bluuebunny/crossref_metadata_2025 huggingface dataset:
Giant enhancement of third harmonic generation via guided mode resonances in notched silicon waveguides
Authors: Wang Ziyu , Zhao Qiming , Tang Wenjie , Gao Yajun , He Jie , Zhu Yi , Wang Shuxian , Yu Haohai , Peng Ruwen , Wang Mu
Published: March 2024

We report a giant enhancement of the third harmonic generation (THG) at 343 nm by periodically notched silicon waveguide arrays supporting guided mode resonances (GMRs) at 1030 nm. Maximum efficiency of the third harmonic generation η = 7.71 × 10−5 is achieved with a peak pump power density of 5.31 GW/cm2. The enhancement factor of the THG from the GMR metasurface reaches up to 1.3 × 107 compared to a flat silicon film with the same thickness. This observation demonstrates a promising approach to design high-efficiency nonlinear optical metasurfaces.
Shock formation in flowing plasmas by temporally and spatially smoothed laser beams
Authors: Ludwig J. D. , Hüller S. , Rose H. A. , Bruulsema C. , Farmer W. , Michel P. , Milder A. L. , Swadling G. F. , Rozmus W.
Published: March 2024

The cumulative impact of multiple laser speckles on a supersonic plasma flow across optically smoothed laser beams is investigated. The bending of laser beams caused by ponderomotive laser–plasma coupling, together with flow, leads to plasma a momentum-conserving response that results in a deceleration of the flow. Once the flow velocity decreases to a subsonic level, the action of the laser beams can generate a shock within the plasma. This scenario has been predicted theoretically and confirmed by hydrodynamic simulations. The conditions of shock generation are given in terms of the ponderomotive pressure, speckle size, and the flow velocity. The nonlinear properties of the shocks are analyzed using Rankine–Hugoniot relations. According to linear theory, temporally smoothed beams exhibit a higher threshold for shock generation. Numerical simulations with beams that are smoothed by spectral dispersion compare well with the linear theory results, diverging only in the nonlinear regime. The conditions necessary for shock generation and their effects on the laser–plasma coupling in the inertial confinement fusion experiments are also discussed.
Energetic and dynamic characterization of pollutant dispersion in varied building layouts through an augmented analysis procedure
Authors: Fu Yunfei , Li Cruz Y. , Zhao Zhihang , Zhang Bingchao , Tse K. T. , Mak Cheuk Ming , Chen Zengshun , Feng Xinxin , Lin Xisheng , Li Wenxin , Lin Chongjia
Published: March 2024

This work presents a post-data analysis procedure, namely, proper orthogonal decomposition (POD)–dynamic mode decomposition (DMD)–discrete Fourier transform analysis, for evaluating the dominant features of the flow fields from both energetic and dynamic perspectives. The large-eddy simulation (LES) was first employed to reproduce the flow field surrounding three types of building layouts. Subsequently, both POD and DMD were conducted according to LES simulation results. The extracted modes were classified into three types based on the POD and DMD: Type-1 mode: energetically and dynamically significant mode, Type-2 mode: energetically significant and dynamically insignificant mode, and Type-3 mode: energetically insignificant and dynamically significant mode. The findings indicate that Type-1 mode governs the primary velocity field and the predominant vortex patterns observed at the rear of the building arrays, as the reduction of inter-building widths leads to a shorter flow separation region. Type-2 mode is characterized by the presence of small-scale vortices and the high turbulent kinetic energy region, which periodically triggers pollutant increase in the vicinity of structures. Type-3 mode demonstrates a minimal energetic influence on the flow field; nevertheless, it significantly contributes to the consistent build-up of pollutants within the far-wake region. The present study also investigates the predominant coherent structures of flow fields concerning various building layouts and highlights the influence of passage widths on the efficiency of pollutant removal. This comprehensive analysis enables a systematic exploration of flow patterns within various building layouts, offering potential solutions for pollutant dispersion challenges in metropolitan areas.
Avoiding matrix exponentials for large transition rate matrices
Authors: Pessoa Pedro , Schweiger Max , Pressé Steve
Published: March 2024

Exact methods for the exponentiation of matrices of dimension N can be computationally expensive in terms of execution time (N3) and memory requirements (N2), not to mention numerical precision issues. A matrix often exponentiated in the natural sciences is the rate matrix. Here, we explore five methods to exponentiate rate matrices, some of which apply more broadly to other matrix types. Three of the methods leverage a mathematical analogy between computing matrix elements of a matrix exponential process and computing transition probabilities of a dynamical process (technically a Markov jump process, MJP, typically simulated using Gillespie). In doing so, we identify a novel MJP-based method relying on restricting the number of “trajectory” jumps that incurs improved computational scaling. We then discuss this method’s downstream implications on mixing properties of Monte Carlo posterior samplers. We also benchmark two other methods of matrix exponentiation valid for any matrix (beyond rate matrices and, more generally, positive definite matrices) related to solving differential equations: Runge–Kutta integrators and Krylov subspace methods. Under conditions where both the largest matrix element and the number of non-vanishing elements scale linearly with N—reasonable conditions for rate matrices often exponentiated—computational time scaling with the most competitive methods (Krylov and one of the MJP-based methods) reduces to N2 with total memory requirements of N.
Computational screening of silver-based single-atom alloys catalysts for CO2 reduction
Authors: Neto Marionir M. C. B. , Verga Lucas G. , Da Silva Juarez L. F. , Galvão Breno R. L.
Published: March 2024

Electrocatalytically reducing CO2 into value-added products is a challenging but promising process. Catalysts have been proposed to reduce the potential necessary for the reaction to occur, among which single-atom alloys (SAAs) are particularly promising. Here, we employ density functional theory calculations and the computational electrode model to predict whether silver-based SAAs have the potential to be effective electrocatalysts to convert CO2 into C1 products. We take into account surface defects by using the Ag(211) surface as a model. We also verify whether the proposed materials are prone to OH poisoning or enhance the competing hydrogen evolution reaction. Our calculations predict that these materials show weak mixing between the host and the dopant, characterized by a sharp peak in the density of states near the Fermi energy, except when copper (also a coinage metal) is used as the dopant. This affects the adsorption energy of the different intermediate molecules, yielding different reaction profiles for each substrate. As non-doped silver, copper-doped SAA tends to spontaneously desorb carbon monoxide (CO) instead of proceeding with its reduction. Other elements of the fourth period (Fe, Co, and Ni) tend to bind to the CO molecule but do not favor more reduced products. These metals also tend to enhance the hydrogen evolution reaction. On the contrary, we show that the Ir and Rh dopants have significant potential as electrocatalysts, which favors the reduction of CO over its desorption while also suppressing the hydrogen evolution reaction at potentials lower than those required by copper. They have also been shown to not be prone to poisoning by OH radicals.
Phase modulation by quantum gates of two microwave pulses in the framework of spin-boson model
Authors: Chen Cheng , Zeng Jiarui , Yao Yao
Published: March 2024

As one of the most successful platforms of quantum control, trapped ions can be modulated by sequential microwave pulses to realize high-fidelity quantum logic gates, and dephasing noise may lead to invalidation of phase locking. In this work, we utilize the Dirac–Frenkel time-dependent variational approach with Davydov ansatz to simulate spin echo dynamics in the framework of spin-boson model. As the essential modulation parameters, pulse duration and waiting time have been comprehensively investigated to optimize the phase gates by two microwave pulses. We find that, as spin orientation undergoes periodic changes, the phase difference by acting one and two pulses exhibits spontaneous locking following time evolution, which indicates the robustness of the quantum phase gates. Spectrum of the environmental noise that is appropriate for the phase locking is also determined.
Impact of Se concentration and distribution on topological transition in FeTe1−
xSex crystals
Authors: Wang Jinying , Klimeck Gerhard
Published: March 2024

A topological phase transition in high-temperature superconductor FeTe1−xSex, occurring at a critical range of Se concentration x, underlies their intrinsic topological superconductivity and emergence of Majorana states within vortices. However, how Se concentration and distribution determine the electronic states, particularly the presence or absence of Majorana states, in FeTe1−xSex remains unclear. In this study, we combine density functional theory calculations with pz–dxz/yz-based analysis and Wannier-based Hamiltonian analysis to systematically explore the electronic structures of diverse FeTe1−xSex compositions. Our investigation reveals a nonlinear variation of the spin–orbit coupling (SOC) gap between pz and dxz/yz bands in response to the Se concentration x, with the maximum gap occurring at x = 0.5. The pz–pz and dx2−y2–pz interactions are found to be critical for pd band inversion. Furthermore, the distribution of Se significantly modulates the SOC gap, thereby influencing the emergence of Majorana states within local vortices.
Acoustic radiation of bubble clusters with different volume fractions
Authors: Deng Fuqiang , Zhao Di , Zhang Lingxin , Li Yang
Published: March 2024

Cavitation noise, mainly from bubble cluster collapse, is a primary source of noise in underwater equipment. This study aims to elucidate the acoustic characteristics of bubble clusters with varying volume fractions (0.002%–43%), thereby illuminating the noise patterns generated during bubble cluster collapse. With the direct numerical simulation (DNS) method, we simulate the collapse of bubble clusters containing 352 vapor bubbles. Far-field sound pressure was calculated by using the Farassat 1 A integral solution of the Ffowcs Williams–Hawkings (FW–H) equation. The results show that when the volume fraction of bubble clusters is greater than 20%, the higher the volume fraction, the closer the far-field sound pressure radiated by its collapse is to that of the equivalent bubble (whose volume is equal to the volume of the bubble cluster), and when the volume fraction is greater than 30%, the sound pressure of the bubble cluster is basically the same as that of the equivalent bubble. Furthermore, when the volume fraction of bubble clusters is less than 1%, the lower the volume fraction is, the closer the sound pressure obtained through the superposition of a single bubble (each with an initial radius equal to that within clusters and in a free field) is to that of bubble clusters, and when the volume fraction is less than 0.1%, the bubble clusters' sound pressures agree with those obtained through superposition. This study reveals the far-field noise pattern generated by the collapse of bubble clusters, providing a theoretical basis for the prediction of cavitation noise.
Deep smoothness weighted essentially non-oscillatory method for two-dimensional hyperbolic conservation laws: A deep learning approach for learning smoothness indicators
Authors: Kossaczká Tatiana , Jagtap Ameya D. , Ehrhardt Matthias
Published: March 2024

In this work, we enhance the fifth-order Weighted Essentially Non-Oscillatory (WENO) shock-capturing scheme by integrating deep learning techniques. We improve the established WENO algorithm by training a compact neural network to dynamically adjust the smoothness indicators within the WENO scheme. This modification boosts the accuracy of the numerical results, particularly in proximity to abrupt shocks. Notably, our approach eliminates the need for additional post-processing steps, distinguishing it from previous deep learning-based methods. We substantiate the superiority of our new approach through the examination of multiple examples from the literature concerning the two-dimensional Euler equations of gas dynamics. Through a thorough investigation of these test problems, encompassing various shocks and rarefaction waves, our novel technique consistently outperforms the traditional fifth-order WENO scheme. This superiority is especially evident in cases where numerical solutions exhibit excessive diffusion or overshoot around shocks.
Sustained AhR activity programs memory fate of early effector CD8
+
T cells
Authors: Zhang Huafeng , Yang Zhuoshun , Yuan Wu , Liu Jincheng , Luo Xiao , Zhang Qian , Li Yonggang , Chen Jie , Zhou Yabo , Lv Jiadi , Zhou Nannan , Ma Jingwei , Tang Ke , Huang Bo
Published: March 2024

Identification of mechanisms that program early effector T cells to either terminal effector T (T
eff
) or memory T (T
m
) cells has important implications for protective immunity against infections and cancers. Here, we show that the cytosolic transcription factor aryl hydrocarbon receptor (AhR) is used by early T
eff
cells to program memory fate. Upon antigen engagement, AhR is rapidly up-regulated via reactive oxygen species signaling in early CD8
+
T
eff
cells, which does not affect the effector response, but is required for memory formation. Mechanistically, activated CD8
+
T cells up-regulate HIF-1α to compete with AhR for HIF-1β, leading to the loss of AhR activity in HIF-1α
high
short-lived effector cells, but sustained in HIF-1α
low
memory precursor effector cells (MPECs) with the help of autocrine IL-2. AhR then licenses CD8
+
MPECs in a quiescent state for memory formation. These findings partially resolve the long-standing issue of how T
eff
cells are regulated to differentiate into memory cells.
Eponyms in physics: useful tools and cultural heritage
Authors: Gabovich Alexander M , Kuznetsov Volodymyr I
Published: March 2024

The recent proposition to eliminate eponyms from physical publications is discussed. The role of eponyms in research and education is analyzed. We show that eponyms constitute an integral part of physical texts and ensure the continuity of scientific research. Their proposed elimination is dangerous for science and the entire human culture and must be rejected.
Rotational phase transitions in antifluorite-type osmate and iridate compounds
Authors: Bertin A , Kiefer L , Becker P , Bohatý L , Braden M
Published: March 2024

We present temperature-dependent single-crystal diffraction results on seven antifluorite-type

A
2

M
e

X
6

compounds with Me = Os or Ir: K2OsCl6, A
2OsBr6 with A = K, Rb, Cs and NH4, and K2IrX
6 with X = Cl and Br. The structural transitions in this family arise from MeX
6 octahedron rotations that generate a rich variety of symmetries depending on the rotation axis and stacking schemes. In order to search for local distortions in the high-symmetry phase we perform refinements of anharmonic atomic displacement parameters with comprehensive data sets. Even at temperatures close to the onset of structural distortions, these refinements only yield a small improvement indicating only small anharmonic effects. The phase transitions in these antifluorites are essentially of displacive character. However, some harmonic displacement parameters are very large reflecting soft phonon modes with the softening covering large parts of the Brillouin zone. The occurrence of the rotational transitions in the antifluorite-type family can be remarkably well analyzed in terms of a tolerance factor of ionic radii.
Experimental determination of the hafnium L-subshell fundamental parameters using the holistic approach
Authors: Wauschkuhn Nils , Gundlach Heiko , Hönicke Philipp
Published: March 2024

By employing the recently demonstrated new holistic approach, the atomic fundamental parameters (FPs) of the three Hf-L subshells were experimentally determined using the radiometrically calibrated instrumentation of the Physikalisch-Technische Bundesanstalt. The Coster–Kronig factors, the L-subshell fluorescence yields, the L-subshell Auger yields, the subshell-photoionization cross sections, and the subshell fluorescence production cross sections were determined by means of photon energy dependent x-ray fluorescence and transmission measurements. The recently demonstrated new holistic evaluation approach allows to determine the FPs with significantly lower uncertainties as compared to the former data evaluation scheme, where only a limited regime of incident photon energies is being probed and the data evaluation scheme is performed in a sequential manner.
Advances of embedded resistive random access memory in industrial manufacturing and its potential applications
Authors: Wang Zijian , Song Yixian , Zhang Guobin , Luo Qi , Xu Kai , Gao Dawei , Yu Bin , Loke Desmond , Zhong Shuai , Zhang Yishu
Published: March 2024

Highlights

Below are the highlights of this review:

This paper explores embedded RRAM development, parameters, and integration tech compatible with CMOS, highlighting advantages in embedded systems and its potential impact on chip process nodes.

This paper introduces recent industry developments in embedded RRAM, featuring research from companies like Intel and TSMC, showcasing significant commercial application potential.

This paper discusses embedded RRAM’s progress beyond storage, exploring potential applications in FPGA, MCU, CIM, and Neuromorphic Computing, along with challenges and future prospects.
Numerical study of nonlinear interaction of the guided wave due to breathing type debonding in stiffened panel
Authors: Kumar Abhijeet , Banerjee Sauvik , Guha Anirban
Published: March 2024

The common tool for assessment of breathing-type debonding in metallic or composite structures is nonlinear guided wave-based technique. The past studies show that with debonding size, the strength of the nonlinearity does not exhibit strictly increasing or decreasing trends, or that the monocity is valid up to a certain size limit of debonding. This paper presents the study of non-linear interaction of guided waves in the debonding interface of a metallic stiffened panel. The study attempts to establish a relationship between the contact energy generated by the contact acoustic nonlinearity (CAN) at the debonding interface and the associated nonlinearity strength for various debonding sizes at various excitation frequencies. A numerical model of the stiffened panels is developed in three-dimensional finite element (FE) and validated with experiments for the study of interaction of nonlinear guided waves. The validated FE model is used to conduct studies on nonlinear interactions in debonding. The outcome of this study contributes to a better understanding of how guided waves can be used to effectively assess the debonding in metallic stiffened panels by considering non-linear interactions at the debonding interface. The study also provides insights into a more accurate and consistent quantification of the debonding using higher harmonic signals and contact energy produced by non-linear interactions.
A Revit-Midas/Civil conversion approach for bridge superstructures analysis
Authors: Li Jian , Song Haoxin , Zhou Zhenwei , Yang Chao , Wang Liyu , Li Hongtao
Published: March 2024

In this study, a model conversion method that combined Revit with Midas Civil software was proposed to improve the modeling efficiency and accuracy of finite element calculations for a large bridge structure. The secondary development program was established using the Visual Studio 2022 platform, which was used to convert the model information. A model conversion interface was created by extracting, screening, and then sorting the geometric information of the business information model and generating a Midas Civil Text file. This interface served as a link between Revit and Midas Civil, specifically for the bridge superstructure. The feasibility and reliability of the proposed model conversion method was confirmed using a single-box three-cell Box-girder bridge. The results demonstrated that the model conversion method transfered the Revit model information successfully to a Midas Civil structural analysis model, thereby significantly enhancing the efficiency and accuracy of the finite element modeling of a complex bridge superstructure.
Gas turbine aero engine fault detection using Geo-TLSVM and digital twin with multimodal data analysis
Authors: Tadepalli Naga Venkata Rama Subbarao , Koona Ramji
Published: March 2024

DT is the digital representation of physical systems to simulate real situations in a digital version. Here, the DT of the GaT-AE is created for the Fault Detection (FD) process. The GaT is a type of internal combustion engine that uses the air as the working fluid to propel the flight. However, the incorporation of big data analysis in the DT model is challenging in previous works. So, a multimodal GaT-AE fault identification system is proposed. First, the 3D print of the GaT-AE is created. Then, the data is collected from both built-in sensors and DT. Afterward, the multimodal data is pre-processed and balanced by using HT-QNN and QADASYN, respectively. Next, the features are processed by GT-PFS, and finally, the faults are detected by Geo-TLSVM. The analysis proved that the developed model outperformed the other state-of-the-art model with its effective FD rate of 97.24%.
Multifunctional applications of passive solar stills in water treatment: an eco-friendly approach
Authors: Singh Krishn Pratap , Dixit Abhishek , Singh Deepesh
Published: March 2024

Conventional raw water treatment methods are expensive and require a sufficient energy supply for their operations. In remote and rural areas, these conventional methods are feasible due to a poor economy and interrupted power supply. This study provides a sustainable approach to treating raw water using solar energy and phase change material (PCM). Passive solar stills (SS) are sufficient to treat water in the presence of solar radiation, and we can increase the yield and quality of distillate water by using calcium chloride hexahydrate as a phase change material. Moreover, PCM-based solar still is also advanced by adding activated charcoal (AC) for the removal of fluoride from the raw water. The efficiency of the solar still was assessed for the eight parameters: yield (Y), fluoride (F), total dissolved solids (TDS), electrical conductivity (EC), pH, total alkalinity (TA), total hardness (TH), chloride (Cl). Through the number of water quality assessments, it was found that SS with PCM can reduce (%) the TDS (85%–100%), EC (90%–100%), pH (0%–15%), TH (90%–95%), TA (75%–90%), and Cl (80%–100%) and can increase the yield by 10%–15%. SS with PCM and AC also showed good removal of F from raw water. In addition to that, a statistical analysis was also carried out to understand the effect of different climatic factors on the performance of solar stills.
Double moves by each player in chess openings make the game fairer
Authors: Brams Steven , Ismail Mehmet
Published: March 2024

Unlike tic-tac-toe or checkers, in which optimal play leads to a draw, it is not known whether optimal play in chess ends in a win for White, a win for Black, or a draw. But after White moves first in chess, if Black has a double move followed by a double move of White and then alternating play, play is more balanced because White does not always tie or lead in moves. Symbolically, Balanced Alternation gives the following move sequence: After White’s (W) initial move, first Black (B) and then White each have two moves in a row (BBWW), followed by the alternating sequence, beginning with W, which altogether can be written as WB\slashBW\slash WB\slash WB\slash WB…(the slashes separate alternating pairs of moves). Except for reversal of the 3rd and 4th moves from WB to BW (underscored), this is the standard chess sequence. Because Balanced Alternation lies between the standard sequence, which favors White, and a comparable sequence that favors Black, it is highly likely to produce a draw with optimal play, rendering chess fairer.
The human subthalamic nucleus transiently inhibits active attentional processes
Authors: Soh Cheol , Hervault Mario , Chalkley Nathan H , Moore Cathleen M , Rohl Andrea , Zhang Qiang , Uc Ergun Y , Greenlee Jeremy D W , Wessel Jan R
Published: March 2024

The subthalamic nucleus (STN) of the basal ganglia is key to the inhibitory control of movement. Consequently, it is a primary target for the neurosurgical treatment of movement disorders like Parkinson’s disease, where modulating the STN via deep brain stimulation (DBS) can release excess inhibition of thalamocortical motor circuits. However, the STN is also anatomically connected to other thalamocortical circuits, including those underlying cognitive processes like attention. Notably, STN-DBS can also affect these processes. This suggests that the STN may also contribute to the inhibition of non-motor activity and that STN-DBS may cause changes to this inhibition. Here we tested this hypothesis in humans.

We used a novel, wireless outpatient method to record intracranial local field potentials (LFP) from STN DBS implants during a visual attention task (Experiment 1, n = 12). These outpatient measurements allowed the simultaneous recording of high-density EEG, which we used to derive the steady state visual evoked potential (SSVEP), a well established neural index of visual attentional engagement. By relating STN activity to this neural marker of attention (instead of overt behaviour), we avoided possible confounds resulting from STN’s motor role. We aimed to test whether the STN contributes to the momentary inhibition of the SSVEP caused by unexpected, distracting sounds. Furthermore, we causally tested this association in a second experiment, where we modulated STN via DBS across two sessions of the task, spaced at least 1 week apart (n = 21, no sample overlap with Experiment 1).

The LFP recordings in Experiment 1 showed that reductions of the SSVEP after distracting sounds were preceded by sound-related γ-frequency (>60 Hz) activity in the STN. Trial-to-trial modelling further showed that this STN activity statistically mediated the sounds’ suppressive effect on the SSVEP. In Experiment 2, modulating STN activity via DBS significantly reduced these sound-related SSVEP reductions. This provides causal evidence for the role of the STN in the surprise-related inhibition of attention.

These findings suggest that the human STN contributes to the inhibition of attention, a non-motor process. This supports a domain-general view of the inhibitory role of the STN. Furthermore, these findings also suggest a potential mechanism underlying some of the known cognitive side effects of STN-DBS treatment, especially on attentional processes. Finally, our newly established outpatient LFP recording technique facilitates the testing of the role of subcortical nuclei in complex cognitive tasks, alongside recordings from the rest of the brain, and in much shorter time than peri-surgical recordings.
Cholinergic changes in Lewy body disease: implications for presentation, progression and subtypes
Authors: Okkels Niels , Grothe Michel J , Taylor John-Paul , Hasselbalch Steen Gregers , Fedorova Tatyana D , Knudsen Karoline , van der Zee Sygrid , van Laar Teus , Bohnen Nicolaas I , Borghammer Per , Horsager Jacob
Published: March 2024

Cholinergic degeneration is significant in Lewy body disease, including Parkinson’s disease, dementia with Lewy bodies, and isolated REM sleep behaviour disorder. Extensive research has demonstrated cholinergic alterations in the CNS of these disorders. More recently, studies have revealed cholinergic denervation in organs that receive parasympathetic denervation. This enables a comprehensive review of cholinergic changes in Lewy body disease, encompassing both central and peripheral regions, various disease stages and diagnostic categories.

Across studies, brain regions affected in Lewy body dementia show equal or greater levels of cholinergic impairment compared to the brain regions affected in Lewy body disease without dementia. This observation suggests a continuum of cholinergic alterations between these disorders. Patients without dementia exhibit relative sparing of limbic regions, whereas occipital and superior temporal regions appear to be affected to a similar extent in patients with and without dementia. This implies that posterior cholinergic cell groups in the basal forebrain are affected in the early stages of Lewy body disorders, while more anterior regions are typically affected later in the disease progression. The topographical changes observed in patients affected by comorbid Alzheimer pathology may reflect a combination of changes seen in pure forms of Lewy body disease and those seen in Alzheimer’s disease. This suggests that Alzheimer co-pathology is important to understand cholinergic degeneration in Lewy body disease. Thalamic cholinergic innervation is more affected in Lewy body patients with dementia compared to those without dementia, and this may contribute to the distinct clinical presentations observed in these groups. In patients with Alzheimer’s disease, the thalamus is variably affected, suggesting a different sequential involvement of cholinergic cell groups in Alzheimer’s disease compared to Lewy body disease. Patients with isolated REM sleep behaviour disorder demonstrate cholinergic denervation in abdominal organs that receive parasympathetic innervation from the dorsal motor nucleus of the vagus, similar to patients who experienced this sleep disorder in their prodrome. This implies that REM sleep behaviour disorder is important for understanding peripheral cholinergic changes in both prodromal and manifest phases of Lewy body disease.

In conclusion, cholinergic changes in Lewy body disease carry implications for understanding phenotypes and the influence of Alzheimer co-pathology, delineating subtypes and pathological spreading routes, and for developing tailored treatments targeting the cholinergic system.
Making amends: emotions and the western response to Russia's invasion of Ukraine
Authors: Floyd Rita , Webber Mark
Published: March 2024

The western response to Russia's full-scale invasion of Ukraine in February 2022 was unprecedented. The states of the European Union, the G7 and NATO have targeted Russia with sanctions and diplomatic isolation, and furnished Ukraine with military assistance sufficient to ensure the Zelensky regime's survival. These efforts have proven insufficient to dislodge Russia from its occupation of Ukrainian territory. Nonetheless, when launched in the aftermath of the invasion, they were seen (and often justified as) as bold, innovative, and steadfast—a necessary response to a grievous act. What explains this response? In this article we argue that the answer lies in the emotions of guilt and shame for past actions and mistakes in the West's dealings with Russia and Ukraine. Informed by a qualitative discourse analysis of key speeches, statements and interviews with leading western policy-makers (past and present), we regard these two emotions—expressed as apologies and the acknowledgment of mistakes—as important drivers of policy. This article contributes to the bourgeoning literature on emotions in world politics. In addition to offering a coherent explanation of the West's unprecedented response our argument has policy implications. While the admission of wrongdoing is laudable, it can lead to actors overcompensating, resulting in further mistakes and policy failures. Fast-tracking Ukraine into the European Union would be one such error.
Understanding Bangladesh's security governance through peacekeeping assemblage: does contribution matter?
Authors: Biswas Niloy Ranjan
Published: March 2024

How do international peacekeeping experiences inform the security governance of contributing states from the global South? This article advances theoretical and policy arguments that international peacekeeping exposure contributes to forming multitudes of effects on domestic security affairs and shaping the contributing countries' security governance. The analysis problematizes the transformation of norms, policies, practices and institutional approaches in shaping the national security outlook of the contributing nations. Considering peacekeeping as a discursive ‘glo-cal’ affair and Bangladesh as a critical case, this study underscores how Bangladesh's contributions to United Nations Peace Support Operations (UNPSOs) inform its security governance. The article adopts a qualitative–interpretive approach to examine the assembling effects of Bangladesh's participation in such endeavours. It highlights the transformation in security institutions, new capacities in knowledge and income-generating sectors, new peacekeeping norms, and partnerships in security cooperation as the cornerstones in the national security outlook. Extending the purview of the existing literature on contributors' roles and impact, this article has offered assemblage as a dynamic conceptual lens to understand new domestic significance for the armed forces as global peace providers. Challenges related to the struggle for democracy, political stability and good governance persist in Bangladesh; nevertheless, the peacekeeping assemblage explains how the country has considered accelerating its global peace endeavours.
Evaluating team-based learning in a foundation training pathway for trainee pharmacists
Authors: Medlinskiene Kristina , Hill Suzanne , Tweddell Simon , Quinn Gemma
Published: March 2024

Background

A new programme incorporating online study days delivered using team-based learning (TBL) for hospital-based trainee pharmacists (TPs) in the North of England was created. To our knowledge, TBL has not previously been used in educational programmes for TPs designed to supplement their workplace learning. The project aimed to investigate the experiences of TPs learning using online TBL by exploring their perceptions on their engagement, learning, and satisfaction with TBL.

Method

Data were collected using online anonymous surveys at the end of four online TBL study days. A bespoke survey consisted of 5-point or 4-point Likert scale and two free text questions. TBL Student Assessment Instrument (SAI), a validated survey, was used to assess TPs’ acceptance of TBL. Survey data was summarized descriptively, and free text comments analysed using thematic analysis.

Results

TPs developed accountability to their team, remained engaged with TBL delivery online and stated a preference for and satisfaction with this method. TPs valued opportunities to apply their knowledge in challenging scenarios and learn from discussions with their peers, the larger group, and facilitators. TBL was also perceived to be an engaging approach to learning and helped to maintain their interest with the teaching material. However, TPs struggled to engage with pre-work outside of the class due to competing work priorities.

Discussion

This study shows that online TBL was well accepted by TPs and can be successfully used to deliver education to large cohorts of learners. The model developed shows potential for scalability to larger numbers of learners.
Efficient least-squares reverse time migration in TTI media using a finite-difference solvable pure qP-wave equation
Authors: Mao Qiang , Huang Jianping , Mu Xinru , Zhang Zixiao , Zhang Yujian
Published: March 2024

The anisotropic characteristics of underground media play a crucial role in seismic wave propagation and should be accounted for during seismic imaging. The least-squares reverse time migration (LSRTM) method achieves ideal imaging results by suppressing migration artifacts and balancing amplitude. Therefore, pure quasi-P (P-qP) wave equations in tilted transversely isotropic (TTI) media have been widely used to implement LSRTM, owing to their ability to produce stable and noise-free wavefields. However, solving the anisotropic P-qP-wave equations typically necessitates the use of spectral-based methods, making them computationally inefficient, especially in 3D applications. In this study, we first develop a P-qP-wave equation in TTI media that can be efficiently computed through the finite-difference (FD) approach. Numerical tests show that, in comparison to the previous TTI P-qP-wave equation, the newly derived FD solvable TTI P-qP-wave equation yields reasonably accurate and highly efficient wavefield simulations. Then, building on our newly derived wave equation, we derive its adjoint migration and demigration operator to implement TTI LSRTM. Two synthetic examples suggest that the newly presented P-qP-wave TTI LSRTM approach effectively correct for the anisotropy effects, providing high-quality imaging results. Additionally, our approach has superior computational efficiency over the conventional P-qP-wave TTI LSRTM technique based on a hybrid FD pseudo-spectral (HFDPS) solver.
Doubly robust calibration of prediction sets under covariate shift
Authors: Yang Yachong , Kuchibhotla Arun Kumar , Tchetgen Tchetgen Eric
Published: March 2024

Conformal prediction has received tremendous attention in recent years and has offered new solutions to problems in missing data and causal inference; yet these advances have not leveraged modern semi-parametric efficiency theory for more efficient uncertainty quantification. We consider the problem of obtaining well-calibrated prediction regions that can data adaptively account for a shift in the distribution of covariates between training and test data. Under a covariate shift assumption analogous to the standard missing at random assumption, we propose a general framework based on efficient influence functions to construct well-calibrated prediction regions for the unobserved outcome in the test sample without compromising coverage.
Simultaneous false discovery proportion bounds via knockoffs and closed testing
Authors: Li Jinzhou , Maathuis Marloes H , Goeman Jelle J
Published: March 2024

We propose new methods to obtain simultaneous false discovery proportion bounds for knockoff-based approaches. We first investigate an approach based on Janson and Su’s k-familywise error rate control method and interpolation. We then generalize it by considering a collection of k values, and show that the bound of Katsevich and Ramdas is a special case of this method and can be uniformly improved. Next, we further generalize the method by using closed testing with a multi-weighted-sum local test statistic. This allows us to obtain a further uniform improvement and other generalizations over previous methods. We also develop an efficient shortcut for its implementation. We compare the performance of our proposed methods in simulations and apply them to a data set from the UK Biobank.
bHLH121 and clade IVc bHLH transcription factors synergistically function to regulate iron homeostasis in Arabidopsis thaliana
Authors: Gao Fei , Li Meijie , Dubos Christian
Published: March 2024

Iron is an essential micronutrient for plant growth and development. In Arabidopsis thaliana, an intricate regulatory network involving several basic helix–loop–helix (bHLH) transcription factors controls the homeostasis of iron. Among these transcription factors, bHLH121 plays a crucial role. bHLH121 interacts in vivo with clade IVc bHLH transcription factors and activates the expression of FIT and clade Ib bHLH transcription factors to stimulate the uptake of iron. How bHLH121 and clade IVc bHLH transcription factors function collectively and efficiently to maintain iron homeostasis is still unclear. Herein, we found that double loss-of-function mutants involving bhlh121 and one of the clade IVc bHLH transcription factors displayed more severe iron deficiency-associated growth defects than each of the single mutants. We also found that among the four clade IVc bHLH transcription factors, only bHLH34 and bHLH105 could partially complement the iron-associated growth defects of bhlh121 when overexpressed. These data, together with protein localization analysis, support that bHLH121 and clade IVc bHLH transcription factors act synergistically to regulate iron homeostasis and that different bHLH121/clade IVc and clade IVc/clade IVc protein complexes are involved in this process.
Ascorbate peroxidase in fruits and modulation of its activity by reactive species
Authors: Corpas Francisco J , González-Gordo Salvador , Palma José M
Published: March 2024

Ascorbate peroxidase (APX) is one of the enzymes of the ascorbate–glutathione cycle and is the key enzyme that breaks down H2O2 with the aid of ascorbate as an electron source. APX is present in all photosynthetic eukaryotes from algae to higher plants and, at the cellular level, it is localized in all subcellular compartments where H2O2 is generated, including the apoplast, cytosol, plastids, mitochondria, and peroxisomes, either in soluble form or attached to the organelle membranes. APX activity can be modulated by various post-translational modifications including tyrosine nitration, S-nitrosation, persulfidation, and S-sulfenylation. This allows the connection of H2O2 metabolism with other relevant signaling molecules such as NO and H2S, thus building a complex coordination system. In both climacteric and non-climacteric fruits, APX plays a key role during the ripening process and during post-harvest, since it participates in the regulation of both H2O2 and ascorbate levels affecting fruit quality. Currently, the exogenous application of molecules such as NO, H2S, H2O2, and, more recently, melatonin is seen as a new alternative to maintain and extend the shelf life and quality of fruits because they can modulate APX activity as well as other antioxidant systems. Therefore, these molecules are being considered as new biotechnological tools to improve crop quality in the horticultural industry.
Introducing the Condor Array Telescope – III. The expansion and age of the shell of the dwarf nova Z Camelopardalis, and detection of a second, larger shell
Authors: Shara Michael M , Lanzetta Kenneth M , Garland James T , Gromoll Stefan , Valls-Gabaud David , Walter Frederick M , Webb John K , Zurek David R , Brosch Noah , Rich R Michael
Published: March 2024

The existence of a vast nova shell surrounding the prototypical dwarf nova Z Camelopardalis (Z Cam) proves that some old novae undergo metamorphosis to appear as dwarf novae thousands of years after a nova eruption. The expansion rates of ancient nova shells offer a way to constrain both the time between nova eruptions and the time for post-nova mass transfer rates to decrease significantly, simultaneously testing nova thermonuclear runaway models and hibernation theory. Previous limits on the expansion rate of part of the Z Cam shell constrain the inter-eruption time between Z Cam nova events to be >1300 yr. Deeper narrow-band imaging of the ejecta of Z Cam with the Condor Array Telescope now reveals very low surface brightness areas of the remainder of the shell. A second, even fainter shell is also detected, concentric with and nearly three times the size of the ‘inner’ shell. This is the first observational support of the prediction that concentric shells must surround the frequently erupting novae of relatively massive white dwarfs. The Condor images extend our Z Cam imaging baseline to 15 yr, yielding the inner shell’s expansion rate as v = 83 ± 37 km s−1 at 23 deg south of west, in excellent agreement with our 2012 prediction. This velocity corresponds to an approximate age of $t = 2672^{-817}_{+2102}$ yr. While consistent with the suggestion that the most recent nova eruption of Z Cam was the transient recorded by Chinese imperial astrologers in the year 77 bce, the age uncertainty is still too large to support or disprove a connection with Z Cam.
Introducing the Condor array telescope II – deep imaging observations of the edge-on spiral galaxy NGC 5907 and the NGC 5866 Group: yet another view of the iconic stellar stream
Authors: Lanzetta Kenneth M , Gromoll Stefan , Shara Michael M , Berg Stephen , Garland James , Mancini Evan , Valls-Gabaud David , Walter Frederick M , Webb John K
Published: March 2024

We used the Condor array telescope to obtain deep imaging observations through the luminance filter of the entirety of the NGC 5866 Group, including a very extended region surrounding the galaxy NGC 5907 and its stellar stream. We find that the stellar stream consists of a single curved structure that stretches 220 kpc from a brighter eastern stream to a fainter western stream that bends to the north and then curls back toward the galaxy. This result runs contrary to a previous claim of a second loop of the stellar stream but is consistent with another previous description of the overall morphology of the stream. We further find that: (1) an extension of the western stream appears to bifurcate near its apex, (2) there is an apparent gap of ≈6 kpc in the western stream due east of the galaxy, (3) contrary to a previous claim, there is no evidence of the remnant of a progenitor galaxy within the eastern stream, although (4) there are many other possible progenitor galaxies, (5) there is another structure that, if it is at the distance of the galaxy, stretches 240 kpc and contains two very large, very low-surface-brightness ‘patches’ of emission, one of which was noted previously and another of which was not. We note the number and variety of stellar streams in the vicinity of NGC 5907 and the apparent gap in the western stream, which may be indicative of a dark sub-halo or satellite in the vicinity of the galaxy.
Systematic review for the treatment of older rheumatoid arthritis patients informing the 2024 update of the Japan College of Rheumatology clinical practice guidelines for the management of rheumatoid arthritis
Authors: Sugihara Takahiko , Kawahito Yutaka , Kaneko Yuko , Tanaka Eiichi , Yanai Ryo , Yajima Nobuyuki , Kojima Masayo , Harigai Masayoshi
Published: March 2024

Objectives

To update an evidence base informing the 2024 Japan College of Rheumatology clinical practice guidelines for the management of rheumatoid arthritis (RA) in older adults.

Methods

Four clinical questions (CQs) regarding efficacy and safety of drug treatment were evaluated, with CQ1 addressing methotrexate (MTX), CQ2 biological disease-modifying antirheumatic drugs, CQ3 Janus kinase (JAK) inhibitors, and CQ4 glucocorticoids (GCs). Quality of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation system.

Results

Observational studies confirmed a pivotal role of methotrexate in the treatment of older RA patients. The meta-analysis showed that tumour necrosis factor inhibitors and JAK inhibitors were unequivocally effective in older RA patients. No data indicated that biological disease-modifying antirheumatic drugs were unsafe for older patients. No safety data for JAK inhibitor use in older patients were available. One randomized controlled trial demonstrated that long-term treatment with low-dose GCs increased risks of GC-associated adverse events. The certainty of overall evidence was very low for all CQs.

Conclusions

This systematic review provides the necessary evidence for developing 2024 Japan College of Rheumatology clinical practice guidelines for managing older patients with RA. Continued updates on the evidence of JAK inhibitors and GC are desired.