Repetitions in the polypeptide sequence of cytochromes

Protein evolution from peptides, gene duplications and deletions in polypeptides and cytochrome

Deworming and Development: Asking the Right Questions, Asking the Questions Right

Two billion people are infected with intestinal worms. In many areas, the majority of schoolchildren are infected, and the World Health Organization (WHO) has called for school-based mass deworming. The key area for debate is not whether deworming medicine works—in fact, the medical literature finds that treatment is highly effective, and thus the standard of care calls for treating any patient known to harbor an infection. As the authors of the Cochrane systematic review point out, a critical issue in evaluating current soil-transmitted helminth policies is whether the benefits of deworming exceed the costs or whether it would be more prudent to use the money for other purposes. While in general we think the Cochrane approach is very valuable, we argue below that many of the underlying studies of deworming suffer from three critical methodological problems: treatment externalities in dynamic infection systems, inadequate measurement of cognitive outcomes and school attendance, and sample attrition. We then argue that the currently available evidence from studies that address these issues is consistent with the consensus view expressed by other reviews and by policymakers that deworming is a very cost-effective way to increase school participation and has a high benefit to cost ratio.Economic

Transient subglacial water routing efficiency modulates ice velocities prior to surge termination on Sít’ Kusá, AK

publishedVersio

Propagating speedups during quiescence escalate to the 2020-2021 surge of Sít' Kusá, southeast Alaska

publishedVersio

Active flow control systems architectures for civil transport aircraft

Copyright @ 2010 American Institute of Aeronautics and AstronauticsThis paper considers the effect of choice of actuator technology and associated power systems architecture on the mass cost and power consumption of implementing active flow control systems on civil transport aircraft. The research method is based on the use of a mass model that includes a mass due to systems hardware and a mass due to the system energy usage. An Airbus A320 aircraft wing is used as a case-study application. The mass model parameters are based on first-principle physical analysis of electric and pneumatic power systems combined with empirical data on system hardware from existing equipment suppliers. Flow control methods include direct fluidic, electromechanical-fluidic, and electrofluidic actuator technologies. The mass cost of electrical power distribution is shown to be considerably less than that for pneumatic systems; however, this advantage is reduced by the requirement for relatively heavy electrical power management and conversion systems. A tradeoff exists between system power efficiency and the system hardware mass required to achieve this efficiency. For short-duration operation the flow control solution is driven toward lighter but less power-efficient systems, whereas for long-duration operation there is benefit in considering heavier but more efficient systems. It is estimated that a practical electromechanical-fluidic system for flow separation control may have a mass up to 40% of the slat mass for a leading-edge application and 5% of flap mass for a trailing-edge application.This work is funded by the Sixth European Union Framework Programme as part of the AVERT project (Contract No. AST5-CT-2006-030914

Reading and Phonological Awareness in Africa

Literacy levels in Africa are low, and school instruction outcomes are not promising. Africa also has a disproportionate number of unschooled children. Phonological awareness (PA), especially phoneme awareness, is critically associated with literacy, but there is little evidence about whether PA is gained through literacy, schooling, or both, because most children studied are in education and can read at least letters. Our previous study of PA and reading in children in and out of school in Tanzania found that PA was associated with reading ability, not schooling or age, and many unschooled children learned to read. We retested 85 children from the baseline study, on measures of PA and literacy, approximately 2 years later. We found that more unschooled children had now learned to read but PA had generally not improved for these children. Unschooled children were still poorer at PA than schooled children. At 2 years, schooling now independently predicted PA and literacy. PA also predicted literacy and vice versa. Explicit phoneme awareness was again poor, even in accurate readers. More unschooled children have now learned to read, possibly because local literacy is in their first language; however, schooling improves reading and PA

HIRDLS Science Meeting Oxford (20 Sep 2006) Presentations

Selection of presentations given at the HIRDLS Science Meeting Oxford on the 20th September 2006

Saddle-nodes and period-doublings of smale horseshoes: a case study near resonant homoclinic bellows

Abstract In unfoldings of resonant homoclinic bellows interesting bifurcation phenomena occur: two suspensed Smale horseshoes can collide and disappear in saddle-node bifurcations (all periodic orbits disappear through saddle-node bifurcations, there are no other bifurcations of periodic orbits), or a suspended horseshoe can go through saddle-node and period-doubling bifurcations of the periodic orbits in it to create an additional "doubled horseshoe"