Sediment Parameters of Northwest Black Sea Shelf and Slope: Implications for Transport of Heavy Metals and Radionuclides

In June 1990, sediment cores were obtained from several locations in the Northwest Black Sea shelf and slope by a joint US/USSR scientific team aboard the survey vessel R/V VODYANITSKY. the goal of this investigation was to determine the distribution and levels of radioactivity resulting from the Chernobyl 1986 nuclear accident. the sediment was characterized for texture, mineral composition, redox state, heavy metals, and radionuclides. Correlations emerging from these data reveal paths of dispersal and transport of materials from river sources to deposition sites on the shelf and slope. Kaolinite in the clay mineral suite clearly reflects a dispersal pattern originating in the Danube River and progressing in an easterly direction across the shelf. Sand-size gypsum and the elemental heavy metals Zn, Cu, Cr, and Pb (probable industrial source) as well as the elements Al and Mg (probable terrigenous source) also show a dispersal pattern from the Danube station location in an easterly direction across the shelf. the dispersal direction indicated by these materials is not in conflict with recent existing notions concerning the hydrology of the Northwest Black Sea. Barium anomalies at a midshelf location may be related to operations in the Lebada oil fields situated updrift. Heavy mineral dispersal reflect the Danube and -Crimean Provinces established for the shelf and relate to terrestrial source areas. in addition, the heavy mineral monazite correlates with the radioactive Th 232 found most abundantly in the Crimean Province. Local anomalies of Mn, Fe and U in the sediment at station locations are related to redox (Eh) conditions and other factors. Cs^134/137 data, reported by Curtis and Broadway (1991), correspond to transport and dispersal patterns implicit in the mineralogic, anthropogenic indicators, and sediment characteristics of the study area.     

THE OPTIMIZATION OF THE OPERATION OF A MULTI-PURPOSE WATER RESOURCE SYSTEM1

The objective of any water resource system is to transform the natural waters of a river basin into a form such that optimal use of these waters will result. Thus the water may be transformed into electrical energy, transferred in space for water supply and irrigation, transferred in time for flood control and maintenance of adequate streamflows, or simply retained for use as a means for achieving water-based recreation.     

Enhanced susceptibility to infection in mice after exposure to dilute exhaust from light duty diesel engines

A series of experiments was conducted in which groups of mice were first exposed for various durations to diluted exhaust from light duty diesel engines and then briefly to an infectious aerosol generated by nebulizing cultures of a bacterial pathogen (Streptococcus). Typically, postinfection mortality was significantly greater in groups exposed to exhaust than in their corresponding control groups exposed to purified air only. Data of recent diesel and of past diesel- and catalyst-treated gasoline engine exhaust experiments suggest a somewhat greater excess mortality from (enhanced susceptibility to) bacterial infection in mice exposed to diesel exhaust than in those exposed to catalytic gasoline exhaust. Limited data on acute tests of NO₂ and acrolein vapor alone suggest that the infectivity-enhancing effect of diesel exhaust could be accounted for in large part by these components. Exposures to diesel exhaust, NO₂, or acrolein did not enhance the mortality response to a viral pathogen (A/PR8-34).     

论科学、保护与政府的目的地球的功能整体性并不是生物多样性的问题

20年来,人们一直把保护的目的更多地集中在"生物多样性"的保存上,强调物种丧失所可能造成的损失.所提出的解决办法,也一直是建立公园和保护区,以保护那些"热点地区",特别是在生物多样性程度非常高的热带地区.对于生物多样性的保存,常常还包括建立保护区之间的联系,以允许生物在保护区之间移动.这种方法已经得以法规化,例如<美国濒危物种法案(Endangered Species Actinthe United States)>和<生物多样性公约(Biodiversity Treaty)>.这两个法案都逐一列出了应当保护的濒危物种,但都存在着明显的缺陷.这些做法可能是适当的,但是作为拥有60亿人口、掌握着毁灭性技术、为了直接的人类利益而事实上开发了所有的地球资源的世界性保护活动,却是不充分的.作为包括人类在内的所有生物体的栖息地,生物圈的功能正在迅速衰退,这并不是因为物种的消失,而是因为自然群落的不断贫化,这种贫化是由于全球性、普遍存在的人类活动的慢性破坏而产生的.这种自然群落的贫化导致了演变中的环境功能的紊乱,功能紊乱的累积,最后导致了物种的消失.其实,远在物种消失这一问题变得如此重要之前,局地的生物生态型就受到损失了,这在遗传学上是非常清楚的,而且它们赖以发育的自然群落就变得贫化,功能出现了紊乱.最明显的影响是气候上的,这是每一个生态系统都经历的环境的全球变化.自然保护区的最精细、最谨慎的连结方式也无法发挥作用,因为其环境气候发生了改变,而且生物多样性将大幅度丧失.尽管所建立的公园就是为了避免这种丧失,但是在这之前,人类环境就将遭受显著破坏.自然保护的目的,是保存景观(以及水体)的功能整体性.其重点往往是地球上天然林区的森林,因为森林占据了地球上很大的面积,而且对环境的每一方面都有很大影响.在大多数地方,功能的整体需要85%或以上的天然林区结构的整体性.当然,这还需要科学界的客观测定和定义.这样看来,自然保护的实质就发生了变化,它并不是所谓的生物多样性的保存,而是人类环境功能整体性的保存,其核心目的是要求我们以民主形式建立的政府,定义并保护公共利益.现在已经不是迫切需要科学界和保护界认识这种转变、定义新的保护目的以及将这种转变告诉公众的时候了,而是迫切需要政府承担起在这样的责任,即在一个可以栖息的生物圈之中保护公众的利益.     

Maternal cell contamination in cultured chorionic villi: Comparison of chromosome Q-polymorphisms derived from villi,fetal skin,and maternal lymphocytes

Maternal cell contamination of chorionic villi (CV) samples used for first trimester prenatal diagnosis can cause obvious and/or unrecognized diagnostic dilemmas. The purpose of this investigation is to assess the frequency of maternal cell contamination (MCC) in chorionic villus samples and to evaluate selected parameters which might predict where contamination is more likely to have occurred. Maternal lymphocytes, chorionic villi from ultrasonically directed transcervical catheter aspiration, and fetal tissue were obtained at 8–11 weeks gestation from 45 patients undergoing elective termination. Quinacrine (Q) banded metaphases were compared from duplicate direct preparations of chorionic villi; cultured chorionic villi, fetal fibroblast tissue cultures, and maternal lymphocyte cultures. Q-polymorphisms in metaphase chromosomes were 100 per cent concordant between fetal tissue and direct CV preparation. However, evidence for maternal cell contamination occurred in 13.1 per cent of cultured chorionic villi preparations where polymorphisms were found to be identical between maternal and cultured CV and both distinct from fetal tissue preparations. Where MCC was identified, it was noted that CV cell cultivation interval was prolonged (24.2±6.8 days) compared with non-contaminated cultures (14.1±4.4 days) (p <0.05). We conclude that maternal cell contamination is a significant problem with chorionic villus sampling. Where direct preparations are not employed or when cultures are ‘slow growing’, MCC may be a significant and unrecognized complication re: fetal diagnosis. Direct preparations, multiple cultures, quinacrine banding, and maternal Q-polymorphism comparisons can minimize diagnostic dilemmas secondary to maternal cell contamination. Q-polymorphism comparisons between maternal and fetal chromosomes should be included in all instances where cultured chorionic villi are utilized for fetal diagnosis and where direct preparations are not available.     

Prenatal diagnosis of 49,XXXYY

The first prenatally diagnosed case of 49,XXXYY is reported. The pathological findings of the fetus included bilateral clinodactyly, decreased carrying angles (OO), and hypertelorism, slightly low set ears and mildly prominent forehead. A minimum of two independent non- disjunctional events are postulated for this polysomy to arise.     

Risk factors associated with transcervical CVS losses

Factors found to be associated with pregnancy loss after transcervical CVS were race (higher for non-white), history of spontaneous abortion, unplanned pregnancy, history of spotting or bleeding during the pregnancy prior to CVS, and placental position (higher for fundal or lateral locations). Whether the increase in loss risk is due to the factor, per se, or the factor plus the CVS cannot be determined due to the lack of appropriate control data.