scholarly journals Null point of discrimination in crustacean polarisation vision

2014 ◽  
Vol 217 (14) ◽  
pp. 2462-2467 ◽  
Author(s):  
M. J. How ◽  
J. Christy ◽  
N. W. Roberts ◽  
N. J. Marshall
Keyword(s):  
Null Point ◽  
Polarisation Vision

scholarly journals A Cyclic Iterative Algorithm for Multiple-Sets Split Common Fixed Point Problem of Demicontractive Mappings without Prior Knowledge of Operator Norm

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 372
Author(s):  
Nishu Gupta ◽  
Mihai Postolache ◽  
Ashish Nandal ◽  
Renu Chugh
Keyword(s):  
Fixed Point ◽  
Common Fixed Point ◽  
Prior Knowledge ◽  
Iterative Algorithm ◽  
Fixed Point Problem ◽  
Null Point ◽  
Operator Norm ◽  
Point Problem ◽  
Common Fixed Point Problem ◽  
Split Common Fixed Point

The aim of this paper is to formulate and analyze a cyclic iterative algorithm in real Hilbert spaces which converges strongly to a common solution of fixed point problem and multiple-sets split common fixed point problem involving demicontractive operators without prior knowledge of operator norm. Significance and range of applicability of our algorithm has been shown by solving the problem of multiple-sets split common null point, multiple-sets split feasibility, multiple-sets split variational inequality, multiple-sets split equilibrium and multiple-sets split monotone variational inclusion.

Instability of isolated three-dimensional magnetic null points

1998 ◽  
Vol 59 (3) ◽  
pp. 537-541 ◽  
Author(s):  
MANUEL NÚÑEZ
Keyword(s):  
Linear Stability ◽  
Three Dimensional ◽  
Null Point ◽  
Static Equilibrium ◽  
Flux Surface ◽  
Form Part ◽  
Magnetic Null ◽  
Transverse Oscillations

Although most magnetic neutral points occurring in nature seem to form part of a continuum, recent studies of reconnection have centred on static equilibria in the neighbourhood of an isolated three-dimensional null point. The linear stability of this configuration is studied here. It is found that one may choose a flux surface so that transverse oscillations localized around the surface and polarized within it must grow exponentially in time. This means that any static equilibrium containing an isolated three-dimensional null point is linearly unstable.

scholarly journals GALOIS THEORY OF THE CANONICAL THETA STRUCTURE

2011 ◽  
Vol 07 (01) ◽  
pp. 173-202
Author(s):  
ROBERT CARLS
Keyword(s):  
Galois Theory ◽  
Theoretical Foundation ◽  
Abelian Varieties ◽  
Geometric Mean ◽  
Null Point ◽  
Point Counting ◽  
Characteristic 2 ◽  
Theoretic Characterization ◽  
Generalized Arithmetic

In this article, we give a Galois-theoretic characterization of the canonical theta structure. The Galois property of the canonical theta structure translates into certain p-adic theta relations which are satisfied by the canonical theta null point of the canonical lift. As an application, we prove some 2-adic theta identities which describe the set of canonical theta null points of the canonical lifts of ordinary abelian varieties in characteristic 2. The latter theta relations are suitable for explicit canonical lifting. Using the theory of canonical theta null points, we are able to give a theoretical foundation to Mestre's point counting algorithm which is based on the computation of the generalized arithmetic geometric mean sequence.

Population Dynamics and Regeneration of a Hybrid Zone Between Eucalyptus risdonii Hook-F and E amygdalina Labill

1986 ◽  
Vol 34 (3) ◽  
pp. 305 ◽  
Author(s):  
BM Potts
Keyword(s):  
Hybrid Zone ◽  
Null Point ◽  
Asymmetric Distribution ◽  
Hybrid Swarm ◽  
Population Response ◽  
Pure Species ◽  
Seed Migration ◽  
Hybrid Swarms ◽  
Population Turnover ◽  
Phenotypic Fitness

Regeneration of a hybrid zone between E. amygdalina and E. risdonii and pure species stands following wildfire is reported, as well as the reproductive and vegetative fitness of parental and hybrid phenotypes. E. risdonii phenotypes dominated the seed rain and seedling cohort and there was clearly a marked fitness differential between E. amygdalina and E. risdonii at their boundary. When the F1 type hybrid is in competition with both parental types it is generally reproductively the least fit, although frequently vegetatively vigorous. Reduced fitness appears to extend to advanced generations as hybrid phenotypes tending.toward either species are, on average, less fit than the corresponding parental type. The pattern of phenotypic fitness suggests that the species' boundary is in disequilibrium and it is argued that E. risdonii is invading the range of E. amygdalina by both pollen and seed migration. There is an asymmetric distribution of F1 type hybrids across the boundary and the hybrid swarm examined is being invaded by E. risdonii genes. It is suggested that hybridization may be associated with natural disequilibrium and, where seed migration is limited, boundary movements may be preceded by a wave of hybridization due partly to pollen swamping of the least fit species. Hybrid swarms may develop but, at the boundary of large stands, are probably transitory. There is a marked inertia in the population response to the prevailing selective regime due to the extremely slow population turnover and limited dispersal potential. This is discussed in the broader context of non-equilibrium models where it is argued that dispersal may be the factor limiting population response to perturbation of a shallow environmental gradient. This is due to large geographical shifts in the position of the null point and would be accentuated in a patchy environment where migration as a front is prevented.

Cluster Observation of Electrostatic Solitary Waves around Magnetic Null Point in Thin Current Sheet

2010 ◽  
Vol 27 (1) ◽  
pp. 019401 ◽  
Author(s):  
Li Shi-You ◽  
Deng Xiao-Hua ◽  
Zhou Meng ◽  
Yuan Zhi-Gang ◽  
Wang Jing-Fang ◽  
...  
Keyword(s):  
Current Sheet ◽  
Solitary Waves ◽  
Null Point ◽  
Thin Current Sheet ◽  
Magnetic Null ◽  
Magnetic Null Point

An iterative algorithm with inertial technique for solving the split common null point problem in Banach spaces

2021 ◽  
pp. 2250120
Author(s):  
Yan Tang ◽  
Pongsakorn Sunthrayuth
Keyword(s):  
Banach Spaces ◽  
Split Feasibility Problem ◽  
Null Point ◽  
Feasibility Problem ◽  
Strong Convergence Theorem ◽  
Point Problem ◽  
Inertial Algorithm ◽  
The Split Feasibility Problem ◽  
Inertial Technique ◽  
Split Feasibility

In this work, we introduce a modified inertial algorithm for solving the split common null point problem without the prior knowledge of the operator norms in Banach spaces. The strong convergence theorem of our method is proved under suitable assumptions. We apply our result to the split feasibility problem, split equilibrium problem and split minimization problem. Finally, we provide some numerical experiments including compressed sensing to illustrate the performances of the proposed method. The result presented in this paper improves and generalizes many recent important results in the literature.

Free concentrations of intracellular fluorescent anions determined by cytoplasmic dialysis of isolated hepatocytes

1994 ◽  
Vol 267 (5) ◽  
pp. G922-G931 ◽  
Author(s):  
S. A. Weinman ◽  
L. M. Maglova
Keyword(s):  
Isolated Hepatocytes ◽  
Null Point ◽  
Free Concentration ◽  
Intracellular Location ◽  
Organic Ions ◽  
Cytoplasmic Proteins ◽  
Solution Bound ◽  
Intracellular Vesicles ◽  
Fluorescent Molecules ◽  
Intracellular Fluorescence

Intracellular organic ions exist in free solution bound to cytoplasmic proteins, partitioned within intracellular membranes, and enclosed in intracellular vesicles and organelles. The aim of this study was to develop a method for measurement of the free cytosolic concentration of organic ions. This was accomplished by measuring initial rates of diffusion between patch-clamp pipettes and cell cytoplasm and determining the null-point concentration of this process. Carboxydimethylfluorescein (CF) was used as a model compound. It readily diffused between cytoplasm and pipette, and there was a linear relationship between concentration in the pipette and equilibrium cell fluorescence. When cells previously loaded with CF were patched, intracellular fluorescence rapidly changed in a positive or a negative direction, depending on the concentration of CF in the pipette. The null point, defined as the concentration at which cells neither gained nor lost fluorescence, described the same relationship between free concentration and total cell fluorescence as that determined by direct loading of the cells to equilibrium. In hepatocytes preloaded with a fluorescent bile acid derivative, cholylglycylamidofluorescein (CGamF), by exposure (0.05 microM) for 30 min, the null point occurred at a CGamF concentration in the pipette of 0.6 microM. This value is 12 times greater than that in the bath. In conclusion, a new method is described that can measure free cytosolic concentrations of fluorescent molecules. It should prove useful in determining the intracellular location and state of transported organic ions.

An experimental evaluation of simplified procedures for determining the proton spin–lattice relaxation rates of natural products

1980 ◽  
Vol 58 (19) ◽  
pp. 2016-2023 ◽  
Author(s):  
Lawrence D. Colebrook ◽  
Laurance D. Hall
Keyword(s):  
Natural Products ◽  
Lattice Relaxation ◽  
Null Point ◽  
Proton Spin ◽  
Computational Method ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Simplified Procedures

A general discussion is given of the determination of the proton spin–lattice relaxation rates of natural products, with particular emphasis on use of the null-point method which, for the systems studied here, gives identical results with those obtained via the conventional (and relatively time consuming) computational method.

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