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Extending the GGobi pipeline from R

This paper describes progress towards developing a platform for rapid prototyping of interactive data visualizations, using R, GGobi, rggobi and RGtk2. GGobi is a software tool for multivariate interactive graphics. At the core of GGobi is a data pipeline that incrementally transforms data through a series of stages into a plot and maps user interaction with the plot back to the data. The GGobi pipeline is extensible and mutable at runtime. The rggobi package, an interface from the R language to GGobi, has been augmented with a low-level interface that supports the customization of interactive data visualizations through the extension and manipulation of the GGobi pipeline. The large size of the GGobi API has motivated the use of the RGtk2 code generation system to create the low-level interface between R and GGobi. The software is demonstrated through an application to interactive network visualization.     

Groupwise dense families

We show that the Filter Dichotomy Principle implies that there are exactly four classes of ideals in the set of increasing functions from the natural numbers. We thus answer two open questions on consequences of ? < ?. We show that ? < ? implies that ? = ?, and that Filter Dichotomy together with ? < ? implies ? < ?. The technical means is the investigation of groupwise dense sets, ideals, filters and ultrafilters. With related techniques we prove the new inequality ?≤ cf(?). Received: 9 October 1998 / Revised version: 18 August 1999 / Published online: 21 December 2000     

Zur quantitativen Bestimmung des Glycerins im Weine

Ohne Zusammenfassung     

Methode zur Bestimmung der Gesammtmenge der fixen Harnbestandtheile

Ohne ZusammenfassungWiesbaden, den 27, Januar 1862.     

Control of charge transfer by conformational and electronic effects: Donor–donor and donor–acceptor phenyl pyrroles

Derivatives of N-pyrrolobenzene with a para-donor and a para-acceptor substituent on the benzene ring are compared. It is shown that by a suitable increase of the donor strength of the pyrrolo group, CT fluorescence can be achieved even for donor–donor-substituted benzenes. The ICT emission for sterically hindered compounds is more forbidden than that of unhindered phenyl pyrroles. This suggests conformational effects which induce a narrower twist angle distribution around a perpendicular minimum in the excited state.     

Heat treatment-induced bond layer diffusion and re-crystallization in copper carbon interface systems measured by modulated IR radiometry

Copper-carbon interface systems with additional Mo bond layers in the range of 25 nm to 200 nm have been analyzed with respect to their effective thermal depth profiles before and after heat treatment using modulated IR radiometry. Comparing the inverse calibrated modulated IR phase lags before and after heat treatment, several effects can be identified: – (1) The effusivity of the interface layer, which – due the contact resistance between the two elements copper and carbon – is rather low before heat treatment, increases considerably with heat treatment. – (2) This effect is accompanied by an increase of the thermal diffusion time of the interface layer, relying on the diffusion of Mo and Cu particles. – (3) The sputter-deposited copper films, which before heat treatment can be characterized as effective multi-layer structures, re-crystallize with heat treatment and show modulated IR phases, which are characteristic for thermally homogeneous thin films. – (4) The thermal diffusion times of the Cu films decrease considerably with heat treatment due to increased thermal diffusivities, and – (5) the thermal effusivities of the Cu films increase with heat treatment.     

Electrochemical Assay to Quantify the Hydroxyl Radical Scavenging Activity of Medicinal Plant Extracts

A new electrochemical assay has been developed which is based on quantifying the attack of OH^. radicals on a self‐assembled thiol monolayer on electrodes in the presence and absence of antioxidants. The OH^. radicals were produced in Fenton solutions. The radical scavengers diminish the concentration of the OH^. radicals in the Fenton solution, and the extent of thiol layer destruction is monitored with the help of a redox probe in solution, the signal of which is only generated at SAM‐free electrode surface. The results of the electrochemical assay were compared with those of the standard DPPH^. assay. In case of each plant extract, an excellent linear correlation was observed between the radical scavenging activity and the concentration of plant extracts; however, the scavenging properties of different plants strongly differ in the electrochemical and the DPPH^. assay. Since the proposed new method probes the reactivity of radical scavengers towards OH^., one of the most important reactive oxygen radicals in tissues, it is supposed to provide much more relevant information than the DPPH^. or other assays.