bluuebunny/crossref_metadata_2025_split huggingface dataset:
The VAO Transient Facility
Authors: Graham Matthew J. , Djorgovski S. G. , Drake Andrew , Mahabal Ashish , Williams Roy , Seaman Rob 
Published: April 2012

AbstractThe time-domain community wants robust and reliable tools to enable the production of, and subscription to, community-endorsed event notification packets (VOEvent). The Virtual Astronomical Observatory (VAO) Transient Facility (VTF) is being designed to be the premier brokering service for the community, both collecting and disseminating observations about time-critical astronomical transients but also supporting annotations and the application of intelligent machine-learning to those observations. Two types of activity associated with the facility can therefore be distinguished: core infrastructure, and user services. We review the prior art in both areas, and describe the planned capabilities of the VTF. In particular, we focus on scalability and quality-of-service issues required by the next generation of sky surveys such as LSST and SKA.
Searching for Fast Optical Transients using a Veritas Cherenkov Telescope
Authors: Griffin Sean C. 
Published: April 2012

AbstractAstronomical transients are intrinsically interesting objects to study. However, fast optical transients (μs time-scales) are a largely unexplored field of optical astronomy. Most optical observations use instruments that have integration times of the order of seconds and are thus unable to resolve fast transients. Current-generation atmospheric Cherenkov gamma-ray telescopes such as Veritas, which consists of four 12-m telescopes, have huge collecting areas, much larger than those of any existing optical telescopes. This paper outlines the benefits of using a Cherenkov telescope to detect optical transients, and the implementation of the Veritas Transient Detector (TRenDy), a dedicated multi-channel photometer based on field-programmable gate arrays which can be used on Veritas for such studies without interfering with gamma-ray observations.
La Silla-QUEST Variability Survey in the Southern Hemisphere
Authors: Hadjiyska Ellie , Rabinowitz David , Baltay Charles , Ellman Nancy , Nugent Peter , Zinn Robert , Horowitz Benjamin , McKinnon Ryan , Miller Lissa R. 
Published: April 2012

AbstractWe describe the La Silla-QUEST (LSQ) Variability Survey. LSQ is a dedicated wide-field synoptic survey in the Southern Hemisphere, focussing on the discovery and study of transients ranging from low redshift (z < 0.1) SN Ia, Tidal Disruption events, RR Lyræ variables, CVs, Quasars, TNOs and others. The survey utilizes the 1.0-m Schmidt Telescope of the European Southern Observatory at La Silla, Chile, with the large-area QUEST camera, a mosaic of 112 CCDs with field of view of 9.6 square degrees. The LSQ Survey was commissioned in 2009, and is now regularly covering ~1000 square deg per night with a repeat cadence of hours to days. The data are currently processed on a daily basis. We present here a first look at the photometric capabilities of LSQ and we discuss some of the most interesting recent transient detections.
Proposal for Multi-Messenger Observations of Radio Transients by Nasu and Ligo-Virgo
Authors: Hayama Kazuhiro , Niinuma Kotaro , Oyama Tomoaki 
Published: April 2012

AbstractThe gravitational waves radiated from explosions of compact objects are expected to be accompanied by other astronomical radiation such as radio flares, neutrinos and gamma-rays. In order to improve the detection of gravitational waves, mutual follow-up observations have been proposed between gravitational wave telescopes and other astronomical telescopes, known as “multi-messenger” observations. We propose multi-messenger observations using the LIGO, Virgo and Nasu Radio Telescopes.
Variability with Wise
Authors: Hoffman Douglas , Cutri Roc , Fowler John , Masci Frank 
Published: April 2012

AbstractWise mapped the entire sky in four bands during its approximately 7-month cryogenic mission. The number of exposures for each point on the sky increased with ecliptic latitude, and ranged from ~12 on the ecliptic to over 1000 at the ecliptic poles. The observing cadence is well suited to studying variable objects with periods between ~2 hours to ~2 days on the ecliptic, with the maximum period increasing up to several weeks near the ecliptic poles. We present the method used to identify several types of variables in the Wise Preliminary Release Database, and the mid-IR light curves of several objects. Many of these objects are new, and include RR Lyr, Algol, W UMa, Mira, BL Lac and YSO-type variables, as well as some unknown objects.
Fast Transient Detection as a Prototypical “Big Data” Problem
Authors: Jones Dayton L. , Wagstaff Kiri , Thompson David , D'Addario Larry , Navarro Robert , Mattmann Chris , Majid Walid , Rebbapragada Umaa , Lazio Joseph , Preston Robert 
Published: April 2012

AbstractThe detection of fast (< 1 second) transient signals requires a challenging balance between the need to examine vast quantities of high time-resolution data and the impracticality of storing all the data for later analysis. This is the epitome of a “big data” issue—far more data will be produced by next generation-astronomy facilities than can be analyzed, distributed, or archived using traditional methods. JPL is developing technologies to deal with “big data” problems from initial data generation through real-time data triage algorithms to large-scale data archiving and mining. Although most current work is focused on the needs of large radio arrays, the technologies involved are widely applicable in other areas.
A Refined QSO Selection Method Using Diagnostics
Authors: Kim Dae-Won , Protopapas Pavlos , Trichas Markos , Rowan-Robinson Michael , Khardon Roni , Alcock Charles , Byun Yong-Ik 
Published: April 2012

AbstractWe present 663 QSO candidates in the Large Magellanic Cloud (LMC) that were selected using multiple diagnostics. We started with a set of 2,566 QSO candidates selected using the methodology presented in our previous work based on time variability of the MACHO LMC light curves. We then obtained additional information for the candidates by cross-matching them with the Spitzer SAGE, the 2MASS, the Chandra, the XMM, and an LMC UBVI catalogues. Using that information, we specified diagnostic features based on mid-IR colours, photometric redshifts using SED template fitting, and X-ray luminosities, in order to discriminate more high-confidence QSO candidates in the absence of spectral information. We then trained a one-class Support Vector Machine model using those diagnostics features. We applied the trained model to the original candidates, and finally selected 663 high-confidence QSO candidates. We cross-matched those 663 QSO candidates with 152 newly-confirmed QSOs and 275 non-QSOs in the LMC fields, and found that the false positive rate was less than 1%.
Real-Time Classification of Transient Events in Synoptic Sky Surveys
Authors: Mahabal Ashish A. , Donalek C. , Djorgovski S. G. , Drake A. J. , Graham M. J. , Williams R. , Chen Y. , Moghaddam B. , Turmon M. 
Published: April 2012

AbstractAn automated rapid classification of the transient events detected in modern synoptic sky surveys is essential for their scientific utility and effective follow-up when resources are scarce. This problem will grow by orders of magnitude with the next generation of surveys. We are exploring a variety of novel automated classification techniques, mostly Bayesian, to respond to those challenges, using the ongoing CRTS sky survey as a testbed. We describe briefly some of the methods used.
LOFT: Large Observatory For X-Ray Timing
Authors: Mignani R. P. , Zane S. , Walton D. , Kennedy T. , Winter B. , Smith P. , Cole R. , Kataria D. , Smith A. 
Published: April 2012

AbstractHigh-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, black-hole masses and spins, and the equation of state of ultra-dense matter. LOFT, the Large Observatory for Xray Timing, is specifically designed to study the very rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars. A 10-m2-class instrument in combination with good spectral resolution (<260 eV @ 6 keV) is required to exploit the relevant diagnostics, and has the potential of revolutionising the study of collapsed objects in our Galaxy and of the brightest supermassive black holes in active galactic nuclei. LOFT will carry two main instruments: a Large Area Detector (LAD), to be built at MSSL/UCL in collaboration with the Leicester Space Research Centre, and a Wide Field Monitor (WFM). The ground-breaking characteristic of the LAD (it will work in the energy range 2–30 keV) is a mass per unit surface in the range ~10 kg/m2, giving an effective area of ~10 m2 (@10 keV) at a reasonable weight—an improvement by ~20 over all predecessors. This will allow timing measurements of unprecedented sensitivity, providing the capability to measure the mass and radius of neutron stars with ~5% accuracy, or to reveal blobs orbiting close to the marginally stable orbit in active galactic nuclei. We summarise the characteristics of the LOFT instruments and give an overview of its expected capabilities.
Photographic Archives of Ukrainian Observatories: Digitizing a Heritage
Authors: Pakuliak Ludmila , Kazantseva Lilia , Virun Natalia , Andruk Vitaly 
Published: April 2012

AbstractWe describe a key project of the Ukrainian Virtual Observatory (UkrVO), namely, a collaboration to digitize the large collections of photographic plates that had been exposed during more than 100 years at Ukrainian observatories, and to combine the digitized images with CCD archives to form the UkrVO Joint Digital Archive. The application of flatbed scanners for digitizing plates is discussed.
Towards a More General Method for Filling Gaps in Time Series
Authors: Pascual-Granado J. , Garrido R. , Gutirrez-Soto J. , Martín-Ruiz S. 
Published: April 2012

AbstractThe need for a proper interpolation method for data coming from space missions like CoRoT is emphasized. A new gap-filling method is introduced which is based on auto-regressive moving average interpolation (ARMA) models. The method is tested on light curves from stars observed by the CoRoT satellite, filling the gaps caused by the South Atlantic Anomaly.
The International Liquid Mirror Telescope (ILMT) as a Variability Time Machine
Authors: Poels Joël , Borra Ermanno , Hickson Paul , Sagar Ram , Bartczak Przemyslaw , Delchambre Ludovic , Finet François , Habraken Serge , Swings Jean-Pierre , Surdej Jean 
Published: April 2012

AbstractDuring the year 2012 the International Liquid Mirror Telescope (a collaboration between astronomical institutions in Belgium, Canada, India and Poland) wil see first light. The instrument will provide substantial, in-depth sky coverage and make an unprecedented number of nightly observations.
A Global Robotic Telescope Network for Time-Domain Science
Authors: Street R. A. , Lister T. A. , Tsapras Y. , Shporer A. , Bianco F. B. , Fulton B. J. , Howell D. A. , Dilday B. , Graham M. , Sand D. , Parent J. , Brown T. , Horne K. , Dominik M. , Browne P. , Snodgrass C. , Kains N. , Bramich D. , Law N. , Steele I. 
Published: April 2012

AbstractLas Cumbres Observatory Global Telescope Network (LCOGT) is currently building a new kind of general-purpose astronomical facility: a fully robotic network of telescopes of 2m, 1m and 0.4m apertures and homogeneous instrumentation. A pan-network approach to scheduling (rather than per individual telescope) offers redundancy in the event of poor weather or technical failure, as well as the ability to observe a target around the clock. Here we describe the network design and instrumentation under development, together with the main science programmes already being lead by LCOGT staff.
FRATs: Searching for Fast Radio Transients in Real Time with LOFAR
Authors: ter Veen S. , Schellart P. , Falcke H. 
Published: April 2012

AbstractThe aim of the FRATs project is to detect single dispersed pulses from Fast Radio Transients with LOFAR in real time. The pulses can originate from pulsars, RRATS and other classes of known or unknown objects. To detect the pulses a trigger algorithm is run on an incoherent beam from the different LOFAR stations. The beam has a wide field of view and can be formed parallel to other observations. A precise localisation is achieved by storing and processing off-line the data from each dipole, giving all-sky coverage with a spatial resolution of the order of arc-seconds. The source is identified by making high-time-resolution images. The method has been tested by detecting and identifying a giant pulse from the Crab pulsar.
Period Analyses of 100+ Years of RR Lyræ Data
Authors: Walker E. N. 
Published: April 2012

AbstractThe GEOS data base for RR Lyr stars has been analysed to search for secondary (Blazhko) periods in several stars for which over 100 years of measurements are available. The results indicate that, even when there is a secondary period present, its behaviour can be dramatically different from star to star or even over time in the same star. In one star there is a clear correlation between the O–C diagrams for both the pulsation and Blazko periods; that has implications for the origins of the Blazhko periods.
Physical processes controlling ice concentrations in cold cirrus near the tropical tropopause
Authors: Jensen E. J. , Pfister L. , Bui T. P. 
Published: April 2012

Previous ice nucleation calculations have suggested that in the presence of wave‐driven temperature perturbations typical of the tropical tropopause layer (TTL), homogeneous freezing should produce ice concentrations well in excess of measured values. A statistical ice cloud parameterization that includes effects of sedimentation was recently used to show that if the wave amplitudes are not too large, a quasi steady state may be established wherein loss of ice crystals by sedimentation is balanced by nucleation of new ice crystals, and the resulting cloud ice concentrations agree well with observations. Here, we use numerical models to further evaluate the evolution of ice concentrations in TTL cirrus, including a range of cloud physical processes (homogeneous and heterogeneous ice nucleation, sedimentation, and radiatively driven dynamics). We use a one‐dimensional microphysical model with bin microphysics to show that as a result of gravitational size sorting, the mean ice concentrations over the life cycle of the clouds are considerably smaller than the peak ice concentrations produced by ice nucleation events. However, the mean ice concentrations predicted here are considerably higher than either those reported based on the statistical model or those indicated by the observations. With the baseline wave amplitudes, ice crystals nucleated heterogeneously do not quench rising supersaturation in cooling air parcels and prevent homogeneous nucleation that produces high ice concentrations. We also use a three‐dimensional cloud resolving model to show that radiatively driven internal circulations and entrainment do slowly shift the ice concentrations toward lower values, but the time required to dilute ice concentrations produced by homogeneous freezing to values comparable to measured ice concentrations is of the order of 12–24 h, which may be longer than typical TTL cirrus lifetimes.
Local sea surface temperatures add to extreme precipitation in northeast Australia during La Niña
Authors: Evans Jason P. , Boyer‐Souchet Irène 
Published: April 2012

This study examines the role played by high sea surface temperatures around northern Australia, in producing the extreme precipitation which occurred during the strong La Niña in December 2010. These extreme rains produced floods that impacted almost 1,300,000 km2, caused billions of dollars in damage, led to the evacuation of thousands of people and resulted in 35 deaths. Through the use of regional climate model simulations the contribution of the observed high sea surface temperatures to the rainfall is quantified. Results indicate that the large‐scale atmospheric circulation changes associated with the La Niña event, while associated with above average rainfall in northeast Australia, were insufficient to produce the extreme rainfall and subsequent flooding observed. The presence of high sea surface temperatures around northern Australia added ∼25% of the rainfall total.
Regulation of angiotensin II receptors beyond the classical pathway
Authors: Horiuchi Masatsugu , Iwanami Jun , Mogi Masaki 
Published: April 2012

The RAS (renin–angiotensin system) plays a role not only in the cardiovascular system, including blood pressure regulation, but also in the central nervous system. AngII (angiotensin II) binds two major receptors: the AT1 receptor (AngII type 1 receptor) and AT2 receptor (AngII type 2 receptor). It has been recognized that AT2 receptor activation not only opposes AT1 receptor actions, but also has unique effects beyond inhibitory cross-talk with AT1 receptor signalling. Novel pathways beyond the classical actions of RAS, the ACE (angiotensin-converting enzyme)/AngII/AT1 receptor axis, have been highlighted: the ACE2/Ang-(1–7) [angiotensin-(1–7)]/Mas receptor axis as a new opposing axis against the ACE/AngII/AT1 receptor axis, novel AngII-receptor-interacting proteins and various AngII-receptor-activation mechanisms including dimer formation. ATRAP (AT1-receptor-associated protein) and ATIP (AT2-receptor-interacting protein) are well-characterized AngII-receptor-associated proteins. These proteins could regulate the functions of AngII receptors and thereby influence various pathophysiological states. Moreover, the possible cross-talk between PPAR (peroxisome-proliferator-activated receptor)-γ and AngII receptor subtypes is an intriguing issue to be addressed in order to understand the roles of RAS in the metabolic syndrome, and interestingly some ARBs (AT1-receptor blockers) have been reported to have an AT1-receptor-blocking action with a partial PPAR-γ agonistic effect. These emerging concepts concerning the regulation of AngII receptors are discussed in the present review.
Absolute atomic chlorine densities in a Cl2 inductively coupled plasma determined by two-photon laser-induced fluorescence with a new calibration method
Authors: Booth J P , Azamoum Y , Sirse N , Chabert P 
Published: April 2012

Abstract
Absolute densities of chlorine atoms were determined in an inductively coupled plasma in pure chlorine gas as a function of gas pressure and RF power by two-photon laser-induced fluorescence. A new technique is proposed to put the relative two-photon laser-induced fluorescence (TALIF) measurements on an absolute scale, based on photolysis of Cl2 gas (without plasma) with a tripled Nd : YAG laser at 355 nm. Because the dissociation cross-section and photo-dissociation laser beam energy density are well known, the absolute densities can be determined with high accuracy. We find that the ratio of the Cl atom density normalized to the Cl2 gas density without plasma

at the reactor centre increases with RF power and decreases with gas pressure, reaching 20% at 2 mTorr 500 WRF.
Equivalent plastic strain gradient enhancement of single crystal plasticity: theory and numerics
Authors: Wulfinghoff Stephan , Böhlke Thomas 
Published: April 2012

We propose a visco-plastic strain gradient plasticity theory for single crystals. The gradient enhancement is based on an equivalent plastic strain measure. Two physically equivalent variational settings for the problem are discussed: a direct formulation and an alternative version with an additional micromorphic-like field variable, which is coupled to the equivalent plastic strain by a Lagrange multiplier. The alternative formulation implies a significant reduction of nodal degrees of freedom. The local algorithm and element stiffness matrices of the finite-element discretization are discussed. Numerical examples illustrate the advantages of the alternative formulation in three-dimensional simulations of oligo-crystals. By means of the suggested formulation, complex boundary value problems of the proposed plastic strain gradient theory can be solved numerically very efficiently.
Effects of borrowers' quality on the size of market response to bank loan announcements in China
Authors: Zhang Yuan , Gan Christopher , Li Zhaohua 
Published: April 2012

PurposeThe purpose of this paper is to examine the effects of borrowers' quality on the size of market reaction to bank loan announcements in the Chinese financial market, where poor quality borrowers are prevalent and the banking system is highly controlled by the Chinese government.Design/methodology/approachThe paper uses different measures to proxy for borrower quality, including the borrowers' information opaqueness, possibility of expropriation and their financial status. A cross‐sectional regression analysis was conducted to investigate the relationship between the market response to bank loan announcements and the borrowers' quality.FindingsIt is revealed that the negative market response to bank loan announcements is particularly significant for borrowing firms with lower quality, including firms that are opaque, have a higher possibility of expropriation or tunnelling, have ineffective expropriation‐reduction mechanisms, are controlled by the state and are in financial distress, for the sample period 1996 to 2009. Furthermore, to test whether there is any significant difference on the effects of the borrowers' quality on the size of the market response to bank loan announcements following China's announcement of share‐split reform in 2005, this paper splits the sample period into sub samples, 1996 to 2004 and 2004 to 2005. The results on the effects of the borrowers' quality on the size of market response to bank loan announcements for the sub sample period 1996 to 2004 are similar to those for the full sample 1996 to 2009.Research limitations/implicationsThe paper's findings imply that the reforms in the Chinese financial market since 2005 do not have any significant effects on the borrowers' quality on the size of the market response to bank loan announcements for the full sample period.Originality/valueThis paper differs from previous studies in regards to the sample period and the measurements of the possibility of expropriation or tunnelling. The paper contributes to the banking and corporate governance literature.