484 research outputs found
Selective inhibition of Rous sarcoma virus production in transformed chick fibroblasts by two rifamycin derivatives
Some consequences of a spatially varying cosmological constant in a spherically symmetric distribution of matter
This paper investigates the effects of the spatial variation of the cosmological constant Λ on the spacetime geometry within and outside a massive object. It is seen that the variation of Λ with the radial coordinate introduces non-trivial changes leading to spacetime closing on itself around a massive object. It may also be possible to generate interior solutions that lead to flat rotation curves of galaxies
Positional cloning of the PIS mutation in goats and its impact on understanding mammalian sex-differentiation
In goats, the PIS (polled intersex syndrome) mutation is responsible for both the absence of horns in males and females and sex-reversal affecting exclusively XX individuals. The mode of inheritance is dominant for the polled trait and recessive for sex-reversal. In XX PIS-/- mutants, the expression of testis-specific genes is observed very precociously during gonad development. Nevertheless, a delay of 4–5 days is observed in comparison with normal testis differentiation in XY males. By positional cloning, we demonstrate that the PIS mutation is an 11.7-kb regulatory-deletion affecting the expression of two genes, PISRT1 and FOXL2 which could act synergistically to promote ovarian differentiation. The transcriptional extinction of these two genes leads, very early, to testis-formation in XX homozygous PIS-/- mutants. According to their expression profiles and bibliographic data, we propose that FOXL2 may be an ovary-differentiating gene, and the non-coding RNA PISRT1, an anti-testis factor repressing SOX9, a key regulator of testis differentiation. Under this hypothesis, SRY, the testis-determining factor would inhibit these two genes in the gonads of XY males, to ensure testis differentiation
Time on a Rotating Platform
Traditional clock synchronisation on a rotating platform is shown to be
incompatible with the experimentally established transformation of time. The
latter transformation leads directly to solve this problem through noninvariant
one-way speed of light. The conventionality of some features of relativity
theory allows full compatibility with existing experimental evidence.Comment: 12 pages, Latex, no figure. Copies available at [email protected]
accepted for publication in Found. Phys. Let
Definition of a crowdsourcing innovation service for the european SMEs
Based on literature review and on the study of the most known and referred Crowdsourcing brokers, there's a clear trend to implement this model by large companies and mainly within the North American context. Our research team is focused in bringing this approach closer to the European culture, more specifically the cultural factors underlying the dynamics and motivation of communities available to solve the innovation challenges of Small and Medium Enterprises (SMEs), that we call Crowdsourcing Innovation. We believe that, due to the common lack of resources for innovation in these companies, a service capable of involving them in large networks filled with useful and reachable knowledge, and capable of supporting these companies through all the innovation process, is crucial to the future competitiveness of the European SMEs. Although our team is focusing on several aspects related to Crowdsourcing, my main research focuses the information services and supporting applications to create a web platform adapted to the key economical, organizational, legal and cultural differences that make current Crowdsourcing Innovation businesses less popular among European SMEs than in North America.- (undefined
Time-like flows of energy-momentum and particle trajectories for the Klein-Gordon equation
The Klein-Gordon equation is interpreted in the de Broglie-Bohm manner as a
single-particle relativistic quantum mechanical equation that defines unique
time-like particle trajectories. The particle trajectories are determined by
the conserved flow of the intrinsic energy density which can be derived from
the specification of the Klein-Gordon energy-momentum tensor in an
Einstein-Riemann space. The approach is illustrated by application to the
simple single-particle phenomena associated with square potentials.Comment: 14 pages, 11 figure
Jamming non-local quantum correlations
We present a possible scheme to tamper with non-local quantum correlations in
a way that is consistent with relativistic causality, but goes beyond quantum
mechanics. A non-local ``jamming" mechanism, operating within a certain
space-time window, would not violate relativistic causality and would not lead
to contradictory causal loops. The results presented in this Letter do not
depend on any model of how quantum correlations arise and apply to any jamming
mechanism.Comment: 10 pp, LaTe
Los programas de financiamiento a MiPyMEs y el desarrollo territorial de Argentina
Small and Medium Enterprises (SMEs) have difficulties in accessing external finance and this is an important restriction to the growth of this type of firms. The government as a provider of public policies, mitigate these limitations. Although there are many papers that evaluate the impact of public policies on the performance of SMEs, the objective of this paper is to analyse the effect of these policies in relation to their territorial distribution. For this purpose, incidence, location and distribution indicators are presented, and they are applied to a subsidized credit bank called Productive Force Program for the period 2008-2013 in the Province of Buenos Aires, Argentine. The results show that the PFP promotes territorial equity, while there are deconcentrating results in all de the indicators.Las dificultades de las Micro, Pequeñas y Mediana Empresas (MiPyMEs) para acceder al financiamiento externo son una limitación importante en el crecimiento de este sector. El Estado, a través de las Políticas Públicas, intenta morigerar dichas limitaciones. Si bien existen trabajos que evalúan el impacto de las políticas públicas sobre el desempeño de las empresas, el objetivo de este trabajo es analizar la incidencia de dichas políticas en relación a su distribución territorial. Para ello, se plantean una serie de indicadores de concentración, localización y distribución, y se aplican a un programa de financiamiento denominado Programa Fuerza Productiva (PFP) para el período 2008-2013 en la Provincia de Buenos Aires, Argentina. Los resultados muestran que el PFP mejora la equidad territorial, en tanto se encuentran resultados desconcentradores en todos los indicadores utilizados
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