139 research outputs found
Dephasing Times in a Non-degenerate Two-Dimensional Electron Gas
Studies of weak localization by scattering from vapor atoms for electrons on
a liquid helium surface are reported. There are three contributions to the
dephasing time. Dephasing by the motion of vapor atoms perpendicular to the
surface is studied by varying the holding field to change the characteristic
width of the electron layer at the surface. A change in vapor density alters
the quasi-elastic scattering length and the dephasing due to the motion of
atoms both perpendicular and parallel to the surface. Dephasing due to the
electron-electron interaction is dependent on the electron density.Comment: 4 pages, Revte
Calcaneal nonunion: three cases and a review of the literature
The long-term follow-up of intra-articular calcaneal fractures is often accompanied by complications. Frequently occurring are arthrosis, arthrofibrosis of the subtalar joint, and malunion. Uncommon is the calcaneal nonunion. A total of three cases is presented in this report, including a review of the literature. The occurrence of a nonunion appears to be more common after conservative treatment, but the pathophysiology remains unclear, however smoking may play a role
ADVANCE integrated group intervention to address both substance use and intimate partner abuse perpetration by men in substance use treatment: a feasibility randomised controlled trial
Background: Substance use is a risk factor for intimate partner abuse (IPA) perpetration. Delivering perpetrator
interventions concurrently with substance use treatment shows promise.
Methods: The feasibility of conducting an efficacy and cost-effectiveness trial of the ADVANCE 16-week
intervention to reduce IPA by men in substance use treatment was explored. A multicentre, parallel group
individually randomised controlled feasibility trial and formative evaluation was conducted. Over three temporal
cycles, 104 men who had perpetrated IPA towards a female (ex) partner in the past year were randomly allocated
to receive the ADVANCE intervention + substance use treatment as usual (TAU) (n = 54) or TAU only (n = 50) and
assessed 16-weeks post-randomisation. Participants’ (ex) partners were offered support and 27 provided outcome
data. Thirty-one staff and 12 men who attended the intervention participated in focus groups or interviews that
were analysed using the framework approach. Pre-specified criteria assessed the feasibility of progression to a
definitive trial: 1) ≥ 60% of eligible male participants recruited; 2) intervention acceptable to staff and male
participants; 3) ≥ 70% of participants followed-up and 4) levels of substance use and 5) IPA perpetrated by men in
the intervention arm did not increase from average baseline level at 16-weeks post-randomisation.
Results: 70.7% (104/147) of eligible men were recruited. The formative evaluation confirmed the intervention’s
acceptability. Therapeutic alliance and session satisfaction were rated highly. The overall median rate of intervention
session attendance (of 14 compulsory sessions) was 28.6% (range 14.3–64.3% by the third cycle). 49.0% (51/104) of
men and 63.0% (17/27) of their (ex) partners were followed-up 16-weeks post-randomisation. This increased to
100% of men and women by cycle three. At follow-up, neither substance use nor IPA perpetration had worsened
for men in the intervention arm.
Conclusions: It was feasible to deliver the ADVANCE intervention in substance use treatment services, although it
proved difficult to collect data from female (ex)partners. While some progression criteria were met, others were not,
although improvements were demonstrated by the third cycle. Lessons learned will be implemented into the study
design for a definitive trial of the ADVANCE intervention
Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment
We present field observations made in June 2011 downwind of Dallas-Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H2SO4) production. Zero-dimensional model calculations show that sCI from biogenic volatile organic compounds composed the majority of the sCIs. The main uncertainty associated with an evaluation of H2SO4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO2 along with systematic discrepancies in experimentally derived reaction rates between other sCIs and SO2 and water vapor. In general, the maximum of H2SO4 production from the sCI channel is found in the late afternoon as ozone increases toward the late afternoon. The sCI channel, however, contributes minor H2SO4 production compared with the conventional OH channel in the mid-day. Finally, the production and the loss rates of H2SO4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H2SO4 loss rates compared with H2SO4 production rates. However, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H2SO4. The results suggest that the recommended coefficient for the H2O surface may not be suitable for this relatively dry environment
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