Cooperative mixing induced surface roughening in bilayer metals: a possible novel surface damage mechanism

Molecular dynamics simulations have been used to study a collective atomic transport phenomenon by repeated Ar$^+$ irradiations in the Ti/Pt interfacial system. The ion-induced injection of surface atoms to the bulk, the ejection of bulk atoms to the top layers together with surface erosion is strongly enhanced by interfacial mixing. This process leads to a dense interfacial material, and broadening of the interface region. The process scales with the relative difference of the atomic masses. We find that surface roughening and interfacial mixing is strongly coupled via an enhanced counterflow material transport normal to the surface which might be a novel surface damage mechanism. This cooperative phenomenon is active when the bilayer system is subjected to a high dose ion irradiation (multiple ion irradiations) and leads to surface cavity growth.Comment: 6 pages, 6 figures. accepted in Nucl. Instrum. Meth.

Prevalence and measurement of anxiety in samples of patients with heart failure

© 2016 Wolters Kluwer Health, Inc. Objectives: Rates of anxiety in patients with heart failure (HF) vary widely, and not all assessment instruments used in this patient population are appropriate. It is timely to consolidate the evidence base and establish the prevalence and variance of anxiety in HF samples. Methods: A systematic review, meta-analysis, and meta-regression were conducted to identify the prevalence, variance, and measurement of anxiety in patients with HF. Results: A total of 14,367 citations were identified, with 73 studies meeting inclusion criteria. A random effects pooled prevalence of 13.1% (95% confidence interval [CI], 9.25%-16.86%) for anxiety disorders, 28.79% (95% CI, 23.30%-34.29) for probable clinically significant anxiety, and 55.5% (95% CI, 48.08%-62.83%) for elevated symptoms of anxiety was identified. Rates of anxiety were highest when measured using the Brief Symptom Scale-Anxiety scale (72.3%) and lowest when measured using the Generalised Anxiety Disorder-7 (6.3%). Conclusion: Many patients with HF would benefit if screened for anxiety and treated. The conceptualization and measurement of anxiety accounted for most variance in prevalence rates. The Generalised Anxiety Disorder-7 or the Hospital Anxiety and Depression Scale appear to be the most appropriate instruments for this clinical population, with evidence to suggest they can discriminate between depression and anxiety, omit somatic items that may contaminate identification of anxiety in a population with physical comorbidities, and provide thresholds with which to differentiate patients and target treatments. Although there are limitations with the collation of diverse measurement methods, the current review provides researchers and clinicians with a more granular knowledge of prevalence estimates of anxiety in a population of HF patients.The research was funded through an interdisciplinary doctoral studentship jointly funded by the Medical Research Council and the Economics and Social Research Council

Dilatonic current-carrying cosmic strings

We investigate the nature of ordinary cosmic vortices in some scalar-tensor extensions of gravity. We find solutions for which the dilaton field condenses inside the vortex core. These solutions can be interpreted as raising the degeneracy between the eigenvalues of the effective stress-energy tensor, namely the energy per unit length U and the tension T, by picking a privileged spacelike or timelike coordinate direction; in the latter case, a phase frequency threshold occurs that is similar to what is found in ordinary neutral current-carrying cosmic strings. We find that the dilaton contribution for the equation of state, once averaged along the string worldsheet, vanishes, leading to an effective Nambu-Goto behavior of such a string network in cosmology, i.e. on very large scales. It is found also that on small scales, the energy per unit length and tension depend on the string internal coordinates in such a way as to permit the existence of centrifugally supported equilibrium configuration, also known as vortons, whose stability, depending on the very short distance (unknown) physics, can lead to catastrophic consequences on the evolution of the Universe.Comment: 10 pages, ReVTeX, 2 figures, minor typos corrected. This version to appear in Phys. Rev.

Secondary Physical Education Teachers’ Perceptions of Adolescent Females’ Cardiovascular Fitness

Cardiovascular fitness levels in physical education have decreased for males and females in an inner-city high school, with female cardiovascular fitness decreasing the most. Cardiovascular fitness is important because participating in cardio exercises decreases health issues such as obesity and cardio problems. The purpose of this qualitative research study was to explore the views of teachers regarding low cardiovascular fitness among adolescent females in physical education and how a professional development could help teachers to address the problem. Bandura’s social learning theory was used as the study’s conceptual framework. Semistructured and open-ended interview questions were used to collect data from 6 veteran PE teachers to address the research questions regarding teachers’ experiences in promoting cardiovascular exercises, levels of participation in cardiovascular exercises, and perceptions of professional development to help ameliorate the problem. Participant responses to the open-ended interview questions were analyzed by coding common words to create categories to develop themes. Qualitative findings revealed that participants started to notice low cardiovascular endurance in 9th grade, that professional development was not geared towards improving female adolescent activities nor assisting PE teachers in how to model these. A professional development, via the proposed project, was developed that will provide activities that can be used by both new and seasoned physical education teachers. Social change will occur in that implementation of the ideas shared in project may lead to a healthier and physically active lifestyle when students reach adulthood

Commensurate Itinerant Antiferromagnetism in BaFe2As2: 75As-NMR Studies on a Self-Flux Grown Single Crystal

We report results of 75As nuclear magnetic resonance (NMR) experiments on a self-flux grown single crystal of BaFe2As2. A first-order antiferromagnetic (AF) transition near 135 K was detected by the splitting of NMR lines, which is accompanied by simultaneous structural transition as evidenced by a sudden large change of the electric field gradient tensor at the As site. The NMR results lead almost uniquely to the stripe spin structure in the AF phase. The data of spin-lattice relaxation rate indicate development of anisotropic spin fluctuations of the stripe-type with decreasing temperature in the paramagnetic phase.Comment: 7 pages, 7 figures, accepted for publication in J. Phys. Soc. Jp

Establishing and sustaining high-quality services for people with young onset dementia: The perspective of senior service providers and commissioners

OBJECTIVES: We aimed to understand the facilitators to developing and sustaining high-quality services for people with young onset dementia (YOD) and their families/supporters. DESIGN: This qualitative study used semi-structured interviews with commissioners and service managers, analyzed using inductive thematic analysis. SETTING: A purposive sample of providers was selected from diverse areas and contrasting YOD services. PARTICIPANTS: Eighteen senior staff from YOD services and two dementia service commissioners took part. MEASUREMENTS: For commissioners, key interview topics were experiences of commissioning YOD services, perceived facilitators or barriers, and how future guidance should be structured for ease of use. For service providers, key topics explored experiences of delivering YOD services; what was achievable or challenging; how the service was funded; how it linked with broader provision for YOD in the area; and how guidance should be structured. RESULTS: Recorded interviews lasted 30–40 minutes. Seven key facilitators to the development and sustaining of YOD services were identified: having knowledgeable, committed local champions; involvement of people living with YOD and family supporters; initial delivery within existing resources; partnership working within and between sectors; having a reflective, supportive organizational culture; gathering evidence of impact; and having wider support and guidance. CONCLUSIONS: Improvements in provision for those with YOD and their families need to be built on understanding of service-level and interpersonal influences as well as on understanding of YOD itself. Our findings highlight a set of facilitators which need to be in place to establish and sustain high-quality YOD services that fit the local context

Systematic variation of the stellar Initial Mass Function with velocity dispersion in early-type galaxies

An essential component of galaxy formation theory is the stellar initial mass function (IMF), that describes the parent distribution of stellar mass in star forming regions. We present observational evidence in a sample of early-type galaxies (ETGs) of a tight correlation between central velocity dispersion and the strength of several absorption features sensitive to the presence of low-mass stars. Our sample comprises ~40,000 ETGs from the SPIDER survey (z<0.1). The data, extracted from the Sloan Digital Sky Survey, are combined, rejecting both noisy data, and spectra with contamination from telluric lines, resulting in a set of 18 stacked spectra at high signal-to-noise ratio (S/N> 400 per A). A combined analysis of IMF-sensitive line strengths and spectral fitting is performed with the latest state-of the art population synthesis models (an extended version of the MILES models). A significant trend is found between IMF slope and velocity dispersion, towards an excess of low-mass stars in the most massive galaxies. Although we emphasize that accurate values of the IMF slope will require a detailed analysis of chemical composition (such as [a/Fe] or even individual element abundance ratios), the observed trends suggest that low-mass ETGs are better fit by a Kroupa-like IMF, whereas massive galaxies require bottom-heavy IMFs, exceeding the Salpeter slope at velocity dispersions above 200km/s.Comment: 5 pages, 4 figures, accepted for publication in MNRAS Letter

How non-linear scaling relations unify dwarf and giant elliptical galaxies

Dwarf elliptical galaxies are frequently excluded from bright galaxy samples because they do not follow the same linear relations in diagrams involving effective half light radii R_e or mean effective surface brightnesses _e. However, using two linear relations which unite dwarf and bright elliptical galaxies we explain how these lead to curved relations when one introduces either the half light radius or the associated surface brightness. In particular, the curved _e - R_e relation is derived here. This and other previously misunderstood curved relations, once heralded as evidence for a discontinuity between faint and bright elliptical galaxies at M_B ~ -18 mag, actually support the unification of such galaxies as a single population whose structure (i.e. stellar concentration) varies continuously with stellar luminosity and mass.Comment: 4 pages including 2 figures, to appear in "A Universe of dwarf galaxies", Conf. Proc. (Lyon, June 14-18, 2010

Young-onset dementia: scoping review of key pointers to diagnostic accuracy

Background Routine psychiatric assessments tailored to older patients are often insufficient to identify the complexity of presentation in younger patients with dementia. Significant overlap between psychiatric disorders and neurodegenerative disease means that high rates of prior incorrect psychiatric diagnosis are common. Long delays to diagnosis, misdiagnosis and lack of knowledge from professionals are key concerns. No specific practice guidelines exist for diagnosis of young onset dementia (YOD). Aim The review evaluates the current evidence about best practice in diagnosis to guide thorough assessment of the complex presentations of YOD with a view to upskilling professionals in the field. Method A comprehensive search of the literature adopting a scoping review methodology was conducted regarding essential elements of diagnosis in YOD, over and above those in current diagnostic criteria for disease subtypes. This methodology was chosen because research in this area is sparse and not amenable to a traditional systematic review. Results The quality of evidence identified is variable with the majority provided from expert opinion and evidence is lacking on some topics. Evidence appears weighted towards diagnosis in fronto-temporal dementia (FTD) and its subtypes and young onset Alzheimer’s disease (AD). Conclusion The literature demonstrates that a clinically rigorous and systematic approach is necessary in order to avoid mis- or under-diagnosis for younger people. The advent of new disease modifying treatments necessitates clinicians in the field to improve knowledge of new imaging techniques and genetics, with the goal of improving training and practice, and highlights the need for quality indicators and alignment of diagnostic procedures across clinical settings