On the relevance of numerical simulations to booming sand

We have performed a simulation study of 3D cohesionless granular flows down an inclined chute. We find that the oscillations observed in [L.E. Silbert, Phys. Rev. Lett., 94, 098002 (2005)] near the angle of repose are harmonic vibrations of the lowest normal mode. Their frequencies depend on the contact stiffness as well as on the depth of the flow. Could these oscillations account for the phenomena of "booming sand"? We estimate an effective contact stiffness from the Hertz law, but this leads to frequencies several times higher than observed. However, the Hertz law also predicts interpenetrations of a few nanometers, indicating that the oscillations frequencies are governed by the surface stiffness, which can be much lower than the bulk one. This is in agreement with previous studies ascribing the ability to sing to the presence of a soft coating on the grain surface.Comment: accepted for publication in Physical Review E http://pre.aps.org; Physical Review E (2012) to be publishe

Stigma and treatment of eating disorders in Ireland: healthcare professionals' knowledge and attitudes

Objectives: This study examines aspects of health professionals’ knowledge and attitudes about eating disorders (EDs) , which might impede the effective detection or treatment of EDs in Ireland. Methods: 1,916 health professionals were invited to participate in a web-based survey. Participants were randomly allocated to view one of five vignettes depicting a young person with symptoms consistent with Anorexia Nervosa, Bulimia Nervosa, Binge Eating Disorder, Depression or Type 1 Diabetes. Study-specific questions examined participants’ responses to the vignettes and ED knowledge and experience

Eating disorder literacy and stigmatising attitudes towards anorexia, bulimia and binge eating disorder among adolescents

Little research has investigated adolescents’ understanding of eating disorders (EDs) or attitudes towards people affected by EDs. This impedes the development of targeted health promotion interventions. In the current study, 290 adolescents viewed a vignette depicting a target with either Anorexia Nervosa, Bulimia Nervosa, Binge Eating Disorder, Depression or Type 1 Diabetes. Subsequent questionnaires assessed understanding of and attitudes towards the disorder described . Adolescents recognised the symptoms of depression significantly more frequently than any ED. Relative to depression and Type 1 diabetes, participants held targets with EDs more personally responsible for their illness and ascribed them more negative personality characteristics. The data revealed a particularly unfavourable view of Binge Eating Disorder, which was conceptualised as a failure of self-discipline rather than a medical condition. The results confirm previous findings that EDs are more stigmatised than other mental or physical health conditions and extend the findings to an adolescent cohort

Eating disorder services for young people in Ireland: perspectives of service providers, service users and the general adolescent population

Objectives: This paper illuminates how national eating disorder (ED) policy translates into day-to-day practice by exploring how ED services are experienced by those who deliver and use them. Methods: A mixed-methods approach was used, which combined qualitative and quantitative techniques. The paper collates data from three studies: (i) an interview study exploring the lived experiences of young people with EDs (n =8), their parents (n =5) and their healthcare professionals (n =3); (ii) a national survey of health professionals’ perspectives on existing ED services (n =171); (iii) a nationwide survey of secondary-school students’ eating concerns and patterns of help - seeking (n=290). Results: The qualitative interviews with young people and their parents revealed feelings of isolation and helplessness. Young people expressed interest in patient support groups, while parents desired greater support for the family unit. Parents were highly critical of available services, particularly in relation to access. These criticisms were echoed in the survey of healthcare professionals, who reported many barriers to delivering effective care. Clinicians were almost unanimous in calling for care pathways to be clarified via a standardised treatment protocol. The survey of adolescents indicated widespread reluctance to seek help regarding eating concerns: over one-third expressed concern about their own eating habits, but half of these had not divulged their concerns to anyone. Participants’ preferred pathways of help-seeking revolved around family and friends, and adolescents were unsure about routes of access to professional support. 3 Conclusions: The research demonstrates that many aspects of national ED policy have not been implemented in practice. The paper highlights specific gaps and suggests ways they can be redressed

Hot Atmospheres, Cold Gas, AGN Feedback and the Evolution of Early Type Galaxies: a Topical Perspective

Most galaxies comparable to or larger than the mass of the Milky Way host hot, X-ray emitting atmospheres, and many such galaxies are radio sources. Hot atmospheres and radio jets and lobes are the ingredients of radio-mechanical active galactic nucleus (AGN) feedback. While a consensus has emerged that such feedback suppresses cooling of hot cluster atmospheres, less attention has been paid to massive galaxies where similar mechanisms are at play. Observation indicates that the atmospheres of elliptical and S0 galaxies were accreted externally during the process of galaxy assembly and augmented significantly by stellar mass loss. Their atmospheres have entropy and cooling time profiles that are remarkably similar to those of central cluster galaxies. About half display filamentary or disky nebulae of cool and cold gas, much of which has likely cooled from the hot atmospheres. We review the observational and theoretical perspectives on thermal instabilities in galactic atmospheres and the evidence that AGN heating is able to roughly balance the atmospheric cooling. Such heating and cooling may be regulating star formation in all massive spheroids at late times.Comment: Final versio

Two new Ramsey numbers

A graph with many vertices cannot be homogeneous, i.e., for any pair of integers (i,j) all large graphs must contain either a complete subgraph on i vertices or an independent set of size j. The Ramsey number for (i,j) is the smallest integer R such that all graphs with at least R vertices have this property. For example, the (3,3) Ramsey number is 6; if a graph has 6 or more vertices, then is must contain a triangle or an independent set of size 3. The (4,4) Ramsey number is 18, found in 1954 [GG] . The (5,5) Ramsey number is still unknown; it is between 43 and 52. This thesis deals with subgraphs slightly different from the classical types. The subgraphs here are complete graphs with one edge missing and induced subgraphs with exactly one edge. The (4,6) and (4,7) Ramsey numbers for these types of subgraphs is computed. The method used is an exhaustive search, with many shortcuts employed to reduce computation time

Manipulating cellular growth responses to patterning, apoptotic, and environmental cues

In this work, various methods of controlling cell growth are examined. Cell-cell interaction, apoptotic cues, three dimensional scaffolds, and non-adherent environments are evaluated for their ability to affect the differentiation, morphology, and growth rate of different cell types. Previous work has shown that cell growth and cell morphology can be influenced by patterns of polymers coated on surfaces in two dimensions, designated here as the x and y dimensions of a standard Cartesian coordinate system. Tissue engineering and regenerative medicine studies have shown limited success in modifying growth in the third, z dimension. This work considers not only the x, y, and z dimensions, but also the fourth dimension, time. The time dimension is explored via apoptosis. The x and y dimensions are inspected through surface patterning, and the three physical dimensions are scrutinized together by means of scaffolding-cultured cells and cytophobic surfaces for non-adherent aspects of cell patterning. The project goals accomplished here are: (1) to develop a simple model of apoptosis that can be used to determine visually the temporal progression of apoptosis and to determine whether staurosporine-induced apoptosis can be delayed by pre-treatment of cells with glutamate, (2) to determine the viability of a cellulose/gelatin biologically-derived 3D cellular scaffolding construct as a platform for tissue engineering, (3) to develop a novel cell-adherence blocking strategy that will improve the localization of cell adherence to patterns deposited by the NanoEnabler® system. Measures of apoptotic activity based on digital images showing changes in cell area, cell shape, nuclear area and nuclear shape were used to develop the Cell Area Factor and Nuclear Area Factor model. Biochemical assays for mitochondrial activity and for caspase 3 (casp3) activity showed a delay in staurosporine induced apoptosis. Digital images of the scaffold materials demonstrated the scaffold\u27s ability to encourage cell invasion, growth and differentiation. The image observations were supported by MTT assays showing increased metabolic activity of the cell indicating proliferative culture. The adherence blocking strategy discussed resulted in 3D growth of cancerous brain tumor cells tracked via digital imaging and tumor area analysis. Calcein vital dye staining supported the evidence for a growing tumor colony. The three approaches for cell growth modification, apoptotic stimuli, scaffolding directional cues, and negative adhesive cues (cytophobic surfaces), are considered as building blocks that can be combined in a broader tissue engineering strategy to control the adhesion, morphology, and differentiation of cells. The apoptotic modulator chronicled in this work can be used to modify biological pathways in vitro and provide a more biomimetic environment that can be used to engineer tissues and to formulate and test new experimental hypotheses. The success of the biologically derived cellulose/gelatin material indicates that further work is warranted to develop it as a scaffold to support and cultivate 3D engineered, spatially defined tissues. The cytophobic surface has lead not only to a new blocking strategy, but also to the unexpected result of leading to a novel 3D model of cancer progression in vitro that closely resembles the in vivo situation

"Everyone here wants everyone else to get better": the role of social identity in eating disorder recovery

Retention of a positively valued illness identity contributes to poor outcomes for individuals with eating disorders. Consequently, dis-identification from the illness identity and the adoption of a recovery identity is vital for successful recovery. While social identity processes have been shown to influence eating disorder maintenance, their role in recovery is rarely considered. This study explores how a sense of shared identity helps individuals with eating disorders manage their condition and promotes recovery. Transcripts from 18 online support sessions involving 75 participants were thematically analysed. Our findings suggest that the illness identity initially operates as a social identity that forms the basis for connections with similar others. For those wishing to recover, identity-based support is then perceived to be more effective than that found outside the group. Online interactions also facilitate construction of a new shared recovery identity which promotes a shift from the illness identity as a primary source of definition and endorses group norms of illness disclosure and treatment engagement. While in the clinical literature, eating disorder identity is seen as problematic and interventions are targeted at challenging an individual’s self-concept, we suggest that interventions could instead harness identity resources to support a transition to a recovery identity

Adolescents' and parents' views of Child and Adolescent Mental Health Services (CAMHS) in Ireland

Aim: To explore adolescents’ and parents’ experiences of CAMHS in relation to accessibility, approachability, and appropriateness. Methods: Using a descriptive qualitative design, a combination of focus group and single interviews were conducted with adolescents (n=15) and parents (n=32) from three mental health clinics. Data were transcribed verbatim and analysed using thematic analysis. Results: Accessing mental health services was a challenging experience due to knowledge deficit, lack of information and limited availability of specialist services. Participants desired more information, involvement in decision-making, single and shared consultations, flexible scheduling of appointments, continuity with clinicians, school support and parent support groups. Participants seem to be generally satisfied, however adolescents felt less involved in decision making than they would have liked. Frequent staff changes was problematic as it disrupted continuity of care and hindered the formation of a trusting relationship. Implications for practice: Parents and adolescents expressed similar views of the positive and negative aspects of mental health services. Their need for more information-sharing and involvement in decision-making underline the importance of collaborative practice. Clinician continuity contributed to trusting therapeutic relationships and was valued. These are key principles that with attention, could lead to quality service provision for adolescents and families