1,377 research outputs found
The RFOFO Ionization Cooling Ring for Muons
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
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
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
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
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
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
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
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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