15,424 research outputs found
The importance of real-world experience in student learning
A core module for the computer science and computing degree courses at the University of North London provided a vehicle for developing an innovative approach in teaching and learning. It served as a means of bridging the gap between real-world business information systems (BIS) development practice and that which is normally simulated in academia. We also show how students can be encouraged to be proactive in creating their own real-world learning experience within an academic environment
Outsourcing network management
The paper analyses the current situation in
outsourcing of IT and network management
through the literature review and examples in
industry. We have focused on trends, benefits
and risks in outsourcing network management
and made proposals to address the problems
through a carefully managed network
outsourcing relationship. The available statistics
and the the survey of six UK companies has
revealed that the upfront negotiation of service
level agreements should be one of the most
important aspects of conducting the outsourcing
of network management
Band structures of rare gas solids within the GW approximation
Band structures for solid rare gases (Ne, Ar) have been calculated using the
GW approximation. All electron and pseudopotential ab initio calculations were
performed using Gaussian orbital basis sets and the dependence of particle-hole
gaps and electron affinities on basis set and treatment of core electrons is
investigated. All electron GW calculations have a smaller particle-hole gap
than pseudopotential GW calculations by up to 0.2 eV. Quasiparticle electron
and hole excitation energies, valence band widths and electron affinities are
generally in very good agreement with those derived from optical absorption and
photoemission measurements.Comment: 7 pages 1 figur
Adapted digital music players for individuals with severe impairments
This is the peer reviewed version of the following article: Saunders, M. D., Questad, K. A., Cullinan, T. B., & Saunders, R. R. (2011). Adapted Digital Music Players for Individuals with Severe Impairments. Behavioral InterventionsâŻ: Theory & Practice in Residential & Community-Based Clinical Programs, 26(2), 10.1002/bin.327. http://doi.org/10.1002/bin.327, which has been published in final form at doi.org/10.1002/bin.327. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingPortable music production devices, such as radios, cassette players and MP3 players have characteristics that make them less than ideal for teaching the cause-and-effect relationships that would enable children and adults with severe impairments to control them independently and appropriately. Even when adapted for control with adaptive switches, the relationship between switch closure and on-off operation results in contingency characteristics that can inhibit learning. Some solutions to these problems are described, and for those individuals who can learn with complex contingencies, some promising products are reviewed
Electronic structure of the molecule based magnet Cu PM(NO3)2 (H2O)2
We present density functional calculations on the molecule based S=1/2
antiferromagnetic chain compound Cu PM(NO3)2 (H2O)2; PM = pyrimidine. The
properties of the ferro- and antiferromagnetic state are investigated at the
level of the local density approximation and with the hybrid functional B3LYP.
Spin density maps illustrate the exchange path via the pyrimidine molecule
which mediates the magnetism in the one-dimensional chain. The computed
exchange coupling is antiferromagnetic and in reasonable agreement with the
experiment. It is suggested that the antiferromagnetic coupling is due to the
possibility of stronger delocalization of the charges on the nitrogen atoms,
compared to the ferromagnetic case. In addition, computed isotropic and
anisotropic hyperfine interaction parameters are compared with recent NMR
experiments
Bayes-X: a Bayesian inference tool for the analysis of X-ray observations of galaxy clusters
We present the first public release of our Bayesian inference tool, Bayes-X,
for the analysis of X-ray observations of galaxy clusters. We illustrate the
use of Bayes-X by analysing a set of four simulated clusters at z=0.2-0.9 as
they would be observed by a Chandra-like X-ray observatory. In both the
simulations and the analysis pipeline we assume that the dark matter density
follows a spherically-symmetric Navarro, Frenk and White (NFW) profile and that
the gas pressure is described by a generalised NFW (GNFW) profile. We then
perform four sets of analyses. By numerically exploring the joint probability
distribution of the cluster parameters given simulated Chandra-like data, we
show that the model and analysis technique can robustly return the simulated
cluster input quantities, constrain the cluster physical parameters and reveal
the degeneracies among the model parameters and cluster physical parameters. We
then analyse Chandra data on the nearby cluster, A262, and derive the cluster
physical profiles. To illustrate the performance of the Bayesian model
selection, we also carried out analyses assuming an Einasto profile for the
matter density and calculated the Bayes factor. The results of the model
selection analyses for the simulated data favour the NFW model as expected.
However, we find that the Einasto profile is preferred in the analysis of A262.
The Bayes-X software, which is implemented in Fortran 90, is available at
http://www.mrao.cam.ac.uk/facilities/software/bayesx/.Comment: 22 pages, 11 figure
When it Pays to Rush: Interpreting Morphogen Gradients Prior to Steady-State
During development, morphogen gradients precisely determine the position of
gene expression boundaries despite the inevitable presence of fluctuations.
Recent experiments suggest that some morphogen gradients may be interpreted
prior to reaching steady-state. Theoretical work has predicted that such
systems will be more robust to embryo-to-embryo fluctuations. By analysing two
experimentally motivated models of morphogen gradient formation, we investigate
the positional precision of gene expression boundaries determined by
pre-steady-state morphogen gradients in the presence of embryo-to-embryo
fluctuations, internal biochemical noise and variations in the timing of
morphogen measurement. Morphogens that are direct transcription factors are
found to be particularly sensitive to internal noise when interpreted prior to
steady-state, disadvantaging early measurement, even in the presence of large
embryo-to-embryo fluctuations. Morphogens interpreted by cell-surface receptors
can be measured prior to steady-state without significant decrease in
positional precision provided fluctuations in the timing of measurement are
small. Applying our results to experiment, we predict that Bicoid, a
transcription factor morphogen in Drosophila, is unlikely to be interpreted
prior to reaching steady-state. We also predict that Activin in Xenopus and
Nodal in zebrafish, morphogens interpreted by cell-surface receptors, can be
decoded in pre-steady-state.Comment: 18 pages, 3 figure
Optical coherence tomography- a non-invasive technique applied to conservation of paintings
It is current practice to take tiny samples from a painting to mount and examine in cross-section under a microscope. However, since conservation practice and ethics limit sampling to a minimum and to areas along cracks and edges of paintings, which are often unrepresentative of the whole painting, results from such analyses cannot be taken as representative of a painting as a whole. Recently in a preliminary study, we have demonstrated that near-infrared Optical Coherence Tomography (OCT) can be used directly on paintings to examine the cross-section of paint and varnish layers without contact and the need to take samples. OCT is an optical interferometric technique developed for in vivo imaging of the eye and biological tissues; it is essentially a scanning Michelsonâs interferometer with a âbroadbandâ source that has the spatial coherence of a laser. The low temporal coherence and high spatial concentration of the source are the keys to high depth resolution and high sensitivity 3D imaging. The technique is non-invasive and noncontact with a typical working distance of 2 cm. This non-invasive technique enables cross-sections to be examined anywhere on a painting. In this paper, we will report new results on applying near-infrared en-face OCT to paintings conservation and extend the application to the examination of underdrawings, drying processes, and quantitative measurements of optical properties of paint and varnish layers
Influence of a Corpus Luteum Tissue Extract on Rabbit Ovarian Mesothelial Cells
This study investigates rabbit ovarian mesothelial (OM) cells exposed in vitro to a crude corpus luteum extract (CLE; 60 Όg/ml). The growth of OM cells was evaluated by measuring the change in cell number (mean % ± standard error of mean, SEM), the number of cell population doublings (CPD ± SEM), and the cell population doubling time in hours (CPDT ± SEM) after 7.5 days of culture in a serum-poor medium. Quantitative estimates of surface morphology changes were obtained by analyzing the total number (mean no. ± SEM), density (mean no./100 Ό.m2 ± SEM), and length-to-diameter ratio (mean L/D ± SEM) of microvilli. OM cells in control medium formed loosely cohesive monolayers, and grew 152.53 ± 11.01% with a CPD of 0.59 ± 0.08 and a CPDT of 117.29 ± 6.43 hours. The exposed surface area of these cells was over 8,000 Ό.m2 and was covered in its epinuclear region by long and slender microvilli with a L/D of 6.01 ± 0.29. The total number of microvilli in each control cell was 1977.52 ± 120.49 with a density of 0.58 ± 0.03/100 Ό.m2 in the epinuclear region and of 0.05 ± 0.003/150 Ό.m2 in the remaining surface area (5,161.62 ± 354.43 Ό.m2). In contrast, CLE-rich cells cultures grew 329.57 ± 16.65%, with a CPD of 1.71 ± 0.07 and a CPDT of 53.43 + 2.93 hours. These cells formed confluent monolayers of smaller (2104.86 ± 103.71 Ό.m2), tightly juxtaposed epithelioid cells with a microvillar density of 0.70 ± 0.03/100 Ό.m2 in over 78% of their surface. These data support the existence of an intra-ovarian factor capable of enhancing growth and differentiation of OM cells
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