223 research outputs found
Responding to the crisis in sub-Saharan Africa: The role of nutrition
In the chapter dealing with education and health, the report of the influential
Commission for Africa prioritises basic health systems, HIV/AIDS, malaria and
tuberculosis. In contrast, nutrition is given less than half a page and is reduced to
parasite control and micronutrient support. Such neglect of nutrition is hard to
understand in the context of increasing hunger and malnutrition across the continent.
Sub-Saharan Africa is the only region in the world where the proportion of
underweight children has stagnated and the absolute numbers have actually
increased in the last decade. It has been pointed out that if current trends continue
sub-Saharan Africa will achieve the Millennium Development Goal for child mortality
around 2115 – one century after the target date. Quite clearly those concerned with
nutrition need to more powerfully advocate the role of nutrition in lifting Africa out of
the spiral of poverty. The present paper argues that to achieve this requires an
understanding not just of the critical role of nutrition for health and development
(both individual and national), but also of how recent global changes are interacting
with changes in food production and supply, other determinants of maternal and
child health, and the role and capacity of the state to tackle malnutrition in Africa. It
concludes by suggesting some responses that nutritionists could now be making
STEER: Beam Selection for Full-Duplex Millimeter Wave Communication Systems
Modern millimeter wave (mmWave) communication systems rely on beam alignment
to deliver sufficient beamforming gain to close the link between devices. We
present a novel beam selection methodology for multi-panel, full-duplex mmWave
systems, which we call STEER, that delivers high beamforming gain while
significantly reducing the full-duplex self-interference coupled between the
transmit and receive beams. STEER does not necessitate changes to conventional
beam alignment methodologies nor additional over-the-air feedback, making it
compatible with existing cellular standards. Instead, STEER uses conventional
beam alignment to identify the general directions beams should be steered, and
then it makes use of a minimal number of self-interference measurements to
jointly select transmit and receive beams that deliver high gain in these
directions while coupling low self-interference. We implement STEER on an
industry-grade 28 GHz phased array platform and use further simulation to show
that full-duplex operation with beams selected by STEER can notably outperform
both half-duplex and full-duplex operation with beams chosen via conventional
beam selection. For instance, STEER can reliably reduce self-interference by
more than 20 dB and improve SINR by more than 10 dB, compared to conventional
beam selection. Our experimental results highlight that beam alignment can be
used not only to deliver high beamforming gain in full-duplex mmWave systems
but also to mitigate self-interference to levels near or below the noise floor,
rendering additional self-interference cancellation unnecessary with STEER
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Polaron spin dynamics in high-mobility polymeric semiconductors
Polymeric semiconductors exhibit exceptionally long spin lifetimes, and recently observed micrometre spin diffusion lengths in conjugated polymers demonstrate the potential for organic spintronics devices. Weak spin–orbit and hyperfine interactions lie at the origin of their long spin lifetimes, but the coupling mechanism of a spin to its environment remains elusive. Here, we present a systematic study of polaron spin lifetimes in field-effect transistors with high-mobility conjugated polymers as an active layer. We demonstrate how spin relaxation is governed by the charges’ hopping motion at low temperatures, whereas an Elliott–Yafet-like relaxation due to a transient localization of the carrier wavefunctions is responsible for spin relaxation at high temperatures. In this regime, charge, spin and structural dynamics are intimately related and depend sensitively on the local conformation of polymer backbones and the crystalline packing of the polymer chains.* ERC Synergy grant SC2 (no. 610115)
* Alexander von Humboldt Foundation
* Transregional Collaborative Research Center (SFB/TRR) 173 SPIN+X
* Winton Programme for the Physics of Sustainability
* Engineering and Physical Sciences Research Council (EPSRC)
* Excellence Initiative by the Graduate School Materials Science in Mainz (GSC 266)
* European Commission/Région Wallonne (FEDER–BIORGEL project), the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds National de la Recherche Scientifique (FRS-FNRS) under grant no. 2.5020.11 * Tier-1 supercomputer of the Fédération Wallonie-Bruxelles, infrastructure funded by the Walloon Region under grant agreement n111754
Financial considerations in the conduct of multi-centre randomised controlled trials: evidence from a qualitative study.
National Coordinating Centre for Research Methodology; Medical Research Council, UK Department of Health; Chief Scientist OfficeNot peer reviewedPublisher PD
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Sorghum Genome Sequencing by Methylation Filtration
Sorghum bicolor is a close relative of maize and is a staple crop in Africa and much of the developing world because of its superior tolerance of arid growth conditions. We have generated sequence from the hypomethylated portion of the sorghum genome by applying methylation filtration (MF) technology. The evidence suggests that 96% of the genes have been sequence tagged, with an average coverage of 65% across their length. Remarkably, this level of gene discovery was accomplished after generating a raw coverage of less than 300 megabases of the 735-megabase genome. MF preferentially captures exons and introns, promoters, microRNAs, and simple sequence repeats, and minimizes interspersed repeats, thus providing a robust view of the functional parts of the genome. The sorghum MF sequence set is beneficial to research on sorghum and is also a powerful resource for comparative genomics among the grasses and across the entire plant kingdom. Thousands of hypothetical gene predictions in rice and Arabidopsis are supported by the sorghum dataset, and genomic similarities highlight evolutionarily conserved regions that will lead to a better understanding of rice and Arabidopsis
Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020
Background: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity <6/18, ≥3/60) and blindness (presenting visual acuity <3/60). Estimates are age-standardized using the GBD standard population. Results: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by −27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). Conclusions: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.</p
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