Tenuous structures from disorderly growth processes     

Witten TA  Cates ME 《Science (New York, N.Y.)》1986,232(4758):1607-1612

Colloidal aggregation and other random growth processes produce structures that behave differently from ordinary bulk matter. Much of this behavior can be described in terms of the invariance of the aggregates under changes of spatial length scale: they appear to be fractals. There are two types of basic mechanisms for producing fractal aggregates. Those in which aggregation proceeds cluster by cluster can be understood qualitatively in terms of a solvable schematic model. The diffusion-limited aggregation or deposition of individual particles to make a large cluster is not as well understood. It is closely related to several irreversible processes in other areas of physics, such as two-fluid displacement in porous materials and the dielectric breakdown of insulators. More generally, disorderly growth mechanisms provide structures having unique properties, many of which can be understood by using simple statistical principles.  相似文献   

Geometry problem     

Finegold LX  Tyagi SD 《Science (New York, N.Y.)》1986,232(4758):1588

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Response: effects of growth hormone-releasing factor in the brain     

Tannenbaum GS 《Science (New York, N.Y.)》1986,232(4755):1272-1273

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Ethics and the professional     

Painter S 《Science (New York, N.Y.)》1986,231(4742):1160-1161

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Greenhouse Warming still Coming: Estimates of the carbon dioxide-induced climate warming predict a large effect that could be doubled by increasing trace gases; some effects of the warming may already be evident     

Kerr RA 《Science (New York, N.Y.)》1986,232(4750):573-574

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Social psychology: attribution     

Kruglanski AW 《Science (New York, N.Y.)》1986,232(4750):665-666

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Japanese competitiveness and Japanese management     

Minabe S 《Science (New York, N.Y.)》1986,233(4761):301-304

Japanese-style management and industrial policy are shown to serve as a source of industrial dynamism and are used as a way to illminate what is wrong with the American system. Japanese labor practices-specifically extra hours of unpaid work-are seen as a form of insurance fee that the worker pays in exchange for job security.  相似文献   

Use of paramunization in raising pigs     

A Mayr 《Tier?rztliche Praxis》1986,14(2):237-244

The fundamentals of paramunization are briefly discussed to provide better understanding of paramunization of pigs. Veterinary practice and experimental studies demonstrate the usefulness, efficacy and harmlessness of paramunization of pigs. Mortality, morbidity as well as weight gain in piglets are used to evaluate the effect of the inducers PIND-AVI and/or PIND-ORF on piglets which have been treated shortly after birth. The therapeutic effect of paramunization has been studied in herds with enzootic pneumonia. Paramunization is especially suitable in stimulating the immune system, in treating immune deficiencies, in the prophylaxis of the stress syndrome (e.g. induced by transport, weaning, changing stalls, etc.) and in treating pluricausal, multifactorial infectious diseases such as enzootic pneumonia, rhinitis atrophicans, "crowding" disease. Paramunization of pigs is discussed, using PIND-ORF as an example of a biological inducer. Paramunization as a biological method to stimulate immunity provides a new concept of prophylaxis and therapy opposed to the uncontrolled use of chemicals in pig production.  相似文献   

Using databases     

L S Rivkin 《Veterinary Clinics of North America: Small Animal Practice》1986,16(4):647-668

Through a relatively simple computer technique known as online searching, practitioners can use computers to "reach out" beyond their practice walls to expand their knowledge base. By bringing information sources closer to veterinarians, feelings of isolation, frustration, and ineptitude can be replaced with feelings of certainty, confidence, and knowledge. This article explores the equipment and the software needed, and by giving examples of a few of the veterinary databases, illustrates some techniques employed in signing up and signing on to the power of online searching.  相似文献   

On new book of anatomy of horse (Kaiba Shinsho) by Tosui Kikuchi in Japan     

Matsuo S 《Historia medicinae veterinariae》1986,11(3):65-70

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