The Physical Characteristics of a CO2 Seeping Fault: the implications of fracture permeability for carbon capture and storage integrity

To ensure the effective long-term storage of CO2 in candidate geological storage sites, evaluation of potential leakage pathways to the surface should be undertaken. Here we use a series of natural CO2 seeps along a fault in South Africa to assess the controls on CO2 leakage to the surface. Geological mapping and detailed photogrammetry reveals extensive fracturing along the mapped fault trace. Measurements of gas flux and CO2 concentration across the fracture corridor give maximum soil gas measurements of 27% CO2 concentration and a flux of 191 g m−2 d−1. These measurements along with observations of gas bubbles in streams and travertine cones attest to CO2 migration to the surface. Permeability measurements on the host rock units show that the tillite should act as an impermeable seal to upward CO2 migration. The combined permeability and fracture mapping data indicate that fracture permeability creates the likely pathway for CO2 migration through the low permeability tillite to the surface. Heterogeneity in fracture connectivity and intensity at a range of scales will create local higher permeability pathways along the fracture corridor, although these may seal with time due to fluid-rock interaction. The results have implications for the assessment and choice of geological CO2 storage sites, particularly in the assessment of sub-seismic fracture networks

Along-strike fault core thickness variations of a fault in poorly lithified sediments, Miri (Malaysia)

Fault resistance to across-fault fluid flow is as strong as its weakest point. Processes that determine patches of the fault surface containing transmissible fault rocks must be taken into account to produce reliable predictions of cross fault fluid flow. We use a study site in Miri as a natural laboratory to investigate in detail the fault core thickness variations along-strike and down dip and to quantify the risk of discontinuities in the clay-rich fault core. Five fault core types have been identified: foliated clay-rich fault core, chaotic clay-rich fault core, attenuated clay-rich fault core, sandy anastomosing shears and sandy breccia. The sandy fault rocks are likely to have lower capillary entry pressure, and higher permeability than the clay-rich rock, so could represent potential cross-fault flow pathways. We performed a geostatistical analysis, showing a correlation over 3 m scale, suggesting the presence of ‘patches’ of thin and thick fault core generally less than 3m in length. We interpret this as superimposition of two (or more) different deformation processes at a smaller and larger scale. We speculate on the processes that could produce the observed distribution of thickness and composition, in particular processes that could have disrupted the through-going clay-rich core

Intrinsic defects and mid-gap states in quasi-one-dimensional Indium Telluride

Recently, intriguing physical properties have been unraveled in anisotropic semiconductors, in which the in-plane electronic band structure anisotropy often originates from the low crystallographic symmetry. The atomic chain is the ultimate limit in material downscaling for electronics, a frontier for establishing an entirely new field of one-dimensional quantum materials. Electronic and structural properties of chain-like InTe are essential for better understanding of device applications such as thermoelectrics. Here, we use scanning tunneling microscopy/spectroscopy (STM/STS) measurements and density functional theory (DFT) calculations to directly image the in-plane structural anisotropy in tetragonal Indium Telluride (InTe). As results, we report the direct observation of one-dimensional In1+ chains in InTe. We demonstrate that InTe exhibits a band gap of about 0.40 +-0.02 eV located at the M point of the Brillouin zone. Additionally, line defects are observed in our sample, were attributed to In1+ chain vacancy along the c-axis, a general feature in many other TlSe-like compounds. Our STS and DFT results prove that the presence of In1+ induces localized gap state, located near the valence band maximum (VBM). This acceptor state is responsible for the high intrinsic p-type doping of InTe that we also confirm using angle-resolved photoemission spectroscopy.Comment: n

PIAF : développer la Pensée Informatique et Algorithmique dans l'enseignement Fondamental

Version étendue d'un article présenté au colloque Didapro8.Dans cet article, nous présentons les objectifs et premières réalisations du projet PIAF soutenu par l'Union Européenne et visant à développer l'apprentissage de la pensée informatique et algorithmique dans l'enseignement fondamental. Ce projet rassemble des chercheur·e·s en sciences de l'éducation et en informatique, provenant de quatre pays (Allemagne, Belgique, France et Luxembourg), autour du thème de la formation des enseignant·e·s. Plus concrètement, il s'agit de dénir un cadre (référentiel de compétences, scénarios pédagogiques) permettant aux enseignant·e·s de (i) s'approprier le concept de pensée informatique et algorithmique et de (ii) mettre en ÷uvre des activités d'apprentissage favorisant le développement de cette pensée chez l'enfant

Sex differences in outcome after carotid revascularization in symptomatic and asymptomatic carotid artery stenosis

Objective: Sex differences regarding the safety and efficacy of carotid revascularization in carotid artery stenosis have been addressed in several studies with conflicting results. Moreover, women are underrepresented in clinical trials leading to limited conclusions regarding the safety and efficacy of acute stroke treatments. Methods: A systematic review and meta-analysis was performed by literature search including 4 databases from January 1985 to December 2021. Sex differences in the efficacy and safety of revascularization procedures, including carotid endarterectomy (CEA) and carotid artery stenting (CAS), for symptomatic and asymptomatic carotid artery stenoses were analyzed. Results: Regarding carotid endarterectomy (CEA) in symptomatic carotid artery stenosis, the stroke risk in men (3.6%) and women (3.9%) based on 99,495 patients (30 studies) did not differ (p=0.16). There was also no difference in the stroke risk by different time frames up to 10 years. Compared with men, women treated with CEA had a significantly higher stroke or death rate at 4 months (2 studies, 2565; 7.2% vs 5.0%; OR 1.49, 95% CI 1.04-2.12; I2=0%; p=0.03), and a significantly higher rate of restenosis (1 study, 615; 17.2% vs. 6.7%; OR 2.81,95% CI 1.66-4.75; p=0.0001). For carotid stenting (CAS) in symptomatic artery stenosis data showed a non-significant tendency toward higher peri-procedural stroke in women. Whereas, for asymptomatic carotid artery stenosis, data based on 332,344 patients showed that women compared to men after CEA had similar rates of stroke, stroke or death and the composite outcome stroke/death/myocardial infarction. The rate of restenosis at 1 year was significantly higher in women compared to men (1 study, 372 patients; 10.8% vs 3.2%; OR 3.71, 95% CI 1.49-9.2; p=0.005). Furthermore, carotid stenting in asymptomatic patients was associated with low risk of a postprocedural stroke in both sexes, but a significantly higher risk of in-hospital myocardial infarction in women than men (8445 patients, 1.2% vs. 0.6%, OR 2.01, 95%CI 1.23-3.28, I2=0%, p=0.005). Conclusions: A few sex-differences in short term outcomes after carotid revascularization for symptomatic and asymptomatic carotid artery stenosis were found, although there were no significant differences in the overall stroke. This indicates a need for larger multicenter prospective studies to evaluate these sex-specific differences. More women, including those aged over 80 years, need to be enrolled in RCTs, to better understand if sex differences exist and to tailor carotid revascularization accordingly

PIAF : développer la Pensée Informatique et Algorithmique dans l'enseignement Fondamental

International audienceDans cet article, nous présentons les objectifs et premières réalisations du projet PIAF soutenu par l'Union Européenne et visant à développer l'apprentissage de la pensée informatique et algorithmique dans l'enseignement fondamental. Ce projet rassemble des chercheur·e·s en sciences de l'éducation et en informatique, provenant de quatre pays (Allemagne, Belgique, France et Luxembourg), autour du thème de la formation des enseignant·e·s. Plus concrètement, il s'agit de dénir un cadre (référentiel de compétences, scénarios pédagogiques) permettant aux enseignant·e·s de (i) s'approprier le concept de pensée informatique et algorithmique et de (ii) mettre en ÷uvre des activités d'apprentissage favorisant le développement de cette pensée chez l'enfant

PIAF : développer la Pensée Informatique et Algorithmique dans l'enseignement Fondamental

Version étendue d'un article présenté au colloque Didapro8.Dans cet article, nous présentons les objectifs et premières réalisations du projet PIAF soutenu par l'Union Européenne et visant à développer l'apprentissage de la pensée informatique et algorithmique dans l'enseignement fondamental. Ce projet rassemble des chercheur·e·s en sciences de l'éducation et en informatique, provenant de quatre pays (Allemagne, Belgique, France et Luxembourg), autour du thème de la formation des enseignant·e·s. Plus concrètement, il s'agit de dénir un cadre (référentiel de compétences, scénarios pédagogiques) permettant aux enseignant·e·s de (i) s'approprier le concept de pensée informatique et algorithmique et de (ii) mettre en ÷uvre des activités d'apprentissage favorisant le développement de cette pensée chez l'enfant

PIAF: Developing Computational and Algorithmic Thinking in Fundamental Education

Full text available at http://www.learntechlib.org/p/217317/International audienceIn this article, we present the objectives and first achievements of the PIAF project supported by the European Union and aiming at developing computational and algorithmic thinking in basic education. This project brings together researchers in educational sciences and computer science from four countries (Belgium, France, Germany and Luxembourg) around the theme of teacher training. More concretely, the aim is to define a framework (competency framework, pedagogical scenarios) enabling teachers to (i) appropriate the concept of computational and algorithmic thinking and (ii) implement learning activities that promote the development of this kind of thinking in children

PIAF : développer la Pensée Informatique et Algorithmique dans l'enseignement Fondamental

International audienceDans cet article, nous présentons les objectifs et premières réalisations du projet PIAF soutenu par l'Union Européenne et visant à développer l'apprentissage de la pensée informatique et algorithmique dans l'enseignement fondamental. Ce projet rassemble des chercheur·e·s en sciences de l'éducation et en informatique, provenant de quatre pays (Allemagne, Belgique, France et Luxembourg), autour du thème de la formation des enseignant·e·s. Plus concrètement, il s'agit de dénir un cadre (référentiel de compétences, scénarios pédagogiques) permettant aux enseignant·e·s de (i) s'approprier le concept de pensée informatique et algorithmique et de (ii) mettre en ÷uvre des activités d'apprentissage favorisant le développement de cette pensée chez l'enfant

European Stroke Organisation guidelines on stroke in women: Management of menopause, pregnancy and postpartum

Pregnancy, postpartum and menopause are regarded as periods women are more vulnerable to ischaemic events. There are conflicting results regarding stroke risk and hormone replacement therapy (HRT) during menopause. Stroke in pregnancy is generally increasing with serious consequences for mother and child; therefore, recommendations for acute treatment with intravenous thrombolysis (IVT) and/or mechanical thrombectomy (MT) are needed. The aim of this guideline is to support and guide clinicians in treatment decisions in stroke in women. Following the “Grading of Recommendations and Assessment, Development and Evaluation (GRADE)” approach, the guidelines were developed according to the European Stroke Organisation (ESO) Standard Operating Procedure. Systematic reviews and metanalyses were performed. Based on available evidence, recommendations were provided. Where there was a lack of evidence, an expert consensus statement was given. Low quality of evidence was found to suggest against the use of HRT to reduce the risk of stroke (ischaemic and haemorrhagic) in postmenopausal women. No data was available on the outcome of women with stroke when treated with HRT. No sufficient evidence was found to provide recommendations for treatment with IVT or MT during pregnancy, postpartum and menstruation. The majority of members suggested that pregnant women can be treated with IVT after assessing the benefit/risk profile on an individual basis, all members suggested treatment with IVT during postpartum and menstruation. All members suggested treatment with MT during pregnancy. The guidelines highlight the need to identify evidence for stroke prevention and acute treatment in women in more vulnerable periods of their lifetime to generate reliable data for future guidelines