61 research outputs found
Calcium as a second messenger in neuronal growth cones
No full textCalcium is thought to be involved in the regulation of motility and growth in the neuronal growth cone. The aim of this work was to investigate the role of cytosolic free calcium concentration ([Ca2+]i) and voltage-gated calcium influx in controlling growth cone behaviour and neurite elongation. [Ca2+]i and voltage-gated calcium influx was measured using digital imaging fluorescence microscopy (DIFM) and the whole-cell patch-clamp technique. The behaviour of growth cones of N IE-115 mouse neuroblastoma was observed and categorized into five classes. The spatial distribution of [Ca2+]i associated with these behavioural states was measured. True growth occurred only at the lowest levels. Any spontaneous elevation of [Ca2+]i above this level was associated with an inhibition of neurite elongation. Large elevations of [Ca2+]i were associated with specific morphological changes. L- and T-type voltage gated calcium currents were measured during differentiation. All cells possessing neurites had T-type currents. T-type current density was higher in cells with neurites than in cells without. There was no other detectable change in the characteristics of either current during differentiation. The spatial distribution of voltage-dependent calcium influx through L- and T-type channels was measured at the growth cone. L-type channels were found to be clustered in the growth cone membrane, whereas T-type channels were uniformly distributed. Activation of L-channel clusters caused [Ca2+]i 'hotspots' in which [Ca2+]i rose to micromolar levels during 1s depolarizations. Localized morphological changes at the site of the hotspot were observed during action potentials
Network structure within the cerebellar input layer enables lossless sparse encoding.
No full textThe synaptic connectivity within neuronal networks is thought to determine the information processing they perform, yet network structure-function relationships remain poorly understood. By combining quantitative anatomy of the cerebellar input layer and information theoretic analysis of network models, we investigated how synaptic connectivity affects information transmission and processing. Simplified binary models revealed that the synaptic connectivity within feedforward networks determines the trade-off between information transmission and sparse encoding. Networks with few synaptic connections per neuron and network-activity-dependent threshold were optimal for lossless sparse encoding over the widest range of input activities. Biologically detailed spiking network models with experimentally constrained synaptic conductances and inhibition confirmed our analytical predictions. Our results establish that the synaptic connectivity within the cerebellar input layer enables efficient lossless sparse encoding. Moreover, they provide a functional explanation for why granule cells have approximately four dendrites, a feature that has been evolutionarily conserved since the appearance of fish
Treasures of the University : an examination of the identification, presentation and responses to artefacts of significance at the University of St Andrews, from 1410 to the mid-19th century; with an additional consideration of the development of the portrait collection to the early 21st century
No full textSince its foundation between 1410 and 1414 the University of St Andrews has acquired what can be considered to be ‘artefacts of significance’. This somewhat nebulous phrase is used to denote items that have, for a variety of reasons, been deemed to have some special import by the University, and have been displayed or otherwise presented in a context in which this status has been made apparent.
The types of artefacts in which particular meaning has been vested during the centuries under consideration include items of silver and gold (including the maces, sacramental vessels of the Collegiate Church of St Salvator, collegiate plate and relics of the Silver Arrow archery competition); church and college furnishings; artworks (particularly portraits); sculpture; and ethnographic specimens and other items described in University records as ‘curiosities’ held in the University Library from c. 1700-1838.
The identification of particular artefacts as significant for certain reasons in certain periods, and their presentation and display, may to some extent reflect the University's values, preoccupations and aspirations in these periods, and, to some degree, its identity. Consciously or subconsciously, the objects can be employed or operate as signifiers of meaning, representing or reflecting matters such as the status, authority and history of the University, its breadth of learning and its interest and influence in spheres from science, art and world cultures to national affairs.
This thesis provides a comprehensive examination of the growth and development of the University's holdings of 'artefacts of significance' from its foundation to the mid-19th century, and in some cases (especially portraits) beyond this date. It also offers insights into how the University viewed and presented these items and what this reveals about the University of St Andrews, its identity, which changed and developed as the living institution evolved, and the impressions that it wished to project
Arctic Anti-Radio
No full text"Arctic Anti-Radio" is an essay which focuses on a series of field recordings made by the author that combine conventional microphones with sensor systems designed to capture the energies and dynamic properties of electro-magnetic radiation. These recordings were made in North Norway / Sápmi, a region where Norwegian energy infrastructure projects relating to hydro-electric and wind power are presented as part of a green transition away from a fossil fuel economy and yet have been met by resistance from Sámi and others who believe these structures pose threats to indigenous lives and places and to more-than-human populations such as birds (affected by wind turbines) and reindeer (affected by underground cables and acces routeways).
The essay describes these conflicts, the processes involved in recording the electro-magnetic energies of infrastructure and considers how an audio essay might develop that is beholden neither to the 'musical' as form nor to the voice as interpretative authority and nor to the sleeve or programme note as textual support. Is there an audio essay that can be lead by sound that has not been processed according to conventions of audibility? What kinds of expectation would such an approach place on its listeners? As the volume's introduction has it "Carlyle uses this as an opportunity to ask whether the audio essay continues to bow too much to the didacticism of the traditional essay form, clinging to insistently to fragments of the textual archive as anchors from which sound can take off".
The wider edited volume seeks to explore ideas of the 'audio essay,' a relatively new coining but a concept that resonates not just with cognate notions such as the video essay or film essay but with earlier forms of reflective thought in sonic form.
Other contributors, artists, philosophers, curators, include Lawrence Abu Hamdan, Lendl Barcelos, Justin Barton, Ben Borthwick, Matt Colquhoun, Jessica Edwards, Kodwo Eshun, Steve Goodman, Ayesha Hameed, Eleni Ikoniadou, Lawrence Lek, Robin Mackay, Paul Nataraj, Emily Pethick, Iain Sinclair and Shelley Trower
‘The Churchillian Paradigm and the “Other British Isles”: An Examination of Second World War Remembrance in Man, Orkney, and Jersey’
No full textThis dissertation studies Second World War ‘sites of memory’ in the islands of Jersey, Orkney and the Isle of Man, to determine if each island celebrates the war’s events as Britain does, or if they have charted their own mnemonic course. It builds on the work of Angus Calder, Malcolm Smith, and Mark Connelly, who have explored how popular conception of the Second World War in Britain has been structured around a certain set of commemorative motifs, most of which centre on Winston Churchill and the events of 1940. The British war narrative is now commonly referred to as the ‘Churchillian paradigm’ or ‘finest-hour myth’, and continues to be the driving force in commemoration and memorialization on the British mainland. The three islands in this study are culturally and historically distinct from Britain, and each has strong notions of its own ‘island identity’. Each also possesses a tangential and divisive domestic experience of war, one which is often minimized in the iconography of the Churchillian paradigm. Jersey was occupied by Nazi Germany from 1940 to 1945, Orkney was home to several thousand Italian POWs who built important infrastructure in the island, and the Isle of Man was home to 14,000 German, Finnish, Japanese, and Italian internees in what one critic has called ‘a bespattered page’ in the nation’s history. By examining ‘sites of memory’— museums, heritage sites, commemorations, celebrations, philately, and use of public space—this dissertation shows that each island simultaneously accepts and rejects elements of the finest-hour myth in their collective memory. Each island displays its unique (though often quite negative) heritage in order to differentiate itself from Britain, while at the same time allowing them, at certain events, to participate in celebration of Britain’s ‘greatest victory’. In this way, islands’ use ‘Britishness’ pragmatically, by basking in traditionally ‘British’ commemorative tropes, while at the same time deepening their own cultural and historical sovereignty
Materialising cultural value in the English lakes, 1735-1845 : a study of the responses of new landowners to representations of place and people
No full textThis thesis explores responses to the cultural construction in the developing identity of the English Lakes from 1735 to 1845, through studies of three landowners. The principal focus is Derwentwater. The Greenwich Hospital held estates from 1735 to 1832, Lord William Gordon from 1781 to 1823, and John Marshall of Leeds, the flax spinner, from 1810 and 1845. The study classifies the identity of the English Lakes and its inhabitants with Regions of Romance, as a territory increasingly occupied by the romantic antithesis of the dominant thesis within the modern age. The cultural identity of the English Lakes is considered as a construction of Throsby’s cultural values, established through discourse and overlaid upon economic values. This anthropological approach to culture recognises both aesthetic and social cultural assets. The acquisition, management and disposal of landowners estates are examined to evidence the materialisation of cultural values, whether through the agency of discourse, the influence of others, or personal experience. During the eighteenth century the Hospital responded to criticism minimally, by planting the Derwentwater shore. Lord William Gordon responded strongly to discourse by creating a picturesque park which demonstrated his taste and values, and by completing the picturesque occupation of Derwentwater by 1787. Wordsworth influenced the choice and management of John Marshall’s extensive estates from 1811, providing an early materialisation of the principles in Wordsworth’s Guide. In the early nineteenth century the Hospital protected their Keswick woods, before selling the estate in 1832 at auction to John Marshall at a low price. The study demonstrates a significant and growing intervention by these landowners to materialise aesthetic cultural value, but with little response to social cultural values, though cultural landscape was preserved. An early private path of intervention in the English Lakes is demonstrated, which feeds into the later and better known public path
‘ALLOW ME TO INTRODUCE MYSELF — FIRST, NEGATIVELY’: CHARLES DICKENS, ANTHONY TROLLOPE, WILLIAM MAKEPEACE THACKERAY AND FIRST-PERSON JOURNALISM IN THE 1860S FAMILY MAGAZINE
No full textThis thesis examines the editorial contributions of W.M. Thackeray, Charles Dickens and Anthony Trollope to the Cornhill Magazine, All the Year Round and Saint Pauls Magazine, analyzing their cultivation of a familiar or personal style of journalism in the context of the 1860s family magazine and its rhetoric of intimacy. Focusing on their first-person journalistic series, it argues that these writers/editors used these contributions as a means of establishing a seemingly intimate and personal relationship with their readers, and considers the various techniques that they used to develop that relationship, including their use of first-person narration, autobiography, the anecdote, dream sequences and memory. It contends that those same contributions questioned and critiqued the depiction of reader-writer relations which they simultaneously propagated, highlighting the distinction between this portrayal and the realities of the industrialized and commercialized world of periodical journalism. It places this within the context of the discourse of family that was integral to the identity of these magazines, demonstrating how these series both held up and complicated the idealized image of Victorian domesticity that was promoted by the mainstream periodical culture of the day, maintaining that this was a standard feature of family magazine journalism and theorizing that this was in fact a large part of its popular appeal to the family market. The introductory chapter examines the discourse of family that dominated the mid-range magazines of the 1860s and how this ties in with the series’ rhetoric of intimacy. Chapter One looks at Thackeray’s ‘Roundabout Papers’, examining the manner in which Thackeray establishes a sense of familiarity between his editorial persona and the reader, only to consistently undermine his own efforts, viewing this within the context of Thackeray’s realist aesthetic. Chapter Two turns to Dickens’s ‘The Uncommercial Traveller’, and traces the relationship between Dickens’s use of the personal, his concept of the ‘Uncommercial’ in the series and his preoccupation with the forces of commercialism and Utilitarianism, which it reads as ultimately concerned with his own sense of complicity in the commercialization of literature. Chapter Three studies ‘An Editor’s Tales’ within the context of its publication during the last months of Trollope’s editorship of Saint Pauls and reads the ambivalent relationship of the series to the personal and its unconventional treatment of the family in relation to this, viewing the series as a part of Trollope’s reaction to the failure of the experiment he undertook with Saint Pauls
Functional Properties of Dendritic Gap Junctions in Cerebellar Golgi Cells
No full textThe strength and variability of electrical synaptic connections between GABAergic interneurons are key determinants of spike synchrony within neuronal networks. However, little is known about how electrical coupling strength is determined due to the inaccessibility of gap junctions on the dendritic tree. We investigated the properties of gap junctions in cerebellar interneurons by combining paired somato-somatic and somato-dendritic recordings, anatomical reconstructions, immunohistochemistry, electron microscopy, and modeling. By fitting detailed compartmental models of Golgi cells to their somato-dendritic voltage responses, we determined their passive electrical properties and the mean gap junction conductance (0.9 nS). Connexin36 immunofluorescence and freeze-fracture replica immunogold labeling revealed a large variability in gap junction size and that only 18% of the 340 channels are open in each plaque. Our results establish that the number of gap junctions per connection is the main determinant of both the strength and variability in electrical coupling between Golgi cells
Taxing capital income in Hungary and the European Union
No full textCountries seeking membership in the European Union (EU) cannot look to the EU for a blueprint for reforming their system for taxing capital income. Indeed, it is hard to generalize about tax systems in the EU. Most member states apply fairly low tax rates to interest payments and discriminate against profit distributions. But tax rates, exemption levels, and methods of tax integration differ greatly within and across countries, and there is almost no harmonization of methods for taxing capital income. Approaches to taxing capital gains vary greatly, and distortions arise from the treatment of various sources of capital income. In 1993, when the EU began efforts to integrate capital markets, member countries proposed various ways to harmonize capital income taxes, including a proposal to introduce a withholding tax on interest income of residents of member states, with a minimum rate of 15 percent (revised to 10 percent). Under this scheme all interest on bank deposits and government and private bonds would be taxed and there might also be a final withholding tax on residents interest income. But the proposal was not accepted and the EU Commission decided to maintain the status quo, not to pressure member countries to harmonize company taxes. But Hungary could look for models in the Nordic countries (especially Norway and Sweden), Austria, and Finland, which have undertaken far-reaching reforms of capital income taxation. In most EU countries capital gains are either not (directly) taxed or are not taxed systematically. In Finland and Norway identical tax rates are applied to all types of capital income, including capital gains. The centerpiece of the"Scandinavian model"is a dual income tax, combining a progressive tax on personal income with a flat-rate tax on all types of capital income. The"Scandinavian model"contrasts sharply with the"comprehensive income taxation"model, under which a single (progressive) tax schedule is applied to income from all sources. In Austria the treatment of different types of capital income is relatively uniform but the composite tax burden on capital income resembles the highest personal income tax rate rather than a reduced rate. Austria's rate of tax evasion was high, but a 10 percent withholdingtax applied to all interest-bearing assets has reduced discrimination against honest taxpayers.Economic Theory&Research,Public Sector Economics&Finance,International Terrorism&Counterterrorism,Environmental Economics&Policies,Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,Public Sector Economics&Finance,International Terrorism&Counterterrorism,Banks&Banking Reform
Based on a true history?: The impact of popular "Medieval Film" on the public understanding of the Middle Ages
No full textThis thesis examines the understanding of the Middle Ages among the UK public and the impact that popular big-budget films which depict the period have on that understanding. Three films released between 2000 and 2009 are chosen for detailed study, their selection being determined by success at the UK box office as a measure of popularity: Lord of the Rings, Return of the King (Jackson, 2003), Kingdom of Heaven (Scott, 2005) and Beowulf (Zemeckis, 2007).
Ten focus group interviews were conducted with nineteen participants, all between eighteen and twenty-six years of age, none of whom had studied the Middle Ages at GCSE level (age 14-16) or higher. In these groups, participants discussed their knowledge of the Middle Ages, were shown a film, and then discussed what they had seen. Participants were asked open-ended interview questions to encourage them to respond in their own terms and define what was important to them. As a result, topics ranged widely. In preliminary discussions, participants discussed how they understood the period, their academic, experiential and pop-culture sources of knowledge, their definitions of the similar terms ‘medieval’ and ‘Middle Ages’ and also their ideas about medieval culture, religion, warfare and crusade. After the films, participants discussed what they had seen usually in the context of what they already knew, sometimes constructing false memories of what they had seen which fit with their previous knowledge. Often they used the language of historical veracity to criticise the film for other related reasons (like poor filmmaking or inappropriate accents). They found support for many of their historical misconceptions in the films, but, rather than accepting all they saw as historical truth, they engaged in a complex critical discourse with what they were shown.
The findings of this thesis have implications for medieval (and medievalism) studies, public history, and for the delivery of history in primary, secondary and higher education
- …
