bluuebunny/crossref_metadata_2025 huggingface dataset:
Classification of solutions of the 2D steady Navier-Stokes equations with separated variables in cone-like domains
Authors: Wang Wendong , Wu Jie
Published: April 2023

We investigate the problem of classification of solutions for the steady Navier–Stokes equations in any cone-like domain. In the form of separated variables,

u
(
x
,
y
)
=

φ
1

(
r
)

v
1

(
θ
)

φ
2

(
r
)

v
2

(
θ
)

,

where

x
=
r
cos
θ

and

y
=
r
sin
θ

in the polar coordinates, we obtain the expressions of all smooth solutions with C
0 Dirichlet boundary condition. In particular, we find some solutions which are Hölder continuous on the boundary but their gradients blow up at the corner, show that all solutions in the entire plane

R

2

must be polynomials, and prove a sharp Liouville type theorem.
Lower bounds on the Hausdorff dimension of some Julia sets
Authors: Dudko Artem , Gorbovickis Igors , Tucker Warwick
Published: April 2023

We present an algorithm for a rigorous computation of lower bounds on the Hausdorff dimensions of Julia sets for a wide class of holomorphic maps. We apply this algorithm to obtain lower bounds on the Hausdorff dimension of the Julia sets of some infinitely renormalizable real quadratic polynomials, including the Feigenbaum polynomial

p

F
e
i
g

(
z
)
=

z
2

+

c

F
e
i
g

. In addition to that, we construct a piecewise constant function on

[
−
2
,
2
]

that provides rigorous lower bounds for the Hausdorff dimension of the Julia sets of all quadratic polynomials

p
c

(
z
)
=

z
2

+
c

with

c
∈
[
−
2
,
2
]

. Finally, we verify the conjecture of Ludwik Jaksztas and Michel Zinsmeister that the Hausdorff dimension of the Julia set of a quadratic polynomial

p
c

(
z
)
=

z
2

+
c

, is a C
1-smooth function of the real parameter c on the interval

c
∈
(

c

F
e
i
g

,
−
3

/

4
)

.
Effects of head modeling errors on the spatial frequency representation of MEG
Authors: Yeo Wan-Jin , Larson Eric , Iivanainen Joonas , Borna Amir , McKay Jim , Stephen Julia M , Schwindt Peter D D , Taulu Samu
Published: April 2023

Objectives. We aim to investigate the effects of head model inaccuracies on signal and source reconstruction accuracies for various sensor array distances to the head. This allows for the assessment of the importance of head modeling for next-generation magnetoencephalography (MEG) sensors, optically-pumped magnetometers (OPM). Approach. A 1-shell boundary element method (BEM) spherical head model with 642 vertices of radius 9 cm and conductivity of 0.33 S m−1 was defined. The vertices were then randomly perturbed radially up to 2%, 4%, 6%, 8% and 10% of the radius. For each head perturbation case, the forward signal was calculated for dipolar sources located at 2 cm, 4 cm, 6 cm and 8 cm from the origin (center of the sphere), and for a 324 sensor array located at 10 cm to 15 cm from the origin. Equivalent current dipole (ECD) source localization was performed for each of these forward signals. The signal for each perturbed spherical head case was then analyzed in the spatial frequency domain, and the signal and ECD errors were quantified relative to the unperturbed case. Main results. In the noiseless and high signal-to-noise ratio (SNR) case of approximately ≥6 dB, inaccuracies in our spherical BEM head conductor models lead to increased signal and ECD inaccuracies when sensor arrays are placed closer to the head. This is true especially in the case of deep and superficial sources. In the noisy case however, the higher SNR for closer sensor arrays allows for an improved ECD fit and outweighs the effects of head geometry inaccuracies. Significance. OPMs may be placed directly on the head, as opposed to the more commonly used superconducting quantum interference device sensors which must be placed a few centimeters away from the head. OPMs thus allow for signals of higher spatial resolution to be captured, resulting in potentially more accurate source localizations. Our results suggest that an increased emphasis on accurate head modeling for OPMs may be necessary to fully realize its improved source localization potential.
A CNN-based four-layer DOI encoding detector using LYSO and BGO scintillators for small animal PET imaging
Authors: He Wen , Zhao Yangyang , Zhao Xin , Huang Wenjie , Zhang Lei , Prout David L , Chatziioannou Arion F , Ren Qiushi , Gu Zheng
Published: April 2023

Objective. We propose a novel four-layer depth-of-interaction (DOI) encoding phoswich detector using lutetium–yttrium oxyothosilicate (LYSO) and bismuth germanate (BGO) scintillator crystal arrays for high sensitivity and high spatial resolution small animal PET imaging. Approach. The detector was comprised of a stack of four alternating LYSO and BGO scintillator crystal arrays coupled to an 8 × 8 multi-pixel photon counter (MPPC) array and read out by a PETsys TOFPET2 application specific integrated circuit. The four layers from the top (gamma ray entrance) to the bottom (facing the MPPC) consisted of a 24 × 24 array of 0.99 × 0.99 × 6 mm3 LYSO crystals, a 24 × 24 array of 0.99 × 0.99 × 6 mm3 BGO crystals, a 16 × 16 array of 1.53 × 1.53 × 6 mm3 LYSO crystals and a 16 × 16 array of 1.53 × 1.53 × 6 mm3 BGO crystals. Main results. Events that occurred in the LYSO and BGO layers were first separated by measuring the pulse energy (integrated charge) and duration (time over threshold (ToT)) from the scintillation pulses. Convolutional neural networks (CNNs) were then used to distinguish between the top and lower LYSO layers and between the upper and bottom BGO layers. Measurements with the prototype detector showed that our proposed method successfully identified events from all four layers. The CNN models achieved a classification accuracy of 91% for distinguishing the two LYSO layers and 81% for distinguishing the two BGO layers. The measured average energy resolution was 13.1% ± 1.7% for the top LYSO layer, 34.0% ± 6.3% for the upper BGO layer, 12.3% ± 1.3% for the lower LYSO layer, and 33.9% ± 6.9% for the bottom BGO layer. The timing resolution between each individual layer (from the top to the bottom) and a single crystal reference detector was 350 ps, 2.8 ns, 328 ps, and 2.1 ns respectively. Significance. In conclusion, the proposed four-layer DOI encoding detector achieved high performance and is an attractive choice for next-generation high sensitivity and high spatial resolution small animal positron emission tomography systems.
A deep learning-based approach for statistical robustness evaluation in proton therapy treatment planning: a feasibility study
Authors: Vazquez Ivan , Gronberg Mary P , Zhang Xiaodong , Court Laurence E , Zhu X Ronald , Frank Steven J , Yang Ming
Published: April 2023

Objective. Robustness evaluation is critical in particle radiotherapy due to its susceptibility to uncertainties. However, the customary method for robustness evaluation only considers a few uncertainty scenarios, which are insufficient to provide a consistent statistical interpretation. We propose an artificial intelligence–based approach that overcomes this limitation by predicting a set of percentile dose values at every voxel and allows for the evaluation of planning objectives at specific confidence levels. Approach. We built and trained a deep learning (DL) model to predict the 5th and 95th percentile dose distributions, which corresponds to the lower and upper bounds of a two-tailed 90% confidence interval (CI), respectively. Predictions were made directly from the nominal dose distribution and planning computed tomography scan. The data used to train and test the model consisted of proton plans from 543 prostate cancer patients. The ground truth percentile values were estimated for each patient using 600 dose recalculations representing randomly sampled uncertainty scenarios. For comparison, we also tested whether a common worst-case scenario (WCS) robustness evaluation (voxel-wise minimum and maximum) corresponding to a 90% CI could reproduce the ground truth 5th and 95th percentile doses. Main results. The percentile dose distributions predicted by DL yielded excellent agreements with the ground truth dose distributions, with mean dose errors below 0.15 Gy and average gamma passing rates (GPR) at 1 mm/1% above 93.9, which were substantially better than the WCS dose distributions (mean dose error above 2.2 Gy and GPR at 1 mm

/

1% below 54). We observed similar outcomes in a dose-volume histogram error analysis, where the DL predictions generally yielded smaller mean errors and standard deviations than the WCS evaluation doses. Significance. The proposed method produces accurate and fast predictions (∼2.5 s for one percentile dose distribution) for a given confidence level. Thus, the method has the potential to improve robustness evaluation.
Numerical analysis of twisted ion-acoustic waves
Authors: Naqvi Tehreem , Bukhari S , Ali S , Aman-ur-Rehman
Published: April 2023

Twisted ion-acoustic waves with finite orbital angular momentum (OAM) states are numerically investigated in a plasma containing electrons, positrons and dynamical ions. For this purpose, the well-known Vlasov–Poisson equations are solved together under the paraxial approximation. The perturbed quantities are assumed to follow the Laguerre–Gaussian type solutions and a generalized plasma response function for finite OAM states is derived. The generalized response function is numerically analyzed to investigate dispersion characteristics of the twisted ion-acoustic waves. Consequently, a computer code is developed which is based on the very famous numerical technique known as the Newton–Raphson method. The dependence of the (real) wave oscillation frequency and damping rate involving the twisted ion-acoustic waves is highlighted with different plasma parameters. It is found that the dynamics of ion-acoustic waves are strongly influenced by the twist parameter owing to OAM states. The results obtained in the present study are useful in the understanding of the particle transport and trapping phenomena.
Destabilization mechanism of the collisional microtearing mode in magnetized slab plasmas
Authors: Yagyu Mitsuyoshi , Numata Ryusuke
Published: April 2023

The destabilization mechanism of the collisional microtearing mode driven by an electron temperature gradient is studied using theoretical analyses and gyrokinetic simulations including a comprehensive collision model, in magnetized slab plasmas. The essential destabilization mechanism of the microtearing mode is the lag of the parallel inductive electric field behind the magnetic field owing to the time-dependent thermal force and inertia force induced by the velocity-dependent electron–ion collisions. Quantitative measurements of the collision effects enable us to identify the unstable regime against collisionality and reveal the relevance of the collisional microtearing mode with existing toroidal experiments. A nonlinear simulation demonstrates that the microtearing mode does not drive magnetic reconnection with the explosive release and conversion of the magnetic energy.
A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures
Authors: Fang Zhou
Published: April 2023

An axisymmetric guided wave mode is excited independently within a circular tube structure to reduce the complexity of signal interpretation through the prevention of unwanted wave polarisations and reflections. However, it is difficult to use the axisymmetric guided wave to determine the circumferential position and coverage of a defect within the circular tube structure. Non-axisymmetric guided waves can be used to mitigate the limitation of the axisymmetric guided wave through the adoption of a partially covered transducer design and analysis of the propagation characteristics. The partial excitation of non-axisymmetric guided waves can facilitate the arrangement of a transducer during defect detection. This paper reviews state-of-the-art research on non-axisymmetric guided waves for determining the axial positions, circumferential positions, and circumferential lengths of defects. First, the fundamental analysis of a specific non-axisymmetric guided wave mode based on the normal mode expansion method and beam directivity analysis method reveals that the propagation characteristics of the wave mode are closely related to the working principle and configuration of the corresponding transducer. Then, the advantages and disadvantages of the different types of transducers and transducer arrays for the excitation of non-axisymmetric guided waves are introduced and discussed. Finally, the current defect detection methods based on non-axisymmetric guided waves are discussed and summarised. This review can promote the application of non-axisymmetric guided waves in defect detection.
Study on pipeline corrosion monitoring based on piezoelectric active time reversal method
Authors: Yang Dan , Zhang Xinyi , Wang Tao , Lu Guangtao , Peng Yi
Published: April 2023

Pipeline corrosion, especially inner wall corrosion, will cause serious safety accidents. It is important to monitor the corrosion inside the pipeline to reduce the potential risk. Considering the thickness of the pipe wall will become thinner due to the corrosion which will cause the attenuation of the propagated ultrasonic signal energy. Based on this, a novel method for real-time monitoring of pipeline inner wall corrosion using piezoelectric active sensing technology combined with time reversal method is proposed. Two PZT patches are bonded on the outer surface of the pipe as an actuator and a sensor to generate and receive ultrasonic signals propagating in the pipeline wall, respectively. With the time reversal method, the received response signal is reversed in the time domain and then re-emitted as an excitation signal again. Then the time reversal focused signal which represents the signal energy is obtained. By analyzing the received signal energy, that is the focused signal peak, the corrosion state in the inner wall of pipeline can be judged. Experiments are performed to verify the proposed method. In the experiments, the electrochemical corrosion is used to generate the occurrence and evolution of erosion inside the pipeline. Eight different corrosion states of three sample pipelines were studied at different corrosion time. The experimental results show that the peak amplitude of the focused signal decreases with the increase of corrosion time with good repeatability. The method is feasible in pipeline corrosion monitoring, especially in monitoring of the early pipeline corrosion, which has a good application prospect.
Phononic-subsurface flow stabilization by subwavelength locally resonant metamaterials
Authors: Kianfar Armin , Hussein Mahmoud I
Published: April 2023

The interactions between a solid surface and a fluid flow underlie dynamical processes relevant to air, sea, and land vehicle performance and numerous other technologies. Key among these processes are unstable flow disturbances that contribute to fundamental transformations in the flow field. Precise control of these disturbances is possible by introducing a phononic subsurface (PSub). This comprises locally attaching a finite phononic structure nominally perpendicular to an elastic surface exposed to the flowing fluid. This structure experiences ongoing excitation by an unstable flow mode, or more than one mode, traveling in conjunction with the mean flow. The excitation generates small deformations at the surface that trigger elastic wave propagation within the structure, traveling away from the flow and reflecting at the end of the structure to return to the fluid-structure interface and back into the flow. By targeted tuning of the unit-cell and finite-structure characteristics of the PSub, the returning waves may be devised to resonate and reenter the flow out of phase, leading to significant destructive interference of the continuously incoming flow waves near the surface and subsequently to their attenuation over the spatial extent of the control region. This entire mechanism is passive, responsive, and engineered offline without needing coupled fluid-structure simulations; only the flow instability’s frequency, wavelength, and overall modal characteristics must be known. Disturbance stabilization in a wall-bounded transitional flow leads to delay in laminar-to-turbulent transition and reduction in skin-friction drag. Destabilization is also possible by alternatively designing the PSub to induce constructive interference, which is beneficial for delaying flow separation and enhancing chemical mixing and combustion. In this paper, we present a PSub in the form of a locally resonant elastic metamaterial, designed to operate in the elastic subwavelength regime and hence being significantly shorter in length compared to a phononic-crystal-based PSub. This is enabled by utilizing a sub-hybridization resonance. Using direct numerical simulations of channel flows, both types of PSubs are investigated, and their controlled spatial and energetic influence on the wall-bounded flow behavior is demonstrated and analyzed. We show that the PSub’s effect is spatially localized as intended, with a rapidly diminishing streamwise influence away from its location in the subsurface.
Interplay of noise, memory and entangling operator in quantum Stackelberg-Bertrand duopoly game
Authors: Kameshwari A V S , Balakrishnan S
Published: April 2023

In this work, we make an attempt to understand how noise, memory and entangling operators collectively decide the profit of the firms Here we have studied the quantum version of Stackelberg-Bertrand duopoly game using modified EWL scheme in both correlated and uncorrelated noise channels. When this game is analyzed for amplitude damping channels following interesting results are obtained: Firstly, decoherence in channel 2 effects the profit function of the firms more than that of channel 1. Secondly, in the case of correlated noise memory prevents the death of entanglement at maximum noise. Finally, the profit function of the firms depends upon noise, memory, strategies, and entangling operator in any given game setting.
Photonic crystal with magnified resonant peak for biosensing applications
Authors: Zaky Zaky A , Al-Dossari M , Saleh Nahla , Abdelhady Maha M , Sharma Arvind , Zhaketov V D , Aly Arafa H
Published: April 2023

A theoretically and numerically photonic crystal structure with parity-time symmetry is investigated to realize the design of a biomedical sensor for biosensing applications. The transmittance spectra of the structure are investigated, and various performance parameters are evaluated. Different structure parameters such as the unit cell number, the thickness of the sample layer, macroscopic Lorentz oscillation intensity in the PT-symmetry unit cell, the porosity of gallium nitride, and incident angle are theoretically and numerically investigated. To improve the performance of the device, an optimization technique is used. The relatively high sensitivities of 496 nm RIU (the change in the resonant peak wavelength per refractive index unit) and 1002142%/RIU (the change in the transmittance of the resonant peak per refractive index unit) are achieved. The proposed device can be a relatively high-precision detection device for biosensing applications.
Baryogenesis inspired by some modified entropies
Authors: Saleem R , Saleem Aqsa
Published: April 2023

Entropy is defined as a measure of the degree of disorder or randomness in a system and is expressed in thermodynamic terms as the inability of thermal energy to be converted into mechanical work. In this work, we use different types of entropies such as Barrow entropy (BE), Sharma-Mittal entropy (SME), and generalized construction of these entropies. We use the above-mentioned entropies to discuss the issue of baryogenesis and then we find constraints on the entropies parameters to get the physical results of

n

B

S

compared to the standard observational value. To derive the modified Friedmann field equations (FFEs), we use entropies and the first law of thermodynamics. Thus, even in the presence of the typical interaction between the Ricci scalar and baryon current, this results in non-trivial modifications to the mass density and pressure content of the Universe, which provides a viable mechanism allowing for baryogenesis. Finally, we show that even in the radiation-dominant era baryon asymmetry factor (BAF) is non-zero. We conclude, BE parameter 0 ≤ Δ < 1, SME parameters R and δ with positive δ ≥ 4.2 × 1038 (keeping fixed R = 1) while at constant δ = 9 × 1028 for all values of R and for the generalized entropy parameter positive β ≤ 2.4 × 10−28 (fixing γ = α = 5); α ≤ 3.5 × 10−23 (for γ = 1.2 and β = 3) and γ ≥ 1.1 × 106 (at α = 3 × 10−20, β = 3), we have physically desired results on the observational ground.
Optically controllable high-frequency photonic band gaps using modified superradiance lattice
Authors: Shabbir Atif , Qamar Sajid
Published: April 2023

We report that modified superradiance lattice (2023, Phys. Scr.
98 015 105) can be used to obtain high-frequency photonic band gaps which are controllable using low-frequency light. Here, we also notice that the maximum reflectivity of these photonic band gaps can be achieved via low-frequency light control. This maximum reflectivity remains constant for a certain range of probe detuning depending upon the strength of the control field. We also report that this can lead to experimental realization of the soft x-ray regime (high-frequency) via 61st-order low-frequency light using Be2+ ions, the corresponding reflectivity in this case is 96%. Therefore, one can construct controllable x-ray photonic band gaps which can further be used to devise optical switches, beam splitters, and frequency combs. Moreover, this scheme holds the promise of working efficiently in all types of other configurations where reflection of high-frequency light is needed using nth order low-frequency light.
Exact Bianchi type-I inflationary model with non-minimally coupled scalar field
Authors: Bairagi Mithun
Published: April 2023

In the present work, we try to build up an inflationary model within the framework of Bianchi type-I spacetime using a non-minimally coupled, homogeneous, self-interacting canonical scalar field. Specifically, using the Lie symmetry method, we are able to find some novel exact solutions to the Einstein field equations by assuming a power-law relationship between the scalar field and average scale factor. These symmetry-based solutions have been used to derive the values of some important parameters of the anisotropic universe. In this anisotropic model, we find that the volume of space expands with time in an inflationary scenario, depicting the Universe’s accelerating phases. An important characteristic of this model is that it initially represents anisotropic spacetime and then isotropizes the spacetime as time goes on, which favors recent cosmological observations.
Stability of non-degenerate Ricci-type Palatini theories
Authors: Annala Jaakko , Räsänen Syksy
Published: April 2023

We study the stability of theories where the gravitational action has arbitrary algebraic dependence on the three first traces of the Riemann tensor: the Ricci tensor, the co-Ricci tensor, and the homothetic curvature tensor. We collectively call them Ricci-type tensors. We allow arbitrary coupling to matter. We consider the case when the connection is unconstrained, and the cases when either torsion or non-metricity is assumed to vanish. We find which combinations of Ricci-type tensors lead to new degrees of freedom around Minkowski and FLRW space, and when there are ghosts. None of the theories with new degrees of freedom are healthy, except the previously known case when torsion is zero and the action depends only on the Ricci tensor. We find that projective invariance is not a sufficient condition for a theory to be ghost-free.
Scale-dependent gravitational couplings in Parameterised Post-Newtonian Cosmology
Authors: Thomas Daniel B. , Clifton Timothy , Anton Theodore
Published: April 2023

Parameterised Post-Newtonian Cosmology (PPNC) is a theory-agnostic framework for testing gravity in cosmology, which connects gravitational physics on small and large scales in the Universe. It is a direct extension of the Parameterised Post-Newtonian (PPN) approach to testing gravity in isolated astrophysical systems, and therefore allows constraints on gravity from vastly different physical regimes to be compared and combined. We investigate the application of this framework to a class of example scalar-tensor theories of gravity in order to verify theoretical predictions, and to investigate for the first time the scale-dependence of the gravitational couplings that appear within its perturbation equations. In doing so, we evaluate the performance of some simple interpolating functions in the transition region between small and large cosmological scales, as well as the uncertainties that using such functions would introduce into the calculation of observables. We find that all theoretical predictions of the PPNC framework are verified to high accuracy in the relevant regimes, and that simple interpolating functions perform well (but not perfectly) between these regimes. This study is an important step towards being able to use the PPNC framework to analyse cosmological datasets, and to thereby test if/how the gravitational interaction has changed as the Universe has evolved.
Time-delayed neutrino emission from supernovae as a probe of dark matter-neutrino interactions
Authors: Carpio Jose Alonso , Kheirandish Ali , Murase Kohta
Published: April 2023

Thermal MeV neutrino emission from core-collapse supernovae offers a unique opportunity to
probe physics beyond the Standard Model in the neutrino sector. The next generation of neutrino
experiments, such as DUNE and Hyper-Kamiokande, can detect 𝒪(103) and
𝒪(104) neutrinos in the event of a Galactic supernova, respectively. As supernova
neutrinos propagate to Earth, they may interact with the local dark matter via hidden mediators
and may be delayed with respect to the initial neutrino signal. We show that for sub-MeV dark
matter, the presence of dark matter-neutrino interactions may lead to neutrino echoes with
significant time delays. The absence or presence of this feature in the light curve of MeV
neutrinos from a supernova allows us to probe parameter space that has not been explored by dark
matter direct detection experiments.
Probing the interaction between dark energy and dark matter with future fast radio burst observations
Authors: Zhao Ze-Wei , Wang Ling-Feng , Zhang Ji-Guo , Zhang Jing-Fei , Zhang Xin
Published: April 2023

Interacting dark energy (IDE) scenario assumes that there exists a direct interaction between dark energy and cold dark matter, but this interaction is hard to be tightly constrained by the current data. Fast radio bursts (FRBs) will be seen in large numbers by future radio telescopes, and thus they have potential to become a promising low-redshift cosmological probe. In this work, we investigate the capability of future FRBs of constraining the dimensionless coupling parameter β in four phenomenological IDE models. If we fix the FRB properties, about 105 FRB data can give constraints on β tighter than the current cosmic microwave background data in the IDE models with the interaction proportional to the energy density of dark energy. In all the IDE models, about 106 FRB data can achieve the absolute errors of β to less than 0.10, providing a way to precisely measure β by only one cosmological probe. Jointly constraining the FRB properties and cosmological parameters would increase the constraint errors of β by a factor of about 0.5–2.
Angular distribution of low momentum atmospheric muons at ground level
Authors: Briki I. , Mazouz M. , Ghedira L.
Published: April 2023

We report measurements of the angular distributions of low momentum atmospheric muons at
38 m above sea level for zenith angles θ between -60 and 60 degrees in the south-north
direction. The muon detection was performed with two NaI(Tl) scintillation detectors mounted in
coincidence. An adjustable lead thickness placed between the detectors allowed to select muons
with a minimal momentum ranging from 0.3 to 0.9 GeV/c. The integrated and the differential muon
flux were determined by analyzing the deposited energy spectra in the scintillators backed up by a
Geant4 simulation of the experimental setup. The results are consistent with the
cos
n
(θ) distribution in good agreement with the literature. These data contribute to
fill the gap in the geomagnetic cutoff rigidity interval 8 GV < Pc
< 14 GV where no similar
measurements were performed before. We found that n = 1.88 - 0.12 Pμ
c
in this domain of muon
momenta cutoff Pμ
c
< 1 GeV/c. The present measurements are useful for many muon studies
requiring an accurate integrated flux.
Astrophysical plasma instabilities induced by long-range interacting dark matter
Authors: Cruz Akaxia , McQuinn Matthew
Published: April 2023

If dark matter is millicharged or darkly charged, collective plasma processes may dominate
momentum exchange over direct particle collisions. In particular, plasma streaming instabilities
can couple the momentum of the dark matter to counter-streaming baryons or other dark matter and
result in the counter-streaming fluids coming to rest with each other, just as happens for
baryonic collisionless shocks in astrophysical systems. While electrostatic plasma instabilites
(such as the two-stream) are highly suppressed by Landau damping when dark matter is millicharged,
in the cosmological situations of interest, electromagnetic instabilities such as the Weibel can
couple the momenta, assuming that the linear instability saturates in the manner typically found
for baryonic plasmas. We find that the streaming of dark matter in the pre-Recombination universe
is affected more strongly by direct collisions than collective processes, validating previous
constraints. However, when considering unmagnetized instabilities the properties of the Bullet
Cluster merger and other merging cluster systems (which show dark matter streaming through itself)
are likely to be substantially altered if [qχ
/mχ
] ≳ 10-4, where
[qχ
/mχ
] is the charge-to-mass ratio of the dark matter relative to that of the proton.
When a magnetic field is added consistent with cluster observations, the Weibel and Firehose
instabilities result in sufficiently fast growth to reach saturation for [qχ
/mχ
] ≳ 
10-12–10-11. The Weibel growth rates are even faster in the case of a dark-U(1) charge
(because “hot” electrons do not damp the instability), potentially ruling out [qχ
/mχ
]
 ≳ 10-14 in the Bullet Cluster system, in agreement with [1]. The
strongest previous limits on millicharged dark matter (mDM) arise from considering the spin-down
of galactic disks [2]. We show that plasma instabilities or tangled background
magnetic fields could lead to diffusive propagation of the dark matter, weakening these spin-down
limits. Thus, plasma instabilities may place some of the most stringent constraints over much of
the millicharged, and our results corroborate previous extremely stringent potential constraints
on the dark-charged parameter space.
Phantom scalar-tensor models and cosmological tensions
Authors: Ballardini Mario , Ferrari Angelo Giuseppe , Finelli Fabio
Published: April 2023

We study three different extended scalar-tensor theories of gravity by also allowing a negative sign for
the kinetic term for the scalar field in the Jordan frame. Our scope is to understand how the observational
constraints for these models cope with the volume of the parameter space in which the theory is healthy.
Models with a negative kinetic term lead to decreasing effective gravitational constant with redshift and
behave as an effective relativistic component with a negative energy density as opposite to their corresponding
version with a standard kinetic term. As a consequence, we find that the extended branch with a negative sign
for the kinetic term correspond in general to lower H
0 and σ
8 compared to ΛCDM. We find
that in all the cases with a negative sign for the kinetic term studied here, cosmological observations
constrain these models around GR and prefer a volume of the parameter space in which the theory is not healthy
since the scalar field behave as a ghost also in the related Einstein frame.
We show that also in the phantom branch early modify gravity with a quartic coupling can substantially
reduce the H
0 tension fitting the combination of cosmic microwave background data from Planck,
baryon acoustic oscillations from BOSS and eBOSS, and Supernovae from the Pantheon sample with calibration
information by SH0ES.
Using EEG signals to assess workload during memory retrieval in a real-world scenario
Authors: Chiang Kuan-Jung , Dong Steven , Cheng Chung-Kuan , Jung Tzyy-Ping
Published: April 2023

Objective. The electroencephalogram (EEG) is gaining popularity as a physiological measure for neuroergonomics in human factor studies because it is objective, less prone to bias, and capable of assessing the dynamics of cognitive states. This study investigated the associations between memory workload and EEG during participants’ typical office tasks on a single-monitor and dual-monitor arrangement. We expect a higher memory workload for the single-monitor arrangement. Approach. We designed an experiment that mimics the scenario of a subject performing some office work and examined whether the subjects experienced various levels of memory workload in two different office setups: (1) a single-monitor setup and (2) a dual-monitor setup. We used EEG band power, mutual information, and coherence as features to train machine learning models to classify high versus low memory workload states. Main results. The study results showed that these characteristics exhibited significant differences that were consistent across all participants. We also verified the robustness and consistency of these EEG signatures in a different data set collected during a Sternberg task in a prior study. Significance. The study found the EEG correlates of memory workload across individuals, demonstrating the effectiveness of using EEG analysis in conducting real-world neuroergonomic studies.
A low-power 1 Gb/s line driver with configurable pre-emphasis for
lossy transmission lines
Authors: St. John N. , Mandal S. , Miryala S. , Maj P. , Deptuch G.W. , Raguzin E. , Rescia S.
Published: April 2023

A line driver with configurable pre-emphasis is implemented in a 65 nm
CMOS process. The driver utilizes a three-tap feed-forward equalization
architecture. The relative delays between the taps are selectable in increments
of 1/16th of the unit interval via an 8-stage delay-locked loop and digital
interpolator. It is also possible to control the output amplitude and source
impedance for each tap via a programmable array of eight source-series
terminated drivers. The entire design consumes 9 mW from a 1.2 V supply
at 1 Gb/s.
Inductively-coupled plasma discharge for use in high-energy-density science
experiments
Authors: Arrowsmith C.D. , Dyson A. , Gudmundsson J.T. , Bingham R. , Gregori G.
Published: April 2023

Inductively-coupled plasma discharges are well-suited as
plasma sources for experiments in fundamental high-energy density
science, which require large volume and stable plasmas. For example,
experiments studying particle beam-plasma instabilities and the
emergence of coherent macroscopic structures — which are key for
modelling emission from collisionless shocks present in many
astrophysical phenomena. A meter-length, table-top, inductive
radio-frequency discharge has been constructed for use in a
high-energy density science experiment at CERN which will study
plasma instabilities of a relativistic electron-positron beam. In
this case, a large volume is necessary for the beam to remain inside
the plasma as it diverges to centimeter-scale diameters during the
tens-of-centimeters of propagation needed for instabilities to
develop. Langmuir probe measurements of the plasma parameters show
that plasma can be stably sustained in the discharge with electron
densities exceeding 1011 cm-3. The discharge has been
assembled using commercially-available components, making it an
accessible option for commissioning at a University laboratory.
The upgrade of the ASACUSA scintillating bar detector for antiproton annihilation measurements
Authors: Costantini Giovanni , Giorleo Luca , Gosta Giulia , Leali Marco , Mascagna Valerio , Migliorati Stefano , Prest Michela , Ronchetti Federico , Solazzi Luigi , Vallazza Erik , Venturelli Luca
Published: April 2023

Antiproton annihilations on matter nuclei are usually detected by tracking the charged pions emitted in the process. A detector made of plastic scintillating bars have been built and used in the ASACUSA experiment for the last 10 years. Ageing, movements and transports caused stress on the internal mechanical structure and impacted mostly on the optical readout system which was eventually upgraded: the so far used multi-anode photo-multiplier tubes (PMTs) have been replaced by silicon photomultipliers (SiPM) and the front-end electronics had to be adapted to cope with the new signal formation. This work describes the design and operations of the upgrade, as well as the validation tests with cosmic rays.
Magnetic shielding for large photoelectron multipliers for the OSIRIS facility of the JUNO detector
Authors: Smirnov O. , Korablev D. , Sotnikov A. , Stahl A. , Steinmann J. , Khudyakov V. , Avetissov I. , Zykova M.
Published: April 2023

We present technical design and characteristics of the magnetic shield developed for 20"
PMTs of the low-background OSIRIS facility. A ribbon of amorphous alloy with extreme magnetic
permeability was used in its design, providing excellent efficiency in screening the Earth's
magnetic field with a relatively small amount of material. The mass of materials is crucial to
construction of low-background facilities because of radioactive backgrounds. Using amorphous
materials is cost-efficient compared to other methods for screening the Earth's magnetic field.
CO2 fertilization effect may balance climate change impacts on oil palm cultivation
Authors: Beringer Tim , Müller Christoph , Chatterton Julia , Kulak Michal , Schaphoff Sibyll , Jans Yvonne
Published: April 2023

Oil palm cultivation has become one of the world’s most important drivers of land use change in the tropics causing biodiversity loss and greenhouse gas emissions. The impact of climate change and rising carbon dioxide (CO2) concentrations in the atmosphere on oil palm productivity is not well understood. If environmental change leads to declining palm oil yields in existing cultivation areas, cultivation areas may expand or shift to other regions. Here we assess climate change impacts on palm oil production using an extended version of the dynamic global vegetation model with managed land, LPJmL4, and a range of climate scenarios from the inter-sectoral impact model intercomparison project. We find increasing average yields under all future climate scenarios. This contradicts earlier studies, which did not consider the potential positive effect of CO2 fertilization. If we do not account for CO2 fertilization, future yields also decrease in our simulations. Our results indicate the potentially large role of rising CO2 levels on oil palm cultivation. This highlights the importance of further applied plant science to better understand the impact of climate change and elevated CO2 levels on oil palm growth and productivity.
Association between one-year exposure to air pollution and the prevalence of pulmonary nodules in China
Authors: Cao Yuanyuan , Sun Tao , Wang Zhanpeng , Lei Fang , Lin Lijin , Zhang Xingyuan , Song Xiaohui , Zhang Xiao-Jing , Zhang Peng , She Zhi-Gang , Cai Jingjing , Yang Shujuan , Jia Peng , Li Jian , Li Hongliang
Published: April 2023

PM2.5 is a well-known airborne hazard to cause various diseases. Evidence suggests that air pollution exposure contributes to the occurrence of pulmonary nodules. Pulmonary nodules detected on the computed tomography scans can be malignant or progress to malignant during follow-up. But the evidence of the association between PM2.5 exposure and pulmonary nodules was limited. To examine potential associations of exposures to PM2.5 and its major chemical constituents with the prevalence of pulmonary nodules. A total of 16 865 participants were investigated from eight physical examination centers in China from 2014 to 2017. The daily concentrations of PM2.5 and its five components were estimated by high-resolution and high-quality spatiotemporal datasets of ground-level air pollutants in China. The logistic regression and the quantile-based g-computation models were used to assess the single and mixture impact of air pollutant PM2.5 and its components on the risk of pulmonary nodules, respectively. Each 1 mg m−3 increase in PM2.5 (OR 1.011 (95% CI: 1.007–1.014)) was positively associated with pulmonary nodules. Among five PM2.5 components, in single-pollutant effect models, every 1 μg m−3 increase in organic matter (OM), black carbon (BC), and NO3
− elevated the risk of pulmonary nodule prevalence by 1.040 (95% CI: 1.025–1.055), 1.314 (95% CI: 1.209–1.407) and 1.021 (95% CI: 1.007–1.035) fold, respectively. In mixture-pollutant effect models, the joint effect of every quintile increase in PM2.5 components was 1.076 (95% CI: 1.023–1.133) fold. Notably, NO3
− BC and OM contributed higher risks of pulmonary nodules than other PM2.5 components. And the NO3
− particles were identified to have the highest contribution. The impacts of PM2.5 components on pulmonary nodules were consistent across gender and age.These findings provide important evidence for the positive correlation between exposure to PM2.5 and pulmonary nodules in China and identify that NO3
− particles have the highest contribution to the risk.
Reflective Fourier ptychography-based depth-recovery & resolution-enhanced real scene hologram acquisition method
Authors: Qian Xin , Ai Lingyu , Shi Xiao , Dong Yue , Cho Myungjin
Published: April 2023

Recording interference holograms using coherent light is a complex process for real-world objects. Alternatively, holography based on integral imaging with natural illumination is considered an option. However, the field of view (FOV) of this technology is limited by the lenslet array of the integral imaging system. This paper proposes an integral imaging-based hologram recording method via a commercial plenoptic camera to increase the FOV for a conventional II system. Meanwhile, to address the problem of depth non-uniform compression caused by the main lens of the plenoptic camera, this paper proposed a depth recovery method combined with the camera’s metadata parameters for depth retargeting. Finally, we introduce a reflective Fourier-ptychography-based algorithm via an optimum overlap rate to acquire high-performance holograms. Compared to stereotypical integral imaging holography, this method produces a higher resolution reconstruction result. In addition, we conduct three sets of experiments on real scenes whose results also prove the proposed method embodies finer reconstruction results, and depth is recovered up to twice as much as the original outcome.
Optical characteristics of radially-polarised twisted light
Authors: Koksal K , Babiker M , Lembessis V E
Published: April 2023

Recent work has confirmed that radially-polarised optical modes, specifically those endowed with helical wave fronts can now be routinely generated in the laboratory. Here we show that such a paraxial mode carries only an axial total optical angular momentum (AM)

where

ℓ

is the winding number and

is a constant. This mode, however, is shown to have zero spin angular momentum (SAM), so it is endowed only with orbital angular momentum (OAM) and no SAM. The helicity is found to be proportional to

ℓ

, hence this kind of mode displays chirality. When applied to a Laguerre–Gaussian (LG) mode our treatment leads to a total helicity equal to

, where

is the action constant. The factor

(
ℓ

/

|

ℓ

|

)
=
±
1

, depends on the sign, not the magnitude of

ℓ

and so the result holds for any radially-polarised LG mode however large the magnitude of its winding number

ℓ

is. The magnitude of the action constant

and hence the helicity are diminished for all such LG modes of large beam waist w
0.
Propagation-induced changes in non-isotropically correlated vector vortex beams
Authors: Manisha  , Khan Saba N , Joshi Stuti , Senthilkumaran P , Kanseri Bhaskar
Published: April 2023

We study the propagation of non-isotropically correlated vector vortex beams (NCVVBs) through an ABCD optical system. The statistical properties, namely, intensity, state of polarization, degree of polarization (DoP), and degree of coherence (DoC) of these beams are investigated. The terminology non-isotropically correlated is used for electromagnetic Gaussian Schell-model beams, that exhibit the distinguishability of spatial correlations between parallel and orthogonal electric field components. The non-isotropic feature of the correlation widths introduces an azimuthal asymmetry in the intensity, DoP, and DoC distributions. The azimuthal asymmetry in the intensity and DoC distributions become prominent around the focal plane. However, this asymmetry can be clearly observed in DoP distributions even at a very short propagation distance. It is found that the statistical properties of NCVVBs are dependent on both Poincaré–Hopf index (PHI) and the source correlation parameters. The number of beamlets in the intensity distribution is twice the magnitude of the PHI of the input beam. Unlike isotropically correlated vector vortex beams, correlation-induced polarization around the central core of the NCVVB is observed. The DoC distribution exhibits the evolution of correlation singularities in the form of dislocations at the far field plane. These dislocations in the DoC profile under lower correlations depend on the PHI, which provides a feasible approach to measure the index of NCVVBs. This study provides a technique to synthesize beams with structured correlation and polarization features.
Cholesterol- and actin-centered view of the plasma membrane: updating the Singer–Nicolson fluid mosaic model to commemorate its 50th anniversary†
Authors: Kusumi Akihiro , Tsunoyama Taka A. , Tang Bo , Hirosawa Koichiro M. , Morone Nobuhiro , Fujiwara Takahiro K. , Suzuki Kenichi G. N.
Published: April 2023

Two very polarized views exist for understanding the cellular plasma membrane (PM). For some, it is the simple fluid described by the original Singer–Nicolson fluid mosaic model. For others, due to the presence of thousands of molecular species that extensively interact with each other, the PM forms various clusters and domains that are constantly changing and therefore, no simple rules exist that can explain the structure and molecular dynamics of the PM. In this article, we propose that viewing the PM from its two predominant components, cholesterol and actin filaments, provides an excellent and transparent perspective of PM organization, dynamics, and mechanisms for its functions. We focus on the actin-induced membrane compartmentalization and lipid raft domains coexisting in the PM and how they interact with each other to perform PM functions. This view provides an important update of the fluid mosaic model.
What Charges?
Authors: Eidinow Esther
Published: April 2023

This chapter examines in more detail the different possible charges that were brought against Theoris, Ninon, and Phryne, and explores both their coherence and their relevance to the fourth-century Athenian context. The possible charges include murder, ‘magic’ (creating spells or potions), and asebeia. This last term can be translated variously as ‘impiety’ or more broadly as ‘religious offence’, and the graphe asebeias was a procedure with a broad remit, which usually concerned some kind of offence against the gods. The chapter investigates the different kinds of activities that could result in a graphe asebeias, and asks whether any of the charges against these women fits the existing evidence about their trials. Finally, it raises some other factors that may have helped to bring these women to court, including their gender and the need to maintain social order.