12,493 research outputs found
Underlying symmetries of realistic interactions and the nuclear many-body problem
The present study brings forward important information, within the framework
of spectral distribution theory, about the types of forces that dominate three
realistic interactions, CD-Bonn, CDBonn+ 3terms and GXPF1, in nuclei and their
ability to account for many-particle effects such as the formation of
correlated nucleon pairs and enhanced quadrupole collective modes.
Like-particle and proton-neutron isovector pairing correlations are described
microscopically by a model interaction with Sp(4) dynamical symmetry, which is
extended to include an additional quadrupole-quadrupole interaction. The
analysis of the results for the 1f7/2 level shows that both CD-Bonn+3terms and
GXPF1 exhibit a well-developed pairing character compared to CD-Bonn, while the
latter appears to build up more (less) rotational isovector T = 1 (isoscalar T
= 0) collective features. Furthermore, the three realistic interactions are in
general found to correlate strongly with the pairing+quadrupole model
interaction, especially for the highest possible isospin group of states where
the model interaction can be used to provide a reasonable description of the
corresponding energy spectra.Comment: 12 pages, 4 figure
Remote sensing applications to forest vegetation classification and conifer vigor loss due to dwarf mistletoe
Criteria was established for practical remote sensing of vegetation stress and mortality caused by dwarf mistletoe infections in black spruce subboreal forest stands. The project was accomplished in two stages: (1) A fixed tower-tramway site in an infected black spruce stand was used for periodic multispectral photo coverage to establish basic film/filter/scale/season/weather parameters; (2) The photographic combinations suggested by the tower-tramway tests were used in low, medium, and high altitude aerial photography
Duality Between the Weak and Strong Interaction Limits for Randomly Interacting Fermions
We establish the existence of a duality transformation for generic models of
interacting fermions with two-body interactions. The eigenstates at weak and
strong interaction U possess similar statistical properties when expressed in
the U=0 and U=infinity eigenstates bases respectively. This implies the
existence of a duality point U_d where the eigenstates have the same spreading
in both bases. U_d is surrounded by an interval of finite width which is
characterized by a non Lorentzian spreading of the strength function in both
bases. Scaling arguments predict the survival of this intermediate regime as
the number of particles is increased.Comment: RevTex4, 4 pages, 4 figures. Accepted for publication at Phys. Rev.
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Remote sensing of vigor loss in conifers due to dwarf mistletoe
The initial operation of a multiband/multidate tower-tramway test site in northeastern Minnesota for the development of specifications for subsequent multiband aerial photography of more extensive study areas was completed. Multiband/multidate configurations suggested by the tower-tramway studies were and will be flown with local equipment over the Togo test site. This site was photographed by the NASA RB57F aircraft in August and September 1971. It appears that, of all the film/filter combinations attempted to date (including optical recombining of several spectral band images via photo enhancement techniques), Ektachrome infrared film with a Wratten 12 filter is the best for detecting dwarf mistletoe, and other tree diseases as well. Using this film/filter combination, infection centers are easily detectable even on the smallest photo scale (1:100,000) obtained on the Togo site
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Developing theory-informed interventions to implement evidence into practice: a systematic approach using the Theoretical Domains Framework
Background: There is little systematic operational guidance about how best to develop complex interventions to reduce the gap between practice and evidence. This article is one in a series of articles documenting the development and use of the Theoretical Domains Framework (TDF) to advance the science of implementation research.
Methods: The intervention was developed considering three main components: theory, evidence, and practical issues. We used a four-step approach, consisting of guiding questions, to direct the choice of the most appropriate components of an implementation intervention: Who needs to do what, differently? Using a theoretical framework, which barriers and enablers need to be addressed? Which intervention components (behaviour change techniques and mode(s) of delivery) could overcome the modifiable barriers and enhance the enablers? And how can behaviour change be measured and understood?
Results: A complex implementation intervention was designed that aimed to improve acute low back pain management in primary care. We used the TDF to identify the barriers and enablers to the uptake of evidence into practice and to guide the choice of intervention components. These components were then combined into a cohesive intervention. The intervention was delivered via two facilitated interactive small group workshops. We also produced a DVD to distribute to all participants in the intervention group. We chose outcome measures in order to assess the mediating mechanisms of behaviour change.
Conclusions: We have illustrated a four-step systematic method for developing an intervention designed to change clinical practice based on a theoretical framework. The method of development provides a systematic framework that could be used by others developing complex implementation interventions. While this framework should be iteratively adjusted and refined to suit other contexts and settings, we believe that the four-step process should be maintained as the primary framework to guide researchers through a comprehensive intervention development process
Dynamics of Perfectly Wetting Drops under Gravity
We study the dynamics of small droplets of polydimethylsiloxane (PDMS)
silicone oil on a vertical, perfectly-wetting, silicon wafer. Interference
videomicroscopy allows us to capture the dynamics of these droplets. We use
droplets with a volumes typically ranging from 100 to 500 nanolitres
(viscosities from 10 to 1000 centistokes) to understand long time derivations
from classical solutions. Past researchers used one dimensional theory to
understand the typical scaling for the position of the tip of the
droplet in time . We observe this regime in experiment for intermediate
times and discover a two-dimensional, similarity solution of the shape of the
droplet. However, at long times our droplets start to move more slowly down the
plane than the scaling suggests and we observe deviations in droplet
shape from the similarity solution. We match experimental data with simulations
to show these deviations are consistent with retarded van der Waals forcing
which should become significant at the small heights observed
Detecting Oak Wilt by False Color Infrared Aerial Photography
An aerial survey using false-color infrared film at scales of l :9,600 and l : 12,000 located 93.7% of the oak wilt infection centers ii:1 the 1,500-acre study area. The ground survey of the same area also located 93.7% of the infection centers but half of those found by this method were difficult to relocate because they were not correctly mapped. Whereas aerial survey usually missed only trees of small diameter, the ground survey missed trees as large as eight inches in diameter
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