Vertical diurnal migration and endogenous rhythmicity     

Enright JT  Hamner WM 《Science (New York, N.Y.)》1967,157(3791):937-941

Experimental studies of mixed populations of marine zooplankton have demonstrated that internal rhythms, synchronized by a light-dark cycle, are of dominant importance for the vertical migration of several species of crustaceans. For certain other organisms, the vertical migrations observed in the experiments can be accounted for as direct responses to light intensity only. Performances intermediate between these extremes were also observed, as well as behavior based on biological timing mechanisms that are not rhythms in the usual sense.  相似文献   

SECTION ON BOTANICAL SCIENCES (G) AND AFFILIATED SOCIETIES     

Buchholz JT  Avery GS  Betts EM  Schopf JM  Burkholder PR  Jones CH  Barss HP  Pinckard JA  Studhalter RA  Loomis WE  Whitney EG 《Science (New York, N.Y.)》1940,91(2353):112-116

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Temperature, cloud structure, and dynamics of venus middle atmosphere by infrared remote sensing from pioneer orbiter     

Taylor FW  Diner DJ  Elson LS  McCleese DJ  Martonchik JV  Delderfield J  Bradley SP  Schofield JT  Gille JC  Coffey MT 《Science (New York, N.Y.)》1979,205(4401):65-67

Further results from the Venus orbiter radiometric temperature experiment (VORTEX) on the Pioneer orbiter are presented. These are used to characterize the three-dimensional temperature field, the cloud structure, and the dynamics of the 60-to 130-kilometer altitude region of the Venus atmosphere. One of the new discoveries is a "dipole" structure at high latitudes, with two hot spots rotating around the pole, surrounded by banks of cold cloud.  相似文献   

Calcium carbonate production of the mare incognitum, the upper windward reef slope, at enewetak atoll     

Smith SV  Harrison JT 《Science (New York, N.Y.)》1977,197(4303):556-559

Corals and algal pavement produce calcium carbonate more slowly on the windward reef slope of Enewetak Atoll than on the reef flat despite the high standing crop of reef-building organisms on the slope. The capacity of reefs to remain at or near sea level is therefore not determined primarily by growth on the seaward slope.  相似文献   

上海食用菌病害调查初报     

康素珍 《上海交通大学学报(农业科学版)》1989,(4)

食用菌是一种创汇农业,国际上誉为“保健食品”,营养丰富,常食菇类可降低血压和胆固醇,所以深受国内外群众欢迎。然而食用菌与其他植物一样,也会遭受真菌、细菌、线虫和病毒等危害,造成严重的经济损失。  相似文献   

Poliomyelitis in Monkeys: Decreased Susceptibility after Avoidance Stress     

Marsh JT  Lavender JF  Chang SS  Rasmussen AF 《Science (New York, N.Y.)》1963,140(3574):1414-1415

Eleven monkeys were subjected to avoidance stress for 24 hours followed immediately by intravenous inoculation with type I poliovirus. Twelve control monkeys not so stressed were similarly inoculated. Seven of 11 stressed animals survived the infection while only one of the controls lived and their average incubation period was significantly longer than the average for controls. The number of circulating lymphocytes decreased significantly in experimental animals during and immediately after exposure to stress.  相似文献   

Beyond economics and nutrition: the complex basis of food policy     

Dwyer JT  Mayer J 《Science (New York, N.Y.)》1975,188(4188):566-570

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AN ASPECT OF THE RELATION BETWEEN ABUNDANCE,MIGRATION AND RANGE IN BIRDS     

Nichols JT 《Science (New York, N.Y.)》1918,48(1233):168-170

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Intersection of the RNA interference and X-inactivation pathways   总被引：1，自引：0，他引：1  

Ogawa Y  Sun BK  Lee JT 《Science (New York, N.Y.)》2008,320(5881):1336-1341

In mammals, dosage compensation is achieved by X-chromosome inactivation (XCI) in the female. The noncoding Xist gene initiates silencing of the X chromosome, whereas its antisense partner Tsix blocks silencing. The complementarity of Xist and Tsix RNAs has long suggested a role for RNA interference (RNAi). Here, we report that murine Xist and Tsix form duplexes in vivo. During XCI, the duplexes are processed to small RNAs (sRNAs), most likely on the active X (Xa) in a Dicer-dependent manner. Deleting Dicer compromises sRNA production and derepresses Xist. Furthermore, without Dicer, Xist RNA cannot accumulate and histone 3 lysine 27 trimethylation is blocked on the inactive X (Xi). The defects are partially rescued by truncating Tsix. Thus, XCI and RNAi intersect, down-regulating Xist on Xa and spreading silencing on Xi.  相似文献   

A BREATHINGS WELL IN LOGAN COUNTY,KANSAS     

Willard JT 《Science (New York, N.Y.)》1892,20(515):337-338

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