A novel method for the injection and manipulation of magnetic charge states in nanostructures

Realising the promise of next-generation magnetic nanotechnologies is contingent on the development of novel methods for controlling magnetic states at the nanoscale. There is currently demand for simple and flexible techniques to access exotic magnetisation states without convoluted fabrication and application processes. 360 degree domain walls (metastable twists in magnetisation separating two domains with parallel magnetisation) are one such state, which is currently of great interest in data storage and magnonics. Here, we demonstrate a straightforward and powerful process whereby a moving magnetic charge, provided experimentally by a magnetic force microscope tip, can write and manipulate magnetic charge states in ferromagnetic nanowires. The method is applicable to a wide range of nanowire architectures with considerable benefits over existing techniques. We confirm the method's efficacy via the injection and spatial manipulation of 360 degree domain walls in Py and Co nanowires. Experimental results are supported by micromagnetic simulations of the tip-nanowire interaction.Comment: in Scientific Reports (2016

Lop-eared rabbits have more aural and dental problems than erect-eared rabbits: a rescue population study

This research aimed to assess whether rabbits having lop ears, an artificially selected conformation, compromises welfare. We investigated the occurrence of aural and dental pathology in lop-eared compared with erect-eared rabbits. Thirty rabbits (15 lop-eared and 15 erect-eared) from a rabbit-only rescue shelter were examined. An otoscope was used to visualise the ear canals and mouth. Samples were taken from each ear to examine for mites, bacteria and yeast. Medical records were also examined. Lop-eared rabbits showed statistically significantly more frequent ear canal stenosis, higher scores of cerumen and erythema and more frequent potential pain response during ear examination, compared with erect-eared rabbits. We also found statistically significantly more frequent incisor pathology, molar overgrowth, molar sharpness, molar spurs and history of veterinary dental treatment in lop-eared compared with erect-eared rabbits. The effect sizes were often large. Age was not statistically significant between the lop-eared and erect-eared rabbit groups. Thus, lop-eared rabbits were at an increased risk of aural and dental pathology in this study. This brings into debate the ethics of breeding and buying lop-eared rabbits, as they are more likely to suffer conditions that negatively impact welfare, such as pain, and potentially deafness and difficulty eating

Olfactory variation in mouse husbandry and its implications for refinement and standardisation: UK survey of non-animal scents

With their highly sensitive olfactory system, the behaviour and physiology of mice are not only influenced by the scents of conspecifics and other species, but also by many other chemicals in the environment. The constraints of laboratory housing limit a mouse’s capacity to avoid aversive odours that could be present in the environment. Potentially odorous items routinely used for husbandry procedures, such as sanitizing products and gloves, could be perceived by mice as aversive or attractive, and affect their behaviour, physiology and experimental results. A survey was sent to research institutions in the UK to enquire about husbandry practices that could impact on the olfactory environment of the mouse. Responses were obtained from 80 individuals working in 51 institutions. Husbandry practices varied considerably. Seventy percent of respondents reported always wearing gloves for handling mice, with nitrile being the most common glove material (94%) followed by latex (23%) and vinyl (14%). Over six different products were listed for cleaning surfaces, floors, anaesthesia and euthanasia chambers and behavioural apparatus. In all cases Trigene™ (now called Anistel™) was the most common cleaning product used (43, 41, 40 and 49%, respectively). Depending on the attribute considered, between 7 and 19% of respondents thought that cleaning products definitely, or were likely to, have strong effects on standardization, mouse health, physiology or behaviour. Understanding whether and how these odours affect mouse welfare will help to refine mouse husbandry and experimental procedures through practical recommendations, to improve the quality of life of laboratory animals and the experimental data obtained

Concurrent 43 and 86 GHz Very Long Baseline Polarimetry of 3C273

We present sub-milliarcsecond resolution total intensity and linear polarization VLBI images of 3C273, using concurrent 43 and 86 GHz data taken with the Very Long Baseline Array in May 2002. The structure seen in the innermost jet suggest that we have fortuitously caught the jet in the act of changing direction. The polarization images confirm that the core is unpolarized (fractional polarization m < 1 %) at 86 GHz, but also show well ordered magnetic fields (m ~ 15 %) in the inner jet, at a projected distance of 2.3 pc from the core. In this strongly polarized region, the rotation measure changes across the jet by 4.2 x 10^{4} rad m^{-2} over an angular width of about 0.3 milliarcseconds. If the lack of polarization in the core is also attributed to a Faraday screen, then a rotation measure dispersion > 5.2 x 10^{4} rad m^{-2} must be present in or in front of that region. These are among the highest rotation measures reported so far in the nucleus of any active galaxy or quasar, and must occur outside (but probably close to) the radio emitting region. The transverse rotation measure gradient is in the same sense as that observed by Asada et al and by Zavala and Taylor at greater core distances. The magnitude of the transverse gradient decreases rapidly with distance down the jet, and appears to be variable.Comment: 4 pages, LaTeX, 3 postscript figures, submitted to Astrophysical Journal Letter

A Vicious Cycle: A Cross-Sectional Study of Canine Tail-Chasing and Human Responses to It, Using a Free Video-Sharing Website

Tail-chasing is widely celebrated as normal canine behaviour in cultural references. However, all previous scientific studies of tail-chasing or ‘spinning’ have comprised small clinical populations of dogs with neurological, compulsive or other pathological conditions; most were ultimately euthanased. Thus, there is great disparity between scientific and public information on tail-chasing. I gathered data on the first large (n = 400), non-clinical tail-chasing population, made possible through a vast, free, online video repository, YouTube™. The demographics of this online population are described and discussed. Approximately one third of tail-chasing dogs showed clinical signs, including habitual (daily or ‘all the time’) or perseverative (difficult to distract) performance of the behaviour. These signs were observed across diverse breeds. Clinical signs appeared virtually unrecognised by the video owners and commenting viewers; laughter was recorded in 55% of videos, encouragement in 43%, and the commonest viewer descriptors were that the behaviour was ‘funny’ (46%) or ‘cute’ (42%). Habitual tail-chasers had 6.5+/−2.3 times the odds of being described as ‘Stupid’ than other dogs, and perseverative dogs were 6.8+/−2.1 times more frequently described as ‘Funny’ than distractible ones were. Compared with breed- and age-matched control videos, tail-chasing videos were significantly more often indoors and with a computer/television screen switched on. These findings highlight that tail-chasing is sometimes pathological, but can remain untreated, or even be encouraged, because of an assumption that it is ‘normal’ dog behaviour. The enormous viewing figures that YouTube™ attracts (mean+/−s.e. = 863+/−197 viewings per tail-chasing video) suggest that this perception will be further reinforced, without effective intervention

Visitor effects on zoo-housed Sulawesi crested macaque (Macaca nigra) behaviour: Can signs with ‘watching eyes’ requesting quietness help?

Visiting public can cause changes in the behaviour of zoo-housed primates. These effects, if indicative of stress, can be of welfare concern. However, few options to mitigate visitor effects through modulating visitor behaviour have been explored. Here we evaluated the effects of visitor number and visitor noise level on the behaviour of five UK groups of Sulawesi crested macaques. We also investigated whether visitor behaviour can be effectively modulated through targeted signage requesting visitors to be quiet, and assessed the use of signs incorporating salient ‘watching’ human eyes, novel to a zoo setting, alongside ‘control’ signs lacking eyes. We used scan sampling to collect over 100 h of behavioural observation data, analysis of which indicated that Sulawesi crested macaques were significantly affected by both visitor number and noise level at all five zoos. We found that active behaviours, such as locomotion or foraging, and behaviours identified as negative for welfare, such as vigilance, increased with increasing visitor number and noise levels, whereas resting and social huddling decreased. The extent to which these behavioural changes reflect welfare, particularly the increase seen in active behaviours, is not clear. We also found that both sign treatments, with and without salient eyes, slightly but significantly reduced visitor noise levels compared with no sign, although signs displaying human eyes were not more effective than the control signs. Our results highlight a need for further research into active behaviours to assess whether increases in these behaviours are associated with stress. While we found signage to be a promising tool to mitigate against these visitor effects, our results also suggest areas in which signs incorporating salient human eyes could be adapted for the zoo environment in order to realise their full potential