African baobabs with a very large number of stems and false stems : radiocarbon Investigation of the baobab of Warang

Author Posting. © Studia Chemia, 2017. This article is posted here by permission of Studia Chemia for personal use, not for redistribution. The definitive version was published in Studia Universitatis Babes-Bolyai, Seria Chemia 62, no. 1 (2017): 111-120, doi:10.24193/subbchem.2017.1.09.The article presents the AMS (accelerator mass spectrometry) radiocarbon dating results of the baobab of Warang, Senegal. The investigation of the baobab revealed that it consists of 18 partially fused stems, which represents the largest number of stems reported for an African baobab. Three stems build the ring that closes a false cavity, while 15 stems grow outside the ring. Seven wood samples were collected from the false cavity and from the outer part of other stems. The dating results evinced that the stems belong to four different generations, out of which the first generation is around 500 years old. We also documented the presence of false stems, which emerge from a large adjacent stem, are triangular in horizontal section and act as an anchor. The baobab of Warang possesses 12 ordinary stems and 6 false stems.The research was funded by the Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-II-ID-PCE-2013-76

La sédimentation fine sur une plate-forme interne actuelle macrotidale (la Baie de Seine sud-orientale (France))

En Baie de Seine sud-orientale (shoreface à plate-forme interne), la sédimentation fine est étudiée à des échelles de temps variées, des dépôts holocènes argilo-tourbeux continentaux (9000 ans BP) aux événements de dépôt instantanés actuels liés à des "crues estuariennes". Lors de ces crues, succédant à de faibles débits prolongés, sont combinés les apports d'un stock de sédiments fins intra-estuariens et les MES originaires du bassin versant amont. Des placages de vase se mettent alors en place dans les petits fonds ouverts sableux. Ces fonds correspondent actuellement à un contexte d'ensemble érosif, où sont mises à l'affleurement les argiles holocènes; une reconstitution lithochronostratigraphique de ces dépôts fossiles est proposée. Il est montré l'importance: à l'échelle décennale et pluri-annuelle, d'un envasement progressif des sables subtidaux et, à l'échelle de la saison, d'épisodes paroxysmiques de dépôts de vase, éphémères remaniés par les houles et les courants de marée.CAEN-BU Sciences et STAPS (141182103) / SudocPARIS-BIUSJ-Sci.Terre recherche (751052114) / SudocSudocFranceF

Origin of rippled scour depressions associated with cohesive sediments in a shoreface setting (eastern Bay of Seine, France)

Side-scan sonar investigations in the eastern part of the macrotidal Bay of Seine have revealed the presence of numerous rippled scour depressions (RSDs) at water depths of 5–9 m. The sediments in these depressions consist essentially of coarse-grained shell hash derived from underlying Holocene sediments dated at roughly 6,500 years BP, and arranged in large wave-generated ripples. The shallow marine area where these features occur consists of a wave-generated ravinement surface produced during the marine flooding of the late Holocene transgression. It can be shown that, during the last 20 years at least, erosion of the muddy sand and sandy seabed has exposed underlying relict sediments. These consist of stiff clays, silts and a layer of shell debris which, when exposed, cover the bottom of large scour depressions which appear to be in equilibrium with the local hydrodynamic regime. Morphological and hydrodynamic data suggest that the RSDs are generated by strong cross-shore bottom currents flowing parallel to the features in the direction of the prevailing waves, and probably associated with storm-induced downwelling events

Holocene to modern fine-grained sedimentation on a macrotidal shoreface-to-inner-shelf setting (eastern Bay of the Seine, France)

International audienc

Buffer Occupancy and Link State Opportunistic Routing for Wireless Mesh Networks

International audienceProviding a high level of Quality of Service (QoS) is essential for future wireless networks. This article presents a new multihop wireless routing protocol that opportunistically takes profit from variations of radio conditions in terms of path loss, shadowing and multipath fading to maximize the system capacity. However, guaranteeing high system capacity should not evade the packet delay minimization objective. Consequently, the best path should not only be considered as the path with best throughput but a combination of a good link throughput and, in addition, low router buffer occupancy load. Taking into account the available router buffer occupancy in its path selection, our proposal uses queuing theory information in order to also provide an efficient load balancing solution that adequately distributes the traffic load in the whole network. Exploiting this information, our solution dynamically adapts the selected path across time avoiding overexploited efficient links as well as low throughput link usage. This adaptation is performed considering each link state and the amount of channel information available. This improves the throughput and delay with only small marginal overhead cost. Our proposal applies to all wireless multihop networks, with increased benefit for extending cell coverage. We demonstrate through our simulation study that our solution raises the system capacity by more than 50 % in several scenarii as well as reduces packet delays compared to state-of-the-art protocols such as Ad-hoc On-demand Distance Vector (AODV), Optimized Link State Routing (OLSR) and Link State Opportunistic Routing (LSOR)

Refining the therapeutic range of posaconazole and isavuconazole for efficient therapeutic drug monitoring using a bioassay approach

International audienc

Refining the therapeutic range of posaconazole and isavuconazole for efficient therapeutic drug monitoring using a bioassay approach

International audienc

The Rim pathway mediates antifungal tolerance in Candida albicansCandida\ albicans through newly identified Rim101 transcriptional targets, including Hsp90 and Ipt1

International audienceInvasive candidiasis (IC) is a major cause of morbidity and mortality despite antifungal treatment. Azoles and echinocandins are used as first-line therapiesfor IC. However, their efficacy is limited by yeast tolerance and the emergence of acquired resistance. Tolerance is a reversible stage created due to the yeast’s capacity to counter antifungal drug exposure, leading to persistent growth. For Candida albicans, multiple stress signaling pathways have been shown to contribute to this adaptation. Among them, the pH-responsive Rim pathway, through its transcription factor Rim101p, was shown to mediate azole and echinocandin tolerance. The Rim pathway is fungus specific, is conserved among the members of the fungal kingdom, and plays a key role in pathogenesis and virulence. The present study aimed at confirming the role of Rim101p and investigating the implication of the other Rim proteins in antifungal tolerance in C. albicans, as well as the mechanisms underlying it. Time-kill curve experiments and colony formation tests showed that genetic inhibition of all the Rim factors enhances echinocandin and azole antifungal activity. Through RNA sequencing analysis of a rim101$^{-/-}$ mutant, a strain constitutively overexpressing RIM101, and control strains, we discovered novel Rim-dependent genes involved in tolerance, including HSP90, encoding a major molecular chaperone, and IPT1, involved in sphingolipid biosynthesis. Rim mutants were also hypersensitive to pharmacological inhibition of Hsp90. Taken together, these data suggest that Rim101 acts upstream of Hsp90 and that targeting the Rim pathway in combination with existing antifungal drugs may represent a promising antifungal strategy to indirectly but specifically target Hsp90 in yeasts