Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
226 result(s) for "Barbier, Nicolas"
Sort by:
Spatial validation reveals poor predictive performance of large-scale ecological mapping models
Mapping aboveground forest biomass is central for assessing the global carbon balance. However, current large-scale maps show strong disparities, despite good validation statistics of their underlying models. Here, we attribute this contradiction to a flaw in the validation methods, which ignore spatial autocorrelation (SAC) in data, leading to overoptimistic assessment of model predictive power. To illustrate this issue, we reproduce the approach of large-scale mapping studies using a massive forest inventory dataset of 11.8 million trees in central Africa to train and validate a random forest model based on multispectral and environmental variables. A standard nonspatial validation method suggests that the model predicts more than half of the forest biomass variation, while spatial validation methods accounting for SAC reveal quasi-null predictive power. This study underscores how a common practice in big data mapping studies shows an apparent high predictive power, even when predictors have poor relationships with the ecological variable of interest, thus possibly leading to erroneous maps and interpretations.
Short-term androgen deprivation therapy combined with radiotherapy as salvage treatment after radical prostatectomy for prostate cancer (GETUG-AFU 16): a 112-month follow-up of a phase 3, randomised trial
Radiotherapy is the standard salvage treatment after radical prostatectomy. To date, the role of androgen deprivation therapy has not been formally shown. In this follow-up study, we aimed to update the results of the GETUG-AFU 16 trial, which assessed the efficacy of radiotherapy plus androgen suppression versus radiotherapy alone. GETUG-AFU 16 was an open-label, multicentre, phase 3, randomised, controlled trial that enrolled men (aged ≥18 years) with Eastern Cooperative Oncology Group performance status of 0 or 1, with histologically confirmed adenocarcinoma of the prostate (but no previous androgen suppression or pelvic radiotherapy), stage pT2, T3, or T4a (bladder neck involvement only) and pN0 or pNx according to the tumour, node, metastasis (TNM) staging system, whose prostate-specific antigen (PSA) concentration increased from 0·1 ng/mL to between 0·2 ng/mL and 2·0 ng/mL after radical prostatectomy, without evidence of clinical disease. Patients were assigned through central randomisation (1:1) to short-term androgen suppression (subcutaneous injection of 10·8 mg goserelin on the first day of irradiation and 3 months later) plus radiotherapy (3D conformal radiotherapy or intensity modulated radiotherapy of 66 Gy in 33 fractions, 5 days a week for 7 weeks) or radiotherapy alone. Randomisation was stratified using a permuted block method (block sizes of two and four) according to investigational site, radiotherapy modality, and prognosis. The primary endpoint was progression-free survival in the intention-to-treat population. This post-hoc one-shot data collection done 4 years after last data cutoff included patients who were alive at the time of the primary analysis and updated long-term patient status by including dates for first local progression, metastatic disease diagnosis, or death (if any of these had occurred) or the date of the last tumour evaluation or last PSA measurement. Survival at 120 months was reported. Late serious adverse effects were assessed. This trial is registered on ClinicalTrials.gov, NCT00423475. Between Oct 19, 2006, and March 30, 2010, 743 patients were randomly assigned, 374 to radiotherapy alone and 369 to radiotherapy plus goserelin. At the time of data cutoff (March 12, 2019), the median follow-up was 112 months (IQR 102–123). The 120-month progression-free survival was 64% (95% CI 58–69) for patients treated with radiotherapy plus goserelin and 49% (43–54) for patients treated with radiotherapy alone (hazard ratio 0·54, 0·43–0·68; stratified log-rank test p<0·0001). Two cases of secondary cancer occurred since the primary analysis, but were not considered to be treatment related. No treatment-related deaths occurred. The 120-month progression-free survival confirmed the results from the primary analysis. Salvage radiotherapy combined with short-term androgen suppression significantly reduced risk of biochemical or clinical progression and death compared with salvage radiotherapy alone. The results of the GETUG-AFU 16 trial confirm the efficacy of androgen suppression plus radiotherapy as salvage treatment in patients with increasing PSA concentration after radical prostatectomy for prostate cancer. The French Health ministry, AstraZeneca, la Ligue Contre le Cancer, and La Ligue de Haute-Savoie.
Lymphoid stroma in all its states
Stromal cells are found in all tissues of the body. Among them, lymphoid stromal cells (LSCs) correspond to the cell subsets found in secondary and tertiary lymphoid organs. LSC heterogeneity has been characterized in depth in mice based on cell-fate mapping, high-resolution imaging and single-cell RNAseq analysis, and more recently in humans despite the difficulty of accessing these rare cell populations. At steady-state, LSCs organize discrete anatomical niches in lymphoid organs and orchestrate adaptive immune response. Studies of LSCs at the single cell level have identified a wide role for these cells in various pathological conditions, including solid tumors, autoimmune diseases, and lymphomas. In this review, we will discuss the diversity and plasticity of LSCs and LSC-like cells as well as their functions in pathological settings, with a focus on cancer and autoimmune diseases. Altogether, it highlights the importance of increasing our understanding of these cells, to use them as a target for novel therapeutic strategies.
Salvage radiotherapy with or without short-term hormone therapy for rising prostate-specific antigen concentration after radical prostatectomy (GETUG-AFU 16): a randomised, multicentre, open-label phase 3 trial
How best to treat rising prostate-specific antigen (PSA) concentration after radical prostatectomy is an urgent clinical question. Salvage radiotherapy delays the need for more aggressive treatment such as long-term androgen suppression, but fewer than half of patients benefit from it. We aimed to establish the effect of adding short-term androgen suppression at the time of salvage radiotherapy on biochemical outcome and overall survival in men with rising PSA following radical prostatectomy. This open-label, multicentre, phase 3, randomised controlled trial, was done in 43 French study centres. We enrolled men (aged ≥18 years) who had received previous treatment for a histologically confirmed adenocarcinoma of the prostate (but no previous androgen deprivation therapy or pelvic radiotherapy), and who had stage pT2, pT3, or pT4a (bladder neck involvement only) in patients who had rising PSA of 0·2 to less than 2·0 μg/L following radical prostatectomy, without evidence of clinical disease. Patients were randomly assigned (1:1) centrally via an interactive web response system to standard salvage radiotherapy (three-dimensional [3D] conformal radiotherapy or intensity modulated radiotherapy, of 66 Gy in 33 fractions 5 days a week for 7 weeks) or radiotherapy plus short-term androgen suppression using 10·8 mg goserelin by subcutaneous injection on the first day of irradiation and 3 months later. Randomisation was stratified using a permuted block method according to investigational site, radiotherapy modality, and prognosis. The primary endpoint was progression-free survival, analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT00423475. Between Oct 19, 2006, and March 30, 2010, 743 patients were randomly assigned, 374 to radiotherapy alone and 369 to radiotherapy plus goserelin. Patients assigned to radiotherapy plus goserelin were significantly more likely than patients in the radiotherapy alone group to be free of biochemical progression or clinical progression at 5 years (80% [95% CI 75–84] vs 62% [57–67]; hazard ratio [HR] 0·50, 95% CI 0·38–0·66; p<0·0001). No additional late adverse events occurred in patients receiving short-term androgen suppression compared with those who received radiotherapy alone. The most frequently occuring acute adverse events related to goserelin were hot flushes, sweating, or both (30 [8%] of 366 patients had a grade 2 or worse event; 30 patients [8%] had hot flushes and five patients [1%] had sweating in the radiotherapy plus goserelin group vs none of 372 patients in the radiotherapy alone group). Three (8%) of 366 patients had grade 3 or worse hot flushes and one patient had grade 3 or worse sweating in the radiotherapy plus goserelin group versus none of 372 patients in the radiotherapy alone group. The most common late adverse events of grade 3 or worse were genitourinary events (29 [8%] in the radiotherapy alone group vs 26 [7%] in the radiotherapy plus goserelin group) and sexual disorders (20 [5%] vs 30 [8%]). No treatment-related deaths occurred. Adding short-term androgen suppression to salvage radiotherapy benefits men who have had radical prostatectomy and whose PSA rises after a postsurgical period when it is undetectable. Radiotherapy combined with short-term androgen suppression could be considered as a reasonable option in this population. French Ministry of Health, AstraZeneca, and La Ligue Contre le Cancer.
Upscaling Forest Biomass from Field to Satellite Measurements: Sources of Errors and Ways to Reduce Them
Forest biomass monitoring is at the core of the research agenda due to the critical importance of forest dynamics in the carbon cycle. However, forest biomass is never directly measured; thus, upscaling it from trees to stand or larger scales (e.g., countries, regions) relies on a series of statistical models that may propagate large errors. Here, we review the main steps usually adopted in forest aboveground biomass mapping, highlighting the major challenges and perspectives. We show that there is room for improvement along the scaling-up chain from field data collection to satellite-based large-scale mapping, which should lead to the adoption of effective practices to better control the propagation of errors. We specifically illustrate how the increasing use of emerging technologies to collect massive amounts of high-quality data may significantly improve the accuracy of forest carbon maps. Furthermore, we discuss how sources of spatially structured biases that directly propagate into remote sensing models need to be better identified and accounted for when extrapolating forest carbon estimates, e.g., through a stratification design. We finally discuss the increasing realism of 3D simulated stands, which, through radiative transfer modelling, may contribute to a better understanding of remote sensing signals and open avenues for the direct calibration of large-scale products, thereby circumventing several current difficulties.
global biogeography of semi-arid periodic vegetation patterns
Vegetation exhibiting landscape-scale regular spatial patterns has been reported for arid and semi-arid areas world-wide. Recent theories state that such structures are bound to low-productivity environments and result from a self-organization process. Our objective was to test this relationship between periodic pattern occurrence and environmental factors at a global scale and to parametrize a predictive distribution model. Arid and semi-arid areas world-wide. We trained an empirical predictive model (Maxent) for the occurrence of periodic vegetation patterns, based on environmental predictors and known occurrences verified on Landsat satellite images. This model allowed us to discover previously unreported pattern locations, and to report the first ever examples of spotted patterns in natural systems. Relationships to the main environmental drivers are discussed. These results confirm that periodic patterned vegetations are ubiquitous at the interface between arid and semi-arid regions. Self-organized patterning appears therefore to be a biome-scale response to environmental conditions, including soil and topography. The set of correlations between vegetation patterns and their environmental conditions presented in this study will need to be reproduced in future modelling attempts.
Pathogenicity and escape to pre-existing immunity of a new genotype of swine influenza H1N2 virus that emerged in France in 2020
In 2020, a new genotype of swine H1N2 influenza virus (H1 av N2–HA 1C.2.4) was identified in France. It rapidly spread within the pig population and supplanted the previously predominant H1 av N1-HA 1C.2.1 virus. To characterize this new genotype which is genetically and antigenically distant from the other H1 av Nx viruses detected in France, an experimental study was conducted to compare the outcomes of H1 av N2 and H1 av N1 infections in pigs and evaluate the protection conferred by the only inactivated vaccine currently licensed in Europe containing an HA 1C (clade 1C.2.2) antigen. Infection with H1 av N2 induced stronger clinical signs and earlier shedding than H1 av N1. The neutralizing antibodies produced following H1 av N2 infection were unable to neutralize H1 av N1, and vice versa, whereas the cellular-mediated immunity cross-reacted. Vaccination slightly altered the impact of H1 av N2 infection at the clinical level, but did not prevent shedding of infectious virus particles. It induced a cellular-mediated immune response towards H1 av N2, but did not produce neutralizing antibodies against this virus. As in vaccinated animals, animals previously infected by H1 av N1 developed a cross-reacting cellular immune response but no neutralizing antibodies against H1 av N2. However, H1 av N1 pre-infection induced a better protection against the H1 av N2 infection than vaccination, probably due to higher levels of non-neutralizing antibodies and a mucosal immunity. Altogether, these results showed that the new H1 av N2 genotype induced a severe respiratory infection and that the actual vaccine was less effective against this H1 av N2-HA 1C.2.4 than against H1 av N1-HA 1C.2.1, which may have contributed to the H1 av N2 epizootic and dissemination in pig farms in France.
Exploring the relation between remotely sensed vertical canopy structure and tree species diversity in Gabon
Mapping tree species diversity is increasingly important in the face of environmental change and biodiversity conservation. We explore a potential way of mapping this diversity by relating forest structure to tree species diversity in Gabon. First, we test the relation between canopy height, as a proxy for niche volume, and tree species diversity. Then, we test the relation between vertical canopy structure, as a proxy for vertical niche occupation, and tree species diversity. We use large footprint full-waveform airborne lidar data collected across four study sites in Gabon (Lopé, Mabounié, Mondah, and Rabi) in combination with in situ estimates of species richness (S) and Shannon diversity (H′). Linear models using canopy height explained 44% and 43% of the variation in S and H′ at the 0.25 ha resolution. Linear models using canopy height and the plant area volume density profile explained 71% of this variation. We demonstrate applications of these models by mapping S and H′ in Mondah using a simulated GEDI-TanDEM-X fusion height product, across the four sites using wall-to-wall airborne lidar data products, and across and between the study sites using ICESat lidar waveforms. The modeling results are encouraging in the context of developing pan-tropical structure-diversity models applicable to data from current and upcoming spaceborne remote sensing missions.
African tropical montane forests store more carbon than was thought
The inaccessibility of African montane forests has hindered efforts to quantify the carbon stored by these ecosystems. A remarkable survey fills this knowledge gap, and highlights the need to preserve such forests. A tree inventory for some of Africa’s most inaccessible ecosystems. African montane forest with trees on a steep incline and low-lying clouds
African tropical montane forests store more carbon than was thought
The inaccessibility of African montane forests has hindered efforts to quantify the carbon stored by these ecosystems. A remarkable survey fills this knowledge gap, and highlights the need to preserve such forests.