Betatron radiation and emittance growth in plasma wakefield accelerators

Beam-driven plasma wakefield acceleration (PWFA) has demonstrated significant progress during the past two decades of research. The new Facility for Advanced Accelerator Experimental Tests (FACET) II, currently under construction, will provide 10 GeV electron beams with unprecedented parameters for the next generation of PWFA experiments. In the context of the FACET II facility, we present simulation results on expected betatron radiation and its potential application to diagnose emittance preservation and hosing instability in the upcoming PWFA experiments. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Producing multi-coloured bunches through beam-induced ionization injection in plasma wakefield accelerator

This paper discusses the properties of electron beams formed in plasma wakefield accelerators through ionization injection. In particular, the potential for generating a beam composed of co-located multi-colour beamlets is demonstrated in the case where the ionization is initiated by the evolving charge field of the drive beam itself. The physics of the processes of ionization and injection are explored through OSIRIS simulations. Experimental evidence showing similar features are presented from the data obtained in the E217 experiment at the FACET facility of the SLAC National Laboratory. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

The homeless and the mental health services: a Liverpool study

It is well known that there is a high prevalence of psychiatric disorder among residents in hostels for the homeless (Timms & Fry, 1989), and staff in these hostels are looking after the mental health needs of these people sometimes with little help from the institutional services. Recent studies have emphasised the plight of schizophrenia sufferers (Marshall, 1993) while other subgroups of mentally disordered homeless people have received less attention.

Acceleration of a trailing positron bunch in a plasma wakefield accelerator

High gradients of energy gain and high energy efficiency are necessary parameters for compact, cost-efficient and high-energy particle colliders. Plasma Wakefield Accelerators (PWFA) offer both, making them attractive candidates for next-generation colliders. In these devices, a charge-density plasma wave is excited by an ultra-relativistic bunch of charged particles (the drive bunch). The energy in the wave can be extracted by a second bunch (the trailing bunch), as this bunch propagates in the wake of the drive bunch. While a trailing electron bunch was accelerated in a plasma with more than a gigaelectronvolt of energy gain, accelerating a trailing positron bunch in a plasma is much more challenging as the plasma response can be asymmetric for positrons and electrons. We report the demonstration of the energy gain by a distinct trailing positron bunch in a plasma wakefield accelerator, spanning nonlinear to quasi-linear regimes, and unveil the beam loading process underlying the accelerator energy efficiency. A positron bunch is used to drive the plasma wake in the experiment, though the quasi-linear wake structure could as easily be formed by an electron bunch or a laser driver. The results thus mark the first acceleration of a distinct positron bunch in plasma-based particle accelerators.

Disruption of host-seeking behaviour by the salmon louse, Lepeophtheirus salmonis, using botanically derived repellents

The potential for developing botanically derived natural products as novel feed-through repellents for disrupting settlement of the salmon louse, Lepeophtheirus salmonis (Caligidae) upon farmed Atlantic salmon, Salmo salar, was investigated using an established laboratory vertical Y-tube behavioural bioassay for assessing copepodid behaviour. Responses to artificial sea water conditioned with the odour of salmon, or to the known salmon-derived kairomone component, α-isophorone, in admixture with selected botanical materials previously known to interfere with invertebrate arthropod host location were recorded. Materials included oils extracted from garlic, Allium sativum (Amaryllidaceae), rosemary, Rosmarinus officinalis (Lamiaceae), lavender, Lavandula angustifolia (Lamiaceae), and bog myrtle, Myrica gale (Myricaceae), and individual components (diallyl sulphide and diallyl disulphide from garlic; allyl, propyl, butyl, 4-pentenyl and 2-phenylethyl isothiocyanate from plants in the Brassica genus). Removal of attraction to salmon-conditioned water (SCW) or α-isophorone was observed when listed materials were presented at extremely low parts per trillion (ppt), that is picograms per litre or 10^-12 level. Significant masking of attraction to SCW was observed at a level of 10 ppt for diallyl disulphide and diallyl sulphide, and allyl isothiocyanate and butyl isothiocyanate. The potential of very low concentrations of masking compounds to disrupt Le. salmonis copepodid settlement on a host fish has been demonstrated in vitro.

Patient acceptability and experiences of therapeutic switching of proton pump inhibitors within the National Preferred Drugs initiative in Ireland

INTRODUCTION

A 'Preferred Drugs' initiative was introduced into Ireland in 2013. This identified a single recommended drug to be prescribed to patients requiring treatment from a particular class of drugs.

AIMS

This study investigates how patients on established proton pump inhibitor (PPI) therapy experienced the therapeutic switching of their medication to the 'preferred drug', and the extent to which they regarded it as an acceptable practice.

METHODS

The experiences of 61 patients on established proton pump inhibitor (PPI) therapy were sought before and after their drug was switched to the 'preferred drug'.

RESULTS

Eighty per cent of patients were happy to switch medications. When asked for their opinions on medications in general, 71% felt doctors should prescribe the least expensive medication, 84% agreed that all licensed medications were safe while 67% felt their GP changing medication for cost reasons was safe. After 8 weeks, 20% of patients had switched back to their old PPI. When asked how they felt about their medication change, 74% felt happy or pleased.

CONCLUSIONS

The majority of patients in our study were satisfied to have their medication switched. However, prescribers should be mindful that 1 in 5 patients encountered problems as a result of the switching process.

Are Adults Attending GPs Able to Check Their Own Weight?

Studies have shown self-weighing behaviour is associated with weight loss and maintenance of previous losses. In this cross-sectional survey of 151 patients, 98 (65.0%) participants were overweight or obese, and 59 (31.9%) participants did not self-weigh. Healthcare teams should advise patients on weighing practices to control obesity.

Screening for Chlamydia is acceptable and feasible during Cervical Screening in General Practice

The incidence of Chlamydia trachomatis (CT) & Neisseria gonorrhoeae (NG) are rising in Ireland. Both are often undiagnosed and may cause infertility amongst other complications. CT/NG screening is not routinely offered during cervical cancer screening. This study aimed to ascertain the feasibility and acceptability of screening for CT/NG at time of smear and to measure the diagnostic yield. Screening was offered to women aged 25-40 years attending four participating general practices as part of Cervical Check. A retrospective review of the three months preceding the study period, indicated that out of 138 smears, CT/NG testing was performed in 10 (7%) of cases. 236 (93%) patients consented to screening for CT/NG. The detection rate for Chlamydia was 6 (2.4%), with no positive results for NG. Feedback from patients was positive. Interestingly, 42 (18%) of participants who completed the questionnaire believed STI screening was already part of the routine smear.

Insights and Concerns of Patients and GPs Regarding Introduction of Universal Health Insurance in Ireland

The implementation of a universal health insurance (UHI) model is a key political policy in Ireland. The objective here was to determine the understanding of general practitioners (GPs) and patients regarding UHI, its implementation and impact on both sets of stakeholders. Postal questionnaire to GPs, and opportunistic survey sampling of patients in two different GP practices were carried out. Response rates were 92.5% (patients) and 78% (GPs). 79.4% of patients (n = 418) and 96.7% of GPs (n = 149) have a 'poor' understanding of how UHI will be implemented. 89% (n = 493) of patients and 98.7% (n = 153) of GPs feel government communication about UHI has been 'poor'. 98.1% of GPs (n = 152) and 77.3% of patients (n = 383) are not confident that 'UHI will be ready for implementation by 2015'. Neither stakeholder group is confident in the government's ability to deliver UHI within the given timeframe. There is a lack of knowledge and consultation on proposals for its implementation.

Is primary prevention of childhood obesity by education at 13-month immunisations feasible and acceptable? Results from a general practice based pilot study

Abstract Prevalence of childhood overweight and obesity remains high in Ireland. In this study an intervention conducted within primary care was evaluated. This involved a structured discussion with parents at the 13 month immunisations with their general practitioner (GP), including measuring weight of the toddler and parental education regarding healthy nutrition and physical activity for their toddler. There was a telephone follow-up interview with parents three months later assessing change in toddler diet/lifestyle. Endpoints assessed included parents' reports of specific lifestyle parameters with regard to the toddler and parental assessment of the usefulness of the intervention. 39 toddlers were studied. Most lifestyle parameters had improved at follow up. Reported fruit and vegetable intake of more than 4 portions per day increased from 20.5% of toddlers at baseline 28.6% at follow up. The number of toddlers abstaining from unhealthy snacks increased from 15.4% to 21.4%. Television watching of more than 2 hours daily decreased from 12.8% to 0%. Supervised exercise of more than thirty minutes per day increased from 69.2% to 89.3%. The majority of parents reported at follow up that they found the intervention acceptable (100%, n = 28) and useful (79%, n = 22).

Planar-dielectric-wakefield accelerator structure using Bragg-reflector boundaries

We report experimental measurements of narrow-band, single-mode excitation, and drive beam energy modulation, in a dielectric wakefield accelerating structure with planar geometry and Bragg-reflector boundaries. A short, relativistic electron beam (∼1  ps) with moderate charge (∼100  pC) is used to drive the wakefields in the structure. The fundamental mode of the structure is reinforced by constructive interference in the alternating dielectric layers at the boundary, and is characterized by the spectral analysis of the emitted coherent Cherenkov radiation signal. Data analysis shows a narrow-band peak at 210 GHz corresponding to the fundamental mode of the structure. Simulations in both 2D and 3D provide insight into the propagating fields and reproduction of the electron beams dynamics observables and emitted radiation characteristics.

Are we ready to "think ahead"? Acceptability study using an innovative end of life planning tool

This is a cross sectional study in 5 GP Training Practices, sample size 100 clinically stable patients, attending for routine care. Purpose of the study was explained and informed written consent was sought. Participants were provided with 'Think Ahead,' an innovative end of life planning tool, devised by The Forum on The End of Life, based on best international practice, presented in a questionnaire format, detailing main decision centres relevant in end of life planning. Participants completed telephone surveys at 1 and 3 weeks, ascertaining their experience with 'Think Ahead;' 92/100 completed both surveys. Results indicate high levels of acceptability and positive experience for most participants. A majority (63%) indicated 'no difficulty' in completing 'Think Ahead;' 74% indicated reported they did not find completing the folder to cause upset; 87% indicated they felt the folder should be more widely available, and 68% indicated they felt 'Think Ahead' would be of general interest. The study was effective in encouraging discussion on end of life issues with family (83%) with 49% indicating they had done so in detail, and 34% indicating having 'done so somewhat,' having read 'Think Ahead; 27% indicated aspects of it were upsetting. Results will be used to inform further development of the tool. General Practice consulting is a suitable context in which to systematically present 'Think Ahead.'

Delayed prescribing of antibiotics for respiratory tract infections: use of information leaflets

The appropriate prescribing of antibiotics is a challenge in primary care12. We performed an interventional trial to determine if providing an information leaflet on antibiotics with a delayed antibiotic prescription influenced the patient's decision to use the antibiotic for a respiratory tract infection (RTI). The control group (n = 69) where given a delayed prescription and the intervention group (n = 46) were given an information leaflet on antibiotics with the delayed prescription. In the control group, 72% (n = 50) of patients indicated they subsequently used the antibiotic, and in the intervention group, 43%(n = 20) indicated they used the antibiotic, this difference was statistically significant (p = 0.0018.) The key conclusion of this study is that delayed prescriptions should be issued with an appropriate information sheet.

Chronic disease management in patients attending Irish General Practice training practices

Complexity and workload for patients with chronic diseases in General Practice are poorly understood. Government policy envisages moving workload into primary care. Data was obtained from a GP delivered survey (58 GPs/33 practices) of 160 patients with one or more chronic diseases, and by concurrently extracting data from the patients electronic medical record. Care is physician intensive (average number GP visits 9.2 pa), with limited input from Practice Nurses (1.62 visits pa). Care co-ordination is significant, given complex co morbidity, polypharmacy (average number of medications per patient = 6.8), and numbers of OPDs attended (3.8). Over a quarter of patients (51/160 (27%)) required assistance attending their GP; 60 (31%) self rated their health as fair/poor. Patients are positively disposed towards transfer of care to General Practice. This study provides baseline data on complexity/workload in care delivered in GP Training practices, before implementation of change.

Establishing a general practitioner led minor injury service: mixed methods evaluation at 10 months with an emphasis on use of radiology by GPs in the out-of-hours setting

AIMS AND METHODS

A mixed methods study was conducted to evaluate a recently established general practitioner (GP) led minor injury (MI) service; it included a patient feedback study, a qualitative enquiry into the experience of the MI GPs, and analysis of use of radiology.

RESULTS

Forty-nine (81.6 %) patients surveyed were seen in 30 min or less. Forty-five (75 %) felt that the quality of the service was excellent/very good. Twenty-seven (45 %) responders felt that the X-ray service was expensive; 49 (81.6 %) patients said that they would be happy to use the service again. 271 X-rays were taken (137, 50.55 % upper limb, 95, 35.06 % lower limb, 18, 6.64 % CXR). One hundred and ninety-four (73.48 %) patients were self-financing. There was an 86.72 % (235/271) concordance between GP/radiologist findings. Issues elaborated by MI GPs at the focus group included secondary care/hospital interaction, patients' experience, professional fulfilment, competence concerns, finances, and interest in educational resources; they were unanimous in maintaining the service at 10 months.

CONCLUSIONS

This study demonstrates a positive experience by patients, and conservative evaluation of X-rays by GPs.

Dielectric wakefield acceleration of a relativistic electron beam in a slab-symmetric dielectric lined waveguide

We report first evidence of wakefield acceleration of a relativistic electron beam in a dielectric-lined slab-symmetric structure. The high energy tail of a ∼60  MeV electron beam was accelerated by ∼150  keV in a 2 cm-long, slab-symmetric SiO2 waveguide, with the acceleration or deceleration clearly visible due to the use of a beam with a bifurcated longitudinal distribution that serves to approximate a driver-witness beam pair. This split-bunch distribution is verified by longitudinal reconstruction analysis of the emitted coherent transition radiation. The dielectric waveguide structure is further characterized by spectral analysis of the emitted coherent Cherenkov radiation at THz frequencies, from a single electron bunch, and from a relativistic bunch train with spacing selectively tuned to the second longitudinal mode (TM02). Start-to-end simulation results reproduce aspects of the electron beam bifurcation dynamics, emitted THz radiation properties, and the observation of acceleration in the dielectric-lined, slab-symmetric waveguide.

Chronic disease management in general practice: results from a national study

The aim of this study was to provide baseline data on chronic disease management (CDM) provision in Irish general practice (GP). The survey instrument was previously used in a study of primary care physicians in 11 countries, thus allowing international comparisons. The response rate was 72% (380/527).The majority of GPs (240/380; 63%) reported significant changes are needed in our health care system to make CDM work better. Small numbers of routine clinical audits are being performed (95/380; 25%). Irish GPs use evidence based guidelines for treatment of diabetes (267/380; 71%), asthma / COPD (279/380; 74%) and hypertension (297/380; 79%), to the same extent as international counterparts. Barriers to delivering chronic care include increased workload (379/380; 99%), lack of appropriate funding (286/380; 76%), with GPs interested in targeted payments (244/380; 68%). This study provides baseline data to assess future changes in CDM.

Childhood obesity: parents fail to recognise, general practitioners fail to act

General Practitioners (GPs) have an important role to play in recognition of and intervention against childhood obesity in Ireland. Data were collected prospectively on a cohort of children aged 4-14 and their parents (n = 101 pairs) who attended consecutively to a semi-rural group general practice. Parents estimated their child's weight status. Actual weight status was determined for both parent and child using the United States Centres' for Disease Control's BMI-for-age references. 15 (14.9%) of the children and 49 (51.6%) of the parents were overweight or obese. While 71 (95.5%) of normal weight status children were correctly identified, parents showed poor concordance in identifying their children as overweight 2 (18.2%) or obese 0 (0%). BMI was only evidently recorded in the clinical records of 1 out of 15 cases of overweight children identified. With parents failing to recognise childhood obesity, GPs have a responsibility in tackling this problem at a family level.

Novel radio-frequency gun structures for ultrafast relativistic electron diffraction

Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at the atomic scale with sub-100 fs temporal resolution in a single shot. We analyze the limitations on the temporal and spatial resolution of this technique considering the operating parameters of a standard 1.6 cell RF gun (which is the RF photoinjector used for the first experimental tests of relativistic UED at Stanford Linear Accelerator Center; University of California, Los Angeles; Brookhaven National Laboratory), and study the possibility of employing novel RF structures to circumvent some of these limits.

Etonogestrel implant as a contraceptive choice; patient acceptability and adverse effect profile in a general practice setting

The aim of this study was to evaluate the experience of a cohort of patients utilizing the etonogestrel implant (Implanon) in an Irish General Practice setting. This study involved a survey administered as a telephone questionnaire, to a cohort of women (n=75) who opted to use the etonogestrel implant. 53% reported problems with the implant post insertion, the commonest problem being irregular bleeding in 22% cases. Early removals were documented in 28% cases, of which, 29%, were caused by irregular bleeding. Based on this study, it is evident that women have high expectations of the implant, and counselling about what they can expect during use is important in order to avoid unreasonable expectations. This study also demonstrates that the use of the etonogestrel implant is a valuable contraceptive option, which can be successfully delivered in a GP setting, for both patients of the practice as well as patients referred by colleagues locally.

Amplified fragment length polymorphism reveals genomic variability among Mycobacterium avium subsp. paratuberculosis isolates

Ninety-six primer sets were used for amplified fragment length polymorphism (AFLP) to characterize the genomes of 20 Mycobacterium avium subsp. paratuberculosis field isolates, 1 American Type Culture Collection (ATCC) M. avium subsp. paratuberculosis isolate (ATCC 19698), and 2 M. avium subsp. avium isolates (ATCC 35716 and Mac 104). AFLP analysis revealed a high degree of genomic polymorphism among M. avium subsp. paratuberculosis isolates that may be used to establish diagnostic patterns useful for the epidemiological tracking of M. avium subsp. paratuberculosis isolates. Four M. avium subsp. paratuberculosis-polymorphic regions revealed by AFLP were cloned and sequenced. Primers were generated internal to these regions for use in PCR analysis and applied to the M. avium subsp. paratuberculosis field isolates. An appropriate PCR product was obtained in 79 of 80 reactions, while the M. avium subsp. avium isolates failed to act as templates for PCR amplification in seven of eight reactions. This work revealed the presence of extensive polymorphisms in the genomes of M. avium subsp. paratuberculosis and M. avium subsp. avium, many of which are based on deletions. Of the M. avium subsp. paratuberculosis-specific sequences studied, one revealed a 5,145-bp region with no homologue in the M. avium subsp. avium genome. Within this region are genes responsible for integrase-recombinase function. Three additional M. avium subsp. paratuberculosis-polymorphic regions were cloned, revealing a number of housekeeping genes; all were evaluated for their diagnostic and epidemiological value.

Enhanced sandfly attraction to Leishmania-infected hosts

We report that hamsters infected with Leishmania infantum are more attractive to female sandflies in bioassays. Entrained odours from infected animals were shown by gas chromatography to contain peaks absent from uninfected individuals. Implications of enhanced transmission, potential for developing novel diagnoses and the significance to epidemiological models are discussed.

Post-traumatic stress disorder: A review for the general psychiatrist

Post-traumatic stress disorder affects about one in every hundred of the population at any particular time. Aetiological factors include genetics, personality, a background of psychiatric problems, the personal meaning of the traumatic event, issues of proximity or intensity, childhood abuse, and the initial emotional response to stress. Many precipitants are known, ranging from combat through rape or torture to difficult parturition. Core symptoms are reflective of the traumatic precipitant. Prolonged symptoms are associated with prior psychiatric or physical problems, poverty, repeated assault, alcohol or drug abuse, and cultural factors. Co-morbidity is high, especially for depression, alcohol and drug misuse. Reduced hippocampal volume, corticosteroid abnormalities, and adrenergic overactivity have been described. The use of official criteria and specific measuring instruments help in differential diagnosis. Management needs to be tailored to the needs of the individual and the stage of the disorder, and includes psychotherapy, antidepressants, and the newer eye-movement desensitization and reprocessing approach. ( Int J Psych Clin Pract 2001; 5:11-18).

Disulfiram revisited

Disulfiram can be important in helping motivated alcoholics to remain abstinent. Prescribers should be aware of disulfiram's toxicity, and how to recognize and manage reactions. A number of other agents are available to help alcoholics remain sober, although these do not necessarily obviate use of disulfiram. Also, disulfiram may have a wider role in the management of the addictions, e.g. in cocaine use.

Self-harm and unemployment

Unemployment is an important variable in both suicide and attempted suicide, acts that are themselves woven from a complex tapestry of interacting factors. The manner in which being unemployed leads to acts of self-destruction can often be better understood from detailed case histories than from the cold fruits of epidemiological research.

The influence of hospital-based prescribers on prescribing in general practice

OBJECTIVE

To document the influence of hospital prescribers on prescribing in general practice.

DESIGN AND PARTICIPANTS

Five percent of members of the Irish College of General Practitioners (n = 92) prospectively recorded 40 consecutive prescriptions.

INTERVENTIONS

The name, dose and amount of medicine prescribed as well as the indication for therapy, details of their practice, distribution of private/GMS patients, and the number of years since qualification were recorded. The cost of individual prescriptions was calculated based on the ingredient cost and the number of days of treatment. This was subsequently correlated with the origin of the prescription. Each prescription was classified as either new or repeat.

MAIN OUTCOME MEASURES AND RESULTS

Of 3286 prescriptions, 69% were for the state-supported General Medical Services (GMS) patients and 31% for private patients. Repeat prescriptions constituted 51%; 49% were new prescriptions. While hospital doctors initiated only 8% of private prescriptions, they initiated 38% of GMS prescriptions, particularly repeat prescriptions and those for cardiovascular, hormonal and centrally-acting agents. Prescriptions for anti-infectives, oral contraceptives, dermatological preparations and musculoskeletal drugs were mostly initiated in general practice. The median cost for hospital-initiated GMS prescriptions (5.93 Pounds) was greater than the cost of general practitioner (GP)-initiated prescriptions (3.49 Pounds; p < 0.01). Prescriptions from GPs who were qualified for less than 10 years and those with a mixed urban and rural practice were less costly (p < 0.05) than those issued by doctors qualified for over 10 years or working predominantly in an urban or rural area. These findings may also reflect differences in patient population, morbidity and demography.

CONCLUSIONS

Our study indicates that hospital-initiated prescriptions are responsible for a significant proportion, both in volume and cost of GP prescribing.

Low rate of generic prescribing in the Republic of Ireland compared to England and Northern Ireland: prescribers' concerns

We compared the level of generic prescribing in the Republic of Ireland, Northern Ireland and England and surveyed the views of Irish College of General Practitioners members. In 1993, generic drugs (pure generics and branded generics together) comprised 17.4% of total dispensing in the General Medical Services Scheme, significantly less than Northern Ireland or England where pure generics alone comprised 25% and 38% respectively of total dispensing in the National Health Services. General practitioners accurately self-estimated their level of generic prescribing but are concerned about the reliability/quality of generic products on the market, possible legal liabilities associated with their use and the fact that pharmacists may legally dispense more expensive proprietary preparations in the case of private prescriptions written generically. Prescribers need reassurance regarding legal and quality assurance aspects of generic prescribing if the level of generic drug use is to increase.

A review of Huntington's disease

Huntington's disease is an autosomal dominant neuropsychiatric disorder which usually afflicts people with dependents. Psychiatric disorders figure prominently in the differential diagnosis, and may complicate the clinical picture, sometimes even antedating the onset of neurological signs. Diagnosis is still usually clinical, for which some knowledge of the disease is required. Positron emission tomography, where available, can assist in early detection. Recent scientific breakthroughs have considerably improved the accuracy of predictive genetics, and the psychological outcome of such testing may be better than previously, but considerable ethical dilemmas have yet to be fully addressed. Genetic treatment is being considered. Drug treatments offer crude symptomatic improvement. Counselling and support services are essential, as are voluntary self-help organisations. Specific day and inpatient facilities are sparse.