Our current research effort is directed towards fabricating PZT thick-films on a supporting substrate for use within industrial process monitoring equipment. The use of thick films in this application confers a number of important benefits. These include more straightforward device fabrication and the ability to fabricate transducers in more complex non-rectangular geometries. However, an important drawback of our current techniques is the low thickness (25-40¿m) of the deposited PZT film. The centre frequency of such a layer when used as a transducer is expected to be greater than 10MHz. Such high frequencies often make such transducers impractical for conventional B-scan imaging since overall beam penetration depth is severely curtailed. Ideally, to make such devices more practical a technique is required that allows the device centre frequency to be reduced without changing the thickness of the active PZT layer. In this paper we describe one such technique that uses multiple impedance matched ¿/2 backing layers to achieve the frequency reduction required.
Lethal spring traps are widely used for killing small mammals in the UK. Many require government approval, based primarily on humaneness. However, mole traps and break-back traps for rats and mice are exempt; those available vary widely in price and apparent quality. The EU is considering implementing a Trapping Directive that would alter UK legislation, and a recent report advised the EU that trapping legislation should cover all trapped species and encourage improvement of traps. Mechanical trap performance is often used as an indicator of welfare impact. We examined the mechanical evidence for scope to improve the welfare standards of rat, mouse and mole spring traps. We measured mechanical performance among a range of rat, mouse and mole traps. Impact momentum values varied 6-8 fold, and clamping force values 4-5.5 fold, among traps for killing each species. There was considerable overlap in the performance of rat and mouse traps. Trap-opening angle and spring type were related to impact momentum and clamping force in traps for both species. There was no relationship between price and mechanical performance in traps for any species, except talpa mole traps. We are unable to judge the direct welfare impact of the traps tested, but rather the potential welfare threat associated with their exemption from approval. The wide variation in mechanical performance in traps for each species, overlap in performance between rat and mouse traps and increasing availability of weaker plastic rodent traps indicate considerable scope for improving the humaneness of spring traps for rats, mice and moles. We conclude that all such traps should be subject to the UK approval process. New welfare categories might improve trap standards further. Our results could also help improve rodent trap design and assist consumers in selecting more powerful traps. Many thousands of rats, mice and moles might benefit.
Currently, there is no existing method for automatically tracking the location of burrowing animals when they are underground, consequently zoologists only have a partial view of their subterranean behaviour and habits. Conventional RF based methods of localization are unsuitable because electromagnetic waves are severely attenuated by soil and moisture. Here, we use an as yet unexploited method of localization, namely magneto-inductive (MI) localization. Magnetic fields are not affected by soil or water, and thus have virtually unattenuated ground penetration. In this paper, we present a method that allows the position of an animal to be determined through soil. Not only does this enable the study of behaviour, it also allows the structure of the tunnel to be automatically mapped as the animal moves through it. We describe the application for tracking wild European Badgers (Meles meles) within their burrows, providing experimental data from a two month deployment.
We establish intra-individual and inter-annual variability in European badger (Meles meles) autumnal nightly activity in relation to fine-scale climatic variables, using tri-axial accelerometry. This contributes further to understanding of causality in the established interaction between weather conditions and population dynamics in this species. Modelling found that measures of daylight, rain/humidity, and soil temperature were the most supported predictors of ACTIVITY, in both years studied. In 2010, the drier year, the most supported model included the SOLAR*RH interaction, RAIN, and 30cmTEMP (w = 0.557), while in 2012, a wetter year, the most supported model included the SOLAR*RH interaction, and the RAIN*10cmTEMP (w = 0.999). ACTIVITY also differed significantly between individuals. In the 2012 autumn study period, badgers with the longest per noctem activity subsequently exhibited higher Body Condition Indices (BCI) when recaptured. In contrast, under drier 2010 conditions, badgers in good BCI engaged in less per noctem activity, while badgers with poor BCI were the most active. When compared on the same calendar dates, to control for night length, duration of mean badger nightly activity was longer (9.5 hrs ±3.3 SE) in 2010 than in 2012 (8.3 hrs ±1.9 SE). In the wetter year, increasing nightly activity was associated with net-positive energetic gains (from BCI), likely due to better foraging conditions. In a drier year, with greater potential for net-negative energy returns, individual nutritional state proved crucial in modifying activity regimes; thus we emphasise how a 'one size fits all' approach should not be applied to ecological responses.
The increasing adoption of wireless sensor network technology in a variety of applications, from agricultural to volcanic monitoring, has demonstrated their ability to gather data with unprecedented sensing capabilities and deliver it to a remote user. However, a key issue remains how to maintain these sensor network deployments over increasingly prolonged deployments. In this article, we present the challenges that were faced in maintaining continual operation of an automated wildlife monitoring system over a one-year period. This system analyzed the social colocation patterns of European badgers ( Meles meles ) residing in a dense woodland environment using a hybrid RFID-WSN approach. We describe the stages of the evolutionary development, from implementation, deployment, and testing, to various iterations of software optimization, followed by hardware enhancements, which in turn triggered the need for further software optimization. We highlight the main lessons learned: the need to factor in the maintenance costs while designing the system; to consider carefully software and hardware interactions; the importance of rapid prototyping for initial deployment (this was key to our success); and the need for continuous interaction with domain scientists which allows for unexpected optimizations.
Objective To assess the use of Global Positioning System receiver (GPS) derived performance measures for differentiating between: 1) different outdoor activities in healthy dogs; 2) healthy dogs and those with osteoarthritis; 3) osteoarthritic dogs before and after treatment with non-steroidal anti-inflammatory analgesia. Design Prospective study. Animals Ten healthy dogs and seven dogs with osteoarthritis of the elbow joint (OA dogs). Procedure Healthy dogs were walked on a standard route on-lead, off-lead and subjected to playing activity (chasing a ball) whilst wearing a GPS collar. Each dog was walked for five consecutive days. Dogs with OA were subjected to a single off-lead walk whilst wearing a GPS collar, and then administered oral Carprofen analgesia daily for two weeks. OA dogs were then subjected to the same walk, again wearing a GPS collar. Results GPS derived measures of physical performance could differentiate between on-lead activity, off-lead activity and playing activity in healthy dogs, and between healthy dogs and OA dogs. Variation in the performance measures analysed was greater between individual dogs than for individual dogs on different days. Performance measures could differentiate healthy dogs from OA dogs. OA Dogs treated with Carprofen analgesia showed improvements in their physical performance, which returned to values indistinguishable from those of healthy dogs on nearly all the measures assessed. Conclusions and Clinical Relevance GPS derived measures of physical performance in dogs are objective, easy to quantify, and can be used to gauge the effects of disease and success of clinical treatments. Specific stimuli can be used to modulate physical performance beyond the self-governed boundaries that dogs will naturally express when allowed to exercise freely without stimulation.
Summary Despite the importance of the subterranean ecotope, knowledge of underground movement and behaviour has been extremely limited. Previous technologies have relied upon techniques with very low spatial or temporal resolution, such as VHF telemetry. Rather incongruously, therefore, relatively simple underground activity regimes have often been assumed, with insufficient attention to the ecological importance of burrow use. We test the capability of Magneto‐Inductive ( MI ) tracking, recording underground movement within a European badger sett over a 2 week period in February. These data allowed us to: quantify subterranean movement; extrapolate the three‐dimensional burrow architecture; simultaneously track multiple individuals; and establish the function of specific movement patterns; demonstrating the technique's utility. Contrasting data generated using MI tracking, against the resolution achievable with VHF tracking, we establish how sampling frequency can influence the perception of movement. Taking 20 locational fixes per minute, MI collars operated for 1 year before on‐board batteries failed, resulting in an average five billion data points per collar deployment. Socio‐ecologically we found that rather than foraging continuously throughout the night, badgers returned to the sett an average of 2·2 times, approximately every 3–4 h. From burrow mapping, badgers tended to use peripheral chambers for c . 45 min on these return visits. These outlying chambers were used less by day, when badgers selected deeper chambers, suggesting each chamber type fulfils a different function. This technology also exposed that badgers exhibited a far greater extent of underground movement than revealed by former technologies, which by comparison captured <0·5% of subterranean activity. Importantly, these high‐resolution data showed that individuals left, returned to, and moved about the sett independently, with no tendency for synchronous subterranean activity. In overview, Magneto‐Inductive tracking proved relatively simple and cost‐effective to deploy, it provided very detailed and accurate subterranean fixes, and was robust enough for long‐term field deployment. Furthermore, the capabilities of MI are highly transferable, enabling a better understanding of underground activity and the ecological importance of subterranean burrows for the conservation and management of a wide range of species.
Abstract Interspecific interactions between sympatric carnivores have important implications for intra‐guild competition, epidemiology (here especially in the context of rabies and bovine tuberculosis), and strategies for species‐specific population management. Data are provided on 135 interspecific encounters between at least 35 European badgers Meles meles and a minimum of five red foxes Vulpes vulpes , gathered with the aid of remote video surveillance at an artificial feeding site, and in the vicinity of six badger setts. We hypothesized that interspecific competition would be manifest in aggression and changes in vigilance and feeding, with the larger badger having the advantage, and we sought to explore differences in any such changes at the two types of site. Badgers were clearly dominant over foxes, fed in longer bouts and were less vigilant. At badger setts, once it was clear that the encounter was not going to escalate to aggression, each species was unaffected by the presence, proximity or orientation of the other. There are preliminary indications that foxes sometimes seek the company of badgers.
Localization of mobile devices underground is extremely challenging, with radio propagation (such as used in GPS and VHF) severely attenuated by soil and moisture. However, low frequency magnetic fields are able to penetrate the ground with minimal loss. Mobile underground tracking devices record magnetic field strengths generated by an array of transmitting coils placed above the area of interest. This information is stored in flash memory, for opportunistic upload over a conventional radio link when the device is above ground. As a particular application of this technology, the underground movements of wild European badgers (Meles meles) were tracked in 3-D within their burrow systems, by equipping them with lightweight tracking collars. Typical localization accuracy is 0.45 m RMS over a 15 m × 15 m area and collar lifetime is of the order of 9 months from a 1.4 Ah lithium cell.
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