bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of the embryo quality on the risk of multiple pregnancies
Authors: Braga Daniela Paes de Almeida Ferreira , Setti Amanda S. , Figueira Rita de Cássia S. , Iaconelli Assumpto , Borges Edson 
Published: July 2014

SummaryThe aim of the present study was to determine the chance of pregnancy and the risk of multiple pregnancies taking into account the number and quality of transferred embryos in patients >36 years old or ≤36 years old. For this study, 1497 patients undergoing intra-cytoplasmic sperm injection (ICSI) cycles in a private assisted reproduction centre were split into groups according to the number and quality of the transferred embryos on the third or fifth day of development. The pregnancy rate and multiple pregnancy rate were compared between the embryo quality groups in patients <36 years old or ≥36 years old. In patients <36 years old, for the day 3 embryo transfer, no significant difference was noted in the pregnancy rate when the groups were compared. However the multiple pregnancy rate was increased by the transfer of an extra low-quality embryo (17.1 versus 28.2%, P = 0.020). For day 5 embryo transfer, the transfer of an extra blastocyst significantly increased the pregnancy rate (36.0 versus 42.4%, P < 0.001) and the multiple pregnancy rate (4.4 versus 16.9%, P < 0.001). In older patients, no significant difference was noted in the pregnancy rate when the groups were compared. However, when an extra low-quality embryo was transferred, a significantly increased rate of multiple pregnancies was observed for day 3 (18.2 versus 26.4%, P = 0.049) and day 5 embryo transfers (5.2 versus 16.1%, P < 0.001). In conclusion, the transfer of an extra low-quality embryo may increase the risk of a multiple pregnancy. In younger patients, the transfer of an extra low-quality blastocyst may also increase the chance of pregnancy.
DOUGLAS–RACHFORD FEASIBILITY METHODS FOR MATRIX COMPLETION PROBLEMS
Authors: ARAGÓN ARTACHO FRANCISCO J. , BORWEIN JONATHAN M. , TAM MATTHEW K. 
Published: July 2014

AbstractIn this paper, we give general recommendations for successful application of the Douglas–Rachford reflection method to convex and nonconvex real matrix completion problems. These guidelines are demonstrated by various illustrative examples.
WHITE TIME
Authors: Mills Charles W. 
Published: July 2014

AbstractThe racialization of space is the subject of a huge body of literature, most recently in George Lipsitz’s (2011)How Racism Takes Place. But less has been done on the ways in which time could be racialized. Inspired by provocative treatments of the subject in writings by Michael Hanchard (1999) and Lawrie Balfour (2011), I suggest in this paper that we need to explore the workings of a “White temporal imaginary” analogous to Lipsitz’s “White spatial imaginary,” which likewise serves to protect White racial privilege from the threatening encroachments of racial justice. Using Eviatar Zerubavel’s (2003)Time Mapsas a jumping-off point, I argue accordingly for the recognition of a “White time,” a “sociomental” representation of temporality shaped by the interests and experience of the White “mnemonic community.” The concept is obviously one of potentially very general usefulness, but in this essay I seek to apply it specifically to the dominant discourse on justice in political philosophy, as framed for the past forty years by John Rawls’ ([1971] 1999c) “ideal theory.” The relevance to the postracial theme of this issue is that, because of the peculiarity of philosophy as a discipline, it can claim it was always, or always-already, postracial, dealing as it ostensibly does with the (timeless) human condition as such. By making ideal theory—the normative theory of a perfectly just society—central to the conceptualization of social justice, by never exploring how radically different actual societies are from the ideal of society as “a cooperative venture for mutual advantage,” an exclusionary sociohistorical framework is established that makes the Euro-time of the West—abstracted out of the West’s relations of domination over people of color—the Greenwich Mean Time of normativity, while the alternative non-White temporality of structurally unjust societies requiring rectificatory racial justice remains a subject permanently untimely.
Markarian survey and Markarian galaxies
Authors: Mickaelian Areg M. 
Published: July 2014

AbstractMarkarian survey (or the First Byurakan Survey, FBS) was the first systematic survey for active galaxies and was a new method for search for such objects. Until now, it is the largest objective prism survey of the sky (17,000 deg2). It was carried out in 1965–1980 by B. E. Markarian and his colleagues and resulted in discovery of 1517 UV-excess (Markarian) galaxies. They contain many active galaxies, as well as powerful gamma-, X-ray, IR and radio sources (Mrk 180, 231, 421, 501, etc.), BCDGs (Mrk 116) and interacting/merging systems (Mrk 266, 273, etc.). They led to the classification of Seyfert galaxies into Sy1 and Sy2 and the definition of Starbursts (SB). Several catalogs of Markarian galaxies have been published (Mazzarella & Balzano 1986; Markarian et al. 1989; Bicay et al. 1995; Petrosian et al. 2007) and they are accessible in all corresponding databases. Markarian survey also served as a basis for search for UVX stellar objects (including QSOs and Seyferts), late-type stars and optical identification of IR sources. At present the survey is digitized and DFBS database is available. I will review the main characteristics of the Markarian survey, its comparison with other similar surveys and the importance of Markarian galaxies in modern astrophysics.
The discovery of eight z ~ 6 quasars from Pan-STARRS1
Authors: Bañados E. , Venemans B. P. , Morganson E. , Decarli R. , Walter F. , Chambers K. C. , Rix H-W. , Farina E. P. , Fan X. , Jiang L. , McGreer I. , De Rosa G. , Simcoe R. , Weiß A. , Price P. A. , Morgan J. S. , Burgett W. S. , Greiner J. , Kaiser N. , Kudritzki R.-P. , Magnier E. A. , Metcalfe N. , Stubbs C. W. , Sweeney W. , Tonry J. L. , Wainscoat R. J. , Waters C. 
Published: July 2014

AbstractHigh-redshift quasars are unique probes of the evolution of supermassive black holes and the intergalactic medium at the end of the epoch of reionization. We present the optical spectra of eight new z ~ 6 quasars selected from the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS1). Details of the selection strategy can be found in Bañados et al. (2014). With this work we increase the number of known quasars at z < 5.7 by more than 10%. The quasars discovered here span a large range of luminosities (19.6 ≤ zP1 ≤ 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show weak or no Lyα emission line. We find a larger fraction of weak–line emission quasars than in lower redshift studies, although still based on low number statistics, this may imply that the quasar population could be more diverse than previously thought.
A Deep Narrow Band Imaging Search for CIVλ1548Å and HeIIλ1640Å Emission from Lyman Alpha Blobs
Authors: Arrigoni Battaia Fabrizio , Yang Y. , Hennawi J. F. , Matsuda Y. , Yamada T. , Hayashino T. 
Published: July 2014

AbstractTo study the nature of Lyα blobs (aka LABs), we conduct a deep C IV and He II narrowband imaging survey of 13 Lyα blobs located in SSA22 proto-cluster at z ~ 3.1. We reach the unprecedented sensitivity, 5σ surface brightness limit of 2.1 − 3.4 × 10−18 erg s−1 cm−2 arcsec−2 per 1 arcsec2 aperture for two emission lines. We do not detect any extended C IV and He II emission, placing strong upper limits on the He II/Lyα and C IV/Lyα line ratios. We compare our limits with data in the literature related to the nebulae associated with high-redshift radio galaxies (HzRGs) and quasars, and we recover the data by modeling the LABs as nebulosities powered by a central QSO. For further information see Arrigoni Battaia et al. (2014).
Complex Investigation of SBS Galaxies in Seven Selected Fields
Authors: Hakopian Susanna 
Published: July 2014

AbstractIt is known that the main criterion for the selection of active objects in the First Byurakan, otherwise Markarian survey was the presence of signs of UV-excess in their low-dispersion spectra. Using the presence of emission lines as the second criteria became real during the Second Byurakan survey because of its improved technique. Extended (not stellated) objects, selected with the use of this criterion, made the main part of the separate sample of SBS galaxies. Originally, this sample included 1286 objects, selected in 65 fields of the survey (16 square degree each), to which, with the help of other sources than the survey, there were later added some objects. We studied a subsample of SBS galaxies in seven selected fields (the deepest according to the V/Vmax criterion), including about the third of the whole sample. The first, already completed phase of this program was started with carrying out a follow-up slit spectroscopy of all, about 500 objects, based on observations with long-slit spectrographs with 6m telescope of SAO Russia and 2.6.m telescope of Byurakan. As a result redshifts were determined, as well as spectral classification was made for all of objects, using the scheme adapted to the spectral material. Besides other, obtained data allowed us to estimate the efficiency of used criteria for the selection of galaxies of different classes of starformation and nuclear activity along the full scale of the apparent magnitudes, including close to the limit values (18.5 < mpg < 19.5), etc. The fact that the total area of seven fields as the total number of objects in them comparable with these values for the survey as a whole, allows us to extrapolate the results to the whole sample of galaxies as an upper estimate. The second stage is to conduct detailed studies of individual galaxies in the first place, the most interesting in terms of morphology. They are based on panoramic spectroscopy obtained from observations at 6 m telescope of Russia and 2.6m telescope of Byurakan carried out with multipupil spectrographs MPFS and VAGR, correspondently. Processing of the data obtained for more than twenty objects are at different stages (see arXiv:1403.0127 for extended version).
AGN torus properties with WISE
Authors: Nikutta Robert , Nenkova Maia , Ivezić Željko , Hunt-Walker Nicholas , Elitzur Moshe 
Published: July 2014

AbstractThe Wide-field Infrared Survey Explorer (WISE) has scanned the entire sky with unprecedented sensitivity in four infrared bands, at 3.4, 4.6, 12, and 22 μm. The WISE Point Source Catalog contains more than 560 million objects, among them hundreds of thousands of galaxies with Active Nuclei (AGN). While type 1 AGN, owing to their bright and unobscured nature, are easy to detect and constitute a rather complete and unbiased sample, their type 2 counterparts, postulated by AGN unification, are not as straightforward to identify. Matching the WISE catalog with known QSOs in the Sloan Digital Sky Survey we confirm previous identification of the type 1 locus in the WISE color space. Using a very large database of the popular Clumpy torus models, we find the colors of the putative type 2 counterparts, and also, for the first time, predict their number vs. flux relation that can be expected to be observed in any given WISE color range. This will allow us to put statistically very significant constraints on the torus parameters. Our results are a successful test of the AGN unification scheme.
Dusty Active Galaxies
Authors: Andreasian-Thomas Nora 
Published: July 2014

AbstractMost astronomers know about B. E. Markarians discovery and further study of galaxies with UV excess. It is less known that in 1963 Markarian drew attention to a small group of galaxies with color index-spectral type discrepancy. Early spectral type of these galaxies is combined with large color index (e.g. M82). Later studies showed that galaxies with large intrinsic color indices (CI ≥ 0.85) exhibit properties typical for active galaxies - galaxies with “red excess” are as active as galaxies with UV excess.
A 2.5-5 μm spectroscopic study of hard X-ray selected AGNs with AKARI
Authors: Castro A. , Miyaji T. , Shirahata M. , Oyabu S. , Clark D. , Ichikawa K. , Imanishi M. , Nakagawa T. , Ueda Y. 
Published: July 2014

AbstractWe explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ≲ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 μm PAH luminosity (L3.3μm) as a proxy for star formation activity and hard X-ray luminosity (L14-195keV) as an indicator of the AGN activity. We searched for possible difference of star-formation activity between type 1 (un-absorbed) and type 2 (absorbed) AGNs. Our regression analysis of log L14-195keV versus log L3.3μm shows a positive correlation and the slope seems steeper for type 1/unobscured AGNs than that of type 2/obscured AGNs. The same trend has been found for the log (L14-195keV/MBH) versus log (L3.3μm/MBH) correlation. Our analysis show that the circum-nuclear star-formation is more enhanced in type 2/absorbed AGNs than type 1/un-absorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs.
Analysis and Statistics of the Spectroscopic Sample of Byurakan-IRAS Galaxies
Authors: Harutyunyan Gohar S. , Mickaelian Areg M. 
Published: July 2014

AbstractA summary and general analysis of optical spectroscopic data for 255 Byurakan-IRAS Galaxies (BIG) obtained with BAO 2.6m, SAO 6m, OHP 1.93m telescopes, as well as SDSS DR7, DR8, and DR9 is given. The BIG sample is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra. Among the 1178 objects most are spiral galaxies and there is a number of ULIRGs. All but one have emission lines; we have discovered 68 AGN and composite spectrum objects among them and the others are mostly Starburst Galaxies (SB). All possible physical characteristics have been measured and/or calculated, including physical sizes and optical and IR/FIR luminosities. The masses have been estimated based on mass-luminosity relations for spiral galaxies. As it appears, most of these objects are giant massive galaxies. Various multiwavelength (MW) data have been retrieved from recent catalogues from X-ray to radio and MW SEDs have been built, which have been matched to their optical classifications. Luminosity evolution of these objects has been studies.
Very Long Baseline Interferometry observations: the closest look at the cores of AGN
Authors: Giroletti Marcello , Lico Rocco , Hada Kazuhiro , Giovannini Gabriele 
Published: July 2014

AbstractVery Long Baseline Interferometry (VLBI) provides the highest angular resolution achievable in astronomy, reaching sub-milliarcsecond scales. For radio loud AGNs, this offers the unique opportunity to directly image and monitor the fine details of the jet structure, approaching the event horizon in the nearest and most supermassive black holes, like in M87. After a quick review of various VLBI facilities, we present results from recent VLBI monitoring projects on two remarkable radio and high energy sources: the radio galaxy M87 and the BL Lac object Mrk421. For the latter, we present a detailed analysis of the jet structure in total intensity and polarization through the whole 2011, during which a multi-wavelength campaign took place. We reveal flux density variability but no significant changes in the jet structure. In M87, we detect and follow the evolution of the core and of the jet feature HST-1; we reveal superluminal motion of components within HST-1, with a possible connection between ejection of new such components and the occurrence of very high energy flares. Estimates on the physical parameters for both sources are given (Doppler factor, viewing angle, magnetic field, etc.).
Unveiling the nature of the unidentified gamma-ray sources: blazar counterparts at low radio frequencies
Authors: Massaro Francesco , D'Abrusco R. , Giroletti M. , Paggi A. , Masetti N. , Tosti G. 
Published: July 2014

AbstractAbout one third of the gamma-ray sources detected by Fermi have still no firmly established counterpart at lower energies. Here we propose a new approach to find candidate counterparts for the unidentified gamma-ray sources (UGSs) based on the 325 MHz radio survey performed with Westerbork Synthesis Radio Telescope (WSRT) in the northern hemisphere. First we investigate the low-frequency radio properties of blazars, the largest known population of gamma-ray sources; then we search for sources with similar radio properties combining the information derived from the Westerbork Northern Sky Survey (WENSS) with those of the NRAO VLA Sky survey (NVSS). We present a list of candidate counterparts for 32 UGSs with at least one counterpart in the WENSS. We also performed an extensive research in literature to look for infrared and optical counterparts of the gamma-ray blazar candidates selected with the low-frequency radio observations to confirm their nature. On the basis of our multifrequency research we identify 23 new gamma-ray blazar candidates out of 32 UGSs investigated. I will also present the first analysis of very low frequency radio emission of blazars based on the recent Very Large Array Low-Frequency Sky Survey (VLSS) at 74 MHz. I show that blazars present radio flat spectra when evaluated at 74 MHz, about an order of magnitude in frequency lower than previous analyses. The implications of these findings in the contest of the blazars – radio galaxies connection will be discussed.
Independent estimates of energies of steep-spectrum radio sources
Authors: Miroshnichenko Alla 
Published: July 2014

AbstractWe examine properties of galaxies and quasars with steep low-frequency spectra from the UTR-2 catalogue. The number of the objects have the non-thermal X-ray emission due to the inverse Compton scattering of radio photons of the microwave background by relativistic electrons. So, it is possible to estimate the magnetic field strength and the ratio of energies of the magnetic field and relativistic particles, independently. As we have received the determined values of magnetic field strength are near to one order less than those at the well-known energy equipartition condition. We conclude from the obtained energy ratio that the energy of relativistic particles prevails over the energy of magnetic field in the galaxies and quasars with steep radio spectra.
Investigation of Extragalactic Radio Sources by Cross-Matching of Radio Catalogs
Authors: Abrahamyan Hayk V. , Mickaelian Areg M. 
Published: July 2014

AbstractTo search for variable radio sources, we used two well-known radio catalogs NVSS and FIRST, both providing fluxes at 1400 MHz. Cross-correlation enabled us to find 556,282 radio sources present in both catalogs. Using the 3σ criteria we distinguished 6,301 variable radio sources, and with certain limitations specified the 260 strongest radio variables. We cross-correlated these 260 sources with other catalogs at different wavelengths (APM, SDSS DR10, VCV-13, BZCAT, 2MASS, and WISE). As a result we obtained photometric data for optical, NIR, MIR and radio ranges for these 260 variable radio sources to study them in details.
The Lockman Hole Project: A Multi-frequency Study of the Faint Radio Population down to LOFAR bands
Authors: Guglielmino G. , Prandoni I. , Morganti R. , Heald G. , Mahony E. , van Bemmel I. 
Published: July 2014

AbstractWe are performing a multi-frequency radio analysis of a well-known deep field: the Lockman Hole, which is one of the best studied sky regions in different wavebands. This will provide us with important complementary data (for example redshifts) to the radio data, allowing us to characterize the physical and evolutionary properties of the various classes of sources composing the faint radio population. LOFAR imaging of the Lockman Hole can play an important role in this project, allowing, for the very first time, to observe the sub-mJy source population at very low frequencies (30-200 MHz), where self-absorption phenomena are expected to be very important. Here we present some preliminary results.
The MASIV survey: spectroscopic identifications of compact radio sources
Authors: Pursimo T. , Ojha R. , Jauncey D. , Lovell J. , Dutka M. , Bignall H. , Macquart J.-P. , Rickett B. , Kedziora-Chudczer L. , Koay J. Y. 
Published: July 2014

AbstractInterstellar scintillation (ISS) has been shown to be primarily responsible for the short term intraday variability (IDV) exhibited by extragalactic sources at centimeter wavelengths (e.g. Bignall et al. 2006 and references therein). For a source to scintillate its angular size must be comparable to that of the first Fresnel zone (Narayan 1992) which implies microarcsecond angular sizes for screen distances of tens to hundreds of parsecs. This has the potential to probe within a few light months of the central black hole (Bignall et al. 2006). The aim of the Microarcsecond Scintillation-Induced Variability (MASIV) survey was to provide a catalogue of at least a hundred AGNs that vary on timescales of hours to days to provide the basis of detailed studies of the IDV population drawn from a well-defined sample.
Compton Thick AGN
Authors: Levenson N. A. 
Published: July 2014

AbstractCompton thick active galactic nuclei (AGN), which are obscured by column density NH > 1.5 × 104 cm−2, can be difficult to identify. They are certainly cosmically significant, both in producing the observed cosmic X-ray background, and in providing a location where black hole growth is hidden from view. Here I review some recent results from surveys that provide indications of Compton thick AGN, considering X-ray, radio, and infrared selection techniques. I also offer a caution against using mid-infrared silicate features to measure line-of-sight obscuration to active galactic nuclei. Instead, these features better indicate the geometric distribution of dust that the central engine heats. I conclude that the outstanding problem of Compton thick AGN is not the cases where the obscuration is directly associated with the environment of the active nucleus itself, even in the most obscured examples. Instead, we still risk missing the completely buried AGN, which are obscured by large amounts of gas and dust over large solid angles. The solution to finding Compton thick AGN may be to begin the search based on infrared emission and star formation, and then select for nuclear activity.
Very High Energy gamma-rays from blazars
Authors: Sol Helene 
Published: July 2014

AbstractThe extragalactic very high energy (VHE) gamma-ray sky is dominated at the moment by more than fifty blazars detected by the present imaging atmospheric Cherenkov telescopes (IACT), with a majority (about 90%) of high-frequency peaked BL Lac objects (HBL) and a small number of low-frequency peaked and intermediate BL Lac objects (LBL and IBL) and flat spectrum radio quasars (FSRQ). A significant variability is often observed, with time scales from a few minutes to months and years. The spectral energy distribution (SED) of these blazars typically shows two bumps from the radio to the TeV range, which can usually be described by leptonic or hadronic processes. While elementary bricks of the VHE emission scenarios seem now reasonably well identified, a global picture of these sources, describing the geometry and dynamics of the VHE zone, is not yet available. Multiwavelength monitoring and global alert network will be important to better constrain the picture, especially with the perspective of CTA, a major project of the next generation in ground-based gamma-ray astronomy.