Neutral Evolution as Diffusion in phenotype space: reproduction with mutation but without selection

The process of `Evolutionary Diffusion', i.e. reproduction with local mutation but without selection in a biological population, resembles standard Diffusion in many ways. However, Evolutionary Diffusion allows the formation of local peaks with a characteristic width that undergo drift, even in the infinite population limit. We analytically calculate the mean peak width and the effective random walk step size, and obtain the distribution of the peak width which has a power law tail. We find that independent local mutations act as a diffusion of interacting particles with increased stepsize.Comment: 4 pages, 2 figures. Paper now representative of published articl

Kinetic growth walks on complex networks

Kinetically grown self-avoiding walks on various types of generalized random networks have been studied. Networks with short- and long-tailed degree distributions $P(k)$ were considered ($k$, degree or connectivity), including scale-free networks with $P(k) \sim k^{-\gamma}$. The long-range behaviour of self-avoiding walks on random networks is found to be determined by finite-size effects. The mean self-intersection length of non-reversal random walks, , scales as a power of the system size $N$: $ \sim N^{\beta}$, with an exponent $\beta = 0.5$ for short-tailed degree distributions and $\beta < 0.5$ for scale-free networks with $\gamma < 3$. The mean attrition length of kinetic growth walks, , scales as $\sim N^{\alpha}$, with an exponent $\alpha$ which depends on the lowest degree in the network. Results of approximate probabilistic calculations are supported by those derived from simulations of various kinds of networks. The efficiency of kinetic growth walks to explore networks is largely reduced by inhomogeneity in the degree distribution, as happens for scale-free networks.Comment: 10 pages, 8 figure

Oxygen cost of dynamic or isometric exercise relative to recruited muscle mass

BACKGROUND: Oxygen cost of different muscle actions may be influenced by different recruitment and rate coding strategies. The purpose of this study was to account for these strategies by comparing the oxygen cost of dynamic and isometric muscle actions relative to the muscle mass recruited via surface electrical stimulation of the knee extensors. METHODS: Comparisons of whole body pulmonary Δ [Formula: see text] O(2 )were made in seven young healthy adults (1 female) during 3 minutes of dynamic or isometric knee extensions, both induced by surface electrical stimulation. Recruited mass was quantified in T(2 )weighted spin echo magnetic resonance images. RESULTS: The Δ [Formula: see text] O(2 )for dynamic muscle actions, 242 ± 128 ml • min(-1 )(mean ± SD) was greater (p = 0.003) than that for isometric actions, 143 ± 99 ml • min(-1). Recruited muscle mass was also greater (p = 0.004) for dynamic exercise, 0.716 ± 282 versus 0.483 ± 0.139 kg. The rate of oxygen consumption per unit of recruited muscle ([Formula: see text]) was similar in dynamic and isometric exercise (346 ± 162 versus 307 ± 198 ml • kg(-1 )• min(-1); p = 0.352), but the [Formula: see text] calculated relative to initial knee extensor torque was significantly greater during dynamic exercise 5.1 ± 1.5 versus 3.6 ± 1.6 ml • kg(-1 )• Nm(-1 )• min(-1 )(p = 0.019). CONCLUSION: These results are consistent with the view that oxygen cost of dynamic and isometric actions is determined by different circumstances of mechanical interaction between actin and myosin in the sarcomere, and that muscle recruitment has only a minor role

Signatures of quantum effects on radiation reaction in laser-electron-beam collisions

Two signatures of quantum effects on radiation reaction in the collision of a GeV electron beam with a high intensity (>3×1020Wcm-2]]>) laser pulse have been considered. We show that the decrease in the average energy of the electron beam may be used to measure the Gaunt factor for synchrotron emission. We derive an equation for the evolution of the variance in the energy of the electron beam in the quantum regime, i.e. quantum efficiency parameter . We show that the evolution of the variance may be used as a direct measure of the quantum stochasticity of the radiation reaction and determine the parameter regime where this is observable. For example, stochastic emission results in a 25% increase in the standard deviation of the energy spectrum of a GeV electron beam, 1 fs after it collides with a laser pulse of intensity 1021W cm-2. This effect should therefore be measurable using current high-intensity laser systems

Localism: a planning panacea?

© 2019 Liverpool University Press. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.3828/tpr.2019.31It has been observed that there is a 'global trend' towards devolution of power from national governments to regional and local authorities, and planning is one of the activities often devolved. In England, the UK government has since 2011 gone further and, it claims, devolved planning powers to the community level. The introduction of a new form of statutory planning - neighbourhood planning - was heralded by the UK government as an embodiment of their commitment to 'localism', representing a shift from top-down to bottom-up control in the English planning system. This Policy and Practice explores some of the tensions inherent in localism as exemplified through the practical implementation of neighbourhood planning.Peer reviewedFinal Accepted Versio

Random walk on the range of random walk

We study the random walk X on the range of a simple random walk on ℤ d in dimensions d≥4. When d≥5 we establish quenched and annealed scaling limits for the process X, which show that the intersections of the original simple random walk path are essentially unimportant. For d=4 our results are less precise, but we are able to show that any scaling limit for X will require logarithmic corrections to the polynomial scaling factors seen in higher dimensions. Furthermore, we demonstrate that when d=4 similar logarithmic corrections are necessary in describing the asymptotic behavior of the return probability of X to the origin

The scaling limit of the incipient infinite cluster in high-dimensional percolation. II. Integrated super-Brownian excursion

For independent nearest-neighbour bond percolation on Z^d with d >> 6, we prove that the incipient infinite cluster's two-point function and three-point function converge to those of integrated super-Brownian excursion (ISE) in the scaling limit. The proof is based on an extension of the new expansion for percolation derived in a previous paper, and involves treating the magnetic field as a complex variable. A special case of our result for the two-point function implies that the probability that the cluster of the origin consists of n sites, at the critical point, is given by a multiple of n^{-3/2}, plus an error term of order n^{-3/2-\epsilon} with \epsilon >0. This is a strong statement that the critical exponent delta is given by delta =2.Comment: 56 pages, 3 Postscript figures, in AMS-LaTeX, with graphicx, epic, and xr package

The Relationship between Therapeutic Alliance and Service User Satisfaction in Mental Health Inpatient Wards and Crisis House Alternatives: A Cross-Sectional Study

Background Poor service user experiences are often reported on mental health inpatient wards. Crisis houses are an alternative, but evidence is limited. This paper investigates therapeutic alliances in acute wards and crisis houses, exploring how far stronger therapeutic alliance may underlie greater client satisfaction in crisis houses. Methods and Findings Mixed methods were used. In the quantitative component, 108 crisis house and 247 acute ward service users responded to measures of satisfaction, therapeutic relationships, informal peer support, recovery and negative events experienced during the admission. Linear regressions were conducted to estimate the association between service setting and measures, and to model the factors associated with satisfaction. Qualitative interviews exploring therapeutic alliances were conducted with service users and staff in each setting and analysed thematically. Results We found that therapeutic alliances, service user satisfaction and informal peer support were greater in crisis houses than on acute wards, whilst self-rated recovery and numbers of negative events were lower. Adjusted multivariable analyses suggest that therapeutic relationships, informal peer support and negative experiences related to staff may be important factors in accounting for greater satisfaction in crisis houses. Qualitative results suggest factors that influence therapeutic alliances include service user perceptions of basic human qualities such as kindness and empathy in staff and, at service level, the extent of loss of liberty and autonomy. Conclusions and Implications We found that service users experience better therapeutic relationships and higher satisfaction in crisis houses compared to acute wards, although we cannot exclude the possibility that differences in service user characteristics contribute to this. This finding provides some support for the expansion of crisis house provision. Further research is needed to investigate why acute ward service users experience a lack of compassion and humanity from ward staff and how this could be changed

Personal Recovery in People With a Psychotic Disorder:A Systematic Review and Meta-Analysis of Associated Factors

Background: Personal recovery (PR) is a subjective, multidimensional concept, and quantitative research using PR as an outcome is rapidly increasing. This systematic review is intended to support the design of interventions that contribute to PR in psychotic disorders, by providing an overview of associated factors and their weighted importance to PR: clinical factors, social factors, and socio-demographic characteristics are included, and factors related to the concept of PR (organized into CHIME dimensions). Methods: A systematic literature search was conducted from inception to March 2020. Quantitative studies that had used a validated questionnaire assessing the concept of PR were included. Mean effect sizes for the relationship between PR-scale total scores and related factors were calculated using meta-analyses. Sources of heterogeneity were examined using meta-regression tests. Results: Forty-six studies, that used (a total of) eight PR measures, showed that in clinical factors, affective symptoms had a medium negative association with PR-scale total scores (r = −0.44, 95%CI −0.50 to −0.37), while positive, negative and general symptoms had small negative correlations. No association was found with neuro-cognition. Social factors (support, work and housing, and functioning) showed small positive correlations. Gender and age differences had barely been researched. Large associations were found for PR-scale total scores with the CHIME dimensions hope (r = 0.56, 95%CI 0.48–0.63), meaning in life (r = 0.48, 95%CI 0.38–0.58) and empowerment (r = 0.53, 95%CI 0.42–0.63); while medium associations were found with connectedness (r = 0.34, 95%CI 0.43–0.65) and identity (r = 0.43, 95%CI 0.35–0.50). Levels of heterogeneity were high, sources included: the variety of PR measures, variations in sample characteristics, publication bias, variations in outcome measures, and cultural differences. Discussion: Most interventions in mental healthcare aim to reduce symptoms and improve functioning. With regard to stimulating PR, these interventions may benefit from also focusing on enhancing hope, empowerment, and meaning in life. The strength of these findings is limited by the challenges of comparing separate CHIME dimensions with questionnaires assessing the concept of PR, and by the high levels of heterogeneity observed. Future research should focus on the interaction between elements of PR and clinical and social factors over time

Self-hypnosis for intrapartum pain management in pregnant nulliparous women: a randomised controlled trial of clinical effectiveness

Objective: (Primary) To establish the effect of antenatal group self-hypnosis for nulliparous women on intra-partum epidural use. Design: Multi-method randomised control trial (RCT). Setting: Three NHS Trusts. Population: Nulliparous women not planning elective caesarean, without medication for hypertension and without psychological illness. Methods: Randomisation at 28–32 weeks’ gestation to usual care, or to usual care plus brief self-hypnosis training (two × 90-minute groups at around 32 and 35 weeks’ gestation; daily audio self-hypnosis CD). Follow up at 2 and 6 weeks postnatal. Main outcome measures: Primary: epidural analgesia. Secondary: associated clinical and psychological outcomes; cost analysis. Results: Six hundred and eighty women were randomised. There was no statistically significant difference in epidural use: 27.9% (intervention), 30.3% (control), odds ratio (OR) 0.89 [95% confidence interval (CI): 0.64–1.24], or in 27 of 29 pre-specified secondary clinical and psychological outcomes. Women in the intervention group had lower actual than anticipated levels of fear and anxiety between baseline and 2 weeks post natal (anxiety: mean difference −0.72, 95% CI −1.16 to −0.28, P = 0.001); fear (mean difference −0.62, 95% CI −1.08 to −0.16, P = 0.009) [Correction added on 7 July 2015, after first online publication: ‘Mean difference’ replaced ‘Odds ratio (OR)’ in the preceding sentence.]. Postnatal response rates were 67% overall at 2 weeks. The additional cost in the intervention arm per woman was £4.83 (CI −£257.93 to £267.59). Conclusions: Allocation to two-third-trimester group self-hypnosis training sessions did not significantly reduce intra-partum epidural analgesia use or a range of other clinical and psychological variables. The impact of women's anxiety and fear about childbirth needs further investigation