On multi-species diffusion with size exclusion

We revisit a classical continuum model for the diffusion of multiple species with size-exclusion constraint, which leads to a degenerate nonlinear cross-diffusion system. The purpose of this article is twofold: first, it aims at a systematic study of the question of existence of weak solutions and their long-time asymptotic behaviour. Second, it provides a weak-strong stability estimate for a wide range of coefficients, which had been missing so far. In order to achieve the results mentioned above, we exploit the formal gradient-flow structure of the model with respect to a logarithmic entropy, which leads to best estimates in the full-interaction case, where all cross-diffusion coefficients are non-zero. Those are crucial to obtain the minimal Sobolev regularity needed for a weak-strong stability result. For meaningful cases when some of the coefficients vanish, we provide a novel existence result based on approximation by the full-interaction case

On multi-species diffusion with size exclusion

We revisit a classical continuum model for the diffusion of multiple species with size-exclusion constraint, which leads to a degenerate nonlinear cross-diffusion system. The purpose of this article is twofold: first, it aims at a systematic study of the question of existence of weak solutions and their long-time asymptotic behaviour. Second, it provides a weak-strong stability estimate for a wide range of coefficients, which had been missing so far. In order to achieve the results mentioned above, we exploit the formal gradient-flow structure of the model with respect to a logarithmic entropy, which leads to best estimates in the full-interaction case, where all cross-diffusion coefficients are non-zero. Those are crucial to obtain the minimal Sobolev regularity needed for a weak-strong stability result. For meaningful cases when some of the coefficients vanish, we provide a novel existence result based on approximation by the full-interaction case

Understanding behaviour in problem structuring methods interventions with activity theory

This article argues that OR interventions, particularly problem structuring methods (PSM), are complex events that cannot be understood by conventional methods alone. In this paper an alternative approach is introduced, where the units of analysis are the activity systems constituted by and constitutive of PSM interventions. The paper outlines the main theoretical and methodological concerns that need to be appreciated in studying PSM interventions. The paper then explores activity theory as an approach to study them. A case study describing the use of this approach is provided

Richer, wiser and in better health? The socioeconomic gradient in hypertension prevalence, unawareness and control in South Africa

The socioeconomic gradient in chronic conditions is clear in the poorest and wealthiest of countries, but extant evidence on this relationship in low- and middle-income countries is inconclusive. We use data gathered between 2008 and 2012 from a nationally representative sample of over 10,000 South African adults, and objective health measures to analyse the differential effects of education, income and other factors on the prevalence of hypertension, individuals' awareness and control of hypertensive status. Prevalence of hypertension is high at 38% among women and 34% among men. 59% of hypertensive individuals are unaware of their status. We find prevalence and unawareness of hypertension are a public health concern across all income groups in South Africa. Higher income is however associated with effective control amongst men. Completing secondary education is associated with 7 mmHg lower blood pressure only in a small sub-group of women but is associated with 22 percentage point higher likelihood of effective hypertension control amongst women. We conclude that poorer and less educated individuals are particularly at high risk of cardiovascular disease in South Africa

"Wir sind niemand und wir haben nichts." - Jenseits des Todes HM3, Heiner Müller Antikenmaterial

JENSEITS DES TODES HM3, ein Theaterversuch mit Heiner Müllers Antikenmaterial (33 Texte), fand 2006 – 2007 in Wien statt und wurde nicht, wie im künstlerischen Bereich sonst üblich, medial-digital aufgezeichnet. Die Beteiligten entschieden sich für das Schreiben als einzige Dokumentationsform des Arbeitsprozesses, im Sinne einer Vielzahl von Stimmen und Perspektiven, die in der Gesamtheit die Autorschaft des Einzelnen gegenstandslos macht. Offen blieb die Frage: was geschieht nach Beendigung der Arbeit mit dem Gesamt-Schrift-Material? Wie geht man damit um? Die vorliegende Arbeit ist ein Vorschlag dazu: Skizzen zu einem Theaterversuch. Wissend, dass die Beschreibung von JDT HM3 keine herkömmliche wissenschaftliche Untersuchung, Analyse oder Interpretation werden konnte, dass das Protokollmaterial in seiner Lückenhaftigkeit nach einer anderen Umgangsweise verlangte und dass es mir um keine Festschreibung oder lineare Dokumentation der Praxis ging, habe ich mich für ein Schreiben „zwischen den Fronten“ entschieden. Die Folge ist, dass im Text zwar theatergeschichtliche und -wissenschaftliche Elemente und Problemstellungen auftauchen, wie z.B. Bertolt Brechts Lehrstückansatz oder Hans-Thies Lehmanns These von der Unterbrechung des Politischen im Theater. Diese führen aber in Bezug auf JDT HM3 zu Fragen, auf die es keine endgültigen Antworten geben kann (die Erkenntnisse sind immer vorläufige, endgültig ist nur ihre Verschiedenheit). Theatertheorie kollidiert mit Theaterpraxis. Die Montage der Textmaterialien impliziert Sprünge, Absenzen, Verbindungen und Brüche. Es ist der Versuch einer Fortschreibung, mit Blick in die Zukunft

A modified fluorimetric host cell reactivation assay to determine the repair capacity of primary keratinocytes, melanocytes and fibroblasts

<p>Abstract</p> <p>Background</p> <p>The Host Cell Reactivation Assay (HCRA) is widely used to identify circumstances and substances affecting the repair capacity of cells, however, it is restricted by the transfection procedure used and the sensitivity of the detection method. Primary skin cells are particularly difficult to transfect, and therefore sensitive methods are needed to detect any variations due to the cell-type or inter-individual differences or changes induced by diverse substances.</p> <p>A sensitive and repeatable method to detect the repair capacity of skin cells would be useful in two different aspects: On the one hand, to identify substances influencing the repair capacity in a positive manner (these substances could be promising ingredients for cosmetic products) and on the other hand, to exclude the negative effects of substances on the repair capacity (this could serve as one step further towards replacing or at least reducing animal testing).</p> <p>Results</p> <p>In this paper, we present a rapid and sensitive assay to determine the repair capacity of primary keratinocytes, melanocytes and fibroblasts based on two wave-length Green Fluorescent Protein (GFP) and DsRed reporter technology in order to test different substances and their potential to influence the DNA repair capacity. For the detection of plasmid restoration, we used FACS technology, which, in comparison to luminometer technology, is highly sensitive and allows single cell based analysis.</p> <p>The usefulness of this assay and studying the repair capacity is demonstrated by the evidence that DNA repair is repressed by Cyclosporin A in fibroblasts.</p> <p>Conclusions</p> <p>The methodology described in this paper determines the DNA repair capacity in different types of human skin cells. The described transfection protocol is suitable for the transfection of melanocytes, keratinocytes and fibroblasts, reaching efficacies suitable for the detection of the restored plasmids by FACS technology. Therefore the repair capacity of different cell types can be compared with each other. The described assay is also highly flexible, and the activity of other repair mechanisms can be determined using modifications of this method.</p