bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent advances in total syntheses of natural products containing the benzocycloheptane motif
Authors: Fan Jian-Hong , Hu Ya-Jian , Li Li-Xuan , Wang Jing-Jing , Li Shao-Ping , Zhao Jing , Li Chuang-Chuang
Published: March 2021

In this review, recent progresses in the total syntheses of natural products containing the benzocycloheptane motif are presented, and key transformations for the construction of benzocycloheptane are highlighted.
Quantifying the effects of medium voltage–low voltage distribution network constraints and distributed energy resource reactive power capabilities on aggregators
Authors: Gutierrez‐Lagos Luis , Petrou Kyriacos , Ochoa Luis Fernando
Published: March 2021

Distributed energy resources (DER), such as, photovoltaic systems and batteries, are becoming common among households. Although the main objective is reducing electricity imports (bills), they could also provide system‐level services via an aggregator. However, the more DER provide services, the more important is ensuring that the corresponding operation does not result in network issues. To help DER aggregators understand the implications of network constraints, an AC optimal power flow‐based methodology is proposed to quantify the effects that three‐phase low voltage (LV) and medium voltage (MV) network constraints can have on the volume of services that can be provided for a given horizon, and the potential benefits from using DER reactive power capabilities. Using a convex multi‐period formulation that avoids binary variables for batteries and incorporates voltage‐dependent load models, the methodology maximizes DER exports (services) for service‐related periods and household self‐consumption for other periods (reducing bills). Different service periods are assessed to explore the extent of services throughout the day. Results using a realistic UK MV‐LV network with 2400+ households, show that aggregator services can be highly overestimated when neglecting MV‐LV network constraints, are influenced by voltage‐demand load characteristics, and that exploiting DER reactive power capabilities can significantly unlock further services.
Investigation of photocatalytic activity of Ag‐rutile heterojunctions
Authors: Zhu Xiaodong , Liu Hui , Wang Juan , Dai Hualong , Bai Yu , Feng Wei , Han Shihu
Published: March 2021

The pure rutile and Ag‐rutile nanomaterials were synthesised using sol–gel route and the effect of Ag concentration on the composite photocatalyst activity was investigated. The results show that the Ag0 particles are deposited on the rutile surface, forming Ag‐rutile heterojunctions. The high concentration of Ag is beneficial to inhibit the recombination of electrons and holes, meanwhile, excessive Ag particles will hinder the absorption of light source and adsorption of RhB molecules. Therefore, 2% of Ag rutile exhibits the highest photocatalytic activity.
L’agriculture burkinabè face à la crise de la Covid-19 : cas des régions du Yatenga et des Hauts-Bassins
Authors: Dugué Patrick , Kohio Edmond N. , Tiemtoré Justin
Published: March 2021

Au début de la crise sanitaire due à la Covid-19, certains observateurs ont alerté les décideurs d’une possible crise alimentaire dans les mois à venir en Afrique de l’Ouest. En vue d’alimenter ce débat, nous avons mené une étude en nous entretenant avec 75 acteurs du secteur agricole dans deux régions du Burkina Faso − le Yatenga et les Hauts-Bassins. Dans les deux situations, les agriculteurs et les éleveurs ont pu continuer leurs activités mais certains ont eu des difficultés de commercialisation. Les maraîchers et les arboriculteurs ont été les plus touchés par cette crise du fait des difficultés à écouler leurs produits périssables sur les marchés ouest-africains. Les éleveurs ont été moins concernés par la baisse des prix mais les commerçants de bétail sur pied ont aussi rencontré des difficultés à exporter vers les pays côtiers. Enfin, les sociétés cotonnières ont dû faire face à une baisse du prix international du coton-fibre et les producteurs de coton ont dû faire face à une baisse du prix d’achat du coton-graine à la fin de 2020. Malgré cette crise, l’agriculture burkinabè a continué à jouer pleinement son rôle nourricier grâce à la mobilisation des agriculteurs, des commerçants et des transporteurs, même si elle montre des fragilités dues à sa forte dépendance aux marchés extérieurs pour entre autres les légumes, le bétail, le coton, les mangues, l’anacarde et les intrants agricoles et d’élevage. Cette crise permet de réfléchir à des axes d’intervention afin de rendre l’agriculture burkinabè moins dépendante des marchés extérieurs et des facteurs de production importés. Cela implique la substitution des produits alimentaires importés par des produits locaux et une transition agroécologique permettant de réduire l’importation d’intrants de synthèse.
A study on the tensile force and shear strain of trilayer graphene
Authors: Das Dhiman Kumar , Sahoo Sushant Kumar , Purohit Pranati , Sahoo Sukadev
Published: March 2021

The study of mechanical properties of graphene is one of the hottest topics in graphene physics. As the number of graphene layers increases, the mechanical property changes. Y. Liu et al., J. Mech. Phys. Solids, 60, 591 (2012) [1] have studied the tensile force and shear strain of bilayer graphene. They observed both the parameters increase as the length increases. In this paper, we study the same parameters for trilayer graphene. In trilayer graphene, we observe that with increasing length of the material, the tensile force increases and shear strain decreases. The change of mechanical behaviour from bilayer to trilayer graphene is a transition which would continue to higher number of layers with potential implications in near future.
Design and implementation of anulus-shaped ciliary structure for four-unit MEMS vector hydrophone
Authors: Zhang Xiaoyong , Shen Nixin , Xu Qingda , Pei Yu , Lian Yuqi , Wang Weidong , Zhang Guojun , Zhang Wendong
Published: March 2021

Inspired from fish bionics, an anulus-shaped ciliary structure for four-unit MEMS vector hydrophone (AFUVH) is proposed in this paper. It replaces the previous bionic cilium-shaped structure and becomes a novel sensing structure in the four-unit MEMS vector hydrophone (FUVH), which realizes the complete simulation of the fish lateral line neuromasts structurally and functionally. It not only improves the sensitivity of FUVH, but also retains a sufficient bandwidth, which improves the overall performance of FUVH for monitoring remote ships noise. Meanwhile, this paper theoretically analyzes the performance of AFUVH for detecting acoustic signals. ANSYS 17.0 simulation is used to derive the parameters of effective structure and optimum dimension structure of annulus-shaped ciliary structure. Finally, the experimental results show that comparing with cilium-structured FUVH, the sensitivity of AFUVH with effective structure is increased by 3.92 dB, and the sensitivity of AFUVH with optimum dimension structure is increased by 5.87 dB, reaching up to −177.53 dB.
Questions and Controversies in the Clinical Application of Tyrosine Kinase Inhibitors to Treat Patients with Radioiodine-Refractory Differentiated Thyroid Carcinoma: Expert Perspectives
Authors: Verburg Frederik A. , Amthauer Holger , Binse Ina , Brink Ingo , Buck Andreas , Darr Andreas , Dierks Christine , Koch Christine , König Ute , Kreissl Michael C. , Luster Markus , Reuter Christoph , Scheidhauer Klemens , Willenberg Holger Sven , Zielke Andreas , Schott Matthias
Published: March 2021

Notwithstanding regulatory approval of lenvatinib and sorafenib to treat
radioiodine-refractory differentiated thyroid carcinoma (RAI-R DTC),
important questions and controversies persist regarding this use of these
tyrosine kinase inhibitors (TKIs). RAI-R DTC experts from German tertiary
referral centers convened to identify and explore such issues; this paper
summarizes their discussions. One challenge is determining when to start TKI
therapy. Decision-making should be shared between patients and
multidisciplinary caregivers, and should consider tumor size/burden,
growth rate, and site(s), the key drivers of RAI-R DTC morbidity and
mortality, along with current and projected tumor-related symptomatology,
co-morbidities, and performance status. Another question involves choice of
first-line TKIs. Currently, lenvatinib is generally preferred, due to
greater increase in progression-free survival versus placebo treatment and
higher response rate in its pivotal trial versus that of sorafenib;
additionally, in those studies, lenvatinib but not sorafenib showed overall
survival benefit in subgroup analysis. Whether recommended maximum or lower
TKI starting doses better balance anti-tumor effects versus tolerability is
also unresolved. Exploratory analyses of lenvatinib pivotal study data
suggest dose-response effects, possibly favoring higher dosing; however,
results are awaited of a prospective comparison of lenvatinib starting
regimens. Some controversy surrounds determination of net therapeutic
benefit, the key criterion for continuing TKI therapy: if tolerability is
acceptable, overall disease control may justify further treatment despite
limited but manageable progression. Future research should assess potential
guideposts for starting TKIs; fine-tune dosing strategies and further
characterize antitumor efficacy; and evaluate interventions to prevent
and/or treat TKI toxicity, particularly palmar-plantar
erythrodysesthesia and fatigue.
Effective impedance over ordered fields
Authors: Muranova Anna
Published: March 2021

In this paper, we study the properties of effective impedances of finite electrical networks, considering them as weighted graphs over an ordered field. We prove that a star-mesh transform of finite network does not change its effective impedance. Moreover, we consider two particular examples of infinite ladder networks (Feynman’s network or LC-network and CL-network, both with zero at infinity) as networks over the ordered Levi–Cività field R. We show that the sequence of effective impedances of finite LC-networks converges to the limit in the order topology of R, but the sequence of effective impedances of finite CL-networks does not converge in the same topology. We calculate an effective impedance of a finite ladder network as an auxiliary result.
Detecting coexisting oscillatory patterns in delay coupled Lur’e systems
Authors: Rogov Kirill , Pogromsky Alexander , Steur Erik , Michiels Wim , Nijmeijer Henk
Published: March 2021

This work addresses the problem of pattern analysis in networks consisting of delay-coupled identical Lur’e systems. We study a class of nonlinear systems, which, being isolated, are globally asymptotically stable. Assembling such systems into a network via time-delayed coupling may result in the change of network equilibrium stability under parameter variation in the coupling. In this work, we focus on cases where a Hopf bifurcation causes the change of stability of the network equilibrium and leads to the occurrence of oscillatory modes (patterns). Moreover, some of these patterns can co-exist for the same set of coupling parameters, which makes the analysis by means of common methods, such as the Lyapunov–Krasovskii method or the analysis of Poincaré maps, cumbersome. A numerically efficient algorithm, aiming at the computation of the oscillatory patterns occurring in such networks, is presented. Moreover, we show that our approach is able to deal with co-existing patterns, and both stable and unstable regimes can be simultaneously computed, which gives deep insight into the network dynamics. In order to illustrate the efficiency of the method, we present two examples in which the instability of the network equilibria is caused by a subcritical and a supercritical Hopf bifurcation. In addition, a bifurcation analysis of the subcritical case is performed in order to further explain the occurrence of the detected coexisting modes.
Simulations suggest that navigation software may not be as efficient as expected for city traffic
Authors: Carrasco Sebastián , Medina Pablo , Rogan José , Valdivia Juan Alejandro
Published: March 2021

We suggest a theoretical framework to study the dynamics of an open city, with cars entering at a certain rate and leaving as they reach their destinations. In particular, we assess through simulations some unexpected consequences of the massive use of GPS (global positioning system) navigation systems in the overall dynamics. One of our main interest is to identify what type of measurements would be the most relevant for an experimental study of this system, specifically, the ones useful for city traffic administrators. To do so, we solve the microdynamics using a cellular automaton model considering three different navigation strategies based on the minimization of the individual paths (unweighted strategy) or travel times (weighted strategies). Although the system is inherently stochastic, we found in our simulations an equivalent saddle-node bifurcation for all strategies where the input rate acts as a bifurcation parameter. There is also evidence of additional bifurcations for travel time minimization based strategies. Although we found that weighted strategies are more efficient in terms of car motion, there is a destabilization phenomenon that makes, in an unexpected way, a variation of the unweighted strategy more optimal at certain densities from the fuel efficiency of the overall city traffic point of view. These results bring new insight into the intrinsic dynamics of cities and the perturbations that individual traffic routing can produce on the city as a whole.
A Bitter-type electromagnet for complex atomic trapping and manipulation
Authors: Siegel J. L. , Barker D. S. , Fedchak J. A. , Scherschligt J. , Eckel S.
Published: March 2021

We create a pair of symmetric Bitter-type electromagnet assemblies capable of producing multiple field configurations including uniform magnetic fields, spherical quadruple traps, or Ioffe–Pritchard magnetic bottles. Unlike other designs, our coil allows both radial and azimuthal cooling water flows by incorporating an innovative 3D-printed water distribution manifold. Combined with a double-coil geometry, such orthogonal flows permit stacking of non-concentric Bitter coils. We achieve a low thermal resistance of 4.2(1) °C kW−1 and high water flow rate of 10.0(3) l min−1 at a pressure of 190(10) kPa.
Multifractal analysis of air and soil temperatures
Authors: Ogunjo Samuel Toluwalope , Fuwape Ibiyinka , Babatunde Rabiu A. , Oluyamo Sunday Samuel
Published: March 2021

Air and soil temperatures are important agrometeorological variables with several applications. Understanding the complex behavior of air and soil temperatures, as well as their interaction, will help in agricultural planning. Multifractal detrended fluctuation and multifractal cross-correlation analysis of air and soil temperatures were carried out in three locations (Akure, Abuja, and Bauchi) within a tropical country, Nigeria. Monthly and annual air and soil temperatures measured at 5 min intervals for a period of 1 year were obtained and analyzed for multifractality. There is evidence of seasonal dependence in the multifractal behavior of monthly soil temperature. Monthly temperatures (air and soil) were found to have higher degrees of multifractality than annual temperatures. Furthermore, latitudinal dependence was observed in the multifractal behavior of air and soil temperatures. The cross-correlation between air and soil temperatures also shows multifractality with persistence at the monthly scale and anti-persistence at the annual scale. This work has shed light on the complex relationship between air and soil temperatures, and the results will be useful in modeling the two variables.
Transition paths of marine debris and the stability of the garbage patches
Authors: Miron P. , Beron-Vera F. J. , Helfmann L. , Koltai P.
Published: March 2021

We used transition path theory (TPT) to infer “reactive” pathways of floating marine debris trajectories. The TPT analysis was applied on a pollution-aware time-homogeneous Markov chain model constructed from trajectories produced by satellite-tracked undrogued buoys from the National Oceanic and Atmospheric Administration's Global Drifter Program. The latter involved coping with the openness of the system in physical space, which further required an adaptation of the standard TPT setting. Directly connecting pollution sources along coastlines with garbage patches of varied strengths, the unveiled reactive pollution routes represent alternative targets for ocean cleanup efforts. Among our specific findings we highlight: constraining a highly probable pollution source for the Great Pacific garbage patch; characterizing the weakness of the Indian Ocean gyre as a trap for plastic waste; and unveiling a tendency of the subtropical gyres to export garbage toward the coastlines rather than to other gyres in the event of anomalously intense winds.
On the determination of the optimal parameters in the CAM model
Authors: Bianucci Marco , Mannella Riccardo
Published: March 2021

In the field of complex systems, it is often possible to arrive at some simple stochastic or chaotic Low Order Models (LOMs) exploiting the time scale separation between leading modes of interest and fast fluctuations. These LOMs, although approximate, might provide interesting qualitative insights regarding some important aspects like the average time between two extreme events. Recently, the simplest example of a LOM with multiplicative noise, namely, a linear system with a linearly state dependent noise [also called correlated additive and multiplicative (CAM) model], has been considered as archetypal for numerous phenomena that present markedly non-Gaussian statistics. We show in this paper that the determination of the parameters of a CAM model from the (few) available data is far from trivial and that the actual most likely parameters might differ substantially from the ones determined directly from a (necessarily limited) short sequence of observations. We illustrate how this problem can be tackled, at least to the extent possible, using an approach that is based on Bayes’ theorem. We shall focus on a CAM modeling the El Niño Southern Oscillation but the methodology can be extended to any phenomenon that can be described by a simplified LOM similar to the one examined here and where the available sequence of data is relatively short. We conclude that indeed a Bayesian approach can fix the problem.
Resistive-nanoindentation on gold: Experiments and modeling of the electrical contact resistance
Authors: Volpi Fabien , Rusinowicz Morgan , Comby-Dassonneville Solène , Parry Guillaume , Boujrouf Chaymaa , Braccini Muriel , Pellerin Didier , Verdier Marc
Published: March 2021

This paper reports the experimental, analytical, and numerical study of resistive-nanoindentation tests performed on gold samples (bulk and thin film). First, the relevant contributions to electrical contact resistance are discussed and analytically described. A brief comparison of tests performed on gold and on natively oxidized metals highlights the high reproducibility and the voltage-independence of experiments on gold (thanks to its oxide-free surface). Then, the evolution of contact resistance during nanoindentation is fully explained in terms of electronic transport regimes: starting from tunneling, electronic transport is then driven by ballistic conduction before ending with pure diffusive conduction. The corresponding analytical expressions, as well as their validity domains, are determined and compared with experimental data, showing excellent agreement. From there, focus is made on the diffusive regime. Resistive-nanoindentation outputs are fully described by analytical and finite-element modeling. The developed numerical framework allows a better understanding of the main parameters: it first assesses the technique capabilities (validity domains, sensitivity to tip defect, sensitivity to rheology, effect of an oxide layer, and so on), but it also validates the different assumptions made on current line distribution. Finally, it is shown that a simple calibration procedure allows a well-resolved monitoring of the contact area during resistive-nanoindentation performed on samples with complex rheologies (ductile thin film on an elastic substrate). Comparison to analytical and numerical approaches highlights the strength of resistive-nanoindentation for continuous area monitoring.
Lowest-dimensional portals to SU(N) exotics
Authors: Jeltema Tesla , Profumo Stefano , Ulbricht Jaryd F.
Published: March 2021

New matter fields charged under the strong nuclear force would have dramatic phenomenological implications. Here, we systematically explore how these new states, which we postulate belong to some representation of SU(3) of quantum chromo-dynamics, could interact with standard model fields: We analyze all lowest-dimensional “portal” operators for any SU(3) representation, and motivated by grand unification, we extend our results to SU(N) for N > 3. We provide a publicly available python code, “tessellation,” that automatically constructs said lowest-dimensional portal operators for any new exotic matter field charged under SU(N) for any N.
Insights into MnAl-C nano-twin defects by micromagnetic characterization
Authors: Gusenbauer M. , Kovacs A. , Oezelt H. , Fischbacher J. , Zhao P. , Woodcock T. G. , Schrefl T.
Published: March 2021

MnAl-C is a prominent candidate for the replacement of rare earth magnets with a moderate energy density product. Crystallographic defects have a strong effect on magnetization properties. In this work, we show the influence of twinning defects in the nanometer regime on the quality of the magnet. Standard micromagnetic simulations and computations of the saddle point configuration for magnetization reversal highlight the importance of optimizing the fraction of and reducing the width of crystallographic twin defects. Switching field distributions and the maximum possible coercive field for ideal microstructures without defects are estimated using a reduced order micromagnetic model.
Observation of 2D transport in Sn- and In-doped Bi2−xSbxTe3−ySey topological insulator
Authors: Mal Priyanath , Das Bipul , Bera G. , Rambabu P. , Turpu G. R. , Tomy C. V. , Das Pradip
Published: March 2021

Here we report magnetotransport properties of Bi2−xSbxTe3−ySey (BSTS), In- and Sn-doped BSTS single crystals, grown through modified Bridgeman technique. In- and Sn-doped BSTS single crystals show bulk insulation in temperature dependency resistivity measurements and are confirmed from the observed impurity band mediated three dimensional variable-range hopping behavior at low temperatures over virgin BSTS with metallic bulk. Magnetotransport measurements for BSTS and Sn-doped BSTS reveal a zero field sharp positive cusp and is identified as two dimensional (2D) weak antilocalization (WAL) effect, which is the consequence of π Berry phase of the carriers. For In-doped BSTS single crystals, crossover is identified from WAL to weak localization with field variation at low temperatures and also with an increase in temperature from 2 K. For all the single crystals, phase coherence lengths (lϕ) are determined by fitting low field magnetotransport data with Hikami–Larkin–Nagaoka equation. Temperature dependency of phase coherence lengths is described with 2D electron–electron (e–e) and 2D electron–phonon (e–p) interactions for virgin and In-doped BSTS single crystals while for Sn-doped BSTS specimen lϕ(T) follows T−0.53 power law.
Majorana and non-Majorana modes in a nanowire in partially proximity to a superconductor
Authors: Liu Ze-Gang , Huang Yue-Xin , Guo Guang-Can , Gong Ming
Published: March 2021

We investigate the Majorana and non-Majorana modes in a nanowire in partial proximity to a superconductor, in which the gapped superconductor will play different roles in different topological regimes. In the gapped topological superconducting phase, it plays the role of a topological barrier, which confines some localized edge modes in the quantum dot (QD) region. The probability for the wave function in this region can approach unity by tuning the system parameters. These low-lying localized modes exhibit linear spectra with equal energy level spacing, with eigenvalues εn=vFnπ/(2L), where vF is the Fermi velocity, L is the size of the QD region, and n∈Z. We demonstrate these features using a spinless nanowire in proximity to a p-wave superconductor and a spin–orbit coupled semiconductor nanowire in proximity to a s-wave superconductor. A simple picture is proposed to understand the behavior of these results. However, in the trivial superconducting phase when both bands are occupied in the spin–orbit coupled mode, we observe some non-Majorana modes, with complicated low-lying excited spectra, which resembles that reported in experiments. These differences are rooted deeply in the bulk-edge correspondence. These observations may be able to facilitate the identification of Majorana zero modes in experiments.
Cavity-modulated ionization potentials and electron affinities from quantum electrodynamics coupled-cluster theory
Authors: DePrince A. Eugene
Published: March 2021

Quantum electrodynamics coupled-cluster (QED-CC) theory is used to model vacuum-field-induced changes to ground-state properties of a series of sodium halide compounds (NaX, X = F, Cl, Br, and I) strongly coupled to an optical cavity. Ionization potentials (IPs) and electron affinities (EAs) are presented, and it is demonstrated that EAs are easily modulated by cavity interactions, while IPs for these compounds are far less sensitive to the presence of the cavity. EAs predicted by QED-CC can be reduced by as much as 0.22 eV (or ≈50%) when considering experimentally accessible coupling parameters.
Damköhler number scaling of active cascade effects in turbulent premixed combustion
Authors: MacArt Jonathan F. , Mueller Michael E.
Published: March 2021

Effects of combustion heat release on turbulent velocity and scalar statistics are investigated as a function of the Damköhler number using three direct numerical simulation databases of spatially developing turbulent premixed jet flames. At low Karlovitz numbers, where heat-release effects dominate turbulent kinetic energy budgets, their relative significance scales with the integral Damköhler number in a priori Reynolds-Averaged Navier–Stokes (RANS) statistics and the filter Damköhler number in Large Eddy Simulation (LES). The Damköhler-number scaling of counter-gradient transport in this regime follows theoretical arguments underpinning linear-algebraic turbulence models, which explains their efficacy at low Karlovitz numbers. Conversely, at moderate Karlovitz numbers, LES subfilter turbulence is more strongly influenced by heat-release effects than the analogous large-scale RANS turbulence. This is consistent with the notion of an “active cascade,” which postulates that heat-release-induced volumetric expansion competes on intermediate scales with classical forward-cascade energy transfer. LES exposes these dynamics as dominant subfilter-scale physics, unlike in RANS, where they are secondary to the effects of mean-shear production at the large scales. The significance of subfilter-scale interactions is promoted by the LES filter itself, which modifies the RANS spectral basis by incorporating local flame-normal averaging. This is highlighted by comparing LES fields obtained using a 3D filter to those using a modified 2D filter, excluding the flame-normal direction, which significantly reduces the apparent influence of heat-release effects but is not representative of LES in practice. The subfilter modeling challenges posed by these distinctions at moderate Karlovitz numbers and order-unity Damköhler numbers remain to be understood.
The phase space distribution of confined fluids under shear is not fractal
Authors: Maffioli Luca , Clisby Nathan , Frascoli Federico , Todd B. D.
Published: March 2021

We analyze the phase-space compression, characteristic of all deterministic, dissipative systems for an inhomogeneous boundary-driven shear fluid via nonequilibrium molecular dynamics simulations. We find that, although the full system undergoes a phase space contraction, the marginal distribution of the fluid particles is described by a smooth, volume preserving probability density function. This is the case for most thermodynamic states of physical interest. Hence, we show that the models currently employed to investigate inhomogeneous fluids in a nonequilibrium steady state, in which only walls are thermostatted, generate a non-singular distribution for the fluid.
Anomalous Hall and Nernst effects in ferrimagnetic Mn4N films: Possible interpretations and prospects for enhancement
Authors: Isogami Shinji , Masuda Keisuke , Miura Yoshio , Rajamanickam Nagalingam , Sakuraba Yuya
Published: March 2021

Ferrimagnetic Mn4N is a promising material for heat flux sensors, based on the anomalous Nernst effect (ANE), because of its sizeable uniaxial magnetic anisotropy (Ku) and low saturation magnetization (Ms). We experimentally and theoretically investigated the ANE and anomalous Hall effect in sputter-deposited Mn4N films. It was revealed that the observed negative anomalous Hall conductivity (σxy) could be explained by two different coexisting magnetic structures, that is, a dominant magnetic structure with high Ku, contaminated by another structure with negligible Ku, owing to an imperfect degree of order of N. The observed transverse thermoelectric power (SANE) of +0.5 μV/K at 300 K yielded a transverse thermoelectric coefficient (αxy) of +0.34 A/(m · K), which was smaller than the value predicted from the first-principles calculation. The interpretation for αxy based on the first-principles calculations led us to conclude that the realization of single magnetic structure with high Ku and optimal adjustment of the Fermi level are promising approaches to enhance SANE in Mn4N through the sign reversal of σxy and the enlargement of αxy up to a theoretical value of 1.77 A/(m · K).
Revisiting the memory capacity in reservoir computing of directed acyclic network
Authors: Han Xinyu , Zhao Yi , Small Michael
Published: March 2021

Reservoir computing (RC) is an attractive area of research by virtue of its potential for hardware implementation and low training cost. An intriguing research direction in this field is to interpret the underlying dynamics of an RC model by analyzing its short-term memory property, which can be quantified by the global index: memory capacity (MC). In this paper, the global MC of the RC whose reservoir network is specified as a directed acyclic network (DAN) is examined, and first we give that its global MC is theoretically bounded by the length of the longest path of the reservoir DAN. Since the global MC is technically influenced by the model hyperparameters, the dependency of the MC on the hyperparameters of this RC is then explored in detail. In the further study, we employ the improved conventional network embedding method (i.e., struc2vec) to mine the underlying memory community in the reservoir DAN, which can be regarded as the cluster of reservoir nodes with the same memory profile. Experimental results demonstrate that such a memory community structure can provide a concrete interpretation of the global MC of this RC. Finally, the clustered RC is proposed by exploiting the detected memory community structure of DAN, where its prediction performance is verified to be enhanced with lower training cost compared with other RC models on several chaotic time series benchmarks.
Micromagnetic study of sphericity effect in bulk permanent magnets
Authors: Kim C. S. , Ding S. L. , Kim J. H. , Yun C. , Yang W. Y. , Han J. Z. , Liu S. Q. , Du H. L. , Wang C. S. , Yang J. B.
Published: March 2021

The sphericity, κ, is introduced to describe the morphology of the magnetic grains. The effect of κ on the magnetic properties of rare earth-transition metal (RE-TM) permanent magnets was investigated using the micromagnetic simulation, where randomly aligned, irregular-shaped grains with ferromagnetic/non-ferromagnetic grain boundary (GB) phases were considered. For the simulated RE-TM systems, the coercivity increases significantly with the increase in κ. In particular, with 10 nm thick non-ferromagnetic GB phase, the coercivity, 1.74 MA/m, for к = 0.9 increases by 22% compared to 1.43 MA/m for к = 0.6 in the Nd2Fe14B system. Among the simulated materials, the SmCo5 system displays the largest increment in coercivity, increasing by 0.82 MA/m from 7.61 MA/m for к = 0.6 to 8.43 MA/m for к = 0.9. Magnetization reversal patterns under different external fields indicate that the dependence of coercivity on κ is attributed to the formation of local reversals at different regions and mechanisms of reversal propagation. Meanwhile the effect of κ cannot be neglected even at elevated temperatures. The simulated results of (Dy0.47Nd0.53)2Fe14B systems with the non-ferromagnetic GB layer of 4 nm at a temperature of 450 K show that the coercivity for к = 0.9 (1.88 MA/m) increased by 23% compared with that of к = 0.6 (1.52 MA/m). Our study demonstrates that the sphericity can be used as a key parameter to design high-coercivity RE-TM magnets.
Configuration interaction trained by neural networks: Application to model polyaromatic hydrocarbons
Authors: Ghosh Sumanta K. , Rano Madhumita , Ghosh Debashree
Published: March 2021

The main bottleneck of a stochastic or deterministic configuration interaction method is determining the relative weights or importance of each determinant or configuration, which requires large scale matrix diagonalization. Therefore, these methods can be improved significantly from a computational standpoint if the relative importance of each configuration in the ground and excited states of molecular/model systems can be learned using machine learning techniques such as artificial neural networks (ANNs). We have used neural networks to train the configuration interaction coefficients obtained from full configuration interaction and Monte Carlo configuration interaction methods and have tested different input descriptors and outputs to find the more efficient training techniques. These ANNs have been used to calculate the ground states of one- and two-dimensional Heisenberg spin chains along with Heisenberg ladder systems, which are good approximations of polyaromatic hydrocarbons. We find excellent efficiency of training and the model this trained was used to calculate the variational ground state energies of the systems.
A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation
Authors: Woźniak Aleksander P. , Lesiuk Michał , Przybytek Michał , Efimov Dmitry K. , Prauzner-Bechcicki Jakub S. , Mandrysz Michał , Ciappina Marcelo , Pisanty Emilio , Zakrzewski Jakub , Lewenstein Maciej , Moszyński Robert
Published: March 2021

A precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.
Pathogenic LRRK2 regulates ciliation probability upstream of tau tubulin kinase 2 via Rab10 and RILPL1 proteins
Authors: Sobu Yuriko , Wawro Paulina S. , Dhekne Herschel S. , Yeshaw Wondwossen M. , Pfeffer Suzanne R.
Published: March 2021

Significance

Mutations that activate LRRK2 protein kinase cause Parkinson's disease. LRRK2 phosphorylates a subset of Rab GTPases, in particular Rab8 and Rab10. We show here details related to the mechanism by which Rab10 phosphorylation blocks initiation of cilia formation, fundamental information related to how pathogenic LRRK2 interferes with normal cell physiology.
Local induction of bladder Th1 responses to combat urinary tract infections
Authors: Wu Jianxuan , Bao Chunjing , Reinhardt R. Lee , Abraham Soman N.
Published: March 2021

Significance

Urinary tract infections (UTIs) are the second most common bacterial infections. Caring for UTI patients is very difficult and often perplexing. We typically view our immune system as an adaptive line of defense that becomes more responsive to specific pathogens after episodes of infection. However, the opposite is seen in these patients, in whom each infection actually increases the risk of a subsequent infection. Our group recently identified the underlying basis as a highly Th2-biased response in bladder that inhibits Th1-mediated bacterial clearance. To resolve this situation, we investigated whether immunizing mice intravesically with bacterial antigens combined with a Th1-skewing adjuvant (CpG) would evoke a more balanced and protective immune response.
Single-cell analyses identify circulating anti-tumor CD8 T cells and markers for their enrichment
Authors: Pauken Kristen E. , Shahid Osmaan , Lagattuta Kaitlyn A. , Mahuron Kelly M. , Luber Jacob M. , Lowe Margaret M. , Huang Linglin , Delaney Conor , Long Jaclyn M. , Fung Megan E. , Newcomer Kathleen , Tsai Katy K. , Chow Melissa , Guinn Samantha , Kuchroo Juhi R. , Burke Kelly P. , Schenkel Jason M. , Rosenblum Michael D. , Daud Adil I. , Sharpe Arlene H. , Singer Meromit
Published: March 2021

The ability to monitor anti-tumor CD8+ T cell responses in the blood has tremendous therapeutic potential. Here, we used paired single-cell RNA and TCR sequencing to detect and characterize “tumor-matching” (TM) CD8+ T cells in the blood of mice with MC38 tumors or melanoma patients using the TCR as a molecular barcode. TM cells showed increased activation compared with nonmatching T cells in blood and were less exhausted than matching cells in tumors. Importantly, PD-1, which has been used to identify putative circulating anti-tumor CD8+ T cells, showed poor sensitivity for identifying TM cells. By leveraging the transcriptome, we identified candidate cell surface markers for TM cells in mice and patients and validated NKG2D, CD39, and CX3CR1 in mice. These data show that the TCR can be used to identify tumor-relevant cells for characterization, reveal unique transcriptional properties of TM cells, and develop marker panels for tracking and analysis of these cells.
Advancing ambulatory pharmacy practice through a crisis: Objectives and strategies used in an ambulatory care action team’s response to the COVID-19 pandemic
Authors: Do Tina , Luon Steph , Boothe Kimberly , Stutsky Martha , Renauer Marie
Published: March 2021

Purpose

The objectives and strategies used by an ambulatory care action team operating within a large health system’s pharmacy incident command structure during the initial response to the coronavirus disease 2019 (COVID-19) pandemic are discussed.

In a time of crisis, a pharmacy ambulatory action team was formed to provide ambulatory clinical pharmacy expertise and meet an immediate and ongoing need to limit nonemergent care during the COVID-19 pandemic. By building a strong communication infrastructure and partnership with ambulatory care providers, clinic medical and operational leaderships, clinical laboratory staff, and infusion centers, the team was able to swiftly execute solutions and respond to new issues and requests. Ambulatory care pharmacy practice continued to advance through provision of services to vulnerable patient populations with chronic conditions that were anticipated to experience gaps in care management during the COVID-19 pandemic. These efforts resulted in expansion of pharmacists’ involvement in collaborative drug therapy management, support of patients’ transition from in-clinic injection to home self-administration, provision of medication assistance support, and management of 1,300 patients via protocol-based warfarin management. Additionally, ambulatory pharmacy services in 15 primary care, anticoagulation, and specialty clinic sites were transitioned to telehealth. The ambulatory action team also implemented several strategies to manage medication therapy associated with COVID-19–related shortages and implemented electronic decision support to guide prescribing of hydroxychloroquine and azithromycin.

Conclusion

Building a strong communication infrastructure and a pharmacy ambulatory action team were essential to respond to a crisis and continue ambulatory clinical pharmacy services expansion.
Both Nonsmoking Youth and Smoking Adults Like Sweet and Minty E-liquid Flavors More Than Tobacco Flavor
Authors: Krüsemann Erna J Z , van Tiel Loes , Pennings Jeroen L A , Vaessen Wim , de Graaf Kees , Talhout Reinskje , Boesveldt Sanne
Published: March 2021

Smokers may reduce their health risk by switching to electronic cigarette (e-cigarette) use. As e-cigarettes are not harmless, concerns exist about e-cigarette use by nonsmokers and youth. E-liquids are available in many different flavors that increase sensory appeal. Flavor preferences may differ between user groups, which could open doors for product regulation. We investigated which e-liquid flavors are attractive to specific user groups by comparing liking between adolescent nonsmokers (n = 41; mean age 16.9 ± 0.8), young adult nonsmokers (n = 42; mean age 22.7 ± 1.7), and adult smokers (n = 56; mean age 39.7 ± 11.1). Participants smelled tobacco- (n = 6) and nontobacco (n = 24)-flavored e-liquids and rated liking on a 9-point labeled hedonic scale, and familiarity, overall intensity, perceived sweetness, perceived bitterness, and irritation of the odors on a 100-unit Visual Analog Scale. Mean liking ranged from 2.3 (whiskey) to 6.7 (peppermint). Within all groups, the typically sweet and minty flavors (e.g., wine gum, watermelon, peppermint, menthol) were liked significantly more than the tobacco-flavored e-liquids. The set of tobacco-flavored e-liquids was significantly, but slightly, less disliked by adult smokers (3.9 ± 0.2) than adolescent (3.1 ± 0.3) and young adult (3.4 ± 0.3) nonsmokers (P < 0.001). No between-group differences were observed for sweet and minty flavors. Liking correlated significantly positively with odor sweetness (R = 0.49) and familiarity (R = 0.48) and negatively with odor bitterness (R = −0.58), irritation (R = −0.47), and overall intensity (R = −0.27). Thus, sweet- and minty-flavored e-liquids are liked equally by young nonsmokers and adult smokers, and more than tobacco flavors. Banning all flavors except tobacco will likely reduce e-cigarette appeal; potentially more for young nonsmokers than adult smokers.
The “Indirect Support” Loophole in the New SOE Norms: An Intentional Choice or Inadvertent Mistake?
Authors: Lee Jaemin
Published: March 2021

Recent trade agreements contain new norms on SOEs which set forth detailed provisions to regulate a wide range of activities of contracting parties’ governments and their SOEs. Given the increasing global attention to the operation of SOEs in international trade and investment, and their significant influence, the new norms provide important legal guidance and a useful platform for future discussions in this area. These new norms include: restriction of governmental support for SOEs, restriction of SOEs’ support for other SOEs, and prevention of anti-competitive activities of SOEs, among others. While arguably offering a first stride in the right direction, the new norms also include critical ambiguities and uncertainties as regards key concepts and principles, which could potentially render full implementation of the norms elusive and complex. In particular, these new norms contain provisions that could lead to significant circumvention due to its critical “ASCM-minus” approach. This loophole is arguably capable of undermining the basic objectives of the new SOE norms. This approach should be reconsidered in future formulation of SOE norms in trade agreements including a prospective new agreement on this issue at the WTO.
Analyses of ‘change scores’ do not estimate causal effects in observational data
Authors: Tennant Peter W G , Arnold Kellyn F , Ellison George T H , Gilthorpe Mark S
Published: March 2021

Background

In longitudinal data, it is common to create ‘change scores’ by subtracting measurements taken at baseline from those taken at follow-up, and then to analyse the resulting ‘change’ as the outcome variable. In observational data, this approach can produce misleading causal-effect estimates. The present article uses directed acyclic graphs (DAGs) and simple simulations to provide an accessible explanation for why change scores do not estimate causal effects in observational data.

Methods

Data were simulated to match three general scenarios in which the outcome variable at baseline was a (i) ‘competing exposure’ (i.e. a cause of the outcome that is neither caused by nor causes the exposure), (ii) confounder or (iii) mediator for the total causal effect of the exposure variable at baseline on the outcome variable at follow-up. Regression coefficients were compared between change-score analyses and the appropriate estimator(s) for the total and/or direct causal effect(s).

Results

Change-score analyses do not provide meaningful causal-effect estimates unless the baseline outcome variable is a ‘competing exposure’ for the effect of the exposure on the outcome at follow-up. Where the baseline outcome is a confounder or mediator, change-score analyses evaluate obscure estimands, which may diverge substantially in magnitude and direction from the total and direct causal effects.

Conclusion

Future observational studies that seek causal-effect estimates should avoid analysing change scores and adopt alternative analytical strategies.