Although psychological distress and cognitive dysfunction are well documented in adults with multiple sclerosis (MS), they are poorly understood in children with the disease. Psychosocial difficulty ...experienced by children and adolescents with MS involves factors common to all chronic illnesses in children, as well as MS-specific factors. The psychosocial manifestations of the disease may affect the patient's self-image, role functioning, mood, and cognition to adversely affect schooling, interpersonal relationships, and treatment compliance. Furthermore, the impact of having a family member with MS may affect overall family functioning. Assessment and interventions for psychosocial and cognitive problems in pediatric MS should be multidisciplinary in nature and address the child's functioning at home, school, and among peers, as well as the effect on the family.
Eight nearby stars with known giant planets have been searched for thermal emission in the submillimetre arising from dust debris. The null results imply quantities of dust typically less than 0.02 ...Earth masses per star. Conversely, literature data for 20 Sun-like stars with debris discs show that ≤ 5 per cent have gas giants inside a few astronomical units — but the dust distribution suggests that nearly all have more distant planets. The lack of overlap in these systems — i.e. few stars possess both inner planets and a disc — indicates that these phenomena either are not connected or are mutually exclusive. Comparison with an evolutionary model shows that debris masses are predicted to be low by the stellar ages of 2–8 Gyr (unless the colliding parent bodies are quite distant, located beyond 100–200 au), but it remains to be explained why stars that do have debris should preferentially only have distant planets. A simple idea is proposed that could produce these largely different systems, invoking a difference in the primordial disc mass. Large masses promote fast gas giant growth and inwards migration, whereas small masses imply slow evolution, low-mass gas giants and outwards migration that increases the collision rate of Kuiper Belt-like objects. This explanation neglects other sources of diversity between discs (such as density and planetesimal composition and orbits), but it does have the merit of matching the observational results.
The calibration of ground-based submillimetre observations has always been a difficult process. We discuss how to overcome the limitations imposed by the submillimetre atmosphere. Novel ways to ...improve line-of-sight opacity estimates are presented, resulting in tight relations between opacities at different wavelengths. The submillimetre camera SCUBA, mounted on the James Clerk Maxwell Telescope (JCMT), is the first large-scale submillimetre array, and as such is ideal for combating the effects of the atmosphere. For example, we find that the off-source pixels are crucial for removing sky noise. Benefiting from several years of SCUBA operation, a data base of deep SCUBA observations has been constructed to help us understand better the nature of sky noise and the effects of the atmosphere on instrument sensitivity. This has revealed several results. First, there is evidence for positive correlations between sky noise and seeing and sky noise and sky opacity. Furthermore, 850-μm and 450-μm sky noise are clearly correlated, suggesting that 450-μm data may be used to correct 850-μm observations for sky noise. Perhaps most important of all: if off-source bolometers are used for sky noise removal, there is no correlation between instrument sensitivity and chop throw, for chop throws out to 180 arcsec. Understanding the effects of submillimetre seeing is also important, and we find that the JCMT beam is not significantly broadened by seeing, nor is there an obvious correlation between seeing and pointing excursions.
We obtained Herschel PACS and SPIRE images of the thermal emission of the debris disk around the A5V star β Pic. The disk is well resolved in the PACS filters at 70, 100, and 160 μm. The surface ...brightness profiles between 70 and 160 μm show no significant asymmetries along the disk, and are compatible with 90% of the emission between 70 and 160 μm originating in a region closer than 200 AU to the star. Although only marginally resolving the debris disk, the maps obtained in the SPIRE 250–500 μm filters provide full-disk photometry, completing the SED over a few octaves in wavelength that had been previously inaccessible. The small far-infrared spectral index (β = 0.34) indicates that the grain size distribution in the inner disk (<200 AU) is inconsistent with a local collisional equilibrium. The size distribution is either modified by non-equilibrium effects, or exhibits a wavy pattern, caused by an under-abundance of impactors which have been removed by radiation pressure.
A polarimeter has been built for use with the Submillimetre Common-User Bolometer Array (SCUBA), on the James Clerk Maxwell Telescope (JCMT) in Hawaii. SCUBA is the first of a new generation of ...highly sensitive submillimetre cameras, and the UK/Japan Polarimeter adds a polarimetric imaging/photometry capability in the wavelength range 350 to 2000 μm. Early science results range from measuring the synchrotron polarization of the black hole candidate Sgr A* to mapping magnetic fields inferred from polarized dust emission in Galactic star-forming clouds. We describe the instrument design, performance, observing techniques and data reduction processes, along with an assessment of the current and future scientific capability.
... Ceti is a nearby, mature G-type star very similar to our Sun, with a massive Kuiper Belt analogue and possible multiplanet system that has been compared to our Solar system. We present Herschel ...Space Observatory images of the debris disc, finding the disc is resolved at 70 ...m and 160 ...m, and marginally resolved at 250 ...m. The Herschel images and infrared photometry from the literature are best modelled using a wide dust annulus with an inner edge between 1 and 10 au and an outer edge at ~55 au, inclined from face-on by 35... ± 10..., and with no significant azimuthal structure. We model the proposed tightly packed planetary system of five super-Earths and find that the innermost dynamically stable disc orbits are consistent with the inner edge found by the observations. The photometric modelling, however, cannot rule out a disc inner edge as close to the star as 1 au, though larger distances produce a better fit to the data. Dynamical modelling shows that the five-planet system is stable with the addition of a Neptune or smaller mass planet on an orbit outside 5 au, where the radial velocity data analysis would not have detected a planet of this mass. (ProQuest: ... denotes formulae/symbols omitted.)
We report the first demonstration of InAs FinFETs with fin width Formula Omitted in the range 25-35 nm, formed by inductively coupled plasma etching. The channel comprises defect-free, ...lattice-matched InAs with fin height Formula Omitted nm controlled by the use of an etch stop layer incorporated into the device heterostructure. For a gate length Formula Omitted, peak transconductance Formula Omitted is measured at Formula Omitted V demonstrating that electron transport in InAs fins can match planar devices.
We report the first demonstration of InAs FinFETs with fin width W fin in the range 25-35 nm, formed by inductively coupled plasma etching. The channel comprises defect-free, lattice-matched InAs ...with fin height H fin = 20 nm controlled by the use of an etch stop layer incorporated into the device heterostructure. For a gate length L g = 1 μm, peak transconductance gm,peak = 1430 μS/μm is measured at V d = 0.5 V demonstrating that electron transport in InAs fins can match planar devices.
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