The Topology of Central Counterparty Clearing Networks and Network Stability

□ This paper derives a measure of central counterparty (CCP) clearing-network risk that is based on the probability that the maximum exposure (the N-th order statistic) of a CCP to an individual general clearing member is large. Our analytical derivation of this probability uses the theory of Laplace asymptotics, which is related to the large deviations theory of rare events. The theory of Laplace asymptotics is an area of applied probability that studies the exponential decay rate of certain probabilities and is often used in the analysis of the tails of probability distributions. We show that the maximum-exposure probability depends on the topology, or structure, of the clearing network. We also derive a CCP's Maximum-Exposure-at-Risk, which provides a metric for evaluating the adequacy of the CCP's and general clearing members’ loss-absorbing financial resources during rare but plausible market conditions. Based on our analysis, we provide insight into how clearing-network structure can affect the maximum-exposure risk of a CCP and, thereby, network stability. We show that the rate function (the exponential decay rate) of the maximum-exposure probability is informative and can be used to compare the relative maximum-exposure risks across different network configurations.     

Embodied Cognition,Representationalism, and Mechanism: A Review and Analysis

Embodied cognition has attracted significant attention within cognitive science and related fields in recent years. It is most noteworthy for its emphasis on the inextricable connection between mental functioning and embodied activity and thus for its departure from standard cognitive science's implicit commitment to the unembodied mind. This article offers a review of embodied cognition's recent empirical and theoretical contributions and suggests how this movement has moved beyond standard cognitive science. The article then clarifies important respects in which embodied cognition has not departed fundamentally from the standard view. A shared commitment to representationalism, and ultimately, mechanism, suggest that the standard and embodied cognition movements are more closely related than is commonly acknowledged. Arguments against representationalism and mechanism are reviewed and an alternative position that does not entail these conceptual undergirdings is offered.     

Is He a Hero or a Weirdo? How Norm Violations Influence the Halo Effect

First impressions are often influenced by the context in which we experience them. Many factors, such as behavior, appearance, and our own personal attitudes can affect the way that these perceptions are constructed. The present experiment sought to examine the effect of positive norm violation on females’ perceptions of male facial attractiveness. Two male faces (attractive and unattractive) with similar features were partnered with two scenarios of positive norm violation (low intensity and high intensity) while being rated on personality characteristics. Two separate halo effects were hypothesized in the experiment: attractiveness and high violation. An interaction effect in the form of a magnified halo was also predicted. Participants were 178 female college students. Results showed favorable ratings for the attractive male face and the low violation condition, with the attractive, low violation condition receiving the most positive results. Data supported a significant effect for positive norm violation, but not for male facial attractiveness. A significant interaction effect between the two variables was also observed.     

P-Value Precision and Reproducibility

P-values are useful statistical measures of evidence against a null hypothesis. In contrast to other statistical estimates, however, their sample-to-sample variability is usually not considered or estimated, and therefore not fully appreciated. Via a systematic study of log-scale p-value standard errors, bootstrap prediction bounds, and reproducibility probabilities for future replicate p-values, we show that p-values exhibit surprisingly large variability in typical data situations. In addition to providing context to discussions about the failure of statistical results to replicate, our findings shed light on the relative value of exact p-values vis-a-vis approximate p-values, and indicate that the use of *, **, and *** to denote levels .05, .01, and .001 of statistical significance in subject-matter journals is about the right level of precision for reporting p-values when judged by widely accepted rules for rounding statistical estimates.     

HOW ‘NATIVES’ THINK

Marshall Sahlins. How 'natives' think: about Captain Cook, for example (Chicago: University of Chicago Press. 1995. x, 318pp., maps, table, plates, figures, bibliography, index. $40.95. ISBN 0 226 73368 8.     

AT WAR

Technological supremacy means that the West can avoid getting up close and personal to kill. Our legacies of imperial power ensure that our wars are fought ‘over there’, and men in post-industrial societies are disassociated from the death embracing culture of the warrior. However, in the aftermath of September 11, we have entered a new era of global militarization – the shadowed world of the War on Terror. It confronts us with the historical changes in men's relationship to war, and how masculinity has been shaped by the processes of formalization and informalization. It opens up a new kind of front, with an enemy who is claimed to be everywhere, and a military-market complex that is denationalizing war in its promotion of a neo-liberal imperialism.     

Decomposition of urban atmospheric carbon in Sonoran Desert soils

Urban atmospheres can have high concentrations of particulate organic carbon (oC) but the rate and fate oC deposition in near-urban ecosystems are rarely quantified. We collected atmospheric particulate matter in Phoenix, AZ and applied these samples to Sonoran Desert soils in a series of laboratory incubation experiments. The addition of fine particulate matter (<2.5 μm aerodynamic diameter) increased microbial respiration in soils collected from the interspaces between desert shrubs. The increase in soil respiration was equivalent to 25% to 30% of the added oC. In contrast, we did not detect increases in respiration when coarse particulate matter (>2.5 μm aerodynamic diameter) was added to interspace soils, suggesting that coarse particulate oC is recalcitrant to microbial decomposition. Due to comparatively higher background levels of C mineralization, we rarely detected changes in microbial respiration when fine or coarse particulate oC was added to soils collected beneath shrub canopies. We measured total atmospheric C concentrations within and surrounding Phoenix and, using inferential methods, estimated rates of deposition that ranged from 0.02 to 0.58 mg C m⁻² d⁻¹ for fine particles and from 0 to 6.15 mg C m⁻² d⁻¹ for coarse particles. Results show that fine atmospheric particulate matter deposited at low rates downwind of Phoenix is a labile oC substrate for soil heterotrophs. In contrast, oC deposited at higher rates as coarse particulate matter may accumulate in soils due to slow microbial decomposition rates.