5,484 research outputs found
Gravity gradient preliminary investigations, part 2: Lunar tidal gravity gradients and stresses (exhibit C)
Preliminary analysis of the gravity gradients associated with gravity tides on the moon caused by the earth indicates that the relative changes in the gradients are very irregular, and large, and about 15 times greater than those experienced on earth. Thus gradients, in preference to gravity tides themselves, may well be an important key in correlating tide effects with lunar transient events and moonquakes, and also in determining triggering mechanisms for crustal movement and faulting. Preliminary analysis of lunar crustal stresses and strains caused by lunar gravity tides indicates that these factors may be more direct causative agents or triggering mechanisms. In particular, the cubic dilation undergoes relatively large changes and is about 11 times greater on the moon than on earth. Thus it should be correspondingly more important
Improved laboratory gradiometer can be a field survey instrument
Improvements made to quartz gradiometer minimize or eliminate disturbing effects from known error sources and permit sensitivity of + or - 1 times 10 to the minus 9th power/sec sq or better and measuring accuracy of + or - 5 times 10 to the minus 9th power/sec sq
Gravity gradient preliminary investigations on exhibit ''A'' Final report
Quartz microbalance gravity gradiometer performance test
Expression patterns of chondrocyte genes cloned by differential display in tibial dyschondroplasia
AbstractTibial dyschondroplasia (TD) appears to involve a failure of the growth plate chondrocytes within growing long bones to differentiate fully to the hypertrophic stage, resulting in a mass of prehypertrophic chondrocytes which form the avascular TD lesion. Many biochemical and molecular markers of chondrocyte hypertrophy are absent from the lesion, or show reduced expression, but the cause of the disorder remains to be identified. As differentiation to the hypertrophic state is impaired in TD, we hypothesised that chondrocyte genes that are differentially expressed in the growth plate should show altered expression in TD. Using differential display, four genes, B-cadherin, EF2, HT7 and Ex-FABP were cloned from chondrocytes stimulated to differentiate to the hypertrophic stage in vitro, and their differential expression confirmed in vivo. Using semi-quantitative RT-PCR, the expression patterns of these genes were compared in chondrocytes from normal and TD growth plates. Surprisingly, none of these genes showed the pattern of expression that might be expected in TD lesion chondrocytes, and two of them, B-cadherin and Ex-FABP, were upregulated in the lesion. This indicates that the TD phenotype does not merely reflect the absence of hypertrophic marker genes, but may be influenced by more complex developmental mechanisms/defects than previously thought
Application of the ERTS system to the study of Wyoming resources with emphasis on the use of basic data products
Many potential users of ERTS data products and other aircraft and satellite imagery are limited to visual methods of analyses of these products. Illustrations are presented from Wyoming studies that have employed these standard data products for a variety of geologic and related studies. Possible economic applications of these studies are summarized. Studies include regional geologic mapping for updating and correcting existing maps and to supplement incomplete regional mapping; illustrations of the value of seasonal images in geologic mapping; specialized mapping of such features as sand dunes, playa lakes, lineaments, glacial features, regional facies changes, and their possible economic value; and multilevel sensing as an aid in mineral exploration. Examples of cooperative studies involving botanists, plant scientists, and geologists for the preparation of maps of surface resources that can be used by planners and for environmental impact studies are given
Computer Algebra meets Finite Elements: an Efficient Implementation for Maxwell's Equations
We consider the numerical discretization of the time-domain Maxwell's
equations with an energy-conserving discontinuous Galerkin finite element
formulation. This particular formulation allows for higher order approximations
of the electric and magnetic field. Special emphasis is placed on an efficient
implementation which is achieved by taking advantage of recurrence properties
and the tensor-product structure of the chosen shape functions. These
recurrences have been derived symbolically with computer algebra methods
reminiscent of the holonomic systems approach.Comment: 16 pages, 1 figure, 1 table; Springer Wien, ISBN 978-3-7091-0793-
Measuring atomic NOON-states and using them to make precision measurements
A scheme for creating NOON-states of the quasi-momentum of ultra-cold atoms
has recently been proposed [New J. Phys. 8, 180 (2006)]. This was achieved by
trapping the atoms in an optical lattice in a ring configuration and rotating
the potential at a rate equal to half a quantum of angular momentum . In this
paper we present a scheme for confirming that a NOON-state has indeed been
created. This is achieved by spectroscopically mapping out the anti-crossing
between the ground and first excited levels by modulating the rate at which the
potential is rotated. Finally we show how the NOON-state can be used to make
precision measurements of rotation.Comment: 14 preprint pages, 7 figure
Fit for work? Health, employability and challenges for the UK welfare reform agenda
This article introduces a special issue of Policy Studies entitled āFit for work? Health, employability and challenges for the UK welfare reform agendaā. Growing from a shared concern over the need to expand the evidence base around the processes that led to large numbers of people claiming disability benefits in the UK, it brings together contributions from leading labour market and social policy researchers providing evidence and commentary on major reforms to Incapacity Benefit (IB) in the UK. This special issue address three key questions: what are the main causes of the long-term rise in the number of people claiming IBs; what will reduce the number of claimants; and what is likely to deliver policy effectively and efficiently? This introduction first explains and examines the challenges to reforms to IB in the UK, and then, in conclusion, highlights the answers to the previous three questions ā first, labour market restructuring and marginalisation have driven the rise in numbers claiming IBs. Second, economic regeneration in the Britainās less prosperous areas coupled with intensive and sustained supply-side support measures will bring numbers down. Third, delivery need to be flexible and tailored to individual needs and needs to be able to access local and expert knowledge in a range of organisations, including Job Centre Plus, the NHS as well as the private and voluntary sectors
Ferromagnetic resonance force microscopy on a thin permalloy film
Ferromagnetic Resonance Force Microscopy (FMRFM) offers a means of performing
local ferromagnetic resonance. We have studied the evolution of the FMRFM force
spectra in a continuous 50 nm thick permalloy film as a function of probe-film
distance and performed numerical simulations of the intensity of the FMRFM
probe-film interaction force, accounting for the presence of the localized
strongly nonuniform magnetic field of the FMRFM probe magnet. Excellent
agreement between the experimental data and the simulation results provides
insight into the mechanism of FMR mode excitation in an FMRFM experiment.Comment: 9 pages, 2 figure
Vowel discrimination by hearing infants as a function of number of spectral channels
Reduced spectral resolution negatively impacts speech perception, particularly perception of vowels and consonant place. This study assessed impact of number of spectral channels on vowel discrimination by 6-month-old infants with normal hearing by comparing three listening conditions: Unprocessed speech, 32 channels, and 16 channels. Auditory stimuli (/ti/ and /ta/) were spectrally reduced using a noiseband vocoder and presented to infants with normal hearing via visual habituation. Results supported a significant effect of number of channels on vowel discrimination by 6-month-old infants. No differences emerged between unprocessed and 32-channel conditions in which infants looked longer during novel stimulus trials (i.e., discrimination). The 16-channel condition yielded a significantly different pattern: Infants demonstrated no significant difference in looking time to familiar vs novel stimulus trials, suggesting infants cannot discriminate /ti/ and /ta/ with only 16 channels. Results support effects of spectral resolution on vowel discrimination. Relative to published reports, young infants need more spectral detail than older children and adults to perceive spectrally degraded speech. Results have implications for development of perception by infants with hearing loss who receive auditory prostheses
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