Search results for "Systematics"
showing 10 items of 6702 documents
The Hierarchical Agglomerative Clustering with Gower index: a methodology for automatic design of OLAP cube in ecological data processing context
2015
In Press, Corrected Proof; International audience; The OLAP systems can be an improvement for ecological studies. In fact, ecology studies, follows and analyzes phenomenon across space and time and according to several parameters. OLAP systems can provide to ecologists browsing in a large dataset. One focus of the current research on OLAP system is the automatic design of OLAP cubes and of data warehouse schemas. This kind of works makes accessible OLAP technology to non information technology experts. But to be efficient, the automatic OLAP building must take into account various cases. Moreover the OLAP technology is based on the concept of hierarchy. Thereby the hierarchical clustering m…
Speed-accuracy trade-off and its consequences in a scramble competition context.
2014
Abstract: Animals foraging in groups commonly respond to the presence of others by increasing their foraging rate, an increase that could come at the expense of prey detection accuracy. Yet the existence and consequences of such so-called 'speed-accuracy trade-offs' in group-foraging animals remain unexplored. We used group-feeding zebra finches, Taeniopygia guttata, to determine how search speed affects food detection accuracy and how a potential speed-accuracy trade-off influences feeding success. We found significant between-individual differences in hopping speed as well as evidence that faster individuals were more likely to overlook food, demonstrating the existence of a trade-off bet…
Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes
2018
This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural particulate organic carbon (POC) downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment trap data, and its effects on sediment bioirrigation capacity and organic matter (OM) degradation pathways were investigated constraining an early diagenesis model by using original data collected in sediment porewater. The measurements were performed at stations located inside and outside the ar…
Distribution and ecology of the Globigerinoides ruber — Globigerinoides elongatus morphotypes in the Azores region during the late Pleistocene-Holoce…
2018
Abstract Globigerinoides ruber is the dominant taxon in the North Atlantic Subtropical Gyre, nowadays limited to the north by the Azores Current. It is highly sensitive to recent and late Pleistocene Azores Front Current System variability. In this study, we analyse the distribution of five individual morphotypes of the G. ruber – G. elongatus plexus (G. ruber s.s., G. ruber cyclostoma type, G. elongatus, G. elongatus cf.1, G. elongatus pyramidical type) and G. ruber kummerform gr. in a core (ATA13-OF-KT1) collected southwest of the Azores islands and located in a strategical position near the present-day boundary of the Subtropical Gyre/Azores Front Current System (STG/AFCS). Micropaleonto…
Covarying shell growth parameters and the regulation of shell shape in marine bivalves: a case study on Tellinoidea.
2014
Specific parameters characterising shell shape may arguably have a significant role in the adaptation of bivalve molluscs to their particular environments. Yet, suchfunctionally relevantshape parameters (shell outline elongation, dissymmetry, and ventral convexity) are not those parameters that the animal may directly control. Rather than shell shape, the animal regulates shell growth. Accordingly, an alternative,growth-baseddescription of shell-shape is best fitted to understand how the animal may control the achieved shell shape. The key point is, in practice, to bring out the link between those two alternative modes of shell-shape descriptions, that is, to derive the set of equations whi…
Fossil echinoid (Echinoidea, Echinodermata) diversity of the Early Cretaceous (Hauterivian) in the Paris Basin (France).
2013
11 pages; International audience; This dataset inventories occurrence records of fossil echinoid specimens collected in the Calcaires à Spatangues Formation (CSF) that crops out in the southeast of the Paris Basin (France), and is dated from the Acanthodiscus radiatus chronozone (ca. 132 Ma, early Hauterivian, Early Cretaceous). Fossil richness and abundance of the CSF has attracted the attention of palaeontologists since the middle of the nineteenth century. This dataset compiles occurrence data (referenced by locality names and geographic coordinates with decimal numbers) of fossil echinoids both collated from the literature published over a century and a half, and completed by data from …
Présence de la musaraigne de Miller Neomys anomalus Cabrera, 1907 (Soricomorpha, Soricidae) dans l'Isle Crémieu (Isère, France).
2012
Presence of Miller's water shrew Neomys anomalus Cabrera, 1907 (Soricomorpha, Soricidae) in Isle Crémieu (Isère, France). - This note reports and comments on the presence of Miller's water shrew Neomys anomalus Cabrera, 1907 in Isle Crémieu (Isère, France).
Nouvelles données sur la localité type et la morphométrie dentaire du campagnol de Gerbe Microtus pyrenaicus gerbei (Gerbe, 1879) (Cricetidae, Rodent…
2015
New data on type locality and dental morphometry of the Gerbe’s vole Microtus pyrenaicus gerbei (Gerbe, 1879) (Cricetidae, Rodentia). The synthesis of the historical research done on Arthur de L’Isle du Dréneuf’s life, the discoverer of the Gerbe’s vole Microtus pyrenaicus gerbei (Gerbe, 1879), and the circumstances connected with this discovery, allow to say that its type locality is the municipality of La Haie-Fouassière (Loire-Atlantique, France). The analysis of teeth found in pellets of barn owl from Pornic (Loire-Atlantique, France) has confirmed the odontometrical differentiation previously observed in M. pyrenaicus gerbei.
A propos de l'observation de cas de campagnols des champs Microtus arvalis (Pallas, 1778) (Rodentia, Arvicolinae) caractérisés par une première molai…
2008
About some cases of common voles Microtus arvalis (Pallas, 1778) (Rodentia, Arvicolinae) characterised by a first lower molar with a pitymyan rhombus. This note describes and comments on some cases of common voles Microtus arvalis (Pallas, 1778) characterised by a first lower molar with a pitymyan rhombus.
Biological Flora of the British Isles: Ambrosia artemisiifolia
2015
This account presents information on all aspects of the biology of Ambrosia artemisiifolia L. (Common ragweed) that are relevant to understanding its ecology. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, and history, conservation, impacts and management. Ambrosia artemisiifolia is a monoecious, wind-pollinated, annual herb native to North America whose height varies from 10 cm to 2.5 m, according to environmental conditions. It has erect, branched stems …