bluuebunny/crossref_metadata_2025 huggingface dataset:
Cannabinoid‐induced effects on the nociceptive system: A neurophysiological study in patients with secondary progressive multiple sclerosis
Authors: Conte Antonella , Bettolo Chiara Marini , Onesti Emanuela , Frasca Vittorio , Iacovelli Elisa , Gilio Francesca , Giacomelli Elena , Gabriele Maria , Aragona Massimiliano , Tomassini Valentina , Pantano Patrizia , Pozzilli Carlo , Inghilleri Maurizio
Published: July 2008

Although clinical studies show that cannabinoids improve central pain in patients with multiple sclerosis (MS) neurophysiological studies are lacking to investigate whether they also suppress these patients’ electrophysiological responses to noxious stimulation. The flexion reflex (FR) in humans is a widely used technique for assessing the pain threshold and for studying spinal and supraspinal pain pathways and the neurotransmitter system involved in pain control.

In a randomized, double‐blind, placebo‐controlled, cross‐over study we investigated cannabinoid‐induced changes in RIII reflex variables (threshold, latency and area) in a group of 18 patients with secondary progressive MS. To investigate whether cannabinoids act indirectly on the nociceptive reflex by modulating lower motoneuron excitability we also evaluated the H‐reflex size after tibial nerve stimulation and calculated the H wave/M wave (H/M) ratio. Of the 18 patients recruited and randomized 17 completed the study. After patients used a commercial delta‐9‐tetrahydrocannabinol (THC) and cannabidiol mixture as an oromucosal spray the RIII reflex threshold increased and RIII reflex area decreased. The visual analogue scale score for pain also decreased, though not significantly. Conversely, the H/M ratio measured before patients received cannabinoids remained unchanged after therapy.

In conclusion, the cannabinoid‐induced changes in the RIII reflex threshold and area in patients with MS provide objective neurophysiological evidence that cannabinoids modulate the nociceptive system in patients with MS.
Efficacy and tolerance of metronidazole and miconazole nitrate in treatment of vaginitis
Authors: Peixoto Fabio , Camargos Aroldo , Duarte Geraldo , Linhares Iara , Bahamondes Luis , Petracco Alvaro
Published: July 2008

Objective

To evaluate the efficacy and tolerability of a vaginal pessary containing 750 mg of metronidazole and 200 mg of miconazole nitrate used daily for 7 days in the treatment of vaginitis.

Methods

Ninety‐two women with vaginitis participated in this phase 3 study using one vaginal pessary daily for 7 days. Gynecological and microbiological evaluations were carried out prior to and following treatment.

Results

Reductions occurred in symptoms and signs of vaginitis. Clinical cure rate was 87.7%, while the cure rates according to microscopy and Candida albicans culture were 81.8% and 73.9%, respectively. The cure rate for bacterial vaginosis was 75% and culture of Gardnerella vaginalis turned negative in 63.6% of cases following treatment. The medication was well tolerated.

Conclusion

Use of a combination of 750 mg of metronidazole and 200 mg of miconazole in a single daily application was found to be effective in the treatment of the most common causes of vaginitis.
Evaluating progress of labor in nulliparas and multiparas using the modified WHO partograph
Authors: Orji Ernest
Published: July 2008

Objective

To evaluate the progress of labor in nulliparas and multiparas using the modified World Health Organization (WHO) partograph.

Method

In a prospective study 259 nulliparas and 204 multiparas were compared for rates of normal labor progression in the active phase; of cervical dilatation plots crossing the alert line of the partograph; and of plots reaching or crossing the action line. Outcome measures were total duration of labor, mode of delivery, incidence of labor augmentation, and number of vaginal examinations.

Results

Labor duration was similar in the 2 groups and cervical dilatation remained normal for most women. In both groups, the incidence of spontaneous vaginal delivery was highest among women with normal labor progress and the incidence of both labor augmentation and operative intervention increased when labor progress was delayed.

Conclusion

Labor progress and duration were found similar for nulliparas and multiparas when monitored with the modified WHO partograph. Delay in labor progress increased the need for operative intervention and adversely affected fetal outcome.
Glucose lowering effects of inhaled insulin in healthy cats
Authors: DeClue Amy E. , Leverenz Elizabeth F. , Wiedmeyer Charles E. , Bryan Margaret E. , Reinero Carol R.
Published: July 2008

Inhaled medications have proven effective and well tolerated in cats, and inhaled insulin has been used successfully for the management of diabetes mellitus in humans. Thus, we hypothesize that delivery of aerosolized regular insulin can lower blood glucose in healthy cats. Five adult cats were administered aerosolized 0.9% saline (IS), regular insulin intravenously (IV) 0.5 U/kg, and aerosolized regular insulin 15 U/kg (I15) and 25 U/kg (I25) and blood glucose was evaluated. Mean blood glucose was significantly lower at 15, 30 and 45 min in the I25 and IV groups compared to baseline. Similarly, the IV and I25 groups had a significantly greater maximal percent change in blood glucose than the IS group. Significantly more cats developed severe hypoglycemia (<50 mg/dl; 2.7 mmol/l) in the IV and I25 groups than in the IS group. Results of this study demonstrate that aerosolized insulin can effectively lower blood glucose concentrations in healthy cats.
Migration patterns of Neolithic settlements on the abandoned Yellow and Yangtze River deltas of China
Authors: Chen Zhongyuan , Zong Yongqiang , Wang Zhanghua , Wang Hui , Chen Jing
Published: July 2008

Archaeological records of the Neolithic settlements on the eastern China coast between 35°N and 30°N, an area covering the abandoned Yellow River and the Yangtze River delta plains, reveal that Neolithic people moved from the Yellow River basin onto the northern coast for fishing, hunting and dry-land agriculture ~ 7000 yr ago. Marine transgression interrupted their activities on the low-lying (2–5 m in elevation) coastal wetlands between 6000 and 5000 yr ago, after which they reclaimed their land near the river mouths. Their migration routes on the southern Yangtze delta plain indicate another scenario: early Neolithic communities moved onto the plain for wet-rice cultivation. Despite relative sea-level rise from 7000 to 4000 yr ago, a large number of settlements were established on the lowlands between the eastern Chenier Ridges and the western Taihu Lake depression. The Chenier Ridges, with ~ 1.0 m higher topography than the adjacent coastal area, played a role in sheltering the Neolithic people. Subsequently, settlements waned considerably, possibly due to further marine inundation combined with cold climate. The present study shows that migration patterns of the Neolithic settlements are closely associated with a gradually rising sea level between 7000 and 4000 yr ago.
Necessary and sufficient analytical conditions for the existence of false gauge field copies
Authors: Sant' Anna Adonai S.
Published: July 2008

Necessary and sufficient conditions for the existence of false gauge field copies by means of the Atiyah-Singer index theorem are established. Related topics are briefly discussed.
Associations between added sugars and micronutrient intakes and status: further analysis of data from the National Diet and Nutrition Survey of Young People aged 4 to 18 years
Authors: Gibson Sigrid , Boyd Alison
Published: July 2008

Added sugars are often viewed as ‘empty calories’, negatively impacting micronutrient intakes, yet reviews consider the evidence inconclusive. This study aimed to quantify associations between dietary added sugars (as a percentage of energy) and micronutrient intake and biochemical status in the National Diet and Nutrition Survey. Using data from 1688 British children aged 4–18 years who completed 7 d weighed dietary records in 1997, micronutrient intakes were examined across quintiles of added sugars. After excluding low energy reporters, mean dietary intakes of most nutrients exceeded the reference nutrient intake, except for zinc. Compared with quintile 1 (9 % added sugars), high consumers in quintile 5 (23 % added sugars) had micronutrient intakes ranging from 24 % lower to 6 % higher (mean 14 % lower). Zinc intakes in quintile 1 v. quintile 5 averaged 93 % v. 78 % of reference nutrient intake; magnesium 114 % v. 94 %; iron 115 % v. 100 %; and vitamin A 111 % v. 92 %, respectively. Plasma levels of magnesium, zinc and carotenoids did not vary across quintiles, but weak negative correlations were observed with serum ferritin and transferrin saturation. Plasma selenium was inversely correlated with added sugars (r − 0·17; P < 0·0001) but there was no association with glutathione peroxidase. The impact of added sugars on micronutrient intakes appears modest overall but may have relevance for children consuming inadequate amounts of nutrient-rich foods coupled with a diet high in added sugars (approximately 23 %). Further work is needed to explore the impact of different sources of added sugars and to refine assessments of inadequate intakes and status.
Disturbances in the spontaneous attribution of social meaning in schizophrenia
Authors: Horan W. P. , Nuechterlein K. H. , Wynn J. K. , Lee J. , Castelli F. , Green M. F.
Published: July 2008

Background

Schizophrenia patients show disturbances on a range of tasks that assess mentalizing or ‘Theory of Mind’ (ToM). However, these tasks are often developmentally inappropriate, make large demands on verbal abilities and explicit problem-solving skills, and involve after-the-fact reflection as opposed to spontaneous mentalizing.

Method

To address these limitations, 55 clinically stable schizophrenia out-patients and 44 healthy controls completed a validated Animations Task designed to assess spontaneous attributions of social meaning to ambiguous abstract visual stimuli. In this paradigm, 12 animations depict two geometric shapes ‘interacting’ with each other in three conditions: (1) ToM interactions that elicit attributions of mental states to the agents, (2) Goal-Directed (GD) interactions that elicit attributions of simple actions, and (3) Random scenes in which no interaction occurs. Verbal descriptions of each animation are rated for the degree of Intentionality attributed to the agents and for accuracy.

Results

Patients had lower Intentionality ratings than controls for ToM and GD scenes but the groups did not significantly differ for Random scenes. The descriptions of the patients less closely matched the situations intended by the developers of the task. Within the schizophrenia group, performance on the Animations Task showed minimal associations with clinical symptoms.

Conclusions

Patients demonstrated disturbances in the spontaneous attribution of mental states to abstract visual stimuli that normally evoke such attributions. Hence, in addition to previously established impairment on mentalizing tasks that require logical inferences about others' mental states, individuals with schizophrenia show disturbances in implicit aspects of mentalizing.
The Hipparcos Catalogue: 10th anniversary and its legacy
Authors: Turon C. , Arenou F.
Published: July 2008

The European Space Agency decision to include the Hipparcos satellite into its Science Programme is placed in the context of the years 1965-1980 and in the historical perspective of the progress of astrometry. The motivation and ideas which lead to the Hipparcos design are reviewed as well as its characteristics and performance. The amount and variety of applications represent an impressive evolution from the original science case and opened the way to much more ambitious further space missions, especially Gaia, based on the same basic principles. A giant step in technology led to a giant step in science. Next steps are presented at this Symposium.
Astrometric detection and characterization of brown dwarfs
Authors: Scholz R.-D. , McCaughrean M. J. , Röser S. , Schilbach E.
Published: July 2008

As a result of failed star formation, brown dwarfs (BDs) do not reach the critical mass to ignite the fusion of hydrogen in their cores. Different from their low-mass stellar brothers, the red dwarfs, BDs cool down with their lifetime to very faint magnitudes. Therefore, it was only about 10 to 20 years ago that such ultracool objects began to be detected. Accurate astrometry can be used to detect them indirectly as companions to stars by the signature of the so-called astrometric wobble. Resolved faint BD companions of nearby stars can be identified by their common proper motion (CPM). A direct astrometric detection of the hidden isolated BDs in the Solar neighborhood is possible with deep high proper motion (HPM) surveys. This technique led to the discovery of the first free-floating BD, Kelu 1, and of the nearest BD, ε Indi B. Both were meanwhile found to be binary BDs. The astrometric orbital monitoring of ε Indi Ba+Bb, for which we know an accurate distance from the Hipparcos measurement of its primary, ε Indi A, will allow the determination of individual masses of two low-mass BDs. Hundreds of BDs have been identified for the last decade. Deep optical sky survey (SDSS) and near-infrared sky surveys (DENIS, 2MASS), played a major role in the search mainly based on colours, since BDs emit most of their light at longer wavelengths. However, alternative deep optical HPM surveys based on archival photographic data are not only sensitive enough to detect some of the nearest representatives, they do also uncover many of the rare class of ultracool halo objects crossing the Solar neighborhood at large velocities. SSSPM 1444, with the extremely large proper motion of 3.5 arcsec/yr, is one of the nearest among these subdwarfs with masses at the substellar boundary. We present preliminary parallax results for this and two other ultracool subdwarfs (USDs) from the Calar Alto Omega 2000 parallax program.
Micro-arcsecond relative astrometry by ground-based and single-aperture observations
Authors: Röll T. , Seifahrt A. , Neuhäuser R.
Published: July 2008

We present an observation method to obtain a relative astrometric precision of about 100 . . . 150 μas with ground-based and single-aperture observations. By measuring the separation of double or triple stars we want to determine the astrometric signal of an unseen substellar companion as a periodic change in the separation between the stellar components. Using an adaptive optics system we correct for atmospheric turbulences and furthermore by using a narrow band filter in the near infrared we can suppress differential chromatic refraction effects. To reach a high precision we use a statistical approach. Using the new observation mode “cube-mode” (where the frames were directly saved in cubes with nearly no loss of time during the readout), we obtain several thousand frames within half an hour. After the verification of the Gaussian distributed behaviour of our measurements (done with a Kolmogorov-Smirnov-Test) the measurement precision can be calculated as the standard deviation of our measurements divided by the square root of the number of frames.

To monitor the stability of the pixel scale between our observations, we use the old globular cluster 47 Tuc as a calibration system.
Probing the properties of the Milky Way's central supermassive black hole with stellar orbits
Authors: Ghez A. M. , Salim S. , Weinberg N. , Lu J. , Do T. , Dunn J. K. , Matthews K. , Morris M. , Yelda S. , Becklin E. E.
Published: July 2008

We report new precision measurements of the properties of our Galaxy's supermassive black hole. Based on astrometric (1995-2007) and radial velocity (2000-2007) measurements from the W. M. Keck 10 meter telescopes, the Keplerian orbital parameters for the short period star S0-2 imply a distance of 8.3 ± 0.3 kpc, an enclosed mass of 4.8 ± 0.3 × 106M⊙, and a black hole position that is localized to within ± 1 mas and that is consistent with the position of SgrA*-IR. Astrometric bias from source confusion is identified as a significant source of systematic error and is accounted for in this study. Our black hole mass and distance are significantly higher than previous estimates. The higher mass estimate brings the Galaxy into better agreement with the relationship between the mass of the central black hole and the velocity dispersion of the host galaxy's bulge observed for nearby galaxies. It also raises the orbital period of the innermost stable orbit of a non-spinning black hole to 38 min and increases the Rauch-Tremaine resonant relaxation timescales for stars in the vicinity of the central black hole. Taking the black hole's distance as a measure of R0, which is a fundamental scale for our Galaxy, and other measurements of galactic constants, we infer a value of the Galaxy's local rotation speed (θ0) of 255 ± 13 km s−1. With the precisions of the astrometric and radial velocity measurements that are now possible with Laser Guide Star Adaptive Optics, we expect to be able to measure Ro to an accuracy of ~ 1% within the next ten years, which could considerably reduce the uncertainty in the cosmological distance ladder.
CCD astrometric observations of faint satellites and update of their orbits
Authors: Shen K. X. , Tang Z. H. , Qiao R. C. , Wang S. H. , Yan Y. R. , Cheng X.
Published: July 2008

This paper reports on our observing campaign of faint satellites performed at the National Time Service Center and Sheshan station of SHAO from 1994 up to today. In the past few years due to benefit from using a large size CCD and the publication of the modern catalogues (UCAC2), a series of observations of faint satellites were obtained by us. Moreover the work of improving the orbit of Phoebe via numerical fit to the observations over a century is also presented.
Antarctic Project for astrometric observations
Authors: Popescu P. P. , Paraschiv P. V. , Nedelcu D. A. , Badescu O.
Published: July 2008

Astronomical Institute of Romanian Academy initiated this project in 2005. The results of researches related to the construction of mechanic systems and the proposed astrometric tasks will be finished in 2008. The module PROTEL is a result of several research groups and it will perform astrometric control observations remotely.
The VLTI as a tool to study eclipsing binaries for an improved distance scale
Authors: Shabun K. , Richichi A. , Munari U. , Siviero A. , Paczynski† B.
Published: July 2008

Long-baseline interferometry with facilities such as the ESO VLTI is beginning to have the capability to measure directly in the range of milliarcsecond and less the angular separation and the angular diameter of some selected eclipsing binary systems. We have begun to carry out such observations with the AMBER instrument. In the special case of double-lined eclipsing binaries with well-detached components, from radial velocity and light curves it is possible to obtain a full solution of all orbital and stellar parameters, with the exception of the effective temperature of one star, which is normally estimated from spectral type or derived from atmospheric analysis of the spectrum or reddening-corrected photometric colors. In particular, we aim at deriving directly the effective temperature at least of one component in the proposed system, thereby avoiding any assumptions in the global solution through the Wilson-Devinney method. We have obtained an independent check of the results of this method concerning the distance to the system. This represents the first step toward a global calibration of eclipsing binaries as distance indicators. Our results will also contribute to the effective temperature scale for hot stars. The extension of this approach to a wider sample of eclipsing binaries could provide an independent method to assess the distance to the LMC.
Astrometry with the VLTI: calibration of the Fringe Sensor Unit for the PRIMA astrometric camera
Authors: Sahlmann J. , Abuter R. , Ménardi S. , Vasisht G.
Published: July 2008

The future PRIMA facility at the Very Large Telescope Interferometer (VLTI) in astrometric mode offers the possibility to perform relative narrow-angle astrometry with 10 micro-arcsecond accuracy. This is achieved with a dual-beam interferometer concept, where a reference star and the scientific target, confined in a 60 arcsecond field, are observed simultaneously. The angular separation of the two stellar objects gives rise to an optical delay in the interferometer, which is measured by the Fringe Sensor Unit (FSU) and an internal laser metrology. PRIMA is using two FSU fringe detectors, each observing the interference of stellar beams coming from one of the two objects and measuring the corresponding phase and group delay. The astrometric observable, yielding the angular separation, is deduced from the group delay difference observed between the two objects. In addition, the FSU phase delay estimate is used as error signal for the fringe stabilisation loop of the VLTI. Both functions of the FSU require high precision fringe phase measurements with a goal of 1 nm rms (corresponding to λ/2000). These can only be achieved by applying a calibration procedure prior to the observing run. We discuss the FSU measurement principle and the applied algorithms. The calibration strategy and the methods used to derive the calibration parameters are presented. Special attention is given to the achieved measurement linearity and repeatability. The quality of the FSU calibration is crucial in order to achieve the ultimate accuracy and to fulfill the primary objective of PRIMA astrometry: the detection and characterisation of extrasolar planetary systems.
ESPRI data-reduction strategy and error budget for PRIMA
Authors: Tubbs R. , Elias N. M. , Launhardt R. , Reffert S. , Delplancke F. , Quirrenbach A. , Henning T. , Queloz D. ,   ESPRI Consortium
Published: July 2008

The Exoplanet Search with PRIma (ESPRI) will use the PRIMA dual-feed astrometric capability on the Very Large Telescope Interferometer (VLTI) to perform astrometric detections of extra-solar planets. We present an overview of our data-reduction strategy for achieving 10-μarcsecond accuracy narrow-angle astrometry using the PRIMA instrument. We discuss the error budget for astrometric measurements, and those aspects of our strategy which are designed to minimise the astrometric measurement errors.
A method of accurate guiding for LAMOST
Authors: Yu Y. , Qi Z. X. , Mao Y. D. , Tang Z. H. , Zhao M.
Published: July 2008

The main optical instruments of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) are installed separately. Guiding is realized by adjusting the normal direction of the mirror MA. In order to keep the central star imaged on the rotation center of the fiber plug plate, the link between celestial and fiber plug plate coordinate systems has to be established. Some local parameters contain errors so that the normal direction of the MA calculated beforehand may not be accurate enough. The execution error of the telescope also drives the image of the central star to deviate from the rotation center. Therefore, in the process of observations the correction has to be calculated and applied periodically. Here we present the method of calculating the guiding parameters as well as the correction parameters for the LAMOST.
Micro-arcsecond astrometry with the VLBA
Authors: Reid M. J.
Published: July 2008

The VLBA is now achieving parallaxes and proper motions with accuracies approaching the micro-arcsecond domain. The apparent proper motion of Sgr A*, which reflects the orbit of the Sun around the Galactic center, has been measured with high accuracy. This measurement strongly constrains Θ0/R0 and offers a dynamical definition of the Galactic plane with Sgr A*at its origin. The intrinsic motion of Sgr A*is very small and comparable to that expected for a supermassive black hole. Trigonometric parallaxes and proper motions for a number of massive star forming regions (MSFRs) have now been measured. For almost all cases, kinematic distances exceed the true distances, suggesting that the Galactic parameters, R0 and Θ0, are inaccurate. Solutions for the Solar Motion are in general agreement with those obtained from Hipparcos data, except that MSFRs appear to be rotating slower than the Galaxy. Finally, the VLBA has been used to measure extragalactic proper motions and to map masers in distant AGN accretion disks, which will yield direct estimates of H0.
The Square Kilometre Array
Authors: Taylor A. R.
Published: July 2008

The SKA is a global project to plan and construct the next-generation international radio telescope operating at metre to cm wavelengths. More than 50 institutes in 19 countries are involved in its development. The SKA will be an interferometric array with a collecting area of up to one million square metres and maximum baseline of at least 3000 km. The SKA reference design includes field-of-view expansion technology that will allow instantaneous imaging of up to several tens of degrees. The SKA is being designed to address fundamental questions in cosmology, physics and astronomy. The key science goals range from the epoch or re-ionization, dark energy, the formation and evolution of galaxies and large-scale structure, the origin and evolution of cosmic magnetism, strong-field tests of gravity and gravity wave detection, the cradle of life, and the search for extraterrestrial intelligence. The sensitivity, field-of-view and angular resolution of the SKA will make possible a program to create a multi-epoch data base of wide-angle relative astrometry to a few μas precision for ~10,000,000 radio sources with S > 10 μJy.
The FAST telescope and its possible contribution to high precision astrometry
Authors: Jin C. J. , Nan R. D. , Gan H. Q.
Published: July 2008

In this report we give a brief introduction to the Five hundred meter Apeture Spherical Telescope (FAST). Some possible contributions of FAST to high precision astrometry are discussed. The illuminated aperture of FAST in normal operation mode is 300m in diameter. With special feeding mechanism, the whole 500m aperture could be used. FAST will cover frequencies from 70MHz to 3GHz, and observe at zenith angle of up to 40 degrees without a notable gain loss. As the most sensitive single dish radio telescope, FAST would be able to discover more mega-masers and measure the radial velocities of masers with higher precision. This may yield more delicate dynamics of their maser spots. FAST will increase the precision of time of arrival (ToA) measurements for pulsars. This will help in detecting the stochastic gravitational wave background and in establishing an independent timing standard based on the long-term stability of the rotations of a group of millisecond pulsars. FAST might also work as a very powerful ground station for the future space missions. In a three-way communication mode, FAST should be able to provide precise ranging and Doppler measurements. Moreover, by joining the international VLBI network, FAST would help to improve the precision of the VLBI astrometry measurements.
Monitoring the lunar capture of Chang'E-1 satellite by real-time reduction of the instantaneous state vectors
Authors: Guo L. , Li J. L. , Qiao S. B. , Tian F.
Published: July 2008

Based on our independently developed data processing software, the real-time reduction of the instantaneous state vectors of satellite during the maneuver stage near to perilune is analyzed via experimental observations. Results show that it is a quick and practical method to monitor the orbit evolution and the lunar capture of Chang'E-1 satellite.
Distance and kinematics of IRAS 19134+2131 revealed by H2O maser observations
Authors: Imai H. , Sahai R. , Morris M.
Published: July 2008

Using the VLBA, we have observed H2O maser emission in the pre-planetary nebula, IRAS 19134+2131 (I1913), in which the H2O maser spectrum has two groups of emission features separated in radial velocity by ~100 km s−1. The morphology and 3-D kinematics indicate the existence of a fast collimated flow with a dynamical age of only ~40 years. Such a “water fountain” source is a signature of the recent operation of a stellar jet, that may be responsible for the final shape of the planetary nebula into which I1913 is expected to evolve. We have also estimated the distance to I1913 (~8 kpc) on the basis of an annual parallax and the kinematics of IRAS 19134+2131 in our Galaxy. I1913 may be a component in the “thick disk” or the Galactic “warp”, whose kinematics is different from that of the Galactic “thin” disk. These results are reported in Imai, Sahai & Morris (2007).
Parallax measurement of the Galactic Mira variables with VERA
Authors: Nakagawa A. , Omodaka T. , Shibata K. M. , Kurayama T. , Imai H. , Kameno S. , Tsushima M. , Matsumoto N. , Matsui M. ,   VERA project team
Published: July 2008

Parallax measurements of the Galactic Mira variables with VERA have started since 2004 to establish their Period-Luminosity (PL) relationship in the Galaxy. Multi-epoch VLBI observations of a semiregular variable S Crt yielded an accurate parallax of 2.27±0.14 mas corresponding to the distance of 441+29−24 pc. In addition to the distance, we obtained physical properties of S Crt. Temperature of the photosphere was found to be ~3000 K by fitting the infrared spectrum with a blackbody radiation. The stellar radius was obtained based on the distance, apparent magnitude, and the temperature. Internal proper motions of circularly-arranged maser spots in S Crt were detected for the first time. Observations of the other Mira variables, such as R UMa, SY Scl, AP Lyn, and WX Psc are in progress.
Tropospheric correction in VLBI phase-referencing using GPS data
Authors: Zhang B. , Zheng X. W. , Li J. L. , Xu Y. , Wu J. F.
Published: July 2008

Comparing the tropospheric zenith delays derived from VLBI and GPS data at VLBA stations collocated with GPS antenna, the systematic biases and standard deviations of the difference are both found to be at the level of a sub-centimeter. Based on this agreement, we used GPS data to correct the tropospheric effects in VLBI phase-referencing, resulting in close peak-to-noise ratios of images after tropospheric correction using GPS and VLBI data.
Infrared space astrometry project JASMINE
Authors: Gouda N. , Kobayashi Y. , Yamada Y. , Yano T. ,   JASMINE Working Group
Published: July 2008

A Japanese plan of an infrared (z-band:0.9 μas or k-band:2.2 μas) space astrometry (JASMINE-project) is introduced. JASMINE (Japan Astrometry Satellite Mission for INfrared Exploration) will measure distances and tangential motions of stars in the bulge of the Milky Way. It will measure parallaxes, positions with an accuracy of 10 μas and proper motions with an accuracy of 10 μas/year for stars brighter than z=14 mag or k=11 mag. JASMINE will observe about ten million stars belonging to the bulge component of our Galaxy. With a completely new “map” of the Galactic bulge, it is expected that many new exciting scientific results will be obtained in various fields of astronomy. Presently, JASMINE is in a development phase, with a targeted launch date around 2016. Science targets, preliminary design of instruments, observing strategy, critical technical issues in JASMINE and also Nano-JASMINE project are described in this paper.
A Gaia oriented analysis of a large sample of quasars
Authors: Andrei A. H. , Assafin M. , Barache C. , Bouquillon S. , Bourda G. , Camargo J. I. B. , le Campion J.-F. , Charlot P. , Gontier A.-M. , Lambert S. , Osório J. J. Pereira , da Silva Neto D. N. , Souchay J. , Martins R. Vieira
Published: July 2008

Gaia photometric capabilities should distinguish quasars to a high degree of certainty. With this, they should also be able to deliver a clean sample of quasars with a negligible trace of stellar contaminants. However, a purely photometric sample could miss a non negligible percentage of ICRF sources counterparts - and this interface is required to align with the ICRS and de-rotate the GCRF (Gaia Celestial Reference Frame), on grounds of continuity. To prepare a minimum clean sample forming the initial quasar catalogue for the Gaia mission, an all sky ensemble was formed containing 128,257 candidates. Among them there is at least one redshift determination for 98.75%, and at least one magnitude determination for 99.20% of the targets. The sources were collected from different optical and radio lists. We analyze the redshift, magnitude, and color distributions, their relationships, as well as their degree of completeness.

Complementary, the candidate sources enable to form an optical representation of the ICRS from first principles, namely, kinematically non-rotating with respect to the ensemble of distant extragalactic objects, aligned to the mean equator and dynamical equinox of J2000, and realized by a list of adopted coordinates of extragalactic sources.
Gaia Science Operations Centre
Authors: O'Mullane W. , Lammers U. , Hoar J. , Hernandez J.
Published: July 2008

The Gaia Science Operations Centre (SOC), based at ESAC near Madrid, is building up to play an important role in Gaia operations and data processing.
Gaia Data Flow System (GDFS) Project: the UK's contribution to Gaia data processing
Authors: Walton N. A. , Cropper M. , Gilmore G. , Irwin M. , van Leeuwen F.
Published: July 2008

Gaia is an ESA cornerstone mission which will observe some billion stars in the galaxy enabling micro-arcsec astrometric catalogues to be constructed. In addition Gaia will produce high quality photometric and spectroscopic catalogues.

The data processing tasks are large and complex. A European consortium has been formed - the Gaia Data Processing and Analysis Consortium (DPAC). This paper describes the form of the UK Gaia Data Flow System Project contribution to the DPAC.
Maintenance and densification: current proper-motion catalogs
Authors: Girard T. M.
Published: July 2008

An overview of currently available, large-area, proper-motion catalogs is presented. These include the well-known catalogs based on historical Schmidt-telescope surveys as well as other projects that make use of observational material the primary purpose of which, from inception, was the determination of proper motions. The various catalogs are characterized and compared, with an emphasis on their limitations and their appropriateness for various astrophysical uses.

In addition to allowing for the maintenance of a practical celestial reference system, absolute proper-motion surveys provide the raw material from which a better understanding of our Galaxy's structure and kinematics can be built. Several examples will be cited in which large proper-motion surveys are used to probe and describe the distinct stellar components that comprise our Milky Way Galaxy.
The GSC-II catalog release GSC 2.3: description and properties
Authors: Bucciarelli B. , Lattanzi M. G. , McLean B. , Drimmel R. , Greene G. , Loomis C. , Morbidelli R. , Pannunzio R. , Smart R. L. , Spagna A.
Published: July 2008

The GSC 2.3 is a current catalog release extracted from the Guide Star Catalog II database, which is maintained at the Space Telescope Science Institute in Baltimore, USA. The catalog contains astrometry, multi-band photometry (BJ,RJ,IN) and star/non-star classification for 945,592,683 objects down to the magnitude limit of the survey plates. We review the performance of stellar parameters, anticipating the improvements in astrometric accuracy foreseen by its recalibration with the newly available catalog in the UCAC series.
CTIO 0.9m observations of ICRF optical counterparts
Authors: Zacharias M. I. , Zacharias N.
Published: July 2008

We present astrometric results from 7 observing runs at the Cerro Tololo Interamerican Observatory (CTIO) 0.9m telescope of 197 extragalactic reference frame sources, selected from the original International Celestial Reference Frame (ICRF) catalog. This is part of the U.S. Naval Observatory (USNO) reference frame link program. Contemporaneous to the CTIO deep imaging, wide-field CCD data were taken with the USNO Twin Astrograph to provide accurate secondary reference stars in the 13 to 16 mag range. The optical positions are on the Hipparcos system (via Tycho-2 stars). The unweighted, mean RMS of positional differences ‘optical–radio’ for a single source is 28 and 25 mas for RA and Dec, respectively.
Source structure: an essential piece of information for generating the next ICRF
Authors: Charlot P. , Fey A. L. , Collioud A. , Ojha R. , Boboltz D. A. , Camargo J. I. B.
Published: July 2008

The intrinsic radio structure of the extragalactic sources is one of the limiting factors in defining the International Celestial Reference Frame (ICRF). This paper reports about the ongoing work to monitor the structural evolution of the ICRF sources by using the Very Long Baseline Array and other VLBI telescopes around the world. Based on more than 5000 VLBI images produced from such observations, we have assessed the astrometric suitability of 80% of the ICRF sources. The number of VLBI images for a given source varies from 1 for the least-observed sources to more than 20 for the intensively-observed sources. Overall, we identify a subset of 194 sources that are highly compact at any of the available epochs and which are prime candidates for the realization of the next ICRF with the highest accuracy.
Relativistic astrometry and astrometric relativity
Authors: Klioner S. A.
Published: July 2008

The interplay between modern astrometry and gravitational physics is very important for the progress in both these fields. Below some threshold of accuracy, Newtonian physics fails to describe observational data and the Einstein's relativity theory must be used to model the data adequately. Many high-accuracy astronomical techniques have already passed this threshold. Moreover, modern astronomical observations cannot be adequately modeled if relativistic effects are considered as small corrections to Newtonian models. The whole way of thinking must be made compatible with relativity: this starts with the concepts of time, space and reference systems.

An overview of the standard general-relativistic framework for modeling of high-accuracy astronomical observations is given. Using this framework one can construct a standard set of building blocks for relativistic models. A suitable combination of these building blocks can be used to formulate a model for any given type of astronomical observations. As an example the problem of four dimensional solar system ephemerides is exposed in more detail. The limits of the present relativistic formulation are also briefly summarized.

On the other hand, high-accuracy astronomical observations play important role for gravitational physics itself, providing the latter with crucial observational tests. Perspectives for these astronomical tests for the next 15 years are summarized.
Definition and realization of the celestial intermediate reference system
Authors: Capitaine N.
Published: July 2008

The 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

General 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

In 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

The 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

We 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

We 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

As 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

The 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

We 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.