The Weiss conjecture on admissibility of observation operators for contraction semigroups

We prove the conjecture of George Weiss for contraction semigroups on Hilbert spaces, giving a characterization of infinite-time admissible observation functionals for a contraction semigroup, namely that such a functional C is infinite-time admissible if and only if there is an M > 0 such that parallel to IC(sI - A)(-1)parallel to less than or equal to M/root Re s for all s in the open right half-plane. Here A denotes the infinitesimal generator of the semigroup. The result provides a simultaneous generalization of several celebrated results from the theory of Hardy spaces involving Carleson measures and Hankel operators

Social research goes internet: Online-Forschung auf dem Weg zum innovativen Instrumentarium der Politikanalyse

'Die Entwicklung neuer und innovativer Technologien ermöglicht die Weiterentwicklung methodologischer Forschung, dies trifft insbesondere auf die erweiterten Möglichkeiten für das sozialwissenschaftliche Methodeninstrumentarium durch die Informations- und Kommunikationstechnologien (IKT) zu. Im vorliegenden Beitrag soll zunächst eine Begriffsklärung vorgenommen werden, der ein allgemeiner Überblick über die quantitative Onlineforschung, ihre derzeit gebräuchlichsten Methoden sowie eine Diskussion der Grenzen der Onlineforschung folgt. Im dritten Teil des Textes soll auf die Chancen für qualitative Forschungsmethoden durch Neue Technologien hingewiesen und auf zwei Fallbeispiele eingegangen werden. Den Abschluss bildet ein Ausblick auf potenzielle Anwendungsmöglichkeiten der Ansätze der Onlineforschung in der politikwissenschaftlichen Forschung.' (Autorenreferat)'The emergence of new and innovative technologies contributes to the further development of research methodology. Especially the internet and other communication technologies have augmented the options for methodological tools in the social sciences. This article aims first to clarify the scope of online research, then offers an overview of quantitative online research, its currently used methods and a discussion of its limitations. The third part of this contribution deals with the chances of new technologies for qualitative online research. The last section consists of an outline of online methods in political science and indicates potential research areas.' (author's abstract

Social Research Goes Internet: Online- Forschung auf dem Weg zum innovativen Instrumentarium der Politikanalyse

Die Entwicklung neuer und innovativer Technologien ermöglicht die Weiterentwicklung methodologischer Forschung; dies trifft insbesondere auf die erweiterten Möglichkeiten für das sozialwissenschaftliche Methodeninstrumentarium durch die Informations- und Kommunikationstechnologien (IKT) zu.Im vorliegenden Beitrag soll zunächst eine Begriffsklärung vorgenommen werden, der ein allgemeiner Überblick über die quantitative Onlineforschung, ihre derzeit gebräuchlichsten Methoden sowie eine Diskussion der Grenzen der Onlineforschung folgt. Im dritten Teil des Textes soll auf die Chancen für qualitative Forschungsmethoden durch Neue Technologien hingewiesen und auf zwei Fallbeispiele eingegangen werden. Den Abschluss bildet ein Ausblick auf potenzielle Anwendungsmöglichkeiten der Ansätze der Onlineforschung in der politikwissenschaftlichen Forschung

9th Delta Conference of Teaching and Learning of Undergraduate Mathematics and Statistics 2013: Shining Through the Fog

With the diversity in the backgrounds of students currently entering universities, many students lack the preparedness to undertake studies that include quantitative content. At the same time, many of these students are required to enrol in an introductory statistics course at some stage during their undergraduate program of study. This, along with an associated prevalence of statistics anxiety, means that many students require additional assistance to progress and stay engaged. A variety of support mechanisms may need to be enacted to assist students to succeed. This paper introduces and discusses the development of StatsCasts: short, focused screencasts on topics students have struggled with in the past, for anywhere, anytime support in learning statistical concepts. An evaluation of the pilot stage of a larger research project is presented, to show how students at one of the three collaborating universities perceive these multi-media support resources, and to what level students access them. Initial findings indicate that most students found the StatsCasts beneficial to their learning and understanding of the relevant concepts

The Weiss conjecture and weak norms

In this note we show that for analytic semigroups the so-called Weiss condition of uniform boundedness of the operators Re(\lambda)^\einhalb C(\lambda+A)^{-1}, \qquad Re(\lambda)>0 on the complex right half plane and weak Lebesgue $L^{2,\infty}$--admissibility are equivalent. Moreover, we show that the weak Lebesgue norm is best possible in the sense that it is the endpoint for the 'Weiss conjecture' within the scale of Lorentz spaces $L^{p,q}$

Mechanisms controlling anaemia in Trypanosoma congolense infected mice.

Trypanosoma congolense are extracellular protozoan parasites of the blood stream of artiodactyls and are one of the main constraints on cattle production in Africa. In cattle, anaemia is the key feature of disease and persists after parasitaemia has declined to low or undetectable levels, but treatment to clear the parasites usually resolves the anaemia. The progress of anaemia after Trypanosoma congolense infection was followed in three mouse strains. Anaemia developed rapidly in all three strains until the peak of the first wave of parasitaemia. This was followed by a second phase, characterized by slower progress to severe anaemia in C57BL/6, by slow recovery in surviving A/J and a rapid recovery in BALB/c. There was no association between parasitaemia and severity of anaemia. Furthermore, functional T lymphocytes are not required for the induction of anaemia, since suppression of T cell activity with Cyclosporin A had neither an effect on the course of infection nor on anaemia. Expression of genes involved in erythropoiesis and iron metabolism was followed in spleen, liver and kidney tissues in the three strains of mice using microarrays. There was no evidence for a response to erythropoietin, consistent with anaemia of chronic disease, which is erythropoietin insensitive. However, the expression of transcription factors and genes involved in erythropoiesis and haemolysis did correlate with the expression of the inflammatory cytokines Il6 and Ifng. The innate immune response appears to be the major contributor to the inflammation associated with anaemia since suppression of T cells with CsA had no observable effect. Several transcription factors regulating haematopoiesis, Tal1, Gata1, Zfpm1 and Klf1 were expressed at consistently lower levels in C57BL/6 mice suggesting that these mice have a lower haematopoietic capacity and therefore less ability to recover from haemolysis induced anaemia after infection

Which variables are associated with blood glucose levels outside the target range in surgical critically ill patients? A retrospective observational study

<p>Abstract</p> <p>Background</p> <p>The aim of the present study is to determine the variables affecting blood glucose concentrations outside the target range of 80 and 150 mg/dl in critically ill surgical patients.</p> <p>Methods</p> <p>All critically ill surgical patients admitted to a university ICU, from 01/2007 to 12/2008, were surveyed daily using computer assistance with respect to minimal and maximal daily blood glucose concentrations, application of insulin and demographic/clinical variables. Multiple logistic regression for clustered data with backward elimination was performed to identify variables strongly associated with blood glucose concentrations < 80 mg/dl or ≥ 150 mg/dl in 804 patients with an ICU stay > 72 hours.</p> <p>Results</p> <p>Application of insulin (odds ratio (OR) 2.1, with corresponding 95% confidence interval (CI) 1.7; 2.6), noradrenaline (OR 1.4, 95% CI 1.2 - 1.8) or steroids (1.3, 1.003 - 1.7), and age (per year) (1.02, 1.01 - 1.03) were associated with an increased risk of blood glucose concentrations < 80 mg/dl. In analogy, application of insulin (OR 2.4, 95% CI 2.0 - 2.7), noradrenaline (1.4, 1.2 - 1.6) or steroids (1.4, 1.2 - 1.7), severe sepsis (1.2, 1.1 - 1.4), neurosurgery (OR 1.0) compared to abdominal, vascular and trauma surgery, and age (per year) (1.01, 1.01 - 1.02), were associated with an increased risk of blood glucose concentrations ≥ 150 mg/dl.</p> <p>Conclusions</p> <p>Critically ill surgical patients are at an increased risk for fluctuating blood glucose concentrations ranging < 80 mg/dl or ≥ 150 mg/dl in particular if they are of advanced age and require administration of insulin, noradrenaline, and/or steroids. Patients who underwent neurosurgery and/or presented with severe sepsis/shock are those in particular at risk for blood glucose concentrations ≥ 150 mg/dl.</p

Hierarchical super-structure identified by polarized light microscopy, electron microscopy and nanoindentation: implications for the limits of biological control over the growth mode of abalone sea shells

Background: Mollusc shells are commonly investigated using high-resolution imaging techniques based on cryo-fixation. Less detailed information is available regarding the light-optical properties. Sea shells of Haliotis pulcherina were embedded for polishing in defined orientations in order to investigate the interface between prismatic calcite and nacreous aragonite by standard materialographic methods. A polished thin section of the interface was prepared with a defined thickness of 60 μm for quantitative birefringence analysis using polarized light and LC-PolScope microscopy. Scanning electron microscopy images were obtained for comparison. In order to study structural-mechanical relationships, nanoindentation experiments were performed. Results: Incident light microscopy revealed a super-structure in semi-transparent regions of the polished cross-section under a defined angle. This super-structure is not visible in transmitted birefringence analysis due to the blurred polarization of small nacre platelets and numerous organic interfaces. The relative orientation and homogeneity of calcite prisms was directly identified, some of them with their optical axes exactly normal to the imaging plane. Co-oriented "prism colonies" were identified by polarized light analyses. The nacreous super-structure was also visualized by secondary electron imaging under defined angles. The domains of the super-structure were interpreted to consist of crystallographically aligned platelet stacks. Nanoindentation experiments showed that mechanical properties changed with the same periodicity as the domain size. Conclusions: In this study, we have demonstrated that insights into the growth mechanisms of nacre can be obtained by conventional light-optical methods. For example, we observed super-structures formed by co-oriented nacre platelets as previously identified using X-ray Photo-electron Emission Microscopy (X-PEEM) [Gilbert et al., Journal of the American Chemical Society 2008, 130:17519–17527]. Polarized optical microscopy revealed unprecedented super-structures in the calcitic shell part. This bears, in principle, the potential for in vivo studies, which might be useful for investigating the growth modes of nacre and other shell types

Hierarchical super-structure identified by polarized light microscopy, electron microscopy and nanoindentation: Implications for the limits of biological control over the growth mode of abalone sea shells

Mollusc shells are commonly investigated using high-resolution imaging techniques based on cryo-fixation. Less detailed information is available regarding the light-optical properties. Sea shells of Haliotis pulcherina were embedded for polishing in defined orientations in order to investigate the interface between prismatic calcite and nacreous aragonite by standard materialographic methods. A polished thin section of the interface was prepared with a defined thickness of 60 μm for quantitative birefringence analysis using polarized light and LC-PolScope microscopy. Scanning electron microscopy images were obtained for comparison. In order to study structural-mechanical relationships, nanoindentation experiments were performed.Incident light microscopy revealed a super-structure in semi-transparent regions of the polished cross-section under a defined angle. This super-structure is not visible in transmitted birefringence analysis due to the blurred polarization of small nacre platelets and numerous organic interfaces. The relative orientation and homogeneity of calcite prisms was directly identified, some of them with their optical axes exactly normal to the imaging plane. Co-oriented "prism colonies" were identified by polarized light analyses. The nacreous super-structure was also visualized by secondary electron imaging under defined angles. The domains of the super-structure were interpreted to consist of crystallographically aligned platelet stacks. Nanoindentation experiments showed that mechanical properties changed with the same periodicity as the domain size.In this study, we have demonstrated that insights into the growth mechanisms of nacre can be obtained by conventional light-optical methods. For example, we observed super-structures formed by co-oriented nacre platelets as previously identified using X-ray Photo-electron Emission Microscopy (X-PEEM) [Gilbert et al., Journal of the American Chemical Society 2008, 130:17519–17527]. Polarized optical microscopy revealed unprecedented super-structures in the calcitic shell part. This bears, in principle, the potential for in vivo studies, which might be useful for investigating the growth modes of nacre and other shell types

Preface and acknowledgements

This collection is the outcome of a Maastricht Research Based Learning Project (MARBLE) that took place at the Faculty of Arts and Social Sciences at Maastricht University in spring 2011. Under the guidance of Jens Lachmund (who is a lecturer at that faculty) a group of nine students worked on eight distinct case-studies on the culture and politics of product labelling