940 resultados para Super-Reflexive


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We investigate the stability of super-Earth atmospheres around M stars using a seven-parameter, analytical framework. We construct stability diagrams in the parameter space of exoplanetary radius versus semimajor axis and elucidate the regions in which the atmospheres are stable against the condensation of their major constituents, out of the gas phase, on their permanent nightside hemispheres. We find that super-Earth atmospheres that are nitrogen-dominated (Earth-like) occupy a smaller region of allowed parameter space, compared to hydrogen-dominated atmospheres, because of the dual effects of diminished advection and enhanced radiative cooling. Furthermore, some super-Earths which reside within the habitable zones of M stars may not possess stable atmospheres, depending on the mean molecular weight and infrared photospheric pressure of their atmospheres. We apply our stability diagrams to GJ 436b and GJ 1214b, and demonstrate that atmospheric compositions with high mean molecular weights are disfavored if these exoplanets possess solid surfaces and shallow atmospheres. Finally, we construct stability diagrams tailored to the Kepler data set, for G and K stars, and predict that about half of the exoplanet candidates are expected to harbor stable atmospheres if Earth-like conditions are assumed. We include 55 Cancri e and CoRoT-7b in our stability diagram for G stars

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If we postulate a need for the transformation of society towards sustainable development, we also need to transform science and overcome the fact/value split that makes it impossible for science to be accountable to society. The orientation of this paradigm transformation in science has been under debate for four decades, generating important theoretical concepts, but they have had limited impact until now. This is due to a contradictory normative science policy framing that science has difficulties dealing with, not least of all because the dominant framing creates a lock-in. We postulate that in addition to introducing transdisciplinarity, science needs to strive for integration of the normative aspect of sustainable development at the meta-level. This requires a strategically managed niche within which scholars and practitioners from many different disciplines can engage in a long-term common learning process, in order to become a “thought collective” (Fleck) capable of initiating the paradigm transformation. Arguing with Piaget that “decentration” is essential to achieve normative orientation and coherence in a learning collective, we introduce a learning approach—Cohn's “Theme-Centred Interaction”—which provides a methodology for explicitly working with the objectivity and subjectivity of statements and positions in a “real-world” context, and for consciously integrating concerns of individuals in their interdependence with the world. This should enable a thought collective to address the epistemological and ethical barriers to science for sustainable development.

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Diverticulitis is a common disease in western countries and its incidence is increasing especially among young patients. Colonic diverticulosis, incidentally diagnosed by endoscopy or CT-scanning, has no immediate clinical consequences. Progression to diverticulitis develops in only 4 % of cases. In the last decades management of diverticular disease evolved and expectative treatment and less invasive techniques have gained importance. Elective resection has traditionally been advised after a second episode of diverticulitis or after a first episode if the patient was less than 50 years of age or complicated disease occurred. Recent changes in understanding the natural history of diverticular disease have substantially modified treatment paradigms. Elective resection in case of recurrent diverticular disease should be performed on a individual basis and in cases with complications like intestinal obstruction or fistulas. Primary anastomosis is an option even in emergency surgery due to colonic perforation, while diverting operations are indicated for selected patient groups with a high risk profile. Several prospective studies showed good results for laparoscopic drainage and lavage in the setting of perforated diverticulitis with generalized peritonitis, though this concept needs to be controlled with randomized clinical trials before application into the daily practice. This article should provide a short overview of trends in the surgical treatment of diverticulitis, help to understand the natural history of the disease and thereby explain the currently lower frequency of surgical interventions for diverticulitis.

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Vorbesitzer: Johannes de Lorch; Karmeliterkloster Frankfurt am Main

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Vorbesitzer: Bartholomaeusstift Frankfurt am Main

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Vorbesitzer: Bartholomaeusstift Frankfurt am Main

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Vorbesitzer: Johannes Oppeler de Butzbach; Bartholomaeusstift Frankfurt am Main