Cubic interactions and quantum criticality in dimerized antiferromagnets

In certain Mott-insulating dimerized antiferromagnets, triplet excitations of the paramagnetic phase display both three-particle and four-particle interactions. When such a magnet undergoes a quantum phase transition into a magnetically ordered state, the three-particle interaction becomes part of the critical theory provided that the lattice ordering wave vector is zero. One microscopic example is the staggered-dimer antiferromagnet on the square lattice, for which deviations from O(3) universality have been reported in numerical studies. Using both symmetry arguments and microscopic calculations, we show that a nontrivial cubic term arises in the relevant order-parameter quantum field theory, and we assess its consequences using a combination of analytical and numerical methods. We also present finite-temperature quantum Monte Carlo data for the staggered-dimer antiferromagnet which complement recently published results. The data can be consistently interpreted in terms of critical exponents identical to that of the standard O(3) universality class, but with anomalously large corrections to scaling. We argue that the cubic interaction of critical triplons, although irrelevant in two spatial dimensions, is responsible for the leading corrections to scaling due to its small scaling dimension.

Further on the current algebra of WZNW models at and away from criticality

We comment on the off-critical perturbations of WZNW models by a mass term as well as by another descendent operator, when we can compare the results with further algebra obtained from the Dirac quantization of the model, in such a way that a more general class of models be included. We discover, in both cases, hidden Kac-Moody algebras obeyed by some currents in the off-critical case, which in several cases are enough to completely fix the correlation functions.

Amplitude ratios and the approach to bulk criticality in parallel plate geometries

We present analytical and numerical results for the specific heat and susceptibility amplitude ratios in parallel plate geometries. The results are derived using field-theoretic techniques suitable to describe the system in the bulk limit, i.e., (L/ξ±)≫ 1, where L is the distance between the plates and ξ± is the correlation length above (+) and below (-) the bulk critical temperature. Advantages and drawbacks of our method are discussed in the light of other approaches previously reported in the literature.

Factorization and criticality in the anisotropic XY chain via correlations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stretched-exponential behavior and random walks on diluted hypercubic lattices

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Barreiras à gestão ambiental e desempenho operacional de empresas brasileiras: um estudo com modelagem de equações estruturais

Pós-graduação em Engenharia de Produção - FEB

Estudo das propriedades mecânicas de aços microligados produzidos por laminação controlada seguida de resfriamento acelerado para tubos API/DNV usado no projeto pré-sal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fatores para gerenciamento de riscos na cadeia de fornecedores de fabricantes de aeronaves

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rap: o duelo de rimas no cotidiano do jovem

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fatores de risco em cadeia de suprimentos do setor aeroespacial: aspectos qualitativos e quantitativos

The lack of risk management can generate disruption in the supply chain, and there is little literature related to the aerospace industry. This article aims at identifying the risk factors for supply chain of the main Brazilian aircraft manufacturer. Nine risk factors specific to aircraft manufacturers were identified: Environmental, Natural and Political, Supply Chain, Business Strategy, Product Management, Indicators, Organization, Productivity, and Quality and Information System. These factors were quantitatively evaluated with respect to their criticality using the Analytic Hierarchy Process (AHP). The Quality and Productivity factors were considered the most relevant in this study, which can be classified as a single case study. The necessary data were obtained through interviews with professionals from different areas of the studied enterprise.

A Construção do Conhecimento na Atualidade: Um Olhar Sobre o Impacto da Tecnologia

In the paper analyzes the process of knowledge construction in the news regarding the emergence of massive information and communication technologies. In this context, through a qualitative approach, first we examine the potential of production, dissemination, access and use information in a technocratic perspective, and secondly, the negative impacts stemming from the computed mediation, mainly linked to the complexity of policies of democratization of access to information and loss of criticality of science. The focus of this review focuses on the current model of information search and knowledge construction through the Web, outlining aspects inherent to the process in general. Similarly, envision different contributions of information science for the systematization of human knowledge, guided through the social actions of professionals working in various fields, with emphasis on the information representation and retrieval. It is hoped that work can contribute to the current thematic reflection on the production, dissemination and use of information as well as on digital inclusion policies.

A influência da mídia na personalização política dos acadêmicos de jornalismo

This paper aims to present a survey of Journalism students from UNESP (Brazil) and from the University of Seville (Spain) which gathered data to assess the perception of the influence of the media on political decisions in this segment. Through empirical research - qualitative and quantitative – was observed, as a result, that digital media is still gaining ground in political campaigns and the effectiveness of actions organized through on line universe which are beginning to be proven, from the perspective of students. Furthermore, it was possible to realize the criticality that is developed within universities making students able to analyze the context in which they are in

Análise crítica de contratos técnicos como ferramenta para melhoria da gestão da manutenção

Currently, due to the highly competitive search among industries are becoming more tools for managing product that provides higher availability and therefore profitability. Maintenance as a strategic sector and of fundamental importance in business, it seeks to maximize availability and available resources, minimizing costs and waste, which directly impacts the company's results. The present work has as main objective the review of contracts for maintenance services for companies contracted by a chemical company in the Paraíba Valley, since most of its maintenance services are outsourced, and raise these contracts which are more critical and higher risk to the company's success, thus creating a tool for decision-making by maintenance managers in the act of seeking renewals or new contracts to provide services. As a result after drawing up a standard procedure for contracting of services and a better structuring of the same, we developed a method for the calculation of the criticality of the contracts and based on these calculations, charts were prepared which showed that the current scenario of maintenance contracts the company studied. Thus it is possible to evaluate the contracts which are most critical to the success or failure of the company studied, and also pave the way for further studies on how this criticality of a contract can affect the relationship, the contractor x contracted

Aplicação dos conceitos de RCM e a ferramenta FMEA no aumento de confiabilidade em equipamentos de uma indústria química

The growing demand for quality at competitive prices and fast production process put to the test function in the industrial Maintenance. The need for equipment with high availability to fit this fierce competitiveness makes maintenance becomes essentially reliable. Despite this current context, many companies still have an old view of maintenance, focused only on corrective services, and proposals for change are often neglected due to the sense of urgency day to day. Thus, this study aims to demonstrate through theoretical applicability of simple tool, but of great value in increasing reliability within the maintenance sector of an industry, applying the concepts of Reliability Centered Maintenance – RCM and Analysis tool Failure Modes and Effects – FMEA in equipment of a chemical company directly involved in the manufacturing process of the brake fluid, which this product is used in vehicles around the country. That way, you can identify the types, occurrence and criticality of each failure and evaluate assertively decision making for each device, avoiding unnecessary downtime and potential failures of the same

Avaliação ambiental em empresas do distrito industrial Antônio Crepaldi, Presidente Prudente/SP

The sustainable development is the center of many discussions about the environment, economy and society. Environmental issues bring out problems with the fauna and flora, water resources, land use, population growth, residues, basic sanitation, and others. In this sense, the aim of the present work was to develop an environmental diagnostics and propose measures to mitigate the most significant environmental impacts generated by four enterprises in Antonio Crepaldi Industrial District, located at the city of Presidente Prudente/SP. In the study, it was used the methodology proposed by Moreira (2006), and it was done the following activities: monitoring and analyses of the production process, identification of potential environmental aspects and impacts; assessment of the impacts according to its nature, relevance and significance; proposition of measures to mitigate the critical impacts. As a final result, it was obtained an environmental diagnosis about the situation of each of the four companies studied, and it was possible to know the level of criticality of the impacts in each one, and proposing mitigation measures to control or minimizing them, bringing many benefits to the organization