Giant monopole resonance and nuclear compression modulus for 40Ca and 16O

Using a collective potential derived on the basis of the Generator Coordinate Method with Skyrme interactions we obtain values for the compression modulus of 40Ca which are in good agreement with a recently obtained experimental value. Calculated values for the compression modulus for 16O are also given. The procedure involved in the derivation of the collective potential is briefly reviewed and discussed.Comment: 14 pages, no figures, two tables, REVTE

Run-Time Selection of Coordination Mechanisms in Multi-Agent Systems

This paper presents a framework that enables autonomous agents to dynamically select the mechanism they employ in order to coordinate their inter-related activities. Adopting this framework means coordination mechanisms move from the realm of being imposed upon the system at design time, to something that the agents select at run-time in order to fit their prevailing circumstances and their current coordination needs. Empirical analysis is used to evaluate the effect of various design alternatives for the agent's decision making mechanisms and for the coordination mechanisms themselves

Time Evolution of tunneling and decoherence: soluble model

Decoherence effects associated to the damping of a tunneling two-level system are shown to dominate the tunneling probability at short times in strong coupling regimes in the context of a soluble model. A general decomposition of tunneling rates in dissipative and unitary parts is implemented. Master equation treatments fail to describe the model system correctly when more than a single relaxation time is involved

Lipid Bodies: Inflammatory Organelles Implicated in Host-Trypanosoma cruzi Interplay during Innate Immune Responses

The flagellated protozoa Trypanosoma cruzi is the causal agent of Chagas' disease, a significant public health issue and still a major cause of morbidity and mortality in Latin America. Acute Chagas' disease elicits a strong inflammatory response. In order to control the parasite multiplication, cells of the monocytic lineage are highly mobilized. Monocyte differentiation leads to the formation of phagocytosing macrophages, which are strongly activated and direct host defense. A distinguishing feature of Chagas' disease-triggered macrophages is the presence of increased numbers of distinct cytoplasmic organelles termed lipid bodies or lipid droplets. These organelles are actively formed in response to the parasite and are sites for synthesis and storage of inflammatory mediators. This review covers current knowledge on lipid bodies elicited by the acute Chagas' disease within inflammatory macrophages and discusses the role of these organelles in inflammation. The increased knowledge of lipid bodies in pathogenic mechanisms of infections may not only contribute to the understanding of pathogen-host interactions but may also identify new targets for intervention

Análise dos Procedimentos de Ensino Utilizados no Curso de Odontologia da Universidade Federal do Espírito Santo

O processo de ensino-aprendizagem vem passando por muitas mudanças ao longo dos anos, um dos motivos é buscar adaptar-se à geração de estudantes das escolas e universidades. Essa adaptação vem ocorrendo também no currículo dos cursos de nível superior, dentre eles, a Odontologia. Uma forma de registrar tais mudanças é a análise do projeto pedagógico dos cursos (PPC) de Odontologia. No PPC existem informações vitais e importantes sobre o objetivo do curso, disciplinas cursadas (obrigatórias e optativas), bem como os procedimentos de ensino que os docentes estão utilizando para dar aulas. O objetivo foi verificar os procedimentos de ensino registrados no PPC do curso de Odontologia da Universidade Federal do Espírito Santo (UFES) e comparar com os procedimentos de ensino citados pelos docentes que atuam no ciclo profissionalizante, por meio de entrevista (questionário). Foi realizado um estudo documental, exploratório, descritivo e de natureza quantitativa. Na pesquisa documental do PPC foram incluídas 50% das disciplinas do ciclo profissionalizante (5º ao 10º período), totalizando 15 disciplinas. A seguir, foram entrevistados os docentes do ciclo profissionalizante do curso de Odontologia da UFES (5º ao 10º período) de três departamentos: Clínica Odontológica, Prótese Dentária e Medicina Social, que foram selecionados aleatoriamente. O procedimento de ensino mais frequentemente citado pelos docentes foi a aula expositiva (93%), seguido do seminário (40%). No PPC o procedimento de ensino registrado mais frequentemente foi o seminário (91%), seguido da aula expositiva (83%). Outros seis procedimentos de ensino foram citados pelos docentes e registrados no PPC, dentre eles a pesquisa bibliográfica, aprendizado baseado em problema (ABP), estudo dirigido, grupo de estudo, discussão e problematização. Foi observado nessa pesquisa que existe pouca diversidade nos procedimentos de ensino citados pelos docentes entrevistados e descritos no PPC de Odontologia da UFES. Pode-se concluir que existe alguma dificuldade ou deficiência pedagógica por parte dos docentes entrevistados para adotar novos procedimentos de ensino, incluindo os procedimentos de ensino interativos

Proton fraction in the inner neutron-star crust

Monte Carlo simulations of neutron-rich matter of relevance to the inner neutron-star crust are performed for a system of A=5,000 nucleons. To determine the proton fraction in the inner crust, numerical simulations are carried out for a variety of densities and proton fractions. We conclude---as others have before us using different techniques---that the proton fraction in the inner stellar crust is very small. Given that the purported "nuclear pasta" phase in stellar crusts develops as a consequence of the long-range Coulomb interaction among protons, we question whether pasta formation is possible in such proton-poor environments. To answer this question, we search for physical observables sensitive to the transition between spherical nuclei and exotic pasta structures. Of particular relevance is the static structure factor S(k)---an observable sensitive to density fluctuations. However, no dramatic behavior was observed in S(k). We regard the identification of physical observables sensitive to the existence---or lack-thereof---of a pasta phase in proton-poor environments as an open problem of critical importance.Comment: 24 pages and 7 figure

Three-dimensional image surface acquisition in vertebrate paleontology: A review of principal techniques

Three-dimensional (3D) surface scanning includes techniques of image acquisition and image processing. Among the former, hardware devices (e.g., portable and non-portable scanners, camera) capture images from the target, whereas image processing is conducted via specialized software, in which acquired images are processed to merge them into a single 3D surface model. Image surface scanning comprises a wide variety of devices which incorporate different image acquisition techniques, all of them with potential high standards results. We describe four different scanning devices and techniques commonly used in vertebrate paleontology in order to compare them in terms of pros and cons, considering different variables, such as scanning time, post-processing time, costs and image resolution. The decision on which device to choose will depend on the budget available, the portability as well as the nature of the fossil material being analyzed (e.g., size, weight, accessibility). In the light of this, photogrammetry constitutes the image surface technique which fulfills these requirements, having the best cost-benefit relationship

Fine Structure Discussion of Parity-Nonconserving Neutron Scattering at Epithermal Energies

The large magnitude and the sign correlation effect in the parity non-conserving resonant scattering of epithermal neutrons from $^{232}$Th is discussed in terms of a non-collective $2p-1h$ local doorway model. General conclusions are drawn as to the probability of finding large parity violation effects in other regions of the periodic table.Comment: 6 pages, Tex. CTP# 2296, to appear in Z. Phys.

Light echoes reveal an unexpectedly cool Eta Carinae during its 19th-century Great Eruption

Eta Carinae (Eta Car) is one of the most massive binary stars in the Milky Way. It became the second-brightest star in the sky during its mid-19th century "Great Eruption," but then faded from view (with only naked-eye estimates of brightness). Its eruption is unique among known astronomical transients in that it exceeded the Eddington luminosity limit for 10 years. Because it is only 2.3 kpc away, spatially resolved studies of the nebula have constrained the ejected mass and velocity, indicating that in its 19th century eruption, Eta Car ejected more than 10 M_solar in an event that had 10% of the energy of a typical core-collapse supernova without destroying the star. Here we report the discovery of light echoes of Eta Carinae which appear to be from the 1838-1858 Great Eruption. Spectra of these light echoes show only absorption lines, which are blueshifted by -210 km/s, in good agreement with predicted expansion speeds. The light-echo spectra correlate best with those of G2-G5 supergiant spectra, which have effective temperatures of ~5000 K. In contrast to the class of extragalactic outbursts assumed to be analogs of Eta Car's Great Eruption, the effective temperature of its outburst is significantly cooler than allowed by standard opaque wind models. This indicates that other physical mechanisms like an energetic blast wave may have triggered and influenced the eruption.Comment: Accepted for publication by Nature; 4 pages, 4 figures, SI: 6 pages, 3 figures, 5 table