bluuebunny/crossref_metadata_2025_split huggingface dataset:
Misaligned Twin Molecular Outflows from the Class 0 Protostellar Binary System VLA 1623A Unveiled by ALMA
Authors: Hara Chihomi , Kawabe Ryohei , Nakamura Fumitaka , Hirano Naomi , Takakuwa Shigehisa , Shimajiri Yoshito , Kamazaki Takeshi , Di Francesco James , Machida Masahiro N. , Tamura Motohide , Saigo Kazuya , Matsumoto Tomoaki , Tomida Kengo 
Published: April 2021

Abstract
We present the results of ALMA observations toward the low-mass Class 0 binary system VLA 1623Aab in the Ophiuchus molecular cloud in 12CO, 13CO, and C18O(2–1) lines. Our 12CO (J = 2–1) data reveal that the VLA 1623 outflow consists of twin spatially overlapped outflows/jets. The redshifted northwestern jet exhibits three cycles of wiggle with a spatial period of 1360 ± 10 au, corresponding to a time period of 180 yr. The wiggle-like structure is also found in the position–velocity (PV) diagram, showing an amplitude in the velocity of about 0.9 km s−1. Both the period and velocity amplitude of the wiggle are roughly consistent with those expected from the binary parameters, i.e., the orbital period (460 ± 20 yr) and the Keplerian velocity (2.2 km s−1). Our 13CO and C18O images show a dense gas nature in the two centimeter/millimeter sources, VLA 1623B and W, and its relation to the outflows, and strongly support the previous interpretation that both are shocked cloudlets. The driving sources of the twin molecular outflows are, therefore, likely to be the VLA 1623Aab binary. The outflow axes of the two molecular outflows are estimated to be inclined by 70° to each other across the plane of sky, implying that protostellar disks are also misaligned by

. Such nature together with a small binary separation of 34 au in one of the youngest protobinary systems seems difficult to explain by disk fragmentation in quiescent environments. Other effects such as turbulence probably play roles.
General Relativistic Neutrino-driven Turbulence in One-dimensional Core-collapse Supernovae
Authors: Boccioli Luca , Mathews Grant J. , O’Connor Evan P. 
Published: April 2021

Abstract
Convection and turbulence in core-collapse supernovae (CCSNe) are inherently three-dimensional (3D) in nature. However, 3D simulations of CCSNe are computationally demanding. Thus, it is valuable to modify simulations in spherical symmetry to incorporate 3D effects using some parametric model. In this paper, we report on the formulation and implementation of general relativistic neutrino-driven turbulent convection in the spherically symmetric core-collapse supernova code GR1D. This is based upon the recently proposed method of Simulated Turbulence in Reduced Dimensionality (STIR) in Newtonian simulations from Couch et al. (2020). When the parameters of this model are calibrated to 3D simulations, we find that our general relativistic formulation of STIR requires larger turbulent eddies to achieve a shock evolution similar to the original STIR model. We also find that general relativity may alter the correspondence between progenitor mass and successful versus failed explosions.
Probing the Disk–Corona Systems and Broad-line Regions of Changing-look Quasars with X-Ray and Optical Observations
Authors: Jin Xiangyu , Ruan John J. , Haggard Daryl , Gingras Marie-Joëlle , Hountalas Joseph , MacLeod Chelsea L. , Anderson Scott F. , Doan Anh , Eracleous Michael , Green Paul J. , Runnoe Jessie C. 
Published: April 2021

Abstract
“Changing-look” quasars are a new class of highly variable active galactic nuclei that have changed their spectral type over surprisingly short timescales of just a few years. The origin of this phenomenon is debated, but is likely to reflect some change in the accretion flow. To investigate the disk–corona systems in these objects, we measure optical/UV–X-ray spectral indices (

α

OX

) and Eddington ratios (

λ

Edd

) of 10 previously discovered changing-look quasars at two or more epochs. By comparing these data with simulated results based on the behavior of X-ray binaries, we find possible similarities in spectral indices below the 1% Eddington ratio. We further investigate the Eddington ratios of changing-look quasars before and after their spectral type changes, and find that changing-look quasars cross the 1% Eddington ratio boundary when their broad emission lines disappear/emerge. This is consistent with the disk-wind model as the origin of broad emission lines.
On Single-point Inversions of Magnetic Dipole Lines in the Corona
Authors: Judge Philip , Casini Roberto , Paraschiv Alin Razvan 
Published: April 2021

Abstract
Prompted by a recent paper by Dima and Schad, we reconsider the problem of inferring magnetic properties of the corona using polarimetric observations of magnetic dipole (M1) lines. Dima and Schad point to a potential source of degeneracy in a formalism developed by Plowman, which under some circumstances can lead to the solution being under-determined. Here we clarify the nature of the problem. Its resolution lies in solving for the scattering geometry using the elongation of the observed region of the corona. We discuss some conceptual problems that arise when casting the problem for inversion in the observer’s reference frame, and satisfactorily resolve difficulties identified by Plowman, Dima, and Schad.
Multiscale Solar Wind Turbulence Properties inside and near Switchbacks Measured by the Parker Solar Probe
Authors: Martinović Mihailo M. , Klein Kristopher G. , Huang Jia , Chandran Benjamin D. G. , Kasper Justin C. , Lichko Emily , Bowen Trevor , Chen Christopher H. K. , Matteini Lorenzo , Stevens Michael , Case Anthony W. , Bale Stuart D. 
Published: April 2021

Abstract
The Parker Solar Probe (PSP) routinely observes magnetic field deflections in the solar wind at distances less than 0.3 au from the Sun. These deflections are related to structures commonly called “switchbacks” (SBs), whose origins and characteristic properties are currently debated. Here, we use a database of visually selected SB intervals—and regions of solar wind plasma measured just before and after each SB—to examine plasma parameters, turbulent spectra from inertial to dissipation scales, and intermittency effects in these intervals. We find that many features, such as perpendicular stochastic heating rates and turbulence spectral slopes are fairly similar inside and outside of SBs. However, important kinetic properties, such as the characteristic break scale between the inertial to dissipation ranges differ inside and outside these intervals, as does the level of intermittency, which is notably enhanced inside SBs and in their close proximity, most likely due to magnetic field and velocity shears observed at the edges. We conclude that the plasma inside and outside of an SB, in most of the observed cases, belongs to the same stream, and that the evolution of these structures is most likely regulated by kinetic processes, which dominate small-scale structures at the SB edges.
A Harsh Test of Far-field Scrambling with the Habitable-zone Planet Finder and the Hobby–Eberly Telescope
Authors: Kanodia Shubham , Halverson Samuel , Ninan Joe P. , Mahadevan Suvrath , Stefansson Gudmundur , Roy Arpita , Ramsey Lawrence W. , Bender Chad F. , Janowiecki Steven , Cochran William D. , Diddams Scott A. , Drory Niv , Endl Michael , Ford Eric B. , Hearty Fred , Metcalf Andrew J. , Monson Andrew , Robertson Paul , Schwab Christian , Terrien Ryan C , Wright Jason T. 
Published: April 2021

Abstract
The Habitable-zone Planet Finder (HPF) is a fiber-fed precise radial velocity (RV) spectrograph at the 10 m Hobby–Eberly Telescope (HET). Due to its fixed-altitude design, the HET pupil changes appreciably across a track, leading to significant changes of the fiber far-field illumination. HPF’s fiber scrambler is designed to suppress the impact of these illumination changes on the RVs—but the residual impact on the RV measurements has yet to be probed on-sky. We use GJ 411, a bright early type (M2) M dwarf to probe the effects of far-field input trends due to these pupil variations on HPF RVs. These large changes (∼2x) in the pupil area and centroid present a harsh test of HPF’s far-field scrambling. Our results show that the RVs are effectively decoupled from these extreme far-field input changes due to pupil centroid offsets, attesting to the effectiveness of the scrambler design. This experiment allows us to test the impact of these changes with large pupil variation on-sky, something we would not easily be able to do at a conventional optical telescope. While the pupil and illumination changes expected at these other telescopes are small, scaling from our results enables us to estimate and bound these effects, and show that they are controllable even for the new and next generation of RV instruments in their quest to beat down instrumental noise sources toward the goal of a few

cm

s

−
1

.
Detectability of “Merger-nova” Emission from a Long-lived Magnetar in Short Gamma-Ray Bursts
Authors: Yuan Yong , Lü Hou-Jun , Yuan Hao-Yu , Ma Shuai-Bing , Lei Wei-Hua , Liang En-Wei 
Published: April 2021

Abstract
One possible progenitor of short gamma-ray bursts (GRBs) is thought to be from a double neutron star (NS) merger, and the remnant of such a merger may be a supramassive NS, which is supported by rigid rotation and through its survival of hundreds of seconds before collapsing into a black hole (BH). If this is the case, an optical/infrared transient (namely merger-nova) is generated from the ejected materials and it is powered by radioactive decay from r-process, spin-down energy from a supramassive NS, as well as the magnetic wind from a newborn BH. In this paper, we systematically search for the signature of a supramassive NS central engine by analyzing the X-ray emission of short GRBs with internal plateau observed by Swift, and we find that five candidates of short GRBs have such a feature with redshift measurement. Then, we calculate the possible merger-nova emission from those candidates given the typical model parameters by considering the above three energy sources, and compare its brightness with the sensitivity of some optical telescopes. We find that the merger-nova emission of GRB 060801 in K-, r-, and U-bands with variations of M
ej (10−4–10−2
M
⊙), κ (0.1–10 cm2 g−1), and β (0.1–0.3) is very difficult to detect using the Vera C. Rubin, Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), the Zwicky Transient Facility, and the Roman Space Telescope (Roman), except for the case of large ejecta mass M
ej = 10−2
M
⊙. However, we are very hopeful to detect the merger-nova emission of GRBs 090515, 100625A, and 101219A using more sensitive instruments, such as Vera C. Rubin, Pan-STARRS, and Roman. Moreover, the merger-nova emission of GRB 160821B is bright enough to detect in our calculations, and it is also consistent with current real observations of merger-nova emission.
Relating the Properties of Chromospheric Condensation to Flare Energy Transported by Thermal Conduction
Authors: Ashfield W. H. , Longcope D. W. 
Published: April 2021

Abstract
Chromospheric condensation is a brief episode of downflow often accompanying energy release and evaporation in a solar flare. While this component of a flare reflects the energy release process only indirectly, it can be observed at high spatial and temporal resolution, even from the ground. It appears in spectroscopic observations of cooler lines, formed below ∼105 K, as a redshift that peaks and decays after less than 1 minute. In order to use this signature to infer characteristics of solar flare energy release, it is important to establish quantitative relationships with properties of the condensation. The initial investigation reported here does so after restricting consideration to energy transport via thermal conduction into a simplified, stratified chromosphere. We develop an analytical expression for the decay of a condensation propagating into a stratified atmosphere. This model provides a relationship between shock velocity and preshock density structure. We also use one-dimensional gasdynamic simulations to explore the dynamics of these shocks as they penetrate into the stratified chromosphere. We find that the peak downflow speed primarily reflects the energy flux into the chromosphere, while the product of this velocity and the redshift duration is proportional to the preshock density scale height as H ≃ 0.6u
0
τ.
Impact of Dark Photon Emission on Massive Star Evolution and Pre-supernova Neutrino Signal
Authors: Sieverding A. , Rrapaj E. , Guo G. , Qian Y.-Z. 
Published: April 2021

Abstract
We study the effects of additional cooling due to the emission of a dark matter candidate particle, the dark photon, on the final phases of the evolution of a 15 M
⊙ star and resulting modifications of the pre-supernova neutrino signal. For a substantial portion of the dark photon parameter space the extra cooling speeds up Si burning, which results in a reduced number of neutrinos emitted during the last day before core collapse. This reduction can be described by a systematic acceleration of the relevant timescales and the results can be estimated semi-analytically in good agreement with the numerical simulations. Outside the semi-analytic regime we find more complicated effects. In a narrow parameter range, low-mass dark photons lead to an increase in the number of emitted neutrinos because of additional shell-burning episodes that delay core collapse. Furthermore, relatively strong couplings produce a thermonuclear runaway during O burning, which could result in a complete disruption of the star but requires more detailed simulations to determine the outcome. Our results show that pre-supernova neutrino signals are a potential probe of the dark photon parameter space.
La préparation de l’armée américaine à la transition énergétique
Authors: Lefeez Sophie 
Published: April 2021

Les armées américaines poursuivent depuis une quinzaine d’années une politique de transition énergétique en deux volets : production autonome d’énergies renouvelables, ou au minimum consommation d’énergies renouvelables, et conversion aux biocarburants. Leurs motivations sont principalement stratégiques et économiques. Initiée par le niveau fédéral, cette politique a été appropriée différemment par chacune des trois armées ( terre, air, mer ) en fonction de leur principal poste de dépense énergétique. L’armée de terre a ainsi encouragé la production d’énergies renouvelables sur ses emprises et la conversion d’une partie de sa flotte de véhicules terrestres à l’électrique. La Navy s’est résolument engagée sur la voie des biocarburants, sans réussir toutefois à faire décoller une industrie capable de répondre aux immenses besoins du Département à la défense à un prix concurrentiel. Quant à l’armée de l’air, ses efforts ne sont guère allés au-delà de la certification de ses aéronefs à l’usage des biocarburants. En 2015, les armées étaient capables de produire environ 82 % du total de l’énergie renouvelable consommée, mais seulement 3,6 % de la consommation totale d’électricité du Département à la défense. Elles se sont alors lancées dans des projets de plus grande capacité productive. L’arrivée au pouvoir des républicains a néanmoins mis un coup d’arrêt à certains programmes et modifié les priorités. Or, les armées voient dans les énergies renouvelables principalement un moyen de renforcer leur résilience et de gagner en autonomie stratégique : elles poursuivent donc leurs actions mais de manière plus discrète.
Living Lab de recherche et médiation scientifique : une tentative d’innovation populaire
Authors: Millet François , Ducoulombier Pauline 
Published: April 2021

De 2018 à 2021, l’association Relais d’sciences – Le Dôme a mené une démarche Living Lab dans le cadre du programme de recherche sur la transition énergétique et hydrogène Téthys. Cette démarche visait à produire avec la population des supports de médiation, puis des scénarios d’usages et des prototypes. En organisant des ateliers participatifs, Le Dôme a permis aux publics d’être reconnus dans une posture de participants. Cette exploration a permis d’expérimenter les modèles et structuration conceptuelle des Living Lab qui s’inscrivent dans la mise en place de «  projets portés par l’usager  » tels que l’acceptation de la diversité des parties prenantes, le cheminement du parcours d’innovation et le modèle Connaissance – Social – Affaire de signature de la mesure d’impact de tel projet. Il introduit également des réflexions sur les leviers de la participation motivant l’engagement dans de telles démarches et propose des pistes pour un changement de modèle d’action culturelle au sein des centres de culture scientifique en faveur d’une innovation populaire.
La transition énergétique normande mise à l’épreuve par des profanes-néophytes
Authors: Naudon Frédéric 
Published: April 2021

Un profane-néophyte peut-il, aux côtés d’un spécialiste, participer efficacement à la création de nouvelles connaissances ? Peut-il aider le « sachant » à mieux comprendre son propre domaine ? Cet article présente un dispositif expérimental original : proposer à des profanes-néophytes de mettre à l’épreuve un projet technologique intégré dans le chemin de transition écologique que s’est choisi une région, la Normandie. Questions techniques inédites, problématique sociale impensée et étonnements sur la conduite du projet, les profanes-néophytes iront jusqu’à favoriser l’émergence d’un autre chemin de transition énergétique et feront apparaître les difficultés, ou peut-être l’impossibilité, de réunir dans un même objet, deux projets différents : un bateau-école à hydrogène et un démonstrateur industriel. Les résultats de ce dispositif expérimental peuvent, nous l’espérons, alimenter la réflexion sur le rôle des profanes-néophytes dans des dispositifs participatifs de type mini-publics et poser la question de leur possible légitimité technique.
Oxycarenus breddini Bergroth, 1905 (Hemiptera: Heteroptera: Oxycarenidae): type material discovered, lectotype designated, and neotype set aside
Authors: Scudder Geoffrey G.E. 
Published: April 2021

Abstract
Type material (treated as syntypes) of Oxycarenus breddini Bergroth, 1905 has been found in the Institut Royal des Sciences Naturelles de Belgique in Brussels, Belgium. A lectotype has been designated, and so the neotype is redundant.
Maintainability of manpower system with restricted recruitment
Authors: Ossai EO 
Published: April 2021

The maintainability of a manpower system is studied under a Markov framework. The classical method of controlling only one factor of flow is extended to highlight the case in which two factors are under control simultaneously. One special case of this extension, where recruitment of units faces partial embargo, is given, which led to other important results.KEY WORDS: Manpower structure, Maintainability, Factors of flow, Markov model Probability.
Packets routing and bandwidth sensing in a network traffic: Ant colony optimization tactic.
Authors: Ogban Felix U. , Nentui Roy 
Published: April 2021

Packets routing and bandwidth sensing in a network platform remains an integral part of the study of signal flow.The algorithm to route packets in a network link called the AntNet algorithm was inspired by the behavior of real ant colonies. At each node in the network, a forward ant deposits some amount of pheromones at different links that responds to the node’s queue length. In this paper, we propose the inclusion of the computation of paths to adapt with the Depth Search Ant Explorer Network (DS-ANTENet) algorithm for discrete problems as an IP based mechanism. This method is tested and the efficiency is compared to the original AntNet algorithm and the Link-State algorithm to check the transmission of computing traffic flows between the nodes. We then made comparison with the algorithms proposed in the literature. The protocols were sorted out in terms of average number of lost packets ranging from the higher priority queue to the lower priority queue which then resulted to the fact that; First, AntNetBW (loss ratios reduction of 9.6% when compared to the AntNet and the Link-State algorithm respectively. Secondly, SANTENetBW (loss ratios reduction of 8.3% and 36.7% when compared to the AntNet and the Link-State algorithm respectively. Finally, DS-ANTENet (loss ratios reduction 0.7% and 33.2% when compared to the AntNet and the Link- State algorithm respectively.Keywords: Packets Routing, Bandwidth Sensing, Network Traffic, Ant Colony Optimization Algorithm, AntNet
Metal Sorption Capabilities of Two Common Plants in Tropical Wetlands - Bambusa vulgaris and Raffia bambusa
Authors: Ofori-Sarpong G. , Asamoah R. K. , Gordon J. J. K. , Amankwah R. K. 
Published: April 2021

In most developing countries, careless disposal of waste dry cell batteries and Ni-Cd batteries from mobile phones and rechargeable lamps has led to an increase in some metal contaminants including copper, lead, nickel and cadmium in soils and water bodies. These metals have the potential to cause serious, and sometimes, irreversible health effects if they are consumed. Unfortunately, in most cases, either the water bodies are not treated prior to consumption or the water treatment methods do not target the removal of these metals. This study therefore sought to mimic the bio-filtering effect of wetlands by assessing the capabilities of two common plants in tropical wetlands; Raffia bambusa and Bambusa vulgaris to remove Cu2+, Pb2+, Ni2+ and Cd2+ from wastewater. Spectroscopic characterisation indicated that some of the functional groups on the biomass were the OH, C=O and COOH, and R. bambusa appeared to have more pronounced groups than B. vulgaris. The results show maximum sorption of 95% Cu and Pb by biomass derived from roots of these plants. Sorption of Cd and Ni were lower at about 40%. By using a 3-stage sorption system of live plants, sorption of Cd and Ni increased up to 80%. Keywords: Heavy Metals, Sorption, Biomass, Bambusa vulgaris, Raffia bambusa
The Geometry and Structural Analysis of the Gold Deposits of Chirano Mine
Authors: Ackon-Wood K. , Kuma J. S. Y. , Yendaw J. A. 
Published: April 2021

The Chirano Mine gold deposit is a typical example of a structurally controlled deposit developed along the Kumasi Basin and the Sefwi Belt margin structure. The area has undergone various regimes of structural deformations. Consequently, all the Chirano deposits are intimately associated with shears and faults along a single continuous structural corridor known as the Chirano Shear Zone (CSZ). The CSZ geometry has been categorised into three major zones namely: (i) Laminated veins in shears, (ii) Breccia and (iii) Ductile to brittle ductile zones. The shear veins trend NE-SW and N-S, are laminated and occur in the sheared fabric close to the footwall. Penetrative foliated zones varying from a few centimeters to several meters constitute the ductile to brittle-ductile structures. Gold grades are much higher within this zone. Analysis of cataclasis intensity recorded in drill core confirms a semi brittle form of deformation within the mineralised domain. The CSZ has different orientations in dip and strike from the south of the mining lease to the north. The subtle changes in orientation are deposit dependent. The structure has a sinuous shape and tends to pinch and swell. The current geometry and the distribution of stratigraphy and orebodies at Chirano is a manifestation of the complex interplay of magmatic and hydrothermal events in the area. Keywords: Ductile, Brittle-Ductile, Breccia, Chirano Shear Zone, Chirano Lode Horizon