7,898 research outputs found
Designing an interactive multimedia instructional environment: the civil war interactive
This article describes the rationales behind the design decisions made in creating The Civil War Interactive, an interactive multimedia instructional product based on Ken Burns''s film series The Civil War
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The systemic environment: at the interface of aging and adult neurogenesis.
Aging results in impaired neurogenesis in the two neurogenic niches of the adult mammalian brain, the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle. While significant work has characterized intrinsic cellular changes that contribute to this decline, it is increasingly apparent that the systemic environment also represents a critical driver of brain aging. Indeed, emerging studies utilizing the model of heterochronic parabiosis have revealed that immune-related molecular and cellular changes in the aging systemic environment negatively regulate adult neurogenesis. Interestingly, these studies have also demonstrated that age-related decline in neurogenesis can be ameliorated by exposure to the young systemic environment. While this burgeoning field of research is increasingly garnering interest, as yet, the precise mechanisms driving either the pro-aging effects of aged blood or the rejuvenating effects of young blood remain to be thoroughly defined. Here, we review how age-related changes in blood, blood-borne factors, and peripheral immune cells contribute to the age-related decline in adult neurogenesis in the mammalian brain, and posit both direct neural stem cell and indirect neurogenic niche-mediated mechanisms
Period derivative of the M15 X-ray Binary AC211/X2127+119
We have combined Rossi X-ray Timing Explorer observations of X2127+119, the
low-mass X-ray binary in the globular cluster M15, with archival X-ray
lightcurves to study the stability of the 17.1 hr orbital period. We find that
the data cannot be fit by the Ilovaisky (1993) ephemeris, and requires either a
7sigma change to the period or a period derivative Pdot/P~9x10e-7 per year.
Given its remarkably low L_X/L_opt such a Pdot lends support to models that
require super-Eddington mass transfer in a q~1 binary.Comment: 11 pages, 3 figures, to be published in New Astronom
Tennessee Law and the Secured Transactions Article of the Uniform Commercial Code
The Uniform Commercial Code in its treatment of personal property security represents a sincere and conscious effort on the part of its draftsmen, authors and sponsors to update and modernize commercial law so as to be able to keep abreast of today\u27s space-age economy. It is submitted that once a familiarity with the new terms,concepts, and theories is acquired, the average practitioner should not encounter any serious difficulty operating under the Uniform Commercial Code and will, in all probability, discover that in most instances the ideas are the same, although perhaps a little hard to recognize at first examination
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