Recollements of Module Categories

We establish a correspondence between recollements of abelian categories up to equivalence and certain TTF-triples. For a module category we show, moreover, a correspondence with idempotent ideals, recovering a theorem of Jans. Furthermore, we show that a recollement whose terms are module categories is equivalent to one induced by an idempotent element, thus answering a question by Kuhn.Comment: Comments are welcom

Categorical Tinkertoys for N=2 Gauge Theories

In view of classification of the quiver 4d N=2 supersymmetric gauge theories, we discuss the characterization of the quivers with superpotential (Q,W) associated to a N=2 QFT which, in some corner of its parameter space, looks like a gauge theory with gauge group G. The basic idea is that the Abelian category rep(Q,W) of (finite-dimensional) representations of the Jacobian algebra $\mathbb{C} Q/(\partial W)$ should enjoy what we call the Ringel property of type G; in particular, rep(Q,W) should contain a universal `generic' subcategory, which depends only on the gauge group G, capturing the universality of the gauge sector. There is a family of 'light' subcategories $\mathscr{L}_\lambda\subset rep(Q,W)$, indexed by points $\lambda\in N$, where $N$ is a projective variety whose irreducible components are copies of $\mathbb{P}^1$ in one--to--one correspondence with the simple factors of G. In particular, for a Gaiotto theory there is one such family of subcategories, $\mathscr{L}_{\lambda\in N}$, for each maximal degeneration of the corresponding surface $\Sigma$, and the index variety $N$ may be identified with the degenerate Gaiotto surface itself: generic light subcategories correspond to cylinders, while closed-point subcategories to `fixtures' (spheres with three punctures of various kinds) and higher-order generalizations. The rules for `gluing' categories are more general that the geometric gluing of surfaces, allowing for a few additional exceptional N=2 theories which are not of the Gaiotto class.Comment: 142 pages, 8 figures, 5 table

Expansion and Harvesting of hMSC-TERT

The expansion of human mesenchymal stem cells as suspension culture by means of spinner flasks and microcarriers, compared to the cultivation in tissue culture flasks, offers the advantage of reducing the requirements of large incubator capacities as well as reducing the handling effort during cultivation and harvesting. Nonporous microcarriers are preferable when the cells need to be kept in viable condition for further applications like tissue engineering or cell therapy. In this study, the qualification of Biosilon, Cytodex 1, Cytodex 3, RapidCell and P102-L for expansion of hMSC-TERT with an associated harvesting process using either trypsin, accutase, collagenase or a trypsin-accutase mixture was investigated. A subsequent adipogenic differentiation of harvested hMSC-TERT was performed in order to observe possible negative effects on their (adipogenic) differentiation potential as a result of the cultivation and harvesting method. The cultivated cells showed an average growth rate of 0.52 d-1. The cells cultivated on Biosilon, RapidCell and P102-L were harvested succesfully achieving high cell yield and vitalities near 100%. This was not the case for cells on Cytodex 1 and Cytodex 3. The trypsin-accutase mix was most effective. After spinner expansion and harvesting the cells were successfully differentiated to adipocytes

Sounds of Silence : The Reflexivity, Self-decentralization, and Transformation Dimensions of Silence at Work

This article explores silence as a phenomenon and practice in the workplace through a Buddhist-enacted lens where silence is intentionally encouraged. It brings forward a reconsideration of the roles of silence in organizations by proposing emancipatory dimensions of silence—reflexivity, self-decentralization, and transformation. Based on 54 interviews with employees and managers in a Vietnamese telecommunications organization, we discuss the dynamic nature of silence, and the possible coexistence of the constructive and the oppressive aspects of silence in a workplace spirituality context. Instead of studying silence as one-dimensional, we call for an integrated view and argue that studying silence requires consideration of the multiplicity of its interconnected dimensions. By considering silence as a relational and emerging processes constructed around its vagueness and uncertainties, our study reveals the many possible ways silence is organized and organizes and sheds light on silence as a marker of the complexities and paradoxes of organizational life

Ethylene flame : effects of pressure on soot properties

International audienceYe

Mesures de la taille et de la concentration de la suie dans une flamme laminaire prémélangée

Une étude expérimentale est réalisée sur une série de flammes laminaires d'un prémélange propène-air. La flamme de forme conique est stabilisée sur un brûleur à surface poreuse et entourée par une flamme de méthane pour assurer son isolement. La technique d'incandescence induite par laser (IIL) calibrée par celle de l'extinction du laser, est utilisée pour déterminer la distribution spatiale (2D) de la fraction volumique de la suie pour trois valeurs de la pression, P = 1, 3 et 5 bar à diverses richesses. Pour les flammes à pression atmosphérique, l'investigation est étendue à la détermination de la taille des particules de suie par la mesure du taux de décroissance temporelle du signal IIL(t). Pour ce dernier, la température locale des gaz est mesurée par la technique de diffusion Raman anti-Stokes cohérente (DRASC) décalée indispensable pour les flammes avec suie. Les résultats obtenus sont discutés et constituent une base de données pour valider d'éventuels résultats de modèles théoriques de simulation de la formation de la suie dans une flamme monodimensionnelle