1,642 research outputs found

    Temperature Mapping of Nitrogen-Doped Niobium Superconducting Radiofrequency Cavities

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    It was recently shown that diffusing nitrogen on the inner surface of superconducting radiofrequency (SRF) cavities at high temperature can improve the quality factor of the niobium cavity. However, a reduction of the quench field is also typically found. To better understand the location of rf losses and quench, we used a thermometry system to map the temperature of the outer surface of ingot Nb cavities after nitrogen doping and electropolishing. Surface temperature of the cavities was recorded while increasing the rf power and also during the quenching. The results of thermal mapping showed no precursor heating on the cavities and quenching to be ignited near the equator where the surface magnetic field is maximum. Hot-spots at the equator area during multipacting were also detected by thermal mapping

    Nitrogen Doping Study in Ingot Niobium Cavities

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    Thermal diffusion of nitrogen in superconducting radio frequency cavities at temperatures around 800C has resulted in the increase in quality factor with a low-field Q-rise. However, the maximum accelerating gradients of these doped cavities often reduces below the values achieved by standard treatments. In this contribution, we present the results of the nitrogen diffusion into ingot niobium cavities subjected to successive material removal from the inner cavity surface by electropolishing in an effort to explore the underlying cause for the gradient degradation

    The winter floods of 2015/2016 in the UK - a review

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    A remarkably persistent and exceptionally mild cyclonic episode beginning in early-November 2015 and lasting around fourteen weeks brought severe, extensive and protracted flooding which impacted most damagingly on northern Britain, Northern Ireland and parts of Wales. Many existing rainfall and seasonal temperature records were eclipsed during this period and, most notably, maximum recorded river flows were exceeded over a substantial proportion of the country. At the national scale, previous maximum daily and monthly outflows were clearly eclipsed and four relatively discrete episodes of extreme runoff can be recognised. In many areas, the magnitude, persistence and repetitive nature of the flooding had major adverse impacts on communities, infrastructure, agriculture and a host of other sectors of the economy. The extent and duration of the flooding has very few close parallels in the historical record and, overall, it was a hydrometeorological episode which ranks alongside the 1975/1976 drought and 1947 floods as the most extreme broad-scale events captured in observational records during the last 100 years at least. The truly exceptional runoff patterns experienced in 1947 and 1976 had a major impact on flood and drought management strategies but occurred before the exacerbating impact of climate change was generally recognised. The 2015/2016 flooding, together with the impact of other protracted flood events in the 21st century thus far, has underlined the need to adapt engineering design and flood management strategies to accommodate the recent extension in the range of recorded runoff variability

    TEDI: the TripleSpec Exoplanet Discovery Instrument

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    The TEDI (TripleSpec - Exoplanet Discovery Instrument) will be the first instrument fielded specifically for finding low-mass stellar companions. The instrument is a near infra-red interferometric spectrometer used as a radial velocimeter. TEDI joins Externally Dispersed Interferometery (EDI) with an efficient, medium-resolution, near IR (0.9 - 2.4 micron) echelle spectrometer, TripleSpec, at the Palomar 200" telescope. We describe the instrument and its radial velocimetry demonstration program to observe cool stars.Comment: 6 Pages, To Appear in SPIE Volume 6693, Techniques and Instrumentation for Detection of Exoplanets II

    Analysing vote choice in a multinational state:National identity and territorial differentiation in the 2016 Brexit vote

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    Striking territorial variations in the 2016 Brexit referendum are neglected in the explanatory literature, a gap our analysis of British Election Study helps to fill. Rather than modelling Britain as one political system, we present parallel models for England, Scotland and Wales. Typical in other multi-national states, this approach is innovative for ‘British politics’. To analyse complex multi-level national identities, we develop a Relative Territorial Identity (RTI) measure. Substantively, RTI predicts Brexit vote-choice. Since voters who prioritise English identity tended to vote Leave, while the obverse was true in Wales and Scotland, RTI helps to explain territorial differentiation

    Control of Synchrotron Radiation Effects During Recirculation With Bunch Compression

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    Studies of beam quality preservation during recirculation * have been extended to generate a design of a compact arc providing bunch compression with positive momentum compaction ** and control of both incoherent and coherent synchrotron radiation (ISR and CSR) effects using the optics balance methods of diMitri et al.***. In addition, the arc/compressor generates very little micro-bunching gain. We detail the beam dynamical basis for the design, discuss the design process, give an example solution, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of micro-bunching effects ****

    Two stages of parafoveal processing during reading: Evidence from a display change detection task

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    We used a display change detection paradigm (Slattery, Angele, & Rayner Human Perception and Performance, 37, 1924–1938 2011) to investigate whether display change detection uses orthographic regularity and whether detection is affected by the processing difficulty of the word preceding the boundary that triggers the display change. Subjects were significantly more sensitive to display changes when the change was from a nonwordlike preview than when the change was from a wordlike preview, but the preview benefit effect on the target word was not affected by whether the preview was wordlike or nonwordlike. Additionally, we did not find any influence of preboundary word frequency on display change detection performance. Our results suggest that display change detection and lexical processing do not use the same cognitive mechanisms. We propose that parafoveal processing takes place in two stages: an early, orthography-based, preattentional stage, and a late, attention-dependent lexical access stage

    Evaluation and Treatment in Urology for Nocturia Caused by Nonurological Mechanisms:Guidance from the PLANET Study

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    Patients with nocturia are commonly referred to urology clinics, including many for whom a nonurological medical condition is responsible for their symptoms. The PLanning Appropriate Nocturia Evaluation and Treatment (PLANET) study was established to develop practical approaches to equip healthcare practitioners to deal with the diverse causes of nocturia, based on systematic reviews and expert consensus. Initial assessment and therapy need to consider the possibility of one or more medical conditions falling into the “SCREeN” areas of Sleep medicine (insomnia, periodic limb movements of sleep, parasomnias, and obstructive sleep apnoea), Cardiovascular (hypertension and congestive heart failure), Renal (chronic kidney disease), Endocrine (diabetes mellitus, thyroid disease, pregnancy/menopause, and diabetes insipidus), and Neurology. Medical and medication causes of xerostomia should also be considered. Some key indicators for these conditions can be identified in urology clinics, working in partnership with the primary care provider. Therapy of the medical condition in some circumstances lessens the severity of nocturia. However, in many cases there is a conflict between the two, in which case the medical condition generally takes priority on safety grounds. It is important to provide patients with a realistic expectation of therapy and awareness of limitations of current therapeutic options for nocturia.Patient summaryNocturia is the symptom of waking at night to pass urine. Commonly, this problem is referred to urology clinics. However, in some cases, the patient does not have a urological condition but actually a condition from a different speciality of medicine. This article describes how best the urologist and the primary care doctor can work together to assess the situation and make sensible and safe treatment suggestions. Unfortunately, there is sometimes no safe or effective treatment choice for nocturia, and treatment needs to focus instead on supportive management of symptoms

    Surface Chemistry of Perfluoropolyethers and Hydrogenated Analogs: Are Studies of Model Compounds Useful?

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    We have studied adsorption, desorption, and decomposition of ethers on Ru(001), an atomically-smooth metal surface. We have compared diethers with monoethers, and fluorinated ethers with hydrogenated ethers. The number of ether linkages does not strongly influence adsorption bond strength, nor the extent of decomposition. Fluorination does weaken the adsorption bond strength and prevents decomposition. These studies suggest that the surface properties of monomeric ethers can be used to predict properties of oligomeric, and perhaps even polymeric, ethers

    Impact of psychiatric comorbidity on treatment of adolescent drug abusers

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    Abstract Comorbidity of substance abuse disorders (SUD) and psychiatric disorders is one of the most important areas of investigation in contemporary drug abuse treatment research. This study examined the impact of psychiatric comorbidity on the treatment of 182 adolescent drug abusers in a randomized clinical trial comparing family and individual cognitive-behavioral therapy. Three distinct groups of adolescent substance abusers were compared: (1) Exclusive Substance Abusers (SUD only); (2) Externalizers (SUD + externalizing disorder); and (3) Mixed Substance Abusers (SUD + externalizing and internalizing disorder). The purpose of this study was to determine whether adolescents in these comorbid groups differed in clinical presentation and treatment response. More severe comorbidity was associated with greater family dysfunction and being female and younger at intake. An examination of substance use trajectories over time indicated that the Mixed group initially responded to treatment but returned to intake levels of substance use by 1 year post-discharge.
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