General Relativistic Geodetic Spin Precession in Binary Pulsar B1913+16: Mapping the Emission Beam in Two Dimensions

AbstractRelativistic spin-orbit coupling should cause the spin axis of Binary Pulsar B1913+16 to precess at a rate of about 1 deg / yr. As a result, the pulse profile is expected to exhibit secular evolution. Weisberg, Romani, & Taylor (1989), and Weisberg & Taylor (1992) found that the intensity ratio of the two conal components changed at a one percent per year rate from 1981 to 1989, but that their spacing did not measurably change. They attributed these observations to our line of sight passing across the middle of a patchy cone of emission. Recently Kramer (1998) found that the intensity ratio continued its secular change for another decade, and also detected a narrowing of the conal component separation.We present our analysis of eighteen years of 21 cm pulse profile data. We confirm that the profile is narrowing as precession finally carries our line of sight away from the emission beam axis, and we map the beam in two dimensions. The beam is elongated in the latitude direction, and the degree of elongation grows with radius.

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NADA-FLD: a general relativistic, multidimensional neutrino-hydrodynamics code employing flux-limited diffusion

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2791 ◽

2019 ◽

Vol 490 (3) ◽

pp. 3545-3572 ◽

Cited By ~ 5

Author(s):

N Rahman ◽

O Just ◽

H-T Janka

Keyword(s):

Operator Splitting ◽

Lateral Diffusion ◽

Neutrino Energy ◽

Two Dimensions ◽

Polar Coordinates ◽

General Relativistic ◽

Energy Dependent ◽

Main Effects ◽

Limited Diffusion ◽

Good Agreement

ABSTRACT We present the new code NADA-FLD to solve multidimensional neutrino-hydrodynamics in full general relativity (GR) in spherical polar coordinates. The energy-dependent neutrino transport assumes the flux-limited diffusion approximation and evolves the neutrino energy densities measured in the frame comoving with the fluid. Operator splitting is used to avoid multidimensional coupling of grid cells in implicit integration steps involving matrix inversions. Terms describing lateral diffusion and advection are integrated explicitly using the Allen–Cheng or the Runge–Kutta–Legendre method, which remain stable even in the optically thin regime. We discuss several toy-model problems in one and two dimensions to test the basic functionality and individual components of the transport scheme. We also perform fully dynamic core-collapse supernova (CCSN) simulations in spherical symmetry. For a Newtonian model, we find good agreement with the M1 code ALCAR, and for a GR model, we reproduce the main effects of GR in CCSNe already found by previous works.

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Measurements of general relativistic effects in the binary pulsar PSR1913 + 16

Nature ◽

10.1038/277437a0 ◽

1979 ◽

Vol 277 (5696) ◽

pp. 437-440 ◽

Cited By ~ 257

Author(s):

J. H. Taylor ◽

L. A. Fowler ◽

P. M. McCulloch

Keyword(s):

Relativistic Effects ◽

Binary Pulsar ◽

General Relativistic

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Evidence for geodetic spin precession in the binary pulsar 1913 + 16

The Astrophysical Journal ◽

10.1086/168193 ◽

1989 ◽

Vol 347 ◽

pp. 1030 ◽

Cited By ~ 83

Author(s):

J. M. Weisberg ◽

R. W. Romani ◽

J. H. Taylor

Keyword(s):

Spin Precession ◽

Binary Pulsar

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Is There Still Something Left That Gravity Probe B Can Measure?

Universe ◽

10.3390/universe6060085 ◽

2020 ◽

Vol 6 (6) ◽

pp. 85

Author(s):

Lorenzo Iorio

Keyword(s):

Equations Of Motion ◽

Parallel Transport ◽

Analytical Calculation ◽

Spin Precession ◽

Gravity Probe B ◽

Orbital Phase ◽

Orbital Configuration ◽

General Relativistic ◽

Gravity Probe ◽

Mass Quadrupole

We perform a full analytical and numerical treatment, to the first post-Newtonian (1pN) order, of the general relativistic long-term spin precession of an orbiting gyroscope due to the mass quadrupole moment J 2 of its primary without any restriction on either the gyro’s orbital configuration and the orientation in space of the symmetry axis k ^ of the central body. We apply our results to the past spaceborne Gravity Probe B (GP-B) mission by finding a secular rate of its spin’s declination δ which may be as large as ≲30–40 milliarcseconds per year mas yr − 1 , depending on the initial orbital phase f 0 . Both our analytical calculation and our simultaneous integration of the equations for the parallel transport of the spin 4-vector S and of the geodesic equations of motion of the gyroscope confirm such a finding. For GP-B, the reported mean error in measuring the spin’s declination rate amounts to σ δ ˙ GP − B = 18.3 mas yr − 1 . We also calculate the general analytical expressions of the gravitomagnetic spin precession induced by the primary’s angular momentum J . In view of their generality, our results can be extended also to other astronomical and astrophysical scenarios of interest like, e.g., stars orbiting galactic supermassive black holes, exoplanets close to their parent stars, tight binaries hosting compact stellar corpses.

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The tangled web of agency

Behavioral and Brain Sciences ◽

10.1017/s0140525x17001170 ◽

2018 ◽

Vol 41 ◽

Author(s):

Alain Pe-Curto ◽

Julien A. Deonna ◽

David Sander

Keyword(s):

Two Dimensions ◽

Bad Company

AbstractWe characterize Doris's anti-reflectivist, collaborativist, valuational theory along two dimensions. The first dimension is socialentanglement, according to which cognition, agency, and selves are socially embedded. The second dimension isdisentanglement, the valuational element of the theory that licenses the anchoring of agency and responsibility in distinct actors. We then present an issue for the account: theproblem of bad company.

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A transmission electron microscopic study of structural transitions in fast ionic conductors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125713 ◽

1987 ◽

Vol 45 ◽

pp. 156-157

Author(s):

R. B. Queenan ◽

P. K. Davies

Keyword(s):

Optical Properties ◽

Ionic Conduction ◽

Recent Observation ◽

Ionic Conductivities ◽

Sodium Aluminate ◽

Two Dimensions ◽

Ionic Conductors ◽

Electron Microscopic ◽

Transmission Electron ◽

Trivalent Cations

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.

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Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158376 ◽

1990 ◽

Vol 48 (3) ◽

pp. 166-167

Author(s):

J. Holy ◽

G. Schatten

Keyword(s):

Confocal Microscopy ◽

Mitotic Spindle ◽

Laser Scanning ◽

Three Dimensional ◽

Laser Scanning Confocal Microscopy ◽

Two Dimensions ◽

Embryonic Cells ◽

Mitotic Spindles ◽

Cleavage Division ◽

Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

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Instrumental and Ideological Union Commitment: Longitudinal Assessment of Construct Validity

European Journal of Psychological Assessment ◽

10.1027//1015-5759.17.2.98 ◽

2001 ◽

Vol 17 (2) ◽

pp. 98-111 ◽

Cited By ~ 1

Author(s):

Anders Sjöberg ◽

Magnus Sverke

Keyword(s):

Construct Validity ◽

Temporal Stability ◽

Strong Support ◽

Internal Consistency Reliability ◽

Measurement Model ◽

Two Dimensions ◽

Model Parameters ◽

Longitudinal Assessment ◽

Union Commitment ◽

Union Participation

Summary: Previous research has identified instrumentality and ideology as important aspects of member attachment to labor unions. The present study evaluated the construct validity of a scale designed to reflect the two dimensions of instrumental and ideological union commitment using a sample of 1170 Swedish blue-collar union members. Longitudinal data were used to test seven propositions referring to the dimensionality, internal consistency reliability, and temporal stability of the scale as well as postulated group differences in union participation to which the scale should be sensitive. Support for the hypothesized factor structure of the scale and for adequate reliabilities of the dimensions was obtained and was also replicated 18 months later. Tests for equality of measurement model parameters and test-retest correlations indicated support for the temporal stability of the scale. In addition, the results were consistent with most of the predicted differences between groups characterized by different patterns of change/stability in union participation status. The study provides strong support for the construct validity of the scale and indicates that it can be used in future theory testing on instrumental and ideological union commitment.

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The Prediction of Problem-Solving Assessed Via Microworlds

European Journal of Psychological Assessment ◽

10.1027/1015-5759/a000263 ◽

2016 ◽

Vol 32 (4) ◽

pp. 298-306 ◽

Cited By ~ 7

Author(s):

Samuel Greiff ◽

Katarina Krkovic ◽

Jarkko Hautamäki

Keyword(s):

Working Memory ◽

Problem Solving ◽

Complex Problem ◽

Two Dimensions ◽

Assessment Instruments ◽

Complex Problem Solving ◽

Visual Spatial ◽

Rule Knowledge ◽

Rule Application ◽

Fluid Reasoning

Abstract. In this study, we explored the network of relations between fluid reasoning, working memory, and the two dimensions of complex problem solving, rule knowledge and rule application. In doing so, we replicated the recent study by Bühner, Kröner, and Ziegler (2008) and the structural relations investigated therein [ Bühner, Kröner, & Ziegler, (2008) . Working memory, visual-spatial intelligence and their relationship to problem-solving. Intelligence, 36, 672–680]. However, in the present study, we used different assessment instruments by employing assessments of figural, numerical, and verbal fluid reasoning, an assessment of numerical working memory, and a complex problem solving assessment using the MicroDYN approach. In a sample of N = 2,029 Finnish sixth-grade students of which 328 students took the numerical working memory assessment, the findings diverged substantially from the results reported by Bühner et al. Importantly, in the present study, fluid reasoning was the main source of variation for rule knowledge and rule application, and working memory contributed only a little added value. Albeit generally in line with previously conducted research on the relation between complex problem solving and other cognitive abilities, these findings directly contrast the results of Bühner et al. (2008) who reported that only working memory was a source of variation in complex problem solving, whereas fluid reasoning was not. Explanations for the different patterns of results are sought, and implications for the use of assessment instruments and for research on interindividual differences in complex problem solving are discussed.

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