Showing papers by "Acadia University published in 2015"

Neonicotinoid pesticides severely affect honey bee queens

Abstract: Queen health is crucial to colony survival of social bees. Recently, queen failure has been proposed to be a major driver of managed honey bee colony losses, yet few data exist concerning effects of environmental stressors on queens. Here we demonstrate for the first time that exposure to fieldrealistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees (Apis mellifera). In pesticide-exposed queens, reproductive anatomy (ovaries) and physiology (spermathecal-stored sperm quality and quantity), rather than flight behaviour, were compromised and likely corresponded to reduced queen success (alive and producing worker offspring). This study highlights the detriments of neonicotinoids to queens of environmentally and economically important social bees, and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances.

Key questions regarding work engagement

Abstract: This article discusses the concept of work engagement and summarizes research on its most important antecedents. The authors formulate 10 key questions and shape a research agenda for engagement. In addition to the conceptual development and measurement of enduring work engagement, the authors discuss the importance of state work engagement. Further, they argue that the social context is crucial and may set the stage for a climate for engagement with an important role for management. Engaged employees conserve their own engagement through a process of job crafting. After discussing possible dark sides of engagement and the relationship between engagement and health, the article closes with a discussion of organizational interventions to increase work engagement.

Neural-Symbolic Learning and Reasoning: Contributions and Challenges

Abstract: The goal of neural-symbolic computation is to integrate robust connectionist learning and sound symbolic reasoning. With the recent advances in connectionist learning, in particular deep neural networks, forms of representation learning have emerged. However, such representations have not become useful for reasoning. Results from neural-symbolic computation have shown to offer powerful alternatives for knowledge representation, learning and reasoning in neural computation. This paper recalls the main contributions and discusses key challenges for neural-symbolic integration which have been identified at a recent Dagstuhl seminar.

Marine birds and plastic debris in Canada: a national synthesis and a way forward

Abstract: Marine plastic ingestion by seabirds was first documented in the 1960s, but over 50 years later our understanding about the prevalence, intensity, and subsequent effect of plastic pollution in the ...

Transoceanic migration by a 12 g songbird.

Abstract: Many fundamental aspects of migration remain a mystery, largely due to our inability to follow small animals over vast spatial areas. For more than 50 years, it has been hypothesized that, during autumn migration, blackpoll warblers (Setophaga striata) depart northeastern North America and undertake a non-stop flight over the Atlantic Ocean to either the Greater Antilles or the northeastern coast of South America. Using miniaturized light-level geolocators, we provide the first irrefutable evidence that the blackpoll warbler, a 12 g boreal forest songbird, completes an autumn transoceanic migration ranging from 2270 to 2770 km (mean ± s.d.: 2540 ± 257) and requiring up to 3 days (62 h ± 10) of non-stop flight. This is one of the longest non-stop overwater flights recorded for a songbird and confirms what has long been believed to be one of the most extraordinary migratory feats on the planet.

Reviewing rescaling: Strengthening the case for environmental considerations

Abstract: This article is concerned with the environmental dimensions of rescaling. Specifically, it explores debates around centralization and decentralization, introduces a key distinction between rescaling to jurisdictional spaces and ecosystem spaces, and suggests three future research trajectories: (1) analytical clarification of the differences between rescaling to natural versus jurisdictional scales; (2) examination of rescaling in light of its attendant process of creating new objects of governance; and (3) investigation of rescaling processes through a temporal lens, with the suggestion that rescaled environmental governance may be the site of some of the first and last manifestations of neoliberal governance reforms.

The presence of the top prescribed pharmaceuticals in treated sewage effluents and receiving waters in Southwest Nova Scotia, Canada

Abstract: From a list of the top prescribed drugs in Canada, 11 pharmaceuticals and two metabolites were selected for study in municipal sewage treatment plant effluents and receiving waters. Wastewater samples were collected from 16 wastewater treatment plants across Southwest Nova Scotia including the Annapolis Valley, South Shore, and Metropolitan Halifax. Samples were also collected between 100 and 200 m downstream of effluent outflows. Seven pharmaceuticals were found above μg/L levels with their highest concentrations as follows: metformin (10.6 μg/L), acetaminophen (28.9 μg/L), paraxanthine (18.2 μg/L), cotinine (3.10 μg/L), caffeine (115 μg/L), naproxen (29.1 μg/L), and venlafaxine (2.65 μg/L). Metformin, paraxanthine, caffeine, naproxen, ramipril, and venlafaxine were detected in every wastewater effluent sample. Statistical analysis revealed significant differences in pharmaceutical occurrence by treatment methods, weak dependence of pharmaceutical concentrations on populations, and the co-occurrence of some pharmaceuticals. Experimental results might indicate the limitation of primary only treatment methods in breaking down pharmaceuticals.

Automated telemetry reveals age specific differences in flight duration and speed are driven by wind conditions in a migratory songbird.

Abstract: Given that winds encountered on migration could theoretically double or half the energy expenditure of aerial migrants, there should be strong selection on behaviour in relation to wind conditions aloft. However, evidence suggests that juvenile songbirds are less choosy about wind conditions at departure relative to adults, potentially increasing energy expenditure during flight. To date, there has yet to be a direct comparison of flight efficiency between free-living adult and juvenile songbirds during migration in relation to wind conditions aloft, likely because of the challenges of following known aged individual songbirds during flight. We used an automated digital telemetry array to compare the flight efficiency of adult and juvenile Savannah sparrows (Passerculus sandwichensis) as they flew nearly 100 km during two successive stages of their fall migration; a departure flight from their breeding grounds out over the ocean and then a migratory flight along a coast. Using a multilevel path modelling framework, we evaluated the effects of age, flight stage, tailwind component, and crosswind component on flight duration and groundspeed. We found that juveniles departed under wind conditions that were less supportive relative to adults and that this resulted in juveniles taking 1.4 times longer to complete the same flight trajectories as adults. We did not find an effect of age on flight duration or groundspeed after controlling for wind conditions aloft, suggesting that both age groups were flying at similar airspeeds. We also found that groundspeeds were 1.7 times faster along the coast than over the ocean given more favourable tailwinds along the coast and because birds appeared to be climbing in altitude over the ocean, diverting some energy from horizontal to vertical movement. Our results provide the first evidence that adult songbirds have considerably more efficient migratory flights than juveniles, and that this efficiency is driven by the selection of more supportive tailwind conditions aloft. We suggest that the tendency for juveniles to be less choosy about wind conditions at departure relative to adults could be adaptive if the benefits of having a more flexible departure schedule exceed the time and energy savings realized during flight with more supportive winds.

Late Paleozoic strike‐slip faults in Maritime Canada and their role in the reconfiguration of the northern Appalachian orogen

Abstract: Major late Paleozoic faults, many with documented strike-slip motion, have dissected the Ordovician-Devonian Appalachian orogen in the Maritime Provinces of Atlantic Canada. Activity alternated between east-west faults (Minas trend) and NE-SW faults (Appalachian trend). NW-SE faults (Canso trend) were probably conjugate to Minas-trend faults. Major dextral movement, on faults with Appalachian trend, in total between 200 and 300 km, began in the Late Devonian. This movement initiated the Maritimes Basin in a transtensional environment at a releasing bend formed around a promontory in the Laurentian margin and thinned the crust, accounting for the major subsidence of the basin. Appalachian-trend strike slip continued in the Mississippian but was accompanied by major movement on E-W Minas-trend faults culminating around the Mississippian-Pennsylvanian boundary, juxtaposing the Meguma and Avalon terranes of the Appalachians close to their present-day configuration. However, strike slip continued during the Pennsylvanian-Permian interval resulting in transpressional deformation that reactivated and inverted earlier extensional faults. A final major episode of transtension, mainly sinistral, occurred during the Mesozoic opening of the Atlantic Ocean. Restoration of movements on these faults, amounting to several hundred kilometers of slip, explains anomalies in the present-day distribution of terranes amalgamated during early Paleozoic Appalachian tectonism. In the restored geometry, the Nashoba and Ellsworth terranes of Ganderia are adjacent to one another, and the Meguma terrane lies clearly outboard of Avalonia. A restored post-Acadian paleogeography, not the present-day geometry of the orogen, should be used as a basis for reconstructions of its earlier Paleozoic history.

Plant Essential Oils Synergize and Antagonize Toxicity of Different Conventional Insecticides against Myzus persicae (Hemiptera: Aphididae).

Abstract: Plant-derived products can play an important role in pest management programs. Essential oils from Lavandula angustifolia (lavender) and Thymus vulgaris (thyme) and their main constituents, linalool and thymol, respectively, were evaluated for insecticidal activity and synergistic action in combination with insecticides against green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). The essential oils and their main constituents exerted similar insecticidal activity when aphids were exposed by direct sprays, but were non-toxic by exposure to treated leaf discs. In synergism experiments, the toxicity of imidacloprid was synergized 16- to 20-fold by L. angustifolia and T. vulgaris essential oils, but far less synergism occurred with linalool and thymol, indicating that secondary constituents of the oils were probably responsible for the observed synergism. In contrast to results with imidacloprid, the insecticidal activity of spirotetramat was antagonized by L. angustifolia and T. vulgaris essential oils, and linalool and thymol. Our results demonstrate the potential of plant essential oils as synergists of insecticides, but show that antagonistic action against certain insecticides may occur.

Atypical mitochondrial inheritance patterns in eukaryotes

Abstract: Mitochondrial DNA (mtDNA) is predominantly maternally inherited in eukaryotes. Diverse molecular mechanisms underlying the phenomenon of strict maternal inheritance (SMI) of mtDNA have been described, but the evolutionary forces responsible for its predominance in eukaryotes remain to be elucidated. Exceptions to SMI have been reported in diverse eukaryotic taxa, leading to the prediction that several distinct molecular mechanisms controlling mtDNA transmission are present among the eukaryotes. We propose that these mechanisms will be better understood by studying the deviations from the predominating pattern of SMI. This minireview summarizes studies on eukaryote species with unusual or rare mitochondrial inheritance patterns, i.e., other than the predominant SMI pattern, such as maternal inheritance of stable heteroplasmy, paternal leakage of mtDNA, biparental and strictly paternal inheritance, and doubly uniparental inheritance of mtDNA. The potential genes and mechanisms involved in controlling mitochondrial inheritance in these organisms are discussed. The linkage between mitochondrial inheritance and sex determination is also discussed, given that the atypical systems of mtDNA inheritance examined in this minireview are frequently found in organisms with uncommon sexual systems such as gynodioecy, monoecy, or andromonoecy. The potential of deviations from SMI for facilitating a better understanding of a number of fundamental questions in biology, such as the evolution of mtDNA inheritance, the coevolution of nuclear and mitochondrial genomes, and, perhaps, the role of mitochondria in sex determination, is considerable.

Adsorption of doxorubicin on citrate-capped gold nanoparticles: insights into engineering potent chemotherapeutic delivery systems

Abstract: Gold nanomaterials have received great interest for their use in cancer theranostic applications over the past two decades. Many gold nanoparticle-based drug delivery system designs rely on adsorbed ligands such as DNA or cleavable linkers to load therapeutic cargo. The heightened research interest was recently demonstrated in the simple design of nanoparticle-drug conjugates wherein drug molecules are directly adsorbed onto the as-synthesized nanoparticle surface. The potent chemotherapeutic, doxorubicin often serves as a model drug for gold nanoparticle-based delivery platforms; however, the specific interaction facilitating adsorption in this system remains understudied. Here, for the first time, we propose empirical and theoretical evidence suggestive of the main adsorption process where (1) hydrophobic forces drive doxorubicin towards the gold nanoparticle surface before (2) cation-π interactions and gold-carbonyl coordination between the drug molecule and the cations on AuNP surface facilitate DOX adsorption. In addition, biologically relevant compounds, such as serum albumin and glutathione, were shown to enhance desorption of loaded drug molecules from AuNP at physiologically relevant concentrations, providing insight into the drug release and in vivo stability of such drug conjugates.

Effects of Predation on Telemetry-Based Survival Estimates: Insights from a Study on Endangered Atlantic Salmon Smolts

Abstract: Telemetry is increasingly being used to estimate population-level survival rates. However, these estimates may be affected by the detectability of telemetry tags and are reliant on the assumption t...

Individual and organizational factors promoting successful responses to workplace conflict

Abstract: Although conflict at work is a fairly common and often distressing occurrence, it is arguably a vital and necessary element of human interaction. Relevant to this special issue on positive psychology, we propose that the necessary short-term intensity of interpersonal conflict can bring about positive longer term consequences, including insight, connection, and strength. We synthesize research from organisational, family, social, and personality psychology identifying factors that support successful conflict responses. Individual factors of cognitive flexibility, an appropriate balance of self- other focus, emotion regulation, and fit of the person to the conflict situation show promise for conflict success and appear to be trainable. Organisational interventions, including individual training, work group conflict training, and mediation, also demonstrate efficacy in building conflict skills. We conclude by proposing implications for conflict resolution interventions and critical directions for future research.Keywords: conflict resolution, interpersonal conflict, personality, organizational interventions, negotiationResumeLes conflits au travail sont plutot courants et sources de stress, mais ils demeurent peut-etre un element vital et necessaire des interactions humaines. Dans le cadre de cette livraison speciale sur la psychologie positive, nous proposons que l'intensite a court terme et necessaire qui caracterise les conflits interpersonnels peut resulter en des consequences positives a long terme, tels que la lucidite, des rapports et la force. L'article fait la synthese de recherches sur la psychologie organisationnelle, familiale, sociale et de la personnalite en vue de determiner les facteurs qui favorisent des reponses favorables aux conflits. Des caracteristiques individuelles, telles que la flexibilite cognitive, l'equilibre entre la focalisation sur soi et sur les autres, la maitrise des emotions et l'adaptation de la personne a la situation conflictuelle, constituent des elements prometteurs pour un conflit productif, des facteurs qui semblent s'apprendre. Les interventions organisationnelles, notamment la formation individuelle, la formation en groupes sur les conflits et la mediation, se revelent aussi efficaces dans l'acquisition de competences a composer avec les conflits. L'article se termine par des propositions d'implications pour les interventions de resolution de conflits et d'orientations determinantes pour les recherches futures.Mots-cles : resolution de conflits, conflit interpersonnel, personnalite, interventions organisationnelles, negociations.Organisational conflict has been defined in a multitude of ways, but a comprehensive definition is as follows:a state of social discord characterised by negative affect (e.g., frustration, anger, and anxiety) and the perception of interpersonal dissonance. People at work are in a state of conflict when one or more parties perceive that an ongoing or unresolved dispute poses a threat to any core human state (e.g., one's interests, identity, security, or sense of inclusion). (LeBlanc, Gilin Oore, & Axelrod, 2014,p.6).Psychological research on organisational conflict often differentiates two subtypes of conflict in work groups: task conflict (disagreements about tasks) versus relationship conflict (interpersonal friction, personality clashes; Jehn, 1995). As might be expected from this definition, research is clear that a high frequency of relationship conflict within a work group is detrimental (de Wit, Greer, & Jehn, 2012). Work groups with high relationship conflict show greater turnover, absenteeism, and work dissatisfaction; have lower team productivity (Ayoko, Callan, & Hartel, 2003; Chiaburu & Harrison, 2008; van Vianen & De Dreu, 2001); and show increased reactivity to job stressors (Gilin Oore et al., 2010) compared with work teams that have lower relationship conflict.Poorly handled organisational conflict is commonplace, and is costly in both economic and human terms. …

Adult and hatch-year blackpoll warblers exhibit radically different regional-scale movements during post-fledging dispersal

Abstract: Using a broad-scale automated telemetry array, we explored post-fledging movements of blackpoll warblers breeding in Atlantic Canada. We sought to determine the full spatial scale of post-fledging dispersal, to assess support for three hypotheses for regional-scale post-fledging movement, and to determine whether learning influenced movement during this period. We demonstrated that both young and adults moved over distances more than 200 km prior to initiating migration. Adults moved southwest, crossing the Gulf of Maine (GOM), consistent with the commencement of migration hypothesis. Hatch-year birds exhibited less directional movements constrained geographically by the GOM. Their movements were most consistent with exploration hypotheses—that young birds develop a regional-scale map to aid in habitat selection, natal dispersal and subsequent migrations.

A multilevel investigation on nursing turnover intention: the cross‐level role of leader–member exchange

Abstract: Aim To analyse nursing turnover intention from the unit by using multilevel approach, examining at the individual level, the relationships between job characteristics, job satisfaction and turnover intention, and at the group level the role of leader–member exchange. Background Research on nursing turnover has given little attention to the effects of multilevel factors. Method Aggregated data of 935 nurses nested within 74 teams of four Italian hospitals were collected in 2009 via a self-administered questionnaire. Results Hierarchical linear modelling showed that job satisfaction mediated the relationship between job characteristics and intention to leave at the individual level. At the unit level, leader–member exchange was directly linked to intention to leave. Furthermore, cross-level interaction revealed that leader–member exchange moderated the relationship between job characteristics and job satisfaction. Conclusion This study supported previous research in single-level turnover studies concerning the key role of job satisfaction, providing evidence that job characteristics are important in creating motivating and satisfying jobs. At the unit-level, leader–member exchange offers an approach to understand the role of unit-specific conditions created by leaders on nurses' workplace wellbeing. Implications for nursing management This study showed that it is important for nursing managers to recognise the relevance of implementing management practices that foster healthy workplaces centred on high-quality nurse–supervisor relationships.

Tracking the fidelity of Atlantic bluefin tuna released in Canadian waters to the Gulf of Mexico spawning grounds

Abstract: The objective of this study was to advance the use of pop-up satellite archival tags to track the migrations of Atlantic bluefin tuna (Thunnus thynnus) to their spawning grounds. Deployment of tags...

Survey of key concepts in enactivist theory and methodology

Abstract: This article discusses key concepts within enactivist writing, focussing especially on concepts involved in the enactivist description of cognition as embodied action: perceptually guided action, embodiment, and structural coupling through recurrent sensorimotor patterns. Other concepts on which these concepts depend are also discussed, including structural determinism, operational closure, autonomy, autopoiesis, consensual domains, and cognition as effective action. Some related concepts that follow from an enactivist view of cognition are considered, in particular bringing forth a world and languaging. The use of enactivism as a methodology in mathematics education is also outlined. References to mathematics education research reported in this issue and elsewhere are used throughout to provide illustrations.