bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relativistic aspects of rotational motion of celestial bodies
Authors: Klioner S. A. , Gerlach E. , Soffel M. H. 
Published: January 2010

AbstractRelativistic modelling of rotational motion of extended bodies represents one of the most complicated problems of Applied Relativity. The relativistic reference systems of IAU (2000) give a suitable theoretical framework for such a modelling. Recent developments in the post-Newtonian theory of Earth rotation in the limit of rigidly rotating multipoles are reported below. All components of the theory are summarized and the results are demonstrated. The experience with the relativistic Earth rotation theory can be directly applied to model the rotational motion of other celestial bodies. The high-precision theories of rotation of the Moon, Mars and Mercury can be expected to be of interest in the near future.
A relativistic orbit model for the LISA mission to be used in LISA TDI simulators
Authors: Pireaux Sophie , Chauvineau Bertrand 
Published: January 2010

AbstractThe LISA mission is an interferometer, formed by three spacecraft, that aims at the detection of gravitational waves in the [10−4, 10−1] Hz frequency band. Present LISA TDI simulators, aimed at validating the novel Time Delay Interferometry method, use a classical Keplerian orbit model at first order in eccentricity in the gravitational field of a spherical non-rotating Sun, without planets. We propose to use the same model but described in the framework of relativistic gravity, and we focus here on quantifying the differences between classical and relativistic orbits for the LISA spacecraft, under the same assumptions.
The motion of vibrating systems in Schwarzchild spacetime
Authors: Hees A. , Bergamin L. , Delva P. 
Published: January 2010

AbstractIn this communication, the effects of vibrations at high frequencies onto a freely falling two-body system in Schwarzschild spacetime are investigated. We present these effects for different kinds of reference motions, all of which are placed in regions of weak gravitation: circular orbits, radial free fall (with different initial velocities) and radial free fall with a small tangential velocity. The vibrations induce a change in the motion of the vibrating system, which is characterized by a radial deviation between the vibrating system and the reference motion of the non-vibrating system. For a circular orbit, we show that the maximal radial deviation increases linearly with the initial radius. For a radial free fall, the radial deviation after one oscillation decreases quadratically with respect to the initial radius.
Gravitomagnetic effects of a massive and slowly rotating sphere with an equatorial mass current on orbiting test particles
Authors: Castañeda Leonardo , Fandiño Fernando , Almonacid William , Suárez Edilberto , Pinzón Giovanni 
Published: January 2010

AbstractWithin the framework of linearized Einstein field equations we compute the gravitomagnetic effects on a test particle orbiting a slowly rotating, spherical body with a rotating matter ring fixed to the equatorial plane. Our results show that the effect on the precession of particle orbits is increased by the presence of the ring.
Testing alternate gravitational theories
Authors: Standish E. M. 
Published: January 2010

AbstractThe planetary ephemerides are used to examine different suggested forms of the gravitational equations of motion which could possibly cause the observed Pioneer Anomaly. It is shown that most of the forms would be unacceptable, including that generally assumed – a constant acceleration directed toward the Sun. The tests show that three other forms could not exist within 10 au's of the Sun. Only one suggested form would be compatible with the Pioneer Anomaly affecting Saturn or any other more inward planet. Additional planetary observations in the future may possibly eliminate this form also.
The confrontation between general relativity and experiment
Authors: Will Clifford M. 
Published: January 2010

AbstractWe review the experimental evidence for Einstein's general relativity. A variety of high precision null experiments confirm the Einstein Equivalence Principle, which underlies the concept that gravitation is synonymous with spacetime geometry, and must be described by a metric theory. Solar system experiments that test the weak-field, post-Newtonian limit of metric theories strongly favor general relativity. Binary pulsars test gravitational-wave damping and aspects of strong-field general relativity. During the coming decades, tests of general relativity in new regimes may be possible. Laser interferometric gravitational-wave observatories on Earth and in space may provide new tests via precise measurements of the properties of gravitational waves. Future efforts using X-ray, infrared, gamma-ray and gravitational-wave astronomy may one day test general relativity in the strong-field regime near black holes and neutron stars.
APOLLO: A new push in solar-system tests of gravity
Authors: Murphy T. W. , Adelberger E. G. , Battat J. B. R. , Hoyle C. D. , McMillan R. J. , Michelsen E. L. , Stubbs C. W. , Swanson H. E. 
Published: January 2010

AbstractLunar laser ranging (LLR) has long provided many of our best measurements on the fundamental nature of gravity, including the strong equivalence principle, time -rate-of-change of the gravitational constant, the inverse square law, geodetic precession, and gravitomagnetism. This paper serves as a brief overview of APOLLO: a recently operational LLR experiment capable of millimeter-level range precision.
Tests of relativistic gravity from space
Authors: Turyshev Slava G. 
Published: January 2010

AbstractRecent experiments have successfully tested Einstein's general theory of relativity to remarkable precision. We discuss recent progress in the tests of relativistic gravity in the solar system and present motivations for the new generation of high-accuracy gravitational experiments. We especially focus on the concepts aiming to probe parameterized-post-Newtonian parameter γ and evaluate the discovery potential of the recently proposed experiments.
Black holes in active galactic nuclei
Authors: Valtonen M. J. , Mikkola S. , Merritt D. , Gopakumar A. , Lehto H. J. , Hyvönen T. , Rampadarath H. , Saunders R. , Basta M. , Hudec R. 
Published: January 2010

AbstractSupermassive black holes are common in centers of galaxies. Among the active galaxies, quasars are the most extreme, and their black hole masses range as high as to 6⋅1010M⊙. Binary black holes are of special interest but so far OJ287 is the only confirmed case with known orbital elements. In OJ287, the binary nature is confirmed by periodic radiation pulses. The period is twelve years with two pulses per period. The last four pulses have been correctly predicted with the accuracy of few weeks, the latest in 2007 with the accuracy of one day. This accuracy is high enough that one may test the higher order terms in the Post Newtonian approximation to General Relativity. The precession rate per period is 39°.1 ± 0°.1, by far the largest rate in any known binary, and the (1.83 ± 0.01)⋅1010M⊙primary is among the dozen biggest black holes known. We will discuss the various Post Newtonian terms and their effect on the orbit solution. The over 100 year data base of optical variations in OJ287 puts limits on these terms and thus tests the ability of Einstein's General Relativity to describe, for the first time, dynamic binary black hole spacetime in the strong field regime. The quadrupole-moment contributions to the equations of motion allows us to constrain the ‘no-hair’ parameter to be 1.0 ± 0.3 which supports the black hole no-hair theorem within the achievable precision.
Spatial correlations in the Gaia astrometric solution
Authors: Holl Berry , Hobbs David , Lindegren Lennart 
Published: January 2010

AbstractAccurate characterization of the astrometric errors in the forthcoming Gaia catalogue is essential for making optimal use of the data. Using small-scale numerical simulations of the astrometric solution, we investigate the expected spatial correlation between the astrometric errors of stars as function of their angular separation. Extrapolating to the full-scale solution for the final Gaia catalogue, we find that the expected correlations are generally very small, but could reach some fraction of a percent for angular separations smaller than about one degree. The spatial correlation length is related to the size of the field of view of Gaia, while the maximum correlation coefficient is related to the mean number of stars present in the field at any time. Our scalable simulation tool (AGISLab) makes it possible to characterize the astrometric errors and correlations, e.g., as functions of position and magnitude.
Gaia and the asteroids: Local test of GR
Authors: Hestroffer Daniel , Mouret S. , Mignard F. , Tanga P. , Berthier J. 
Published: January 2010

AbstractWe present in the following some capabilities of the Gaia mission for performing local test of General Relativity (GR) based on the astrometry of asteroids. This ESA cornerstone mission, to be launched in Spring 2012, will observe—in addition to the stars and QSOs—a large number of small solar system bodies with unprecedented photometric and, mostly, astrometric precisions. Indeed, it is expected that about 250,000 asteroids will be observed with a nominal precision ranging from a few milli-arcsecond (mas), to sub-mas precision, depending on the target's brightness. While the majority of this sample is constituted of known main-belt asteroids orbiting between Mars and Jupiter, a substantial fraction will be made of near-Earth objects, and possibly some newly discovered inner-Earth or co-orbital objects.Here we show the results obtained from a simulation of Gaia observations for local tests of GR in the gravitational field of the Sun. The simulation takes into account the time sequences and geometry of the observations that are particular to Gaia observations of solar system objects, as well as the instrument sensitivity and photon noise. We show the results from a variance analysis for the nominal precision of the joint determination of the solar quadrupoleJ2and the PPN parameter β. Additionally we include the link of the dynamical reference frame to the conventional kinematically non-rotating reference frame (as obtained in the visible wavelength by Gaia observations of QSOs). The study is completed by the determination of a possible variation of the gravitational constant/G, and deviation from Newtonian 1/r2gravitational law. Comparisons to the results obtained from other techniques are also given.
Toward inertial reference frames with the SIM observatory
Authors: Makarov Valeri V. 
Published: January 2010

AbstractThe SIM Lite Observatory is expected to provide a global astrometric reference frame surpassing the 1-μas accuracy threshold in some spherical harmonics. A range of time-varying physical distortions of the reference frame will become observable as large-scale perturbations of the proper motion field. I consider the main sources of the apparent and physical motion of reference objects, such as the aberration of light caused by the acceleration of SIM, long gravitational waves and hypothetical rotation of the Universe, and present some estimates of the astrometric sensitivity to these effects. I argue that a global solution and covariance analysis is of crucial importance for the SIM mission to differentiate the inevitable accidental and systematic zonal errors from real physical phenomena.
Relativistic models for the BepiColombo radioscience experiment
Authors: Milani Andrea , Tommei Giacomo , Vokrouhlický David , Latorre Emanuele , Cicalò Stefano 
Published: January 2010

AbstractTo test General Relativity with the tracking data of the BepiColombo Mercury orbiter we need relativistic models for the orbits of Mercury and of the Earth, for the light-time and for all the spatio-temporal reference frames involved, with accuracy corresponding to the measurements: ≃10 cm in range, ≃2 micron/s in range-rate, over 2 years.For the dynamics we start from the Lagrangian post-Newtonian (PN) formulation, using a relativistic equation for the solar system barycenter to avoid rank deficiency. In the determination of the PN parameters, the difficulty in disentangling the effects of β from the ones of the Sun's oblateness is confirmed. We have found a consistent formulation for the preferred frame effects, although the center of mass is not an integral. For the identification of strong equivalence principle (SEP) violations we use a formulation containing both direct and indirect effects (through the modified position of the Sun in a barycentric frame).In the light-time equations, the Shapiro effect is modeled to PN order 1 but with an order 2 correction compatible with (Moyer 2003). The 1.5-PN order corrections containing the Sun's velocity are not relevant at the required level of accuracy.To model the orbit of the probe, we use a mercury-centric reference frame with its own “Mercury Dynamic Time”: this is the largest and the only relativistic correction required, taking into account the major uncertainties introduced by non-gravitational perturbations.A delicate issue is the compatibility of our solution with the ephemerides for the other planets, and for the Moon, which cannot be improved by the BepiColombo data alone. Conversely, we plan to later export the BepiColombo measurements, as normal points, to contribute with their unprecedented accuracy to the global improvement of the planetary ephemerides.
Radio astronomy in the future: impact on relativity
Authors: Kramer Michael 
Published: January 2010

AbstractRadio astronomy has played an important part in the study of relativity. Famous examples include the discovery and exploitation of pulsars for precise binary pulsar tests, the proof of the existence of gravitational radiation and the discovery of the Cosmic Microwave background. In the future, radio astronomy will continue to play a decisive role, assisted by new and upcoming instruments like LOFAR and the SKA. In this review, I will present the revolution that is ongoing in radio astronomical techniques and outline the impact expected on the studies of relativity.
A racial comparison of Family Group Decision Making in the USA1
Authors: McCrae Julie S. , Fusco Rachel A. 
Published: January 2010

ABSTRACTThis study examined Family Group Decision Making (FGDM) among a nationally representative sample of African‐American and White children investigated for maltreatment in the US. While FGDM was developed for work with ethnic minority families, there is no research on how this is being carried out in the US, where African‐American children are overrepresented in child welfare services. The study views racial differences in child, caregiver and maltreatment characteristics related to FGDM; composition of FGDM meetings; service referrals and receipt; and service satisfaction. Data are from the National Survey of Child and Adolescent Well‐being (NSCAW), a study of 5501 children ages 0–14. Current analyses include African‐American and White children (n= 4129). Stratified, bivariate and multivariate regression analyses were used. Results showed that while race was not related FGDM receipt, different characteristics lead to FGDM among African‐American and White families. Surprisingly, caregivers report feeling no more involved in decision‐making in association with FGDM. FGDM is provided at low rates overall (10%) and less frequently among White caseworkers. Child access to mental health services increases in relation to FGDM. Implications are discussed.
Epitope shift of proteinase-3 anti-neutrophil cytoplasmic antibodies in patients with small vessel vasculitis
Authors: Selga D , Segelmark M , Gunnarsson L , Hellmark T 
Published: January 2010

SummaryAnti-neutrophil cytoplasmic antibodies against proteinase 3 (PR3-ANCA) are used as diagnostic tools for patients with small vessel vasculitis (AASV). We have produced chimeric mouse/human PR3 molecules and investigate changes in reactivity over time and the possible relationship between epitope specificity and clinical course. Thirty-eight PR3-ANCA-positive patients diagnosed between 1990 and 2003 were followed until December 2005. Plasma was collected at each out-patient visit and older samples were retrieved retrospectively. Patients reacted with multiple epitopes at the time of diagnosis. At subsequent relapses 12 patients shifted reactivity, in 11 cases from epitopes located in the C-terminal towards epitopes in the N-terminal. Patients with reactivity against N-terminal parts of PR3 at diagnosis had a significantly lower relapse rate, 30% compared to 78% in the group with predominantly C-terminal reactivity (P = 0·04). The reactivity pattern did not correlate to outcome measured as death, end-stage renal disease or vasculitis activity index score (VDI) at 5 years. Further research is necessary to conclude if this is a general phenomenon.
Microstructure investigations of dental composite samples prepared by focused ion beam technique
Authors: ANDRZEJCZUK M. , SIEJKA‐KULCZYK J. , LEWANDOWSKA M. , KURZYDŁOWSKI K.J. 
Published: January 2010

SummaryIn this study, microstructures of dental composites were observed using high resolution scanning transmission electron microscopy (HR STEM). Samples for these observations were prepared by focused ion beam system. Two kinds of dental composites were investigated: (1) polymer‐ceramic composite containing nano‐sized ceramic fillers and (2) ceramic‐polymer composite based on the nano‐structured yttrium stabilized zirconia. The first composite is a popular material for dental fillings whereas the second is used for the fabrication of fixed partial dentures. The results are discussed in terms of the evaluation of fabrication process of the composites.
Studies of aluminium coatings deposited by vacuum evaporation and magnetron sputtering
Authors: GARBACZ H. , WIECIŃSKI P. , ADAMCZYK‐CIEŚLAK B. , MIZERA J. , KURZYDŁOWSKI K.J. 
Published: January 2010

SummaryThe paper presents the results of investigations of the microstructures and properties of the aluminium coatings deposited by vacuum evaporation and magnetron sputtering. These coatings generally have a very refined microstructure with elongated nano‐grains. However, the surface topography of the aluminium coating deposited by vacuum evaporation is more developed, its microstructure is less homogeneous and more porous. The residual tensile stresses in the aluminium coating deposited by magnetron sputtering are close to 130 MPa, and the texture is relatively pronounced. Vacuum evaporation does not induce residual stresses in the coatings and the texture is very weak. The results obtained indicate that the aluminium coatings produced by magnetron sputtering are more suitable for the diffusive Ti‐Al intermetallic layers.
Microstructure and mechanical properties of Nb15Al10Ti alloy produced by mechanical alloying and high temperature processing
Authors: ROZMUS M. , BLICHARSKI M. , DYMEK S. 
Published: January 2010

SummaryIn this work, an Nb15Al10Ti alloy produced by mechanical alloying was investigated. The milling of elemental powders of Nb, Al as well as TiAl intermetallic phase resulted in the formation of homogenous niobium solid solution, Nbss, and refinement of powder particles. Powder after milling was consolidated by conventional hot pressing at 1300°C under pressure of 25 MPa as well as by hot isostatic pressing at 1200°C under pressure of 1 GPa. Microstructure of consolidated material was examined by transmission electron microscopy, scanning electron microscopy and X‐ray diffraction. Materials after consolidation were composed of three phases: niobium solid solution Nbss, Nb3Al intermetallic phase and titanium oxide dispersoid TiO. The analysis of the mechanical properties indicated that both refinement of microstructure as well as introduction of ductile Nbss into the microstructure contributed to very high yield strength and fracture toughness satisfactory for this strength.
Co‐occurring diagnoses among FMR1 premutation allele carriers
Authors: Hunter JE , Rohr JK , Sherman SL 
Published: January 2010

Hunter JE, Rohr JK, Sherman SL. Co‐occurring diagnoses among FMR1 premutation allele carriers.Following the discovery of two disorders associated with premutation alleles of the fragile X mental retardation gene (FMR1), primary ovarian insufficiency [fragile X‐associated primary ovarian insufficiency (FXPOI)] and a tremor/ataxia syndrome [fragile X‐associated tremor/ataxia disorder (FXTAS)], numerous studies have examined other potential co‐morbid conditions, including neuropsychological deficits. Here, the frequency of self‐reported diagnoses obtained through medical history interviews from FMR1 premutation carriers and non‐carriers aged 18–50 were analyzed. Study subjects included 537 women, 334 of whom carry the premutation and 151 men, 37 of whom carry the premutation. Men with the premutation did not report any medical conditions at higher rates compared with non‐carriers, controlling for age, ethnicity/race, and household income. Women with the premutation reported mental health disorders [i.e. attention deficit hyperactivity disorder (ADHD), anxiety, depression] significantly more often than non‐carriers. However, after adjusting for covariates, these increased rates were not statistically significant. Additional follow‐up analyses examined the consequence of ovarian dysfunction as a cause of co‐occurring conditions. Women with an indication of ovarian insufficiency (i.e. irregular cycles) reported higher rates of thyroid problems and depression/anxiety. Because only women, not men, reported these conditions more often, the relationship between FXPOI and hormone irregularities in women should be explored for a potential link with the increase in the reported medical conditions.
Hepatic effects of an open lung strategy and cardiac output restoration in an experimental lung injury
Authors: KREDEL M. , MUELLENBACH R. M. , HORNUNG A. , SCHMIDT R. , LAQUA J. , BREDERLAU J. , ROEWER N. , WUNDER C. 
Published: January 2010

Background: Ventilation with high positive end‐expiratory pressure (PEEP) can lead to liver dysfunction. We hypothesized that an open lung concept (OLC) using high PEEP impairs liver function and integrity dependent on the stabilization of cardiac output.Methods: Juvenile female Pietrain pigs instrumented with flow probes around the common hepatic artery and portal vein, pulmonary and hepatic vein catheters underwent a lavage‐induced lung injury. Ventilation was continued with a conventional approach (CON) using pre‐defined combinations of PEEP and inspiratory oxygen fraction or with an OLC using PEEP set above the lower inflection point of the lung. Volume replacement with colloids was guided to maintain cardiac output in the CON(V+) and OLC(V+) groups or acceptable blood pressure and heart rate in the OLC(V−) group. Indocyanine green plasma disappearance rate (ICG‐PDR), blood gases, liver‐specific serum enzymes, bilirubin, hyaluronic acid and lactate were tested. Finally, liver tissue was examined for neutrophil accumulation, TUNEL staining, caspase‐3 activity and heat shock protein 70 mRNA expression.Results: Hepatic venous oxygen saturation was reduced to 18 ± 16% in the OLC(V−) group, while portal venous blood flow decreased by 45%. ICG‐PDR was not reduced and serum enzymes, bilirubin and lactate were not elevated. Liver cell apoptosis was negligible. Liver sinusoids in the OLC(V+) and OLC(V−) groups showed about two‐ and fourfold more granulocytes than the CON(V+) group. Heat shock protein 70 tended to be higher in the OLC(V−) group.Conclusions: Open lung ventilation elicited neutrophil infiltration, but no liver dysfunction even without the stabilization of cardiac output.