1,833 research outputs found
Multi-User Interactive TV: the Next Step in Personalization
In the past few years there has been an increasing trend towards personalization in the TV world. IMS-based IPTV is a good example of a highly personalized IPTV architecture, featuring an advanced identity management subsystem. This article studies a next step in the personalization of the television experience: concurrent use of TV services that are supported by the IMSbased IPTV system. That is, multiple users using the same television set at the same or at different times, where each user as personalized interaction with the service and content. Our analysis of IMS-based IPTV use cases shows that current architectures were not designed with concurrent use in mind. However, we demonstrate that the combination of concurrent use and personalized TV services can yield interesting and viable use cases in the areas of interactive game shows, personalized electronic program guides and channel lists, and other. Finally, an analysis of the IMS-based IPTV system and architecture shows that it has all the ingredients to implement these new concurrent TV use cases, and that the main challenges will be in the area of usability. The article concludes that personalization and concurrency are not contradictory for television services, neither from a use case perspective, nor technologically. In particular, the IMS-based IPTV system is able to facilitate an enhanced and personalized experience to concurrent TV users
Proton radiography to improve proton radiotherapy: Simulation study at different proton beam energies
To improve the quality of cancer treatment with protons, a translation of
X-ray Computed Tomography (CT) images into a map of the proton stopping powers
needs to be more accurate. Proton stopping powers determined from CT images
have systematic uncertainties in the calculated proton range in a patient of
typically 3-4\% and even up to 10\% in region containing
bone~\cite{USchneider1995,USchneider1996,WSchneider2000,GCirrone2007,HPaganetti2012,TPlautz2014,GLandry2013,JSchuemann2014}.
As a consequence, part of a tumor may receive no dose, or a very high dose can
be delivered in healthy ti\-ssues and organs at risks~(e.g. brain
stem)~\cite{ACKnopf2013}. A transmission radiograph of high-energy protons
measuring proton stopping powers directly will allow to reduce these
uncertainties, and thus improve the quality of treatment.
The best way to obtain a sufficiently accurate radiograph is by tracking
individual protons traversing the phantom
(patient)~\cite{GCirrone2007,TPlautz2014,VSipala2013}. In our simulations we
have used an ideal position sensitive detectors measuring a single proton
before and after a phantom, while the residual energy of a proton was detected
by a BaF crystal. To obtain transmission radiographs, diffe\-rent phantom
materials have been irradiated with a 3x3~cm scattered proton beam, with
various beam energies. The simulations were done using the Geant4 simulation
package~\cite{SAgostinelli2003}.
In this study we focus on the simulations of the energy loss radiographs for
various proton beam energies that are clinically available in proton
radiotherapy.Comment: 6 pages, 6 figures, Presented at Jagiellonian Symposium on
Fundamental and Applied Subatomic Physics, 7-12 June, 2015, Krak\'ow, Polan
Phase toxicity of dodecane on the microalga Dunaliella salina
In the so-called milking process of Dunaliella salina carotenoids are extracted and simultaneously produced by the culture, whilst the biomass concentration remains constant. Different theories exist about the extraction mechanisms although none have been proven yet. In this research, direct contact between dodecane and cells during the extraction process was studied microscopically and effects of direct contact were determined during in situ extraction experiments. Our results showed that water– solvent interphase contact resulted in cell death. This cell death and consequent cell rupture resulted in the release and concomitant extraction of the carotenoids. Furthermore, it has been suggested to add a small amount of dichloromethane to the biocompatible dodecane to create an organic phase with more extraction capacity. Our results showed that the addition of dichloromethane resulted in increased cell death and consequently the extraction rate increased. The improved solubility of carotenoids in an organic phase with dichloromethane did not significantly increase the extraction rate
When long-distance relationships don't work out: Representational distance and satisfaction with democracy in Europe
Magnetoconvection and dynamo coefficients III: alpha-effect and magnetic pumping in the rapid rotation regime
Aims. The alpha- and gamma-effects, which are responsible for the generation
and turbulent pumping of large scale magnetic fields, respectively, due to
passive advection by convection are determined in the rapid rotation regime
corresponding to the deep layers of the solar convection zone.
Methods. A 3D rectangular local model is used for solving the full set of MHD
equations in order to compute the electromotive force (emf), E = ,
generated by the interaction of imposed weak gradient-free magnetic fields and
turbulent convection with varying rotational influence and latitude. By
expanding the emf in terms of the mean magnetic field, E_i = a_ij , all
nine components of a_ij are computed. The diagonal elements of a_ij describe
the alpha-effect, whereas the off-diagonals represent magnetic pumping. The
latter is essentially the advection of magnetic fields by means other than the
underlying large-scale velocity field. Comparisons are made to analytical
expressions of the coefficients derived under the first-order smoothing
approximation (FOSA).
Results. In the rapid rotation regime the latitudinal dependence of the
alpha-components responsible for the generation of the azimuthal and radial
fields does not exhibit a peak at the poles, as is the case for slow rotation,
but at a latitude of about 30 degrees. The magnetic pumping is predominantly
radially down- and latitudinally equatorward as in earlier studies. The
numerical results compare surprisingly well with analytical expressions derived
under first-order smoothing, although the present calculations are expected to
lie near the limits of the validity range of FOSA.Comment: 14 pages, 12 figures, accepted for publication in Astronomy &
Astrophysic
AGOR status report
The operations of the superconducting cyclotron AGOR over the past years will be reviewed. Reliability issues encountered after nearly 25 years of operation and mitigation measures to warrant reliable operation for the coming decade will be discussed. The research performed with AGOR has significantly shifted from fundamental physics to radiation biology and medical radiation physics, both in collaboration with the Groningen Proton Therapy Center, and radiation hardness studies. The radiation biology research will be substantially expanded in the coming years with a new beam line for image guided preclinical research. For this research new dose delivery modalities including scanning, spatial fractionation and very high dose rates are developed. In addition, a new program has been started on the production of exotic nuclei, for which a new superconducting solenoid fragment separator will be developed. For the radiation hardness testing a cocktail beam at 30 MeV/amu with several ion species up to Xe has been developed and is now routinely delivered for experiments. A cocktail at 15 MeV/amu up to Bi is under development
Using usability-tests to improve language match of a web-based system for digital triage in primary care
Measuring therapeutic alliance with children in residential treatment and therapeutic day care:a validation study of the Children’s Alliance Questionnaire
Numerical simulations of the Accretion-Ejection Instability in magnetised accretion disks
The Accretion-Ejection Instability (AEI) described by Tagger & Pellat (1999)
is explored numerically using a global 2d model of the inner region of a
magnetised accretion disk. The disk is initially currentless but threaded by a
vertical magnetic field created by external currents, and frozen in the flow.
In agreement with the theory a spiral instability, similar in many ways to
those observed in self-gravitating disks, develops when the magnetic field is,
within a factor of a few, at equipartition with the disk thermal pressure.
Perturbations in the flow build up currents and create a perturbed magnetic
field within the disk. The present non-linear simulations give good evidence
that such an instability can occur in the inner region of accretion disks, and
generate accretion of gas and vertical magnetic flux toward the central object,
if the equilibrium radial profiles of density and magnetic flux exceed a
critical threshold.Comment: single tar file with GIF figure
Effect of a high-voltage mesh electrode on the volume and surface characteristics of pulsed dielectric barrier discharges
Electrical breakdown in a pulsed asymmetric dielectric barrier discharge between a glass-covered mesh electrode and a grounded metal electrode in the air at atmospheric pressure is investigated. Volume discharge forms between the metal tip and the dielectric surface and spreads over the dielectric surface. Breakdown and discharge behaviors depend on the polarity of the charged electrode covered with glass compared to the metal rod electrode. In the case of the dielectric cathode (covered mesh), volume discharge features a stronger and longer-lasting emission. Volume discharge is weaker with outstretched surface discharge developing on the opposite glass electrode sustained by the embedded mesh when the metal rod functions as a cathode. The development and spatial distribution of the surface discharge depend on the relative polarity of the dielectrics caused by the charge deposition of the preceding discharge and is independent of the polarity of the applied high voltage. The discharge emission is brighter for the metal cathode and dielectric anode than for the metal anode, with a branching discharge developing and spreading in a star-like structure along the embedded grid, while a ring-like structure was observed for the metal anode and dielectric cathode. The duty cycle influences the discharge development and properties through the effects of the gas phase and surface pre-ionization
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