Identifying eroded Messinian deposits on the Maltese Islands by gypsum Sr isotopes

International audienceEvaporite sediments are known to have formed during the Messinian high salinity crisis that has been recognized in many Mediterranean areas. This event was however never identified on the Maltese Islands. In this study, a Sr isotopic characterization of gypsum, found as secondary minerals in the Oligocene-Miocene formations of Malta and Gozo is performed. The 87Sr/86Sr values are discussed on the basis of comparison with the surrounding rock Sr isotopic signature. The data outline two distinguishable 87Sr/86Sr ratios for gypsum according to their facies. Most of crack-infilling mineral data suggest a downward fluid circulation in the Miocene sediment associated with interaction in the currently outcropping limestones. Some gypsum crystals found as crystallized spherules show significantly lower 87Sr/86Sr ratios, close to those defined in the literature for Messinian evaporate sediments. Taken together, this may suggest that an evaporate formation of Messinian age had in the past covered the present-day sedimentary sequence in Malta and Gozo

En bloc resection of non-small cell lung cancer invading the thoracic inlet and intervertebral foramina

AbstractObjective: In patients with non-small cell lung cancer invading the thoracic inlet, the transcervical approach does not permit removal of tumor in the intervertebral foramina. We report a variant that lifts this limitation. Methods: Through the transcervical approach, resectability was assessed and tumor-bearing structures were removed, leaving tumor-free margins. Standard upper lobectomy was performed, leaving the lobe in place. A posterior midline approach was used for multilevel unilateral laminectomy, nerve root division inside the spinal canal, and vertebral body division along the midline. The tumor was removed en bloc with the lung, ribs, and vessels through the posterior incision. Fixation of the spine was performed. Medical charts of patients treated with this technique between October 1994 and April 2001 were reviewed retrospectively. Results: Seventeen patients (mean age 45 years) were treated. Resection of the upper lobe and T1 root was done in all 17 cases; 3- and 4-level hemivertebrectomies were done in 13 and 3 cases, respectively; 2-level total vertebral body resection and 2-level hemivertebrectomy were done in 1 case; and resections of the phrenic nerve and subclavian artery were done in 7 and 6 patients, respectively. There were no perioperative deaths or residual neurologic impairments. Postoperative complications were pneumonia (n = 6), cerebrospinal fluid leakage (n = 1), wound breakdown (n = 1), and bleeding necessitating reoperation (n = 1). The overall 3- and 5-year survivals were 39% and 20%, respectively. Conclusions: Non-small cell lung cancers invading the thoracic inlet and intervertebral foramina can be removed completely through a combined anterior transcervical and posterior midline approach, with good results.J Thorac Cardiovasc Surg 2002;123:676-8

A new look at old debates about the Corbières (NE-Pyrenees) geology: salt tectonics and gravity gliding

In the Corbières area, a large-scale nappe has been identified at the beginning of the 20th century: the “Nappe des Corbières Orientales” (NCO) resting over a thick Triassic sole. This geological object is located at the NE of the Pyrenees, close to the Gulf of Lions. At this place, the chain changes in orientation from E-W to NE-SW and presents in detail, a great complexity. The existence of the nappe itself has never been contested. However, due to its overall complexity, several controversies exist regarding the style and chronology of deformation of its substratum in the so-called the “Pinède de Durban” in particular. We show that the new concepts of salt tectonics can clarify these old debates. Indeed, the rise of the Triassic salt during Mesozoic rifting episodes results in the development of characteristic sedimentary sequences (halokinetic sequences) on top of salt walls. It is along one of these, coinciding with the prolongation of the Cévenole Fault System, that the NCO has been individualized. During its Cenozoic emplacement, a gravity-gliding component, explaining the importance of the observed translation, could result from an uplift preceding the rifting at the origin of the Gulf of Lions

Heat warnings in Switzerland: reassessing the choice of the current heat stress index

High temperatures lead to heat-related human stress and an increased mortality risk. To quantify heat discomfort and the relevant dangers, heat stress indices combine different meteorological variables such as temperature, relative humidity, radiation and wind speed. In this paper, a set of widely-used heat stress indices is analyzed and compared to the heat index currently used to issue official heat warnings in Switzerland, considering 28 Swiss weather stations for the years 1981?2017. We investigate how well warnings based on the heat index match warning days and warning periods that are calculated from alternative heat stress indices. The latter might allow for more flexibility in terms of specific warning demands and impact-based warnings. It is shown that the percentage of alternative warnings that match the official warnings varies among indices. Considering the heat index as reference, the simplified wet bulb globe temperature performs well and has some further advantages such as no lower bound and allowing for the calculation of climatological values. Yet, other indices (e.g., with higher dependencies on humidity) can have some added value, too. Thus, regardless of the performance in terms of matches, the optimal index to use strongly depends on the purpose of the warningAna Casanueva was funded by the HEAT-SHIELD Project (HORIZON 2020, research and innovation program under the grant agreement 668786)

Evidence for surface uplift of the Atlas Mountains and the surrounding peripheral plateaux: Combining apatite fission-track results and geomorphic indicators in the Western Moroccan Meseta (coastal Variscan Paleozoic basement)

This work represents an initial attempt to link the evolution of the topography in relation to the general tectonic framework of western Morocco. For this purpose, in a section of the Western Moroccan Meseta different tools are combined in order to attain the general objective. Apatite fission-track (AFT) data of granitic rocks of the Rabat–Khenifra area give ages around 200 Ma with track length distributions which are compatible with the thermal models already established for the area. An inverse correlation between AFT ages and elevation is observed which is compatible with previous models indicating northward tilting of the whole Western Moroccan Meseta which is younger than 20–25 Ma. In order to test this possibility a detailed analysis of the topography at different scales in the Western Moroccan Meseta has been performed. Results indicate that two open folds with different amplitudes are recognized and that the one with wider wavelength could correspond to a lithospheric fold as previously stated by other authors on the basis of independent geological arguments. The northward tilting proposed based on the AFT data agrees with the results obtained in the analysis of the topography which reinforces the presence of a very open fold with a wavelength of 200–300 km in the north-western limb of the Western Moroccan Meseta

A model-strengthened imaging biomarker for survival prediction in EGFR-mutated non-small-cell lung carcinoma patients treated with tyrosine kinase inhibitors

International audienceNon-small-cell lung carcinoma is a frequent type of lung cancer with a bad prognosis. Depending on the stage, genomics, several therapeutical approaches are used. Tyrosine Kinase Inhibitors (TKI) may be successful for a time in the treatment of EGFR-mutated non-small cells lung carcinoma. Our objective is here to propose a survival assessment as their efficacy in the long run is challenging to evaluate. The study includes 17 patients diagnosed as of EGFR-mutated non-small cell lung cancer and exposed to an EGFR-targeting TKI with 3 computed tomography (CT) scans of the primitive tumor (one before the TKI introduction and two after). An imaging biomarker based on the texture heterogeneity evolution between the first and the third exams is derived and computed from a mathematical model and patient data. Defining the overall survival as the time between the introduction of the TKI treatment and the patient death, we obtain a statistically significant correlation between the overall survival and our imaging marker (p = 0:009). Using the ROC curve, the patients are separated into two populations and the comparison of the survival curves is statistically significant (p = 0:025). The baseline exam seems to have a significant role in the prediction of response to TKI treatment. More precisely, our imaging biomarker defined using only the CT scan before the TKI introduction allows to determine a first classification of the population which is improved over time using the imaging marker as soon as more CT scans are available. This exploratory study leads us to think that it is possible to obtain a survival assessment using only few CT scans of the primary tumor

Effects of fatigue on trunk stability in elite gymnasts

The aim of the present study was to test the hypothesis that fatigue due to exercises performed in training leads to a decrement of trunk stability in elite, female gymnasts. Nine female gymnasts participated in the study. To fatigue trunk muscles, four series of five dump handstands on the uneven bar were performed. Before and after the fatigue protocol, participants performed three trials of a balancing task while sitting on a seat fixed over a hemisphere to create an unstable surface. A force plate tracked the location of the center of pressure (CoP). In addition, nine trials were performed in which the seat was backward inclined over a set angle and suddenly released after which the subject had to regain balance. Sway amplitude and frequency in unperturbed sitting were determined from the CoP time series and averaged over trials. The maximum displacement and rate of recovery of the CoP location after the sudden release were determined and averaged over trials. After the fatigue protocol, sway amplitude in the fore-aft direction was significantly increased (p = 0.03), while sway frequency was decreased (p = 0.005). In addition, the maximum displacement after the sudden release was increased (p = 0.009), while the rate of recovery after the perturbation was decreased (p = 0.05). Fatigue induced by series of exercises representing a realistic training load caused a measurable decrement in dynamic stability of the trunk in elite gymnasts

Helium trapping in apatite damage: insights from (U-Th-Sm)/He dating of different granitoid lithologies

Apatite (U-Th-Sm)/He (AHe) thermochronometry is widely used to constrain thermal histories and rates of tectonic, exhumation, and erosion processes. However, data interpretation is often challenging, especially when the thermal history includes extended residence time in the He partial retention zone (HePRZ), with highly dispersed dates revealing the complexity of diffusion processes in natural systems. This study investigates chemical and physical factors that may have impacted He diffusion in apatite over long timescales in a context of protracted residence in the HePRZ. Nine samples from the Ploumanac'h pluton and North Tregor (Armorican Massif, France) were collected in granitoids, differing in petrography and chemisty. This area was chosen because these samples underwent a similar thermal history since ~300 Ma. We report new (U-Th Sm)/He dates, along with apatite fission-track (AFT) data, as well as lithological and chemical characterization. The results show dispersed (U-Th-Sm)/He dates, ranging from 87 ± 7 to 291 ± 23 Ma, whereas central AFT dates vary from 142 ± 6 to 199 ± 9 Ma. Current predictive models for He diffusion and fission-track annealing in apatite could not reproduce the two datasets together. However, this apparent discrepancy gives insight into the parameters influencing He diffusion at geological timescales. The data confirm that radiation damage enhances He trapping, as the AHe dates are positively correlated to effective uranium (eU) concentration. The He age dispersion for constant eU content cannot be explained just by variations in grain size or chemical composition. To explore the potential influence of recoil damage trapping behavior and annealing kinetics on AHe dates, we tested a new diffusion model from Gerin et al. (2017). Given the expected model of the thermal history provided by AFT inversion, we investigated the influence of the trapping energy on AHe dates. The AHe date variations can be explained only if the trapping energy evolves from one crystal to another, increasing with the amount of damage. For a given trapping energy, minor variations in the recoil-damage annealing rate can consistently explain most of the remaining dispersion of the AHe dates