10,847 research outputs found
Refractory chronic migraine: long-term follow-up using a refractory rating scale
Refractory chronic migraine (RCM) is often associated with disability and a low quality of life (QOL). RCM ranges in severity from mild to severe. There would be a benefit both clinically and in research use in categorizing RCM patients according to severity. This study utilized a unique RCM severity rating scale, tracking the clinical course over 10 years. A total of 129 patients, ages 19–72, were assigned a severity rating of 2–10 (10 = worst). Pain level and QOL were assessed. Over the 10 years, 73% of all pts. had a 30% or more decline in pain. Pain levels improved 45% in mild pts., 42% in mod. pts., and 36% in severe pts. Pain was the same, or worse, in 4% of mild, 15% of mod., and 18% of severe pts. QOL in the mild group improved 35% over 10 years. In moderate pts., QOL improved 32%, while for the severe group QOL improved 33%. While pain and QOL improved across all three groups at the end of 10 years, the severe group remained with significantly more pain and decreased QOL than in the milder groups. The medications that helped significantly included: opioids (63% of pts. utilized opioids), frequent triptans (31%), butalbital (17%), onabotulinumtoxinA (16%), stimulants (12%), and other “various preventives” (9%). RCM pts. were rated using a refractory rating scale with the clinical course assessed over 10 years. Pain and QOL improved in all groups. In the severe group, pain and QOL improved, but still lagged behind the mild and moderate groups. Opioids and (frequent) triptans were the most commonly utilized meds
Strain Hardening in Polymer Glasses: Limitations of Network Models
Simulations are used to examine the microscopic origins of strain hardening
in polymer glasses. While traditional entropic network models can be fit to the
total stress, their underlying assumptions are inconsistent with simulation
results. There is a substantial energetic contribution to the stress that rises
rapidly as segments between entanglements are pulled taut. The thermal
component of stress is less sensitive to entanglements, mostly irreversible,
and directly related to the rate of local plastic arrangements. Entangled and
unentangled chains show the same strain hardening when plotted against the
microscopic chain orientation rather than the macroscopic strain.Comment: 4 pages, 3 figure
Toward the End of Time
The null-brane space-time provides a simple model of a big crunch/big bang
singularity. A non-perturbative definition of M-theory on this space-time was
recently provided using matrix theory. We derive the fermion couplings for this
matrix model and study the leading quantum effects. These effects include
particle production and a time-dependent potential. Our results suggest that as
the null-brane develops a big crunch singularity, the usual notion of
space-time is replaced by an interacting gluon phase. This gluon phase appears
to constitute the end of our conventional picture of space and time.Comment: 31 pages, reference adde
Impact Ionization in ZnS
The impact ionization rate and its orientation dependence in k space is
calculated for ZnS. The numerical results indicate a strong correlation to the
band structure. The use of a q-dependent screening function for the Coulomb
interaction between conduction and valence electrons is found to be essential.
A simple fit formula is presented for easy calculation of the energy dependent
transition rate.Comment: 9 pages LaTeX file, 3 EPS-figures (use psfig.sty), accepted for
publication in PRB as brief Report (LaTeX source replaces raw-postscript
file
Hoplia equina (Coleoptera: Scarabaeidae) and Nontarget Capture Using 2-Tetradecanone-Baited Traps
Using bucket traps baited with 2-tetradecanone, the sex pheromone of Hoplia equina LeConte, an important pest of cranberries in Massachusetts, we investigated the effect of trap height, color, pheromone load, and lure aging on male capture, as well as captures of nontarget arthropods including pollinators. Male capture was inversely related to height of traps over the four heights tested (0, 20, 60, and 100 cm). Captures increased with increasing pheromone load over the doses of 0, 100, 300, and 600 μg, but captures at the highest load, 1,000 μg, were not significantly different from 300 or 600 μg. H. equina captures were strongly diurnal, with a flight period spanning ≈6 wk starting in mid-June. Vane color of traps (white, yellow, green, blue, red, black) did not affect H. equina capture but significantly influenced capture of nontargets, including pollinators. A bucket trap with the funnel opening at 20 cm, and green (or red) vanes, baited with 600 μg of 2-tetradecanone, was the optimal design for high male capture and low nontarget capture. The low-cost capture of over 50,000 H. equina on a 2.4-ha commercial bog in Massachusetts with this lure-trap combination indicates the feasibility of mass trapping for managing established infestations of H. equin
Melting-freezing cycles in a relatively sheared pair of crystalline monolayers
The nonequilibrium dynamical behaviour that arises when two ordered
two-dimensional monolayers of particles are sheared over each other is studied
in Brownian dynamics simulations. A curious sequence of nonequilibrium states
is observed as the driving rate is increased, the most striking of which is a
sliding state with irregular alternation between disordered and ordered states.
We comment on possible mechanisms underlying these cycles, and experiments that
could observe them.Comment: 7 pages, 8 figures, minor changes in text and figures, references
adde
Kidney Patients’ Intention to Receive a Deceased Donor Transplant: Development of Stage of Change, Decisional Balance and Self-efficacy Measures
In order to sustain life, patients whose kidneys fail must receive dialysis or obtain a transplant. This study reports on the development and validation of measures of Stage of Change, Decisional Balance and Self-efficacy based on the Transtheoretical Model (TTM) to assess patients’ readiness to receive a deceased donor transplant. We surveyed 293 transplant-eligible kidney patients about their deceased donation readiness. Exploratory and confirmatory analyses for all measures demonstrated factor structures similar to previous application of the TTM to other health behaviors, excellent model fit and good internal and external validity. These brief, reliable instruments with good psychometric properties can guide the development of improved, individually-tailored transplant education for patients
Finite-element analysis of contact between elastic self-affine surfaces
Finite element methods are used to study non-adhesive, frictionless contact
between elastic solids with self-affine surfaces. We find that the total
contact area rises linearly with load at small loads. The mean pressure in the
contact regions is independent of load and proportional to the rms slope of the
surface. The constant of proportionality is nearly independent of Poisson ratio
and roughness exponent and lies between previous analytic predictions. The
contact morphology is also analyzed. Connected contact regions have a fractal
area and perimeter. The probability of finding a cluster of area drops as
where increases with decreasing roughness exponent. The
distribution of pressures shows an exponential tail that is also found in many
jammed systems. These results are contrasted to simpler models and experiment.Comment: 13 pages, 15 figures. Replaced after changed in response to referee
comments. Final two figures change
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