The local asymptotic minimax adaptive property of a recursive estimate

1988 ◽  
Vol 6 (6) ◽  
pp. 383-388 ◽  
Author(s):  
Václav Fabian
Keyword(s):  
Adaptive Property ◽  
Asymptotic Minimax ◽  
Recursive Estimate

scholarly journals Impact of cryopreservation on lipid composition of reproductive cells of male sterlets (Acipenser Ruthenus L.)

2018 ◽  
Vol 5 (1) ◽  
pp. 73-83
Author(s):  
L. Drahan ◽  
S. Veselsky ◽  
Yu. Rud ◽  
L. Buchatsky
Keyword(s):  
Lipid Composition ◽  
Low Temperatures ◽  
Neutral Lipids ◽  
Sperm Quality ◽  
Phospholipid Bilayer ◽  
Standard Equipment ◽  
Slowing Down ◽  
Acipenser Ruthenus ◽  
Adaptive Property ◽  
The Impact

Aim. To estimate the impact of low temperatures on the lipid composition of reproductive cells of male sterlets (Acipenser ruthenus L) in cryopreservation environment. Methods. The determination of sperm quality (color, consistence, concentration and motility of spermatozoa) was estimated by common biochemical methods using standard equipment. Thin-layer chromatography was used to reveal fi ve fractions of neutral lipids in the sperm of investigated fi sh, which were distributed on the plates as follows: the starting line demonstrated phospholipids, cholesterol, free fatty acids, triacylglycerol and ethers of cholesterol. The adaptive property of sperm was estimated by the level of spermatozoa survival prior to and after cryopreservation. Results. The obtained results of sterlet sperm activity prior to and after cryopreservation demonstrate high quality of native sperm and its considerable deterioration after freezing/thawing. Conclusions. The impact of low temperatures on the lipid composition of reproductive cells of male sterlets (Acipenser ruthenus L) in cryopreservation environment leads to impairments of the phospholipid bilayer of their membranes. It was established that during the thawing of frozen sperm cells which preserved their viability after cryopreservation their motility and capability of fertilizing an ovum were somewhat restored with slowing down of sperm cell motility.

scholarly journals Modernization of adaptive matching pursuit method to analyze geophysical signals of pulse nature

2018 ◽  
Vol 62 ◽  
pp. 02012 ◽  
Author(s):  
Ol’ga Lukovenkova ◽  
Yuriy Marapulets ◽  
Aleksandr Tristanov ◽  
Alina Kim
Keyword(s):  
Numerical Methods ◽  
Matching Pursuit ◽  
Sparse Approximation ◽  
Approximation Methods ◽  
Initial Signal ◽  
Gradient Direction ◽  
Adaptive Property ◽  
Matching Pursuit Algorithm ◽  
Electromagnetic Signals ◽  
Direction Search

The paper is devoted to the development and comparison of different numerical methods which increase the adaptive property and improve the accuracy of matching pursuit algorithm in connection to geoacoustic and electromagnetic signals. At each step of adaptive matching pursuit, a function is chosen which has the highest correlation with an initial signal. Then parameters of a chosen function are refined. The refinement is performed by the help of different grid methods and methods based on gradient direction search. The paper considers the peculiarities of application of sparse approximation methods to geophysical signals of pulse nature and compares different variants of modification of adaptive matching pursuit algorithm.

Difference in the Na affinity of Na(+)-K(+)-ATPase along the rabbit nephron: modulation by K

1990 ◽  
Vol 259 (2) ◽  
pp. F246-F250 ◽  
Author(s):  
C. Barlet-Bas ◽  
L. Cheval ◽  
C. Khadouri ◽  
S. Marsy ◽  
A. Doucet
Keyword(s):  
Atpase Activity ◽  
Thick Ascending Limb ◽  
Kidney Cells ◽  
Nephron Segments ◽  
Adaptive Property ◽  
Collecting Tubule ◽  
Pump Activity ◽  
K Concentration ◽  
Cortical Collecting Tubule

The sensitivity of Na(+)-K(+)-ATPase to Na was determined in single segments of rabbit nephron isolated by microdissection. In the cortical collecting tubule (CCT), Na(+)-K(+)-ATPase was threefold more sensitive to Na (apparent K0.5 approximately 3 mM) than in proximal convoluted tubule and cortical thick ascending limb (apparent K0.5 approximately 10 mM). Furthermore, increasing K concentration from 5 to greater than 100 mM markedly reduced the affinity of the pump for Na in all three nephron segments. In fact, the main shift in Na affinity occurred when K changed from 100 to 120 mM; in the CCT, increasing K concentration from 100 to 120 mM while maintaining Na concentration at 10 mM reduced Na(+)-K(+)-ATPase activity by greater than 35%. These findings confirm that, in kidney cells as in other cells, intracellular Na limits the rate of Na(+)-K(+)-ATPase. Thus any alteration of intracellular Na concentration modifies the pump activity in a way that contributes to the restoration of intracellular Na homeostasis. This adaptive property is particularly efficient in the collecting tubule in which the apparent K0.5 of the pump for Na is close to normal intracellular Na concentration. Furthermore, changes in intracellular K concentration, which usually accompany those of Na so as to maintain the total cation concentration constant, potentiate the regulatory role of Na through modifications of its affinity for the pump.

Theoretical analysis on the adaptive vibration attenuation of a fixed-fixed beam realized by a piezo-shape memory alloy ferrule

2019 ◽  
Vol 30 (14) ◽  
pp. 2079-2090 ◽  
Author(s):  
Longfei Wang ◽  
Ying Wu ◽  
Zishun Liu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Self Regulation ◽  
Nonlinear Dynamic Response ◽  
Adaptive Property ◽  
Proposed Model ◽  
Vibration Attenuation ◽  
The Stability ◽  
System Characteristics ◽  
Fixed Beam

In this article, the vibration attenuation of a fixed-fixed beam with a piezo-shape memory alloy ferrule is theoretically investigated. First, a dynamic model of the beam with a piezo-shape memory alloy ferrule is established, and the nonlinear dynamic response of the model is numerically analysed. The results show that the stability of the beam structure can be improved adaptively through self-regulation of the stiffness of the piezo-shape memory alloy ferrule undergoing external excitations. The effects of some internal system characteristics, such as the ferrule dimensions as well as the initial ferrule temperatures and boundary conditions, on the vibration attenuation of the beam are discussed. The stability of the proposed model under different external factors, including damping and external excitations, is also investigated. Compared with an aluminium ferrule, the present ferrule is better at the suppressing vibrations of the beam, and its adaptive property avoids the structural resonances for bigger ferrule sizes, making it more intelligent, efficient and convenient.

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