72 research outputs found

    Campamento Vespucio, una nueva localidad con mamíferos pleistocenos en la provincia de Salta, Argentina

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    In this contribution a new locality with Pleistocene fossil mammals is presented. The materials come from the Quebrada del Aguay, Campamento Vespucio, General Mosconi, Salta province, Argentina; they are tentatively assigned to the Urundel Fm. (late Pleistocene). The palaeofaunistic association includes six taxa: Xenarthra Glyptodontidae: Glyptodon sp. and Panochthidae: Neosclerocalyptus sp.; Tardigrada Megatheriidae: gen. et. sp. indet.; Proboscidea Gomphotheriidae: Stegomastodon sp; Notoungulata Toxodontidae: Toxodon sp. Perissodactyla Equidae: Equus (Amerhippus) sp. This set of Pleistocene mammals presents a wide latitudinal distribution in South America. Some of them (e.g. Neosclerocalyptus) are congruent with arid/semiarid, cold conditions and open environments. In this scenario, this contribution improves the knowledge that we have in northern part of Argentina, very scarce compared with respect to that of the Pampean region.En la presente contribución damos a conocer una nueva localidad con mamíferos fósiles pleistocenos, provenientes de una región poco explorada. Los materiales fueron hallados en la Quebrada del Aguay, en Campamento Vespucio, localidad de General Mosconi, provincia de Salta, Argentina, y tentativamente asignados a la Fm. Urundel (Pleistoceno tardío). Desde un punto de vista taxonómico, se presentan seis taxones que incluyen: Xenarthra Glyptodontidae: Glyptodon sp. y Panochthidae: Neosclerocalyptus sp.; Tardigrada Megatheriidae: gen. et. sp. indet; Proboscidea Gomphotheriidae: Stegomastodon sp; Notoungulata Toxodontidae: Toxodon sp.; Perissodactyla Equidae: Equus (Amerhippus) sp. Este elenco faunístico se encuentra representado por taxones que presentan una amplia distribución latitudinal en América del Sur. Algunos de ellos (e.g. Neosclerocalyptus) indicadores de climas áridos/semiáridos y fríos de ambientes abiertos. Por último, este trabajo contribuye a mejorar la caracterización paleofaunística del Pleistoceno del norte de Argentina, muy poco conocida con respecto a aquella de la región Pampeana

    Actinomyces pyogenes CAUSANTE DE ABORTO EN BOVINOS

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    Se describe un caso de aborto bovino debido a la bacteria Actinomyces pyogenes ocurrido en un hato lechero del valle de Cieneguilla, Lima, Perú. El feto de 4 meses de desarrollo fue abortado en completo estado de autolisis y fue remitido al laboratorio para su análisis. En la necropsia, la única lesión macroscópica observada fue de unos pequeños nódulos blanquecinos en el pulmón. Se colectó muestras de diferentes tejidos como riñón, pulmón, corazón y encéfalo para el descarte del virus de la diarrea viral bovina (VDVB) y Neospora caninum mediante pruebas inmunohistoquímicas y para el cultivo bacteriano. No se detectó antígenos del VDVB ni de N. caninum en los tejidos del feto, pero se aisló en cultivo puro una bacteria identificada bioquímicamente como A. pyogenes. El examen histopatológico del pulmón indicó una moderada a severa bronconeumonía supurativa aguda asociada a bacterias. El aislamiento de la bacteria en forma pura, la ausencia de otros agentes abortogénicos y las lesiones histopatológicas de los tejidos del feto indicaron que el aborto fue debido a A. pyogenes.A case of bovine fetal abortion due to Actinomyces pyogenes in a dairy herd of Cieneguilla valley of Lima, Peru is reported. A bovine fetus of four monts of gestation was aborted and submitted for laboratory examination. Macroscopic lesions in fetal tissues were not found with the exception of numerous white foci up to 1mm in diameter in diameter in the lungs. Various fetal tissue samples were collected for virologic, bacteriologic and histopathologic examinations. Bovine viral diarrhea virus (BVDV) and Neospora caninum antigen were ruled out by immunohistochemistry but, pure colonies of A. pyogenes were isolated from the lung and other fetal tissues. The microscopic examination showed moderate to severe bronchopneumonia associated to pyogenic bacterium. The isolation of A. pyogenes, the macro and microscopic lesions and the absence of BVDV an N. caninum antigen in the fetal tissues indicated the A. pyogenes as a causative agent of this fetal abortion

    Simulación de un enfriador híbrido alimentado por energía solar térmica

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    CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En este trabajo se presenta la modelación y simulación de un enfriador híbrido compresión/absorción alimentado por un concentrador solar de disco parabólico. El enfriamiento producido por este sistema se utiliza para aire acondicionado de una vivienda. El estudio fue realizado mediante balances de energía y de masa, en cada componente de los sistemas de refrigeración y del sistema solar. La transferencia de calor por convección y por radiación también fueron considerados. Los resultados muestran que la carga proporcionada por el sistema de compresión es 20% mayor que el alimentado por el sistema de absorción. Aunque el sistema de absorción opera al 40% de la carga total requerida en el espacio a condicionar, requiere en torno a 40% más energía térmica que el sistema de compresión. Pueden obtenerse temperaturas cercanas a 1050 °C y 400 °C con relación de concentración de 20 y radiación solar de 600W/m2 respectivamente. La eficiencia del colector solar es 0.4 (40%) cuando la temperatura exterior es 35 °C a baja radiación de 200 W/m2.RESUMO: This paper presents the modeling and simulation of a compression/absorption hybrid chiller driven by a solar dish collector. The cooling produced by this system is used for air conditioning in a home. The study was carried out using energy and mass balances in each component of the cooling systems and the solar system. Convection and radiation heat transfer were also considered. The results show that the load provided by the compression system is 20% greater than that fed by the absorption system. Although the absorption system operates at 40% of the total load required in the space to be conditioned, it requires around 40% more thermal energy than the compression system. Temperatures close to 1050 °C and 400 °C can be obtained in concentration ratio of 20 and solar radiation of 600W/m2 respectively. Efficiency of the solar collector is 0.4 (40%) when the outdoor temperature is 35 °C at a low radiation of 200 W/m2.info:eu-repo/semantics/publishedVersio

    Extracellular ATP released by osteoblasts is a key local inhibitor of bone mineralisation

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    Previous studies have shown that exogenous ATP (>1µM) prevents bone formation in vitro by blocking mineralisation of the collagenous matrix. This effect is thought to be mediated via both P2 receptor-dependent pathways and a receptor-independent mechanism (hydrolysis of ATP to produce the mineralisation inhibitor pyrophosphate, PPi). Osteoblasts are also known to release ATP constitutively. To determine whether this endogenous ATP might exert significant biological effects, bone-forming primary rat osteoblasts were cultured with 0.5-2.5U/ml apyrase (which sequentially hydrolyses ATP to ADP to AMP + 2Pi). Addition of 0.5U/ml apyrase to osteoblast culture medium degraded extracellular ATP to <1% of control levels within 2 minutes; continuous exposure to apyrase maintained this inhibition for up to 14 days. Apyrase treatment for the first 72 hours of culture caused small decreases (≤25%) in osteoblast number, suggesting a role for endogenous ATP in stimulating cell proliferation. Continuous apyrase treatment for 14 days (≥0.5U/ml) increased mineralisation of bone nodules by up to 3-fold. Increases in bone mineralisation were also seen when osteoblasts were cultured with the ATP release inhibitors, NEM and brefeldin A, as well as with P2X1 and P2X7 receptor antagonists. Apyrase decreased alkaline phosphatase (TNAP) activity by up to 60%, whilst increasing the activity of the PPi-generating ecto-nucleotide pyrophosphatase/phosphodiesterases (NPPs) up to 2.7-fold. Both collagen production and adipocyte formation were unaffected. These data suggest that nucleotides released by osteoblasts in bone could act locally, via multiple mechanisms, to limit mineralisation

    Aptitud de los alumnos de pregrado de la carrera de Medicina ante dos modelos de evaluación: El caso de Endocrinología.

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    Antecedentes: La Facultad de Medicina de la UANL inició en agosto del 2006 un nuevo plan de estudios y un modelo educativo basado en el aprendizaje y en la participación más intensa del alumno. Esta modificación en la estrategia de formar a los futuros médicos requiere ser evaluada científicamente con el propósito de medir si los cambios esperados con la implementación del plan de estudios y del modelo educativo, están ocurriendo. Objetivo: Comparar la aptitud de los alumnos del curso de pregrado de endocrinología ante dos métodos de evaluación. Método: Comparación de dos exámenes como proceso de evaluación ante dos planteamientos académicos: el actual (basado en la aplicación del conocimiento, casos clínicos) y el próximo anterior (basado en la memorización de conocimientos). Se contrastó la aptitud de los alumnos del nuevo plan de estudios (n = 74) vs. los alumnos del plan anterior (n = 137), ante el mismo examen. Resultados: Los alumnos del nuevo plan de estudios tuvieron una aptitud casi idéntica al ser evaluados con el examen actual y con el aplicado en ciclos anteriores (73.4 + 7.8 vs. 72.9 + 10.7, respectivamente) p = 0.2553. El porcentaje de aprobación fue de un 71 vs. 67%. Al comparar la aptitud de los alumnos del plan actual y el anterior ante un mismo examen, la aptitud fue muy favorable en el grupo de alumnos del nuevo plan de estudios (74.7 ± 10.7 vs. 56.0 ± 9.3), p< 0.0001. Conclusiones: La combinación de un modelo educativo centrado en el aprendizaje, en una acentuada participación del alumno en la clase, en una forma de evaluación que incentiva el estudiar la clase diaria y en la aplicación de exámenes dirigidos a evaluar la aplicación del conocimiento como en la vida real de un médico, son los aspectos que debemos fortalecer en el proceso de formación de nuestros futuros médicos

    Ovarian and Adrenal Androgens and Their Link to High Human Chorionic Gonadotropin Levels: A Prospective Controlled Study

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    Background. Although the association between human chorionic gonadotropin (hCG) and hyperandrogenism was identified more than 40 years ago, relevant questions remain unanswered. Design and Methods. We conducted a prospective, longitudinal, and controlled study in 23 women with a diagnosis of a complete hydatidiform mole (HM). Results. All participants completed the study. Before HM evacuation mean hCG was markedly higher in the cases than in the control group (P≤0.001). Free testosterone (T) and dehydroepiandrosterone sulfate (DHEA-S) were found to be higher in the cases (2.78 ± 1.24 pg/mL and 231.50 ± 127.20 μ/dL) when compared to the control group (1.50 ± 0.75 pg/mL and 133.59 ± 60.69 μ/dL) (P=0.0001 and 0.001), respectively. There was a strong correlation between hCG and free T/total T/DHEA-S concentrations (r=0.78; P≤0.001, r=0.74;  P≤0.001, and r=0.71;  P≤0.001), respectively. In the cases group 48 hours after HM evacuation, hCG levels were found to be significantly lower when compared to initial levels (P=0.001) and free T and DHEA-S declined significantly (P=0.0002 and 0.009). Conclusion. Before uterus evacuation, hCG, free T, and DHEA-S levels were significantly higher when compared with controls finding a strong correlation between hCG and free T/DHEA-S levels. Forty-eight hours after HM treatment hCG levels declined and the difference was lost. A novel finding of our study is that in cases, besides free T, DHEA-S was also found to be significantly higher and both the ovaries and adrenal glands appear to be the sites of this androgen overproduction

    Holographic flows in non-Abelian T-dual geometries

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    We use non-Abelian T-duality to construct new N=1 solutions of type IIA supergravity (and their M-theory lifts) that interpolate between AdS_5 geometries. We initiate a study of the holographic interpretation of these backgrounds as RG flows between conformal fixed points. Along the way we give an elegant formulation of non-Abelian T-duality when acting on a wide class of backgrounds, including those corresponding to such flows, in terms of their SU(2) structure

    Field theory aspects of non-Abelian T-duality and N = 2 linear quivers

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    In this paper we propose a linear quiver with gauge groups of increasing rank as field theory dual to the AdS 5 background constructed by Sfetsos and Thompson through non-Abelian T-duality. The formalism to study 4d N = 2 SUSY CFTs developed by Gaiotto and Maldacena is essential for our proposal. We point out an interesting relation between (Hopf) Abelian and non-Abelian T-dual backgrounds that allows to see both backgrounds as different limits of a solution constructed by Maldacena and Núñez. This suggests different completions of the long quiver describing the CFT dual to the nonAbelian T-dual background that match different observables

    BMN vacua, superstars and non-abelian T-duality

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    Acting with non-Abelian T-duality on the S3S^3 inside the AdS5AdS_5 subspace of AdS5×S5AdS_5\times S^5 with NN units of flux, we generate a new half-BPS solution with SU(24)SU(2|4) symmetry that belongs to the Lin-Lunin-Maldacena class of geometries. The analysis of the asymptotics, quantised charges and probe branes in this geometry suggests an interpretation as the gravity dual to the Berenstein-Maldacena-Nastase Plane Wave Matrix Model, in a particular vacuum associated to a partition of NN, in which the multiplicity of each SU(2)SU(2) irreducible representation is equal to its dimension. This vacuum is interpreted in M-theory in terms of giant gravitons backreacting in the maximally supersymmetric pp-wave geometry. Consistently with this, we show that the non-Abelian T-dual solution exactly agrees with the Penrose limit of the superstar solution in AdS7×S4AdS_7\times S^4. This suggests an interesting global completion of the non-Abelian T-dual solution in terms of an M5-brane geometry.Comment: 28 pages, discussion in section 5.1 improved, results unchanged, reference added. Matches published versio

    Recent Advances in Prodigiosin as a Bioactive Compound in Nanocomposite Applications

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    Bionanocomposites based on natural bioactive entities have gained importance due to their abundance; renewable and environmentally benign nature; and outstanding properties with applied perspective. Additionally, their formulation with biological molecules with antimicrobial, antioxidant, and anticancer activities has been produced nowadays. The present review details the state of the art and the importance of this pyrrolic compound produced by microorganisms, with interest towards Serratia marcescens, including production strategies at a laboratory level and scale-up to bioreactors. Promising results of its biological activity have been reported to date, and the advances and applications in bionanocomposites are the most recent strategy to potentiate and to obtain new carriers for the transport and controlled release of prodigiosin. Prodigiosin, a bioactive secondary metabolite, produced by Serratia marcescens, is an effective proapoptotic agent against bacterial and fungal strains as well as cancer cell lines. Furthermore, this molecule presents antioxidant activity, which makes it ideal for treating wounds and promoting the general improvement of the immune system. Likewise, some of the characteristics of prodigiosin, such as hydrophobicity, limit its use for medical and biotechnological applications; however, this can be overcome by using it as a component of a bionanocomposite. This review focuses on the chemistry and the structure of the bionanocomposites currently developed using biorenewable resources. Moreover, the work illuminates recent developments in pyrrole-based bionanocomposites, with special insight to its application in the medical area.This work was funded by CSIC-Tecnológico de Monterrey under i-Link+program (LINKB20030) for a project entitled “Contaminantes emergentes y prioritarios en las aguas reutilizadas en agricultura: riesgos y efectos en suelos, producción agrícola y entorno ambiental”.Peer reviewe
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