scholarly journals Astronomical Constraints on Some Long-Range Models of Modified Gravity

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Lorenzo Iorio
Keyword(s):  
Long Range ◽  
Modified Gravity ◽  
The Other ◽  
Newtonian Potential ◽  
Orbital Parameters ◽  
Curvature Invariants ◽  
General Relativistic ◽  
Braneworld Model ◽  
Analytical Expressions ◽  
Working Out

We use the corrections to the Newton-Einstein secular precessions of the longitudes of the perihelia of the inner planets, phenomenologically estimated E.V. Pitjeva by fitting almost one century of data with the EPM2004 ephemerides, to constrain some long-range models of modified gravity recently put forth to address the dark energy and dark matter problems. They are the four-dimensional ones obtained with the addition of inverse powers and logarithm of some curvature invariants, and the DGP multidimensional braneworld model. After working out the analytical expressions of the secular perihelion precessions induced by the corrections to the Newtonian potential of such models, we compare them to the estimated extra-rates of perihelia by taking their ratio for different pairs of planets instead of using one perihelion at a time for each planet separately, as done so far in literature. The curvature invariants-based models are ruled out, even by rescaling by a factor 10 the errors in the estimated planetary orbital parameters. Less neat is the situation for the DGP model. Only the general relativistic Lense-Thirring effect, not included, as the other exotic models considered here, by Pitjeva in the EPM force models, passes such a test.

scholarly journals CONSTRAINING THE PREFERRED-FRAME α1, α2 PARAMETERS FROM SOLAR SYSTEM PLANETARY PRECESSIONS

2014 ◽  
Vol 23 (01) ◽  
pp. 1450006 ◽  
Author(s):  
L. IORIO
Keyword(s):  
Binary System ◽  
Solar System ◽  
Relative Motion ◽  
A Priori ◽  
The Other ◽  
Preferred Frame ◽  
General Relativistic ◽  
Ppn Parameters ◽  
Invariable Plane ◽  
Analytical Expressions

Analytical expressions for the orbital precessions affecting the relative motion of the components of a local binary system induced by Lorentz-violating Preferred Frame Effects (PFE) are explicitly computed in terms of the Parametrized Post-Newtonian (PPN) parameters α1, α2. Preliminary constraints on α1, α2 are inferred from the latest determinations of the observationally admitted ranges [Formula: see text] for any anomalous Solar System planetary perihelion precessions. Other bounds existing in the literature are critically reviewed, with particular emphasis on the constraint [Formula: see text] based on an interpretation of the current close alignment of the Sun's equator with the invariable plane of the Solar System in terms of the action of a α2-induced torque throughout the entire Solar System's existence. Taken individually, the supplementary precessions [Formula: see text] of Earth and Mercury, recently determined with the INPOP10a ephemerides without modeling PFE, yield α1 = (0.8±4) × 10-6 and α2 = (4±6) × 10-6, respectively. A linear combination of the supplementary perihelion precessions of all the inner planets of the Solar System, able to remove the a priori bias of unmodeled/mismodeled standard effects such as the general relativistic Lense–Thirring precessions and the classical rates due to the Sun's oblateness J2, allows to infer α1 = (-1 ± 6) × 10-6, α2 = (-0.9 ± 3.5) × 10-5. Such figures are obtained by assuming that the ranges of values for the anomalous perihelion precessions are entirely due to the unmodeled effects of α1 and α2. Our bounds should be improved in the near-mid future with the MESSENGER and, especially, BepiColombo spacecrafts. Nonetheless, it is worthwhile noticing that our constraints are close to those predicted for BepiColombo in two independent studies. In further dedicated planetary analyses, PFE may be explicitly modeled to estimate α1, α2 simultaneously with the other PPN parameters as well.

scholarly journals Inverse Problem for Ising Connection Matrix with Long-Range Interaction

Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1624
Author(s):  
Leonid Litinskii ◽  
Boris Kryzhanovsky
Keyword(s):  
Inverse Problem ◽  
Long Range ◽  
Random Number ◽  
Connection Matrix ◽  
Range Interaction ◽  
Connection Matrices ◽  
Ising Systems ◽  
Long Range Interaction ◽  
Matrix Spectrum ◽  
Analytical Expressions

In the present paper, we examine Ising systems on d-dimensional hypercube lattices and solve an inverse problem where we have to determine interaction constants of an Ising connection matrix when we know a spectrum of its eigenvalues. In addition, we define restrictions allowing a random number sequence to be a connection matrix spectrum. We use the previously obtained analytical expressions for the eigenvalues of Ising connection matrices accounting for an arbitrary long-range interaction and supposing periodic boundary conditions.

scholarly journals Hiketeia

1973 ◽  
Vol 93 ◽  
pp. 74-103 ◽  
Author(s):  
John Gould
Keyword(s):  
Dominant Role ◽  
Ancient Greece ◽  
Social Institutions ◽  
The Other ◽  
Sixth Century ◽  
Dead Body ◽  
Greek Literature ◽  
The World ◽  
The One ◽  
Working Out

To Professor E. R. Dodds, through his edition of Euripides'Bacchaeand again inThe Greeks and the Irrational, we owe an awareness of new possibilities in our understanding of Greek literature and of the world that produced it. No small part of that awareness was due to Professor Dodds' masterly and tactful use of comparative ethnographic material to throw light on the relation between literature and social institutions in ancient Greece. It is in the hope that something of my own debt to him may be conveyed that this paper is offered here, equally in gratitude, admiration and affection.The working out of the anger of Achilles in theIliadbegins with a great scene of divine supplication in which Thetis prevails upon Zeus to change the course of things before Troy in order to restore honour to Achilles; it ends with another, human act in which Priam supplicates Achilles to abandon his vengeful treatment of the dead body of Hector and restore it for a ransom. The first half of theOdysseyhinges about another supplication scene of crucial significance, Odysseus' supplication of Arete and Alkinoos on Scherie. Aeschylus and Euripides both wrote plays called simplySuppliants, and two cases of a breach of the rights of suppliants, the cases of the coup of Kylon and that of Pausanias, the one dating from the mid-sixth century, the other from around 470 B.C. or soon after, played a dominant role in the diplomatic propaganda of the Spartans and Athenians on the eve of the Peloponnesian War.

LONG DURATION ECHOES FROM AURORA, METEORS, AND IONOSPHERIC BACK-SCATTER

1953 ◽  
Vol 31 (2) ◽  
pp. 171-181 ◽  
Author(s):  
D. W. R. McKinley ◽  
Peter M. Millman
Keyword(s):  
Long Range ◽  
High Frequency ◽  
The Other ◽  
Very High Frequency ◽  
Long Duration ◽  
E Region ◽  
Very High ◽  
Visual Observations

In the course of the Ottawa meteor program some unusual echoes have been detected on 33 Mc. Echoes from the aurora are discussed and correlated with visual observations. Two mechanisms of radio reflections from the aurora have been proposed but the data here presented are insufficient to favor one over the other. On Aug. 4, 1948, six extremely long duration meteor echoes were observed which may have been due to abnormal ionospheric conditions. From time to time since August, 1948, a weak semipermanent echo has been recorded, usually appearing at a range of about 80 km., and enduring up to an hour. It is suggested that this echo is due to back-scatter from the same sources in the lower E-region that are presumed to be responsible for long-range very high frequency propagation.

ABSENCE OF PHASE TRANSITIONS ON TREE STRUCTURES

1993 ◽  
Vol 07 (29n30) ◽  
pp. 1947-1950 ◽  
Author(s):  
RAFFAELLA BURIONI ◽  
DAVIDE CASSI
Keyword(s):  
Long Range ◽  
Nearest Neighbor ◽  
Linear Chain ◽  
Mean Field ◽  
Range Order ◽  
The Other ◽  
Long Range Order ◽  
Field Phase ◽  
Tree Structures ◽  
Bethe Lattices

We rigorously prove that the correlation functions of any statistical model having a compact transitive symmetry group and nearest-neighbor interactions on any tree structure are equal to the corresponding ones on a linear chain. The exponential decay of the latter implies the absence of long-range order on any tree. On the other hand, for trees with exponential growth such as Bethe lattices, one can show the existence of a particular kind of mean field phase transition without long-range order.

A NATIONAL HEALTH PROGRAM: ORGANIZED DIVERSITY

PEDIATRICS ◽  
1975 ◽  
Vol 55 (6) ◽  
pp. 817-817
Author(s):  
P. Starr
Keyword(s):  
Water Supply ◽  
Medical Care ◽  
Long Range ◽  
Annual Cost ◽  
Health Program ◽  
Good Reason ◽  
Social Activity ◽  
The Other ◽  
Medical Reform ◽  
The Government

The pivotal long-range question in medical reform is whether medicine should be viewed as a technical activity with occasional moral or social overtones or, alternatively, as a social and moral activity with a technical substratum. Is . . . medical care . . .more like the supply of water or the provision of education? If medical care is ultimately a technical activity like water supply, its management can be safely entrusted to experts in the field. If, on the other hand, medical care is primarily a moral and social activity like education, the situation is quite different . . . . Consequently, in organizing our institutions, we have good reason to provide for both participation and diversity. We may also wish to sacrifice some of the "efficiency" of a single, professionally run system for the relative inefficiency of variegated institutions sometimes in conflict with one another. In the system advocated . . . the government would pay the basic annual cost, although families would choose to spend more for additional services. What I am proposing here is an organized system that uses competition in a premeditated fashion: competition under constraint.

scholarly journals Memorial Book of the Chechen Republic

2011 ◽  
pp. 58-62
Author(s):  
Zarema H. Ibragimova
Keyword(s):  
The Other ◽  
Historical Events ◽  
Documentary Sources ◽  
Great Patriotic War ◽  
History Of ◽  
Working Out

On the history of the Memorial Book of the Chechen Republic as compared with preparation and publication of similar books in the other country’s regions. Working out of historical and documentary sources and present them a wide public in the long term reconstruction of historical events of the Great Patriotic War is actual.

scholarly journals On the 2PN Periastron Precession of the Double Pulsar PSR J0737–3039A/B

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 443
Author(s):  
Lorenzo Iorio
Keyword(s):  
General Relativity ◽  
Present Author ◽  
Moment Of Inertia ◽  
The Other ◽  
Orbital Elements ◽  
Binary Pulsars ◽  
Orbital Phase ◽  
Order Of Magnitude ◽  
General Relativistic ◽  
The Moment

One of the post-Keplerian (PK) parameters determined in timing analyses of several binary pulsars is the fractional periastron advance per orbit kPK. Along with other PK parameters, it is used in testing general relativity once it is translated into the periastron precession ω˙PK. It was recently remarked that the periastron ω of PSR J0737–3039A/B may be used to measure/constrain the moment of inertia of A through the extraction of the general relativistic Lense–Thirring precession ω˙LT,A≃−0.00060∘yr−1 from the experimentally determined periastron rate ω˙obs provided that the other post-Newtonian (PN) contributions to ω˙exp can be accurately modeled. Among them, the 2PN seems to be of the same order of magnitude of ω˙LT,A. An analytical expression of the total 2PN periastron precession ω˙2PN in terms of the osculating Keplerian orbital elements, valid not only for binary pulsars, is provided, thereby elucidating the subtleties implied in correctly calculating it from k1PN+k2PN and correcting some past errors by the present author. The formula for ω˙2PN is demonstrated to be equivalent to that obtainable from k1PN+k2PN by Damour and Schäfer expressed in the Damour–Deruelle (DD) parameterization. ω˙2PN actually depends on the initial orbital phase, hidden in the DD picture, so that −0.00080∘yr−1≤ω˙2PN≤−0.00045∘yr−1. A recently released prediction of ω˙2PN for PSR J0737–3039A/B is discussed.

scholarly journals Observations on the mobilization of peat nitrogen in incubation experiments

1959 ◽  
Vol 31 (1) ◽  
pp. 268-281
Author(s):  
Jaakko Kivekäs ◽  
Erkki Kivinen
Keyword(s):  
Nitrate Nitrogen ◽  
Ammonium Nitrogen ◽  
The Other ◽  
Incubation Experiments ◽  
Different Types ◽  
Working Out ◽  
Original Amount

60 peat samples from northern Finland representing different types of peat were incubated in a laboratory at a temperature of 17—18° C. The ammonium nitrogen, the nitrate nitrogen and the pH in the samples were determined after one month of incubation as well as after three months of incubation. The results were compared to results from determinations made before incubation. An attempt was made to elucidate the factors that influence the mobilization of nitrogen. On the basis of the above results it is evident that the differences between the various peat types as mobilizers of nitrogen are under these circumstances not very distinct, nor do these differences seem to be dependent on the types of peat. The following facts can, however, be established: In the amounts of ammonium nitrogen an increase takes place in most groups of samples during the first month. This increase is fairly big in the Sphagnum-dominated peats. The increase in ammonium nitrogen continues in the unlimed samples in most peat groups during all three months of incubation. After three months of incubation the amount of ammonium nitrogen in the limed samples is smaller than in the unlimed samples, although it is usually bigger than in the original samples. After the first month of incubation the amounts of nitrate nitrogen in all types of peat have decreased compared to the amounts in the original samples. In the limed samples the decrease is not as great as in the unlimed ones. After three months of incubation the amount of nitrate nitrogen has considerably increased as compared to the amount after one month of incubation. In the limed samples it might to some extent exceed the original amount of nitrate nitrogen, however, this is seldom the case in the unlimed samples. If the results are calculated on the basis of weight unit, it can be stated that the ability to mobilize nitrogen is greater in the Sphagnum peats than in the other peat groups. Working out the results in kg per ha it will be noted that somewhat more nitrogen is mobilized in the Carex-dominated than in the Sphagnum-dominated peats. The results obtained by experiments in the laboratory are not directly applicable to conditions in the field.

Building Materials and Techniques

1997 ◽  
Author(s):  
Roger Ling ◽  
Paul Arthur ◽  
Georgia Clarke ◽  
Estelle Lazer ◽  
Lesley A. Ling ◽  
...  
Keyword(s):  
Building Materials ◽  
The Other ◽  
Upper Crust ◽  
Calcareous Tufa ◽  
Volcanic Ashes ◽  
Wear And Tear ◽  
Modern House ◽  
Working Out ◽  
Yellowish White

Much of the ensuing discussion will focus on the working-out of structural sequences, first within individual houses or parts of houses, then within the insula as a whole. As a preface to this discussion, it is necessary to give a description of the building materials and techniques found in the insula. Brief surveys of Pompeian building techniques have appeared in various publications. Still one of the most serviceable accounts is that of R. C. Carrington in his article ‘Notes on the building materials of Pompeii” published in 1933, and most of the forms of construction found in I10 are discussed therein. First, the materials. The commonest is the socalled ‘Sarno stone’ (often inaccurately called limestone’), a yellowish white calcareous tufa which is very rough and porous, being riddled with the imprints of shells and vegetable matter; it is used both in large blocks to form quoins and the like and in smaller rubble for facing and infilling of all types. Next most common is a hard grey (trachytic) lava which is stronger and more water resistant than Sarno stone but which, because it is less easy to cut into regular shapes, is generally employed in the form of small rubble. An exception to this rule is its use for door thresholds, where its hardness is well suited to withstanding wear and tear. Rather less common in our insula is the red or purple vesicular lava known as cruma (English “scoria”), derived from the frothy upper crust of consolidated lava streams; it is occasionally cut into small blocks but more normally occurs as a sporadic material in rubble wall-facings where Sarno stone and grey lava predominate. The other main lithic materials found in the insula are varieties of tufo (tuff), formed by the consolidation of volcanic ashes. The brown or grey tuff from Nuceria (modern Nocera) is a hard and close-grained material containing darker brown or blackish specks. It can be easily cut to shape when freshly exposed in the quarry but hardens later on contact with the air, so is ideally suited for producing ashlar blocks, small tufelli (blocks of similar size to modern house bricks) and the pyramidal pieces used in reticulate work (opus reticulaium: see below), not to mention carved detail such as column and pilaster capitals.

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