Continuous and semi continuous measurements of dust emissions in a power plant burning fuel-oil

Some aspects of the suitability of continuously and semi continuously measuring dust emissions with a transmissometer and a beta dust meter were studied at a power plant burning fuel oil. Extinction values were automatically calibrated with the weight of the dust.Data based on gas velocity were selected in six groups and regression analyses were taken between the extinction values and the emissions of dust. A significant regression curve was found in only three of the six groups.These experiments showed that a given mass concentration of dust may correspond with a great variety of extinction values when the particle size changes, so that a correlation between the emitted dust and extinction is valid only when particle size is constant.     

Attitudes towards sex selection in the Western world

It appears that in most Western countries, son preference is somewhat stronger than daughter preference. However, when one considers the preference of women it looks as though the opposite pattern is emerging. There is a considerable social acceptance of ‘light’ methods of sex selection (such as diets), even though these methods are not proven to be effective. The inclination to use sperm separation methods appears to be greater in the United States than in some European countries. There are indications that a preference for boys or for girls is associated with attitudes towards technology, child-rearing style and the stereotyping of boys or girls. Copyright © 2006 John Wiley & Sons, Ltd.     

Prenatal diagnosis of charcot-marie-tooth disease type 1a (CMT1A) using molecular genetic techniques

Charcot-Marie-Tooth disease type 1A (CMT1A) is a frequent hereditary motor and sensory neuropathy of the peripheral nerves. In most cases, the disease is associated with a 1.5 Mb tandem duplication at 17p11.2. A 42-year-old pregnant woman requested prenatal diagnosis because of her age and since both her husband and two children were severely affected with CMT1. The CMT1A duplication was demonstrated in the father's, the two children's, and the fetus's DNA using different molecular genetic methods. Although cytogenetical analysis showed a normal female karyotype in the fetus, the parents decided to terminate the pregnancy because of the genetic risk associated with the CMT1A duplication.     

Prenatal findings in a monozygotic twin pregnancy with Costello syndrome

This report describes the prenatal findings in monozygotic twins with Costello syndrome. At 16 weeks one twin had 9 mm of nuchal oedema: coarctation of the aorta was diagnosed after birth. At 22^5/7 weeks relative macrocephaly, mild pyelectasia and moderate polyhydramnios were noted in both twins. In the following 4 weeks the polyhydramnios increased significantly without visualisation of filling of the stomach. Between 27^5/7 and 30^2/7 weeks a total of 9 l amniotic fluid was drained and at 30^4/7 weeks prelabor premature rupture of membranes (PPROM) occurred followed by premature labor and delivery. The neonatal period was complicated by growth retardation, deglutition problems, hypotonia, cardiac and respiratory problems. Both twins died on Day 57 because of respiratory insufficiency. Copyright © 2002 John Wiley & Sons, Ltd.     

Circulating trophoblast in maternal blood

This review describes the status of circulating trophoblast, but is considered in the perspective that only a specific subset of trophoblast cells circulates in the maternal blood. The consequences for isolation, identification and clinical potential are described. Copyright © 2003 John Wiley & Sons, Ltd.     

Distribution of nickel in the roach (Rutilus rutilus L.) after exposure to lethal and sublethal concentrations

In order to evaluate the eventual impact of nickel in fish kills occuring in the river Meuse in Belgium, a series of experiments were performed in which the uptake and distribution of nickel in Rutilus rutilus L., one of the dominant species in the river was studied after administration of nickel alone and in combination with other metals. In decreasing order the highest nickel concentrations were found in gill, opercle, kidney, liver and muscle. After exposure to nickel in combination with copper or chromium nickel levels in gill tissue increased significantly compared to levels encountered when fish were exposed to the same concentration of nickel alone. When the pH of the test solution was lowered from 8.0 to 6.5, the lethal action and the accumulation of nickel in gill tissue increased. Control fish collected from a surface water storage reservoir and from the river Meuse had higher nickel levels in the opercle than in gill tissue.     

Genetic Variation and Outcrossing Rate in Relation to Population Size in Gentiana pneumonanthe L

The amount of genetic variation in the rare perennial herb Gentiana pneumonanthe L. was determined to explore its relation to population size. Differences in isozyme variation between maternal plants and their offspring were used to investigate the relationship between population size and outcrossing rate. In 25 populations in The Netherlands, differing in size from 1 to more than 50,000 flowering individuals, 16 allozyme loci were analyzed on leaves of maternal plants and offspring grown in a greenhouse. Population size was significantly positively correlated with the proportion of polymorphic loci, but only marginally with heterozygosity and the mean effective number of alleles. Most of the studied populations were characterized by a complete absence of rare alleles, and F -statistics suggest relatively high levels of genetic differentiation among populations and thus a low level of gene flow. Leaf samples (maternal) were mostly in Hardy-Weinberg equilibrium, while several offspring samples showed an excess of homozygotes, which suggests selection favoring heterozygotes. Because most small populations consist only of adult survivors from formerly larger populations, this may partly explain the absence of a clear relationship between genetic variation of the maternal plants and population size. A significant positive correlation was found between the level of cross-fertilization and population size. From these results, we conclude that, to some degree, small populations have a reduced level of genetic variation, while their present isolation in nature reserves has resulted in a very limited interpopulational gene flow level. At present a higher level of inbreeding in small populations contributes to a further loss of genetic variation and may also result in reduced offspring fitness.