Herzfrequenzen im Melkstand von konventionell und muttergebunden aufgezogenen Färsen

The aim of this study was to evaluate the influence of the rearing method on heart rates (as stress indicator) in the first days of lactation during milking. Heart rate was measured in two cows (K) and in eight heifers, four (F) reared with an automatic teat feeder, four (FKK) reared naturally by suckler- or foster cows. Heart rate was evaluated with a POLAR heart rate monitor on day one and nine of lactation during the milking procedure. The respective heart rates could be assigned to the events in the milking parlour via videoanalysis. Between the two heifer groups there were no physiologically relevant differences in heart rates on the two observed days. Both heifer groups showed higher heart rates on day one compared with day nine. Group K showed lower heart rates on both days

Evaporation of buffer gas-thermalized anions out of a multipole rf ion trap

We identify plain evaporation of ions as the fundamental loss mechanism out of a multipole ion trap. Using thermalized negative Cl- ions we find that the evaporative loss rate is proportional to a Boltzmann factor. This thermodynamic description sheds new light on the dynamics of particles in time-varying confining potentials. It specifically allows us to extract the effective depth of the ion trap as the activation energy for evaporation. As a function of the rf amplitude we find two distinct regimes related to the stability of motion of the trapped ions. For low amplitudes the entire trap allows for stable motion and the trap depth increases with the rf field. For larger rf amplitudes, however, rapid energy transfer from the field to the ion motion can occur at large trap radii, which leads to a reduction of the effective trapping volume. In this regime the trap depth decreases again with increasing rf amplitude. We give an analytical parameterization of the trap depth for various multipole traps that allows predictions of the most favorable trapping conditions.Comment: Phys. Rev. Lett., in pres

Strange eigenstates and anomalous transport in a Koch fractal with hierarchical interaction

Stationary states of non-interacting electrons on a Koch fractal are investigated within a tight binding approach. It is observed that if a hierarchically long range hopping is allowed, a suitable correlation between the parameters defining the Hamiltonian leads to spectacular changes in the transport properties of finite, but arbitrarily large fractals. Topologically identical structures, that are found to support the same distribution of the amplitudes of eigenstates, are conducting in some cases and insulating in the others, depending on the choice of the hierarchy parameter. The values of the hierarchical parameter themselves display a self-similar, fractal character.Comment: 6 pages, 5 figure

Anatomy of three-body decay I. Schematic models

Sequential three-body decay proceeds via spatially confined quasi-stationary two-body configurations. Direct three-body decay populates the three-body continuum without intermediate steps. The relative importance of these decay modes is discussed in a schematic model employing only Coulomb or centrifugal barrier potentials. Decisive dimensionless charge, mass and energy ratios are derived. Sequential decay is usually favored for charged particles. Small charge and small mass of high energy is preferably emitted first. Without Coulomb potential the sequential decay is favored except when both resonance energy and intermediate two-body energy are large.Comment: To be published in Nuclear Physics

Bremsstrahlung in alpha-Decay Reexamined

A high-statistics measurement of bremsstrahlung emitted in the alpha decay of 210Po has been performed, which allows to follow the photon spectra up to energies of ~ 500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasi classical approximation as well as with the exact quantum mechanical calculation. It is shown that due to the small effective electric dipole charge of the radiating system a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the alpha particle and the emitted photon.Comment: 10 pages, 5 figures, v2: fix of small typo

Potential and limitations of nucleon transfer experiments with radioactive beams at REX-ISOLDE

As a tool for studying the structure of nuclei far off stability the technique of gamma-ray spectroscopy after low-energy single-nucleon transfer reactions with radioactive nuclear beams in inverse kinematics was investigated. Modules of the MINIBALL germanium array and a thin position-sensitive parallel plate avalanche counter (PPAC) to be employed in future experiments at REX-ISOLDE were used in a test experiment performed with a stable 36S beam on deuteron and 9Be targets. It is demonstrated that the Doppler broadening of gamma lines detected by the MINIBALL modules is considerably reduced by exploiting their segmentation, and that for beam intensities up to 10^6 particles/s the PPAC positioned around zero degrees with respect to the beam axis allows not only to significantly reduce the gamma background by requiring coincidences with the transfer products but also to control the beam and its intensity by single particle counting. The predicted large neutron pickup cross sections of neutron-rich light nuclei on 2H and 9Be targets at REX-ISOLDE energies of 2.2 MeV A are confirmed.Comment: 11 pages, 8 figure

A renormalisation approach to excitable reaction-diffusion waves in fractal media

Of fundamental importance to wave propagation in a wide range of physical phenomena is the structural geometry of the supporting medium. Recently, there have been several investigations on wave propagation in fractal media. We present here a renormalization approach to the study of reaction-diffusion (RD) wave propagation on finitely ramified fractal structures. In particular we will study a Rinzel-Keller (RK) type model, supporting travelling waves on a Sierpinski gasket (SG), lattice

Berührungsloses Fiebermessen bei Ziegen durch elektronische Tierkennzeichnung– geht das?

Ziel dieser Studie war die Überprüfung in wiefern sich zwei unterschiedliche Applikationsorte für eine subkutane Körpertemperaturmessung bei Ziegen eignen. Damit könnte die elektronische Tierkennzeichnung zur Krankheitsfrüherkennung und damit für die Tiergesundheit genutzt werden. Die eingesetzte Antenne war für die Erfassung der Körpertemperatur nicht geeignet, weil die Schwanzfalte belüftet wurde. Statt dieser Antenne wurde in den folgenden Versuchen ein Stick-Reader eingesetzt

On the extendedness of eigenstates in a hierarchical lattice: a critical view

We take a critical view at the basic definition of extended single particle states in a non-translationally invariant system. For this, we present the case of a hierarchical lattice and incorporate long range interactions that are also distributed in a hierarchical fashion. We show that it is possible to explicitly construct eigenstates with constant amplitudes (normalized to unity) at every lattice point for special values of the electron- energy. However, the end-to-end transmission, corresponding to the above energy of the electron in such a hierarchical system depends strongly on a special correlation between the numerical values of the parameters of the Hamiltonian. Keeping the energy and the distribution of the amplitudes invariant, one can transform the lattice from conducting to insulating simply by tunning the numerical values of the long range interaction. The values of these interactions themselves display a fractal character.Comment: 19 pages, 5 figure