9 research outputs found

    Upper Pleistocene comparativeOSL, U/Th and 14C datings of sedimentary sequences and correlative morphodynamical implications in the South-Western Anti-Atlas (Oued Noun, 29° N, Morocco)

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    The lower Oued Noun valley, in the arid region of the Atlantic SW Anti-Atlas, contains an extensive Soltanian (= Upper Pleistocene pro-parte) terrace. The paper presents dates for these deposits and an interpretation of their fluvial dynamic and morpho-climatic geneses in this distal part of the valley.The Soltanian terrace, about 30 m thick at Fort Oued Noun, consists of 3 units: a basal deposit of coarse gravel buried by slope deposits and travertine (Unit 1); a main unit, more than 20 m thick (Unit 2) that consists of at least 7 repeated sequences each comprising basal fine gravels and sands, associated with detrital travertine, overlain by stromatolithic tufa and finally by a thick accumulation of sandy silts. These silts were deposited by suspension and decantation in shallow non-turbulent water bodies. The gravels, sands and travertines are more prominent at the bottom and in the upper parts of Unit 2 whilst silts dominate the mid members. Middle Paleolithic artefacts and bones of large mammals are found throughout this Unit.Unit 3, at the top of the formation, comprises red silts that differ from those of Unit 2, containing more aeolian grains and more palygorskyte and being spatially associated with adjacent tributaries fans.Radiometric dates were obtained on travertine (U/Th), on quartz grains extracted from sediments (OSL) and on Melanopsis and Charcoal (14C). U/Th results show three travertine constructions at ca 90, 55-50 and 25-20 ka B.P. The 90 ka dates, however, are not in correct stratigraphic position. The OSL dates suggest that the period of silt aggradation of Unit 2 occured between ca. 50 and 25 ka B.P., the main part of them being deposited between 40 and 30 ka B.P. 14C dates from the upper part of Unit 2 and the base of Unit 3, range between ca 28 and 18 ka B.P. These dates, together with geomorphological and sedimentological analyses, indicate that the valley floor had been lowered to its present depth before ca. 90 ka B.P. However, the slope deposits, older travertines and the basal gravel (Unit 1), classic fluvial and colluvial deposits, are not yet securely dated but they possibly correspond with wetter episodes in O.I.S. stages 5b, 5a and 4, or even later. The silts that form the bulk of Unit 2 were deposited into shallow swamps during biostasic episodes of O.I.S. 3 and were associated with high groundwater levels. Then, large mammals found grass and water along the valley and were hunted by Middle Paleolithic people. The water table remained high after 30 ka B.P. and the gravel-bed channels of the local tributaries were active during the 30-20 ka B.P. period. After ca. 20 ka, sediments suggest more varied conditions in this part of the valley, vegetation disappeared and soils were reworked into local colluvial fans, with concomitant aeolian deposits (Unit 3, O.I.S. 2). Finally, deep linear incision occured dissecting the Soltanian aggraded valley floor during the early Holocene.La basse vallée de l'oued Noun, aujourd'hui située dans le domaine aride du versant sud de l'Anti-Atlas, montre une terrasse soltanienne (Pléistocène supérieur pro-parte) bien développée. Les objectifs de cet article sont de déterminer avec précision les âges des sédiments et de comprendre les changements de la dynamique fluviale, avec ses phases successives d’aggradation et d’érosion, à la fin du Pléistocène supérieur.La formation soltanienne, épaisse de 30 m à Fort Oued Noun, se compose de 3 unités : un dépôt conglomératique de base surmonté par des dépôts de pente et à des travertins (Unité 1) ; un dépôt principal de plus de 20 m (Unité 2), qui consiste en au moins 7 séquences répétitives montrant chacune à la base des petits galets et des sables associés à des travertins détritiques, surmontés de travertins stromatolithiques construits finalement recouverts d'accumulations épaisses de limons. Ces limons ont été déposés par suspension et décantation dans des eaux calmes et peu profondes. Les galets, sables et travertins sont surtout fréquents à la base et au sommet de l’Unité 2, tandis que les limons dominent dans sa partie moyenne. Dans toute l’Unité 2, on trouve des ossements de grands mammifères et des outillages lithiques du Paléolithique moyen. Au sommet de la formation, des limons rouges supérieurs (Unité 3) diffèrent des précédents et appartiennent à des cônes déposés par les affluents locaux, avec davantage de grains éoliens et de palygorskyte.Les datations radiométriques ont été obtenues  pour des travertins (U/Th), des grains de quartz extraits des sédiments (OSL), des charbons et Melanopsis (14C). Les datations U/Th montrent trois périodes de construction de travertins autour de 90, 55-50 et 25-20 ka B.P. Les résultats à 90 ka ne sont toutefois pas en bon accord avec la stratigraphie. D'après les résultats OSL, la période d'aggradation des silts de l'Unité 2 se situe entre environ 50 et 25 ka B.P., la majeure partie de ces silts se déposant entre 40 et 30 ka B.P. Les datations 14C se rangent entre 28 et 18 ka B.P. Elles concernent la partie supérieure de l'Unité 2 et la partie basale de l'Unité 3.Ces résultats, associés aux observations géomorphologiques et sédimentologiques, montrent que la vallée était déjà creusée autour de 90 ka B.P. Les dépôts de pente, les plus anciens travertins et le dépôt basal graveleux, ayant tous une signature de dépôts colluviaux ou alluviaux classiques, ne sont pas datés avec sûreté ; ils peuvent correspondre à des épisodes humides des stages isotopiques 5b, 5a et 4, mais peuvent aussi être plus récents. Les silts qui forment la masse de l'Unité 2 ne peuvent être reliés uniquement à une activité fluviale et ont été déposés dans des étendues d'eaux calmes liées à une élévation concomitante du niveau des nappes phréatiques durant des épisodes biostasiques du stage isotopique 3. De grands mammifères ont alors pu trouver de l'eau et de l'herbe dans la vallée et être chassés par les hommes du Paléolithique moyen. La nappe phréatique s'est maintenue à un niveau élevé après 30 ka B.P et les chenaux à graviers des affluents locaux sont restés actifs durant la période 30-20 ka B.P. Après cette date, l’instabilité s’est accrue ; dans cette partie de la vallée, la végétation s'est raréfiée, les sols ont été remaniés, édifiant des cônes locaux où s'observent aussi des influences éoliennes (Unité 3, stage isotopique 2). Enfin, une forte incision linéaire s’est produite à l’Holocène inférieur, disséquant l'accumulation soltanienne

    A prospective, observational study of fidaxomicin use for Clostridioides difficile infection in France.

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    To describe the characteristics, management and outcomes of hospitalised patients with Clostridioides difficile infection (CDI) treated with and without fidaxomicin. This prospective, multicentre, observational study (DAFNE) enrolled hospitalised patients with CDI, including 294 patients treated with fidaxomicin (outcomes recorded over a 3-month period) and 150 patients treated with other CDI therapies during three 1-month periods. The primary endpoint was baseline and CDI characteristics of fidaxomicin-treated patients. At baseline, the fidaxomicin-treated population included immunocompromised patients (39.1%) and patients with severe (59.2%) and recurrent (36.4%) CDI. Fidaxomicin was associated with a high rate of clinical cure (92.2%) and low CDI recurrence (16.3% within 3 months). Clinical cure rates were ≥90% in patients aged ≥65 years, those receiving concomitant antibiotics and those with prior or severe CDI. There were 121/296 (40.9%) patients with adverse events (AEs), 5.4% with fidaxomicin-related AEs and 1.0% with serious fidaxomicin-related AEs. No fidaxomicin-related deaths were reported. Fidaxomicin is an effective and well-tolerated CDI treatment in a real-world setting in France, which included patients at high risk of adverse outcomes.Trial registration: Description of the use of fidaxomicin in hospitalised patients with documented Clostridium difficile infection and the management of these patients (DAFNE), NCT02214771, www.ClinicalTrials.gov

    Datations OSL, U/Th et14C croisées de séquences sédimentaires du Pléistocène supérieur et leurs implications morphodynamiques (Oued Noun, sud-ouest de l'Anti-Atlas, 29° N, Maroc)

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    International audienceThe lower Oued Noun valley, in the arid region of the Atlantic SW Anti-Atlas, contains an extensive Soltanian (= Upper Pleistocene pro-parte) terrace. The paper presents dates for these deposits and an interpretation of their fluvial dynamic and morpho-climatic geneses in this distal part of the valley. The Soltanian terrace, about 30 m thick at Fort Oued Noun, consists of 3 units: a basal deposit of coarse gravel buried by slope deposits and travertine (Unit 1); a main unit, more than 20 m thick (Unit 2) that consists of at least 7 repeated sequences each comprising basal fine gravels and sands, associated with detrital travertine, overlain by stromatolithic tufa and finally by a thick accumulation of sandy silts. These silts were deposited by suspension and decantation in shallow non-turbulent water bodies. The gravels, sands and travertines are more prominent at the bottom and in the upper parts of Unit 2 whilst silts dominate the mid members. Middle Paleolithic artefacts and bones of large mammals are found throughout this Unit. Unit 3, at the top of the formation, comprises red silts that differ from those of Unit 2, containing more aeolian grains and more palygorskyte and being spatially associated with adjacent tributaries fans. Radiometric dates were obtained on travertine (U/Th), on quartz grains extracted from sediments (OSL) and on Melanopsis and Charcoal (14 C). U/Th results show three travertine constructions at ca 90, 55-50 and 25-20 ka B.P. The 90 ka dates, however, are not in correct stratigraphic position. The OSL dates suggest that the period of silt aggradation of Unit 2 occured between ca. 50 and 25 ka B.P., the main part of them being deposited between 40 and 30 ka B.P. 14 C dates from the upper part of Unit 2 and the base of Unit 3, range between ca 28 and 18 ka B.P. These dates, together with geomorphological and sedimentological analyses, indicate that the valley floor had been lowered to its present depth before ca. 90 ka B.P. However, the slope deposits, older travertines and the basal gravel (Unit 1), classic fluvial and colluvial deposits, are not yet securely dated but they possibly correspond with wetter episodes in O.I.S.stages 5b, 5a and 4, or even later. The silts that form the bulk of Unit 2 were deposited into shallow swamps during biostasic episodes of O.I.S. 3 and were associated with high groundwater levels. Then, large mammals found grass and water along the valley and were hunted by Middle Paleolithic people. The water table remained high after 30 ka B.P. and the gravel-bed channels of the local tributaries were active during the 30-20 ka B.P. period. After ca. 20 ka, sediments suggest more varied conditions in this part of the valley, vegetation disappeared and soils were reworked into local colluvial fans, with concomitant aeolian deposits (Unit 3, O.I.S. 2). Finally, deep linear incision occured, dissecting the Soltanian aggraded valley floor during the early Holocene. RÉSUMÉ DATATIONS OSL, U/Th ET 14 C CROISÉES DE SÉQUENCES SÉDIMENTAIRES DU PLÉISTOCÈNE SUPÉRIEUR ET LEURS IMPLICATIONS MORPHODYNAMIQUES (OUED NOUN, SUD-OUEST DE L'ANTI-ATLAS, 29 o N, MAROC) La basse vallée de l'oued Noun, aujourd'hui située dans le domaine aride du versant sud de l'Anti-Atlas, montre une terrasse soltanienne (Pléistocène supérieur pro-parte) bien développée. Les objectifs de cet article sont de déterminer avec précision les âges des sédiments et de com-prendre les changements de la dynamique fluviale, avec ses phases successives d'aggradation et d'érosion, à la fin du Pléistocène supérieur. La formation soltanienne, épaisse de 30 m à Fort Oued Noun, se compose de 3 unités : un dépôt conglomératique de base surmonté par des dépôts de pente et des travertins (Unité 1) ; un dépôt principal de plus de 20 m (Unité 2), qui consiste en au moins 7 séquences répétitives mon-trant chacune à la base des petits galets et des sables associés à des travertins détritiques, surmontés de travertins stromatolithiques construits finale-ment recouverts d'accumulations épaisses de limons. Ces limons ont été déposés par suspension et décantation dans des eaux calmes et peu profondes. Les galets, sables et travertins sont surtout fréquents à la base et au sommet de l'Unité 2, tandis que les limons dominent dans sa parti

    Scedosporiosis/lomentosporiosis observational study (SOS): Clinical significance of Scedosporium species identification

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    International audienceScedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes. We retrospectively studied cases of invasive scedosporiosis in France from 2005 through 2017 based on isolates characterized by polyphasic approach. We recorded 90 cases, mainly related to Scedosporium apiospermum (n = 48), S. boydii/S. ellipsoideum (n = 20), and Lomentospora prolificans (n = 14). One-third of infections were disseminated, with unexpectedly high rates of cerebral (41%) and cardiovascular (31%) involvement. In light of recent Scedosporium taxonomic revisions, we aimed to study the clinical significance of Scedosporium species identification and report for the first time contrasting clinical presentations between infections caused S. apiospermum, which were associated with malignancies and cutaneous involvement in disseminated infections, and infections caused by S. boydii, which were associated with solid organ transplantation, cerebral infections, fungemia, and early death. The clinical presentation of L. prolificans also differed from that of other species, involving more neutropenic patients, breakthrough infections, fungemia, and disseminated infections. Neutropenia, dissemination, and lack of antifungal prescription were all associated with 3-month mortality. Our data support the distinction between S. apiospermum and S. boydii and between L. prolificans and Scedosporium sp. Our results also underline the importance of the workup to assess dissemination, including cardiovascular system and brain. Lay Summary Scedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes

    Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

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    International audienceThe aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed

    COVID-19 Host Genetics Initiative. A first update on mapping the human genetic architecture of COVID-19

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    The COVID-19 pandemic continues to pose a major public health threat, especially in countries with low vaccination rates. To better understand the biological underpinnings of SARS-CoV-2 infection and COVID-19 severity, we formed the COVID-19 Host Genetics Initiative1. Here we present a genome-wide association study meta-analysis of up to 125,584 cases and over 2.5 million control individuals across 60 studies from 25 countries, adding 11 genome-wide significant loci compared with those previously identified2. Genes at new loci, including SFTPD, MUC5B and ACE2, reveal compelling insights regarding disease susceptibility and severity.</p

    Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

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    A first update on mapping the human genetic architecture of COVID-19

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