ERYTHEMAL UV-B IRRADIANCE (ROBERTSON-BERGER SUNBURN METER DATA) UNDER OZONE DEFICIENCIES IN WINTER/SPRING 1993

Abstract –Robertson-Berger sunburn meter data recorded from August 1992 to May 1993 (Innsbruck, 577 m above sea level, Austria) were compared with measurements taken in previous years. In February and March 1993 instantaneous values on clear days were found to be higher by up to 37% than those registered in previous years (1986–1988). However, in winter/spring 1993 daily totals for all days, averaged over 7 days, were within the range of standard deviation of the previous years (1981–1988). Therefore the cumulative UV-B exposure of the ecosystem is within the general range of variability even under the record low ozone values in winter/spring 1993, while single peak doses were enhanced significantly.     

Ein verallgemeinertes Transportproblem

Zusammenfassung Das Transportproblem wird dahingehend verallgemeinert, daß nicht der Transport eines einheitlichen Gutes, sondern der Transport verschiedener Sorten betrachtet wird. Gesucht ist ein optimaler Verteilungsplan, der gleichzeitig vorschreibt, in welchen Mengen die einzelnen Sorten in den Versandorten am besten produziert werden, wobei für diese Mengen obere Schranken gegeben sind. Es wird gezeigt, daß sich die geschilderte Aufgabe auf ein gewöhnliches Transportproblem zurückführen läßt. Diese Tatsache ist vor allem deshalb interessant, da dadurch der Aufwand für die numerische Bearbeitung solcher Aufgaben wesentlich herabgesetzt wird.

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Summary The transportation-problem is generalized by considering not the transport of a uniform commodity, but of goods of various kinds. The obejetive is to find an optimal distribution plan, prescribing at the same time the quantities in which the different kinds of goods have to be produced in the places of dispatch, if maximum amounts are given for these goods. It is shown that the problem in question can be reduced to a normal transportation-problem. This is especially important on account of the fact that it leads to a considerable reduction of the cost of treating problems of this kind.

     

The pyrolytic behavior of ethylenetetracarboxylic acid

The controlled pyrolysis of ethylenetetracarboxyclic acid at 220°C followed by methylation of the pyrolyzate results in the formation of methyl propiolate as the major product along with lesser amounts of methyl fumarate. Evidence is presented which indicates that the methyl fumarate probably arises from some precursor in the pyrolyzate during the methylation reaction. Extended heating of the tetra acid at its melting point produces, in addition to the substances cited above, ethylenetetracarboxylic dianhydride and dicarboxymaleic anhydride. The high-temperature (300–400°C) pyrolysis of the tetraacid gives l0–20% yields of dimethylmaleic anhydride.     

Intersection numbers for coherent configurations and the spectrum of a graph

It is shown that the intersection numbers of a coherent configuration are closely related to the determinant of a generic matrix for the corresponding adjacency algebra. This is important as both concepts provide isomorphism invariants for graphs.