856 research outputs found

    Persistent inequality when learning requires a minimal standard of living

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    This paper studies the persistence of wealth and utility inequality in a dynamicmodel of skill acquisition with complete credit markets and rational, perfectly altruistic,dynastic utility-maximization, when efficient learning requires a minimal standardof living. The main result is that, if the minimal standard of living is not triviallysmall, at any stationary equilibrium without intergenerational mobility there are?poor?, unskilled and ?rich?, skilled dynasties. Members of rich dynasties inherit morefrom their parents than members of poor dynasties. The former in general acquireskill, while the latter remain unskilled, and - most importantly - members of rich familiesalso enjoy strictly higher utility than members of poor dynasties. This paper studies the persistence of wealth and utility inequality in a dynamicmodel of skill acquisition with complete credit markets and rational, perfectly altruistic,dynastic utility-maximization, when efficient learning requires a minimal standardof living. The main result is that, if the minimal standard of living is not triviallysmall, at any stationary equilibrium without intergenerational mobility there are?poor?, unskilled and ?rich?, skilled dynasties. Members of rich dynasties inherit morefrom their parents than members of poor dynasties. The former in general acquireskill, while the latter remain unskilled, and - most importantly - members of rich familiesalso enjoy strictly higher utility than members of poor dynasties

    Correlation of memory T cell responses against TRAP with protection from clinical malaria, and CD4+ CD25high T cells with susceptibility in Kenyans

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    Background - Immunity to malaria develops naturally in endemic regions, but the protective immune mechanisms are poorly understood. Many vaccination strategies aim to induce T cells against diverse pre-erythrocytic antigens, but correlates of protection in the field have been limited. The objective of this study was to investigate cell-mediated immune correlates of protection in natural malaria. Memory T cells reactive against thrombospondin-related adhesive protein (TRAP) and circumsporozoite (CS) protein, major vaccine candidate antigens, were measured, as were frequencies of CD4+ CD25high T cells, which may suppress immunity, and CD56+ NK cells and γδ T cells, which may be effectors or may modulate immunity. Methodology and Principal Findings - 112 healthy volunteers living in rural Kenya were entered in the study. Memory T cells reactive against TRAP and CS were measured using a cultured IFNγ ELISPOT approach, whilst CD4+ CD25high T cells, CD56+ NK cells, and γδ T cells were measured by flow cytometry. We found that T cell responses against TRAP were established early in life (<5 years) in contrast to CS, and cultured ELISPOT memory T cell responses did not correlate with ex-vivo IFNγ ELISPOT effector responses. Data was examined for associations with risk of clinical malaria for a period of 300 days. Multivariate logistic analysis incorporating age and CS response showed that cultured memory T cell responses against TRAP were associated with a significantly reduced incidence of malaria (p = 0.028). This was not seen for CS responses. Higher numbers of CD4+ CD25high T cells, potentially regulatory T cells, were associated with a significantly increased risk of clinical malaria (p = 0.039). Conclusions - These data demonstrate a role for central memory T cells in natural malarial immunity and support current vaccination strategies aimed at inducing durable protective T cell responses against the TRAP antigen. They also suggest that CD4+ CD25high T cells may negatively affect naturally acquired malarial immunity

    Northern English Dialects: A perceptual approach

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    Perceptual dialectology has the capacity to deliver a great many benefits to the study of language varieties. It also allows examination of the underlying factors in dialect use such as the ‘beliefs, attitudes and strategies’ (Preston, 1999: xxiii) which make up language users’ reactions to language varieties. In this way it has the potential to ask questions of identity and explore the reasons for dialect loyalty as well as complementing other research in the field of language variation and change. Using a perceptual framework, this research investigates the relationship between the north and south of England and gains access to some of the key concepts which affect informants’ view of this important social, cultural and historical relationship. Perceptions of salient dialect areas are also assessed using informants from three locations in the north of England via the completion of a draw-a-map task (Preston, 1999: xxxiv). Many of the factors which impact on the perception of dialect areas are discussed, with phenomena of proximity and cultural salience demonstrating an important role. An analysis of informants’ reactions to voice samples from across England is also undertaken using methods adapted from the fields of linguistics (Embleton & Wheeler, 1997, Giles & Powesland, 1975, Niedzielski & Preston, 2003) as well perceptual geography (Pocock, 1972). The link between map-based perception and reaction to voice samples is examined, with interesting conclusions. Four key research questions are addressed: 1. Do respondents have a linguistic ‘cognitive map’ of a north of England, and do respondents recognise there to be internal boundaries within ‘their’ north of England? 2. Does home-town location of informants affect the perception of dialect area? 3. What are informants’ perceptions of the language varieties in the north of England? 4. Is there a relationship between perception and ‘reality’ (production), and can respondents recognise the varieties they have identified? These questions will be addressed using the methods described above and the results accounted for through comparison with a wide range of previous studies in the fields of dialectology (Trudgill, 1999, Upton, Sanderson & Widdowson, 1987, Wells, 1982), social and cultural history (Wales, 2006), perceptual dialectology (Long & Preston, 2002), sociolinguistics (Giles & Powesland, 1975) and perceptual geography (Gould & White, 1986)

    Motivators of educational success: Perceptions of grade 12 Aboriginal students

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    Source type: Print(0

    Historical Research on Music Education and Music Therapy in the United State: Doctoral Dissertations of the Twentieth Century

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    abstract: This article presents an analysis of all dissertations directly related to music education and music therapy produced at U.S. institutions throughout the twentieth century--with concentration on the period since a prior study (last decade)
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