695 research outputs found

    High-resolution correlation of coastal cliff sections in the Lagos- Portimao Formation (Lower - Middle Miocene, central Algarve, Portugal)

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    This paper describes a high-resolution stratigraphic correlation scheme for the early to middle Miocene Lagos-Portimão Formation of central Algarve, southern Portugal. The Lagos Portimão-Formation of central Algarve is a 60 m thick package of horizontally bedded siliciclastics and carbonates. The bryozoan and mollusc dominated biofacies is typical of a shallow marine, warm-temperate climatic environment. We define four stratigraphic marker beds based on biofacies, lithology, and gamma-ray signatures. Marker bed 1 is a reddish shell bed composed predominantly of bivalve shells in various stages of fragmentation. Marker bed 2 is a fossiliferous sandstone / sandy rudstone characterized by bryozoan masses. Marker bed 3 is also a fossiliferous sandstone with abundant larger foraminifers and foliate bryozoans. Marker bed 4 is composed of three distinct layers; two fossiliferous sandstones with an intercalated shell bed. The upper sandstone unit displays thickets of the bryozoan Celleporaria palmate associated with the coral Culizia parasitica. This stratigraphic framework allows to correlate isolated outcrops within the stratigraphic context of the Lagos-Portimão Formation and to establish high resolution chronostratigraphic Sr-isotopic dating

    Gaussian excitations model for glass-former dynamics and thermodynamics

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    We describe a model for the thermodynamics and dynamics of glass-forming liquids in terms of excitations from an ideal glass state to a Gaussian manifold of configurationally excited states. The quantitative fit of this three parameter model to the experimental data on excess entropy and heat capacity shows that ``fragile'' behavior, indicated by a sharply rising excess heat capacity as the glass transition is approached from above, occurs in anticipation of a first-order transition -- usually hidden below the glass transition -- to a ``strong'' liquid state of low excess entropy. The dynamic model relates relaxation to a hierarchical sequence of excitation events each involving the probability of accumulating sufficient kinetic energy on a separate excitable unit. Super-Arrhenius behavior of the relaxation rates, and the known correlation of kinetic with thermodynamic fragility, both follow from the way the rugged landscape induces fluctuations in the partitioning of energy between vibrational and configurational manifolds. A relation is derived in which the configurational heat capacity, rather than the configurational entropy of the Adam Gibbs equation, controls the temperature dependence of the relaxation times, and this gives a comparable account of the experimental observations.Comment: 21 pp., 17 fig

    Bottlenecks to vibrational energy flow in OCS: Structures and mechanisms

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    Finding the causes for the nonstatistical vibrational energy relaxation in the planar carbonyl sulfide (OCS) molecule is a longstanding problem in chemical physics: Not only is the relaxation incomplete long past the predicted statistical relaxation time, but it also consists of a sequence of abrupt transitions between long-lived regions of localized energy modes. We report on the phase space bottlenecks responsible for this slow and uneven vibrational energy flow in this Hamiltonian system with three degrees of freedom. They belong to a particular class of two-dimensional invariant tori which are organized around elliptic periodic orbits. We relate the trapping and transition mechanisms with the linear stability of these structures.Comment: 13 pages, 13 figure

    Adaptive walks on time-dependent fitness landscapes

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    The idea of adaptive walks on fitness landscapes as a means of studying evolutionary processes on large time scales is extended to fitness landscapes that are slowly changing over time. The influence of ruggedness and of the amount of static fitness contributions are investigated for model landscapes derived from Kauffman's NKNK landscapes. Depending on the amount of static fitness contributions in the landscape, the evolutionary dynamics can be divided into a percolating and a non-percolating phase. In the percolating phase, the walker performs a random walk over the regions of the landscape with high fitness.Comment: 7 pages, 6 eps-figures, RevTeX, submitted to Phys. Rev.

    Electron attachment to SF6 and lifetimes of SF6- negative ions

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    We study the process of low-energy electron capture by the SF6 molecule. Our approach is based on the model of Gauyacq and Herzenberg [J. Phys. B 17, 1155 (1984)] in which the electron motion is coupled to the fully symmetric vibrational mode through a weakly bound or virtual s state. By tuning the two free parameters of the model, we achieve an accurate description of the measured electron attachment cross section and good agreement with vibrational excitation cross sections of the fully symmetric mode. An extension of the model provides a limit on the characteristic time of intramolecular vibrational relaxation in highly-excited SF6-. By evaluating the total vibrational spectrum density of SF6-, we estimate the widths of the vibrational Feshbach resonances of the long-lived negative ion. We also analyse the possible distribution of the widths and its effect on the lifetime measurements, and investigate nonexponential decay features in metastable SF6-.Comment: 22 pages, 10 figures, submitted to Phys. Rev.

    A educação na 'Constelação pós-nacional': o enfraquecimento da legitimação e do controle democrático, "expertocrático" e ético-profissional

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    The article discusses current transformations in the education systems worldwide. Focusing on the European Union (EU) and the Organisation for Economic Cooperation and Development (OECD) as policy actors, it argues that these transformations imply a triple economization of education policy which can be observed at all levels of the education sector. The increasing importance of these organizations in educational issues marks a transition to a "postnational constellation" also in the education field insofar as the national educational sovereignty is being at least readjusted. The economization of education policy is however not restricted to bringing education closer to the needs of the economy and to turning its services into tradable goods. Rather, it also impinges on the operative level of education. A logics of production is being implemented in the self-description of the institutions of the education system, which are no longer bureaucratically administered establishments, but are rather conceived of as managerially conducted production business in which entrepreneurial action is needed. This new governance raises the problem of democratic legitimation of political decisions which ideally combines three elements: democratic, expertocratic, and ethico-professional. The article discusses the consequences of a shift in the balance of the three components with reference to Germany.O presente artigo discute as atuais transformações nos sistemas educacionais em todo o mundo. Tendo como foco a União Europeia (UE) e a Organização para a Cooperação e o Desenvolvimento Econômico (OCDE) como atores de políticas, seu argumento é que tais transformações implicam uma tripla "economização" da política educacional, que pode ser constatada em todos os níveis da área educacional. A importância cada vez maior dessas organizações nas questões educacionais configura uma transição para uma "constelação pós-nacional" também na área educacional, na medida em que a soberania educacional nacional está, no mínimo, passando por reajustes. No entanto, a "economização" das políticas educacionais não se limita a aproximar a educação das necessidades da economia e a transformar seus serviços em mercadorias comercializáveis. Ela também afeta o nível operacional da educação. Uma lógica de produção está sendo implementada na descrição realizada pelas próprias instituições do sistema educacional, que deixaram de ser estabelecimentos burocraticamente administrados para ser concebidos como uma atividade comercial gerencialmente controlada, uma atividade na qual uma ação empresarial se faz necessária. Esse novo tipo de administração faz surgir o problema da legitimação democrática das decisões políticas que, em termos ideais, combina três elementos: o democrático, o "expertocrático" e o ético-profissional. O artigo discute as consequências de uma mudança no equilíbrio desses três elementos no caso da Alemanha

    Report from the CVOT Summit 2020: new cardiovascular and renal outcomes

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    The 6th Cardiovascular Outcome Trial (CVOT) Summit “Cardiovascular and Renal Outcomes 2020” was the first to be held virtually on October 29–30, 2020. As in previous years, this summit served as reference meeting for in-depth discussions on the topic of recently completed and presented major outcome trials. This year, focus was placed on the outcomes of VERTIS-CV, EMPEROR-Reduced, DAPA-CKD, and FIDELIO-DKD. Trial implications for diabetes management and the impact on new treatment algorithms were highlighted for diabetologists, cardiologists, endocrinologists, nephrologists, and general practitioners. Discussion evolved from major outcome trials using SGLT-2 inhibitors for treatment and prevention of heart failure and chronic kidney disease in people with and without diabetes, to additional therapy options for chronic kidney disease with a novel mineralocorticoid receptor antagonist. Furthermore, challenges in diabetes management like COVID-19 and obesity, as well as novel treatment strategies and guidelines, were discussed. The 7th Cardiovascular Outcome Trial Summit will be held virtually on November, 18–19, 2021 (http://www.cvot.org)

    Secretion of beta-human chorionic gonadotropin by non-small cell lung cancer: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>We describe a case of non-small cell lung cancer that was found to stain positive for beta-human chorionic gonadotropin on immunohistochemistry. Only a few case reports have described lung cancers that secrete beta-human chorionic gonadotropin.</p> <p>Case presentation</p> <p>A 68-year-old Caucasian man presented with symptoms of weakness, fatigue and weight loss for the past two months. On examination, he was found to have generalized lymphadenopathy, and radiologic workup revealed numerous metastases in the lungs, liver and kidneys. Biopsy of the supraclavicular lymph node revealed metastatic large cell lung cancer with beta-human chorionic gonadotropin hormone positivity. The serum beta-human chorionic gonadotropin level was 11,286 mIU/ml (upper limit of normal, 0.5 mIU/ml in non-pregnant females). He was diagnosed with stage 4 lung non-small cell lung cancer. The patient refused chemotherapy. He was discharged home with hospice care.</p> <p>Conclusion</p> <p>The markedly elevated serum values of beta-human chorionic gonadotropin initially prompted the medical team to investigate germinal tumors. In the presence of a negative testicular ultrasound, workup was performed to find an extratesticular source of the tumor. Finally, the diagnosis was made with a tissue biopsy. This case illustrates that atypical markers can be seen in many cancers, emphasizing the role of immunohistochemistry and tissue biopsy in establishing the diagnosis.</p

    Star Architecture as Socio-Material Assemblage

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    Taking inspiration from new materialism and assemblage, the chapter deals with star architects and iconic buildings as socio-material network effects that do not pre-exist action, but are enacted in practice, in the materiality of design crafting and city building. Star architects are here conceptualized as part of broader assemblages of actors and practices ‘making star architecture’ a reality, and the buildings they design are considered not just as unique and iconic objects, but dis-articulated as complex crafts mobilizing skills, technologies, materials, and forms of knowledge not necessarily ascribable to architecture. Overcoming narrow criticism focusing on the symbolic order of icons as unique creations and alienated repetitions of capitalist development, the chapter’s main aim is to widen the scope of critique by bridging culture and economy, symbolism and practicality, making star architecture available to a broad, fragmented arena of (potential) critics, unevenly equipped with critical tools and differentiated experiences
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