1,200 research outputs found
Robustness of the transition against compositional and structural ageing in S/F/S heterostructures
We have studied the temperature induced thermodynamic transition in
Nb/PdNi/Nb Superconductor/Ferromagnetic/Superconductor (SFS) heterostructures
by microwave measurements of the superfluid density. We have observed a shift
in the transition temperature with the ageing of the heterostructures,
suggesting that structural and/or chemical changes took place. Motivated by the
electrodynamics findings, we have extensively studied the local structural
properties of the samples by means of X-ray Absorption Spectroscopy (XAS)
technique, and the compositional profile by Time-of-Flight Secondary Ion Mass
Spectrometry (ToF-SIMS). We found that the samples have indeed changed their
properties, in particular for what concerns the interfaces and the composition
of the ferromagnetic alloy layer. The structural and compositional data are
consistent with the shift of the transition toward the behaviour of
heterostructures with different F layers. An important emerging indication to
the physics of SFS is the weak relevance of the ideality of the interfaces:
even in aged samples, with less-than-ideal interfaces, the temperature-induced
transition is still detectable albeit at a different critical F
thickness.Comment: 11 pages, 9 figures, accepted for publication on Phys. Rev. B,
http://journals.aps.org/prb
Effects of an inactivated vaccine for bovine mycoplasmosis on calves naturally affected with Mycoplasma bovis
Three autogenous vaccine trials were carried out on farms where Mycoplasma bovis had been identified as a major pathogen. The first trial was carried on a veal farm in the Lombardia region of northern Italy. Vaccine, prepared by saponising an M bovis strain taken from the farm some months before, was given as single inoculation to 24 calves on arrival while 19 were left unvaccinated. Six months later calves were sent to the abattoir where lungs were examined for gross pathological lesions. The mean weight of the vaccinated group was higher though not significantly so and mean lesion scores were similar; however the percentage of vaccinated calves with severe lung lesions and pleuritis was lower than in the non vaccinates. A second trial was carried out in northern England on a farm where monthly batches of male calves from a nearby dairy herd were reared under a feedlot system. One group of 27 calves were vaccinated with a saponised strain of M bovis isolated from the lungs of a pneumonic calf on the farm prior to the start of the trial. A second batch of 25 calves was left unvaccinated. The groups of calves were monitored for nine months prior to slaughter and records kept of antibiotic usage and mortality. The mortality rates in the vaccinated calves were about 15% compared to 28% in unvaccinated calves; however there was no difference in the number of times calves were treated for respiratory disease. A third batch of calves, treated with oxytetracycline on arrival because a number were already showing respiratory signs, had a lower mortality rate and fewer subsequent treatments. A third trial was carried out on a milk veal unit in the Veneto region of Italy. A group of 19 calves were vaccinated on arrival with a saponised isolate taken earlier from the farm; a similar number of calves of the same batch were left unvaccinated. After 6 months animals were routinely processed at the abattoir and lungs inspected. Results showed that vaccinated calves had higher mean body weights and although similar mean lung scores there was a smaller percentage of vaccinated calves with severe lung lesions and pleuritis
Plasma disposition, concentration in the hair, and anthelmintic efficacy of eprinomectin after topical administration in donkeys
Objective-To investigate plasma disposition, concentration in the hair, and anthelmintic efficacy of eprinomectin after topical administration in donkeys. Animals-12 donkeys naturally infected with strongyle nematodes. Procedures-The pour-on formulation of eprinomectin approved for use in cattle was administered topically to donkeys at a dosage of 0.5 mg/kg. Heparinized blood samples and hair samples were collected at various times between 1 hour and 40 days after administration. Samples were analyzed via high-performance liquid chromatography with fluorescence detection. Fecal strongyle egg counts were performed by use of a modified McMaster technique before and at weekly intervals for 8 weeks after treatment. Results-Plasma concentration and systemic availability of eprinomectin were relatively higher in donkeys, compared with values reported for other animal species. Concerning the anthelmintic efficacy against strongyle nematodes, eprinomectin was completely effective (100%) on days 7 and 14 and highly effective (> 99%) until the end of the study at 56 days after treatment. No abnormal clinical signs or adverse reactions were observed for any donkeys after treatment. Conclusions and Clinical Relevance-Eprinomectin had excellent safety. The relatively high plasma concentration after topical administration could result in use of eprinomectin for the control and treatment of parasitic diseases in donkeys
Growth performance in heavy lambs experimentally treated with 17 β-estradiol
European and Italian legislation have banned use
of growth promoters in livestock since 1988, but epidemiological
data show that anabolic drugs are still being used
illegally. Recent surveys carried out on the cattle farms in
Northern Italy have confirmed the presence of growthpromoting
hormones. Authors report data on growth performances
in 80 Valle del Belice×Comisana weaned lambs
experimentally treated with 17 beta-estradiol with 0.5 ml
solution of oil Depot Estradiol ® (containing 5 mg of 17β-
estradiol valerate) by intramuscular injection into the thigh.
The experiment was founded by the National Ministry of
Health, to validate histological test for surveillance and
control of growth-promoting hormones in sheep. This study
confirmed the strong correlation between clinical and anatomopathological
features and growth performances of treated
animals. Otherwise, no significant differences were found on in vivo performance of the lambs. Estradiol treatment
showed heavier shoulders and necks on treated lambs,
while the loins were significantly lighter. Moreover, lambestradiol-
treated groups showed lower separable and inseparable
fat percentage than lamb-control groups
Total Degree Formula for the Generic Offset to a Parametric Surface
We provide a resultant-based formula for the total degree w.r.t. the spatial
variables of the generic offset to a parametric surface. The parametrization of
the surface is not assumed to be proper.Comment: Preprint of an article to be published at the International Journal
of Algebra and Computation, World Scientific Publishing,
DOI:10.1142/S021819671100680
A family of virtual contraction based controllers for tracking of flexible-joints port-Hamiltonian robots:Theory and experiments
In this work, we present a constructive method to design a family of virtual contraction based controllers that solve the standard trajectory tracking problem of flexible-joint robots in the port-Hamiltonian framework. The proposed design method, called virtual contraction based control, combines the concepts of virtual control systems and contraction analysis. It is shown that under potential energy matching conditions, the closed-loop virtual system is contractive and exponential convergence to a predefined trajectory is guaranteed. Moreover, the closed-loop virtual system exhibits properties such as structure preservation, differential passivity, and the existence of (incrementally) passive maps. The method is later applied to a planar RR robot, and two nonlinear tracking control schemes in the developed controllers family are designed using different contraction analysis approaches. Experiments confirm the theoretical results for each controller
Efficacy of eprinomectin pour-on against Dictyocaulus arnfieldi infection in donkeys (Equus asinus).
A trial to assess the efficacy of eprinomectin (EPM) against the lungworm Dictyocaulus arnfieldi was carried out on 15, naturally-infected donkeys. Ten animals were treated with a 'pour-on' EPM preparation (at a dose of 0.5mg/kg bodyweight), and five animals acted as controls. EPM was 100% effective in eliminating faecal larvae from day 7, until the end of study at day 28. No adverse drug-reactions or side-effects were observed in any of the treated donkeys
- …