Autistic traits modulate frontostriatal connectivity during processing of rewarding faces

Deficits in facial mimicry have been widely reported in autism. Some studies have suggested that these deficits are restricted to spontaneous mimicry and do not extend to volitional mimicry. We bridge these apparently inconsistent observations, by testing the impact of reward value on neural indices of mimicry, and how autistic traits modulate this impact. Neutral faces were conditioned with high and low reward. Subsequently, functional connectivity between the ventral striatum (VS) and inferior frontal gyrus (IFG) was measured whilst neurotypical adults (n = 30) watched happy expressions made by these conditioned faces. We found greater VS-IFG connectivity in response to high-reward vs. low-reward happy faces. This difference was negatively proportional to autistic traits, suggesting that reduced spontaneous mimicry of social stimuli seen in autism, maybe related to a failure in the modulation of the mirror system by the reward system rather than a circumscribed deficit in the mirror system

Propagation of Correlations in Quantum Lattice Systems

We provide a simple proof of the Lieb-Robinson bound and use it to prove the existence of the dynamics for interactions with polynomial decay. We then use our results to demonstrate that there is an upper bound on the rate at which correlations between observables with separated support can accumulate as a consequence of the dynamics.Comment: 10 page

The subgroup growth spectrum of virtually free groups

For a finitely generated group $\Gamma$ denote by $\mu(\Gamma)$ the growth coefficient of $\Gamma$, that is, the infimum over all real numbers $d$ such that $s_n(\Gamma)<n!^d$. We show that the growth coefficient of a virtually free group is always rational, and that every rational number occurs as growth coefficient of some virtually free group. Moreover, we describe an algorithm to compute $\mu$

Isolated Eigenvalues of the Ferromagnetic Spin-J XXZ Chain with Kink Boundary Conditions

We investigate the low-lying excited states of the spin J ferromagnetic XXZ chain with Ising anisotropy Delta and kink boundary conditions. Since the third component of the total magnetization, M, is conserved, it is meaningful to study the spectrum for each fixed value of M. We prove that for J>= 3/2 the lowest excited eigenvalues are separated by a gap from the rest of the spectrum, uniformly in the length of the chain. In the thermodynamic limit, this means that there are a positive number of excitations above the ground state and below the essential spectrum

A quantum central limit theorem for non-equilibrium systems: Exact local relaxation of correlated states

We prove that quantum many-body systems on a one-dimensional lattice locally relax to Gaussian states under non-equilibrium dynamics generated by a bosonic quadratic Hamiltonian. This is true for a large class of initial states - pure or mixed - which have to satisfy merely weak conditions concerning the decay of correlations. The considered setting is a proven instance of a situation where dynamically evolving closed quantum systems locally appear as if they had truly relaxed, to maximum entropy states for fixed second moments. This furthers the understanding of relaxation in suddenly quenched quantum many-body systems. The proof features a non-commutative central limit theorem for non-i.i.d. random variables, showing convergence to Gaussian characteristic functions, giving rise to trace-norm closeness. We briefly relate our findings to ideas of typicality and concentration of measure.Comment: 27 pages, final versio

Gross Domestic Product (GDP) and productivity of schizophrenia trials: an ecological study

The 5000 randomised controlled trials (RCTs) in the Cochrane Schizophrenia Group's database affords an opportunity to research for variables related to the differences between nations of their output of schizophrenia trials. Ecological study – investigating the relationship between four economic/demographic variables and number of schizophrenia RCTs per country. The variable with closest correlation was used to predict the expected number of studies. GDP closely correlated with schizophrenia trial output, with 76% of the total variation about the Y explained by the regression line (r = 0.87, 95% CI 0.79 to 0.92, r2 = 0.76). Many countries have a strong tradition of schizophrenia trials, exceeding their predicted output. All nations with no identified trial output had GDPs that predicted zero trial activity. Several nations with relatively small GDPs are, nevertheless, highly productive of trials. Some wealthy countries seem either not to have produced the expected number of randomised trials or not to have disseminated them to the English-speaking world. This hypothesis-generating study could not investigate causal relationships, but suggests, that for those seeking all relevant studies, expending effort searching the scientific literature of Germany, Italy, France, Brazil and Japan may be a good investment

Correlations, spectral gap, and entanglement in harmonic quantum systems on generic lattices

We investigate the relationship between the gap between the energy of the ground state and the first excited state and the decay of correlation functions in harmonic lattice systems. We prove that in gapped systems, the exponential decay of correlations follows for both the ground state and thermal states. Considering the converse direction, we show that an energy gap can follow from algebraic decay and always does for exponential decay. The underlying lattices are described as general graphs of not necessarily integer dimension, including translationally invariant instances of cubic lattices as special cases. Any local quadratic couplings in position and momentum coordinates are allowed for, leading to quasi-free (Gaussian) ground states. We make use of methods of deriving bounds to matrix functions of banded matrices corresponding to local interactions on general graphs. Finally, we give an explicit entanglement-area relationship in terms of the energy gap for arbitrary, not necessarily contiguous regions on lattices characterized by general graphs.Comment: 26 pages, LaTeX, published version (figure added

A Multi-Dimensional Lieb-Schultz-Mattis Theorem

For a large class of finite-range quantum spin models with half-integer spins, we prove that uniqueness of the ground state implies the existence of a low-lying excited state. For systems of linear size L, of arbitrary finite dimension, we obtain an upper bound on the excitation energy (i.e., the gap above the ground state) of the form (C\log L)/L. This result can be regarded as a multi-dimensional Lieb-Schultz-Mattis theorem and provides a rigorous proof of a recent result by Hastings.Comment: final versio

Increasing the acceptability and rates of organ donation among minority ethnic groups: a programme of observational and evaluative research on Donation, Transplantation and Ethnicity (DonaTE)

Background: Black, Asian and minority ethnic (BAME) groups have a high need for organ transplantation but deceased donation is low. This restricts the availability of well-matched organs and results in relatively long waiting times for transplantation, with increased mortality risks. Objective: To identify barriers to organ donor registration and family consent among the BAME population, and to develop and evaluate a training intervention to enhance communication with ethnic minority families and identify impacts on family consent. Methods: Three-phase programme comprising (1) community-based research involving two systematic reviews examining attitudes and barriers to organ donation and effective interventions followed by 22 focus groups with minority ethnic groups; (2) hospital-based research examining staff practices and influences on family consent through ethics discussion groups (EDGs) with staff, a study on intensive care units (ICUs) and interviews with bereaved ethnic minority families; and (3) development and evaluation of a training package to enhance cultural competence among ICU staff. Setting: Community focus group study in eight London boroughs with high prevalence of ethnic minority populations. Hospital studies at five NHS hospital trusts (three in London and two in Midlands). Participants: (1) Community studies: 228 focus group participants; (2) hospital studies: 35 nurses, 28 clinicians, 19 hospital chaplains, 25 members of local Organ Donation Committees, 17 bereaved family members; and (3) evaluation: 66 health professionals. Data sources: Focus groups with community residents, systematic reviews, qualitative interviews and observation in ICUs, EDGs with ICU staff, bereaved family interviews and questionnaires for trial evaluation. Review methods: Systematic review and narrative synthesis. Results: (1) Community studies: Organ Donor Register – different ethnic/faith and age groups were at varying points on the ‘pathway’ to organ donor registration, with large numbers lacking knowledge and remaining at a pre-contemplation stage. Key attitudinal barriers were uncertainties regarding religious permissibility, bodily concerns, lack of trust in health professionals and little priority given to registration, with the varying significance of these factors varying by ethnicity/faith and age. National campaigns focusing on ethnic minorities have had limited impact, whereas characteristics of effective educational interventions are being conducted in a familiar environment; addressing the groups’ particular concerns; delivery by trained members of the lay community; and providing immediate access to registration. Interventions are also required to target those at specific stages of the donation pathway. (2) Hospital studies: family consent to donation – many ICU staff, especially junior nurses, described a lack of confidence in communication and supporting ethnic minority families, often reflecting differences in emotional expression, faith and cultural beliefs, and language difficulties. The continuing high proportion of family donation discussions that take place without the collaboration of a specialist nurse for organ donation (SNOD) reflected consultants’ views of their own role in family consent to donation, a lack of trust in SNODs and uncertainties surrounding controlled donations after circulatory (or cardiac) death. Hospital chaplains differed in their involvement in ICUs, reflecting their availability/employment status, personal interests and the practices of ICU staff. (3) Evaluation: professional development package – a digital versatile disk-based training package was developed to promote confidence and skills in cross-cultural communication (available at: www.youtube.com/watch?v=ueaR6XYkeVM&feature=youtu.be). Initial evaluation produced positive feedback and significant affirmative attitudinal change but no significant difference in consent rate over the short follow-up period with requirements for longer-term evaluation. Limitations: Participants in the focus group study were mainly first-generation migrants of manual socioeconomic groups. It was not permitted to identify non-consenting families for interview with data regarding the consent process were therefore limited to consenting families. Conclusions: The research presents guidance for the effective targeting of donation campaigns focusing on minority ethnic groups and provides the first training package in cultural competence in the NHS. Future work: Greater evaluation is required of community interventions in the UK to enhance knowledge of effective practice and analysis of the experiences of non-consenting ethnic minority families. Funding: The National Institute for Health Research Programme Grants for Applied Research programme