bluuebunny/crossref_metadata_2025 huggingface dataset:
Haters in the spotlight
Authors: Pahor de Maiti Kristina , Franza Jasmin , Fišer Darja
Published: October 2023

This study investigates the interplay between commenters’ gender and their language use in Slovene socially unacceptable Facebook comments by inspecting the frequency of opinion markers and impoliteness triggers, and the pragmatic functions of opinion markers which were investigated according to a newly developed typology. The analysis shows statistically significant differences between men and women in their formulation of opinions and use of impoliteness triggers. Comments written by men are characteristically formed as fact-like covert opinions and contain explicit impoliteness triggers (e.g., insults). Comments written by women are formed as overt opinions explicitly encoding subjectivity and include implicit impoliteness triggers (e.g., tropes). A common feature is the use of opinion markers as self-oriented face-saving devices. But while men use opinion markers to explicitly communicate their desire to save face, women use them to perform face-saving implicitly.
On the etymology and distribution of verb forms in Arabic-based pidgins
Authors: Louhichi Imed
Published: October 2023

In this paper, we add to the body of existing literature on Arabic-based pidgins. We focus on the verbal system because the structure of this phrasal category and how it is used in discourse remain inconclusive. For instance, while some claim these speakers prefer the imperfective form which is marked for male third person singular (e.g.y-iji‘3sg.m-come.ipf’), others claim it is the imperative that is most preferred (e.g.rūh‘2.sg.m-go.imp’). Equally, while some argue the choice between either verb forms is pragmatically motivated, others claim it is phonologically motivated. To add to this mix, a third group claims there is a systematic division of labor in that non-state verbs usually follow the prefixed type while the state verbs follow the unprefixed type.

We evaluate these proposals. Analysis of ‘frog story’ narratives by 10 GPA speakers in the United Arab Emirates reveal the prefixed form to be the most preferred and this preference is influenced by the contriving of phonological, semantic, and pragmatic factors. Frequency as well as item-based analogy as understood within usage-based theories of learning provide a viable framework in which the apparent inconsistencies between the competing proposals are resolved.
Localized cardiomyocyte lipid accumulation is associated with slowed epicardial conduction in rats
Authors: Wells Simon P. , Raaijmakers Antonia J.A. , Curl Claire L. , O’Shea Christopher , Hayes Sarah , Mellor Kimberley M. , Kalman Jonathan M. , Kirchhof Paulus , Pavlovic Davor , Delbridge Lea M.D. , Bell James R.
Published: October 2023

Transmural action potential duration differences and transmural conduction gradients aid the synchronization of left ventricular repolarization, reducing vulnerability to transmural reentry and arrhythmias. A high-fat diet and the associated accumulation of pericardial adipose tissue are linked with conduction slowing and greater arrhythmia vulnerability. It is predicted that cardiac adiposity may more readily influence epicardial conduction (versus endocardial) and disrupt normal transmural activation/repolarization gradients. The aim of this investigation was to determine whether transmural conduction gradients are modified in a rat model of pericardial adiposity. Adult Sprague-Dawley rats were fed control/high-fat diets for 15 wk. Left ventricular 300 µm tangential slices were generated from the endocardium to the epicardium, and conduction was mapped using microelectrode arrays. Slices were then histologically processed to assess fibrosis and cardiomyocyte lipid status. Conduction velocity was significantly greater in epicardial versus endocardial slices in control rats, supporting the concept of a transmural conduction gradient. High-fat diet feeding increased pericardial adiposity and abolished the transmural conduction gradient. Slowed epicardial conduction in epicardial slices strongly correlated with an increase in cardiomyocyte lipid content, but not fibrosis. The positive transmural conduction gradient reported here represents a physiological property of the ventricular activation sequence that likely protects against reentry. The absence of this gradient, secondary to conduction slowing and cardiomyocyte lipid accumulation, specifically in the epicardium, indicates a novel mechanism by which pericardial adiposity may exacerbate ventricular arrhythmias.
On the microstructure of higher-dimensional Reissner–Nordström black holes in quantum regime
Authors: Masood A S Bukhari Syed , Pourhassan Behnam , Aounallah Houcine , Wang Li-Gang
Published: October 2023

Thermodynamic Riemannian geometry provides great insights into the microscopic structure of black holes (BHs). One such example is the Ruppeiner geometry which is the metric space comprising the second derivatives of entropy with respect to other extensive variables of the system. Reissner–Nordström black holes (RNBHs) are known to be endowed with a flat Ruppeiner geometry for all higher spacetime dimensions. However this holds true if one invokes classical gravity where the semi-classical Bekenstein–Hawking entropy best describes the thermodynamics of the system. If the much deeper quantum gravity and string theories entail modifications to BH entropy, this prompts the question whether the Ruppeiner flatness associated with higher dimensional RNBHs still persists. We investigate this problem by considering non-perturbative (exponential) and perturbative (logarithmic) modifications to BH entropy of a 5D RNBH. We find that while the case is so for larger (classical) geometries, the situation is radically altered for smaller (quantum) geometries. Namely, we show surprising emergence of multiple phase transitions that depend on the choice of extent of corrections to BH entropy and charge. Our consideration involves differentiated extremal and non-extremal geometric scales corresponding to the validity regime of corrections to entropy. More emphasis is laid on the exponential case as the contributions become highly non-trivial on small scales. An essential critical mass scale arises in this case that marks the onset of these phase transitions while the BH diminishes in size via Hawking evaporation. We contend that this critical value of mass perhaps best translates as the epoch of a classical to quantum BH phase transition.
Modeling of experimentally observed topological defects inside bulk polycrystals
Authors: Singh Siddharth , Liu He , Arora Rajat , Suter Robert M , Acharya Amit
Published: October 2023

A rigorous methodology is developed for computing elastic fields generated by experimentally observed defect structures within grains in a polycrystal that has undergone tensile extension. An example application is made using a near-field high energy x-ray diffraction microscope measurement of a zirconium sample that underwent

13.6
%

tensile extension from an initially well-annealed state. (Sub)grain boundary features are identified with apparent disclination line defects in them. The elastic fields of these features identified from the experiment are calculated.
Multistep optimization for the electrodeposited mixed perovskite FA1−y
Cs
y
PbBr
x
I3−x
solar cells
Authors: Xiang Yanhong , Zheng Ren , Li Chunhe , Ren Kuankuan , Ye Qiufeng , Shi Biyun , Liu Shiyan , Fang Zebo
Published: October 2023

The electrodeposition method has recently been developed for the fabrication of perovskite solar cells due to its potential advantages in commercial preparation. However, there is few studies on the preparation of perovskite solar cells by the electrodeposition method, especially on the perovskite FAPbI3-based solar cells. Herein, we fabricated the mixed perovskite FA1−y
Cs
y
PbBr
x
I3−x
solar cells by an optimized electrodeposition method, in which the electrodeposited PbO2 reacts directly with FAI and an appropriate amount of CsBr dopants. The corresponding solar cells display the best PCE of 4.97%. By regulating the growth temperature in the reaction between PbO2 and FAI/CsBr, the efficiency of the mixed perovskite solar cells can be promoted to 10.18%. These results illustrate that the element doping and growth environment regulation can optimize the quality of the perovskite films, thus promoting the efficiency of the perovskite solar cells. With further optimizing the growth process in the electrodeposition method, it is expected to open up a new commercial preparation route for the perovskite solar cells in the near future.
High temperature superconducting CORC cable with variable winding angles for low AC loss and high current carrying SMES system
Authors: Zheng Jinxing , Cheng Yuan , Li Ming , Liu Fei , Liu Xufeng , Liu Haiyang
Published: October 2023

Owing to the rising demand for enhanced high-current capacity within superconducting magnetic energy storage (SMES) system used in power grids, there is a growing focus on enhancing the current-carrying capability of SMES setups wound with conductor on round core (CORC) cables. However, it is crucial to note that the dissipation of AC losses in CORC cables during rapid charge and discharge cycles can substantially impact the safe operation of SMES. The CORC cable is crafted by spirally winding numerous ReBCO tapes around copper tubes. Even slight alterations in the winding angles of these tapes can result in shifts at current distribution across the ReBCO tapes, thus leading to differences in AC losses. Hence, the primary objective of this paper is to study the effect of varying winding angles of each ReBCO layer on AC loss. The adoption of variable angles results in the reduction of current flowing through the outermost tapes. And the AC losses in the outermost tapes happen to account for the majority of the total AC losses. Through simulations and experiments, it was observed that the AC loss in the CORC cable with variable angles (4 × 12, 25°–40°) was 25% lower than that in the case of fixed angles (3 × 11, 45°). These findings demonstrate a noteworthy downward trajectory in AC losses when variable angles are applied to the CORC cable. These insights hold significant value for the practical application of CORC cables within SMES systems.
Connector effects and reference plane influence in the N-Type connector
Authors: Gellersen F , Rausche F , Wissel A , Kuhlmann K
Published: October 2023

In this paper we outline the impact of mixing slotted N-type and slotless N-type connectors during a vector network analyzer calibration. We want to point out that making precise measurements of typical transfer standards, while using both N-type jack connectors is very difficult, because of the reference plane shift. We performed simulations of the two connector jack geometries to estimate the impact on measurements of devices under test with either plug or jack interface. The influence of mixing slotted and slotless connectors is then validated through simple measurements, which can be easily repeated in many labs. The results show that mixing of slotted and slotless jacks adds errors in the same order of magnitude sometimes reported as measurement uncertainties by national metrology institutes.
Numerical Simulation on Near-water-surface Skipping Motion of Trans-media Vehicle
Authors: Ma Wenxuan , Zhang Hangwei , Hu Ziye , Sa Haijing , Zhang Wenyi
Published: October 2023

When a trans-media vehicle impacts the water surface at a small angle, it will bounce and take off and then re-enter the water, which is called near-water-surface Skipping Motion. The study of this kind of movement is of great significance to the high maneuvering penetration of ships or aircraft near sea level. This paper adopted the method of numerical simulation, selected the SST k-ω turbulence model, combining the N-S equation and the six-degree-of-freedom (6DOF) algorithm, and used the overall dynamic grid technology to calculate the vehicle entry condition at speed of 50m/s, 100m/s, 150m/s &10°, 20°, 30° angle of attack, and the near-water-surface skipping motion characteristics of the vehicle were explored, which provided a reference for studying the high maneuvering motion of offshore plane trans-media vehicles.
The influence of the grooved fairing dimension on the AUVs for across-medium flight
Authors: Zhao Yu , Zhang Zhiyuan , Ma Guangsong , Chang Yukun , Guo Qianwei
Published: October 2023

The research object of this paper is the across medium (air and water) Autonomous Underwater Vehicles (AUVs) fairing. When the AUVs are flying in the air, for the purpose of protecting the detection equipment and reducing the air resistance, an ogive fairing is installed at the head of the aircraft. When the AUVs enter the water at a certain angle and speed after arriving at the destination, it is hoped that the fairing will be broken as much as possible, so that it does not affect the normal use of the detection equipment. Therefore, the influence of the dimension parameters of the fairing on the aerodynamic resistance is studied, and the influence of the groove and groove depth on the damage of the fairing after impact is also researched.
Numerical simulation of pulverized coal combustion in a 660MW tangentially fired boiler with fuel variation
Authors: Fang Jiuwen , Li Mingxin , Gao Baosheng , Zeng Yuqin , Zhang Lingcan , Qiao Jiawei , Jie Xinshi , Xiao Xianbin
Published: October 2023

To study the effects of various coal properties on the combustion characteristics during actual operation, and on the high temperature corrosion of the water wall. The paper presents a numerical simulation of a 660MW boiler using ANSYS FLUENT software. Three cases were investigated with various fuel properties: (1) the designed coal NO.1, (2) the non-designed coal NO.2 with high ash, high sulphur content and low volatile matter, (3) the blended fuel of coal NO.3with similar coal quality to the coal NO.1 and NO.4 with high sulphur content. Simulation results indicate that blended coal feeding can improve the combustion characteristics of poor-quality coals. It provides a theoretical reference for the actual operation of power plants with non-designed coals.
Study on jet formation and penetration performance of shaped charge with untypical double-cone titanium liner
Authors: Li Hongda , Li Peipei , Duan Hui , Zhang Zhili
Published: October 2023

Based on the platform of AUTODYN-2D code, the shaped charge with untypical double-cone titanium liner penetrating concrete targets are investigated. The influence of the titanium liner thickness and the height ratio of top cone on the jet tip-velocity and jet characteristics are analyzed. The titanium liner thickness, the height ratio of top cone, and the standoff affecting on the penetration performance of the concrete targets are also conducted. The numerical simulations indicated that, with increasing the titanium liner thickness, the jet tip-velocity gradually decreased, and the penetration depth of the concrete targets first increased and then decreased. When the height ratio of top cone was 0.5, the shaped charge with untypical double-cone titanium liner can combine the advantage of the small cone-angle liner and the large cone-angle liner, which will ensure the sufficient penetration depth and hole diameter. Furthermore, the shaped charge with untypical double-cone titanium liner can penetrate the concrete with a thickness of 1000mm at the standoff within a region between 2.0 CD and 2.5 CD.
Coupled CFD-DEM simulation of submarine landslide movement behavior
Authors: Li Ziyi , Song Wanqiang
Published: October 2023

Submarine landslide is a common disaster geological phenomenon in the ocean, which can be destructive to underwater infrastructure. Therefore, it is necessary to simulate the evolutionary behavior of submarine viscous landslides. In this paper, computational fluid dynamics (CFD) and discrete element method (DEM) are used to establish the fluid-solid coupling model of water-particle interaction. Firstly, the inter-particle cohesion model is introduced to train the coupled CFD-DEM analysis of the kinematic evolution process, and at the same time, two typical cases are carried out to verify the analysis. In the experimental simulation, the kinematic and morphological characteristics of the submarine landslide were simulated considering the viscous effect and initial velocity of the landslide, and the influence mechanism of the landslide motion and evolution process was investigated in depth. The results show that the coupled method can better simulate the motion of submarine landslide, and the viscous effect of the landslide has a significant influence on its kinematic and morphological characteristics, and the initial velocity also significantly affects the evolution and distribution characteristics of the particle flow field of each part of the landslide in the process of motion. This study is important for the simulation and effective prediction of the kinematic evolution process of real submarine landslides.
Numerical simulation of the leading edge bump for the cavity flow
Authors: Li Wei , Meng Dehong , Hong Junwu , Wang Hao
Published: October 2023

Based on the IDDES method, the M219 cavity is simulated in flux-mixed scheme, with the main purpose of studying the mechanism of the noise generation in the cavity flow and proposing corresponding suppression measures. The study mainly includes the grid resolution study and the numerical simulation of the leading edge bump. Through the comparative analysis with the experimental results provided by Henshaw et al. and the LES results from Haase et al. it is known that the different grids in this paper can all obtain the flow characteristics of the cavity flow, and the different grids show the convergence. The leading edge bump can significantly raise the shear layer, reduce the disturbance flowing into the cavity, and play a role in suppressing both the cavity tones and the broadband of the cavity flow.
Simulation on Evaporation and Cooling Characteristics of Spray System
Authors: Chang Tingting , Wang Chun , Wang Fuqing , Wang Kun
Published: October 2023

This study explored the evaporation and cooling characteristics of air pipeline spray based on computational fluid dynamics method. A geometric model of the pipeline air spray was constructed and meshed, and the Euler-Lagrange research method of the discrete phase model (DPM) was used to study the evaporation and cooling characteristics of the spray system. It was found that the length required for complete evaporation of droplets increased with the relative humidity. When the inlet temperature was 308K and the relative humidity was 40%, the evaporation length increased by 43.71% compared to when it was 20%. There was a negative correlation between the inlet temperature and the evaporation length, and when the relative humidity was 30%, the evaporation length at an inlet temperature of 323K decreased by 1.55m compared to when it was 313K. After spraying, the air temperature gradually decreased along the length of the pipe, and the cooling effect decreased as the relative humidity of the inlet air increased. When the inlet temperature was 308K and the relative humidity was 40%, the outlet temperature was 4.39K higher than when it was 20%, and the cooling effect increased as the inlet air temperature increased. When the relative humidity of the inlet air was 30%, the temperature drop at the outlet at an inlet temperature of 323K was 1.93K higher than when it was 313K.
Numerical simulation and wind tunnel experiment on aerodynamic characteristics of an electric aircraft
Authors: Wang Kaijing
Published: October 2023

Taking an electric aircraft with high aspect ratio as the object of research, the CFD numerical simulation based on Navier-Stokes calculation and Spalart-Allmaras onflow pattern is conducted to verify the aerodynamic design and evaluate the flight property and quality of aircraft. With the aim of verifying the reasonability of the CFD calculation, a wind tunnel experiment was conducted for evaluation. The results indicate that the simulation information coincide well with wind tunnel test data, indicating that the simulation method could provide a guidance for the aerodynamic design of electric aircrafts, especially those with high aspect ratio.
Research on microstructure and properties of 3D plasma spray welding repair layer of continuous casting segmented rollers
Authors: Li Yuxiang , Zhou Ying , Meng Zhengbing , Liu Xiao , Zhang Xin , Chen Yuanyu , Shen Jialong , Liao Jiachi
Published: October 2023

In this paper, the Fe-Cr-Ni-Si powder was used in a 3D plasma spray welding machine to perform spray welding repair tests on continuous casting segmented rollers for service life improvement. The phase composition, hardness distribution, abrasion resistance and thermal stability of the spray welding layer were analyzed. Results indicated that the spray welding layer produced by 160 A welding current was more uniform and was with finer organization. The main phase zone was a single γ-Fe and the fusion zone was metallurgically combined with the base metal in a planar grain manner. The hardness of the spray welding layer was the maximum when the welding current was 160 A. The abrasion resistance for each position of the spray welding layer was uniform. The γ-Fe phase zone decreased and the α-Fe phase zone increased with reduction of average hardness after the thermal stability test. In industrial tests, the optimum spray welding parameters were verified and the service life of the continuous casting segmented rollers with spray welding was 2 longer than rollers using surfacing welding process.
Analysing active power reserve strategies for photovoltaic systems under varying shading scenarios: a comparative study
Authors: Verma Pankaj , Katal Nitish
Published: October 2023

The installed capacity of grid-connected solar photovoltaic (PV) systems is increasing rapidly; therefore, in the near future, the total system inertia may possibly decrease. Reserving some active power in PV systems is crucial to manage the problem of low inertia. In this paper, we critically analyse and compare the performances of several active power reserve and frequency regulation techniques for PV systems. The discussed techniques do not use energy storage devices and are aimed at enabling the inertial capabilities of PV systems. These techniques are broadly classified according to the shading conditions and methodologies adopted for reserve generation. In this paper, we closely investigate different deloading techniques used in PV systems. In deloading, PV systems are operated at a voltage distant from the maximum power point. Further, we also address the effectiveness and suitability of the aforementioned techniques under different operating conditions. Through this review paper, we aim to provide a one-stop reference for PV researchers to select appropriately from the available reserve techniques for designing flexible DC–DC controls for PV systems.
Enhanced independent component analysis and fuzzy C-mean clustering based on novel bat algorithm for noisy image segmentation
Authors: Chetih Nabil , Thelaidjia Tawfik , Boudani Fatma Zohra
Published: October 2023

Fuzzy c-means clustering is widely recognized as one of the most effective methods for image segmentation and achieving accurate classification. However, this method has two significant drawbacks: its sensitivity to noise and its convergence to local minimum clusters’ centroids. In this paper, we proposed a novel model called EIFCMNB, which incorporates enhanced independent component analysis (EICA), fuzzy c-means clustering (FCMC) and novel bat algorithm (NBA) for noise image segmentation. The suggested model consists of two main phases: image denoising and extraction of the regions of interest (ROIs). In the first phase, the enhanced independent component analysis (EICA) algorithm is used for recovering a good quality image, from a noisy image of poor quality. Several noisy images, with noise variances ranging from 5 to 20, were filtered. The resulting images were then evaluated based on several criteria viz: Peak Signal to Noise Ratio (PSNR), Relative Norm Error (RE), Normalized Cross-Correlation (NCC), and Structural Similarity index measure (SSIM). In the second phase, the fuzzy c-means clustering based on a novel bat algorithm is adopted to calculate optimal clusters’ centroids and extract the ROIs. By incorporating the new bat algorithm, we aim to overcome the problem of converging to local minimums and achieve improved segmentation accuracy. Promising experimental results have been obtained by applying the proposed model to MRI brain images and x-ray welding images. Two criteria viz: VPE end VPC have been employed to evaluate the suggested approach. The experiments clearly demonstrate that our suggested model effectively addresses the sensitivity to noise problem and provides optimal clusters’ centroids. Moreover, it outperforms several FCMC-based algorithms, exhibiting superior performance in terms of image segmentation and classification.
Governing equation discovery based on causal graph for nonlinear dynamic systems
Authors: Jia Dongni , Zhou Xiaofeng , Li Shuai , Liu Shurui , Shi Haibo
Published: October 2023

The governing equations of nonlinear dynamic systems is of great significance for understanding the internal physical characteristics. In order to learn the governing equations of nonlinear systems from noisy observed data, we propose a novel method named governing equation discovery based on causal graph that combines spatio-temporal graph convolution network with governing equation modeling. The essence of our method is to first devise the causal graph encoding based on transfer entropy to obtain the adjacency matrix with causal significance between variables. Then, the spatio-temporal graph convolutional network is used to obtain approximate solutions for the system variables. On this basis, automatic differentiation is applied to obtain basic derivatives and form a dictionary of candidate algebraic terms. Finally, sparse regression is used to obtain the coefficient matrix and determine the explicit formulation of the governing equations. We also design a novel cross-combinatorial optimization strategy to learn the heterogeneous parameters that include neural network parameters and control equation coefficients. We conduct extensive experiments on seven datasets from different physical fields. The experimental results demonstrate the proposed method can automatically discover the underlying governing equation of the systems, and has great robustness.
Presymplectic gauge PDEs and Lagrangian BV formalism beyond jet-bundles
Authors: Grigoriev Maxim
Published: October 2023

A gauge PDE is a geometrical object underlying what physicists call a local gauge field theory defined at the level of equations of motion (i.e. without specifying Lagrangian) in terms of Batalin-Vilkovisky (BV) formalism. This notion extends the BV formulation in terms of jet-bundles on the one hand and the geometrical approach to PDEs on the other hand. In this work we concentrate on gauge PDEs equipped with a compatible presymplectic structure and show that under some regularity conditions this data defines a jet-bundle BV formulation. More precisely, the BV jet-bundle arises as the symplectic quotient of the super jet-bundle of the initial gauge PDE. In this sense, presymplectic gauge PDEs give an invariant geometrical approach to Lagrangian gauge systems, which is not limited to jet-bundles. Furthermore, the presymplectic gauge PDE structure naturally descends to space-time submanifolds (in particular, boundaries, if any) and, in this respect, is quite similar to AKSZ sigma models which are long known to have this feature. We also introduce a notion of a weak presymplectic gauge PDE, where the nilpotency of the differential is replaced by a presymplectic analog of the BV master equation, and show that it still defines a local BV system. This allows one to encode BV systems in terms of finite-dimensional graded geometry, much like the AKSZ construction does in the case of topological models.
Invasive macroalgae in native seagrass beds: vectors of spread and impacts
Authors: Firth Louise B , Foggo Andy , Watts Thomas , Knights Antony M , deAmicis Stacey
Published: October 2023

Background and Aims

Worldwide, invasive species are spreading through marine systems at an unprecedented rate with both positive and negative consequences for ecosystems and the biological functioning of organisms. Human activities from shipping to habitat damage and modification are known vectors of spread, although biological interactions including epibiosis are increasingly recognized as potentially important to introduction into susceptible habitats.

Methods

We assessed a novel mechanism of spread – limpets as transporters of an invasive alga, Sargassum muticum, into beds of the seagrass Zostera marina – and the physiological impact of its invasion. The association of S. muticum with three limpet species and other habitats was assessed using intertidal surveys on rocky shores and snorkelling at two seagrass sites in the UK. A 4-year field study tested the effect of S. muticum on Z. marina shoot density, dry weight and phenolic compounds (caffeic and tannic acid) content, and a laboratory experiment tested the impact of S. muticum on nutrient partitioning (C/H/N/P/Si), photosynthetic efficiency (Fv/Fm) and growth of Z. marina.

Results

On rocky shores 15 % of S. muticum occurrences were attached to the shells of live limpets. In seagrass beds 5 % of S. muticum occurrences were attached to the shells of dead limpets. The remainder were attached to rock, to cobblestones, to the seagrass matrix or embedded within the sand. Z. marina density and phenolics content was lower when S. muticum co-occurred with it. Over 3 years, photosynthetic responses of Z. marina to S. muticum were idiosyncratic, and S. muticum had no effect on nutrient partitioning in Z. marina.

Conclusions

Our results show limpets support S. muticum as an epibiont and may act as a previously unreported transport mechanism introducing invaders into sensitive habitats. S. muticum reduced production of phenolics in Z. marina, which may weaken its defensive capabilities and facilitate proliferation of S. muticum. The effect of S. muticum on Z. marina photosynthesis requires further work but having no effect on the capacity of Z. marina to sequester nutrients suggests a degree of resilience to this invader.
Noradrenergic alterations in Parkinson’s disease: a combined 11C-yohimbine PET/neuromelanin MRI study
Authors: Laurencin Chloé , Lancelot Sophie , Brosse Sarah , Mérida Inés , Redouté Jérôme , Greusard Elise , Lamberet Ludovic , Liotier Véronique , Le Bars Didier , Costes Nicolas , Thobois Stéphane , Boulinguez Philippe , Ballanger Bénédicte
Published: October 2023

Degeneration of the noradrenergic system is now considered a pathological hallmark of Parkinson’s disease, but little is known about its consequences in terms of parkinsonian manifestations. Here, we evaluated two aspects of the noradrenergic system using multimodal in vivo imaging in patients with Parkinson’s disease and healthy controls: the pigmented cell bodies of the locus coeruleus with neuromelanin sensitive MRI; and the density of α2-adrenergic receptors (ARs) with PET using 11C-yohimbine.

Thirty patients with Parkinson’s disease and 30 age- and sex-matched healthy control subjects were included. The characteristics of the patients’ symptoms were assessed using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). Patients showed reduced neuromelanin signal intensity in the locus coeruleus compared with controls and diminished 11C-yohimbine binding in widespread cortical regions, including the motor cortex, as well as in the insula, thalamus and putamen. Clinically, locus coeruleus neuronal loss was correlated with motor (bradykinesia, motor fluctuations, tremor) and non-motor (fatigue, apathy, constipation) symptoms. A reduction of α2-AR availability in the thalamus was associated with tremor, while a reduction in the putamen, the insula and the superior temporal gyrus was associated with anxiety.

These results highlight a multifaceted alteration of the noradrenergic system in Parkinson’s disease since locus coeruleus and α2-AR degeneration were found to be partly uncoupled. These findings raise important issues about noradrenergic dysfunction that may encourage the search for new drugs targeting this system, including α2-ARs, for the treatment of Parkinson’s disease.
Unravelling the genomic features, phylogeny and genetic basis of tooth ontogenesis in Characiformes through analysis of four genomes
Authors: Yang Xianwei , Song Yue , Zhang Rui , Yu Mengjun , Guo Xinyu , Guo Haobing , Du Xiao , Sun Shuai , Li Chunhua , Mao Xuebin , Fan Guangyi , Liu Xin
Published: October 2023

Characiformes is a diverse and evolutionarily significant order of freshwater fish encompassing over 2,300 species. Despite its diversity, our understanding of Characiformes’ evolutionary relationships and adaptive mechanisms is limited due to insufficient genome sequences. In this study, we sequenced and assembled the genomes of four Characiformes species, three of which were chromosome-level assemblies. Our analyses revealed dynamic changes in gene family evolution, repeat sequences and variations in chromosomal collinearity within these genomes. With the assembled genomes, we were not only able to elucidate the evolutionary relationship of the four main orders in Otophysi but also indicated Characiformes as the paraphyletic group. Comparative genomic analysis with other available fish genomes shed light on the evolution of genes related to tooth development in Characiformes. Notably, variations in the copy number of secretory calcium-binding phosphoproteins (SCPP) genes were observed among different orders of Otophysi, indicating their potential contribution to the diversity of tooth types. Our study offers invaluable genome sequences and novel insights into Characiformes’ evolution, paving the way for further genomic and evolutionary research in fish.
A preoperative computed tomography radiomics model to predict disease-free survival in patients with pancreatic neuroendocrine tumors
Authors: Homps Margaux , Soyer Philippe , Coriat Romain , Dermine Solène , Pellat Anna , Fuks David , Marchese Ugo , terris Benoit , Groussin Lionel , Dohan Anthony , Barat Maxime
Published: October 2023

Importance

Imaging has demonstrated capabilities in the diagnosis of pancreatic neuroendocrine tumors (pNETs), but its utility for prognostic prediction has not been elucidated yet.

Objective

The aim of this study was to build a radiomics model using preoperative computed tomography (CT) data that may help predict recurrence-free survival (RFS) or OS in patients with pNET.

Design

We performed a retrospective observational study in a cohort of French patients with pNETs.

Participants

Patients with surgically resected pNET and available CT examinations were included.

Interventions

Radiomics features of preoperative CT data were extracted using 3D-Slicer® software with manual segmentation. Discriminant features were selected with penalized regression using least absolute shrinkage and selection operator method with training on the tumor Ki67 rate (≤2 or >2). Selected features were used to build a radiomics index ranging from 0 to 1.

Outcome and measure

A receiving operator curve was built to select an optimal cutoff value of the radiomics index to predict patient RFS and OS. Recurrence-free survival and OS were assessed using Kaplan–Meier analysis.

Results

Thirty-seven patients (median age, 61 years; 20 men) with 37 pNETs (grade 1, 21/37 [57%]; grade 2, 12/37 [32%]; grade 3, 4/37 [11%]) were included. Patients with a radiomics index >0.4 had a shorter median RFS (36 months; range: 1-133) than those with a radiomics index ≤0.4 (84 months; range: 9-148; P = .013). No associations were found between the radiomics index and OS (P = .86).
Dynamic changes of left atrial substrate over time following pulmonary vein isolation: the Progress-AF study
Authors: Marcon Lorenzo , Bergonti Marco , Spera Francesco , Saenen Johan , Huybrechts Wim , Miljoen Hielko , Van Leuven Olivier , Vandaele Lien , Wittock Anouk , Heidbuchel Hein , Sarkozy Andrea
Published: October 2023

Aims

Little is known about dynamic changes of the left atrial (LA) substrate over time in patients with atrial fibrillation (AF). This study aims to evaluate substrate changes following pulmonary vein isolation (PVI).

Methods and results

In our prospective observational study, consecutive patients undergoing first PVI-only and redo ablation were included. High-density maps of the two procedures were compared. Progression or regression was diagnosed if a significant concordant decrease or increase in bipolar voltages in ≥2 segments was observed, respectively. In 28 patients (61.2 ± 9.5 years, 39% female, 53.5% persistent AF), 111.013 voltage points from 56 high-density LA maps (1.982 points/patient) were analysed. Comparing the high-density maps of the first and second procedures, in the progression group (17 patients, 61%), there was a decrease in global (−35%, P < 0.001) and all regional voltages. In the regression group (11 patients, 39%), there was an increase in global (+43%, P < 0.001) and regional voltages. Comparing the progression with the regression group, the area of low-voltage zone (LVZ) increased (+3.5 vs. −4.5 cm2, P < 0.001) and LA activation time prolonged (+8.0 vs. −9.1 ms, P = 0.005). Baseline clinical parameters did not predict progression or regression. In patients with substrate progression, pulmonary veins (PVs) were more frequently isolated (P = 0.02) and the AF pattern at recurrence was more frequently persistent (P = 0.005).

Conclusion

Our study describes bidirectional dynamic properties of the LA substrate with concordant either progressive or regressive changes. Regression occurs with reduced AF burden after the first procedure, while progression is associated with persistent AF recurrence despite durable PV isolation. The dynamic nature of LA substrate poses questions about LVZ-based ablation strategies.
Orthologs of the Caenorhabditis elegans heterochronic genes have divergent functions in Caenorhabditis briggsae
Authors: Ivanova Maria , Moss Eric G
Published: October 2023

The heterochronic genes of Caenorhabditis elegans comprise the best-studied pathway controlling the timing of tissue and organ formation in an animal. To begin to understand the evolution of this pathway and the significance of the relationships among its components, we characterized 11 Caenorhabditis briggsae orthologs of C. elegans heterochronic genes. Using CRISPR/Cas9, we made a variety of alleles and found that several mutant phenotypes differ in significant ways from those of C. elegans. Although most mutant orthologs displayed defects in developmental timing, their phenotypes could differ in which stages were affected, the penetrance and expressivity of the phenotypes, or by having additional pleiotropies that were not obviously connected to developmental timing. However, when examining pairwise epistasis and synergistic relationships, we found those paralleled the known relationships between their C. elegans orthologs, suggesting that the arrangements of these genes in functional modules are conserved, but the modules’ relationships to each other and/or to their targets has drifted since the time of the species’ last common ancestor. Furthermore, our investigation has revealed a relationship between this pathway to other aspects of the animal's growth and development, including gonad development, which is relevant to both species.
Construction and analysis of the chromosome-level haplotype-resolved genomes of two Crassostrea oyster congeners: Crassostrea angulata and Crassostrea gigas
Authors: Qi Haigang , Cong Rihao , Wang Yanjun , Li Li , Zhang Guofan
Published: October 2023

Background

The Portuguese oyster Crassostrea angulata and the Pacific oyster C. gigas are two major Crassostrea species that are naturally distributed along the Northwest Pacific coast and possess great ecological and economic value. Here, we report the construction and comparative analysis of the chromosome-level haplotype-resolved genomes of the two oyster congeners.

Findings

Based on a trio-binning strategy, the PacBio high-fidelity and Illumina Hi-C reads of the offspring of the hybrid cross C. angulata (♂) × C. gigas (♀) were partitioned and independently assembled to construct two chromosome-level fully phased genomes. The assembly size (contig N50 size, BUSCO completeness) of the two genomes were 582.4 M (12.8 M, 99.1%) and 606.4 M (5.46 M, 98.9%) for C. angulata and C. gigas, respectively, ranking at the top of mollusk genomes with high contiguity and integrity. The general features of the two genomes were highly similar, and 15,475 highly conserved ortholog gene pairs shared identical gene structures and similar genomic locations. Highly similar sequences can be primarily identified in the coding regions, whereas most noncoding regions and introns of genes in the same ortholog group contain substantial small genomic and/or structural variations. Based on population resequencing analysis, a total of 2,756 species-specific single-nucleotide polymorphisms and 1,088 genes possibly under selection were identified.

Conclusions

This is the first report of trio-binned fully phased chromosome-level genomes in marine invertebrates. The study provides fundamental resources for the research on mollusk genetics, comparative genomics, and molecular evolution.
Distributed model predictive control of vehicle platoons under switching communication topologies
Authors: Chen Liang , Zhan Jingyuan , Zhang Liguo
Published: October 2023

This paper studies the control problem for vehicle platoons under switching communication topologies, where the Predecessor-Following (PF)-failure topology is allowed. Firstly, we design a local optimization problem for each vehicle by using the state information of itself and its neighbouring vehicles, and then present Algorithm 1 based on Distributed Model Predictive Control (DMPC). By constructing a common Lyapunov function defined by the joint neighbourhood set, we derive sufficient conditions with respect to the weight matrices in the open-loop optimization problem and the switching topologies for ensuring the stability of the closed-loop system under Algorithm 1. Furthermore, we propose Algorithm 2 by introducing novel constraints into the local optimization problem for each vehicle, which utilize shrinking historical position errors to cope with PF-link failures, such that the string stability of the vehicle platoon is ensured. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed DMPC algorithms for the vehicel platoon under switching communication topologies.
Artificial Intelligence and Infectious Disease Imaging
Authors: Chu Winston T , Reza Syed M S , Anibal James T , Landa Adam , Crozier Ian , Bağci Ulaş , Wood Bradford J , Solomon Jeffrey
Published: October 2023

The mass production of the graphics processing unit and the coronavirus disease 2019 (COVID-19) pandemic have provided the means and the motivation, respectively, for rapid developments in artificial intelligence (AI) and medical imaging techniques. This has led to new opportunities to improve patient care but also new challenges that must be overcome before these techniques are put into practice. In particular, early AI models reported high performances but failed to perform as well on new data. However, these mistakes motivated further innovation focused on developing models that were not only accurate but also stable and generalizable to new data. The recent developments in AI in response to the COVID-19 pandemic will reap future dividends by facilitating, expediting, and informing other medical AI applications and educating the broad academic audience on the topic. Furthermore, AI research on imaging animal models of infectious diseases offers a unique problem space that can fill in evidence gaps that exist in clinical infectious disease research. Here, we aim to provide a focused assessment of the AI techniques leveraged in the infectious disease imaging research space, highlight the unique challenges, and discuss burgeoning solutions.
Imaging-Selected Host Responses in the Context of Infections
Authors: Foss Catherine A , Renslo Adam R
Published: October 2023

Recently developed molecular imaging approaches can be used to visualize specific host responses and pathology in a quest to image infections where few microbe-specific tracers have been developed and in recognition that host responses contribute to morbidity and mortality in their own right. Here we highlight several recent examples of these imaging approaches adapted for imaging infections. The early successes and new avenues described here encompass diverse imaging modalities and leverage diverse aspects of the host response to infection—including inflammation, tissue injury and healing, and key nutrients during host-pathogen interactions. Clearly, these approaches merit further preclinical and clinical study as they are complementary and orthogonal to the pathogen-focused imaging modalities currently under investigation.
Space use patterns of two large carnivores: Puma (Puma concolor) and Maned Wolf (Chrysocyon brachyurus) in tropical agroecosystems
Authors: Pônzio Marcella do Carmo , Pasqualotto Nielson , Alberici Vinicius , Paolino Roberta Montanheiro , Rodrigues Thiago Ferreira , Chiarello Adriano G
Published: October 2023

Mammalian carnivores are often vulnerable to the conversion of natural habitat. Although some species might be frequent in anthropogenic areas, it is not entirely clear how they use modified landscapes, particularly in tropical agroecosystems. Here, we investigated how Puma (Puma concolor) and Maned Wolf (Chrysocyon brachyurus) used three disturbed areas in southeastern Brazil. We sampled 205 camera stations and estimated species occupancy (Ψ) and detection probabilities (p), interpreted as probability of use and frequency of use, respectively. Our models predicted that both species extensively used the study areas (model-averaged probability of use of 0.65 for pumas and 0.50 for maned wolves). Puma frequency of use was higher in stations further from human structures and areas of savanna. Maned Wolf frequency of use was lower in forest-dominated stations and in a more protected and forested study area. Puma probability of use was high in stations closer to watercourses, while Maned Wolf probability of use was higher in unpaved roads and stations farther from human structures. Our findings suggest that pumas and maned wolves may be able to adapt their use of space in agroecosystems featuring riparian corridors and unpaved roads. Nevertheless, our data also reveal possible impacts to carnivore populations in these systems, such as the degradation of riparian environments, road mortality, and human construction avoidance. Thus, some caution is warranted in considering highly modified environments as safe habitats for large carnivores, until further data on the density and vital rates of these species in agricultural-dominated areas have been quantified.