Maternal outcomes and risk factors for COVID-19 severity among pregnant women.

Pregnant women may be at higher risk of severe complications associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may lead to obstetrical complications. We performed a case control study comparing pregnant women with severe coronavirus disease 19 (cases) to pregnant women with a milder form (controls) enrolled in the COVI-Preg international registry cohort between March 24 and July 26, 2020. Risk factors for severity, obstetrical and immediate neonatal outcomes were assessed. A total of 926 pregnant women with a positive test for SARS-CoV-2 were included, among which 92 (9.9%) presented with severe COVID-19 disease. Risk factors for severe maternal outcomes were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. Pregnant women with severe maternal outcomes were at higher risk of caesarean section [70.7% (n = 53/75)], preterm delivery [62.7% (n = 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n = 31/75)]. In this study, several risk factors for developing severe complications of SARS-CoV-2 infection among pregnant women were identified including pulmonary comorbidities, hypertensive disorders and diabetes. Obstetrical and neonatal outcomes appear to be influenced by the severity of maternal disease

Ecological and genetical aspects of natural hybridization in Rhinanthus L

The general framework of this work is the study of natural hybridization between two Rhinanthus species (Orobanchaceae), Rhinanthus minor L. and Rhinanthus angustifolius Gmelin. Rhinanthus is a genus of annual hemi-parasitic plants in which many cases of interspecific crosses have been documented. In order to contribute to the understanding of hybrid formation, ecological requirements and mating system characteristics of both parental species were investigated. Moreover, patterns and dynamics of hybrid populations were studied. Different molecular markers such as microsatellite loci, species-specific ISSR and RAPD markers and chloroplast haplotypes were developed in order to study mating system, gene flow and hybridization. Performances of both parental species were tested in different hydric conditions. R. angustifolius was either as fit or fitter than R. minor in all conditions and for all studied fitness parameters. This advantage of R. angustifolius can be attributed to its larger size. The response to hydric conditions varied according to both the developmental stage of the plants and to the species, with a slight advantage of R. angustifolius in wet conditions. In pure populations, both species have a mixed mating system, but R. angustifolius was predominantly outcrossing (tm = 0.762), whereas R. minor was mostly selfing (tm = 0.134). In a mixed population, both parental species produced hybrid seeds, but at slightly different frequencies (5.9% on R. minor against 3.3% on R. angustifolius). Furthermore, artificial crosses showed that hybrid seed production is lower when formed on R. angustifolius than in R. minor, and hybrid seeds with R. minor as maternal parent have a much higher germination rate. In natural populations, first-generation hybrids are thus expected to be mainly produced by R. minor. Hybridization patterns showed that F1 hybrids were rapidly formed, and that asymmetrical bidirectional introgression with generally more introgressants close to R. angustifolius appeared in well-established populations. Spatial patterns revealed large fluctuations in the frequencies and/or in the spatial distribution of the alleles from year to year, which can be explained by the strong sensitivity of the mixed populations to environmental conditions. The fate of hybrid populations is difficult to predict or model, because the annual life cycle of the plants and the lack of persistent seed bank make them more vulnerable to environmental change. / Le cadre général de ce travail est l'étude de l'hybridation naturelle entre deux espèces de Rhinanthes (Orobanchaceae), Rhinanthus minor L. et Rhinanthus angustifolius Gmelin. Rhinanthus est un genre de plantes annuelles hémiparasites dans lequel de nombreux cas de croisements interspécifiques ont été décrits. Afin de mieux comprendre la formation des hybrides, les exigences écologiques et les caractéristiques du système reproducteur des deux espèces parentales ont été étudiées, de même que les patterns et l'évolution des populations hybrides. Différents marqueurs moléculaires tels que des microsatellites, des marqueurs RAPDs et ISSRs spécifiques à chaque espèce, et des marqueurs chloroplastiques ont été mis au point afin d'étudier les systèmes reproducteurs, les flux de gènes, et l'hybridation. Les performances des deux espèces parentales ont été testées sous différentes conditions d'humidité. R. angustifolius était soit aussi performant, soit plus performant que R. minor dans toutes les conditions et pour tous les paramètres de fitness étudiés. Cet avantage de R. angustifolius peut être attribué à sa plus grande taille. La réponse aux conditions hydriques variait selon le stade de développement des plantes et l'espèce, avec un léger avantage de R. angustifolius dans les conditions plus humides. Dans des populations pures, les deux espèces parentales présentaient un système reproducteur mixte, mais R. angustifolius était principalement allogame (tm = 0.762), alors que R. minor était principalement autogame (tm = 0.134). Dans une population mixte, les deux espèces parentales ont produit des graines hybrides, mais à des fréquences légèrement différentes (5.9% sur R. minor contre 3.3% sur R. angustifolius). De plus, des croisements artificiels ont montré que la production de graines hybrides est plus faible sur R. angustifolius que sur R. minor, et que les graines hybrides avec R. minor comme parent maternel ont un taux de germination beaucoup plus élevé. Dans des populations naturelles, on s'attend donc à ce que les hybrides de première génération soient principalement produits par R. minor. Les patterns d'hybridation ont montré que les hybrides de première génération sont formés rapidement. Dans des populations bien établies, on observe une introgression asymétrique bidirectionnelle avec généralement plus d'individus introgressés proche de R. angustifolius. Les patterns spatiaux ont révélé de fortes fluctuations dans les fréquences et/ou dans la distribution spatiale des allèles d'années en années. La forte sensibilité des populations hybrides aux facteurs environnementaux peut expliquer cette observation. L'évolution à long terme des populations hybrides est difficile à prévoir ou à modéliser car le cycle de vie annuel de ces plantes et l'absence de banque de graines persistante les rendent plus vulnérables aux changements environnementaux.Doctorat en sciences (sciences biologiques) (BIOL 3)--UCL, 200

Performance of two Rhinanthus species under different hydric conditions

Rhinanthus angustifolius and Rhinanthus minor are annual hemiparasitic herbs found in open vegetations. They are closely related, hybridize frequently, and appear to have largely overlapping niches, although some floras report a preference of R. angustifolius for more humid conditions compared to R. minor. We analysed the relative fitness of both species by following their fate from germination to seed production in three different hydric treatments (wet, moist and dry) in a garden experiment. We found that R. angustifolius was either as fit as or fitter than R. minor in all conditions and for all studied parameters, with a slightly higher flower production in R. angustifolius in the wet treatment. Wet conditions had a negative effect on germination and flowering rate, but they increased flower and seed production. These observations show that environmental conditions will influence the composition of mixed Rhinanthus populations

Outcrossing rates in two self-compatible, hybridising Rhinanthus species: implications for hybrid formation

The congeners Rhinanthus angustifolius and Rhinanthus minor, two annual hemi- parasites pollinated by bumblebees, are known to hybridise in the wild. Both spe- cies are self-compatible, but the capacity for autonomous selfing is higher in R. minor. This suggests a difference in realized outcrossing rates, which have not been determined before in these species. Using microsatellites, both species turned out to have mixed mating systems, but with a much lower multilocus outcrossing rate (0.13) for R. minor compared to R. angustifolius (0.76). We hypothesised that a higher outcrossing rate should lead to a higher chance of heterospecific pollination, and we therefore determined the rate of hybrid formation on each species in an artificial mixed population. Hybrid seeds were produced at low frequency (4.5%), and no significant difference was found between the species. It is therefore likely that post-pollination processes influence hybrid seed formation to counteract the expected difference in heterospecific pollen deposition. We checked fruit set, seed set and the rate of autonomous selfing in controlled crosses in the greenhouse in 2 years, and found that fruit set (2003) or seed set (2010) were lower in R. angus- tifolius · R. minor crosses relative to the reciprocal cross. Hybrid seeds produced on R. angustifolius also had a much lower germination rate, so most of the estab- lished F1 hybrid plants have the R. minor cytoplasm. The formation of advanced hybrids depends on pollinator preference, which is biased towards R. angustifolius if present in sufficient numbers, because it offers more rewards

New analysis of the superconducting gravimeter data of Brussels.

The study of the Earth's deep interior is the object of a spectacular development due both to new techniques of observation (including very long baseline interferometry and superconducting gravimeters) and to progress in theory spurred by new computing capability. Stimulated by the international SEDI group, founded in 1986, geophysicists from different disciplines-Earth dynamicists, seismologists, geomagneticians, mineral physicists-began to cooperate and integmte more fully one another's work. SEDI meetings favor and promote those close contacts and cooperation. Great efforts will still be needed before all the disciplinary divisions dissolve-if they ever do-but things are clearly improving, as shown by this AGU monograph. We think indeed that this volume is a good, although incomplete, illustration of the situation as described above and that it is a benchmark in the exciting story of the progress in knowledge of the deep interior of our planet

Hybridization in annual plants: patterns and dynamics during a four-year study in mixed Rhinanthus populations

Hybridization in annual plants is rare, but their short life cycle provides an excellent opportunity to study the dynamics of hybridization. Hybridization occurs between the annual hemiparasites Rhinanthus minor and Rhinanthus angustifolius (Orobanchaceae). Using flower morphology, Kwak (1980) found a prevalence of hybrids close to R. angustifolius in a single population. We aim to find whether this pattern is also found using genetic markers, whether it is generally occurring in mixed populations, and whether these populations are stable over time. We used species-specific genetic markers to determine the number of individuals in a range of hybrid classes in three mixed populations of different ages during four consecutive years. In the young population, F-1 hybrids were found in the first year and mostly hybrids between R. minor and these F(1)s in the second year, but in the years after that, hybrids close to R. angustifolius became more abundant. We also found this in the two older populations, where hybrids close to R. angustifolius always occurred in higher frequencies than hybrids close to R. minor. Over time, R. angustifolius strongly increased in frequency in two populations. Patterns of marker presence and absence suggested that advanced-generation hybrids are mainly formed by backcrossing with one of the parents, predominantly R. angustifolius whenever its frequency in the population is higher than 15%. The dynamics of mixed populations depend on the ecological conditions that regulate the presence of the two parental species, and introgression into R. angustifolius seems prevalent

Development of microsatellite markers in Rhinanthus angustifolius and cross-species amplification

Fifteen polymorphic microsatellite loci were developed from an enriched genomic library of the annual plant Rhinanthus angustifolius and characterized using 36 individuals. These markers provided high polymorphism ranging from two to 15 alleles per locus. Four loci showed significant departure from Hardy-Weinberg equilibrium, probably because of the occurrence of null alleles. No significant linkage disequilibrium was detected between pairs of loci. Tests of cross-species transferability were performed on four congeners with a success rate of 100% in Rhinanthus minor, 93% in R. mediterraneus and R. glacialis, and 80% in R. alectorolophus. These microsatellite loci will be useful tools to study mating system, gene flow and hybridization in the genus Rhinanthus