Could a different management routine that strengthens the mother-offspring bond contribute to a more efficient organic piglet production?

In current Swedish organic piglet production full reproductive potential of the sows and growth potential of piglets are not achieved. The efficiency is held back by occurrence of lactational oestrus, low litter weight and large weight variation within litter. Therefore it is critical that these obstacles are reduced in a way that is easy to adapt in practice and does not contradict the ideas behind organic animal husbandry. This project aims to an improvement of the conditions needed to efficiently produce organic piglets in a batch wise manner. The batch wise breeding will reduce production costs and increase disease control. Our preliminary results indicate that the sow’s weaning to oestrus interval can be affected by the time spent in individual farrowing pen during the lactational period

Thomas-Fermi-Dirac-von Weizsacker hydrodynamics in laterally modulated electronic systems

We have studied the collective plasma excitations of a two-dimensional electron gas with an arbitrary lateral charge-density modulation. The dynamics is formulated using a previously developed hydrodynamic theory based on the Thomas-Fermi-Dirac-von Weizsacker approximation. In this approach, both the equilibrium and dynamical properties of the periodically modulated electron gas are treated in a consistent fashion. We pay particular attention to the evolution of the collective excitations as the system undergoes the transition from the ideal two-dimensional limit to the highly-localized one-dimensional limit. We also calculate the power absorption in the long-wavelength limit to illustrate the effect of the modulation on the modes probed by far-infrared (FIR) transmission spectroscopy.Comment: 27 page Revtex file, 15 Postscript figure

Magnetoplasmon excitations in an array of periodically modulated quantum wires

Motivated by the recent experiment of Hochgraefe et al., we have investigated the magnetoplasmon excitations in a periodic array of quantum wires with a periodic modulation along the wire direction. The equilibrium and dynamic properties of the system are treated self-consistently within the Thomas-Fermi-Dirac-von Weizsaecker approximation. A calculation of the dynamical response of the system to a far-infrared radiation field reveals a resonant anticrossing between the Kohn mode and a finite-wavevector longitudinal excitation which is induced by the density modulation along the wires. Our theoretical calculations are found to be in excellent agreement with experiment.Comment: 9 pages, 8 figure

Magnetoplasmon excitations in arrays of circular and noncircular quantum dots

We have investigated the magnetoplasmon excitations in arrays of circular and noncircular quantum dots within the Thomas-Fermi-Dirac-von Weizs\"acker approximation. Deviations from the ideal collective excitations of isolated parabolically confined electrons arise from local perturbations of the confining potential as well as interdot Coulomb interactions. The latter are unimportant unless the interdot separations are of the order of the size of the dots. Local perturbations such as radial anharmonicity and noncircular symmetry lead to clear signatures of the violation of the generalized Kohn theorem. In particular, the reduction of the local symmetry from SO(2) to $C_4$ results in a resonant coupling of different modes and an observable anticrossing behaviour in the power absorption spectrum. Our results are in good agreement with recent far-infrared (FIR) transmission experiments.Comment: 25 pages, 6 figures, typeset in RevTe

Role of phason-defects on the conductance of a 1-d quasicrystal

We have studied the influence of a particular kind of phason-defect on the Landauer resistance of a Fibonacci chain. Depending on parameters, we sometimes find the resistance to decrease upon introduction of defect or temperature, a behavior that also appears in real quasicrystalline materials. We demonstrate essential differences between a standard tight-binding model and a full continuous model. In the continuous case, we study the conductance in relation to the underlying chaotic map and its invariant. Close to conducting points, where the invariant vanishes, and in the majority of cases studied, the resistance is found to decrease upon introduction of a defect. Subtle interference effects between a sudden phason-change in the structure and the phase of the wavefunction are also found, and these give rise to resistive behaviors that produce exceedingly simple and regular patterns.Comment: 12 pages, special macros jnl.tex,reforder.tex, eqnorder.tex. arXiv admin note: original tex thoroughly broken, figures missing. Modified so that tex compiles, original renamed .tex.orig in source

A multi-instrument comparison of integrated water vapour measurements at a high latitude site

We compare measurements of integrated water vapour (IWV) over a subarctic site (Kiruna, Northern Sweden) from five different sensors and retrieval methods: Radiosondes, Global Positioning System (GPS), ground-based Fourier-transform infrared (FTIR) spectrometer, groundbased microwave radiometer, and satellite-based microwave radiometer (AMSU-B). Additionally, we compare also to ERA-Interim model reanalysis data. GPS-based IWV data have the highest temporal coverage and resolution and are chosen as reference data set. All datasets agree reasonably well, but the ground-based microwave instrument only if the data are cloud-filtered. We also address two issues that are general for such intercomparison studies, the impact of different lower altitude limits for the IWV integration, and the impact of representativeness error. We develop methods for correcting for the former, and estimating the random error contribution of the latter. A literature survey reveals that reported systematic differences between different techniques are study-dependent and show no overall consistent pattern. Further improving the absolute accuracy of IWV measurements and providing climate-quality time series therefore remain challenging problems

Incidence of Lower-Limb Amputation in the Diabetic and Nondiabetic General Population: A 10-year population-based cohort study of initial unilateral and contralateral amputations and reamputations

OBJECTIVE—The purpose of this study was to compare the incidence of vascular lower-limb amputation (LLA) in the diabetic and nondiabetic general population

Dynamics in Colloidal Liquids near a Crossing of Glass- and Gel-Transition Lines

Within the mode-coupling theory for ideal glass-transitions, the mean-squared displacement and the correlation function for density fluctuations are evaluated for a colloidal liquid of particles interacting with a square-well potential for states near the crossing of the line for transitions to a gel with the line for transitions to a glass. It is demonstrated how the dynamics is ruled by the interplay of the mechanisms of arrest due to hard-core repulsion and due to attraction-induced bond formation as well as by a nearby higher-order glass-transition singularity. Application of the universal relaxation laws for the slow dynamics near glass-transition singularities explains the qualitative features of the calculated time dependence of the mean-squared displacement, which are in accord with the findings obtained in molecular-dynamics simulation studies by Zaccarelli et. al [Phys. Rev. E 66, 041402 (2002)]. Correlation functions found by photon-correlation spectroscopy in a micellar system by Mallamace et. al [Phys. Rev. Lett. 84, 5431 2000)] can be interpreted qualitatively as a crossover from gel to glass dynamics.Comment: 13 pages, 12 figure

Edge and bulk effects in the Terahertz-photoconductivity of an antidot superlattice

We investigate the Terahertz(THz)-response of a square antidot superlattice by means of photoconductivity measurements using a Fourier-transform-spectrometer. We detect, spectrally resolved, the cyclotron resonance and the fundamental magnetoplasmon mode of the periodic superlattice. In the dissipative transport regime both resonances are observed in the photoresponse. In the adiabatic transport regime, at integer filling factor $\nu =2$, only the cyclotron resonance is observed. From this we infer that different mechanisms contribute to converting the absorption of THz-radiation into photoconductivity in the cyclotron and in the magnetoplasmon resonances, respectively.Comment: 15 pages, 4 figures, submitted to Phys. Rev.

Scalar quantum kinetic theory for spin-1/2 particles: mean field theory

Starting from the Pauli Hamiltonian operator, we derive a scalar quantum kinetic equations for spin-1/2 systems. Here the regular Wigner two-state matrix is replaced by a scalar distribution function in extended phase space. Apart from being a formulation of principal interest, such scalar quantum kinetic equation makes the comparison to classical kinetic theory straightforward, and lends itself naturally to currently available numerical Vlasov and Boltzmann schemes. Moreover, while the quasi-distribution is a Wigner function in regular phase space, it is given by a Q-function in spin space. As such, nonlinear and dynamical quantum plasma problems are readily handled. Moreover, the issue of gauge invariance is treated. Applications (e.g. ultra-dense laser compressed targets and their diagnostics), possible extensions, and future improvements of the presented quantum statistical model are discussed.Comment: 21 pages, 2 figure