bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flaring and Spot Activities on the Semi-detached Binary System KIC 06852488
Authors: Shi Xiang-dong , Qian Sheng-bang , Li Lin-jia , Liu Nian-ping 
Published: December 2020

Abstract
The continuous and unbroken time-series photometry data of Kepler and the Transiting Exoplanet Survey Satellite (TESS) provide a good opportunity to study the continuous variations in the light curve of binary stars. This paper reports the discoveries of the correlation between the two maxima on the light curve of KIC 06852488 and the correlation between the O’Connell effect and the O − C curve. The Max I and Max II vary with a same cycle length of ∼2000 days and a 180° phase difference, and the variation of the Max II coincides with the O − C curve of the primary light minima. After analyzing the Kepler and TESS light curves, it is detected that this binary is a semi-detached system with a mass ratio of 0.4622(±0.0036). The secondary component is filling its critical Roche lobe, while the primary component is only filling 12.25(±0.10)% of the lobe volume that contributes more than 85% luminosity of the total system. The variation of the O’Connell effect could be explained by an evolving hot spot on the primary component and an evolving cool spot on the secondary component. It is found that their positions are symmetrical with the inner Lagrange L1 point. After subtracting the binary brightness changes, six optical flares are detected that come from the cool secondary. We calculated the energy of flares and found that all of the flares are superflares. Both the flares and an evolving dark spot on the lobe-filling secondary component make the system a very interesting source to investigate the effects of binary interaction on the magnetic activities.
Probing the Milky Way’s Dark Matter Halo for the 3.5 keV Line
Authors: Sicilian Dominic , Cappelluti Nico , Bulbul Esra , Civano Francesca , Moscetti Massimo , Reynolds Christopher S. 
Published: December 2020

Abstract
We present a comprehensive search for the 3.5 keV line using ∼51 Ms of archival Chandra observations peering through the Milky Way’s dark matter halo from across the entirety of the sky, gathered via the Chandra Source Catalog Release 2.0. We consider the data’s radial distribution, organizing observations into four data subsets based on angular distance from the Galactic center. All data are modeled using both background-subtracted and background-modeled approaches to account for the particle instrument background, demonstrating the statistical limitations of the currently available ∼1 Ms of particle background data. A nondetection is reported in the total data set, allowing us to set an upper limit on 3.5 keV line flux and constrain the sterile neutrino dark matter mixing angle. The upper limit on sin2(2θ) is

(though systematic uncertainty may increase this by a factor of ∼2), corresponding to an upper limit on 3.5 keV line flux of

photons s−1 cm−2. These limits show consistency with recent constraints and several prior detections. Nondetections are reported in all radial data subsets, allowing us to constrain the spatial profile of 3.5 keV line intensity, which does not conclusively differ from Navarro–Frenk–White predictions. Thus, while offering heavy constraints, we do not entirely rule out the sterile neutrino dark matter scenario or the more general decaying dark matter hypothesis for the 3.5 keV line. We have also used the nondetection of any unidentified emission lines across our continuum to further constrain the sterile neutrino parameter space.
The Formation of an Atypical Sunspot Light Bridge as a Result of Large-scale Flux Emergence
Authors: Louis Rohan E. , Beck Christian , Choudhary Debi P. 
Published: December 2020

Abstract
We use a combination of full-disk data from the Solar Dynamics Observatory and high-resolution data from the Dunn Solar Telescope (DST) to study the formation, structure, and evolution of an atypical light bridge (LB) in a regular sunspot. The LB results from the emergence of magnetic flux with one footpoint rooted in a pore outside the parent sunspot that appears about 17 hr before the LB. The pore has a polarity opposite to that of the sunspot and recedes from it at a speed of about 0.4 km s−1. This is accompanied by the development of an elongated magnetic channel in the outer penumbra that triggers the formation of the LB when it reaches the inner penumbral boundary. The LB is a nearly horizontal structure with a field strength of about 1.2 kG that exhibits long-lived photospheric blueshifts of about 0.85 km s−1 along its entire length. The emergence of the LB leads to dynamic surges in the chromosphere and transition region about 13 minutes later. We derive the photospheric and chromospheric structure of the LB in the DST data from spectral line parameters and inversions of He i at 1083 nm, Si i at 1082.7 nm, Ca ii IR at 854 nm, and H
α
at 656 nm and speckle-reconstructed imaging at 700 and 430 nm. The LB shows an elongated filamentary shape in the photosphere without lateral extrusions. The thermal inversion of Ca ii IR reveals the LB to be about 600–800 K hotter than the umbra. Different sections of the LB are elevated to heights between 400 and 700 km. Our results indicate that LB formation is part of a flux emergence event with the LB envelope reaching a height of about 29 Mm before dissolving after about 13 hr. We conclude that the existence of persistent, large-scale photospheric blueshifts in LBs is the most likely criterion for distinguishing between flux emergence events and overturning convection in field-free umbral intrusions.
Frequency of Tidal Features Correlates with Age and Internal Structure of Early-type Galaxies
Authors: Yoon Yongmin , Lim Gu 
Published: December 2020

Abstract
Previous studies suggest that compact young early-type galaxies (ETGs) were formed by recent mergers. However, it has not yet been revealed whether tidal features that are direct evidence of recent mergers are detected frequently around compact young ETGs. Here, we investigate how the fraction of ETGs having tidal features (f

T
) depends on age and internal structure (compactness, color gradient, and dust lanes) of ETGs, using 650 ETGs with M

r
≤ −19.5 in 0.015 ≤ z ≤ 0.055 that are in deep coadded images of the Stripe 82 region of the Sloan Digital Sky Survey. We find that tidal features are more frequent in younger ETGs and more compact ETGs, so that compact young ETGs with ages ≲6 Gyr have high f

T
of ∼0.7 compared to their less compact or old counterparts with ages ≳ 9 Gyr that have f

T
≲ 0.1. Among compact young ETGs, those with blue cores have ∼3 times higher f

T
than those with red cores. In addition, ETGs with dust lanes have ∼4 times higher f

T
than those without dust lanes. Our results provide direct evidence that compact young ETGs especially with blue cores and ETGs with dust lanes are involved in recent mergers. Based on our results and several additional assumptions, we roughly estimate the typical visible time of tidal features after a merger, which is ∼3 Gyr in the depth of the Stripe 82 coadded images.
Toward Extremely Precise Radial Velocities. II. A Tool for Using Multivariate Gaussian Processes to Model Stellar Activity
Authors: Gilbertson Christian , Ford Eric B. , Jones David E. , Stenning David C. 
Published: December 2020

Abstract
The radial velocity method is one of the most successful techniques for the discovery and characterization of exoplanets. Modern spectrographs promise measurement precision of 0.2–0.5 m s−1 for an ideal target star. However, the intrinsic variability of stellar spectra can mimic and obscure true planet signals at these levels. Rajpaul et al. and Jones et al. proposed applying a physically motivated, multivariate Gaussian process (GP) to jointly model the apparent Doppler shift and multiple indicators of stellar activity as a function of time, so as to separate the planetary signal from various forms of stellar variability. These methods are promising, but performing the necessary calculations can be computationally intensive and algebraically tedious. In this work, we present a flexible and computationally efficient software package, GPLinearODEMaker.jl, for modeling multivariate time series using a linear combination of univariate GPs and their derivatives. The package allows users to easily and efficiently apply various multivariate GP models and different covariance kernel functions. We demonstrate GPLinearODEMaker.jl by applying the Jones et al. model to fit measurements of the apparent Doppler shift and activity indicators derived from simulated active solar spectra time series affected by many evolving starspots. We show how GPLinearODEMaker.jl makes it easy to explore the effect of different choices for the GP kernel. We find that local kernels could significantly increase the sensitivity and precision of Doppler planet searches relative to the widely used quasiperiodic kernel.
The Emergence of the X-Ray Luminosity/Cluster Richness Relation for Radio Galaxies
Authors: Garofalo David , Singh Chandra B. 
Published: December 2020

Abstract
The idea that mergers are more likely in dense groups or clusters coupled with the assumption that such events lead to cold gas flows onto black holes suggests a direct relationship between the radiative efficiency of an active galactic nucleus and environmental richness. Observations, however, increasingly challenge this and other basic expectations. Mounting evidence, for example, shows an inverse trend between near-Eddington accreting objects and environmental richness. Broken down by radio galaxy subgroup, recent work has explored connections between low excitation radio galaxies with Fanaroff–Riley II jet morphology (FR II LERGs) and other radio galaxies. We make contact with that work by adding a discussion of the recently discovered FR0 radio galaxies and show how to fit them in a picture in which FRII LERGs are not initial or final phases in the lifetime of a radio galaxy, but de facto transition states. We describe how to understand the observed X-ray luminosity/cluster richness relation as a fundamental correlation to the nature of the jet–disk connection.
Probing Interstellar Grain Growth through Polarimetry in the Taurus Cloud Complex
Authors: Vaillancourt John E. , Andersson B-G , Clemens Dan P. , Piirola Vilppu , Hoang Thiem , Becklin Eric E. , Caputo Miranda 
Published: December 2020

Abstract
The optical and near-infrared (OIR) polarization of starlight is typically understood to arise from the dichroic extinction of that light by dust grains whose axes are aligned with respect to a local magnetic field. The size distribution of the aligned-grain population can be constrained by measurements of the wavelength dependence of the polarization. The leading physical model for producing the alignment is that of radiative alignment torques (RATs), which predicts that the most efficiently aligned grains are those with sizes larger than the wavelengths of light composing the local radiation field. Therefore, for a given grain-size distribution, the wavelength at which the polarization reaches a maximum (

) should correlate with the characteristic reddening along the line of sight between the dust grains and the illumination source. A correlation between

and reddening has been previously established for extinctions up to

mag. We extend the study of this relationship to a larger sample of stars in the Taurus cloud complex, including extinctions

mag. We confirm the earlier results for

mag but find that the

versus A

V
relationship bifurcates above

mag, with part of the sample continuing the previously observed relationship. The remaining sample exhibits a steeper rise in

versus A

V
. We propose that the data exhibiting the steep rise represent lines of sight of high-density “clumps,” where grain coagulation has taken place. We present RAT-based modeling supporting these hypotheses. These results indicate that multiband OIR polarimetry is a powerful tool for tracing grain growth in molecular clouds, independent of uncertainties in the dust temperature and emissivity.
Problèmes géographiques des transitions énergétiques : quelles perspectives pour l’évolution du système énergétique ?
Authors: Deshaies Michel 
Published: December 2020

Les transitions énergétiques du XX e siècle ont créé un monde constitué de pays à des stades de développement différents, qui se traduisent par des consommations d’énergie primaire par habitant très inégales. La transition des énergies fossiles vers les énergies renouvelables va entraîner de profonds changements géographiques. Mais, pour que ces changements puissent se produire, encore faut-il que soient surmontées de nombreuses contraintes techniques et géographiques qui freinent le développement des énergies renouvelables. Cette transition énergétique ne peut être qu’un processus très long, au fur et à mesure que sera reconfiguré le système énergétique dans les différentes catégories de pays. Classification JEL : Q42, N50, O20
Vitamin D3–Induced Promotor Dissociation of PU.1 and YY1 Results in FcεRI Reduction on Dendritic Cells in Atopic Dermatitis
Authors: Herrmann Nadine , Nümm Tim J , Iwamoto Kazumasa , Leib Nicole , Koch Susanne , Majlesain Yasmin , Maintz Laura , Kirins Helene , Schnautz Sylvia , Bieber Thomas 
Published: December 2020

Abstract
Atopic dermatitis (AD) is a severe inflammatory skin disease. Langerhans cells and inflammatory dendritic epidermal cells (IDEC) are located in the epidermis of AD patients and contribute to the inflammatory processes. Both express robustly the high-affinity receptor for IgE, FcεRI, and thereby sense allergens. A beneficial role of vitamin D3 in AD is discussed to be important especially in patients with allergic sensitization. We hypothesized that vitamin D3 impacts FcεRI expression and addressed this in human ex vivo skin, in vitro Langerhans cells, and IDEC models generated from primary human precursor cells. We show in this article that biologically active vitamin D3 [1,25(OH)2-D3] significantly downregulated FcεRI at the protein and mRNA levels of the receptor’s α-chain, analyzed by flow cytometry and quantitative RT-PCR. We also describe the expression of a functional vitamin D receptor in IDEC. 1,25(OH)2-D3–mediated FcεRI reduction was direct and resulted in impaired activation of IDEC upon FcεRI engagement as monitored by CD83 expression. FcεRI regulation by 1,25(OH)2-D3 was independent of maturation and expression levels of microRNA-155 and PU.1 (as upstream regulatory axis of FcεRI) and transcription factors Elf-1 and YY1. However, 1,25(OH)2-D3 induced dissociation of PU.1 and YY1 from the FCER1A promotor, evaluated by chromatin immunoprecipitation. We show that vitamin D3 directly reduces FcεRI expression on dendritic cells by inhibiting transcription factor binding to its promotor and subsequently impairs IgE-mediated signaling. Thus, vitamin D3 as an individualized therapeutic supplement for those AD patients with allergic sensitization interferes with IgE-mediated inflammatory processes in AD patients.
GSK3 Restrains Germinal Center B Cells to Form Plasma Cells
Authors: Lee Jeonghyun , Park Hyosung , Lim Jiwon , Jin Hyung-Seung , Park Yoon , Jung Yu-Jin , Ko Hyun-Jeong , Yoon Sung-Il , Lee Geun-Shik , Kim Pyeung-Hyeun , Choi Sun Shim , Xiao Changchun , Kang Seung Goo 
Published: December 2020

Abstract
B cells in the germinal center (GC) are programmed to form plasma cells (PCs) or memory B cells according to signals received by receptors that are translated to carry out appropriate activities of transcription factors. However, the precise mechanism underlying this process to complete the GC reaction is unclear. In this study, we show that both genetic ablation and pharmacological inhibition of glycogen synthase kinase 3 (GSK3) in GC B cells of mice facilitate the cell fate decision toward PC formation, accompanied by acquisition of dark zone B cell properties. Mechanistically, under stimulation with CD40L and IL-21, GSK3 inactivation synergistically induced the transcription factors Foxo1 and c-Myc, leading to increased levels of key transcription factors required for PC differentiation, including IRF4. This GSK3-mediated alteration of transcriptional factors in turn facilitated the dark zone transition and consequent PC fate commitment. Our study thus reveals the upstream master regulator responsible for interpreting external cues in GC B cells to form PCs mediated by key transcription factors.
Assessment of Sars-Cov-2 Infection through Rapid Serology Testing in the Homeless Population in the City of Rome, Italy. Preliminary Results
Authors: Ralli Massimo , Cedola Chiara , Urbano Suleika , Latini Ottavio , Shkodina Natalia , Morrone Aldo , Arcangeli Andrea , Ercoli Lucia 
Published: December 2020

Background The development of COVID-19 pandemic has affected all segments of the population; however, it had a significant impact on vulnerable subjects, such as in people experiencing homelessness. The aim of this study was to evaluate the prevalence of COVID-19 spread in homeless persons in the city of Rome, Italy. Design and methods Patients included in the study underwent a clinical evaluation and rapid antibody analysis on capillary blood for the presence of immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies to SARS-CoV-2 virus. Symptomatic patients were not included in the screening and immediately referred to local hospitals for further evaluation. Results One-hundred seventy-three patients of both sexes were tested for SARS-CoV-2 infection through rapid serological test. Age range was 10-80 years; people came from 35 different countries of origin and 4 continents. Test results were negative for most patients (170-98.2%); two patients had positive IgM (1.2%) and one patient had positive IgG (0.6%). Conclusions Our study is the first to evaluate the prevalence of SARS-CoV-2 infection in people experiencing homelessness in the city of Rome, Italy. Most patients were negative for COVID- 19, although several factors may have had an impact on this result, such as the exclusion of symptomatic patients, the limited sensitivity of rapid serological tests in the initial stage of infection and the prevention measures adopted in these populations. Larger studies on fragile populations are needed to prevent and intercept new clusters of infection in the upcoming months.
GIẢI PHƯƠNG TRÌNH ĐẠO HÀM RIÊNG SỬ DỤNG MẠNG NEURAL NHÂN TẠO
Authors: DAC QUAN HO , TRUNG HIEU HUYNH 
Published: December 2020

Phương trình đạo hàm riêng đã được ứng dụng rộng rãi trong các lĩnh vực khác nhau của đời sống như vật lý, hóa học, kinh tế, xử lý ảnh vv. Trong bài báo này chúng tôi trình bày một phương pháp giải phương trình đạo hàm riêng (partial differential equation - PDE) thoả điều kiện biên Dirichlete sử dụng mạng neural truyền thẳng một lớp ẩn (single-hidden layer feedfordward neural networks - SLFN) gọi là phương pháp mạng neural (neural network method – NNM). Các tham số của mạng neural được xác định dựa trên thuật toán huấn luyện mạng lan truyền ngược (backpropagation - BP). Kết quả nghiệm PDE thu được bằng phương pháp NNM chính xác hơn so với nghiệm PDE giải bằng phương pháp sai phân hữu hạn.
The suspended small-particle layer in the oxygen-poor Black Sea: a proxy for delineating the effective N2-yielding section
Authors: Rasse Rafael , Claustre Hervé , Poteau Antoine 
Published: December 2020

Abstract. The shallower oxygen-poor water masses of the ocean confine a majority of the microbial communities that can produce up to 90 % of
oceanic N2. This effective N2-yielding section encloses a
suspended small-particle layer, inferred from particle backscattering
(bbp) measurements. It is thus hypothesized that this layer (hereafter,
the bbp-layer) is linked to microbial communities involved in
N2 yielding such as nitrate-reducing SAR11 as well as sulfur-oxidizing, anammox, and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end,
we evaluate how the key drivers of N2-yielding bacteria dynamics impact
the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results
suggest that the bbp-layer is at least partially composed of the bacteria
driving N2 yielding for three main reasons: (1) strong correlations are
recorded between bbp and nitrate; (2) the top location of the
bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while
its thickness is modulated by the amount of nitrate available to produce
N2; and (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where bacteria involved in N2 yielding coexist. We thus
advance that bbp and O2 can be exploited as a combined proxy to
delineate the N2-yielding section of the Black Sea. This proxy can
potentially contribute to refining delineation of the effective
N2-yielding section of oxygen-deficient zones via data from the growing
BGC-Argo float network.
Holocene vegetation dynamics in response to climate change and hydrological processes in the Bohai region
Authors: Jinxia Chen , Xuefa Shi , Yanguang Liu , Shuqing Qiao , Shixiong Yang , Shijuan Yan , Huahua Lv , Jianyong Li , Xiaoyan Li , Chaoxin Li 
Published: December 2020

Abstract. Coastal vegetation both mitigates the damage inflicted by marine disasters
on coastal areas and plays an important role in the global carbon cycle
(i.e., blue carbon). Nevertheless, detailed records of changes in coastal
vegetation composition and diversity in the Holocene, coupled with climate
change and river evolution, remain unclear. To explore vegetation dynamics
and their influencing factors on the coastal area of the Bohai Sea (BS)
during the Holocene, we present high-resolution pollen and sediment grain
size data obtained from a sediment core of the BS. The results reveal that
two rapid and abrupt changes in salt marsh vegetation are linked with the
river system changes. Within each event, a recurring pattern – starting with a decline in Cyperaceae, followed by an increase in Artemisia and Chenopodiaceae – suggests a successional process that is determined by the close relationship between Yellow River (YR) channel shifts and the wetland community dynamics. The phreatophyte Cyperaceae at the base of each sequence indicate lower saline conditions. Unchannelized river flow characterized the onset of the YR channel shift, caused a huge river-derived sediment accumulation in the floodplain and destroyed the sedges in the coastal depression. Along with the formation of a new channel, lateral migration of the lower channel stopped, and a new intertidal mudflat was formed. Pioneer species (Chenopodiaceae, Artemisia) were the first to colonize the bare zones of the
lower and middle marsh areas. In addition, the pollen results revealed that
the vegetation of the BS land area was dominated by broadleaved forests
during the Early Holocene (8500–6500 BP) and by conifer and broadleaved
forests in the Middle Holocene (6500–3500 BP), which was followed by an
expansion of broadleaved trees (after 3500 BP). The pollen record
indicated that a warmer Early and Late Holocene and colder Middle Holocene
were consistent with previously reported temperature records for East Asia.
The main driving factors of temperature variation in this region are
insolation, the El Niño–Southern Oscillation and greenhouse gases
forcing.