New organic-walled dinoflagellate cysts from recent sediments of central Asian seas

Recent to sub-recent sediments from the Caspian Sea, the Kara-Bogaz-Gol Bay, the Enseli lake and the Aral Sea contain the new organic-walled dinoflagellate cysts Caspidinium, Caspidinium rugosum and Impagidinium caspienense. Caspidinium rugosum has S-type paratabulation, dextral torsion and low relief intratabular ornamentation. Impagidinium caspienense has low intratabular suturo-cavate relief, parasutural septa irregular in height and a high septum at the junction of paraplate 1'''' and the sulcus. The accompanying species consist of Spiniferites cruciformis, Lingulodinium machaerophorum, Pyxidinopsis psilata, cysts of Pentapharsodinium dalei and Brigantedinium spp. Spiniferites cruciformis varies from specimens with a cruciform body with a well-developed postero-lateral membranous flange to specimens with a pear-shaped body, reduced processes and no flange. Sea-surface data from these Central Asian seas suggests that the two new taxa Caspidinium rugosum and Impagidinium caspienense are probably related to low salinity conditions (12-13)

Deep Learning-based Universal Beamformer for Ultrasound Imaging

In ultrasound (US) imaging, individual channel RF measurements are back-propagated and accumulated to form an image after applying specific delays. While this time reversal is usually implemented using a hardware- or software-based delay-and-sum (DAS) beamformer, the performance of DAS decreases rapidly in situations where data acquisition is not ideal. Herein, for the first time, we demonstrate that a single data-driven adaptive beamformer designed as a deep neural network can generate high quality images robustly for various detector channel configurations and subsampling rates. The proposed deep beamformer is evaluated for two distinct acquisition schemes: focused ultrasound imaging and planewave imaging. Experimental results showed that the proposed deep beamformer exhibit significant performance gain for both focused and planar imaging schemes, in terms of contrast-to-noise ratio and structural similarity.Comment: Accepted for MICCAI 2019. arXiv admin note: substantial text overlap with arXiv:1901.0170

The contribution of the middle cerebral artery and callosal artery to the vascularisation of the Facies convexa of the brain in horses with reference to the equine-specific cartographic pattern of the neopallium

Background: The extremely complex surface architecture of the equine brain does not allow a uniform transfer of anatomical data from other mammalian species, e.g., dog or cat. Rather, a special approach is required to elucidate the equine-specific patterns of cerebral vascular ramifications. Therefore, a novel cartographic system was applied. Prior attention was paid to the A. cerebri media (MCA) and to the A. corporis callosi (CA), as they spread over the widest part of the neopallium’s Facies convexa (i.e. the lateral and dorsal surface), thus being of particular interest in terms of surgical treatment of trauma of the skull and brain. Materials and methods: The brains of 17 adult warmblood horses were studied. The neopallium’s Facies convexa was subdivided into 15 sectors clearly delineated by the primary sulci and by related auxiliary lines. The courses and destinations of main branches (= branches of 1st or 2nd order, with a minimum calibre of 0.75 mm) of MCA and CA were topographically analysed by means of superimposed graphical sketches. Results: The MCA had six main branches (numbered in rostrocaudal direction); the CA had seven main branches. The main branches of the MCA spread over the widest part of the Facies convexa, but never reached the rostral pole and the caudal pole of the neopallium. Clearly, the main branches of CA proceeded from the hemisphere’s medial side across the Margo dorsalis cerebri, thus supplying rostrodorsal and dorsal sectors of the Facies convexa. Conclusions: The topographical analysis of the vascular ramification patterns (regions of residence) in combination with the cartographic system of sectors of the neopallium respected the equine-specific surface architecture. It highlighted the distinct vascular supply areas and the particular multiple-supply situations especially in sectors presumably related to the equine area motorica

Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora

Background The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora - South Africa's biodiversity hotspot - through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years. Results Forty-three distributional and phenological shifts consistent with past climatic change occur across the flora, and a comparable number of clades underwent adaptive changes in their flowering phenology (9 clades; half of the clades investigated) as underwent distributional shifts (12 clades; two thirds of the clades investigated). Of extant Cape angiosperm species, 14-41% have been contributed by lineages that show distributional shifts consistent with past climate change, yet a similar proportion (14-55%) arose from lineages that shifted flowering phenology. Conclusions Adaptive changes in ecology at the scale we uncover in the Cape and consistent with past climatic change have not been documented for other floras. Shifts in climate tolerance appear to have been more important in this flora than is currently appreciated, and lineages that underwent such shifts went on to contribute a high proportion of the flora's extant species diversity. That shifts in phenology, on an evolutionary timescale and on such a scale, have not yet been detected for other floras is likely a result of the method used; shifts in flowering phenology cannot be detected in the fossil record

Hydrologie et géochimie isotopique

Cet ouvrage rassemble des travaux récents dans les domaines de l'hydrologie et de la géochimie isotopique. La première partie explore le cycle des eaux naturelles, depuis les précipitations jusqu'aux aquifères profonds, par l'analyse des variations de la composition isotopique de l'hydrogène, de l'oxygène et du carbone. Des types régionaux sont présentés, sous diverses latitudes : Spitzberg, Bassin parisien, bassin soudano-sahélien du Niger. L'intérêt de l'approche isotopique dans l'étude du changement global est illustrée en deuxième partie. Les variations hydro-climatiques de types régionaux, en Afrique essentiellement, sont retracées par l'analyse multidisciplinaire d'enregistrements sédimentaires, dont la géochimie isotopique constitue la clé essentielle. L'homogénéité du refroidissement, aux moyennes et basses latitudes, lors du dernier maximum glaciaire est démontrée par l'analyse isotopique des gaz nobles dans les eaux souterraines. La mise en évidence de l'origine organique du carbone de carbonates sédimentaires remet en question l'interprétation de certaines analyses isotopiques. La troisième partie fait référence aux isotopes d'origine cosmique et à la production in situ de radionucléides. Il est rappelé que la datation par 14C a contribué à la compréhension des mécanismes des changements du climat au cours du dernier maximum glaciaire et depuis lors. Les limites de cette méthode et ses progrès récents font l'objet d'une synthèse amplement documentée. Par l'apport de données isotopiques, la géochimie s'avère fonder la modélisation des conditions de stabilité du réacteur de fission nucléaire fossile d'Oklo. (Résumé d'auteur