41 research outputs found

    Microstructural finite strain analysis of the Hafafit granitoids domes South Central Eastern desert of Egypt

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    The Wadi Hafafit Culmination (WHC) can be subdivided into two main units which are separated by Nugrus thrust shear zone. The WHC domes are occupies the southern part of the Central Eastern Desert of Egypt and is cored by five separated gneissic granitoids ranging in composition from tonalite to granodiorite having compositions consistent with hydrous partial melting of a mafic source suggesting subduction-related magmatism. The leucogranites along thrust zones is related to the late phase of metamorphism of Hafafit rocks. The five main domes of the WHC have been labeled A dome occupies the northern part of WHC, B and C domes occupies the central eastern part of WHC, D dome occupies the central western part of WHC and E dome occupies the southern part of WHC. The fourth domes A, B, C and E are affected by more than one deformation event but D dome is affected by one deformation event. The domes not uniform throughout the WHC according radial pattern of stretching lineation but these domes of WHC were subjected and affected by late-orogenic extension that was controlled by the Najd transform faults and that resulted in exhumation of the WHC domes are oriented NW-SE parallel to the trend of the left-lateral shear zones of Najd fault system

    A probabilistic method for the operation of three-phase unbalanced active distribution networks

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    YesThis paper proposes a probabilistic multi-objective optimization method for the operation of three-phase distribution networks incorporating active network management (ANM) schemes including coordinated voltage control and adaptive power factor control. The proposed probabilistic method incorporates detailed modelling of three-phase distribution network components and considers different operational objectives. The method simultaneously minimizes the total energy losses of the lines from the point of view of distribution network operators (DNOs) and maximizes the energy generated by photovoltaic (PV) cells considering ANM schemes and network constraints. Uncertainties related to intermittent generation of PVs and load demands are modelled by probability density functions (PDFs). Monte Carlo simulation method is employed to use the generated PDFs. The problem is solved using ɛ-constraint approach and fuzzy satisfying method is used to select the best solution from the Pareto optimal set. The effectiveness of the proposed probabilistic method is demonstrated with IEEE 13- and 34- bus test feeders

    Influence of root and leaf traits on the uptake of nutrients in cover crops

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    Aims: Cover crops play an important role in soil fertility as they can accumulate large amounts of nutrients. This study aimed at understanding the nutrient uptake capacity of a wide range of cover crops and at assessing the relevance of acquisition strategies. Methods: A field experiment was conducted to characterize 20 species in terms of leaf and root traits. Plant traits were related to nutrient concentration and shoot biomass production with a redundancy analysis. Acquisition strategies were identified using a cluster analysis. Results: Root systems varied greatly among cover crop species. Five nutrient acquisition strategies were delineated. Significant amounts of nutrients (about 120 kg ha−1 of nitrogen, 30 kg ha−1 of phosphorus and 190 kg ha−1 of potassium) were accumulated by the species in a short period. Nutrient acquisition strategies related to high accumulations of nutrients consisted in either high shoot biomass and root mass and dense tissues, or high nutrient concentrations and root length densities. Species with high root length densities showed lower C/N ratios. Conclusions: The same amounts of nutrients were accumulated by groups with different acquisition strategies. However, their nutrient concentrations offer different perspectives in terms of nutrient release for the subsequent crop and nutrient cycling improvement

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    How Does Education Improve Cognitive Skills? Instructional Time versus Timing of Instruction

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    This paper investigates two mechanisms through which education may affect cognitive skills in adolescence: the role of instructional quantity and the timing of instruction with respect to age. To identify causal effects, I exploit a school reform carried out at the state level in Germany as a quasi-natural experiment: between 2001 and 2007, academic-track high school (Gymnasium) was reduced by one year in most of Germany's federal states, leaving the overall curriculum unchanged. To investigate the impact of this educational change on students' cognitive abilities, I conduct two separate analyses: first, I exploit the variation in the curriculum taught to same-aged students at academic-track high school over time and across states to identify the effect of the increase in instructional time on students' crystallized and fluid intelligence scores. Using rich data on seventeen year-old adolescents from the German Socio-Economic Panel (SOEP) study, the estimates show that fluid intelligence remained unaffected, while crystallized intelligence improved for male students. Second, I compare students' competences in their final year of high school using data from the German National Educational Panel Study (NEPS). Preliminary results suggest that students affected by the reform catch up with their non-affected counterparts in terms of their competences by the time of graduation. However, they do not provide any evidence for the timing of instruction to matter in cognitive skill formation. Overall, secondary education therefore seems to impact students' cognitive skills in adolescence especially through instructional time and not so much through age-distinct timing of instruction

    Crustal Structure of the Nile Delta: Interpretation of Seismic-Constrained Satellite-Based Gravity Data

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    Interpretations of the tectonic setting of the Nile Delta of Egypt and its offshore extension are challenged by the thick sedimentary cover that conceals the underlying structures and by the paucity of deep seismic data and boreholes. A crustal thickness model, constrained by available seismic and geological data, was constructed for the Nile Delta by inversion of satellite gravity data (GOCO06s), and a two-dimensional (2D) forward density model was generated along the Delta’s entire length. Modelling results reveal the following: (1) the Nile Delta is formed of two distinctive crustal units: the Southern Delta Block (SDB) and the Northern Delta Basin (NDB) separated by a hinge zone, a feature widely reported from passive margin settings; (2) the SDB is characterized by an east–west-trending low-gravity (~−40 mGal) anomaly indicative of continental crust characteristics (depth to Moho (DTM): 36–38 km); (3) the NDB and its offshore extension are characterized by high gravity anomalies (hinge zone: ~10 mGal; Delta shore line: >40 mGal; south Herodotus Basin: ~140 mGal) that are here attributed to crustal thinning and stretching and decrease in DTM, which is ~35 km at the hinge zone, 30–32 km at the shoreline, and 22–20 km south of the Herodotus Basin; and (4) an apparent continuation of the east-northeast–west-southwest transitional crust of the Nile Delta towards the north-northeast–south-southwest-trending Levant margin in the east. These observations together with the reported extensional tectonics along the hinge zone, NDB and its offshore, the low to moderate seismic activity, and the absence of volcanic eruptions in the Nile Delta are all consistent with the NDB being a non-volcanic passive margin transition zone between the North African continental crust (SDB) and the Mediterranean oceanic crust (Herodotus Basin), with the NDB representing a westward extension of the Levant margin extensional transition zone
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