S-100 protein in amniotic fluid of anencephalic fetuses

S-100 protein, which is found essentially in the astrocytes of the nervous system, was assayed in amniotic fluids by Particle Counting Immuno Assay. It was present in 19 cases of anencephaly out of 26, in 1 case of open spina bifida out of 5 and in each of the 4 cases of fetal death, whereas it was not detected in the 48 control amniotic fluids collected between the 16th and the 35th week of gestation. Thirty-one amniotic fluids from fetuses with other congenital malformations were devoid of detectable S-100. The presence of S-100 in amniotic fluid of anencephalic fetuses can presumably be considered as a biological sign of necrosis of the exencephalic brain and seems specific to damage of the central nervous system accompanied by neural tube defect.     

Canadian perspectives on aluminum

Summary The multi-media approach to aluminum exposure will allow a more informed decision on the inclusion or exclusion of various exposure media in future epidemiological studies.Knowledge of the types of Al (speciation) and their respective bioavailability will enable interpretation of the importance of specific media.     

Atmospheric BTEX-concentrations in an area with intensive street traffic

The major threat to clean air in developed and industrializing countries is now posed by traffic emissions. The effects of traffic road modifications on the air quality are, however, rarely reported in the literature. The aim of this study was to determine the influence of the modernization and renovation of a traffic artery in the region of Mortsel (Antwerp, Belgium) on the concentration of volatile organic compounds such as: benzene, toluene, ethylbenzene and m-, p-, o-xylenes (BTEX). The original goal of the reconstruction works was to reduce the traffic lanes of one of the busiest streets in Antwerp, in order to discourage the road traffic and in consequence also to improve the air quality in this region. The average concentrations of BTEX before these works in 2003 were: 1.6, 7.0, 0.9, 2.3, and 0.9 μg/m³, for benzene, toluene, ethylbenzene, m + p xylenes, and o-xylene, respectively. However, after the completion of the works, in 2005, they were slightly higher: 2.5, 9.5, 1.6, 3.4, and 1.3 μg/m³, respectively. The scatter plots of benzene against toluene, ethylbenzene and xylenes in 2003 and 2005 showed very good correlations. This fact indicated that all of the measured compounds originated from the same source, namely the road traffic. Moreover, the data obtained from an air-monitoring station at less than 6 km distance from the sampling site (operated by the Flemish Environment Agency, and located in Borgerhout, Antwerp), confirmed the lack of influence of background concentrations of BTEX. The obtained results led to the conclusion that the reduction of the number of traffic lanes had apparently increased the traffic jams and also increased the emission from cars. Therefore, these modernization works had even a negative impact on the local concentration of traffic-related pollutants as BTEX.     

Ecological planning proposal for Kruger National Park

This article discusses an application of the ecological planning model proposed by Van Riet and Cooks. The various steps outlined in this model have been applied to Kruger National Park in South Africa. The natural features of Kruger National Park, which form the basis of such an ecological planning exercise and from which the various land use categories, values, and zoning classes can be determined, are discussed in detail. The suitability of each of the various features is analyzed and a final zoning proposal for Kruger National Park is suggested. Furthermore a method for selecting a site for a new camp is illustrated by referring to the site for the new Mopane rest camp which is now under construction in the Kruger National Park. The conclusion is reached that the proposed ecological planning model can be used successfully in planning conservation areas such as Kruger National Park and for the selection of the most desirable sites for the establishment of new rest camps. Its suitability as a practical model in such planning exercises is proven by the fact that the siting proposals of two new camps based on this model have been accepted by the National Parks Board, the controlling body of Kruger National Park.     

Controlling substance flows: The case of chlorine

The contribution of chlorinated hydrocarbons (CHCs) to environmental problems in the Netherlands is discussed in an economic context. The economic interactions within the chlorine market, including the link to caustic soda production, are described, and PVC is taken as a case study. Key policy options are evaluated in terms of their potential for environmental improvement. It appears that 95% of CHC emissions causing environmental problems are due to dissipative applications. With respect to the specific problems of ozone depletion and global warming, only a small group of compounds is responsible for most of the impact. Moreover, economic interactions within the group of CHCs can strongly influence the net effect of environmental policy measures. Policies aimed at a reducing volume output of certain specific groups of CHCs will inevitably lead to trade-offs between environmental problems. The environmental impact of a hypothetical ban on CHCs is discussed in relation to the use of PVC as a sink for chlorine. Both these options appear to have drawbacks. Moreover, no absolute conclusion can be drawn until the environmental impact of CHC substitutes is known.     

Ecological design criteria for a sustainable Canadian society

Summary The purpose of this paper is to develop specific ecological design criteria for a sustainable Canadian society. Ecological design criteria complement socio-political ones which have also been developed by the Sustainable Society Project at the University of Waterloo. The criteria derive from an evaluation of the major areas of human activity and interaction with the natural environment in light of our knowledge of ecological systems and resource management. The criteria, like the Sustainable Society Project as a whole, are an attempt to suggest needed, feasible, medium to long-term changes in human activities to comply with the ecological and socio-political limits and constraints that must be recognized in order to achieve societal sustainability. The specific design criteria identified here are not the only ones possible, desirable, or necessary — a complete and certain list is inherently impossible. But the design criteria developed here are illustrative of the kinds of changes that are necessary to achieve sustainability.Dr D. Scott Slocombe is Assistant Professor in the Department of Geography, and Co-Director of the Cold Regions Research Centre, Wilfrid Laurier University. His principal research interests include ecosystem and regional planning, and management for sustainability.Caroline Van Bers was Project Manager for the Sustainable Society Project at the University of Waterloo and she received her MA from the School of Urban and Regional Planning at that University. She currently works in the State of the Environment Reporting Branch of Environment Canada.     

THE STABILITY IN WATER OF A NEW CHLORAMINE DISINFECTANT1

ABSTRACT: The stability in water of a novel new chloramine agent, 3-chloro-4, 4-dimethyl-2-oxazolidinone (agent I), which is an excellent water disinfectant, has been compared to the stabilities of several other water disinfectants. The agents tested in addition to agent I included N-chlorosuccinimide, 2, 4-dichloro-5, 5-dimethylhydantoin, tichloroisocyanuric acid, calcium hypochlorite, commercial grade HTH, and household bleach. The total chlorine content of a water solution of agent I in a demand free environment remains constant over a period of at least eight weeks, while that for all of the other agents declines markedly over that time period. An explanation for these observations will be offered. Prior work in these laboratories concerning use of agent I as a disinfectant for lake water in a laboratory scale treatment plant had shown that agent I has considerable potential for use as an alternative to chlorine gas for water disinfection.     

DESIGN FOR A STABLE CHANNEL IN COARSE ALLUVIUM FOR RIPARIAN ZONE RESTORATION1

Geomorphic, hydraulic and hydrologic principles are applied in the design of a stable stream channel for a badly disturbed portion of Badger Creek, Colorado, and its associated riparian and meadow complexes. The objective is to shorten the period of time required for a channel in coarse alluvium to recover from an impacted morphologic state to a regime condition representative of current watershed conditions. Channel geometry measurements describe the stream channel and the normal bankfull stage in relatively stable reaches. Critical shear stress equations were used to design a stable channel in noncohesive materials with dimensions which approximate those of less disturbed reaches. Gabion controls, spaced at approximately 300 m intervals, are recommended to help reduce the chance of lateral migration of the newly constructed channel. Controls are designed to allow for some vertical adjustment of the channel bed following increased bank stability due to revegetation. The flood plain is designed to dissipate flood flow energy and discourage multiple flood channels. The channel has approximately a 90 percent chance of remaining stable the first two years following construction, the time estimated for increased stability to occur due to revegetation.     

Generations as social categories: An exploratory cognitive study of generational identity and generational stereotypes in a multigenerational workforce

Even though the academic press recognizes generational diversity and its consequences, the related findings are fractured, and research is incomplete regarding methodology and theoretical background. In adopting a social identity perspective concerning groups and self‐conception, we argue that the social identity perspective is in line with generational identity theory. Employing a cognitive mapping method (repertory grid technique, mixed methods), the present study taps into three generations (Baby Boomers, Generation X, and Generation Y) of Belgian managers' minds and demonstrates how they perceive their own and the two other generations. Our research reveals that perceptions of their own and other generations may direct social categorization and generational stereotypes of the in‐group and out‐group(s), that some of these stereotypes can be enacted, and that generational stereotypes do not necessarily coincide with age‐based stereotypes. Several metapatterns in the stereotypes are revealed as well. Hence, we contribute to the emerging field of research that calls for an identity‐based approach rather than a cohort‐based approach to generations and that validates the argument that generations as a workplace phenomenon must be considered a legitimate phenomenon. Insights into generations as social categories give a richer view of the interrelationships between generations in multigenerational situations at work.