Inaug.-dis.--Heidelberg. / Lebenslauf. "Anhang. Verzeichnis der mittleren örter von 88 fixsternen für 1900.0": p. [55]-63.

In 1968, Finson and Probstein outlined a theory which could be used to analyse cometary dust tails. This theory is applied to a series of P/Halley images, obtained using the UK Schmidt Telescope. The theory is successful and shows that P/Halley underwent a series of major outbursts during early 1986. The duration of the outbursts is approximately 2 days. This value coincides with the 2.2day nuclear rotation period, estimated by other observers. The size of the dust grains varies from submicron to several hundred microns and their calculated orbital parameters indicate that a considerable fraction of the larger grains contibute to the Zodiacal Dust Cloud. A range of CCD and UK Schmidt images reveal dust features in the comae of comets P/Crommelin, P/Giacobini-Zinner and P/Halley. Intensity contours for many images exhibited a "swinging round" effect i.e. for each image there was a systematic change in the photometric axis from the central condensation outwards. This was attributed to radiation pressure effects. Astrometric images of P/Halley show sharp parabolic hoods. These hoods are discussed with reference to near-nuclear dust grain orbits. Preliminary results indicate that the rotation period of Hailey is at least a few days. Mie (1908), developed a method by which the general properties of scattering and emission by dust grains, can be used to model cometary thermal spectra. Such a method is applied to several P/Halley spectra, taken during April, 1986. The results indicate that the dust grains could be composed of both an absorbing (e.g. magnetite) and a dielectric (e.g. silicate) material. The interrelations between decaying comets and Earth-crossing asteroids are discussed. Optical and infrared observations indicate that comet P/Neujmin 1 may be a transitionary object. P/Arend-Rigaux however, is still very active, displaying a large dust coma, with anisotropic emission.

No description available.

Ulm, Univ. Diss., 2006.

Ulm, Univ., Diss., 2009.

Thesis (Ph. D.)--University of Pennsylvania, 1910. / Describes the comet discovered in October 1898 by W.R. Brooks. This comet is also known as C/1898 U1. It is not the same as the "Brooks 2 Comet" that was discovered in July 1889.

Thesis (Ph. D.)--Johns Hopkins University, 1892. / Biography.

Thesis (Ph. D.)--Johns Hopkins University, 1892. / Biography.

Thesis (Ph. D.)--University of Pennsylvania, 1910. / Describes the comet discovered in October 1898 by W.R. Brooks. This comet is also known as C/1898 U1. It is not the same as the "Brooks 2 Comet" that was discovered in July 1889.

No / Human biomonitoring studies aim to identify potential exposures to environmental, occupational, or lifestyle toxicants in human populations and are commonly used by public health decision makers to predict disease risk. The Comet assay measures changes in genomic stability and is one of the most reliable biomarkers to indicate early biological effects, and therefore accepted by various governmental regulatory agencies. The appeal of the Comet assay lies in its relative simplicity, rapidity, sensitivity, and economic efficiency. Furthermore, the assay is known for its broad versatility, as it can be applied to virtually any human cell and easily adapted in order to detect particular biomarkers of interest, such as DNA repair capacity or single- and double-strand breaks. In a standard experiment, isolated single cells are first embedded in agarose, and then lysed in high-salt solutions in order to remove all cellular contents except the DNA attached to a nuclear scaffold. Subsequent electrophoresis results in accumulation of undamaged DNA sequences at the proximity of the nuclear scaffold, while damaged sequences migrate towards the anode. When visualized with fluorochromes, these migrated DNA fragments resemble a comet tail and can be quantified for their intensity and shape according to internationally drafted guidelines.