Isotopic constraints on the age and source of ore-forming fluids of the Bou Azzer arsenide ores (Morocco)

The authors greatly acknowledge the geological survey of CTT-Bou Azzer mine for facilitating our geological field campaigns and specially to Clemente Recio (University of Salamanca) for his invaluable help to IS during the development of the analytical procedure to mea-sure S isotope compositions from the minor amounts of S extracted from arsenides and sulfarsenides. Authors would like to acknowledge the use of Servicio General de Apoyo a la Investigacion-SAI, Universidad de Zaragoza. This research was financially supported by the Spanish project RTI2018-099157-A-I00 granted by the "Ministerio de Ciencia, Innovacion y Universidades". The Swedish Research Council (infra-structure grant: Dnr. 2017-00671) is thanked for financial support to the Vegacenter national laboratory. This is Vegacenter publication number 124The Bou Azzer district in Morocco has a long mining history since the beginning of the XXst century during which it has become the only world producer of Co from primary, hydrothermal Co arsenide ores. Orebodies are structurally controlled, and mainly distributed along fault contacts between Cryogenian ophiolite-related serpentinite bodies and intrusive quartz diorite or, locally, ophiolitic gabbros or Ediacaran volcanic rocks. Ore formation took place through a multi-stage mineralizing process that included an early stage composed by gold, quartz, chlorite, muscovite and calcite, followed by the main arsenide and sulfarsenide stage (subdivided into three substages, IIa: Ni-rich, Co ores, IIb: Co-Fe ores and IIc: Fe-Co ores), and ending with an epithermal stage characterized by the precipitation of sulfides along with quartz and calcite. Field relations and most previous geochronologic dating pointed to a post Pan-African age of ore formation, mainly coincident with the Hercynian orogeny. The isotopic study presented in this paper includes S, Pb, Rb/Sr and Sm/Nd data of a set of ore mineral samples from three deposits (Aghbar, Tamdrost and Aït Ahmane), as well as of regional samples representative of the different lithologies occurring in the Bou Azzer area. The isotope data set was completed with S isotope analyses of arsenide and sulfarsenide minerals from five ore deposits (Filon 7/5, Aghbar, Tamdrost, Ightem and Aït- Ahmane) and of some whole-rock regional samples. Results show that ores formed during multi-episodic hydrothermal events connected with hercynian reactivation of Devonian-Carboniferous faults, supporting previous geochronologic dating. The obtained Pb, Sr, Nd and S isotopic signatures of ore minerals and regional rocks further show that ophiolite-related lithologies became isotopically modified by interaction with crustal material and afterwards acted as the main source of ore-forming elements. Nevertheless, isotopic data do not fully concur with such a simple scenario but are quite consistent with a rather complex interpretation based on multi-source origin of some elements and isotopes scavenged from a number of isotopically different lithologies both from the inferred basement and the volcanic and sedimentary cover.Spanish Government RTI2018-099157-A-I00Swedish Research Council European Commission Dnr. 2017-0067

Isotopic constraints on the age and source of ore-forming fluids of the Bou Azzer arsenide ores (Morocco)

The Bou Azzer district in Morocco has a long mining history since the beginning of the XXst century during which it has become the only world producer of Co from primary, hydrothermal Co arsenide ores. Orebodies are structurally controlled, and mainly distributed along fault contacts between Cryogenian ophiolite-related serpentinite bodies and intrusive quartz diorite or, locally, ophiolitic gabbros or Ediacaran volcanic rocks. Ore formation took place through a multi-stage mineralizing process that included an early stage composed by gold, quartz, chlorite, muscovite and calcite, followed by the main arsenide and sulfarsenide stage (subdivided into three substages, IIa: Ni-rich, Co ores, IIb: Co-Fe ores and IIc: Fe-Co ores), and ending with an epithermal stage characterized by the precipitation of sulfides along with quartz and calcite. Field relations and most previous geochronologic dating pointed to a post Pan-African age of ore formation, mainly coincident with the Hercynian orogeny. The isotopic study presented in this paper includes S, Pb, Rb/Sr and Sm/Nd data of a set of ore mineral samples from three deposits (Aghbar, Tamdrost and Aït Ahmane), as well as of regional samples representative of the different lithologies occurring in the Bou Azzer area. The isotope data set was completed with S isotope analyses of arsenide and sulfarsenide minerals from five ore deposits (Filon 7/5, Aghbar, Tamdrost, Ightem and Aït-Ahmane) and of some whole-rock regional samples. Results show that ores formed during multi-episodic hydrothermal events connected with hercynian reactivation of Devonian-Carboniferous faults, supporting previous geochronologic dating. The obtained Pb, Sr, Nd and S isotopic signatures of ore minerals and regional rocks further show that ophiolite-related lithologies became isotopically modified by interaction with crustal material and afterwards acted as the main source of ore-forming elements. Nevertheless, isotopic data do not fully concur with such a simple scenario but are quite consistent with a rather complex interpretation based on multi-source origin of some elements and isotopes scavenged from a number of isotopically different lithologies both from the inferred basement and the volcanic and sedimentary cover. © 2022 The Author(s

Impact of particles tracking model of nanofluid on forced convection heat transfer within a wavy horizontal channel

Development of modern heat exchangers or solar collectors is related to the analysis of working fluid flow and heat transfer within different channels. The energy transport enhancement can be reached by including nanofluids as working media and irregular channels to intensify the heat removal. The present research is devoted to computational analysis of nanosuspension forced convection in a horizontal wavy channel under the impact of heating from the upper wavy surface. The single-phase nanofluid approach with experimentally-based correlations for viscosity and thermal conductivity holds implemented for an investigation in combination with Newton's second law for the description of the motion of the nanoparticle within the channel. The formulated boundary-value problem has been worked out by the finite element technique. Rules of Reynolds number, number of channel waviness, and dimensionless time on nanoliquid flow, energy transport and nanoparticles motion within the channel as well as average parameters. It has occurred that a rise from Reynolds number characterizes a narrowing of the fluid tube within the channel with an improvement of the average velocity and average Nusselt number. Augmentation of the channel waviness number results in an increment of the average particles velocity and average temperature

Low Metal Loading (Au, Ag, Pt, Pd) Photo‐Catalysts Supported on TiO2 for Renewable Processes

Photo‐catalysts based on titanium dioxide, and modified with highly dispersed metallic nanoparticles of Au, Ag, Pd and Pt, either mono‐ or bi‐metallic, have been analyzed by multiple characterization techniques, including XRD, XPS, SEM, EDX, UV‐Vis and N2 adsorption/desorption. Mono‐metallic photo‐catalysts were prepared by wet impregnation, while bi‐metallic photocatalysts were obtained via deposition‐precipitation (DP). The relationship between the physico‐chemical properties and the catalyst’s behavior for various photo‐synthetic processes, such as carbon dioxide photo‐reduction to liquid products and glucose photo‐reforming to hydrogen have been investigated. Among the tested materials, the catalysts containing platinum alone (i.e., 0.1 mol% Pt/TiO2) or bi‐metallic gold‐containing materials (e.g., 1 wt% (AuxAgy)/TiO2 and 1 wt% (AuxPtz)/TiO2) showed the highest activity, presenting the best results in terms of productivity and conversion for both applications. The textural, structural and morphological properties of the different samples being very similar, the main parameters to improve performance were function of the metal as electron sink, together with optoelectronic properties. The high activity in both applications was related to the low band gap, that allows harvesting more energy from a polychromatic light source with respect to the bare TiO2. Overall, high selectivity and productivity were achieved with respect to most literature data

cardiovascular manifestations in patients infected with the human immunodeficiency virus

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A simple, cost-effective but highly efficient system for deriving ventricular cardiomyocytes from human pluripotent stem cells

published_or_final_versio

Spread, circulation, and evolution of the Middle East respiratory syndrome coronavirus

The Middle East respiratory syndrome coronavirus (MERS-CoV) was first documented in the Kingdom of Saudi Arabia (KSA) in 2012 and, to date, has been identified in 180 cases with 43% mortality. In this study, we have determined the MERS-CoV evolutionary rate, documented genetic variants of the virus and their distribution throughout the Arabian peninsula, and identified the genome positions under positive selection, important features for monitoring adaptation of MERS-CoV to human transmission and for identifying the source of infections. Respiratory samples from confirmed KSA MERS cases from May to September 2013 were subjected to whole-genome deep sequencing, and 32 complete or partial sequences (20 were ≥99% complete, 7 were 50 to 94% complete, and 5 were 27 to 50% complete) were obtained, bringing the total available MERS-CoV genomic sequences to 65. An evolutionary rate of 1.12 × 10−3 substitutions per site per year (95% credible interval [95% CI], 8.76 × 10−4; 1.37 × 10−3) was estimated, bringing the time to most recent common ancestor to March 2012 (95% CI, December 2011; June 2012). Only one MERS-CoV codon, spike 1020, located in a domain required for cell entry, is under strong positive selection. Four KSA MERS-CoV phylogenetic clades were found, with 3 clades apparently no longer contributing to current cases. The size of the population infected with MERS-CoV showed a gradual increase to June 2013, followed by a decline, possibly due to increased surveillance and infection control measures combined with a basic reproduction number (R0) for the virus that is less than 1