bluuebunny/crossref_metadata_2025 huggingface dataset:
The gamma-variate in contrast-enhanced imaging: a unified view and method from computed to electrical impedance tomography
Authors: Silva Diogo F , Leonhardt Steffen
Published: April 2024

Objective. Modern medical imaging plays a vital role in clinical practice, enabling non-invasive visualization of anatomical structures. Dynamic contrast enhancement (DCE) imaging is a technique that uses contrast agents to visualize blood flow dynamics in a time-resolved manner. It can be applied to different modalities, such as computed tomography (CT) and electrical impedance tomography (EIT). This study aims to develop a common theoretical and practical hemodynamic extraction basis for DCE modelling across modalities, based on the gamma-variate function. Approach. The study introduces a framework to generate time-intensity curves for multiple DCE imaging modalities from user-defined hemodynamic parameters. Thus, extensive datasets were simulated for both DCE-CT and EIT, representing different hemodynamic scenarios. Additionally, gamma-variate extensions to account for several physiological effects were detailed in a modality-agnostic manner, and three corresponding fitting strategies, namely nonlinear, linear, and a novel hybrid approach, were implemented and compared on the basis of accuracy of parameter estimation, first pass reconstruction, speed of computation, and failure rate. Main results. As a result, we found the linear method to be the most modality-dependent, exhibiting the greatest bias, variance and failure rates, although remaining the fastest alternative. The hybrid method at least matches the state-of-the-art nonlinear method’s accuracy, while improving its robustness and speed by 10 times. Significance. Our research suggests that the hybrid method may bring noteworthy accuracy and efficiency improvements in handling the high-dimensionality of DCE imaging in general, being a step towards real-time processing. Moreover, our generative model presents a potential asset to produce benchmarking and data augmentation datasets across modalities.
Active stiffness tuning of lattice metamaterials
Authors: Mostofizadeh Parham , Dorey Robert A , Mohagheghian Iman
Published: April 2024

In this paper, surface conductive heating was utilized to actively control the stiffness of lattice metamaterials manufactured employing multi-material 3D printing. To create an electrical surface conduction, additively manufactured samples in single and dual material configurations were dip coated in a solution of carbon black in water. Electro-thermo-mechanical tests conducted successfully demonstrated that the low-cost conductive coating can be used to actively alter the stiffness of the structure through surface joule heating. The process was found to result in repeatable and reproduceable stiffness tuning. Stiffness reductions of 56% and 94% were demonstrated for single and dual material configurations under the same electrical loading. The proposed methodology can be implemented to actively control the properties of polymeric lattice materials/structures where the change in the composition of polymers (introduce bulk electrical conductivity) is difficult and can have a wide range of applications in soft robotics, shape-changing, and deployable structures.
Harmonic generation in a terawatt x-ray free-electron laser
Authors: Freund H P , O’Shea P G
Published: April 2024

Terawatt x-ray free-electron lasers (XFELs) represent the frontier in further development of x-ray sources and require high current densities with strong transverse focusing. In this paper, we investigate the implications/potentialities of TW XFELs on the generation of harmonics at still shorter wavelengths and higher photon energies. The simulations indicate that significant power levels are possible at high harmonics of the XFEL resonance and that these XFELs can be an important coherent source of hard x-rays through the gamma ray spectrum. For this purpose, we use the MINERVA simulation code which self-consistently includes harmonic generation. Both helical and planar undulators are discussed in which the fundamental is at 1.5 Å and study the associated harmonic generation. While tapered undulators are needed to reach TW powers at the fundamental, the taper does not enhance the harmonics because the taper must start before saturation of the fundamental, while the harmonics saturate before this point is reached. Nevertheless, the harmonics reach substantial powers. Simulations indicate that, for the parameters under consideration, peak powers of the order of 180 MW are possible at the fifth harmonic with a photon energy of about 41 keV and still high harmonics may also be generated at substantial powers. Such high harmonic powers are certain to enable a host of enhanced applications.
Multiple rogue wave solutions of the (1+1)-dimensional Benjamin-Ono equation
Authors: Ma Wenbo , Sudao Bilige , Shao Hangbing
Published: April 2024

In this paper, by means of symbolic computation, we studied the multiple rogue wave (multi-RW) solutions of the (1+1)-dimensional Benjamin-Ono (BO) equation, which is used to describe one-dimensional deep water internal waves in mathematics. In order to achieve this goal, we used the bilinear neural network method to construct the superposition formulas of n-RW based on the bilinear form. Here we only showed 1-RW, 3-RW, and 6-RW solutions. The influence of the parameters in the solution expression upon the characteristics related to RW also was discussed. Then, the dynamics characteristics of the multi-RW solutions were analyzed by drawing the three-dimensional plot, contour plot, and density plot. We observed that m-RW consisted of m independent 1-RW. This interesting phenomenon helped us to better reveal the evolution mechanism of the (1+1)-dimensional BO equation.
First-principles exploration of N- and Pd-doped graphene as CO and NO2 gas sensor for operation status evaluation in AIS
Authors: Wu Hailong , Zhong Shan , He Dan , Cui Hao
Published: April 2024

To evaluate the operation status of air insulated switchgears (AIS), this work purposes N- and Pd- embedded graphene (N- and Pd-graphene) as potential gas sensors upon two typical faults gases (CO and NO2) from the first-principles simulations. It is found that the N and Pd atoms can be stably trapped on the C-vacancy of the C-defected graphene with the formation energy of −12.17 and −5.12 eV, respectively. N-graphene behaves physisorption towards CO and NO2 molecules while Pd-graphene behaves chemisorption instead. The resistance-type and work function (WF)-based sensing mechanisms of N- and Pd-graphene upon such two gas species are illustrated and uncovered by analyzing their deformations of electronic property and WF in the gas adsorption systems, which reveals the potential of Pd-graphene as a resistive CO and NO2 sensor, N-graphene as a resistive NO2 sensor, as well as the N- and Pd-graphene as WF-based gas sensor for NO2 detection. This work highlights the comparison of adsorption and sensing performances between N- and Pd-graphene upon two typical gas sensors in AIS, which would be meaningful to explore novel graphene-based sensing materials facilitating their investigations and applications in the power system.
Review of Hubble tension solutions with new SH0ES and SPT-3G data
Authors: Khalife Ali Rida , Zanjani Maryam Bahrami , Galli Silvia , Günther Sven , Lesgourgues Julien , Benabed Karim
Published: April 2024

We present an updated analysis of eleven cosmological models that may help reduce the Hubble tension, which now reaches the 6σ level when considering the latest SH0ES measurement versus recent CMB and BAO data, assuming ΛCDM.
Specifically, we look at five classical extensions of ΛCDM (with massive neutrinos, spatial curvature, free-streaming or self-interacting relativistic relics, or dynamical dark energy) and six elaborate models featuring either a time-varying electron mass, early dark energy or some non-trivial interactions in the neutrino sector triggered by a light Majoron. We improve over previous works in several ways. We include the latest data from the South Pole Telescope as well as the most recent measurement of the Hubble rate by the SH0ES collaboration. We treat the summed neutrino mass as a free parameter in most of our models, which reveals interesting degeneracies and constraints. We define additional metrics to assess the potential of a model to reduce or even solve the Hubble tension. We validate an emulator that uses active learning to train itself during each parameter inference run for any arbitrary model. We find that the time-varying electron mass and the Majoron models are now ruled out at more than 3σ. Models with a time-varying electron mass and spatial curvature or with early dark energy reduce the tension to 1.0-2.9σ. Nevertheless, none of the models considered in this work is favored with enough statistical significance to become the next concordance model of Cosmology.
Constraints on Lorentz invariance violation from the LHAASO observation of GRB 221009A
Authors: Yang Yu-Ming , Bi Xiao-Jun , Yin Peng-Fei
Published: April 2024

In some quantum gravity (QG) theories, Lorentz symmetry may be broken above the Planck scale. The Lorentz invariance violation (LIV) may induce observable effects at low energies and be detected at high energy astrophysical measurements.
The Large High Altitude Air Shower Observatory (LHAASO) has detected the onset, rise, and decay phases of the afterglow of GRB 221009A, covering a wide energy range of photons approximately from 0.2 to 13 TeV. This observation provides an excellent opportunity to study the Lorentz invariance violation effect. In this study, we simultaneously utilize the data from the KM2A and WCDA detectors of LHAASO, and apply two event by event methods, namely the pair view method and maximum likelihood method, to investigate LIV. We obtain stringent constraints on the QG energy scale. For instance, through the maximum likelihood method, we determine the 95% confidence level lower limits to be E
QG,1 > 14.7 (6.5) × 1019 GeV for the subluminal (superluminal) scenario of n = 1, and E
QG,2 > 12.0 (7.2) × 1011 GeV for the subluminal (superluminal) scenario of n = 2. We find that the rapid rise and slow decay behaviors of the afterglow can impose strong constraints on the subluminal scenario, while the constraints are weaker for the superluminal scenario.
In-flight Energy Calibration of the GECAM Gamma-ray Detectors
Authors: Qiao Rui , Guo Dong-Ya , Peng Wen-Xi , Zhang Yan-Qiu , Xiao Shuo , Xiong Shao-Lin , Zheng Chao , Li Chao-Yang , Liu Jia-Cong , Xue Wang-Chen , He Jian-Jian , An Zheng-Hua , Zhang Da-Li , Li Xin-Qiao , Song Li-Ming , Zheng Shi-Jie , Gong Ke , Liu Ya-Qing , Song Xin-Ying , Zhao Xiao-Yun , Wen Xiang-Yang , Xu Yan-Bing , Ma Xiang , Li Xiao-Bo , Wang Ping , Huang Yue , Cai Ce , Yi Qi-Bin , Zhao Yi , Wang Chen-Wei
Published: April 2024

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission is designed to monitor the Gamma-Ray Bursts (GRBs) associated with gravitational waves and other high-energy transient sources. The mission consists of two microsatellites which are planned to operate at the opposite sides of the Earth. Each GECAM satellite could detect and localize GRBs in about 8 keV–5 MeV with its 25 Gamma-Ray Detectors (GRDs). In this work, we report the in-flight energy calibration of GRDs using the characteristic gamma-ray lines in the background spectra, and show their performance evolution during the commissioning phase. Besides, a preliminary cross-calibration of energy response with Fermi GBM data is also presented, validating the energy response of GRDs.
An SSVEP-based BCI with 112 targets using frequency spatial multiplexing
Authors: Liu Yaru , Dai Wei , Liu Yadong , Hu Dewen , Yang Banghua , Zhou Zongtan
Published: April 2024

Objective. Brain–computer interface (BCI) systems with large directly accessible instruction sets are one of the difficulties in BCI research. Research to achieve high target resolution (

⩾

100) has not yet entered a rapid development stage, which contradicts the application requirements. Steady-state visual evoked potential (SSVEP) based BCIs have an advantage in terms of the number of targets, but the competitive mechanism between the target stimulus and its neighboring stimuli is a key challenge that prevents the target resolution from being improved significantly. Approach. In this paper, we reverse the competitive mechanism and propose a frequency spatial multiplexing method to produce more targets with limited frequencies. In the proposed paradigm, we replicated each flicker stimulus as a 2 × 2 matrix and arrange the matrices of all frequencies in a tiled fashion to form the interaction interface. With different arrangements, we designed and tested three example paradigms with different layouts. Further we designed a graph neural network that distinguishes between targets of the same frequency by recognizing the different electroencephalography (EEG) response distribution patterns evoked by each target and its neighboring targets. Main results. Extensive experiment studies employing eleven subjects have been performed to verify the validity of the proposed method. The average classification accuracies in the offline validation experiments for the three paradigms are 89.16%, 91.38%, and 87.90%, with information transfer rates (ITR) of 51.66, 53.96, and 50.55 bits/min, respectively. Significance. This study utilized the positional relationship between stimuli and did not circumvent the competing response problem. Therefore, other state-of-the-art methods focusing on enhancing the efficiency of SSVEP detection can be used as a basis for the present method to achieve very promising improvements.
Climate change critically affects the status of the land-system change planetary boundary
Authors: Tobian Arne , Gerten Dieter , Fetzer Ingo , Schaphoff Sibyll , Andersen Lauren Seaby , Cornell Sarah , Rockström Johan
Published: April 2024

The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten phase 6 of the Coupled Model Intercomparison Project models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth’s major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (>450 ppm) leads to critical transgression of the latter, with greater severity the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today’s boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the planetary boundaries framework.
Optimal superdense coding capacity in the non-Markovian regime
Authors: Aiache Y , Al-Kuwari S , El Anouz K , El Allati A
Published: April 2024

Superdense coding (SDC) is a significant technique widely used in quantum information processing. Indeed, it consists of sending two bits of classical information using a single qubit, leading to faster and more efficient quantum communication. In this paper, we propose a model to evaluate the effect of backflow information in a SDC protocol through a non-Markovian dynamics. The model considers a qubit interacting with a structured Markovian environment. In order to generate a non-Markovian dynamic, an auxiliary qubit contacts a Markovian reservoir in such a way that the non-Markovian regime can be induced. By varying the coupling strength between the central qubit and the auxiliary qubit, the two dynamical regimes can be switched interchangeably. An enhancement in non-Markovian effects corresponds to an increase in this coupling strength. Furthermore, we conduct an examination of various parameters, namely temperature weight, and decoherence parameters in order to explore the behaviors of SDC, quantum fisher information (QFI), and local quantum uncertainty using an exact calculation. The obtained results show a significant relationship between non-classical correlations and QFI since they behave similarly, allowing them to detect what is beyond entanglement. In addition, the presence of non-classical correlations enables us to detect the optimal SDC capacity in a non-Markovian regime.
Polar duality and the reconstruction of quantum covariance matrices from partial data
Authors: de Gosson Maurice
Published: April 2024

We address the problem of the reconstruction of quantum covariance matrices using the notion of Lagrangian and symplectic polar duality introduced in previous work. We apply our constructions to Gaussian quantum states which leads to a non-trivial generalization of Pauli’s reconstruction problem and we state a simple tomographic characterization of such states.
Pressure of Coulomb systems with volume-dependent long-range potentials
Authors: Onegin A S , Demyanov G S , Levashov P R
Published: April 2024

In this work, we consider the pressure of Coulomb systems, in which particles interact via a volume-dependent potential (in particular, the Ewald potential and its angular-averaged version (Demyanov and Levashov 2022 J. Phys. A: Math. Theor.
55 385202)). We confirm that the expression for the virial pressure should be corrected in this case. We show that the corrected virial pressure coincides with the formula obtained by differentiation of free energy if the potential energy is a homogeneous function of particle coordinates and a cell length. As a consequence, we find out that the expression for the pressure in the recent paper by Liang et al (2022 J. Chem. Phys.
157 144102) is incorrect.
A hybrid quantum ensemble learning model for malicious code detection
Authors: Xiong Qibing , Ding Xiaodong , Fei Yangyang , Zhou Xin , Du Qiming , Feng Congcong , Shan Zheng
Published: April 2024

Quantum computing as a new computing model with parallel computing capability and high information carrying capacity, has attracted a lot of attention from researchers. Ensemble learning is an effective strategy often used in machine learning to improve the performance of weak classifiers. Currently, the classification performance of quantum classifiers is not satisfactory enough due to factors such as the depth of quantum circuit, quantum noise, and quantum coding method, etc. For this reason, this paper combined the ensemble learning idea and quantum classifiers to design a novel hybrid quantum machine learning model. Firstly, we run the Stacking method in classical machine learning to realize the dimensionality reduction of high-latitude data while ensuring the validity of data features. Secondly, we used the Bagging method and Bayesian hyperparameter optimization method applied to quantum support vector machine (QSVM), quantum K nearest neighbors (QKNN), variational quantum classifier (VQC). Thirdly, the voting method is used to ensemble the predict results of QSVM, QKNN, VQC as the final result. We applied the hybrid quantum ensemble machine learning model to malicious code detection. The experimental results show that the classification precision (accuracy, F1-score) of this model has been improved to 98.9% (94.5%, 94.24%). Combined with the acceleration of quantum computing and the higher precision rate, it can effectively deal with the growing trend of malicious codes, which is of great significance to cyberspace security.
Polynomial preserving recovery for the finite volume element methods under simplex meshes
Authors: Li Yonghai , Yang Peng , Zhang Zhimin
Published: April 2024

The recovered gradient, using the polynomial preserving recovery (PPR), is constructed for the finite volume element method (FVEM) under simplex meshes. Regarding the main results of this paper, there are two aspects. Firstly, we investigate the supercloseness property of the FVEM, specifically examining the quadratic FVEM under tetrahedral meshes. Secondly, we present several guidelines for selecting computing nodes such that the least-squares fitting procedure of the PPR admits a unique solution. Numerical experiments demonstrate that the recovered gradient by the PPR exhibits superconvergence.
A note on almalgamated free products
Authors: Li Qihui , Hadwin Don , Shen Junhao
Published: April 2024

We prove a general result concerning properties preserved under certain amalgamated free products.
On Pólya’s random walk constants
Authors: Gaunt Robert , Nadarajah Saralees , Pogány Tibor
Published: April 2024

A celebrated result in probability theory is that a simple symmetric random walk on the

d
d

-dimensional lattice

Z

d

\mathbb {Z}^d

is recurrent for

d
=
1
,
2

d=1,2

and transient for

d
≥
3

d\geq 3

. In this note, we derive a closed-form expression, in terms of the Lauricella function

F
C

F_C

, for the return probability for all

d
≥
3

d\geq 3

. Previously, a closed-form formula had only been available for

d
=
3

d=3

.
Strichartz type estimates for solutions to the Schrödinger equation
Authors: Chen Jie
Published: April 2024

In this article, we show the necessary and sufficient conditions for the inequality
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar u double-vertical-bar Subscript upper L Sub Subscript t Sub Superscript q Subscript upper L Sub Subscript x Sub Superscript r Subscript Baseline less-than-or-equivalent-to double-vertical-bar u double-vertical-bar Subscript upper X Sub Superscript s comma b Subscript Baseline comma">

‖
u

‖

L
t
q

L
x
r

≲
‖
u

‖

X

s
,
b

,

\begin{equation*} \|u\|_{L_t^qL_x^r}\lesssim \|u\|_{X^{s,b}}, \end{equation*}

where
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar u double-vertical-bar Subscript upper X Sub Superscript s comma b Baseline colon-equal double-vertical-bar ModifyingAbove u With caret left-parenthesis tau comma xi right-parenthesis mathematical left-angle xi mathematical right-angle Superscript s Baseline mathematical left-angle tau plus StartAbsoluteValue xi EndAbsoluteValue squared mathematical right-angle Superscript b Baseline double-vertical-bar Subscript upper L Sub Subscript tau comma xi Sub Superscript 2">

‖
u

‖

X

s
,
b

≔
‖

u
^

(
τ
,
ξ
)
⟨
ξ

⟩
s

⟨
τ
+

|

ξ

|

2

⟩
b

‖

L

τ
,
ξ

2

\|u\|_{X^{s,b}}≔\|\hat {u}(\tau ,\xi )\langle \xi \rangle ^s\langle \tau +|\xi |^2\rangle ^b \|_{L_{\tau ,\xi }^2}

. These estimates are also referred to as Strichartz estimates related to Schrödinger equation. We also give a new proof of the maximal function estimates for solutions to Schrödinger and Airy equations.
Effective approximation to complex algebraic numbers by algebraic numbers of bounded degree
Authors: Bajpai Prajeet , Bugeaud Yann
Published: April 2024

We establish the first effective improvements on the Liouville inequality for approximation to complex non-real algebraic numbers by complex algebraic numbers of degree at most

4
4

.
Confounder-dependent Bayesian mixture model: Characterizing heterogeneity of causal effects in air pollution epidemiology
Authors: Zorzetto Dafne , Bargagli-Stoffi Falco J , Canale Antonio , Dominici. Francesca
Published: April 2024

Several epidemiological studies have provided evidence that long-term exposure to fine particulate matter (pm2.5) increases mortality rate. Furthermore, some population characteristics (e.g., age, race, and socioeconomic status) might play a crucial role in understanding vulnerability to air pollution. To inform policy, it is necessary to identify groups of the population that are more or less vulnerable to air pollution. In causal inference literature, the group average treatment effect (GATE) is a distinctive facet of the conditional average treatment effect. This widely employed metric serves to characterize the heterogeneity of a treatment effect based on some population characteristics. In this paper, we introduce a novel Confounder-Dependent Bayesian Mixture Model (CDBMM) to characterize causal effect heterogeneity. More specifically, our method leverages the flexibility of the dependent Dirichlet process to model the distribution of the potential outcomes conditionally to the covariates and the treatment levels, thus enabling us to: (i) identify heterogeneous and mutually exclusive population groups defined by similar GATEs in a data-driven way, and (ii) estimate and characterize the causal effects within each of the identified groups. Through simulations, we demonstrate the effectiveness of our method in uncovering key insights about treatment effects heterogeneity. We apply our method to claims data from Medicare enrollees in Texas. We found six mutually exclusive groups where the causal effects of pm2.5 on mortality rate are heterogeneous.
A semiparametric Gaussian mixture model for chest CT-based 3D blood vessel reconstruction
Authors: Zeng Qianhan , Zhou Jing , Ji Ying , Wang Hansheng
Published: April 2024

Computed tomography (CT) has been a powerful diagnostic tool since its emergence in the 1970s. Using CT data, 3D structures of human internal organs and tissues, such as blood vessels, can be reconstructed using professional software. This 3D reconstruction is crucial for surgical operations and can serve as a vivid medical teaching example. However, traditional 3D reconstruction heavily relies on manual operations, which are time-consuming, subjective, and require substantial experience. To address this problem, we develop a novel semiparametric Gaussian mixture model tailored for the 3D reconstruction of blood vessels. This model extends the classical Gaussian mixture model by enabling nonparametric variations in the component-wise parameters of interest according to voxel positions. We develop a kernel-based expectation–maximization algorithm for estimating the model parameters, accompanied by a supporting asymptotic theory. Furthermore, we propose a novel regression method for optimal bandwidth selection. Compared to the conventional cross-validation-based (CV) method, the regression method outperforms the CV method in terms of computational and statistical efficiency. In application, this methodology facilitates the fully automated reconstruction of 3D blood vessel structures with remarkable accuracy.
Nitrogen-fixing bacterial communities differ between perennial agroecosystem crops
Authors: Sorochkina Kira , Martens-Habbena Willm , Reardon Catherine L , Inglett Patrick W , Strauss Sarah L
Published: April 2024

Biocrusts, common in natural ecosystems, are specific assemblages of microorganisms at or on the soil surface with associated microorganisms extending into the top centimeter of soil. Agroecosystem biocrusts have similar rates of nitrogen (N) fixation as those in natural ecosystems, but it is unclear how agricultural management influences their composition and function. This study examined the total bacterial and diazotrophic communities of biocrusts in a citrus orchard and a vineyard that shared a similar climate and soil type but differed in management. To contrast climate and soil type, these biocrusts were also compared with those from an apple orchard. Unlike natural ecosystem biocrusts, these agroecosystem biocrusts were dominated by proteobacteria and had a lower abundance of cyanobacteria. All of the examined agroecosystem biocrust diazotroph communities were dominated by N-fixing cyanobacteria from the Nostocales order, similar to natural ecosystem cyanobacterial biocrusts. Lower irrigation and fertilizer in the vineyard compared with the citrus orchard could have contributed to biocrust microbial composition, whereas soil type and climate could have differentiated the apple orchard biocrust. Season did not influence the bacterial and diazotrophic community composition of any of these agroecosystem biocrusts. Overall, agricultural management and climatic and edaphic factors potentially influenced the community composition and function of these biocrusts.
Numerical modelling of impact seismic sources using the stress glut theory
Authors: Froment Marouchka , Lognonné Philippe , Larmat Carene , Lei Zhou , Rougier Esteban , Kawamura Taichi
Published: April 2024

Meteorite impacts have proved to be a significant source of seismic signal on the Moon, and have now been recorded on Mars by InSight seismometers. Understanding how impacts produce seismic signal is key to the interpretation of this unique data, and to improve their identification in continuous seismic records. Here, we use the seismic Representation Theorem, and particularly the stress glut theory, to model the seismic motion resulting from impact cratering. The source is described by equivalent forces, some resulting from the impactor momentum transfer, and others from the stress glut, which represents the mechanical effect of plasticity and non linear processes in the source region. We condense these equivalent forces into a point-source with a time-varying single force and nine-component moment tensor. This analytical representation bridges the gap between the complex dynamics of crater formation, and the linear point-source representation classically used in seismology. Using the multiphysics modelling software HOSS, we develop a method to compute the stress glut of an impact, and the associated point-source from hypervelocity impact simulations. For a vertical and an oblique impact at 1000 m s−1, we show that the moment tensor presents a significant deviatoric component. Hence, the source is not an ideal isotropic explosion contrary to previous assumptions, and draws closer to a double couple for the oblique impact. The contribution of the point force to the seismic signal appears negligible. We verify this model by comparing two signals: (1) HOSS is coupled to SPECFEM3D to propagate the near-source signal elastically to remote seismic stations; (2) the point-source model derived from the stress-glut theory is used to generate displacements at the same distance. The comparison shows that the point-source model is accurately simulating the low-frequency impact seismic waveform, and its seismic moment is in trend with Lunar and Martian impact data. High-frequencies discrepancies exist, which are partly related to finite-source effects, but might be further explained by the difference in mathematical framework between classical seismology and HOSS’ numerical modelling.
Evaluating the cost-emissions trade-offs of a modal shift in intermodal and synchromodal transportation planning
Authors: van Staden Heletjé E , Yee Hannah , Boute Robert N
Published: April 2024

Accepted by: Aris Syntetos

Intermodal transportation planning combines road with more sustainable transportation modes to encourage a modal shift. To evaluate the impact of a modal shift on transportation cost and emissions, we propose an intermodal transportation planning model to provide transparency in the cost-emissions trade-off. The model incorporates minimum load requirements, time windows, freight consolidation and stochastic travel times to generate alternative transportation options. It also includes order consolidation to facilitate the utilization of transportation modes that would otherwise be infeasible due to, for instance, minimum load requirements. We also propose a synchromodal planning tool to evaluate re-planning and re-consolidation options in response to disruptions. We numerically illustrate the working of our model using a representative network setting and quantify the trade-offs concerning costs and emissions by evaluating different transportation route options.
Assessment for Antibodies to Rifapentine and Isoniazid in Persons Developing Flu-Like Reactions During Treatment of Latent Tuberculosis Infection
Authors: Moro Ruth N , Mehaffy Carolina , De Prithwiraj , Phillips Elizabeth , Borisov Andrey S , Sterling Timothy R , Dobos Karen M
Published: April 2024

Background

Flu-like reactions can occur after exposure to rifampin, rifapentine, or isoniazid. Prior studies have reported the presence of antibodies to rifampin, but associations with underlying pathogenesis are unclear.

Methods

We evaluated PREVENT TB study participants who received weekly isoniazid plus rifapentine for 3 months (3HP) or daily isoniazid for 9 months (9H) as treatment for Mycobacterium tuberculosis infection. Flu-like reaction was defined as a grade ≥2 of any of flu-like symptoms. Controls (3HP or 9H) did not report flu-like reactions. We developed a competitive enzyme-linked immunosorbent assays (ELISA) to detect antibodies against rifapentine, isoniazid, rifampin, and rifapentine metabolite.

Results

Among 128 participants, 69 received 3HP (22 with flu-like reactions; 47 controls) and 59 received 9H (12 with flu-like reactions; 47 controls). In participants receiving 3HP, anti-rifapentine IgG was identified in 2 of 22 (9%) participants with flu-like reactions and 6 of 47 (13%) controls (P = .7), anti-isoniazid IgG in 2 of 22 (9%) participants with flu-like reactions and 4 of 47 (9%) controls (P = .9). Among participants receiving 9H, IgG and IgM anti-isoniazid antibodies were each present in 4 of 47 (9%) controls, but none among participants with flu-like reactions; anti-rifapentine IgG antibodies were not present in any participants with flu-like reactions or controls.

Conclusions

We detected anti-rifapentine, anti-isoniazid, and anti-rifapentine metabolite antibodies, but the proportions of participants with antibodies were low, and did not differ between participants with flu-like reactions and those without such reactions. This suggests that flu-like reactions associated with 3HP and 9H were not antibody mediated.

Clinical Trials Registration

NCT00023452.
Reconstruction of remodeling units reveals positive effects after 2 and 12 months of romosozumab treatment
Authors: Eriksen Erik F , Boyce Rogely W , Shi Yifei , Brown Jacques P , Betah Donald , Libanati Cesar , Oates Mary , Chapurlat Roland , Chavassieux Pascale
Published: April 2024

Romosozumab treatment results in a transient early increase in bone formation and sustained decrease in bone resorption. Histomorphometric analyses revealed that the primary bone-forming effect of romosozumab is a transient early stimulation of modeling-based bone formation on cancellous and endocortical surfaces. Furthermore, preclinical studies have demonstrated that romosozumab may affect changes in the remodeling unit, resulting in positive bone balance. To further investigate the effects of romosozumab on bone balance, mo 12 (M12) and mo 2 (M2) (to analyze early effects) unpaired bone biopsies from the FRAME clinical trial were analyzed using remodeling site reconstruction to assess whether positive changes in bone balance on cancellous/endocortical surfaces may contribute to the progressive improvement in bone mass/structure and reduced fracture risk in osteoporotic women at high fracture risk. At M12, bone balance was higher with romosozumab vs placebo on cancellous (+6.1 vs +1.5 μm; P = .012) and endocortical (+5.2 vs −1.7 μm; P = .02) surfaces; higher bone balance was due to lower final erosion depth (40.7 vs 43.7 μm; P = .05) on cancellous surfaces and higher completed wall thickness (50.8 vs 47.5 μm; P = .037) on endocortical surfaces. At M2, the final erosion depth was lower on the endocortical surfaces (42.7 vs 50.7 μm; P = .021) and was slightly lower on the cancellous surfaces (38.5 vs 44.6 μm; P = .11) with romosozumab vs placebo. Sector analysis of early endocortical formative sites revealed higher osteoid thickness (29.9 vs 19.2 μm; P = .005) and mineralized wall thickness (18.3 vs 11.9 μm; P = .004) with romosozumab vs placebo. These evolving bone packets may reflect the early stimulation of bone formation that contributes to the increase in completed wall thickness at M12. These data suggest that romosozumab induces a positive bone balance due to its effects on bone resorption and formation at the level of the remodeling unit, contributing to the positive effects on bone mass, structure, and fracture risk.
Measuring and Testing Systemic Risk from the Cross-Section of Stock Returns
Authors: Gil Jaime Jesús , Olmo Jose
Published: April 2024

This study proposes a novel measure of systemic risk that is obtained by aggregating downside risk information from the cross section of assets. In contrast to existing studies, we expand the analysis of systemic risk to many assets and focus on marginal measures of tail risk that are aggregated using a Fisher-type test to detect the risk of systemic events. The presence of downside risk for each asset of the cross section is examined through a bootstrap test of first-order stochastic dominance between the underlying tail distribution and the tail distribution of the residuals of a multivariate DCC-GARCH model. The application of these methods to the cross section of the FTSE-100 stock returns provides overwhelming evidence on the presence of financial instability during the period 2006–2009. Interestingly, we also find compelling evidence of systemic risk during the 2012–2015 period coinciding with the European debt crisis and after the outbreak of the coronavirus disease 2019 pandemic.
The Competition Law and Institutions of the European Union
Authors: Jones Alison , Sufrin Brenda , Dunne Niamh
Published: April 2024

This chapter sketches the history and functions of the EU and its institutions in order to set the EU competition rules in context. It then describes the competition provisions themselves and outlines the way in which the rules are applied and enforced, including the public enforcement of Articles 101 and 102 under Regulation 1/2003, the control of mergers with a European dimension under Regulation 139/2004, public enforcement by the national competition authorities of the Member States, and the role of private enforcement. It discusses the position and powers of the European Commission, particularly the role of the Competition Directorate General (DG Comp); the powers of the EU Courts; the significance of fundamental rights and the general principles of EU law in competition cases; the application of competition rules to particular sectors of the economy; and the application of the EU rules to the EEA.
Article 101 TFEU: The Elements
Authors: Jones Alison , Sufrin Brenda , Dunne Niamh
Published: April 2024

This chapter discusses the text and scheme of Article 101 which prohibits agreements, decisions and concerted practices which restrict competition and may affect trade between Member States. It explains the terms employed in Article 101(1) and how they are interpreted and applied. This entails a discussion of the meaning of ‘undertaking’ and ‘association of undertakings’, including the concepts of ‘economic activities’ and of a ‘single economic entity’; the meaning of ‘agreement’ including the coverage of both horizontal and vertical agreements; the meaning of ‘concerted practice’; the meaning of ‘decisions by associations of undertakings’; the application of Article 101(1) to complex arrangements and single continuous infringements; and the meaning of an appreciable effect on trade between Member States.
Agora: Multicomponent simulation for cross-survey science
Authors: Omori Yuuki
Published: April 2024

Next-generation cosmological surveys will observe large portions of the sky, with significant overlap between them. Multi-wavelength observations will enable us to analyse the same large-scale structure from different angles using a variety of tracers and astrophysical effects. The complex interplay between these observables calls for a model that can accurately and coherently describe their collective behaviour, posing a challenge that can only be met through the use of simulations. In this work, a suite of simulated extragalactic skies is presented, including maps and/or catalogues of cosmic microwave background (CMB) lensing, thermal and kinetic Sunyaev–Zel’dovich (tSZ/kSZ) effects, cosmic infrared background (CIB), radio sources, galaxy overdensity and galaxy weak lensing. Each of these probes is implemented in the lightcone using halo catalogues and/or particles from the Multidark-Planck2 ($\small {MDPL2}$) N-body simulation, and the modelling is calibrated using hydrodynamic simulations and publicly available data. The auto and cross-spectra of the individual probes, as well as the cross-spectra between the observables, are shown to be consistent with theoretical models and measurements from data. The simulation is shown to have a wide range of applications, including forecasting, pipeline testing, and evaluating astrophysical biases in cross-correlation measurements. It is further demonstrated that the simulation products produced in this work have sufficient accuracy to recover the input cosmology when subjected to a full cosmological analysis and are ready for application in real-world analyses for ongoing and future surveys. The simulation products presented in this work can be accessed at: https://yomori.github.io/agora/index.html.
A low-mass helium star progenitor model for the Type Ibn SN 2020nxt
Authors: Wang Qinan , Goel Anika , Dessart Luc , Fox Ori D , Shahbandeh Melissa , Rest Sofia , Rest Armin , Groh Jose H , Allan Andrew , Fransson Claes , Smith Nathan , Hosseinzadeh Griffin , Filippenko Alexei V , Andrews Jennifer , Bostroem K Azalee , Brink Thomas G , Brown Peter , Burke Jamison , Chevalier Roger , Clayton Geoffrey C , Dai Mi , Davis Kyle W , Foley Ryan J , Gomez Sebastian , Harris Chelsea , Hiramatsu Daichi , Howell D Andrew , Jennings Connor , Jha Saurabh W , Kasliwal Mansi M , Kelly Patrick L , Kool Erik C , Liu Evelyn , Ma Emily , McCully Curtis , Miller Adam M , Murakami Yukei , Gonzalez Estefania Padilla , Pellegrino Craig , Perera Derek , Pierel Justin , Rojas-Bravo César , Siebert Matthew R , Sollerman Jesper , Szalai Tamás , Tinyanont Samaporn , Van Dyk Schuyler D , Zheng WeiKang , Chambers Kenneth C , Coulter David A , de Boer Thomas , Earl Nicholas , Farias Diego , Gall Christa , McGill Peter , Ransome Conor L , Taggart Kirsty , Villar V Ashley
Published: April 2024

A growing number of supernovae (SNe) are now known to exhibit evidence for significant interaction with a dense, pre-existing, circumstellar medium (CSM). SNe Ibn comprise one such class that can be characterized by both rapidly evolving light curves and persistent narrow He i lines. The origin of such a dense CSM in these systems remains a pressing question, specifically concerning the progenitor system and mass-loss mechanism. In this paper, we present multiwavelength data of the Type Ibn SN 2020nxt, including HST/STIS ultraviolet spectra. We fit the data with recently updated CMFGEN models designed to handle configurations for SNe Ibn. The UV coverage yields strong constraints on the energetics and, when combined with the CMFGEN models, offer new insight on potential progenitor systems. We find the most successful model is a ≲4 M⊙ helium star that lost its $\sim 1\, {\rm M}_\odot$ He-rich envelope in the years preceding core collapse. We also consider viable alternatives, such as a He white dwarf merger. Ultimately, we conclude at least some SNe Ibn do not arise from single, massive (>30 M⊙) Wolf–Rayet-like stars.
Cosmological parameters estimated from peculiar velocity–density comparisons: calibrating 2M++
Authors: Hollinger Amber M , Hudson Michael J
Published: April 2024

Cosmological parameters can be measured by comparing peculiar velocities with those predicted from a galaxy density field. Previous work has tested the accuracy of this approach with N-body simulations, but generally on idealized mock galaxy surveys. However, systematic biases may arise solely due to survey selection effects such as flux-limited samples, edge-effects, and complications due to the obscuration of the Galactic plane. In this work, we explore the impact of each of these effects individually as well as collectively using the semi-analytic models from numerical simulations to generate mock catalogues that mimic the 2M++ density field. We find the reconstruction and analysis methods used for our 2M++ mocks produce a value of fσ8 that is biased high by a factor 1.04 ± 0.01 compared to the true value. Moreover, a cosmic volume matching that of 2M++ has a cosmic variance uncertainty in fσ8 of $\sim 5~{{\ \rm per\ cent}}$. The systematic bias is a function of distance: it is unbiased close to the origin but is biased slightly high for distances in the range 100–180 h−1 Mpc. Correcting for this small bias, we find that recent peculiar velocity samples yield $f\sigma _8^{\textrm {lin}} = 0.362\pm 0.023$, a value that is in tension with the extrapolations from cosmic microwave background measurements. The predicted peculiar velocities from 2M++ have an error of 170 km s−1 that slowly increases with distance, exceeding 200 km s−1 only at distances of 180–200 h−1Mpc. Finally, the residual bulk flow speeds found in previous work are shown to be not in conflict with those expected in the Λ cold dark matter model.
How phytochemicals influence reproductive outcomes in women receiving assisted reproductive techniques: a systematic review
Authors: Kircali-Haznedar Nagihan , Mumusoglu Sezcan , Bilgic Pelin
Published: April 2024

Context

Over the past few years, there has been an increasing amount of scholarly literature suggesting a connection between the nutritional status of pregnant mothers and early fetal development, as well as the long-term health consequences of their offspring. Multiple studies have documented that alterations in dietary patterns prior to conception have the potential to affect the initial stages of embryonic development.

Objectives

The aim of this study was to perform a comprehensive review of the research pertaining to the correlation between phytochemicals ( specifically, polyphenols, carotenoids and phytoestrogens) and assisted reproductive technology (ART).

Data sources

PubMed, Scopus, Web of Science, and Clinical Trials databases were searched from January 1978 to March 2023.

Study Selection

This study comprised observational, randomized controlled, and cohort studies that examined the effects of phytochemicals on ART results. The study's outcomes encompass live birth rate, clinical pregnancy, and ongoing pregnancy.

Data extraction

The assessment of study quality was conducted by 2 researchers, independently, using the Quality Criteria Checklist for Primary Research.

Results

A total of 13 studies were included, of which there were 5 randomized controlled studies, 1 nonrandomized controlled study, 6 prospective cohort studies, and 1 retrospective cohort study.

Conclusion

This research focused on investigating the impact of phytochemicals on ART and has highlighted a dearth of articles addressing that topic. Collaboration among patients, physicians, and nutritionists is crucial for doing novel research.

Systematic Review Registration

PROSPERO registration no. CRD42023426332.