515 research outputs found
A Lethal Combination That Cannot be Ignored: President Clinton and National Health Insurance
President Clinton started a historic effort to find an acceptable new balance of competing public demands, to reinvent health care in ways that provide somewhat less freedom for patients and doctors and somewhat more cost control. In its mind-boggling complexity, the debate is whether his program or any of its rivals can do what they claim
Beyond backscattering: Optical neuroimaging by BRAD
Optical coherence tomography (OCT) is a powerful technology for rapid
volumetric imaging in biomedicine. The bright field imaging approach of
conventional OCT systems is based on the detection of directly backscattered
light, thereby waiving the wealth of information contained in the angular
scattering distribution. Here we demonstrate that the unique features of
few-mode fibers (FMF) enable simultaneous bright and dark field (BRAD) imaging
for OCT. As backscattered light is picked up by the different modes of a FMF
depending upon the angular scattering pattern, we obtain access to the
directional scattering signatures of different tissues by decoupling
illumination and detection paths. We exploit the distinct modal propagation
properties of the FMF in concert with the long coherence lengths provided by
modern wavelength-swept lasers to achieve multiplexing of the different modal
responses into a combined OCT tomogram. We demonstrate BRAD sensing for
distinguishing differently sized microparticles and showcase the performance of
BRAD-OCT imaging with enhanced contrast for ex vivo tumorous tissue in
glioblastoma and neuritic plaques in Alzheimer's disease
An evaluation of the testing procedures used in teaching American history.
Mounted forms, p. I-XI, at end.
Typewritten sheets in cover.
Thesis (M.A.)--Boston University
"Selected bibliography:" p. 138-140
Rapid placement and anatomical sculpting of hardened posterior composite
Posterior composites have long had a reputation for being difficult and time consuming in clinical practice. In addition to this reputation, it has been noted that recurrent caries and in general failure of these restorations prematurely has been a problem. Relative to amalgams, posterior composites have vexed even good clinical dentist. This video presentation illustrates techniques that not only save time but also create more predictable high-quality restorations
Conjugate Product Graphs for Globally Optimal 2D-3D Shape Matching
We consider the problem of finding a continuous and non-rigid matching
between a 2D contour and a 3D mesh. While such problems can be solved to global
optimality by finding a shortest path in the product graph between both shapes,
existing solutions heavily rely on unrealistic prior assumptions to avoid
degenerate solutions (e.g. knowledge to which region of the 3D shape each point
of the 2D contour is matched). To address this, we propose a novel 2D-3D shape
matching formalism based on the conjugate product graph between the 2D contour
and the 3D shape. Doing so allows us for the first time to consider
higher-order costs, i.e. defined for edge chains, as opposed to costs defined
for single edges. This offers substantially more flexibility, which we utilise
to incorporate a local rigidity prior. By doing so, we effectively circumvent
degenerate solutions and thereby obtain smoother and more realistic matchings,
even when using only a one-dimensional feature descriptor. Overall, our method
finds globally optimal and continuous 2D-3D matchings, has the same asymptotic
complexity as previous solutions, produces state-of-the-art results for shape
matching and is even capable of matching partial shapes
Shear Bond Strength of Nine Dual Cured Build-Up Materials and a Light-Curing Adhesive System on Dentin
The purpose of this study was to measure the shear bond strength of nine different commercially available dual cured core build-up materials on human dentin in conjunction with a light curing adhesive system. The null hypothesis was that there is no statistical significant difference among the core build-up systems
Forecast Combinations in R using the ForecastComb Package
This paper introduces the R package ForecastComb. The aim is to provide researchers and practitioners with a comprehensive implementation of the most common ways in which forecasts can be combined. The package in its current version covers 15 popular estimation methods for creating a combined forecasts – including simple methods, regression-based methods, and eigenvector-based methods. It also includes useful tools to deal with common challenges of forecast combination (e.g., missing values in component forecasts, or multicollinearity), and to rationalize and visualize the combination results
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