Study of techniques for the reduction of creep in plated wire memories Final report, 28 Jun. 1967 - 28 Aug. 1968

Magnetization reversal in thin films of plated wire memory element

The Effect of Vincristine Sulphate on the Axoplasmic Flow of Proteins in Cultured Sympathetic Neurons

The effect of vincristine sulphate on the axoplasmic flow of labelled proteins in neurites of chick embryo sympathetic neurons growing in tissue culture was studied by autoradiography. In control neurons most of the 3H-proteins synthesized during a 90-min pulse with a 3H-amino acid were localized in cell bodies. There was a diminishing gradient of labelled proteins in the neurites which was highest in portions adjacent to the cell bodies and lowest at the periphery. During a physiological chase there was a gradual increase in the amount of label in the neurites, so that after a 15-h chase even the most peripheral portions were well labelled. This indicates that a portion of the labelled proteins synthesized in the cell bodies are transported peripherally into the neurites. The centrifugal movement of labelled proteins in neurites was markedly decreased when cells were grown in medium containing 10 µg/ml vincristine sulphate. After a 15-h chase in the presence of drug only a small amount of label was in the peripheral portion of the neurites. Treatment with vincristine did not decrease the rate of amino acid incorporation or alter the rate of protein turnover during the course of the experiment. Thus an explanation of the results based on an altered rate of total cell protein synthesis or degradation is unlikely. The capacity of sympathetic neurons to take up and concentrate exogenous [3H]norepinephrine in their neurites was only slightly reduced by vincristine. This indicates that at least some cellular activities requiring metabolic energy are relatively unaffected by the interruption in axoplasmic flow caused by vincristine and that the mechanism by which vincristine interferes with axoplasmic flow does not involve general cellular toxicity. The major morphological differences between control and vincristine-treated neurons were the absence of microtubules and the presence of crystal-like structures within the cells. The relationship between the effect of vincristine on the axoplasmic flow of proteins and the arrangement of the microtubule system is discussed

Assessing the status of urban public school desegregation :

A preliminary examination of desegregation techniques revealed that among elementary schools the combination of pairing and clustering with rezoning proved most successful in reducing racial isolation (operationalized as a change in the index of dissimilarity). For secondary schools the most effective technique was rezoning. These two techniques were associated, in the bivariate case, with the lowest amount of white enrollment loss as well. A multiple regression analysis also showed the most effective desegregation technique to be of some importance (although not statistically significant) in achieving desegregation success when various external, community, and district level forces were taken into account. In the multivariate case, the specific technique was of greater import at the elementary than the secondary level. Other features of the desegregation process, especially support by school officials, were important predictors of desegregation success as well, although the most powerful forces were federal coercion (positive) and size of district (negative). A multivariate analysis of white enrollment change for these 52 districts confirmed recent research that school desegregation does produce a significant one-time decline in white student enrollment. The most important predictor of white student withdrawal was percentage black in the school system.The research concludes that desegregation process variables are important contributors to desegregation success, and certain desegregation techniques may work better than others.Employing a relatively new data collection and aggregation method known as the case survey method and a theoretical framework that conceptualizes school desegregation as a public policy that must be implemented at the local level, an attempt is made to assess the impact of three types of influence--external forces, school district characteristics, and desegregation process variables (including desegregation strategies)--on two school desegregation outcomes: the success of school districts in ending racial isolation (desegregation success) and white enrollment decline (generally referred to as "white flight")

Whole body interaction

In this workshop we explore the notation of whole body interaction. We bring together different disciplines to create a new research direction for study of this emerging form of interaction

Extending electron orbital precession to the molecular case: Can orbital alignment be used to observe wavepacket dynamics?

The complexity of ultrafast molecular photoionization presents an obstacle to the modelling of pump-probe experiments. Here, a simple optimized model of atomic rubidium is combined with a molecular dynamics model to predict quantitatively the results of a pump-probe experiment in which long range rubidium dimers are first excited, then ionized after a variable delay. The method is illustrated by the outline of two proposed feasible experiments and the calculation of their outcomes. Both of these proposals use Feshbach 87Rb2 molecules. We show that long-range molecular pump-probe experiments should observe spin-orbit precession given a suitable pump-pulse, and that the associated high-frequency beat signal in the ionization probability decays after a few tens of picoseconds. If the molecule was to be excited to only a single fine structure state state, then a low-frequency oscillation in the internuclear separation would be detectable through the timedependent ionization cross section, giving a mechanism that would enable observation of coherent vibrational motion in this molecule.Comment: 9 pages, 10 figures, PRA submissio