6,964 research outputs found
The Relative Importance of Search versus Credence Product Attributes: Organic and Locally Grown
Organic foods and local foods have come to the forefront of consumer issues, due to concerns about nutrition, health, sustainability, and food safety. A conjoint analysis experiment quantified the relative importance of, and trade-offs between, apple search and experience attributes (quality/blemishes, size, flavor), credence attributes (conventional vs. organic production method, local origin vs. product of USA vs. imported), and purchase price when buying apples. Quality is the most important apple attribute. Production method—organic versus conventional—had no significant impact on preferences.conjoint analysis, organic, locally grown, credence attributes, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing,
Ab Initio Treatment of Collective Correlations and the Neutrinoless Double Beta Decay of Ca
Working with Hamiltonians from chiral effective field theory, we develop a
novel framework for describing arbitrary deformed medium-mass nuclei by
combining the in-medium similarity renormalization group with the generator
coordinate method. The approach leverages the ability of the first method to
capture dynamic correlations and the second to include collective correlations
without violating symmetries. We use our scheme to compute the matrix element
that governs the neutrinoless double beta decay of Ca to Ti, and
find it to have the value , near or below the predictions of most
phenomenological methods. The result opens the door to ab initio calculations
of the matrix elements for the decay of heavier nuclei such as Ge,
Te, and Xe.Comment: 6 pages, 4 figures and 1 table. supplementary material included.
version to be publishe
Impact of exercise on articular cartilage in people at risk of, or with established, knee osteoarthritis: a systematic review of randomised controlled trials
This project is supported by a European Union Seventh Framework Programme (FP7-PEOPLE-2013-ITN; KNEEMO) under grant agreement number 607510.Peer reviewedPostprin
On the Nature of the Strong Emission-Line Galaxies in Cluster Cl 0024+1654: Are Some the Progenitors of Low Mass Spheroidals?
We present new size, line ratio, and velocity width measurements for six
strong emission-line galaxies in the galaxy cluster, Cl 0024+1654, at redshift
z~0.4. The velocity widths from Keck spectra are all narrow (30<sigma<120
km/s), with three profiles showing double peaks. Four galaxies have low masses
(M<10^{10} Mo). Whereas three galaxies were previously reported to be possible
AGNs, none exhibit AGN-like emission line ratios or velocity widths. Two or
three appear as very blue spirals with the remainder more akin to luminous H-II
galaxies undergoing a strong burst of star formation. We propose that after the
burst subsides, these galaxies will transform into quiescent dwarfs, and are
thus progenitors of some cluster spheroidals (We adopt the nomenclature
suggested by Kormendy & Bender (1994), i.e., low-density, dwarf ellipsoidal
galaxies like NGC 205 are called `spheroidals' instead of `dwarf ellipticals')
seen today.Comment: 14 pages + 2 figures + 1 table, LaTeX, Acc. for publ. in ApJL also
available at http://www.ucolick.org/~deep/papers/papers.htm
Ankle dexterity is less impaired than muscle strength in incomplete spinal cord lesion
Background : Motor assessment after incomplete spinal cord injury (iSCI) currently consists of tests for muscle strength (manual muscle testing) and gait. The ability to adequately time a movement, an aspect of dexterity, is not tested. Thus, this study assessed the timing of ankle dorsiflexion in iSCI patients in the supine position and during gait and examined its relation to measures for muscle strength, corticospinal conductivity and gait speed. Methods : In 12 subjects with iSCI and 12 matched controls, timing of ankle dorsiflexion was tested by means of auditory-paced dorsiand plantar-flexion movements at three frequencies in the supine position and by determining initiation and termination of dorsiflexion in swing during gait. In addition, maximal movement velocity (MMV) in the ankle task, maximal voluntary contraction (MVC), corticospinal conductivity (motor evoked potentials (MEP)) and gait speed (10 Meter Walk Test) were assessed. Results : The groups did not significantly differ in timing of ankle dorsiflexion, neither in the supine position nor in gait. However, they significantly differed in MMV at all frequencies, MEP latency, MEP amplitude and gait speed. In contrast to ankle timing in the supine position, the onset of dorsiflexion in swing during gait significantly correlated to the dynamic MEP parameters. Conclusions : Although MMV and gait speed were significantly reduced, timing of ankle dorsiflexion, both in the supine position and during gait,was less impaired in iSCI patients. This indicates that the loss of strength, particularly of dynamic strength, is the major motor impairment in iSCI, which might be considered when assessing treatment intervention
A precursor state to unconventional superconductivity in CeIrIn
We present sensitive measurements of the Hall effect and magnetoresistance in
CeIrIn down to temperatures of 50 mK and magnetic fields up to 15 T. The
presence of a low temperature coherent Kondo state is established. Deviations
from Kohler's rule and a quadratic temperature dependence of the cotangent of
the Hall angle are reminiscent of properties observed in the high temperature
superconducting cuprates. The most striking observation pertains to the
presence of a \textit{precursor} state--characterized by a change in the Hall
mobility--that appears to precede the superconductivity in this material, in
similarity to the pseudogap in the cuprate high superconductors.Comment: 4 figure
The role of stoichiometric vacancy periodicity in pressure-induced amorphization of the Ga2SeTe2 semiconductor alloy
We observe that pressure-induced amorphization of Ga2SeTe2 (a III-VI
semiconductor) is directly influenced by the periodicity of its intrinsic
defect structures. Specimens with periodic and semi-periodic two-dimensional
vacancy structures become amorphous around 10-11 GPa in contrast to those with
aperiodic structures, which amorphize around 7-8 GPa. The result is a notable
instance of altering material phase-change properties via rearrangement of
stoichiometric vacancies as opposed to adjusting their concentrations. Based on
our experimental findings, we posit that periodic two-dimensional vacancy
structures in Ga2SeTe2 provide an energetically preferred crystal lattice that
is less prone to collapse under applied pressure. This is corroborated through
first-principles electronic structure calculations, which demonstrate that the
energy stability of III-VI structures under hydrostatic pressure is highly
dependent on the configuration of intrinsic vacancies
High spin polarization in the ferromagnetic filled skutterudites KFe4Sb12 and NaFe4Sb12
The spin polarization of ferromagnetic alkali-metal iron antimonides KFe4Sb12
and NaFe4Sb12 is studied by point-contact Andreev reflection using
superconducting Nb and Pb tips. From these measurements an intrinsic transport
spin polarization Pt of 67% and 60% for the K and Na compound, respectively, is
inferred which establishes these materials as a new class of highly spin
polarized ferromagnets. The results are in accord with band structure
calculations within the local spin density approximation (LSDA) that predict
nearly 100% spin polarization in the density of states. We discuss the impact
of calculated Fermi velocities and spin fluctuations on Pt.Comment: Pdf file with fi
Logarithmic behavior of degradation dynamics in metal--oxide semiconductor devices
In this paper the authors describe a theoretical simple statistical modelling
of relaxation process in metal-oxide semiconductor devices that governs its
degradation. Basically, starting from an initial state where a given number of
traps are occupied, the dynamics of the relaxation process is measured
calculating the density of occupied traps and its fluctuations (second moment)
as function of time. Our theoretical results show a universal logarithmic law
for the density of occupied traps , i.e., the degradation is logarithmic and its amplitude depends on the
temperature and Fermi Level of device. Our approach reduces the work to the
averages determined by simple binomial sums that are corroborated by our Monte
Carlo simulations and by experimental results from literature, which bear in
mind enlightening elucidations about the physics of degradation of
semiconductor devices of our modern life
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