Le lien entre l’expérience acquise par Machiavel au service de la République florentine (1498-1512) et l’œuvre politique écrite après son éloignement forcé des affaires est explicite. Tous les commentateurs se sont attachés à déceler, dans la correspondance diplomatique et les écrits mineurs ante res perditas, les thèmes qui réapparaîtront de manière aboutie dans les textes majeurs de Machiavel. Cependant, le passage de la pratique à la « théorie » n’est pas immédiat. Le ritratto, composé d’extraits d’expérience regroupés autour d’une question (...) particulière, permet une problématisation originale de l’histoire présente et s’inscrit dans l’écart qui se creuse, tout au long de l’activité diplomatique de Machiavel, entre la politique florentine qu’il est censé servir et sa propre vision des choses. Aussi le traité du Prince se fonde-t-il, non sur une réalité brute, mais sur une expérience déjà disposée dans un certain nombre de ritratti. Un immense effort pour rationaliser la politique à partir du particulier est ainsi entrepris par Machiavel, sans pour autant sacrifier ce qui précisément déclenche cette entreprise et la rend interminable, à savoir, l’irréductibilité de la fortune. (shrink)

The fourth volume of Professor Guthrie’s History, dealing with Plato’s life and with eighteen of his dialogues, is as welcome as its three predecessors. In keeping with the nature of a history of this sort, the picture of Plato’s life and thought presented here is judicious and non-controversial in its outlines. There are many helpful references both to the ancient and to the modern literature, and a vast amount of information is transmitted with surprising painlessness. For the facts of Plato’s (...) life, Guthrie relies on the traditional sources, especially on Epistle VII, the authenticity of which he accepts. His reconstruction is, therefore, itself quite traditional; little direct attention is given to Ryle’s attempt to undermine that view. The volume covers the following dialogues, listed here in the order of their presentation: Apology, Crito, Euthyphro, Laches, Lysis, Charmides, Hippias Major, Hippias Minor, Ion, Protagoras, Meno, Euthydemus, Gorgias, Menexenus, Phaedo, Symposium, Phaedrus, and Republic. No section is devoted in this volume to the first Alcibiades; Guthrie is noncommittal on its authenticity. The Cratylus and the Timaeus are also passed over because of difficulties in dating them. Somewhat questionable is the inclusion of the Phaedrus: Guthrie argues that it belongs among the middle dialogues, mainly on account of his view that the method of collection and division does not constitute a major discontinuity in Plato’s way of doing dialectic. On the question of Plato’s development, Guthrie follows most contemporary scholars in rejecting the unitarian view, according to which Plato held the theory of Forms, essentially unrevised, throughout his life. Rather, he leans towards the idea that the theory of Forms emerged out of Socrates’ concern with definition, bloomed in the middle dialogues, and came to be more critically examined in Plato’s later works. Guthrie deals with each dialogue separately: he examines each dialogue’s date, characters, and setting, presents a useful summary, and discusses a number of philosophically interesting questions. The section devoted to the Republic is a monograph in its own right and combines summary and discussion. The great virtues of this book are its level tone, its painstaking presentation of alternative views, and its scope. Though not always conclusive in its discussions of specific philosophical issues, it is a true labor of love, and unlikely to be superceded, as a reference work, in the near future.—A.N. (shrink)

The ternary xV2O5–(40 − x)Li2O–60B2O3 glass system, where x = 1, 2, 3, 4 and 6 mol%, was prepared by normal quenching. Ultrasonic velocities and attenuation were measured at room temperature using a pulse-echo technique. Various parameters, such as elastic moduli, micro-hardness, Poisson's ratio and Debye temperature, were determined from the measured densities and velocities. The composition dependence of these parameters, in addition to the glass-transition temperature, suggested that vanadium ions were incorporated into these glasses as a network modifier, resulting (...) in the reconversion of BO4 tetrahedra to BO3 triangles by the breaking of B–O–B linkages and the formation of nonbridging oxygens (NBOs). The outcome was a reduction in network connectivity and rigidity with increasing V2O5 content. The results are explained quantitatively in terms of fractal bond connectivity, average atomic volume, network dimensionality, packing density, number of network bonds per unit volume, cross-link density and atomic ring size. The Makishima and Mackenzie model appears to be valid for the studied glasses when the fate of BO4 tetrahedra and creation of NBOs are taken into account. (shrink)

In the centennial of Ettore Majorana’s birth (1906–1938?), we re-examine some aspects of his fundamental scientific production in atomic and molecular physics, including a not well known short communication. There, Majorana critically discusses Fermi’s solution of the celebrated Thomas–Fermi equation for electron screening in atoms and positive ions. We argue that some of Majorana’s seminal contributions in molecular physics already prelude to the idea of exchange interactions (or Heisenberg–Majorana forces) in his later works on theoretical nuclear physics. In all his (...) papers, he tended to emphasize the symmetries at the basis of a physical problem, as well as the limitations, rather than the advantages, of the approximations of the method employed. (shrink)

In a number of membrane-bound viruses, ion channels are formed by integral membrane proteins. These channel proteins include M2 from influenza A, NB from influenza B, and, possibly, Vpu from HIV-1. M2 is important in facilitating uncoating of the influenza A viral genome and is the target of amantadine, an anti-influenza drug. The biological roles of NB and Vpu are less certain. In all cases, the protein contains a single transmembrane α-helix close to its N-terminus. Channels can be formed by (...) homo-oligomerization of these proteins, yielding bundles of transmembrane helices that span the membrane and surround a central ion-permeable pore. Molecular modeling may be used to integrate and interpret available experimental data concerning the structure of such transmembrane pores. This has proved successful for the M2 channel domain, where two independently derived models are in agreement with one another, and with solid-state nuclear magnetic resonance (NMR) data. Simulations based on channel models may yield insights into possible ion conduction and selectivity mechanisms. BioEssays 20:992–1000, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

In a number of membrane-bound viruses, ion channels are formed by integral membrane proteins. These channel proteins include M2 from influenza A, NB from influenza B, and, possibly, Vpu from HIV-1. M2 is important in facilitating uncoating of the influenza A viral genome and is the target of amantadine, an anti-influenza drug. The biological roles of NB and Vpu are less certain. In all cases, the protein contains a single transmembrane α-helix close to its N-terminus. Channels can be formed by (...) homo-oligomerization of these proteins, yielding bundles of transmembrane helices that span the membrane and surround a central ion-permeable pore. Molecular modeling may be used to integrate and interpret available experimental data concerning the structure of such transmembrane pores. This has proved successful for the M2 channel domain, where two independently derived models are in agreement with one another, and with solid-state nuclear magnetic resonance (NMR) data. Simulations based on channel models may yield insights into possible ion conduction and selectivity mechanisms. BioEssays 20:992–1000, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

The second of these lines seems to be the result of an interpolation designed to spell out the implicit sense of the first. In 241–6 Ion has expressed amazement that Creusa should be weeping at the sight of Apollo's sanctuary, a sight which brings other visitors joy. She prefaces her explanation of this with an assurance which in its transmitted form is elegantly translated by Grégoire: ‘Il n'est point discourtois de ta part, étranger, de marquer ta surprise au sujet de (...) mes pleurs.’ But there are reasons for doubting I the authenticity of line 248: Line 247 is self-sufficient, as is shown by IA 1402: τ μν σόν, νενι, γενναίως χει. This also gives the closest parallel for the use of τ σόν in reference to the attitude which a previous speaker's words have just expressed. Other instances of τ σόν, tout court, are helpfully grouped in Allen and Italie's Concordance to Euripides, s.v. σός. τ σόν…[adverbial phrase] χει occurs also in Hek. 1195 and Med. 312; cf. HF 165, Hel. 893, Pho. 995 with τομόν. These make it unlikely that τ χόν in our passage is to be taken adverbially, as perhaps Grégoire intended with ‘de ta part’, rather than as subject of χει. Tro. 82 might be adduced for the alternative , but there is no reason for Creusa to be saying emphatically ‘as far as you are concerned’. (shrink)

This book shows how the study of multi-hadron production phenomena in the years after the founding of CERN culminated in Hagedorn's pioneering idea of limiting temperature, leading on to the discovery of the quark-gluon plasma -- announced, in February 2000 at CERN. Following the foreword by Herwig Schopper -- the Director General (1981-1988) of CERN at the key historical juncture -- the first part is a tribute to Rolf Hagedorn (1919-2003) and includes contributions by contemporary friends and colleagues, and those (...) who were most touched by Hagedorn: Tamás Biró, Igor Dremin, Torleif Ericson, Marek Gaździcki, Mark Gorenstein, Hans Gutbrod, Maurice Jacob, István Montvay, Berndt Müller, Grazyna Odyniec, Emanuele Quercigh, Krzysztof Redlich, Helmut Satz, Luigi Sertorio, Ludwik Turko, and Gabriele Veneziano. The second and third parts retrace 20 years of developments that after discovery of the Hagedorn temperature in 1964 led to its recognition as the melting point of hadrons into boiling quarks, and to the rise of the experimental relativistic heavy ion collision program. These parts contain previously unpublished material authored by Hagedorn and Rafelski: conference retrospectives, research notes, workshop reports, in some instances abbreviated to avoid duplication of material, and rounded off with the editor's explanatory notes. About the editor: Johann Rafelski is a theoretical physicist working at The University of Arizona in Tucson, USA. Born in 1950 in Krakow, Poland, he received his Ph.D. with Walter Greiner in Frankfurt, Germany in 1973. Rafelski arrived at CERN in 1977, where in a joint effort with Hagedorn he contributed greatly to the establishment of the relativistic heavy ion collision, and quark-gluon plasma research fields. Moving on, with stops in Frankfurt and Cape Town, to Arizona, he invented and developed the strangeness quark flavor as the signature of quark-gluon plasma. (shrink)