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

Vector meson-vector meson interaction in a hidden gauge unitary approach

The formalism developed recently to study vector meson--vector meson interaction, and applied to the case of $\rho\rho$, is extended to study the interaction of the nonet of vector mesons among themselves. The interaction leads to poles of the scattering matrix corresponding to bound states or resonances. We show that 11 states (either bound or resonant) get dynamically generated in nine strangeness-isospin-spin channels. Five of them can be identified with those reported in the PDG, i.e., the $f_0(1370)$, $f_0(1710)$, $f_2(1270)$, $f'_2(1525)$, and $K^*_2(1430)$. The masses of the latter three tensor states have been used to fine-tune the free parameters of the unitary approach, i.e., the subtraction constants in evaluating the vector meson -vector meson loop functions in the dimensional regularization scheme. The branching ratios of these five dynamically generated states are found to be consistent with data. The existence of the other six states should be taken as predictions to be tested by future experiments.Comment: typos corrected; more discussions; one of the appendix rearrange

The stability and the shape of the heaviest nuclei

In this paper, we report a systematic study of the heaviest nuclei within the relativistic mean field (RMF) model. By comparing our results with those of the Hartree-Fock-Bogoliubov method (HFB) and the finite range droplet model (FRDM), the stability and the shape of the heaviest nuclei are discussed. The theoretical predictions as well as the existing experimental data indicate that the experimentally synthesized superheavy nuclei are in between the fission stability line, the line connecting the nucleus with maximum binding energy per nucleon in each isotopic chain, and the $\beta$-stability line, the line connecting the nucleus with maximum binding energy per nucleon in each isobaric chain. It is shown that both the fission stability line and the $\beta$-stability line tend to be more proton rich in the superheavy region. Meanwhile, all the three theoretical models predict most synthesized superheavy nuclei to be deformed.Comment: 6 pages, 7 figures, to appear in Journal of Physics

Pairwise wave interactions in ideal polytropic gases

We consider the problem of resolving all pairwise interactions of shock waves, contact waves, and rarefaction waves in 1-dimensional flow of an ideal polytropic gas. Resolving an interaction means here to determine the types of the three outgoing (backward, contact, and forward) waves in the Riemann problem defined by the extreme left and right states of the two incoming waves, together with possible vacuum formation. This problem has been considered by several authors and turns out to be surprisingly involved. For each type of interaction (head-on, involving a contact, or overtaking) the outcome depends on the strengths of the incoming waves. In the case of overtaking waves the type of the reflected wave also depends on the value of the adiabatic constant. Our analysis provides a complete breakdown and gives the exact outcome of each interaction.Comment: 39 page

Clues for the existence of two K1(1270)K_1(1270) resonances

The axial vector meson $K_1(1270)$ was studied within the chiral unitary approach, where it was shown that it has a two-pole structure. We reanalyze the high-statistics WA3 experiment $K^- p\to K^-\pi^+\pi^- p$ at 63 GeV, which established the existence of both $K_1(1270)$ and $K_1(1400)$, and we show that it clearly favors our two-pole interpretation. We also reanalyze the traditional K-matrix interpretation of the WA3 data and find that the good fit of the data obtained there comes from large cancellations of terms of unclear physical interpretation.Comment: published version in PRD; typos corrected; title changed to "Clues for the existence of two $K_1(1270)$ resonances

Two-photon and one photon-one vector meson decay widths of the f0(1370)f_0(1370), f2(1270)f_2(1270), f0(1710)f_0(1710), f2′(1525)f'_2(1525), and K2∗(1430)K^*_2(1430)

We calculate the radiative decay widths, two-photon ($\gamma\gamma$) and one photon-one vector meson ($V\gamma$), of the dynamically generated resonances from vector meson-vector meson interaction in a unitary approach based on the hidden-gauge Lagrangians. In the present paper we consider the following dynamically generated resonances: $f_0(1370)$, $f_0(1710)$, $f_2(1270)$, $f_2'(1525)$, $K^*_2(1430)$, two strangeness=0 and isospin=1 states, and two strangeness=1 and isospin=1/2 states. For the $f_0(1370)$ and $f_2(1270)$ we reproduce the previous results for the two-photon decay widths and further calculate their one photon-one vector decay widths. For the $f_0(1710)$ and $f_2'(1525)$ the calculated two-photon decay widths are found to be consistent with data. The $\rho^0\gamma$, $\omega\gamma$ and $\phi\gamma$ decay widths of the $f_0(1370)$, $f_2(1270)$, $f_0(1710)$, $f'_2(1525)$ are compared with the results predicted by other approaches. The $K^{*+}\gamma$ and $K^{*0}\gamma$ decay rates of the $K^*_2(1430)$ are also calculated and compared with the results obtained in the framework of the covariant oscillator quark model. The results for the two states with strangeness=0, isospin=1 and two states with strangeness=1, isospin=1/2 are predictions that need to be tested by future experiments.Comment: More discussions about the relation between qqbar states and dynamically generated states; version published in PRD

Generalized Jacobi Elliptic One-Monopole - Type A

We present new classical generalized one-monopole solution of the SU(2) Yang-Mills-Higgs theory with the Higgs field in the adjoint representation. We show that this generalized solution with $\theta$-winding number $m=1$ and $\phi$-winding number $n=1$ is an axially symmetric Jacobi elliptic generalization of the 't Hooft-Polyakov one-monopole. We construct this axially symmetric one-monopole solution by generalizing the large distance asymptotic solution of the 't Hooft-Polyakov one-monopole to the Jacobi elliptic functions and solving the second order equations of motion numerically when the Higgs potential is vanishing and non vanishing. These solutions are regular non-BPS finite energy solutions.Comment: 17 pages, 5 figure

Free energy conservation in ab initio molecular dynamics simulations and homogeneous melt nucleation

The Z method is a popular atomistic simulation method for determining the melting temperature of solids by using a sequence of molecular dynamics(MD) runs in the microcanonical(NVE) ensemble to target the lowest system energy where the solid always melts. Homogeneous melting at the superheating critical limit($T_h$), is accompanied by a temperature drop to the equilibrium melting temperature($T_m$). Implementation of the Z method interfaced with modern {\it ab initio} electronic structure packages use Hellman-Faynman dynamics to propagate the ions in the NVE ensemble with the Mermin free energy plus the ionic kinetic energy conserved. So the electronic temperature($T_{el}$) is kept fixed along the trajectory which may introduce some spurious ion-electron interactions in MD runs with large temperature changes. We estimate possible systematic errors in evaluating melting temperature with different choices of $T_{el}$. MD runs with the $T_{el}$ = $T_h$ and $T_{el}$ = $T_m$ shows that the difference in melting temperature can be 200-300 K (3-5\% of the melting temperature) for our two test systems. Our results are in good agreement with previous studies with different methods, suggesting the CaSiO$_3$ and SiO$_2$ melts at around 6500 at 100 GPa and 6000 K at 160 GPa. The melting temperature decreases with increasing $T_{el}$ due to the increasing entropic stabilisation of the liquid and the system melts about 3 times faster with $T_{el} = T_h$ than with $T_{el} = T_m$. A careful choice of $T_{el}$ in BOMD is essential for the critical evaluation of the Z method especially at very high temperatures. Inspection of the homogeneous melting process shows that melting occurs via a two-step mechanism: 1) melting of the anion sublattice is accompanied by a small drop in temperature and 2) the formation of small defects which trigger the formation of small liquid clusters and fully melted.Comment: 10 figures, 17 page

Ab initio constraints on silica melting to 500 GPa

The melting curve of pure silica (SiO$_2$) was determined using {\it ab initio} density functional theory together with the solid-liquid coexisting approach, thermodynamic integration and the Z method. The melting curves are consistent with a smooth slow increase in a large region from 50 GPa (dT/dP $\approx$ 15 K/GPa) to about 500 GPa (dT/dP $\approx$ 5 K/GPa) without any abrupt changes at around 120 GPa and 300 GPa as seen in some recent experimental and computational studies. The topography of the melting curve above 50 GPa is consistent with a gradual change in the distribution of the Si coordination numbers in the liquid state and the absence of large changes in the density following solid-solid phase transitions. The pair distribution functions show that the structural correlation in the liquid is mainly short-ranged and that the Si-O bond is stiff. The densification of the melt structure with pressure above 50 GPa is therefore due to an increase in 7- and 8-fold coordinated silicon