Structure Constant of the Yang-Lee Edge Singularity

This paper studies the Yang-Lee singularity of the 2-dimensional Ising model on the cylinder via transfer matrix and finite-size scaling techniques. These techniques enable a measurement of the 2-point and 3-point correlations and a comparison of a measurement of a corresponding universal amplitude with a prediction for the amplitude from the (A4,A1) minimal conformal field theory.Comment: 1 figur

Approximate Bayesian Computation in State Space Models

A new approach to inference in state space models is proposed, based on approximate Bayesian computation (ABC). ABC avoids evaluation of the likelihood function by matching observed summary statistics with statistics computed from data simulated from the true process; exact inference being feasible only if the statistics are sufficient. With finite sample sufficiency unattainable in the state space setting, we seek asymptotic sufficiency via the maximum likelihood estimator (MLE) of the parameters of an auxiliary model. We prove that this auxiliary model-based approach achieves Bayesian consistency, and that - in a precise limiting sense - the proximity to (asymptotic) sufficiency yielded by the MLE is replicated by the score. In multiple parameter settings a separate treatment of scalar parameters, based on integrated likelihood techniques, is advocated as a way of avoiding the curse of dimensionality. Some attention is given to a structure in which the state variable is driven by a continuous time process, with exact inference typically infeasible in this case as a result of intractable transitions. The ABC method is demonstrated using the unscented Kalman filter as a fast and simple way of producing an approximation in this setting, with a stochastic volatility model for financial returns used for illustration

Auxiliary Likelihood-Based Approximate Bayesian Computation in State Space Models

A computationally simple approach to inference in state space models is proposed, using approximate Bayesian computation (ABC). ABC avoids evaluation of an intractable likelihood by matching summary statistics for the observed data with statistics computed from data simulated from the true process, based on parameter draws from the prior. Draws that produce a 'match' between observed and simulated summaries are retained, and used to estimate the inaccessible posterior. With no reduction to a low-dimensional set of sufficient statistics being possible in the state space setting, we define the summaries as the maximum of an auxiliary likelihood function, and thereby exploit the asymptotic sufficiency of this estimator for the auxiliary parameter vector. We derive conditions under which this approach - including a computationally efficient version based on the auxiliary score - achieves Bayesian consistency. To reduce the well-documented inaccuracy of ABC in multi-parameter settings, we propose the separate treatment of each parameter dimension using an integrated likelihood technique. Three stochastic volatility models for which exact Bayesian inference is either computationally challenging, or infeasible, are used for illustration. We demonstrate that our approach compares favorably against an extensive set of approximate and exact comparators. An empirical illustration completes the paper.Comment: This paper is forthcoming at the Journal of Computational and Graphical Statistics. It also supersedes the earlier arXiv paper "Approximate Bayesian Computation in State Space Models" (arXiv:1409.8363

Critical Excitation Spectrum of Quantum Chain With A Local 3-Spin Coupling

This article reports a measurement of the low-energy excitation spectrum along the critical line for a quantum spin chain having a local interaction between three Ising spins and longitudinal and transverse magnetic fields. The measured excitation spectrum agrees with that predicted by the (D$_4$, A$_4$) conformal minimal model under a nontrivial correspondence between translations at the critical line and discrete lattice translations. Under this correspondence, the measurements confirm a prediction that the critical line of this quantum spin chain and the critical point of the 2D 3-state Potts model are in the same universality class.Comment: 7 pages, 2 figure

Excitation Spectrum at the Yang-Lee Edge Singularity of 2D Ising Model on the Strip

At the Yang-Lee edge singularity, finite-size scaling behavior is used to measure the low-lying excitation spectrum of the Ising quantum spin chain for free boundary conditions. The measured spectrum is used to identify the CFT that describes the Yang-Lee edge singularity of the 2D Ising model for free boundary conditions.Comment: 7 pages, 1 figur

An empirical investigation of hypersexuality

The aim of this study was to investigate the nature of hypersexuality and the personality factors associated with the desire for and experience of high frequency sexual behavior. Participants in the study were 69 male and 93 female university students. Respondents reported on their desire for and experience of masturbation, oral sex, sexual intercourse, pornography, indecent phone calls or letters, prostitution, exhibitionism, voyeurism, as well as providing self-report measures which evaluated their levels of state and trait anxiety, depression, obsessive and compulsive symptoms and fear of intimacy. The results demonstrated that subjects who engaged in high-frequency voyeurism were more depressed than low-frequency voyeurs. Respondents in the high-frequency sexual deviant desire and behavior groups appeared to have more obsessive-compulsive symptoms in comparison to the low-frequency deviant sexual behavior and desire groups. Increased psychopathology was not associated with high-frequency non-deviant sexual behaviors and desires. This finding raised the question of whether labels such as sexual compulsion and addiction are merely pathologizing illegal sexual behavior

The relaxation of OH (v = 1) and OD (v = 1) by H2O and D2O at temperatures from 251 to 390 K

We report rate coefficients for the relaxation of OH(v = 1) and OD(v = 1) by H2O and D2O as a function of temperature between 251 and 390 K. All four rate coefficients exhibit a negative dependence on temperature. In Arrhenius form, the rate coefficients for relaxation (in units of 10–12 cm3 molecule–1 s–1) can be expressed as: for OH(v = 1) + H2O between 263 and 390 K: k = (2.4 ± 0.9) exp((460 ± 115)/T); for OH(v = 1) + D2O between 256 and 371 K: k = (0.49 ± 0.16) exp((610 ± 90)/T); for OD(v = 1) + H2O between 251 and 371 K: k = (0.92 ± 0.16) exp((485 ± 48)/T); for OD(v = 1) + D2O between 253 and 366 K: k = (2.57 ± 0.09) exp((342 ± 10)/T). Rate coefficients at (297 ± 1 K) are also reported for the relaxation of OH(v = 2) by D2O and the relaxation of OD(v = 2) by H2O and D2O. The results are discussed in terms of a mechanism involving the formation of hydrogen-bonded complexes in which intramolecular vibrational energy redistribution can occur at rates competitive with re-dissociation to the initial collision partners in their original vibrational states. New ab initio calculations on the H2O–HO system have been performed which, inter alia, yield vibrational frequencies for all four complexes: H2O–HO, D2O–HO, H2O–DO and D2O–DO. These data are then employed, adapting a formalism due to Troe (J. Troe, J. Chem. Phys., 1977, 66, 4758), in order to estimate the rates of intramolecular energy transfer from the OH (OD) vibration to other modes in the complexes in order to explain the measured relaxation rates—assuming that relaxation proceeds via the hydrogen-bonded complexes

Why are some people with neurological illness more resilient than others?

The current qualitative study was designed to evaluate the coping strategies of people living with a chronic progressive neurological illness and their carers. The neurological illnesses were Huntington&rsquo;s disease, motor neurone disease, multiple sclerosis and Parkinson&rsquo;s disease. Participants included 15 people who showed high levels of adjustment and 15 who showed low levels of adjustment. Participants were selected from an earlier study, to ensure that they satisfied the inclusion criteria for the current study. Interviews were completed to determine the strategies used to cope with the demands of the illness. Participants who demonstrated good adjustment were more likely to draw on social support to provide them with the resources to deal with the illness. In contrast, those who evidenced poor adjustment were more likely to draw on external supports to complete tasks for them. The implications of these findings for people with chronic neurological illnesses and their families are discussed.<br /

Erectile dysfunction and relationships : views of men with erectile dysfunction and their partners

There has been limited previous research that has examined the views of both men with erectile dysfunction (ED) and their partners on the impact of ED on their sexuality, relationship and general functioning. The current study was designed to evaluate the above variables among men with ED and their partners. Participants for the current study were 40 heterosexual men with ED and their partners. All participants completed a questionnaire that evaluated their reaction to ED, their past and current sexual activity, their sexual and relationship satisfaction as well as their levels of self-esteem and quality of life (QOL). The results demonstrated that both men with ED and their partners reported a reduction in their levels of sexual activity since the development of ED and that they wanted to seek a solution to the problem. Men with ED demonstrated lower levels of self-esteem, QOL and sexual satisfaction than their partners but there were no differences between the partners in their level of relationship satisfaction. These findings demonstrate that ED has an impact on both the man and his partner. They also indicate the importance of including the man\u27s partner in the assessment and treatment of ED. <br /

Nonverbal Behavior During Face-to-face Social Interaction in Schizophrenia

Patients with a diagnosis of schizophrenia display social cognitive deficits. However, little is known about patients’ nonverbal communication during their social encounters with others. This review identified 17 studies investigating nonverbal communication in patients’ unscripted face-to-face interactions, addressing a) nonverbal differences between patients and others, b) nonverbal behavior of the patients’ partners, c) the association between nonverbal behavior and symptoms, and d) the association between nonverbal behavior and social outcomes. Patients displayed fewer nonverbal behaviors inviting interaction, with negative symptoms exacerbating this pattern. Positive symptoms were associated with heightened nonverbal behavior. Patients’ partners changed their own nonverbal behavior in response to the patient. Reduced prosocial behaviors, inviting interaction, were associated with poorer social outcomes. The evidence suggests that patients’ nonverbal behavior, during face-to-face interaction, is influenced by patients symptoms and impacts the success of their social interactions