832 research outputs found
The effect of phase fluctuations on the single-particle properties of the underdoped cuprates
We study the effect of order parameter phase fluctuations on the
single-particle properties of fermions in the underdoped cuprate
superconductors using a phenomenological low-energy theory. We identify the
fermion-phase field coupling as the Doppler-shift of the quasiparticle spectrum
induced by the fluctuating superfluid velocity and we calculate the effect of
these fluctuations on the fermion self-energy. We show that the vortex pair
unbinding near the superconducting transition causes a significant broadening
in the fermion spectral function, producing a pseudogap-like feature. We also
discuss the specific heat and show that the phase fluctuation effect is visible
due to the short coherence length.Comment: RevTex 11 pages; 11 epsf figures included. Added and updated
reference
Hubble Space Telescope Imaging of Lyman Alpha Emission at z=4.4
We present the highest redshift detections of resolved Lyman alpha emission,
using Hubble Space Telescope/ACS F658N narrowband-imaging data taken in
parallel with the Wide Field Camera 3 Early Release Science program in the
GOODS CDF-S. We detect Lyman alpha emission from three spectroscopically
confirmed z = 4.4 Lyman alpha emitting galaxies (LAEs), more than doubling the
sample of LAEs with resolved Lyman alpha emission. Comparing the light
distribution between the rest-frame ultraviolet continuum and narrowband
images, we investigate the escape of Lyman alpha photons at high redshift.
While our data do not support a positional offset between the Lyman alpha and
rest-frame ultraviolet (UV) continuum emission, the half-light radii in two out
of the three galaxies are significantly larger in Lyman alpha than in the
rest-frame UV continuum. This result is confirmed when comparing object sizes
in a stack of all objects in both bands. Additionally, the narrowband flux
detected with HST is significantly less than observed in similar filters from
the ground. These results together imply that the Lyman alpha emission is not
strictly confined to its indigenous star-forming regions. Rather, the Lyman
alpha emission is more extended, with the missing HST flux likely existing in a
diffuse outer halo. This suggests that the radiative transfer of Lyman alpha
photons in high-redshift LAEs is complicated, with the interstellar-medium
geometry and/or outflows playing a significant role in galaxies at these
redshifts.Comment: Submitted to the Astrophysical Journal. 11 pages, 10 figure
Collaborative learning about e-health for mental health professionals and service users in a structured anonymous online short course: pilot study.
BACKGROUND: Professionals are interested in using e-health but implementation of new methods is slow. Barriers to implementation include the need for training and limited awareness or experience. Research may not always convince mental health professionals (MHPs). Adding the 'voice' of mental health service users (MHSUs) in collaborative learning may help. Involving MHSUs in face-face education can be difficult. We had previously been unable to engage MHPs in online discussion with MHSUs. Here we assessed the feasibility of short online courses involving MHSUs and MHPs. METHODS: We ran three e-health courses, comprising live interactive webcast, week's access to a discussion forum, and final live interactive webcast. We recruited MHPs via posters, newsletters, and telephone from a local NHS trust, and online via mailing lists and personal contacts from NHS trusts and higher education. We recruited MHSUs via a previous project and an independent user involvement service. Participants were presented with research evidence about e-health and asked to discuss topics using professional and lived experience. Feasibility was assessed through recruitment and attrition, participation, and researcher workloads. Outcomes of self-esteem and general self-efficacy (MHSUs), and Internet self-efficacy and confidence (MHPs) were piloted. RESULTS: Online recruiting was effective. We lost 15/41 from registration to follow-up but only 5/31 that participated in the course failed to complete follow-up. Nineteen MHPs and 12 MHSUs took part and engaged with each other in online discussion. Feedback was positive; three-quarters of MHPs indicated future plans to use the Internet for practice, and 80% of MHSUs felt the course should be continued. Running three courses for 31 participants took between 200 to 250 hours. Before and after outcome measures were completed by 26/31 that participated. MHP Internet self-efficacy and general Internet confidence, MHSU self-esteem and general self-efficacy, all seemed reliable and seemed to show some increase. CONCLUSIONS: Collaborative learning between MHSUs and MHPs in a structured online anonymous environment over a one-week course is feasible, may be more practical and less costly than face-face methods, and is worthy of further study
Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity
Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria
Fish and macroinvertebrate assemblages reveal extensive degradation of the world's rivers
Rivers suffer from multiple stressors acting simultaneously on their biota, but the consequences are poorly quantified at the global scale. We evaluated the biological condition of rivers globally, including the largest proportion of countries from the Global South published to date. We gathered macroinvertebrate- and fish-based assessments from 72,275 and 37,676 sites, respectively, from 64 study regions across six continents and 45 nations. Because assessments were based on differing methods, different systems were consolidated into a 3-class system: Good, Impaired, or Severely Impaired, following common guidelines. The proportion of sites in each class by study area was calculated and each region was assigned a Köppen-Geiger climate type, Human Footprint score (addressing landscape alterations), Human Development Index (HDI) score (addressing social welfare), % rivers with good ambient water quality, % protected freshwater key biodiversity areas; and % of forest area net change rate. We found that 50% of macroinvertebrate sites and 42% of fish sites were in Good condition, whereas 21% and 29% were Severely Impaired, respectively. The poorest biological conditions occurred in Arid and Equatorial climates and the best conditions occurred in Snow climates. Severely Impaired conditions were associated (Pearson correlation coefficient) with higher HDI scores, poorer physico-chemical water quality, and lower proportions of protected freshwater areas. Good biological conditions were associated with good water quality and increased forested areas. It is essential to implement statutory bioassessment programs in Asian, African, and South American countries, and continue them in Oceania, Europe, and North America. There is a need to invest in assessments based on fish, as there is less information globally and fish were strong indicators of degradation. Our study highlights a need to increase the extent and number of protected river catchments, preserve and restore natural forested areas in the catchments, treat wastewater discharges, and improve river connectivity
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Surgery for benign insulinoma: An international review
In a multiinstitutional review, data on 396 patients with benign solitary or multiple insulinomas operated on in 15 centers were collected. In these 396 patients, 419 laparotomies (375 primary procedures and 44 reoperations) were performed. The rate of unnecessary laparotomies was 1.7%. Complications occurred after 132 operations (31.5%), requiring 27 reinterventions (6.4%). Ten (2%) patients died within 30 days of surgery. The success rate of first procedures in the centers was 94.9%. After reoperation, all but 2 (99.5%) of these patients were cured. The overall cure rate including those patients who had their primary operations elsewhere was 97.5% . Compilant les dossiers de 15 établissements internationaux, nous avons colligé les données concernant 396 patients présentant un insulinome bénin unique ou multiple, opérés. Chez ces 396 patients, 419 laparotomies (375 interventions de première intention et 44 reprises) ont été effectuées. Le taux de laparotomie inutile était de 1.7%. Des complications sont intervenues à la suite de 132 opérations (31.5%), nécessitant 27 réinterventions (6.4%). Dix (2%) patients sont morts dans les trente jours après l'acte chirurgical. Le taux de succès des interventions de première intention dans les centres de l'étude était de 94.9%. Après réinterventions, tous les patients sauf 2 (99.5%) ont été guéris. Le taux global de guérison, y compris les patients ayant été opérés une première fois ailleurs, était de 97.5%. En una revisión multiinstitucional se recolectaron los datos sobre 396 pacientes con insulinomas benignos solitarios o múltiples operados en 15 centros. En estos 396 pacientes se efectuaron 419 laparotomÃas (375 procedimientos primarios y 44 reoperaciones). Se registró una tasa de laparotomÃas innecesarias de 1.7%; se presentaron complicaciones después de 132 operaciones (31.5%), las cuales requirieron 27 reintervenciones (6.4%). Diez (2%) pacientes murieron dentro de los primeras 30 dÃas después de la cirugÃa. La tasa de éxito del procedimiento primario realizado en estos centros fue 94.9%. Después de las reoperaciones la totalidad de los pacientes, menos 2 (99.5%), fueron curados. La tasa global de curación, incluyendo los que tuvieron su operación primaria por fuera de los centros del estudio, fue 97.5%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41289/1/268_2005_Article_BF01658536.pd
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