Occurrence of an Intersexual Blacktip Shark in the Northern Gulf of Mexico, with Notes on the Standardization of Classifications for This Condition in Elasmobranchs

An intersexual Blacktip Shark Carcharhinus limbatus with a testis, immature female reproductive tracts (embedded), and claspers was caught in the Gulf of Mexico. Histology of the single gonad revealed that all stages of spermatogenesis were occurring; however, the absence of ovaries and a male duct system suggests that neither sex would have been functional in this individual. Intersexuality has been reported in 17 families and 36 species of elasmobranchs. The degree to which the different sexes are present in a given individual is often difficult to categorize by normal hermaphroditic standards, as this is typically an anomalous presentation in elasmobranchs. Therefore, this report provides three categories for classification (basic, incomplete, and complete intersexuality) to standardize terminology and allow for more precise comparisons to be made among elasmobranch examples. Basic intersexuals have gonadal tissue of only one sex and a combination of other male and female characters with neither or only one sex being complete. Incomplete intersexuals have gonadal tissue of both sexes and a combination of other male and female characters; however, neither or only one sex is complete. Complete intersexuals have claspers as well as gonadal tissue and tracts for both sexes. The majority of the reported intersexual elasmobranchs, including the shark described here, are basic intersexuals

A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae)

Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (<12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques

Increased maternal TSH and decreased maternal FT4 are associated with a higher operative delivery rate in low-risk pregnancies: A prospective cohort study

Background:  The increasing number of operative deliveries is a topic of major concern in modern obstetrics. Maternal thyroid function is of known influence on many obstetric parameters. Our objective was to investigate a possible relation between maternal thyroid function, and operative deliveries. Secondary aim was to explore whether thyroid function was related to specific reasons for operative deliveries. Methods:  In this prospective cohort study, low-risk Caucasian women, pregnant of a single cephalic fetus were included. Women with known auto-immune disease, a pre-labour Caesarean section, induction of labour, breech presentation or preterm delivery were excluded. In all trimesters of pregnancy the thyroid function was assessed. Differences in mean TSH and FT4 were assessed using t-test. Mean TSH and FT4 levels for operative deliveries were determined by one way ANOVA. Repeated measurement analyses were performed (ANOVA), adjusting for BMI, partiy, maternal age and gestational age at delivery. Results:  In total 872 women were included, of which 699 (80.2 %) had a spontaneous delivery. At 36 weeks gestation women who had an operative delivery had a significantly higher mean TSH (1.63mIU/L versus 1.46mIU/L, p = 0.025) and lower mean FT4 (12.9pmol/L versus 13.3pmol/L, p = 0.007)) compared to women who had a spontaneous delivery. Mean TSH was significantly higher (p = 0.026) and mean FT4 significantly lower (p = 0.030) throughout pregnancy for women with an operative delivery due to failure to progress in second stage of labour, compared to women with a spontaneous delivery or operative delivery for other reasons. Conclusion:  Increased TSH and decreased FT4 seem to be associated with more operative vaginal deliveries and Caesarean sections. After adjusting for several confounders the association remained for operative deliveries due to failure to progress in second stage of labour, possibly to be explained by less efficient uterine action

Estimation of fetal weight: accuracy of regression models versus accuracy of ultrasound data

OBJECTIVES: To determine the respective importance of equation accuracy and variability in interexaminer measurements in estimation of fetal weight (EFW). METHODS: The study included 3 samples from three different French maternity hospitals. Sample 1 (6,508 fetuses) was used to compute a new linear regression model estimating fetal weight (FW) from ultrasound measurements. Sample 2, with 705 fetuses, was used to compare the accuracy of the new equation with Hadlock's equation. Sample 3 (1,461 fetuses) was used to assess - from our equation and from Hadlock's - the estimation errors due to the variability of ultrasound measurements recorded by 11 distinct examiners. Accuracy was determined by the signed percent difference (%Diff). Statistical analysis included the F test for correlated variances and comparisons of correlated variances. RESULTS: The random error of our model is 6.8%, significantly lower (p < 0.01) than Hadlock's which is around 7.4% (8.9% for low FW and 7.4% for high FW). The variability of ultrasound measurements among the different examiners in sample 3 generated a significant variation (p < 0.01) in the random error, ranging from 6.7 to 12.5%. This significant variation was also observed using Hadlock's equation for the same sample (from 7.2 to 12%). CONCLUSION: The accuracy of EFW depends much more on the quality of ultrasound measurements than on the choice of equation. Nevertheless, optimizing the accuracy of EFW (about 6.7-6.8%) imperatively requires standardized data collecting

Etude des paléoméandres holocènes de la plaine alluviale du Cher (site de Bigny, moyenne vallée du Cher)

International audienceL’identification de paléochenaux dans les plaines alluviales permet d’apporter des éléments de compréhension des morphologies et des processus fluviaux passés. L’étude présentée porte sur le secteur de Bigny, localisé dans la moyenne vallée du Cher, où se trouve un nombre important de paléoméandres, dont certains sont datés de la seconde moitié de l’Holocène. La démarche méthodologique mise en œuvre comprend l’étude de MNT LiDAR, la caractérisation des formes fluviales héritées (altitude, largeur, amplitude et rayon de courbure) et l’estimation de paramètres paléohydrauliques à partir des dimensions des chenaux abandonnés (paléodébits à pleins-bords). Les résultats permettent de disposer les premiers jalons d’une chronologie d’évolution paléohydrographique. La comparaison avec la morphologie locale de la rivière et avec les cartes historiques montre que la réduction de la sinuosité a eu lieu entre le Moyen-Âge et l’Epoque Moderne. Elle démontre également la stabilisation du tracé du Cher dans ce secteur depuis le milieu du XVIIIème siècle, probablement en lien avec des aménagements hydrauliques historiques. L’analyse morphométrique permet ensuite de distinguer des gabarits variés parmi lesquels des paléoméandres de grande taille. Néanmoins, la comparaison des paléoméandres avec le référentiel actuel montre que la série étudiée est proche du gabarit des chenaux du XIXème siècle. On ne peut donc pas conclure à un changement majeur de régime hydrologique enregistré par les paléoméandres, mais plutôt à des ajustements mineurs de la morphologie des chenaux (largeur, profondeur) liés à des modifications des débits liquides et solides