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result(s) for
"Payet, B"
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Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution
2013
The larger number of models of asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole asteroid population. With a larger statistical sample we can study the physical properties of asteroid populations, such as main-belt asteroids or individual asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of asteroids used in our previous paper. We present 119 new asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetics and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.
Population genomics informs the management of harvested snappers across north-western Australia
by
Saunders, Thor
,
Miller, Karen
,
Travers, Michael J.
in
631/158/1745
,
631/158/2039
,
631/158/2452
2024
Failure to consider population structure when managing harvested fishes increases the risk of stock depletion, yet empirical estimates of population structure are often lacking for important fishery species. In this study, we characterise genetic variation in single nucleotide polymorphisms (SNPs) to assess population structure for three harvested species of tropical snappers across the broad (up to 300 km wide) and extensive (~ 4000 km) continental shelf of north-western Australia. Comparisons across ~ 300 individuals per species, showed remarkably similar patterns of genetic structure among
Lutjanus sebae
(red emperor),
L. malabaricus
(saddletail snapper) and
Pristipomoides multidens
(goldband snapper) despite subtle differences in biological and ecological traits. Low levels of genetic subdivision were reflected in an isolation by distance relationship where genetic connectivity increased with geographic proximity. This indicates extensive but not unlimited dispersal across the north-western Australian shelf. Our findings provide evidence of connectivity between current management areas, violating the assumption of multiple independent stocks. Spatial stock assessment models may be more suitable for the management of these species however demographic connectivity rates cannot be accurately estimated from the conventional population genetic approaches applied in this study. We recommend that managers aim to maintain adequate spawning biomass across current management areas, and assess stocks at finer scales, where practical.
Journal Article
Description and phylogenetic placement of Beauveria hoplocheli sp. nov. used in the biological control of the sugarcane white grub, Hoplochelus marginalis, on Reunion Island
2015
On Reunion Island successful biological control of the sugarcane white grub Hoplochelus marginalis Fairmaire (Coleoptera: Melolonthidae) has been conducted for decades with strains from the entomopathogenic fungal genus Beauveria (Ascomycota: Hypocreales). A study based on morphological characters combined with a multisequence phylogenetic analysis of genes that encode the translation elongation factor 1-alpha (TEF1), RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2) and the Bloc nuc intergenic region was carried out on Beauveria strains isolated on Reunion and Madagascar from H. marginalis. This study revealed that these strains, previously identified as Beauveria brongniartii, did not match that species and are closely related to but still distinct from B. malawiensis strains. Therefore we describe the Reunion Island fungus as the new species B. hoplocheli.
Journal Article
Demographic histories shape population genomics of the common coral grouper (Plectropomus leopardus)
by
Berumen, Michael L.
,
DiBattista, Joseph D.
,
Payet, Samuel D.
in
Commercial fishing
,
Coral reefs
,
Demography
2022
Many coral reef fishes display remarkable genetic and phenotypic variation across their geographic ranges. Understanding how historical and contemporary processes have shaped these patterns remains a focal question in evolutionary biology since they reveal how diversity is generated and how it may respond to future environmental change. Here, we compare the population genomics and demographic histories of a commercially and ecologically important coral reef fish, the common coral grouper (Plectropomus leopardus [Lacépède 1802]), across two adjoining regions (the Great Barrier Reef; GBR, and the Coral Sea, Australia) spanning approximately 14 degrees of latitude and 9 degrees of longitude. We analysed 4548 single nucleotide polymorphism (SNP) markers across 11 sites and show that genetic connectivity between regions is low, despite their relative proximity (~100 km) and an absence of any obvious geographic barrier. Inferred demographic histories using 10,479 markers suggest that the Coral Sea population was founded by a small number of GBR individuals and that divergence occurred ~190 kya under a model of isolation with asymmetric migration. We detected population expansions in both regions, but estimates of contemporary effective population sizes were approximately 50% smaller in Coral Sea sites, which also had lower genetic diversity. Our results suggest that P. leopardus in the Coral Sea have experienced a long period of isolation that precedes the recent glacial period (~10–120 kya) and may be vulnerable to localized disturbances due to their relative reliance on local larval replenishment. While it is difficult to determine the underlying events that led to the divergence of the Coral Sea and GBR lineages, we show that even geographically proximate populations of a widely dispersed coral reef fish can have vastly different evolutionary histories.
Journal Article
Sympatric species of coral trout (Plectropomus) show contrasting patterns of genomic structure across isolated atoll reefs
by
DiBattista, Joseph D
,
Wakefield, Corey B
,
Payet, Samuel D
in
Atolls
,
Biological stocks
,
Commercial fishing
2024
Understanding patterns of connectivity across remote atoll reefs is important for managing fishery target species, as they often have small population sizes and limited options for replenishment in the event of localised decline. In this study, we used a comprehensive hierarchical sampling design combined with reduced representation genotyping to compare the population genomics of two sympatric species of coral trout (Plectropomus) within and between three isolated offshore atoll reef systems in north-western Australia. The blue spot coral trout, Plectropomus laevis (8979 single nucleotide polymorphisms—SNPs, 223 individuals, 25 sites) and the passionfruit coral trout, P. areolatus (3702 SNPs, 452 individuals, 20 sites) showed high levels of connectivity within reef systems and restricted connectivity between reef systems, indicating that biological stocks primarily occur at the scale of each reef system. Despite being closely related and co-managed species, inter-specific variation in the magnitude of genetic structure was notable. Plectropomus areolatus at the southern-most reef system display modest genetic structure with populations ~ 450 km to the north, whilst P. laevis at the same location show a level of genetic divergence that reflects deep historical isolation. Our results provide the most comprehensive assessment of genetic connectivity across these remote atoll reefs, facilitating management advice that reflect empirically determined population dynamics for these species. We identify contrasting patterns of genetic connectivity among closely related sympatric species, and highlight the role of extrinsic (e.g., geography/environment) and intrinsic (e.g., life history) factors in shaping population dynamics.
Journal Article
Chromosome-level genome assembly of the spangled emperor, Lethrinus nebulosus (Forsskål 1775)
by
Doran, Adrianne
,
de Jong, Emma
,
Skepper, Craig L.
in
631/208/212
,
631/208/514/1948
,
631/208/728
2025
Spangled emperor,
Lethrinus nebulosus
(Forsskål 1775), is a tropical marine fish of economic and cultural importance throughout the Indo-West Pacific. It is one of the most targeted recreational fishes in the Gascoyne Coast Bioregion of Western Australia where it serves as an indicator species for recreational fishing. Here, we present a highly accurate, near-gapless, chromosome-level, haplotype-phased reference genome assembly of
L. nebulosus
(
Lethrinus nebulosus
(Spangled Emperor) genome, fLetNeb1.1; PRJNA1074345), the first for the species and the first high-quality genome representative of the family Lethrinidae. The 1.09 Gb genome was assembled from PacBio HiFi and Dovetail Omni-C proximity ligation sequencing data. The contig N50 is 21–24 Mbp and BUSCO completeness greater than 99%. A preliminary gene annotation identified 24,583 genes with the predicted transcriptome achieving a BUSCO completeness score of 99.1% This resource will facilitate genomic studies to inform the sustainable management of
L. nebulosus
and other Lethrinids.
Journal Article
Prevalence and determinants of cognitive impairment in the euthymic phase of bipolar disorders: results from the FACE-BD cohort
2019
Cognitive deficits are a well-established feature of bipolar disorders (BD), even during periods of euthymia, but risk factors associated with cognitive deficits in euthymic BD are still poorly understood. We aimed to validate classification criteria for the identification of clinically significant cognitive impairment, based on psychometric properties, to estimate the prevalence of neuropsychological deficits in euthymic BD, and identify risk factors for cognitive deficits using a multivariate approach.
We investigated neuropsychological performance in 476 euthymic patients with BD recruited via the French network of BD expert centres. We used a battery of tests, assessing five domains of cognition. Five criteria for the identification of neuropsychological impairment were tested based on their convergent and concurrent validity. Uni- and multivariate logistic regressions between cognitive impairment and several clinical and demographic variables were performed to identify risk factors for neuropsychological impairment in BD.
One cut-off had satisfactory psychometric properties and yielded a prevalence of 12.4% for cognitive deficits in euthymic BD. Antipsychotics use were associated with the presence of a cognitive deficit.
This is the first study to validate a criterion for clinically significant cognitive impairment in BD. We report a lower prevalence of cognitive impairment than previous studies, which may have overestimated its prevalence. Patients with euthymic BD and cognitive impairment may benefit from cognitive remediation.
Journal Article
The second Sandia Fracture Challenge: predictions of ductile failure under quasi-static and moderate-rate dynamic loading
2016
Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the blind, quantitative predictive ability of simulation methods against a previously unseen failure problem. Rather than evaluate the predictions of a single simulation approach, the Sandia Fracture Challenge relies on numerous volunteer teams with expertise in computational mechanics to apply a broad range of computational methods, numerical algorithms, and constitutive models to the challenge. This exercise is intended to evaluate the state of health of technologies available for failure prediction. In the first Sandia Fracture Challenge, a wide range of issues were raised in ductile failure modeling, including a lack of consistency in failure models, the importance of shear calibration data, and difficulties in quantifying the uncertainty of prediction [see Boyce et al. (Int J Fract 186:5–68,
2014
) for details of these observations]. This second Sandia Fracture Challenge investigated the ductile rupture of a Ti–6Al–4V sheet under both quasi-static and modest-rate dynamic loading (failure in
∼
0.1 s). Like the previous challenge, the sheet had an unusual arrangement of notches and holes that added geometric complexity and fostered a competition between tensile- and shear-dominated failure modes. The teams were asked to predict the fracture path and quantitative far-field failure metrics such as the peak force and displacement to cause crack initiation. Fourteen teams contributed blind predictions, and the experimental outcomes were quantified in three independent test labs. Additional shortcomings were revealed in this second challenge such as inconsistency in the application of appropriate boundary conditions, need for a thermomechanical treatment of the heat generation in the dynamic loading condition, and further difficulties in model calibration based on limited real-world engineering data. As with the prior challenge, this work not only documents the ‘state-of-the-art’ in computational failure prediction of ductile tearing scenarios, but also provides a detailed dataset for non-blind assessment of alternative methods.
Journal Article
The melanocortin receptor subtypes in chicken have high preference to ACTH‐derived peptides
by
Johansson, Lisa
,
Gallo‐Payet, Nicole
,
Haitina, Tatjana
in
ACTH
,
Adrenocorticotropic Hormone - analogs & derivatives
,
Adrenocorticotropic Hormone - metabolism
2004
Melanocortin (MC) receptors are widely distributed throughout the body of chicken, like in mammals, and participate in a wide range of physiological functions. To clarify the pharmacological impact of ligands acting in the MC system, we expressed the chicken MC1, MC2, MC3, MC4 and MC5 (cMC1–5) receptors in eukaryotic cells and performed comprehensive pharmacological characterization of the potency of endogenous and synthetic melanocortin peptides. Remarkably, the cMC receptors displayed high affinity for ACTH‐derived peptides and in general low affinity for α‐MSH. It is evident that not only the cMC2 receptor but also the other cMC receptors interact with ACTH‐derived peptide through an epitope beyond the sequence of α‐MSH. The synthetic ligand MTII was found to be a potent agonist whereas HS024 was a potent antagonist at the cMC4 receptor, indicating that these ligands are suitable for physiological studies in chicken. We also show the presence of prohormone convertase 1 (PC1) and PC2 genes in chicken, and that these peptides are coexpressed with proopiomelanocortin (POMC) in various tissues. British Journal of Pharmacology (2004) 143, 626–637. doi:10.1038/sj.bjp.0705900
Journal Article