Phase transitions in the classical simulability of open quantum systems.

We introduce a Langevin unravelling of the density matrix evolution of an open quantum system over matrix product states, which we term the time-dependent variational principle-Langevin equation. This allows the study of entanglement dynamics as a function of both temperature and coupling to the environment. As the strength of coupling to and temperature of the environment is increased, we find a transition where the entanglement of the individual trajectories saturates, permitting a classical simulation of the system for all times. This is the Hamiltonian open system counterpart of the saturation in entanglement found in random circuits with projective or weak measurements. If a system is open, there is a limit to the advantage in simulating its behaviour on a quantum computer, even when that evolution harbours important quantum effects. Moreover, if a quantum simulator is in this phase, it cannot simulate with quantum advantage.

Patient Preparation and Radiation Protection Guidance for Adult Patients Undergoing Radioiodine Treatment for Thyroid Cancer in the UK.

Radioactive iodine is a highly effective treatment for thyroid cancer and has now been used in clinical practice for more than 80 years. In general, the treatment is well tolerated. However, it can be logistically quite complex for patients due to the need to reduce iodine intake and achieve high levels of thyroid-stimulating hormone prior to treatment. Radiation protection precautions must also be taken to protect others from unnecessary radiation exposure following treatment. It has been well documented by thyroid cancer patient support groups that there is significant variation in practice across the UK. It is clear that some patients are being asked to observe unnecessarily burdensome restrictions that make it more difficult for them to tolerate the treatment. At the instigation of these support groups, a multidisciplinary group was assembled to examine the evidence and generate guidance on best practice for the preparation of patients for this treatment and the management of subsequent radiation protection precautions, with a focus on personalising the advice given to individual patients. The guidance includes advice about managing particularly challenging situations, for example treating patients who require haemodialysis. We have also worked together to produce a patient information leaflet covering these issues. We hope that the guidance document and patient information leaflet will assist centres in improving our patients' experience of receiving radioactive iodine. The patient information sheet is available as Supplementary Material to this article.

End-cretaceous mass extinction event: argument for terrestrial causation.

The end-Cretaceous mass extinctions were not a geologically instantaneous event and were selective in character. These features are incompatible with the original Alvarez hypothesis of their being caused by a single asteroid impact that produced a world-embracing dust cloud with devastating environmental consequences. By analysis of physical and chemical evidence from the stratigraphic record it is shown that a modified extraterrestrial model in which stepwise extinctions resulted from encounter with a comet shower is less plausible than one intrinsic to the earth, involving significant disturbance in the mantle.

The Lyapunov spectra of quantum thermalisation.

Thermalisation in closed quantum systems occurs through a process of dephasing due to parts of the system outside of the window of observation, gradually revealing the underlying thermal nature of eigenstates. In contrast, closed classical systems thermalize due to dynamical chaos. We demonstrate a deep link between these processes. Projecting quantum dynamics onto variational states using the time-dependent variational principle, results in classical chaotic Hamiltonian dynamics. We study an infinite spin chain in two ways-using the matrix product state ansatz for the wavefunction and for the thermofield purification of the density matrix-and extract the full Lyapunov spectrum of the resulting dynamics. We show that the entanglement growth rate is related to the Kolmogorov-Sinai entropy of dynamics projected onto states with appropriate entanglement, extending previous results about initial entanglement growth to all times. The Lyapunov spectra for thermofield descriptions of thermalizing systems show a remarkable semi-circular distribution.

Electrostimulation for promoting recovery of movement or functional ability after stroke.

BACKGROUND: Electrostimulation might improve motor recovery after stroke by providing neuromuscular re-training. OBJECTIVES: To find if electrostimulation improved functional motor ability, and the ability to undertake activities of daily living. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched August 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2004), MEDLINE (1966 to January 2004), EMBASE (1980 to January 2004), CINAHL (1982 to January 2004), AMED - Allied and Complementary Medicine Database (1985 to January 2004), Physiotherapy Evidence Database (PEDro), REHABDATA and the ISI Science Citation Index (1981 to 2003). We placed a request on the PHYSIO e-mail discussion list and contacted authors of relevant studies to elicit any unpublished or ongoing studies, searched the reference lists of included trials and contacted trialists. SELECTION CRITERIA: Randomised controlled trials of electrostimulation delivered to the peripheral neuromuscular system which was designed to improve voluntary movement control, functional motor ability and activities of daily living. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Of the 2077 references identified, 24 trials were included in this review. For electrostimulation compared with no treatment this review found that electrostimulation improved some aspects of functional motor ability and some aspects of motor impairment and normality of movement. In addition, there was a significant difference in favour of no treatment compared with electrostimulation for an aspect of functional motor ability. For electrostimulation compared with placebo this review found that electrostimulation improved an aspect of functional motor ability. For electrostimulation compared with conventional physical therapy this review found that electrostimulation improved an aspect of motor impairment. There were no statistically significant differences between electrostimulation and control treatment for all other outcomes. However, these results need to be interpreted with reference to the following: (1) the majority of analyses only contained one trial; (2) variation was found between included trials in time after stroke, level of functional deficit, and dose of electrostimulation; and (3) the possibility of selection and detection bias in the majority of included trials. AUTHORS' CONCLUSIONS: At present, there are insufficient robust data to inform clinical use of electrostimulation for neuromuscular re-training. Research is needed to address specific questions about the type of electrostimulation that might be most effective, in what dose and at what time after stroke.

Quality and costs of community-based residential supports, village communities, and residential campuses in the United Kingdom.

The costs, nature, and benefits of residential supports were examined for 86 adults with mental retardation living in village communities, 133 adults living in newly built residential campuses, and 281 adults living in dispersed housing schemes (small community-based group homes and supported living). Results indicated that (a) the adjusted comprehensive costs of provision in dispersed housing schemes were 15% higher than in residential campuses and 20% higher than in village communities; (b) dispersed housing schemes and village communities offered a significantly greater quality of care than did residential campuses; and (c) there appeared to be distinct patterns of quality of life benefits associated with dispersed housing schemes and village communities, with both approaches offering a greater quality of life than did residential campuses.

Quality and costs of supported living residences and group homes in the United Kingdom.

Information was collected on 63 adults in supported living residences, 55 adults in small group homes, and 152 adults in large group homes. Results indicated that (a) there were no statistically significant differences in service costs once these had been adjusted to take account of participant characteristics; (b) compared with participants living in small group homes, those in supported living residences had greater choice, participated in more community-based activities, experienced fewer scheduled activities, were more likely to have had their home vandalized, and were considered at greater risk of exploitation; (c) compared with participants living in large group homes, those in small group homes had larger social networks, more people in their social networks who were not staff, not family, and did not have mental retardation. These residents were considered at less risk of abuse.

The cost effectiveness of specialised facilities for service users with persistent challenging behaviours.

Little systematic research relates specifically to the last people to leave a psychiatric hospital at the end of a closure programme. The long-running evaluation of the reprovision of services from Friern Hospital in North London allowed a special study to be made of such a group (67 people in all), whose range of problem behaviours made placement in community settings most difficult. The patients were relatively young, with a shorter length of stay than the remainder of the former long-stay hospital population. They were assessed three times: before leaving Friern, and one and 5 years after relocation. The social and clinical characteristics of each person were measured, and the full costs of their care calculated. The "difficult-to-place" patients moved to four highly staffed rehabilitation facilities, where the total cost of their care was, on average, 1230 UK pounds per week. There was no overall change in their psychiatric state over the 5 years after they left Friern Hospital although, in the longer-term, they gained skills in several areas of daily functioning. Most importantly, there was a fall of almost 50% in the number of challenging behaviours exhibited by the study group. At the five-year follow-up point, the cost of care had fallen, on average, by 170 UK pounds per week, and 24 people had been able to move to more independent accommodation arrangements. Study participants had gained a new network of community service contacts, and used services provided by a greater variety of agencies. The indicators suggest that high expenditure on alternative care was justified retrospectively by overall long-term outcomes. An important policy lesson from the Friern Hospital reprovision study is that adequate funds should be reserved until the end of the closure programme to allow the investment of resources in provision for patients with the most severe problem behaviours.

Environmental opportunities and supports for exercising self-determination in community-based residential settings.

Information was collected on the environmental opportunities for exercising self-determination among 281 adults with mental retardation receiving community-based residential supports. The results indicated that: (1) the majority of participants had little or no opportunity to exercise self-determination over major life decisions (e.g., with whom and where to live, the recruitment and retention of care staff); (2) even in more mundane areas, such as where and when to eat, the majority of participants were not supported to exercise effective control; (3) variation in environmental opportunities to exercise self-determination was strongly related to a range of factors including participant ability, previous residential history, and structural and procedural aspects of the residential supports currently provided.

Lifestyle related risk factors for poor health in residential settings for people with intellectual disabilities.

Little information is available on the prevalence and determinants of lifestyle related risk factors for poor health (obesity, poor diet, physical inactivity, smoking and alcohol abuse) among people with intellectual disabilities. This study reports the prevalence of these risk factors for 500 people with intellectual disabilities living in different forms of residential provision in the UK. Variables which predict the presence of these risk factors are also identified. While levels of smoking and alcohol abuse were low, the prevalence of poor diet, obesity in women and physical inactivity was high. Analyses of predictors of risk factors present a mixed pattern with regard to participant and service characteristics, with greater ability and less restrictive residential settings being associated with poor diet, smoking and obesity, but physical inactivity being associated with lower ability and more restrictive settings. It is argued that increasing levels of moderate or vigorous physical activity among people with intellectual disabilities would be the single most effective way of improving the health of people with intellectual disabilities.

Community mental health care for former hospital in-patients. Predicting costs from needs and diagnoses.

BACKGROUND: In the UK the replacement of long-term in-patient care with community-based support has been part of central government health policy for many years. One of the challenges of implementing such a policy is the prediction of support and service needs in the community and the associated costs. METHOD: Using research data from north London analyses were undertaken to examine the associations between service use and costs in the community and the characteristics of hospital in-patients. RESULTS: Although clinical diagnosis was not a useful predictor of either service utilisation or costs, more than a third of the variation in community care costs could be explained by symptoms, behaviour and personal characteristics at least one year earlier.

Viral hepatitis A to E. An update.

The authors' aim is to present a survey of the current understanding of viral hepatitis with emphasis on hepatitis B and C and the mechanisms of prevention. Abbreviations used in this article are shown in Table 1. An overview of viral hepatitis A to E is provided in Table 2.

Treatment and management of challenging behaviours in congregate and noncongregate community-based supported accommodation.

OBJECTIVES: To compare the nature and prevalence of use of procedures employed to treat and manage challenging behaviours across two approaches to providing community-based supported accommodation for people with intellectual disabilities (ID) and severe challenging behaviour: noncongregate settings where the minority of residents have challenging behaviour, and congregate settings where the majority of residents have challenging behaviour. SETTING: Community-based supported accommodation for people with ID and challenging behaviour. DESIGN: Longitudinal matched groups design. MAIN OUTCOME MEASURES: The nature and prevalence of use of procedures employed to treat and manage challenging behaviours. Observed and reported severity of challenging behaviours. RESULTS: Both types of settings were associated with low prevalence of use of behavioural technologies for the reduction of challenging behaviour (less than 15% of participants). In contrast, high proportions of participant received antipsychotic medication in both noncongregate (56%) and congregate (80%) settings. Congregate settings were associated with the increased use of physical restraint as a reactive management strategy, with over half of participants being in receipt of physical restraint by two or more members of staff. DISCUSSION: Changes in reported and observed challenging behaviour over a 10-month period were slight. The use of evidence-based behavioural technologies for the reduction of challenging behaviour may have led to better outcomes.

The costs of accommodation and care. Community provision for former long-stay psychiatric hospital patients.

The development of community services to replace two long-stay psychiatric hospitals in the North East Thames Health Authority region of the UK has been the subject of a research programme since 1985. The economic evaluation is conducted by the Personal Social Services Research Unit; research results relating to the first five cohorts of hospital leavers are reported in this paper. When followed up 1 year after discharge, almost half of the sample were living in highly supported residential care units, most of which were managed by district health authorities. More than 40 services provided outside the accommodation facility were used by clients and, although contact with certain professionals remained constant, some changes in service use over time were marked. The average total cost of community care for this group was 493 pounds per week (1992-93 prices), accommodation facility costs comprising approximately 85% of the total. In the new service configuration, district health authorities fund half of the costs of supporting the hospital leavers, 50% less than when they funded long-stay hospital placements. The rest of the funding burden is borne by a range of agencies, resulting in pressure on budgets and staff case loads.

Service support to people in Wales with severe intellectual disability and the most severe challenging behaviours: processes, outcomes and costs.

A survey of people with severe intellectual disability and the most severe challenging behaviour in Wales identified five adults living in family homes, 17 in new specialist community housing and 19 in traditional services. With the omission of two people from the latter group and with a restricted collection of data for people living in the family home, the present study explored service input, outcome and costs across the three setting types. Process and outcome indicators for the family home group, who received little service input, were better than those for the traditional service group, although less good than those for the community house group. The specialist community home model produced significant gains over the traditional services in virtually all areas. Across the residential data set as a whole, there was no association between staff:resident ratios and severity of disability or between costs and severity of disability. This was largely true of the service types separately. There was a relationship between costs and service quality. However, this association was underpinned by gross differences between community houses and traditional settings. Costs, processes and outcomes ceased to be related when the two residential types were considered separately. Although higher costs of new community services compared to traditional services may be set against improved outcomes, high costs within the former could not be related to benefit. Outcome indicators were generally related to each other, suggesting that high quality in one sense was matched by high quality in other senses. Outcome was significantly associated with the ability of residents. Outcome indicators also tended to be related to observed staff performance, which was independent of resident ability. Therefore, outcome may be considered as dually determined by differences in resident ability and in what staff did.

Receipt of psychotropic medication by people with intellectual disability in residential settings.

Previous studies have reported that the rate of prescription of antipsychotic medication for people with intellectual disability is far in excess of the expected prevalence of psychoses for this population. Recent research identifying factors which predict the use of psychotropic medication suggests that challenging behaviour may play a key role in determining the receipt of antipsychotic medication. The present study reports the prevalence of psychoactive medication receipt for 500 people with intellectual disability living in different forms of residential provision in the UK. Variables which predict the receipt of psychotropic medication are also identified. The results show differences between forms of residential provision in rates of medication receipt. Analyses of predictors of psychotropic medication receipt suggest that, whilst the receipt of antidepressants is predicted by symptoms of mental ill health, the receipt of both antipsychotics and hypnotics/anxiolytics is predicted by variables related to challenging behaviour.

Social networks of people with mental retardation in residential settings.

Information was collected on the social networks of 500 adults with mental retardation receiving different types of residential supports. Results indicated that (a) the reported median size of participants' social networks (excluding staff) was 2 people; (b) 83% of participants were reported to have a staff member; 72%, a member of their family; 54%, another person with mental retardation; and 30%, a person who did not fit into any of these categories in their social network; (c) variation in the size and composition of participants' social networks was associated with a range of variables, including the personal characteristics of residents (age, autism, ability, and challenging behavior), the type of previous and current accommodation, staffing ratios, institutional climate, and the implementation of "active support."