3,189 research outputs found

    Derek Mahon's Seascapes Mediated through Greece: Antiquity in Modernity, Nature in Abstraction.

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    The article investigates various approaches to seascape in selected poems of the contemporary Irish poet, Derek Mahon, set against the background of references to Michael Longley, Seamus Heaney or Odysseus Elytis. The sea provides a perspective that cannot be overestimated in trying to get an insight into the communication and the clash between the culture of the South and the North. The two nations have often glimpsed at their reflection in the mirror of the surrounding seas, their history and mentality determined by their geographical position and largely insular experience. Elements such as the isolation from the mainland; the perception of the sea as a personification of the force ruling over life and death, as a threat and a promise; or the focus on some characteristic natural phenomena such as light or surface dominate the seascape imagery both in Greek and Irish literature. The sea often constitutes a border of antagonistic and complementary worlds: dream and reality, light and darkness, male and female, the real world and the underworld – and the vantage point of the poet changes accordingly. Some poems under discussion also explore a series of myths linked with the sea, the best known of which, the Odyssey, has remained a frame of reference for numerous contemporary Greek and Irish poets. Elytis's Cyclades or Longley's Mayo provide us with examples of 'private homelands'. As Longley once observed, “his part of Mayo” reminds him of Ithaca (sandy and remote) and of Greece in general: “I’ve often thought that that part of Ireland . . . looks like Greece. Or Greece looks like a dust-bowl version of Ireland,” which triggers further deliberations on seascape as the common ground for the two countries. Just as Elytis's Cyclades or Longley's Mayo, Mahon’s Cyclades provide us with examples of 'private homelands'. The focus of this article is Derek Mahon’s seascapes: purely Greek (‘Aphrodite’s Pool’), Irish seen through the prism of the Greek ones (‘Achill’) and purely Irish (‘Recalling Aran’). The level of abstraction in the last category is compared with Odysseus Elytis’s imagery of the Cyclades, while the first poem demystifies a practice which I termed as ‘myth trading’, one of consumerist tourism techniques

    Analysis of nitrogen tetroxide samples Final report

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    Chemical analysis of nitrogen tetroxide trace impuritie

    An experimental investigation of the flow fields about delta and double-delta wings at low speeds

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    Low speed wind tunnel analysis of flow fields about delta and double delta wing

    Further experimental investigations of delta and double-delta wing flow fields at low speeds

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    Low speed wind tunnel investigations of delta and double-delta wing flow fields and relationship to aerodynamic forc

    Learning intrinsic excitability in medium spiny neurons

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    We present an unsupervised, local activation-dependent learning rule for intrinsic plasticity (IP) which affects the composition of ion channel conductances for single neurons in a use-dependent way. We use a single-compartment conductance-based model for medium spiny striatal neurons in order to show the effects of parametrization of individual ion channels on the neuronal activation function. We show that parameter changes within the physiological ranges are sufficient to create an ensemble of neurons with significantly different activation functions. We emphasize that the effects of intrinsic neuronal variability on spiking behavior require a distributed mode of synaptic input and can be eliminated by strongly correlated input. We show how variability and adaptivity in ion channel conductances can be utilized to store patterns without an additional contribution by synaptic plasticity (SP). The adaptation of the spike response may result in either "positive" or "negative" pattern learning. However, read-out of stored information depends on a distributed pattern of synaptic activity to let intrinsic variability determine spike response. We briefly discuss the implications of this conditional memory on learning and addiction.Comment: 20 pages, 8 figure

    Editors' Review and Introduction:Lying in Logic, Language, and Cognition

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    We describe some recent trends in research on lying from a multidisciplinary perspective, including logic, philosophy, linguistics, psychology, cognitive science, behavioral economics, and artificial intelligence. Furthermore, we outline the seven contributions to this special issue of topiCS.</p

    Spectral Karyotyping for identification of constitutional chromosomal abnormalities at a national reference laboratory

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    Spectral karyotyping is a diagnostic tool that allows visualization of chromosomes in different colors using the FISH technology and a spectral imaging system. To assess the value of spectral karyotyping analysis for identifying constitutional supernumerary marker chromosomes or derivative chromosomes at a national reference laboratory, we reviewed the results of 179 consecutive clinical samples (31 prenatal and 148 postnatal) submitted for spectral karyotyping. Over 90% of the cases were requested to identify either small supernumerary marker chromosomes (sSMCs) or chromosomal exchange material detected by G-banded chromosome analysis. We also reviewed clinical indications of those cases with marker chromosomes in which chromosomal origin was identified by spectral karyotyping. Our results showed that spectral karyotyping identified the chromosomal origin of marker chromosomes or the source of derivative chromosomal material in 158 (88%) of the 179 clinical cases; the identification rate was slightly higher for postnatal (89%) compared to prenatal (84%) cases. Cases in which the origin could not be identified had either a small marker chromosome present at a very low level of mosaicism (< 10%), or contained very little euchromatic material. Supplemental FISH analysis confirmed the spectral karyotyping results in all 158 cases. Clinical indications for prenatal cases were mainly for marker identification after amniocentesis. For postnatal cases, the primary indications were developmental delay and multiple congenital anomalies (MCA). The most frequently encountered markers were of chromosome 15 origin for satellited chromosomes, and chromosomes 2 and 16 for non-satellited chromosomes. We were able to obtain pertinent clinical information for 47% (41/88) of cases with an identified abnormal chromosome. We conclude that spectral karyotyping is sufficiently reliable for use and provides a valuable diagnostic tool for establishing the origin of supernumerary marker chromosomes or derivative chromosomal material that cannot be identified with standard cytogenetic techniques

    Chaos and the continuum limit in the gravitational N-body problem II. Nonintegrable potentials

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    This paper continues a numerical investigation of orbits evolved in `frozen,' time-independent N-body realisations of smooth time-independent density distributions corresponding to both integrable and nonintegrable potentials, allowing for N as large as 300,000. The principal focus is on distinguishing between, and quantifying, the effects of graininess on initial conditions corresponding, in the continuum limit, to regular and chaotic orbits. Ordinary Lyapunov exponents X do not provide a useful diagnostic for distinguishing between regular and chaotic behaviour. Frozen-N orbits corresponding in the continuum limit to both regular and chaotic characteristics have large positive X even though, for large N, the `regular' frozen-N orbits closely resemble regular characteristics in the smooth potential. Viewed macroscopically both `regular' and `chaotic' frozen-N orbits diverge as a power law in time from smooth orbits with the same initial condition. There is, however, an important difference between `regular' and `chaotic' frozen-N orbits: For regular orbits, the time scale associated with this divergence t_G ~ N^{1/2}t_D, with t_D a characteristic dynamical time; for chaotic orbits t_G ~ (ln N) t_D. At least for N>1000 or so, clear distinctions exist between phase mixing of initially localised orbit ensembles which, in the continuum limit, exhibit regular versus chaotic behaviour. For both regular and chaotic ensembles, finite-N effects are well mimicked, both qualitatively and quantitatively, by energy-conserving white noise with amplitude ~ 1/N. This suggests strongly that earlier investigations of the effects of low amplitude noise on phase space transport in smooth potentials are directly relevant to real physical systems.Comment: 20 pages, including 21 FIGURES, uses RevTeX macro
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