A theory of social facts

Philosophy, Practical and Systematic TheologyD.Litt. et Phil. (Philosophy

Deformation Behavior of Foam Laser Targets Fabricated by Two-Photon Polymerization

Two-photon polymerization (2PP), which is a three-dimensional micro/nano-scale additive manufacturing process, is used to fabricate component for small custom experimental packages (“targets”) to support laser-driven, high-energy-density physics research. Of particular interest is the use of 2PP to deterministically print millimeter-scale, low-density, and low atomic number (CHO) polymer matrices (“foams”). Deformation during development and drying of the foam structures remains a challenge when using certain commercial acrylic photo-resins. Acrylic resins were chosen in order to meet the low atomic number requirement for the foam; that requirement precludes the use of low-shrinkage organic/inorganic hybrid resins. Here, we compare the use of acrylic resins IP-S and IP-Dip. Infrared and Raman spectroscopy are used to quantify the extent of the polymerization during 2PP vs. UV curing. The mechanical strength of beam and foam structures is examined, particularly the degree of deformation that occurs during the development and drying processes. The magnitude of the shrinkage is quantified, and finite element analysis is used in order to simulate the resulting deformation. Capillary drying forces during development are shown to be small and are likely below the elastic limit of the foam log-pile structures. In contrast, the substantial shrinkage in IP-Dip (~5–10%) causes large shear stresses and associated plastic deformation, particularly near constrained boundaries and locations with sharp density transitions. Use of IP-S with an improved writing procedure results in a marked reduction in deformation with a minor loss of resolution

Nonstationary Collisional Dynamics in Determining Nitric Oxide Laser-Induced Flourescence Spectra

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77237/1/AIAA-8783-947.pd

Estimating Systemic Risk in the International Financial System

Using a unique and comprehensive dataset, this paper develops and uses three distinct methods to quantify the risk of a systemic failure in the global banking system. We examine a sample of 334 banks (representing 80% of global bank equity) in 28 countries around 6 global financial crises (such as the Asian and Russian crises and September 11, 2001), and show that these crises did not create large probabilities of global financial system failure. First, we show that cumulative negative abnormal returns for the subset of banks not directly exposed to a negative shock (unexposed banks) rarely exceed a few percent. Second, we use structural models to obtain more precise point estimates of the likelihood of systemic failure. These estimates suggest that systemic risk is limited even during major financial crises. For example, maximum likelihood estimation of bank failure probabilities implied by equity prices suggests the Asian crisis induced less than a 1% increase in the probability of systemic failure. Third, we also obtain estimates of systemic risk implied by equity option prices of U.S. and European banks. The largest values are obtained for the Russian crisis and September 11 and these show increases in estimated average default probabilities of only around 1-2%. Taken together our results suggest statistically significant, but economically small, increases in systemic risk around even the worst financial crises of the last 10 years. Although policy responses are endogenous, the low estimated probabilities suggest that the distress of central bankers, regulators and politicians about the events we study may be overstated, and that current policy responses to financial crises and the existing institutional framework may be adequate to handle major macroeconomic events

Voltage-gated Nav channel targeting in the heart requires an ankyrin-G–dependent cellular pathway

Voltage-gated Nav channels are required for normal electrical activity in neurons, skeletal muscle, and cardiomyocytes. In the heart, Nav1.5 is the predominant Nav channel, and Nav1.5-dependent activity regulates rapid upstroke of the cardiac action potential. Nav1.5 activity requires precise localization at specialized cardiomyocyte membrane domains. However, the molecular mechanisms underlying Nav channel trafficking in the heart are unknown. In this paper, we demonstrate that ankyrin-G is required for Nav1.5 targeting in the heart. Cardiomyocytes with reduced ankyrin-G display reduced Nav1.5 expression, abnormal Nav1.5 membrane targeting, and reduced Na+ channel current density. We define the structural requirements on ankyrin-G for Nav1.5 interactions and demonstrate that loss of Nav1.5 targeting is caused by the loss of direct Nav1.5–ankyrin-G interaction. These data are the first report of a cellular pathway required for Nav channel trafficking in the heart and suggest that ankyrin-G is critical for cardiac depolarization and Nav channel organization in multiple excitable tissues

Regulatory ecotoxicity testing of nanomaterials – proposed modifications of OECD test guidelines based on laboratory experience with silver and titanium dioxide nanoparticles

Conservation Biolog

Phenotyping pipeline reveals major seedling root growth QTL in hexaploid wheat

Seedling root traits of wheat (Triticum aestivum L.) have been shown to be important for efficient establishment and linked to mature plant traits such as height and yield. A root phenotyping pipeline, consisting of a germination paper-based screen combined with image segmentation and analysis software, was developed and used to characterize seedling traits in 94 doubled haploid progeny derived from a cross between the winter wheat cultivars Rialto and Savannah. Field experiments were conducted to measure mature plant height, grain yield, and nitrogen (N) uptake in three sites over 2 years. In total, 29 quantitative trait loci (QTLs) for seedling root traits were identified. Two QTLs for grain yield and N uptake co-localize with root QTLs on chromosomes 2B and 7D, respectively. Of the 29 root QTLs identified, 11 were found to co-localize on 6D, with four of these achieving highly significant logarithm of odds scores (>20). These results suggest the presence of a major-effect gene regulating seedling root vigour/growth on chromosome 6D

Non-default Component of Sovereign Emerging Market Yield Spreads and its Determinants: Evidence from Credit Default Swap Market

This article shows that a sizable component of emerging market sovereign yield spreads is due to factors other than default risk, such as liquidity. The author estimates the non-default component of the yield spreads as the basis between the actual credit default swap (CDS) premium and the hypothetical CDS premium implied by emerging market bond yields. On average, the basis is large and positive for speculative-grade bonds and slightly negative for investment-grade bonds. The large positive basis for speculative-grade bonds supports the existence of speculation in the CDS market when the underlying's credit quality is bad. The author studies the effects of bond liquidity, liquidity in the CDS market, equity market performance, and macroeconomic variables on the non-default component of the emerging market yield spreads. The results show that bond liquidity has a significant and positive effect on the CDS–bond basis of investment-grade bonds. The results suggest that the liquid bonds of investment-grade bonds are more expensive relative to the prices implied their CDS premiums. However, the results are somewhat mixed and even contrary for the speculative-grade bond sample

Testing a dynamic field account of interactions between spatial attention and spatial working memory

Studies examining the relationship between spatial attention and spatial working memory (SWM) have shown that discrimination responses are faster for targets appearing at locations that are being maintained in SWM, and that location memory is impaired when attention is withdrawn during the delay. These observations support the proposal that sustained attention is required for successful retention in SWM: if attention is withdrawn, memory representations are likely to fail, increasing errors. In the present study, this proposal is reexamined in light of a neural process model of SWM. On the basis of the model’s functioning, we propose an alternative explanation for the observed decline in SWM performance when a secondary task is performed during retention: SWM representations drift systematically toward the location of targets appearing during the delay. To test this explanation, participants completed a color-discrimination task during the delay interval of a spatial recall task. In the critical shifting attention condition, the color stimulus could appear either toward or away from the memorized location relative to a midline reference axis. We hypothesized that if shifting attention during the delay leads to the failure of SWM representations, there should be an increase in the variance of recall errors but no change in directional error, regardless of the direction of the shift. Conversely, if shifting attention induces drift of SWM representations—as predicted by the model—there should be systematic changes in the pattern of spatial recall errors depending on the direction of the shift. Results were consistent with the latter possibility—recall errors were biased toward the location of discrimination targets appearing during the delay