1,377 research outputs found

    The RFOFO Ionization Cooling Ring for Muons

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    Practical ionization cooling rings could lead to lower cost or improved performance in neutrino factory or muon collider designs. The ring modeled here uses realistic three-dimensional fields. The performance of the ring compares favorably with the linear cooling channel used in the second US Neutrino Factory Study. The normalized 6D emittance of an ideal ring is decreased by a factor of approximately 240, compared with a factor of only 15 for the linear channel. We also examine such \textit{real-world} effects as windows on the absorbers and rf cavities and leaving empty lattice cells for injection and extraction. For realistic conditions the ring decreases the normalized 6D emittance by a factor of 49.Comment: 27 pages, 18 figures and 5 tables. Submitted to Phys. Rev. ST-A

    From nonwetting to prewetting: the asymptotic behavior of 4He drops on alkali substrates

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    We investigate the spreading of 4He droplets on alkali surfaces at zero temperature, within the frame of Finite Range Density Functional theory. The equilibrium configurations of several 4He_N clusters and their asymptotic trend with increasing particle number N, which can be traced to the wetting behavior of the quantum fluid, are examined for nanoscopic droplets. We discuss the size effects, inferring that the asymptotic properties of large droplets correspond to those of the prewetting film

    Permanent pacemaker dependency in patients with new left bundle branch block and new first degree atrioventricular block after transcatheter aortic valve implantation

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    Conduction disorders with need for permanent pacemaker (PPM) implantation remain frequent complications after transcatheter aortic valve implantation (TAVI). Up to 22% of PPM after TAVI are implanted for new onset left bundle branch block (LBBB) and atrioventricular block (AVB) I. However, clinical benefit and predictors of ventricular pacing in TAVI patients receiving PPM for this indication remain unclear. We retrospectively evaluated pacemaker interrogation data of patients who received a PPM post TAVI for new LBBB and new AVB I. The primary endpoint of this study was relevant ventricular pacing (ventricular pacing rate: Vp ≥ 1%) at the first outpatient pacemaker interrogation. Secondary endpoints were predictors for relevant ventricular pacing. At the first pacemaker interrogation (median follow up at 6.23 2.8-14.8 months), median ventricular pacing frequency was 1.0{\%} 0.1-17.8. Out of 61 patients, 36 (59{\%}) had Vp rates ≥ 1{\%}. Patients with frequent ventricular pacing showed longer QRS duration (155~ms ± 17~ms vs. 144~ms ± 18~ms, p = 0.018) at the time of PPM implantation and were less likely treated with a balloon-expandable Edwards Sapiens Valve (39{\%} vs. 12{\%}, p = 0.040). Our findings suggest that the majority of patients with new LBBB and new AVB I after TAVI show relevant ventricular pacing rates at follow up. Further prospective studies are necessary to identify patients at higher risk of pacemaker dependency

    Adaptation of the Structured Clinical Interview for DSM-IV Disorders for assessing depression in women during pregnancy and post-partum across countries and cultures

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    BackgroundTo date, no study has used standardised diagnostic assessment procedures to determine whether rates of perinatal depression vary across cultures.AimsTo adapt the Structured Clinical Interview for DSM–IV Disorders (SCID) for assessing depression and other non-psychotic psychiatric illness perinatally and to pilot the instrument in different centres and cultures.MethodAssessments using the adapted SCID and the Edinburgh Postnatal Depression Scale were conducted during the third trimester of pregnancy and at 6 months postpartum with 296 women from ten sites in eight countries. Point prevalence rates during pregnancy and the postnatal period and adjusted 6-month period prevalence rates were computed for caseness, depression and major depression.ResultsThe third trimester and 6-month point prevalence rates for perinatal depression were 6.9% and 8.0%, respectively. Postnatal 6-month period prevalence rates for perinatal depression ranged from 2.1% to 31.6% across centres and there were significant differences in these rates between centres.ConclusionsStudy findings suggest that the SCID was successfully adapted for this context. Further research on determinants of differences inprevalence of depression across cultures isneeded

    Postnatal depression across countries and cultures : a qualitative study

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    Background: Postnatal depression seems to be a universal condition with similar rates in different countries. However, anthropologists question the cross-cultural equivalence of depression, particularly at a life stage so influenced by cultural factors. Aims: To develop a qualitative method to explore whether postnatal depression is universally recognised, attributed and described and to enquire into people’s perceptions of remedies and services for morbid states of unhappiness within the context of local services. Method: The study took place in 15 centres in 11 countries and drew on three groups of informants: focus groups with new mothers, interviews with fathers and grandmothers, and interviews with health professionals.Textual analysis of these three groups was conducted separately in each centre and emergent themes compared across centres. Results: All centres described morbid unhappiness after childbirth comparable to postnatal depression but not all saw this as an illness remediable by health interventions. Conclusions: Although the findings of this study support the universality of a morbid state of unhappiness following childbirth, they also support concerns about the cross-cultural equivalence of postnatal depression as an illness requiring the intervention of health professionals; this has implications for future research

    Dynamics of liquid He-4 in confined geometries from Time-Dependent Density Functional calculations

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    We present numerical results obtained from Time-Dependent Density Functional calculations of the dynamics of liquid He-4 in different environments characterized by geometrical confinement. The time-dependent density profile and velocity field of He-4 are obtained by means of direct numerical integration of the non-linear Schrodinger equation associated with a phenomenological energy functional which describes accurately both the static and dynamic properties of bulk liquid He-4. Our implementation allows for a general solution in 3-D (i.e. no symmetries are assumed in order to simplify the calculations). We apply our method to study the real-time dynamics of pure and alkali-doped clusters, of a monolayer film on a weakly attractive surface and a nano-droplet spreading on a solid surface.Comment: q 1 tex file + 9 Ps figure

    Health services research into postnatal depression : results from a preliminary cross-cultural study

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    Background: Little is known about the availability and uptake of health and welfare services by women with postnatal depression in different countries. Aims: Within the context of a cross- cultural research study, to develop and test methods for undertaking quantitative health services research in postnatal depression. Method: Interviews with service planners and the collation of key health indicators were used to obtain a profile of service availability and provision. A service use questionnaire was developed and administered to a pilot sample in a number of European study centres. Results: Marked differences in service access and use were observed between the centres, including postnatal nursing care and contacts with primary care services.Rates of use of specialist services were generally low.Common barriers to access to care included perceived service quality and responsiveness. On the basis of the pilot work, a postnatal depression version of the Service Receipt Inventory was revised and finalised. Conclusions: This preliminary study demonstrated the methodological feasibility of describing and quantifying service use, highlighted the varied and often limited use of care in this population, and indicated the need for an improved understanding of the resource needs and implications of postnatal depression

    Threshold criterion for wetting at the triple point

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    Grand canonical simulations are used to calculate adsorption isotherms of various classical gases on alkali metal and Mg surfaces. Ab initio adsorption potentials and Lennard-Jones gas-gas interactions are used. Depending on the system, the resulting behavior can be nonwetting for all temperatures studied, complete wetting, or (in the intermediate case) exhibit a wetting transition. An unusual variety of wetting transitions at the triple point is found in the case of a specific adsorption potential of intermediate strength. The general threshold for wetting near the triple point is found to be close to that predicted with a heuristic model of Cheng et al. This same conclusion was drawn in a recent experimental and simulation study of Ar on CO_2 by Mistura et al. These results imply that a dimensionless wetting parameter w is useful for predicting whether wetting behavior is present at and above the triple temperature. The nonwetting/wetting crossover value found here is w circa 3.3.Comment: 15 pages, 8 figure
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