Spectroscopy of drums and quantum billiards: perturbative and non-perturbative results

We develop powerful numerical and analytical techniques for the solution of the Helmholtz equation on general domains. We prove two theorems: the first theorem provides an exact formula for the ground state of an arbirtrary membrane, while the second theorem generalizes this result to any excited state of the membrane. We also develop a systematic perturbative scheme which can be used to study the small deformations of a membrane of circular or square shapes. We discuss several applications, obtaining numerical and analytical results.Comment: 29 pages, 12 figures, 7 tabl

Magnetism and Magnetic Isomers in Free Chromium Clusters

We have used the Stern-Gerlach deflection technique to study magnetism in chromium clusters of 20-133 atoms. Between 60 K and 100 K, we observe that these clusters have large magnetic moments and respond superparamagnetically to applied magnetic fields. Using superparamagnetic theory, we have determined the moment per atom for each cluster size and find that it often far exceeds the moment per atom present anywhere in the bulk antiferromagnetic lattice. Remarkably, our cluster beam contains two magnetically distinguishable forms of each cluster size with >= 34 atoms. We attribute this observation to structural isomers

Processing deficits in monitoring analog and digital displays: Implications for attentional theory and mental-state estimation research

Subjects performed short term memory tasks, involving both spatial and verbal components, and a visual monitoring task involving either analog or digital display formats. These two tasks (memory vs. monitoring) were performed both singly and in conjunction. Contrary to expectations derived from multiple resource theories of attentional processes, there was no evidence that when the two tasks involved the same cognitive codes (i.e., either both spatial or both verbal/linguistics) there was more of a dual task performance decrement than when the two tasks employed different cognitive codes/processes. These results are discussed in terms of their implications for theories of attentional processes and also for research in mental state estimation

Fabrication and evaluation of advanced titanium and composite structural panels

Advanced manufacturing methods for titanium and composite material structures are being developed and evaluated. The focus for the manufacturing effort is the fabrication of full-scale structural panels which replace an existing shear panel on the upper wing surface of the NASA YF-12 aircraft. The program involves design, fabrication, ground testing, and Mach 3 flight service of full-scale structural panels and laboratory testing of representative structural element specimens

Swing fence flood crossing for creeks in the Kimberleys

FENCING is the basis of the regeneration programme on the eroded Ord River catchment area, and the fences constructed must cross numerous creeks. But heavy downpours of short duration characterise the wet season experienced in this area. Because the rain falls on to bare, compacted ground, run-off is intense and gullies and creeks rise rapidly, causing serious damage to conventional fences and flood gates across watercourses

Promising results on West Kimberley pindan country

IN the 22 to 28 inch rainfall belt of the West Kimberley area of Western Australia are extensive areas of what is locally known as pindan country. The term pindan refers to a light red or yellow sandy soil type supporting scattered Eucalypts, sparse-dense wattle scrub and grasses such as curly spinifex, ribbon grass and native sorghum

EAPC task force on education for psychologists in palliative care

It is argued that psychological aspects of care and psychosocial problems are essential components of palliative care. However, the provision of appropriate services remains somewhat arbitrary. Unlike medical and nursing care, which are clearly delivered by doctors and nurses respectively, psychological and psychosocial support in palliative care are not assigned exclusively to psychologists. It is generally expected that all professionals working in palliative care should have some knowledge of the psychological dynamics in terminal illness, as well as skills in communication and psychological risk assessment. On the one hand, palliative care education programmes for nurses and doctors comprise a considerable amount of psychological and psychosocial content. On the other hand, only a few palliative care associations provide explicit information on the role and tasks of psychologists in palliative care. Psychologists’ associations do not deal much with this issue either. If they refer to it at all, it is in the context of the care of the aged, end-of-life care or how to deal with grief

The Strongest 100 Point Radio Sources in the LMC at 1.4 GHz

We present the 100 strongest 1.4 GHz point sources from a new mosaic image in the direction of the Large Magellanic Cloud (LMC). The observations making up the mosaic were made over a ten year period and were combined with Parkes single dish data at 1.4 GHz to complete the image for short spacing. An initial list of co-identifications within 10" at 0.843, 4.8 and 8.6 GHz consisted of 2682 sources. Elimination of extended objects and artifact noise allowed the creation of a refined list containing 1988 point sources. Most of these are presumed to be background objects seen through the LMC; a small portion may represent compact H II regions, young SNRs and radio planetary nebulae. For the 1988 point sources we find a preliminary average spectral index of -0.53 and present a 1.4 GHz image showing source location in the direction of the LMC.Comment: 8 pages, 2 figure

Nuclear Corrections to Hyperfine Structure in Light Hydrogenic Atoms

Hyperfine intervals in light hydrogenic atoms and ions are among the most accurately measured quantities in physics. The theory of QED corrections has recently advanced to the point that uncalculated terms for hydrogenic atoms and ions are probably smaller than 0.1 parts per million (ppm), and the experiments are even more accurate. The difference of the experiments and QED theory is interpreted as the effect on the hyperfine interaction of the (finite) nuclear charge and magnetization distributions, and this difference varies from tens to hundreds of ppm. We have calculated the dominant component of the 1s hyperfine interval for deuterium, tritium and singly ionized helium, using modern second-generation potentials to compute the nuclear component of the hyperfine splitting for the deuteron and the trinucleon systems. The calculated nuclear corrections are within 3% of the experimental values for deuterium and tritium, but are about 20% discrepant for singly ionized helium. The nuclear corrections for the trinucleon systems can be qualitatively understood by invoking SU(4) symmetry.Comment: 26 pages, 1 figure, latex - submitted to Physical Review