共查询到20条相似文献,搜索用时 15 毫秒
1.
Hellermans A 《Science (New York, N.Y.)》1995,269(5232):1817-1818
2.
3.
Ralph B. Brown 《Agriculture and Human Values》1991,8(4):46-55
Using an ethnographic case study, this research examines three competing hypotheses of how a community acts. The study attempts to reconstruct the events that led various actors in the community to seek the formation of an industrial base as an alternative economic source for the community. The roles of unique events, specific persons and particular strategies in the formation of the industrial base are examined. It was found that unique events play a very important role in the community's concern over economic alternatives to agriculture and their success in securing such alternatives. These events were also important to key individuals within the community, placing them in positions to act in the industrial base formation. Strategies of community action used in the industrial base formation and since that time were found to be consistent with the centralized weak-tie network hypothesis of action or ganization. This type of community action organization seems to be very effective at the community level but tends to be very exclusionary of the community population as a whole.1. Research supported in part by Project Nos. MO-00239; MO-00237; and MO-00240 of the Missouri Agriculture Experiment Station. This research is part of a larger study through the Missouri Agriculture Experiment Station and the University of Missouri-Columbia Department of Rural Sociology on Rural Community Viability. An earlier version of this paper was presented at the Southern Agricultural Sciences Annual Meeting in Little Rock, Ark., February, 1990. 相似文献
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
The unusual hard x-ray burster GRO J1744-28 recently discovered by the Compton Gamma-Ray Observatory can be modeled as a strange star with a dipolar magnetic field of =10(11) gauss. According to this model, when the accreted mass of the star exceeds some critical mass, its crust breaks, resulting in the conversion of the accreted matter into strange matter and a release of energy. Subsequently, a fireball forms and expands relativistically outward. The expanding fireball interacts with the surrounding interstellar medium, causing its kinetic energy to be radiated in shock waves and producing a burst of x-ray radiation. The burst energy, duration, interval, and spectrum derived from such a model are consistent with the observations of GRO J1744-28. 相似文献
14.
15.
16.
17.
If rats are exposed successively to white noise, then to recorded rat squeals, or alternatively to squeals first and then white noise, and if, in both situations, they are allowed to shut off the auditory stimulation by applying pressure on a bar, they will touch the bar more frequently when exposed to white noise. The results indicate that the bar-pressing behavior is the expression of increased activity resulting from the increased stimulation. 相似文献
18.
Broecker WS 《Science (New York, N.Y.)》2003,300(5625):1519-1522
Two hypotheses have been put forward to explain the large and abrupt climate changes that punctuated glacial time. One attributes such changes to reorganizations of the ocean's thermohaline circulation and the other to changes in tropical atmosphere-ocean dynamics. In an attempt to distinguish between these hypotheses, two lines of evidence are examined. The first involves the timing of the freshwater injections to the northern Atlantic that have been suggested as triggers for the global impacts associated with the Younger Dryas and Heinrich events. The second has to do with evidence for precursory events associated with the Heinrich ice-rafted debris layers in the northern Atlantic and with the abrupt Dansgaard-Oeschger warmings recorded in the Santa Barbara Basin. 相似文献
19.
H C 《Science (New York, N.Y.)》1989,246(4936):1378-1379
20.
Lo KY 《Science (New York, N.Y.)》1986,233(4771):1394-1403
Studies of active galactic nuclei constitute one of the major efforts in astronomy. Massive black holes are the most likely source for the enormous energy radiated from such nuclei. Observations reviewed here suggest unusual activity and the possible existence of a massive black hole in the nucleus of our galaxy. Because of its proximity to Earth, our galactic nucleus can be observed in unsurpassed detail and may serve as the Rosetta stone both for deciphering active galactic nuclei and for confirming the existence of a massive black hole. 相似文献