Low stress and safe handling of outdoor cattle - effective measures to improve work environment and avoid dangerous situations

Grazing cattle are needed to preserve 450 000 hectares of semi-natural grasslands of high biodiversity in Sweden. Keeping cattle outdoors promotes their health and possibili¬ties to conduct natural behaviors. Working with cattle on pasture however, can increase accident rates (Health and Safety Authority, 2011). During the last two years, five fatali¬ties and several accidents have occurred during handling of cattle in Sweden. A method, based on knowledge of the animals’ natural behavior, referred to as low stress stock han¬dling (LSS-method), has been introduced to Sweden for cattle handling (Atkinson, 2011). A handler who consistently uses this method prevents the use of hits, sticks, harsh voice or negative forceful handling techniques. A consistent predictable approach from the han¬dler creates consistent and predictable animal behavior in return. Cattle become more trusting with their handlers and consequently more cooperative. This positive interaction between human being and animal can lead to both a safer work situation and a better animal welfare. On two of five studied farms so far, the LSS-method was actually inter¬vened during the observations, resulted in a successful reversal of conflict behaviour. On farm1, a highly stressed heifer took over three hours in attempt to load into a transport. It was successfully loaded within an hour after the intervention. On another farm, five escaped cows that the farmer had attempted to capture unsuccessfully for three conse¬cutive weeks were successfully captured through using the LSS-method

Scattering properties of weakly bound dimers of fermionic atoms

We consider weakly bound diatomic molecules (dimers) formed in a two-component atomic Fermi gas with a large positive scattering length for the interspecies interaction. We develop a theoretical approach for calculating atom-dimer and dimer-dimer elastic scattering and for analyzing the inelastic collisional relaxation of the molecules into deep bound states. This approach is based on the single-channel zero range approximation, and we find that it is applicable in the vicinity of a wide two-body Feshbach resonance. Our results draw prospects for various interesting manipulations of weakly bound dimers of fermionic atoms.Comment: extended version of cond-mat/030901

Collective oscillations of a trapped Fermi gas near a Feshbach resonance

The frequencies of the collective oscillations of a harmonically trapped Fermi gas interacting with large scattering lengths are calculated at zero temperature using hydrodynamic theory. Different regimes are considered, including the molecular Bose-Einstein condensate and the unitarity limit for collisions. We show that the frequency of the radial compressional mode in an elongated trap exhibits a pronounced non monotonous dependence on the scattering length, reflecting the role of the interactions in the equation of state.Comment: 3 pages, including 1 figur

A cesium gas strongly confined in one dimension : sideband cooling and collisional properties

We study one-dimensional sideband cooling of Cesium atoms strongly confined in a far-detuned optical lattice. The Lamb-Dicke regime is achieved in the lattice direction whereas the transverse confinement is much weaker. The employed sideband cooling method, first studied by Vuletic et al.\cite{Vule98}, uses Raman transitions between Zeeman levels and produces a spin-polarized sample. We present a detailed study of this cooling method and investigate the role of elastic collisions in the system. We accumulate $83(5)$ of the atoms in the vibrational ground state of the strongly confined motion, and elastic collisions cool the transverse motion to a temperature of $2.8 \mu$K=$0.7 \hbar\omega_{\rm osc}/k_{\rm B}$, where $\omega_{\rm osc}$ is the oscillation frequency in the strongly confined direction. The sample then approaches the regime of a quasi-2D cold gas. We analyze the limits of this cooling method and propose a dynamical change of the trapping potential as a mean of cooling the atomic sample to still lower temperatures. Measurements of the rate of thermalization between the weakly and strongly confined degrees of freedom are compatible with the zero energy scattering resonance observed previously in weak 3D traps. For the explored temperature range the measurements agree with recent calculations of quasi-2D collisions\cite{Petr01}. Transparent analytical models reproduce the expected behavior for $k_{\rm B}T \gg \hbar \omega_{\rm osc}$ and also for $k_{\rm B}T \ll \hbar \omega_{\rm osc}$ where the 2D features are prominent.Comment: 18 pages, 12 figure