bluuebunny/crossref_metadata_2025_split huggingface dataset:
Active Galactic Nuclei: Boon or Bane for Biota?
Authors: Lingam Manasvi , Ginsburg Idan , Bialy Shmuel 
Published: May 2019

Abstract
Active galactic nuclei (AGNs) emit substantial fluxes of high-energy electromagnetic radiation, and have therefore attracted some recent attention for their negative impact on galactic habitability. In this paper, we propose that AGNs may also engender the following beneficial effects: (i) prebiotic synthesis of biomolecular building blocks mediated by ultraviolet (UV) radiation, and (ii) powering photosynthesis on certain free-floating planets and moons. We also reassess the harmful biological impact of UV radiation originating from AGNs, and find that their significance could have been overestimated. Our calculations suggest that neither the positive nor negative ramifications stemming from a hypothetical AGN in the Milky Way are likely to affect putative biospheres in most of our Galaxy. On the other hand, we find that a sizable fraction of all planetary systems in galaxies with either disproportionately massive black holes (∼109–10
M
⊙) or high stellar densities (e.g., compact dwarf galaxies) might be susceptible to both the beneficial and detrimental consequences of AGNs, with the former potentially encompassing a greater spatial extent than the latter.
Parallel Electron Heating by Tangential Discontinuity in the Turbulent Magnetosheath
Authors: Liu Y. Y. , Fu H. S. , Liu C. M. , Wang Z. , Escoubet P. , Hwang K.-J. , Burch J. L. , Giles B. L. 
Published: May 2019

Abstract
Energetic electrons exist widely in the turbulent magnetosheath, but how they are generated remains unclear. Here we report a new structure, at which electrons are efficiently accelerated in the direction parallel to the magnetic field. Such a structure, formed at the edge of a high-speed jet (HSJ), is a tangential discontinuity (TD) in the MHD regime, but exhibits impulsive fine structures in the kinetic-scale regime. The pulsation of the TD, caused by time-varying size of the HSJ, leads to the energization process: when the transverse section of the HSJ increases, a magnetic mirror is formed and subsequently electrons are trapped and accelerated via the Fermi mechanism; when the transverse section of the HSJ decreases, the magnetic mirror disappears and subsequently electrons escape. Such parallel electron heating can lead to three times of parallel-temperature increase; it can shed light on the study of electron heating in the solar wind, where TDs exist extensively.
Deep Neural Network Classifier for Variable Stars with Novelty Detection Capability
Authors: Tsang Benny T.-H. , Schultz William C. 
Published: May 2019

Abstract
Common variable star classifiers are built with the singular goal of producing the correct class labels, leaving much of the multi-task capability of deep neural networks unexplored. We present a periodic light curve classifier that combines a recurrent neural network autoencoder for unsupervised feature extraction and a dual-purpose estimation network for supervised classification and novelty detection. The estimation network optimizes a Gaussian mixture model in the reduced-dimension feature space, where each Gaussian component corresponds to a variable class. An estimation network with a basic structure of a single hidden layer attains a cross-validation classification accuracy of ∼99%, which is on par with the conventional workhorses, random forest classifiers. With the addition of photometric features, the network is capable of detecting previously unseen types of variability with precision 0.90, recall 0.96, and an F
1 score of 0.93. The simultaneous training of the autoencoder and estimation network is found to be mutually beneficial, resulting in faster autoencoder convergence, as well as superior classification and novelty detection performance. The estimation network also delivers adequate results even when optimized with pre-trained autoencoder features, suggesting that it can readily extend existing classifiers to provide added novelty detection capabilities.
Multiscale estimation of the field-aligned current density
Authors: Bunescu Costel , Vogt Joachim , Marghitu Octav , Blagau Adrian 
Published: May 2019

Abstract. Field-aligned
currents (FACs) in the magnetosphere–ionosphere (M–I)
system exhibit a range of spatial and temporal scales that are
linked to key dynamic coupling processes. To disentangle the scale
dependence in magnetic field signatures of auroral FACs and to
characterize their geometry and orientation, Bunescu et al. (2015)
introduced the multiscale FAC analyzer framework based on minimum
variance analysis (MVA) of magnetic time series segments. In the
present report this approach is carried further to include in the
analysis framework a FAC density scalogram, i.e., a multiscale
representation of the FAC density time series. The new technique is
validated and illustrated using synthetic data consisting of
overlapping sheets of FACs at different scales. The method is
applied to Swarm data showing both large-scale and quiet aurora as
well as mesoscale FAC structures observed during more disturbed
conditions. We show both planar and non-planar FAC structures as
well as uniform and non-uniform FAC density structures. For both
synthetic and Swarm data, the multiscale analysis is applied by two
scale sampling schemes, namely the linear and logarithmic scanning of the FAC
scale domain. The local FAC density is compared
with the input FAC density for the synthetic data, whereas for the
Swarm data we cross-check the results with well-established single- and
dual-spacecraft techniques. All the multiscale information
provides a new visualization tool for the complex FAC signatures
that complements other FAC analysis tools.
Identification of secondary fatty alcohols in atmospheric aerosols in temperate forests
Authors: Miyazaki Yuzo , Gowda Divyavani , Tachibana Eri , Takahashi Yoshiyuki , Hiura Tsutom 
Published: May 2019

Abstract. Fatty alcohols (FAs) are major components of surface
lipids (waxes) and can act as surface-active organic aerosols in the
atmosphere, influencing chemical reactions, particle lifetimes, and the
formation of cloud droplets and ice nuclei. However, studies on the
composition and source of the FAs in atmospheric aerosols are very limited.
In this study, we identified five secondary FAs (SFAs) with C27 and
C29 from aerosol samples collected throughout 1 year at two different deciduous forest sites in Japan. Fatty diols, such as
n-heptacosan-5,10-diol, were identified in atmospheric aerosols for the first
time. Among the identified SFAs, n-nonacosan-10-ol was the most abundant
compound, followed by n-nonacosan-5-10-diol at both of the forest sites.
Concentrations of the SFAs exhibited distinct seasonal variation, with
pronounced peaks during the growing season at each forest site. The SFAs
showed significant correlation with sucrose, which is used as a molecular
tracer of pollen. A significant fraction of the SFAs was attributed to the
submicrometer particles in the growing season. The results indicate that
they originated mostly from plant waxes and could be used as useful tracers
for primary biological aerosol particles.
ESCOLHA ALIMENTAR DE UNIVERSITÁRIOS DE UMA UNIVERSIDADE DO PARANÁ
Authors: LIMA Karine Aparecida , SCHWARZ Kélin , MENEGASSI Bruna , MACHADO Tatiane Winkler Marques , SALDAN Paula Chuproski 
Published: May 2019

O objetivo do estudo foi avaliar a escolha alimentar de usuários universitários beneficiados com o auxílio alimentação. Foi realizado um estudo transversal em uma Unidade Produtora de Refeição de um restaurante universitário da cidade de Guarapuava-PR, com 175 participantes. Foi avaliado o Índice de Massa Corporal (IMC) auto referido e a avaliação da escolha alimentar deu-se por meio de um cartão e do registro fotográfico dos pratos, para verificar a presença dos grupos de alimentos no almoço de cinco dias. De acordo com o IMC, a maior parte dos participantes encontrava-se em estado de eutrofia. Em relação a escolha alimentar, 96,5% (n=169) dos participantes escolheram alimentos do grupo dos cereais, raízes e tubérculos nos cinco dias avaliados, 60,5% (n=106) escolheram alimentos do grupo das leguminosas (feijão) todos os dias da semana e 27,4% (n=48) dos participantes escolheram esse alimento 3 a 4 vezes na semana, já a escolha de alimentos do grupo das hortaliças durante cinco dias da semana foi de 90,2% (n=158), do grupo das carnes 84,5% (n=148) dos participantes escolheram alimentos desse grupo todos os dias da semana e 11,4% (n=20) de 3 a 4 vezes. Em relação ao grupo de doces e açúcares aqui representado pelas sobremesas, 72,5% (n=127) dos participantes não escolheram alimentos desse grupo e 20,5% (n=36) escolheram 1 a 2 vezes na semana. A maioria dos participantes realizam escolhas saudáveis, o que mostra que o auxílio alimentação tem sido um ponto positivo para a alimentação dos comensais beneficiados.
On a system of nonlinear wave equations of Kirchhoff type with a strong dissipation
Authors: Wu Shun-Tang , Tsai Long-Yi 
Published: May 2019

The initial boundary value problem for systems of nonlinear wave equations of Kirchhoff type with strong dissipation in a bounded domain is considered. We prove the local existence of solutions by Banach fixed point theorem and
blow-up of solutions by energy method. Some estimates for the life span of solutions are given.
Un análisis de la eficiencia de municipios turísticos españoles
Authors: Bendodo Benasayag Elías , Fernández Gámez Manuel Ángel , Sánchez Serrano José Ramón 
Published: May 2019

El objetivo de este estudio es conocer qué factores exógenos condicionan la eficiencia de los municipios con una marcada orientación turística. Este estudio es una de las pocas publicaciones basadas en la eficiencia de municipios turísticos. A diferencia de la mayoría de las investigaciones que evalúan la eficiencia municipal en general, se cree que este documento contribuye a la literatura relacionada ofreciendo ideas a los municipios turísticos relativamente ineficientes sobre la mejora de la eficiencia.
The objective of this study is to know which exogenous factors condition the efficiency of the municipalities with tourist orientation. This study is one of the few publications based on the efficiency of tourism municipalities. Unlike most of the research that assesses municipal efficiency in general, it is believed that this document contributes to related literature by offering ideas to relatively inefficient tourism municipalities about improving efficiency.
Hybrid quantum systems based on magnonics
Authors: Lachance-Quirion Dany , Tabuchi Yutaka , Gloppe Arnaud , Usami Koji , Nakamura Yasunobu 
Published: May 2019

Abstract
Engineered quantum systems enabling novel capabilities for computation and sensing have blossomed in the last decade. Architectures benefiting from combining complementary physical systems have emerged as promising approaches for quantum technologies. A new class of hybrid quantum systems based on collective spin excitations in ferromagnetic materials has led to the diverse set of platforms outlined in this review article. The coherent interaction between microwave cavity modes and spin-wave modes is presented as a key ingredient for the development of more complex hybrid systems. Indeed, quanta of excitation of the spin-wave modes, called magnons, can also interact coherently with optical photons, phonons, and superconducting qubits in the fields of cavity optomagnonics, cavity magnomechanics, and quantum magnonics, respectively. Notably, quantum optics experiments in magnetically-ordered solid-state systems are within reach thanks to quantum magnonics. Applications of hybrid quantum systems based on magnonics for quantum information processing and quantum sensing are briefly outlined.
Combined application of pharamcokinetic DCE‐MRI and IVIM‐DWI could improve detection efficiency in early diagnosis of ductal carcinoma in situ
Authors: Tao Wei‐jing , Zhang Hui‐xin , Zhang Lian‐mei , Gao Feng , Huang Wei , Liu Yan , Zhu Yan , Bai Gen‐ji 
Published: May 2019

AbstractPurposeDuctal carcinoma in situ (DCIS) is a precursor of invasive ductal breast carcinoma (IDC). This study aimed to use pharamcokinetic dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) for the early diagnosis of DCIS.MethodsForty‐seven patients, including 25 with DCIS (age: 28–70 yr, mean age: 48.7 yr) and 22 with benign disease (age: 25–67 yr, mean age: 43.1 yr) confirmed by pathology, underwent pharamcokinetic DCE‐MRI and IVIM‐DWI in this study. The quantitative parameters Ktrans, Kep, Ve, Vp, and D, f, D* were obtained by processing of DCE‐MRI and IVIM‐DWI images with Omni‐Kinetics and MITK‐Diffusion softwares, respectively. Parameters were analyzed statistically using GraphPad Prism and MedCalc softwares.ResultsAll low‐grade DCIS lesions demonstrated mass enhancement with clear boundaries, while most middle‐grade and high‐grade DCIS lesions showed non‐mass‐like enhancement (NMLE). DCIS lesions were significantly different from benign lesions in terms of Ktrans, Kep, and D (t = 5.959, P < 0.0001; t = 5.679, P < 0.0001; and t = 5.629, P < 0.0001, respectively). The AUC of Ktrans, Kep, D and the combined indicator of Ktrans, Kep, and D were 0.936, 0.902, 0.860, and 0.976, respectively. There was a significant difference in diagnostic efficacy only between D and the combined indicator (Z = 2.408, P = 0.016).ConclusionDCE‐MRI and IVIM‐DWI could make for the early diagnosis of DCIS, and reduce the misdiagnosis of DCIS and over‐treatment of benign lesions.
Multiple Superwettable Nanofiber Arrays Prepared by a Facile Dewetting Strategy via Controllably Localizing a Low‐Energy Compound
Authors: Tang Zhongxue , He Meijin , Bian Ruixin , Duan Zhongfeng , Luan Kang , Hou Jiexin , Hu Binbin , Jiang Lei , Liu Huan 
Published: May 2019

AbstractSuperwettable solid surfaces have attracted substantial research interest due to their outstanding performance. Various approaches have been developed for preparing superwettable surfaces via constructing a highly textured surface roughness and/or altering the surface free energy. Here, a facile dewetting strategy is proposed to produce multiple superwettabilities on copper hydroxide nanofiber arrays (Cu(OH)2‐NFAs) by controlling the localized state of low‐energy silicone oil. It is proposed that both the capillary forces along each nanofiber and the evaporation of the octane solvent contribute to the localization of the silicone oil in the NFAs. By varying the concentration of the silicone oil, its localized state changes from a scattered discontinuous distribution to a continuous thin/thick film, which leads to variations in the surface energy and surface roughness. Consequently, Cu(OH)2‐NFAs with superhydrophilicity, superhydrophobicity with both high and low adhesion, and super slippery properties are prepared. Notably, a very small amount of silicone oil can alter the surface wettability of the Cu(OH)2‐NFAs from superhydrophilic to superhydrophobic, which is attributable to the migration of silicone oil to the top of the nanofibers during the dewetting process. These results will provide new insights on the facile fabrication of functional surfaces with multiple superwettabilities.
A Universal Converse Voltage Process for Triggering Transition Metal Hybrids In Situ Phase Restruction toward Ultrahigh‐Rate Supercapacitors
Authors: Guo Wei , Yu Chang , Li Shaofeng , Song Xuedan , Huang Huawei , Han Xiaotong , Wang Zhao , Liu Zhibin , Yu Jinhe , Tan Xinyi , Qiu Jieshan 
Published: May 2019

AbstractDefect engineering holds great promise for precise configuration of electrode materials for dramatically enhanced performance in the field of energy storage, but the high energy/large time cost and lack of control involved in this process represent a serious limit to its use. In response, a low‐energy‐cost and ultrafast universal converse voltage process is developed to effectively activate the capacitive performance of transition metal compounds integrated on carbon fiber paper, including Co‐, Ni‐, Mn‐, Fe‐, and Cr‐based hybrids. As a representative example, this process triggers a phase conversion from cobalt hydroxide to electric‐field‐activated CoOOH (EA‐CoOOH), leading to the formation of molecular structure with abundant defects, lattice disorders, and connecting holes, responsible for an enhanced performance within 10 min at room temperature. Moreover, the retained Co2+ in EA‐CoOOH results in increased activity, confirmed by density functional theory calculations. Consequently, these EA‐CoOOH hybrids deliver a capacitance value of 832 F g−1 at a current density of 1 A g−1 and exhibit a retention rate up to 78% (649 F g−1) at a super‐large current density of 200 A g−1. This technology paves a way for ultrafast configuration/modulation of defects on advanced materials toward application in the fields of energy and catalysis.
Rhodium‐Catalyzed ortho‐Arylation of (Hetero)aromatic Acids
Authors: Weber Philip , Rank Christian K. , Yalcinkaya Enis , Dyga Marco , van Lingen Tim , Schmid Rochus , Patureau Frederic W. , Gooßen Lukas J. 
Published: May 2019

AbstractRhodium acetate effectively promotes the carboxylate‐directed ortho‐arylation of (hetero)aromatic carboxylates with aryl bromides. The main advantage of this phosphine‐free, redox‐neutral method arises from its efficiency in assembling biologically meaningful electron‐rich arylpyridines, which are problematic substrates in known C−H arylations using Pd, Ru, and Ir catalysts.magnified image
Directed Assembly of Nanoparticle Threshold‐Selector Arrays
Authors: Speckbacher Maximilian , Rinderle Michael , Kaiser Waldemar , Osman Eiman A. , Chryssikos Domenikos , Cattani‐Scholz Anna , Gibbs Julianne M. , Gagliardi Alessio , Tornow Marc 
Published: May 2019

AbstractThe directed assembly of ordered arrays of cubic silver nanoparticles featuring distinct electrical threshold‐switching characteristics is reported. Threshold selectors are key elements for nonvolatile resistive random‐access‐memory architectures, as they suppress sneak path currents in crosspoint arrays. Nanocubes are site‐selectively immobilized on a TiO2‐coated silicon surface via a complementary molecular surface functionalization of nanoparticles and substrate based on a Cu(I)‐catalyzed alkyne‐azide cycloaddition without any physical template. Electrical characterization of individual silver nanocubes by conductive‐probe atomic force microscopy reveals pronounced and reproducible threshold‐switching behavior, featuring ultralow OFF currents below 1 pA, steep turn‐on slopes of <50 mV dec−1 and ON‐OFF ratios in excess of 103. Numerical simulation of Ag‐ion migration dynamics in the TiO2 electrolyte using a kinetic Monte Carlo model supports a switching mechanism based on conductive filament formation from Ag nanoclusters, and their reversible rupture in the low‐voltage regime. Assembled Ag nanocube threshold selectors are proposed for applications in memristive memory architectures, in particular for future highly integrated 3D circuitry.
Pilot‐scale experimental studies on ethanol purification by cyclic stripping
Authors: Maleta Vladimir N. , Bedryk Olesja , Shevchenko Alexander , Kiss Anton A. 
Published: May 2019

AbstractCyclic distillation is a proven process intensification method for enhanced separation of various mixtures. It uses an alternative operating mode based on separate phase movement which leads to important practical advantages (vs conventional mode) such as increased column throughput, lower equipment cost (using much less trays at the same reflux ratio) and reduced energy requirements by 20–35% (smaller reflux ratio at the same number of stages), and better separation performance (up to three times). However, if the impurities to be separated are in very low amounts in the feed then distillation is not favorable from an energy use viewpoint. This article is the first to report the practical performance of a continuous process for ethanol purification by air stripping using a cyclic mode of operation, a novel process that avoids the costs of distillation. The purification of ethanol food grade (96.4 vol%) from volatile impurities (0.5 vol%) such as esters, aldehydes, and alcohols, is carried out in a hydro‐selective column with five stages. The lightweight impurities are removed from a stream that is the head fraction of a distillation column. This is usually a waste stream amounting to 3–6% of the plant production rate. By concentrating the stream with impurities, more ethanol is produced such that the losses are reduced to only 1–1.5% of the plant capacity. Based on the experimental results presented in this work, a process consisting of two air stripping columns using cyclic operation is proposed for industrial implementation.
Differences in flowering time maintain species boundaries in a continental radiation ofViburnum
Authors: Spriggs Elizabeth L. , Schlutius Caroline , Eaton Deren A. , Park Brian , Sweeney Patrick W. , Edwards Erika J. , Donoghue Michael J. 
Published: May 2019

PremiseWe take an integrative approach in assessing how introgression and Pleistocene climate fluctuations have shaped the diversification of the coreLentagoclade ofViburnum, a group of five interfertile species with broad areas of sympatry. We specifically tested whether flowering time plays a role in maintaining species isolation.MethodsRAD‐seq data for 103 individuals were used to infer the species relationships and the genetic structure within each species. Flowering times were compared among species on the basis of historical flowering dates documented by herbarium specimens.ResultsWithin each species, we found a strong relationship between flowering date and latitude, such that southern populations flower earlier than northern ones. In areas of sympatry, the species flower in sequence rather than simultaneously, with flowering dates offset by ≥9 d for all species pairs. In two cases it appears that the offset in flowering times is an incidental consequence of adaptation to differing climates, but in the recently diverged sister speciesV. prunifoliumandV. rufidulum, we find evidence that reinforcement led to reproductive character displacement. Long‐term trends suggest that the two northern‐most species are flowering earlier in response to recent climate change.ConclusionsWe argue that speciation in theLentagoclade has primarily occurred through ecological divergence of allopatric populations, but differences in flowering time were essential to maintain separation of incipient species when they came into secondary contact. This combination of factors may underlie diversification in many other plant clades.
N‐Heterocyclic Carbene Catalyzed Radical Coupling of Aldehydes with Redox‐Active Esters
Authors: Song Runjiang , Chi Yonggui Robin 
Published: May 2019

AbstractN‐Heterocyclic carbene catalyzed radical reactions are challenging and underdeveloped. In a recent study, Ohmiya, Nagao and co‐workers found that aldehyde carbonyl carbon centers can be coupled with alkyl radicals under NHC catalysis. An elegant aspect of this study is the use of a redox‐active carboxylic ester that behaves as an single‐electron oxidant to convert the Breslow intermediate into a radical adduct and concurrently release an alkyl radical intermediate as a reaction partner.