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Search Results: 1 - 10 of 93288 matches for " Roberto da Silva;Forti "
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Nest Digging by Leaf-Cutting Ants: Effect of Group Size and Functional Structures
Roberto da Silva Camargo,Ricardo Toshio Fujihara,Luiz Carlos Forti
Psyche , 2012, DOI: 10.1155/2012/426719
Abstract: Leaf-cutting ant workers dig underground chambers, for housing their symbiotic fungus, interconnected by a vast quantity of tunnels whose function is to permit the entrance of food (leaves), gaseous exchanges, and movement of workers, offspring, and the queen. Digging is a task executed by a group of workers, but little is known about the group effect and group-constructed functional structures. Thus, we analyzed the structures formed by worker groups (5, 10, 20, and 40 individuals) of the leaf-cutting ant, Atta sexdens rubropilosa, for 2 days of excavation. The digging arena was the same for the 4 groups, with each group corresponding to a different density. Our results verified a pattern of tunneling by the workers, but no chamber was constructed. The group effect is well known, since the 40-worker group dug significantly more than the groups of 5, 10, and 20. These groups did not differ statistically from each other. Analysis of load/worker verified that workers of the smallest group carried the greatest load. Our paper demonstrates the group effect on the digging of nests, namely, that excavation is proportional to group size, but without emergence of a functional structure such as a chamber.
Lipid and energy contents in the bodies of queens of Atta sexdens rubropilosa Forel (Hymenoptera, Formicidae): pre-and post-nuptial flight
Fujihara, Ricardo Toshio;Camargo, Roberto da Silva;Forti, Luiz Carlos;
Revista Brasileira de Entomologia , 2012, DOI: 10.1590/S0085-56262012005000015
Abstract: the nuptial flight allows males and females to meet and copulate and both need energy to perform this activity. before leaving the nest, males and females are well nourished and ready to mate. however, little is known about the lipid and energy contents in females before the nuptial flight (virgins) and after it (mated females). in this work we measured lipid concentrations in relation to body weight in these individuals. our results showed that 16.82% of the bodies of young virgin females one month before mating flight are composed of lipids, contrasting with the 32.62% lipid content in mated females who had not excavated their nest yet, and 32.88% in those who had. the energy content measured for virgin females was 2942.63 j, contrasting with 6110.01 j for queens before excavating the nest and 5677.51 j after excavation. based on our results, we conclude that the body mass, and therefore the lipid and energy contents in the bodies of atta sexdens rubropilosa queens double during the last month before the nuptial flight. this energy resource is fundamental to the activities required during the nuptial flight, digging the nest and the founding of the colony.
Predatory Behavior of Canthon virens (Coleoptera: Scarabaeidae): A Predator of Leafcutter Ants
Luiz Carlos Forti,Isabela Maria Piovesan Rinaldi,Roberto da Silva Camargo,Ricardo Toshio Fujihara
Psyche , 2012, DOI: 10.1155/2012/921465
Abstract: We present a detailed description of the predatory behavior of the beetle Canthon virens Mannerheim, 1829, on the leafcutter ant Atta sp. We observed 51 acts of predation, which were also recorded on film and subjected to behavioral analysis. Canthon virens exhibited 28 behaviors while predating upon Atta sp. queens. Adult beetles search for queens while flying in a zigzag pattern, 15 to 20 cm above the ground. After catching a queen, the predator stands on its back and starts cutting the queen cervix. Once the prey is decapitated, the predator rolls it until an insurmountable obstacle is reached. The distance from the site of predation to the obstacle can vary widely and is unpredictable. The beetle rolling the queen also buries it in a very peculiar way: first, it digs a small hole and pulls the queen inside, while another beetle is attached to the prey. The burial process takes many hours (up to 12) and may depend on the hardness of the soil and the presence of obstacles. In general, one or two beetles are found in a chamber with the queen after it is buried. They make the brood balls, which serve as food for the offspring. This study contributes to the knowledge of the predatory behavior of Canthon virens, a predator poorly studied in Brazil and widespread in the country.
Characterization of Acromyrmex subterraneus brunneus (Hymenoptera: Formicidae) young nests in a fragment of the Neotropical Forest
Camargo, Roberto da Silva;Forti, Luiz Carlos;Lopes, Juliane Floriano;Andrade, Ana Paula Protti de;
Revista árvore , 2004, DOI: 10.1590/S0100-67622004000200017
Abstract: young nests of acromyrmex subterraneus brunneus are characterized by refuse soil in the exterior of the nest, a single fungus chamber 11 to 20 cm deep in relation to soil surface and internal volume ranging from 0.3 to 1.5 liters. these nidification patterns are important characteristics for identifying and understanding the interactions between species and their habitats.
Avalia o de duas interven es educativas para a preven o do Diabetes Mellitus tipo 2 em adolescentes
Ana Roberta Vilarouca da Silva,Maria Lúcia Zanetti,Adriana Costa e Forti,Roberto Wagner Júnior Freire de Freitas
Texto & Contexto - Enfermagem , 2011,
Abstract: El estudio tuvo como objetivo evaluar dos intervenciones educativas para la prevención de la Diabetes Mellitus tipo 2 en adolescentes en riesgo. Participaron del estudio noventa estudiantes de una escuela pública en la ciudad de Fortaleza, Ceará, Brasil, divididos en dos grupos: GA (n=45) y GB (n=45). El grupo GA recibió una intervención educativa individual, por medio de un folleto, y el grupo GB, una intervención educativa en grupo que comprendió cinco sesiones de dos horas cada una. Se utilizaron cuestionarios para evaluar el nivel de conocimientos antes, al día siguiente, y 60 días después de las intervenciones; y los cambios en los hábitos diarios 60 días después del uso de las intervenciones. Los resultados mostraron que para el nivel de conocimientos, las dos intervenciones realizadas no mostraron diferencias (p=0, 0001). Al comparar los grupos A y B después de las intervenciones se observó que la intención de cambiar los hábitos diarios fue similar. Las dos intervenciones educativas pueden ser utilizadas en las escuelas para la prevención de la Diabetes Mellitus tipo 2 en adolescentes en riesgo.
Avalia??o de duas interven??es educativas para a preven??o do Diabetes Mellitus tipo 2 em adolescentes
Silva, Ana Roberta Vilarouca da;Zanetti, Maria Lúcia;Forti, Adriana Costa e;Freitas, Roberto Wagner Júnior Freire de;Hissa, Miguel Nasser;Damasceno, Marta Maria Coelho;
Texto & Contexto - Enfermagem , 2011, DOI: 10.1590/S0104-07072011000400018
Abstract: this study aimed to evaluate two educational interventions to prevent type 2 diabetes mellitus among at-risk adolescents. participants were 90 students from a public school in the city of fortaleza, ceará, brazil, divided into two groups: ga (n=45), and gb (n=45). in the ga group, a flyer was used to individually explain the educational group interventions, while the gb group received educational intervention through five meetings of two hours each. questionnaires were used to evaluate the level of knowledge before, the day after, and 60 days after interventions as well as changes in daily habits, 60 days after interventions. results showed no difference between both interventions (p=0.0001) considering the level of knowledge. a similar intention to change daily habits was observed upon comparing groups a and b after the interventions. the two educational interventions can be used in schools in order to prevent type 2 diabetes mellitus in at-risk adolescents.
Automa??o de projeto e análise de torres metálicas utilizando perfis tubulares
Requena, Jo?o Alberto Venegas;Forti, Tiago Luís Duarte;Forti, Nadia Cazarim da Silva;Araújo, Afonso Henrique M.;
Rem: Revista Escola de Minas , 2007, DOI: 10.1590/S0370-44672007000200025
Abstract: in the present work, introduced is a software (autotorre 1.01) to design steel telecommunication towers using hollow sections. the main purpose of the software is to help and assist the engineer in the process of analyzing and designing a steel tower. the software uses brazilian specifications to compute wind loads and design beams. the calculation of wind loads, structure efforts and beam design is mechanical work that has now been automated and thus saves time for the engineer and allows for focus on other important aspects. software routines allow the user to generate automatically the tower geometry, compute wind load and design the beams. another functionality consists in a modal analysis to obtain the fundamental period of vibration. the software has a friendly graphical user interface. wind load results according to two methods (static and dynamic methods) proposed by the nbr6123 are compared, to obtain a safe and economic structure.
Predi??o da configura??o de sombras de árvores em pastagens para bovinos
Silva, Roberto G. da;
Engenharia Agrícola , 2006, DOI: 10.1590/S0100-69162006000100029
Abstract: equations to estimate orientation, length and surface area of shades projected by trees in cattle feedlots are presented, considering location, year season, and time of the day. the equations refer to six types of tree canopy shape: spherical, lentil-like, cylindrical, ellipsoid, cone, and inverted cone. a worked example is given and discussed.
The public good game on graphs: can the pro-social behavior persist?
Silva, Roberto da;
Brazilian Journal of Physics , 2008, DOI: 10.1590/S0103-97332008000100015
Abstract: this communication proposes new alternatives to study the pro-social behavior in artificial society of players in the context of public good game via monte carlo simulations. here, the pro-social aspect is governed by a binary variable called motivation that incites the player to invest in the public good. this variable is updated according to the benefit achieved by the player, which is quantified by a return function. in this manuscript we propose a new return function in comparison with other one explored by the same author in previous contributions. we analyze the game considering different networks studying noise effects on the density of motivation. estimates of pro-sociability survival probability were obtained as function of randomness (p) in small world networks. we also introduced a new dynamics based on gibbs sampling for which the motivation of a player (now a q-state variable) is chosen according to the return of its neighbors, discarding the negative returns.
Assurance Services: principais conceitos
Silva, Paulo Roberto da;
Caderno de Estudos , 2000, DOI: 10.1590/S1413-92512000000100003
Abstract: o presente artigo pretende divulgar no brasil os estudos desenvolvidos pelo american institute of certified public accountants - aicpa sobre os chamados assurance services (as). essa entidade tem envidado esfor?os para reposicionar a profiss?o num lugar de destaque social. a expectativa é que os as formem os alicerces da próxima evolu??o da área contábil. destacamos o estudo que fornece um esbo?o de estrutura conceitual para os as. seu conteúdo inclui a defini??o, o escopo, alguns requisitos (independência, julgamento profissional, usuários, etc.) e a distin??o entre os vários tipos de servi?os prestados pelos profissionais. entendemos que essa n?o é uma tarefa trivial, devido às diferen?as culturais existentes entre os eua e o brasil. observamos que os as se caracterizam pelo aperfei?oamento da informa??o e/ou seu contexto através da verifica??o independente. embora compreenda servi?os tradicionais (auditoria independente de demonstra??es contábeis), destacamos os servi?os menos estruturados e circunscritos às situa??es específicas (foco no consumidor - usuário). a exigência de independência e do julgamento profissional sugere que a existência de três partes envolvidas (o profissional, os envolvidos com o objeto da informa??o alvo do servi?o e o usuário) é indispensável, mesmo que duas delas perten?am a uma mesma entidade. dentre todos os aspectos positivos relacionados com a divulga??o dos estudos sobre os as no brasil, atribuímos maior importancia ao potencial de alargar os horizontes dos profissionais brasileiros. a "sintonia fina" entre a percep??o do profissional e as efetivas demandas de servi?os pelos usuários contribuiria sobremaneira para a valoriza??o da contabilidade brasileira, trazendo benefícios para toda a sociedade.
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