The effect of experience of ramps at rear on the subsequent ability of layer pullets to negotiate a ramp transition

In commercial situations, laying hens must negotiate levels to reach resources such as food, water and litter. Providing ramps in aviary systems reduces collisions and resultant keel bone fractures in adults. We investigated whether providing ramps during rear improved the ability of birds to transition between levels. Chicks were reared commercially in two flocks both of which provided access to raised structures from three weeks of age. One flock had no ramps, but the other flock was provided with additional access to two types of ramp (wooden ladders, and grids formed from commercial poultry slats placed at an angle). At 8 weeks of age, 64 birds (32 from each rearing condition) were transferred to an experimental facility. At 10 weeks of age, 32 pullets from each group were trained to run to a food reward. During testing at 12–14 weeks of age the pullets accessed the food reward by moving up or down a ramp. The pullets’ behaviours and time taken to complete the task were recorded. Ramp use over three days was also observed in a room replicating a small-scale single-tier system. Four groups of 16 birds aged 12–14 weeks were housed for three days and the number of transitions between the raised tier and litter were recorded. For upward transitions, more ramp-reared birds than control birds succeeded in reaching the food reward for both ladder (52% vs 13%) and grid ramps (74% vs 42%). Birds from the ramp-reared group took significantly less time to complete an upwards transition (68.8s ± 49.3) than the control group (100s ± 37.6) (p = 0.001). In addition, the control group showed more behaviours indicative of hesitancy (moving away, head orientations, ground pecking and crouching) before transitioning, and signs of difficulty when making upward transitions (crouched walks, pauses, turning, returning and escape attempts). In the group housing observations, the ramp reared groups had almost double the number of transitions between the slats and litter on day one compared to the control group. This difference was reduced by day three. In summary, this suggests there are positive effects of providing ramp experience during rear shown by any combination of bird mobility, strength or cognitive ability leading to an increase in apparent confidence in older pullets. It is not known whether these benefits persist through to the laying period, but no detrimental effects were noted so we suggest that ramps should be included from the early rearing period onwards

The dissipative linear Boltzmann equation for hard spheres

We prove the existence and uniqueness of an equilibrium state with unit mass to the dissipative linear Boltzmann equation with hard--spheres collision kernel describing inelastic interactions of a gas particles with a fixed background. The equilibrium state is a universal Maxwellian distribution function with the same velocity as field particles and with a non--zero temperature lower than the background one, which depends on the details of the binary collision. Thanks to the H--theorem we then prove strong convergence of the solution to the Boltzmann equation towards the equilibrium.Comment: 17 pages, submitted to Journal of Statistical Physic

Acta Societatis pro fauna et flora Fennica

Kielet saksa ja ruotsi

Mass measurements in the vicinity of the doubly-magic waiting point 56Ni

Masses of 56,57Fe, 53Co^m, 53,56Co, 55,56,57Ni, 57,58Cu, and 59,60Zn have been determined with the JYFLTRAP Penning trap mass spectrometer at IGISOL with a precision of dm/m \le 3 x 10^{-8}. The QEC values for 53Co, 55Ni, 56Ni, 57Cu, 58Cu, and 59Zn have been measured directly with a typical precision of better than 0.7 keV and Coulomb displacement energies have been determined. The Q values for proton captures on 55Co, 56Ni, 58Cu, and 59Cu have been measured directly. The precision of the proton-capture Q value for 56Ni(p,gamma)57Cu, Q(p,gamma) = 689.69(51) keV, crucial for astrophysical rp-process calculations, has been improved by a factor of 37. The excitation energy of the proton emitting spin-gap isomer 53Co^m has been measured precisely, Ex = 3174.3(10) keV, and a Coulomb energy difference of 133.9(10) keV for the 19/2- state has been obtained. Except for 53Co, the mass values have been adjusted within a network of 17 frequency ratio measurements between 13 nuclides which allowed also a determination of the reference masses 55Co, 58Ni, and 59Cu.Comment: 14 pages, 13 figures, submitted to Phys. Rev.

Charged particle jet measurements with the ALICE experiment in proton-proton collisions at the LHC

We present preliminary results of measurements of charged particle jet properties in proton-proton collisions at $\sqrt{s}$ = 7 TeV using the ALICE detector. Jets are reconstructed using $\rm anti-k_{T}, k_{T}$ and SISCone jet finding algorithms with resolution parameter $R=0.4$ in the range of transverse momentum from 20 to 100 GeV/$c$ in the midrapidity region (\mid\eta\mid\textless 0.5). The uncorrected charged jet spectra obtained using the three different jet finders show good agreement. The data are compared to predictions from PYTHIA-Perugia0, PYTHIA-Perugia2011, and PHOJET. The mean charged particle multiplicity in leading jets increases with increasing jet $p_{\rm T}$ and is consistent with model predictions. The radial distributions of transverse momentum about the jet direction and the distributions of the average radius containing 80% of the total jet $p_{\rm T}$ found in the jet cone ($R = 0.4$ in this analysis), indicate that high $p_{\rm T}$ jets are more collimated than low $p_{\rm T}$ jets.Comment: 6 pages, 6 figures, Conference Proceedings submitted for the 28th Winter Workshop on Nuclear Dynamics, Puerto Rico, April 7-14, 201