2,689 research outputs found

    Damping of vertical coronal loop kink oscillations through wave tunneling

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    The decay rate of vertical kink waves in a curved flux tube is modeled numerically. The full MHD equations are solved for a curved equilibrium flux tube in an arcade geometry and the decay of ψ, the integral over the flux tube of the modulus of the velocity perpendicular to the local magnetic field, is measured. These simulations are 2D and are thus restricted to kink oscillations in the loop plane. The decay rate is found to increase with increasing wavelength, increasing ÎČ and decreasing density contrast ratio. The wave tunneling eïŹ€ect is shown to be a possible mechanism for the high decay rate of the recent observed kink oscillation reported by Wang & Solanki (2004)

    Gender, marital status and intergenerational relations in a changing world

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    The worldwide trend towards ageing of societies is well documented with extensive discussions of support and care needs for frail older people. There is less discussion of the implications of gender differences in later life for access to support in the event of frailty or disability. Although, marital status is fundamental to well-being in later life (Arber and Ginn, 1991, 1995; Gaymu et al., 2008), there has been less appreciation of the scale of gender difference in marital status in later life, variations between societies, and their implications. It is important to consider the interaction between gender and marital status and the ways this may change over time (Arber, 2004a; Arber, 2004b; Manning and Brown, 2011). The focus of this chapter is to examine the intersection of gender and marital status in later life across societies, how this links to inter-generational relations, and how global changes make it increasingly important to consider the implications of the gender and marital status interaction when studying access to caregivers and social support in later life

    Leakage of waves from coronal loops by wave tunneling

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    To better understand the decay of vertically polarised fast kink modes of coronal loops by the mechanism of wave tunneling, simulations are performed of fast kink modes in straight flux slabs which have AlfvĂ©n speed profiles which include a tunneling region. The decay rates are found to be determined by the mode number of the trapped mode and the thickness of the tunneling region. Two analytical models are suggested to explain the observed decay. The first is a extension of the work of Roberts (1981, Sol. Phys., 69, 39) to include a finite thickness tunneling region, and the second is a simpler model which yields an analytical solution for the relationship between decay rate, period and the thickness of the tunneling region. The decay rates for these straight slabs are found to be slower than in observations and those found in a previous paper on the subject by Brady & Arber (2005, A&A, 438, 733) using curved flux slabs. It is found that the diïŹ€erence between the straight slabs used here and the curved slabs used in Brady & Arber (2005, A&A, 438, 733) can be represented as a geometric correction to the decay rate

    Caring for a loved one with a malignant fungating wound

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    Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Purpose: Caring for a loved one with a malignant fungating wound is very challenging and causes extreme physical and psychological distress. The aim of this study was to explore the experiences of carers who care for a loved one with a fungating breast wound. Method: To explore the lived experiences of carers, a methodological framework using Heideggerian hermeneutic phenomenology and semi-structured interviews was used. Seven carers were interviewed from January until November 2009. Results: Having to deal with a situation of a loved one with a visible cancer was hard for all the carers. The visibility of the cancer was one of the most shocking aspects to deal with from the perspective of the patient and the carer. The presence of the visible wound and a cancer at an advanced stage contributed to a change in the relationship and extreme suffering for both the patient and the carer. Despite many problems such as wound odour and copious discharge from the wound, which was difficult to control, carers did their best to help their loved one with the wound. Gradually, the wound became the centre of the patient and carer’s life, and a great deal of time was spent trying to control the wound symptoms. All carers managed the wound on their own without help and advice from health care practitioners. For all of them, it was a major burden and they felt isolated. Conclusion: This study contributes to an understanding that the care of women and their carers needs strategies that are integrated in palliative wound care that takes a holistic and empathic approach that responds to patients’ and carers’ psychosocial and emotional needs and a practical need for information to help carers assist in managing the wound-related symptoms

    Stem cell models of Alzheimer's disease: progress and challenges.

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    A major challenge to our understanding of the molecular mechanisms of Alzheimer's disease (AD) has been the lack of physiologically relevant in vitro models which capture the precise patient genome, in the cell type of interest, with physiological expression levels of the gene(s) of interest. Induced pluripotent stem cell (iPSC) technology, together with advances in 2D and 3D neuronal differentiation, offers a unique opportunity to overcome this challenge and generate a limitless supply of human neurons for in vitro studies. iPSC-neuron models have been widely employed to model AD and we discuss in this review the progress that has been made to date using patient-derived neurons to recapitulate key aspects of AD pathology and how these models have contributed to a deeper understanding of AD molecular mechanisms, as well as addressing the key challenges posed by using this technology and what progress is being made to overcome these. Finally, we highlight future directions for the use of iPSC-neurons in AD research and highlight the potential value of this technology to neurodegenerative research in the coming years

    Simulations of Alfvén and Kink wave driving of the solar chromosphere : efficient heating and spicule launching

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    Two of the central problems in our understanding of the solar chromosphere are how the upper chromosphere is heated and what drives spicules. Estimates of the required chromospheric heating, based on radiative and conductive losses, suggest a rate of ~0.1 erg cm−3 s−1 in the lower chromosphere and drops to ~10−3 erg cm−3 s−1 in the upper chromosphere. The chromosphere is also permeated by spicules, higher density plasma from the lower atmosphere propelled upwards at speeds of ~10–20 km s−1, for so-called Type I spicules, which reach heights of ~3000–5000 km above the photosphere. A clearer understanding of chromospheric dynamics, its heating, and the formation of spicules is thus of central importance to solar atmospheric science. For over 30 years it has been proposed that photospheric driving of MHD waves may be responsible for both heating and spicule formation. This paper presents results from a high-resolution MHD treatment of photospheric driven AlfvĂ©n and kink waves propagating upwards into an expanding flux tube embedded in a model chromospheric atmosphere. We show that the ponderomotive coupling from AlfvĂ©n and kink waves into slow modes generates shocks, which both heat the upper chromosphere and drive spicules. These simulations show that wave driving of the solar chromosphere can give a local heating rate that matches observations and drive spicules consistent with Type I observations all within a single coherent model

    Consommation des jeunes et jeunes adultes en fin de semaine : Evolution entre 2011, 2013 et 2015

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    Parmi les 691 jeunes de 15 Ă  29 ans qui ont participĂ© au module jeune en 2015, 629 sont sortis au cours des 30 jours prĂ©cĂ©dant la passation de l’enquĂȘte. Les rĂ©ponses donnĂ©es par ces derniers permettent de complĂ©ter les rĂ©sultats dĂ©jĂ  obtenus prĂ©cĂ©demment concernant les consommations des jeunes lors de leur derniĂšre sortie de fin de semaine. De maniĂšre gĂ©nĂ©rale, il n’existe pas de tendance nette chez les jeunes vers une hausse ou une diminution de la consommation de substances entre 2011 et 2015. L’alcool reste la substance la plus consommĂ©e par les jeune

    Premier bilan du projet de renforcement du dispositif addictologique de l’Ouest vaudois : Ă©valuation de la pĂ©riode 2015-2016

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    Objectifs et mĂ©thode : A la demande du Service de la santĂ© publique (SSP), un premier Ă©tat des lieux du projet a Ă©tĂ© menĂ© en juin 2016, soit dix-huit mois aprĂšs son dĂ©marrage, afin d’explorer les activitĂ©s mises en oeuvre, les difficultĂ©s rencontrĂ©es et les lacunes constatĂ©es lors la mise en place de la collaboration et afin de proposer quelques pistes d’ajustement du dispositif. Une Ă©tude de cas descriptive a Ă©tĂ© rĂ©alisĂ©e au moyen d’entretiens semi-dirigĂ©s avec le responsable du PĂŽle addictologique et le directeur d’EdS et d’une analyse de documents relatifs au projet. L’analyse des donnĂ©es a portĂ© d’une part sur l’implantation du projet en termes d’adhĂ©sion au protocole initial, d’exposition et de qualitĂ© et d’autre part sur les dimensions normative (vision globale du projet), fonctionnelle (outils et procĂ©dures rĂ©gissant les rĂŽles et les responsabilitĂ©s) et clinique (outils et procĂ©dures dĂ©finissant la prise en charge et l’accompagnement des patients) de la collaboration entre EdS et le PĂŽle addictologique

    Perceptions of childhood immunization in a minority community: Qualitative study

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    This is the author's accepted manuscript. The final published article is available from the link below. Published article copyright @ The Royal Society of Medicine.Objective - To assess reasons for low uptake of immunization amongst orthodox Jewish families. Design - Qualitative interviews with 25 orthodox Jewish mothers and 10 local health care workers. Setting - The orthodox Jewish community in North East London. Main outcome measures - Identification of views on immunization in the orthodox Jewish community. Results - In a community assumed to be relatively insulated from direct media influence, word of mouth is nevertheless a potent source of rumours about vaccination dangers. The origins of these may lie in media scares that contribute to anxieties about MMR. At the same time, close community cohesion leads to a sense of relative safety in relation to tuberculosis, with consequent low rates of BCG uptake. Thus low uptake of different immunizations arises from enhanced feelings of both safety and danger. Low uptake was not found to be due to the practical difficulties associated with large families, or to perceived insensitive cultural practices of health care providers. Conclusions - The views and practices of members of this community are not homogeneous and may change over time. It is important that assumptions concerning the role of religious beliefs do not act as an obstacle for providing clear messages concerning immunization, and community norms may be challenged by explicitly using its social networks to communicate more positive messages about immunization. The study provides a useful example of how social networks may reinforce or challenge misinformation about health and risk and the complex nature of decision making about children's health.City and Hackney Teaching Primary Care Trus

    Managing sleep and wakefulness in a 24 hour world

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    This article contributes to literature on the sociology of sleep by exploring the sleeping practices and subjective sleep experiences of two social groups: shift workers and students. It draws on data, collected in the UK from 25 semi-structured interviews, to discuss the complex ways in which working patterns and social activities impact upon experiences and expectations of sleep in our wired awake world. The data show that, typically, sleep is valued and considered to be important for health, general wellbeing, appearance and physical and cognitive functioning. However, sleep time is often cut back on in favour of work demands and social activities. While shift workers described their efforts to fit in an adequate amount of sleep per 24-hour period, for students, the adoption of a flexible sleep routine was thought to be favourable for maintaining a work–social life balance. Collectively, respondents reported using a wide range of strategies, techniques, technologies and practices to encourage, overcome or delay sleep(iness) and boost, promote or enhance wakefulness/alertness at socially desirable times. The analysis demonstrates how social context impacts not only on how we come to think about sleep and understand it, but also how we manage or self-regulate our sleeping patterns
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