Beyond Fashoda: Anglo-French security cooperation in Africa since St-Malo

Traditionally divided on security matters, France and Britain broke new ground when they signed the 1998 Saint-Malo agreement, promising to collaborate on defence and security, and pledging to cooperate bilaterally and in a ‘bi-multi’ fashion on Africa. This Anglo-French collaboration is the focus of this article, which begins by setting out the lack of UK–French security cooperation in Africa from the colonial to the early post-Cold War era. It then shows how there has been a degree of institutionalization of Anglo-French relations, alongside greater cooperation in terms of ESDP missions and the training of African peacekeepers. Next, this study explains the recent evolution of UK–French security relations in terms of neo-classical realist theory. Finally, it assesses the likelihood of closer Anglo-French security collaboration in the future

PET Studies of Cerebral Levodopa Metabolism: A Review of Clinical Findings and Modeling Approaches

[18F]Fluoro-3,4-dihydroxyphenyl-l-alanine (FDOPA) was one of the first successful tracers for molecular imaging by positron emission tomography (PET), and has proven immensely valuable for studies of Parkinson’s disease. Following intravenous FDOPA injection, the decarboxylated metabolite [18F] fluorodopamine is formed and trapped within terminals of the nigrostriatal dopamine neurons; reduction in the simple ratio between striatum and cerebellum is indicative of nigrostriatal degeneration. However, the kinetic analysis of dynamic FDOPA-PET recordings is formidably complex due to the entry into brain of the plasma metabolite O-methyl-FDOPA and due to the eventual washout of decarboxylated metabolites. Linear graphical analysis relative to a reference tissue input function is popular and convenient for routine clinical studies in which serial arterial blood samples are unavailable. This simplified approach has facilitated longitudinal studies in large patient cohorts. Linear graphical analysis relative to the metabolite-corrected arterial FDOPA input yields a more physiological index of FDOPA utilization, the net blood-brain clearance. Using a constrained compartmental model, FDOPA-PET recordings can be used to calculate the relative activity of the enzyme DOPA decarboxylase in living brain. We have extended this approach so as to obtain an index of steady-state trapping of [18F]fluorodopamine in synaptic vesicles. Although simple methods of image analysis are sufficient for the purposes of routine clinical studies, the more complex approaches have revealed hidden aspects of brain dopamine in personality, healthy aging, and in the pathophysiologies of Parkinson’s disease and schizophrenia

Private equity returns and disclosure around the world

We study the returns the venture capital and private equity investment from 221 venture capital and private equity funds that are part of 72 venture capital and private equity firms, 5040 entrepreneurial firms (3826 venture capital and 1214 private equity), and spanning 32 years (1971 - 2003) and 39 countries from North and South America, Europe and Asia. We make use of four main categories of variables to proxy for value-added activities and risks that explain venture capital and private equity returns: market and legal environment, VC characteristics, entrepreneurial firm characteristics, and the characteristics and structure of the investment. We show Heckman sample selection issues in regards to both unrealized and partially realized investments are important to consider for analysing the determinants of realized returns. We further compare the actual unrealized returns, as reported to investment managers, to the predicted unrealized returns based on the estimates of realized returns from the sample selection models. We show there exists significant systematic biases in the reporting of unrealized investments to institutional investors depending on the level of the earnings aggressiveness and disclosure indices in a country, as well as proxies for the degree of information asymmetry between investment managers and venture capital and private equity fund managers. Klassifikation: G24, G28, G31, G32, G3

Financing Entrepreneurs Better Canadian Policy for Venture Capital

Canadian policymakers should pursue new options for facilitating investment in innovation and entrepreneurship. Better venture capital policy is the place to start, because existing tools for delivering financial investment to start-ups are not succeeding.venture capital policy

Time-dependent, compositionally driven convection in the oceans of accreting neutron stars

We discuss the effect of chemical separation as matter freezes at the base of the ocean of an accreting neutron star, and the subsequent enrichment of the ocean in light elements and inward transport of heat through convective mixing. We extend the steady-state results of Medin & Cumming 2011 to transiently accreting neutron stars, by considering the time-dependent cases of heating during accretion outbursts and cooling during quiescence. Convective mixing is extremely efficient, flattening the composition profile in about one convective turnover time (weeks to months at the base of the ocean). During accretion outbursts, inward heat transport has only a small effect on the temperature profile in the outer layers until the ocean is strongly enriched in light elements, a process that takes hundreds of years to complete. During quiescence, however, inward heat transport rapidly cools the outer layers of the ocean while keeping the inner layers hot. We find that this leads to a sharp drop in surface emission at around a week followed by a gradual recovery as cooling becomes dominated by the crust. Such a dip should be observable in the light curves of these neutron star transients, if enough data is taken at a few days to a month after the end of accretion. If such a dip is definitively observed, it will provide strong constraints on the chemical composition of the ocean and outer crust.Comment: 22 pages, 11 figures, submitted to Ap