L'énergie éolienne en Auvergne : questions sur une ressource en plein essor

International audienceSouvent présentée comme une énergie renouvelable dont le développement serait indispensable pour un avenir plus respectueux de l’environnement, l’énergie éolienne, qui commence tout juste à se développer en Auvergne, nous pose des questions. Comment les projets auvergnats s’inscrivent-ils dans les dynamiques nationales ? Jusqu’où l’éolien peut-il se développer dans la région, quel est son potentiel ? Quels sont les rôles et les stratégies des différents acteurs concernés ?Quelles sont les limites d’une telle dynamique, et les résistances qu’elle rencontre

The Bocage Landscape in the ‘Bourbonnais’ (Allier Department, France): between Heritage and Modern Dynamics

The Allier department has an incredible range of landscapes among which the bocage is the most representative. The bocage is an enclosed field with scattered households. Some areas are also totally free of hedge. We did not want to compare the openfield and the bocage but we tried to prove that there was a different type of bocage. So we studied two opposed sectors situated in the East and in the West of this department. The use of aerial shootings and their processing in a G.I.S. (Geographical Information System) allowed us to map the differences between the two areas in the last 50 years. This objective description obtained from actual and past data helped us analyse the change factors in the whole bocage of the Allier department

La couverture forestière du Haut Livradois : marque de déclin ou opportunité de développement ?

Deuxième prix du concours de posters scientifiques du festivalInternational audienceSous l’Ancien Régime, le Haut Livradois était l’une des montagnes les plus densément peuplées de France, offrant des paysages largement ouverts et dominés par l’activité agricole. Aujourd’hui, 68 % de la surface du Haut Livradois est boisée, et le taux de boisement dépasse même 80 % dans certaines communes. Ainsi, l’occupation de l’espace a profondément évolué au cours du vingtième siècle. Au fil des décennies, le couvert forestier s’est étendu de manière anarchique dans le Haut Livradois. Le paysage actuel est façonné par des boisements incontrôlés. L’économie autour de la filière bois reste peu développée. Des actions politiques tentent d’améliorer la situation

Les recherches contemporaines en géographie rurale : territoires, ressources et pratiques du terrain

International audienceCe texte est une synthèse des réflexions partagées par les doctorants présents lors d'une journée organisée à Montpellier, le 26 mars 2009, par la commission française de géographie rurale. Il pose la question de la spécificité des recherches géographiques sur les espaces ruraux à partir de trois entrées épistémologiques et méthodologiques : le territoire, les ressources et la pratique du terrain. Les regards croisés des huit contributeurs, enrichis de leurs propres expériences de recherche et d'une journée commune de terrain, montrent que les problèmes de délimitation des territoires d'étude, de caractérisation des ressources locales et de méthodologie d'investigation préoccupent les jeunes chercheurs géographes

Challenges in assessing exposure and vulnerability to natural hazards in large cities: the case study of Arequipa near the Misti volcano, south Peru

Assessing risk of potential natural catastrophes in cities remains challenging, in particular as we need to elaborate quantitative criteria for exposure and vulnerability. Statistical and probabilistic methods have been applied to Arequipa, one of the most vulnerable Latin America cities. The second largest city of Peru is highly exposed to natural hazards: earthquakes, eruptions from the historically active El Misti volcano, rain-triggered flash floods and mass flows together with landslides from the Río Chili canyon walls. First, we propose a long-term probabilistic multi-hazard assessment for the Misti composite cone located 17 km from Arequipa. Second, we examine criteria for delineating areas prone to mass flow hazards and characterizing multiple sources of vulnerability forthe city. Third, a statistical methodology to better estimate damage probability for buildings is proposed

DNA Methylation Causes Predominant Maternal Controls of Plant Embryo Growth

The parental conflict hypothesis predicts that the mother inhibits embryo growth counteracting growth enhancement by the father. In plants the DNA methyltransferase MET1 is a central regulator of parentally imprinted genes that affect seed growth. However the relation between the role of MET1 in imprinting and its control of seed size has remained unclear. Here we combine cytological, genetic and statistical analyses to study the effect of MET1 on seed growth. We show that the loss of MET1 during male gametogenesis causes a reduction of seed size, presumably linked to silencing of the paternal allele of growth enhancers in the endosperm, which nurtures the embryo. However, we find no evidence for a similar role of MET1 during female gametogenesis. Rather, the reduction of MET1 dosage in the maternal somatic tissues causes seed size increase. MET1 inhibits seed growth by restricting cell division and elongation in the maternal integuments that surround the seed. Our data demonstrate new controls of seed growth linked to the mode of reproduction typical of flowering plants. We conclude that the regulation of embryo growth by MET1 results from a combination of predominant maternal controls, and that DNA methylation maintained by MET1 does not orchestrate a parental conflict

Repression of FLOWERING LOCUS C and FLOWERING LOCUS T by the Arabidopsis Polycomb Repressive Complex 2 Components

Polycomb group (PcG) proteins are evolutionarily conserved in animals and plants, and play critical roles in the regulation of developmental gene expression. Here we show that the Arabidopsis Polycomb repressive complex 2 (PRC2) subunits CURLY LEAF (CLF), EMBRYONIC FLOWER 2 (EMF2) and FERTILIZATION INDEPENDENT ENDOSPERM (FIE) repress the expression of FLOWERING LOCUS C (FLC), a central repressor of the floral transition in Arabidopsis and FLC relatives. In addition, CLF directly interacts with and mediates the deposition of repressive histone H3 lysine 27 trimethylation (H3K27me3) into FLC and FLC relatives, which suppresses active histone H3 lysine 4 trimethylation (H3K4me3) in these loci. Furthermore, we show that during vegetative development CLF and FIE strongly repress the expression of FLOWERING LOCUS T (FT), a key flowering-time integrator, and that CLF also directly interacts with and mediates the deposition of H3K27me3 into FT chromatin. Our results suggest that PRC2-like complexes containing CLF, EMF2 and FIE, directly interact with and deposit into FT, FLC and FLC relatives repressive trimethyl H3K27 leading to the suppression of active H3K4me3 in these loci, and thus repress the expression of these flowering genes. Given the central roles of FLC and FT in flowering-time regulation in Arabidopsis, these findings suggest that the CLF-containing PRC2-like complexes play a significant role in control of flowering in Arabidopsis

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)