2,002 research outputs found
Properties of cryogenically worked materials Interim report
Cryogenically worked materials during strain hardenin
Do Homebuyers Care about the 'Quality' of Natural Habitats?
We study if homebuyers in Tucson, Arizona care about the condition of natural habitats and if they have preferences between natural and manmade habitats. Using field work data we examine whether homebuyers willingness to pay is influenced by the biological condition of the neighboring riparian habitat and how homebuyers value alternative manmade green areas, specifically golf courses. We also explore the relationship between the field data and remote sensing vegetation indices. The results of a hedonic analysis of houses that sold within 0.2 miles of 51 stratified-random selected riparian survey sites in Tucson, Arizona reveals that homebuyers significantly value habitat quality and negatively value manmade park-like features. Homebuyers are willing to pay twenty percent more to live near a riparian corridor that is densely vegetated and contains more shrub and tree species, particularly species that are dependent on perennial water flow. These environmental premiums are significant, outweighing structural factors such as an additional garage or swimming pool. Likewise, proximity to a riparian habitat with low biological quality or to a golf course lowers property values.Land Economics/Use,
Exploring a rheonomic system
A simple and illustrative rheonomic system is explored in the Lagrangian
formalism. The difference between Jacobi's integral and energy is highlighted.
A sharp contrast with remarks found in the literature is pointed out. The
non-conservative system possess a Lagrangian not explicitly dependent on time
and consequently there is a Jacobi's integral. The Lagrange undetermined
multiplier method is used as a complement to obtain a few interesting
conclusion
Editorial
This guest-edited Special Issue of RERM celebrates the enormous contribution that Professor Jeanette Rhedding-Jones made to the field of educational research over her life time
How do I sound to me? Perceived changes in communication in Parkinson's disease
Objective: To examine self and carer perceived changes in communication associated with Parkinson's disease and relate these to speech intelligibility, gender, age and other disease measures.
Design: Cross-sectional survey of a hospital- and community-based sample of 176 people with Parkinson's disease and their carers using a questionnaire based on semantic differential techniques.
Participants: One hundred and four people with Parkinson's disease with no history of communication difficulties prior to onset of their Parkinson's disease and 45 primary carers who returned completed questionnaires.
Main outcome measures: Differences in ratings for `before' the onset of Parkinson's disease versus present status.
Results: There was a strong perception of negative impact on communication between `before' and `now', irrespective of age and gender and largely independent of disease severity and duration, intelligibility and cognitive status. Activities of daily living (assessed by Unified Parkinson's Disease Rating Scale (UPDRS) II) and depression rating scale scores had the strongest association with change (adjusted R 2 0.27). There was a significant correlation between the rank order of perceived change in features examined in people with Parkinson's disease versus their carers, though in general carers rated change as having less impact.
Conclusions: Parkinson's disease exercises a strong influence on communication even before apparent alterations to intelligibility or motor status
Is the classical Bukhvostov-Lipatov model integrable? A Painlev\'e analysis
In this work we apply the Weiss, Tabor and Carnevale integrability criterion
(Painlev\'e analysis) to the classical version of the two dimensional
Bukhvostov-Lipatov model. We are led to the conclusion that the model is not
integrable classically, except at a trivial point where the theory can be
described in terms of two uncoupled sine-Gordon models
Double photo-ionization of He near a polarizable surface
We calculate the differential cross-section of the direct double
photo-ionization of He physisorbed on a polarizable surface. By including the
influence of the surface potential in the correlated two-electron final state
wavefunction, we show that the differential cross-section carries detailed
information on the electronic correlations at the surface. In particular,
photo-emission along opposite directions, which is prohibited in the free
space, is allowed if the surface potential is long-ranged.Comment: To appear in Phys. Rev. B - Rapid Comm. - 4 pages, 2 PostScript
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Spectral isolation of naturally reductive metrics on simple Lie groups
We show that within the class of left-invariant naturally reductive metrics
on a compact simple Lie group , every
metric is spectrally isolated. We also observe that any collection of
isospectral compact symmetric spaces is finite; this follows from a somewhat
stronger statement involving only a finite part of the spectrum.Comment: 19 pages, new title and abstract, revised introduction, new result
demonstrating that any collection of isospectral compact symmetric spaces
must be finite, to appear Math Z. (published online Dec. 2009
Local modes, phonons, and mass transport in solid He
We propose a model to treat the local motion of atoms in solid He as a
local mode. In this model, the solid is assumed to be described by the Self
Consistent Harmonic approximation, combined with an array of local modes. We
show that in the bcc phase the atomic local motion is highly directional and
correlated, while in the hcp phase there is no such correlation. The correlated
motion in the bcc phase leads to a strong hybridization of the local modes with
the T phonon branch, which becomes much softer than that obtained
through a Self Consistent Harmonic calculation, in agreement with experiment.
In addition we predict a high energy excitation branch which is important for
self-diffusion. Both the hybridization and the presence of a high energy branch
are a consequence of the correlation, and appear only in the bcc phase. We
suggest that the local modes can play the role in mass transport usually
attributed to point defects (vacancies). Our approach offers a more overall
consistent picture than obtained using vacancies as the predominant point
defect. In particular, we show that our approach resolves the long standing
controversy regarding the contribution of point defects to the specific heat of
solid He.Comment: 10 pages, 10 figure
The Drosophila Melanogaster RAD54 Homolog, DmRAD54, Is Involved in the Repair of Radiation Damage and Recombination
The RAD54 gene of Saccharomyces cerevisiae plays a crucial role in recombinational repair of double-strand breaks in DNA. Here the isolation and functional characterization of the RAD54 homolog of the fruit fly Drosophila melanogaster, DmRAD54, are described. The putative Dmrad54 protein displays 46 to 57% identity to its homologs from yeast and mammals. DmRAD54 RNA was detected at all stages of fly development, but an increased level was observed in early embryos and ovarian tissue. To determine the function of DmRAD54, a null mutant was isolated by random mutagenesis. DmRAD54-deficient flies develop normally, but the females are sterile. Early development appears normal, but the eggs do not hatch, indicating an essential role for DmRAD54 in development. The larvae of mutant flies are highly sensitive to X rays and methyl methanesulfonate. Moreover, this mutant is defective in X- ray-induced mitotic recombination as measured by a somatic mutation and recombination test. These phenotypes are consistent with a defect in the repair of double-strand breaks and imply that the RAD54 gene is crucial in repair and recombination in a multicellular organism. The results also indicate that the recombinational repair pathway is functionally conserved in evolution
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