bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptional activators YAP/TAZ and AXL orchestrate dedifferentiation, cell fate, and metastasis in human osteosarcoma
Authors: Lamhamedi-Cherradi Salah-Eddine , Mohiuddin Sana , Mishra Dhruva K. , Krishnan Sandhya , Velasco Alejandra Ruiz , Vetter Amelia M. , Pence Kristi , McCall David , Truong Danh D. , Cuglievan Branko , Menegaz Brian A. , Utama Budi , Daw Najat C. , Molina Eric R. , Zielinski Rafal J. , Livingston John A. , Gorlick Richard , Mikos Antonios G. , Kim Min P. , Ludwig Joseph A.
Published: January 2021

Osteosarcoma (OS) is a molecularly heterogeneous, aggressive, poorly differentiated pediatric bone cancer that frequently spreads to the lung. Relatively little is known about phenotypic and epigenetic changes that promote lung metastases. To identify key drivers of metastasis, we studied human CCH-OS-D OS cells within a previously described rat acellular lung (ACL) model that preserves the native lung architecture, extracellular matrix, and capillary network. This system identified a subset of cells—termed derived circulating tumor cells (dCTCs)—that can migrate, intravasate, and spread within a bioreactor-perfused capillary network. Remarkably, dCTCs highly expressed epithelial-to-mesenchymal transition (EMT)-associated transcription factors (EMT-TFs), such as ZEB1, TWIST, and SOX9, which suggests that they undergo cellular reprogramming toward a less differentiated state by coopting the same epigenetic machinery used by carcinomas. Since YAP/TAZ and AXL tightly regulate the fate and plasticity of normal mesenchymal cells in response to microenvironmental cues, we explored whether these proteins contributed to OS metastatic potential using an isogenic pair of human OS cell lines that differ in AXL expression. We show that AXL inhibition significantly reduced the number of MG63.2 pulmonary metastases in murine models. Collectively, we present a laboratory-based method to detect and characterize a pure population of dCTCs, which provides a unique opportunity to study how OS cell fate and differentiation contributes to metastatic potential. Though the important step of clinical validation remains, our identification of AXL, ZEB1, and TWIST upregulation raises the tantalizing prospect that EMT-TF-directed therapies might expand the arsenal of therapies used to combat advanced-stage OS.
Efficient IL-2R signaling differentially affects the stability, function, and composition of the regulatory T-cell pool
Authors: Permanyer Marc , Bošnjak Berislav , Glage Silke , Friedrichsen Michaela , Floess Stefan , Huehn Jochen , Patzer Gwendolyn E. , Odak Ivan , Eckert Nadine , Zargari Razieh , Ospina-Quintero Laura , Georgiev Hristo , Förster Reinhold
Published: January 2021

Signaling via interleukin-2 receptor (IL-2R) is a requisite for regulatory T (Treg) cell identity and function. However, it is not completely understood to what degree IL-2R signaling is required for Treg cell homeostasis, lineage stability and function in both resting and inflammatory conditions. Here, we characterized a spontaneous mutant mouse strain endowed with a hypomorphic Tyr129His variant of CD25, the α-chain of IL-2R, which resulted in diminished receptor expression and reduced IL-2R signaling. Under noninflammatory conditions, Cd25Y129H mice harbored substantially lower numbers of peripheral Treg cells with stable Foxp3 expression that prevented the development of spontaneous autoimmune disease. In contrast, Cd25Y129H Treg cells failed to efficiently induce immune suppression and lost lineage commitment in a T-cell transfer colitis model, indicating that unimpaired IL-2R signaling is critical for Treg cell function in inflammatory environments. Moreover, single-cell RNA sequencing of Treg cells revealed that impaired IL-2R signaling profoundly affected the balance of central and effector Treg cell subsets. Thus, partial loss of IL-2R signaling differentially interferes with the maintenance, heterogeneity, and suppressive function of the Treg cell pool.
Daily supplementation with the Lab4P probiotic consortium induces significant weight loss in overweight adults
Authors: Michael D. R. , Davies T. S. , Jack A. A. , Masetti G. , Marchesi J. R. , Wang D. , Mullish B. H. , Plummer S. F.
Published: January 2021

This 9-month randomised, parallel, double-blind, single-centre, placebo-controlled study (PROBE, ISRCTN18030882) assessed the impact of probiotic supplementation on bodyweight. Seventy overweight Bulgarian participants aged 45–65 years with BMI 25–29.9 kg/m2 received a daily dose of the Lab4P probiotic comprising lactobacilli and bifidobacteria (50 billion cfu/day). Participants maintained their normal diet and lifestyle over the duration of the study. The primary outcome was change from baseline in body weight and secondary outcomes included changes in waist circumference, hip circumference and blood pressure. A significant between group decrease in body weight (3.16 kg, 95% CI 3.94, 2.38, p < 0.0001) was detected favouring the probiotic group. Supplementation also resulted in significant between group decreases in waist circumference (2.58 cm, 95% CI 3.23, 1.94, p < 0.0001) and hip circumference (2.66 cm, 95% CI 3.28, 2.05, p < 0.0001) but no changes in blood pressure were observed. These findings support the outcomes of a previous shorter-term Lab4P intervention study in overweight and obese participants (PROMAGEN, ISRCTN12562026). We conclude that Lab4P has consistent weight modulation capability in free-living overweight adults.
Advances in gold nanoparticles for mycotoxin analysis
Authors: Wu Linxia , Wang Meng , Wei Dizhe
Published: January 2021

AuNPs have been widely used in mycotoxin detection including ELISA, optical-based sensors, electrochemical-based sensors, surface-enhanced Raman scattering-based sensors, mass-based sensors and other sensors.
Rapid detection of Klebsiella pneumoniae producing extended spectrum β lactamase enzymes by infrared microspectroscopy and machine learning algorithms
Authors: Suleiman Manal , Abu-Aqil George , Sharaha Uraib , Riesenberg Klaris , Sagi Orli , Lapidot Itshak , Huleihel Mahmoud , Salman Ahmad
Published: January 2021

FTIR spectroscopy of Klebsiella pneumoniae in tandem with machine learning enables detection of ESBL producing isolates in 20 minutes after first culture, which helps physicians to treat bacterial infected patients appropriately.
Anin silicoinvestigation of the binding modes and pathway of APTO-253 on c-KIT G-quadruplex DNA
Authors: Pal Saikat , Paul Sandip
Published: January 2021

Identification of the top, bottom and side loop binding modes of the APTO-253 ligand on c-KIT G-quadruplex DNA.
Conformational dynamics is critical for the allosteric inhibition of cGAS upon acetyl-mimic mutations
Authors: Guo Jingjing , Li Mengrong , Zhang Yan , Xi Lili , Cui Fengling
Published: January 2021

In the present study, the allosteric inhibition mechanism of cGAS upon acetyl-mimic mutations was investigated, and conformational dynamics was found to be especially critical.
Intramolecular charge transfer excitation induced by CH3O substitution in the 3-methoxy-1-propoxy radical
Authors: Xue Junfei , Qin Tai , Zu Lily
Published: January 2021

The charge-transfer excited state of 3-methoxy-1-propoxy has a conical intersection with the CO excited state, which changes its LIF spectrum.
Hydroxylated BiFeO3 as efficient fillers in poly(vinylidene fluoride) for flexible dielectric, ferroelectric, energy storage and mechanical energy harvesting application
Authors: Sasmal Abhishek , Patra Aniket , Devi P. Sujatha , Sen Shrabanee
Published: January 2021

Hydroxylation of a BiFeO3 filler improved the dielectric permittivity, energy storage density and mechanical energy harvesting performance along with reduced dielectric loss of its PVDF based composites compared to that of an untreated BiFeO3 filler.
Active metal single-sites based on metal–organic frameworks: construction and chemical prospects
Authors: Sun Yiyang , Du Qiuzheng , Wang Fangqi , Dramou Pierre , He Hua
Published: January 2021

Metal single-point is a novel and potential design strategy that has been applied for the development of metal organic frameworks.
Gallium–indium nanoparticles as phase change material additives for tunable thermal fluids
Authors: Mingear Jacob , Farrell Zachary , Hartl Darren , Tabor Christopher
Published: January 2021

Inorganic Ga–In alloy nanoparticles suspended in a traditional thermal transport fluid simultaneously increase the overall thermal diffusivity of the fluid and serve as a cyclable solid–liquid PCM slurry, providing a thermal sink definable over a wide temperature range.
Encapsulation of metal nanoparticles at the surface of a prototypical layered material
Authors: Lii-Rosales Ann , Han Yong , Jing Dapeng , Tringides Michael C. , Julien Scott , Wan Kai-Tak , Wang Cai-Zhuang , Lai King C. , Evans James W. , Thiel Patricia A.
Published: January 2021

Metal nanoclusters encapsulated beneath the graphite surface present novel surface nanostructures and open opportunities to investigate and control interfacial properties.
High-performance flexible resistive random access memory devices based on graphene oxidized with a perpendicular oxidation gradient
Authors: Aziz Tariq , Wei Shijing , Sun Yun , Ma Lai-Peng , Pei Songfeng , Dong Shichao , Ren Wencai , Liu Qi , Cheng Hui-Ming , Sun Dong-Ming
Published: January 2021

Defect-rich graphene oxidized with a perpendicular oxidation gradient is used as the resistive layer to construct the high-performance flexible RRAMs with excellent reliability and reproducibility without the aid of an interfacial redox reaction.
Silicon-rhodamine isothiocyanate for fluorescent labelling
Authors: Nasufović Veselin , Then Patrick , Dröge Fabian , Duong Michael , Kaether Christoph , Dietzek Benjamin , Heintzmann Rainer , Arndt Hans-Dieter
Published: January 2021

An efficient high yielding synthesis for silicon-rhodamines (SiR) led to silicon-rhodamine isothiocyanate (SITC) for facile fluorescent labeling in high-resolution imaging.
Quantifying the link between local structure and cellular rearrangements using information in models of biological tissues
Authors: Tah Indrajit , Sharp Tristan A. , Liu Andrea J. , Sussman Daniel M.
Published: January 2021

A machine-learning classifier predicts impending topological rearrangement in a model of dense tissue, extracting a large fraction of the total available information contained in local structure throughout the model’s parameter space.
A data‐driven measurement placement to evaluate the well‐being of distribution systems operation
Authors: Jafarian Mohammad , Soroudi Alireza , Keane Andrew
Published: January 2021

The widespread integration of intelligent electronic devices has facilitated the employment of data mining methods in evaluating the operating condition of distribution systems. This possibility comes to prominence in active networks, where distributed energy resources can cause unforeseen dynamics that requires an effective monitoring infrastructure and a fast‐track procedure to convey the system operating condition in a comprehensible manner to the operator. To this end, a data‐driven approach is proposed to assess the status of system operating constraints by presenting each constraint as a classification problem. Afterwards, by exploiting the propounded presentation of the system operating condition, the measurement placement problem in distribution systems is addressed as selecting a set of features that have the most contribution to evaluating the system operating status . To do so, first, the effectiveness of the measurement units is identified through their contribution to the classification process, and then a procedure is proposed to pinpoint the measurement units with redundant information. Monte–Carlo simulations are performed to provide a comprehensive training set. Receiver operating characteristic analysis and time‐series power flows demonstrate the effectiveness of the proposed approaches.
Small amount of TiO2 modified SnO2 with enhanced photocatalytic performance toward the removal of rhodamine B
Authors: Zhang Yi , Yang Hu , Zou Wei
Published: January 2021

Tin dioxide (SnO2) photocatalyst has broad prospects for the degradation of toxic organic pollutants; however, its practical application is greatly hampered by poor activity due to the high recombination rates of photogenerated electron‐hole pairs. In this work, titania (TiO2) modified SnO2 photocatalysts were obtained by a facile hydrothermal method to suppress the rapid recombination of photogenerated electron‐hole pairs and improve the photocatalytic activity. Ultraviolet–visible (UV–vis)_ diffuse reflectance spectra suggest that TiO2–SnO2 composite photocatalysts hold stronger UV light absorption ability than that of the pure SnO2. Surface photovoltage spectroscopy and photoelectrochemistry results show that the separation rate of photogenerated charge pairs of TiO2–SnO2 photocatalysts was greatly enhanced. The photocatalytic activities of the photocatalysts were evaluated by the decay of rhodamine B (RhB) under UV irradiation illumination. The results display that modification of SnO2 by TiO2 can largely enhance the photocatalytic activity and the photocatalytic performance of 0.5:1‐TS sample is nearly 5 times that of the pure SnO2. Moreover, maintaining the ratio of TiO2 and SnO2 at 0.5:1, the amount of catalyst was 30 mg, the concentration of dye was 10 mg/l, and the pH of RhB solution was 2, the sample has the best photocatalytic activity.
Impact of non-gravitational effects on chaotic properties of retrograde orbits
Authors: Kankiewicz Paweł , Włodarczyk Ireneusz
Published: January 2021

Context.Dynamical studies of asteroid populations in retrograde orbits, that is with orbital inclinations greater than 90 degrees, are interesting because the origin of such orbits is still unexplained. Generally, the population of retrograde asteroids includes mostly Centaurs and transneptunian objects. A special case is the near-Earth object (343158) 2009 HC82 from the Apollo group. Another interesting object is the comet 333P/LINEAR, which for several years was considered the second retrograde object approaching Earth. Another comet in retrograde orbit, 161P Hartley/IRAS appears to be an object of similar type. Thanks to the large amount of observational data for these two comets, we tested various models of cometary non-gravitational forces applied to their dynamics.

Aims.The goal was to estimate which of non-gravitational perturbations could affect the stability of retrograde bodies. In principle, we study the local stability by measuring the divergence of nearby orbits.

Methods.We numerically determined Lyapunov characteristic indicators and the associated Lyapunov times (LT). This time, our calculations of these parameters were extended by more advanced models of non-gravitational perturbations (i.e. Yarkovsky drift and in selected cases cometary forces). This allowed us to estimate chaos in the Lyapunov sense.

Results.We found that the Yarkovsky effect for obliquities ofγ= 0° andγ= 180° can change the LT substantially. In most cases, for the prograde rotation, we received more stable solutions. Moreover, we confirmed the role of retrograde resonances in this process. Additionally, the studied cometary effects also significantly influence the long-term behaviour of the selected comets. The LT can reach values from 100 to over 1000 yr.

Conclusions.All of our results indicate that the use of models with non-gravitational effects for retrograde bodies is clearly justified.
Phase-space structure of protohalos: Vlasov versus particle-mesh
Authors: Colombi S.
Published: January 2021

The phase-space structure of primordial dark matter halos is revisited using cosmological simulations with three sine waves and cold dark matter (CDM) initial conditions. The simulations are performed with the tessellation based Vlasov solver ColDICE and a particle-mesh (PM) N-body code. The analyses include projected density, phase-space diagrams, radial density ρ(r), and pseudo-phase space density: Q(r) = ρ(r)/σv(r)3 with σv the local velocity dispersion. Particular attention is paid to force and mass resolution. Because the phase-space sheet complexity, estimated in terms of total volume and simplex (tetrahedron) count, increases very quickly, ColDICE can follow only the early violent relaxation phase of halo formation. During the violent relaxation phase, agreement between ColDICE and PM simulations having one particle per cell or more is excellent and halos have a power-law density profile, ρ(r) ∝ r−α, α ∈ [1.5, 1.8]. This slope, measured prior to any merger, is slightly larger than in the literature. The phase-space diagrams evidence complex but coherent patterns with clear signatures of self-similarity in the sine wave simulations, while the CDM halos are somewhat scribbly. After additional mass resolution tests, the PM simulations are used to follow the next stages of evolution. The power law progressively breaks down with a convergence of the density profile to the well-known Navarro–Frenk–White universal attractor, irrespective of initial conditions, that is even in the three-sine-wave simulations. This demonstrates again that mergers do not represent a necessary condition for convergence to the dynamical attractor. Not surprisingly, the measured pseudo phase-space density is a power law Q(r) ∝ r−αQ, with αQ close to the prediction of secondary spherical infall model, αQ ≃ 1.875. However this property is also verified during the early relaxation phase, which is non-trivial.
Simple mathematical model to predict the amount of energy produced in wind turbine - preliminary study
Authors: Borowski Sylwester , Soltysiak Agnieszka , Migawa Klaudiusz , Neubauer Andrzej
Published: January 2021

The manuscript presents a simple mathematical model for predicting the amount of energy produced in a wind turbine. As part of the own research, the data obtained from the SCADA program for the Enercon E-82 wind turbine was analyzed. It has been shown that it is possible to build a mathematical model to determine the amount of energy produced from the average wind speed. This method will be primarily useful for forecasting the volume of production as well as electricity demand, with particular emphasis on renewable energy sources. The application of the developed method in practice will facilitate and accelerate the implementation of the decision-making process in electricity production systems, while reducing the risk of error. This model can also be used to make repowering decisions.
How to quantify and avoid finite size effects in computational studies of crystal nucleation: The case of heterogeneous ice nucleation
Authors: Hussain Sarwar , Haji-Akbari Amir
Published: January 2021

Computational studies of crystal nucleation can be impacted by finite size effects, primarily due to unphysical interactions between crystalline nuclei and their periodic images. It is, however, not always feasible to systematically investigate the sensitivity of nucleation kinetics and mechanism to system size due to large computational costs of nucleation studies. Here, we use jumpy forward flux sampling to accurately compute the rates of heterogeneous ice nucleation in the vicinity of square-shaped model structureless ice nucleating particles (INPs) of different sizes and identify three distinct regimes for the dependence of rate on the INP dimension, L. For small INPs, the rate is a strong function of L due to the artificial spanning of critical nuclei across the periodic boundary. Intermediate-sized INPs, however, give rise to the emergence of non-spanning “proximal” nuclei that are close enough to their periodic images to fully structure the intermediary liquid. While such proximity can facilitate nucleation, its effect is offset by the higher density of the intermediary liquid, leading to artificially small nucleation rates overall. The critical nuclei formed at large INPs are neither spanning nor proximal. Yet, the rate is a weak function of L, with its logarithm scaling linearly with 1/L. The key heuristic emerging from these observations is that finite size effects will be minimal if critical nuclei are neither spanning nor proximal and if the intermediary liquid has a region that is structurally indistinguishable from the supercooled liquid under the same conditions.
Breakup of compound jets with inner droplets in a capillary flow-focusing device
Authors: Wang Ju , Liu Zhaomiao , Pang Yan , Li Mengqi , Zhou Qiang
Published: January 2021

The coupling between the multilayer interfaces in compound jets has notable effects on the structure and generation sequence of the formed double emulsions. These effects are important for the performance of double emulsions, such as the capacity, release rate, and controlled release threshold in medical and chemical applications. In this work, the influence of the inner droplet on the necking of compound jets is investigated in a horizontally placed capillary flow-focusing device based on microfluidics. Three types of interface coupling modes are explored. Scaling laws that describe the time evolution of the neck radius for these different coupling modes are analyzed, and the reasons for transitions between such scaling laws are discussed. The results show that the motion and deformation of the droplet have a large impact on the neck breakup in the inertial regime, causing the scaling law to change, but only a slight effect in the viscous regime. Moreover, the inner droplet can prevent the jet from breaking up owing to interface coupling. These findings could help us to understand the role of interface coupling in compound jets and provide a reference for controlling the generation of compound droplets.
Case studies of the time-dependent potential energy surface for dynamics in cavities
Authors: Martinez Phillip , Rosenzweig Bart , Hoffmann Norah M. , Lacombe Lionel , Maitra Neepa T.
Published: January 2021

The exact time-dependent potential energy surface driving the nuclear dynamics was recently shown to be a useful tool to understand and interpret the coupling of nuclei, electrons, and photons in cavity settings. Here, we provide a detailed analysis of its structure for exactly solvable systems that model two phenomena: cavity-induced suppression of proton-coupled electron-transfer and its dependence on the initial state, and cavity-induced electronic excitation. We demonstrate the inadequacy of simply using a weighted average of polaritonic surfaces to determine the dynamics. Such a weighted average misses a crucial term that redistributes energy between the nuclear and the polaritonic systems, and this term can in fact become a predominant term in determining the nuclear dynamics when several polaritonic surfaces are involved. Evolving an ensemble of classical trajectories on the exact potential energy surface reproduces the nuclear wavepacket quite accurately, while evolving on the weighted polaritonic surface fails after a short period of time. The implications and prospects for application of mixed quantum-classical methods based on this surface are discussed.
Linear to turbulent Görtler instability transition
Authors: Dagaut J. , Negretti M. E. , Balarac G. , Brun C.
Published: January 2021

We present results from a highly resolved large-eddy simulation of a freely developing Blasius profile over a concave boundary in a large spanwise domain. Due to the large initial Reynolds and Görtler numbers (Reθ,0 = 1175, Gθ,0 = 75), we observe the onset of two dominant wavelengths: the first dominating in the linear/transition region, λ1, and the second dominating in the turbulent region, λ2. Extending previous linear stability analysis (LSA) to higher Görtler numbers and non-dimensional wavenumbers, both dominant wavelengths of the Görtler instability correspond to predictions of LSA, the latter comparable to laminar theory by replacing the kinematic viscosity with the turbulent viscosity in the definition of the Görtler number. The predicted spatial modes compare well with the computed profiles for both λ1 and λ2. The skin friction coefficient Cf is found heterogeneous in the spanwise direction according to the emerging wavelengths λ1 and λ2 of the Görtler instability. We report a smooth increase in Cf from the theoretical predictions of a laminar boundary layer to those for a turbulent boundary layer over a flat plate. The values only slightly overshoot these predictions in the domain of existence of the second dominant wavelength λ2, very different from that reported at lower Reynolds numbers.
Where are the platypuses (Ornithorhynchus anatinus) now? A snapshot in time of their distribution in the Greater Brisbane region
Authors: Brunt Tamielle , Cecil Matt , Griffiths Josh , Adams-Hosking Christine , Murray Peter
Published: January 2021

Distribution data on platypus populations within the Greater Brisbane region is currently lacking, limiting our understanding of their population status. We report 4 years of platypus environmental DNA data from waterways in this region and compare them to historical observational records from 1990 to 2016 to determine any changes to their distribution. Twenty-one of the 54 eDNA sampled waterways were sampled multiple times and had records of previous platypus presence. Five of these 21 repeatedly sampled waterways (24%) did not have evidence of platypus presence, based on eDNA. This raises the concern that platypuses may no longer inhabit these waterways. We hope this study encourages further investigations on platypus to identify the extent of their decline within the region, along with possible broader state-wide review of their conservation status for future protection.
Development of revision and drafting in narrative and expository texts written by French children and adolescents (El desarrollo de la revisión y redacción de los textos narrativos y expositivos escritos por niños y adolescentes franceses)
Authors: Ailhaud Emilie , Chenu Florence , Jisa Harriet
Published: January 2021

Revisions in writing aim at text improvement. Literature has shown that revision activity differs between novice and experienced writers. Our ultimate goal is to understand how children and adolescents develop the capacity to shift perspectives from language producer to language recipient — a prerequisite ability to successful revision. In this study we analyse draft and final versions of expository and narrative texts produced by French children (36 participants for each group: fifth, seventh and ninth grades). Half of the children produced the written texts after having produced the text first in the spoken modality, and the other half produced the written versions before producing the text in the spoken modality. We will examine the kinds of revisions made by children and adolescents and how they vary with development and across text types. We also want to evaluate the measure to which our writers’ revisions contribute to text quality and to show how revisions can reveal what elements our participants judge as playing a part in text quality.
Forward coherent ω and ϕ mesons production in the photonuclear reaction on nuclei
Authors: Das Swapan
Published: January 2021

The differential cross sections of the forward coherent ω and ϕ mesons photoproduction from nuclei have been calculated using the Glauber model for the nuclear reaction. The measured cross section of the elementary reaction, i.e., γ
N → ω(ϕ)N reaction, are used as input in the Glauber model. The experimentally determined free-space scattering parameters of these mesons have been used to evaluate the meson nucleus interactions. The sensitivity of the cross section to the Fermi-motion and short-range correlation of the nucleon in the nucleus are studied. The calculated results are compared with the measured cross sections.
Arrhenius activation energy theory in radiative flow of Maxwell nanofluid
Authors: Rafiq K , Irfan M , Khan M , Anwar M S , A Khan W
Published: January 2021

Recently, nanofluids are habitually proficient to provide a process to intensify the probable heat transport of a structure with quite rare harmful influences formed by its addition. The usage of nanofluids and their optimum attentions has develop a range of prodigious concern with diverse nanofluid applications existence key to a structures attainment or interruption. Here the phenomena of activation energy and radiation in chemically reactive stagnation point Maxwell nanofluid have been elaborated. The magnetic properties with the influence of chemical reaction is also explored. The thermophoretic and Brownian dispersal are incorporated by utilizing the theory of Buongiorno model. The suitable conversions yield PDEs into ODEs. The facets of momentous parameters are examined via homotopic algorithm. The Brownian motion factor reports conflicting impact on temperature and concentration fields, respectively. The concentration field enhances for activation energy factor and decays for fitted rate constant. The Nusselt number decays for higher thermophoretic and Brownian factors.
Dynamic characteristic of a new fractional-order chaotic system based on the Hopfield Neural Network and its digital circuit implementation
Authors: Yang Feifei , Wang Xingyuan
Published: January 2021

In this paper, based on the principle of activation function between the neurons, we designed a Hopfield neural network (HNN) chaotic system. And then we defined a fractional-order HNN chaotic system by Caputo definition. The solution of the fractional-order HNN chaotic system is calculated by Adomain decomposition method (ADM). Then the dynamic performances of the fractional-order HNN chaotic system are analyzed through attractor phase diagram, bifurcation diagram, Lyapunov exponent spectrum, fractal dimension, chaotic diagram and SE complexity. In addition, the system is digital circuit implemented based on DSP platform. The experimental results show that the fractional-order HNN chaotic system not only has rich dynamic behavior, but also has complex nonlinear phenomena such as attractor coexistence which is sensitive to initial value. Therefore, this system has good potential application value, it can be used as multi-source pseudo-random number generator, and the generated pseudo-random sequence can be used in chaotic cryptography and secure communication.
The intrinsic SFRF and sSFRF of galaxies: comparing SDSS observation with IllustrisTNG simulation
Authors: Zhao Ping , Xu Haojie , Katsianis Antonios , Yang Xiao-Hu
Published: January 2021

The star formation rate function (SFRF) and specific star formation rate function (sSFRF) from observations are impacted by the Eddington bias, due to uncertainties in the estimated star formation rate (SFR). We develop a novel method to correct the Eddington bias and obtain the intrinsic SFRF and sSFRF from the Sloan Digital Sky Survey (SDSS) Data Release 7. The intrinsic SFRF is in good agreement with measurements from previous data in the literature that relied on UV SFRs but its high star-forming end is slightly lower than the corresponding IR and radio tracers. We demonstrate that the intrinsic sSFRF from SDSS has a bimodal form with one peak found at sSFR ∼ 10−9.7yr−1representing the star-forming objects while the other peak is found at sSFR ∼ 10−12yr−1representing the quenched population. Furthermore, we compare our observations with the predictions from the IllustrisTNG and Illustris simulations and affirm that the “TNG” model performs much better than its predecessor. However, we show that the simulated SFRF and CSFRD of TNG simulations are highly dependent on resolution, reflecting the limitations of the model and today’s state-of-the-art simulations. We demonstrate that the bimodal, two peaked sSFRF implied by the SDSS observations does not appear in TNG regardless of the adopted box-size or resolution. This tension reflects the need for inclusion of an additional efficient quenching mechanism in the TNG model.
The relaxation of galaxy clusters at redshift z = 0 in IllustrisTNG simulation
Authors: Li Chao , Zhu Ling , Guo Rui
Published: January 2021

We study the dynamical states of the 30 most massive galaxy clusters in the TNG100 simulation at redshift z = 0 using three types of tracers: stars, dark matter particles and satellite galaxies. If the massive galaxy cluster is spherically symmetric and relaxed, we can obtain the underlying total mass distribution accurately from its dynamical tracers using the spherical Jeans equations. Although the three tracers of clusters have very different number densities, velocity dispersions and anisotropies, they still trace the same total mass profile. We obtain the total mass profiles of clusters using these tracers separately and compare them with the true mass distributions. We find that: (1) the kinematics of dark matter trace the total mass of all clusters well and the mass inferred from dark matter are generally consistent with the true mass profiles with relative deviations smaller than ∼ 25% at all radii; (2) stars in ∼ 60% massive clusters are approaching equilibrium and the total mass of these clusters inferred from stars have relative deviations smaller than ∼ 50% at all radii. Stellar substructures are rich and the mass inferred from stars tend to be over-estimated in the inner region; and (3) satellite galaxies are unrelaxed in the inner region and become more relaxed as the radius increases. The total mass inferred from satellites are under-estimated in all regions.
A photometric-spectroscopic study of the infrared-excess eclipsing binary V2364 Cyg
Authors: Yuan Hui-Yu , Jiang Lin-Qiao , Dai Hai-Feng , Wang Shuang , Yang Yuan-Gui
Published: January 2021

The eclipsing binary V2364 Cyg is an A7V-type contact binary with a period of 0.5921 d. We present six spectra from LAMOST and BVRc
light curves (LCs), which are simultaneously analyzed to obtain the absolute physical parameters. The first light maxima are brighter than the second ones by up to

0
.
m

038

,

0
.
m

036

and

0
.
m

024

for BVRc
bands, respectively. These distorted LCs are modeled by a cool spot on the less massive component. Its mass ratio and over-contact degree are q = 0.319(±0.004) and f = 28.4%(±1.0)% respectively. From the mass-luminosity diagram, the primary component is a normal main-sequence star, while the secondary one is a subgiant star. From the (O – C) curve, the orbital period secularly decreases at a rate dP/dt = –1.62(±0.03)×10−7d yr−1, which is mainly attributed to mass loss via stellar wind from the binary system. This may result in the observed infrared excess in the W4 band.
Generating a radioheliograph image from SDO/AIA data with the machine learning method
Authors: Zhang Pei-Jin , Wang Chuan-Bing , Pu Guan-Shan
Published: January 2021

Radioheliograph images are essential for the study of solar short term activities and long term variations, while the continuity and granularity of radioheliograph data are not so ideal, due to the short visible time of the Sun and the complex electron-magnetic environment near the ground-based radio telescope. In this work, we develop a multi-channel input single-channel output neural network, which can generate radioheliograph image in microwave band from the Extreme Ultra-violet (EUV) observation of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). The neural network is trained with nearly 8 years of data of Nobeyama Radioheliograph (NoRH) at 17 GHz and SDO/AIA from January 2011 to September 2018. The generated radioheliograph image is in good consistency with the well-calibrated NoRH observation. SDO/AIA provides solar atmosphere images in multiple EUV wavelengths every 12 seconds from space, so the present model can fill the vacancy of limited observation time of microwave radioheliograph, and support further study of the relationship between the microwave and EUV emission.
Combined limit on the photon mass with nine localized fast radio bursts
Authors: Wei Jun-Jie , Wu Xue-Feng
Published: January 2021

A nonzero-mass hypothesis for the photon can produce a frequency-dependent dispersion of light, which results in arrival-time differences of photons with different frequencies originating from a given transient source. Extragalactic fast radio bursts (FRBs), with their low frequency emissions, short time durations, and long propagation distances, are excellent astrophysical probes to constrain the rest mass of the photon mγ
. However, the derivation of a limit on mγ
is complicated by the similar frequency dependences of dispersion expected from the plasma and nonzero photon mass effects. If a handful measurements of redshift for FRBs are available, then the different redshift dependences of the plasma and photon mass contributions to the dispersion measure (DM) might be able to break dispersion degeneracy in testing the photon mass. For now, nine FRBs with redshift measurements have been reported, which can turn this idea into reality. Taking into account the DM contributions from both the plasma and a possible photon mass, we use the data on the nine FRBs to derive a combined limit of mγ
≤ 7.1 × 10−51 kg, or equivalently mγ
≤ 4.0 × 10−15 eV/c
2 at 68 % confidence level, which is essentially as good as or represents a factor of 7 improvement over previous limits obtained by the single FRBs. Additionally, a reasonable estimation for the DM contribution from the host galaxy, DMhost, can be simultaneously achieved in our analysis. The rapid progress in localizing FRBs will further tighten the constraints on both mγ
and DMhost.
Spectral analysis of χ class data of GRS 1915+105 using TCAF solution
Authors: Banerjee Anuvab , Bhattacharjee Ayan , Debnath Dipak , Chakrabarti Sandip K.
Published: January 2021

The class variable source GRS 1915+105 exhibits a wide range of time variabilities on timescales of a few seconds to a few days. Depending on the count rates in different energy bands and the nature of the conventional color-color diagram, the variabilities were classified into sixteen classes that were later sequenced in ascending order of Comptonization Efficiency (CE), which is the ratio of power-law and blackbody photons. However, CE estimation is based on an empirical model which does not provide us with a comprehensive picture regarding accretion flow dynamics around the central source. In reality, the accretion flow is comprised of two components: the high angular momentumKeplerian flow in the form of a radiatively efficient disk and a low angular momentumradiatively inefficient sub-Keplerian halo enveloping the disk. These two components contribute differently to the overall flux due to the differences in their radiative efficiencies. Therefore, it is necessary to analyze the spectral behaviors and time variabilities in terms of accretion rates. In χ class, X-ray flux is steady with no significant variation, however various χ subclasses are observed at different X-ray fluxes and variations of count rates across different χ subclasses must be linked to the variation of flow parameters such as the accretion rates, be it the Keplerian disk rate and/or the low angular momentum halo rate. This motivated us to analyze the spectra of the χ class data implementing the physical Two Component Advective Flow (TCAF) solution which directly extracts these two rates from spectral fits. We find that in the χ
2,4 classes, which are reportedly devoid of significant outflows, the spectra could be fitted well applying the TCAF solution alone. In the χ
1,3 classes, which are always linked with outflows, a cutoff power-law model is needed in addition to the TCAF solution. At the same time, the normalization required by this model along with the variation of photon index and exponential roll-off factor provides us with information on the relative dominance of the outflow in the latter two classes. TCAF fit also supplies us with the size and location of the Compton cloud along with its optical depth. Thus by fitting with TCAF, a physical understanding of the flow geometry in different χ classes of GRS 1915+105 has been obtained.
On the possible orbital motion of Sgr A* in the smooth potential of the Milky Way
Authors: Nikiforov Igor’ I. , Veselova Angelina V.
Published: January 2021

The modern accuracy of measurements allows the residual/peculiar (Galactocentric) velocity of the supermassive black hole (SMBH) in our Galaxy, Sgr A*, on the order of several kilometers per second. We integrate possible orbits of the SMBH along with the surrounding nuclear stellar cluster (NSC) for a barred model of the Galaxy using modern constraints on the components of the SMBH Galactocentric velocity. Is is shown that the range of oscillations of the SMBH+NSC in a regular Galactic field in the plane of the Galaxy allowed by these constraints strongly depends on the set of central components of the Galactic potential. If the central components are represented only by a bulge/bar, for a point estimate of the SMBH Galactocentric velocity, the oscillation amplitude does not exceed 7 pc in the case that a classical bulge is present and reaches 25 pc if there is no bulge; with SMBH velocity components within the 2σ significance level, the amplitude can reach 15 and 50 pc, respectively. However, when taking into account the nuclear stellar disk (NSD), even in the absence of a bulge, the oscillation amplitude is only 5 pc for the point estimate of the SMBH velocity, and 10 pc for the 2σ significance level. Thus, the possible oscillations of the SMBH + NSC complex from the confirmed components of the Galaxy’s potential are mostly limited by the NSD, and even taking into account the uncertainty of the mass of the latter, the oscillation amplitude can hardly exceed 13 pc = 6′.
Development of machine learning techniques to enhance turbulence models
Authors: Razizadeh O , Yakovenko S N
Published: January 2021

The implementation of the machine learning methods of convolutional neural networks to enhance RANS closure models is presented. The RANS models are not universal and accurate, however they are computationally affordable. Finding a way to improve the model predictability will be an advantage. For this, machine learning algorithms based on available high-fidelity data sets for canonical flow cases obtained from DNS and measurements can be helpful. The application of these algorithms for a fully-developed turbulent channel flows with periodic hills, in a square duct and for other cases is considered.
Identification of connected arguments based on reasoning schemes “from expert opinion”
Authors: Salomatina N V , Kononenko I S , Sidorova E A , Pimenov I S
Published: January 2021

The work presented describes a combined approach to the partial extraction of the argumentative structure of a text that can be employed in the absence of sufficient annotated data to apply efficiently the machine learning methods for the direct detection of arguments and their relations. In this case, argument identification is performed by using the patterns of argumentation indicators created by a linguist and automatically expanded. These patterns enable the recognition of specific argument types with fine precision. In this study, arguments “from expert opinion” serve as such a pivot type. Besides, potential relations between recognized arguments are analyzed by dividing the text into superphrasal units (fragments united by one topic). The criterion for connecting arguments in an argumentative structure is their inclusion in the same superphrasal unit. An experiment for identifying potentially related arguments is conducted on a set of popular science texts with a minimum size of 1000 words.
The influence of the magnetic field on the quasistationary electric field penetration from the ground to the ionosphere
Authors: Nesterov S A , Denisenko V V
Published: January 2021

A quantitative model of the penetration of a quasistationary electric field from the Earth’s surface into the ionosphere with an inclined magnetic field has been developed. The results of the three-dimensional model are simpler regarding interpretation and explanation than those dimensional ones. The electric conductivity problem is solved using Fourier transform at each height. The space distributions of the electric field strength and the current density are calculated. The current lines are plotted. The electric field strength in the ionosphere is in the microvolt per meter range when it is about 100 V/m in the air near ground. The known approximate estimates of decrease in the electric field penetrating into the ionosphere with decrease in the magnetic latitude are confirmed and detailed. The penetration of the electric field and currents from the ground to the ionosphere through the atmospheric conductor cannot be a physical process which creates the observed ionospheric precursors of the earthquakes.
Solving of an Inverse Boundary Value Problem for the Heat Conduction Equation by Using Lavrentiev Regularization Method
Authors: Al-Mahdawi H K
Published: January 2021

In this paper, the inverse problem for the boundary value of the heat equation is posed and solved. It is well known that this problem classified as an ill-posed problem. The boundary value problem can be represented as an integral equation of the first kind by using the separation of variables method. The discretization of the integral equation allowed us to reduce the integral equation to a system of linear algebraic equations or a linear operator equation of the first kind on Hilbert spaces. In order to find an approximation solution, we need to apply a regularization algorithm. In this type of equation and through the regularization step we faced a non-injective operator problem. The Lavrentev regularization method was used to obtain the solution instead of the Tikhonov regularization method.
Comparative analysis of methods of recovering the well flow-rate and water-cut by thermodynamic measurements
Authors: Kabanikhin Sergey , Prikhodko Aleksei , Shishlenin Maxim
Published: January 2021

An important problem of oil well diagnostics is to quickly determine changes in the amount of liquid entering the well (flow rate), and the ratio of the amount of water to the amount of liquid (water cut). To calculate these parameters, thermodynamic measurements (temperature, pressure) can be used at the wellhead and downhole of the well, as well as garlands at the wellhead of sensors 10-20 meters long, with a frequency of 1 meter, for more information. The article presents a comparative analysis of algorithms for determining these parameters based on the solution of the inverse problem. The results of numerical calculations are presented.
Applicability of the single-scattering approximation for the ocean acoustic sounding
Authors: Vornovskikh P A , Prokhorov I V
Published: January 2021

A mathematical model in the work that describes the process of pulsed high-frequency acoustic sounding in a fluctuating ocean is considered. The inverse problem for the non-stationary equation of acoustic radiative transfer is investigated. It consists in finding the coefficient of volume scattering from the angular distribution of the radiation flux density at a given point in space. In the single scattering approximation, a formula is obtained to find the scattering coefficient. A series of computational experiments was carried out to substantiate its use in acoustic sensing of a fluctuating water medium. A numerical analysis has shown that the application of the single scattering approximation is justified at least at a sensing range of the order of 100 meters. Moreover, double and triple scattered fields have the main effect on the error.