8,190 research outputs found
Digital curation and the cloud
Digital curation involves a wide range of activities, many of which could benefit from cloud
deployment to a greater or lesser extent. These range from infrequent, resource-intensive tasks
which benefit from the ability to rapidly provision resources to day-to-day collaborative activities
which can be facilitated by networked cloud services. Associated benefits are offset by risks
such as loss of data or service level, legal and governance incompatibilities and transfer
bottlenecks. There is considerable variability across both risks and benefits according to the
service and deployment models being adopted and the context in which activities are
performed. Some risks, such as legal liabilities, are mitigated by the use of alternative, e.g.,
private cloud models, but this is typically at the expense of benefits such as resource elasticity
and economies of scale. Infrastructure as a Service model may provide a basis on which more
specialised software services may be provided.
There is considerable work to be done in helping institutions understand the cloud and its
associated costs, risks and benefits, and how these compare to their current working methods,
in order that the most beneficial uses of cloud technologies may be identified. Specific
proposals, echoing recent work coordinated by EPSRC and JISC are the development of
advisory, costing and brokering services to facilitate appropriate cloud deployments, the
exploration of opportunities for certifying or accrediting cloud preservation providers, and
the targeted publicity of outputs from pilot studies to the full range of stakeholders within the
curation lifecycle, including data creators and owners, repositories, institutional IT support
professionals and senior manager
Quantum Hall Effect on the Hyperbolic Plane
In this paper, we study both the continuous model and the discrete model of
the Quantum Hall Effect (QHE) on the hyperbolic plane. The Hall conductivity is
identified as a geometric invariant associated to an imprimitivity algebra of
observables. We define a twisted analogue of the Kasparov map, which enables us
to use the pairing between -theory and cyclic cohomology theory, to identify
this geometric invariant with a topological index, thereby proving the
integrality of the Hall conductivity in this case.Comment: AMS-LaTeX, 28 page
Time delay and integration detectors using charge transfer devices
An imaging system comprises a multi-channel matrix array of CCD devices wherein a number of sensor cells (pixels) in each channel are subdivided and operated in discrete intercoupled groups of subarrays with a readout CCD shift register terminating each end of the channels. Clock voltages, applied to the subarrays, selectively cause charge signal flow in each subarray in either direction independent of the other subarrays. By selective application of four phase clock voltages, either one, two or all three of the sections subarray sections cause charge signal flow in one direction, while the remainder cause charge signal flow in the opposite direction. This creates a form of selective electronic exposure control which provides an effective variable time delay and integration of three, six or nine sensor cells or integration stages. The device is constructed on a semiconductor sustrate with a buried channel and is adapted for front surface imaging through transparent doped tin oxide gates
Infrared spectroscopy of hole doped ABA-stacked trilayer graphene
Using infrared spectroscopy, we investigate bottom gated ABA-stacked trilayer
graphene subject to an additional environment-induced p-type doping. We find
that the Slonczewski-Weiss-McClure tight-binding model and the Kubo formula
reproduce the gate voltage-modulated reflectivity spectra very accurately. This
allows us to determine the charge densities and the potentials of the
{\pi}-band electrons on all graphene layers separately and to extract the
interlayer permittivity due to higher energy bands.Comment: 6 pages, 6 figures Corrected sign of fig 3 and visibilty of fig
From clean to diffusive mesoscopic systems: A semiclassical approach to the magnetic susceptibility
We study disorder-induced spectral correlations and their effect on the
magnetic susceptibility of mesoscopic quantum systems in the non-diffusive
regime. By combining a diagrammatic perturbative approach with semiclassical
techniques we perform impurity averaging for non-translational invariant
systems. This allows us to study the crossover from clean to diffusive systems.
As an application we consider the susceptibility of non-interacting electrons
in a ballistic microstructure in the presence of weak disorder. We present
numerical results for a square billiard and approximate analytic results for
generic chaotic geometries. We show that for the elastic mean free path
larger than the system size, there are two distinct regimes of behaviour
depending on the relative magnitudes of and an inelastic scattering
length.Comment: 7 pages, Latex-type, EuroMacr, 4 Postscript figures, to appear in
Europhys. Lett. 199
Gate-tunable bandgap in bilayer graphene
The tight-binding model of bilayer graphene is used to find the gap between
the conduction and valence bands, as a function of both the gate voltage and as
the doping by donors or acceptors. The total Hartree energy is minimized and
the equation for the gap is obtained. This equation for the ratio of the gap to
the chemical potential is determined only by the screening constant. Thus the
gap is strictly proportional to the gate voltage or the carrier concentration
in the absence of donors or acceptors. In the opposite case, where the donors
or acceptors are present, the gap demonstrates the asymmetrical behavior on the
electron and hole sides of the gate bias. A comparison with experimental data
obtained by Kuzmenko et al demonstrates the good agreement.Comment: 6 pages, 5 figure
Land Settlement Act Amendment Act, 1957, No. 26
In recent years, there has been a widespread interest in the economic development role played by 'Bohemian' occupations and the 'creative class'. It is believed that creative people and occupations generate external effects which foster economic growth. However, the degree to which these externalities affect production and consumption is as yet not clear. As part of this debate, we investigate the ability of creative individuals to internalize the rents accruing from creative occupations in comparison with other types of activities. In order to do this, the paper analyzes the employment opportunities and wages earned by graduates in artistic occupations (Bohemians) and compares them with those of non-Bohemians. Using a uniquely longitudinal dataset of UK university graduates, we examine these issues using a Mincer-type framework, both in the short and in medium term after graduation. Our findings suggest that there is a persistent gap between Bohemian and non-Bohemians in terms of both the wages earned and employment status. This observation sharpens the need to better understanding the nature and extent of the externalities associated with the creative class which remains an unresolved issue
A glimpse into the differential topology and geometry of optimal transport
This note exposes the differential topology and geometry underlying some of
the basic phenomena of optimal transportation. It surveys basic questions
concerning Monge maps and Kantorovich measures: existence and regularity of the
former, uniqueness of the latter, and estimates for the dimension of its
support, as well as the associated linear programming duality. It shows the
answers to these questions concern the differential geometry and topology of
the chosen transportation cost. It also establishes new connections --- some
heuristic and others rigorous --- based on the properties of the
cross-difference of this cost, and its Taylor expansion at the diagonal.Comment: 27 page
Effectiveness of guided self-help in decreasing expressed emotion in family caregivers of people diagnosed with depression in Thailand: a randomised controlled trial
Background: High expressed emotion (EE) can extend the duration of illness and precipitate relapse; however, little evidence-based information is available to assist family caregivers of individuals with depression. In the present exploratory study, we examined the effectiveness of a cognitive behaviour therapy (CBT) based guided self-help (GSH) manual in decreasing EE in caregivers of people with depression, in Thailand.
Method: A parallel group randomised controlled trial was conducted, following CONSORT guidelines, with 54 caregivers who were allocated equally to GSH or control group (standard outpatient department support). In addition, both groups were contacted weekly by telephone. EE was assessed, using the Family Questionnaire (FQ), at baseline, post-test (Week 8) and follow-up (Week 12).
Results: FQ scores at baseline indicated that both groups had similar, though moderately high level of EE. However, between baseline and post-test EE scores decreased markedly in the intervention group, but in contrast, they increased slightly in the control group. Between post-test and follow-up, little change took place in the EE scores of either group. Overall, the intervention group recipients of GSH showed a significant decrease in EE whereas the control group recipients of standard outpatient department support reported a slight increase in EE.
Conclusion: These findings provide preliminary evidence that GSH is beneficial in reducing EE in caregivers, which is advantageous to family members with depression and caregivers. The approach may be used as an adjunct to the limited outpatient department support given to caregivers by mental health professionals and, perhaps, to caregivers who do not attend these departments
- …