Synchronization of High-Dimensional Dynamical Systems

There are many examples of high-dimensional systems in nature. Often these systems behave in synchrony even though they possess a large number of degrees of freedom. Far fewer of these types of systems exist in the laboratory, and even fewer techniques exist with which to analyze them. As experimental capability increases, and more high-dimensional laboratory systems are fabricated, universal tools must be developed to observe and analyze the dynamics of these systems. This thesis will present experiments and analysis of two high-dimensional systems, coupled fiber ring lasers and a liquid crystal spatial light modulator with optoelectronic feedback. Two identically constructed mutually coupled erbium doped fiber ring lasers were studied and were found to synchronize at very low coupling strengths. Synchronization error was characterized as a function of coupling strength. Optical frequency-locking and hopping as a result of the mutual coupling was also observed. Methods for detecting the leader and follower laser as well as role switching, a form of spontaneous symmetry-breaking, were developed. These include a spatiotemporal representation of the intensities within each ring laser and the use of Karhunen-Loeve decomposition. A delay-differential equation model was developed and the numerical simulations were in agreement with the experiment. Chaotic communication was achieved in this system with bit rates of 125 MHz, limited by the detection speed. A liquid crystal spatial light modulator (SLM) was also studied. When used as a dynamic holographic grating, this device allowed the fabrication of a variety of reshaped laser beams, including multiple Gaussian beams, optical billiards, and propagating Bessel beams. When configured in an optoelectronic feedback loop, the SLM displays spatiotemporal chaos and using the auxiliary system method, we have achieved generalized synchronization of this system. The space-time patterns as well as the transients to synchronization have been characterized as a function of the bias voltage across the liquid crystal. The analysis techniques used in this thesis can be applied to other high-dimensional systems

Psychiatric referrals from the police : an examination of police officers' action and interaction with psychiatrists

There are two main foci in this research. The first has to do with police officers' management of psychiatric referrals, using their powers under Section 136 of the Mental Health Act, the second with interprofessional relations between the police and psychiatrists. A Section 136 case is defined so as to include all referrals where a mental health disposal is initiated by the police as opposed to a court or other mental health professional. The research is an attempt to describe police officers involvement with psychiatric referrals and the nature of and reasons behind the decisions they make, and to understand the nature of professional relationships that exist between police officers and psychiatrists in applying this part of the Mental Health Act. The concepts used, and theoretical underpinnings of the research are in the main derived from the sociology of 'mental illness'. Use, has been made of the theory of professional dominance to analyse police action and interaction with psychiatrists. Both quantitative and qualitative methods of data collection and analysis have been used. Primacy has not been given to one or other approach, rather an attempt has been made to integrate both, so as to present as full a picture as possible of the issues under investigation. Data was primarily collected by means of interviews with police officers from 11 different police stations in the North East Metropolitan Police area. This was supplemented by the use of participant observation at one police station, interviews with psychiatrists at two hospitals and analysis of police documents and administrative records. The study has been divided into three sections: preparing for and carrying out the research (Chapters 1-4); the analysis and presentation of findings (Chapters 5-8); discussion and implications of the results and re-examining the theory (Chapter 9-10). It was rare for officers to initiate referrals themselves, it was mainly as a response to others that they became involved. Officers were generally unaware that they were responding to a mental health emergency prior to arriving at an incident, and decisions to apprehend were made for policing rather than psychiatric reasons. Officers did not always use Section 136 as an authority for arrest where a psychiatric disposal was subsequently sought. A combination of physical restraint and verbal strategies were used to manage referrals. Officers tended not to treat these differently to other suspects, whilst on the streets, but treated them less punitively than other detainees once at the station. It was found that there was a tendency to exclude other forms of deviancy in identifying mental disorder. Most referrals could have been charged with a criminal offence and officers' reasons for not preferring charges were examined, of which external considerations, (such as the policy of the courts) were found to be important. Police and psychiatrists generally shared the same perceptions about their client group in terms of the latter's appropriateness to be dealt with by the psychiatric services. With the exception of police ability to diagnose mental disorder, there was agreement about the nature of officer's role in relation to Section 136. Interprofessional contact and perceptions of one another were characterised by distance and indifference. At the hospital, psychiatrists assumed a superordinate role over the police officers. However, police officers exercised considerable autonomy over decision making at the police station which acted to threaten the psychiatrists gatekeeping powers

Psychiatric referrals from the police : an examination of police officers' action and interaction with psychiatrists

There are two main foci in this research. The first has to do with police officers' management of psychiatric referrals, using their powers under Section 136 of the Mental Health Act, the second with interprofessional relations between the police and psychiatrists. A Section 136 case is defined so as to include all referrals where a mental health disposal is initiated by the police as opposed to a court or other mental health professional. The research is an attempt to describe police officers involvement with psychiatric referrals and the nature of and reasons behind the decisions they make, and to understand the nature of professional relationships that exist between police officers and psychiatrists in applying this part of the Mental Health Act. The concepts used, and theoretical underpinnings of the research are in the main derived from the sociology of 'mental illness'. Use, has been made of the theory of professional dominance to analyse police action and interaction with psychiatrists. Both quantitative and qualitative methods of data collection and analysis have been used. Primacy has not been given to one or other approach, rather an attempt has been made to integrate both, so as to present as full a picture as possible of the issues under investigation. Data was primarily collected by means of interviews with police officers from 11 different police stations in the North East Metropolitan Police area. This was supplemented by the use of participant observation at one police station, interviews with psychiatrists at two hospitals and analysis of police documents and administrative records. The study has been divided into three sections: preparing for and carrying out the research (Chapters 1-4); the analysis and presentation of findings (Chapters 5-8); discussion and implications of the results and re-examining the theory (Chapter 9-10). It was rare for officers to initiate referrals themselves, it was mainly as a response to others that they became involved. Officers were generally unaware that they were responding to a mental health emergency prior to arriving at an incident, and decisions to apprehend were made for policing rather than psychiatric reasons. Officers did not always use Section 136 as an authority for arrest where a psychiatric disposal was subsequently sought. A combination of physical restraint and verbal strategies were used to manage referrals. Officers tended not to treat these differently to other suspects, whilst on the streets, but treated them less punitively than other detainees once at the station. It was found that there was a tendency to exclude other forms of deviancy in identifying mental disorder. Most referrals could have been charged with a criminal offence and officers' reasons for not preferring charges were examined, of which external considerations, (such as the policy of the courts) were found to be important. Police and psychiatrists generally shared the same perceptions about their client group in terms of the latter's appropriateness to be dealt with by the psychiatric services. With the exception of police ability to diagnose mental disorder, there was agreement about the nature of officer's role in relation to Section 136. Interprofessional contact and perceptions of one another were characterised by distance and indifference. At the hospital, psychiatrists assumed a superordinate role over the police officers. However, police officers exercised considerable autonomy over decision making at the police station which acted to threaten the psychiatrists gatekeeping powers

Achieving change in primary care—causes of the evidence to practice gap : systematic reviews of reviews

Acknowledgements The Evidence to Practice Project (SPCR FR4 project number: 122) is funded by the National Institute of Health Research (NIHR) School for Primary Care Research (SPCR). KD is part-funded by the National Institute for Health Research (NIHR) Collaborations for Leadership in Applied Research and Care West Midlands and by a Knowledge Mobilisation Research Fellowship (KMRF-2014-03-002) from the NIHR. This paper presents independent research funded by the National Institute of Health Research (NIHR). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. Funding This study is funded by the National Institute for Health Research (NIHR) School for Primary Care Research (SPCR).Peer reviewedPublisher PD

The Relationship between Childhood Obesity, Low Socioeconomic Status, and Race/Ethnicity: Lessons from Massachusetts

Background: Previous studies have shown race/ethnicity, particularly African American and/or Hispanic status, to be a predictor of overweight/obese status in children. However, these studies have failed to adjust for low socioeconomic status (SES). This study assessed whether race/ethnicity remained an independent predictor of childhood obesity when accounting for variations in SES (low-income) among communities in Massachusetts. Methods: This study was based on 2009 summarized data from 68 Massachusetts school districts with 111,799 students in grades 1, 4, 7, and 10. We studied the relationship between the rate of overweight/obese students (mean?=?0.32; range?=?0.10?0.46), the rate of African American and Hispanic students (mean?=?0.17; range?=?0.00?0.90), and the rate of low-income students (mean?=?0.27; range?=?0.02?0.87) in two and three dimensions. The main effect of the race/ethnicity rate, the low-income rate, and their interaction on the overweight and obese rate was investigated by multiple regression modeling. Results: Low-income was highly associated with overweight/obese status (p?Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140341/1/chi.2015.0029.pd

Changing Preferences for Survival After Hospitalization With Advanced Heart Failure

ObjectivesThis study was designed to analyze how patient preferences for survival versus quality-of-life change after hospitalization with advanced heart failure (HF).BackgroundAlthough patient-centered care is a priority, little is known about preferences to trade length of life for quality among hospitalized patients with advanced HF, and it is not known how those preferences change after hospitalization.MethodsThe time trade-off utility, symptom scores, and 6-min walk distance were measured in 287 patients in the ESCAPE (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheter Effectiveness) trial at hospitalization and again during 6 months after therapy to relieve congestion.ResultsWillingness to trade was bimodal. At baseline, the median trade for better quality was 3 months' survival time, with a modest relation to symptom severity. Preference for survival time was stable for most patients, but increase after discharge occurred in 98 of 145 (68%) patients initially willing to trade survival time, and was more common with symptom improvement and after therapy guided by pulmonary artery catheters (p = 0.034). Adjusting days alive after hospital discharge for patients' survival preference reduced overall days by 24%, with the largest reduction among patients dying early after discharge (p = 0.0015).ConclusionsPreferences remain in favor of survival for many patients despite advanced HF symptoms, but increase further after hospitalization. The bimodal distribution and the stability of patient preference limit utility as a trial end point, but support its relevance in design of care for an individual patient

Telehealth for patients at high risk of cardiovascular disease: pragmatic randomised controlled trial

Objective: To assess whether non-clinical staff can effectively manage people at high risk of cardiovascular disease using digital health technologies. Design: Pragmatic, multicentre, randomised controlled trial. Setting: 42 general practices in three areas of England. Participants: Between 3 December 2012 and 23 July 2013 we recruited 641 adults aged 40 to 74 years with a 10 year cardiovascular disease risk of 20% or more, no previous cardiovascular event, at least one modifiable risk factor (systolic blood pressure ≥140 mm Hg, body mass index ≥30, current smoker), and access to a telephone, the internet, and email. Participants were individually allocated to intervention (n=325) or control (n=316) groups using automated randomisation stratified by site, minimised by practice and baseline risk score. Interventions: Intervention was the Healthlines service (alongside usual care), comprising regular telephone calls from trained lay health advisors following scripts generated by interactive software. Advisors facilitated self-management by supporting participants to use online resources to reduce risk factors, and sought to optimise drug use, improve treatment adherence, and encourage healthier lifestyles. The control group comprised usual care alone. Main outcome measures: The primary outcome was the proportion of participants responding to treatment, defined as maintaining or reducing their cardiovascular risk after 12 months. Outcomes were collected six and 12 months after randomisation and analysed masked. Participants were not masked. Results: 50% (148/295) of participants in the intervention group responded to treatment compared with 43% (124/291) in the control group (adjusted odds ratio 1.3, 95% confidence interval 1.0 to 1.9; number needed to treat=13); a difference possibly due to chance (P=0.08). The intervention was associated with reductions in blood pressure (difference in mean systolic −2.7 mm Hg (95% confidence interval −4.7 to −0.6 mm Hg), mean diastolic −2.8 (−4.0 to −1.6 mm Hg); weight −1.0 kg (−1.8 to −0.3 kg), and body mass index −0.4 (−0.6 to −0.1) but not cholesterol −0.1 (−0.2 to 0.0), smoking status (adjusted odds ratio 0.4, 0.2 to 1.0), or overall cardiovascular risk as a continuous measure (−0.4, −1.2 to 0.3)). The intervention was associated with improvements in diet, physical activity, drug adherence, and satisfaction with access to care, treatment received, and care coordination. One serious related adverse event occurred, when a participant was admitted to hospital with low blood pressure. Conclusions: This evidence based telehealth approach was associated with small clinical benefits for a minority of people with high cardiovascular risk, and there was no overall improvement in average risk. The Healthlines service was, however, associated with improvements in some risk behaviours, and in perceptions of support and access to care

Barriers and facilitators to reducing frequent laboratory testing for patients who are stable on warfarin: a mixed methods study of de-implementation in five anticoagulation clinics

Abstract Background Patients on chronic warfarin therapy require regular laboratory monitoring to safely manage warfarin. Recent studies have challenged the need for routine monthly blood draws in the most stable warfarin-treated patients, suggesting the safety of less frequent laboratory testing (up to every 12 weeks). De-implementation efforts aim to reduce the use of low-value clinical practices. To explore barriers and facilitators of a de-implementation effort to reduce the use of frequent laboratory tests for patients with stable warfarin management in nurse/pharmacist-run anticoagulation clinics, we performed a mixed-methods study conducted within a state-wide collaborative quality improvement collaborative. Methods Using a mixed-methods approach, we conducted post-implementation semi-structured interviews with a total of eight anticoagulation nurse or pharmacist staff members at five participating clinic sites to assess barriers and facilitators to de-implementing frequent international normalized ratio (INR) laboratory testing among patients with stable warfarin control. Interview guides were based on the Tailored Implementation for Chronic Disease (TICD) framework. Informed by interview themes, a survey was developed and administered to all anticoagulation clinical staff (n = 62) about their self-reported utilization of less frequent INR testing and specific barriers to de-implementing the standard (more frequent) INR testing practice. Results From the interviews, four themes emerged congruent with TICD domains: (1) staff overestimating their actual use of less frequent INR testing (individual health professional factors), (2) barriers to appropriate patient engagement (incentives and resources), (3) broad support for an electronic medical record flag to identify potentially eligible patients (incentives and resources), and (4) the importance of personalized nurse/pharmacist feedback (individual health professional factors). In the survey (65% response rate), staff report offering less frequent INR testing to 56% (46–66%) of eligible patients. Most survey responders (n = 24; 60%) agreed that an eligibility flag in the electronic medical record would be very helpful. Twenty-four (60%) respondents agreed that periodic, personalized feedback on use of less frequent INR testing would also be helpful. Conclusions Leveraging information system notifications, reducing additional work load burden for participating patients and providers, and providing personalized feedback are strategies that may improve adoption and utilization new policies in anticoagulation clinics that focus on de-implementation.https://deepblue.lib.umich.edu/bitstream/2027.42/137702/1/13012_2017_Article_620.pd

Self-management support interventions to reduce health care utilisation without compromising outcomes: a systematic review and meta-analysis

Background: There is increasing interest in the role of �self-management� interventions to support the management of long-term conditions in health service settings. Self-management may include patient education, support for decision-making, self-monitoring and psychological and social support. Self-management support has potential to improve the efficiency of health services by reducing other forms of utilisation (such as primary care or hospital use), but a shift to self-management may lead to negative outcomes, such as patients who feel more anxious about their health, are less able to cope, or who receive worse quality of care, all of which may impact on their health and quality of life. We sought to determine which models of self-management support are associated with significant reductions in health services utilisation without compromising outcomes among patients with long-term conditions. Methods: We used systematic review with meta-analysis. We included randomised controlled trials in patients with long-term conditions which included self-management support interventions and reported measures of service utilisation or costs, as well as measures of health outcomes (standardized disease specific quality of life, generic quality of life, or depression/anxiety).We searched multiple databases (CENTRAL, CINAHL, Econlit, EMBASE, HEED, MEDLINE, NHS EED and PsycINFO) and the reference lists of published reviews. We calculated effects sizes for both outcomes and costs, and presented the results in permutation plots, as well as conventional meta-analyses. Results: We included 184 studies. Self-management support was associated with small but significant improvements in health outcomes, with the best evidence of effectiveness in patients with diabetic, respiratory, cardiovascular and mental health conditions. Only a minority of self-management support interventions reported reductions in health care utilisation in association with decrements in health. Evidence for reductions in utilisation associated with self-management support was strongest in respiratory and cardiovascular problems. Studies at higher risk of bias were more likely to report benefits. Conclusions: Self-management support interventions can reduce health service utilization without compromising patient health outcomes, although effects were generally small, and the evidence was strongest in respiratory and cardiovascular disorders. Further work is needed to determine which components of self-management support are most effective