Nous nous intéressons à l’évolution des rapports économiques entre la Rome républicaine et l’Égypte lagide et notamment à la commercialisation du blé égyptien au bénéfice de Rome. L’étude diachronique des échanges économiques entre les deux pays nous mène à nous confronter avec l’évolution de leurs rapports politiques réciproques. Nous poursuivons notre enquête pour le premier siècle d’Empire Romain. Nous nous attarderons sur l’étude de la gestion du blé égyptien au sein du système annonaire, sans pour autant négliger les acteurs « privés » du commerce du blé sous les Empereurs julio-claudiens. Nous articulerons notre recherche autour des trois axes principaux: les institutions, les acteurs et les structures du commerce du blé. / We will study the history of economic relationships between Roman Republic and Ptolemaic Egypt, focusing on Egyptian grain trade in western Mediterranean basin, especially in Rome and Puteoli. Our diachronic approach about economical exchanges between these two countries will retain attention on their reciprocal political relationships. We will continue our research during the first century of Roman Empire. We will interest to Egyptian grain administration by the annona and the imperial supply structures. We will bring interest also on private grain trade under Julio-Claudians emperors. We will develop our research on three fundamental items: the institutions, the actors and the structures of the grain trade.

Agricultural commodity derivatives were first introduced in South Africa in 1996 after the deregulation of the former marketing system. In the context of its proposed functions, namely price discovery and risk management, the question arose as to whether the futures market developed over time to performed its role efficiently. According to the Efficient Markets Hypothesis (EMH) an efficient market is one that accurately incorporates all information available at any point in time. The purpose of the research was to address the issue of price discovery efficiency, firstly, focusing on the weak-form methodology. Secondly, considering the behaviour of futures prices over time, the study addressed the concern of anomalies in daily returns – phenomena contradictory to the EMH by implication. Thirdly, as a means of defining the sources of inefficiency, the role of scheduled public information and its impact on futures prices was examined. Therefore, the primary objective of the research was to investigate and identify the main components of agricultural futures market inefficiency within the unique price formation structure of South African grain markets. The assessment of this problem is important in terms of evaluating the growth and development of the futures market for different grain commodities to date. The Exchange needs to review rules and regulations on a frequent basis in order to ensure proper functioning at all times especially in the case of a relatively new and fast growing market. The study contributed to the knowledge of understanding the price adjustment process and its implications for market efficiency in the context of the three grain markets considered. The weak-form efficiency was tested using a co-integration based model. Analysing daily spot and futures prices of white maize, yellow maize, and wheat, results indicated that all three markets were efficient and unbiased. Non-parametric tests revealed the significant presence of day-of-the-week and turn-of-the-month effects in the futures returns of the three commodities. Further non-parametric analyses suggested a high degree of uncertainty in futures returns around scheduled agricultural and macroeconomic information release dates also contributing significantly to the identified anomalies. It was concluded that (1) the markets’ ability to anticipate the contents of future information to be released, (2) the current skewed size distribution of broking members, (3) the significant role of the R/$ exchange rate in the price formation process of South African grains and, therefore, (4) the relationship to and influence of the broader economy enhanced the return effects (anomalies) creating opportunity for profitable arbitrage. This conclusion was mainly attributed to South Africa’s status as a price-taker in the world grain complex as well as the relatively short existence of the local agricultural futures markets.

La place assignée à Gabriel Bonnot de Mably (1709-1785) au sein de l'historiographie contemporaine est ambigüe. Il a été longtemps considéré comme l'une des influences majeures de la Révolution française puis comme l'un des précurseurs de la doctrine communiste. Il a fallu attendre les travaux de l’École de Cambridge en particulier ceux de Pocock, pour qu'un consensus s'opère : Mably est devenu l'archétype du républicain classique en France au XVIIIe siècle. L'objectif de cette thèse est d'interroger l'inscription de Mably dans cette tradition républicaine, en prenant en compte deux éléments fondateurs de sa pensée : i) Sa vraisemblable proximité avec Jacques Vincent de Gournay et la « science du commerce », ii) les influences du droit naturel moderne et en particulier celle de John Locke. Ces éléments conduisent à réévaluer la controverse entre Mably et les physiocrates. Il est proche d'accepter une société fondée sur l'intérêt personnel et le calcul individuel, mais seule une solution républicaine : la participation à la vie collective de chaque citoyen, est en mesure de garantir la théorie, dite libérale, du droit naturel. Et si Mably s'oppose à la libéralisation du commerce des grains défendue par les physiocrates, c'est pour défendre les principes de la « science du commerce », c'est-à-dire un libre-échange encadré. Ainsi, en portant une attention particulière aux influences intellectuelles de Mably, en particulier celles de Locke et de Gournay, cette thèse met en lumière une nouvelle grille interprétative, une position médiane, dans laquelle le langage républicain de Mably est au service de sa théorie du droit naturel. / The place assigned to Gabriel Bonnot de Mably (1709-1785) in contemporary historiography is ambiguous. He is portrayed as a main influence of the French Revolution then as a precursor to the communist doctrine. Recently, the Cambridge School works' and in particular Pocock's works led to a consensus: Mably was the archetype of classical republicanism in France in 18th century. The aim of this thesis is to examine the membership of Mably in this republican tradition taking into account two fundamental elements of his thought: i) his connection with Vincent de Gournay and the "science of commerce"; ii) the influences of modern natural law and in particular that of John Locke. This leads to reassess the controversy between Mably and Physiocrats. He seems close to accepting the Physiocratie argument for a society based on self-interest and individual calculation. But only a republican solution, the participation in the collective life of every citizen, is able to secure the theory, called liberal, of natural law. His opposition to the liberalization of grain tracte results from a defense of the "science of commerce" i.e. a framed free trade. Thus, paying particular attention to Mably's intellectual influences particularly those of Locke and Gournay, this thesis highlights a new interpretative grid, a rniddle position, in which the republican language of Mably secures his theory of natural law.