407 research outputs found

    Variations in tectonic style and setting in British coalfields

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    British Carboniferous coalfield datasets are used for mapping, analysis, and modelling of depositional and structural patterns, through a significant stratigraphical range and across a variety of tectonic settings. Westphalian depositional patterns are re-interpreted using channel axis orientations. Major flows were northeasterly into northeast Britain, westerly into the Pennine Basin, and southwesterly through South Wales. Most systems prograded into freshwater lakes. Tectonic depocentres had little effect on channel pathways, but significant effects on net depositional thicknesses, and sandstone and coal connectivity patterns. Varying depositional controls are evaluated, and a complex model is proposed, integrating these; simple sequence stratigraphical interpretations are inappropriate. Many sulphur variations in the coals reflect the channel inflows rather than marine invasions, which were only occasionally important, and were moderated by many local effects. Structural and sedimentological criteria are proposed for the identification of syn-depositional faulting. Except in Scotland, few syn-depositional movements on specific faults are identifiable from the sedimentary record; some inherited structures continued to grow, as sub-basin bounding faults. These, and large post-depositional structures, generated mosaics of crustal compartments within which fault patterns and jointing orientations demonstrate varied block responses to tectonic events. Coal jointing orientations are considered to record Variscan near, far, and distant field stress, progressively north from South Wales, across central/northem England, and into Scotland. Recent data on Carboniferous igneous activity are described and interpreted in the Scottish Midland Valley. The Westphalian igneous provinces of the southern Pennine Basin and Oxfordshire are discussed and recommended for further research. Two case studies illustrate ways in which detailed coalfield data may be used for regional tectonic analysis, namely the evolution of the Kincardine Basin and Ochil Fault in Scotland, and the identification of a specific Variscan thrusting style in Kent

    Slow escaping points of quasiregular mappings

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    This article concerns the iteration of quasiregular mappings on Rd and entire functions on C. It is shown that there are always points at which the iterates of a quasiregular map tend to infinity at a controlled rate. Moreover, an asymptotic rate of escape result is proved that is new even for transcendental entire functions. Let f:Rd→Rd be quasiregular of transcendental type. Using novel methods of proof, we generalise results of Rippon and Stallard in complex dynamics to show that the Julia set of f contains points at which the iterates fn tend to infinity arbitrarily slowly. We also prove that, for any large R, there is a point x with modulus approximately R such that the growth of |fn(x)| is asymptotic to the iterated maximum modulus Mn(R,f)

    The iterated minimum modulus and conjectures of Baker and Eremenko

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    In transcendental dynamics significant progress has been made by studying points whose iterates escape to infinity at least as fast as iterates of the maximum modulus. Here we take the novel approach of studying points whose iterates escape at least as fast as iterates of the minimum modulus, and obtain new results related to Eremenko's conjecture and Baker's conjecture, and the rate of escape in Baker domains. To do this we prove a result of wider interest concerning the existence of points that escape to infinity under the iteration of a positive continuous function

    The lateral and ventromedial prefrontal cortex work as a dynamic integrated system:evidence from FMRI connectivity analysis

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    Recent functional magnetic resonance imaging (fMRI) investigations of the interaction between cognition and reward processing have found that the lateral prefrontal cortex (PFC) areas are preferentially activated to both increasing cognitive demand and reward level. Conversely, ventromedial PFC (VMPFC) areas show decreased activation to the same conditions, indicating a possible reciprocal relationship between cognitive and emotional processing regions. We report an fMRI study of a rewarded working memory task, in which we further explore how the relationship between reward and cognitive processing is mediated. We not only assess the integrity of reciprocal neural connections between the lateral PFC and VMPFC brain regions in different experimental contexts but also test whether additional cortical and subcortical regions influence this relationship. Psychophysiological interaction analyses were used as a measure of functional connectivity in order to characterize the influence of both cognitive and motivational variables on connectivity between the lateral PFC and the VMPFC. Psychophysiological interactions revealed negative functional connectivity between the lateral PFC and the VMPFC in the context of high memory load, and high memory load in tandem with a highly motivating context, but not in the context of reward alone. Physiophysiological interactions further indicated that the dorsal anterior cingulate and the caudate nucleus modulate this pathway. These findings provide evidence for a dynamic interplay between lateral PFC and VMPFC regions and are consistent with an emotional gating role for the VMPFC during cognitively demanding tasks. Our findings also support neuropsychological theories of mood disorders, which have long emphasized a dysfunctional relationship between emotion/motivational and cognitive processes in depression

    Supporting induction: relationships count

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    This article examines the structural changes to the induction of teachers in Scotland using the perceptions of a group of final year student teachers. This group would be the first probationer teachers to experience revised arrangements for new teacher induction in 37 years. Their preferences and concerns are highlighted, as the new procedures roll out in schools nationwide, in an attempt to stress the importance of relationships to the success of the induction scheme. The argument put forward in this article is based on the notion that personal intelligence is central to effective relationships and therefore crucially important in the context of this mentoring relationship. The views of our sample provide evidence to suggest that the quality of interactions between the mentor and the probationer teacher are paramount in providing a good induction experience. These views are substantiated by experiences in England and in induction literature elsewhere. A synthesis of this evidence is used to make recommendations for those involved in supporting induction in schools, local authorities or teacher education institutions

    What makes a good induction supporter?

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    The Teacher Induction Scheme, introduced in 2002, marked the first major change to new teacher induction in Scotland in 37 years. This paper gives an outline of these changes set against developments in mentoring theory in the wider context. It argues that the personal qualities of the induction supporter are crucial to developing an effective mentoring relationship. The views of student teachers are used to describe preferred characteristics of effective mentors and effective induction provision. A person specification is created by the comments of the "Class of 2002" — the first probationer teachers to have taken part in the Scheme

    On questions of Fatou and Eremenko

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    Let ff be a transcendental entire function and let I(f)I(f) be the set of points whose iterates under ff tend to infinity. We show that I(f)I(f) has at least one unbounded component. In the case that ff has a Baker wandering domain, we show that I(f)I(f) is a connected unbounded set

    How organizational cognitive neuroscience can deepen understanding of managerial decision-making:a review of the recent literature and future directions

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    There is growing interest in exploring the potential links between human biology and management and organization studies, which is bringing greater attention to bear on the place of mental processes in explaining human behaviour and effectiveness. The authors define this new field as organizational cognitive neuroscience (OCN), which is in the exploratory phase of its emergence and diffusion. It is clear that there are methodological debates and issues associated with OCN research, and the aim of this paper is to illuminate these concerns, and provide a roadmap for rigorous and relevant future work in the area. To this end, the current reach of OCN is investigated by the systematic review methodology, revealing three clusters of activity, covering the fields of economics, marketing and organizational behaviour. Among these clusters, organizational behaviour seems to be an outlier, owing to its far greater variety of empirical work, which the authors argue is largely a result of the plurality of research methods that have taken root within this field. Nevertheless, all three clusters contribute to a greater understanding of the biological mechanisms that mediate choice and decision-making. The paper concludes that OCN research has already provided important insights regarding the boundaries surrounding human freedom to act in various domains and, in turn, self-determination to influence the workplace. However, there is much to be done, and emerging research of significant interest is highlighted

    A twenty-year survey of dermatophytoses in Braga, Portugal

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    Modifications in social habits together with the increase of emigration have contributed not only to increased dermatophytoses but also to an altered etiology. During the last few years, Braga has suffered a radical change from a rural to a cosmopolitan life-style

    Generation of lung epithelial-like tissue from human embryonic stem cells

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    <p>Abstract</p> <p>Background</p> <p>Human embryonic stem cells (hESC) have the capacity to differentiate <it>in vivo </it>and <it>in vitro </it>into cells from all three germ lineages. The aim of the present study was to investigate the effect of specific culture conditions on the differentiation of hESC into lung epithelial cells.</p> <p>Methods</p> <p>Undifferentiated hESC, grown on a porous membrane in hESC medium for four days, were switched to a differentiation medium for four days; this was followed by culture in air-liquid interface conditions during another 20 days. Expression of several lung markers was measured by immunohistochemistry and by quantitative real-time RT-PCR at four different time points throughout the differentiation and compared to appropriate controls.</p> <p>Results</p> <p>Expression of <it>CC16 </it>and <it>NKX2.1 </it>showed a 1,000- and 10,000- fold increase at day 10 of differentiation. Other lung markers such as <it>SP-C </it>and <it>Aquaporin 5 </it>had the highest expression after twenty days of culture, as well as two markers for ciliated cells, <it>FOXJ1 </it>and <it>β-tubulin IV</it>. The results from qRT-PCR were confirmed by immunohistochemistry on paraffin-embedded samples. Antibodies against CC16, SP-A and SP-C were chosen as specific markers for Clara Cells and alveolar type II cells. The functionality was tested by measuring the secretion of CC16 in the medium using an enzyme immunoassay.</p> <p>Conclusion</p> <p>These results suggest that by using our novel culture protocol hESC can be differentiated into the major cell types of lung epithelial tissue.</p
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