THE ADVANCEMENT OF SCIENCE     

Phillips EP 《Science (New York, N.Y.)》1942,96(2479):1-3

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Chlorine-36 dating of saline sediments: preliminary results from searles lake, california     

Phillips FM  Smith GI  Bentley HW  Elmore D  Gove HE 《Science (New York, N.Y.)》1983,222(4626):925-927

Measurements have been made of the ratios of chlorine-36 to chlorine in five halite samples from Searles Lake sediments, previously dated by carbon-14, thorium-230, and magnetostratigraphic techniques. The ages calculated from the chlorine ratios are generally concordant with those from the other methods, implying the constancy of the chlorine input ratio over the last million years.  相似文献   

HEMOGLOBIN REGENERATION IN ANEMIC TROUT FED LIVER FRACTIONS AND FLY MAGGOTS     

Phillips AM  McCay CM 《Science (New York, N.Y.)》1941,93(2415):355-356

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Fossil plants and coal: patterns of change in pennsylvanian coal swamps of the illinois basin     

Phillips TL  Peppers RA  Avcin MJ  Laughnan PF 《Science (New York, N.Y.)》1974,184(4144):1367-1369

Coal palynology and studies of petrified peat indicate major changes in coal-swamp floras and the botanical constituents of coal throughout Pennsylvanian time. The changes are the result of broad climatic shifts and local environmental factors. The most striking is the change from a lycopod-dominated flora to one in which tree ferns were the major element. This change occurred at the Desmoinesian-Missourian (Westphalian-Stephanian) boundary and is probably multicontinental in scope.  相似文献   

Radar soundings of the subsurface of Mars   总被引：2，自引：0，他引：2  

Picardi G  Plaut JJ  Biccari D  Bombaci O  Calabrese D  Cartacci M  Cicchetti A  Clifford SM  Edenhofer P  Farrell WM  Federico C  Frigeri A  Gurnett DA  Hagfors T  Heggy E  Herique A  Huff RL  Ivanov AB  Johnson WT  Jordan RL  Kirchner DL  Kofman W  Leuschen CJ  Nielsen E  Orosei R  Pettinelli E  Phillips RJ  Plettemeier D  Safaeinili A  Seu R  Stofan ER  Vannaroni G  Watters TR  Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.  相似文献   

Extending Symbiotic Nitrogen Fixation to Increase Man's Food Supply     

Phillips DA  Torrey JG  Burris RH 《Science (New York, N.Y.)》1971,174(4005):169-170

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Magnetic Anomalies over the Mid-Atlantic Ridge near 27{degrees}N     

Phillips JD 《Science (New York, N.Y.)》1967,157(3791):920-923

Ten magnetic profiles across the mid-Atlantic ridge near 27 degrees N show trends that are parallel to the ridge axis and symmetrical about the ridge axis. The configuration of magnetic bodies that could account for the pattern supports the Vine and Matthews hypothesis for the origin of magnetic anomalies over oceanic ridges. A polarity-reversal time scale inferred from models for sea-floor spreading in the Pacific-Antarctic ridge and radiometrically dated reversals of the geomagnetic field indicates a spreading rate of 1.25 centimeters per year during the last 6 million years and a rate of 1.65 centimeters per year between 6 and 10 million years ago. A similar analysis of more limited data over the mid-Atlantic ridge near 22 degrees N also indicates a change in the spreading rate. Here a rate of 1.4 centimeters per year appears to have been in effect during the last 5 million years; between 5 and 9 million years ago, an increased rate of 1.7 centimeters per year is indicated. The time of occurrence and relative magnitude of these changes in the spreading rate, about 5 to 6 million years ago and 18 to 27 percent, respectively, accords with the spreading rate change implied for the Juan de Fuca ridge in the northeast Pacific.  相似文献   

New Opportunities in Synchrotron X-ray Crystallography     

Prewitt CT  Coppens P  Phillips JC  Finger LW 《Science (New York, N.Y.)》1987,238(4825):312-319

Several high-intensity synchrotron x-ray sources have been constructed over the past few years in the United States, West Germany, Great Britain, Japan, France, Italy, and the Soviet Union. Crystallographers have begun to use these facilities for experiments that take advantage of the characteristics of synchrotron radiation, namely, a broad distribution of wavelengths, high intensity, low divergence, strong polarization, and a pulsed time structure. In addition to more familiar diffraction experiments on single crystals and powdered samples, new types of crystallographic studies, for example, energy-dispersive and surface diffraction studies, have progressed rapidly with more general accessibility of synchrotron sources. These high-intensity sources allow diffraction experiments to be performed on very small crystals or on large biological molecules, and permit weak magnetic scattering to be detected Anomalous dispersion experiments can exploit he ability to vary the wavelength of the radiation, and the pulsed time structure of the beam makes possible fast time-resolved experiments. Because of the availability of synchrotron x-radiation, these and other kinds of experiments will be in the forefront of crystallographic research for the next several years.  相似文献   

Discovery of transposable element activity among progeny of tissue culture--derived maize plants     

Peschke VM  Phillips RL  Gengenbach BG 《Science (New York, N.Y.)》1987,238(4828):804-807

Tissue culture-derived plants of many species have often been observed to possess both genetic and cytogenetic abnormalities. A high frequency of structurally altered chromosomes in maize (Zea mays L.) plants regenerated from tissue culture led to the prediction that newly activated transposable elements could be detected in regenerated plants. Testcrosses of 1200 progeny from 301 regenerated maize plants confirmed that ten regenerated plants from two independent embryo cell lines contained an active Actransposable element. No active Ac elements were present in the explant sources. Recovery of transposable element activity in regenerated plants indicates that some tissue culture-derived genetic variability may be the result of insertion or excision of transposable elements, or both.  相似文献   

Recent Discoveries in the Egyptian Faiyum and Sinai     

Phillips W 《Science (New York, N.Y.)》1948,107(2791):666-670

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