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

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

Ultra-fast aqueous polymerisation of acrylamides by high power visible light direct photoactivation RAFT polymerisation

The effect of visible LED power (λmax = 402 nm, 451 nm) on kinetics and control of direct photoactivation RAFT polymerisations of acrylamide and dimethylacrylamide are investigated. By increasing power supplied to the LEDs from 6 to 208 W, the polymerisation time required to reach >85% conversion is reduced from 12 hours to 11 minutes for acrylamide. Similar conversions are shown to be obtainable in 5 minutes for dimethylacrylamide, all without any exogenous photoinitiator or catalyst. This increase in polymerisation rate is attributed to an increase in both photon flux and a coincident increase in polymerisation temperature at higher light intensities. With both 402 nm and 451 nm LEDs exciting the same n → π* electronic transition, little difference in rate of polymerisation is seen between the two light sources. Minimal reduction in polymerisation control is observed at high irradiation intensity for acrylamide, while an increased production of low molecular weight dead chains is observed for dimethylacrylamide. This is shown to be mitigated by controlling the polymerisation temperature to 17 °C which caused both a reduction in low molecular weight tailing and an increased polymerisation time. Visible light direct photoactivation RAFT is also shown to have application in the synthesis of ultra-high molecular weight acrylamide polymers (Mn > 1 000 000 g mol−1)

Metabolomic-based biomarker discovery for non-invasive lung cancer screening:A case study

BACKGROUND: Lung cancer (LC) is one of the leading lethal cancers worldwide, with an estimated 18.4% of all cancer deaths being attributed to the disease. Despite developments in cancer diagnosis and treatment over the previous thirty years, LC has seen little to no improvement in the overall five year survival rate after initial diagnosis. METHODS: In this paper, we extended a recent study which profiled the metabolites in sputum from patients with lung cancer and age-matched volunteers smoking controls using flow infusion electrospray ion mass spectrometry. We selected key metabolites for distinguishing between different classes of lung cancer, and employed artificial neural networks and leave-one-out cross-validation to evaluate the predictive power of the identified biomarkers. RESULTS: The neural network model showed excellent performance in classification between lung cancer and control groups with the area under the receiver operating characteristic curve of 0.99. The sensitivity and specificity of for detecting cancer from controls were 96% and 94% respectively. Furthermore, we have identified six putative metabolites that were able to discriminate between sputum samples derived from patients suffering small cell lung cancer (SCLC) and non-small cell lung cancer. These metabolites achieved excellent cross validation performance with a sensitivity of 80% and specificity of 100% for predicting SCLC. CONCLUSIONS: These results indicate that sputum metabolic profiling may have potential for screening of lung cancer and lung cancer recurrence, and may greatly improve effectiveness of clinical intervention

Cleavage of macromolecular RAFT chain transfer agents by sodium azide during characterization by aqueous GPC

Accurate and reliable analysis of polymers by GPC is vital in the field of controlled radical polymerisation. Often, water-soluble polymers are analysed by aqueous gel permeation chromatography (GPC) in a solvent containing dilute sodium azide as an anti-microbial agent. Previous reports have shown that sodium azide at high concentration is able to remove terminal CTA groups from polymer chains, producing thiol-terminated polymers. This study demonstrates that GPC sample preparation of RAFT polymers in aqueous solvents containing dilute (200 ppm) sodium azide can cause significant changes in the measured molecular weight distribution. These changes occur within hours of dissolving the polymer sample and are shown to be due to cleavage of the CTA in the polymer chain together with disulfide coupling of the resulting polymeric thiols. The extent to which this occurs is strongly dependent on the CTA attached to the polymer; an almost 10-fold difference in the rate of CTA removal is observed between different RAFT agents. The by-product of the reaction between sodium azide and RAFT polymers is also investigated and shown to be an unstable thiatriazole-functionalised Z group. The thiatriazole then degrades further to form a nitrile-functionalised Z group, N2 and elemental sulfur

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

Scanning electrochemical cell microscopy : a versatile method for highly localised corrosion related measurements on metal surfaces

The development of tools that can probe corrosion related phenomena at the (sub)microscale is recognized to be increasingly important in order to understand the surface structural factors (grain orientation, inclusions etc.) that control the (electro)chemical stability (corrosion susceptibility, pitting, passivity etc.) of metal surfaces. Herein we consider the application of scanning electrochemical cell microscopy (SECCM), a relatively new member of the electrochemical droplet cell (EDC) family, for corrosion research and demonstrate the power of this technique for resolving structure and activity at the (sub)microscale. Hundreds of spatially-resolved (2 μm droplet size) potentiodynamic polarization experiments have been carried out on the several hours timescale and correlated to complementary structural information from electron backscatter diffraction (EBSD) and energy dispersive x-ray spectroscopy (EDS) in order to determine the effect of grain orientation and inclusions on electrochemical processes at low carbon steel in neutral solution (10 mM KNO3). Through this approach, it has been shown unequivocally that for the low index planes, anodic currents in the passive region (an indicator of corrosion susceptibility) are greatest on (101) planes compared to (100) and (111) planes. Furthermore, individual sub-micron MnS inclusions have been probed and shown to undergo active dissolution followed by rapid repassivation. This study demonstrates the high versatility of SECCM and the considerable potential of this technique for addressing structure-activity problems in corrosion and electromaterials science

In-Service Performance of Emergency Shutdown Valves and Dependent Operational Relationships in the Offshore Oil and Gas Industry

Industrial process plants use emergency shutdown valves (ESDVs) as safety barriers to protect against hazardous events, bringing the plant to a safe state when potential danger is detected. These ESDVs are used extensively in offshore oil and gas processing plants and have been mandated in the design of such systems from national and international standards and legislation. This paper has used actual ESDV operating data from four mid/late life oil and gas production platforms in the North Sea to research operational relationships that are of interest to those responsible for technical management and operation of ESDVs. The first of the two relationships is between the closure time (CT) of the ESDV and the time it remains in the open position, prior to the close command. It has been hypothesised that the CT of the ESDV is affected by the length of time that it has been open prior to being closed (Time since last stroke). In addition to the general analysis of the data series, two sub-categories were created to further investigate this possible relationship for CT and these are “above mean” and “below mean”. The correlations (Pearson’s based) resulting from this analysis are in the “weak” and “very weak” categories. The second relationship investigated was the effect of very frequent closures to assess if this improves the CT. ESDV operational records for six subjects were analysed to find closures that occurred within a twenty-four hour period of each other. However, no discriminating trend was apparent where CT was impacted positively or negatively by the frequent closure group. It was concluded that the variance of ESDV closure time cannot be influenced by the technical management of the ESDV in terms of scheduling the operation of the ESDV

Assessment of demand for food under concurrent PR and FR schedules in the brushtail possum (Trichosurus Vulpecula)

The aim of this study was to compare the demand by possums for foods under different arrangements of concurrent progressive-ratio and fixed-ratio schedules of reinforcement. In Experiment 1, every possible food pair made up of berries, chicken, egg, foliage, insects, and mushroom was presented (30 pairs in total). The requirement on the progressive-ratio schedule increased within a session and the fixed-ratio was kept constant at 30. In Experiment 2, a subset of the foods from Experiment 1 were used (chicken, mushroom, egg, and berries) and in separate conditions the fixed-ratio was either 30 or 10 responses. In Experiment 3, the foods were the same as used in Experiment 2 and the progressive-ratio schedule increased every five sessions and the fixed-ratio was kept constant at 30. Exponential models of demand were applied to consumption rates to compare the parameters of initial demand, essential value and Pmax, and break point and cross point across foods. The models described the data well and consumption rates were similar when the incrementing schedules increased within- and across sessions. Demand was highest for berries, egg, and locust in Experiment 1 and egg and chicken in Experiments 2 and 3. This finding has practical implications for understanding possum food preferences in the wild as a function of other available food sources and for informing pest control strategies of potential lures