Effects of two types of fatigue on the VO(2) slow component.

The aim of the study was to test the hypothesis of the involvement of type II fibres in the V.O (2) slow component phenomenon by using two prior fatiguing protocols on the knee extensor muscles. Nine subjects performed three constant-load cycling exercises at a work rate corresponding to 80 % of their V.O (2) max: (i) preceded by a 20-min fatiguing protocol using electromyostimulation (EMS), (ii) preceded by a 20-min fatiguing protocol using voluntary contractions (VOL), and (iii) without fatiguing protocol (NFP). Voluntary and evoked neuromuscular properties of the knee extensor muscles were tested before (PRE) and after (POST) the two fatiguing protocols. Results show a significant reduction in voluntary force after both fatiguing protocols (-19.9 % and -11.8 %, in EMS and VOL, respectively p<0.01). After EMS, this decrease was greater than after VOL (p<0.05) and was combined with a slackening of muscle contractile properties which was absent after VOL (p<0.05). Regarding the effects on oxygen uptake kinetics, the appearance of the slow component was delayed after EMS and its amplitude was lower than those obtained in VOL and NFP conditions (0.48+/-0.07 vs. 0.75+/-0.09 and 0.69+/-0.08 L . min (-1), respectively; p<0.05). It can thus be concluded that exercises dedicated to preferentially fatiguing type II fibres may alter V.O (2) kinetics.

An iterative Multiscale Finite-Volume algorithm converging to the exact solution

The multiscale finite volume (MsFV) method has been developed to efficiently solve large heterogeneous problems (elliptic or parabolic); it is usually employed for pressure equations and delivers conservative flux fields to be used in transport problems. The method essentially relies on the hypothesis that the (fine-scale) problem can be reasonably described by a set of local solutions coupled by a conservative global (coarse-scale) problem. In most cases, the boundary conditions assigned for the local problems are satisfactory and the approximate conservative fluxes provided by the method are accurate. In numerically challenging cases, however, a more accurate localization is required to obtain a good approximation of the fine-scale solution. In this paper we develop a procedure to iteratively improve the boundary conditions of the local problems. The algorithm relies on the data structure of the MsFV method and employs a Krylov-subspace projection method to obtain an unconditionally stable scheme and accelerate convergence. Two variants are considered: in the first, only the MsFV operator is used; in the second, the MsFV operator is combined in a two-step method with an operator derived from the problem solved to construct the conservative flux field. The resulting iterative MsFV algorithms allow arbitrary reduction of the solution error without compromising the construction of a conservative flux field, which is guaranteed at any iteration. Since it converges to the exact solution, the method can be regarded as a linear solver. In this context, the schemes proposed here can be viewed as preconditioned versions of the Generalized Minimal Residual method (GMRES), with a very peculiar characteristic that the residual on the coarse grid is zero at any iteration (thus conservative fluxes can be obtained).

Structures de gestion des rivalités d'usage du paysage : une analyse comparée de trois cas alpins

Résumé Objectifs : Le but de ce travail est, dans un premier temps, de mettre en évidence les mécanismes qui gouvernent les rivalités d'usage concernant la ressource paysage, afin, dans un deuxième temps, de comprendre comment se résolvent ces différends. Il part du postulat central que l'existence de rivalités d'usage non apaisées nuit à la durabilité de la ressource. Trois types d'acteurs gravitant autour de la ressource paysage doivent être distingués -Les observateurs du paysage sont ceux qui utilisent directement les services fournis par la ressource (p. ex. les touristes « écologiques », les randonneurs, les amoureux de la nature ; dans les conflits, ils peuvent être représentés par les organisations de protection du paysage) ; -Les fournisseurs du paysage servent d'intermédiaires entre le paysage et les observa¬teurs ; ils utilisent le paysage pour attirer des clients ; ils monnayent l'accès au paysage (billet de transport, hôtels, restaurant panoramique) ; ils vendent des représentations du paysage ; -Les utilisateurs des ressources « primaires » (sol, eau, forêt...) ne se préoccupent pas de paysage : ils entretiennent une configuration particulière de ressources primaires qui fait naître chez l'observateur le sentiment qu'il contemple un paysage. Ces catégories analytiques ne sont pas hermétiques, car un même acteur peut se trouver dans plusieurs catégories à la fois. Cadre d'analyse : Sur la base de la typologie des acteurs présentée, il est possible de mettre en évidence six types de rivalités théoriques, chacune opposant entre eux des observateurs, fournisseurs et utilisateurs de ressources primaires. Dans une situation de rivalité, les différents acteurs mobilisent les droits qu'ils ont à disposition pour défendre leurs intérêts. Le cadre d'analyse des régimes institutionnels de ressources naturelles (RIRN) est utilisé afin de mettre en évi¬dence ces droits. Il permet de faire la différence entre le système régulatif de la ressource, qui fait référence aux phénomènes d'appropriation (à défaut de propriété, car le paysage n'entre pas facilement dans les canons définis par le code civil), et les politiques publiques, qui ré¬glementent ces phénomènes d'appropriation. Le cadre des RIRN a la prétention de tisser un lien entre l'économie institutionnelle des ressources naturelles, préoccupée avant tout par la question des droits sur les ressources, et une approche plus politologique, dont les politi¬ques publiques constituent l'objet d'étude. Résultats : Dans le contexte de trois études de cas (le val Baltschieder, la région d'Aletsch et le parc naturel régional de Chartreuse), les conflits paysagers ont été mis en évidence. Les acteurs en présence ont été identifiés, de même que les droits dont ils disposent pour protéger leurs intérêts. Ce travail a démontré que les rivalités entre observateurs (p. ex. surdensité de visi¬teurs), ainsi que celles entre observateurs et utilisateurs de ressources primaires ne trouvent pas de solution sans l'intervention d'une structure de gestion paysagère particulière. Cette dernière peut prendre différentes formes qui doivent toutefois respecter un certain nombre de critères développés dans le travail. Dans le contexte des études de cas, différents modèles d'organisation susceptibles de jouer ce rôle ont été mis en évidence. De telles organisations collectives constituent une des clés pour une gestion durable de la ressource paysage.

New electrocardiographic criteria for discriminating between Brugada types 2 and 3 patterns and incomplete right bundle branch block.

OBJECTIVES: The aim of this study was to evaluate new electrocardiographic (ECG) criteria for discriminating between incomplete right bundle branch block (RBBB) and the Brugada types 2 and 3 ECG patterns. BACKGROUND: Brugada syndrome can manifest as either type 2 or type 3 pattern. The latter should be distinguished from incomplete RBBB, present in 3% of the population. METHODS: Thirty-eight patients with either type 2 or type 3 Brugada pattern that were referred for an antiarrhythmic drug challenge (AAD) were included. Before AAD, 2 angles were measured from ECG leads V(1) and/or V(2) showing incomplete RBBB: 1) α, the angle between a vertical line and the downslope of the r'-wave, and 2) β, the angle between the upslope of the S-wave and the downslope of the r'-wave. Baseline angle values, alone or combined with QRS duration, were compared between patients with negative and positive results on AAD. Receiver-operating characteristic curves were constructed to identify optimal discriminative cutoff values. RESULTS: The mean β angle was significantly smaller in the 14 patients with negative results on AAD compared to the 24 patients with positive results on AAD (36 ± 20° vs. 62 ± 20°, p < 0.01). Its optimal cutoff value was 58°, which yielded a positive predictive value of 73% and a negative predictive value of 87% for conversion to type 1 pattern on AAD; α was slightly less sensitive and specific compared with β. When the angles were combined with QRS duration, it tended to improve discrimination. CONCLUSIONS: In patients with suspected Brugada syndrome, simple ECG criteria can enable discrimination between incomplete RBBB and types 2 and 3 Brugada patterns.

Splenic hypereosinophilia in anaphylaxis-related death: different assessments depending on different types of allergens?

The aim of this study was to evaluate splenic eosinophil and mast cell accumulation using pagoda red stain in a series of anaphylaxis-related deaths that underwent medico-legal investigations. Our goal was to assess whether fatal reactions to insect stings, intramuscularly administered antibiotics and intravenously injected contrast media are responsible for specific patterns of eosinophil and mast cell accumulation. Two study groups were prospectively formed, an anaphylaxis-related death group and a control group. Autopsy, histology (haematoxylin-eosin stain, pagoda red stain and immunohistochemistry using anti-tryptase antibodies), toxicology and postmortem biochemistry (beta-tryptase, total IgE and specific IgE) were performed in all cases. All tested parameters (spleen weight, beta-tryptase and total IgE levels as well as eosinophil, mast cell and degranulated mast cell numbers in the spleen) were significantly higher in the anaphylaxis-related death group. No statistically significant differences were observed among the various groups (intramuscular antibiotic injection, intravenous contrast medium administration and stinging insects) in any combination, suggesting that mast cell and eosinophil accumulation in the spleen during anaphylaxis does not have any specific pattern related to the triggering allergen. Despite a lower sensitivity than immunohistochemical staining in discriminating eosinophil and mast cells, pagoda red stain allowed these cells to be identified and could therefore be proposed as a low-cost, first-line diagnostic procedure in those situations where immunohistochemistry is not systematically performed or cannot be carried out.

Several neuronal and axonal types form long intrinsic connections in the cat primary auditory cortical field (AI).

Intrinsic connections in the cat primary auditory field (AI) as revealed by injections of Phaseolus vulgaris leucoagglutinin (PHA-L) or biocytin, had an anisotropic and patchy distribution. Neurons, labelled retrogradely with PHA-L were concentrated along a dorsoventral stripe through the injection site and rostral to it; the spread of rostrally located neurons was greater after injections into regions of low rather than high characteristic frequencies. The intensity of retrograde labelling varied from weak and granular to very strong and Golgi-like. Out of 313 Golgi like retrogradely labelled neurons 79.6% were pyramidal, 17.2% multipolar, 2.6% bipolar, and 0.6% bitufted; 13.4% were putatively inhibitory, i.e. aspiny or sparsely spiny multipolar, or bitufted. Individual anterogradely labelled intrinsic axons were reconstructed for distances of 2 to 7 mm. Five main types were distinguished on the basis of the branching pattern and the location of synaptic specialisations. Type 1 axons travelled horizontally within layers II to VI and sent collaterals at regular intervals; boutons were only present in the terminal arborizations of these collaterals. Type 2 axons also travelled horizontally within layers II to VI and had rather short and thin collateral branches; boutons or spine-like protrusions occurred in most parts of the axon. Type 3 axons travelled obliquely through the cortex and formed a single terminal arborization, the only site where boutons were found. Type 4 axons travelled for some distance in layer I; they formed a heterogeneous group as to their collaterals and synaptic specializations. Type 5 axons travelled at the interface between layer VI and the white matter; boutons en passant, spine-like protrusions, and thin short branches with boutons en passant were frequent all along their trajectory. Thus, only some axonal types sustain the patchy pattern of intrinsic connectivity, whereas others are involved in a more diffuse connectivity.

Testing the use of two types of nest box by the common dormouse Muscardinus avellanarius

British mammalogists have used two different systems for surveying the common dormouse Muscardinus avellanarius: a modified bird nest box with the entrance facing the tree trunk, and a smaller, cheaper model called a "nest tube". However, only few data comparing different nest box systems are currently available. To determine which system is more efficient, we compared the use of the large (GB-type) and small nest boxes (DE-type, a commercial wooden mouse trap without a door) in three Swiss forest. The presence of Muscardinus, potential competitors, and any evidence of occupation were examined in 60 pairs of nest boxes based on 2,280 nest box checks conducted over 5 years. Mean annual occupation and cumulative numbers of Muscardinus present were both significantly higher for the DE than for the GB boxes (64.6% versus 32.1%, and 149 versus 67 dormice, respectively). In contrast, the annual occupation by competitors including Glis glis, Apodemus spp. and hole-nesting birds was significantly higher in the GB than in the DE boxes in all forest (19-68% versus 0-16%, depending on the species and forest). These results suggest that smaller nest boxes are preferred by the common dormouse and are rarely occupied by competitors. These boxes hence appear to be preferable for studying Muscardinus populations.

The Four Different Types of Internal Hernia Occurring After Laparascopic Roux-en-Y Gastric Bypass Performed for Morbid Obesity: Are There Any Multidetector Computed Tomography (MDCT) Features Permitting Their Distinction?

BACKGROUND: Four different types of internal hernias (IH) are known to occur after laparoscopic Roux-en-Y gastric bypass (LRYGBP) performed for morbid obesity. We evaluate multidetector row helical computed tomography (MDCT) features for their differentiation. METHODS: From a prospectively collected database including 349 patients with LRYGBP, 34 acutely symptomatic patients (28 women, mean age 32.6), operated on for IH immediately after undergoing MDCT, were selected. Surgery confirmed 4 (11.6%) patients with transmesocolic, 10 (29.4%) with Petersen's, 15 (44.2%) with mesojejunal, and 5 (14.8%) with jejunojejunal IH. In consensus, 2 radiologists analyzed 13 MDCT features to distinguish the four types of IH. Statistical significance was calculated (p < 0.05, Fisher's exact test, chi-square test). RESULTS: MDCT features of small bowel obstruction (SBO) (n = 25, 73.5%), volvulus (n = 22, 64.7%), or a cluster of small bowel loops (SBL) (n = 27, 79.4%) were inconsistently present and overlapped between the four IH. The following features allowed for IH differentiation: left upper quadrant clustered small bowel loops (p < 0.0001) and a mesocolic hernial orifice (p = 0.0003) suggested transmesocolic IH. SBL abutting onto the left abdominal wall (p = 0.0021) and left abdominal shift of the superior mesenteric vessels (SMV) (p = 0.0045) suggested Petersen's hernia. The SMV predominantly shifted towards the right anterior abdominal wall in mesojejunal hernia (p = 0.0033). Location of the hernial orifice near the distal anastomosis (p = 0.0431) and jejunojejunal suture widening (p = 0.0005) indicated jejunojejunal hernia. CONCLUSIONS: None of the four IH seems associated with a higher risk of SBO. Certain MDCT features, such as the position of clustered SBL and hernial orifice, help distinguish between the four IH and may permit straightforward surgery.