Dielectric and thermal relaxation in the energy landscape

We derive an energy landscape interpretation of dielectric relaxation times in undercooled liquids, comparing it to the traditional Debye and Gemant-DiMarzio-Bishop pictures. The interaction between different local structural rearrangements in the energy landscape explains qualitatively the recently observed splitting of the flow process into an initial and a final stage. The initial mechanical relaxation stage is attributed to hopping processes, the final thermal or structural relaxation stage to the decay of the local double-well potentials. The energy landscape concept provides an explanation for the equality of thermal and dielectric relaxation times. The equality itself is once more demonstrated on the basis of literature data for salol.Comment: 7 pages, 3 figures, 41 references, Workshop Disordered Systems, Molveno 2006, submitted to Philosophical Magazin

Speech Spectrum's Correlation with Speakers' Eysenck Personality Traits

The current study explored the correlation between speakers' Eysenck personality traits and speech spectrum parameters. Forty-six subjects completed the Eysenck Personality Questionnaire. They were instructed to verbally answer the questions shown on a computer screen and their responses were recorded by the computer. Spectrum parameters of /sh/ and /i/ were analyzed by Praat voice software. Formant frequencies of the consonant /sh/ in lying responses were significantly lower than that in truthful responses, whereas no difference existed on the vowel /i/ speech spectrum. The second formant bandwidth of the consonant /sh/ speech spectrum was significantly correlated with the personality traits of Psychoticism, Extraversion, and Neuroticism, and the correlation differed between truthful and lying responses, whereas the first formant frequency of the vowel /i/ speech spectrum was negatively correlated with Neuroticism in both response types. The results suggest that personality characteristics may be conveyed through the human voice, although the extent to which these effects are due to physiological differences in the organs associated with speech or to a general Pygmalion effect is yet unknown

Barriers and attitudes influencing non-engagement in a peer feedback model to inform evidence for GP appraisal

<p>Abstract</p> <p>Background</p> <p>The UK general practitioner (GP) appraisal system is deemed to be an inadequate source of performance evidence to inform a future medical revalidation process. A long-running voluntary model of external peer review in the west of Scotland provides feedback by trained peers on the standard of GP colleagues' core appraisal activities and may 'add value' in strengthening the robustness of the current system in support of revalidation. A significant minority of GPs has participated in the peer feedback model, but a clear majority has yet to engage with it. We aimed to explore the views of non-participants to identify barriers to engagement and attitudes to external peer review as a means to inform the current appraisal system.</p> <p>Methods</p> <p>We conducted semi-structured interviews with a sample of west of Scotland GPs who had yet to participate in the peer review model. A thematic analysis of the interview transcriptions was conducted using a constant comparative approach.</p> <p>Results</p> <p>13 GPs were interviewed of whom nine were males. Four core themes were identified in relation to the perceived and experienced 'value' placed on the topics discussed and their relevance to routine clinical practice and professional appraisal: 1. Value of the appraisal improvement activity. 2. Value of external peer review. 3. Value of the external peer review model and host organisation and 4. Attitudes to external peer review.</p> <p>Conclusions</p> <p>GPs in this study questioned the 'value' of participation in the external peer review model and the national appraisal system over the standard of internal feedback received from immediate work colleagues. There was a limited understanding of the concept, context and purpose of external peer review and some distrust of the host educational provider. Future engagement with the model by these GPs is likely to be influenced by policy to improve the standard of appraisal and contractual related activities, rather than a self-directed recognition of learning needs.</p

What do parents perceive are the barriers and facilitators to accessing psychological treatment for mental health problems in children and adolescents? A systematic review of qualitative and quantitative studies

A minority of children and adolescents with mental health problems access treatment. The reasons for poor rates of treatment access are not well understood. As parents are a key gatekeeper to treatment access, it is important to establish parents’ views of barriers/facilitators to accessing treatment. The aims of this study are to synthesise findings from qualitative and quantitative studies that report parents’ perceptions of barriers/facilitators to accessing treatment for mental health problems in children/adolescents. A systematic review and narrative synthesis were conducted. Forty-four studies were included in the review and were assessed in detail. Parental perceived barriers/facilitators relating to (1) systemic/structural issues; (2) views and attitudes towards services and treatment; (3) knowledge and understanding of mental health problems and the help-seeking process; and (4) family circumstances were identified. Findings highlight avenues for improving access to child mental health services, including increased provision that is free to service users and flexible to their needs, with opportunities to develop trusting, supportive relationships with professionals. Furthermore, interventions are required to improve parents’ identification of mental health problems, reduce stigma for parents, and increase awareness of how to access services

Genesis of Neuronal and Glial Progenitors in the Cerebellar Cortex of Peripuberal and Adult Rabbits

Adult neurogenesis in mammals is restricted to some brain regions, in contrast with other vertebrates in which the genesis of new neurons is more widespread in different areas of the nervous system. In the mammalian cerebellum, neurogenesis is thought to be limited to the early postnatal period, coinciding with end of the granule cell genesis and disappearance of the external granule cell layer (EGL). We recently showed that in the rabbit cerebellum the EGL is replaced by a proliferative layer called ‘subpial layer’ (SPL) which persists beyond puberty on the cerebellar surface. Here we investigated what happens in the cerebellar cortex of peripuberal rabbits by using endogenous and exogenously-administered cell proliferation antigens in association with a cohort of typical markers for neurogenesis. We show that cortical cell progenitors extensively continue to be generated herein. Surprisingly, this neurogenic process continues to a lesser extent in the adult, even in the absence of a proliferative SPL. We describe two populations of newly generated cells, involving neuronal cells and multipolar, glia-like cells. The genesis of neuronal precursors is restricted to the molecular layer, giving rise to cells immunoreactive for GABA, and for the transcription factor Pax2, a marker for GABAergic cerebellar interneuronal precursors of neuroepithelial origin that ascend through the white matter during early postnatal development. The multipolar cells are Map5+, contain Olig2 and Sox2 transcription factors, and are detectable in all cerebellar layers. Some dividing Sox2+ cells are Bergmann glia cells. All the cortical newly generated cells are independent from the SPL and from granule cell genesis, the latter ending before puberty. This study reveals that adult cerebellar neurogenesis can exist in some mammals. Since rabbits have a longer lifespan than rodents, the protracted neurogenesis within its cerebellar parenchyma could be a suitable model for studying adult nervous tissue permissiveness in mammals

Extracting key information from historical data to quantify the transmission dynamics of smallpox

<p>Abstract</p> <p>Background</p> <p>Quantification of the transmission dynamics of smallpox is crucial for optimizing intervention strategies in the event of a bioterrorist attack. This article reviews basic methods and findings in mathematical and statistical studies of smallpox which estimate key transmission parameters from historical data.</p> <p>Main findings</p> <p>First, critically important aspects in extracting key information from historical data are briefly summarized. We mention different sources of heterogeneity and potential pitfalls in utilizing historical records. Second, we discuss how smallpox spreads in the absence of interventions and how the optimal timing of quarantine and isolation measures can be determined. Case studies demonstrate the following. (1) The upper confidence limit of the 99th percentile of the incubation period is 22.2 days, suggesting that quarantine should last 23 days. (2) The highest frequency (61.8%) of secondary transmissions occurs 3–5 days after onset of fever so that infected individuals should be isolated before the appearance of rash. (3) The U-shaped age-specific case fatality implies a vulnerability of infants and elderly among non-immune individuals. Estimates of the transmission potential are subsequently reviewed, followed by an assessment of vaccination effects and of the expected effectiveness of interventions.</p> <p>Conclusion</p> <p>Current debates on bio-terrorism preparedness indicate that public health decision making must account for the complex interplay and balance between vaccination strategies and other public health measures (e.g. case isolation and contact tracing) taking into account the frequency of adverse events to vaccination. In this review, we summarize what has already been clarified and point out needs to analyze previous smallpox outbreaks systematically.</p