The metabolism of fenazox in tomato plants

Results from investigations on the metabolism of 14C-Fenazox show that in 6-8 weeks old tomato-plants (sort "Harzfeuer") the agent undergoes a biotransformation. After chromatographic separation the structure of the biotransformation products was elucidated by comparison to authentic test substances, by derivatization as well as by means of physico-chemical methods. With that, the following metabolites were identified: non-transformed Fenazox, o-hydroxyazobenzene, o-hydroxyaniline, and p-hydroxyaniline. Probably, the agent is first transformed enzymatically or non-enzymatically into o-hydroxyazobenzene, then follows a reductive cleavage into o-hydroxyaniline and aniline. In its turn, the latter is transformed into o-hydroxy- and p-hydroxyaniline. Experiments in the field of transformation kinetics indicated that the concentration of the applied Fenazox rapidly decreases and that the first transformation product o-hydroxyazobenzene in the beginning increases and then again decreases in its concentration. With increasing application time it comes to an increase of the non-extractable residues.     

Magnetization and torque measurements on rotating niobium cylinders and ellipsoids

The magnetization and torque of niobium samples of different shapes rotating in a magnetic field are studied with emphasis on the behavior near the upper critical field H _c2. The observed rotational magnetization is free of hysteresis and is found to represent a good approximation to the thermodynamic equilibrium magnetization of the samples if pinning is not too strong and the frequency of rotation is sufficiently low. The viscous contribution to the torque exhibits a step at H _c2whose dependence on sample geometry is in good agreement with predictions derived under the simple assumption of a homogeneous arrangement of parallel straight vortices in the rotating sample.     

Evaluation of Crop Models for Simulating and Optimizing Deficit Irrigation Systems in Arid and Semi-arid Countries Under Climate Variability

The variability of fresh water availability in arid and semi-arid countries poses a serious challenge to farmers to cope with when depending on irrigation for crop growing. This has shifted the focus onto improving irrigation management and water productivity (WP) through controlled deficit irrigation (DI). DI can be conceived as a strategy to deal with these challenges but more knowledge on risks and chances of this strategy is urgently needed. The availability of simulation models that can reliably predict crop yield under the influence of soil, atmosphere, irrigation, and agricultural management practices is a prerequisite for deriving reliable and effective deficit irrigation strategies. In this context, this article discusses the performance of the crop models CropWat, PILOTE, Daisy, and APSIM when being part of a stochastic simulation-based approach to improve WP by focusing primarily on the impact of climate variability. The stochastic framework consists of: (i) a weather generator for simulating regional impacts of climate variability; (ii) a tailor-made evolutionary optimization algorithm for optimal irrigation scheduling with limited water supply; and (iii) the above mentioned models for simulating water transport and crop growth in a sound manner. The results present stochastic crop water production functions (SCWPFs) that can be used as basic tools for assessing the impact on the risk for the potential yield due to water stress and climate variability. Example simulations from India, Malawi, France and Oman are presented and the suitability of these crop models to be employed in a framework for optimizing WP is evaluated.     

The influence of the extraction voltage on the energetic electron population of an electron cyclotron resonance ion source plasma

An influence of the extraction voltage on the high energy slope of bremsstrahlung radiation spectra has been reported in ECRIS experiments, which is not well understood so far. In order to provide more detailed data on this effect, we have measured bremsstrahlung radiation spectra accompanying especially the evolution of highly charge ions (i.e., by monitoring the Ar(14+) charge state) as the extraction voltage is changed from 0 to 20 kV, in dedicated experiments at the Frankfurt 14 GHz-ECRIS.     

New method for selectivity enhancement of SiC field effect gas sensors for quantification of NO x

A silicon carbide based enhancement type metal insulator field effect transistor with porous gate metallization has been investigated as a total NO _x sensor operated in a temperature cycling mode. This operating mode is quite new for gas sensors based on the field effect but promising results have been reported earlier. Based on static investigations we have developed a suitable T-cycle optimized for NO _x detection and quantification in a mixture of typical exhaust gases (CO, C₂H₄, and NH₃). Significant features describing the shape of the sensor response have been extracted and evaluated with multivariate statistics (e.g. linear discriminant analysis) allowing quantification of NO _x . Additional cleaning-cycles every 30?min improve the stability of the sensor further. With this kind of advanced signal processing the influence of sensor drift and cross sensitivity to ambient gases can be reduced effectively. Measurements have proven that different concentrations of NO _x can be detected even in a changing mixture of other typical exhaust gases under dry and humid conditions. In addition to that, unknown concentrations of NO _x can be detected based on a small set of training data. It can be concluded that the performance of GasFETs for NO _x determination can be enhanced considerably with temperature cycling and appropriate signal processing.     

Cracking in and around the thermally grown oxide in thermal barrier coatings: A comparison of isothermal and cyclic oxidation

In the present paper the time and temperature dependent evolution of the microstructure of TBC systems and especially of post-experimentally determined physical defects in and around the TGO for both isothermal and cyclic exposure conditions are investigated. Specimens with APS- as well as with PVD-topcoats have been oxidised between 950 and 1100°C up to a maximum duration of 5000 h followed by extensive scanning electron microscopy and subsequent interactive image analysis to measure the maximum crack lengths in and around the TGO. These cracks are additionally classified with respect to their local orientation in the TGO or its vicinity. The results of isothermal and cyclic test conditions show a number of similarities in results e.g. an unsystematic occurrence of inwardly growing, “cauliflower like” oxide or the most frequently occurring type of cracks in APS systems. Nevertheless substantial differences concerning the final failure, microstructure, crack growth behaviour and finally life time of the component between isothermal and cyclic test conditions exist. Some indications were found, that for this particular bond coat occurance of inwardly growing oxide intrusions increases the adherence of the TGO.     

On a Kernel-Based Method for Pattern Recognition, Regression, Approximation, and Operator Inversion

We present a kernel-based framework for pattern recognition, regression estimation, function approximation, and multiple operator inversion. Adopting a regularization-theoretic framework, the above are formulated as constrained optimization problems. Previous approaches such as ridge regression, support vector methods, and regularization networks are included as special cases. We show connections between the cost function and some properties up to now believed to apply to support vector machines only. For appropriately chosen cost functions, the optimal solution of all the problems described above can be found by solving a simple quadratic programming problem. Received January 31, 1997; revised June 1, 1997, and July 7, 1997.     

„Medizinische Notwendigkeit“: Herausforderungen eines unscharfen Begriffs

Definition of the problem

“Medical necessity” (MedN) is the central regulatory concept for decisions about which services are covered by German statutory health insurance. Despite its seeming objectivity and dependence on physicians’ expert judgment, the concept is by no means clearly defined.

Arguments

In this first of five planned papers on the conceptual analysis of MedN from the perspectives of philosophy and ethics of medicine, law, and (social) medicine, the focus lies on systemizing ongoing controversies.

Conclusion

Our goal is to come up with a so far missing foundation for detailed debates. We aim to clarify MedN’s conceptual structure, function, contextuality, and ambiguities as well as the fundamental limits of conceptual investigations for the normative questions at issue of regulating medical services.

     

Software specification using graph grammars

The following paper demonstrates that programmed sequential graph grammars can be used in a systematic proceeding to specify the changes of high level intermediate data structures arising in a programming support environment, in which all tools work in an incremental and syntax-driven mode. In this paper we lay stress upon the way to get the specification rather than on the result of this process. Therefore, we give here some approach to “specification engineering” using graph grammars. This approach is influenced by the syntactical definition of the underlying language for Programming in the Small, the module concept etc. to be supported on one side but also by the idea of the user interface.     

Identification of chemical markers for the sensory shelf-life of saveloy

The aroma composition, the microbial composition and the sensory profile were measured in sliced saveloy samples packed in modified atmosphere (MA). The main objective was to identify aroma compounds with potential as chemical markers to identify the sensory changes of saveloy. The 60 aroma compounds isolated from the saveloy samples by dynamic headspace extraction and measured by Gas Chromatography Mass Spectrometry (GC-MS) were used to model the sensory attributes sour&old odour and meaty odour using partial least squares regression (PLS). 2- and 3-methylbutanal, 2- and 3-methylbutanol, acetoin and diacetyl were found to have the highest impact on both sour&old odour and meaty odour of the samples. The results show that these four aroma compounds have high potential as chemical markers for the sensory shelf-life of sliced and MA-packed saveloy.