Letters to the Editor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66389/1/j.1600-0447.1989.tb03017.x.pd

Observation of Skewed Electromagnetic Wakefields in an Asymmetric Structure Driven by Flat Electron Bunches

Relativistic charged-particle beams which generate intense longitudinal fields in accelerating structures also inherently couple to transverse modes. The effects of this coupling may lead to beam break-up instability, and thus must be countered to preserve beam quality in applications such as linear colliders. Beams with highly asymmetric transverse sizes (flat-beams) have been shown to suppress the initial instability in slab-symmetric structures. However, as the coupling to transverse modes remains, this solution serves only to delay instability. In order to understand the hazards of transverse coupling in such a case, we describe here an experiment characterizing the transverse effects on a flat-beam, traversing near a planar dielectric lined structure. The measurements reveal the emergence of a previously unobserved skew-quadrupole-like interaction when the beam is canted transversely, which is not present when the flat-beam travels parallel to the dielectric surface. We deploy a multipole field fitting algorithm to reconstruct the projected transverse wakefields from the data. We generate the effective kick vector map using a simple two-particle theoretical model, with particle-in-cell simulations used to provide further insight for realistic particle distributions.Comment: Six pages, seven figures. Submitted to Physical Revie

precision control of the electron longitudinal bunch shape using an emittence-exchange beam line

We report on the experimental generation of relativistic electron bunches with a tunable longitudinal bunch shape. A longitudinal bunch-shaping (LBS) beam line, consisting of a transverse mask followed by a transverse-to-longitudinal emittance exchange (EEX) beam line, is used to tailor the longitudinal bunch shape (or current profile) of the electron bunch. The mask shapes the bunch's horizontal profile, and the EEX beam line converts it to a corresponding longitudinal profile. The Argonne wakefield accelerator rf photoinjector delivers electron bunches into a LBS beam line to generate a variety of longitudinal bunch shapes. The quality of the longitudinal bunch shape is limited by various perturbations in the exchange process. We develop a simple method, based on the incident slope of the bunch, to significantly suppress the perturbations.1162Ysciescopu

The association between mental health nursing and hospital admissions for people with serious mental illness: a protocol for a systematic review

Background: Relapse in individuals with severe mental illness (SMI) is a frequent occurrence and can add considerably to the burden of disease. As such, relapse prevention is an essential therapeutic outcome for people with SMI. Mental health nurses (MHNs) are well placed to support individuals with SMI and to prevent relapse; notwithstanding, there has been no synthesis of the evidence to date to determine whether MHNs prevent relapse in this population. Methods: Electronic databases will be systemically searched for observational studies and clinical trials that report the association between mental health nursing and the hospitalisation of persons living with an SMI. The search will be supplemented by reference checking and a search of the grey literature. The primary outcome of interest will be hospital admission rate. Screening of articles, data extraction and critical appraisal will be undertaken by two reviewers, independently, with a third reviewer consulted should disagreement occur between reviewers. The quality of studies will be assessed using the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool and the Cochrane Collaboration risk of bias tool. Depending on the number of studies and level of heterogeneity, the evidence may be synthesised using meta-analysis or narrative synthesis. Discussion: This review will explore for the first time the clinical potential of mental health nursing in preventing relapse in persons with SMI. The findings of this review will serve to inform future research and education in this area. The evidence may also help inform future policy, including decisions regarding future mental health workforce development and planning

Principals' reports of adults' alcohol use in Australian secondary schools

Background - Schools provide opportunities for parents and the wider community to connect and support the physical and emotional wellbeing of their children. Schools therefore have the potential to play a role in the socialisation of alcohol use through school policies and practices regarding consumption of alcohol by adults at school events in the presence of children. Methods - This survey was undertaken to a) compare the extent to which alcohol is used at secondary school events, when children are present, in the states of New South Wales (NSW) and Victoria (VIC), Australia; b) describe principals’ level of agreement with these practices; c) their awareness of state policies on this issue; and d) the predictors of such events. A random sample of secondary schools, stratified to represent metropolitan and non-metropolitan schools were invited to participate. Bivariate and multivariate analysis were conducted with p values < 0.05 considered significant. Results - A total of 241 (43 %) schools consented to participate in the study. Fifteen percent of participating NSW schools and 57 % of VIC schools held at least one event in which alcohol was consumed by adults in the presence of children in the year before the survey. Of the 100 reported events, 78 % were Year 12 graduation dinners, and 18 % were debutante balls. Compared to NSW principals, VIC principals were significantly more likely to agree with the use of alcohol at these events; significantly less likely to be aware of their state education department policy on this issue; have a policy at their own school or support policy that prohibits alcohol use at such events; and less likely to report having enough Information to make decisions about this. Conclusions - There is a growing focus on adults’ use of alcohol at school events when children are present. Schools can play an important role in educating and socialising children about alcohol via both the curriculum and policies regarding adults’ alcohol use at school events. Findings from this study suggest education department and school-based policies that prohibit or restrict the use of alcohol, are significant predictors of adults’ alcohol use at school events when children are present

Novel implementation research designs for scaling up global mental health care: overcoming translational challenges to address the world’s leading cause of disability

Despite established knowledge that Low and Middle Income Countries (LMICs) bear the majority of the world’s burden of mental disorders, and more than a decade of efficacy research showing that the most common disorders, such as depression and anxiety, can be treated using readily available local personnel in LMICs to apply evidence-based treatments, there remains a massive mental health treatment gap, such that 75 % of those in LMICs never receive care. Here, we discuss the use of a new type of implementation science study design, the effectiveness-implementation hybrids, to speed the translation and scale up of mental health care in LMICs. We use our current study of Interpersonal Psychotherapy (IPT) delivered by local personnel for depression and trauma-related disorders among HIV+ women in Kenya as an example of effectiveness-implementation hybrid design for mental health services research in LMICs

Clinical characteristics associated with the prescribing of SSRI medication in adolescents with major unipolar depression.

Unipolar major depressions (MD) emerge markedly during adolescence. National Institute for Health and Care Excellence (NICE) UK recommends psychological therapies, with accompanying selective serotonin reuptake inhibitors (SSRIs) prescribed in severe cases only. Here, we seek to determine the extent and rationale of SSRI prescribing in adolescent MD before entering a randomised clinical trial. SSRI prescribing, together with their clinical characteristics was determined in 465 adolescent patients with MD prior to receiving a standardised psychological therapy as part of the Improving mood with psychoanalytic and cognitive therapies (IMPACT) clinical trial. Overall, 88 (19 %) had been prescribed antidepressants prior to psychological treatment. The clinical correlates varied by gender: respectively, depression severity in boys and self-harming behaviours in girls. Prescribing also differed between clinical research centres. Medical practitioners consider severity of depression in boys as an indicator for antidepressant prescribing. Self-injury in girls appears to be utilised as a prescribing aid which is inconsistent with past and current revised UK NICE guidelines.RCT Study supported by a grant to IMG (Chief Investigator) from the NIHR-HTA (trial number ISRCTN83033550, grant number 06/05/01).This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Springer

Do adults in contact with Australia's public sector mental health services get better?

This paper describes the outcomes of episodes of care for adults in public sector mental health services across Australia, with a view to informing the debate on service quality. Health of the Nation Outcome Scales (HoNOS) change scores and effect sizes were calculated for 14,659 acute inpatient episodes and 23,692 community episodes. The results showed that people in contact with public sector mental health services generally do get better, although the magnitude of improvement depends on the setting and episode type. This confirmatory finding is particularly positive, given current community concerns about the quality and effectiveness of mental health services

Addressing challenges in the production and analysis of illumina sequencing data

Advances in DNA sequencing technologies have made it possible to generate large amounts of sequence data very rapidly and at substantially lower cost than capillary sequencing. These new technologies have specific characteristics and limitations that require either consideration during project design, or which must be addressed during data analysis. Specialist skills, both at the laboratory and the computational stages of project design and analysis, are crucial to the generation of high quality data from these new platforms. The Illumina sequencers (including the Genome Analyzers I/II/IIe/IIx and the new HiScan and HiSeq) represent a widely used platform providing parallel readout of several hundred million immobilized sequences using fluorescent-dye reversible-terminator chemistry. Sequencing library quality, sample handling, instrument settings and sequencing chemistry have a strong impact on sequencing run quality. The presence of adapter chimeras and adapter sequences at the end of short-insert molecules, as well as increased error rates and short read lengths complicate many computational analyses. We discuss here some of the factors that influence the frequency and severity of these problems and provide solutions for circumventing these. Further, we present a set of general principles for good analysis practice that enable problems with sequencing runs to be identified and dealt with