The Hollybank Challenges: AT for People with Profound Disabilities

The use of Assistive Technology with people with profound and multiple disabilities is a specialised subfield. Drawing on its authors' experiences and observations at a UK charitable foundation that offers specialised educational, residential and therapeutic facilities, this paper describes the distinct challenges that present themselves when applying AT to address the needs of this often-overlooked sector of the community. It is hoped that this will help raise awareness and contribute to improving the overall quality of AT provision in this area

Radiation calculations for the ATLAS detector and experimental hall

This paper describes the calculations performed to characterise the radiation field in the ATLAS detector at the LHC and to design the shielding of the detector and experimental areas. After a short description of the ATLAS detector, the simulations made with the MC code FLUKA are described in some detail. The radiation fields calculated in the inner cavity, in the calorimeters, in the experimental cavern, in the shafts and in an external skyshine region are presented

Coherent Optimal Control of Multiphoton Molecular Excitation

We give a framework for molecular multiphoton excitation process induced by an optimally designed electric field. The molecule is initially prepared in a coherent superposition state of two of its eigenfunctions. The relative phase of the two superposed eigenfunctions has been shown to control the optimally designed electric field which triggers the multiphoton excitation in the molecule. This brings forth flexibility in desiging the optimal field in the laboratory by suitably tuning the molecular phase and hence by choosing the most favorable interfering routes that the system follows to reach the target. We follow the quantum fluid dynamical formulation for desiging the electric field with application to HBr molecule.Comment: 5 figure

Transport of Fungal Symbionts by Mountain Pine Beetles

The perpetuation of symbiotic associations between bark beetles (Coleoptera: Curculionidae: Scolytinae) and ophiostomatoid fungi requires the consistent transport of fungi by successive beetle generations to new host trees. We used scanning electron microscopy and culture methods to investigate fungal transport by the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins. MPB transports its two main fungal associates, Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield and Ophiostoma montium (Rumbold) von Arx, in sac-like mycangia on the maxillary cardines as well as on the exoskeleton. Although spores of both species of fungi were observed on MPB exoskeletons, often in pits, O. montium spores were generally more abundant than G. clavigera spores. However, a general scarcity of spores of either species on MPB exoskeletons compared with numbers on scolytines that lack sac-like mycangia indicates that fungal transport exteriorly on MPBs is incidental rather than adaptive. Conidia were the dominant spore type transported regardless of location or species; however, our results suggest that once acquired in mycangia, conidia may reproduce in a yeast-like form and even produce hypha-like strands and compact conidiophore-like structures. Fungi that propagate in mycangia may provide beetles with a continual source of inocula during the extended egg-laying period

Imaging faint brown dwarf companions close to bright stars with a small, well-corrected telescope aperture

We have used our 1.6 m diameter off-axis well-corrected sub-aperture (WCS) on the Palomar Hale telescope in concert with a small inner-working-angle (IWA) phase-mask coronagraph to image the immediate environs of a small number of nearby stars. Test cases included three stars (HD 130948, HD 49197 and HR7672) with known brown dwarf companions at small separations, all of which were detected. We also present the initial detection of a new object close to the nearby young G0V star HD171488. Follow up observations are needed to determine if this object is a bona fide companion, but its flux is consistent with the flux of a young brown dwarf or low mass M star at the same distance as the primary. Interestingly, at small angles our WCS coronagraph demonstrates a limiting detectable contrast comparable to that of extant Lyot coronagraphs on much larger telescopes corrected with current-generation AO systems. This suggests that small apertures corrected to extreme adaptive optics (ExAO) levels can be used to carry out initial surveys for close brown dwarf and stellar companions, leaving followup observations for larger telescopes.Comment: accepted for publication in the Astrophysical Journa

Indium diffusion in the chemical potential gradient at an In0.53Ga0.47As/In0.52Al0.48As interface

We have measured the distribution of group III metals at In0.53Ga0.47As/In0.52Al0.48As interfaces before and after annealing at 1085 K. We find little evidence for Al interdiffusion, but the Ga concentration profiles show some broadening on annealing. Also, the originally nearly constant In profiles develop strong modulations with near discontinuities at the original interfaces. This phenomenon is explained and modeled in terms of In diffusion in the chemical potential gradient established by the disparity of the Al and Ga mobilities and the requirement of III‐V stoichiometry in the alloys.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70043/2/APPLAB-52-24-2055-1.pd

Impurity‐induced layer disordering of In0.53Ga0.47As/In0.52Al0.48As heterostructures

Impurity‐induced layer disordering of In0.53 Ga0.47 As/In0.52 Al0.48 As heterostructures grown by molecular beam epitaxy has been observed by Auger electron spectroscopy depth profiling. We find that Si+ ion implantation to concentrations greater than 2×1019 atoms cm−3 enhances the intermixing of Ga and Al in these heterostructures at an annealing temperature of 1075 K. However, the relatively high temperature which is required to activate the interdiffusion of Ga and Al in the region of high Si concentration is sufficient to induce In diffusion in regions of lower Si concentration. Zinc diffusion is found to completely intermix the Ga and Al in the heterolayers at temperatures as low as 825 K, which is below the temperature at which significant In diffusion occurs in undoped regions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70858/2/APPLAB-53-23-2302-1.pd

Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes

We present the Suzaku broad band observations of two AGNs detected by the Swift/BAT hard X-ray (>15 keV) survey that did not have previous X-ray data, Swift J0601.9-8636 and Swift J0138.6-4001. The Suzaku spectra reveals in both objects a heavily absorbed power law component with a column density of NH =~ 10^{23.5-24} cm^{-2} that dominates above 10 keV, and an intense reflection component with a solid angle >~ $2\pi$ from a cold, optically thick medium. We find that these AGNs have an extremely small fraction of scattered light from the nucleus, <~ 0.5% with respect to the intrinsic power law component. This indicates that they are buried in a very geometrically-thick torus with a small opening angle and/or have unusually small amount of gas responsible for scattering. In the former case, the geometry of Swift J0601.9-8636 should be nearly face-on as inferred from the small absorption for the reflection component. The discovery of two such objects in this small sample implies that there must be a significant number of yet unrecognized, very Compton thick AGNs viewed at larger inclination angles in the local universe, which are difficult to detect even in the currently most sensitive optical or hard X-ray surveys.Comment: 4 pages, 3 figures, accepted for publication in ApJ Lette