2,949 research outputs found

    Spin crossover transition driven by pressure: Barocaloric applications

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    This article describes a mean-field theoretical model for Spin-Crossover (SCO) materials and explores its implications. It is based on a simple Hamiltonian that yields the high spin molar fraction as a function of temperature and pressure, as well as a temperature-pressure phase diagram for the SCO transition. In order to test the model, we apply it to the giant Barocaloric Effect (BCE) of the SCO material [FeL2_2][BF4_4]2_2 and comprehensively analyse its behavior. We found that optical phonons are responsible for 92\% of the total barocaloric entropy change. DFT calculations show that these optical phonons are mainly assigned to the low frequencies modes of vibration (<400<400 cm1^{-1}), being associated to the Fe coordination.Comment: 6 figure

    Articulação entre os conhecimentos tácito e científico na operação de sistemas digitais em plantas de refino : um estudo de caso

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    Orientadora: Izaura Hiroko KuwabaraDissertação (mestrado) - Universidade Federal do Paraná, Setor de Educação, Programa de Pós-Graduação em Educação. Defesa: Curitiba, 2005Inclui bibliografia e anexosResumo: A partir da revolução técnico-científica, a aplicação da ciência à produção vem sendo intensificada. Desde então, algumas das novas indústrias que emergiram passaram a exigir um tipo diferente de trabalhador; alguém que necessitasse articular teoria e prática no seu processo de trabalho. Como uma de suas conseqüências, tal fato tem gerado a transformação das formas de articulação entre o conhecimento tácito e o conhecimento científico dos trabalhadores. Neste estudo analisa-se como uma das mais recentes aplicações da ciência à produção - a mudança da base eletromecânica para a base microeletrônica - afetou a forma de articulação entre o conhecimento tácito e o conhecimento científico dos operadores de processo da Refinaria Getúlio Vargas - Repar. Esta análise permitiu apontar que as mudanças tecnológicas por si só não transformam o trabalho e o trabalhador. São necessárias mudanças profundas nas relações sociais de produção para avançar da prática à práxis.Abstract: Since the technical-scientific revolution the application of science to the production comes being intensified. Some of the new industries that had emerged, they had started to demand a different kind of worker; somebody that it needs to articulate practical and theory in its process of work. Such fact has generated the transformation of the forms of joint between the tacit knowledge and the scientific knowledge of the workers, as one of its consequences. In our study we analyze as one of the most recent applications of science to the production, the change of the electromechanical base for the base microelectronics, it affected the form of joint between the tacit knowledge and the scientific knowledge of the operators of process of the Refinaria Getúlio Vargas - Repar. Our analysis allowed to point that the technological changes by itself do not transform the work and the worker. There are necessary deep changes in the social relations of production to advance of the practical one to the praxis

    Safety and tolerability of antipsychotics: focus on amisulpride

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    The introduction of the atypical antipsychotic drugs represents an important advance in the treatment of schizophrenia, because the therapeutic efficacy, tolerability, and safety profiles of these agents seem to be superior to that of the classical neuroleptics. As would be predicted from the pharmacologic profile of a pure D2/D3 receptor blocker, amisulpride is an atypical antipsychotic agent, effective for positive and negative symptoms, which can bring about additional improvement in the social functioning and quality of life of patients with schizophrenia. Amisulpride is effective in acute schizophrenia as determined by Clinical Global Impression scores. The major concern regarding the safety of the atypical antipsychotics is related to their propensity to induce weight gain and alter glucose and lipid metabolism. Amisulpride has one of the lowest potentials for weight gain of all the antipsychotic agents, and is associated with clearly lower use of antiparkinsonian medication and with fewer dropouts due to adverse events than conventional antipsychotics. Amisulpride is well tolerated with regard to anxiety and insomnia, and not notably different from placebo. Amisulpride has a pronounced prolactin-elevating effect which appears to be independent of dosage and duration of administration. Hyperprolactinemia rapidly reverses following amisulpride discontinuation. Amisulpride benefits patients with negative symptoms, and is the only antipsychotic to demonstrate efficacy in patients with predominantly negative symptoms. Amisulpride maintains its efficacy when used for medium/long-term treatment, as demonstrated in studies of up to 12 months. In terms of relevance of the effects, superiority is observed for quality of life, social adaptation, and functioning, as measured by the Quality of Life and Functional Status Questionnaire scales. In conclusion, amisulpride is an antipsychotic agent with proven efficacy and good tolerability. Moreover, this drug can help people with schizophrenia to attain social reinsertion

    Gardnerella vaginalis enhances Atopobium vaginae viability in an in vitro Model

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    Bacterial vaginosis (BV) is the most common vaginal infection among women of reproductive age. A hallmark of BV is the presence of a highly structured polymicrobial biofilm on the vaginal epithelium, presumably initiated by facultative anaerobes of the genus Gardnerella, which then becomes a scaffold for other species to adhere to. One of the species often found incorporated in Gardnerella mediated biofilms is Atopobium vaginae. Interestingly, A. vaginae is very rarely found without the presence of Gardnerella. However, not much is known regarding the interactions between A. vaginae and Gardnerella species. This study assessed biological interactions between Gardnerella vaginalis and A. vaginae. In our in vitro model, by using specific Gardnerella and A. vaginae Peptide Nucleic Acid (PNA)-Fluorescence In Situ Hybridization (FISH) probes, we confirmed that A. vaginae was able to incorporate a pre-formed G. vaginalis biofilm, accounting for up to 20% of the total number of biofilm cells. However, our findings showed that almost 92% of A. vaginae cells lost viability after 48 h of mono-species planktonic growth, but were able to maintain viability when co-cultured with Gardnerella or after pre-conditioning with cell-free supernatant of Gardnerella cultures. While the in vitro conditions are very different from the in vivo microenvironment, this study contributes to a better understanding of why A. vaginae vaginal colonization rarely occurs in the absence of Gardnerella. Overall, this highlights the importance of microbial interactions between BV-associated bacteria and demands more studies focused on the polymicrobial bacterial communities found in BV.This work was supported by the research project [PTDC/BIAMIC/28271/2017] under the scope of COMPETE 2020 [POCI-01-0145-FEDER-028271], supported by the Portuguese Foundation for Science and Technology (FCT), and by the strategic funding of unit [UID/BIO/04469/2019]. AR acknowledges the financial support of individual Grant [PD/BD/128037/2016].info:eu-repo/semantics/publishedVersio

    Neither phylogenomic nor palaeontological data support a Palaeogene origin of placental mammals.

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    O'Leary et al. (O'Leary et al. 2013 Science 339, 662-667. (doi:10.1126/science.1229237)) performed a fossil-only dating analysis of mammals, concluding that the ancestor of placentals post-dated the Cretaceous-Palaeogene boundary, contradicting previous palaeontological and molecular studies that placed the ancestor in the Cretaceous. They incorrectly used fossil ages as species divergence times for crown groups, while in fact the former should merely form minimum-age bounds for the latter. Statistical analyses of the fossil record have shown that crown groups are significantly older than the oldest ingroup fossil, so that fossils do not directly reflect the true ages of clades. Here, we analyse a 20 million nucleotide genome-scale alignment in conjunction with a probabilistic interpretation of the fossil ages from O'Leary et al. Our combined analysis of fossils and molecules demonstrates that Placentalia originated in the Cretaceous.This work was financially supported by BBSRC grant no. BB/J009709/1

    On the statistics of area size in two-dimensional thick Voronoi Diagrams

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    Cells of Voronoi diagrams in two dimensions are usually considered as having edges of zero width. However, this is not the case in several experimental situations in which the thickness of the edges of the cells is relatively large. In this paper, the concept of a thick Voronoi tessellation, that is with edges of non-zero width, is introduced and the the statistics of cell areas, as thickness changes, are analyzed.Comment: 14 pages, 9 figure

    Uncertainty in the Timing of Origin of Animals and the Limits of Precision in Molecular Timescales

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    The timing of divergences among metazoan lineages is integral to understanding the processes of animal evolution, placing the biological events of species divergences into the correct geological timeframe. Recent fossil discoveries and molecular clock dating studies have suggested a divergence of bilaterian phyla >100 million years before the Cambrian, when the first definite crown-bilaterian fossils occur. Most previous molecular clock dating studies, however, have suffered from limited data and biases in methodologies, and virtually all have failed to acknowledge the large uncertainties associated with the fossil record of early animals, leading to inconsistent estimates among studies. Here we use an unprecedented amount of molecular data, combined with four fossil calibration strategies (reflecting disparate and controversial interpretations of the metazoan fossil record) to obtain Bayesian estimates of metazoan divergence times. Our results indicate that the uncertain nature of ancient fossils and violations of the molecular clock impose a limit on the precision that can be achieved in estimates of ancient molecular timescales. For example, although we can assert that crown Metazoa originated during the Cryogenian (with most crown-bilaterian phyla diversifying during the Ediacaran), it is not possible with current data to pinpoint the divergence events with sufficient accuracy to test for correlations between geological and biological events in the history of animals. Although a Cryogenian origin of crown Metazoa agrees with current geological interpretations, the divergence dates of the bilaterians remain controversial. Thus, attempts to build evolutionary narratives of early animal evolution based on molecular clock timescales appear to be premature
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