bluuebunny/crossref_metadata_2025_split huggingface dataset:
X-ray Binary Transients in the Magellanic Clouds and the Milky Way
Authors: Charles P. , Anderson G. , Coppejans D. , Motsoaledi M. 
Published: August 2019

AbstractThe X-ray sky is dominated by luminous galactic sources, variable on time-scales from milliseconds to years. Their eruptive behaviour is now under continuous monitoring by MAXI, Swift, INTEGRAL and other high-energy missions, and representing a superb exemplar of time-domain astronomy. Understanding the astrophysics of such variability requires multi-wavelength follow-up studies from a suite of ground- and space-based facilities. As SALT is a 100% Q-scheduled telescope, one of its key scientific capabilities is related to Target-of-Opportunity (ToO) programmes, and there has been a dedicated SALT Large Programme on Transients in place since 2016, a significant fraction of which has been devoted to the follow-up of X-ray binary transients. This Workshop addressed questions of how such programmes should evolve once the era of MeerKAT and MeerLICHT begins in ∼2018-9 (as well as other huge surveys at optical wavelengths), identifying the range of facilities that would be needed, and the key science topics. There is a clear and growing need for responses to transients to be faster (within minutes if possible), and to be multi-wavelength (particularly in radio and X-ray). Furthermore, extended ongoing coverage of such events (days to weeks for the next ‘V404 Cyg’-type outburst) will be needed for maximum astrophysical return. That would require careful management and coordination of a wide range of ground- and space-based facilities, and optimising coverage against logistical constraints that are often conflicting.
Machine Learning for Transient Classification
Authors: Lochner M. , Bassett B. 
Published: August 2019

AbstractWe organized Workshop 13, Machine learning for transient classification, into two distinct question-and-answer parts. The first was a so-called ‘idiot session’, in which basic questions about machine learning and artificial intelligence were elicited from the audience. The second focussed discussions on the application of artificial intelligence to transient astronomy.The workshop proved highly successful. The room was packed, and the many interesting questions and discussions were good preparation for the presentation to be made on ‘machine learning’ during the plenary session the following day.The workshop clearly reflected the general awareness and excitement in the community for the potential of machine learning in regard to transient detections in astronomy in the era of ZTF, LSST, LIGO and the SKA. Several of the presentations at this Symposium had already been exhibiting specific attention to the roles of machine-learning techniques and products. The extent to which the younger generations were being involved was clearly noticeable, and that augured well for research into workable solutions for astronomy’s ‘Big Data’ problems which – as stated frequently at this conference – are only just around the corner.
Calibration and Standardisation
Authors: Sterken C. 
Published: August 2019

AbstractOne of the great challenges in time-domain astronomy is the problem of combining data obtained at various epochs with very different instruments. These problems are mostly discussed from within a specific observational mode, for example photometry, spectroscopy or imaging. This Workshop explored by example diverse pitfalls of time-domain calibration by discussing calibration and standardisation problems across various types of variables.
Symbiotic Stars in the Local Group of Galaxies: POINT-AGAPE Catalogue Revisited
Authors: Drozd K. , Mikołajewska J. , Darnley M. , Iłkiewicz K. , Caldwell N. , Shara M. 
Published: August 2019

AbstractThis research was prompted by the discovery of 35 new or candidate symbiotic stars during a targeted search in the Local Group of Galaxies. A catalogue of a further 200 or so such objects has now been compiled. Many of them could be identified with counterparts in the POINT-AGAPE Catalogue. However, information in the Catalogue is limited to position, brightness and possible period, and light-curves are not available. The poster presented an example of a light-curve of a symbiotic star retrieved from original Point-Agape Catalogue data.
Kepler-410Ab and Transit Timing Variations
Authors: Gajdoš P. , Parimucha Š. , Fedurco M. 
Published: August 2019

AbstractOur poster presented a new analysis of the transit-time variations displayed by the extrasolar planet Kepler-410Ab. We assumed that the observed changes in the transit times are caused by the gravitational influence of another body in the system. To determine the mass of that perturbing body, we considered the light-time effect and an analytical approximation of the perturbation model. The solutions resulting from both methods gave comparable results, with an orbital period of 970 days and a slightly eccentric orbit for the third body. We proposed two possible models of a perturbing body orbiting a common barycentre with Kepler-410A: a single star with mass of at least 0.906 M⊙, or a binary star with a total component mass of at least 2.15 M⊙.
Statistical research into correlation 2 between solar filaments and flare activities
Authors: Lin G. 
Published: August 2019

AbstractThere is a strong correlation between coronal mass ejection transients and chromospheric H-α activity. Solar physicists hope to ascertain what causes coronal disturbances, and in our current investigation we are trying to address that problem by assessing the likelihood that a coronal disturbance is associated with other manifestations of the same abrupt, perturbing event such as a flare. The correlation, if any, between filament and flare can be derived by a method of image processing. Our next approach is to give the results of statistical research by studying a century of chromospheric Hα observations. This poster describes the concept and preliminary experiences of deriving the characteristics of a filament and a flare.
A CoRoT View of the ζ Aur binary HR 6902
Authors: Maceroni C. , Montalbán J. , Da Silva R. , Semaan T. , Mosser B. , Rainer M. , Poretti E. , Griffin E. 
Published: August 2019

AbstractHR 6902 was the first target of a systematic study by Griffin (1986, JApA, 7, 195) of binaries showing composite spectra. It is also a well-studied member of the ζ Aur class. ζ Aur systems are long-period eclipsing binaries that are comprised of an evolved giant primary and a hot dwarf companion. Although those component stars have very different effective temperatures they have similar luminosities in the blue and near-UV regions, and hence display a composite spectrum at those wavelengths. In principle the ζ Aur systems are excellent tests of evolutionary and structural stellar models. In recent years the somewhat fragmentary eclipse photometry of HR 6902 has been out-classed by the high-precision continuous monitoring by the space mission CoRoT. HR 6902 was selected as a primary target of its seismology field, because the possible detection of solar-like pulsations in a giant component of a double-lined eclipsing binary could help to calibrate the scaling relation of giant pulsators. Our poster reported the results of a new analysis based on the CoRoT observations and follow-up spectroscopy with HARPS at the ESO 3.6-m telescope at La Silla.The unprecedented accuracy of the CoRoT photometry enabled us to:
improve drastically the accuracy of the binary orbit and stellar parameters (by a factor ~10 for the radii)extend the test of validity/calibration of the scaling relations to high stellar mass and radius, and put constraints on the evolutionary state (particularly since this binary is certainly free from tidal effects).
Searching for Long-Period Binary Central Stars of Planetary Nebulae with SALT HRS
Authors: Miszalski B. , Manick R. , Mikołajewska J. , Iłkiewicz K. , Kamath D. , Van Winckel Hans 
Published: August 2019

AbstractIn the last decade great strides have been made in understanding the role of binary stars in the evolution and shaping of planetary nebulæ (PNe). Observational efforts have mainly focused on finding close binaries with orbital periods of 1 day or less. Those close binary systems make up around 1 in 5 PNe, and constitute the youngest accessible window into the aftermath of the critical and unobserved common-envelope (CE) phase of binary-star evolution. The poster focused on our recent work with the High Resolution Spectrograph (HRS) on the Southern African Large Telescope (SALT) to search for long-period binaries in PNe. Considerably less is known about such long-period binaries with orbital periods of weeks to years, but they may be fundamental to improving CE population synthesis models and for determining the total binary fraction of PNe. The queue-mode operation of SALT and the excellent sensitivity and stability of HRS (which is enclosed in a vacuum tank) are ideally suited to detecting binaries with low radial-velocity amplitudes over the expected timescales of weeks to years. Many exciting new discoveries about binaries have already been made in this newly-accessible southern horizon in time-domain astronomy thanks to the many unique advantages of SALT.
Companion(s) of the Eclipsing Binary KIC 3832716
Authors: Parimucha Š. , Fedurco M. , Gajdoš P. 
Published: August 2019

AbstractDetailed analyses of observations by the Kepler satellite may reveal unknown facts about objects that were previously regarded as eclipsing binaries. We present results of our analysis of such an object, KIC 3832716. We show that the system actually contains two eclipsing binaries (EB1 and EB2), with orbital periods of 1.14 and 2.17 days, orbiting around their common centre of mass with period of at least 1400 days and with an estimated mass ratio of 0.7 ± 0.3. Analyses of the (O–C) diagrams of both eclipsing pairs show three different types of variation: (i) long-term changes probably due to light-time effects, (ii) spikes caused by the superposition of the eclipses of both binaries, and (iii) semi-regular variations in EB1 with a period of 57 days, presumably caused by the presence of spots on its secondary component.
Detecting AGB stars in LG Dwarf Galaxies for Understanding Galaxy Formation and Evolution
Authors: Saremi E. , Javadi A. , van Loon J. , Khosroshahi H. , Torki M. 
Published: August 2019

AbstractStars are the main ingredients of galaxies, and the sites of the creation of most chemical elements in our universe. The knowledge that we gain from studying nearby resolved stellar populations assists directly our ability to measure the properties of distant galaxies. The overall objective of this project is to study galaxy formation and evolution in a complete environment of the dwarf galaxies in the Local Group, by using the same methods for all of them. For that purpose, we used the INT to conduct a monitoring survey of the majority of Local-Group dwarf galaxies in order to identify the most evolved AGB stars that are long-period variables (LPV). LPV stars reach their maximum brightness amplitudes at optical wavelengths, owing to changes in temperature. They trace stellar populations as young as ∼30 Myr up to as old as ∼10 Gyr, and identifying them is one of the best ways of reconstructing star-formation history using a method that we have developed and applied successfully to other Local-Group galaxies. Since the luminosity variations span 100–1000 days, we planned observations over 10 epochs, spaced ∼3 months apart; 9 epochs of data have so far been obtained.
Accurate Photometry with Digitized Photographic Plates of the Moscow Collection
Authors: Sokolovsky K. V. , Zubareva A. M. , Kolesnikova D. M. , Samus N. N. , Antipin S. V. , Belinski A. A. 
Published: August 2019

AbstractPhotographic plate archives contain a wealth of information about the positions and brightness of celestial objects decades ago. Plate digitization is necessary to make this information accessible, but extracting it is a technical challenge. We have developed algorithms to extract photometry with an accuracy of better than ∼0.1 mag. in the range 13 < B < 17 mag from photographic images obtained in 1948–1996 with the 40-cm Sternberg Institute astrograph (30 × 30 cm plate size, 10 × 10 deg field of view) and digitized using a flatbed scanner. The extracted photographic light-curves are used to identify thousands of new high-amplitude variable stars (>0.2 mag). The algorithms are implemented in the free software VaST available at http://scan.sai.msu.ru/vast/
One-dimensional beam-steering Fabry–Perot cavity (FPC) antenna with a reconfigurable superstrate
Authors: Ji Lu-Yang , Fu Shuai , Zhang Lin-Xi , Li Jian-Ying 
Published: August 2019

AbstractIn this work, a new reconfigurable discrete 1D beam-steering Fabry–Perot cavity antenna with enhanced radiation performance is presented. It consists of a probe-fed patch antenna printed on the ground plane and a reconfigurable metasurface acting as the upper partially reflective surface to realize beam steering. By utilizing 6 × 6 proposed reconfigurable unit cells on the superstrate, the beam-steering angle can be effectively enhanced from ±7° to ±17° with fewer active elements and a much simpler biasing network. The proposed antenna was fabricated to validate the feasibility. Good agreement between the simulated and measured results is achieved. Moreover, the measured realized gains are over 11 dBi with a gain variation from the boresight direction to the tilted direction <0.2 dBi.
Evaluation of herbicides for hair fescue (Festuca filiformis) management and potential seedbank reduction in lowbush blueberry
Authors: White Scott N. 
Published: August 2019

AbstractHair fescue is a widespread, seed-limited perennial grass in lowbush blueberry fields. Growers rely on pronamide, an expensive and difficult herbicide to use, for hair fescue management. Recent herbicide registrations provide opportunity to reduce pronamide use, though effects of these herbicides on hair fescue suppression and seedbank reduction are not well understood. The objectives of this research were to determine (1) the effects of herbicides currently registered in lowbush blueberry on suppression of hair fescue tufts and (2) whether suppression of hair fescue with these herbicides reduces hair fescue seedbanks. Pronamide gave the most consistent reductions in flowering tuft density, though applications after both autumn pruning and autumn of the nonbearing year were required to reduce the hair fescue seedbank by >60% across sites. Nonbearing-year hexazinone applications did not control hair fescue or reduce the seedbank. Nonbearing-year terbacil applications reduced flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. Glufosinate applications following autumn pruning or in the spring of the nonbearing year did not suppress hair fescue or reduce the seedbank. Spring nonbearing-year foramsulfuron applications, alone or after autumn or spring glufosinate applications, reduced hair fescue flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. In contrast, autumn and spring glufosinate applications followed by spring nonbearing-year foramsulfuron applications, when combined with autumn nonbearing-year pronamide applications, reduced flowering tuft density in both the nonbearing and bearing years and reduced the hair fescue seedbank by 58% to 83% across sites. Results indicate that hair fescue seedbanks can be reduced in lowbush blueberry fields and that a reduction in pronamide use will require alternative bearing-year treatments to prevent tuft recovery and seed production.
Inducing Unconscious Stress
Authors: van der Ploeg Melanie M. , Brosschot Jos F. , Quirin Markus , Lane Richard D. , Verkuil Bart 
Published: August 2019

Abstract. Stress-related stimuli may be presented outside of awareness and may ultimately influence health by causing repetitive increases in physiological parameters, such as blood pressure (BP). In this study, we aimed to corroborate previous studies that demonstrated BP effects of subliminally presented stress-related stimuli. This would add evidence to the hypothesis that unconscious manifestations of stress can affect somatic health. Additionally, we suggest that these findings may be extended by measuring affective changes relating to these physiological changes, using measures for self-reported and implicit positive and negative affectivity. Using a repeated measures between-subject design, we presented either the prime word “angry” ( n = 26) or “relax” ( n = 28) subliminally (17 ms) for 100 trials to a student sample and measured systolic and diastolic BP, heart rate (HR), and affect. The “angry” prime, compared to the “relax” prime, did not affect any of the outcome variables. During the priming task, a higher level of implicit negative affect (INA) was associated with a lower systolic BP and diastolic BP. No association was found with HR. Self-reported affect and implicit positive affect were not related to the cardiovascular (CV) activity. In sum, anger and relax primes elicited similar CV activity patterns, but implicit measures of affect may provide a new method to examine the relationship between (unconscious) stress and health.
Distinguishing TBI Malingering and Fatigue Using Event-Related Potentials
Authors: Robinson Lindsey K. , McFadden Sandra L. 
Published: August 2019

Abstract. Poorer-than-expected performance on cognitive-behavioral tasks may indicate malingering, or it could be an outcome of fatigue, resulting in false positives when suboptimal task performance is used to flag individuals feigning or exaggerating symptoms of traumatic brain injury (TBI). The primary goal of this study was to examine the P3 event-related potentials (ERP) and behavioral outcomes associated with TBI malingering and fatigue, in order to distinguish between them. A secondary goal was to determine if history of TBI (hTBI) is associated with differences in fatigue, ERPs, or performance on a short-term memory task. Participants completed the Mental Fatigue and Related Symptoms (SR-MF) questionnaire and were interviewed to assess TBI history, then they completed a computerized “old/new” (match-mismatch) task while ERPs were recorded, under three conditions: Normal, Malinger, and Fatigue. Participants reported mild fatigue at the end of study, with no difference between individuals reporting a history of TBI ( n = 32) and healthy controls ( n = 47). Fatigue was associated with prolonged P3 latency but was otherwise indistinguishable from Normal. In contrast, Malinger was clearly distinguished from Normal by significantly lower accuracy, longer reaction times, reduced P3 amplitude on Match trials, and a smaller old/new ERP effect. Individuals with a history of TBI reported clinical levels of fatigue at baseline but did not differ significantly from healthy controls on any behavioral or ERP measure. The results support the use of behavioral and ERP measures to identify malingering, without concern over confounding effects of mild subjective fatigue, including mild fatigue induced by testing.
Mantle Dynamics of the Eastern Mediterranean and Middle East: Constraints From P‐Wave Anisotropic Tomography
Authors: Wei Wei , Zhao Dapeng , Wei Feixiang , Bai Xiang , Xu Jiandong 
Published: August 2019

AbstractHigh‐resolution images of P‐wave anisotropic tomography beneath the Eastern Mediterranean and Middle East are determined by inverting a large number of high‐quality P‐wave arrival times. Our results clearly show along‐strike variations of subducting slabs in the Hellenic subduction zone. At least three high‐velocity anomalies are imaged beneath and behind the north Hellenides, which are associated with the subducting Hellenic slab at different stages, while in regions further south, a single slab is revealed that has subducted down to a depth of ~1,100 km. The slab feature is not prominent in the Cyprus subduction zone, but a fine‐scale high‐velocity structure is revealed beneath the central Anatolia, which may reflect the detached Cyprus slab. Trench‐parallel fast‐velocity directions occur in the forearc mantle wedge of the Hellenic subduction zone, which may reflect mantle flow induced by slab curvature. In the backarc north Aegean and westernmost Anatolia, dominant NNE‐SSW to N‐S fast‐velocity directions exist in the shallow mantle, which accord well with the extensional direction of present deformation at the surface, suggesting a vertically coherent deformation in the lithosphere. Our results reveal a large‐scale mantle flow beneath western Arabia, which is possibly related to the Zagros and Caucasus orogens and westward motion of the Anatolia lithosphere. The Arabian lithospheric plate is thinner beneath the Zagros than that under the Mesopotamian Foredeep, suggesting that a large portion of the crust was scrapped off from the subducted Arabian lithosphere during the Zagros orogen.
A Time‐Dependent Model of Elastic Stress in the Central Apennines, Italy
Authors: Caporali A. , Zurutuza J. , Bertocco M. 
Published: August 2019

AbstractSeismicity in the Central Apennines is characterized by normal faulting with dip NE‐SW near 45°. If the stress at the hypocenter of the 2016 Norcia (Mw= 6.5) and 2009 L'Aquila (Mw= 6.3 on the Paganica fault) earthquakes originated only from stress transfer from previous historical events, the orientation of the principal stress axes would have been inconsistent with the observed tensional regime. The additional contribution of a regional stress is thus required, but Global Navigation Satellite System geodesy provides only stress rates. We empirically estimate a time multiplier for the regional stress rate, computed with a dense Global Navigation Satellite System network, such that the principal stress axes resulting from the sum of the stress transferred by previous events and the regional stress rate multiplied by the empirical temporal scale are consistent with normal faulting, both at the L'Aquila and Norcia hypocenters. Based on a Catalogue of 36 events of magnitude larger than 5.6, we estimate the total Coulomb stress at depths and along planes parallel to those of L'Aquila and Norcia. We provide evidence of an asymmetry of the Coulomb stress leading to a stress concentration near the hypocenter of the two events just prior of the 2009 and 2016 earthquakes. This stress anomaly disappeared after the two events. Similar stress patterns are observed for earlier events, which took place in 1461 at L'Aquila, 1703 on the Montereale plain, and in 1703 at Norcia/Valnerina. The 1997 sequence of Colfiorito exhibits a similar, anisotropic Coulomb stress pattern. Other areas with a similar stress anisotropy could be seismic gaps.
Tidal Distortions Related to Extreme Atmospheric Forcing Over the Inner Shelf
Authors: Paniagua‐Arroyave Juan F. , Valle‐Levinson Arnoldo , Parra Sabrina M. , Adams Peter N. 
Published: August 2019

AbstractInner shelf transport is driven by the combination of tides, waves, density gradients, and wind that interact with bottom bedforms. To extend understanding of shoal‐swale bathymetry influences on inner‐shelf hydrodynamics, we provide observations at a swale ~13 m deep within Cape Canaveral shoals, ~36 km away from Hurricane Matthew's path during October 2016. Observations document a unidirectional flow that reached 2.7 m/s at a distance ~15 km away from the shoreline. The flow changed direction, over the course of the storm, counterclockwise from southwestward (~2.7 m/s) to northeastward (~1 m/s). The unidirectional flow modified tides over the inner shelf analogously to a river discharge in a channelized tidal flow, producing overtides of the semidiurnal tidal harmonic. Our results provide measurements during extreme conditions related to shore parallel‐propagating hurricanes that can inform morphodynamic and ecological models.