Relativistic Corrections to Nonrelativistic Two-Particle Dynamical Calculations: Demonstration of the Validity of the Drell-Hearn-Gerasimov Sum Rule for Weakly Bound Composite Particles

1968 ◽  
Vol 176 (5) ◽  
pp. 1523-1533 ◽  
Author(s):  
Hugh Osborn
Keyword(s):  
Composite Particles ◽  
Weakly Bound ◽  
Sum Rule ◽  
Relativistic Corrections

Relativistic corrections to the Drell-Hearn-Gerasimov sum rule in the constitutent quark model

1994 ◽  
Vol 16 (4) ◽  
pp. 143-150 ◽  
Author(s):  
M. De Sanctis ◽  
D. Drechsel ◽  
M. M. Giannini
Keyword(s):  
Quark Model ◽  
Sum Rule ◽  
Relativistic Corrections

scholarly journals Relativistic corrections to the Bethe sum rule

1986 ◽  
Vol 33 (4) ◽  
pp. 2827-2829 ◽  
Author(s):  
P. T. Leung ◽  
M. L. Rustgi ◽  
S. A. T. Long
Keyword(s):  
Sum Rule ◽  
Relativistic Corrections

scholarly journals GAMOW–TELLER SUM RULE IN RELATIVISTIC NUCLEAR MODELS

2006 ◽  
Vol 21 (12) ◽  
pp. 935-946 ◽  
Author(s):  
HARUKI KURASAWA ◽  
TOSHIO SUZUKI
Keyword(s):  
Degrees Of Freedom ◽  
Random Phase ◽  
Mean Field ◽  
Field Approximation ◽  
Point Of View ◽  
Mean Field Approximation ◽  
Sum Rule ◽  
Relativistic Mean Field ◽  
Relativistic Corrections ◽  
Gamow Teller

Relativistic corrections are investigated to the Gamow–Teller (GT) sum rule with respect to the difference between the β- and β+ transition strengths in nuclei. Since the sum rule requires the complete set of the nuclear states, the relativistic corrections come from the anti-nucleon degrees of freedom. In the relativistic mean field approximation, the total GT strengths carried by the nucleon sector is quenched by about 12% in nuclear matter, while by about 8% in finite nuclei, compared to the sum rule value. The coupling between the particle-hole states with the nucleon–antinucleon states is also discussed with the relativistic random phase approximation, where the divergence of the response function is renormalized with use of the counterterms in the Lagrangian. It is shown that the approximation to neglect the divergence, like the no-sea approximation extensively used so far, is unphysical, from the sum-rule point of view.

Relativistic Corrections to the Dipole Sum Rule

1957 ◽  
Vol 106 (6) ◽  
pp. 1191-1194 ◽  
Author(s):  
J. S. Levinger ◽  
M. L. Rustgi ◽  
K. Okamoto
Keyword(s):  
Sum Rule ◽  
Relativistic Corrections

CRYO-Electron Microscopy of the Acto-Myosin-ATP Complex

1990 ◽  
Vol 48 (1) ◽  
pp. 248-249
Author(s):  
John Trinickt ◽  
Howard White
Keyword(s):  
Electron Microscopy ◽  
Atp Hydrolysis ◽  
Myosin Head ◽  
Bound State ◽  
Cross Linking ◽  
Weakly Bound ◽  
Cryo Electron Microscopy ◽  
Myosin Subfragment 1 ◽  
Attached State ◽  
High Fraction

The primary force of muscle contraction is thought to involve a change in the myosin head whilst attached to actin, the energy coming from ATP hydrolysis. This change in attached state could either be a conformational change in the head or an alteration in the binding angle made with actin. A considerable amount is known about one bound state, the so-called strongly attached state, which occurs in the presence of ADP or in the absence of nucleotide. In this state, which probably corresponds to the last attached state of the force-producing cycle, the angle between the long axis myosin head and the actin filament is roughly 45°. Details of other attached states before and during power production have been difficult to obtain because, even at very high protein concentration, the complex is almost completely dissociated by ATP. Electron micrographs of the complex in the presence of ATP have therefore been obtained only after chemically cross-linking myosin subfragment-1 (S1) to actin filaments to prevent dissociation. But it is unclear then whether the variability in attachment angle observed is due merely to the cross-link acting as a hinge.We have recently found low ionic-strength conditions under which, without resorting to cross-linking, a high fraction of S1 is bound to actin during steady state ATP hydrolysis. The structure of this complex is being studied by cryo-electron microscopy of hydrated specimens. Most advantages of frozen specimens over ambient temperature methods such as negative staining have already been documented. These include improved preservation and fixation rates and the ability to observe protein directly rather than a surrounding stain envelope. In the present experiments, hydrated specimens have the additional benefit that it is feasible to use protein concentrations roughly two orders of magnitude higher than in conventional specimens, thereby reducing dissociation of weakly bound complexes.

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