A note on reaction to novel stimulus and restraint by therapeutic riding horses

Little research has been done to measure reactivity objectively in therapeutic riding horses (TRH). As individual reactivity and chronic stress could be assessed by exposing animals to acute, novel stressors, the authors of this work aimed at comparing reactions of TRHs and jumping horses (JH) to two challenges. Four TRHs and four JHs were exposed to a restraint covering their head with a hood for I h and to a startling stimulus (a 40 cm long, red and white synthetic holiday garland shaken with a rustling noise inside the box). Heart rate (HR) and heart rate variability (HRV) were recorded continuously and telemetrically, the reaction was video-recorded and analysed with a software for behavioural analysis. Blood samples were collected before and after each challenge to determine lymphocyte proliferation and other biochemical parameters. Horses spent most of the time immobile, during the challenges (p < 0.05). TRHs had a significantly higher average basal HR than JH (p < 0.05), probably due to their better condition. HR varied among different behaviours during the restraint (p < 0.05): the average HR during "pawing" was higher than during other behaviours (p < 0.005). A significant decrease in the proliferation of lymphocytes in samples taken after the removal of the hood (p < 0.05) was found, while the other stress related parameters did not vary significantly after the challenges. The authors conclude that TRHs did not react less than JHs to the new stimuli and this should be taken into consideration while planning their daily work and management

Electron-magnon coupling and nonlinear tunneling transport in magnetic nanoparticles

We present a theory of single-electron tunneling transport through a ferromagnetic nanoparticle in which particle-hole excitations are coupled to spin collective modes. The model employed to describe the interaction between quasiparticles and collective excitations captures the salient features of a recent microscopic study. Our analysis of nonlinear quantum transport in the regime of weak coupling to the external electrodes is based on a rate-equation formalism for the nonequilibrium occupation probability of the nanoparticle many-body states. For strong electron-boson coupling, we find that the tunneling conductance as a function of bias voltage is characterized by a large and dense set of resonances. Their magnetic field dependence in the large-field regime is linear, with slopes of the same sign. Both features are in agreement with recent tunneling experiments.Comment: 4 pages, 2 figure

Distribution of level curvatures for the Anderson model at the localization-delocalization transition

We compute the distribution function of single-level curvatures, $P(k)$, for a tight binding model with site disorder, on a cubic lattice. In metals $P(k)$ is very close to the predictions of the random-matrix theory (RMT). In insulators $P(k)$ has a logarithmically-normal form. At the Anderson localization-delocalization transition $P(k)$ fits very well the proposed novel distribution $P(k)\propto (1+k^{\mu})^{3/\mu}$ with $\mu \approx 1.58$, which approaches the RMT result for large $k$ and is non-analytical at small $k$. We ascribe such a non-analiticity to the spatial multifractality of the critical wave functions.Comment: 4 ReVTeX pages and 4(.epsi)figures included in one uuencoded packag

A pilot study on yearlings' reactions to handling in relation to the training method

Handling and training methods of horses, which specially emphasize the importance of understanding horse body language and the use of reinforcements, are often used in practice, yet their effects are not completely known. This study investigated whether the use of a sympathetic approach during the preparation for public auctions influenced the reactivity of young horses towards humans. Sixteen thoroughbred yearlings were prepared for the public auctions during one month: eight horses ("Control") were handled according to conventional practices, while the others ("Treated") were handled with two sessions of basic training based on body language. The reactivity of horses was assessed in the presence of an "unfamiliar person" and a "familiar person" inside the horse's box. The experimenter recorded the presence/absence of selected behaviors during seven observational moments: "approaching the box," "opening the box door," "entering the box," and four consecutive observations every thirty seconds. Reactivity of horses was ranked during the first experience of "bit," "grooming," "shower," and application of the "surcingle." Heart rate was telemetrically recorded during this final test. At the end of the auction preparation, "Treated" horses exhibited more "contact" (p = 0.08) and "lick" (p < 0.05) behaviors in the presence of a person. "Control" horses showed higher (non-significant) percentages of negative (more nervous) rankings during "bit," "grooming," and "surcingle" tests. Two "Control" horses showed aggressive behavior during the application of the surcingle and the test was interrupted to guarantee person and animal safety. In this pilot study, horses handled with a sympathetic approach showed less reactive behaviors compared with "Control" horses. It would be interesting to enlarge the sample size and assess if the use of non-coercive handling during the whole training period influences their welfare positively and for a long time

New Class of Random Matrix Ensembles with Multifractal Eigenvectors

Three recently suggested random matrix ensembles (RME) are linked together by an exact mapping and plausible conjections. Since it is known that in one of these ensembles the eigenvector statistics is multifractal, we argue that all three ensembles belong to a new class of critical RME with multifractal eigenfunction statistics and a universal critical spectral statitics. The generic form of the two-level correlation function for weak and extremely strong multifractality is suggested. Applications to the spectral statistics at the Anderson transition and for certain systems on the border of chaos and integrability is discussed.Comment: 4 pages RevTeX, resubmitte

Spectral properties of a generalized chGUE

We consider a generalized chiral Gaussian Unitary Ensemble (chGUE) based on a weak confining potential. We study the spectral correlations close to the origin in the thermodynamic limit. We show that for eigenvalues separated up to the mean level spacing the spectral correlations coincide with those of chGUE. Beyond this point, the spectrum is described by an oscillating number variance centered around a constant value. We argue that the origin of such a rigid spectrum is due to the breakdown of the translational invariance of the spectral kernel in the bulk of the spectrum. Finally, we compare our results with the ones obtained from a critical chGUE recently reported in the literature. We conclude that our generalized chGUE does not belong to the same class of universality as the above mentioned model.Comment: 12 pages, 3 figure

Avoidance distance test in goats: a comparison with its application in cows

The present study investigates the feasibility in goats of an avoidance distance (AD) behaviour test set-up for cattle, and compares the results in the two species to assess the suitability of the test for on-farm welfare evaluation in goat farms. The tests were performed on 324 lactating cows (170 in small farms and 154 in large farms) and 271 lactating goats (108 in small farms and 163 in large farms), housed in free stall farms (12 dairy cattle and 17 dairy goat farms) in the Province of Sondrio, Northern Italy, following a protocol validated for dairy cows in the Welfare Quality\uae project. After the assessors were adequately trained, this test was relatively easy to perform and no major difficulties were faced in either species. Goats exhibited a higher level of confidence with humans, as showed by lower AD (goats: 68.60 \ub1 4.98 cm; cows: 71.36 \ub1 4.37 cm; p < 0.10) and higher frequency of contacts (AD = 0) (goats: 45.8%; cows: 31.2%; p < 0.001). Farm size significantly affected AD values (lower in small farms) and frequency of contacts (higher in small farms) in goats, but not in cows. This was probably due to the less marked management difference between large and small farms of cattle than those of goats. The AD test seems feasible in goats; however, the experimenter contacted nearly half of the goats. To improve the sensitivity, a further level - represented by the possibility of gently stroking the goat's head after the contact - may be included in the test in addition to contact

Welfare issues of horses : an overview and practical recommendations

The largest proportion of the world's horses are still used for work in agriculture and traction, however in the western countries they are increasingly kept for recreational and social purposes, breeding, sport and competition. It is often assumed that horses enjoys better farming conditions than other species, yet they have specific needs which should be fulfilled in order to have a proper welfare. This paper will review the main welfare issues of horses and the following aspects will be considered: nutrition, housing and management, clinical problems, behaviour problems, training and riding, transportation, measuring welfare. Horses are social animals that live in groups in close contact with conspecifics. They spend most of their waking hours moving at walk, grazing and eating grass. Some of the constraints imposed on horses during the last centuries conflict to their naturally evolved behaviour. Effective and humane handling of horses positively affects many important aspects like the safety of man, the performance level and the welfare of horses. It is an essential condition for keeping horses that handlers, riders, trainers, farriers and veterinarians have proper knowledge of the behaviour of the horse in order to fulfil their natural needs and guarantee their welfare

Instability of antiferromagnetic magnons in strong fields

We predict that spin-waves in an ordered quantum antiferromagnet (AFM) in a strong magnetic field become unstable with respect to spontaneous two-magnon decays. At zero temperature, the instability occurs between the threshold field $H^*$ and the saturation field $H_c$. As an example, we investigate the high-field dynamics of a Heisenberg antiferromagnet on a square lattice and show that the single-magnon branch of the spectrum disappears in the most part of the Brillouin zone.Comment: RevTeX, 4 pages, 3 figures, accepted to PR