1,055 research outputs found
Design and development of a multi-layer memory system Final report, 28 Jan. 1966 - 27 Jan. 1967
Design and development of multilayer memory syste
Morphological Evolution of Distant Galaxies from Adaptive Optics Imaging
We report here on a sample of resolved, infrared images of galaxies at z~0.5
taken with the 10-m Keck Telescope's Adaptive Optics (AO) system. We regularly
achieve a spatial resolution of 0.05'' and are thus able to resolve both the
disk and bulge components. We have extracted morphological information for ten
galaxies and compared their properties to those of a local sample. The
selection effects of both samples were explicitly taken into account in order
to derive the unbiased result that disks at z~0.5 are ~0.6 mag arcsec^-2
brighter than, and about the same size as, local disks. The
no-luminosity-evolution case is ruled out at 90% confidence. We also find, in a
more qualitative analysis, that the bulges of these galaxies have undergone a
smaller amount of surface brightness evolution and have also not changed
significantly in size from z~0.5 to today. This is the first time this type of
morphological evolution has been measured in the infrared and it points to the
unique power of AO in exploring galaxy evolution.Comment: 27 pages, 7figures, 2 tables. Accepted for publication in the
Astrophysical Journa
The influence of a new clinical motion for endodontic instruments on the incidence of postoperative pain
Previous studies showed that motor motions play an important role in determining apical extrusion of debris. Therefore a new clinical motion (MIMERACI) has been proposed. The basic idea is to progress slowly (1mm advancement), and after each 1mm, to remove the instrument from the canal, clean flutes and irrigate. The aim of the study was to prove whether the clinical use of MIMERACI technique would influence or not postoperative pain.MATERIALS AND METHODS:
100 teeth requesting endodontic treatment were selected for the study and divided into two similar groups based on anatomy, pre-operative symptoms and vitality, presence or absence of periapical lesion. All teeth were shaped, cleaned and obturated by the same operator, using the same NiTi instruments. The only difference between the two groups was the instrumentation technique: tradional (group A) vs MIMERACI (group B). Assessment of postoperative pain was performed 3 days after treatment. Presence, absence and degree of pain were recorded with a visual analogue scale (VAS), validated in previous studies. Collected data statistically analyzed using one-way ANOVA post hoc Tukey test.
RESULTS:
For VAS pain scores MIMERACI technique showed significantly better results than group A (p=0,031). Overall, both incidence and intensity of symptoms were significantly lower. Flare ups occurred in 3 patients, but none treated with the MIMERACI Technique.
CONCLUSIONS:
Since extruded debris can elicit more postoperative pain, results obtained by using MIMERACI technique are probably due to many factors: better mechanical removal and less production of debris and more efficient irrigation during instrumentation
Exploring the Structure of Distant Galaxies with Adaptive Optics on the Keck-II Telescope
We report on the first observation of cosmologically distant field galaxies
with an high order Adaptive Optics (AO) system on an 8-10 meter class
telescope. Two galaxies were observed at 1.6 microns at an angular resolution
as high as 50 milliarcsec using the AO system on the Keck-II telescope. Radial
profiles of both objects are consistent with those of local spiral galaxies and
are decomposed into a classic exponential disk and a central bulge. A
star-forming cluster or companion galaxy as well as a compact core are detected
in one of the galaxies at a redshift of 0.37+/-0.05. We discuss possible
explanations for the core including a small bulge, a nuclear starburst, or an
active nucleus. The same galaxy shows a peak disk surface brightness that is
brighter than local disks of comparable size. These observations demonstrate
the power of AO to reveal details of the morphology of distant faint galaxies
and to explore galaxy evolution.Comment: 5 pages, Latex, 3 figures. Accepted for publication in P.A.S.
Utilization trends of pedicle subtraction osteotomies compared to posterior spinal fusion for deformity: A national database analysis between 2008–2011
BACKGROUND: Increased awareness regarding the importance of the sagittal spinal profile has led to more aggressive correction of sagittal malalignment. The utilization trends of pedicle subtraction osteotomy (PSO) for sagittal plane correction in spinal deformity surgery have not been well characterized. METHODS: A commercially available database (PearlDiver, Inc) was queried for both Private Payor and 5 % Medicare claims from 2008 to 2011. Revision and clarification of the coding guidelines for PSO were introduced in 2008. Patients who had a thoracic and/or lumbar PSO were identified using CPT codes (22206-22208). In order to appropriately interpret trends in PSO use, three comparison groups were identified. Patients who had a diagnosis of adult spine deformity were identified using ICD-9 codes. Patients who had fusion for spine deformity or posterior spine fusion were identified using CPT codes. Differences in annual utilization and demographics between these four groups were then compared. RESULTS: From the Private Payor database, 199 PSOs were identified with the number of PSOs increasing from 33 in 2008, to 61 in 2011, representing a 185 % increase. From the Medicare data, 102 PSOs were identified, increasing from 13 in 2008 to 32 in 2011, a 246 % increase. In contrast, from both databases, there was minimal to no increase in the incidence of adult spine deformity, fusion for spine deformity or posterior spine fusion over the study time interval. CONCLUSION: Over the study time interval, there was up to a 3.2-fold increase in the utilization of PSOs while the diagnosis of adult spine deformity, fusion for spine deformity and posterior spine fusions had minimal to no increase
Quantum Magnetic Deflagration in Mn12 Acetate
We report controlled ignition of magnetization reversal avalanches by surface
acoustic waves in a single crystal of Mn12 acetate. Our data show that the
speed of the avalanche exhibits maxima on the magnetic field at the tunneling
resonances of Mn12. Combined with the evidence of magnetic deflagration in Mn12
acetate (Suzuki et al., cond-mat/0506569) this suggests a novel physical
phenomenon: deflagration assisted by quantum tunneling.Comment: 4 figure
Propagation of Avalanches in Mn-acetate: Magnetic Deflagration
Local time-resolved measurements of fast reversal of the magnetization of
single crystals of Mn12-acetate indicate that the magnetization avalanche
spreads as a narrow interface that propagates through the crystal at a constant
velocity that is roughly two orders of magnitude smaller than the speed of
sound. We argue that this phenomenon is closely analogous to the propagation of
a flame front (deflagration) through a flammable chemical substance.Comment: 5 pages, 5 figure
Intermediate oncologic outcomes after uniportal video-assisted thoracoscopic thymectomy for early-stage thymoma
Anisotropic magnetic deflagration in single crystals of Gd5Ge4
Experimental evidence of the anisotropy of the magnetic deflagration
associated with the low-temperature first order antiferromagnetic (AFM) -->
ferromagnetic (FM) phase-transition in single crystals of Gd5Ge4 is reported.
The deflagrations have been induced by controlled pulses of surface acoustic
waves (SAW) allowing us to explore both the magnetic field and temperature
dependencies on the characteristic times of the phenomenon. The study was done
using samples with different geometries and configurations between the SAW
pulses and the direction of the applied magnetic field with respect to the
three main crystallographic directions of the samples. The effect of
temperature is nearly negligible, whereas observed strong magnetic field
dependence correlates with the magnetic anisotropy of the sample. Finally, the
role of the SAW pulses in both the ignition and formation of the deflagration
front was also studied, and we show that the thermal diffusivity of Gd5Ge4 must
be anisotropic, following \kappaa>\kappab>\kappac.Comment: 10 pages, 4 figure
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