Bacterial lysis of cytoplasm of Cosmarium,a green alga

Summary The protoplast of the green alga Cosmarium is lysed by a coccoid bacterium, whereas the cell wall remains intact. Pyrenoids are more resistant to lytic action than the rest of the chloroplast. Different stages of the lysis are described.We thank the Heads of the Botany and Soils Departments for providing laboratory facilities. Thanks are also due to Dr V. R. P. Garg for help in photography.     

A precision measurement of the mass of the top quark

The standard model of particle physics contains parameters--such as particle masses--whose origins are still unknown and which cannot be predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark (M(t)) and W boson (M(W)) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of M(t) can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10(-24) s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of +/- 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for M(t) becomes 178.0 +/- 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.     

藏族传统建筑艺术--访著名藏族传统建筑艺术理论与设计家木雅·曲吉建才先生

木雅.曲吉建才教授是藏族传统建筑领域成绩卓著,影响颇大的专家。他于藏历1947年6月4日出生在今康定(古西夏王国)热瓦岗没落土司米祖西家族。四岁被确认为格鲁派木雅古瓦寺的第八世木雅活佛的转世灵童而登上了该寺主持活佛的宝座。1958年在拉萨哲蚌寺学经,之后又在当时新组建的佛学院学习,文革时期被分到军区山南农场基建连从事土建工程,1974在拉萨城关区建筑公司当施工员,1976年参加自治区建筑设计院和城关区建筑公司联合举办的施工员培训班,以优异的成绩留在了自治区建筑设计院从事建筑设计工作,专攻藏族传统建筑。教授的设计作品遍布全区各地,出版专著多部,曾多次参加国际、国内的建筑、藏学学术研讨会。文章围绕藏族传统建筑艺术进行了专访。     

Epidemiological evidence for causal relationship between Epstein-Barr virus and Burkitt's lymphoma from Ugandan prospective study.

Results from a prospective sero-epidemiological study initiated in Uganda in 1971 indicate that children with high antibody titres to Epstein-Barr virus structural antigens are at high risk of developing Burkitt's lymphoma. These findings strongly support a causal relationship between the Epstein-Barr virus and Burkitt's lymphoma but suggest that the oncogenic potential of the virus is realised only in exceptional circumstances.