494 research outputs found

    Farmer perceptions of legumes and their functions in smallholder farming systems in east Africa

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    Legumes play an important role in sub-Saharan Africa (SSA) farming systems through the provision of food, feed, fuel, income and a range of biophysical benefits, such as soil fertility enhancement and erosion control. However, their full potential is not being realized. The purpose of this study was to assess farmers’ perceptions and knowledge towards legumes and the rationale of farmers for current legume production practices using a survey of 268 farmers in the Democratic Republic of Congo and Kenya. Most of the farmers had some knowledge of legumes and their characteristics. However, they had little knowledge of some key functions, including soil erosion control and soil fertility improvement. Most farmers relied on radio and other farmers for legume-related information. Farmers with relatively large livestock holdings ranked provision of livestock feed as an important legume function. We conclude that farmers put more value on short-term benefits of legumes including food and income than long-term benefits such as natural resource management and thus grain legumes are more readily identified by farmers than forage species. Also, we conclude that farmers require more than just information about legumes to increase uptake, they also require improved market access to procure inputs and sell products to realize other benefits that are associated with growing legumes

    Uniqueness in MHD in divergence form: right nullvectors and well-posedness

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    Magnetohydrodynamics in divergence form describes a hyperbolic system of covariant and constraint-free equations. It comprises a linear combination of an algebraic constraint and Faraday's equations. Here, we study the problem of well-posedness, and identify a preferred linear combination in this divergence formulation. The limit of weak magnetic fields shows the slow magnetosonic and Alfven waves to bifurcate from the contact discontinuity (entropy waves), while the fast magnetosonic wave is a regular perturbation of the hydrodynamical sound speed. These results are further reported as a starting point for characteristic based shock capturing schemes for simulations with ultra-relativistic shocks in magnetized relativistic fluids.Comment: To appear in J Math Phy

    Atrial secondary tricuspid regurgitation: pathophysiology, definition, diagnosis, and treatment.

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    Atrial secondary tricuspid regurgitation (A-STR) is a distinct phenotype of secondary tricuspid regurgitation with predominant dilation of the right atrium and normal right and left ventricular function. Atrial secondary tricuspid regurgitation occurs most commonly in elderly women with atrial fibrillation and in heart failure with preserved ejection fraction in sinus rhythm. In A-STR, the main mechanism of leaflet malcoaptation is related to the presence of a significant dilation of the tricuspid annulus secondary to right atrial enlargement. In addition, there is an insufficient adaptive growth of tricuspid valve leaflets that become unable to cover the enlarged annular area. As opposed to the ventricular phenotype, in A-STR, the tricuspid valve leaflet tethering is typically trivial. The A-STR phenotype accounts for 10%-15% of clinically relevant tricuspid regurgitation and has better outcomes compared with the more prevalent ventricular phenotype. Recent data suggest that patients with A-STR may benefit from more aggressive rhythm control and timely valve interventions. However, little is mentioned in current guidelines on how to identify, evaluate, and manage these patients due to the lack of consistent evidence and variable definitions of this entity in recent investigations. This interdisciplinary expert opinion document focusing on A-STR is intended to help physicians understand this complex and rapidly evolving topic by reviewing its distinct pathophysiology, diagnosis, and multi-modality imaging characteristics. It first defines A-STR by proposing specific quantitative criteria for defining the atrial phenotype and for discriminating it from the ventricular phenotype, in order to facilitate standardization and consistency in research

    Calibration of GENEActiv accelerometer wrist cut-points for the assessment of physical activity intensity of pre-school aged children

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    This study sought to validate cut-points for use of wrist worn GENEActiv accelerometer data, to analyse preschool children’s (4 to 5 year olds) physical activity (PA) levels via calibration with oxygen consumption values (VO2). This was a laboratory based calibration study. Twenty-one preschool children, aged 4.7 ± 0.5 years old, completed six activities (ranging from lying supine to running) whilst wearing the GENEActiv accelerometers at two locations (left and right wrist), these being the participants’ non-dominant and dominant wrist, and a Cortex face mask for gas analysis. VO2 data was used for the assessment of criterion validity. Location specific activity intensity cut points were established via Receiver Operator Characteristic curve (ROC) analysis. The GENEActiv accelerometers, irrespective of their location, accurately discriminated between all PA intensities (sedentary, light, and moderate and above), with the dominant wrist monitor providing a slightly more precise discrimination at light PA and the non-dominant at the sedentary behaviour and moderate and above intensity levels (Area Under the Curve (AUC) for non-dominant = 0.749-0.993, compared to AUC dominant = 0.760-0.988). Conclusion: This study establishes wrist-worn physical activity cut points for the GENEActiv accelerometer in pre-schoolers.N/

    Total fluid intake and the risk of recurrence in patients with non-muscle invasive bladder cancer::a prospective cohort study

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    Objectives: To investigate the role of fluid intake from beverages before and after a diagnosis of bladder cancer in relation to the risk of developing bladder cancer recurrence. Study Design: Prospective cohort study. Methods: 716 patients with non-muscle invasive bladder cancer (NMIBC), who received transurethral resection of a primary bladder tumour (TURBT) and completed self-administrated questionnaires on usual fluid intake from beverages at time of diagnosis (over the year before diagnosis) and during follow-up (over the year after diagnosis), were included. Multivariable Cox regression was used to calculate hazard ratios and 95% confidence intervals of developing recurrent bladder cancer in relation to the intake of total fluid, total alcohol, and individual beverages. Results: During 2,025 person-years of follow-up, 238 (33%) of the included 716 NMIBC patients developed one or more recurrences of bladder cancer. Total fluid intake before diagnosis was not associated with a first recurrence of bladder cancer when comparing the highest and lowest intake group (HR = 0.98, 95% C.I. 0.70-1.38, p = 0.91). Comparable results were obtained for total fluid intake pre-diagnosis and the risk of developing multiple recurrences of bladder cancer (HR = 1.01, 95% C. I. 0.87-1.19, p = 0.85). A total of 379 of the 716 patients reported on usual fluid intake within 1 year of diagnosis. No significant associations between total fluid intake 1 year after diagnosis and a first recurrence of bladder cancer were found when comparing the highest and lowest intake group (HR = 0.91; 95% C. I. 0.60-1.37, p = 0.65) or with multiple recurrences of bladder cancer (HR = 1.06; 95% C. I. 0.89-1.26, p = 0.54). In addition, total alcohol intake and individual beverages were not associated with bladder cancer recurrence. Conclusions: The results indicate that an individual's fluid intake from beverages is unlikely to have an important role in bladder cancer recurrence

    Diet rapidly and reproducibly alters the human gut microbiome

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    Long-term diet influences the structure and activity of the trillions of microorganisms residing in the human gut1–5, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here, we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila, and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale, and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals2, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi, and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids, and the outgrowth of microorganisms capable of triggering inflammatory bowel disease6. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles

    Controlling the 3D architecture of Self-Lifting Auto-generated Tissue Equivalents (SLATEs) for optimized corneal graft composition and stability

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    Ideally, biomaterials designed to play specific physical and physiological roles in vivo should comprise components and microarchitectures analogous to those of the native tissues they intend to replace. For that, implantable biomaterials need to be carefully designed to have the correct structural and compositional properties, which consequently impart their bio-function. In this study, we showed that the control of such properties can be defined from the bottom-up, using smart surface templates to modulate the structure, composition, and bio-mechanics of human transplantable tissues. Using multi-functional peptide amphiphile-coated surfaces with different anisotropies, we were able to control the phenotype of corneal stromal cells and instruct them to fabricate self-lifting tissues that closely emulated the native stromal lamellae of the human cornea. The type and arrangement of the extracellular matrix comprising these corneal stromal Self-Lifting Analogous Tissue Equivalents (SLATEs) were then evaluated in detail, and was shown to correlate with tissue function. Specifically, SLATEs comprising aligned collagen fibrils were shown to be significantly thicker, denser, and more resistant to proteolytic degradation compared to SLATEs formed with randomly-oriented constituents. In addition, SLATEs were highly transparent while providing increased absorption to near-UV radiation. Importantly, corneal stromal SLATEs were capable of constituting tissues with a higher-order complexity, either by creating thicker tissues through stacking or by serving as substrate to support a fully-differentiated, stratified corneal epithelium. SLATEs were also deemed safe as implants in a rabbit corneal model, being capable of integrating with the surrounding host tissue without provoking inflammation, neo-vascularization, or any other signs of rejection after a 9-months follow-up. This work thus paves the way for the de novo biofabrication of easy-retrievable, scaffold-free human tissues with controlled structural, compositional, and functional properties to replace corneal, as well as other, tissuesThis study was supported by the Medical Research Council grant MR/ K017217/1, the Biotechnology and Biological Sciences Research Council, grant BB/I008187/1 and the Spanish Plan Nacional de InvestigaciĂłn CientĂ­fica, Desarrollo e InnovaciĂłn TecnolĂłgica (I + D + I) from the Spanish Ministry of Economy and Competitiveness (Instituto de Salud Carlos III), grant FIS PI14/0955 (cofinanced by FEDER funds, European Union)
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