The Icarus Student Satellite - A Fully Autonomous Student Built Small Satellite for NASA

University of Michigan students, with the mentoring support of engineers from NASA, Michigan, and elsewhere, have developed a small endmass satellite—dubbed Icarus—for NASA’s ProSEDS (Propulsive Small Expendable Deployer System) electrodynamic-tether propulsion mission. The ProSEDS experiment will be launched in late 2002 as a secondary payload attached to the second stage of a Delta–II launch vehicle. Following the completion of the Delta–II primary mission, the second stage will initiate a series of burns to place ProSEDS into a 360-km, near-circular orbit at an inclination of 35°. The Icarus endmass satellite will be cast off from the Delta–II second stage and be deployed in the zenith direction. The endmass will remain connected to the Delta–II via a combination space tether consisting of 5-km aluminum conducting tether nearest the Delta–II attached to 10-km nonconducting Spectra fiber, connected to the endmass. Throughout tether deployment, and for the duration of the ProSEDS mission, Icarus will collect and transmit data on tether deployment and dynamics. The endmass is responsible for providing tetherendbody location information (using a GPS receiver) and endbody attitude dynamics (using an aspect magnetometer). The data from these instruments will be stored and transmitted to ground telemetry stations. Power to the endmass will be provided by rechargable batteries and solar cells; an onboard command and data handling system will provide control functions. The endmass will continue to record and transmit data as ProSEDS lowers its altitude. Icarus also serves as a backup for mission location information to the main ProSEDS GPS receiver located on the Delta-II second stage

Surface soft phonon and the root3 x root3 <--> 3 x 3 phase transition in Sn/Ge(111) and Sn/Si(111)

Density Functional Theory (DFT) calculations show that the reversible Sn/Ge(111) $\sqrt{3}\times\sqrt{3} \leftrightarrow 3\times3$ phase transition can be described in terms of a surface soft phonon. The isovalent Sn/Si(111) case does not display this transition since the $\sqrt{3}\times\sqrt{3}$ phase is the stable structure at low temperature, although it presents a partial softening of the $3\times3$ surface phonon. The rather flat energy surfaces for the atomic motion associated with this phonon mode in both cases explain the experimental similarities found at room temperature between these systems. The driving force underlying the $\sqrt{3}\times\sqrt{3} \leftrightarrow 3\times3$ phase transition is shown to be associated with the electronic energy gain due to the Sn dangling bond rehybridization.Comment: 4 pages, Revtex, 4 Encapsulated Postscript figures, uses epsf.sty. Final version published in Phys. Rev. Let

Field Emission Cathodes used in the FEGI Get-Away-Special Shuttle Mission

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76377/1/AIAA-2004-3498-580.pd

A review of prednisolone prescribing for children with acute asthma in the UK

Abstract: Introduction: Worldwide asthma guidelines recommend short courses of oral prednisolone in children with acute exacerbations generating high prescription numbers. There is a paucity of evidence to inform the optimal dose and course duration. This has led to a variation in the recommendations for prednisolone prescribing. Our objective was to assess prednisolone prescribing practise for children with acute asthma in a representative sample of UK prescribers. Methods: We developed an online questionnaire asking prescribers the prednisolone dosage, course duration and formulation used, whether they discussed oral prednisolone side effects with the family and at what child's age they changed from prescribing soluble to non-soluble formulations. This was sent to 1006 UK prescribers including Paediatric Respiratory Consultants, doctors in training, asthma nurses and General Practitioners. Results: 200 complete responses were received (response rate 20%). The majority of surveyed prescribers follow the British National Formulary for Children recommendations on dosage rather than those included in the British Thoracic Society and the Scottish Intercollegiate Guidelines Network. Despite this, we highlighted a 4-fold variation in prednisolone dosages for acute asthma. The majority of prescribers chose 3 days as the course duration. High use of soluble formulations was highlighted. Conclusions: There is wide variation in the dose of prednisolone prescribed for children with acute asthma in the UK. This reflects a relative lack of evidence that needs addressing

Alloparental behaviour and long-term costs of mothers tolerating other members of the group in a plurally breeding mammal

Cooperative-breeding studies tend to focus on a few alloparental behaviours in highly cooperative species exhibiting high reproductive skew and the associated short-term, but less frequently long-term, fitness costs. We analysed a suite of alloparental behaviours (assessed via filming) in a kin-structured, high-density population of plurally breeding European badgers, Meles meles, which are not highly cooperative. Group members, other than mothers, performed alloparental behaviour; however, this was not correlated with their relatedness to within-group young. Furthermore, mothers babysat, allogroomed cubs without reciprocation, and allomarked cubs more than other members of the group (controlling for observation time). For welfare reasons, we could not individually mark cubs; however, the number observed pre-independence never exceeded that trapped. All 24 trapped cubs, in three filmed groups, were assigned both parents using 22 microsatellites. Mothers may breed cooperatively, as the time they babysat their assigned, or a larger, litter size did not differ. Furthermore, two mothers probably allonursed, as they suckled more cubs than their assigned litter size. An 18-year genetic pedigree, however, detected no short-term (litter size; maternal survival to the following year) or long-term (offspring breeding probability; offspring lifetime breeding success) fitness benefits with more within-group mothers or other members of the group. Rather, the number of other members of the group (excluding mothers) correlated negatively with long-term fitness. Mothers may tolerate other members of the group, as nonbreeders undertook more digging. Our study highlights that alloparental care varies on a continuum from that seen in this high-density badger population, where alloparenting behaviour is minimal, through to species where alloparental care is common and provides fitness benefits. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved

Plasmodium falciparum importation does not sustain malaria transmission in a semi-arid region of Kenya

Human movement impacts the spread and transmission of infectious diseases. Recently, a large reservoir of Plasmodium falciparum malaria was identified in a semi-arid region of northwestern Kenya historically considered unsuitable for malaria transmission. Understanding the sources and patterns of transmission attributable to human movement would aid in designing and targeting interventions to decrease the unexpectedly high malaria burden in the region. Toward this goal, polymorphic parasite genes (ama1, csp) in residents and passengers traveling to Central Turkana were genotyped by amplicon deep sequencing. Genotyping and epidemiological data were combined to assess parasite importation. The contribution of travel to malaria transmission was estimated by modelling case reproductive numbers inclusive and exclusive of travelers. P. falciparum was detected in 6.7% (127/1891) of inbound passengers, including new haplotypes which were later detected in locally-transmitted infections. Case reproductive numbers approximated 1 and did not change when travelers were removed from transmission networks, suggesting that transmission is not fueled by travel to the region but locally endemic. Thus, malaria is not only prevalent in Central Turkana but also sustained by local transmission. As such, interrupting importation is unlikely to be an effective malaria control strategy on its own, but targeting interventions locally has the potential to drive down transmission

Joint care can outweigh costs of nonkin competition in communal breeders

Competition between offspring can greatly influence offspring fitness and parental investment decisions, especially in communal breeders where unrelated competitors have less incentive to concede resources. Given the potential for escalated conflict, it remains unclear what mechanisms facilitate the evolution of communal breeding among unrelated females. Resolving this question requires simultaneous consideration of offspring in noncommunal and communal nurseries, but such comparisons are missing. In the Seychelles warbler Acrocephalus sechellensis, we compare nestling pairs from communal nests (2 mothers) and noncommunal nests (1 mother) with singleton nestlings. Our results indicate that increased provisioning rate can act as a mechanism to mitigate the costs of offspring rivalry among nonkin. Increased provisioning in communal broods, as a consequence of having 2 female parents, mitigates any elevated costs of offspring rivalry among nonkin: per-capita provisioning and survival was equal in communal broods and singletons, but lower in noncommunal broods. Individual offspring costs were also more divergent in noncommunal broods, likely because resource limitation exacerbates differences in competitive ability between nestlings. It is typically assumed that offspring rivalry among nonkin will be more costly because offspring are not driven by kin selection to concede resources to their competitors. Our findings are correlational and require further corroboration, but may help explain the evolutionary maintenance of communal breeding by providing a mechanism by which communal breeders can avoid these costs

The Composite Task Reveals Stronger Holistic Processing in Children than Adults for Child Faces

Background: While own-age faces have been reported to be better recognized than other-age faces, the underlying cause of this phenomenon remains unclear. One potential cause is holistic face processing, a special kind of perceptual and cognitive processing reserved for perceiving upright faces. Previous studies have indeed found that adults show stronger holistic processing when looking at adult faces compared to child faces, but whether a similar own-age bias exists in children remains to be shown. Methodology/Principal Findings: Here we used the composite face task – a standard test of holistic face processing – to investigate if, for child faces, holistic processing is stronger for children than adults. Results showed child participants (8–13 years) had a larger composite effect than adult participants (22–65 years). Conclusions/Significance: Our finding suggests that differences in strength of holistic processing may underlie the ownage bias on recognition memory. We discuss the origin of own-age biases in terms of relative experience, face-space tuning, and social categorization

Editorial: Coral Reefs in the Anthropocene – Reflecting on 20 Years of Reef Conservation UK

Editorial on the Research Topic Coral Reefs in the Anthropocene – Reflecting on 20 Years of Reef Conservation UK.N