Predicting rice (Oryza sativa) productivity under future climates is important for global food security. Ecophysiological crop models in combination with climate model outputs are commonly used in ...yield prediction, but uncertainties associated with crop models remain largely unquantified. We evaluated 13 rice models against multi‐year experimental yield data at four sites with diverse climatic conditions in Asia and examined whether different modeling approaches on major physiological processes attribute to the uncertainties of prediction to field measured yields and to the uncertainties of sensitivity to changes in temperature and CO₂concentration CO₂. We also examined whether a use of an ensemble of crop models can reduce the uncertainties. Individual models did not consistently reproduce both experimental and regional yields well, and uncertainty was larger at the warmest and coolest sites. The variation in yield projections was larger among crop models than variation resulting from 16 global climate model‐based scenarios. However, the mean of predictions of all crop models reproduced experimental data, with an uncertainty of less than 10% of measured yields. Using an ensemble of eight models calibrated only for phenology or five models calibrated in detail resulted in the uncertainty equivalent to that of the measured yield in well‐controlled agronomic field experiments. Sensitivity analysis indicates the necessity to improve the accuracy in predicting both biomass and harvest index in response to increasing CO₂ and temperature.
En Haïti, les systèmes agricoles sont fortement vulnérables au changement climatique. Cette étude vise à analyser la pertinence d’une démarche de co-conception de stratégies d’adaptation des ...exploitations agricoles au changement climatique dans une zone hautement vulnérable telle que Haïti. Menée à Saint Michel de l’Attalaye, l’étude reposait : (i) sur la réalisation d’un diagnostic des performances technico-économiques de 24 exploitations représentatives des trois principaux types de stratégies d’adaptation observées, et (ii) sur la co-conception de stratégies innovantes avec un échantillon plus réduit de 9 agriculteurs. Les résultats de l’étude montrent que les performances initiales des 24 exploitations en termes de couverture des besoins caloriques du ménage, revenus, et émissions de gaz à effet de serre sont différentes pour les trois types de stratégies. La diversification des systèmes de production agricole joue un rôle crucial dans les performances mesurées. Les stratégies proposées par les 9 producteurs visent à accroître cette diversification tout en renforçant la place de la canne à sucre dans les systèmes de production, mais les changements pensés sont incrémentaux. D’autres boucles de co-conception pourraient être envisagées pour explorer avec les producteurs des changements de rupture articulant augmentation des capacités de production des exploitations et adaptation au changement climatique. Cette étude pilote en Haïti pourrait être répliquée dans d’autres zones hautement vulnérables afin de co-concevoir des systèmes innovants tenant compte des contraintes spécifiques auxquelles sont exposés les agriculteurs.
In Haiti, agricultural systems are highly vulnerable to climate change. This study aims to assess the relevance of a process of co-design of climate change adaptation strategies with producers in a highly vulnerable zone such as Haïti. Conducted in Saint Michel de l’Attalaye, the study was based on: (i) a diagnosis of the technical and economic performance of 24 farms representative of the three main types of adaptation strategies observed, and (ii) the co-design of innovative strategies with a smaller sample of 9 farmers. The results of the study show that the initial performances of the 24 farms in terms of covering family caloric needs, income, and greenhouse gas emissions are different for the three types of strategies. The diversification of agricultural production systems plays a crucial role in the performance measured. The strategies proposed by the 9 producers aim to increase this diversification while increasing sugar cane area in their production systems; however the changes thought out are incremental. More co-design loops could be considered to explore with farmers disruptive changes that would both favor an increase in production capacities of farms and climate change adaptation. This pilot study in Haïti could be replicated in other highly vulnerable areas to co-design innovative systems taking into account the specific constraints to which farmers are exposed.
To reduce the risks of climate change, governments agreed in the Paris Agreement to limit global temperature rise to less than 2.0 °C above pre-industrial levels, with the ambition to keep warming to ...1.5 °C. Charting appropriate mitigation responses requires information on the costs of mitigating versus associated damages for the two levels of warming. In this assessment, a critical consideration is the impact on crop yields and yield variability in regions currently challenged by food insecurity. The current study assessed impacts of 1.5 °C versus 2.0 °C on yields of maize, pearl millet and sorghum in the West African Sudan Savanna using two crop models that were calibrated with common varieties from experiments in the region with management reflecting a range of typical sowing windows. As sustainable intensification is promoted in the region for improving food security, simulations were conducted for both current fertilizer use and for an intensification case (fertility not limiting). With current fertilizer use, results indicated 2% units higher losses for maize and sorghum with 2.0 °C compared to 1.5 °C warming, with no change in millet yields for either scenario. In the intensification case, yield losses due to climate change were larger than with current fertilizer levels. However, despite the larger losses, yields were always two to three times higher with intensification, irrespective of the warming scenario. Though yield variability increased with intensification, there was no interaction with warming scenario. Risk and market analysis are needed to extend these results to understand implications for food security.
The expansion of the biologics pipeline depends on the identification of candidate proteins for clinical trials. Speed is one of the critical issues, and the rapid production of high quality, ...research-grade material for preclinical studies by transient gene expression (TGE) is addressing this factor in an impressive way: following DNA transfection, the production phase for TGE is usually 2-10 days. Recombinant proteins (r-proteins) produced by TGE can therefore enter the drug development and screening process in a very short time--weeks. With “classical” approaches to protein expression from mammalian cells, it takes months to establish a productive host cell line. This article summarizes efforts in industry and academia to use TGE to produce tens to hundreds of milligrams of r-proteins for either fundamental research or preclinical studies.
La diversification des cultures est un des leviers qui pourraient contribuer à stabiliser, voire améliorer, les rendements dans les régions soudano-sahéliennes contraintes par des conditions ...climatiques semi-arides et des sols très faiblement fertiles. Elle peut permettre aussi d’atténuer les risques liés aux marchés. Cette diversification peut être mise en œuvre par la pratique des associations et des rotations ainsi que par l’enrichissement de celles-ci avec de nouvelles espèces. Pendant trois années d’expérimentation, nous avons comparé sept espèces, dont quatre légumineuses y compris le haricot mungo, cultivées seules ou en association avec le sorgho. Le haricot mungo est apparu comme une espèce très bien adaptée aux conditions semi-arides du Burkina Faso. Parmi les sept espèces testées, c’est celle qui a produit le plus de grains, entre 0,8 et 1,8 t ha
−1
en culture pure et entre 0,35 et 0.9 t ha
−1
en association avec le sorgho. Nos résultats confirment aussi le gain de rendement de la culture de sorgho associée avec les légumineuses par rapport à la culture pure. Vingt-cinq producteurs du centre nord du Burkina Faso ont testé le haricot mungo dans leurs parcelles et apprécié sa productivité et sa rusticité. Ils ont obtenu un rendement moyen de 0,7 t ha
−1
. Toutefois, l’absence de marché, par comparaison au niébé, reste un frein à sa diffusion.
Crop diversification is one of the levers that could help stabilize or even improve yields in the Sudano-Sahelian regions, which are constrained by semi-arid climatic conditions and very low soil fertility. It can also help mitigate market risks. This diversification can be implemented through the practice of associations and rotations, as well as by enriching them with new crop species. During three years of experimentation, we compared seven species, of which four legumes including mungbean, grown in association with sorghum or in pure stand. Mungbean appeared to be a species very well adapted to the semi-arid conditions of Burkina Faso. Of the seven species tested, it produced the most grain on average, between 0.8 and 1.8 t ha
−1
in pure cultivation and between 0.35 and 0.9 t ha
−1
in association with sorghum. Our results also confirm the yield advantage of growing sorghum in association with legumes over pure cultivation. Twenty-five producers in north-central Burkina Faso tested mungbean in their plots and confirmed its productivity and hardiness. They obtained an average yield of 0.7 t ha
−1
. However, the lack of a market compared to cowpea remains a barrier to its dissemination.
Soil nutrient deficiency and rainfall variability impair the production of sorghum (Sorghum bicolor (L). Moench) in Sudano-Sahelian zone. The aim is to study the environmental factors that can ...determine the effect of fertilizer application on sorghum grain yield and to formulate tailored fertilization strategies according to sorghum varieties (hybrid and open pollinated improved varieties) and environmental context. Field experiments were conducted during the 2015 and 2016 growing seasons in Nioro du Rip and in Sinthiou Malème (Senegal). In a randomized complete block design arranged in a split-plot with four replications, three factors were tested: sorghum genotype (G: Fadda, Faourou, Soumalemba and Soumba with different cycle lengths), environment (E: irrigation and rainfed, different soil types and fertility levels), and fertilization management (M: five different combinations of application dose and application time) including T1 = no fertilizer applied; T2 (recommended practice, 100%) = 150 kg/ha of NPK (15-15-15) at emergence + 50 Kg/ha of urea (46%) at tillering + 50 kg/ha of urea at stem extension; T3 = 50% T2; T4 (100% delay) = 150 kg/ha of NPK +50 kg/ha of urea at stem extension +50 kg/ha of urea at heading ; T5 = 50% T4. Results showed that: (i) in most environments, stressed plants under late application treatments (T4 and T5) recovered biomass once the fertilizer was applied (ii); grain yield with T5 was higher than with T4 under well-watered conditions (sufficient and well distributed rainfall and eventual complementary irrigations) ; (iii) Fadda, a hybrid, responded differently to fertilization than the other varieties only for biomass production, (iv) late fertilizer application treatment (T4) gave higher grain yield than the recommended practice (T2) in the environment with low yield potential, and (v) long cycle duration genotypes benefited better from late fertilization compared to short cycle duration genotypes. This study showed that under Sudano-Sahelian conditions late fertilization of sorghum can be beneficial to grain yield if the rainy season has a slow start, depending on sorghum genotypes (i.e., cycle length), and on the initial N content of the soil.
For most biophysical domains, differences in model structures are seldom quantified. Here, we used a taxonomy-based approach to characterise thirteen rice models. Classification keys and binary ...attributes for each key were identified, and models were categorised into five clusters using a binary similarity measure and the unweighted pair-group method with arithmetic mean. Principal component analysis was performed on model outputs at four sites. Results indicated that (i) differences in structure often resulted in similar predictions and (ii) similar structures can lead to large differences in model outputs. User subjectivity during calibration may have hidden expected relationships between model structure and behaviour. This explanation, if confirmed, highlights the need for shared protocols to reduce the degrees of freedom during calibration, and to limit, in turn, the risk that user subjectivity influences model performance.
•A taxonomy-based approach was used to classify AgMIP rice simulation models.•Different model structures often resulted in similar outputs.•Similar structures often led to large differences in outputs.•User subjectivity likely hides relationships between model structure and behaviour.•Shared protocols are still needed to limit the risks during calibration.
Climate change is estimated to exacerbate existing challenges faced by smallholder farmers in Sub-Sahara Africa. However, limited studies quantify the extent of variation in climate change impact ...under these systems at the local scale. The Decision Support System for Agro-technological Transfer (DSSAT) was used to quantify variation in climate change impacts on maize yield under current agricultural practices in semi-arid regions of Senegal (Nioro du Rip) and Ghana (Navrongo and Tamale). Multi-benchmark climate models (Mid-Century, 2040–2069 for two Representative Concentration Pathways, RCP4.5 and RCP8.5), and multiple soil and management information from agronomic surveys were used as input for DSSAT. The average impact of climate scenarios on grain yield among farms ranged between −9% and −39% across sites. Substantial variation in climate response exists across farms in the same farming zone with relative standard deviations from 8% to 117% at Nioro du Rip, 13% to 64% in Navrongo and 9% to 37% in Tamale across climate models. Variations in fertilizer application, planting dates and soil types explained the variation in the impact among farms. This study provides insight into the complexities of the impact of climate scenarios on maize yield and the need for better representation of heterogeneous farming systems for optimized outcomes in adaptation and resilience planning in smallholder systems.
Previous studies have shown that activation of the signal transducer and activator of transcription 5 (STAT5) plays an essential role in leukemogenesis mediated through constitutive activated protein ...tyrosine kinases (PTK). Because PIM-1 is a STAT5 target gene, we analyzed the role of the family of PIM serine/threonine kinases (PIM-1 to PIM-3) in PTK-mediated transformation of hematopoietic cells. Ba/F3 cells transformed to growth factor independence by various oncogenic PTKs (TEL/JAK2, TEL/TRKC, TEL/ABL, BCR/ABL, FLT3-ITD, and H4/PDGFbetaR) show abundant expression of PIM-1 and PIM-2. Suppression of PIM-1 activity had a negligible effect on transformation. In contrast, expression of kinase-dead PIM-2 mutant (PIM-2KD) led to a rapid decline of survival in Ba/F3 cells transformed by FLT3-ITD but not by other oncogenic PTKs tested. Coexpression of PIM-1KD and PIM-2KD abrogated growth factor-independent growth of Ba/F3 transformed by several PTKs, including BCR/ABL. Targeted down-regulation of PIM-2 by RNA interference (RNAi) selectively abrogated survival of Ba/F3 cells transformed by various Fms-like tyrosine kinase 3 (FLT3)-activating mutants internal tandem duplication (ITD) and kinase domain and attenuated growth of human cell lines containing FLT3 mutations. Interestingly, cells transformed by FLT3 and BCR/ABL mutations that confer resistance to small-molecule tyrosine kinase inhibitors were still sensitive to knockdown of PIM-2, or PIM-1 and PIM-2 by RNAi. Our observations indicate that combined inactivation of PIM-1 and PIM-2 interferes with oncogenic PTKs and suggest that PIMs are alternative therapeutic targets in PTK-mediated leukemia. Targeting the PIM kinase family could provide a new avenue to overcome resistance against small-molecule tyrosine kinase inhibitors.
Apoptotic cell death often requires caspases. Caspases are part of a family of related molecules including also paracaspases and metacaspases. Are molecules of this family generally involved in cell ...death? More specifically, do non-apoptotic caspase-independent types of cell death require paracaspases or metacaspases? Dictyostelium discoideum lends itself well to answering these questions because 1) it undergoes non-apoptotic developmental cell death of a vacuolar autophagic type and 2) it bears neither caspase nor metacaspase genes and apparently only one paracaspase gene. This only paracaspase gene can be inactivated by homologous recombination. Paracaspase-null clones were thus obtained in each of four distinct Dictyostelium strains. These clones were tested in two systems, developmental stalk cell death in vivo and vacuolar autophagic cell death in a monolayer system mimicking developmental cell death. Compared with parent cells, all of the paracaspase-null cells showed unaltered cell death in both test systems. In addition, paracaspase inactivation led to no alteration in development or interaction with a range of bacteria. Thus, in Dictyostelium, vacuolar programmed cell death in development and in a monolayer model in vitro would seem not to require paracaspase. To our knowledge, this is the first instance of developmental programmed cell death shown to be independent of any caspase, paracaspase or metacaspase. These results have implications as to the relationship in evolution between cell death and the caspase family.
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