bluuebunny/crossref_metadata_2025 huggingface dataset:
Star Formation in Disks
Authors: Larson Richard B.
Published: March 2016

The basic characteristics of the stellar populations in galaxies are determined by the history of star formation and by the initial mass spectrum with which the stars are formed. Many attempts have been made to model the history of star formation in galaxies using various quasi-theoretical descriptions of star formation, but star formation remains a very poorly understood process and no theoretical understanding with any real predictive power has yet been attained. However, recent work suggests the importance for star formation of some mechanisms that have so far not been very extensively studied, and I shall mention some of these possible processes here, undeveloped though these ideas still are at present.

First, I shall review briefly the observational evidence concerning the history of star formation in galaxies of different Hubble type. Most of the information we have for galaxies other than our own comes from their colors, which can be compared with the predictions of models constructed with various assumed histories of star formation. Ever since the work of Tinsley (1968), it has been clear that most of the observed variation of color with Hubble type can be understood in terms of differing time scales for star formation, the reddest galaxies (E and SO) having formed the bulk of their stars at a relatively early stage, while the much bluer Sc galaxies have formed their stars much more gradually and at a rate that has remained nearly constant up to the present time. Recent studies of normal elliptical galaxies, reviewed by Faber in this volume, confirm that they have no detectable present star formation.
Asteroids: Spins and Shapes
Authors: Lagerkvist Claes-lngvar
Published: March 2016

There is a difference in rotational properties between asteroids of various taxonomic types. The M and CMEU asteroids increase their spin with diameter and rotate much faster than asteroids of types C and S of the same diameter do. There is a difference in spin between the C and S types but the faster spin for the S asteroids larger than 150 km in diameter is probably not statistically significant. For both C and S asteroids the spin increases with diameter, but in a much less pronounced fashion than for types M and CMEU. The curve for the S asteroids is remarkably flat for asteroids smaller than 100 km.

The CMEU asteroids are more irregular than other types of asteroids. Both C and S asteroids have larger amplitudes for diameters about 100 km.

The family asteroids smaller than 100 km in diameter have a faster spin than non-family main-belt asteroids of the same size. Family asteroids show an increase of spin and lightcurve amplitude with decreasing diameter.
Meteorite Orbits from Observations by Camera Networks
Authors: Halliday Ian , Griffin Arthur A. , Blackwell Alan T.
Published: March 2016

Camera networks for the study of bright fireballs now have a history approaching two decades• It was hoped that the networks would produce a statistically significant group of recovered meteorites with accurate orbits. Due to the great difficulty in locating the meteorites from a photographed event, there are still only three meteorites with orbits determined from suitable photographs; Pribram, Lost City and Innisfree (Ceplecha I96I, McCrosky et al. 1971, Halliday et al. 1978, respectively). Networks do, however, provide an alternative approach to the problem. Instead of determining approximate orbits from visual observations of recovered meteorite falls, it is now preferable to use reliable orbits from the camera networks for fireballs which are believed to have dropped meteorites that could not be located, or, that are believed to have been physically identical to meteorites, although no appreciable mass survived the atmospheric flight. This paper will review current knowledge based on this approach to the problem.
Radio Active Nuclei
Authors: Kellermann K. I.
Published: March 2016

For the purpose of this survey we shall use the term radio active nucleus to refer to compact radio sources which are found in galactic nuclei and which show activity either in the form of flux density variations or outward flow of material from the nucleus. There is great similarity between the observed properties of radio active nuclei with those of radio active quasars, and it is widely supposed that the quasar phenomena represents an extreme case of an active galaxy. In this paper however, we shall concentrate on compact radio sources found in the nuclei of identifiable galaxies, and quasars are discussed only to the extent that they help to understand the origin and evolution of radio active galactic nuclei.

Since radio active nuclei are typically in extent, they can be mapped only with VLBI techniques. Detailed maps are available for only a few of the strongest nuclei, but a much larger number can be identified from conventional interferometry with a resolution ~ 1”. In the few radio galaxies where most of the observed radio flux comes from the active nucleus, activity is observed directly on a time scale of months or even weeks. In others, it may be inferred from arguments based on synchrotron lifetime.
What Can We Learn about Contact Binaries with the Help of Far UV and X-Ray Observations?
Authors: Vilhu Osmi
Published: March 2016

The IUE and Einstein satellites have changed the clean and simple contact binary (W UMa-type) surface to a more “dirty” one where spots, flux tubes, coronal loops, flares etc. disturb the stellar image. The situation is, of course, the same for many other active stars as well. Here we discuss some aspects of this increased activity which may be relevant for the contact binary evolutionary theory.
High Velocity Gas in the Galactic Halo and Disk
Authors: de Boer Klaas S.
Published: March 2016

The progress in the understanding of the high velocity component of the interstellar medium is reviewed. Emphasis is on the velocities seen outside the plane of the Milky Way, of gas in the galactic halo.

The extensive measurements of interstellar absorption lines in the late 1930’s demonstrated that the “stationary” lines in stellar spectra were extremely narrow and in many cases showed fine structure at the 10 km/s level. The quantisation of these data had to wait until about 1950. Adams (1949) presented data on Ca II lines toward some 300 stars and his compilation, supplemented with Na I data, led Routly and Spitzer (1952) to investigate the systematics of the Ca and Na abundances. Contrary to the non-solar abundance ratio of the majority of the interstellar clouds, the “high velocity” absorptions, defined by Routly and Spitzer as differing in velocity by more than 20 km/s from the local standard of rest, showed a near solar Ca/Na abundance ratio.
The Dynamics of the Local Supercluster
Authors: Huchra John P.
Published: March 2016

The primary reason for studying the dynamics of the local supercluster is for use as a local cosmological test (Silk 1974 Ap. J. 193, 525, Peebles 1976, Ap. J. 205, 318). In addit ion, the measurement of the mass enclosed in the local supercluster provides one of the best measurements of the M/L of galaxy systems on very large scales - a test of the hypothesis that M/L increases with radius for galaxy systems and thus a measure of the unseen matter (neutrino?) content of the universe.
Earth Rotation Variations from Hours to Centuries
Authors: Dickey Jean O.
Published: March 2016

The study of Earth rotation encompasses the complex nature of orientation changes, the excitation of these changes and their geophysical implications in a broad variety of areas. Studies have embarked on a new era with the advent of highly accurate space geodetic techniques and the increasing availability of complementary geophysical data sets. This paper provides an overview of Earth rotation variations from hours to centuries with a brief discussion of polar motion and nutation results.
Precise Observations of Luni-Solar and Free Core Nutation
Authors: McCarthy D.D. , Luzum B.J.
Published: March 2016

The previous analysis of McCarthy and Luzum (1991b) is repeated using an additional three years of VLBI observations. A new set of empirical corrections to the 1980 IAU Nutation Theory is determined and compared to current geophysical models.
The Effective Temperature Determination
Authors: Cayrel Roger
Published: March 2016

The content of my oral contribution has been reduced here to a guide to the recent litterature on the subject.

The effective temperature of a star can be obtained directly by measuring the total flux received on earth from it, and its angular diameter. In principle interferometrie methods could determine both the limb-darkening law of the stellar disk and the angular diameter of the disk. In practice, in order to obtain a decent accuracy on the angular diameter, interferometrie methods have so far borrowed the limb-darkening law from stellar atmosphere theory, in order to concentrate all the observational information on a single parameter. The total number of stellar diameters and effective temperatures obtained by this basic method remains very small (about 30 stars) and concerns exclusively giant or subgiant stars. The reader is invited to look at the following references and those therein (Di Benedetto 1993, Mozurkewich et al. 1991, Alonso et al. 1994). Smalley and Dworetsky (A&A in press) have reinvestigated the old Code et al. (1976) calibration with more recent spatial UV data, for B, A, and F stars, and have found no significant changes. The accuracy of the basic method is at the best of the order of 1.5 %, and there is a deep need for more data, and for doubling the current accuracy. Actually there is a strong effort for developping interferometry both from the ground (ESO VLTI, USNO astrometric interferometer) andfrom space (OSI project, Colavita et al. 1993; GAIA project at ESA). So there is hope for a not to far future.
Status of Agn Unification Models
Authors: Barthel P.D.
Published: March 2016

Unification of Active Galactic Nuclei is obviously multidimensional. Dimensions include the mass and angular momentum of the postulated central black hole, the mass accretion rate through the accretion disk surrounding the black hole, and the orientation of this central engine plus associated dust with respect to the line of sight (e.g., Blandford 1990). As for orientation related unification, considerable progress has been made over the past decade. This review will deal with this geometric unification.

Mechanisms in AGN include:

1.

relativistic beaming in radio jets (as manifested by rapid variability from radio to ϒ-rays, superluminal motion, synchrotron self-Compton

2.

emission by an optically thick, non-spherical body (e.g., hot accretion disk);

3.

external collimation and shadowing by an anisotropic dust distribution (as manifested by the existence of hidden continua, observed through polarization or photon deficit in extended emission line regions, and hidden broad line regions, observed through polarization or in the less opaque near infrared part of the spectrum).

These anisotropic mechanisms introduce selection biases, they lead to incorrect inferred luminosities and make us overestimate the AGN diversity. They furthermore imply unification at some level.
The FUSE Mission: Atomic Data Needs in the 900–1200 Å Spectral Region
Authors: Sembach Kenneth R.
Published: March 2016

The Far Ultraviolet Spectroscopic Explorer (FUSE) is presently producing high resolution (R ∼ 20,000) absorption-line spectra of astronomical objects ranging from Solar System planets to quasars. The 900-1200 Å spectral region observed by FUSE is exceedingly rich in atomic and molecular transitions arising out of the ground state. It is already clear from early FUSE observations that the atomic data (e.g., oscillator strengths) for some transitions are considerably different than those predicted by theoretical calculations. I briefly describe the most pressing oscillator strength needs in this wavelength range for studies of the interstellar medium.
Comparison of Nutation Theories
Authors: McCarthy Dennis D.
Published: March 2016

Analyses of residuals between VLBI observations and combinations of nutation series show that the MHB 2000 nonrigid-Earth nutation model applied to the REN 2000 rigid-Earth model results in the best fit, and that amplitudes of any possible periodic terms remaining in the observed corrections to the MHB2000 theory could be expected to be less than 0.1 mas.
The Circumstellar Environment of Embedded Massive Stars
Authors: Mundy Lee G. , Wyrowski Friedrich , Watt Sarah
Published: March 2016

Millimeter and submillimeter wavelength images of massive star-forming regions are uncovering the natal material distribution and revealing the complexities of their circumstellar environments on size scales from parsecs to 100’s of AU. Progress in these areas has been slower than for low-mass stars because massive stars are more distant, and because they are gregarious siblings with different evolutionary stages that can co-exist even within a core. Nevertheless, observational goals for the near future include the characterization of an early evolutionary sequence for massive stars, determination if the accretion process and formation sequence for massive stars is similar to that of low-mass stars, and understanding of the role of triggering events in massive star formation.
Disks and Jets in High-Mass Young Stellar Objects
Authors: Cesaroni Riccardo
Published: March 2016

The formation of stars is a complex process which is poorly understood at present, although recently important progress has been made both on a theoretical and observational ground. It is clear that star formation must proceed through contraction of a large molecular clump into a dense optically thick proto-stellar core: the obvious consequence is that conservation of angular momentum must force the material to spin up and flatten. Thus, formation of disks around newly formed stars is a very sensible expectation. Indeed, the recent development of instruments like the Hubble Space Telescope (HST) and the millimeter interferometers has allowed detection of several disks around low-mass young stellar objects (YSOs), such as the Keplerian disk in GG Tau (Guilloteau et al. 1999) and that seen with the HST in HH 30 (Burrows et al. 1996). The situation is quite different for high-mass YSOs. In this case, the evidence for disks is scarce, although a priori one would expect these to be more massive than those in low-mass YSOs and hence easier to detect. Various effects may complicate this simple-minded picture: for instance, magnetic field is likely to play an important role coupling the inner part of the collapsing cloud to its outer layers, thus making angular momentum conservation difficult to apply to any single “portion” of the cloud; depending on the ratio between disk and stellar mass, the disk may be unstable and hence short-lived; the effects of the stellar wind and radiation have to be taken into account; finally, the mass and size of the disk depend on the accretion process, which is not well understood. All these caveats probably explain why disks around massive YSOs are difficult to detect.
Astrometry of Outer Solar System Bodies with Small Telescopes
Authors: Tichá J. , Tichý M.
Published: March 2016

Astrometry for an accurate orbit determination of distant objects is usually made with large telescopes ranging from 2 to 10 meters. In selected cases the bright(er) part of their population has been effectively observed with small 0.6 to 1 meter class telescopes. We point out here methods and techniques used at the Kle Observatory including our results. The extension of this programme using a new larger telescope is in preparation. We also mention a possibility of using some web tools for call for follow-up.
Rotation and Nitrogen Enhancements in Blue Supergiants
Authors: Meynet Georges
Published: March 2016

Rotation brings significant surface He- and N-enhancements. The excesses are higher for higher masses and rotation. Rotating stellar models may account for the nitrogen enhancements observed at the surface of blue supergiants.
On a Physical Mechanism for Extra-Mixing in Globular Cluster Red Giants
Authors: Denissenkov Pavel A. , Tout Christopher A.
Published: March 2016

For the first time we propose a real physical mechanism for extra-mixing in red giants which can quantitatively interpret all the known star-to-star abundance variations in globular clusters. This is Zahn’s mechanism (Zahn 1992; Maeder & Zahn 1998). It considers extra-mixing in a radiative zone of a rotating star as a result of joint operation of meridional circulation and turbulent diffusion.
Earth Orientation since AD 1600
Authors: McCarthy Dennis D.
Published: March 2016

Past endeavors in the field of Earth orientation have provided both service to astronomical users of the data and insight into the physical processes of the planet Earth. Since the study of Earth orientation has required a wide geographic distribution of astronomical observing sites, it has been an area of research that has depended heavily on international cooperation over long intervals of time. Recently, IAU Colloquium 178 pointed out that the need exists to find and collect observations that may have been made before the establishment of the current operational services. Reanalysis of such data could be important in our understanding of the physical processes affecting the Earth. All of these observations need to be analyzed in one system consistent with current definitions and conventions. The history of available observations is reviewed along with the contributions that have been made possible using these data. Possible sources for additional data are suggested.
A Joint Discussion on the Topic of Cold Gas and Dust at High Redshift
Authors: Wilner D.J.
Published: March 2016

The number of spectroscopically confirmed galaxies at high redshift is increasing rapidly, with many being found efficiently by deep optical imaging and color selection. In parallel, a confluence of technical developments is bringing rapid progress to the domain of observations of cold gas and dust at high redshift. Large telescopes operating at high, dry sites, with a new generation of sensitive detectors, together with recent satellite missions, are opening up new areas of study through observations of dust continuum emission and associated atomic and molecular emission and absorption lines. These data bear directly on fundamental questions of cosmic evolution by probing the ordinary cool material that forms stars and fuels active galactic nuclei. Analysis of data from the COBE satellite confirms the presence of a diffuse far-infrared background from a widespread population of distant dusty objects. The global energetics of the optical and far-infrared backgrounds suggest that perhaps half of distant activity may be enshrouded by dust. Understanding the nature and redshifts of the sources responsible for these emissions is profoundly important. The intent of Joint Discussion 9, between Division X (Radio Astronomy) and Division XIII (Galaxies and the Universe), was to provide a forum to present observations from this newly accessible realm and to consider the astrophysical implications.
Io’s Volcanos: Latest Results from Galileo and from the Earth
Authors: Spencer John
Published: March 2016

Three recent close flybys of Io by the Galileo spacecraft, and new observations from the Hubble Space Telescope and ground-based telescopes, have greatly advanced our understanding of Jupiter’s volcanic moon Io. Io’s volcanos are much hotter than previously suspected, perhaps requiring exotic silicate magma compositions. Despite much new data, Io’s largest volcano, Loki, is still poorly understood. New data on Io’s plumes suggest the existence of two types of plumes: primary plumes, relatively rich in S2 gas, which are emitted where magma first reaches the surface, and secondary plumes, more SO2 rich, which result from interaction of lava flows with a volatile-rich substrate.
The Surface and Lower Atmosphere of Titan from HST Observations
Authors: Smith Peter H. , Lemmon M. , Tomasko M.
Published: March 2016

In 1994 the HST camera acquired images of Titan during 14 visits throughout a 16—day rotation period. These images were mosaicked to produce surface maps of albedo variations at several wavelengths (0.67, 0.94, and 1.04 microns) which revealed a bright, continent-sized feature on Titan’s leading face (Smith, Lemmon, & Lorenz 1996). Also, the observing program was designed as a search for clouds and their motions; no clouds were conclusively identified. Other observing sessions in subsequent years performed by our group and others have resulted in numerous observations through WFPC2, STIS, and NICMOS. Additional maps have now been made in the 2—micron region that show a very similar surface albedo to the 0.94—micron map (T. Owen, private communication). Models based on these data sets are used to understand the lower atmosphere and surface as seen through the overlying hazes; seasonal variations resulting in a north-south asymmetry of the haze layer are also being studied.
First Images of Titan at 1.3 Micron with the Adaptive Optics PUEO System at the CFHT
Authors: Coustenis Athena , Gendron Eric , Lai Oliver , Véran Jean-Pierre , Woillez Julien , Combes Michel , Fusco Thierry , Mugnier Laurent
Published: March 2016

The first images of Titan at 1.3 micron were obtained with the PUEO adaptive optics system at the CFHT, on October 26 1998. We have also obtained images of Titan at 1.6 micron. Our diffraction-limited images (about 10 independent resolution elements or 20 pixels on the disk) pertain to Titan’s leading hemisphere. We have used narrow-band filters centered outside (1.29, 1.6 µm) and in the wings (1.18, 1.64 µm) of the methane bands, so as to be able to subtract the atmospheric contribution from our data. Images of Titan’s surface show the large equatorial region to be bright at both wavelengths. Combined with previous spectroscopic and imaging data, our findings are compatible with the presence of a mountainous plateau, covered with bright ice (perhaps methane), near the equator of Titan and with hydrocarbon deposits in the darker areas.
Recycling of Ions in Mercury’s Magnetosphere
Authors: Killen Rosemary , Potter Andrew , Sarantos Menelaos , Reiff Patricia
Published: March 2016

To determine the relative rates of ion recycling to the surface and loss of ions to the solar wind, we followed 3,500 Na ions in a tight grid of magnetic and electric fields at Mercury. We conclude that up to 60% of the photoions launched on the dayside near the surface will re-impact the dayside. For a dawn – dusk electric field, we find that most of the returning ions impact the dayside. This will be the case for a southward IMF. Photoions do not impact the dayside with sufficient energy to cause secondary sputtering, but on the nightside they will be accelerated to keV energies, and may cause secondary sputtering there.
The Role of Magnetic Helicity in Solar Flares
Authors: Linton Mark G.
Published: March 2016

Helicity in coronal magnetic fields, often occurring in the form of twisted or sheared fields, can provide surplus energy which is available for release in solar flares. In this paper, several models of how this extra, non-potential, energy can be released will be reviewed. For example, twisted flux tubes can release excess energy via the kink instability. Or energy can be released via a transfer of helicity between different magnetic tubes. For untwisted field, the mutual helicity between flux tubes provides a measure of the shear in the fields, and therefore how much energy is available for release in a flare. For twisted flux tubes, the twist helicity of each tube in combination with the mutual helicity between the tubes dictate what type of reconnection the tubes can undergo and how much energy is available for release. Measuring the helicity of coronal active regions, and studying how this helicity affects magnetic energy release is therefore vital for our understanding of and our ability to predict solar flares.
Globular Clusters in Early-Type Galaxies with GMOS
Authors: Bridges Terry , Beasley Mike , Faifer Favio , Forbes Duncan , Forte Juan , Gebhardt Karl , Hanes Dave , Sharpies Ray , Zepf Steve
Published: March 2016

We present recent results from our long-term Gemini/GMOS study of globular clusters (GCs) in early-type galaxies. To date, we have obtained photometry and spectroscopy for GCs in NGCs 3379, 4649, 524, 7332, and IC 1459. We find a clear bimodality in the NGC 4649 GC color distribution, with the fraction of blue/red clusters increasing with galacto-centric radius. We derive ages and metallicities for 22 GCs in NGC 3379, finding that most of the clusters appear old (10–15 Gyr); however, there is a group of 4 metal-rich, younger clusters with ages of 2–6 Gyr. The NGC 3379 GC velocity dispersion decreases with radius, as does the inferred (local) mass-to-light ratio: there is no evidence for a dark matter halo in NGC 3379 based on our GC data.
Magnetic Fields in Galaxy Clusters
Authors: Govoni Federica , Murgia Matteo
Published: March 2016

Magnetic fields in galaxy clusters can be investigated using a variety of techniques. Recent studies including radio halos, Inverse Compton hard X-ray emissions and Faraday rotation measure, are briefly outlined. A numerical approach for investigating cluster magnetic fields strength and structure is presented. It consists of producing simulated rotation measure, radio halo images, and radio halo polarization, obtained from 3-dimensional multi-scale cluster magnetic field models, and comparing with observations.
The Formation and Evolution of Star Clusters and Galaxies
Authors: Zepf Stephen E.
Published: March 2016

This paper addresses the questions of what we have learned about how and when dense star clusters form, and what studies of star clusters have revealed about galaxy formation and evolution. One important observation is that globular clusters are observed to form in galaxy mergers and starbursts in the local universe, which both provides constraints on models of globular cluster formation, and suggests that similar physical conditions existed when most early-type galaxies and their globular clusters formed in the past. A second important observation is that globular cluster systems typically have bimodal color distributions. This was predicted by merger models, and indicates an episodic formation history for elliptical galaxies. A third and very recent result is the discovery of large populations of intermediate age globular clusters in several elliptical galaxies through the use of optical to near-infrared colors. These provide an important link between young cluster systems observed in starbursts and mergers and old cluster systems. This continuum of ages of the metal-rich globular cluster systems also indicates that there is no special age or epoch for the formation of the metal-rich globular clusters, which comprise about half of the cluster population. The paper concludes with a brief discussion of recent results on the globular cluster – low-mass X-ray binary connection.
Cepheid Variables in Ecliping Binary Systems
Authors: Welch Douglas
Published: March 2016

Microlensing surveys of the Large and Small Magellanic Clouds have revealed the existence of Type I and II Cepheid variable stars in eclipsing binary systems. In this review I will summarize the state of the known published and unpublished observations of these systems describe what has been learned to date and discuss what the prospects are for extracting additional information from the known systems using future observations. This review will also discuss the known state of searches for RR Lyrae stars in both spectroscopic and eclipsing binaries and suggest strategies for future success in detecting such systems.
Improved Light Curves of LMC Eclipsing Binaries
Authors: Kang Young Woon , Hong Kyungsoo , Lee Woo-Baik , Kim Ho-Il , Oh Kyu-Dong
Published: March 2016

We present accurate BV light curves and continuum energy curves of the EROS eclipsing binaries in the Large Magellanic Cloud to find accurate binary parameters as well as their distances. The observations have been carried out using the 2.1 meter telescope in CASLEO Argentina during Feb. 1-10, 2003. We have concentrated CCD direct observations upon EROS field 1 and 2 to improve the accuracy of light curves of eclipsing binaries in the fields. The spectroscopic observations have been also carried out using the simple dispersion method to get continuum energy curves between wavelengths of 4000-8000 Å for several EROS eclipsing binaries. At first, we determined a combined temperature of both components of each binary system using the continuum. Then, the combined temperature was resolved using the first estimation of the light curve solution. Finally, we determined the photometric solutions of several binaries in the Large Magellanic Cloud.
Detached Binaries in the Large Magellanic Cloud
Authors: Michalska G. , Pigulski A.
Published: March 2016

Analysis of the radial-velocity and light curves of detached eclipsing binaries allows to derive stellar masses and radii and, in consequence, enables to find their distances. The method has been already applied to several LMC binaries, but in order to have the distance to the LMC determined with good accuracy, the parameters need to be known for a larger number of systems. As a first step we present results of the analysis of the photometry of over eighty detached binaries in the LMC selected from the OGLE-II catalog of 53 000 variable star candidates. If possible, we combine the OGLE-II data with the photometry from other projects (MACHO and EROS). As a result, we present the list of brightest eclipsing binaries in the LMC suitable for distance determination.
Comparing Chemical Abundances of the Damped Lyα Systems and Metal-Poor Stars
Authors: Prochaska Jason X.
Published: March 2016

I briefly draw comparisons between the fields of damped Lyα and metal-poor stellar abundances. In particular, I examine their complementary age-metallicity relations and comparisons between the damped Lyα and dwarf galaxy abundance patterns. Regarding the latter, I describe a series of problems concerning associating high z damped Lyα systems with present-day dwarfs.
X-ray and Optical Properties of Radio Jets
Authors: Worrall D.M.
Published: March 2016

Over the last few years the high-quality imaging and spectroscopic data from Chandra and XMM-Newton have added greatly to our knowledge of the physics of radio jets. Supported by optical data, we are now able to understand much about jet energetics. Here I review the current state of knowledge.
The Cosmic Evolution of Quasars
Authors: Jackson Carole , Wall Jasper , Shaver Peter , Kellermann Ken , Hook Isobel
Published: March 2016

The form of the quasar luminosity function and its redshift dependence to z~1 has long been established; powerful evolution is required so that by z=1 there is an increase of order 102 – 103 in the space density of the most luminous sources. However it is more difficult to deduce the form of the LF at high redshifts. In this contribution we discuss how a sample of relatively bright radio sources has been used to determine the high-redshift behavior of the radiodoud quasar luminosity function, and the particular advantages of using a radio-selected sample. Our results illustrate how radio-loud quasar samples can be an efficient probe of the high-redshift. Universe.
Rosetta Asteroid Candidates
Authors: Barucci M. Antonietta , Fulchignoni Marcello , Birlan Mirel , Vernazza Pierre , Dotto Elisabetta , Doressoundiram Alain
Published: March 2016

The new scenario of the Rosetta mission to comet 67/P Churyumov-Gerasimenko (launch on February 2004), includes as baseline the fly-by of one or two asteroids. Several asteroids are now possible fly-by candidates (single or double) within the available resources. Other candidates whose fly-bys require a larger Δv can be also considered if the Rosetta interplanetary orbit insertion will cost less Δv.

All the up to date available information on the possible targets are discussed in this report.
Radar Observations of Near-Earth Asteroids
Authors: Nolan Micael C. , Benner Lance A. , Black Greg , Campbell Don B. , Giorgini Jon D. , Hine Alice A. , Howell Ellen S. , Margot Jean-Luc , Ostro Steven J.
Published: March 2016

The recent upgrade of the Arecibo planetary radar system, combined with the huge increase in the near-Earth asteroid (NEA) discovery rate by large survey programs, has greatly increased our ability to observe these objects with radar. Radar provides size, shape, rotation, and trajectory information, and in most cases is the only ground-based technique that spatially resolves near-Earth objects. While the resolution of radar images (typically 7.5m) is not as high as for the very best spacecraft images, spacecraft can visit only a few such objects, and radar observations greatly increase our understanding of the diversity of near-Earth objects, at orders of magnitude lower cost. The single clearest result of these observations is the great variety of near-Earth objects, with binary systems, very fast and very slow rotations, spheres, “bifurcated” objects, and “shards”, suggesting that a similar variety of production and delivery mechanisms deliver these objects to near-Earth orbit. Spacecraft mission planning should take into account this variety, and concentrate on broad coverage of a wide range of objects.
Comets
Authors: A’Hearn Michael F.
Published: March 2016

Earth-based observations of comets far surpass the ability of in situ observations to understand the range of cometary properties and thus provide unique insight into the relationship between comets and the formation of the solar system. Recent developments in composition have emphasized near-IR and mm-wave data, although optical and ultraviolet data still play crucial roles. Observers now realize the importance of chemistry in the coma. Surveys of nuclear sizes are beginning to provide a real size distribution and we have recent examples of breakup that provide important information on structure.
Astrophysics at X-Ray Spectral Resolution 1000
Authors: Brickhouse Nancy S.
Published: March 2016

The Chandra gratings exceed a resolving power R = 1000, but only at the longest wavelengths and with relatively low effective areas. Recent X-ray observations of cool stars illustrate the problem of line blending at different resolutions and give a good sense of what we will routinely be able to measure with Constellation-X, provided it has high enough spectral resolution. We also expect new diagnostics from weak lines and line profiles. Support for this work is provided by NASA NAS8-39083 to SAO for the CXC and LTSA NAG5-3559.
ACMSA: Antarctic Centre for Millimetre and Sub-millimetre Astrophysics
Authors: Sironi Giorgio
Published: March 2016

A Working Group has been created to study the feasibility of ACMSA: Antarctic Center for Millimetric and Sub-millimetric Astrophysics, an international facility based at Dome Concordia (Dome C).
History of Astrophysics in Antarctica – A Brief Overview
Authors: Indermuehle Balthasar T. , Burton Michael G. , Maddison Sarah T.
Published: March 2016

On examining the historical development of astrophysical science at the bottom of the world from the early 20th century until today we find three temporally overlapping eras of which each has a rather distinct beginning. These are the eras of Astrogeology, High Energy Astrophysics and Photon Astronomy.
Dynamic versus Static Designation
Authors: Pourbaix Dimitri
Published: March 2016

Should the designation of the components of a system reflect its known hierarchy or rather the history of their discovery? With the recent progress in, say, radial velocity techniques, the old famous order in which components were used to be discovered (inner to outer components for spectroscopic systems) is somehow altered. In the past, capital letters were used for visual companions and lower case letters for spectroscopic components and there was almost no overlap between the two groups. The situation has changed from both ends of the orbital period interval. In some rare cases, we think letters should be re-distributed and re-assigned in order to reflect the structure of the system. With an adequate choice of the data structure, such a change of the companion designation is rather straightforward to implement in modern databases (such as SB9). The only foreseen drawback is related to the cross-reference with some old papers: the letter B would not designate the same component in a 1970 paper and in a 2003 one. For instance, the former secondary of an SB2 system might now refer to the unseen companion and an astrometric triple.
Entwicklung und Schwerpunkte in der psychologischen Hochbegabungsforschung
Authors: Preckel Franzis , Krampen Günter
Published: March 2016

Zusammenfassung. Auf der Grundlage einer quantitativen szientometrischen Analyse der deutsch- und englischsprachigen Publikationen zum Thema Hochbegabung aus den deutschsprachigen Ländern (PSYNDEX) und der Publikationen aus den primär angloamerikanischen Ländern (PsycINFO) analysieren wir Entwicklung und Schwerpunkte der psychologischen Hochbegabungsforschung von 1980 bis 2014. Im Vergleich liegt die Anzahl dieser Publikationen (PSYNDEX: 1.066; PsycINFO: 8.572) bei einem Fünftel der Menge zum Thema Geistige Behinderung / Intellektuelle Entwicklungsstörung. Die Gesamtmenge an Publikationen zu Hochbegabung zeigt in beiden Datenbanken einen Boom in den 1980er Jahren sowie seit 2000 einen erneuten deutlichen Zuwachs. Der Anteil empirischer Arbeiten fällt mit 38 % nach PSYNDEX im internationalen Vergleich (54 % nach PsycINFO) geringer aus und ist seit 2000 eher konstant, während er bei englischsprachigen Publikationen leicht ansteigt. Circa 80 % aller Publikationen beschäftigen sich mit Hochbegabten im Schulalter (6 – 17 Jahre), während das Vorschul- sowie das Erwachsenenalter wenig Berücksichtigung finden. Die Publikationen fokussieren vor allem allgemein kognitive, schulische, mathematische, sportliche und musikalische Fähigkeiten, während sich nur wenige bis gar keine Publikationen zu z. B. kreativer, verbaler, nonverbaler oder figural-räumlicher Hochbegabung finden. Implikationen für die Hochbegabungsforschung werden diskutiert.
Blood-based biomarkers of age-associated epigenetic changes in human islets associate with insulin secretion and diabetes
Authors: Bacos Karl , Gillberg Linn , Volkov Petr , Olsson Anders H , Hansen Torben , Pedersen Oluf , Gjesing Anette Prior , Eiberg Hans , Tuomi Tiinamaija , Almgren Peter , Groop Leif , Eliasson Lena , Vaag Allan , Dayeh Tasnim , Ling Charlotte
Published: March 2016

Aging associates with impaired pancreatic islet function and increased type 2 diabetes (T2D) risk. Here we examine whether age-related epigenetic changes affect human islet function and if blood-based epigenetic biomarkers reflect these changes and associate with future T2D. We analyse DNA methylation genome-wide in islets from 87 non-diabetic donors, aged 26–74 years. Aging associates with increased DNA methylation of 241 sites. These sites cover loci previously associated with T2D, for example,KLF14. Blood-based epigenetic biomarkers reflect age-related methylation changes in 83 genes identified in human islets (for example,KLF14, FHL2, ZNF518BandFAM123C) and some associate with insulin secretion and T2D. DNA methylation correlates with islet expression of multiple genes, includingFHL2,ZNF518B, GNPNAT1andHLTF.Silencing these genes in β-cells alter insulin secretion. Together, we demonstrate that blood-based epigenetic biomarkers reflect age-related DNA methylation changes in human islets, and associate with insulin secretionin vivoand T2D.
Identification of plant vacuolar transporters mediating phosphate storage
Authors: Liu Tzu-Yin , Huang Teng-Kuei , Yang Shu-Yi , Hong Yu-Ting , Huang Sheng-Min , Wang Fu-Nien , Chiang Su-Fen , Tsai Shang-Yueh , Lu Wen-Chien , Chiou Tzyy-Jen
Published: March 2016

Plant vacuoles serve as the primary intracellular compartments for inorganic phosphate (Pi) storage. Passage of Pi across vacuolar membranes plays a critical role in buffering the cytoplasmic Pi level against fluctuations of external Pi and metabolic activities. Here we demonstrate that the SPX-MFS proteins, designated as PHOSPHATE TRANSPORTER 5 family (PHT5), also named Vacuolar Phosphate Transporter (VPT), function as vacuolar Pi transporters. Based on 31P-magnetic resonance spectroscopy analysis, Arabidopsis pht5;1 loss-of-function mutants accumulate less Pi and exhibit a lower vacuolar-to-cytoplasmic Pi ratio than controls. Conversely, overexpression of PHT5 leads to massive Pi sequestration into vacuoles and altered regulation of Pi starvation-responsive genes. Furthermore, we show that heterologous expression of the rice homologue OsSPX-MFS1 mediates Pi influx to yeast vacuoles. Our findings show that a group of Pi transporters in vacuolar membranes regulate cytoplasmic Pi homeostasis and are required for fitness and plant growth.
Phosphorylation of EB2 by Aurora B and CDK1 ensures mitotic progression and genome stability
Authors: Iimori Makoto , Watanabe Sugiko , Kiyonari Shinichi , Matsuoka Kazuaki , Sakasai Ryo , Saeki Hiroshi , Oki Eiji , Kitao Hiroyuki , Maehara Yoshihiko
Published: March 2016

Temporal regulation of microtubule dynamics is essential for proper progression of mitosis and control of microtubule plus-end tracking proteins by phosphorylation is an essential component of this regulation. Here we show that Aurora B and CDK1 phosphorylate microtubule end-binding protein 2 (EB2) at multiple sites within the amino terminus and a cluster of serine/threonine residues in the linker connecting the calponin homology and end-binding homology domains. EB2 phosphorylation, which is strictly associated with mitotic entry and progression, reduces the binding affinity of EB2 for microtubules. Expression of non-phosphorylatable EB2 induces stable kinetochore microtubule dynamics and delays formation of bipolar metaphase plates in a microtubule binding-dependent manner, and leads to aneuploidy even in unperturbed mitosis. We propose that Aurora B and CDK1 temporally regulate the binding affinity of EB2 for microtubules, thereby ensuring kinetochore microtubule dynamics, proper mitotic progression and genome stability.
Serum complement C3 levels are associated with nonalcoholic fatty liver disease independently of metabolic features in Chinese population
Authors: Xu Chengfu , Chen Yi , Xu Lei , Miao Min , Li Youming , Yu Chaohui
Published: March 2016

Serum complement C3 levels are closely associated with obesity and related metabolic disorders. This study aimed to investigate the association between serum complement C3 levels with non-alcoholic fatty liver disease (NAFLD). A cross-sectional study was performed among adults who took their annual health examinations at Zhenhai Lianhua Hospital, Ningbo, China during 2014. We included 7540 participants (5069 men and 2471 women) in this study. NAFLD patients had higher serum complement C3 levels (P < 0.001) and these levels were positively associated with both NAFLD prevalence and severity (P < 0.001). The above association remains true among lean and metabolic syndrome-free participants. Multivariable regression analysis showed that serum complement C3 was independently associated with risk for NAFLD (OR = 5.231; 95% CI: 3.169–8.635). Serum complement C3 level is positively associated with prevalence and severity of NAFLD and this association is independent of obesity and metabolic syndrome.
Fine particulate (PM2.5) dynamics during rapid urbanization in Beijing, 1973–2013
Authors: Han Lijian , Zhou Weiqi , Li Weifeng
Published: March 2016

PM2.5 has been given special concern in recent years when the air quality monitoring station started recording. However, long-term PM2.5 concentration dynamic analysis cannot be taken with the limited observations. We therefore estimated the PM2.5 concentration using meteorological visibility data in Beijing. We found that 71 ± 17% of PM10 were PM2.5, which contributed to visibility impairment (y = 332.26e−0.232x; R2 = 0.75, P < 0.05). We then reconstructed a time series of annual PM2.5 from 1973 to 2013 and examined its relationship with urbanization by indicators of population, gross domestic production (GDP), energy consumption and number of vehicles. Concluded that 1) Meteorological conditions were not the major cause of PM2.5 increase from 1973 to 2013; 2) With population and GDP growth, PM2.5 increased significantly (R2 = 0.5917, P < 0.05; R2 = 0.5426, P < 0.05); 3) Intensive human activity could change air quality in a short period, as observed changes in the correlations of PM2.5 concentration with energy consumption and number of vehicles before and after 2004, respectively. The success of this research provides an easy way in reconstructing long-term PM2.5 concentration with limited PM2.5 observation and meteorological visibility and insight the impact of urbanization on air quality.
Mutant GDF5 enhances ameloblast differentiation via accelerated BMP2-induced Smad1/5/8 phosphorylation
Authors: Liu Jia , Saito Kan , Maruya Yuriko , Nakamura Takashi , Yamada Aya , Fukumoto Emiko , Ishikawa Momoko , Iwamoto Tsutomu , Miyazaki Kanako , Yoshizaki Keigo , Ge Lihong , Fukumoto Satoshi
Published: March 2016

Bone morphogenetic proteins (BMPs) regulate hard tissue formation, including bone and tooth. Growth differentiation factor 5 (GDF5), a known BMP, is expressed in cartilage and regulates chondrogenesis and mutations have been shown to cause osteoarthritis. Notably, GDF5 is also expressed in periodontal ligament tissue; however, its role during tooth development is unclear. Here, we used cell culture andin vivoanalyses to determine the role of GDF5 during tooth development. GDF5 and its associated BMP receptors are expressed at the protein and mRNA levels during postnatal tooth development, particularly at a stage associated with enamel formation. Furthermore, whereas BMP2 was observed to induce evidently the differentiation of enamel-forming ameloblasts, excess GDF5 induce mildly this differentiation. A mouse model harbouring a mutation in GDF5 (W408R) showed enhanced enamel formation in both the incisors and molars, but not in the tooth roots. Overexpression of the W408R GDF5 mutant protein was shown to induce BMP2-mediated mRNA expression of enamel matrix proteins and downstream phosphorylation of Smad1/5/8. These results suggest that mutant GDF5 enhances ameloblast differentiation via accelerated BMP2-signalling.
KIR2DL2/2DL3-E35 alleles are functionally stronger than -Q35 alleles
Authors: Bari Rafijul , Thapa Rajoo , Bao Ju , Li Ying , Zheng Jie , Leung Wing
Published: March 2016

KIR2DL2 and KIR2DL3 segregate as alleles of a single locus in the centromeric motif of the killer cell immunoglobulin-like receptor (KIR) gene family. Although KIR2DL2/L3 polymorphism is known to be associated with many human diseases and is an important factor for donor selection in allogeneic hematopoietic stem cell transplantation, the molecular determinant of functional diversity among various alleles is unclear. In this study we found that KIR2DL2/L3 with glutamic acid at position 35 (E35) are functionally stronger than those with glutamine at the same position (Q35). Cytotoxicity assay showed that NK cells from HLA-C1 positive donors with KIR2DL2/L3-E35 could kill more target cells lacking their ligands than NK cells with the weaker -Q35 alleles, indicating better licensing of KIR2DL2/L3+ NK cells with the stronger alleles. Molecular modeling analysis reveals that the glutamic acid, which is negatively charged, interacts with positively charged histidine located at position 55, thereby stabilizing KIR2DL2/L3 dimer and reducing entropy loss when KIR2DL2/3 binds to HLA-C ligand. The results of this study will be important for future studies of KIR2DL2/L3-associated diseases as well as for donor selection in allogeneic stem cell transplantation.