Search results for "Vertebra"
showing 10 items of 1220 documents
Role of post mortem computed tomography in diagnosis of upper cervical fractures in child due to road accident: A case report and literature review
2019
The upper cervical spine has unique anatomical features that distinguish it from the remainder of the cervical spine. Its motion segments make up a large amount of total cervical spine motion and, as a result,predispose it to a unique set of injuries. Cervical spine trauma is a common problem with a wide range of severity from minor ligamentous injury to section of the spinal cord. The use of post mortem CT (PMCT), and the subsequent multi-planar and volume rendering reconstruction techniques can provide non-invasive, objective operator-independent imaging data set that may be further reviewed by other specialists. and can substantially add to forensic examinations of the skeleton, especial…
Transparency reduces predator detection in mimetic clearwing butterflies
2019
International audience; Predation is an important selective pressure and some prey have evolved conspicuous warning signals that advertise unpalatability (i.e. aposematism) as an antipredator defence. Conspicuous colour patterns have been shown effective as warning signals, by promoting predator learning and memory. Unexpectedly, some butterfly species from the unpalatable tribe Ithomiini possess transparent wings, a feature rare on land but common in water, known to reduce predator detection.We tested if transparency of butterfly wings was associated with decreased detectability by predators, by comparing four butterfly species exhibiting different degrees of transparency, ranging from ful…
Weak warning signals can persist in the absence of gene flow
2019
Aposematic organisms couple conspicuous warning signals with a secondary defense to deter predators from attacking. Novel signals of aposematic prey are expected to be selected against due to positive frequency-dependent selection. How, then, can novel phenotypes persist after they arise, and why do so many aposematic species exhibit intrapopulation signal variability? Using a polytypic poison frog (Dendrobates tinctorius), we explored the forces of selection on variable aposematic signals using 2 phenotypically distinct (white, yellow) populations. Contrary to expectations, local phenotype was not always better protected compared to novel phenotypes in either population; in the white popul…
Author Correction: Evaluation of three methods for biomass estimation in small invertebrates, using three large disparate parasite species as model o…
2018
Invertebrate biomass is considered one of the main factors driving processes in ecosystems. It can be measured directly, primarily by weighing individuals, but more often indirect estimators are used. We developed two indirect and non-destructive approaches to estimate biomass of small invertebrates in a simple manner. The first one was based on clay modelling and the second one was based on image analysis implemented with open-source software. Furthermore, we tested the accuracy of the widely used geometric approximation method (third method). We applied these three different methods to three morphologically disparate model species, an acanthocephalan worm, a crustacean and a flatworm. To …
Chondrichthyans from the Spanish Triassic (westernmost Tethys) with remarks on the evolution of enameloid
2020
The Triassic sediments of the Iberian Peninsula has been the focus of Geological and Paleontological studies for more than a century and the stratigraphic sequence and the invertebrate assemblages are well established for a number of different basin. However, works focused on chondrichthyans faunas were nonexistent until recently. As a consequence, it has been long time assumed that chondrichthyans were very scarce (or inexistent) in the coastal environments of the current Iberian Peninsula during Triassic times. This view changed at the beginning of the last decade, with the studies of paleontologist from the department of Geology of the University of Valencia (Dra. Márquez-Aliaga, Dr. Héc…
Environmental drivers of lake profundal macroinvertebrate community variation : implications for bioassessment
2011
Assessing the conservation priority of freshwater lake sites based on taxonomic, functional and environmental uniqueness
2022
Aim We propose a novel approach that considers taxonomic uniqueness, functional uniqueness and environmental uniqueness and show how it can be used in guiding conservation planning. We illustrate the approach using data for lake biota and environment. Location Lake Puruvesi, Finland. Methods We sampled macrophytes and macroinvertebrates from the same 18 littoral sites. By adapting the original “ecological uniqueness” approach, we used distance-based methods to calculate measures of taxonomic (LCBD–t), functional (LCBD–f) and environmental (LCEH) uniqueness for each site. We also considered the numbers and locations of the sites needed to protect up to 70% of total variation in taxonomic, fu…
Visual Contrast Modulates Operant Learning Responses in Larval Zebrafish.
2018
The larval zebrafish is a promising vertebrate model organism to study neural mechanisms underlying learning and memory due to its small brain and rich behavioral repertoire. Here, we report on a high-throughput operant conditioning system for zebrafish larvae, which can simultaneously train 12 fish to associate a visual conditioned pattern with electroshocks. We find that the learning responses can be enhanced by the visual contrast, not the spatial features of the conditioned patterns, highlighted by several behavioral metrics. By further characterizing the learning curves as well as memory extinction, we demonstrate that the percentage of learners and the memory length increase as the co…
Zoologia. Cordati invertebrati
2017
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« Mais qui êtes-vous donc, Monsieur Charles Nodier ? »
2020
Biographical note addressing all aspects of the intellectual and artistic life of Charles Nodier (1780-1844), the reasons for his exclusion from the Pantheon of French Letters from his death until the second half of the 20th century and the most recent signs of its gradual rebirth.