Vorkommen und quantitative Bestimmung der Milchs?ure im Wein

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Interior of nonuniform black strings

We consider nonuniform black strings inside their event horizon. We present numerical evidence, that the singularity touches the horizon as the horizon topology changing transition is reached.     

Rotating black holes in dilatonic Einstein-Gauss-Bonnet theory

We construct generalizations of the Kerr black holes by including higher-curvature corrections in the form of the Gauss-Bonnet density coupled to the dilaton. We show that the domain of existence of these Einstein-Gauss-Bonnet-dilaton (EGBD) black holes is bounded by the Kerr black holes, the critical EGBD black holes, and the singular extremal EGBD solutions. The angular momentum of the EGBD black holes can exceed the Kerr bound. The EGBD black holes satisfy a generalized Smarr relation. We also compare their innermost stable circular orbits with those of the Kerr black holes and show the existence of differences which might be observable in astrophysical systems.     

Green synthesis of para-Menthane-3,8-diol from Eucalyptus citriodora: Application for repellent products

A simple and efficient method was developed for the synthesis of para-Menthane-3,8-diol (PMD), a well-known repellent active against mosquitoes, from Eucalyptus citriodora essential oil by a treatment of citric acid in a biphasic medium (H₂O/essential oil). The E. citriodora contains as main component (+)-citronellal (74% in the present case), which cyclises (Prins reaction) to form cis/trans PMD isomers. As an example, an emulsion containing an aqueous solution of 7% citric acid and E. citriodora oil at 50°, conducted after 15 h stirring to 82% conversion of (+)-citronellal with a selectivity of 80% with the remaining presence of monoterpenes and sesquiterpenes in the medium. Investigations of lasting protection on human volunteers are carried out using a cage test bioassay protocol and Aedes aegypti mosquitoes. At 20% in ⁱPrOH, the new reaction mixture showed a complete protection of 303 min compared to 22 min with the pure essential oil. The modified oil was compared with N,N-diethyl-m-methylbenzamide (DEET), the most popular active used in repellent formulations. Thermogravimetric analyses (TGA) of E. citriodora, the modified oil, PMD, DEET, and (+)-citronellal were performed and showed a slow evaporation rate for PMD and DEET as well as for the modified oil, which may explain their long lasting protection action.     

Surface orbital magnetism

We compute the surface correction to the density of states of a particle in a convex box subjected to a magnetic field. Applying these results to orbital magnetism, we find that at high temperatures or weak magnetic fields the surface magnetization is always paramagnetic, but oscillations appear at low temperatures. In two dimensions they can give very large paramagnetic contributions near integer values of the filling factor. Explicit formulas are given for the zero-field susceptibility and for samples with a cylindrical shape in arbitrary magnetic field.     

Visualization of competitive market structure by means of choice data

This paper presents a method for visualizing competitive market structures based on scanner panel data where asymmetries are taken into account. For this, I combined consumer choice models based on mixed logit models with three-mode principal component analysis. This approach can be used to unfold a competitive market structure map. The methodology presented is able to quantify the clout and receptivity of various brands. The results can then be visualized over time. Using this approach, guidelines for promotional activities of new brands can be provided, and possible threats from the competition detected.