Implications of the 2019–2020 megafires for the biogeography and conservation of Australian vegetation

Australia's 2019–2020 'Black Summer' bushfires burnt more than 8 million hectares of vegetation across the south-east of the continent, an event unprecedented in the last 200 years. Here we report the impacts of these fires on vascular plant species and communities. Using a map of the fires generated from remotely sensed hotspot data we show that, across 11 Australian bioregions, 17 major native vegetation groups were severely burnt, and up to 67–83% of globally significant rainforests and eucalypt forests and woodlands. Based on geocoded species occurrence data we estimate that >50% of known populations or ranges of 816 native vascular plant species were burnt during the fires, including more than 100 species with geographic ranges more than 500 km across. Habitat and fire response data show that most affected species are resilient to fire. However, the massive biogeographic, demographic and taxonomic breadth of impacts of the 2019–2020 fires may leave some ecosystems, particularly relictual Gondwanan rainforests, susceptible to regeneration failure and landscape-scale decline

DataSheet_1_Deleterious effects of free fatty acids and hydrogen peroxide towards the dinoflagellate Gymnodinium catenatum.zip

Allelopathy refers to biochemical interactions among competing microalgae, it involves a donor species that produces metabolites which can cause inhibitory effects on susceptible species. This phenomenon can participate in the regulation of harmful algal blooms. The dinoflagellate Gymnodinium catenatum is negatively affected by allelopathic interactions with co-occurring microalgae species, like Chattonella marina var. marina, which has been suggested to produce reactive oxygen species (ROS) and free fatty acids (FFA) as nocive and allelopathic agents. This study explored the effect of hydrogen peroxide (H2O2) and the main fatty acids produced by C. marina. An analysis of fatty acids content of C. marina in exponential phase detected 16:0 (12.5 ± 0.01%), 18:4ω-3 (15.4 ± 0.36%) and 20:5ω-3 (35.4 ± 0.71%) as the most abundant. These fatty acids along with H2O2 were used in dose-response bioassays with cultures of G. catenatum in exponential phase. Results suggest that these substances affect cell morphology, including the loss of motility and signs of chlorosis, as well as the chain forming qualities of G. catenatum. Toxicity among these substances varied, suggesting that the polyunsaturated fatty acid 18:4ω-3 can potentially act as a more effective allelochemical (LD50 = 1.7 ± 0.19 mg L-1 at 24 h), followed by 20:5ω-3 (LD50 = 3.6 ± 0.17 mg L-1 at 24 h) and the saturated fatty acid 16:0 (LD50 = 6.2 ± 1.05 at 48 h). Our results suggest these substances can act, at least partially, as allelochemicals, with PUFA being the most effective metabolites. These results contribute in elucidating the potential role of ROS and FFA in allelopathy in marine phytoplankton communities.</p

Santé mentale et organisation du travail, Approche juridique et regards croisés

International audienc

Le bassin d’Arcachon entre attractivité et protection

Ce numéro thématique porte sur la tension entre attractivité et protection dans le bassin d’Arcachon. Les littoraux en général, et le bassin d’Arcachon en particulier, sont confrontés au paradoxe d’une attractivité qu’il s’agit à la fois de soutenir (en diversifier les ressorts) mais également de contenir (en contrôler les effets induits). L’attractivité du bassin dépend en partie de la capacité à préserver les ressources paysagères et environnementales à forte valeur patrimoniale. L’attractivité peut aussi devenir une contrainte : elle impose un partage de l’espace, des ressources territoriales et suscite l’émergence de nombreux dispositifs de protection. Les tensions entre attractivité et protection complexifient la gestion du territoire en multipliant les acteurs et les usages concurrents. Le contexte décisionnel des acteurs de ce territoire est bien celui d’un univers controversé. Les contributions à ce numéro ont pour objectifs d’éclairer cet univers en proposant des analyses pluridisciplinaires sur : 1- une mise en perspective historique et critique de ce qui fonde l’attractivité du territoire ; 2- une analyse du rôle des zonages dans la gestion du foncier au centre des tensions entre attractivité et protection ; 3- une approche des stratégies d’acteurs en recherche de compromis pour gérer cette tension. Un article varia sur un tout autre thème complète ce numéro, étude d’un vignoble catalan, le Penedès qui, entre Tarragone et Barcelone, subit une pression foncière importante. Différents outils et stratégies de protection sont examinés. Cadre d’une évolution de la maquette intérieure, ce numéro est également l’occasion d’un anniversaire, celui des vingt ans de la « reprise » de la Revue géographique des Pyrénées et du Sud-Ouest sous un nouveau nom, Sud-Ouest Européen. Un texte rappelle les origines de cette renaissance et donne quelques jalons de l’évolution de la revue au cours de ces deux décennies, s’interrogeant aussi sur son devenir

Multiomic analysis of malignant pleural mesothelioma identifies molecular axes and specialized tumor profiles driving intertumor heterogeneity

International audienceAbstract Malignant pleural mesothelioma (MPM) is an aggressive cancer with rising incidence and challenging clinical management. Through a large series of whole-genome sequencing data, integrated with transcriptomic and epigenomic data using multiomics factor analysis, we demonstrate that the current World Health Organization classification only accounts for up to 10% of interpatient molecular differences. Instead, the MESOMICS project paves the way for a morphomolecular classification of MPM based on four dimensions: ploidy, tumor cell morphology, adaptive immune response and CpG island methylator profile. We show that these four dimensions are complementary, capture major interpatient molecular differences and are delimited by extreme phenotypes that—in the case of the interdependent tumor cell morphology and adapted immune response—reflect tumor specialization. These findings unearth the interplay between MPM functional biology and its genomic history, and provide insights into the variations observed in the clinical behavior of patients with MPM

Outcomes of Early Versus Late Tracheostomy in Patients With COVID-19: A Multinational Cohort Study.

UNLABELLED: Timing of tracheostomy in patients with COVID-19 has attracted substantial attention. Initial guidelines recommended delaying or avoiding tracheostomy due to the potential for particle aerosolization and theoretical risk to providers. However, early tracheostomy could improve patient outcomes and alleviate resource shortages. This study compares outcomes in a diverse population of hospitalized COVID-19 patients who underwent tracheostomy either early (within 14 d of intubation) or late (more than 14 d after intubation). DESIGN: International multi-institute retrospective cohort study. SETTING: Thirteen hospitals in Bolivia, Brazil, Spain, and the United States. PATIENTS: Hospitalized patients with COVID-19 undergoing early or late tracheostomy between March 1, 2020, and March 31, 2021. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: A total of 549 patients from 13 hospitals in four countries were included in the final analysis. Multivariable regression analysis showed that early tracheostomy was associated with a 12-day decrease in time on mechanical ventilation (95% CI, -16 to -8; p \u3c 0.001). Further, ICU and hospital lengths of stay in patients undergoing early tracheostomy were 15 days (95% CI, -23 to -9 d; p \u3c 0.001) and 22 days (95% CI, -31 to -12 d) shorter, respectively. In contrast, early tracheostomy patients experienced lower risk-adjusted survival at 30-day post-admission (hazard ratio, 3.0; 95% CI, 1.8-5.2). Differences in 90-day post-admission survival were not identified. CONCLUSIONS: COVID-19 patients undergoing tracheostomy within 14 days of intubation have reduced ventilator dependence as well as reduced lengths of stay. However, early tracheostomy patients experienced lower 30-day survival. Future efforts should identify patients most likely to benefit from early tracheostomy while accounting for location-specific capacity

Outcomes of Early Versus Late Tracheostomy in Patients With COVID-19: A Multinational Cohort Study

Objectives:. Timing of tracheostomy in patients with COVID-19 has attracted substantial attention. Initial guidelines recommended delaying or avoiding tracheostomy due to the potential for particle aerosolization and theoretical risk to providers. However, early tracheostomy could improve patient outcomes and alleviate resource shortages. This study compares outcomes in a diverse population of hospitalized COVID-19 patients who underwent tracheostomy either “early” (within 14 d of intubation) or “late” (more than 14 d after intubation). Design:. International multi-institute retrospective cohort study. Setting:. Thirteen hospitals in Bolivia, Brazil, Spain, and the United States. Patients:. Hospitalized patients with COVID-19 undergoing early or late tracheostomy between March 1, 2020, and March 31, 2021. Interventions:. Not applicable. Measurements and Main Results:. A total of 549 patients from 13 hospitals in four countries were included in the final analysis. Multivariable regression analysis showed that early tracheostomy was associated with a 12-day decrease in time on mechanical ventilation (95% CI, −16 to −8; p < 0.001). Further, ICU and hospital lengths of stay in patients undergoing early tracheostomy were 15 days (95% CI, −23 to −9 d; p < 0.001) and 22 days (95% CI, −31 to −12 d) shorter, respectively. In contrast, early tracheostomy patients experienced lower risk-adjusted survival at 30-day post-admission (hazard ratio, 3.0; 95% CI, 1.8−5.2). Differences in 90-day post-admission survival were not identified. Conclusions:. COVID-19 patients undergoing tracheostomy within 14 days of intubation have reduced ventilator dependence as well as reduced lengths of stay. However, early tracheostomy patients experienced lower 30-day survival. Future efforts should identify patients most likely to benefit from early tracheostomy while accounting for location-specific capacity