166 research outputs found
How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRRβs Rehabilitation Engineering Research Centers
Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a βtotal approach to rehabilitationβ, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970βs, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program
Influence of a Dy overlayer on the precessional dynamics of a ferromagnetic thin film
This is the final version of the article. Available from the American Institute of Physics via the DOI in this record.Precessional dynamics of a Co50Fe50(0.7)/Ni 90Fe10(5)/Dy(1)/Ru(3) (thicknesses in nm) thin film have been explored by low temperature time-resolved magneto-optical Kerr effect and phase-resolved x-ray ferromagnetic resonance measurements. As the temperature was decreased from 300 to 140 K, the magnetic damping was found to increase rapidly while the resonance field was strongly reduced. Static x-ray magnetic circular dichroism measurements revealed increasing ferromagnetic order of the Dy moment antiparallel to that of Co50Fe50/Ni 90Fe10. Increased coupling of the Dy orbital moment to the precessing spin magnetization leads to significantly increased damping and gyromagnetic ratio of the film while leaving its magnetic anisotropy effectively unchanged.The authors gratefully acknowledge the financial support of EPSRC Grant EP/F021755/1. The ALS is supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Parts of this work were carried out on beamline 4.0.2 at the ALS and beamline I06-1 at Diamond Light Source
Postcopulatory sexual selection
The female reproductive tract is where competition between the sperm of different males takes place, aided and abetted by the female herself. Intense postcopulatory sexual selection fosters inter-sexual conflict and drives rapid evolutionary change to generate a startling diversity of morphological, behavioural and physiological adaptations. We identify three main issues that should be resolved to advance our understanding of postcopulatory sexual selection. We need to determine the genetic basis of different male fertility traits and female traits that mediate sperm selection; identify the genes or genomic regions that control these traits; and establish the coevolutionary trajectory of sexes
On the diversity of superluminous supernovae: ejected mass as the dominant factor
We assemble a sample of 24 hydrogen-poor superluminous supernovae (SLSNe). Parameterizing the light-curve shape through rise and decline time-scales shows that the two are highly correlated. Magnetar-powered models can reproduce the correlation, with the diversity in rise and decline rates driven by the diffusion time-scale. Circumstellar interaction models can exhibit a similar riseβdecline relation, but only for a narrow range of densities, which may be problematic for these models. We find that SLSNe are approximately 3.5 mag brighter and have light curves three times broader than SNe Ibc, but that the intrinsic shapes are similar. There are a number of SLSNe with particularly broad light curves, possibly indicating two progenitor channels, but statistical tests do not cleanly separate two populations. The general spectral evolution is also presented. Velocities measured from Fe II are similar for SLSNe and SNe Ibc, suggesting that diffusion time differences are dominated by mass or opacity. Flat velocity evolution in most SLSNe suggests a dense shell of ejecta. If opacities in SLSNe are similar to other SNe Ibc, the average ejected mass is higher by a factor 2β3. Assuming ΞΊ = 0.1βcm2βgβ1, we estimate a mean (median) SLSN ejecta mass of 10 Mβ (6 Mβ), with a range of 3β30 Mβ. Doubling the assumed opacity brings the masses closer to normal SNe Ibc, but with a high-mass tail. The most probable mechanism for generating SLSNe seems to be the core collapse of a very massive hydrogen-poor star, forming a millisecond magnetar
Combining dark energy survey science verification data with near-infrared data from the ESO VISTA hemisphere survey
We present the combination of optical data from the Science Verification
phase of the Dark Energy Survey (DES) with near infrared data from the ESO
VISTA Hemisphere Survey (VHS). The deep optical detections from DES are used to
extract fluxes and associated errors from the shallower VHS data. Joint 7-band
() photometric catalogues are produced in a single 3 sq-deg DECam
field centred at 02h26m04d36m where the availability of ancillary
multi-wavelength photometry and spectroscopy allows us to test the data
quality. Dual photometry increases the number of DES galaxies with measured VHS
fluxes by a factor of 4.5 relative to a simple catalogue level matching
and results in a 1.5 mag increase in the 80\% completeness limit of the
NIR data. Almost 70\% of DES sources have useful NIR flux measurements in this
initial catalogue. Photometric redshifts are estimated for a subset of galaxies
with spectroscopic redshifts and initial results, although currently limited by
small number statistics, indicate that the VHS data can help reduce the
photometric redshift scatter at both . We present example
DES+VHS colour selection criteria for high redshift Luminous Red Galaxies
(LRGs) at as well as luminous quasars. Using spectroscopic
observations in this field we show that the additional VHS fluxes enable a
cleaner selection of both populations with 10\% contamination from galactic
stars in the case of spectroscopically confirmed quasars and
contamination from galactic stars in the case of spectroscopically confirmed
LRGs. The combined DES+VHS dataset, which will eventually cover almost 5000
sq-deg, will therefore enable a range of new science and be ideally suited for
target selection for future wide-field spectroscopic surveys.We thank the referee, Nicholas Cross, for a very useful report on
this manuscript. MB acknowledges a postdoctoral fellowship via
OLβs Advanced European Research Council Grant (TESTDE).
Funding for the DES Projects has been provided by the U.S.
Department of Energy, the U.S. National Science Foundation, the
Ministry of Science and Education of Spain, the Science and Technology
Facilities Council of the United Kingdom, the Higher Education
Funding Council for England, the National Center for Supercomputing
Applications at the University of Illinois at Urbana-
Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, Financiadora de Estudos e Projetos, FundacΒΈ Λao
Carlos Chagas Filho de Amparo `a Pesquisa do Estado do Rio de
Janeiro, Conselho Nacional de Desenvolvimento CientΒ΄Δ±fico e Tecnol
Β΄ogico and the MinistΒ΄erio da CiΛencia e Tecnologia, the Deutsche
Forschungsgemeinschaft and the Collaborating Institutions in the
Dark Energy Survey.
The Collaborating Institutions are Argonne National Laboratories,
the University of California at Santa Cruz, the University of
Cambridge, Centro de Investigaciones Energeticas, Medioambientales
y Tecnologicas-Madrid, the University of Chicago, University
College London, the DES-Brazil Consortium, the Eidgen¨ossische
Technische Hochschule (ETH) Z¨urich, Fermi National Accelerator
Laboratory, the University of Edinburgh, the University of
Illinois at Urbana-Champaign, the Institut de Ciencies de lβEspai
(IEEC/CSIC), the Institut de Fisica dβAltes Energies, the Lawrence
Berkeley National Laboratory, the Ludwig-Maximilians Universit
Β¨at and the associated Excellence Cluster Universe, the University
of Michigan, the National Optical Astronomy Observatory,
the University of Nottingham, The Ohio State University, the University
of Pennsylvania, the University of Portsmouth, SLAC National
Laboratory, Stanford University, the University of Sussex,
and Texas A&M University.
The DES participants from Spanish institutions are partially
supported by MINECO under grants AYA2009-13936, AYA2012-
39559, AYA2012-39620, and FPA2012-39684, which include
FEDER funds from the European Union.
We are grateful for the extraordinary contributions of our
CTIO colleagues and the DES Camera, Commissioning and Science
Verification teams in achieving the excellent instrument and
telescope conditions that have made this work possible. The success
of this project also relies critically on the expertise and dedication
of the DES Data Management organisation.
The analysis presented here is based on observations obtained
as part of the VISTA Hemisphere Survey, ESO Progam, 179.A-
2010 (PI: McMahon) and data products from observations made
with ESO Telescopes at the La Silla Paranal Observatory under
programme ID 179.A-2006 (PI: Jarvis).
Data for the OzDES spectroscopic survey were obtained with
the Anglo-Australian Telescope (program numbers 12B/11 and
13B/12). Parts of this research were conducted by the Australian
Research Council Centre of Excellence for All-sky Astrophysics
(CAASTRO), through project number CE110001020. TMD acknowledges
the support of the Australian Research Council through
Future Fellowship, FT100100595.This is the final published version. It first appeared at http://mnras.oxfordjournals.org/content/446/3/2523.abstract
Effects of perceived cocaine availability on subjective and objective responses to the drug
<p>Abstract</p> <p>Rationale</p> <p>Several lines of evidence suggest that cocaine expectancy and craving are two related phenomena. The present study assessed this potential link by contrasting reactions to varying degrees of the drug's perceived availability.</p> <p>Method</p> <p>Non-treatment seeking individuals with cocaine dependence were administered an intravenous bolus of cocaine (0.2 mg/kg) under 100% ('unblinded'; N = 33) and 33% ('blinded'; N = 12) probability conditions for the delivery of drug. Subjective ratings of craving, high, rush and low along with heart rate and blood pressure measurements were collected at baseline and every minute for 20 minutes following the infusions.</p> <p>Results</p> <p>Compared to the 'blinded' subjects, their 'unblinded' counterparts had similar craving scores on a multidimensional assessment several hours before the infusion, but reported higher craving levels on a more proximal evaluation, immediately prior to the receipt of cocaine. Furthermore, the 'unblinded' subjects displayed a more rapid onset of high and rush cocaine responses along with significantly higher cocaine-induced heart rate elevations.</p> <p>Conclusion</p> <p>These results support the hypothesis that cocaine expectancy modulates subjective and objective responses to the drug. Provided the important public health policy implications of heavy cocaine use, health policy makers and clinicians alike may favor cocaine craving assessments performed in the settings with access to the drug rather than in more neutral environments as a more meaningful marker of disease staging and assignment to the proper level of care.</p
Vigilance in a Cooperatively Breeding Primate
Collective vigilance is considered a major advantage of group living in animals. We investigated vigilance behavior in wild mustached tamarins (Saguinus mystax), small, arboreal, cooperatively breeding New World primates that form stable mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We aimed 1) to investigate whether vigilance patterns change according to individual activity and 2) to examine whether there is a social component of vigilance in their cooperative and nonaggressive society. We studied 11 factors that may influence vigilance and used this data to interpret the possible functions of vigilance. We observed 44 individuals in 3 mixed-species and 2 single-species groups of 2 populations that differed in population density and home range sizes. Vigilance changed greatly when individuals were engaged in different activities and individual vigilance was affected by different sets of factors depending on the activity. As vigilance decreased in proximity of conspecifics and heterospecifics when feeding, and in larger mixed-species groups when resting, we conclude that the predominant function of vigilance in mustached tamarins is predator related. However, the absence of the group size effect in very large single-species groups suggests that it may also function to maintain group cohesion. In the population with higher density and smaller home ranges individuals also increased their vigilance in home range overlap areas. We found no evidence that mustached tamarins monitor group mates to avoid food stealing or aggression. The effect of heterospecifics on individual vigilance suggests that collective vigilance might have been an important incentive in the evolution of tamarin mixed-species groups
Identification of Brain Nuclei Implicated in Cocaine-Primed Reinstatement of Conditioned Place Preference: A Behaviour Dissociable from Sensitization
Relapse prevention represents the primary therapeutic challenge in the treatment of drug addiction. As with humans, drug-seeking behaviour can be precipitated in laboratory animals by exposure to a small dose of the drug (prime). The aim of this study was to identify brain nuclei implicated in the cocaine-primed reinstatement of a conditioned place preference (CPP). Thus, a group of mice were conditioned to cocaine, had this place preference extinguished and were then tested for primed reinstatement of the original place preference. There was no correlation between the extent of drug-seeking upon reinstatement and the extent of behavioural sensitization, the extent of original CPP or the extinction profile of mice, suggesting a dissociation of these components of addictive behaviour with a drug-primed reinstatement. Expression of the protein product of the neuronal activity marker c-fos was assessed in a number of brain regions of mice that exhibited reinstatement (R mice) versus those which did not (NR mice). Reinstatement generally conferred greater Fos expression in cortical and limbic structures previously implicated in drug-seeking behaviour, though a number of regions not typically associated with drug-seeking were also activated. In addition, positive correlations were found between neural activation of a number of brain regions and reinstatement behaviour. The most significant result was the activation of the lateral habenula and its positive correlation with reinstatement behaviour. The findings of this study question the relationship between primed reinstatement of a previously extinguished place preference for cocaine and behavioural sensitization. They also implicate activation patterns of discrete brain nuclei as differentiators between reinstating and non-reinstating mice
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Dark energy survey year 1 results: Redshift distributions of the weak-lensing source galaxies
We describe the derivation and validation of redshift distribution estimates and their uncertainties for the populations of galaxies used as weak-lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (BPZ) code is used to assign galaxies to four redshift bins between z β 0.2 and β1.3, and to produce initial estimates of the lensing-weighted redshift distributions nPZi(z) β dni/dz for members of bin i. Accurate determination of cosmological parameters depends critically on knowledge of ni, but is insensitive to bin assignments or redshift errors for individual galaxies. The cosmological analyses allow for shifts ni (z) = nPZi(z - Ξzi) to correct themean redshift of ni(z) for biases in nPZi. The Ξzi are constrained by comparison of independently estimated 30-band photometric redshifts of galaxies in the Cosmic Evolution Survey (COSMOS) field to BPZ estimates made from the DES griz fluxes, for a sample matched in fluxes, pre-seeing size, and lensing weight to the DES weak-lensing sources. In companion papers, the Ξzi of the three lowest redshift bins are further constrained by the angular clustering of the source galaxies around red galaxies with secure photometric redshifts at 0.15 < z < 0.9. This paper details the BPZ and COSMOS procedures, and demonstrates that the cosmological inference is insensitive to details of the ni(z) beyond the choice of Ξzi. The clustering and COSMOS validation methods produce consistent estimates of Ξzi in the bins where both can be applied, with combined uncertainties of ΟΞzi = 0.015, 0.013, 0.011, and 0.022 in the four bins. Repeating the photo-z procedure instead using the Directional Neighbourhood Fitting algorithm, or using the ni(z) estimated from the matched sample in COSMOS, yields no discernible difference in cosmological inferences
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