Crystallization of calcite from amorphous calcium carbonate: earthworms show the way

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Estimating intracluster correlation for ordinal data

Purpose: In this paper we consider the estimation of intracluster correlation for ordinal data. We focus on pure-tone audiometry hearing threshold data, where thresholds are measured in 5 decibel increments. We estimate the intracluster correlation for tests from iPhone-based hearing assessment application as a measure of test/retest reliability. Methods: We present a method to estimate the intracluster correlation using mixed effects cumulative logistic and probit models, which assume the outcome data are ordinal. This contrasts with using a mixed effects linear model which assumes that the outcome data are continuous. Results: In simulation studies we show that using a mixed effects linear model to estimate the intracluster correlation for ordinal data results in a negative finite sample bias, while using mixed effects cumulative logistic or probit models reduces this bias. The estimated intracluster correlation for the iPhone-based hearing assessment application is higher when using the mixed effects cumulative logistic and probit models compared to using a mixed effects linear model. Conclusion: When data are ordinal, using mixed effects cumulative logistic or probit models reduces the bias of intracluster correlation estimates relative to using a mixed effects linear model.Comment: 11 pages, 3 table

Placental genomic risk scores and early neurodevelopmental outcomes

Tracing the early paths leading to developmental disorders is critical for prevention. In previous work, we detected an interaction between genomic risk scores for schizophrenia (GRSs) and early-life complications (ELCs), so that the liability of the disorder explained by genomic risk was higher in the presence of a history of ELCs, compared with its absence. This interaction was specifically driven by loci harboring genes highly expressed in placentae from normal and complicated pregnancies [G. Ursini et al., Nat. Med. 24, 792–801 (2018)]. Here, we analyze whether fractionated genomic risk scores for schizophrenia and other developmental disorders and traits, based on placental gene-expression loci (PlacGRSs), are linked with early neurodevelopmental outcomes in individuals with a history of ELCs. We found that schizophrenia’s PlacGRSs are negatively associated with neonatal brain volume in singletons and offspring of multiple pregnancies and, in singletons, with cognitive development at 1 y and, less strongly, at 2 y, when cognitive scores become more sensitive to other factors. These negative associations are stronger in males, found only with GRSs fractionated by placental gene expression, and not found in PlacGRSs for other developmental disorders and traits. The relationship of PlacGRSs with brain volume persists as an anlage of placenta biology in adults with schizophrenia, again selectively in males. Higher placental genomic risk for schizophrenia, in the presence of ELCs and particularly in males, alters early brain growth and function, defining a potentially reversible neurodevelopmen

Psychosocial factors and their predictive value in chiropractic patients with low back pain: a prospective inception cohort study

BACKGROUND: Being able to estimate the likelihood of poor recovery from episodes of back pain is important for care. Studies of psychosocial factors in inception cohorts in general practice and occupational populations have begun to make inroads to these problems. However, no studies have yet investigated this in chiropractic patients. METHODS: A prospective inception cohort study of patients presenting to a UK chiropractic practice for new episodes of non-specific low back pain (LBP) was conducted. Baseline questionnaires asked about age, gender, occupation, work status, duration of current episode, chronicity, aggravating features and bothersomeness using Deyo's 'Core Set'. Psychological factors (fear-avoidance beliefs, inevitability, anxiety/distress and coping, and co-morbidity were also assessed at baseline. Satisfaction with care, number of attendances and pain impact were determined at 6 weeks. Predictors of poor outcome were sought by the calculation of relative risk ratios. RESULTS: Most patients presented within 4 weeks of onset. Of 158 eligible and willing patients, 130 completed both baseline and 6-week follow-up questionnaires. Greatest improvements at 6 weeks were in interference with normal work (ES 1.12) and LBP bothersomeness (ES 1.37). Although most patients began with moderate-high back pain bothersomeness scores, few had high psychometric ones. Co-morbidity was a risk for high-moderate interference with normal work at 6 weeks (RR 2.37; 95% C.I. 1.15–4.74). An episode duration of >4 weeks was associated with moderate to high bothersomeness at 6 weeks (RR 2.07; 95% C.I. 1.19 – 3.38) and negative outlook (inevitability) with moderate to high interference with normal work (RR 2.56; 95% C.I. 1.08 – 5.08). CONCLUSION: Patients attending a private UK chiropractic clinic for new episodes of non-specific LBP exhibited few psychosocial predictors of poor outcome, unlike other patient populations that have been studied. Despite considerable bothersomeness at baseline, scores were low at follow-up. In this independent health sector back pain population, general health and duration of episode before consulting appeared more important to outcome than psychosocial factors

On the Centrality of Redemption: Linking the State and Credit Theories of Money Through a Financial Approach to Money

The paper presents a financial approach to monetary analysis that links the credit and state theories of money. A premise of the functional approach to money is that "money is what money does." In this approach, monetary and mercantile mechanics are conflated, which leads to the conclusion that unconvertible monetary instruments are worthless. The financial approach to money strictly separates the two mechanics and argues that major monetary disruptions occurred when the two were conflated. Monetary instruments have always been promissory notes. As such, their financial characteristics are central to their value and liquidity. One of the main financial requirements of any monetary instrument is that it be redeemable at any time. As long as this is the case, the fair value of an unconvertible monetary instrument is its face value. While the functional approach does not recognize the centrality of redemption, the paper shows that redemption plays a critical role in the state and credit views of money. Payments due to issuer and/or convertibility on demand are central to the possibility of par circulation. The paper shows that this has major implications for monetary analysis, both in terms of understanding monetary history and in terms of performing monetary analysis

Back pain outcomes in primary care following a practice improvement intervention:- a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>Back pain is one of the UK's costliest and least understood health problems, whose prevalence still seems to be increasing. Educational interventions for general practitioners on back pain appear to have had little impact on practice, but these did not include quality improvement learning, involve patients in the learning, record costs or document practice activities as well as patient outcomes.</p> <p>Methods</p> <p>We assessed the outcome of providing information about quality improvement techniques and evidence-based practice for back pain using the Clinical Value Compass. This included clinical outcomes (Roland and Morris Disability Questionnaire), functional outcomes, costs of care and patient satisfaction. We provided workshops which used an action learning approach and collected before and after data on routine practice activity from practice electronic databases. In parallel, we studied outcomes in a separate cohort of patients with acute and sub-acute non-specific back pain recruited from the same practices over the same time period. Patient data were analysed as a prospective, split-cohort study with assessments at baseline and eight weeks following the first consultation.</p> <p>Results</p> <p>Data for 1014 patients were recorded in the practice database study, and 101 patients in the prospective cohort study. We found that practice activities, costs and patient outcomes changed little after the intervention. However, the intervention was associated with a small, but statistically significant reduction in disability in female patients. Additionally, baseline disability, downheartedness, self-rated health and leg pain had small but statistically significant effects (p < 0.05) on follow-up disability scores in some subgroups.</p> <p>Conclusions</p> <p>GP education for back pain that both includes health improvement methodologies and involves patients may yield additional benefits for some patients without large changes in patterns of practice activity. The effects in this study were small and limited and the reasons for them remain obscure. However, such is the impact of back pain and its frequency of consultation in general practice that this kind of improvement methodology deserves further consideration.</p> <p>Trial registration number</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN30420389">ISRCTN30420389</a></p

Electrophysiological, cognitive and clinical profiles of at-risk mental state: the longitudinal minds in transition (MinT) study

The onset of schizophrenia is typically preceded by a prodromal period lasting several years during which sub-threshold symptoms may be identified retrospectively. Clinical interviews are currently used to identify individuals who have an ultra-high risk (UHR) of developing a psychotic illness with a view to provision of interventions that prevent, delay or reduce severity of future mental health issues. The utility of bio-markers as an adjunct in the identification of UHR individuals is not yet established. Several event-related potential measures, especially mismatch-negativity (MMN), have been identified as potential biomarkers for schizophrenia. In this 12-month longitudinal study, demographic, clinical and neuropsychological data were acquired from 102 anti-psychotic naive UHR and 61 healthy controls, of whom 80 UHR and 58 controls provided valid EEG data during a passive auditory task at baseline. Despite widespread differences between UHR and controls on demographic, clinical and neuropsychological measures, MMN and P3a did not differ between these groups. Of 67 UHR at the 12-month follow-up, 7 (10%) had transitioned to a psychotic illness. The statistical power to detect differences between those who did or did not transition was limited by the lower than expected transition rate. ERPs did not predict transition, with trends in the opposite direction to that predicted. In exploratory analysis, the strongest predictors of transition were measures of verbal memory and subjective emotional disturbance.Rebbekah J. Atkinson, W. Ross Fulham, Patricia T. Michie, Philip B. Ward, Juanita Todd, Helen Stain ... et al

Prognostic factors for perceived recovery or functional improvement in non-specific low back pain: secondary analyses of three randomized clinical trials

The objective of this study was to report on secondary analyses of a merged trial dataset aimed at exploring the potential importance of patient factors associated with clinically relevant improvements in non-acute, non-specific low back pain (LBP). From 273 predominantly male army workers (mean age 39 ± 10.5 years, range 20–56 years, 4 women) with LBP who were recruited in three randomized clinical trials, baseline individual patient factors, pain-related factors, work-related psychosocial factors, and psychological factors were evaluated as potential prognostic variables in a short-term (post-treatment) and a long-term logistic regression model (6 months after treatment). We found one dominant prognostic factor for improvement directly after treatment as well as 6 months later: baseline functional disability, expressed in Roland–Morris Disability Questionnaire scores. Baseline fear of movement, expressed in Tampa Scale for Kinesiophobia scores, had also significant prognostic value for long-term improvement. Less strongly associated with the outcome, but also included in our final models, were supervisor social support and duration of complaints (short-term model), and co-worker social support and pain radiation (long-term model). Information about initial levels of functional disability and fear-avoidance behaviour can be of value in the treatment of patient populations with characteristics comparable to the current army study population (e.g., predominantly male, physically active, working, moderate but chronic back problems). Individuals at risk for poor long-term LBP recovery, i.e., individuals with high initial level of disability and prominent fear-avoidance behaviour, can be distinguished that may need additional cognitive-behavioural treatment