After Lavoisier's execution, the leading French chemists were Antoine-François Fourcroy , Louis-Bernard Guyton de Morveau and Claude-Louis Berthollet . At the beginning of the nineteenth century, Berthollet introduced a new conception of chemical change that challenged the theory of elective affinities which had dominated chemistry for nearly a hundred years. Berthollet's new affinities raised controversy among chemists and had to coexist with the firmly established theory of elective affinities. Apart from the public debate in research articles, Berthollet's affinities also had (...) to compete with the influence of Fourcroy and his school in the textbook market. This paper seeks to assess the extent to which French textbooks published at the beginning of the nineteenth century were committed to Berthollet's innovation, and how they contributed to its marginalization. (shrink)

A history of design changes for the eudiometer.

Popper conceived an experiment whose analysis led to a result that he deemed absurd. Popper wrote that his reasoning was based on the Copenhagen interpretation and therefore invalidated it. Many authors who have examined Popper's analysis have found in it various technical flaws which are briefly summarized here. However, the aim of the present article is not technical. My concern is to redress logical flaws in Popper's argument: the terminology he uses is ambiguous, his analysis involves counterfactual hypotheses, and it (...) violates Bohr's complementarity principle. Therefore, the absurdity of Popper's result only confirms Bohr's approach. (shrink)

Bell inequalities are derived for any number of observers, any number of alternative setups for each one of them and any number of distinct outcomes for each experiment. It is shown that if a physical system consists of several distant subsystems, and if the results of tests performed on the latter are determined by local variables with objective values, then the joint probabilities for triggering any given set of distant detectors are convex combinations of a finite number of Boolean arrays, (...) whose components are either 0 or 1 according to a simple rule. This convexity property is both necessary and sufficient for the existence of local objective variables. It leads to a simple graphical method which produces a large number of generalized Clauser-Horne inequalities corresponding to the faces of a convex polytope. It is plausible that quantum systems whose density matrix has a positive partial transposition satisfy all these inequalities, and therefore are compatible with local objective variables, even if their quantum properties are essentially non-local. (shrink)

The Einstein–Podolsky–Rosen paradox (1935) is reexamined in the light of Shannon’s information theory (1984). The EPR argument did not take into account that the observer’s information was localized, like any other physical object.

The proof of Bell's inequality is based on the assumption that distant observers can freely and independently choose their experiments. As Bell's inequality isexperimentally violated, it appears that distant physical systems may behave as a single, nonlocal, indivisible entity. This apparent contradiction is resolved. It is shown that the “free will” assumption is, under usual circumstances, an excellent approximation.I have set before you life and death, blessing and cursing: therefore choose life.... —Deuteronomy XXX, 19.

This paper contains four new dialogues among Simplicio, Salviati, and Sagredo, on the fate of Schrödinger's cat, the existence of physical quantities, the paradigm of Einstein, Podolsky, and Rosen, and why a watched kettle may boil, after all.

Linear combinations of “elements of reality,” as defined by Einstein, Podolsky, and Rosen, may not be themselves “elements of reality.” There are questions which can be formulated (and unambiguously answered) in the ordinary language of experimental physics, but cannot be represented in the mathematical framework of quantum theory in a nontrivial way.

L’auteur présente trois témoignages. Le premier montre l’influence que la figure de frère Charles de Jésus a exercée sur lui et sur ceux qui l’ont accompagné en pèlerinage. Le second explique pourquoi, aux yeux de l’auteur, le Père de Foucauld peut être considéré comme un martyr de la foi et de la charité. Le troisième raconte comment, mettant ses pas dans les pas de frère Charles, l’auteur a passé presque deux ans dans un ermitage, sur l’Assekrem, dans le Hoggar. C’est (...) là qu’est née l’intuition fondatrice des Fraternités Monastiques de Jérusalem. (shrink)

The city of lions. Beaulieu-sur-Dordogne. The war starts. Drôle de guerre. Going to work. Going to school. Fleeing from village to village. Playing cat and mouse. The second landing. Return to Beaulieu. Return to Paris. Joining the boyscouts. Learning languages. Israel becomes independent. Arrival in Haifa. Kalay high school. Military training. The Hebrew Technion in Haifa. Relativity. Asher Peres. Metallurgy. Return to France. Escape from jail. Aviva.I am the cat who walks by himself, and all places are alike to me.Rudyard (...) KiplingI am grateful to all those who contributed to this Festschrift which celebrates my 70th birthday and therefore the beginning of my eighth decade. In the Jewish religion, there is a prayer, “she-hehhyanu” to thank the Lord for having kept us alive and let us reach this day. I am an atheist and I have no Lord to thank, but I wish to thank many other people who are no longer alive and who helped me reach this point. (shrink)

The purpose of this paper is to review and clarify the quantum “measurement problem.” The latter originates in the ambivalent nature of the “observer”: Although the observer is not described by the Schrödinger equation, it should nevertheless be possible to “quantize” him and include him in the wave function if quantum theory is universally valid. The problem is to prove that no contradiction may arise in these two conflicting descriptions. The proof invokes the notion of irreversibility. The validity of the (...) latter is questionable, because the standard rationale for classical irreversibility, namely mixing and coarse graining, does not apply to quantum theory. There is no chaos in a closed, finite quantum system. However, when a system is large enough, it cannot be perfectly isolated from its “environment,” namely from external (or even internal) degrees of freedom which are not fully accounted for in the Hamiltonian of that system. As a consequence, the long-range evolution of such a quantum system is essentially unpredictable. It follows that the notion of irreversibility is a valid one in quantum theory and the “measurement problem” can be brought to a satisfactory solution. (shrink)

An imprecise measurement of a dynamical variable (such as a spin component) does not, in general, give the value of another dynamical variable (such as a spin component along a slightly different direction). The result of the measurement cannot be interpreted as the value of any observable that has a classical analogue.

The physicist not only observes phenomena, but he also has an active role in the formulation of some laws. For instance, laws involving irreversibility refer explicitly to what can or cannot be done by physicists. As the abilities of the latter may vary, we obtain sequences of laws, the convergence of which is discussed.

A generalized Kochen-Specker theorem is proved. It is shown that there exist sets of n projection operators, representing n yes-no questions about a quantum system, such that none of the 2″ possible answers is compatible with sum rules imposed by quantum mechanics. Namely, if a subset of commuting projection operators sums up to a matrix having only even or only odd eigenvalues, the number of “yes” answers ought to he even or odd, respectively. This requirement may lead to contradictions. An (...) example is provided, involving nine projection operators in a 4-dimensional space. (shrink)

This dialogue between Achilles and the Tortoise – in the spirit of those of Carroll and Hofstadter – argues against the idea, identified with the “traditional” interpretation of Aristotle’s “sea battle argument”, that future contingents are an exception to the Principle of Bivalence. It presents examples of correct everyday predictions, without which one would not be able to decide and to act; however, doing this is incompatible with the belief that the content of these predictions lacks a truth-value. The cost (...) of using a non-classical logic to cope with that may be too high for Stagirite’s defenders, and they would still need to explain why our ordinary predictions seem to have a binary truth-value. In the end, the paper suggests that the problem of future contingents – and of free will – is not a logical problem at all, but rather a limit on what an agent can believe before taking a decision. (shrink)

Esports have transformed playing video games into a competitive activity that bears similarities to sports and the processes of sportization. Taking as a starting point the concept of sports as competitive games, the objective of this work is to analyse the sportization of esports, as well as the impact of esports on the concept of sports and their implications on sports in the immediate future. Sports and esports are two different realities that interact with each other. This is a conceptual (...) problem for sports, and it also defines a practical challenge in the immediate future of sports. The virtual environment offers new possibilities in sports, such as broadening the possibilities of confrontation and competition development, contributing to reducing the environmental impact of certain sports, improving safety and maintaining the physical integrity of athletes, and increasing social justice and equality of chances in sports competitions. The challenge, therefore, is to try to bring esports and sports closer together, even moving toward hybrid sports, as addressed throughout this article. (shrink)

Small unmanned aerial systems (sUAS) are used more regularly and widely in disaster response. Like other personnel involved in disaster response, the sUAS pilots work for long periods, experience extreme stress and fatigue. They often arrive at the disaster fatigued (due to long drives to get there). However, unlike other personnel in this domain, there is little research on the effects of fatigue on sUAS pilots. Our experiences with a series of three real-world deployments highlight the challenges of conducting human (...) factors research during disaster response and recovery. We specifically present lessons learned from having participant researchers embedded in three disasters with the sUAS pilot teams. These lessons result in a set of feasible and non-interruptive methods and metrics for conducting human factors research during field events. Preliminary results and recommended next steps are presented. (shrink)

This paper publishes for the first time 132 conjectures by Nicolaus Heinsius on Ovid’s Metamorphoses 1‒4. The value and possible motivations of each proposal are briefly assessed.

Classical propositional logic plays a prominent role in industrial applications, and yet the complexity of this logic is presumed to be non-feasible. Tractable systems such as depth-bounded boolean logics approximate classical logic and can be seen as a model for resource-bounded agents whose reasoning style is nonetheless classical. In this paper we first study a hierarchy of tractable logics that is not defined by depth. Then we extend it into a modal logic where modalities make explicit the assumptions discharged in (...) propositional proofs, thereby expressing blueprints for proofs. A natural deduction system is provided that permits to reason about and manage such proof blueprints. (shrink)

O objetivo deste estudo foi apresentar uma revisão integrativa da literatura científica nacional sobre cuidados paliativos na assistência a portadores de doenças graves, evidenciando, principalmente, o papel das equipes multidisciplinares. Foram recuperadas, a partir de critériosde localização e se..