Magnetostratigraphic, biostratigraphic, and stable isotope stratigraphy of an Upper Miocene drill core from the Salé Briqueterie (northwestern Morocco):...

We report a high-resolution stable isotope, carbonate, magnetostratigraphic, and biostratigraphic record from a 175-m drill core from the Salé Briqueterie, which is part of the Bou Regreg section in northwestern Morocco. The Salé drill core spans the interval from paleomagnetic Chron C4n partim to C3r (earliest Gilbert), which represents the time leading up to and including the isolation and desiccation of the Mediterranean (i.e., the Messinian salinity crisis). During Chrons C3An and C3Ar (6.935 to 5.894 Ma) the isotope and carbonate signals display quasi-periodic variations with estimated periods of 40 and 100 kyr, respectively. We interpret the 40-kyr δ^18O variations as reflecting changes in global ice volume caused by obliquity-induced changes (41 kyr) in solar insolation in polar regions. The 100-kyr carbonate variations probably represent long-term modulation of the amplitude of the precessional cycle (~21 kyr), which is not resolved by our sampling frequency. The cyclic nature of the oxygen isotope signal permits us to extend the isotope nomenclature of Shackleton et al. (1994a) from stage TG24 in Chron C3r (earliest Gilbert) to stage C3Ar.δ^18O.18 at the base of Chron C3Ar (6.935 Ma). A major change in paleoceanographic conditions is recorded across the Tortonian/Messinian boundary, which we correlate to Chron C3Bn at 7.04 Ma. Benthic foraminiferal δ^18O values increased by an average of 0.4‰ in two steps at 7.17 Ma and 6.8 Ma and δ^13C values decreased by 0.7-0.8‰ between 7.1 and 6.8 Ma, representing the late Miocene carbon shift. The first step in δ^18O values coincides with an inferred reversal in deep water circulation through the Rifian Corridor, and the second correlates with the base of the Tripoli Formation and onset of "crisis conditions" in the Mediterranean. We suggest that the increase in δ^18O values represents, at least in part, an increase in global ice volume that lowered sea level and contributed to the establishment of a negative water budget in the Mediterranean. Average δ^18O values remained high throughout most of Chrons C3Ar and C3An, reaching maximum δ^18O values during isotope stages TG20 and 22 in Chron C3r (earliest Gilbert). The glacio-eustatic falls associated with these events may have resulted in the complete isolation of the Mediterranean from the world ocean (Shackleton et al., 1994a). Following stage TG12 in the Salé record, there exists a trend toward progressively lower δ^18O values that may represent a series of marine transgressions that eventually reflooded the Mediterranean and ended the Salinity Crisis

Uterine rupture in first or second trimester of pregnancy after in-vitro fertilization and embryo transfer

We report five cases of early rupture of cornual pregnancy with history of previous salpingectomy and cornual resection following in-vitro fertilization (IVF) and embryo transfer. We discuss the predisposing factors, diagnostic and therapeutic modalities in these patients. A high index of suspicion is required for an early diagnosis. It is imperative that the physicians who care for the patients be fully aware of the possibility of such a complication in a high risk population; therefore, appropriate counselling and close follow-up might help to avoid such obstetrical catastrophes, by termination of pregnancy, either surgically or medically

Self-structuring of lamellar bridged silsesquioxanes with long side spacers

Diurea cross-linked bridged silsesquioxanes (BSs) C(10)C(11)C(10) derived from organosilane precursors, including decylene chains as side spacers and alkylene chains with variable length as central spacers (EtO)(3)Si- (CH(2))(10)-Y(CH(2))(n)-Y-(CH(2))(10)-Si(OEt)(3) (n = 7, 9-12; Y = urea group and Et = ethyl), have been synthesized through the combination of self-directed assembly and an acid-catalyzed sol gel route involving the addition of dimethylsulfoxide (DMSO) and a large excess of water. This new family of hybrids has enabled us to conclude that the length of the side spacers plays a unique role in the structuring of alkylene-based BSs, although their morphology remains unaffected. All the samples adopt a lamellar structure. While the alkylene chains are totally disordered in the case of the C(10)C(7)C(10) sample, a variable proportion of all-trans and gauche conformers exists in the materials with longer central spacers. The highest degree of structuring occurs for n = 9. The inclusion of decylene instead of propylene chains as side spacers leads to the formation of a stronger hydrogen-bonded urea-urea array as evidenced by two dimensional correlation Fourier transform infrared spectroscopic analysis. The emission spectra and emission quantum yields of the C(10)C(n)C(10) Cm materials are similar to those reported for diurea cross-linked alkylene-based BSs incorporating propylene chains as side spacers and prepared under different experimental conditions. The emission of the C(10)C(n)C(10) hybrids is ascribed to the overlap of two distinct components that occur within the urea cross-linkages and within the siliceous nanodomains. Time-resolved photoluminescence spectroscopy has provided evidence that the average distance between the siliceous domains and the urea cross-links is similar in the C(10)C(n)C(10) BSs and in oxyethylene-based hybrid analogues incorporating propylene chains as side spacers (diureasils), an indication that the longer side chains in the former materials adopt gauche conformations. It has also allowed us to demonstrate for the first time that the emission features of the urea-related component of the emission of alkylene-based BSs depend critically on the length of the side spacers

RECTO : REcommandation diminuant la Congestion par Transport Optimal

National audienceThe matching setting, a particular case of recommendation problem, focuses on applications where a so-called item can be attributed to at most one user, with the job market and the matrimonial market as chief examples. In such cases, recommending the items preferred by each user might contribute to a congestion issue as users aiming at the same item cannot be all satisfied. While some state of art approaches proceed by repairing the recommendationpolicy to account for the congestion issue, other approaches take inspiration from the optimal transport (OT) framework, and aim to map the user population onto the item population in order to minimize some global transportation cost. In OT-based recommendation state-of-art approaches,the collaborative matrix (reporting the user-item matches) is interpreted as if it were the result of an OT plan ; the underlying transport cost is inferred and used e.g. to propose new congestion-avoiding recommendation policies. In this paper, another OT-based recommendation strategy is defined, noting that the collaborative matrix reflecting the individual decisions can hardly be considered as the result of a (centralized) OT plan. Accordingly, the proposed algorithm first learns a recommendation score from the data and then defines a cost matrix, with the transportation cost decreasing depending on the matching relevance. The optimal transport plan is thereafter used for the recommendation. The experimental validation of the approach presents com-parative results on benchmark data on the matrimonial market, and proprietary real-world data on the job market, illustrating the trade-off between the recall and the congestion indicators. The discussion focuses on the integration of individual and collective criteria.La recommandation de biens rivaux (sur le marché du travail ou des rencontres) fait face au danger majeur de la congestion. Pour concevoir un système de recommandation évitant la congestion, une approche possible repose sur le transport optimal, cherchant un appariement global entre l'ensemble des utilisateurs et l'ensemble des items selon un coût de transport à définir. L'originalité de l'approche RECTO (REcommandation diminuant la Congestion parTransport Optimal) est de construire le coût de transport en fonction du score de recommandation, et de définir la politique de recommandation en fonction du plan de transport entre utilisateurs et items. Une validation expérimentale comparative, menée sur une base de données publiquerelative au marché matrimonial et une base de données propriétaire relative au marché du travail, illustre le compromis entre précision et congestion. La discussion porte sur l’intégration de critères individuels et collectifs

RECTO : REcommandation diminuant la Congestion par Transport Optimal

National audienceThe matching setting, a particular case of recommendation problem, focuses on applications where a so-called item can be attributed to at most one user, with the job market and the matrimonial market as chief examples. In such cases, recommending the items preferred by each user might contribute to a congestion issue as users aiming at the same item cannot be all satisfied. While some state of art approaches proceed by repairing the recommendationpolicy to account for the congestion issue, other approaches take inspiration from the optimal transport (OT) framework, and aim to map the user population onto the item population in order to minimize some global transportation cost. In OT-based recommendation state-of-art approaches,the collaborative matrix (reporting the user-item matches) is interpreted as if it were the result of an OT plan ; the underlying transport cost is inferred and used e.g. to propose new congestion-avoiding recommendation policies. In this paper, another OT-based recommendation strategy is defined, noting that the collaborative matrix reflecting the individual decisions can hardly be considered as the result of a (centralized) OT plan. Accordingly, the proposed algorithm first learns a recommendation score from the data and then defines a cost matrix, with the transportation cost decreasing depending on the matching relevance. The optimal transport plan is thereafter used for the recommendation. The experimental validation of the approach presents com-parative results on benchmark data on the matrimonial market, and proprietary real-world data on the job market, illustrating the trade-off between the recall and the congestion indicators. The discussion focuses on the integration of individual and collective criteria.La recommandation de biens rivaux (sur le marché du travail ou des rencontres) fait face au danger majeur de la congestion. Pour concevoir un système de recommandation évitant la congestion, une approche possible repose sur le transport optimal, cherchant un appariement global entre l'ensemble des utilisateurs et l'ensemble des items selon un coût de transport à définir. L'originalité de l'approche RECTO (REcommandation diminuant la Congestion parTransport Optimal) est de construire le coût de transport en fonction du score de recommandation, et de définir la politique de recommandation en fonction du plan de transport entre utilisateurs et items. Une validation expérimentale comparative, menée sur une base de données publiquerelative au marché matrimonial et une base de données propriétaire relative au marché du travail, illustre le compromis entre précision et congestion. La discussion porte sur l’intégration de critères individuels et collectifs

RECTO : REcommandation diminuant la Congestion par Transport Optimal

National audienceThe matching setting, a particular case of recommendation problem, focuses on applications where a so-called item can be attributed to at most one user, with the job market and the matrimonial market as chief examples. In such cases, recommending the items preferred by each user might contribute to a congestion issue as users aiming at the same item cannot be all satisfied. While some state of art approaches proceed by repairing the recommendationpolicy to account for the congestion issue, other approaches take inspiration from the optimal transport (OT) framework, and aim to map the user population onto the item population in order to minimize some global transportation cost. In OT-based recommendation state-of-art approaches,the collaborative matrix (reporting the user-item matches) is interpreted as if it were the result of an OT plan ; the underlying transport cost is inferred and used e.g. to propose new congestion-avoiding recommendation policies. In this paper, another OT-based recommendation strategy is defined, noting that the collaborative matrix reflecting the individual decisions can hardly be considered as the result of a (centralized) OT plan. Accordingly, the proposed algorithm first learns a recommendation score from the data and then defines a cost matrix, with the transportation cost decreasing depending on the matching relevance. The optimal transport plan is thereafter used for the recommendation. The experimental validation of the approach presents com-parative results on benchmark data on the matrimonial market, and proprietary real-world data on the job market, illustrating the trade-off between the recall and the congestion indicators. The discussion focuses on the integration of individual and collective criteria.La recommandation de biens rivaux (sur le marché du travail ou des rencontres) fait face au danger majeur de la congestion. Pour concevoir un système de recommandation évitant la congestion, une approche possible repose sur le transport optimal, cherchant un appariement global entre l'ensemble des utilisateurs et l'ensemble des items selon un coût de transport à définir. L'originalité de l'approche RECTO (REcommandation diminuant la Congestion parTransport Optimal) est de construire le coût de transport en fonction du score de recommandation, et de définir la politique de recommandation en fonction du plan de transport entre utilisateurs et items. Une validation expérimentale comparative, menée sur une base de données publiquerelative au marché matrimonial et une base de données propriétaire relative au marché du travail, illustre le compromis entre précision et congestion. La discussion porte sur l’intégration de critères individuels et collectifs