3,844 research outputs found

    Efecto indirecto del uso de la banda ancha en el emprendimiento : un enfoque basado en los recursos del individuo

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    Se busca contribuir a al conocimiento sobre la influencia de las tecnolog?as de la informaci?n y comunicaci?n (TIC) en la actividad emprendedora de los pa?ses. Para este fin, se revisar? en ellos el efecto indirecto del uso de la banda ancha en el emprendimiento de individuos dados sus recursos de capital humano y social. Para la validaci?n emp?rica, se propone un modelo multinivel que usar? datos del reporte del Monitor Global de Emprendimiento (GEM) y de aquel de la Uni?n Internacional de Telecomunicaciones (ITU). Son considerados para la muestra pa?ses en v?as de desarrollo de Latinoam?rica. Se espera encontrar un mayor efecto indirecto del uso de la banda ancha m?vil en comparaci?n a la banda ancha fija. Asimismo, las conclusiones de este estudio podr?an ayudar a quienes definan pol?ticas enfocadas en la promoci?n de la actividad emprendedora

    Leading-effect vs. Risk-taking in Dynamic Tournaments: Evidence from a Real-life Randomized Experiment

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    Two 'order effects' may emerge in dynamic tournaments with information feedback. First, participants adjust effort across stages, which could advantage the leading participant who faces a larger 'effective prize' after an initial victory (leading-effect). Second, participants lagging behind may increase risk at the final stage as they have 'nothing to lose' (risk-taking). We use a randomized natural experiment in professional two-game soccer tournaments where the treatment (order of a stage-specific advantage) and team characteristics, e.g. ability, are independent. We develop an identification strategy to test for leading-effects controlling for risk-taking. We find no evidence of leading-effects and negligible risk-taking effects

    Increased RPA1 gene dosage affects genomic stability potentially contributing to 17p13.3 duplication syndrome

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    A novel microduplication syndrome involving various-sized contiguous duplications in 17p13.3 has recently been described, suggesting that increased copy number of genes in 17p13.3, particularly PAFAH1B1, is associated with clinical features including facial dysmorphism, developmental delay, and autism spectrum disorder. We have previously shown that patient-derived cell lines from individuals with haploinsufficiency of RPA1, a gene within 17p13.3, exhibit an impaired ATR-dependent DNA damage response (DDR). Here, we show that cell lines from patients with duplications specifically incorporating RPA1 exhibit a different although characteristic spectrum of DDR defects including abnormal S phase distribution, attenuated DNA double strand break (DSB)-induced RAD51 chromatin retention, elevated genomic instability, and increased sensitivity to DNA damaging agents. Using controlled conditional over-expression of RPA1 in a human model cell system, we also see attenuated DSB-induced RAD51 chromatin retention. Furthermore, we find that transient over-expression of RPA1 can impact on homologous recombination (HR) pathways following DSB formation, favouring engagement in aberrant forms of recombination and repair. Our data identifies unanticipated defects in the DDR associated with duplications in 17p13.3 in humans involving modest RPA1 over-expression

    Plan de negocio para la viabilidad comercial, operativa y econ?mica en la implementaci?n de un gimnasio para bebes de 4 meses a ni?os de 5 a?os, en Lima Norte

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    La obesidad en los ni?os representa un problema a largo plazo, afectando su salud al incrementarse el riesgo de padecer enfermedades cardiovasculares o diabetes; se recomienda desde la etapa infantil, una correcta alimentaci?n y una actividad f?sica frecuente, desarrollando h?bitos saludables. En ese sentido, la siguiente propuesta es un plan de negocio para implementar un gimnasio para bebes de 4 meses a 5 a?os en Lima Norte, considerando la importante tasa de crecimiento en este sector de la poblaci?n, determinando como mercado objetivo madres de los NSE B y C, de los distritos de Comas, San Mart?n de Porres, Los Olivos e Independencia. Del estudio de mercado se ha identificado una demanda potencial de servicios que contribuyan al desarrollo infantil y no se conocen gimnasios para ni?os menores de 5 a?os. La propuesta de valor del gimnasio Baby Gym es ofrecer el servicio de gimnasio para a trav?s de un ambiente l?dico se fortalezcan habilidades al propio ritmo de cada ni?o. Con una inversi?n inicial estimada de S/. 164,100.00 y un periodo de an?lisis de 10 a?os, se obtiene un VAN = S/. 96,977 y TIR de 29.3% respectivamente, con lo cual, el an?lisis financiero concluye que el negocio es viable

    On the warp drive space-time

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    In this paper the problem of the quantum stability of the two-dimensional warp drive spacetime moving with an apparent faster than light velocity is considered. We regard as a maximum extension beyond the event horizon of that spacetime its embedding in a three-dimensional Minkowskian space with the topology of the corresponding Misner space. It is obtained that the interior of the spaceship bubble becomes then a multiply connected nonchronal region with closed timelike curves and that the most natural vacuum allows quantum fluctuations which do not induce any divergent behaviour of the re-normalized stress-energy tensor, even on the event (Cauchy) chronology horizon. In such a case, the horizon encloses closed timelike curves only at scales close to the Planck length, so that the warp drive satisfies the Ford's negative energy-time inequality. Also found is a connection between the superluminal two-dimensional warp drive space and two-dimensional gravitational kinks. This connection allows us to generalize the considered Alcubierre metric to a standard, nonstatic metric which is only describable on two different coordinate patchesComment: 7 pages, minor comment on chronology protection added, RevTex, to appear in Phys. Rev.

    Identification of a novel synthetic lethal vulnerability in non-small cell lung cancer by co-targeting TMPRSS4 and DDR1

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    Finding novel targets in non-small cell lung cancer (NSCLC) is highly needed and identification of synthetic lethality between two genes is a new approach to target NSCLC. We previously found that TMPRSS4 promotes NSCLC growth and constitutes a prognostic biomarker. Here, through large-scale analyses across 5 public databases we identified consistent co-expression between TMPRSS4 and DDR1. Similar to TMPRSS4, DDR1 promoter was hypomethylated in NSCLC in 3 independent cohorts and hypomethylation was an independent prognostic factor of disease-free survival. Treatment with 5-azacitidine increased DDR1 levels in cell lines, suggesting an epigenetic regulation. Cells lacking TMPRSS4 were highly sensitive to the cytotoxic effect of the DDR1 inhibitor dasatinib. TMPRSS4/DDR1 double knock-down (KD) cells, but not single KD cells suffered a G0/G1 cell cycle arrest with loss of E2F1 and cyclins A and B, increased p21 levels and a larger number of cells in apoptosis. Moreover, double KD cells were highly sensitized to cisplatin, which caused massive apoptosis (~40%). In vivo studies demonstrated tumor regression in double KD-injected mice. In conclusion, we have identified a novel vulnerability in NSCLC resulting from a synthetic lethal interaction between DDR1 and TMPRSS4

    Altered pathways in methylome and transcriptome longitudinal analysis of normal weight and bariatric surgery women

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    DNA methylation could provide a link between environmental, genetic factors and weight control and can modify gene expression pattern. This study aimed to identify genes, which are differentially expressed and methylated depending on adiposity state by evaluating normal weight women and obese women before and after bariatric surgery (BS). We enrolled 24 normal weight (BMI: 22.5 +/- 1.6 kg/m(2)) and 24 obese women (BMI: 43.3 +/- 5.7 kg/m(2)) submitted to BS. Genome-wide methylation analysis was conducted using Infinium Human Methylation 450 BeadChip (threshold for significant CpG sites based on delta methylation level with a minimum value of 5%, a false discovery rate correction (FDR) of q /=2.0 was used to detect differentially expressed probes). The integrative analysis of both array data identified four genes (i.e. TPP2, PSMG6, ARL6IP1 and FAM49B) with higher methylation and lower expression level in pre-surgery women compared to normal weight women: and two genes (i.e. ZFP36L1 and USP32) that were differentially methylated after BS. These methylation changes were in promoter region and gene body. All genes are related to MAPK cascade, NIK/NF-kappaB signaling, cellular response to insulin stimulus, proteolysis and others. Integrating analysis of DNA methylation and gene expression evidenced that there is a set of genes relevant to obesity that changed after BS. A gene ontology analysis showed that these genes were enriched in biological functions related to adipogenesis, orexigenic, oxidative stress and insulin metabolism pathways. Also, our results suggest that although methylation plays a role in gene silencing, the majority of effects were not correlated

    Recent developments of the Hierarchical Reference Theory of Fluids and its relation to the Renormalization Group

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    The Hierarchical Reference Theory (HRT) of fluids is a general framework for the description of phase transitions in microscopic models of classical and quantum statistical physics. The foundations of HRT are briefly reviewed in a self-consistent formulation which includes both the original sharp cut-off procedure and the smooth cut-off implementation, which has been recently investigated. The critical properties of HRT are summarized, together with the behavior of the theory at first order phase transitions. However, the emphasis of this presentation is on the close relationship between HRT and non perturbative renormalization group methods, as well as on recent generalizations of HRT to microscopic models of interest in soft matter and quantum many body physics.Comment: 17 pages, 5 figures. Review paper to appear in Molecular Physic

    A global perspective on marine photosynthetic picoeukaryote community structure

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    A central goal in ecology is to understand the factors affecting the temporal dynamics and spatial distribution of microorganisms and the underlying processes causing differences in community structure and composition. However, little is known in this respect for photosynthetic picoeukaryotes (PPEs), algae that are now recognised as major players in marine CO2 fixation. Here, we analysed dot blot hybridisation and cloning–sequencing data, using the plastid-encoded 16S rRNA gene, from seven research cruises that encompassed all four ocean biomes. We provide insights into global abundance, α- and β-diversity distribution and the environmental factors shaping PPE community structure and composition. At the class level, the most commonly encountered PPEs were Prymnesiophyceae and Chrysophyceae. These taxa displayed complementary distribution patterns, with peak abundances of Prymnesiophyceae and Chrysophyceae in waters of high (25:1) or low (12:1) nitrogen:phosphorus (N:P) ratio, respectively. Significant differences in phylogenetic composition of PPEs were demonstrated for higher taxonomic levels between ocean basins, using Unifrac analyses of clone library sequence data. Differences in composition were generally greater between basins (interbasins) than within a basin (intrabasin). These differences were primarily linked to taxonomic variation in the composition of Prymnesiophyceae and Prasinophyceae whereas Chrysophyceae were phylogenetically similar in all libraries. These data provide better knowledge of PPE community structure across the world ocean and are crucial in assessing their evolution and contribution to CO2 fixation, especially in the context of global climate change
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