bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase delay of short-period tsunamis in the density-stratified compressible ocean over the elastic Earth
Authors: Sandanbata Osamu , Watada Shingo , Ho Tung-Cheng , Satake Kenji 
Published: May 2021

SUMMARY
Tsunamis are often modelled as surface gravity waves of incompressible homogenous water propagating over a rigid seafloor. Previous studies have noted that when computing long-period tsunamis travelling at trans-oceanic distances with dominant periods of thousands of seconds, we need to consider four factors that are not included in the surface gravity wave theory: compressibility of seawater, density stratification of oceans, elasticity of the Earth and gravitational potential change associated with the tsunami motion. However, their effects on short-period tsunamis with dominant periods below 1000 s have not been examined. Here, we investigate how the four factors influence short-period tsunamis. Theoretical analyses and 1-D simulations using phase speeds of different tsunami models indicate that the resultant phase delay of short-period tsunamis becomes apparent after ∼1000 km propagation, mainly because of the first three factors. We then introduce a new phase correction method for dispersive short-period tsunamis with consideration of period-dependent ray paths and apply it to a 2-D simulation of a short-period tsunami from a submarine volcanic earthquake near Japan in 2015. The correction of the traveltime of a synthetic waveform by including the four factors amounts to ∼40 s at a distant station 1430 km away from the source, whereas the effects of the four factors on the waveforms are negligibly small at stations &lt; ∼500km from the source. The observed traveltime at the ocean bottom pressure (OBP) gauge with a sampling interval at 15 s of the distant station can be explained only when these factors are incorporated into synthetic waveforms, indicating the effects due to the four factors are detectable by high-sampling OBP gauges that are deployed over broad oceanic regions.
Automatic slowness vector measurements of seismic arrivals with uncertainty estimates using bootstrap sampling, array methods and unsupervised learning
Authors: Ward J , Thorne M , Nowacki A , Rost S 
Published: May 2021

SUMMARYHorizontal slowness vector measurements using array techniques have been used to analyse many Earth phenomena from lower mantle heterogeneity to meteorological event location. While providing observations essential for studying much of the Earth, slowness vector analysis is limited by the necessary and subjective visual inspection of observations. Furthermore, it is challenging to determine the uncertainties caused by limitations of array processing such as array geometry, local structure, noise and their effect on slowness vector measurements. To address these issues, we present a method to automatically identify seismic arrivals and measure their slowness vector properties with uncertainty bounds. We do this by bootstrap sampling waveforms, therefore also creating random sub arrays, then use linear beamforming to measure the coherent power at a range of slowness vectors. For each bootstrap sample, we take the top N peaks from each power distribution as the slowness vectors of possible arrivals. The slowness vectors of all bootstrap samples are gathered and the clustering algorithm DBSCAN (Density-Based Spatial Clustering of Applications with Noise) is used to identify arrivals as clusters of slowness vectors. The mean of slowness vectors in each cluster gives the slowness vector measurement for that arrival and the distribution of slowness vectors in each cluster gives the uncertainty estimate. We tuned the parameters of DBSCAN using a data set of 2489 SKS and SKKS observations at a range of frequency bands from 0.1 to 1 Hz. We then present examples at higher frequencies (0.5–2.0 Hz) than the tuning data set, identifying PKP precursors, and lower frequency by identifying multipathing in surface waves (0.04–0.06 Hz). While we use a linear beamforming process, this method can be implemented with any beamforming process such as cross correlation beamforming or phase weighted stacking. This method allows for much larger data sets to be analysed without visual inspection of data. Phenomena such as multipathing, reflections or scattering can be identified automatically in body or surface waves and their properties analysed with uncertainties.
Toward Establishing Integrated, Comprehensive, and Sustainable Meningitis Surveillance in Africa to Better Inform Vaccination Strategies
Authors: Kwambana-Adams Brenda Anna , Cohen Adam L , Hampton Lee , Nhantumbo Aquino Albino , Heyderman Robert S , Antonio Martin , Bita Andre , Mwenda Jason Mathiu 
Published: May 2021

Abstract
Large populations across sub-Saharan Africa remain at risk of devastating acute bacterial meningitis epidemics and endemic disease. Meningitis surveillance is a cornerstone of disease control, essential for describing temporal changes in disease epidemiology, the rapid detection of outbreaks, guiding vaccine introduction and monitoring vaccine impact. However, meningitis surveillance in most African countries is weak, undermined by parallel surveillance systems with little to no synergy and limited laboratory capacity. African countries need to implement comprehensive meningitis surveillance systems to adapt to the rapidly changing disease trends and vaccine landscapes. The World Health Organization and partners have developed a new investment case to restructure vaccine-preventable disease surveillance. With this new structure, countries will establish comprehensive and sustainable meningitis surveillance systems integrated with greater harmonization between population-based and sentinel surveillance systems. There will also be stronger linkage with existing surveillance systems for vaccine-preventable diseases, such as polio, measles, yellow fever, and rotavirus, as well as with other epidemic-prone diseases to leverage their infrastructure, transport systems, equipment, human resources and funding. The implementation of these concepts is currently being piloted in a few countries in sub-Saharan Africa with support from the World Health Organization and other partners. African countries need to take urgent action to improve synergies and coordination between different surveillance systems to set joint priorities that will inform action to control devastating acute bacterial meningitis effectively.
On the Sensitivity and Specificity of Postmortem Upper Respiratory Tract Testing for SARS-CoV-2
Authors: Hall Jennifer A , Harris Ross J , Emmett Hannah E , Lowe Belinda , Singanayagam Anika , Twohig Katherine A , Zaidi Asad , Kall Meaghan , Zambon Maria , Dabrera Gavin 
Published: May 2021

Abstract

Background
Postmortem testing can improve our understanding of the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) if sufficiently sensitive and specific.

Methods
We investigated the postmortem sensitivity and specificity of reverse transcriptase polymerase chain reaction (PCR) testing on upper respiratory swabs using a dataset of everyone tested for SARS-CoV-2 before and after death in England, 1 March to 29 October 2020. We analyzed sensitivity in those with a positive test before death by time to postmortem test. We developed a multivariate model and conducted time-to-negativity survival analysis. For specificity, we analyzed those with a negative test in the week before death.

Results
Postmortem testing within a week after death had a sensitivity of 96.8% if the person had tested positive within a week before death. There was no effect of age, sex, or specimen type on sensitivity, but individuals with coronavirus disease 2019 (COVID-19)–related codes on their death certificate were 5.65 times more likely to test positive after death (95% confidence interval, 2.31–13.9). Specificity was 94.2%, increasing to 97.5% in individuals without COVID-19 on the death certificate.

Conclusion
Postmortem testing has high sensitivity (96.8%) and specificity (94.2%) if performed within a week after death and could be a useful diagnostic tool.
What Are the Challenges to Peace? A Workshop on Conflict Analysis to Understand Middle East Politics
Authors: Suárez-Collado Ángela , Sierra Javier 
Published: May 2021

AbstractThis article presents an innovative teaching and learning method based on collaborative and inquiry-based learning implemented in a Middle East Politics course. It consists of a series of online workshops in which students work in teams to analyze three different current conflicts in the region: Libya, Syria, and the Israeli-Palestinian. The aim of this method was twofold: on the one hand, to create a reflexive setting to help students acquire the most comprehensive possible knowledge about the conflict's causes and dynamics, the concerns and priorities of the main actors involved or affected by the conflict, and major obstacles to its resolution; on the other hand, to enhance a set of key cognitive, skill-based, and affective learning outcomes, which are essential skills in Political Science and other related areas such as International Studies. This study shows that teaching and learning methodologies based on collaborative and inquiry-based learning are suitable tools to facilitate the understanding of multifaceted, complex realities and to generate new perspectives and views on unfamiliar contexts. This research also suggests that facilitating the active involvement of students in their self-learning can contribute to successful online teaching and to foster the acquisition of key cognitive, skill-based, and affective learning outcomes.
Why They Fight: How Perceived Motivations for Military Service Shape Support for the Use of Force
Authors: Krebs Ronald R , Ralston Robert , Rapport Aaron 
Published: May 2021

Abstract
What shapes public support for military missions? Existing scholarship points to, on the one hand, individuals’ affiliations and predispositions (such as political partisanship and gender), and, on the other hand, factors that shape a rational cost–benefit analysis (notably, mission objectives, the prospects for victory, and the magnitude and distribution of costs). We argue that public opinion is also shaped by beliefs about why soldiers voluntarily enlist. Using novel survey data and an experiment, deployed to a nationally representative sample of Americans, we test how four conceptions of soldiering affect support for a prospective military operation. We find, in observational data, that believing that a soldier is a good citizen or patriot bolsters support for the mission, while believing that a soldier has enlisted because he wants the material benefits of service or has “no other options” undermines support. These results support our causal argument: Americans’ attitudes toward military missions are shaped by their perception of whether the soldier has consented to deployment rather than by feelings of social obligation. This article has implications for debates on the determinants of public support for military missions and the relationship between military service and citizenship in democracies.
Structure and biosynthesis of sorangipyranone — a new γ-dihydropyrone from the myxobacterial strain MSr12020
Authors: Okoth Dorothy A , Hug Joachim J , Mándi Attila , Kurtán Tibor , Garcia Ronald , Müller Rolf 
Published: May 2021

AbstractSorangipyranone was isolated as a novel natural product featuring a unique 2,3-dihydro-γ-4H-pyrone scaffold from cultures of the myxobacterial strain MSr12020. We report here the full structure elucidation of sorangipyranone by spectroscopic techniques including 2D NMR and high-resolution mass spectrometry together with the analysis of the biosynthetic pathway. Determination of the absolute configuration was performed by time-dependent density functional theory–electronic circular dichroism calculations and determination of the applicability of the Snatzke's helicity rule, to correlate the high-wavelength n→π* electronic circular dichroism (ECD) transition and the absolute configuration of the 2,3-dihydro-4H-γ-pyrone, was done by the analysis of low-energy conformers and the Kohn-Sham orbitals. Sorangipyranone outlines a new class of a γ-dihydropyrone-containing natural product comprised of malonyl-CoA-derived building blocks and features a unique polyketide scaffold. In silico analysis of the genome sequence of the myxobacterial strain MSr12020 complemented with feeding experiments employing stable isotope-labeled precursors allowed the identification and annotation of a candidate biosynthetic gene cluster that encodes a modular polyketide synthase assembly line. A model for the biosynthetic pathway leading to the formation of the γ-dihydropyrone scaffold is presented in this study.
The onset of jets in classical novae
Authors: McLoughlin Dominic , Blundell Katherine M , Lee Steven , McCowage Chris 
Published: May 2021

ABSTRACT
We present two further classical novae, V906 Car and V5668 Sgr, which show jets and accretion disc spectral signatures in their H α complexes throughout the first 1000 d following their eruptions. From extensive densely time-sampled spectroscopy, we measure the appearance of the first high-velocity absorption component in V906 Car, and the duration of the commencement of the main H α emission. We constrain the time taken for V5668 Sgr to transition to the nebular phase using [N ii] 6584 Å. We find these timings to be consistent with the jet and accretion disc model for explaining optical spectral line profile changes in classical novae, and discuss the implications of this model for enrichment of the interstellar medium.
Effects of the treatment of the mass quadrupole moment on ray-tracing applications for rapidly rotating neutron stars
Authors: Oliva G André , Frutos-Alfaro Francisco 
Published: May 2021

ABSTRACT
The Neutron Star Interior Composition Explorer (NICER) mission has provided a unique opportunity to constrain the equation of state of neutron stars by using the technique of pulse-profile modelling. This technique requires accurate and efficient ray-tracing, that in turn requires a robust representation of the space–time around a neutron star. Several exact and approximate metrics have been proposed, and used, to perform ray-tracing around neutron stars, with both moderate and fast rotation. In this paper, we perform a comparison between several of these metrics, when used for ray-tracing. We calculate the shape of the neutron star as seen by a distant observer using two different surface formulae, the thermal spectrum and pulse profiles from circular and crescent-shaped hotspots, for four configurations of pulsars with rotation rates ranging from 622 to 1000 Hz, and using both a moderate and a stiff equation of state to include realistic and extreme cases. We find small differences between the metrics for rotation frequencies starting at ${\sim}700\, \mathrm{Hz}$ that could theoretically be used for constraining the quadrupole moment or the space–time models. We also determine the practicality of use of each metric in larger-scale applications such as pulse-profile modelling.
Independent cosmological constraints from high-z H ii galaxies: new results from VLT-KMOS data
Authors: González-Morán Ana Luisa , Chávez Ricardo , Terlevich Elena , Terlevich Roberto , Fernández-Arenas David , Bresolin Fabio , Plionis Manolis , Melnick Jorge , Basilakos Spyros , Telles Eduardo 
Published: May 2021

ABSTRACT
We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(H β), and the velocity dispersion (σ) for H ii galaxies (HIIG). These results are based on new VLT-KMOS high spectral resolution observations of 41 high-z (1.3 ≤ z ≤2.6) HIIG combined with published data for 45 high-z and 107 z ≤0.15 HIIG, while the cosmological analysis is based on the MultiNest Markov Chain Monte Carlo (MCMC) procedure not considering systematic uncertainties. Using only HIIG to constrain the matter density parameter (Ωm), we find $\Omega _\mathrm{ m} = 0.244^{+0.040}_{-0.049}$ (stat), an improvement over our best previous cosmological parameter constraints, as indicated by a 37 per cent increase of the figure of merit. The marginalized best-fitting parameter values for the plane {Ωm; w0} = $\lbrace 0.249^{+0.11}_{-0.065}; -1.18^{+0.45}_{-0.41}\rbrace$ (stat) show an improvement of the cosmological parameters constraints by 40 per cent. Combining the HIIG Hubble diagram, the cosmic microwave background (CMB) and the baryon acoustic oscillation (BAO) probes yields Ωm = 0.298 ± 0.012 and w0 = −1.005 ± 0.051, which are certainly compatible – although less constraining – than the solution based on the joint analysis of Ia supernovae (SNIa), CMB and BAO measurements. An attempt to constrain the evolution of the dark energy with time (CPL model), using a joint analysis of the HIIG, CMB, and BAO measurements, shows a degenerate 1σ contour of the parameters in the {w0, wa} plane.
On the photometric metallicity of Oosterhoff-type I and II RRab stars
Authors: Jurcsik J , Hajdu G , Juhász Á 
Published: May 2021

ABSTRACT
We are revising the consistency of photometric metallicity formulae widely used for fundamental-mode RR Lyrae (RRab) variables, based on their V- and I-band light curves, published by Jurcsik & Kovács (1996) and Smolec (2005), respectively. 293 RRab variables belonging to 10 globular clusters, all simultaneously containing stars of both Oosterhoff types, are selected for this purpose. We find that, on average, the V-band formula results in higher estimated metallicities by about 0.05 dex than the I-band formula. Moreover, we detect a dependence on the Oosterhoff class of the variables for both formulae, as well. Using the V-band formula, Oo I stars are 0.05–0.10 dex more metal rich than Oo II stars of the same cluster. Although with less significance, but the I-band results indicate a reversed trend. Therefore, we surmise that the average difference we have found between the V- and I-band formulae is the consequence of the total sample being dominated by Oo I variables.
A fully-spectroscopic triple-source-plane lens: the Jackpot completed
Authors: Smith Russell J , Collett Thomas E 
Published: May 2021

ABSTRACT
We present a spectroscopic determination of the redshift of the second source in the Jackpot gravitational lens system J0946 + 1006, for which only a photometric estimate of zphot  =  2.41$^{+0.04}_{-0.21}$ has previously been available. By visually inspecting an archival Very Large Telescope (VLT) X-Shooter observation, we located a single emission line from the source in the H-band. Among the possible options, we find that this line is most likely to be [O iii] 5007 Å at zspec  =  2.035. Guided by this proposal, we were able to detect the faint C iii] 1907,1909 Å emission doublet in a deep VLT Multi Unit Spectroscopic Explorer datacube. The C iii] emission is spatially coincident with the brightest parts of the second Einstein ring, and strongly supports the redshift identification. The spectroscopic redshift is only marginally consistent with the photometric estimate. Re-examining the cosmological constraints from J0946 + 1006, the revised measurement favours less negative values of the dark energy equation-of-state parameter w; when combined with a cosmic microwave background prior, we infer w  =  −1.04 ± 0.20. The revised redshift does not significantly help to reconcile the small discrepancy in the image positions for the even more distant third source in J0946 + 1006.
Deep reinforcement learning for smart calibration of radio telescopes
Authors: Yatawatta Sarod , Avruch Ian M 
Published: May 2021

ABSTRACT
Modern radio telescopes produce unprecedented amounts of data, which are passed through many processing pipelines before the delivery of scientific results. Hyperparameters of these pipelines need to be tuned by hand to produce optimal results. Because many thousands of observations are taken during a lifetime of a telescope and because each observation will have its unique settings, the fine tuning of pipelines is a tedious task. In order to automate this process of hyperparameter selection in data calibration pipelines, we introduce the use of reinforcement learning. We test two reinforcement learning techniques, twin delayed deep deterministic policy gradient (TD3), and soft actor-critic, to train an autonomous agent to perform this fine tuning. For the sake of generalization, we consider the pipeline to be a black-box system where the summarized state of the performance of the pipeline is used by the autonomous agent. The autonomous agent trained in this manner is able to determine optimal settings for diverse observations and is therefore able to perform smart calibration, minimizing the need for human intervention.
Tidal tails in the disintegrating open cluster NGC 752
Authors: Bhattacharya Souradeep , Agarwal Manan , Rao Khushboo K , Vaidya Kaushar 
Published: May 2021

ABSTRACT
We utilize the robust membership determination algorithm, ML-MOC, on the precise astrometric and deep photometric data from Gaia Early Data Release 3 within a region of radius 5° around the centre of the intermediate-age Galactic open cluster NGC 752 to identify its member stars. We report the discovery of the tidal tails of NGC 752, extending out to ∼35 pc on either side of its denser central region and following the cluster orbit. From comparison with PARSEC stellar isochrones, we obtain the mass function of the cluster with a slope, χ = −1.26 ± 0.07. The high negative value of χ is indicative of a disintegrating cluster undergoing mass segregation. χ is more negative in the intra-tidal regions as compared to the outskirts of NGC 752. We estimate a present day mass of the cluster, $M\rm _{C} = 297\pm 10$ M⊙. Through mass-loss due to stellar evolution and tidal interactions, we further estimate that NGC 752 has lost nearly 95.2–98.5 per cent of its initial mass, Mi = 0.64–2 × 104 M⊙.
Analysis of Genomic DNA from Medieval Plague Victims Suggests Long-Term Effect of Yersinia pestis on Human Immunity Genes
Authors: Immel Alexander , Key Felix M , Szolek András , Barquera Rodrigo , Robinson Madeline K , Harrison Genelle F , Palmer William H , Spyrou Maria A , Susat Julian , Krause-Kyora Ben , Bos Kirsten I , Forrest Stephen , Hernández-Zaragoza Diana I , Sauter Jürgen , Solloch Ute , Schmidt Alexander H , Schuenemann Verena J , Reiter Ella , Kairies Madita S , Weiß Rainer , Arnold Susanne , Wahl Joachim , Hollenbach Jill A , Kohlbacher Oliver , Herbig Alexander , Norman Paul J , Krause Johannes 
Published: May 2021

Abstract
Pathogens and associated outbreaks of infectious disease exert selective pressure on human populations, and any changes in allele frequencies that result may be especially evident for genes involved in immunity. In this regard, the 1346-1353 Yersinia pestis-caused Black Death pandemic, with continued plague outbreaks spanning several hundred years, is one of the most devastating recorded in human history. To investigate the potential impact of Y. pestis on human immunity genes, we extracted DNA from 36 plague victims buried in a mass grave in Ellwangen, Germany in the 16th century. We targeted 488 immune-related genes, including HLA, using a novel in-solution hybridization capture approach. In comparison with 50 modern native inhabitants of Ellwangen, we find differences in allele frequencies for variants of the innate immunity proteins Ficolin-2 and NLRP14 at sites involved in determining specificity. We also observed that HLA-DRB1*13 is more than twice as frequent in the modern population, whereas HLA-B alleles encoding an isoleucine at position 80 (I-80+), HLA C*06:02 and HLA-DPB1 alleles encoding histidine at position 9 are half as frequent in the modern population. Simulations show that natural selection has likely driven these allele frequency changes. Thus, our data suggest that allele frequencies of HLA genes involved in innate and adaptive immunity responsible for extracellular and intracellular responses to pathogenic bacteria, such as Y. pestis, could have been affected by the historical epidemics that occurred in Europe.