2,477 research outputs found

    The curse of Frankenstein: visions of technology and society in the debate over new reproductive technologies

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    At each successive moment in their development new reproductive technologies have provided the occasion for virulent argument about the role of technology in human affairs. And more generally, technoscientific knowledge has long been held both in awe and suspicion, with the latter acting as a kind of counterbalance to the continuing cultural investment in the image of scientific knowledge as empowerment, as the motive force of beneficial change. Given this cultural ambivalence the paper focuses on media representations of cloning and the 'designer baby' (with the latter enveloping a debate that has run for almost a decade now) and explores the ways utopian images of a world rendered ever more amenable to human desires have been closely shadowed by just as compelling dystopian visions which are nevertheless constructed from the same cultural material. Figures of occidental folklore such as Frankenstein (or Jeckyll or Brave New World), thus function as something of a convenient shorthand for articulating unease with the direction and pace of technological development, or even voicing loss of confidence in the modernist technoscientific project of instrumental control. In these circumstances, the chimeric notions of the 'designer baby' or the human 'clone' appear Janus-faced, concurrently representing the powers of human creativity as well as the monstrous progeny of an excessive epistemophilia. They are in this sense potent metaphors for the biotechnological revolution's declared power to re-shape both nature and society - for 'good' or 'ill'

    When is an Affordance? Bodies, Technologies and Action Possibilities

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    Borrowed from ecological psychology, the concept of affordances is often said to offer the social study of technology a means of re-framing the question of what is, and what is not, 'social' about technological artefacts. The concept, many argue, enables us to chart a safe course between the perils of technological determinism and social constructivism. The debate is still ongoing and this paper is a contribution to it. Drawing on ethnographic work on the ways technological artefacts engage, and are engaged by disabled bodies, we propose that the 'affordances' of such objects are not reducible to their material constitution but are inextricably bound up with specific, historically situated modes of engagement and ways of life

    Glacial and Postglacial History of the White Cloud Peaks-Boulder Mountains, Idaho, U.S.A.

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    Glacial and glaciofluvial deposits are mapped and differentiated to develop new local, relative-age (RD) stratigraphies for the North Fork of the Big Lost River, Slate Creek and Pole Creek drainages in the White Cloud Peaks and Boulder Mountains, Idaho. This stratigraphic model expands the areal extent of the "Idaho glacial model". Volcanic ash samples collected from the study area are petrographically characterized and correlated, on the basis of mineralogy and glass geochemistry, to reference samples of identified Cascade Range tephras. Four distinct tephras are recognized including; Mount St. Helens-Set S (13,600-13,300 yr BP), Glacier Peak-Set B (11,250 yr BP), Mount Mazama (6600 yr BP) and Mount St. Helens-Set Ye (4350 yr BP). A core of lake sediments containing two tephra units was obtained from a site called "Pole Creek kettle". Pollen and sediment analyses indicate three intervals of late Pleistocene and Holocene climatic change. Cool and wet climatic conditions prevailed in the region shortly before and immediately following the deposition of the Glacier Peak-Set B ash (11,250 yr BP). Climatic warming occurred from approximately 10,500 to 6600 yr BP after which warm, dry conditions prevailed. Sediment accumulation in the kettle ceased by 4350 yr BP. The presence of Glacier Peak-Set B tephra in the base of the Pole Creek kettle core provides a minimum age of 11,250 yr BP for the retreat of valley glaciers from their Late Wisconsinan maximum position. A radiocarbon date of 8450 + 85 yr BP (SI-5181), and the presence of Mount Mazama ash (6600 yr BP) up-core support the Glacier Peak-Set B identification.La cartographie et l'identification des dépÎts glaciaires et fluvioglaciaires a permis d'établir la stratigraphie locale des bassins du North Fork de la Big Lost River, du Pole Creek et du Slate Creek. Le modÚle stratigraphique établi augmente la superficie déjà couverte par le modÚle glaciaire de l'Idaho. Les échantillons de cendre volcanique prélevés ont été identifiés sur le plan pétrographique et mis en corrélation avec des tephras témoins provenant du Cascade Range, en se fondant sur la composition minérale et sur la géochimie du verre. On distingue quatre types de tephras: ceux de la série S du mont St. Helen's (13 600-13 300 BP), ceux de la série B du Glacier Peak (11 250 BP), ceux de la série S du mont St. Helen's (4350 BP) et ceux du mont Mazama (6600 BP). Une carotte de sédiments lacustres prélevée dans le kettle Pole Creek renferme deux tephras. L'analyse du pollen et des sédiments révÚle l'existence de trois grands changements climatiques au Pleistocene supérieur et à l'HolocÚne: un climat frais et humide un peu avant et immédiatement aprÚs la mise en place des cendres de la série B du Glacier Peak (11 250 BP); une période de réchauffement (10 500-6600 BP); un climat chaud et sec. L'accumulation de sédiments dans le kettle prit fin vers 4350 BP. La présence du tephra de la série B du Glacier Peak à la base de la carotte donne la date minimale du retrait des glaciers de vallée (11 250 BP) à partir de leur emplacement au Wisconsinien supérieur. La date de 8450 + 85 ans BP et la présence, dans la partie supérieure de la carotte, de cendres provenant du mont Mazama (6600 BP) confirment l'identification de la série B du Glacier Peak.Idaho, U.S.A. Glaziale und glaziofluviale Ablagerungen wurden kartographiert und identifiziert, um eine neue, lokale, relative Alters-Stratigraphie der North Fork des Big Lost River, des Slate Creek und des Pole Creek in den White Cloud Peaks und Boulder Mountains, Idaho, zu en-twickeln. Proben vulkanischer Asche, die im untersuchten Gebiet gesammelt wurden, werden petrographisch bestimmt und auf der Basis von mineralogischer Zusammensetzung und Geochemie des Glases in Wechselbe-ziehung zu Referenz-Belegen von identifi-zierten Tephras von den Cascade Ranges gesetzt. Es werden vier verschiedene Tephras identifiziert: von der Série S des Mount St. Helens (13 600-13 300 v.u.Z.), von der Série B des Glacier Peak (11 250 v.u.Z.), von der Série Ye des Mount Mazama (6600 v.u.Z.) und des Mount St. Helens (4350 v.u.z.). Eine Probe von See-Sedimenten, der vom Pole Creek Kettle gewonnen wurde, enthùlt zwei Tephra-Einheiten. Die Pollen- und Sediment-Analysen lassen drei Intervalle klimatischen Wechsels im spùten Pleistozùn und im Ho-lozan erkennen. Kalte und feuchte Klimatische Bedingungen herrschten in diesem Gebiet vor, kurz vor und unmittelbar nach der Ablagerung der Asche der Série B des Glacier Peak (11 250 v.u.Z.). Eine klimatische Erwàrmung trat zwischen ungefàhr 10 500 bis 6600 v.u.Z. auf, nach welcher warme, trockene Bedingungen vorherrschten. Die Sediment-An-hàufung in dem Kettel endete ungefàhr um 4350 v.u.Z. Das Vorkommen von Tephra der Série B des Glacier Peak in der Basis der Probe des Pole Creek Kettle ergibt ein Minimum-Alter von 11 250 v.u.Z. fur den Ruckzug der Gletscher des TaIs von ihrer maximalen Position im spùten Wisconsin. Ein Radiokar-bon-Datum von 8450 + 85 v.u.Z. (SI-5181) und das Vorkommen von Asche des Mount Mazama (6600 v.u.Z.) im oberen Teil der Probe stutzen die Identifizierung der Série B des Glacier Peak

    Can Strong Gravitational Lensing Constrain Dark Energy?

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    We discuss the ratio of the angular diameter distances from the source to the lens, DdsD_{ds}, and to the observer at present, DsD_{s}, for various dark energy models. It is well known that the difference of DsD_ss between the models is apparent and this quantity is used for the analysis of Type Ia supernovae. However we investigate the difference between the ratio of the angular diameter distances for a cosmological constant, (Dds/Ds)Λ(D_{ds}/D_{s})^{\Lambda} and that for other dark energy models, (Dds/Ds)other(D_{ds}/D_{s})^{\rm{other}} in this paper. It has been known that there is lens model degeneracy in using strong gravitational lensing. Thus, we investigate the model independent observable quantity, Einstein radius (ΞE\theta_E), which is proportional to both Dds/DsD_{ds}/D_s and velocity dispersion squared, σv2\sigma_v^2. Dds/DsD_{ds}/D_s values depend on the parameters of each dark energy model individually. However, (Dds/Ds)Λ−(Dds/Ds)other(D_{ds}/D_s)^{\Lambda} - (D_{ds}/D_{s})^{\rm{other}} for the various dark energy models, is well within the error of σv\sigma_v for most of the parameter spaces of the dark energy models. Thus, a single strong gravitational lensing by use of the Einstein radius may not be a proper method to investigate the property of dark energy. However, better understanding to the mass profile of clusters in the future or other methods related to arc statistics rather than the distances may be used for constraints on dark energy.Comment: 15 pages, 13 figures, Accepted in PR

    Attractive Interactions Between Rod-like Polyelectrolytes: Polarization, Crystallization, and Packing

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    We study the attractive interactions between rod-like charged polymers in solution that appear in the presence of multi-valence counterions. The counterions condensed to the rods exhibit both a strong transversal polarization and a longitudinal crystalline arrangement. At short distances between the rods, the fraction of condensed counterions increases, and the majority of these occupy the region between the rods, where they minimize their repulsive interactions by arranging themselves into packing structures. The attractive interaction is strongest for multivalent counterions. Our model takes into account the hard-core volume of the condensed counterions and their angular distribution around the rods. The hard core constraint strongly suppresses longitudinal charge fluctuations.Comment: 4 figures, uses revtex, psfig and epsf. The new version contains a different introduction, and the bibliography has been expande

    Charge Fluctuations on Membrane Surfaces in Water

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    We generalize the predictions for attractions between over-all neutral surfaces induced by charge fluctuations/correlations to non-uniform systems that include dielectric discontinuities, as is the case for mixed charged lipid membranes in an aqueous solution. We show that the induced interactions depend in a non-trivial way on the dielectric constants of membrane and water and show different scaling with distance depending on these properties. The generality of the calculations also allows us to predict under which dielectric conditions the interaction will change sign and become repulsive

    High-Frequency Oscillations in a Solar Active Region observed with the Rapid Dual Imager

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    High-cadence, synchronized, multiwavelength optical observations of a solar active region (NOAA 10794) are presented. The data were obtained with the Dunn Solar Telescope at the National Solar Observatory/Sacramento Peak using a newly developed camera system : the Rapid Dual Imager. Wavelet analysis is undertaken to search for intensity related oscillatory signatures, and periodicities ranging from 20 to 370 s are found with significance levels exceeding 95%. Observations in the H-alpha blue wing show more penumbral oscillatory phenomena when compared to simultaneous G-band observations. The H-alpha oscillations are interpreted as the signatures of plasma motions with a mean velocity of 20 km/s. The strong oscillatory power over H-alpha blue-wing and G-band penumbral bright grains is an indication of the Evershed flow with frequencies higher than previously reported.Comment: 9 pages, 9 figure
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