Group heterogeneity and social validation of everyday knowledge: the mediating role of perceived group participation

Studies presented in this article show that participants attribute greater validity to opinions supported by heterogeneous groups than by homogeneous ones, that this effect occurs whether participants anticipate group belonging or not and that the relationship between heterogeneity and the attribution of validity to opinions is mediated by the perception of participation within heterogeneous groups. More specifically, an experimental scenario was tested in a pilot study (N = 299): group heterogeneity was manipulated and perceived group participation as well as perceived validity of group opinions was measured. Results show the expected effect of heterogeneity on the validation of opinions and also a mediating effect of perceived participation. The main study (N = 336) shows that the effect of heterogeneity occurs not only when participants are mere observers of groups but also when they anticipate group belonging. Furthermore, this study shows that whereas the effect of group heterogeneity was mediated by perceived participation, the effect of group belonging on perceived validity of group opinions was mediated by trust

Aortic valve replacement with the freestyle stentless bioprosthesis with respect to spacial orientation of patient coronary ostia

AbstractObjective: This study evaluates our results for safety and efficacy of aortic valve replacement using the Freestyle bioprosthesis (Medtronic, Inc, Minneapolis, Minn) with a new modified subcoronary implantation technique. This technique takes into account the spacial orientation of the stentless bioprosthesis in the aortic root with respect to the patient’s coronary ostia rather than the native commissures. Methods: Fifty-two consecutive patients with predominant aortic valve stenosis underwent aortic valve replacement with a Freestyle bioprosthesis by means of the described modified subcoronary technique over a 15-month period. Fifty of them were followed up by means of echocardiography at discharge, 6 months, and 1 year. There were 19 men and 31 women, with a mean age of 76 ± 7 years (range, 58-87 years). Valve size ranged from 21 to 27 mm. Results: Patients with bicuspid aortic valves had a significantly larger angle between both coronary ostia than patients with tricuspid aortic valves (P = .0001). The peak and mean systolic gradients decreased significantly during the first postoperative year for each valve size (P ≤ .001), and the effective valve areas increased significantly during this time interval for each valve size (P ≤ .01). Only 13 patients had aortic insufficiency at discharge, which was trivial in 9 and mild in 4 patients. The prevalence of trivial aortic insufficiency decreased during the first postoperative year, and that of mild aortic insufficiency remained unchanged. The sinotubular junction diameter was significantly greater than that of the aortic anulus for each valve size before operation (P < .001). The sinotubular junction diameter decreased significantly after aortic valve replacement and remained unchanged during the first postoperative year for each valve size (P < .001). Conclusions: Aortic valve replacement with the Freestyle bioprosthesis using the modified subcoronary technique, which takes into account the spacial orientation of the patient’s coronary ostia, has hemodynamic results similar to those of other series with different subcoronary implantation techniques. This technique is reproducible, safe at the coronary ostial level, and effective in accommodating variability in angles between human coronary ostia, ranging from 130° to 170°. Moreover, the great preoperative discrepancies between aortic anulus and sinotubular junction diameters are corrected immediately after operation. (J Thorac Cardiovasc Surg 2000;119:1185-93

Long-term outcome after surgical intervention and interventional procedures for the management of Takayasu’s arteritis in children

ObjectiveThere is little information available on the results of reconstructive arterial surgery for Takayasu’s arteritis in children. This study evaluates midterm to long-term outcome after surgical, as well as interventional, procedures.MethodsFrom 1984 through 2004, 10 children (5 boys and 5 girls; age, 12.7 ± 2.6 years) with Takayasu’s arteritis were referred to our center. Baseline cardiovascular assessment included contrast angiography (n = 4), magnetic resonance imaging–angiography (n = 3), and combined contrast angiography plus magnetic resonance imaging–angiography (n = 3). Two patients had disease confined to the thoracic aorta, 4 had disease confined to the abdominal aorta, and 4 had combined thoracoabdominal aortic disease. Steno-occlusive lesions were predominant in 92% of cases. Seven patients were maintained on steroid therapy throughout the follow-up period. Eight children underwent complex surgical procedures, 1 patient had balloon dilatation of the renal and mesenteric arteries, and 1 patient had combined vascular surgery with percutaneous transluminal angioplasty. Overall, 24 grafts (polytetrafluoroethylene, Dacron grafts, and cryopreserved homografts) were implanted in various locations.ResultsThere were no perioperative deaths. Arterial hypertension regressed in all patients, and cardiac function normalized in all 4 patients with dilative cardiomyopathy. Over a 20-year period, 1 patient presented with sudden death and 2 showed nonfatal disease progression, one of whom required surgical reintervention. The occlusion rate was higher in Dacron grafts.ConclusionsOur study shows that despite the extent and severity of vascular lesions, children with Takayasu’s arteritis could benefit from reconstructive surgery, with low mortality, morbidity, and satisfactory long-term results

Mesure de la double désintégration bêta avec émission de deux neutrinos du Mo100 vers l'état excité 0+(1) dans l'expérience NEMO3

Le détecteur NEMO3 a été conçu pour l'étude de la double désintégration bêta et particulièrement pour la recherche de la double désintégration bêta sans émission de neutrino. La sensibilité attendue pour la double désintégration bêta sans émission de neutrino est, en terme de la demi-vie de l'ordre de 10^25 ans, en terme de " masse effective " du neutrino, cela correspond à une sensibilité (0,3 - 0,1) eV. Ce mode de désintégration représente aujourd'hui le test de la nature "Majorana " du neutrino le plus prometteur. Le détecteur a été construit au Laboratoire Souterrain de Modane en France par la collaboration internationale (France, Russie, République Tchèque, Etats-Unis, Royaume-Uni, Finlande et Japon). La prise de données a commencé en mai 2002 et continue actuellement. La masse de Mo100 dans le détecteur (7 kg) permet une mise en évidence de la double désintégration bêta avec émission de deux neutrinos du Mo100 vers l'état excité 0+(1). Les simulations Monte-Carlo de l'effet et de tous les types de bruit de fond ont été effectuées pour définir un ensemble des critères de sélection appropriés. D'autre part des runs avec des sources de Tl208 et du Bi214 ainsi que des simulations Monte-Carlo de ces données ont montré que le seul bruit de fond significatif dans le canal " deux électrons et plusieurs gammas " vient du radon qui a pénétré à l'intérieur de la chambre à fils de NEMO3. Les données expérimentales acquises de mai 2002 à mai 2003 ont été analysées pour déterminer le signal dû à la double désintégration bêta avec émission de deux neutrinos du Mo100 vers l'état excité 0+(1) et le niveau de bruit de fond correspondant. Le résultat est donné sous la forme d'un intervalle de valeurs de la demi-vie au niveau de 95% de confiance. Cela correspond à une mise en évidence du processus au niveau de confiance de 4 écarts standards.The NEMO3 detector was designed for the study of double beta decay and in particular for the search for neutrinoless double beta decay process. The intended sensitivity in the term of a half-life limit for the neutrinoless double beta decay is of the order of 10^25 years, which corresponds to the effective neutrino mass on the level of (O.3 -0.1) eV. The neutrinoless process is today the most promising test of the "Majorana" nature of the neutrino. The detector was constructed in the Modane Underground Laboratory (LSM) in France by an international collaboration including France, Russia, the Czech Republic, the USA, the UK, Finland, and Japan. The experiment has been taking data since May 2002. The quantity of Mo100 in the detector (7 kg) allows an efficient measurement of the two-neutrino double beta decay of Mo100 to the excited 0+(1) state. Monte-Carlo simulations of the effect and of all the relative sources of background have been done in order to define a set of appropriate selection criteria. Both Monte-Carlo simulations and special runs with sources of Tl208 and Bi214 showed that the only significant background in the analysis channel "two electrons and N photons" comes from radon that penetrated inside the wire chamber of NEMO3. The experimental data acquired from May 2002 to May 2003 have been analysed in order to determine the signal from the two-neutrino double beta decay of Mo100 to the excited 0+(1) state and the corresponding background level. The physical result, which was obtained at the level of four standard deviations, is given in the form of an interval of half-life values at 95% confidence level.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Choice of graft material at primary CABG influences cardiac death and reintervention rates

To evaluate long-term survival and need for reintervention (redo CABG or percutaneous coronary artery transluminal angioplasty, PTCA) as a result of graft materials employed at the primary coronary artery bypass grafting (CABG)