Arbitrary Interpretations Research Articles

The Dust Environment of Comet 46P/Wirtanen at Perihelion: A Period of Decreasing Activity?

The inverse dust tail model (M. Fulle 1989, Astron. Astrophys. 217, 283–297) is applied to a dust tail image of short-period Comet 46P/Wirtanen obtained by K. Jockers et al. (1998, Astron. Astrophys. 335, L56–L59) to provide information on the dust environment which will be probed by the ESA Rosetta space mission. The obtained results are consistent with those coming from dust coma photometry during 2 months before perihelion, so that we provide a dust environment model consistent with all available data concerning 46P/Wirtanen dust. Although the dust coma brightness was increasing up to perihelion, we show that most probably during the month preceding the comet perihelion the dust mass loss rate decreased from about 50 to 20 kg s −, for an assumed dust albedo of 4%. This is due to a probable time evolution of the dust size distribution power index γ, dropping from values close to −3 a month before perihelion, to values close to −4 at perihelion. These results point out how dangerous are arbitrary interpretations of the results of dust coma photometry, which, on the other hand, provide first-order quality constraints to test all dust environment models. These, however, remain indispensable to correctly interpret the collected data. The results of this paper are compared with those obtained by L. Colangeli et al. (1998, Icarus 134, 35–46) applying the same tail model to ISOCAM data, so that we obtain an upper limit of the dust albedo equal to 4% and we provide parametric expressions of the time evolution of the dust ejection velocity, mass loss rate, and size distribution over all the comet orbit section relevant for the Rosetta mission (i.e., from 2.5 to 1.0 AU inward). These expressions closely agree with those derived by M. Fulle et al. (1997a, Astron. Astrophys. Suppl. Ser. 126, 183–195) from the results of hydrodynamical models of the 46P/Wirtanen coma (J. F. Crifo and A. V. Rodionov 1997, Icarus 127, 319–353), but the perihelion decrease of the mass loss rate.

Stress and emotionality: a multidimensional and genetic approach

RAMOS, A. AND P. MORMÈDE. Stress and emotionality: A multidimensional and genetic approach. NEUROSCI BIOBEHAV REV. 22(1) 33–57, 1998—The use of behavioural tests aiming to assess the psychological components of stress in animals has led to divergent and sometimes arbitrary interpretations of animal behaviour. This paper presents a critical evaluation of behavioural methods currently used to investigate stress and emotionality. One of its main goals is to demonstrate, through experimental evidence, that emotionality may no longer be seen as a unidimensional construct. Accordingly, following a discussion about concepts, we propose a multiple-testing approach, paralleled by factor analyses, as a tool to dissociate and study the different dimensions of emotionality. Within this multidimensional context, genetic studies (illustrated here by different rat models) are shown to be particularly useful to investigate the neurobiology of stress/emotionality. A genetic approach can be used (i) to broaden and dissect the variability of responses within and between populations and (ii) to search for the molecular bases (i.e. genes and gene products) which underlie such a variability.

Reversing abstract interpretations

Program analyses are often presented as one of two brands: forwards or backwards. In this paper we explore the significance of the direction of analysis, and show how arbitrary abstract interpretations may be reversed.

Comparative metric semantics for concurrent prolog

This paper shows the equivalence of two semantics for a version of Concurrent Prolog with non-flat guards: an operational semantics based on a transition system and a denotational semantics which is a metric semantics (the domains are metric spaces). We do this in the following manner. First a uniform language L is considered, that is a language where the atomic actions have arbitrary interpretations. For this language we define an operational and a denotational semantics, and we prove that the denotational semantics is correct with respect to the operational semantics. This result relies on Banach's fixed point theorem. Techniques stemming from imperative languages are used. Then we show how to translate a Concurrent Prolog program to a program in L by selecting certain basic sets for L and then instantiating the interpretation function for the atomic actions. In this way we induce the two semantics for Concurrent Prolog and the equivalence between the two semantics.

Diderot: The Virtue of a Philosopher (review)

BOOK REVIEWS 481 Proslogion H and IlL A Third Interpretation of Anselm's Argument. By Richard R. La Croix. (Leiden: E. J. Brill, 1972. Pp. xii + 137) This modest but original little work is not another refutation or defense of the ontological argument. Such polemics presuppose that the ontological argument of Anselm has been adequately identified. The author attempts to recover Anselm's own line of thought. According to La Croix, there are three interpretations of the Proslogion. (1) The "traditional" interpretation is that Pros. II is the one argument Anselm offers for God, and that it is logically complete. (2) The "new" interpretation of Malcolm, Charlesworth, etc. holds that Pros. III contains a new argument, or at least that a new argument can be constructed from III. (3) The author's own or third interpretation, which holds that there is only one argument, constituted by the entire Proslogion, and that chapters II and III do not offer independent arguments and do not claim to prove that God exists. Although La Croix's prose is repetitive and heavy-footed, his exegesis of Anselm is very persuasive. His indicating certain propositions by arbitrary code letters, rather than writing them out, is completely unnecessary and makes impossible demands on the memory of the reader. But the content of this little book is in many respects very good and comes much closer to Anselm's own thought than many other much-touted but fundamentally arbitrary interpretations. The author's basic line, that Pros. II and III merely prove that that-than-which-no-greater-can-be-conceived exists, and that chapters V to the end show that that existing being has the attributes of God, seems altogether convincing . He concludes that Anselm's argument is formally valid. Yet in the brief evaluation of Anselm's reasoning, La Croix doubts whether the argument really proves the existence of God, since, in his view, any existential claims at all can be established merely by selecting the appropriate assumptions. In any case, the validity of his illuminating exegesis is independent of his evaluation of Anselm's argument. For those who can overlook the author's tendency to repeat himself and to labor the obvious, much can be learned from this valuable little work. The book suffers, however, from the most curious and fundamental limitations. The bibliography lists only works in English. Although half-a-dozen lines are quoted in Latin, it is obvious that the author is working from Charlesworth's translation. He has no independent grasp of the original Latin texts. He seems unfamiliar with Anselm's other works, even those which have been translated, and his exegesis of this particular argument is not supported by an understanding of Anselm's philosophy as a whole. The most valuable secondary literature on Anselm is ignored for the simple reason that it is written in French or German, which are the chief languages of research in mediaeval thought. Gilson's great article in French, perhaps the best thing ever written on the original meaning of Anselm's proof, is not mentioned in this work. So, this book is a contribution to current philosophical controversy rather than to mediaeval scholarship. PAUL I. W. MILLER University o/Colorado Diderot: The Virtue o/a Philosopher. By Carol Blum. (New York: Viking Press, 1974. Pp. viii + 182. $8.95) This relatively short book on Diderot is very well written. In fact, its style is so deceptively simple that one might be misled into believing that the work is not profound 482 HISTORY OF PHILOSOPHY or scholarly. The more closely one reads, however, it becomes quite clear that its attractive style succeeds in making a scholarly work interesting for Diderot scholars as well as for the non-specialist. As I perused this work by Professor Blum, I found myself in agreement with most of her astute and penetrating observations. I did, however, find myself frequently wondering whether on two points, one fairly important, the other minor, the author could be as dogmatic or definite as she is. The more significant matter was the degree to which Diderot was preoccupied with the importance he attached to the public's acceptance of himself as...

Theory of Superconductivity

Recently Eliashberg derived the theory of superconductivity by the Green's function technique. The energy-gap equation was deduced by a self-consistent calculation. The result is similar to the integral equation of Bardeen, Cooper, and Schrieffer except that the effective electron interaction potential is different from the Bardeen-Pines potential as well as the Bogoliubov potential. The purpose of this paper is to discuss these differences. It shows that the "dangerous terms" in the Bogoliubov theory may be calculated in a different manner. The compensation of these dangerous terms leads to the result of Eliashberg. Therefore the self-consistent calculation of Eliashberg is but a different interpretation of the Bogoliubov's idea. However, it is argued that the most reliable way of treating the problem should be the variational method because it gives the lowest ground-state energy. This method gives all the results of Bogoliubov in the lowest order of approximation, but is free from arbitrary interpretations.

A New Altimeter Display

Before commencing an analysis of the subject matter at hand, it will be as well to present some definitions which we have adopted, in our own work, even if they represent in part arbitrary interpretations of our own.(a) Pressure altitude is, of course, nothing but barometer pressure at any given elevation, converted into equivalent altitude (feet) units; hence a variable.(b) Sea-level in connection with altimetry is only a theoretical reference value which does not necessarily conform with mean-high water; in terms of pressure altitude, needless to say, it is also a variable.(c) True altitude (above sea-level) cannot be obtained with satisfactory accuracy by merely correcting for sea-level barometer pressure. On the other hand, we must dispel the notion—not uncommon—that one can obtain more accurate altitude values by correcting for temperature and humidity at a particular flight level. There are such things as inversions and convection currents; we do not need cold weather to have a high barometer, and sometimes it is warmer a few thousand feet up than at ground-level.(d) Performance of pressure instruments is properly expressed in parts of the pressure range—not in per cent of altitude—and the reason is simple: at, say, 60,000 ft. you have about 16 times as may feet per unit of pressure as at sea-level.(e) Sensitivity is—technically speaking—the smallest part of the pressure range that will produce a measurable response.