4,646 research outputs found
Supporting ethnographic studies of ubiquitous computing in the wild
Ethnography has become a staple feature of IT research over the last twenty years, shaping our understanding of the social character of computing systems and informing their design in a wide variety of settings. The emergence of ubiquitous computing raises new challenges for ethnography however, distributing interaction across a burgeoning array of small, mobile devices and online environments which exploit invisible sensing systems. Understanding interaction requires ethnographers to reconcile interactions that are, for example, distributed across devices on the street with online interactions in order to assemble coherent understandings of the social character and purchase of ubiquitous computing systems. We draw upon four recent studies to show how ethnographers are replaying system recordings of interaction alongside existing resources such as video recordings to do this and identify key challenges that need to be met to support ethnographic study of ubiquitous computing in the wild
Solar energy conversion
If solar energy is to become a practical alternative to fossil fuels, we must have efficient ways to convert photons into electricity, fuel, and heat. The need for better conversion technologies is a driving force behind many recent developments in biology, materials, and especially nanoscience
Problematising international placements as a site of intercultural learning
This paper theorises some of the learning outcomes of a three-year project concerning student learning in international social work placements in Malaysia. The problematic issue of promoting cultural and intercultural competence through such placements is examined, where overlapping hegemonies are discussed in terms of isomorphism of social work models, that of the nation state, together with those relating to professional values and knowledge, and the tyrannies of received ideas. A critical discussion of cultural competence as the rationale for international placements is discussed in terms of the development of the graduating social worker as a self-reflexive practitioner. The development of sustainable international partnerships able to support student placement and the issue of non-symmetrical reciprocation, typical of wide socio-economic differentials across global regions, is additionally discussed
The Effect of Large Amplitude Fluctuations in the Ginzburg-Landau Phase Transition
The lattice Ginzburg-Landau model in d=3 and d=2 is simulated, for different
values of the coherence length in units of the lattice spacing , using
a Monte Carlo method. The energy, specific heat, vortex density , helicity
modulus and mean square amplitude are measured to map the phase
diagram on the plane . When amplitude fluctuations, controlled by the
parameter , become large () a proliferation of vortex
excitations occurs changing the phase transition from continuous to first
order.Comment: 4 pages, 5 postscript (eps) figure
Amalgamated reference data for size-adjusted bone densitometry measurements in 3598 children and young adults – the ALPHABET study
The increasing use of dual energy X-ray absorptiometry (DXA) in children has led to the need for robust reference data for interpretation of scans in daily clinical practice. Such data need to be representative of the population being studied and be ‘future-proofed’ to software and hardware upgrades. The aim was to combine all available paediatric DXA reference data from seven UK centres to create reference curves adjusted for age, sex, ethnicity and body size to enable clinical application, using in-vivo cross calibration and making data back- and forward- compatible.
Seven UK sites collected data on GE-Lunar or Hologic Scanners between 1996 and 2012. Males and females aged 4 to 20 years were recruited (n = 3598). The split by ethnic group was: White Caucasian 2887; South Asian 385; Black Afro-Caribbean 286; mixed heritage 40. Scans of the total body and lumbar spine (L1-L4) were obtained. The European Spine Phantom was used to cross-calibrate the 7 centres and 11 scanners. Reference curves were produced for L1-L4 bone mineral apparent density (BMAD) and total body less head (TBLH) and L1-L4 areal bone mineral density (aBMD) for GE Lunar Prodigy and iDXA (sex-and ethnic-specific) and for Hologic (sex-specific). Regression equations for TBLH BMC were produced using stepwise linear regression. Scans of 100 children were randomly selected to test backwards and forwards compatibility of software versions, up to version 15.0 for GE Lunar, and Apex 4.0 for Hologic.
For the first time, sex and ethnic- specific reference curves for lumbar spine BMAD, aBMD and TBLH aBMD are provided for both GE-Lunar and Hologic scanners. These curves will facilitate interpretation of DXA data in children using methods recommended in ISCD guidelines. The databases have been created to allow future updates and analysis when more definitive evidence for the best method of fracture prediction in children is agreed
Searching for music: understanding the discovery, acquisition, processing and organization of music in a domestic setting for design
This series of studies make it clear that a wide range of both physical and digital resources are involved in domestic music consumption. The selection of digital resources is particularly evident, and it can be observed that domestic music consumption is a fragmented business, taking advantage of many different "channels'' for getting, using and preparing music. While there are not a series of common channels, each home displayed a variety of methods in respect to using metadata in multiple different modalities: regardless, the activities involved in getting, using and preparing music cohere through a noticeable, emergent set of workflows. We find that not only does metadata support searching, as one might expect, but also it pervades all parts of the workflow and is used in real-time as a reflexive artifact and in terms of its future perceived/prescribed use. The findings of the research raise a series of possibilities and issues that form the basis for understanding and designing for metadata use
Carbon Stars and other Luminous Stellar Populations in M33
The M33 galaxy is a nearby, relatively metal-poor, late-type spiral. Its
proximity and almost face-on inclination means that it projects over a large
area on the sky, making it an ideal candidate for wide-field CCD mosaic
imaging. Photometry was obtained for more than 10^6 stars covering a 74' x 56'
field centered on M33. Main sequence (MS), supergiant branch (SGB), red giant
branch (RGB) and asymptotic giant branch (AGB) populations are identified and
classified based on broad-band V and I photometry. Narrow-band filters are used
to measure spectral features allowing the AGB population to be further divided
into C and M-star types. The galactic structure of M33 is examined using star
counts, colour-colour and colour-magnitude selected stellar populations. We use
the C to M-star ratio to investigate the metallicity gradient in the disk of
M33. The C/M-star ratio is found to increase and then flatten with increasing
galactocentric radius in agreement with viscous disk formation models. The
C-star luminosity function is found to be similar to M31 and the SMC,
suggesting that C-stars should be useful distance indicators. The ``spectacular
arcs of carbon stars'' in M33 postulated recently by Block et al. (2004) are
found in our work to be simply an extension of M33's disk.Comment: 20 pages, 20 figures. Accepted for publication in The Astronomical
Journa
Inhomogeneity of the intrinsic magnetic field in superconducting YBa2Cu3OX compounds as revealed by rare-earth EPR-probe
X-band electron paramagnetic resonance on doped Er3+ and Yb3+ ions in
Y0.99(Yb,Er)0.01Ba2Cu3OX compounds with different oxygen contents in the wide
temperature range (4-120)K have been made. In the superconducting species, the
strong dependencies of the linewidth and resonance line position from the sweep
direction of the applied magnetic field are revealed at the temperatures
significantly below TC. The possible origins of the observed hysteresis are
analyzed. Applicability of the presented EPR approach to extract information
about the dynamics of the flux-line lattice and critical state parameters
(critical current density, magnetic penetration depth, and characteristic
spatial scale of the inhomogeneity) is discussedComment: 17 pages, 5 Figures. Renewed versio
Zooming into the coexisting regime of ferromagnetism and superconductivity in ErRh4B4 single crystals
High resolution measurements of the dynamic magnetic susceptibility are
reported for ferromagnetic re-entrant superconductor, ErRhB.
Detailed investigation of the coexisting regime reveals unusual
temperature-asymmetric and magnetically anisotropic behavior. The
superconducting phase appears via a series of discontinuous steps upon warming
from the ferromagnetic normal phase, whereas the ferromagnetic phase develops
via a gradual transition. A model based on local field inhomogeneity is
proposed to explain the observations
- …
