Outer product analysis of electronic nose and visible spectra: application to the measurement of peach fruit characteristics

Visual aspect and aroma are among the most important features of fruit that determine consumer preferences. Electronic nose and spectroscopic techniques have shown positive results in evaluating some basic analytical parameters of fruit and global features such as the cultivar.In this paper, we illustrate and discuss a study aimed at evaluating the improvement derived by the fusion of visible spectra and electronic nose data. These experiments were performed on a population of yellow peaches belonging to two cultivars. Each sample was measured by visible optical spectroscopy and by electronic nose. In addition, a number of reference parameters were also measured by conventional destructive methodologies.Collected data were analysed individually and then fused together in order to classify the two cultivars and to estimate the reference parameters. Data fusion was performed building the outer product matrix for each measurement. The set of matrices was then successively unfolded and analysed by conventional chemometrics tools.Results were improved using outer products, for instance in classification average percentage errors of 25, 10, and 7 for electronic nose, spectra, and outer product, respectively was achieved. Regression analysis provides the evidence of a substantial orthogonal appearance of the datasets, which offer former hidden information on fruit classification.     

Structural studies of 4-aryloctahydro-pyrido[1,2-c]pyrimidine derivatives

¹³C cross-polarisation magic angle spinning NMR data have been reported for four derivatives of 4-aryl-octahydro-pyrido[1,2-c]pyrimidine-1,3-dione and the X-ray diffraction data for two (with 2′-Me and 2′-OMe). The crystal structures show the presence of centrosymmetric cyclic dimers with intermolecular C1O?H-N or C3O?H-N hydrogen bonds, the configuration at the chiral centres (C4 and C4_a) was determined as RR (SS). The twisting of aromatic ring at C4 with respect to the pyrido[1,2-c]pyrimidine skeleton is about 68-109°.     

Nullstellen von Real- und Imaginärteil der Lösungen linearer Differentialgleichungen 2. Ordnung

This paper is concerned with complex Sturmtype comparison theorems. Especially it is shown that the location of the zeros of a nontrivial solution of a second order linear differential equation with complex-valued coefficients gives information about the distribution of the zeros of the real and imaginary part of any solution of certain other complex second order linear differential equations.     

On-line monitoring of media components during the production of cephalosporin C

For optimum process management, substrates and products should be monitored continuously, because substrates are expensive, and because catabolic repression can be avoided. The main problem is continuous sampling. A cross-flow, hollow-fiber filtration module is described for the removal of solid-free samples from the high-solids medium required for cephalosporin-C production. The solids-free medium then permeates through a membrane, and is transported through air-segmented flow systems which quantify glucose (enzyme electrode), ammonia (ammonia-selective electrode), phosphate (molybdenum blue spectrophotometry), sulfate (methylthymol blue/barium), methionine (sodium nitroprusside) and cephalosporin (direct u.v. absorbance). The methods for glucose, methionine and cephalosporin are described in detail. The system is controlled by computer.     

?therische ?le

Ohne Zusammenfassung     

Slicing the Oppenheimer-Snyder Collapse: Harmonic versus Maximal Slicing

In continuing our studies of temporal slicings of spacetimes, we consider the collapse from rest of an initially homogeneous dust sphere, known as Oppenheimer-Snyder collapse. It is shown that in the case of harmonic slicing the whole spacetime becomes covered by slices extending to spatial infinity in contrast to maximal slicing. The behavior of the lapse function is discussed, especially for various data on the initial slice, and it is demonstrated that not every choice of the initial lapse leads to meaningful slicings.