9,327 research outputs found
1995 atmospheric trace molecule spectroscopy (ATMOS) linelist
The Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment uses a Fourier-transform spectrometer on board the Space Shuttle to record infrared solar occultation spectra of the atmosphere at 0.01-cm^(-1) resolution. The current version of the molecular spectroscopic database used for the analysis of the data obtained during three Space Shuttle missions between 1992 and 1994 is described. It is an extension of the effort first described by Brown et al. [Appl. Opt. 26, 5154 (1987)] to maintain an up-to-date database for the ATMOS experiment. The three-part ATMOS compilation contains Line parameters of 49 molecular species between 0 and 10000 cm^(-1), The main list, with nearly 700,000 entries, is an updated version of the HITRAN 1992 database. The second compilation contains supplemental line parameters, and the third set consists of absorption cross sections to represent the unresolvable features of heavy molecules. The differences between the ATMOS database and other public compilations are discussed
Propellant material compatibility program and results
The effects of long-term (up to 10 years) contact of inert materials with earth-storable propellants were studied for the purpose of designing chemical propulsion system components that can be used for current as well as future planetary spacecraft. The primary experimental work, and results to date are reported. Investigations include the following propellants: hydrazine, hydrazine-hydrazine nitrate blends, monomethyl-hydrazine, and nitrogen tetroxide. Materials include: aluminum alloys, corrosion-resistant steels, and titanium alloys. More than 700 test specimen capsules were placed in long-term storage testing at 43 C in the special material compatibility facility. Material ratings relative to the 10-year requirement have been assigned
Two point correlations of a trapped interacting Bose gas at finite temperature
We develop a computationally tractable method for calculating correlation
functions of the finite temperature trapped Bose gas that includes the effects
of s-wave interactions. Our approach uses a classical field method to model the
low energy modes and treats the high energy modes using a Hartree-Fock
description. We present results of first and second order correlation
functions, in position and momentum space, for an experimentally realistic
system in the temperature range of to . We also characterize
the spatial coherence length of the system. Our theory should be applicable in
the critical region where experiments are now able to measure first and second
order correlations.Comment: 9 pages, 4 figure
L^{2}-restriction bounds for eigenfunctions along curves in the quantum completely integrable case
We show that for a quantum completely integrable system in two dimensions,the
-normalized joint eigenfunctions of the commuting semiclassical
pseudodifferential operators satisfy restriction bounds ofthe form for generic
curves on the surface. We also prove that the maximal restriction
bounds of Burq-Gerard-Tzvetkov are always attained for certain exceptional
subsequences of eigenfunctions.Comment: Correct some typos and added some more detail in section
Quick Annotator: an open-source digital pathology based rapid image annotation tool.
Image-based biomarker discovery typically requires accurate segmentation of histologic structures (e.g. cell nuclei, tubules, and epithelial regions) in digital pathology whole slide images (WSIs). Unfortunately, annotating each structure of interest is laborious and often intractable even in moderately sized cohorts. Here, we present an open-source tool, Quick Annotator (QA), designed to improve annotation efficiency of histologic structures by orders of magnitude. While the user annotates regions of interest (ROIs) via an intuitive web interface, a deep learning (DL) model is concurrently optimized using these annotations and applied to the ROI. The user iteratively reviews DL results to either (1) accept accurately annotated regions or (2) correct erroneously segmented structures to improve subsequent model suggestions, before transitioning to other ROIs. We demonstrate the effectiveness of QA over comparable manual efforts via three use cases. These include annotating (1) 337,386 nuclei in 5 pancreatic WSIs, (2) 5,692 tubules in 10 colorectal WSIs, and (3) 14,187 regions of epithelium in 10 breast WSIs. Efficiency gains in terms of annotations per second of 102×, 9×, and 39× were, respectively, witnessed while retaining f-scores >0.95, suggesting that QA may be a valuable tool for efficiently fully annotating WSIs employed in downstream biomarker studies
Bioresorbable Polylactide Interbody Implants in an Ovine Anterior Cervical Discectomy and Fusion Model: Three-Year Results
Study Design.
In vivo study of anterior discectomy and fusion using a bioresorbable 70:30 poly(l-lactide-co-d,l-lactide) interbody implant in an ovine model.
Objective.
To evaluate the efficacy of the polylactide implant to function as an interbody fusion device, and to assess the tissue reaction to the material during the resorption process.
Summary of Background Data.
The use of polylactide as a cervical interbody implant has several potential advantages when compared with traditional materials. Having an elastic modulus very similar to bone minimizes the potential for stress shielding, and as the material resorbs additional loading is transferred to the developing fusion mass. Although preclinical and clinical studies have demonstrated the suitability of polylactide implants for lumbar interbody fusion, detailed information on cervical anterior cervical discectomy and fusion (ACDF) with polylactide devices is desirable.
Methods.
Single level ACDF was performed in 8 skeletally mature ewes. Bioresorbable 70:30 poly (l-lactide-co-d,l-lactide) interbody implants packed with autograft were used with single-level metallic plates. Radiographs were made every 3 months up to 1 year, and yearly thereafter. The animals were killed at 6 months (3 animals), 12 months (3 animals), and 36 months (2 animals). In addition to the serial plain radiographs, the specimens were evaluated by nondestructive biomechanical testing and undecalcified histologic analysis.
Results.
The bioresorbable polylactide implants were effective in achieving interbody fusion. The 6-month animals appeared fused radiographically and biomechanically, whereas histologic sections demonstrated partial fusion (in 3 of 3 animals). Radiographic fusion was confirmed histologically and biomechanically at 12 months (3 of 3 animals) and 36 months (2 of 2 animals). A mild chronic inflammatory response to the resorbing polylactide implant was observed at both 6 months and 12 months. At 36 months, the operative levels were solidly fused and the implants were completely resorbed. No adverse tissue response was observed in any animal at any time period.
Conclusion.
Interbody fusion was achieved using bioresorbable polylactide implants, with no evidence of implant collapse, extrusion, or adverse tissue response to the material. The use of polylactide as a cervical interbody device appears both safe and effective based on these ACDF animal model results
On polymorphic logical gates in sub-excitable chemical medium
In a sub-excitable light-sensitive Belousov-Zhabotinsky chemical medium an
asymmetric disturbance causes the formation of localized traveling
wave-fragments. Under the right conditions these wave-fragment can conserve
their shape and velocity vectors for extended time periods. The size and life
span of a fragment depend on the illumination level of the medium. When two or
more wave-fragments collide they annihilate or merge into a new wave-fragment.
In computer simulations based on the Oregonator model we demonstrate that the
outcomes of inter-fragment collisions can be controlled by varying the
illumination level applied to the medium. We interpret these wave-fragments as
values of Boolean variables and design collision-based polymorphic logical
gates. The gate implements operation XNOR for low illumination, and it acts as
NOR gate for high illumination. As a NOR gate is a universal gate then we are
able to demonstrate that a simulated light sensitive BZ medium exhibits
computational universality
The Peculiar Type Ia Supernova 1999by: Spectroscopy at Early Epochs
We present medium resolution (lambda/Delta lambda = 2500) optical
spectroscopy of SN 1999by in NGC 2841 made around its light maximum. The depth
ratio of the two Si II features at 5800 AA and 6150 AA being R(SiII) approx.
0.63 at maximum indicates that this SN belongs to the peculiar, sub-luminous
SNe Ia. Radial velocities inferred from the minimum of the 6150 AA trough
reveal a steeper decline of the velocity curve than expected for ``normal'' SNe
Ia, consistent with the behavior of published VRI light curves. A revised
absolute magnitude of SN 1999by and distance to its host galaxy NGC 2841 is
estimated based on the Multi-Color Light Curve Shape (MLCS) method, resulting
in M_V(max)=-18.06+/- 0.1 mag and d = 17.1+/-1.2 Mpc, respectively. An
approximative linear dependence of the luminosity parameter Delta on R(SiII) is
presented.Comment: accepted for publication in Astron. Journal (2001 June
- …