1,093 research outputs found

    An application of Maurice Blanchot's notion of modern literature: to an analyses of P.B. Shelley's Alastor, Julian and Maddalo and the triumph of life

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    The thesis considers the parallel critiques of the notion of poesis as a mode of subjective power of self-determination in P.B. Shelley and Maurice Blanchot. It explores the terms in which, in the romantic-idealist tradition, the work of art is valorised as the realisation of the subject's access to spiritual significance. The thesis traces one of the sources of Blanchot's notion of modern literature' to his understanding of romanticism. It describes the ways in which Blanchot's notion of the non-romantic essence of romanticism deconstructs the romantic-idealist model of the work of literature as a mode of subjective self-realisation. Blanchot focuses on the fact that the presence of the critique of this model within the romantic/idealist theorization of the work of literature turns literature into a self-questioning, rather than a self-realizing structure. The idealist framework offers a notion of absolute reflection which significantly extends the model/figure of the autonomous subject. The thesis will argue that, on the evidence of some of Shelley’s prose fragments, the empiricist and sceptical heritage of Shelley' s conception of the mind draws him away from subscribing to such a model, and ultimately leads him to repeal it. The thesis will also argue that a similar undermining of the individual integrity of the subject can be observed in Shelley’s conception of self-identity. The analysis undertaken in the thesis concentrates on how a distinction between the ability to realize the poetical work and a process of self-realization is manifested in the three poems selected for scrutiny, and how this problematic is developed through the individual imaginative quest embodied in the figure of the poet in Alastor. The thesis will also explore the ways in which the ambivalence of the articulations around which the world of sanity and the notion of the accomplished work of literature are organized and dramatized in Julian and Maddalo. The Triumph of Life is then contrasted with the theme of the representative relation of the poet in concord to his community that is offered in A Defence of Poetry. In this poem, the principle of creation is likened to the course of history

    Natural age dispersion arising from the analysis of broken crystals, part II. Practical application to apatite (U-Th)/He thermochronometry

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    We describe a new numerical inversion approach to deriving thermal history information from a range of naturally dispersed single grain apatite (U-Th)/He ages. The approach explicitly exploits the information about the shape of the 4He diffusion profile within individual grains that is inherent in the pattern of dispersion that arises from the common and routine practice of analysing broken crystals. Additional dispersion arising from differences in grain size and in U and Th concentration of grains, and the resultant changes to helium diffusivity caused by differential accumulation and annealing of radiation damage, is explicitly included. In this approach we calculate the ingrowth and loss, due to both thermal diffusion and the effects of α-ejection, of helium over time using a finite cylinder geometry. Broken grains are treated explicitly as fragments of an initially larger crystal. The initial grain lengths, L0, can be treated as unknown parameters to be estimated, although this is computationally demanding. A practical solution to the problem of solving for the unknown initial grain lengths is to simply apply a constant and sufficiently long L0 value to each fragment. We found that a good value for L0 was given by the maximum fragment length plus two times the maximum radius of a given set of fragments. Currently whole crystals and fragments with one termination are taken into account. A set of numerical experiments using synthetic fragment ages generated for increasingly complex thermal histories, and including realistic amounts of random noise (5-15%), are presented and show that useful thermal history information can be extracted from datasets showing very large dispersion. These include experiments where dispersion arises only from fragmentation of a single grain (length 400Όm and radius 75Όm, c. 6-50% dispersion), including the effects of grain size variation (for spherical equivalent grain radii between 74-122 Όm, c. 10-70% dispersion) and the combined effects of fragmentation, grain size and radiation damage (for eU between 5-150 ppm, c.10-107% dispersion). Additionally we show that if the spherical equivalent radius of a broken grain is used as a measure of the effective diffusion domain for thermal history inversions then this will likely lead to erroneous thermal histories being obtained in many cases. The viability of the new technique is demonstrated for a real data set of 25 single grain (U-Th)/He apatite ages obtained for a gabbro sample from the BK-1 (Bierkraal) borehole drilled through the Bushveld Complex in South Africa. The inversion produces a well constrained thermal history consistent with both the (U-Th)/He data and available fission track analysis data. The advantage of the new approach is that it can explicitly accommodate all the details of conventional schemes, such as the effects of temporally variable diffusivity, zonation of U and Th and arbitrary grain size variations, and it works equally effectively for whole or broken crystals, and for the most common situation where a mixture of both are analysed. For the routine application of the apatite (U-Th)/He thermochronometry technique with samples where whole apatite grains are rare our experiments indicate that 15-20 single grain analyses are typically required to characterise the age dispersion pattern of a sample. The experiments also suggest that picking very short crystal fragments as well as long fragments, or even deliberately breaking long crystals to maximise the age dispersion in some cases, would ensure the best constraints on the thermal history models. The inversion strategy described in this paper is likely also directly applicable to other thermochronometers, such as the apatite, rutile and titanite U-Pb systems, where the diffusion domain is approximated by the physical grain size

    How research programs come apart: the example of supersymmetry and the disunity of physics

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    According to Peter Galison, the coordination of different ``subcultures'' within a scientific field happens through local exchanges within ``trading zones''. In his view, the workability of such trading zones is not guaranteed, and science is not necessarily driven towards further integration. In this paper, we develop and apply quantitative methods (using semantic, authorship, and citation data from scientific literature), inspired by Galison's framework, to the case of the disunity of high-energy physics. We give prominence to supersymmetry, a concept that has given rise to several major but distinct research programs in the field, such as the formulation of a consistent theory of quantum gravity or the search for new particles. We show that ``theory'' and `phenomenology'' in high-energy physics should be regarded as distinct theoretical subcultures, between which supersymmetry has helped sustain scientific ``trades''. However, as we demonstrate using a topic model, the phenomenological component of supersymmetry research has lost traction and the ability of supersymmetry to tie these subcultures together is now compromised. Our work supports that even fields with an initially strong sentiment of unity may eventually generate diverging research programs and demonstrates the fruitfulness of the notion of trading zones for informing quantitative approaches to scientific pluralism

    Oligocene-Miocene burial and exhumation of the Southern Pyrenean foreland quantified by low-temperature thermochronology

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    International audienceThe central Pyrenees experienced an episode of rapid exhumation in Late Eocene-Early Oligocene times. Erosional products shed from the range during this time were deposited in large palaeovalleys of the southern flank of the Axial Zone, leading to significant sediment accumulation. A recent numerical modelling study of the post-orogenic exhumation and relief history of the central Axial Zone allowed us to constrain this valley-filling episode in terms of timing and thickness of conglomeratic deposits. This paper aims to test these results for the southern fold-and-thrust belt using apatite fission-track and (U-Th)/He analysis on detrital samples from the Tremp-Graus and Ager basins. inverse thermal-history modelling of the low-temperature thermochronology data indicates that the fold-and-thrust belt was covered during the Late Eocene to Miocene by 0.7-1.6 km of sediments and confirms the timing of re-excavation of the valleys during the Miocene. A detailed analysis of the apatite (U-Th)/He results shows that the significant scatter in grain ages can be explained by the influence of alpha-recoil damage with varying effective uranium content together with distinct pre-depositional thermal histories; the age scatter is consistent with initial exhumation of the sediment sources during the Triassic and Early Cretaceous

    Retour sur une enquĂȘte du PRES UniversitĂ© Paris-Est : Pratiques informationnelles des chercheurs et des doctorants

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    Le rĂ©seau documentaire UPEdoc, composĂ© des services communs de documentation et services documentaires des Ă©tablissements membres du PRES UniversitĂ© Paris-Est, a initiĂ© en 2010 un projet de portail documentaire pour le dĂ©veloppement d\u27 une offre cohĂ©rente. Dans cette perspective, une Ă©tude a Ă©tĂ© diligentĂ©e en dĂ©cembre dernier auprĂšs des chercheurs et doctorants pour connaĂźtre leurs usages et besoins en matiĂšre documentaire. Elle a rencontrĂ© un intĂ©rĂȘt certain puisque sur les 3 000 chercheurs et doctorants sollicitĂ©s, prĂšs de 800 rĂ©ponses ont Ă©tĂ© enregistrĂ©es. Elles doivent permettre de dessiner la configuration d\u27un portail adaptĂ© Ă  la communautĂ© des chercheur

    Innovations in (U–Th)/He, Fission Track, and Trapped Charge Thermochronometry with Applications to Earthquakes, Weathering, Surface‐Mantle Connections, and the Growth and Decay of Mountains

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    A transformative advance in Earth science is the development of low‐temperature thermochronometry to date Earth surface processes or quantify the thermal evolution of rocks through time. Grand challenges and new directions in low‐temperature thermochronometry involve pushing the boundaries of these techniques to decipher thermal histories operative over seconds to hundreds of millions of years, in recent or deep geologic time and from the perspective of atoms to mountain belts. Here we highlight innovation in bedrock and detrital fission track, (U–Th)/He, and trapped charge thermochronometry, as well as thermal history modeling that enable fresh perspectives on Earth science problems. These developments connect low‐temperature thermochronometry tools with new users across Earth science disciplines to enable transdisciplinary research. Method advances include radiation damage and crystal chemistry influences on fission track and (U–Th)/He systematics, atomistic calculations of He diffusion, measurement protocols and numerical modeling routines in trapped charge systematics, development of 4He/3He and new (U–Th)/He thermochronometers, and multimethod approaches. New applications leverage method developments and include quantifying landscape evolution at variable temporal scales, changes to Earth\u27s surface in deep geologic time and connections to mantle processes, the spectrum of fault processes from paleoearthquakes to slow slip and fluid flow, and paleoclimate and past critical zone evolution. These research avenues have societal implications for modern climate change, groundwater flow paths, mineral resource and petroleum systems science, and earthquake hazards

    Submarine networks: evolution, not revolution

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    Early Cenozoic denudation of central west Britain in response to transient and permanent uplift above a mantle plume

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    Upwelling mantle plumes beneath continental crust are predicted to produce difficult to quantify, modest uplift and denudation. The contribution of permanent and transient components to the uplift is also difficult to distinguish. A pulse of denudation in Britain in the Early Paleogene has been linked, although with some controversy, with the arrival of the proto-Iceland mantle plume. In this contribution we show that combining apatite and zircon (U-Th-Sm)/He and apatite fission track analyses from central west Britain with numerical modeling clearly identifies a pulse of early Cenozoic denudation. The data indicate that rock uplift and denudation were centered on the northern East Irish Sea Basin and 1.0–2.4 km of rocks were removed during the latest Cretaceous-early Paleogene. Uplift and erosion appears to have started a few million years before the earliest magmatism in the region. The regional denudation pattern mirrors the distribution of low-density magmatic rocks that has been imaged in the deep crust. However, the injection of the underplating melt is not enough to account for the total denudation. An additional regional uplift of at least 300 m is required, which is consistent with a transient thermal effect from the hot mantle plume. The rapid exhumation event ceased by ~40 Ma and the data do not require significant Neogene exhumation

    Relations between cognition and motricity in children with neonatal arterial ischemic stroke

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    Introduction and goalPerinatal arterial ischemic stroke (PAIS) affects one child for 4000 births. The few studies about cognitive development specific to PAIS showed that cognitive performances in this population do not follow up a normal development (Westmacott et al., 2010; Ricci et al., 2008). Based on new data about relation between motricity and cognition (Smits-Engelsman et Hill, 2012), and on the theory of the embodied cognition, led us to hypothesize that cognitive performances would be correlated to the motor performances in children with PAIS.Patients and methodologyWe tested 77 7 years old children meeting the criteria of neonatal AIS, with a diagnosis before the 28th day of life relying on cerebral imagery. After excluding children with seizure and bi-hemispheric lesion, 56 children participated to our study. The cognitive evaluation was performed with the Wechsler Intelligence Scale for Children (WISC-4), the motor evaluation relied on testing of gross motor of the upper arm (Box and Block Test) and fine prehension test (“Nine Hole Peg Test”). The localisation of the lesion, the economic level of parents, the gender, sensory impairments and the presence of hemiplegia were collected. We analyzed these results with simple linear regression.ResultsThe main result of our study is the significative correlation (P<0.03) between scores of the WISC4 (except for working memory index) and motor results. In contrast we did not find any correlation between the scores of the WISC4 and the presence of hemiplegia or with lesion localization.DiscussionMany brain networks develop during the first year through sensorimotor experiences, which contribute to the emergence of knowledge. This concept of development, supported by the approach embodied cognition, can explain the correlations between cognition and motor found in our work and in several studies with children with other early neurological damage
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