Actin assembly ruptures the nuclear envelope by prying the lamina away from nuclear pores and nuclear membranes in starfish oocytes.

The nucleus of oocytes (germinal vesicle) is unusually large and its nuclear envelope (NE) is densely packed with nuclear pore complexes (NPCs) stockpiled for embryonic development. We showed that breakdown of this specialized NE is mediated by an Arp2/3-nucleated F-actin 'shell' in starfish oocytes, in contrast to microtubule-driven tearing in mammalian fibroblasts. Here, we address the mechanism of F-actin-driven NE rupture by correlated live-cell, super-resolution and electron microscopy. We show that actin is nucleated within the lamina sprouting filopodia-like spikes towards the nuclear membranes. These F-actin spikes protrude pore-free nuclear membranes, whereas the adjoining membrane stretches accumulate NPCs associated with the still-intact lamina. Packed NPCs sort into a distinct membrane network, while breaks appear in ER-like, pore-free regions. Thereby, we reveal a new function for actin-mediated membrane shaping in nuclear rupture that is likely to have implications in other contexts such as nuclear rupture observed in cancer cells

Theory of Low Temperature Electron Spin Resonance in Half-integer Spin Antiferromagnetic Chains

A theory of low temperature (T) electron spin resonance (ESR) in half-integer spin antiferromagnetic chains is developed using field theory methods and avoiding previous approximations. It is compared to experiments on Cu benzoate. Power laws are predicted for the line-width broadening due to various types of anisotropy. At T -> 0, zero width absorption peaks occur in some cases. The second ESR peak in Cu benzoate, observed at T<.76K, is argued not to indicate Neel order as previously claimed, but to correspond to a sine-Gordon "breather" excitation.Comment: 4 pages, REVTEX, 3 PostScript figures embedded in tex

Qualidade do trigo brasileiro - safra 2002.

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Qualidade do trigo brasileiro - safra 2003.

Qualidade do trigo brasileiro - safra 2003; Introdução; Organização e método; Estados de abrangência - safra 2003: Bahia, Goiás, Mato Grosso do Sul, Minas Gerais, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul; Glossário; Aspectos relacionados à legislação; Informações sobre cultivares de trigo brasileiro.bitstream/item/84205/1/CNPT-DOC.-45-04.pd

Qualidade comercial do trigo brasileiro: safra 2006.

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First-Principles Study of Electronic Structure in α\alpha-(BEDT-TTF)2_2I3_3 at Ambient Pressure and with Uniaxial Strain

Within the framework of the density functional theory, we calculate the electronic structure of $\alpha$-(BEDT-TTF)$_2$I$_3$ at 8K and room temperature at ambient pressure and with uniaxial strain along the $a$- and $b$-axes. We confirm the existence of anisotropic Dirac cone dispersion near the chemical potential. We also extract the orthogonal tight-binding parameters to analyze physical properties. An investigation of the electronic structure near the chemical potential clarifies that effects of uniaxial strain along the a-axis is different from that along the b-axis. The carrier densities show $T^2$ dependence at low temperatures, which may explain the experimental findings not only qualitatively but also quantitatively.Comment: 10 pages, 7 figure

Direct observation of the proliferation of ferroelectric loop domains and vortex-antivortex pairs

We discovered "stripe" patterns of trimerization-ferroelectric domains in hexagonal REMnO3 (RE=Ho, ---, Lu) crystals (grown below ferroelectric transition temperatures (Tc), reaching up to 1435 oC), in contrast with the vortex patterns in YMnO3. These stripe patterns roughen with the appearance of numerous loop domains through thermal annealing just below Tc, but the stripe domain patterns turn to vortex-antivortex domain patterns through a freezing process when crystals cross Tc even though the phase transition appears not to be Kosterlitz-Thouless-type. The experimental systematics are compared with the results of our six-state clock model simulation and also the Kibble-Zurek Mechanism for trapped topological defects

Possible horizontal transfer of two subclasses of Mutator-like elements within Poaceae

Dissertação de mestrado em Gestão da Formação e Administração Educacional (Organizações Educativas e Gestão Escolar), apresentada à Faculdade de Psicologia e de Ciências da Educação da Universidade de CoimbraA presente dissertação é resultado de uma investigação realizada num Agrupamento de Escolas na zona Centro que obteve uma melhoria entre o primeiro e o segundo ciclo de avaliação externa de escolas. Centra-se na liderança praticada nas organizações escolares e na relação entre a melhoria das escolas com o Programa de Avaliação Externa de Escolas, com vista a compreender o papel das lideranças na melhoria de uma organização. A avaliação externa de escolas tem-se tornado indispensável para a criação de mecanismos de regulação que, de forma integrada com o processo de autoavaliação realizado pelas escolas desenvolvem novas práticas e, consequentemente, implementam processos de melhoria, visíveis pelas tomadas de decisão dos líderes das escolas. Com vista a verificar o que as lideranças do agrupamento têm feito para melhorar os resultados dos alunos, a prestação do serviço educativo e a capacidade de autoavaliação e melhoria desde a primeira avaliação externa, optámos pela metodologia de estudo de caso, procurando conjugar técnicas de natureza quantitativa e qualitativa. Neste sentido, recorremos à análise dos documentos estruturantes do Agrupamento de Escolas (Projeto Educativo, Regulamento Interno, Plano Anual de Atividades, Plano de Melhoria, Relatórios de Avaliação externa e Contraditório), à realização de entrevistas com o Diretor e com a Coordenadora da Equipa de Autoavaliação e, por fim, à elaboração e administração de um questionário para conhecer as perspetivas dos docentes sobre o funcionamento e o desempenho do Agrupamento de Escolas, bem como sobre as mudanças ocorridas na sequência da avaliação externa de escolas (AEE). Este estudo salienta que o papel de uma liderança efetiva e reconhecida é parte fundamental no desenvolvimento de uma organização e que a Avaliação Externa de Escolas é sentida e vivenciada pela organização em estudo, e ao ser conjugada com os dispositivos de reflexão interna e de autoavaliação, incentiva ao aperfeiçoamento dos planos de melhoria, encaminhando o Agrupamento para a melhoria contínua da qualidade do seu serviço educativo.The following dissertation is the result of an investigation in a School’s Division from center area of Portugal that has improved consederably its results in the first and second level of the External Evaluation of Schools. Its main focus is on the leadership of the Schools Organizations and the relationship between the Schools Improvement and the External Evaluation Program from Schools, taking in consideration the role of leadership in the improvement of an Organization. The external evaluation of schools has become, without doubt, necessary to create regulamentation mechanisms in order that schools could develop new cope ways and therefore, to implement and establish netter working processes, acknowledged by the schools chairmen and directors. With the main interes of checking the School’s Division’s Leadership and their work to improve the capability of self-evaluation, we opted to user a methodological study over quality and quantity. In this matter we chose to study and analyse the School’s Division documents, such as Educative Projects, Internal Regulation, Activities Annual Planification, Effort Planification and External Evaluation Reports. We also took action in interviewing School Directors, the self-evaluation Team Coordinator and foremost to create and practice a questionnaire to acknowledge the teacher’s perspectives about School’s Division maintenance and development, as well as the School’s External Evaluation . This study case empathizes the role of an effective and recognised leadership. It’s essential and crucial to the welfare and development of an organisation and the External School’s Evaluation is taken in great consideration by our study case. Moreover, dued to the self-evaluation system and combined with internal reflection devices it enhances the leadership’s accuracy in the quality improvement.La dissertation suivante est le résultat d'une investigation réalisée sur un ensemble d'écoles de la région centre du pays dont on a observé une amélioration entre le premier et le second cycle de l'évaluation externe des écoles. Elle porte sur la direction des organisations scolaires et le lien avec l'amélioration apportée aux écoles participant au programme d'évaluation externe des écoles. Elle vise ainsi à comprendre le rôle des directions dans la progression d'une institution. L'évaluation externe des écoles est devenue indispensable à la création de mécanismes de régulation, qui, intégrés au processus d'auto évaluation réalisée par l’école, permettent de développer de nouvelles méthodes. C'est ainsi par conséquent que sont mis en place des systèmes d'amélioration, rendus visibles grâce aux prises de décision des responsables désignés de l’établissement scolaire. Dans le but de vérifier la stratégie adoptée par les directions dans l’amélioration des résultats scolaire des élèves, la qualité du service éducatif et la capacité d’auto-évaluation depuis la première évaluation externe, nous choisirons de présenter ce travail à travers une étude de cas, cherchant ainsi à concilier des méthodes à la fois quantitative et qualitative. Ainsi, nous avons recours à une analyse de documents d’ordre organisationnel de l’ensemble scolaire (projet éducatif, règlement intérieur, plan annuel d’activités, plan d’amélioration, comptes rendus de l’évaluation externe et contradictoire), à la réalisation de rencontres avec le directeur et la coordinatrice de l’équipe d’autoévaluation et, enfin, à l’élaboration d’un questionnaire visant à connaitre les projets à venir dans le futur fonctionnement et l’investissement de l’ensemble d’écoles, tout comme dans les changements réalisés dans la séquence d’évaluation externe des écoles. Cette étude démontre que, le rôle d’une direction effective et reconnue est fondamentale dans le développement d’une organisation; et que l’évaluation externe des écoles prend tout son sens dans l’ensemble d’étude. De plus, l’ajout des dispositifs de réflexion interne et d’autoévaluation, facilite grandement le perfectionnement des plans d’amélioration, permettant ainsi l’amélioration constante et continue de la qualité du service éducatif de cet ensemble scolaire