Theoretical reconstruction of Galileo's two-bucket experiment

In the present work, we address the solution of a problem extracted from a historical context, in which Galileo supposedly conducted an experiment to measure the percussion force of a water jet. To this end, the conservation equations of fluid mechanics in unsteady state are employed in the theoretical reconstruction of the experiment. The experimental apparatus consists of a balance, in which a counterweight hangs on to one of its extremities, and two buckets, in the same vertical, hang on to the other extremity. The water jet issuing from an orifice in the bottom of the upper bucket strikes the lower bucket. The objective is to find the jet percussion force on the lower bucket. The result of the analysis revealed that the method proposed by Galileo for the calculation of the jet percussion force is incorrect. The analysis also revealed that the resultant force during the process is practically null, which would make Galileo's account of the major movements of the balance credible, despite his having not identified all the forces acting on the system.Comment: 16 pages, 5 figure

The small and large lags of the elastic and anelastic tides. The virtual identity of two rheophysical theories

The aim of this letter is to discuss the virtual identity of two recent tidal theories: the creep tide theory of Ferraz-Mello (Cel. Mech. Dyn. Astron. 116, 109, 2013) and the Maxwell model developed by Correia et al. (Astron. Astrophys. 571, A50, 2014). It includes the discussion of the basic equations of the theories, which, in both cases, include an elastic and an anelastic component, and shows that the basic equations of the two theories are equivalent and differ by only a numerical factor in the anelastic tide. It also includes a discussion of the lags: the lag of the full tide (geodetic), dominated by the elastic component, and the phase of the anelastic tide. In rotating rocky bodies not trapped in a spin-orbit resonance (e.g., the Earth) the geodetic lag is close to zero and the phase of the semi-diurnal argument in the anelastic tide is close to 90 degrees. The results obtained from combining tidal solutions from satellite tracking data and from Topex/Poseidon satellite altimeter data, by Ray et al., are extended to determine the phase of the semi-diurnal argument in the Earth's anelastic tide as sigma_0=89.80 \pm 0.05 degrees.Comment: Accepted for publication in Astronomy and Astrophysic

L’affaire Plamondon : un cas d’antisémitisme à Québec au début du xxe siècle

L’affaire Plamondon compte parmi les procès célèbres de l’histoire judiciaire québécoise. Cette affaire commence par une conférence à caractère antisémite prononcée à Québec, en 1910, par Jacques-Édouard Plamondon. Au cours des semaines qui suivent, la presse se divise et des Juifs sont victimes d’agressions. Deux Juifs, qui souhaitent éviter que les choses dégénèrent, intentent une poursuite en dommages-intérêts pour libelle diffamatoire. L’action est rejetée en première instance, mais accueillie en appel. Au regard du droit, ce procès suscite de l’intérêt en ce qu’il reflète les tensions qui divisent la société, révèle la confiance que la communauté juive met dans l’institution judiciaire et amène une reconnaissance, en certaines circonstances, de la diffamation collective. Ce procès est aussi une illustration des formes spécifiques que constituent le scandale, l’affaire et la cause suivant une approche sociologique.The Plamondon case stands out among the famous trials in Québec judicial history. The case stemmed from anti-Semitic content in a lecture delivered in Québec by Jacques-Édouard Plamondon in 1910. During the weeks following the lecture, members of the press were at odds with one another and some Jews fell victim to agression. Two members of the Jewish community, seeking to avoid an increasingly embittered situation, took legal action on grounds of defamation. The suit was quashed in court of first instance, then reinstated on appeal. At law, this case raises interest since it sheds light on tensions that rend society, underscores the trust that the Jewish community invests in the courts and leads to a partial recognition in given circumstances of collective defamation. The proceedings also illustrate the specific forms of scandal, controversy and cause seen from a sociological viewpoint

Une relecture de l'arrêt Matamajaw Salmon Club

The case of Matamajaw Salmon Club v. Duchaine1 certainly remains one of the notorioustly outstanding decisions on a civil law issue handed down by the Privy Council. For many, the decision seems difficult to reconciliate with the civil law concept of ownership. None the less, most authors and judges attempt to minimize the incoherency. Here the decision is first presented and then the ration decidendi is analysed while its impact on the concept of property is considered