A portfolio theory approach to crop planning under environmental constraints

This paper presents a multiobjective model for crop planning in agriculture. The approach is based on portfolio theory. The model takes into account weather risks, market risks and environmental risks. Input data include historical land productivity data for various crops, soil types and yield response to fertilizer/pesticide application. Several environmental levels for the application of fertilizers/pesticides, and the monetary penalties for overcoming these levels, are also considered. Starting from the multiobjective model we formulate several single objective optimization problems: the minimum environmental risk problem, the maximum expected return problem and the minimum financial risk problem. We prove that the minimum environmental risk problem is equivalent to a mixed integer problem with a linear objective function. Two numerical results for the minimum environmental risk problem are presented.     

The effect of gamma de-excitation competition on the (α, n) and (α, 2n) reactions on gold and antimony

Absolute cross sections for P¹⁹⁷Au(α, n)²⁰⁰Tl ¹⁹⁷Au(α, 2n)¹⁹⁹Tl, ¹²¹Sb(α, n)¹²⁴I and ¹²¹Sb(α, 2n)¹²³I are measured in the energy range from threshold to 27 Me V.The experimental results are interpreted in terms of evaporation statistical theory, including gamma de-excitation. The values of the level density parameters and of the average γ-ray strength for the compound systems are extracted.     

Natriumchlorit als Oxydationsmittel in der quantitativen analytischen Chemie

Zusammenfassung Es wird eine photocolorimetrische Methode zur Bestimmung von Atebrin mit Natriumchlorit bei pH 5,5–6 ( _max=485 nm) beschrieben. Das Lambert-Beersche Gesetz wird zwischen den Konzentrationsgrenzen 0,2 und 1,4 mg/10 ml befolgt. Die Methode wurde sowohl für reines Atebrin als auch für Atebrintabletten angewandt.

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Summary Sodium chlorite has been employed as a reagent for the photocolorimetric determination of atebrin (pH 5.5–6, _max=485 nm). Lambert-Beers's law is obeyed within the range of 0.2 to 1.4 mg/10 ml. The method has been applied to pure atebrin and to atebrin tablets.

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VI. Mitt.: Spacu, P., C. Gheorghiu u. I. Paralescu: diese Z. 195, 321 (1963).