Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Detection Of Variable Frequency Signals Using A Fast Chirp Transform, F. A. Jenet, T. A. Prince
Detection Of Variable Frequency Signals Using A Fast Chirp Transform, F. A. Jenet, T. A. Prince
Physics and Astronomy Faculty Publications and Presentations
The detection of signals with varying frequency is important in many areas of physics and astrophysics. The current work was motivated by a desire to detect gravitational waves from the binary inspirai of neutron stars and black holes, a topic of significant interest for the new generation of interferometric gravitational wave detectors such as LIGO. However, this work has significant generality beyond gravitational wave signal detection. We define a fast chirp transform (FCT) analogous to the fast Fourier transform. Use of the FCT provides a simple and powerful formalism for detection of signals with variable frequency just as Fourier transform …
P-Selectin Or Intercellular Adhesion Molecule (Icam)-1 Deficiency Substantially Protects Against Atherosclerosis In Apolipoprotein E-Deficient Mice, Robert G. Collins, Rizwan Velji, Natalia V. Guevara, M. John Hicks, Lawrence Chan, Arthur L. Beaudet
P-Selectin Or Intercellular Adhesion Molecule (Icam)-1 Deficiency Substantially Protects Against Atherosclerosis In Apolipoprotein E-Deficient Mice, Robert G. Collins, Rizwan Velji, Natalia V. Guevara, M. John Hicks, Lawrence Chan, Arthur L. Beaudet
Physics and Astronomy Faculty Publications and Presentations
The expression of leukocyte and endothelial cell adhesion molecules (CAMs) is essential for the emigration of leukocytes during an inflammatory response. The importance of the inflammatory response in the development of atherosclerosis is indicated by the increased expression of adhesion molecules, proinflammatory cytokines, and growth factors in lesions and lesion-prone areas and by protection in mice deficient in various aspects of the inflammatory response. We have quantitated the effect of deficiency for intercellular adhesion molecule (ICAM)-1, P-selectin, or E-selectin on atherosclerotic lesion formation at 20 wk of age in apolipoprotein (apo) E(- /-) (deficient) mice fed a normal chow diet. …
Critical Adsorption On Defects In Ising Magnets And Binary Alloys, Andreas Hanke
Critical Adsorption On Defects In Ising Magnets And Binary Alloys, Andreas Hanke
Physics and Astronomy Faculty Publications and Presentations
Long-range correlations in a magnet close to its critical point or in a binary alloy close to a continuous order-disorder transition can substantially enhance the effect of local perturbations. It is demonstrated using a position-space renormalization procedure that quasi-one-dimensional defects which break the symmetry of the order parameter have pronounced effects: They cause long-range critical adsorption profiles and give rise to new universal critical exponents, which are identified and calculated using field-theoretical methods.
The Hî² Index As An Age Indicator Of Old Stellar Systems: The Effects Of Horizontal-Branch Stars, Hyun Chul Lee, Suk Jin Yoon, Young Wook Lee
The Hî² Index As An Age Indicator Of Old Stellar Systems: The Effects Of Horizontal-Branch Stars, Hyun Chul Lee, Suk Jin Yoon, Young Wook Lee
Physics and Astronomy Faculty Publications and Presentations
The strength of the Hβ index is computed for the integrated spectra of model globular clusters from the evolutionary population synthesis. For the first time, these models take into account the detailed systematic variation of horizontal-branch (HB) morphology with age and metallicity. Our models show that the Hβ index is significantly affected by the presence of blue HB stars. Because of the contribution from blue HB stars, the Hβ does not monotonically decrease as metallicity increases at a given age. Instead, it reaches a maximum strength when the distribution of HB stars is centered around 9500 K, the temperature at …
Robust Test For Detecting Nonstationarity In Data From Gravitational Wave Detectors, Soumya Mohanty
Robust Test For Detecting Nonstationarity In Data From Gravitational Wave Detectors, Soumya Mohanty
Physics and Astronomy Faculty Publications and Presentations
It is difficult to choose detection thresholds for tests of nonstationarity that assume a priori a noise model if the data are statistically uncharacterized to begin with. This is a potentially serious problem when an automated analysis is required, as would be the case for the huge data sets that large interferometric gravitational wave detectors will produce. A solution is proposed in the form of a robust time-frequency test for detecting nonstationarity whose threshold for a specified false alarm rate is almost independent of the statistical nature of the ambient stationary noise. The efficiency of this test in detecting bursts …