Black Rings in (Anti)-deSitter space

We construct solutions for thin black rings in Anti-deSitter and deSitter spacetimes using approximate methods. Black rings in AdS exist with arbitrarily large radius and satisfy a bound |J| \leq LM, which they saturate as their radius becomes infinitely large. For angular momentum near the maximum, they have larger area than rotating AdS black holes. Thin black rings also exist in deSitter space, with rotation velocities varying between zero and a maximum, and with a radius that is always strictly below the Hubble radius. Our general analysis allows us to include black Saturns as well, which we discuss briefly. We present a simple physical argument why supersymmetric AdS black rings must not be expected: they do not possess the necessary pressure to balance the AdS potential. We discuss the possible existence or absence of `large AdS black rings' and their implications for a dual hydrodynamic description. An analysis of the physical properties of rotating AdS black holes is also included.Comment: 38 pages, 6 figures. v2: changes in terminology, refs added. v3: minor improvements, refs added, published versio

Consumers' Perceptions about Food Quality Attributes and Their Incidence in Argentinean Organic Choices

There is an increasing consumers' concern for food safety and quality and, at the same time, there has been a significant market increment in differentiated or high value products consumption, including organic products. The lack of empirical research in Argentina regarding consumers' awareness of food safety brought our attention. Therefore, the objective of this paper is to analyse consumers' perceptions about the risk and quality attributes of food consumption; and to evaluate the incidence of these factors when buying organic products in Argentina. The Lancaster model (1966) provided the theoretical basis for the use of products attributes and characteristics to analyse the incidence of these attributes in consumers' choices. The data used in this study derives from a food consumption survey on organic and non-organic consumers conducted in Buenos Aires City, Argentina, in April 2005. According to consumers' perceptions, 67% were worried about their health, 79% take care in meals, 57% perceived the high risk of hormones and pesticides in food content and 91% of consumers are used to reading labels before or during their purchase. A Logit Binomial Regression Model was applied to explore which factors affected organic food consumption. The results yielded by this model suggest that the consumers with higher educational level, who eat healthy food, and consider food control organisms 'inefficient' are more likely to buy organic products. A high percentage of consumers read and trust label information in Argentina. This has interesting policy implications to promote differentiated and high value products, and to reduce information asymmetries.Food safety, Quality attributes, Consumers, Organics, Food Consumption/Nutrition/Food Safety, Q18, D1,

Contingent Valuation of Consumers’ Willingness-to-Pay for Organic Food in Argentina

Throughout these last years, organic agriculture has undergone a remarkable expansion due, among other things, to the greater interest shown by consumers aware of food safety concerns involving real or perceived quality risks [1]. This paper aims to estimate consumers’ willingness to pay (WTP) for organic food products available in the Argentinean domestic market, with a view to providing some useful insights to gain support and outline strategies for promotion of organic production, marketing, regulation, and labelling programs of organic food products. A Binomial Multiple Logistic Regression model is estimated with data from a food consumption survey conducted in Buenos Aires city, Argentina, in April 2005. The Contingent Valuation Method was chosen in order to calculate their WTP for five organic selected products: Regular Milk, Leafy Vegetables, Whole Wheat Flour, Fresh Chicken and Aromatic Herbs. The empirical results reveal that consumers are willing to pay a premium for these products and that although prices play an important role, lack of store availability and of a reliable regulatory system to mitigate quality risks constraint consumption of organic products in this country.Willingness-to-pay, Food attributes, Organics, Demand and Price Analysis,

Black Hole Monodromy and Conformal Field Theory

The analytic structure of solutions to the Klein-Gordon equation in a black hole background, as represented by monodromy data, is intimately related to black hole thermodynamics. It encodes the "hidden conformal symmetry" of a non-extremal black hole, and it explains why features of the inner event horizon appear in scattering data such as greybody factors. This indicates that hidden conformal symmetry is generic within a universality class of black holes.Comment: 20 pages, v2 minor corrections, updated reference

Willingness to pay for organic food in Argentina: Evidence from a consumer survey

Most food markets do not count on complete information about food quality for consumers. Quality has become a key concept in the new approaches of the Demand Theory (Lancaster, 1966; Antle, 1999), and, therefore, food quality information has turned into a crucial factor when explaining the existing differences between demand profiles. Throughout these last years, organic agriculture has undergone a notorious expansion due, among other things, to the greater interest shown by consumers aware of food safety concerns involving real or potential quality risks perceptions. (Henson, 1996) This paper aims to estimate consumers´ willingness to pay (WTP) for organic food products available in the Argentinean domestic market, with a view to providing useful evidence to the government, and thus gain support in the promotion of organic production, regulation processes and labelling programs. The Contingent Valuation Method (Hanemann, 1984) was selected to estimate WTP. Data derives from a food consumption survey conducted in Buenos Aires city in April 2005. The parameters estimates for the selected products were obtained by applying a Binomial Multiple Logistic Regression. The results indicate that Argentinean consumers are willing to pay a price premium to acquire better quality products. Indeed, this is conditioned by the effective prices in the domestic market, in which price premiums range from 6% to 200%, thereby restricting their acquisition. Besides, the scarce availability of these healthy products has also become another meaningful obstacle for domestic consumption expansion in Argentina.Willingness to pay, Food quality attributes, Organic price premium, Argentina., Food Consumption/Nutrition/Food Safety,

Seasonal dynamic factor analysis and bootstrap inference : application to electricity market forecasting

Year-ahead forecasting of electricity prices is an important issue in the current context of electricity markets. Nevertheless, only one-day-ahead forecasting is commonly tackled up in previous published works. Moreover, methodology developed for the short-term does not work properly for long-term forecasting. In this paper we provide a seasonal extension of the Non-Stationary Dynamic Factor Analysis, to deal with the interesting problem (both from the economic and engineering point of view) of long term forecasting of electricity prices. Seasonal Dynamic Factor Analysis (SeaDFA) allows to deal with dimensionality reduction in vectors of time series, in such a way that extracts common and specific components. Furthermore, common factors are able to capture not only regular dynamics (stationary or not) but also seasonal one, by means of common factors following a multiplicative seasonal VARIMA(p,d,q)×(P,D,Q)s model. Besides, a bootstrap procedure is proposed to be able to make inference on all the parameters involved in the model. A bootstrap scheme developed for forecasting includes uncertainty due to parameter estimation, allowing to enhance the coverage of forecast confidence intervals. Concerning the innovative and challenging application provided, bootstrap procedure developed allows to calculate not only point forecasts but also forecasting intervals for electricity prices.Dynamic factor analysis, Bootstrap, Forecasting, Confidence intervals

Socio-demographic, Clinical, and Genetic Determinants of Quality of Life in Lung Cancer Patients.

Patient reported health-related quality of life (QOL) is a major component of the overall well-being of cancer patients, with links to prognosis. In 6,420 lung cancer patients, we identified patient characteristics and genetic determinants of QOL. Patient responses from the SF-12 questionnaire was used to calculate normalized Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. Further, we analyzed 218 single nucleotide polymorphisms (SNPs) in the p38 MAPK signaling pathway, a key mediator of response to cellular and environmental stress, as genetic determinants of QOL in a subset of the study population (N = 641). Trends among demographic factors for mean PCS and MCS included smoking status (PCS Ptrend < 0.001, MCS Ptrend < 0.001) and education (PCS Ptrend < 0.001, MCS Ptrend < 0.001). Similar relationships were seen for MCS. The homozygous rare genotype of MEF2B: rs2040562 showed an increased risk of a poor MCS (OR: 3.06, 95% CI: 1.05-8.92, P = 0.041). Finally, survival analysis showed that a low PCS or a MCS was associated with increased risks of five-year mortality (HR = 1.63, 95% CI: 1.51-1.77, HR = 1.23, 95% CI: 1.16-1.32, respectively) and there was a significant reduction in median survival time (Plog-rank < 0.001). These findings suggest that multiple factors contribute to QOL in lung cancer patients, and baseline QOL can impact survival

Individual characteristics and career exploration in adolescence

The effects of gender, age and school grade on several career exploration dimensions measured by the Career Exploration Survey were investigated. Subjects were high school students facing an imminent career decision. Regression analyses indicated that sex and grade-level were the most significant and prevailing individual characteristics related to the adolescents’ career exploration behaviours, reactions and beliefs. Implications for career exploration interventions are discussed.JNICT -Junta Nacional de Investigação Científica e Tecnológica(PSU436-92)info:eu-repo/semantics/publishedVersio

Measuring the Terminal Heights of Bolides to Understand the Atmospheric Flight of Large Asteroidal Fragments

The extent of penetration into the Earth's atmosphere of a meteoroid is defined by the point where its kinetic energy is no longer sufficient to produce luminosity. For most of the cases this is the point where the meteoroid disintegrates in the atmosphere due to ablation process and dynamic pressure during flight. However, some of these bodies have particular physical properties (bigger size, higher bulk strength, etc.) or favorable flight conditions (lower entry velocity or/and a convenient trajectory slope, etc.) that allow them to become a meteorite-dropper and reach the ground. In both cases, we define the end of the luminous path of the trajectory as the terminal height or end height. Thus, the end point shows the amount of deceleration till the final braking. We thus assume that the ability of a fireball to produce meteorites is directly related to its terminal height. Previous studies have discussed the likely relationship between fireball atmospheric flight properties and the terminal height. Most of these studies require the knowledge of a set of properties and physical variables which cannot be determined with sufficient accuracy from ground-based observations. The recently validated dimensionless methodology offers a new approach to this problem. All the unknowns can be reduced to only two parameters which are easily derived from observations. Despite the calculation of the analytic solution of the equations of motion is not trivial, some simplifications are admitted. Here, we describe the best performance range and the errors associated with these simplifications. We discuss how terminal heights depend on two or three variables that are easily retrieved from the recordings, provided at least three trajectory (h, v) points. Additionally, we review the importance of terminal heights, and the way they have been estimated in previous studies. Finally we discuss a new approach for calculating terminal heights.Peer reviewe