3,439 research outputs found

    On the properties of superconducting planar resonators at mK temperatures

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    Planar superconducting resonators are now being increasingly used at mK temperatures in a number of novel applications. They are also interesting devices in their own right since they allow us to probe the properties of both the superconductor and its environment. We have experimentally investigated three types of niobium resonators - including a lumped element design - fabricated on sapphire and SiO_2/Si substrates. They all exhibit a non-trivial temperature dependence of their centre frequency and quality factor. Our results shed new light on the interaction between the electromagnetic waves in the resonator and two-level fluctuators in the substrate.Comment: V2 includes some minor corrections/changes. Submitted to PR

    Magnetic field tuning of coplanar waveguide resonators

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    We describe measurements on microwave coplanar resonators designed for quantum bit experiments. Resonators have been patterned onto sapphire and silicon substrates, and quality factors in excess of a million have been observed. The resonant frequency shows a high sensitivity to magnetic field applied perpendicular to the plane of the film, with a quadratic dependence for the fundamental, second and third harmonics. Frequency shift of hundreds of linewidths can be obtained.Comment: Accepted for publication in AP

    Circuit QED with a Flux Qubit Strongly Coupled to a Coplanar Transmission Line Resonator

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    We propose a scheme for circuit quantum electrodynamics with a superconducting flux-qubit coupled to a high-Q coplanar resonator. Assuming realistic circuit parameters we predict that it is possible to reach the strong coupling regime. Routes to metrological applications, such as single photon generation and quantum non-demolition measurements are discussed.Comment: 8 pages, 5 figure

    Re: Sleep and the Family Doctor: Time to Lead

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    Psychosocial Correlates of Insomnia Severity in Primary Care

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    Purpose: Insomnia is a substantive primary care issue that leads to adverse outcomes. These can be improved by addressing factors that accentuate insomnia severity. Accordingly, this study identifies correlates of insomnia severity and determines whether these relationships vary with sociodemographic attributes. Methods: This correlational cross-sectional study was conducted in a hospital-sponsored primary care clinic and 2 urban, academic family practice centers. Participants consisted of 236 patients 18 years old or older with clinically significant insomnia (Insomnia Severity Index scores of 7 or more). Surveys instruments included the Insomnia Severity Index, SF-8 (Medical Outcomes Study SF-8 global health status measure), CES-D (Center for Epidemiologic Studies-Depression Scale), DBAS (Dysfunctional Beliefs about Sleep scale), SE-S (Self-Efficacy for Sleep Scale), and a researcher-designed demographic survey. Analytic techniques included descriptive statistics to characterize the study sample, Pearson or Spearman Correlation Coefficients to examine individual associations with insomnia severity, and step-wise linear regression to identify net predictors. Results: Insomnia severity was significantly correlated with health status, depression, self-efficacy, and dysfunctional beliefs (P \u3c .001) but not with sociodemographic attributes. Linear regression demonstrated insomnia severity was best predicted by low self-efficacy and high depression scores. Discussion: These findings indicate that clinicians treating insomnia should not only manage comorbid depression but also facilitate self-efficacy for sleep-inducing behavioral change

    Acceptability of Behavioral Treatments for Insomnia

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    Background: Behavioral treatments for insomnia are safe and efficacious but may not be embraced by patients in primary care. Understanding factors associated with acceptability can enhance successful use of these modalities. The objective of this study was to identify demographic and clinical/psychosocial correlates of behavioral insomnia treatment acceptability. Methods: This nonexperimental, inventory-based, cross-sectional study enrolled patients from a hospital-sponsored primary care clinic and 2 urban academic family practices. Participants (n = 236) were 18 years of age or older who had clinically significant insomnia (Insomnia Severity Index score \u3e= 8) and were recruited consecutively at these sites. A study coordinator obtained informed consent then distributed survey materials. Participants received a $10 honorarium. The main outcome measure was the Acceptability Insomnia Treatment Acceptability Scale-Behavioral subscale (ITAS-B). Results: Only acceptability of medications (r = 0.259) and dysfunctional beliefs (r = 0.234) scores had significant bivariate correlations with ITAS-B scores (P \u3c .001). Medication acceptability, dysfunctional beliefs, and self-efficacy accounted for 12.45% of ITAS-B variance in linear regression. Conclusions: Screening for dysfunctional beliefs about sleep may identify patients with interest in behavioral approaches. Improving self-efficacy for sleep may improve acceptance of behavioral insomnia therapies. Interest in behavioral and medication treatments are not mutually exclusive. However, the modest variance reported here suggests other factors impact acceptance of behavioral treatments

    CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates

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    We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray AGN. The defined sample has 1625 targets with radio and X-ray properties similar to those of the EGRET blazars, spread uniformly across the |b| > 10 deg sky. We also report progress toward optical characterization of the sample; of objects with known R < 23, 85% have been classified and 81% have measured redshifts. One goal of this program is to focus attention on the most interesting (e.g., high redshift, high luminosity, ...) sources for intensive multiwavelength study during the observations by the Large Area Telescope (LAT) on GLAST.Comment: 18 pages, 6 figures, 1 machine-readable table available at http://astro.stanford.edu/CGRaBS/ ; accepted for publication in ApJ

    Drawing as transcription: how do graphical techniques inform interaction analysis?

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    This is an Open Access Article. It is published by Aarhus University Library under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Drawing as a form of analytical inscription can provide researchers with highly flexible methods for exploring embodied interaction. Graphical techniques can combine spatial layouts, trajectories of action and anatomical detail, as well as rich descriptions of movement and temporal effects. This paper introduces some of the possibilities and challenges of adapting graphical techniques from life drawing and still life for interaction research. We demonstrate how many of these techniques are used in interaction research by illustrating the postural configurations and movements of participants in a ballet class. We then discuss a prototype software tool that is being developed to support interaction analysis specifically in the context of a collaborative data analysis session

    Improving reintroduction success in large carnivores through individual-based modelling: How to reintroduce Eurasian lynx (Lynx lynx) to Scotland

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    Globally, large carnivores have been heavily affected by habitat loss, fragmentation and persecution, sometimes resulting in local extinctions. With increasing recognition of top-down trophic cascades and complex predator- prey dynamics, reintroductions are of growing interest for restoration of ecosystem functioning. Many re- introductions have however failed, in part due to poor planning and inability to model complex eco-evolutionary processes to give reliable predictions. Using the case study of Eurasian lynx (Lynx lynx), a large predator being considered for reintroduction to Scotland, we demonstrate how an individual-based model that integrates demography with three distinct phases of dispersal (emigration, transfer and settlement) can be used to explore the relative suitability of three geographically-distant potential reintroduction sites, multi-site reintroductions and two founding population sizes. For a single-site reintroduction of 10 lynx, our simulation results show a clear hierarchy of suitability across all metrics. Reintroduction in the Kintyre Peninsula (west coast) consistently performed best, with a probability of population persistence at year 100 of 83%, and the Scottish component of Kielder Forest (southern Scotland) worst, with only a 21% chance of population persistence to year 100. Simultaneous two-site reintroduction in the Kintyre Peninsula and in Aberdeenshire (near the east coast) of 32 lynx gave a 96% persistence at 100 years. Our model was highly sensitive to survival, particularly of adults, highlighting this parameter's importance for reintroduction success. The results strongly indicate the potential viability of Eurasian lynx reintroduction to Scotland given the current cover of suitable woodland habitat. More generally, our work demonstrates how emerging modelling approaches incorporating increased realism in re- presenting species' demography, ecology and dispersal can have high value for quick, inexpensive assessment of likely reintroduction success and for selection between alternative strategies.REF Compliant by Deposit in Stirling's Repositor

    Identification and quantification of drivers of forest degradation in tropical dry forests: a case study in Western Mexico

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    The intensity of forest degradation is linked to landowners' decisions on management of their shifting cultivation systems. Understanding the processes involved in this land use type is therefore essential for the design of sustainable forest management practices. However, knowledge of the processes and patterns of forest transition that result from this practice is extremely limited. In this study, we used spatially-explicit binary logistic regression to study the proximate factors that relate to forest degradation by combining biophysical and socio-economic variables. Our study region is within the Ayuquila Basin, in Western Mexico, a typical fragmented tropical dry forest landscape dominated by shifting cultivation. Through a survey and semi-structured interviews with community leaders, we obtained data on the forest resources and on the uses that people make of them. Detailed forest cover maps for 2004 and 2010 were produced from high-resolution SPOT 5 data, and ancillary geographical data were used to extract spatial variables. The degree of social marginalization of each community and the ratio of forest area to population size were the main factors positively correlated with the probability of the occurrence of forest degradation. Livestock management and use of fence posts by the communities were also positively associated with forest degradation. Among biophysical factors, forest degradation is more likely to occur in flatter areas. We conclude that local drivers of forest degradation include both socioeconomic and physical variables and that both of these factors need to be addressed at the landscape level while developing measures for activities related to REDD+. (C) 2015 Elsevier Ltd. All rights reserved
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