bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observational constraints on the origin of the elements
Authors: Magg Ekaterina , Bergemann Maria , Serenelli Aldo , Bautista Manuel , Plez Bertrand , Heiter Ulrike , Gerber Jeffrey M. , Ludwig Hans-Günter , Basu Sarbani , Ferguson Jason W. , Gallego Helena Carvajal , Gamrath Sébastien , Palmeri Patrick , Quinet Pascal 
Published: March 2022

Context.The chemical composition of the Sun is required in the context of various studies in astrophysics, among them in the calculation of standard solar models (SSMs) used to describe the evolution of the Sun from the pre-main-sequence to its present age.Aims.In this work, we provide a critical re-analysis of the solar chemical abundances and corresponding SSMs.Methods.For the photospheric values, we employed new high-quality solar observational data collected with the IAG facility, state-of-the art non-equilibrium modelling, new oscillator strengths, and different atmospheric models, including the MARCS model, along with averages based on Stagger and CO5BOLD 3D radiation-hydrodynamics simulations of stellar convection. We performed new calculations of oscillator strengths for transitions in O I and N I. For O I, which is a critical element with regard to the interior models, calculations were carried out using several independent methods. We investigated our results in comparison with the previous estimates.Results.We find an unprecedented agreement between the new estimates of transition probabilities, thus supporting our revised solar oxygen abundance value. We also provide new estimates of the noble gas Ne abundance. In addition, we discuss the consistency of our photospheric measurements with meteoritic values, taking into account the systematic and correlated errors. Finally, we provide revised chemical abundances, leading to a new value proposed for the solar photospheric present-day metallicity of Z/X = 0.0225, which we then employed in SSM calculations. We find that the puzzling mismatch between the helioseismic constraints on the solar interior structure and the model can be resolved thanks to this new chemical composition.
Partially accreted crusts of neutron stars
Authors: Suleiman L. , Zdunik J. L. , Haensel P. , Fortin M. 
Published: March 2022

Context. Neutron stars in low-mass binary systems are subject to accretion when material originating from the companion star accumulates on the surface. In most cases, the justified and common assumption in studying the properties of the neutron star crust is the fully accreted crust approximation. However, observations of some X-ray transient sources indicate that the original crust has not been completely replaced by accreted material, but is partly composed of the compressed original crust.
Aims. The crust of an accreting neutron star beyond the fully accreted crust approximation was studied; a two-part (or hybrid) crust made of the original crust that is compressed and of the accreted material crashing onto it was reconstructed as a function of the accretion stage. The differences in the composition and energy sources for the fully accreted and hybrid crusts influence the cooling and transport properties.
Methods. A simple semi-empirical formula of a compressible liquid drop was used to compute the equation of state and composition of the hybrid crust. Calculations were based on the single-nucleus model, with a more accurate treatment of the neutron drip point. We compared the nuclear reactions triggered by compression in the original crust and in the accreted matter part of the hybrid crust. We discuss another crust compression astrophysical phenomenon related to spinning neutron stars.
Results. The compression of the originally catalyzed outer crust triggers exothermic reactions (electron captures and pycnonuclear fusions) that deposit heat in the crust. The heat sources are cataloged as a function of the compression until the fully accreted crust approximation is reached. The pressure at which neutron drip occurs is a nonmonotonic function of the depth, leading to a temporary neutron drip anomaly. The additional potential source of energy for partially accreted crusts is the occurrence of a density inversion phenomenon between some compressed layers.
Conclusions. The original crust of a neutron star cannot be neglected for the initial period of accretion, when the original crust is not fully replaced by the accreted matter. The amount of heat associated with the compression of the original crust is on the same order of magnitude as that from the sources acting in the accreted part of the hybrid crust.
Desorption of polycyclic aromatic hydrocarbons by cosmic rays
Authors: Dartois E. , Chabot M. , Koch F. , Bachelet C. , Bender M. , Bourçois J. , Duprat J. , Frereux J. , Godard M. , Hervé S. , Merk B. , Pino T. , Rojas J. , Schubert I. , Trautmann C. 
Published: March 2022

Context. The rate of sputtering and release of condensed species is an important aspect of interstellar chemistry, as is photodesorption for the most volatile species, because in the absence of such mechanisms the whole gas phase would have to condense in times often shorter than the lifetime of the considered medium, in particular for dense clouds. The recent detection of cyclic aromatic molecules by radioastronomy requires an understanding of the potential mechanisms supporting the rather high abundances observed.
Aims. We perform experiments to advance our understanding of the sputtering yield due to cosmic rays for very large carbonaceous species in the solid phase.
Methods. Thin films of perylene and coronene were deposited on a quartz cell microbalance and exposed to a 1.5 MeV N+ ion beam at the Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab, Orsay, France) and a 230 MeV 48Ca10+ ion beam at the GSI Helmholtzzentrum für Schwerionenforschung (GSI, Darmstadt, Germany). The mass loss was recorded as a function of the fluence for the N+ beam. The microbalance response was calibrated using Fourier transform infrared (FTIR) reflectance measurements of the produced films. In addition, the destruction cross-section of the same species was measured with the 48Ca10+ ion beam by in situ monitoring of the evolution of the infrared spectra of the bombarded films.
Results. We deduced the sputtering yield for perylene and coronene and their radiolysis destruction cross-sections. Combining these results with a cosmic ray astrophysical spectrum, we discuss the impact on the possible abundance that may originate from the sputtering of dust grains with these molecules as well as from polycyclic aromatic molecules when they are trapped in ice mantles.
Weak and strong domination on some graphs
Authors: Durgun Derya Doğan , Kurt Berna Lökçü 
Published: March 2022

Let G = (V(G), E(G)) be a graph and uvεE. A subset D ⊆ V of vertices is a dominating set if every vertex in V − D is adjacent to at least one vertex of D. The domination number is the minimum cardinality of a dominating set. Let u and v be elements of V. Then, u strongly dominates u and v weakly dominates u if (i)uvεE and (ii)deg(u) ≥ deg(v). A set D ⊆ V is a strong (weak) dominating set (sd-set)(wd-set) of G if every vertex in V − D is strongly dominated by at least one vertex in D. The strong (weak) domination number γs(γw) of G is the minimum cardinality of a sd-set (wd-set). In this paper, the strong and weak domination numbers of comet, double comet, double star and theta graphs are given. The theta graphs are important geometric graphs that have many applications, including wireless networking, motion planning, MST construction and real-time animation.
Diversification and Solvency II: the capital effect of portfolio swaps on non-life insurers
Authors: Sheehan Barry , Humberg Christian , Shannon Darren , Fortmann Michael , Materne Stefan 
Published: March 2022

AbstractDiversification plays a pivotal role under the risk-based capital regime of Solvency II. The new rules reward large and well-diversified insurance companies with relatively low capital requirements compared to those of small and specialised nature. To enhance diversification, insurance companies can adjust their strategy by engaging in mergers and acquisitions or new market entries. Alternatively, insurers can accept higher Solvency II capital requirements, displaying a competitive disadvantage and impeding future growth. This research proposes a Solvency II portfolio swap as a new diversification solution that allows small and specialised insurance companies to improve their diversification, and thus, mitigate their diversification disadvantage. The effect of such swaps is demonstrated through the use of two hypothetical insurance companies by swapping 20% of their portfolio over four different scenarios. The swap allowed for a 6% reduction in the Solvency Capital Requirement (SCR) and a maximum increase of the SCR coverage ratio of 17%. With Solvency II posited to stimulate further mergers and acquisitions within the European insurance market, this paper offers an alternative method for insurers to diversify their portfolio. Furthermore, it is suggested that the proposed alternative risk transfer method may improve insurance market competition within the EU by facilitating small and specialised insurers’ competitiveness.
Variation in upstream open reading frames contributes to allelic diversity in maize protein abundance
Authors: Gage Joseph L. , Mali Sujina , McLoughlin Fionn , Khaipho-Burch Merritt , Monier Brandon , Bailey-Serres Julia , Vierstra Richard D. , Buckler Edward S. 
Published: March 2022

Significance
Proteins are the machinery which execute essential cellular functions. However, measuring their abundance within an organism can be difficult and resource-intensive. Cells use a variety of mechanisms to control protein synthesis from mRNA, including short open reading frames (uORFs) that lie upstream of the main coding sequence. Ribosomes can preferentially translate uORFs instead of the main coding sequence, leading to reduced translation of the main protein. In this study, we show that uORF sequence variation between individuals can lead to different rates of protein translation and thus variable protein abundances. We also demonstrate that natural variation in uORFs occurs frequently and can be linked to whole-plant phenotypes, indicating that uORF sequence variation likely contributes to plant adaptation.
An allosteric HTRA1-calpain 2 complex with restricted activation profile
Authors: Rey Juliana , Breiden Maike , Lux Vanda , Bluemke Anika , Steindel Maike , Ripkens Kamilla , Möllers Bastian , Bravo Rodriguez Kenny , Boisguerin Prisca , Volkmer Rudolf , Mieres-Perez Joel , Clausen Tim , Sanchez-Garcia Elsa , Ehrmann Michael 
Published: March 2022

Significance
Classic serine proteases are synthesized as inactive precursors that are proteolytically processed, resulting in irreversible activation. We report an alternative and reversible mechanism of activation that is executed by an inactive protease. This mechanism involves a protein complex between the serine protease HTRA1 and the cysteine protease calpain 2. Surprisingly, activation is restricted as it improves the proteolysis of soluble tau protein but not the dissociation and degradation of its amyloid fibrils, a task that free HTRA1 is efficiently performing. These data exemplify a challenge for protein quality control proteases in the clearing of pathogenic fibrils and suggest a potential for unexpected side effects of chemical modulators targeting PDZ or other domains located at a distance to the active site.
Horizontal transmission enables flexible associations with locally adapted symbiont strains in deep-sea hydrothermal vent symbioses
Authors: Breusing Corinna , Genetti Maximilian , Russell Shelbi L. , Corbett-Detig Russell B. , Beinart Roxanne A. 
Published: March 2022

SignificanceIn marine ecosystems, transmission of microbial symbionts between host generations occurs predominantly through the environment. Yet, it remains largely unknown how host genetics, symbiont competition, environmental conditions, and geography shape the composition of symbionts acquired by individual hosts. To address this question, we applied population genomic approaches to four species of deep-sea hydrothermal vent snails that live in association with chemosynthetic bacteria. Our analyses show that environment is more important to strain-level symbiont composition than host genetics and that symbiont strains show genetic variation indicative of adaptation to the distinct geochemical conditions at each vent site. This corroborates a long-standing hypothesis that hydrothermal vent invertebrates affiliate with locally adapted symbiont strains to cope with the variable conditions characterizing their habitats.
Synchronous spiking of cerebellar Purkinje cells during control of movements
Authors: Sedaghat-Nejad Ehsan , Pi Jay S. , Hage Paul , Fakharian Mohammad Amin , Shadmehr Reza 
Published: March 2022

Significance
The information that one region of the brain transmits to another is usually viewed through the lens of firing rates. However, if the output neurons could vary the timing of their spikes, then, through synchronization, they would spotlight information that may be critical for control of behavior. Here we report that, in the cerebellum, Purkinje cell populations that share a preference for error convey, to the nucleus, when to decelerate the movement, by reducing their firing rates and temporally synchronizing the remaining spikes.
Conformational snapshots of the bacitracin sensing and resistance transporter BceAB
Authors: George Natasha L. , Schilmiller Anthony L. , Orlando Benjamin J. 
Published: March 2022

Significance
Many gram-positive organisms have evolved an elegant solution to sense and resist antimicrobial peptides that inhibit cell-wall synthesis. These organisms express an unusual “Bce-type” adenosine triphosphate–binding cassette (ABC) transporter that recognizes complexes formed between antimicrobial peptides and lipids involved in cell-wall biosynthesis. In this work, we provide the first structural snapshots of a Bce-type ABC transporter trapped in different conformational states. Our structures and associated biochemical data provide key insights into the novel target protection mechanism that these unusual ABC transporters use to sense and resist antimicrobial peptides. The studies described herein set the stage to begin developing a comprehensive molecular understanding of the diverse interactions between antimicrobial peptides and conserved resistance machinery found across most gram-positive organisms.
Verb stem alternation in Gongduk
Authors: Gerber Pascal 
Published: March 2022

Abstract
This paper provides a first overview of verb stem alternation in Gongduk (eastern Bhutan, Trans-Himalayan). Verb stem alternation in Gongduk is conditioned both by morphophonology and by grammatical categories. This paper presents both the morphophonologically transparent as well as the phonologically opaque, paradigmatic stem alternation. The analysis provided in this paper identifies seven verb classes and a small number of irregular verbs. Additionally, this paper provides some diachronic observations on Gongduk verb stems and shows that different stem classes of Gongduk preserve derivational morphology (valence, direction) with cognates in other branches of the language family. Gongduk therefore provides important evidence for the historical investigation of derivational morphology and verb stem alternation in Trans-Himalayan.
RF MEMS filter based on dual liquid variations
Authors: Habbachi Nizar , Besbes Kamel 
Published: March 2022

Abstract
This paper discusses the behavior of RF MEMS tunable microwave filter. We have modeled the distribution of magnetic field and electric current density in order to reveal the comportment of each device and to evaluate the relation between the frequency response and the microwave performances. From several modelling and simulations, we catch the resonance phenomenon for magnetic and electric fields at different conditions. Hence, in order to develop a reconfigurable MEMS ensuring a function of tunable band-pass filters, we have identified conditions allowing to vary the resonance frequency from Fres = 0.42 GHz to Fres = 1.85 GHz ensuring a large total variation of Tr = 340.5%. The structure is fabricated using SU-8 resin for circulating microchannels and sealing layers. The extracted parameters from measurements results and retro-simulation reveal a diminution of the total tuning range.
Picoliter liquid operations in nanofluidic channel utilizing an open/close valve with nanoscale curved structure mimicking glass deflection
Authors: Sano Hiroki , Kazoe Yutaka , Morikawa Kyojiro , Kitamori Takehiko 
Published: March 2022

Abstract
Microfluidics has downscaled to nanofluidics to achieve state-of-the-art analyses at single/countable molecules level. In nanofluidic analytical devices, switching and partitioning reagents in nanochannels without contamination are essential operations. For such operations, we have developed a nanochannel open/close valve utilizing elastic glass deformation. However, owing to a rectangular-shaped nanospace, sample leakage due to diffusion through the remaining open space in the closed valve occurs and causes contamination. Herein, we propose a fabrication method of nanoscale curved structure resembling the glass deflection shape to develop the nanofluidic valve for switching and partitioning operations in nanochannels. After fabricating a four-stepped rectangular nanospace by electron beam lithography and dry etching, the space was plastically deformed using an impulsive force by pressing the chamber more than 20 000 times. A smoothly curved structure with a high aspect ratio of 750 (75 μm width and 100 nm depth) fitting the glass deflection shape, which has been difficult for conventional methods, was successfully fabricated. Utilizing a valve with the curved structure, the solute leakage through the closed valve was reduced to less than 0.5% with a 94% decreased diffusion flux compared to previous valve with the rectangular-shaped structure. The developed valve realized switching of 72 pl reagents in a nanochannel with a response time of 0.4 s, which is sufficient for nanofluidic-chromatography, and it correctly worked even after an interval of 30 min, which is required for repeatable nanofluidic analyses. The newly developed valve will contribute to realizing versatile nanofluidic analytical devices.
Data-driven model-free adaptive sliding mode control for electromagnetic linear actuator
Authors: Gu Chaofan , Tan Cao , Li Bo , Lu Jiayu , Wang Geng , Chi Xuwen 
Published: March 2022

Abstract
A data-driven model-free adaptive sliding mode control (MFASMC) method is proposed to tackle the problems of inaccurate model and time-varying parameters of a micro electro-magnetic linear actuator system, considering the dependence of existing model-based control methods on the system dynamics model and the impact of unmodeled dynamics on the control performance. Firstly, the pseudo-gradient concept in the model-free adaptive control (MFAC) framework is used to transform the electromagnetic linear actuator dynamics model, which is difficult to obtain parameters accurately, into a full-format dynamic linearized data model, the dependence of the controller on the electromagnetic linear actuator model is reduced. To compensate for the effects of unknown perturbations, an improved discrete sliding mode exponential convergence law is introduced to derive a new composite control algorithm based on the pseudo partial derivative estimator, which improves the robustness of the control system. Then, the convergence of the control error and the stability of the system are demonstrated by theoretical analysis. The results show that the proposed MFASMC reduces the 10 mm step response time of the electromagnetic linear actuator by 46.3% and 25.3% compared with proportional-integral-derivative control (PID) and MFAC. The phase lag time and root-mean-square error of MFASMC under sinusoidal conditions are 0.8 ms, 0.178 mm respectively, and the steady-state error does not exceed 0.05 mm. The experimental and simulation results keep the error within 5%, the proposed control algorithm has good trajectory tracking response speed and control accuracy, and has good robustness to system uncertainty and external force disturbance.
Origin of photo-enhanced hysteretic electrical conductance in nanostructured silicon-based heterojunction
Authors: Chakrabarty Sudipta , Das Jayoti , Minhaz Hossain Syed 
Published: March 2022

Abstract
Photo-enhanced hysteretic I–V curves have been observed under reverse bias in a p-i-n structure containing electrochemically etched nanostructured silicon (Si) sandwiched between p-Si and n-type a-Si:H layers. These curves have been found to depend on intensity of incident illumination and structural morphology of the nanostructured Si layer. The conductance in trace path is lower than that in retrace path. Charge transport mechanism in this structure has been interpreted using microscopic description of charge trapping and detrapping in the defect states present at the interface of nanocrystalline silicon core and oxide shell in the active layer. An applied voltage dependent probability distribution of trapping and detrapping has been calculated in light of classical random walk problem. The trapping/detrapping of charges leading to development/destruction of potential barriers in the path of charge flow shows an analogy with the river bed deposition/erosion. The rate of trapping has been considered to depend on the empty defect states whereas the rate of detrapping depends on the already filled defects. Moreover, the rate of both trapping and detrapping is expected to depend on the charge flow rate. All these considerations lead the I–V relations for trace and retrace paths in reverse bias fitting nicely with experimental I–V loops. The observed peaks in the voltage dependent dynamic conductance in trace and retrace paths have been explained as a consequence of development and destruction of two barriers in the active layer for electrons and holes separately. Best fit values of the fitting parameters indicates that the trace path is dominated by holes whereas the retrace path is dominated by electronic transport. The difference in mobility of electron and hole leads to different trapping and detrapping rates in the two paths resulting in the observed hysteresis.
Impact of N2 admixture on the synthesis of graphitic carbon nanoparticles using atmospheric-pressure microwave plasma
Authors: Heo Seonil , Lim TaeGyeong , Kim Byeong Soo , Suk Ji Won , Bak Moon Soo 
Published: March 2022

Abstract
Atmospheric-pressure microwave plasma was utilized for catalyst-free gas-phase synthesis of graphitic carbon nanoparticles by adding CH4 to a mixture of N2 and He. The impact of N2 on the formation of the graphitic carbon nanoparticles was analyzed by increasing the N2 flow rate from 0 to 20 slpm and decreasing the He flow rate from 40 to 20 slpm simultaneously. The addition of N2 altered the morphology of the carbon nanoparticles to obtain flatter and larger shapes. Furthermore, carbon nanoparticles synthesized with N2 possessed more graphitic structures with higher C/O ratios and larger crystallite sizes than those synthesized without N2. The analysis of gas compositions at thermodynamic equilibrium states demonstrated that CN and HCN were the dominant precursor species when N2 was added. The presence of N atoms or N-containing species seem to have a synergistic effect combined with H atoms on the formation of the graphitic carbon nanoparticles.