bluuebunny/crossref_metadata_2025 huggingface dataset:
Tidal Disruption of Stellar Clusters and the Spatial Distribution of Their Remnants Near the Galactic Center
Authors: Wang 王 Long 龙 , Lin 林 D. N. C. 潮
Published: February 2023

The accretion of massive star clusters via dynamical friction has previously been established to be a likely scenario for the buildup of nuclear stellar clusters (NSCs). A remaining issue is whether strong external tidal perturbation may lead to the severe disruption of loosely bound clusters well before they sink deeply into the center of their host galaxies. We carry out a series of N-body simulations and verify our early idealized analytic models. We show that if the density profile of the host galaxies can be described by a power-law distribution with an index of α < 1, the cluster would be compressed in the radial direction by the external galactic tidal field. In contrast, the galactic tidal perturbation is disruptive in regions with a steep, α > 1, density falloff or in the very center where gravity is dominated by the point-mass potential of supermassive black holes (SMBHs). This sufficient criterion supplements the conventional necessary Roche-lobe-filling condition in determining the preservation versus disintegration of satellite stellar systems. We simulate the disruption of stellar clusters that venture onto nearly circular, modestly, or highly eccentric orbits into the center of galaxies with a range of background density profiles and SMBHs. We obtain the spatial distribution of the stellar cluster remnants. We apply these results to the NSC within a few parsecs from SMBH Sgr A* at the Galactic Center. Recent observations indicate the coexistence of two populations of stars with distinctively separate ages and metallicities. We verify that the subsolar-metallicity population can be the debris of disrupted stellar clusters.
The Art of Measuring Physical Parameters in Galaxies: A Critical Assessment of Spectral Energy Distribution Fitting Techniques
Authors: Pacifici Camilla , Iyer Kartheik G. , Mobasher Bahram , da Cunha Elisabete , Acquaviva Viviana , Burgarella Denis , Calistro Rivera Gabriela , Carnall Adam C. , Chang Yu-Yen , Chartab Nima , Cooke Kevin C. , Fairhurst Ciaran , Kartaltepe Jeyhan , Leja Joel , Małek Katarzyna , Salmon Brett , Torelli Marianna , Vidal-García Alba , Boquien Médéric , Brammer Gabriel G. , Brown Michael J. I. , Capak Peter L. , Chevallard Jacopo , Circosta Chiara , Croton Darren , Davidzon Iary , Dickinson Mark , Duncan Kenneth J. , Faber Sandra M. , Ferguson Harry C. , Fontana Adriano , Guo Yicheng , Haeussler Boris , Hemmati Shoubaneh , Jafariyazani Marziye , Kassin Susan A. , Larson Rebecca L. , Lee Bomee , Mantha Kameswara Bharadwaj , Marchi Francesca , Nayyeri Hooshang , Newman Jeffrey A. , Pandya Viraj , Pforr Janine , Reddy Naveen , Sanders Ryan , Shah Ekta , Shahidi Abtin , Stevans Matthew L. , Triani Dian Puspita , Tyler Krystal D. , Vanderhoof Brittany N. , de la Vega Alexander , Wang Weichen , Weston Madalyn E.
Published: February 2023

The study of galaxy evolution hinges on our ability to interpret multiwavelength galaxy observations in terms of their physical properties. To do this, we rely on spectral energy distribution (SED) models, which allow us to infer physical parameters from spectrophotometric data. In recent years, thanks to wide and deep multiwave band galaxy surveys, the volume of high-quality data have significantly increased. Alongside the increased data, algorithms performing SED fitting have improved, including better modeling prescriptions, newer templates, and more extensive sampling in wavelength space. We present a comprehensive analysis of different SED-fitting codes including their methods and output with the aim of measuring the uncertainties caused by the modeling assumptions. We apply 14 of the most commonly used SED-fitting codes on samples from the CANDELS photometric catalogs at z ∼ 1 and z ∼ 3. We find agreement on the stellar mass, while we observe some discrepancies in the star formation rate (SFR) and dust-attenuation results. To explore the differences and biases among the codes, we explore the impact of the various modeling assumptions as they are set in the codes (e.g., star formation histories, nebular, dust and active galactic nucleus models) on the derived stellar masses, SFRs, and A

V
values. We then assess the difference among the codes on the SFR–stellar mass relation and we measure the contribution to the uncertainties by the modeling choices (i.e., the modeling uncertainties) in stellar mass (∼0.1 dex), SFR (∼0.3 dex), and dust attenuation (∼0.3 mag). Finally, we present some resources summarizing best practices in SED fitting.
Similar Signatures of Coplanar Gas Inflow and Disk Warps in Galactic Gas Kinematic Maps
Authors: Wang Enci , Lilly Simon J.
Published: February 2023

Hydrodynamic simulations suggest that galactic gas disks form when coplanar gas spirals into the inner regions of the disk. We recently presented a simple modified accretion disk model of viscous galactic disks in which star formation is fed by a radial flow of gas. However, little observational evidence has been presented for such inflows, which are expected to be only a few kilometers per second in the central regions of the disk, i.e., within four disk scale lengths, but could reach of order 50–100 km s−1 in the very outer disk. The effects of systematic inflow on the 2D velocity field are examined and it is shown that these are quite similar to those produced by geometric warps of the disks, with twist distortions of both the kinematic major and minor axes. This makes it potentially difficult to distinguish between these in practice. By comparing the handedness of the observed twisting of the kinematic axes and of the spiral arms for a sample of nearby galaxies, we find (assuming that the spiral arms are generally trailing) that the effects of warps are in fact likely to dominate over the effects of radial inflows. However, the common practice of treating these twist distortions of the kinematic major and minor axes as being due only to warps can lead, for galaxies of low-to-intermediate inclinations, to substantial underestimates of any systematic inflow.
Weighing the Darkness. III. How Gaia Could, but Probably Will Not, Astrometrically Detect Free-floating Black Holes
Authors: Andrews Jeff J.
Published: February 2023

The gravitational pull of an unseen companion to a luminous star is well known to cause deviations to the parallax and proper motion of a star. In a previous paper in this series, we argue that the astrometric mission Gaia can identify long-period binaries by precisely measuring these arcs. An arc in a star’s path can also be caused by a flyby: a hyperbolic encounter with another massive object. We quantify the apparent acceleration over time induced by a companion star as a function of the impact parameter, velocity of interaction, and companion mass. In principle, Gaia could be used to astrometrically identify the contribution of massive compact halo objects to the local dark matter potential of the Milky Way. However, after quantifying their rate and Gaia’s sensitivity, we find that flybys are so rare that Gaia will probably never observe one. Therefore, every star in the Gaia database exhibiting astrometric acceleration is likely in a long-period binary with another object. Nevertheless, we show how intermediate-mass black holes, if they exist in the local stellar neighborhood, can induce anomalously large accelerations on stars.
Quantifying the Agyrotropy of Proton and Electron Heating in Turbulent Plasmas
Authors: Yang Yan , Pecora Francesco , Matthaeus William H. , Roy Sohom , Cuesta Manuel Enrique , Chasapis Alexandros , Parashar Tulasi , Bandyopadhyay Riddhi , Gershman D. J. , Giles B. L. , Burch J. L.
Published: February 2023

An important aspect of energy dissipation in weakly collisional plasmas is that of energy partitioning between different species (e.g., protons and electrons) and between different energy channels. Here we analyse pressure–strain interaction to quantify the fractions of isotropic compressive, gyrotropic, and nongyrotropic heating for each species. An analysis of kinetic turbulence simulations is compared and contrasted with corresponding observational results from Magnetospheric Multiscale Mission data in the magnetosheath. In assessing how protons and electrons respond to different ingredients of the pressure–strain interaction, we find that compressive heating is stronger than incompressive heating in the magnetosheath for both electrons and protons, while incompressive heating is stronger in kinetic plasma turbulence simulations. Concerning incompressive heating, the gyrotropic contribution for electrons is dominant over the nongyrotropic contribution, while for protons nongyrotropic heating is enhanced in both simulations and observations. Variations with plasma β are also discussed, and protons tend to gain more heating with increasing β.
Exploring Magnetic Loops and Serpentine Fields in the Quiet Sun with the GRIS-IFU
Authors: Campbell Ryan J. , Gafeira Ricardo , Mathioudakis Mihalis , Noda C. Quintero , Collados Manuel
Published: February 2023

Synthetic observations produced from radiative magnetohydrodynamic simulations have predicted that higher polarization fractions in the quiet solar photosphere would be revealed by increasing the total integration time of observations at GREGOR resolutions. We present recently acquired disk center observations of the Fe i 15648.5 Å line obtained with the GREGOR telescope equipped with the GRIS-IFU during excellent seeing conditions, showing exceptionally high polarization fractions. Our observations reveal an internetwork region with a majority (>60%) of magnetized pixels displaying a clear transverse component of the magnetic field. This result is in stark contrast to previous disk center GRIS-IFU observations in this spectral line, which had predominantly vertical magnetic fields in the deep photosphere. At the same time, the median magnetic field strength is weaker than previous GRIS-IFU observations, indicating that the larger fraction of polarization signals cannot be explained by a more active target. We use the Stokes Inversion based on Response functions (SIR) code to analyze the data, performing over 45 million inversions, and interrogate the impact of two conflicting approaches to the treatment of noise on the retrieval of the magnetic inclination and azimuth. We present several case studies of the zoo of magnetic features present in these data, including small-scale magnetic loops that seem to be embedded in a sea of magnetism, and serpentine fields, focusing on regions where full-vector spectropolarimetry has been achieved. We also present a new open-source Python 3 analysis tool, SIR Explorer, which we use to examine the dynamics of these small-scale magnetic features.
Data-driven Cosmology from Three-dimensional Light Cones
Authors: Cheng Yun-Ting , Wandelt Benjamin D. , Chang Tzu-Ching , Doré Olivier
Published: February 2023

We present a data-driven technique to analyze multifrequency images from upcoming cosmological surveys mapping large sky area. Using full information from the data at the two-point level, our method can simultaneously constrain the large-scale structure (LSS), the spectra and redshift distribution of emitting sources, and the noise in the observed data without any prior assumptions beyond the homogeneity and isotropy of cosmological perturbations. In particular, the method does not rely on source detection or photometric or spectroscopic redshift estimates. Here, we present the formalism and demonstrate our technique with a mock observation from nine optical and near-infrared photometric bands. Our method can recover the input signal and noise without bias, and quantify the uncertainty on the constraints. Our technique provides a flexible framework to analyze the LSS observation traced by different types of sources, which has potential for wide application to current or future cosmological data sets such as SPHEREx, Rubin Observatory, Euclid, or the Nancy Grace Roman Space Telescope.
Effect of Multiple Scattering on the Transmission Spectra and the Polarization Phase Curves for Earth-like Exoplanets
Authors: Singla Manika , Chakrabarty Aritra , Sengupta Sujan
Published: February 2023

It is the most appropriate time to characterize the Earth-like exoplanets in order to detect biosignature beyond the Earth because such exoplanets will be the prime targets of big-budget missions like JWST, Roman Space Telescope, HabEx, LUVOIR, Thirty Meter Telescope, Extremely Large Telescope, etc. We provide models for the transmission spectra of Earth-like exoplanets by incorporating the effects of multiple scattering. For this purpose we numerically solve the full multiple-scattering radiative transfer equations instead of using Beer–Bouguer–Lambert’s law, which does not include the diffuse radiation due to scattering. Our models demonstrate that the effect of this diffuse transmission radiation can be observationally significant, especially in the presence of clouds. We also calculate the reflection spectra and polarization phase curves of Earth-like exoplanets by considering both cloud-free and cloudy atmospheres. We solve the 3D vector radiative transfer equations numerically and calculate the phase curves of albedo and disk-integrated polarization by using appropriate scattering phase matrices and integrating the local Stokes vectors over the illuminated part of the disks along the line of sight. We present the effects of the globally averaged surface albedo on the reflection spectra and phase curves as the surface features of such planets are known to significantly dictate the nature of these observational quantities. Synergic observations of the spectra and phase curves will certainly prove to be useful in extracting more information and reducing the degeneracy among the estimated parameters of terrestrial exoplanets. Thus, our models will play a pivotal role in driving future observations.
Center-to-limb Variation of Transition-region Doppler Shifts in Active Regions
Authors: Rajhans Abhishek , Tripathi Durgesh , Kashyap Vinay L. , Klimchuk James A. , Ghosh Avyarthana
Published: February 2023

Studying Doppler shifts provides deep insights into the flow of mass and energy in the solar atmosphere. We perform a comprehensive measurement of Doppler shifts in the transition region and its center-to-limb variation (CLV) in the strong-field regions (∣
B
∣ ≥ 50 G) of 50 active regions (ARs), using the Si iv 1394 Å line recorded by the Interface Region Imaging Spectrometer. To locate the ARs and identify strong-field regions, we have used the magnetograms obtained by the Helioseismic and Magnetic Imager (HMI). We find that in strong-field regions, on average, all the ARs show a mean redshift ranging between 4 and 11 km s−1, which varies with ARs. These flows show a mild CLV, with sizable magnitudes at the limb and substantial scatter in the mid-longitude range. Our observations do not support the idea that redshifts in the lower transition region (T ≲ 0.1 MK) are produced by field-aligned downflows as a result of impulsive heating and they warrant an alternative interpretation, such as a downflow of type-II spicules in the presence of a chromospheric wall created by cooler type-I spicules.
Coronal Densities, Temperatures, and Abundances during the 2019 Total Solar Eclipse: The Role of Multiwavelength Observations in Coronal Plasma Characterization
Authors: Del Zanna Giulio , Samra Jenna , Monaghan Austin , Madsen Chad , Bryans Paul , DeLuca Edward , Mason Helen , Berkey Ben , de Wijn Alfred , Rivera Yeimy J.
Published: February 2023

The Airborne Infrared Spectrometer (AIR-Spec) offers an unprecedented opportunity to explore the near-infrared (NIR) wavelength range. It has been flown at two total solar eclipses, in 2017 and 2019. The wavelength range of the much-improved instrument on the second flight (2019 July 2) was shifted to cover two density-sensitive lines from S xi. In this paper we study detailed diagnostics for temperature, electron density, and elemental abundances by comparing results from AIR-Spec slit positions above the east and west limbs with those from Hinode/EIS, the PolarCam detector, and SDO/AIA. We find very good agreement in the electron densities obtained from the EIS EUV line ratios, those from the NIR S xi ratio, and those obtained from the polarized brightness PolarCam measurements. Electron densities ranged from log N
e [cm−3] = 8.4 near the limb to 7.2 at R
0 = 1.3. EIS spectra indicate that the temperature distribution above the west limb is near isothermal at around 1.3 MK, while that on the east has an additional higher-T component. The AIR-Spec radiances in Si x and S xi, as well as the AIA data in the 171, 193, and 211 Å bands, are consistent with the EIS results. EIS and AIR-Spec data indicate that the sulfur abundance (relative to silicon) is photospheric in both regions, confirming our previous results of the 2017 eclipse. The AIA data also indicate that the absolute iron abundance is photospheric. Our analysis confirms the importance of the diagnostic potential of the NIR wavelength range and that this important wavelength range can be used reliably and independently to determine coronal plasma parameters.
Hydrodynamical Simulations of Black Hole Binary Formation in AGN Disks
Authors: Li Jiaru , Dempsey Adam M. , Li Hui , Lai Dong , Li Shengtai
Published: February 2023

We study close encounters between two single black holes (BHs) embedded in an AGN disk using a series of global 2D hydrodynamics simulations. We find that when the disk density is sufficiently high, bound BH binaries can be formed by the collision of their circum-single disks. Our analysis demonstrates that, after a BH pair passes the pericenter of their relative trajectory, post-collision gas drag may slow down the BHs, possibly forcing the two BHs to stay tightly bound. A binary formed by a close encounter can have a compact semimajor axis, large eccentricity, and retrograde orbital angular momentum. We provide a fitting formula that can accurately predict whether a close encounter can form a binary based on the gas mass and the incoming energy of the encounter. This fitting formula can be easily implemented in other long-term simulations that study the dynamical evolution of BHs in active galactic nucleus disks.
NEID Reveals That the Young Warm Neptune TOI-2076 b Has a Low Obliquity
Authors: Frazier Robert C. , Stefánsson Gudmundur , Mahadevan Suvrath , Yee Samuel W. , Cañas Caleb I. , Winn Joshua N. , Luhn Jacob , Dai Fei , Doyle Lauren , Cegla Heather , Kanodia Shubham , Robertson Paul , Wisniewski John , Bender Chad F. , Dong Jiayin , Gupta Arvind F. , Halverson Samuel , Hawley Suzanne , Hebb Leslie , Holcomb Rae , Kowalski Adam , Libby-Roberts Jessica , Lin Andrea S. J. , McElwain Michael W. , Ninan Joe P. , Petrovich Cristobal , Roy Arpita , Schwab Christian , Terrien Ryan C. , Wright Jason T.
Published: February 2023

TOI-2076 b is a sub-Neptune-sized planet (R = 2.39 ± 0.10 R
⊕) that transits a young (204 ± 50 MYr) bright (V = 9.2) K-dwarf hosting a system of three transiting planets. Using spectroscopic observations obtained with the NEID spectrograph on the WIYN 3.5 m Telescope, we model the Rossiter–McLaughlin effect of TOI-2076 b, and derive a sky-projected obliquity of

λ
=
−

3

−
15

+
16
°

. Using the size of the star (R = 0.775 ± 0.015 R
⊙), and the stellar rotation period (P
rot = 7.27 ± 0.23 days), we estimate an obliquity of

ψ
=

18

−
9

+
10
°

(ψ < 34° at 95% confidence), demonstrating that TOI-2076 b is in a well-aligned orbit. Simultaneous diffuser-assisted photometry from the 3.5 m telescope at Apache Point Observatory rules out flares during the transit. TOI-2076 b joins a small but growing sample of young planets in compact multi-planet systems with well-aligned orbits, and is the fourth planet with an age ≲300 Myr in a multi-transiting system with an obliquity measurement. The low obliquity of TOI-2076 b and the presence of transit timing variations in the system suggest the TOI-2076 system likely formed via convergent disk migration in an initially well-aligned disk.
Records of common species of amphibians and reptiles widespread in northern, central, western and southern Ukraine
Authors: Nekrasova Oksana , Marushchak Oleksii
Published: February 2023

The dataset includes records of amphibian and reptile species from northern, central, western and southern Ukraine made by Ukrainian herpetologist O. D. Nekrasova during her field trips in the period from 1996 to 2022. Chosen species were not included in the latest published edition of the Red Data Book of Ukraine (2009) and in the latest lists of such species prepared in 2019. The species mentioned in this dataset are characterised by wide range within the country, covering more than 70% of its territory according to spatial distribution modelling (GIS-modelling) made with the help of Maxent software.

The dataset highlights records of eight common species of herpetofauna of Ukraine collected by the first author for the last 26 years. Within the period from 1996 to 2022, O. D. Nekrasova collected and studied information and material on the herpetofauna of the northern, central, western and southern parts of Ukraine from a total of 3960 cadastral points (1707 - for three species of reptiles and 2253 - for five species of amphibians). These records, being now available for the international scientific community, will fill the gap in updated records of the mentioned species, being potentially useful for GIS-modelling, distribution modelling, clarification of conservation lists of national and local importance, further assessment of impact of the war on native biota etc.
Les activités de raquette : tout(es) une histoire
Authors: Bauer Thomas , Gomet Doriane , Vaucelle Serge
Published: February 2023

Résumé : Consacré à la genèse et à l’évolution des sports de raquette, cet article poursuit un double projet : offrir des clés de lecture pour mieux appréhender l’essence de cette famille sportive et identifier les travaux scientifiques qui lui ont été consacrés, afin de dégager des pistes de réflexion. S’appuyant à la fois sur une historiographie des pratiques physiques, une archéologie des jeux de raquette et une fresque chronologique de quatre disciplines sous-tendues par des logiques singulières (tennis, tennis de table, badminton, squash), il montre que la « carte génétique » de ces activités comprend trois principales caractéristiques : leur origine paumière, leur forte proximité avec la culture sportive anglaise et la préservation d’un héritage courtois et mondain. Dès lors, l’analyse des principales productions académiques ou fédérales permet de constater, outre le foisonnement récent de travaux en la matière, un élargissement à de nouvelles activités et une diversification des angles de recherche ou cadres théoriques.
Une démocratisation (in)complète ? Premiers éléments d’une sociologie du tennis « féminin » français
Authors: Fontaine Marine
Published: February 2023

À partir d’une enquête par questionnaire menée auprès de 5 293 joueuses françaises classées, cet article analyse le recrutement social du tennis « féminin » et la diversité des pratiques qui caractérisent les catégories officielles de classement de la Fédération Française de Tennis. Nos résultats montrent que le tennis s’est effectivement ouvert aux membres des classes moyennes et populaires, mais cette démocratisation de la pratique dans les catégories officielles « de loisir » ne doit pas masquer les disparités sociales observées lorsque l’on monte dans la hiérarchie du classement. Les conditions de pratique, de formation et de carrière des tenniswomen demeurent des freins à une pleine démocratisation du tennis. Une démocratisation encore inachevée qui est lourde d’enjeux si l’on considère le fait que, malgré la constante progression des licences « féminines » dans les activités sportives, le taux de féminisation du tennis ne cesse de diminuer (35 % en 2000 ; 29,4 % en 2019).
L’enseignement de la littérature. Les leçons d’une crise
Authors: Kerlan Alain
Published: February 2023

En 2007, Tzvetan Todorov, éminent linguiste et l’un des phares de cette modernité structuraliste dont l’influence sur l’enseignement scolaire de la langue et de la littérature a été décisive et longtemps en règne, publiait un essai, La littérature en péril , remettant profondément en cause cette domination et ses conséquences dans l’enseignement. Il y donnait raison au lecteur cherchant dans les œuvres de quoi donner sens à son existence, contre le primat accordé à la textualité. En 2011, Jean-Marie Schaeffer, dans sa Petite écologie des études littéraires , s’inscrivait aussi dans cette lignée et tirait également la leçon des impasses et des conséquences de la réduction moderniste de la littérature et de son enseignement. Prenant acte de la crise des études littéraires, l’auteur estime qu’elle nécessite d’en passer par l’analyse des fondements de notre rapport au monde, et de la littérature comme accès à un mode d’expérience spécifique. Comme le voulait Hannah Arendt, toute crise donne l’occasion de se saisir de l’essence d’un problème. La crise de l’enseignement littéraire met au jour les conséquences de l’entrée de la littérature en régime esthétique, et plus largement révèle la nécessité de repenser la littérature et de l’enseigner comme une modalité spécifique de l’expérience esthétique.
Penser le mal potentiel de la relation humaine à partir des contes traditionnels
Authors: Hétier Renaud
Published: February 2023

La relation éducative a beaucoup évolué dans le temps, notamment depuis quelques décennies. La dureté des parents, la méchanceté présumée des enfants, cela semble être tombé en désuétude dans notre modernité avancée. Pourtant, il est bien possible que nous n’en ayons pas fini avec le mal dans la relation humaine, y compris dans les relations de grande proximité, comme la relation parent / enfant. Ce mal ne relève pas forcément d’un passage à l’acte, mais d’une propension à se nourrir de l’autre, voire de le parasiter. La culture peut aider les enfants à sentir, mettre en forme, penser cela. Or, si les contes traditionnels mettent effectivement ce problème du mal au cœur de la relation éducative elle-même, la modernité (dans la littérature de jeunesse, notamment) occulte ce mal, voire le renverse (les figures autrefois menaçantes deviennent elles-mêmes vulnérables, elles sont en demande d’amour et ce sont leurs anciennes victimes (les enfants) qui sont méchantes).
Dynamics of a delayed diffusive predator-prey model with Allee effect and nonlocal competition in prey and hunting cooperation in predator
Authors: Xiang Yujia , Jiao Yuqi , Wang Xin , Yang Ruizhi
Published: February 2023

In this paper, a delayed diffusive predator-prey model with the Allee effect and nonlocal competition in prey and hunting cooperation in predators is proposed. The local stability of coexisting equilibrium and the existence of Hopf bifurcation are studied by analyzing the eigenvalue spectrum. The property of Hopf bifurcation is also studied by the center manifold theorem and normal form method. Through numerical simulation, the analysis results are verified, and the influence of these parameters on the model is also obtained. Firstly, increasing the Allee effect parameter $ \beta $ and hunting cooperation parameter $ \alpha $ is not conducive to the stability of the coexistence equilibrium point under some parameters. Secondly, the time delay can also affect the stability of coexisting equilibrium and induce periodic solutions. Thirdly, the nonlocal competition in prey can affect the dynamic properties of the predator-prey model and induce new dynamic phenomena (stably spatially inhomogeneous bifurcating periodic solutions).
Platoon-based collision-free control for connected and automated vehicles at non-signalized intersections
Authors: Gong Jian , Zhao Yuan , Cao Jinde , Huang Wei
Published: February 2023

This paper proposes a distributed collision-free control scheme for connected and automated vehicles (CAVs) at a non-signalized intersection. We first divide an intersection area into three sections, i.e., the free zone, the platoon zone, and the control zone. In order to enable the following vehicles to track the trajectory of their leading vehicle in the platoon zone and the control zone, as well as to guarantee the desired distance between any two adjacent vehicles, the distributed platoon controllers are designed. In the control zone, each vehicular platoon is taken as a whole to be coordinated via an intersection coordination unit (ICU). To avoid collision between each pair of the conflicting platoons approaching from different directions, a platoon-based coordination strategy is designed by scheduling the arrival time of each leading vehicle of different platoons. Specially, considering traffic efficiency and fuel economy, the optimal control problem of the leading vehicle is formulated subject to the constraint of allowable minimum arrival time, which is derived from coordination with other approaching platoons. The Pontryagin Minimum Principle (PMP) and phase-plane method are applied to find the optimal control sequences. Numerical simulations show the effectiveness of this scheme.
A novel class of forward-backward explicit iterative algorithms using inertial techniques to solve variational inequality problems with quasi-monotone operators
Authors: Panyanak Bancha , Khunpanuk Chainarong , Pholasa Nattawut , Pakkaranang Nuttapol
Published: February 2023

The theory of variational inequalities is an important tool in physics, engineering, finance, and optimization theory. The projection algorithm and its variants are useful tools for determining the approximate solution to the variational inequality problem. This paper introduces three distinct extragradient algorithms for dealing with variational inequality problems involving quasi-monotone and semistrictly quasi-monotone operators in infinite-dimensional real Hilbert spaces. This problem is a general mathematical model that incorporates a set of applied mathematical models as an example, such as equilibrium models, optimization problems, fixed point problems, saddle point problems, and Nash equilibrium point problems. The proposed algorithms employ both fixed and variable stepsize rules that are iteratively transformed based on previous iterations. These algorithms are based on the fact that no prior knowledge of the Lipschitz constant or any line-search framework is required. To demonstrate the convergence of the proposed algorithms, some simple conditions are used. Numerous experiments have been conducted to highlight the numerical capabilities of algorithms.
Modeling the impact of public health education on tungiasis dynamics with saturated treatment: Insight through the Caputo fractional derivative
Authors: Simelane Simphiwe M. , Dlamini Phumlani G. , Osaye Fadekemi J. , Obaido George , Ogbukiri Blessing , Aruleba Kehinde , Jones Cadavious M. , Chukwu Chidozie W. , Egbelowo Oluwaseun F.
Published: February 2023

Public health education is pivotal in the management and control of infectious and non-infectious diseases. This manuscript presents and analyses a nonlinear fractional model of tungiasis dynamics with the impact of public health education for the first time. The human population is split into five classes depending on their disease status. The infected population is split into two subgroups; infected but unaware and infected but aware. The model focuses on the impacts of public health education, contact and treatment contact on tungiasis transmission dynamics. Notably, public health education is important for containing as well as reducing disease outbreaks in communities. The Caputo fractional derivative is utilised in defining the model governing equations. Model equilibrium points existence and stability are investigated using simple matrix algebra. Model analysis shows that tungiasis is contained when the reproduction number is less than unity. Otherwise, if it is greater than unity, the disease persists and spread in the population. The generalised Adams-Bashforth-Moulton approach is utilised in solving the derived tungiasis model numerically. The impacts of public health education, treatment and contact rate on overall disease dynamics are discussed through numerical simulations. From the simulations, we see that for given fractional order, public health education and treatment increase the quality of life plus reduce equilibrium numbers of tungiasis-infected individuals. We observe that population classes converge quicker to their steady states when $ \alpha $ is increased. Thus, we can conclude that the derivative order $ \alpha $ captures the role of experience or knowledge that individuals have on the disease's history.
Improved YOLOv5s model for key components detection of power transmission lines
Authors: Chen Chen , Yuan Guowu , Zhou Hao , Ma Yi
Published: February 2023

High-voltage transmission lines are located far from the road, resulting in inconvenient inspection work and rising maintenance costs. Intelligent inspection of power transmission lines has become increasingly important. However, subsequent intelligent inspection relies on accurately detecting various key components. Due to the low detection accuracy of key components in transmission line image inspection, this paper proposed an improved object detection model based on the YOLOv5s (You Only Look Once Version 5 Small) model to improve the detection accuracy of key components of transmission lines. According to the characteristics of the power grid inspection image, we first modify the distance measurement in the k-means clustering to improve the anchor matching of the YOLOv5s model. Then, we add the convolutional block attention module (CBAM) attention mechanism to the backbone network to improve accuracy. Finally, we apply the focal loss function to reduce the impact of class imbalance. Our improved method's mAP (mean average precision) reached 98.1%, the precision reached 97.5%, the recall reached 94.4% and the detection rate reached 84.8 FPS (frames per second). The experimental results show that our improved model improves the detection accuracy and has advantages over other models in performance.
Determinants of tuberculosis treatment support costs to the treatment supporters in rural Ghana
Authors: Bio Robert Bagngmen , Akweongo Patricia , Adomah-Afari Augustine , Koduah Augustina
Published: February 2023

Background

The Ghana Health Service has been implementing the Directly Observed Therapy Short Course (DOTS) strategy for decades now, to cure and reduce the transmission of tuberculosis. DOTS strategy requires TB patients and their treatment supporters to make multiple clinic visits in the course of treatment, and this may place financial burden on treatment supporters with low socio-economic status. However, the determinants of tuberculosis treatment support costs to treatment supporters are unknown in Ghana.

Objectives

This study determined the costs associated with treatment support to the treatment supporters in Bono Region, Ghana.

Methods

In a cross-sectional study using cost-of-illness approach, 385 treatment supporters were selected and interviewed. A validated questionnaire for the direct and indirect costs incurred was used. Descriptive statistics and bivariate techniques were used for data analysis.

Results

Averagely, each treatment supporter spent GHS 122.4 (US$ 21.1) on treatment support activities per month, which is about 19% of their monthly income. The findings also revealed that highest level of education, household size, monthly income and district of residence were significant predictors of the direct costs. On the other hand, gender of the respondents, highest level of education, ethnicity, household size, income level and relationship with patient were some of the factors that significantly influenced the indirect costs. The significance levels were set at a 95% confidence interval and p < 0.05.

Conclusion

The study concludes that the estimated cost associated with assisting tuberculosis patients with treatment is significant to treatment supporters. If these costs are not mitigated, they have the tendency of affecting the socio-economic status and welfare of individuals assisting tuberculosis patients with treatment.
Colonialism, Migration and the Emergence of Urban Spaces in Colonial Nigeria
Authors: Adesola Adesote Samson , Olabiyi Osiyale Babatunde
Published: February 2023

Arguably, urbanisation, which entails spatial, social, and temporal phenomena, is a social process describing how cities grow and societies become more complex. From this point of view, urbanisation is not a new phenomenon in Nigeria in particular and Africa in general. The process of urbanisation in Nigeria began in the pre-colonial period and continued during the colonial and post-colonial periods. However, the factors or conditions that facilitated urbanisation in each historical epoch of urbanisation in Nigeria have changed over time. This paper interrogates the effect of colonialism on the emergence of urban spaces in Nigeria between 1900 and 1960. It argues that migration, which constituted one of the main drivers of the emergence of urban spaces in Nigeria during this period, was promoted by the introduction of the British colonial policy of the administration. The main trend of internal migration during colonial Nigeria examined in the paper involves a drift from the rural areas and the lesser towns to the new urban centres of commerce and administration which developed in response to the establishment of formal colonial rule. This trend of internal migration was witnessed in different parts of Nigeria such as Lagos, Ibadan, Ogbomoso, Osogbo, Benin City (all in Western Nigeria); Onitsha, Enugu, Calabar, Port Harcourt (all in Eastern Nigeria); Kano, Jos, Makurdi, Zaria, Sokoto and Kaduna (all in Northern Nigeria) between 1900 and 1960. It concludes that the physical spaces in these cities have had a fundamental significance for the host communities, migrants and for host/migrant relations.
Isobaric Tag for Relative and Absolute Quantitation-Based Proteomics for Investigating the Effect of Guasha on Lumbar Disc Herniation in Rats
Authors: Yang Min , Xu Gui-Hua
Published: February 2023

Objective:

The objective of the study is to examine the possible mechanism by which Guasha (scraping therapy) affects the expression profiles of proteins in a lumbar disc herniation (LDH) rat model using isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics.

Methods:

Thirty-six rats were used in this study. LDH rats were subjected to noncompressive LDH surgeries. Rats were randomly divided into the model and Guasha groups. Guasha was applied on alternate days for a total of nine times (three courses). At the end of each course, six rats were randomly selected from each group and their blood samples were collected. iTRAQ labeling was used to examine the mechanism of action of Guasha against LDH. The molecular functions, cellular components, and biological processes were analyzed using gene ontology analysis. The Ingenuity Pathway Analysis database was used to identify canonical pathways involving these proteins.

Results:

Compared to the model group, 198, 182, and 170 proteins were identified as differentially expressed at the three respective Guasha treatment courses. Pathways, including focal adhesion kinase signaling, acute-phase response signaling, and the LXR/RXR activation pathway, were closely related to the effects of Guasha in LDH rats. Furthermore, Rac1, Orm1, and Hpx were validated by western blotting, and the results were consistent with the protein expression levels observed using the iTRAQ method.

Conclusion:

Guasha could not only regulate the pathological changes related to LDH, but also achieve therapeutic effects by stimulating physiological changes. Our results offer a better understanding of the effects of Guasha on LDH.
Network Pharmacology-Based and Pharmacological Evaluation of the Effects of Curcumae Radix on Cerebral ischemia–Reperfusion Injury
Authors: Zhang Shang-Xia , Wang Yu-Hong , Long Hong-Ping , Liu Jian , Zhaoa Hong-Qing , Yi Jian , Ling Jia
Published: February 2023

Objective:

This study aimed to investigate the network pharmacology of curcumae radix (CR, Yujin) and explore the mechanism of CR in the treatment of cerebral ischemia–reperfusion injury (CIRI).

Materials and Methods:

Network analysis and pharmacological evaluation were performed to explore the protective role of CR to treat CIRI. The potential target genes of the active components and CIRI were identified using SwissTarget Prediction, Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine, GeneCards, and Online Mendelian Inheritance in Man. Furthermore, network analysis was performed using Cytoscape software. Gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed using the R software. In vivo experiments were performed using the water extract of CR (WECR) on PC12 cells induced by hypoxia/reoxygenation (H/R) to simulate ischemia/reperfusion injury.

Results:

The results exhibited that 21 active compounds identified in CR were associated with 73 targets of CIRI. Functional analysis showed that multiple pathways, including response to stress, regulation of apoptotic process, and hypoxia-inducible factor 1 signaling pathway, were significantly enriched. In addition, STAT3, IL4, HIFIA, and CTNNB1 were predicted to be the most important genes among the 36 hub genes. Furthermore, WECR treatment significantly improved PC12 cell injury and decreased apoptosis levels in cells induced by H/R, with malondialdehyde contents reduced and superoxide dismutase or glutathione peroxidase levels increased.

Conclusions:

Network analysis and pharmacological evaluation of CR could provide valuable directions for further research on CR and improve comprehension of CIRI.
Outcome of perioperative 24-hour infusion of intravenous lignocaine on pain and QoR-15 scores after breast cancer surgery-A randomised controlled trial
Authors: Sethi Dhruv , Ramakrishnan Priya , Khurana Gurjeet K. , Arora Anshika
Published: February 2023

Background and Aims:

Despite many analgesic modalities available, postoperative pain management after breast cancer surgery remains a challenge, which translates into poor quality of recovery, if untreated. Intravenous lignocaine with its anti-inflammatory, antihyperalgesic, and analgesic properties could provide a good option for these patients. The aim of this study was to evaluate the effect of intravenous lignocaine on postoperative pain relief and quality of recovery in patients undergoing surgery for breast cancer.

Methods:

In this prospective double-blind placebo-controlled randomised study, sixty-six patients undergoing breast cancer surgery were assigned 1:1 to placebo or intravenous lignocaine (Group L). Group L received an intravenous 1.5 mg/kg of lignocaine bolus at induction, followed by an intravenous infusion of 1 mg/kg/h for 24 hours intravenously, while the control group was given equal volume of normal saline. Pain scores, opioid utilisation, and quality of recovery (QoR-15) at 24 hours and on the day of suture removal were compared.

Results:

Statistically significant reduction was observed in both static (P = 0.01, 6 hours) and dynamic postoperative pain (P = 0.030, 24 hours), with consequential delay in the need for the first dose of opioid (P = 0.014) as well as decreased 24-hour postoperative opioid consumption (P < 0.001) and decreased post-operative nausea and vomiting (PONV) (P < 0.05) in the lignocaine group. Global QoR-15 was significantly better at 24 -hours in group L on postoperative day 1 (P < 0.001), albeit there was no significant difference at suture removal. No lignocaine related side effects were observed.

Conclusion:

Intravenous lignocaine can be safely used as an alternative perioperative non-opioid analgesic for early postoperative pain and recovery.
Critical Incident Stress Debriefing Experience, Training, and Anticipated Barriers in Emergency Medicine Providers: A Targeted Needs Assessment
Authors: Loke Dana Elizabeth , Dastoor Jehannaz D. , Fant Abra L.
Published: February 2023

Background:

This study was a targeted needs assessment gauging emergency medicine provider training and experience in critical incident stress debriefing (CISD), comfort leading and barriers to real-time CISD, and perceived benefits from CISD training.

Methods:

An electronic survey was administered to 113 emergency medicine providers including residents, advanced practice providers, and attending/fellow physicians. Survey questions included demographic information, indication of prior participation and leading CISD, comfort level in leading CISD, and perceived benefits from CISD training. We used a combination of “yes/no/I do not know” and Likert scale responses. We also used short answers for comments on barriers to real-time CISD. Findings were determined using analysis of variance analyses with statistical significance defined at P < 0.05.

Results:

Survey response rate was 61.9%. Only 48.5% had participated in CISD. Although 24.3% had led CISD, only 18.6% had prior training. Respondents did not feel comfortable leading CISD, although attending physicians felt most comfortable (P < 0.001). Respondents felt they would benefit from and participate in training if offered. Commonly reported barriers to real-time debriefing were lack of time and preoccupation with other patient care.

Conclusions:

Our targeted needs assessment demonstrated a lack of CISD training in emergency medicine providers and discomfort leading CISD. Respondents did perceive training as beneficial and would participate if offered.
Cardioembolic stroke, the most common subtype of stroke in COVID 19: A single center experience from Isfahan, Iran
Authors: Tajmirriahi Marzieh , Esfahani Maryam Masjedi , Amouaghaei Zahra , Mansori Nahid , Miralaei Pantea , Lalehzar Sahar Sadat , Shirani Peiman , Saadatnia Mohammad
Published: February 2023

Background:

Some studies showed the cerebrovascular manifestation in patients with recently pandemic coronavirus 2 named the coronavirus disease 2019 (COVID-19). However, there are rare reports about stroke subtypes in these patients. Here, we reported the stroke subtype in patients with laboratory-confirmed diagnosis of COVID-19 and treated at our hospitals, which are located in Isfahan, Iran.

Materials and Methods:

This is a retrospective, observational case series. Data were collected from March 01, 2020, to May 20, 2020, at three designated special care centers for COVID-19 of Isfahan University of Medical Sciences. The study included 1188 consecutive hospitalized patients with laboratory-confirmed diagnosis of COVID-19.

Results:

Of 1188 COVID-19 patients, 7 (0.5%) patients developed stroke. Five (0.4%) had ischemic arterial stroke, 1 (0.08%) hemorrhagic stroke and 1(0.08 %) cerebral venous and sinus thrombosis. Sixty percent of ischemic stroke were cardioembolic stroke (CE) and the rest 2 (40%) were embolic stroke of undetermined source. Three male patients (40%) had stroke as a presenting and admitted symptom of COVID-19. Four patients (57%) had severe COVID-19.

Conclusion:

Stroke was an uncommon manifestation in COVID-19 patients. CE was a common subtype of stroke in COVID-19 patients in our centers.