bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of radiation safety culture among radiological technologists in medical imaging departments in Saudi Arabia
Authors: Shubayr N. , Muawwadhah Md. , Shami M. , Jassas H. , Tawhari R. , Oraybi O. , Madkhali A. , Aldosari A. , Alashban Y.
Published: March 2024

This study aimed to evaluate the perception of radiation safety culture among medical radiological technologists (MRTs) in the Kingdom of Saudi Arabia. The study was performed from June 2022 to February 2023 and involved MRTs from various hospitals and medical centres in Saudi Arabia. A cross-sectional study was conducted using a self-administered and previously validated radiation safety culture survey instrument in medical imaging departments. The survey comprises 11 determinants of radiation safety culture, including personal accountability, teamwork in imaging, teamwork across imaging stakeholders, questioning attitude, feedback loops, organisational learning, leadership actions, non-punitive response, error reporting, radiation policy and overall perception of radiation safety. A total of 496 MRTs participated in this study. Results showed that most of the MRTs were male (75.0%), between 25 and 44 yr old (71.0%), with a bachelor’s degree (53.2%) and had less than 5 yr of experience (41.1%). The highest mean scores were for personal accountability (4.43 ± 0.62) and teamwork in imaging (4.22 ± 0.91), while the lowest mean score was for non-punitive response (2.94 ± 1.01). The majority of the MRTs reported good perception for the personal accountability (71.8%), teamwork in imaging (56.5%) and organisational learning (46%) scales; moderate perception for the teamwork across imaging stakeholders (53.2%), questioning attitude (71%), feedback loops (47.6%), leadership actions (74.2%), error reporting (53.2%), radiation policy (54.8%) and overall perception of radiation safety (62.1%) scales; and poor perception for the non-punitive response scale (45.2%). Individual and organisational interference are warranted to adhere to a strong radiation safety culture with continuing education. Moreover, repeated measures are necessary to assess for categorical improvement associated with the relevant determinants that are also important to support a positive radiation safety culture.
Impact of implementing national diagnostic reference levels on radiation dose optimization in adult chest CT scans: a comparative analysis
Authors: Sindi R. , Al-Shamrani B. , Bana A. , Al-Qurashi F. , Al-Qarhi M. , Al-Shehri B. , Al-Otaibi R. , Aldawood S. , Shubayr N.
Published: March 2024

The management and optimization of radiation dose in computed tomography (CT) examinations is of paramount importance, especially when the safety of patients is concerned. This study evaluated the effect of implementing national diagnostic reference levels (NDRLs) for radiation dose optimization in 1991 adult chest CT scans at a major Saudi hospital. Data was analyzed before and after NDRL implementation, with 21.5% of scans using contrast and 78.5% without. Before implementation, 11.1% used contrast and 36.7% did not; after implementation, 10.4% used contrast and 41.7% did not. The majority (83.5%) of scans passed NDRL criteria [CTDIvol and DLP are set at 12 (mGy) and 430 (mGy · cm)], with higher pass rates for contrast (91.8%) versus non-contrast (81.5%) scans. Effective dose (ED) was compared before and after NDRL implementation. For non-contrast scans, ED declined 2.43% from 12.37 ± 5.25 mSv to 12.07 ± 4.99 mSv after implementation (non-significant, p > 0.05). For contrast scans, ED declined more substantially, 6.77% from 9.6 ± 4.61 mSv to 8.95 ± 4.44 mSv (non-significant, p > 0.05). The findings highlight higher NDRL compliance in procedures with contrast and show areas for dose optimization improvement in procedures without contrast. Results suggest NDRLs provide guidance for optimizing radiation dose, but other factors like patient characteristics, protocol settings, and quality assurance programs should also be considered to ensure doses are as low as reasonably achievable (ALARA) without compromising diagnostic quality. Regular monitoring and review of CT protocols is recommended to avoid unintended consequences of dose reduction. Continued optimization is encouraged to reduce dose while ensuring quality.
Modeling and simulation of complex emergency dispatch based on BIPSO
Authors: Sun Zimei , Huang Chengning
Published: March 2024

In emergency task scheduling, this study proposes a complex model for emergency scheduling. It is based on the particle swarm algorithm and improves upon the traditional version. Additionally, the study recommends the use of the binary particle swarm optimization algorithm (PSO). The study proposes applying the multi-objective task scheduling-particle swarm optimization algorithm (MOTS-PSO) to the complex emergency scheduling model by combining it with the multi-objective function. Compared to other algorithms, the proposed improved algorithm exhibited the lowest average number of iterations, which consistently fell within the range of 130, and achieved a 100% success rate for optimization searches on the majority of functions. When compared with other models, the proposed research model demonstrated superior performance, exhibiting the lowest total scheduling cost, total execution time, and data transfer time of 280 and 900, respectively, for the task quantity of 5000. Furthermore, the proposed model exhibited the lowest maximum execution cost for a single node, which remained within the range of 0.45S. The outcomes of the experiments demonstrate that the proposed research model adequately satisfies the requirements for complex scheduling and its simulability has been confirmed.
The Frequency of Neuropathic Pain and Associated Factors in Patients
with Rheumatoid Arthritis
Authors: Büyük Ferda , Borman Pınar , Bakırcı Esra Şahingöz , Karakılıç Gülseren Demir
Published: March 2024

Objective The aim of this study was to evaluate the presence and incidence
of neuropathic pain (NP) in patients with rheumatoid arthritis (RA) and to
determine the relationship between neuropathic pain scores, quality of life and
functional status.

Methods 119 patients with RA and 45 control subjects with acute
non-inflammatory pain were recruited for the study. Disease activity with DAS28
(Disease Activity Score-28), pain visual analog scale, functional status and
quality of life were recorded. Quality of life was evaluated with the Rheumatoid
Arthritis Quality of Life Scale (RAQoL), and functional status was assessed with
the Health Assessment Questionnaire (HAQ). The presence of NP was evaluated with
the LANSS (Leeds Assessment of Neuropathic Symptoms and Signs), Douleur
Neuropathique 4 (DN4) and painDETECT questionnaires (PDQ).

Results The prevalence of NP according to LANSS, DN4 and PDQ was 63.9%,
58.8% and 51.3% in the RA group and 6.7%, 4.4% and 4.4% in the control group,
respectively. NP scores were significantly higher in the RA group (p<0.001).
LANSS, DN4 and PDQ scores correlated with VAS, HAQ and RAQoL scores.

Conclusion The NP evaluated with different pain questionnaires is not rare
in patients with RA and is related to functional status and quality of life.
Anatomical and Technical Considerations in Fascicular Nerve Transfers for Foot Drop
Authors: Seruya Mitchel
Published: March 2024

Background Foot drop is the common endpoint for a diverse set of nerve injuries, affecting over 128,000 in the United States each year. The level of injury, finite pace of regeneration, and/ exponential decay in the percentage of motor end-plates reinnervated over time may explain the limited success with natural recovery. Past nerve techniques have also been met with limited success.

Methods This narrative review explores why past nerve techniques have failed to correct foot drop.

Results Previously described nerve transfer techniques suffer from incompletely balancing the foot and ankle, poor donor-target nerve synergy, and/or not effectively bypassing the wide and oftentimes underappreciated zone of injury. For maximal stability, one should look to balance the foot in both dorsiflexion and eversion. Detailed descriptions and illustrations of the branching anatomy for the peroneal and tibial nerves are provided, with specific application to nerve transfer reconstruction.

Conclusion Based on an understanding of why past nerve techniques have failed to correct foot drop, a set of surgical principles can be codified to optimize functional outcomes. A surgical technique should be versatile enough to address foot drop from any of the three common pathways of injury (lumbar spine, sciatic nerve, and common peroneal nerve). With increasing familiarity using this once poorly understood anatomical region, limitations with past nerve transfer techniques may be overcome.
(n+3)-Cyclization for the Formation of Benzo[7]annulene Derivatives via a [1,4]-Hydride Shift: A Novel Cyclization Mode Involving an Internal Redox Reaction
Authors: Mori Keiji , Nagaki Jun , Kawasaki-Takasuka Tomoko
Published: March 2024

We report a unique synthetic route to benzo[7]annulene derivatives. When benzylidene malonates having a 1-(N,N-dialkylamino)alkyl group at the ortho-position are treated with a stoichiometric amount of M(OTf)3 (M = Sc, Yb, Gd), three transformations ([1,4]-hydride shift/isomerization into an enamine/intramolecular Stork enamine acylation) proceed sequentially to afford various benzo[7]annulene derivatives in moderate chemical yields. To our knowledge, the present reaction is the first example of an internal redox reaction involving a [1,n]-hydride shift/(n+3)-cyclization process.
Regiocontrolled Ruthenium-Catalyzed Isomerization of Propargyl Alcohols
Authors: Haak Edgar , Skowaisa Steffen
Published: March 2024

A diaminocyclopentadienone ruthenium complex allows control of regioselectivity in the ruthenium-catalyzed isomerization of propargyl alcohols through the choice of additive. Thereby, both products of the Meyer–Schuster rearrangement and redox isomerization products are selectively accessible. In the presence of hydroxylamine-O-sulfonic acid, unsaturated nitriles are formed instead. The ruthenium catalyst is readily available and stable to moisture, air, and acidic conditions.
A Photochemical Strategy for the Synthesis of Caprolactams via Dearomative Ring Expansion of Nitroarenes
Authors: Ruffoni Alessandro , Leonori Daniele , Sánchez-Bento Raquel , Bui Linda , Duong Vincent K.
Published: March 2024

This paper outlines a novel strategy for the preparation of seven-membered-ring lactams from simple nitroarenes. The approach is based on a photochemical dearomative ring expansion starting with the conversion of the nitro group into a singlet nitrene. This process is mediated by blue light, occurs at room temperature and overall enables the insertion of the nitro N-atom into the benzenoid framework. This step transforms the aromatic starting material into a seven-membered ring azepine that, following hydrogenation and hydrolysis, is converted into the desired caprolactams in just three steps.
Building Equitable Neuroscience Research Collaborations in Resource-limited Settings
Authors: Asukile Melody T. , Zunt Joseph R. , Thakur Kiran T.
Published: March 2024

The burden of noncommunicable neurological disorders, such as stroke, dementia, and headache disorders, are on the rise in low- to middle-income countries (LMICs), while neuroinfectious diseases remain a major concern. The development of neuroscience research aimed at defining the burden of neurological diseases across the lifespan, as well as optimizing diagnosis and treatment strategies, is fundamental to improving neurological health in resource-limited settings. One of the key factors to advancing neuroscience research in LMICs is the establishment of effective collaborations based on responsible and trustworthy partnerships between local scientists in LMICs and international collaborators. LMIC researchers face many logistical, institutional, and individual level challenges as they embark on their neuroscience research journey. Despite these challenges, there are opportunities for improving LMIC investigator-led research that should focus on human and institutional infrastructure development. With regard to human capacity building, potential areas for offering support include enhancing research methodology training, offering instruction in manuscript and grant-writing, institutionalizing mentorship programs, and providing opportunities to conduct funded, mentored research to disseminate in high-impact journals. The foundational elements required for implementing and optimizing neuroscience research within an institution include an institutional review board, mentorship programs, data management, research administration, and laboratory facilities. This institutional capacity varies significantly across and within countries, and many rely on collaborations with better-resourced institutions to initiate research. Successful equitable collaborations ensure the engagement of all local and international stakeholders, as well as implementation of a self-sustaining long-term program. Building research capacity in LMICs is an essential endeavor that requires ongoing commitment to training independent scientists. As research capacity increases, LMIC institutions and governments should consider developing competitive research grant programs to support innovative studies led by local researchers, foster regional collaborations, and hence create a sustainable and independent neuroscience research environment.
Design and Implementation of a Didactic Curriculum in a Large Neonatal–Perinatal Medicine Fellowship Program: A Single-Center Experience
Authors: Mukthapuram Shanmukha , Johnson Beth Ann , Slagle Cara , Erickson John , Kamath-Rayne Beena D. , Brady Jennifer M.
Published: March 2024

Objective Although the Accreditation Council for Graduate Medical Education and American Board of Pediatrics (ABP) provide regulations and guidance on fellowship didactic education, each program establishes their own didactic schedules to address these learning needs. Wide variation exists in content, educators, amount of protected educational time, and the format for didactic lectures. This inconsistency can contribute to fellow dissatisfaction, a perceived poor learning experience, and poor attendance. Our objective was to create a Neonatal–Perinatal Medicine (NPM) fellow curriculum based on adult learning theory utilizing fellow input to improve the perceived fellow experience.

Study Design A needs assessment of current NPM fellows at Cincinnati Children's Hospital was conducted to guide the development of a new curriculum. Fellow perception of educational experience and board preparedness before and after introduction of the new curriculum was collected. Study period was from October 2018 to July 2021.

Results One hundred percent of the fellows responded to the needs assessment survey. A response rate of 100 and 87.5% were noted on mid-curriculum survey and postcurriculum survey, respectively. Key themes identified and incorporated into the curriculum included schedule structure, content, and delivery mode. A new didactic curriculum implementing a consistent schedule of shorter lectures grouped by organ system targeting ABP core content was created. After curriculum implementation, fellows had higher self-perception of board preparedness, and overall improved satisfaction.

Conclusion Our positive experience in implementing this curriculum provides a framework for individual programs to implement similar curricula, and could be utilized to aid in development of national NPM curricula.

Key Points
Comparison of National Factor-Based Models for Preeclampsia Screening
Authors: Ghesquière Louise , Bujold Emmanuel , Dubé Eric , Chaillet Nils
Published: March 2024

Objective This study aimed to compare the predictive values of the American College of Obstetricians and Gynecologists (ACOG), the National Institute for Health and Care Excellence (NICE), and the Society of Obstetricians and Gynecologists of Canada (SOGC) factor-based models for preeclampsia (PE) screening.

Study Design We conducted a secondary analysis of maternal and birth data from 32 hospitals. For each delivery, we calculated the risk of PE according to the ACOG, the NICE, and the SOGC models. Our primary outcomes were PE and preterm PE (PE combined with preterm birth) using the ACOG criteria. We calculated the detection rate (DR or sensitivity), the false positive rate (FPR or 1 − specificity), the positive (PPV) and negative (NPV) predictive values of each model for PE and for preterm PE using receiver operator characteristic (ROC) curves.

Results We used 130,939 deliveries including 4,635 (3.5%) cases of PE and 823 (0.6%) cases of preterm PE. The ACOG model had a DR of 43.6% for PE and 50.3% for preterm PE with FPR of 15.6%; the NICE model had a DR of 36.2% for PE and 41.3% for preterm PE with FPR of 12.8%; and the SOGC model had a DR of 49.1% for PE and 51.6% for preterm PE with FPR of 22.2%. The PPV for PE of the ACOG (9.3%) and NICE (9.4%) models were both superior than the SOGC model (7.6%; p < 0.001), with a similar trend for the PPV for preterm PE (1.9 vs. 1.9 vs. 1.4%, respectively; p < 0.01). The area under the ROC curves suggested that the ACOG model is superior to the NICE for the prediction of PE and preterm PE and superior to the SOGC models for the prediction of preterm PE (all with p < 0.001).

Conclusion The current ACOG factor-based model for the prediction of PE and preterm PE, without considering race, is superior to the NICE and SOGC models.

Key Points
Modified Steinberg–Guinan elasticity model to describe softening–hardening dual anomaly in vanadium
Authors: Wang Hao , Gan Yuan-Chao , Chen Xiang-Rong , Wang Yi-Xian , Geng Hua Y.
Published: March 2024

Constitutive models are essential for describing the mechanical behavior of materials under high temperatures and pressures, among which the Steinberg–Guinan (SG) model is widely adopted. Recent work has discovered a peculiar dual anomaly of compression-induced softening and heating-induced hardening in the elasticity of compressed vanadium [Phys. Rev. B 104, 134102 (2021)], which is beyond the capability of the SG model to describe. In this work, a modified SG elasticity constitutive model is proposed to embody such an anomalous behavior. Elemental vanadium is considered as an example to demonstrate the effectiveness of this improved model in describing the dual anomalies of elasticity. This new SG elasticity model can also be applied to other materials that present an irregular variation in the mechanical elasticity and are important to faithfully model and simulate the mechanical response of materials under extreme conditions.
Fabrication of single-crystalline YFeO3 films with large antiferromagnetic domains
Authors: Wang Cong , Lippmaa Mikk , Nakatsuji Satoru
Published: March 2024

The antiferromagnetic orthoferrite YFeO3 possesses fascinating magnetic properties for spintronics, such as terahertz spin dynamics, ultrafast domain wall motion, and long magnon decay length. YFeO3 belongs to a special family of antiferromagnets that show an unusually strong non-trivial Kerr response due to its weak ferromagnetism. The highly stable antiferromagnetic domains without any spontaneous spin rotation transitions below the 645 K Néel temperature may be useful for nanoscale device applications. We report the successful fabrication of high-quality twinning-free (110)-oriented YFeO3 films by pulsed laser deposition. Detailed structural and magnetic characterization revealed that the crystal structure and magnetic properties of the YFeO3 films are comparable to bulk single crystals. We show that the spin rotation under high magnetic fields follows the two-sublattice approximation model. The film surface is atomically flat with step-terrace surface morphology. A longitudinal magneto-optic Kerr (MOKE) rotation of 10 mdeg was observed at room temperature, which is consistent with earlier reports on bulk single crystals. The in-plane anisotropy of the Kerr response corresponds to the obtained magnetic anisotropy from the SQUID measurement. The large MOKE signal enables the imaging of antiferromagnetic domains and their reversal. The domain size was found to be larger than 100 μm. These high-quality YFeO3 thin films facilitate the fabrication of antiferromagnetic spintronic devices and provide a convenient platform for studying various spin-related phenomena in thin films and at interfaces.
Relativistic effect influencing the diverse bonding character of the interfacial Ag staple motifs in thiolate-protected nanoclusters
Authors: Wang Endong , Gao Yi
Published: March 2024

Thiolate-protected noble-metal nanoclusters have recently attracted extensive attention due to their appealing properties in optics, catalysis, etc. Within the same group element, experiments indicate that Ag staples exhibit di-, tri-, or even tetra-coordination, in contrast to the di-coordination observed in Au staples, rendering the structures of Ag nanoclusters more intricate. However, the underlying chemical insight of the bonding feature of multiple-coordinated Ag staples remains unclear. In this study, we employed density functional theory coupled with all-electron scalar relativistic calculations to elucidate the critical role of relativistic effect in determining the conformational complexity of Ag staples. Unlike Au, the relatively weaker relativistic effect induces fewer contributions of d orbitals in bonding for the Ag atom, showing an extreme sensitivity to the structural architecture in liganded clusters. A relatively higher d orbital percentage favors di-coordination with a shortened Ag–S bond, while a relatively lower d orbital percentage favors tri- and tetra-coordinations with an elongated Ag–S bond. The Lewis structures of the multi-coordinated Ag motifs were also unveiled. In addition, two AgNCs, including the [Ag29(SCH3)18]3− cluster with tri-coordinated Ag motifs and [Ag29(SCH3)18(PCH3)6]3− with tetra-coordinated Ag motifs, were predicted after clarifying the bonding characters of the multiple-coordinated Ag motifs. This work not only deepens the understanding of the bonding characteristics of the Ag staple motif in AgNCs and AuAg alloy clusters but also provides a new perspective to understand the relativistic effect in the thiolate-protected noble-metal nanocluster.
Cosmic strings arising in a self-dual Abelian Higgs model
Authors: Cao Lei , Chen Shouxin
Published: March 2024

In this note we construct self-dual cosmic strings from an Abelian Higgs model in two-dimension with a polynomial formation of the potential energy density. By integrating the Einstein equations, we obtain an equivalent form to the sources, which is a nonlinear elliptic equation with singularities and complicated exponential terms. We prove the existence of a solution governing strings in the broken symmetry category on the whole plane, and the multiple string solutions are valid under a sufficient condition imposed only on the total number of strings. The technique of upper–lower solutions and the method of regularization are employed to show the existence of a solution when there are at least two distant string centers. When all the string centers are identical, a fixed-point theorem is used to study the properties of the nonlinear elliptic equation. Finally, we establish the sharp asymptotic estimate for the solutions at infinity and derive the dependence of the total gravitational curvature on the string number.
Experimental two-dimensional infrared spectra of methyl thiocyanate in water and organic solvents
Authors: Shirley Joseph C. , Baiz Carlos R.
Published: March 2024

Thiocyanates, nitriles, and azides represent a versatile set of vibrational probes to measure the structure and dynamics in biological systems. The probes are minimally perturbative, the nitrile stretching mode appears in an otherwise uncongested spectral region, and the spectra report on the local environment around the probe. Nitrile frequencies and lineshapes, however, are difficult to interpret, and theoretical models that connect local environments with vibrational frequencies are often necessary. However, the development of both more accurate and intuitive models remains a challenge for the community. The present work provides an experimentally consistent collection of experimental measurements, including IR absorption and ultrafast two-dimensional infrared (2D IR) spectra, to serve as a benchmark in the development of future models. Specifically, we catalog spectra of the nitrile stretching mode of methyl thiocyanate (MeSCN) in fourteen different solvents, including non-polar, polar, and protic solvents. Absorption spectra indicate that π-interactions may be responsible for the line shape differences observed between aromatic and aliphatic alcohols. We also demonstrate that a recent Kamlet–Taft formulation describes the center frequency MeSCN. Furthermore, we report cryogenic infrared spectra that may lead to insights into the peak asymmetry in aprotic solvents. 2D IR spectra measured in protic solvents serve to connect hydrogen bonding with static inhomogeneity. We expect that these insights, along with the publicly available dataset, will be useful to continue advancing future models capable of quantitatively describing the relation between local environments, line shapes, and dynamics in nitrile probes.
Performance evaluation and enhancement of turbulent flow and convective heat transfer characteristics for turbine blade internal cooling
Authors: Zhang Ben-Xi , Wang Li-Qian , Lu Wei , Xu Jiang-Hai , Wang Yi-Bo , Yang Yan-Ru , Wang Xiao-Dong
Published: March 2024

For turbine blade internal cooling, the performance of turbulent flow and convective heat transfer in the cooling channel is numerically investigated via the computational fluid dynamics method, where the cooling channel adopts the combination of transverse rib arrangements and round-edged rib configurations or the combination of oblique rib arrangements and round-edged rib configurations. Under these two combination conditions, the simulation result shows that in the wide Reynolds number range of Re = 20 000–80 000, the heat transfer enhancement and the flow loss reduction, such as the larger normalized Nusselt number of Nu/Nu0 and smaller normalized friction factor of f/f0, are simultaneously realized by the oblique rather than transverse rib arrangement. In the oblique rib channel, the relationship between turbulent flow and convective heat transfer is for the first time revealed by the relationship between secondary vortices and turbulent kinetic energies. Based on the relation between secondary vortices and turbulent kinetic energies, the overall performance of turbulent flow and convective heat transfer for the oblique rib channel is first optimized by various normalized rib height, e/Dh, and rib spacing, p/e, and then evaluated by both overall performance factors of OPT1 and OPT2. Both OPT1 and OPT2 are larger at e/Dh = 0.062 and p/e = 15.00 in the wide range of e/Dh = 0.047–0.101 and p/e = 10.00–15.00. As a result of the comprehensive evaluation of OPT1 and OPT2, the combination of e/Dh = 0.062 and p/e = 15.00 is eventually employed by the oblique rib channel.
Control of chaos in Darcy–Bénard axisymmetric convection in a cylindrical enclosure using a uniform vertical cross-flow
Authors: Kanchana C. , Siddheshwar P. G. , Laroze D.
Published: March 2024

The linear and weakly nonlinear stability analyses of Darcy–Bénard convection of a Newtonian fluid experiencing a uniform vertical cross-flow is investigated in the paper for various aspect ratios. Making use of the Maclaurin series representation, an expression for axial eigenfunctions is obtained with the radial eigenfunction being a Bessel function of first kind. These eigenfunctions are influenced by the Peclet number, Pe, the non-dimensional number that signifies the rate of vertical cross-flow. The modified-Vadasz-Lorenz model obtained in this paper has newly defined non-dimensional parameters that capture the influence of vertical cross-flow. From the linear stability analysis, it is found that the effect of introducing vertical cross-flow is to stabilize the system. Using a weakly nonlinear stability analysis, the closed-form expression of the Hopf-Rayleigh number as a function of Pe is obtained. Furthermore, the behavior of the modified-Vadasz–Lorenz model is analyzed using the largest Lyapunov exponent and the bifurcation diagram. This gives information about the intensity of chaos and occurrence of the periodic motion. We observe that the influence of vertical cross-flow is to increase the value of the Hopf–Rayleigh number and thereby to delay the onset of chaos. Furthermore, the appearance of the first periodic point is preponed due to the vertical cross-flow. As the rate of vertical cross-flow increases, the intensity of chaos decreases, thereby indicating that the effect of introducing vertical cross-flow is to suppress chaos.
A hybrid proper orthogonal decomposition and next generation reservoir computing approach for high-dimensional chaotic prediction: Application to flow-induced vibration of tube bundles
Authors: Liu Tongwei , Zhao Xielin , Sun Pan , Zhou Jinxiong
Published: March 2024

Chaotic time series prediction is a central science problem in diverse areas, ranging from engineering, economy to nature. Classical chaotic prediction techniques are limited to short-term prediction of low- or moderate-dimensional systems. Chaotic prediction of high-dimensional engineering problems is notoriously challenging. Here, we report a hybrid approach by combining proper orthogonal decomposition (POD) with the recently developed next generation reservoir computing (NGRC) for the chaotic forecasting of high-dimensional systems. The hybrid approach integrates the synergistic features of the POD for model reduction and the high efficiency of NGRC for temporal data analysis, resulting in a new paradigm on data-driven chaotic prediction. We perform the first chaotic prediction of the nonlinear flow-induced vibration (FIV) of loosely supported tube bundles in crossflow. Reducing the FIV of a continuous beam into a 3-degree-of-freedom system using POD modes and training the three time coefficients via a NGRC network with three layers, the hybrid approach can predict time series of a weakly chaotic system with root mean square prediction error less than 1% to 19.3 Lyapunov time, while a three Lyapunov time prediction is still achieved for a highly chaotic system. A comparative study demonstrates that the POD-NGRC outperforms the other existing methods in terms of either predictability or efficiency. The efforts open a new avenue for the chaotic prediction of high-dimensional nonlinear dynamic systems.
Wideband metasurface-loaded rectenna for azimuth-insensitive electromagnetic energy absorption using characteristic mode analysis
Authors: Deng Lianwen , He Zhe-Jia , Huang Shengxiang , Qiu Lei-Lei , Zhu Lei
Published: March 2024

In this paper, a wideband metasurface-loaded (MTS-L) rectenna system is proposed to capture electromagnetic (EM) energy at arbitrary azimuth angles. The radiation patterns of different modes in the original MTS configuration are analyzed using the characteristic mode theory, and potential modes with omnidirectional radiation are screened out. By the arrangement of patches, the roundness performance of the radiation pattern can be ameliorated, and the omnidirectional characteristic is obtained over a wide frequency band. Subsequently, the surface current density of the selected mode is carefully and artificially designed to facilitate probe excitation as well as refrain from introducing complex power-combining networks. A wideband rectifier circuit is designed as the load of the proposed antenna. Eventually, measured results show that it operates from 4.6 to 9.6 GHz with a fractional bandwidth of 70.4%, and the peak system efficiency is 52.2%. The proposed system demonstrates excellent potential for wireless power transmission and EM energy harvesting in indoor environments.
Unveiling the structural and bonding properties of AuSi2− and AuSi3− clusters: A comprehensive analysis of anion photoelectron spectroscopy and ab initio calculations
Authors: Lu Sheng-Jie
Published: March 2024

Silicon clusters infused with transition metals, notably gold, exhibit distinct characteristics crucial for advancing microelectronics, catalysts, and energy storage technologies. This investigation delves into the structural and bonding attributes of gold-infused silicon clusters, specifically AuSi2− and AuSi3−. Utilizing anion photoelectron spectroscopy and ab initio computations, we explored the most stable isomers of these clusters. The analysis incorporated Natural Population Analysis, electron localization function, molecular orbital diagrams, adaptive natural density partitioning, and Wiberg bond index for a comprehensive bond assessment. Our discoveries reveal that cyclic configurations with the Au atom atop the Si–Si linkage within the fundamental Si2 and Si3 clusters offer the most energetically favorable structures for AuSi2− and AuSi3− anions, alongside their neutral counterparts. These anions exhibit notable highest occupied molecular orbital–lowest unoccupied molecular orbital gaps and significant σ and π bonding patterns, contributing to their chemical stability. Furthermore, AuSi2− demonstrates π aromaticity, while AuSi3− showcases a distinctive blend of σ antiaromaticity and π aromaticity, crucial for their structural robustness. These revelations expand our comprehension of gold-infused silicon clusters, laying a theoretical groundwork for their potential applications in high-performance solar cells and advanced functional materials.
Energy-dependent photoion angular distributions in two-body Coulomb explosions of molecules
Authors: Guo Keyu , Li Yingbin , Li Min , Cao Chuanpeng , Duan Xueqing , Liu Yang , Liu Yupeng , Li Zichen , Xu Jingkun , Zhou Yueming , Yu Benhai , Lu Peixiang
Published: March 2024

We experimentally study two-body Coulomb explosions of CO2, O2, and CH3Cl molecules in intense femtosecond laser pulses. We observe an obvious variation in the ionic angular distribution of the fragments with respect to the kinetic energy releases (KERs). Using a classical model based on ab initio potential energy curves, we find that the dependence of the ionic angular distribution on the KER is relevant to the fact that the accurate potential energy deviates significantly from the value determined by applying the Coulomb interaction approximation at a relatively small internuclear distance of the molecule. We show that the KER-dependent ionic angular distribution provides an effective way to determine the critical internuclear distance at which the Coulomb interaction approximation holds or breaks down without relying on the knowledge of the accurate potential energy curves.
The spatio-temporal distribution of aromatase cytochrome in ovary throughout the canine oestrous cycle
Authors: Lindh L. , Kowalewski M. P. , Goericke-Pesch S. K. , Lindeberg H. , Schuler G. , Peltoniemi O. A. T.
Published: March 2024

Context New animal welfare legislation and ethical guidelines encourage alternative approaches for canine contraception, instead of surgical gonadectomy which is considered invasive and unjustified in healthy dogs. Aims Reversible contraception might be achieved by inhibition of aromatase (CYP19), an enzyme catalysing the conversion of androgens to oestrogens. This study provides insights into the spatio-temporal expression and distribution of aromatase in canine ovarian tissue. Methods Ovarian tissue was collected from 39 healthy and sexually mature bitches during different stages of the oestrous cycle: pro-oestrus (n = 8), oestrus (n = 12), dioestrus (n = 9) (luteal phase) and anoestrus (n = 10). Localisation of cytochrome P450 aromatase was determined by immunohistochemistry. Key results Aromatase activity in the dog is high during pro-oestrus, ovulation and early dioestrus. Comparing types of follicles and corpora lutea, the highest aromatase abundance was found in antral follicles and luteinising follicles, whereas corpora lutea and early antral follicles showed an intermediate presence of the enzyme. Interesting was the high abundance of aromatase in luteinising theca interna cells, prevailing over granulosa cells. Conclusions and implications Understanding of cells involved in oestradiol production is important for targeted inhibition of oestradiol synthesis, possibly offering an approach for contraception and suppression of oestrus.
Habitat loss and degradation reduce the abundance of the glossy grass skink, Pseudemoia rawlinsoni
Authors: Farquhar Jules E. , Wotherspoon Lucy , Porter Hilary , Chapple David G.
Published: March 2024

Context Habitat loss and degradation are major drivers of biodiversity loss worldwide. In particular, wetland environments are being removed and degraded faster than any other terrestrial habitat on earth. The loss and degradation of wetlands has been particularly pronounced in south-eastern Australia. Aims Here we investigated the impact of habitat loss and degradation on the Data Deficient glossy grass skink (Pseudemoia rawlinsoni), a species that predominantly favours wetland vegetation in south-eastern Australia. Methods We established artificial cover-object (roofing tiles) survey grids in paired remnant and disturbed sites at six locations across Victoria, Australia, and surveyed for skinks between November 2021 and April 2022. Key results Sites at which glossy grass skinks occur are characterised by tall dense vegetation, with a high cover of matted biomass. Thermal profiles within these complex vegetation structures remain much cooler during hot days, and warmer during cold nights, than external temperatures. Nearby disturbed sites (i.e. grazed or mowed areas within dispersal distance of remnant sites) are generally devoid of skinks, have very low and structurally simple (open) vegetation, and have thermal regimes that offer lizards no respite from high summer temperatures. We found that roofing tiles are an effective way to survey for glossy grass skinks; even on cool cloudy days, the temperature of tiles, and the lizards sheltering beneath them, are often much higher than ambient temperatures. Conclusions These findings implicate habitat loss and degradation as having a substantial negative impact on glossy grass skink presence and abundance; skinks largely avoid disturbed areas, even at sites immediately adjacent to remnant habitat. This may be driven not simply by the removal of tall and dense vegetation structures, but the consequent loss of the optimal thermal buffer afforded by such structures. Implications Our study emphasises the threat that habitat loss and degradation pose to wetland species in Australia, and throughout the world.
A minimal physical model for curvotaxis driven by curved protein complexes at the cell’s leading edge
Authors: Sadhu Raj Kumar , Luciano Marine , Xi Wang , Martinez-Torres Cristina , Schröder Marcel , Blum Christoph , Tarantola Marco , Villa Stefano , Penič Samo , Iglič Aleš , Beta Carsten , Steinbock Oliver , Bodenschatz Eberhard , Ladoux Benoît , Gabriele Sylvain , Gov Nir S.
Published: March 2024

Cells often migrate on curved surfaces inside the body, such as curved tissues, blood vessels, or highly curved protrusions of other cells. Recent in vitro experiments provide clear evidence that motile cells are affected by the curvature of the substrate on which they migrate, preferring certain curvatures to others, termed “curvotaxis.” The origin and underlying mechanism that gives rise to this curvature sensitivity are not well understood. Here, we employ a “minimal cell” model which is composed of a vesicle that contains curved membrane protein complexes, that exert protrusive forces on the membrane (representing the pressure due to actin polymerization). This minimal-cell model gives rise to spontaneous emergence of a motile phenotype, driven by a lamellipodia-like leading edge. By systematically screening the behavior of this model on different types of curved substrates (sinusoidal, cylinder, and tube), we show that minimal ingredients and energy terms capture the experimental data. The model recovers the observed migration on the sinusoidal substrate, where cells move along the grooves (minima), while avoiding motion along the ridges. In addition, the model predicts the tendency of cells to migrate circumferentially on convex substrates and axially on concave ones. Both of these predictions are verified experimentally, on several cell types. Altogether, our results identify the minimization of membrane-substrate adhesion energy and binding energy between the membrane protein complexes as key players of curvotaxis in cell migration.
The temporal and genomic scale of selection following hybridization
Authors: Groh Jeffrey S. , Coop Graham
Published: March 2024

Genomic evidence supports an important role for selection in shaping patterns of introgression along the genome, but frameworks for understanding the evolutionary dynamics within hybrid populations that underlie these patterns have been lacking. Due to the clock-like effect of recombination in hybrids breaking up parental haplotypes, drift and selection produce predictable patterns of ancestry variation at varying spatial genomic scales through time. Here, we develop methods based on the Discrete Wavelet Transform to study the genomic scale of local ancestry variation and its association with recombination rates and show that these methods capture temporal dynamics of drift and genome-wide selection after hybridization. We apply these methods to published datasets from hybrid populations of swordtail fish (
Xiphophorus
) and baboons (
Papio
) and to inferred Neanderthal introgression in modern humans. Across systems, upward of 20% of variation in local ancestry at the broadest genomic scales can be attributed to systematic selection against introgressed alleles, consistent with strong selection acting on early-generation hybrids. Signatures of selection at fine genomic scales suggest selection over longer time scales; however, we suggest that our ability to confidently infer selection at fine scales is likely limited by inherent biases in current methods for estimating local ancestry from contiguous segments of genomic similarity. Wavelet approaches will become widely applicable as genomic data from systems with introgression become increasingly available and can help shed light on generalities of the genomic consequences of interspecific hybridization.
Dependence on relative humidity in the formation of reactive oxygen species in water droplets
Authors: Mofidfar Mohammad , Mehrgardi Masoud A. , Xia Yu , Zare Richard N.
Published: March 2024

Water microdroplets (7 to 11 µm average diameter, depending on flow rate) are sprayed in a closed chamber at ambient temperature, whose relative humidity (RH) is controlled. The resulting concentration of ROS (reactive oxygen species) formed in the microdroplets, measured by the amount of hydrogen peroxide (H
2
O
2
), is determined by nuclear magnetic resonance (NMR) and by spectrofluorimetric assays after the droplets are collected. The results are found to agree closely with one another. In addition, hydrated hydroxyl radical cations (•OH-H
3
O
+
) are recorded from the droplets using mass spectrometry and superoxide radical anions (•O
2
−
) and hydroxyl radicals (•OH) by electron paramagnetic resonance spectroscopy. As the RH varies from 15 to 95%, the concentration of H
2
O
2
shows a marked rise by a factor of about 3.5 in going from 15 to 50%, then levels off. By replacing the H
2
O of the sprayed water with deuterium oxide (D
2
O) but keeping the gas surrounding droplets with H
2
O, mass spectrometric analysis of the hydrated hydroxyl radical cations demonstrates that the water in the air plays a dominant role in producing H
2
O
2
and other ROS, which accounts for the variation with RH. As RH increases, the droplet evaporation rate decreases. These two facts help us understand why viruses in droplets both survive better at low RH values, as found in indoor air in the wintertime, and are disinfected more effectively at higher RH values, as found in indoor air in the summertime, thus explaining the recognized seasonality of airborne viral infections.
Frequent winners explain apparent skewness preferences in experience-based decisions
Authors: Olschewski Sebastian , Spektor Mikhail S. , Le Mens Gaël
Published: March 2024

Do people’s attitudes toward the (a)symmetry of an outcome distribution affect their choices? Financial investors seek return distributions with frequent small returns but few large ones, consistent with leading models of choice in economics and finance that assume right-skewed preferences. In contrast, many experiments in which decision-makers learn about choice options through experience find the opposite choice tendency, in favor of left-skewed options. To reconcile these seemingly contradicting findings, the present work investigates the effect of skewness on choices in experience-based decisions. Across seven studies, we show that apparent preferences for left-skewed outcome distributions are a consequence of those distributions having a higher value in most direct outcome comparisons, a “frequent-winner effect.” By manipulating which option is the frequent winner, we show that choice tendencies for frequent winners can be obtained even with identical outcome distributions. Moreover, systematic choice tendencies in favor of right- or left-skewed options can be obtained by manipulating which option is experienced as the frequent winner. We also find evidence for an intrinsic preference for right-skewed outcome distributions. The frequent-winner phenomenon is robust to variations in outcome distributions and experimental paradigms. These findings are confirmed by computational analyses in which a reinforcement-learning model capturing frequent winning and intrinsic skewness preferences provides the best account of the data. Our work reconciles conflicting findings of aggregated behavior in financial markets and experiments and highlights the need for theories of decision-making sensitive to joint outcome distributions of the available options.
The power of language
Authors: Gabsi Zouhir
Published: March 2024

One of the most overlooked areas of study in the post-Arab Spring narrative is the symbiotic relationship between
language and politics. Framed by the micro and macro-level approaches to discourse, the paper’s scope is twofold. First, it
identifies and discusses how language elements underpin the performative role of language (Austin 1975 [1962]) and considers Searle’s (1969) work on speech-acts and
rhetoric through irony and metaphor. Second, it discusses how the study of language, through power and ideology, provides a candid
and deeper understanding of Tunisian politics; an ‘internal’ perspective on how participants in these discourses perceive the
Tunisian people, society, culture, and politics, reflecting on a decade since the revolution. The paper hinges on various textual
genres, such as televised interviews, debates, and rap songs, sampling some emerging new sociopolitical spaces wherein, through
discursive themes, participants address Tunisia’s political and economic grievances since the revolution.