Primordial Density Fluctuations in a Dual Supergravity Cosmology

We analyse the spectrum of energy density fluctuations of a dual supergravity model where the dilaton and the moduli are stabilized and sucessful inflation is achieved inside domain walls that separate different vacua of the theory. Constraints on the parameters of the superpotential are derived from the amplitude of the primordial energy density fluctuations as inferred from COBE and it is shown that the scale dependence of the tensor perturbations nearly vanishes.Comment: 13 pages, Latex, 3 figures (uses epsf.sty

Análise de uma política pública de trânsito : a Balada Segura

O presente estudo vai verificar a eficácia da política pública Balada Segura nesses oito anos de atividade no Rio Grande do Sul. A Balada Segura atua, principalmente, nas noites e madrugadas, realizando blitze de fiscalização e educação para combater a alcoolemia no trânsito. Os motoristas abordados são submetidos ao teste do bafômetro. O programa começou em 2011 em Porto Alegre e já conta com 33 municípios engajados na causa, através de convênio com o Estado. Sobre a análise da política pública, a metodologia e a forma de abordagem utilizadas foram por estudo quantitativo que utilizou dados estatísticos para medir e verificar resultados. A coleta de dados foi através de pesquisa documental, utilizando dados secundários e documentos oficiais do DetranRS e da Balada Segura. Os resultados do estudo foram considerados satisfatórios, pois a política pública que este trabalho analisou é eficácia, ajuda a reduzir o índice de pessoas dirigindo sob o efeito de álcool e mostra que ajuda a diminuir a mortalidade no trânsito. Além disso, o aumento nas abordagens, nas autuações por alcoolemia no trânsito e aumento na fiscalização colabora para a segurança no trânsito.The present study will verify the effectiveness of the public policy Balada Segura in these eight years of activity in Rio Grande do Sul. The Balada Segura acts, mainly, in the nights and dawns, carrying out blitze of control and education to combat the traffic bacillemia. The drivers approached are submitted to the breathalyzer test. The program began in 2011 in Porto Alegre and already has 33 municipalities engaged in the cause, through an agreement with the State. On the public policy analysis, the methodology and the form of approach used were by quantitative study that used statistical data to measure and verify results. The data collection was through documentary research, using secondary data and official documents of the DetranRS and the Balada Segura. The results of the study were considered satisfactory, since the public policy that this work analyzed is efficacious, it helps to reduce the number of people driving under the influence of alcohol and shows that it helps to reduce the mortality in the traffic. In addition, the increase in approaches, in the assessments by blood alcohol in the traffic and increase in the control collaborates for the safety in the transit

A null biogeographic test for assessing ecological niche evolution

AIMS: Quantification of the degree to which ecological niches change over evolutionary timescales is important for deepening our understanding of evolutionary and ecological processes. Phylogenetic niche conservatism (PNC) is when closely related species differ less ecologically than expected by chance, whereas Phylogenetic Niche Divergence (PND) is when closely related species differ more ecologically than expected by chance. We present a new null model to test for PNC and PND (the RTR significance test), which we combine with a novel metric for quantifying niche overlap LOCATION: Europe, North America and Madagascar. METHODS: The RTR null model comprises many thousands of replicates generated by randomly translocating and rotating the set of occurrence records for two populations (e.g.,sister species) while maintaining the spatial configuration between all occurrences within each replicate. For each replicate we calculate niche overlap as the proportion of the combined niche breadth that is shared by the two species, averaged over n environmental dimensions. This approach enables us to test whether the observed niche overlap is more or less than expected by chance given the environmental conditions present in the study area. We test the performance of our approach in comparison to other methods using both simulated and real case scenarios, including crested newts in Europe, pocket gophers in North America, and lemurs in Madagascar. RESULTS: We find that our measure of niche overlap performs better than other metrics in an artificial simulation scenario, and we find evidence for both PNC and PND in our case studies for Europe, North America and Madagascar. Our results demonstrate that both the RTR significance test and the novel metric of niche overlap are consistent with evolutionary theory and are suitable methods to test for PNC and PND. MAIN CONCLUSIONS: We make available scripts to implement the RTR test and metric of niche overlap, and expect that the methods will prove useful for addressing a broad set of questions relating to ecological niche evolution and speciation, particularly for restricted-range species for which few known occurrence records are available

Enhanced fano resonance of organic material films deposited on arrays of asymmetric split-ring resonators (A-SRRs)

Depositing very thin organic films on the surface of arrays of asymmetric split-ring resonators (A-SRRs) produces a shift in their resonance spectra that can be utilized for sensitive analyte detection. Here we show that when poly-methyl-methacrylate (PMMA) is used as an organic probe (analyte) on top of the A-SRR array, the phase and amplitude of a characteristic molecular Fano resonance associated with a carbonyl bond changes according to the spectral positions of the trapped mode resonance of the A-SRRs and their plasmonic reflection peaks. Furthermore, we localize blocks of PMMA at different locations on the A-SRR array to determine the effectiveness of detection of very small amounts of non-uniformly distributed analyte

Observational constraints on thawing quintessence models

We use a dynamical systems approach to study thawing quintessence models, using a multi-parameter extension of the exponential potential which can approximate the form of typical thawing potentials. We impose observational constraints using a compilation of current data, and forecast the tightening of constraints expected from future dark energy surveys, as well as discussing the relation of our results to analytical constraints already in the literature.Comment: 6 pages MNRAS style with 8 figures included. Minor updates to match MNRAS accepted versio

Election turnout statistics in many countries: similarities, differences, and a diffusive field model for decision-making

We study in details the turnout rate statistics for 77 elections in 11 different countries. We show that the empirical results established in a previous paper for French elections appear to hold much more generally. We find in particular that the spatial correlation of turnout rates decay logarithmically with distance in all cases. This result is quantitatively reproduced by a decision model that assumes that each voter makes his mind as a result of three influence terms: one totally idiosyncratic component, one city-specific term with short-ranged fluctuations in space, and one long-ranged correlated field which propagates diffusively in space. A detailed analysis reveals several interesting features: for example, different countries have different degrees of local heterogeneities and seem to be characterized by a different propensity for individuals to conform to the cultural norm. We furthermore find clear signs of herding (i.e. strongly correlated decisions at the individual level) in some countries, but not in others.Comment: 15 pages, 9 figures, 7 table