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  • The differential impact of social defeat on mice living in isolation or groups in an enriched environment: Plasma corticosterone and monoamine variations

    Resource Type:
    Article
    Creator:
    Anisman, Hymie, Audet, Marie-Claude, McQuaid, Robyn J., and Jacobson-Pick, Shlomit
    Abstract:
    Social defeat in mice is a potent stressor that promotes the development of depressive- and anxiety-like behaviours, as well as variations of neuroendocrine and brain neurotransmitter activity. Although environmental enrichment may protect against some of the adverse behavioural and biological effects of social defeat, it seems that, among male group-housed mice maintained in an enriched environment (EE), aggressive behaviours may be more readily instigated, thus promoting distress and exacerbating psychopathological features. Thus, although an EE can potentially have numerous beneficial effects, these may depend on the general conditions in which mice were raised. It was observed in the current investigations that EE group-housed BALB/cByJ mice displayed increased anxiety-like behaviours compared to their counterparts maintained in a standard environment (SE). Furthermore, in response to social defeat, EE group-housed male mice exhibited decreased weight gain, exaggerated corticosterone elevations and altered hippocampal norepinephrine utilization compared to their SE counterparts. These effects were not apparent in the individually housed EE mice and, in fact, enrichment among these mice appeared to buffer against serotonin changes induced by social defeat. It is possible that some potentially beneficial effects of enrichment were precluded among group-housed mice, possibly owing to social disturbances that might occur in these conditions. In fact, even if social interaction is an essential feature of enrichment, it seems that some of the positive effects of this housing condition might be optimal when mice are housed individually, particularly with regard to buffering the effects of social defeat.
    Date Created:
    2013-03-01

  • Publishing graduate student research in geography: the fundamentals

    Resource Type:
    Article
    Creator:
    Ballamingie, Patricia and Tudin, Susan
    Date Created:
    2013-05-01

  • An information driven hybrid evolutionary algorithm for optimal design of a Net Zero Energy House

    Resource Type:
    Article
    Creator:
    Bucking, Scott, Zmeureanu, Radu, and Athienitis, Andreas
    Abstract:
    Building Performance Simulation (BPS) is a powerful tool to estimate and reduce building energy consumption at the design stage. However, the true potential of BPS remains unrealized if trial and error simulation methods are practiced to identify combinations of parameters to reduce energy use of design alternatives. Optimization algorithms coupled with BPS is a process-orientated tool which identifies optimal building configurations using conflicting performance indicators. However, the application of optimization approaches to building design is not common practice due to time and computation requirements. This paper proposes a hybrid evolutionary algorithm which uses information gained during previous simulations to expedite and improve algorithm convergence using targeted deterministic searches. This technique is applied to a net-zero energy home case study to optimize trade-offs in passive solar gains and active solar generation using a cost constraint.
    Date Created:
    2013-08-27

  • Environmental controls of frost cracking revealed through in situ acoustic emission measurements in steep bedrock

    Resource Type:
    Article
    Creator:
    Girard, Lucas, Gruber, Stephan, Weber, Samuel, and Beutel, Jan
    Abstract:
    Frost cracking, the breakdown of rock by freezing, is one of the most important mechanical weathering processes acting on Earth's surface. Insights on the mechanisms driving frost cracking stem mainly from laboratory and theoretical studies. Transferring insights from such studies to natural conditions, involving jointed bedrock and heterogeneous thermal and hydrological properties, is a major challenge. We address this problem with simultaneous in situ measurements of acoustic emissions, used as proxy of rock damage, and rock temperature/moisture content. The 1 year data set acquired in an Alpine rock wall shows that (1) liquid water content has an important impact on freezing-induced rock damage, (2) sustained freezing can yield much stronger damage than repeated freeze-thaw cycling, and (3) that frost cracking occurs over the full range of temperatures measured extending from 0 down to -15°C. These new measurements yield a slightly different picture than previous field studies where ice segregation appears to play an important role. Key PointsRock liquid water content has an important impact on the freezing-induced damageSustained freezing can yield stronger damage than repeated freeze-thaw cyclingFrost cracking occurs on a wide range of temperatures extending from 0 to -15C
    Date Created:
    2013-05-16

  • John Gilmour's Insider Art

    Resource Type:
    Article
    Creator:
    Miller, James D. and Johnston-Miller, Mary
    Date Created:
    2013-10-11

  • Calling, Courtship, and Condition in the Fall Field Cricket, Gryllus pennsylvanicus

    Resource Type:
    Article
    Creator:
    Harrison, Sarah J., Thomson, Ian R., Bertram, Susan M., and Grant, Caitlin M.
    Abstract:
    Theoretically, sexual signals should provide honest information about mating benefits and many sexually reproducing species use honest signals when signalling to potential mates. Male crickets produce two types of acoustic mating signals: a long-distance mate attraction call and a short-range courtship call. We tested whether wild-caught fall field cricket (Gryllus pennsylvanicus) males in high condition (high residual mass or large body size) produce higher effort calls (in support of the honest signalling hypothesis). We also tested an alternative hypothesis, whether low condition males produce higher effort calls (in support of the terminal investment hypothesis). Several components of long-distance mate attraction calls honestly reflected male body size, with larger males producing louder mate attraction calls at lower carrier frequencies. Long distance mate attraction chirp rate dishonestly signalled body size, with small males producing faster chirp rates. Shortrange courtship calls dishonestly reflected male residual mass, as chirp rate and pulse rate were best explained by a curvilinear function of residual mass. By producing long-distance mate attraction calls and courtship calls with similar or higher effort compared to high condition males, low condition males (low residual mass or small body size) may increase their effort in current reproductive success at the expense of their future reproductive success, suggesting that not all sexual signals are honest.
    Date Created:
    2013-03-20

  • Interruption of Ghrelin Signaling in the PVN Increases High-Fat Diet Intake and Body Weight in Stressed & Non-Stressed C57BL6J Male Mice

    Resource Type:
    Article
    Creator:
    Isaacs, Albert M., Abizaid, Alfonso, Patterson, Zachary R., and Parno, Tamara
    Abstract:
    Chronic social stress has been associated with increased caloric intake and adiposity. These effects have been linked to stress induced changes in the secretion of ghrelin, a hormone that targets a number of brain regions to increase food intake and energy expenditure and promote increased body fat content. One of the brain sites targeted by ghrelin is the hypothalamic paraventricular nucleus (PVN), a region critical for both the regulation of the stress response and the regulation of energy balance. Given these data, we examined the contribution of ghrelin receptors in the PVN to the metabolic and behavioral changes that are seen during chronic social stress in mice. To do this, mice were implanted with cannulae attached to osmotic minipumps and delivering either vehicle or the ghrelin receptor (growth hormone secretagogue receptor) antagonist [D-Lys-3]-GHRP-6 (20 nmol/day/mouse). Following a week of recovery, half of the animals in each group were exposed to chronic social defeat stress for a period of 3 weeks whereas the other half were left undisturbed. During this time, all animals were given ad libitum access to standard laboratory chow and presented a high-fat diet for 4 h during the day. Results showed that the ghrelin receptor antagonism did not decrease stressed induced caloric intake, but paradoxically increased the intake of the high fat diet. This would suggest that ghrelin acts on the PVN to promote the intake of carbohydrate rich diets while decreasing fat intake and blockade of ghrelin receptors in the PVN leads to more consumption of foods that are high in fat.
    Date Created:
    2013-09-17

  • Inquiry-based training improves teaching effectiveness of biology teaching assistants

    Resource Type:
    Article
    Creator:
    Ellefson, Michelle R. and Hughes, William
    Abstract:
    Graduate teaching assistants (GTAs) are used extensively as undergraduate science lab instructors at universities, yet they often have having minimal instructional training and little is known about effective training methods. This blind randomized control trial study assessed the impact of two training regimens on GTA teaching effectiveness. GTAs teaching undergraduate biology labs (n = 52) completed five hours of training in either inquiry-based learning pedagogy or general instructional "best practices". GTA teaching effectiveness was evaluated using: (1) a nine-factor student evaluation of educational quality; (2) a six-factor questionnaire for student learning; and (3) course grades. Ratings from both GTAs and undergraduates indicated that indicated that the inquiry-based learning pedagogy training has a positive effect on GTA teaching effectiveness.
    Date Created:
    2013-11-11

  • Neuroplasticity and the next wave of antidepressant strategies

    Resource Type:
    Article
    Creator:
    Hayley, Shawn and Litteljohn, Darcy
    Abstract:
    Depression is a common chronic psychiatric disorder that is also often co-morbid with numerous neurological and immune diseases. Accumulating evidence indicates that disturbances of neuroplasticity occur with depression, including reductions of hippocampal neurogenesis and cortical synaptogenesis. Improper trophic support stemming from stressor-induced reductions of growth factors, most notably brain derived neurotrophic factor (BDNF), likely drives such aberrant neuroplasticity. We posit that psychological and immune stressors can interact upon a vulnerable genetic background to promote depression by disturbing BDNF and neuroplastic processes. Furthermore, the chronic and commonly relapsing nature of depression is suggested to stem from “faulty wiring” of emotional circuits driven by neuroplastic aberrations. The present review considers depression in such terms and attempts to integrate the available evidence indicating that the efficacy of current and “next wave” antidepressant treatments, whether used alone or in combination, is at least partially tied to their ability to modulate neuroplasticity. We particularly focus on the N-methyl-D-aspartate (NMDA) antagonist, ketamine, which already has well documented rapid antidepressant effects, and the trophic cytokine, erythropoietin (EPO), which we propose as a potential adjunctive antidepressant agent.
    Date Created:
    2013-10-30

  • Can convict cichlids (Amatitlania siquia) socially learn the degree of predation risk associated with novel visual cues in their environment?

    Resource Type:
    Article
    Creator:
    Barks, Patrick M. and Godin, Jean-Guy
    Abstract:
    For many animals, the ability to distinguish cues indicative of predation risk from cues unrelated to predation risk is not entirely innate, but rather is learned and improved with experience. Two pathways to such learning are possible. First, an animal could initially express antipredator behaviour toward a wide range of cues and subsequently learn which of those cues are non-threatening. Alternatively, it could initially express no antipredator behaviour toward a wide range of cues and subsequently learn which of them are threatening. While the learned recognition of threatening cues may occur either through personal interaction with a cue (asocial learning) or through observation of the behaviour of social companions toward a cue (social learning), the learned recognition of non-threatening cues seems to occur exclusively through habituation, a form of asocial learning. Here, we tested whether convict cichlid fish (Amatitlania siquia) can socially learn to recognize visual cues in their environment as either threatening or non-threatening. We exposed juvenile convict cichlids simultaneously to a novel visual cue and one of three (visual) social cues: a social cue indicative of non-risk (the sight of conspecifics that had previously been habituated to the novel cue), a social cue indicative of predation risk (the sight of conspecifics trained to fear the novel cue), or a control treatment with no social cue. The subsequent response of focal fish, when presented with the novel cue alone, was not influenced by the social cue that they had previously witnessed. We therefore did not find evidence that convict cichlids in our study could use social learning to recognize novel visual cues as either threatening or non-threatening. We consider alternative explanations for our findings.
    Date Created:
    2013-10-03

  • Covariation and repeatability of male mating effort and mating preferences in a promiscuous fish.

    Resource Type:
    Article
    Creator:
    Godin, Jean-Guy and Auld, Heather L.
    Abstract:
    Although mate choice by males does occur in nature, our understanding of its importance in driving evolutionary change remains limited compared with that for female mate choice. Recent theoretical models have shown that the evolution of male mate choice is more likely when individual variation in male mating effort and mating preferences exist and positively covary within populations. However, relatively little is known about the nature of such variation and its maintenance within natural populations. Here, using the Trinidadian guppy (Poecilia reticulata) as a model study system, we report that mating effort and mating preferences in males, based on female body length (a strong correlate of fecundity), positively covary and are significantly variable among subjects. Individual males are thus consistent, but not unanimous, in their mate choice. Both individual mating effort (including courtship effort) and mating preference were significantly repeatable. These novel findings support the assumptions and predictions of recent evolutionary models of male mate choice, and are consistent with the presence of additive genetic variation for male mate choice based on female size in our study population and thus with the opportunity for selection and further evolution of large female body size through male mate choice.
    Date Created:
    2013-10-03

  • Charting the role of the number line in mathematical development

    Resource Type:
    Article
    Creator:
    LeFevre, Jo-Anne, Kamawar, Deepthi, Jimenez Lira, Carolina, Sowinski, Carla, Cankaya, Ozlem, and Skwarchuk, Sheri-Lynn
    Abstract:
    Individuals who do well in mathematics and science also often have good spatial skills. However, the predictive direction of links between spatial abilities and mathematical learning has not been firmly established, especially for young children. In the present research, we addressed this issue using a sample from a longitudinal data set that spanned 4 years and which includes measures of mathematical performance and various cognitive skills, including spatial ability. Children were tested once in each of 4 years (Time 1, 2, 3, and 4). At Time 3 and 4, 101 children (in Grades 2, 3, or 4 at Time 3) completed mathematical measures including (a) a number line task (0–1000), (b) arithmetic, and (c) number system knowledge. Measures of spatial ability were collected at Time 1, 2, or 3. As expected, spatial ability was correlated with all of the mathematical measures at Time 3 and 4, and predicted growth in number line performance from Time 3 to Time 4. However, spatial ability did not predict growth in either arithmetic or in number system knowledge. Path analyses were used to test whether number line performance at Time 3 was predictive of arithmetic and number system knowledge at Time 4 or whether the reverse patterns were dominant. Contrary to the prediction that the number line is an important causal construct that facilitates learning arithmetic, no evidence was found that number line performance predicted growth in calculation more than calculation predicted number line growth. However, number system knowledge at Time 3 was predictive of number line performance at Time 4, independently of spatial ability. These results provide useful information about which aspects of growth in mathematical performance are (and are not) related to spatial ability and clarify the relations between number line performance and measures of arithmetic and number system knowledge.
    Date Created:
    2013-08-29

  • Flavonol-rich dark cocoa significantly decreases plasma endothelin-1 and improves cognitive responses in urban children.

    Resource Type:
    Article
    Creator:
    D'Angiulli, Amedeo, Aragón-Flores, Mariana, Mukherjee, Partha S., Cross, Janet V., Gómez-Garza, Gilberto, Zhu, Hongtu, Chao, Chih-kai, Mora-Tiscareño, Antonieta, Franco-Lira, Maricela, Engle, Randall, Jewells, Valerie, Solorio, Edelmira, Weili, Lin, Medina-Cortina, Humberto, Torres-Jardón, Ricardo, Calderón-Garcidueñas, Lilian, and Ferreira-Azevedo, Lara
    Abstract:
    Air pollution exposures are linked to systemic inflammation, cardiovascular and respiratory morbidity and mortality, neuroinflammation and neuropathology in young urbanites. In particular, most Mexico City Metropolitan Area (MCMA) children exhibit subtle cognitive deficits, and neuropathology studies show 40% of them exhibiting frontal tau hyperphosphorylation and 51% amyloid-β diffuse plaques (compared to 0% in low pollution control children). We assessed whether a short cocoa intervention can be effective in decreasing plasma endothelin 1 (ET-1) and/or inflammatory mediators in MCMA children. Thirty gram of dark cocoa with 680 mg of total flavonols were given daily for 10.11 ± 3.4 days (range 9–24 days) to 18 children (10.55 years, SD = 1.45; 11F/7M). Key metabolite ratios in frontal white matter and in hippocampus pre and during cocoa intervention were quantified by magnetic resonance spectroscopy. ET-1 significantly decreased after cocoa treatment (p = 0.0002). Fifteen children (83%) showed a marginally significant individual improvement in one or both of the applied simple short memory tasks. Endothelial dysfunction is a key feature of exposure to particulate matter (PM) and decreased endothelin-1 bioavailability is likely useful for brain function in the context of air pollution. Our findings suggest that cocoa interventions may be critical for early implementation of neuroprotection of highly exposed urban children. Multi-domain nutraceutical interventions could limit the risk for endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, cognitive deficits, structural volumetric detrimental brain effects, and the early development of the neuropathological hallmarks of Alzheimer's and Parkinson's diseases.
    Date Created:
    2013-08-02

  • Circannual changes in stress and feeding hormones and their effect on food-seeking behaviors.

    Resource Type:
    Article
    Creator:
    Holahan, Matthew, Cahill, Shaina, and Tuplin, Erin
    Abstract:
    Seasonal fluctuations in food availability show a tight association with seasonal variations in body weight and food intake. Seasonal variations in food intake, energy storage and expenditure appear to be a widespread phenomenon suggesting they may have evolved in anticipation for changing environmental demands. These cycles appear to be driven by changes in external daylength acting on neuroendocrine pathways. A number of neuroendocrine pathways, two of which are the endocrine mechanisms underlying feeding and stress, appear to show seasonal changes in both their circulating levels and reactivity. As such, variation in the level or reactivity to these hormones may be crucial factors in the control of seasonal variations in food-seeking behaviours. The present review examines the relationship between feeding behavior and seasonal changes in circulating hormones. We hypothesize that seasonal changes in circulating levels of glucocorticoids and the feeding-related hormones ghrelin and leptin contribute to seasonal fluctuations in feeding-related behaviors. This review will focus on the seasonal circulating levels of these hormones as well as sensitivity to these hormones in the modulation of food-seeking behaviors.
    Date Created:
    2013-07-23

  • The social biology professor: Effective strategies for social media engagement

    Resource Type:
    Article
    Creator:
    Katti, Madhusudan and Bertram, Susan
    Abstract:
    Evolutionary biology and ecology have always been collaborative enterprises, benefitting enormously from active communication of ideas among traditional academic networks of peers. The Internet age, with its thriving online social networks, offers new tools that can help our current generation of biologists to collaborate, and communicate with the public, more effectively. Having a dynamic web presence, being part of an active blogging, Facebook, or Google+ community, and being a strategic tweeter can help your research, teaching, and service programs. Below we outline how to be a strategically savvy and active social media scientist, and discuss some of the pitfalls to avoid wasting time. We highlight some ecologists and evolutionary biologists who are active in social media to help you understand the many ways social media can help you in your academic life.
    Date Created:
    2013-07-07

  • Adaptive Plasticity in Wild Field Cricket’s Acoustic Signaling

    Resource Type:
    Article
    Creator:
    Fitzsimmons, Lauren P., Harrison, Sarah J., Thomson, Ian R., and Bertram, Susan
    Abstract:
    Phenotypic plasticity can be adaptive when phenotypes are closely matched to changes in the environment. In crickets, rhythmic fluctuations in the biotic and abiotic environment regularly result in diel rhythms in density of sexually active individuals. Given that density strongly influences the intensity of sexual selection, we asked whether crickets exhibit plasticity in signaling behavior that aligns with these rhythmic fluctuations in the socio-sexual environment. We quantified the acoustic mate signaling behavior of wild-caught males of two cricket species, Gryllus veletis and G. pennsylvanicus. Crickets exhibited phenotypically plastic mate signaling behavior, with most males signaling more often and more attractively during the times of day when mating activity is highest in the wild. Most male G. pennsylvanicus chirped more often and louder, with shorter interpulse durations, pulse periods, chirp durations, and interchirp durations, and at slightly higher carrier frequencies during the time of the day that mating activity is highest in the wild. Similarly, most male G. veletis chirped more often, with more pulses per chirp, longer interpulse durations, pulse periods, and chirp durations, shorter interchirp durations, and at lower carrier frequencies during the time of peak mating activity in the wild. Among-male variation in signaling plasticity was high, with some males signaling in an apparently maladaptive manner. Body size explained some of the among-male variation in G. pennsylvanicus plasticity but not G. veletis plasticity. Overall, our findings suggest that crickets exhibit phenotypically plastic mate attraction signals that closely match the fluctuating socio-sexual context they experience.
    Date Created:
    2013-07-22

  • Vividness of visual imagery and incidental recall of verbal cues, when phenomenological availability

    Resource Type:
    Article
    Creator:
    Zakizadeh, Jila, Runge, Matthew, Faulkner, Andrew, D'Angiulli, Amedeo, Morcos, Selvana, and Chan, Aldrich
    Abstract:
    The relationship between vivid visual mental images and unexpected recall (incidental recall) was replicated, refined, and extended. In Experiment 1, participants were asked to generate mental images from imagery-evoking verbal cues (controlled on several verbal properties) and then, on a trial-by-trial basis, rate the vividness of their images; 30 min later, participants were surprised with a task requiring free recall of the cues. Higher vividness ratings predicted better incidental recall of the cues than individual differences (whose effect was modest). Distributional analysis of image latencies through ex-Gaussian modeling showed an inverse relation between vividness and latency. However, recall was unrelated to image latency. The follow-up Experiment 2 showed that the processes underlying trial-by-trial vividness ratings are unrelated to the Vividness of Visual Imagery Questionnaire (VVIQ), as further supported by a meta-analysis of a randomly selected sample of relevant literature. The present findings suggest that vividness may act as an index of availability of long-term sensory traces, playing a non-epiphenomenal role in facilitating the access of those memories.
    Date Created:
    2013-01-02

  • Publishing Graduate Student Research in Geography: The Fundamentals

    Resource Type:
    Article
    Creator:
    Tudin, Susan and Ballamingie, Patricia
    Abstract:
    This paper offer practical advice on publishing graduate student research within the discipline of geography, addressing the following questions: why, when, where, what, how and with whom? Section 'The paper chase' delineates the importance of publishing, identifies potential material to publish, suggests venues in which to publish and offers pragmatic advice on how to negotiate the publishing process (with regards to peers, supervisors and editors). Section 'In library resources' discusses the effective use of library resources, demystifies the significance of impact factors and elucidates the history of Open Access publishing.
    Date Created:
    2013-09-18

  • Entropy, triangulation, and point location in planar subdivisions

    Resource Type:
    Article
    Creator:
    Langerman, S., Morin, P., Dujmovic, V., Iacono, J., and Collette, S.
    Abstract:
    A data structure is presented for point location in connected planar subdivisions when the distribution of queries is known in advance. The data structure has an expected query time that is within a constant factor of optimal. More specifically, an algorithm is presented that preprocesses a connected planar subdivision, G, of size n and a query distribution, D, to produce a point location data structure for G. The expected number of point-line comparisons performed by this data structure, when the queries are distributed according to D, is H' + O(H^{1/2}+1) where H'=H'(G,D)$ is a lower bound on the expected number of point-line comparisons performed by any linear decision tree for point location in G under the query distribution D. The preprocessing algorithm runs in O(n log n) time and produces a data structure of size O(n). These results are obtained by creating a Steiner triangulation of G that has near-minimum entropy.
    Date Created:
    2013-02-25