55 research outputs found

    Ontology of multi-agents processes of spatial decision

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    In the paper of Cavezzali, Girotti and Rabino presented at ERSA 2003 conference, features of multi-agent models and their potentiality for the study of territorial phenomena are discussed. Starting from this study, the present paper digs deeper mechanisms of multi-agent systems working, describing their ontology in a more complete and articulated way as possible, and investigating: the properties of the actors, the mechanisms of interaction among actors and between actors and environment. About the environment, particular attention has been paid to the consideration about the various modalities of treatment of territory (from pure physical support to active reactive/cognitive agent in relationship with the other agents). For these modalities, finally, two typical case-studies of multi-agent model are shown: simulation of pedestrian paths choice, the software “Turisti”, and a competitive dynamic of service centres location, “Wilson”.

    Multi-Agents Systems and Territory: Concepts, Methods and Applications

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    This paper analyses the multi-agents systems that are now considered the best tool to simulate and study real world. We review the main characteristics of a multi-agents system, namely interactions and cooperations of agents, communications and behaviours between them and finally the schedule of actions and jobs assignment to agents. The multi-agents system approach is increasingly applied in social and economic sciences; so we study mainly the territorial applications. In these applications new characteristics arise from the consideration of territory (land and space where the agents live or territory as an agent in itself, that evolves in the time). We study possible new applications of multi-agents applied to the territory (for instance, to define town planning policies or to locate dangerous facilities). Furthermore we study new tools to make operational multi-agents systems (mainly Swarm, the toolkit of Santa Fe Institute). With Swarm we present two kind of territorial applications: with located agents (fixed in space) and with not located agents (moving in the space). Finally we show the results of these applications.

    Biological Control of the Chagas Disease Vector Triatoma infestans with the Entomopathogenic Fungus Beauveria bassiana Combined with an Aggregation Cue: Field, Laboratory and Mathematical Modeling Assessment

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    Background: Current Chagas disease vector control strategies, based on chemical insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant Triatoma infestans populations in the Gran Chaco region of South America. Methodology and findings: We have already shown that the entomopathogenic fungus Beauveria bassiana has the ability to breach the insect cuticle and is effective both against pyrethroid-susceptible and pyrethroid-resistant T. infestans, in laboratory as well as field assays. It is also known that T. infestans cuticle lipids play a major role as contact aggregation pheromones. We estimated the effectiveness of pheromonebased infection boxes containing B. bassiana spores to kill indoor bugs, and its effect on the vector population dynamics. Laboratory assays were performed to estimate the effect of fungal infection on female reproductive parameters. The effect of insect exuviae as an aggregation signal in the performance of the infection boxes was estimated both in the laboratory and in the field. We developed a stage-specific matrix model of T. infestans to describe the fungal infection effects on insect population dynamics, and to analyze the performance of the biopesticide device in vector biological control. Conclusions: The pheromone-containing infective box is a promising new tool against indoor populations of this Chagas disease vector, with the number of boxes per house being the main driver of the reduction of the total domestic bug population. This ecologically safe approach is the first proven alternative to chemical insecticides in the control of T. infestans. The advantageous reduction in vector population by delayedaction fungal biopesticides in a contained environment is here shown supported by mathematical modeling.Fil: Forlani, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Pedrini, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Girotti, Juan Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Mijailovsky, Sergio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Cardozo, Rubén Marino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; Argentina. Provincia de Salta. Ministerio de Salud Pública. Coordinación de Gestión Epidemiológica; ArgentinaFil: Gentile, Alberto G.. Provincia de Salta. Ministerio de Salud Pública. Coordinación de Gestión Epidemiológica; ArgentinaFil: Hernández Suárez, Carlos. Universidad de Colima. Facultad de Ciencias; MéxicoFil: Rabinovich, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Juarez, Marta Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; Argentin

    In vitro comparative analysis of antiproliferative activity of essential oil from mandarin peel and its principal component limonene

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    The effects of the essential oil of mandarin peel (Corrientes, Argentina) and limonene (its major component) were studied on two human tumour cell lines growth (lung adenocarcinoma A549 and hepatocarcinoma HepG2). The essential oil was obtained by cold press and its composition was investigated by gas chromatography (GC) and GC/mass spectrometry (MS) analysis. The antiproliferative effect was studied using an MTT assay. Both mandarin essential oil and limonene tested showed a strong dose-dependent effect on the growth inhibition of these cell lines. The essential oil was more effective in A549 than in HepG2 cells and more effective than limonene in both the cases. It is likely that minor components and limonene of the oil could exert additive or synergistic effects. Hence, mandarin essential oil could lead to the development of anti-tumour agent or complementary and alternative medicines for the treatment of diverse cancers.Fil: Manassero, Carlos Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Girotti, Juan Roberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Mijailovsky, Sergio Javier. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: GarcĂ­a de Bravo, Margarita. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Polo, Monica Patricia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentin

    Control of pyrethroid-resistant chagas disease vectors with entomopathogenic fungi

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    Background: Triatoma infestans-mediated transmission of Tripanosoma cruzi, the causative agent of Chagas disease, remains as a major health issue in southern South America. Key factors of T. infestans prevalence in specific areas of the geographic Gran Chaco region - which extends through northern Argentina, Bolivia, and Paraguay - are both recurrent reinfestations after insecticide spraying and emerging pyrethroid-resistance over the past ten years. Among alternative control tools, the pathogenicity of entomopathogenic fungi against triatomines is already known; furthermore, these fungi have the ability to fully degrade hydrocarbons from T. infestans cuticle and to utilize them as fuel and for incorporation into cellular components. Methodology and Findings: Here we provide evidence of resistance-related cuticle differences; capillary gas chromatography coupled to mass spectrometry analyses revealed that pyrethroid-resistant bugs have significantly larger amounts of surface hydrocarbons, peaking 56.2±6.4% higher than susceptible specimens. Also, a thicker cuticle was detected by scanning electron microscopy (32.1±5.9 μm and 17.8±5.4 μm for pyrethroid-resistant and pyrethroid-susceptible, respectively). In laboratory bioassays, we showed that the virulence of the entomopathogenic fungi Beauveria bassiana against T. infestans was significantly enhanced after fungal adaptation to grow on a medium containing insect-like hydrocarbons as the carbon source, regardless of bug susceptibility to pyrethroids. We designed an attraction-infection trap based on manipulating T. infestans behavior in order to facilitate close contact with B. bassiana. Field assays performed in rural village houses infested with pyrethroid-resistant insects showed 52.4% bug mortality. Using available mathematical models, we predicted that further fungal applications could eventually halt infection transmission. Conclusions: This low cost, low tech, ecologically friendly methodology could help in controlling the spread of pyrethroid-resistant bugs.Facultad de Ciencias Médica

    The axial vector vertex in spiner electrodynamics and the analytic regularization method

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    Our purpose here is to re-examine some specific features of the axial vector vertex in spiner electrodynamics in the light; of the analytic regularization method in its gauge-invariant version given by Breitenlohner and Mitter to deal with closed fermion loops.Facultad de Ciencias Exacta

    On the regularization of quantum electrodynamics induced by nonpolynomial Lagrangians

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    Our purpose in this paper is to analyse the coupling of a real massless scalar field with the interacting Dirac-Maxwell fields through a nonpolynomial factor which simulates the presence of %/-- g. We give a proof that no such a thing as a superpropagator appears and, as consequence, the removal of infinities does not follow, at least in a straightforward manner, from the nonpolynomial character of the Lagrangian. The implied suggestion is that, if gravity plays a regularizing role in the theory, either its tensor character is essential for that purpose or the regularization is provided by other coupling.Departamento de FĂ­sic

    Some comments about a static-localized solution for the massive Thirring model

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    We derive the stability equation for a static-localized solution of the two-dimensional massive Thirring model. The corresponding eigenvalue spectrum is determined and compared with the eigenvalue spectrum of the stability equation for the soliton solution of the sine-Gordon theory.Facultad de Ciencias Exacta

    Biological Control of the Chagas Disease Vector <i>Triatoma infestans</i> with the Entomopathogenic Fungus <i>Beauveria bassiana</i> Combined with an Aggregation Cue: Field, Laboratory and Mathematical Modeling Assessment

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    Current Chagas disease vector control strategies, based on chemical insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant Triatoma infestans populations in the Gran Chaco region of South America. We have already shown that the entomopathogenic fungus Beauveria bassiana has the ability to breach the insect cuticle and is effective both against pyrethroid-susceptible and pyrethroid-resistant T. infestans, in laboratory as well as field assays. It is also known that T. infestans cuticle lipids play a major role as contact aggregation pheromones. We estimated the effectiveness of pheromone-based infection boxes containing B. bassiana spores to kill indoor bugs, and its effect on the vector population dynamics. Laboratory assays were performed to estimate the effect of fungal infection on female reproductive parameters. The effect of insect exuviae as an aggregation signal in the performance of the infection boxes was estimated both in the laboratory and in the field. We developed a stage-specific matrix model of T. infestans to describe the fungal infection effects on insect population dynamics, and to analyze the performance of the biopesticide device in vector biological control. The pheromone-containing infective box is a promising new tool against indoor populations of this Chagas disease vector, with the number of boxes per house being the main driver of the reduction of the total domestic bug population. This ecologically safe approach is the first proven alternative to chemical insecticides in the control of T. infestans. The advantageous reduction in vector population by delayed-action fungal biopesticides in a contained environment is here shown supported by mathematical modeling.Instituto de Investigaciones BioquĂ­micas de La PlataFacultad de Ciencias MĂ©dicasCentro de Estudios ParasitolĂłgicos y de Vectore

    Toxigenic Capacity and Trichothecene Production by <i>Fusarium graminearum</i> Isolates from Argentina and Their Relationship with Aggressiveness and Fungal Expansion in the Wheat Spike

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    At least 20 epidemics of Fusarium head blight (FHB) of wheat have been registered in the last 50 years in Argentina, with variable intensity. Damage induced by the disease is further aggravated by the presence of mycotoxins in affected grains that may cause health problems to humans and animals. The trichothecene chemotype was analyzed for 112 isolates of Fusarium graminearum from Argentina by polymerase chain reaction and two field trials were conducted to study the aggressiveness of a subsample of 14 representative isolates and to analyze deoxynivalenol (DON) production in planta and in vitro. All isolates belonged to the 15-acetyl-DON chemotype. Significant differences were observed in both the symptom severity induced in wheat spikes and the in vivoDON pro-duction, and a close correlation was found between these two variables. However, in vitro toxigenic potential was not correlated with the capacity of F. graminearum isolates to produce DON under natural conditions. The progress of infectionin the rachis of inoculated wheat spikes was analyzed and the pathogen presence verified in both symptomatic and symptomless spikes. Even isolates with a limited capacity to induce symptoms were able to colonize the vascular tissue and to produce considerable amounts of DON in planta.Facultad de Ciencias Agrarias y Forestale
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