Showing papers in "Science in 1955"

Citation Indexes for Science: A New Dimension in Documentation through Association of Ideas

Abstract: Objectives To investigate whether longitudinal structural network efficiency is associated with cognitive decline and whether baseline network efficiency predicts mortality in cerebral small vessel disease (SVD). Methods A prospective, single-centre cohort consisting of 277 non-demented individuals with SVD was conducted. In 2011 and 2015, all participants were scanned with MRI and underwent neuropsychological assessment. We computed network properties using graph theory from probabilistic tractography and calculated changes in psychomotor speed and overall cognitive index. Multiple linear regressions were performed, while adjusting for potential confounders. We divided the group into mild-to-moderate white matter hyperintensities (WMH) and severe WMH group based on median split on WMH volume. Results The decline in global efficiency was significantly associated with a decline in psychomotor speed in the group with severe WMH (β=0.18, p=0.03) and a trend with change in cognitive index (β=0.14, p=0.068), which diminished after adjusting for imaging markers for SVD. Baseline global efficiency was associated with all-cause mortality (HR per decrease of 1 SD 0.43, 95% CI 0.23 to 0.80, p=0.008, C-statistic 0.76). Conclusion Disruption of the network efficiency, a metric assessing the efficiency of network information transfer, plays an important role in explaining cognitive decline in SVD, which was however not independent of imaging markers of SVD. Furthermore, baseline network efficiency predicts risk of mortality in SVD that may reflect the global health status of the brain in SVD. This emphasises the importance of structural network analysis in the context of SVD research and the use of network measures as surrogate markers in research setting.

U.S. Geological Survey Radiocarbon Dates II

Abstract: ADIOCARBON dates of samples fo r which R were made in the laboratory of the U.S. Geological Survey from 1 May to 1 5 Oct. 1954 are listed in this article (1). Together with the first list of dates ( 2 ) ,this list presents the results obtained on 127 samples of previously unknown age during the first year of laboratory operation. The experimental procedure (3) and evaluation of the measurements have remained the same over the entire period of time, except that during June 1954 a complete set of new equipment that essentially duplicated the first set was installed and put into operation. AIost of the samples listed were measured in both sets of counting equipment f o r a counting time of 1 day in each set. The ages given are weighted averages of the two measurements. Deviations in the results from the two sets correspond to those expected from statistics. Corrinne Alexander continued to assist in the preparation of the samples. Our main efforts continued to be directed toward establishing a n absolute time scale f o r the pre-Mankato substages of the last glaciation. Further evidence of the glacial advance on the North American continent around 20,000 yr ago was accumulated. The deposits representing this glaciation consist of a t least most of the till of the Tazewell substage in Illinois and the drift called early Cary in Ohio. A glacial advance in the mountains of the western United States was determined to have occurred about 3000 vr ., ago. u

Statistical Interpretation of Quantum Mechanics.

Abstract: The published work for which the honor of the Nobel prize for the year 1954 has been accorded to me does not contain the discovery of a new phenomenon of nature but, rather, the foundations of a new way of thinking about the phenomena of nature. This way of thinking has permeated experimental and theoretical physics to such an extent that it seems scarcely possible to say anything more about it that has not often been said already. Yet there are some special aspects that I should like to discuss.

Evidence that serotonin has a role in brain function.

Abstract: Action of Parapyruvate on Early Development of Strongylocentrotus Purpuratus: C. M. Montgomery and J. W. Bamberger .... ............ 967 Evidence That Serotonin Has a Role in Brain Function: B. B. Brodie, A. Pletscher, P. A. Shore ..... ......................... 968 Systematic Effect of C14-Labeling on Ion-Exchange Chromatography of Amino Acids: K. A. Piez and H. Eagle ..... ...................... 968 Thallium Acetate in the Diagnosis of Chronic Respiratory Disease of Chickens: N. L. Shipkowitz and M. K. Clarke .... ................ 969 Isotopic Composition of Common Lead from Southern Africa: G. L. Bate and J. L. Kulp ....... ................................. 970 Tetrazolium-Reduction Test for Milk: K. K. Mustakallio, E. 0. Ahos, E. 0. Autio .... ..................... 971 Fluorescence Characteristics of 5-Hydroxytryptamine (Serotonin ): S. Udenfriend, D. F. Bogdanski, H. Weissbach .... .................. 972

Age of the Earth.

Abstract: A new method for estimating the age of the earth consists of calculating a Pb^207 / Pb^206 age from the observed differences between the isotropic composition of recent lead isolated from the surface of the earth where appreciable concentrations of uranium exist and the isotropic composition of lead isolated from iron meteorites where insignificant concentrations of uranium are found (1-3).

Yale Natural Radiocarbon Measurements II

Abstract: One of the series of "Yale natural radiocarbonmeasurements, II" [ Science 122, 954 (1955)], byRichard S. Preston, Elaine Person, and E. S.Deevey, was incorrectly reported through a technical error. The date for sample Y-293A (SouthHaven, Mich.: peat) was 10,790 ± 200 yr, not9500 + 250 yr as reported on page 958.