A model to minimize joint total costs for industrial waste producers and waste management companies.

The model LINKopt is a mixed-integer, linear programming model for mid- and long-term planning of waste management options on an inter-company level. There has been a large increase in the transportation of waste material in Germany, which has been attributed to the implementation of the European Directive 75/442/EEC on waste. Similar situations are expected to emerge in other European countries. The model LINKopt has been developed to determine a waste management system with minimal decision-relevant costs considering transportation, handling, storage and treatment of waste materials. The model can serve as a tool to evaluate various waste management strategies and to obtain the optimal combination of investment options. In addition to costs, ecological aspects are considered by determining the total mileage associated with the waste management system. The model has been applied to a German case study evaluating different investment options for a co-operation between Daimler-Chrysler AG at Rastatt, its suppliers, and the waste management company SITA P+R GmbH. The results show that the installation of waste management facilities at the premises of the waste producer would lead to significant reductions in costs and transportation.     

Amniotic fluid levels of human chorionic gonadotropin and its alpha and beta subunits in second-trimester chromosomally abnormal pregnancies

Amniotic fluid from 135 pregnancies was assayed for human chorionic gonadotropin (hCG) and its free alpha (ahCG) and free beta (bhCG) subunits. Forty-six chromosomally abnormal pregnancies between 14 and 20 weeks' gestation were matched with 89 chromosomally normal samples. Compared with controls, trisomy 21 pregnancies exhibited significantly elevated levels of all three peptides, whereas trisomy 18 gestations gave rise only to significant elevation of ahCG. Female fetuses in both the trisomy 21 and trisomy 18 pregnancies provided significantly elevated levels of hCG and bhCG compared to their male counterparts. On converting the values to multiples of the median, it was determined that 6 of 7 trisomy 18 samples had abnormally elevated alpha/beta ratios, as did 6 of 21 Down's syndrome pregnancies. Further, 11 of 21 trisomy 21 gestations had abnormal amniotic fluid hCG levels. Using only ahCG, bhCG and their ratio, a 61 per cent sensitivity was found for these trisomies, with a 96 per cent specificity.     

Air pollution and diseases of the respiratory tracts in pre-school children: A transfer function model

The purpose of the present statistical analysis was the assessment of the relation between time series of environmental factors and of frequencies of diseases of the respiratory system in pre-school children. During about one year, daily measurements of air pollutants and climatic variables were taken. During the same period of time two series of medical data were collected: (i) The daily relative number of pre-school children, exhibiting diseases of the respiratory tracts who either came to the outpatients' clinic of the children's hospital or were reported by paediatricians in Basle (ENTRIES). (ii) The daily relative frequency of symptoms of the respiratory tracts observed in a group of randomly selected pre-school children (SYMPTOMS).By means of transfer function models the relation between the two target variables and the explaining variables was analysed. Several practical problems did arise: Choice of the appropriate transformation of the different series, interpretation of the crosscorrelation function using different methods of prewhitening, time splitting and nonstationarity of the crosscorrelation structure. In particular, it was found that after prewhitening the crosscorrelation function between the explanatory series SO₂ and the response series SYMPTOMS changes with time. While during the winter period an instantaneous relation between these two series (and to a lesser extent between NO₂ and SYMPTOMS) was identified, no such relation was found for the other seasons.     

Synthetische Nitromoschus-Duftstoffe und Bromocyclen Neue Umweltchemikalien in Fischen und Muscheln bzw. Muttermilch und Humanfett

Es wird über Kontaminationen mit synthetischen benzoiden Nitromoschus-Verbindungen Moschus Xylol, Moschus Keton, Moschus Ambrette, Moschus Mosken in verschiedenen Fischarten aus Binnengew?ssern und Forellen aus Aquakulturen, Muscheln, Muttermilch und Humanfett berichtet. Bromocyclen wurde in Sü?wasserfischen — besonders Forellen aus dem Ausland — gefunden. Die Nitromoschus-Verbindungen werden in gro?en Mengen unter anderem als Duftstoffe in Waschmitteln, Seifen, Cremes und Lotions verwendet. Es wird über ?kotoxikologische Wirkungen (Fischtoxizit?t), den biologischen Abbau und das Biokonzentrationspotential dieser Umweltchemikalien in Fischen berichtet. Neben der oralen Aufnahme über die Nahrung mu? beim Menschen die Hautresorption und die inhalative Aufnahme von Nitromoschus-Verbindungen berücksichtigt werden. Um diese Rückst?nde im Menschen und in Lebensmitteln zu reduzieren bzw. zu vermeiden, wird an die Hersteller von Nitromoschus-Verbindungen bzw. an die Riechstoff-, Kosmetik- und Reinigungsmittelindustrie appelliert, aus Vorsorgegründen auf die Herstellung bzw. den Einsatz von Nitromoschus-Verbindungen und Bromocyclen in allen ihren Produkten zu verzichten.