological control against the disease causal agent. In dual culture test the five isolates showed efficient competition for colonization against pathogenic fungus and the highest percentages of inhibition belonging to Talaromyces flavus 60 and Talaromyces flavus 136 were 59.52 and 57.61%, respectively. Microscopic investigations showed that in regions where antagonistic isolates and Gaeumannomyces graminis var. tritici coincide, hyphal contact, penetration and fragmentation of Gaeumannomyces graminis var. tritici were observed. Investigating the effect of volatile and non-volatile compounds at 10 ml concentration showed that the highest inhibition percentage on mycelium growth of the pathogen caused by T. harzianum (44.76% and T. longibrachiatum (52.38% respectively.

  1. Post-transcriptional silencing of the SGE1 gene induced by a dsRNA hairpin in Fusarium oxysporum f. sp cubense, the causal agent of Panama disease.

    Science.gov (United States)

    Fernandes, J S; Angelo, P C S; Cruz, J C; Santos, J M M; Sousa, N R; Silva, G F

    2016-01-01

    Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin. Thirteen transformants were selected based on different morphological characteristics, and sporulation in these transformants was significantly reduced by approximately 95% (P < 0.05) compared to that of the wild-type strain. The relative SGE1 expression levels in the transformant strains were reduced by 27 to 47% compared to those in the wild-type strain. A pathogenicity analysis revealed that the transformants were able to reach the rhizomes and pseudostems of the inoculated banana plants. However, the transformants induced initial disease symptoms in the banana plants approximately 10 days later than that by the wild-type Foc, and initial disease symptoms persisted even at 45 days after inoculation. These results indicate that the SGE1 gene is directly involved in the virulence of Foc. Therefore, SGE1 may be a potential candidate for host-induced gene silencing in banana plants. PMID:27173186

  2. Assimetria causal: um estudo

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    Túlio Aguiar

    2003-12-01

    Full Text Available Neste artigo, examinamos o aspecto assimétrico da relação causal, confrontando-o com o ponto de vista humiano e neo-humiano. Seguindo Hausman e Ehring, favorecemos uma abordagem situacional para a assimetria causal. Nós exploramos a análise do famoso exemplo do mastro (Flagpole, esclarecendo as conexões entre causação e explicação. Nosso diagnóstico geral é que a tradição neo-humiana supõe, equivocadamente, que as relações nômicas, com exceção de pequenos detalhes, exaurem as relações causais.This paper examines the asymmetrical aspect of causal relation, confronting it to Humean and Neo-Humean's view. Following Hausman and Ehring, we favor a situational approach to causal asymmetry. We explore the Hausman's analysis of flagpole's example, clearing the connexions between causation and explanation. Our general diagnosis is that the Neo-humean tradition wrongly supposes that nomic relations, with the exception of minor details, exhaust the causal relations.

  3. Epidemiological causality.

    Science.gov (United States)

    Morabia, Alfredo

    2005-01-01

    Epidemiological methods, which combine population thinking and group comparisons, can primarily identify causes of disease in populations. There is therefore a tension between our intuitive notion of a cause, which we want to be deterministic and invariant at the individual level, and the epidemiological notion of causes, which are invariant only at the population level. Epidemiologists have given heretofore a pragmatic solution to this tension. Causal inference in epidemiology consists in checking the logical coherence of a causality statement and determining whether what has been found grossly contradicts what we think we already know: how strong is the association? Is there a dose-response relationship? Does the cause precede the effect? Is the effect biologically plausible? Etc. This approach to causal inference can be traced back to the English philosophers David Hume and John Stuart Mill. On the other hand, the mode of establishing causality, devised by Jakob Henle and Robert Koch, which has been fruitful in bacteriology, requires that in every instance the effect invariably follows the cause (e.g., inoculation of Koch bacillus and tuberculosis). This is incompatible with epidemiological causality which has to deal with probabilistic effects (e.g., smoking and lung cancer), and is therefore invariant only for the population.

  4. Differential expression of genes in soybean in response to the causal agent of Asian soybean rust (Phakopsora pachyrhizi Sydow) is soybean growth stage-specific.

    Science.gov (United States)

    Panthee, Dilip R; Marois, James J; Wright, David L; Narváez, Dario; Yuan, Joshua S; Stewart, C Neal

    2009-01-01

    Understanding plant host response to a pathogen such as Phakopsora pachyrhizi, the causal agent of Asian soybean rust (ASR), under different environmental conditions and growth stages is crucial for developing a resistant plant variety. The main objective of this study was to perform global transcriptome profiling of P. pachyrhizi-exposed soybean (Glycine max) with susceptible reaction to the pathogen from two distinct developmental growth stages using whole genome Affymetrix microarrays of soybean followed by confirmation using a resistant genotype. Soybean cv. 5601T (susceptible to ASR) at the V(4) and R(1) growth stages and Glycine tomentella (resistant to ASR) plants were inoculated with P. pachyrhizi and leaf samples were collected after 72 h of inoculation for microarray analysis. Upon analyzing the data using Array Assist software at 5% false discovery rate (FDR), a total of 5,056 genes were found significantly differentially expressed at V(4) growth stage, of which 2,401 were up-regulated, whereas 579 were found differentially expressed at R(1) growth stage, of which 264 were up-regulated. There were 333 differentially expressed common genes between the V(4) and R(1) growth stages, of which 125 were up-regulated. A large difference in number of differentially expressed genes between the two growth stages indicates that the gene expression is growth-stage-specific. We performed real-time RT-PCR analysis on nine of these genes from both growth stages and both plant species and found results to be congruent with those from the microarray analysis.

  5. Identification and Characterisation of New Microbial Antagonists for Biocontrol of Monilinia laxa, the Causal Agent of Brown Rot on Stone Fruit

    Directory of Open Access Journals (Sweden)

    Peter Jeffries

    2013-10-01

    Full Text Available Monilinia laxa is the causal agent of brown rot disease on stone fruits, and also causes blossom wilt and twig canker. The common practice used to manage this disease is through fungicide treatments. However the demand to reduce fungicide inputs has been increasing and there is a growing number of reports of M. laxa strains that are resistant to fungicides. There is an urgent need to search for an alternative strategy to control the disease. This study focused on the isolation and characterisation of biological control agents (BCAs using indigenous isolates isolated from cherries and plums collected within the UK. A total of 192 isolates were screened against two strains of M. laxa in a series of in vitro dual culture tests. From this in vitro screen, 12 isolates were selected for a subsequent in vivo screen on detached fruits, which then narrowed these isolates down to two potential BCAs. These two strains were identified as Bacillus amyloliquefaciens/subtilis (isolate B91 and Aureobasidium pullulans (isolate Y126. The capability of these two potential BCAs to grow and survive at a range of temperatures likely to be experienced under field and storage conditions was studied in order to gain knowledge for product formulation and field application. Bacillus sp. B91 was shown to be a mesophilic bacterium that could grow at 10–25 °C but suffered significant mortality at 0 and 5 °C, while A. pullulans Y126 was both mesophilic and psychrotolerant as it grew between 0–25 °C with the optimum at 20 °C. When all nutrients were removed, Y126 was able to survive for several weeks in all test temperatures (0–25 °C but showed significant mortality at 25 °C. The capability of B91 to survive at 20 and 25 °C was higher than at low temperatures (0–15 °C. In addition, the modes of action of the potential BCAs were studied. B91 was shown to produce soluble and volatile organic compounds that inhibited M. laxa, while A. pullulans Y126 did not

  6. 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.

  7. Evaluación a nivel de laboratorio del efecto de 7 extractos vegetales para el control de Colletotrichum sp agente causal de la antracnosis en el cultivo de tomate de árbol - Evaluación a nivel de laboratorio del efecto de 7 extractos vegetales para el control de Colletotrichum sp agente causal de la antracnosis en el cultivo de tomate de árbol

    OpenAIRE

    Christian Andrei Chacin Zambrano; Mary Lady Blanco Medina; Sonia Cecilia Sanchez; Carlos Acevedo Isidro

    2013-01-01

    Was evaluated in the laboratory the effect of seven plant extracts of Neem leaves and fruit (Azadirachta indica) leaves of lemon grass (Swinglea glutinosa), leaves of papaya (Carica papaya), Pringamosa leaves (Urtica dioica), eucalyptus leaves (Eucalyptus camaldulensis Dehn) fruits of garlic (Allium sativum L.) and fruits of pepper (Capsicum annuum) in the control of the fungus Colletotrichum sp causal agent of anthracnose in tomato crop tree (Cyphomandra betacea). The pathogen was isolated o...

  8. Functional and biophysical studies on four ceratoplatanins from the fungus Moniliophthora perniciosa, causal agent of the Witche's broom disease

    Energy Technology Data Exchange (ETDEWEB)

    Barsottini, M.; Zaparoli, G.; Garcia, O.; Pereira, G.A.G. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Oliveira, J.F.; Tiezzi, H.O.; Ambrosio, A.L.B.; Dias, S.M.G. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: Ceratoplatanin (CP) is a secreted protein of 12.4 kDa initially identified in culture filtrates of the disease ascomycete Ceratocystis fimbriata f. sp. platani, etiological agent of the canker stain disease. CP is also the founding member of the namesake protein family, which contains fungal-secreted proteins involved in various stages of the host-fungus interaction and may act as phytotoxins or elicitors of defense response. Besides the low molecular weight, CPs have a high percentage of hydrophobic residues and share two conserved intramolecular disulfide bonds. It has been suggested that CPs have important physiological functions, including interaction with cell wall or cell membrane and manipulation of the host's defense system. Furthermore, a recent work showed that the ceratoplatanin from C. fimbriata has some degree of affinity for the saccharide 4-N-acetylglucosamine. However, its precise molecular function remains elusive. Five putative CPs have been identified in Moniliophthora perniciosa a basidiomycete fungus responsible for great economic losses in cocoa industry in the form of Witches' broom disease (WBD) , four of which had their crystal structures resolved by our group. In this work we report biophysical and functional studies on these MpCPs aiming at understanding their role and importance during the WBD progression. (author)

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

    Directory of Open Access Journals (Sweden)

    Antonio Fernando Crepaldi

    2012-12-01

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

  10. Hymenoscyphus fraxineus vs. Hymenoscyphus albidus – A comparative light microscopic study on the causal agent of European ash dieback and related foliicolous, stroma-forming species

    Science.gov (United States)

    Baral, Hans-Otto; Bemmann, Martin

    2014-01-01

    Five species of Hymenoscyphus that fruit on black stromatized parts of dead leaves of deciduous trees are presented, giving details on their morphological and ecological characteristics. Several of these species have previously been misplaced in rutstroemiaceous genera because of the presence of a substratal stroma. However, the heteropolar, scutuloid ascospores with an often hook-like lateral protrusion at the rounded apex and the ascus apical ring of the Hymenoscyphus-type represent two reliable morphological characteristics that, together with molecular data, provide clear evidence for their placement in the genus Hymenoscyphus (Helotiaceae). Among the species treated is Hymenoscyphus fraxineus (=Hymenoscyphus pseudoalbidus), the causal agent of the European ash dieback disease. Since 1992 this species started within Europe to replace the rather uncommon Hymenoscyphus albidus, which is likewise confined to leaves of Fraxinus. Hy. fraxineus has been recorded already since 1990 in Eastern Asia (Japan, Korea, northeast of China), where it had been initially misidentified as Lambertella albida (≡Hy. albidus). In these regions, it occurs as a harmless saprotroph on Fraxinus mandshurica and Fraxinus rhynchophylla, suggesting that those populations are native while the European ash dieback disease has a recent Eastern Asiatic origin. The distinctly higher genetic diversity found in Japanese Hy. fraxineus in contrast to European Hy. fraxineus supports this view. Genetic similarities between Japanese Hy. fraxineus and European Hy. albidus suggest that also Hy. albidus might be a descendant of Asian Hy. fraxineus, though having invaded Europe much earlier. However, consistent genetic deviation between European and Asian Hy. fraxineus at two nucleotide positions of the ITS region indicates that the European ash disease originates from a region different from the presently known areas in Eastern Asia. Our results underline the importance of detailed morphological studies

  11. O trabalho do agente comunitário na promoção da saúde: revisão integrativa da literatura

    Directory of Open Access Journals (Sweden)

    Iara Cristina Pereira

    2013-06-01

    Full Text Available O presente artigo é uma revisão integrativa que teve como objetivo avaliar as evidências disponíveis na literatura sobre o desenvolvimento de estratégias operacionalizadas pelos agentes comunitários de saúde em prol da promoção da saúde. Para a seleção dos estudos foram usadas três bases de dados: BDTD, LILACS e SciELO. Foram encontradas 2.179 publicações, das quais 58 foram selecionadas para análise. Os resultados foram sistematizados em três categorias empíricas: A promoção da saúde: desafios na reorientação do modelo assistencial, A prática educativa no cotidiano de trabalho dos ACS e A formação profissional na perspectiva da Atenção Primária em Saúde. Concluiu-se que a construção de um modelo assistencial baseado na promoção da saúde requer a incorporação de novas práticas formativas, assistenciais e institucionais.

  12. Os agentes sociais da rede de proteção e atendimento no enfrentamento da exploração sexual comercial Social agents from protection networks in fighting commercial sexual exploitation

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Pereira Alberto

    2012-01-01

    Full Text Available Neste artigo, apresentam-se dados de pesquisa sobre a percepção dos Agentes Sociais que atuam no enfrentamento da exploração sexual comercial de crianças e adolescentes. As entidades caracterizam-se por Organizações Governamentais, Organizações Não-Governamentais, Sistema de Justiça e Instâncias de Direitos. Compõem uma Rede de 15 instituições e foram entrevistados 31 Agentes Sociais de 12 delas. Utilizou-se um questionário composto de questões abertas e fechadas sobre: Conhecimento do Sistema de Proteção; Percepção da ESCCA; Formas de Enfrentamento da ESCCA; Procedimentos e Medidas em casos de suspeitas, identificações, denúncias e notificações. A maioria dos Agentes Sociais tem conhecimento do papel da instituição, embora alguns desconheçam parte da Legislação e as formas de se efetivar na prática o papel daquelas e a articulação interinstitucional.This article shows the data collected in a research regarding the perception of Social Agents who act in fighting children and adolescents' commercial sexual exploitation. The networking is composed by Governmental Organizations, Non-governmental Organizations, Justice System and Human Rights entities. They compose a network of 15 institutions, and 31 Social Agents who belonged to 12 of them were interviewed. It was used a questionnaire composed by open and closed questions about protection systems knowledge; perception of children and adolescents' commercial sexual exploitation; forms of fighting children and adolescents' commercial sexual exploitation; procedures and actions in case of suspicion, identification, denunciation and notification. Most of the Social Agents who make part of the network know the role of the institution where they work, although some of them do not know part of the Legislation which deals with this problematic and they also do not know the forms to effectuate in practice the purpose of the Legislation and its inter

  13. Especificação normativa de agentes institucionais e da interacção entre agentes

    OpenAIRE

    Pacheco, Olga

    2001-01-01

    O trabalho apresentado nesta dissertação teve por objectivo essencial, contribuir para o estudo formal de conceitos e de modelos adequados para a especificação normativa de entidades colectivas organizadas e que permitissem uma análise rigorosa de tais entidades. Tendo por base o conceito jurídico de pessoa colectiva e as relações jurídicas de mandato e de representação, introduzem-se os conceitos de papel, acção num papel, representação entre agentes, contrato e agente instit...

  14. Agentes antitumorais inibidores da angiogênese: modelos farmacofóricos para inibidores da integrina anb3 Angiogenesis inhibitors antitumor agents: pharmacophore models to anb3 antagonists

    Directory of Open Access Journals (Sweden)

    Thais Horta Álvares da Silva

    2007-03-01

    Full Text Available O câncer é, atualmente, uma das principais causas de morte no mundo. A angiogênese, formação de novos vasos capilares a partir de células endoteliais, é essencial para vários processos fisiopatológicos, tais como o desenvolvimento e a disseminação dos tumores. As integrinas são uma família de receptores de superfície que estão envolvidos na angiogênese, na qual a integrina anb3 exerce papel importante. Os antagonistas da integrina anb3 têm efeitos diretos na prevenção do crescimento, angiogênese e metástase tumorais. A avaliação in vitro frente à integrina anb3 de coleções de ciclopeptídeos levou a compostos muito ativos e seletivos. Antagonistas não-peptídicos da integrina anb3 também foram planejados e sintetizados. A partir da determinação da estrutura tridimensional da integrina anb3 complexada com um inibidor, tornou-se possível o planejamento racional de ligantes com alta afinidade. Além disto, estes estudos permitiram a validação e o refinamento de modelo farmacofórico para os inibidores da integrina anb3.Cancer is one of the leading causes of death. Angiogenesis, the growth of new blood vessels, is essential for tumor development and spreading. Integrins are a family of surface receptors that are involved in angiogenesis. The anb3 integrin plays an important role in tumor angiogenesis. anb3 inhibitors have direct effects to prevent tumor metastases, growth and angiogenesis. In vitro screening of cyclic peptide libraries led to highly active and anb3-selective compounds. Non-peptidic anb3 antagonists were also designed and synthesized. The crystal structure of the anb3 integrin in complex with RGD ligant allowed structure-based rational design of ligands and validation of pharmacophore model to anb3 antagonists.

  15. 麻疯树根腐病的病原鉴定%Identification of the Causal Agent of Root Rot Disease of Jatropha curcas L.in Luodian County

    Institute of Scientific and Technical Information of China (English)

    吴跃开; 欧国腾; 朱秀娥; 余金勇

    2011-01-01

    [Objective] The aim was to identify the causal agent of root rot disease of Jatropha curcas L. In Luodian County. [ Method ] Typical root rot samples were collected from different planting areas of Jatropha curcas L. In Luodian County, and then pathogens of the root rot samples were isolated, cultured, made a pathogenic test and observed under the microscope. [Result] The causal agent of root rot disease of Jatropha curcas L. Was Fusarium solani ( Martius) Appel & Wollenweber. [ Conclusion] The research provides reference for the effective prevention and control of root rot disease of Jatropha curcas L. In Luodian County.%[目的]鉴定麻疯树根腐病的病原.[方法]从罗甸县境内的不同麻疯树种植地点采集典型的根腐病病根标本,并对其病原物进行了分离培养、致病性测试以及形态特征观察.[结果]最终确认麻疯树根腐病病原菌为腐皮镰孢菌(Fusarium solani).[结论]为贵州罗甸县境内麻疯树根腐病的有效防治提供了参考.

  16. Atividade in vitro do extrato de própolis contra agentes bacterianos da mastite bovina In vitro activity of propolis extract against bovine mastitis bacterial agents

    Directory of Open Access Journals (Sweden)

    Andrea Pinto Loguercio

    2006-02-01

    Full Text Available Este trabalho foi desenvolvido com o objetivo de avaliar a atividade in vitro do extrato alcoólico de própolis, contra agentes da mastite bovina, comparando-o aos principais antimicrobianos utilizados no tratamento convencional. Foram utilizados 36 isolados coagulase-positivos de Staphylococcus sp. e 27 isolados de Streptococcus sp.; 94,4% dos Staphylococcus sp. e 85,2% dos Streptococcus sp. foram susceptíveis ao extrato de própolis.The present study aimed to determine the in vitro activity of propolis extract, comparing it to the most common antibacterial drugs against bovine mastitis bacterial agents. Thirty-six isolates of coagulase-positive Staphylococcus sp. and twenty-seven of Streptococcus sp. were analyzed. Coagulase-positive Staphylococcus (94.4% and Streptococcus sp. (85.2% showed susceptibility to propolis extract.

  17. Acción inhibitoria de una cepa de Zymomonas mobilis mobilis aislada de caña de azúcar sobre Xanthomonas citri subsp. citri, agente causal de la cancrosis de los cítricos Inhibition of Xanthomonas citri subsp. citri, causal agent of citrus canker, by a strain of Zymomonas mobilis mobilis isolated from sugarcane

    Directory of Open Access Journals (Sweden)

    María E. Romero

    2008-06-01

    a wide range of microorganisms pathogenic to man, animals, and plants. An important problem to solve with antimicrobial treatments is the development of resistance in these microorganisms, including phytopathogenic bacteria, to the currently used active ingredients. In this study, antagonism tests with cells (cross-streaking and cell-free culture supernatants (CCS (agar diffusion test from Zm cultures, isolated from sugarcane juice in Tucumán, were carried out, measuring activity against Xanthomonas citri subsp. citri (Xcc, the causal agent of citrus canker. Xcc isolates sensitive (Xc and resistant (Xcr to copper pesticides were included in these tests. Results showed that indicator bacteria were completely inhibited by cells of Zm, which had a bactericide effect. Both Xc and Xcr were sensitive to the CCS in the agar diffusion method. Previous studies had revealed the deleterious effects of metabolites from Zm on cell membranes of E. coli AB1133, inhibiting the respiration of the bacteria inmediately after CCS addition. On the basis of these results, the effects of CCS on Xcc respiration were studied, verifyng a similar response. This would indicate that the site of action of these antimicrobial compounds is also located at the cell membrane of the bacteria under study. Based on these results, additional studies are suggested to evaluate Zm-derived products on the control of diseases that affect economically important crops, such as citrus canker.

  18. Principais características da raiz de cenoura na perspectiva de agentes da cadeia produtiva Main carrot root attributes based on stake holders perceptions

    Directory of Open Access Journals (Sweden)

    Silvia S Onoyama

    2011-09-01

    Full Text Available Procurou-se verificar quais são as características mais importantes da raiz de cenoura sob a ótica dos agentes da cadeia produtiva de cenoura. Para tanto, foram realizadas visitas e entrevistas com produtores, empresas de semente, vendedores de insumos, lavadores, processadores, atacadistas e gerentes de supermercados, comparando-se esses resultados com os da pesquisa de percepção de consumidores de supermercados do Distrito Federal. Em ambos os casos, utilizou-se questionário estruturado com perguntas fechadas nas quais os entrevistados classificaram os atributos segundo notas que variaram de 1 (nenhuma importância a 5 (muito importante. Para verificar a ordenação de importância dos atributos e os contrastes das médias, utilizou-se o método estatístico de análise de dados categóricos. O resultado da pesquisa indicou que os consumidores estão preocupados com valores nutricionais, textura, cor externa e sabor da cenoura. Já os demais agentes da cadeia atentaram mais para as características relacionadas com a padronização, com a coloração externa e com o ombro verde. Foram detectadas diferenças de percepção entre os agentes da cadeia, em especial dos consumidores, para os quais foram observadas diferenças nas respostas em função do gênero, idade, grau de escolaridade, estado civil e localização do supermercado. Estes resultados são muito importantes para o direcionamento de projetos de pesquisa com cenoura, que precisa atender as exigências tanto do setor produtivo quanto dos consumidores.The present investigation aimed at elucidating the carrot attributes which stake holders view as the most important. A research was carried out with carrot growers, seed companies, supplier salespersons, washers, food processors, wholesalers and supermarket managers and was compared to the perception of consumers from supermarkets located in the Federal District of Brazil. Data sets were collected through structured interviews

  19. Use of the montmorillonite as crosslink agents for chitosan; Uso da montmorilonita como agente de reticulacao para a quitosana

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Rossemberg C.; Lima, Rosemary S. Cunha; Braga, Carla R. Costa [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Programa de Pos-graduacao em Ciencia e Engenharia de Materiais; Fook, Marcus V. Lia; Silva, Suedina M. Lima [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais

    2009-07-01

    The montmorillonite (the main constituent of bentonite) has been the most commonly used inorganic load in the formation of nanocomposites chitosan / layered silicate. To evaluate its effect as an agent for the reticulation of chitosan, a sodium montmorillonite, Cloisite Na{sup +}, supplied by Southern Clay Products, Texas, USA, was used. For the reticulation of chitosan dispersions of chitosan / Cloisite Na{sup +} were prepared in different proportions and the obtained films characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TG). The results indicated that the Cloisite Na{sup +} was for efficient and the reticulation of the chitosan and can be used in place of sulfuric acid, which is one of the most common reticulants for chitosan. (author)

  20. Restriction enzyme improves the efficiency of genetic transformations in Moniliophthora perniciosa, the causal agent of witches’ broom disease in Theobroma cacao

    Directory of Open Access Journals (Sweden)

    Francis Julio Fagundes Lopes

    2008-02-01

    Full Text Available The presence of restriction enzymes in the transformation mixture improved the efficiency of transformation in Moniliophthora perniciosa. The influence of the vector shape (linear or circular, the patterns of plasmid integration in genomic sites and the influence of the promoter used to express the gene marker were also analyzed. The addition of BamHI or NotI increased the number of transformants by 3-10-fold and 3-fold, respectively, over the control without added enzyme. The use of pre-linearized plasmid did not increase the transformation efficiency in comparison with the circular plasmid. However, the frequency of multi-copy transformants increased significantly. The transformation procedure here reported resulted in better production of protoplasts and transformation efficiency. In addition, the time necessary for the detection of the first transformants and the number of insertions were reduced.A presença de enzima de restrição na mistura de transformação aumentou a eficiência da transformação em Moniliophthora perniciosa. A influência da forma do vetor (linear ou circular, o padrão de integração do plasmídeo nos sítios genômicos e a influência do promotor usado para expressar o gene marcador foram também analisados. A adição de BamHI ou NotI aumentou o número de transformantes 3-10 vezes e 3 vezes, respectivamente, em relação ao controle sem a adição da enzima. O uso de plasmídeos pré-linearizados não aumentou a eficiência da transformação quando comparado à eficiência obtida com plasmídeos circulares. No entanto, a freqüência de transformantes multi-cópias aumentou significativamente. Juntos os procedimentos reportados aqui resultaram em processos mais eficientes de produção de protoplastos e transformação, onde o tempo necessário para o aparecimento dos transformantes e o número de inserções múltiplas foi reduzido.

  1. 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.

  2. Glucanases and Chitinases as Causal Agents in the Protection of Acacia Extrafloral Nectar from Infestation by Phytopathogens1[W][OA

    Science.gov (United States)

    González-Teuber, Marcia; Pozo, María J.; Muck, Alexander; Svatos, Ales; Adame-Álvarez, Rosa M.; Heil, Martin

    2010-01-01

    Nectars are rich in primary metabolites and attract mutualistic animals, which serve as pollinators or as an indirect defense against herbivores. Their chemical composition makes nectars prone to microbial infestation. As protective strategy, floral nectar of ornamental tobacco (Nicotiana langsdorffii × Nicotiana sanderae) contains “nectarins,” proteins producing reactive oxygen species such as hydrogen peroxide. By contrast, pathogenesis-related (PR) proteins were detected in Acacia extrafloral nectar (EFN), which is secreted in the context of defensive ant-plant mutualisms. We investigated whether these PR proteins protect EFN from phytopathogens. Five sympatric species (Acacia cornigera, A. hindsii, A. collinsii, A. farnesiana, and Prosopis juliflora) were compared that differ in their ant-plant mutualism. EFN of myrmecophytes, which are obligate ant-plants that secrete EFN constitutively to nourish specialized ant inhabitants, significantly inhibited the growth of four out of six tested phytopathogenic microorganisms. By contrast, EFN of nonmyrmecophytes, which is secreted only transiently in response to herbivory, did not exhibit a detectable inhibitory activity. Combining two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis with nanoflow liquid chromatography-tandem mass spectrometry analysis confirmed that PR proteins represented over 90% of all proteins in myrmecophyte EFN. The inhibition of microbial growth was exerted by the protein fraction, but not the small metabolites of this EFN, and disappeared when nectar was heated. In-gel assays demonstrated the activity of acidic and basic chitinases in all EFNs, whereas glucanases were detected only in EFN of myrmecophytes. Our results demonstrate that PR proteins causally underlie the protection of Acacia EFN from microorganisms and that acidic and basic glucanases likely represent the most important prerequisite in this defensive function. PMID:20023149

  3. Brominated and radioiodinated derivatives of methylphenidate (MP): Potential imaging agents for the dopamine (DA) transporter

    Energy Technology Data Exchange (ETDEWEB)

    Pan, D.; Gatley, S.J.; Dewey, S.L. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1994-05-01

    MP (Ritalin) is a psychomotor stimulant used in the treatment of attention-deficit hyperactivity disorder. The therapeutic properties of MP are thought to be mediated by its binding to a site on the DA transporter, resulting in inhibition of DA reuptake and enhanced levels of synaptic dopamine. MP also inhibits reuptake of norepinephrine (NE) in vitro. MP has two chiral centers, but its pharmacological activity is believed due solely to the d-threo isomer. We have found that d,l-threo-C-11 MP has favorable properties for PET studies, and therefore examined the effects of incorporating halogen atoms into the phenyl ring of MP, with a view to preparing C-11 and I-123 MP analogs as potential PET/SPECT tracers. We synthesized the 2-, 3- and 4-bromo MP analogs from the corresponding bromophenylacetonitriles by modification of the original synthesis of MP. In in vitro binding assays all three d,l-threo bromo compounds had higher affinities than MP for DA transporter sites labeled with tritiated WIN 35,428 (3->4-, 2->MP). They also showed high activity with NE reuptake sites labeled with tritiated nisoxetine. They were active in vivo as demonstrated by inhibition of heart uptake of tritiated NE in the mouse, and elevation of striatal extracellular DA (microdialysis) and stimulation of locomotor activity in the rat.

  4. Predictors for dioxin accumulation in residents living in Da Nang and Bien Hoa, Vietnam, many years after Agent Orange use.

    Science.gov (United States)

    Pham, Diem T; Nguyen, Hang M; Boivin, Thomas G; Zajacova, Anna; Huzurbazar, Snehalata V; Bergman, Harold L

    2015-01-01

    Agent Orange (AO) was the main defoliant used by the US in Vietnam from 1961 to 1971; AO was contaminated with dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD). Three major dioxin “hot spots” remain from previous AO storage and use at former US bases at Bien Hoa, Da Nang, and Phu Cat, posing potential health risks for Vietnamese living on or near these hot spots. We evaluated potential risk factors contributing to serum TCDD levels in Vietnamese residents at and near contaminated sites in Da Nang and Bien Hoa, Vietnam. We used multiple linear regression to analyze possible associations of blood dioxin concentrations with demographic, socioeconomic, lifestyle, and dietary risk factors for residents living on or near these hot spots. For the Da Nang study, fish farming on the site, living on property flooded from monsoon rains, and age were among the factors showing significant positive associations with serum TCDD concentrations. For the Bien Hoa study, fish farmers working at this site and their immediate family members had significantly higher serum TCDD concentrations. Our results suggest that water-related activities, especially fish-farming, at the hot spots increased the risk of exposure to dioxin. PMID:25463251

  5. Evaluación a nivel de laboratorio del efecto de 7 extractos vegetales para el control de Colletotrichum sp agente causal de la antracnosis en el cultivo de tomate de árbol - Evaluación a nivel de laboratorio del efecto de 7 extractos vegetales para el control de Colletotrichum sp agente causal de la antracnosis en el cultivo de tomate de árbol

    Directory of Open Access Journals (Sweden)

    Christian Andrei Chacin Zambrano

    2013-08-01

    Full Text Available Was evaluated in the laboratory the effect of seven plant extracts of Neem leaves and fruit (Azadirachta indica leaves of lemon grass (Swinglea glutinosa, leaves of papaya (Carica papaya, Pringamosa leaves (Urtica dioica, eucalyptus leaves (Eucalyptus camaldulensis Dehn fruits of garlic (Allium sativum L. and fruits of pepper (Capsicum annuum in the control of the fungus Colletotrichum sp causal agent of anthracnose in tomato crop tree (Cyphomandra betacea. The pathogen was isolated on PDA medium from tomato fruit tree, the extracts were obtained taking into account the process by (Marin, et. Al 2007, which consists of chopping and blending plant material deposited in plastic bucket, add water ratio 2.5:1 (water: sample processed, vol.: w, subjecting to fermentation for 24 hours. The produto was filtered using sterile gauze and package them for further evaluation. The concentrations of the treatments that worked were 25, 50, 75 and 100% of the infectious agent, determining the degree of inhibition of the pathogen in Petri dishes. The best results were obtained with the application of eucalyptus leaves, since its effect was 100% at all concentrations, without neglecting the fruits of the Neem and garlic with inhibition percentages of 75 and 60% respectively, had a behavior directly proportional to the concentrations used, since the greater the amount of extract the inhibitory effect was better in this case 75% and 100%.

  6. 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.

  7. Effect of carbon and nitrogen sources on growth and biological efficacy of Pseudomonas fluorescens and Bacillus subtilis against Rhizoctonia solani, the causal agent of bean damping-off.

    Science.gov (United States)

    Peighamy-Ashnaei, S; Sharifi-Tehrani, A; Ahmadzadeh, M; Behboudi, K

    2007-01-01

    One of the most important environmental factors that regulate the growth and antagonistic efficacy of biocontrol agents is the medium. The aim of this paper was to find the nitrogen and carbon sources that provide maximum biomass production of strains P-5 and P-6 (Pseudomonas fluorescens), B-3 and B-16 (Bacillus subtilis) and minimum cost of media, whilst maintaining biocontrol efficacy. All of the strains were grown in seven liquid media (pH=6.9) including: sucrose + yeast extract, molasses of sugar beet + yeast extract in 2:1 and 1:1 w/w ratios, molasses of sugar beet + urea, nutrient broth, molasses and malt extract, at an initial inoculation of 1 x 10(5) CFU ml(-1). Cells from over night cultures used to inoculate soil at 1 x 10(9) CFU cm(-3) soil. At the same time, fungal inoculum (infected millet seed with Rhizoctonia solani) was added to soil at the rate of 2 g kg(-1) soil. Results indicated that growth of P-6, B-3 and B-16 in molasses + yeast extract (1:1 w/w) medium was significantly higher than in the other media. Molasses + yeast extract (1:1 and 2:1 w/w) media supported rapid growth and high cell yields in P-5. In greenhouse condition, results indicated that the influence of the media on the biocontrol efficacy of P-5, P-6, B-3 and B-16 was the same and Pseudomonas fluorescens P-5 in molasses and malt extract media reduced the severity of disease up to 72.8 percent. On the other hand, there were observed significant differences on bean growth after one month in greenhouse. P-5 in molasses + yeast extract (1:1 w/w) medium had the most effects on bean growth promotion. In this study molasses media showed good yield efficacy in all of the strains. The high sucrose concentration in molasses justifies the high biomass in all of the strains. Also, the low cost of molasses allows its concentration to be increased in media. On the other hand, yeast extract was the best organic nitrogen source for antagonist bacteria but it is expensive for an industrial process

  8. The effect of locust bean gum (LBG)-based edible coatings carrying biocontrol yeasts against Penicillium digitatum and Penicillium italicum causal agents of postharvest decay of mandarin fruit.

    Science.gov (United States)

    Parafati, Lucia; Vitale, Alessandro; Restuccia, Cristina; Cirvilleri, Gabriella

    2016-09-01

    Strains belonging to Wickerhamomyces anomalus, Metschnikowia pulcherrima and Aureobasidium pullulans species were tested in vitro as biocontrol agents (BCAs) against the post-harvest pathogenic molds Penicillium digitatum and Penicillium italicum. Moreover, studies aimed at screening the antifungal activity of selected yeast strains in vivo conditions against P. digitatum and P. italicum, and investigated the efficacy of a polysaccharidic matrix, locust bean gum (LBG), enriched with the tested BCAs, in controlling postharvest decays in artificially inoculated mandarins. The population dynamics of BCAs on wounds and the magnitude of peroxidase (POD) and superoxide dismutase (SOD) in fruit tissues were also investigated after treatments of mandarins with antagonistic yeasts. W. anomalus BS91, M. pulcherrima MPR3 and A. pullulans PI1 provided excellent control of postharvest decays caused by P. digitatum and P. italicum on mandarins, both when the yeasts were used alone and in combination with LBG, which enhanced the yeast cell viability over time. Finally, the increased activity of POD and lower decrease in SOD activity in response to BCAs application in mandarin fruits confirmed their involvement in the biocontrol mechanism. PMID:27217363

  9. Biocontrol of Botrytis allii Munn the Causal Agent of Neck Rot, the Post Harvest Disease in Onion, by use of a New Iranian Isolate of Streptomyces

    Directory of Open Access Journals (Sweden)

    M. Jorjandi

    2009-01-01

    Full Text Available Problem statement: Soil actinomycetes particularly Streptomyces spp. showed antagonistic activity against wide range of plant pathogens. In the recent decades they have attracted high interests as biocontrol agents. Onion neck rot or gray mold caused by Botrytis allii have imposed economic post harvest damages to onion bulbs and decreased its storage durability and market value. Approach: To investigate for biocontrol means against the pathogen, antagonistic activity of 50 isolates of soil Actinomycetes were assayed through agar disk method and dual culture bioassays. Active isolates were exposed to chloroform for detection of antibiotic. Minimum Inhibitory Concentration (MIC value and solubility of active crude extract in organic solvents were determined for Streptomyces isolate No. 347 which showed a unique and stable property of inhibiting Botrytis allii. To investigate the antagonistic effect of Streptomyces isolate No. 347 on control of onion gray mold, 4 different treatments were tested by means of Tukey HSD test. Results: From the tested isolates, 13 showed anti gray mold activities. Exposure of active isolates to chloroform revealed that Streptomyces isolates No. 347, 263 and 350 retained their antifungal activities. The active metabolite(s of Streptomyces isolate No. 347 was polar, soluble in H2O but insoluble in chloroform and methanol. MIC of the crude was determined as 0.05 mg mL-1 against B. allii. Stability of the active crude in distilled water at room temperature (12-30°C was about 6 months. Statistical studies indicated that Streptomyces isolates No. 347 can decrease losses of neck rot with significant level (pConclusion: The future goals include investigation of the antifungal genes in active isolates as candidates for genetic engineering of onion for increased tolerance against B. allii.

  10. TRABALHO DO AGENTE COMUNITÁRIO DE SAÚDE NO CONTROLE DA HANSENÍASE

    Directory of Open Access Journals (Sweden)

    Olga Maria de Alencar

    2012-01-01

    Full Text Available El objetivo fue describir el proceso de trabajo de los Agentes Comunitarios de Salud en el acompañamiento a las personas con lepra. La profesión es nueva, con actuación en el Sistema Único de Salud y se centra en la prevención de enfermedades y promoción de la salud. Estudio cuantitativo (n = 331, en Maranhão, Pará, Tocantins y Piauí, entre agosto/2009 y julio/2010. Los datos fueron analizados con el EPI-INFO. 93% de Agentes son mujeres, edad media 25 años; 84,2% concluyeron la escuela secundaria; 87,1% acompañan los casos de lepra; 55,3% utilizan herramienta para registrar los casos; 82,2% encaminan los casos sospechosos a la unidad básica de salud; 43,0% orientan sobre la lepra; 53,2% tienen formación en lepra. Grupo predominante de mujeres adultas jóvenes, con educación secundaria. A pesar de la baja disponibilidad de capacitación en las acciones de control de la lepra, los Agentes monitoran los pacientes en su territorio.

  11. Identification of the Causal Agent of Stem and Branch Canker Disease of Jatropha curcas L.%麻疯树枝干溃疡病的病原鉴定

    Institute of Scientific and Technical Information of China (English)

    吴跃开; 欧国腾; 孙建昌

    2012-01-01

    Stem and branch canker disease is one of the most serious diseases occurred in the biofuel plantation (Jatropha curcas L.) in Luodian County of Guizhou province, usually resulting in the death of the seedlings, branches, stems or even the whole big trees. The damage characteristics and the sypotoms of the disease were introduced; and according to the results of morphological study and pathogenicity inoculation test, the causal agent of the canker disease was identified as Botryosphaeria.dothidea(anamorph:Fusicoccum aesculi).%麻疯树(Jatropha curcas L.)枝干溃疡病是麻疯树主要病害种类之一,常引起幼苗、枝干枯死,甚至全株死亡.对该病的危害特点、病症特征进行了介绍,并根据形态学特征观测及致病性接种试验的结果,将其病原鉴定为Botryosphaeria dothidea,其无性型为Fusicoccum aesculi.

  12. Endophytic bacteria from Piper tuberculatum Jacq.: isolation, molecular characterization, and in vitro screening for the control of Fusarium solani f. sp piperis, the causal agent of root rot disease in black pepper (Piper nigrum L.).

    Science.gov (United States)

    Nascimento, S B; Lima, A M; Borges, B N; de Souza, C R B

    2015-01-01

    Endophytic bacteria have been found to colonize internal tissues in many different plants, where they can have several beneficial effects, including defense against pathogens. In this study, we aimed to identify endophytic bacteria associated with roots of the tropical piperaceae Piper tuberculatum, which is known for its resistance to infection by Fusarium solani f. sp piperis, the causal agent of black pepper (Piper nigrum) root rot disease in the Amazon region. Based on 16S rRNA gene sequence analysis, we isolated endophytes belonging to 13 genera: Bacillus, Paenibacillus, Pseudomonas, Enterobacter, Rhizobium, Sinorhizobium, Agrobacterium, Ralstonia, Serratia, Cupriavidus, Mitsuaria, Pantoea, and Staphylococcus. The results showed that 56.52% of isolates were associated with the phylum Proteobacteria, which comprised α, β, and γ classes. Other bacteria were related to the phylum Firmicutes, including Bacillus, which was the most abundant genus among all isolates. Antagonistic assays revealed that Pt12 and Pt13 isolates, identified as Pseudomonas putida and Pseudomonas sp, respectively, were able to inhibit F. solani f. sp piperis growth in vitro. We describe, for the first time, the molecular identification of 23 endophytic bacteria from P. tuberculatum, among which two Pseudomonas species have the potential to control the pathogen responsible for root rot disease in black pepper in the Amazon region. PMID:26214435

  13. Pyrenophora bromi, causal agent of brownspot of bromegrass, expresses a gene encoding a protein with homology and similar activity to Ptr ToxB, a host-selective toxin of wheat.

    Science.gov (United States)

    Andrie, Rachael M; Ciuffetti, Lynda M

    2011-03-01

    Ptr ToxB, encoded by ToxB, is one of multiple host-selective toxins (HST) produced by the wheat pathogen Pyrenophora tritici-repentis. Homologs of ToxB are found in several ascomycetes, including sister species Pyrenophora bromi, causal agent of brownspot of bromegrass. Due to the close evolutionary relatedness of P. tritici-repentis and P. bromi and that of their grass hosts, we hypothesized that homologs of ToxB in P. bromi may act as HST in the disease interaction between P. bromi and bromegrass. A representative set of transcriptionally active P. bromi ToxB genes were heterologously expressed in Pichia pastoris and the resultant proteins tested for their ability to act as HST on bromegrass. The tested Pyrenophora bromi ToxB (Pb ToxB) proteins were not toxic to bromegrass; thus, Pb ToxB does not appear to function as an HST in the P. bromi-bromegrass interaction. Instead, we revealed that the Pb ToxB proteins can be toxic to Ptr ToxB-sensitive wheat, at levels similar to Ptr ToxB, and the corresponding P. bromi ToxB genes are expressed in P. bromi-inoculated wheat. Our data suggest that P. bromi possesses the potential to become a wheat pathogen and highlights the importance of investigating the interaction between P. bromi and wheat. PMID:21091157

  14. Endophytic bacteria from Piper tuberculatum Jacq.: isolation, molecular characterization, and in vitro screening for the control of Fusarium solani f. sp piperis, the causal agent of root rot disease in black pepper (Piper nigrum L.).

    Science.gov (United States)

    Nascimento, S B; Lima, A M; Borges, B N; de Souza, C R B

    2015-07-06

    Endophytic bacteria have been found to colonize internal tissues in many different plants, where they can have several beneficial effects, including defense against pathogens. In this study, we aimed to identify endophytic bacteria associated with roots of the tropical piperaceae Piper tuberculatum, which is known for its resistance to infection by Fusarium solani f. sp piperis, the causal agent of black pepper (Piper nigrum) root rot disease in the Amazon region. Based on 16S rRNA gene sequence analysis, we isolated endophytes belonging to 13 genera: Bacillus, Paenibacillus, Pseudomonas, Enterobacter, Rhizobium, Sinorhizobium, Agrobacterium, Ralstonia, Serratia, Cupriavidus, Mitsuaria, Pantoea, and Staphylococcus. The results showed that 56.52% of isolates were associated with the phylum Proteobacteria, which comprised α, β, and γ classes. Other bacteria were related to the phylum Firmicutes, including Bacillus, which was the most abundant genus among all isolates. Antagonistic assays revealed that Pt12 and Pt13 isolates, identified as Pseudomonas putida and Pseudomonas sp, respectively, were able to inhibit F. solani f. sp piperis growth in vitro. We describe, for the first time, the molecular identification of 23 endophytic bacteria from P. tuberculatum, among which two Pseudomonas species have the potential to control the pathogen responsible for root rot disease in black pepper in the Amazon region.

  15. Análise de causalidade da relação entre sangramento e letalidade de Síndromes Coronarianas Agudas Causality analysis of the relationship between bleeding and lethality in Acute Coronary Syndromes

    Directory of Open Access Journals (Sweden)

    Luis Cláudio Lemos Correia

    2012-06-01

    Full Text Available FUNDAMENTO: Eventos hemorrágicos em Síndromes Coronarianas Agudas (SCA apresentam associação independente com óbito em registros multicêntricos internacionais. No entanto, essa associação não foi testada em nosso meio e a verdadeira relação causal entre sangramento e óbito não está plenamente demonstrada. OBJETIVO: Testar as hipóteses de que: (1 sangramento maior é preditor independente de óbito hospitalar em SCA; (2 a relação entre esses dois desfechos é causal. MÉTODOS: Incluídos pacientes com critérios pré-definidos de angina instável, infarto sem supradesnivelamento do ST ou infarto com supradesnivelamento do ST. Sangramento maior durante o internamento foi definido de acordo com os tipos 3 ou 5 da Classificação Universal de Sangramento. Regressão logística e análise da sequência de eventos foram utilizadas para avaliar a associação entre sangramento e óbito. RESULTADOS: Dentre 455 pacientes estudados, 29 desenvolveram sangramento maior (6,4%; 95%IC = 4,3-9,0%. Esses indivíduos apresentaram mortalidade hospitalar de 21%, comparados a 5,6% nos pacientes sem sangramento (RR = 4,0; 95%IC = 1,8-9,1; P = 0,001. Após ajuste para escore de propensão, sangramento maior permaneceu preditor de óbito hospitalar (OR = 3,34; 95%IC = 1,2-9,5; P = 0,02. Houve 6 óbitos dentre 29 pacientes que sangraram. No entanto, análise detalhada da sequência de eventos demonstrou relação causal em apenas um caso. CONCLUSÃO: (1 Sangramento maior é preditor independente de óbito hospitalar em SCA; (2 O papel do sangramento como marcador de risco predomina sobre seu papel de fator de risco para óbito. Essa conclusão deve ser vista como geradora de hipótese a ser confirmada por estudos de maior tamanho amostral. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0BACKGROUND: Hemorrhagic events in Acute Coronary Syndromes (ACS have been independently associated with death in international multicenter registries. However, that

  16. 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...

  17. How to be causal

    CERN Document Server

    Kinsler, Paul

    2011-01-01

    I explain a simple definition of causality in widespread use, and indicate how it links to the Kramers Kronig relations. The specification of causality in terms of temporal differential eqations then shows us the way to write down dynamical models so that their causal nature in the sense used here should be obvious to all. In particular, I apply this reasoning to Maxwell's equations, which is an instructive example since their casual properties are sometimes debated.

  18. 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.

  19. 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...

  20. 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.

  1. Community health agent: a literature review Agente comunitario de salud: una revisión de literatura O agente comunitário de saúde: uma revisão da literatura

    Directory of Open Access Journals (Sweden)

    Ana Cláudia Garabeli Cavalli Kluthcovsky

    2006-12-01

    Full Text Available Study of the review literature regarding brazilian Community Health Agent. The methodology was descriptive and exploratory study, using the LILACS database (1982 to march/2005 and MEDLINE (1966 to 2005. The analysis resulted 153 publications, from which 97 had been excluded. About type of production, of the 56 references (100%, 53,6% were books, 32,1% periodic articles, 7,1% Master's Theses and remains 7,2%, doctoral dissertations and specialization monographs. It was observed that 59% of the references had been enclosed in the database in 2000. Considering only periodic articles, specialization monographs, Master's Theses and doctoral dissertations, an amount of 26 studies, the experimental design predominated (73%, being the objectives most frequent: characterization of the agents and their functions, process work and results. The data suggest increasing interest on the subject, however, these workers still consist a population little studied.Estudio de literatura de revisión sobre Agente Comunitario de Salud brasileiro. La metodología era estudio descriptivo y exploratório, en base de datos LILACS (1982 a 2005 y MEDLINE (1966 a 2005. El análisis resultó 153 publicaciones, 97 excluidos. De las 56 referencias (100%, 53,6% eran los libros, 32,1% artículos de periódicos, 7,1% eran disertaciones de maestría y del resto 7,2%, las tesis de doctorado y monografías de especialización. El 59% de las referencias habían sido incluidos en la base de datos en 2000. Considerando los artículos periódicos, las monografías de especialización, dissertaciones de maestría y tesis de doctorado (26 estudios, el diseño experimental predominó (73%, siendo los objetivos más frecuentes: caracterización de los agentes y de sus funciones, evaluaciónes del proceso y de los resultados del trabajo. Los datos sugieren interés de aumento en el tema, estos trabajadores todavía consisten una población poco estudiada.Este é um estudo de revisão da

  2. As relações entre saúde e trabalho dos agentes de combate às endemias da Funasa: a perspectiva dos trabalhadores The relationship between health and work of FUNASA's endemic diseases combat agents

    OpenAIRE

    Hilka Flavia Saldanha Guida; Kátia Reis de Souza; Maria Blandina Marques dos Santos; Solange Maria Carvalho Lima da Silva; Valéria Pereira Silva

    2012-01-01

    O presente artigo analisa as relações entre saúde e trabalho dos agentes de combate às endemias (ACEs) da Fundação Nacional de Saúde (Funasa), lotados no município de Nova Iguaçu-RJ, que foram reintegrados ao quadro da administração pública após terem sido dispensados. Os objetivos principais deste estudo foram compreender a história da luta destes trabalhadores por reconhecimento social e justiça, cujo desfecho foi a readmissão ao trabalho, bem como conhecer os efeitos adversos na saúde em r...

  3. A Universidade Federal da Fronteira Sul como agente promotor da agroecologia no território Cantuquiriguaçu-PR/ Brasil

    OpenAIRE

    Rauber, Ana Claudia; Leandrini, Josimeire A.; Franzener, Gilmar

    2015-01-01

    A Universidade Federal da Fronteira Sul (UFFS) com campi nos três estados da região Sul do Brasil foi uma conquista dos movimentos sociais. Um dos campus está localizado no Território da Cidadania Cantuquiriguaçu, município de Laranjeiras do Sul-PR. Esta experiência tem como objetivo demonstrar como a universidade contribuiu com a valorização do modo de ser camponês na região, e com a promoção e disseminação da Agroecologia no território, através do aumento da agrobiodiversidade e do resgate ...

  4. Causal Newton Gravity Law

    CERN Document Server

    Zinoviev, Yury M

    2012-01-01

    The equations of the relativistic causal Newton gravity law for the planets of the solar system are studied in the approximation when the Sun rests at the coordinates origin and the planets do not iteract between each other.

  5. Causal spin foams

    CERN Document Server

    Immirzi, Giorgio

    2016-01-01

    I discuss how to impose causality on spin-foam models, separating forward and backward propagation, turning a given triangulation to a 'causal set', and giving asymptotically the exponential of the Regge action, not a cosine. I show the equivalence of the prescriptions which have been proposed to achieve this. Essential to the argument is the closure condition for the 4-simplices, all made of space-like tetrahedra.

  6. 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...

  7. 柑桔黄龙病的鉴定和柯赫氏定理%"Candidatus Liberibacter Species": Without Koch's Postulates Completed, Can the Bacterium be Considered as the Causal Agent of Citrus Huanglongbing (Yellow Shoot Disease) ?

    Institute of Scientific and Technical Information of China (English)

    Chen J; Deng X; Civerolo E L; Lee R F; Jones J B; Zhou C; Hartung J S; Manjunath K L; Brlansky R H

    2011-01-01

    Huanglongbing (HLB, yellow shoot disease) has been a destructive disease of citrus around the world for over a century, yet the etiology of the disease has not been definitively established. Based mainly on assays for 16S rRNA gene sequences, fastidious bacteria known as "Candidatus Liberibacter species" have been .ssociated with HLB. We are concerned that some current literature frequendy refers to "Ca. Liberibacter spp." as the causal or etiological agent of HLB. However, Koch' s postulates, either sensu stricto or modified, have not yet been completely fulfilled to establish that "Ca. Liberibacter spp." are the cause of HLB.Direct pathological interactions between the bacteria and citrus host have not been conclusively documented.We suggest there is a need for the literature to be precise on this point until the etiology of HLB is firmly established.%黄龙(梢)病被认为是世界柑橘生产上的毁灭性病害已超过一个世纪,但该病害的病原学至今还没有清晰地建立起来.根据16S rRNA基因序列分析,一组被称为"Candidatus Liberibacter species"的难培养细菌被认为与黄龙病相关.然而,要确定"Ca.Liberibacter spp."是黄龙病病原的柯赫氏定理并没有真正完成.令我们担忧的是,近年来有些文献频频指出"Ca.Liberibacter spp."是黄龙病的病原,其实该细菌与柑橘寄主的直接病理反应还没有完全确定.我们建议,在黄龙病病原学清楚之前,文献报道在这方面需要有准确的阐述.

  8. Blendas de poliamida 6/elastômero: propriedades e influência da adição de agente compatibilizante

    Directory of Open Access Journals (Sweden)

    Barra Guilherme M. O.

    2003-01-01

    Full Text Available Neste trabalho foram estudadas as propriedades micro e macroscópicas de misturas físicas binárias de poliamida 6 [PA6] com copolímero poli(etileno-co-propileno-co-dieno [EPDM] e em presença de pequenas quantidades de EPDM ou EPM enxertados com anidrido maleico, atuando como agentes compatibilizantes. Os componentes puros (poliamida 6 e EPDM e as blendas poliméricas em diferentes composições foram analisados por calorimetria diferencial de varredura (DSC e espectroscopia de infravermelho (FTIR. Os resultados indicaram a imiscibilidade dos componentes da mistura em toda a faixa de composição estudada. A utilização das técnicas de análise elementar, microscopia eletrônica de varredura e propriedades mecânicas permitiu avaliar a homogeneidade da mistura, a redução do tamanho dos domínios do elastômero e o aumento da força de impacto da matriz de PA6 com a adição do agente compatibilizante à mistura binária de PA6/EPDM.

  9. Desafios e perspectivas da Educação Popular em Saúde na constituição da práxis do Agente Comunitário de Saúde

    Directory of Open Access Journals (Sweden)

    Vera Joana Bornstein

    2014-12-01

    Full Text Available O estudo problematiza as práticas do Agente Comunitário de Saúde no Brasil, especialmente no que se refere ao seu exercício como educador no contexto das políticas de saúde e de sua atuação profissional. Para a sua construção, considerou-se a experiência das autoras na formação técnica de Agentes Comunitários de Saúde na EPSJV/Fiocruz e a realização de revisão de literatura sobre o tema. Os resultados encontrados indicam possíveis contradições entre as prescrições legais do trabalho do ACS, as expectativas dos serviços em relação à ação desse trabalhador e a possibilidade de ele se constituir como um educador popular. Por fim, apresenta perspectivas e desafios da Educação Popular em Saúde para as mudanças necessárias e possíveis nas práticas dos ACSs, em direção à efetivação da integralidade, da participação popular e do diálogo com o saber popular no âmbito da Atenção Básica.

  10. Ação de produtos químicos in vitro e in vivo sobre Clavibacter michiganensis subsp. michiganensis, agente causal do cancro bacteriano do tomateiro In vitro and in vivo action of chemicals on Clavibacter michiganensis subsp. michiganensis, causal agent of the bacterial canker of tomato

    Directory of Open Access Journals (Sweden)

    Gustavo de Faria Theodoro

    2000-09-01

    Full Text Available O presente trabalho teve como objetivo avaliar a sensibilidade in vitro e in vivo de um isolado de Clavibacter michiganensis subsp. michiganensis (Cmm aos produtos cloridrato de kasugamicina, fulusulfamide e oxitetraciclina. Para o teste in vitro, foram avaliados os halos de inibição formados ao redor de discos de papel de filtro umedecidos com os produtos, nas concentrações de 0, 1, 10, 100 e 1000 mig mL-1, 24 h após a instalação do ensaio. Quanto à avaliação dos produtos in vivo, dois ensaios foram instalados sob condições de casa-de-vegetação, com plantas de tomateiro cultivar Ângela Hiper, através da inoculação das plantas por dois métodos: pulverização foliar e ferimento no caule. Nos dois ensaios, as plantas foram pulverizadas com os produtos cloridrato de kasugamicina a 0,06 mL L-1, fulusulfamide a 0,025, 0,05 e 0,075 mL L-1 e oxitetraciclina a 0,40 g L-1, duas vezes antes e duas vezes após a inoculação, em intervalos médios de 5-7 dias. Foram avaliados a incidência de folíolos doentes (inoculação foliar e a severidade dos sintomas nas plantas inoculadas por ferimento no caule. Verificou-se que o isolado de Cmm foi sensível in vitro ao cloridrato de kasugamicina, ao fulusulfamide e à oxitetraciclina, respectivamente a partir das concentrações de 1000, 100 e 10 mig mL-1. Com relação aos ensaios in vivo, apenas oxitetraciclina propiciou menor incidência de folíolos doentes nas plantas inoculadas através de pulverização foliar; nenhum produto teve êxito em controlar a doença nas plantas inoculadas por ferimento no caule. O fulusulfamide, em todas as concentrações, foi fitotóxico aos folíolos das plantas de tomateiro.An experiment was carried out to evaluate the in vivo and in vitro sensibility of a Clavibacter michiganensis subsp. michiganensis isolate (Cmm to the products kasugamicyn cloridrate, fulusulfamide and oxytetracicline. In the in vitro tests, the inhibition formed around the discs of

  11. 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...

  12. 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...

  13. 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.

  14. Complementarity, causality, and explanation

    CERN Document Server

    Losee, John

    2013-01-01

    Prior to the work of Niels Bohr, discussions on the relationship of cause and effect presupposed that successful causal attribution implies explanation. The success of quantum theory challenged this presupposition. In this succinct review of the history of these discussions, John Losee presents the philosophical background of debates over the cause-effect relation. He reviews the positions of Aristotle, René Descartes, Isaac Newton, David Hume, Immanuel Kant, and John Stuart Mill. He shows how nineteenth-century theories in physics and chemistry were informed by a dominant theory of causality

  15. Causal premise semantics.

    Science.gov (United States)

    Kaufmann, Stefan

    2013-08-01

    The rise of causality and the attendant graph-theoretic modeling tools in the study of counterfactual reasoning has had resounding effects in many areas of cognitive science, but it has thus far not permeated the mainstream in linguistic theory to a comparable degree. In this study I show that a version of the predominant framework for the formal semantic analysis of conditionals, Kratzer-style premise semantics, allows for a straightforward implementation of the crucial ideas and insights of Pearl-style causal networks. I spell out the details of such an implementation, focusing especially on the notions of intervention on a network and backtracking interpretations of counterfactuals.

  16. Understanding Causal Coherence Relations

    NARCIS (Netherlands)

    Mulder, G.

    2008-01-01

    The research reported in this dissertation focuses on the cognitive processes and representations involved in understanding causal coherence relations in text. Coherence relations are the meaning relations between the information units in the text, such as Cause-Consequence. These relations can be m

  17. Análise da rugosidade superficial de materiais restauradores estéticos: efeito de agentes clareadores e tempo = Analysis of roughness surface of aesthetic restoring materials: effect of bleaching agentes and time

    Directory of Open Access Journals (Sweden)

    Pozzobon, Roselaine Terezinha

    2005-01-01

    Full Text Available Este estudo in vitro avaliou o efeito de agentes clareadores na rugosidade superficial (Ra de materiais restauradores estéticos, com o passar do tempo. Foram utilizadas duas resinas compostas, Z100 (M1 e Silux-Plus (M2, um compômero, Dyract (M3 e um ionômero de vidro modificado por resina, Vitremer (M4, que foram expostos a dois agentes clareadores: Opalescence (C1, peróxido de carbamida 10%, e Hi-Lite (C2, peróxido de hidrogênio 35% e como meio de imersão foi utilizada saliva artificial (Co. Foram confeccionados 120 corpos de prova, sendo a Ra avaliada após 1 hora de confecção; e antes da imersão em saliva artificial (T0, após 1dia (T1, 7 (T2, 15 (T3 e 30 (T4 dias de exposição aos agentes clareadores. No grupo controle, os corpos-de-prova ficaram somente imersos em saliva artificial. Após análise estatística de variância ANOVA (a = 5%, teste de Tukey, e método da decomposição da soma de quadrados, foi possível concluir que: 1 – a Ra dos materiais restauradores estéticos, de forma geral, alterou-se após exposição aos diferentes agentes clareadores e ao longo do tempo; 2 – em função do material restaurador, M2 apresentou a maior média de Ra, seguido em ordem decrescente por M4, M3 e M1; 3 – C1 e C2 exerceram ação sobre a superfície dos materiais restauradores aumentando a Ra para todos os materiais avaliados, principalmente em M2 e M4; 4 – em função do fator tempo, observou-se influência estatisticamente significativa sobre a Ra, pois quanto maior o tempo de exposição ao agente clareador, maiores os valores médios de Ra

  18. O projeto cultural de PLE como agente da interculturalidade num contexto de não-­imersão

    Directory of Open Access Journals (Sweden)

    Eliete Farneda Sampaio

    2015-12-01

    Full Text Available O objetivo desta pesquisa foi investigar os aspectos interculturais no processo de ensino/ aprendizagem de Português Língua Estrangeira, no contexto de não-imersão. Através da introdução de tarefas comunicativas e da abordagem comunicativa procurou-­se determinar o que é cultura (Mendes, 2010 e qual cultura deve ser ensinada durante o processo de ensino/ aprendizagem de uma língua estrangeira (Khramsch, 2013, entre outros. Os resultados nos mostraram, a percepção da interculturalidade tida pelo aprendente durante a realização do projeto cultural, relacionando a sua cultura com a cultura do outro e minimizando as ideias esteriotipadas anteriormente tidas sobre a cultura da língua-­alvo.

  19. ATUAÇÃO DOS AGENTES DE COMUNICAÇÃO DA INDÚSTRIA FONOGRÁFICA NA REDE SOCIAL FACEBOOK: UM ESTUDO DE CASO DA GLOBAL RECORDS

    Directory of Open Access Journals (Sweden)

    Holbein Oliveira de Menezes Filho

    2015-12-01

    Full Text Available Esta pesquisa teve como objetivo investigar as influências dos agentes de comunicação da indústria fonográfica atuantes no Facebook no estimulo ao consumo do produto fonográfico, identificando os efeitos das estratégias de comunicação nesse ambiente e sua influência na construção de significados e consumo. Baseada em um estudo de caso de abordagem qualitativa, a coleta de dados foram utilizados entrevistas semiestruturadas, conduzidas individualmente face a face com os sujeitos selecionados. O publico alvo, ficou restrito aos moradores das Zonas Sul e Oeste da cidade do Rio de Janeiro, na faixa etária de 20 a 50 anos. A análise dos dados utilizou-se Gollner e Goulart (2013, adotando a análise do conteúdo e reagrupamento das mensagens em categorias temáticas, visando buscar elementos que expressem os conceitos: Institucional; Mercadológica e Relacional. Como conclusão ficou a importância da divulgação do produto fonográfico no Facebook, devido em parte ao enfraquecimento dos efeitos na criação de significados dos produtos por meio da divulgação na imprensa, no rádio e na TV, demonstrando o potencial desse canal, que não vem sendo bem explorado.

  20. COM QUE ROUPA EU VOU? O JORNALISTA ESPECIALIZADO COMO FORMADOR DE OPINIÃO E AGENTE DE CONSAGRAÇÃO NO CAMPO DA MODA

    OpenAIRE

    Virgínia Todeschini Borges

    2014-01-01

    Este artigo examina o papel do jornalista moda como formador de opinião e como um dos agentes de consagração no campo da moda. Tendo como base pesquisa bibliográfica e realização de entrevistas qualitativas como metodologia de coleta de dados, procuramos responder as seguintes perguntas: Quem dita a moda na atualidade? Como é o trabalho de um jornalista de moda? Qual a importância destes formadores de opinião no lançamento de tendências de moda?

  1. Revisiting Causality in Markov Chains

    OpenAIRE

    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 capt...

  2. Context, causality, and appreciation.

    Science.gov (United States)

    Ross, Stephanie

    2013-04-01

    I applaud and elaborate on the contextualism at the heart of Bullot & Reber's (B&R's) theory, challenge two aspects of the appreciative structure they posit (the causal reasoning that allegedly underlies the design stance and the segregation of the component stages), suggest that expert and novice appreciators operate differently, and question the degree to which B&R's final theory is open to empirical investigation. PMID:23507111

  3. Addition of a hypoxic cell selective cytotoxic agent (mitomycin C or porfiromycin) to Fluosol-DA/carbogen/radiation

    Energy Technology Data Exchange (ETDEWEB)

    Holden, S.A.; Teicher, B.A. (Dana-Farber Cancer Institute, Boston (USA)); Herman, T.S. (Dana-Farber Cancer Institute, Boston (USA) Joint Center for Radiation Therapy, Boston (USA))

    1990-05-01

    In an effort to develop effictive combination treatments for use with radiation against solid tumors, the cytotoxic effects of the addition of mitomycin C or porfiromycin on treatment with Fluosol-DA/carbogen breathing and radiation in the FSaIIC tumor system were studied. In vitro mitomycin C and porfiromycin were both preferentially cytotoxic toward hypoxic FSaIIC cells. After in vivo exposure, however, the cytotoxicity of mitomycin C toward single cell tumor suspensions obtained from whole tumors was exponential over the dose range studied, but for porfiromycin a plateau in cell killing was observed. With Fluosol-DA/carbogen breathing and single dose radiaiton, addition of either mitomycin C or porfiromycin increased the tumor cell kill achieved at 5 Gy by approximately 1.2 and 1.0 logs, respectively. Less effect was seen with addition of the drugs at the 10 and 15 Gy radiation doses. In tumor growth delay experiments, the addition of either mitomycin C or porfiromycin to Fluosol-DA/carbogen breathing and radiation resulted in primarily an additive increase in tumor growth delay. The survival of Hoechst 33342 dye-selected tumor cell subpopulations indicated that Fluosol-DA/carbogen breathing increased the cytotoxicity of radiation (10 Gy) more in the bright cell subpopulation (4-fold) than in the dim cell subpopulation (2-fold) resulting in an overall 4-fold sparing of the dim subpopulation. Mitomycin C and porfiromycin were both more toxic toward the dim cell subpopulations. Addition of mitomycin C or porfiromycin to Fluosol-DA/carbogen breathing and radiation (10 Gy) resulted in a primarily additive effect of the drugs and radiation killing in both tumor cell subpopulations. Thus, with mitomycin C/Fluosol-DA/carbogen and radiation there was a 2-fold sparing of dim cells and with profiromycin in the combined treatment a 1.6-fold sparing of the dim cell population. (Abstract Truncated)

  4. 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...

  5. 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

  6. Effects of Jinggangmycin on the growth and development of Rhizoctonia solani Kühn causal agent of rice sheath blight%井冈霉素对水稻纹枯病菌生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    杨媚; 杨迎青; 李明海; 舒灿伟; 周而勋

    2012-01-01

    以水稻纹枯病菌(Rhizoctonia solani Kühn)强致病菌株GD-118为供试菌株,在室内观察了井冈霉素(Jinggangmycin)对其生长发育的影响.结果表明:井冈霉素对水稻纹枯病菌的毒力回归方程为y=3.3603+1.3204x,相关系数r=0.9626,理论抑制菌丝生长的EC5o为70.2μg/mL,EC95为6341.5μg/mL.与不加井冈霉素的空白对照相比,用井冈霉素处理后水稻纹枯病菌的菌落边缘明显凹凸不平,边缘菌丝更密集、颜色加深,并且随着井冈霉素处理浓度的增加,菌丝的干质量逐渐降低,但菌落表面菌丝的密集程度有所增加、颜色更深;空白对照的菌核呈颗粒状、褐色,散生于菌落表面,边缘较多而中间较少;用井冈霉素处理后的菌核多数为粉状、浅褐色,部分菌核会连在一起呈块状,分布在菌落外围呈明显的双环形,具不规则的凹凸型菌落边缘,并且随着井冈霉素处理浓度的增加,菌核的干质量有所增加,菌核出现时间比空白对照提前约24 h.另外,随着井冈霉素处理浓度的增加,水稻纹枯病菌的菌丝细胞核平均数目和分布范围均有不正常增多的趋势.%The effects of Jinggangmycin on the growth and development of Rhizoctonia solani K(u)hn causal agent of rice sheath blight, were investigated by using a virulent isolate GD-118 of R. Solani as the test isolate. The results showed that the regression equation for Jinggangmycin toxicity to R. Solani was: y=3. 360 3+1. 320 4χ, correlation coefficient r=0. 962 6,the EC50 for theoretical inhibition of my-celial growth was 70. 2 μg/mL, and the EC95 was 6 341. 5 μg/mL. In regarding to cultural characteristics and mycelial growth,compared with blank control (without Jinggangmycin), the colonies of Jinggangmycin treatments had relatively obvious characteristics of uneven edges with more dense mycelia and darkened colour in the plate; with the increase of Jinggangmycin concentrations, the dry weight of mycelia decreased, but

  7. Electrochemical and calorimetric investigation of interaction of novel biscationic anticancer agents with DNA; Investigacao eletroquimica e calorimetrica da interacao de novos agentes antitumorais biscationicos com DNA

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Lauris Lucia da; Donnici, Claudio Luis; Lopes, Julio Cesar Dias, E-mail: cdonnici@terra.com.br [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Quimica; Goulart, Marilia Oliveira Fonseca; Abreu, Fabiane Caxico de; Paula, Francine Santos de [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Campus A.C. Simoes. Inst. de Quimica e Biotecnologia; Bravo, Carlos E. Salas; Santoro, Marcelo Matos [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Dept. de Bioquimica e Imunologia; Denadai, Angelo Marcio Leite [Centro Federal de Educacao Tecnologica, Timoteo, MG (Brazil). Campus VII; Santos, Alexandre Martins Costa [Universidade Federal do Espirito Santo, Vitoria, ES (Brazil). Dept. de Ciencias Fisiologicas; Montanari, Carlos Alberto [Universidade de Sao Paulo, Sao Carlos, SP (Brazil). Inst. de Quimica

    2012-07-01

    Biscationic amidines bind in the DNA minor groove and present biological activity against a range of infectious diseases. Two new biscationic compounds (bis-{alpha}-{omega}-S-thioureido, amino and sulfide analogues) were synthesized in good yields and fully characterized, and their interaction with DNA was also investigated. Isothermal titration calorimetry (ITC) was used to measure the thermodynamic properties of binding interactions between DNA and these ligands. A double stranded calf thymus DNA immobilized on an electrode surface was used to study the possible DNA-interacting abilities of these compounds towards dsDNA in situ. A remarkable interaction of these compounds with DNA was demonstrated and their potential application as anticancer agents was furthered. (author)

  8. As relações entre saúde e trabalho dos agentes de combate às endemias da Funasa: a perspectiva dos trabalhadores The relationship between health and work of FUNASA's endemic diseases combat agents

    Directory of Open Access Journals (Sweden)

    Hilka Flavia Saldanha Guida

    2012-12-01

    Full Text Available O presente artigo analisa as relações entre saúde e trabalho dos agentes de combate às endemias (ACEs da Fundação Nacional de Saúde (Funasa, lotados no município de Nova Iguaçu-RJ, que foram reintegrados ao quadro da administração pública após terem sido dispensados. Os objetivos principais deste estudo foram compreender a história da luta destes trabalhadores por reconhecimento social e justiça, cujo desfecho foi a readmissão ao trabalho, bem como conhecer os efeitos adversos na saúde em razão das condições da atividade de combate a endemias. Adotou-se como base metodológica os estudos participativos e, complementarmente, o enfoque da educação popular, realizando grupos de discussão com os trabalhadores. Trata-se, por conseguinte, de uma pesquisa de cunho pedagógico, na qual o diálogo é a relação fundamental. Dos temas identificados nos grupos de discussão obteve-se um repertório de problemas e questões que evidenciaram as más condições de trabalho e a desregulamentação de políticas de saúde voltada para os trabalhadores. Os próprios trabalhadores reconhecem a precarização de seu trabalho, conferindo grande responsabilidade à interferência da política. Referiram-se ainda a um período de incertezas, sofrido pela indefinição de responsabilidades entre os níveis de governo, durante o período de descentralização político-administrativa, e seus efeitos negativos na saúde. Mencionaram o possível aspecto de toxicidade dos inseticidas e os seus riscos de contaminação. Foram sinalizadas sugestões que podem ser adotadas, de modo a propiciar melhores condições de trabalho e de saúde.This article analyses the relationship between health and work of the Agentes de Combate às Endemias (ACE - endemic diseases combat agents of Fundação Nacional de Saúde (FUNASA who work in the city of Nova Iguaçu (Southeastern Brazil and who were readmitted after being dismissed. It aims to give visibility to

  9. 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,...

  10. Fusarium oxysporum strains as biocontrol agents against Fusarium wilt: effects on soil microbial biomass and activity Linhagens de Fusarium oxysporum como agentes de biocontrole da murcha-de-Fusarium: efeitos na biomassa e atividade microbiana do solo

    Directory of Open Access Journals (Sweden)

    Raquel Ghini

    2000-01-01

    Full Text Available Before planning the large-scale use of nonpathogenic strains of Fusarium oxysporum as biocontrol agents of Fusarium wilt, their behaviour and potential impact on soil ecosystems should be carefully studied as part of risk assessment. The aim of this work was to evaluate the effects of antagonistic F. oxysporum strains, genetically manipulated (T26/6 or not (233/1, on soil microbial biomass and activity. The effects were evaluated, in North-western Italy, in two soils from different sites at Albenga, one natural and the other previously solarized, and in a third soil obtained from a 10-year-old poplar stand (Popolus sp., near Carignano. There were no detectable effects on ATP, fluorescein diacetate hydrolysis, and biomass P that could be attributed to the introduction of the antagonists. A transient increase of carbon dioxide evolution and biomass C was observed in response to the added inoculum. Although the results showed only some transient alterations, further studies are required to evaluate effects on specific microorganism populations.Antes do uso em larga escala de linhagens não-patogênicas de Fusarium oxysporum como agentes de biocontrole da murcha-de-Fusarium, o seu comportamento e seus impactos potenciais no solo devem ser estudados como parte da avaliação de riscos. O objetivo do presente trabalho foi avaliar os efeitos de linhagens antagonistas de F. oxysporum, geneticamente manipuladas (T26/6 ou não (233/1, na biomassa e atividade microbiana do solo. Os efeitos foram avaliados no noroeste da Itália em dois solos de Albenga, sendo um natural e outro previamente solarizado, e em um terceiro solo obtido numa plantação de 10 anos de Popolus sp., em Carignano. Não foram observados efeitos significativos na quantidade de ATP, hidrólise de diacetato de fluoresceina e biomassa P, após a introdução dos antagonistas. Um aumento transitório foi observado na evolução de dióxido de carbono e no carbono da biomassa em resposta

  11. Addition of a hypoxic cell selective cytotoxic agent (mitomycin C or porfiromycin) to Fluosol-DA/carbogen/radiation.

    Science.gov (United States)

    Holden, S A; Herman, T S; Teicher, B A

    1990-05-01

    In an effort to develop effective combination treatments for use with radiation against solid tumors, the cytotoxic effects of the addition of mitomycin C or porfiromycin on treatment with Fluosol-DA/carbogen (95% O2/5% CO2) breathing and radiation in the FSaIIC tumor system were studied. In vitro mitomycin C and porfiromycin were both preferentially cytotoxic toward hypoxic FSaIIC cells. After in vivo exposure, however, the cytotoxicity of mitomycin C toward single cell tumor suspensions obtained from whole tumors was exponential over the dose range studied, but for porfiromycin a plateau in cell killing was observed. With Fluosol-DA/carbogen breathing and single dose radiation, addition of either mitomycin C or porfiromycin increased the tumor cell kill achieved at 5 Gy by approximately 1.2 and 1.0 logs, respectively. Less effect was seen with addition of the drugs at the 10 and 15 Gy radiation doses. In tumor growth delay experiments, the addition of either mitomycin C or porfiromycin to Fluosol-DA/carbogen breathing and radiation resulted in primarily an additive increase in tumor growth delay. The survival of Hoechst 33342 dye-selected tumor cell subpopulations indicated that Fluosol-DA/carbogen breathing increased the cytotoxicity of radiation (10 Gy) more in the bright cell subpopulation (4-fold) than in the dim cell subpopulation (2-fold) resulting in an overall 4-fold sparing of the dim subpopulation. Mitomycin C and porfiromycin were both more toxic toward the dim cell subpopulations. Addition of mitomycin C or porfiromycin to Fluosol-DA/carbogen breathing and radiation (10 Gy) resulted in a primarily additive effect of the drugs and radiation killing in both tumor cell subpopulations. Thus, with mitomycin C/Fluosol-DA/carbogen and radiation there was a 2-fold sparing of dim cells and with porfiromycin in the combined treatment a 1.6-fold sparing of the dim cell population. Our results indicate that treatment strategies directed against both oxic and

  12. Agentes dopaminérgicos e o tratamento da disfunção erétil

    Directory of Open Access Journals (Sweden)

    Neves Gilda

    2004-01-01

    Full Text Available The understanding of the scientific basis of the erectile function expanded rapidly the range of therapies for treating erectile dysfunction in recent years. This article reviews the role of dopamine on the erection mechanisms and its importance for new pro-erectile drug design. The ability of dopaminergic agents to elicit penile erection has been described since 1975 and successively confirmed by numerous studies. The development of apomorphine SL (dopaminergic non selective agonist to enhance erectile function represents a new pharmacological approach to the management of erectile dysfunction using CNS drugs. The search for selective D4 dopaminergic agents is being explored by some research groups and pharmaceutical companies.

  13. Agente Comunitário de Saúde no controle da tuberculose na Atenção Primária à Saúde Agente Comunitario de Salud en el control de la tuberculosis en la Atención Primaria a la Salud The Community Health Agent in the control of tuberculosis in Primary Health Care

    OpenAIRE

    Juliane de Almeida Crispim; Beatriz Estuque Scatolin; Laís Mara Caetano da Silva; Ione Carvalho Pinto; Pedro Fredemir Palha; Ricardo Alexandre Arcêncio

    2012-01-01

    OBJETIVO: Avaliar o desempenho do Agente Comunitário de Saúde (ACS) no controle da tuberculose (TB) em áreas assistidas pela Estratégia Saúde da Família (ESF), sendo estabelecida uma análise comparativa com os ACSs inscritos nas Unidades Básicas de Saúde (UBS) tradicionais. MÉTODOS: Estudo transversal, realizado em um município prioritário para o controle da TB no Estado de São Paulo, com uma amostra mínima de 108 ACSs das ESFs e das UBSs. Para a coleta de dados, utilizou-se um instrumento el...

  14. Entropy of Causal Horizons

    CERN Document Server

    Howard, Eric M

    2016-01-01

    We analyze spacetimes with horizons and study the thermodynamic aspects of causal horizons, suggesting that the resemblance between gravitational and thermodynamic systems has a deeper quantum mechanical origin. We find that the observer dependence of such horizons is a direct consequence of associating a temperature and entropy to a spacetime. The geometrical picture of a horizon acting as a one-way membrane for information flow can be accepted as a natural interpretation of assigning a quantum field theory to a spacetime with boundary, ultimately leading to a close connection with thermodynamics.

  15. 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

  16. 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 ...

  17. Agente Comunitário de Saúde: um novo ator no cenário da saúde do Brasil Community Health Agent: a new actor in the Brazilian health scenario

    Directory of Open Access Journals (Sweden)

    Andréa Sabino Filgueiras

    2011-01-01

    Full Text Available O Programa de Agentes Comunitários de Saúde (PACS foi introduzido no Brasil em 1991 como uma tática para o desenvolvimento de atividades relacionadas à prevenção de doenças e educação em saúde. Em 1994, o Ministério da Saúde propôs o Programa de Saúde da Família (PSF como estratégia de reestruturação da atenção à saúde. Essas propostas introduzem, no cenário da saúde, um novo ator, o Agente Comunitário de Saúde (ACS, desempenhando importante papel na atenção básica, ao agir como um elo entre famílias, usuários e serviço de saúde. O estudo toma como objeto o trabalho desenvolvido pelos ACS em uma unidade do PSF do município de Volta Redonda-RJ. Tem como objetivo discutir os aspectos facilitadores e limitantes das atividades designadas aos ACS. Trata-se de uma pesquisa do tipo descritiva, com abordagem qualitativa. A análise de dados se deu por categorias analíticas, que emergiram a partir dos dados encontrados nas entrevistas. Após a apreciação dos dados, pôde-se constatar que os ACS do PSF de Volta Redonda ainda não recebem formação destinada à execução de suas atividades e que consideram a experiência prática como o principal motor para o desempenho delas. O trabalho em equipe é reconhecido como espaço de circulação de saberes científicos e o saber popular como mediador entre a equipe e a população. Os ACS têm como eixo de trabalho a visita domiciliar, focada principalmente na doença.The Community Health Agents Program (PACS was created in 1991 as a strategy to implement the SUS, developing activities related to prevention and health education. In 1994, the Health Ministry proposed the Family Health Program (PSF as a strategy for restructuring the dominant care model. With the emergence of these two programs, there is the emergence of a new actor in the health scenario, the Community Health Agent (ACS. This actor plays an important role in basic care, acting as a link between families

  18. O direito à vida no contexto do aborto e da pesquisa com células-tronco embrionárias: disputas de agentes e valores religiosos em um estado laico

    Directory of Open Access Journals (Sweden)

    Naara Luna

    2013-01-01

    Full Text Available O artigo aborda o debate público sobre o direito à vida no contexto da autorização da pesquisa com células-tronco embrionárias e no debate sobre o aborto, enfocando a participação de atores religiosos e seus valores. Serão examinados o debate legislativo e judiciário da Lei de Biossegurança e a audiência pública da ADPF 54, referente à antecipação de parto de anencéfalo. Esta pesquisa documental analisa a transcrição da audiência pública da ADPF 54, e os registros do processo legislativo no Congresso Nacional e da ADI 3510 no Supremo Tribunal Federal. Os resultados revelam, além da centralidade do argumento do valor da vida, a diversidade na atuação dos agentes religiosos, com hegemonia da Igreja Católica e a emergência de evangélicos e espíritas.

  19. 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.

  20. 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.

  1. 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

  2. Experimental test of nonlocal causality

    OpenAIRE

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

    2016-01-01

    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 fro...

  3. Causal evolution of wave packets

    CERN Document Server

    Eckstein, Michał

    2016-01-01

    Drawing from the optimal transport theory adapted to the relativistic setting we formulate the principle of a causal flow of probability and apply it in the wave packet formalism. We demonstrate that whereas the Dirac system is causal, the relativistic-Schr\\"odinger Hamiltonian impels a superluminal evolution of probabilities. We quantify the causality breakdown in the latter system and argue that, in contrast to the popular viewpoint, it is not related to the localisation properties of the states.

  4. 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...

  5. 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.

  6. O contexto da formação dos agentes comunitários de saúde no Brasil

    Directory of Open Access Journals (Sweden)

    Daniela França de Barros

    2010-01-01

    Full Text Available Este estudio tuvo como objetivo identificar y describir el proceso histórico de la formación profesional de los agentes comunitarios de salud, mediante el análisis de documentos relativos a la formación técnica en salud. Es una investigación documental realizada en documentos normativos e instrumentales en los registros administrativos y de gestión del Departamento de Atención Primaria, con investigación bibliográfica en las bases de datos Medline y LILACS, de publicaciones orientadas a la política de formación profesional, en el período de 1986 a 2006, y de lectura con análisis temático. En respuesta a las demandas políticas y económicas, el agente comunitario de salud se convirtió en profesión en 2002. Sus funciones fueron ampliadas, motivo por el cual, en 2006 ya había en Brasil más de 200 mil profesionales trabajando según el nuevo reglamento: la Ley 11.350, que revocó la ley anterior. El agente comunitario se convirtió en un elemento importante para la promoción de cambios en el modelo asistencial y el fortalecimiento de la atención primaria en salud.

  7. 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

  8. Identifiability of causal effect for a simple causal model

    Institute of Scientific and Technical Information of China (English)

    郑忠国; 张艳艳; 童行伟

    2002-01-01

    Counterfactual model is put forward to discuss the causal inference in the directed acyclic graph and its corresponding identifiability is thus studied with the ancillary information based on conditional independence. It is shown that the assumption of ignorability can be expanded to the assumption of replaceability,under which the causal efiects are identifiable.

  9. Structural Equations and Causal Explanations: Some Challenges for Causal SEM

    Science.gov (United States)

    Markus, Keith A.

    2010-01-01

    One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

  10. 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.

  11. A atuação do agente comunitário de saúde na promoção da saúde e na prevenção de doenças

    OpenAIRE

    Maria Rizoneide Negreiros Araújo; Raquel Silva Assunção

    2004-01-01

    O artigo trata das ações desenvolvidas pelo agente comunitário de saúde - ACS no Programa de Saúde da Família de Divinópolis - MG, fazendo uma relação de tuação nos campos da Promoção da Saúde e da Prevenção de Doenças, tomando como referencial a I Conferência Internacional sobre Promoção da Saúde, realizada no Canadá, em 1986. A pesquisa de campo foi realizada com questionário, observação direta e entrevista com os ACS. De abordagem qualitativa em que as concepções e expressões dos sujeitos ...

  12. Chestnut and lemon balm based ingredients as natural preserving agents of the nutritional profile in matured "Serra da Estrela" cheese.

    Science.gov (United States)

    Carocho, Márcio; Barreira, João C M; Bento, Albino; Fernández-Ruiz, Virginia; Morales, Patricia; Ferreira, Isabel C F R

    2016-08-01

    Chestnut flowers, lemon balm plants and their decoctions were incorporated into "Serra da Estrela" cheese, to assess their potential to preserve its nutritional properties and provide new foodstuffs. The analyses were carried out after the normal ripening period of 1month and after 6months of storage. The most abundant nutrients were proteins and fats. The most abundant minerals were Ca and Na, while C16:0 and C18:1 were the main fatty acids. Saturated fatty acids were the most abundant, followed by the monounsaturated. Moisture seemed to be lower in the samples with the plants incorporated. The dried plants, when incorporated, seemed to be more efficient as preservers then the decoctions, although these better preserved the proteins. These plants can be regarded as promising natural preservers in foodstuffs cheese, given the preservation of key parameters and the slight impact on the nutritional value. PMID:26988492

  13. O trabalho no cárcere: reflexões acerca da saúde do agente penitenciário

    Directory of Open Access Journals (Sweden)

    Caroline Raquele Jaskowiak

    2015-04-01

    Full Text Available RESUMO Objetivo: conhecer as condições de trabalho de agentes penitenciários e os reflexos do exercício da atividade laboral em sua saúde. Método: pesquisa descritiva, qualitativa. Os dados foram coletados por meio de entrevista aberta com agentes de um presídio regional e submetidos a análise de conteúdo na modalidade temática. Resultados: os resultados revelaram condições de trabalho insatisfatórias por deficiência de recursos materiais e descaso do poder público com as questões inerentes à ressocialização do apenado, resultando em exposição aos riscos psicossociais, insatisfação e desgaste emocional dos trabalhadores. Conclusão: investimentos na segurança dos trabalhadores podem contribuir para a promoção de sua saúde.

  14. 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…

  15. Introduction to causal dynamical triangulations

    DEFF Research Database (Denmark)

    Görlich, Andrzej

    2013-01-01

    The method of causal dynamical triangulations is a non-perturbative and background-independent approach to quantum theory of gravity. In this review we present recent results obtained within the four dimensional model of causal dynamical triangulations. We describe the phase structure of the model...

  16. 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

  17. 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…

  18. Automatic Reasoning about Causal Events in Surveillance Video

    Directory of Open Access Journals (Sweden)

    Reid IanD

    2011-01-01

    Full Text Available We present a new method for explaining causal interactions among people in video. The input to the overall system is video in which people are low/medium resolution. We extract and maintain a set of qualitative descriptions of single-person activity using the low-level vision techniques of spatiotemporal action recognition and gaze-direction approximation. This models the input to the "sensors" of the person agent in the scene and is a general sensing strategy for a person agent in a variety of application domains. The information subsequently available to the reasoning process is deliberately limited to model what an agent would actually be able to sense. The reasoning is therefore not a classical "all-knowing" strategy but uses these "sensed" facts obtained from the agents, combined with generic domain knowledge, to generate causal explanations of interactions. We present results from urban surveillance video.

  19. Neural Correlates of Causal Power Judgments

    Directory of Open Access Journals (Sweden)

    Denise Dellarosa Cummins

    2014-12-01

    Full Text Available Causal inference is a fundamental component of cognition and perception. Probabilistic theories of causal judgment (most notably causal Bayes networks derive causal judgments using metrics that integrate contingency information. But human estimates typically diverge from these normative predictions. This is because human causal power judgments are typically strongly influenced by beliefs concerning underlying causal mechanisms, and because of the way knowledge is retrieved from human memory during the judgment process. Neuroimaging studies indicate that the brain distinguishes causal events from mere covariation, and between perceived and inferred causality. Areas involved in error prediction are also activated, implying automatic activation of possible exception cases during causal decision-making.

  20. Assessing statistical significance in causal graphs

    Directory of Open Access Journals (Sweden)

    Chindelevitch Leonid

    2012-02-01

    Full Text Available Abstract Background Causal graphs are an increasingly popular tool for the analysis of biological datasets. In particular, signed causal graphs--directed graphs whose edges additionally have a sign denoting upregulation or downregulation--can be used to model regulatory networks within a cell. Such models allow prediction of downstream effects of regulation of biological entities; conversely, they also enable inference of causative agents behind observed expression changes. However, due to their complex nature, signed causal graph models present special challenges with respect to assessing statistical significance. In this paper we frame and solve two fundamental computational problems that arise in practice when computing appropriate null distributions for hypothesis testing. Results First, we show how to compute a p-value for agreement between observed and model-predicted classifications of gene transcripts as upregulated, downregulated, or neither. Specifically, how likely are the classifications to agree to the same extent under the null distribution of the observed classification being randomized? This problem, which we call "Ternary Dot Product Distribution" owing to its mathematical form, can be viewed as a generalization of Fisher's exact test to ternary variables. We present two computationally efficient algorithms for computing the Ternary Dot Product Distribution and investigate its combinatorial structure analytically and numerically to establish computational complexity bounds. Second, we develop an algorithm for efficiently performing random sampling of causal graphs. This enables p-value computation under a different, equally important null distribution obtained by randomizing the graph topology but keeping fixed its basic structure: connectedness and the positive and negative in- and out-degrees of each vertex. We provide an algorithm for sampling a graph from this distribution uniformly at random. We also highlight theoretical

  1. Fungal agents of dermatophytosis in dogs and cats from Xanxerê county, Santa CatarinaAgentes fúngicos da dermatofitose em cães e gatos do município de Xanxerê, Santa Catarina

    Directory of Open Access Journals (Sweden)

    Andreia Ines Ferronatto

    2011-08-01

    Full Text Available Dermatophytosis is one of the main diseases of soft tissue pets, especially dogs and cats, as the etiological agents are responsible for important zoonotic disease sometimes difficult to treat. The presence of pathogenic fungi on the skin lesions associated with alopecia, border demarcated, and itching of mild intensity characterizes dermatophytosis. This study aimed to determine the prevalence of fungal species involved in cases of dermatophytosis in companion animals showing lesions. We performed skin scrapings of skin lesions of 41 (forty-one dogs and 7 (seven cats. The samples were sent to the Laboratory of Microbiology UNOESC - Xanxerê for possible isolation. The hair of animals were subjected to direct examination under a microscope to detect the existence of possible changes. Subsequently, it was the cultivation of the samples in Sabouraud agar containing antibiotics. Fungi were identified by macroscopic morphology of the microculture technique. In dogs, the direct examination reported eleven (26.8% positive by the visualization of lesions and arthroconidia. After cultivation of 41 samples collected from dogs, six (14.6% showed a growth of dermatophytes. Of the positive samples, 50% (3/6 were identified as Microsporum canis, 33.30% (2/6 and M. gypseum and 16.67% (1/6 and M. nanum. In cats, the seven samples tested by direct examination, three (42.8% were positive, however no positive cultures were obtained in cats, when the exam. Dermatophytosis was confirmed in a few animals, even upon the occurrence of lesions highly suggestive.A dermatofitose é uma das principais enfermidades tegumentares de animais de companhia, em especial cães e gatos, uma vez que seus agentes etiológicos são responsáveis por importante zoonose por vezes de difícil tratamento. A presença de fungos patogênicos na pele, associado às lesões alopécicas, de bordas delimitadas, e com prurido de discretas intensidades caracteriza a dermatofitose. Este estudo

  2. 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

  3. Influência dos agentes clareadores e um refrigerante a base de cola na microdureza do esmalte dental e a ação da saliva na superfície tratada = Influence of bleaching agents and a carbonated soft drink on dental enamel microhardness as well as the artificial saliva effect on the treated surface

    OpenAIRE

    Araújo, Rodrigo Maximo de; Torres, Carlos Rocha Gomes; de Araújo, Maria Amélia Máximo

    2006-01-01

    O objetivo deste estudo foi avaliar os efeitos de três agentes clareadores e uma bebida carbonatada, à base de cola, sobre a microdureza do esmalte dental, assim como os efeitos da saliva artificial sobre o esmalte tratado com estes agentes. Foram utilizados quarenta dentes incisivos bovinos embutidos em resina acrílica. As amostras foram avaliadas em microdurômetro (Future Tech FM 700) após a divisão em quatro grupos, uma leitura inicial da microdureza serviu como controle do experimento: Gr...

  4. Clarity and causality needed in claims about Big Gods.

    Science.gov (United States)

    Watts, Joseph; Bulbulia, Joseph; Gray, Russell D; Atkinson, Quentin D

    2016-01-01

    We welcome Norenzayan et al.'s claim that the prosocial effects of beliefs in supernatural agents extend beyond Big Gods. To date, however, supporting evidence has focused on the Abrahamic Big God, making generalisations difficult. We discuss a recent study that highlights the need for clarity about the causal path by which supernatural beliefs affect the evolution of big societies. PMID:26948745

  5. Avaliação da vanilina como agente antimicrobiano em abacaxi 'Pérola' minimamente processado Evaluation of vanillin as an antimicrobial agent on fresh-cut 'Pérola' pineapple

    Directory of Open Access Journals (Sweden)

    Lucimara Rogéria Antoniolli

    2004-09-01

    Full Text Available Procurou-se avaliar os efeitos da vanilina como agente antimicrobiano, bem como o nível de injúria física como fator de contaminação inicial em abacaxi (Ananas comosus (L. Meer cv. Pérola minimamente processado. Fatias e cubos foram obtidos a partir de frutos sanitizados, descascados e fatiados mecanicamente. Os dois tipos de corte foram imersos, separadamente, em água (controle ou soluções de vanilina 3000 ou 5000mg.L-1, durante 30 segundos. Após período de repouso, para drenagem do excesso de líquido, foram acondicionados em embalagens de polietileno tereftalato e mantidos à temperatura de 4 ± 1°C durante 12 dias. As análises microbiológicas, realizadas em intervalos de 3 dias, envolveram a contagem de microrganismos aeróbios mesófilos e de bolores e leveduras e a determinação de coliformes totais e fecais. A utilização de vanilina mostrou-se ineficiente no controle do crescimento da população de microrganismos aeróbios mesófilos e de bolores e leveduras em abacaxi 'Pérola' minimamente processado. O maior nível de injúrias físicas efetuado nos cubos parece favorecer a contaminação inicial do produto.The purpose of this research was to evaluate the effects of vanillin as an antimicrobial agent, as well as the relationship between the injury degree and initial contamination in fresh-cut pineapple (Ananas comosus (L. Meer cv. Pérola. Slices and cubes were obtained from whole fruits that were mechanically peeled and sliced after sanitization. Both kinds of cutting were dipped in pure water (control or vanillin solutions 3000 or 5000mg.L-1, for 30 seconds. After that, the liquid was drained, slices and cubes were placed in polyethylene terephtalate packages and stored at 4 ± 1°C during 12 days. Microbiological analyses were carried out every 3 days and involved mesophile aerobic counts, molds and yeasts and total and fecal coliforms determination. The use of vanillin was inefficient for the control of mesophile

  6. ["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

  7. 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.

  8. Tolerância a agente curarizante provocada pela administração repetida da droga

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Zanini

    1974-03-01

    Full Text Available Baseados em teoria discutível segundo a qual a miastenia grave é provocada pela presença no sangue de substância curarizante liberada pelo timo, tentou-se reproduzir um modelo experimental. Foram utilizados 40 ratos, criados nas mesmas condições, nascidos no mesmo dia, pesando ao redor de 350 g e divididos em 4 grupos: o Grupo I não foi manuseado; no Grupo II foi injetada solução fisiológica, 1 ml i.p. durante 6 semanas; no Grupo III foi injetada a dimetil tubocurarina (DMT 2,8 mcg/kg i.p., durante o mesmo tempo; no Grupo IV 14 mcg/kg da mesma droga foram injetados i.p. Uma semana após a última injeção i.p. os ratos, anestesiados, foram preparados para registro neuromuscular. O nervo ciático foi estimulado nas freqüências de 0,33 pulsos/seg, 70 pulsos/seg (séries de 10 pulsos a intervalos de 3 seg, 70 pulsos/seg (mantidos por 15 seg e novamente 0,33 pulsos/seg logo após a tetanização. A dose curarizante de DMT foi determinada por uma "terceira parte cega" quando 80% do bloqueio era alcançado. Quando apenas 10 estímulos em alta freqüência foram aplicados ao nervo, foi observada diferença significativa (p<0.05 na resposta: Grupo I, 46,50 ± 20,00 g+; Grupo II, 55,25 ± 11,33 g+; Grupo III, 37,25 ± 10,77 g+; Grupo IV 37,00 ± 12,74 g+. Diferenças significantes de força muscular foram também observadas após a tetanização mantida: Grupo I, 79,00 ± 16,21 g+; Grupo II, 76,75 ± 15,23 g+; Grupo III, 59,12 ± 17,38 g+; Grupo IV, 61,62 ± 14,74 g. Doses significamente mais altas de curare i.v. foram necessárias no grupo injetado diariamente com a maior dose de curare do que em qualquer dos outros grupos (p < 0,01: Grupo I, 3,62 ± 1,17 mcg/kg; Grupo II, 3,69 ± 1,21 mcg/kg; Grupo III, 4,01 ± 0,80 mcg/kg; Grupo IV, 5,48 ± 1,40 mcg/kg. Tais resultados mostram que a administração crônica do curare leva ao enfraquecimento físico e hiposensibilidade à droga. Isto sugere que embora a existência de subst

  9. Identificacion de marcadores genéticos del agente causal del marchitamiento del clavel fusarium oxysporum f.sp. dianthi mediante amplificacion arbitraria de fragmentos polimórficos de adn

    OpenAIRE

    Arbeláez G.; Hernández J.; Junca H.; Posada M.; Portillo P. Del

    2011-01-01

    La técnica de Amplificación Arbitraria de Fragmentos Polimórficos de ADN (RAPD) fue utilizada para identificar marcadores genéticos útiles para el desarrollo de un método diagnóstico para Fusarium oxysporum f.sp. dianthi, el agente etiológico de la enfermedad del marchitamiento del clavel. Con el fin de identificar fragmentos genéticos característicos de este patógeno, un total de 18 aislados diferentes, provenientes de diferentes lugares del mundo y 17 cepas de F. oxysporum de otras formas e...

  10. Efeito do extrato de alho na quebra de dormência de gemas de videiras e no controle in vitro do agente causal da antracnose (Elsinoe ampelina Shear Effect of garlic extract on bud break of grapevines and in vitro control of causal agent of antracnose (Elsinoe ampelina Shear

    Directory of Open Access Journals (Sweden)

    Renato Vasconcelos Botelho

    2009-03-01

    Full Text Available Considerando a redução ou eliminação do uso de substâncias sintéticas que preconizam os sistemas sustentáveis de produção de frutas, este trabalho teve como objetivo a busca de novas alternativas para a quebra de dormência e o controle de doenças em videiras. Estacas de videira contendo uma gema foram pulverizadas com os seguintes tratamentos: 1 testemunha; 2 OV (óleo vegetal 1%; 3 extrato de alho (EA 3%; 4 EA 3% + OV 1%. Posteriormente, as estacas foram mantidas em câmara de crescimento (25±2.5ºC por 56 dias. O único tratamento que estimulou a brotação das estacas de videira cv. Isabel Precoce foi o EA 3% + OV 1%, que atingiu 35% de brotação, diferindo estatisticamente dos tratamentos- testemunha (12,5%, OV 1% (17,5% e EA 3% (15,0%. Provavelmente, o estádio de endodormência profunda das gemas, após apenas 90 horas de frio ( Considering the reduction or elimination of synthetic compounds used in sustainable fruit production systems, this work aimed to search for new alternatives for bud break dormancy and diseases control in grapevines. Single-bud cuttings of grapevines were sprayed with the following treatments: 1 control, 2 1% SO (soybean oil, 3 3% GE (garlic extract, 4 3% GE + 1% SO. After that, the cuttings were kept in a growth chamber (25±2.5ºC for 56 days. The unique treatment that stimulated sprouting of grapevines cv. Isabel Precoce was 3% GE + 1% S, that reached 35% sprouting, differing statistically from the control (12.5%, 1% SO (17.5% and 3% GE (15.0%. Probably, the stage of deep endodormancy of buds, after only 90 chilling hours (< 7.0ºC, avoided better results of bud breaks treatments. Three experiments were carried out in vitro, with different garlic extract doses aiming to evaluate the control of the fungus Elsinoe ampelina. In all trials, there were quadratic effects on mycelial growth, without differences between garlic extract treatments, evidencing its fungicide effect, even for the lowest dose of 0.0615% GE.

  11. Classical planning and causal implicatures

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Benotti, Luciana

    to 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......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...

  12. Influência do agente de união na resistência ao cisalhamento da interface titânio/polímero de vidro Bonding agent influence on shear bond strength of titanium/polyglass interface

    Directory of Open Access Journals (Sweden)

    Denise Kanashiro Oyafuso

    2003-09-01

    Full Text Available Há poucas informações em relação à efetividade da união entre compósitos e superfícies metálicas. Este estudo avaliou a influência de dois agentes de união na resistência ao cisalhamento da interface formada pelo titânio comercialmente puro (Ti cp e um compósito (Artglass/ Heraeus Kulzer. Vinte estruturas metálicas (4mm de diâmetro e 5mm de altura de titânio grau 1 foram fundidas, jateadas com partículas de óxido de alumínio (250ìm e separadas em dois grupos. Para cada grupo foi utilizado um agente de união (Sistema Siloc-Pre ou Retention Flow como procedimento anterior à aplicação do material opaco. Sobre este foram aplicados camadas do polímero referente à dentina com o auxílio de uma matriz de teflon. A manipulação e polimerização foram realizadas de acordo com as recomendações do fabricante. Os corpos-de-prova foram armazenados em água destilada por 24 horas à 37ºC e termociclados (5º e 55ºC/ 500ciclos. O teste de resistência ao cisalhamento foi realizado em uma máquina de ensaios universal (Instron com velocidade de 5mm/min. Os dados foram tratados estatisticamente pela Análise de Variância one-way (á=0,5. Os resultados indicaram que o sistema adesivo Retention Flow foi estatisticamente melhor do que o Siloc, com médias de 20,74MPa e 11,65MPa, respectivamente. Foi possível concluir que o sistema de união influenciou na adesão entre o titânio grau I e o polímero de vidro estudado.There is little information regarding bond strengths of polyglass to metal alloys. This study evaluated the influence of bonding system on shear bond strength of a composite resin (Artglass/Heraeus Kulzer to cast titanium (Ti. Twenty metallic structures (4mm in diameter, 5mm thick of titanium grade I were cast shaped and abraded with 250mm aluminum oxide and separated into two groups. For each group was applied one bonding system (Siloc or Retention Flow before opaque and dentin polymer superposition. This procedure

  13. 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.

  14. Causal Structure and Spacetime Singularities

    CERN Document Server

    Stoica, Ovidiu Cristinel

    2015-01-01

    In General Relativity the metric can be recovered from the structure of the lightcones and a measure giving the volume element. Since the causal structure seems to be simpler than the Lorentzian manifold structure, this suggests that it is more fundamental. But there are cases when seemingly healthy causal structure and measure determine a singular metric. Here it is shown that this is not a bug, but a feature, because big-bang and black hole singularities are instances of this situation. But while the metric is special at singularities, being singular, the causal structure and the measure are not special in an explicit way at singularities. Therefore, considering the causal structure more fundamental than the metric provides a more natural framework to deal with spacetime singularities.

  15. 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...

  16. 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...

  17. 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...

  18. Formação de Agentes Comunitárias de Saúde para o enfrentamento da violência de gênero: contribuições da Educação Popular e da pedagogia feminista

    Directory of Open Access Journals (Sweden)

    Sônia Maria Dantas Berger

    2014-12-01

    Full Text Available Apresentam-se resultados parciais de uma pesquisa-ação que investigou a violência de gênero na Estratégia Saúde da Família, com especial atenção sobre as Agentes Comunitárias de Saúde (ACSs, atores estratégicos na atenção a mulheres em situação de violência. Dentre as atividades de pesquisa e intervenção desenvolvidas, incluem-se oficinas com as ACSs para a discussão dialogada dos resultados da pesquisa. Tomando-se como referência os pressupostos da Educação Popular e da pedagogia feminista, conclui-se que as oficinas representaram um valioso recurso político-pedagógico, permitindo uma fecunda interação dialógica entre academia e serviços de saúde e oferecendo visibilidade e reconhecimento às vozes e às ricas experiências de vida e trabalho das ACSs contribuindo, assim, para uma construção compartilhada do conhecimento que fortalece práxis comprometidas com transformações na assistência à saúde e nas relações sociais mais amplas.

  19. 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...

  20. The role of hyperbaric oxygen therapy (HOT as an otoprotection agent against cisplatin ototoxicity Efeito otoprotetor da oxigenoterapia hiperbárica na toxicidade causada pela cisplatina

    Directory of Open Access Journals (Sweden)

    Camila C. Yassuda

    2008-01-01

    Medicina de Ribeirao Preto da Universidade de São Paulo nos anos de 2005 e 2006. Objetivo: Avaliar o papel da Oxigenoterapia Hiperbárica como agente otoprotector contra a toxicidade de drogas. MÉTODOS: Cobaias albinas divididas em 2 grupos Grupo A: com 5 cobaias (10 cócleas que receberam cisplatina 8,0 mg/kg/dia, via intraperitoneal por 3 dias, submetidas posteriormente a OHB. Grupo B: com 3 cobaias (6 cócleas que receberam cisplatina 8,0 mg/kg/dia, via intraperitoneal por 3 dias. As cobaias foram avaliadas através de otoemissões acústicas (OEA e por microscopia eletrônica de varredura (MEV. Resultados: Encontramos no grupo B perda da função auditiva medida pela OEA e distorção das células ciliares externas a MEV. No grupo A, a MEV as células ciliares externas foram preservadas em sua grande maioria. CONCLUSÃO: Assim podemos supor que a Oxigenoterapia Hiperbárica tem um efeito otoprotetor contra a ototoxicidade induzida pela cisplatina.

  1. Identification on Causal Agent of Dragonfruit Stem Rot and Indoor Determination of Fungicide Toxicity%火龙果茎腐病病原鉴定及室内药剂毒力测定

    Institute of Scientific and Technical Information of China (English)

    梁秋玲; 韦健; 李孝云; 王力前

    2011-01-01

    The stem rot disease of dragon fruit was diagnosed and the casual pathogen was isolated and identified. Dragonfruit varietal differences in resistance to the disease were investigated. The results showed that the casual agent was Bipolaris cactivora. White dragonfruit with yellow peel showed the highest resistance to the fungus, followed, in sequence, by white dragonfruit with red peel, and red dragonfruit with red peel. Eight fungicides were screened, and the result showed that propiconazole (25%EC) had the best control effect.%对火龙果茎腐病进行诊断和鉴定,观察其病原菌形态及培养性状,并初步测定不同火龙果品种的抗病性及几种药剂对该病害的室内毒力.鉴定结果表明,火龙果茎腐病病原为Bipolaris cactivora,30℃为该菌菌丝生长最适温度.初步发现黄皮白肉火龙果对该菌的抗病性最强,红皮白肉火龙果次之,红皮红肉火龙果抗病性最差.供试药剂中25%丙环唑的效果最好.

  2. 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,...

  3. Influência da temperatura do ar de secagem e da concentração de agente carreador sobre as propriedades físico-químicas do suco de açaí em pó Influence of drying air temperature and carrier agent concentration on the physicochemical properties of açai juice powder

    Directory of Open Access Journals (Sweden)

    Renata Valeriano Tonon

    2009-06-01

    Full Text Available A influência da temperatura do ar de secagem e da concentração de agente carreador sobre as propriedades físico-químicas do suco de açaí em pó produzido por spray drying foi avaliada. O processo foi realizado em um mini spray dryer de bancada e maltodextrina 10DE foi utilizada como agente carreador. A temperatura do ar de secagem variou de 138 a 202 °C e a concentração de maltodextrina variou de 10 a 30%. As características analisadas foram: umidade, higroscopicidade, retenção de antocianinas, cor, distribuição do tamanho de partículas e morfologia. O aumento da temperatura resultou em partículas maiores, menos úmidas, mais higroscópicas e com menor retenção de antocianinas, além de provocar uma diminuição do parâmetro de cor L* e do ângulo de tom H*. O aumento na concentração de maltodextrina resultou em partículas maiores e menos higroscópicas, com maior luminosidade (L*, menores valores de C* e maiores valores de H*. Em relação à morfologia, o aumento da temperatura levou à formação de uma maior quantidade de partículas com superfície lisa, fato atribuído à maior transferência de calor e, consequentemente, à formação mais rápida de uma membrana ao redor da gota atomizada.The objective of this work was to study the influence of inlet air temperature and maltodextrin concentration on the physicochemical properties of açai juice powder produced by spray drying. The process was carried out in a mini spray dryer and the maltodextrin 10DE was used as carrier agent. Inlet air temperature varied from 138 to 202 °C and maltodextrin concentration varied from 10 to 30%. The characteristics analyzed were: moisture content, hygroscopicity, anthocyanin retention, color, particle size distribution, and morphology. The increase in the temperature resulted in particles with larger size, less moisture content, more hygroscopy and with lower anthocyanin retention, besides promoting a reduction in the color

  4. 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

  5. Uniform infinite and Gibbs causal triangulations

    NARCIS (Netherlands)

    Zohren, Stefan

    2012-01-01

    We discuss uniform infinite causal triangulations (UICT) and Gibbs causal triangulations which are probabilistic models for the causal dynamical triangulations (CDT) approach to quantum gravity. Since there is a bijection between causal triangulations and planar rooted trees we first discuss some as

  6. Causality and Tense - two temporal structure builders

    NARCIS (Netherlands)

    Oversteegen, E.

    2005-01-01

    By force of causes precede effects, causality contributes to the temporal meaning of discourse. In case of semantic causal relations, this contribution is straightforward, but in case of epistemic causal relations, it is not. In order to gain insight into the semantics of epistemic causal relations,

  7. Identificacion de marcadores genéticos del agente causal del marchitamiento del clavel fusarium oxysporum f.sp. dianthi mediante amplificacion arbitraria de fragmentos polimórficos de adn

    Directory of Open Access Journals (Sweden)

    Arbeláez G.

    1998-12-01

    Full Text Available La técnica de Amplificación Arbitraria de Fragmentos Polimórficos de ADN (RAPD fue utilizada para identificar marcadores genéticos útiles para el desarrollo de un método diagnóstico para Fusarium oxysporum f.sp. dianthi, el agente etiológico de la enfermedad del marchitamiento del clavel. Con el fin de identificar fragmentos genéticos característicos de este patógeno, un total de 18 aislados diferentes, provenientes de diferentes lugares del mundo y 17 cepas de F. oxysporum de otras formas especiales fueron amplificadas utilizando 15 iniciadores diferentes. Aunque ninguno de los iniciadores empleados en este estudio amplificó una banda común a todas las formas especiales dianthi, el iniciador OPA 17 mostró un patrón de RAPD que permitió la identificación de cuatro grupos polimórficos dentro de este grupo taxonómico. Este mismo iniciador, permitió la discriminación entre aislados de Fusarium oxysporum f.sp. dianthi y cepas de F. oxysporum de otras formas especiales. No se observó una correlación directa entre el patrón de RAPD y las razas reportadas para F. oxysporum f.sp. dianthi, previamente determinadas mediante ensayos biológicos por otros grupos de investigadores. Los análisis de hibridación molecular con fragmentos escogidos de estos patrones de RAPD, permitieron el reconocimiento selectivo de los cuatro grupos descritos. Los fragmentos genómicos identificados, son candidatos para el desarrollo de un  sistema diagnóstico por PCR para este patógeno del clavel.

  8. Vulnerabilidade e sofrimento no trabalho do agente comunitário de saúde no Programa de Saúde da Família Vulnerabilidad y sufrimiento en el trabajo del agente comunitario de salud en el Programa Salud de la Familia Vulnerability and suffering in the work of a community health agent in the Family Health Program

    Directory of Open Access Journals (Sweden)

    Wânia Regina Veiga Martines

    2007-09-01

    Full Text Available A pesquisa, de natureza qualitativa, teve como núcleo de interesse investigativo as representações e as significações que um grupo de Agentes Comunitários de Saúde (ACSs possui acerca das vulnerabilidades para o sofrimento no trabalho a que estão expostos, assim como as próprias manifestações deste sofrimento ao desempenharem suas ações relativas ao Programa de Saúde da Família (PSF.A entrevista semi-estruturada com um grupo de ACSs, explorou o significado de ser ACS e a percepção da organização do trabalho; a análise foi embasada no referencial teórico-metodológico da hermenêutica e nas teorias relacionadas à psicodinâmica do trabalho. Os achados mostram a existência de uma importante vulnerabilidade ao sofrimento, gerada principalmente pela ideação idealizada da própria prática e pela escassa perspectiva de rearranjo dos ingredientes constitutivos da organização do trabalho, já que este profissional depende de fatores alheios ao seu espectro de alcance, que inclui as limitações do modelo assistencial proposto pelo PSF.La investigación, de naturaleza cualitativa, tuvo como centro de interés un grupo de Agentes Comunitarios de Salud (ACSs sobre las vulnerabilidades para el sufrimiento en el trabajo a que están expuestos, al desempeñar sus acciones profesionales en el Programa Salud de la Familia (PSF.La entrevista semi estructurada exploró el significado de ser ACS y la percepción de la organización del trabajo; el análisis fue efectuado con base al referencial teórico-metodológico de la hermenéutica y de las teorías relacionadas a la psicodinámica del trabajo.Los descubrimientos muestran la existencia de una importante vulnerabilidad al sufrimiento, generada principalmente por la creación de las ideas idealizadas de la propia práctica y por la escasa perspectiva de la disposición de los ingredientes constitutivos de la organización del trabajo, siendo que el profesional depende de factores

  9. Agente Comunitário de Saúde no controle da tuberculose na Atenção Primária à Saúde Agente Comunitario de Salud en el control de la tuberculosis en la Atención Primaria a la Salud The Community Health Agent in the control of tuberculosis in Primary Health Care

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    Juliane de Almeida Crispim

    2012-01-01

    Full Text Available OBJETIVO: Avaliar o desempenho do Agente Comunitário de Saúde (ACS no controle da tuberculose (TB em áreas assistidas pela Estratégia Saúde da Família (ESF, sendo estabelecida uma análise comparativa com os ACSs inscritos nas Unidades Básicas de Saúde (UBS tradicionais. MÉTODOS: Estudo transversal, realizado em um município prioritário para o controle da TB no Estado de São Paulo, com uma amostra mínima de 108 ACSs das ESFs e das UBSs. Para a coleta de dados, utilizou-se um instrumento elaborado para a Atenção Primária à Saúde (APS, adaptado para atenção à TB. RESULTADOS: No que concerne às ações de controle da TB, observou-se que não houve diferenças com significância estatística entre o desempenho dos ACSs das unidades da ESF e os inscritos nas UBSs. CONCLUSÃO: O estudo evidenciou a fragilidade dos ACSs em incorporar na sua prática as ações de controle da TB nas distintas modalidades de APS, apesar do destaque dado à ESF.OBJETIVO: Evaluar el desempeño del Agente Comunitario de Salud (ACS en el control de la tuberculosis (TB en áreas asistidas por la Estrategia Salud de la Familia (ESF, siendo establecido un análisis comparativo con los ACSs inscritos en las Unidades Básicas de Salud (UBS tradicionales. MÉTODOS: Estudio transversal, realizado en un municipio prioritario para el control de la TB en el Estado de Sao Paulo, con una muestra mínima de 108 ACSs de las ESFs y de las UBSs. Para la recolección de los datos se utilizó un instrumento elaborado para la Atención Primaria a la Salud (APS, adaptado para la atención a la TB. RESULTADOS: En lo que concierne a las acciones de control de la TB, se observó que no hubo diferencias con significancia estadística entre el desempeño de los ACSs de las unidades de la ESF y los inscritos en las UBSs. CONCLUSIÓN: En el estudio se evidenció la fragilidad de los ACSs para incorporar en su práctica acciones de control de la TB en las distintas modalidades de

  10. Diagnóstico ambiental do município de Sinimbu (RS: a ação dos agentes transformadores na construção da paisagem

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    Anderson Luís Ruhoff

    2002-01-01

    Full Text Available O trabalho teve por objetivo interpretar a formaçãodo atual espaço geográfico no município de Sinimbu(RS, tendo por base o estudo da interrelação entreas ações antrópicas e o suporte físico-biótico na formação da atual paisagem. Buscou-se o entendimento da paisagem através da relação homem x naturezae dos elementos contidos nessa relação para determinar a estrutura e a dinâmica do sistema ambientalque funciona e evolui em conjunto. Identificaramse os principais agentes transformadores da paisagem e, com a interpretação de imagens de satélite,caracterizaram-se as diversidades da paisagem. Porfim, evidenciou-se a correlação entre os elementosdo quadro natural com as ações antrópicas.

  11. Avaliação da sensibilidade da cultura de leite do tanque para isolamento de agentes contagiosos da mastite bovina Evaluation of the sensitivity of bulk tank milk cultures for the isolation of contagious bovine mastitis pathogens

    Directory of Open Access Journals (Sweden)

    Maria Aparecida V. P. Brito

    1998-01-01

    Full Text Available Amostras de leite total (leite do tanque de 33 rebanhos foram coletadas na plataforma de recepção da indústria laticinista e cultivadas para detectar patógenos específicos (contagiosos da mastite. Foi feita a contagem de células somáticas (CCS das amostras utilizando o equipamento Fossomatic 90. Em 13 e 12 rebanhos avaliaram-se duas e três amostras semanais consecutivas, respectivamente, e em oito avaliou-se apenas uma. Foram também examinadas três amostras diárias consecutivas do leite do tanque e amostras dos quartos mamários individuais, coletadas na própria fazenda, de todas as vacas em lactação de quatro rebanhos (A, B, C e D. As amostras de leite dos quartos mamários individuais foram cultivadas em ágar sangue e as amostras do tanque, em placas de TKT, Sal Manitol, MacConkey e Sabouraud contendo cloranfenicol. Dos 33 rebanhos cujas amostras foram obtidas na plataforma de recepção da indústria, isolou-se Staphylococcus aureus de 26, nove desses em associação com Streptococcus agalactiae e em três rebanhos isolou-se somente S. agalactiae. Nove rebanhos tiveram CCS acima de 500.000 ml-1 e 21, abaixo de 400.000 ml-1. Em cinco dos nove rebanhos com CCS acima de 500.000 ml-1 foram isolados S. aureus e S. agalactiae, em três, apenas S. aureus e em um, apenas S. agalactiae. Seis rebanhos apresentaram CCS abaixo de 200.000 ml-1; de um deles foram isolados S. aureus e S. agalactiae, de três, S. aureus e os outros dois foram negativos para estes dois patógenos. Os resultados encontrados nos quatro rebanhos cujas amostras foram coletadas na própria fazenda mostraram que S. aureus foi isolado nas seguintes porcentagens dos animais: 1,8%, 19,2%, 17,0% e 8,4% e dos quartos mamários: 0,9%, 5,9%, 5,4% e 2,2%, respectivamente, para os rebanhos A, B, C e D. S. agalactiae foi isolado dos rebanhos A, C e D. Nestes três rebanhos, as porcentagens de isolamento foram, respectivamente, 1,8%, 10,6% e 8,4% para as vacas e 0,46%, 3,8% e 3

  12. Statistics, Causality and Bell's theorem

    CERN Document Server

    Gill, Richard D

    2012-01-01

    Bell's (1964) theorem is popularly supposed to establish the non-locality of quantum physics as a mathematical-physical theory. Building from this, observed violation of Bell's inequality in experiments such as that of Aspect and coworkers (1982) is popularly supposed to provide empirical proof of non-locality in the real world. This paper reviews recent work on Bell's theorem, linking it to issues in causality as understood by statisticians. The paper starts with a new proof of a strong (finite sample) version of Bell's theorem which relies only on elementary arithmetic and (counting) probability. This proof underscores the fact that Bell's theorem tells us that quantum theory is incompatible with the conjunction of three cherished and formerly uncontroversial physical principles, nicknamed here locality, realism, and freedom. The first, locality, is obviously connected to causality: causal influences need time to propagate spatially. Less obviously, the other two principles, realism and freedom, are also fo...

  13. Introductive remarks on causal inference

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    Silvana A. Romio

    2013-05-01

    Full Text Available One of the more challenging issues in epidemiological research is being able to provide an unbiased estimate of the causal exposure-disease effect, to assess the possible etiological mechanisms and the implication for public health. A major source of bias is confounding, which can spuriously create or mask the causal relationship. In the last ten years, methodological research has been developed to better de_ne the concept of causation in epidemiology and some important achievements have resulted in new statistical models. In this review, we aim to show how a technique the well known by statisticians, i.e. standardization, can be seen as a method to estimate causal e_ects, equivalent under certain conditions to the inverse probability treatment weight procedure.

  14. 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

  15. Causal reasoning with mental models

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    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.

  16. Gravitation, Causality, and Quantum Consistency

    CERN Document Server

    Hertzberg, Mark P

    2016-01-01

    We examine the role of consistency with causality and quantum mechanics in determining the properties of gravitation. We begin by constructing two different classes of interacting theories of massless spin 2 particles -- gravitons. One involves coupling the graviton with the lowest number of derivatives to matter, the other involves coupling the graviton with higher derivatives to matter, making use of the linearized Riemann tensor. The first class requires an infinite tower of terms for consistency, which is known to lead uniquely to general relativity. The second class only requires a finite number of terms for consistency, which appears as a new class of theories of massless spin 2. We recap the causal consistency of general relativity and show how this fails in the second class for the special case of coupling to photons, exploiting related calculations in the literature. In an upcoming publication [1] this result is generalized to a much broader set of theories. Then, as a causal modification of general ...

  17. Causality and Primordial Tensor Modes

    CERN Document Server

    Baumann, Daniel

    2009-01-01

    We introduce the real space correlation function of $B$-mode polarization of the cosmic microwave background (CMB) as a probe of superhorizon tensor perturbations created by inflation. By causality, any non-inflationary mechanism for gravitational wave production after reheating, like global phase transitions or cosmic strings, must have vanishing correlations for angular separations greater than the angle subtended by the particle horizon at recombination, i.e. $\\theta \\gtrsim 2^\\circ$. Since ordinary $B$-modes are defined non-locally in terms of the Stokes parameters $Q$ and $U$ and therefore don't have to respect causality, special care is taken to define `causal $\\tilde B$-modes' for the analysis. We compute the real space $\\tilde B$-mode correlation function for inflation and discuss its detectability on superhorizon scales where it provides an unambiguous test of inflationary gravitational waves. The correct identification of inflationary tensor modes is crucial since it relates directly to the energy s...

  18. Causal Models for Risk Management

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    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.

  19. 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 ...

  20. Causality problem in Economic Science

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    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.

  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. 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

  3. 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...

  4. Free Fermions on causal sets

    CERN Document Server

    Noldus, Johan

    2013-01-01

    We construct a Dirac theory on causal sets; a key element in the construction being that the causet must be regarded as emergent in an appropriate sense too. We further notice that mixed norm spaces appear in the construction allowing for negative norm particles and "ghosts".

  5. Entanglement, holography and causal diamonds

    Science.gov (United States)

    de Boer, Jan; Haehl, Felix M.; Heller, Michal P.; Myers, Robert C.

    2016-08-01

    We argue that the degrees of freedom in a d-dimensional CFT can be reorganized 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 2 d-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 entanglemententropy from this unifying point of view. We demonstrate that for small perturbations of the vacuum, our observables obey linear two-derivative equations of motion on the space of causal diamonds. In two dimensions, the latter is given by a product of two copies of a two-dimensional de Sitter space. For a class of universal states, we show that the entanglement entropy and its spin-three generalization obey nonlinear equations of motion with local interactions on this moduli space, which can be identified with Liouville and Toda equations, respectively. This suggests the possibility of extending the definition of our new observables beyond the linear level more generally and in such a way that they give rise to new dynamically interacting theories on the moduli space of causal diamonds. Various challenges one has to face in order to implement this idea are discussed.

  6. Representações do envelhecimento em agentes comunitários da saúde e profissionais da enfermagem comunitária: aspectos psicológicos do processo saúde-doença Representations of aging for community health agents and nursing professionals: psychological aspects of the health-disease process

    Directory of Open Access Journals (Sweden)

    Rochele Paz Fonseca

    2008-08-01

    Full Text Available No âmbito do tema saúde pública e envelhecimento, o objetivo desse estudo foi averiguar quais são as representações do processo de envelhecimento para profissionais da saúde pública e como essas se expressam na atenção à saúde, no bem-estar e no cuidado do idoso. Participaram 27 profissionais (dez agentes comunitários de saúde e dezessete profissionais de enfermagem. Utilizaram-se dois instrumentos, um questionário sociocultural e um questionário sobre as representações do envelhecimento. Os dados foram analisados qualitativa e quantitativamente (teste qui-quadrado. As palavras mais representativas para expressar o envelhecimento foram aposentadoria e descanso. O fator que mais influenciou o bem-estar e o cuidado do indivíduo idoso foi uma boa rede familiar. Quanto à definição de cuidado, os aspectos biológicos foram os mais freqüentes. A amostra apresentou noções sobre a doença de Alzheimer. Assim sendo, os dados encontrados trazem implicações para a capacitação de recursos humanos. Os agentes de saúde e os profissionais de enfermagem devem ser auxiliados no processo de construção de uma melhor compreensão do contexto biopsicossocial em que o envelhecimento está inserido.This paper addresses the aging process in the context of public health, with emphasis to human resources and to how aging is perceived by the public health professionals. The aim of this study was to identify the representations of the aging process for public health professionals and how these representations are expressed in health care, well-being and elderly care. The sample included 27 public health professionals, 10 community health agents and 17 nursing professionals. Two instruments were used, a sociocultural questionnaire and a questionnaire about aging representations. Data analysis included qualitative and quantitative procedures (Chi-square test. Among the main findings, the most representative words used in relation to aging were

  7. Avaliação do método de disco-difusão para determinação da eficácia da terbinafina in vitro em agentes de micoses superficiais e subcutâneas Evaluation of the disk-diffusion method to determine the in vitro efficacy of terbinafine against subcutaneous and superficial mycoses agents

    Directory of Open Access Journals (Sweden)

    Hilda Conceição Diogo

    2010-06-01

    Full Text Available FUNDAMENTOS: As micoses superficiais e subcutâneas têm alta prevalência e, muitas vezes, caráter crônico, necessitando tratamentos tópicos e/ou sistêmicos com antifúngicos. As drogas de escolha são azóis e alilaminas (terbinafina. É necessário avaliar a eficácia das drogas para tratamento em humanos e em animais. Estudos para avaliar in vitro a ação dos antimicóticos são raros, especialmente, contra fungos filamentosos. OBJETIVO: Avaliar a eficácia in vitro da terbinafina pelo método de disco-difusão contra fungos filamentosos e leveduras agentes de micoses. MÉTODOS: Avaliou-se a ação da terbinafina (0,125µg-100µg contra dez espécies fúngicas pelos métodos discodifusão e microdiluição/referência, para determinar a concentração inibitória mínima (MIC. RESULTADOS: Observou-se alta sensibilidade à terbinafina em: T. rubrum, M. gypseum, T. mentagrophytes, T. tonsurans, M. canis, C. carrionii e E. floccosum (halo ≥ 40mm com disco de 0,125µg. S. hyalinum e C. parapsilosis foram considerados sensíveis, mas com halos menores. Fusarium spp. apresentou menor sensibilidade (halo=12mm com disco de 2µg; MIC 8µg/mL. CONCLUSÕES: Os resultados reiteram estudos anteriores quanto à alta eficácia da terbinafina em relação a dermatófitos. A técnica de disco-difusão foi de fácil aplicação e adequada na rotina de laboratórios clínicos.BACKGROUND: Superficial and subcutaneous mycoses have a high prevalence and, often, chronic evolution. Therefore, they need extensive treatment with topic and/or systemic antifungal agents. Azoles and alilamines (terbinafine are first-choice drugs to treat human and animal infections. Thus, evaluation of the efficacy of these drugs is important for a successful treatment. However, there are few studies that evaluate the in vitro activity of antifungal agents. OBJECTIVE: To evaluate the in vitro efficacy of terbinafine activity against filamentous fungi and yeasts that cause mycoses

  8. Partial chemical characterization of antigenic preparations of chromoblastomycosis agents Caracterização química parcial de preparações antigênicas de agentes da cromoblastomicose

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    Tania Fraga BARROS

    1999-11-01

    Full Text Available Antigenic preparations (saline, methylic, metabolic and exoantigens of four agents of chromoblastomycosis, Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora (Cladosporium carrionii and Rhinocladiella aquaspersa were obtained. Partial chemical characterization of these antigenic preparations was obtained by determination of the levels of total lipids, protein, and carbohydrates, and identification of the main sterols and carbohydrates. Methylic antigens presented the highest lipid contents, whereas metabolic antigens showed the highest carbohydrate content. Total lipid, protein, and carbohydrate levels were in the range of 2.33 to 2.00mg/ml, 0.04 to 0.02 mg/ml and 0.10 to 0.02 mg/ml, respectively, in the methylic antigens and in the range of 0.53 to 0.18mg/ml, 0.44 to 0.26mg/ml, and 1.82 to 1.02 mg/ml, respectively, in saline antigens. Total lipid, protein, and carbohydrate contents were in the range of 0.55 to 0.20mg/ml, 0.69 to 0.57mg/ml and 10.73 to 5.93mg/ml, respectively, in the metabolic antigens, and in the range of 0.55 to 0.15mg/ml, 0.62 to 0.20mg/ml and 3.55 to 0.42mg/ml, respectively, in the exoantigens. Phospholipids were not detected in the preparations. Saline and metabolic antigens and exoantigens presented hexose and the methylic antigen revealed additional pentose units in their composition. The UV light absorption spectra of the sterols revealed squalene and an ergosterol fraction in the antigens. The characterization of these antigenic preparations may be useful for serological evaluation of patients of chromoblastomycosis.Preparações antigênicas (antígenos salinos, metílicos, metabólicos e exoantígenos de quatro agentes da cromoblastomicose, Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora (Cladosporium carrionii e Rhinocladiella aquaspersa foram obtidos e foi determinada a caracterização química parcial dos mesmos. Os antígenos metílicos apresentaram os maiores teores de lípides enquanto os

  9. Influência do tipo de agente de partição da borracha nitrílica na obtenção de blendas PVC/NBR Influence of the partitioning agent on the preparation of PVC/NBR Blends

    Directory of Open Access Journals (Sweden)

    Fábio R. Passador

    2008-09-01

    Full Text Available Borrachas nitrílicas para utilização em misturas com PVC são fornecidas em forma de pó, que são recobertas com um agente de partição para evitar compactação do produto no transporte e armazenamento, além de garantir alta fluidez e livre escoamento. Neste trabalho, buscou-se estudar a influência do tipo de agente de partição da borracha nitrílica (resina de PVC e CaCO3 na obtenção de blendas PVC/NBR. As propriedades mecânicas das blendas foram avaliadas por ensaios de tração, rasgo e dureza. As blendas com NBR com agente de partição de PVC apresentaram maior tensão na ruptura e módulo elástico que as blendas em que utilizaram NBR com agente de partição de CaCO3. A morfologia foi avaliada por microscopia eletrônica de varredura sendo bastante afetada pelo tipo de agente de partição.Nitrile rubbers used in mixture with PVC resin are supplied in powder. This kind of nitrile rubber has a partitioning agent to avoid agglomeration in the particles during the transport and storage. In this study, the influence of the partitioning agent on the preparation of PVC/NBR blends was investigated. The mechanical properties of the blends were evaluated by tensile properties, tear strength and hardness. The PVC/NBR blends with partitioning agent of PVC showed an increase in the tensile stress and Young's modulus compared to the PVC/NBR blends with partitioning agent of CaCO3. The morphology of the blends examined by scanning electron microscopy demonstrated the influence of the partitioning agent.

  10. Controle biológico da murcha bacteriana do tomateiro, por Pseudomonas spp. fluorescentes Biological control of bacterial wilt of tomato by fluorescent Pseudomonas spp

    OpenAIRE

    Ana Rosa Peixoto

    1997-01-01

    Esta revisão bibliográfica teve como objetivo avaliar o potencial de antagonismo de espécies de Pseudomonas fluorescentes a Pseudomonas solanacearum, agente causal da murcha bacteriana do tomateiro. Devido a dificuldade encontrada nas estratégias utilizadas para o controle da Murcha Bacteriana por meio de métodos convencionais, alguns outros tem sido estudados, como o uso de microrganismos benéficos. As rizobactérias vem proporcionando solução viável a algumas doenças consideradas de difícil ...

  11. Psicoterapia de grupo e considerações sobre o paciente como agente da própria mudança Psicoterapia de grupo y consideraciones sobre el paciente como agente del propio cambio Group psychotherapy and considerations concerning the patient as an agent for his own change

    Directory of Open Access Journals (Sweden)

    Luiz Paulo de C. Bechelli

    2002-06-01

    Full Text Available Nas últimas décadas a psicoterapia de grupo tem merecido considerável atenção por parte dos pesquisadores. Tendo por base publicações recentes, os autores tecem considerações sobre a indicação, a necessidade de se adotar critérios de seleção, os resultados esperados e o prognóstico, bem como o processo de mudança. A revisão da literatura evidencia tendência de se reconhecer o cliente como agente de sua própria mudança, e é colocada em relevo a forma particular que este processo assume na psicoterapia de grupo.En las últimas décadas, la psicoterapia de grupo ha merecido considerable atención por parte de los investigadores. Teniendo como base publicaciones recientes, los autores hacen consideraciones sobre la indicación, la necesidad de adoptar criterios de selección, los resultados esperados y el pronóstico, así como también el proceso de cambio. La revisión de la literatura evidencia la tendencia de reconocer el cliente como agente de su proprio cambio, siendo enfatizada la forma particular que este proceso asume en la psicoterapia de grupo.In the last few decades, group psychotherapy has deserved considerable attention from researchers. Based on recent publications, the authors of this work make considerations concerning the indication, the need to adopt a selection criteria, expected results and prognoses as well as the change process. Literature review shows a tendency to recognize the client as an agent for his own change. The particular shape which is taken by this process in group psychotherapy is pointed out.

  12. 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...

  13. 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 ...

  14. 进境美国苹果星裂壳孢果腐病菌的首次截获——病原真菌的鉴定及风险分析%First interception of fruit rot( Phacidiopycnis washingtonensis) on apples imported from US——identification and risk analysis of the causal fungal agent

    Institute of Scientific and Technical Information of China (English)

    王卫芳; 胡佳; 赵立荣; 冯黎霞; 吴海荣; 胡学难; 钟国强

    2011-01-01

    广东口岸从美国华盛顿输华苹果(Malus domestica)中截获可疑腐烂病果,症状表现为果梗凹腐或萼凹腐,病部果皮暗褐色至黑色.病健交界处纹带褐色,分生孢子器黑色、颗粒状,直径0.3~0.8 mm,部分埋生或近表生,显微镜检可见无色单胞的分生孢子.分离物生长温度-3~25℃,最适为20℃,经柯赫氏法则验证确认为截获病果的病原菌.Blast分析表明从分离物基因组中扩增到的ITS基因与GenBank中已知的Phacidiopycnis washingtonensis菌株ITS序列同源性达100%.经形态特征、培养性状及ITS系统发育分析,将病原菌鉴定为苹果星裂壳孢果腐病菌(Ph.washingtonensis Xiao&J.D.Rogers,2005),在分类上隶属于半知菌亚门球壳孢目星裂壳孢属(Phacidiopycnis),此截获鉴定属我国首次.迄今为止我国尚未有该病菌发生为害的报道,本文就此病菌对我国苹果和梨产业的潜在风险进行了评估分析.%Suspicious decayed fruits of apple (Malus domestica) imported from Washington State, U. S. A.were intercepted at Guangdong port in China, which displayed symptom of stem-end rot or calyx-end rot, with dark brown to black skin and brown boundary between the diseased and health part. Black granule pycnidia of 0.3 - 0.8 mm in diameter partially immersed or nearly free on the surface of decayed fruits. Colorless, single cell conidia oozed from pycnidia were observed by microscope examination. The isolate grew at -3 -25℃,reach the optimum growth at 20℃ and were verified as the causal fungal agent by Koch's postulates. Blast analysis revealed ITS amplified from the genome DNA of isolate displayed 100% sequence similarity to known ITS of Phacidiopycnis washingtonensis strains in GenBank. On the basis of morphological characteristics, culture patterns, phylogenetic studies on ITS sequence, the causal agent of US rotten apple was identified as Ph.washingtonensis Xiao& J. D. Rogers ( 2005 ), which belongs to Deuteromycotina

  15. Designing Effective Supports for Causal Reasoning

    Science.gov (United States)

    Jonassen, David H.; Ionas, Ioan Gelu

    2008-01-01

    Causal reasoning represents one of the most basic and important cognitive processes that underpin all higher-order activities, such as conceptual understanding and problem solving. Hume called causality the "cement of the universe" [Hume (1739/2000). Causal reasoning is required for making predictions, drawing implications and inferences, and…

  16. 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.…

  17. Exploring Individual Differences in Preschoolers' Causal Stance

    Science.gov (United States)

    Alvarez, Aubry; Booth, Amy E.

    2016-01-01

    Preschoolers, as a group, are highly attuned to causality, and this attunement is known to facilitate memory, learning, and problem solving. However, recent work reveals substantial individual variability in the strength of children's "causal stance," as demonstrated by their curiosity about and preference for new causal information. In…

  18. 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…

  19. Painless causality in defect calculations

    CERN Document Server

    Cheung, C; Cheung, Charlotte; Magueijo, Joao

    1997-01-01

    Topological defects must respect causality, a statement leading to restrictive constraints on the power spectrum of the total cosmological perturbations they induce. Causality constraints have for long been known to require the presence of an under-density in the surrounding matter compensating the defect network on large scales. This so-called compensation can never be neglected and significantly complicates calculations in defect scenarios, eg. computing cosmic microwave background fluctuations. A quick and dirty way to implement the compensation are the so-called compensation fudge factors. Here we derive the complete photon-baryon-CDM backreaction effects in defect scenarios. The fudge factor comes out as an algebraic identity and so we drop the negative qualifier ``fudge''. The compensation scale is computed and physically interpreted. Secondary backreaction effects exist, and neglecting them constitutes the well-defined approximation scheme within which one should consider compensation factor calculatio...

  20. Velocity requirements for causality violation

    CERN Document Server

    Modanese, Giovanni

    2013-01-01

    It is known that the hypothetical existence of superluminal signals would imply the logical possibility of active causal violation: an observer in relative motion with respect to a primary source could in principle emit secondary superluminal signals (triggered by the primary ones) which go back in time and deactivate the primary source before the initial emission. This is a direct consequence of the structure of the Lorentz transformations, sometimes called "Regge-Tolman paradox". It is straightforward to find a formula for the velocity of the moving observer required to produce the causality violation. When applied to some recent claims of slight superluminal propagation, this formula yields a required velocity very close to the speed of light; this raises some doubts about the real physical observability of such violations. We re-compute this velocity requirement introducing a realistic delay between the reception of the primary signal and the emission of the secondary. It turns out that for -any- delay it...

  1. Phenomenology of Causal Dynamical Triangulations

    CERN Document Server

    Mielczarek, Jakub

    2015-01-01

    The four dimensional Causal Dynamical Triangulations (CDT) approach to quantum gravity is already more than ten years old theory with numerous unprecedented predictions such as non-trivial phase structure of gravitational field and dimensional running. Here, we discuss possible empirical consequences of CDT derived based on the two features of the approach mentioned above. A possibility of using both astrophysical and cosmological observations to test CDT is discussed. We show that scenarios which can be ruled out at the empirical level exist.

  2. Influência dos agentes clareadores e um refrigerante a base de cola na microdureza do esmalte dental e a ação da saliva na superfície tratada = Influence of bleaching agents and a carbonated soft drink on dental enamel microhardness as well as the artificial saliva effect on the treated surface

    Directory of Open Access Journals (Sweden)

    Araújo, Rodrigo Maximo de

    2006-01-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos de três agentes clareadores e uma bebida carbonatada, à base de cola, sobre a microdureza do esmalte dental, assim como os efeitos da saliva artificial sobre o esmalte tratado com estes agentes. Foram utilizados quarenta dentes incisivos bovinos embutidos em resina acrílica. As amostras foram avaliadas em microdurômetro (Future Tech FM 700 após a divisão em quatro grupos, uma leitura inicial da microdureza serviu como controle do experimento: Grupo 1: peróxido de carbamida a 10% (Whiteness Perfect – FGM; Grupo 2: refrigerante Coca-Cola; Grupo 3: peróxido de carbamida a 37% (Whiteness Super – FGM; Grupo 4: peróxido de hidrogênio a 35% (Whiteness HP – FGM. Os dados foram submetidos aos testes estatísticos ANOVA e Tukey. Conclui-se que os agentes clareadores não diminuíram a microdureza do esmalte; a exposição à Coca-Cola diminuiu significantemente a microdureza do esmalte; o tempo de exposição aos agentes foi significante apenas para a Coca- Cola; o armazenamento em saliva aumentou a microdureza do esmalte exposto ao peróxido de carbamida a 37%; à Coca-Cola e ao peróxido de hidrogênio à 35%

  3. Velocity Requirements for Causality Violation

    Science.gov (United States)

    Modanese, Giovanni

    We re-examine the "Regge-Tolman paradox" with reference to some recent experimental results. It is straightforward to find a formula for the velocity v of the moving system required to produce causality violation. This formula typically yields a velocity very close to the speed of light (for instance, v/c > 0.97 for X-shaped microwaves), which raises some doubts about the real physical observability of the violations. We then compute the velocity requirement introducing a delay between the reception of the primary signal and the emission of the secondary. It turns out that in principle for any delay it is possible to find moving observers able to produce active causal violation. This is mathematically due to the singularity of the Lorentz transformations for β →1. For a realistic delay due to the propagation of a luminal precursor, we find that causality violations in the reported experiments are still more unlikely (v/c > 0.989), and even in the hypothesis that the superluminal propagation velocity goes to infinity, the velocity requirement is bounded by v/c > 0.62. We also prove that if two oscopic bodies exchange energy and momentum through superluminal signals, then the swap of signal source and target is incompatible with the Lorentz transformations; therefore it is not possible to distinguish between source and target, even with reference to a definite reference frame.

  4. 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...

  5. Identificação de agentes infecciosos pulmonares em autópsias de pacientes com a síndrome da imunodeficiência adquirida Identification of infectious agents in the lungs in autopsies of patients with acquired immunodeficiency syndrome

    Directory of Open Access Journals (Sweden)

    Sanivia Aparecida de Lima Pereira

    2002-12-01

    Full Text Available As afecções pulmonares são freqüentes em indivíduos infectados pelo vírus da imunodeficiência humana. Neste trabalho, procurou-se identificar através de histoquímica e imunohistoquímica, agentes infecciosos nos pulmões de indivíduos portadores da síndrome da imunodeficiência adquirida (SIDA, autopsiados entre março de 1990 e julho de 2000 na FMTM. Fragmentos de pulmão de 40 indivíduos com SIDA autopsiados foram analisados histologicamente. Foram identificados agentes infecciosos em 34 (85% casos dos 40 analisados, sendo que bactérias foram encontradas em 22 (55% casos. Entre os agentes fúngicos o Pneumocystis carinii foi encontrado em oito (19,1% casos; Cryptococcus sp em quatro (9,5%, Histoplasma sp em dois (4,8% e Candida sp em um (2,4% caso. Detectou-se também associação entre Pneumocystis carinii, Citomegalovirus e Cryptococcus sp; CMV e Toxoplasma gondii. Em cinco casos, Candida sp, CMV e Pneumocystis carinii estiveram associados a bactérias. Entre as infecções não bacterianas, os fungos foram os agentes infecciosos mais isolados dos pulmões em autópsias de indivíduos com SIDA, sendo o Pneumocystis carinii o mais freqüente.Lung diseases are frequently observed in individuals infected with HIV. The aim of this study was to identify infectious agents in the lungs in the autopsied individuals with AIDS performed between march 1990 and july 2000 at the school of medicine (Uberaba- Brazil, using histochemical and immunohistochemical techniques. Analysis was made on lungs obtained from 40 individuals with AIDS. Infectious agents were observed in 34 (85% cases of the 40 analyzed. Regarding fungis, Pneumocystis carinii was found in 8 (19.1%cases; Cryptococcus sp in 4 (9.5%cases, Histoplasma sp in 2 (4.8%cases and Candida sp in 1 (2.4%case. Association of Pneumocystis carinii, Citomegalovirus and Cryptococcus sp, was observed in one case, and in another, the association of CMV, and Toxoplasma gondii. There were 5 cases

  6. The key role of causal explanation in the climate change issue

    Directory of Open Access Journals (Sweden)

    Francesca Pongiglione

    2012-06-01

    Full Text Available The basis for adoption of pro-environment behaviour is the understanding of causal passages within climate dynamics. The understanding of the causes of climate change is necessary in order to be able to take mitigation actions  (the subject needs to be aware of his role as a causal agent. Conversely, the understanding of the consequences of climate change is essential in motivating action (the subject must be aware of the risks caused by it in order to prevent them. The case of ozone depletion confirms this view: the understanding of its causal dynamics played a determining role in people’s behavioural response.

  7. Atividades de controle do dengue na visão de seus agentes e da população atendida, São José do Rio Preto, São Paulo, Brasil Dengue control as viewed by agents and the target population in São José do Rio Preto, São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Virgínia Baglini

    2005-08-01

    Full Text Available O objetivo foi identificar, no contexto da atuação dos agentes responsáveis pelo controle do dengue e na sua relação com moradores, situações vivenciadas no dia-a-dia de suas funções. Realizou-se estudo transversal com aplicação de questionários à população dos agentes de controle de vetores (ACV, à dos agentes comunitários de saúde (ACS e a uma amostra de mulheres. As respostas dadas pelos agentes foram agrupadas nos âmbitos do trabalho, particular e coletivo. As mulheres foram abordadas sobre a relação mantida com os agentes. As dificuldades citadas nos âmbitos particular e trabalho pelos ACV diferiram das citadas pelos ACS. No coletivo foram coincidentes e mostraram que ambos não estão preparados para lidar com estas questões. Das mulheres entrevistadas, 87,0% afirmaram estar bem ou muito bem informadas sobre dengue, 84,0% afirmaram que os trabalhos dos agentes ajudam sempre e 54,0% apontaram como dificuldade o horário impróprio da visita realizada pelo agente. Identificou-se a necessidade de um novo profissional que reconheça e respeite as particularidades dos locais onde atua e desenvolva suas atividades de forma integrada às questões sócio-ambientais da comunidade.The aim of this article was to identify daily situations experienced by dengue control agents in their relationship to local residents. A cross-sectional study applied questionnaires among vector control agents, community health workers, and a sample of local women. The answers by the dengue control agents and community health workers were grouped in the categories of work, private life, and community. The women were asked about the relationship with the vector control and community health workers. The difficulties cited in the private and work areas by the vector control agents were different from those reported by community health workers. At the community level they coincided and showed that neither group is adequately prepared to deal with these

  8. Shear bond strength after dentin bleaching with 10% carbamide peroxide agents Resistência ao cisalhamento da dentina após clareamento com peróxido de carbamida a 10%

    Directory of Open Access Journals (Sweden)

    Roberta Tarkany Basting

    2004-06-01

    Full Text Available This in vitro study evaluated the shear bond strength (SBS of dentin treated with two 10% carbamide peroxide bleaching agents 15 days after bleaching and storage in artificial saliva. Dentin fragments were randomly divided into 3 groups (n = 20 for the treatment with the two different bleaching agents (Rembrandt 10% or Opalescence 10% or with a placebo agent, applied to the tooth surface for 8 hours a day. During the remaining time, the specimens were stored in artificial saliva. After 42 days, the fragments were stored in artificial saliva for 14 days. Another group (n = 20 was exposed to distilled and deionized water for 56 days. An adhesive system and microhybrid composite resin were used to prepare specimens for the SBS test. SBS tests were performed and the fractured surfaces were visually examined using a stereoscope at 30 X magnification. The analysis of variance (ANOVA and SIDAK tests showed higher SBS values for dentin treated with Opalescence 10% than for dentin treated with Rembrandt 10% or placebo. Groups treated with Rembrandt 10%, Opalescence 10% or placebo did not differ from the group treated with distilled and deionized water. Ten percent carbamide peroxide agents or a placebo agent caused no differences in SBS of dentin after 15 days of storage in artificial saliva.Este estudo in vitro avaliou a resistência ao cisalhamento da dentina submetida ao tratamento com dois agentes clareadores contendo peróxido de carbamida a 10% depois de 15 dias de clareamento e armazenagem em saliva artificial. Fragmentos de dentina foram aleatoriamente distribuídos em 3 grupos (n = 20 para receber o tratamento com dois diferentes agentes clareadores (Rembrandt a 10% ou Opalescence a 10% ou com um agente placebo, aplicados na superfície dental por 8 horas diárias. No restante do tempo, os espécimens permaneceram imersos em saliva artificial. Após o tratamento por 42 dias, os fragmentos foram armazenados em saliva artificial por 14 dias. Outro

  9. 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...

  10. 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...

  11. Space and time in perceptual causality.

    Science.gov (United States)

    Straube, Benjamin; Chatterjee, Anjan

    2010-01-01

    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. PMID:20463866

  12. 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.

  13. 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.

  14. 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

  15. Causal structure and hierarchies of models.

    Science.gov (United States)

    Hoover, Kevin D

    2012-12-01

    Economics prefers complete explanations: general over partial equilibrium, microfoundational over aggregate. Similarly, probabilistic accounts of causation frequently prefer greater detail to less as in typical resolutions of Simpson's paradox. Strategies of causal refinement equally aim to distinguish direct from indirect causes. Yet, there are countervailing practices in economics. Representative-agent models aim to capture economic motivation but not to reduce the level of aggregation. Small structural vector-autoregression and dynamic stochastic general-equilibrium models are practically preferred to larger ones. The distinction between exogenous and endogenous variables suggests partitioning the world into distinct subsystems. The tension in these practices is addressed within a structural account of causation inspired by the work of Herbert Simon's, which defines cause with reference to complete systems adapted to deal with incomplete systems and piecemeal evidence. The focus is on understanding the constraints that a structural account of causation places on the freedom to model complex or lower-order systems as simpler or higher-order systems and on to what degree piecemeal evidence can be incorporated into a structural account.

  16. Uso de bovinos e de ovinos como agentes de controle da vegetação nativa sob três populações de eucalipto

    Directory of Open Access Journals (Sweden)

    Alexandre Costa Varella

    1999-02-01

    Full Text Available O objetivo deste trabalho foi avaliar cinco sistemas de controle da vegetação nativa e os danos provocados por bovinos e ovinos em três populações de eucalipto. O delineamento experimental foi em parcelas subdivididas, com dois blocos completos. Os tratamentos foram: a três densidades de Eucalyptus saligna Smith. (204, 400 e 816 árvores/ha nas parcelas principais e b cinco sistemas de controle da vegetação nativa (sem controle, herbicida pré-emergente, herbicidas pré e pós-emergentes, pastejo com bovinos e com ovinos nas subparcelas. O pastejo com bovinos ou ovinos foi mais eficiente na redução da vegetação nativa que nos demais tratamentos. Os bovinos danificaram mais as árvores que os ovinos. Existe estreita relação entre a altura das mudas de eucalipto e os danos causados pelos bovinos e ovinos no momento da introdução destes animais no sub-bosque.

  17. O bibliotecário como agente socializador na disseminação da informação sobre Meio Ambiente: relato de experiência

    Directory of Open Access Journals (Sweden)

    Maritza Silveira Martins

    2006-04-01

    Full Text Available A preocupação com o meio ambiente está inserida em várias áreas do conhecimento e presente no cotidiano de diferentes tipos de profissionais. Fornecer informações, com o intuito de alcançar um comportamento ecologicamente correto, gerandopensamentos críticos e atitudes conscientes com relação ao ecossistema, também são tarefas do profissional bibliotecário.Colocar em prática tais atividades biblioteconômicas, através de métodos não-convencionais, foi o fator motivador que impulsionou o desenvolvimento deste trabalho, no qual crianças da 1º a 4º série da Escola Barão de Cerro Largo, localizada no município de Rio Grande, RS, pudessem participar de uma Trilha Ecológica e visualizar a natureza devastada e a natureza protegida, através da montagem de cenários e da narração de uma história infantil.

  18. À descoberta da sociedade civil regional: Os parceiros sociais, agentes das políticas regionais financiadas pela União Europeia

    Directory of Open Access Journals (Sweden)

    Elisabeth Dupoirier

    2012-10-01

    Full Text Available A presença de interlocutores da sociedade civil junto da acção pública é estimulada pelas normas europeias, que reforçam o papel dos “parceiros sociais” nos vários patamares da governação. Para as regiões francesas, a possibilidade de associar às suas políticas a expertise e representatividade social dos grupos de interesse constitui um meio importante de legitimação e eficácia. O contexto regional é, todavia, pouco atractivo para os representantes da sociedade civil. Estes, com dificuldade em conciliar posições nos territórios e inibidos pela complexidade dos programas comunitários, preferem apostar no percurso institucional tradicional, privilegiando o relacionamento com o Estado e os departamentos. As regiões, por outro lado, vêem a nível territorial os parceiros sociais virar-se mais para as aglomerações urbanas.

  19. 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

  20. 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...

  1. Identifying Causal Effects with Computer Algebra

    CERN Document Server

    García-Puente, Luis David; Sullivant, Seth

    2010-01-01

    The long-standing identification problem for causal effects in graphical models has many partial results but lacks a systematic study. We show how computer algebra can be used to either prove that a causal effect can be identified, generically identified, or show that the effect is not generically identifiable. We report on the results of our computations for linear structural equation models, where we determine precisely which causal effects are generically identifiable for all graphs on three and four vertices.

  2. 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

  3. 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

  4. As escolhas públicas orçamentárias federais no PPA 2008-2011: uma análise da perspectiva do modelo principal-agente

    Directory of Open Access Journals (Sweden)

    Giovanni Pacelli Carvalho Lustosa da Costa

    2013-10-01

    Full Text Available O objetivo deste estudo é analisar o comportamento assumido pelo Executivo e pelo Legislativo durante a gestão do PPA 2008-2011 da perspectiva do modelo principal-agente. Por meio da aplicação dos testes de Friedman, Kendall e Spearman e tendo como objeto empírico todos os programas constantes no PPA 2008-2011, observou-se que entre 2008 e 2011: as etapas de Elaboração e de Execução Orçamentária e Financeira da Lei Orçamentária Anual, cujo ator principal é o Poder Executivo, apresentaram concordância muito forte; enquanto a etapa de Discussão, Votação e Aprovação, cujo ator principal é o Poder Legislativo, apresentou concordância moderada. Quando se considerou a interação no mesmo ciclo entre todas as etapas, a concordância foi menor. Além disso, como resultado mais expressivo do estudo, identificou-se que a relação externa (entre governo e cidadãos possui concordância maior que a relação interna (entre políticos e burocratas.

  5. Extrusão de compósitos de PP com fibras curtas de coco: efeito da temperatura e agentes de acoplamento Extrusion of PP composites with short coir fibers: effect of temperature and coupling agents

    Directory of Open Access Journals (Sweden)

    Evelise F. Santos

    2010-09-01

    Full Text Available Compósitos de PP com fibras curtas de coco foram preparados em extrusora, com dois perfis de temperatura, visando avaliar o efeito compatibilizante de PP modificado com vinilalcoxisilano e com anidrido maleico. Foi verificado que os dois agentes de acoplamento melhoraram o módulo elástico, a tensão máxima e a resistência à absorção de água quando os materiais foram processados utilizando-se um perfil de temperaturas mais elevadas. A morfologia dos compósitos também ficou mais homogênea na presença dos agentes de acoplamento, especialmente naqueles processados na temperatura mais alta. Esses resultados indicam que a temperatura é uma variável fundamental no estabelecimento das interações envolvendo os processos de compatibilização.PP composites filled with coir short fibers were prepared in an extruder using two temperature profiles. The objective was to evaluate the compatibilizing effect of PP modified with vinylsilane and with maleic anhydride. Both coupling agents improved elastic modulus, tensile strength and water absorption resistance when the materials were processed at the highest temperature profile. The composite morphology was more homogeneous in the presence of the coupling agents, mainly in the composites processed at the highest temperatures. These results indicate that temperature is a key variable for the establishment of the interactions involved in the coupling processes.

  6. 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...

  7. Efetividade de programa de agentes comunitários na promoção da saúde bucal Efectividad del programa de agentes comunitarios en la promoción de la salud bucal Effectiveness of a community health worker program on oral health promotion

    OpenAIRE

    Paulo Frazão; Débora Marques

    2009-01-01

    OBJETIVO:Avaliar mudanças em conhecimentos, atitudes e acesso/utilização de serviços odontológicos decorrentes de um programa de promoção da saúde bucal com agentes comunitários de saúde. MÉTODOS:Um projeto de capacitação combinando ensino-aprendizagem, apoio e supervisão, foi desenvolvido entre os meses de julho de 2003 a agosto de 2004. As mudanças foram avaliadas por meio de entrevistas estruturadas em que participaram 36 agentes comunitários de saúde e uma amostra de 91 mulheres e mães, r...

  8. 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.

  9. Influência do agente de cloração do catalisador à base de veodímio e da razão molar Cl: Nd na polimerização do butadieno Influence of the chlorinating agent of neodymium based catalysts and Cl: Nd molar ratio on butadiene polymerization

    Directory of Open Access Journals (Sweden)

    Cintia N. Ferreira

    2009-06-01

    Full Text Available Neste trabalho foi utilizado um sistema catalítico composto por hidreto de diisobutilalumínio (DIBAH, versatato de neodímio (NdV e um agente de cloração para avaliar a influência da fonte de cloro e da razão molar Cl:Nd nas características da reação de polimerização (conversão e constante de velocidade de propagação e do polibutadieno (massa molecular e microestrutura. Os agentes de cloração estudados foram cloreto de t-butila (t-BuCl, sesquicloreto de etilalumínio (EASC e cloreto de dietilalumínio (DEAC. As razões molares Cl:Nd utilizadas foram: 1:1, 3:1 e 5:1 para o t-BuCl; 0,5:1, 1:1 e 3:1 para o EASC e 1:1, 1,5:1, 3:1 e 5:1 para o DEAC. Foi observada a existência, para cada agente de cloração, de um valor ótimo de razão molar Cl:Nd para o qual a conversão foi máxima. O DEAC apresentou uma maior conversão em relação aos outros agentes de cloração; em contrapartida, o t-BuCl produziu polibutadienos com maior teor de unidades 1,4-cis e maior massa molecular (n e wIn this work catalyst systems consisting of diisobutylaluminium hydride (DIBAH, neodymium versatate (NdV and a chlorinating agent were employed to study the influence of the chloride source and Cl:Nd molar ratio on 1,3-butadiene polymerization and polybutadiene's characteristics (molecular weight and microstructure. The chloride sources studied were t-butyl chloride, ethylaluminium sesquichloride (EASC and diethylaluminium chloride (DEAC. The Cl:Nd molar ratios used were 1:1, 3:1 e 5:1 for t-butyl chloride; 0.5:1, 1:1 and 3:1 for EASC and 1:1, 1.5:1, 3:1 and 5:1 for DEAC. A maximum value of Cl:Nd molar ratio exists. Moreover, DEAC showed to be more reactive than EASC and t-BuCl but t-BuCl produced higher molecular weight and cis-1,4 units contents.

  10. O equívoco no discurso da inclusão: o funcionamento do conceito de diferença no depoimento de agentes educacionais The mistake in the inclusive discourse: the functioning of the concept of difference within the educational agents' statements

    Directory of Open Access Journals (Sweden)

    Juliana Santana Cavallari

    2010-01-01

    Full Text Available Este estudo se propõe a analisar o modo como o discurso da inclusão produz efeitos de verdade em nosso meio sócio-histórico, ao evocar outros domínios discursivos. Ancorada na perspectiva discursiva, perpassada pela psicanálise lacaniana, foram destacadas algumas regularidades nos depoimentos proferidos por agentes educacionais, durante palestras realizadas em um congresso sobre "inclusão e diversidade". Partindo da questão: como os conceitos de inclusão e diferença colocam os dizeres de agentes educacionais em funcionamento?, a análise do corpus discursivo evidenciou a aparente "necessidade" de aplicação do discurso da inclusão como eliminador das diferenças (físicas ou não, o que, imaginariamente, possibilitaria uma prática pedagógica mais justa e igualitária. Trata-se, portanto, de um equívoco de ordem ideológica, tendo em vista que a prática discursiva em questão não visa a incluir as diferenças ou tratá-las de modo singular, mas a criar identidades fixas, conservadoras e repetitivas.The purpose of this study is to analyze the way the discourse upon inclusive practices produces some effects of truth within our social and historical environment, by evoking other discursive domains. Through a discursive perspective, affected by the psychoanalysis, some regularities enunciated by educational agents, during speeches given at a Congress concerning inclusion and diversity, were pointed out. The analysis of the data was based on the following question: to what extent the concepts of difference and inclusion make the talk of educational agents meaningful? The results have stressed the "necessity" felt by the educational agents of applying the inclusive discourse to promote a fair and equal pedagogical practice. Taking into account that this kind of practice tends not to treat the differences in a singular way, it's possible to state that repetitive, traditional and permanent identities have been built within the

  11. 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...

  12. Bioprospecting endophytic bacteria for biological control of coffee leaf rust Bioprospecção de bactérias endofíticas como agentes de biocontrole da ferrugem do cafeeiro

    Directory of Open Access Journals (Sweden)

    Humberto Franco Shiomi

    2006-02-01

    Full Text Available Suppression of plant diseases due to the action of endophytic microorganisms has been demonstrated in several pathosystems. Experiments under controlled conditions involving endophytic bacteria isolated from leaves and branches of Coffea arabica L and Coffea robusta L were conducted with the objective of evaluating the inhibition of germination of Hemileia vastatrix Berk. & Br., race II, urediniospores and the control of coffee leaf rust development in tests with leaf discs, detached leaves, and on potted seedling of cv. Mundo Novo. The endophytic bacterial isolates tested proved to be effective in inhibiting urediniospore germination and/or rust development, with values above 50%, although the results obtained in urediniospore germination tests were inferior to the treatment with fungicide propiconazole. Endophytic isolates TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa, and TF7-IIa, demonstrated better coffee leaf rust control in leaf discs, detached leaves, and coffee plant tests. The endophytic isolates TG4-Ia and TF9-Ia were identified as Bacillus lentimorbus Dutky and Bacillus cereus Frank. & Frank., respectively. Some endophytic bacterial isolates were effective in controlling the coffee leaf rust, although some increased the severity of the disease. Even though a relatively small number of endophytic bacteria were tested, promising results were obtained regarding the efficiency of coffee leaf rust biocontrol. These selected agents appears to be an alternative for future replacement of chemical fungicide.Supressão de doenças de plantas por microrganismos endofíticos tem sido demonstrada em diversos patossistemas. Neste trabalho foram selecionados isolados de bactérias endofíticas de folhas e ramos de cafeeiro com potencial para o controle biológico da ferrugem do cafeeiro, pois é conhecido que esses microrganismos podem possuir essa característica. Bactérias endofíticas isoladas previamente de folhas e ramos de Coffea arabica L e Coffea

  13. The gut microbiota and obesity: from correlation to causality.

    Science.gov (United States)

    Zhao, Liping

    2013-09-01

    The gut microbiota has been linked with chronic diseases such as obesity in humans. However, the demonstration of causality between constituents of the microbiota and specific diseases remains an important challenge in the field. In this Opinion article, using Koch's postulates as a conceptual framework, I explore the chain of causation from alterations in the gut microbiota, particularly of the endotoxin-producing members, to the development of obesity in both rodents and humans. I then propose a strategy for identifying the causative agents of obesity in the human microbiota through a combination of microbiome-wide association studies, mechanistic analysis of host responses and the reproduction of diseases in gnotobiotic animals.

  14. 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…

  15. Um projeto de intervenção social visto pelos seus agentes: estudo psicossocial do Programa de Saúde da Família

    Directory of Open Access Journals (Sweden)

    Ana Maria Blanques

    2010-01-01

    Full Text Available O Programa de Saúde da Família (PSF foi escolhido como objeto deste estudo por ser um projeto de intervenção social que pretende promover maior autonomia da população para resolver problemas relativos à saúde no território. O material obtido em entrevistas com os profissionais foi analisado por meio de categorias agrupadas em dois blocos temáticos: concepção do trabalho - aquelas que se referem às atividades, e de sujeito - em que se reúnem as ideias sobre as pessoas envolvidas. Os conteúdos revelam que o programa não atinge as mudanças previstas. O conceito de território é incipiente, a participação é precária e as doenças se mantêm em lugar privilegiado. As pessoas da população são referidas num conjunto que é caracterizado por faltas, carências, necessidades e, em muitos casos, são identificadas aos próprios entrevistados. A ajuda mobiliza as ações e é o eixo a partir do qual os atores compreendem sua própria atuação.

  16. Stress ocupacional em profissionais de segurança pública: um estudo com militares da Guarda Nacional Republicana Occupational stress in professionals of public security: a study with military agents of the Republican National Guard

    Directory of Open Access Journals (Sweden)

    Jorge M. P. Afonso

    2009-01-01

    Full Text Available Este trabalho analisa o "stress" ocupacional em 95 militares da Guarda Nacional Republicana Portuguesa. Para tal, utilizámos um protocolo de avaliação com medidas do "stress" global, "burnout", "coping" proactivo, comprometimento organizacional, satisfação com a vida e satisfação/realização profissional. Os indicadores de fidelidade e validade dos instrumentos foram muito aceitáveis. Os resultados de "burnout" por dimensão apontaram níveis apreciáveis de exaustão emocional (12%, seguidos do cinismo (10% e da baixa eficácia profissional (8% (mas nenhum participante registou valores de "burnout" nas três dimensões, em simultâneo, observando-se também variáveis distintas na predição destas três áreas. A análise discriminante entre subgrupos da amostra permitiu verificar dois aspectos principais: (a menores níveis de comprometimento organizacional e maior utilização de "coping" proactivo nos militares mais novos e/ou inexperientes e (b maior desejo de abandonar o emprego/trabalho bem como maior cinismo parecem identificar os profissionais mais velhos e/ou mais experientes. No final, os autores discutem a importância de a investigação futura analisar os efeitos da maior tendência para o cinismo com o aumento da idade dos participantes e os efeitos do menor comprometimento organizacional por parte dos mais novos em termos da sua eficácia profissional.This work analyzes occupational stress in 95 Portuguese military agents of the Republican National Guard. We applied an evaluation protocol with measures of global stress, burnout, proactive coping, organizational commitment, satisfaction with life, and professional satisfaction/accomplishment. The fidelity and validity results of the instruments were very acceptable. The results of burnout pointed out a remarkable level of emotional exhaustion (12% followed by cynicism (10% and low professional effectiveness (8% (but we have not found any participant with burnout values

  17. 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...

  18. Causal Indicator Models: Identification, Estimation, and Testing

    Science.gov (United States)

    Bollen, Kenneth A.; Davis, Walter R.

    2009-01-01

    We discuss the identification, estimation, and testing of structural equation models that have causal indicators. We first provide 2 rules of identification that are particularly helpful in models with causal indicators--the 2C emitted paths rule and the exogenous X rule. We demonstrate how these rules can help us distinguish identified from…

  19. Causal Moderation Analysis Using Propensity Score Methods

    Science.gov (United States)

    Dong, Nianbo

    2012-01-01

    This paper is based on previous studies in applying propensity score methods to study multiple treatment variables to examine the causal moderator effect. The propensity score methods will be demonstrated in a case study to examine the causal moderator effect, where the moderators are categorical and continuous variables. Moderation analysis is an…

  20. 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

  1. On the spectral formulation of Granger causality.

    Science.gov (United States)

    Chicharro, D

    2011-12-01

    Spectral measures of causality are used to explore the role of different rhythms in the causal connectivity between brain regions. We study several spectral measures related to Granger causality, comprising the bivariate and conditional Geweke measures, the directed transfer function, and the partial directed coherence. We derive the formulation of dependence and causality in the spectral domain from the more general formulation in the information-theory framework. We argue that the transfer entropy, the most general measure derived from the concept of Granger causality, lacks a spectral representation in terms of only the processes associated with the recorded signals. For all the spectral measures we show how they are related to mutual information rates when explicitly considering the parametric autoregressive representation of the processes. In this way we express the conditional Geweke spectral measure in terms of a multiple coherence involving innovation variables inherent to the autoregressive representation. We also link partial directed coherence with Sims' criterion of causality. Given our results, we discuss the causal interpretation of the spectral measures related to Granger causality and stress the necessity to explicitly consider their specific formulation based on modeling the signals as linear Gaussian stationary autoregressive processes.

  2. 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.

  3. Causally pathological spacetimes are physically relevant

    CERN Document Server

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

    2005-01-01

    We argue that in the context of string theory, the usual restriction to globally hyperbolic spacetimes should be considerably relaxed. We exhibit an example of a spacetime which only satisfies the causal condition, and so is arbitrarily close to admitting closed causal curves, but which has a well-behaved dual description, free of paradoxes.

  4. Structural intervention distance for evaluating causal graphs

    DEFF Research Database (Denmark)

    Peters, Jonas; Bühlmann, Peter

    2015-01-01

    Causal inference relies on the structure of a graph, often a directed acyclic graph (DAG). Different graphs may result in different causal inference statements and different intervention distributions. To quantify such differences, we propose a (pre-)metric between DAGs, the structural interventi...... implementation with software code available on the first author's home page....

  5. 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…

  6. 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.

  7. Causal random geometry from stochastic quantization

    DEFF Research Database (Denmark)

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

    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...... the sum over topologies. Interestingly, the generally fictitious stochastic time corresponds to proper time on the geometries...

  8. Comunicação no Programa Saúde da Família: o agente de saúde como elo integrador entre a equipe e a comunidade Communication in the Family Health Program: the health agent as an integrating link between the team and the community

    Directory of Open Access Journals (Sweden)

    Andréia dos Santos Cardoso

    2010-06-01

    Full Text Available Este estudo é parte do projeto "Avaliação da Estratégia da Saúde da Família no Município do Rio de Janeiro", desenvolvido na Universidade Estácio de Sá com apoio do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq. Buscou identificar e analisar a percepção dos agentes comunitários de saúde (ACS quanto aos seus principais interlocutores, o grau de impacto destes interlocutores e as formas de comunicação predominantes no seu processo de trabalho. É um estudo descritivo, de abordagem qualitativa, com base em categorias teórico-metodológicas da educação popular e do modelo de comunicação do mercado simbólico. Os dados foram coletados em quatro equipes, de duas unidades do Programa Saúde da Família. Os mapas de comunicação elaborados com os ACS identificam o grupo de apoio técnico, a equipe técnica, os próprios ACS e os moradores antigos da comunidade como seus principais interlocutores. A comunicação com os demais profissionais da equipe é percebida de forma predominantemente verticalizada e com traços de autoritarismo. Os resultados revelam a importância de ampliação do diálogo e da negociação na comunicação estabelecida no interior da equipe e com a comunidade.This study is part of the project Evaluation of the Family Health Strategy in Rio de Janeiro, developed at Estácio de Sá University with support of the National Advice of Scientific and Technological Development (CNPq. The study aimed to identify and analyze the perception of the health communitarian agents (HCA about their main interlocutors, the impact of these interlocutors and the predominant communication forms in their work process. It is a descriptive study, with a qualitative approach, based on theoretical-methodological categories of the popular education and the symbolic market communication model. The data was collected in four teams of the Family Health Program. The results show the communication maps elaborated

  9. Trabalhador de enfermagem: agente colaborador no cumprimento da missão institucional Trabajador de enfermería: agente colaborador del cumplimento de la misión institucional Worker of nursing: collaborating agent in the execution of the institutional mission

    Directory of Open Access Journals (Sweden)

    Diana Cecagno

    2005-02-01

    Full Text Available Este estudo teve como propósito investigar estratégias que podem ser utilizadas, pelas instituições de saúde, sob ao olhar do enfermeiro, para motivar/valorizar e promover a capacitação do trabalhador de enfermagem, enquanto agente colaborador da instituição em busca do cumprimento de sua missão. Para a concretização do mesmo, investimos em uma metodologia qualitativa, descritiva e exploratória, cujo instrumento de pesquisa, semi-estruturado, foi aplicado a 15 enfermeiros, sendo garantido, aos mesmos, os preceitos éticos e legais cabíveis nesse estudo. Ao concluirmos este estudo constatamos que as principais estratégias que podem ser utilizadas, sob a ótica do enfermeiro, para motivar/valorizar e promover a capacitação do trabalhador de enfermagem, dizem respeito à necessidade de diálogo e a promoção do crescimento profissional.Esto estudio tuve como propósito investigar las estratégicas que puede usarse, pelas instituciones de salud, conforme la mirada de la enfermera, para motivar/valorizar y promover la capacitación del trabajador de enfermería, mientras agente colaborador de la institución en busca del cumplimento de misión. Para la concretización del mismo, nosotros invertimos en una metodología de carácter cualitativo, descriptivo y exploratorio cuyo instrumento de pesquisa, semi-estructurado, fue aplicado a 15 enfermeras, siendo garantido, al los mismos, los mandatos éticos y legales caviléis en ese estudio. Al concluirmos este estudio verificamos que las estrategias principales que pueden usarse, pelas instituciones de salud, conforme la mirada de los enfermeros, para el motivar/valorizar y promover la capacitación del trabajador de enfermería, dicen repecho a la necesidad del diálogo y la promoción del crecimiento profesional.The study aimed to investigate the strategy that can be used by health institutions, with respect to the nurse's optics, to motivate/value and to promote the nursing worker

  10. Causality, Bell's theorem, and Ontic Definiteness

    CERN Document Server

    Henson, Joe

    2011-01-01

    Bell's theorem shows that the reasonable relativistic causal principle known as "local causality" is not compatible with the predictions of quantum mechanics. It is not possible maintain a satisfying causal principle of this type while dropping any of the better-known assumptions of Bell's theorem. However, another assumption of Bell's theorem is the use of classical logic. One part of this assumption is the principle of "ontic definiteness", that is, that it must in principle be possible to assign definite truth values to all propositions treated in the theory. Once the logical setting is clarified somewhat, it can be seen that rejecting this principle does not in any way undermine the type of causal principle used by Bell. Without ontic definiteness, the deterministic causal condition known as Einstein Locality succeeds in banning superluminal influence (including signalling) whilst allowing correlations that violate Bell's inequalities. Objections to altering logic, and the consequences for operational and...

  11. 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.

  12. 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.

  13. On the spectral dimension of causal triangulations

    CERN Document Server

    Durhuus, Bergfinnur; Wheater, John F

    2009-01-01

    We introduce an ensemble of infinite causal triangulations, called the uniform infinite causal triangulation, and show that it is equivalent to an ensemble of infinite trees, the uniform infinite planar tree. It is proved that in both cases the Hausdorff dimension almost surely equals 2. The infinite causal triangulations are shown to be almost surely recurrent or, equivalently, their spectral dimension is almost surely less than or equal to 2. We also establish that for certain reduced versions of the infinite causal triangulations the spectral dimension equals 2 both for the ensemble average and almost surely. The triangulation ensemble we consider is equivalent to the causal dynamical triangulation model of two-dimensional quantum gravity and therefore our results apply to that model.

  14. 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

  15. Comparação da superfície do esmalte antes e após clareamento com dois diferentes agentes: estudo clínico

    Directory of Open Access Journals (Sweden)

    Virgínia Teichmann Espina

    2008-01-01

    Full Text Available The purpose of this study was to compare of enamel surface before and after bleaching with two different agents. Twenty subjects were selected and divided in two groups: Group 1- treated with the night guard vital bleaching using 10% carbamide peroxide (Whiteness Perfect and Group 2- treated with the in-offi ce technique using 35% hydrogen peroxide (Whiteness HP. Epoxi resin replicas obtained from the maxillary central incisors, before, immediately after and thirty days after the bleaching procedure. All replicas were photography in scanning electron microscopy and examined for one expert and blind examiner taken in scores: 1- surface without alteration 2- surface with alteration. This study demonstrated that bleaching treatment using both agents causes effect on namel surface, but these are partially reverted in thirty days.

  16. Causal systems categories: differences in novice and expert categorization of causal phenomena.

    Science.gov (United States)

    Rottman, Benjamin M; Gentner, Dedre; Goldwater, Micah B

    2012-07-01

    We investigated the understanding of causal systems categories--categories defined by common causal structure rather than by common domain content--among college students. We asked students who were either novices or experts in the physical sciences to sort descriptions of real-world phenomena that varied in their causal structure (e.g., negative feedback vs. causal chain) and in their content domain (e.g., economics vs. biology). Our hypothesis was that there would be a shift from domain-based sorting to causal sorting with increasing expertise in the relevant domains. This prediction was borne out: the novice groups sorted primarily by domain and the expert group sorted by causal category. These results suggest that science training facilitates insight about causal structures.

  17. Spread of entanglement and causality

    Science.gov (United States)

    Casini, Horacio; Liu, Hong; Mezei, Márk

    2016-07-01

    We investigate causality constraints on the time evolution of entanglement entropy after a global quench in relativistic theories. We first provide a general proof that the so-called tsunami velocity is bounded by the speed of light. We then generalize the free particle streaming model of [1] to general dimensions and to an arbitrary entanglement pattern of the initial state. In more than two spacetime dimensions the spread of entanglement in these models is highly sensitive to the initial entanglement pattern, but we are able to prove an upper bound on the normalized rate of growth of entanglement entropy, and hence the tsunami velocity. The bound is smaller than what one gets for quenches in holographic theories, which highlights the importance of interactions in the spread of entanglement in many-body systems. We propose an interacting model which we believe provides an upper bound on the spread of entanglement for interacting relativistic theories. In two spacetime dimensions with multiple intervals, this model and its variations are able to reproduce intricate results exhibited by holographic theories for a significant part of the parameter space. For higher dimensions, the model bounds the tsunami velocity at the speed of light. Finally, we construct a geometric model for entanglement propagation based on a tensor network construction for global quenches.

  18. Spread of entanglement and causality

    CERN Document Server

    Casini, Horacio; Mezei, Márk

    2015-01-01

    We investigate causality constraints on the time evolution of entanglement entropy after a global quench in relativistic theories. We first provide a general proof that the so-called tsunami velocity is bounded by the speed of light. We then generalize the free particle streaming model of arXiv:cond-mat/0503393 to general dimensions and to an arbitrary entanglement pattern of the initial state. In more than two spacetime dimensions the spread of entanglement in these models is highly sensitive to the initial entanglement pattern, but we are able to prove an upper bound on the normalized rate of growth of entanglement entropy, and hence the tsunami velocity. The bound is smaller than what one gets for quenches in holographic theories, which highlights the importance of interactions in the spread of entanglement in many-body systems. We propose an interacting model which we believe provides an upper bound on the spread of entanglement for interacting relativistic theories. In two spacetime dimensions with multi...

  19. 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.

  20. 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

  1. 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.

  2. Influência do tratamento químico da fibra de bananeira em compósitos de poli(etileno-co-acetato de vinila com e sem agente de expansão

    Directory of Open Access Journals (Sweden)

    Matheus V. G. Zimmermann

    2014-01-01

    Full Text Available Neste trabalho foi avaliada a influência do tratamento alcalino na fibra de bananeira (FB e seu uso como agente de reforço em compósitos expandidos de poli(etileno-co-acetato de vinila - EVA. O processo de mistura dos compósitos ocorreu em um misturador de rolos aberto e após conformados e expandidos em uma prensa aquecida com moldes de volumes variáveis. Os compósitos foram avaliados por suas propriedades mecânicas, térmicas e morfológicas. Os resultados indicam que o tratamento alcalino promove a extração de componentes menos estáveis na FB, tais como a lignina, hemicelulose, ceras e óleos de baixo peso molecular. O uso da FB nos compósitos proporciona um decréscimo das propriedades mecânicas de resistência à tração e rasgo em relação ao EVA puro devido a moderadas propriedades de interface polímero-fibra. Nos compósitos expandidos, as propriedades mecânicas decrescem com a diminuição da densidade em função da maior presença de espaços vazios no interior dos compósitos, porém as propriedades mecânicas específicas de resistência ao rasgo apresentaram melhores resultados com 10 pcr de FB em todos os moldes utilizados.

  3. Perception of causality in schizophrenia spectrum disorder.

    Science.gov (United States)

    Tschacher, Wolfgang; Kupper, Zeno

    2006-10-01

    Patients with schizophrenia spectrum disorders often maintain deviating views on cause-effect relationships, especially when positive and disorganization symptoms are manifest. Altered perceived causality is prominent in delusional ideation, in ideas of reference, and in the mentalizing ability (theory of mind [ToM]) of patients. Perceiving causal relationships may be understood either as higher order cognitive reasoning or as low-level information processing. In the present study, perception of causality was investigated as a low-level, preattentional capability similar to gestalt-like perceptual organization. Thirty-one patients (24 men and 7 women with mean age 27.7 years) and the same number of healthy control subjects matched to patients with respect to age and sex were tested. A visual paradigm was used in which 2 identical discs move, from opposite sides of a monitor, steadily toward and then past one another. Their coincidence generates an ambiguous, bistable percept (discs either "stream through" or "bounce off" one another). The bouncing perception, ie, perceived causality, is enhanced when auditory stimuli are presented at the time of coincidence. Psychopathology was measured using the Positive and Negative Syndrome Scale. It was found that positive symptoms were strongly associated with increased perceived causality and disorganization with attenuated perceived causality. Patients in general were not significantly different from controls, but symptom subgroups showed specifically altered perceived causality. Perceived causality as a basic preattentional process may contribute to higher order cognitive alterations and ToM deficiencies. It is suggested that cognitive remediation therapy should address both increased and reduced perception of causality. PMID:16896057

  4. Alignment in the decision-making process between agents in biodiesel supply chains; Identificacao dos fatores e motivacoes relacionados ao processo de tomada de decisao dos diferentes agentes da cadeia produtiva do biodiesel do Rio Grande do Sul, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Rathmann, Regis; Santos, Omar Inacio Benedetti [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE). Programa de Planejamento Energetico; Padula, Antonio Domingos [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)

    2008-07-01

    The aim of the present study is to identify and analyze the factors, motivations and criteria being considered in the decision-making processes of the actors belonging to the biodiesel production chain in RS, and confirm or otherwise, the existence of alignment in the decision-making process. Interviews were carried out with the main agents of the links that comprise the biodiesel chains in RS: 11 agricultural co-operatives, 3 biodiesel production plants and a firm that processes and distributes diesel/biodiesel. With regard the decision-making process of the cooperatives, it is centered on the decision to offer, or otherwise, oil-bearing crops for the production of biodiesel. Their decisions emphasize operational and short-term aspects. In contrast, in the firms producing biodiesel, their decision to produce this fuel is associated with addition of one more product to their market portfolio, and is correlated with a long-term view and the search for economic efficiency. In these firms, the benefits of the tax incentives offered by the public policies strongly influence the decision regarding the alternative oil-bearing crops used in the production of biodiesel. In the distributor, it was seen that the decision-making process was guided by long-term strategies. The decision to mix biodiesel with diesel oil being related to the institutional aspect, whatever the legal obligation to mix the fuels may be. In summary, the results show the existence of different characteristics linked to the decision-making process and a significant lack of synchronicity in the aims and motivations of the agents decisions. This state of decisional mis-alignment, associated with the fragilities of public policy, leads to heightened uncertainty regarding the sustainability of the Brazilian biodiesel production program. (author)

  5. Nanocompósitos de polietileno/argila bentonita nacional: influência da argila e do agente compatibilizante PE-g-MA nas propriedades mecânicas e de inflamabilidade Polyethylene/national bentonite clay nanocomposites: influence of clay and PE-g-MA coupling agent on the mechanical properties and flammability

    Directory of Open Access Journals (Sweden)

    Gustavo F. Brito

    2008-06-01

    Full Text Available Nanocompósitos de polietileno de alta densidade/argila bentonita nacional foram preparados por intercalação por fusão. A influência da adição da argila sem tratamento e da argila tratada com o sal quaternário de amônio Cetremide e do polietileno graftizado com anidrido maléico (PE-g-MA como agente compatibilizante foi avaliada. Os sistemas obtidos foram caracterizados por inflamabilidade, propriedades mecânicas e reológicas, difração de raios X e microscopia eletrônica de transmissão. Os resultados de difração de raios X e microscopia eletrônica de transmissão indicaram a obtenção de nanocompósitos com estruturas parcialmente esfoliadas e/ou intercaladas que conduziram ao aumento do módulo de elasticidade e do valor do torque. O teste de inflamabilidade mostrou que a adição da argila na matriz polimérica e a presença do PE-g-MA retardaram a velocidade de queima do sistema, ou seja, diminuíram a inflamabilidade do PE puro. Em geral, o sistema contendo o agente compatibilizante (PE-g-MA exibiu melhorias na estabilidade térmica e nanocompósitos parcialmente esfoliados foram formados, quando comparados à matriz de polietileno de alta densidade. O polietileno graftizado com anidrido maléico não apenas promoveu a esfoliação da argila, mas também facilitou a adesão carga-matriz, obtendo-se com isso melhorias nos resultados mecânicos do sistema.High density polyethylene/national bentonite clay nanocomposites were prepared with the melt intercalation technique. The effect of the clay without treatment and clay treated with quaternary ammonium salt Cetremide with polyethylene-graft-maleic anhydride as coupling agent was evaluated. The systems were characterized by flammability, mechanical and rheological properties, X ray diffraction and transmission electron microscopy. In general, the results of X ray diffraction and transmission electron microscopy showed partially exfoliated and/or intercalated structures with

  6. On the origin of Hill's causal criteria.

    Science.gov (United States)

    Morabia, A

    1991-09-01

    The rules to assess causation formulated by the eighteenth century Scottish philosopher David Hume are compared to Sir Austin Bradford Hill's causal criteria. The strength of the analogy between Hume's rules and Hill's causal criteria suggests that, irrespective of whether Hume's work was known to Hill or Hill's predecessors, Hume's thinking expresses a point of view still widely shared by contemporary epidemiologists. The lack of systematic experimental proof to causal inferences in epidemiology may explain the analogy of Hume's and Hill's, as opposed to Popper's, logic.

  7. Causal localizations in relativistic quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Leiseifer, Andreas David

    2014-06-30

    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. 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.

  9. Causal structures of pp-waves

    CERN Document Server

    Hubeny, V E; Hubeny, Veronika E.; Rangamani, Mukund

    2002-01-01

    We discuss the causal structure of pp-wave spacetimes using the ideal point construction outlined by Geroch, Kronheimer, and Penrose. This generalizes the recent work of Marolf and Ross, who considered similar issues for plane wave spacetimes. We address the question regarding the dimension of the causal boundary for certain specific pp-wave backgrounds. In particular, we demonstrate that the pp-wave spacetime which gives rise to the N = 2 sine-Gordon string world-sheet theory is geodesically complete and has a one-dimensional causal boundary.

  10. 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.

  11. Intrinsic Universality of Causal Graph Dynamics

    Directory of Open Access Journals (Sweden)

    Simon Martiel

    2013-09-01

    Full Text Available Causal graph dynamics are transformations over graphs that capture two important symmetries of physics, namely causality and homogeneity. They can be equivalently defined as continuous and translation invariant transformations or functions induced by a local rule applied simultaneously on every vertex of the graph. Intrinsic universality is the ability of an instance of a model to simulate every other instance of the model while preserving the structure of the computation at every step of the simulation. In this work we present the construction of a family of intrinsically universal instances of causal graphs dynamics, each instance being able to simulate a subset of instances.

  12. Blendas de poliamida 6/elastômero: propriedades e influência da adição de agente compatibilizante

    OpenAIRE

    Barra Guilherme M. O.; Roeder Jerusa; Soldi Valdir; Pires Alfredo T. N.; Agnelli José A. M.

    2003-01-01

    Neste trabalho foram estudadas as propriedades micro e macroscópicas de misturas físicas binárias de poliamida 6 [PA6] com copolímero poli(etileno-co-propileno-co-dieno) [EPDM] e em presença de pequenas quantidades de EPDM ou EPM enxertados com anidrido maleico, atuando como agentes compatibilizantes. Os componentes puros (poliamida 6 e EPDM) e as blendas poliméricas em diferentes composições foram analisados por calorimetria diferencial de varredura (DSC) e espectroscopia de infravermelho (F...

  13. Synthesis and preliminary evaluation of N-acylhydrazone compounds as antibacterial and antifungal agents; Sintese e avaliacao preliminar da atividade antibacteriana e antifungica de derivados N-acilidrazonicos

    Energy Technology Data Exchange (ETDEWEB)

    Cachiba, Thomas Haruo; Carvalho, Bruno Demartini; Carvalho, Diogo Teixeira [Universidade Federal de Alfenas, MG (Brazil). Fac. de Ciencias Farmaceuticas. Dept. de Alimentos e Medicamentos; Cusinato, Marina; Prado, Clara Gaviao; Dias, Amanda Latercia Tranches, E-mail: diogo.carvalho@unifal-mg.edu.br [Universidade Federal de Alfenas, MG (Brazil). Inst. de Ciencias Biomedicas

    2012-07-01

    We describe the synthesis and evaluation of N-acylhydrazone compounds bearing different electron-donating groups in one of its aromatic rings, obtained using a four-step synthetic route. IC{sub 50} values against pathogenic fungi and bacteria were determined by serial microdilution. Compounds showed low activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. By contrast, a derivative with a meta-oriented electron-donating group showed significant activity (IC50) against Candida albicans (17 {mu}M), C. krusei (34 {mu}M) and C. tropicalis (17 {mu}M). Results suggest this is a promising lead-compound for synthesis of potent antifungal agents. (author)

  14. Avaliação clínica e morfológica da ação da hidroquinona e do ácido fítico como agentes despigmentantes

    OpenAIRE

    Gardoni, Benilda L. K.; Sato, Mayumi Eliza Otsuka; Pontarolo, Roberto; Noronha, Lucía; Reichert, Adriane; Serafini, Sergio Z.

    2004-01-01

    A eficácia in vivo do creme de ácido fítico 2% (A), foi comparada ao de hidroquinona 4% (B), em estudo comparativo duplo cego, com dezoito voluntários sadios, pele fototipo IV (Fitzpatrick). Na análise macroscópica não se observou alterações na coloração da pele. No ensaio histoquímico subjetivo não houve redução perceptível do pigmento melânico. Observou-se significativa redução do número de melanócitos com a hidroquinona (28,22), superior ao ácido fítico (30,74) e ao controle (3...

  15. Domain-specific perceptual causality in children depends on the spatio-temporal configuration, not motion onset

    Directory of Open Access Journals (Sweden)

    Anne eSchlottmann

    2013-07-01

    Full Text Available Humans, even babies, perceive causality when one shape moves briefly and linearly after another. Motion timing is crucial in this and causal impressions disappear with short delays between motions. However, the role of temporal information is more complex: It is both a cue to causality and a factor that constrains processing. It affects ability to distinguish causality from non-causality, and social from mechanical causality. Here we study both issues with 3- to 7-year-olds and adults who saw two computer-animated squares and chose if a picture of mechanical, social or non-causality fit each event best. Prior work fit with the standard view that early in development, the distinction between the social and physical domains depends mainly on whether or not the agents make contact, and that this reflects concern with domain-specific motion onset, in particular, whether the motion is self-initiated or not. The present experiments challenge both parts of this position. In Experiments 1 and 2, we showed that not just spatial, but also animacy and temporal information affect how children distinguish between physical and social causality. In Experiments 3 and 4 we showed that children do not seem to use spatio-temporal information in perceptual causality to make inferences about self- or other-initiated motion onset. Overall, spatial contact may be developmentally primary in domain-specific perceptual causality in that it is processed easily and is dominant over competing cues, but it is not the only cue used early on and it is not used to infer motion onset. Instead, domain-specific causal impressions may be automatic reactions to specific perceptual configurations, with a complex role for temporal information.

  16. 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...

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  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. 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.

  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. Locally Causal Dynamical Triangulations in Two Dimensions

    CERN Document Server

    Loll, Renate

    2015-01-01

    We analyze the universal properties of a new two-dimensional quantum gravity model defined in terms of Locally Causal Dynamical Triangulations (LCDT). Measuring the Hausdorff and spectral dimensions of the dynamical geometrical ensemble, we find numerical evidence that the continuum limit of the model lies in a new universality class of two-dimensional quantum gravity theories, inequivalent to both Euclidean and Causal Dynamical Triangulations.

  6. 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.

  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. 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.

  10. Evaluation of the in vitro activity of six antimicrobial agents against Neisseria gonorrhoeae Avaliação in vitro da atividade de seis drogas antimicrobianas contra Neisseria gonorrhoeae

    Directory of Open Access Journals (Sweden)

    Walter Belda Junior

    2007-02-01

    Full Text Available Use of antimicrobials for the treatment of gonorrhea started in 1930 with the utilization of sulfonamides. With the years other drugs were used for its treatment such as penicillin, tetracycline, spectinomycin, and others. Although highly specific in the beginning, these drugs, with time did not show anymore the expected therapeutic results because of aspects of chromosomal and plasmid-mediated resistance. The purpose of this study was to evaluate the susceptibility of Neisseria gonorrhoeae strains to six drugs used for its treatment (penicillin, tetracycline, cefoxitin, thiamphenicol, spectinomycin and ofloxacin by the determination of minimal inhibitory concentrations of these drugs. We concluded that drugs, such as cefoxitin, thiamphenicol and spectinomycin still are excellent pharmacological agents for the treatment of gonorrhea. Penicillin, although still efficient, needs more attention regarding its use, as well as ofloxacin, because of the emergence of resistant strains. Tetracycline and its derivatives should be strongly contraindicated for the treatment of gonorrhea.A utilização de antimicrobianos no tratamento da gonorréia iniciou-se em 1930 com a utilização das sulfonamidas. No decorrer dos anos outras drogas passaram a ser utilizadas em seu tratamento como a penicilina, tetraciclina, espectinomicina e outras. Embora altamente eficazes no início, essas drogas, ao longo do tempo, passaram a não mais apresentar o resultado terapêutico esperado em virtude do aparecimento de quadros de resistência cromossômica e plasmidial. Este trabalho teve por objetivo avaliar a sensibilidade de cepas de Neisseria gonorrhoeae a seis drogas utilizadas no seu tratamento (penicilina, tetraciclina, cefoxitina, tianfenicol, espectinomicina e ofloxacina através da concentração inibitória mínima. Concluimos que drogas como a cefoxitina, o tianfenicol e a espectinomicina ainda constituem excelentes fármacos para o tratamento da gonorréia. A

  11. 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

  12. DIREITOS DOS USUÁRIOS DA SAÚDE: ESTRATÉGIAS PARA EMPODERAR AGENTES COMUNITÁRIOS DE SAÚDE E COMUNIDADE

    Directory of Open Access Journals (Sweden)

    Gabriela Marcellino de Melo Lanzoni

    2009-01-01

    Full Text Available Investigación Convergente Asistencial bajo el punto de vista teórico de Paulo Freire, cuyo objetivo fue desvelar críticamente la Carta de los Derechos de los Usuarios de la Salud y crear estrategias de poderío de la comunidad mediante la realización de talleres educativos. Participaron 470 Agentes Comunitarios de Salud de Florianópolis/SC, organizados en pequeños grupos de dialogo, que elaboraron cinco estrategias para lograr el cumplimiento de los derechos y obligaciones de los usuarios, a saber: divulgar la importancia del Consejo Local de Salud en las visitas a domicilio; El plan de orientación a los usuarios acerca de los medicamentos; Fijar carteles en la Unidad Local de Salud sobre el primer principio de la Carta; Divulgar otros servicios de apoyo a la salud; y, Divulgación y poderío de la comunidad sobre sus derechos y deberes. Las intervenciones señaladas inspiran el fortalecimiento de las acciones en educación y salud, con miras a la instrumentalización del equipo de salud, sin exigir del Estado demandas en la estructura socio-económica.

  13. Linear structures, causal sets and topology

    Science.gov (United States)

    Hudetz, Laurenz

    2015-11-01

    Causal set theory and the theory of linear structures (which has recently been developed by Tim Maudlin as an alternative to standard topology) share some of their main motivations. In view of that, I raise and answer the question how these two theories are related to each other and to standard topology. I show that causal set theory can be embedded into Maudlin's more general framework and I characterise what Maudlin's topological concepts boil down to when applied to discrete linear structures that correspond to causal sets. Moreover, I show that all topological aspects of causal sets that can be described in Maudlin's theory can also be described in the framework of standard topology. Finally, I discuss why these results are relevant for evaluating Maudlin's theory. The value of this theory depends crucially on whether it is true that (a) its conceptual framework is as expressive as that of standard topology when it comes to describing well-known continuous as well as discrete models of spacetime and (b) it is even more expressive or fruitful when it comes to analysing topological aspects of discrete structures that are intended as models of spacetime. On one hand, my theorems support (a). The theory is rich enough to incorporate causal set theory and its definitions of topological notions yield a plausible outcome in the case of causal sets. On the other hand, the results undermine (b). Standard topology, too, has the conceptual resources to capture those topological aspects of causal sets that are analysable within Maudlin's framework. This fact poses a challenge for the proponents of Maudlin's theory to prove it fruitful.

  14. The Cradle of Causal Reasoning: Newborns' Preference for Physical Causality

    Science.gov (United States)

    Mascalzoni, Elena; Regolin, Lucia; Vallortigara, Giorgio; Simion, Francesca

    2013-01-01

    Perception of mechanical (i.e. physical) causality, in terms of a cause-effect relationship between two motion events, appears to be a powerful mechanism in our daily experience. In spite of a growing interest in the earliest causal representations, the role of experience in the origin of this sensitivity is still a matter of dispute. Here, we…

  15. Efetividade de programa de agentes comunitários na promoção da saúde bucal Efectividad del programa de agentes comunitarios en la promoción de la salud bucal Effectiveness of a community health worker program on oral health promotion

    Directory of Open Access Journals (Sweden)

    Paulo Frazão

    2009-06-01

    Full Text Available OBJETIVO:Avaliar mudanças em conhecimentos, atitudes e acesso/utilização de serviços odontológicos decorrentes de um programa de promoção da saúde bucal com agentes comunitários de saúde. MÉTODOS:Um projeto de capacitação combinando ensino-aprendizagem, apoio e supervisão, foi desenvolvido entre os meses de julho de 2003 a agosto de 2004. As mudanças foram avaliadas por meio de entrevistas estruturadas em que participaram 36 agentes comunitários de saúde e uma amostra de 91 mulheres e mães, representativa de donas de casa com 25 a 39 anos de idade, alfabetizadas e residentes em domicílios de três a seis cômodos no município de Rio Grande da Serra (SP. Foram colhidos dados sobre conhecimentos de saúde-doença bucal, práticas e capacidades auto-referidas em relação ao auto-exame, higiene bucal, número de residentes e de escovas dentais individuais e coletivas em cada domicílio e acesso e uso de serviços odontológicos. Por meio do teste t de Student pareado, foram comparadas as médias dos valores obtidos antes e depois do programa para cada um dos grupos estudados. As respostas foram analisadas adotando-se um nível de significância de 5%. RESULTADOS: Foram observadas diferenças estatisticamente significativas para questões relativas ao conhecimento de saúde bucal entre os agentes e entre as mulheres antes e depois da capacitação (pOBJETIVO: Evaluar cambios en conocimientos, actitudes y acceso/utilización de servicios odontológicos productos de un programa de promoción de la salud bucal con agentes comunitarios de salud. MÉTODOS: Un proyecto de capacitación combinando enseñanza-aprendizaje, apoyo y supervisión, fue desarrollado entre los meses de julio de 2003 a agosto de 2004. Los cambios fueron evaluados por medio de entrevistas estructuradas en las que participaron 36 agentes comunitarios de salud y una muestra representativa de 91 mujeres y madres amas de casa con 25 a 39 años de edad, alfabetizadas

  16. Comparative study of the action of two different types of bleaching agents activated by two different types of irradiation fonts: xenon plasma arc lamp and 960 nm diode laser; Avaliacao da cor e estudo comparativo da acao de dois tipos diferentes de agentes clareadores ativados pelo laser de diodo e lampada xenonio plasmatica, na superficie do esmalte

    Energy Technology Data Exchange (ETDEWEB)

    Walverde, Debora Ayala

    2001-07-01

    This in vitro study compares two different types of tooth bleaching agents stimulated with two different irradiation fonts. These fonts accelerate the action of the bleaching agents upon the enamel surface by heating up the materials. We used the xenon plasma arc lamp and a 960 nm fiber-coupled diode laser to irradiate the two materials containing 35% of hydrogen peroxide (Opus White and Opalescence extra). The color of the teeth was measured with a spectrophotometer using the CIELAB color system that gives the numeric values of L{sup *}a{sup *}b{sup *}. (author)

  17. Causal impressions: predicting when, not just whether.

    Science.gov (United States)

    Young, Michael E; Rogers, Ester T; Beckmann, Joshua S

    2005-03-01

    In 1739, David Hume established the so-called cues to causality--environmental cues that are important to the inference of causality. Although this descriptive account has been corroborated experimentally, it has not been established why these cues are useful, except that they may reflect statistical regularities in the environment. One of the cues to causality, covariation, helps predict whether an effect will occur, but not its time of occurrence. In the present study, evidence is provided that spatial and temporal contiguity improve an observer's ability to predict when an effect will occur, thus complementing the utility of covariation as a predictor of whether an effect will occur. While observing Michotte's (1946/1963) launching effect, participants showed greater accuracy and precision in their predictions of the onset of movement by the launched object when there was spatial and temporal contiguity. Furthermore, when auditory cues that bridged a delayed launch were included, causal ratings and predictability were similarly affected. These results suggest that the everyday inference of causality relies on our ability to predict whether and when an effect will occur.

  18. 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.

  19. Doença da arranhadura do gato por Bartonella quintana em lactente: uma apresentação incomum

    Directory of Open Access Journals (Sweden)

    Azevedo Zina Maria Almeida de

    2000-01-01

    Full Text Available Relato de caso de doença da arranhadura do gato (DAG, em um paciente lactente, com história epidemiológica negativa, descrevendo o rastreamento diagnóstico, a imagem ao ultra-som, a evolução clínica e o prognóstico. B. quintana foi identificada em aspirado de secreção ganglionar pelo método de PCR. B. henselae, embora seja o agente causal habitualmente responsável pela DAG, não foi isolada. Os autores concluem que a pesquisa de B. quintana e B. henselae deve ser incluída na investigação de adenites, principalmente quando a evolução é subaguda, mesmo em lactentes e, ainda que a história epidemiológica seja negativa.

  20. Causal binding of actions to their effects.

    Science.gov (United States)

    Buehner, Marc J; Humphreys, Gruffydd R

    2009-10-01

    According to widely held views in cognitive science harking back to David Hume, causality cannot be perceived directly, but instead is inferred from patterns of sensory experience, and the quality of these inferences is determined by perceivable quantities such as contingency and contiguity. We report results that suggest a reversal of Hume's conjecture: People's sense of time is warped by the experience of causality. In a stimulus-anticipation task, participants' response behavior reflected a shortened experience of time in the case of target stimuli participants themselves had generated, relative to equidistant, equally predictable stimuli they had not caused. These findings suggest that causality in the mind leads to temporal binding of cause and effect, and extend and generalize beyond earlier claims of intentional binding between action and outcome.

  1. 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.

  2. 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

  3. 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...

  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. 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.

  6. 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....

  7. Inferring causality from noisy time series data

    DEFF Research Database (Denmark)

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

    2016-01-01

    Convergent Cross-Mapping (CCM) has shown high potential to perform causal inference in the absence of models. We assess the strengths and weaknesses of the method by varying coupling strength and noise levels in coupled logistic maps. We find that CCM fails to infer accurate coupling strength...... injections in intermediate-to-strongly coupled systems could enable more accurate causal inferences. Given the inherent noisy nature of real-world systems, our findings enable a more accurate evaluation of CCM applicability and advance suggestions on how to overcome its weaknesses....

  8. Proposta de uma Arquitetura de Agentes Móveis para Recuperação de Informação Útil e Distribuída no Processo de Gestão do Conhecimento

    Directory of Open Access Journals (Sweden)

    Andréa Sabedra Bordin

    2005-06-01

    Full Text Available O processo de gestão do conhecimento no contexto institucional caracteriza-se pela gestão da competência dos seus colaboradores, seus relacionamentos internos e externos. Nesse sentido, abordagens e técnicas computacionais que capturem informações sobre as competências do colaborador de maneira explícita e tácita fazem-se necessárias. A abordagem utilizada neste artigo considera que na maioria das situações o colaborador explicita suas competências na forma de um curriculum vitae, o qual contém informações sobre sua formação escolar, experiência de trabalho, suas aptidões, etc. e o armazena dentro do seu computador pessoal no formato textual. Diante disso, propõe-se a utilização de uma arquitetura de agentes móveis que realize a detecção dessas informações na intranet institucional para formação de uma base textual única e centralizada que será utilizada no processo de gestão do conhecimento.

  9. Tolerância a agente curarizante provocada pela administração repetida da droga Tolerance to curarizing drug induced by chronic administration: an experimental study

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Zanini

    1974-03-01

    Full Text Available Baseados em teoria discutível segundo a qual a miastenia grave é provocada pela presença no sangue de substância curarizante liberada pelo timo, tentou-se reproduzir um modelo experimental. Foram utilizados 40 ratos, criados nas mesmas condições, nascidos no mesmo dia, pesando ao redor de 350 g e divididos em 4 grupos: o Grupo I não foi manuseado; no Grupo II foi injetada solução fisiológica, 1 ml i.p. durante 6 semanas; no Grupo III foi injetada a dimetil tubocurarina (DMT 2,8 mcg/kg i.p., durante o mesmo tempo; no Grupo IV 14 mcg/kg da mesma droga foram injetados i.p. Uma semana após a última injeção i.p. os ratos, anestesiados, foram preparados para registro neuromuscular. O nervo ciático foi estimulado nas freqüências de 0,33 pulsos/seg, 70 pulsos/seg (séries de 10 pulsos a intervalos de 3 seg, 70 pulsos/seg (mantidos por 15 seg e novamente 0,33 pulsos/seg logo após a tetanização. A dose curarizante de DMT foi determinada por uma "terceira parte cega" quando 80% do bloqueio era alcançado. Quando apenas 10 estímulos em alta freqüência foram aplicados ao nervo, foi observada diferença significativa (pThe trial is a temptative experimental model of myasthenia gravis based on a doubtful theory whereby this disease is atributed to circulating curare in blood. Forty rats kept under the same conditions, bom on the same day and weighing around 350 g entered the trial, divided in four groups. Group I was not handled, Group II was injected with saline, 1 ml i.p. Group III was submitted to dimethyl tubocurarine iodide (DMT 2,8 mcg/kg i.p. and Group IV received 14 mcg/kg, all solutions being administered daily for a six-week period. One week after the last rats were anesthetized and prepared for cyatic-gastrocnemius neuro-muscular recording. Monopolar pulses were given at frequencies of 0.33 p/sec, 70 p/sec, (trains of 10 pulses at 3 sec intervals, 70 p/sec (kept for 15 sec and again 0.33 p/sec right after tetanus. Curarizing

  10. Equivalência de dulçor e poder edulcorante de edulcorantes em função da temperatura de consumo em bebidas preparadas com chá-mate em pó solúvel Equi-sweetness and sweetening power of different sweetening agents in differents temperatures of consumption of tea drink in soluble power

    OpenAIRE

    Juliana Maria Porto Cardoso; Juliana Rosa Battochio; Helena Maria André Bolini Cardello

    2004-01-01

    No presente estudo foi verificado o efeito da temperatura de consumo na equivalência de doçura e no poder edulcorante de diferentes agentes adoçantes em bebida de chá-mate em pó solúvel. Foram avaliados: aspartame, sucralose, mistura ciclamato/sacarina 2:1, Stevia e acessulfame-K, tendo como referência a sacarose. Todos os estudos foram realizados a 6±2ºC e a 45±2ºC. Primeiramente foi determinada a doçura ideal, utillizando-se escala do ideal com 30 provadores consumidores da be...

  11. O papel dos antipsicóticos atípicos no tratamento do transtorno bipolar: revisão da literatura The role of atypical antipsychotic agents in the treatment of bipolar disorder: a literature review

    Directory of Open Access Journals (Sweden)

    Acioly LT Lacerda

    2002-03-01

    Full Text Available Estudos recentes têm demonstrado que a eficácia do lítio é significativamente inferior à descrita pelos primeiros trabalhos, embora ainda seja a medicação de referência no tratamento do transtorno afetivo bipolar. Apesar de um perfil de segurança desfavorável, os antipsicóticos clássicos sempre apresentaram um papel importante no tratamento desse transtorno psiquiátrico, especialmente como coadjuvante em sua fase maníaca aguda. Os autores, utilizando informação obtida no Medline, fizeram uma revisão acerca do papel dos antipsicóticos atípicos no tratamento dos pacientes bipolares. Baseado nos dados da literatura, a olanzapina mostrou-se bastante eficaz no manejo da mania aguda, quando uma média de 63,5% dos pacientes apresentaram melhora significativa em estudos duplo-cego controlados, apresentando ganho de peso como único efeito colateral relevante. A clozapina e, mais ainda, a risperidona apresentaram dados menos consistentes, grande parte em função de deficiências metodológicas dos poucos estudos conduzidos até o presente estudo. Os dados preliminares relativos à eficácia desse grupo farmacológico nos quadros refratários e nos sintomas depressivos são promissores, mas ainda não definitivos. Em relação a seus efeitos potenciais como estabilizadores do humor, não existem evidências conclusivas oriundas de estudos controlados, mas há interesse considerável para realização de investigações em pacientes bipolares tratados com antipsicóticos atípicos por períodos de tempo mais prolongados. Pesquisas futuras poderão tornar mais claras essas possíveis características terapêuticas.Even though lithium is still the choice drug in the treatment of bipolar disorder, recent studies have shown that it has a significant lower efficacy than previously described in earlier studies. Despite its adverse side effects, typical antipsychotic agents have often had a prominent role in the treatment of this psychiatric

  12. Agentes comunitários de saúde da zona leste do município de São Paulo: um olhar para seu estado nutricional e consumo alimentar - doi:10.5020/18061230.2008.p3

    Directory of Open Access Journals (Sweden)

    Alexanndra Corrêa de Freitas

    2012-01-01

    Full Text Available Objetivo: Caracterizar o perfil sócio-demográfico, o estado nutricional, a presença de doenças crônicas não-transmissíveis e o consumo alimentar de agentes comunitários de saúde (ACS pertencentes a cinco Unidades de Saúde da Família da Zona Leste do Município de São Paulo. Métodos: Tratou-se de um estudo quantitativo, descritivo e exploratório desenvolvido com 88 indivíduos. Coletaram-se dados sobre a situação sócio-demográfica, dados antropométricos(peso, estatura e circunferência da cintura, informações sobre presença de doenças crônicas não-transmissíveis e de consumo alimentar. Resultados: Os participantes dessa pesquisa eram predominantemente do sexo feminino 83 (94,3%, com idade variável entre 20 e 55 anos. A maioria era natural da região Sudeste 72 (81,2%, possuía ensino médio concluído 71 (80,7% e tinha renda familiar entre 2 e 5 salários mínimos 62 (70,4%. A avaliação antropométrica revelou que 46 (52,3% estavam eutróficos, 41 (46,6% com excesso de peso e 41 (46,6% apresentavam risco elevado ou muito elevado para doenças cardiovasculares, apesar de 77 (87,5% não terem referido qualquer doença crônica não-transmissível. Quanto ao consumo alimentar, encontrou-se consumo diário de arroz, feijão, pão e margarina ou manteiga e baixo consumo de leite e derivados, frutas, verduras e legumes. As carnes bovina e de frango eram as mais consumidas. O café apareceu como bebida de maior consumo diário, seguido do suco artificial. As frituras e doces eram consumidos semanalmente por 34,9% e 53,4% dos ACS, respectivamente. Conclusão: O excesso de peso e a obesidade abdominal foram os principais acometimentos à saúde dos ACS, tendo, ambos, estreita relação com suas práticas alimentares inadequadas; as quais também estavam relacionadas às suas características sócio-demográficas. NCT00682604.

  13. Introducing Mechanics by Tapping Core Causal Knowledge

    Science.gov (United States)

    Klaassen, Kees; Westra, Axel; Emmett, Katrina; Eijkelhof, Harrie; Lijnse, Piet

    2008-01-01

    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…

  14. 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…

  15. 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.

  16. The metagenomic approach and causality in virology

    Directory of Open Access Journals (Sweden)

    Silvana Beres Castrignano

    2015-01-01

    Full Text Available Nowadays, the metagenomic approach has been a very important tool in the discovery of new viruses in environmental and biological samples. Here we discuss how these discoveries may help to elucidate the etiology of diseases and the criteria necessary to establish a causal association between a virus and a disease.

  17. Causality and Time in Historical Institutionalism

    DEFF Research Database (Denmark)

    Mahoney, James; Mohamedali, Khairunnisa; Nguyen, Christoph

    2016-01-01

    This chapter explores the dual concern with causality and time in historical institutionalism using a graphical approach. The analysis focuses on three concepts that are central to this field: critical junctures, gradual change, and path dependence. The analysis makes explicit and formal the logic...

  18. 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…

  19. Exploring Torus Universes in Causal Dynamical Triangulations

    DEFF Research Database (Denmark)

    Budd, Timothy George; Loll, R.

    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...

  20. Marriage and Anomie: A Causal Argument

    Science.gov (United States)

    Lee, Gary R.

    1974-01-01

    A sample of 394 married couples is employed to test the possibility of an association between marital satisfaction and personal (attitudinal) anomie. The hypothesis is supported. Conclusions are offered relevant to anomie theory, and to utilization of marital and family phenomena as independent variables in causal explanations of nonfamily events.…

  1. 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.

  2. 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…

  3. 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…

  4. 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.)

  5. 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…

  6. Sequential causal learning in humans and rats

    NARCIS (Netherlands)

    H. Lu; R.R. Rojas; T. Beckers; A. Yuille

    2008-01-01

    Recent experiments (Beckers, De Houwer, Pineño, & Miller, 2005;Beckers, Miller, De Houwer, & Urushihara, 2006) have shown that pretraining with unrelated cues can dramatically influence the performance of humans in a causal learning paradigm and rats in a standard Pavlovian conditioning paradigm. Su

  7. Fate of Clavibacter michiganensis ssp. sepedonicus, the causal organism of bacterial ring rot in potato, in weeds and field crops.

    NARCIS (Netherlands)

    Wolf, van der J.M.; Beckhoven, van J.R.C.M.; Hukkanen, A.; Karjalainen, R.; Muller, P.

    2005-01-01

    Crops and weeds were tested for their ability to host Clavibacter michiganensis ssp. sepedonicus (Cms), the causal agent of bacterial ring rot in potato. Ten crops grown in rotation with potato in Europe, namely maize, wheat, barley, oat, bush bean, broad bean, rape, pea and onion and five cultivars

  8. Avaliação do método de disco-difusão para determinação da eficácia da terbinafina in vitro em agentes de micoses superficiais e subcutâneas Evaluation of the disk-diffusion method to determine the in vitro efficacy of terbinafine against subcutaneous and superficial mycoses agents

    OpenAIRE

    Hilda Conceição Diogo; Márcia Melhem; Aldo Sarpieri; Mario Cezar Pires

    2010-01-01

    FUNDAMENTOS: As micoses superficiais e subcutâneas têm alta prevalência e, muitas vezes, caráter crônico, necessitando tratamentos tópicos e/ou sistêmicos com antifúngicos. As drogas de escolha são azóis e alilaminas (terbinafina). É necessário avaliar a eficácia das drogas para tratamento em humanos e em animais. Estudos para avaliar in vitro a ação dos antimicóticos são raros, especialmente, contra fungos filamentosos. OBJETIVO: Avaliar a eficácia in vitro da terbinafina pelo método de disc...

  9. 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

  10. Cirurgia conservadora da endocardite bacteriana aguda da valva tricúspide Conservative operation for bacterial endocardites of the tricuspide valve

    Directory of Open Access Journals (Sweden)

    Iseu Affonso da Costa

    1988-08-01

    Full Text Available É relatado o caso de 1 paciente que apresentou endocardite aguda da valva tricúspide pós-aborto, cujo agente causal era o S. aureus. Como não houvesse resposta favorável ao tratamento antibiótico (gentamicina, vancomicina e oxacilina, optou-se pela intervenção, vinte dias após a internação. Foi praticada excisão de uma vegetação única e do tecido valvar adjacente, na comissura ântero-posterior e plicatura anular. O resultado foi favorável, com cura clínica. O exame ecocardiográfico confirmou a presença da vegetação no pré-operatório e o funcionamento conservado da valva, após a plastia. O tratamento cirúrgico, com retirada do tecido infectado e preservação da valva constitui uma alternativa aplicável a certos casos de endocardite aguda das valvas atrioventriculares.One case of acute bacterial endocarditis of the tricuspid valve caused by S. aureus and following a septic abortion is presented. Surgical treatment was indicated after failure of antibiotics. Operation consisted of excision of a large vegetation adherent to the anterior and posterior cusps at the commisure and of the affected valvar tissue. Annular plicature at the segment corresponding to the posterior cuspid was employed to maintain competence. Clinical result was very satisfactory with resolution of sepsis. Dopplerecocardiography revealed the presence of the vegetation before the operation and showed a small regurgitation after valvoplasty. Conservative operation upon the atrioventricular valves must be kept in mind as an alternative in the treatment of acute bacterial endocarditis.

  11. 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...

  12. 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...

  13. Antibiotic Agents

    Science.gov (United States)

    ... either as public health or as non-public health antimicrobial agents. What is the difference between bacteriostats, sanitizers, disinfectants ... bacteria, however, there is considerable controversy surrounding their health benefits. The ... producing agents (Table of Antibacterials) have been used for many ...

  14. Interpretational Confounding or Confounded Interpretations of Causal Indicators?

    Science.gov (United States)

    Bainter, Sierra A.; Bollen, Kenneth A.

    2014-01-01

    In measurement theory, causal indicators are controversial and little understood. Methodological disagreement concerning causal indicators has centered on the question of whether causal indicators are inherently sensitive to interpretational confounding, which occurs when the empirical meaning of a latent construct departs from the meaning…

  15. Rationales in Children's Causal Learning from Others' Actions

    Science.gov (United States)

    Sobel, David M.; Sommerville, Jessica A.

    2009-01-01

    Shown commensurate actions and information by an adult, preschoolers' causal learning was influenced by the pedagogical context in which these actions occurred. Four-year-olds who were provided with a reason for an experimenter's action relevant to learning causal structure showed more accurate causal learning than children exposed to the same…

  16. 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…

  17. 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…

  18. How to Be Causal: Time, Spacetime and Spectra

    Science.gov (United States)

    Kinsler, Paul

    2011-01-01

    I explain a simple definition of causality in widespread use, and indicate how it links to the Kramers-Kronig relations. The specification of causality in terms of temporal differential equations then shows us the way to write down dynamical models so that their causal nature "in the sense used here" should be obvious to all. To extend existing…

  19. 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.

  20. 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 ...

  1. 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

  2. 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.

  3. 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}.

  4. 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.

  5. Consistence beats causality in recommender systems

    OpenAIRE

    Zhu, Xuzhen; Tian, Hui; 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 prefere...

  6. Gauge theory origins of supergravity causal structure

    CERN Document Server

    Kabat, D; Kabat, Daniel; Lifschytz, Gilad

    1999-01-01

    We discuss the gauge theory mechanisms which are responsible for the causal structure of the dual supergravity. For D-brane probes we show that the light cone structure and Killing horizons of supergravity emerge dynamically. They are associated with the appearance of new light degrees of freedom in the gauge theory, which we explicitly identify. This provides a picture of physics at the horizon of a black hole as seen by a D-brane probe.

  7. 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.

  8. 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.

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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.

  14. 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...

  15. 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

  16. [Causality in cardiology: concepts in evolution].

    Science.gov (United States)

    Méndez, Gustavo F

    2005-01-01

    This paper describes several concepts about causality from Empedocles, Aristoteles and Galeno, to Koch and Hill and the evolution of these concepts related to cardiovascular diseases. Also defines cause and risk, and the philosophical theories about scientific knowledge: inductive versus refutation analysis. On these basis, the study of cardiovascular disease's causality, especially coronary heart disease, allows us the identification of several risk factors involved in its development. However, even with the presently coronary heart disease risk charts (from Framingham and European studies) the higher probability for the development of a cardiovascular ischemic event is around 40%, establishing an important degree of uncertainty. With the improvement in molecular biology techniques, genetics have attempted to analyse several genetic polymorphisms in search of the origin of coronary heart disease. Unfortunately, less than 10% of these polymorphisms have had a positive correlation with coronary heart disease being of minor risk that those obtained for having the diagnosis of type 2 diabetes mellitus or hypercholesterolemia. On these basis, the requirement of new population research projects in which clinical and genetic risk factors are to be studied for the appropriate understanding of the causality process of cardiovascular diseases must be a worldwide priority.

  17. 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.

  18. 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.

  19. 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...

  20. 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...

  1. A developmental approach to learning causal models for cyber security

    Science.gov (United States)

    Mugan, Jonathan

    2013-05-01

    To keep pace with our adversaries, we must expand the scope of machine learning and reasoning to address the breadth of possible attacks. One approach is to employ an algorithm to learn a set of causal models that describes the entire cyber network and each host end node. Such a learning algorithm would run continuously on the system and monitor activity in real time. With a set of causal models, the algorithm could anticipate novel attacks, take actions to thwart them, and predict the second-order effects flood of information, and the algorithm would have to determine which streams of that flood were relevant in which situations. This paper will present the results of efforts toward the application of a developmental learning algorithm to the problem of cyber security. The algorithm is modeled on the principles of human developmental learning and is designed to allow an agent to learn about the computer system in which it resides through active exploration. Children are flexible learners who acquire knowledge by actively exploring their environment and making predictions about what they will find,1, 2 and our algorithm is inspired by the work of the developmental psychologist Jean Piaget.3 Piaget described how children construct knowledge in stages and learn new concepts on top of those they already know. Developmental learning allows our algorithm to focus on subsets of the environment that are most helpful for learning given its current knowledge. In experiments, the algorithm was able to learn the conditions for file exfiltration and use that knowledge to protect sensitive files.

  2. Structure and Connectivity Analysis of Financial Complex System Based on G-Causality Network

    Science.gov (United States)

    Xu, Chuan-Ming; Yan, Yan; Zhu, Xiao-Wu; Li, Xiao-Teng; Chen, Xiao-Song

    2013-11-01

    The recent financial crisis highlights the inherent weaknesses of the financial market. To explore the mechanism that maintains the financial market as a system, we study the interactions of U.S. financial market from the network perspective. Applied with conditional Granger causality network analysis, network density, in-degree and out-degree rankings are important indicators to analyze the conditional causal relationships among financial agents, and further to assess the stability of U.S. financial systems. It is found that the topological structure of G-causality network in U.S. financial market changed in different stages over the last decade, especially during the recent global financial crisis. Network density of the G-causality model is much higher during the period of 2007-2009 crisis stage, and it reaches the peak value in 2008, the most turbulent time in the crisis. Ranked by in-degrees and out-degrees, insurance companies are listed in the top of 68 financial institutions during the crisis. They act as the hubs which are more easily influenced by other financial institutions and simultaneously influence others during the global financial disturbance.

  3. 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.

  4. Método para preservação da viabilidade e atividade antagônica de Trichoderma stromaticum , agente de biocontrole da vassoura-de-bruxa do cacaueiro Method for preservation of viability and antagonic activity of Trichoderma stromaticum, biocontrol agent of witches´broom disease of cocoa

    Directory of Open Access Journals (Sweden)

    Cleber Novais Bastos

    2008-09-01

    Full Text Available Avaliou-se a viabilidade da massa esporógena de Trichoderma stromaticum, através do crescimento micelial em meio de cultivo e a atividade antagônica (parasitária em vassouras secas de cacaueiro, após a preservação de quatro isolados (Ts1606, Ts3107, Ts0108, Ts2705 do antagonista por quatro anos em fragmentos de vassoura secas, acondicionados em tubos de ensaio e mantidos em refrigerador com temperatura aproximada de 5 °C. Todos os isolados preservados apresentaram-se viáveis, com crescimento e esporulação normais e continuavam antagônicos a Crinipellis perniciosa. Os resultados obtidos indicam a eficiência do método, que é capaz de manter os isolados de T. stromaticum viáveis por longos períodos de tempo, preservando características morfológicas, fisiológicas e antagônicas.After four years of preservation by using dried cocoa brooms in fridge at 5 °C, the viability of four isolates (Ts1606, Ts3107, Ts0108, Ts2705 of Trichoderma stromaticum was evaluated based on germination of conidia, mycelium growth in a culture medium and antagonistic activity on dry cocoa brooms. All the isolates preserved maintained viability, showing normal growth, sporulation and antagonistic activity against Crinipellis perniciosa.. These results indicate the efficience of the method for the long term preservation of T. stromaticum, maintaining their morphological, physiological, and antagonistic characteristics.

  5. Infraestrutura de biossegurança para agentes biológicos em hospitais do sul do Estado da Bahia, Brasil Infraesctructura de bioseguridad para los agentes biológicos en hospitales del sur del Estado de Bahia, Brasil Biosecurity infrastructure for biological agents in hospitals from the south of Bahia State, Brazil

    OpenAIRE

    Maridalva de Souza Penteado; Tânia Cristina de Oliveira

    2010-01-01

    O objetivo do estudo foi descrever a infraestrutura de biossegurança em hospitais localizados na Região Sul do Estado da Bahia, Brasil. Tratou-se de um estudo descritivo-exploratório realizado em comissões de controle de infecções hospitalares e comissão institucional de prevenção a acidentes quanto à existência de normas escritas, realização de treinamentos para essas mesmas preconizações, existência de registros institucionais concernentes à biossegurança e existência de práticas de atenção...

  6. Aspectos morfológicos da colonização de Colletotrichum gloeosporioides em órgãos de plantas de cafeeiros e com sintomas da mancha manteigosa Morphologic aspects of colonization of Colletotrichum gloeosporioides on organs of coffee plants with blister spot

    Directory of Open Access Journals (Sweden)

    Josimar Batista Ferreira

    2009-08-01

    Full Text Available Objetivou-se, no presente trabalho, analisar microscopicamente a colonização de C. gloeosporioides, agente da mancha manteigosa (MM, em condições naturais da doença, sobre os diferentes órgãos e tecidos da cultivar Catucaí Vermelho: folhas, pecíolos, nervuras, ramos, frutos e pedúnculos. Todas as amostras foram processadas, obtendo-se imagens em microscópico eletrônico de varredura. Os ramos e as nervuras de folhas de cafeeiros com mancha manteigosa apresentando morte descendente e hipocótilos oriundos de sementes têm os vasos do xilema, floema e células do córtex colonizados por C. gloeosporioides, já os frutos com sintoma da mancha manteigosa apresentaram colonização nos tecidos do exocarpo, mesocarpo, endocarpo e endosperma.The aim of this work was to study the colonization of leaves, petioles, veins, branches, fruits, and peduncles by C. gloeosporioides, the causal agent of blister spot, under natural infections of cultivar Catucaí Vermelho in field conditions. All materials were analyzed through scanning electron microscopy. The branches and veins of coffee leaves affected by blister spot with descending death as well as hypocotyls from seedlings had their xylem, phloem and cortical cells colonized by C. gloeosporioides while fruits showing blister spot symptoms had their exocarp, mesocarp, endocarp, and endosperm tissues colonized by C. gloeosporioides.

  7. A práxis do agente comunitário de saúde no contexto do programa saúde da família: reflexões estratégicas The community health agent's praxis in the context of the family health program: strategic reflections

    Directory of Open Access Journals (Sweden)

    Karine de Oliveira Gomes

    2009-12-01

    Full Text Available O Programa Saúde da Família (PSF surgiu no cenário brasileiro como estratégia de superação do modelo assistencial centrado na doença e no cuidado médico individualizado. Nesse contexto, os agentes comunitários de saúde (ACS têm sido considerados atores-chave na implantação de políticas voltadas para a reorientação do modelo de atenção à saúde. O objetivo deste estudo foi analisar as concepções e percepções sobre o SUS e o PSF que norteiam as ações dos ACS, refletindo sobre sua função e formação profissional. O trabalho fundamentou-se na pesquisa quali-quantitativa, foi realizado em Cajuri-MG e foram entrevistados todos os ACS (n=11 que trabalhavam no PSF. Os resultados demonstraram que a maioria dos ACS (72,7% residia na comunidade em que atuava, trabalhava há mais de cinco anos no PSF e acompanhava a quantidade de famílias recomendada. Entre as principais funções, destacaram-se visitas domiciliares, busca ativa e educação em saúde, que na maioria das vezes acontecia de forma individualizada e centrada no reforço da assistência médica e na prevenção de riscos específicos. Em relação à capacitação, 54,6% dos ACS receberam orientação antes de iniciar o trabalho e 81,8% participaram de cursos depois que já estavam trabalhando. Apenas 27,3% dos ACS souberam conceituar o SUS e 36,4% demonstraram entendimento adequado sobre PSF. Esses resultados demonstram a necessidade de maiores esforços para melhorar a capacitação do ACS, visando adequar seu nível de apreensão e conhecimento dos princípios do SUS e PSF, para que ele possa atuar segundo as diretrizes desse sistema e contribuir efetivamente para sua consolidação.Programa Saúde da Família (PSF - Family Health Program appeared in the Brazilian scenario as a strategy to overcome an assistance model that is centered on disease and on individualized medical care. In this context, the agentes comunitários de saúde (ACS - community health agents

  8. 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 ...

  9. Alterações funcionais da junção neuromuscular provocadas em ratos pela administração diária e prolongada de um agente curarizante

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Zanini

    1967-06-01

    Full Text Available A ratos adultos, machos, foi administrado durante 8 semanas, uma vez ao dia, o iodeto do dimetiléter da d-tubocurarina (DMT, pela via intraperitoneal. Os animais foram distribuídos em 3 lotes: os do 1.°, receberam 5,5 gama de DMT/kg/dia; os do 2.°, 16,6 gama/kg/dia; os do 3.° (controle, 1 ml da solução isotônica de cloreto de sódio. A força muscular dos animais foi avaliada uma vez por semana, de acordo com o método descrito no texto, antes e após a injeção intraperitoneal da referida substância. Com o decorrer da experimentação, observou-se que: a houve diminuição significativa da força muscular dos animais, avaliada após esvaecimento da atividade curarizante do DMT; b a determinação da força muscular, feita logo após a injeção, mostrou que a dose de 5,5 gama/kg/dia provoca um aumento da suscetibilidade dos animais à ação curarizante do DMT; c o efeito inibidor provocado pela dose de 16,6 gama/kg/dia de DMT aumentou no início mas diminuiu significantemente após a 5ª semana, muito embora houvesse uma progressiva diminuição da força muscular, sugerindo independência entre os dois efeitos. Com base nesses resultados, são discutidos alguns fenômenos que podem ocorrer na instalação e tratamento da miastenia grave.

  10. 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

  11. 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.

  12. 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.

  13. Bianchi-I cosmology from causal thermodynamics

    CERN Document Server

    Bittencourt, Eduardo; Klippert, Renato

    2016-01-01

    We investigate diagonal Bianchi-I spacetimes in the presence of viscous fluids by using the shear and the anisotropic pressure components as the basic variables, where the viscosity is driven by the (second-order) causal thermodynamics. A few exact solutions are presented, among which we mention the anisotropic versions of de Sitter/anti-de Sitter geometries as well as an asymptotically isotropic spacetime presenting an effective constant cosmic acceleration without any cosmological constant. The qualitative analysis of the solutions for barotropic fluids with linear equations of state suggests that the behaviour is quite general.

  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. 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

  16. Análisis proteómico de Plasmodium, el agente causal de la malaria Proteomic analysis of Plasmodium, the causal agent of Malaria

    Directory of Open Access Journals (Sweden)

    Ivone Castro R

    2009-01-01

    Full Text Available Los plasmodios son protozoarios cuyo complejo ciclo de vida se lleva a cabo en dos hospederos, el vertebrado y el mosquito. La infección de los seres humanos produce la enfermedad conocida como malaria. La secuenciación del genoma de Plasmodium falciparum y el desarrollo de la proteómica han permitido un gran avance en el conocimiento de la biología de este letal parásito. La presente revisión se centra en describir los logros recientes en el estudio del proteoma de Plasmodium falciparum y algunas de las implicaciones en la búsqueda de nuevos fármacos antimaláricos, así como en la generación de vacunas para el control de la enfermedad.Plasmodia are protozoa whose complex life cycle takes place in two different hosts, the vertebrate and the mosquito. The human infection produces the malaria disease. The genome sequence of Plasmodium falciparum and the proteomic tools have enabled a huge advance in knowledge of the biology of this parasite. This review will focus on the recent advances in proteomic studies of Plasmodium falciparum and some implications for the search of new antimalarial drugs as well as vaccines for the control of the disease.

  17. Molecular diagnosis of Anaplasmataceae organisms in dogs with clinical and microscopical signs of ehrlichiosis Diagnóstico molecular de agentes da família Anaplasmataceae em cães com sinais clínicos e microscópios de erliquiose

    Directory of Open Access Journals (Sweden)

    Ana Sílvia Dagnone

    2009-12-01

    Full Text Available Ehrlichioses are important emerging zoonotic tick-borne diseases that can affect both animals and humans. Clinical manifestations of ehrlichiosis caused by different members of Anaplasmataceae in dogs are similar to each other and to other diseases showing systemic manifestation. The observation of inclusions in white blood cells and in platelets cannot be used to confirm the Anaplasmataceae etiologic agent of the disease. In this work we assessed the presence of Anaplasmataceae agents in 51 dogs from two different cities (Jaboticabal and Campo Grande showing clinical and microscopical diagnosis of ehrlichiosis, by using molecular techniques. Anaplasmataceae DNA were amplified in 46/51 (90.2% of the blood samples; 22 (40% samples from Jaboticabal and 10 (18.2% from Campo Grande were positive for E. canis nPCR. Anaplasma platys DNA was amplified in 2 samples from Jaboticabal and in 11 from Campo Grande. Phylogenetic analysis of E. canis and A. platys DNA confirmed the infection agent and showed that PCR is the most reliable method to diagnose ehrlichial infection.Erliquioses são importantes enfermidades emergentes transmitidas por carrapatos que podem afetar os animais e o homem. Em cães, as manifestações clínicas da erliquiose causada por diferentes membros da Família Anaplasmataceae são similares entre si e entre outras enfermidades de manifestação sistêmica. A observação de inclusões em leucócitos e plaquetas não pode ser utilizada para diagnosticar o agente etiológico pertencente à Família Anaplasmataceae. O presente trabalho objetivou detectar, por meio de técnicas moleculares, a presença de agentes da Família Anaplasmataceae em 51 cães de duas diferentes cidades (Jaboticabal, SP e Campo Grande, MS apresentando sinais clínicos e microscópios sugestivos de erliquiose. DNA de agentes da Família Anaplasmataceae foi amplificado em 46/51 (90,2% das amostras de sangue; 22 (40% amostras de Jaboticabal e 10 (18,2% amostras

  18. God Does Not Play Dice: Causal Determinism and Preschoolers' Causal Inferences

    Science.gov (United States)

    Schulz, Laura E.; Sommerville, Jessica

    2006-01-01

    Three studies investigated children's belief in causal determinism. If children are determinists, they should infer unobserved causes whenever observed causes appear to act stochastically. In Experiment 1, 4-year-olds saw a stochastic generative cause and inferred the existence of an unobserved inhibitory cause. Children traded off inferences…

  19. 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

  20. 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.…

  1. 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…

  2. Shear bond strength after dentin bleaching with 10% carbamide peroxide agents Resistência ao cisalhamento da dentina após clareamento com peróxido de carbamida a 10%

    OpenAIRE

    Roberta Tarkany Basting; Patrícia Moreira de Freitas; Luiz André Freire Pimenta; Mônica Campos Serra

    2004-01-01

    This in vitro study evaluated the shear bond strength (SBS) of dentin treated with two 10% carbamide peroxide bleaching agents 15 days after bleaching and storage in artificial saliva. Dentin fragments were randomly divided into 3 groups (n = 20) for the treatment with the two different bleaching agents (Rembrandt 10% or Opalescence 10%) or with a placebo agent, applied to the tooth surface for 8 hours a day. During the remaining time, the specimens were stored in artificial saliva. After 42 ...

  3. 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

  4. 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. ...

  5. Immunity in arterial hypertension: associations or causalities?

    Science.gov (United States)

    Anders, Hans-Joachim; Baumann, Marcus; Tripepi, Giovanni; Mallamaci, Francesca

    2015-12-01

    Numerous studies describe associations between markers of inflammation and arterial hypertension (aHT), but does that imply causality? Interventional studies that reduce blood pressure reduced also markers of inflammation, but does immunosuppression improve hypertension? Here, we review the available mechanistic data. Aberrant immunity can trigger endothelial dysfunction but is hardly ever the primary cause of aHT. Innate and adaptive immunity get involved once hypertension has caused vascular wall injury as immunity is a modifier of endothelial dysfunction and vascular wall remodelling. As vascular remodelling progresses, immunity-related mechanisms can become significant cofactors for cardiovascular (CV) disease progression; vice versa, suppressing immunity can improve hypertension and CV outcomes. Innate and adaptive immunity both contribute to vascular wall remodelling. Innate immunity is driven by danger signals that activate Toll-like receptors and other pattern-recognition receptors. Adaptive immunity is based on loss of tolerance against vascular autoantigens and includes autoreactive T-cell immunity as well as non-HLA angiotensin II type 1 receptor-activating autoantibodies. Such processes involve numerous other modulators such as regulatory T cells. Together, immunity is not causal for hypertension but rather an important secondary pathomechanism and a potential therapeutic target in hypertension.

  6. 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.

  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. 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

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. Agent, autonomous

    OpenAIRE

    Luciani, Annie

    2007-01-01

    The expression autonomous agents, widely used in virtual reality, computer graphics, artificial intelligence and artificial life, corresponds to the simulation of autonomous creatures, virtual (i.e. totally computed by a program), or embodied in a physical envelope, as done in autonomous robots.

  14. Effect of a New Prokinetic Agent DA-9701 Formulated with Corydalis Tuber and Pharbitidis Semen on Cytochrome P450 and UDP-Glucuronosyltransferase Enzyme Activities in Human Liver Microsomes

    Directory of Open Access Journals (Sweden)

    Hye Young Ji

    2012-01-01

    Full Text Available DA-9701 is a new botanical drug composed of the extracts of Corydalis tuber and Pharbitidis semen, and it is used as an oral therapy for the treatment of functional dyspepsia in Korea. The inhibitory potentials of DA-9701 and its component herbs, Corydalis tuber and Pharbitidis semen, on the activities of seven major human cytochrome P450 (CYP enzymes and four UDP-glucuronosyltransferase (UGT enzymes in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. DA-9701 and Corydalis tuber extract slightly inhibited UGT1A1-mediated etoposide glucuronidation, with 50% inhibitory concentration (IC50 values of 188 and 290 μg/mL, respectively. DA-9701 inhibited CYP2D6-catalyzed bufuralol 1′-hydroxylation with an inhibition constant (Ki value of 6.3 μg/mL in a noncompetitive manner. Corydalis tuber extract competitively inhibited CYP2D6-mediated bufuralol 1′-hydroxylation, with a Ki value of 3.7 μg/mL, whereas Pharbitidis semen extract showed no inhibition. The volume in which the dose could be diluted to generate an IC50 equivalent concentration (volume per dose index value of DA-9701 for inhibition of CYP2D6 activity was 1.16 L/dose, indicating that DA-9701 may not be a potent CYP2D6 inhibitor. Further clinical studies are warranted to evaluate the in vivo extent of the observed in vitro interactions.

  15. A difícil interface controle de vetores - atenção básica: inserção dos agentes de controle de vetores da dengue junto às equipes de saúde das unidades básicas no município de São José do Rio Preto, SP

    Directory of Open Access Journals (Sweden)

    Marisa Bernardi Cesarino

    2014-09-01

    Full Text Available Este estudo analisa o processo de inserção dos agentes de controle de vetores nas unidades básicas de saúde (UBS em São José do Rio Preto-SP, designados agentes de saúde (AS, com o objetivo de melhorar a eficácia do programa de controle da dengue. Trata-se de um estudo de caso, baseado na observação direta e no registro das falas dos participantes de fóruns promovidos pela Secretária de Saúde do município com esses profissionais. Realizou-se a análise de conteúdo desses registros, identificando-se cinco categorias: inserção social; integralidade da atenção; intersetorialidade; valorização dos AS; e educação permanente. Os profissionais expressaram a necessidade dos fóruns de discussão serem permanentes; as dificuldades para realizar ações intersetoriais; e o sentimento de valorização profissional por participar das equipes das UBS e por colaborar com a participação comunitária. O estudo possibilitou compreender como ocorreu a inserção dos AS na atenção básica do município e a complexidade do controle da dengue nesse nível de atenção, que envolve questões socioambientais e ações intersetoriais. O estudo revelou as diversas possibilidades de atuação dos AS e a pertinência da sua inserção na atenção básica.

  16. Linkage intensity learning approach with genetic algorithm for causality diagram

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng-liang; CHEN Juan-juan

    2007-01-01

    The causality diagram theory, which adopts graphical expression of knowledge and direct intensity of causality, overcomes some shortages in belief network and has evolved into a mixed causality diagram methodology for discrete and continuous variable. But to give linkage intensity of causality diagram is difficult, particularly in many working conditions in which sampling data are limited or noisy. The classic learning algorithm is hard to be adopted. We used genetic algorithm to learn linkage intensity from limited data. The simulation results demonstrate that this algorithm is more suitable than the classic algorithm in the condition of sample shortage such as space shuttle's fault diagnoisis.

  17. Granger causality and transfer entropy are equivalent for Gaussian variables.

    Science.gov (United States)

    Barnett, Lionel; Barrett, Adam B; Seth, Anil K

    2009-12-01

    Granger causality is a statistical notion of causal influence based on prediction via vector autoregression. Developed originally in the field of econometrics, it has since found application in a broader arena, particularly in neuroscience. More recently transfer entropy, an information-theoretic measure of time-directed information transfer between jointly dependent processes, has gained traction in a similarly wide field. While it has been recognized that the two concepts must be related, the exact relationship has until now not been formally described. Here we show that for Gaussian variables, Granger causality and transfer entropy are entirely equivalent, thus bridging autoregressive and information-theoretic approaches to data-driven causal inference.

  18. Granger causality and transfer entropy are equivalent for Gaussian variables

    CERN Document Server

    Barnett, Lionel; Seth, Anil

    2009-01-01

    Granger causality is a statistical notion of causal influence based on prediction via vector autoregression. Developed originally in the field of econometrics, it has since found application in a broader arena, particularly in neuroscience. More recently transfer entropy, an information-theoretic measure of time-directed information transfer between jointly dependent processes, has gained traction in a similarly wide field. It has always seemed plausible that the two concepts ought to be related. Here we show that for Gaussian variables, Granger causality and transfer entropy are entirely equivalent, thus bridging autoregressive and information-theoretic approaches to data-driven causal inference.

  19. 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

  20. Severidade da podridão-verde em inhames e especialização fisiológica em Penicillium sclerotigenum Severity of green rot in yellow and water yams and the physiological specialization of Penicillium sclerotigenum

    OpenAIRE

    Idjane S. Oliveira; Edna Dora. M. N. Luz; José Luiz Bezerra; Romero M. de Moura; Gustavo R. C. Torres; Leonor C. Maia

    2006-01-01

    Estudaram-se as reações do inhame Dioscorea alata cv. São Tomé e D. cayennensis cv. Da Costa em relação à severidade da podridão-verde, causada pelo fungo Penicillium sclerotigenum. Ao mesmo tempo, foi pesquisada à ocorrência de especialização fisiológica do agente causal, em relação à patogenicidade, nas mencionadas espécies de inhame. Para complementar esse estudo, analisou-se, in vitro, o crescimento micelial de P. sclerotigenum em três meios de cultura semi-sintéticos, sendo dois à base d...

  1. Infraestrutura de biossegurança para agentes biológicos em hospitais do sul do Estado da Bahia, Brasil Infraesctructura de bioseguridad para los agentes biológicos en hospitales del sur del Estado de Bahia, Brasil Biosecurity infrastructure for biological agents in hospitals from the south of Bahia State, Brazil

    Directory of Open Access Journals (Sweden)

    Maridalva de Souza Penteado

    2010-10-01

    Full Text Available O objetivo do estudo foi descrever a infraestrutura de biossegurança em hospitais localizados na Região Sul do Estado da Bahia, Brasil. Tratou-se de um estudo descritivo-exploratório realizado em comissões de controle de infecções hospitalares e comissão institucional de prevenção a acidentes quanto à existência de normas escritas, realização de treinamentos para essas mesmas preconizações, existência de registros institucionais concernentes à biossegurança e existência de práticas de atenção à saúde dos profissionais e isolamentos de pacientes. Os hospitais são comparados segundo a presença de cada um dos itens analisados de acordo com sua classificação por porte, vinculação jurídico-financeira, dentre outras. Conclui-se que a situação geral é precária quanto à presença dos itens investigados, o que impele a considerar a necessidade de que se leve em conta, numa análise de qualidade hospitalar, também o cuidado com a vida dos seus trabalhadores.El objetivo del estudio fue describir la infraestructura de bioseguridad en hospitales de la Región Sur del Estado de Bahia, Brasil. Fue realizada una investigación descriptiva-exploratória en las comisiones de control de infecciones hospitalarios y en las comisiónes institucionales de prevención de accidentes sobre la existencia de normas escritas, la realización de entrenamientos para esas mismas preconizaciones, la existencia de registros institucionales concernientes a la bioseguridad, la existencia de practicas de atención a la salud de los profesionales y apartamiento de pacientes. Los hospitales son son comparados según la presencia de cada uno de los itens analizados en conformidad con su porte, vinculación jurídico financiera, entre otras. Se concluye que la situación general es precaria cuanto a la presencia de los itens investigados, lo que lleva a considerar la necesidad de que se lleve en cuenta, la análisis de la calidad hospitalario, tambi

  2. 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. PMID:27594846

  3. Quantum Causality, Stochastics, Trajectories and Information

    CERN Document Server

    Belavkin, V P

    2002-01-01

    A history of the discovery of quantum mechanics and paradoxes of its interpretation is reconsidered from the modern point of view of quantum stochastics and information. It is argued that in the orthodox quantum mechanics there is no place for quantum phenomenology such as events. The development of quantum measurement theory, initiated by von Neumann, and Bell's conceptual critics of hidden variable theories indicated a possibility for resolution of this crisis. This can be done by divorcing the algebra of the dynamical generators and an extended algebra of the potential (quantum) and the actual (classical) observables. The latter, called beables, form the center of the algebra of all observables, as the only visible (macroscopic) observables must be compatible with any hidden (microscopic) observable. It is shown that within this approach quantum causality can be rehabilitated within an extended quantum mechanics (eventum mechanics) in the form of a superselection rule for compatibility of the consistent hi...

  4. 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.

  5. 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...

  6. Causal structure and electrodynamics on Finsler spacetimes

    Science.gov (United States)

    Pfeifer, Christian; Wohlfarth, Mattias N. R.

    2011-08-01

    We present a concise new definition of Finsler spacetimes that generalizes Lorentzian metric manifolds and provides consistent backgrounds for physics. Extending standard mathematical constructions known from Finsler spaces, we show that geometric objects like the Cartan nonlinear connection and its curvature are well defined almost everywhere on Finsler spacetimes, including their null structure. This allows us to describe the complete causal structure in terms of timelike and null curves; these are essential to model physical observers and the propagation of light. We prove that the timelike directions form an open convex cone with a null boundary, as is the case in Lorentzian geometry. Moreover, we develop action integrals for physical field theories on Finsler spacetimes, and tools to deduce the corresponding equations of motion. These are applied to construct a theory of electrodynamics that confirms the claimed propagation of light along Finsler null geodesics.

  7. Causal structure and electrodynamics on Finsler spacetimes

    CERN Document Server

    Pfeifer, Christian

    2011-01-01

    We present a concise new definition of Finsler spacetimes that generalize Lorentzian metric manifolds and provide consistent backgrounds for physics. Extending standard mathematical constructions known from Finsler spaces we show that geometric objects like the Cartan non-linear connection and its curvature are well-defined almost everywhere on Finsler spacetimes, also on their null structure. This allows us to describe the complete causal structure in terms of timelike and null curves; these are essential to model physical observers and the propagation of light. We prove that the timelike directions form an open convex cone with null boundary as is the case in Lorentzian geometry. Moreover, we develop action integrals for physical field theories on Finsler spacetimes, and tools to deduce the corresponding equations of motion. These are applied to construct a theory of electrodynamics that confirms the claimed propagation of light along Finsler null geodesics.

  8. 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...

  9. Equity Theory Ratios as Causal Schemas

    Directory of Open Access Journals (Sweden)

    Alexios Arvanitis

    2016-08-01

    Full Text Available 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.

  10. 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.)

  11. 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.

  12. 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

  13. Assessing thalamocortical functional connectivity with Granger causality.

    Science.gov (United States)

    Chen, Cheng; Maybhate, Anil; Israel, David; Thakor, Nitish V; Jia, Xiaofeng

    2013-09-01

    Assessment of network connectivity across multiple brain regions is critical to understanding the mechanisms underlying various neurological disorders. Conventional methods for assessing dynamic interactions include cross-correlation and coherence analysis. However, these methods do not reveal the direction of information flow, which is important for studying the highly directional neurological system. Granger causality (GC) analysis can characterize the directional influences between two systems. We tested GC analysis for its capability to capture directional interactions within both simulated and in vivo neural networks. The simulated networks consisted of Hindmarsh-Rose neurons; GC analysis was used to estimate the causal influences between two model networks. Our analysis successfully detected asymmetrical interactions between these networks ( , t -test). Next, we characterized the relationship between the "electrical synaptic strength" in the model networks and interactions estimated by GC analysis. We demonstrated the novel application of GC to monitor interactions between thalamic and cortical neurons following ischemia induced brain injury in a rat model of cardiac arrest (CA). We observed that during the post-CA acute period the GC interactions from the thalamus to the cortex were consistently higher than those from the cortex to the thalamus ( 1.983±0.278 times higher, p = 0.021). In addition, the dynamics of GC interactions between the thalamus and the cortex were frequency dependent. Our study demonstrated the feasibility of GC to monitor the dynamics of thalamocortical interactions after a global nervous system injury such as CA-induced ischemia, and offers preferred alternative applications in characterizing other inter-regional interactions in an injured brain.

  14. 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

  15. 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.

  16. Interferência do tratamento preventivo com antimicrobianos sobre a colonização de agentes da microbiota do trato respiratório de leitões

    OpenAIRE

    Lara, Anne Caroline de

    2012-01-01

    Resumo: Os agentes Streptococcus suis, Haemophilus parasuis e Actinobacillus pleuropneumoniae são responsáveis por grandes prejuízos na suinocultura tecnificada. Estes agentes podem causar meningite estreptocócica, doença de Glasser ou pneumonias, respectivamente. Essas doenças são consideradas multifatoriais, pois somente a presença dos agentes na granja não é suficiente para desencadear a doença. Portanto, a presença de fatores de risco associado à cepas potencialmente patogênicas represent...

  17. 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.

  18. 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.

  19. 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…

  20. The Feasibility of Using Causal Indicators in Educational Measurement

    Science.gov (United States)

    Wang, Jue; Engelhard, George, Jr.

    2016-01-01

    The authors of the focus article describe an important issue related to the use and interpretation of causal indicators within the context of structural equation modeling (SEM). In the focus article, the authors illustrate with simulated data the effects of omitting a causal indicator. Since SEMs are used extensively in the social and behavioral…

  1. 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…

  2. 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…

  3. 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.

  4. 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…

  5. 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…

  6. 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…

  7. 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…

  8. 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…

  9. Effect of fungicides and alternative products in control of anthracnose and black spot of guavaEfeito de fungicidas e produtos alternativos no controle da antracnose e da pinta preta da goiaba

    Directory of Open Access Journals (Sweden)

    Ivan Herman Fischer

    2012-12-01

    Full Text Available This work aimed to evaluate the efficiency of fungicides in controlling in vitro and in vivo the causal agents of anthracnose (Colletotrichum gloeosporioides and C. acutatum and black spot (Guignardia psidii and evaluate the effect of alternative products to control these diseases. Inhibition of mycelial growth of the pathogens was evaluated for ten fungicides at concentrations of 1, 10 and 100 mg L-1 of active ingredient in potato-dextrose-agar medium. The effectiveness of the fungicides azoxystrobin + difenoconazole, cyproconazole, pyraclostrobin, tebuconazole and tebuconazole + trifloxystrobin in controlling disease incidence and severity of anthracnose, through applications in the field, was measured in fruits collected at three stages of maturation, according to the skin color (dark green, light green and yellowish green. In postharvest dipping of fruits, the products evaluated were citric acid, peracetic acid, salicylic acid, sodium bicarbonate, chlorine dioxide, Ecolife® and chitosan. The fungicides azoxystrobin + difenoconazole, pyraclostrobin, tebuconazole and trifloxystrobin + tebuconazole were highly effective in inhibiting the in vitro mycelial growth of G. psidii and moderately to highly effective in inhibiting C. acutatum and C. gloeosporioides. In field conditions, the fungicide azoxystrobin + difenoconazole was effective in controlling anthracnose and black spot in fruit at three maturity stage (skin color yellowish green. The alternative products tested were ineffective in the curative control of anthracnose and early blight at postharvest of guava. Os objetivos deste trabalho foram avaliar a eficiência de fungicidas no controle in vitro e in vivo dos agentes causais da antracnose (Colletotrichum gloeosporioides e C. acutatum e da pinta preta (Guignardia psidii da goiaba e avaliar o efeito de produtos alternativos no controle pós-colheita destas doenças. A inibição do crescimento micelial dos patógenos foi avaliada para

  10. Análise da redistribuição de calor com agentes inalatórios, em ratos submetidos a laparotomia e pneumoperitônio, através da termografia infravermelha Análisis de la redistribución de calor con agentes inhalatorios, en ratones sometidos a laparotomia y pneumoperitonio, a través de termografia infraroja Analysis of heat loss using inhalation agents in rats subjected to laparotomy and increased intra-abdominal pressure, using digital infrared thermal image

    Directory of Open Access Journals (Sweden)

    Daniel Colman

    2002-06-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: A Anestesiologia envolve o manuseio de situações inerentes ao ato anestésico e operatório que cursam com o desequilíbrio da homeostase térmica do paciente, ocasionando efeitos fisiológicos deletérios. O presente estudo objetiva qualificar e quantificar os fenômenos de redistribuição térmica em ratos submetidos à anestesia inalatória, durante a indução, e em situações cirúrgicas de laparotomia e pneumoperitônio. MÉTODO: Foram utilizados 90 ratos, que foram submetidos à anestesia inalatória, distribuídos em três grupos, em que foram utilizados: halotano, isoflurano e sevoflurano. Em cada grupo houve divisão em outros três sub-grupos: I - controle, II - laparotomia mediana com exposição de alças intestinais; III - pneumoperitônio de 15 mmHg. A análise termodinâmica realizou-se de duas formas: através da temperatura central esofágica e da imagem digital térmica infravermelha. RESULTADOS: Não houve diferença significativa em relação aos anestésicos inalatórios entre os grupos I e II em relação a perda de calor. Em relação ao grupo III, houve diferença entre o isoflurano e o sevoflurano, sendo o isoflurano o anestésico responsável pela maior perda de temperatura no animal. CONCLUSÕES: O sevoflurano foi o agente anestésico inalatório que determinou menor perda de calor frente ao pneumoperitônio, em relação ao isoflurano e halotano.JUSTIFICATIVA Y OBJETIVOS: La Anestesiología envuelve el manoseo de situaciones inherentes al acto anestésico y operatorio que cursan con el desequilibrio de la homeóstasis térmica del paciente, ocasionando efectos fisiológicos deletéreos. El presente estudio objetiva calificar y cuantificar los fenómenos de redistribución térmica en ratones sometidos a anestesia inhalatoria, durante la inducción, y en situaciones quirúrgicas de laparotomia y pneumoperitonio. MÉTODO: Fueron utilizados 90 ratones, sometidos a anestesia inhalatoria

  11. Bell's theorem and the causal arrow of time

    Science.gov (United States)

    Argaman, Nathan

    2010-10-01

    Einstein held that the formalism of quantum mechanics involves "spooky actions at a distance." In the 1960s, Bell amplified this by showing that the predictions of quantum mechanics disagree with the results of any locally causal description. It should be appreciated that accepting nonlocal descriptions while retaining causality leads to a clash with relativity. Furthermore, the causal arrow of time by definition contradicts time-reversal symmetry. For these reasons, Wheeler and Feynman, Costa de Beauregard, Cramer, Price, and others have advocated abandoning microscopic causality. In this paper, a simplistic but concrete example of this line of thought is presented, in the form of a retro-causal toy model that is stochastic and provides an appealing description of the quantum correlations discussed by Bell. It is concluded that Einstein's "spooky actions" may occur "in the past" rather than "at a distance," resolving the tension between quantum mechanics and relativity and opening unexplored possibilities for future reformulations of quantum mechanics.

  12. Mitigating the effects of measurement noise on Granger causality

    CERN Document Server

    Nalatore, Hariharan; Ding, Mingzhou

    2007-01-01

    Computing Granger causal relations among bivariate experimentally observed time series has received increasing attention over the past few years. Such causal relations, if correctly estimated, can yield significant insights into the dynamical organization of the system being investigated. Since experimental measurements are inevitably contaminated by noise, it is thus important to understand the effects of such noise on Granger causality estimation. The first goal of this paper is to provide an analytical and numerical analysis of this problem. Specifically, we show that, due to noise contamination, (1) spurious causality between two measured variables can arise and (2) true causality can be suppressed. The second goal of the paper is to provide a denoising strategy to mitigate this problem. Specifically, we propose a denoising algorithm based on the combined use of the Kalman filter theory and the Expectation-Maximization (EM) algorithm. Numerical examples are used to demonstrate the effectiveness of the den...

  13. 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.

  14. Causal Relationship Between Relative Price Variability and Inflation in Turkey:

    Directory of Open Access Journals (Sweden)

    Nebiye Yamak

    2016-09-01

    Full Text Available This study investigates the causal relationship between inflation and relative price variability in Turkey for the period of January 2003-January 2014, by using panel data. In the study, a Granger (1969 non-causality test in heterogeneous panel data models developed by Dumitrescu and Hurlin (2012 is utilized to determine the causal relations between inflation rate relative price variability. The panel data consists of 4123 observations: 133 time observations and 31 cross-section observations. The results of panel causality test indicate that there is a bidirectional causality between inflation rate and relative price variability by not supporting the imperfection information model of Lucas and the menu cost model of Ball and Mankiw.

  15. Statistical causal inferences and their applications in public health research

    CERN Document Server

    Wu, Pan; Chen, Ding-Geng

    2016-01-01

    This book compiles and presents new developments in statistical causal inference. The accompanying data and computer programs are publicly available so readers may replicate the model development and data analysis presented in each chapter. In this way, methodology is taught so that readers may implement it directly. The book brings together experts engaged in causal inference research to present and discuss recent issues in causal inference methodological development. This is also a timely look at causal inference applied to scenarios that range from clinical trials to mediation and public health research more broadly. In an academic setting, this book will serve as a reference and guide to a course in causal inference at the graduate level (Master's or Doctorate). It is particularly relevant for students pursuing degrees in Statistics, Biostatistics and Computational Biology. Researchers and data analysts in public health and biomedical research will also find this book to be an important reference.

  16. 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...

  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. Causality Assessment in Premarketing Drug Clinical Trials: Regulatory Evolution in the USA and Ongoing Concerns.

    Science.gov (United States)

    Goldman, Stephen A

    2016-10-01

    Since 1993, how to assess the causality of serious adverse events in premarketing drug clinical trials has undergone sustained regulatory evolution in the USA. In that year, an investigational drug study for chronic hepatitis B virus infection was emergently stopped after a patient suddenly exhibited hepatic failure and lactic acidosis, which later developed, along with pancreatitis and peripheral neuropathy, in several others after drug discontinuation. Five patients eventually died, including three despite emergency liver transplantation. The drug's multisystem toxicity was not predicted by preclinical animal studies, with grave injury to human mitochondria subsequently implicated. A concerned US Food and Drug Administration (FDA) created a task force whose findings would have a lasting impact on the agency's thinking. In 1994, the FDA proposed to amend its investigational new drug reporting requirements largely based on task force recommendations for ways to enhance the likelihood that sponsors and investigators would consider investigational agents as a possible cause of serious adverse events mimicking the underlying disease or concomitant drug toxicity. Then, in its 1997 final rule for expedited safety reporting requirements for drugs and biologics, the FDA advised sponsors that such reporting of serious, unexpected clinical trial cases would be expected when "there is a reasonable suspected causal relationship between the investigational product and the adverse event (i.e., the causal relationship cannot be ruled out)." This last clause was codified into the suspected adverse drug reaction definition in the FDA's 2003 safety reporting requirements for drugs and biologics proposed rule. The negatively received suspected adverse drug reaction and proposed causality standard were not adopted in the FDA's 2010 finalized investigational new drug safety reporting regulations, the agency stating that "'reasonable possibility' means there is evidence to suggest a

  19. Controvérsias, conveniências e críticas na implantação da TV digital no Brasil: as negociações e os estratagemas retóricos empregados pelos agentes fomentadores [doi: 10.5329/RECADM.20090801004

    Directory of Open Access Journals (Sweden)

    Roberto Bazanini

    2009-05-01

    Full Text Available Normal 0 21 false false false PT-BR X-NONE X-NONE MicrosoftInternetExplorer4 RESUMO Controvérsias, conveniências e críticas constituem a essência das discussões e disputas presentes nos atos humanos, se observados pela ótica da ciência social. Partindo-se do conceito da atividade do administrador como ciência social aplicada, o objetivo do trabalho está em investigar as polêmicas envolvidas nos estratagemas retóricos empregados pelos seis principais agentes envolvidos no processo de implantação da TV digital no Brasil e, concomitantemente, analisar e discutir os interesses de cada um desses agentes como participativos da decisão técnica/política da escolha do padrão de TV digital. Por intermédio de pesquisa exploratória de natureza qualitativa, análise pós-factum, com emprego da técnica de entrevista em profundidade embasada na metodologia proposta pela Análise Retórica, buscou-se delinear na concepção das estratégias decididas continuamente, as diferentes etapas do processo que culminaram na outorga do padrão digital da TV brasileira em 02 de dezembro de 2007. Os resultados da pesquisa apontam para a adoção do padrão japonês em perfeita consonância com os interesses dos Radiodifusores e do Governo Federal, em detrimento dos interesses do Coletivo Intervozes, da Indústria de Telecoms e da Academia, sendo que, para a Indústria de Eletro-eletrônicos não houve interferências significativas no seu modelo de negócio. Esse caso constitui um instrutivo exemplo do surgimento das controvérsias, conveniências e críticas no emprego das estratégias por parte dos executivos atuando como agentes retóricos na defesa dos interesses de suas respectivas organizações.   Palavras-Chave Estratégia, Análise Retórica; TV Digital     ABSTRACT Controversies, conveniences and critiques constitute the essence of the quarrels and disputes gifts in the acts human, if observed for the optics of social science. Breaking

  20. Trading Agents

    CERN Document Server

    Wellman, Michael

    2011-01-01

    Automated trading in electronic markets is one of the most common and consequential applications of autonomous software agents. Design of effective trading strategies requires thorough understanding of how market mechanisms operate, and appreciation of strategic issues that commonly manifest in trading scenarios. Drawing on research in auction theory and artificial intelligence, this book presents core principles of strategic reasoning that apply to market situations. The author illustrates trading strategy choices through examples of concrete market environments, such as eBay, as well as abst

  1. Relação entre a temperatura e o molhamento foliar no monocíclo da Sigatoka-negra

    Directory of Open Access Journals (Sweden)

    Cleilson do Nascimento Uchôa

    2012-06-01

    Full Text Available A influência da temperatura (21, 24, 27 e 30 °C e da duração do tempo de molhamento foliar (0, 12, 24, 48 e 72 horas na penetração do agente causal da Sigatoka-negra (Mycosphaerella fijiensis foi quantificada em ambiente controlado. A área abaixo da curva do progresso da doença (AACPD e a incidência foram influenciadas pela temperatura e pela duração do tempo de molhamento foliar. Foram constatadas diferenças significativas (P=0,05 nos valores da AACPD para as diferentes temperaturas, bem como verificada a interação significativa (P=0,05 entre temperaturas e o molhamento foliar. Em todas as temperaturas foi possível a observação de sintomas, entretanto, a maior AACPD foi observada em folhas inoculadas que permaneceram na temperatura de 24 e 27°C, a partir de 48 horas de molhamento foliar. Nas temperaturas de 21ºC e 30°C a incidência de Sigatoka-negra foi menor. O período de molhamento foliar mínimo para o progresso da doença foi de 24 horas. Não foram observados sintomas de Sigatoka-negra em folhas inoculados com o molhamento foliar de 0 hora e 12 horas em todas as temperaturas. As folhas assintomáticas, após 5 dias em câmara úmida apresentavam sintomas característicos de Sigatoka-negra, demonstrando que os conídios inoculados nas folhas permaneceram viáveis por um período na ausência de água livre na folha.

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

    Science.gov (United States)

    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 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 analyzed 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.

  3. 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.

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

    Science.gov (United States)

    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 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 analyzed 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. PMID:25505432

  5. Causality and subjectivity in discourse : The meaning and use of causal connectives in spontaneous conversation, chat interactions and written text

    NARCIS (Netherlands)

    Sanders, T.J.M.; Spooren, W.P.M.S.

    2015-01-01

    Many languages of the world have connectives to express causal relations at the discourse level. Often, language users systematically prefer one lexical item (because) over another (even highly similar) one (since) to express a causal relationship. Such choices provide a window on speakers' cognitiv

  6. Causality and subjectivity in discourse: The meaning and use of causal connectives in spontaneous conversation, chat interactions and written text

    NARCIS (Netherlands)

    Sanders, T.J.M.; Spooren, W.P.M.S.

    2015-01-01

    Many languages of the world have connectives to express causal relations at the discourse level. Often, language users systematically prefer one lexical item (because) over another (even highly similar) one (since) to express a causal relationship. Such choices provide a window on speakers’ cognitiv

  7. 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.

  8. 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

  9. Caracterización de accidentes de trabajo por caída de objetos en empresas del sector hidrocarburos

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    Gloria A. Jaramillo

    2014-12-01

    Full Text Available En una multinacional del sector de hidrocarburos prestadora de servicios de perforación y workover, que opera en las zonas de Tolima y Santander Colombia, se pudo desarrollar una investigación con el objetivo de describir la situación de accidentalidad causada por caída de objetos que se presenta en el área de taladros de perforación. La información se recolectó de los reportes de accidentes e incidentes que reposaban en la base de operaciones en Sopó entre el periodo 2010 y 2011. Al analizar los hallazgos se pudo evidenciar que son cuatro los agentes causales más significativos, dentro de los cuales están los denominados Golpes por objetos, ocupando un 68%; atrapado por o entre un objeto con 41%; caída de personas con un 30% y caída de objetos con 21 %. Este último hallazgo se deriva por la actividad propia de la perforación por la manipulación de llaves hidráulicas, objetos adicionales de acero, martillos, entre otros y su causa básica fue la falta de supervisión, liderazgo y/o planificación con 39%, seguida de procedimientos de trabajo inadecuados con el 22% y el mantenimiento inadecuado con el 11%, lo que concluye que en su mayoría son errores humanos.

  10. On Optimum Causal Cognitive Spectrum Reutilization Strategy

    CERN Document Server

    Haghighi, Kasra; Agrell, Erik

    2011-01-01

    In this paper we study opportunistic transmission strategies for cognitive radios (CR) in which causal noisy observation from a primary user(s) (PU) state is available. PU is assumed to be operating in a slotted manner, according to a two-state Markov model. The objective is to maximize utilization ratio (UR), i.e., relative number of the PU-idle slots that are used by CR, subject to interference ratio (IR), i.e., relative number of the PU-active slots that are used by CR, below a certain level. We introduce an a-posteriori LLR-based cognitive transmission strategy and show that this strategy is optimum in the sense of maximizing UR given a certain maximum allowed IR. Two methods for calculating threshold for this strategy in practical situations are presented. One of them performs well in higher SNRs but might have too large IR at low SNRs and low PU activity levels, and the other is proven to never violate the allowed IR at the price of a reduced UR. In addition, an upper-bound for the UR of any CR strategy...

  11. 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

  12. 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

  13. Solution to causality paradox upon total reflection

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang-min; CAO Zhuang-qi; ZHU Peng-fei; SHEN Qi-shun

    2006-01-01

    A dispute about the existence of an additional time (named as the Goos-H(a)nchen time) associated with the Goos-H(a)nchen shift in total reflection has recently arisen.At the same time,an inconsistency between the optical ray model and the electromagnetic theory also appears in the optical planar waveguide.By analyzing light propagation in an optical planar waveguide with both the zigzag-ray model and the electromagnetic theory,this paper shows that the Goos-H(a)nchen time really exists,and the total time delay upon total reflection upon an ideal nonabsorbing plasma mirror is the sum of the group-delay time and the Goos-H(a)nchen time.The causality paradox of total reflection of a TM wave upon an ideal nonabsorbing plasma mirror is also solved taking into consideration the negative Goos-H(a)nchen shift.Finally,the expression of the group velocity of the guided mode in optical planar waveguide was obtained,which clearly shows that the time delay upon total reflection is the sum of the group-delay time and the Goos-H(a)nchen time at given any time.

  14. Applying Causal Discovery to the Output of Climate Models - What Can We Learn from the Causal Signatures?

    Science.gov (United States)

    Ebert-Uphoff, I.; Hammerling, D.; Samarasinghe, S.; Baker, A. H.

    2015-12-01

    The framework of causal discovery provides algorithms that seek to identify potential cause-effect relationships from observational data. The output of such algorithms is a graph structure that indicates the potential causal connections between the observed variables. Originally developed for applications in the social sciences and economics, causal discovery has been used with great success in bioinformatics and, most recently, in climate science, primarily to identify interaction patterns between compound climate variables and to track pathways of interactions between different locations around the globe. Here we apply causal discovery to the output data of climate models to learn so-called causal signatures from the data that indicate interactions between the different atmospheric variables. These causal signatures can act like fingerprints for the underlying dynamics and thus serve a variety of diagnostic purposes. We study the use of the causal signatures for three applications: 1) For climate model software verification we suggest to use causal signatures as a means of detecting statistical differences between model runs, thus identifying potential errors and supplementing the Community Earth System Model Ensemble Consistency Testing (CESM-ECT) tool recently developed at NCAR for CESM verification. 2) In the context of data compression of model runs, we will test how much the causal signatures of the model outputs changes after different compression algorithms have been applied. This may result in additional means to determine which type and amount of compression is acceptable. 3) This is the first study applying causal discovery simultaneously to a large number of different atmospheric variables, and in the process of studying the resulting interaction patterns for the two aforementioned applications, we expect to gain some new insights into their relationships from this approach. We will present first results obtained for Applications 1 and 2 above.

  15. Estudo da influência das concentrações de monômero principal e de agente reticulante na estrutura do gel poli(N-isopropilacrilamida através de espectroscopia de aniquilação de pósitrons

    Directory of Open Access Journals (Sweden)

    Feijó Fernanda D.

    1999-01-01

    Full Text Available Neste trabalho, os géis termossensíveis poli(N-isopropilacrilamida - IPAA - foram caracterizados através de Espectroscopia de Vida Média de Pósitrons (EVMP e Análise Térmica como função das concentrações do monômero principal N-isopropilacrilamida e do agente reticulante N,N'-Metilenobisacrilamida. A EVMP foi usada para determinar o raio médio dos volumes livres dos géis. Os géis IPAA foram sintetizados em solução aquosa via radicais livres. Após a síntese, os géis foram cortados em cubos, lavados e secos em estufa. Depois de secos foram moídos e caracterizados através de Análise Termogravimétrica (TGA e Calorimetria Exploratória Diferencial (DSC. Os géis com composição de monômero principal e agente reticulante variando de 10x1 a 10x6, 10x1 a 16x1 e 10x1 a 16x6 mostraram um raio médio em torno de 2,8Å. O volume livre estimado para os géis não variaram com a variação da composição de monômero principal e agente reticulante. Os resultados foram interpretados em termos da estrutura desses géis.

  16. 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

  17. 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

  18. 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.

  19. Spacetime Causal Structure and Dimension from Horismotic Relation

    Directory of Open Access Journals (Sweden)

    O. C. Stoica

    2016-01-01

    Full Text Available A reflexive relation on a set can be a starting point in defining the causal structure of a spacetime in General Relativity and other relativistic theories of gravity. If we identify this relation as the relation between lightlike separated events (the horismos relation, we can construct in a natural way the entire causal structure: causal and chronological relations, causal curves, and a topology. By imposing a simple additional condition, the structure gains a definite number of dimensions. This construction works with both continuous and discrete spacetimes. The dimensionality is obtained also in the discrete case, so this approach can be suited to prove the fundamental conjecture of causal sets. Other simple conditions lead to a differentiable manifold with a conformal structure (the metric up to a scaling factor as in Lorentzian manifolds. This structure provides a simple and general reconstruction of the spacetime in relativistic theories of gravity, which normally requires topological structure, differential structure, and geometric structure (which decomposes in the conformal structure, giving the causal relations and the volume element. Motivations for such a reconstruction come from relativistic theories of gravity, where the conformal structure is important, from the problem of singularities, and from Quantum Gravity, where various discretization methods are pursued, particularly in the causal sets approach.

  20. 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.