底泥中酸性挥发硫及同步浸提金属的测定

同步浸提金属与酸性挥发硫的比值在判断底泥重金属生物毒性方面有重要意义．描述了一套测定底泥酸性挥发硫和同步浸提金属的仪器装置和分析程序．从气体流速、反应时间、酸浓度、硫含量等方面研究了酸性挥发硫测定的最适反应条件．在此条件下酸性挥发硫的测定回收率可达９０％以上．该方法的最低检出限为００２μｍｏｌ／ｇ（干泥）．     

Prenatal diagnosis of GM2-gangliosidosis B1 variant

Prenatal diagnosis in a pregnancy at risk for a juvenile B1 variant of GM₂-gangliosidosis was carried out. The biochemical study of the cultured amniocytes and the affected fetal brain is reported. The results obtained show that the sulphated artificial substrate can be used in the diagnosis of B1 variant, but not the neutral one. The accumulation of GM₂-ganglioside in the fetal brain of the B1 juvenile form and an infantile form of GM₂-gangliosidosis (0 variant) was compared.     

城市生活垃圾堆肥对水稻生长和土壤的影响

利用城市生活垃圾堆肥作为肥料,采用水培法和土培法对水稻生长和土壤的影响进行了试验研究。结果表明,施用城市生活垃圾堆肥明显提高了水稻的生长量,增加了水稻植株茎叶中硅的含量;降低了糙米中有毒元素镉的含量;改变了土壤的酸度,增强了土壤的肥力;水稻植株和土壤中某些有害元素的含量略有增加,但远低于环境的允许值。     

Chorionic villus sampling—short-term versus long-term culture in a subtle 2; 18 translocation

Prenatal diagnosis on chorionic villous tissue was performed for a woman with the karyotype 46,XX,t(2;18)(q32;q12)—a subtle ‘difficult’ translocation. The case illustrates the necessity of good quality cytogenetics for accurate prenatal diagnosis. For chorionic villi this can be obtained only with long-term culture.     

Mating System and Sexual Selection in the Scorpionfly Panorpa vulgaris (Mecoptera: Panorpidae)

Panorpa vulgaris   has become a model insect for testing theories of sexual selection. This contribution summarizes that which has been learned in recent years and presents new data that clearly show that the mating system of P. vulgaris is not simply a resource-defense polygyny, as has previously been thought. In P. vulgaris neither the pattern in food exploitation nor the ratio of variance in the lifetime reproductive success of the two sexes is in accordance with that expected in resource defense polygynous mating systems. Lifetime mating duration is the most important proximate determinant of male fitness. Males employing alternative mating tactics obtain copulations of varying duration in relation to the following sequence: saliva secretion  1  food offering  1  no gift. The number of salivary masses which males provide to females during their lifetime is significantly correlated with the lifetime condition index. The condition index depends on the fighting prowess of males and their ability to find food items. Thus saliva secretion of Panorpa is considered a Zahavian handicap, which can serve as an honest quality indicator used by mating females. Our results confirm four main predictions of the indicator model of the theory of sexual selection: (a) the indicator signals high ecological quality of its bearer, (b) the indicator value increases with phenotypic quality, (c) the indicator value is positively correlated with the genetic quality affecting offspring fitness in a natural selection context, and (d) the quality indicator is more costly for low- than for high-quality individuals. The evolutionary consequences of the mating pattern and the sperm competition mechanism in P. vulgaris are discussed in the context the way in which sexual selection creates and maintains sperm mixing and the evolution of a promiscuous mating system.     

Impacts of climate change on wheat development and production in the northern China

In this paper, impacts of climate change on wheat development rate and production in the northern China are discussed. The results show that the temperature is a controlling factor of development rate but the precipitation is not. The higher the temperature is. the faster the development and the shorter development period will be. Without consideration to varieties and cropping system, meteorological yield of winter wheat would decrease 170.40, 134.25, 98.70 and 97.20 kg/hm2 in the north China and 13.97, 7.95, 39.60 and 19.80 kg/hm2 in the northwest China compared with that in 1950s, 1960s, 1970s and 1980s, respectively, when the CO2 concentration in the atmosphere is doubled. In drought and semi-drought regions, the spring wheat yield would drop with the temperature rise in and raise with the precipitation increase. The influence of temperature on weight of leaf and stalk is also remarkable.