On the available energy of an axisymmetric vortex

A theory of available energy for axisymmetric circulations is presented. The theory is a generalization of the classical theory of available potential energy, in that it accounts for both thermal and angular momentum constraints on the circulation. The generalization relies on the Hamiltonian structure of the (conservative) dynamics, is exact at finite amplitude, and has a local form. Application of the theory is presented for the case of an axisymmetric vortex on an f -plane in the context of the Boussinesq equations.

Energetics of a symmetric circulation including momentum constraints

A theory of available potential energy (APE) for symmetric circulations, which includes momentum constraints, is presented. The theory is a generalization of the classical theory of APE, which includes only thermal constraints on the circulation. Physically, centrifugal potential energy is included along with gravitational potential energy. The generalization relies on the Hamiltonian structure of the conservative dynamics, although (as with classical APE) it still defines the energetics in a nonconservative framework. It follows that the theory is exact at finite amplitude, has a local form, and can be applied to a variety of fluid models. It is applied here to the f -plane Boussinesq equations. It is shown that, by including momentum constraints, the APE of a symmetrically stable flow is zero, while the energetics of a mechanically driven symmetric circulation properly reflect its causality.

Spatial housing economics: a survey

This introduction to the Virtual Special Issue surveys the development of spatial housing economics from its roots in neo-classical theory, through more recent developments in social interactions modelling, and touching on the role of institutions, path dependence and economic history. The survey also points to some of the more promising future directions for the subject that are beginning to appear in the literature. The survey covers elements hedonic models, spatial econometrics, neighbourhood models, housing market areas, housing supply, models of segregation, migration, housing tenure, sub-national house price modelling including the so-called ripple effect, and agent-based models. Possible future directions are set in the context of a selection of recent papers that have appeared in Urban Studies. Nevertheless, there are still important gaps in the literature that merit further attention, arising at least partly from emerging policy problems. These include more research on housing and biodiversity, the relationship between housing and civil unrest, the effects of changing age distributions - notably housing for the elderly - and the impact of different international institutional structures. Methodologically, developments in Big Data provide an exciting framework for future work.

Barnfri : en stigmatiserad position

Childfree: a stigmatized position International research has addressed the subject but in Sweden voluntary childlessness has until now been overlooked. This article draws on qualitative, semi-structured interviews with 21 Swedish childfree women. The interviews focused their decision not to have children and attitudes they faced due to their rejection of motherhood. They all had encountered pressure to conform to a pronatalistic norm, proclaiming parenthood to be self-evident in an adult normal life. The results highlight different strategies used by the women to avoid instigating the dislike of those around them. The article argues that understanding childfree as a stigmatized position helps providing new insights to what conditions the social relations between the childfree and ‘the normals’, i.e. persons who advocate having children. Further, viewing the childfree as a stigmatized group has theoretical implications that contribute to developing Goffman’s classical theory of social stigma.

Responsabilidade social das empresas e valores humanos: um estudo sobre a atitude dos gestores brasileiros

In the last decades of the 21st century, Corporate Social Responsibility (CSR) has become one of the most widely debated issues in business management, concerning researchers, politicians, managers and society at large. With multilateral implications in economic and social life, CSR refers, essentially, to the discussion about the boundaries of business intervention in society and the ethical limits that should regulate that intervention. It questions the impact of business practices in social well-being, the role left for corporations and for the State in attending to community needs, and which are, at last, the responsibilities that tie enterprises to society. In this research, CSR is approached from the perspective of its ethical foundations, based on the moral reasoning of the business manager, as a key organizational leader with relevant decision power. Specifically, the research aims to understand how the personal human value system and the ethical orientation of managers influence their attitude towards CSR, considering this attitude as an indicator of managerial behavior that translates into corporate performance. Theoretically, CSR concept is discussed and presented as a set of social commitments, based on a strict interpretation of its meaning. As to human values, its philosophical roots are briefly analyzed and Schwartz modern motivational theory is addressed as main reference for studying the personal value system of managers in this research. Concerning ethics, based on classical theory from moral philosophy, references are seek in John Stuart Mill¿s utilitarianism, Immanuel Kant¿s deontological absolutism, John Rawls¿s theory of justice and the ethics of virtue inspired by Aristotle¿s moral thoughts. Based on an extended literature review, research hypothesis are proposed as part of a theoretical model of analysis named Individual Attitude Towards Social Responsibility Model. In order to test the theory¿s empirical validity, it was conducted a field study with 252 Brazilian managers, mainly from the metropolitan areas of São Paulo and Rio de Janeiro. Results show that managerial attitude aligned with CSR principles is favored by conservative personal values, protectors of stability and centered on collective will, and by an ethical orientation based on egalitarianism as postulated by distributive justice principles. However, results also show that the influence of values and personal ethics on managerial attitude towards CSR only occur in managers younger than 30 years old. Findings and their meanings are discussed, as well as summarized in the Axiological and Ethical Determinants of Managers¿ Social Commitment Model. Finally, methodological limitations are evaluated and clues for further research are suggested.

Contratos de performance sob risco e na ausência de incentivo

Este trabalho mostra que a solução ótima do contrato de remuneração do empregado não é de salário fixo quando sua utilidade reserva é uma função de um fator que pode variar. A remuneração ótima do empregado incluirá um bônus que será também uma função do mesmo fator que modifica sua utilidade reserva, mesmo que tal fator não dependa do seu esforço e que o agente seja avesso ao risco. Esse resultado contrasta com a teoria clássica segundo a qual só se deveria alocar risco ao funcionário quando tal contrato fosse necessário para prover os incentivos para um esforço maior do agente. Outra conclusão desse trabalho é que existe um limite para o tamanho do risco que o funcionário assume no contrato ótimo, ou seja, o valor do bônus é uma função crescente da diferença dos valores da utilidade reserva nos diferentes cenários possíveis até certo ponto apenas e a partir de determinado valor para essa diferença, a magnitude do bônus se mantém estável.

Estimação do desconto de reequilíbrio ótimo em concessões rodoviárias através da metodologia das opções reais

Este trabalho propõe um novo modelo para avaliação, em tempo discreto, do desconto de reequilíbrio em contratos de concessão rodoviária, a partir de conceitos da Teoria Clássica de Finanças e da Teoria de Opções Reais. O modelo desenvolvido permitiu incorporar flexibilidades decorrentes de incertezas nas situações reais, como decisões gerenciais, vieses de comportamento e componentes políticos, comumente presentes em contratos de concessões rodoviária. Os resultados obtidos, utilizando-se como estudo de caso a BR-262, sinalizaram que há espaço para uma melhor intervenção regulatória com relação ao mecanismo do desconto de reequilíbrio, no sentido de prover melhores incentivos aos concessionários.

Filtros acústicos em cristais fonônicos

In this work, we have studied the acoustic phonon wave propagation within the periodic and quasiperiodic superlattices of Fibonacci type. These structures are formed by phononic crystals, whose periodicity allows the raise of regions known as stop bands, which prevent the phonon propagation throughout the structure for specific frequency values. This phenomenon allows the construction of acoustic filters with great technological potential. Our theoretical model were based on the method of the transfer matrix, thery acoustics phonons which describes the propagation of the transverse and longitudinal modes within a unit cell, linking them with the precedent cell in the multilayer structure. The transfer matrix is built taking into account the elastic and electromagnetic boundary conditions in the superllatice interfaces, and it is related to the coupled differential equation solutions (elastic and electromagnetic) that describe each model under consideration. We investigated the piezoelectric properties of GaN and AlN the nitride semiconductors, whose properties are important to applications in the semiconductor device industry. The calculations that characterize the piezoelectric system, depend strongly on the cubic (zinc-bend) and hexagonal (wurtzite) crystal symmetries, that are described the elastic and piezoelectric tensors. The investigation of the liquid Hg (mercury), Ga (gallium) and Ar (argon) systems in static conditions also using the classical theory of elasticity. Together with the Euler s equation of fluid mechanics they one solved to the solid/liquid and the liquid/liquid interfaces to obtain and discuss several interesting physical results. In particular, the acoustical filters obtained from these structures are again presented and their features discussed

On fuzzy ideals and fuzzy filters of fuzzy lattices

In the literature there are several proposals of fuzzi cation of lattices and ideals concepts. Chon in (Korean J. Math 17 (2009), No. 4, 361-374), using the notion of fuzzy order relation de ned by Zadeh, introduced a new notion of fuzzy lattice and studied the level sets of fuzzy lattices, but did not de ne a notion of fuzzy ideals for this type of fuzzy lattice. In this thesis, using the fuzzy lattices de ned by Chon, we de ne fuzzy homomorphism between fuzzy lattices, the operations of product, collapsed sum, lifting, opposite, interval and intuitionistic on bounded fuzzy lattices. They are conceived as extensions of their analogous operations on the classical theory by using this de nition of fuzzy lattices and introduce new results from these operators. In addition, we de ne ideals and lters of fuzzy lattices and concepts in the same way as in their characterization in terms of level and support sets. One of the results found here is the connection among ideals, supports and level sets. The reader will also nd the de nition of some kinds of ideals and lters as well as some results with respect to the intersection among their families. Moreover, we introduce a new notion of fuzzy ideals and fuzzy lters for fuzzy lattices de ned by Chon. We de ne types of fuzzy ideals and fuzzy lters that generalize usual types of ideals and lters of lattices, such as principal ideals, proper ideals, prime ideals and maximal ideals. The main idea is verifying that analogous properties in the classical theory on lattices are maintained in this new theory of fuzzy ideals. We also de ne, a fuzzy homomorphism h from fuzzy lattices L and M and prove some results involving fuzzy homomorphism and fuzzy ideals as if h is a fuzzy monomorphism and the fuzzy image of a fuzzy set ~h(I) is a fuzzy ideal, then I is a fuzzy ideal. Similarly, we prove for proper, prime and maximal fuzzy ideals. Finally, we prove that h is a fuzzy homomorphism from fuzzy lattices L into M if the inverse image of all principal fuzzy ideals of M is a fuzzy ideal of L. Lastly, we introduce the notion of -ideals and - lters of fuzzy lattices and characterize it by using its support and its level set. Moreover, we prove some similar properties in the classical theory of - ideals and - lters, such as, the class of -ideals and - lters are closed under intersection. We also de ne fuzzy -ideals of fuzzy lattices, some properties analogous to the classical theory are also proved and characterize a fuzzy -ideal on operation of product between bounded fuzzy lattices L and M and prove some results.

EXPANSION OF THE DISTURBING FUNCTION FOR HIGH ECCENTRICITY AND LARGE-AMPLITUDE OF LIBRATION

Following some ideas, developed by Woltjer (1928), Message (1989), Yokoyama (1988, 1989) and Duriez (1990) an expansion of the disturbing function is given for high values of the eccentricity and large amplitude of libration. The classical expansion can be obtained as a particular case of the present model. Several asteroids with high eccentricity and large amplitude of libration are tested and the results are much better than those obtained from the classical theory.

Cinética de cristalização em vidros teluritos do sistema TLWN

Pós-graduação em Ciência dos Materiais - FEIS

Análise de estabilidade de sistemas dinâmicos híbridos e descontínuos modelados por semigrupos:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O regime de metas de inflação no Brasil: um exame teórico e empírico de seu funcionamento

The Inflation targeting regime is a concept of monetary policy which was adopted by several countries in the 90’s; Brazil being among these countries, having adopted it in 1999 after a currency crisis. With it theoretical structure regulated by the New – Classical theory and having as its main characteristic the prior announcement of a numerical target for the inflation, this regime was adopted by countries attempting to achieve a prices stability. The present project is going to explain the theoretical basis of the regime, as well as its implementation process in Brazil and the criticism it received. However, the main focus will be on the discussion of the employment of the IPCA (Consumer Price Index) as a measuring index for Brazil’s inflation

Uma análise da ascensão chinesa a partir da Teoria do Imperialismo

Pós-graduação em Ciências Sociais - FFC

O regime de metas de inflação: fundamentação teórica e abordagem empírica para o Brasil

Pós-graduação em Economia - FCLAR