298 research outputs found
Trade-offs between biomass use and soil cover. The case of rice-based cropping systems in the lake Alaotra region of Madagascar
Farmers in the Lake Alaotra region of Madagascar are currently evaluating a range of conservation agriculture (CA) cropping systems. Most of the expected agroecological functions of CA (weed control, erosion control and water retention) are related to the degree of soil cover. Under farmersâ conditions, the grain and biomass productivity of these systems is highly variable and the biomass is used for several purposes. In this study, we measured biomass production of cover crops and crops in farmersâ fields. Further, we derived relationships to predict the soil cover that can be generated for a particular quantity of mulch. We used these relationships to explore the variability of soil cover that can be generated in farmersâ fields, and to estimate howmuch of the biomass can be removed for use as livestock feed, while retaining sufficient soil cover. Three different kinds of cropping systems were investigated in 91 farmersâ fields. The first two cropping sequences were on the hillsides: (i) maize + pulse (Vigna unguiculata or Dolichos lablab) in year 1, followed by upland rice in year 2; (ii) the second crop sequence included several years of Stylosanthes guianensis followed by upland rice; (iii) the third crop sequence was in lowland paddy fields: Vicia villosa or D. lablab, which was followed by rice within the same year and repeated every year. The biomass available prior to rice sowing varied from 3.6 t ha-1 with S. guianensis to 7.3 t ha-1 with V. villosa. The relationship between the mulch quantity (M) and soil cover (C) was measured using digital imaging and was well described by the following equation: C = 1 - exp(-Am Ă M), where Am is an area-to-mass ratio with R2 > 0.99 in all cases. The calculated average soil cover varied from 56 to 97% for maize + V. unguiculata and V. villosa, respectively. In order to maintain 90% soil cover at rice sowing, the average amount of biomass of V. villosa that could be removed was at least 3 t ha-1 for three quarters of the fields. This quantity was less for other annual or biennial cropping systems. On average the V. villosa aboveground biomass contained 236 kg N ha-1. The study showed that for the conditions of farmers of Malagasy, the production and conservation of biomass is not always sufficient to fulfil all the above-cited agroecological functions of mulch. Inventory of the soil cover capacity for different types of mulch may help farmers to decide how much biomass they can remove from the fiel
Limits of conservation agriculture to overcome low crop yields in sub-Saharan Africa
Conservation agriculture (CA) has become a dominant paradigm in scientific and policy thinking about the sustainable intensification
of food production in sub-Saharan Africa. Yet claims that CA leads to increasing crop yields in African smallholder
farming systems remain controversial. Through a meta-analysis of 933 observations from 16 different countries in sub-Saharan African studies, we show that average yields under CA are only slightly higher than those of conventional tillage systems (3.7% for six major crop species and 4.0% for maize). Larger yield responses for maize result from mulching and crop rotations/intercropping. When CA principles are implemented concomitantly, maize yield increases by 8.4%. The largest yield benefits from CA occur in combination with low rainfall and herbicides. We conclude that although CA may bring soil conservation benefits, it is not a technology for African smallholder farmers to overcome low crop productivity and food insecurity in the short term
Outcome of Endometrial Cancer Stage IIIA with Adnexa or Serosal Involvement Only
Objective. The aim of this study is to look at possible differences in outcome between serosa and adnexal involvement stage IIIA endometrial carcinoma.
Methods. 67 patients with stage IIIA endometrial carcinoma were included, 46 with adnexal involvement and 21 with serosa. A central histopathological review was performed. Results. The 7-year locoregional failure rate was (LRFR) 2.2% for adnexal involvement and 16.0% for involvement of the serosa (P = .0522). The 7-year distant metastasis-free survival was 72.7% for adnexal involvement and 58.7% for serosa (P = .3994). The 7-year disease-specific survival (DSS) was 71.8% for patients with adnexal involvement and 75.4% for patients with serosa. Conclusion. Endometrial carcinoma stage IIIA with involvement of the adnexa or serosa showed to have a comparable disease-specific survival. Locoregional control was worse for serosa involvement compared to adnexa
Peaâwheat intercrops in low-input conditions combine high economic performances and low environmental impacts
Intensive agriculture ensures high yields but can cause serious environmental damages. The optimal use of soil and atmospheric sources of nitrogen in cerealâlegume mixtures may allow farmers to maintain high production levels and good quality with low external N inputs, and could potentially decrease environmental impacts, particularly through a more efficient energy use. These potential advantages are presented in an overall assessment of cerealâlegume systems, accounting for the agronomic, environmental, energetic, and economic performances. Based on a low-input experimental field network including 16 site-years, we found that yields of peaâwheat intercrops (about 4.5 Mg haâ1 whatever the amount of applied fertiliser) were higher than sole pea and close to conventionally managed wheat yields (5.4 Mg haâ1 on average), the intercrop requiring less than half of the nitrogen fertiliser per ton of grain compared to the sole wheat. The land equivalent ratio and a statistical analysis based on the Price\u27s equation showed that the crop mixture was more efficient than sole crops particularly under unfertilised situations. The estimated amount of energy consumed per ton of harvested grains was two to three times higher with conventionally managed wheat than with peaâwheat mixtures (fertilised or not). The intercrops allowed (i) maintaining wheat grain protein concentration and gross margin compared to wheat sole crop and (ii) increased the contribution of N2 fixation to total N accumulation of pea crop in the mixture compared to pea sole crop. They also led to a reduction of (i) pesticide use compared to sole crops and (ii) soil mineral nitrogen after harvest compared to pea sole crop. Our results demonstrate that peaâwheat intercropping is a promising way to produce cereal grains in an efficient, economically sustainable and environmentally friendly way
Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage
We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe2O3) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the âpureâ conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt4BF4 (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of chargeâdischarge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertionâexpulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during chargeâdischarge processes
Desempenho agronÎmico de mandioca de mesa manejada com irrigação e uso de cobertura plåstica do solo.
Resumo Apesar da mandioca ser reconhecida pela sua elevada tolerĂąncia Ă seca, a irrigação vem apresentando resultados satisfatĂłrios. Entretanto, poucos estudos vĂȘm sendo desenvolvidos visando a determinação dos efeitos da cobertura do solo, da irrigação e da combinação de ambos no desenvolvimento da cultura. O objetivo deste estudo foi determinar a influĂȘncia da irrigação e da cobertura plĂĄstica do solo, no desempenho agronĂŽmico de mandioca de mesa. O plantio foi feito em canteiros, no sistema de fileira dupla com as manivas-sementes implantadas na vertical em espaçamento de 0,60 m entre linhas e 0,80 m entre plantas. Foram aplicados os tratamentos canteiro desnudo sem irrigação, canteiro coberto com plĂĄstico de polietileno preto sem irrigação, canteiro desnudo com irrigação e canteiro coberto com plĂĄstico de polietileno preto com irrigação. As irrigaçÔes foram por aspersĂŁo convencional, com base no balanço diĂĄrio de ĂĄgua do solo na profundidade efetiva do sistema radicular da mandioca nos diferentes estĂĄgios de desenvolvimento da cultura. Os caracteres avaliados em duas safras foram: produtividade de parte aĂ©rea, produtividade de raĂzes, porcentagem de amido nas raĂzes e tempo para a cocção. A expressĂŁo dos caracteres produtividade de raĂzes, peso da parte aĂ©rea e teor de amido nas raĂzes, foi influenciada pelo manejo da irrigação e pela cobertura do solo. A utilização individual das tecnologias de irrigação e de cobertura plĂĄstica do solo, proporcionaram aumentos de produtividade de raĂzes de 55% e 13%, respectivamente, e quando foram utilizadas em conjunto a produtividade de raĂzes aumentou 89%
Association between anthropometry and lifestyle factors and risk of B cell lymphoma: an exposome wide analysis.
To better understand the role of individual and lifestyle factors in human disease, an exposome-wide association study was performed to investigate within a single study anthropometry measures and lifestyle factors previously associated with B-cell lymphoma (BCL). Within the European Prospective Investigation into Cancer and nutrition study, 2,402 incident BCL cases were diagnosed from 475,426 participants that were followed-up on average 14âyears. Standard and penalized Cox regression models as well as principal component (PC) analysis were used to evaluate 84 exposures in relation to BCL risk. Standard and penalized Cox regression models showed a positive association between anthropometric measures and BCL and multiple myeloma/plasma cell neoplasm (MM). The penalized Cox models additionally showed the association between several exposures from categories of physical activity, smoking status, medical history, socioeconomic position, and diet and BCL and/or the subtypes. PC analyses confirmed the individual associations but also showed additional observations. The PC5 including anthropometry, was positively associated with BCL, diffuse large B-cell lymphoma (DLBCL), and MM. There was a significant positive association between consumption of sugar and confectionary (PC11) and follicular lymphoma risk, and an inverse association between fish and shellfish and Vitamin D (PC15) and DLBCL risk. The PC1 including features of the Mediterranean diet and diet with lower inflammatory score showed an inverse association with BCL risk, while the PC7, including dairy, was positively associated with BCL and DLBCL risk. Physical activity (PC10) was positively associated with DLBCL risk among women. This study provided informative insights on the etiology of BCL
Human Cysteine Cathepsins Are Not Reliable Markers of Infection by Pseudomonas aeruginosa in Cystic Fibrosis
Cysteine cathepsins have emerged as new players in inflammatory lung disorders. Their activities are dramatically increased in the sputum of cystic fibrosis (CF) patients, suggesting that they are involved in the pathophysiology of CF. We have characterized the cathepsins in CF expectorations and evaluated their use as markers of colonization by Pseudomonas aeruginosa. The concentrations of active cathepsins B, H, K, L and S were the same in P. aeruginosa-positive (19 Ps+) and P. aeruginosa-negative (6 Psâ) samples, unlike those of human neutrophil elastase. Also the cathepsin inhibitory potential and the cathepsins/cathepsin inhibitors imbalance remained unchanged and similar (âŒ2-fold) in the Ps+ and Psâ groups (p<0.001), which correlated with the breakdown of their circulating cystatin-like inhibitors (kininogens). Procathepsins, which may be activated autocatalytically, are a potential proteolytic reservoir. Immunoblotting and active-site labeling identified the double-chain cathepsin B, the major cathepsin in CF sputum, as the main molecular form in both Ps+ and Psâ samples, despite the possible release of the âŒ31 kDa single-chain form from procathepsin B by sputum elastase. Thus, the hydrolytic activity of cysteine cathepsins was not correlated with bacterial colonization, indicating that cathepsins, unlike human neutrophil elastase, are not suitable markers of P. aeruginosa infection
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