Confiance et gouvernement des entreprises: le rôle de la confiance dans la relation capital-investisseurs et dirigeants et son influence sur la performance

Ce papier de recherche étudie l'influence du niveau de confiance interpersonnelle existant entre capital investisseurs et dirigeants d'entreprise sur trois types de variables : les processus d'interaction qui caractérisent leur relation, les rôles tenus par les capital investisseurs vis à vis des dirigeants dans la phase post-investissement, et, par l'intermédiaire de ces processus et rôles, sur la performance financière de l'investissement dans les entreprises concernées. Notre hypothèse centrale est que la confiance favorise les processus d'interaction et les rôles des capital investisseurs qui ont une influence positive sur la performance financière des entreprises, et donc sur celle de l'investissement qui a été opéré dans ces entreprises. Nous utilisons un cadre théorique éclectique (théorie de l'agence d'une part, théories de la confiance et de la coopération d'autre part) pour construire un modèle qui fait l'objet d'un test empirique au moyen d'une enquête par questionnaire sur un échantillon d'opérations de LBOs réalisés en France. Nos résultats montrent que le niveau de confiance interpersonnelle influe sur l'ensemble des processus d'interaction, ainsi que sur un nombre limité de rôles des capital investisseurs. Par contre ils ne mettent en évidence aucune relation directe entre confiance et performance financière de l'investissement.capital investissement; capital risque; LBO; gouvernement d'entreprise; conseil d'administration; dirigeants, confiance; coopération

A non-parametric probabilistic model for soil-structure interaction

International audienceThe paper investigates the effect of soil-structure interaction on the dynamic response of structures. A non-parametric probabilistic formulation for the modelling of an uncertain soil impedance is used to account for the usual lack of information on soil properties. Such a probabilistic model introduces the physical coupling stemming from the soil heterogeneity around the foundation. Considering this effect, even a symmetrical building displays a torsional motion when submitted to earthquake loading. The study focuses on a multi-story building modeled by using equivalent Timoshenko beam models which have different mass distributions. The probability density functions of the maximal internal forces and moments in a given building are estimated by Monte Carlo simulations. Some results on the stochastic modal analysis of the structure are also given

Playing with models. How to use agent-based models with stakeholders for understanding social-ecological systems

While science has long been regarded as the sole driver for development, it is nowadays acknowledged that inclusion of stakeholders and different scientific perspectives is required to improve our understanding on socio-ecological systems (SESs). To integrate various perceptions and knowledge, there is a growing interest for Agent-Based Models (ABMs) as participatory tools for understanding SESs and their likely evolutions. Because they are centered on individuals, ABMs enable the user of a simulation to visualize his system in a tangible way. Consequently, he can project himself in the simulated word by assuming the role of an agent. Because he can also observe the system at the global level, he can better understand the consequences of decisions and actions. Some experiments using ABMs combine autonomous processes with agents' actions decided by the actors. Such “hybrid agent” simulations enable the stakeholders to interact with the model by modifying the behavior of the agents and the way they use the resources. Therefore, we can collectively explore scenarios to better understand how a desired situation may be reached. This may feed back into the collective design of the model. This talk will include two parts: (1) a brief overview of the ABMs and the pros and cons to use them with stakeholders as a participatory modeling approach and (2) an example of experiment with local communities in an Amazon floodplain in Brazil coping with global changes. A hands-on demonstration of this experiment will be available to the workshop participants to play with the model to better understand the advantages and the limits of such methodology. Beyond the technical and organizational considerations for designing and using such tools, we address the issue of power plays and of how to integrate in the process all the involved stakeholders while strengthening the capacities of the most vulnerable. (Texte integral

Recombinant human erythropoietin therapy after allogeneic hematopoietic cell transplantation with a nonmyeloablative conditioning regimen: low donor chimerism predicts for poor response.

peer reviewedPURPOSE: After allogeneic hematopoietic stem cell transplantation with nonmyeloablative conditioning (NMHCT), many patients experience prolonged anemia and require red blood cell (RBC) transfusions. We enrolled 60 consecutive patients undergoing NMHCT in a phase II trial to determine the optimal utilization of recombinant human erythropoietin (rHuEPO) therapy in this setting. PATIENTS AND METHODS: The first 14 NMHCT recipients did not receive rHuEPO (control group). Nineteen patients were scheduled to start rHuEPO on day 0 (EPO group 2) and 27 patients on day 28 after the transplant (EPO group 1). RHuEPO was administered subcutaneously once weekly at a dose of 500 U/kg/wk with the aim of achieving hemoglobin (Hb) levels of 13 g/dL. The 3 groups were well balanced for major characteristics. RESULTS: During the first month (p < 0.0001) as well as days 30 to 100 (p < 0.0001) and days 100 to 180 (p < 0.0001), Hb values were higher in patients receiving rHuEPO compared to those not receiving it. However, transfusion requirements were significantly decreased only in the first month in EPO group 2 (p = 0.0169). T-cell chimerism above 60% on day 42 was the best predictor of Hb response (p < 0.0001) or Hb correction (p = 0.0217), but myeloid chimerism above 90% also predicted for Hb response (p = 0.0069). Hb response was also decreased in patients receiving CD8-depleted grafts and increased in the few patients not receiving TBI, but only in univariate analysis. CONCLUSIONS: Anemia after NMHCT is sensitive to rHuEPO therapy, but less so than after conventional allogeneic HCT. RHuEPO decreases transfusion requirements only in the first 30 days posttransplant. T-cell chimerism below 60% on day 42 impaired Hb response, suggesting possible inhibition of donor erythropoiesis by residual recipient lymphocytes. A prospective randomized trial should be performed with rHuEPO starting on the day of transplantation to assess its clinical benefit in terms of transfusion requirements and quality of life

Erythropoietin therapy after allogeneic hematopoietic cell transplantation : a prospective randomized trial

We conducted a prospective randomized trial to assess hemoglobin (Hb) response to recombinant human erythropoietin (rhEPO) therapy after hematopoietic cell transplantation (HCT). Patients (n=131) were randomized (1:1) between no treatment (control arm) or erythropoietin (Neorecormon®) at 500 U/kg/week (EPO arm). Patients were also stratified in 3 cohorts: patients undergoing myeloablative HCT with rhEPO to start on day 28, patients given nonmyeloablative HCT (NMHCT) with rhEPO to start on day 28, and patients also given NMHCT but with rhEPO to start on day 0. The proportion of complete correctors (i.e. achieving Hb ≥ 13 g/dL) before day 126 post-transplant (primary endpoint) was 8.1% in the control arm (median not reached) and 63.1% in the EPO arm (median time 90 days) (p<0.001). Hb levels were higher and transfusions requirements decreased (p<0.001) in the EPO arm, but not during the first month in the nonmyeloablative cohort starting rhEPO on day 0. There was no difference in rates of thrombo-embolic events or other complications between the 2 arms. This is the first randomized trial to demonstrate that rhEPO therapy hastens erythroid recovery and decreases transfusion requirements when started one month after allogeneic HCT. There was no benefit to start rhEPO earlier after NMHCT

Nevirapine versus Efavirenz for patients co-infected with HIV and Tuberculosis: A Randomised Non-Inferiority Trial

BACKGROUND: In countries with a high incidence of HIV and tuberculosis co-infection, nevirapine and efavirenz are widely used as antiretroviral therapy but both interact with antituberculosis drugs. We aimed to compare efficacy and safety of a nevirapine-based antiretroviral therapy (started at full dose) with an efavirenz-based regimen in co-infected patients. METHODS: We did a multicentre, open-label, randomised, non-inferiority trial at three health centres in Maputo, Mozambique. We enrolled adults (≥18 years) with tuberculosis and previously untreated HIV infection (CD4 cell counts <250 cells per μL) and alanine aminotransferase and total bilirubin concentrations of less than five times the upper limit of normal. 4-6 weeks after the start of tuberculosis treatment, we randomly allocated patients (1:1) with central randomisation, block sizes of two to six, and stratified by site and CD4 cell count to nevirapine (200 mg twice daily) or efavirenz (600 mg once daily), plus lamivudine and stavudine. The primary endpoint was virological suppression at 48 weeks (HIV-1 RNA <50 copies per mL) in all patients who received at least one dose of study drug (intention-to-treat population); death and loss to follow-up were recorded as treatment failure. The non-inferiority margin for the difference of efficacy was 10%. We assessed efficacy in intention-to-treat and per-protocol populations and safety in all patients who received study drug. This study is registered with ClinicalTrials.gov, number NCT00495326. FINDINGS: Between October, 2007, and March, 2010, we enrolled 285 patients into each group. 242 (85%) patients in the nevirapine group and 233 (82%) patients in the efavirenz group completed follow-up. In the intention-to-treat population, 184 patients (64·6%, 95% CI 58·7-70·1) allocated nevirapine achieved virological suppression at week 48, as did 199 patients (69·8%, 64·1-75·1) allocated efavirenz (one-sided 95% CI of the difference of efficacy 11·7%). In the per-protocol population, 170 (70·0%, 63·8-75·7) of 243 patients allocated nevirapine achieved virological suppression at week 48, as did 194 (78·9%, 73·2-83·8) of 246 patients allocated efavirenz (one-sided 95% CI 15·4%). The median CD4 cell count at randomisation was 89 cells per μL. 15 patients substituted nevirapine with efavirenz and six patients substituted efavirenz with nevirapine. 20 patients allocated nevirapine (7%) had grade 3-4 increase of alanine aminotransferase compared with 17 patients allocated efavirenz (6%). Three patients had severe rash after receipt of nevirapine (1%) but no patients did after receipt of efavirenz. 18 patients in the nevirapine group died, as did 17 patients in the efavirenz group. INTERPRETATION: Although non-inferiority of the nevirapine-regimen was not shown, nevirapine at full dose could be a safe, acceptable alternative for patients unable to tolerate efavirenz. FUNDING: French Research Agency for HIV/AIDS and hepatitis (ANRS)