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Biomedical subjects

H J Hamann

Publications and source records attributed to H J Hamann.

15 recordsLinked to original sources
PubMed2000

A GPS-based system for recording the flight paths of birds.

The GPS recorder consists of a GPS receiver board, a logging facility, an antenna, a power supply, a DC-DC converter and a casing. Currently, it has a weight of 33 g. The recorder works reliably with a sampling rate of 1/s and with an operation time of about 3 h, providing time-indexed data on geographic positions and ground speed. The data are downloaded when the animal is recaptured. Prototypes were tested on homing pigeons. The records of complete flight paths with surprising details illustrate the potential of this new method that can be used on a variety of medium-sized and large vertebrates.

Aircraft↗
PubMed1981

Radiochemically determined trace element contents of pig's and cow's blood used in membrane feeding of tsetse flies.

Blood of pigs and cows from Langford/Bristol (U.K.) and Hannover (F.R.G.) used in membrane feeding of tsetse flies was analysed for 21 trace elements; an influence of the location of origin was not detectable. Between the two host species a significant difference of the element content was established for bromine, copper, rubidium, and zinc; if this observation is responsible for the different nutritive value of pig's and cow's blood it cannot be identified from the present experiment.

Animals↗
PubMed1975

[Separation of the effects of transmutation and radiation after incorporation of radionuclides into DNA (author's transl)].

Among the various methods for studying the relative effects of transmutation and radiation of incorporated nuclides, simulation of beta radiation by external gamma exposure is of practical importance. Self-irradiation and mutual irradiation of the labeled cells cannot be neglected in any case. Furthermore, additional hypothetical and experimental problems may arise from using either external beta radiation or different isotopes of an element. By means of external gamma irradiation on the other hand, this being equivalent to the internal beta radiation from a microdosimetrical point of view, the radiation effect of the nuclide alone can be observed without any modification of other experimental parameters. To determine such equivalent gamma radiation for labeled cell nuclei of Vicia faba roots, the authors applied the Monte Carlo Method to the beta spectra of 32-P, 3-H, 14-C and 131-J, to the energy-dependent LET and to different cell diameters. The existence of secondary particle equilibrium inside the nuclei during gamma exposure was assumed. For certain radionuclides and cell sizes it is possible to calculate gamma spectra which induce energy spectra in the nuclei similar to those caused by the beta particles originating in the nuclear DNA.

Carbon Radioisotopes↗