22,038 research outputs found

    A Max-Plus Model of Asynchronous Cellular Automata

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    This paper presents a new framework for asynchrony. This has its origins in our attempts to better harness the internal decision making process of cellular automata (CA). Thus, we show that a max-plus algebraic model of asynchrony arises naturally from the CA requirement that a cell receives the state of each neighbour before updating. The significant result is the existence of a bijective mapping between the asynchronous system and the synchronous system classically used to update cellular automata. Consequently, although the CA outputs look qualitatively different, when surveyed on "contours" of real time, the asynchronous CA replicates the synchronous CA. Moreover, this type of asynchrony is simple - it is characterised by the underlying network structure of the cells, and long-term behaviour is deterministic and periodic due to the linearity of max-plus algebra. The findings lead us to proffer max-plus algebra as: (i) a more accurate and efficient underlying timing mechanism for models of patterns seen in nature, and (ii) a foundation for promising extensions and applications.Comment: in Complex Systems (Complex Systems Publications Inc), Volume 23, Issue 4, 201

    Why do British Indian children have an apparent mental health advantage?

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    BACKGROUND: Previous studies document a mental health advantage in British Indian children, particularly for externalising problems. The causes of this advantage are unknown. METHODS: Subjects were 13,836 White children and 361 Indian children aged 5-16 years from the English subsample of the British Child and Adolescent Mental Health Surveys. The primary mental health outcome was the parent Strengths and Difficulties Questionnaire (SDQ). Mental health was also assessed using the teacher and child SDQs; diagnostic interviews with parents, teachers and children; and multi-informant clinician-rated diagnoses. Multiple child, family, school and area factors were examined as possible mediators or confounders in explaining observed ethnic differences. RESULTS: Indian children had a large advantage for externalising problems and disorders, and little or no difference for internalising problems and disorders. This was observed across all mental health outcomes, including teacher-reported and diagnostic interview measures. Detailed psychometric analyses provided no suggestion of information bias. The Indian advantage for externalising problems was partly mediated by Indian children being more likely to live in two-parent families and less likely to have academic difficulties. Yet after adjusting for these and all other covariates, the unexplained Indian advantage only reduced by about a quarter (from 1.08 to .71 parent SDQ points) and remained highly significant (p < .001). This Indian advantage was largely confined to families of low socio-economic position. CONCLUSION: The Indian mental health advantage is real and is specific to externalising problems. Family type and academic abilities mediate part of the advantage, but most is not explained by major risk factors. Likewise unexplained is the absence in Indian children of a socio-economic gradient in mental health. Further investigation of the Indian advantage may yield insights into novel ways to promote child mental health and child mental health equity in all ethnic groups

    Developing the mental health workforce capacity in primary care: implementing the role of graduate primary care mental health workers in England

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    The scale of current demand on primary care services from people seeking help with common mental health problems places enormous pressure on the existing front line workers in general practice. The paucity of training opportunities and competing pressures to deliver improved services across a range of general practice targets remains a major challenge for primary care professionals. The impact of government policy, to improve both access to and choice of treatments, has raised public expectations. The commissioning of the graduate workforce, the graduate worker in primary care mental health(GWPCMH), commenced in 2002, in response to the publication of target numbers detailed in the Priorities and Planning Framework, (DoH, 2002). It signalled a determination to expand the workforce provision and improve the quality of care for service users with common mental health problems. This paper examines the scale of common mental health problems, the policy response and the commissioning process. Particular attention is given to examining the barriers that have been shown to affect implementation, identifying the key influencers and the resources required to train these workers

    Clinical outcomes of remote ischemic preconditioning prior to cardiac surgery: A meta‐analysis of randomized controlled trials

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    Background Multiple randomized controlled trials of remote ischemic preconditioning ( RIPC ) prior to cardiac surgery have failed to demonstrate clinical benefit. The aim of this updated meta‐analysis was to evaluate the effect of RIPC on outcomes following cardiac surgery. Methods and Results Searches of PubMed, Cochrane, EMBASE , and Web of Science databases were performed for 1970 to December 13, 2015. Randomized controlled trials comparing RIPC with a sham procedure prior to cardiac surgery performed with cardiopulmonary bypass were assessed. All‐cause mortality, acute kidney injury ( AKI ), and myocardial infarction were the primary outcomes of interest. We identified 21 trials that randomized 5262 patients to RIPC or a sham procedure prior to undergoing cardiac surgery. The majority of patients were men (72.6%) and the mean or median age ranged from 42.3 to 76.3 years. Of the 9 trials that evaluated mortality, 188 deaths occurred out of a total of 4210 randomized patients, with 96 deaths occurring in 2098 patients (4.6%) randomized to RIPC and 92 deaths occurring in 2112 patients (4.4%) randomized to a sham control procedure, demonstrating no significant reduction in all‐cause mortality (risk ratio [RR], 0.987; 95% CI , 0.653–1.492, P =0.95). Twelve studies evaluated AKI in 4209 randomized patients. In these studies, AKI was observed in 516 of 2091 patients (24.7%) undergoing RIPC and in 577 of 2118 patients (27.2%) randomized to a sham procedure. RIPC did not result in a significant reduction in AKI ( RR , 0.839; 95% CI , 0.703–1.001 [ P =0.052]). In 6 studies consisting of 3799 randomized participants, myocardial infarction occurred in 237 of 1891 patients (12.5%) randomized to RIPC and in 282 of 1908 patients (14.8%) randomized to a sham procedure, resulting in no significant reduction in postoperative myocardial infarction ( RR , 0.809; 95% CI , 0.615–1.064 [ P =0.13]). A subgroup analysis was performed a priori based on previous studies suggesting that propofol may mitigate the protective benefits of RIPC . Three studies randomized patients undergoing cardiac surgery to RIPC or sham procedure in the absence of propofol anesthesia. Most of these patients were men (60.3%) and the mean or median age ranged from 57.0 to 70.6 years. In this propofol‐free subgroup of 434 randomized patients, 71 of 217 patients (32.7%) who underwent RIPC developed AKI compared with 103 of 217 patients (47.5%) treated with a sham procedure. In this cohort, RIPC resulted in a significant reduction in AKI ( RR , 0.700; 95% CI , 0.527–0.930 [ P =0.014]). In studies of patients who received propofol anesthesia, 445 of 1874 (23.7%) patients randomized to RIPC developed AKI compared with 474 of 1901 (24.9%) who underwent a sham procedure. The RR for AKI was 0.928 (95% CI , 0.781–1.102; P =0.39) for RIPC versus sham. There was no significant interaction between the two subgroups ( P =0.098). Conclusions RIPC does not reduce morbidity or mortality in patients undergoing cardiac surgery with cardiopulmonary bypass. In the subgroup of studies in which propofol was not used, a reduction in AKI was seen, suggesting that propofol may interact with the protective effects of RIPC . Future studies should evaluate RIPC in the absence of propofol anesthesia. </jats:sec

    Assessment of total retinal blood flow using Doppler Fourier Domain Optical Coherence Tomography during systemic hypercapnia and hypocapnia.

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    The purpose of this study was to investigate changes in total retinal blood flow (RBF) using Doppler Fourier Domain Optical Coherence Tomography (Doppler FD-OCT) in response to the manipulation of systemic partial pressure of CO2 (PETCO2). Double circular Doppler blood flow scans were captured in nine healthy individuals (mean age ± standard deviation: 27.1 ± 4.1, six males) using the RTVue(™) FD-OCT (Optovue). PETCO2 was manipulated using a custom-designed computer-controlled gas blender (RespirAct(™)) connected to a sequential gas delivery rebreathing circuit. Doppler FD-OCT measurements were captured at baseline, during stages of hypercapnia (+5/+10/+15 mmHg PETCO2), return to baseline and during stages of hypocapnia (-5/-10/-15 mmHg PETCO2). Repeated measures analysis of variance (reANOVA) and Tukeys post hoc analysis were used to compare Doppler FD-OCT measurements between the various PETCO2 levels relative to baseline. The effect of PETCO2 on TRBF was also investigated using linear regression models. The average RBF significantly increased by 15% (P &lt; 0.0001) with an increase in PETCO2 and decreased significantly by 10% with a decrease in PETCO2 (P = 0.001). Venous velocity significantly increased by 3.11% from baseline to extreme hypercapnia (P &lt; 0.001) and reduced significantly by 2.01% at extreme hypocapnia (P = 0.012). No significant changes were found in the average venous area measurements under hypercapnia (P = 0.36) or hypocapnia (P = 0.40). Overall, increased and decreased PETCO2 values had a significant effect on RBF outcomes (P &lt; 0.002). In healthy individuals, altered end-tidal CO2 levels significantly changed RBF as measured by Doppler FD-OCT

    A call for the aggressive treatment of oligometastatic and oligo-recurrent non-small cell lung cancer.

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    Metastatic non-small cell lung cancer (NSCLC) carries a dismal prognosis. Clinical evidence suggests the existence of an intermediate, or oligometastatic, state when metastases are limited in number and/or location. In addition, following initial curative therapy, many patients present with limited metastatic disease, or oligo-recurrence. Metastasis-directed, anti-cancer therapies may benefit these patients. A growing evidence-base supports the use of hypofractionated, image-guided radiotherapy (HIGRT) for a variety of malignant conditions including inoperable stage I NSCLC and many metastatic sites. When surgical resection is not possible, HIGRT offers an effective alternative for local treatment of limited metastatic disease. Early studies have produced promising results when HIGRT was delivered to all known sites of disease in patients with oligometastatic/oligo-recurrent NSCLC. In a population of patients formerly considered rapidly terminal, these studies report five year overall survival rates of 13-22%. HIGRT for metastatic NSCLC warrants further study. We call for large, intergroup, and even international randomized trials incorporating HIGRT and other metastasis-directed therapies into the treatment of patients with oligometastatic/oligo-recurrent NSCLC

    Influences of zero hour contracts and disability – Analysis of the 1970 British Cohort study

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    RATIONALE: In recent decades, there has been a rise of the “gig-economy” where workers are given non-standard work agreements, and work is completed in an ad-hoc nature. It was believed people this would create greater access to employment for people with disability as there would no longer be a need to disclose disability and could ‘pick and choose’ work. Although, little research has been done on the health-outcomes of working in non-standard agreements compared to traditional employment, and in particular it's impact on disability. OBJECTIVE: This study examines one particular non-standard workplace agreement, working under zero hour contracts as the main source of income as a predictor for disability at age 46 and how income levels effect this, while controlling for pre-existing illness at age 34. METHOD: This study used existing data made available in the 1970 British Cohort study. Age 46 and Age 34 sweeps were used, including predictors for disability such as zero hour work, sex, and income, and binary multiple logistic regression was used. RESULTS: This study was able to demonstrate that there is an association between working under a zero hour contract as the main source of income and disability. Further, this study shows that this association is statistically significant at low incomes but not at high incomes. CONCLUSIONS: The relationship between zero hour work and disability presented in this study may suggest that zero hour work will produce a burden on healthcare systems and limit further economic outputs by limiting individual's capacity for work
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