bluuebunny/crossref_metadata_2025_split huggingface dataset:
Definition and realization of the celestial intermediate reference system
Authors: Capitaine N. 
Published: July 2008

AbstractThe transformation between the International Terrestrial Reference System (ITRS) and the Geocentric Celestial Reference system (GCRS) is an essential part of the models to be used when dealing with Earth's rotation or when computing directions of celestial objects in various systems. The 2000 and 2006 IAU resolutions on reference systems have modified the way the Earth orientation is expressed and adopted high accuracy models for expressing the relevant quantities for the transformation from terrestrial to celestial systems. First, the IAU 2000 Resolutions have refined the definition of the astronomical reference systems and transformations between them and adopted the IAU 2000 precession-nutation. Then, the IAU 2006 Resolutions have adopted a new precession model that is consistent with dynamical theories and have addressed definition, terminology or orientation issues relative to reference systems and time scales that needed to be specified after the adoption of the IAU 2000 resolutions. These in particular provide a refined definition of the pole (the Celestial intermediate pole, CIP) and the origin (the Celestial intermediate origin, CIO) on the CIP equator as well as a rigorous definition of sidereal rotation of the Earth. These also allow an accurate realization of the celestial intermediate system linked to the CIP and the CIO that replaces the classical celestial system based on the true equator and equinox of date. This talk explains the changes resulting from the joint IAU 2000/2006 resolutions and reviews the consequences on the concepts, nomenclature, models and conventions in fundamental astronomy that are suitable for modern and future realizations of reference systems. Realization of the celestial intermediate reference system ensuring a micro-arc-second accuracy is detailed.
Gravitational bending of light by planetary multipoles and its measurement with microarcsecond astronomical interferometers
Authors: Kopeikin S. , Makarov V. 
Published: July 2008

AbstractGeneral relativistic deflection of light by mass, dipole, and quadrupole moments of gravitational field of a moving massive planet in the Solar system is derived in the approximation of the linearized Einstein equations. All terms of the order of 1 μas and larger are taken into account, parameterized, and classified in accordance with their physical origin. We discuss the observational capabilities of the near-future optical and radio interferometers for detecting the Doppler modulation of the radial deflection, and the dipolar and quadrupolar light-ray bending by Jupiter and Saturn.
Light deflection in the second post-Newtonian approximation of scalar-tensor theory of gravity
Authors: Dong P. , Ni W. T. 
Published: July 2008

AbstractIn this paper, we use the metric coefficients and the equation of motion in the 2nd post-Newtonian approximation in scalar-tensor theory including intermediate range gravity to derive the deflection of light and compare it with previous works. These results will be useful for precision astrometry missions like Gaia, SIM, and LATOR (Laser Astrometric Test Of Relativity) which aim at astrometry with micro-arcsecond and nano-arcsecond accuracies and a need for the 2nd post-Newtonian framework and ephemeris to determine the stellar and spacecraft positions.
Direct contribution of the surface layers to the Earth's dynamical flattening
Authors: Liu Y. , Huang C. L. 
Published: July 2008

AbstractThe global dynamic flattening (H) is an important quantity in research of rotating Earth. Precession observations give Hobs = 0.0032737 ≈ 1/305.5. We recalculate the geometrical flattening profile of the Earth interior from potential theory in hydrostatic equilibrium. Results coincide with that of Denis (1989). We derive expression for H to the third-order accuracy and obtain HPREM = 1/308.5. This matches similar studies, in which there is a difference about 1% between this and the observed value. In order to understand where this difference comes from, we replace the homogenous outermost crust and oceanic layers in PREM with some real surface layers data, such as oceanic layer (ECCO), topography data (GTOPO30), crust data (CRUST2.0) and mixed data (ETOPO5). Our results deviate from the observed value more than HPREM. These results verify the isostasy theory indirectly and may imply that the “positive” effects from such as mantle circulation associated with the density anomalies maybe larger than thought before.
Preliminary result of the Earth's free oscillations by Galerkin method
Authors: Zhang M. , Seyed-Mahmoud B. , Huang C. L. 
Published: July 2008

AbstractWe use a Galerkin method to compute the eigenfunctions and eigenperiods of some of the Earths spheroidal and toroidal modes. The boundary conditions are treated using a Tau method. We show that for a realistic Earth model the difference between the computed and observed periods is less than 1.4%. We conclude that a Galerkin method may be an effective tool for the studies of the Earth's normal modes.
Open clusters: their kinematics and metallicities
Authors: Chen L. , Hou J. L. , Zhao J. L. , de Grijs R. 
Published: July 2008

AbstractWe review our work on Galactic open clusters in recent years, and introduce our proposed large program for the LOCS (LAMOST Open Cluster Survey). First, based on the most complete open clusters sample with metallicity, age and distance data as well as kinematic information, some preliminary statistical analysis regarding the spatial and metallicity distributions is presented. In particular, a radial abundance gradient of −0.058±0.006 dex kpc−1 is derived. By dividing clusters into the age groups we show that the disk abundance gradient was steeper in the past. Secondly, proper motions, membership probabilities, and velocity dispersions of stars in the regions of two very young open clusters are derived. Both clusters show clear evidence of mass segregation, which provides support for the “primordial” mass segregation scenario. Based on the advantages of the forthcoming LAMOST facility, we have proposed a detailed open cluster survey with LAMOST (the LOCS). The aim, feasibility, and the present development of the LOCS are briefly summarized.
Distances and ages of globular clusters
Authors: Chaboyer B. 
Published: July 2008

AbstractAs the oldest objects whose ages can be accurately determined, Galactic globular clusters can be used to establish the minimum age of the universe (and hence, to constrain cosmological models) and to study the early formation history of the Milky Way. The largest uncertainty in the determination of globular cluster ages is the distance scale. The current uncertainty in the distances to globular clusters is ~ 6%, which leads to a 13% uncertainty in the absolute ages of globular clusters. I am the PI on a SIM-Planetquest key project to determine the distances of 21 globular clusters with an accuracy of ranging from 1 to 4%. This will lead to age determinations accurate to 5 − 9%. The mean age of the oldest, most metal-poor globular clusters will be determined with an accuracy of ±3%.
Precision astrometry, galactic mergers, halo substructure and local dark matter
Authors: Majewski S. R. 
Published: July 2008

AbstractThe concordance Cold Dark Matter model for the formation of structure in the Universe, while remarkably successful at describing observations on large scales, has a number of problems on galactic scales. The Milky Way and its satellite system provide a key laboratory for exploring dark matter (DM) in this regime, but some of the most definitive tests of local DM await microarcsecond astrometry, such as will be delivered by the Space Interferometry Mission (SIM Planetquest). I discuss several tests of Galactic DM enabled by future microarcsecond astrometry.
The transition between the thick and thin Galactic disks
Authors: Haywood M. 
Published: July 2008

AbstractWe study the transition between the thick and thick disks using solar neighbourhood data, focusing in particular on the status of local metal-poor thin disk stars ([Fe/H]<−0.3 dex, [α/Fe]<0.1 dex). The orbital properties of these stars, which are responsible for the hiatus in metallicity between the two disks, suggest that they most likely originate from the outer Galactic thin disk. It implies that the transition between the two stellar populations at a solar galactocentric distance must have occurred at a metallicity of about −0.3 dex. Transition stars at this metallicity are in fact present in local samples and fill the gap in α-element between the thick and thin disks. These results imply that, at least from the local data, there is a clear evolutionary link between the thick and thin disks.
Understanding our Galaxy: from the center to outskirts
Authors: Shen Z. Q. , Xu Y. , Han J. L. , Zheng X. W. 
Published: July 2008

AbstractWe describe the efforts to understand our Milky Way Galaxy, from its center to outskirts, including (1) the measurements of the intrinsic size of the galactic center compact radio source Sgr A*; (2) the determination of the distance from the Sun to the Perseus spiral arm; and (3) the revealing of large scale global magnetic fields of the Galaxy.With high-resolution millimeter-VLBI observations, Shen et al. (2005) have measured the intrinsic size of the radio-emitting region of the galactic center compact radio source Sgr A* to be only 1 AU in diameter at 3.5 mm. When combined with the lower limit on the mass of Sgr A*, this provides strong evidence for Sgr A* being a super-massive black hole. Comparison with the intrinsic size detection at 7 mm indicates a frequency-dependent source size, posing a tight constraint on various theoretical models.With VLBI phase referencing observations, Xu et al. (2006) have measured the trigonometric parallax of W3OH in the Perseus spiral arm with an accuracy of 10 μas and also its absolute velocity with an accuracy of 1 km s−1. This demonstrates the capability of probing the structure and kinematics of the Milky Way by determining distances to 12 GHz methanol (CH3OH) masers in star forming regions of distant spiral arms and Milky Way's outskirts.With pulsar dispersion measures and rotation measures, Han et al. (2006) can directly measure the magnetic fields in a very large region of the Galactic disk. The results show that the large-scale magnetic fields are aligned with the spiral arms but reverse their directions many times from the most inner Norma arm to the outer Perseus arm.
Precise measurement of the dynamical masses in AB Doradus
Authors: Guirado J. C. , Martí-Vidal I. , Marcaide J. M. 
Published: July 2008

AbstractThe radio stars ABDor A and ABDor B (=Rst137B) are the main components of the ABDoradus system. Both stars are double (ABDor A/ABDor C and ABDor Ba/ABDor Bb) and usual targets of astrometric instruments at optical (Hipparcos), infrared (VLT), and radio (VLBI) wavelengths. From a combination of all astrometric data available, we have obtained precise limits to the dynamical mass of both binaries in AB Doradus. The determination of the mass of ABDor C (0.090±0.003 M⊙) is important, since this object constitutes one of the few calibration points used to test theoretical evolutionary models of low-mass young stars. Follow-up observations both in radio (VLBI) and optical wavelengths (VLT) should determine with high precision the dynamical mass of the four components of this system.
Dynamics of particles in slowly rotating black holes with dipolar halos
Authors: Han W. B. 
Published: July 2008

AbstractIn general, the model of galaxy assumes a central huge black hole surrounded by a massive halo, disk or ring. In this paper, we investigate the gravitational field structure of a slowly rotating black hole with a dipolar halo, and the dynamics and chaos of test particles moving in it. Using Poincaré sections and fast Lyapunov indicator (FLI) in general relativity, we investigate chaos under different dynamical parameters, and find that the FLI is suitable for detecting chaos and even resonant orbits.
Stellar parameters through high precision parallaxes
Authors: Jordi C. , Fabricius C. , Carrasco J. M. , Figueras F. , Masana E. , Voss H. , Luri X. 
Published: July 2008

AbstractBefore Hipparcos, the determination of absolute luminosity was usually done through calibrations based on a few stellar parallaxes measured at the highest precision. The Hipparcos mission meant a giant step on the knowledge of luminosities and fine structure of the HR diagram. The Gaia mission will go an enormous step further. Besides luminosities, Gaia will allow us to derive other stellar parameters like temperature and extinction, gravity, chemical composition, age and mass by the combination of astrometric and spectrometric data. Through simulations during the mission preparation, it has been shown that the astrometric parallax information is essential to deal with the degeneracy between gravity and chemical composition ([Fe/H] and [α/Fe]), that cannot be treated using only spectrophotometry. We show the expected HR diagram for the Gaia domain and the accuracies of stellar parameters.
Astrometry course at University of Tokyo
Authors: Fukushima T. 
Published: July 2008

AbstractThe astrometry course at Department of Astronomy, University of Tokyo, is reviewed as an example of educational efforts for top-class students, the possible candidates of professional astronomers, in Japan. The method of teaching is unique in the sense that it gives lectures by using incomplete text books both as MS Powerpoint slides posted at a web site, http://chiron.mtk.nao.ac.jp/~toshio/education.html, and as printed materials in the form of self-study notebooks. Also there are self-study notebooks on the related issues; the courses of relativistic astrometry, of rotational motions, of numerical astronomy, and of orbital motions, the last of which is under development.
Astrometric education in China
Authors: Jin W. J. , Zhu Z. 
Published: July 2008

AbstractWith measuring precision on the order of milli-arcseconds for ground-based survey facilities or even micro-arcseconds for space astrometric satellites, the importance of astrometric education continues to be important. The content of astrometric courses in China during the past fifteen years is reviewed and the current astrometric courses for undergraduate and graduate students at universities and observatories in China are presented. Finally the improvements of astrometric education in content and teaching methods are suggested.
ELSA – training the next generation of space astrometrists
Authors: Lindegren L. , Bijaoui A. , Brown A. G. A. , Drimmel R. , Eyer L. , Jordan S. , Kontizas M. , van Leeuwen F. , Muinonen K. , Pourbaix D. , Torra J. , Turon C. , de Vries J. , Zwitter T. 
Published: July 2008

AbstractELSA (European Leadership in Space Astrometry) is an EU-funded research project 2006–2010, contributing to the scientific preparations for the Gaia mission while training young researchers in space astrometry and related subjects. Nine postgraduate (PhD) students and five postdocs have been recruited to the network. Their research focuses on the principles of global astrometric, photometric, and spectroscopic measurements from space, instrument modelling and calibration, and numerical analysis tools and data processing methods relevant for Gaia.
China NEO Survey Telescope and its preliminary achievement
Authors: Zhao H. B. , Yao J. S. , Lu H. 
Published: July 2008

AbstractIn recent years, there has been an increasing appreciation for the hazards posed by Near Earth Objects (NEOs), those asteroids and periodic comets whose motions can bring them into the Earth's neighborhood. An NEO Survey Telescope (NEOST) was built in China to be taken part in the international NEO joint survey. This telescope is a 1.0/1.2m Schmidt telescope, equipped with a 4K by 4K CCD detector with a drift-scanning function. After adjusting the telescope and test observations, in December 2006 the NEOST began its NEO survey program. We have found 188 new asteroids including an NEO – 2007 JW2 and one periodic comet –P/2007 S1 (Zhao).
Self‐Assembled Poly(butadiene)‐b‐poly(ethylene oxide) Polymersomes as Paclitaxel Carriers
Authors: Li Shuliang , Byrne Belinda , Welsh JoEllen , Palmer Andre F. 
Published: July 2008

AbstractIn this work, self‐assembled poly(butadiene)‐ b‐poly(ethylene oxide) (PB‐PEO) polymersomes (polymer vesicles) and worm micelles were evaluated as paclitaxel carriers. Paclitaxel was successfully incorporated into PB‐PEO polymersomes and worm micelles. The loading capacity of paclitaxel inside PB‐PEO colloids ranged from 6.7% to 13.7% w/w, depending on the morphology of copolymer colloids and the molecular weight of diblock copolymer. Paclitaxel loaded OB4 (PB219‐PEO121) polymersome formulations were colloidally stable for 4 months at 4 °C and exhibited slow steady release of paclitaxel over a 5 week period at 37 °C. Evaluation of the in vitro cytotoxicity of paclitaxel‐polymersome formulations showed that the ability of paclitaxel‐loaded polymersomes to inhibit proliferation of MCF‐7 human breast cancer cells was less compared to paclitaxel alone. By increasing the concentration of paclitaxel in polymersomes from 0.02 to 0.2 μg/mL, paclitaxel‐polymersome formulations showed comparable activity in inhibiting the growth of MCF‐7 cells. Taken together, these results demonstrate that paclitaxel‐polymersomes have desirable restrained release profile and exhibit long‐term stability.
Ventral Posterior Complex of the Thalamus
Authors:   Allen Institute for Brain Science, Solan Beth , Ng Lydia , Morris John 
Published: July 2008

AbstractThis report contains a gene expression summary of the ventral posterior complex of the thalamus (VP), derived from the Allen Brain Atlas (ABA) in-situ hybridization (ISH) mouse data set. The structure’s location and morphological characteristics in the mouse brain are described using the Nissl data found in the Allen Reference Atlas. Using an established algorithm, the expression values of the VP were compared to the values of the macro/parent-structure, in this case the thalamus, for the purpose of extracting regionally specific gene expression data. The highest ranking ratios were then manually curated and verified. The 50 Select Genes were compiled for expression characterization. The experimental data for each gene may be accessed via the links provided; complementary sagittal data may also be accessed using the ABA. Correlation between gene expression in the VP and the rest of the brain, across all genes in the coronal dataset (~4300 genes), were derived computationally and are presented below. A gene ontology table (derived from DAVID Bioinformatics Resources 2007) is also included, highlighting possible functions of these 50 Select Genes.
Mg2+-dependent ATP occlusion at the first nucleotide-binding domain (NBD1) of CFTR does not require the second (NBD2)
Authors: Aleksandrov Luba , Aleksandrov Andrei , Riordan John R. 
Published: July 2008

ATP binding to the first and second NBDs (nucleotide-binding domains) of CFTR (cystic fibrosis transmembrane conductance regulator) are bivalent-cation-independent and -dependent steps respectively [Aleksandrov, Aleksandrov, Chang and Riordan (2002) J. Biol. Chem. 277, 15419–15425]. Subsequent to the initial binding, Mg2+ drives rapid hydrolysis at the second site, while promoting non-exchangeable trapping of the nucleotide at the first site. This occlusion at the first site of functional wild-type CFTR is somewhat similar to that which occurs when the catalytic glutamate residues in both of the hydrolytic sites of P-glycoprotein are mutated, which has been proposed to be the result of dimerization of the two NBDs and represents a transient intermediate formed during ATP hydrolysis [Tombline and Senior (2005) J. Bioenerg. Biomembr. 37, 497–500]. To test the possible relevance of this interpretation to CFTR, we have now characterized the process by which NBD1 occludes [32P]N3ATP (8-azido-ATP) and [32P]N3ADP (8-azido-ADP). Only N3ATP, but not N3ADP, can be bound initially at NBD1 in the absence of Mg2+. Despite the lack of a requirement for Mg2+ for ATP binding, retention of the NTP at 37 °C was dependent on the cation. However, at reduced temperature (4 °C), N3ATP remains locked in the binding pocket with virtually no reduction over a 1 h period, even in the absence of Mg2+. Occlusion occurred identically in a ΔNBD2 construct, but not in purified recombinant NBD1, indicating that the process is dependent on the influence of regions of CFTR in addition to NBD1, but not NBD2.
RNA interference targeting the ACE gene reduced blood pressure and improved myocardial remodelling in SHRs
Authors: He Junhua , Bian Yunfei , Gao Fen , Li Maolian , Qiu Ling , Wu Weidong , Zhou Hua , Liu Gaizhen , Xiao Chuanshi 
Published: July 2008

The purpose of the present study was to investigate the effects on blood pressure and myocardial hypertrophy in SHRs (spontaneously hypertensive rats) of RNAi (RNA interference) targeting ACE (angiotensin-converting enzyme). SHRs were treated with normal saline as vehicle controls, with Ad5-EGFP as vector controls, and with recombinant adenoviral vectors Ad5-EGFP-ACE-shRNA, carrying shRNA (small hairpin RNA) for ACE as ACE-RNAi. WKY (Wistar–Kyoto) rats were used as normotensive controls treated with normal saline. The systolic blood pressure of the caudal artery was recorded. Serum levels of ACE and AngII (angiotensin II) were determined using ELISA. ACE mRNA and protein levels were determined in aorta, myocardium, kidney and lung. On day 32 of the experiment, the heart was pathologically examined. The ratios of heart weight/body weight and left ventricular weight/body weight were calculated. The serum concentration of ACE was lower in ACE-RNAi rats (16.37±3.90 ng/ml) compared with vehicle controls and vector controls (48.26±1.50 ng/ml and 46.67±2.82 ng/ml respectively; both P&lt;0.05), but comparable between ACE-RNAi rats and WKY rats (14.88±3.15 ng/ml; P&gt;0.05). The serum concentration of AngII was also significantly lower in ACE-RNAi rats (18.24±3.69 pg/ml) compared with vehicle controls and vector controls (46.21±5.06 pg/ml and 44.93±4.12 pg/ml respectively; both P&lt;0.05), but comparable between ACE-RNAi rats and WKY rats (16.06±3.11 pg/ml; P&gt;0.05). The expression of ACE mRNA and ACE protein were significantly reduced in the myocardium, aorta, kidney and lung in ACE-RNAi rats compared with that in vehicle controls and in vector controls (all P&lt;0.05). ACE-RNAi treatment resulted in a reduction in systolic blood pressure by 22±3 mmHg and the ACE-RNAi-induced reduction lasted for more than 14 days. In contrast, blood pressure was continuously increased in the vehicle controls as well as in the vector controls. The ratios of heart weight/body weight and left ventricular weight/body weight were significantly lower in ACE-RNAi rats (3.12±0.23 mg/g and 2.24±0.19 mg/g) compared with the vehicle controls (4.29±0.24 mg/g and 3.21±0.13 mg/g; P&lt;0.05) and the vector controls (4.43±0.19 mg/g and 3.13±0.12 mg/g; P&lt;0.05). The conclusion of the present study is that ACE-silencing had significant antihypertensive effects and reversed hypertensive-induced cardiac hypertrophy in SHRs, and therefore RNAi might be a new strategy in controlling hypertension.