The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
M. Muller - One of the best experts on this subject based on the ideXlab platform.
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Size limitations in semicircular duct systems
Journal of Theoretical Biology, 1999Co-Authors: M. MullerAbstract:Abstract The present article discusses mechanical requirements and limitations which are applicable to the construction of the system of semicircular ducts, especially to its size. The simplified case of a single, uniform duct system has been considered which can be described by a second order equation of motion. The principal functional quantities for this rotation-sensor are: (1) response speed; (2) sensitivity; and (3) regular flow. The response speed of a single, uniform semicircular duct is characterized by the short time constant (T2) which is dependent on the duct radius (r). Its estimated range is from 0.04 ms in the smallest to 140 ms in the largest known Labyrinth. The sensitivity is characterized by the maximal endolymph displacement after a step stimulus (xmax). Its estimated range is from 0.0016 μm to 5.97 mm (6.56 decades!), assuming an input angular velocity of ω=1 rad s−1. The Reynolds number is a measure for an undisturbed laminar flow. Its estimated range varies from 7.38·10−4to 45.1 for ω=1 rad s−1. The above data follow from graphs in which, for a single uniform duct, circuit radius (R) is plotted against duct radius (r) for Labyrinths of 233 species belonging to different vertebrate-groups. A relation R =38.9·r1.60was determined. The smallest Labyrinth was found in a carp larva (Cyprinus), the largest in a whale shark (Rhincodon). Large whales possess Labyrinths of average mammalian size. It is revealed that semicircular duct size is bound by requirements concerning regular flow and by a too low response speed for large Labyrinths, and by a too low sensitivity for small Labyrinths. Other important quantities are mechanical amplification factors which are a consequence of more complex vestibular constructions than a single uniform duct circuit. Allometric relationships are interpreted as compromises between the quantities mentioned. A hypothesis for the relatively large semicircular duct sizes of fishes, especially Elasmobranchii , compared with mammals and birds is presented.
Nathalie Wery - One of the best experts on this subject based on the ideXlab platform.
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Effects of the chlorination and pressure flushing of drippers fed by reclaimed wastewater on biofouling
Science of the Total Environment, 2021Co-Authors: Kevin Lequette, Nassim Ait-mouheb, Nicolas Adam, Marine Muffat-jeandet, Valérie Bru-adan, Nathalie WeryAbstract:Milli-channel baffle Labyrinths are widely used in drip irrigation systems. They induce a pressure drop enabling drip irrigation. However, with a section thickness that is measured in mm2, they are sensitive to clogging, which reduces the performance and service life of a drip irrigation system. The impact of chlorination (1.5 ppm of free chlorine during 1 h application) and pressure flushing (0.18 MPa) on the biofouling of non-pressure-compensating drippers, fed by real reclaimed wastewater, was studied at lab scale using optical coherence tomography. The effect of these treatments on microbial composition (bacteria and eukaryotes) was also investigated by High-throughput DNA sequencing. Biofouling was mainly observed in the inlet, outlet and return areas of the milli-Labyrinth channel from drippers. Chlorination reduced biofilm development, particularly in the mainstream of the milli-Labyrinth channel, and it was more efficient when combined with pressure flushing. Moreover, chlorination was more efficient in maintaining water distribution uniformity (CU < 95% compared to less than 85% for unchlorinated lines). It reduced more efficiently the bacterial concentration (≈1 log) and the diversity of the bacterial community in the dripper biofilms compared to the pressure flushing method. Chlorination significantly modified the microbial communities, promoting chlorine-resistant bacteria such as Comamonadaceae or Azospira. Inversely, several bacterial groups were identified as sensitive to chlorination such as Chloroflexi and Planctomycetes. Nevertheless, one month after stopping the treatments bacterial diversity recovered and the chlorine-sensitive bacteria such as Chloroflexi phylum and the Saprospiraceae, Spirochaetaceae, Christensenellaceae and Hydrogenophilaceae families re-emerged in conjunction with the growth of biofouling, highlighting the resilience of the bacteria originating from drippers. Based on PCoA analyses, the structure of the bacterial communities still clustered separately from non-chlorinated drippers, showing that the effect of chlorination was still detectable one month after stopping the treatment.
John J. Flynn - One of the best experts on this subject based on the ideXlab platform.
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comparative anatomy of the bony Labyrinth of extant and extinct porpoises cetacea phocoenidae
Biological Journal of The Linnean Society, 2016Co-Authors: William Gearty, Naoki Kohno, Rachel A Racicot, John J. FlynnAbstract:The inner ear anatomy of cetaceans, now more readily accessible by means of nondestructive high-resolution X-ray computed tomographic (CT) scanning, provides a window into their acoustic abilities and ecological preferences. Inner ear Labyrinths also may be a source for additional morphological characters for phylogenetic analyses. In this study, we explore digital endocasts of the inner ear Labyrinths of representative species of extinct and extant porpoises (Mammalia: Cetacea: Phocoenidae), a clade of some of the smallest odontocete cetaceans, which produce some of the highest-frequency clicks for biosonar and communication. Metrics used to infer hearing ranges based on cochlear morphology indicate that all taxa considered could hear high-frequency sounds, thus the group had already acquired high-frequency hearing capabilities by the Miocene (9–11 Mya) at the latest. Vestibular morphology indicates that extant species with pelagic preferences have similarly low semicircular canal deviations from 90°, values indicating more sensitivity to head rotations. Species with near-shore preferences have higher canal deviation values, indicating less sensitivity to head rotations. Extending these analyses to the extinct species, we demonstrate a good match between those predicted to have coastal (such as Semirostrum cerutti) preferences and high canal deviation values. We establish new body length relationships based on correlations with inner ear Labyrinth volume, which can be further explored among other aquatic mammals to infer body size of specimens consisting of fragmentary material.
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bony Labyrinth shape variation in extant carnivora a case study of musteloidea
Journal of Anatomy, 2016Co-Authors: Jack Z Tseng, Renaud Lebrun, Renaud Boistel, Camille Grohé, John J. FlynnAbstract:: The bony Labyrinth provides a proxy for the morphology of the inner ear, a primary cognitive organ involved in hearing, body perception in space, and balance in vertebrates. Bony Labyrinth shape variations often are attributed to phylogenetic and ecological factors. Here we use three-dimensional (3D) geometric morphometrics to examine the phylogenetic and ecological patterns of variation in the bony Labyrinth morphology of the most species-rich and ecologically diversified traditionally recognized superfamily of Carnivora, the Musteloidea (e.g. weasels, otters, badgers, red panda, skunks, raccoons, coatis). We scanned the basicrania of specimens belonging to 31 species using high-resolution X-ray computed micro-tomography (μCT) to virtually reconstruct 3D models of the bony Labyrinths. Labyrinth morphology is captured by a set of six fixed landmarks on the vestibular and cochlear systems, and 120 sliding semilandmarks, slid at the center of the semicircular canals and the cochlea. We found that the morphology of this sensory structure is not significantly influenced by bony Labyrinth size, in comparisons across all musteloids or in any of the individual traditionally recognized families (Mephitidae, Procyonidae, Mustelidae). PCA (principal components analysis) of shape data revealed that bony Labyrinth morphology is clearly distinguishable between musteloid families, and permutation tests of the Kmult statistic confirmed that the bony Labyrinth shows a phylogenetic signal in musteloids and in most mustelids. Both the vestibular and cochlear regions display morphological differences among the musteloids sampled, associated with the size and curvature of the semicircular canals, angles between canals, presence or absence of a secondary common crus, degree of lateral compression of the vestibule, orientation of the cochlea relative to the semicircular canals, proportions of the cochlea, and degree of curvature of its turns. We detected a significant ecological signal in the bony Labyrinth shape of musteloids, differentiating semi-aquatic taxa from non-aquatic ones (the taxa assigned to terrestrial, arboreal, semi-arboreal, and semi-fossorial categories), and a significant signal for mustelids, differentiating the bony Labyrinths of terrestrial, semi-arboreal, arboreal, semi-fossorial and semi-aquatic species from each other. Otters and minks are distinguished from non-aquatic musteloids by an oval rather than circular anterior canal, sinuous rather than straight lateral canal, and acute rather than straight angle between the posterior and lateral semicircular canals - each of these morphological characters has been related previously to animal sensitivity for detecting head motion in space.
Loïc Costeur - One of the best experts on this subject based on the ideXlab platform.
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shape variation and ontogeny of the ruminant bony Labyrinth an example in tragulidae
Journal of Anatomy, 2016Co-Authors: Bastien Mennecart, Loïc CosteurAbstract:Despite its growing use in anatomical and ecological studies, the morphological variability and ontogenetic development of the bony Labyrinth have very rarely been investigated in ruminants. Here we study its morphology in 15 adult and 10 juvenile specimens in the three extant tragulid ruminant genera. Intraspecific and interspecific variability is quantified using morphometric and 3D geometric morphometrics analyses. The bony Labyrinth of Tragulus, Hyemoschus, and Moschiola is strikingly different, clustering in clearly different morphospaces despite similar ecological adaptations. Although the bony Labyrinths within two species of the same genus cannot be distinguished from each other based on the chosen semi-landmarks, discrete interspecific differences exist. We were able to show for the first time that an artiodactyl mammal in a late fetal stage possesses an almost fully formed bony Labyrinth similar to that of adults. No significant change either occurs in size or morphology after ossification of the petrosal bone. Some intraspecific variation is observed on the shape of the lateral semi-circular canal, the size and shape of the common crus, the coil of the cochlea or the stapedial ratio. Variable structures are expected to be highly informative characters for a large cladistic analysis. They can be used for phylogenetic studies in ruminants. Incorporating juvenile specimens in studies is not problematic, as they fall within the morphological range of adults.
Camille Grohé - One of the best experts on this subject based on the ideXlab platform.
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bony Labyrinth shape variation in extant carnivora a case study of musteloidea
Journal of Anatomy, 2016Co-Authors: Jack Z Tseng, Renaud Lebrun, Renaud Boistel, Camille Grohé, John J. FlynnAbstract:: The bony Labyrinth provides a proxy for the morphology of the inner ear, a primary cognitive organ involved in hearing, body perception in space, and balance in vertebrates. Bony Labyrinth shape variations often are attributed to phylogenetic and ecological factors. Here we use three-dimensional (3D) geometric morphometrics to examine the phylogenetic and ecological patterns of variation in the bony Labyrinth morphology of the most species-rich and ecologically diversified traditionally recognized superfamily of Carnivora, the Musteloidea (e.g. weasels, otters, badgers, red panda, skunks, raccoons, coatis). We scanned the basicrania of specimens belonging to 31 species using high-resolution X-ray computed micro-tomography (μCT) to virtually reconstruct 3D models of the bony Labyrinths. Labyrinth morphology is captured by a set of six fixed landmarks on the vestibular and cochlear systems, and 120 sliding semilandmarks, slid at the center of the semicircular canals and the cochlea. We found that the morphology of this sensory structure is not significantly influenced by bony Labyrinth size, in comparisons across all musteloids or in any of the individual traditionally recognized families (Mephitidae, Procyonidae, Mustelidae). PCA (principal components analysis) of shape data revealed that bony Labyrinth morphology is clearly distinguishable between musteloid families, and permutation tests of the Kmult statistic confirmed that the bony Labyrinth shows a phylogenetic signal in musteloids and in most mustelids. Both the vestibular and cochlear regions display morphological differences among the musteloids sampled, associated with the size and curvature of the semicircular canals, angles between canals, presence or absence of a secondary common crus, degree of lateral compression of the vestibule, orientation of the cochlea relative to the semicircular canals, proportions of the cochlea, and degree of curvature of its turns. We detected a significant ecological signal in the bony Labyrinth shape of musteloids, differentiating semi-aquatic taxa from non-aquatic ones (the taxa assigned to terrestrial, arboreal, semi-arboreal, and semi-fossorial categories), and a significant signal for mustelids, differentiating the bony Labyrinths of terrestrial, semi-arboreal, arboreal, semi-fossorial and semi-aquatic species from each other. Otters and minks are distinguished from non-aquatic musteloids by an oval rather than circular anterior canal, sinuous rather than straight lateral canal, and acute rather than straight angle between the posterior and lateral semicircular canals - each of these morphological characters has been related previously to animal sensitivity for detecting head motion in space.
