Food Preferences of the Brushtail Possum (Trichosurus vulpecula)

The common brushtail possum (Trichosurus vulpecula) has been reported to eat vegetation, fruit, invertebrates, and occasionally fungi, eggs and meat. The relative preference between food types found in the wild, however, has not been investigated systematically in a controlled laboratory study. This research investigated captive possums’ food choice using two different methods of preference assessment. The first experiment involved a single stimulus assessment of possums’ (n = 20) consumption of individually presented food items. More than 75% of possums consumed berries, locusts and mushrooms but fewer than 50% of possums consumed fivefinger, raw chicken and eggs. The second experiment that used a paired stimulus assessment to establish relative preference for those foods revealed that no single food was preferred by all possums. Overall locusts were the most preferred food, followed in order of preference by berries, egg, mushrooms, chicken and foliage. The single stimulus preference assessment confirmed the palatability of foods. The paired stimulus assessment provided a rank order of food preferences

Modeling Gambling: An Application of the Mathematical Principles of Reinforcement

The Mathematical Principles of Reinforcement (MPR) has proved a useful model for predicting and describing the behaviour of non-human animals on different schedules of reinforcement. This research tests the ability of MPR to accurately predict performance of adult humans on a simulated gambling task. A simulated electronic gaming machine was used in three experiments and gambling responses were reinforced according to series of Random Ratio schedules. In Experiment 1, when participants experienced either an ascending or descending order of ratios, rates of responding were well described by a bitonic response gradient. In Experiments 2 and 3 participants experienced either an early large win or an early large loss before experiencing a series of ratio schedule values that were presented in ascending order. Again rates of responding, expressed as a function of ratio schedule value, were well described by a bitonic response gradient. The early large loss condition produced higher response rates than the early large win condition. The bitonic response gradients of all conditions were well described by MPR via changes in the parameter a, specific activation

On the existence of self-similar spherically symmetric wave maps coupled to gravity

We present a detailed analytical study of spherically symmetric self-similar solutions in the SU(2) sigma model coupled to gravity. Using a shooting argument we prove that there is a countable family of solutions which are analytic inside the past self-similarity horizon. In addition, we show that for sufficiently small values of the coupling constant these solutions possess a regular future self-similarity horizon and thus are examples of naked singularities. One of the solutions constructed here has been recently found as the critical solution at the threshold of black hole formation.Comment: 15 pages, LaTe

Olfactory generalization in detector dogs

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Generalizing to target odor variations while retaining specificity against non-targets is crucial to the success of detector dogs under working conditions. As such, the importance of generalization should be considered in the formulation of effective training strategies. Research investigating olfactory generalization from pure singular compounds to more complex odor mixtures helps to elucidate animals’ olfactory generalization tendencies and inform ways to alter the generalization gradient by broadening or narrowing the range of stimuli to which dogs will respond. Olfactory generalization depends upon both intrinsic factors of the odors, such as concentration, as well as behavioral and cognitive factors related to training and previous experience. Based on the current research, some training factors may influence generalization. For example, using multiple target exemplars appears to be the most effective way to promote elemental processing and broaden the generalization gradient, whereas increasing the number of training instances with fewer exemplars can narrow the gradient, thereby increasing discrimination. Overall, this research area requires further attention and study to increase our understanding of olfactory generalization in dogs, particularly detector dogs, to improve training and detection outcomes

Bioremediation for heavy metal contaminated brownfields

The development of eco-friendly technologies for soil decontamination is of considerable importance in the achievement of environmental pollution control. Specifically, brownfields contaminated with heavy metals are causing concern, because the biogeochemical behavior of metals is influenced by the soil characteristics of the polluted sites. Ectomycorrhizal (ECM) symbiosis of metal resistant organisms can represent a beneficial association for the improvement of soil quality in order to re-establish vegetation in brownfields. Pine (Pinus sylvestris) growth in the presence of the ECM fungi Paxillus involutus and Pisolithus tinctorius was tested in regard to exposure at different heavy metal concentrations. Mycorrhized pine seedlings have been investigated as a bioremediation system by assessing metal uptake and distribution within plant tissues. Electron microscopy revealed metal accumulation on the surface of the colonized root, inside the root and inside the needle crown. The formation of biominerals was investigated by electron diffraction, and identified pyromorphite within plant tissue. The biominerals were extracellularly embedded in the plant cell wall with indications for mineralization during cell wall growth. Biomineralization potential was discussed in terms or bioreduction, biosorption and bioaccumulation processes that might have been involved by the investigated organisms. Since the bioremediation system proved its efficiency, the ecological implications of ECM associations have been highlighted for afforestation strategies of metal polluted sites

Food Preference Predicts Speed of Approach on a Runway Task by Dogs

The effective and quick assessment of food preference is important when attempting to identify foods that might function as effective reinforcers in dogs. In the current experiment, more highly preferred foods were expected to be associated with faster approaches in a subsequent runway task. Eight dogs experienced combinations of two of six types of raw food in a paired preference assessment. These included the dog’s staple diet, to identify a rank order of preference for the foods. A different raw food was offered as the staple in two preference tests. In the runway task, the dogs were required to walk five metres to obtain a small amount of their most preferred, least preferred or staple foods and latency of approach to the foods was recorded. The results showed that the staple foods were not preferred as highly as the other foods and that each dog displayed unique and stable preferences for the different foods. The approach latencies were faster for their most-preferred food compared to their least preferred and the staple foods. The use of a runway to assess reinforcer effectiveness combined an effortful behaviour to obtain food while also requiring the dogs to make a choice, thus precluding the need for more complicated and time-consuming methods of preference assessment. The application of this method for fast and effective identification of preferred reinforcers is currently being investigating further to inform pet owners and behavioural scientists better about simple methods that they might use to identify highly preferred foods for use as reinforcers in training and behavioural testing

Collapse of an Instanton

We construct a two parameter family of collapsing solutions to the 4+1 Yang-Mills equations and derive the dynamical law of the collapse. Our arguments indicate that this family of solutions is stable. The latter fact is also supported by numerical simulations.Comment: 17 pages, 1 figur

A Systematic Review of Emergent Learning Outcomes Produced by Foreign language Tact Training

This systematic review evaluated the effects of foreign tact training on emergent learning outcomes in ten published studies. We also conducted a meta-analysis of aggregate data from seven studies comparing outcomes of foreign tact training with other verbal operant procedures. The preliminary findings indicated foreign tact training produced criterion-level responses in 84 of 106 (79.2%) post-test probes across 37 learners and 55 evaluations of foreign tact training. The meta-analysis results revealed significantly higher within-subjects mean levels of emergent responding following foreign tact training than foreign-to-native intraverbal, native to-foreign intraverbal, and foreign listener training. Emergent outcomes for adults were not significantly greater than for children. Finally, foreign tact training was slightly more efficient than the other verbal operant procedures, although most of the differences were not statistically significant

Use of the game-based learning platform KAHOOT! to facilitate learner engagement in Animal Science students

Gamification of instructional activities is a useful approach that educators can use to promote more effective learning environments by increasing problem-solving, critical thinking and competence in the classroom. 'KAHOOT!' is an online multi-player real-time quiz game that allows students to measure learning in an engaging, immediate and entertaining manner. Lecturers can measure how well students absorb information and tailor their teaching to the next step or re-teach a concept after poor uptake by students. Seventy-two students participated in a 20-question survey about their experiences with 'KAHOOT!'. Engagement scores were correlated with assessment grades to measure if 'KAHOOT!' affected student learning and achievement. The survey was deemed statistically sound in reliability and validity testing, and a principal components analysis (PCA) revealed that the attributes were strongly linked. There was no relationship between engagement score and assessment grade, indicating that 'KAHOOT'!' did not directly increase achievement. However, assessment of individual responses identified that students found it to be a positive social learning technology as it provided a fun, competitive and immersive end to a class. The benefits of fostering engagement, enjoyment and immersion within adult learning are especially important for maintaining a level of achievement within education to ensure that students are better equipped to deal with challenges and can turn a potential failure into an opportunity to improve their scholarship. The challenge provided by this study is to identify now how to measure the value of 'fun' activities in the tertiary classroom as a reinforcer for engagement, participation and learning

Comparison of Paired- and Multiple-Stimulus Preference Assessments using a Runway Task by Dogs

Preference assessments identify foods that might be valued by an animal but do not capture differences in the magnitude of value. In combination with demand, the more effort required to acquire the commodity, the more valued and likely it is to function as an effective reinforcer for use in dog training. In the current experiment, two preference assessments' applicability was measured using a combination of choice assessment and an effortful runway task. Eight dogs experienced a paired-stimulus preference assessment and multiple stimulus without replacement preference assessments combined with a 3-m runway task. The preference assessments identified different most-preferred foods but the same least-preferred foods. The reinforcer assessment results showed that the dogs moved faster to obtain their most preferred food as identified by the multiple-stimulus-without-replacement-assessment compared to the most preferred foods identified in the paired stimulus assessment. The paired- or multiple-stimulus-without-replacement preference assessments identified highly valued foods; however, the applicability of that commodity as a reinforcer was not independent of the assessment method. To ensure accurate reinforcer identification and consistency, a preference assessment should be conducted under similar conditions to that experienced when the reinforcer is used in training. Overall, the multiple stimulus without replacement preference assessment would be more useful to trainers, owners or scientists wanting to identify high-value foods for their animals to function as effective reinforcers for the elicitation of behaviors in a training context