41,931 research outputs found
Genetic Engineering for the Poor: Golden Rice and Public Health in India
No full textVitamin A deficiency (VAD) affects millions of people, causing serious health problems. Golden Rice (GR), which has been genetically engineered to produce β-carotene, is being proposed as a remedy. While this new technology has aroused controversial debates, its actual impact remains unclear. We develop a methodology for ex ante evaluation, taking into account health and nutrition details, as well as socioeconomic and policy factors. The framework is used for empirical analyses in India. Given broad public support, GR could more than halve the disease burden of VAD. Juxtaposing health benefits and overall costs suggests that GR could be very cost-effective
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Comparison of weight-for-height and BMI-for-age for estimating overnutrition burden in under-five population with high stunting prevalence
No full textBackground: Overnourished under-five children are anthropometrically classified as either being at possible risk of overweight, overweight or obese and defined so, when either weight-for-height or Body-Mass-Index-for-age (BMI-for-age) are >1SD to 2SD, >2SD to 3SD and >3SD, respectively of the analogous World Health Organization standards. Aim: To compare weight-for-height and BMI-for-age definitions for quantifying overnutrition burden. Methods: Theoretical consequences of ignoring age were evaluated by comparing, at varying height-for-age zscores, the age- and sex-specific cut-offs of BMI that would define overnutrition with these two metrics. Overnutrition prevalence was then compared in simulated populations (short, intermediate and tall) and real-life datasets from India. Results: In short (-2SD) children, the BMI cut-offs with weight-for-height criteria were lower in comparison to BMI-for-age till 7-8 months, but higher at later ages. In National Family Health Survey-4, India dataset (short population), overnutrition (>1SD) prevalence with weight-for-height was higher from 0-0.5 years (exclusive breastfeeding age), but lower at subsequent ages. The prevalence difference (weight-for-height - BMI-for-age) in 0.5-5 years was -2.26% (6.57% vs 8.83%); this attenuated in 0-5 years (-1.55%; 7.23% vs 8.78%). The discrepancy was maximal for stunted children and was lower in girls. A similar pattern, of lower magnitude, was observed for overweight (>2SD) comparison. In intermediate and tall populations, there were no meaningful differences. Conclusion: The two definitions produce cut-offs, and hence estimates of overnutrition, that differ with the age, sex, and height of under-five children. The relative invariance, with age and height, of BMI-for-age, favours its use
Intergenerational change in anthropometric indices and their predictors among children in New Delhi Birth Cohort
No full textObjective: to evaluate intergenerational change in anthropometric indices of children and their predictors.Design: prospective cohortParticipants: New Delhi Birth Cohort participants (F1), born between 1969 and 1972, were followed-up for anthropometry at birth and 6-monthly intervals until 21 years. Their children (F2) below 10 years were evaluated anthropometrically.Outcome measure: intergenerational change (F2-F1) in height, weight and body mass index (BMI) of children in comparison to their parents at corresponding ages.Results: 432 F2-F1 pairs were analyzed in age-groups of 0-5 (26.9%) and 5-10 (73.1%) years. Children were considerably taller (0-5 years 0.99 SD; 5-10 years 1.17 SD) and heavier (0-5 years 0.77 SD; 5-10 years 1.52 SD) while only those aged 5-10 years were broader (had a higher BMI; 1.03 SD), than their parents. These increases for 0-5 and 5-10 years, respectively corresponded to 3.9 and 6.4 cm for height, 1.3 and 5.4 kg for weight and 0.2 and 1.9 kg/m2 for BMI. Lower parents’ anthropometric indices and poor water supply and sanitation facilities; higher age of parents at child birth and of children when measured (for height and weight); and more parental education (for weight and BMI), were associated with greater intergenerational gains in children.Conclusion: over one generation in an urban middle-class population, whose general living conditions had improved, underfive children have become considerably taller and heavier, and 5- 10 year old children have additionally become broader, than their parents at corresponding ages. Child populations probably ‘grow up’ before ‘growing out’
Efficient p-Multigrid Based Solvers for Isogeometric Analysis on Multipatch Geometries
No full textIsogeometric Analysis can be considered as the natural extension of the Finite Element Method (FEM) to higher-order spline based discretizations simplifying the treatment of complex geometries with curved boundaries. Finding a solution of the resulting linear systems of equations efficiently remains, however, a challenging task. Recently, p-multigrid methods have been considered [18], in which a multigrid hierarchy is constructed based on different approximation orders p instead of mesh widths h as it would be the case in classical h-multigrid schemes [8]. The use of an Incomplete LU-factorization as a smoother within the p-multigrid method has shown to lead to convergence rates independent of both h and p for single patch geometries [19]. In this paper, the focus lies on the application of the aforementioned p-multigrid method on multipatch geometries having a C0-continuous coupling between the patches. The use of ILUT as a smoother within p-multigrid methods leads to convergence rates that are essentially independent of h and p, but depend mildly on the number of patches.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Numerical Analysi
Coronary microvascular dysfunction in male patients with Anderson-Fabry disease and the effect of treatment with alpha galactosidase A
No full textObjective: To measure coronary flow reserve (CFR), an index of microvascular function, in Anderson-Fabry disease (AFD) at baseline and after enzyme replacement therapy (ERT). Methods and results: Mean (SD) myocardial blood flow (MBF) at rest and during hyperaemia ( adenosine 140 mg/kg/min) was measured in 10 male, non-smoking patients (53.8 (10.9) years, cholesterol 5.5 (1.3) mmol/l) and in 24 age matched male, non-smoking controls (52.0 (7.6) years, cholesterol 4.5 (0.6) mmol/l) by positron emission tomography ( PET). Resting and hyperaemic MBF and CFR ( hyperaemic/resting MBF) were reduced in patients compared with controls ( 0.99 (0.17) v 1.17 (0.25) ml/g/ min, p< 0.05; 1.37 (0.32) v 3.44 (0.78) ml/g/ min, p< 0.0001; and 1.41 (0.39) v 3.03 (0.85), p< 0.0001, respectively). This coronary microvascular dysfunction was independent of cholesterol concentrations. PET was repeated in five patients after 10.1 (2.3) months of ERT; resting and hyperaemic MBF and CFR were unchanged after ERT ( 0.99 (0.16) v 0.99 ( 0.16) ml/g/ min; 1.56 (0.29) v 1.71 (0.3) ml/g/ min; and 1.6 (0.37) v 1.74 (0.28), respectively; all not significant). Conclusions: The results of the present study show that patients with AFD have very abnormal coronary microvascular function. These preliminary data suggest that ERT has no effect on coronary microvascular dysfunction. Further work is necessary to determine whether treatment at an earlier stage in the course of the disease may improve coronary microvascular function in patients with AFD
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Novel high performance poly(p-phenylene benzobisimidazole) (PBDI) membranes fabricated by interfacial polymerization for H 2 separation
No full text Membranes with high selectivity and permeance are needed to reduce energy consumption in hydrogen purification and pre-combustion CO 2 capture. Polybenzimidazole (PBI) is one of the leading membrane materials for this separation. In this study, we present superior novel supported PBI (poly(p-phenylene benzobisimidazole), PBDI) membranes prepared by a facile interfacial polymerization (IP) method. The effect of IP reaction duration, operating temperature and pressure on membrane separation performance was systematically investigated. The best performance was achieved for membranes prepared in a 2 h reaction time. The resulting membranes display an ultrahigh mixed-gas H 2 /CO 2 selectivity of 23 at 423 K together with an excellent H 2 permeance of 241 GPU, surpassing the membrane performance of conventional polymers (the 2008 Robeson upper bound). These separation results, together with the facile manufacture, pressure resistance, long-term thermostability (>200 h) and economic analysis, recommend the PBDI membranes for industrial use in H 2 purification and pre-combustion CO 2 capture. Besides, PBDI membranes possess high selectivities towards H 2 /N 2 (up to 60) and H 2 /CH 4 (up to 48) mixtures, indicating their potential applications in ammonia synthesis and syngas production. Accepted Author ManuscriptChemE/Catalysis EngineeringOLD ChemE/Organic Materials and InterfacesRST/Storage of Electrochemical Energ
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