Evolutionary and Pulsational Properties of Ultra-massive White Dwarfs. The Role of Oxygen-Neon Phase Separation.

The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018Ultra-massive hydrogen-rich white dwarf stars are expected to harbour oxygen/neon cores resulting from semidegenerate carbon burning when the progenitor star evolves through the super asymptotic giant branch (S-AGB) phase. These stars are expected to be crystallized by the time they reach the ZZ Ceti domain. We show that crystallization leads to a phase separation of oxygen and neon in the core of ultra-massive white dwarfs, which impacts markedly the pulsational properties, thus offering a unique opportunity to infer and test the process of crystallization and phase separation in white dwarf stars.Astronom

Um sistema de recomendação de conteúdo suportado pela computação distribuída

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Araranguá. Curso de Tecnologias da Informação e Comunicação.Desde a sua criação, a Internet e mais especificamente a Web, vem passando por grandes modificações. Atualmente, usuários possuem um papel fundamental, não somente consumindo informações, mas também provendo novos conteúdos. Este cenário e os avanços da Tecnologia da Informação tem promovido um aumento vertiginoso no volume de informações disponíveis. A partir disto surgem desafios, entre eles, como permitir que o usuário realize escolhas mais adequadas. Neste contexto, encontram-se os Sistemas de Recomendação com o intuito de auxiliar usuários na tomada de decisão, bem como, a Computação Distribuída como infraestrutura de base para lidar com grandes volumes de informação. A partir disto, o presente trabalho propõe um sistema voltado à recomendação de conteúdo textual através das abordagens de filtragem colaborativa e baseada em conteúdo. Visando permitir a avaliação da proposição deste trabalho foi elaborado um modelo de dados e desenvolvido um protótipo. O protótipo possibilita a geração de informações nas duas principais abordagens de recomendação. Possui ainda a capacidade de realizar o processamento de maneira distribuída. As informações processadas e geradas através da aplicação do protótipo permitem a sugestão de itens, em que no presente trabalho se referem a documentos. Pode-se afirmar que os resultados no que tange a sugestão de conteúdo são consistentes e compatíveis com a literatura da área de Sistemas de Recomendação. Ressalta-se ainda que o desenvolvimento de sistemas distribuídos contribui para área em questão visto que o desempenho frente a grande volumes de informação é fundamental para que se possa produzir insumos que auxiliem usuários em suas escolhas.Since its creation the Internet and more specifically the Web has changed dramatically. Nowadays, users have a key role not only consuming information but also providing new content. This scenario and the advances in Information Technology have fostered the increase in the volume of information available. From this challenges arise, among them, how to allow users to perform more appropriate choices. In this context, there are the Recommender Systems in order to aid users in decision making and Distributed Computing as the base infrastructure to handle large volumes of information. From this, the present work proposes a system towards recommendation of textual content through collaborative filtering and content-based approaches. To allow the evaluation of the proposition a data model has been designed as well as has been developed a prototype. The prototype enables the generation of information on the two major recommendation approaches. It also has the ability to carry out the processing in a distributed manner. The information generated and processed by the prototype allows the suggestion of items which in the present study refers to documents. It can be stated that the results regarding the suggested content are consistent and compatible with the literature in the area of Recommender Systems. It is noteworthy that the development of distributed systems contributes to the area in question since performance against large volumes of information is crucial in order to produce products that can assist users in their choice

For post-statist geographies

This article critically investigates past and contemporary treatments of the state within geographical scholarship. We propose that there is a silent statism within geography that has shaped it in ways that limit geographical imaginations. Statism, herein, refers to a pervasive, historically contingent organisational logic that valourises and naturalises sovereign, coercive, and hierarchical relationships, within and beyond state spaces. We argue that although the explicit, colonial statism that characterised early geography is past, traces of statism nonetheless underpin much of the discipline. While political geography has increasingly critiqued ‘state-centrism’, we argue that it is essential to move beyond critique alone. Using anarchist state theory to critically build upon perspectives in geography, we argue that statism is intellectually and politically problematic and should be recast as an active constituent of unequal social relations. In turn, we outline five core myths that form its logical foundations. In concluding, three initial areas in which post-statist geographies can make inroads are identified: interrogating intersections between statism and other power relations; constructing post-statist epistemologies and methodologies; and addressing how the state is represented in geographical work

Computational investigations of polymerase enzymes: Structure, function, inhibition, and biotechnology

AbstractDNA and RNA polymerases (Pols) are central to life, health, and biotechnology because they allow the flow of genetic information in biological systems. Importantly, Pol function and (de)regulation are linked to human diseases, notably cancer (DNA Pols) and viral infections (RNA Pols) such as COVID‐19. In addition, Pols are used in various applications such as synthesis of artificial genetic polymers and DNA amplification in molecular biology, medicine, and forensic analysis. Because of all of this, the field of Pols is an intense research area, in which computational studies contribute to elucidating experimentally inaccessible atomistic details of Pol function. In detail, Pols catalyze the replication, transcription, and repair of nucleic acids through the addition, via a nucleotidyl transfer reaction, of a nucleotide to the 3′‐end of the growing nucleic acid strand. Here, we analyze how computational methods, including force‐field‐based molecular dynamics, quantum mechanics/molecular mechanics, and free energy simulations, have advanced our understanding of Pols. We examine the complex interaction of chemical and physical events during Pol catalysis, like metal‐aided enzymatic reactions for nucleotide addition and large conformational rearrangements for substrate selection and binding. We also discuss the role of computational approaches in understanding the origin of Pol fidelity—the ability of Pols to incorporate the correct nucleotide that forms a Watson–Crick base pair with the base of the template nucleic acid strand. Finally, we explore how computations can accelerate the discovery of Pol‐targeting drugs and engineering of artificial Pols for synthetic and biotechnological applications.This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Structure and Mechanism > Computational Biochemistry and Biophysics Software > Molecular Modelin

A reconstrução habermasiana do materialismo histórico: a teoria comunicativa enquanto crítica da economia política

Since its initiative to reconstitute the praxis at the core of social and critical theories, Jürgen Habermas presents in his writings a reconstructive approach of historical materialism. Outlining his intent firstly in Theory and practice, the author draws basilar points of his intellectual project in central works as Knowledge and human interests, from 1968, Technology and science as ?ideology?, also from the same year, Legitimation crisis, from 1973, until reaching the reconstructivism properly named in Towards a reconstruction of historical materialism, from 1976, where take places a systematization of the premises that supports his communicative theory towards the conjectural challenges posed by the changes in historical and social reality to marxist thought. Enquiring the persistence of the dialectic between productive forces and production relations, Habermas theorizes that class struggle no longer express the glaring contradictions in economic and political relations and that, for the continuity of social development, new evolutionary elements would have been systematized in the institutionalization of conflicts of interests. Such elements would be subjectively linked to processes of social learning, performing the constitution of individual and organizational identities that, beyond the classist arrangements, would allow the formation of emancipatory behaviours oriented by the mutual understanding and by the search for consensus through the discursivity. In this context, we propose to analyse the path covered by the author in grounding language and interaction as new dimensions capable of grasping these symbolic and subjective mediations in the reconstruction of what, despite the materialist comprehension of history, would be the core elements of the human gender socialization by the communicative reason and action.Desde sua iniciativa em reconstituir a práxis no cerne das teorias sociais e críticas, Jürgen Habermas situa em seus escritos uma disposição de reconstrução do materialismo histórico. Esboçando seu intento já em Teoria e práxis, o autor traça pontos basilares de seu projeto intelectual em obras centrais como Conhecimento e interesse, de 1968, Técnica e ciência como ?ideologia?, também do mesmo ano, e A crise de legitimação do capitalismo tardio, de 1973, até chegar ao reconstrutivismo propriamente dito em A reconstrução do materialismo histórico, de 1976, onde sistematiza de modo mais detido os pressupostos de sustentação de sua teoria comunicativa frente aos desafios colocados pelas transformações da realidade histórica e social da conjuntura ao pensamento marxista. Questionando a persistência da dialética entre forças produtivas e relações de produção, Habermas teoriza que a luta de classes já não mais expressaria as contradições manifestas nas relações econômicas e políticas e que, para a continuidade do desenvolvimento social, teriam se sistematizado novos elementos evolutivos frente à institucionalização dos conflitos de interesses. Tais elementos estariam subjetivamente ligados a processos de aprendizagem social, desempenhando a constituição de identidades individuais e organizacionais que, para além das disposições classistas, permitiriam a formação de comportamentos emancipatoriamente orientados pelo entendimento mútuo e pela busca de consensos pela discursividade. Neste contexto, nos propomos a analisar o percurso do autor na fundamentação da linguagem e da interação como novas dimensões capazes de apreender estas mediações simbólicas e subjetivas na reconstrução do que, em detrimento da compreensão materialista da história, seriam os elementos nucleares de socialização do gênero humano pela razão e pela ação comunicativaDados abertos - Sucupira - Teses e dissertações (2013 a 2016

Diario de los literatos de España : en que se reducen a compendio los escritos de los autores españoles, y se hace juicio de sus obras desde el año MDCCXXXVIII : tomo III : contiene las que se han publicado en los meses de julio, agosto, y septiembre

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Autores tomados de prelim.Sign.: [asterisco]8, A-Z8, 2A-2C8AntepPort. con esc. xil. rea

Study of Thick CZT Detectors for X-ray and Gamma-Ray Astronomy

CdZnTe (CZT) is a wide bandgap II-VI semiconductor developed for the spectroscopic detection of X-rays and {\gamma}-rays at room temperature. The Swift Burst Alert Telescope is using an 5240 cm2 array of 2 mm thick CZT detectors for the detection of 15-150 keV X-rays from Gamma-Ray Bursts. We report on the systematic tests of thicker (\geq 0.5 cm) CZT detectors with volumes between 2 cm3 and 4 cm3 which are potential detector choices for a number of future X-ray telescopes that operate in the 10 keV to a few MeV energy range. The detectors contacted in our laboratory achieve Full Width Half Maximum energy resolutions of 2.7 keV (4.5%) at 59 keV, 3 keV (2.5%) at 122 keV and 4 keV (0.6%) at 662 keV. The 59 keV and 122 keV energy resolutions are among the world-best results for \geq 0.5 cm thick CZT detectors. We use the data set to study trends of how the energy resolution depends on the detector thickness and on the pixel pitch. Unfortunately, we do not find clear trends, indicating that even for the extremely good energy resolutions reported here, the achievable energy resolutions are largely determined by the properties of individual crystals. Somewhat surprisingly, we achieve the reported results without applying a correction of the anode signals for the depth of the interaction. Measuring the interaction depths thus does not seem to be a pre-requisite for achieving sub-1% energy resolutions at 662 keV.Comment: 15 pages, 11 figure