Physical Fence Research Articles

Should Dairy Cattle Be Trained to a Virtual Fence System as Individuals or in Groups?

Simple SummaryA virtual fence (VF) system is being evaluated for commercial implementation in the Australian livestock industries. For this to work in dairy systems, cows will require training to learn the association between paired stimuli for livestock containment. We aimed to understand if cow learning and response to VF stimuli would differ when trained as individuals or in groups in a controlled experimental environment. Twenty-three dairy cows were trained to a VF as individuals or in groups of 5–6, and then moved to the alternate context to test the retention of learning. Cows trained in groups were more likely to interact with the VF when tested as individuals, indicating they might rely on the response of their conspecifics rather than directly receiving stimuli themselves. It is important that all individuals learn the association between stimuli to ensure they remain within a boundary, and to minimise potential welfare implications on animals that do not learn. However, training individual cattle is impractical, therefore, further work should evaluate effective group training protocols that provide the time and space for all individuals to learn the VF. Pre-commercial virtual fence (VF) neckbands (eShepherd®, Agersens, Melbourne, Vic, Australia) can contain cows within a designated area without the need for physical fencing, through associative learning of a paired audio tone and electrical pulse. Cattle are gregarious, so there may be an impact of herd mates on the learning process. To evaluate this, a VF was set 30 m down one of three test paddocks with a feed attractant 70 m past the VF. Twenty-three Holstein-Friesian cows were all fitted with VF neckbands and trained as individuals or in groups (5–6) for four 10 min tests; then, cows were crossed over to the alternate context for two more 10 min tests. The number of cows breaking through the VF and the number of paired stimuli reduced across time (from 82% to 26% and 45% to 14%, respectively, p < 0.01). Cows trained in a group (88%) were more likely to interact with the VF in the crossover compared to those trained as individuals (36%) (p < 0.01), indicating an influence of group members on individual cow response. Individual training is impractical, therefore, future research should evaluate group training protocols ensuring all cows learn the VF to avoid any adverse impacts on animal welfare.

Intrusion recognition method based on echo state network for optical fiber perimeter security systems

In order to accurately and efficiently identify different types of intrusion signals of optical fiber perimeter security systems, this paper proposes a novel intrusion signal recognition method based on an echo state network (ESN). A perimeter security system based on an in-line Sagnac interferometer is employed to simulate in lab two laying situations of the sensing fiber: attached to a physical fence or buried under ground and acquire various event signals. The preprocessed signals are input into a trained well ESN to identify different types of events. The final recognition result of an event signal segment is determined according to the most dominant classification label corresponding to the signal segment. As a result, the average identification rates are 98.75% and 100% for the two laying situations, respectively. The proposed method has no need of extracting signal features and a large number of samples to train the classifier model. Therefore, more accurate and more effective intrusion identification can be achieved by the method than by others. The method is expected to satisfy the requirements of the practical application in the security field.

Modern Virtual Fencing Application: Monitoring and Controlling Behavior of Goats Using GPS Collars and Warning Signals.

This paper describes our virtual fence system for goats. The present invention is a method of controlling goats without visible physical fences and monitoring their condition. Control occurs through affecting goats, using one or more sound signals and electric shocks when they attempt to enter a restricted zone. One of the best Machine Learning (ML) classifications named Support Vector Machines (SVM) is used to observe the condition. A virtual fence boundary can be of any geometrical shape. A smart collar on goats’ necks can be detected by using a virtual fence application. Each smart collar consists of a global positioning system (GPS), an XBee communication module, an mp3 player, and an electrical shocker. Stimuli and classification results are presented from on-farm experiments with a goat equipped with smart collar. Using the proposed stimuli methods, we showed that the probability of a goat receiving an electrical stimulus following an audio cue (dog and emergency sounds) was low (20%) and declined over the testing period. Besides, the RBF kernel-based SVM classification model classified lying behavior with an extremely high classification accuracy (F-score of 1), whilst grazing, running, walking, and standing behaviors were also classified with a high accuracy (F-score of 0.95, 0.97, 0.81, and 0.8, respectively).

Reaching through The Fence: Howard Barker’s dramatic account of ethical subjectivity

ABSTRACTThe Fence in Its Thousandth Year (2005), a startlingly complex moral exploration with an extraordinary rich text unique to Howard Barker’s unconventional dramatic aesthetic, makes a show of how self-opacity is built into our formation as a subject and how we emerge and transform in the context of our encounters with others. Analyzing this enigmatic play within the prism of Judith Butler’s theories on recognition and identity construction in the context of moral philosophy, this essay offers original observations around subject formation in relation to Barker’s particular way of constructing characters outside the bounds of normative morality. While Butler corroborates the impossibility of giving an exhaustive account of the self and emphasises the narrative identity to be essentially fictional, Photo, Barker’s blind character in The Fence, occupies the impossible position of being present at the scene of his birth as he makes a phantasmal regression to the infantile to give a first-hand account of his own emergence. The characters’ pursuit of ecstasy gets ethical as they are compelled outside themselves to dramatise the reciprocity of giving and taking recognition. They cannot survive unless they provide a narrative account of themselves, and they mature as they give their accounts up. The Fence is a story of struggling to reach the other through physical and emotional fences and reveals unknowingness about oneself as a fundamental vulnerability in the condition of being a human.

Virtual fencing of cattle using an automated collar in a feed attractant trial

Managing grazing cattle can be challenging in environmentally-sensitive areas or when there is limited contact with and control over the animals. Virtual fences – barriers without a physical barrier – represent the potential for animal guidance in locations where physical fences may be unfeasible. In this study automated collars that provided audio and electrical stimuli to cattle were tested on 12 naïve heifers to determine if cattle could be deterred from a feed attractant in a series of 3 test paddocks. All animals were individually trained (no virtual fence line set) across 3days (each paddock once per day) to walk unrestricted down to a bale of hay. The heifers were then each fitted with the experimental prototype collar device and a virtual fence line was set across the width of each paddock to restrict animals from the hay reward. As the animal approached the virtual fence line the collar emitted a 2.5s audio cue (785Hz±15Hz, 58DB). If the animal stopped or turned away no further cues were emitted, if the animal continued forward an electrical stimulus (800V electrical pulses delivered in less than 1s) was applied immediately following the audio cue. The audio-electrical stimulus sequence was repeated as animals continued into the exclusion zone (where the hay was located). Each animal was tested in each paddock across 3days reaching a total of 8 trials when animals were no longer voluntarily approaching the hay. Logistic regression analyses showed a mean number of 6 interactions with the fence line until 50% of animals were learning to avoid the fence line based on the audio cue. The odds ratio of 1.28 (95% CI 1.14–1.44) showed that with each fence interaction, animals were 28% more likely to appropriately respond to the audio cue and avoid the electrical stimulus (Likelihood Ratio Test χ2=21.51, DF=1, P<0.0001). However, there was high variation between individual animals in their rate of learning and the behaviours they exhibited in response to both the audio and electrical stimuli. The automated collars were able to successfully exclude the majority of animals from accessing the hay but further research should aim to assess the impacts of group dynamics on individual behavioural variation and how aspects of temperament or cognition may influence learning of a virtual fencing system.

목동신시가지 아파트 단지의 공간 분리 특성

The objective of this study was to determine the reason behind the phenomenon of Mok-dong New Town, an area developed with large-scale complex. It is divided from its surrounding area although it is not following the space grammar of a gated community. In-depth interviews with residents of Mok-dong New Town were performed. Information obtained from these interviews was used to identify main elements that caused residents to divide the residential territory. Results are as follows. First and foremost, visible and invisible boundaries of the Mok-dong New Town were formed on the basis of basic units in the planning and spatial operating system used to develop the large complex. Homogeneous territories and similar landscapes assumed the role of a physical fence. Administrative system including uniformed address system, the same apartment complex name, and separate management of school districts operated as non-physical aspects of a gate. Second, invisible boundaries such as community consciousness and neighborhood relations were stronger than visual boundaries such as gates and fences in Mok-dong New Town. Lastly, the concept and elements of the large-scale complex development plan were directly bound to the Mok-dong New Town. It also formed a boundary in a secondary way through limiting the range of daily life and neighborhood relations. The significance of this study is as follows. First, collection and analysis of data of this study were based on perceptions of actual residents. Second, actual condition and operation of Korean space separation were interpreted in connection with planning elements of large apartment complexes as well as social, cultural, and institutional contexts.

Colonialism and Imperialism: Indigenous Resistance on the us/Mexico Border

The Rio Grande River became a boundary after the Mexican-American War (1846-1848), dividing families and communities living along its banks. In 2005 theusCongress began enacting legislation for the purposes of building a physical fence along theus-Mexico border. As such, this digital media project foregrounds the story of Dr. Tamez, a tribal elder and retired colonel, and her Lipan Apache Band in their fight for social justice, a fight that went to federal court, and spurred an inquiry and report by the United Nations Committee on the Elimination of Racial Discrimination, and the Inter-American Commission on Human Rights.

Escape rates and biting histories of dogs confined to their owner's property through the use of various containment methods.

OBJECTIVE To determine escape rates for dogs confined to their owner's property by various containment methods and determine whether biting history was associated with containment method. DESIGN Cross-sectional survey. SAMPLE 974 owners of 1,053 dogs. PROCEDURES Individuals patronizing pet stores in Columbus, Ohio, were recruited to complete a survey on the method they used to confine their dogs to their property and their dogs' behavior history. RESULTS Dogs were confined to their owner's property by a physical fence (821/1,053 [78.0%]), electronic fence (150/1,053 [14.2%]), or tether system (82/1,053 [7.8%]). Dogs confined by an electronic fence were more likely to have escaped (66/150 [44.0%]) than were dogs confined by a see-through fence (153/658 [23.3%]), privacy fence (38/163 [23.3%]), or tether (22/82 [26.8%]). Forty-eight (4.6%) dogs had reportedly bitten a person in the past, and 81 (7.7%) had reportedly bitten another dog, but containment method was not significantly associated with whether dogs had ever bitten a person or another dog. Greeting behavior (growling, snarling, or trying to bite) was significantly associated with a history of biting a person or another dog. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that escape rate, but not biting history, was associated with the method owners used to confine dogs to their properties. Greeting behavior was associated with biting history, suggesting that owners of dogs that growl, snarl, or attempt to bite when meeting an unfamiliar person or dog should seek assistance to prevent future bites.

The ability of ewes with lambs to learn a virtual fencing system

The Nofence technology is a GPS-based virtual fencing system designed to keep sheep within predefined borders, without using physical fences. Sheep wearing a Nofence collar receive a sound signal when crossing the virtual border and a weak electric shock if continuing to walk out from the virtual enclosure. Two experiments testing the functionality of the Nofence system and a new learning protocol is described. In Experiment 1, nine ewes with their lambs were divided into groups of three and placed in an experimental enclosure with one Nofence border. During 2 days, there was a physical fence outside the border, during Day 3 the physical fence was removed and on Day 4, the border was moved to the other end of the enclosure. The sheep received between 6 and 20 shocks with an average of 10.9±2.0 (mean±SE) per ewe during all 4 days. The number of shocks decreased from 4.38±0.63 on Day 3 (when the physical fence was removed) to 1.5±0.71 on Day 4 (when the border was moved). The ewes spent on average 3%, 6%, 46% and 9% of their time outside the border on Days 1, 2, 3 and 4, respectively. In Experiment 2, 32 ewes, with and without lambs, were divided into groups of eight and placed in an experimental enclosure. On Day 1, the enclosure was fenced with three physical fences and one virtual border, which was then increased to two virtual borders on Day 2. To continue to Day 3, when there was supposed to be three virtual borders on the enclosure, at least 50% of the ewes in a group should have received a maximum of four shocks on Day 2. None of the groups reached this learning criterion and the experiment ended after Day 2. The sheep received 4.1±0.32 shocks on Day 1 and 4.7±0.28 shocks on Day 2. In total, 71% of the ewes received the maximum number of five shocks on Day 1 and 77% on Day 2. The individual ewes spent between 0% and 69.5% of Day 1 in the exclusion zone and between 0% and 64% on Day 2. In conclusion, it is too challenging to ensure an efficient learning and hence, animal welfare cannot be secured. There were technical challenges with the collars that may have affected the results. The Nofence prototype was unable to keep the sheep within the intended borders, and thus cannot replace physical fencing for sheep.

Testing a new virtual fencing system on sheep

The aim of the present experiment was to investigate the function of a virtual fencing system, consisting of collars eliciting sound signals and weak electric shocks when a sheep crosses a global positioning system (GPS) based (virtual) border. In experiment 1, 24 ewes were individually attracted to a virtual border to determine how many animals would learn to avoid electric shocks in three repetitions. Nine of the ewes succeeded and there were large individual differences in how they responded. In experiment 2, these nine ewes were kept in a virtual enclosure, with and without a physical fence outside the border, for four days. The ewes stayed inside the intended pasture when the border was kept stationary. Moving the border resulted in the ewes escaping over the virtual border. The results from the study indicate challenges with this virtual system. This has implications for the use of animal virtual fences for commercial sheep production.

Design and Implementation of Fuzzy Event-detection Algorithm for Border Monitoring on FPGA

The use of wireless sensor networks to protect sensitive facilities or international borders has recently attracted more and more attention. It has become a high-priority issue in many countries. In addition to the physical fences built for stopping illegal intruders from crossing the border, smart fencing has been proposed to extend intrusion-detection capabilities. Event detection is a central component in numerous wireless sensor network applications. In spite of this, the area of event description has not received enough attention. The majority of current event description approaches rely on using precise values to specify event thresholds. However, these crisp values cannot adequately handle the imprecise sensor readings. Therefore, in this paper, a hybrid event-detection algorithm based on two layers of 12-bit-resolution fuzzy logic system is used, which significantly improves the accuracy of event detection. Each sensor node has sensors to improve the precision of the detection system, as well as reducing the false alarm rate especially in a noisy environment. The proposed system was modeled using Matlab and designed using VHDL. The proposed system’s VHDL code has been compared with the Matlab model, which provided very close results to this software-based controller model, and also with two other VHDL-based designs, results of which are also close and comparable to the proposed system. The proposed design is then implemented using a FPGA kit, and the prototype is connected to a graphical user interface. Finally, a testing experiment of this proposed system shows an event-detection ratio capability of 98.4 % and the false alarm ratio of 1.6 %.

Cattle Responses to a Type of Virtual Fence

Interest in developing more flexible fencing technology to improve pasture and rangeland management is increasing. The objective of this study was to test the efficacy of a new virtual fencing product and measure impact on behavior, thus potentially allowing positive development of virtual fence systems. The Boviguard (Agrifence, Henderson Products Ltd., Gloucester, UK) invisible fence is now commercially available, consisting of cow collars, a battery-based transformer, and an induction cable laid on the ground or buried in the ground. As the Boviguard collar comes close to the induction cable, a warning sound is triggered and if the animal continues to move closer, an electrical stimulus is triggered. We tested this novel system on 10 cows wearing global positioning system (GPS) collars to pinpoint location and activity sensors to gather behavioral data. Two separate exclusion zones were created consecutively in different areas of a test field, with alternate periods of control, with no fence activity, and virtual fence activation. The system successfully prevented the animals from crossing the virtual fence line. No changes in general activity or lying behavior were found. There were significant changes in the pattern of use of the rest of the field area when the fencing system was activated. When only the unactivated cable was left on the ground in a final control period, the visual cue alone deterred animals from entering the exclusion area. The trial showed the effectiveness of a collar-based electrical stimuli system. This approach to virtual fencing could provide solutions for management systems where moving fences frequently is required, such as for strip grazing, nature conservation management of specific areas and habitats, and grazers of land where physical fences are not preferred or feasible.

Intelligent Fuzzy Event Detection for Border Monitoring in Noisy Environment

The use of wireless sensor networks to protect sensitive facilities or international borders has recently attracted more and more attention [1-3]. It has become a highpriority issue in many countries. In addition to the physical fences built for stopping illegal intruders from crossing the border, smart fencing has been proposed to extend intrusion detection capabilities. Event detection is a central component in numerous wireless sensor network (WSN) applications [4, 5]. In spite of this, the area of event description has not received enough attention. The majority of current event descriptionapproaches rely on using precise values to specify event thresholds [6, 7]. However this crisp values cannot adequately handle the imprecise sensor readings. Therefore, In this paper, Event-detection algorithm based on two layers fuzzy Logicsystem (FLS) is used, which conveys the idea of using fuzzy values instead of crisp ones which significantly improves the accuracy of event detection. Each sensor node has an acoustic signal sensor and one-axis acceleration sensor to improve the precision of the detection system, as well as reducing false alarm rate specially in a noisy environment.

Inventory of fruit species and ethnobotanical aspects in Sultepec, Mexico State, Mexico

Sultepec, State of Mexico, located on the central part of Mexico, belongs to the Physiographic province “Sierra Madre del Sur” and to the Subprovince “Depresión del Balsas”. Although it is known for its floristic richness, it lacks an inventory of vascular plants, including the fruit species. The aim of this work was to elaborate a database including family, scientific name, local name, biological form, origin, use, management, production and service of the fruit species. Plants were collected continuously from June 2010 to June 2011. Subsequently, they were determined in the herbarium “Eizi Matuda” (CODAGEM) from the Facultad de Ciencias Agrícolas of the Universidad Autónoma del Estado de México. The Principal Component Analysis was performed to show that management, use, origin and biological form explained the highest variability (41%) associated to the Principal Component 1. Meanwhile, plant height showed the highest association with the Principal Component 2 (18%). There were 25 families, 43 genus and 64 species. The best represented families by their species richness were Rosaceae, Rutaceae and Mimosaceae; at the genus level prevailed Citrus (7 species). The predominant biological form were trees (76.6%); 22 species provided firewood, 11 had ornamental value, 11 possessed medicinal properties, 8 were a forage source and 7 had wood value. The services they can provide include physical fence, shade, shelter for domestic animals and windbreak trees. Most of the species (62.5%) are for sale and own consumption; 37.5% is just obtained for own consumption. The main species management was in the backyard category.

Farm characteristics in Slovene wolf habitat related to attacks on sheep

We aimed to characterize differences between sheep farms in wolf habitat in Slovenia that either suffered from wolf attacks (n=30) or not (n=30) during the pasture seasons 2008–2010. Main pasture season was from April until November. Median fenced pastures were 2.7ha and herd size was 93 sheep. The three-year period contained 288 attacks, mostly occurring in May (36), and secondly peaking in October (23). 78% of all attacks occurred at night. Significantly fewer non-attacked than attacked farms had mixed herds (17% versus 40%). Wolves killed a median of 4 sheep per attack. If herds included goats, 2 goats could be killed in addition. Sheep were driven to a night facility before dusk by 43% of non-attacked farmers, and significantly fewer attacked farms (10%). Significantly fewer attacked than non-attacked farms kept sheep in closed night barns or a separately fenced night-area (20% versus 50%). Guarding dogs (usually 2 per herd) were kept by 53% attacked and 43% non-attacked farms. Average fence height was 115cm and did not differ between attacked or non-attacked farms. 87% non-attacked farms had wire-mesh fences (either electric or not) instead of fences with horizontal single wires, which was significantly more than at attacked farms (61%). Significantly more attacked (89%) than non-attacked farms (60%) had electric fences (mobile or fixed, fixed ones could be combined with physical fences). In spite of farmers using electric fences, annual attack number was significantly higher at farms with a history of wolf attacks than at new farms (4 versus 1). Electric fences or guarding dogs as used in the study area proved ineffective: they did not prevent wolf attacks or reduce killing rates. Adoption of mesh instead of single wires, polarity alternation of live with ground wires in electric fences, and fences higher than 145cm seem improvements. However, potentially, improved fencing could also prevent sheep from breaking out, if wolves have found ways to enter the fenced area, and might result in surplus killing. Alternative strategies are: (1) to keep sheep in closed night barns and to move sheep there before dusk and (2) to research (a) wolf attack rates and feasibility of separating sheep and goat herds; (b) sheep and goat responses to predator attacks and methods that assist sheep and goats to avoid being attacked; (c) wolf deterring methods focused on systematic negative reinforcement of chasing and consumption of livestock.

Black-Yellow Fences: Multicultural Boundaries and Whiteness in the Rush Hour Franchise

The Rush Hour films disrupt the interracial buddy cop formula largely by erasing whites from the films. Despite the unconventional casting, the franchise has achieved “mainstream” popularity, which I argue is at least partly because the films construct Carter and Lee in an oppositional binary as a multiracial “odd couple,” converting Carter and Lee, the two lead detectives played by Chris Tucker and Jackie Chan, into physical embodiments of blackness and yellowness, fencing in the perimeters of whiteness. Thus, whiteness is able to remain protected and undetected in the normative center. Like a physical fence, however, the boundaries are semi-permeable, creating narrative openings to challenge whiteness. Therefore, the Rush Hour franchise protects white normality but leaves it somewhat vulnerable at the margins.

The Trespass Fallacy in Patent Law

The patent system is broken and in dire need of reform; so says the popular press, scholars, lawyers, judges, congresspersons, and even the President. One common complaint is that patents are now failing as property rights because their boundaries are not as clear as the fences that demarcate real estate — patent infringement is neither as determinate nor as efficient as trespass is for land. This Essay explains that this is a fallacious argument, suffering both empirical and logical failings. Empirically, there are no formal studies of trespass litigation rates; thus, complaints about the patent system’s indeterminacy are based solely on an idealized theory of how trespass should function, which economists identify as the “nirvana fallacy.” Furthermore, anecdotal evidence and other studies suggest that boundary disputes between landowners are neither as clear nor as determinate as patent scholars assume them to be. Logically, the comparison of patent boundaries to trespass commits what philosophers call a “category mistake.” It conflates the boundaries of an entire legal right (a patent), not with the boundaries of its conceptual counterpart (real estate), but with a single doctrine (trespass) that secures real estate only in a single dimension (physical fences). As all law students learn in their first-year Property courses, estate boundaries are defined along the dimensions of time, use, and space, as represented in doctrines like future interests, easements, nuisance, and restrictive covenants, among others. The proper conceptual analog for patent boundaries is “estate boundaries,” not fences. In sum, the trespass fallacy is driving widely accepted critiques of today’s patent system that are empirically unverified and conceptually misleading.

Can virtual fences be used to control grazing sheep?

Virtual fences (VF) are based on sensory cues delivered to domestic animals with the aim of controlling their spatial behaviour without any physical barrier. VF represent an approach for controlling the distribution of free-ranging large herbivores in large rangeland areas where the implementation of human control or the use of physical fencing is made impossible by their cost, environmental concerns or specific regulations. The potential of using VF for sheep was investigated by studying the spatial behaviour of groups of 5 or 32 ewes submitted to a commercial animal-borne VF device aimed at containing them in a defined area in a series of experiments. All tests were performed in pasture alleys virtually divided in their centre by a 4-m-wide warning/punishment zone). The ewes were introduced on one side of the zone, the other side being made attractive by the presence of tall grass (feed attractant), the presence of peers (social attractant) or being made unattractive by the presence of short grass (same feed as in the alley). In a first experiment, ewes were trained in groups of 5 with a feed attractant, following a 3-stage procedure: 30-min adaptation, 90-min training with a visual cue (three white strings above the wire of the VF) and 30-min test without a visual cue. In a second experiment, the test stage was repeated for each group with feed, social and zero attractants. In a third experiment, the test with feed attractant was performed with groups of 32 ewes comprising previously trained and equipped ewes mixed in different percentages of trained: naïve (untrained and unequipped) ewes (100 : 0, 75 : 25, 50 : 50 and 0 : 100%). One year later, this test was repeated with a feed attractant either close (30 m) or far (60 m) from the punishment zone. By increasing the distance to the feed attractant, it was anticipated that this would stimulate the conflict of motivation between feed and peers. Ewes learned readily the concept of VF after a couple of contacts with the punishment zone. In the second experiment in the test with a social attractant, a few trained ewes penetrated the VF to re-associate with peers located in the pen opposite the VF. Expression of the behaviour to challenge or cross the punishment zone differed widely among individuals. In mixed groups, naïve ewes crossed the punishment zone and lead part of their trained peers across the punishment zone, regardless of the distance of the feed attractant from the punishment zone. The results suggest that VF can be used to alter the distribution of grazing sheep within large fenced areas although they cannot replace conventional fences for absolute control.

Automated Animal Control: Can Discontinuous Monitoring and Aversive Stimulation Modify Cattle Grazing Behavior?

Grazing livestock freely select landscape resources, unless they are herded or constrained by fences. Automated animal control (AAC) systems offer an alternative to physical fences by using animal-positioning technology and aversive stimuli to deter animals from staying in sensitive environments and so limit their impact. This paper reports on a replicated field experiment completed to test whether occasional stimuli (audio cue followed by a mild electric stimulus), delivered by discontinuously activated AAC collars, could suffice to modify the grazing behavior of groups of cattle. Four groups of eight steers were confined in 8-ha rectangular paddocks that had an ad libitum supplement feeder located in one end to attract cattle. The steers' positional information was recorded continuously for 3 d using a GPS receiver encased in a collar fitted around their neck. These data were used to characterize their use of the paddocks without intervention. Subsequently a restriction zone was activated on the collars. This zone contained the supplement feeders and represented approximately 10% of the paddock area. Cattle movement was again monitored during a second 3-d period, in which the steers were subjected to discontinuous aversive stimuli (5 min of stimulation followed by a random 0–30 min interval without stimulation) if they were located inside or moved into the restriction zone. Cattle visits to the restriction zone were shorter and the return interval longer when steers were subjected to discontinuous stimulation. Overall, there was a 97% reduction in the use of the restriction zone between the first and second deployments. These results suggest that grazing impact can be drastically reduced by making a zone less desirable through discontinuous aversive stimulation. Such a discontinuous (25% of the time on) AAC system can reduce power consumption in collars and so help overcome energy supply limitations that hinder commercial AAC applications.

The SARS coronavirus E protein interacts with the PALS1 and alters tight junction formation and epithelial morphogenesis

Intercellular tight junctions define epithelial apicobasal polarity and form a physical fence which protects underlying tissues from pathogen invasions. PALS1, a tight junction-associated protein, is a member of the CRUMBS3-PALS1-PATJ polarity complex, which is crucial for the establishment and maintenance of epithelial polarity in mammals. Here we report that the carboxy-terminal domain of the SARS-CoV E small envelope protein (E) binds to human PALS1. Using co-immunoprecipitation and pull-down assays, we show that E interacts with PALS1 in mammalian cells and further demonstrate that the last four carboxy-terminal amino-acids of E form a novel PDZ-binding motif that binds to PALS1 PDZ domain. PALS1 redistributes to the virion assembly site, where E is enriched, in SARS-CoV-infected Vero E6 cells. Ectopic expression of E in MDCKII epithelial cells significantly alters cellular polarity and induces formation of cysts with multiple lumens. We show that E expression delays formation of tight junctions and affects the subcelullar distribution of the apical and tight junction markers GP135 and ZO-1, respectively. We speculate that hijacking of PALS1 by SARS-CoV E plays a determinant role in the disruption of the lung epithelium in SARS patients.