scholarly journals Einstein’s accelerated reference systems and Fermi–Walker coordinates

2018 ◽  
Vol 96 (10) ◽  
pp. 1085-1091 ◽  
Author(s):  
Josep Llosa

We show that the uniformly accelerated reference systems proposed by Einstein when introducing acceleration in the theory of relativity are what is known at present as Fermi–Walker coordinate systems. We then consider more general accelerated motions and, on the one hand we obtain Thomas precession and, on the other, we prove that the only accelerated reference systems that at any time admit an instantaneously comoving inertial system belong necessarily to the Fermi–Walker class.

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


Author(s):  
Brian Bayly

The suggestion in view is that when volume is lost by diffusive mass transfer, the consequent shortening rate along some direction n is controlled by ∇2σnn regardless of the spatial variations in other stress components. The nature of the argument advanced is comparable with the one on which the theory of relativity is based: “At two separate points in a universe, it is not reasonable to suppose that the fundamental laws of behavior will be different at one point from the other.” If it is only in respect to some reference frame set up by an observer that point P differs from point Q, one should not expect behavior at P to differ from behavior at Q. It is convenient to use anthropomorphic phrasing: “If there is nothing intrinsic about point P to tell the material there to behave differently, the material at P will behave in the same way as the material at Q.” The theme of this chapter is that the material process for diffusive mass transfer is almost indistinguishable from the process for volume-conserving viscous change of shape at a point. In fact it will be argued that the two processes are so similar that it is not reasonable to suppose that behavior will be governed by different laws in the two modes: only an observer can distinguish one process from the other. Again anthropomorphically, “The moving material itself has no means of knowing which process it is involved in. Hence, if it is direction-dependent quantities such as σnn that control behavior in change of shape at a point, it must also be direction-dependent quantities such as σnn that control diffusive mass transfer.” In presenting the argument, it is convenient to imagine an atomic material for purposes of example, and for the sake of concreteness; but it is emphasized at the outset that the atoms are of minimal significance—the objective is a theory for a continuum. We wish to treat a continuum in which diffusion occurs, and even a continuum with only one component in which self-diffusion occurs, and most people find that this requires imagining division of the continuum into particles on some scale: but we need this division only in the most abstract sense, just enough to permit the idea that the continuum is self-diffusive.


Author(s):  
A. G. Walker

Relativity is the study of matter in motion, and the basis of a theory of relativity can be either physical, mathematical, or logical. It is physical if some of the elementary objects and relations are concepts derived from the external world and if certain of their properties are assumed as physically obvious. If, however, the elementary objects, etc. are defined as mathematical symbols and relations, and if the subsequent theorems are mathematical deductions from these definitions, then the theory may be described as mathematical. Lastly, the basis of a theory is logical if certain terms are undefined—and clearly stated as such—and if the theory is then developed strictly deductively from an explicit set of axioms and definitions. Analogous examples taken from geometry are the Euclidean, algebraic, and projective theories. The first, as developed by Euclid, has a physical basis, while the second is mathematical, a point being defined as an ordered set of numbers (co-ordinates) and a line as the class of points satisfying a linear equation. The third is logical, the undefined elements being point and line (an undefined class of points) and the axioms being those of incidence, extension, etc. Usually a physical theory comes first, to be followed by a mathematical and then by a logical theory, this last being so constructed that it includes previous theories when its undefined elements are replaced on the one hand by the conceptual physical objects and on the other hand by the symbolic mathematical objects. The construction of such a logical theory is not merely a matter of academic interest, for it can be regarded as an analysis of the previous theories. It tests, for example, the consistency and independence of their basic assumptions and definitions. It also indicates how a theory can be modified, with as little change as possible, so as to include some feature previously excluded. This can be particularly useful in the case of a physical theory which has been constructed to correspond as closely as possible to the external world, for such a theory may need continual modification to keep in step with observational data. For this reason the axioms of a logical theory should be not only consistent and independent but also simple, i.e. indivisible.


Gesnerus ◽  
2009 ◽  
Vol 66 (1) ◽  
pp. 15-39
Author(s):  
Jakob Tanner

Far from being merely a medium of simplification and conveyance of scientific facts, motion pictures exhibit an important epistemic function. On the one hand, the medium film is itself a product of research in various fields, on the other hand, it retroacts on perception and problem-solving in science, thereby influencing and changing research practices. The paper aims at describing these reciprocal effects and synergies by discussing two examples: first by the film “The principles of Einstein’s theory of relativity”, first released in Germany in 1922, second by the film “Mathematical image of the struggle for life”, produced in 1937 for the inauguration of the “Palace of discoveries” in Paris, demonstrating the latest developments in evolutionary theory. It becomes evident that picture media have the capacity to transform the symbolic dimension of things and bodies, thereby offering new access to reality, which not only fascinated the spectators, but also inspired scientific research.


Metaphysics ◽  
2020 ◽  
pp. 69-81
Author(s):  
I. A Babenko ◽  
Yu. S Vladimirov

The article compares the descriptions of gravitational and electromagnetic interactions in two physical and theoretical paradigms: geometric and relational. On the one hand, the general theory of relativity and the 5-dimensional geometric theory of Kaluza and, on the other hand, the relational theory of electro-gravity are compared. The comparison describes the parallel manifestations of all the “four miracles” of Salam in two physical and theoretical approaches. Based on the relational concepts, it is shown that three types of the considered interactions - electromagnetic, scalar and gravitational - in the theory of electrogravity have a derivative character from electromagnetism. The idea is expressed that in the twentieth century, physics could develop mainly within the framework of the relational paradigm.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2005 ◽  
Vol 44 (03) ◽  
pp. 107-117
Author(s):  
R. G. Meyer ◽  
W. Herr ◽  
A. Helisch ◽  
P. Bartenstein ◽  
I. Buchmann

SummaryThe prognosis of patients with acute myeloid leukaemia (AML) has improved considerably by introduction of aggressive consolidation chemotherapy and haematopoietic stem cell transplantation (SCT). Nevertheless, only 20-30% of patients with AML achieve long-term diseasefree survival after SCT. The most common cause of treatment failure is relapse. Additionally, mortality rates are significantly increased by therapy-related causes such as toxicity of chemotherapy and complications of SCT. Including radioimmunotherapies in the treatment of AML and myelodyplastic syndrome (MDS) allows for the achievement of a pronounced antileukaemic effect for the reduction of relapse rates on the one hand. On the other hand, no increase of acute toxicity and later complications should be induced. These effects are important for the primary reduction of tumour cells as well as for the myeloablative conditioning before SCT.This paper provides a systematic and critical review of the currently used radionuclides and immunoconjugates for the treatment of AML and MDS and summarizes the literature on primary tumour cell reductive radioimmunotherapies on the one hand and conditioning radioimmunotherapies before SCT on the other hand.


2017 ◽  
Vol 47 (188) ◽  
pp. 487-494
Author(s):  
Daniel Mullis

In recent years, political and social conditions have changed dramatically. Many analyses help to capture these dynamics. However, they produce political pessimism: on the one hand there is the image of regression and on the other, a direct link is made between socio-economic decline and the rise of the far-right. To counter these aspects, this article argues that current political events are to be understood less as ‘regression’ but rather as a moment of movement and the return of deep political struggles. Referring to Jacques Ranciere’s political thought, the current conditions can be captured as the ‘end of post-democracy’. This approach changes the perspective on current social dynamics in a productive way. It allows for an emphasis on movement and the recognition of the windows of opportunity for emancipatory struggles.


1996 ◽  
pp. 13-23
Author(s):  
Mykhailo Babiy

Political ideological pluralism, religious diversity are characteristic features of modern Ukrainian society. On the one hand, multiculturalism, socio-political, religious differentiation of the latter appear as important characteristics of its democracy, as a practical expression of freedom, on the other - as a factor that led to the deconsocialization of society, gave rise to "nodal points" of tension, confrontational processes, in particular, in political and religious spheres.


2003 ◽  
pp. 15-26
Author(s):  
P. Wynarczyk
Keyword(s):  
The Core ◽  

Two aspects of Schumpeter' legacy are analyzed in the article. On the one hand, he can be viewed as the custodian of the neoclassical harvest supplementing to its stock of inherited knowledge. On the other hand, the innovative character of his works is emphasized that allows to consider him a proponent of hetherodoxy. It is stressed that Schumpeter's revolutionary challenge can lead to radical changes in modern economics.


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