van der Waals heterostructures (vdWH) are ideal systems for exploring light–matter interactions at the atomic scale. In particular, structures with a type-II band alignment can yield detailed insight ...into carrier-photon conversion processes, which are central to, for example, solar cells and light-emitting diodes. An important first step in describing such processes is to obtain the energies of the interlayer exciton states existing at the interface. Here we present a general first-principles method to compute the electronic quasi-particle (QP) band structure and excitonic binding energies of incommensurate vdWHs. The method combines our quantum electrostatic heterostructure (QEH) model for obtaining the dielectric function with the many-body GW approximation and a generalized 2D Mott–Wannier exciton model. We calculate the level alignment together with intra- and interlayer exciton binding energies of bilayer MoS2/WSe2 with and without intercalated hBN layers, finding excellent agreement with experimental photoluminescence spectra. A comparison to density functional theory calculations demonstrates the crucial role of self-energy and electron–hole interaction effects.
Big data and artificial intelligence has revolutionized science in almost every field – from economics to physics. In the area of materials science and computational heterogeneous catalysis, this ...revolution has led to the development of scientific data repositories, as well as data mining and machine learning tools to investigate the vast materials space. The goal of using these tools is to establish a deeper understanding of the relations between materials properties and activity, selectivity and stability – the important figures of merit in catalysis. Based on these insights, catalyst design principles can be established, which hopefully lead us to discover highly efficient catalysts to solve pressing issues for a sustainable future and the synthesis of highly functional materials, chemicals and pharmaceuticals. The inherent complexity of catalytic reactions quests for machine learning methods to efficiently navigate through the high‐dimensional hyper‐surfaces in structure optimization problems to determine relevant chemical structures and transition states. In this review, we show how cutting edge data infrastructures and machine learning methods are being used to address problems in computational heterogeneous catalysis.
Advances in machine learning and data science hold great potential for the rapid computational screening of solid‐state catalyst materials candidates and to accelerate the computation of potential energy landscapes. In this review, we outline important data science and machine learning concepts and show how these are applied in the field of computational heterogeneous catalysis. We cover topics like data storage and sharing, materials featurization and using machine learning models for predictive and mechanistic studies.
After the completion of the gallium solar neutrino experiments at the Laboratori Nazionali del Gran Sasso (Gallex: 1991–1997; GNO: 1998–2003) we have retrospectively updated the Gallex results with ...the help of new technical data that were impossible to acquire for principle reasons before the completion of the low rate measurement phase (that is, before the end of the GNO solar runs). Subsequent high rate experiments have allowed the calibration of absolute internal counter efficiencies and of an advanced pulse shape analysis for counter background discrimination. The updated overall result for Gallex (only) is 73.4−7.3+7.1 SNU. This is 5.3% below the old value of 77.5−7.8+7.5 SNU (Gallex Collaboration, W. Hampel et al., 1999 1), with a substantially reduced error. A similar reduction is obtained from the reanalysis of the 51Cr neutrino source experiments of 1994/1995.
Purpose: Despite the strong belief in sports programs as a setting in which socially vulnerable youth can develop life skills, no overview exists of life skill development in sports programs serving ...this youth group. Therefore, the present systematic review provides an overview of the evidence on life skill development in sports programs serving socially vulnerable youth and, insofar as it was investigated in the included studies, of the conditions conducive to life skill development in these sports programs. Method: Potentially relevant studies published during 1990 to 2014 were identified by a search in 7 electronic databases. The search combined terms relating to (a) sport, (b) youth AND socially vulnerable, and (c) life skills. Eighteen of the 2,076 unique studies met the inclusion criteria. Results: Each included study reported that at least 1 life skill improved in youth who participated in the studied sports program. Improvements in cognitive and social life skills were more frequently reported than were improvements in emotional life skills. Only a few of the included studies investigated the conditions in the studied sports programs that made these programs conducive to life skill development. Conclusions: Sports programs have the potential to make a difference in the life skill development of socially vulnerable youth. This conclusion needs to be treated with some caution, because the studies experienced many challenges in reducing the risk for bias. Several alternative research strategies are suggested for future studies in this field.
Amid growing debates about globalization of higher education (HE) reproducing inequalities, an analysis of race as the organizing influence underlying this global phenomenon remains absent. This ...conceptual essay argues that our understanding of globalization of HE would benefit from an intersectional understanding of critical Whiteness studies and temporal studies to help racialize and further temporalize this phenomenon. It introduces
Whiteness as futurity
framework and its three components: Whiteness as (a) aspiration, (b) investment, and (c) malleability. Drawing on this framework, it provides a critical race temporal account of globalization of HE by critically examining two contemporary global HE trends, namely: (a) the global diffusion of liberal education, and (b) the growing use of global university rankings (GURs). It argues that
Whiteness as futurity
colonizes (or orients) global subjects’ (nation-states’, policy makers’, institutions’, and individuals’) imaginaries and reinforces the asymmetrical movements, networks, and untethered economies underpinning global HE. The article concludes that educators should consider seriously the insights of Whiteness studies in reconceptualizing globalization of HE.
Drawing on the global interdisciplinary literature on decolonizing curriculum and pedagogy (DCP) in higher education, we critically examined the idea of decolonizing in the context of disciplines and ...universities around the world. Based on a critical analysis of 207 articles and book chapters published in English and centering a geopolitics of knowledge frame, we present three themes: (a) decolonizing meaning(s), (b) actualizing decolonization, and (c) challenges to actualizing, all related to DCP. We observed three major meanings of decolonization and four ways to actualize DCP that were associated with geographical, disciplinary, institutional, and/or stakeholder contexts. We argue that while there are similarities within the literature, ultimately the meanings, actualizations, and challenges of DCP are contextual, which has political and epistemological consequences. We end by offering directions for education research on DCP, revealing the possibility for a field or discipline of decolonial studies.
We present a new open repository for chemical reactions on catalytic surfaces, available at https://www.catalysis-hub.org . The featured database for surface reactions contains more than 100,000 ...chemisorption and reaction energies obtained from electronic structure calculations, and is continuously being updated with new datasets. In addition to providing quantum-mechanical results for a broad range of reactions and surfaces from different publications, the database features a systematic, large-scale study of chemical adsorption and hydrogenation on bimetallic alloy surfaces. The database contains reaction specific information, such as the surface composition and reaction energy for each reaction, as well as the surface geometries and calculational parameters, essential for data reproducibility. By providing direct access via the web-interface as well as a Python API, we seek to accelerate the discovery of catalytic materials for sustainable energy applications by enabling researchers to efficiently use the data as a basis for new calculations and model generation.
There is a paucity of global data on cardiovascular disease (CVD) prevalence in people with type 2 diabetes (T2D). The primary objective of the CAPTURE study was to estimate the prevalence of ...established CVD and its management in adults with T2D across 13 countries from five continents. Additional objectives were to further characterize the study sample regarding demographics, clinical parameters and medication usage, with particular reference to blood glucose-lowering agents (GLAs: glucagon-like peptide-1 receptor agonists and sodium-glucose co-transporter-2 inhibitors) with demonstrated cardiovascular benefit in randomized intervention trials.
Data were collected from adults with T2D managed in primary or specialist care in Australia, China, Japan, Czech Republic, France, Hungary, Italy, Argentina, Brazil, Mexico, Israel, Kingdom of Saudi Arabia, and Turkey in 2019, using standardized methodology. CVD prevalence, weighted by diabetes prevalence in each country, was estimated for the overall CAPTURE sample and participating countries. Country-specific odds ratios for CVD prevalence were further adjusted for relevant demographic and clinical parameters.
The overall CAPTURE sample included 9823 adults with T2D (n = 4502 from primary care; n = 5321 from specialist care). The overall CAPTURE sample had median (interquartile range) diabetes duration 10.7 years (5.6-17.9 years) and glycated hemoglobin 7.3% (6.6-8.4%) 56 mmol/mol (49-68 mmol/mol). Overall weighted CVD and atherosclerotic CVD prevalence estimates were 34.8% (95% confidence interval CI 32.7-36.8) and 31.8% (95% CI 29.7-33.8%), respectively. Age, gender, and clinical parameters accounted for some of the between-country variation in CVD prevalence. GLAs with demonstrated cardiovascular benefit were used by 21.9% of participants, which was similar in participants with and without CVD: 21.5% and 22.2%, respectively.
In 2019, approximately one in three adults with T2D in CAPTURE had diagnosed CVD. The low use of GLAs with demonstrated cardiovascular benefit even in participants with established CVD suggested that most were not managed according to contemporary diabetes and cardiology guidelines. Study registration NCT03786406 (registered on December 20, 2018), NCT03811288 (registered on January 18, 2019).
A comprehensive database of chemical properties on a vast set of transition metal surfaces has the potential to accelerate the discovery of novel catalytic materials for energy and industrial ...applications. In this data descriptor, we present such an extensive study of chemisorption properties of important adsorbates - e.g., C, O, N, H, S, CH
, OH, NH, and SH - on 2,035 bimetallic alloy surfaces in 5 different stoichiometric ratios, i.e., 0%, 25%, 50%, 75%, and 100%. To our knowledge, it is the first systematic study to compile the adsorption properties of such a well-defined, large chemical space of catalytic interest. We propose that a collection of catalytic properties of this magnitude can assist with the development of machine learning enabled surrogate models in theoretical catalysis research to design robust catalysts with high activity for challenging chemical transformations. This database is made publicly available through the platform www.Catalysis-hub.org for easy retrieval of the data for further scientific analysis.
The discovery of high-performing and stable materials for sustainable energy applications is a pressing goal in catalysis and materials science. Understanding the relationship between a material’s ...structure and functionality is an important step in the process, such that viable polymorphs for a given chemical composition need to be identified. Machine-learning-based surrogate models have the potential to accelerate the search for polymorphs that target specific applications. Herein, we report a readily generalizable active-learning (AL) accelerated algorithm for identification of electrochemically stable iridium oxide polymorphs of IrO2 and IrO3. The search is coupled to a subsequent analysis of the electrochemical stability of the discovered structures for the acidic oxygen evolution reaction (OER). Structural candidates are generated by identifying all 956 structurally unique AB2 and AB3 prototypes in existing materials databases (more than 38000). Next, using an active learning approach, we find 196 IrO2 polymorphs within the thermodynamic amorphous synthesizability limit and reaffirm the global stability of the rutile structure. We find 75 synthesizable IrO3 polymorphs and report a previously unknown FeF3-type structure as the most stable, termed α-IrO3. To test the algorithms performance, we compare to a random search of the candidate space and report at least a 2-fold increase in the rate of discovery. Additionally, the AL approach can acquire the most stable polymorphs of IrO2 and IrO3 with fewer than 30 density functional theory optimizations. Analysis of the structural properties of the discovered polymorphs reveals that octahedral local coordination environments are preferred for nearly all low-energy structures. Subsequent Pourbaix Ir–H2O analysis shows that α-IrO3 is the globally stable solid phase under acidic OER conditions and supersedes the stability of rutile IrO2. Calculation of theoretical OER surface activities reveal ideal weaker binding of the OER intermediates on α-IrO3 than on any other considered iridium oxide. We emphasize that the proposed AL algorithm can be easily generalized to search for any binary metal oxide structure with a defined stoichiometry.
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