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A role for neurogenesis in probabilistic reward learning
No full textRewards are often unreliable and optimal choice requires behavioral flexibility and learning about the probabilistic nature of uncertain rewards. Probabilistic learning occurs over multiple trials, often without conscious knowledge, and is traditionally associated with striatal function. While the hippocampus is classically recognized for its role in memory for individual experiences, recent work indicates that it is also involved in probabilistic forms of learning but little is known about the features that support such learning. We hypothesized that adult neurogenesis may be involved, because adult-born neurons contribute to both learning and reward-related behaviors. To test this, we used an appetitive probabilistic reversal learning task where a correct lever is rewarded with 80% probability and an incorrect lever is rewarded with 20% probability. Behavioral flexibility was assessed by switching correct-incorrect lever identities after 8 consecutive correct choices. Transgenic male rats that lacked adult neurogenesis displayed an initial deficit in discriminating the correct and incorrect levers, but they were not impaired at reversing behavior when the reward contingencies switched. When reward was withheld after a correct lever choice, neurogenesis-deficient rats were more likely to choose the incorrect lever on the subsequent trial. Also, rats with intact neurogenesis were more sensitive to reward at the incorrect lever. Differences were not observed in control transgenic rats that had intact neurogenesis. These results identify a novel role for neurogenesis in learning about uncertain, probabilistic rewards. Altered sensitivity to reward and negative feedback furthermore implicates neurogenesis in cognitive phenotypes associated with mood disorders such as depression
Biomass for renewable energy production in Pakistan: current state and prospects [Latest Articles]
No full textThermal degradation behavior of a new family of organometallic dendrimer [Online First Articles]
No full textDependence on interprovincial migrant labour in Atlantic Canadian communities: The role of the Alberta economy
No full textSocial Sciences and Humanities Council of Canada Insight Development Grant Progra
Experimental investigation and optimization of integrated photovoltaic and photoelectrochemical hydrogen generation
No full textThis paper examines the transport phenomena and optimal performance of an integrated concentrated photovoltaic and photoelectrochemical hydrogen reactor. Individual components and the overall system are studied experimentally including the performance of the concentrator, spectrum-splitting mirror, electrolyser, reactor, and photovoltaic module. Integrating the solar concentration with a spectrum-splitting mirror allows simultaneous photovoltaic electricity generation and direct photonic energy conversion to produce hydrogen via electrolytic and photoelectrochemical water splitting. A multi-objective optimization of the integrated system is performed with machine learning and integration of a neural network. This yields a relationship between the system inputs and outputs. The neural network is used to optimize the overall system through a genetic algorithm. Numerical and experimental results are presented and discussed in the paper.Natural Sciences and Engineering Research Council (NSERC
Temporal changes in clinical and radiographic variables in dogs with preclinical myxomatous mitral valve disease: The EPIC study
No full textBackground
The Evaluation of pimobendan in dogs with cardiomegaly caused by preclinical myxomatous mitral valve disease (EPIC) study monitored dogs with myxomatous mitral valve disease (MMVD) as they developed congestive heart failure (CHF).
Objectives
To describe the changes in clinical and radiographic variables occurring as dogs with MMVD and cardiomegaly develop CHF, compared to similar dogs that do not develop CHF.
Animals
One hundred and thirty‐five, and 73 dogs that did or did not develop CHF, respectively.
Materials and methods
The following variables were evaluated in 2 groups of dogs (dogs that did or did not develop CHF): Heart rate (HR), clinic respiratory rate (RR), home‐measured resting respiratory rate (RRR), rectal temperature (RT), body weight (BW), and vertebral heart sum (VHS). Absolute value and rate of change of each variable were calculated for each day a dog was in study. Daily means were calculated and plotted against time. The onset of CHF or last visit before leaving the study were set as reference time points.
Results
The most extreme values and rate of change occurred in variables immediately before onset of CHF. Vertebral heart sum increased earliest. Heart rate, RR, and RRR also increased. Rectal temperature and BW decreased. Increases in RR and RRR were most extreme and occurred immediately before CHF.
Conclusions and Clinical Importance
Dogs with MMVD and cardiomegaly experience increases in HR, RR, RRR, and VHS, and decreases in BW and RT as they develop CHF. The variables with highest absolute change and rate of change were RR and RRR. These findings reinforce the value of RR and RRR as indicators of impending or incipient CHF
Tick-borne diseases in dogs: A Canadian perspective
No full textPresenting the latest research on canine Lyme disease, anaplasmosis and ehrlichiosis, Tick-borne Disease in Dogs is an invaluable reference for veterinarians and dog owners. As geographic ranges of ticks and their associated vector-borne patho¬gens rapidly expand in Central, Eastern and Atlantic Canada, it is imperative to understand the complex relationships surrounding the incidence of disease in dogs to inform management and prevention. The book begins with an introduction to tick types, distribution and relevance to dogs in Canada. The following chapters outline the various pathogens for Lyme disease in dogs, anaplasmosis and ehrli¬chiosis and discuss clinical signs, diagnosis and treatment. This book concludes with a call to action for Canadian longitudinal studies and highlights the exciting research happening in Canada with the K9 Lifetime (Lyme) Study
Multi-objective optimization of an experimental integrated thermochemical cycle of hydrogen production with an artificial neural network
No full textIn this study, an experimental lab-scale copper-chlorine (Cu–Cl) cycle of hydrogen production is examined and optimized in terms of exergy efficiency and operational costs of produced hydrogen. The integrated process is modeled and simulated in Aspen Plus incorporating the reaction kinetic parameters with a sensitivity analysis of a range of operating conditions. An artificial neural network (ANN) method with machine learning is used to generate a mathematical function that is optimized based on a multi-objective genetic algorithm (MOGA) method. A sensitivity analysis of variations of each design parameter for both the objective functions and the effectiveness of exergy performance relative to operational costs of produced hydrogen is demonstrated. The sensitivity analysis and optimization results are presented and discussed.Natural Sciences and Engineering Research Council of Canad
Race to the reactor and other chemistry games: Game-based and experiential learning experiences in materials and polymer chemistry
No full textEducational games and experiential learning experiences are integral alternative learning tools, growing in popularity in postsecondary classrooms. As the introduction of green chemistry concepts, and by extension polymer chemistry, continues to grow, the need for alternative learning tools describing the synthesis, function, and design of polymers is increasing. In response, we describe a series of functional group and polymer chemistry games and hands-on activities including a card game, boardgame, and bioplastic synthesis activity. A unique group molecule building quiz is also described as a related assessment method. The activities were introduced over two years in a second-year Materials Chemistry for Engineers course, approximately 170 students per year. Overall, the activities were well received by students and provided them with an entertaining way to review first-year chemistry concepts, introduce polymer properties, and apply their own design skills to an application. Students reported the games and activities as being enjoyable as well as helpful in understanding material and polymer chemistry concepts
KIT somatic mutations and immunohistochemical expression in canine oral melanoma
No full textCanine oral melanoma (COM) is an aggressive neoplasm with a low response to therapies, sharing similarities with human mucosal melanomas. In the latter, significant alterations of the proto-oncogene KIT have been shown, while in COMs only its exon 11 has been adequately investigated. In this study, 14 formalin-fixed, paraffin-embedded COMs were selected considering the following inclusion criteria: unequivocal diagnosis, presence of healthy tissue, and a known amplification status of the gene KIT (seven samples affected and seven non-affected by amplification). The DNA was extracted and KIT target exons 13, 17, and 18 were amplified by PCR and sequenced. Immunohistochemistry (IHC) for KIT and Ki67 was performed, and a quantitative index was calculated for each protein. PCR amplification and sequencing was successful in 97.62% of cases, and no single nucleotide polymorphism (SNP) was detected in any of the exons examined, similarly to exon 11 in other studies. The immunolabeling of KIT was positive in 84.6% of the samples with a mean value of 3.1 cells in positive cases, yet there was no correlation with aberration status. Our findings confirm the hypothesis that SNPs are not a frequent event in KIT activation in COMs, with the pathway activation relying mainly on amplification