1,917 research outputs found
A Real time network at home
This paper proposes a home network which integrates both real-time and non-real-time capabilities for one coherent, distributed architecture. Such a network is not yet available. Our network will support inexpensive, small appliances as well as more expensive, large appliances. The network is based on a new type of real-time token protocol that uses scheduling to achieve optimal token-routing through the network. Depending on the scheduling algorithm, bandwidth utilisations of 100 percent are possible. Token management, to prevent token-loss or multiple tokens, is essential to support a dynamic, plug-and-play configuration. Small appliances, like sensors, would contain low-cost, embedded processors with limited computing power, which can handle lightweight network protocols. All other operations can be delegated to other appliances that have sufficient resources. This provides a basis for transparency, as it separates controlling and controlled object. Our network will support this. We will show the proposed architecture of such a network and present experiences with and preliminary research of our design
On the formation of coronal cavities
A theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence is presented. It is argued that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due to lack of stable magnetic support against gravity. The existence of a coronal cavity depends on the coronal magnetic field strength; with low strength, the plasma density is not high enough for condensation to occur. Furthermore, we suggest that prominence and cavity material is supplied from the chromospheric level. Whether a coronal cavity and a prominence coexist depends on the magnetic field configuration; a prominence requires stable magnetic support
The Pinhole/Occulter Facility
Scientific objectives and requirements are discussed for solar X-ray observations, coronagraph observations, studies of coronal particle acceleration, and cosmic X-ray observations. Improved sensitivity and resolution can be provided for these studies using the pinhole/occulter facility which consists of a self-deployed boom of 50 m length separating an occulter plane from a detector plane. The X-ray detectors and coronagraphic optics mounted on the detector plane are analogous to the focal plane instrumentation of an ordinary telescope except that they use the occulter only for providing a shadow pattern. The occulter plane is passive and has no electrical interface with the rest of the facility
Association of mid-infrared solar plages with Calcium K line emissions and magnetic structures
Solar mid-IR observations in the 8-15 micrometer band continuum with moderate
angular resolution (18 arcseconds) reveal the presence of bright structures
surrounding sunspots. These plage-like features present good association with
calcium CaII K1v plages and active region magnetograms. We describe a new
optical setup with reflecting mirrors to produce solar images on the focal
plane array of uncooled bolometers of a commercial camera preceded by germanium
optics. First observations of a sunspot on September 11, 2006 show a mid-IR
continuum plage exhibiting spatial distribution closely associated with CaII
K1v line plage and magnetogram structures. The mid-IR continuum bright plage is
about 140 K hotter than the neighboring photospheric regions, consistent with
hot plasma confined by the magnetic spatial structures in and above the active
regionComment: 5 pages, 4 figures. Accepted by PAS
Narrow-line magneto-optical cooling and trapping of strongly magnetic atoms
Laser cooling on weak transitions is a useful technique for reaching
ultracold temperatures in atoms with multiple valence electrons. However, for
strongly magnetic atoms a conventional narrow-line magneto-optical trap (MOT)
is destabilized by competition between optical and magnetic forces. We overcome
this difficulty in Er by developing an unusual narrow-line MOT that balances
optical and magnetic forces using laser light tuned to the blue side of a
narrow (8 kHz) transition. The trap population is spin-polarized with
temperatures reaching below 2 microkelvin. Our results constitute an
alternative method for laser cooling on weak transitions, applicable to
rare-earth-metal and metastable alkaline earth elements.Comment: To appear in Phys. Rev. Lett. 4 pages, 5 figure
Discontinuities without discontinuity: The Weakly-enforced Slip Method
Tectonic faults are commonly modelled as Volterra or Somigliana dislocations
in an elastic medium. Various solution methods exist for this problem. However,
the methods used in practice are often limiting, motivated by reasons of
computational efficiency rather than geophysical accuracy. A typical
geophysical application involves inverse problems for which many different
fault configurations need to be examined, each adding to the computational
load. In practice, this precludes conventional finite-element methods, which
suffer a large computational overhead on account of geometric changes. This
paper presents a new non-conforming finite-element method based on weak
imposition of the displacement discontinuity. The weak imposition of the
discontinuity enables the application of approximation spaces that are
independent of the dislocation geometry, thus enabling optimal reuse of
computational components. Such reuse of computational components renders
finite-element modeling a viable option for inverse problems in geophysical
applications. A detailed analysis of the approximation properties of the new
formulation is provided. The analysis is supported by numerical experiments in
2D and 3D.Comment: Submitted for publication in CMAM
Determinants of parents' experiences with outpatient child and adolescent mental health services
<p>Abstract</p> <p>Background</p> <p>Few studies have investigated how demographic, clinical and organizational characteristics influence parents' experiences with child and adolescent mental health services (CAMHS). The objective of this study was to determine the effects of these characteristics on parents' experiences using data from a large national postal survey.</p> <p>Method</p> <p>A questionnaire was mailed to 17,871 parents or other primary caregivers whose children were attending 1 of the 86 outpatient CAMHS in Norway in 2006. Multiple regression analysis was used to explore the associations between demographic, clinical and organizational characteristics, and three scales of parents' experiences.</p> <p>Results</p> <p>The questionnaire was completed by 7906 parents (46%). Organizational characteristics such as involvement of the parents in treatment and accessibility to the clinic explained most of the variation in all three scales of parents' experiences. Although the effects of demographic and clinical characteristics of the children in some instances were statistically significant, they only accounted for a small amount of the total explained variance.</p> <p>Conclusion</p> <p>Accessibility to the clinic and involvement of the parents in treatment are much stronger predictors of parental experiences with outpatient CAMHS than are demographic and clinical variables. Accessibility and involvement are at least partly influenced by the clinics themselves, and hence parental satisfaction may be enhanced by making the clinics more accessible and by involving the parents/caregivers in the treatment.</p
The bromotyrosine derivative Ianthelline isolated from the Arctic marine sponge Stryphnus fortis inhibits marine micro- and macrobiofouling
International audienceThe inhibition of marine biofouling by the bromotyrosine derivative ianthelline, isolated from the Arctic marine sponge Stryphnus fortis, is described. All major stages of the fouling process are investigated. The effect of ianthelline on adhesion and growth of marine bacteria and microalgae is tested to investigate its influence on the initial microfouling process comparing with the known marine antifoulant barettin as a reference. Macrofouling is studied via barnacle (Balanus improvisus) settlement assays and blue mussel (Mytilus edulis) phenoloxidase inhibition. Ianthelline is shown to inhibit both marine micro-and macrofoulers with a pronounced effect on marine bacteria (minimum inhibitory concentration (MIC) values 0.1-10 mu g/mL) and barnacle larval settlement (IC50= 3.0 mu g/mL). Moderate effects are recorded on M. edulis (IC50= 45.2 mu g/mL) and microalgae, where growth is more affected than surface adhesion. The effect of ianthelline is also investigated against human pathogenic bacteria. Ianthelline displayed low micromolar MIC values against several bacterial strains, both Gram positive and Gram negative, down to 2.5 mu g/mL. In summary, the effect of ianthelline on 20 different representative marine antifouling organisms and seven human pathogenic bacterial strains is presented
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