3,683 research outputs found

    Turkey's global strategy: introduction: the sources of Turkish grand strategy - ‘strategic depth’ and ‘zero-problems’ in context

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    The dramatic changes in Turkish foreign policy and strategy in its regional and international relations in the fi rst decade of the new century stands in sharp contrast with that of its immediate past. After the end of the Cold War, Turkey was a prickly power in a tough neighbourhood, one that included two major zones of instability, the Balkans and the Middle East. On three separate occasions, Turkey came to the brink of war with its neighbours: Armenia in 1992, Greece in 1996 and Syria in 1998. Regular military incursions were launched into Northern Iraq; in the Aegean, continuous tactical military provocations between the Greek and Turkish air force took place. Little movement was evident with regard to Cyprus and at one point Turkey even threatened to annex the northern part of the island. Relations with post-Cold War Russia were tentative and burdened by a long history of tension and conflict. Relations with Iran were soured by the Kurdish conflict and political Islam. Turkey’s overall approach to its neighbours was characterised by confrontation, mistrust, and the use of threats and force. Yet, despite tensions over domestic issues such as human rights, widespread use of torture, and the situation of the Kurdish minority, Turkey remained a strong transatlantic partner

    Inference of epidemiological parameters from household stratified data

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    We consider a continuous-time Markov chain model of SIR disease dynamics with two levels of mixing. For this so-called stochastic households model, we provide two methods for inferring the model parameters---governing within-household transmission, recovery, and between-household transmission---from data of the day upon which each individual became infectious and the household in which each infection occurred, as would be available from first few hundred studies. Each method is a form of Bayesian Markov Chain Monte Carlo that allows us to calculate a joint posterior distribution for all parameters and hence the household reproduction number and the early growth rate of the epidemic. The first method performs exact Bayesian inference using a standard data-augmentation approach; the second performs approximate Bayesian inference based on a likelihood approximation derived from branching processes. These methods are compared for computational efficiency and posteriors from each are compared. The branching process is shown to be an excellent approximation and remains computationally efficient as the amount of data is increased

    A Complete Spectroscopic Survey of the Milky Way satellite Segue 1: Dark matter content, stellar membership and binary properties from a Bayesian analysis

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    We introduce a comprehensive analysis of multi-epoch stellar line-of-sight velocities to determine the intrinsic velocity dispersion of the ultrafaint satellites of the Milky Way. Our method includes a simultaneous Bayesian analysis of both membership probabilities and the contribution of binary orbital motion to the observed velocity dispersion within a 14-parameter likelihood. We apply our method to the Segue 1 dwarf galaxy and conclude that Segue 1 is a dark-matter-dominated galaxy at high probability with an intrinsic velocity dispersion of 3.7^{+1.4}_{-1.1} km/sec. The dark matter halo required to produce this dispersion must have an average density of 2.5^{+4.1}_{-1.9} solar mass/pc^3 within a sphere that encloses half the galaxy's stellar luminosity. This is the highest measured density of dark matter in the Local Group. Our results show that a significant fraction of the stars in Segue 1 may be binaries with the most probable mean period close to 10 years, but also consistent with the 180 year mean period seen in the solar vicinity at about 1 sigma. Despite this binary population, the possibility that Segue 1 is a bound star cluster with the observed velocity dispersion arising from the orbital motion of binary stars is disfavored by the multi-epoch stellar velocity data at greater than 99% C.L. Finally, our treatment yields a projected (two-dimensional) half-light radius for the stellar profile of Segue 1 of 28^{+5}_{-4} pc, in excellent agreement with photometric measurements.Comment: 15 pages, 19 figure

    Life-Cycle Cost Modelling of Pneumatic Conveying Pipelines for the Lean Phase Transport Condition

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    Determination of the pressure requirements, volumetric flow rate and optimal pipeline diameter is key to selecting a compressor for dilute-phase conveying. Thus, a new methodology has been developed for determining these attributes for pneumatic conveying systems. There are two key costs involved in the design of pneumatic conveying pipelines, i.e. operational cost and capital cost. The methodology calculates these costs and formulates the optimal pipeline diameter based on the minimum conveying costs plus capital cost. This methodology displays the relationship between pressure drop and volumetric flow rate for the conveying costs. This will also allow for an optimal life cycle cost prediction

    Product structures for Legendrian contact homology

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    Legendrian contact homology (LCH) is a powerful non-classical invariant of Legendrian knots. Linearization makes the LCH computationally tractable at the expense of discarding nonlinear (and non-commutative) information. To recover some of the nonlinear information while preserving computability, we introduce invariant cup and Massey products – and, more generally, an A∞ structure – on the linearized LCH. We apply the products and A∞ structure in three ways: to find infinite families of Legendrian knots that are not isotopic to their Legendrian mirrors, to reinterpret the duality theorem of the fourth author in terms of the cup product, and to recover higher-order linearizations of the LCH

    Against the oxidative damage theory of aging: superoxide dismutases protect against oxidative stress but have little or no effect on life span in Caenorhabditis elegans

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    The superoxide radical (O-2(-)) has long been considered a major cause of aging. O-2(-) in cytosolic, extracellular, and mitochondrial pools is detoxified by dedicated superoxide dismutase (SOD) isoforms. We tested the impact of each SOD isoform in Caenorhabditis elegans by manipulating its five sod genes and saw no major effects on life span. sod genes are not required for daf-2 insulin/IGF-1 receptor mutant longevity. However, loss of the extracellular Cu/ZnSOD sod-4 enhances daf-2 longevity and constitutive diapause, suggesting a signaling role for sod-4. Overall, these findings imply that O-2(-) is not a major determinant of aging in C. elegans
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