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Sample records for biliar principal antes

  1. Repercussões temporais da ligadura do ducto biliar principal em ratos Wistar

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    Maia Eugenio Lincoln Campos

    2003-01-01

    Full Text Available OBJETIVO: Objetivou-se investigar os efeitos temporais da ligadura do ducto biliar principal, em ratos Wistar. MÉTODOS: Utilizaram-se 48 ratos machos distribuídos em 2 grupos e redistribuídos em 4 subgrupos (n=06, identificados pelo tempo estipulado para a coleta das amostras (12, 24, 48 e 168 horas. Após laparotomia, os animais foram submetidos à dissecção e passagem de dois fios circundando o ducto biliar principal, sem ligadura (Grupo 1 e com ligadura (Grupo 2. RESULTADOS: As concentrações das bilirrubinas séricas (total, direte e indireta quando comparadas ao repectivo grupo controle, aumentaram (p<0,05 nos animais do grupo 2, nos tempos 24, 48 e 168 horas. As concentrações de proteína C reativa e fosfatase alcalina aumentaram (p<0,05 no grupo 2 no tempo 24 horas e nos tempos 24 e 48 horas, respectivamente. Concentrações de albumina e gamaglutamil transferase, não apresentaram diferenças significantes nos dois grupos. Foram observadas, no exame histopatológico, hiperplasia ductal, pericolangite e colangite no grupo 2 e pericolangite no grupo 1. CONCLUSÕES: A ligadura do ducto biliar principal induz aumento das concentrações séricas de bilirrubinas, proteína C reativa e fosfatase alcalina. Hiperplasia ductal, pericolangite e colangite são as principais alterações histológicas encontradas nos fígados dos ratos submetidos à ligadura do ducto biliar principal.

  2. Atresia biliar: una enfermedad grave

    OpenAIRE

    Ramonet, Margarita; Ciocca, Mirta; Alvarez, Fernando

    2014-01-01

    La atresia biliar es una grave enfermedad que se manifiesta en los recién nacidos, y se desconoce su causa. La inflamación y destrucciónprogresiva de los conductos biliares conducen a la aparición de ictericia, coluria y acolia entre la segunda y sexta semana de vida. Como existen múltiples causas de colestasis neonatal en esta etapa de la vida, es necesario realizar un diagnóstico y derivación precoz para ofrecer un tratamiento quirúrgico, con el fin de restablecer el flujo biliar. Alrededor...

  3. Atresia das vias biliares extra-hepáticas: conhecimentos atuais e perspectivas futuras

    OpenAIRE

    Carvalho,Elisa de; Ivantes,Cláudia Alexandra Pontes; Bezerra,Jorge A.

    2007-01-01

    OBJETIVOS: Apresentar uma revisão atualizada sobre atresia das vias biliares extra-hepáticas, com ênfase em etiopatogenia, abordagens diagnósticas e terapêuticas e prognóstico. FONTES DOS DADOS: Foram selecionadas pelos sites de busca médica (MEDLINE e PubMed) pesquisas relacionadas à atresia biliar, utilizando as seguintes palavras-chave: biliary atresia,etiopathogenesis, diagnosis, treatment, prognosis, children. SÍNTESE DOS DADOS A atresia das vias biliares extra-hepáticas é a principal in...

  4. Microcristais biliares na pancreatite aguda idiopática: indício para etiologia biliar oculta subjacente

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    CHEBLI Júlio Maria Fonseca

    2000-01-01

    ultra-sonográfico durante o seguimento não revelou cálculo biliar em nenhum destes. Concluiu-se que a detecção de microcristais biliares na pancreatite aguda idiopática sugeriu etiologia biliar oculta subjacente. Adicionalmente, intervenção terapêutica específica nos pacientes com pancreatite aguda idiopática recurrente e microcristais reduziu as recidivas durante o seguimento. Finalmente, pancreatite aguda (particularmente, recurrente não deveria ser rotulada como idiopática antes da análise microscópica da bile visando a detecção ou exclusão da presença de microcristais.

  5. ANT

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    van der Duim, René; Ren, Carina Bregnholm; Jóhannesson, Gunnar Thór

    2017-01-01

    Ten years ago actor-network theory (ANT) entered this journal. To illustrate how the relational ontology and sensibilities of ANT lend themselves to particular kinds of research, we first interrogate the main controversies as a way to open up and discuss the main premises of ANT. These debates...... concern the status and agency of objects and non-humans, ANT’s denial of the explanatory power of social structures, and the political implications of ANT. Second we present ANT’s relevance for tourism studies and discuss what ANT ‘does’ in practice. After summarizing a decade of relations between ANT...... and tourism, we conclude by tracing three future trajectories of how we have ‘moved away with’ ANT into new areas of discovery....

  6. Atresia biliar extra-hepática: métodos diagnósticos

    OpenAIRE

    Cauduro Sydney M.

    2003-01-01

    OBJETIVO: enfatizar a importância do diagnóstico precoce da atresia biliar extra-hepática e sua relação direta com o restabelecimento cirúrgico do fluxo biliar antes do segundo mês de vida, discutindo os diversos métodos complementares utilizados, objetivando selecionar os de maior evidência, evitando retardo diagnóstico e, conseqüentemente, piora do prognóstico. MÉTODO: pesquisa bibliográfica referente ao período de 1985 a 2001, no Medline e MdConsult, através das palavras-chaves: colestase ...

  7. Tumores de los conductos biliares

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    Santiago Triana Cortés

    1955-02-01

    Los tumores benignos de los conductos biliares son relativamente raros. Christopher, que ha revisado recientemente este asunto, sólo pudo encontrar cuarenta y un casos publicados. Los papilomas parecen los más frecuentes, pero se les encuentra con menor frecuencia en los conductos que en la vesícula. Los adenomas son también tumores benignos de los más frecuentes en los conductos; en general, son múltiples y quísticos, y en algunos casos parecen derivar del epitelio de los conductos.

  8. Atresia das vias biliares extra-hepáticas: conhecimentos atuais e perspectivas futuras Extrahepatic biliary atresia: current concepts and future directions

    OpenAIRE

    Elisa de Carvalho; Cláudia Alexandra Pontes Ivantes; Jorge A. Bezerra

    2007-01-01

    OBJETIVOS: Apresentar uma revisão atualizada sobre atresia das vias biliares extra-hepáticas, com ênfase em etiopatogenia, abordagens diagnósticas e terapêuticas e prognóstico. FONTES DOS DADOS: Foram selecionadas pelos sites de busca médica (MEDLINE e PubMed) pesquisas relacionadas à atresia biliar, utilizando as seguintes palavras-chave: biliary atresia,etiopathogenesis, diagnosis, treatment, prognosis, children. SÍNTESE DOS DADOS A atresia das vias biliares extra-hepáticas é a principal in...

  9. Prevalência e fisiopatologia da litíase biliar em pacientes submetidos a transplante de órgãos Prevalence and physiopathology of gallstone in transplant patients

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    Júlio Cesar Uili Coelho

    2009-06-01

    Full Text Available INTRODUÇÃO: O objetivo do presente estudo é apresentar revisão da prevalência e dos principais mecanismos fisiopatológicos que levam a formação da litíase biliar em pacientes submetidos a transplante de órgãos. MÉTODOS: Revisão da literatura abrangendo 29 publicações obtidas das bases Medline/Pubmed, Scielo e Lilacs com cruzamento dos unitermos "transplante, transplante renal, transplante hepático, cálculo biliar, colecistite.". Vários estudos que utilizaram a ultrassonografia demonstraram aumento na prevalência da litíase biliar em pacientes submetidos a transplante de órgãos. A taxa de formação de cálculos novos após o transplante variou de 10 a 55% e a total (cálculos formados antes e após o transplante de 17 a 68%. Tanto o ganho como a perda de peso rápida, que podem ocorrer após o transplante, predispõem à formação de cálculos biliares. O uso do imunossupressor ciclosporina é considerado como o principal fator que aumenta a incidência de litíase biliar após o transplante. CONCLUSÃO: A prevalência de litíase biliar é maior nos pacientes submetidos a transplante de órgãos do que na população geral. As principais alterações que ocorrem no paciente transplantado que predispõem a formação dos cálculos são as alterações do peso corporal, uso de imunossupressores, diabete melito e hiperlipidemia.INTRODUCTION: The objective of the present study is to review the prevalence and the main physiopathologic mechanisms that result in gallstone formation in transplant patients. METHODS: Literature review with 29 papers included in Medline/Pubmed, Scielo and Lilacs database, crossing key-words "transplantation; kidney transplantation; liver transplantation; gallstone; cholecystitis". Several ultrasonographic studies have demonstrated an increase in gallstone prevalence in transplant patients. The formation rate of new stones after transplantation varied from 10 to 55% and the rate of total stones

  10. Retirada de fasciola hepatica da via biliar principal por coledocoscopia

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    Coral, Roberto Pelegrini; Mastalir, Eduardo T.; Mastalir, Fabiane Pinto

    2007-01-01

    The authors present a rare case of hepatic fascioliasis in a female patient 53-years-old, coming from the rural zone of Rio Grande do Sul, a southern State from Brazil. She has presented with biliary colic, fluctuant jaundice and eosinophilia. Abdominal ultrasound has shown a dilated biliary tree with inside heterogeneous images. At surgery we have found inside the biliary tree several Fasciola hepatica, which have been pulled out with the choledocoscope. We have proceeded with biliodigestive...

  11. Retirada de fasciola hepatica da via biliar principal por coledocoscopia

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    Roberto Pelegrini Coral

    Full Text Available The authors present a rare case of hepatic fascioliasis in a female patient 53-years-old, coming from the rural zone of Rio Grande do Sul, a southern State from Brazil. She has presented with biliary colic, fluctuant jaundice and eosinophilia. Abdominal ultrasound has shown a dilated biliary tree with inside heterogeneous images. At surgery we have found inside the biliary tree several Fasciola hepatica, which have been pulled out with the choledocoscope. We have proceeded with biliodigestive anastomosis using the small intestine. The patient remains asymptomatic six months after surgical procedure. Small intestine. The patient remains asymptomatic six months after surgical procedure.

  12. Atresia biliar: a experiência Brasileira

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    Elisa de Carvalho

    2010-12-01

    Full Text Available OBJETIVO: Avaliar as características epidemiológicas, clínicas e prognósticas de crianças com atresia biliar. MÉTODOS: Dados sobre portoenterostomia, transplante hepático (TxH, idade no último seguimento e sobrevida foram coletados dos prontuários de pacientes acompanhados em seis centros no Brasil (1982-2008 e comparados em relação às décadas do procedimento cirúrgico. RESULTADOS: Dos 513 pacientes, 76,4% foram submetidos a portoenterostomia [idade: 60,0-94,7 (82,6±32,8 dias] e 46,6% foram submetidos a TxH. Em 69% dos casos, o TxH foi realizado após a portoenterostomia, enquanto em 31% dos casos o TxH foi realizado como cirurgia primária. Os pacientes da região Nordeste foram submetidos a portoenterostomia mais tardiamente do que as crianças das regiões Sul (p = 0,008 e Sudeste (p = 0,0012, embora, mesmo nas duas últimas regiões, a idade no momento da portoenterostomia tenha sido superior ao desejável. Ao longo das décadas, houve aumento progressivo do número de TxH realizados. A sobrevida global foi de 67,6%. A sobrevida aumentou nas últimas décadas (anos 1980 versus 1990, p = 0,002; anos 1980 versus 2000, p 90 dias, respectivamente. Os pacientes transplantados apresentaram taxas de sobrevida mais elevadas (88,3%. A sobrevida de 4 anos com fígado nativo foi de 36,8%, inversamente correlacionada à idade no momento da portoenterostomia (54, 33,3, 26,6% para 90 dias, respectivamente. CONCLUSÕES: Este estudo multicêntrico demonstrou que o encaminhamento tardio das crianças portadoras de atresia biliar ainda é um problema no Brasil, influenciando a sobrevida destes pacientes. Estratégias que proporcionam o encaminhamento precoce estão sendo desenvolvidas com o objetivo de reduzir a necessidade de transplante hepático nos primeiros anos de vida.

  13. Formación de cálculos biliares de colesterol: Nuevos avances científicos

    OpenAIRE

    Castro-Torres, Ibrahim G

    2012-01-01

    La investigación científica sobre la formación de cálculos biliares de colesterol, ha comprobado la participación de numerosos genes, entre los cuales se encuentran receptores nucleares y transportadores biliares. El desequilibrio fisicoquímico entre los lípidos biliares más importantes produce hipersecreción de colesterol en la bilis, una etapa necesaria para sobresaturar la vesícula biliar. Las sales biliares son insuficientes para solubilizar al colesterol en micelas mixtas, por lo que est...

  14. Atresia das vias biliares extra-hepáticas: conhecimentos atuais e perspectivas futuras Extrahepatic biliary atresia: current concepts and future directions

    Directory of Open Access Journals (Sweden)

    Elisa de Carvalho

    2007-04-01

    Full Text Available OBJETIVOS: Apresentar uma revisão atualizada sobre atresia das vias biliares extra-hepáticas, com ênfase em etiopatogenia, abordagens diagnósticas e terapêuticas e prognóstico. FONTES DOS DADOS: Foram selecionadas pelos sites de busca médica (MEDLINE e PubMed pesquisas relacionadas à atresia biliar, utilizando as seguintes palavras-chave: biliary atresia,etiopathogenesis, diagnosis, treatment, prognosis, children. SÍNTESE DOS DADOS A atresia das vias biliares extra-hepáticas é a principal indicação de transplante hepático na faixa etária pediátrica. Quanto à etiologia, o citomegalovírus, o reovírus e o rotavírus têm sido os agentes mais estudados como possíveis desencadeadores da obstrução imunomediada da árvore biliar. A resposta imune, especialmente o predomínio da resposta TH1 e do interferon gama, a susceptibilidade genética e as alterações do desenvolvimento embrionário da árvore biliar são aspectos que podem participar na etiopatogênese da obliteração das vias biliares extra-hepáticas. Ainda hoje, o único tratamento disponível é a portoenterostomia, cujos resultados são melhores quando realizada nos primeiros 2 meses de vida. Em relação ao prognóstico, as crianças não tratadas vão a óbito na totalidade, por complicações relacionadas à hipertensão portal e à cirrose hepática, e mesmo os casos tratados necessitam, em sua maioria, do transplante hepático. CONCLUSÃO: A atresia das vias biliares extra-hepáticas continua sendo a principal indicação de transplante hepático em crianças, e a mudança deste panorama depende de um melhor entendimento da etiopatogenia da obstrução biliar nos diferentes fenótipos da doença. Investigações futuras a respeito do papel do interferon gama e de outras citocinas são necessárias para avaliar se esses aspectos seriam potenciais alvos de intervenção terapêutica.OBJECTIVE: To provide an updated review on extrahepatic biliary atresia, focusing

  15. Lesiones iatrogénicas de las vías biliares

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    Limaylla-Vega, Himerón; Vega-Gonzales, Emilio

    2017-01-01

    Las lesiones iatrogénicas de las vías biliares (LIVB) representan una complicación quirúrgica grave de la colecistectomía laparoscópica (CL). Ocurre frecuentemente cuando se confunde el conducto biliar con el conducto cístico; y han sido clasificados por Strasberg y Bismuth, según el grado y nivel de la lesión. Alrededor del tercio de las LIVB se reconocen durante la CL, al detectar fuga biliar. No es recomendable su reparación inmediata, especialmente cuando la lesión está próxima a la confl...

  16. Morbilidad y mortalidad por afecciones benignas del sistema biliar: Nuestra experiencia

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    Jorge Reyes Cardero

    1997-04-01

    Full Text Available Se realizó un estudio descriptivo y prospectivo sobre morbilidad y mortalidad por enfermedades benignas del sistema biliar en 4 266 pacientes operados en el Hospital Provincial Clinicoquirúrgico Docente "Saturnino Lora" de Santiago de Cuba, en el que se precisó la incidencia de diferentes variables. Las enfermedades más frecuentes fueron las colecistitis y colecistosis, en pacientes del sexo femenino, y un número importante de operados superaba los 60 años. Las complicaciones más comúnmente halladas en el período preoperatorio fueron: la litiasis coledociana y la pancreatitis aguda; en el peroperatorio: sobre la vesícula, la vía biliar y el hígado y en el posoperatorio inmediato las inespecíficas, que prevalecieron sobre las específicas. La mortalidad se consideró dentro de límites aceptables, y como causa fundamental de muerte en los ancianos se destaca el síndrome de disfunción múltiple de órganosA descriptive and prospective study on morbidity and mortality of bening diseases of the biliary tract was performed on 4 266 patients operated on at "Saturnino Lora" Provincial Teaching hospital, Santiago de Cuba with the aim of assessing the incidence of different variables. The most frequent diseases were found to be cholecystitis and cholecystosis in female patients, and a great number of surgically treated patients were over 60 years of age. The most frequently complications found within the preoperative period were: cholelithiasis and acute pancreatitis; during the perioperative period the most common were the complications of the gall bladder, the bile duct, and the liver, and during the immediate portoperative period the most frequent complications were found to be nonspecific which prevailed over the specific ones. Mortality rate was considered to be within acceptable limits, and the syndrome of multiple organ failure was found to be the principal cause of death among aged patients

  17. El íleo biliar: una revisión de la literatura médica

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    C.F. Ploneda-Valencia

    2017-07-01

    Conclusiones: El objetivo del tratamiento del íleo biliar es liberar la obstrucción, obtenido a través de la enterolitotomía. Esta es la técnica recomendada para el manejo del íleo biliar debido a su morbimortalidad menor, comparada con las otras técnicas.

  18. EFEITO DE CÁLCULOS BILIARES HUMANOS NA CAVIDADE PERITONEAL DE RATOS

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    Torres, Orlando Jorge Martins; Valadão, José Aparecido; Silva, Ailton José Rodrigues; Macau, Rosane Penha; Cintra, Jean Carlos Antunes; Dietz, Ulrich Andreas; Nassif, Paulo Afonso Nunes

    1998-01-01

    Este estudo tem por objetivo analisar experimentalmente as características macroscópicas e microscópicas de cálculos biliares humanos na cavidade peritoneal de ratos. Foram utilizados 32 ratos Wistar, machos, pesando entre 205 e 268 g. Estes animais foram distribuídos em dois grupos e o procedimento cirúrgico foi realizado em cada grupo: no grupo A (n =16), os animais foram submetidos a manipulação intestinal; no grupo B (n=16), cálculos biliares humanos foram colocados na cavidade peritoneal...

  19. Tratamento cirúrgico postergado da pancreatite aguda biliar

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    Rodrigo Altenfelder Silva

    Full Text Available A análise do tratamento cirúrgico de doentes portadores de pancreatite biliar mostra a existência de controvérsias em relação à oportunidade da intervenção, principalmente se deve ser precoce ou postergada. Do mesmo modo, a possibilidade do emprego de procedimentos endoscópicos no pré, intra ou pós-operatório e o advento da videolaparoscopia, trouxeram novos aspectos à discussão. Não existe consenso sobre a escolha da melhor conduta. Em função disso, analisamos retrospectivamente os resultados imediatos de 107 doentes portadores de forma leve de pancreatite, todos com menos de três sinais de gravidade, segundo o critério de estratificação proposto por Ranson, e que foram submetidos ao tratamento cirúrgico postergado na mesma internação, no período de janeiro de 1988 a maio de 1999, tanto por via convencional como por via laparoscópica. Desses, 80 doentes (75% eram do sexo feminino, 90% da raça branca e a média de idade foi de 46 anos. Os doentes foram operados em média após 9,5 dias de internação e receberam alta hospitalar após 2,9 dias, o que resultou numa permanência hospitalar média de 12,6 dias. A colangiografia intra-operatória foi realizada em 102 casos (96% e a colangiografia endoscópica pré-operatória em 24 doentes (22,4%. Os resultados mostraram incidência de coledocolitíase em 25 casos (23%, taxa de morbidade de 12% e mortalidade nula. Dos 107 casos estudados, 64 (60% foram operados pela via de acesso convencional e 43 (40% pela via laparoscópica. A comparação dos resultados entre as vias de acesso empregadas mostrou diferença estatística significante em relação ao intervalo de tempo pós-operatório, que foi menor nos doentes submetidos à via de acesso laparoscópica. Concluímos, assim, que o tratamento cirúrgico postergado de doentes portadores de pancreatite biliar na forma leve apresenta baixas morbidade e mortalidade e pode ser feito tanto pela via convencional como pela via

  20. Atresia biliar extra-hepática: métodos diagnósticos Extrahepatic biliary atresia: diagnostic methods

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    Sydney M. Cauduro

    2003-04-01

    Full Text Available OBJETIVO: enfatizar a importância do diagnóstico precoce da atresia biliar extra-hepática e sua relação direta com o restabelecimento cirúrgico do fluxo biliar antes do segundo mês de vida, discutindo os diversos métodos complementares utilizados, objetivando selecionar os de maior evidência, evitando retardo diagnóstico e, conseqüentemente, piora do prognóstico. MÉTODO: pesquisa bibliográfica referente ao período de 1985 a 2001, no Medline e MdConsult, através das palavras-chaves: colestase neonatal, atresia biliar extra-hepática e hepatite neonatal. Também foram selecionados artigos nacionais e estrangeiros a partir da bibliografia das publicações consultadas e, quando necessário, para melhor entendimento do tema, opiniões emitidas em teses e livros-textos foram referidas. RESULTADOS: a revisão da bibliografia consultada permite afirmar que o diagnóstico precoce das AVBEH e tratamento cirúrgico para restabelecer o fluxo biliar até 60 dias de vida são fundamentais na obtenção de bons resultados. Entre os diversos métodos complementares de diagnóstico, a colangiografia por RM, US e a biópsia hepática são os que proporcionam os maiores índices de acerto. CONCLUSÕES: o encaminhamento de pacientes portadores de AVBEH para centros de referências no Brasil ainda é efetuado tardiamente, provavelmente pela falta de esclarecimento dos médicos de atenção primária, aliada às dificuldades burocráticas e tecnológicas. A experiência da Inglaterra em relação ao programa "Alerta Amarelo", permitiu que o número de crianças encaminhadas para tratamento cirúrgico antes dos 60 dias de vida aumentasse significativamente. Entre os métodos complementares, a colangiografia por RM, a US e a biópsia hepática deverão ser utilizados, dependendo dos recursos tecnológicos das unidades de diagnóstico.OBJECTIVE: to emphasize the importance of precocious diagnosis of extrahepatic biliary atresia and its direct

  1. Importancia de la excreción biliar en la farmacocinética del paracetamol en la rata

    OpenAIRE

    Schaiquevich, Paula S.; Niselman, Ada Viviana; Rubio, Modesto Carlos

    2006-01-01

    El presente trabajo reporta el estudio de la farmacocinética del paracetamol en ratas (100 mg/kg, p.o) con flujo biliar modificado, interrumpido por canulación del conducto biliar o estimulado por acción farmacológica con ácido ursodesoxicólico. A pesar de que el paracetamol sufre recirculación enterohepática y que la excreción biliar de la droga es una vía importante de eliminación en la rata, la alteración del flujo biliar no provocó diferencias estadísticamente significativas en el tiempo ...

  2. Características ultrassonográficas de fígado, vesícula biliar, rins, vesícula urinária e jejuno em coelhos jovens e adultos

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    Kassy G. da Silva

    Full Text Available RESUMO: O presente trabalho descreveu características e comparou mensurações do fígado, vesícula biliar, rins, vesícula urinária e jejuno de coelhos da raça Nova Zelândia Branco (NZB jovens e adultos. O grupo dos jovens foi composto por 39 coelhos de ambos os sexos (20 machos e 19 fêmeas, desmamados aos 30-31 dias de idade, sendo as avaliações realizadas aos 35, 56 e 77 dias de idade. O grupo dos adultos foi composto por 23 fêmeas e 15 machos, com idade superior a 6 meses, sendo realizada uma avaliação ultrassonográfica por animal. O exame consistiu na avaliação do fígado, vesícula biliar, rins direito e esquerdo, jejuno e vesícula urinária. Todos os animais foram pesados antes dos exames. O peso médio dos animais aumentou (p0,05 da espessura das camadas do jejuno entre as idades, apresentando média de 0,23 cm para todos os animais. Estes são os primeiros dados brasileiros de características ultrassonográficas de fígado, vesícula biliar, rins, jejuno e vesícula urinária para coelhos NZB de 35, 56 e 77 dias de vida e adultos.

  3. Avaliação química e termoanalítica de cálculos biliares e bile vesicular humana de pacientes do sexo masculino

    OpenAIRE

    Cláudia Mônica Tortorelli

    2006-01-01

    Este trabalho teve como meta principal ampliar o estudo anteriormente relatado por Mercuri em 2000, agora com a caracterização química e termoanalítica de cálculos biliares e as biles vesiculares humanas, especificamente, de pacientes do sexo masculino. Para ambos os tipos de caracterização foram utilizadas várias técnicas, como: (a) Análise Elementar (AE), para determinação de teores de C, H e N. (b) Espectroscopia no infravermelho com transformada de Fourier (FTIR), com o objetivo de verifi...

  4. Beyond ANT

    DEFF Research Database (Denmark)

    Jansen, Till

    2017-01-01

    Actor-Network-Theory (ANT) offers an ‘infra-language’ of the social that allows one to trace social relations very dynamically, while at the same time dissolving human agency, thus providing a flat and de-centred way into sociology. However, ANT struggles with its theoretical design that may lead...... us to reduce agency to causation and to conceptualize actor-networks as homogeneous ontologies of force. This article proposes to regard ANT’s inability to conceptualize reflexivity and the interrelatedness of different ontologies as the fundamental problem of the theory. Drawing on Günther......, it offers an ‘infra-language’ of reflexive relations while maintaining ANT’s de-centred approach. This would enable us to conceptualize actor-networks as non-homogeneous, dynamic and connecting different societal rationales while maintaining the main strengths of ANT....

  5. Ictericia obstructiva secundaria a migración de fragmentos de hepatocarcinoma a la vía biliar

    OpenAIRE

    HEPP K,JUAN; BALBONTÍN M,PAULINA; ARMAS M,RODOLFO; NAVARRETE G,CLAUDIO; RÍOS R,HORACIO; HUMERES A,ROBERTO; RODRÍGUEZ M,GABRIELA; ROA E,IVÁN

    2010-01-01

    La ictericia obstructiva es una presentación poco común en un hepatocarcinoma (HC). Cuando en estos casos existe ictericia, habitualmente se debe a daño progresivo por cirrosis, o a infiltración tumoral extensa. El crecimiento o vaciamiento tumoral hacia la vía biliar se ha descrito ocasionalmente como causa de ictericia obstructiva. En raras ocasiones, puede tratarse de fragmentos de hepatocarcinoma que migran hacia la vía biliar, obstruyéndola. Presentamos un caso de ictericia obstructiva p...

  6. Primary biliary cirrhosis and myopathy: an uncommon association Cirrose biliar primária e miopatia: uma rara associação

    Directory of Open Access Journals (Sweden)

    Bruno Cupertino Migueletto

    1999-10-01

    Full Text Available Primary biliary cirrhosis (PBC is a cholestatic liver disease, which is characterized by a chronic inflammatory destruction of intrahepatic bile ducts. It is a rare disorder whose precise etiology is still to be elucidated. Even though the liver is the principal target of PBC, other organ systems also might be affected. Muscular involvement has rarely been described in this disease, and in the majority of cases, muscular weakness has been interpreted as polymyositis. We report the case of a 48-year-old woman suffering from classic PBC, in association with a myopathy whose histological features are distinct from the cases reported before. We also performed a MEDLINE research for PBC and concomitant muscular diseases.A cirrose biliar primária (CBP é uma doença hepática colestática crônica de etiologia desconhecida e rara. Apesar do principal órgão acometido na CBP ser o fígado, outros órgãos podem também ser afetados. O acometimento muscular raramente tem sido relatado em pacientes com CBP e na maioria destes casos, a fraqueza muscular tem sido interpretada como Polimiosite. Nós relatamos o caso de uma mulher de 48 anos com CBP e miopatia com achados histopatológicos distintos dos casos anteriormente descritos e fizemos uma revisão da literatura sobre o acometimento muscular na CBP.

  7. Representaciones humorísticas en el principal diario argentino ante el "resurgimiento" sindical Humorous representation in Argentina´s leading newspaper in view of the "resurgence" of the union actor

    Directory of Open Access Journals (Sweden)

    Vanesa Coscia

    2012-06-01

    Full Text Available En este artículo nos proponemos analizar el funcionamiento del humor gráfico cuando se lo incluye en las coberturas periodísticas que abordan los temas de conflictividad sindical en el período 2004-2007. Esta época, bajo el gobierno de Néstor Kirchner, coincidió con un "resurgimiento" del actor sindical en la escena política nacional, a partir de la dinamización de la negociación colectiva, aumento de puestos laborales, incremento de luchas por aumentos salariales y acuerdos tripartitos entre las principales organizaciones sindicales y empresariales. El estudio se concentra en el caso de Clarín, teniendo en cuenta el lugar de privilegio que, en tanto actor político y económico, tiene este medio en la escena nacional. Este diario forma parte y se constituye en piedra angular del holding empresarial de nombre homónimo Grupo Clarin, principal grupo multimedial nacional con control de diarios y revistas, licencias de televisión, Internet, emisoras radiales y productoras, entre otras. La idea de analizar las representaciones mediáticas sobre la temática sindical focalizando, en este caso, en el funcionamiento del humor (análisis de chistes y caricaturas surge de la sospecha de que el humor gráfico político funciona, como señala Mazzei (1997:88 como un recurso ante el cual "el receptor relaja su guardia y acepta -risueñamente- muchas de las premisas implícitas en el mensaje de la nota". La pregunta que guía este estudio es, entonces, cómo el humor funciona modalizando o potenciando las narrativas mediáticas, construyendo y fortaleciendo ciertas nociones del sentido común en torno a cuestiones históricas del sindicalismo nacional.The aim of the following article is to analyse the purpose of graphic humour when used in political journalism for the coverage of conflicts related to trade unions in the period 2004-2007. During Kirchner's government trade unions became a central political and social actor favoured by collective

  8. Fire Ant Bites

    Science.gov (United States)

    ... Favorite Name: Category: Share: Yes No, Keep Private Fire Ant Bites Share | Fire ants are aggressive, venomous insects that have pinching ... across the United States, even into Puerto Rico. Fire ant stings usually occur on the feet or ...

  9. Perfuração espontânea da via biliar principal na infância

    Directory of Open Access Journals (Sweden)

    Pedro J. A. Aratanha

    Full Text Available The authors report a case of spontaneous perforation of the biliary tract (S.P.B.T in a three-month-old infant. The diagnosis was suspected before the operation by clinical signs and diagnostic tests. The importance of paracentesis and scintigraphy is stressed. A surgical approach was chosen and drainage procedure of the area around the perforation and a cholecystostomy were done. S.P.B.T. is rare and its etiology is controversial, but cannot be forgotten in association between biliary ascites and cholestatic jaundice during the first months of life.

  10. Calidad de vida de pacientes con obstrucción maligna del esófago, la vía biliar y la vía urinaria sometidos a intervencionismo radiológico paliativo Informe preliminar Medellín, Colombia

    Directory of Open Access Journals (Sweden)

    Jorge Guzmán Tatis

    2005-02-01

    Full Text Available En el momento de hacer el diagnóstico de los tumores malignos que ocasionan obstrucción del esófago, la vía biliar y el tracto urinario, la mayoría de los pacientes no tiene otras opciones terapéuticas excepto los cuidados paliativos. La presencia de síntomas molestos e incapacitantes, así como la amenaza a la existencia y el miedo a la muerte comprometen la calidad de vida. En este trabajo se realizaron a 25 pacientes procedimientos intervencionistas radiológicos como fueron: prótesis metálicas autoexpandibles en el esófago y en la vía biliar y nefrostomía percutánea. Se evaluaron, antes del procedimiento y a los 1, 3 y 6 meses la evolución de los síntomas clínicos, los criterios paraclínicos, las complicaciones de los procedimientos, el dolor por medio de la escala análoga visual y la calidad de vida por medio del cuestionario SF36. En los 8 pacientes con cáncer del esófago mejoraron el dolor y la disfagia y se mantuvieron el índice de masa corporal y la calidad de vida. En los 11 con obstrucción urinaria mejoraron el nitrógeno ureico, la creatinina y la calidad de vida al primer mes y al tercero. En los 6 que tenían obstrucción maligna de la vía biliar mejoraron los niveles de bilirrubina, el prurito, las náuseas y la calidad de vida al mes, con estabilidad del estado nutricional.

  11. Graveyards on the Move: The Spatio-Temporal Distribution of Dead Ophiocordyceps-Infected Ants

    DEFF Research Database (Denmark)

    Pontoppidan, Maj-Britt; Himaman, Winanda; Hywel-Jones, Nigel L.

    2009-01-01

    rainforest. We established that high density aggregations exist (up to 26 dead ants/m2), which we coined graveyards. We further established that graveyards are patchily distributed in a landscape with no or very few O. unilateralis-killed ants. At some, but not all, spatial scales of analysis the density...... unilateralis, which is pan-tropical in distribution, causes infected worker ants to leave their nest and die under leaves in the understory of tropical rainforests. Working in a forest dynamic plot in Southern Thailand we mapped the occurrence of these dead ants by examining every leaf in 1,360 m2 of primary...... of dead ants correlated with temperature, humidity and vegetation cover. Remarkably, having found 2243 dead ants inside graveyards we only found 2 live ants of the principal host, ant Camponotus leonardi, suggesting that foraging host ants actively avoid graveyards. We discovered that the principal host...

  12. Tratamento cirúrgico da atresia de vias biliares: a experiência do hospital municipal jesus, 1997-2000

    Directory of Open Access Journals (Sweden)

    Lisieux Eyer de Jesus

    Full Text Available OBJETIVO: Analisar a indicação, resultados e limitações da portoenterostomia para o tratamento da atresia de vias biliares em hospital infantil terciário no Rio de Janeiro-RJ/Brasil. MÉTODO: Foram estudados prospectivamente oito pacientes submetidos à portoenterostomia do tipo Kasai 1, num período de três anos (1997-2000. Todos foram submetidos à antibioticoterapia profilática, uso de colerético, reavaliação médica mensal nos primeiros seis meses de seguimento e reavaliação laboratorial, ultra-sonográfica e através de endoscopia digestiva alta em prazos programados. RESULTADOS: Em cinco pacientes foi possível obter drenagem biliar estável e satisfatória por > 6 meses pós-operatórios. Quatro faleceram no período de observação (um por insuficiência hepática, um por colangite, dois por hemorragias digestivas, inclusive os três pacientes em que não foi obtida drenagem biliar satisfatória. Quatro persistem em bom estado geral, anictéricos, um deles com fibrose hepática residual grave e provável indicação futura de transplante hepático. Detectamos problemas graves com relação ao encaminhamento tardio de doentes para tratamento e para disponibilizar transplante hepático quando necessário. CONCLUSÕES: Os resultados da portoenterostomia são compensadores quando é possível obter bom débito biliar no pós-operatório. Em pacientes em que não é obtida boa drenagem biliar o pós-operatório é tormentoso e o óbito é esperado até o segundo ano de vida sem o uso de transplante hepático. É necessário disponibilizar transplante hepático pediátrico em nosso meio e conscientizar a comunidade médica para o encaminhamento precoce de bebês ictéricos além dos primeiros 15 dias de vida para investigação e tratamento em unidades especializadas.

  13. Primeras experiencias con drenaje biliar percutáneo de urgencia en la colangitis aguda

    Directory of Open Access Journals (Sweden)

    José Luis González González

    Full Text Available Introducción: la obstrucción biliar es motivo frecuente de morbilidad en los pacientes con metástasis hepáticas, adenopatías periportales y cáncer hepatobiliopancreático. La colangitis aguda es la complicación más temida, debido a su mortalidad. En este trabajo se presentan los primeros abordajes percutáneos realizados por cirujanos del Hospital Clínicoquirúrgico "Hermanos Ameijeiras" como herramienta para el tratamiento urgente de esta entidad. Objetivo: caracterizar el drenaje percutáneo transparietohepático de urgencia en pacientes con colangitis aguda e ictericia obstructiva. Métodos: se realizó un estudio descriptivo, prospectivo y aplicado con 30 pacientes atendidos de esta forma en dicha institución entre enero de 2008 y diciembre de 2010. Resultados: el diagnóstico etiológico preponderante fue el de tumor maligno de la cabeza del páncreas. La localización baja de la lesión duplicó a la localización alta. La mejoría clínica de la ictericia se evidenció en la mayoría de los pacientes después de una semana tras el procedimiento: el drenaje percutáneo constituyó el método definitivo en el 73,3 % de los pacientes. Las edades medias para los distintos diagnósticos etiológicos exhibieron diferencias estadísticamente significativas. No hubo complicaciones ni mortalidad relacionadas con el procedimiento. Conclusiones: el drenaje biliar percutáneo guiado por ultrasonido es una herramienta útil y segura para el tratamiento de urgencia de la colangitis aguda. Es un método que pueden realizar los cirujanos generales con entrenamiento adecuado y específico, y tiene asociadas pocas complicaciones.

  14. Fatores preditivos de coledocolitíase em doentes com pancreatite aguda biliar Predictors of choledocholithiasis in patients sustaining acute biliary pancreatitis

    Directory of Open Access Journals (Sweden)

    José Gustavo Parreira

    2004-12-01

    Full Text Available OBJETIVO: Avaliar o papel da fosfatase alcalina (FA, gama glutamiltransferase (gamaGT e ultra-sonografia (US como fatores preditivos de coledocolitíase em doentes com pancreatite aguda biliar (PAB. MÉTODOS: Os dados foram coletados prospectivamente durante um período de 31 meses. Quarenta doentes foram incluídos, sendo 30 mulheres, com média etária de 49 + 16 anos. Foram registrados os dados de todos os doentes com pancreatite aguda biliar. Aqueles doentes ictéricos e com a forma grave da doença foram excluídos. As dosagens de FA e GGT, assim como a US, eram realizadas na admissão e 48 horas antes da cirurgia. Todos os pacientes foram submetidos à colangiografia intra-operatória (CIO ou à colangiografia retrógrada endoscópica (CPRE pré-operatória, que era definida baseada na probabilidade de coledocolitíase. Com o intuito de identificar os indicadores de coledocolitíase, as variáveis foram comparadas entre os pacientes com ou sem coledocolitíase. Os testes t de Student, Qui-quadrado e Fisher foram empregados para a análise estatística, considerando-se pBACKGROUND: To assess the role of alkaline phosphatase (AP, gamil-glutamyltransferase (gammaGT and abdominal ultrasound (US as predictors of choledocholithiasis in patients sustaining acute biliary pancreatitis. METHODS: Data was prospectively collected during a period of 31 months. Forty patients were included, 30 were female and the mean age was 49 + 16. All patients sustaining acute biliary pancreatitis were enrolled. Patients with clinical jaundice and severe pancreatitis were excluded. Serum content of AP and gGT as well as US were assessed at admission and 48 hours before cholecistectomy. All patients underwent intra-operative cholangiography (IOC or pre-operative endoscopic retrograde cholangiography (ERCP, which was indicated based on the odds of choledocholithiasis. In order to identify the predictors of choledocholithiasis, variables were compared between patients

  15. Principal Ports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Principal Ports are defined by port limits or US Army Corps of Engineers (USACE) projects, these exclude non-USACE projects not authorized for publication. The...

  16. Estudo ultrassonográfico morfométrico do fígado e trato biliar de suínos submetidos a obstrução biliar experimental

    Directory of Open Access Journals (Sweden)

    Aline Gomes de Campos

    2013-04-01

    Full Text Available OBJETIVO: Comparar as alterações anatômicas decorrentes de um quadro de icterícia obstrutiva experimental induzida em suínos nos períodos pré e pós-operatório por meio de exame ultrassonográfico. MATERIAIS E MÉTODOS: Seis suínos da raça Landrace, com 36 dias de idade, foram submetidos a obstrução biliar completa mediante ligadura do ducto colédoco por cirurgia videolaparoscópica. RESULTADOS: Não ocorreram dificuldades na execução dos procedimentos obstrutivos e a recuperação cirúrgica foi eficiente. Decorridos sete dias, os animais apresentaram icterícia, bilirrubinúria e acolia fecal. O exame ultrassonográfico comparativo permitiu visualizar hepatomegalia, colecistomegalia e aumento no calibre do ducto colédoco em todos os animais, assim como alterações decorrentes da colestase. A avaliação morfométrica revelou aumento significativo nos diâmetros da vesícula biliar e do lobo hepático lateral esquerdo. CONCLUSÃO: Os suínos representam um modelo experimental adequado de icterícia obstrutiva, e o exame ultrassonográfico demonstrou-se sensível e relevante no diagnóstico das alterações decorrentes de obstrução biliar extra-hepática nesses animais.

  17. Prevalência e fisiopatologia da litíase biliar em pacientes submetidos a transplante de órgãos

    OpenAIRE

    Coelho,Júlio Cesar Uili; Contieri,Fabiana Loss de; Matias,Jorge Eduardo Fouto; Parolin,Mônica Beatriz; Godoy,Jose Luiz de

    2009-01-01

    INTRODUÇÃO: O objetivo do presente estudo é apresentar revisão da prevalência e dos principais mecanismos fisiopatológicos que levam a formação da litíase biliar em pacientes submetidos a transplante de órgãos. MÉTODOS: Revisão da literatura abrangendo 29 publicações obtidas das bases Medline/Pubmed, Scielo e Lilacs com cruzamento dos unitermos "transplante, transplante renal, transplante hepático, cálculo biliar, colecistite.". Vários estudos que utilizaram a ultrassonografia demonstraram au...

  18. Principal components

    NARCIS (Netherlands)

    Hallin, M.; Hörmann, S.; Piegorsch, W.; El Shaarawi, A.

    2012-01-01

    Principal Components are probably the best known and most widely used of all multivariate analysis techniques. The essential idea consists in performing a linear transformation of the observed k-dimensional variables in such a way that the new variables are vectors of k mutually orthogonal

  19. Tratamento cirúrgico da atresia de vias biliares: a experiência do hospital municipal jesus, 1997-2000

    OpenAIRE

    Jesus, Lisieux Eyer de; Monteiro, Paulo Cesar Costa

    2001-01-01

    OBJETIVO: Analisar a indicação, resultados e limitações da portoenterostomia para o tratamento da atresia de vias biliares em hospital infantil terciário no Rio de Janeiro-RJ/Brasil. MÉTODO: Foram estudados prospectivamente oito pacientes submetidos à portoenterostomia do tipo Kasai 1, num período de três anos (1997-2000). Todos foram submetidos à antibioticoterapia profilática, uso de colerético, reavaliação médica mensal nos primeiros seis meses de seguimento e reavaliação laboratorial, ult...

  20. Atresia biliar: continuamos operando tarde Biliary atresia: we still operate too late

    Directory of Open Access Journals (Sweden)

    Carlos O. Kieling

    2008-10-01

    Full Text Available OBJETIVO: Analisar a idade na cirurgia de crianças com atresia biliar e a sobrevida sem necessidade de transplante de fígado. O estudo foi realizado no Hospital de Clínicas de Porto Alegre. MÉTODOS: Foram revisados os prontuários dos pacientes operados entre 1982 e 2007, residentes no Rio Grande do Sul. RESULTADOS: Dos 112 casos estudados de crianças com atresia biliar, 38 (33,9% ocorreram de 1982 a 1989, 46 (41,1% de 1990 a 1999 e 28 (25,0% a partir de 2000. Em 12 (10,7% casos, não foi realizada a portoenterostomia. A idade na cirurgia variou de 25 a 297 dias (mediana: 80,5; IIQ25-75: 61,3-109,0 dias; em 20,5% dos casos, a idade das crianças foi menor do que 60 dias. Não houve diferença na idade, no momento do diagnóstico, entre as 3 décadas. Os pacientes do interior do estado (mediana: 87,0; IIQ25-75: 69,0-115,0 dias foram encaminhados significativamente (p = 0,007 mais tarde do que os da região metropolitana de Porto Alegre (RS (mediana: 68,0; IIQ25-75: 55,5-98,0 dias. A proporção de pacientes com menos de 60 dias foi significativamente menor (p = 0,013 nos oriundos do interior. A sobrevida com fígado nativo do total dos pacientes foi de 46,2% em 2 anos, diminuindo progressivamente até 15,3% em 20 anos. Os pacientes operados com menos de 60 dias tiveram maior sobrevida com fígado nativo (log rank OBJECTIVE: To analyze the age at surgery for children with biliary atresia and their survival periods without need for liver transplantation. The study was performed at Hospital de Clínicas de Porto Alegre, in Porto Alegre, state of Rio Grande do Sul, Brazil. METHODS: The medical records of patients operated between 1982 and 2007 who were residents of the state of Rio Grande do Sul were reviewed. RESULTS: Of the 112 cases of children with biliary atresia studied, 38 (33.9% occurred between 1982 and 1989, 46 (41.1% between 1990 and 1999 and 28 (25.0% after 2000. Portoenterostomy was not performed for 12 cases (10.7%. Age at surgery

  1. Ant- and Ant-Colony-Inspired ALife Visual Art.

    Science.gov (United States)

    Greenfield, Gary; Machado, Penousal

    2015-01-01

    Ant- and ant-colony-inspired ALife art is characterized by the artistic exploration of the emerging collective behavior of computational agents, developed using ants as a metaphor. We present a chronology that documents the emergence and history of such visual art, contextualize ant- and ant-colony-inspired art within generative art practices, and consider how it relates to other ALife art. We survey many of the algorithms that artists have used in this genre, address some of their aims, and explore the relationships between ant- and ant-colony-inspired art and research on ant and ant colony behavior.

  2. Análise exploratória de adoçantes de mesa via espectroscopia no infravermelho (FTIR e análise por componentes principais (ACP Exploratory analysis of commercial sweeteners by infrared spectroscopy (FTIR and principal component analysis (PCA

    Directory of Open Access Journals (Sweden)

    Adriana Tozetto

    2007-12-01

    Full Text Available Nos últimos vinte anos, o consumo de alimentos diet e light tem aumentado sistematicamente, o que tem propiciado o constante desenvolvimento de produtos desse gênero. Grande ênfase tem sido dada àqueles produtos que substituem sacarose por edulcorantes de baixos conteúdos calóricos ou não calóricos. Seguindo esta tendência, adoçantes de mesa têm sido desenvolvidos variando-se amplamente o veículo e o tipo de edulcorante empregado. Neste trabalho, a análise de componentes principais associada à espectroscopia na região do infravermelho médio foi utilizada com sucesso para diferenciar os veículos empregados na produção destes adoçantes, sendo que esta metodologia quimiométrica reduziu o espaço dimensional para dois fatores, explicando cerca de 82-% da variância total dos dados. As variáveis responsáveis por esta discriminação estão localizadas na região da impressão digital do espectro de infravermelho (752,2 a 1284,5 cm-1. A análise exploratória mostrou-se útil para a visualização destes dados, gerando informações semiquantitativas para os adoçantes constituídos por lactose/aspartame, observações que seriam dificilmente visualizadas sem o recurso quimiométrico aplicado.In the last twenty years, the consumption of diet and light foods has grown steadily, leading to the constant development of such products. Much emphasis has been placed on products that replace sucrose with sweeteners of low or zero calorie content. The development of new commercial sweeteners illustrates this tendency. In this work, principal component analysis and infrared spectroscopy were used to successfully differentiate the vehicles (mediums employed in the production of sweeteners. This chemometric methodology reduced the dimensional space to two factors, accounting for 82% of the total variance of the data. The variables responsible for this discrimination were localized in the fingerprint region of the infrared spectrum (752.2 to

  3. Estudio por ecoendoscopia de la vía biliar extrahepática en pacientes con pancreatitis aguda biliar Endoscopic ultrasonographic examination of the common bile duct in patients with acute biliary pancreatitis

    Directory of Open Access Journals (Sweden)

    A. Repiso

    2008-06-01

    Full Text Available Objetivo: el objetivo de nuestro estudio fue valorar la utilidad de la ecoendoscopia en el estudio de la vía biliar extrahepática en los pacientes diagnosticados de pancreatitis aguda biliar y determinar los factores clínicos y analíticos relacionados con el resultado de la técnica. Material y métodos: se incluyeron en el estudio de modo consecutivo 73 pacientes (31 varones, 42 mujeres; media de edad 64 ± 15 años con pancreatitis aguda biliar remitidos a nuestro servicio para la realización de ecoendoscopia biliopancreática. En todos los pacientes se realizó la técnica seguida de CPRE con esfinterotomía y técnica endoscópica para la extracción de cálculos cuando se identificó por ecoendoscopia la existencia de coledocolitiasis. Se compararon las características clínico-evolutivas de estos pacientes con respecto al resultado obtenido con la ecoendoscopia. Resultados: la media de tiempo transcurrido desde el ingreso hasta la realización de la ecoendoscopia fue de 7 ± 6 días. En 18 pacientes (24% se observó en la ecoendoscopia la existencia de coledocolitiasis y en 17 de ellos se realizó esfinterotomía endoscópica. La presencia de coledocolitiasis fue más frecuente en aquellos pacientes con dilatación de la vía biliar extrahepática (55 vs. 14%; p 0,05. Tampoco se observó esta diferencia en el subgrupo de pacientes con pancreatitis aguda severa (45 vs. 55%; p > 0,05. Conclusiones: la ecoendoscopia es una técnica útil en la selección de los pacientes con pancreatitis aguda biliar que se beneficiarán de la realización de una esfinterotomía endoscópica.Objective: the objective of our study was to evaluate the usefulness of endoscopic ultrasonography (EUS for the study of the common bile duct in patients diagnosed with acute biliary pancreatitis, and to establish clinical and laboratory factors related to this technique. Materials and methods: seventy-three consecutive patients with acute biliary pancreatitis were

  4. Riding with the ants

    NARCIS (Netherlands)

    Duarte, A. P. M.; Attili-Angelis, D.; Baron, N. C.; Groenewald, Johannes Z.; Crous, Pedro W.; Pagnocca, F. C.

    Isolates of Teratosphaeriaceae have frequently been found in the integument of attine ants, proving to be common and diverse in this microenvironment. The LSU phylogeny of the ant-isolated strains studied revealed that they cluster in two main lineages. The first was associated with the genus

  5. Sick ants become unsociable

    DEFF Research Database (Denmark)

    Bos, Nicky Peter Maria; Lefevre, T.; Jensen, A.B.

    2012-01-01

    Parasites represent a severe threat to social insects, which form high-density colonies of related individuals, and selection should favour host traits that reduce infection risk. Here, using a carpenter ant (Camponotus aethiops) and a generalist insect pathogenic fungus (Metarhizium brunneum), we...... show that infected ants radically change their behaviour over time to reduce the risk of colony infection. Infected individuals (i) performed less social interactions than their uninfected counterparts, (ii) did not interact with brood anymore and (iii) spent most of their time outside the nest from...... day 3 post-infection until death. Furthermore, infected ants displayed an increased aggressiveness towards non-nestmates. Finally, infected ants did not alter their cuticular chemical profile, suggesting that infected individuals do not signal their physiological status to nestmates. Our results...

  6. Inserción de prótesis metálicas autoexpandibles totalmente recubiertas en patología biliar benigna

    Directory of Open Access Journals (Sweden)

    Mariana Omodeo

    Full Text Available RESUMEN Introducción: las enfermedades biliares benignas se han tratado, tradicionalmente, mediante la colocación de prótesis plásticas. Sin embargo, en la actualidad, las prótesis metálicas autoexpandibles totalmente recubiertas están ganando aceptación para el tratamiento de dichas patologías. Objetivo: evaluar la eficacia y las complicaciones de la inserción endoscópica temporal de prótesis metálicas totalmente recubiertas para el tratamiento de patologías biliares benignas. Materiales y métodos: estudio retrospectivo y observacional realizado a partir de una base de datos prospectiva en un centro de tercer nivel entre marzo de 2012 y mayo de 2016. Se incluyeron pacientes a los que se les colocó una prótesis metálica totalmente recubierta por patología benigna de la vía biliar. Se documentaron las indicaciones, las tasas de resolución, las de éxito técnico y los eventos adversos. Resultados: se incluyeron 31 pacientes a los que se insertaron 34 prótesis. Las indicaciones fueron las siguientes: 8 (25% estenosis biliares poscolecistectomía, 11 (31% coledocolitiasis de gran tamaño o múltiple, 3 (8,3% fístulas biliares, 2 (6% estenosis postrasplante hepático, 3 (8,3% estenosis papilares, 2 (6% perforaciones y 2 (6% sangrados. La tasa de éxito global de resolución de la patológica fue del 88%: 87,5% (7/8 en estenosis poscolecistectomía, 73% (8/11 en litiasis gigante, y 100% en el resto de las indicaciones. Se retiraron mediante endoscopia 33 de las 34 tras un promedio de 133 días (rango 10-180 días. No se registraron complicaciones. Conclusión: las prótesis metálicas autoexpandibles totalmente recubiertas son una alternativa efectiva y segura en la resolución de patologías biliares benignas.

  7. Commentary: Warring ants

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 27; Issue 2. Commentary: Warring ants: Lessons from Lanchester's laws of combat? Renee M Borges. Volume 27 Issue 2 March 2002 pp 75-78. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/jbsc/027/02/0075-0078 ...

  8. Antílope

    Directory of Open Access Journals (Sweden)

    Pedro Anderson Martinho Moçambique

    2015-10-01

    Full Text Available Essa espécie de antílope só é encontrada em território angolano, sendo assim um símbolo nacional. Segundo a mitologia africana é símbolo de vivacidade, velocidade e beleza - Angola.

  9. Antílope

    Directory of Open Access Journals (Sweden)

    Pedro Anderson Martinho Moçambique

    2011-04-01

    Full Text Available Essa espécie de antílope só é encontrada em território angolano, sendo assim um símbolo nacional. Segundo a mitologia africana é símbolo de vivacidade, velocidade e beleza - Angola.

  10. Fire Ant Allergy

    Science.gov (United States)

    ... venom in a fire ant sting will kill bacteria and some of your skin cells. This results in the formation of a blister that fills with a cloudy white material in about 24 hours. While this looks like a pus-filled lesion that should be drained, ...

  11. "Ant-egg" cataract revisited

    DEFF Research Database (Denmark)

    Clemmensen, Kåre; Enghild, Jan J; Ivarsen, Anders

    2017-01-01

    -ray scans and electron microscopy. The purpose of this study was to further characterize "ant-egg" cataract using modern technology and display the history of the "ant-eggs" after cataract extraction. METHODS: "Ant-eggs" were examined using Heidelberg SPECTRALIS Optical Coherence Tomography (OCT...

  12. Ant Colony Optimization for Control

    NARCIS (Netherlands)

    Van Ast, J.M.

    2010-01-01

    The very basis of this thesis is the collective behavior of ants in colonies. Ants are an excellent example of how rather simple behavior on a local level can lead to complex behavior on a global level that is beneficial for the individuals. The key in the self-organization of ants is communication

  13. Intra and extra hepathic biliary ducts of ducks (Anas boscas Vias biliares intra e extra-hepáticas de marreco-de-pequim (Anas boscas

    Directory of Open Access Journals (Sweden)

    Juarez Cezar Borges de Aquino

    2011-12-01

    Full Text Available A study in 38 liver of adults ducks from Jundiaí, state of São Paulo, was developed. After injection of Neoprene latex 650 colored by green and fixation in aqueous 10% formalin, the material was dissected under dental loupe, photographed and sketched. The intra hepatic bile ducts of the left lobe showed up in 76.3% the samples consisting of three collecting ducts bile; and 23.7% of the cases, there was the presence of one collector originated from caudal segment, draining to the hepatic duodenal duct. In the right lobe, in 100% of samples, were four collecting duct segments: cranium medial superficial, cranium medial deep, lateral and caudal (ventral caudal. With regard to biliary extra hepatic in 36 samples(94.7% it was composed of three ducts visible in hepatic hilum: hepatic duodenal, hepatic cystic and cystic duodenal. In two samples (5.3% was not observed hepatic cystic duct. The hepatic duodenal ductand cystic duodenal duct in 100% of the samples, they reached the duodenum. In six samples (15.8 %, besides the hepatic cystic duct, the gallbladder was achieved directly by bile collecting ducts of the right lobe. The gallbladder was not achieved by hepatic cystic duct in two samples (5.3 %. As vias biliares intra e extra-hepáticas de 38 marrecos-de-pequim adultos, provenientes de Jundiaí,estado de São Paulo, após injeção de Neoprene Látex 650 corado de verde e fixação em solução aquosa de formol a 10%, foram dissecados sob lupa odontológica, fotografados e desenhados esquematicamente. A via biliar intra-hepática no lobo esquerdo mostrou-se constituída por três ductos coletores biliares em 76,3% das amostras e, em 23,7% dos casos, está presente um quarto coletor, originado no segmentocaudal, drenando para o ducto hepatoduodenal. No lobo direito, em 100% das amostras ocorreram quatro ductos coletores dos segmentos craniomedial superficial, craniomedial profundo, lateral e caudal (ventrocaudal. No que se refere à via biliar

  14. Reação peritoneal tardia ao calculo biliar humano, de colesterol, deixado na cavidade abdominal de ratos

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Bertges

    Full Text Available Foram avaliados os resultados tardios da colocação de cálculos biliares humanos, de colesterol, na cavidade peritoneal de ratos. Constituíram-se cinco grupos: cinco ratos foram apenas laparotomizados com manuseio da cavidade; cinco foram laparotomizados e receberam um ponto com fio monofilamentar cinco zeros no sulco paracólico direito e mesentério; dez receberam cálculos que foram deixados livres na cavidade peritoneal; em dez, os clculos foram fixados no sulco paracólico direito e, finalmente, dez tiveram clculos fixados no mesentério. Os animais foram mortos após cinco meses de pós-operatório quando se observou a cavidade abdominal e foi coletado material para estudo histopatológico. Concluiu-se que os cálculos não foram absorvidos, desenvolveram uma reação peritoneal do tipo corpo estranho com formação de plastrão e foram envolvidos por tecido fibroso e células inflamatórias.

  15. Protection of Vochysia elliptica (Vochysiaceae by a nectar-thieving ant

    Directory of Open Access Journals (Sweden)

    G. Q. ROMERO

    Full Text Available Vochysia elliptica (Vochysiaceae is a shrubby plant, which does not have EFNs. Camponotus ants thieve nectar, and can decrease plant fitness by making flowers less attractive to pollinators. However, ants remove herbivores, wich can be beneficial. Results show that plants from which ants were excluded had lower rates of termite (simulated herbivore removal than did plants visited by ants. Plants accessible to ants showed higher rates of termite removal in the base of leaves and in the inflorescence, than in the tip of leaves. This occurs because ants must pass through the principal axis to reach the inflorescence. Conclusive results of this cost/benefit analysis of the Camponotus sp. presence for V. elliptica can be obtained, with experimental manipulations.

  16. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    Directory of Open Access Journals (Sweden)

    Alessandro Ossola

    2015-10-01

    Full Text Available Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i ant abundance and species richness would be higher in high-complexity urban habitats, (ii ant assemblages would differ between low- and high-complexity habitats and (iii ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.

  17. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    Science.gov (United States)

    Nash, Michael A.; Christie, Fiona J.; Hahs, Amy K.; Livesley, Stephen J.

    2015-01-01

    Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size. PMID:26528416

  18. Runtime analysis of the 1-ANT ant colony optimizer

    DEFF Research Database (Denmark)

    Doerr, Benjamin; Neumann, Frank; Sudholt, Dirk

    2011-01-01

    The runtime analysis of randomized search heuristics is a growing field where, in the last two decades, many rigorous results have been obtained. First runtime analyses of ant colony optimization (ACO) have been conducted only recently. In these studies simple ACO algorithms such as the 1-ANT...... that give us a more detailed impression of the 1-ANT’s performance. Furthermore, the experiments also deal with the question whether using many ant solutions in one iteration can decrease the total runtime....

  19. Acurácia diagnóstica do espessamento ecogênico periportal à ultra-sonografia e da histopatologia no diagnóstico diferencial da atresia biliar

    OpenAIRE

    Roquete,Mariza L. V.; Ferreira,Alexandre R.; Fagundes,Eleonora D. T.; Castro,Lúcia P. F.; Silva,Rogério A. P.; Penna,Francisco J.

    2008-01-01

    OBJETIVOS: Definir a sensibilidade, especificidade e a acurácia do espessamento ecogênico periportal à ultra-sonografia e da histopatologia hepática, isolados ou em conjunto, na distinção diagnóstica entre atresia biliar e as colestases intra-hepáticas. MÉTODOS: Trata-se de estudo retrospectivo realizado entre janeiro de 1990 e dezembro de 2004. Foram analisados 51 casos de atresia biliar e 45 com colestase intra-hepática. A histopatologia foi realizada por uma patologista de forma cega. O es...

  20. The metapleural gland of ants

    DEFF Research Database (Denmark)

    Yek, Sze Huei; Mueller, Ulrich G

    2011-01-01

    The metapleural gland (MG) is a complex glandular structure unique to ants, suggesting a critical role in their origin and ecological success. We synthesize the current understanding of the adaptive function, morphology, evolutionary history, and chemical properties of the MG. Two functions......-compressible invagination of the integument and the secretion is thought to ooze out passively through the non-closable opening of the MG or is groomed off by the legs and applied to target surfaces. MG loss has occurred repeatedly among the ants, particularly in the subfamilies Formicinae and Myrmicinae, and the MG...... is more commonly absent in males than in workers. MG chemistry has been characterized mostly in derived ant lineages with unique biologies (e.g. leafcutter ants, fire ants), currently precluding any inferences about MG chemistry at the origin of the ants. A synthetic approach integrating functional...

  1. Bacteriemia por Ochrobactrum anthropi en paciente con obstrucción de la vía biliar Bacteraemia by Ochrobactrum anthropi in patient with biliary obstruction

    Directory of Open Access Journals (Sweden)

    Sigifredo Ospina

    2009-12-01

    Full Text Available Reporte de caso de bacteriemia por Ochrobactrum anthropi con probable hepatitis bacteriana asociada, en un paciente inmunocompetente, el cual ingresa por sospecha de colangitis y obstrucción biliar. O. anthropi es una bacteria emergente en infecciones intrahospitalarias con notable resistencia antimicrobiana, y es un patógeno inusual en humanos.A case report of bacteraemia by Ochrobactrum anthropi probably associated with bacterial hepatitis, in a inmuno competent patient, who was admitted to the hospital with the diagnostic impression of cholangitis and biliary obstruction. O. anthropi is an emerging bacteria in nosocomial infections with remarkable antimicrobial resistance, being an unusual pathogen in humans.

  2. El ácido linoleico conjugado disminuye la hipercolesterolemia pero aumenta el riesgo de litiasis biliar Conjugated linoleic acid lowers hypercholesterolemia but increases the risk for biliary lithiasis

    OpenAIRE

    V. Navarro; M.ª T. Macarulla; M.ª Chávarri; A. Fernández-Quintela; V. M. Rodríguez; M.ª Puy Portillo

    2005-01-01

    El término ácido linoleico conjugado (ALC) designa una serie de isómeros del ácido linoleico, presentes en la carne y productos lácteos de rumiantes, que presentan sus dos dobles enlaces en posición conjugada. El objetivo del presente trabajo fue estudiar los efectos de un isómero del ALC, el trans-10, cis-12, sobre la colesterolemia y el riesgo de litiasis biliar en un modelo animal de hipercolesterolemia inducida por dieta. Para ello se utilizaron dos grupos de hámsters alimentados con una ...

  3. O espassamento ecogênico periportal e a histopatologia hepática no diagnóstico da atresia biliar

    OpenAIRE

    Mariza Leitao Valadares Roquete

    2006-01-01

    A colestase consiste na redução da formação da bile ou do fluxo biliar, cuja conseqüência é a retenção das substâncias excretadas na bile (Moyer et al., 2004). Uma grande parcela das afecções hepatobiliares de diversas naturezas manifestam-se com quadro de colestase. Estima-se que a colestase neonatal ocorra na freqüência de 1:2.500 nascidos vivos (Dick & Mowat, 1985)

  4. Síntesis y caracterización de surfactantes derivados de sales biliares, éteres corona, adamantanos y cadenas hidrocarbonadas

    OpenAIRE

    Trillo Novo, Juan Ventura

    2015-01-01

    La presente Tesis doctoral abarca aspectos relacionados con la Química supramolecular, el Biomimetismo molecular y la Fisicoquímica de coloides. El estudio ha implicado el diseño, la síntesis y la caracterización en disolución acuosa de numerosos compuestos entre los que sobresalen los derivados de las sales biliares, los éteres corona y grupos hidrófobos como los adamantanos y las cadenas hidrocarbonadas. Comparados con los surfactantes clásicos, los nuevos compuestos ev...

  5. Diferències pronòstiques en les pancreatitis agudes greus d'origen biliar i enòlic

    OpenAIRE

    Farré i Font, Roser

    2012-01-01

    Introducció: Les Pancreatitis Agudes (PA) es diagnostiquen amb dos dels tres criteris d'Atlanta: dolor abdominal, elevació d'amilases tres vegades per sobre del valor alt de la normalitat i TAC diagnòstic de PA. L'etiologia més prevalent en el nostre medi és la biliar (40-60%) seguit de l'alcohòlica (10-25%). Un 80% dels casos tenen un curs lleu amb reintroducció de la dieta i alta precoç mentre que un 20% són greus i requereixen tractament intensiu multidisciplinar. En el grup de PAG (pancre...

  6. Hospitales seguros ante desastres

    OpenAIRE

    Celso Vladimir Bambaren Alatrista; María Del Socorro Alatrista Gutierrez

    2007-01-01

    Entre 1982 a 2005 se registraron daños en 1 143 establecimientos de salud en el Perú, generalmente debido a sismos, lluvias e inundaciones. Los daños en los servicios de salud producen la interrupción de la atención de la población y de los programas de salud, así como generan un gran gasto para la rehabilitación y reconstrucción. Por ello, se requiere proteger a los establecimientos de salud y desarrollar una política de hospitales seguros ante desastres que incluya medidas para prevenir o r...

  7. La vivienda ante emergencias

    Directory of Open Access Journals (Sweden)

    Arq. María Eugenia Gonzàlez Chipont

    2014-12-01

    Full Text Available Este trabajo propone analizar la evolución de la vivienda como respuesta ante emergencias desde principios del siglo XX hasta nuestros días. La secuencia de casos a analizar no sigue una cronología estricta sino que se organiza en función de un creciente grado de complejidad. Comienza con los aportes fundamentales de la vivienda mínima del movimiento moderno, con un fuerte acento en lo tecnológico, para ir profundizando, mientras avanzamos en el siglo, en los aspectos sociales de la arquitectura. Sin intentar oponer lo tecnológico y lo social, la estructura propuesta expresa un enriquecimiento de la cuestión técnica conforme se van ampliando sus objetivos sociales. Mientras los requerimientos tecnológicos como la inmediatez y la masividad de la respuesta, permanecen a lo largo del tiempo, la vivienda ante emergencias puede plantearse objetivos sociales cada vez más profundos. Los casos fueron elegidos a partir de autores renombrados de la Historia de la Arquitectura partiendo de ejemplos cercanos a la génesis del movimiento moderno para acercarnos cada vez más hacia el contexto actual de Latinoamérica. Se logra así un barrido geográfco pero principalmente cultural: desde las fuentes de la modernidad, bajo el paradigma sólido de la industrialización, hasta la inestabilidad de la ciudad posindustrial latinoamericana

  8. Pest repellent properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2012-01-01

    of ant pheromones may be sufficient to repel pest insects from ant territories. The study of ant semiochemicals is in its infancy, yet, evidence for their potential use in pest management is starting to build up. Pheromones from four of five tested ant species have been shown to deter herbivorous insect...... prey and competing ant species are also deterred by ant deposits, whereas ant symbionts may be attracted to them. Based on these promising initial findings, it seems advisable to further elucidate the signaling properties of ant pheromones and to test and develop their use in future pest management....

  9. Hospitales seguros ante desastres

    Directory of Open Access Journals (Sweden)

    Celso Vladimir Bambaren Alatrista

    2007-07-01

    Full Text Available Entre 1982 a 2005 se registraron daños en 1 143 establecimientos de salud en el Perú, generalmente debido a sismos, lluvias e inundaciones. Los daños en los servicios de salud producen la interrupción de la atención de la población y de los programas de salud, así como generan un gran gasto para la rehabilitación y reconstrucción. Por ello, se requiere proteger a los establecimientos de salud y desarrollar una política de hospitales seguros ante desastres que incluya medidas para prevenir o reducción de la vulnerabilidad estructural, no estructural y funcional en los nuevos establecimientos y en los existentes.(Rev Med Hered 2007;18:149-154.

  10. A influência do tempo de referencia no tratamento das lesões iatrogênicas da via biliar

    Directory of Open Access Journals (Sweden)

    Fernando Barros

    Full Text Available OBJETIVO: Avaliar o prognóstico dos pacientes com lesão iatrogênica da via biliar (LIVB em relação ao tempo de referencia (TR para a unidade de transplante hepático (TH. MÉTODOS: Foram revisados 51 prontuários de pacientes que sofreram algum tipo de LIVB durante a colecistectomia e que foram encaminhados para a unidade de TH no Hospital Geral de Bonsucesso (HGB. As lesões foram agrupadas de acordo com a classificação de Bismuth. Além da colecistectomia (momento da lesão, também avaliamos o TR e o desfecho. RESULTADOS: Dentre os 51 pacientes estudados encontramos 17 homens e 34 mulheres com uma média de idade de 42,7 anos. Vinte e dois pacientes (43,1% tinham uma lesão do tipo II; 13 (25,5 % do tipo III; 10 (19,6 % do tipo I, 5 (9,8 % do tipo IV; e apenas um (2 % do tipo V. Quarenta pacientes foram operados, sendo que três não retornaram para revisão médica e portanto, 37 foram avaliados em relação ao desfecho. Dentre esses, 25 pacientes (67,6 % tiveram resultados excelentes ou bons com TR médio de 11,5 meses (intervalo: 2-48 meses e 47,2 meses (intervalo: 3-180 meses respectivamente. Os 12 pacientes (32,4 % com resultados ruins tiveram um TR médio de 65,9 meses (intervalo: 3-264 meses, que foi significativamente maior do que o grupo com resultados excelentes ou bons (p=0,004. Sete pacientes foram listadas para fila de TH, porém apenas dois foram realizados. O TR desses sete pacientes foi significativamente mais elevado (p=0,04 do que o daqueles pacientes não listados. Sete pacientes morreram, dos quais seis foram causados por complicações hepáticas. CONCLUSÃO: O TR influenciou significativamente no prognóstico dos pacientes da nossa amostra.

  11. Redesigning Principal Internships: Practicing Principals' Perspectives

    Science.gov (United States)

    Anast-May, Linda; Buckner, Barbara; Geer, Gregory

    2011-01-01

    Internship programs too often do not provide the types of experiences that effectively bridge the gap between theory and practice and prepare school leaders who are capable of leading and transforming schools. To help address this problem, the current study is directed at providing insight into practicing principals' views of the types of…

  12. Câncer de vesícula biliar: experiência de 10 anos em um hospital de referência da Amazônia

    Directory of Open Access Journals (Sweden)

    Geraldo Ishak

    Full Text Available OBJETIVO: Analisar os aspectos epidemiológicos-cirúrgicos dos pacientes com câncer de vesícula biliar (CAVB atendidos em um Hospital Universitário de Belém/PA, no período de 1999-2009. MÉTODOS: estudo observacional, retrospectivo, descritivo-analítico de fonte secundária dos pacientes com diagnóstico de CAVB, no período de 1999-2009. Foram analisados 75 prontuários, sendo 34 pacientes estudados. As informações coletadas foram utilizadas para o estadiamento tumoral TNM do CAVB e para a caracterização clínico-cirúrgica da população estudada. RESULTADOS: 79% eram do sexo feminino, com média de idade de 66,2±11 anos e tempo de sintomatologia de 10,8±17,2 meses, não obtendo relação estatística com o estadio da doença. Dor no hipocôndrio direito, náuseas e icterícia predominaram como sinais/sintomas. A litíase biliar esteve presente em 91% dos casos, sendo positiva em 100% dos pacientes com estadios I/II. A sensibilidade ultrassonográfica para sugestionar o CAVB no pré-operatório foi 14,28%. A operação mais executada foi a colecistectomia simples, tendo como achado intra-operatório predominante, invasão hepática. O adenocarcinoma foi o tipo histológico preponderante, com destaque para os estadios III e IV. CONCLUSÃO: A série estudada apresentou alta incidência de litíase biliar, o adenocarcinoma com estadio avançado foi o mais prevalente. acarretando um pequeno índice de operações com intenção curativa, 30% dos pacientes operados, e uma taxa de mortalidade de 21%. A valorização dos sintomas e a investigação precoce por exames de imagem poderiam favorecer o tratamento, em fases iniciais do CAVB, proporcionando um melhor prognóstico para os pacientes operados.

  13. A cellular automata model for ant trails

    Indian Academy of Sciences (India)

    In this study, the unidirectional ant traffic flow with U-turn in an ant trail was inves- tigated using ... the literature, it was considered in the model that (i) ant colony consists of two kinds of ants, good- ... ponents without a central controller [8].

  14. ANT, tourism and situated globality

    DEFF Research Database (Denmark)

    Jóhannesson, Gunnar Thór; Ren, Carina Bregnholm; van der Duim, René

    2015-01-01

    viable descriptions of the collective condition of humans and more-than-humans in the Anthropocene. Also and moving past a merely descriptive approach, it discusses it as a useful tool to engage with the situated globalities which come into being through the socio-spatial coupling of tourism......In recent years Actor-network theory (ANT) has increasingly been felt in the field of tourism studies (Van der Duim, Ren, & Jóhannesson, 2012). An important implication of the meeting between ANT and tourism studies is the notion of tourism being described as a heterogeneous assemblage of what we...... are used to define as the separate spheres of nature and culture. This paper explores and relates the central tenets of ANT in tourism with regard to the concept of the Anthropocene. It presents the ANT approach as a flat and object-oriented ontology and methodology and explores its potentials to carve out...

  15. What Motivates Principals?

    Science.gov (United States)

    Iannone, Ron

    1973-01-01

    Achievement and recognition were mentioned as factors appearing with greater frequency in principal's job satisfactions; school district policy and interpersonal relations were mentioned as job dissatisfactions. (Editor)

  16. Principal Ports and Facilities

    Data.gov (United States)

    California Natural Resource Agency — The Principal Port file contains USACE port codes, geographic locations (longitude, latitude), names, and commodity tonnage summaries (total tons, domestic, foreign,...

  17. Principal Ports and Facilities

    Data.gov (United States)

    California Department of Resources — The Principal Port file contains USACE port codes, geographic locations (longitude, latitude), names, and commodity tonnage summaries (total tons, domestic, foreign,...

  18. Ants Orase kultuurisõnum

    Index Scriptorium Estoniae

    2007-01-01

    26. jaanuaril toimub Tallinna Ülikooli Akadeemilises Raamatukogus seminar silmapaistvast Eesti teadlasest ja tõlkijast Ants Orasest. Esinevad kirjandusteadlased Tallinna Ülikoolist, Tartu Ülikoolist ja Eesti Kirjandusmuuseumist. Avaettekandeks on sõna Oklahoma Ülikooli professoril Vincent B. Leitchil, kes oli Ants Orase viimaseks juhendatavaks doktorandiks. Seminari korraldavad Tallinna Ülikool ja Eesti Kirjandusmuuseum. Vt ka Postimees, 26, jaan., lk. 18

  19. Usefulness of endoscopic ultrasonography in the clinical suspicion of biliary disease Utilidad de la ultrasonografía endoscópica en la sospecha clínica de patología biliar

    Directory of Open Access Journals (Sweden)

    David del Pozo

    2011-07-01

    Full Text Available Background and aims: endoscopic ultrasound (EUS is a very sensitive and specific technique for the diagnosis of biliary diseases. This procedure has proven its usefulness in cases of high suspicion of biliary disease (history of gallstones and dilatation of the intrahepatic and/or extrahepatic bile ducts. We know less about its usefulness in cases of low suspicion of biliary pathology. The aim of this study was to assess the diagnostic accuracy of EUS in patients with low suspicion of biliary disease (patients with dilatation of the biliary tract were excluded. Methods: 33 patients with low suspicion of biliary disease were recruited in 12 months. All of them had no biliary findings in a previous abdominal ultrasound and computer tomography scan. All of them underwent EUS and were studied prospectively. The diagnosis was confirmed by surgery and/or by ERCP in patients with positive EUS or clinical follow-up in those with normal EUS. Time of follow-up was 9 months (range, 3-12 months. Results: seventeen patients (51.5% presented with abnormal biliary findings on EUS (7 choledocholithiasis, 3 cholelithiasis, 2 choledocholithiasis + cholelithiasis and 5 microlithiasis. Conclusion: EUS is a useful and safe procedure for diagnosing patients with low suspicion of biliary disease.Antecedentes y objetivos: la ultrasonografía endoscópica (USE es una técnica muy sensible y específica para el diagnóstico de enfermedades biliares. Este procedimiento ha demostrado su utilidad en casos de alta sospecha de enfermedad biliar (historia de colelitiasis y dilatación de la vía biliar intra- y/o extrahepática. Sabemos menos sobre su utilidad en casos de baja sospecha de patología biliar. El objetivo de este estudio fue evaluar la precisión diagnóstica de la USE en pacientes con baja sospecha de enfermedad biliar (los pacientes con dilatación de la vía biliar fueron excluidos. Métodos: 33 pacientes con baja sospecha de enfermedad biliar fueron

  20. Principals' Perceptions of Politics

    Science.gov (United States)

    Tooms, Autumn K.; Kretovics, Mark A.; Smialek, Charles A.

    2007-01-01

    This study is an effort to examine principals' perceptions of workplace politics and its influence on their productivity and efficacy. A survey was used to explore the perceptions of current school administrators with regard to workplace politics. The instrument was disseminated to principals serving public schools in one Midwestern state in the…

  1. Renewing the Principal Pipeline

    Science.gov (United States)

    Turnbull, Brenda J.

    2015-01-01

    The work principals do has always mattered, but as the demands of the job increase, it matters even more. Perhaps once they could maintain safety and order and call it a day, but no longer. Successful principals today must also lead instruction and nurture a productive learning community for students, teachers, and staff. They set the tone for the…

  2. Using Ants as bioindicators: Multiscale Issues in Ant Community Ecology

    Directory of Open Access Journals (Sweden)

    Alan Andersen

    1997-06-01

    Full Text Available Ecological patterns and processes are characteristically scale dependent, and research findings often cannot be translated easily from one scale to another. Conservation biology is challenged by a lack of congruence between the spatial scales of ecological research (typically involving small plots and land management (typically involving whole landscapes. Here, I discuss spatial scaling issues as they relate to an understanding of ant communities and, consequently, their use as bioindicators in land management. Our perceptions of fundamental patterns and processes in ant communities depend on scale: taxa that are behaviorally dominant at one scale are not necessarily so at others, functional groups recognized at one scale are often inappropriate for others, and the role of competition in community structure depends on the scale of analysis. Patterns of species richness and composition, and the ability of total richness to be estimated by surrogates, are all also scale dependent. Ant community ecology has a tradition of detailed studies in small plots, but the use of ants as bioindicators requires a predictive understanding of community structure and dynamics at a range of spatial scales. Such an appreciation of ant communities and their most effective use as bioindicators is best served by studies integrating results from plot-scale research with the broad-scale paradigms of biogeography, systematics, and evolutionary biology.

  3. Fatores relacionados ao prognóstico da atresia biliar pós-portoenterostomia Factors related to the post-portoenterostomy prognosis of biliary atresia

    Directory of Open Access Journals (Sweden)

    Jorge Luiz dos Santos

    2002-01-01

    Full Text Available Objetivo: o estudo está envolvido com o prognóstico da atresia biliar pós-portoenterostomia, presença de anomalias congênitas associadas à doença e de malformação de placa ductal, área de fibrose hepática e, sobretudo, com a idade dos pacientes por ocasião da cirurgia. O presente estudo verificou numa amostra de atresia biliar as implicações prognósticas destes fatores. Métodos: foram avaliados 47 pacientes com atresia biliar, em estudo de corte transversal. O material histológico dos casos foi marcado com anticorpo anticitoqueratina 19 e CAM 5.2 por método imunoistoquímico, para o estudo das estruturas biliares, e corado com picrossírius para avaliação da área de fibrose. O estudo das estruturas biliares foi realizado por dois patologistas e pelo primeiro autor deste estudo, "cegos" quanto à evolução dos casos. A mensuração da área de fibrose foi quantitativa. Os dados dos pacientes em relação à idade, ocorrência de óbito ou realização de transplante hepático foram pesquisados nos prontuários. Resultados: a idade por ocasião da portoenterostomia variou entre 24 e 251 dias de vida (90,4 + 44,8 dias, e em 32 casos (72% a evolução pôde ser acompanhada. Os 9 casos (19% com anomalias congênitas extra-hepáticas associadas não diferiram quanto ao prognóstico em relação ao restante da amostra. A idade por ocasião da portoenterostomia influenciou o prognóstico (p=0,016. A área de fibrose foi diferente entre pacientes operados com menos de 60 dias de vida e os operados com mais de 90 dias (p= 0,023, mas não influenciou a evolução dos casos. Tampouco a presença de malformação de placa ductal influiu no prognóstico. Conclusões: a idade por ocasião da portoenterostomia foi o único fator que afetou o prognóstico dos casos de atresia biliar. É necessário maior número de pacientes para avaliar a influência da presença de anomalias congênitas extra-hepáticas associadas sobre a evolução p

  4. Monoculture of leafcutter ant gardens.

    Directory of Open Access Journals (Sweden)

    Ulrich G Mueller

    2010-09-01

    Full Text Available Leafcutter ants depend on the cultivation of symbiotic Attamyces fungi for food, which are thought to be grown by the ants in single-strain, clonal monoculture throughout the hundreds to thousands of gardens within a leafcutter nest. Monoculture eliminates cultivar-cultivar competition that would select for competitive fungal traits that are detrimental to the ants, whereas polyculture of several fungi could increase nutritional diversity and disease resistance of genetically variable gardens.Using three experimental approaches, we assessed cultivar diversity within nests of Atta leafcutter ants, which are most likely among all fungus-growing ants to cultivate distinct cultivar genotypes per nest because of the nests' enormous sizes (up to 5000 gardens and extended lifespans (10-20 years. In Atta texana and in A. cephalotes, we resampled nests over a 5-year period to test for persistence of resident cultivar genotypes within each nest, and we tested for genetic differences between fungi from different nest sectors accessed through excavation. In A. texana, we also determined the number of Attamyces cells carried as a starter inoculum by a dispersing queens (minimally several thousand Attamyces cells, and we tested for genetic differences between Attamyces carried by sister queens dispersing from the same nest. Except for mutational variation arising during clonal Attamyces propagation, DNA fingerprinting revealed no evidence for fungal polyculture and no genotype turnover during the 5-year surveys.Atta leafcutter ants can achieve stable, fungal monoculture over many years. Mutational variation emerging within an Attamyces monoculture could provide genetic diversity for symbiont choice (gardening biases of the ants favoring specific mutational variants, an analog of artificial selection.

  5. Pest repelling properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2014-01-01

    Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini-review sh......-review shows that four out of five tested ant species deposit pheromones that repel herbivorous prey from their host plants.......Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini...

  6. How ants drop out: ant abundance on tropical mountains.

    Science.gov (United States)

    Longino, John T; Branstetter, Michael G; Colwell, Robert K

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

  7. How ants drop out: ant abundance on tropical mountains.

    Directory of Open Access Journals (Sweden)

    John T Longino

    Full Text Available In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica and examined the impact of elevation (as a proxy for temperature and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

  8. Multiscale principal component analysis

    International Nuclear Information System (INIS)

    Akinduko, A A; Gorban, A N

    2014-01-01

    Principal component analysis (PCA) is an important tool in exploring data. The conventional approach to PCA leads to a solution which favours the structures with large variances. This is sensitive to outliers and could obfuscate interesting underlying structures. One of the equivalent definitions of PCA is that it seeks the subspaces that maximize the sum of squared pairwise distances between data projections. This definition opens up more flexibility in the analysis of principal components which is useful in enhancing PCA. In this paper we introduce scales into PCA by maximizing only the sum of pairwise distances between projections for pairs of datapoints with distances within a chosen interval of values [l,u]. The resulting principal component decompositions in Multiscale PCA depend on point (l,u) on the plane and for each point we define projectors onto principal components. Cluster analysis of these projectors reveals the structures in the data at various scales. Each structure is described by the eigenvectors at the medoid point of the cluster which represent the structure. We also use the distortion of projections as a criterion for choosing an appropriate scale especially for data with outliers. This method was tested on both artificial distribution of data and real data. For data with multiscale structures, the method was able to reveal the different structures of the data and also to reduce the effect of outliers in the principal component analysis

  9. Male parentage in army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel J C; Schöning, Caspar; Boomsma, Jacobus J

    2006-01-01

    of active research in insect sociobiology. Here we present microsatellite data for 176 males from eight colonies of the African army ant Dorylus (Anomma) molestus. Comparison with worker genotypes and inferred queen genotypes from the same colonies show that workers do not or at best very rarely reproduce...

  10. A cellular automata model for ant trails

    Indian Academy of Sciences (India)

    In this study, the unidirectional ant traffic flow with U-turn in an ant trail was investigated using one-dimensional cellular automata model. It is known that ants communicate with each other by dropping a chemical, called pheromone, on the substrate. Apart from the studies in the literature, it was considered in the model that ...

  11. Fungal Adaptations to Mutualistic Life with Ants

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus

    Fungus-growing ants (Attini) feed off a fungus they cultivate in a mutualistic symbiosis in underground chambers by providing it substrate they collect outside the colony. The tribe of Attine ants ranges from small colonies of the paleo- and basal Attine species with a few hundred workers that fo...... that the fungus evolved some incredible adaptations to a mutualistic life with the ants....

  12. Estudo ultrassonográfico morfométrico do fígado e trato biliar de suínos submetidos a obstrução biliar experimental Sonographic morphometry of the liver and biliary tract in porcine models submitted to experimental biliary obstruction

    Directory of Open Access Journals (Sweden)

    Aline Gomes de Campos

    2013-04-01

    Full Text Available OBJETIVO: Comparar as alterações anatômicas decorrentes de um quadro de icterícia obstrutiva experimental induzida em suínos nos períodos pré e pós-operatório por meio de exame ultrassonográfico. MATERIAIS E MÉTODOS: Seis suínos da raça Landrace, com 36 dias de idade, foram submetidos a obstrução biliar completa mediante ligadura do ducto colédoco por cirurgia videolaparoscópica. RESULTADOS: Não ocorreram dificuldades na execução dos procedimentos obstrutivos e a recuperação cirúrgica foi eficiente. Decorridos sete dias, os animais apresentaram icterícia, bilirrubinúria e acolia fecal. O exame ultrassonográfico comparativo permitiu visualizar hepatomegalia, colecistomegalia e aumento no calibre do ducto colédoco em todos os animais, assim como alterações decorrentes da colestase. A avaliação morfométrica revelou aumento significativo nos diâmetros da vesícula biliar e do lobo hepático lateral esquerdo. CONCLUSÃO: Os suínos representam um modelo experimental adequado de icterícia obstrutiva, e o exame ultrassonográfico demonstrou-se sensível e relevante no diagnóstico das alterações decorrentes de obstrução biliar extra-hepática nesses animais.OBJECTIVE: To compare, by means of ultrasonography, pre- and postoperative anatomical changes arising from experimentally induced obstructive jaundice in porcine models. MATERIALS AND METHODS: Six 36-day-old Landrace pigs underwent laparoscopically induced complete biliary obstruction by common bile duct ligation. RESULTS: No difficulty was faced during the procedures and the surgical recovery was uneventful. After seven days, the animals showed jaundice, bilirubinuria and acholic stools. Comparative ultrasonography allowed visualization of hepatomegaly, cholecystomegaly and increased caliber of the common bile duct in all the animals, as well as changes resulting from cholestasis. The morphometric analysis revealed a significant increase in diameter of the

  13. Principal noncommutative torus bundles

    DEFF Research Database (Denmark)

    Echterhoff, Siegfried; Nest, Ryszard; Oyono-Oyono, Herve

    2008-01-01

    of bivariant K-theory (denoted RKK-theory) due to Kasparov. Using earlier results of Echterhoff and Williams, we shall give a complete classification of principal non-commutative torus bundles up to equivariant Morita equivalence. We then study these bundles as topological fibrations (forgetting the group...

  14. The Principal as CEO

    Science.gov (United States)

    Hollar, Charlie

    2004-01-01

    They may never grace the pages of The Wall Street Journal or Fortune magazine, but they might possibly be the most important CEOs in our country. They are elementary school principals. Each of them typically serves the learning needs of 350-400 clients (students) while overseeing a multimillion-dollar facility staffed by 20-25 teachers and 10-15…

  15. Euler principal component analysis

    NARCIS (Netherlands)

    Liwicki, Stephan; Tzimiropoulos, Georgios; Zafeiriou, Stefanos; Pantic, Maja

    Principal Component Analysis (PCA) is perhaps the most prominent learning tool for dimensionality reduction in pattern recognition and computer vision. However, the ℓ 2-norm employed by standard PCA is not robust to outliers. In this paper, we propose a kernel PCA method for fast and robust PCA,

  16. Microsatellite Primers for Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  17. Microsatellite primers for fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Gertsch, P J; Boomsma, JJ

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  18. Serum oxidative stress is increased in patients with post cholecystectomy bile duct injury Aumento del estrés oxidativo en el suero de pacientes con lesiones de vías biliares postcolecistectomía

    Directory of Open Access Journals (Sweden)

    A. G. Miranda-Díaz

    2010-06-01

    Full Text Available Background: post-cholecystectomy bile duct injuries are identified by the onset of jaundice as well as elevated bilirubin and alkaline phosphatase levels during the peri-operative period. It is unknown how serum oxidative stress markers are modified in patients with post-cholecystectomy bile duct injuries. Objective: to determine serum oxidative stress marker levels (lipid peroxidation by-products, nitrites/nitrates and total antioxidant capacity in patients with post-cholecystectomy bile duct injuries. Patients and methods: a prospective, transversal and analytical study was designed with two groups. Group 1: 5 healthy volunteer subjects. Group 2: 52 patients with post-cholecystectomy bile duct injuries (43 female and 9 male. An elective bilio-digestive reconstruction was performed at week 8. The serum oxidative stress marker levels were quantified by colorimetric method. Results: patients with bile duct injuries had a significant increased serum lipid peroxides (malondialdehyde and 4-hydroxy-alkenals and nitric oxide metabolites (nitrites/nitrates levels compared to the control group. In contrast, total antioxidant capacity in patients with bile duct injuries remained similar compared to healthy controls. Conclusions: the results show that oxidative stress is usually associated to bile duct injury.Introducción: las lesiones de las vías biliares postcolecistectomía se establecen por la aparición de ictericia, elevación de las bilirrubinas y de la fosfatasa alcalina durante el periodo perioperatorio. Se desconoce cómo se modifican los marcadores de estrés oxidativo en el suero de los pacientes con lesiones de las vías biliares postcolecistectomía. Objetivo: determinar los marcadores de estrés oxidativo (productos de peroxidación de lípidos, catabolitos del óxido nítrico y capacidad antioxidante total en el suero de pacientes con lesiones de las vías biliares. Pacientes y métodos: se realizó un estudio prospectivo transversal

  19. Revolutionizing Remote Exploration with ANTS

    Science.gov (United States)

    Clark, P. E.; Rilee, M. L.; Curtis, S.; Truszkowski, W.

    2002-05-01

    We are developing the Autonomous Nano-Technology Swarm (ANTS) architecture based on an insect colony analogue for the cost-effective, efficient, systematic survey of remote or inaccessible areas with multiple object targets, including planetary surface, marine, airborne, and space environments. The mission context is the exploration in the 2020s of the most compelling remaining targets in the solar system: main belt asteroids. Main belt asteroids harbor important clues to Solar System origins and evolution which are central to NASA's goals in Space Science. Asteroids are smaller than planets, but their number is far greater, and their combined surface area likely dwarfs the Earth's. An asteroid survey will dramatically increase our understanding of the local resources available for the Human Exploration and Development of Space. During the mission composition, shape, gravity, and orbit parameters could be returned to Earth for perhaps several thousand asteroids. A survey of this area will rival the great explorations that encircled this globe, opened up the New World, and laid the groundwork for the progress and challenges of the last centuries. The ANTS architecture for a main belt survey consists of a swarm of as many as a thousand or more highly specialized pico-spacecraft that form teams to survey as many as one hundred asteroids a month. Multi-level autonomy is critical for ANTS and the objective of the proposed study is to work through the implications and constraints this entails. ANTS couples biologically inspired autonomic control for basic functions to higher level artificial intelligence that together enable individual spacecraft to operate as specialized, cooperative, social agents. This revolutionary approach postulates highly advanced, but familiar, components integrated and operated in a way that uniquely transcends any evolutionary extrapolation of existing trends and enables thousand-spacecraft missions.

  20. Ant-plant mutualism: a dietary by-product of a tropical ant's macronutrient requirements.

    Science.gov (United States)

    Arcila Hernández, Lina M; Sanders, Jon G; Miller, Gabriel A; Ravenscraft, Alison; Frederickson, Megan E

    2017-12-01

    Many arboreal ants depend on myrmecophytic plants for both food and shelter; in return, these ants defend their host plants against herbivores, which are often insects. Ant-plant and other mutualisms do not necessarily involve the exchange of costly rewards or services; they may instead result from by-product benefits, or positive outcomes that do not entail a cost for one or both partners. Here, we examined whether the plant-ant Allomerus octoarticulatus pays a short-term cost to defend their host plants against herbivores, or whether plant defense is a by-product benefit of ant foraging for insect prey. Because the food offered by ant-plants is usually nitrogen-poor, arboreal ants may balance their diets by consuming insect prey or associating with microbial symbionts to acquire nitrogen, potentially shifting the costs and benefits of plant defense for the ant partner. To determine the effect of ant diet on an ant-plant mutualism, we compared the behavior, morphology, fitness, stable isotope signatures, and gaster microbiomes of A. octoarticulatus ants nesting in Cordia nodosa trees maintained for nearly a year with or without insect herbivores. At the end of the experiment, ants from herbivore exclosures preferred protein-rich baits more than ants in the control (i.e., herbivores present) treatment. Furthermore, workers in the control treatment were heavier than in the herbivore-exclusion treatment, and worker mass predicted reproductive output, suggesting that foraging for insect prey directly increased ant colony fitness. The gaster microbiome of ants was not significantly affected by the herbivore exclusion treatment. We conclude that the defensive behavior of some phytoecious ants is a by-product of their need for external protein sources; thus, the consumption of insect herbivores by ants benefits both the ant colony and the host plant. © 2017 by the Ecological Society of America.

  1. Ecosystem services delivered by weaver ants

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    Weaver ants (Oecopgylla spp.) are increasingly being utilized as efficient biocontrol agents in a number of tropical tree crops, as they prey on pest insects and increase yields. However, recent studies and a review of the literature reveal that a number of other services may derive from the pres......Weaver ants (Oecopgylla spp.) are increasingly being utilized as efficient biocontrol agents in a number of tropical tree crops, as they prey on pest insects and increase yields. However, recent studies and a review of the literature reveal that a number of other services may derive from...... the presence of these ants. First of all, the chemical footprint left by the high density of ants in managed host trees may results in additional benefits. (i) Ant deposits may lead to improved fruit quality, e.g. increased sugar content, (ii) ant deposits may deter important pests (chemical deterrence) from...... crops, and lastly, (iii) ant waste products deposited ias anal spots contain urea that may be taken up by plant leaves and in this way fertilize ant-plants. On top of chemical services, weaver ants have been shown to reduce plant disease incidence via competitive exclusion of other ant species because...

  2. Roadside Survey of Ants on Oahu, Hawaii

    Science.gov (United States)

    Tong, Reina L.; Grace, J. Kenneth; Krushelnycky, Paul D.

    2018-01-01

    Hawaii is home to over 60 ant species, including five of the six most damaging invasive ants. Although there have been many surveys of ants in Hawaii, the last island-wide hand-collection survey of ants on Oahu was conducted in 1988–1994. In 2012, a timed hand-collection of ants was made at 44 sites in a systematic, roadside survey throughout Oahu. Ants were identified and species distribution in relation to elevation, precipitation and soil type was analyzed. To assess possible convenience sampling bias, 15 additional sites were sampled further from roads to compare with the samples near roads. Twenty-four species of ants were found and mapped; Pheidole megacephala (F.), Ochetellus glaber (Mayr), and Technomyrmex difficilis Forel were the most frequently encountered ants. For six ant species, a logistic regression was performed with elevation, average annual precipitation, and soil order as explanatory variables. O. glaber was found in areas with lower precipitation around Oahu. Paratrechina longicornis (Latrielle) and Tetramorium simillimum (Smith, F.) were found more often in lower elevations and in areas with the Mollisol soil order. Elevation, precipitation, and soil type were not significant sources of variation for P. megacephala, Plagiolepis alluaudi Emery, and T. difficilis. P. megacephala was associated with fewer mean numbers of ants where it occurred. Ant assemblages near and far from roads did not significantly differ. Many species of ants remain established on Oahu, and recent invaders are spreading throughout the island. Mapping ant distributions contributes to continued documentation and understanding of these pests. PMID:29439503

  3. Autonomous Agents on Expedition: Humans and Progenitor Ants and Planetary Exploration

    Science.gov (United States)

    Rilee, M. L.; Clark, P. E.; Curtis, S. A.; Truszkowski, W. F.

    2002-01-01

    The Autonomous Nano-Technology Swarm (ANTS) is an advanced mission architecture based on a social insect analog of many specialized spacecraft working together to achieve mission goals. The principal mission concept driving the ANTS architecture is a Main Belt Asteroid Survey in the 2020s that will involve a thousand or more nano-technology enabled, artificially intelligent, autonomous pico-spacecraft (architecture. High level, mission-oriented behaviors are to be managed by a control / communications layer of the swarm, whereas common low level functions required of all spacecraft, e.g. attitude control and guidance and navigation, are handled autonomically on each spacecraft. At the higher levels of mission planning and social interaction deliberative techniques are to be used. For the asteroid survey, ANTS acts as a large community of cooperative agents while for precursor missions there arises the intriguing possibility of Progenitor ANTS and humans acting together as agents. For optimal efficiency and responsiveness for individual spacecraft at the lowest levels of control we have been studying control methods based on nonlinear dynamical systems. We describe the critically important autonomous control architecture of the ANTS mission concept and a sequence of partial implementations that feature increasingly autonomous behaviors. The scientific and engineering roles that these Progenitor ANTS could play in human missions or remote missions with near real time human interactions, particularly to the Moon and Mars, will be discussed.

  4. Cultural differences in ant-dipping tool length between neighbouring chimpanzee communities at Kalinzu, Uganda.

    Science.gov (United States)

    Koops, Kathelijne; Schöning, Caspar; Isaji, Mina; Hashimoto, Chie

    2015-07-22

    Cultural variation has been identified in a growing number of animal species ranging from primates to cetaceans. The principal method used to establish the presence of culture in wild populations is the method of exclusion. This method is problematic, since it cannot rule out the influence of genetics and ecology in geographically distant populations. A new approach to the study of culture compares neighbouring groups belonging to the same population. We applied this new approach by comparing ant-dipping tool length between two neighbouring communities of chimpanzees (Pan troglodytes schweinfurthii) in the Kalinzu Forest, Uganda. Ant-dipping tool length varies across chimpanzee study sites in relation to army ant species (Dorylus spp.) and dipping location (nest vs. trail). We compared the availability of army ant species and dipping tool length between the two communities. M-group tools were significantly longer than S-group tools, despite identical army ant target species availabilities. Moreover, tool length in S-group was shorter than at all other sites where chimpanzees prey on epigaeic ants at nests. Considering the lack of ecological differences between the two communities, the tool length difference appears to be cultural. Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring chimpanzee communities.

  5. Ant Larval Demand Reduces Aphid Colony Growth Rates in an Ant-Aphid Interaction

    Directory of Open Access Journals (Sweden)

    James M. Cook

    2012-02-01

    Full Text Available Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown whether demand from within the ant colony can affect the ant-aphid interaction. In a factorial experiment, we tested whether the presence of larvae in Lasius niger ant colonies affected the growth rate of Aphis fabae colonies. Other explanatory variables tested were the origin of ant colonies (two separate colonies were used and previous diet (sugar only or sugar and protein. We found that the presence of larvae in the ant colony significantly reduced the growth rate of aphid colonies. Previous diet and colony origin did not affect aphid colony growth rates. Our results suggest that ant colonies balance the flow of two separate resources from aphid colonies- renewable sugars or a protein-rich meal, depending on demand from ant larvae within the nest. Aphid payoffs from the ant-aphid interaction may change on a seasonal basis, as the demand from larvae within the ant colony waxes and wanes.

  6. The distribution and diversity of insular ants

    DEFF Research Database (Denmark)

    Roura-Pascual, Núria; Sanders, Nate; Hui, Cang

    2016-01-01

    Aim: To examine the relationship between island characteristics (area, distance to the nearest continent, climate and human population size) and ant species richness, as well as the factors underlying global geographical clustering of native and exotic ant composition on islands. Location: One...... hundred and two islands from 20 island groups around the world. Methods: We used spatial linear models that consider the spatial structure of islands to examine patterns of ant species richness. We also performed modularity analyses to identify clusters of islands hosting a similar suite of species...... and constructed conditional inference trees to assess the characteristics of islands that explain the formation of these island-ant groups. Results: Island area was the best predictor of ant species richness. However, distance to the nearest continent was an important predictor of native ant species richness...

  7. Avaliação da contratilidade da vesícula biliar com leite materno e leite de vaca em lactentes Gallbladder contractility after breast milk and cow's milk meals in infants

    Directory of Open Access Journals (Sweden)

    Marise Silva Teixeira

    2004-06-01

    Full Text Available As múltiplas características distintas do leite materno e do leite de vaca fazem com que o esvaziamento gástrico seja mais rápido após ingestão do primeiro. Esta rapidez do esvaziamento gástrico pode estar associada ao esvaziamento da vesícula biliar, também mais rápido. O objetivo do trabalho foi determinar se há diferença na velocidade de esvaziamento da vesícula biliar, por método ultra-sonográfico, após ingestão de leite materno e leite de vaca. Estudamos 47 crianças menores de dois anos, 22 após uma refeição com leite materno e 25 após uma refeição com leite de vaca. A vesícula biliar foi medida após um período de quatro a seis horas de jejum e uma hora após uma refeição (leite materno ou leite de vaca, e a contração da vesícula biliar foi avaliada, em porcentagem, pela diferença de volume da vesícula biliar entre as duas medidas e expressa em porcentagem do volume inicial. As medianas das porcentagens do volume inicial para as crianças alimentadas com leite materno e leite de vaca foram, respectivamente, 92,25% e 53,8%, diferença estatisticamente significativa. Portanto, a contração da vesícula biliar após uma refeição com leite de vaca é muito mais lenta do que aquela após uma refeição com leite materno.Breast milk and cow's milk differ in multiple characteristics that account for a faster gastric emptying time after breast feeding. This faster gastric emptying may be associated with a faster gallbladder emptying. Our aim was to compare gallbladder contraction after breast milk meal and cow's milk meal using ultrasound examination. We studied 22 infants after a breast milk meal and 25 infants after a cow's milk meal. Gallbladder volume was measured after a 4-6 hours fasting and one hour after the meal (breast milk or cow's milk. Gallbladder contractility was calculated by determining the difference between gallbladder volume one hour after the meal and the fasting volume, and expressed as a

  8. Antígona y la muerte

    OpenAIRE

    Pérez Alcolea, Simona Micaela

    2012-01-01

    La ponencia analiza la muerte de Antígona en la obra de Sófocles. Se propone que su suicidio es un acto consciente de voluntad preanunciado a lo largo de toda la obra y no una medida desesperada. Con ese fin se exploran las posibles motivaciones de Antígona para poner fin a su vida. En el análisis se proponen tres respuestas (no necesariamente excluyentes): -Antígona responde a la ética homérica. Está en lucha con Creón, y su suicidio es su golpe de gracia al poder del rey. -Antígona...

  9. Ant-plant symbioses: Stalking the chuyachaqui.

    Science.gov (United States)

    Davidson, D W; McKey, D

    1993-09-01

    According to Quechua-speaking peoples, orchard-like stands ('Supay Chacras') of two Amazonian ant-plant species are cultivated by the devil, or 'Chuyachaqui'. These "devil gardens" offer extreme examples of specializations that have evolved repeatedly in ant-plant associations. Numerous investigations are beginning to disclose the identity of the Chuyachaqui - the forces behind evolutionary specialization in ant-plant symbioses. These developments have important implications for our understanding of modes of coevolution in symbiotic mutualism, remarkable convergent similarities in the form of ant-plant symbioses on different continents, and pronounced intercontinental differences in the diversity and taxonomic composition of associates. Copyright © 1993. Published by Elsevier Ltd.

  10. From Ant Trails to Pedestrian Dynamics

    Directory of Open Access Journals (Sweden)

    Andreas Schadschneider

    2003-01-01

    Full Text Available This paper presents a model for the simulation of pedestrian dynamics inspired by the behaviour of ants in ant trails. Ants communicate by producing a pheromone that can be smelled by other ants. In this model, pedestrians produce a virtual pheromone that influences the motion of others. In this way all interactions are strictly local, and so even large crowds can be simulated very efficiently. Nevertheless, the model is able to reproduce the collective effects observed empirically, eg the formation of lanes in counterflow. As an application, we reproduce a surprising result found in experiments of evacuation from an aircraft.

  11. Microorganisms transported by ants induce changes in floral nectar composition of an ant-pollinated plant.

    Science.gov (United States)

    de Vega, Clara; Herrera, Carlos M

    2013-04-01

    Interactions between plants and ants abound in nature and have significant consequences for ecosystem functioning. Recently, it has been suggested that nectar-foraging ants transport microorganisms to flowers; more specifically, they transport yeasts, which can potentially consume sugars and alter nectar composition. Therefore, ants could indirectly change nectar sugar profile, an important floral feature involved in the plant-pollinator mutualism. But this novel role for ants has never been tested. We here investigate the effects of nectarivorous ants and their associated yeasts on the floral nectar sugar composition of an ant-pollinated plant. Differences in the nectar sugar composition of ant-excluded and ant-visited flowers were examined in 278 samples by using high-performance liquid-chromatography. The importance of the genetic identity and density of ant-transported basidiomycetous and ascomycetous yeasts on the variation of nectar traits was also evaluated. Ant visitation had significant effects on nectar sugar composition. The nectar of ant-visited flowers contained significantly more fructose, more glucose, and less sucrose than the nectar of ant-excluded flowers, but these effects were context dependent. Nectar changes were correlated with the density of yeast cells in nectar. The magnitude of the effects of ant-transported ascomycetes was much higher than that of basiodiomycetes. Ants and their associated yeasts induce changes in nectar sugar traits, reducing the chemical control of the plant over this important floral trait. The potential relevance of this new role for ants as indirect nectar modifiers is a rich topic for future research into the ecology of ant-flower interactions.

  12. Pollination and facultative ant-association in the African leopard ...

    African Journals Online (AJOL)

    The role of extra-floral nectar appears to be recruitment of foraging ants to tend the flowers resulting in a facultative ant-association between the orchid and gregarious ants. Four different ant species were found to forage on A. africana's inflorescences. Ant-tended inflorescences suffered significantly less damage by insects.

  13. Michael Jackson antes del caos

    OpenAIRE

    Juan Luciano Nieves

    2015-01-01

    Michael Jackson es un buen ejemplo de cómo utilizar las relaciones públicas para realizar o manipular la imagen de un producto a través de los medios de comunicación. Este ensayo pretende analizar los eventos que tuvieron lugar antes de que el cantante fuera acusado de abuso sexual contra un menor. Dichos eventos formaron parte de un plan muy bien delineado para disminuir los efectos de la inminente crisis que se acercaba. Este trabajo combina la crítica retórica de temas de fantasía con teor...

  14. Viaje Antártico

    OpenAIRE

    Lasa, Gorka

    2017-01-01

    Ah, qué grandiosa sensación esta de poder caminar por los eternos hielos y dejar que mi vista se pierda en el horizonte crepuscular de esta desolada región! Aquellas solitarias islas, lamentos blancos en la distancia, aquellos azules glaciares llorando su neblina de frío y siglos. Al llamado lejano, mi alma se ve arrastrada por los vientos australes. Mítico ensueño que genera en mi imaginación el gran continente antártico. Belleza misteriosa e intimidante de la vastedad casi mágica que envuel...

  15. Foliar uptake of nitrogen from ant fecal droplets: an overlooked service to ant plants

    DEFF Research Database (Denmark)

    Pinkalski, Christian Alexander Stidsen; Jensen, Karl-Martin Vagn; Damgaard, Christian Frølund

    2018-01-01

    and subsequently deposited fecal droplets on the seedlings, coffee leaves showed increased levels of 15N and total N compared to control plants without ants. This was evident for both exposed leaves and leaves covered in plastic bags (i.e. not directly exposed to ants). Thus, N from ant excretions was absorbed...

  16. Visible Leading: Principal Academy Connects and Empowers Principals

    Science.gov (United States)

    Hindman, Jennifer; Rozzelle, Jan; Ball, Rachel; Fahey, John

    2015-01-01

    The School-University Research Network (SURN) Principal Academy at the College of William & Mary in Williamsburg, Virginia, has a mission to build a leadership development program that increases principals' instructional knowledge and develops mentor principals to sustain the program. The academy is designed to connect and empower principals…

  17. Polyacrylamide hydrogels: an effective tool for delivering liquid baits to pest ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Buczkowski, Grzegorz; Roper, Elray; Chin, Darren

    2014-04-01

    Ant management in urban and natural areas often relies on toxic baits. Liquid baits are highly attractive to pest ants because they mimic natural food sources such as honeydew and nectar, the principal dietary components of many ants. However, liquid bait use has been limited owing to the lack of bait dispensers that are effective, inexpensive, and easy to service. The current study evaluated the potential of water-storing crystals (polyacrylamide spheres) to effectively deliver liquid thiamethoxam baits to laboratory colonies of Argentine ants, Linepithema humile Mayr. Results of laboratory trials show that bait crystals saturated in 25% sucrose solution containing 0.007% thiamethoxam are highly attractive to Argentine ants and highly effective against all castes and life stages, including workers, queens, and brood. Fresh bait crystals were highly effective and required approximately 2 d to kill all workers and approximately 6 d to achieve complete mortality in queens and brood. Results of bait aging tests show that the crystals lose approximately 70% of moisture in 8 h and the duration of outdoor exposure has a significant effect on moisture loss and subsequently bait acceptance and bait efficacy. A gradual decrease in mortality was observed for all castes and life stages as bait age increased. In general, fresh baits and those aged for ants that obtain thiamethoxam by feeding on bait crystals effectively transfer it to untreated recipient ants. The level of secondary mortality depended on the donor:recipient ratio, with approximately 40% recipient worker mortality with the 1:5 ratio and 15% recipient worker mortality with 1:10 or 1:20 ratios. However, no queens died in any transfer tests, suggesting that multiple feedings from multiple donors may be necessary to produce queen mortality. The results of the transfer tests demonstrate the role of trophallaxis in the distribution of thiamethoxam and confirm that thiamethoxam is effectively transferred in Argentine

  18. The evolution of genome size in ants

    Directory of Open Access Journals (Sweden)

    Spagna Joseph C

    2008-02-01

    Full Text Available Abstract Background Despite the economic and ecological importance of ants, genomic tools for this family (Formicidae remain woefully scarce. Knowledge of genome size, for example, is a useful and necessary prerequisite for the development of many genomic resources, yet it has been reported for only one ant species (Solenopsis invicta, and the two published estimates for this species differ by 146.7 Mb (0.15 pg. Results Here, we report the genome size for 40 species of ants distributed across 10 of the 20 currently recognized subfamilies, thus making Formicidae the 4th most surveyed insect family and elevating the Hymenoptera to the 5th most surveyed insect order. Our analysis spans much of the ant phylogeny, from the less derived Amblyoponinae and Ponerinae to the more derived Myrmicinae, Formicinae and Dolichoderinae. We include a number of interesting and important taxa, including the invasive Argentine ant (Linepithema humile, Neotropical army ants (genera Eciton and Labidus, trapjaw ants (Odontomachus, fungus-growing ants (Apterostigma, Atta and Sericomyrmex, harvester ants (Messor, Pheidole and Pogonomyrmex, carpenter ants (Camponotus, a fire ant (Solenopsis, and a bulldog ant (Myrmecia. Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family. Moreover, our data suggest that two whole-genome duplications may have occurred in the ancestors of the modern Ectatomma and Apterostigma. Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship. Conclusion This is the first analysis of genome size in ants (Formicidae and the first across multiple species of social insects. We show that genome size is a variable trait that can evolve gradually over long time spans, as well as rapidly, through processes that may

  19. Hybrid chaotic ant swarm optimization

    International Nuclear Information System (INIS)

    Li Yuying; Wen Qiaoyan; Li Lixiang; Peng Haipeng

    2009-01-01

    Chaotic ant swarm optimization (CASO) is a powerful chaos search algorithm that is used to find the global optimum solution in search space. However, the CASO algorithm has some disadvantages, such as lower solution precision and longer computational time, when solving complex optimization problems. To resolve these problems, an improved CASO, called hybrid chaotic swarm optimization (HCASO), is proposed in this paper. The new algorithm introduces preselection operator and discrete recombination operator into the CASO; meanwhile it replaces the best position found by own and its neighbors' ants with the best position found by preselection operator and discrete recombination operator in evolution equation. Through testing five benchmark functions with large dimensionality, the experimental results show the new method enhances the solution accuracy and stability greatly, as well as reduces the computational time and computer memory significantly when compared to the CASO. In addition, we observe the results can become better with swarm size increasing from the sensitivity study to swarm size. And we gain some relations between problem dimensions and swam size according to scalability study.

  20. Principals' Salaries, 2007-2008

    Science.gov (United States)

    Cooke, Willa D.; Licciardi, Chris

    2008-01-01

    How do salaries of elementary and middle school principals compare with those of other administrators and classroom teachers? Are increases in salaries of principals keeping pace with increases in salaries of classroom teachers? And how have principals' salaries fared over the years when the cost of living is taken into account? There are reliable…

  1. Principals Who Think Like Teachers

    Science.gov (United States)

    Fahey, Kevin

    2013-01-01

    Being a principal is a complex job, requiring quick, on-the-job learning. But many principals already have deep experience in a role at the very essence of the principalship. They know how to teach. In interviews with principals, Fahey and his colleagues learned that thinking like a teacher was key to their work. Part of thinking the way a teacher…

  2. School Principals' Emotional Coping Process

    Science.gov (United States)

    Poirel, Emmanuel; Yvon, Frédéric

    2014-01-01

    The present study examines the emotional coping of school principals in Quebec. Emotional coping was measured by stimulated recall; six principals were filmed during a working day and presented a week later with their video showing stressful encounters. The results show that school principals experience anger because of reproaches from staff…

  3. Legal Problems of the Principal.

    Science.gov (United States)

    Stern, Ralph D.; And Others

    The three talks included here treat aspects of the law--tort liability, student records, and the age of majority--as they relate to the principal. Specifically, the talk on torts deals with the consequences of principal negligence in the event of injuries to students. Assurance is given that a reasonable and prudent principal will have a minimum…

  4. RE Rooted in Principal's Biography

    NARCIS (Netherlands)

    ter Avest, Ina; Bakker, C.

    2017-01-01

    Critical incidents in the biography of principals appear to be steering in their innovative way of constructing InterReligious Education in their schools. In this contribution, the authors present the biographical narratives of 4 principals: 1 principal introducing interreligious education in a

  5. The Future of Principal Evaluation

    Science.gov (United States)

    Clifford, Matthew; Ross, Steven

    2012-01-01

    The need to improve the quality of principal evaluation systems is long overdue. Although states and districts generally require principal evaluations, research and experience tell that many state and district evaluations do not reflect current standards and practices for principals, and that evaluation is not systematically administered. When…

  6. The Biochemical Toxin Arsenal from Ant Venoms

    Directory of Open Access Journals (Sweden)

    Axel Touchard

    2016-01-01

    Full Text Available Ants (Formicidae represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents.

  7. Hey! A Fire Ant Stung Me!

    Science.gov (United States)

    ... Videos for Educators Search English Español Hey! A Fire Ant Stung Me! KidsHealth / For Kids / Hey! A ... Me picó una roja o colorada! What's a Fire Ant? There are many different types of fire ...

  8. The Biochemical Toxin Arsenal from Ant Venoms

    Science.gov (United States)

    Touchard, Axel; Aili, Samira R.; Fox, Eduardo Gonçalves Paterson; Escoubas, Pierre; Orivel, Jérôme; Nicholson, Graham M.; Dejean, Alain

    2016-01-01

    Ants (Formicidae) represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents. PMID:26805882

  9. Ant aggression and evolutionary stability in plant-ant and plant-pollinator mutualistic interactions.

    Science.gov (United States)

    Oña, L; Lachmann, M

    2011-03-01

    Mutualistic partners derive a benefit from their interaction, but this benefit can come at a cost. This is the case for plant-ant and plant-pollinator mutualistic associations. In exchange for protection from herbivores provided by the resident ants, plants supply various kinds of resources or nests to the ants. Most ant-myrmecophyte mutualisms are horizontally transmitted, and therefore, partners share an interest in growth but not in reproduction. This lack of alignment in fitness interests between plants and ants drives a conflict between them: ants can attack pollinators that cross-fertilize the host plants. Using a mathematical model, we define a threshold in ant aggressiveness determining pollinator survival or elimination on the host plant. In our model we observed that, all else being equal, facultative interactions result in pollinator extinction for lower levels of ant aggressiveness than obligatory interactions. We propose that the capacity to discriminate pollinators from herbivores should not often evolve in ants, and when it does it will be when the plants exhibit limited dispersal in an environment that is not seed saturated so that each seed produced can effectively generate a new offspring or if ants acquire an extra benefit from pollination (e.g. if ants eat fruit). We suggest specific mutualism examples where these hypotheses can be tested empirically. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  10. AntStar: Enhancing Optimization Problems by Integrating an Ant System and A⁎ Algorithm

    Directory of Open Access Journals (Sweden)

    Mohammed Faisal

    2016-01-01

    Full Text Available Recently, nature-inspired techniques have become valuable to many intelligent systems in different fields of technology and science. Among these techniques, Ant Systems (AS have become a valuable technique for intelligent systems in different fields. AS is a computational system inspired by the foraging behavior of ants and intended to solve practical optimization problems. In this paper, we introduce the AntStar algorithm, which is swarm intelligence based. AntStar enhances the optimization and performance of an AS by integrating the AS and A⁎ algorithm. Applying the AntStar algorithm to the single-source shortest-path problem has been done to ensure the efficiency of the proposed AntStar algorithm. The experimental result of the proposed algorithm illustrated the robustness and accuracy of the AntStar algorithm.

  11. Cryptococcus neoformans carried by Odontomachus bauri ants

    Directory of Open Access Journals (Sweden)

    Mariana Santos de Jesus

    2012-06-01

    Full Text Available Cryptococcus neoformans is the most common causative agent of cryptococcosis worldwide. Although this fungus has been isolated from a variety of organic substrates, several studies suggest that hollow trees constitute an important natural niche for C. neoformans. A previously surveyed hollow of a living pink shower tree (Cassia grandis positive for C. neoformans in the city of Rio de Janeiro, Brazil, was chosen for further investigation. Odontomachus bauri ants (trap-jaw ants found inside the hollow were collected for evaluation as possible carriers of Cryptococcus spp. Two out of 10 ants were found to carry phenoloxidase-positive colonies identified as C. neoformans molecular types VNI and VNII. The ants may have acted as a mechanical vector of C. neoformans and possibly contributed to the dispersal of the fungi from one substrate to another. To the best of our knowledge, this is the first report on the association of C. neoformans with ants of the genus Odontomachus.

  12. Recurrence analysis of ant activity patterns.

    Directory of Open Access Journals (Sweden)

    Felipe Marcel Neves

    Full Text Available In this study, we used recurrence quantification analysis (RQA and recurrence plots (RPs to compare the movement activity of individual workers of three ant species, as well as a gregarious beetle species. RQA and RPs quantify the number and duration of recurrences of a dynamical system, including a detailed quantification of signals that could be stochastic, deterministic, or both. First, we found substantial differences between the activity dynamics of beetles and ants, with the results suggesting that the beetles have quasi-periodic dynamics and the ants do not. Second, workers from different ant species varied with respect to their dynamics, presenting degrees of predictability as well as stochastic signals. Finally, differences were found among minor and major caste of the same (dimorphic ant species. Our results underscore the potential of RQA and RPs in the analysis of complex behavioral patterns, as well as in general inferences on animal behavior and other biological phenomena.

  13. Ants defend aphids against lethal disease

    Science.gov (United States)

    Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

    2010-01-01

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  14. Principal stratification in causal inference.

    Science.gov (United States)

    Frangakis, Constantine E; Rubin, Donald B

    2002-03-01

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

  15. Persistence of pollination mutualisms in the presence of ants.

    Science.gov (United States)

    Wang, Yuanshi; Wang, Shikun

    2015-01-01

    This paper considers plant-pollinator-ant systems in which the plant-pollinator interaction is mutualistic but ants have both positive and negative effects on plants. The ants also interfere with pollinators by preventing them from accessing plants. While a Beddington-DeAngelis (BD) formula can describe the plant-pollinator interaction, the formula is extended in this paper to characterize the pollination mutualism under the ant interference. Then, a plant-pollinator-ant system with the extended BD functional response is discussed, and global dynamics of the model demonstrate the mechanisms by which pollination mutualism can persist in the presence of ants. When the ant interference is strong, it can result in extinction of pollinators. Moreover, if the ants depend on pollination mutualism for survival, the strong interference could drive pollinators into extinction, which consequently lead to extinction of the ants themselves. When the ant interference is weak, a cooperation between plant-ant and plant-pollinator mutualisms could occur, which promotes survival of both ants and pollinators, especially in the case that ants (respectively, pollinators) cannot survive in the absence of pollinators (respectively, ants). Even when the level of ant interference remains invariant, varying ants' negative effect on plants can result in survival/extinction of both ants and pollinators. Therefore, our results provide an explanation for the persistence of pollination mutualism when there exist ants.

  16. Le principe roman

    CERN Document Server

    Ferrari, Jérôme

    2015-01-01

    Fasciné par la figure du physicien allemand Werner Heisenberg (1901-1976), fondateur de la mécanique quantique, inventeur du célèbre "principe d'incertitude" et Prix Nobel de physique en 1932, un jeune aspirant-philosophe désenchanté s'efforce, à l'aube du XXIe siècle, de considérer l'incomplétude de sa propre existence à l'aune des travaux et de la destinée de cet exceptionnel homme de sciences qui incarne pour lui la rencontre du langage scientifique et de la poésie, lesquels, chacun à leur manière, en ouvrant la voie au scandale de l'inédit, dessillent les yeux sur le monde pour en révéler la mystérieuse beauté que ne cessent de confisquer le matérialisme à l'œuvre dans l'Histoire des hommes.

  17. Principal oscillation patterns

    International Nuclear Information System (INIS)

    Storch, H. von; Buerger, G.; Storch, J.S. von

    1993-01-01

    The Principal Oscillation Pattern (POP) analysis is a technique which is used to simultaneously infer the characteristic patterns and time scales of a vector time series. The POPs may be seen as the normal modes of a linearized system whose system matrix is estimated from data. The concept of POP analysis is reviewed. Examples are used to illustrate the potential of the POP technique. The best defined POPs of tropospheric day-to-day variability coincide with the most unstable modes derived from linearized theory. POPs can be derived even from a space-time subset of data. POPs are successful in identifying two independent modes with similar time scales in the same data set. The POP method can also produce forecasts which may potentially be used as a reference for other forecast models. The conventional POP analysis technique has been generalized in various ways. In the cyclostationary POP analysis, the estimated system matrix is allowed to vary deterministically with an externally forced cycle. In the complex POP analysis not only the state of the system but also its ''momentum'' is modeled. Associated correlation patterns are a useful tool to describe the appearance of a signal previously identified by a POP analysis in other parameters. (orig.)

  18. Michael Jackson antes del caos

    Directory of Open Access Journals (Sweden)

    Juan Luciano Nieves

    2015-01-01

    Full Text Available Michael Jackson es un buen ejemplo de cómo utilizar las relaciones públicas para realizar o manipular la imagen de un producto a través de los medios de comunicación. Este ensayo pretende analizar los eventos que tuvieron lugar antes de que el cantante fuera acusado de abuso sexual contra un menor. Dichos eventos formaron parte de un plan muy bien delineado para disminuir los efectos de la inminente crisis que se acercaba. Este trabajo combina la crítica retórica de temas de fantasía con teoría de comunicación.

  19. Individual Recognition in Ant Queens

    DEFF Research Database (Denmark)

    D'Ettorre, Patrizia; Heinze, Jürgen

    2005-01-01

    Personal relationships are the cornerstone of vertebrate societies, but insect societies are either too large for individual recognition, or their members were assumed to lack the necessary cognitive abilities 1 and 2 . This paradigm has been challenged by the recent discovery that paper wasps...... recognize each other's unique facial color patterns [3] . Individual recognition is advantageous when dominance hierarchies control the partitioning of work and reproduction 2 and 4 . Here, we show that unrelated founding queens of the ant Pachycondyla villosa use chemical cues to recognize each other...... individually. Aggression was significantly lower in pairs of queens that had previously interacted than in pairs with similar social history but no experience with one another. Moreover, subordinates discriminated familiar and unfamiliar dominants in choice experiments in which physical contact, but not odor...

  20. FDTD-ANT User Manual

    Science.gov (United States)

    Zimmerman, Martin L.

    1995-01-01

    This manual explains the theory and operation of the finite-difference time domain code FDTD-ANT developed by Analex Corporation at the NASA Lewis Research Center in Cleveland, Ohio. This code can be used for solving electromagnetic problems that are electrically small or medium (on the order of 1 to 50 cubic wavelengths). Calculated parameters include transmission line impedance, relative effective permittivity, antenna input impedance, and far-field patterns in both the time and frequency domains. The maximum problem size may be adjusted according to the computer used. This code has been run on the DEC VAX and 486 PC's and on workstations such as the Sun Sparc and the IBM RS/6000.

  1. Use of fully covered self-expanding metal stents for the management of benign biliary conditions Utilización de prótesis metálicas autoexpandibles totalmente recubiertas en procesos biliares benignos

    Directory of Open Access Journals (Sweden)

    J. García-Cano

    2010-09-01

    Full Text Available Background and aim: biliary self-expanding metal stents (SEMS have the advantage of being inserted undeployed with very small sizes and provide, when fully opened, large diameters for biliary drainage. However, their use in benign conditions has been very limited, mainly because of difficulty in their extraction. We present our initial experience with a fully covered SEMS (Wallflex for the management of benign problems of the bile duct. Patients and methods: in a prospective study, stents of 8 mm in diameter and 4, 6 or 8 cm long were inserted by means of ERCP. These SEMS were chosen when according to medical judgement it was thought that diameters greater than 10 French (3.3 mm were needed for proper biliary drainage. Stents were extracted also endoscopically, several months later when deemed clinically appropriate. Results: twenty biliary SEMS were inserted. Reasons for insertion were: large intrahepatic biliary fistula after hydatid cyst surgery (1, perforation of the papillary area following endoscopic sphincterotomy (2, coaxial insertion to achieve patency in obstructed uncovered stents inserted in benign conditions (3, benign strictures (7, multiple and large common bile duct stones that could not be extracted because of tapering and stricturing of the distal common bile duct (7. In all cases, successful biliary drainage was achieved and there were no complications from insertion. Stents were easily extracted after a mean time of 132 days (36-270 in place. Complete resolution of biliary problems was obtained in 14 patients (70%. Conclusions: in our initial experience, the fully covered Wallflex biliary stent was removed without any complication after being in place in the common bile duct for a mean time of over four months. Therefore, it could be used in the management of benign biliary conditions.Introducción y objetivo: las prótesis metálicas autoexpandibles biliares (PMAB tienen la ventaja de introducirse plegadas con calibres muy

  2. A preliminary checklist of the ants (Hymenoptera, Formicidae of Andorra

    Directory of Open Access Journals (Sweden)

    Abel Bernadou

    2013-03-01

    Full Text Available Within the last decade, checklists of the ant fauna of several European countries have been published or updated. Nevertheless, no ant checklists have hitherto been published for the principality of Andorra, a small landlocked country located in the eastern part of the Pyrenees. This work presents a critical list of the ant species of Andorra based on a review of the literature and on the biological material we collected during several field campaigns conducted in Andorra since the year 2005. Seventy-five species belonging to 21 genera of Formicidae were recorded. Nine species were recorded for the first time in Andorra: Aphaenogaster gibbosa (Latreille, 1798, Camponotus lateralis (Olivier, 1792, Camponotus piceus (Leach, 1825, Formica exsecta Nylander, 1846, Lasius piliferus Seifert, 1992, Tapinoma madeirense Forel, 1895, Temnothorax lichtensteini (Bondroit, 1918, Temnothorax niger (Forel, 1894, Temnothorax nigriceps (Mayr, 1855. The most speciose genera were Formica Linnaeus, 1758 and Temnothorax Forel, 1890 with 14 and 12 species, respectively. The ant fauna of Andorra is mostly dominated by Central European species (some are typical cold climate specialists; however species belonging to the Mediterranean ant fauna were also found. This can be explained by the particular geographic situation of Andorra which is characterized by a high mountain Mediterranean climate.

  3. Giant ants and their shape: revealing relationships in the genus Titanomyrma with geometric morphometrics

    Directory of Open Access Journals (Sweden)

    Julian Katzke

    2018-01-01

    Full Text Available Shape is a natural phenomenon inherent to many different lifeforms. A modern technique to analyse shape is geometric morphometrics (GM, which offers a whole range of methods concerning the pure shape of an object. The results from these methods have provided new insights into biological problems and have become especially useful in the fields of entomology and palaeontology. Despite the conspicuous successes in other hymenopteran groups, GM analysis of wings and fossil wings of Formicidae has been neglected. Here we tested if landmarks defining the wing shape of fossil ants that belong to the genus Titanomyrma are reliable and if this technique is able to expose relationships among different groups of the largest Hymenoptera that ever lived. This study comprises 402 wings from 362 ants that were analysed and assigned with the GM methods linear discriminant function analysis, principal component analysis, canonical variate analysis, and regression. The giant ant genus Titanomyrma and the parataxon Formicium have different representatives that are all very similar but these modern methods were able to distinguish giant ant types even to the level of the sex. Thirty-five giant ant specimens from the Eckfeld Maar were significantly differentiable from a collection of Messel specimens that consisted of 187 Titanomyrma gigantea females and 42 T. gigantea males, and from 74 Titanomyrma simillima females and 21 T. simillima males. Out of the 324 Messel ants, 127 are newly assigned to a species and 223 giant ants are newly assigned to sex with GM analysis. All specimens from Messel fit to the two species. Moreover, shape affinities of these groups and the species Formicium brodiei, Formicium mirabile, and Formicium berryi, which are known only from wings, were investigated. T. gigantea stands out with a possible female relative in one of the Eckfeld specimens whereas the other groups show similar shape patterns that are possibly plesiomorphic. Formicidae

  4. Giant ants and their shape: revealing relationships in the genus Titanomyrma with geometric morphometrics.

    Science.gov (United States)

    Katzke, Julian; Barden, Phillip; Dehon, Manuel; Michez, Denis; Wappler, Torsten

    2018-01-01

    Shape is a natural phenomenon inherent to many different lifeforms. A modern technique to analyse shape is geometric morphometrics (GM), which offers a whole range of methods concerning the pure shape of an object. The results from these methods have provided new insights into biological problems and have become especially useful in the fields of entomology and palaeontology. Despite the conspicuous successes in other hymenopteran groups, GM analysis of wings and fossil wings of Formicidae has been neglected. Here we tested if landmarks defining the wing shape of fossil ants that belong to the genus Titanomyrma are reliable and if this technique is able to expose relationships among different groups of the largest Hymenoptera that ever lived. This study comprises 402 wings from 362 ants that were analysed and assigned with the GM methods linear discriminant function analysis, principal component analysis, canonical variate analysis, and regression. The giant ant genus Titanomyrma and the parataxon Formicium have different representatives that are all very similar but these modern methods were able to distinguish giant ant types even to the level of the sex. Thirty-five giant ant specimens from the Eckfeld Maar were significantly differentiable from a collection of Messel specimens that consisted of 187 Titanomyrma gigantea females and 42 T. gigantea males, and from 74 Titanomyrma simillima females and 21 T. simillima males. Out of the 324 Messel ants, 127 are newly assigned to a species and 223 giant ants are newly assigned to sex with GM analysis. All specimens from Messel fit to the two species. Moreover, shape affinities of these groups and the species Formicium brodiei , Formicium mirabile , and Formicium berryi , which are known only from wings, were investigated. T. gigantea stands out with a possible female relative in one of the Eckfeld specimens whereas the other groups show similar shape patterns that are possibly plesiomorphic. Formicidae are one of the

  5. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant-plant mutualism.

    Science.gov (United States)

    Pringle, Elizabeth G

    2014-06-22

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant-plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output.

  6. Collective search by ants in microgravity

    Directory of Open Access Journals (Sweden)

    Stefanie M. Countryman

    2015-03-01

    Full Text Available The problem of collective search is a tradeoff between searching thoroughly and covering as much area as possible. This tradeoff depends on the density of searchers. Solutions to the problem of collective search are currently of much interest in robotics and in the study of distributed algorithms, for example to design ways that without central control robots can use local information to perform search and rescue operations. Ant colonies operate without central control. Because they can perceive only local, mostly chemical and tactile cues, they must search collectively to find resources and to monitor the colony's environment. Examining how ants in diverse environments solve the problem of collective search can elucidate how evolution has led to diverse forms of collective behavior. An experiment on the International Space Station in January 2014 examined how ants (Tetramorium caespitum perform collective search in microgravity. In the ISS experiment, the ants explored a small arena in which a barrier was lowered to increase the area and thus lower ant density. In microgravity, relative to ground controls, ants explored the area less thoroughly and took more convoluted paths. It appears that the difficulty of holding on to the surface interfered with the ants’ ability to search collectively. Ants frequently lost contact with the surface, but showed a remarkable ability to regain contact with the surface.

  7. Gallstones in children with sickle cell disease followed up at a Brazilian hematology center Litíase biliar em crianças com doença falciforme acompanhadas em um centro de hematologia no Brasil

    Directory of Open Access Journals (Sweden)

    Ana Paula dos Santos Gumiero

    2008-12-01

    considered in symptomatic patients. In asymptomatic patients, conservative management seems to be the better choice.RACIONAL: A doença falciforme causa hemólise crônica e acelerada que é reconhecida como fator de risco para desenvolvimento de colelitíase. Essa complicação pode ocorrer em mais de 50% da população adulta com doença falciforme. A colecistectomia é a conduta consensual para pacientes sintomáticos, mas nos assintomáticos a sua indicação é controversa. OBJETIVOS: Verificar a prevalência de colelitíase em pacientes com doença falciforme e descrever a conduta tomada em caso de diagnóstico da complicação, numa corte de pacientes seguidos num centro terciário de hematologia pediátrica. MÉTODOS: Neste estudo descritivo e retrospectivo, foram revistos prontuários de 225 pacientes e os dados relacionados à evolução clínica desses indivíduos foram registrados. RESULTADOS: A freqüência cumulativa de colelitíase foi de 45%, sendo que metade deles não apresentava quaisquer sintomas. As médias de idade ao diagnóstico de colelitíase e seu tratamento cirúrgico foram, respectivamente, 12,5 anos (desvio padrão = 5 anos e 14 anos (desvio padrão = 5,4 anos. A prevalência de colelitíase foi maior nos pacientes com doença SS (homozigotos e Sb (heterozigotos talassemia, comparados aos pacientes com doença falciforme. Entre os pacientes sintomáticos (50%, a dor abdominal inespecífica foi o único sintoma ou o sintoma predominante. Entre pacientes que realizaram colecistectomia (n = 44, 39 tiveram melhora ou resolução de seus sintomas após o procedimento. Em 7 anos (desvio padrão = 4,8 anos de seguimento clínico dos pacientes assintomáticos e não tratados cirurgicamente, verificou-se que nenhuma criança apresentou complicações relacionadas à colelitíase. CONCLUSÕES: A freqüência de colelitíase na população estudada foi de 45%. Um terço dos pacientes foram diagnosticados antes dos 10 anos de idade. Pacientes com fen

  8. Ant-lepidopteran associations along African forest edges

    Science.gov (United States)

    Dejean, Alain; Azémar, Frédéric; Libert, Michel; Compin, Arthur; Hérault, Bruno; Orivel, Jérôme; Bouyer, Thierry; Corbara, Bruno

    2017-02-01

    Working along forest edges, we aimed to determine how some caterpillars can co-exist with territorially dominant arboreal ants (TDAAs) in tropical Africa. We recorded caterpillars from 22 lepidopteran species living in the presence of five TDAA species. Among the defoliator and/or nectarivorous caterpillars that live on tree foliage, the Pyralidae and Nymphalidae use their silk to protect themselves from ant attacks. The Notodontidae and lycaenid Polyommatinae and Theclinae live in direct contact with ants; the Theclinae even reward ants with abundant secretions from their Newcomer gland. Lichen feeders (lycaenid; Poritiinae), protected by long bristles, also live among ants. Some lycaenid Miletinae caterpillars feed on ant-attended membracids, including in the shelters where the ants attend them; Lachnocnema caterpillars use their forelegs to obtain trophallaxis from their host ants. Caterpillars from other species live inside weaver ant nests. Those of the genus Euliphyra (Miletinae) feed on ant prey and brood and can obtain trophallaxis, while those from an Eberidae species only prey on host ant eggs. Eublemma albifascia (Erebidae) caterpillars use their thoracic legs to obtain trophallaxis and trophic eggs from ants. Through transfer bioassays of last instars, we noted that herbivorous caterpillars living in contact with ants were always accepted by alien conspecific ants; this is likely due to an intrinsic appeasing odor. Yet, caterpillars living in ant shelters or ant nests probably acquire cues from their host colonies because they were considered aliens and killed. We conclude that co-evolution with ants occurred similarly in the Heterocera and Rhopalocera.

  9. Pheromone disruption of Argentine ant trail integrity

    Science.gov (United States)

    Suckling, D.M.; Peck, R.W.; Manning, L.M.; Stringer, L.D.; Cappadonna, J.; El-Sayed, A. M.

    2008-01-01

    Disruption of Argentine ant trail following and reduced ability to forage (measured by bait location success) was achieved after presentation of an oversupply of trail pheromone, (Z)-9-hexadecenal. Experiments tested single pheromone point sources and dispersion of a formulation in small field plots. Ant walking behavior was recorded and digitized by using video tracking, before and after presentation of trail pheromone. Ants showed changes in three parameters within seconds of treatment: (1) Ants on trails normally showed a unimodal frequency distribution of walking track angles, but this pattern disappeared after presentation of the trail pheromone; (2) ants showed initial high trail integrity on a range of untreated substrates from painted walls to wooden or concrete floors, but this was significantly reduced following presentation of a point source of pheromone; (3) the number of ants in the pheromone-treated area increased over time, as recruitment apparently exceeded departures. To test trail disruption in small outdoor plots, the trail pheromone was formulated with carnuba wax-coated quartz laboratory sand (1 g quartz sand/0.2 g wax/1 mg pheromone). The pheromone formulation, with a half-life of 30 h, was applied by rotary spreader at four rates (0, 2.5, 7.5, and 25 mg pheromone/m2) to 1- and 4-m2 plots in Volcanoes National Park, Hawaii. Ant counts at bait cards in treated plots were significantly reduced compared to controls on the day of treatment, and there was a significant reduction in ant foraging for 2 days. These results show that trail pheromone disruption of Argentine ants is possible, but a much more durable formulation is needed before nest-level impacts can be expected. ?? 2008 Springer Science+Business Media, LLC.

  10. Susceptibilidade da mucosa gástrica à ação lesiva de um sal biliar em ratos chagásicos crônicos

    Directory of Open Access Journals (Sweden)

    Luiz Ernesto de Almeida Troncon

    1987-12-01

    Full Text Available Ratos inoculados previamente com a cepa Y do Trypanosoma cruzi (n = 15 e ratos-controles de mesma idade e sexo (n = 15 foram submetidos a estudo que consistiu no exame da mucosa gástrica após a exposição in vivo da mesma à solução acidificada de um sal biliar, o taurocolato de sódio (TC. Em 10 animais de cada grupo procedeu-se também à contagem dos neurônios do plexo mientérico do estômago e ao exame histopatológico dos corpos neuronais, feito em microscopia óptica convencional. Escores indicativos da gravidade das lesões produzidas pelo TC foram significativamente maiores (P < 0,002 nos ratos chagásicos que nos controles. A área erosada da mucosa gástrica, em % da área total da região glandular do estômago, foi significativamente maior (P0,10 entre os ratos chagásicos (1683,6 ± 449,7 n = 10 e os controles (1732,8 ± 401,1 n = 10. Não houve diferença qualitativa ao exame histopatológico dos corpos neuronais. Estes resultados indicam que, na doença de Chagas experimental crônica, a mucosa gástrica é mais sensível à ação lesiva do TC, o que sugere redução da citoproteção natural do estômago. Esta anormalidade não deve decorrer de alterações da inervação intrínseca que impliquem redução do número de neurônios intramurais do estômago, mas pode ser o resultado de alterações qualitativas não detectáveis à microscopia óptica.

  11. Íleo biliar:: complicación poco frecuente de la litiasis vesicular Biliary ileum:: an uncommon complication of vesicular lithiasis

    Directory of Open Access Journals (Sweden)

    Gabriel González Sosa

    2010-06-01

    Full Text Available Se presenta el caso de una paciente de 80 años de edad, con antecedentes de diabetes mellitus de tipo II, cardiopatía isquémica y obesidad exógena, que ingresó de urgencia, por presentar un cuadro de dolor abdominal, varios vómitos y distensión abdominal de 3 días de evolución. De forma secundaria presentó una deshidratación moderada. En la radiografía simple de abdomen se constataron signos radiológicos de oclusión intestinal, que corroboraron una ecografía abdominal y una tomografía axial computadorizada de abdomen. Se corrigió el desequilibrio hidroelectrolítico y se realizó una laparotomía exploradora, en la que se encontró un cálculo grande enclavado en el íleon terminal. Se realizó una enterolitotomía con enterorrafia y resolvió el cuadro oclusivo. A los 16 días del alta, la paciente reingresa con un cuadro similar y al reintervenirla se constató la presencia de otro cálculo y de una fístula colecistogástrica, que involucraba la vesícula biliar y el antro gástrico. Se reparó mediante colecistectomía y gastrorrafia. Al final del transoperatorio la paciente presentó un episodio de fibrilación ventricular, con bradicardia extrema, y finalmente un paro en asistolia. Fue reanimada, pero la situación no se revirtió y la paciente falleció.This the case of a female patient aged 80 with a history of type 2 diabetes mellitus, ischemic heart failure and a exogenous obesity urgently admitted due to abdominal pain, vomiting and abdominal distention of 3 days course. In abdominal simple radiograph radiological signs of intestinal occlusion were confirmed corroborated by abdominal echography and CAT. Hydroelectrolytic imbalance was corrected performing an exploration laparotomy observing the presence of large calculus located in terminal ileum. An enterolithotomy with enterorrhaphy and occlusive picture was resolved. At 16 from discharge, patient is re-admitted with a similar situation and at re

  12. Empleo del modelo animal en la formación en endoscopia diagnóstica y terapéutica de la vía biliar

    Directory of Open Access Journals (Sweden)

    J. Usón-Gargallo

    Full Text Available Objetivo. Mostrar nuestra experiencia en la formación en endoscopia terapéutica de la vía biliar en modelo animal. Materiales y métodos. Esta actividad formativa tiene una duración de 13 horas y comienza iniciando al alumno en las diferencias anatómicas de las especies que se emplean, la porcina y la canina, con respecto a la anatomía humana. Las prácticas consisten en habituar al endoscopista a la visión lateral del duodenoscopio; se realizan en un modelo porcino debido a que es más sencillo atravesar el esfínter pilórico, aunque no suele ser muy adecuado para la canulación de la papila duodenal. Tras superar la primera fase se utiliza el modelo canino, que permite adquirir las habilidades y destrezas propias de esta técnica. La evaluación de los resultados se realiza mediante una encuesta anónima. Resultados. El 76% de los alumnos confirma que ha avanzado mucho con este entrenamiento, un 18% regular y un 6% poco. El 75% considera que, tras realizar esta actividad de formación, se encontraría capacitado para llevar a cabo la técnica en su hospital. El 94% de los alumnos recomendaría esta actividad a sus compañeros. Conclusiones. El empleo del modelo animal en la formación en colangiopancreatografía retrógada endoscópica (CPRE permite la adquisición de habilidades básicas necesarias para la práctica, ya que posibilita la repetición de las maniobras y la tutela continuada. Consideramos que con esta metodología mixta se podría acortar la curva de aprendizaje de la CPRE y disminuiría la iatrogenia en las primeras fases.

  13. Portraits of Principal Practice: Time Allocation and School Principal Work

    Science.gov (United States)

    Sebastian, James; Camburn, Eric M.; Spillane, James P.

    2018-01-01

    Purpose: The purpose of this study was to examine how school principals in urban settings distributed their time working on critical school functions. We also examined who principals worked with and how their time allocation patterns varied by school contextual characteristics. Research Method/Approach: The study was conducted in an urban school…

  14. What do myrmecophagous geckos eat when ants are not available ...

    African Journals Online (AJOL)

    Like other Pristurus species, P. samhaensis on Samha and P. sokotranus on Socotra were highly myrmecophagous (76.7% and 38.6% ants, respectively). However, ants were absent from the diet of P. samhaensis on Darsa. In contrast to the rich native ant fauna of the other islands, only one ant species was reported for ...

  15. Ants as tools in sustainable agriculture

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2015-01-01

    1. With an expanding human population placing increasing pressure on the environment, agriculture needs sustainable production that can match conventional methods. Integrated pest management (IPM) is more sustainable, but not necessarily as efficient as conventional non-sustainable measures. 2...... in multiple crops. Their efficiency is comparable to chemical pesticides or higher, while at lower costs. They provide a rare example of documented efficient conservation biological control. 3. Weaver ants share beneficial traits with almost 13 000 other ant species and are unlikely to be unique...... of agricultural systems, this review emphasizes the potential of managing ants to achieve sustainable pest management solutions. The synthesis suggests future directions and may catalyse a research agenda on the utilization of ants, not only against arthropod pests, but also against weeds and plant diseases...

  16. Kunstikriitik Ants Juske sai doktoriks / Neeme Korv

    Index Scriptorium Estoniae

    Korv, Neeme, 1974-

    2003-01-01

    Tartu Kõrgema Kunstikooli rektor Ants Juske kaitses 7. veebruaril Tallinnas Kunstiakadeemias edukalt doktoriväitekirja, juhendajaks oli professor Boris Bernštein ning oponeerisid doktor Altti Kuusamo Soomest ja professor Peeter Tulviste

  17. Fungal enzymes in the attine ant symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    the more basal attine genera use substrates such as flowers, plant debris, small twigs, insect feces and insect carcasses. This diverse array of fungal substrates across the attine lineage implies that the symbiotic fungus needs different enzymes to break down the plant material that the ants provide...... or different efficiencies of enzyme function. Fungal enzymes that degrade plant cell walls may have functionally co-evolved with the ants in this scenario. We explore this hypothesis with direct measurements of enzyme activity in fungus gardens in 12 species across 8 genera spanning the entire phylogeny...... and diversity of life-styles within the attine clade. We find significant differences in enzyme activity between different genera and life-styles of the ants. How these findings relate to attine ant coevolution and crop optimization are discussed....

  18. School Principals' Sources of Knowledge

    Science.gov (United States)

    Perkins, Arland Early

    2014-01-01

    The purpose of this study was to determine what sources of professional knowledge are available to principals in 1 rural East Tennessee school district. Qualitative research methods were applied to gain an understanding of what sources of knowledge are used by school principals in 1 rural East Tennessee school district and the barriers they face…

  19. Innovation Management Perceptions of Principals

    Science.gov (United States)

    Bakir, Asli Agiroglu

    2016-01-01

    This study is aimed to determine the perceptions of principals about innovation management and to investigate whether there is a significant difference in this perception according to various parameters. In the study, descriptive research model is used and universe is consisted from principals who participated in "Acquiring Formation Course…

  20. What Do Effective Principals Do?

    Science.gov (United States)

    Protheroe, Nancy

    2011-01-01

    Much has been written during the past decade about the changing role of the principal and the shift in emphasis from manager to instructional leader. Anyone in education, and especially principals themselves, could develop a mental list of responsibilities that fit within each of these realms. But research makes it clear that both those aspects of…

  1. Time Management for New Principals

    Science.gov (United States)

    Ruder, Robert

    2008-01-01

    Becoming a principal is a milestone in an educator's professional life. The principalship is an opportunity to provide leadership that will afford students opportunities to thrive in a nurturing and supportive environment. Despite the continuously expanding demands of being a new principal, effective time management will enable an individual to be…

  2. Bureaucratic Control and Principal Role.

    Science.gov (United States)

    Bezdek, Robert; And Others

    The purposes of this study were to determine the manner in which the imposition of increased bureaucratic control over principals influenced their allocation of time to tasks and to investigate principals' perceptions of the changes in their roles brought about by this increased control. The specific bureaucratic control system whose effects were…

  3. Exotic ants (Hymenoptera, Formicidae) of Ohio

    OpenAIRE

    Ivanov,Kal

    2016-01-01

    The worldwide transfer of plants and animals outside their native ranges is an ever increasing problem for global biodiversity. Ants are no exception and many species have been transported to new locations often with profound negative impacts on local biota. The current study is based on data gathered since the publication of the “Ants of Ohio” in 2005. Here I expand on our knowledge of Ohio’s myrmecofauna by contributing new records, new distributional information and natural history notes. ...

  4. Improving Emergency Management by Modeling Ant Colonies

    Science.gov (United States)

    2015-03-01

    perform functions such as nursing the brood or maintaining the nest. The more mature workers will begin to travel outside the nest to perform foraging...small sized ants predominantly act in functional roles such as nurses or transport services within the nest. The larger sizes predominantly function...stages: the founding stage, the ergonomic stage, and the reproductive stage. The founding stage is marked by a queen ant successful mating and laying

  5. Extrafloral nectar fuels ant life in deserts

    OpenAIRE

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-01-01

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal dese...

  6. Chemically armed mercenary ants protect fungus-farming societies

    DEFF Research Database (Denmark)

    Adams, Rachelle Martha Marie; Liberti, Joanito; Illum, Anders A.

    2013-01-01

    guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit......The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated...... parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few...

  7. Toxic industrial deposit remediation by ant activity

    Science.gov (United States)

    Jilkova, Veronika; Frouz, Jan

    2016-04-01

    Toxic industrial deposits are often contaminated by heavy metals and the substrates have low pH values. In such systems, soil development is thus slowed down by high toxicity and acidic conditions which are unfavourable to soil fauna. Ants (Hymenoptera, Formicidae) are considered tolerant to heavy metal pollution and are known to increase organic matter content and microbial activity in their nests. Here, we focused on soil remediation caused by three ant species (Formica sanguinea, Lasius niger, and Tetramorium sp.) in an ore-washery sedimentation basin near Chvaletice (Czech Republic). Soil samples were taken from the centre of ant nests and from the nest surroundings (>3 m from nests). Samples were then analyzed for microbial activity and biomass and contents of organic matter and nutrients. As a result, ant species that most influenced soil properties was F. sanguinea as there were higher microbial activity and total nitrogen and ammonia contents in ant nests than in the surrounding soil. We expected such a result because F. sanguinea builds conspicuous large nests and is a carnivorous species that brings substantial amounts of nitrogen in insect prey to their nests. Effects of the other two ant species might be lower because of smaller nests and different feeding habits as they rely mainly on honeydew from aphids or on plant seeds that do not contain much nutrients.

  8. Congestion and communication in confined ant traffic

    Science.gov (United States)

    Gravish, Nick; Gold, Gregory; Zangwill, Andrew; Goodisman, Michael A. D.; Goldman, Daniel I.

    2014-03-01

    Many social animals move and communicate within confined spaces. In subterranean fire ants Solenopsis invicta, mobility within crowded nest tunnels is important for resource and information transport. Within confined tunnels, communication and traffic flow are at odds: trafficking ants communicate through tactile interactions while stopped, yet ants that stop to communicate impose physical obstacles on the traffic. We monitor the bi-directional flow of fire ant workers in laboratory tunnels of varied diameter D. The persistence time of communicating ant aggregations, τ, increases approximately linearly with the number of participating ants, n. The sensitivity of traffic flow increases as D decreases and diverges at a minimum diameter, Dc. A cellular automata model incorporating minimal traffic features--excluded volume and communication duration--reproduces features of the experiment. From the model we identify a competition between information transfer and the need to maintain jam-free traffic flow. We show that by balancing information transfer and traffic flow demands, an optimum group strategy exists which maximizes information throughput. We acknowledge funding from NSF PoLS #0957659 and #PHY-1205878.

  9. Fire ants perpetually rebuild sinking towers

    Science.gov (United States)

    Phonekeo, Sulisay; Mlot, Nathan; Monaenkova, Daria; Hu, David L.; Tovey, Craig

    2017-07-01

    In the aftermath of a flood, fire ants, Solenopsis invicta, cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers.

  10. Recurrence of hepatocellular carcinoma after liver transplantation presenting as anastomotic biliary stricture Presentación del carcinoma hepatocelular recurrente tras el trasplante de hígado en forma de estenosis biliar anastomótica

    Directory of Open Access Journals (Sweden)

    S. Y. Chen

    2008-07-01

    Full Text Available A 52-year-old man visited our hospital complaining of anorexia and fatigue two months after receiving orthotopic liver transplantation for hepatocellular carcinoma. A laboratory investigation demonstrated a clinical picture of obstructive jaundice. T-tube cholangiography showed biliary stricture over the anastomotic site. Percutaneous transluminal balloon dilatation and stenting was attempted but failed. Magnetic resonance cholangiography showed possible tumor recurrence over the site of the anastomotic biliary stricture. A biopsy sample was obtained via ultrasound-guided aspiration and histopathological study revealed inflammatory and fibrotic changes. With high suspicion of recurrence of the hepatocellular carcinoma, surgical exploration was performed and an intraoperative frozen section proved the recurrence. We thus diagnosed this case as a recurrence of hepatocellular carcinoma after liver transplantation. To our knowledge, there have been no previous reports of early tumor recurrence after liver transplantation being the cause of an anastomotic biliary stricture.Un varón de 52 años visitó nuestro hospital quejándose de anorexia y fatiga a los dos meses de haber recibido un trasplante hepático ortotópico a causa de un carcinoma hepatocelular. La analítica mostró un cuadro clínico de ictericia obstructiva. La colangiografía con tubo en T mostró una estenosis biliar sobre la anastomosis. Se intentó una dilatación transluminal percutánea con globo y colocación de endoprótesis, que fracasó. La colangiografía por resonancia magnética mostró una posible recurrencia tumoral sobre el lugar de la estenosis biliar anastomótica. Se extrajo una muestra de biopsia mediante aspiración bajo guía ecográfica y el estudio histopatológico mostró alteraciones inflamatorias y fibróticas. Al sospecharse la recurrencia del carcinoma hepatocelular, se realizó una exploración quirúrgica; un corte intraoperatorio congelado demostr

  11. MÉTODO DE INDUÇÃO DE CIRROSE BILIAR SECUNDÁRIA COM USO DE PRÓTESE DE SILICONE METHOD FOR THE EXPERIMENTAL INDUCTION OF SECUNDARY BILIARY CIRRHOSIS IN WISTAR RATS

    Directory of Open Access Journals (Sweden)

    A. A. L. de Araujo Lima

    2001-01-01

    Full Text Available O objetivo deste experimento foi o desenvolvimento de um modelo de obstrução do ducto biliar comum através da interposição de uma prótese de silicone extrínseca ao ducto com única ligadura sem secção. Desenvolveu-se um modelo experimental alternativo, em ratos Wistar, que provoca a interrupção do fluxo bílio-duodenal com resultado satisfatório, pois houve distorção da arquitetura hepática, caracterizada por fibrose e proliferação ductal além de indicadores bioquímicos da colestase.

  12. Cryptosporidiosis of the biliary tract mimicking pancreatic cancer in an AIDS patient Criptosporidiose do trato biliar simulando câncer do pâncreas em paciente com AIDS

    Directory of Open Access Journals (Sweden)

    Lenice do Rosário de Souza

    2004-03-01

    Full Text Available Diarrhea caused by Cryptosporidium sp is frequent in patients with AIDS, but involvement of other organs of the digestive tract is uncommon. We report a case of Cryptosporidium-associated obstruction of the biliary tract mimicking cancer of the head of the pancreas in a 43-year-old woman with AIDS.A diarréia causada pelo Cryptosporidium sp é muito freqüente em pacientes com AIDS, mas o envolvimento de outros órgãos do aparelho digestivo é incomum. Relata-se o caso de uma mulher de 43 anos, que tinha AIDS, que apresentava obstrução das vias biliares associada ao Cryptosporidium, simulando câncer da cabeça do pâncreas.

  13. Resultados del drenaje de la vía biliar por CPRE en pacientes con edad geriátrica Outcomes of bile duct drainage by means of ERCP in geriatric patients

    Directory of Open Access Journals (Sweden)

    J. García-Cano

    2007-08-01

    Full Text Available Antecedentes y objetivo: la colangiopancreatografía retrógrada endoscópica (CPRE es habitualmente la técnica de elección para desobstruir la vía biliar. Una gran parte de los pacientes a los que se realiza esta intervención están en edad geriátrica (mayores de 75 años. Nuestro objetivo ha sido valorar la eficacia de la CPRE en este grupo de pacientes, comparado con los de menor edad. Pacientes y métodos: estudio retrospectivo en el que se han incluido los pacientes a quienes se realizó terapéutica biliar endoscópica mediante CPRE en un periodo de cuatro años (2002-2005. Resultados: se realizó CPRE a 178 pacientes en edad geriátrica y a 159 de menor edad. No hubo diferencias en el éxito del drenaje biliar (97,7-98,7%, en el número de complicaciones (11,8-14,4%, ni en la mortalidad (1,1-0,6%. Por el contrario, en el grupo geriátrico hubo más coledocolitiasis (57,3-39,6%, p = 0,004 y se utilizaron más prótesis metálicas autoexpandibles para drenar la ictericia obstructiva tumoral (47-8%, p = 0,0035. En el grupo de menor edad se repitieron más CPRE a los mismos pacientes (4-10%, p = 0,001. Conclusiones: el éxito y la morbimortalidad para drenar la vía biliar mediante CPRE son similares en los pacientes con edad geriátrica y en los de edad inferior. La coledocolitiasis es más frecuente en los pacientes mayores. No se debe excluir a ningún paciente que precise de una CPRE sólo por la edad.Background and objective: endoscopic retrograde cholangiopancreatography (ERCP is usually the procedure of choice for relieving bile duct obstruction. A large number of patients undergoing this intervention are geriatric population (aged 75 years of age and older. Our aim was to assess the efficacy of ERCP in this group of patients as compared to younger ones. Patients and methods: a retrospective study. All patients in whom a therapeutic biliary endoscopy had been performed over a four-year period of time (2002-2005 were included

  14. Niveis sericos das vitaminas lipossoluveis (A, D e E) em pacientes com atresia biliar e hepatite auto-imune e a relação com o estado nutricional e indicadores clinicos e laboratoriais

    OpenAIRE

    Margareth Lopes Galvão Saron

    2008-01-01

    Resumo: As doenças hepáticas crônicas podem induzir à má-absorção de lipídios e vitaminas lipossolúveis e levar ao comprometimento do estado nutricional. O objetivo da pesquisa foi determinar os níveis séricos de vitaminas lipossolúveis (A, D e E) em crianças e adolescentes com atresia biliar (AB) e hepatite auto-imune (HAI) e verificar a relação com o estado nutricional e indicadores laboratoriais e clínicos. O estudo foi transversal e controlado e foram avaliados os pacientes com HAI (n=25...

  15. Recuperação em órgãos e tecidos de Escherichia coli ATCC 25922, inoculada no íleo terminal de ratos com obstrução biliar prolongada

    OpenAIRE

    Rocha, Sergio Luiz, 1958-

    2013-01-01

    Resumo: O objetivo do presente estudo foi investigar a atividade do sistema retículoendotelial em ratos com obstrução biliar de 21 dias , através da recuperação em órgãos e tecidos de bactérias viáveis, previamente injetadas na luz do íleo terminal. Foram utilizados 45 ratos Wistar, machos, com peso médio de 287g, colocados em 3 grupos. Os ratos foram anestesiados por via inalatória com éter etílico em todos os procedimentos cirúrgicos. O grupo I constituiu-se de 14 ratos hígidos, que através...

  16. relationship between principals' management approaches

    African Journals Online (AJOL)

    Admin

    Data were collected using a self-administered questionnaire from a sample of. 211 teachers, 28 principals and 22 chairpersons of parent- teachers association. Data were ..... their role expectation in discipline management. Data from the 20 ...

  17. Principals, agents and research programmes

    OpenAIRE

    Elizabeth Shove

    2003-01-01

    Research programmes appear to represent one of the more powerful instruments through which research funders (principals) steer and shape what researchers (agents) do. The fact that agents navigate between different sources and styles of programme funding and that they use programmes to their own ends is readily accommodated within principal-agent theory with the help of concepts such as shirking and defection. Taking a different route, I use three examples of research programming (by the UK, ...

  18. The distribution of weaver ant pheromones on host trees

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2007-01-01

    The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested for ...... to leaves. Also there was a positive correlation between spot density and the likelihood of being detected by ants. Anal spots may thus function as reliable cues to interacting species and be an important factor in shaping the community around Oecophylla colonies.......The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested...... for correlations between spot density, ant activity and the likelihood of being detected by an ant. Spots were only found on trees with ants. On ant-trees, spots were distributed throughout the trees but with higher densities in areas with high ant activity and pheromone densities were higher on twigs compared...

  19. Hepatobiliary alterations in massive biliary ascariasis: histopathological aspects of an autopsy case Lesões hepatobiliares em ascaridíase biliar maciça: aspectos histopatológicos em um caso de autópsia

    Directory of Open Access Journals (Sweden)

    Luiz Carlos da Costa Gayotto

    1990-04-01

    Full Text Available Hepatobiliary alterations found in an autopsy case of massive Biliary Ascariasis, are reported on histological grounds. Severe cholangitis was the main finding, but other changes were also detected, such as pyloric and intestinal metaplasia, hyperplasia of the epithelial lining, with intraductal papillomas and adenomatous proliferation. Remnants of the worm were observed tightly adhered to the epithelium, forming microscopic intrahepatic calculi. Mucopolysaccharides, especially acid, showed to be strongly positive on the luminal border, and in proliferated glands around the ducts. The authors discuss the similarity between such findings and Oriental Cholangiohepatitis, and suggest that inflammation and the presence of the parasitic remnants are responsible for the hyperplastic and metaplastic changes, similarly with what occurs in chlonorchiasis, fascioliasis and schistosomiasis.Os autores apresentam os aspectos histopatológicos encontrados no fígado de um caso de autópsia de Ascaridíase Biliar maciça. A intensa colangite foi o aspecto predominante, mas outras lesões também foram encontradas, tais como metaplasia pilórica e intestinal, hiperplasia epitelial com papilomas intraductais, e por vezes padrão adenomatoso. Restos do helminto foram encontrados fortemente aderidos ao epitélio, sendo intensa a positividade de mucopolissacárides, principalmente ácidos, na borda luminal do epitélio ductal e em glândulas proliferadas ao redor dos ductos. Os autores discutem a semelhança da Ascaridíase Biliar com a Colangio Hepatite Oriental, e sugerem que o processo inflamatório e a presença de restos do verme são responsáveis pelas alterações hiperplásicas e metaplásicas, analogamente ao que ocorre na clonorquíase, fasciolíase e esquistossomose.

  20. Fuzzy Rules for Ant Based Clustering Algorithm

    Directory of Open Access Journals (Sweden)

    Amira Hamdi

    2016-01-01

    Full Text Available This paper provides a new intelligent technique for semisupervised data clustering problem that combines the Ant System (AS algorithm with the fuzzy c-means (FCM clustering algorithm. Our proposed approach, called F-ASClass algorithm, is a distributed algorithm inspired by foraging behavior observed in ant colonyT. The ability of ants to find the shortest path forms the basis of our proposed approach. In the first step, several colonies of cooperating entities, called artificial ants, are used to find shortest paths in a complete graph that we called graph-data. The number of colonies used in F-ASClass is equal to the number of clusters in dataset. Hence, the partition matrix of dataset founded by artificial ants is given in the second step, to the fuzzy c-means technique in order to assign unclassified objects generated in the first step. The proposed approach is tested on artificial and real datasets, and its performance is compared with those of K-means, K-medoid, and FCM algorithms. Experimental section shows that F-ASClass performs better according to the error rate classification, accuracy, and separation index.

  1. Ant and Mite Diversity Drives Toxin Variation in the Little Devil Poison Frog.

    Science.gov (United States)

    McGugan, Jenna R; Byrd, Gary D; Roland, Alexandre B; Caty, Stephanie N; Kabir, Nisha; Tapia, Elicio E; Trauger, Sunia A; Coloma, Luis A; O'Connell, Lauren A

    2016-06-01

    Poison frogs sequester chemical defenses from arthropod prey, although the details of how arthropod diversity contributes to variation in poison frog toxins remains unclear. We characterized skin alkaloid profiles in the Little Devil poison frog, Oophaga sylvatica (Dendrobatidae), across three populations in northwestern Ecuador. Using gas chromatography/mass spectrometry, we identified histrionicotoxins, 3,5- and 5,8-disubstituted indolizidines, decahydroquinolines, and lehmizidines as the primary alkaloid toxins in these O. sylvatica populations. Frog skin alkaloid composition varied along a geographical gradient following population distribution in a principal component analysis. We also characterized diversity in arthropods isolated from frog stomach contents and confirmed that O. sylvatica specialize on ants and mites. To test the hypothesis that poison frog toxin variability reflects species and chemical diversity in arthropod prey, we (1) used sequencing of cytochrome oxidase 1 to identify individual prey specimens, and (2) used liquid chromatography/mass spectrometry to chemically profile consumed ants and mites. We identified 45 ants and 9 mites in frog stomachs, including several undescribed species. We also showed that chemical profiles of consumed ants and mites cluster by frog population, suggesting different frog populations have access to chemically distinct prey. Finally, by comparing chemical profiles of frog skin and isolated prey items, we traced the arthropod source of four poison frog alkaloids, including 3,5- and 5,8-disubstituted indolizidines and a lehmizidine alkaloid. Together, the data show that toxin variability in O. sylvatica reflects chemical diversity in arthropod prey.

  2. EVOLUÇÃO DA FIBROSE BILIAR SECUNDÁRIA EM RATOS TRATADOS MEDIANTE DERIVAÇÃO BÍLIO-DUODENAL OU BÍLIO-JEJUNAL COM AL��A DE ROUX MEDINDO 5, 10 E 15 CM

    Directory of Open Access Journals (Sweden)

    Pandolfi Jr. H.

    2001-01-01

    Full Text Available A modalidade de derivação bílio-digestiva empregada no tratamento da colestase extra-hepática crônica pode influenciar na reparação das lesões hepáticas. Avaliou-se o desempenho das derivações bílio-duodenal e bílio-jejunal em Y de Roux com alça exclusa de diferentes comprimentos na reparação das lesões morfológicas e funcionais do fígado de ratos com fibrose biliar secundária. Foram utilizados ratos Wistar, com 15 dias de obstrução biliar, alocados em 5 grupos de 6 animais. O grupo OB caracterizou as alterações da fibrose biliar. Os animais remanescentes foram tratados mediante derivação com o duodeno (grupo DBD, e com o jejuno, em alça exclusa de 5cm (grupo DBJ5, 10cm (grupo DBJ10 e 15cm (grupo DBJ15, sendo reavaliados 3 meses depois. Outros 6 animais foram submetidos à intervenção simulada e considerados grupo controle (IS. Todos animais foram submetidos à avaliação morfométrica do fígado, análise bioquímica do sangue e microbiológica da bile, estudo da função mitocondrial hepática e verificação do peso úmido do fígado e do baço. Na análise estatística adotou-se o nível de significância de 5%. Houve aumento significativo do peso estimado, em g/Kg de peso corporal, dos ductos biliares, da fibrose e dos hepatócitos nos animais do grupo OB (medianas de 1,30; 10,03 e 37,0 em relação aos animais controles (IS (medianas de 0,03; zero e 29,37. Após tratamento, ocorreu regressão significativa do peso estimado dos ductos biliares e da fibrose, com valores medianos de 0,22 e 0,22 para o grupo DBD, 0,45 e 3,31 para o grupo DBJ5 e 0,22 e 5,0 para o grupo DBJ15. Houve regressão significativa do peso estimado dos hepatócitos apenas nos grupos derivados com o jejuno, com valores medianos de 31,93; 24,46 e 28,52. Ocorreu aumento significativo do peso úmido do fígado e do baço no grupo OB (medianas em g/Kg de peso corporal de 49,85 e 5,71 em relação ao grupo IS (30,0 e 3,04. Houve regress

  3. Kin-informative recognition cues in ants

    DEFF Research Database (Denmark)

    Nehring, Volker; Evison, Sophie E F; Santorelli, Lorenzo A

    2011-01-01

    behaviour is thought to be rare in one of the classic examples of cooperation--social insect colonies--because the colony-level costs of individual selfishness select against cues that would allow workers to recognize their closest relatives. In accord with this, previous studies of wasps and ants have...... found little or no kin information in recognition cues. Here, we test the hypothesis that social insects do not have kin-informative recognition cues by investigating the recognition cues and relatedness of workers from four colonies of the ant Acromyrmex octospinosus. Contrary to the theoretical...... prediction, we show that the cuticular hydrocarbons of ant workers in all four colonies are informative enough to allow full-sisters to be distinguished from half-sisters with a high accuracy. These results contradict the hypothesis of non-heritable recognition cues and suggest that there is more potential...

  4. Ant parasite queens revert to mating singly

    DEFF Research Database (Denmark)

    Sumner, Seirian; Hughes, William Owen Hamar; Pedersen, Jes Søe

    2004-01-01

    quantified and they tend to be similar in related species. Here we compare the mating strategies of the leaf-cutting ant Acromyrmex echinatior and its recently derived social parasite Acromyrmex insinuator, which is also its closest relative 2 (see Fig. 1 ). We find that although the host queens mate with up......A parasitic ant has abandoned the multiple mating habit of the queens of its related host. Multiple mating (polyandry) is widespread among animal groups, particularly insects 1 . But the factors that maintain it and underlie its evolution are hard to verify because benefits and costs are not easily...... to a dozen different males, the social parasite mates only singly. This rapid and surprising reversion to single mating in a socially parasitic ant indicates that the costs of polyandry are probably specific to a free-living lifestyle....

  5. The worldwide expansion of the Argentine ant

    DEFF Research Database (Denmark)

    Vogel, Valerie; Pedersen, Jes Søe; Giraud, Tatiana

    2010-01-01

    Aim The aim of this study was to determine the number of successful establishments of the invasive Argentine ant outside native range and to see whether introduced supercolonies have resulted from single or multiple introductions. We also compared the genetic diversity of native versus introduced...... supercolonies to assess the size of the propagules (i.e. the number of founding individuals) at the origin of the introduced supercolonies. Location Global. Methods We used mitochondrial DNA (mtDNA) markers and microsatellite loci to study 39 supercolonies of the Argentine ant Linepithema humile covering both......) and secondary introductions (from sites with established invasive supercolonies) were important in the global expansion of the Argentine ant. In combination with the similar social organization of colonies in the native and introduced range, this indicates that invasiveness did not evolve recently as a unique...

  6. Desert ants learn vibration and magnetic landmarks.

    Directory of Open Access Journals (Sweden)

    Cornelia Buehlmann

    Full Text Available The desert ants Cataglyphis navigate not only by path integration but also by using visual and olfactory landmarks to pinpoint the nest entrance. Here we show that Cataglyphis noda can additionally use magnetic and vibrational landmarks as nest-defining cues. The magnetic field may typically provide directional rather than positional information, and vibrational signals so far have been shown to be involved in social behavior. Thus it remains questionable if magnetic and vibration landmarks are usually provided by the ants' habitat as nest-defining cues. However, our results point to the flexibility of the ants' navigational system, which even makes use of cues that are probably most often sensed in a different context.

  7. Ant-plants and fungi: a new threeway symbiosis.

    Science.gov (United States)

    Defossez, Emmanuel; Selosse, Marc-André; Dubois, Marie-Pierre; Mondolot, Laurence; Faccio, Antonella; Djieto-Lordon, Champlain; McKey, Doyle; Blatrix, Rumsaïs

    2009-06-01

    Symbioses between plants and fungi, fungi and ants, and ants and plants all play important roles in ecosystems. Symbioses involving all three partners appear to be rare. Here, we describe a novel tripartite symbiosis in which ants and a fungus inhabit domatia of an ant-plant, and present evidence that such interactions are widespread. We investigated 139 individuals of the African ant-plant Leonardoxa africana for occurrence of fungus. Behaviour of mutualist ants toward the fungus within domatia was observed using a video camera fitted with an endoscope. Fungi were identified by sequencing a fragment of their ribosomal DNA. Fungi were always present in domatia occupied by mutualist ants but never in domatia occupied by opportunistic or parasitic ants. Ants appear to favour the propagation, removal and maintenance of the fungus. Similar fungi were associated with other ant-plants in Cameroon. All belong to the ascomycete order Chaetothyriales; those from L. africana formed a monophyletic clade. These new plant-ant-fungus associations seem to be specific, as demonstrated within Leonardoxa and as suggested by fungal phyletic identities. Such tripartite associations are widespread in African ant-plants but have long been overlooked. Taking fungal partners into account will greatly enhance our understanding of symbiotic ant-plant mutualisms.

  8. Ants of the Peloponnese, Greece (Hymenoptera: Formicidae

    Directory of Open Access Journals (Sweden)

    Borowiec Lech

    2017-09-01

    Full Text Available This paper relates to material obtained during two field trips to the Peloponnese in 2013 and 2016. With the inclusion of some hitherto unpublished ant material, it gives new records from a total of 92 sampling localities. 129 species (including morphospecies not attributed to any known taxon of ants have been recorded from the Peloponnese (southern Greece, 27 of which have been recorded from this region for the first time. Lasius reginae and 5 other morphospecies attributed only to species complexes are new to Greece.

  9. Image Edge Tracking via Ant Colony Optimization

    Science.gov (United States)

    Li, Ruowei; Wu, Hongkun; Liu, Shilong; Rahman, M. A.; Liu, Sanchi; Kwok, Ngai Ming

    2018-04-01

    A good edge plot should use continuous thin lines to describe the complete contour of the captured object. However, the detection of weak edges is a challenging task because of the associated low pixel intensities. Ant Colony Optimization (ACO) has been employed by many researchers to address this problem. The algorithm is a meta-heuristic method developed by mimicking the natural behaviour of ants. It uses iterative searches to find the optimal solution that cannot be found via traditional optimization approaches. In this work, ACO is employed to track and repair broken edges obtained via conventional Sobel edge detector to produced a result with more connected edges.

  10. Principal Curves on Riemannian Manifolds.

    Science.gov (United States)

    Hauberg, Soren

    2016-09-01

    Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimizes a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend to imply that the methods only work well when the manifold is mostly flat within the support of the generating distribution. We argue that instead of generalizing linear Euclidean models, it is more fruitful to generalize non-linear Euclidean models. Specifically, we extend the classic Principal Curves from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls of traditional geodesic approaches. We empirically demonstrate the effectiveness of the Riemannian principal curves on several manifolds and datasets.

  11. The Principal and the Law. Elementary Principal Series No. 7.

    Science.gov (United States)

    Doverspike, David E.; Cone, W. Henry

    Developments over the past 25 years in school-related legal issues in elementary schools have significantly changed the principal's role. In 1975, a decision of the U.S. Supreme Court established three due-process guidelines for short-term suspension. The decision requires student notification of charges, explanation of evidence, and an informal…

  12. Intersexual Trophic Niche Partitioning in an Ant-Eating spider (Araneae: Zodariidae)

    DEFF Research Database (Denmark)

    Pekár, Stanislav; Martisová, Martina; Bilde, T.

    2011-01-01

    lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants...... that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning. Methodology/Principal Findings Comparative analysis of trophic morphology (the chelicerae) and body size of males, females and juveniles...... demonstrated highly female biased SSD (Sexual Size Dimorphism) in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size...

  13. Oecophylla smaragdina food conversion efficiency: prospects for ant farming

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim

    2011-01-01

    can be combined with the use of the ants in biological control programmes in tropical plantations where pest insects are converted into ant biomass. To assess the cost-benefits of ant farming based on artificial feeding, food consumption and food conversion efficiency (ECI) of Oecophylla smaragdina......Oecophylla ants are sold at high prices on several commercial markets as a human delicacy, as pet food or as traditional medicine. Currently markets are supplied by ants collected from the wild; however, an increasing interest in ant farming exists as all harvest is easily sold and as ant farming...... selling prices these efficiencies led to rates of return from 1.52 to 4.56, respectively, if: (i) protein is supplied from commercial products; or (ii) alternatively supplied from free sources such as insects and kitchen waste. These results suggest that Oecophylla ant farming may become highly profitable...

  14. Hybrid Bee Ant Colony Algorithm for Effective Load Balancing And ...

    African Journals Online (AJOL)

    PROF. OLIVER OSUAGWA

    Ant Colony algorithm is used in this hybrid Bee Ant Colony algorithm to solve load balancing issues ... Genetic Algorithm (MO-GA) for dynamic job scheduling that .... Information Networking and Applications Workshops. [7]. M. Dorigo & T.

  15. The use of weaver ants (Oecophylla spp.) in tropical agriculture

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim

    2011-01-01

    by the consumed pest insects, can be harvested and utilised for nutrition as they are tasty and high in proteins, vitamins and minerals. Thus, plantations may function as ant farms and in addition to plant production also hosts the production of edible animal protein. In this setup harmful pest insects are turned...... farming as a way forward to solve an increasing future demand for protein. Weaver ant farming may build on natural food collected by the ants or alternatively be boosted by feeding the ant colonies actively with protein and sugar. In both cases, when ant biocontrol is combined with ant farming......, the environmental cost of protein production may fall even lower than for other insects as the ants feed on pests that would otherwise reduce the plant yield and since the farming area is simultaneously in use for plant production. In this presentation I provide data showing (i) how the harvest of ants can...

  16. Surface analysis the principal techniques

    CERN Document Server

    Vickerman, John C

    2009-01-01

    This completely updated and revised second edition of Surface Analysis: The Principal Techniques, deals with the characterisation and understanding of the outer layers of substrates, how they react, look and function which are all of interest to surface scientists. Within this comprehensive text, experts in each analysis area introduce the theory and practice of the principal techniques that have shown themselves to be effective in both basic research and in applied surface analysis. Examples of analysis are provided to facilitate the understanding of this topic and to show readers how they c

  17. Principal bundles the classical case

    CERN Document Server

    Sontz, Stephen Bruce

    2015-01-01

    This introductory graduate level text provides a relatively quick path to a special topic in classical differential geometry: principal bundles.  While the topic of principal bundles in differential geometry has become classic, even standard, material in the modern graduate mathematics curriculum, the unique approach taken in this text presents the material in a way that is intuitive for both students of mathematics and of physics. The goal of this book is to present important, modern geometric ideas in a form readily accessible to students and researchers in both the physics and mathematics communities, providing each with an understanding and appreciation of the language and ideas of the other.

  18. Dealing with water deficit in Atta ant colonies: large ants scout for water while small ants transport it

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Da-Silva

    2012-07-01

    Leafcutter ants (Atta sexdens rubropilosa (Forel 1908 have an elaborate social organization, complete with caste divisions. Activities carried out by specialist groups contribute to the overall success and survival of the colony when it is confronted with environmental challenges such as dehydration. Ants detect variations in humidity inside the nest and react by activating several types of behavior that enhance water uptake and decrease water loss, but it is not clear whether or not a single caste collects water regardless of the cost of bringing this resource back to the colony. Accordingly, we investigated water collection activities in three colonies of Atta sexdens rubropilosa experimentally exposed to water stress. Specifically, we analyzed whether or not the same ant caste foraged for water, regardless of the absolute energetic cost (distance of transporting this resource back to the colony. Our experimental design offered water sources at 0 m, 1 m and 10 m from the nest. We studied the body size of ants near the water sources from the initial offer of water (time  =  0 to 120 min, and tested for specialization. We observed a reduction in the average size and variance of ants that corroborated the specialization hypothesis. Although the temporal course of specialization changed with distance, the final outcome was similar among distances. Thus, we conclude that, for this species, a specialist (our use of the word “specialist” does not mean exclusive task force is responsible for collecting water, regardless of the cost of transporting water back to the colony.

  19. Extended phenotype: nematodes turn ants into bird-dispersed fruits

    DEFF Research Database (Denmark)

    Hughes, D P; Kronauer, D J C; Boomsma, J J

    2008-01-01

    A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs.......A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs....

  20. Histrionicotoxin alkaloids finally detected in an ant

    DEFF Research Database (Denmark)

    Jones, Tappey H.; Adams, Rachelle Martha Marie; Spande, Thomas F.

    2012-01-01

    Workers of the ant Carebarella bicolor collected in Panama were found to have two major poison-frog alkaloids, cis- and trans-fused decahydroquinolines (DHQs) of the 269AB type, four minor 269AB isomers, two minor 269B isomers, and three isomers of DHQ 271D. For the first time in an ant, however......) sp., were found to have a very similar DHQ complex but failed to show HTXs. Several new DHQ alkaloids of MW 271 (named in the frog as 271G) are reported from the above ants that have both m/z 202 and 204 as major fragment ions, unlike the spectrum seen for the poison-frog alkaloid 271D, which has...... only an m/z 204 base peak. Found also for the first time in skin extracts from the comparison frog Oophaga granulifera of Costa Rica is a trace DHQ of MW 273. It is coded as 273F in the frog; a different isomer is found in the ant....

  1. Ants, rodents and seed predation in Proteaceae

    African Journals Online (AJOL)

    ... their nests extremely rapidly. One benefit of the ant-plant interaction may be seed escape ... (odourless to humans when dry) household glue or, b) placing seed in a Petri dish ... the layout of exclosures was completed. Response was not as.

  2. The evolution of invasiveness in garden ants

    DEFF Research Database (Denmark)

    Cremer, Sylvia; Ugelvig, Line Vej; Drijfhout, Falko P

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its ra...

  3. The ejaculatory biology of leafcutter ants

    DEFF Research Database (Denmark)

    den Boer, Susanne; Stürup, Marlene; Boomsma, Jacobus Jan

    2015-01-01

    understanding of the fundamental biology of ejaculate production, transfer and physiological function remains extremely limited. We studied the ejaculation process in the leafcutter ant Atta colombica and found that it starts with the appearance of a clear pre-ejaculatory fluid (PEF) at the tip...

  4. Mating, hybridisation and introgression in Lasius ants

    NARCIS (Netherlands)

    Have, van der T.M.; Pedersen, J.S.; Boomsma, J.J.

    2011-01-01

    Recent reviews have shown that hybridisation among ant species is likely to be more common than previously appreciated. but that documented cases of introgression remain rare. After molecular phylogenetic work had shown that European Lasius niger (LINNAEUS, 1758) and L. psammophilus SEIFERT, 1992

  5. Ants recognize foes and not friends

    Science.gov (United States)

    Guerrieri, Fernando J.; Nehring, Volker; Jørgensen, Charlotte G.; Nielsen, John; Galizia, C. Giovanni; d'Ettorre, Patrizia

    2009-01-01

    Discriminating among individuals and rejecting non-group members is essential for the evolution and stability of animal societies. Ants are good models for studying recognition mechanisms, because they are typically very efficient in discriminating ‘friends’ (nest-mates) from ‘foes’ (non-nest-mates). Recognition in ants involves multicomponent cues encoded in cuticular hydrocarbon profiles. Here, we tested whether workers of the carpenter ant Camponotus herculeanus use the presence and/or absence of cuticular hydrocarbons to discriminate between nest-mates and non-nest-mates. We supplemented the cuticular profile with synthetic hydrocarbons mixed to liquid food and then assessed behavioural responses using two different bioassays. Our results show that (i) the presence, but not the absence, of an additional hydrocarbon elicited aggression and that (ii) among the three classes of hydrocarbons tested (unbranched, mono-methylated and dimethylated alkanes; for mono-methylated alkanes, we present a new synthetic pathway), only the dimethylated alkane was effective in eliciting aggression. Our results suggest that carpenter ants use a fundamentally different mechanism for nest-mate recognition than previously thought. They do not specifically recognize nest-mates, but rather recognize and reject non-nest-mates bearing odour cues that are novel to their own colony cuticular hydrocarbon profile. This begs for a reappraisal of the mechanisms underlying recognition systems in social insects. PMID:19364750

  6. Recognition of social identity in ants

    DEFF Research Database (Denmark)

    Bos, Nick; d'Ettorre, Patrizia

    2012-01-01

    Recognizing the identity of others, from the individual to the group level, is a hallmark of society. Ants, and other social insects, have evolved advanced societies characterized by efficient social recognition systems. Colony identity is mediated by colony specific signature mixtures, a blend...

  7. Plasmodium parasitaemia among pregnant women attending ante ...

    African Journals Online (AJOL)

    ... Ante-Natal Clinic at Military Hospital Port Harcourt, Rivers State, Nigeria using the Standard parasitological technique. Venous blood was collected from 200 pregnant women, both thick and thin blood films were made on clean greese-free glass slide and stained with 10% Giemsa stains diluted with 7.2 buffered water for ...

  8. Operant conditioning in the ant Myrmica sabuleti.

    Science.gov (United States)

    Cammaerts, M C

    2004-11-30

    Operant conditioning could be obtained in the ant Myrmica sabuleti by presenting to the workers, during a six-day period, an apparatus containing either sugared water or meat as a reward. The conditioning obtained using sugared water as a reward was short lasting. A reconditioning was more persistent and lasted four hours. The ants' response was very precise, since they exhibited it only in front of an apparatus identical to that used during the training phase. Operant conditioning obtained using meat as a reward was more pronounced than that obtained by using sugared water, probably because meat is more valuable as a reward than sugar for the species studied, which is essentially a carnivorous one. Such a conditioning was rather persistent. Indeed, a first operant conditioning obtained by using meat as a reward could still be detected after seven hours, and a reconditioning was still significant after eight hours. One day after this eight-hour period without rewarding the ants, the response was higher again and a further day later, it was still significant. Since the operant conditioning is easy to perform and quantify and since the ants' response is very precise, such a conditioning can be used for further studying M. sabuleti workers' visual perception.

  9. A global database of ant species abundances

    Science.gov (United States)

    Gibb, Heloise; Dunn, Rob R.; Sanders, Nathan J.; Grossman, Blair F.; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N.; Angulo, Elena; Armbrecht, Ingre; Arnan, Xavier; Baccaro, Fabricio B.; Bishop, Tom R.; Boulay, Raphael; Bruhl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A.; Ellison, Aaron M.; Enriquez, Martha L.; Fayle, Tom M.; Feener Jr., Donald H.; Fisher, Brian L.; Fisher, Robert N.; Fitpatrick, Matthew C.; Gomez, Cristanto; Gotelli, Nicholas J.; Gove, Aaron; Grasso, Donato A.; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H.; Majer, Jonathan; McGlynn, Terrence P.; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M.; Resasco, Julian; Retana, Javier; Silva, Rogerio R.; Sorger, Magdalena D.; Souza, Jorge; Suarez, Andrew V.; Tista, Melanie; Vasconcelos, Heraldo L.; Vonshak, Merav; Weiser, Michael D.; Yates, Michelle; Parr, Catherine L.

    2017-01-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardised methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing dataset.

  10. Studies on the environmental implications of ants (Hymenoptera ...

    African Journals Online (AJOL)

    A study of ants associated wh two synanthropcenvironments in Awka was carried out in 2008 using pitfall and bait traps. The study yelded a total of 561 ants wth 409 obtaned from the hemisynanthrophic environment while 192 ants were collected from the endophilic environment. The percentage occurrence, total dstribution ...

  11. Dynamics of an ant-plant-pollinator model

    Science.gov (United States)

    Wang, Yuanshi; DeAngelis, Donald L.; Nathaniel Holland, J.

    2015-03-01

    In this paper, we consider plant-pollinator-ant systems in which plant-pollinator interaction and plant-ant interaction are both mutualistic, but there also exists interference of pollinators by ants. The plant-pollinator interaction can be described by a Beddington-DeAngelis formula, so we extend the formula to characterize plant-pollinator mutualisms, including the interference by ants, and form a plant-pollinator-ant model. Using dynamical systems theory, we show uniform persistence of the model. Moreover, we demonstrate conditions under which boundary equilibria are globally asymptotically stable. The dynamics exhibit mechanisms by which the three species could coexist when ants interfere with pollinators. We define a threshold in ant interference. When ant interference is strong, it can drive plant-pollinator mutualisms to extinction. Furthermore, if the ants depend on pollination mutualism for their persistence, then sufficiently strong ant interference could lead to their own extinction as well. Yet, when ant interference is weak, plant-ant and plant-pollinator mutualisms can promote the persistence of one another.

  12. Ants Orasest ja Anne Lange monograafiast / Jüri Talvet

    Index Scriptorium Estoniae

    Talvet, Jüri, 1945-

    2005-01-01

    Arvustus: Oras, Ants. Luulekool. I, Apoloogia / koostajad Hando Runnel ja Jaak Rähesoo. Tartu : Ilmamaa, 2003 ; Oras, Ants. Luulekool II, Meistriklass. Tartu : Ilmamaa, 2004 ; Lange, Anne. Ants Oras : [kirjandusteadlane, -kriitik ja tõlkija (1900-1982)]. Tartu : Ilmamaa, 2004

  13. Are ant feces nutrients for plants? A metabolomics approach to elucidate the nutritional effects on plants hosting weaver ants

    DEFF Research Database (Denmark)

    Vidkjær, Nanna Hjort; Wollenweber, Bernd; Gislum, René

    2015-01-01

    Weaver ants (genus Oecophylla) are tropical carnivorous ant species living in high numbers in the canopies of trees. The ants excrete copious amounts of fecal matter on leaf surfaces, and these feces may provide nutrients to host trees. This hypothesis is supported by studies of ant......-plant interactions involving other ant species that have demonstrated the transfer of nutrients from ants to plants. In this 7-months study, a GC–MS-based metabolomics approach along with an analysis of total nitrogen and carbon levels was used to study metabolic changes in ant-hosting Coffea arabica plants compared...... with control plants. The results showed elevated levels of total nitrogen, amino acids, fatty acids, caffeine, and secondary metabolites of the phenylpropanoid pathway in leaves from ant-hosting plants. Minor effects were observed for sugars, whereas little or no effect was observed for organic acids, despite...

  14. Plant lock and ant key: pairwise coevolution of an exclusion filter in an ant-plant mutualism.

    Science.gov (United States)

    Brouat, C; Garcia, N; Andary, C; McKey, D

    2001-10-22

    Although observations suggest pairwise coevolution in specific ant-plant symbioses, coevolutionary processes have rarely been demonstrated. We report on, what is to the authors' knowledge, the strongest evidence yet for reciprocal adaptation of morphological characters in a species-specific ant-plant mutualism. The plant character is the prostoma, which is a small unlignified organ at the apex of the domatia in which symbiotic ants excavate an entrance hole. Each myrmecophyte in the genus Leonardoxa has evolved a prostoma with a different shape. By performing precise measurements on the prostomata of three related myrmecophytes, on their specific associated ants and on the entrance holes excavated by symbiotic ants at the prostomata, we showed that correspondence of the plant and ant traits forms a morphological and behavioural filter. We have strong evidence for coevolution between the dimensions and shape of the symbiotic ants and the prostoma in one of the three ant-Leonardoxa associations.

  15. School Uniforms: Guidelines for Principals.

    Science.gov (United States)

    Essex, Nathan L.

    2001-01-01

    Principals desiring to develop a school-uniform policy should involve parents, teachers, community leaders, and student representatives; beware restrictions on religious and political expression; provide flexibility and assistance for low-income families; implement a pilot program; align the policy with school-safety issues; and consider legal…

  16. The Principal and Tort Liability.

    Science.gov (United States)

    Stern, Ralph D.

    The emphasis of this chapter is on the tort liability of principals, especially their commission of unintentional torts or torts resulting from negligent conduct. A tort is defined as a wrongful act, not including a breach of contract or trust, which results in injury to another's person, property, or reputation and for which the injured party is…

  17. Teachers' Perspectives on Principal Mistreatment

    Science.gov (United States)

    Blase, Joseph; Blase, Jo

    2006-01-01

    Although there is some important scholarly work on the problem of workplace mistreatment/abuse, theoretical or empirical work on abusive school principals is nonexistent. Symbolic interactionism was the theoretical structure for the present study. This perspective on social research is founded on three primary assumptions: (1) individuals act…

  18. Principal minors and rhombus tilings

    International Nuclear Information System (INIS)

    Kenyon, Richard; Pemantle, Robin

    2014-01-01

    The algebraic relations between the principal minors of a generic n × n matrix are somewhat mysterious, see e.g. Lin and Sturmfels (2009 J. Algebra 322 4121–31). We show, however, that by adding in certain almost principal minors, the ideal of relations is generated by translations of a single relation, the so-called hexahedron relation, which is a composition of six cluster mutations. We give in particular a Laurent-polynomial parameterization of the space of n × n matrices, whose parameters consist of certain principal and almost principal minors. The parameters naturally live on vertices and faces of the tiles in a rhombus tiling of a convex 2n-gon. A matrix is associated to an equivalence class of tilings, all related to each other by Yang–Baxter-like transformations. By specializing the initial data we can similarly parameterize the space of Hermitian symmetric matrices over R,C or H the quaternions. Moreover by further specialization we can parametrize the space of positive definite matrices over these rings. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Cluster algebras mathematical physics’. (paper)

  19. Ligadura de ducto biliar como modelo de estudo da síndrome hepatopulmonar e estresse oxidativo Common bile duct ligation as a model of hepatopulmonary syndrome and oxidative stress

    Directory of Open Access Journals (Sweden)

    Juliana Tieppo

    2005-12-01

    Full Text Available RACIONAL: A síndrome hepatopulmonar é caracterizada por uma disfunção hepática e pela existência de dilatações dos vasos pulmonares, levando a alterações nas trocas gasosas, tendo algumas das suas características observadas de forma experimental no modelo de ligadura de ducto biliar. OBJETIVOS: Avaliar o estresse oxidativo no tecido pulmonar de ratos cirróticos por ligadura de ducto biliar comum. MATERIAIS E MÉTODOS: Foram utilizados 12 ratos machos Wistar, pesando entre 200 e 300 g, divididos em dois grupos: controles (Co = 6 e cirróticos (Ci = 6. Foram realizadas avaliações de transaminases, gasometria arterial, avaliação da lipoperoxidação (substâncias reativas ao ácido tiobarbitúrico e quimiluminescência e quantificação da atividade enzimática antioxidante através das concentrações da enzima superóxido dismutase. Os tecidos analisados para avaliação da síndrome hepatopulmonar foram o fígado cirrótico e o pulmão. RESULTADOS: Os animais com ligadura de ducto biliar apresentaram alteração nas transaminases: aspartato aminotransferase, Co = 105,3 ± 43/Ci = 500,5 ± 90,3 alanina aminotransferase, Co = 78,75 ± 37,7/Ci = 162,75 ± 35,4 e fosfatase alcalina, Co = 160 ± 20,45/Ci = 373,25 ± 45,44. Em relação à lipoperoxidação e à resposta antioxidante, estas também apresentaram diferenças estatisticamente significativas quando avaliadas no pulmão (substâncias reativas ao ácido tiobarbitúrico Co = 0,87 ± 0,3/Ci = 2,01 ± 0,9; quimiluminescência Co = 16008,41 ± 1171,45/Ci = 20250,36 ± 827,82; superóxido dismutase Co = 6,66 ± 1,34/Ci = 16,06 ± 2,67. CONCLUSÕES: Os dados obtidos sugerem que no modelo experimental de cirrose por ligadura de ducto biliar há aumento significativo da lipoperoxidação no tecido pulmonar, bem como aumento na atividade da enzima antioxidante superóxido dismutase, sugerindo a presença de dano pulmonar decorrente da cirrose biliar secundária.BACKGROUND: The

  20. Paucity of intrahepatic bile ducts in infancy: experience of a tertiary center Hipoplasia de vias biliares intra-hepáticas na infância: experiência de um serviço terciário

    Directory of Open Access Journals (Sweden)

    Adriana Maria Alves De Tommaso

    2004-09-01

    Full Text Available BACKGROUND: Intrahepatic cholestasis secondary to paucity of bile duct is an alteration of the anatomic integrity of the biliary tract. Can be defined only histologically and, clinically, two categories are recognized: syndromic and non-syndromic, where the prognosis is generally more severe. AIM: To evaluate the history, clinical and biochemical characteristics, etiology and improvement of children who have paucity of intrahepatic bile duct followed at tertiary center. PATIENTS AND METHODS: Eleven children with paucity of intrahepatic bile duct, followed at the Pediatric Hepatology Service of the University Hospital, Campinas, SP, Brazil, were evaluated in the period from 1986 to 2001. RESULTS: Among the patients, three presented the syndromic and eight the non-syndromic form (two with alpha-1-antitrypsin deficiency, one with lues, one secondary to sepsis, three with probable etiology by cytomegalovirus and one without a definite etiology. Referral ranged from 31 to 1185 days. Birth weights ranged from 1920 g to 3590 g. Most of the patients presented pale stools. The median bile duct/portal tract ratio was 0.14. The majority of the children presented a favorable follow-up, regardless of the form of presentation. CONCLUSION: Paucity of intrahepatic bile ducts should be considered in children with cholestasis and its differentiation from extrahepatic causes of neonatal cholestasis is important in order to avoid surgery. Diagnosis of non-syndromic form should not be regarded as unfavorable prognosis, as the evolution is probably related to the etiology in this form of presentation.RACIONAL: A hipoplasia das vias biliares intra-hepáticas é causa de colestase secundária a uma alteração na integridade anatômica do trato biliar. A definição é dada pelo exame histopatológico e, do ponto de vista clínico, pode ser classificada em sindrômica e não-sindrômica onde o prognóstico é, geralmente, mais grave. OBJETIVO: Avaliar a hist

  1. Interactive effects of soil-dwelling ants, ant mounds and simulated grazing on local plant community composition

    NARCIS (Netherlands)

    Veen, G.F.; Olff, H.

    2011-01-01

    Interactions between aboveground vertebrate herbivores and subterranean yellow meadow ants (Lasius flavus) can drive plant community patterns in grassland ecosystems. Here, we study the relative importance of the presence of ants (L. flavus) and ant mounds under different simulated grazing regimes

  2. Edge detection in digital images using Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Marjan Kuchaki Rafsanjani

    2015-11-01

    Full Text Available Ant Colony Optimization (ACO is an optimization algorithm inspired by the behavior of real ant colonies to approximate the solutions of difficult optimization problems. In this paper, ACO is introduced to tackle the image edge detection problem. The proposed approach is based on the distribution of ants on an image; ants try to find possible edges by using a state transition function. Experimental results show that the proposed method compared to standard edge detectors is less sensitive to Gaussian noise and gives finer details and thinner edges when compared to earlier ant-based approaches.

  3. Tratamiento en pacientes operados de estómago con ácidos biliares elevados y Helicobacter pylori positivo Treatment in patients operated on of the stomach with elevated biliary acids and positive Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Héctor Rubén Hernández Garcés

    2008-04-01

    Full Text Available Se realizó un estudio del tipo experimental, no ciego y aleatorizado, constituido por 30 pacientes adultos de uno y otro sexos con diagnóstico de gastritis crónica alcalina por reflujo duodenogástrico, en resecados de estómago (Billroth I, Billroth II, mediante endoscopia superior, con ácidos biliares totales elevados y Helicobacter pylori positivo. Estos pacientes se distribuyeron en 2 grupos de tratamiento durante 8 semanas. El grupo A, de 15 pacientes, recibió tratamiento con: subcitrato de bismuto coloidal (Q-ulcer, metronidazol y tetraciclina, más ranitidina como antihistamínico H2. El grupo B, de 15 pacientes, se le administró celulosa microcristalina (Microcel. Ambos grupos recibieron metoclopramida como fármaco procinético durante todo el tratamiento. Los índices de erradicación de la infección por H. pylori fueron del 46,7 % para el grupo A y del 42,9 % para el grupo B. La concentración de ácidos biliares totales al final del tratamiento disminuyó en el 53,3% de los pacientes del grupo A y en el 71,4% de los pacientes del grupo B. La concentración de ácidos biliares totales en el remanente gástrico al final del tratamiento, no influyó en la evaluación clínica, endoscópica e histológica de los pacientes en ambos esquemas de tratamiento. No se presentaron efectos adversos secundarios en los pacientes del grupo A y 1 paciente (6,6 % del grupo B abandonó el estudio al empeorar su cuadro clínico, el cual fue intervenido quirúrgicamente, por lo que se considera fracaso del tratamiento. Se concluye que estos esquemas terapéuticos no fueron eficacesA non-blind randomized experimental study was undertaken. It included 30 adults of both sexes with diagnosis of alkaline chronic gastritis due to duodenogastric reflux, in stomach resections (Billroth I, Billroth II, by upper endoscopy, with elevated total biliary acids and positive Helicobacter pylori. These patients were divided into 2 groups of treatment during 8

  4. The Pied Piper: A Parasitic Beetle's Melodies Modulate Ant Behaviours.

    Directory of Open Access Journals (Sweden)

    Andrea Di Giulio

    Full Text Available Ants use various communication channels to regulate their social organisation. The main channel that drives almost all the ants' activities and behaviours is the chemical one, but it is long acknowledged that the acoustic channel also plays an important role. However, very little is known regarding exploitation of the acoustical channel by myrmecophile parasites to infiltrate the ant society. Among social parasites, the ant nest beetles (Paussus are obligate myrmecophiles able to move throughout the colony at will and prey on the ants, surprisingly never eliciting aggression from the colonies. It has been recently postulated that stridulatory organs in Paussus might be evolved as an acoustic mechanism to interact with ants. Here, we survey the role of acoustic signals employed in the Paussus beetle-Pheidole ant system. Ants parasitised by Paussus beetles produce caste-specific stridulations. We found that Paussus can "speak" three different "languages", each similar to sounds produced by different ant castes (workers, soldiers, queen. Playback experiments were used to test how host ants respond to the sounds emitted by Paussus. Our data suggest that, by mimicking the stridulations of the queen, Paussus is able to dupe the workers of its host and to be treated as royalty. This is the first report of acoustic mimicry in a beetle parasite of ants.

  5. The interactions of ants with their biotic environment.

    Science.gov (United States)

    Chomicki, Guillaume; Renner, Susanne S

    2017-03-15

    This s pecial feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this s pecial feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication. © 2017 The Author(s).

  6. Ant species confer different partner benefits on two neotropical myrmecophytes.

    Science.gov (United States)

    Frederickson, Megan E

    2005-04-01

    The dynamics of mutualistic interactions involving more than a single pair of species depend on the relative costs and benefits of interaction among alternative partners. The neotropical myrmecophytes Cordia nodosa and Duroia hirsuta associate with several species of obligately symbiotic ants. I compared the ant partners of Cordia and Duroia with respect to two benefits known to be important in ant-myrmecophyte interactions: protection against herbivores provided by ants, and protection against encroaching vegetation provided by ants. Azteca spp., Myrmelachista schumanni, and Allomerus octoarticulatus demerarae ants all provide the leaves of Cordia and Duroia some protection against herbivores. However, Azteca and Allomerus provide more protection than does Myrmelachista to the leaves of their host plants. Although Allomerus protects the leaves of its hosts, plants occupied by Allomerus suffer more attacks by herbivores to their stems than do plants occupied by other ants. Relative to Azteca or Allomerus, Myrmelachista ants provide better protection against encroaching vegetation, increasing canopy openness over their host plants. These differences in benefits among the ant partners of Cordia and Duroia are reflected in the effect of each ant species on host plant size, growth rate, and reproduction. The results of this study show how mutualistic ant partners can differ with respect to both the magnitude and type of benefits they provide to the same species of myrmecophytic host.

  7. Fast and flexible: argentine ants recruit from nearby trails.

    Directory of Open Access Journals (Sweden)

    Tatiana P Flanagan

    Full Text Available Argentine ants (Linepithema humile live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  8. Host ant independent oviposition in the parasitic butterfly Maculinea alcon

    DEFF Research Database (Denmark)

    Fürst, Matthias A; Nash, David Richard

    2010-01-01

    to host-ant nests and non-host-ant nests, and the number and position of eggs attached were assessed. Our results show no evidence for host-ant-based oviposition in M. alcon, but support an oviposition strategy based on plant characteristics. This suggests that careful management of host-ant distribution......Parasitic Maculinea alcon butterflies can only develop in nests of a subset of available Myrmica ant species, so female butterflies have been hypothesized to preferentially lay eggs on plants close to colonies of the correct host ants. Previous correlational investigations of host......-ant-dependent oviposition in this and other Maculinea species have, however, shown equivocal results, leading to a long-term controversy over support for this hypothesis. We therefore conducted a controlled field experiment to study the egg-laying behaviour of M. alcon. Matched potted Gentiana plants were set out close...

  9. Exploring with PAM: Prospecting ANTS Missions for Solar System Surveys

    Science.gov (United States)

    Clark, P. E.; Rilee, M. L.; Curtis, S. A.

    2003-01-01

    ANTS (Autonomous Nano-Technology Swarm), a large (1000 member) swarm of nano to picoclass (10 to 1 kg) totally autonomous spacecraft, are being developed as a NASA advanced mission concept. ANTS, based on a hierarchical insect social order, use an evolvable, self-similar, hierarchical neural system in which individual spacecraft represent the highest level nodes. ANTS uses swarm intelligence attained through collective, cooperative interactions of the nodes at all levels of the system. At the highest levels this can take the form of cooperative, collective behavior among the individual spacecraft in a very large constellation. The ANTS neural architecture is designed for totally autonomous operation of complex systems including spacecraft constellations. The ANTS (Autonomous Nano Technology Swarm) concept has a number of possible applications. A version of ANTS designed for surveying and determining the resource potential of the asteroid belt, called PAM (Prospecting ANTS Mission), is examined here.

  10. Fast and flexible: argentine ants recruit from nearby trails.

    Science.gov (United States)

    Flanagan, Tatiana P; Pinter-Wollman, Noa M; Moses, Melanie E; Gordon, Deborah M

    2013-01-01

    Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  11. Gallbladder leiomyoma in absence of immune system disorders: an unusual diagnosis Leiomioma de vesícula biliar en ausencia de patología del sistema inmune: un diagnóstico inusual

    Directory of Open Access Journals (Sweden)

    Juan José Segura-Sampedro

    2012-07-01

    Full Text Available Mesenchymal neoplasms of the gallbladder are rare and in particular leiomyomas of the gallbladder have been rarely reported, all of them in patients with immune system disorders. This is the first report in Spanish of a 23-year-old female patient with a gallbladder leiomyoma without associated immunodeficiency. The patient lacks a previous history of uterine leiomyoma or any other form of neoplasm. She refers several episodes of epygastralgia. A hydatic cyst led to an initial diagnosis and the gallbladder was removed by means of simple cholecystectomy. The abnormal macroscopic aspect of the sample prompted intraoperative biopsy which revealed a benign gallbladder angiomyoma. Subsequent immunohistochemical analysis of the resected sample yielded the diagnosis of intramural endocavitary leiomyoma negative for EBV and C-kit / CD-117. The patient has good general condition and remains asymptomatic 15 months after surgery.Las neoplasias mesenquimales de vesícula biliar son una patología muy poco frecuente, concretamente, son muy pocos los casos descritos de leiomioma de vesícula biliar y todos ellos diagnosticados en pacientes con enfermedades del sistema inmunitario. Se describe por primera vez en la literatura en lengua española el caso de un leiomioma vesicular en una mujer de 23 años sin compromiso inmunitario alguno. La paciente carece de historia de leiomioma uterino o cualquier otra neoplasia. Presenta una historia de epigastralgias de evolución. Se formuló un primer diagnóstico guiado por imagen de quiste hidatídico. La vesícula fue extirpada mediante colecistectomía simple. El aspecto macroscópico anormal motivó una biopsia intraoperatoria que fue informada como angiomioma vesicular benigno. El posterior estudio inmunohistoquímico de la pieza arrojó el diagnóstico de leiomioma intramural y endocavitario negativo para VEB y C-Kit / CD-117. La paciente presenta buen estado general y permanece asintomática 15 meses después de

  12. Using pleometrosis (multiple queens) and pupae transplantation to boost weaver ant (Oecophylla smaragdina) colony growth in ant nurseries

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Nielsen, Mogens Gissel; Peng, Renkang

    2011-01-01

    Weaver ants (Oecophylla spp.) are increasingly being used for biocontrol and are targeted for future production of insect protein in ant farms. An efficient production of live ant colonies may facilitate the utilization of these ants but the production of mature colonies is hampered by the long...... and no transplantation. Thus, in ant nurseries the use of multiple queens during nest founding as well as transplantation of pupae from foreign colonies may be utilised to decrease the time it takes to produce a colony ready for implementation....

  13. Developing Principal Instructional Leadership through Collaborative Networking

    Science.gov (United States)

    Cone, Mariah Bahar

    2010-01-01

    This study examines what occurs when principals of urban schools meet together to learn and improve their instructional leadership in collaborative principal networks designed to support, sustain, and provide ongoing principal capacity building. Principal leadership is considered second only to teaching in its ability to improve schools, yet few…

  14. 31 CFR 19.995 - Principal.

    Science.gov (United States)

    2010-07-01

    ... SUSPENSION (NONPROCUREMENT) Definitions § 19.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or supervisory... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Principal. 19.995 Section 19.995...

  15. 22 CFR 208.995 - Principal.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Principal. 208.995 Section 208.995 Foreign...) Definitions § 208.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or supervisory responsibilities related to a...

  16. 29 CFR 1471.995 - Principal.

    Science.gov (United States)

    2010-07-01

    ... SUSPENSION (NONPROCUREMENT) Definitions § 1471.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or... 29 Labor 4 2010-07-01 2010-07-01 false Principal. 1471.995 Section 1471.995 Labor Regulations...

  17. 21 CFR 1404.995 - Principal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Principal. 1404.995 Section 1404.995 Food and...) Definitions § 1404.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or supervisory responsibilities related to a...

  18. 22 CFR 1006.995 - Principal.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Principal. 1006.995 Section 1006.995 Foreign... § 1006.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or supervisory responsibilities related to a...

  19. 2 CFR 180.995 - Principal.

    Science.gov (United States)

    2010-01-01

    ... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false Principal. 180.995 Section 180.995 Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET GOVERNMENTWIDE GUIDANCE FOR GRANTS AND AGREEMENTS... § 180.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator...

  20. 34 CFR 85.995 - Principal.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Principal. 85.995 Section 85.995 Education Office of...) Definitions § 85.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or supervisory responsibilities related to a...

  1. 22 CFR 1508.995 - Principal.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Principal. 1508.995 Section 1508.995 Foreign...) Definitions § 1508.995 Principal. Principal means— (a) An officer, director, owner, partner, principal investigator, or other person within a participant with management or supervisory responsibilities related to a...

  2. Optic disc detection using ant colony optimization

    Science.gov (United States)

    Dias, Marcy A.; Monteiro, Fernando C.

    2012-09-01

    The retinal fundus images are used in the treatment and diagnosis of several eye diseases, such as diabetic retinopathy and glaucoma. This paper proposes a new method to detect the optic disc (OD) automatically, due to the fact that the knowledge of the OD location is essential to the automatic analysis of retinal images. Ant Colony Optimization (ACO) is an optimization algorithm inspired by the foraging behaviour of some ant species that has been applied in image processing for edge detection. Recently, the ACO was used in fundus images to detect edges, and therefore, to segment the OD and other anatomical retinal structures. We present an algorithm for the detection of OD in the retina which takes advantage of the Gabor wavelet transform, entropy and ACO algorithm. Forty images of the retina from DRIVE database were used to evaluate the performance of our method.

  3. A global database of ant species abundances

    Czech Academy of Sciences Publication Activity Database

    Gibb, H.; Dunn, R. R.; Sanders, N. J.; Grossman, B. F.; Photakis, M.; Abril, S.; Agosti, D.; Andersen, A. N.; Angulo, E.; Armbrecht, I.; Arnan, X.; Baccaro, F. B.; Bishop, T. R.; Boulay, R.; Brühl, C.; Castracani, C.; Cerdá, X.; Del Toro, I.; Delsinne, T.; Diaz, M.; Donoso, D. A.; Ellison, A. M.; Enríquez, M. L.; Fayle, Tom Maurice; Feener, D. H.; Fisher, B. L.; Fisher, R. N.; Fitzpatrick, M. C.; Gómez, C.; Gotelli, N. J.; Gove, A.; Grasso, D. A.; Groc, S.; Guenard, B.; Gunawardene, N.; Heterick, B.; Hoffmann, B.; Janda, Milan; Jenkins, C.; Kaspari, M.; Klimeš, Petr; Lach, L.; Laeger, T.; Lattke, J.; Leponce, M.; Lessard, J.-P.; Longino, J.; Lucky, A.; Luke, S. H.; Majer, J.; McGlynn, T. P.; Menke, S.; Mezger, D.; Mori, A.; Moses, Jimmy; Munyai, T. C.; Pacheco, R.; Paknia, O.; Pearce-Duvet, J.; Pfeiffer, M.; Philpott, S. M.; Resasco, J.; Retana, J.; Silva, R. R.; Sorger, M. D.; Souza, J.; Suarez, A.; Tista, M.; Vasconcelos, H. L.; Vonshak, M.; Weisser, M. D.; Yates, M.; Parr, C. L.

    2017-01-01

    Roč. 98, č. 3 (2017), s. 883-884 ISSN 0012-9658 R&D Projects: GA ČR GB14-36098G; GA ČR GAP505/12/2467; GA ČR GPP505/12/P875 Institutional support: RVO:60077344 Keywords : abundance * ants * database Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.809, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/ecy.1682/abstract

  4. Public goods dilemma in asexual ant societies

    OpenAIRE

    Dobata, Shigeto; Tsuji, Kazuki

    2013-01-01

    This study reports experimental evidence for the “public goods dilemma” between cooperators and cheaters in an asexual ant society, in which cheating is always more rewarding for individuals but cooperation at the cost of individual fitness leads to better performance of groups. Although this dilemma provides the basic principle of social evolution, its experimental demonstration with underlying genetics and fitness evaluation for both cooperators and cheaters still lacks in societies other t...

  5. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  6. Acurácia diagnóstica do espessamento ecogênico periportal à ultra-sonografia e da histopatologia no diagnóstico diferencial da atresia biliar Accuracy of echogenic periportal enlargement image in ultrasonographic exams and histopathology in differential diagnosis of biliary atresia

    Directory of Open Access Journals (Sweden)

    Mariza L. V. Roquete

    2008-08-01

    Full Text Available OBJETIVOS: Definir a sensibilidade, especificidade e a acurácia do espessamento ecogênico periportal à ultra-sonografia e da histopatologia hepática, isolados ou em conjunto, na distinção diagnóstica entre atresia biliar e as colestases intra-hepáticas. MÉTODOS: Trata-se de estudo retrospectivo realizado entre janeiro de 1990 e dezembro de 2004. Foram analisados 51 casos de atresia biliar e 45 com colestase intra-hepática. A histopatologia foi realizada por uma patologista de forma cega. O espessamento ecogênico periportal foi pesquisado na ultra-sonografia como único sinal diagnóstico de atresia biliar. Foram calculados os índices de sensibilidade, especificidade e acurácia do espessamento ecogênico periportal e da histologia isoladamente ou associados. O padrão-ouro utilizado para o diagnóstico de atresia biliar foi o aspecto da via biliar extra-hepática à laparotomia. RESULTADOS: O espessamento ecogênico periportal revelou sensibilidade de 49%, especificidade de 100% e acurácia de 72,5%. A histopatologia compatível com obstrução biliar extra-hepática conferiu sensibilidade de 90,2%, especificidade de 84,6% e acurácia de 87,8%. O espessamento ecogênico periportal e a histopatologia isolados ou associados proporcionaram sensibilidade de 93,2%, especificidade de 85,7% e acurácia de 90,3%. CONCLUSÕES: A evidência do espessamento ecogênico periportal na ultra-sonografia é indicação de laparotomia. Se o espessamento ecogênico periportal é negativo, está indicada a biopsia hepática; se a histopatologia revelar sinais de atresia biliar, impõe-se a laparotomia exploradora. Nos casos de espessamento ecogênico periportal negativo com histopatologia de hepatite neonatal ou de outras colestases intra-hepáticas, recomenda-se o acompanhamento ou o tratamento clínico conforme o diagnóstico.OBJECTIVES: To define the sensitivity, specificity and accuracy of the ultrasound triangular cord sign and hepatic

  7. Nutritional status of patients with biliary atresia and autoimmune hepatitis related to serum levels of vitamins A, D and E Estado nutricional de pacientes com atresia biliar e hepatite autoimune e relação com os níveis séricos de vitaminas A, D e E

    Directory of Open Access Journals (Sweden)

    Margareth L. G. Saron

    2009-03-01

    Full Text Available CONTEXT: Chronic liver disease may induce to malabsorption of lipids and fat-soluble vitamins, leading to injury of nutritional status. OBJECTIVES: To evaluate the nutritional status of pediatric-age patients with autoimmune hepatitis and biliary atresia related to serum levels of vitamins A, D and E and the disease severity. METHODS: This controlled transverse study, evaluated the patients with autoimmune hepatitis and biliary atresia and a reference group paired by sex and age. The patients underwent anthropometric evaluation, alimentary inquiry and determination of serum levels of vitamins A, D and E by high performance liquid chromatography. The Mann-Whitney test, Spearman correlation coefficients and variance analysis (ANOVA were utilized for data treatment, regarding significant difference if PCONTEXTO: As doenças hepáticas crônicas podem induzir à má absorção de lipídios e vitaminas lipossolúveis e levar ao comprometimento do estado nutricional. OBJETIVOS: Avaliar o estado nutricional e relacionar com os níveis séricos de vitaminas (A, D e E e a gravidade da doença em pacientes com atresia biliar e hepatite autoimune na faixa etária pediátrica. MÉTODOS: O estudo foi transversal controlado e foram avaliados os pacientes com hepatite autoimune e atresia biliar e um grupo controle pareado por sexo e idade. Foi realizada avaliação antropométrica, aplicação do inquérito alimentar e determinação dos níveis séricos das vitaminas A, D e E pela técnica de cromatografia líquida de alta eficiência. Foram empregados os testes de Mann-Whitney, o coeficiente de correlação de Spearman e análise de variância (ANOVA, sendo considerada diferença significativa se P<0,05. RESULTADOS: O déficit nutricional mais grave foi observado nos pacientes com atresia biliar, principalmente com colestase. Em relação às vitaminas, no grupo controle, constatou-se que os níveis séricos das vitaminas A e E variaram com a idade. Os n

  8. Liver histological, portal flow and plasmatic nitric oxide alterations caused by biliary obstruction and drainage in rats Alterações histológicas, do fluxo portal e do óxido nítrico plasmático em ratos submetidos à obstrução/desobstrução biliar

    Directory of Open Access Journals (Sweden)

    Miguel Angel Dias

    2008-01-01

    Full Text Available PURPOSE: To evaluate liver alterations caused by biliary obstruction and drainage. METHODS: Thirty-nine male Wistar rats were randomly distributed in 4 groups: BO (n=18 bile duct ligation for 20 days, with a periodic evaluation of liver histological alterations, Doppler echography portal flow and measurements of NO and malondialdehyde (MDA; BO/DB (n=13 bile duct occlusion for 20 days followed by biliary drainage by choledochoduodenal anastomosis, 5 days follow-up, same BO group parameters evaluations; group CED (n=4 sham operation and portal flow evaluation trough 20 days; CHB (n=4 sham operation, with hepatic biopsy on 25th day and followed-up trough 25 days, by the same parameters of group BO, with exception of portal flow. Direct bilirubin (DB and alkaline phosphatase (AP were evaluated in the group BO, BO/DB and CHB. RESULTS: The bile duct ligation led to an increase of DB and AP, development of liver histological alterations, reduction of portal flow and increase of plasmatic NO and of MDA levels. The bile duct clearing resulted in a reduction of DB, AP, NO, MDA histological alterations and increase of portal flow. CONCLUSION: The biliary occlusion resulted in cholestasis and portal flow reduction, besides the increase of plasmatic NO and of hepatic MDA levels, and histological liver alterations, with a tendency of normalization after the bile duct clearing.OBJETIVO: Avaliar alterações hepáticas resultantes do processo de obstrução/desobstrução biliar. MÉTODOS: Trinta e nove ratos Wistar foram distribuídos aleatoriamente em 4 grupos: OB (n=18, oclusão biliar, seguimento de 20 dias, avaliação das alterações histológicas hepáticas, do fluxo portal e dosagens de NO e de malondialdeído (MDA; grupo OB/DB (n=13 oclusão biliar por 20 dias seguida de desobstrução biliar por anastomose colédoco-duodenal, seguimento por 5 dias e avaliação dos mesmos parâmetros do grupo BO; grupo CED (n=4 operação simulada, avaliação do

  9. Precision Rescue Behavior in North American Ants

    Directory of Open Access Journals (Sweden)

    Katherine Taylor

    2013-07-01

    Full Text Available Altruistic behavior, in which one individual provides aid to another at some cost to itself, is well documented. However, some species engage in a form of altruism, called rescue, that places the altruist in immediate danger. Here we investigate one such example, namely rescuing victims captured by predators. In a field experiment with two North American ant species, Tetramorium sp. E and Prenolepis imparis, individuals were held in artificial snares simulating capture. T. sp. E, but not P. imparis, exhibited digging, pulling, and snare biting, the latter precisely targeted to the object binding the victim. These results are the first to document precision rescue in a North American ant species; moreover, unlike rescue in other ants, T. sp. E rescues conspecifics from different colonies, mirroring their atypical social behavior, namely the lack of aggression between non-nestmate (heterocolonial conspecifics. In a second, observational study designed to demonstrate rescue from an actual predator, T. sp. E victims were dropped into an antlion's pit and the behavior of a single rescuer was observed. Results showed that T. sp. E not only attempted to release the victim, but also risked attacking the predator, suggesting that precision rescue may play an important role in this species' antipredator behavior.

  10. El periodista, ante la espiral de silencio

    Directory of Open Access Journals (Sweden)

    Dr. Fermín Galindo Arranz

    1998-01-01

    Full Text Available La percepción de la profesión periodística y de su influencia cambia mucho a lo largo del tiempo, de las coyunturas históricas y de los diferentes países y sociedades en los que desempeñan su labor. En un contexto mundial, la gravedad de las situaciones de riesgo periodístico se encuadran en situaciones políticas, económicas o sociales también conflictivas; es entonces cuando se suele reproducir con facilidad en la opinión pública el fenómeno de la espiral del silencio, ante el que inevitablemente se sitúa el periodista. Por definición, el trabajo del periodista consiste en ser portavoz de las novedades que se producen, en dar informaciones y emitir opiniones en la esfera pública, se tiene que situar, por tanto, de forma individual y notoriamente pública ante los fenómenos de espiral de silencio que puedan producirse en la opinión pública. Antonio Tabucchi nos presenta en su novela "Sostiene Pereira" un ejemplo magnífico del dilema del periodista ante este tipo de situaciones.

  11. Recognition of social identity in ants

    Directory of Open Access Journals (Sweden)

    Nick eBos

    2012-03-01

    Full Text Available Recognizing the identity of others, from the individual to the group level, is a hallmark of society. Ants, and other social insects, have evolved advanced societies characterized by efficient social recognition systems. Colony identity is mediated by colony specific signature mixtures, a blend of hydrocarbons present on the cuticle of every individual (the label. Recognition occurs when an ant encounters another individual, and compares the label it perceives to an internal representation of its own colony odor (the template. A mismatch between label and template leads to rejection of the encountered individual. Although advances have been made in our understanding of how the label is produced and acquired, contradictory evidence exists about information processing of recognition cues. Here, we review the literature on template acquisition in ants and address how and when the template is formed, where in the nervous system it is localized, and the possible role of learning. We combine seemingly contradictory evidence in to a novel, parsimonious theory for the information processing of nestmate recognition cues.

  12. Mating with stressed males increases the fitness of ant queens.

    Directory of Open Access Journals (Sweden)

    Alexandra Schrempf

    Full Text Available BACKGROUND: According to sexual conflict theory, males can increase their own fitness by transferring substances during copulation that increase the short-term fecundity of their mating partners at the cost of the future life expectancy and re-mating capability of the latter. In contrast, sexual cooperation is expected in social insects. Mating indeed positively affects life span and fecundity of young queens of the male-polymorphic ant Cardiocondyla obscurior, even though males neither provide nuptial gifts nor any other care but leave their mates immediately after copulation and die shortly thereafter. PRINCIPAL FINDINGS: Here, we show that mating with winged disperser males has a significantly stronger impact on life span and reproductive success of young queens of C. obscurior than mating with wingless fighter males. CONCLUSIONS: Winged males are reared mostly under stressful environmental conditions, which force young queens to disperse and found their own societies independently. In contrast, queens that mate with wingless males under favourable conditions usually start reproducing in the safety of the established maternal nest. Our study suggests that males of C. obscurior have evolved mechanisms to posthumously assist young queens during colony founding under adverse ecological conditions.

  13. The invasive ant, Solenopsis invicta, reduces herpetofauna richness and abundance

    Science.gov (United States)

    Allen, Craig R.; Birge, Hannah E.; Slater, J.; Wiggers, E.

    2017-01-01

    Amphibians and reptiles are declining globally. One potential cause of this decline includes impacts resulting from co-occurrence with non-native red imported fire ant, Solenopsis invicta. Although a growing body of anecdotal and observational evidence from laboratory experiments supports this hypothesis, there remains a lack of field scale manipulations testing the effect of fire ants on reptile and amphibian communities. We addressed this gap by measuring reptile and amphibian (“herpetofauna”) community response to successful fire ant reductions over the course of 2 years following hydramethylnon application to five 100–200 ha plots in southeastern coastal South Carolina. By assessing changes in relative abundance and species richness of herpetofauna in response to fire ant reductions, we were able to assess whether some species were particularly vulnerable to fire ant presence, and whether this sensitivity manifested at the community level. We found that herpetofauna abundance and species richness responded positively to fire ant reductions. Our results document that even moderate populations of red imported fire ants decrease both the abundance and diversity of herpetofauna. Given global herpetofauna population declines and continued spread of fire ants, there is urgency to understand the impacts of fire ants beyond anecdotal and singles species studies. Our results provides the first community level investigation addressing these dynamics, by manipulating fire ant abundance to reveal a response in herpetofauna species abundance and richness.

  14. Principal chiral model on superspheres

    International Nuclear Information System (INIS)

    Mitev, V.; Schomerus, V.; Quella, T.

    2008-09-01

    We investigate the spectrum of the principal chiral model (PCM) on odd-dimensional superspheres as a function of the curvature radius R. For volume-filling branes on S 3 vertical stroke 2 , we compute the exact boundary spectrum as a function of R. The extension to higher dimensional superspheres is discussed, but not carried out in detail. Our results provide very convincing evidence in favor of the strong-weak coupling duality between supersphere PCMs and OSP(2S+2 vertical stroke 2S) Gross-Neveu models that was recently conjectured by Candu and Saleur. (orig.)

  15. Predaceous ants, beach replenishment, and nest placement by sea turtles.

    Science.gov (United States)

    Wetterer, James K; Wood, Lawrence D; Johnson, Chris; Krahe, Holly; Fitchett, Stephanie

    2007-10-01

    Ants known for attacking and killing hatchling birds and reptiles include the red imported fire ant (Solenopsis invicta Buren), tropical fire ant [Solenopsis geminata (Fabr.)], and little fire ant [Wasmannia auropunctata (Roger)]. We tested whether sea turtle nest placement influenced exposure to predaceous ants. In 2000 and 2001, we surveyed ants along a Florida beach where green turtles (Chelonia mydas L.), leatherbacks (Dermochelys coriacea Vandelli), and loggerheads (Caretta caretta L.) nest. Part of the beach was artificially replenished between our two surveys. As a result, mean beach width experienced by nesting turtles differed greatly between the two nesting seasons. We surveyed 1,548 sea turtle nests (2000: 909 nests; 2001: 639 nests) and found 22 ant species. S. invicta was by far the most common species (on 431 nests); S. geminata and W. auropunctata were uncommon (on 3 and 16 nests, respectively). In 2000, 62.5% of nests had ants present (35.9% with S. invicta), but in 2001, only 30.5% of the nests had ants present (16.4% with S. invicta). Turtle nests closer to dune vegetation had significantly greater exposure to ants. Differences in ant presence on turtle nests between years and among turtle species were closely related to differences in nest placement relative to dune vegetation. Beach replenishment significantly lowered exposure of nests to ants because on the wider beaches turtles nested farther from the dune vegetation. Selective pressures on nesting sea turtles are altered both by the presence of predaceous ants and the practice of beach replenishment.

  16. Chemically armed mercenary ants protect fungus-farming societies

    Science.gov (United States)

    Adams, Rachelle M. M.; Liberti, Joanito; Illum, Anders A.; Jones, Tappey H.; Nash, David R.; Boomsma, Jacobus J.

    2013-01-01

    The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit from their costly guest ants behaving as a functional soldier caste to meet lethal threats from agro-predator raiders. The fundamentally different life histories of the agro-predators and guest ants appear to facilitate their coexistence in a negative frequency-dependent manner. Because a guest ant colony is committed for life to a single host colony, the guests would harm their own interests by not defending the host that they continue to exploit. This conditional mutualism is analogous to chronic sickle cell anemia enhancing the resistance to malaria and to episodes in human history when mercenary city defenders offered either net benefits or imposed net costs, depending on the level of threat from invading armies. PMID:24019482

  17. Chemically armed mercenary ants protect fungus-farming societies.

    Science.gov (United States)

    Adams, Rachelle M M; Liberti, Joanito; Illum, Anders A; Jones, Tappey H; Nash, David R; Boomsma, Jacobus J

    2013-09-24

    The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit from their costly guest ants behaving as a functional soldier caste to meet lethal threats from agro-predator raiders. The fundamentally different life histories of the agro-predators and guest ants appear to facilitate their coexistence in a negative frequency-dependent manner. Because a guest ant colony is committed for life to a single host colony, the guests would harm their own interests by not defending the host that they continue to exploit. This conditional mutualism is analogous to chronic sickle cell anemia enhancing the resistance to malaria and to episodes in human history when mercenary city defenders offered either net benefits or imposed net costs, depending on the level of threat from invading armies.

  18. When invasive ants meet: effects of outbreeding on queen performance in the tramp ant Cardiocondyla itsukii.

    Science.gov (United States)

    Heinze, Jürgen; Frohschammer, Sabine; Bernadou, Abel

    2017-08-18

    Most disturbed habitats in the tropics and subtropics harbor numerous species of invasive ants, and occasionally the same species has been introduced repeatedly from multiple geographical sources. We examined how experimental crossbreeding between sexuals from different populations affects the fitness of queens of the tramp ant Cardiocondyla itsukii, which is widely distributed in Asia and the Pacific Islands. Eggs laid by queens that mated with nestmate males had a higher hatching rate than eggs laid by queens mated to males from neighboring (Hawaii × Kauai) or distant introduced populations (Hawaii/Kauai × Okinawa). Furthermore, inbreeding queens had a longer lifespan and produced a less female-biased offspring sex ratio than queens from allopatric mating. This suggests that the genetic divergence between different source populations may already be so large that in case of multiple invasions eventual crossbreeding might negatively affect the fitness of tramp ants. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  19. Diagnostic yield of brush cytology for biliary stenosis during ERCP Rentabilidad diagnóstica de la citología por cepillado de las estenosis biliares durante la CPRE

    Directory of Open Access Journals (Sweden)

    R. Temiño López-Jurado

    2009-06-01

    Full Text Available Aim: to evaluate the diagnostic yield of brush cytology for biliary strictures detected on ERCP when a systematic approach is used. Patients and methods: data on 62 consecutive patients with a biliary stricture on ERCP were collected. Cytological samples were processed immediately after brushing in the endoscopy room, and all were analyzed by the same pathologist. For the statistical analysis specimens were classified as positive, negative, suspicious for malignancy (presence of atypias, and unsatisfactory for evaluation. Final diagnosis was based on either histopathologic (surgery or biopsies by other techniques or clinical/radiographic diagnosis. Results: a total of 71 cytological specimens were included. Definite diagnosis was malignancy in 49 samples, and benign stricture in 22. Three samples were excluded because of insufficient material or processing artifacts. The sensitivity of biliary brushing was 62% (95% CI 0.47-0.77, specificity was 100%, positive predictive value was 100%, and negative predictive value was 58% (95% CI 0.43-0.75. When suspicious samples were included as malignant, sensitivity was 67% (95% CI 0.54-0.81 without changes in the remaining parameters. Eight patients underwent more than one ERCP. Repeated brush cytology exams in these patients yielded a definitive diagnosis in every case. Conclusions: brush cytology has intermediate sensitivity with a high specificity. A systematic approach with a dedicated pathologist and the inclusion of significant atypias as malignant results improves sensitivity. Due to its simplicity brush cytology should be performed in all cases of biliary strictures detected on ERCP, and in case of repeated ERCPs additional cytology brushings are recommended.Objetivo: evaluar la rentabilidad de la citología por cepillado de las estenosis biliares diagnosticadas por CPRE cuando se aplica una metodología sistemática. Pacientes y métodos: se recogieron muestras de 62 pacientes consecutivos con

  20. Interpretable functional principal component analysis.

    Science.gov (United States)

    Lin, Zhenhua; Wang, Liangliang; Cao, Jiguo

    2016-09-01

    Functional principal component analysis (FPCA) is a popular approach to explore major sources of variation in a sample of random curves. These major sources of variation are represented by functional principal components (FPCs). The intervals where the values of FPCs are significant are interpreted as where sample curves have major variations. However, these intervals are often hard for naïve users to identify, because of the vague definition of "significant values". In this article, we develop a novel penalty-based method to derive FPCs that are only nonzero precisely in the intervals where the values of FPCs are significant, whence the derived FPCs possess better interpretability than the FPCs derived from existing methods. To compute the proposed FPCs, we devise an efficient algorithm based on projection deflation techniques. We show that the proposed interpretable FPCs are strongly consistent and asymptotically normal under mild conditions. Simulation studies confirm that with a competitive performance in explaining variations of sample curves, the proposed FPCs are more interpretable than the traditional counterparts. This advantage is demonstrated by analyzing two real datasets, namely, electroencephalography data and Canadian weather data. © 2015, The International Biometric Society.

  1. Food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions in an arid environment

    Science.gov (United States)

    Flores-Flores, Rocío Vianey; Aguirre, Armando; Anjos, Diego V.; Neves, Frederico S.; Campos, Ricardo I.; Dáttilo, Wesley

    2018-02-01

    In this study, we conducted a series of experiments in a population of Vachellia constricta (Fabaceae) in the arid Tehuacan-Cuicatláan valley, Mexico, in order to evaluate if the food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions. Using an experiment with artificial nectaries, we observed that ants foraging on food sources with higher concentration of sugar are quicker in finding and attacking potential herbivorous insects. More specifically, we found that the same ant species may increase their defence effectiveness according to the quality of food available. These findings indicate that ant effectiveness in plant protection is context-dependent and may vary according to specific individual characteristics of plants. In addition, we showed that competitively superior ant species tend to dominate plants in periods with high nectar activity, emphasizing the role of the dominance hierarchy structuring ant-plant interactions. However, when high sugar food sources were experimentally available ad libitum, the nocturnal and competitively superior ant species, Camponotus atriceps, did not dominate the artificial nectaries during the day possibly due to limitation of its thermal tolerance. Therefore, temporal niche partitioning may be allowing the coexistence of two dominant ant species (Camponotus rubritorax during the day and C. atriceps at night) on V. constricta. Our findings indicate that the quality of the food source, and temporal shifts in ant dominance are key factors which structure the biotic plant defences in an arid environment.

  2. Female Traditional Principals and Co-Principals: Experiences of Role Conflict and Job Satisfaction

    Science.gov (United States)

    Eckman, Ellen Wexler; Kelber, Sheryl Talcott

    2010-01-01

    This paper presents a secondary analysis of survey data focusing on role conflict and job satisfaction of 102 female principals. Data were collected from 51 female traditional principals and 51 female co-principals. By examining the traditional and co-principal leadership models as experienced by female principals, this paper addresses the impact…

  3. Variabilidad temporal de la fauna acompañante del camarón Farfantepenaeus notialis en el Golfo de Ana María, Cuba

    OpenAIRE

    Valdés, E.; Villafuerte, V.; Domínguez, H.; Pérez, A.

    2011-01-01

    Se analizó la diversidad de la fauna acompañante del camarón en la pesquería del Golfo de Ana María (plataforma suroriental cubana), en términos de la variabilidad temporal de los grupos taxonómicos que la integran y la abundancia relativa de las especies presentes, en particular de la ictiofauna. En el período 2002-2009, los peces fueron el principal integrante de la fauna acompañante del camarón en 82 %, seguido en orden por los crustáceos, moluscos, poríferos y equinodermos con...

  4. Just follow your nose: homing by olfactory cues in ants.

    Science.gov (United States)

    Steck, Kathrin

    2012-04-01

    How is an ant-equipped with a brain that barely exceeds the size of a pinhead-capable of achieving navigational marvels? Even though evidences suggest that navigation is a multimodal process, ants heavily depend on olfactory cues-of pheromonal and non-pheromonal nature-for foraging and orientation. Recent studies have directed their attention to the efficiency of pheromone trail networks. Advances in neurophysiological techniques make it possible to investigate trail pheromone processing in the ant's brain. In addition to relying on pheromone odours, ants also make use of volatiles emanating from the nest surroundings. Deposited in the vicinity of the nest, these home-range markings help the ants to home after a foraging run. Furthermore, olfactory landmarks associated with the nest enhance ants' homing abilities. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Ant tending influences soldier production in a social aphid.

    Science.gov (United States)

    Shingleton, A W; Foster, W A

    2000-09-22

    The aphid Pseudoregma sundanica (Van der Goot) (Homoptera: Aphididae) has two defence strategies. It is obligatorily tended by various species of ant and also produces sterile soldiers. We investigated how they allocate their investment in these two strategies. We measured the size, number of soldiers, number and species of tending ant, and number and species of predators in P. sundanica populations. We found that the level of ant tending correlated negatively with soldier investment in P. sundanica. The species of tending ant also influenced soldier investment. We excluded ants from aphid populations and recorded changes in population size and structure over four weeks. Ant exclusion led to population decline and extinction. At the same time, surviving populations showed a significant increase in soldier investment. The data demonstrate that social aphids can adjust their investment in soldiers in direct response to environmental change.

  6. Consuming fire ants reduces northern bobwhite survival and weight gain

    Science.gov (United States)

    Myers, P.E.; Allen, Craig R.; Birge, Hannah E.

    2014-01-01

    Northern bobwhite quail, Colinus virginianus (L.) (Galliformes: Odontophoridae), population declines are well documented, but pinpointing the reasons for these decreases has proven elusive. Bobwhite population declines are attributed primarily to loss of habitat and land use changes. This, however, does not entirely explain population declines in areas intensively managed for bobwhites. Although previous research demonstrates the negative impact of red imported fire ant (Solenopsis invicta Buren) (Hymenoptera: Formicidae) on northern bobwhites, the mechanisms underlying this effect are largely unknown. To meet the protein demands of early growth and development, bobwhite chicks predominantly consume small insects, of which ants are a substantial proportion. Fire ants alter ant community dynamics by often reducing native ant diversity and abundance while concurrently increasing the abundance of individuals. Fire ants have negative effects on chicks, but they are also a large potential protein source, making it difficult to disentangle their net effect on bobwhite chicks. To help investigate these effects, we conducted a laboratory experiment to understand (1) whether or not bobwhites consume fire ants, and (2) how the benefits of this consumption compare to the deleterious impacts of bobwhite chick exposure to fire ants. Sixty bobwhite chicks were separated into two groups of 30; one group was provided with starter feed only and the second group was provided with feed and fire ants. Bobwhite chicks were observed feeding on fire ants. Chicks that fed on fire ants had reduced survival and weight gain. Our results show that, while fire ants increase potential food sources for northern bobwhite, their net effect on bobwhite chicks is deleterious. This information will help inform land managers and commercial bobwhite rearing operations.

  7. Cercomacra and related antbirds (Aves, Formicariidae as army ant followers

    Directory of Open Access Journals (Sweden)

    Edwin O. Willis

    1984-01-01

    Full Text Available Cercomacra and Schistocichla antbirds (Formicariidae favor dense foliage and seldom follow army ants for flushed prey, since the ants move through open forest understory as well as through dense zones. Two other lineages, the Drymophila-Hypocnemis lineage (of dense woodland understory and the Formicivora lineage (of dense bushes in dry or semiopen zones, also cannot follow ants regularly through open forest understory.

  8. Do herbivores eavesdrop on ant chemical communication to avoid predation?

    Directory of Open Access Journals (Sweden)

    David J Gonthier

    Full Text Available Strong effects of predator chemical cues on prey are common in aquatic and marine ecosystems, but are thought to be rare in terrestrial systems and specifically for arthropods. For ants, herbivores are hypothesized to eavesdrop on ant chemical communication and thereby avoid predation or confrontation. Here I tested the effect of ant chemical cues on herbivore choice and herbivory. Using Margaridisa sp. flea beetles and leaves from the host tree (Conostegia xalapensis, I performed paired-leaf choice feeding experiments. Coating leaves with crushed ant liquids (Azteca instabilis, exposing leaves to ant patrolling prior to choice tests (A. instabilis and Camponotus textor and comparing leaves from trees with and without A. instabilis nests resulted in more herbivores and herbivory on control (no ant-treatment relative to ant-treatment leaves. In contrast to A. instabilis and C. textor, leaves previously patrolled by Solenopsis geminata had no difference in beetle number and damage compared to control leaves. Altering the time A. instabilis patrolled treatment leaves prior to choice tests (0-, 5-, 30-, 90-, 180-min. revealed treatment effects were only statistically significant after 90- and 180-min. of prior leaf exposure. This study suggests, for two ecologically important and taxonomically diverse genera (Azteca and Camponotus, ant chemical cues have important effects on herbivores and that these effects may be widespread across the ant family. It suggests that the effect of chemical cues on herbivores may only appear after substantial previous ant activity has occurred on plant tissues. Furthermore, it supports the hypothesis that herbivores use ant chemical communication to avoid predation or confrontation with ants.

  9. A Theoretic Basis for IS? The Contribution of ANT

    Directory of Open Access Journals (Sweden)

    Jim Underwood

    2002-11-01

    Full Text Available Representation is a key issue of IS design and operation that is often ignored. Actor-network theory (ANT, a semiotic theory of stakeholders, provides a way of dealing with representation. Combining aspects of ANT and Foucault's discourse theory allows us to include concepts as actors and promises a flexible and durable foundation for IS practice, but ANT itself indicates that the search for a purely theoretical foundation for IS is misguided.

  10. On Bayesian Principal Component Analysis

    Czech Academy of Sciences Publication Activity Database

    Šmídl, Václav; Quinn, A.

    2007-01-01

    Roč. 51, č. 9 (2007), s. 4101-4123 ISSN 0167-9473 R&D Projects: GA MŠk(CZ) 1M0572 Institutional research plan: CEZ:AV0Z10750506 Keywords : Principal component analysis ( PCA ) * Variational bayes (VB) * von-Mises–Fisher distribution Subject RIV: BC - Control Systems Theory Impact factor: 1.029, year: 2007 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V8V-4MYD60N-6&_user=10&_coverDate=05%2F15%2F2007&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b8ea629d48df926fe18f9e5724c9003a

  11. Insecticide transfer efficiency and lethal load in Argentine ants

    Energy Technology Data Exchange (ETDEWEB)

    Hooper-Bui, L.M. [Department of Environmental Science, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Entomology, University of California, Riverside, CA 92521 (United States); Kwok, E.S.C. [Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521 (United States); Buchholz, B.A., E-mail: buchholz2@llnl.gov [Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States); Rust, M.K. [Department of Entomology, University of California, Riverside, CA 92521 (United States); Eastmond, D.A. [Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521 (United States); Vogel, J.S. [Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

    2015-10-15

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of {sup 14}C-sucrose, {sup 14}C-hydramethylnon, and {sup 14}C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  12. Improved Ant Colony Clustering Algorithm and Its Performance Study

    Science.gov (United States)

    Gao, Wei

    2016-01-01

    Clustering analysis is used in many disciplines and applications; it is an important tool that descriptively identifies homogeneous groups of objects based on attribute values. The ant colony clustering algorithm is a swarm-intelligent method used for clustering problems that is inspired by the behavior of ant colonies that cluster their corpses and sort their larvae. A new abstraction ant colony clustering algorithm using a data combination mechanism is proposed to improve the computational efficiency and accuracy of the ant colony clustering algorithm. The abstraction ant colony clustering algorithm is used to cluster benchmark problems, and its performance is compared with the ant colony clustering algorithm and other methods used in existing literature. Based on similar computational difficulties and complexities, the results show that the abstraction ant colony clustering algorithm produces results that are not only more accurate but also more efficiently determined than the ant colony clustering algorithm and the other methods. Thus, the abstraction ant colony clustering algorithm can be used for efficient multivariate data clustering. PMID:26839533

  13. Insecticide transfer efficiency and lethal load in Argentine ants

    International Nuclear Information System (INIS)

    Hooper-Bui, L.M.; Kwok, E.S.C.; Buchholz, B.A.; Rust, M.K.; Eastmond, D.A.; Vogel, J.S.

    2015-01-01

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14 C-sucrose, 14 C-hydramethylnon, and 14 C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  14. Disease dynamics in a specialized parasite of ant societies

    DEFF Research Database (Denmark)

    Andersen, Sandra Breum; Ferrari, Matthew; Evans, Harry C.

    2012-01-01

    Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade......-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests...

  15. Signals can trump rewards in attracting seed-dispersing ants.

    Directory of Open Access Journals (Sweden)

    Kyle M Turner

    Full Text Available Both rewards and signals are important in mutualisms. In myrmecochory, or seed dispersal by ants, the benefits to plants are relatively well studied, but less is known about why ants pick up and move seeds. We examined seed dispersal by the ant Aphaenogaster rudis of four co-occurring species of plants, and tested whether morphology, chemical signaling, or the nutritional quality of fatty seed appendages called elaiosomes influenced dispersal rates. In removal trials, ants quickly collected diaspores (seeds plus elaiosomes of Asarum canadense, Trillium grandiflorum, and Sanguinaria canadensis, but largely neglected those of T. erectum. This discrepancy was not explained by differences in the bulk cost-benefit ratio, as assessed by the ratio of seed to elaiosome mass. We also provisioned colonies with diaspores from one of these four plant species or no diaspores as a control. Colonies performed best when fed S. canadensis diaspores, worst when fed T. grandiflorum, and intermediately when fed A. canadense, T. erectum, or no diaspores. Thus, the nutritional rewards in elaiosomes affected colony performance, but did not completely predict seed removal. Instead, high levels of oleic acid in T. grandiflorum elaiosomes may explain why ants disperse these diaspores even though they reduce ant colony performance. We show for the first time that different elaiosome-bearing plants provide rewards of different quality to ant colonies, but also that ants appear unable to accurately assess reward quality when encountering seeds. Instead, we suggest that signals can trump rewards as attractants of ants to seeds.

  16. Principals: Learn P.R. Survival Skills.

    Science.gov (United States)

    Reep, Beverly B.

    1988-01-01

    School building level public relations depends on the principal or vice principal. Strategies designed to enhance school public relations programs include linking school and community, working with the press, and keeping morale high inside the school. (MLF)

  17. The evolution of invasiveness in garden ants.

    Directory of Open Access Journals (Sweden)

    Sylvia Cremer

    Full Text Available It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects.

  18. The Evolution of Invasiveness in Garden Ants

    Science.gov (United States)

    Cremer, Sylvia; Ugelvig, Line V.; Drijfhout, Falko P.; Schlick-Steiner, Birgit C.; Steiner, Florian M.; Seifert, Bernhard; Hughes, David P.; Schulz, Andreas; Petersen, Klaus S.; Konrad, Heino; Stauffer, Christian; Kiran, Kadri; Espadaler, Xavier; d'Ettorre, Patrizia; Aktaç, Nihat; Eilenberg, Jørgen; Jones, Graeme R.; Nash, David R.; Pedersen, Jes S.; Boomsma, Jacobus J.

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects. PMID:19050762

  19. [Syagrus romanzoffiana (Arecaceae) seed utilization by ants in a secondary forest in South Brazil].

    Science.gov (United States)

    Silva, Fernanda R; Begnini, Romualdo M; Klier, Vinícius A; Scherer, Karla Z; Lopes, Benedito C; Castellani, Tânia T

    2009-01-01

    Ants can nest in a wide variety of substracts. This paper shows Syagrus romanzoffiana seed utilization by ants in an Atlantic secondary forest. We report 29 seeds occupied by small-bodied ants, with 27 of them showing at least two ant development stages. Although a large number of seeds were sampled, a low level of ant occupation was observed.

  20. Relative effects of disturbance on red imported fire ants and native ant species in a longleaf pine ecosystem

    DEFF Research Database (Denmark)

    Stuble, Katharine L.; Kirkman, L. Katherine; Carroll, C. Ronald

    2011-01-01

    and cases in which non-native species become established in intact (lacking extensive anthropogenic soil disturbance) communities and subsequently diminish the abundance and richness of native species is challenging on the basis of observation alone. The red imported fire ant (Solenopsis invicta......), an invasive species that occurs throughout much of the southeastern United States, is such an example. Rather than competitively displacing native species, fire ants may become established only in disturbed areas in which native species richness and abundance are already reduced. We used insecticide to reduce......, the abundance of native ants increased to levels comparable to those in control plots after 1 year. Our findings suggest that factors other than large reductions in ant abundance and species density (number of species per unit area) may affect the establishment of fire ants and that the response of native ants...

  1. La escritura como espada ante el machismo

    OpenAIRE

    Rottoli, Sofía

    2016-01-01

    Cuando se trata de expresar una postura que abarque una temática demasiado amplia o controversial, recurrir a la escritura puede ser una buena opción de abordaje. Sobre todo cuando son discusiones que llevan años de vigencia. Las luchas feministas ante la violencia de género no son una excepción. Sus discusiones siempre tuvieron presencia en diversos campos, uno de ellos es la ya mencionada escritura. Centro de Investigación en Lectura y Escritura (CILE)

  2. Ecology: 'Devil's gardens' bedevilled by ants.

    Science.gov (United States)

    Frederickson, Megan E; Greene, Michael J; Gordon, Deborah M

    2005-09-22

    'Devil's gardens' are large stands of trees in the Amazonian rainforest that consist almost entirely of a single species, Duroia hirsuta, and, according to local legend, are cultivated by an evil forest spirit. Here we show that the ant Myrmelachista schumanni, which nests in D. hirsuta stems, creates devil's gardens by poisoning all plants except its host plants with formic acid. By killing these other plants, M. schumanni provides its colonies with abundant nest sites--a long-lasting benefit as colonies can live for 800 years.

  3. Ante-natal ionising radiation and cancer

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This editorial comments on the latest reports of the Oxford Survey of Childhood Cancer (now based on Birmingham). With 14759 pairs, the latest survey is over 10-fold larger than the 1958 report and the calculation of fatal childhood cancer rate at one case in 990 ante-natal radiographic examinations is rather larger than the early estimates, in spite of the fetal radiation dose having been halved and the cure rate for childhood leukemia being much improved. Comments are made on the comparisons with bomb survivors, and on the much increased fatal cancer incidence after first trimester radiography. (UK)

  4. Ant Systems for a Dynamic TSP - Ants Caught in a Traffic Jam

    NARCIS (Netherlands)

    Eyckelhof, C.J.; Dorigo, M.; Caro Di, G.; Snoek, M.; Sampels, M.

    2002-01-01

    In this paper we present a new Ants System approach to a dynamic Travelling Salesman Problem. Here the travel times between the cities are subject to change. To handle this dynamism several ways of adapting the pheromone matrix both locally and globally are considered. We show that the strategy of

  5. Principals as Assessment Leaders in Rural Schools

    Science.gov (United States)

    Renihan, Patrick; Noonan, Brian

    2012-01-01

    This article reports a study of rural school principals' assessment leadership roles and the impact of rural context on their work. The study involved three focus groups of principals serving small rural schools of varied size and grade configuration in three systems. Principals viewed assessment as a matter of teacher accountability and as a…

  6. Principal Stability and the Rural Divide

    Science.gov (United States)

    Pendola, Andrew; Fuller, Edward J.

    2018-01-01

    This article examines the unique features of the rural school context and how these features are associated with the stability of principals in these schools. Given the small but growing literature on the characteristics of rural principals, this study presents an exploratory analysis of principal stability across schools located in different…

  7. New Principal Coaching as a Safety Net

    Science.gov (United States)

    Celoria, Davide; Roberson, Ingrid

    2015-01-01

    This study examines new principal coaching as an induction process and explores the emotional dimensions of educational leadership. Twelve principal coaches and new principals--six of each--participated in this qualitative study that employed emergent coding (Creswell, 2008; Denzin, 2005; Glaser & Strauss, 1998; Spradley, 1979). The major…

  8. 12 CFR 561.39 - Principal office.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Principal office. 561.39 Section 561.39 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY DEFINITIONS FOR REGULATIONS AFFECTING ALL SAVINGS ASSOCIATIONS § 561.39 Principal office. The term principal office means the home...

  9. The Principal as Academician: The Renewed Voice.

    Science.gov (United States)

    McAvoy, Brenda, Ed.

    This collection of essays was written by principals who participated in the 1986-87 Humanities Seminar sponsored by the Principals' Institute of Georgia State University. The focus was "The Evolution of Intellectual Leadership." The roles of the principal as philosopher, historian, ethnician, writer and team member are examined through…

  10. Principal-Counselor Collaboration and School Climate

    Science.gov (United States)

    Rock, Wendy D.; Remley, Theodore P.; Range, Lillian M.

    2017-01-01

    Examining whether principal-counselor collaboration and school climate were related, researchers sent 4,193 surveys to high school counselors in the United States and received 419 responses. As principal-counselor collaboration increased, there were increases in counselors viewing the principal as supportive, the teachers as regarding one another…

  11. Modelling Monthly Mental Sickness Cases Using Principal ...

    African Journals Online (AJOL)

    The methodology was principal component analysis (PCA) using data obtained from the hospital to estimate regression coefficients and parameters. It was found that the principal component regression model that was derived was good predictive tool. The principal component regression model obtained was okay and this ...

  12. Principals' Collaborative Roles as Leaders for Learning

    Science.gov (United States)

    Kitchen, Margaret; Gray, Susan; Jeurissen, Maree

    2016-01-01

    This article draws on data from three multicultural New Zealand primary schools to reconceptualize principals' roles as leaders for learning. In doing so, the writers build on Sinnema and Robinson's (2012) article on goal setting in principal evaluation. Sinnema and Robinson found that even principals hand-picked for their experience fell short on…

  13. Perceptions of Beginning Public School Principals.

    Science.gov (United States)

    Lyons, James E.

    1993-01-01

    Summarizes a study to determine principal's perceptions of their competency in primary responsibility areas and their greatest challenges and frustrations. Beginning principals are challenged by delegating responsibilities and becoming familiar with the principal's role, the local school, and school operations. Their major frustrations are role…

  14. Teacher Supervision Practices and Principals' Characteristics

    Science.gov (United States)

    April, Daniel; Bouchamma, Yamina

    2015-01-01

    A questionnaire was used to determine the individual and collective teacher supervision practices of school principals and vice-principals in Québec (n = 39) who participated in a research-action study on pedagogical supervision. These practices were then analyzed in terms of the principals' sociodemographic and socioprofessional characteristics…

  15. Leadership Coaching for Principals: A National Study

    Science.gov (United States)

    Wise, Donald; Cavazos, Blanca

    2017-01-01

    Surveys were sent to a large representative sample of public school principals in the United States asking if they had received leadership coaching. Comparison of responses to actual numbers of principals indicates that the sample represents the first national study of principal leadership coaching. Results indicate that approximately 50% of all…

  16. 41 CFR 105-68.995 - Principal.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Principal. 105-68.995 Section 105-68.995 Public Contracts and Property Management Federal Property Management Regulations System...-GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 105-68.995 Principal. Principal means— (a...

  17. A principal-agent Model of corruption

    NARCIS (Netherlands)

    Groenendijk, Nico

    1997-01-01

    One of the new avenues in the study of political corruption is that of neo-institutional economics, of which the principal-agent theory is a part. In this article a principal-agent model of corruption is presented, in which there are two principals (one of which is corrupting), and one agent (who is

  18. Nectar Theft and Floral Ant-Repellence: A Link between Nectar Volume and Ant-Repellent Traits?

    Science.gov (United States)

    Ballantyne, Gavin; Willmer, Pat

    2012-01-01

    As flower visitors, ants rarely benefit a plant. They are poor pollinators, and can also disrupt pollination by deterring other flower visitors, or by stealing nectar. Some plant species therefore possess floral ant-repelling traits. But why do particular species have such traits when others do not? In a dry forest in Costa Rica, of 49 plant species around a third were ant-repellent at very close proximity to a common generalist ant species, usually via repellent pollen. Repellence was positively correlated with the presence of large nectar volumes. Repellent traits affected ant species differently, some influencing the behaviour of just a few species and others producing more generalised ant-repellence. Our results suggest that ant-repellent floral traits may often not be pleiotropic, but instead could have been selected for as a defence against ant thieves in plant species that invest in large volumes of nectar. This conclusion highlights to the importance of research into the cost of nectar production in future studies into ant-flower interactions. PMID:22952793

  19. Partial incompatibility between ants and symbiotic fungi in two sympatric species of Acromyrmex leaf-cutting ants.

    Science.gov (United States)

    Bot, A N; Rehner, S A; Boomsma, J J

    2001-10-01

    We investigate the nature and duration of incompatibility between certain combinations of Acromyrmex leaf-cutting ants and symbiotic fungi, taken from sympatric colonies of the same or a related species. Ant-fungus incompatibility appeared to be largely independent of the ant species involved, but could be explained partly by genetic differences among the fungus cultivars. Following current theoretical considerations, we develop a hypothesis, originally proposed by S. A. Frank, that the observed incompatibilities are ultimately due to competitive interactions between genetically different fungal lineages, and we predict that the ants should have evolved mechanisms to prevent such competition between cultivars within a single garden. This requires that the ants are able to recognize unfamiliar fungi, and we show that this is indeed the case. Amplified fragment length polymorphism genotyping further shows that the two sympatric Acromyrmex species share each other's major lineages of cultivar, confirming that horizontal transfer does occasionally take place. We argue and provide some evidence that chemical substances produced by the fungus garden may mediate recognition of alien fungi by the ants. We show that incompatibility between ants and transplanted, genetically different cultivars is indeed due to active killing of the novel cultivar by the ants. This incompatibility disappears when ants are force-fed the novel cultivar for about a week, a result that is consistent with our hypothesis of recognition induced by the resident fungus and eventual replacement of incompatibility compounds during force-feeding.

  20. The importance of ants in cave ecology, with new records and behavioral observations of ants in Arizona caves

    Directory of Open Access Journals (Sweden)

    Robert B. Pape

    2016-09-01

    Full Text Available The importance of ants as elements in cave ecology has been mostly unrecognized. A global list of ant species recorded from caves, compiled from a review of existing literature, is presented. This paper also reviews what is currently known about ants occurring in Arizona (USA caves. The diversity and distribution represented in these records suggests ants are relatively common cave visitors (trogloxenes. A general utilization of caves by ants within both temperate and tropical latitudes may be inferred from this combined evidence. Observations of ant behavior in Arizona caves demonstrate a low level and sporadic, but persistent, use of these habitats and their contained resources by individual ant colonies. Documentation of Neivamyrmex sp. preying on cave-inhabiting arthropods is reported here for the first time. Observations of hypogeic army ants in caves suggests they may not penetrate to great vertical depth in search of prey, but can be persistent occupants in relatively shallow, horizontal sections of caves where they may prey on endemic cave animals. First cave records for ten ant species are reported from Arizona caves. These include two species of Neivamyrmex (N. nigrescens Cresson and Neivamyrmex sp.; Formicidae: Dorylinae, four myrmicines (Pheidole portalensis Wilson, Pheidole cf. porcula Wheeler, Solenopsis aurea Wheeler and Stenamma sp. Westwood, one dolichoderine (Forelius keiferi Wheeler and three formicines (Lasius arizonicus Wheeler, L. sitiens Wilson, and Camponotus sp. Mayr.

  1. ANT tuner retrofit for LEB cavity

    International Nuclear Information System (INIS)

    Walling, L.; Goren, Y.; Kwiatkowski, S.

    1994-03-01

    This report describes a ferrite tuner design for the LEB cavity that utilizes techniques for bonding ferrite to metallic cooling plates that is utilized in the high-power rf and microwave industry. A test tuner was designed to fit into the existing LEB-built magnet and onto the Grimm LEB Cavity. It will require a new vacuum window in order to attain maximal tuning range and high voltage capability and a new center conductor of longer length and a different vacuum window connection than the Grimm center conductor. However, the new center conductor will be essentially identical to the Grimm center conductor in its basic construction and in the way it connects to the stand for support. The tuner is mechanically very similar to high-power stacked circulators built by ANT of Germany and was designed according to ANT's established engineering and design criteria and SSC LEB tuning and power requirements. The tuner design incorporates thin tiles of ferrite glued using a high-radiation-resistance epoxy to copper-plated stainless steel cooling plates of thickness 6.5 mm with water cooling channels inside the plates. The cooling plates constitute 16 pie-shaped segments arranged in a disk. They are electrically isolated from each other to suppress eddy currents. Five of these disks are arranged in parallel with high-pressure rf contacts between the plates at the outer radius. The end walls are slotted copper-plated stainless steel of thickness 3 mm

  2. Loading pattern optimization using ant colony algorithm

    International Nuclear Information System (INIS)

    Hoareau, Fabrice

    2008-01-01

    Electricite de France (EDF) operates 58 nuclear power plants (NPP), of the Pressurized Water Reactor type. The loading pattern optimization of these NPP is currently done by EDF expert engineers. Within this framework, EDF R and D has developed automatic optimization tools that assist the experts. LOOP is an industrial tool, developed by EDF R and D and based on a simulated annealing algorithm. In order to improve the results of such automatic tools, new optimization methods have to be tested. Ant Colony Optimization (ACO) algorithms are recent methods that have given very good results on combinatorial optimization problems. In order to evaluate the performance of such methods on loading pattern optimization, direct comparisons between LOOP and a mock-up based on the Max-Min Ant System algorithm (a particular variant of ACO algorithms) were made on realistic test-cases. It is shown that the results obtained by the ACO mock-up are very similar to those of LOOP. Future research will consist in improving these encouraging results by using parallelization and by hybridizing the ACO algorithm with local search procedures. (author)

  3. Ant Foraging Behavior for Job Shop Problem

    Directory of Open Access Journals (Sweden)

    Mahad Diyana Abdul

    2016-01-01

    Full Text Available Ant Colony Optimization (ACO is a new algorithm approach, inspired by the foraging behavior of real ants. It has frequently been applied to many optimization problems and one such problem is in solving the job shop problem (JSP. The JSP is a finite set of jobs processed on a finite set of machine where once a job initiates processing on a given machine, it must complete processing and uninterrupted. In solving the Job Shop Scheduling problem, the process is measure by the amount of time required in completing a job known as a makespan and minimizing the makespan is the main objective of this study. In this paper, we developed an ACO algorithm to minimize the makespan. A real set of problems from a metal company in Johor bahru, producing 20 parts with jobs involving the process of clinching, tapping and power press respectively. The result from this study shows that the proposed ACO heuristics managed to produce a god result in a short time.

  4. The effect of diet and opponent size on aggressive interactions involving caribbean crazy ants (Nylanderia fulva.

    Directory of Open Access Journals (Sweden)

    Katherine C Horn

    Full Text Available Biotic interactions are often important in the establishment and spread of invasive species. In particular, competition between introduced and native species can strongly influence the distribution and spread of exotic species and in some cases competition among introduced species can be important. The Caribbean crazy ant, Nylanderia fulva, was recently introduced to the Gulf Coast of Texas, and appears to be spreading inland. It has been hypothesized that competition with the red imported fire ant, Solenopsis invicta, may be an important factor in the spread of crazy ants. We investigated the potential of interspecific competition among these two introduced ants by measuring interspecific aggression between Caribbean crazy ant workers and workers of Solenopsis invicta. Specifically, we examined the effect of body size and diet on individual-level aggressive interactions among crazy ant workers and fire ants. We found that differences in diet did not alter interactions between crazy ant workers from different nests, but carbohydrate level did play an important role in antagonistic interactions with fire ants: crazy ants on low sugar diets were more aggressive and less likely to be killed in aggressive encounters with fire ants. We found that large fire ants engaged in fewer fights with crazy ants than small fire ants, but fire ant size affected neither fire ant nor crazy ant mortality. Overall, crazy ants experienced higher mortality than fire ants after aggressive encounters. Our findings suggest that fire ant workers might outcompete crazy ant workers on an individual level, providing some biotic resistance to crazy ant range expansion. However, this resistance may be overcome by crazy ants that have a restricted sugar intake, which may occur when crazy ants are excluded from resources by fire ants.

  5. Principal component regression analysis with SPSS.

    Science.gov (United States)

    Liu, R X; Kuang, J; Gong, Q; Hou, X L

    2003-06-01

    The paper introduces all indices of multicollinearity diagnoses, the basic principle of principal component regression and determination of 'best' equation method. The paper uses an example to describe how to do principal component regression analysis with SPSS 10.0: including all calculating processes of the principal component regression and all operations of linear regression, factor analysis, descriptives, compute variable and bivariate correlations procedures in SPSS 10.0. The principal component regression analysis can be used to overcome disturbance of the multicollinearity. The simplified, speeded up and accurate statistical effect is reached through the principal component regression analysis with SPSS.

  6. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

    Science.gov (United States)

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  7. Frecuencia fenotípica y génica de los antígenos HLA en una muestra de la población cubana

    OpenAIRE

    Morera Barrios, Luz M; R, Catalino; García, Ustáriz; García García, María A.; Díaz Báez, Nelioska; Lam Díaz, Rosa M; Guerreiro Hernández, Ana M; Hernández Ramírez, Porfirio; Ballester Santovenia, José M

    2005-01-01

    Se realizó un estudio de la frecuencia fenotípica y génica de los antígenos del sistema principal de histocompatibilidad HLA en personas no relacionadas, supuestamente sanas, tomadas como muestra de la población cubana. Se analizó la distribución de 87 antígenos HLA clase I ( loci A, B y C) y 25 clase II ( loci DR y DQ). Se emplearon las técnicas de microlinfocitotoxicidad (serológica) descrita por Terasaki y modificada por el NIH para los antígenos de clase I, y las técnicas de biología mole...

  8. Current and potential ant impacts in the Pacific region

    Science.gov (United States)

    Loope, Lloyd L.; Krushelnycky, Paul D.

    2007-01-01

    Worldwide, ants are a powerful ecological force, and they appear to be dominant components of animal communities of many tropical and temperate ecosystems in terms of biomass and numbers of individuals (Bluthgen et al. 2000). For example, ants comprise up to 94% of arthropod individuals in fogging samples taken from diverse lowland tropical rainforest canopies, and 86% of the biomass (Davidson et al. 2003). The majority of these ant species and individuals obtain carbohydrates either from extrafloral nectaries or from sap-feeding Hemiptera that pass carbohydrate-rich “honeydew” to attending ants while concentrating nitrogen (N) from N-poor plant sap (Davidson et al. 2003). Honeydew and nectar represent key resources for arboreal ant species, although most ant species are at least partly carnivorous or scavengers (Bluthgen et al. 2004). In contrast to most of the terrestrial world, the biotas of many Pacific islands evolved without ants. Whereas endemic ant species are found in New Zealand (ca. 10 spp.), Tonga (ca. 10 spp.), and Samoa (ca. 12 spp.), other islands of Polynesia and parts of Micronesia likely lack native ants (Wilson and Taylor 1967, Wetterer 2002, Wetterer and Vargo 2003). About 20 Indo-Australian and western Pacific ant species range to the east and north of Samoa, but it is unclear how many of these were transported there by humans at some time (Wilson and Taylor 1967). Most of the remainder of the ant species currently found on Pacific islands are widespread species that fall in the category of “tramp species,” dispersed by recent human commerce and generally closely tied to human activity and urban areas (Wilson and Taylor 1967, McGlynn 1999). In Pacific island situations, some of these tramp ant species are able to thrive beyond areas of human activity. Relatively few ant species have been successful invaders of native communities on continents, and these include most of the species that pose the greatest problems for Pacific islands

  9. Teaching Principal Components Using Correlations.

    Science.gov (United States)

    Westfall, Peter H; Arias, Andrea L; Fulton, Lawrence V

    2017-01-01

    Introducing principal components (PCs) to students is difficult. First, the matrix algebra and mathematical maximization lemmas are daunting, especially for students in the social and behavioral sciences. Second, the standard motivation involving variance maximization subject to unit length constraint does not directly connect to the "variance explained" interpretation. Third, the unit length and uncorrelatedness constraints of the standard motivation do not allow re-scaling or oblique rotations, which are common in practice. Instead, we propose to motivate the subject in terms of optimizing (weighted) average proportions of variance explained in the original variables; this approach may be more intuitive, and hence easier to understand because it links directly to the familiar "R-squared" statistic. It also removes the need for unit length and uncorrelatedness constraints, provides a direct interpretation of "variance explained," and provides a direct answer to the question of whether to use covariance-based or correlation-based PCs. Furthermore, the presentation can be made without matrix algebra or optimization proofs. Modern tools from data science, including heat maps and text mining, provide further help in the interpretation and application of PCs; examples are given. Together, these techniques may be used to revise currently used methods for teaching and learning PCs in the behavioral sciences.

  10. Ultrastructure of antennal sensillae of the samsum ant ...

    African Journals Online (AJOL)

    Black ant (Samsum), Pachycodyla sennarrensis, stings and injects venom and inflicts allergy (a rare clinical problem) due to its local and systemic reaction, which is considered as a health hazard amongst Saudi society. Thus, black ant is a source of serious concern for the government and experts as well.

  11. Development of a Bait System for the Pharaoh's Ant, Monomorium ...

    African Journals Online (AJOL)

    The infestation of the Pharaoh's ant, Monomorium pharaonis L. is widespread and, sometimes, very serious in homes, hospitals, restaurants, factories, etc. People are helpless because effective baited traps are not available locally, and little has been done locally to develop effective control strategies for these ants.

  12. A preliminary checklist of the ants (Hymenoptera: Formicidae) of ...

    African Journals Online (AJOL)

    A preliminary species checklist of the ants (Hymenoptera: Formicidae) of. Kakamega Forest, Western Kenya, is presented. The species list is based on specimens sampled from 1999 until 2009, which are deposited in the ant collection of the Zoological Research Museum Koenig, Bonn, Germany, and the Natural History ...

  13. Ant species richness of fynbos and forest ecosystems in the ...

    African Journals Online (AJOL)

    The ant fauna in fynbos and forest habitats in the southern Cape are compared. There is no significant difference in ant species richness between the two undisturbed habitat types, and the only two species common to both are Acantholepis capensis and Camponotus maculatus. The degree of Hakea sericea infestation in ...

  14. Volatile chemicals in glands of the carpenter ant, Camponotus ...

    African Journals Online (AJOL)

    Volatile chemicals in glands of the carpenter ant, Camponotus arminius. J.M. Brand, L.V. Mabinya, E.D. Morgan. Abstract. Camponotus arminius is a large black carpenter ant that occurs in tropical and sub-tropical Africa and has extensive foraging trails both in trees and on the ground. Analysis of excised mandibular glands ...

  15. Novel Phialophora species from leaf-cutting ants (tribe Attini)

    NARCIS (Netherlands)

    Attili-Angelis, D.; Duarte, A.P.M.; Pagnocca, F.C.; Nagamoto, N.S.; de Vries, M.; Stielow, J.B.; de Hoog, G.S.

    2014-01-01

    Ants in the tribe Attini (Hymenoptera, Formicidae) maintain a 50 million-year-old lifestyle of co-evolution with symbiotic basidiomycetous fungi which they cultivate as essential source of nutrition. However, other microorganisms have been reported from ant habitats indicating a higher diversity of

  16. Why do house-hunting ants recruit in both directions?

    NARCIS (Netherlands)

    Planqué, R.; Dechaume-Moncharmont, F.-X.; Franks, N.R.; Kovacs, T.; Marshall, J.A.R.

    2007-01-01

    To perform tasks, organisms often use multiple procedures. Explaining the breadth of such behavioural repertoires is not always straightforward. During house hunting, colonies of Temnothorax albipennis ants use a range of behaviours to organise their emigrations. In particular, the ants use tandem

  17. Tracing the rise of ants - out of the ground.

    Directory of Open Access Journals (Sweden)

    Andrea Lucky

    Full Text Available The evolution of ants (Hymenoptera: Formicidae is increasingly well-understood due to recent phylogenetic analyses, along with estimates of divergence times and diversification rates. Yet, leading hypotheses regarding the ancestral habitat of ants conflict with new findings that early ant lineages are cryptic and subterranean. Where the ants evolved, in respect to habitat, and how habitat shifts took place over time have not been formally tested. Here, we reconstruct the habitat transitions of crown-group ants through time, focusing on where they nest and forage (in the canopy, litter, or soil. Based on ancestral character reconstructions, we show that in contrast to the current consensus based on verbal arguments that ants evolved in tropical leaf litter, the soil is supported as the ancestral stratum of all ants. We also find subsequent movements up into the litter and, in some cases, into the canopy. Given the global importance of ants, because of their diversity, ecological influence and status as the most successful eusocial lineage on Earth, understanding the early evolution of this lineage provides insight into the factors that made this group so successful today.

  18. In vitro studies of ante-mortem proliferation kinetics

    International Nuclear Information System (INIS)

    McBride, W.H.; Withers, H.R.

    1986-01-01

    Using K562 human erythroblastoid cells, it was concluded that dose fractionation has no discrepant effect on the ante-mortem proliferation kinetics of doomed cells as opposed to clonogenic cell survival and that effects on ante-mortem proliferation kinetics cannot be solely responsible for the differences in fractionation response between early and late responding tissues. (UK)

  19. Reciprocal genomic evolution in the ant-fungus agricultural symbiosis

    DEFF Research Database (Denmark)

    Nygaard, Sanne; Hu, Haofu; Li, Cai

    2016-01-01

    The attine ant-fungus agricultural symbiosis evolved over tens of millions of years, producing complex societies with industrial-scale farming analogous to that of humans. Here we document reciprocal shifts in the genomes and transcriptomes of seven fungus-farming ant species and their fungal...

  20. Life-Histories of Sub-Arctic Ants

    OpenAIRE

    Heinze, Jürgen

    1993-01-01

    Ant species belonging to seven genera occur in habitats near the tree line in the Northern Hemisphere. An analysis of colony founding strategies suggests that in addition to physiological cold resistance, behavioral and sociometric adaptations might be important for survival and propagation of ants in subarctic biomes.

  1. Studies of laboulbeniales (Fungi, Ascomycota) on myrmica ants (II)

    NARCIS (Netherlands)

    Haelewaters, Danny; Boer, Peter; Gort, Gerrit; Noordijk, Jinze

    2015-01-01

    One group of important insect parasites are the Laboulbeniales (Ascomycota), microscopic fungi that live attached to the exterior of their hosts, mainly beetles, but also mites, millipedes, earwigs, and ants. Rickia wasmannii is a common fungus in Europe and is limited to the ant genus Myrmica

  2. ADAPTIVE ANT COLONY OPTIMIZATION BASED GRADIENT FOR EDGE DETECTION

    Directory of Open Access Journals (Sweden)

    Febri Liantoni

    2014-08-01

    Full Text Available Ant Colony Optimization (ACO is a nature-inspired optimization algorithm which is motivated by ants foraging behavior. Due to its favorable advantages, ACO has been widely used to solve several NP-hard problems, including edge detection. Since ACO initially distributes ants at random, it may cause imbalance ant distribution which later affects path discovery process. In this paper an adaptive ACO is proposed to optimize edge detection by adaptively distributing ant according to gradient analysis. Ants are adaptively distributed according to gradient ratio of each image regions. Region which has bigger gradient ratio, will have bigger number of ant distribution. Experiments are conducted using images from various datasets. Precision and recall are used to quantitatively evaluate performance of the proposed algorithm. Precision and recall of adaptive ACO reaches 76.98 % and 96.8 %. Whereas highest precision and recall for standard ACO are 69.74 % and 74.85 %. Experimental results show that the adaptive ACO outperforms standard ACO which randomly distributes ants.

  3. Patterns of male parentage in the fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Boomsma, JJ

    2003-01-01

    Ant queens from eight species, covering three genera of lower and two genera of higher attine ants, have exclusively or predominantly single mating. The ensuing full-sib colonies thus have a strong potential reproductive conflict between the queen and the workers over male production...

  4. Odorous house ants (Tapinoma sessile as back-seat drivers of localized ant decline in urban habitats.

    Directory of Open Access Journals (Sweden)

    Adam Salyer

    Full Text Available Invasive species and habitat disturbance threaten biodiversity worldwide by modifying ecosystem performance and displacing native organisms. Similar homogenization impacts manifest locally when urbanization forces native species to relocate or reinvade perpetually altered habitat. This study investigated correlations between ant richness and abundance in response to urbanization and the nearby presence of invasive ant species, odorous house ants (Tapinoma sessile, within its native region. Surveying localized ant composition within natural, semi-natural, and urban habitat supported efforts to determine whether T. sessile appear to be primary (drivers threats as instigators or secondary (passengers threats as inheritors of indigenous ant decline. Sampling 180 sites, evenly split between all habitats with and without T. sessile present, yielded 45 total species. Although urbanization and T. sessile presence factors were significantly linked to ant decline, their interaction correlated to the greatest reduction of total ant richness (74% and abundance (81%. Total richness appeared to decrease from 27 species to 18 when natural habitat is urbanized and from 18 species to 7 with T. sessile present in urban plots. Odorous house ant presence minimally influenced ant communities within natural and semi-natural habitat, highlighting the importance of habitat alteration and T. sessile presence interactions. Results suggest urbanization releases T. sessile from unknown constraints by decreasing ant richness and competition. Within urban environment, T. sessile are pre-adapted to quickly exploit new resources and grow to supercolony strength wherein T. sessile drive adjacent biodiversity loss. Odorous house ants act as passengers and drivers of ecological change throughout different phases of urban 'invasion'. This progression through surviving habitat alteration, exploiting new resources, thriving, and further reducing interspecific competition supports a

  5. Conducta conservadora ante el traumatismo esplénico

    Directory of Open Access Journals (Sweden)

    María Eugenia Ferro Moreira

    2011-03-01

    Full Text Available INTRODUCCIÓN. El bazo es el órgano que más frecuentemente se lesiona en los traumatismos abdominales. Fueron objetivos de este trabajo describir la conducta conservadora ante el traumatismo esplénico y determinar su frecuencia en el Hospital Pediátrico «Juan Manuel Márquez», centro provincial de atención al niño politraumatizado, donde se preconiza esta conducta por los beneficios que ofrece la preservación del bazo a la función inmunológica. MÉTODOS. Se realizó un estudio prospectivo con 36 pacientes con traumatismo esplénico que fueron tratados de forma conservadora teniendo como criterio principal la estabilidad hemodinámica del paciente. Se analizó edad, sexo, causa de lesión esplénica, lesiones asociadas, tratamiento conservador realizado, complicaciones y estadía hospitalaria. RESULTADOS. El traumatismo esplénico estuvo presente en el 66,6 % de los traumatismos abdominales. Las causas más frecuentes fueron los accidentes de tránsito (50 %, seguidos de las caídas desde alturas (33 %. En el 89 % de los pacientes se siguió una conducta conservadora: en el 88 % de los casos se aplicó tratamiento médico conservador y en el 11 %, métodos quirúrgicos de conservación esplénica. CONCLUSIONES. Todas las lesiones ocurrieron por traumatismos contusos. Las técnicas quirúrgicas utilizadas fueron dos esplenorrafias y una esplenectomía parcial. No hubo fallecidos y las complicaciones fueron mínimas, por lo que consideramos que la conducta conservadora del traumatismo esplénico es una modalidad de tratamiento segura en la infancia.

  6. Weaver Ants to Control Fruit Fly Damage to Tanzanian Mangoes

    DEFF Research Database (Denmark)

    Kirkegaard, Nina

    in Australia and West Africa. In this study, small scale farmers did not think weaver ants protected their mangoes from fruit flies. Observational studies confirmed the farmers’ views. No volatile compounds, likely to be responsible for the weaver ants’ deterrent effect, were identified. This study focused...... mangoes varied a lot with zero infestation in some fruits and more than 100 pupae emerging from other fruits, indicating that other factors than the presence of weaver ants affect the fruit flies’ decision on where to oviposit. It was not uncommon for farmers to place newly harvested mangoes below mango...... not shown to be effectively deterring fruit flies, there is no great motivation for farmers to adopt weaver ants. Assuming the weaver ants could be managed in a way that made weaver ants deter fruit flies effectively there are still some economic aspects which should be studied further. It is necessary...

  7. Behind every great ant, there is a great gut

    DEFF Research Database (Denmark)

    Poulsen, Michael; Sapountzis, Panagiotis

    2012-01-01

    on the potential contribution of the ants’ gut symbionts. This issue of Molecular Ecology contains a study by Anderson et al. (2012), who take a comparative approach to explore the link between trophic levels and ant microbiomes, specifically, to address three main questions: (i) Do closely related herbivorous...... conserved gut microbiomes, suggesting symbiont functions that directly relate to dietary preference of the ant host. These findings suggest an ecological role of gut symbionts in ants, for example, in metabolism and/or protection, and the comparative approach taken supports a model of co-evolution between...... ant species and specific core symbiont microbiomes. This study, thereby, highlights the omnipresence and importance of gut symbioses—also in the Hymenoptera—and suggests that these hitherto overlooked microbes likely have contributed to the ecological success of the ants....

  8. Endophytic fungi reduce leaf-cutting ant damage to seedlings

    Science.gov (United States)

    Bittleston, L. S.; Brockmann, F.; Wcislo, W.; Van Bael, S. A.

    2011-01-01

    Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (Ehigh) or low (Elow) densities of endophytes. The Ehigh seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the Elow treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from Elow relative to Ehigh seedlings and had a tendency to recruit more ants to Elow plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities. PMID:20610420

  9. Egg-laying butterflies distinguish predaceous ants by sight.

    Science.gov (United States)

    Sendoya, Sebastián F; Freitas, André V L; Oliveira, Paulo S

    2009-07-01

    Information about predation risks is critical for herbivorous insects, and natural selection favors their ability to detect predators before oviposition and to select enemy-free foliage when offspring mortality risk is high. Food plants are selected by ovipositing butterflies, and offspring survival frequently varies among plants because of variation in the presence of predators. Eunica bechina butterflies oviposit on Caryocar brasiliense, an ant-defended plant. Experiments with dried Camponotus and Cephalotes ants pinned to leaves revealed that butterflies use ant size and form as visual cues to avoid ovipositing on plant parts occupied by ants more likely to kill larval offspring. Presence of sap-sucking bugs did not affect butterfly oviposition. This is the first demonstration that visual recognition of predators can mediate egg-laying decisions by an insect herbivore and that an insect will discriminate among different species of potential predators. This unusual behavioral capability permits specialization on a risky, ant-defended food plant.

  10. ANT International chemistry update and best practices

    International Nuclear Information System (INIS)

    Nordmann, F.; Odar, S.; Venz, H.; Kysela, J.; Ruehle, W.; Riess, R.

    2010-01-01

    There is an increasing number of Nuclear Power Plants (NPP) in various countries. Their chemistry practices are different due to the variety of designs and experiences while in the past the view was more monolithic. This is allowing a very rich experience that is extremely difficult to fully be aware of. ANT International is now collecting and evaluating these data as well as related R and D Information. This allows interested parties to have an easier access to the various sources of information. The chemistry experts associated to ANT International have been gathering a comprehensive detailed view of: The numerous laboratory data gained all over the world during the past decades; The extensive plant operating experiences with various types of chemistry strategies, crosschecked for various types of reactors designs and materials; An experienced international knowledge able to give the comprehensive overview that young engineers now in charge of many other activities are unable to fully cover. This paper gives the core conclusions of the detailed ANT International reports and results that have recently been gathered in the area of chemistry. It particularly covers: The primary water chemistry and its relation with radionuclides, dose rates and fuel behaviour; The secondary water chemistry focusing on its rationale selection depending on materials, design and other constraints; The start up and shutdown chemistry with it large variety of practices hardly understandable even for some experts; and, The maintenance remedies such as decontamination, steam generator cleaning and its alternate options. Various types of Reactor designs (PWR, VVER, BWR, CANDU®) are considered. The different materials, for example the impact of steam generator tubing and its evolution on the secondary water chemistry rationale or on the radioactivity built-up in the primary coolant, are described. The ways to improve the plant operation with a long term reliability as well as the most

  11. The regulation of ant colony foraging activity without spatial information.

    Directory of Open Access Journals (Sweden)

    Balaji Prabhakar

    Full Text Available Many dynamical networks, such as the ones that produce the collective behavior of social insects, operate without any central control, instead arising from local interactions among individuals. A well-studied example is the formation of recruitment trails in ant colonies, but many ant species do not use pheromone trails. We present a model of the regulation of foraging by harvester ant (Pogonomyrmex barbatus colonies. This species forages for scattered seeds that one ant can retrieve on its own, so there is no need for spatial information such as pheromone trails that lead ants to specific locations. Previous work shows that colony foraging activity, the rate at which ants go out to search individually for seeds, is regulated in response to current food availability throughout the colony's foraging area. Ants use the rate of brief antennal contacts inside the nest between foragers returning with food and outgoing foragers available to leave the nest on the next foraging trip. Here we present a feedback-based algorithm that captures the main features of data from field experiments in which the rate of returning foragers was manipulated. The algorithm draws on our finding that the distribution of intervals between successive ants returning to the nest is a Poisson process. We fitted the parameter that estimates the effect of each returning forager on the rate at which outgoing foragers leave the nest. We found that correlations between observed rates of returning foragers and simulated rates of outgoing foragers, using our model, were similar to those in the data. Our simple stochastic model shows how the regulation of ant colony foraging can operate without spatial information, describing a process at the level of individual ants that predicts the overall foraging activity of the colony.

  12. Immune defense in leaf-cutting ants

    DEFF Research Database (Denmark)

    Armitage, Sophie A O; Broch, Jens F; Marín, Hermogenes Fernández

    2011-01-01

    To ameliorate the impact of disease, social insects combine individual innate immune defenses with collective social defenses. This implies that there are different levels of selection acting on investment in immunity, each with their own trade-offs. We present the results of a cross......-fostering experiment designed to address the influences of genotype and social rearing environment upon individual and social immune defenses. We used a multiply mating leaf-cutting ant, enabling us to test for patriline effects within a colony, as well as cross-colony matriline effects. The worker's father influenced...... both individual innate immunity (constitutive antibacterial activity) and the size of the metapleural gland, which secretes antimicrobial compounds and functions in individual and social defense, indicating multiple mating could have important consequences for both defense types. However, the primarily...

  13. Ex-ante Evaluation von Investitionsalternativen

    Directory of Open Access Journals (Sweden)

    Matthias Müller

    2017-12-01

    Full Text Available Der Beitrag zeigt, wie mit Hilfe der Methode der agentenbasierten Modellierung und Simulation (ABMS ein Beitrag zur ex-ante Policy-Beratung geleistet werden kann. Anhand eines exemplarischen Anwendungsfalls, der VISIBLE Simulationsumgebung („Virtual Simulation Lab for the Analysis of Investments in Learning and Education“, diskutieren wir die Konsequenzen unterschiedlicher Kooperationsförderinstrumente für Wissensdiffusionsprozesse in Netzwerken am Beispiel der Region Heilbronn-Franken. Die Simulationsergebnisse zeigen, dass die strukturelle Konfiguration eines regionalen Innovationssystems eine zentrale Bedeutung für die Gestaltung von Kooperationsfördermaßnahmen hat und dass Interventionen, die darauf abzielen, Wissenstransfer zwischen den Akteuren anzuregen, genau die entgegengesetzten Wirkungen entfalten können.

  14. Swarm controlled emergence for ant clustering

    DEFF Research Database (Denmark)

    Scheidler, Alexander; Merkle, Daniel; Middendorf, Martin

    2013-01-01

    .g. moving robots, and clustering algorithms. Design/methodology/approach: Different types of control agents for that ant clustering model are designed by introducing slight changes to the behavioural rules of the normal agents. The clustering behaviour of the resulting swarms is investigated by extensive...... for future research to investigate the application of the method in other swarm systems. Swarm controlled emergence might be applied to control emergent effects in computing systems that consist of many autonomous components which make decentralized decisions based on local information. Practical...... simulation studies. Findings: It is shown that complex behavior can emerge in systems with two types of agents (normal agents and control agents). For a particular behavior of the control agents, an interesting swarm size dependent effect was found. The behaviour prevents clustering when the number...

  15. Discrimination Behavior in the Supercolonial Pharaoh Ant

    DEFF Research Database (Denmark)

    Pontieri, Luigi

    The majority of eusocial insect species live in small, kin structured colonies that are mutually aggressive and rarely interact. By contrast, a restricted group of ant species show a peculiar social organization called unicoloniality, where colonies can grow to vast networks of geographically...... and genetic distance between colony pairs, further confirming the important role of endogenous cues in the nestmate recognition of this species. The third chapter presents a methodological study on the best procedures for identifying chemical compounds used for nestmate recognition in social insects. We first...... evaluated the power of different combinations of data transformation and chemical distance calculation in differentiating between true nestmate recognition (NMR) cues and other compounds. We found that particular combinations of statistical procedures are more effective in differentiating NMR cues from...

  16. Reduction of symplectic principal R-bundles

    International Nuclear Information System (INIS)

    Lacirasella, Ignazio; Marrero, Juan Carlos; Padrón, Edith

    2012-01-01

    We describe a reduction process for symplectic principal R-bundles in the presence of a momentum map. These types of structures play an important role in the geometric formulation of non-autonomous Hamiltonian systems. We apply this procedure to the standard symplectic principal R-bundle associated with a fibration π:M→R. Moreover, we show a reduction process for non-autonomous Hamiltonian systems on symplectic principal R-bundles. We apply these reduction processes to several examples. (paper)

  17. Entomopathogens Isolated from Invasive Ants and Tests of Their Pathogenicity

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Miori de Zarzuela

    2012-01-01

    Full Text Available Some ant species cause severe ecological and health impact in urban areas. Many attempts have been tested to control such species, although they do not always succeed. Biological control is an alternative to chemical control and has gained great prominence in research, and fungi and nematodes are among the successful organisms controlling insects. This study aimed to clarify some questions regarding the biological control of ants. Invasive ant species in Brazil had their nests evaluated for the presence of entomopathogens. Isolated entomopathogens were later applied in colonies of Monomorium floricola under laboratory conditions to evaluate their effectiveness and the behavior of the ant colonies after treatment. The entomopathogenic nematodes Heterorhabditis sp. and Steinernema sp. and the fungi Beauveria bassiana, Metarhizium anisopliae, and Paecilomyces sp. were isolated from the invasive ant nests. M. floricola colonies treated with Steinernema sp. and Heterorhabditis sp. showed a higher mortality of workers than control. The fungus Beauveria bassiana caused higher mortality of M. floricola workers. However, no colony reduction or elimination was observed in any treatment. The defensive behaviors of ants, such as grooming behavior and colony budding, must be considered when using fungi and nematodes for biological control of ants.

  18. The diversity of microorganisms associated with Acromyrmex leafcutter ants

    Directory of Open Access Journals (Sweden)

    Boomsma Jacobus J

    2002-05-01

    Full Text Available Abstract Background Molecular biological techniques are dramatically changing our view of microbial diversity in almost any environment that has so far been investigated. This study presents a systematic survey of the microbial diversity associated with a population of Acromyrmex leafcutter ants. In contrast to previous studies on social insects, which targeted specific groups of symbionts occurring in the gut (termites, Tetraponera ants or in specialised cells (Camponotus ants the objective of our present study was to do a total screening of all possible micro-organisms that can be found inside the bodies of these leafcutter ants. Results We amplified, cloned and sequenced SSU rRNA encoding gene fragments from 9 microbial groups known to have insect-associated representatives, and show that: (1 representatives of 5 out of 9 tested groups are present, (2 mostly several strains per group are present, adding up to a total of 33 different taxa. We present the microbial taxa associated with Acromymex ants in a phylogenetic context (using sequences from GenBank to assess and illustrate to which known microorganisms they are closely related. The observed microbial diversity is discussed in the light of present knowledge on the evolutionary history of Acromyrmex leafcutter ants and their known mutualistic and parasitic symbionts. Conclusions The major merits of the screening approach documented here is its high sensitivity and specificity, which allowed us to identify several microorganisms that are promising candidates for further study of their interactions with Acromyrmex leafcutter ants or their gardens.

  19. USING ANT COMMUNITIES FOR RAPID ASSESSMENT OF TERRESTRIAL ECOSYSTEM HEALTH

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L; Doug Martin, D; Michael Paller, M; Eric Nelson, E

    2007-01-12

    Ecosystem health with its near infinite number of variables is difficult to measure, and there are many opinions as to which variables are most important, most easily measured, and most robust, Bioassessment avoids the controversy of choosing which physical and chemical parameters to measure because it uses responses of a community of organisms that integrate all aspects of the system in question. A variety of bioassessment methods have been successfully applied to aquatic ecosystems using fish and macroinvertebrate communities. Terrestrial biotic index methods are less developed than those for aquatic systems and we are seeking to address this problem here. This study had as its objective to examine the baseline differences in ant communities at different seral stages from clear cut back to mature pine plantation as a precursor to developing a bioassessment protocol. Comparative sampling was conducted at four seral stages; clearcut, 5 year, 15 year and mature pine plantation stands. Soil and vegetation data were collected at each site. All ants collected were preserved in 70% ethyl alcohol and identified to genus. Analysis of the ant data indicates that ants respond strongly to the habitat changes that accompany ecological succession in managed pine forests and that individual genera as well as ant community structure can be used as an indicator of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in the mature seral stages was likely related to conditions on the forest floor which favored litter dwelling and cool climate specialists.

  20. Interactions Increase Forager Availability and Activity in Harvester Ants.

    Directory of Open Access Journals (Sweden)

    Evlyn Pless

    Full Text Available Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

  1. Competitive assembly of South Pacific invasive ant communities

    Directory of Open Access Journals (Sweden)

    Sarty Megan

    2009-01-01

    Full Text Available Abstract Background The relative importance of chance and determinism in structuring ecological communities has been debated for nearly a century. Evidence for determinism or assembly rules is often evaluated with null models that randomize the occurrence of species in particular locales. However, analyses of the presence or absence of species ignores the potential influence of species abundances, which have long been considered of major importance on community structure. Here, we test for community assembly rules in ant communities on small islands of the Tokelau archipelago using both presence-absence and abundance data. We conducted three sets of analyses on two spatial scales using three years of sampling data from 39 plots on 11 islands. Results First, traditional null model tests showed support for negative species co-occurrence patterns among plots within islands, but not among islands. A plausible explanation for this result is that analyses at larger spatial scales merge heterogeneous habitats that have considerable effects on species occurrences. Second, analyses of ant abundances showed that samples with high ant abundances had fewer species than expected by chance, both within and among islands. One ant species, the invasive yellow crazy ant Anoplolepis gracilipes, appeared to have a particularly strong effect on community structure correlated with its abundance. Third, abundances of most ant species were inversely correlated with the abundances of all other ants at both spatial scales. This result is consistent with competition theory, which predicts species distributions are affected by diffuse competition with suites of co-occurring species. Conclusion Our results support a pluralistic explanation for ant species abundances and assembly. Both stochastic and deterministic processes interact to determine ant community assembly, though abundance patterns clearly drive the deterministic patterns in this community. These deterministic

  2. Evolution of Fungal enzymes in the attine ant symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    The attine ant symbiosis is characterized by ancient but varying degrees of diffuse co-evolution between the ants and their fungal cultivars. Domesticated fungi became dependent on vertical transmission by queens and the ant colonies came to rely on their symbiotic fungus for food and thus...... as garden substrate, whereas the more basal genera use leaf litter, insect feces and insect carcasses. We hypothesized that enzyme activity of fungal symbionts has co-evolved with substrate use and we measured enzyme activities of fungus gardens in the field to test this, focusing particularly on plant...... essential for the symbiosis in general, but have contributed specifically to the evolution of the symbiosis....

  3. Comparative studies of the secretome of fungus-growing ants

    DEFF Research Database (Denmark)

    Linde, Tore; Grell, Morten Nedergaard; Schiøtt, Morten

    2009-01-01

    Leafcutter ants of the species Acromyrmex echinatior live in symbiosis with the fungus Leucoagaricus gongylophorus. The ants harvest fragments of leaves and carry them to the nest where they place the material on the fungal colony. The fungus secretes a wide array of proteins to degrade the leaves...... into nutrients that the ants can feed on. The focus of this study is to discover, characterize and compare the secreted proteins. In order to do so cDNA libraries are constructed from mRNA extracted from the fungus material. The most efficient technology to screen cDNA libraries selectively for secreted...

  4. Warehouse stocking optimization based on dynamic ant colony genetic algorithm

    Science.gov (United States)

    Xiao, Xiaoxu

    2018-04-01

    In view of the various orders of FAW (First Automotive Works) International Logistics Co., Ltd., the SLP method is used to optimize the layout of the warehousing units in the enterprise, thus the warehouse logistics is optimized and the external processing speed of the order is improved. In addition, the relevant intelligent algorithms for optimizing the stocking route problem are analyzed. The ant colony algorithm and genetic algorithm which have good applicability are emphatically studied. The parameters of ant colony algorithm are optimized by genetic algorithm, which improves the performance of ant colony algorithm. A typical path optimization problem model is taken as an example to prove the effectiveness of parameter optimization.

  5. Ant colony algorithm for clustering in portfolio optimization

    Science.gov (United States)

    Subekti, R.; Sari, E. R.; Kusumawati, R.

    2018-03-01

    This research aims to describe portfolio optimization using clustering methods with ant colony approach. Two stock portfolios of LQ45 Indonesia is proposed based on the cluster results obtained from ant colony optimization (ACO). The first portfolio consists of assets with ant colony displacement opportunities beyond the defined probability limits of the researcher, where the weight of each asset is determined by mean-variance method. The second portfolio consists of two assets with the assumption that each asset is a cluster formed from ACO. The first portfolio has a better performance compared to the second portfolio seen from the Sharpe index.

  6. Automating ActionScript Projects with Eclipse and Ant

    CERN Document Server

    Koning, Sidney

    2011-01-01

    Automating repetitive programming tasks is easier than many Flash/AS3 developers think. With the Ant build tool, the Eclipse IDE, and this concise guide, you can set up your own "ultimate development machine" to code, compile, debug, and deploy projects faster. You'll also get started with versioning systems, such as Subversion and Git. Create a consistent workflow for multiple machines, or even complete departments, with the help of extensive Ant code samples. If you want to work smarter and take your skills to a new level, this book will get you on the road to automation-with Ant. Set up y

  7. The invasion biology and sociogenetics of pharaoh ants

    DEFF Research Database (Denmark)

    Schmidt, Anna Mosegaard

    Social insect colonies perform a number of tasks affecting the environments they live in. Some unintentionally introduced species have attracted the attention of scientists and general public alike when causing a number of changes to the composition and functioning of ecosystems. Such ?invaders...... laboratory lineages, thus building the foundation for future research on the species. In addition, I have started a selection experiment (still ongoing in collaboration with Dr. T. Linksvayer) using pharaoh ants, which is the first time artificial selection is attempted in an ant species. Pharaoh ants have...

  8. New pulser for principal PO power

    International Nuclear Information System (INIS)

    Coudert, G.

    1984-01-01

    The pulser of the principal power of the PS is the unit that makes it possible to generate the reference function of the voltage of the principal magnet. This function depends on time and on the magnetic field of the magnet. It also generates various synchronization and reference pulses

  9. Principals: Human Capital Managers at Every School

    Science.gov (United States)

    Kimball, Steven M.

    2011-01-01

    Being a principal is more than just being an instructional leader. Principals also must manage their schools' teaching talent in a strategic way so that it is linked to school instructional improvement strategies, to the competencies needed to enact the strategies, and to success in boosting student learning. Teacher acquisition and performance…

  10. Constructing principals' professional identities through life stories ...

    African Journals Online (AJOL)

    The Life History approach was used to collect data from six ... experience as the most significant leadership factors that influence principals' ... ranging from their entry into the teaching profession to their appointment as ..... teachers. I think I learnt from my principal to be strict but accommodating ..... Teachers College Press.

  11. Integrating Technology: The Principals' Role and Effect

    Science.gov (United States)

    Machado, Lucas J.; Chung, Chia-Jung

    2015-01-01

    There are many factors that influence technology integration in the classroom such as teacher willingness, availability of hardware, and professional development of staff. Taking into account these elements, this paper describes research on technology integration with a focus on principals' attitudes. The role of the principal in classroom…

  12. Building Leadership Capacity to Support Principal Succession

    Science.gov (United States)

    Escalante, Karen Elizabeth

    2016-01-01

    This study applies transformational leadership theory practices, specifically inspiring a shared vision, modeling the way and enabling others to act to examine the purposeful ways in which principals work to build the next generation of teacher leaders in response to the dearth of K-12 principals. The purpose of this study was to discover how one…

  13. Deformation quantization of principal fibre bundles

    International Nuclear Information System (INIS)

    Weiss, S.

    2007-01-01

    Deformation quantization is an algebraic but still geometrical way to define noncommutative spacetimes. In order to investigate corresponding gauge theories on such spaces, the geometrical formulation in terms of principal fibre bundles yields the appropriate framework. In this talk I will explain what should be understood by a deformation quantization of principal fibre bundles and how associated vector bundles arise in this context. (author)

  14. Primary School Principals' Self-Monitoring Skills

    Science.gov (United States)

    Konan, Necdet

    2015-01-01

    The aim of the present study is to identify primary school principals' self-monitoring skills. The study adopted the general survey model and its population comprised primary school principals serving in the city of Diyarbakir, Turkey, while 292 of these constituted the sample. Self-Monitoring Scale was used as the data collection instrument. In…

  15. Revising the Role of Principal Supervisor

    Science.gov (United States)

    Saltzman, Amy

    2016-01-01

    In Washington, D.C., and Tulsa, Okla., districts whose efforts are supported by the Wallace Foundation, principal supervisors concentrate on bolstering their principals' work to improve instruction, as opposed to focusing on the managerial or operational aspects of running a school. Supervisors oversee fewer schools, which enables them to provide…

  16. An Examination of Principal Job Satisfaction

    Science.gov (United States)

    Pengilly, Michelle M.

    2010-01-01

    As education continues to succumb to deficits in budgets and increasingly high levels of student performance to meet the federal and state mandates, the quest to sustain and retain successful principals is imperative. The National Association of School Boards (1999) portrays effective principals as "linchpins" of school improvement and…

  17. Do Principals Fire the Worst Teachers?

    Science.gov (United States)

    Jacob, Brian A.

    2011-01-01

    This article takes advantage of a unique policy change to examine how principals make decisions regarding teacher dismissal. In 2004, the Chicago Public Schools (CPS) and Chicago Teachers Union signed a new collective bargaining agreement that gave principals the flexibility to dismiss probationary teachers for any reason and without the…

  18. Artful Dodges Principals Use to Beat Bureaucracy.

    Science.gov (United States)

    Ficklen, Ellen

    1982-01-01

    A study of Chicago (Illinois) principals revealed many ways principals practiced "creative insubordination"--avoiding following instructions but still getting things done. Among the dodges are deliberately missing deadlines, following orders literally, ignoring channels to procure teachers or materials, and using community members to…

  19. Women principals' reflections of curriculum management challenges ...

    African Journals Online (AJOL)

    This study reports the reflections of grade 6 rural primary principals in Mpumalanga province. A qualitative method of inquiry was used in this article, where data were collected using individual interviews with three principals and focus group discussions with the school management teams (SMTs) of three primary schools.

  20. The Succession of a School Principal.

    Science.gov (United States)

    Fauske, Janice R.; Ogawa, Rodney T.

    Applying theory from organizational and cultural perspectives to succession of principals, this study observes and records the language and culture of a small suburban elementary school. The study's procedures included analyses of shared organizational understandings as well as identification of the principal's influence on the school. Analyses of…

  1. Principals' Perceptions of School Public Relations

    Science.gov (United States)

    Morris, Robert C.; Chan, Tak Cheung; Patterson, Judith

    2009-01-01

    This study was designed to investigate school principals' perceptions on school public relations in five areas: community demographics, parental involvement, internal and external communications, school council issues, and community resources. Findings indicated that principals' concerns were as follows: rapid population growth, change of…

  2. Should Principals Know More about Law?

    Science.gov (United States)

    Doctor, Tyrus L.

    2013-01-01

    Educational law is a critical piece of the education conundrum. Principals reference law books on a daily basis in order to address the wide range of complex problems in the school system. A principal's knowledge of law issues and legal decision-making are essential to provide effective feedback for a successful school.

  3. How Not to Prepare School Principals

    Science.gov (United States)

    Davis, Stephen H.; Leon, Ronald J.

    2011-01-01

    Instead of focusing on how principals should be trained, an contrarian view is offered, grounded upon theoretical perspectives of experiential learning, and in particular, upon the theory of andragogy. A brief parable of the DoNoHarm School of Medicine is used as a descriptive analog for many principal preparation programs in America. The…

  4. Social Media Strategies for School Principals

    Science.gov (United States)

    Cox, Dan; McLeod, Scott

    2014-01-01

    The purpose of this qualitative study was to describe, analyze, and interpret the experiences of school principals who use multiple social media tools with stakeholders as part of their comprehensive communications practices. Additionally, it examined why school principals have chosen to communicate with their stakeholders through social media.…

  5. New Principals' Perspectives of Their Multifaceted Roles

    Science.gov (United States)

    Gentilucci, James L.; Denti, Lou; Guaglianone, Curtis L.

    2013-01-01

    This study utilizes Symbolic Interactionism to explore perspectives of neophyte principals. Findings explain how these perspectives are modified through complex interactions throughout the school year, and they also suggest preparation programs can help new principals most effectively by teaching "soft" skills such as active listening…

  6. The Principal's Guide to Grant Success.

    Science.gov (United States)

    Bauer, David G.

    This book provides principals of public and private elementary and middle schools with a step-by-step approach for developing a system that empowers faculty, staff, and the school community in attracting grant funds. Following the introduction, chapter 1 discusses the principal's role in supporting grantseeking. Chapter 2 describes how to…

  7. Symbiotic mutualism with a community of opportunistic ants: protection, competition, and ant occupancy of the myrmecophyte Barteria nigritana (Passifloraceae)

    Science.gov (United States)

    Djiéto-Lordon, Champlain; Dejean, Alain; Gibernau, Marc; Hossaert-McKey, Martine; McKey, Doyle

    2004-10-01

    Barteria nigritana is a myrmecophyte tree of Lower Guinea coastal vegetation. Unlike the more specialised B. fistulosa, which harbours a single host-specific mutualistic ant, B. nigritana is associated with several opportunistic ants. Such symbiotic, yet opportunistic, ant-plant associations have been little studied. On 113 clumps of B. nigritana, we censused ant associates and herbivores and compared herbivory on plants occupied by different ants. In addition to these correlative data, protection conferred by different ant species was compared by herbivore-placement experiments. Identity of ant associate changed predictably over plant ontogeny. Pheidole megacephala was restricted to very small plants; saplings were occupied by either Oecophylla longinoda or Crematogaster sp., and the latter species was the sole occupant of larger trees. Damage by caterpillars of the nymphalid butterfly Acraea zetes accounted for much of the herbivory to leaves. Ant species differed in the protection provided to hosts. While P. megacephala provided no significant protection, plants occupied by O. longinoda and Crematogaster sp. suffered less damage than did unoccupied plants or those occupied by P. megacephala. Furthermore, O. longinoda provided more effective protection than did Crematogaster sp. Herbivore-placement experiments confirmed these results. Workers of O. longinoda killed or removed all larval instars of A. zetes. Crematogaster preyed on only the two first larval instars, and P. megacephala preyed mainly on eggs, only rarely attacking the two first larval instars. Opportunistic ants provided significant protection to this relatively unspecialised myrmecophyte. The usual associate of mature trees was not the species that provided most protection.

  8. Selenium exposure results in reduced reproduction in an invasive ant species and altered competitive behavior for a native ant species

    International Nuclear Information System (INIS)

    De La Riva, Deborah G.; Trumble, John T.

    2016-01-01

    Competitive ability and numerical dominance are important factors contributing to the ability of invasive ant species to establish and expand their ranges in new habitats. However, few studies have investigated the impact of environmental contamination on competitive behavior in ants as a potential factor influencing dynamics between invasive and native ant species. Here we investigated the widespread contaminant selenium to investigate its potential influence on invasion by the exotic Argentine ant, Linepithema humile, through effects on reproduction and competitive behavior. For the fecundity experiment, treatments were provided to Argentine ant colonies via to sugar water solutions containing one of three concentrations of selenium (0, 5 and 10 μg Se mL −1 ) that fall within the range found in soil and plants growing in contaminated areas. Competition experiments included both the Argentine ant and the native Dorymyrmex bicolor to determine the impact of selenium exposure (0 or 15 μg Se mL −1 ) on exploitation- and interference-competition between ant species. The results of the fecundity experiment revealed that selenium negatively impacted queen survival and brood production of Argentine ants. Viability of the developing brood was also affected in that offspring reached adulthood only in colonies that were not given selenium, whereas those in treated colonies died in their larval stages. Selenium exposure did not alter direct competitive behaviors for either species, but selenium exposure contributed to an increased bait discovery time for D. bicolor. Our results suggest that environmental toxins may not only pose problems for native ant species, but may also serve as a potential obstacle for establishment among exotic species. - Highlights: • Argentine ant colonies exposed to selenium had reduced fecundity compared to unexposed colonies. • Viability of offspring was negatively impacted by selenium. • Queen survival was reduced in colonies

  9. The introduction history of invasive garden ants in Europe: integrating genetic, chemical and behavioural approaches

    DEFF Research Database (Denmark)

    Ugelvig, Line; Drijfhout, Falko; Kronauer, Daniel

    2008-01-01

    BACKGROUND: The invasive garden ant, Lasius neglectus, is the most recently detected pest ant and the first known invasive ant able to become established and thrive in the temperate regions of Eurasia. In this study, we aim to reconstruct the invasion history of this ant in Europe analysing 14 po...

  10. Stealthy invaders: the biology of Cardiocondyla tramp ants

    DEFF Research Database (Denmark)

    Heinze, J.; Cremer, Sylvia; Eckl, N.

    2006-01-01

    Many invasive ant species, such as the Argentine ant or the red imported fire ant, have huge colonies with thousands of mass-foraging workers, which quickly monopolise resources and therefore represent a considerable threat to the native ant fauna. Cardiocondyla obscurior and several other specie...

  11. FMR measurements in fire ants: evidence of magnetic material

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Darci M.S.; Acosta-Avalos, Daniel; El-Jaick, Lea J.; Cunha, Alexandra D.M.; Malheiros, Maria G.; Wajnberg, Eliane [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Linhares, Marilia P. [Centro de Ciencias do Estado, do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    1998-01-01

    Based on the behavioral and the localization of iron-containing tissue fire ants were examined by EPR for magnetic material. Results suggest the presence of magnetite particles. (author) 12 refs., 1 fig.

  12. Disease dynamics in a specialized parasite of ant societies.

    Directory of Open Access Journals (Sweden)

    Sandra B Andersen

    Full Text Available Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests and that hyperparasites often castrate Ophiocordyceps. However, once fruiting bodies become sexually mature they appear robust. Such parasite life-history traits are consistent with iteroparity--a reproductive strategy rarely considered in fungi. We discuss how tropical habitats with high biodiversity of hyperparasites and high spore mortality has likely been crucial for the evolution and maintenance of iteroparity in parasites with low dispersal potential.

  13. Sperm length evolution in the fungus-growing ants

    DEFF Research Database (Denmark)

    Baer, B.; Dijkstra, M. B.; Mueller, U. G.

    2009-01-01

    -growing ants, representing 9 of the 12 recognized genera, and mapped these onto the ant phylogeny. We show that average sperm length across species is highly variable and decreases with mature colony size in basal genera with singly mated queens, suggesting that sperm production or storage constraints affect...... the evolution of sperm length. Sperm length does not decrease further in multiply mating leaf-cutting ants, despite substantial further increases in colony size. In a combined analysis, sexual dimorphism explained 63.1% of the variance in sperm length between species. As colony size was not a significant...... predictor in this analysis, we conclude that sperm production trade-offs in males have been the major selective force affecting sperm length across the fungus-growing ants, rather than storage constraints in females. The relationship between sperm length and sexual dimorphism remained robust...

  14. Myrmeciza and related antbirds (Aves, Formicariidae as army ant followers

    Directory of Open Access Journals (Sweden)

    Edwin O. Willis

    1984-01-01

    Full Text Available Antbirds of the genera Myrmeciza (including Sipia and Myrmoborus, Gymnocichla, and Sclateria hop near or on the ground in fairly dense vegetation, "pounding" their tails downward. Where dense understory vegetation is widespread and ants move in it for long distances, certain of these antbirds become regular ant followers: M. immaculata and M. fortis in cluttered moist foothill forest from Costa Rica to upper Amazonia; Gymnocichla nudiceps in moist cluttered second growth of Central America to Colombia. Where the forest understory is more open, Myrmeciza species follow ants mainly in cluttered patches: M. exsul in lowland forest west of the Andes, M. myotherina east of the Andes. Myrmeciza or relatives that specialize on water-edge or very dense zones rarely follow ants.

  15. Ants farm subterranean aphids mostly in single clone groups

    DEFF Research Database (Denmark)

    Ivens, Aniek B.F.; Kronauer, Daniel Jan Christoph; Pen, Ido

    2012-01-01

    mutualisms have been studied in sufficient genetic detail to address these issues, so we decided to characterize symbiont diversity in the complex mutualism between multiple root aphid species and Lasius flavus ants. After showing elsewhere that three of these aphid species have low dispersal and mostly...... if not exclusively asexual reproduction, we here investigate aphid diversity within and between ant nest mounds. Results The three focal species (Geoica utricularia, Forda marginata and Tetraneura ulmi) had considerable clonal diversity at the population level. Yet more than half of the ant mounds contained just....... The ants appear to eat most of the early instar aphids, so that adult aphids are unlikely to face limited phloem resources and scramble competition with other aphids. We suggest that such culling of carbohydrate-providing symbionts for protein ingestion may maintain maximal host yield per aphid while also...

  16. Ant groups optimally amplify the effect of transiently informed individuals

    Science.gov (United States)

    Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Ghosh, Abhijit; Gov, Nir; Feinerman, Ofer

    2015-07-01

    To cooperatively transport a large load, it is important that carriers conform in their efforts and align their forces. A downside of behavioural conformism is that it may decrease the group's responsiveness to external information. Combining experiment and theory, we show how ants optimize collective transport. On the single-ant scale, optimization stems from decision rules that balance individuality and compliance. Macroscopically, these rules poise the system at the transition between random walk and ballistic motion where the collective response to the steering of a single informed ant is maximized. We relate this peak in response to the divergence of susceptibility at a phase transition. Our theoretical models predict that the ant-load system can be transitioned through the critical point of this mesoscopic system by varying its size; we present experiments supporting these predictions. Our findings show that efficient group-level processes can arise from transient amplification of individual-based knowledge.

  17. Florida alternative NTCIP testing software (ANTS) for actuated signal controllers.

    Science.gov (United States)

    2009-01-01

    The scope of this research project did include the development of a software tool to test devices for NTCIP compliance. Development of the Florida Alternative NTCIP Testing Software (ANTS) was developed by the research team due to limitations found w...

  18. Novel fungal disease in complex leaf-cutting ant societies

    DEFF Research Database (Denmark)

    Hughes, David Peter; Evans, Harry C.; Hywel-Jones, Nigel

    2009-01-01

    1. The leaf-cutting ants practise an advanced system of mycophagy where they grow a fungus as a food source. As a consequence of parasite threats to their crops, they have evolved a system of morphological, behavioural, and chemical defences, particularly against fungal pathogens (mycopathogens). 2....... Specific fungal diseases of the leaf-cutting ants themselves have not been described, possibly because broad spectrum anti-fungal defences against mycopathogens have reduced their susceptibility to entomopathogens. 3. Using morphological and molecular tools, the present study documents three rare infection...... events of Acromyrmex and Atta leaf-cutting ants by Ophiocordyceps fungi, agenus of entomopathogens that is normally highly specific in its host choice. 4. As leaf-cutting ants have been intensively studied, the absence of prior records of Ophiocordyceps suggests that these infections may be a novel event...

  19. Heavy metal pollution disturbs immune response in wild ant populations

    International Nuclear Information System (INIS)

    Sorvari, Jouni; Rantala, Liisa M.; Rantala, Markus J.; Hakkarainen, Harri; Eeva, Tapio

    2007-01-01

    Concern about the effects of environmental contaminants on immune function in both humans and wildlife is growing and practically nothing is known about this impact on terrestrial invertebrates, even though they are known to easily accumulate pollutants. We studied the effect of industrial heavy metal contamination on immune defense of a free-living wood ant (Formica aquilonia). To find out whether ants show an adapted immune function in a polluted environment, we compared encapsulation responses between local and translocated colonies. Local colonies showed higher heavy metal levels than the translocated ones but the encapsulation response was similar between the two groups, indicating that the immune system of local ants has not adapted to high contamination level. The encapsulation response was elevated in moderate whereas suppressed in high heavy metal levels suggesting higher risk for infections in heavily polluted areas. - Heavy metal pollution affects immune function in ants

  20. Ant colony search algorithm for optimal reactive power optimization

    Directory of Open Access Journals (Sweden)

    Lenin K.

    2006-01-01

    Full Text Available The paper presents an (ACSA Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents’ approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical test bus system. The proposed approach is tested and compared to genetic algorithm (GA, Adaptive Genetic Algorithm (AGA.

  1. application of ant colony optimisation in distribution transformer sizing

    African Journals Online (AJOL)

    HP

    Keywords: ant colony, optimization, transformer sizing, distribution transformer. 1. INTRODUCTION ... more intensive pheromone and higher probability to be chosen [12]. ..... pp.29-41, 1996. [7] EC global market place, “Technical Parameters”,.

  2. Fluid intake rates in ants correlate with their feeding habits.

    Science.gov (United States)

    Paul, J; Roces, F

    2003-04-01

    This study investigates the techniques of nectar feeding in 11 different ant species, and quantitatively compares fluid intake rates over a wide range of nectar concentrations in four species that largely differ in their feeding habits. Ants were observed to employ two different techniques for liquid food intake, in which the glossa works either as a passive duct-like structure (sucking), or as an up- and downwards moving shovel (licking). The technique employed for collecting fluids at ad libitum food sources was observed to be species-specific and to correlate with the presence or absence of a well-developed crop in the species under scrutiny. Workers of ponerine ants licked fluid food during foraging and transported it as a droplet between their mandibles, whereas workers of species belonging to phylogenetically more advanced subfamilies, with a crop capable of storing liquids, sucked the fluid food, such as formicine ants of the genus Camponotus. In order to evaluate the performance of fluid collection during foraging, intake rates for sucrose solutions of different concentrations were measured in four ant species that differ in their foraging ecology. Scaling functions between fluid intake rates and ant size were first established for the polymorphic species, so as to compare ants of different size across species. Results showed that fluid intake rate depended, as expected and previously reported in the literature, on sugar concentration and the associated fluid viscosity. It also depended on both the species-specific feeding technique and the extent of specialization on foraging on liquid food. For similarly-sized ants, workers of two nectar-feeding ant species, Camponotus rufipes (Formicinae) and Pachycondyla villosa (Ponerinae), collected fluids with the highest intake rates, while workers of the leaf-cutting ant Atta sexdens (Myrmicinae) and a predatory ant from the Rhytidoponera impressa-complex (Ponerinae) did so with the lowest rate. Calculating the

  3. Preparing Principals as Instructional Leaders: Perceptions of University Faculty, Expert Principals, and Expert Teacher Leaders

    Science.gov (United States)

    Taylor Backor, Karen; Gordon, Stephen P.

    2015-01-01

    Although research has established links between the principal's instructional leadership and student achievement, there is considerable concern in the literature concerning the capacity of principal preparation programs to prepare instructional leaders. This study interviewed educational leadership faculty as well as expert principals and teacher…

  4. Exploring the Impact of Applicants' Gender and Religion on Principals' Screening Decisions for Assistant Principal Applicants

    Science.gov (United States)

    Bon, Susan C.

    2009-01-01

    In this experimental study, a national random sample of high school principals (stratified by gender) were asked to evaluate hypothetical applicants whose resumes varied by religion (Jewish, Catholic, nondenominational) and gender (male, female) for employment as assistant principals. Results reveal that male principals rate all applicants higher…

  5. Principal Self-Efficacy and Work Engagement: Assessing a Norwegian Principal Self-Efficacy Scale

    Science.gov (United States)

    Federici, Roger A.; Skaalvik, Einar M.

    2011-01-01

    One purpose of the present study was to develop and test the factor structure of a multidimensional and hierarchical Norwegian Principal Self-Efficacy Scale (NPSES). Another purpose of the study was to investigate the relationship between principal self-efficacy and work engagement. Principal self-efficacy was measured by the 22-item NPSES. Work…

  6. Principal Time Management Skills: Explaining Patterns in Principals' Time Use, Job Stress, and Perceived Effectiveness

    Science.gov (United States)

    Grissom, Jason A.; Loeb, Susanna; Mitani, Hajime

    2015-01-01

    Purpose: Time demands faced by school principals make principals' work increasingly difficult. Research outside education suggests that effective time management skills may help principals meet job demands, reduce job stress, and improve their performance. The purpose of this paper is to investigate these hypotheses. Design/methodology/approach:…

  7. Climatic warming destabilizes forest ant communities.

    Science.gov (United States)

    Diamond, Sarah E; Nichols, Lauren M; Pelini, Shannon L; Penick, Clint A; Barber, Grace W; Cahan, Sara Helms; Dunn, Robert R; Ellison, Aaron M; Sanders, Nathan J; Gotelli, Nicholas J

    2016-10-01

    How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America. At the community level, warming consistently increased occupancy of nests and decreased extinction and nest abandonment. This consistency was largely driven by strong responses of a subset of thermophilic species at each site. As colonies of thermophilic species persisted in nests for longer periods of time under warmer temperatures, turnover was diminished, and species interactions were likely altered. We found that dynamical (Lyapunov) community stability decreased with warming both within and between sites. These results refute null expectations of simple temperature-driven increases in the activity and movement of thermophilic ectotherms. The reduction in stability under warming contrasts with the findings of previous studies that suggest resilience of species interactions to experimental and natural warming. In the face of warmer, no-analog climates, communities of the future may become increasingly fragile and unstable.

  8. Recognition in ants: social origin matters.

    Directory of Open Access Journals (Sweden)

    Joël Meunier

    Full Text Available The ability of group members to discriminate against foreigners is a keystone in the evolution of sociality. In social insects, colony social structure (number of queens is generally thought to influence abilities of resident workers to discriminate between nestmates and non-nestmates. However, whether social origin of introduced individuals has an effect on their acceptance in conspecific colonies remains poorly explored. Using egg-acceptance bioassays, we tested the influence of social origin of queen-laid eggs on their acceptance by foreign workers in the ant Formica selysi. We showed that workers from both single- and multiple-queen colonies discriminated against foreign eggs from single-queen colonies, whereas they surprisingly accepted foreign eggs from multiple-queen colonies. Chemical analyses then demonstrated that social origins of eggs and workers could be discriminated on the basis of their chemical profiles, a signal generally involved in nestmate discrimination. These findings provide the first evidence in social insects that social origins of eggs interfere with nestmate discrimination and are encoded by chemical signatures.

  9. Nasa's Ant-Inspired Swarmie Robots

    Science.gov (United States)

    Leucht, Kurt W.

    2016-01-01

    As humans push further beyond the grasp of earth, robotic missions in advance of human missions will play an increasingly important role. These robotic systems will find and retrieve valuable resources as part of an in-situ resource utilization (ISRU) strategy. They will need to be highly autonomous while maintaining high task performance levels. NASA Kennedy Space Center has teamed up with the Biological Computation Lab at the University of New Mexico to create a swarm of small, low-cost, autonomous robots to be used as a ground-based research platform for ISRU missions. The behavior of the robot swarm mimics the central-place foraging strategy of ants to find and collect resources in a previously unmapped environment and return those resources to a central site. This talk will guide the audience through the Swarmie robot project from its conception by students in a New Mexico research lab to its robot trials in an outdoor parking lot at NASA. The software technologies and techniques used on the project will be discussed, as well as various challenges and solutions that were encountered by the development team along the way.

  10. Carbohydrate supply limits invasion of natural communities by Argentine ants.

    Science.gov (United States)

    Rowles, Alexei D; Silverman, Jules

    2009-08-01

    The ability of species to invade new habitats is often limited by various biotic and physical factors or interactions between the two. Invasive ants, frequently associated with human activities, flourish in disturbed urban and agricultural environments. However, their ability to invade and establish in natural habitats is more variable. This is particularly so for the invasive Argentine ant (Linepithema humile). While biotic resistance and low soil moisture limits their invasion of natural habitats in some instances, the effect of food availability has been poorly explored. We conducted field experiments to determine if resource availability limits the spread and persistence of Argentine ants in remnant natural forest in North Carolina. Replicated transects paired with and without sucrose solution feeding stations were run from invaded urban edges into forest remnants and compared over time using baits and direct counts at feeding stations. Repeated under different timing regimes in 2006 and 2007, access to sucrose increased local Argentine ant abundances (1.6-2.5 fold) and facilitated their progression into the forest up to 73 +/- 21% of 50-m transects. Resource removal caused an expected decrease in Argentine ant densities in 2006, in conjunction with their retreat to the urban/forest boundary. However, in 2007, Argentine ant numbers unexpectedly continued to increase in the absence of sugar stations, possibly through access to alternative resources or conditions not available the previous year such as honeydew-excreting Hemiptera. Our results showed that supplementing carbohydrate supply facilitates invasion of natural habitat by Argentine ants. This is particularly evident where Argentine ants continued to thrive following sugar station removal.

  11. Hybridization in East African swarm-raiding army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel Jc; Peters, Marcell K; Schöning, Caspar

    2011-01-01

    Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied...... hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites....

  12. An Improved Ant Colony Matching by Using Discrete Curve Evolution

    OpenAIRE

    Saadi, Younes; Sari, Eka,; Herawan, Tutut

    2014-01-01

    Part 1: Information & Communication Technology-EurAsia Conference 2014, ICT-EurAsia 2014; International audience; In this paper we present an improved Ant Colony Optimization (ACO) for contour matching, which can be used to match 2D shapes. Discrete Curve Evolution (DCE) technique is used to simplify the extracted contour. In order to find the best correspondence between shapes, the match process is formulated as a Quadratic Assignment Problem (QAP) and resolved by using Ant Colony Optimizati...

  13. Behavior of ergatoid males in the ant, Cardiocondyla nuda

    OpenAIRE

    Heinze, Jürgen; Künholz, S.; Schilder, K.; Hölldobler, B.

    1993-01-01

    Ergatoid males of the ant, Cardiocondyla nuda, attack and frequently kill young males during or shortly after eclosion. Smaller colonies therefore contain typically only one adult male, which may inseminate all alate queens which are reared in the colony over a few weeks. In larger colonies, several males may be present, however, fighting among adult males was not observed. We discuss the significance of male fighting behavior in ants.

  14. Trail Pheromone Disruption of Argentine Ant Trail Formation and Foraging

    Science.gov (United States)

    Suckling, D.M.; Peck, R.W.; Stringer, L.D.; Snook, K.; Banko, P.C.

    2010-01-01

    Trail pheromone disruption of invasive ants is a novel tactic that builds on the development of pheromone-based pest management in other insects. Argentine ant trail pheromone, (Z)-9-hexadecenal, was formulated as a micro-encapsulated sprayable particle and applied against Argentine ant populations in 400 m2 field plots in Hawai'i Volcanoes National Park. A widely dispersed point source strategy for trail pheromone disruption was used. Traffic rates of ants in bioassays of treated filter paper, protected from rainfall and sunlight, indicated the presence of behaviorally significant quantities of pheromone being released from the formulation for up to 59 days. The proportion of plots, under trade wind conditions (2-3 m s-1), with visible trails was reduced for up to 14 days following treatment, and the number of foraging ants at randomly placed tuna-bait cards was similarly reduced. The success of these trail pheromone disruption trials in a natural ecosystem highlights the potential of this method for control of invasive ant species in this and other environments. ?? Springer Science+Business Media, LLC 2010.

  15. No sex in fungus-farming ants or their crops.

    Science.gov (United States)

    Himler, Anna G; Caldera, Eric J; Baer, Boris C; Fernández-Marín, Hermógenes; Mueller, Ulrich G

    2009-07-22

    Asexual reproduction imposes evolutionary handicaps on asexual species, rendering them prone to extinction, because asexual reproduction generates novel genotypes and purges deleterious mutations at lower rates than sexual reproduction. Here, we report the first case of complete asexuality in ants, the fungus-growing ant Mycocepurus smithii, where queens reproduce asexually but workers are sterile, which is doubly enigmatic because the clonal colonies of M. smithii also depend on clonal fungi for food. Degenerate female mating anatomy, extensive field and laboratory surveys, and DNA fingerprinting implicate complete asexuality in this widespread ant species. Maternally inherited bacteria (e.g. Wolbachia, Cardinium) and the fungal cultivars can be ruled out as agents inducing asexuality. M. smithii societies of clonal females provide a unique system to test theories of parent-offspring conflict and reproductive policing in social insects. Asexuality of both ant farmer and fungal crop challenges traditional views proposing that sexual farmer ants outpace coevolving sexual crop pathogens, and thus compensate for vulnerabilities of their asexual crops. Either the double asexuality of both farmer and crop may permit the host to fully exploit advantages of asexuality for unknown reasons or frequent switching between crops (symbiont reassociation) generates novel ant-fungus combinations, which may compensate for any evolutionary handicaps of asexuality in M. smithii.

  16. [Ants as carriers of microorganisms in hospital environments].

    Science.gov (United States)

    Pereira, Rogério Dos Santos; Ueno, Mariko

    2008-01-01

    Concern exists regarding the real possibility of public health threats caused by pathogenic agents that are carried by urban ants. The present study had the objective of isolating and identifying the microorganisms that are associated with ants in hospital environments. One hundred and twenty-five ants of the same species were collected from different units of a university hospital. Each ant was collected using a swab soaked with physiological solution and was transferred to a tube containing brain heart infusion broth and incubated at 35 degrees C for 24 hours. From each tube, with growth, inoculations were made into specific culturing media, to isolate any microorganisms. The ants presented a high capacity for carrying microorganism groups: spore-producing Gram-positive bacilli 63.5%, Gram-negative bacilli 6.3%, Gram-positive cocci 23.1%, filamentous fungi 6.7% and yeast 0.5%. Thus, it can be inferred that ants may be one of the agents responsible for disseminating microorganisms in hospital environments.

  17. Species-Specific Effects of Ant Inhabitants on Bromeliad Nutrition.

    Directory of Open Access Journals (Sweden)

    Ana Z Gonçalves

    Full Text Available Predator activities may lead to the accumulation of nutrients in specific areas of terrestrial habitats where they dispose of prey carcasses. In their feeding sites, predators may increase nutrient availability in the soil and favor plant nutrition and growth. However, the translocation of nutrients from one habitat to another may depend on predator identity and diet, as well as on the amount of prey intake. Here we used isotopic (15N and physiological methods in greenhouse experiments to evaluate the effects of the identity of predatory ants (i.e., the consumption of prey and nest sites on the nutrition and growth of the bromeliad Quesnelia arvensis. We showed that predatory ants with protein-based nutrition (i.e., Odontomachus hastatus, Gnamptogenys moelleri improved the performance of their host bromeliads (i.e., increased foliar N, production of soluble proteins and growth. On the other hand, the contribution of Camponotus crassus for the nutritional status of bromeliads did not differ from bromeliads without ants, possibly because this ant does not have arthropod prey as a preferred food source. Our results show, for the first time, that predatory ants can translocate nutrients from one habitat to another within forests, accumulating nutrients in their feeding sites that become available to bromeliads. Additionally, we highlight that ant contribution to plant nutrition may depend on predator identity and its dietary requirements. Nest debris may be especially important for epiphytic and terrestrial bromeliads in nutrient-poor environments.

  18. Reaction of mutualistic and granivorous ants to ulex elaiosome chemicals.

    Science.gov (United States)

    Gammans, Nicola; Bullock, James M; Gibbons, Hannah; Schönrogge, Karsten

    2006-09-01

    It has been proposed that chemicals on plant elaiosomes aid seed detection by seed-dispersing ants. We hypothesized that the chemical interaction between ants and elaiosomes is more intimate than a generic attraction, and that elaiosome chemicals will attract mutualistic but not granivorous ant species. We investigated this by using two gorse species, Ulex minor and U. europaeus, and two associated ant species from European heathlands, the mutualist Myrmica ruginodis and the granivore Tetramorium caespitum. Behavioral studies were conducted with laboratory nests and foraging arenas. Both ants will take Ulex seeds, but while M. ruginodis showed increased antennation toward ether extracts of elaiosome surface chemicals compared with controls, T. caespitum showed no response. Elaiosome extracts were separated into seven lipid fractions. M. ruginodis showed increased antennation only toward the diglyceride fractions of both Ulex species, whereas T. caespitum showed no consistent reaction. This indicates that M. ruginodis can detect the elaiosome by responding to its surface chemicals, but T. caespitum is unresponsive to these chemicals. Responses to surface chemicals could increase the rate of seed detection in the field, and so these results suggest that Ulex elaiosomes produce chemicals that facilitate attraction of mutualistic rather than granivorous ant species. This could reduce seed predation and increase Ulex fitness.

  19. Aversive learning of odor-heat associations in ants.

    Science.gov (United States)

    Desmedt, Lucie; Baracchi, David; Devaud, Jean-Marc; Giurfa, Martin; d'Ettorre, Patrizia

    2017-12-15

    Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region because of their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as the unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit a conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general. © 2017. Published by The Company of Biologists Ltd.

  20. Competence of Litter Ants for Rapid Biodiversity Assessments

    Directory of Open Access Journals (Sweden)

    T. H. Saumya E. Silva

    2017-01-01

    Full Text Available Rapid Biodiversity Assessment approaches associated with focusing taxa have overcome many of the problems related to large scale surveys. This study examined the suitability of litter ants as a focusing taxon by checking whether diversity and species assemblages of litter ants reflect the overall picture of arthropod diversity and assemblages in leaf litter in two vegetation types: secondary forest and pine plantation in Upper Hanthana forest reserve, Sri Lanka. In each vegetation type, arthropods were sampled using three sampling methods (Winkler extraction, hand collection, and pitfall traps along three 100 m line transects. From the two sites, 1887 litter ants (34 species and 3488 litter arthropods (52 species were collected. Species assemblages composition of both ants and other arthropods differed significantly between the two sites (ANOSIM, p=0.001 with both groups generating distinct clusters for the two sites (SIMPROF, p=0.001. But there was no significant correlation (p>0.05 between abundance and richness of litter ants and those of other arthropods in both vegetation types. The overall finding suggests that the litter ants do not reflect the holistic picture of arthropod diversity and assemblages in leaf litter, but the quality of the habitat for the survival of all litter arthropods.

  1. Water stress strengthens mutualism among ants, trees, and scale insects.

    Directory of Open Access Journals (Sweden)

    Elizabeth G Pringle

    2013-11-01

    Full Text Available Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  2. An invasive slug exploits an ant-seed dispersal mutualism.

    Science.gov (United States)

    Meadley Dunphy, Shannon A; Prior, Kirsten M; Frederickson, Megan E

    2016-05-01

    Plant-animal mutualisms, such as seed dispersal, are often vulnerable to disruption by invasive species. Here, we show for the first time how a non-ant invasive species negatively affects seed dispersal by ants. We examined the effects of several animal species that co-occur in a temperate deciduous forest-including native and invasive seed-dispersing ants (Aphaenogaster rudis and Myrmica rubra, respectively), an invasive slug (Arion subfuscus), and native rodents-on a native myrmecochorous plant, Asarum canadense. We experimentally manipulated ant, slug, and rodent access to seed depots and measured seed removal. We also video-recorded depots to determine which other taxa interact with seeds. We found that A. rudis was the main disperser of seeds and that A. subfuscus consumed elaiosomes without dispersing seeds. Rodent visitation was rare, and rodent exclusion had no significant effect on seed or elaiosome removal. We then used data obtained from laboratory and field mesocosm experiments to determine how elaiosome robbing by A. subfuscus affects seed dispersal by A. rudis and M. rubra. We found that elaiosome robbing by slugs reduced seed dispersal by ants, especially in mesocosms with A. rudis, which picks up seeds more slowly than M. rubra. Taken together, our results show that elaiosome robbing by an invasive slug reduces seed dispersal by ants, suggesting that invasive slugs can have profound negative effects on seed dispersal mutualisms.

  3. Water stress strengthens mutualism among ants, trees, and scale insects.

    Science.gov (United States)

    Pringle, Elizabeth G; Akçay, Erol; Raab, Ted K; Dirzo, Rodolfo; Gordon, Deborah M

    2013-11-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  4. Incomplete Homogenization of Chemical Recognition Labels Between Formica sanguinea and Formica rufa Ants (Hymenoptera: Formicidae) Living in a Mixed Colony

    Science.gov (United States)

    Włodarczyk, Tomasz; Szczepaniak, Lech

    2014-01-01

    Abstract Formica sanguinea Latreille (Hymenoptera: Formicidae) is a slave-making species, i.e., it raids colonies of host species and pillages pupae, which are taken to develop into adult workers in a parasite colony. However, it has been unclear if the coexistence of F. sanguinea with slave workers requires uniformity of cuticular hydrocarbons (CHCs), among which those other than n -alkanes are believed to be the principal nestmate recognition cues utilized by ants. In this study, a mixed colony (MC) of F. sanguinea and Formica rufa L. as a slave species was used to test the hypothesis that CHCs are exchanged between the species. Chemical analysis of hexane extracts from ants’ body surfaces provided evidence for interspecific exchange of alkenes and methyl-branched alkanes. This result was confirmed by behavioral tests during which ants exhibited hostility toward conspecific individuals from the MC but not toward ones from homospecific colonies of their own species. However, it seems that species-specific differences in chemical recognition labels were not eliminated completely because ants from the MC were treated differently depending on whether they were con- or allospecific to the individuals whose behavioral reactions were tested. These findings are discussed in the context of mechanisms of colony's odor formation and effective integration of slaves into parasite colony. PMID:25502026

  5. CO2 efflux from subterranean nests of ant communities in a seasonal tropical forest, Thailand

    OpenAIRE

    Hasin, Sasitorn; Ohashi, Mizue; Yamada, Akinori; Hashimoto, Yoshiaki; Tasen, Wattanachai; Kume, Tomonori; Yamane, Seiki

    2014-01-01

    Many ant species construct subterranean nests. The presence of their nests may explain soil respiration “hot spots”, an important factor in the high CO2 efflux from tropical forests. However, no studies have directly measured CO2 efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO2 efflux from subterranean ant nests in a tropical seasonal forest, Thailand. We examined differences in nest CO2 efflux among ant species. We determi...

  6. Using ant-behavior-based simulation model AntWeb to improve website organization

    Science.gov (United States)

    Li, Weigang; Pinheiro Dib, Marcos V.; Teles, Wesley M.; Morais de Andrade, Vlaudemir; Alves de Melo, Alba C. M.; Cariolano, Judas T.

    2002-03-01

    Some web usage mining algorithms showed the potential application to find the difference among the organizations expected by visitors to the website. However, there are still no efficient method and criterion for a web administrator to measure the performance of the modification. In this paper, we developed an AntWeb, a model inspired by ants' behavior to simulate the sequence of visiting the website, in order to measure the efficient of the web structure. We implemented a web usage mining algorithm using backtrack to the intranet website of the Politec Informatic Ltd., Brazil. We defined throughput (the number of visitors to reach their target pages per time unit relates to the total number of visitors) as an index to measure the website's performance. We also used the link in a web page to represent the effect of visitors' pheromone trails. For every modification in the website organization, for example, putting a link from the expected location to the target object, the simulation reported the value of throughput as a quick answer about this modification. The experiment showed the stability of our simulation model, and a positive modification to the intranet website of the Politec.

  7. Comparative Analysis of Principals' Management Strategies in ...

    African Journals Online (AJOL)

    It was recommended among others that principals of secondary schools should adopt all the management strategies in this study as this will improve school administration and consequently students‟ academic performance. Keywords: Management Strategies; Secondary Schools; Administrative Effectiveness ...

  8. Spatial control of groundwater contamination, using principal ...

    Indian Academy of Sciences (India)

    probe into the spatial controlling processes of groundwater contamination, using principal component analysis (PCA). ... topography, soil type, depth of water levels, and water usage. Thus, the ... of effective sites for infiltration of recharge water.

  9. The Relationship between Principals' Managerial Approaches and ...

    African Journals Online (AJOL)

    Nekky Umera

    Egerton University, P. O. Box 16568, NAKURU KENYA bosirej@yahoo.com ... teacher and parental input while it was negatively correlated with the level of .... principal's attitude, gender qualifications, and leadership experience (Green,. 1999 ...

  10. First-Year Principal Encounters Homophobia

    Science.gov (United States)

    Retelle, Ellen

    2011-01-01

    A 1st-year principal encounters homonegativity and an ethical dilemma when she attempts to terminate a teacher because of the teacher's inadequate and ineffective teaching. The teacher responds by threatening to "out" Ms. L. to the parents.

  11. Integrating Data Transformation in Principal Components Analysis

    KAUST Repository

    Maadooliat, Mehdi; Huang, Jianhua Z.; Hu, Jianhua

    2015-01-01

    Principal component analysis (PCA) is a popular dimension reduction method to reduce the complexity and obtain the informative aspects of high-dimensional datasets. When the data distribution is skewed, data transformation is commonly used prior

  12. Spatial control of groundwater contamination, using principal

    Indian Academy of Sciences (India)

    Spatial control of groundwater contamination, using principal component analysis ... anthropogenic (agricultural activities and domestic wastewaters), and marine ... The PC scores reflect the change of groundwater quality of geogenic origin ...

  13. Principal Hawaiian Islands Geoid Heights (GEOID96)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' geoid height grid for the Principal Hawaiian Islands is distributed as a GEOID96 model. The computation used 61,000 terrestrial and marine gravity data held...

  14. Population Development of Several Species of Ants on the Cocoa Trees in South Sulawesi

    Directory of Open Access Journals (Sweden)

    Fatahuddin Fatahuddin

    2010-08-01

    Full Text Available Several species of ants with different behavior have been found in cocoa plantations and their behavior is important to be considered because it might be correlated with the degree of protection of cocoa plant from cocoa pests. The aim of this research is to manipulate and to develop ants population in environment, so they are able to establish permanently in cocoa trees. This research was conducted in Papakaju Regions Luwu Regency in Juli to November 2009. In this study, 10 cocoa trees with ants were sampled (each species of ant in 10 cocoa trees. A control of 10 tree samples without ant was also taken. In order to assess the abundance of ant population, it was grouped based on scoring, which score 1 for less than 20 ants, score 2 for 21–50 ants, score 3 for 51–200 ants, score 4 for 201–1000 ants, and score 5 for more than 1000 per tree. The results indicated that average of population score of the three ants species reached the highest population for the Oecophylla. smaragdina with average score 4.85 (>1000 ants, Dolichoderus thoracicus, with average score 3.90 (> 200 ants and Crematogaster. difformis with average score 3.10 (>200 ants. This research indicated that three species of ants, Oecophylla smaragdina (weaver ant, Dolichoderus thoracicus (cocoa black ant and Crematogaster difformis (cracking ant. in farmer cocoa plantations in South Sulawesi giving better performance against major pests of cocoa in particular cocoa pod borer (CPB. Key words: Ant Population, Oecophylla smaragdina, Dolichoderus thoracicus, Crematogaster difformis, artificial nest, cocoa.

  15. Report of the 4th European Zebrafish Principal Investigator Meeting.

    Science.gov (United States)

    Lopes, Susana S; Distel, Martin; Linker, Claudia; Fior, Rita; Monteiro, Rui; Bianco, Isaac H; Portugues, Ruben; Strähle, Uwe; Saúde, Leonor

    2016-12-01

    The European Zebrafish Principal Investigator Meeting (EZPM) is an ideal forum for group leaders using this fantastic animal model not only to discuss science but also to strengthen their interactions, to push forward technological advances, and to define guidelines for the use of this fish in research. The city of Lisbon (Portugal) was voted by the European group leaders to be the setting for the 4th EZPM, and the organizing committee, composed by Leonor Saúde (iMM Lisboa, PT), Susana Lopes (CEDOC, PT), Michael Orger (Champalimaud Foundation, PT), Rui Oliveira (ISPA, PT), and António Jacinto (CEDOC, PT), was very enthusiastic to organize a productive event. The 4th EZPM took place from March 15 to 19 at Pavilhão do Conhecimento, a Science Museum and Educational Center winner of The Great Prize FAD of Arquitecture 1999 and The Society for Environmental Graphic Design Award 2011. Over 5 days, 135 group leaders (89 men and 46 women) coming from 19 different European countries and also from the United States, Turkey, Israel, Chile, and Singapore presented and discussed their recent research achievements. In addition to the scientific oral and poster presentations, the group leaders gathered in very lively community sessions on morphants versus mutants (chaired by Didier Stainier, Max Planck Institute for Heart and Lung Research, DE), funding issues (chaired by Uwe Strahle, KIT-ITG, DE), and gender equality (chaired by Corinne Houart, KCL, United Kingdom). One of the highlights of the 4th EZPM was the guided visit to Oceanário de Lisboa, an international award-winning place that celebrates life with a stunning display of living aquatic creatures.

  16. Various chemical strategies to deceive ants in three Arhopala species (lepidoptera: Lycaenidae exploiting Macaranga myrmecophytes.

    Directory of Open Access Journals (Sweden)

    Yoko Inui

    Full Text Available Macaranga myrmecophytes (ant-plants are generally well protected from herbivore attacks by their symbiotic ants (plant-ants. However, larvae of Arhopala (Lepidoptera: Lycaenidae species survive and develop on specific Macaranga ant-plant species without being attacked by the plant-ants of their host species. We hypothesized that Arhopala larvae chemically mimic or camouflage themselves with the ants on their host plant so that the larvae are accepted by the plant-ant species of their host. Chemical analyses of cuticular hydrocarbons showed that chemical congruency varied among Arhopala species; A. dajagaka matched well the host plant-ants, A. amphimuta did not match, and unexpectedly, A. zylda lacked hydrocarbons. Behaviorally, the larvae and dummies coated with cuticular chemicals of A. dajagaka were well attended by the plant-ants, especially by those of the host. A. amphimuta was often attacked by all plant-ants except for the host plant-ants toward the larvae, and those of A. zylda were ignored by all plant-ants. Our results suggested that conspicuous variations exist in the chemical strategies used by the myrmecophilous butterflies that allow them to avoid ant attack and be accepted by the plant-ant colonies.

  17. Neuromodulation of Nestmate Recognition Decisions by Pavement Ants.

    Directory of Open Access Journals (Sweden)

    Andrew N Bubak

    Full Text Available Ant colonies are distributed systems that are regulated in a non-hierarchical manner. Without a central authority, individuals inform their decisions by comparing information in local cues to a set of inherent behavioral rules. Individual behavioral decisions collectively change colony behavior and lead to self-organization capable of solving complex problems such as the decision to engage in aggressive societal conflicts with neighbors. Despite the relevance to colony fitness, the mechanisms that drive individual decisions leading to cooperative behavior are not well understood. Here we show how sensory information, both tactile and chemical, and social context-isolation, nestmate interaction, or fighting non-nestmates-affects brain monoamine levels in pavement ants (Tetramorium caespitum. Our results provide evidence that changes in octopamine and serotonin in the brains of individuals are sufficient to alter the decision by pavement ants to be aggressive towards non-nestmate ants whereas increased brain levels of dopamine correlate to physical fighting. We propose a model in which the changes in brain states of many workers collectively lead to the self-organization of societal aggression between neighboring colonies of pavement ants.

  18. Neuromodulation of Nestmate Recognition Decisions by Pavement Ants.

    Science.gov (United States)

    Bubak, Andrew N; Yaeger, Jazmine D W; Renner, Kenneth J; Swallow, John G; Greene, Michael J

    2016-01-01

    Ant colonies are distributed systems that are regulated in a non-hierarchical manner. Without a central authority, individuals inform their decisions by comparing information in local cues to a set of inherent behavioral rules. Individual behavioral decisions collectively change colony behavior and lead to self-organization capable of solving complex problems such as the decision to engage in aggressive societal conflicts with neighbors. Despite the relevance to colony fitness, the mechanisms that drive individual decisions leading to cooperative behavior are not well understood. Here we show how sensory information, both tactile and chemical, and social context-isolation, nestmate interaction, or fighting non-nestmates-affects brain monoamine levels in pavement ants (Tetramorium caespitum). Our results provide evidence that changes in octopamine and serotonin in the brains of individuals are sufficient to alter the decision by pavement ants to be aggressive towards non-nestmate ants whereas increased brain levels of dopamine correlate to physical fighting. We propose a model in which the changes in brain states of many workers collectively lead to the self-organization of societal aggression between neighboring colonies of pavement ants.

  19. Ants avoid superinfections by performing risk-adjusted sanitary care.

    Science.gov (United States)

    Konrad, Matthias; Pull, Christopher D; Metzler, Sina; Seif, Katharina; Naderlinger, Elisabeth; Grasse, Anna V; Cremer, Sylvia

    2018-03-13

    Being cared for when sick is a benefit of sociality that can reduce disease and improve survival of group members. However, individuals providing care risk contracting infectious diseases themselves. If they contract a low pathogen dose, they may develop low-level infections that do not cause disease but still affect host immunity by either decreasing or increasing the host's vulnerability to subsequent infections. Caring for contagious individuals can thus significantly alter the future disease susceptibility of caregivers. Using ants and their fungal pathogens as a model system, we tested if the altered disease susceptibility of experienced caregivers, in turn, affects their expression of sanitary care behavior. We found that low-level infections contracted during sanitary care had protective or neutral effects on secondary exposure to the same (homologous) pathogen but consistently caused high mortality on superinfection with a different (heterologous) pathogen. In response to this risk, the ants selectively adjusted the expression of their sanitary care. Specifically, the ants performed less grooming and more antimicrobial disinfection when caring for nestmates contaminated with heterologous pathogens compared with homologous ones. By modulating the components of sanitary care in this way the ants acquired less infectious particles of the heterologous pathogens, resulting in reduced superinfection. The performance of risk-adjusted sanitary care reveals the remarkable capacity of ants to react to changes in their disease susceptibility, according to their own infection history and to flexibly adjust collective care to individual risk.

  20. PARAMETER ESTIMATION OF VALVE STICTION USING ANT COLONY OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    S. Kalaivani

    2012-07-01

    Full Text Available In this paper, a procedure for quantifying valve stiction in control loops based on ant colony optimization has been proposed. Pneumatic control valves are widely used in the process industry. The control valve contains non-linearities such as stiction, backlash, and deadband that in turn cause oscillations in the process output. Stiction is one of the long-standing problems and it is the most severe problem in the control valves. Thus the measurement data from an oscillating control loop can be used as a possible diagnostic signal to provide an estimate of the stiction magnitude. Quantification of control valve stiction is still a challenging issue. Prior to doing stiction detection and quantification, it is necessary to choose a suitable model structure to describe control-valve stiction. To understand the stiction phenomenon, the Stenman model is used. Ant Colony Optimization (ACO, an intelligent swarm algorithm, proves effective in various fields. The ACO algorithm is inspired from the natural trail following behaviour of ants. The parameters of the Stenman model are estimated using ant colony optimization, from the input-output data by minimizing the error between the actual stiction model output and the simulated stiction model output. Using ant colony optimization, Stenman model with known nonlinear structure and unknown parameters can be estimated.

  1. New fossil ants in French Cretaceous amber (Hymenoptera: Formicidae)

    Science.gov (United States)

    Perrichot, Vincent; Nel, André; Néraudeau, Didier; Lacau, Sébastien; Guyot, Thierry

    2008-02-01

    Recent studies on the ant phylogeny are mainly based on the molecular analyses of extant subfamilies and do not include the extinct, only Cretaceous subfamily Sphecomyrminae. However, the latter is of major importance for ant relationships, as it is considered the most basal subfamily. Therefore, each new discovery of a Mesozoic ant is of high interest for improving our understanding of their early history and basal relationships. In this paper, a new sphecomyrmine ant, allied to the Burmese amber genus Haidomyrmex, is described from mid-Cretaceous amber of France as Haidomyrmodes mammuthus gen. and sp. n. The diagnosis of the tribe Haidomyrmecini is emended based on the new type material, which includes a gyne (alate female) and two incomplete workers. The genus Sphecomyrmodes, hitherto known by a single species from Burmese amber, is also reported and a new species described as S. occidentalis sp. n. after two workers remarkably preserved in a single piece of Early Cenomanian French amber. The new fossils provide additional information on early ant diversity and relationships and demonstrate that the monophyly of the Sphecomyrminae, as currently defined, is still weakly supported.

  2. The cavity-nest ant Temnothorax crassispinus prefers larger nests.

    Science.gov (United States)

    Mitrus, S

    Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm 3 , respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm 3 nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

  3. Polarized light use in the nocturnal bull ant, Myrmecia midas.

    Science.gov (United States)

    Freas, Cody A; Narendra, Ajay; Lemesle, Corentin; Cheng, Ken

    2017-08-01

    Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarized light during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas . We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarized light change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1-2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts.

  4. Stigmergic construction and topochemical information shape ant nest architecture.

    Science.gov (United States)

    Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

    2016-02-02

    The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.

  5. DATA MINING UNTUK KLASIFIKASI PELANGGAN DENGAN ANT COLONY OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    Maulani Kapiudin

    2007-01-01

    Full Text Available In this research the system for potentially customer classification is designed by extracting rule based classification from raw data with certain criteria. The searching process uses customer database from a bank with data mining technic by using ant colony optimization. A test based on min_case_per_rule variety and phenomene updating were done on a certain period of time. The result are group of customer class which base on rules built by ant and by modifying the pheromone updating, the area of the case is getting bigger. Prototype of the software is coded with C++ 6 version. The customer database master is created by using Microsoft Access. This paper gives information about potential customer of bank that can be classified by prototype of the software. Abstract in Bahasa Indonesia : Pada penelitian untuk sistem klasifikasi potensial customer ini didesain dengan melakukan ekstrak rule berdasarkan klasifikasi dari data mentah dengan kriteria tertentu. Proses pencarian menggunakan database pelanggan dari suatu bank dengan teknik data mining dengan ant colony optimization. Dilakukan percobaan dengan min_case_per_rule variety dan phenomene updating pada periode waktu tertentu. Hasilnya adalah sekelompok class pelanggan yang didasarkan dari rules yang dibangun dengan ant dan dengan dimodifikasi dengan pheromone updating, area permasalahan menjadi lebih melebar. Prototype dari software ini menggunakan C++ versi 6. Database pelanggan dibangun dengan Microsoft Access. Paper ini memberikan informasi mengenai potensi pelanggan dari bank, sehingga dapat diklasifikasikan dengan prototype dari software. Kata kunci: ant colony optimization, classification, min_case_per_rule, term, pheromone updating

  6. Channeler Ant Model: 3 D segmentation of medical images through ant colonies

    International Nuclear Information System (INIS)

    Fiorina, E.; Valzano, S.; Arteche Diaz, R.; Bosco, P.; Gargano, G.; Megna, R.; Oppedisano, C.; Massafra, A.

    2011-01-01

    In this paper the Channeler Ant Model (CAM) and some results of its application to the analysis of medical images are described. The CAM is an algorithm able to segment 3 D structures with different shapes, intensity and background. It makes use of virtual and colonies and exploits their natural capabilities to modify the environment and communicate with each other by pheromone deposition. Its performance has been validated with the segmentation of 3 D artificial objects and it has been already used successfully in lung nodules detection on Computer Tomography images. This work tries to evaluate the CAM as a candidate to solve the quantitative segmentation problem in Magnetic Resonance brain images: to evaluate the percentage of white matter, gray matter and cerebrospinal fluid in each voxel.

  7. Promoting principals' managerial involvement in instructional improvement.

    Science.gov (United States)

    Gillat, A

    1994-01-01

    Studies of school leadership suggest that visiting classrooms, emphasizing achievement and training, and supporting teachers are important indicators of the effectiveness of school principals. The utility of a behavior-analytic program to support the enhancement of these behaviors in 2 school principals and the impact of their involvement upon teachers' and students' performances in three classes were examined in two experiments, one at an elementary school and another at a secondary school. Treatment conditions consisted of helping the principal or teacher to schedule his or her time and to use goal setting, feedback, and praise. A withdrawal design (Experiment 1) and a multiple baseline across classrooms (Experiment 2) showed that the principal's and teacher's rates of praise, feedback, and goal setting increased during the intervention, and were associated with improvements in the academic performance of the students. In the future, school psychologists might analyze the impact of involving themselves in supporting the principal's involvement in improving students' and teachers' performances or in playing a similar leadership role themselves.

  8. Regulation and specificity of antifungal metapleural gland secretion in leaf-cutting ants

    DEFF Research Database (Denmark)

    Yek, Sze Huei; Nash, David Richard; Jensen, Annette Bruun

    2012-01-01

    significantly larger for ants challenged with virulent and mild pathogens/weeds than for controls and Escovopsis-challenged ants. We conclude that the MG defence system of leaf-cutting ants has characteristics reminiscent of an additional cuticular immune system, with specific and non-specific components......Ants have paired metapleural glands (MGs) to produce secretions for prophylactic hygiene. These exocrine glands are particularly well developed in leaf-cutting ants, but whether the ants can actively regulate MG secretion is unknown. In a set of controlled experiments using conidia of five fungi...

  9. Influence of glutamine on morphological and functional changes of liver in the presence of extrahepatic biliary obstruction in rats Influência da glutamina em alterações funcionais e morfológicas do fígado na vigência de obstrução biliar extra-hepática em ratos

    Directory of Open Access Journals (Sweden)

    Manoel Camelo de Paiva Neto

    2010-08-01

    Full Text Available PURPOSE: To study the influence of glutamine on functional and morphological changes of liver in the extrahepatic biliary obstruction through an experimental model in rats. METHODS: Seventy Wistar rats were divided into four groups: control (group C fictitious operation, (group FO, submitted to laparotomy with handling of bile ducts, but without hepatic duct ligation, (group EBO submitted to laparotomy and hepatic duct ligation, one of them submitted to supplementation with glutamine 2% (group G. The control group consisted of 6 animals. The animals from groups FO, EBO and G were divided into three groups consisting of 6 animals each, being sacrificed at 7, 14 and 21 days after operation, respectively. Blood samples were collected for biochemical analysis and a fragment of liver tissue was collected from the middle lobe for histological analysis. RESULTS: Both for biochemical analysis (BT, aspartate and alanine aminotransferase AST, ALT and alkaline phosphatase FAL and for histopathological changes (fibrosis, portal inflammation, parenchymal inflammation, hepatocytic changes and duct proliferation, no statistical difference between groups submitted to extrahepatic biliary obstruction (EBO with and without treatment with glutamine (G was observed. CONCLUSION: Glutamine supplementation did not alter the prognosis of liver enzymes and histopathological changes in animals submitted to extrahepatic biliary obstruction.OBJETIVO: Estudar a influência da glutamina em alterações funcionais e morfológicas do fígado na obstrução biliar extra-hepática por meio de um modelo experimental desenvolvido em ratos. MÉTODOS: Setenta ratos Wistar distribuídos em quatro grupos: controle (grupo C; operação fictícia (grupo OF, submetido à laparotomia com manuseio das vias biliares, mas sem ligadura do ducto hepático; (grupo OBE, submetido à laparotomia exploradora e ligadura do ducto hepático, sendo um deles submetido à suplementação com glutamina a

  10. Evaluating the Effectiveness of Traditional and Alternative Principal Preparation Programs

    Science.gov (United States)

    Pannell, Summer; Peltier-Glaze, Bernnell M.; Haynes, Ingrid; Davis, Delilah; Skelton, Carrie

    2015-01-01

    This study sought to determine the effectiveness on increasing student achievement of principals trained in a traditional principal preparation program and those trained in an alternate route principal preparation program within the same Mississippi university. Sixty-six Mississippi principals and assistant principals participated in the study. Of…

  11. Riccati transformations and principal solutions of discrete linear systems

    International Nuclear Information System (INIS)

    Ahlbrandt, C.D.; Hooker, J.W.

    1984-01-01

    Consider a second-order linear matrix difference equation. A definition of principal and anti-principal, or recessive and dominant, solutions of the equation are given and the existence of principal and anti-principal solutions and the essential uniqueness of principal solutions is proven

  12. Principals, Trust, and Cultivating Vibrant Schools

    Directory of Open Access Journals (Sweden)

    Megan Tschannen-Moran

    2015-03-01

    Full Text Available Although principals are ultimately held accountable to student learning in their buildings, the most consistent research results have suggested that their impact on student achievement is largely indirect. Leithwood, Patten, and Jantzi proposed four paths through which this indirect influence would flow, and the purpose of this special issue is to examine in greater depth these mediating variables. Among mediating variables, we assert that trust is key. In this paper, we explore the evidence that points to the role that faculty trust in the principal plays in student learning and how principals can cultivate trust by attending to the five facets of trust, as well as the correlates of trust that mediate student learning, including academic press, collective teacher efficacy, and teacher professionalism. We argue that trust plays a role in each of the four paths identified by Leithwood, Patten, and Jantzi. Finally, we explore possible new directions for future research.

  13. Principal component regression for crop yield estimation

    CERN Document Server

    Suryanarayana, T M V

    2016-01-01

    This book highlights the estimation of crop yield in Central Gujarat, especially with regard to the development of Multiple Regression Models and Principal Component Regression (PCR) models using climatological parameters as independent variables and crop yield as a dependent variable. It subsequently compares the multiple linear regression (MLR) and PCR results, and discusses the significance of PCR for crop yield estimation. In this context, the book also covers Principal Component Analysis (PCA), a statistical procedure used to reduce a number of correlated variables into a smaller number of uncorrelated variables called principal components (PC). This book will be helpful to the students and researchers, starting their works on climate and agriculture, mainly focussing on estimation models. The flow of chapters takes the readers in a smooth path, in understanding climate and weather and impact of climate change, and gradually proceeds towards downscaling techniques and then finally towards development of ...

  14. Application of chaotic ant swarm optimization in electric load forecasting

    International Nuclear Information System (INIS)

    Hong, W.-C.

    2010-01-01

    Support vector regression (SVR) had revealed strong potential in accurate electric load forecasting, particularly by employing effective evolutionary algorithms to determine suitable values of its three parameters. Based on previous research results, however, these employed evolutionary algorithms themselves have several drawbacks, such as converging prematurely, reaching slowly the global optimal solution, and trapping into a local optimum. This investigation presents an SVR-based electric load forecasting model that applied a novel algorithm, namely chaotic ant swarm optimization (CAS), to improve the forecasting performance by searching its suitable parameters combination. The proposed CAS combines with the chaotic behavior of single ant and self-organization behavior of ant colony in the foraging process to overcome premature local optimum. The empirical results indicate that the SVR model with CAS (SVRCAS) results in better forecasting performance than the other alternative methods, namely SVRCPSO (SVR with chaotic PSO), SVRCGA (SVR with chaotic GA), regression model, and ANN model.

  15. Social isolation and brain development in the ant Camponotus floridanus.

    Science.gov (United States)

    Seid, Marc A; Junge, Erich

    2016-06-01

    Social interactions play a key role in the healthy development of social animals and are most pronounced in species with complex social networks. When developing offspring do not receive proper social interaction, they show developmental impairments. This effect is well documented in mammalian species but controversial in social insects. It has been hypothesized that the enlargement of the mushroom bodies, responsible for learning and memory, observed in social insects is needed for maintaining the large social networks and/or task allocation. This study examines the impact of social isolation on the development of mushroom bodies of the ant Camponotus floridanus. Ants raised in isolation were shown to exhibit impairment in the growth of the mushroom bodies as well as behavioral differences when compared to ants raised in social groups. These results indicate that social interaction is necessary for the proper development of C. floridanus mushroom bodies.

  16. Antígonas. Una visión intertextual

    Directory of Open Access Journals (Sweden)

    Elena Cano Turrión

    2011-04-01

    Full Text Available In this article and from an intertextual point of view, we will try to examine how theSophoclean hypotext has generated three very different hypertexts. The first one is the short story“Antígona o la elección” by M. Yourcenar, which goes further the religious motivation in the originaltext; then, there is an essay written as a dialogue by Maria Zambrano, entitled La tumba de Antígonawhich main topics are confrontation against power, lack of freedom and destiny and faith in humanconscience. Finally, Luis Riaza’s Antígona…¡Cerda! Appears closer to its hypotext but at the same timesemantic deviation becomes more relevant.

  17. Effective ANT based Routing Algorithm for Data Replication in MANETs

    Directory of Open Access Journals (Sweden)

    N.J. Nithya Nandhini

    2013-12-01

    Full Text Available In mobile ad hoc network, the nodes often move and keep on change its topology. Data packets can be forwarded from one node to another on demand. To increase the data accessibility data are replicated at nodes and made as sharable to other nodes. Assuming that all mobile host cooperative to share their memory and allow forwarding the data packets. But in reality, all nodes do not share the resources for the benefits of others. These nodes may act selfishly to share memory and to forward the data packets. This paper focuses on selfishness of mobile nodes in replica allocation and routing protocol based on Ant colony algorithm to improve the efficiency. The Ant colony algorithm is used to reduce the overhead in the mobile network, so that it is more efficient to access the data than with other routing protocols. This result shows the efficiency of ant based routing algorithm in the replication allocation.

  18. Mating, hybridisation and introgression in Lasius ants (Hymenoptera: Formicidae)

    DEFF Research Database (Denmark)

    Van der Have, Tom; Pedersen, Jes Søe; Boomsma, Jacobus Jan

    2011-01-01

    Recent reviews have shown that hybridisation among ant species is likely to be more common than previously appreci-ated, but that documented cases of introgression remain rare. After molecular phylogenetic work had shown that Euro-pean Lasius niger (LINNAEUS, 1758) and L. psammophilus SEIFERT, 1992...... (formerly L. alienus (FOERSTER, 1850)) are unlikely to be very closely related, we decided to analyse an old data set confirming the conclusion by PEARSON (1983) that these two ants can indeed form viable hybrids. We show that signatures of introgression can be detected in a Danish site...... sympatrically. This would imply that multiple accessible field sites are available to study the molecular details of hybridisation and in-trogression between two ant species that have variable degrees of sympatry throughout their distributional ranges...

  19. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    DEFF Research Database (Denmark)

    Semenova, Tatyana; Hughes, David Peter; Boomsma, Jacobus Jan

    2011-01-01

    hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results: We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing...... classes. Remarkably, the single symbiont that is shared by species of the crown group of Atta and Acromyrmex leaf-cutting ants mostly showed metalloproteinase activity, suggesting that recurrent changes in enzyme production may have occurred throughout the domestication history of fungus-garden symbionts......Background: Attine ants live in symbiosis with a basidiomycetous fungus that they rear on a substrate of plant material. This indirect herbivory implies that the symbiosis is likely to be nitrogen deprived, so that specific mechanisms may have evolved to enhance protein availability. We therefore...

  20. Comparative Immature Morphology of Brazilian Fire Ants (Hymenoptera: Formicidae: Solenopsis

    Directory of Open Access Journals (Sweden)

    Eduardo Gonçalves Paterson Fox

    2012-01-01

    Full Text Available Although common in Brazil, the biology of the fire ant Solenopsis saevissima (Smith is still poorly studied. Larval descriptions are useful to genus-level ant systematics and sometimes to species-level taxonomy. This study presents a detailed description of juveniles of S. saevissima from Brazil, which were compared with Brazilian specimens of Solenopsis invicta Buren, Solenopsis geminata (Fabricius, and Solenopsis altipunctata Pitts. Different larval instars were separated by diagnostic morphological traits which were confirmed by observing moults. Reproductive larvae could be easily sorted by their distinctive body dimensions and shape. Contrary to previous reports on this species, the larvae of S. saevissima proved to be generally identical to those of S. invicta, while a few specimens resembled those of other close species, such as Solenopsis megergates Trager. Mature larvae thus presented considerable intraspecific variation in some characters recently proposed to aid fire ant species separation (morphology of head hairs.

  1. Social context predicts recognition systems in ant queens

    DEFF Research Database (Denmark)

    Dreier, Stéphanie Agnès Jeanine; d'Ettorre, Patrizia

    2009-01-01

    Recognition of group-members is a key feature of sociality. Ants use chemical communication to discriminate nestmates from intruders, enhancing kin cooperation and preventing parasitism. The recognition code is embedded in their cuticular chemical profile, which typically varies between colonies....... We predicted that ants might be capable of accurate recognition in unusual situations when few individuals interact repeatedly, as new colonies started by two to three queens. Individual recognition would be favoured by selection when queens establish dominance hierarchies, because repeated fights...... for dominance are costly; but it would not evolve in absence of hierarchies. We previously showed that Pachycondyla co-founding queens, which form dominance hierarchies, have accurate individual recognition based on chemical cues. Here, we used the ant Lasius niger to test the null hypothesis that individual...

  2. Natural selection drives the evolution of ant life cycles.

    Science.gov (United States)

    Wilson, Edward O; Nowak, Martin A

    2014-09-02

    The genetic origin of advanced social organization has long been one of the outstanding problems of evolutionary biology. Here we present an analysis of the major steps in ant evolution, based for the first time, to our knowledge, on combined recent advances in paleontology, phylogeny, and the study of contemporary life histories. We provide evidence of the causal forces of natural selection shaping several key phenomena: (i) the relative lateness and rarity in geological time of the emergence of eusociality in ants and other animal phylads; (ii) the prevalence of monogamy at the time of evolutionary origin; and (iii) the female-biased sex allocation observed in many ant species. We argue that a clear understanding of the evolution of social insects can emerge if, in addition to relatedness-based arguments, we take into account key factors of natural history and study how natural selection acts on alleles that modify social behavior.

  3. Native supercolonies of unrelated individuals in the invasive Argentine ant

    DEFF Research Database (Denmark)

    Pedersen, Jes Søe; Krieger, Michael J. B.; Vogel, Valérie

    2006-01-01

    organization is not only a key attribute responsible for the ecological dominance of these ants, but also an evolutionary paradox because relatedness between nestmates is effectively zero. Recently, it has been proposed that, in the Argentine ant, unicoloniality is a derived trait that evolved after its......Kinship among group members has long been recognized as a main factor promoting the evolution of sociality and reproductive altruism, yet some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social...... with related individuals who are aggressive toward members of other colonies, we found that native populations also form supercolonies, and are effectively unicolonial. Moreover, just as in introduced populations, the relatedness between nestmates is not distinguishable from zero in these native range...

  4. Ants at Ton Nga Chang Wildlife Sanctuary, Songkhla

    Directory of Open Access Journals (Sweden)

    Watanasit, S.

    2005-03-01

    Full Text Available The aim of this study was to investigate diversity of ant at Ton Nga Chang Wildlife Sanctuary, Hat Yai, Songkhla. Three line transects (100 m each were randomly set up in 2 types of forest area, disturbed and undisturbed. Hand collecting (HC and leaf litter sampling (LL were applied for ant collection within a time limit of 30 minutes for each method. This study was carried out every month during Febuary 2002- Febuary 2003. The results showed that 206 species were placed under 8 subfamilies: Aenictinae, Cerapachyinae, Dolichoderinae, Formicinae, Leptanillinae, Myrmicinae, Ponerinae and Pseudomyrmecinae. Study sites and collection methods could divide ant species into 2 groups, whereas seasonal change could not distinguish the groups by DCA of multivariate analysis.

  5. Social isolation and brain development in the ant Camponotus floridanus

    Science.gov (United States)

    Seid, Marc A.; Junge, Erich

    2016-06-01

    Social interactions play a key role in the healthy development of social animals and are most pronounced in species with complex social networks. When developing offspring do not receive proper social interaction, they show developmental impairments. This effect is well documented in mammalian species but controversial in social insects. It has been hypothesized that the enlargement of the mushroom bodies, responsible for learning and memory, observed in social insects is needed for maintaining the large social networks and/or task allocation. This study examines the impact of social isolation on the development of mushroom bodies of the ant Camponotus floridanus. Ants raised in isolation were shown to exhibit impairment in the growth of the mushroom bodies as well as behavioral differences when compared to ants raised in social groups. These results indicate that social interaction is necessary for the proper development of C. floridanus mushroom bodies.

  6. Ant colonies prefer infected over uninfected nest sites

    DEFF Research Database (Denmark)

    Pontieri, Luigi; Vojvodic, Svjetlana; Graham, Riley

    2014-01-01

    with sporulating mycelium of the entomopathogenic fungus Metarhizium brunneum (infected nests), nests containing nestmates killed by freezing (uninfected nests), and empty nests. In contrast to the expectation pharaoh ant colonies preferentially (84%) moved into the infected nest when presented with the choice...... the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites...... and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown...

  7. EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS

    DEFF Research Database (Denmark)

    De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G

    2010-01-01

    an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across...... the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens...... are targeted primarily towards partial degradation of plant cell walls, reflecting a plesiomorphic state of non-domesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major...

  8. Empleo del modelo animal en la formación en endoscopia diagnóstica y terapéutica de la vía biliar Animal model training in diagnostic and therapeutic biliary tract endoscopy teaching

    Directory of Open Access Journals (Sweden)

    J. Usón-Gargallo

    2010-09-01

    Full Text Available Objetivo. Mostrar nuestra experiencia en la formación en endoscopia terapéutica de la vía biliar en modelo animal. Materiales y métodos. Esta actividad formativa tiene una duración de 13 horas y comienza iniciando al alumno en las diferencias anatómicas de las especies que se emplean, la porcina y la canina, con respecto a la anatomía humana. Las prácticas consisten en habituar al endoscopista a la visión lateral del duodenoscopio; se realizan en un modelo porcino debido a que es más sencillo atravesar el esfínter pilórico, aunque no suele ser muy adecuado para la canulación de la papila duodenal. Tras superar la primera fase se utiliza el modelo canino, que permite adquirir las habilidades y destrezas propias de esta técnica. La evaluación de los resultados se realiza mediante una encuesta anónima. Resultados. El 76% de los alumnos confirma que ha avanzado mucho con este entrenamiento, un 18% regular y un 6% poco. El 75% considera que, tras realizar esta actividad de formación, se encontraría capacitado para llevar a cabo la técnica en su hospital. El 94% de los alumnos recomendaría esta actividad a sus compañeros. Conclusiones. El empleo del modelo animal en la formación en colangiopancreatografía retrógada endoscópica (CPRE permite la adquisición de habilidades básicas necesarias para la práctica, ya que posibilita la repetición de las maniobras y la tutela continuada. Consideramos que con esta metodología mixta se podría acortar la curva de aprendizaje de la CPRE y disminuiría la iatrogenia en las primeras fases.Aim. To show our experience in training in therapeutic endoscopy of the biliary tract in animal model. Materials and methods. This training activity has duration of 13 hours and starts initiating the trainee in anatomical differences with regard to human anatomy that occur between species that are used, the swine and canine. The practices consist of endoscopist to habituate the lateral view of

  9. Pericarpial nectary-visiting ants do not provide fruit protection against pre-dispersal seed predators regardless of ant species composition and resource availability.

    Directory of Open Access Journals (Sweden)

    Priscila Andre Sanz-Veiga

    Full Text Available Extrafloral nectaries can occur in both vegetative and reproductive plant structures. In many Rubiaceae species in the Brazilian Cerrado, after corolla abscission, the floral nectary continues to secret nectar throughout fruit development originating post-floral pericarpial nectaries which commonly attract many ant species. The occurrence of such nectar secreting structures might be strategic for fruit protection against seed predators, as plants are expected to invest higher on more valuable and vulnerable parts. Here, we performed ant exclusion experiments to investigate whether the interaction with ants mediated by the pericarpial nectaries of Tocoyena formosa affects plant reproductive success by reducing the number of pre-dispersal seed predators. We also assessed whether ant protection was dependent on ant species composition and resource availability. Although most of the plants were visited by large and aggressive ant species, such as Ectatomma tuberculatum and species of the genus Camponotus, ants did not protect fruits against seed predators. Furthermore, the result of the interaction was neither related to ant species composition nor to the availability of resources. We suggest that these results may be related to the nature and behavior of the most important seed predators, like Hemicolpus abdominalis weevil which the exoskeleton toughness prevent it from being predated by most ant species. On the other hand, not explored factors, such as reward quality, local ant abundance, ant colony characteristics and/or the presence of alternative energetic sources could also account for variations in ant frequency, composition, and finally ant protective effects, highlighting the conditionality of facultative plant-ant mutualisms.

  10. Geometry of Quantum Principal Bundles. Pt. 1

    International Nuclear Information System (INIS)

    Durdevic, M.

    1996-01-01

    A theory of principal bundles possessing quantum structure groups and classical base manifolds is presented. Structural analysis of such quantum principal bundles is performed. A differential calculus is constructed, combining differential forms on the base manifold with an appropriate differential calculus on the structure quantum group. Relations between the calculus on the group and the calculus on the bundle are investigated. A concept of (pseudo)tensoriality is formulated. The formalism of connections is developed. In particular, operators of horizontal projection, covariant derivative and curvature are constructed and analyzed. Generalizations of the first Structure Equation and of the Bianchi identity are found. Illustrative examples are presented. (orig.)

  11. Constrained principal component analysis and related techniques

    CERN Document Server

    Takane, Yoshio

    2013-01-01

    In multivariate data analysis, regression techniques predict one set of variables from another while principal component analysis (PCA) finds a subspace of minimal dimensionality that captures the largest variability in the data. How can regression analysis and PCA be combined in a beneficial way? Why and when is it a good idea to combine them? What kind of benefits are we getting from them? Addressing these questions, Constrained Principal Component Analysis and Related Techniques shows how constrained PCA (CPCA) offers a unified framework for these approaches.The book begins with four concre

  12. Agricultural matrices affect ground ant assemblage composition inside forest fragments.

    Directory of Open Access Journals (Sweden)

    Diego Santana Assis

    Full Text Available The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates; sugarcane (3; and pasture (3. At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart. Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

  13. Agricultural matrices affect ground ant assemblage composition inside forest fragments.

    Science.gov (United States)

    Assis, Diego Santana; Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Barrios-Rojas, Katty Elena; Majer, Jonathan David; Vilela, Evaldo Ferreira

    2018-01-01

    The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

  14. Characterization of actinobacteria associated with three ant-plant mutualisms.

    Science.gov (United States)

    Hanshew, Alissa S; McDonald, Bradon R; Díaz Díaz, Carol; Djiéto-Lordon, Champlain; Blatrix, Rumsaïs; Currie, Cameron R

    2015-01-01

    Ant-plant mutualisms are conspicuous and ecologically important components of tropical ecosystems that remain largely unexplored in terms of insect-associated microbial communities. Recent work has revealed that ants in some ant-plant systems cultivate fungi (Chaetothyriales) within their domatia, which are fed to larvae. Using Pseudomyrmex penetrator/Tachigali sp. from French Guiana and Petalomyrmex phylax/Leonardoxa africana and Crematogaster margaritae/Keetia hispida, both from Cameroon, as models, we tested the hypothesis that ant-plant-fungus mutualisms co-occur with culturable Actinobacteria. Using selective media, we isolated 861 putative Actinobacteria from the three systems. All C. margaritae/K. hispida samples had culturable Actinobacteria with a mean of 10.0 colony forming units (CFUs) per sample, while 26 % of P. penetrator/Tachigali samples (mean CFUs 1.3) and 67 % of P. phylax/L. africana samples (mean CFUs 3.6) yielded Actinobacteria. The largest number of CFUs was obtained from P. penetrator workers, P. phylax alates, and C. margaritae pupae. 16S rRNA gene sequencing and phylogenetic analysis revealed the presence of four main clades of Streptomyces and one clade of Nocardioides within these three ant-plant mutualisms. Streptomyces with antifungal properties were isolated from all three systems, suggesting that they could serve as protective symbionts, as found in other insects. In addition, a number of isolates from a clade of Streptomyces associated with P. phylax/L. africana and C. margaritae/K. hispida were capable of degrading cellulose, suggesting that Streptomyces in these systems may serve a nutritional role. Repeated isolation of particular clades of Actinobacteria from two geographically distant locations supports these isolates as residents in ant-plant-fungi niches.

  15. Plant genotype shapes ant-aphid interactions: implications for community structure and indirect plant defense.

    Science.gov (United States)

    Mooney, Kailen A; Agrawal, Anurag A

    2008-06-01

    Little is known about the mechanisms by which plant genotype shapes arthropod community structure. In a field experiment, we measured the effects of milkweed (Asclepias syriaca) genotype and ants on milkweed arthropods. Populations of the ant-tended aphid Aphis asclepiadis and the untended aphid Myzocallis asclepiadis varied eight- to 18-fold among milkweed genotypes, depending on aphid species and whether ants were present. There was no milkweed effect on predatory arthropods. Ants increased Aphis abundance 59%, decreased Myzocallis abundance 52%, and decreased predator abundance 56%. Milkweed genotype indirectly influenced ants via direct effects on Aphis and Myzocallis abundance. Milkweed genotype also modified ant-aphid interactions, influencing the number of ants attracted per Aphis and Myzocallis. While ant effects on Myzocallis were consistently negative, effects on Aphis ranged from antagonistic to mutualistic among milkweed genotypes. As a consequence of milkweed effects on ant-aphid interactions, ant abundance varied 13-fold among milkweed genotypes, and monarch caterpillar survival was negatively correlated with genetic variation in ant abundance. We speculate that heritable variation in milkweed phloem sap drives these effects on aphids, ants, and caterpillars. In summary, milkweed exerts genetic control over the interactions between aphids and an ant that provides defense against foliage-feeding caterpillars.

  16. Intrapopulation differences in ant eating in the mountain gorillas of Bwindi Impenetrable National Park, Uganda.

    Science.gov (United States)

    Ganas, Jessica; Robbins, Martha M

    2004-10-01

    Variability in ant eating has been observed in several populations of eastern and western gorillas. We investigated the occurrence of ant (Dorylus sp.) eating in two groups of mountain gorillas (Gorilla beringei beringei) with overlapping home ranges within Bwindi Impenetrable National Park, Uganda from September 2001 to August 2002. We calculated the frequency of ant eating by an indirect method of analyzing fecal samples from silverbacks, adult females, and juveniles. One group consumed ants significantly more often than the other (3.3 vs 17.6% of days sampled). Furthermore, the group that consumed ants more often also consumed them on a seasonal basis (September-February monthly range: 0-8%; March-August monthly range: 30-42.9%). Finally, females and juveniles of this group consumed ants significantly more often than did the silverback (total samples containing ants: silverback, 2.1%; adult female, 13.2%; juvenile, 11.2%). Differences in ant eating between groups are likely due to variability in use of habitats where ants occur (particularly secondary forests). Surveys of ant densities in differing habitats, nutritional analysis of ants, and quantification of the amount of ants in their diets are necessary to understand if ant consumption is due to availability, nutritional value, group traditions, or taste preference.

  17. Five new records of ants (Hymenoptera: Formicidae) from Morocco.

    Science.gov (United States)

    Taheri, Ahmed; Reyes-López, Joaquin L

    2015-01-01

    A recent catalogue of the rich ant fauna of Morocco included 214 species, with later studies adding an additional 12 species. Following recent fieldwork in the north of Morocco, we report five new records for the country (Plagiolepis pygmaea Latreille, 1798, Ponera testacea Emery, 1895, Strumigenys tenuipilis Emery, 1915, Temnothorax pardoi Tinaut, 1987, and Tetramorium parvioculum Guillem & Bensusan, 2009) and we present new data on the distribution and natural history of six additional species. This work brings the total number of ants known from Morocco to 233, taking into account two species which were omitted in the list of Cagniant. © Crown copyright 2015.

  18. Core Business Selection Based on Ant Colony Clustering Algorithm

    Directory of Open Access Journals (Sweden)

    Yu Lan

    2014-01-01

    Full Text Available Core business is the most important business to the enterprise in diversified business. In this paper, we first introduce the definition and characteristics of the core business and then descript the ant colony clustering algorithm. In order to test the effectiveness of the proposed method, Tianjin Port Logistics Development Co., Ltd. is selected as the research object. Based on the current situation of the development of the company, the core business of the company can be acquired by ant colony clustering algorithm. Thus, the results indicate that the proposed method is an effective way to determine the core business for company.

  19. Significance of chemical recognition cues is context dependent in ants

    DEFF Research Database (Denmark)

    Bos, N.; Guerrieri, F.J.; d'Ettorre, P.

    2010-01-01

    signatures, composed primarily of long-chain cuticular hydrocarbons. These signatures are colony specific and allow discrimination between nestmates and non-nestmates. Nevertheless, the mechanisms underlying detection, perception and information processing of chemical signatures are poorly understood. It has...... context, affects aggression against non-nestmates carrying the hydrocarbon profile associated with food. Individual ant workers were able to associate the non-nestmate chemical profile with food. However, conditioned ants were still aggressive when encountering a non-nestmate carrying the odour profile...

  20. Mutualistic fungi control crop diversity in fungus-growing ants

    DEFF Research Database (Denmark)

    Poulsen, Michael; Boomsma, Jacobus J

    2005-01-01

    Leaf-cutting ants rear clonal fungi for food and transmit the fungi from mother to daughter colonies so that symbiont mixing and conflict, which result from competition between genetically different clones, are avoided. Here we show that despite millions of years of predominantly vertical...... transmission, the domesticated fungi actively reject mycelial fragments from neighboring colonies, and that the strength of these reactions are in proportion to the overall genetic difference between these symbionts. Fungal incompatibility compounds remain intact during ant digestion, so that fecal droplets...

  1. Are queen ants inhibited by their own pheromone?

    DEFF Research Database (Denmark)

    Holman, L.; Leroy, C.; Jørgensen, Charlotte

    2013-01-01

    . Communication in social insects is predominantly chemical, and the mechanisms regulating processes such as reproductive division of labor are becoming increasingly well understood. Recently, a queen cuticular hydrocarbon (3-MeC31) that inhibits worker reproduction and aggression was isolated in the ant Lasius...... niger. Here, we find that this pheromone also has a weak negative effect on queen productivity and oogenesis. Because 3-MeC31 is present on both queens and their brood, we suggest that it is used by ants of both castes to adjust their fecundity to the amount of developing brood and the presence of other...

  2. Sperm storage induces an immunity cost in ants

    DEFF Research Database (Denmark)

    Baer, Boris; Armitage, Sophie A O; Boomsma, Jacobus J

    2006-01-01

    Ant queens are among the most long-lived insects known. They mate early in adult life and maintain millions of viable sperm in their sperm storage organ until they die many years later. Because they never re-mate, the reproductive success of queens is ultimately sperm-limited, but it is not known...... what selective forces determine the upper limit to sperm storage. Here we show that sperm storage carries a significant cost of reduced immunity during colony founding. Newly mated queens of the leaf-cutting ant Atta colombica upregulate their immune response shortly after completing their nest burrow...

  3. The search rate of the African weaver ant in cashew

    DEFF Research Database (Denmark)

    Henriksen, Signe; Axelsen, Jørgen Aagaard; Lemming, Katrine Hansen

    2015-01-01

    Oecophylla longinoda is a species of eusocial colony living ants that prey upon other insects to feed their larva. Many of these insects are considered pests. An ecosystem model of the interactions between an O. longinoda colony and its potential prey is under construction by the team behind...... this article, and it is unknown which functional response equations are useful for eusocial insect colonies. We investigated the search rate of O. longinoda using artificial feeding experiments in a Tanzanian cashew (Anacardium occidentale L.) orchard to determine the search efficiency of the ants...

  4. Application of ant colony optimization in NPP classification fault location

    International Nuclear Information System (INIS)

    Xie Chunli; Liu Yongkuo; Xia Hong

    2009-01-01

    Nuclear Power Plant is a highly complex structural system with high safety requirements. Fault location appears to be particularly important to enhance its safety. Ant Colony Optimization is a new type of optimization algorithm, which is used in the fault location and classification of nuclear power plants in this paper. Taking the main coolant system of the first loop as the study object, using VB6.0 programming technology, the NPP fault location system is designed, and is tested against the related data in the literature. Test results show that the ant colony optimization can be used in the accurate classification fault location in the nuclear power plants. (authors)

  5. Sex-specific kleptoparasitic foraging in ant-eating spiders

    DEFF Research Database (Denmark)

    Martisová, Martina; Bilde, T.; Pekar, Stano

    2009-01-01

    . To investigate this hypothesis, we studied the effect of sex and life history stage on the frequency of kleptoparasitism in ant-eating spiders of the genus Zodarion in the field. These spiders use a special capture technique involving a quick attack on an ant that is left unguarded by spiders for several minutes......, providing ample opportunities for kleptoparasitism. We found that adult females consistently hunted actively, while adult males ceased active prey capture and instead engaged in kleptoparasitism. Juvenile spiders were active hunters irrespective of sex. Consistent with an ontogenetic shift in foraging...

  6. The Deputy Principal Instructional Leadership Role and Professional Learning: Perceptions of Secondary Principals, Deputies and Teachers

    Science.gov (United States)

    Leaf, Ann; Odhiambo, George

    2017-01-01

    Purpose: The purpose of this paper is to report on a study examining the perceptions of secondary principals, deputies and teachers, of deputy principal (DP) instructional leadership (IL), as well as deputies' professional learning (PL) needs. Framed within an interpretivist approach, the specific objectives of this study were: to explore the…

  7. Statewide Data on Supply and Demand of Principals after Policy Changes to Principal Preparation in Illinois

    Science.gov (United States)

    Haller, Alicia; Hunt, Erika

    2016-01-01

    Research has demonstrated that principals have a powerful impact on school improvement and student learning. Principals play a vital role in recruiting, developing, and retaining effective teachers; creating a school-wide culture of learning; and implementing a continuous improvement plan aimed at increasing student achievement. Leithwood, Louis,…

  8. Principal Self-Efficacy, Teacher Perceptions of Principal Performance, and Teacher Job Satisfaction

    Science.gov (United States)

    Evans, Molly Lynn

    2016-01-01

    In public schools, the principal's role is of paramount importance in influencing teachers to excel and to keep their job satisfaction high. The self-efficacy of leaders is an important characteristic of leadership, but this issue has not been extensively explored in school principals. Using internet-based questionnaires, this study obtained…

  9. Andragogical Practices of School Principals in Developing the Leadership Capacities of Assistant Principals

    Science.gov (United States)

    McDaniel, Luther

    2017-01-01

    The purpose of this mixed methods study was to assess school principals' perspectives of the extent to which they apply the principles of andragogy to the professional development of assistant principals in their schools. This study was conducted in school districts that constitute a RESA area in a southeastern state. The schools in these…

  10. Conflict over reproduction in an ant-plant symbiosis: why Allomerus octoarticulatus ants sterilize Cordia nodosa trees.

    Science.gov (United States)

    Frederickson, Megan E

    2009-05-01

    The evolutionary stability of mutualism is thought to depend on how well the fitness interests of partners are aligned. Because most ant-myrmecophyte mutualisms are persistent and horizontally transmitted, partners share an interest in growth but not in reproduction. Resources invested in reproduction are unavailable for growth, giving rise to a conflict of interest between partners. I investigated whether this explains why Allomerus octoarticulatus ants sterilize Cordia nodosa trees. Allomerus octoarticulatus nests in the hollow stem domatia of C. nodosa. Workers protect C. nodosa leaves against herbivores but destroy inflorescences. Using C. nodosa trees with Azteca ants, which do not sterilize their hosts, I cut inflorescences off trees to simulate sterilization by A. octoarticulatus. Sterilized C. nodosa grew faster than control trees, providing evidence for a trade-off between growth and reproduction. Allomerus octoarticulatus manipulates this trade-off to its advantage; sterilized trees produce more domatia and can house larger, more fecund colonies.

  11. EL SECRETO PROFESIONAL ANTE EL NOTARIO

    Directory of Open Access Journals (Sweden)

    Ignacio Vidal Domínguez

    2002-01-01

    Full Text Available Nuestra legislación en general se encuentra inspirada en el principio de la publicidad registral. Por lo mismo llama la atención que en lo notarial pueda existir algo "secreto". No existe en los protocolos a cargo de los notarios nada que sea privado. Lo mismo ocurre con respecto a los registros y libros a cargo de conservadores y archiveros judiciales. Sin embargo no es tan así de simple. Las líneas que siguen pretenden dar algunas luces sobre el tema, casi no tratado hasta ahora, al menos en nuestra doctrina, no así en la extranjera. El tema en absoluto está agotado. Nuestra pretensión es entregar los primeros esbozos para un estudio más acabado.In general, our legislation is based on the principals of registering publicity. Therefore, it calls our attention the fact that there can be something "secret" in the notarial. There does not exist anything that is private in the protocol in charge of the notaries. It is the same with records and books, which the legal preservers and file clerks are in charge of. However, it is not that simple. The guidelines they follow try to give some light on this subject, which has hardly been dealt with until now, at least in our area, although it has been touched abroad. The subject has not run out. We intend to give the first outlines for a more profound study.

  12. What Principals Should Know About Food Allergies.

    Science.gov (United States)

    Munoz-Furlong, Anne

    2002-01-01

    Describes what principals should know about recent research findings on food allergies (peanuts, tree nuts, milk, eggs, soy, wheat) that can produce severe or life-threatening reactions in children. Asserts that every school should have trained staff and written procedures for reacting quickly to allergic reactions. (PKP)

  13. A Principal's Guide to Children's Allergies.

    Science.gov (United States)

    Munoz-Furlong, Anne

    1999-01-01

    Discusses several common children's allergies, including allergic rhinitis, asthma, atopic dermatitis, food allergies, and anaphylactic shock. Principals should become familiar with various medications and should work with children's parents and physicians to determine how to manage their allergies at school. Allergen avoidance is the best…

  14. Assessment of School Principals' Reassignment Process

    Science.gov (United States)

    Sezgin-Nartgün, Senay; Ekinci, Serkan

    2016-01-01

    This study aimed to identify administrators' views related to the assessment of school principals' reassignment in educational organizations. The study utilized qualitative research design and the study group composed of 8 school administrators selected via simple sampling who were employed in the Bolu central district in 2014-2015 academic year.…

  15. An Exploration of Principal Instructional Technology Leadership

    Science.gov (United States)

    Townsend, LaTricia Walker

    2013-01-01

    Nationwide the demand for schools to incorporate technology into their educational programs is great. In response, North Carolina developed the IMPACT model in 2003 to provide a comprehensive model for technology integration in the state. The model is aligned to national educational technology standards for teachers, students, and principals.…

  16. Principals' Leadership Styles and Student Achievement

    Science.gov (United States)

    Harnish, David Alan

    2012-01-01

    Many schools struggle to meet No Child Left Behind's stringent adequate yearly progress standards, although the benchmark has stimulated national creativity and reform. The purpose of this study was to explore teacher perceptions of principals' leadership styles, curriculum reform, and student achievement to ascertain possible factors to improve…

  17. How To Select a Good Assistant Principal.

    Science.gov (United States)

    Holman, Linda J.

    1997-01-01

    Notes that a well-structured job profile and interview can provide insight into the key qualities of an effective assistant principal. These include organizational skills, basic accounting knowledge, interpersonal skills, dependability, strong work ethic, effective problem-solving skills, leadership skills, written communication skills,…

  18. Principals' Transformational Leadership in School Improvement

    Science.gov (United States)

    Yang, Yingxiu

    2013-01-01

    Purpose: This paper aims to contribute experience and ideas of the transformational leadership, not only for the principal want to improve leadership himself (herself), but also for the school at critical period of improvement, through summarizing forming process and the problem during the course and key factors that affect the course.…

  19. Imprecise Beliefs in a Principal Agent Model

    NARCIS (Netherlands)

    Rigotti, L.

    1998-01-01

    This paper presents a principal-agent model where the agent has multiple, or imprecise, beliefs. We model this situation formally by assuming the agent's preferences are incomplete. One can interpret this multiplicity as an agent's limited knowledge of the surrounding environment. In this setting,

  20. Bootstrap confidence intervals for principal response curves

    NARCIS (Netherlands)

    Timmerman, Marieke E.; Ter Braak, Cajo J. F.

    2008-01-01

    The principal response curve (PRC) model is of use to analyse multivariate data resulting from experiments involving repeated sampling in time. The time-dependent treatment effects are represented by PRCs, which are functional in nature. The sample PRCs can be estimated using a raw approach, or the

  1. Bootstrap Confidence Intervals for Principal Response Curves

    NARCIS (Netherlands)

    Timmerman, M.E.; Braak, ter C.J.F.

    2008-01-01

    The principal response curve (PRC) model is of use to analyse multivariate data resulting from experiments involving repeated sampling in time. The time-dependent treatment effects are represented by PRCs, which are functional in nature. The sample PRCs can be estimated using a raw approach, or the

  2. Islamitisch financieren tussen principes en realiteit

    NARCIS (Netherlands)

    Wolters, W.G.

    2009-01-01

    ‘De financiële crisis zou niet hebben plaatsgevonden, als de wereld de principes van islamitisch bankieren en financieren zou hebben aangenomen.’ Dat was één van de kenmerkende reacties van de kant van de islamitische bankiers, in de laatste maanden van 2008. Toen begon de wereldwijde financiële

  3. Dealing with Crises: One Principal's Experience.

    Science.gov (United States)

    Foley, Charles F.

    1986-01-01

    The principal of Concord High School (New Hampshire) recounts the 1985-86 school year's four crises--the visits of teacher-astronaut Christa McAuliffe and Secretary of Education William Bennett, the shooting of a former student, and the Challenger space shuttle explosion. The greatest challenge was resuming the normal schedule and fielding media…

  4. Principal Pressure in the Middle of Accountability

    Science.gov (United States)

    Derrington, Mary Lynne; Larsen, Donald E.

    2012-01-01

    When a new superintendent is hired, Tom Thompson, middle school principal, is squeezed between complying with the demands of the district and cultivating a positive culture in his school. He wrestles with the stress of facing tough leadership choices that take a toll on his physical and mental health. Tom realizes that a career-ending move might…

  5. The Relationship between Principals' Managerial Approaches and ...

    African Journals Online (AJOL)

    Students' discipline is critical to the attainment of positive school outcomes. This paper presents and discusses findings of a study on the relationship between principals' management approaches and the level of student discipline in selected public secondary schools in Kenya. The premise of the study was that the level of ...

  6. Primary School Principals' Experiences with Smartphone Apps

    Science.gov (United States)

    Çakir, Rahman; Aktay, Sayim

    2016-01-01

    Smartphones are not just pieces of hardware, they at same time also dip into software features such as communication systems. The aim of this study is to examine primary school principals' experiences with smart phone applications. Shedding light on this subject means that this research is qualitative. Criterion sampling has been intentionally…

  7. Principal normal indicatrices of closed space curves

    DEFF Research Database (Denmark)

    Røgen, Peter

    1999-01-01

    A theorem due to J. Weiner, which is also proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with nonvanishing curvature has integrated geodesic curvature zero and contains no subarc with integrated geodesic curvature pi. We prove that the inverse problem alw...

  8. Summer Principals'/Directors' Orientation Training Module.

    Science.gov (United States)

    Mata, Robert L.; Garcia, Richard L.

    Intended to provide current or potential project principals/directors with the basic knowledge, skills, abilities, and sensitivities needed to manage a summer migrant school project in the local educational setting, this module provides instruction in the project management areas of planning, preparation, control, and termination. The module…

  9. Probabilistic Principal Component Analysis for Metabolomic Data.

    LENUS (Irish Health Repository)

    Nyamundanda, Gift

    2010-11-23

    Abstract Background Data from metabolomic studies are typically complex and high-dimensional. Principal component analysis (PCA) is currently the most widely used statistical technique for analyzing metabolomic data. However, PCA is limited by the fact that it is not based on a statistical model. Results Here, probabilistic principal component analysis (PPCA) which addresses some of the limitations of PCA, is reviewed and extended. A novel extension of PPCA, called probabilistic principal component and covariates analysis (PPCCA), is introduced which provides a flexible approach to jointly model metabolomic data and additional covariate information. The use of a mixture of PPCA models for discovering the number of inherent groups in metabolomic data is demonstrated. The jackknife technique is employed to construct confidence intervals for estimated model parameters throughout. The optimal number of principal components is determined through the use of the Bayesian Information Criterion model selection tool, which is modified to address the high dimensionality of the data. Conclusions The methods presented are illustrated through an application to metabolomic data sets. Jointly modeling metabolomic data and covariates was successfully achieved and has the potential to provide deeper insight to the underlying data structure. Examination of confidence intervals for the model parameters, such as loadings, allows for principled and clear interpretation of the underlying data structure. A software package called MetabolAnalyze, freely available through the R statistical software, has been developed to facilitate implementation of the presented methods in the metabolomics field.

  10. Principals in Partnership with Math Coaches

    Science.gov (United States)

    Grant, Catherine Miles; Davenport, Linda Ruiz

    2009-01-01

    One of the most promising developments in math education is the fact that many districts are hiring math coaches--also called math resource teachers, math facilitators, math lead teachers, or math specialists--to assist elementary-level teachers with math instruction. What must not be lost, however, is that principals play an essential role in…

  11. Experimental and principal component analysis of waste ...

    African Journals Online (AJOL)

    The present study is aimed at determining through principal component analysis the most important variables affecting bacterial degradation in ponds. Data were collected from literature. In addition, samples were also collected from the waste stabilization ponds at the University of Nigeria, Nsukka and analyzed to ...

  12. Principal Component Analysis as an Efficient Performance ...

    African Journals Online (AJOL)

    This paper uses the principal component analysis (PCA) to examine the possibility of using few explanatory variables (X's) to explain the variation in Y. It applied PCA to assess the performance of students in Abia State Polytechnic, Aba, Nigeria. This was done by estimating the coefficients of eight explanatory variables in a ...

  13. Principal component analysis of psoriasis lesions images

    DEFF Research Database (Denmark)

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær

    2003-01-01

    A set of RGB images of psoriasis lesions is used. By visual examination of these images, there seem to be no common pattern that could be used to find and align the lesions within and between sessions. It is expected that the principal components of the original images could be useful during future...

  14. The Principal as Professional Development Leader

    Science.gov (United States)

    Lindstrom, Phyllis H.; Speck, Marsha

    2004-01-01

    Individual teachers have the greatest effect on student performance. Principals, as professional development leaders, are in the best position to provide teachers with the professional development strategies they need to improve skills and raise student achievement. This book guides readers through a step-by-step process to formulate, implement,…

  15. Burnout And Lifestyle Of Principals And Entrepreneurs

    Directory of Open Access Journals (Sweden)

    Jasna Lavrenčič

    2014-12-01

    Full Text Available Research Question (RQ: What kind of lifestyle do the principals and entrepreneurs lead? Does the lifestyle of principals and entrepreneurs influence burnout? Purpose: To find out, based on the results of a questionnaire, what kind of lifestyle both researched groups lead. Does lifestyle have an influence on the occurrence of the phenomenon of burnout. Method: We used the method of data collection by questionnaire. Acquired data were analyzed using SPSS, descriptive and inference statistics. Results: Results showed, that both groups lead a similar lifestyle and that lifestyle influences burnout with principals, as well as entrepreneurs. Organization: School principals and entrepreneurs are the heads of individual organizations or companies, the goal of which is success. To be successful in their work, they must adapt their lifestyle, which can be healthy or unhealthy. If their lifestyle is unhealthy, it can lead to burnout. Society: With results of the questionnaire we would like to answer the question about the lifestyle of both groups and its influence on the occurrence of burnout. Originality: The study of lifestyle and the occurrence of burnout in these two groups is the first study in this area. Limitations/Future Research: In continuation, research groups could be submitted to the research fields of effort physiology and tracking of certain haematological parameters, such as cholesterol, blood sugar and stress hormones - adrenaline, noradrenalin, cortisol. Thus, we could carry out an even more in depth research of the connection between lifestyle and burnout.

  16. Principal Connection / Amazon and the Whole Teacher

    Science.gov (United States)

    Hoerr, Thomas R.

    2015-01-01

    A recent controversy over Amazon's culture has strong implications for the whole child approach, and it offers powerful lessons for principals. A significant difference between the culture of so many businesses today and the culture at good schools is that in good schools, the welfare of the employees is very important. Student success is the…

  17. The Gender of Secondary School Principals.

    Science.gov (United States)

    Bonuso, Carl; Shakeshaft, Charol

    1983-01-01

    A study was conducted to understand why so few of the secondary school principals in New York State are women. Results suggest two possible causes: either sufficient women candidates do not apply for the positions, or sex discrimination still exists. (KH)

  18. A pest is a pest is a pest? The dilemma of neotropical leaf-cutting ants: Keystone taxa of natural ecosystems

    Science.gov (United States)

    Fowler, Harold G.; Pagani, Maria Inez; da Silva, Osvaldo Aulino; Forti, Luis Carlos; da Silva, Virgilio Pereira; de Vasconcelos, Heraldo Luis

    1989-11-01

    Leaf-cutting ants of the genera Acromyrmex and Atta are considered the principal polyphagous pests of the Neotropics Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests of Atta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems Likewise, the pest species can be used to detect environmental disturbance As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs

  19. The genomic impact of 100 million years of social evolution in seven ant species

    DEFF Research Database (Denmark)

    Gadau, Jürgen; Helmkampf, Martin; Nygaard, Sanne

    2012-01-01

    Ants (Hymenoptera, Formicidae) represent one of the most successful eusocial taxa in terms of both their geographic distribution and species number. The publication of seven ant genomes within the past year was a quantum leap for socio- and ant genomics. The diversity of social organization in ants...... between social and solitary insects, as well as among ant species. Altogether, these seven ant genomes open exciting new research avenues and opportunities for understanding the genetic basis and regulation of social species, and adaptive complex systems in general....... makes them excellent model organisms to study the evolution of social systems. Comparing the ant genomes with those of the honeybee, a lineage that evolved eusociality independently from ants, and solitary insects suggests that there are significant differences in key aspects of genome organization...

  20. Impact of imidacloprid on new queens of imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae)

    Science.gov (United States)

    Neonicotinoid insecticides are commonly used in managing pest ants, including the imported fire ant, Solenopsis invicta Buren. There is increasing evidence that neonicotinoid insecticides at sublethal concentrations have profound effects on social insects. However, the sublethal effect of neonicot...