1,408 research outputs found
People on the move: trends and prospects in District migration flows
Since the early 1970s, the states of the Tenth Federal Reserve District have experienced wide swings in economic activity and interstate migration. The swings in migration not only reflect the region's economic performance but also have important consequences for future economic activity.> Miller discusses recent trends and prospects for migration into and out of the district. He reviews trends in net migration flows and shows how they correspond with swings in district economic performance. Next, he examines the composition of migrant flows and indicates that a significant brain drain occurred from much of the district in the late 1980s. Finally, he considers the migration outlook for the district.Federal Reserve District, 10th ; Emigration and immigration
Secondary electron emission due to positive ion bombardment
Stray electrons were produced in the Ames Laboratory linear accelerator by the ion beam striking the target and various other parts of the accelerator. This experiment was done to determine if the stray electrons from parts of the accelerator other than the target could be reduced by using construction materials other than brass. Measurements of the number of electrons produced from several materials, however, indicated that there is no particular advantage in using other materials in place of brass
Common Cause Failure Prediction Using Data Mapping
To estimate power plant reliability, a probabilistic safety assessment might combine failure data from various sites. Because dependent failures are a critical concern in the nuclear industry, combining failure data from component groups of different sizes is a challenging problem. One procedure, called data mapping, translates failure data across component group sizes. This includes common cause failures, which are simultaneous failure events of two or more components in a group. In this paper, we present methods for predicting future plant reliability using mapped common cause failure data. The prediction technique is motivated by discrete failure data from emergency diesel generators at U.S. plants. The underlying failure distributions are based on homogeneous Poisson processes. Both Bayesian and frequentist prediction methods are presented, and if non-informative prior distributions are applied, the upper prediction bounds for the generators are the same
Exposure of Vascular Smooth Muscle Cells for Analysis with the Scanning Electron Microscope
There has been interest in using the scanning electron microscope (SEM) to study the structure of tissues obscured by other cellular or non-cellular elements almost since the SEM was first used to examine biological tissues. Such interest includes the vessel wall and, in particular, the vascular smooth muscle cells. This paper presents a review of the three basic methodologies that have been employed to allow examination of the vascular smooth muscle, 1) blunt dissection, 2) digestion and 3) microdissection. Discussion of other perivascular elements was not a focus of this review. Also presented is the application of these different methodologies to different pathophysiologic conditions
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