bluuebunny/crossref_metadata_2025_split huggingface dataset:
Online data analysis system of the INTEGRAL telescope
Authors: Neronov A. , Savchenko V. , Tramacere A. , Meharga M. , Ferrigno C. , Paltani S. 
Published: April 2021

Context. During more than 17 years of operation in space, the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) telescope has accumulated a large data set that contains records of hard X-ray and soft γ-ray astronomical sources. These data can be reused in the context of multi-wavelength or multi-messenger studies of astronomical sources and have to be preserved on long timescales.
Aims. We present a scientific validation of an interactive online INTEGRAL data analysis system for multi-wavelength studies of hard X-ray and soft γ-ray sources.
Methods. The online data analysis system generates publication-quality high-level data products: sky images, spectra, and light curves in response to user queries that define analysis parameters such as source position, time and energy interval, and binning. The data products can be requested via a web browser interface or via an application programming interface that is available as a Python package. The products for the Imager on Board the INTEGRAL Satellite/INTEGRAL Soft Gamma-Ray Imager instrument of INTEGRAL are generated using the offline science analysis (OSA) software, which is provided by the instrument teams and is conventionally used to analyse INTEGRAL data. The analysis workflow is organised to preserve and reuse various intermediate analysis products, ensuring that frequently requested results are available without delay. The platform is implemented in a Docker cluster that allows operation of the software in a controlled virtual environment and can be deployed in any compatible infrastructure. The scientific results produced by the open data analysis (ODA) are identical to those produced by OSA because ODA simply provides a platform to retrieve the OSA results online while leveraging a provenance-indexed database of precomputed (cached) results to optimise and reuse the result.
Results. We report the functionalities and performance of the online data analysis system by reproducing the benchmark INTEGRAL results on different types of sources, including bright steady and transient Galactic sources, and bright and weak variable extra-galactic sources. We compare the results obtained with the online data analysis system with previously published results on these sources. We also discuss limitations of the online analysis system.
Conclusions. We consider the INTEGRAL online data analysis as a demonstration of a more general web-based ‘data analysis as a service’ approach that provides a promising solution for the preservation and maintenance of data analysis tools of astronomical telescopes on (multi)decade long timescales and facilitates combining data in multi-wavelength and multi-messenger studies of astronomical sources.
The effects of the initial mass function on Galactic chemical enrichment
Authors: Goswami S. , Slemer A. , Marigo P. , Bressan A. , Silva L. , Spera M. , Boco L. , Grisoni V. , Pantoni L. , Lapi A. 
Published: April 2021

Context. We have been seeing mounting evidence that the stellar initial mass function (IMF) might extend far beyond the canonical Mi ∼ 100 M⊙ limit, but the impact of such a hypothesis on the chemical enrichment of galaxies is yet to be clarified.
Aims. We aim to address this question by analysing the observed abundances of thin- and thick-disc stars in the Milky Way with chemical evolution models that account for the contribution of very massive stars dying as pair instability supernovae.
Methods. We built new sets of chemical yields from massive and very massive stars up to Mi ∼ 350 M⊙ by combining the wind ejecta extracted from our hydrostatic stellar evolution models with explosion ejecta from the literature. Using a simple chemical evolution code, we analysed the effects of adopting different yield tables by comparing predictions against observations of stars in the solar vicinity.
Results. After several tests, we set our focus on the [O/Fe] ratio that best separates the chemical patterns of the two Milky Way components. We find that with a standard IMF, truncated at Mi ∼ 100 M⊙, we can reproduce various observational constraints for thin-disc stars; however, the same IMF fails to account for the [O/Fe] ratios of thick-disc stars. The best results are obtained by extending the IMF up to Mi = 350 M⊙, while including the chemical ejecta of very massive stars in the form of winds and pair instability supernova (PISN) explosions.
Conclusions. Our study indicates that PISN may have played a significant role in shaping the chemical evolution of the thick disc of the Milky Way. Including their chemical yields makes it easier to reproduce not only the level of the α-enhancement, but also the observed slope of thick-disc stars in the [O/Fe] vs. [Fe/H] diagram. The bottom line is that the contribution of very massive stars to the chemical enrichment of galaxies is potentially quite important and should not be neglected in models of chemical evolution.
Stability of solar atmospheric structures harboring standing slow waves
Authors: Geeraerts M. , Van Doorsselaere T. 
Published: April 2021

Context.In the context of the solar coronal heating problem, one possible explanation for the high coronal temperature is the release of energy by magnetohydrodynamic (MHD) waves. The energy transfer is believed to be possible, among others, by the development of the Kelvin-Helmholtz instability (KHI) in coronal loops.Aims.Our aim is to determine if standing slow waves in solar atmospheric structures such as coronal loops, and also prominence threads, sunspots, and pores, can trigger the KHI due to the oscillating shear flow at the structure’s boundary.Methods.We used linearized nonstationary MHD to work out an analytical model in a cartesian reference frame. The model describes a compressible plasma near a discontinuous interface separating two regions of homogeneous plasma, each harboring an oscillating velocity field with a constant amplitude which is parallel to the background magnetic field and aligned with the interface. The obtained analytical results were then used to determine the stability of said interface, both in coronal and photospheric conditions.Results.We find that the stability of the interface is determined by a Mathieu equation. In function of the parameters of this equation, the interface can either be stable or unstable. For coronal as well as photospheric conditions, we find that the interface is stable with respect to the KHI. Theoretically, it can, however, be unstable with respect to a parametric resonance instability, although it seems physically unlikely. We conclude that, in this simplified setup, a standing slow wave does not trigger the KHI without the involvement of additional physical processes.
Enantioselective Functionalization of Prochiral Cyclobutanones and Cyclobutenones
Authors: Lu Ping , Wang Meng , Zhong Changxu 
Published: April 2021

AbstractEnantioselective synthesis of cyclobutane derivatives is still a challenging topic in asymmetric synthesis. [2+2] Cycloaddition and skeleton rearrangement are two primary strategies to this end. Recently, functionalization of cyclobutanones and cyclobutenones, which are readily available via [2+2] cycloadditions as prochiral substrates, has emerged as a powerful tool to access versatile four-membered ring compounds. Herein, we summarize some recent advances in these areas from our and other groups.1	Introduction2	Enantioselective Functionalization of Cyclobutanones2.1	Chiral Lithium Amide Approach2.2	Enamine Approach3	Enantioselective Functionalization of Cyclobutenones4	Conclusion
Coordination compounds of biogenic metals as cytotoxic agents in cancer therapy
Authors: Guk Dmitry A. , Krasnovskaya Olga O. , Beloglazkina Elena K. 
Published: April 2021

AbstractThe review summarizes the data on the structures and methods for the synthesis of compounds with anticancer activity based on biogenic metals, which can replace platinum drugs prevailing in cytotoxic therapy. The main focus is given to the comparison of the mechanisms of the cytotoxic action of these complexes, their efficacy and prospects of their use in clinical practice. This is the first systematic review of cytotoxic zinc, iron, cobalt and copper compounds. The structure – activity relationships and the mechanisms of antitumour action are formulated for each type of metal complexes.The bibliography includes 181 references.
Erwinia amylovora (fireblight).
Authors: Vanneste Joel 
Published: April 2021

Abstract

The long distance spread of fire blight is a rare event which in most cases seems to be the result of plants or plant tissues being moved across the oceans. Short distance spread is the result of the characteristics of the pathogen, especially its ability to produce an exudate (bacteria embedded in exopolysaccharides) which is easily transported by wind, rain, insects or birds. This is very efficient; once the pathogen has moved into a new territory it almost always colonizes and becomes established. This is accompanied by economic losses in regions where apple, pear or loquat are grown commercially; it might prevent the survival of local cultivars and could disrupt international trade. To date fire blight has colonized most of North America, Western Europe and most of the countries around the Mediterranean Sea as well as New Zealand. Outbreaks of fire blight are irregular and difficult to control.
Sugarcane grassy shoot phytoplasma (grassy shoot of sugarcane).
Authors: Marcone Carmine 
Published: April 2021

Abstract

The incidence of sugarcane grassy shoot (SCGS) disease may reach up to 70% or more as is often true for ratoon crops resulting in yield losses of 40-90%, but often approaching 100% (Rishi and Chen, 1989; Viswanathan, 1997, 2001a; Rao and Dhumal, 2002; Srivastava et al., 2006).
Right-wing populism as a worldview and online practice: Social media communication by ordinary citizens between ideology and lifestyles
Authors: Krämer Benjamin , Fernholz Tobias , Husung Tobias , Meusel Julia , Voll Magdalena 
Published: April 2021

ABSTRACT
Right-wing populist ideologies are expressed not only by politicians, party members or mass media actors but also by non-organised citizens on social media. On these platforms, political messages alternate with posts revealing personal lifestyles. We assume that an increasingly coherent political milieu and identity are emerging around right-wing populist worldviews that manifest themselves in social media practices and correspond with expressions of other aspects of lifestyles. A qualitative study of social media accounts of users who expressed a right-wing populist worldview was conducted. We investigate how core elements of right-wing populism are being communicated by these users, reconstruct a typical vision of society that links political concerns with users’ everyday way of life, identify political and social topics beyond the core of right-wing populism, and analyse how these different elements of online expression are held together by a specific style of thinking and communication.
Reconstruction of a single-active-electron potential from electron momentum distribution produced by strong-field ionization using optimization technique
Authors: Shvetsov-Shilovski N I 
Published: April 2021

Abstract
We present a method for retrieving of single-active electron potential in an atom or molecule from a given momentum distribution of photoelectrons ionized by a strong laser field. In this method the potential varying within certain limits is found as the result of the optimization procedure aimed at reproducing the given momentum distribution. The optimization using numerical solution of the time-dependent Schrödinger equation for ionization of a model one-dimensional atom shows the good accuracy of the potential reconstruction method. This applies to different ways used for representing of the potential under reconstruction, including a parametrization and determination of the potential by specifying its values on a spatial grid.
Nanoscale control of temperature operation ranges for magnetocaloric applications
Authors: Salcedo Gallo Juan Sebastián , Berger Andreas , Quintana Mikel , Restrepo Parra Elisabeth , Fallarino Lorenzo 
Published: April 2021

Abstract
We devised a proof-of-concept materials design that addresses the necessary requirements for magnetocaloric materials to have a constant magnetocaloric effect (MCE) over a large temperature range. For this purpose, we have fabricated epitaxial Co1−x(z)Ru
x

(z) films engineered to have a triangular gradient in exchange strength J along the thickness. Different from homogeneous Co1−x
Ru
x
layers, where the maximum value of magnetic entropy change ΔS
m falls rapidly with temperature away from the ferromagnetic (FM)–paramagnetic (PM) phase transition, the Co1−x(z)Ru
x

(z) graded structures exhibit high MCE over a large temperature range, leading to an improved cooling capacity. Theoretical modeling results confirm the enhanced temperature range and highlight a core aspect of our exchange graded materials approach, namely the ability to control and manipulate magnetism at nanoscale dimensions. As we demonstrate, this control is reliant on the fact that the temperature driven PM–FM phase transition does not occur in the entirety of the material system but only in well-defined nanoscopic regions of our samples at any given temperature, enabling us to significantly extend the useful temperature range for magneto-caloric utilization.
Defect passivation in CH3NH3PbI3 films using alkali metal fluoride additives for highly efficient perovskite solar cells
Authors: Xu Pengyu , Piao Hongjing , Liu Shuai , Hu Haihua , Ding Jiajie , Bao Jiahui , Wang Peng , Wu Xiaoping , Xu Lingbo , Lin Ping , He Haiyan , Cui Can 
Published: April 2021

Abstract
Solution-processed organic/inorganic hybrid halide perovskites are a class of very promising photovoltaic materials because of their extraordinary optoelectronic properties. However, numerous intrinsic defects within perovskite films limit the performance enhancement of perovskite solar cells (PSCs). Herein, we introduce three different alkali metal fluoride additives into the perovskite precursor to modulate the defect behaviors. The addition of alkali metal fluorides, especially potassium fluoride (KF), significantly passivates grain boundaries and point defects within bulk perovskite films, contributing to increased carrier lifetime and reduced defect state density. By optimizing the concentration of additives, the PSC device with 1% KF added has realized a significantly enhanced power conversion efficiency of 20.11%, and ignorable hysteresis.
Radon protection in apartments using a ventilation system wireless-controlled by radon activity concentration
Authors: Dehnert Jörg , Altendorf Diana , Trabitzsch Ralf , Grünewald Hannes , Geisenhainer Ralph , Oeser Veikko , Streil Teresa , Weber Louis , Schönherr Bernd , Thomas Joachim , Forner Katrin , Alisch-Mark Mandy , Weiss Holger 
Published: April 2021

Abstract
The new German Radiation Protection Act (StrlSchG) of 31 December 2018 established a reference value of 300 Bq m−3 for the annual average radon activity concentration in buildings with recreation and living rooms, as well as in workplaces. It is expected that the reference value will be exceeded in a vast number of buildings throughout Germany and that radon protection measures will become indispensable. A simple and inexpensive radon protection measure for existing buildings is ventilation. In the scope of a joint project, ventilation systems with zone control and heat recovery are to be extended by the control parameter radon activity concentration. A highly sensitive, miniaturized radon monitor will be developed for this purpose, which can be integrated wirelessly into ventilation systems. Radon measurements were carried out in 13 apartments of an unoccupied heated apartment block in Germany over a period of three weeks in the wintertime. High radon activity concentrations were found on all three floors. The maximum values were 14000 Bq m−3 on the first floor, 6000 Bq m−3 on the second floor, and 2000 Bq m−3 on the third floor. Ventilation experiments were carried out in an apartment with high radon activity concentration. Two decentralized ventilation systems with heat recovery were installed in each of the two opposite outside walls. The controlling device of the system was activated wirelessly depending on the radon activity concentration. The radon activity concentration was reduced from 8000 Bq m−3 to 800 Bq m−3 in a first experiment in the living room.
Enhancement of ferroelectricity and homogeneity of orthorhombic phase in Hf0.5Zr0.5O2 thin films
Authors: Zou Zhengmiao , Tian Guo , Wang Dao , Zhang Yan , Wang Jiali , Li Yushan , Tao Ruiqiang , Fan Zhen , Chen Deyang , Zeng Min , Gao Xingsen , Dai Ji-Yan , Lu Xubing , Liu J-M 
Published: April 2021

Abstract
By adoption of a high permittivity ZrO2 capping layer (ZOCL), enhanced ferroelectric properties were achieved in the Hf0.5Zr0.5O2 (HZO) thin films. For HZO thin film with 10 Å ZOCL, the 2P

r
value can reach as high as ∼43.1 μC cm−2 under a sweep electric field of 3 MV cm−1. In addition, a reduced coercive field of 1.5 MV cm−1 was observed, which is comparable to that of HZO with metallic CL. Furthermore, the homogeneity of ferroelectric orthorhombic phase in HZO films was observed to be clearly increased, as evidenced by nanoscale piezoelectric force microscopy measurements. These results demonstrate that ZOCL is very favorable for high performance ferroelectric HZO films and their future device applications.
Learning non-local perfusion textures for high-quality computed tomography perfusion imaging
Authors: Li Sui , Zeng Dong , Bian Zhaoying , Li Danyang , Zhu Manman , Huang Jing , Ma Jianhua 
Published: April 2021

Abstract

Background. Computed tomography perfusion (CTP) imaging plays a critical role in the acute stroke syndrome assessment due to its widespread availability, speed of image acquisition, and relatively low cost. However, due to its repeated scanning protocol, CTP imaging involves a substantial radiation dose, which might increase potential cancer risks. Methods. In this work, we present a novel deep learning model called non-local perfusion texture learning network (NPTN) for high-quality CTP imaging at low-dose cases. Specifically, considering abundant similarities in the CTP images, i.e. latent self-similarities within the non-local region in the CTP images, we firstly search the most similar pixels from the adjacent frames within a fixed search window to obtain the non-local similarities and to construct non-local textures vector. Then, both the low-dose frame and these non-local textures from adjacent frames are fed into a convolution neural network to predict high-quality CTP images, which can help better characterize the structure details and contrast variants in the targeted CTP image rather than simply utilizing the targeted frame itself. The residual learning strategy and batch normalization are utilized to boost the performance of the convolution neural network. In the experiment, the CTP images of 31 patients with suspected stroke disease are collected to demonstrate the performance of the presented NPTN method. Results. The results show the presented NPTN method obtains superior performance compared with the competing methods. From numerical value, at all dose levels, the presented NPTN method has achieved around 3.0 dB improvement of average PSNR, an increase of around 1.4% of average SSIM, and a decrease of around 4.8% of average RMSE in the low-dose CTP reconstruction task, and also has achieved an increase of around 3.4% of average SSIM and a decrease of around 61.1% of average RMSE in the cerebral blood flow (CBF) estimation task. Conclusions. The presented NPTN method can obtain high-quality CTP images and estimate high-accuracy CBF map by characterizing more structure details and contrast variants in the CTP image and outperform the competing methods at low-dose cases.
Ultra-sensitive passive wireless sensor exploiting high-order exceptional point for weakly coupling detection
Authors: Zeng Chao , Zhu Kejia , Sun Yong , Li Guo , Guo Zhiwei , Jiang Jun , Li Yunhui , Jiang Haitao , Yang Yaping , Chen Hong 
Published: April 2021

Abstract
Since the quantum concept of parity-time (PT) symmetry has been introduced into the conventional inductor–capacitor resonance, strategies based on exceptional points (EP) based strategies redefine our understanding of sensitivity limitation. This considerable enhancement of sensitivity originated in exploration of the non-Hermitian physics in photonics, acoustics and electronics, which exhibits a substantial application to the miniaturization of implanted electronic sensors in medicine field. By continuously accessing the EP, the spectral response of reader ∆ω follows a dependency of Δω ∼ κ
2/3 to a weakly coupling rate (|κ| ≈ 0), which may approach the theoretical limit of sensitivity in a second-order EP system. In this paper, we experimentally demonstrate a high-order (higher than second-order) PT symmetric system for weak coupling detection, in which a third-order EP can be employed to fulfill the sensitivity of Δω ∼ κ
1/2. Particularly, we introduce the incoming wave as an effective gain to balance the loss and obtain a pair of purely real eigenfrequencies. There are absence of imaginary parts despite corresponding real parts shifts dramatically by using a neutral resonator, without a broadening of the reflection spectrum so that maintaining a high resolution on the sensitivity. This work may reveal the physical mechanics of a small perturbation at a high-order EP and promote applications in implanted medicine devices.
Impact of uniform and non-uniform heated rods on free convective flow inside a porous enclosure: finite element analysis
Authors: Yasin Amna , Ullah Naeem , Saleem S , Nadeem Sohail , Al-Zubaidi A 
Published: April 2021

Abstract
A numerical study of laminar natural convective flow in a porous rectangular cavity having two heated rods is performed in this article. Both heated rods are placed in the middle of the cavity. Further, it is assumed that the flow and isothermal contours are influenced by permeable medium. Physical laws transform this physical setup into the mathematical form, which is expressed as partial differential equation. Finite element method is adopted to get the solution of these partial differential equations, the results against various flow controlling variables are presented in contour plots and line graphs. Results illustrate that in the case of non-uniform heating, the heat transfer rate is suppressed with the enhancement Rayleigh parameter as compared to uniform heating. In addition, with the increase in heated length of rods, flow field gets stronger due to stronger buoyancy effects. Moreover, the velocity distribution and Nusselt number are enhanced with the rise of permeability of porous medium.
Thermodynamic and magnetocaloric properties of a triple-layer graphene-like structure
Authors: Sun Lei , Lv Dan , Wang Wei , Gao Zhong-yue , Li Bo-chen 
Published: April 2021

Abstract
Thermodynamic and magnetocaloric properties of the triple-layer graphene-like structure with mixed spin-3/2 and spin-5/2 have been reported by applying the Monte Carlo simulation. We found that for such system, various exchange couplings or external magnetic field affect greatly the magnetic behaviors and magnetocaloric effect. For example, the value of magnetization increases and the system becomes more stable with increasing the exchange couplings or external magnetic field. Besides, there exists a peak in each magnetic entropy change curve near the critical temperature. The value of it increases with decreasing exchange couplings or increasing the external magnetic field. In addition, when the exchange couplings decreases or the external magnetic field increases, the relative cooling power enhances. Finally, the hysteresis behaviors have also been investigated in detail.