Stratification and productivity in the in the Western Tethys (NW Algeria) during early Toarcian

17 pagesInternational audienceProfound environmental changes punctuated the Early Jurassic period, as recorded by marked carbon and oxygen isotope anomalies and major biotic crises. The response of low-latitude regions of Northern Gondwana to such intense changes is not documented as well as that of other Tethys areas. We present new calcareous nannofossil assemblages from three sections located in NW Algeria, in the Sahara and Tlemcen Basins, respectively. New stable carbon and nitrogen isotope data are provided from the Tlemcen Basin to reconstruct local environmental conditions in the wider context of a Toarcian greenhouse climate. We first established a solid chemo- and biostratigraphic framework by integrating stable carbon isotope data and calcareous nannofossil events. Calcareous nannofossil assemblages show common trends in the two basins, such as the occurrence in high proportions of the deep-dweller species Mitrolithus jansae, likely indicating stratification of the water column with a deep nutricline. This taxon dominated the assemblage during the negative carbon isotope excursion (CIE) interval, often used to delineate the base of the Toarcian anoxic event (T-OAE). Such a nannofossil record is unique in the Western Tethys domain, as M. jansae is known to drastically decrease in abundance during the T-OAE until its disappearance in the aftermath of the event. The NW Algeria nannofossil record indicates prolonged thermal stratification of water-masses, finally triggering hyper-oligotrophy and low productivity in shallow waters during the Toarcian CIE. Such peculiar conditions are likely related to the combined effects of a warm and arid climate dominating along the northern Gondwana margin and the presence of a strong clockwise gyre over the epicontinental shelf, which brought warm equatorial waters from the Tethys Ocean to the NW Algeria shelf

Artificial intelligence outperforms pulmonologists in the interpretation of pulmonary function tests

The interpretation of pulmonary function tests (PFTs) to diagnose respiratory diseases is built on expert opinion that relies on the recognition of patterns and the clinical context for detection of specific diseases. In this study, we aimed to explore the accuracy and interrater variability of pulmonologists when interpreting PFTs compared with artificial intelligence (AI)-based software that was developed and validated in more than 1500 historical patient cases.120 pulmonologists from 16 European hospitals evaluated 50 cases with PFT and clinical information, resulting in 6000 independent interpretations. The AI software examined the same data. American Thoracic Society/European Respiratory Society guidelines were used as the gold standard for PFT pattern interpretation. The gold standard for diagnosis was derived from clinical history, PFT and all additional tests.The pattern recognition of PFTs by pulmonologists (senior 73%, junior 27%) matched the guidelines in 74.4±5.9% of the cases (range 56-88%). The interrater variability of κ=0.67 pointed to a common agreement. Pulmonologists made correct diagnoses in 44.6±8.7% of the cases (range 24-62%) with a large interrater variability (κ=0.35). The AI-based software perfectly matched the PFT pattern interpretations (100%) and assigned a correct diagnosis in 82% of all cases (p<0.0001 for both measures).The interpretation of PFTs by pulmonologists leads to marked variations and errors. AI-based software provides more accurate interpretations and may serve as a powerful decision support tool to improve clinical practice.status: publishe