Paul Sabatier University

About: Paul Sabatier University is a education organization based out in Toulouse, France. It is known for research contribution in the topics: Population & Adipose tissue. The organization has 15431 authors who have published 23386 publications receiving 858364 citations.

Testing metabolic ecology theory for allometric scaling of tree size, growth and mortality in tropical forests

Abstract: The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 oldgrowth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test the theory’s predictions. We also developed a set of alternative predictions that retained some assumptions of metabolic ecology while also considering how availability of a key limiting resource, light, changes with tree size. Our results show that there are no universal scaling relationships of growth or mortality with size among trees in tropical forests. Observed patterns were consistent with our alternative model in the one site where we had the data necessary to evaluate it, and were inconsistent with the predictions of metabolic ecology in all forests.

Interferometric data reduction with AMBER/VLTI. Principle, estimators, and illustration.

Abstract: Aims. In this paper, we present an innovative data reduction method for single-mode interferometry. It has been specifically developed for the AMBER instrument, the three-beam combiner of the Very Large Telescope Interferometer, but it can be derived for any single-mode interferometer. Methods. The algorithm is based on a direct modelling of the fringes in the detector plane. As such, it requires a preliminary calibration of the instrument in order to obtain the calibration matrix that builds the linear relationship between the interferogram and the interferometric observable, which is the complex visibility. Once the calibration procedure has been performed, the signal processing appears to be a classical least-square determination of a linear inverse problem. From the estimated complex visibility, we derive the squared visibility, the closure phase, and the spectral differential phase. Results. The data reduction procedures have been gathered into the so-called amdlib software, now available for the community, and are presented in this paper. Furthermore, each step in this original algorithm is illustrated and discussed from various on-sky observations conducted with the VLTI, with a focus on the control of the data quality and the effective execution of the data reduction procedures. We point out the present limited performances of the instrument due to VLTI instrumental vibrations which are difficult to calibrate.

How many dimensions are needed to accurately assess functional diversity? A pragmatic approach for assessing the quality of functional spaces

Abstract: Aim Functional diversity is a key facet of biodiversity that is increasingly being measured to quantify its changes following disturbance and to understand its effects on ecosystem functioning. Assessing the functional diversity of assemblages based on species traits requires the building of a functional space (dendrogram or multidimensional space) where indices will be computed. However, there is still no consensus on the best method for measuring the quality of functional spaces. Innovation Here we propose a framework for evaluating the quality of a functional space (i.e. the extent to which it is a faithful representation of the initial functional trait values). Using simulated datasets, we analysed the influence of the number and type of functional traits used and of the number of species studied on the identity and quality of the best functional space. We also tested whether the quality of the functional space affects functional diversity patterns in local assemblages, using simulated datasets and a real study case. Main conclusions The quality of functional space strongly varied between situations. Spaces having at least four dimensions had the highest quality, while functional dendrograms and two-dimensional functional spaces always had a low quality. Importantly, we showed that using a poor-quality functional space could led to a biased assessment of functional diversity and false ecological conclusions. Therefore, we advise a pragmatic approach consisting of computing all the possible functional spaces and selecting the most parsimonious one.

Nivolumab or nivolumab plus ipilimumab in patients with relapsed malignant pleural mesothelioma (IFCT-1501 MAPS2): a multicentre, open-label, randomised, non-comparative, phase 2 trial

Abstract: Summary Background There is no recommended therapy for malignant pleural mesothelioma that has progressed after first-line pemetrexed and platinum-based chemotherapy. Disease control has been less than 30% in all previous studies of second-line drugs. Preliminary results have suggested that anti-programmed cell death 1 (PD-1) monoclonal antibody could be efficacious in these patients. We thus aimed to prospectively assess the anti-PD-1 monoclonal antibody alone or in combination with anti-cytotoxic T-lymphocyte protein 4 (CTLA-4) antibody in patients with malignant pleural mesothelioma. Methods This multicentre randomised, non-comparative, open-label, phase 2 trial was done at 21 hospitals in France. Eligible patients were aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0–1, histologically proven malignant pleural mesothelioma progressing after first-line or second-line pemetrexed and platinum-based treatments, measurable disease by CT, and life expectancy greater than 12 weeks. Patients were randomly allocated (1:1) to receive intravenous nivolumab (3 mg/kg bodyweight) every 2 weeks, or intravenous nivolumab (3 mg/kg every 2 weeks) plus intravenous ipilimumab (1 mg/kg every 6 weeks), given until progression or unacceptable toxicity. Central randomisation was stratified by histology (epithelioid vs non-epithelioid), treatment line (second line vs third line), and chemosensitivity to previous treatment (progression ≥3 months vs Findings Between March 24 and August 25, 2016, 125 eligible patients were recruited and assigned to either nivolumab (n=63) or nivolumab plus ipilimumab (n=62). In the first 108 eligible patients, 12-week disease control was achieved by 24 (44%; 95% CI 31–58) of 54 patients in the nivolumab group and 27 (50%; 37–63) of 54 patients in the nivolumab plus ipilimumab group. In the intention-to-treat population, 12-week disease control was achieved by 25 (40%; 28–52) of 63 patients in the nivolumab group and 32 (52%; 39–64) of 62 patients in the combination group. Nine (14%) of 63 patients in the nivolumab group and 16 (26%) of 61 patients in the combination group had grade 3–4 toxicities. The most frequent grade 3 adverse events were asthenia (one [2%] in the nivolumab group vs three [5%] in the combination group), asymptomatic increase in aspartate aminotransferase or alanine aminotransferase (none vs four [7%] of each), and asymptomatic lipase increase (two [3%] vs one [2%]). No patients had toxicities leading to death in the nivolumab group, whereas three (5%) of 62 in the combination group did (one fulminant hepatitis, one encephalitis, and one acute kidney failure). Interpretation Anti-PD-1 nivolumab monotherapy or nivolumab plus anti-CTLA-4 ipilimumab combination therapy both showed promising activity in relapsed patients with malignant pleural mesothelioma, without unexpected toxicity. These regimens require confirmation in larger clinical trials. Funding French Cooperative Thoracic Intergroup.

Current status of AlInN layers lattice-matched to GaN for photonics and electronics

Abstract: We report on the current properties of Al1-x InxN (x approximate to 0.18) layers lattice- matched ( LM) to GaN and their specific use to realize nearly strain- free structures for photonic and electronic applications. Following a literature survey of the general properties of AlInN layers, structural and optical properties of thin state- of- the- art AlInN layers LM to GaN are described showing that despite improved structural properties these layers are still characterized by a typical background donor concentration of ( 1 - 5) x 10(18) cm(-3) and a large Stokes shift (similar to 800 meV) between luminescence and absorption edge. The use of these AlInN layers LM to GaN is then exemplified through the properties of GaN/ AlInN multiple quantum wells ( QWs) suitable for near- infrared intersubband applications. A built- in electric field of 3.64MVcm(-1) solely due to spontaneous polarization is deduced from photoluminescence measurements carried out on strain- free single QW heterostructures, a value in good agreement with that deduced from theoretical calculation. Other potentialities regarding optoelectronics are demonstrated through the successful realization of crack- free highly reflective AlInN/ GaN distributed Bragg reflectors ( R > 99%) and high quality factor microcavities ( Q > 2800) likely to be of high interest for short wavelength vertical light emitting devices and fundamental studies on the strong coupling regime between excitons and cavity photons. In this respect, room temperature ( RT) lasing of a LM AlInN/ GaN vertical cavity surface emitting laser under optical pumping is reported. A description of the selective lateral oxidation of AlInN layers for current confinement in nitride- based light emitting devices and the selective chemical etching of oxidized AlInN layers is also given. Finally, the characterization of LM AlInN/ GaN heterojunctions will reveal the potential of such a system for the fabrication of high electron mobility transistors through the report of a high two- dimensional electron gas sheet carrier density ( n(s) similar to 2.6 x 10(13) cm(-2)) combined with a RT mobility mu(e) similar to 1170 cm(2) V-1 s(-1) and a low sheet resistance, R similar to 210 Omega square.