541 research outputs found
The role of hip abductor strength on the frontal plane of gait in subjects with medial knee osteoarthritis
Objective: This study aimed to investigate the relationship of hip abductor strength with external hip and knee adduction moments, pain and physical function, and trunk, pelvis, and hip kinematics in the frontal plane during walking in subjects with medial knee osteoarthritis.
Methods: Twenty-five subjects with medial knee osteoarthritis were evaluated through an isokinetic strength test for hip abductor, three-dimensional gait analysis (kinetics and kinematics), pain and physical function scores. Regression models were used to control the influence of other parameters such as pain, age, gender, severity, walking speed, mass and height.
Results: No relationship was found of hip abductor strength with peak of external knee adduction moment and knee adduction angular impulse. Hip abductor strength explained 17% of contralateral pelvic drop and 21% of hip adduction angle. In addition, hip abductor strength explained 4% and 1% of the variance in the WOMAC physical function score and 40 meter fast paced walk test, respectively.
Conclusion: Considering the relationship of hip abductor strength with contralateral pelvic drop and hip adduction angle, specific exercises might improve physical function and lower limb dynamic alignment during gait
The Quantum Nature of a Nuclear Phase Transition
In their ground states, atomic nuclei are quantum Fermi liquids. At finite
temperatures and low densities, these nuclei may undergo a phase change similar
to, but substantially different from, a classical liquid gas phase transition.
As in the classical case, temperature is the control parameter while density
and pressure are the conjugate variables. At variance with the classical case,
in the nucleus the difference between the proton and neutron concentrations
acts as an additional order parameter, for which the symmetry potential is the
conjugate variable. Different ratios of the neutron to proton concentrations
lead to different critical points for the phase transition. This is analogous
to the phase transitions occurring in He-He liquid mixtures. We
present experimental results which reveal the N/Z dependence of the phase
transition and discuss possible implications of these observations in terms of
the Landau Free Energy description of critical phenomena.Comment: 5 pages, 4 figure
Thermotomaculum hydrothermale gen. nov., sp. nov., a novel heterotrophic thermophile within the phylum Acidobacteria from a deep-sea hydrothermal vent chimney in the Southern Okinawa Trough
http://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt08-13/
Historia empresarial e historia del trabajo: del aislamiento a la colaboración
Editada en la Fundación Empresa PúblicaPublicad
Type I ULIRGs: Transition Stage from ULIRGs to QSOs
We examine whether the ultraluminous infrared galaxies that contain a type I
Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to
quasi-stellar objects (QSOs). To inspect this issue, we compare the black hole
(BH) mass, the bulge luminosity and the far infrared luminosity among type I
ULIRGs, QSOs and elliptical galaxies. As a result, we find the following
results; (1) The type I ULIRGs have systematically smaller BH masses in spite
of the comparable bulge luminosity relative to QSOs and elliptical galaxies.
(2) The far-infrared luminosity of most type I ULIRGs is larger than the
Eddington luminosity. We show that above results do not change significantly
for 3 type I ULIRGs that we can estimate the visual extinction from the column
density. Also, for all 8 type I ULIRGs, we investigate the effect of
uncertainties of BH mass measurments and our sample bias, so that it turns out
that our results do not alter even if we consider above two effects. In
addition, Anabuki (2004) revealed that their X-ray properties are similar to
those of the narrow line Seyfert 1 galaxies. These would indicate that active
galactic nuclei (AGNs) with a high mass accretion rate exist in the type I
ULIRGs. Based on all of these findings, we conclude that it would be a natural
interpretation that type I ULIRGs are the early phase of BH growth, namely the
missing link between ULIRGs and QSOs. Moreover, by comparing our results with a
theoretical model of a coevolution scenario of a QSO BH and a galactic bulge,
we show clearly that this explanation would be valid.Comment: 11 pages, 4 figures, 4 tables accepted for publication in Ap
Survival of the mm-cm size grain population observed in protoplanetary disks
Millimeter interferometry provides evidence for the presence of mm to cm size
"pebbles" in the outer parts of disks around pre-main-sequence stars. The
observations suggest that large grains are produced relatively early in disk
evolution (< 1 Myr) and remain at large radii for longer periods of time (5 to
10 Myr). Simple theoretical estimates of the radial drift time of solid
particles, however, imply that they would drift inward over a time scale of
less than 0.1 Myr. In this paper, we address this conflict between theory and
observation, using more detailed theoretical models, including the effects of
sedimentation, collective drag forces and turbulent viscosity. We find that,
although these effects slow down the radial drift of the dust particles, this
reduction is not sufficient to explain the observationally determined long
survival time of mm/cm-sized grains in protoplanetary disks. However, if for
some reason the gas to dust ratio in the disk is reduced by at least a factor
of 20 from the canonical value of 100 (for instance through photoevaporation of
the gas), then the radial drift time scales become sufficiently large to be in
agreement with observations.Comment: Accepted for publication in Astronomy and Astrophysic
Measurements of the \gamma * p --> \Delta(1232) reaction at low Q2
We report new p measurements in the
resonance at the low momentum transfer region utilizing the
magnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud
dynamics are predicted to be dominant and appreciably changing in this region
while the momentum transfer is sufficiently low to be able to test chiral
effective calculations. The results disagree with predictions of constituent
quark models and are in reasonable agreement with dynamical calculations with
pion cloud effects, chiral effective field theory and lattice calculations. The
reported measurements suggest that improvement is required to the theoretical
calculations and provide valuable input that will allow their refinements
Trapping Solids at the Inner Edge of the Dead Zone: 3-D Global MHD Simulations
The poorly-ionized interior of the protoplanetary disk is the location where
dust coagulation processes may be most efficient. However even here,
planetesimal formation may be limited by the loss of solid material through
radial drift, and by collisional fragmentation of the particles. Our aim is to
investigate the possibility that solid particles are trapped at local pressure
maxima in the dynamically evolving disk. We perform the first 3-D global
non-ideal MHD calculations of the disk treating the turbulence driven by the
magneto-rotational instability. The domain contains an inner MRI-active region
near the young star and an outer midplane dead zone, with the transition
between the two modeled by a sharp increase in the magnetic diffusivity. The
azimuthal magnetic fields generated in the active zone oscillate over time,
changing sign about every 150 years. We thus observe the radial structure of
the `butterfly pattern' seen previously in local shearing-box simulations. The
mean magnetic field diffuses from the active zone into the dead zone, where the
Reynolds stress nevertheless dominates. The greater total accretion stress in
the active zone leads to a net reduction in the surface density, so that after
800 years an approximate steady state is reached in which a local radial
maximum in the midplane pressure lies near the transition radius. We also
observe the formation of density ridges within the active zone. The dead zone
in our models possesses a mean magnetic field, significant Reynolds stresses
and a steady local pressure maximum at the inner edge, where the outward
migration of planetary embryos and the efficient trapping of solid material are
possible.Comment: 17 pages, 30 *.ps files for figures. Accepted 16 November 2009 in A&
Lowest Q^2 Measurement of the gamma*p -> Delta Reaction: Probing the Pionic Contribution
To determine nonspherical angular momentum amplitudes in hadrons at long
ranges (low Q^2), data were taken for the p(\vec{e},e'p)\pi^0 reaction in the
Delta region at Q^2=0.060 (GeV/c)^2 utilizing the magnetic spectrometers of the
A1 Collaboration at MAMI. The results for the dominant transition magnetic
dipole amplitude and the quadrupole to dipole ratios at W=1232 MeV are:
M_{1+}^{3/2} = (40.33 +/- 0.63_{stat+syst} +/- 0.61_{model})
(10^{-3}/m_{\pi^+}),Re(E_{1+}^{3/2}/M_{1+}^{3/2}) = (-2.28 +/- 0.29_{stat+syst}
+/- 0.20_{model})%, and Re(S_{1+}^{3/2}/M_{1+}^{3/2}) = (-4.81 +/-
0.27_{stat+syst} +/- 0.26_{model})%. These disagree with predictions of
constituent quark models but are in reasonable agreement with lattice
calculations with non-linear (chiral) pion mass extrapolations, with chiral
effective field theory, and with dynamical models with pion cloud effects.
These results confirm the dominance, and general Q^2 variation, of the pionic
contribution at large distances.Comment: 6 pages, 3 figures, 1 tabl
The relationship between urinary C-Telopeptide fragments of type II collagen, knee joint load, pain, and physical function in individuals with medial knee osteoarthritis
Objective: Considering the osteoarthritis (OA) model that integrates the biological, mechanical, and structural components of the disease, the present study aimed to investigate the association between urinary C-Telopeptide fragments of type II collagen (uCTX-II), knee joint moments, pain, and physical function in individuals with medial knee OA. Methods: Twenty-five subjects radiographically diagnosed with knee OA were recruited. Participants were evaluated through three-dimensional gait analysis, uCTX-II level, the WOMAC pain and physical function scores, and the 40m walk test. The association between these variables was investigated using Pearson´s product-moment correlation, followed by a hierarchical linear regression, controlled by OA severity and body mass index (BMI). Results: No relationship was found between uCTX-II level and knee moments. A significant correlation between uCTX-II level and pain, physical function, and the 40m walk test was found. The hierarchical linear regression controlling for OA severity and BMI showed that uCTX-II level explained 9% of the WOMAC pain score, 27% of the WOMAC physical function score, and 7% of the 40m walk test. Conclusion: Greater uCTX-II level is associated with higher pain and reduced physical function and 40m walk test performance in individuals with medial knee OA
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