313 research outputs found

    Physiological and genetic control of transpiration efficiency in African rice, Oryza glaberrima Steud

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    Improving crop water use efficiency, the amount of carbon assimilated as biomass per unit of water used by a plant, is of major importance as water for agriculture becomes scarcer. In rice, the genetic bases of transpiration efficiency, the derivation of water use efficiency at the whole-plant scale, and its putative component trait transpiration restriction under high evaporative demand remain unknown. These traits were measured in 2019 in a panel of 147 African rice (Oryza glaberrima) genotypes known to be potential sources of tolerance genes to biotic and abiotic stresses. Our results reveal that higher transpiration efficiency is associated with transpiration restriction in African rice. Detailed measurements in a subset of highly contrasted genotypes in terms of biomass accumulation and transpiration confirmed these associations and suggested that root to shoot ratio played an important role in transpiration restriction. Genome wide association studies identified marker-trait associations for transpiration response to evaporative demand, transpiration efficiency, and its residuals, with links to genes involved in water transport and cell wall patterning. Our data suggest that root-shoot partitioning is an important component of transpiration restriction that has a positive effect on transpiration efficiency in African rice. Both traits are heritable and define targets for breeding rice with improved water use strategies.This work was supported by the Institut de Recherche pour le Développement, the CGIAR Research Program (CRP) on rice-agrifood systems (RICE, 2017-2022) and the Agence Nationale de la Recherche (grant ANR-17-MPGA-0011 to VV). Financial support by the Access to Research Infrastructures activity in the Horizon 2020 Programme of the EU (EPPN2020 Grant Agreement 731013) is gratefully acknowledged. PA was supported by a doctoral fellowship from the French Ministry of Higher Education. BEE was supported by the Centre National de la Recherche Scientifique et Technologique of Gabon. The authors acknowledge the IRD iTrop HPC (South Green Platform) at IRD Montpellier for providing HPC resources (https://bioinfo.ird.fr, http://www.southgreen.fr)

    Rural veterinarian's perception and practices in terms of biosecurity across three European countries

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    The implementation of biosecurity measures in the animal health and production context is quite broad and aims at limiting the risk of introduction and spread of diseases. Veterinarians play a major role in biosecurity as key informants on the subject for cattle holders, key players in terms of disease prevention/control and eradication programs, as well as key risk factor in terms of disease dissemination. Many biosecurity studies have highlighted professional visitors such as veterinary practitioners as representing a high-risk factor in terms of disease introduction in animal facilities but, to date, very few studies have focused on the implementation level of biosecurity measures by veterinarians. An online survey was implemented in three European countries (Belgium, France and Spain) to assess the behaviour of rural veterinarians towards biosecurity, as well as their implementation level of the biosecurity measures. A descriptive analysis of data and a scoring system were applied to assess the implementation level of measures. The influence of different factors on the implementation level of biosecurity measures was investigated through a negative binomial regression model. The study identified different strengths, weaknesses, possible constraints and solutions in terms of veterinary perspectives. Veterinarians are considered as key informants by the farmers and could therefore play a more active role in terms of guidance and improvement of biosecurity at farm level. Based on the survey outcomes, two factors seemed to influence significantly the implementation level of measures: the country where he/she practices and the veterinarian's perception level of biosecurity. The biosecurity stages with the lowest application level, therefore representing the biggest threats, were bio-exclusion (increasing the risk of disease introduction) and biocontainment (increasing the risk of inter-herd transmission).info:eu-repo/semantics/acceptedVersio

    The Development of Functional Overreaching Is Associated with a Faster Heart Rate Recovery in Endurance Athletes

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    Purpose The aim of the study was to investigate whether heart rate recovery (HRR) may represent an effective marker of functional overreaching (f-OR) in endurance athletes. Methods and Results Thirty-one experienced male triathletes were tested (10 control and 21 overload subjects) before (Pre), and immediately after an overload training period (Mid) and after a 2-week taper (Post). Physiological responses were assessed during an incremental cycling protocol to exhaustion, including heart rate, catecholamine release and blood lactate concentration. Ten participants from the overload group developed signs of f-OR at Mid (i.e. -2.1 ± 0.8% change in performance associated with concomitant high perceived fatigue). Additionally, only the f-OR group demonstrated a 99% chance of increase in HRR during the overload period (+8 ± 5 bpm, large effect size). Concomitantly, this group also revealed a >80% chance of decreasing blood lactate (-11 ± 14%, large), plasma norepinephrine (-12 ± 37%, small) and plasma epinephrine peak concentrations (-51 ± 22%, moderate). These blood measures returned to baseline levels at Post. HRR change was negatively correlated to changes in performance, peak HR and peak blood metabolites concentrations. Conclusion These findings suggest that i) a faster HRR is not systematically associated with improved physical performance, ii) changes in HRR should be interpreted in the context of the specific training phase, the athletes perceived level of fatigue and the performance response; and, iii) the faster HRR associated with f-OR may be induced by a decreased central commandand by a lower chemoreflex activity

    Beyond Copenhagen: A Realistic Climate Policy in a Fragmented World

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    In this paper we argue that the financial provisions of the Copenhagen Accord, if used primarily to mitigate greenhouse gas (GHGs) emissions, could compensate the lack of more energetic action on the domestic mitigation side. In order to maximize the mitigation potential, the Copenhagen Green Climate Fund (CGCF) should be transformed into the International Bank for Emissions Allowance Acquisition (IBEAA) envisaged by Bradford ( 2008 ). We estimate that 50 percent of the CGCF in 2020 (50 US billions) could finance from 2.1 to 3.3 Gt CO2-eq emission reductions, depending on the domestic mitigation effort of Annex I and Non-Annex I countries. We construct a matrix that shows the level of GHGs emissions in 2020 under all possible combinations of abatement pledges and international mitigation financing, thus highlighting a rich set of options to reach the same level of GHGs emissions in 2020

    Increased percentage of T cells with the expression of CD127 and CD132 in hypertrophic adenoid in children with otitis media with effusion

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    The hypertrophic adenoid may promote chronic suppurative otitis media in children as it fulfills its immune function. The number of lymphocytes in the adenoid and their cooperation in the immune response depend of on their proliferation and migration to the effector sites. Interleukin 7 (IL-7) is essential for the normal development and function lymphocytes. IL-7 plays pivotal role for activation and proliferation of T and B cells. The heterodimeric interleukin-7 receptor (IL-7R) is composed of the IL-7Rα (127) and the common cytokine receptor γc (CD132). The aim of this study was to evaluate the percentage of lymphocytes T (CD4+ and CD8+) with IL-7R (CD127 and CD132) expression in hypertrophic adenoid in children suffering with otitis media with effusion for a duration of 3 months. Adenoid excised due to hypertrophy with or without chronic otitis media with effusion was used as study material. CD4+ CD127+, CD4+132+, CD8+CD127+ and CD8+CD132+ cell subpopulations were identified using monoclonal antibodies and flow cytometry. The percentage of CD4+ and CD8+ T cells with CD127 receptor expression in hypertrophic adenoid of children with otitis media with effusion was statistically significantly higher than in hypertrophic adenoid group. The percentage of CD4+ T cells with CD132 expression in the study group was statistically significantly higher than in the reference group. The percentage of CD8+ T cells with CD132+ expression was not statistically different in both groups. The increased percentage of T lymphocytes with IL-7R expression (CD127 and CD132) in hypertrophic adenoid seems to influence the quantity of lymphocytes and upset the immunological function of tonsils which can influence the course of otitis media with effusion
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