Age of the earliest african anthropoids     

Fleagle JG  Bown TM  Obradovich JD  Simons EL 《Science (New York, N.Y.)》1986,234(4781):1247-1249

The earliest fossil record of African anthropoid primates (monkeys and apes) comes from the Jebel Qatrani Formation in the Fayum depression of Egypt. Reevaluation of both geologic and faunal evidence indicates that this formation was deposited in the early part of the Oligocene Epoch, more than 31 million years ago, earlier than previous estimates. The great antiquity of the fossil higher primates from Egypt accords well with their primitive morphology compared with later Old World higher primates. Thus, the anthropoid primates and hystricomorph rodents from Fayum are also considerably older than the earliest higher primates and rodents from South America.  相似文献   

Optical experiments and weak interactions     

Bouchiat MA  Pottier L 《Science (New York, N.Y.)》1986,234(4781):1203-1210

Recent optical experiments have demonstrated cases in which mirror symmetry in stable atoms is broken during absorption of light. These results, which are in contradiction with quantum electrodynamics, support the theory of unification of the electromagnetic and weak forces. The interpretation of these experimental results is based on exchanges of weak neutral Z(0) bosons between the electrons and the nucleus of the atom. The information obtained from low-energy experiments is different from, but complementary to, the results of high-energy experiments. Sensitive measurements in a simple, reliably computable atom are in quantitative agreement with the standard electroweak theory and put stringent constraints on alternative models. Attaining sufficient accuracy in the experiments and the computations for the electroweak radiative corrections to manifest themselves is now the challenge for experimenters and theorists.  相似文献   

Changing climate: geothermal evidence from permafrost in the alaskan arctic   总被引：2，自引：0，他引：2  

Lachenbruch AH  Marshall BV 《Science (New York, N.Y.)》1986,234(4777):689-696

Temperature profiles measured in permafrost in northernmost Alaska usually have anomalous curvature in the upper 100 meters or so. When analyzed by heat-conduction theory, the profiles indicate a variable but widespread secular warming of the permafrost surface, generally in the range of 2 to 4 Celsius degrees during the last few decades to a century. Although details of the climatic change cannot be resolved with existing data, there is little doubt of its general magnitude and timing; alternative explanations are limited by the fact that heat transfer in cold permafrost is exclusively by conduction. Since models of greenhouse warming predict climatic change will be greatest in the Arctic and might already be in progress, it is prudent to attempt to understand the rapidly changing thermal regime in this region.  相似文献   

Some other books of interest: the human skeleton     

L K 《Science (New York, N.Y.)》1986,232(4751):780

  相似文献   

Sinking Slabs Puncture Layered Mantle Model: Seismologists are finding that oceanic plates sinking into the mantle plunge right through the supposedly impenetrable boundary between the upper and lower mantle     

Kerr RA 《Science (New York, N.Y.)》1986,231(4738):548-549

  相似文献   

Black holes--"ingestars"?     

Shurcliff WA 《Science (New York, N.Y.)》1986,231(4744):1355

  相似文献   

Some other books of interest: inorganic reactions and methods     

L K 《Science (New York, N.Y.)》1986,233(4768):1103

  相似文献   

Cell lineages traced in zebrafish embryos     

Marx JL 《Science (New York, N.Y.)》1986,231(4736):340

  相似文献   

Porcine rabies in a closed feeder barn          下载免费PDF全文

Hazlett MJ  Koller MA 《The Canadian veterinary journal. La revue veterinaire canadienne》1986,27(3):116-118

Rabies was diagnosed in a 40 kg pig from a closed feeder barn in which recently unexplained deaths of eight to ten pigs had occurred. A stray cat, probably crawling through a ventilation duct into the barn, was the suspected vector. Over a four and one-quarter year period a disproportionate 53 cases of animal rabies had been diagnosed within a 5 km radius of the farm (13% of the cases in the county in 3% of the county area). Histological lesions, mostly lymphocytic cuffing of blood vessels in the brain with lymphocytic meningitis, patchy to focal gliosis and satellitosis with neuronal necrosis were nonspecific and Negri bodies were rare. Fluorescent antibody technique examination of the brain for rabies virus antigen was positive.  相似文献   

Improved yersinia isolation from enteric specimens          下载免费PDF全文

Lynch JA 《The Canadian veterinary journal. La revue veterinaire canadienne》1986,27(3):154

  相似文献