Réponses phénologiques du riz irrigué dans le Sahel

Dans le Sahel, les périodes froides causent des pertes de rendement dues à la stérilité des épillets chez le riz cultivé tardivement. Les systèmes de riziculture au Sahel pourront donc bénéficier des hausses de températures. Des températures plus élevées pendant la phase végétative entraîneront des cycles de culture raccourcis, tandis que pendant les périodes froides de la phase reproductive, des températures plus élevées pourront réduire la stérilité. Pour les périodes chaudes, ont attend des effets négatifs sur la production de la biomasse et l'augmentation de la stérilité causée par la chaleur. Sur la base des données phénologiques d'une vaste gamme de matériel génétique collectées au début des années 1990 au Sénégal, un modèle (RIDEV) a été développé pour estimer la durée et la stérilité de multiples variétés de riz dans le Sahel comme une fonction de la date de semis. Cependant, des différences observées entre les cycles observés dans les champs des paysans et ceux évalués par RIDEV ont été rapportées. Cela pourrait s'expliquer soit par des défaillances du modèle, l'évolution variétale et/ ou par le changement climatique. Actuellement, à Ndiaye (zone côtière semi-aride) et Fanaye (zone continentale semi-aride), 10 variétés de riz très différentes sont cultivées toute l'année avec des dates de semis décalées d'un mois en vue de déterminer la durée, le taux d'apparition des feuilles et la stérilité dans les conditions climatiques actuelles. Ces variétés incluent certains des génotypes précédemment observés de même que certaines variétés de référence tolérantes à la chaleur et au froid. Les résultats seront utilisés pour améliorer RIDEV en vue des prédictions des réponses des cultures au changement climatique. Les résultats préliminaires avec une attention particulière sur la dérivation des constantes photothermiques seront présentés pour l'ensemble de la première année et comparés aux résultats issus des années précédentes.(Texte intégral

Climate smart rice innovations to reduce the impact of climate change on the livelihood of value chain actors

Introduction Rice is a major source of nutrients, largely contributing to the food and nutrition security for millions of people in Africa although most countries still rely on huge imports to meet local demand. Extreme temperatures, drought, flooding, and high salinity are climate change related stresses that negatively affect rice yield and grain quality. Thus, tackling these constraints is a critical action to increasing rice self sufficiency in Cameroon and Africa in general. Methods The Africa Rice Center in partnership with the National Agricultural Research and Extension Services of its 28 member States operating within the framework of the Africa-wide Taskforces has developed, tested, validated, and are deploying breeding, agronomic and post-harvest approaches to mitigate the negative impacts of climate change on rice yield and quality in Africa. Results Breeding approaches have led to the development of drought, cold, submergence, stagnation flood, salinity, and anaerobic germination tolerant varieties that are also resistant or tolerant to biotic stresses. These have demonstrated better yields and grain quality under stressed conditions compared to counterparts lacking those specific traits. The system of rice intensification and alternate wetting and drying, mid-season drainage, smart-valleys approach for inland development, solar-powered irrigation system, no-till and rice straw mulching are agronomic approaches developed and these approaches have demonstrated significant increase in yield and grain quality compared to alternative approached under climate change stress conditions. Post-harvest approaches have focused on reducing grain breakages, chalkiness, mycotoxin contamination, insecticide and fungicide use, deforestation and value addition to broken rice and rice milling byproducts using environmentally friendly methods. Post-harvest innovations here include using improved rice parboiling fueled by rice husk, solar-powered hermetic storage systems, processing of fine broken rice into flour for porridges and bakery products and use of rice husk fan-assisted stoves for household cooking and the cottage processing industry. Conclusions and recommendations Although climate change is a serious threat to rice production affecting both yield and quality, African governments will have to implement policy measures that enhance the scaling and adoption of climate smart rice innovation developed by AfricaRice to mitigate the impact of climate change if they aspire to reduce rice imports

Suitable management options to improve the productivity of rice cultivars under salinity stress

Growing rice in saline soils by minimizing damage on growth and yield remains a challenge. We conducted field experiments in the Africa Rice research field located in the Senegal River delta (16° 11ʹ N, 16° 15ʹ W) to study the effects of three management options of fertilization e.g. (i) nitrogen, phosphorus, and potassium fertilization: NPK; (ii) NPK combined with zinc: NPK-Zn, and (iii) NPK combined with gypsum: NPK-gypsum on the soil salinity level, the nutrient uptake and the productivity of different rice cultivars. The whole objective of this study is to determine how zinc or gypsum associated to NPK fertilizer can improve the growth and productivity of rice crop in saline soil. Results showed that the initial soil salinity level was reduced rapidly in plots treated with gypsum. The leaf-K/Na ratio, agronomic nitrogen use efficiency (ANUE), and grain yield of rice cultivars under the salinity stress were improved by the NPK-gypsum and NPK-Zn options relatively to the NPK option, suggesting that NPK-gypsum and NPK-Zn are suitable management options in reducing adverse effect of low K/Na, low ANUE as well as to improve rice yield under salinity stress

Effects of Alternate Wetting and Drying Irrigation Regime and Nitrogen Fertilizer on Yield and Nitrogen Use Efficiency of Irrigated Rice in the Sahel

The objectives of this study were to investigate water saving strategies in the paddy field and to evaluate the performance of some of the newly released rice varieties. Field experiments were conducted at Fanaye in the Senegal River Valley during two rice growing seasons in 2015. Three irrigation regimes ((i) continuous flooding, (ii) trigging irrigation at soil matric potential (SMP) of 30 kPa, (iii) trigging irrigation at SMP of 60 kPa) were tested in an irrigated lowland rice field. Irrigation regimes (ii) and (iii) are alternate wetting and drying (AWD) cycles. Four inbred rice varieties (NERICA S-21, NERICA S-44, Sahel 210 and Sahel 222) and one hybrid rice (Hybrid AR032H) were evaluated under five nitrogen fertilizer rates (0, 50, 100, 150 and 200 kg N ha−1). The results showed that rice yield varied from 0.9 to 12 t ha−1. The maximum yield of 12 t ha−1 was achieved by NERICA S-21 under AWD 30 kPa at 150 kg N ha−1. The AWD irrigation management at 30 kPa resulted in increasing rice yield, rice water use and nitrogen use efficiency and reducing the irrigation applications by 27.3% in comparison with continuous flooding. AWD30 kPa could be adopted as a water saving technology for water productivity under paddy production in the Senegal River Middle Valley. Additional research should be conducted in the upper Valley, where soils are sandier and water is less available, for the sustainability and the adoption of the irrigation water saving practices across the entire Senegal River Valley

Refurbishment of public housing villas in the United Arab Emirates (UAE): energy and economic impact

© 2016, Springer Science+Business Media Dordrecht. This study aims at assessing the technical and economic benefits of refurbishing existing public housing villas in the UAE. Four representative federal public housing villas built between 1980s and 2010s were modeled and analyzed. The Integrated Environmental Solutions-Virtual Environment (IES-VE) energy modeling software was used to estimate the energy consumption and savings due to different refurbishment configurations applied to the villas. The refurbishment technical configurations were based on the UAE’s Estidama green buildings sustainability assessment system. The refurbishment configurations include upgrading three elements: the wall and roof insulation as well as replacing the glazing. The annual electricity savings results indicated that the most cost-efficient refurbishment strategy is upgrading of wall insulation (savings up to 20.8 %) followed by upgrading the roof’s insulation (savings up to 11.6 %) and lastly replacing the glazing (savings up to 3.2 %). When all three elements were refurbished simultaneously, savings up to 36.7 % were achieved (villa model 670). The savings translated to CO2 emission reduction of 22.6 t/year. The simple and discounted payback periods for the different configurations tested ranged between 8 and 28 and 10 and 50 years, respectively

Pembrolizumab plus enzalutamide and androgen deprivation therapy versus placebo plus enzalutamide and androgen deprivation therapy for metastatic hormone-sensitive prostate cancer: the randomized, double-blind, phase III KEYNOTE-991 study

Background: Despite treatment advances, most patients with metastatic hormone-sensitive prostate cancer (mHSPC) experience disease progression to castration-resistant disease within 5 years. The placebo-controlled, double-blind, phase III KEYNOTE-991 study evaluated the efficacy and safety of adding pembrolizumab to enzalutamide and androgen deprivation therapy (ADT) in participants with mHSPC. Patients and methods: Eligible participants were aged > >18 years with next-generation hormonal agent-naive mHSPC. Participants were randomly assigned (1 : 1) to receive intravenous pembrolizumab 200 mg or placebo every 3 weeks for >3 adverse events (AEs) and serious AEs (SAEs) were reported in 61.9% versus 38.1% and 40.3% versus 23.2% of participants in the pembrolizumab versus the placebo arm, respectively. Any-grade rash occurred at a higher frequency with pembrolizumab (25.1%) versus placebo (9.3%). Conclusions: KEYNOTE-991 did not meet its primary endpoint and was stopped for futility. The addition of pembrolizumab to enzalutamide and ADT was associated with higher frequencies of grade > >3 AEs and SAEs than with placebo. Rash was identified as an additional safety signal with pembrolizumab plus enzalutamide and ADT

Health-seeking behaviour and beliefs around sore throat in The Gambia: A qualitative study.

Group A Streptococcus (Strep A) bacteria causes a broad spectrum of diseases. The most common manifestations of Strep A infection are sore throat and pus-producing skin infections such as impetigo. Complications of Strep A infection can lead to inflammation in the bones, muscles, joints, and internal organs causing acute rheumatic fever and rheumatic heart disease (RHD). In The Gambia, the RHD burden is thought to be very high. However, epidemiological data is minimal, and Strep A control programmes do not exist. This study aimed to explore common beliefs and practices related to sore throats among primary caregivers of children, and healthcare providers in a community with a high Strep A disease burden. Four informal conversations with providers and fifteen semi-structured interviews with caregivers were conducted in the peri-urban area of Sukuta, The Gambia. Sampling was purposive and gradual, beginning from households identified to have recently experienced sore throat through a parallel cohort study. Themes explored in qualitative analysis included: sore throat causal attributions and diagnoses, care practises, health-seeking behaviour, and perceived barriers to using the biomedical sector. We found that sore throats were typically perceived to affect one child in a family, disproportionately or exclusively. Sore throats were rarely perceived as life-threatening, and awareness of links between sore throat and ARF or RHD was not reported among caregivers or providers in this study population. Most cases of sore throat were initially managed at home using traditional medicine which delayed resort to antibiotics, though in two instances of severe pain with the presence of exudate, fear that the child's life was at risk prompted care-seeking through the formal health system. Our findings can inform the development of tailored strategies to increase community knowledge of the potential long-term consequences of sore throats and appropriate care-seeking, alongside improvements in the health system, to prevent Strep A sequelae effectively