Lewis A. Coser: a stranger within more than one gate

This article presents a short portrait of Lewis A. Coser (1913–2003), the American sociologist who became renowned as one of the founders of ‘conflict sociology’. Born in Berlin, Coser had to leave his homeland for political reasons and he spent the years before Nazi Germany’s invasion of France in Paris. Coser then fled to the United States and started his academic career there at the College of the University of Chicago. An abridged version of the PhD thesis he wrote at Columbia University was published as The Functions of Social Conflict, which earned him recognition, a promotion, and made him a figure of authority for sociologists in the 1960s. In this article the author draws on archival materials to examine Coser’s life, major publications and achievements. His intellectual trajectory from Marxism to Mertonian Functionalism, his strong commitment to a Weberian view of the separation of politics from scholarship, the breadth of his erudition in literature and classical sociological theory, and his lifelong place in New York intellectual circles and intellectual magazines made him an extraordinary figure even amongst his contemporaries

Aspects of Entanglement Negativity in One Dimensional Critical Systems

In this thesis we study entanglement in one-dimensional critical quantum many-body systems and in particular we will focus on disconnected regions. Given a system in a pure state, to quantify the amount of entanglement between a multicomponent subsystem and the rest of the full system we can use as an entanglement measure the renowned entanglement entropy. However, if we are interested in the entanglement shared among the disconnected regions, the entanglement entropy fails to be a good quantifier. The reason is that the state of the subsystem is in general mixed once the rest is traced out, and the entanglement entropy is a good measure of entanglement only for pure states. A good measure of entanglement in mixed states is the logarithmic negativity, which is the quantitative version of Peres' criterion of separability. The main advantage of the negativity with respect to other entanglement measures is the simplicity of its definition in terms of the density matrix describing the quantum state. Since the definition does not require any variational calculus, it is much more easily computable than any other entanglement measure, and therefore we can obtain some results also in complicated settings such as many-body systems. We will be mostly interested in the configuration where the full system is divided into two parts, A and B. If we do not have access to the degrees of freedom in B, we can describe subsystem A through its reduced density matrix, where the degrees of freedom in B have been traced out. The residual subsystem in A will in general be left in a mixed state. Subsystem A is then divided again into two parts, A_1 and A_2, and we will be interested in the entanglement shared by these two components. Knowing the full density matrix, the logarithmic negativity can be easily computed from the eigenvalues of its partial transpose with respect to the degrees of freedom living in one of the two subsystems A_1 or A_2. However, the full density matrix of a many-body state is in general unaccessible, even numerically, since the size of the matrix grows exponentially with the size of the system. If we concentrate on critical systems whose low-energy physics can be described by a quantum field theory, we can resort to its powerful tools to compute the entanglement properties. In particular the main tool is the replica trick. The entanglement entropy is obtained from the moments of the reduced density matrix, while the negativity can be computed from the moments of the partial transpose. However, even the computation of the integer-order moments is not an easy task, and exact analytical results are known only for the simplest quantum field theories. Hence, throughout the thesis we will usually consider conformal field theories, which have an enhanced set of symmetries and therefore allow for some exact computations. In the Introduction, we will try to frame this work by briefly reviewing some of the main topics in the literature of quantum many-body systems and quantum field theories where entanglement plays a crucial role. We will also describe what are the main features that are requested to a `good' measure of entanglement, and we will review some of the main measures that have been considered so far in the context of quantum information. We will define the entanglement negativity and stress its main advantages, as well as its drawbacks. After reviewing some basic facts of conformal field theories, we will give some technical details on the computation of entanglement entropy and logarithmic negativity in general quantum field theories, which will be needed in the rest of the thesis. In Chap. 2 we will start the study of the entanglement of several disjoint disconnected regions by considering the entanglement that the union of these regions share with the rest of the system. We will compute the integer-order R\ue9nyi entropies of the subsystem from which the entanglement entropy can be obtained through the replica limit. Unfortunately, the exact analytic continuation to real order is still out of reach and therefore the entanglement entropy cannot be computed exactly. However numerical extrapolations allow to obtain some accurate estimates. In the remaining chapters we will focus on the entanglement shared between two non complementary disjoint regions, through the computations of the entanglement negativity in different settings. In Chap. 3, we will consider a global quantum quench starting from a conformal boundary state and evolving through a conformal evolution. A general formula for the mutual information and the logarithmic negativity for two adjacent and disjoint intervals is given in the spacetime limit. In Chap. 4 we focus on the XY chain and we recover a formula for the partial transpose as a sum of four fermionic auxiliary Gaussian density matrices, by generalizing some previous results for the reduced density matrix of spin systems and for the partial transpose of pure fermionc Gaussian states. Even if the computation of the negativity is still out of reach, we can obtain formulas for the integer-order moments of the partial transpose in terms of the correlation matrices relative to the two components and to the region in between them. In Chap. 5 we will study the entanglement negativity for a free Dirac fermion field. Starting from the lattice results, we will obtain a path integral representation of the partial transpose which can be easily generalized to the continuum. With this representation of the partial transpose, we can construct all its integer-order moments and compute them for the simple conformal field theory of the free fermion. Again, the computation of the negativity could not be accomplished due to technical difficulties in the analytic continuation to real order. The same computation has been extended also to the modular invariant Dirac fermion and the Ising model, and the obtained formulas coincide with the ones already present in the literature. This analysis draws an interesting connection between some terms appearing in the formulas for the moments of the partial transpose (as well as of the R\'enyi entropies) found for the lattice models and the ones found for the corresponding theories describing their scaling limit. Whenever possible, all the analytical results will be checked against numerical calculations performed on simple free chain models. In Chaps. 2 and 3 we will consider bosonic Gaussian states, specifically the harmonic chain in its ground state and out of equilibrium, while in Chaps. 4 and 5 we will consider fermionic systems, specifically the XX and Ising spin chains, and the tight-binding model. Finally, we will draw some conclusions and discuss some open problems

Conexiones afrodiaspóricas en las américas: Toni Morrison en Brasil

Admired throughout the world, Toni Morrison’s powerful voice resounds in special ways in Brazil, where she conducted part of her research for Beloved –a novel she considered an interrogation about the legacy of slavery in countries like Brazil and the USA. Initially labeled «politically correct» by Brazilian media, her works have finally achieved great visibility in the twenty-first century thanks to translations, a wide readership and increasing academic attention. In fact, Afro-Brazilian women writers, literary critics, historians, and cultural workers have reached unprecedented recognition in recent decades, along with a belated embrace of Morrison and other Black authors. This essay relies on Black feminist, diasporic and decolonial thinking to investigate how Morrison’s writing connects with the ongoing process of racial awareness and empowerment in Brazil, as well as with the writer Conceição Evaristo.Admirada mundialmente, la poderosa voz de Toni Morrison resuena en Brasil, donde desarrolló parte de su investigación para escribir Beloved, novela que definió como una indagación sobre el legado de la esclavitud en países como Brasil y Estados Unidos. Inicialmente etiquetadas como «políticamente correctas» por la prensa brasileña, sus obras han alcanzado gran visibilidad en el siglo XXI gracias a traducciones, un gran número de lectores y lectoras y una creciente atención académica. De hecho, escritoras, críticas literarias, historiadoras y profesionales culturales afro-brasileñas han logrado notoriedad sin precedentes en las últimas décadas, junto al reconocimiento tardío a Morrison y otros autores y autoras afroamericanas. Este ensayo se basa en el pensamiento feminista negro, diaspórico y decolonial para investigar cómo la escritura de Morrison está vinculada no solo con el proceso hacia la conciencia racial y el empoderamiento en Brasil, sino también con la autora Conceição Evaristo

Beyond the Nuclear Family: A Qualitative Examination of Extended Family Involvement Among American Indian Families

A common practice among American Indian (AI) families, as well as many ethnic minority families, is involving both nuclear and extended family members in raising children. This practice is believed to serve as a protective factor for families against negative outcomes and provide a potential avenue for social support. Several authors have described extended family members being involved in helping to care taking, sharing cultural knowledge and customs, and disciplining youth. As a result, it has been proposed that extended family members help to nurture the parent-child relationship and provide various forms of support to parents. Despite this, the available research with AI families has been limited to specific examinations of their involvement as custodial guardians or in providing kinship care. Given the various roles extended family members play in children’s development, an examination of types of support and impact of support is warranted. The purpose of the current study is to examine how extended family members help support families. Specifically, the study will gain information from the perspectives of caregivers and extended family members on their specific roles in supporting parents and helping to raise children. Qualitative data revealed a broad definition of family which included biological and non-biological family members who help to raise children. Several themes concerning extended family involvement emerged from interviews with caregivers and family members including teaching and reinforcing cultural knowledge and shaping children’s behaviors, for example. Their definitions and perspective are much broader than originally discussed in extant literature. Extended family members described their involvement as providing them a new sense of purpose and helping to keep them active. Findings support and extend previous literature on the involvement of extended family by describing their role in the family and the impact of their involvement. Clinical implications include encouraging clinicians to consider engaging family members actively involved in raising children in helping to deter problematic behavior. Future directions for research are discussed

Forrageiras para corte e pastejo.

A alimentação é um dos itens que mais oneram o custo de produção animal, seja de leite ou de carne. Dessa maneira deve-se ter em mente que os recursos forrageiros disponíveis na fazenda devem permitir a obtenção de elevadas produções de leite e/ou carne por área por um longo período de tempo e de forma econômica, principal meta de quem lida com a atividade agropecuária. Com esse intuito, esta publicação procura englobar informações tecnológicas advindas de resultados de pesquisa, descrevendo características produtivas de diferentes forrageiras tropicais e temperadas e suas diferentes formas de uso, bem como respostas em relação ao manejo, à adubação e à irrigação, apresentando, ainda, resultados quantitativos e qualitativos e recomendações para melhor utilização dessas plantas forrageiras, presentes na maioria dos sistemas de produção animal.bitstream/item/81889/1/Forrageiras-para-corte.pd

Entanglement entropy and negativity of disjoint intervals in CFT: Some numerical extrapolations

The entanglement entropy and the logarithmic negativity can be computed in quantum field theory through a method based on the replica limit. Performing these analytic continuations in some cases is beyond our current knowledge, even for simple models. We employ a numerical method based on rational interpolations to extrapolate the entanglement entropy of two disjoint intervals for the conformal field theories given by the free compact boson and the Ising model. The case of three disjoint intervals is studied for the Ising model and the non compact free massless boson. For the latter model, the logarithmic negativity of two disjoint intervals has been also considered. Some of our findings have been checked against existing numerical results obtained from the corresponding lattice models

A pesquisa em producao de leite a pasto na Embrapa Gado de Leite - 1980 a 1999.

Esta publicação apresenta resultados quantitativos e qualitativos dessas forrageiras, bem como a evolução da pesquisa em produção de leite a pasto na Embrapa Gado de Leite no per(odo compreendido entre 1980 e 1999. Essas forrageiras têm possibilitado, durante a época chuvosa, taxas de lotação de até cinco vacas/ha, além de produções de leite ao redor de 12 kg/vaca/dia, sem o uso de suplementação concentrada. As informações contidas neste documento podem ser úteis para técnicos e produtores que lidam com a atividade leiteira, especialmente aqueles que procuram tecnologias de intensificação da produção de leite à base de pastagens.bitstream/item/81888/1/A-pesquisa-em-producao-de-leite-a-pasto.pd

Viabilidade de implantacao de aveia em pastagens estabelecidas de capim-elefante.

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Sistema monetário brasileiro: a importância para se formar cidadãos críticos

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014Neste artigo apresentamos uma proposta de ensino desenvolvida pelo PIBID da Universidade Federal do Paraná, no projeto Interdisciplinar Pedagogia e Matemática. O projeto aplica-se na Escola Municipal São Luiz com 35 alunos do 5o ano do Ensino Fundamental. A proposta pretende incentivar a pesquisa para aguçar a curiosidade dos alunos. Desenvolve atividades para conhecimento da história do Sistema Monetário Brasileiro e dos conteúdos programáticos à ele pertencentes . Foram utilizados livros, revistas e pesquisas no site oficial do Banco Central do Brasil, além de atividades de resolução de situações-problema utilizando o Real. Foram ressaltadas também questões ligadas à educação financeira e à economia, proporcionando aos alunos reflexões críticas, pró-ativas e autônomas quanto ao uso do dinheir