Une nouvelle histoire du café

Le café est aujourd?hui la première richesse de nombreux pays tropicaux. Seules deux espèces sont cultivées, qui produisent les célèbres Arabica et Robusta. Mais il existe au total près de 120 espèces sauvages, qui ont colonisé en 400000 ans toute l?Afrique équatoriale et la région malgache à partir de leur origine, en Basse Guinée. C?est ce que montre une récente étude de chercheurs de l?IRD et de leur partenaire brésilien 1, grâce au séquençage de l?ADN de 26 espèces. Jusque là, du fait de la présence des caféiers en Afrique, à Madagascar et en Inde, les botanistes pensaient que les arbustes provenaient de la corne de l?Afrique, avant que le supercontinent Gondwana ne se disloque, il y a plus de 100 millions d?années. Ces travaux réorientent les recherches sur le génome du café, en vue de l?amélioration de cette plante d?un grand intérêt agronomique et socio-économiquebitstream/item/123108/1/Une-nouvelle.pd

The Likelihood Ratio Test and Full Bayesian Significance Test under small sample sizes for contingency tables

Hypothesis testing in contingency tables is usually based on asymptotic results, thereby restricting its proper use to large samples. To study these tests in small samples, we consider the likelihood ratio test and define an accurate index, the P-value, for the celebrated hypotheses of homogeneity, independence, and Hardy-Weinberg equilibrium. The aim is to understand the use of the asymptotic results of the frequentist Likelihood Ratio Test and the Bayesian FBST -- Full Bayesian Significance Test -- under small-sample scenarios. The proposed exact P-value is used as a benchmark to understand the other indices. We perform analysis in different scenarios, considering different sample sizes and different table dimensions. The exact Fisher test for $2 \times 2$ tables that drastically reduces the sample space is also discussed. The main message of this paper is that all indices have very similar behavior, so the tests based on asymptotic results are very good to be used in any circumstance, even with small sample sizes

How many green jobs are there in electricity generation? A replicable quantification method for developing countries under data constraints

Assessing the scale of green jobs and the socioeconomic effects of the energy transition is relevant and timely, while clear, comparable methodologies are still scarce. The discussion around just transitions, and the extent to which renewable energy creates more positive socioeconomic impacts than fossil fuels, increasingly attracts policymakers' and researchers' attention. However, data constraints, particularly in developing economies, expose a relevant gap in providing quantitative evidence for such discussions. This is especially relevant in countries with outstanding potential for renewable deployments, such as the case of Brazil. Existing data usually is considerably aggregated into activities irrespectively of technology or Greenhouse gas emission profile, and general international frameworks for such quantification may prove inadequate. In this paper, we propose a replicable data triangulation approach to disaggregate electricity jobs and wages into renewable and non-renewable electricity generation sources applied to the case of Brazil, using national accounts data, energy generation statistics and electricity-source specific employment coefficients from where data is available. One can use the resulting dataset either purely as the current scale of renewable and non-renewable electricity jobs and income or as the database for further modelling projections, particularly macroeconomic, multisectoral models, namely input-output and computable general equilibrium models

T cell control of SARS-CoV-2: When, which, and where?

Efficient immune protection against viruses such as SARS-CoV-2 requires the coordinated activity of innate immunity, B and T cells. Accumulating data point to a critical role for T cells not only in the clearance of established infection, but also for aborting viral replication independently of humoral immunity. Here we review the evidence supporting the contribution of antiviral T cells and consider which of their qualitative features favour efficient control of infection. We highlight how studies of SARS-CoV-2 and other coronaviridae in animals and humans have provided important lessons on the optimal timing (When), functionality and specificity (Which), and location (Where) of antiviral T cells. We discuss the clinical implications, particularly for the development of next-generation vaccines, and emphasise areas requiring further study