116 research outputs found
Investigation of LANDSAT D Thematic Mapper geometric performance: Line to line and band to band registration
The geometric accuray of LANDSAT TM raw data of Toulouse (France) raw data of Mississippi, and preprocessed data of Mississippi was examined using a CDC computer. Analog images were restituted on the VIZIR SEP device. The methods used for line to line and band to band registration are based on automatic correlation techniques and are widely used in automated image to image registration at CNES. Causes of intraband and interband misregistration are identified and statistics are given for both line to line and band to band misregistration
Investigating population dynamics from parentage analysis in the highly endangered fan mussel Pinna nobilis
Understanding dispersal patterns is a major focus for conservation biology as it influences
local survival and resilience in case of local disturbance, particularly for sessile
species. Dispersal can be assessed through parentage analyses by estimating family
structure and self-recruitment.
This study documents the family structure of a pelagic
spawner, Pinna nobilis, which is facing a major crisis that threatens its survival as most
of its populations have been decimated by a parasite, Haplosporidium pinnae. In this
context, we focused on a single population (Peyrefite, Banyuls-sur-
mer,
France) where
640 individuals were sampled in 2011, 2015, and 2018 and genotyped for 22 microsatellite
markers. Genetic diversity was high and homogeneous among years, with
mean allele numbers ranging between 13.6 and 14.8 and observed heterozygosities
(Ho) between 0.7121 and 0.7331. Low, but significant, genetic differentiations were
found between 2011–2015
and 2015–2018.
A parentage analysis described 11 clusters,
including one prevailing, and revealed that 46.9% of individuals were involved in
half-sib
relationships, even between years, suggesting that source populations were
recurrent year after year. There were few individuals resampled between years (30
in 2015 and 14 in 2018), indicating a rapid turnover. Considering the large number
of half-sib
relationships but the low number of relations per individual, we conclude
that P. nobilis exhibit homogeneous reproductive success. Self-recruitment
was not
detected, making this population highly vulnerable as replenishment only relies on
connectivity from neighboring populations. In the context of the pandemic caused by
H. pinnae, these results will have to be considered when choosing a location to reintroduce
individuals in potential future rescue plans.En prensa
Genetic homogeneity of the critically endangered fan mussel, Pinna nobilis, throughout lagoons of the Gulf of Lion (North‑Western Mediterranean Sea)
The fan mussel, Pinna nobilis, endemic to the Mediterranean Sea, is a critically endangered species
facing mass mortality events in almost all of its populations, following the introduction of the parasite
Haplosporidium pinnae. Such a unique pandemic in a marine organism, which spreads rapidly and
with mortality rates reaching up to 100%, could lead to the potential extinction of the species. Only
few regions, involving lagoon habitats, remain healthy throughout the entire Mediterranean Sea.
This study describes the genetic structure of P. nobilis across the Gulf of Lion, including confined
locations such as lagoons and ports. A total of 960 samples were collected among 16 sites distributed
at 8 localities, and then genotyped using 22 microsatellite markers. Genetic diversity was high in all
sites with mean allele numbers ranging between 10 and 14.6 and with observed heterozygosities (Ho)
between 0.679 and 0.704. No genetic differentiation could be identified (FST ranging from 0.0018 to
0.0159) and the percentages of related individuals were low and similar among locations (from 1.6 to
6.5%). Consequently, all fan mussels, over the entire coastline surveyed, including those in the most
geographically isolated areas, belong to a large genetically homogeneous population across the Gulf
of Lion. Considering the ongoing mass mortality context, this result demonstrates that almost all of
the genetic diversity of P. nobilis populations is still preserved even in isolated lagoons, which might
represent a refuge habitat for the future of the species.En prensa2,92
Global Diversity of Brittle Stars (Echinodermata: Ophiuroidea)
This review presents a comprehensive overview of the current status regarding the global diversity of the echinoderm class Ophiuroidea, focussing on taxonomy and distribution patterns, with brief introduction to their anatomy, biology, phylogeny, and palaeontological history. A glossary of terms is provided. Species names and taxonomic decisions have been extracted from the literature and compiled in The World Ophiuroidea Database, part of the World Register of Marine Species (WoRMS). Ophiuroidea, with 2064 known species, are the largest class of Echinodermata. A table presents 16 families with numbers of genera and species. The largest are Amphiuridae (467), Ophiuridae (344 species) and Ophiacanthidae (319 species). A biogeographic analysis for all world oceans and all accepted species was performed, based on published distribution records. Approximately similar numbers of species were recorded from the shelf (n = 1313) and bathyal depth strata (1297). The Indo-Pacific region had the highest species richness overall (825 species) and at all depths. Adjacent regions were also relatively species rich, including the North Pacific (398), South Pacific (355) and Indian (316) due to the presence of many Indo-Pacific species that partially extended into these regions. A secondary region of enhanced species richness was found in the West Atlantic (335). Regions of relatively low species richness include the Arctic (73 species), East Atlantic (118), South America (124) and Antarctic (126)
Environmental variables, habitat discontinuity and life history shaping the genetic structure of Pomatoschistus marmoratus
Coastal lagoons are semi-isolated ecosystems
exposed to wide fluctuations of environmental conditions
and showing habitat fragmentation. These features may
play an important role in separating species into different
populations, even at small spatial scales. In this study, we
evaluate the concordance between mitochondrial (previous
published data) and nuclear data analyzing the genetic
variability of Pomatoschistus marmoratus in five localities,
inside and outside the Mar Menor coastal lagoon (SE
Spain) using eight microsatellites. High genetic diversity
and similar levels of allele richness were observed across
all loci and localities, although significant genic and
genotypic differentiation was found between populations
inside and outside the lagoon. In contrast to the FST values
obtained from previous mitochondrial DNA analyses
(control region), the microsatellite data exhibited significant
differentiation among samples inside the Mar Menor
and between lagoonal and marine samples. This pattern
was corroborated using Cavalli-Sforza genetic distances.
The habitat fragmentation inside the coastal lagoon and
among lagoon and marine localities could be acting as a
barrier to gene flow and contributing to the observed
genetic structure. Our results from generalized additive
models point a significant link between extreme lagoonal
environmental conditions (mainly maximum salinity) and
P. marmoratus genetic composition. Thereby, these environmental
features could be also acting on genetic structure
of coastal lagoon populations of P. marmoratus favoring
their genetic divergence. The mating strategy of P. marmoratus
could be also influencing our results obtained from
mitochondrial and nuclear DNA. Therefore, a special
consideration must be done in the selection of the DNA
markers depending on the reproductive strategy of the
species
Tara Pacific Expedition\u27s atmospheric measurements of marine aerosols across the Atlantic and Pacific Oceans: Overview and preliminary results
Marine aerosols play a significant role in the global radiative budget, in clouds\u27 processes, and in the chemistry of the marine atmosphere. There is a critical need to better understand their production mechanisms, composition, chemical properties, and the contribution of ocean-derived biogenic matter to their mass and number concentration. Here we present an overview of a new dataset of in situ measurements of marine aerosols conducted over the 2.5-yr Tara Pacific Expedition over 110, 000 km across the Atlantic and Pacific Oceans. Preliminary results are presented here to describe the new dataset that will be built using this novel set of measurements. It will characterize marine aerosols properties in detail and will open a new window to study the marine aerosol link to the water properties and environmental conditions
Serum Apolipoproteins C-I and C-III Are Reduced in Stomach Cancer Patients: Results from MALDI-Based Peptidome and Immuno-Based Clinical Assays
Finding new peptide biomarkers for stomach cancer in human sera that can be implemented into a clinically practicable prediction method for monitoring of stomach cancer. We studied the serum peptidome from two different biorepositories. We first employed a C8-reverse phase liquid chromatography approach for sample purification, followed by mass-spectrometry analysis. These were applied onto serum samples from cancer-free controls and stomach cancer patients at various clinical stages. We then created a bioinformatics analysis pipeline and identified peptide signature discriminating stomach adenocarcinoma patients from cancer-free controls. Matrix Assisted Laser Desorption/Ionization–Time of Flight (MALDI-TOF) results from 103 samples revealed 9 signature peptides; with prediction accuracy of 89% in the training set and 88% in the validation set. Three of the discriminating peptides discovered were fragments of Apolipoproteins C-I and C-III (apoC-I and C-III); we further quantified their serum levels, as well as CA19-9 and CRP, employing quantitative commercial-clinical assays in 142 samples. ApoC-I and apoC-III quantitative results correlated with the MS results. We then employed apoB-100-normalized apoC-I and apoC-III, CA19-9 and CRP levels to generate rules set for stomach cancer prediction. For training, we used sera from one repository, and for validation, we used sera from the second repository. Prediction accuracies of 88.4% and 74.4% were obtained in the training and validation sets, respectively. Serum levels of apoC-I and apoC-III combined with other clinical parameters can serve as a basis for the formulation of a diagnostic score for stomach cancer patients
Famille, Territoire et Croissance : Système de valeurs du management familial en pme
International audienc
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