Texturerkennung und texturreproduktion

Computer generated textures are used to examine the recognition of pictorial textures and their edges by supervised learning. Since the recognition of texture at a given spot of the image involves measurements within a certain neighborhood of this spot, misclassification occurs at the edge between different textures, as was shown in Part 1. The edge enhancement procedures do also not produce a sharp edge. Based on some psychooptical evidence, a propagation operator is utilized to define the edges. First, the textures are classified only in those regions where a high level of confidence exists, the rest of the picture being marked as unrecognized. Second, the unrecognized picture elements adjoining a recognized spot are given its class, thus enlarging the recognized area. This process is repeated a few times, the limit being the propagation of results over an area greater than the neighborhood within which the texture parameters were measured in the first instance. The procedure yields welldefined edges at the proper locations.     

The Effects of Chilling on the Fecundity and Life Span of Mass-reared Parasitoids (Hymenoptera: Braconidae) of the Mediterranean Fruit Fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

Suppression of Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), populations may be achieved through the mass-rearing and augmentative aerial release of opiine braconid parasitoids. Typically, aerial release techniques require up to one hour of chilling of adult parasitoids at temperatures as low as 3.5°C prior to their dissemination. Such chilling potentially could affect the subsequent performance of the insects. Among three species of the genus Diachasmimorpha longicaudata (Ashmead), tryoni (Cameron), and krausii (Fullaway) there was little or no affect of chilling in the laboratory on female longevity, production of daughters, or offspring sex ratio. This is consistent with previous experiments that found chilling to have no discernable effect on the short-term mortality of D. tryoni or on its ability to take flight immediately after aerial release. While there was little effect of chilling on longevity and fecundity in a species from another opiine genus, Fopius arisanus (Sonan), exposure to low temperatures did result in a significantly more male-biased offspring sex ratio.     

Fluorescence resonance energy transfer reports properties of syntaxin1a interaction with Munc18-1 in vivo

Syntaxin1A, a neural-specific N-ethylmaleimide-sensitive factor attachment protein receptor protein essential to neurotransmitter release, in isolation forms a closed conformation with an N-terminal alpha-helix bundle folded upon the SNARE motif (H3 domain), thereby limiting interaction of the H3 domain with cognate SNAREs. Munc18-1, a neural-specific member of the Sec1/Munc18 protein family, binds to syntaxin1A, stabilizing this closed conformation. We used fluorescence resonance energy transfer (FRET) to characterize the Munc18-1/syntaxin1A interaction in intact cells. Enhanced cyan fluorescent protein-Munc18-1 and a citrine variant of enhanced yellow fluorescent protein-syntaxin1A, or mutants of these proteins, were expressed as donor and acceptor pairs in human embryonic kidney HEK293-S3 and adrenal chromaffin cells. Apparent FRET efficiency was measured using two independent approaches with complementary results that unambiguously verified FRET and provided a spatial map of FRET efficiency. In addition, enhanced cyan fluorescent protein-Munc18-1 and a citrine variant of enhanced yellow fluorescent protein-syntaxin1A colocalized with a Golgi marker and exhibited FRET at early expression times, whereas a strong plasma membrane colocalization, with similar FRET values, was apparent at later times. Trafficking of syntaxin1A to the plasma membrane was dependent on the presence of Munc18-1. Both syntaxin1A(L165A/E166A), a constitutively open conformation mutant, and syntaxin1A(I233A), an H3 domain point mutant, demonstrated apparent FRET efficiency that was reduced approximately 70% from control. In contrast, the H3 domain mutant syntaxin1A(I209A) had no effect. By using phosphomimetic mutants of Munc18-1, we also established that Ser-313, a Munc18-1 protein kinase C phosphorylation site, and Thr-574, a cyclin-dependent kinase 5 phosphorylation site, regulate Munc18-1/syntaxin1A interaction in HEK293-S3 and chromaffin cells. We conclude that FRET imaging in living cells may allow correlated regulation of Munc18-1/syntaxin1A interactions to Ca(2+)-regulated secretory events.     

Zur Analyse der VitalfÄrbung in Gegenwart von HuminsÄure

Ohne Zusammenfassung     

Schweizerische Vegetationsforschung von 1938 bis 1948

Ohne ZusammenfassungManuskript eingegangen am 27.X.1949.