Determination of Newton's gravitational constant, G, with improved precision Status report, 1 Apr. - 30 Sep. 1965

Apparatus and techniques for laboratory determination of Newtonian gravitation constan

Pollen Germination in Relation to Group Size

In recent experiments involving the germination of the pollen grains of Vinca rosea, it was observed that relatively poor germination occurred in isolated grains and among those grains aggregated in small groups (Beams and King, 1944). These preliminary observations seemed to warrant a further study of this problem. Accordingly, experiments were designed to determine some of the effects of population density on the percentage germination of these cells

fects of Ultracentrifuging on Certain Cell Structures

Extremely great centrifugal forces may be obtained by the use of the air-driven ultracentrifuge developed by J. W. Beams and his associates. Such forces afford a means of testing the viscosity and relative specific gravity of many cell components. The authors have been able to establish the fact that the Nissl bodies of rat ganglion cells represent a definite material in the cell and are not the result of the action of the fixative used on homogeneous cytoplasm; likewise, for the Golgi material in the uterine gland cells of the guinea pig. In general the chromatin has been shown to be heavier than the non-chromatin materials of the nucleus of various animal and plant cells. In Paramecium the chromatin has been moved centrifugally and there is left in the usual position of the macronucleus an achromatic alveolar mass. In Arcella the chromidia are heavier than the cytoplasm and the karyosomes of the nuclei are displaced toward the centripetal pole

Calculation of the Raman G peak intensity in monolayer graphene: role of Ward identities

The absolute integrated intensity of the single-phonon Raman peak at 1580 cm^{-1} is calculated for a clean graphene monolayer. The resulting intensity is determined by the trigonal warping of the electronic bands and the anisotropy of the electron-phonon coupling, and is proportional to the second power of the excitation frequency. The main contribution to the process comes from the intermediate electron-hole states with typical energies of the order of the excitation frequency, contrary to what has been reported earlier. This occurs because of strong cancellations between different terms of the perturbation theory, analogous to Ward identities in quantum electrodynamics

Determination of newton's gravitational con- stant, g, with improved precision status report, oct. 1, 1964 - mar. 31, 1965

Determination of Newton gravitational constant with improved precisio