Mount St Vincent University

Halifax, Canada

Mount St Vincent University

Halifax, Canada
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Helseth S.A.,Florida International University | Waschbusch D.A.,Florida International University | Waschbusch D.A.,Penn State Hershey Medical Center | King S.,Mount St Vincent University | Willoughby M.T.,Rti International
Journal of Abnormal Child Psychology | Year: 2015

Callous/unemotional traits (CU) moderate children’s conduct problems (CP) in numerous domains, including social functioning. The present study examined whether CU traits also moderate the aggressiveness of children’s social information processing (SIP) and responses to varying intensities of peer provocation. Sixty elementary school-age children (46 males) were grouped into those without CP or CU (controls, n = 32), those with CP but not CU (CP-only; n = 14), and those with both CP and CU (CPCU, n = 14). Participants completed a task that measured two aspects of SIP (response generation and hostile attribution bias) and a computerized reaction time task (CRTT) that measured behavior, affect, and communication before and after provocation under instrumental and hostile aggressive conditions. Children with CPCU generated more aggressive responses than controls on measures of SIP. On the CRTT, all children exhibited reactive aggression following high provocation, but only children with CPCU exhibited proactive aggression, and reactive aggression following low provocation; no differences in affect were found. In a series of exploratory analyses, CPCU children communicated antisocially, while CP-only communicated prosocially. Finally, children with CPCU did not seem to hold a grudge following the final instance of provocation, instead gradually returning to baseline like their non-CU peers. These distinct social cognitive and behavioral profiles hint at different etiologies of CP and CPCU, underscoring the variability of aggression in these populations. © 2015, Springer Science+Business Media New York.

Pottie I.R.,Memorial University of Newfoundland | Pottie I.R.,Mount St Vincent University | Nandaluru P.R.,Memorial University of Newfoundland | Bodwell G.J.,Memorial University of Newfoundland
Synlett | Year: 2011

Urolithin M7 was synthesized from 2-hydroxy-4-methoxybenzaldehyde in 8 steps and 48% overall yield. The key step was an inverse electron demand Diels-Alder (IEDDA) reaction between diene 10 and the enamine (7) derived from dimethoxyacetaldehyde and pyrrolidine, which generated the 6H-dibenzo[b,d]pyran- 6-one skeleton. © Georg Thieme Verlag Stuttgart - New York.

Kebli H.,University of Québec | Brais S.,University of Québec | Kernaghan G.,Mount St Vincent University | Drouin P.,University of Québec
Forest Ecology and Management | Year: 2012

Environmental change, including human disturbance, can have a striking impact on the biodiversity of ecosystems. We used a molecular fingerprinting technique to determine how communities of saproxylic fungi on trembling aspen deadwood change under the influence of silvicultural treatments designed to emulate natural stand dynamics. We describe changes in richness, diversity, and species composition of fungal communities of trembling aspen logs and snags caused by these silvicultural practices. Our study was conducted in the SAFE Project, a series of silvicultural experiments that tests an ecosystem management model based on natural dynamics. We found that large trembling aspen logs and in advanced decay stages had approximately 9% higher fungal species richness and 10% higher fungal diversity than small and large logs at medium decay stages. The effect of log diameter was in turn strongly dependent on the silvicultural treatment. In burned stands, larger logs supported higher fungal richness and diversity, therefore potentially acting as fungal refuge. A negative relationship between the fungal diversity of logs and snags and the volume of fine woody debris was also related to silvicultural treatments, as fine woody debris increased with silvicultural intensity. Our results underline the negative effects of intense silvicultural practice on fungal diversity and species richness by modifying community composition, but they also highlight the benefits of partial harvest, which retain coarse woody debris volume. © 2012 Elsevier B.V.

Kebli H.,University of Québec | Drouin P.,University of Québec | Brais S.,University of Québec | Kernaghan G.,Mount St Vincent University
Microbial Ecology | Year: 2011

Coarse woody debris supports large numbers of saproxylic fungal species. However, most of the current knowledge comes from Scandinavia and studies relating the effect of stand or log characteristics on the diversity and composition of decomposer fungi have not been conducted in Northeastern Canada. Logs from five tree species were sampled along a decomposition gradient in nine stands representing three successional stages of the boreal mixed forest of Northwestern Quebec, Canada. Using a molecular fingerprinting technique, we assessed fungal community Shannon-Weaver diversity index, richness, and composition. We used linear mixed models and multivariate analyses to link changes in fungal communities to log and stand characteristics. We found a total of 33 operational taxonomic units (OTUs) including an indicator species for balsam fir (similar to Athelia sp.) and one found only in aspen stands (similar to Calocera cornea). Spruce logs supported the highest fungal Shannon-Weaver diversity index and OTU number. Our results support the hypothesis that log species influences fungal richness and diversity. However, log decay class does not. Stand composition, volume of coarse woody debris, and log chemical composition were all involved in structuring fungal communities. Maintaining the diversity of wood-decomposing communities therefore requires the presence of dead wood from diverse log species. © 2011 Springer Science+Business Media, LLC.

John J.,Dalhousie University | Kernaghan G.,Mount St Vincent University | Lundholm J.,Saint Mary's University, Halifax
Urban Ecosystems | Year: 2016

The selection of plant species for use on green roofs has been based primarily on their ability to cope with the harsh climatic conditions of the urban rooftop environment. However, green roof plants must also survive in engineered substrates that often lack organic material and beneficial soil microorganisms such as mycorrhizal fungi. We review the literature on mycorrhizae in the context of green roof ecosystems, identifying aspects of green roof functioning that could be enhanced through the integration of mycorrhizal fungi. Although relatively few studies have addressed the influence of mycorrhizal symbiosis on green roof plants specifically, we include information from a variety of naturally occurring habitats with analogous growing conditions. The available literature suggests that the incorporation of mycorrhizal fungi can improve a number of green roof functional attributes, including plant diversity, drought resilience, leachate quality, nutrient use efficiency and carbon sequestration, all while reducing the need for external nutrient inputs. We present evidence that mycorrhizal fungi are of general benefit to green roof ecosystems, and can be effectively integrated into green roof design. We recommend methods for this integration and propose future research directions. © 2016 Springer Science+Business Media New York

John J.,Dalhousie University | Lundholm J.,Saint Mary's University, Halifax | Kernaghan G.,Mount St Vincent University
Ecological Engineering | Year: 2014

Green roof plants must survive hot and dry conditions in low nutrient artificial growing media. Although soil microorganisms such as arbuscular mycorrhizal fungi (AMF) can ameliorate these constraints by increasing water and mineral uptake, virtually nothing is known about the microbes associated with the roots of green roof plants. We determined levels of AMF and dark septate endophyte (DSE) colonization of plants grown for four years on an experimental green roof in Halifax, Nova Scotia. Green roof plant species included the forb Solidago bicolor, the grasses Danthonia spicata and Poa compressa and the succulent Sedum acre. We also assessed root colonization of these same species, as well as three additional succulents (Sedum spurium, Rhodiola rosea and Hylotelephium telephium), collected from their natural habitats. We further assessed the inoculum potential of a commercial green roof substrate before and after the introduction of host plants. Levels of AMF colonization were similar within plant species, regardless of collecting location (roof or field). All plant species were colonized except for the succulent S. acre, which is commonly utilized as a green roof plant. The commercial growing medium contained extremely low levels of viable AMF propagules, but this increased significantly after planting with Solidago. Conversely, all species (from roof, field and bioassay) were well colonized by DSE, which appear to differ from the AMF with respect to their pattern of dispersal onto the green roof. Although the widespread use of non-mycorrhizal succulent species such as S. acre precludes the ecosystem services provided by the AMF symbiosis, the benefits of both succulent tissue and AMF could be obtained simultaneously with careful green roof plant selection. © 2014 Elsevier B.V.

Eskritt M.,Mount St Vincent University | Ma S.,Mount St Vincent University
Memory and Cognition | Year: 2014

In the present study, we examined whether note-taking as a memory aid may provide a naturalistic example of intentional forgetting. In the first experiment, participants played Concentration, a memory card game in which the identity and location of pairs of cards need to be remembered. Before the game started, half of the participants were allowed to study the cards, and the other half made notes that were then unexpectedly taken away. No significant differences emerged between the two groups for remembering identity information, but the study group remembered significantly more location information than did the note-taking group. In a second experiment, we examined whether note-takers would show signs of proactive interference while playing Concentration repeatedly. The results indicated that they did not. The findings suggest that participants adopted an intentional-forgetting strategy when using notes to store certain types of information. © 2013 Psychonomic Society, Inc.

Kernaghan G.,Mount St Vincent University | Patriquin G.,Mount St Vincent University
Microbial Ecology | Year: 2011

Fungal root endophytes colonize root tissue concomitantly with mycorrhizal fungi, but their identities and host preferences are largely unknown. We cultured fungal endophytes from surface-sterilized Cenococcum geophilum ectomycorrhizae of Betula papyrifera, Abies balsamea, and Picea glauca from two boreal sites in eastern Canada. Isolates were initially grouped on the basis of cultural morphology and then identified by internal transcribed spacer ribosomal DNA sequencing or by PCR restriction fragment length polymorphism. Phylogenetic analysis of the sequence data revealed 31 distinct phylotypes among the isolates, comprising mainly members of the ascomycete families Helotiaceae, Dermateaceae, Myxotrichaceae, and Hyaloscyphaceae, although other fungi were also isolated. Multivariate analyses indicate a clear separation among the endophyte communities colonizing each host tree species. Some phylotypes were evenly distributed across the roots of all three host species, some were found preferentially on particular hosts, and others were isolated from single hosts only. The results indicate that fungal root endophytes of boreal trees are not randomly distributed, but instead form relatively distinct assemblages on different host tree species. © 2011 Springer Science+Business Media, LLC.

Kernaghan G.,Mount St Vincent University | Patriquin G.,Mount St Vincent University
Fungal Ecology | Year: 2015

Diverse fungal assemblages colonize the fine feeder roots of woody plants, including mycorrhizal fungi, fungal root endophytes and soil saprotrophs. The fungi co-inhabiting Cenococcum geophilum ectomycorrhizae (ECM) of Abies balsamea, Betula papyrifera and Picea glauca were studied at two boreal forest sites in Eastern Canada by direct PCR of ITS rDNA. 50 non-. Cenococcum fungal sequence types were detected, including several potentially mycorrhizal species as well as fungal root endophytes. Non-melanized ascomycetes dominated, in contrast to the dark septate endophytes (DSE) reported in most culture dependent studies. The results demonstrate significant differences in root associated fungal assemblages among the host species studied. Fungal diversity was also host dependent, with P. glauca roots supporting a more diverse community than A. balsamea. Differences in root associated fungal communities may well influence ecological interactions among host plant species. © 2015 Elsevier Ltd and The British Mycological Society.

Tharamangalam J.,Mount St Vincent University
Economic and Political Weekly | Year: 2011

While agreeing with K P Kannan's remarks on the neglected agricultural scenario of Kerala ("Agricultural Development in an Emerging Non-Agrarian Regional Economy: Kerala's Challenges", 26 February 2011), this comment challenges the author's dismissal of food insecurity in Kerala as a myth.

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