335 Works

Three-phase parabolic inhomogeneities with internal uniform stresses in plane and anti-plane elasticity

X. Wang & P. Schiavone
We examine the in-plane and anti-plane stress states inside a parabolic inhomogeneity which is bonded to an infinite matrix through an intermediate coating. The interfaces of the three-phase parabolic inhomogeneity are two confocal parabolas. The corresponding boundary value problems are studied in the physical plane rather than in the image plane. A simple condition is found that ensures that the internal stress state inside the parabolic inhomogeneity is uniform and hydrostatic. Furthermore, this condition is...

Assessing the nutritional consequences of switching foraging behaviour in wood bison

Lee Hecker, Mark Edwards & Scott Neilsen
Diet is one of the most common traits used to organize species of animals into niches. For ruminant herbivores, the breadth and uniqueness of their dietary niche is placed on a spectrum from browsers that consume woody (i.e., browse) and herbaceous (i.e., forbs) plants, to grazers with graminoid-rich diets. However, seasonal changes in plant availability and quality can lead to switching of their dietary niche, even within species. In this study, we examined whether a...

Social effects on annual fitness in red squirrels

Andrew McAdam, Quinn Webber, Ben Dantzer, Jeff Lane & Stan Boutin
When resources are limited, mean fitness is constrained and competition can cause genes and phenotypes to enhance an individual’s own fitness while reducing the fitness of their competitors. Negative social effects on fitness have the potential to constrain adaptation, but the interplay between ecological opportunity and social constraints on adaptation remains poorly studied in nature. Here, we tested for evidence of phenotypic social effects on annual fitness (survival and reproductive success) in a long-term study...

Data from: Resource exploitation collapses the home range of an apex predator

Melanie Dickie, Robert Serrouya, Avgar Tal, Philllip McLouglin, Scott McNay, Craig DeMars & Stan Boutin
Optimizing energy acquisition and expenditure is a fundamental trade-off for consumers, strikingly reflected in how mobile organisms use space. Several studies have established that home range size decreases as resource density increases, but the balance of costs and benefits associated with exploiting a given resource density is unclear. We evaluate how the ability of consumers to exploit their resources through movement (termed “resource exploitation”) interacts with resource density to influence home range size. We then...

When Deleuze and Lacan {finally} Meet :The Singularity (Life) of Art in [Art] Education

Jan Jagodzinski

Managing Risk Taking with Interest Rate Policy and Macroprudential Regulations

Simona E. Cociuba, Malik Shukayev & Alexander Ueberfeldt
We develop a model in which a financial intermediary’s investment in risky assets—risk taking—is excessive due to limited liability and deposit insurance and characterize the policy tools that implement efficient risk taking. In the calibrated model, coordinating interest rate policy with state-contingent macroprudential regulations, either capital or leverage regulation, and a tax on profits achieves efficiency. Interest rate policy mitigates excessive risk taking by altering both the return and the supply of collateralizable safe assets....

Data from: Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada's Great Bear Lake

Les N. Harris, Louise Chavarie, Robert Bajno, Kimberly L. Howland, Simon H. Wiley, William M. Tonn & Eric B. Taylor
Range expansion in north-temperate fishes subsequent to the retreat of the Wisconsinan glaciers has resulted in the rapid colonization of previously unexploited, heterogeneous habitats and, in many situations, secondary contact among conspecific lineages that were once previously isolated. Such ecological opportunity coupled with reduced competition likely promoted morphological and genetic differentiation within and among post-glacial fish populations. Discrete morphological forms existing in sympatry, for example, have now been described in many species, yet few studies...

Data from: Postcrania of juvenile Pinacosaurus grangeri (Ornithischia: Ankylosauria) from the Upper Cretaceous Alagteeg Formation, Alag Teeg, Mongolia: implications for ontogenetic allometry in ankylosaurs

Michael E. Burns, Tatiana A. Tumanova & Philip J. Currie
The ankylosaurine Pinacosaurus is one of the best known ankylosaur to date in terms of the number and preservational quality of specimens. Juvenile to sub-adult postcrania collected by the Soviet-Mongolian Paleontological Expedition from the Upper Cretaceous Alagteeg Formation at Alag Teeg, Mongolia can be assigned to Pinacosaurus grangeri based on discrete cranial characters. One individual is significantly larger than the others and demonstrates delayed fusion of postcranial elements with the earliest occurring between dorsal ribs...

Data from: Ecosystem memory of wildfires affects resilience of boreal mixedwood biodiversity after retention harvest

J.A. Colin Bergeron, Jaime Pinzon, Sonya Odsen, Samuel Bartels, S. Ellen Macdonald, John R. Spence & J. A. Colin Bergeron
The extent to which past states influence present and future ecosystem characteristics (ecosystem memory (EM)) is challenging to assess because signals of past ecological conditions fade with time. Using data about seven different taxa, we show that ecological gradients initiated by wildfires up to three centuries earlier affect biotic recovery after variable retention harvest in the boreal mixedwood forest. First, we show that fire history over the last 300 years is reflected in pre-harvest species-specific...

Data from: Genetic and genomic evidence of niche partitioning and adaptive radiation in mountain pine beetle fungal symbionts

Dario I. Ojeda Alayon, Clement K. M. Tsui, Nicolas Feau, Arnaud Capron, Braham Dhillon, Zhang Yiyuan, Sepideh Massoumi Alamouti, Celia K. Boone, Allan L. Carroll, Janice E.K. Cooke, Amanda D. Roe, Felix A. H. Sperling, Richard C. Hamelin, Janice E. K. Cooke & Yiyuan Zhang
Bark beetles form multipartite symbiotic associations with blue stain fungi (Ophiostomatales, Ascomycota). These fungal symbionts play an important role during the beetle's life cycle by providing nutritional supplementation, overcoming tree defences and modifying host tissues to favour brood development. The maintenance of stable multipartite symbioses with seemingly less competitive symbionts in similar habitats is of fundamental interest to ecology and evolution. We tested the hypothesis that the coexistence of three fungal species associated with the...

Data from: Miocene flooding events of western Amazonia

Carlos Jaramillo, Ingrid Romero, Carlos D'Apolito, German Bayona, Edward Duarte, Stephen Louwye, Jaime Escobar, Javier Luque, Jorge D. Carrillo-Briceño, Vladimir Zapata, Andrés Mora, Stefan Schouten, Michael Zavada, Guy Harrington, John Ortiz & Frank P. Wesselingh
There is a considerable controversy about whether western Amazonia was ever covered by marine waters during the Miocene [23 to 5 Ma (million years ago)]. We investigated the possible occurrence of Miocene marine incursions in the Llanos and Amazonas/Solimões basins, using sedimentological and palynological data from two sediment cores taken in eastern Colombia and northwestern Brazil together with seismic information. We observed two distinct marine intervals in the Llanos Basin, an early Miocene that lasted...

Data from: Incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape

Mark Baah-Acheamfour, Charles P. A. Bourque, Fan-Rui Meng, D. Edwin Swift & Charles P.-A. Bourque
There are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. In this paper, we present a framework for revising the potential distribution of tree species native to the Western Ecoregion of Nova Scotia, Canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (PSD). The PSD model is developed by...

Data from: Genetic decline, restoration and rescue of an isolated ungulate population

Marc-Antoine Poirier, David W. Coltman, Fanie Pelletier, Jon Jorgenson & Marco Festa-Bianchet
Isolation of small populations is expected to reduce fitness through inbreeding and loss of genetic variation, impeding population growth and compromising population persistence. Species with long generation time are the least likely to be rescued by evolution alone. Management interventions that maintain or restore genetic variation to assure population viability are consequently of significant importance. We investigated, over 27 years, the genetic and demographic consequences of a demographic bottleneck followed by artificial supplementation in an...

Data from: Natural regeneration on seismic lines influences movement behaviour of wolves and grizzly bears

Laura Finnegan, Karine E. Pigeon, Jerome Cranston, Mark Hebblewhite, Marco Musiani, Lalenia Neufeld, Fiona Schmiegelow, Julie Duval & Gordon B. Stenhouse
Across the boreal forest of Canada, habitat disturbance is the ultimate cause of caribou (Rangifer tarandus caribou) declines. Habitat restoration is a focus of caribou recovery efforts, with a goal to finding ways to reduce predator use of disturbances, and caribou-predator encounters. One of the most pervasive disturbances within caribou ranges in Alberta, Canada are seismic lines cleared for energy exploration. Seismic lines facilitate predator movement, and although vegetation on some seismic lines is regenerating,...

Data from: A generalized residual technique for analyzing complex movement models using earth mover's distance

Jonathan R. Potts, Marie Auger-Méthé, Karl Mokross & Mark A. Lewis
1. Complex systems of moving and interacting objects are ubiquitous in the natural and social sciences. Predicting their behavior often requires models that mimic these systems with sufficient accuracy, while accounting for their inherent stochasticity. Though tools exist to determine which of a set of candidate models is best relative to the others, there is currently no generic goodness-of-fit framework for testing how close the best model is to the real complex stochastic system. 2....

Worldwide evidence of a unimodal relationship between productivity and plant species richness

Lauchlan H. Fraser, Jason Pither, Anke Jentsch, Marcelo Sternberg, Martin Zobel, Diana Askarizadeh, Sandor Bartha, Carl Beierkuhnlein, Jonathan A. Bennett, Alex Bittel, Bazartseren Boldgiv, Ilsi I. Boldrini, Edward Bork, Leslie Brown, Marcelo Cabido, James Cahill, Cameron N. Carlyle, Giandiego Campetella, Stefano Chelli, Ofer Cohen, Anna-Maria Csergo, Sandra Diaz, Lucas Enrico, David Ensing, Alessandra Fidelis … & Szilárd Szentes
The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and...

Data from: Genome-wide admixture and ecological niche modeling reveal the maintenance of species boundaries despite long history of interspecific gene flow

Amanda R. De La Torre, David R. Roberts & Sally N. Aitken
1.The maintenance of species boundaries despite interspecific gene flow has been a continuous source of interest in evolutionary biology. Many hybridizing species have porous genomes with regions impermeable to introgression, conferring reproductive barriers between species. 2.We used ecological niche modeling to study the glacial and postglacial recolonization patterns between the widely hybridizing spruce species Picea glauca and P. engelmannii in western North America. 3.Genome-wide estimates of admixture based on a panel of 311 candidate gene...

Data from: High resolution mapping of community structure in three glass sponge reefs (Porifera, Hexactinellida).

Jackson W. F. Chu, Sally P. Leys, JWF Chu & SP Leys
ABSTRACT: Glass sponge reefs (Porifera, Hexactinellida) are unique to the Pacific coast of Canada. To date, the locations and extents of reefs have only been assessed by multibeam echosounders, a method that does not resolve where live, dead and buried sponges are within a reef. We performed fine-scale (25 and 12.5 m grids) photographic surveys using remote operated vehicles and carried out GIS and semivariogram analysis to produce high resolution maps of the spatial distribution...

Data from: Gα and regulator of G-protein signaling (RGS) protein pairs maintain functional compatibility and conserved interaction interfaces throughout evolution despite frequent loss of RGS proteins in plants

Dieter Hackenberg, Michael McKain, Soon-Goo Lee, Swarup Roy Choudhury, Tyler McCann, Spencer Schreier, Alex Harkess, J. Chris Pires, Gane Ka-Shu Wong, Joseph Jez, Elizabeth Kellogg, Sona Pandey, Soon Goo Lee, Joseph M. Jez, Michael R. McKain & Elizabeth A. Kellogg
Signaling pathways regulated by heterotrimeric G-proteins exist in all eukaryotes. The regulator of G-protein signaling (RGS) proteins are key interactors and critical modulators of the Gα protein of the heterotrimer. However, while G-proteins are widespread in plants, RGS proteins have been reported to be missing from the entire monocot lineage, with two exceptions. A single amino acid substitution-based adaptive coevolution of the Gα:RGS proteins was proposed to enable the loss of RGS in monocots. We...

Data from: The evolutionary history of ferns inferred from 25 low-copy nuclear genes

Carl J. Rothfels, Fay-Wei Li, Erin M. Sigel, Layne Huiet, Anders Larsson, Dylan O. Burge, Markus Ruhsam, Michael Deyholos, Douglas E. Soltis, , Shane W. Shaw, Lisa Pokorny, Tao Chen, Claude DePamphilis, Lisa DeGironimo, Li Chen, Xiaofeng Wei, Xiao Sun, Petra Korall, Dennis W. Stevenson, Sean W. Graham, Gane Ka-Shu Wong, Kathleen M. Pryer, C. Neal Stewart, Gane K-S. Wong … & Claude De Pamphilis
Premise of the study: Understanding fern (monilophyte) phylogeny and its evolutionary timescale is critical for broad investigations of the evolution of land plants, and for providing the point of comparison necessary for studying the evolution of the fern sister group, seed plants. Molecular phylogenetic investigations have revolutionized our understanding of fern phylogeny, however, to date, these studies have relied almost exclusively on plastid data. Methods: Here we take a curated phylogenomics approach to infer the...

Data from: Fine scale genetic correlates to condition and migration in a wild Cervid

Joseph M. Northrup, Aaron B. A. Shafer, , David W. Coltman, George Wittemyer & Charles R. Anderson
The relationship between genetic variation and phenotypic traits is fundamental to the study and management of natural populations. Such relationships often are investigated by assessing correlations between phenotypic traits and heterozygosity or genetic differentiation. Using an extensive data set compiled from free-ranging mule deer (Odocoileus hemionus), we combined genetic and ecological data to (i) examine correlations between genetic differentiation and migration timing, (ii) screen for mitochondrial haplotypes associated with migration timing, and (iii) test whether...

Data from: Territory surveillance and prey management: wolves keep track of space and time

Ulrike E. Schlägel, Evelyn H. Merrill & Mark A. Lewis
Identifying behavioral mechanisms that underlie observed movement patterns is difficult when animals employ sophisticated cognitive-based strategies. Such strategies may arise when timing of return visits is important, for instance to allow for resource renewal or territorial patrolling. We fitted spatially explicit random-walk models to GPS movement data of six wolves (Canis lupus; Linnaeus, 1758) from Alberta, Canada to investigate the importance of the following: (1) territorial surveillance likely related to renewal of scent marks along...

Data from: Daily energy expenditure during lactation is strongly selected in a free-living mammal

Quinn E. Fletcher, John R. Speakman, Stan Boutin, Jeffrey E. Lane, Andrew G. McAdam, Jamieson C. Gorrell, David W. Coltman & Murray M. Humphries
1. Energy expenditure is a trait of central importance in ecological and evolutionary theory. We examined the correlates of, the strength of selection on, and the heritability of, daily energy expenditure (DEE; kJ/day) during lactation in free-ranging North American red squirrels (Tamiasciurus hudsonicus). 2. Over seven years, lactating squirrels with greater DEE had higher annual reproductive success (ARS; standardized selection gradient: β’ = 0.47; top 12% of published estimates). Surprisingly, positive fecundity selection on lactation...

Data from: Functional relations between body mass and risk-taking behavior in wild great tits

Maria Moiron, Yimen G. Araya Ajoy, Kimberley J. Mathot, Alexia Mouchet, Niels J. Dingemanse & Yimen G Araya-Ajoy
Natural selection often favors particular combinations of functionally-related traits, resulting in adaptive phenotypic integration. Phenotypic integration has been proposed as a potential mechanism explaining the existence of repeatable among-individual differences in behavior (i.e., animal personality). In this study, we investigated patterns of covariation between morphology and behavior in a population of free-living great tits (Parus major) monitored for seven years. In particular, we aimed to disentangle the effect of structural size versus body condition on...

Data from: The dorid nudibranchs Peltodoris lentiginosa and Archidoris odhneri as predators of glass sponges

Jackson W.F. Chu & Sally P. Leys
The dorid nudibranchs Peltodoris lentiginosa and Archidoris odhneri were found on glass sponges (Porifera, Hexactinellida) during remotely operated vehicle surveys of three reefs in the Strait of Georgia, British Columbia, Canada. Eight nudibranchs were sampled from 2009 to 2011. Identification of sponge spicules found in their gut and fecal contents confirmed the nudibranchs to be predators of the reef-forming hexactinellids Aphrocallistes vastus and Heterochone calyx, as well as of the demosponge Desmacella austini, which encrusts...

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  • University of Alberta
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