101 research outputs found

    About the participation of defoliators in the oak decline symptoms in Brandenburg 2004

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    Die Gefährdung der Eiche durch biotische Schaderreger ist in der einschlägigen Fachliteratur umfänglich beschrieben (u.a. PATOKA 1980, HARTMANN 1995, ALTENKIRCH et al. 2000). Im Jahr 2004 rückte die Fraßgesellschaft der Eiche im Zusammenhang mit den beobachteten „Austriebsdepressionen“ in den besonderen Fokus der Waldschutzüberwachung in Brandenburg. Im Mai 2004 gab es aus allen Ämtern für Forstwirtschaft Brandenburgs Meldungen über massive Austriebsstörungen, d.h. die Terminalknospen waren nur schwach entwickelt oder bereits abgestorben, nicht selten war die gesamte Triebspitze kaum noch lebensfähig. Die Untersuchung des Materials zeigte, dass keine primären pilzlichen Schaderreger und die Eichenfraßgesellschaft in unterschiedlichem Maß, zumeist aber mit sehr geringen Populationsdichten, an den Blattmasseverlusten beteiligt waren. Ursächlich schien die Austriebsstörung zu sein. Die überregionale Verbreitung der Schäden und die Symptomausprägung deuten auf eine abiotische Beeinträchtigung der Eichen hin. Die Annahme einer witterungsbedingten Schädigung ist nahe liegend, da im Rekordsommer“ 2003 mit über dem Durchschnitt liegenden Temperaturen, erheblichen Niederschlagsdefiziten und überdurchschnittlich hoher Sonnenscheindauer extreme Witterungsverhältnisse herrschten. Im Oktober 2003 kam es zu einem plötzlichen, gravierenden Temperatursturz. Überhöhte Temperaturen im Februar führten zu einer erneuten Belastung des Stoffwechsels der Eichen (HEYDECK & MÖLLER 2004).About the participation of defoliators in the oak decline symptoms in Brandenburg 2004. During spring 2004 a depressed shooting of the oaks were observed in many areas in the north east of Germany. Obvious is that the hot and dry summer 2003 caused these damages. The participation of leave feeding insects in 2004 and their current population densities are described. The necessity of insecticide applications in spring 2005 is discussed

    Optimal designs for enzyme inhibition kinetic models

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    In this paper we present a new method for determining optimal designs for enzyme inhibition kinetic models, which are used to model the influence of the concentration of a substrate and an inhibition on the velocity of a reaction. The approach uses a nonlinear transformation of the vector of predictors such that the model in the new coordinates is given by an incomplete response surface model. Although there exist no explicit solutions of the optimal design problem for incomplete response surface models so far, the corresponding design problem in the new coordinates is substantially more transparent, such that explicit or numerical solutions can be determined more easily. The designs for the original problem can finally be found by an inverse transformation of the optimal designs determined for the response surface model. We illustrate the method determining explicit solutions for the DD-optimal design and for the optimal design problem for estimating the individual coefficients in a non-competitive enzyme inhibition kinetic model

    The current outbreak of the European pine moth, Dendrolimus pini (Lep., Lasiocampidae) in the federal state of Brandenburg (Germany)

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    Das nordostdeutsche Tiefland ist historisch und aktuell ein Massenwechselgebiet für eine Reihe von Forstschadinsekten. Das gilt, bedingt durch die standörtlichen Verhältnisse und die gegenwärtige Dominanz der Kiefer, insbesondere für Brandenburg. Auf Grund des sehr hohen Risikos von irreversiblen Bestandesschäden durch nadelfressende Schmetterlinge und Blattwespen existieren flächige, dem aktuellen Gefährdungsstatus angepasste, standardisierte Überwachungsverfahren als Voraussetzung für die Prognose und Kontrolle.Since 2003 rising population densities of the European pine moth, Dendrolimus pini, have required an expensive monitoring in Brandenburg. Besides culmination and retrogradation of nun moth outbreak the forest areas where insecticide applications against pine moth caterpillars were necessary increased until now. In some extreme damaged areas the pine moth eggs showed a mortality rate of approximately 100 % caused by the parasitic wasp Telenomus laeviusculus. During the hot and dry summer in 2006 the regeneration potential of pines after total needle loss went down to 0 %

    Utbildningssubventioner - En uppsats om utbildningens vikt för ekonomisk tillväxt i utvecklingsländer

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    Den här uppsatsen undersöker de positiva och negativa effekter en subventionering av utbildning framkallar i en ekonomi. En investering i humankapitalet är en viktig del av produktionen och påverkar därmed inkomstnivåerna i positiv riktning. Samtidigt ger subventioneringen upphov till kostnader som kan påverka produktionen negativt och förorsaka låga initiala inkomster, lägre konsumtion och lägre sparande i realkapitalet, vilket skulle kunna medföra andra negativa konsekvenser för ekonomin. Frågeställningen är: – Hur påverkas ett utvecklingslands ekonomiska tillväxt på lång sikt av att subventionera utbildningssektorn? För att besvara frågeställningen utvecklas Lucas-modellen så att den ekonomisk-politiska åtgärden, som subventionering av utbildning är, synliggörs i funktionen för humankapitalet och realkapitalet. Finansieringen av subventioneringen av utbildning begränsas av en budgetrestriktion, som illustrerar vilka inkomstkällor som finns och hur mycket och hur stor andel som tilldelas humankapitalinvesteringen. Det genomförs en verklighetssimulering baserad på statistik för de utvecklingsländer som Världsbanken benämner som low income countries och low middle income countries. Simuleringarna utgår ifrån situationer som synliggör effekterna av att subventionera utbildningssektorn med olika typer av finansieringsmedel på BNP per capita nivån och tillväxttakten, humankapitalet samt realkapitalet. I varje situation simuleras fem olika strategier under övervägande om vilken skattesats som ska implementeras, för att man ska kunna se konsekvenserna av att variera mängden subventionering till utbildningssektorn. Resultaten visar att det är rationellt att subventionera utbildningssektorn för att uppnå högre tillväxt och att det är rationellt att höja skattesatsen istället för att finansiera en humankapitalinvestering med lånade medel. Dock bör ett antal institutionella problem avhjälpas innan en sådan investering kan äga rum och bli så effektiv som möjlig

    Perceived teacher unfairness and student motivation in math and German. An application of the generalized internal/external frame of reference model

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    The Generalized Internal/External Frame of Reference Model offers a framework according to which the perception of teacher characteristics might impact on students\u27 motivation within and between subjects. In the present study, relations between perceived teacher unfairness and student motivation in math and German were examined. In a sample of N = 1685 German secondary school students, perceived teacher unfairness was found to be negatively related with student self-concept, interest, and importance of doing well on the task within the subjects of math and German, while being positively related with the three aspects of student motivation between subjects. Mediation analyses revealed partial mediation through academic self-concept within, and complete mediation between subjects. The results imply that students\u27 motivation in one subject is not only related to perceived teacher characteristics in the corresponding subject, but also to the experiences that these students make with teachers in another subject. (DIPF/Orig.

    A role for the centrosome in regulating the rate of neuronal efferocytosis by microglia in vivo

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    During brain development, many newborn neurons undergo apoptosis and are engulfed by microglia, the tissue-resident phagocytes of the brain, in a process known as efferocytosis. A hallmark of microglia is their highly branched morphology characterized by the presence of numerous dynamic extensions that these cells use for scanning the brain parenchyma and engulfing unwanted material. The mechanisms driving branch formation and apoptotic cell engulfment in microglia are unclear. By taking a live-imaging approach in zebrafish, we show that while microglia generate multiple microtubule-based branches, they only successfully engulf one apoptotic neuron at a time. Further investigation into the mechanism underlying this sequential engulfment revealed that targeted migration of the centrosome into one branch is predictive of phagosome formation and polarized vesicular trafficking. Moreover, experimentally doubling centrosomal numbers in microglia increases the rate of engulfment and even allows microglia to remove two neurons simultaneously, providing direct supporting evidence for a model where centrosomal migration is a rate-limiting step in branch-mediated efferocytosis. Conversely, light-mediated depolymerization of microtubules causes microglia to lose their typical branched morphology and switch to an alternative mode of engulfment, characterized by directed migration towards target neurons, revealing unexpected plasticity in their phagocytic ability. Finally, building on work focusing on the establishment of the immunological synapse, we identified a conserved signalling pathway underlying centrosomal movement in engulfing microglia

    Die Krise in der Krise: existenzielle Bedrohung und gesellschaftliche Rezession im Königreich Preußen zu Beginn des 18. Jahrhunderts

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    Existenzielle Bedrohung meint hier das zeitgleiche Auftreten von Pestepidemien und Naturkatastrophen mit ihren Folgen. Die Arbeit setzt sich die Rekonstruktion von sozialer Kommunikation und sozialem Handeln am Beispiel der aufgetretenen Seuchen und Hungerkatastrophe zu Beginn des 18. Jahrhunderts im Herzogtum Preußen zum Ziel. Dabei verlangt die Kombination der Untersuchung von Kommunikationsprozessen und der Ereignisgeschichte unter dem Aspekt sozialgeschichtlicher Forschung eine fächerübergreifende Betrachtungsweise

    Разработка технологического процесса изготовления штока 2М138И.01.06.030 СБ

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    Раздел "Объект и методы исследования" содержит служебное назначение изделия, расчет годовой программы выпуска изделия. Раздел "Расчеты и аналитика" содержит выбор баз, разработку маршрута технологического процесса, выбор оборудования и средств технологического оснащения, расчёт припусков на обработку. В разделе "Результаты проведённого исследования" приведено описание конструкции и расчёт приспособления. Раздел "Социальная ответственность" посвящён вопросам безопасной работы на участке и пожарной безопасности. В разделе "Финансовый менеджмент, ресурсоэффективность и ресурсосбережение" рассчитана себестоимость изготовления детали.The section "Object and methods of research" contains the service purpose of the product, the calculation of the annual production program of the product. The section "Calculations and Analytics" contains the selection of bases, development of the route of the process. In the Section "Results of the research contains" the description of design and calculation of the adaptation. The section "Social responsibility" is devoted to the issues of safe work on the site and fire safety. In the section "Financial management, resource efficiency and resource saving" calculated the cost of manufacturing parts

    Coherent Charge Oscillations in a Bilayer Graphene Double Quantum Dot

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    The coherent dynamics of a quantum mechanical two-level system passing through an anti-crossing of two energy levels can give rise to Landau-Zener-St\"uckelberg-Majorana (LZSM) interference. LZSM interference spectroscopy has proven to be a fruitful tool to investigate charge noise and charge decoherence in semiconductor quantum dots (QDs). Recently, bilayer graphene has developed as a promising platform to host highly tunable QDs potentially useful for hosting spin and valley qubits. So far, in this system no coherent oscillations have been observed and little is known about charge noise in this material. Here, we report coherent charge oscillations and T2T_2^* charge decoherence times in a bilayer graphene double QD. The charge decoherence times are measured independently using LZSM interference and photon assisted tunneling. Both techniques yield T2T_2^* average values in the range of 400 to 500~ps. The observation of charge coherence allows to study the origin and spectral distribution of charge noise in future experiments.Comment: Article: 9 pages, 5 figures; Supplementary Information: 11 pages, 9 figure

    From Screening to Therapy: Anti-HCV Screening and Linkage to Care in a Network of General Practitioners and a Private Gastroenterology Practice

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    (1) Background: Low rates of hepatitis C virus (HCV) diagnosis and sub-optimal linkage to care constitute barriers toward eliminating the infection. In 2012/2013, we showed that HCV screening in primary care detects unknown cases. However, hepatitis C patients may not receive further diagnostics and therapy because they drop out during the referral pathway to secondary care. Thus, we used an existing network of primary care physicians and a practice of gastroenterology to investigate the pathway from screening to therapy. (2) Methods: HCV screening was prospectively included in a routine check-up of primary care physicians who cooperated regularly with a private gastroenterology practice. Anti-HCV-positive patients were referred for further specialized diagnostics and treatment if indicated. (3) Results: Seventeen primary care practices screened 1875 patients. Twelve individuals were anti-HCV-positive (0.6%), six of them reported previous antiviral HCV therapy, and one untreated patient was HCV-RNA-positive (0.05% of the population). None of the 12 anti-HCV-positive cases showed up at the private gastroenterology practice. Further clinical details of the pathway from screening to therapy could not be analyzed. (4) Conclusions: The linkage between primary and secondary care appears to be problematic in the HCV setting even among cooperating partners, but robust conclusions require larger datasets
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