14,571 research outputs found

    Star-forming Galaxies in the 'Redshift Desert'

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    We describe results of optical and near-IR observations of a large spectroscopic sample of star-forming galaxies photometrically-selected to lie in the redshift range 1.4 < z < 2.5, often called the ``redshift desert'' because of historical difficulty in obtaining spectroscopic redshifts in this range. We show that the former ``redshift desert'' is now very much open to observation.Comment: 10 pages, 6 figures, to appear in the Proceedings of the ESO/USM/MPE Workshop on "Multiwavelength Mapping of Galaxy Formation and Evolution", eds. R. Bender and A. Renzin

    Processingâ Dependent Microstructure of AgClâ CsAgCl2 Eutectic Photonic Crystals

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    Directional solidification of a eutectic melt allows control over the resultant eutectic microstructure, which in turn impacts both the mechanical and optical properties of the material. These selfâ organized phaseâ separated eutectic materials can be tuned to have periodicities from tens of micrometers down to nanometers. Furthermore, the two phases possess differences in their refractive index leading to interesting optical properties that can be tailored within the visible to infrared wavelength regime. It is found the binary salt eutectic AgClâ CsAgCl2 system forms a rod microstructure with sample draw rates up to 0.2 mm sâ 1 which transitions to a lamellar microstructure at draw rates greater than 0.36 mm sâ 1. Heatâ transfer simulations reveal a draw rateâ dependent direction of motion of the solidification front, which for a range of draw rates requires nucleation of the minority solid phase at the sample wall. Phaseâ field modeling indicates that the initial eutectic structure at the sample boundary, either rod or lamellar, dictates the bulk eutectic morphology. These samples contain submicrometer periodicities which coupled with their optical transparency results in them exhibiting draw rateâ dependent nearâ IR reflectance peaks consistent with stop bands for 2D hexagonal (rod) and 1D planar (lamellar) photonic crystals.The eutectic composition of the molten salts AgCl and CsCl exhibits a microstructural transition from rod to lamellar upon varying the draw rates controlled by directional solidification. This transition is dominated by the initial formation at the surface of either the rod or lamellar structure. The resultant eutectic microstructures have optical properties consistent with their being 2D and 1D photonic crystals.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145412/1/adom201701316.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145412/2/adom201701316_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145412/3/adom201701316-sup-0001-S1.pd

    Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

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    Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

    A gender-sensitised weight loss and healthy living programme for overweight and obese men delivered by Scottish Premier League football clubs (FFIT): a pragmatic randomised controlled trial.

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    BACKGROUND: The prevalence of male obesity is increasing but few men take part in weight loss programmes. We assessed the effect of a weight loss and healthy living programme on weight loss in football (soccer) fans. METHODS: We did a two-group, pragmatic, randomised controlled trial of 747 male football fans aged 35-65 years with a body-mass index (BMI) of 28 kg/m(2) or higher from 13 Scottish professional football clubs. Participants were randomly assigned with SAS (version 9¡2, block size 2-9) in a 1:1 ratio, stratified by club, to a weight loss programme delivered by community coaching staff in 12 sessions held every week. The intervention group started a weight loss programme within 3 weeks, and the comparison group were put on a 12 month waiting list. All participants received a weight management booklet. Primary outcome was mean difference in weight loss between groups at 12 months, expressed as absolute weight and a percentage of their baseline weight. Primary outcome assessment was masked. Analyses were based on intention to treat. The trial is registered with Current Controlled Trials, number ISRCTN32677491. FINDINGS: 374 men were allocated to the intervention group and 374 to the comparison group. 333 (89%) of the intervention group and 355 (95%) of the comparison group completed 12 month assessments. At 12 months the mean difference in weight loss between groups, adjusted for baseline weight and club, was 4¡94 kg (95% CI 3¡95-5¡94) and percentage weight loss, similarly adjusted, was 4¡36% (3¡64-5¡08), both in favour of the intervention (p<0¡0001). Eight serious adverse events were reported, five in the intervention group (lost consciousness due to drugs for pre-existing angina, gallbladder removal, hospital admission with suspected heart attack, ruptured gut, and ruptured Achilles tendon) and three in the comparison group (transient ischaemic attack, and two deaths). Of these, two adverse events were reported as related to participation in the programme (gallbladder removal and ruptured Achilles tendon). INTERPRETATION: The FFIT programme can help a large proportion of men to lose a clinically important amount of weight; it offers one effective strategy to challenge male obesity. FUNDING: Scottish Government and The UK Football Pools funded delivery of the programme through a grant to the Scottish Premier League Trust. The National Institute for Health Research Public Health Research Programme funded the assessment (09/3010/06)

    Fluid flow at the interface between elastic solids with randomly rough surfaces

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    I study fluid flow at the interface between elastic solids with randomly rough surfaces. I use the contact mechanics model of Persson to take into account the elastic interaction between the solid walls and the Bruggeman effective medium theory to account for the influence of the disorder on the fluid flow. I calculate the flow tensor which determines the pressure flow factor and, e.g., the leak-rate of static seals. I show how the perturbation treatment of Tripp can be extended to arbitrary order in the ratio between the root-mean-square roughness amplitude and the average interfacial surface separation. I introduce a matrix D(Zeta), determined by the surface roughness power spectrum, which can be used to describe the anisotropy of the surface at any magnification Zeta. I present results for the asymmetry factor Gamma(Zeta) (generalized Peklenik number) for grinded steel and sandblasted PMMA surfaces.Comment: 16 pages, 14 figure

    Technology-delivered undergraduate medical education involving patients and carers: A rapid systematic review

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    Background: Involving patients and carers in medical education centralises their voice in healthcare and supports students to develop key professional and person-centred skills. Medical schools are increasingly using technology to deliver educational activities. No review currently exists to establish the variety of technologies and their uses in undergraduate medical education when patients and/or carers are involved. / Methods: Ovid MEDLINE, Ovid EMBASE and medRxiv were searched in October 2020 and reference lists of key articles were hand searched. Eligible studies reported technology-assisted education, in any setting, involving authentic patients and/or carers. Studies in foreign languages, or describing actors or non-authentic patients were excluded. Study quality was assessed using the Mixed Methods Appraisal Tool (MMAT). Levels of patient involvement were assessed using Towle et al (2010) taxonomy. / Results: Twenty studies were included. The majority involved patients and/or carers via pre-recorded videos or online scenarios, with no student-interaction. Four studies evaluated remote consultations using telehealth technology, involving real-time interactions with authentic patients. Technology-supported teaching sessions involving patients and/or carers were found to be acceptable to students, educationally valuable (to students and educators), and enhanced student engagement, patient-centred attitudes, knowledge of specific patient groups, and communication and clinical skills. Two studies describing real-time remote interactions with authentic patients indicated potential barriers for students (reduced ability to build relationship with patients and examine them), educators (reduced ability to build rapport with students) and patients (issues with using or accessing telehealth). / Conclusions: No studies directly measured the perspective of patients or carers involved in technology-delivered medical education. Future research should establish barriers and facilitators to patients and carers taking up a role in medical students education when technology is used, and evaluate PPI activities at Levels 3 and above as described by Towle et al taxonomy

    The Origin of Power-Law Emergent Scaling in Large Binary Networks

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    In this paper we study the macroscopic conduction properties of large but finite binary networks with conducting bonds. By taking a combination of a spectral and an averaging based approach we derive asymptotic formulae for the conduction in terms of the component proportions p and the total number of components N. These formulae correctly identify both the percolation limits and also the emergent power law behaviour between the percolation limits and show the interplay between the size of the network and the deviation of the proportion from the critical value of p = 1/2. The results compare excellently with a large number of numerical simulations

    17O NMR study of q=0 spin excitations in a nearly ideal S=1/2 1D Heisenberg antiferromagnet, Sr2CuO3, up to 800 K

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    We used 17O NMR to probe the uniform (wavevector q=0) electron spin excitations up to 800 K in Sr2CuO3 and separate the q=0 from the q=\pm\pi/a staggered components. Our results support the logarithmic decrease of the uniform spin susceptibility below T ~ 0.015J, where J=2200 K. From measurement of the dynamical spin susceptibility for q=0 by the spin-lattice relaxation rate 1/T_{1}, we demonstrate that the q=0 mode of spin transport is ballistic at the T=0 limit, but has a diffusion-like contribution at finite temperatures even for T << J.Comment: Submitted to Phys. Rev. Lett. 4 pages, 4 figure

    Cosmic Voids: structure, dynamics and galaxies

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    In this review we discuss several aspects of Cosmic Voids. Voids are a major component of the large scale distribution of matter and galaxies in the Universe. They are of instrumental importance for understanding the emergence of the Cosmic Web. Their relatively simple shape and structure makes them into useful tools for extracting the value of a variety cosmic parameters, possibly including even that of the influence of dark energy. Perhaps most promising and challenging is the issue of the galaxies found within their realm. Not only does the pristine environment of voids provide a promising testing ground for assessing the role of environment on the formation and evolution of galaxies, the dearth of dwarf galaxies may even represent a serious challenge to the standard view of cosmic structure formation.Comment: 29 pages, 12 figures, invited review COSPA2008, Pohang, Korea. Modern Physics Letters A, accepted. For high-res version see http://www.astro.rug.nl/~weygaert/voids.cospa2008.weygaert.pd
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