Search results for "constraints"

Covariation and phenotypic integration in chemical communication displays: biosynthetic constraints and eco-evolutionary implications

2018

Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta‐analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated t…

Phylogeography and Molecular Evolution of Potato virus Y

2012

Potato virus Y (PVY) is an important plant pathogen, whose host range includes economically important crops such as potato, tobacco, tomato, and pepper. PVY presents three main strains (PVYO, PVYN and PVYC) and several recombinant forms. PVY has a worldwide distribution, yet the mechanisms that promote and maintain its population structure and genetic diversity are still unclear. In this study, we used a pool of 77 complete PVY genomes from isolates collected worldwide. After removing the effect of recombination in our data set, we used Bayesian techniques to study the influence of geography and host species in both PVY population structure and dynamics. We have also performed selection and…

Developing common protocols to measure tundra herbivory across spatial scales

2021

Understanding and predicting large-scale ecological responses to global environmental change requires comparative studies across geographic scales with coordinated efforts and standardized methodologies. We designed, applied and assessed standardized protocols to measure tundra herbivory at three spatial scales: plot, site (habitat), and study area (landscape). The plot and site-level protocols were tested in the field during summers 2014-2015 at eleven sites, nine of them comprising warming experimental plots included in the International Tundra Experiment (ITEX). The study area protocols were assessed during 2014-2018 at 24 study areas across the Arctic. Our protocols provide comparable a…

Interrogating witnesses for geometric constraint solving

2012

International audience; Classically, geometric constraint solvers use graph-based methods to decompose systems of geometric constraints. These methods have intrinsic limitations, which the witness method overcomes; a witness is a solution of a variant of the system. This paper details the computation of a basis of the vector space of free infinitesimal motions of a typical witness, and explains how to use this basis to interrogate the witness for dependence detection. The paper shows that the witness method detects all kinds of dependences: structural dependences already detectable by graph-based methods, but also non-structural dependences, due to known or unknown geometric theorems, which…

Mass, phylogeny, and temperature are sufficient to explain differences in metabolic scaling across mammalian orders?

2016

Abstract Whether basal metabolic rate‐body mass scaling relationships have a single exponent is highly discussed, and also the correct statistical model to establish relationships. Here, we aimed (1) to identify statistically best scaling models for 17 mammalian orders, Marsupialia, Eutheria and all mammals, and (2) thereby to prove whether correcting for differences in species’ body temperature and their shared evolutionary history improves models and their biological interpretability. We used the large dataset from Sieg et al. (The American Naturalist 174, 2009, 720) providing species’ body mass (BM), basal metabolic rate (BMR) and body temperature (T). We applied different statistical ap…

The directed profitable rural postman problem with incompatibility constraints

2017

[EN] In this paper, we study a variant of the directed rural postman problem (RPP) where profits are asso- ciated with arcs to be served, and incompatibility constraints may exist between nodes and profitable arcs leaving them. If convenient, some of the incompatibilities can be removed provided that penalties are paid. The problem looks for a tour starting and ending at the depot that maximizes the difference between collected profits and total cost as sum of traveling costs and paid penalties, while satisfying remaining incompatibilities. The problem finds application in the domain of road transportation service, and in particular in the context of horizontal collaboration among carriers …

Use of contrastive syllabic information in L1-L2map for Spanish pronunciation teaching

2018

En la adquisición del sistema fónico de una segunda lengua (L2) al aprendiz no le basta con familiarizarse con los nuevos sonidos nuevos de la L2, sino que debe interiorizar las pautas distribucionales de los segmentos y las restricciones silábicas propias de la L2. El objetivo de este trabajo es, por un lado, reflexionar sobre los factores lingüísticos y contrastivos que pueden influir en la adquisición de las restricciones silábicas del español como lengua extranjera y, por otro lado, presentar las nuevas funciones de la base de datos multilingüe L1-L2map que permiten, precisamente, realizar análisis contrastivos de la estructura silábica de una lengua nativa (L1) y una L2. A lo largo del…

2015

This paper provides a commentary on the academic literature on accounting conservatism with a view to highlighting the insights of that literature that are potentially useful for accounting standar...

Data from: Assessing metabolic constraints on the maximum body size of actinopterygians: locomotion energetics of Leedsichthys problematicus (Actinop…

2019

Maximum sizes attained by living actinopterygians are much smaller than those reached by chondrichthyans. Several factors, including the high metabolic requirements of bony fishes, have been proposed as possible body-size constraints but no empirical approaches exist. Remarkably, fossil evidence has rarely been considered despite some extinct actinopterygians reaching sizes comparable to those of the largest living sharks. Here, we have assessed the locomotion energetics of Leedsichthys problematicus, an extinct gigantic suspension-feeder and the largest actinopterygian ever known, shedding light on the metabolic limits of body size in actinopterygians and the possible underlying factors th…

Constraints representing a meta-stable régime facilitate exploration during practice and transfer of learning in a complex multi-articular task

2018

Previous investigations have shown that inducing meta-stability\ud in behavior can be achieved by overlapping affordances through constraint\ud manipulation, allowing cooperative and competitive tendencies to\ud functionally coexist. The purpose of this paper was to test a number of\ud conditions applying these design principles on performance during skills\ud practice and transfer. Of additional interest, was whether the existing\ud skill level interacted with the environmental properties of the\ud experimental tasks (varying indoor climbing routes). Two skill groups\ud practised on three routes per session over four separate sessions. At the\ud end of the final session, climbers undertook…