3,398 research outputs found
Treatment of the low bone mineral density with intravenous pamidronate in pediatric patients: review of a protocol of a single-day infusion twice a year
Exponential dynamical localization for the almost Mathieu operator
We prove that the exponential moments of the position operator stay bounded
for the supercritical almost Mathieu operator with Diophantine frequency
Catastrophic wear in a metal-on-ceramic total hip arthroplasty
A 51-year-old woman came to our clinic 6 months after a right total hip
arthroplasty. She had noticed a slowly growing mass in the proximal thigh and
referred progressive pain in the right groin. Plain radiography revealed
premature acetabular cup aseptic loosening, and in the computed tomography study,
a 14-cm-diameter mass was observed. Revision surgery was performed, showing a
metal-on-ceramic bearing surface. The histologic analysis of surrounding tissues
was reported as massive metallosis. Although occasionally chosen for primary or
revision hip arthroplasty, there is little information available about the in
vivo wear behavior of this combination. This important fact should be taken into
account before considering such a surface alternativ
Treatment of osteogenesis imperfecta with intravenous pamidronate in pediatric patients: comparison between a single-day infusion twice a year protocol with other regimens described in the literature
Upper bounds on wavepacket spreading for random Jacobi matrices
A method is presented for proving upper bounds on the moments of the position
operator when the dynamics of quantum wavepackets is governed by a random
(possibly correlated) Jacobi matrix. As an application, one obtains sharp upper
bounds on the diffusion exponents for random polymer models, coinciding with
the lower bounds obtained in a prior work. The second application is an
elementary argument (not using multiscale analysis or the Aizenman-Molchanov
method) showing that under the condition of uniformly positive Lyapunov
exponents, the moments of the position operator grow at most logarithmically in
time.Comment: final version, to appear in CM
VORTEX FORMATION IN INCOMPRESSIBLE AXISYMMETRIC FREE JETS
Free jets have been utilized extensively in many industrial applications. In general jet fluid discharging from a nozzle develops flow oscillations in the shear layer. The oscillations will roll up to eventually become toroidal vortices which increase in size with the axial distance from the nozzle. In the present work, flow visualization as well as hot-film anemometry have been employed in order to study incompressible axisymmetric free jet in moderate Reynolds numbers up to 20,000. The injection of liquid dye or micro particles associated with a laser sheet turns possible to visualize the shear layers and, consequently, the vortex formation. Hot-film measurements into the jet allow determining the flow velocity profile. Flow visualization is a qualitative tool which a broad view of the flow topology. On the other hand, hot-film anemometry is a precise quantitative tool but measurement in only one location at a time. The association of flow visualization and hot-film anemometry shows very adequate for free jet studies
New records of recently described chemosymbiotic bivalves for mud volcanoes within the European waters (Gulf of Cádiz)
Chemosymbiotic bivalves are important members of cold seep communities and information on their distribution in theEuropean waters is still quite scarce. This study reports the presence of living populations and shell remains of some recently described bivalves such as Lucinoma asapheus, Solemya elarraichensis and Acharax gadirae as well as Bathymodiolus sp. in the mud volcanoes of the Spanish Atlantic waters. Living populations of these species were thus far only found in Anastasya, Aveiro and Almazán mud volcanoes, together with other chemosymbiotic metazoa (Siboglinum spp.), suggesting the presence of moderate seepage activity. In other mud volcanoes (Albolote, Gazul), the benthic communities are dominated by sessile filter feeders on authigenic carbonates (chimneys, slabs) and only the shell remains of some chemosymbiotic bivalves were found, indicating earlier or very low seepage conditions. The present study elaborates on the known distribution of L. asapheus and S. elarraichensis to the European waters of the Gulf of Cádiz
Spectral and Localization Properties for the One-Dimensional Bernoulli Discrete Dirac Operator
A 1D Dirac tight-binding model is considered and it is shown that its
nonrelativistic limit is the 1D discrete Schr?odinger model. For random
Bernoulli potentials taking two values (without correlations), for typical
realizations and for all values of the mass, it is shown that its spectrum is
pure point, whereas the zero mass case presents dynamical delocalization for
specific values of the energy. The massive case presents dynamical localization
(excluding some particular values of the energy). Finally, for general
potentials the dynamical moments for distinct masses are compared, especially
the massless and massive Bernoulli cases.Comment: no figure; 24 pages; to appear in Journal of Mathematical Physic
Diversity among smallholder farms and households—Consequences for trade-offs, trajectories, targeting and scaling
United States Agency for International Developmen
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