19,820 research outputs found
Analysis of data processing systems
Mathematical simulation models and software monitoring of multiprogramming computer syste
Two-dimensional matrix algorithm using detrended fluctuation analysis to distinguish Burkitt and diffuse large B-cell lymphoma
Copyright © 2012 Rong-Guan Yeh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.A detrended fluctuation analysis (DFA) method is applied to image analysis. The 2-dimensional (2D) DFA algorithms is proposed
for recharacterizing images of lymph sections. Due to Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL), there
is a significant different 5-year survival rates after multiagent chemotherapy. Therefore, distinguishing the difference between BL
and DLBCL is very important. In this study, eighteen BL images were classified as group A, which have one to five cytogenetic
changes. Ten BL images were classified as group B, which have more than five cytogenetic changes. Both groups A and B BLs are
aggressive lymphomas, which grow very fast and require more intensive chemotherapy. Finally, ten DLBCL images were classified
as group C. The short-term correlation exponent α1 values of DFA of groups A, B, and C were 0.370 ± 0.033, 0.382 ± 0.022, and
0.435 ± 0.053, respectively. It was found that α1 value of BL image was significantly lower (P < 0.05) than DLBCL. However, there
is no difference between the groups A and B BLs. Hence, it can be concluded that α1 value based on DFA statistics concept can
clearly distinguish BL and DLBCL image.National Science Council (NSC) of Taiwan the Center for Dynamical Biomarkers and
Translational Medicine, National Central University, Taiwan (also sponsored by National Science Council)
Interfacial strain in AlxGa1–xAs layers on GaAs
Detailed analysis of x-ray rocking curves was used to determine the depth profile of strain and composition in a 2500-Å-thick layer of AlxGa1–xAs grown by metalorganic chemical vapor deposition on 100 GaAs. The x value and layer thickness were in good agreement with the values expected from growth parameters. The presence of a transition region, 280 Å thick, was detected by the rocking curve. In this region, the Al concentration varies smoothly from 0 to 0.87. Measurement and control of the sharpness of such interfaces has important implications for heterojunction devices
Planar immersion lens with metasurfaces
The solid immersion lens is a powerful optical tool that allows light
entering material from air or vacuum to focus to a spot much smaller than the
free-space wavelength. Conventionally, however, they rely on semispherical
topographies and are non-planar and bulky, which limits their integration in
many applications. Recently, there has been considerable interest in using
planar structures, referred to as metasurfaces, to construct flat optical
components for manipulating light in unusual ways. Here, we propose and
demonstrate the concept of a planar immersion lens based on metasurfaces. The
resulting planar device, when placed near an interface between air and
dielectric material, can focus electromagnetic radiation incident from air to a
spot in material smaller than the free-space wavelength. As an experimental
demonstration, we fabricate an ultrathin and flexible microwave lens and
further show that it achieves wireless energy transfer in material mimicking
biological tissue
Average and worst-case specifications of precipitating auroral electron environment
The precipitation electrons in the auroral environment are highly variable in their energy and intensity in both space and time. As such they are a source of potential hazard to the operation of the Space Shuttle and other large spacecraft operating in polar orbit. In order to assess these hazards both the average and extreme states of the precipitating electrons must be determined. Work aimed at such a specification is presented. First results of a global study of the average characteristics are presented. In this study the high latitude region was divided into spatial elements in magnetic local time and corrected geomagnetic latitude. The average electron spectrum was then determined in each spatial element for seven different levels of activity as measured by K sub p using an extremely large data set of auroral observations. Second a case study of an extreme auroral electron environment is presented, in which the electrons are accelerated through field aligned potential as high as 30,000 volts and in which the spacecraft is seen to charge negatively to a potential approaching .5 kilovolts
Not Just a Theory—The Utility of Mathematical Models in Evolutionary Biology
Models have made numerous contributions to evolutionary biology, but misunderstandings persist regarding their purpose. By formally testing the logic of verbal hypotheses, proof-of-concept models clarify thinking, uncover hidden assumptions, and spur new directions of study. thumbnail image credit: modified from the Biodiversity Heritage Librar
Resolution enhancement of multichannel microwave imagery from the Nimbus-7 SMMR for maritime rainfall analysis
A restoration of the 37, 21, 18, 10.7, and 6.6 GHz satellite imagery from the scanning multichannel microwave radiometer (SMMR) aboard Nimbus-7 to 22.2 km resolution is attempted using a deconvolution method based upon nonlinear programming. The images are deconvolved with and without the aid of prescribed constraints, which force the processed image to abide by partial a priori knowledge of the high-resolution result. The restored microwave imagery may be utilized to examined the distribution of precipitating liquid water in marine rain systems
Complete bandgaps in one-dimensional left-handed periodic structures
Artificially fabricated structures with periodically modulated parameters
such as photonic crystals offer novel ways of controlling the flow of light due
to the existence of a range of forbidden frequencies associated with a photonic
bandgap. It is believed that modulation of the refractive index in all three
spatial dimensions is required to open a complete bandgap and prevent the
propagation of electromagnetic waves in all directions. Here we reveal that, in
a sharp contrast to what was known before and contrary to the accepted physical
intuition, a one-dimensional periodic structure containing the layers of
transparent left-handed (or negative-index) metamaterial can trap light in
three-dimensional space due to the existence of a complete bandgap.Comment: 4 pages, 5 figure
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