Machine Learning Models Capture Plasmon Dynamics in Ag Nanoparticles

Highly energetic electron-hole pairs (hot carriers) formed from plasmon decay in metallic nanostructures promise sustainable pathways for energy-harvesting devices. However, efficient collection before thermalization remains an obstacle for realization of their full energy generating potential. Addressing this challenge requires detailed understanding of physical processes from plasmon excitation in metal to their collection in a molecule or a semiconductor, where atomistic theoretical investigation may be particularly beneficial. Unfortunately, first-principles theoretical modeling of these processes is extremely costly, limiting the analysis to systems with a few 100s of atoms. Recent advances in machine learned interatomic potentials suggest that dynamics can be accelerated with surrogate models which replace the full solution of the Schroedinger Equation. Here, we modify an existing neural network, Hierarchically Interacting Particle Neural Network (HIP-NN), to predict plasmon dynamics in Ag nanoparticles. We demonstrate the model's capability to accurately predict plasmon dynamics in large nanoparticles of up to 561 atoms not present in the training dataset. More importantly, with machine learning models we gain a speed-up of about 200 times as compared with the rt-TDDFT calculations when predicting important physical quantities such as dynamic dipole moments in Ag55 and about 4000 times for extended nanoparticles that are 10 times larger. This underscores the promise of future machine learning accelerated electron/nuclear dynamics simulations for understanding fundamental properties of plasmon-driven hot carrier devices

Hot Hole versus Hot Electron Transport at Copper/GaN Heterojunction Interfaces

Among all plasmonic metals, copper (Cu) has the greatest potential for realizing optoelectronic and photochemical hot-carrier devices, thanks to its CMOS compatibility and outstanding catalytic properties. Yet, relative to gold (Au) or silver (Ag), Cu has rarely been studied and the fundamental properties of its photoexcited hot carriers are not well understood. Here, we demonstrate that Cu nanoantennas on p-type gallium nitride (p-GaN) enable hot-hole-driven photodetection across the visible spectrum. Importantly, we combine experimental measurements of the internal quantum efficiency (IQE) with ab initio theoretical modeling to clarify the competing roles of hot-carrier energy and mean-free path on the performance of hot-hole devices above and below the interband threshold of the metal. We also examine Cu-based plasmonic photodetectors on corresponding n-type GaN substrates that operate via the collection of hot electrons. By comparing hot hole and hot electron photodetectors that employ the same metal/semiconductor interface (Cu/GaN), we further elucidate the relative advantages and limitations of these complementary plasmonic systems. In particular, we find that harnessing hot holes with p-type semiconductors is a promising strategy for plasmon-driven photodetection across the visible and ultraviolet regimes. Given the technological relevance of Cu and the fundamental insights provided by our combined experimental and theoretical approach, we anticipate that our studies will have a broad impact on the design of hot-carrier optoelectronic devices and plasmon-driven photocatalytic systems

Spin-phonon relaxation from a universal \emph{ab initio} density-matrix approach

Designing new quantum materials with long-lived electron spin states urgently requires a general theoretical formalism and computational technique to reliably predict intrinsic spin relaxation times. We present a new, accurate and universal first-principles methodology based on Lindbladian dynamics of density matrices to calculate spin-phonon relaxation time ($\tau_s$) of solids with arbitrary spin mixing and crystal symmetry. This method describes contributions of Elliott-Yafet (EY) and D'yakonov-Perel' (DP) mechanisms to spin relaxation for systems with and without inversion symmetry on an equal footing. We show that intrinsic spin and momentum relaxation times both decrease with increasing temperature; however, for the DP mechanism, spin relaxation time varies inversely with extrinsic scattering time. We predict large anisotropy of spin lifetime in transition metal dichalcogenides. The excellent agreement with experiments for a broad range of materials underscores the predictive capability of our method for properties critical to quantum information science.Comment: 12 pages, 7 figure

Hot Hole versus Hot Electron Transport at Copper/GaN Heterojunction Interfaces

Among all plasmonic metals, copper (Cu) has the greatest potential for realizing optoelectronic and photochemical hot-carrier devices, thanks to its CMOS compatibility and outstanding catalytic properties. Yet, relative to gold (Au) or silver (Ag), Cu has rarely been studied and the fundamental properties of its photoexcited hot carriers are not well understood. Here, we demonstrate that Cu nanoantennas on p-type gallium nitride (p-GaN) enable hot-hole-driven photodetection across the visible spectrum. Importantly, we combine experimental measurements of the internal quantum efficiency (IQE) with ab initio theoretical modeling to clarify the competing roles of hot-carrier energy and mean-free path on the performance of hot-hole devices above and below the interband threshold of the metal. We also examine Cu-based plasmonic photodetectors on corresponding n-type GaN substrates that operate via the collection of hot electrons. By comparing hot hole and hot electron photodetectors that employ the same metal/semiconductor interface (Cu/GaN), we further elucidate the relative advantages and limitations of these complementary plasmonic systems. In particular, we find that harnessing hot holes with p-type semiconductors is a promising strategy for plasmon-driven photodetection across the visible and ultraviolet regimes. Given the technological relevance of Cu and the fundamental insights provided by our combined experimental and theoretical approach, we anticipate that our studies will have a broad impact on the design of hot-carrier optoelectronic devices and plasmon-driven photocatalytic systems

Suspension of new generation anticoagulants in patients undergoing oral surgery. Systematic review

Antecedentes: La nueva generación de anticoagulantes, llamados también anticoagulantes orales directos (DOACs), tienen características que los vuelven más predecibles por su acción farmacocinética y farmacodinamia, rango terapéutico y dosis fijas sin necesidad de monitorización periódica. En la actualidad se conocen 2 tipos: inhibidores directos del FX activado (FXa) e inhibidores de la trombina (FIIa). Objetivo: Evaluar la indicación de suspensión de los anticoagulantes orales directos en pacientes sometidos a procedimientos de cirugía oral basado en la evidencia científica. Materiales y métodos: En esta revisión sistemática de la literatura se efectuaron búsquedas en las bases de datos de PubMed, Embase-Elsevier, EBSCO, Scopus, Science direct, Cochrane, Scielo, Ovid y ProQuest de artículos publicados entre el 1 de enero de 2010 al 31 de marzo de 2021. Se obtuvieron y analizaron 17 artículos que cumplían con los criterios de inclusión y exclusión. Resultados: En los 17 artículos, fueron evaluados un total de 840 pacientes anticoagulados con rivaroxaban, apixaban, dabigatrán y edoxaban, en los cuales se realizaron procedimientos de cirugía oral, sobre todo exodoncias e implantes dentales; dentro de estos a 782 pacientes no se les retiró el DOAC previo al procedimiento de cirugía oral y a 58 pacientes se les omitió al menos una dosis del anticoagulante. Se presentó hemorragias, principalmente leves en 17,51% de los pacientes a los que no se les retiro el DOAC. Se encontró un mayor porcentaje de hemorragias asociadas a rivaroxaban que con los demás DOACs. Conclusiones: Se recomienda no suspender los DOACs en procedimientos de cirugía oral menor, ya que la hemorragia que pudiera presentarse es generalmente leve y puede ser adecuadamente manejada con medidas hemostáticas locales.Pacientes anticoagulados sometidos a cirugía bucalBackground: The new generation of anticoagulants, also called direct oral anticoagulants (DOACs), have characteristics that make them more predictable due to their pharmacokinetic and pharmacodynamic action, therapeutic range and fixed doses without the need for periodic monitoring. Currently, 2 types are known: direct inhibitors of activated FX (FXa) and thrombin inhibitors (FIIa). Objective: To evaluate the indication for suspension of direct oral anticoagulants in patients undergoing oral surgery procedures based on scientific evidence. Materials and methods: In this systematic review of the literature, PubMed, Embase-Elsevier, EBSCO, Scopus, Science direct, Cochrane, Scielo, Ovid and ProQuest databases were searched for articles published between January 1, 2010 as of March 31, 2021. 17 articles that met the inclusion and exclusion criteria were obtained and analyzed. Results: In the 17 articles, a total of 840 anticoagulated patients with rivaroxaban, apixaban, dabigatran and edoxaban were evaluated, in whom oral surgery procedures were performed, especially extractions and dental implants; Among these, 782 patients did not have their DOAC withdrawn prior to the oral surgery procedure and 58 patients had at least one dose of anticoagulant omitted. Bleeding, mainly mild, occurred in 17.51% of the patients who did not withdraw the DOAC. A higher percentage of bleeding associated with rivaroxaban was found than with the other DOACs. Conclusions: It is recommended not to suspend DOACs in minor oral surgery procedures, since the bleeding that may occur is generally mild and can be adequately managed with local hemostatic measures.Especialista en Patología y Cirugía BucalEspecializació

Fuzzy GIS-based MCDM solution for the optimal offshore wind site selection: The Gulf of Maine case

This paper describes a multi-criterion decision-making approach for optimal off-shore wind location assessment by including fuzzy geographical information systems to prioritize the different locations and alternatives. The multi-objective framework involves a variety of elements, such as climatic, geographic, social, environmental, location, and economic factors. The proposed decision-making solution is based on a multicriteria evaluation method divided into two steps: an analytic hierarchy process and a prioritization of the alternatives in comparison to a parallel approach based on a fuzzy geographical information system solution. The Gulf of Maine (USA) is considered as a case example, owing to the relevant offshore wind potential of such an area. A descriptive statistical evaluation of the wind resource was previously carried out to characterize this area with wind speed field measurements for 10 years (2010–2019). A design proposal for a 1 GW offshore wind power plant is used in a case study based on a 15 MW variable speed wind turbine prototype recently proposed by the IEA Wind Task 37. The results include prioritization of optimal offshore wind power plant sites, levelized cost of electricity estimation, and avoided emissions in comparison to traditional supply side scenarios, mainly based on fossil fuel generation units.2021-2

Beyond the conflict: religion in the public sphere and deliberative democracy

Traditionally, liberals have confined religion to the sphere of the ‘private’ or ‘non-political’. However, recent debates over the use of religious symbols in public spaces, state financing of faith schools, and tax relief for religious organisations suggest that this distinction is not particularly useful in easing the tension between liberal ideas of equality among citizens and freedom of religion. This article deals with one aspect of this debate, which concerns whether members of religious communities should receive exemptions from regulations that place a distinctively heavy burden on them. For supporters of exemptions, protection for diverse practices and religious beliefs justifies such a special treatment. For others, this is a form of positive discrimination incompatible with equal citizenship. Drawing on Habermas’ understanding of churches as ‘communities of interpretation’ this article explores possible alternative solutions to both the ‘rule-andexemption’ approach and the ‘neutralist’ approach. Our proposal rests on the idea of mutual learning between secular and religious perspectives. On this interpretation, what is required is, firstly, generation and maintenance of public spaces in which there could be discussion and dialogue about particular cases, and, secondly, evaluation of whether the basic conditions of moral discourse are present in these spaces. Thus deliberation becomes a touchstone for the building of a shared democratic etho