Finite Temperature Effective Potential for Gauge Models in de Sitter Space

The one-loop effective potential for gauge models in static de Sitter space at finite temperatures is computed by means of the $\zeta$--function method. We found a simple relation which links the effective potentials of gauge and scalar fields at all temperatures. In the de Sitter invariant and zero-temperature states the potential for the scalar electrodynamics is explicitly obtained, and its properties in these two vacua are compared. In this theory the two states are shown to behave similarly in the regimes of very large and very small radii a of the background space. For the gauge symmetry broken in the flat limit ($a \to \infty$) there is a critical value of a for which the symmetry is restored in both quantum states. Moreover, the phase transitions which occur at large or at small a are of the first or of the second order, respectively, regardless the vacuum considered. The analytical and numerical analysis of the critical parameters of the above theory is performed. We also established a class of models for which the kind of phase transition occurring depends on the choice of the vacuum.Comment: 23 pages, LaTeX, 5 figure.ep

Social signals and sustainability: ambiguity about motivations can affect status perceptions of efficiency and curtailment behaviors

Perceived status can affect the diffusion of pro-environmental behaviors and sustainable consumption. However, the status of different forms of sustainable consumption has not been adequately explored. Previous studies suggest that curtailment behaviors are associated with low or neutral status, while efficiency behaviors are associated with high status. However, these studies have generally examined a small number of behaviors. Drawing from costly signaling theory, we developed a mixed methods study to explore whether and why pro-environmental behaviors are perceived to be associated with high or low status, the perceived motivation for those behaviors, and the relationship between motivation and status. We conducted structured, interactive interviews with 71 participants to explore perceptions of 19 behaviors. Using quantitative and qualitative analyses, we find that efficiency is rated higher status than curtailment largely due to monetary considerations. Efficiency is also perceived to be motivated by environmental concern to a greater degree than curtailment. Understanding the motivation for behaviors clarifies the social signal because it provides insights into whether one is incurring personal costs. Importantly, it is often unclear whether low-cost curtailment behaviors are adopted by choice rather than financial need. Ambiguity about the intentionality of behaviors results in such behaviors being perceived as lower status. Those who argue that curtailment will be necessary for long-term sustainability must address status perceptions because social stigmas could hinder their adoption. Overcoming such stigmas may require, indicating that curtailment behaviors are voluntary, but it may be more effective to use social or economic mechanisms to increase efficiency behaviors

Avaliação do efeito do Baculovirus anticarsia sobre Podisus nigrispinus (DALLAS, 1851), predador da lagarta da soja Anticarsia gemmatalis (HUBNER, 1818).

Este trabalho tem como objetivo conhecer os efeitos da ingestão de lagartas da soja infectadas com B. anticarsia pelo predador Podisus nigrispinus, avaliando-se os parâmetros biológicos de cada inseto.bitstream/CNPMA/5854/1/baculovirus_anticarsia.pd

Changes in high-intensity precipitation on the northern Apennines (Italy) as revealed by multidisciplinary data over the last 9000 years

Several record-breaking precipitation events have struck the mountainous area of the Emilia-Romagna region (northern Apennines, Italy) over the last 10 years. As a consequence, severe geomorphological processes such as debris avalanches and debris flows, shallow landslides, and overbank flooding have affected the territory, causing severe damage to human-made structures. The unusual intensity of these phenomena prompted an investigation into their frequency in the past, beyond instrumental time. In the quest for an understanding of whether these phenomena are unprecedented in the region, peat bog and lake deposits were analyzed to infer the frequency of extreme precipitation events that may have occurred in the past. We present the results of a dedicated field campaign performed in summer 2017 at Lake Moo in the northern Apennines, a 0.15 km2peat bog located at an altitude of 1130ma.s.l. During the extreme precipitation event of 13-14 September 2015, several debris flows generated by small streams affected the Lake Moo plain. In such a small drainage basin (<2 km2), high-density floods can be triggered only by high-intensity precipitation events. The sedimentary succession (ca. 13m thick) was studied through the drilling of two cores and one trench. The sequence, characterized by clusters of coarse-grained alluvial deposits interbedded with organic-rich silty clays and peat layers, was analyzed by combining sedimentological, pollen, microanthracological and pedological data with radiocarbon dating (AMS 14C) in an innovative multidisciplinary approach for this area. Original data acquired during the field campaign were also correlated with other specific paleoclimatic proxies available in the literature for the northern Apennines area. We discover that the increase in extreme paleoflooding, associated with coarse-grained deposits similar to the ones observed recently, correlates well with the warm phases of the Holocene Thermal Maximum and with the ongoing warming trend observed that started at the beginning of the last century

Thermal Fields, Entropy, and Black Holes

In this review we describe statistical mechanics of quantum systems in the presence of a Killing horizon and compare statistical-mechanical and one-loop contributions to black hole entropy. Studying these questions was motivated by attempts to explain the entropy of black holes as a statistical-mechanical entropy of quantum fields propagating near the black hole horizon. We provide an introduction to this field of research and review its results. In particular, we discuss the relation between the statistical-mechanical entropy of quantum fields and the Bekenstein-Hawking entropy in the standard scheme with renormalization of gravitational coupling constants and in the theories of induced gravity.Comment: 44 pages, LaTeX fil

Avaliação da espectroscopia de infravermelho próximo (NIR) para determinação da concentração de nitrogênio total em amostras de grãos de soja.

A determinação da concentração de nitrogênio (N) pelo método Kjeldhal é considerada padrão para determinação de N total. Entretanto, este método gera alta quantidade de resíduos, é moroso e passível de erros durante a destilação e a titulação. Por outro lado, a determinação indireta do teor de proteína nos grãos de soja, por meio da espectroscopia no infravermelho próximo (NIR) de vem sendo realizada com sucesso na Embrapa Soja. Por se tratar de um método que não gera resíduos, rápido e que pode ser realizado em amostras de grãos “in natura” e estar bem calibrado para a determinação do teor de proteínas em grãos de soja, o objetivo do presente trabalho foi avaliar a viabilidade de utilização do NIR em substituição ao método Kjeldahl para determinação da concentração de N total em grãos de soja. Para isso, foram selecionadas 96 amostras nas quais foram determinadas as concentrações de N pelo método Kjeldahl (padrão de comparação) e os teores de proteína com o NIR, que foram convertidos em N, por meio do fator 6,25. As concentrações foram comparadas seguindo o teste proposto por Leite & Oliveira (2002). Originalmente não houve identidade entre os métodos, porém, ao se estimar o teor de N em função da leitura pelo NIR, verificou-se a existência de tendência linear entre os resíduos da regressão e os teores de N pelo método padrão. Assim, ao se corrigir esse desvio sistemático, a estimativa dos teores de N em função da leitura do NIR resultou em teores estatisticamente idênticos aos do método padrão. Portanto, muito embora estudos adicionais sejam necessários, a determinação indireta do teor de N pelo NIR aparenta ser uma metodologia viável

Heat-kernel Coefficients and Spectra of the Vector Laplacians on Spherical Domains with Conical Singularities

The spherical domains $S^d_\beta$ with conical singularities are a convenient arena for studying the properties of tensor Laplacians on arbitrary manifolds with such a kind of singular points. In this paper the vector Laplacian on $S^d_\beta$ is considered and its spectrum is calculated exactly for any dimension $d$. This enables one to find the Schwinger-DeWitt coefficients of this operator by using the residues of the $\zeta$-function. In particular, the second coefficient, defining the conformal anomaly, is explicitly calculated on $S^d_\beta$ and its generalization to arbitrary manifolds is found. As an application of this result, the standard renormalization of the one-loop effective action of gauge fields is demonstrated to be sufficient to remove the ultraviolet divergences up to the first order in the conical deficit angle.Comment: plain LaTeX, 23 pp., revised version, a misprint in expressions (1.8) and (4.38) of the second heat coefficient for the vector Laplacian is corrected. No other change