bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Character and Economic Significance of Precambrian Paleoweathering and Erosion Surfaces in Southern Africa
Authors: Button Andrew , Tyler Noel 
Published: May 2021

Abstract
A disproportionately large number of mineral deposits is associated with Precambrian weathering and erosion surfaces. In southern Africa such surfaces range in age from 3,200 to 600 m.y. and are developed on rocks as diverse as granites, volcanics (both basic and acid), arenites, shales, carbonates, and iron-formations. The sericitic arenites that host the auriferous-uraniferous conglomerates of the Witwatersrand and other basins of comparable age were almost certainly derived from granitic paleosols. There is some evidence to suggest that uranium was leached by paleoground water during the formation of such paleosols. We suggest that some of this uranium may have become fixed in diagenetic titania skeletons in conglomerate paleo-aquifers. In addition to chemical concentration factors, it has long been recognized that erosive truncation and reworking of older conglomerates were important ways of creating mechanical concentrations of gold and uranium along early Proterozoic and late Archean unconformities.
In several areas in southern Africa basic lavas were weathered during the early Proterozoic or earlier times to yield an alumina-rich (≥ 30% Al2O3) paleosol. Such paleosols represent a vast resource of nonbauxitic alumina.
Unconformities that cut across Precambrian carbonate rocks are marked by paleokarst surfaces, which have acted as emplacement loci for deposits as diverse as the fluorite (lead, zinc) deposits of the western Transvaal to the lead-zinc-copper deposits in the Tsumeb mine of South West Africa-Namibia. Manganese deposits are characteristically associated with erosion surfaces cut across early Proterozoic carbonate formations both in South Africa and in Western Australia. Apparently the paleoatmosphere some 2,200 to 2,300 m.y. ago contained enough oxygen to oxidize (and fix on the unconformity) both Mn and Fe that had previously been held in divalent form in carbonate minerals.
Erosion surfaces that cut across iron-formations are commonly mantled by iron-formation clast conglomerates. These conglomerates are sometimes enriched, presumably by paleoground water, to high-grade, conglomerate-textured hematite ore.
The vast period of geologic time represented by unconformities was probably the most potent factor in mineral concentration. Given time, normal geologic processes can achieve a high degree of concentration of minerals. Other important factors identified include paleotopography (due to differential erosion), solution by (and precipitation from) paleoground water, biological action, and porosity contrasts adjacent to unconformities. Continued study of Precambrian paleoweathering and erosion surfaces promises to be an exceptionally fertile field for research, both in mineral deposits science, and in advancing our understanding of the fundamental questions of terrestrial atmospheric-hydrospheric evolution.
Well Logging and Borehole Geophysics in Mineral Exploration
Authors: Glenn William E. , Hohmann Gerald W. 
Published: May 2021

Abstract
Both well logging and borehole geophysics are assuming greater importance in mineral exploration and development as targets become deeper, as drilling costs increase, and as solution mining becomes necessary. Resistivity and induced polarization are the most important logs in base metal applications because they can be used to estimate sulfide content and to aid interpretation of surface surveys. Natural gamma-ray logs are used extensively to estimate uranium content; a recently developed cryogenic logging tool measures an early daughter product of uranium in order to avoid disequilibrium problems. Other logging tools, usually used in combination, provide information on physical properties such as fracturing, density, and porosity, which are important for solution mining, and on potassium, magnetite, sulfide, and chemically bound water content. Borehole assaying with neutron activation is a promising area of current research. Borehole geophysical techniques such as mise a la masse, induced polarization, resistivity, and electromagnetics greatly increase, at little additional cost, the amount of information derived from a drill hole.
L’inclusion des perspectives autochtones dans le programme d’immersion française en Colombie-Britannique : les succès d’enseignants et d’enseignantes allochtones
Authors: Côté Isabelle 
Published: May 2021

Dans cet article, nous présentons les résultats d’une recherche exploratoire menée dans le cadre de notre recherche doctorale auprès d’enseignants et d’enseignantes allochtones du programme d’immersion française qui doivent inclure les perspectives autochtones dans leur pratique depuis le renouvellement du programme scolaire en 2016, en Colombie-Britannique. Lors d’entrevues semi-dirigées, les enseignants et les enseignantes ont discuté des défis et des succès de l’intégration des perspectives autochtones dans leur pratique. Cet article se concentre plus spécifiquement sur les succès partagés lors de la collecte de données. Quatre catégories de succès ont émergé de l’analyse, c’est-à-dire l’intégration des perspectives autochtones par le biais : 1) des compétences essentielles du curriculum renouvelé; 2) de la littérature; 3) de l’apprentissage expérientiel; 4) des rencontres avec des personnes autochtones. Dans cet article, nous présentons l’analyse des données de deux des quatre catégories, à savoir celles liées à l’apprentissage expérientiel et aux rencontres avec des personnes autochtones.
Pédagogie autochtone et pédagogie du lieu : proposition d’un modèle d’enseignement autochtonisé
Authors: Campeau Diane 
Published: May 2021

Dans le cadre d’une recherche-action un modèle pour l’intégration des dimensions culturelles autochtones dans des activités d’enseignement-apprentissage a été développé en ayant recours à une pédagogie dite « hybride », inspirée à la fois de la pédagogie autochtone et de la pédagogie du lieu. La recherche a été effectuée dans deux écoles publiques de niveau primaire, au Québec, et dont la proportion d’élèves autochtones dépasse les 50 %. Le personnel enseignant composé de 10 membres ainsi que 2 Aînées autochtones ont participé à la création de 26 activités d’enseignement-apprentissage dans une démarche collaborative. Dans le modèle proposé qui s’inscrivait dans une volonté d’autochtoniser l’enseignement, il convient de retenir le rôle des Aînées et l’importance de la langue autochtone. Il faut retenir également l’appropriation par le personnel enseignant des fondements pédagogiques autochtones au moyen d’un concept simplifié de la pédagogie hybride. Les résultats ont toutefois mis en lumière le manque de connaissance du personnel enseignant quant aux dimensions culturelles autochtones et l’absence de certaines de ces dimensions dans le curriculum québécois.
L’admiration pour celles qui en font toujours plus que ce que leur devoir commande : quel impact pour les travailleuses sociales de l’Ontario et du Québec ?
Authors: Richard Stéphane , Gervais Roger 
Published: May 2021

Toujours animé par des analyses qui privilégient l’étude des normativités en collision dans leur propension à éclairer la relation entre l’organisation du travail et la santé des professionnelles, nous avons, pour le présent texte, isolé cet énoncé : « Je trouve admirable quelqu’un qui est capable de faire plus que ce que son devoir commande ». Tiré d’un questionnaire d’enquête utilisé en 2012-2013 auprès de 1 197 travailleuses et travailleurs sociaux du Québec de l’Ontario, cet énoncé nous permettra de savoir si ce genre de comparaison dite ascendante affectera la souffrance au travail. Nos résultats seront aussi testés en présence de deux ensembles de variables de contrôle : les conditions de travail et les facteurs structuro-organisationnels. De nombreuses études confirment déjà l’influence de ces facteurs sur le bien-être et la souffrance au travail. Cherchons donc à voir si, en plus de ces variables contrôles, le fait de se comparer aux pairs au travail qui se livrent à l’hyperactivité professionnelle affecte le bien-être en dépit des autres variables imposantes.
Presence and Virulence Potential of Aeromonas hydrophila in Selected Water Sources for Household Consumption in Makurdi, Benue State
Authors: Mnguchivir Tersoo-Abiem Evelyn , Chukwuma Ariahu Charles , Agba Igyor Micheal 
Published: May 2021

This study was conducted to investigate the prevalence of Aeromonas hydrophila in selected drinking water sources in Makurdi. A total of 100 water samples (Tap, river, stream, well, pond and borehole water) were collected from different locations in Makurdi. Isolation and identification of the organism was performed using standard microbiological techniques. Further confirmation of the isolates as Aeromonas hydrophila was carried out using the Microbact 24E detection kit and polymerase chain reaction (PCR). A. hydrophila was detected in 12 (12%) out of the 100 samples; 6.67%, 8.82%, 7.14%, 25%, 30% and 20% of tap, well, borehole, river, pond and stream water samples respectively. The highest isolation rate of A. hydrophila (30%) was from pond water. All A. hydrophila isolated exhibited heamolysin, protease and lipase activity. The findings of this study revealed that treated and untreated drinking water sources in Makurdi are contaminated with potentially virulent A. hydrophila strains which may pose a health risk to consumers. Therefore, basic water treatment should be applied to drinking water to reduce public health threat posed by this finding.
Van der Waals Integration Based on Two‐Dimensional Materials for High‐Performance Infrared Photodetectors
Authors: Wang Haoyun , Li Zexin , Li Dongyan , Chen Ping , Pi Lejing , Zhou Xing , Zhai Tianyou 
Published: May 2021

AbstractInfrared photodetectors have been widely applied in various fields, including thermal imaging, biomedical imaging, and communication. Van der Waals (vdW) integration based on 2D materials provides a new solution for high‐performance infrared photodetectors due to the versatile device configurations and excellent photoelectric properties. In recent years, great progress has been made in infrared photodetectors based on vdW integration. In this review, recent progress in vdW integration‐based infrared photodetectors is presented. First, the working mechanisms and advantages of photodetectors with different structures and band alignments are presented. Then, the recent progress of vdW integration‐based infrared photodetectors is reviewed, focusing on 2D/nD (n = 0, 1, 2, 3) vdW integration, and the band engineering as well as the performance of the photodetectors are discussed in detail. Finally, a summary is delivered, and the challenges and future directions of vdW integration‐based infrared photodetectors are provided.
Versatile Solution‐Processed Organic–Inorganic Hybrid Superlattices for Ultraflexible and Transparent High‐Performance Optoelectronic Devices
Authors: Le Minh Nhut , Baeg Kang‐Jun , Kim Kyung‐Tae , Kang Seung‐Han , Choi Byung Doo , Park Chan‐Yong , Jeon Seong‐Pil , Lee Sol , Jo Jeong‐Wan , Kim Seonhyoung , Park Jun‐Gu , Ho Dongil , Hong Jongin , Kim Miso , Kim Han‐Ki , Kim Choongik , Kim Kwanpyo , Kim Yong‐Hoon , Park Sung Kyu , Kim Myung‐Gil 
Published: May 2021

AbstractCrystalline or amorphous metal oxides are widely used in various optoelectronic devices as key components, such as transparent conductive electrodes, dielectrics or semiconducting active layers for thin‐film transistor (TFT) backplanes in large‐area displays, photovoltaics, and light‐emitting diodes. Although crystalline inorganic materials demonstrate outstanding optoelectronic performance, owing to their wide bandgaps, large conductivities, and high carrier mobilities, their inherent brittleness makes them vulnerable to mechanical stress, thereby limiting the use of metal‐oxide films in emerging flexible electronic applications. In this study, stress‐diffusive organic–inorganic hybrid superlattice nanostructures are developed to overcome the mechanical limitation of crystalline oxides and to provide high mechanical stability to metal‐oxide semiconductors. In particular, hybrid transparent superlattice electrodes based on crystalline indium–tin oxide exhibit high electrical conductivities of up to 555 S cm–1 (resistance variation < 3%) and effectively reduce the mechanical stress on the inorganic layer (up to 10 000 bending cycles with a radius of 1 mm). Furthermore, to ensure the viability of the hybrid superlattice flexible electronics, all solution‐processed superlattice crystalline indium–gallium‐oxide TFTs are implemented on a thin (≈5 µm) polyimide substrate, providing highly robust and excellent electrical performance (average mobility of 7.6 cm2 V–1 s–1).
Polymorphism in Non‐Fullerene Acceptors Based on Indacenodithienothiophene
Authors: Marina Sara , Scaccabarozzi Alberto D. , Gutierrez‐Fernandez Edgar , Solano Eduardo , Khirbat Aditi , Ciammaruchi Laura , Iturrospe Amaia , Balzer Alex , Yu Liyang , Gabirondo Elena , Monnier Xavier , Sardon Haritz , Anthopoulos Thomas D. , Caironi Mario , Campoy‐Quiles Mariano , Müller Christian , Cangialosi Daniele , Stingelin Natalie , Martin Jaime 
Published: May 2021

AbstractOrganic solar cells incorporating non‐fullerene acceptors (NFAs) have reached remarkable power conversion efficiencies of over 18%. Unlike fullerene derivatives, NFAs tend to crystallize from solutions, resulting in bulk heterojunctions that include a crystalline acceptor phase. This must be considered in any morphology‐function models. Here, it is confirmed that high‐performing solution‐processed indacenodithienothiophene‐based NFAs, i.e., ITIC and its derivatives ITIC‐M, ITIC‐2F, and ITIC‐Th, exhibit at least two crystalline forms. In addition to highly ordered polymorphs that form at high temperatures, NFAs arrange into a low‐temperature metastable phase that is readily promoted via solution processing and leads to the highest device efficiencies. Intriguingly, the low‐temperature forms seem to feature a continuous network that favors charge transport despite of a poorly order along the π–π stacking direction. As the optical absorption of the structurally more disordered low‐temperature phase can surpass that of the more ordered polymorphs while displaying comparable—or even higher—charge transport properties, it is argued that such a packing structure is an important feature for reaching highest device efficiencies, thus, providing guidelines for future materials design and crystal engineering activities.
User Tracking and Wireless Digital Transmission through a Programmable Metasurface
Authors: Wan Xiang , Xiao Chao Kun , Huang He , Xiao Qiang , Xu Wei , Wang Jia Wei , Huang Zi Ai , Cheng Qiang , Jin Shi , Cui Tie Jun 
Published: May 2021

AbstractUser tracking has been an important aspect in wireless communications. Commonly, distributed apertures such as array antennas or multiple sensors are needed in wireless communication systems to achieve spatial resolutions for user tracking. Here it is proposed to realize the user tracking and wireless digital transmission simultaneously by using a single metasurface aperture. The reflection‐type metasurface consists of many subwavelength binary reconfigurable units. By programming these binary units, the metasurface can steer waves radiated from a horn antenna to a specified direction with different digital radiation phases. With this function, the metasurface can track the users by steering directional beams and transmit phase‐modulated digital signals through the directional beams. A prototype based on a programmable metasurface is developed and experiments in terms of cyclic redundancy check (CRC) and constellation diagrams are performed. The measured results prove that the user tracking and wireless digital transmission can be integrated through the programmable metasurface. Considering the simple architecture and flexible controlling features, the proposed methodology has great application prospect in integrated radar‐communication systems and cognitive electronic systems.
Phase Nonreciprocity of Microwave‐Frequency Surface Acoustic Waves in Hybrid Heterostructures with Magnetoelastic Coupling
Authors: Verba Roman , Bankowski Elena N. , Meitzler Thomas J. , Tiberkevich Vasil , Slavin Andrei 
Published: May 2021

AbstractMagnetoelastic coupling is considered as one of the most reliable method to induce nonreciprocity of propagation losses of microwave‐frequency surface acoustic waves (SAW) and other acoustic modes propagating in nonmagnetic‐ferromagnetic heterostructures. Here, it is demonstrated theoretically that magnetoelastic coupling can also induce phase nonreciprocity of SAW, which is necessary for the development of SAW circulators and other nonreciprocal solid‐state‐acoustic devices. In contrast to previous studies, induction of the phase nonreciprocity requires the coupling of SAW to a strongly nonreciprocal spin wave (SW), having the nonreciprocal splitting of the SW spectrum much larger than the strength of the magnetoelastic coupling, which, in turn, should be much larger than the geometric mean of the SW and SAW damping rates. In this case, the hybridized SAW in the spectral region between the magnetoelastic gaps demonstrate significant phase nonreciprocity, retaining, at the same time, propagation losses that are close to those of unhybridized SAW. Possible practical realization of nonreciprocal SAW phase shifters and SAW‐ring‐based circulators based on hybridized waves in acoustic crystal and synthetic antiferromagnetic heterostructures is discussed.
The observation of art and the art of observing individuals with physical differences
Authors: Mangione Salvatore 
Published: May 2021

AbstractAstute observation is a fundamental skill in medical care because not only it is crucial for the detection of patients' emotions (which is a prerequisite for empathy) but also it can often yield diagnoses at first sight. The Germans call this technique “augenblickdiagnose,” and indeed, gestalt diagnosis together with systematic review is used by dysmorphologists to identify syndromes. Artists have traditionally excelled at skilled observation since it is necessary for realistic portrayal of the human form. Thus, not surprisingly, they have also often depicted syndromes and defects in artworks, decades or even centuries earlier than their medical counterparts' description. Although physicians should avoid overdiagnosing or medicalizing what may be ethnic variations, personality traits, or just artistic style, this commentary will review how syndromes and various physical differences have been represented in artworks. It will then provide practical tips on how to become better observers. The historical relationship between artists and physicians provides context for our mutual diagnostic and interpretative pursuits.
Skeletal dysplasias in art and antiquities: A cultural journey through genes, environment, and chance
Authors: Botto Lorenzo D. 
Published: May 2021

AbstractPeople with skeletal dysplasias have left traces in art and antiquities through ages and cultures worldwide, in Ancient Egypt, Classical Greece, Sub‐Saharan Africa, Asia, and Europe. Such traces record the impact of people with skeletal dysplasia on society and culture—in daily life, religion, and mythology. However, identifying (“diagnosing”) skeletal dysplasia in artifacts and interpreting what such depictions meant within the culture in which they were created is extremely challenging and at times impossible. The objectives of this short and necessarily selective survey are to present a few examples of art through different ages and cultures as a springboard for discussion not only on potential medical diagnoses but also on the lives of people with chondrodysplasia and how they were valued in the society in which they lived. The artifacts were selected from Ancient Egypt, Classical Greece, Mesoamerica (Maya), Sub‐Saharan Africa (Kingdom of Benin), Tang China, and 17th Century Europe. In some cases, surviving artifacts with likely depictions of skeletal dysplasia are few and their cultural context incompletely understood. Nevertheless, certain themes and attitudes seem to repeat across different times and regions, though some cultures, such as those in Ancient Egypt, appeared to have had a comparatively positive view of people with restricted growth and chondrodysplasia.
Reflections on observing faces in art
Authors: Battaglia Agatino , Carey John C. 
Published: May 2021

AbstractThe experience of art provides the visitor of a museum or gallery with the opportunity to contemplate and share the human condition both from the physical and psychological point of view. Because of the accessibility and the number of museums throughout Europe, classical European art as both sculpture and painting, affords the viewer the opportunity to experience life from one part of the world over centuries of history. These museums occasionally exhibit pieces showing a person with a human disorder and physical differences. On viewing such artwork, practitioners of health care, especially dysmorphologists, usually find themselves observing such pieces within the context of their practice. In this essay, the coauthors reflect on paintings and sculptures which remind us of our patients with similar physical and medical conditions. Various works of art also provide the opportunity to observe and view the human face from many vantage points and times in history. Several paintings are cited to illustrate the central themes of the Commentary: the human circumstance of disease and differences and the skill of observing and describing the human face.
Mechanistic Study of Carbon Dioxide Hydrogenation over Pd/ZnO‐Based Catalysts: The Role of Palladium–Zinc Alloy in Selective Methanol Synthesis
Authors: Zabilskiy Maxim , Sushkevich Vitaly L. , Newton Mark A. , Krumeich Frank , Nachtegaal Maarten , van Bokhoven Jeroen A. 
Published: May 2021

AbstractPd/ZnO catalysts show good activity and high selectivity to methanol during catalytic CO2 hydrogenation. The Pd‐Zn alloy phase has usually been considered as the active phase, though mechanistic studies under operando conditions have not been conducted to verify this. Here, we report a mechanistic study under realistic conditions of methanol synthesis, using in situ and operando X‐ray absorption spectroscopy, X‐ray powder diffraction, and time‐resolved isotope labeling experiments coupled with FTIR spectroscopy and mass spectrometry. Pd‐Zn alloy‐based catalysts, prepared through reduction of a heterobimetallic PdIIZnII acetate bridge complex, and which do not contain zinc oxide or any PdZn/ZnO interface, produce mostly CO. The Pd‐Zn phase is associated with the formation of CO, and does not provide the active sites required to produce methanol from the direct hydrogenation of carbon dioxide. The presence of a ZnO phase, in contact with a Pd‐Zn phase, is essential for efficient methanol production.