354 research outputs found
Social technologies for online learning: theoretical and contextual issues
Three exemplars are presented of social technologies deployed in educational contexts: wikis; a photo-sharing environment; and a social bookmarking tool. Students were found to engage with the technologies selectively, sometimes rejecting them, in the light of their prior conceptions of education. Some students (a minority in all the studies) were unsympathetic to the educational philosophy underpinning the technologyâs adoption. The paper demonstrates, through an examination of in-context use, the importance of socio-cultural factors in relation to education, and the non-deterministic nature of educational technology. The academic study of technology has increasingly called into question the deterministic views which are so pervasive in popular discourse and among policy makers. Instead, socio-cultural factors play a crucial role in shaping and defining technology and educational technology is no exception, as the examples in the paper show. The paper concludes by drawing out some implications of the examples for the use of social technologies in education
What about if buildings respond to my mood?
This work analyzes the possibilities of interaction between the built environment and its users, focused on the responsiveness of the first to the emotions of the latter. Transforming the built environment according to the mood, feelings, and emotions of users, moment by moment, is discussed and analyzed. The main goal of this research is to define a responsive model by which the built environment can respond in a personalized way to the usersâ emotions. For such, computational technical issues, building construction elements and usersâ interaction are identified and analyzed. Case studies where occurs an interaction between the physical space and users are presented. We define a model for an architecture that is responsive to the userâs emotions assuming the individual at one end and the space at the other. The interaction between both ends takes place according to intermediate steps: the collection of data, the recognition of emotion, and the execution of the action that responds to the detected emotion. As this work focuses on an innovative and disruptive aspect of the built environment, the recognition of the new difficulties and related ethical issues are discussed.info:eu-repo/semantics/acceptedVersio
The COBE Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background: IV. Cosmological Implications
In this paper we examine the cosmological constraints of the recent DIRBE and
FIRAS detection of the extragalactic background light between 125-5000 microns
on the metal and star formation histories of the universe.Comment: 38 pages and 9 figures. Accepted for publications in The
Astrophysical Journa
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Five Ws and an H: Digital Challenges in Newspaper Newsrooms and Boardrooms
It is no news to anyone involved with the media, from the newsroom to the boardroom to the classroom, that journalism is at a crossroads as an occupation, a business, a content form, and a public good. This is perhaps particularly true of journalism in the traditional news medium of record, the newspaper, where enormous uncertainty surrounds virtually every facet of the enterprise as it adjusts to being part of a digital network. This essay uses a framework familiar to journalists and journalism educators -- the traditional âfive Ws and an Hâ of who, what, when, where, why, and how -- to address some of the significant issues facing corporate and newsroom managers, as well as journalists themselves
CMB Anisotropies: Total Angular Momentum Method
A total angular momentum representation simplifies the radiation transport
problem for temperature and polarization anisotropy in the CMB. Scattering
terms couple only the quadrupole moments of the distributions and each moment
corresponds directly to the observable angular pattern on the sky. We develop
and employ these techniques to study the general properties of anisotropy
generation from scalar, vector and tensor perturbations to the metric and the
matter, both in the cosmological fluids and from any seed perturbations (e.g.
defects) that may be present. The simpler, more transparent form and derivation
of the Boltzmann equations brings out the geometric and model-independent
aspects of temperature and polarization anisotropy formation. Large angle
scalar polarization provides a robust means to distinguish between isocurvature
and adiabatic models for structure formation in principle. Vector modes have
the unique property that the CMB polarization is dominated by magnetic type
parity at small angles (a factor of 6 in power compared with 0 for the scalars
and 8/13 for the tensors) and hence potentially distinguishable independent of
the model for the seed. The tensor modes produce a different sign from the
scalars and vectors for the temperature-polarization correlations at large
angles. We explore conditions under which one perturbation type may dominate
over the others including a detailed treatment of the photon-baryon fluid
before recombination.Comment: 32 pg., 10 figs., RevTeX, minor changes reflect published version,
minor typos corrected, also available at http://www.sns.ias.edu/~wh
Breakdown of the adiabatic limit in low dimensional gapless systems
It is generally believed that a generic system can be reversibly transformed
from one state into another by sufficiently slow change of parameters. A
standard argument favoring this assertion is based on a possibility to expand
the energy or the entropy of the system into the Taylor series in the ramp
speed. Here we show that this argumentation is only valid in high enough
dimensions and can break down in low-dimensional gapless systems. We identify
three generic regimes of a system response to a slow ramp: (A) mean-field, (B)
non-analytic, and (C) non-adiabatic. In the last regime the limits of the ramp
speed going to zero and the system size going to infinity do not commute and
the adiabatic process does not exist in the thermodynamic limit. We support our
results by numerical simulations. Our findings can be relevant to
condensed-matter, atomic physics, quantum computing, quantum optics, cosmology
and others.Comment: 11 pages, 5 figures, to appear in Nature Physics (originally
submitted version
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Coextensive space: virtual reality and the developing relationship between the body, the digital and physical space
Virtual Reality (VR) has traditionally required external sensors placed around a designated play space. In contrast, more recent wired and wireless systems, such as the Oculus Rift S (released in March 2019) and the Oculus Quest (released in May 2019) use cameras located on the outside of these devices to monitor their physical position. Users can now mark out a physical space that is then digitally tracked within their display. Once a play space has been established, users are alerted if they come close to breaching this boundary by the visual inclusion of a grid. Should this threshold be breached, the headset display shifts to an image of the surrounding concrete environment. We contend that physical space is increasingly being incorporated into the digital space of VR in a manner that meaningfully differs from older systems. We build our argument in the following way. First, the article explores how theories surrounding VR have implicated only a limited relationship with physical space. Second, the article introduces the concept of coextensive space as a way of understanding the developing relationship between the physical, digital and concrete reality enacted by current VR systems
Morphological Evolution of Galaxies
We simulate the growth of large-scale structure in the universe using a
N-body code. By combining these simulations with a Monte-Carlo method, we
generate galaxy distributions at present that reproduces the observed
morphology-density relation, with most ellipticals concentrated in the densest
regions. By "tying" each galaxy to its nearest particle, we trace the
trajectory of that galaxy back in time. This enables us to reconstruct the
distribution of galaxies at high redshift, and the trajectory of each galaxy
from its formation epoch to the present. Our goal is to determine whether the
morphological type of galaxies is primarily determined by the initial
conditions in which these galaxies form, or by evolutionary processes occurring
later. We compare the environment in which galaxies are at the epoch of galaxy
formation (z=3) and at the present. Making the null hypothesis that
morphological types do not evolve, we compare the galaxies that form in low
density environments but end up later in high density environments to the ones
that form also in low density environment but remain in low density
environment. The first group contains a larger proportion of E and S0 galaxies
than the second group. We assume that the galaxy formation process cannot
distinguish a low density environment that will always remain low density from
one that will eventually become high density. Hence, these results force us to
discard the null hypothesis of no morphological evolution. Our study suggests
that 75% of the E and S0 galaxies observed at present formed as such, while the
remaining 25% formed as spirals, and underwent morphological evolution. We
conclude that most galaxies did not undergo morphological evolution, but a
non-negligible fraction did.Comment: 29 pages (AAS latex) + 7 figures (postscript) combined in one gzip-ed
tar file. Submitted to The Astrophysical Journal (Dec 1996
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