bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition to GPU-based reconstruction for clinical organ-targeted PET scanner
Authors: Komarov Borys , Maa-Hacquoil Henry , Poladyan Harutyun , Baldassi Brandon , Shahi Anirudh , Anashkin Edward , Bubon Oleksandr , Reznik Alla 
Published: February 2025

Abstract

Objective. This article explores a new graphics processing unit (GPU)-based techniques for efficient image reconstruction in organ-targeted positron emission tomography (PET) scanners with planar detectors. Approach. GPU-based reconstruction is applied to the Radialis low-dose organ-targeted PET technology, developed to overcome the issues of high exposure and limited spatial resolution inherent in traditional whole-body PET/CT (Computed Tomography) scans. The Radialis planar detector technology is based on four-side tileable sensor modules that can be seamlessly combined into a sensing area of the needed size, optimizing the axial field-of-view for specific organs, and maximizing geometric sensitivity. The article explores the transition from central processing unit-based maximum likelihood expectation maximization algorithms to a GPU-based counterpart, demonstrating a tenfold overall speedup in image reconstruction with a hundredfold improvement in iteration speed. Main results. Through standardized PET performance tests and clinical image analysis, this work demonstrates that GPU-based image reconstruction maintains diagnostic image quality while significantly reducing reconstruction times. The application of this technology, particularly in breast imaging using the Radialis low-dose positron emission mammography, significantly reduces exam times thus improving patient comfort and throughput in clinical settings. Significance. This study represents an important advancement in the clinical workflow of PET imaging, providing insights into optimizing reconstruction algorithms to effectively leverage the parallel processing capabilities of GPUs.
Drastic effects of N2 addition in the chemical composition of C2H2/Ar glow discharges
Authors: Tanarro Isabel , Peláez Ramón J , Herrero Víctor J 
Published: February 2025

Abstract
The effects of nitrogen on the physicochemical properties of cold acetylene plasmas have been experimentally studied in C2H2/Ar capacitive radio frequency (RF) discharges. Two discharges containing respectively 0.8% and 6.3% N2 in the initial gas mixture were investigated under conditions of incipient polymerization, using mass spectrometry, light scattering, and optical emission spectroscopy. During the initial transient, dust particles, small polyynes, and C2 radicals were found to form and decay in parallel with a steep drop in the C2H2 concentration and an increase in the concentration of hydrogen cyanide, which was more prominent for the 6.3% N2 mixture, and participated actively in the plasma chemistry. Over this time interval, relevant plasma parameters including the electron density and excitation temperature, the self-bias voltage, and the density of electronic excited states of various plasma species were found to undergo sharp variations. After this initial transient, lasting for about 20 s, a steady state was reached with stable plasma properties. Ion distributions were measured in the steady state, where no dust particles remained. The distributions of positive ions were dominated by species with an even number of carbon atoms, reflecting the prevailing polymerization mechanisms. The increase in the N2 concentration from 0.8% to 6.3% led to a decrease in the global cation signal and to a marked growth in the intensity of detected anions. The cation distributions did not change much, but in the anion distributions, the peaks corresponding to the masses of the C2n−1N− (n = 1–4) ions grew by orders of magnitude, in contrast with those of the adjacent C2n
H− peaks, which showed comparatively modest changes. These results could help identify anionic polymerization routes. Note that the two anion families mentioned correspond to the negative ions observed thus far in interstellar and circumstellar media.
Electron density measurements and calculations in a helium capacitively-coupled radio-frequency plasma
Authors: Bentz Brian Z , Hartmann Peter , Derzsi Aranka , Youngman Kevin , Donkó Zoltán 
Published: February 2025

Abstract
We report a comparison of inferred electron density (

n

e

) in a He capacitively-coupled plasma, deduced from laser-collision induced fluorescence measurements, with values computed using a hybrid simulation framework based on particle-in-cell/Monte Carlo collisions simulations and a fluid model for excited He atoms. The studies were carried out for gas pressures between 50 mTorr and 1000 mTorr and peak-to-peak radio-frequency (13.56 MHz) voltages between 150 V and 350 V, in a highly symmetric source equipped with plane-parallel electrodes. A good agreement is found between the experimental and modeling results for

n

e

except at the lowest operating voltages and gas pressures. The (effective) electron temperature (

T

e

) values derived by the two methods agree as well reasonably within the plasma bulk. The simulation results are used to compare the density distributions of He+ and various He excited levels and their major populating and de-populating channels at 100 mTorr and 1000 mTorr.
Dielectric elastomer actuator based mechanical counterpressure space suit cuff
Authors: Veloso Eugenio , Cohen Andy J , Wood Robert J 
Published: February 2025

Abstract
Mechanical counterpressure (MCP) space suits could offer advantages over current gas-pressurized suits in safety, mobility, and decreased suit complexity and volume. However, a passive MCP space suit design poses challenges with donning and doffing as it must be exceedingly tight, requiring 29.6 kPa of MCP. Equipping the suit with wearable active devices, such as an expanding cuff, is a potential solution to this issue. These devices could allow the suit to loosen and tighten to aid in donning and doffing and to conform to changes in body geometry during movement. Dielectric elastomer actuators (DEAs) are a promising candidate for the active device element of an MCP space suit design due to their compliance, high energy density, long lifetime, and high bandwidth. The high voltage required to drive DEAs can be reduced by subdividing the dielectric layer of the DEA to create DEA multilayers (DEAMs). This work presents a DEAM-based MCP space suit cuff, a fundamental component of a full suit concept, that applies passive pressure through prestretch and loosens upon actuation for donning, doffing, and during movement. The cuff is fabricated using a batch-spray and stamp technique, and it consists of 24 active layers, each 200 µm in thickness, giving the cuff a total thickness of 6 mm including inactive encapsulation layers. The final cuff design achieves an MCP of 19.52 kPa, a maximum pressure relief of 5.42 kPa, and a response time of 0.7 s. The proposed design can achieve a counterpressure of 29 kPa with a prestretch factor of 2.42. These results demonstrate the capabilities of DEAM-based wearable devices, introducing novel actuation functionality to wearable technology.
Simultaneous determination of two path weak-values with time-dependent phase manipulation in neutron interferometry
Authors: Masiello Ismaele V , Dvorak Andreas , Lemmel Hartmut , Danner Armin , Hasegawa Yuji 
Published: February 2025

Abstract
Weak values are found to play an important role in the study of many fundamental concepts of quantum mechanics. We present a method to simultaneously extract the imaginary part of the weak value of both path operators in a two-path Mach–Zehnder neutron interferometer using time-dependent phases. The measurement does not require spin manipulation, e.g. spin rotation and analysis. The methodology can be extended to an arbitrary number of paths and the working principles are transferable to any other kind of interferometer experiment in which alike time-dependent phases are feasible. Furthermore, we demonstrate a relation among components of path weak values relative to different post-selected states. This relation allows the additional extraction of the real part of both path weak values using the same setup, assuming the relative phase between the states after the different post-selections to be known.
Core Mass Function in View of Fractal and Turbulent Filaments and Fibers
Authors: Liu 刘 Xunchuan 训川 , Liu Tie , Mai Xiaofeng , Cheng Yu , Jiao Sihan , Jiao Wenyu , Liu Hongli , Zhang Siju 
Published: February 2025

Abstract
We propose that the core mass function (CMF) can be driven by filament fragmentation. To model a star-forming system of filaments and fibers, we develop a fractal and turbulent tree with a fractal dimension of 2 and a Larson’s law exponent (β) of 0.5. The fragmentation driven by convergent flows along the splines of the fractal tree yields a Kroupa-IMF-like CMF that can be divided into three power-law segments with exponents α = −0.5, −1.5, and −2, respectively. The turnover masses of the derived CMF are approximately four times those of the Kroupa IMF, corresponding to a star formation efficiency of 0.25. Adopting β = 1/3, which leads to fractional Brownian motion along the filament, may explain a steeper CMF at the high-mass end, with α = −3.33 close to that of the Salpeter IMF. We suggest that the fibers of the tree are basic building blocks of star formation, with similar properties across different clouds, establishing a common density threshold for star formation and leading to a universal CMF.
Jets are the Most Robust Observable Ingredient of Common Envelope Evolution
Authors: Soker Noam 
Published: February 2025

Abstract
I examine images of 50 planetary nebulae (PNe) with observable post-common envelope evolution (CEE) binary central stars and find that jets are about 40% more common than dense equatorial outflows. Because, in some cases, energetic jets can compress an equatorial outflow and because fast jets might disperse early in the PN evolution and avoid detection, the CEE process is likelier to launch jets than to eject a dense equatorial outflow by a larger factor than 1.4. In most cases, the companion, mainly a main sequence star, launches the jets as it accretes mass from the envelope of the giant star. By CEE jets, I also refer to jets launched shortly before the onset of the CEE, likely a grazing envelope evolution phase, and shortly after the CEE. The jets and the accretion of mass by the companion before, during, and after the CEE affect envelope mass removal and the final orbital separation. Most numerical simulations of the CEE ignore jets, and those that include jets omit other processes. Despite the considerable progress in the last decade with tens of hydrodynamical simulations of the CEE, we are still far from correctly simulating the CEE. Including jets in simulations of the CEE requires heavy computer resources, but it must be the next step.
Assessing air pollution exposure disparities in disadvantaged communities of Greater Boston: a new cumulative environmental justice score system
Authors: Do Khanh , Zhang Yang , Ma Siqi , Tong Daniel 
Published: February 2025

Abstract
Disadvantaged communities in the U.S. experience higher levels of air pollution, leading to increased environmental justice (EJ) challenges. In this work, we combine socioeconomic metrics with spatially interpolated fine particulate matter and ozone concentrations from fifty-nine low-cost sensors and nine reference monitors to investigate inequality in air pollution exposure among different population groups in Greater Boston. The results indicate that the disadvantaged groups are exposed to higher levels of air pollution. Air pollution is concentrated in the center of Boston, Cambridge, Chelsea, and Everett, corresponding to high population density and anthropogenic activities. We further assess the environmental equality by reconstructing the EJ map for Massachusetts using median household income, percentage of minority, and percentage of limited English speaking as indicators. The EJ blocks are clustered in large cities across Massachusetts. Many communities in Greater Boston are classified as EJ communities due to the high percentage of minorities. Chelsea and Everett face more severe EJ issues, with most of their communities exceeding multiple EJ indicators. Additionally, we introduce and demonstrate a new method for determining EJ communities by utilizing the multi-criterion framework to calculate the cumulative EJ score for every census block, integrating air quality with socioeconomic indicators, and each indicator can be viewed as a policy action. Chelsea, Everett, and Lynn consistently exhibit the highest EJ scores with no improvements over the years. The EJ score system provides the time evolution to assist authorities and the residents in tracking the progress in improving the EJ scores of their communities. The method indicates the strength of the efforts needed to maintain or improve the EJ scores for achieving better EJ in the communities, allowing authorities to take immediate actions to improve the environmental well-being of vulnerable communities.
A Gigahertz configurable silicon photonic integrated circuit nonlinear interferometer
Authors: Frazer Jonathan , Ono Takafumi , Matthews Jonathan C F 
Published: February 2025

Abstract
Low loss and high-speed processing of photons is important to photonic quantum information technologies. The speed with which quantum light generation can be modulated impacts the clock rate of photonic quantum computers, the data rate of quantum communication and applications of quantum enhanced radio-frequency sensors. Here we use lossy carrier depletion modulators in a silicon waveguide nonlinear interferometer to modulate photon pair generation probability at 1 gigahertz (GHz) without exposing the generated photons to the phase dependent parasitic loss of the modulators. The super sensitivity of nonlinear interferometers reduces power consumption compared to modulating the driving laser. This can be used for high-speed programmable nonlinearity in waveguide networks for quantum technologies and for optical quantum sensors.
IFD-BiC: a class-incremental continual learning method for diesel engine fault diagnosis
Authors: Chen Tianyou , Xiang Yang , Wang Xihan 
Published: February 2025

Abstract
In recent years, deep learning-based fault diagnosis methods for diesel engines have been developed assuming that a comprehensive dataset is available for one-time learning. However, in reality, it is impractical to obtain a complete dataset all at once. Instead, new data is gradually acquired over time. To address this issue, this paper proposes an incremental fault diagnosis method with bias correction (IFD-BiC). When receiving incremental fault data, the IFD-BiC model incorporates new classifier nodes and updates network parameters using a combination of distillation loss and cross-entropy. During the update process, old samples saved in the exemplar set are replayed, and a bias correction layer is used to correct the prediction bias caused by the imbalance between new and old samples. This enables the model to learn new fault tasks without experiencing catastrophic forgetting. To ensure the applicability of the method to various operating conditions of diesel engines, cyclic angular vibration with consistent length at different speeds is used as the model input. Through experimental validation across a pair of distinct diesel engine models, the proposed method achieves highly accurate fault diagnosis on stream format training data. Moreover, an evaluation against leading incremental learning techniques affirms the proposed method’s advantage.
A fault diagnosis model for insulator instance segmentation in transmission lines based on ELD-YOLOv8
Authors: Ren Yiming , Du Dongsheng 
Published: February 2025

Abstract
A novel ELD-YOLOv8n transmission line insulator instance segmentation fault diagnosis model is proposed to accurately and meticulously segment every fault of the transmission line insulator. Firstly, an innovative and efficient lightweight downsampling module (ELD) was proposed, Efficient-Lightweight downsampling, This module is used to replace the standard downsampling unit in the model, which not only reduces the number of model parameters, but also enhances the feature extraction ability of the model. Then, a lightweight CARAFE module was used to replace the upsampling of the model, optimizing the upsampling process and reducing the number of parameters. Finally, CGAFusion is used to fuse the features extracted from the backbone network with the head features, effectively compensating for the information loss caused by the convolution process. The experimental results show that the improved model proposed in this study achieved an mAP@50 of 86.2%. The effectiveness of the improvement and significant instance segmentation fault detection capability have been demonstrated through ablation experiments. This study provides a new technical path for fault diagnosis of insulator instance segmentation in transmission lines.
A generative modeling approach to reconstructing 21 cm tomographic data
Authors: Sabti Nashwan , Purandhar Reddy Sudha Ram , Muñoz Julian B , Mishra-Sharma Siddharth , Youn Taewook 
Published: February 2025

Abstract
Analyses of the cosmic 21 cm signal are hampered by astrophysical foregrounds that are far stronger than the signal itself. These foregrounds, typically confined to a wedge-shaped region in Fourier space, often necessitate the removal of a vast majority of modes, thereby degrading the quality of the data anisotropically. To address this challenge, we introduce a novel deep generative model based on stochastic interpolants to reconstruct the 21 cm data lost to wedge filtering. Our method leverages the non-Gaussian nature of the 21 cm signal to effectively map wedge-filtered 3D lightcones to samples from the conditional distribution of wedge-recovered lightcones. We demonstrate how our method is able to restore spatial information effectively, considering both varying cosmological initial conditions and astrophysics. Furthermore, we discuss a number of future avenues where this approach could be applied in analyses of the 21 cm signal, potentially offering new opportunities to improve our understanding of the Universe during the epochs of cosmic dawn and reionization.

Code, pre-trained models, and scripts for making plots in this paper can be found here.
To the geometry of spaces of plurisubharmonic functions on a Kähler manifold
Authors: Lempert László 
Published: February 2025

Consider a compact Kähler manifold

(
X
,
ω
)

(X,\omega )

and the space

E

(
X
,
ω
)

=

E

\mathcal {E}(X,\omega )\!= \mathcal {E}

of

ω
\omega

–plurisubharmonic functions of full Monge–Ampère mass on it. We introduce a quantity

ρ
[
u
,
v
]

\rho [u,v]

to measure the distance between

u
,
v
∈

E

u, v\in \mathcal {E}

;

ρ
[
u
,
v
]

\rho [u,v]

is not a number but rather a decreasing function on a certain interval

(
0
,
V
)
⊂

R

(0,V)\subset \mathbb {R}

. We explore properties of

ρ
[
u
,
v
]

\rho [u,v]

, and using them we study Lagrangians and associated energy spaces of

ω
\omega

–plurisubharmonic functions. Many results here generalize Darvas’s findings about his metrics

d
χ

d_\chi

.
How Regional Organizations Sustain Authoritarian Rule
Authors: Debre Maria J 
Published: February 2025

Abstract
Authoritarian regional organizations (ROs) have experienced a remarkable rise in numbers and importance. Autocracies across all world regions have joined organizations such as the Shanghai Cooperation Organization (SCO), the Gulf Cooperation Council (GCC), and the Bolivarian Alliance for the Peoples of Our America (ALBA). Why do autocracies institutionalize cooperation and join ROs, thereby bearing possible sovereignty costs? Do authoritarian ROs differ from their democratic counterparts in terms of activities and design? And what are the domestic effects from membership for authoritarian rule? How Regional Organizations Sustain Authoritarian Rule details how ROs help autocratic regimes secure their hold on power. The book shows how autocratic incumbent regimes sort into dictator clubs that help to successfully defend against domestic and international challenges during moments of political instability. This happens via distinct causal chains. Dictator clubs redistribute resources toward authoritarian elites that raise the cost of challenging behavior for the opposition, they regulate appropriate behavior among fellow members to prevent regional interference on the side of dissenting actors, and they protect regimes in case of international pressure and thereby lower the cost of employing repressive tactics. Combining statistical survival analysis and case-based evidence from the Middle East, (Eur)Asia, Sub-Saharan Africa, and Latin America, the book shows that ROs have had a helping hand in defending autocratic regimes from pro-democratic protestors, in co-opting political elites, in legitimizing flawed elections, and in shielding against the fallout from international sanctions. The book thereby shows how ROs are responsible for reinforcing authoritarian rule across the globe.
Patterns of Authoritarian Membership in Regional Organizations
Authors: Debre Maria J 
Published: February 2025

Abstract
This chapter introduces the data used for quantitative analysis and presents descriptive statistics on the development of autocratic regional organizations across time and regions. It provides answers concerning three main areas: the geographical distribution of dictator clubs, their historical development, and their institutional design, paying particular attention to their autocratic density, homogeneity, and authority. It shows that dictator clubs are a ubiquitous phenomenon even after the wave of democratization in the 1990s, and that dictator clubs do not necessarily differ profoundly from their democratic counterparts in terms of institutional design. The chapter concludes with an update on the regime survival and regime breakdown data used in the book.
The Effects of Membership in Dictator Clubs on Regime Survival
Authors: Debre Maria J 
Published: February 2025

Abstract
This chapter engages in survival analysis to study the extent to which membership in dictator clubs prolongs the time in office for autocratic incumbents. It shows that across time and space, membership in dictator clubs with higher autocratic density significantly reduced the probability of experiencing democratic breakdown, but it does not seem to protect from authoritarian elite challenges such as coups. In contrast, other international explanations including close relationships with authoritarian powers, authority and decision-making rules of institutions, and diffusion of authoritarian practices do not systematically explain authoritarian survival. The findings presented in this chapter thereby speak to the importance of institutional theory in the international study of authoritarian resilience.
How Dictator Clubs Empower Autocratic Incumbents
Authors: Debre Maria J 
Published: February 2025

Abstract
Chapter 5 engages in a most-different system design to show how dictator clubs help to prevent democratization during moments of political crisis focusing on three diverse regional organizations (ROs) from different world regions. The chapter analyzes democratic challenges in Bahrain, Zimbabwe, and China, ranging from public protest during the Arab Spring to election loss of revolutionary parties in Southern Africa and ethnic dissident by Uyghur minorities in Eurasia. The chapter demonstrates that material and immaterial resources provided by the Gulf Cooperation Council (GCC), the Southern African Development Community (SADC), and the Shanghai Cooperation Organization (SCO) helped to tip the scale in favor of autocratic incumbents during politically contentious moments.