A Microscopic Self-consistent Calculation with Saturation Diagrams in 16O

1975 ◽  
Vol 53 (20) ◽  
pp. 2261-2266 ◽  
Author(s):  
B. Rouben ◽  
R. Padjen ◽  
D. Gogny ◽  
P. Pirès
Keyword(s):  
State Space ◽  
Single Particle ◽  
Charge Radius ◽  
Particle Removal ◽  
Unoccupied State ◽  
Self Consistent ◽  
G Matrices ◽  
Self Consistency ◽  
Better Than ◽  
Single Particle Basis

Self-consistent calculations are performed in 16O with effective G matrices obtained from two different soft core interactions. The calculations possess the 'triple' self-consistency: (a) on the single particle basis, (b) on the single particle eigenvalues (Brueckner self-consistency), and (c) on the occupation probabilities. Two different procedures of calculating the latter are carried out, one involving a truncation of the unoccupied state space, one involving no truncation. The truncation effects are studied and shown to increase with the hardness of the interaction. A comparison is also made to calculations where the Brueckner self-consistency is satisfied only on the average. The total and single particle removal energies for both forces are quite satisfactory, the Pirès – Gogny – de Tourreil interaction performing slightly better than that of de Tourreil – Sprung. The charge radius is approximately 10% too small.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

scholarly journals Reinforcement learning versus swarm intelligence for autonomous multi-HAPS coordination

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Ogbonnaya Anicho ◽  
Philip B. Charlesworth ◽  
Gurvinder S. Baicher ◽  
Atulya K. Nagar
Keyword(s):  
Reinforcement Learning ◽  
State Space ◽  
Swarm Intelligence ◽  
Performance Indicators ◽  
Convergence Rates ◽  
Tuning Parameters ◽  
Continuous State Space ◽  
Continuous State ◽  
User Coverage ◽  
Better Than

AbstractThis work analyses the performance of Reinforcement Learning (RL) versus Swarm Intelligence (SI) for coordinating multiple unmanned High Altitude Platform Stations (HAPS) for communications area coverage. It builds upon previous work which looked at various elements of both algorithms. The main aim of this paper is to address the continuous state-space challenge within this work by using partitioning to manage the high dimensionality problem. This enabled comparing the performance of the classical cases of both RL and SI establishing a baseline for future comparisons of improved versions. From previous work, SI was observed to perform better across various key performance indicators. However, after tuning parameters and empirically choosing suitable partitioning ratio for the RL state space, it was observed that the SI algorithm still maintained superior coordination capability by achieving higher mean overall user coverage (about 20% better than the RL algorithm), in addition to faster convergence rates. Though the RL technique showed better average peak user coverage, the unpredictable coverage dip was a key weakness, making SI a more suitable algorithm within the context of this work.

scholarly journals Diffusion in CP Stars: The Quest for Accuracy

1998 ◽  
Vol 11 (2) ◽  
pp. 671-673
Author(s):  
G. Alecian
Keyword(s):  
Computational Methods ◽  
Stellar Evolution ◽  
Diffusion Processes ◽  
Stellar Atmospheres ◽  
Time Dependent ◽  
Data Bases ◽  
Self Consistent ◽  
Stellar Envelopes ◽  
Better Than

We present a brief review about recent progresses concerning the study of diffusion processes in CP stars. The most spectacular of them concerns the calculation of radiative accelerations in stellar envelopes for which an accuracy better than 30% can now be reached for a large number of ions. This improvement is mainly due to huge and accurate atomic and opacity data bases available since the beginning of the 90’s. Developments of efficient computational methods have been carried out to take advantage of these new data. These progresses have, in turn, led to a better understanding of how the element stratification is building up with time. A computation of self-consistent stellar evolution models, including time-dependent diffusion, can now be within the scope of the next few years. However, the progresses previously mentioned do not apply for stellar atmospheres and upper layers of envelopes.

scholarly journals Self-consistent treatment of v-groove quantum wire band structure in no parabolic approximation

2004 ◽  
Vol 1 (3) ◽  
pp. 69-77 ◽  
Author(s):  
Jasna Crnjanski ◽  
Dejan Gvozdic
Keyword(s):  
Band Structure ◽  
Quantum Wire ◽  
The Self ◽  
Flat Band ◽  
Band Model ◽  
Parabolic Approximation ◽  
Self Consistent ◽  
Band Absorption ◽  
Consistent Treatment ◽  
Self Consistency

The self-consistent no parabolic calculation of a V-groove-quantum-wire (VQWR) band structure is presented. A comparison with the parabolic flat-band model of VQWR shows that both, the self-consistency and the nonparabolicity shift sub band edges, in some cases even in the opposite directions. These shifts indicate that for an accurate description of inter sub band absorption, both effects have to be taken into the account.

scholarly journals Self-consistent dual boson approach to single-particle and collective excitations in correlated systems

2016 ◽  
Vol 93 (4) ◽  
Author(s):  
E. A. Stepanov ◽  
E. G. C. P. van Loon ◽  
A. A. Katanin ◽  
A. I. Lichtenstein ◽  
M. I. Katsnelson ◽  
...  
Keyword(s):  
Single Particle ◽  
Collective Excitations ◽  
Correlated Systems ◽  
Self Consistent

CURRENTS, SPIN DENSITIES AND MEAN-FIELD FORM FACTORS IN ROTATING NUCLEI: A SEMI-CLASSICAL APPROACH

2004 ◽  
Vol 13 (01) ◽  
pp. 225-233 ◽  
Author(s):  
J. BARTEL ◽  
K. BENCHEIKH ◽  
P. QUENTIN
Keyword(s):  
Mean Field ◽  
Form Factors ◽  
Spin Vector ◽  
Self Consistent ◽  
Field Form ◽  
Local Densities ◽  
The Mean ◽  
Self Consistency ◽  
Spin Densities ◽  
Rotating Nuclei

We present self-consistent semi-classical local densities characterising the structure of rotating nuclei. A particular emphasis is put on those densities which are generated by the breaking of time-reversal symmetry through the cranking piece of the Routhian, namely the current density and the spin vector density. Our approach which is based on the Extended-Thomas-Fermi method goes beyond the Inglis cranking approach and contains naturally the Thouless-Valatin self-consistency terms expressing the response of the mean field to the time-odd part of the density matrix.

scholarly journals The Arctic Ocean Multi-Year Ice Balance, 1979-82

1990 ◽  
Vol 14 ◽  
pp. 252-255 ◽  
Author(s):  
D.A. Rothrock ◽  
D.R. Thomas
Keyword(s):  
Arctic Ocean ◽  
Open Water ◽  
Measurement Model ◽  
The Arctic ◽  
First Year ◽  
Independent Data ◽  
Self Consistent ◽  
Buoy Data ◽  
Parameter Values ◽  
Self Consistency

A method of determining the temporally varying “state” of the ice cover (the concentrations of three surface types: open water, first-year ice, and multi-year ice) is presented. The methodology is that of Kalman smoothing: a physical model and a measurement model are used to blend satellite passive microwave data and buoy data to give an optimal estimate of the ice state. The estimates are optimal only to the degree that model parameter values are known and assumptions about variances are met. Uncertainty about these values and assumptions, and lack of independent data with which to compare results,leaves self-consistency as the most important test of results. A four-year record (1979-82) of the estimated Arctic Ocean ice balance is presented and shown to be self-consistent. Results are discussed in terms of the Arctic multi-year ice balance, which may be an important factor in the interaction ofocean, sea ice and climate because of its relationship to the minimum summer ice extent. The estimated area of multi-year ice decreases each year, but the decrease is small and insignificant based on four years of results. Furthermore, the observed decrease may be due to instrument drift or changes in the multi-year ice signature.

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