60 research outputs found

    Discontinuidades estratigráficas en el Jurásico de Sierra Gorda (Subbético intnerno, Provincia de Granada)

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    En el Jurásico de la unidad de Sierra Gorda (Subbético interno, prov. Granada) se reconocen cinco discontinuidades estratigráficas:en el Carixiense, en la base del Dogger, en la base del Calloviense en la base del Oxfordense y en el Kimmeridgiense. En el sector septentrional de la unidad se detectan por superficies de omisión y hardgrounds, mientras que en el borde meridional muesitran gran desarrollo de diques neptúnicos

    La sedimentación liásica en el sector central del Subbético medio: registro de la evolución de un rift intracontinental

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    Durante el Lias medio tuvo lugar el paso brusco de la sedimenta-ción carbonatada somera a la pelágica en la Zona Subbética, en relación con la evolución de un rift intracontinental. Se han podido delimitar cuatro etapas con sus sedimentos correspondientes: a) Etapa prerruptura (sedimentación marina somera). b) Inicio de la rup-tura (hardgrounds y paleokarst). c) Comienzo de la sedimentación hemipelágica (niveles de calizas  condensadas). d) Individualización del surco subbético (ritmita  calizas/margas)

    Influencia de la hipotermia sobre la absorción intestinal de distintas sustancias

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    The influence of hypothermia on arabinose, calcium, glucose and lysine intestinal absorption was studied in anesthetized rats by means of «in situ» whole small bowell perfusion; two lots of animals with rectal temperatures of 37 ± 1º C and 24 ± 1º C were compared. Arabinose absorption was not reduced by hypothermia; calcium absorption at 24 ± 10 C fall to zéro when it is in intestinal lumen at the same concentration than in plasma, and was significantly reduced when luminal concentration is three times bigger than plasmati'c one. In our experimental conditions hypothermia reduced only slightly glucose intestinal absorption. L-Lysine transport was markedly inhibited by low temperatures.Se ha estudiado la influencia de la hipotermia sobre la absorción intestinal de arabinosa, calcio, glucosa y lisina, en ratas anestesiadas, mediante perfusión «in situ» de la totalidad del intestino delgado, y comparando dos lotes deanimales con temperaturas rectales de 37 ± 1° C y 24 ± 1º C. La absorción de arabinosa no se reduce por la hipotermia, la absorción de calcio a 24 ± 1º C se hace nula cuando dicho catión se encuentra en la luz del intestino a concentración igual que en el plasma, y dismdnuye significativamente cuando la concentración luminal es triple de la plasmática. En nuestras condrciones experimentales la hipotermda reduce sólo ligeramente la absorción intestinal de glucosa. El transporte de L-lisina se inhibe marcadamente por efecto de las bajas temperaturas

    Detection and Characterization of a Distinct Bornavirus Lineage from Healthy Canada Geese (\u3ci\u3eBranta canadensis\u3c/i\u3e)

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    Avian bornaviruses (ABV), identified in 2008, infect captive parrots and macaws worldwide. The natural reservoirs of these viruses are unknown. Reverse transcription-PCR (RT-PCR) was used to screen oropharyngeal/ cloacal swab and brain samples from wild Canada geese (Branta canadensis) for ABV. Approximately 2.9% of swab samples were positive for bornavirus sequences. Fifty-two percent of brain samples from 2 urban flocks also tested positive, and brain isolates were cultured in duck embryo fibroblasts. Phylogenetic analyses placed goose isolates in an independent cluster, and more notably, important regulatory sequences present in Borna disease virus but lacking in psittacine ABVs were present in goose isolates

    Secreción de bicarbonato en íleon terminal de conejo

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    Se estudia el movimiento de bicarbonato y cloruro en un asa "in situ" de ileón terminal de conejo. Las concentraciones de Cl-, C03H-, Na+ y K+ se analizan tras media hora de permanencia de las soluciones en el asa. Existe un movimiento de cloruro mucosa-serosa desde concentraciones iniciales de este anión de 58 mEq/l. En el caso del bicarbonato tiene lugar un movimiento serosa-mucosa, incluso cuando la solución contiene 67 mEq/l de C03H-, niveles muy superiores a los plasmáticos, indicando que en el ileón terminal de conejo existe un proceso activo de secreción de bicarbonato. Hecho que se confirma al someter los animales en situación de hipotermia, en que la secreción de bicarbonato se hace casi nula para una solución que contiene una concentración de bicarbonato similar a la plasmática.We have studied the changes of bicarbonate and chloride in a loop «in Sittu> of terminal ileum of rabbit. We analysed the concentration of N a+, K+, 01- and COaH- after half and hour that solutions have been remaining in the loop. There is a movement mucosa-serosa of chloride from a concentration initial of 58 mEq/l. In the case of bicarbonate takes place a movement serosa-mucosa, even when the solution contains 67 mEq/l, higher level than In the plasma, this indicates in terminal ileum of rabbits that exist an active process of secretion of bicarbonate. We can confirm the existence of this mechanism in hypothermia. In these conditions the secretion of bicarbonate in almost nule for a solution containing a concentration of bicarbonate similar to the plasma

    Hybrid case‑base maintenance approach for modeling large scale case‑based reasoning systems

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    YesCase-based reasoning (CBR) is a nature inspired paradigm of machine learning capable to continuously learn from the past experience. Each newly solved problem and its corresponding solution is retained in its central knowledge repository called case-base. Withρ the regular use of the CBR system, the case-base cardinality keeps on growing. It results into performance bottleneck as the number of comparisons of each new problem with the existing problems also increases with the case-base growth. To address this performance bottleneck, different case-base maintenance (CBM) strategies are used so that the growth of the case-base is controlled without compromising on the utility of knowledge maintained in the case-base. This research work presents a hybrid case-base maintenance approach which equally utilizes the benefits of case addition as well as case deletion strategies to maintain the case-base in online and offline modes respectively. The proposed maintenance method has been evaluated using a simulated model of autonomic forest fire application and its performance has been compared with the existing approaches on a large case-base of the simulated case study.Authors acknowledge the internal funding support received from Namal College Mianwali to complete the research work

    Turbot reovirus (SMReV) genome encoding a FAST protein with a non-AUG start site

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    <p>Abstract</p> <p>Background</p> <p>A virus was isolated from diseased turbot <it>Scophthalmus maximus </it>in China. Biophysical and biochemical assays, electron microscopy, and genome electrophoresis revealed that the virus belonged to the genus <it>Aquareovirus</it>, and was named <it>Scophthalmus maximus </it>reovirus (SMReV). To the best of our knowledge, no complete sequence of an aquareovirus from marine fish has been determined. Therefore, the complete characterization and analysis of the genome of this novel aquareovirus will facilitate further understanding of the taxonomic distribution of aquareovirus species and the molecular mechanism of its pathogenesis.</p> <p>Results</p> <p>The full-length genome sequences of SMReV were determined. It comprises eleven dsRNA segments covering 24,042 base pairs and has the largest S4 genome segment in the sequenced aquareoviruses. Sequence analysis showed that all of the segments contained six conserved nucleotides at the 5' end and five conserved nucleotides at the 3' end (5'-GUUUUA ---- UCAUC-3'). The encoded amino acid sequences share the highest sequence identities with the respective proteins of aquareoviruses in species group <it>Aquareovirus </it>A. Phylogenetic analysis based on the major outer capsid protein VP7 and RNA-dependent RNA polymerase were performed. Members in <it>Aquareovirus </it>were clustered in two groups, one from fresh water fish and the other from marine fish. Furthermore, a fusion associated small transmembrane (FAST) protein NS22, which is translated from a non-AUG start site, was identified in the S7 segment.</p> <p>Conclusions</p> <p>This study has provided the complete genome sequence of a novel isolated aquareovirus from marine fish. Amino acids comparison and phylogenetic analysis suggested that SMReV was a new aquareovirus in the species group <it>Aquareovirus </it>A. Phylogenetic analysis among aquareoviruses revealed that VP7 could be used as a reference to divide the aquareovirus from hosts in fresh water or marine. In addition, a FAST protein with a non-AUG start site was identified, which partially contributed to the cytopathic effect caused by the virus infection. These results provide new insights into the virus-host and virus-environment interactions.</p

    Critical Role of the Virus-Encoded MicroRNA-155 Ortholog in the Induction of Marek's Disease Lymphomas

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    Notwithstanding the well-characterised roles of a number of oncogenes in neoplastic transformation, microRNAs (miRNAs) are increasingly implicated in several human cancers. Discovery of miRNAs in several oncogenic herpesviruses such as KSHV has further highlighted the potential of virus-encoded miRNAs to contribute to their oncogenic capabilities. Nevertheless, despite the identification of several possible cancer-related genes as their targets, the direct in vivo role of virus-encoded miRNAs in neoplastic diseases such as those induced by KSHV is difficult to demonstrate in the absence of suitable models. However, excellent natural disease models of rapid-onset Marek's disease (MD) lymphomas in chickens allow examination of the oncogenic potential of virus-encoded miRNAs. Using viruses modified by reverse genetics of the infectious BAC clone of the oncogenic RB-1B strain of MDV, we show that the deletion of the six-miRNA cluster 1 from the viral genome abolished the oncogenicity of the virus. This loss of oncogenicity appeared to be primarily due to the single miRNA within the cluster, miR-M4, the ortholog of cellular miR-155, since its deletion or a 2-nucleotide mutation within its seed region was sufficient to inhibit the induction of lymphomas. The definitive role of this miR-155 ortholog in oncogenicity was further confirmed by the rescue of oncogenic phenotype by revertant viruses that expressed either the miR-M4 or the cellular homolog gga-miR-155. This is the first demonstration of the direct in vivo role of a virus-encoded miRNA in inducing tumors in a natural infection model. Furthermore, the use of viruses deleted in miRNAs as effective vaccines against virulent MDV challenge, enables the prospects of generating genetically defined attenuated vaccines

    Multi-agent modeling of the South Korean avian influenza epidemic

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    <p>Abstract</p> <p>Background</p> <p>Several highly pathogenic avian influenza (AI) outbreaks have been reported over the past decade. South Korea recently faced AI outbreaks whose economic impact was estimated to be 6.3 billion dollars, equivalent to nearly 50% of the profit generated by the poultry-related industries in 2008. In addition, AI is threatening to cause a human pandemic of potentially devastating proportions. Several studies show that a stochastic simulation model can be used to plan an efficient containment strategy on an emerging influenza. Efficient control of AI outbreaks based on such simulation studies could be an important strategy in minimizing its adverse economic and public health impacts.</p> <p>Methods</p> <p>We constructed a spatio-temporal multi-agent model of chickens and ducks in poultry farms in South Korea. The spatial domain, comprised of 76 (37.5 km × 37.5 km) unit squares, approximated the size and scale of South Korea. In this spatial domain, we introduced 3,039 poultry flocks (corresponding to 2,231 flocks of chickens and 808 flocks of ducks) whose spatial distribution was proportional to the number of birds in each province. The model parameterizes the properties and dynamic behaviors of birds in poultry farms and quarantine plans and included infection probability, incubation period, interactions among birds, and quarantine region.</p> <p>Results</p> <p>We conducted sensitivity analysis for the different parameters in the model. Our study shows that the quarantine plan with well-chosen values of parameters is critical for minimize loss of poultry flocks in an AI outbreak. Specifically, the aggressive culling plan of infected poultry farms over 18.75 km radius range is unlikely to be effective, resulting in higher fractions of unnecessarily culled poultry flocks and the weak culling plan is also unlikely to be effective, resulting in higher fractions of infected poultry flocks.</p> <p>Conclusions</p> <p>Our results show that a prepared response with targeted quarantine protocols would have a high probability of containing the disease. The containment plan with an aggressive culling plan is not necessarily efficient, causing a higher fraction of unnecessarily culled poultry farms. Instead, it is necessary to balance culling with other important factors involved in AI spreading. Better estimations for the containment of AI spreading with this model offer the potential to reduce the loss of poultry and minimize economic impact on the poultry industry.</p
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