Tunneling and delocalization in hydrogen bonded systems: a study in position and momentum space

Novel experimental and computational studies have uncovered the proton momentum distribution in hydrogen bonded systems. In this work, we utilize recently developed open path integral Car-Parrinello molecular dynamics methodology in order to study the momentum distribution in phases of high pressure ice. Some of these phases exhibit symmetric hydrogen bonds and quantum tunneling. We find that the symmetric hydrogen bonded phase possesses a narrowed momentum distribution as compared with a covalently bonded phase, in agreement with recent experimental findings. The signatures of tunneling that we observe are a narrowed distribution in the low-to-intermediate momentum region, with a tail that extends to match the result of the covalently bonded state. The transition to tunneling behavior shows similarity to features observed in recent experiments performed on confined water. We corroborate our ice simulations with a study of a particle in a model one-dimensional double well potential that mimics some of the effects observed in bulk simulations. The temperature dependence of the momentum distribution in the one-dimensional model allows for the differentiation between ground state and mixed state tunneling effects.Comment: 14 pages, 13 figure

The collectivity of British alcohol consumption trends across different temporal processes : a quantile age‐period‐cohort analysis

Background and aims UK alcohol consumption per capita has fallen by 18% since 2004 while the alcohol‐specific death rate has risen by 6%. Inconsistent consumption trends across the population may explain this. Drawing on the theory of the collectivity of drinking cultures and age‐period‐cohort analyses, we tested whether consumption trends are consistent across lighter and heavier drinkers for three temporal processes: (i) the life course, (ii) calendar time, (iii) successive birth cohorts. Design Sex‐specific quantile age‐period‐cohort regressions using repeat cross‐sectional survey data. Setting Great Britain, 1984‐2011. Participants Adult (18+) drinkers responding to 17 waves of the General Lifestyle Survey (total N=175,986). Measurements Dependent variable: The 10th, 25th, 50th, 75th, 90th, 95th and 99th quantiles of the logged weekly alcohol consumption distribution (excluding abstainers). Independent variables: seven age groups (18‐24, 25‐34 … 65‐74, 75+), five time periods (1984‐1988 … 2002‐2006, 2008‐2011) and 16 five‐year birth cohorts (1915‐1919 … 1990‐1994). Additional control variables: ethnicity and UK country. Findings Within age, period and cohort trends, changes in consumption were not consistently in the same direction at different quantiles of the consumption distribution. When they were, the scale of change sometimes differed between quantiles. For example, consumption among women decreased by 18% (CI95: ‐32% ‐ ‐2%) but increased by 11% (CI95: 2% ‐ 21%) at the median and by 28% (CI95: 19%‐38%) at the 99th quantile, implying consumption fell among lighter drinkers and rose among heavier drinkers. This type of polarised trend also occurred between 1984‐1988 and 1996‐2000 for men and women. Age trends showed collectivity but cohort trends showed a mixture of collectivity and polarisation. Conclusions Countervailing alcohol consumption and alcohol‐related harm trends in the UK may be explained by lighter and heavier drinkers having different period and cohort trends as well as by the presence of cohort trends that mean consumption may rise in some age groups while falling in others

The quantum algebra of superspace

We present the complete set of $N=1$, $D=4$ quantum algebras associated to massive superparticles. We obtain the explicit solution of these algebras realized in terms of unconstrained operators acting on the Hilbert space of superfields. These solutions are expressed using the chiral, anti-chiral and tensorial projectors which define the three irreducible representations of the supersymmetry on the superfields. In each case the space-time variables are non-commuting and their commutators are proportional to the internal angular momentum of the representation. The quantum algebra associated to the chiral or the anti-chiral projector is the one obtained by the quantization of the Casalbuoni-Brink-Schwarz (superspin 0) massive superparticle. We present a new superparticle action for the (superspin 1/2) case and show that their wave functions are the ones associated to the irreducible tensor multiplet.Comment: 20 pages;changes in the nomenclatur

Housing prices and multiple employment nodes: is the relationship nonmonotonic?

Standard urban economic theory predicts that house prices will decline with distance from the central business district. Empirical results have been equivocal, however. Disjoints between theory and empirics may be due to a nonmonotonic relationship between house prices and access to employment arising from the negative externalities associated with proximity to multiple centres of employment. Based on data from Glasgow (Scotland), we use gravity-based measures of accessibility estimated using a flexible functional form that allows for nonmonotonicity. The results are thoroughly tested using recent advances in spatial econometrics. We find compelling evidence of a nonmonotonic effect in the accessibility measure and discuss the implications for planning and housing policy

Environmental Clustering of New Zealand Dairy Herds

Previous studies have found that milk yield (a proxy for feeding level) and temperature-humidity index (THI) are important factors in explaining genotype x environment (G x E) interactions, indicating differences between the abilities of genotypes to forage or consume concentrates effectively or to cope with thermal stress (Ravagnolo and Misztal, 2000; Zwald et al., 2003). The objective of this study was to quantify and cluster (CL) herd environments within New Zealand (NZ) based on production levels, a summer heat load index (HLI) and geographical location

The impact of increasing the United Kingdom national minimum wage on self‐reported health

There is a growing but mixed literature on the health effects of minimum wages. If minimum wage changes have a statistically significant impact on health, this suggests health effects should be incorporated into cost-benefit analyses to capture wider policy impacts. Whilst most existing UK based literature examines the introduction of a minimum wage, this paper exploits the 2016, 2017 and 2018 UK National Minimum Wage (NMW) increases as natural experiments using a series of difference-in-differences models. Short Form-12 (SF-12) mental and physical component summary scores are used as dependent variables. In the base case and all sensitivity analyses, the estimated impact of NMW increases on mental and physical health are insignificant. The policy implication is that health effects should not be included in cost-benefit analyses examining the NMW

Bayes-optimal inverse halftoning and statistical mechanics of the Q-Ising model

On the basis of statistical mechanics of the Q-Ising model, we formulate the Bayesian inference to the problem of inverse halftoning, which is the inverse process of representing gray-scales in images by means of black and white dots. Using Monte Carlo simulations, we investigate statistical properties of the inverse process, especially, we reveal the condition of the Bayes-optimal solution for which the mean-square error takes its minimum. The numerical result is qualitatively confirmed by analysis of the infinite-range model. As demonstrations of our approach, we apply the method to retrieve a grayscale image, such as standard image `Lenna', from the halftoned version. We find that the Bayes-optimal solution gives a fine restored grayscale image which is very close to the original.Comment: 13pages, 12figures, using elsart.cl

Proteomic profiling reveals sub proteomes of the human placenta

Proteomic characterisation of the placenta has largely been focused on effect of disease, anatomical features or specific cell types. We describe an unbiased proteomic mapping analysis to investigate how the placental proteome changes throughout the organ. A transverse slice of a human placenta was sectioned into 1 × 1cm samples. Sections were analysed using label free proteomics. Analysis revealed two distinct sub-proteomes that did not have anatomical significance. One had a muscular proteome and the other had distinct immunomodulation functions. Chorionic plate enriched proteins highlighted the fetal tissues high energy requirements whilst mechanisms of the decidua observed included modulation of cortisone levels

Tinnitus groups – a model of social support and social connectedness from peer interaction

Tinnitus is a chronic condition for which there is no medical treatment. Tinnitus groups are a widely available resource for people with tinnitus. Objectives: Our objectives were to explore the active ingredients of tinnitus support groups in terms of their mechanisms for providing support, the contextual factors that elicit such mechanisms, and the outcomes in terms of coping enhancement. Design: We adopted a pluralist and iterative approach informed by the realist evaluation method. Methods: We conducted ethnographic data generation at tinnitus support groups involving observations (n = 160), focus groups (n = 130), and individual interviews (n = 20). Inductive analyses were conducted following the constant comparison method of grounded theory. We then interrogated the inductive themes to identify evidence of Contexts, Mechanisms, and Outcomes. We then produced a model which was tested in a survey of tinnitus group members (n = 65) in effect providing large-scale respondent validation of the data-driven model created through our inductive analysis. Results: We identified that tinnitus groups can facilitate social connectedness between group members. This experience appeared to build resilience among those experiencing tinnitus-related distress. Groups also played a role in building a sense of control related to knowledge and information sharing. Additionally, we identified risks associated with not accessing social support in a group environment. Conclusions: Our findings contribute to the growing understanding of the power of social connectedness as building shared social identity when living with tinnitus. Statement of contribution What is already known on this subject? Tinnitus is a prevalent condition with approximately 10–15% of the population experiencing a spontaneous sound without obvious source. Tinnitus is an invisible health and chronic condition. People with tinnitus experience high levels of distress, anxiety, and depression. Group support is beneficial to people with many health problems. What does this study add? This study describes the mechanisms by which tinnitus support groups can support coping in tinnitus. This is the first study to comprehensively explore the views of those who attend tinnitus groups. The study identifies the key features of support groups that facilitate social connectedness among group members. The most valued features of groups are the knowledge and information provided, the sense of belonging communicated to group members, and the creation and maintenance of a sense of hope towards the tinnitus. This study contributes new insights to both the tinnitus field and adds to the literature on support groups in health