71 Works

Good Volatility, Bad Volatility and Option Pricing

Bruno Feunou & Cédric Okou
Advances in variance analysis permit the splitting of the total quadratic variation of a jump diffusion process into upside and downside components. Recent studies establish that this decomposition enhances volatility predictions, and highlight the upside/downside variance spread as a driver of the asymmetry in stock price distributions. To appraise the economic gain of this decomposition, we design a new and flexible option pricing model in which the underlying asset price exhibits distinct upside and downside...

Data from: Near infrared spectroscopy (NIRS) predicts non-structural carbohydrate concentrations in different tissue types of a broad range of tree species

Jorge A. Ramirez, Juan M. Posada, I. Tanya Handa, Günter Hoch, Michael Vohland, Christian Messier & Björn Reu
1. The allocation of non-structural carbohydrates (NSCs) to reserves constitutes an important physiological mechanism associated with tree growth and survival. However, procedures for measuring NSC in plant tissue are expensive and time-consuming. Near-infrared spectroscopy (NIRS) is a high-throughput technology that has the potential to infer the concentration of organic constituents for a large number of samples in a rapid and inexpensive way based on empirical calibrations with chemical analysis. 2. The main objectives of this...

Quantifying heritability and estimating evolutionary potential in the wild when individuals that share genes also share environments

Laura Gervais, Nicolas Morellet, Ingrid David, Mark Hewison, Denis Reale, Michel Goulard, Yannick Chaval, Bruno Lourtet, Bruno Cargnelutti, Joel Merlet, Erwan Quéméré & Benoit Pujol
Accurate heritability estimates for fitness-related traits are required to predict an organism’s ability to respond to global change. Heritability estimates are theoretically expected to be inflated if, due to limited dispersal, individuals that share genes are also likely to share similar environments. However, if relatives occupy similar environments due, at least partly, to genetic variation for habitat selection, then accounting for environmental similarity in quantitative genetic models may result in diminished heritability estimates in wild...

Data from: Enhanced light interception and light use efficiency explain overyielding in young tree communities

Laura Williams, Ethan Butler, Jeannine Cavender-Bares, Artur Stefanski, Karen Rice, Christian Messier, Alain Paquette & Peter Reich
Diverse plant communities are often more productive than mono-specific ones. Several possible mechanisms underlie this phenomenon but their relative importance is unknown. Here we investigated whether light interception alone or in combination with light use efficiency (LUE) of dominant and subordinate species explained greater productivity of mixtures relative to monocultures (i.e. overyielding) in 108 young experimental tree communities. We found mixed-species communities that intercepted more light than their corresponding monocultures had 84% probability of overyielding....

Data from: Small population size and low genomic diversity have no effect on fitness in experimental translocations of a wild fish

Matthew Yates, Ella Bowles & Dylan Fraser
Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size...

Data from: Exploration profiles drive activity patterns and temporal niche specialization in a wild rodent

Elouana Gharnit, Patrick Bergeron, Dany Garant & Denis Réale
Individual niche specialization can have important consequences for competition, fitness, and ultimately population dynamics and ecological speciation. The temporal window and the level of daily activity are niche components that may vary with sex, breeding season, food supply, population density, and predator’s circadian rhythm. More recently, ecologists emphasized that traits such as dispersal and space use could depend on personality differences. Boldness and exploration have been shown to correlate with variation in foraging patterns, habitat...

Data from: Habitat-based polymorphism is common in stream fishes

Caroline Senay, Daniel Boisclair & Pedro R. Peres-Neto
1. Morphological differences (size and shape) across habitats are common in lake fish where differences relate to two dominant contrasting habitats: the pelagic and littoral habitat. Repeated occurrence of littoral and pelagic morphs across multiple populations of several lake fish species has been considered as important evidence that polymorphism is adaptive in these systems. It has been suggested that these habitat-based polymorphic differences are due to the temporal stability of the differences between littoral and...

Data from: Many places called home: the adaptive value of seasonal adjustments in range fidelity

Alexandre Lafontaine, Pierre Drapeau, Daniel Fortin & Martin-Hugues St-Laurent
1. The vast majority of animal species display range fidelity, a space-use behaviour enhancing familiarity with local habitat features. While the fitness benefits of this behaviour have been demonstrated in a variety of taxa, some species or populations rather display infidelity, displacing their home range over time. Others, such as many ungulate species, show seasonal adjustments in their range fidelity to accommodate changes in the dominance of limiting factors or in the distribution of resources....

Évaluer la production « spontanée » de récits oraux au secondaire obligatoire : Un design de validation d’outils d’évaluation

Roxane Gagnon, Sonia Guillemin, Caroline Ducrey-Évequoz, José Ticon & Rosalie Bourdages
Dans cet article, nous nous focalisons sur la portion du projet de recherche design consacrée à la conception-expérimentation d’une séquence portant sur la transformation d’une nouvelle très courte en un récit oral destiné à des élèves de secondaire 1. La contribution cherche à penser la didactisation et l’évaluation du court récit oral spontané. Nous abordons la question de la réception des outils d’évaluation par les enseignants. Notre analyse révèle que les enseignants reconnaissent la pertinence...

Data from: A quantitative framework to estimate the relative importance of environment, spatial variation and patch connectivity in driving community composition

Viviane F. Monteiro, Paulo C. Paiva & Pedro R. Peres-Neto
Perhaps the most widely used quantitative approach in metacommunity ecology is the estimation of the importance of local environment vs. spatial structuring using the variation partitioning framework. Contrary to metapopulation models, however, current empirical studies of metacommunity structure using variation partitioning assume a space-for-dispersal substitution due to the lack of analytical frameworks that incorporate patch connectivity predictors of dispersal dynamics. Here, a method is presented that allows estimating the relative importance of environment, spatial variation...

Data from: Environmental conditions affect spatial genetic structures and dispersal patterns in a solitary rodent

Gabrielle Dubuc Messier, Dany Garant, Patrick Bergeron & Denis Réale
The study of the spatial distribution of relatives in a population under contrasted environmental conditions provides critical insights into the flexibility of dispersal behaviour and the role of environmental conditions in shaping population relatedness and social structure. Yet few studies have evaluated the effects of fluctuating environmental conditions on relatedness structure of solitary species in the wild. The aim of this study was to determine the impact of interannual variations in environmental conditions on the...

Data from: Forest productivity mitigates human disturbance effects on late-seral prey exposed to apparent competitors and predators

Daniel Fortin, Florian Barnier, Pierre Drapeau, Thierry Duchesne, Claude Dussault, Sandra Heppell, Marie-Caroline Prima, Martin-Hugues St-Laurent & Guillaume Szor
Primary production can determine the outcome of management actions on ecosystem properties, thereby defining sustainable management. Yet human agencies commonly overlook spatio-temporal variations in productivity by recommending fixed resource extraction thresholds. We studied the influence of forest productivity on habitat disturbance levels that boreal caribou – a threatened, late-seral ungulate under top-down control – should be able to withstand. Based on 10 years of boreal caribou monitoring, we found that adult survival and recruitment to...

Downside Variance Risk Premium

Bruno Feunou, Mohammad R. Jahan-Parvar & Cédric Okou
We decompose the variance risk premium into upside and downside variance risk premia. These components reflect market compensation for changes in good and bad uncertainties. Their difference is a measure of the skewness risk premium (SRP), which captures asymmetric views on favorable versus undesirable risks. Empirically, we establish that the downside variance risk premium (DVRP) is the main component of the variance risk premium. We find a positive and significant link between the DVRP and...

Repenser le rapport salarial comme captation de puissance grâce à Spinoza

Sébastien Burdalski

Data from: Global macroevolution and macroecology of passerine song

William David Pearse, Ignacio Morales-Castilla, Logan S. James, Maxwell Farrell, Frédéric Boivin & T. Jonathan Davies
Studying the macroevolution of the songs of Passeriformes (perching birds) has proved challenging. The complexity of the task stems not just from the macroevolutionary and macroecological challenge of modelling so many species, but also from the difficulty in collecting and quantifying birdsong itself. Using machine learning techniques, we extracted songs from a large citizen science dataset, and then analysed the evolution, and biotic and abiotic predictors of variation in birdsong across 578 passerine species. Contrary...

Trophic structure and mercury transfer in the subarctic fish community of Great Slave Lake, Northwest Territories, Canada

John Chételat, Jillian Rohonczy, Peter A. Cott, Amanda Benwell, Mark R. Forbes, Stacey A. Robinson, Maikel R. Rosabal & Marc Amyot
In recent decades, mercury concentrations have increased in fish of Great Slave Lake (GSL), a subarctic great lake in northern Canada with important recreational, subsistence, and commercial fisheries. This study characterized habitat use and trophic position of common fish species in GSL near the City of Yellowknife (Northwest Territories, Canada), measured mercury concentrations in water and in taxa from lower trophic levels of the food web, and examined trophic and biological influences on mercury concentrations...

Data From: Evaluating the correlation between genome-wide diversity and the release of plastic phenotypic variation in experimental translocations to novel natural environments

Matthew Yates & Dylan Fraser
Phenotypic reaction norms are often shaped and constrained by selection and are important for allowing organisms to respond to environmental change. However, selection cannot constrain reaction norms for environmental conditions that populations have not experienced. This may allow cryptic neutral genetic variation for the reaction norm to accumulate such that a release of phenotypic variation occurs when it is exposed to novel conditions. Most genomic diversity behaves as if functionally neutral. Genome-wide diversity metrics may...

Effects of chronic and acute predation risk on sexual ornamentation and mating preferences

Joachim G. Frommen, Timo Thuenken, Francesca Santostefano, Valentina Balzarini & Attila Hettyey
Phenotypic plasticity is wide-spread in animals, but how plastic responses to predation threat affect traits under sexual selection and influence mating preferences is not well understood. Here, we examined how chronic predation risk during development and acute predation risk during mate choice affect the expression of male secondary sexual traits and female mating preference in the three-spined stickleback, Gasterosteus aculeatus. Males reared under chronic predation risk developed less intense red breeding colouration but showed higher...

Tree identity and diversity directly affect soil moisture and temperature but not soil carbon ten years after planting

Marc-Olivier Martin-Guay, Michaël Belluau, Benoît Côté, Ira Tanya Handa, Mark Jewell, Rim Khlifa, Alison Munson, Maxime Rivest, Joann Whalen & David Rivest
1. Soil C is the largest C pool in forest ecosystems that contributes to C sequestration and mitigates climate change. Tree diversity enhances forest productivity, so diversifying the tree species composition, notably in managed forests, could increase the quantity of organic matter being transferred to soils, and alter other soil properties relevant to the C cycle. 2. A ten-year-old tree diversity experiment was used to study the effects of tree identity and diversity (functional and...

Cross-biome synthesis of source versus sink limits to tree growth

Antoine Cabon, Steven A. Kannenberg, Flurin Babst, Dennis Baldocchi, Soumaya Belmecheri, Nicolas Delpierre, Rossella Guerrieri, Justin Maxwell, Shawn McKenzie, Chritoforos Pappas, Adrian Rocha, Paul Szejner, Masahito Ueyama, Danielle Ulrich, Caroline Vincke, Jingshu Wei, David Woodruff, Altaf Arain, Rick Meinzer, David J. P. Moore, Steven L. Voelker, William R. L. Anderegg & Frederick C. Meinzer
Uncertainties surrounding tree carbon allocation to growth are a major limitation to projections of forest carbon sequestration and response to climate change. The prevalence and extent to which carbon assimilation (source) or cambial activity (sink) mediate wood production are fundamentally important and remain elusive. We quantified source-sink relations across biomes by combining eddy-covariance gross primary production with extensive on-site and regional tree ring observations. We found widespread temporal decoupling between carbon assimilation and tree growth,...

Exotics are more complementary over time in tree biodiversity-ecosystem functioning experiments

Michael Belluau, Alain Paquette, Dominique Gravel, Peter Reich, Artur Stefanski & Christian Messier
Background and aims The Biodiversity – Ecosystem Functioning (BEF) literature proposes that ecosystem functioning increases with biodiversity because of complementarity in resource use among species, associated with functional diversity. In this study, we challenge the trait-based ecology framework by comparing congeneric exotic (European) and native (North American) tree species showing similar resource-use functional trait values. The trait-based framework suggests that two functionally equivalent species should play similar roles in a community, resulting in similar interactions...

Price-Level Targeting and Stabilization Policy: A Review

Steve Ambler
The author surveys recent articles on the costs and benefits of price-level targeting versus inflation targeting, focusing on the benefits and costs of price-level targeting as a tool for stabilization policy. He reviews papers that examine how price-level targeting affects the short-run trade-off between output and inflation variability by influencing expectations of future inflation. The author looks at the implications of this argument for assigning an objective based on price-level targeting to a central bank...

Technology Shocks and Business Cycles: The Role of Processing Stages and Nominal Rigidities

Louis Phaneuf & Nooman Rebei
This paper develops and estimates a dynamic general equilibrium model that realistically accounts for an input-output linkage between firms operating at different stages of processing. Firms face technological change which is specific to their processing stage and charge new prices according to stage-specific Calvo-probabilities. Only a fixed fraction of households have an opportunity to adjust nominal wages to new information each period. Intermediate-stage technology shocks account for the bulk of output variability at business cycle...

Astronomical climate forcing of ~2.5 Ga banded iron formations

Margriet L. Lantink, Joshua H. F. L. Davies, Rick Hennekam, Frederik J. Hilgen, David McB. Martin, Paul R. D. Mason, Gert-Jan Reichart & Urs Schaltegger
Utrecht University, The Netherlands (1); Université du Québec à Montréal, Canada (2); University of Geneva, Switzerland (3); Royal Netherlands Institute for Sea Research, and Utrecht University, The Netherlands (4; Geological Survey of Western Australia (5)

Large-scale banded iron formations (BIFs) were deposited during Neoarchean to early Paleoproterozoic and have been mainly linked to hydrothermal plume activity and the rise of oxygen in the ocean and atmosphere. However, the potential influence of astronomical “Milankovitch”...

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  • University of Quebec at Montreal
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  • Université Laval
  • Université du Québec en Outaouais
  • University of Minnesota
  • Concordia University
  • Bank of Canada
  • Université du Québec en Abitibi-Témiscamingue
  • University of Montpellier