Modélisation numérique de la minéralisation polymétallifère du gisement de Tighza (Maroc central) par l’outil SIG et la géostatistique

Le gisement de Tighza est le 1er site producteur de concentré de plomb et le 2nd fournisseur d’argent au Maroc. Sa durée de vie s’étale sur 15 ans .en effet, la Compagnie minière de Touissit (CMT) a réalisé, en 2008, un chiffre d'affaires de 291,4 MMDH contre 247,3 en 2007, soit une progression de plus 17%. Cette augmentation est due, entre autres, à l'évolution positive des tonnages vendus (plomb +14,3%, zinc +48,9%). Pour les opérateurs miniers, la viabilité du site est capitale. Les recherches menées actuellement visent à prolonger la durée d’exploitation du gisement de Tighza. Ces recherches pose, au sein de la Compagnie Minière de Touissit (CMT), un problème d’organisation et de stockage de l’information produite par ses différents services notamment celui de la géologie. Face à cette situation, et compte tenu du volume de données produit, qui ne cesse de s’accroître d’une part, et leur éventuelle perte d’autre part, la CMT a décidé d’instaurer un système d’information, à travers une base de données numérisée, lui permettant le stockage, le traitement et l’exploitation rationnelle de l’information disponible en vue d’aider les responsables miniers à prendre les décisions qui conviennent. Dans ce sens, nous avons utilisé l’environnement ArcGIS pour mettre en place une base de données spatiales par la numérisation, le  géoréférencement et l’élaboration d’un certain nombre de couches d’informations à partir de cartes topographique, géologique, géochimique et les données de sondages carottés. Ainsi un Modèle Numériquede Terrain (MNT) du secteur de Tighza a été élaboré en se basant sur les courbes de niveau et des points côtés digitalisés à partir de la carte topographique. Ce travail est complété par un traitement statistique et géostatistique. Ainsi une analyse multidimensionnelle utilisant l’analyse en composante principale (ACP) a permis de déterminer les principaux axes factoriels. Le traitement géostatistique des données géochimiques a consisté d’abord à une modélisation des variogrammes des différents éléments chimiques, l’élaboration des cartes variographiques et enfin l’établissement des cartes de répartition spatiale par krigeage pour chaqueélément. Les cartes thématiques obtenues pouvant conduire à l’élaboration d’un modèle géochimique renseignant sur la répartition des métaux de ce district.Mots clés : SIG, cartographie, géologie minière, statistique, géostatistique, Tighza, Maroc Central

Slope Stability of Embankments on Soft Soil Improved with Vertical Drains

The overloads of structures or embankments built on clayey soft ground are generally applied gradually, respecting a specific phasing. This phasing on construction allows the undrained shear strength of clay increasing over consolidation in order to avoid the risk of collapse during loading. In this work, the undrained shear strength of clay over the consolidation was estimated following SHANSEP method of which parameters proposed by eight researchers have been employed, as well as the slope stability analysis of embankments on soft soils during staged construction. Assessment of factor of safety for slope stability was conducted basing on the Bishop method. Additionally, the variations of undrained shear strength and factor of safety were presented. In order to validate the methods discussed in this study, slope stability analysis of five embankments constructed on clayey soft soils improved by the vertical drain technique in a high-speed railway construction project in Morocco was performed. For these embankments, field measurements about lateral displacement are presented.  It was found that some of the adopted methods is in a good agreement with field measurements. Hence, generalization of these methods to many soft ground cases can be proposed

Significant reduction in heart rate variability is a feature of acute decompensation of cirrhosis and predicts 90-day mortality

Background: Heart rate variability (HRV) is reduced in cirrhosis and in conditions of systemic inflammation. Whether HRV is associated with cirrhosis decompensation and development of acute‐on‐chronic liver failure (ACLF) is unknown. // Aims: To (a) validate wireless remote HRV monitoring in cirrhosis decompensation; (b) determine if severely reduced HRV is a surrogate for inflammation and progression of cirrhosis decompensation; (c) assess if measuring HRV determines prognosis in cirrhosis decompensation. // Methods: One hundred and eleven patients at risk of cirrhosis decompensation at two clinical sites were monitored for HRV. Standard deviation of all normal beat‐beat intervals (SDNN) reflecting HRV was assessed using remote monitoring (Isansys Lifetouch) and/or Holter ECG recording. Clinical outcomes and major prognostic scores were recorded during 90‐day follow‐up. // Results: Reduced HRV denoted by lower baseline SDNN, correlated with severity of decompensation (median 14 (IQR 11‐23) vs 33 (25‐42); P < 0.001, decompensated patients vs stable outpatient cirrhosis). Furthermore, SDNN was significantly lower in patients developing ACLF compared to those with only decompensation (median 10 (IQR9‐12) vs 16 (11‐24); P = 0.02), and correlated inversely with MELD and Child‐Pugh scores, and C‐reactive protein (all P < 0.0001) and white cell count (P < 0.001). SDNN predicted disease progression on repeat measures and appeared an independent predictor of 90‐day mortality (12 patients). An SDNN cut‐off of 13.25 ms had a 98% negative predictive value. // Conclusions: This study demonstrates that remote wireless HRV monitoring identifies cirrhosis patients at high risk of developing ACLF and death, and suggests such monitoring might guide the need for early intervention in such patients. Clinical Trial number: NIHR clinical research network CPMS ID 4949

Water Erosion Monitoring and Prediction in Response to the Effects of Climate Change Using RUSLE and SWAT Equations: Case of R’Dom Watershed in Morocco

Soil erosion is an increasingly issue worldwide, due to several factors including climate variations and humans’ activities, especially in Mediterranean ecosystems. Therefore, the aim of this paper is: (i) to quantify and to predict soil erosion rate for the baseline period (2000–2013) and a future period (2014–2027), using the Revised Universal Soil Loss Equation (RUSLE) and the Soil and Water Assessment Tool (SWAT) model in the R’Dom watershed in Morocco, based on the opportunities of Remote Sensing (RS) techniques and Geographical Information System (GIS) geospatial tools. (ii) we based on classical statistical downscaling model (SDSM) for rainfall prediction. Due to the lack of field data, the model results are validated by expert knowledge. As a result of this study, it is found that both agricultural lands and bare lands are most affected by soil erosion. Moreover, it is showed that soil erosion in the watershed was dominated by very low and low erosion. Although the area of very low erosion and low erosion continued to decrease. Hence, we hereby envisage that our contribution will provide a more complete understanding of the soil degradation in this study area and the results of this research could be a crucial reference in soil erosion studies and also may serve as a valuable guidance for watershed management strategies

QUANTITATIVE ASSESSMENT OF ACUTE REGURGITATION FOLLOWING TRANSCATHETER AORTIC VALVE IMPLANTATION: A MULTICENTER POOLED ANALYSIS OF 2,258 VALVES

Objectives: The aim of this study was to assess acute regurgitation following transcatheter aortic valve replacement, comparing different implanted transcatheter heart valves. Background: Regurgitation following transcatheter aortic valve replacement influences all-cause mortality. Thus far, no quantitative comparison of regurgitation among multiple commercially available transcatheter heart valves has been performed. Methods: Aortograms from a multicenter cohort of consecutive 3,976 transcatheter aortic valve replacements were evaluated in this pooled analysis. A total of 2,258 (58.3%) were considered analyzable by an independent academic core laboratory using video densitometry. Results of quantitative regurgitation are shown as percentages. The valves evaluated were the ACURATE (n = 115), Centera (n = 11), CoreValve (n = 532), Direct Flow Medical (n = 21), Evolut PRO (n = 95), Evolut R (n = 295), Inovare (n = 4), Lotus (n = 546), Lotus Edge (n = 3), SAPIEN XT (n = 239), and SAPIEN 3 (n = 397). For the main analysis, only valves with more than 50 procedures (7 types) were used. Results: The Lotus valve had the lowest mean regurgitation (3.5 \ub1 4.4%), followed by Evolut PRO (7.4 \ub1 6.5%), SAPIEN 3 (7.6 \ub1 7.1%), Evolut R (7.9 \ub1 7.4%), SAPIEN XT (8.8 \ub1 7.5%), ACURATE (9.6 \ub1 9.2%) and CoreValve (13.7 \ub1 10.7%) (analysis of variance p &lt; 0.001). The only valves that statistically differed from all their counterparts were Lotus (as the lowest regurgitation) and CoreValve (the highest). The proportion of patients presenting with moderate or severe regurgitation followed the same ranking order: Lotus (2.2%), Evolut PRO (5.3%), SAPIEN 3 (8.3%), Evolut R (8.8%), SAPIEN XT (10.9%), ACURATE (11.3%), and CoreValve (30.1%) (chi-square p &lt; 0.001). Conclusions: In this pooled analysis stemming from daily clinical practice, the Lotus valve was shown to have the best immediate sealing. This analysis reflects the objective evaluation of regurgitation by an academic core laboratory (nonsponsored) in a real-world cohort of patients using a quantitative technique

Elucidation of the genetic causes of bicuspid aortic valve disease.

AIMS The present study aims to characterize the genetic risk architecture of bicuspid aortic valve (BAV) disease, the most common congenital heart defect. METHODS AND RESULTS We carried out a genome-wide association study (GWAS) including 2236 BAV patients and 11 604 controls. This led to the identification of a new risk locus for BAV on chromosome 3q29. The single nucleotide polymorphism rs2550262 was genome-wide significant BAV associated (P = 3.49 × 10-08) and was replicated in an independent case-control sample. The risk locus encodes a deleterious missense variant in MUC4 (p.Ala4821Ser), a gene that is involved in epithelial-to-mesenchymal transformation. Mechanistical studies in zebrafish revealed that loss of Muc4 led to a delay in cardiac valvular development suggesting that loss of MUC4 may also play a role in aortic valve malformation. The GWAS also confirmed previously reported BAV risk loci at PALMD (P = 3.97 × 10-16), GATA4 (P = 1.61 × 10-09), and TEX41 (P = 7.68 × 10-04). In addition, the genetic BAV architecture was examined beyond the single-marker level revealing that a substantial fraction of BAV heritability is polygenic and ∼20% of the observed heritability can be explained by our GWAS data. Furthermore, we used the largest human single-cell atlas for foetal gene expression and show that the transcriptome profile in endothelial cells is a major source contributing to BAV pathology. CONCLUSION Our study provides a deeper understanding of the genetic risk architecture of BAV formation on the single marker and polygenic level