Die Massenmedien im Leben der Schüler. Ergebnisse einer Untersuchung im Kanton Zürich

Obwohl die Massenmedien, davon insbesondere das Fernsehen, allem Anschein nach eine zentrale Stellung im Leben der heutigen Schüler einnehmen, hat man bis jetzt in Deutschland und der Schweiz kaum wissenschaftlich untersucht, warum sie die Massenmedien so intensiv nutzen und mit welchen Folgen. Die Diskussion um Einfluss und Funktionen der verschiedenen Medien auf die Jugendlichen im Spannungsfeld der Sozialisationsinstanzen Schule, Familie und Kameraden wird vielmehr vorwiegend von engagierten Laien geführt, die entsprechend ihrer Aktivität für Schule, Kirche, Politik, Wirtschaft oder für den Medienbereich selber von Vorurteilen nicht frei sind und überdies allzuoft einseitig nur das Leitmedium Fernsehen anvisieren. Von den Eltern wiederum werden die Massenmedien aufgrund alltagsweltlicher Vorstellungen über direkte Medienwirkungen oft negativ bewertet; auf den eigenen Medienkonsum wollen und können sie aber nicht verzichten und laufen so Gefahr, auf ihre Kinder unglaubwürdig zu wirken. Für Pädagogen und Lehrer als Vertreter des offiziellen Bildungssystems mit entsprechenden Normen und Wertvorstellungen stellen schliesslich die Medien insofern eine Bedrohung dar, als diese alternative oder sogar gegensätzliche Sozialisationsinhalte anbieten, die dem Schüler zudem oft attraktiver scheinen als der Schulstoff. Weil also insgesamt das eigene Verhältnis zu den Massenmedien ambivalent ist, fordert man denn auch von der Wissenschaft immer wieder Verhaltensanweisungen und praktische Rezepte, ja, verlangt von ihr eine klare Auskunft bezüglich der globalen Frage: Sind die Medien gut oder schlecht für die Schulkinder

Tree functional diversity affects litter decomposition and arthropod community composition in a tropical forest

Disturbance can alter tree species and functional diversity in tropical forests, which in turn could affect carbon and nutrient cycling via the decomposition of plant litter. However, the influence of tropical tree diversity on forest floor organisms and the processes they mediate are far from clear. We investigated the influence of different litter mixtures on arthropod communities and decomposition processes in a 60-year-old lowland tropical forest in Panama, Central America. We used litter mixtures representing pioneer and old growth tree species in experimental mesocosms to assess the links between litter types, decomposition rates, and litter arthropod communities. Overall, pioneer species litter decomposed most rapidly and old growth species litter decomposed the slowest but there were clear non-additive effects of litter mixtures containing both functional groups. We observed distinct arthropod communities in different litter mixtures at 6 mo, with greater arthropod diversity and abundance in litter from old growth forest species. By comparing the decay of different litter mixtures in mesocosms and conventional litterbags, we demonstrated that our mesocosms represent an effective approach to link studies of litter decomposition and arthropod communities. Our results indicate that changes in the functional diversity of litter could have wider implications for arthropod communities and ecosystem functioning in tropical forests

Das Abstimmungsproblem bei drei Alternativen. Versuch einer systematischen Klärung

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Der Begriff der Therapieresistenz bei unipolaren depressiven Störungen aus medizinischer und aus rechtlicher Sicht – eine Standortbestimmung im Nachgang zu BGE 9C_13/2016

Der Beitrag befasst sich mit der bundesgerichtlichen Rechtsprechung zur allfälligen invalidisierenden Wirkung bestimmter depressiver Störungen. Dabei steht für das Bundesgericht im Zentrum, ob die betreffende Einschränkung therapieresistent ist. Das Bundesgericht legt dar, dass es sich um seltene Konstellationen handle, in denen bei Depressionen leichter oder mittelgradiger Natur eine Therapieresistenz bestehe. Im Beitrag wird aus medizinischer Sicht eine Definition der chronischen depressiven Störung und der therapieresistenten Depression gegeben. Dabei wird genau untersucht, wann eine Therapieresistenz angenommen werden muss. Bei chronischen Verläufen mit einer z.T. mehrjährigen Krankheitsdauer kann aus medizinischer Sicht nicht mehr mehrheitlich von einer günstigen Prognose ausgegangen werden. Mindestens in 40% dieser chronifizierten Fälle besteht eine echte Therapieresistenz

A world-wide study of high altitude treeline temperatures

Aim At a coarse scale, the treelines of the world`s mountains seem to follow a common isotherm, but the evidence for this has been indirect so far. Here we aim at underpinning this with facts. Location We present the results of a data-logging campaign at 46 treeline sites between 68degrees N and 42degrees S. Methods We measured root-zone temperatures with an hourly resolution over 1-3 years per site between 1996 and 2003. Results Disregarding taxon-, landuse- or fire-driven tree limits, high altitude climatic treelines are associated with a seasonal mean ground temperature of 6.7 degreesC (+/-0.8 SD; 2.2 K amplitude of means for different climatic zones), a surprisingly narrow range. Temperatures are higher (7-8 degreesC) in the temperate and Mediterranean zone treelines, and are lower in equatorial treelines (5-6 degreesC) and in the subarctic and boreal zone (6-7 degreesC). While air temperatures are higher than soil temperatures in warm periods, and are lower than soil temperatures in cold periods, daily means of air and soil temperature are almost the same at 6-7 degreesC, a physics driven coincidence with the global mean temperature at treeline. The length of the growing season, thermal extremes or thermal sums have no predictive value for treeline altitude on a global scale. Some Mediterranean (Fagus spp.) and temperate South Hemisphere treelines (Nothofagus spp.) and the native treeline in Hawaii (Metrosideros) are located at substantially higher isotherms and represent genus-specific boundaries rather than boundaries of the life-form tree. In seasonal climates, ground temperatures in winter (absolute minima) reflect local snow pack and seem uncritical. Main conclusions The data support the hypothesis of a common thermal threshold for forest growth at high elevation, but also reflect a moderate region and substantial taxonomic influence

Relação entre qualidade e liberação de N por plantas do semiárido usadas como adubo verde Relationship between biomass quality and N mineralization in plant species used as green manure in semi-arid Brazil

O uso de plantas como adubo verde pode ser uma alternativa para melhorar a fertilidade do solo porém a liberação de nutrientes desses adubos para o solo irá depender dos teores de lignina, polifenóis (PP) e N no material vegetal utilizado. Tais teores foram determinados em 24 espécies vegetais encontradas em propriedades rurais do semiárido e relacionados com a mineralização de N, quando incorporados ao solo. Os materiais apresentaram grande variação nos teores os quais, por sua vez, sinalizaram baixa correlação com as proporções do N mineralizado depois da incorporação. Utilizando os teores e suas relações, realizou-se análise de componentes principais agrupando os materiais de acordo com suas similaridades, visando verificar a existência de relações entre a formação dos grupos referidos e o N mineralizado após incubação dos materiais orgânicos. Quatro grupos foram formados; no entanto, pouca informação útil foi gerada no sentido de tentar predizer a mineralização de N com base na qualidade dos materiais testados. O comportamento da lignina não foi bem definido na formação dos grupos e não apresentou relação clara com a mineralização do N devido, talvez, ao curto prazo de avaliação da metodologia adotada (28 dias). Todos os materiais que apresentaram relação PP/N menor que 0,5, mineralizaram N enquanto que os apresentaram a mesma relação acima de 5, imobilizaram N.<br>The use of plants as green manure may be an alternative to improve soil fertility in the region, but the release of nutrients to the soil will depend on the concentrations of lignin, polyphenols (PP), and nitrogen of the green manures used. These variables were analyzed for 24 plant species commonly found in farms of the semi-arid region of NE Brazil, and the relationship between plant biomass quality and N release after incorporation into the soil was evaluated. There was a large variation in the concentration of lignin, PP and N of the green manures tested but these variables presented a low correlation with N mineralization after incorporation to the soil. In order to try to identify patterns among the different manures regarding quality and N release, these were grouped using Principal Component Analysis techniques, but very little meaningful patterns were observed to help predict N release based on the quality of the materials. The lignin content of the materials played an important role to form different groups, but may be the short time of the incubations (28 days) did not allow for the development of the correlation between lignin content and N release. In general, it was observed that all materials that presented a PP/N ratio lower than 0.5 mineralized N, while those that presented values of this ratio above 5 caused N immobilization