Non Singular Origin of the Universe and its Present Vacuum Energy Density

We consider a non singular origin for the Universe starting from an Einstein static Universe, the so called "emergent universe" scenario, in the framework of a theory which uses two volume elements $\sqrt{-{g}}d^{4}x$ and $\Phi d^{4}x$, where $\Phi$ is a metric independent density, used as an additional measure of integration. Also curvature, curvature square terms and for scale invariance a dilaton field $\phi$ are considered in the action. The first order formalism is applied. The integration of the equations of motion associated with the new measure gives rise to the spontaneous symmetry breaking (S.S.B) of scale invariance (S.I.). After S.S.B. of S.I., it is found that a non trivial potential for the dilaton is generated. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting effective potential for the dilaton contains two flat regions, for $\phi \rightarrow \infty$ relevant for the non singular origin of the Universe, followed by an inflationary phase and $\phi \rightarrow -\infty$, describing our present Universe. The dynamics of the scalar field becomes non linear and these non linearities are instrumental in the stability of some of the emergent universe solutions, which exists for a parameter range of values of the vacuum energy in $\phi \rightarrow -\infty$, which must be positive but not very big, avoiding the extreme fine tuning required to keep the vacuum energy density of the present universe small. Zero vacuum energy density for the present universe defines the threshold for the creation of the universe.Comment: 28 pages, short version of this paper awarded an honorable mention by the Gravity Research Foundation, 2011, accepted for publication in International Journal of Modern Physics

Sensor electroquímic de clor per a aigües potables

El lleixiu, amb el clor que conté, és necessari per a desinfectar l'aigua que prenem, però en dosis elevades podria intoxicar-nos. Per això, és important que les eines que detecten la quantitat de clor en l'aigua siguin fiables. Investigadors del Centre Nacional de Microelectrónica han creat un xip que permet verificar amb exactitud i de manera continuada la quantitat de clor en l'aigua

The action of the sex linked barring gene on Spanish chickens with gold plumage

International audienc

Oikos nomos Vs. oikos logos? Towards the alliance between business management and environmental sustainability

Environmental sustainability is a topic that is increasingly becoming popular and companies are not excluded from this phenomenon. On the contrary, their responsibility towards environment is increasingly in the public eye, so that the same companies pay more and more attention to communicating their commitment to all stakeholders in order to improve their image and reputation. Furthermore, from a scientific point of view, a growing array of studies also investigates how to measure sustainability with the aim of defining more accurate indicators of the environmental impact generated by companies. This work has a threefold objective: 1) highlighting firstly the compatibility between the companies’ activities and green strategies through the analysis of those studies that demonstrate the benefits of implementing eco-sustainable practices; 2) describing the approach actually implemented by the companies; 3) description of the phenomenon of greenwashing that is a kind of communication through which some companies try to appear eco-sustainable, even though they are not.. In the final part of the work some cases of greenwashing are exposed, specifying the negative consequences they have sparked. The relationship between ecology and economics is, indeed, not contrasting but, on the contrary, strongly symbiotic, from the etymological origin of the two terms to the positive effects produced by green strategies, as demonstrated by many studies in literature

Papillomavirus E5: the smallest oncoprotein with many functions

Papillomaviruses (PVs) are established agents of human and animal cancers. They infect cutaneous and mucous epithelia. High Risk (HR) Human PVs (HPVs) are consistently associated with cancer of the uterine cervix, but are also involved in the etiopathogenesis of other cancer types. The early oncoproteins of PVs: E5, E6 and E7 are known to contribute to tumour progression. While the oncogenic activities of E6 and E7 are well characterised, the role of E5 is still rather nebulous. The widespread causal association of PVs with cancer makes their study worthwhile not only in humans but also in animal model systems. The Bovine PV (BPV) system has been the most useful animal model in understanding the oncogenic potential of PVs due to the pivotal role of its E5 oncoprotein in cell transformation. This review will highlight the differences between HPV-16 E5 (16E5) and E5 from other PVs, primarily from BPV. It will discuss the targeting of E5 as a possible therapeutic agent

Land-atmosphere interactions in an high resolution atmospheric simulation coupled with a surface data assimilation scheme

A valid tool for the retrieving of the turbulent fluxes that characterize the surface energy budget is constituted by the remote sensing of land surface states. In this study sequences of satellite-derived observations (from SEVIRI sensors aboard the Meteosat Second Generation) of Land Surface Temperature have been used as input in a data assimilation scheme in order to retrieve parameters that describe energy balance at the ground surface in the Tuscany region, in central Italy, during summer 2005. A parsimonious 1-D multiscale variational assimilation procedure has been followed, that requires also near surface meteorological observations. A simplified model of the surface energy balance that includes such assimilation scheme has been coupled with the limited area atmospheric model RAMS, in order to improve in the latter the accuracy of the energy budget at the surface. The coupling has been realized replacing the assimilation scheme products, in terms of surface turbulent fluxes and temperature and humidity states during the meteorological simulation. Comparisons between meteorological model results with and without coupling with the assimilation scheme are discussed, both in terms of reconstruction of surface variables and of vertical characterization of the lower atmosphere. In particular, the effects of the coupling on the moisture feedback between surface and atmosphere are considered and estimates of the precipitation recycling ratio are provided. The results of the coupling experiment showed improvements in the reconstruction of the surface states by the atmospheric model and considerable influence on the atmospheric dynamics