Definition and Practical Realization of the Reference Frame in the Fk5 — the Role of Planetary Dynamics and Stellar Kinematics in the Definition

AbstractThe formulation of the fundamental reference system to be represented by the FK5 includes the determination of the equinox and equator on the basis of planetary dynamics and the application of the new expressions for the general precession in longitude adopted in the IAU (1976) System of Astronomical Constants. The role of hypotheses which entered the determination of the lunisolar precession is explained. Results are presented for the equinox and equator of the FK5 which are based on observations of the Sun, planets, and lunar occultations.

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Włoska Partia Socjalistyczna i opozycja zza „żelaznej kurtyny”: przypadek Polski w kontekście relacji Craxi–Solidarność

Annales Universitatis Paedagogicae Cracoviensis. Studia Politologica ◽

10.24917/20813333.25.1 ◽

2021 ◽

Vol 25 (325) ◽

pp. 5-53

Author(s):

Enrico Landoni

Keyword(s):

Turning Point ◽

Prime Minister ◽

Charismatic Leadership ◽

Practical Realization ◽

Soviet System ◽

History Of ◽

General Secretary

The election of Bettino Craxi as PSI general secretary marked, from 1976, a very important turning point in thehistory of Italian socialism. His dynamic and charismatic leadership in fact contributed to a profound revisionof its ideological seeds, the so-called scientific Marxism, and above all to the recovery of the humanitarianand libertarian suggestions of pre-Marxist socialism. This led to the clear and definitive condemnation of theMarxist-Leninist model, which had found its practical realization in the Soviet system and in the countriesbeyond the Curtain, and prompted PSI to support the anti-communist dissidence and to establish strongrelations with the Polish opposition and above all with Solidarność. Craxi, both in the role of PSI generalsecretary and as Italian prime minister, was able to provide it with a great political-diplomatic support and alot of concrete help. Up to now, the history of these relations has not yet been adequately studied and thispaper therefore aims to fill the gap.

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The “twin paradox”: the role of acceleration

Canadian Journal of Physics ◽

10.1139/cjp-2018-0788 ◽

2019 ◽

Vol 97 (10) ◽

pp. 1049-1063

Author(s):

J. Gamboa ◽

F. Mendez ◽

M.B. Paranjape ◽

Benoit Sirois

Keyword(s):

Reference Frame ◽

Relative Motion ◽

Complete Resolution ◽

Proper Time ◽

The Other ◽

Twin Paradox ◽

Age Difference ◽

Inertial Reference Frame

The “twin paradox” corresponds to the situation where two twins begin at rest in an inertial reference frame, one of them takes a journey, normally very fast and to a distant place, and then returns to the twin at rest. The “twin paradox” evokes the idea that each twin would say that it should be the other who is younger because of their relative motion. A complete resolution of the paradox corresponds to the calculation of the elapsed proper time of each twin, by each twin, and the subsequent observation that they actually get the same answer, that the travelling twin is indeedthe younger twin. Acceleration has a role to play; indeed, if one tries to calculate the age difference from the point of the view of the travelling twin, then the role of the acceleration is crucial and cannot be dismissed. In this tutorial, we show in complete and pedagogical detail, how to do the necessary calculations according to each twin using simple transformations of coordinates.

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Response Demands and Blindfolding in the Crossed-Hands Deficit: An Exploration of Reference Frame Conflict

Multisensory Research ◽

10.1163/22134808-00002423 ◽

2013 ◽

Vol 26 (5) ◽

pp. 465-482 ◽

Cited By ~ 12

Author(s):

Michelle L. Cadieux ◽

David I. Shore

Keyword(s):

Reference Frame ◽

Visual Information ◽

Reference Frames ◽

Internal Reference ◽

Eyes Closed ◽

External Reference ◽

Eyes Open ◽

Temporal Order Judgments ◽

Visual Conditions

Performance on tactile temporal order judgments (TOJs) is impaired when the hands are crossed over the midline. The cause of this effect appears to be tied to the use of an external reference frame, most likely based on visual information. We measured the effect of degrading the external reference frame on the crossed-hand deficit through restriction of visual information across three experiments. Experiments 1 and 2 examined three visual conditions (eyes open–lights on, eyes open–lights off, and eyes closed–lights off) while manipulating response demands; no effect of visual condition was seen. In Experiment 3, response demands were altered to be maximally connected to the internal reference frame and only two visual conditions were tested: eyes open–lights on, eyes closed–lights off. Blindfolded participants had a reduced crossed-hands deficit. Results are discussed in terms of the time needed to recode stimuli from an internal to an external reference frame and the role of conflict between these two reference frames in causing this effect.

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Selective role of lingual/parahippocampal gyrus and retrosplenial complex in spatial memory across viewpoint changes relative to the environmental reference frame

Behavioural Brain Research ◽

10.1016/j.bbr.2012.12.031 ◽

2013 ◽

Vol 242 ◽

pp. 62-75 ◽

Cited By ~ 53

Author(s):

Valentina Sulpizio ◽

Giorgia Committeri ◽

Simon Lambrey ◽

Alain Berthoz ◽

Gaspare Galati

Keyword(s):

Spatial Memory ◽

Reference Frame ◽

Parahippocampal Gyrus ◽

Environmental Reference

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The role of the poet in Plato's ideal cities of Callipolis and Magnesia

Kriterion Revista de Filosofia ◽

10.1590/s0100-512x2007000200004 ◽

2007 ◽

Vol 48 (116) ◽

pp. 329-349 ◽

Cited By ~ 1

Author(s):

Gerard Naddaf

Keyword(s):

Practical Realization ◽

The Status ◽

The Republic ◽

The Right ◽

Negative Factors ◽

The Ideal

Plato's attitude toward the poets and poetry has always been a flashpoint of debate, controversy and notoriety, but most scholars have failed to see their central role in the ideal cities of the Republic and the Laws, that is, Callipolis and Magnesia. In this paper, I argue that in neither dialogue does Plato "exile" the poets, but, instead, believes they must, like all citizens, exercise the expertise proper to their profession, allowing them the right to become full-fledged participants in the productive class. Moreover, attention to certain details reveals that Plato harnesses both positive and negative factors in poetry to bring his ideal cities closer to a practical realization. The status of the poet and his craft in this context has rarely to my knowledge been addressed.

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The role of visual experience in spatial reference frame preference

Seeing and Perceiving ◽

10.1163/187847612x646406 ◽

2012 ◽

Vol 25 (0) ◽

pp. 18

Author(s):

Achille Pasqualotto

Keyword(s):

Reference Frame ◽

Spatial Representation ◽

Visual Experience ◽

Reference Frames ◽

Single Point ◽

Memory Test ◽

Object Locations ◽

Congenitally Blind ◽

Spatial Reference Frame

How do people remember the location of objects? Location is always relative, and thus depends on a reference frame. There are two types of reference frames: egocentric (or observer-based) and allocentric (or environmental-based). Here we investigated the reference frame people used to remember object locations in a large room. We also examined whether the choice of a given reference frame is dictated by visual experience. Thus we tested congenitally blind, late blind, and sighted blindfolded participants. Objects were organized in a structured configuration and then explored one-by-one with participants walking back and forth from a single point. After the exploration of the locations, a spatial memory test was conducted. The memory test required participants to imagine being inside the array of objects, being oriented along a given heading, and then pointing towards the required object. Crucially the headings were either aligned to the allocentric structure of the configuration, that is rows and columns, or aligned to the egocentric route walked during the exploration of the objects. The spatial representation used by the participants can be revealed by better performance when the imagined heading in the test matches the spatial representation used. We found that participants with visual experience, that is late blind and blindfolded sighted, were better with headings aligned to the allocentric structure of the configuration. On the contrary, congenitally blind were more accurate with headings aligned to the egocentric walked routes. This suggests that visual experience during early development determines a preference for an allocentric frame of reference.

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