Probing the Effects of Lorentz-Symmetry Violating Chern-Simons and Ricci-Cotton Terms in Higher Derivative Gravity

The combined effects of the Lorentz-symmetry violating Chern-Simons and Ricci-Cotton actions are investigated for the Einstein-Hilbert gravity in the second order formalism modified by higher derivative terms, and their consequences on the spectrum of excitations are analyzed. We follow the lines of previous works and build up an orthonormal basis of operators that splits the fundamental fields according to their individual degrees of freedom. With this new basis, the attainment of the propagators is remarkably simplified and the identification of the physical and unphysical modes gets a new insight. Our conclusion is that the only tachyon- and ghost-free model is the Einstein-Hilbert action added up by the Chern-Simons term with a time-like vector of the type $v^{\mu} = (\mu,\vec{0})$. Spectral consistency imposes taht the Ricci-Cotton term must be switched off. We then infer that gravity with Lorentz-symmetry violation imposes a drastically different constraint on the background if compared to usual gauge theories whenever conditions for suppression of tachyons and ghosts are required.Comment: 15 pages. It coincides with the version published in Phys. Rev.

Consequences of investment contract duration on the valuation of firms in maturity stage

Investment contract duration is a key parameter for Venture Capital funds operation. Variables influencing the decision around this parameter are usually treated in general principles in the classical financial literature leaving plenty of room for context sensitive research. As such, we studied variables influencing investment contract duration by investigating the performance of mature Portuguese firms that have been (partially) held by Venture Capital funds. Using a sample of 38 firms, sold out by Venture Capital funds between 1995 and 2004, we evaluated the performance of these firms using performance and sustainability indicators. We found evidence that Sales Growth, Exports, Book Value, Headcount and a good Coverage of ISO Standards Implementation influenced the investment contract duration.info:eu-repo/semantics/acceptedVersio

Международный культурно-академический обмен: опыт личного и научного роста

В этой статье описывается опыт трех студентов, участвовавших в программе международной академической мобильности в рамках специальности Металлургическое машиностроение. Это отчет о пребывании студентов в России в Уральском федеральном университете, который стал возможным благодаря Федеральному университету Оуро Прето (UFOP) и Совету по международным делам (CAINT). Обмен, который проходил с начала февраля до конца июля, стал возможностью для приобретения новых научных, культурных и социальных знаний, в том числе знаний в области бизнеса, экономики и менеджмента. Надеемся на стимулирование специальности «Международная мобильность» на высшем уровне, в виду ее важности для улучшения академического образования и повышения уровня подготовки выпускников из Бразилии путем научного и культурного обмена.This article has objective describe an experience of three students to integrate a program of International Mobility Academic, during the graduate in Metallurgical Engineering. It is an account of students experience at Russia, at Ural Federal University, made possible by Federal University of Ouro Preto – (UFOP) and Coordinating international affairs – (CAINT). The exchange experience, that is preview to have started on February and end on July, had possibility the acquisition of new scientific knowledge, cultural and social, including learning Business, Economic and Management. As a contribution, hope to stimulate and intensify the International Mobility specialty in the ambit of graduate, considering the it important to improvement of academic education and the excellence on superior graduate Brazilian by scientific exchange and culture on exterior

On the distribution of an effective channel estimator for multi-cell massive MIMO

Accurate channel estimation is of utmost importance for massive MIMO systems to provide significant improvements in spectral and energy efficiency. In this work, we present a study on the distribution of a simple but yet effective and practical channel estimator for multi-cell massive MIMO systems suffering from pilot-contamination. The proposed channel estimator performs well under moderate to aggressive pilot contamination scenarios without previous knowledge of the inter-cell large-scale channel coefficients and noise power, asymptotically approximating the performance of the linear MMSE estimator as the number of antennas increases. We prove that the distribution of the proposed channel estimator can be accurately approximated by the circularly-symmetric complex normal distribution, when the number of antennas, M, deployed at the base station is greater than 10

Gastronomic experience and consumer behavior: Analyzing the influence on destination image

Gastronomy experiences are becoming a fundamental factor that influences the making of a decision regarding choosing a travel destination, as well as being a crucial factor in shaping tourists’ satisfaction regarding their overall travel experience. The aim of the study is to identify and explain the simultaneous impact of the key factors that influence a gastronomic experience and their impact on tourists’ satisfaction with a trip and the destination’s brand. These issues were addressed within the context of Ukraine, as this is an overlooked area of academic research, and an online survey was conducted, targeting domestic and international tourists. Structural equation modeling was used to assess and reveal the proposed hypotheses in the model. The study contributed to the theoretical understanding of the key factors that increases the occurrence of a memorable gastronomic experience and the relationship between the experience of food and its role in the satisfaction of and the perceived brand of a destination. Moreover, the finding showed that past experience and prior knowledge have a positive influence on the gastronomy experience, while tourists’ prior knowledge effects the perceived quality of a destination’s cuisine, as well as the food activities in the destination. Linkages in the model were empirically supported by statistical analyses. Nonetheless, the various level of the tourists’ involvement with gastronomy might be used as an input to examine and improve the memorable gastronomic experience on-site. The research simultaneously highlighted the importance of gastronomy to tourist destinations for positioning on international and domestic markets. The paper not only provides theoretical but also practical implications. The hospitality and tourism businesses benefit from acknowledging the importance of local food and the local food market. The findings of this study are also deemed to assist destination marketers who observe that tourists have become more demanding in search of unique experiences offered by destinations.info:eu-repo/semantics/publishedVersio

Recycling of porous bituminous mixtures

Once flexible pavements reach minimal bearing capacity, their structural rehabilitation is normally undertaken us ing bituminous mixture overlay. The number of layers and the thickness depend of the existing quality of the pavement and of the required quality determined by the rehabilitation program for a next life period. The rehabilitation of a pavement with a porous bituminous mixture wearing course is usually undertaken without any treatment to increase its bearing capacity. The bearing capacity of this type of mixture can be increased by the use of a grout to fill its voids, increasing its resistance. The new material is produced by spreading a grout over the pavement surface, with the help of rubber scrapers, penetrating the voids of the mixture until it reaches the bottom of the layer. The properties of this material are dependent on void connectivity, in order to allow the grout to flow through them. An adequate viscosity of the grout is essential so as to fill the voids completely. The objective of this paper is to analyse the recycling of porous bituminous mixtures, studying the grout and evaluating new mixture properties in terms of stiffness, fatigue life and permanent deformation

Financial objectives and satisfaction with life: A mixed-method study in surf lifestyle entrepreneurs

Tourism lifestyle entrepreneurs (TLEs) have introduced an innovation in business management based on the region, community, environmental sustainability, and extra financial factors. This type of entrepreneur allows the development of regions by attracting investment and presenting innovative products/services and is an important aid to the local economy. Based on the importance of TLEs, this study aims to explore factors influencing satisfaction with life as a key ingredient to attracting surf TLE. For this purpose, priority was given to obtaining primary data through a sequential approach of mixed methods, first with a quantitative study using survey data of 109 surf TLEs, followed by in-depth interviews. The results show that a good contact network and a strong link to a place influence satisfaction with life in a positive way. As a result, the moderating effect of financial objectives on these relationships alerts destination decision-makers about different entrepreneurial approaches regarding surf businessman attraction. This study makes an important contribution by providing empirical evidence regarding the ongoing discussion about financial vs. non-financial objectives for this type of entrepreneur, showing that both are important for their decision-making process. These results provide valuable insights for several industry stakeholders, namely funders (for grant approval), policymakers (alerting that these entrepreneurs should be addressed considering non-financial objectives), and entrepreneurs (alerting to goal definition patterns).info:eu-repo/semantics/publishedVersio

Traumatismo Crânio-Encefálico em Portugal: Tendências em Doentes Internados de 2000 a 2010

Introduction: Traumatic brain injury has a considerable socio-economic impact, being a major cause of morbi-mortality, often with permanent disability. We sought to characterize health resource utilization of adult traumatic brain injury patients in Portugal between 2000 and 2010. Material and Methods: Retrospective study of medical records of adult patients with ICD9 diagnostic code of traumatic brain injury included in the National Diagnosis Related Groups Database from 2000-2010. Descriptive statistical analysis was performed and trends during the decade were evaluated. Results: We analysed 72 865 admissions to 111 hospitals, 64.1% males, mean age 57.9 ± 21.8 years (18-107). We found a decrease in number of traumatic brain injury in younger patients and an increase in older ones. The number of traffic accidents decreased and the number of falls increased. There was an increase of moderate to severe traumatic brain injury admissions: 47.2% in 2000 / 80% in 2010. Patients admitted in Intensive Care have nearly doubled (15.8% vs 29.5%) as well as the number submitted to neurosurgical procedures (8.2% vs 15.2%). Total mortality increased from 7.1% to 10.6%. Discussion: The decrease of traumatic brain injury may be associated with the trauma prevention campaigns, road network improvement and health politics. The increase in mortality may be related to better pre-hospital care, enabling more severe cases to arrive in hospital alive, and although treated more frequently in Intensive Care and requiring more neurosurgical procedures, they end up having higher mortality. Also this may be due to an increase in patients' age and worse pre-morbid status. Conclusion: Traumatic brain injury in Portugal is changing. Although hospital admissions due to global traumatic brain injury have decreased, mortality rate has increased