Improvements in microphotometry by digital signal processing

From noise measurements with a microscope photometer it is deduced that the square roots of the measured intensities are linear with respect to photon noise. It is demonstrated by using a cytological specimen with a large dynamic range of intensities, that an IIR filter uniformly smoothes the square roots of the intensities, whereas the effect of that filter on the measured intensities is larger in dark parts of the image than in bright areas.     

Die Umströmung einer sich frei bewegenden Kugel in einem rotierenden Fluid

Zusammenfassung Es wird die Umstr?mung einer Kugel behandelt, die sich frei durch starr rotierendes Wasser bewegt. Auf experimentellem Weg wird gezeigt, da? das Gebiet in dem sich die Kugelbewegung bemerkbar macht, offensichtlich eine kegelartige Form mit ellipsen?hnlichem Querschnitt hat. Der Winkel des Kegels scheint linear von der Rossbyzahl abzuh?ngen. W?hrend die l?ngere Ellipsenachse linear w?chst, erreicht die kurze Achse rasch einen Wert von etwa fünf Kugeldurchmessern, der dann nicht weiter anw?chst. Vergleiche mit Kugelbewegungen in nicht rotierenden Fluiden zeigen, da? die beobachtete Umstr?mung wesentlich von der Rotation des Wassers beeinflu?t wird. Diese Arbeit entstand mit finanzieller F?rderung durch die Deutsche Forschungsgemeinschaft am Hermann-F?ttinger-Institut der Technischen Universit?t Berlin.     

On the paging-complexity of periodic arrangements

A simple model of a paging-system is investigated. The importance of the concept of pagination is stressed. The page-reference-strings under consideration stem from paginating simple loops, i.e. periodic sequences of consecutively accessed addresses. These reference strings are called periodic arrangements. The main objectives are: firstly, to prove a locality principle for this type of program structure: Given a pagination, generate as many references as possible to the same page in order to minimize page-traffic! Secondly, to show that this optimizing principle only holds for certain types of paging-algorithms, like Belady's algorithm and FIFO. It does no longer hold for the widely used paging-algorithm LRU, for instance.     

Suitability of instrumental analysis for the discrimination between wild-caught and conventionally and organically farmed shrimps

Shrimps, primarily Penaeus monodon and Litopenaeus vannamei, from organic and conventional farms and free-living stocks were purchased from the German market over 1 year. This study examined the applicability of established analytical methods for the confirmation of the correct labelling of shrimp products. After species identification of 77 shrimp products, the proximate composition, carotenoid pattern, fatty acid profile and stable isotopes of carbon and nitrogen in the lipids and/or the defatted dry matter (DDM) were determined. To differentiate between the three types of production (wild, organically farmed or conventionally farmed), parameters alone or in combination, partly derived by multivariate tests, were considered. Stable isotope ratio mass spectrometry allowed the differentiation between organically and conventionally farmed Litopenaeus vannamei using the combination of ?δ¹³C and δ¹⁵N_DDM values. The gas chromatographic analysis of fatty acids also distinguished between organically and conventionally farmed shrimp of this species. The ratio of the free astaxanthin configurational isomers in shrimp flesh, analysed by high-performance liquid chromatography (HPLC), was inadequate for any assignment, because of the apparent ability to alter the structure of the ingested carotenoids. Thus, a general differentiation of the three production types, irrespective of individual species, could not be achieved by any single method.     

Probing the nanoscale phase separation and photophysics properties of low-bandgap polymer:fullerene blend film by near-field spectroscopic mapping

The effect of the additive 1,8-octanedithiol (ODT) on the nanometer-scale morphology and local photophysical properties of low-bandgap polymer blends of poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b'] dithiophene)- alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) and [6,6]-phenyl C(61) -butyric acid methyl ester (PCBM) is investigated. Phase separations of the PCPDTBT:PCBM blend film induced by ODT are visualized by the morphological changes from fibril-shaped features to spherical bumps, by the dramatically increased photoluminescence emission from PCPDTBT that was originally largely quenched, and by the fluctuations of spectral features at different locations of the sample surface. The correlations between the morphology and the local photophysical properties of the blend film with/without ODT at both the micrometer and nanometer scales are revealed by confocal and high-resolution near-field spectroscopic mapping techniques.