Trees with Given Stability Number and Minimum Number of Stable Sets

We study the structure of trees minimizing their number of stable sets for given order $n$ and stability number $\alpha$. Our main result is that the edges of a non-trivial extremal tree can be partitioned into $n-\alpha$ stars, each of size $\lceil \frac{n-1}{n-\alpha} \rceil$ or $\lfloor \frac{n-1}{n-\alpha}\rfloor$, so that every vertex is included in at most two distinct stars, and the centers of these stars form a stable set of the tree.Comment: v2: Referees' comments incorporate

Acute pulmonary oedema on the Ruwenzori mountain range.

A 40 year old man had an episode of severe pulmonary oedema at 4000-5000 m during the ascent of the Margherita peak (5109 m) of Mount Stanley on the Ruwenzori. He had taken acetazolamide and high dose dexamethasone to treat symptoms of acute mountain sickness. Six years before he had been studied by right heart catheterisation as a healthy volunteer during hypoxic breathing at sea level. His pulmonary vascular reactivity had been within the normal range for 32 healthy subjects. This man had high altitude pulmonary oedema despite currently recommended treatments for acute mountain sickness and normal pulmonary vascular reactivity to hypoxia at sea level

Measuring pulmonary arterial compliance: mission impossible? Insights from a novel in vivo continuous-flow based experimental model

Arterial compliance (C) is related to the elasticity, size, and geometrical distribution of arteries. Compliance is a determinant of the load that impedes ventricular ejection. Measuring compliance is difficult, particularly in the pulmonary circulation in which resistive and compliant vessels overlap. Comparing different methods for quantification of compliance to a method that involves a continuous flow might help to identify the optimal method. Pulmonary arterial compliance was computed in six pigs based on the stroke volume to pulse pressure ratio, diastolic decay exponential fitting, area method, and the pulse pressure method (PPM). Compliance measurements were compared to those obtained under continuous flow conditions through a right ventricular bypass (Heartware Inc. Miami Lakes, FL, USA). Compliance was computed for various flows using diastolic decay exponential fitting after an abrupt interruption of the pump. Under the continuous flow conditions, resistance (R) was a decreasing function of the flow, and the fitting to P = e-t/RC yielded a pulmonary time constant (RC) of 2.06 s (± 0.48). Compliance was an increasing function of flow. Steady flow inter-method comparisons of compliance under pulsatile flow conditions showed large discrepancies and values (7.23 ± 4.47 mL/mmHg) which were lower than those obtained under continuous flow conditions (10.19 ± 1 0.31 mL/mmHg). Best agreement with steady flow measurements is obtained with the diastolic decay method. Resistance and compliance are both flow-dependent and are inversely related in the pulmonary circulation. The dynamic nature of the pulsatile flow may induce a non-uniformly distributed compliance, with an influence on the methods of measurement.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

FDC-B1, a new monoclonal antibody directed against bovine follicular dendrititic cells.

Follicular dendritic cells (FDCs) are unique immunological accessory cells located in the light and dark zones of the germinal centres in lymph follicles. Characterized by long branching processes forming a three-dimensional network, FDCs create particular microenvironments for germinal centre B and T cells and contribute to the maturation of B cells into memory cells. An involvement of the FDCs is suspected in various disorders affecting lymphoid tissues, malignant lymphoma or in some viral diseases. Moreover, in prion diseases, FDCs seem to be the major sites of extraneuronal cellular prion protein expression and the principal sites of the infectious agent accumulation in lymph organs. Because no antibody commercially available was specific to bovine FDCs, a new monoclonal antibody directed against bovine FDCs (FDC-B1) has been produced and characterized in our laboratory. The antigen detected by FDC-B1 is expressed on FDC surfaces in ruminant (bovine, ovine and caprine) lymphoid organs. This protein seems to be a membrane glycoprotein of more or less 28 kDa whose sequence will be soon determined. Moreover, FDC-B1 can be used in various applications: immunofluorescence, immunoperoxidase, immunogold labellings and western blotting. FDCs are potential targets for therapy or prophylaxis in natural TSEs, such as bovine spongiform encephalopathies and scrapie. Thus, it appears of great interest to identify bovine and ovine FDCs in routine lymphoid tissues sections. An other application of this antibody to immunofluorescence histochemistry techniques will enable the study of possible direct contacts between bovine FDCs and nerve endings and thus clarify prions neuroinvasion scheme in the case of BSE and scrapie

Développement d’un instrument pour l’évaluation des besoins de soutien dans les situations de handicap : Volet 1. Résumé

nrpages: 13status: publishe

De ontwikkeling van een instrument voor de evaluatie van de ondersteuningsbehoeften in handicapsituaties: Luik 1

status: publishe