10,179 research outputs found

    One- and two-proton transfer reactions with vibrational Nuclei

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    We extend a semiclassical model of transfer reactions to the case in which one of the collision partners is a vibrational nucleus. The model is applied to one- and two-proton stripping reactions in the 37Cl + 98Mo system, for which a rapid transition from normal to anomalous slope in the two proton transfer reaction at energies around the Coulomb barrier is experimentally observed. This behavior is satisfactorily reproduced by the present extension of the model.Comment: LaTeX, 10 pages, 1 figure (PostScript

    Pelaksanaan E-government di Kantor Imigrasi Kelas Ia Kota Pekanbaru Tahun 2014

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    Development of E-Government is an attempt to develop the implementation of governance through the use of electronic media to improve the quality of public services. The purpose electronic government is to improve citizens' access to public services, government services, increasing access to sources of information held by the government, to handle public complaints and service quality equation that can be enjoyed by all citizens. The use of information systems for the purpose so that the service could be faster, but not all people know the existence of such passport information system. People who are or will make a passport, passport information system to use it. The purpose of this study was to analyze the implementation of E-Government in the passport at the Immigration Office of Pekanbaru. In this study, the concept used refers to the Electronic Government or the E-Government. This study uses descriptive study using a qualitative method approach. In the data collection researchers use interviewing techniques and documentation. The results of this study can be concluded that the implementation of E-Government in the passport at the Immigration Office Class IA Pekanbaru City has not been done well it turned out for a passport online just for formality data only applicant community still fill your data manually at the Immigration Office. For that is expected. The need for data updated regularly on the website of the Immigration Office Class IA Pekanbaru City so there is something new going on, so many attract people to access it. because such reforms are indispensable additions website operator to be fast in responding to any complaints society in the process of interaction

    Usos formales y no formales de las TIC entre los estudiantes universitarios

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    La presente comunicación muestra los resultados de una investigación que tiene por finalidad identificar y comprender los usos de las TIC por parte de estudiantes universitarios en sus procesos de aprendizaje, con la intención de extraer conclusiones que permitan mejorar el diseño de las situaciones de aprendizaje en contextos formales, haciéndolas más próximas, adaptadas y motivadoras para éstos, teniendo en cuenta los diferentes perfiles de estudiantes identificados y aprovechando la identificación y uso que estos muestran por determinados recursos tecnológicos

    Peripheral and central mechanisms involved in hormonal control of male and female reproduction

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    Reproduction involves the integration of hormonal signals acting across multiple systems togenerate a synchronized physiological output. A critical component of reproduction is the luteinizinghormone (LH) surge, which is mediated by estradiol (E2) and neuroprogesterone interacting tostimulate kisspeptin release in the rostral periventricular nucleus of the third ventricle in rats. Recentevidence has shown that both classical and membrane E2 and progesterone signaling is involved inthis pathway. A metabolite of gonadotropin-releasing hormone (GnRH), GnRH-(1-5), has been shownto stimulate GnRH expression, secretion, and has a role in the regulation of lordosis. Additionally,gonadotropin-inhibitory hormone (GnIH) projects to and influences the activity of GnRH neurons inbirds. Stress-induced changes in GnIH have been shown to alter breeding behaviors in birds,demonstrating another molecular control of reproduction. Peripherally, paracrine and autocrineactions within the gonad have been suggested as therapeutic targets for infertility in both males andfemales. Dysfunction of testicular prostaglandin synthesis is a possible cause of idiopathic maleinfertility. Indeed, local production of melatonin and corticotropin-releasing hormone (CRH) couldinfluence spermatogenesis via immune pathways in the gonad. In females, vascular endothelialgrowth factor A (VEGF-A) has been implicated in an angiogenic process that mediates developmentof the corpus luteum and thus fertility via the Notch signaling pathway. Age-induced decreases infertility involve ovarian kisspeptin and its regulation of ovarian sympathetic innervation. Finally,morphological changes in the arcuate nucleus of the hypothalamus influence female sexualreceptivity in rats. The processes mediating these morphological changes have been shown toinvolve rapid effects of E2 controlling synaptogenesis in this hypothalamic nucleus. Together, thisreview highlights new research in these areas, focusing on recent findings in the molecularmechanisms of central and peripheral hormonal control of reproduction.Fil: Rudolph, L. M.. University of California at Los Angeles; Estados UnidosFil: Bentley, G. E.. University of California Berkeley; Estados UnidosFil: Calandra, Ricardo Saul. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Paredes, A. H.. Universidad de Chile; ChileFil: Tesone, Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wu, T. J.. Uniformed Services University; Estados UnidosFil: Micevych, P. E.. University of California at Los Angeles; Estados Unido

    Superando el concepto de nativo digital. Análisis de las prácticas digitales del estudiantado universitario

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    A lo largo de la última década, niños y jóvenes han sido etiquetados como nativos digitales. Se considera que cualquier persona nacida a partir de la década de los 80 es hablante nativo de una lengua digital basada en el uso de los ordenadores, los videojuegos e Internet. De todos modos, algunos autores cuestionan este concepto ¿se trata realmente de jóvenes que aprenden de modo distinto, o simplemente incorporan algunas herramientas y procedimientos nuevos a su forma de acceder a la información y socializarse? El artículo presenta los resultados de una investigación (Usos de las TIC entre los estudiantes universitarios: perspectiva académica y social de los procesos de aprendizaje mediados. EDU2009-12125) centrada en el uso de las TIC que hacen los jóvenes universitarios de las diferentes universidades de Cataluña. Los resultados revelan distintos usos de las tecnologías, diferenciados por los ámbitos de uso y se alinean en las visiones críticas del concepto de nativo digital. La relevancia de los resultados apuntan a lineas emergentes de investigación para seguir mejorando la educación superior

    A conjectured scenario for order-parameter fluctuations in spin glasses

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    We study order-parameter fluctuations (OPF) in disordered systems by considering the behavior of some recently introduced paramaters G,GcG,G_c which have proven very useful to locate phase transitions. We prove that both parameters G (for disconnected overlap disorder averages) and GcG_c (for connected disorder averages) take the respective universal values 1/3 and 13/31 in the T0T\to 0 limit for any {\em finite} volume provided the ground state is {\em unique} and there is no gap in the ground state local-field distributions, conditions which are met in generic spin-glass models with continuous couplings and no gap at zero coupling. This makes G,GcG,G_c ideal parameters to locate phase transitions in disordered systems much alike the Binder cumulant is for ordered systems. We check our results by exactly computing OPF in a simple example of uncoupled spins in the presence of random fields and the one-dimensional Ising spin glass. At finite temperatures, we discuss in which conditions the value 1/3 for G may be recovered by conjecturing different scenarios depending on whether OPF are finite or vanish in the infinite-volume limit. In particular, we discuss replica equivalence and its natural consequence limVG(V,T)=1/3\lim_{V\to\infty}G(V,T)=1/3 when OPF are finite. As an example of a model where OPF vanish and replica equivalence does not give information about G we study the Sherrington-Kirkpatrick spherical spin-glass model by doing numerical simulations for small sizes. Again we find results compatible with G=1/3 in the spin-glass phase.Comment: 18 pages, 9 postscript figure

    Analysis and agrometeorological modelling of grapevine responses to different trellising systems

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    As the greater part of current viticulture is based on traditional trellising systems, usually in single hedgewall training, the aim of this research is to evaluate the possibility of introducing alternative trellising systems in order to improve canopy architecture and leaf distribution, and optimize light interception. In 2001 and 2002 field measurements (agrometeorological variables, vegetative growth, productivity and physiological behaviour) and modeling were performed on Sangiovese grapevines in a Tuscan vineyard with two trellis systems: a single hedgewall and a low double hedgewall (lyre trellis). The vines were spur pruned and cordon trained and the planting density was 6,667 vines/hectare. The two trellising systems were distributed in a randomized block design with 4 replications of 3 rows each. Data were collected from the central row. The simulation was obtained using a model, implemented with the Stella language, consisting of three sub-modules concerning photosynthesis, respiration and biomass accumulation. Light interception was greater for the lyre system than for the single cordon, while no differences were obtained in single leaf photosynthesis measurements between the trellis systems. Vegetative growth was higher for the lyre, indicating that lyre had a higher whole plant photosynthesis. The lyre system had greater yield due to a higher cluster number and a higher cluster weight compared to the single cordon training. No differences in must sugar content, titratable acidity or anthocyanins were observed. Models satisfactorily simulate the growth of grapevine under the single cordon system, while the growth of the lyre vine was extremely underestimated.

    Compact massive objects in Virgo galaxies: the black hole population

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    We investigate the distribution of massive black holes (MBHs) in the Virgo cluster. Observations suggest that AGN activity is widespread in massive galaxies (M>1e10 solar masses), while at lower galaxy masses star clusters are more abundant, which might imply a limited presence of central black holes in these galaxy-mass regimes. We explore if this possible threshold in MBH hosting, is linked to nature, nurture, or a mixture of both. The nature scenario arises naturally in hierarchical cosmologies, as MBH formation mechanisms typically are efficient in biased systems, which would later evolve into massive galaxies. Nurture, in the guise of MBH ejections following MBH mergers, provides an additional mechanism that is more effective for low mass, satellite galaxies. The combination of inefficient formation, and lower retention of MBHs, leads to the natural explanation of the distribution of compact massive ob jects in Virgo galaxies. If MBHs arrive to the correlation with the host mass and velocity dispersion during merger-triggered accretion episodes, sustained tidal stripping of the host galaxies creates a population of MBHs which lie above the expected scaling between the holes and their host mass, suggesting a possible environmental dependence.Comment: MNRAS letter

    Effect of Energetic Supplementation on Forage Losses in an Oat and Italian Ryegrass Pasture under Continuous Grazing

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    The experiment was conducted at UFSM-RS to quantify herbage losses in oat and Italian ryegrass mixture under continuous grazing by beef heifers. A continuous grazing method with variable stocking rate was utilized to maintain the same herbage mass, 1500 kg DM/ha, in all treatments. The treatments consisted of levels of energetic supplement (0, 0.7 and 1.4% of LW/day). The pasture was evaluated every 28 days, when forage not suitable for grazing was collected in points previously marked in experimental area. The daily losses of herbage mass were of 22.32, 18.98 and 21.16 kg of DM/ha/day, equivalent to 2.61, 1.91 and 1.41% of LW for levels of 0, 0.7 and 1.4% of LW/day, respectively. The results showed greater stocking rates in supplemented treatments, being 21.2% and 57.4% higher in 0.7 and 1.4% LW/day, respectively, than unsupplemented one

    Dynamics and Production of Forage in Winter Pasture under Continuous Grazing with Energetic Supplementation

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    This experiment was carried out at Federal University of Santa Maria, from July 09 to November 12, 1999 to evaluate the dynamics and production of forage of oat (Avena strigosa Schreb) and italian ryegrass (Lolium multiflorum Lam) mixture. The grazing system used was continuous with variable stocking rate to maintain 1500kg/ha of herbage mass in all treatments. The heifers were subjected to different levels of energetic supplementation. They are 0, 0.7 and 1.4% of LW/day. The pasture of oat and italian ryegrass presented an accumulation rate of 45.7, 55.1 and 50.0 kg of DM/ha /day and a total dry matter (DM) production of 7067, 7222 and 8137 kg/ha for 0, 0.7 and 1.4% of LW/day levels, respectively. The average percentage of leaf component was 8.26, 11.48 and 11.72 for oat and 23.12, 22.35 and 20.93 for Italian ryegrass at 0, 0.7 and 1.4% of LW/day levels, respectively. The supplementation neither affected the accumulation rate nor the total DM production of the pasture (P\u3e 0.05). The senescent material was lower (P\u3c 0.05) with no supplementation
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