343 research outputs found
Superfluid qubit systems with ring shaped optical lattices
We study an experimentally feasible qubit system employing neutral atomic
currents. Our system is based on bosonic cold atoms trapped in ring-shaped
optical lattice potentials. The lattice makes the system strictly one
dimensional and it provides the infrastructure to realize a tunable ring-ring
interaction. Our implementation combines the low decoherence rates of of
neutral cold atoms systems, overcoming single site addressing, with the
robustness of topologically protected solid state Josephson flux qubits.
Characteristic fluctuations in the magnetic fields affecting Josephson junction
based flux qubits are expected to be minimized employing neutral atoms as flux
carriers. By breaking the Galilean invariance we demonstrate how atomic
currents through the lattice provide a implementation of a qubit. This is
realized either by artificially creating a phase slip in a single ring, or by
tunnel coupling of two homogeneous ring lattices. The single qubit
infrastructure is experimentally investigated with tailored optical potentials.
Indeed, we have experimentally realized scaled ring-lattice potentials that
could host, in principle, of such ring-qubits, arranged in a stack
configuration, along the laser beam propagation axis.
An experimentally viable scheme of the two-ring-qubit is discussed, as well.
Based on our analysis, we provide protocols to initialize, address, and
read-out the qubit.Comment: 14 revtex4-1 pages, 7 figs; to be published in Scientific Report
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Barebacking and sexual position
Bareback sex continues to fuel the HIV epidemic among men who have sex with men but despite the fact that much academic attention has been focused on the sexual behaviour of this population few authors have considered the significance of sexual position. In order to explore this relatively under-examined factor, interviews were conducted with 13 HIV-negative and unknown status gay men who had recently engaged in bareback sex. Using Interpretative Phenomenological Analysis and through the lens of sexual position, the findings were organised across three super-ordinal themes. There were some areas in which there was little difference between the men’s experiences of engaging in bareback as tops or bottoms (for instance, how participants connected with barebacking partners). In other areas, however, there were clear differences in men’s experiences according to sexual position, particularly in the interpersonal dynamic between tops and bottoms during bareback sex encounters, which it is argued were acted out in accordance with a barebacking ‘sexual script’. There were further differences by position in how individuals overcame ‘cognitive dissonance’ by invoking strategies to make their engagement in bareback sex safer and in the meanings men ascribed to bareback sex and semen exchange. These findings provide valuable insights for those working with MSM around HIV prevention
Willingness to participate in future HIV prevention studies among gay and bisexual men in Scotland, UK: a challenge for intervention trials
This article examines willingness to participate in future HIV prevention research among gay and bisexual men in Scotland, UK. Anonymous, self-complete questionnaires and Orasure Gäó oral fluid samples were collected in commercial gay venues. 1,320 men were eligible for inclusion. 78.2% reported willingness to participate in future HIV prevention research; 64.6% for an HIV vaccine, 57.4% for a behaviour change study, and 53.0% for a rectal microbicide. In multivariate analysis, for HIV vaccine research, greater age, minority ethnicity, and not providing an oral fluid sample were associated with lower willingness; heterosexual orientation and not providing an oral fluid sample were for microbicides; higher education and greater HIV treatment optimism were for behaviour change. STI testing remained associated with being more willing to participate in microbicide research and frequent gay scene use remained associated with being more willing to participate in behaviour change research. Having an STI in the past 12 months remained significantly associated with being willing to participate in all three study types. There were no associations between sexual risk behaviour and willingness. Although most men expressed willingness to participate in future research, recruitment of high-risk men, who have the potential to benefit most, is likely to be more challenging
The Effect of Partner Sex: Nondisclosure of HIV Status to Male and Female Partners Among Men who Have Sex with Men and Women (MSMW)
A common concern within HIV prevention is that HIV positive MSMW do not disclose their HIV status to female partners who are thus at increased risk for HIV infection. The present study uses unique data to examine whether MSMW disclose more often to male rather than female partners. Data were collected on most recent male and/or female primary partner and four most recent casual partners from 150 MSMW (50 African American, 50 Latino, 50 White). MSMW reported on 590 partners (31% female; 69% male). Disclosure was coded as disclosure before sex, disclosure after sex, or nondisclosure. A series of multinomial logistic regressions with partners clustered within respondents were conducted to evaluate effects of respondent characteristics and partner characteristics on timing of disclosure. In bivariate and multivariate analyses there were no significant differences in odds of disclosure to male and female partners before or after sex. Although MSMW were substantially less likely to disclose to HIV negative partners before sex compared to HIV positive partners regardless of sex, when we fully interacted the multivariate model by partner sex, the odds of disclosure to HIV negative male partners compared to HIV positive male partners before sex were significantly higher than the odds of disclosure to HIV negative female partners compared to HIV positive female partners. Patterns of mutual nondisclosure and nonreciprocal disclosure were observed with both primary and casual partners. The paper makes additional methodological contributions to the measurement and analysis of disclosure
Use of community treatment orders and their outcomes: an observational study
Background
Community treatment orders are widely used in England. It is unclear whether their use varies between patients, places and services, or if they are associated with better patient outcomes.
Objectives
To examine variation in the use of community treatment orders and their associations with patient outcomes and health-care costs.
Design
Secondary analysis using multilevel statistical modelling.
Setting
England, including 61 NHS mental health provider trusts.
Participants
A total of 69,832 patients eligible to be subject to a community treatment order.
Main outcome measures
Use of community treatment orders and time subject to community treatment order; re-admission and total time in hospital after the start of a community treatment order; and mortality.
Data sources
The primary data source was the Mental Health Services Data Set. Mental Health Services Data Set data were linked to mortality records and local area deprivation statistics for England.
Results
There was significant variation in community treatment order use between patients, provider trusts and local areas. Most variation arose from substantially different practice in a small number of providers. Community treatment order patients were more likely to be in the ‘severe psychotic’ care cluster grouping, male or black. There was also significant variation between service providers and local areas in the time patients remained on community treatment orders. Although slightly more community treatment order patients were re-admitted than non-community treatment order patients during the study period (36.9% vs. 35.6%), there was no significant difference in time to first re-admission (around 32 months on average for both). There was some evidence that the rate of re-admission differed between community treatment order and non-community treatment order patients according to care cluster grouping. Community treatment order patients spent 7.5 days longer, on average, in admission than non-community treatment order patients over the study period. This difference remained when other patient and local area characteristics were taken into account. There was no evidence of significant variation between service providers in the effect of community treatment order on total time in admission. Community treatment order patients were less likely to die than non-community treatment order patients, after taking account of other patient and local area characteristics (odds ratio 0.69, 95% credible interval 0.60 to 0.81).
Limitations
Confounding by indication and potential bias arising from missing data within the Mental Health Services Data Set. Data quality issues precluded inclusion of patients who were subject to community treatment orders more than once.
Conclusions
Community treatment order use varied between patients, provider trusts and local areas. Community treatment order use was not associated with shorter time to re-admission or reduced time in hospital to a statistically significant degree. We found no evidence that the effectiveness of community treatment orders varied to a significant degree between provider trusts, nor that community treatment orders were associated with reduced mental health treatment costs. Our findings support the view that community treatment orders in England are not effective in reducing future admissions or time spent in hospital. We provide preliminary evidence of an association between community treatment order use and reduced rate of death.
Future work
These findings need to be replicated among patients who are subject to community treatment order more than once. The association between community treatment order use and reduced mortality requires further investigation.
Study registration
The study was approved by the University of Warwick’s Biomedical and Scientific Research Ethics Committee (REGO-2015-1623).
Funding
This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 9. See the NIHR Journals Library website for further project information
Understanding increasing rates of psychiatric hospital detentions in England : development and preliminary testing of an explanatory model
Background
The steep rise in the rate of psychiatric hospital detentions in England is poorly understood.
Aims
To identify explanations for the rise in detentions in England since 1983; to test their plausibility and support from evidence; to develop an explanatory model for the rise in detentions.
Method
Hypotheses to explain the rise in detentions were identified from previous literature and stakeholder consultation. We explored associations between national indicators for potential explanatory variables and detention rates in an ecological study. Relevant research was scoped and the plausibility of each hypothesis was rated. Finally, a logic model was developed to illustrate likely contributory factors and pathways to the increase in detentions.
Results
Seventeen hypotheses related to social, service, legal and data-quality factors. Hypotheses supported by available evidence were: changes in legal approaches to patients without decision-making capacity but not actively objecting to admission; demographic changes; increasing psychiatric morbidity. Reductions in the availability or quality of community mental health services and changes in police practice may have contributed to the rise in detentions. Hypothesised factors not supported by evidence were: changes in community crisis care, compulsory community treatment and prescribing practice. Evidence was ambiguous or lacking for other explanations, including the impact of austerity measures and reductions in National Health Service in-patient bed numbers.
Conclusions
Better data are needed about the characteristics and service contexts of those detained. Our logic model highlights likely contributory factors to the rise in detentions in England, priorities for future research and potential policy targets for reducing detentions
Concerns about the use of polygenic embryo screening for psychiatric and cognitive traits
Private companies have begun offering services to allow parents undergoing in-vitro fertilisation to screen embryos for genetic risk of complex diseases, including psychiatric disorders. This procedure, called polygenic embryo screening, raises several difficult scientific and ethical issues, as discussed in this Personal View. Polygenic embryo screening depends on the statistical properties of polygenic risk scores, which are complex and not well studied in the context of this proposed clinical application. The clinical, social, and ethical implications of polygenic embryo screening have barely been discussed among relevant stakeholders. To our knowledge, the International Society of Psychiatric Genetics is the first professional biomedical organisation to issue a statement regarding polygenic embryo screening. For the reasons discussed in this Personal View, the Society urges caution and calls for additional research and oversight on the use of polygenic embryo screening
Efficacy of Structural-Level Condom Distribution Interventions: A Meta-Analysis of U.S. and International Studies, 1998–2007
This systematic review examines the overall efficacy of U.S. and international-based structural-level condom distribution interventions (SLCDIs) on HIV risk behaviors and STIs and identifies factors associated with intervention efficacy. A comprehensive literature search of studies published from January 1988 through September 2007 yielded 21 relevant studies. Significant intervention effects were found for the following outcomes: condom use, condom acquisition/condom carrying, delayed sexual initiation among youth, and reduced incident STIs. The stratified analyses for condom use indicated that interventions were efficacious for various groups (e.g., youth, adults, males, commercial sex workers, clinic populations, and populations in areas with high STI incidence). Interventions increasing the availability of or accessibility to condoms or including additional individual, small-group or community-level components along with condom distribution were shown to be efficacious in increasing condom use behaviors. This review suggests that SLCDIs provide an efficacious means of HIV/STI prevention
Effects of ethnic density on the risk of compulsory psychiatric admission for individuals attending secondary care mental health services: evidence from a large-scale study in England
Background
Black, Asian and minority ethnicity groups may experience better health outcomes when living in areas of high own-group ethnic density – the so-called ‘ethnic density’ hypothesis. We tested this hypothesis for the treatment outcome of compulsory admission.
Methods
Data from the 2010–2011 Mental Health Minimum Dataset (N = 1 053 617) was linked to the 2011 Census and 2010 Index of Multiple Deprivation. Own-group ethnic density was calculated by dividing the number of residents per ethnic group for each lower layer super output area (LSOA) in the Census by the LSOA total population. Multilevel modelling estimated the effect of own-group ethnic density on the risk of compulsory admission by ethnic group (White British, White other, Black, Asian and mixed), accounting for patient characteristics (age and gender), area-level deprivation and population density.
Results
Asian and White British patients experienced a reduced risk of compulsory admission when living in the areas of high own-group ethnic density [odds ratios (OR) 0.97, 95% credible interval (CI) 0.95–0.99 and 0.94, 95% CI 0.93–0.95, respectively], whereas White minority patients were at increased risk when living in neighbourhoods of higher own-group ethnic concentration (OR 1.18, 95% CI 1.11–1.26). Higher levels of own-group ethnic density were associated with an increased risk of compulsory admission for mixed-ethnicity patients, but only when deprivation and population density were excluded from the model. Neighbourhood-level concentration of own-group ethnicity for Black patients did not influence the risk of compulsory admission.
Conclusions
We found only minimal support for the ethnic density hypothesis for the treatment outcome of compulsory admission to under the Mental Health Act
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