bluuebunny/crossref_metadata_2025_split huggingface dataset:
xCOLD GASS and xGASS: Radial metallicity gradients and global properties on the star-forming main sequence
Authors: Lutz K. A. , Saintonge A. , Catinella B. , Cortese L. , Eisenhauer F. , Kramer C. , Moran S. M. , Tacconi L. J. , Vollmer B. , Wang J. 
Published: February 2021

Context. The xGASS and xCOLD GASS surveys have measured the atomic (H I) and molecular gas (H2) content of a large and representative sample of nearby galaxies (redshift range of 0.01 < z < 0.05).
Methods. We present optical longslit spectra for a subset of the xGASS and xCOLD GASS galaxies to investigate the correlation between radial metallicity profiles and cold gas content. In addition to previous data, this paper presents new optical spectra for 27 galaxies in the stellar mass range of 9.0 ≤ log M⋆ [M⊙] ≤10.0.
Methods. The longslit spectra were taken along the major axis of the galaxies, allowing us to obtain radial profiles of the gas-phase oxygen abundance (12 + log(O/H)). The slope of a linear fit to these radial profiles is defined as the metallicity gradient. We investigated correlations between these gradients and global galaxy properties, such as star formation activity and gas content. In addition, we examined the correlation of local metallicity measurements and the global H I mass fraction.
Results. We obtained two main results: (i) the local metallicity is correlated with the global H I mass fraction, which is in good agreement with previous results. A simple toy model suggests that this correlation points towards a ‘local gas regulator model’; (ii) the primary driver of metallicity gradients appears to be stellar mass surface density (as a proxy for morphology).
Conclusions. This work comprises one of the few systematic observational studies of the influence of the cold gas on the chemical evolution of star-forming galaxies, as considered via metallicity gradients and local measurements of the gas-phase oxygen abundance. Our results suggest that local density and local H I mass fraction are drivers of chemical evolution and the gas-phase metallicity.
Multi-instrumental view of magnetic fields and activity of ϵ Eridani with SPIRou, NARVAL, and TESS
Authors: Petit P. , Folsom C. P. , Donati J.-F. , Yu L. , do Nascimento J.-D. , Jeffers S. V. , Marsden S. C. , Morin J. , Vidotto A. A. 
Published: February 2021

Aims. We report on observations of the active K2 dwarf ϵ Eridani based on contemporaneous SPIRou, NARVAL and TESS data obtained over two months in late 2018, when the activity of the star was reported to be in a non-cyclic phase.
Methods. Near-infrared (NIR) spectropolarimetry was obtained using SPIRou over four nights in late September, while visible spectropolarimetry was collected with NARVAL over 20 nights, spread between 18 September and 07 November. We first recovered the fundamental parameters of the target from both visible and NIR spectral fitting. The large-scale magnetic field was investigated from polarimetric data. From unpolarized spectra, we estimated the total magnetic flux through Zeeman broadening of magnetically sensitive NIR lines and the chromospheric emission using the CaII H&K lines. The photometric monitoring, secured with TESS between 19 October and 15 November, is modelled with pseudo-periodic Gaussian process regression.
Results. Fundamental parameters of ϵ Eridani derived from visible and NIR wavelengths provide us with consistent results, which also agree with published values. We report a progressive increase of macroturbulence towards larger NIR wavelengths. Zeeman broadening of individual lines highlights an unsigned surface magnetic field Bmono = 1.90 ± 0.13 kG, with a filling factor f = 12.5 ± 1.7% (unsigned magnetic flux Bf = 237 ± 36 G). The large-scale magnetic field geometry, chromospheric emission and broadband photometry display clear signs of non-rotational evolution over the course of data collection. Characteristic decay times deduced from the light curve and longitudinal field fall in the range 30–40 days, while the characteristic timescale of surface differential rotation, as derived through the evolution of the magnetic geometry, is equal to 57 ± 5 days. The large-scale magnetic field exhibits a combination of properties not observed previously for ϵ Eridani, with a surface field among the weakest previously reported, but this field is also mostly axisymmetric, and is dominated by a toroidal component.
EFFECTS OF FUEL TEMPERATURE-SHAPING FUNCTIONS ON XENON OSCILLATIONS
Authors: Walker Erik , Godfrey Andrew , Stimpson Shane , Collins Benjamin 
Published: February 2021

In coupled multiphysics simulations, single pin-averaged values are typically used to describe the temperature, power, and burnup within a given fuel pin. However, since xenon oscillations are largely driven by fuel temperatures, radially dependent quantities have been implemented in the Virtual Environment for Reactor Applications. These radial-shaping functions are based on Zernike polynomial expansions and allow information to pass effectively between codes with differing spatial meshes. This work examines the effects of radial fuel temperature-shaping functions on the behavior of axial xenon oscillations.
A test problem was developed from full-core, multi-cycle depletions using as-built fuel data. The center 25 assemblies of the full-core case were used to test the radial-shaping function by inducing an axial xenon oscillation using an instantaneous control rod movement. The test case was run with and without the radial shapes, and each component was also run individually. Including the shaping functions significantly impacted the xenon oscillations for this problem; the magnitude and period of the oscillations were altered, and large pin power and soluble boron differences were observed. Testing each component individually showed that the radial fuel temperature-shaping function had the largest effect.
IMPROVED ANISOTROPIC LINEAR SOURCE FORMULATION FOR MULTIPHYSICS PROBLEMS
Authors: Herring Nicholas F. , Fitzgerald Andrew , Kochunas Brendan , Downar Thomas 
Published: February 2021

This work seeks to extend an existing formulation of the method of characteristics with linear source approximation for problems with dynamic cross sections. The previous formulation eliminated cross section dependence of precomputed coefficients for systems with an isotropic source. The method is extended to include a formulation for spatially flat anisotropic scattering that eliminates cross section dependence of precomputed coefficients without adding additional operations; increasing efficiency in multiphysics simulations where cross sections can be subject to change.
The new formulation is implemented in the MPACT code and tested on two problems: 3D transport assembly calculations using MPACT’s 2D/1D method and a 3D assembly with T/H feedback using MPACT’s 2D/1D method coupled with COBRA-TF. This work demonstrates that the new linear source formulation allows for the number of mesh elements to be significantly reduced while maintaining accuracy, leading to shorter run-times for 3D cases with fixed cross sections, and substantial reduction of memory usage for 3D cases with fixed cross sections. The multiphysics calculations show similar runtimes for the same accuracy with significant reduction of memory. For similar accuracy, the method proved effective in reducingmemory usage by, on average, 30% for 3D problems and 21% for multiphysics problems.
BENCHMARKING OF THE SERPENT 2 MONTE CARLO CODE FOR FUSION NEUTRONICS APPLICATIONS
Authors: Valentine A. , Colling B. , Worrall R. , Leppänen J. 
Published: February 2021

Analyses of radiation fields resulting from a deuterium-tritium (DT) plasma in fusion devices is a critical input to the design and validation of many aspects of the reactor design, including, shielding, material lifetime and remote maintenance requirements/scheduling. Neutronics studies, which perform in-depth analysis are typically performed using radiation transport codes such as MCNP, TRIPOLI, Serpent, FLUKA and OpenMC. The Serpent 2 Monte-Carlo code, developed by VTT in Finland, is the focus of this work which seeks to benchmark the code for fusion applications. The application of Serpent 2 in fusion specific analysis requires validation of the codes performance in an energy range, and a geometrical description, which significantly differs to conventional nuclear fission analysis, for which the code was originally developed.
A Serpent model of the Frascati Neutron Generator (FNG) Helium Cooled Pebble Bed (HCPB) mock up experiment has been prepared and the calculated results compared against experimental data, as well as the reference Monte Carlo code MCNP. The analysis is extended to a model of DEMO with HCPB blanket concept. For this model, the flux, nuclear heating, tritium production and DPA are calculated, all of which are integral nuclear responses in fusion reactor analysis. In general, a very good agreement is demonstrated for both of the benchmarks, with any discrepancies pinpointed to different physics models implemented.
EFFECT OF THE UNIFORM FISSION SOURCE METHOD ON LOCAL POWER VARIANCE IN FULL CORE SERPENT CALCULATION
Authors: Bilodid Yurii , Leppänen Jaakko 
Published: February 2021

One of challenges of the Monte Carlo full core simulations is to obtain acceptable statistical variance of local parameters throughout the whole reactor core at a reasonable computation cost. The statistical variance tends to be larger in low-power regions. To tackle this problem, the Uniform-Fission-Site method was implemented in Monte Carlo code MC21 and its effectiveness was demonstrated on NEA Monte Carlo performance benchmark. The very similar method is also implemented in Monte Carlo code Serpent under the name Uniform Fission Source (UFS) method.
In this work the effect of UFS method implemented in Serpent is studied on the BEAVRS benchmark which is based on a real PWR core with relatively flat radial power distribution and also on 3x3 PWR mini-core simulated with thermo-hydraulic and thermo-mechanic feedbacks. It is shown that the application of the Uniform Fission Source method has no significant effect on radial power variance but equalizes axial distribution of variance of local power.
THE TCA BENCHMARK FOR VALIDATION OF TEMPERATURE FEEDBACK CALCULATIONS
Authors: van der Marck Steven C. , Asquith Nicola L. 
Published: February 2021

The TCA benchmark was investigated as a possible candidate for validation of temperature feedback calculations. This benchmark has low-enriched uranium fuel, light water moderation and reflection, and a temperature range of 20–60 °C. The use of three different nuclear data libraries was considered, viz. ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0. Since the results were not as good as hoped for, additional studies were performed to identify the cause(s) of discrepancies.
The benchmark values depend on a choice of delayed neutron data, so it was investigated whether this could be the cause of discrepancies. Also, an assessment was made based on critical configurations only, i.e. avoiding the use of delayed neutron data, whether the calculations exhibit a bias in relation to the benchmark in the results for the effect of temperature. Indications were found that such a bias exists.
It is concluded that the choice of delayed neutron data has a significant effect on the benchmark values themselves. The use of three major nuclear data libraries leads to a range of benchmark values for each configuration, rather than one value. Also, one has to take into account the possibility of a bias in the calculation of temperature effects. It is not clear at this point what the cause of the bias is.
SYSTEMATIC ANALYSIS OF MULTIVARIATE SCENARIOS USING ADVANCED CLUSTERING METHODS
Authors: Marc Ernoult , Sylvain David , Doligez Xavier , Jiali Liang , Nicolas Thiolliere , Lea Tillard 
Published: February 2021

The continuous improvement of fuel cycle simulators in conjunction with the increase of computing capacities have led to a new scale of scenario studies. Taking into consideration multiple variable parameters and observing their effect on multiple evaluation criteria, these scenario studies regroup several thousands of trajectories paving the different possible values for multiple operational parameters. If global methods like sensitivity analysis allow extracting useful information from these groups of trajectories, they only provide average and global values.
In this work we present a new method to analyze these groups of trajectories while keeping some localization in the information. Based on principal component analysis, clustering method have been implemented in order to mathematically extract, from the ensemble of trajectories simulated for a scenario study, subgroups of trajectories that have similar behaviors. Typical trajectories, representative of these subgroups, are then determined. The application of this new method on a sample scenario for two different output, the total amount of transuranic elements within the fuel cycle and the number of time the MOX fuel could not be built during the simulated time, is presented. The comparison of the results between the two analyses shows that the method allows good clustering for continuous and regular outputs but struggle with discrete highly non-linear ones.
RESULTS OF VERA APPLICATION TO THE AP1000® PWR STARTUP
Authors: Franceschini F. , Salazar D. , Godfrey A. 
Published: February 2021

This paper describes the application of the Virtual Environment for Reactor Applications, VERA, under development by the Consortium for Advanced Simulation of LWRs (CASL) to the core physics analysis of the AP1000 PWR.
The AP1000 PWR features an advanced first core with radial and axial heterogeneities which provides significant enhancements compared to traditional first cores, allowing best fuel usage and short transition to the equilibrium cycle with subsequent fuel reloads. These core advanced features can pose some challenges to the core physics tools making application of VERA to the AP1000 PWR first core especially relevant to qualify VERA performance.
This paper focuses on the qualification efforts at hot zero power conditions, where Monte-Carlo reference solutions have also been established. In particular, the paper focuses on the comparison of the predictions obtained with VERA for the four AP1000 units that recently started up with the measured values. It is shown that there is excellent agreement between VERA and the key reactor physics parameters measured during the AP1000 startup.
EXPERIMENTAL DETERMINATION OF THE ZERO POWER TRANSFER FUNCTION OF THE AKR-2
Authors: Hübner Sebastian , Knospe Alexander , Viebach Marco , Lange Carsten , Hurtado Antonio 
Published: February 2021

The transfer function is a basic characteristic of every nuclear reactor. It describes how a perturbation at a given place and time influences the neutron flux. In case of a known perturbation, the determination of characteristic reactor parameters is possible. The present paper shows an experimental method to determine the gain of the zero-power reactor transfer function (ZPTF) of the AKR-2 reactor at TU Dresden and the comparison to the theoretical shape of the ZPTF derived from kinetic parameters simulated with MCNP. For the experiments, a high-precision linear motor axis is used to insert an oscillating perturbation acting at frequencies smaller than the lower bound of the plateau region of the ZPTF. For higher frequencies, a rotating absorber is used. This device emulates an absorber of variable strength. The reactor response is detected with a He-3 counter.The data evaluation shows good agreement between measured and corresponding theoretical values of the gain of the ZPTF.
Synthesis of Imidazole and Histidine-Derived Cross-Linkers as Analogues of GOLD and Desmosine
Authors: Bilitewski Ursula , Laschat Sabine , Schädel Nicole , Icik Esra , Martini Maike , Altevogt Luca , Ramming Isabell , Greulich Andreas , Baro Angelika 
Published: February 2021

AbstractAmino acid derivatives with a central cationic heterocyclic core (e.g., imidazolium) are biologically relevant cross-linkers of proteins and advanced glycation end (AGE) products. Here, imidazolium-containing cross-linkers were synthesized from imidazole or histidine by N-alkylation employing aspartate- and glutamate-derived mesylates as key step. Biological investigations were carried out to probe the biocompatibility of these compounds.
Probabilistic pragmatics explains gradience and focality in natural language quantification
Authors: van Tiel Bob , Franke Michael , Sauerland Uli 
Published: February 2021

SignificanceTheoretical linguistics postulates abstract structures that successfully explain key aspects of language. However, the precise relation between abstract theoretical ideas and empirical data from language use is not always apparent. Here, we propose to empirically test abstract semantic theories through the lens of probabilistic pragmatic modeling. We consider the historically important case of quantity words (e.g., “some,” “all”). Data from a large-scale production study seem to suggest that quantity words are understood via prototypes. But based on statistical and empirical model comparison, we show that a probabilistic pragmatic model that embeds a strict truth-conditional notion of meaning explains the data just as well as a model that encodes prototypes into the meaning of quantity words.
Unfolded and intermediate states of PrP play a key role in the mechanism of action of an antiprion chaperone
Authors: Petrosyan Rafayel , Patra Shubhadeep , Rezajooei Negar , Garen Craig R. , Woodside Michael T. 
Published: February 2021

Significance
Many diseases involve the propagation of misfolded proteins as in prion diseases. Compounds that can inhibit conversion into misfolded conformers exist, but their mechanism of action remains poorly understood. By observing the effects of the polymeric antiprion pharmacological chaperone pentosan polysulfate on the folding of single prion protein molecules, we find that interactions with partially and fully unfolded states play an important role. A comparison to previous results for a chaperone with very different chemical properties suggests that antiprion agents help to prevent conversion by interacting with the protein when it unfolds from the native structure during the conversion process. Unfolded states may, therefore, be fruitful targets for developing more effective therapeutic inhibitors of prion and prion-like conversion.
Real-time measurements of aminoglycoside effects on protein synthesis in live cells
Authors: Aguirre Rivera Javier , Larsson Jimmy , Volkov Ivan L. , Seefeldt A. Carolin , Sanyal Suparna , Johansson Magnus 
Published: February 2021

Significance
To address the public health challenges caused by the spread of antibiotic resistance, it is critical to enhance our understanding of the mechanisms of action of these compounds. In the present study, we use superresolved single-molecule tracking techniques, to investigate the effect of three aminoglycoside drugs on protein synthesis kinetics directly inside live bacterial cells. Our results imply that these drugs do not completely inhibit bacterial protein synthesis, but only make it slower. Hence, the bactericidal effect of these drugs is likely due to a disturbed, rather than inhibited, protein synthesis process.
Sea spray aerosol concentration modulated by sea surface temperature
Authors: Liu Shang , Liu Cheng-Cheng , Froyd Karl D. , Schill Gregory P. , Murphy Daniel M. , Bui T. Paul , Dean-Day Jonathan M. , Weinzierl Bernadett , Dollner Maximilian , Diskin Glenn S. , Chen Gao , Gao Ru-Shan 
Published: February 2021

Significance
Climate models use pre-industrial atmosphere as the reference to evaluate the impacts of human activities on the Earth’s radiation balance. Sea spray aerosols (SSA) are the key component in the relatively pristine preindustrial conditions that substantially affect model calculations. Currently, the abundance of SSA is poorly constrained. In particular, studies on the influence of sea surface temperature on SSA production have shown disparate results. This uncertainty arises from limited field measurements, especially over remote oceans. Our global aircraft measurements over the remote Pacific and Atlantic Oceans show that higher sea surface temperature enhances the production of SSA. Updating the current parameterization in global models using our observational constraints will improve the estimate of atmospheric SSA budget and human-induced climate change.
Elastic amplification of the Rayleigh–Taylor instability in solidifying melts
Authors: Jambon-Puillet Etienne , Piéchaud Matthieu Royer , Brun P.-T. 
Published: February 2021

Significance
Patterns resulting from successive far-from-equilibrium processes are common in nature. Yet, they are challenging to investigate, model, and translate to engineering owing to their complexity coupled to fluctuating developmental conditions. Here we introduce a comparatively simpler system combining a fluidic instability and large solid deformations in solidifying melts to produce soft solids with complex surface geometry. We fully rationalize this different kind of pattern comprising elongated hair-like features using the framework of continuum mechanics. Our work is relevant to the broad range of problems where mechanical deformations and solidification are concomitant and paves the way for the use of multistep moldless approaches for the assembly of complex materials.
Influence of a COVID-19 vaccine’s effectiveness and safety profile on vaccination acceptance
Authors: Kaplan Robert M. , Milstein Arnold 
Published: February 2021

Significance
Acceptance of vaccines has been on the decline in recent years. Despite encouraging early results for coronavirus vaccine trials, achieving herd immunity requires substantial uptake. We presented scenarios varying vaccine efficacy, minor side effects, and severe reactions to a sample representative of the US population. Vaccine acceptance improved when the efficacy increased beyond 70%. Respondents were unaffected by the probability of minor side effects, such as a sore arm or fever lasting 24 h. The chances of accepting the vaccine were lower when the probability of serious adverse reactions was 1/100,000 in contrast to 1/million or 1/100 million. A replication showed that the results were largely unchanged following the public announcement that the vaccines were 95% effective.
Active control of plasmon-induced transparency with large tunability and high Q-factor in graphene-black phosphorus hybrid system
Authors: Han Li , Wang Lin , Xing Huaizhong , Chen Xiaoshuang 
Published: February 2021

Abstract
Plasmon-induced transparency phenomena in the mid-infrared caused by the coupling behavior between dipole (bright element) and higher-order modes (dark element) in graphene as well as black phosphorus (BP) nanoribbons are investigated. The transparent windows can be adjusted flexibly by varying the carrier concentration of graphene and BP. It is also shown that the carrier mobility and refractive index of the substrate are the key factors affecting destructive interference. Obvious group delays are obtained near the transparent windows so that the slow light effect can be achieved. Our results allow a better understanding of efficient exploration of surface plasmons with integrated properties of building blocks from a family of two-dimensional materials, with the aim of expanding both photonic bands and functionalities.