Thrusting implication in the crustal thickening history of eastern Tibet is highly debated. The ∼250 km‐long Muli thrust of the Yalong thrust belt in SE Tibet is a major Miocene structure with a ...pronounced topographic step (∼2,000 m). Using thermo‐kinematic modeling based on thermochronology data, we constrain the crustal geometry of the thrust as being steep (>70°) at the surface, in agreement with field observations, and flattening at depth (≥20 km) on an intra‐crustal décollement. Thrusting motion on the fault shows a velocity of 0.2 ± 0.06 km/Ma since 50 Ma, followed by an acceleration at a rate of 0.6 ± 0.08 km/Ma starting at 12.5 ± 1 Ma, yielding a total of ∼15 km of exhumed crust. Deeper, deformation may be localized through a ductile shear zone, and be related to the ∼15 km Moho step and shear wave velocity contrast imaged by tomography beneath the Yalong thrust belt.
Plain Language Summary
The India‐Eurasia collision (∼50 million years ago Ma) led to the formation of the Tibetan Plateau, the world's largest and highest orogenic plateau. The formation and evolution of such a unique geological feature has been one of the main controversies in Earth Sciences for decades, especially regarding the role of faulting in the thickening of the crust. Here, we present 3D thermo‐kinematic models of thermochronology data allowing to constrain the exhumation history of the Muli thrust fault, a ∼250 km‐long major structure of the SE Tibetan margin, linked to significant steps in surface topography and in crustal boundary at depth (Moho). We constrain a steep fault (>70°) within the upper crust, consistent with field observations, that flattens at depth (≥20 km). The Muli thrust presents rapid thrusting motion (0.6 ± 0.08 km/Ma) that initiated at ∼12.5 Ma, following a slower phase (0.2 ± 0.06 km/Ma) since 50 Ma, with total rock exhumation of ∼15 km. This underlines the important role of thrust faulting in the thickening of the SE Tibetan crust.
Key Points
Thermo‐kinematic modeling of Muli thrust, a major thrust fault of SE Tibetan Plateau
15 km crust exhumation in 50 Ma on a high‐angle (>70°) ramp—décollement fault linked to thickening of SE Tibetan crust
Fault related to significant Moho step and shear wave velocity contrast in deep crust suggests entire crust implication
Collisional shortening in the external Western Alps was first accommodated by internal (distributed) deformation in the External Crystalline Massifs (ECM) and then on frontal crustal ramps (localized ...deformation). However, the timing of transition between these two periods is still under-constrained, mainly because the available dataset is incomplete in the Western Alps. We here provide new zircon and apatite fission-track (ZFT and AFT) and zircon (U-Th-Sm)/He (ZHe) data that constrain the early stages of cooling hence exhumation of the external Alpine wedge, as well as new Raman Spectroscopy of Carbonaceous Material (RSCM) data from the Belledonne massif. ZFT ages mainly range between 15 and 20 Ma, ZHe ages between 5 and 12 Ma, AFT ages between 2 and 10 Ma. Those data are integrated within inverse and forward thermal history modelling (HeFTy) along with literature data to constrain the late Oligocene-Miocene cooling history and suggest that exhumation of the Belledonne and the Pelvoux massifs may have started as early as ca. 27 Ma. This early exhumation was rather slow (~ 50 m.Myrs−1 ± 2 m.Myrs−1) and may date the transition between the distributed and the localized mode of shortening, i.e., the initiation of the crustal ramps below these massifs. Further north, in the Mont Blanc and Aiguilles Rouges massifs, exhumation was active around 18 Ma, and started possibly earlier, around 20–25 Ma. From this time on (18 Ma), exhumation rates increased in all external massifs (~ 500 ± 40 m.Myrs−1, both North and South). This age most likely corresponds to the end of the transition period between distributed and localized shortening with localisation along the frontal crustal ramps and the rapid associated exhumation, then cooling of the hangingwall (even considering that cooling may start a few Myrs later than exhumation if isoterms are advected). This timing notably corresponds to a transition between the two molasse mega-sequences in the foreland basin (Lower Marine/Freshwater Molasse and Upper Marine/Freshwater Molasse).
•Insight into External Crystalline Massifs cooling/exhumation during the Oligo-Miocene period.•ZFT ages range between 15 and 20 Ma, ZHe ages between 5 and 12 Ma, AFT ages between 2 and 10 Ma.•South ECMs record an early and slow exhumation at ca. 27 whereas North ECMs record a rapid exhumation at ca. 18 Ma.•18 Ma correspond to the end of the transition period between distributed and localized shortening.
Constraining the way in which continental deformation is accommodated in time and space is essential to reconcile past plate movements with geological observations. Kinematic reconstructions of the ...Iberia‐Europe plate boundary are still debated. Here we focus on an inverted Mesozoic rift basin, the Cameros basin, which is part of the Iberian chain. We use a combination of detrital low‐temperature thermochronological techniques to define the time‐temperature evolution of the basin from Mesozoic rifting to Cenozoic collision. Zircon fission‐track analyses of Oligocene–Miocene sedimentary rocks yield two main age populations at ~170 ± 10 and ~100 ± 10 Ma, reflecting (i) an Early Jurassic thermal event related to the Atlantic‐Alpine Tethys opening and (ii) an Albo‐Cenomanian thermal event related to the Bay of Biscay opening. Thermal modeling of combined zircon fission‐track, apatite fission‐track, and apatite (U‐Th‐Sm)/He data reveals that collision‐related cooling of the Cameros basin started during the Paleocene (~60 Ma). A second cooling/exhumation phase of the basin is recorded from 35 to 25 Ma. Initial cooling occurred after a protracted postrift period characterized by persistence of high geothermal gradients, a feature also recognized in the Pyrenees. Our results show that the Iberian chain shared the same Early to Late Jurassic tectonothermal evolution with the Atlantic‐Alpine Tethyan rifted margins. From the Albian onward, the thermal evolution of the Cameros basin was very similar to that of the Pyrenees. This study shows that the preservation in mountain ranges of a succession of rifting events provide important clues for plate reconstructions.
Key Points
Iberian Range thermal history provides record of the tectonic evolution of the Iberia‐Europe plate boundary
Zircon grains cooled during rifting events are preserved in the Ebro basin detrital record
Diachronous Iberian Range and Pyrenean rifting events recorded the same Albian thermal anomaly and metamorphism
Depuis 2005, la perspective d’une identification électronique comme identification officielle des bovinsest reconnue par les pouvoirs publics et a effectivement abouti en 2011. Le projet avait comme ...objectifl’harmonisation des transferts de données collectées sur le terrain et associées au numéro électroniquelu et qui aboutissent dans un système d’information collectif (SIG, BDNI ou base sanitaire). Tous lesdomaines d’application éventuelle (insémination, IPG…) ont été étudiés, pour ne définir finalement desstandards d’échanges que pour les contrôles de performances lait et viande, pour lesquels celaapportait une utilité. Les échanges concernent les données en provenance ou à destination dessystèmes d’information collectifs : données de l’animal et lieu de détention dans un sens, mesures desperformances dans l’autre. Des propositions de standard de transfert de données utilisant l’identifiantofficiel électronique, ont été élaborées avec l’aide des fédérations professionnelles nationalesconcernées et des fabricants de matériels et de logiciels : données de pesées en vif, contrôle laitier parrobot de traite et compteurs à lait électroniques. La difficulté est de faire évoluer l’utilisation del’identification électronique intra troupeau (avec un numéro de travail de l’animal) par des systèmespropriétaires de chacun des fabricants, vers la lecture de la RFID officielle (numéro unique sur 15caractères, code pays + code national sur 12) et le transfert standard des données vers les bases dedonnées de l’éleveur et collectives. Seule cette valorisation de la RFID officielle permet l’amélioration dela fiabilité des données collectées et l’indépendance de l’éleveur vis à vis des fabricants de matériel etde logiciel. Plusieurs compétences, de l’automate de mesure aux logiciels cibles, en passant par lalecture électronique sur animaux vivants, sont concernées. Il est d’autant plus important de disposer destandards d’échanges entre ces différents partenaires présents dans tous les pays et pour toutes lesespèces (bovine, ovine, caprine, porcine). La mise en place d’une organisation capable de crédibiliser,de maintenir et de diffuser ce standard a été assurée : le représentant de l’Institut de l’Elevage porte lespropositions de standard pour validation et publication, d’une part au niveau national AFNOR et d’autrepart au niveau international, groupes de travail ISO ou ICAR concernés. Entre temps (2008 à 2010),des évolutions technologiques se sont développées. Le projet les a prises en compte : les capteurs dedonnées zootechniques pouvant servir à alerter l’éleveur sur des problèmes de santé, de reproductionou d’alimentation des animaux ; l’utilisation de repères UHF en complément éventuel de ceux en bassefréquence, choisie depuis 1996 pour le domaine animal et dont on connaît les limites.
Bovine electronic identification has been planned to be officially recognized since 2005 and it becomes effective in 2011. The aim of the project was the standardization of data collected in field and associated to the read electronic number and that are sent into common information system. All domains of possible application (insemination, traceability…) were studied and finally only data exchange standards for performance recording of suckled and dairy animals were defined because they proved to be useful.The data exchange concerns data from or to shared information systems: animal data and premises in one way, performances measures in the other way. Some data transfer standard propositions using the official electronic number, were created with the national professional federations concerned and with equipments and software manufacturers: weights of live animals, milk recording with robot, milk automate. The difficulty is that the use of the electronic farm work numbers with a private system for each manufacturer has to evolve towards the official RFID number on 15 digits (country code + national animal code on 12 digits) and to use standard data transfer to the external databases. Only this official RFID valorization allows the improvement of the collected data reliability and the farmer independence towards equipments and software manufacturers. Different specialized jobs are concerned: measurement automate, the reading of live animals and the software at all levels. It is important to have data exchange standards between these different stakeholders present in all countries and for any species (bovine, small ruminants). The setup of an organization able to maintain and widespread this standard is insured. The Institut de l’Elevage brings the standard propositions to be validated and published, at the national level AFNOR or at the international level in ISO or ICAR relevant working groups. During this project (2008 – 2010) technologic developments occurred and were taken into account in this project: sensors on animals collect data that can provide information to the farmer about health, reproduction event or food; UHF identifiers could be used in complement of the actual low frequency ones, standardized from 1996 and for which we know the limits and constraints.
To evaluate the relative contribution of different Magnetic Resonance Imaging (MRI) sequences for the extraction of radiomics features in a cohort of patients with lacrimal gland tumors. This ...prospective study was approved by the Institutional Review Board and signed informed consent was obtained from all participants. From December 2015 to April 2017, 37 patients with lacrimal gland lesions underwent MRI before surgery, including axial T1-WI, axial Diffusion-WI, coronal DIXON-T2-WI and coronal post-contrast DIXON-T1-WI. Two readers manually delineated both lacrimal glands to assess inter-observer reproducibility, and one reader performed two successive delineations to assess intra-observer reproducibility. Radiomics features were extracted using an in-house software to calculate 85 features per region-of-interest (510 features/patient). Reproducible features were defined as features presenting both an intra-class correlation coefficient ≥0.8 and a concordance correlation coefficient ≥0.9 across combinations of the three delineations. Among these features, the ones yielding redundant information were identified as clusters using hierarchical clustering based on the Spearman correlation coefficient. All the MR sequences provided reproducible radiomics features (range 14(16%)-37(44%)) and non-redundant clusters (range 5-14). The highest numbers of features and clusters were provided by the water and in-phase DIXON T2-WI and water and in-phase post-contrast DIXON T1-WI (37, 26, 26 and 26 features and 14,12, 9 and 11 clusters, respectively). A total of 145 reproducible features grouped into 51 independent clusters was provided by pooling all the MR sequences. All MRI sequences provided reproducible radiomics features yielding independent information which could potentially serve as biomarkers.
Abstract
Background
Succinate is produced by both human cells and by gut bacteria and couples metabolism to inflammation as an extracellular signaling transducer. Circulating succinate is elevated in ...patients with obesity and type 2 diabetes and is linked to numerous complications, yet no studies have specifically addressed the contribution of gut microbiota to systemic succinate or explored the consequences of reducing intestinal succinate levels in this setting.
Results
Using germ-free and microbiota-depleted mouse models, we show that the gut microbiota is a significant source of circulating succinate, which is elevated in obesity. We also show in vivo that therapeutic treatments with selected bacteria diminish the levels of circulating succinate in obese mice. Specifically, we demonstrate that
Odoribacter laneus
is a promising probiotic based on its ability to deplete succinate and improve glucose tolerance and the inflammatory profile in two independent models of obesity (
db/db
mice and diet-induced obese mice). Mechanistically, this is partly mediated by the succinate receptor 1. Supporting these preclinical findings, we demonstrate an inverse correlation between plasma and fecal levels of succinate in a cohort of patients with severe obesity. We also show that plasma succinate, which is associated with several components of metabolic syndrome including waist circumference, triglycerides, and uric acid, among others, is a primary determinant of insulin sensitivity evaluated by the euglycemic-hyperinsulinemic clamp.
Conclusions
Overall, our work uncovers
O. laneus
as a promising next-generation probiotic to deplete succinate and improve glucose tolerance and obesity-related inflammation.
Abstract Background Thermal ablation is a widely used minimally invasive treatment modality for different cancers. However, lack of a real-time imaging system for accurate evaluation of the procedure ...is one of the reasons of local recurrences. Shear waves elastography (SWE) is a new ultrasound (US) imaging modality to quantify tissue stiffness. The aim of the study was to assess the feasibility and accuracy of US elastography for quantitative monitoring of thermal ablation and to determine the elasticity threshold predictive of coagulation necrosis. Methods A total of 29 in vivo thermal lesions were performed in pig livers with radiofrequency system. SWE and B-mode images were acquired simultaneously. Liver elasticity was quantified by using SWE data and expressed in kilopascal. After the procedure, pathologic analysis of treated tissues was compared with US images. The sensitivity and positive predictive value of the SWE maps of tissue elasticity were calculated and compared with the boundaries of the pale coagulation necrosis areas found at pathology. Results The liver mean elasticity values before and after thermal therapy were 6.4 ± 0.3 and 38.1 ± 2.5 kPa, respectively ( P < 0.0001). For a threshold of 20 kPa, sensitivity (i.e., the rate of pixels correctly detected as necrosed tissue) was 0.8, and the positive predictive value (i.e., the rate of pixels in the elastographic map >20 kPa that actually developed coagulation necrosis) was 0.83. Conclusions Tissue areas with coagulation necrosis are significantly stiffer than the surrounding tissue. SWE permits the real-time detection of coagulation necrosis produced by radiofrequency and could potentially be used to monitor US-guided thermal ablation.
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