Radar multipath scattering from the composite model: Specular image modified model and ISAR imaging analysis

2019 ◽  
Vol 29 (12) ◽  
Author(s):  
Bin Chen ◽  
Chuangming Tong
Keyword(s):  
Composite Model ◽  
Imaging Analysis ◽  
Modified Model ◽  
Isar Imaging ◽  
Multipath Scattering ◽  
Specular Image

Bifurcation in a Simple Model of the Cardiovascular System

2000 ◽  
Vol 39 (02) ◽  
pp. 118-121 ◽  
Author(s):  
S. Akselrod ◽  
S. Eyal
Keyword(s):  
Nonlinear Dynamics ◽  
Blood Pressure ◽  
Heart Rate ◽  
Fixed Point ◽  
Cardiovascular System ◽  
Modified Model ◽  
Mayer Waves ◽  
Sustained Oscillations ◽  
Human Cardiovascular System ◽  
Physiological Values

Abstract:A simple nonlinear beat-to-beat model of the human cardiovascular system has been studied. The model, introduced by DeBoer et al. was a simplified linearized version. We present a modified model which allows to investigate the nonlinear dynamics of the cardiovascular system. We found that an increase in the -sympathetic gain, via a Hopf bifurcation, leads to sustained oscillations both in heart rate and blood pressure variables at about 0.1 Hz (Mayer waves). Similar oscillations were observed when increasing the -sympathetic gain or decreasing the vagal gain. Further changes of the gains, even beyond reasonable physiological values, did not reveal another bifurcation. The dynamics observed were thus either fixed point or limit cycle. Introducing respiration into the model showed entrainment between the respiration frequency and the Mayer waves.

Multilocus Analysis of Genetic Susceptibility to Myocardial Infarction in Russians: Replication Study

Acta Naturae ◽  
2017 ◽  
Vol 9 (4) ◽  
pp. 74-83
Author(s):  
N. G. Kukava ◽  
B. V. Titov ◽  
G. J. Osmak ◽  
N. A. Matveeva ◽  
O. G. Kulakova ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Genetic Markers ◽  
Prognostic Significance ◽  
Cumulative Effect ◽  
Mthfr Gene ◽  
Composite Model ◽  
Replication Study ◽  
Epistatic Interactions ◽  
Multilocus Analysis ◽  
Lipid Metabolism Genes

In search of genetic markers of myocardial infarction (MI) risk, which have prognostic significance for Russians, we performed a replication study of MI association with genetic variants of PCSK9 (rs562556), APOE (epsilon polymorphism, rs7412 and rs429358), LPL (rs320), MTHFR (rs1801133), eNOS (rs2070744), and the 9p21 region (rs1333049) in 405 patients with MI and 198 controls. Significant MI association was observed with variants of the lipid metabolism genes (PCSK9, APOE and LPL), and of eNOS. The SNPs in the MTHFR gene and the 9p21 region were not significantly associated with MI one by one but were included in several different MI-associated allelic combinations identified by multilocus analysis. Since we have not revealed nonlinear epistatic interactions between the components of the identified combinations, we postulate that the cumulative effect of genes that form a combination arises from the summation of their small independent contributions. The prognostic significance of the additive composite model built from the PCSK9, APOE, LPL, and eNOS genes as genetic markers was assessed using ROC analysis. After we included these markers in the previously published composite model of individual genetic risk of MI, the prognostic efficacy in our sample reached AUC = 0.676. However, the results obtained in this study certainly need to be replicated in an independent sample of Russians.

Imaging Analysis of Colonic Villous Tumors

1996 ◽  
Vol 34 (2) ◽  
pp. 239
Author(s):  
Choon Hyeong Lee ◽  
Ik Yang ◽  
Joo Won Lim ◽  
Dong Ho Lee ◽  
Yung Tae Ko
Keyword(s):  
Imaging Analysis ◽  
Villous Tumors
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