Cyanide Chemistry in Comet Hale-Bopp (C/1995 O1)

Observations of comet Hale-Bopp (C/1995 O1) have been carried out near perihelion (1997 March) at millimeter wavelengths using the NRAO 12 m telescope. The J=1-->0, 2-->1, and 3-->2 lines of HCN at 88, 177, and 265 GHz were measured in the comet as well as the J=3-->2 lines of H13CN, HC15N, and HNC. The N=2-->1 transition of CN near 226 GHz was also detected, and an upper limit was obtained for the J=2-->1 line of HCNH+. From the measurements, column densities and production rates have been estimated. A column density ratio of [HCN]/[HNC] = 7+/-1 was observed near perihelion, while it was found that [HCN]/[HCNH+] greater, similar 1. The production rates at perihelion for HCN and CN were estimated to be Q(HCN) approximately 1x1028 s-1 and Q(CN) approximately 2.6x1027 s-1, respectively, resulting in a ratio of [HCN]/[CN] approximately 3. Consequently, HCN is sufficiently abundant to be the parent molecule of CN in Hale-Bopp, and HCNH+ could be a source of HNC. Finally, carbon and nitrogen isotope ratios of 12C/13C = 109+/-22 and 14N/15N = 330+/-98 were obtained from HCN measurements, in agreement with previous values obtained from J=4-->3 data. Such ratios suggest that comet Hale-Bopp formed coevally with the solar system.     

Chlorophyll-deficient propagules of Avicennia marina and apparent longer term deterioration of mangrove fitness in oil-polluted sediments

A correlation between petroleum hydrocarbon concentrations in sediments and chlorophyll-deficient mutations in mangroves may occur also in Australian mangroves. Earlier reports of such mutations in the Caribbean area were evident in viviparous propagules of the common mangrove genera, Rhizophora, borne on otherwise normal trees. These mutant propagules were termed albinos' since they lacked chlorophyll and normal green coloration, leaving them white, yellow or red. The mutation was considered lethal since newly established albino seedlings appeared unable to survive more than a few months. Our preliminary investigation of mangroves in SE Queensland found a similar mutation in another common mangrove genus, Avicennia, and this was apparently also correlated with oil concentrations in sediments. Although, more evidence is required, an apparently similar relationship shows that whatever caused the mutations may act commonly across a diverse range of plant types in quite separate locations. How widespread might this mutation be in mangroves? How many genera and species are affected? Are all occurrences correlated with oil in sediments? Does oil cause the mutation? We discuss these important questions and the potentially serious implications to coastal management where high mutant densities may be indicative of longer term genetic deterioration of mangrove habitat in oil-polluted wetland environments.     

China: population change and population control

Since 1949 China's population has increased by 500 million and thereby grown at an average rate of 2 % per year. Annual growth rates have varied dramatically, falling from 3.3 % in 1963 to 1.2 % in 1979 and registering a population decline of 13.5 million in the famine years of 1960/61. China's demographic disaster in 1958/61 ranks as one of the most devastating in the history of the world. Chinese leaders have oscillated between pro- and anti-natalist policies. However, in the 1970s the government launched its third, its most intensive and to date its most successful family planning programme. So succesful that the total fertility rate declined from 6.4 in 1968 to 2.2 in 1980 and the level of contraceptive use in China was raised to the levels currently experienced in the Developed World. Despite the high rate of contraceptive prevalence, induced abortion is still extensively used to prevent unplanned births. The extent to which China's birth control programme has been implemented on a voluntary, coercive or compulsory basis is open to question. A rapid increase in the age of marriage and a substantial improvement in female education have made important contributions to the decline in fertility. Large differences in fertility exist between rural and urban China, reflecting significant differences in the average age of marriage and the very marked difference in educational attainment between the cities and the countryside. Whether the government directed family planning programme or socio-economic development has had the greatest impact on the decline in fertility, is under discussion. Whatever the motive force, the pace of demographic modernisation has been impressive and by international standards China now enjoys advanced levels of demographic development at an early stage of economic development.Abbreviations CMP-SPRCP-75-114 China Mainland Press, Survey of People's Republic of China Press 1975, No. 114. - FBIS-CHI-83-112 Foreign Broadcast Information Service, Daily Report, China, 1983, No. 112. - JPRS-CPS-85-012 Joint Publications Research Service, China Report, Political, Sociological and Military Affairs, 1985, No. 12. - SWB/FE/6246/BII Summary of World Broadcast, Far East, No. 6246, section BII.     

下科罗拉多河谷与第三纪滑脱断层有关的贱金属和贵金属矿床的控矿因素

引言 在美国西南部盆地—山脉省(盆—岭区),已知许多第三纪滑脱断层(detachmentfault)属于位移很大的低角度正断层,后经上升、倾滑和变形,呈宽缓的起伏面出露于地表。原在深处且处于高温条件下的下盘岩层,经滑脱断层作用移去上覆岩层,发生均衡上升,并穿过一系列温度递次降低的等温面。由于上盘岩层遭受强烈引张,发生侧向位移,使之形成许多上盘断层带,成为热液流体循环的通道。     

GPS与电视信号二者可兼容吗？

１９９１年１１月，飞利蒲实验室（ＰＬ）的地球物理研究会与Ｐｕｒｄｕｅ合作，在密西西比州的Ｉｎｖｅｖｎｅｓｓ附近采用ＧＰＳ测量在６１０米的ＷＡＢＧ电视发射塔周围进行。所获数据用于ＰＬ制定方案研究牛顿重力分离的可能性。数据采集范围为距塔８公里的半径内。在２公里以内，六台ＧＰＳ接收机有半数不能锁定ＧＰＳ信号。笔者认为某睦塔发送的微波信号干扰了ＧＰＳ卫星发送的信号。     

被动边缘及其沉降作用

被动边缘系指地震上不活动的大陆边缘，其与构成会聚板块边界的活动边缘不同之处，在于该处相邻的太陆和大洋岩石圈接合成为一个板块。现今的被动边缘大名分布于较年青且正在变宽的大西洋、北冰洋及印度洋之边缘。此外，太平洋南极侧以及诸如地中海等边缘海内，也发育有被动边缘。反之，环太平洋多以活动边缘为边界。