MM*STAT: Eine interaktive Einführung in die Welt der Statistik

MM*STAT ist ein flexibel einsetzbares Tool für Einführungskurse in Statistik im Grundstudium. Folgende konzeptionelle Überlegungen waren dabei von besonderer Bedeutung: Erstens muss die Lehrveranstaltung "Statistik" für Studenten jeder Fachrichtung ein breites Spektrum konkreter Anwendungsmöglichkeiten statistischer Techniken vermitteln. Eine rein theoretische Darlegung wird von den Studenten üblicherweise als "langweilig" empfunden. Weil die statistische Analyse in der Praxis nie ohne Computeranwendung erfolgt, sollte zweitens die Statistik-Lehrveranstaltung auch den Erwerb entsprechender Fertigkeiten beinhalten. Drittens ist Statistik auf Grund immer komplexerer Datenstrukturen, statistischer Methoden und Modelle immer "komplizierter" geworden. Dies erfordert ein zunehmend differenziertes Spezialwissen, das natürlich auch Bestandteil der Lehre sein muss. Viertens: Ungeachtet dieser hohen Anforderungen ist die verfügbare Zeit in der Lehre, insbesondere bei den Einführungskursen, über die Jahre konstant geblieben oder wurde sogar reduziert

Effekte einzelbaumweise eingemischter einheimischer Eichen in Wäldern der Gemeinen Kiefer (Pinus sylvestris L.) auf Standorten geringer Trophie und Wasserversorgung im Süden Brandenburgs

Das Forschungsvorhaben hat das Ziel den Einfluss einzelbaumweise eingemischter einheimischer Eichen in Wäldern der Gemeinen Kiefer (Pinus sylvestris L.) zu untersuchen. Die Untersuchungsflächen befinden sich im Nordosten Deutschlands (Brandenburg). Im Untersuchungsgebiet Jerischke hat die Kiefer ein Alter von 78 Jahren und die Eiche ein Alter von 205 Jahren. Im Untersuchungsgebiet Weidmannsruh befindet sich die Kiefer im Alter 70 und die Eiche im Alter 108. In Abhängigkeit von der Entfernung zur Eiche werden folgende Effekte der Eiche nach Intensität und Qualität untersucht: - Effekte auf Mikroklima und Strahlung, - Effekte auf Humusmorphologie und bodenchemische Parameter und - Effekte auf Bodenvegetation und epigäische Fauna. Grundsätzlich sind die positiven Effekte der Eiche auf 10 bis 15 m vom Eichenstamm in den Kiefernbestand hinein begrenzt

Shirking or mismatch? Coach-team separation in German professional soccer

Some authors suggest that firing a coach reflects a principal-agent problem between team managers and coaches. Another explanation emphasizes the matching problem between teams and coaches. This paper provides empirical evidence for the latter: Using German soccer league data, we analyze the determinants of coach dismissals in terms of the impact of a team's performance on the probability to be fired. It is shown that the probability for a coach dismissal increases over time

Exploring Patterns of Dynamic Size Changes of Lesions after Hepatic Microwave Ablation in an In Vivo Porcine Model

Microwave ablation (MWA) is a type of minimally invasive cancer therapy that uses heat to induce necrosis in solid tumours. Inter- and post-ablational size changes can influence the accuracy of control imaging, posing a risk of incomplete ablation. The present study aims to explore post-ablation 3D size dynamics in vivo using computed tomography (CT). Ten MWA datasets obtained in nine healthy pigs were used. Lesions were subdivided along the z-axis with an additional planar subdivision into eight subsections. The volume of the subsections was analysed over different time points, subsequently colour-coded and three-dimensionally visualized. A locally weighted polynomial regression model (LOESS) was applied to describe overall size changes, and Student's t-tests were used to assess statistical significance of size changes. The 3D analysis showed heterogeneous volume changes with multiple small changes at the lesion margins over all time points. The changes were pronounced at the upper and lower lesion edges and characterized by initially eccentric, opposite swelling, followed by shrinkage. In the middle parts of the lesion, we observed less dimensional variations over the different time points. LOESS revealed a hyperbolic pattern for the volumetric changes with an initially significant volume increase of 11.6% (111.6% of the original volume) over the first 32 minutes, followed by a continuous decrease to 96% of the original volume (p < 0.05)

Imaging the Thermalization of Hot Carriers After Thermionic Emission Over a Polytype Barrier

The thermalization of non-equilibrium charge carriers is at the heart of thermoelectric energy conversion. In nanoscale systems, the equilibration length can be on the order of the system size, leading to a situation where thermoelectric effects need to be considered as spatially distributed, rather than localized at junctions. The energy exchange between charge carriers and phonons is of fundamental scientific and technological interest, but their assessment poses significant experimental challenges. We addressed these challenges by imaging the temperature change induced by Peltier effects in crystal phase engineered InAs nanowire (NW) devices. Using high-resolution scanning thermal microscopy (SThM), we have studied current-carrying InAs NWs, which feature a barrier segment of wurtzite (WZ) of varying length in a NW of otherwise zincblende (ZB) crystal phase. The energy barrier acts as a filter for electron transport around the Fermi energy, giving rise to a thermoelectric effect. We find that thermalization through electron-phonon heat exchange extends over the entire device. We analyze the temperature profile along a nanowire by comparing it to spatially dependent heat diffusion and electron thermalization models. We are able to extract the governing properties of the system, including the electron thermalization length of $223 \pm 9$\,nm, Peltier coefficient and Seebeck coefficient introduced by the barrier of $39 \pm 7$\,mV and $89 \pm 21$\,$\mu$V/K, respectively, and a thermal conductivity along the wire axis of $8.9 \pm 0.5$\,W/m/K. Finally, we compare two ways to extract the elusive thermal boundary conductance between NW and underlying substrate

Fundamental questions on the economics of climate adaptation: Outlines of a new research programme

In view of the failure of international negotiations on climate protection and the improbability of a trend reversal in the climate changes that have already occurred, the option of climate change adaptation is becoming more and more important in climate change policy. A large number of countries have already initiated a process of adaptation by drafting strategies or catalogues of measures. Hence there is an urgent need to support this process at the scientific level. The discipline of economics has a key role to play in this context, especially with regard to the design, evaluation and selection of adaptation measures and instruments. The still relatively young field of research into the economics of adaptation is growing at a considerable pace and already exhibits a wide range of methodological approaches and research questions. Against this background, the present report aims to undertake a systematic structuring and synthesis of the individual research studies in order to provide political actors with an overview of the scientific recommendations and findings they must consider when making decisions. Another aim of the report is to identify open research questions and, based on this, to outline key pointers for the future direction of the research into the economics of climate adaptation

Molybdenum-isotope signals and cerium anomalies in Palaeoproterozoic manganese ore survive high-grade metamorphism

Abstract Molybdenum (Mo) and its isotopes have been used to retrieve palaeoenvironmental information on the ocean–atmosphere system through geological time. Their application has so far been restricted to rocks least affected by severe metamorphism and deformation, which may erase or alter palaeoenvironmental signals. Environmental Mo-isotope signatures can be retrieved if the more manganese (Mn)-enriched rocks are isotopically depleted and the maximum range of δ98Mo values is close to the ~2.7‰ Mo-isotope fractionation known from Mo sorption onto Mn oxides at low temperature. Here, we show that the Morro da Mina Mn-ore deposit in Minas Gerais, Brazil, contains Mn-silicate–carbonate ore and associated graphitic schist that likely preserve δ98Mo of Palaeoproterozoic seawater, despite a metamorphic overprint of at least 600 °C. The extent of Mo-isotope fractionation between the Mn-silicate–carbonate ore and the graphitic schist is similar to modern Mn-oxide precipitates and seawater. Differences in δ98Mo signals are broadly reflected in cerium (Ce) anomalies, which suggest an oxic–anoxic-stratified Palaeoproterozoic ocean