1,071 research outputs found

    Estrategia de Andrews en el simulador de negocios Capstone

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    En este trabajo de obtención de grado, representa la experiencia de los autores de dicho documento al ser expuestos un ambiente simulado volátil de negocios fomentando poner en práctica los conocimientos que se obtuvieron durante la maestría. El capítulo uno contiene el marco teórico, en el que se desarrollan conceptos de planeación estratégica y en el que además se hacen revisiones de casos de diferentes empresas internacionales bajo este concepto. Se incluyen también temas de liderazgo estratégico y estructuras de modelos de negocio. El capítulo dos, describe las características y conceptos del simulador Capstone, y se agrega el desarrollo y diseño de la estrategia de Andrews, que se aplica en la simulación del negocio en los ocho periodos. Del capítulo tres al seis, se incluye el análisis de los resultados obtenidos por Andrews en cada uno de los periodos del simulador, se hacen comparativos de dichos resultados con los competidores, en las áreas de desarrollo en investigación, producción, mercadotecnia y finanzas principalmente. El capítulo siete, se refiere a las conclusiones generales de la simulación, así como de la experiencia personal de la modalidad de simulación y de la maestría estudiada en el ITESO. Así pues, este trabajo de obtención de grado, es una prueba del resultado de los conocimientos obtenidos y puestos en práctica de los autores.ITESO, A.C

    Anthropogenic radionuclides in the water column and a sediment core from the Alboran Sea: application to radiometric dating and reconstruction of historical water column radionuclide concentrations

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    Global fallout is the main source of anthropogenic radionuclides in the Mediterranean Sea. This work presents 137Cs, 239+240Pu and 241Am concentrations in the water column in the southwest Alboran Sea, which was sampled in December 1999. A sediment core was taken at 800 m depth in the area (35°47′ N, 04°48′ W). 210Pb, 226Ra, 137Cs and 239+240Pu specific activities were measured at multiple depths in the core for dating purposes. 137Cs and 239+240Pu profiles did not show defined peaks that could be used as time markers, and they extended up to depths for which the 210Pb-based constant rate of supply (CRS) dating model provided inconsistent dates. These profiles can be useful to test dating models, understood as particular solutions of a general advection–diffusion problem, if the time series of radionuclide inputs into the sediment is provided. Thus, historical records of depth-averaged 137Cs and 239+240Pu concentrations in water, and their corresponding fluxes into the sediment, were reconstructed. A simple water-column model was used for this purpose, involving atmospheric fallout, measured distribution coefficient (k d) values, and a first-estimate of sedimentation rates. A dating model of constant mixing with constant sedimentation rate was applied successfully to three independent records (unsupported 210Pb, 137Cs and 239+240Pu), and provided the objective determination of mixing parameters and mass sedimentation rate. These results provide some insight into the fate of atmospheric inputs to this marine environment and, particularly, into the contribution from the Chernobyl accident.International Atomic Energy Agency Research Project RAF/7/00

    Catalytical Properties of Free and Immobilized Aspergillus niger Tannase

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    A fungal tannase was produced, recovered, and immobilized by entrapment in calcium alginate beads. Catalytical properties of the immobilized enzyme were compared with those of the free one. Tannase was produced intracellularly by the xerophilic fungus Aspergillus niger GH1 in a submerged fermentation system. Enzyme was recovered by cell disruption and the crude extract was partially purified. The catalytical properties of free and immobilized tannase were evaluated using tannic acid and methyl gallate as substrates. KM and Vmax values for free enzyme were very similar for both substrates. But, after immobilization, KM and Vmax values increased drastically using tannic acid as substrate. These results indicated that immobilized tannase is a better biocatalyst than free enzyme for applications on liquid systems with high tannin content, such as bioremediation of tannery or olive-mill wastewater

    Assessing the distribution of the Argentine ant using physiological data

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    To address the lack of physiological approaches in current models assessing the potential distribution of the Argentine ant, we used data on brood development from distinct sources to evaluate a series of degreeday models for Catalonia (NE Iberian Peninsula), and data on the brood survival and oviposition rates to develop a worker production model. The degree-day model generated using data from Newell and Barber (1913) and Benois (1973) indicated that the number of degree-days required for the complete development from egg to adult worker was 445.4 degree-days above a threshold of 15.9°C, while the model calibratedusing data from Abril et al. (2008, in press) suggested 599.5 degree-days above 18.4°C. Comparisons between the degree-day model predictions and the currently known distribution of the Argentine ant suggested that the one generated using data from Newell and Barber (1913) and Benois (1973) overestimated the presence of the species, while the one calibrated using data from Abril et al. (2008; in press) underestimated it. On the other hand, the predicted daily net production of Argentine ant workers generated by the worker production model predicted more accurately the distribution of the Argentine ant than the degree-day models. Our results show the utility of incorporating physiological data in models to assess the distribution limits of the Argentine ant, which up to date have taken little account of the physiological needs of the species in terms of its establishment and dispersion in its introduced ranges.Centre of Excellence for Invasion Biolog

    BANCO CENTRAL DO BRASIL

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    Dispõe sobre as diretrizes que devem ser observadas no estabelecimento e na implementação da Política de Responsabilidade Socioambiental pelas instituições financeiras e demais instituições autorizadas a funcionar pelo Banco Central do Brasil

    Metagenomics for the study of viruses in urban sewage as a tool for public health surveillance

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    The application of next-generation sequencing (NGS) techniques for the identification of viruses present in urban sewage has not been fully explored. This is partially due to a lack of reliable and sensitive protocols for studying viral diversity and to the highly complex analysis required for NGS data processing. One important step towards this goal is finding methods that can efficiently concentrate viruses from sewage samples. Here the application of a virus concentration method based on skimmed milk organic flocculation (SMF) using 10 L of sewage collected in different seasons enabled the detection of many viruses. However, some viruses, such as human adenoviruses, could not always be detected using metagenomics, even when quantitative PCR (qPCR) assessments were positive. A targeted metagenomic assay for adenoviruses was conducted and 59.41% of the obtained reads were assigned to murine adenoviruses. However, up to 20 different human adenoviruses (HAdV) were detected by this targeted assay being the most abundant HAdV-41 (29.24%) and HAdV-51 (1.63%). To improve metagenomics' sensitivity, two different protocols for virus concentration were comparatively analysed: an ultracentrifugation protocol and a lower-volume SMF protocol. The sewage virome contained 41 viral families, including pathogenic viral species from families Caliciviridae, Adenoviridae, Astroviridae, Picornaviridae, Polyomaviridae, Papillomaviridae and Hepeviridae. The contribution of urine to sewage metavirome seems to be restricted to a few specific DNA viral families, including the polyomavirus and papillomavirus species. In experimental infections with sewage in a rhesus macaque model, infective human hepatitis E and JC polyomavirus were identified. Urban raw sewage consists of the excreta of thousands of inhabitants; therefore, it is a representative sample for epidemiological surveillance purposes. The knowledge of the metavirome is of significance to public health, highlighting the presence of viral strains that are circulating within a population while acting as a complex matrix for viral discovery. (c) 2017 Elsevier B.V. All rights reserved

    Phytochemical, antioxidant and antimicrobial parameters of essential oils and hydrosols of colombian Thyme and Rosemary obtained using two different steam distillation methods

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    Two procedures of steam distillation of Rosmarinus officinalis and Thymus vulgaris were compared by phytochemical, antioxidant and antimicrobial analysis of their respective essential oils and hydrosols using respectively GCFID and GCMS analysis, free radical scavenging activity on ABTS and dilution and diffusion method against 3 bacteria and 2 fungi. Differences in bioactivity results are discussed taking into account changes in molecular content of essential oils and hydrosols obtained by the two different distillation methods. Although no significant difference was observed between the two procedures with Rosmarinus officinalis, that was not the case with Thymus vulgaris. Significant differences were noted, not only in their respective chemical composition especially with the thymol and p-cymene percentage with respectively a change from 39% with conventional steam distillation to 27% with adapted steam distillation for thymol and from 28% with the first distillation to 37% with the second one for p-cymene. These phytochemical composition changes have an impact on their biological activities results and consequently on the therapeutic activities expected which shows the importance of distillation method selection

    First Report and Comparative Genomics Analysis of a blaOXA-244-Harboring Escherichia coli Isolate Recovered in the American Continent

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    The carbapenemase OXA-244 is a derivate of OXA-48, and its detection is very difficult in laboratories. Here, we report the identification and genomic analysis of an Escherichia coli isolate (28Eco12) harboring the blaOXA-244 gene identified in Colombia, South America. The 28Eco12 isolate was identified during a retrospective study, and it was recovered from a patient treated in Colombia. The complete nucleotide sequence was established using the PacBio platform. A comparative genomics analysis with other blaOXA-244–harboring Escherichia coli strains was performed. The 28Eco12 isolate belonged to sequence type (ST) 38, and its genome was composed of two molecules, a chromosome of 5,343,367 bp and a plasmid of 92,027 bp, which belonged to the incompatibility group IncY and did not harbor resistance genes. The blaOXA-244 gene was chromosomally encoded and mobilized by an ISR1-related Tn6237 composite transposon. Notably, this transposon was inserted and located within a new genomic island. To our knowledge, this is the first report of a blaOXA-244–harboring Escherichia coli isolate in America. Our results suggest that the introduction of the OXA-244-producing E. coli isolate was through clonal expansion of the ST38 pandemic clone. Other isolates producing OXA-244 could be circulating silently in America.</jats:p

    Identification of reference genes for real-time PCR cytokine gene expression studies in sheep experimentally infected with Fasciola hepatica

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    The aim of this study was to validate reference genes for gene normalisation using qRT-PCR in hepatic lymph nodes (HLN) and livers from sheep infected with Fasciola hepatica during early and late stages of infection. To this end, a comprehensive statistical approach (RefFinder) encompassing four different methods of analysis (geNorm, BestKeeper, ΔCt method and NormFinder) was used to validate ten candidate reference genes. Stability analysis of gene expression followed by pairwise variation (Vn/Vn + 1) analysis revealed that PGK1, HSP90AA1 and GYPC were the most stable reference genes and suitable for qRT-PCR normalisation in both HLN and liver tissues. These three genes were validated against FoxP3, IL-10, TGF-β, TNF-α and IL-1β genes in the HLN tissue of sheep vaccinated with Cathepsin L1 from F. hepatica and unvaccinated infected and uninfected controls during early stages of infection. In the liver, the three reference genes were validated against TNF-α and IL-1β during chronic stages of infection with F. hepatica and in uninfected controls. Our study is the first to evaluate and validate sheep reference genes in order to provide tools for monitoring cytokines in Fasciola hepatica infected sheep target organs. Our results present an approach to elucidate the role of different cytokines in F. hepatica vaccinated and infected shee
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