3,778 research outputs found

    Drawing machines, bathing machines, motorbikes, the stars…: where are the masterpieces?

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    The term ‘digital drawing’ may imply a special kind of drawing, set against a natural approach. Previous generations also had to adjust to the new technologies of the time. Some resisted, some went ahead. New methods present difficulties as well as opportunities. The how-to-draw books of the 1900’s show not just one ‘traditional’ approach, but a wide range, and a healthy debate. For the past two centuries such books have here and there discussed both drawing machines, and the connected question of how to draw machines. One way or another the world of drawing will absorb the impact of computers, and it won’t be just as an isolated genre of slightly weird drawing. So it is wrong to exclude ‘digital’ drawing from surveys, to think of this category as distinct from mainstream drawing. Museums have already collected the significant works, and traced the history. The way forward should be to integrate digital tools within the broad spectrum of drawing types. There are no good reasons for not using digital devices, and no good reasons for not using pencils. All the same, I cite three cases where a pencil and paper technique would not be up to the job: football, a drawing jam session, and astronomy

    A drawing book for digital eyes

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    Looking at book covers may not tell you everything, but they do tell you something. A collection of leather-bound ‘how to draw’ books of the nineteen twenties exudes confidence, the expertise of the masters handed down. The titles indicate attention to technique, referring to ‘pencil drawing’, ‘lead pencil drawing’, or ‘pen and ink’, and speak of the ‘art’ of drawing. Some of these had been in print for fifty years. There are idealised classical figures, nature studies, but also stirrings of a more liberal approach. By the nineteen forties and fifties the books are less formal, less symmetrical, and more Do-It-Yourself: ‘I wish I could draw’, ‘Drawing at Home’, ’The Natural Way to Draw’, ‘Drawing Without a Master’. Some are slim volumes running in series devoted to subjects such as ships, cats, trees, even tanks. You draw the world around you

    Cash in a housing context: Transitional shelter and recovery in Japan

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    This paper presents city dwellers and local authorities with questions that international humanitarian organisations (IHOs) may not ask after massive housing destruction. We examine Japan's transitional shelter strategy following the 2011 Great East Japan Earthquake and Tsunami (GEJET) against these questions: who decides when and where to build housing; what is built, how and by whom; who finances, owns or rents; and how might such conditions affect disaster response? The analysis puts strategy in context by combining data on housing, subsidies and insurance, rather than presenting shelter delivery in isolation. In Japan, systemic housing-related vulnerabilities preceded the GEJET; shelter was a time-limited accommodation service; and cash hand-outs were not a cultural norm, not intended to be sufficient and never equivalent to the cost of temporary housing units. We argue that such analysis is needed to challenge IHO thinking and uncover specific historical, regulatory and personal housing trajectories following a disaster

    Central dark matter trends in early-type galaxies from strong lensing, dynamics and stellar populations

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    We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift (z ~ 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z ~ 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano, Romanowsky & Tortora (2010) and suggest negligible evidence of galaxy evolution over the last ~ 2.5 Gyr other than passive stellar aging.Comment: 5 pages, 3 figures, accepted for publication on ApJL. Version including further updates and a complementary note added in proo

    Correcting 'a notional' confusion for critical discourse analysis

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    The meaning and grammatical status of ‘a notional’ in the schema for critical discourse analysis (CDA) from Bhaskar’s posthumously published Enlightened Common Sense (2016) is somewhat ambiguous. An ambiguity that has persisted through a subsequent development of the schema. Following the publication of Bhaskar’s original manuscript, it can now be seen that erroneous grammatical changes were made to the manuscript during the publication process. The original version provides a more coherent schema for CDA. This paper discusses the implications of the original version coming to light. This shows that Bhaskar created a more coherent schema for CDA than the published version indicated. Clarifying the meaning and grammatical status of ‘a notional’ in Bhaskar’s schema for CDA and a schema that was subsequently derived from it is an important corrective for future critical realist critical discourse analysts

    Slip distributions on active normal faults measured from LiDAR and field mapping of geomorphic offsets: an example from L\u2019Aquila, Italy, and implications for modelling seismic moment release

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    Surface slip distributions for an active normal fault in central Italy have been measured using terrestrial laser scanning (TLS), in order to assess the impact of changes in fault orientation and kinematics when modelling subsurface slip distributions that control seismic moment release. The southeastern segment of the surface trace of the Campo Felice active normal fault near the city of L\u2019Aquila was mapped and surveyed using techniques from structural geology and using TLS to define the vertical and horizontal offsets of geomorphic slopes since the last glacial maximum (15 \ub13 ka). The fault geometry and kinematics measured from 43 sites and throw/heave measurements from geomorphic offsets seen on 250 scarp profiles were analysed using a modification of the Kostrov equations to calculate the magnitudes and directions of horizontal principal strain-rates. The map trace of the studied fault is linear, except where a prominent bend has formed to link across a former left-stepping relay-zone. The dip of the fault and slip direction is constant across the bend. Throw-rates since 15 \ub13 ka decrease linearly from the fault centre to the tip, except in the location of the prominent bend where higher throw rates are recorded. Vertical coseismic offsets for two palaeoearthquake ruptures seen as fresh strips of rock at the base of the bedrock scarp also increase within the prominent bend. The principal strain-rate, calculated by combining strike, dip, slip-direction and post 15 \ub13 ka throw, decreases linearly from the fault centre towards the tip; the strain-rate does not increase across the prominent fault bend. The above shows that changes in fault strike, whilst having no effect on the principal horizontal strain-rate, can produce local maxima in throw-rates during single earthquakes that persist over the timescale of multiple earthquakes (15 \ub13 ka). Detailed geomorphological and structural investigation of active faults is therefore a critical input in order to properly define fault activity for the purpose of accurate seismic hazard assessment. We discuss the implications of modelling subsurface slip distributions for earthquake ruptures through inversion of GPS, InSAR and strong motion data using planar fault approximations, referring to recent examples on the nearby Paganica fault that ruptured in the Mw 6.3 2009 L\u2019Aquila Earthquak

    Band Distributions for Quantum Chaos on the Torus

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    Band distributions (BDs) are introduced describing quantization in a toral phase space. A BD is the uniform average of an eigenstate phase-space probability distribution over a band of toral boundary conditions. A general explicit expression for the Wigner BD is obtained. It is shown that the Wigner functions for {\em all} of the band eigenstates can be reproduced from the Wigner BD. Also, BDs are shown to be closer to classical distributions than eigenstate distributions. Generalized BDs, associated with sets of adjacent bands, are used to extend in a natural way the Chern-index characterization of the classical-quantum correspondence on the torus to arbitrary rational values of the scaled Planck constant.Comment: 12 REVTEX page

    Mechanics of continental extension from Quaternary strain fields in the Italian Apennines

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    Horizontal upper crustal surface strain-rates calculated using slip-vectors from striated faults and offsets of Late Pleistocene-Holocene landforms and sediments are used to investigate the mechanisms responsible for deformation in the Italian Apennines over a variety of length-scales ranging from individual fault segments up to the width of the mountain range. The method used allows strain-rates in any 5km \times 5km grid square or combination of these grid squares to be calculated. This allows comparison of strain-rates from 15 \pm 3 kyrs of slip with those from shorter time periods within polygons that are comparable in size, shape and location with those imposed by geodetic station locations or moment summation calculations. Strain-rates over a time period of 15 \pm 3 kyrs from 5km \times 5km grid squares integrated over an area of 1.28 \times 10^4 km^2 (80km \times 160 km), show the horizontal strain-rate of the Lazio-Abruzzo region of the central Apennines is 1.18^{+0.12} _{-0.04}\times10^{-8}yr^{-1} and -1.83^{+3.80} _{-4.43}\times10^{-10}yr^{-1} parallel and perpendicular to the regional principal strain direction (043^o-223^o \pm 1^o), associated with extension rates of \leq3.1^{+0.7} _{-0.4} mm yr^{-1} if calculated in boxes with a 5km width and 90km length across the Apennines. In Molise-North Campania, the horizontal principal strain-rate calculated over an area of 5\times10^3 km^2 (50km\times100 km) is 2.11^{+1.14} _{-0.16}\times10^{-9} yr^{-1} along the horizontal axis parallel to 039^o - 219^o \pm 3^o, and 0.88^{+2.84}_{-1:30}\times10^{-10} yr^{-1} perpendicular to it, associated with extension rates of \leq0.2^{+0.2} _{-0.1} mm yr^{-1} if calculated in 5km \times 90km transects that cross the Apennines. Within the South Campania-Basilicata region of the southern Apennines of area 8 \pm 103 km2 (50km_160 km), the average horizontal strain-rate over 15 \pm 3 kyrs is 3.70\pm0.26\times10^{-9} yr^{-1} parallel to and 3.65\pm2.05\times10^{-10} mmyr^{-1} perpendicular to the principal strain axis (044^o-224^o\pm2^o), associated with extension rates of \leq0.6\pm0.2mmyr^{-1} if calculated in 5km\times90km transects across the Apennines. The same method is used to calculate strain-rates in Calabria from longerterm offset geological features (\leq 580 ka); the horizontal principal strain-rate calculated over an area of 8\times103 km^2 (40km\times200 km) is 6.71\pm2.13\times10^{-9} yr^{-1} along the horizontal axis parallel to 086^o-226^o\pm3^o, and -8.40\pm5.69\times10^{-10} yr^{-1} perpendicular to it. Strain-rates calculated over 15\pm3 kyrs within 5km\times5km grid squares vary from zero up to 2.34\pm0.54\times10^{-7} yr^{-1}, 3.69\pm1.33\times10^{-8} yr^{-1}, and 1.20\pm0.41\times10^{-7} yr^{-1} in the central Apennines, the Molise-North Campania region, and the southern Apennines, respectively. These strain-rates resolve variations in strain orientations and magnitudes along the strike of individual faults and are used to produce a fault specific earthquake recurrence interval map. In order to study the existence of possible deficits or surpluses of geodetic and earthquake strain in the Apennines, these 15 \pm 3 kyrs multi seismic cycle strain-rates have been compared to short-term strain-rates calculated using geodesy (over 126 yrs, 11 yrs and 5 yrs) and seismic moment summation (over 700 yrs). Regional strain-rates calculated from geodesy and historical earthquakes are greater than those calculated from offset 15 \pm 3 ka landforms and sediments. In detail, 10^{1-2} yr strain-rates are higher than 10^4 yr strain-rates in some small areas (\approx2000 km^2, corresponding to polygons defined by geodesy campaigns and seismic moment summations) with the opposite situation in other areas where seismic moment release rates in large (Ms>6.0) magnitude historical earthquakes have been reported to be as low as zero. This demonstrates (1) the importance of comparing the exact same areas, and (2) that strain-rates vary spatially on the length-scale of individual faults and on a timescale between 10^{1-2} yrs and 10^4 yrs in the Apennines. The results are used to discuss temporal earthquake clustering and the natural variability of the seismic cycle. Spatial variations in upper crustal strain-rate measured across exposed fault scarps since 15\pm3 ka are also used to discuss the regional deformation related to plate boundary and sub-crustal forces, specifically, whether mantle upwelling and uplift contribute to forces associated with the active extension in the Italian Apennines. Strain-rates calculated in 5km \times 90km boxes across the Apennines are compared with data on cumulative upper-crustal strain, topography, free-air gravity and SKS splitting delay times that are a proxy for strain in the mantle. High extension-rates across the Apennines since 15 \pm 3 ka (0.4-3.1mm yr^{-1}) occur in the southern Apennines and central Apennines where values for finite extensional strains that have developed since 2-3Ma are highest (2-7km cumulative throw), and where mean topography from SRTM data (Shuttle Radar Topography Mission) is > 600m; the intervening area of Molise-North Campania with < 600m topography has extension-rates < 0.4mm yr^{-1} and lower values for finite extensional strains (< 2km cumulative throw). These two areas with high upper-crustal extension-rates overlie mantle that has relatively-long spatially-interpolated SKS delay times (1.2-1.8 seconds) and relatively-high free-air gravity values of 140-160 mGals; the intervening area of lower extension-rates has relatively-low spatially-interpolated SKS delay times of 0.8-1.2 seconds and relatively-low free-air gravity values of 120 mGals. These correlations suggest that at the regional length-scale, a sub-crustal process, that is, dynamic support of the topography by mantle upwelling, controls the present-day upper-crustal strain-rate field in the Apennines and the geography of seismic hazard in the region. At a smaller length-scale, in order to investigate the relationship between the throws and 3D orientation of breaching faults crossing relay zones, kinematic data, throw-rates and total throws have been measured for an active normal fault in the Italian Apennines that displays a relay zone at its centre. The c.0.8km long breaching fault, investigated in detail, dips at 67^o\pm5^o and strikes obliquely to c.2-3km long faults outside the relay zone which dip at 61^o\pm5^o.Total throws of pre-rift limestone define a throw profile with a double maximum (370\pm50 m; 360\pm50 m) separated by an area of lower throw (100\pm50 m) where the breaching fault is growing. Throw-rates implied by offsets across bedrock scarps of Late Pleistocene-Holocene landforms (15 \pm 3 ka) are higher across the breaching fault (0.67\pm0.13mm yr^{-1}) than for locations of throw maxima on the neighbouring faults (0.38\pm0.07mm yr^{-1}; 0.55\pm0.11mm yr^{-1}). The deficit in total throw will be removed in 0.68-1.0 Myrs if these deformation rates continue. To investigate why the highest throw-rates occur in the location with lowest total throw, horizontal strain-rate tensors were calculated in 1km \times 2km boxes. It is shown that the oblique strike and relatively-high dip of the breaching fault mean that it must have a relatively-high throw-rate in order for it to have a horizontal strain-rate concomitant with its position at the centre of the overall fault. It is shown that whether throw minima at locations of fault linkage are preserved during progressive fault slip depends on the 3D orientation of the breaching fault. The above is used to discuss the longevity of throw deficits and multiple throw maxima along faults in relation to seismic hazard and landscape evolution. Overall, this thesis shows that calculation of horizontal strain-rates using the method developed herein, supported by collection of field data from active faults, can provide new insights into regional mechanisms of continental extension, seismic hazard, the seismic cycle, and fault growth; it provides a test of the hypothesis that earthquake recurrence is spatially random, providing evidence that instead, earthquake recurrence shows a spatial pattern that is controlled by fault evolution and sub-crustal processes

    A complementary compact laser based neutron source

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    Several experiments of neutron generation using high intensity laser sources, with a power exceeding 10^19W/cm^2 via TNSA (Target Normal Sheath Acceleration) or other similar methods, have been performed in the past years in different laboratories. However, so far there is no one running neutron source based on such a technology. In the framework of the Conceptual Report Design of a new accelerator in the Eupraxia project we are studying the possibility to have a laser-based neutron source, not only by TNSA but also from self-injection schemes. We focus our attention on the applications in cultural heritage studies as well also on the complementary role that such a source can have in the framework of large facilities devoted to radiation production.Comment: 4 pages, two figures, 3rd European Advanced Accelerators Concept
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