1,500 research outputs found

    Applications of the Virtual Element Method to Discrete Fracture Networks

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    We put forward in this work several novel applications of the Virtual Element Method in the context of Discrete Fracture Networks. A family of methods is presented here for solving Darcy flow, time dependent-problems and the complete transport equation in both diffusion-dominated and convection-dominated problems. We present as well an implementation of mixed Virtual Elements in the context of Discrete Fracture Networks

    First report of Leptosphaeria biglobosa ‘brassicae’ as causal agent of phoma leaf spot in Brassica napus (Canola) in Argentina

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    Canola(Brassicanapus L.) is the second largest oilseed crop in the worldproviding 13% of the world´s oil supply. This crop has been grown in Argentinasince the 1930s, and the area devoted to its cultivation varies every year,reaching a maximum of 95000 Ha in the 2012/2013 growing season. Because of theoccurrence of optimal weather conditions and soils with high fertility, theaverage yield in this region is about 2000 kg/Ha. Phoma leaf spot and Phomastem canker are considered the most important and devastating diseases in Brassica napus andother Brassicaespecies [1]. In both cases, the causal agent is a complexof two closely related fungal species, Leptosphaeria maculans and L. biglobosa. In Argentina,the presence of L. maculans incanola plants was reported for the first time in 2004 [2], but the existence ofL.biglobosa has not been recorded so far. During the 2015/2016season, we collected several samples with typical Phoma leaf spot symptoms fromcanola plants growing in fields from the north and northeastern regions of the Buenos Aires province.The necrotic lesions were circular to irregularly oval, 8 to 15 mm in diameter,pale brown in the center, grayish green at the margin and characterized withthe presence of pycnidia. Several leaf pieces with lesions were rinsed twicewith deionized sterile water and placed in a humid chamber (90 mm diameterPetri dish with a layer of filter paper soaked in deionized sterile water) during2-3 days to induce the pycnidia to exude cirri of conidia. After this period,one cirrus per sample was transferred onto PDA plates supplemented withantibiotics (15 mg/L streptomycin, 15 mg/L gentamicin and 12 mg/L tetracycline)using an inoculation needle under stereoscopic microscope. Thus, severalisolates were obtained, some of them showing rapid mycelial growth rate andpigment production on PDA medium, as showed by the isolate Tapidor of L. biglobosa thatwe used as control (kindly provided by Professor Bruce Fitt, University ofHertfordshire-UK). In order to confirm the identity of these isolates, a PCRassay using genomic DNA as template was performed to distinguish L. maculans from L. biglobosa withthe species-specific primers LmacR, LmacF,and LbigF ina three-primers strategy described by Gaetan (2005)[3]. These reactions gave a444-bp amplicon as expected for L. biglobosa ´brassicae´.In addition, these results were confirmed by sequencing the nuclear ribosomalinternal transcribed spacer (ITS) region, which showed a 99% of identity withthe sequence of L. biglobosa ´brassicae´at the GenBank database (FO905468). L. biglobosa isolateswere then tested for pathogenicity on the canola cultivars Westar and Bioaureo2286 (Nuseed). With this purpose, cotyledons of 10-day-old seedlings werepricked with a needle, and each wound inoculated with 10 μl ofa conidial suspension (107 42conidia/ml). Sterilized distilled water was used as control. Developing primaryleaves were removed every 2-3 days in order to ensure that cotyledons continueto expand. Fourteen days after inoculation, irregular and brown necroticlesions were visible at the site of inoculation. These cotyledons were detachedand placed in a humid chamber to induce pycnidia formation. After three dayscirri of conidia were transferred to a plate with PDA supplemented with antibioticsas mentioned above. The identity of these isolates of L. biglobosa wereconfirmed by pigment production on PDA medium and by PCR assay usingspecies-specific primers. To our knowledge, this is the first report of L. biglobosa ´brassicae´as a pathogen of canola in Argentina. This finding shows that in Argentina´scanola cropping areas not 50 only L. maculans but alsoL.biglobosa are the causal agents of Phoma leaf spot disease.Fil: Rossi, Franco Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Romero, Fernando Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Garriz, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Ruiz, Oscar Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; Argentin

    Ceticismo e reconhecimento : outras mentes, racionalidade e linguagem

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    Esta tese de doutorado é uma investigação do conceito de reconhecimento e das suas conexões com o problema do conhecimento de outras mentes e de outras vontades. Este conceito é oferecido como uma forma de dissolver o problema cético de outras mentes, mas na mesma medida em que ele dissolve o problema, tal conceito abre um rico campo de exploração filosófica. O conceito de reconhecimento resulta do fracasso das tentativas de atender a demanda cética por certeza da existência de outras mentes. O fracasso desta empreitada epistemológica implica um recuo onde se passa a analisar as bases da significatividade do conceito de mente. Uma vez analisadas as condições de sua significatividade, o problema cético será compreendido na sua origem e passarei a investigar os diferentes modos de relação com o outro. O resultado será a possibilidade de conhecimento de outras mentes, não como função do conceito de certeza, mas como forma do reconhecimento do outro. A partir de então passo a investigar a gramática do fenômeno de reconhecimento — sua unidade, a lógica pronominal que a compõe, as formas autênticas de reconhecimento por contraste com as formas projetivas do eu e finalmente a conexão entre conhecer outras mentes e o reconhecimento do outro como um ser dotado de vontade.This dissertation investigates de concept of recognition and its connections with the problem of other minds and other wills. This concept is presented as a way to dissolve the skeptical problem of other minds, and as a further consequence it also opens a rich field of philosophical investigation. The concept of recognition is first grasped in the responses to the skeptic’s demand for certainty about the existence of other minds. The modern epistemological enterprise’s failure conduced philosophers to step back from the original problem and motivated a new posture in the analysis of the concept of mind. Once this task was accomplished, the skeptical problem is understood in its origins and this enables the investigation of the different modes of relation to the other. The result will be the possibility of knowledge of other minds, however not as a function of the concept of certainty, but as a form of recognition of other minds. This dissertation will also seek the understanding of the grammar of recognition — its unity, the pronouns that constitute its logic, the authentic forms of recognition and finally the connection between knowing other minds and the acknowledgment of the other as a being gifted with his/her own will

    ERT and the Location of Mining Cavities in Anisotropic Media: A Field Example

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    Often cave location requires the use of surface indirect techniques, such as geophysical methods. In particular, electrical methods have been applied to cavity exploration with evident success. However, as any other indirect methods, the use of these techniques has advantages and disadvantages. Cavities may be too small, too deep or masked by local geology to be detected. Nevertheless, indirect methods provide non-invasive, low cost and fast techniques to carry out the reconnaissance of an area where the presence of cavities is suspected. Complex geological conditions and formations anisotropy can induce strong orientational variation on ground resistivity measurements and, therefore, mask the presence of caves. Herein a field study in an old mining area demonstrates that 2D resistivity data—electrical resistivity tomography (ERT)—can be strongly affected by local anisotropy that masks the presence of cavities in ERT data modelling. In these cases, specific field strategies must be considered to overcome misleading interpretations and modelling, so that, meaningful results are obtained, uncertainty and interpretation ambiguity are reduced and the correct diagnosis of caves is accomplished

    Dispersal and population structure at different spatial scales in the subterranean rodent Ctenomys australis

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    This study was funded by grants from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, PIP5838), Agencia de Promoción Científica y Tecnológica de la Argentina (PICTO1-423, BID-1728/OC-AR), and the programme ECOS-Sud France/Argentina (A05B01).Background: The population genetic structure of subterranean rodent species is strongly affected by demographic (e.g. rates of dispersal and social structure) and stochastic factors (e.g. random genetic drift among subpopulations and habitat fragmentation). In particular, gene flow estimates at different spatial scales are essential to understand genetic differentiation among populations of a species living in a highly fragmented landscape. Ctenomys australis (the sand dune tuco-tuco) is a territorial subterranean rodent that inhabits a relatively secure, permanently sealed burrow system, occurring in sand dune habitats on the coastal landscape in the south-east of Buenos Aires province, Argentina. Currently, this habitat is threatened by urban development and forestry and, therefore, the survival of this endemic species is at risk. Here, we assess population genetic structure and patterns of dispersal among individuals of this species at different spatial scales using 8 polymorphic microsatellite loci. Furthermore, we evaluate the relative importance of sex and habitat configuration in modulating the dispersal patterns at these geographical scales. Results: Our results show that dispersal in C. australis is not restricted at regional spatial scales (similar to 4 km). Assignment tests revealed significant population substructure within the study area, providing support for the presence of two subpopulations from three original sampling sites. Finally, male-biased dispersal was found in the Western side of our study area, but in the Eastern side no apparent philopatric pattern was found, suggesting that in a more continuous habitat males might move longer distances than females. Conclusions: Overall, the assignment-based approaches were able to detect population substructure at fine geographical scales. Additionally, the maintenance of a significant genetic structure at regional (similar to 4 km) and small (less than 1 km) spatial scales despite apparently moderate to high levels of gene flow between local sampling sites could not be explained simply by the linear distance among them. On the whole, our results support the hypothesis that males disperse more frequently than females; however they do not provide support for strict philopatry within females.Publisher PDFPeer reviewe

    Ethnozoology in the mountains. What does the cognitive salience of wild animals tell us?

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    In recent times, ethnobiology has revived interest in cognitive aspects of humans' communities. A concept commonly used in this area is cognitive salience. In this paper we assess the wild animal salience meaning for the rural people from an area of the mountain range of the Cordoba province (Argentina). We also analyzed the relationship of cultural and ecological factors over wild animal domain salience. The values of cognitive salience, perception and cultural value were obtained by means of free lists to 16 collaborators, while semistructured interviews were used to inquire about local ecological knowledge and ease of observation about wild animals. The interdependence between the five variables elaborated was analyzed through a Principal Components Regression. The results show a qualitative relationship between Cognitive Salience and Cultural Value and a significant correlation between Cognitive Salience and Local Ecological Knowledge. Ease of Observation did not correlate with Cognitive Salience, but show a significant relationship with the Perceived Abundance. The results suggest a complex network of factors that are modeling the cognitive salience and local perceptions over wild animals. In our findings, highlight the Cultural Value given to harmful animals which reflects an increasing pattern in the region, the conflict between rural people and wild animals. In turn a mutual influences and causal feedback loops between cognitive salience and an ecological factor, the Perceived abundance, is proposed. Investigations over cognition and about how people perceived nature can give us an idea of how they act in it, a compelling factor when it comes to cultural and biological conservation issues.Fil: Wajner, Matias. No especifíca;Fil: Tamburini, Daniela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Zamudio, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

    Efficient combustion parameter prediction and performance optimization for a diesel engine with a low throughput combustion model

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    In this work, an efficient implementation of a zero-dimensional model is described for the estimation of key engine parameters for combustion control in compression-ignition engines. The direct problems of the estimation of the angle of 50% of fuel mass fraction burnt (MFB50) and of the mean effective pressure (IMEP) are addressed as well as the inverse problems of determining optimal start of injection (SOI) timing for target values of MFB50 and IMEP. The main focus is on the computational cost of the algorithms proposed, designed in order to keep the number of operations as low as possible without compromising the applicability of the methods to different engine configurations and operation points. Execution time of the order of few milliseconds are achieved for parameters prediction and of the order of one tenth of a second for the optimization problems, such that an implementation in engine ECU for model-based control purposes can be envisaged
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