The Processing of Fads and Fashions by Cultural Industries: An Organization-Set Analysis

http://deepblue.lib.umich.edu/bitstream/2027.42/50848/1/67.pd

Stress-Energy Tensor for the Massless Spin 1/2 Field in Static Black Hole Spacetimes

The stress-energy tensor for the massless spin 1/2 field is numerically computed outside and on the event horizons of both charged and uncharged static non-rotating black holes, corresponding to the Schwarzschild, Reissner-Nordstrom and extreme Reissner-Nordstr\"om solutions of Einstein's equations. The field is assumed to be in a thermal state at the black hole temperature. Comparison is made between the numerical results and previous analytic approximations for the stress-energy tensor in these spacetimes. For the Schwarzschild (charge zero) solution, it is shown that the stress-energy differs even in sign from the analytic approximation. For the Reissner-Nordstrom and extreme Reissner-Nordstrom solutions, divergences predicted by the analytic approximations are shown not to exist.Comment: 5 pages, 4 figures, additional discussio

Rethinking Appropriateness of Actions in Environmental Decisions: Connecting Interest and Identity Negotiation with Plural Valuation

Issues of interest, identity and values intertwine in environmental conflicts, creating challenges that cannot generally be overcome using rationalities grounded in generalised argumentation and abstraction. To address the growing need to engage interests and identities along with plural values in the conservation of biodiversity and ecological systems, we introduce the concept of ‘appropriateness of actions’ and ground it in a relational understanding of environmental ethics. A determination of appropriateness for actions comes from combining outputs from value elicitation with those of interest and identity negotiation in ways that are salient to specific people and their relationships to specific places. Drawing on the Blue Mountain Forest Partnership in the Pacific Northwest, we propose factors of success for supporting appropriate actions: 1) understanding context and identifying key stakeholders; 2) surfacing a diversity of interests and building system-level trust; 3) building empathy for different identities grounded in specific places; 4) eliciting diverse values and seeking to understand their links to worldviews and knowledge systems and; 5) seeking out appropriate actions

Surface potential at a ferroelectric grain due to asymmetric screening of depolarization fields

Nonlinear screening of electric depolarization fields, generated by a stripe domain structure in a ferroelectric grain of a polycrystalline material, is studied within a semiconductor model of ferroelectrics. It is shown that the maximum strength of local depolarization fields is rather determined by the electronic band gap than by the spontaneous polarization magnitude. Furthermore, field screening due to electronic band bending and due to presence of intrinsic defects leads to asymmetric space charge regions near the grain boundary, which produce an effective dipole layer at the surface of the grain. This results in the formation of a potential difference between the grain surface and its interior of the order of 1 V, which can be of either sign depending on defect transition levels and concentrations. Exemplary acceptor doping of BaTiO3 is shown to allow tuning of the said surface potential in the region between 0.1 and 1.3 V.Comment: 14 pages, 11 figures, submitted to J. Appl. Phy

Cerebral magnetic resonance elastography in supranuclear palsy and idiopathic Parkinson's disease

Detection and discrimination of neurodegenerative Parkinson syndromes are challenging clinical tasks and the use of standard T1- and T2-weighted cerebral magnetic resonance (MR) imaging is limited to exclude symptomatic Parkinsonism. We used a quantitative structural MR-based technique, MR-elastography (MRE), to assess viscoelastic properties of the brain, providing insights into altered tissue architecture in neurodegenerative diseases on a macroscopic level. We measured single-slice multifrequency MRE (MMRE) and three-dimensional MRE (3DMRE) in two neurodegenerative disorders with overlapping clinical presentation but different neuropathology — progressive supranuclear palsy (PSP: N = 16) and idiopathic Parkinson's disease (PD: N = 18) as well as in controls (N = 18). In PSP, both MMRE (Δμ = − 28.8%, Δα = − 4.9%) and 3DMRE (Δ|G*|: − 10.6%, Δφ: − 34.6%) were significantly reduced compared to controls, with a pronounced reduction within the lentiform nucleus (Δμ = − 34.6%, Δα = − 8.1%; Δ|G*|: − 7.8%, Δφ: − 44.8%). MRE in PD showed a comparable pattern, but overall reduction in brain elasticity was less severe reaching significance only in the lentiform nucleus (Δμ n.s., Δα = − 7.4%; Δ|G*|: − 6.9%, Δφ: n.s.). Beyond that, patients showed a close negative correlation between MRE constants and clinical severity. Our data indicate that brain viscoelasticity in PSP and PD is differently affected by the underlying neurodegeneration; whereas in PSP all MRE constants are reduced and changes in brain softness (reduced μ and |G*|) predominate those of viscosity (α and φ) in PD

Eastern Asian emissions of anthropogenic halocarbons deduced from aircraft concentration data

The Montreal Protocol restricts production of ozone-depleting halocarbons worldwide. Enforcement of the protocol has relied mainly on annual government statistics of production and consumption of these compounds (bottom-up approach). We show here that aircraft observations of halocarbon:CO enhancement ratios on regional to continental scales can be used to infer halocarbon emissions, providing independent verification of the bottom-up approach. We apply this top-down approach to aircraft observations of Asian outflow from the TRACE-P mission over the western Pacific (March April 2001) and derive emissions from eastern Asia (China, Japan, and Korea). We derive an eastern Asian carbon tetrachloride (CCl ) source of 21.5 Gg yr , several-fold larger than previous estimates and amounting to 30% of the global budget for this gas. Our emission estimate for CFC-11 from eastern Asia is 50% higher than inventories derived from manufacturing records. Our emission estimates for methyl chloroform (CH ) and CFC-12 are in agreement with existing inventories. For halon 1211 we find only a strong local source originating from the Shanghai area. Our emission estimates for the above gases result in a 40% increase in the ozone depletion potential (ODP) of Asian emissions relative to previous estimates, corresponding to a 10% global increase in ODP

Spatially resolved acoustic spectroscopy for texture imaging in powder bed fusion nickel superalloys

© 2019 Author(s). There is a clear industrial pull to fabricate high value components using premium high temperature aerospace materials by additive manufacturing. Inconveniently, the same material properties which allow them to perform well in service render them difficult to process via powder bed fusion. Current build systems are charac-terised by high defect rates and erratic microstructure, leading to components with inferior mechanical properties. The work presents microstructural texture imaging of powder-bed fusion components by a non-contact laser ultrasonic method, Spatially Resolved Acoustic Spectroscopy (SRAS). In short, this work demonstrates the ability to SRAS to detect and characterise meso-scale crystalline texture features. Probing samples manufactured by powder bed fusion, in the common nickel based aerospace superalloy Inconel 718, it has been shown the the primary crystalline orientation of can be inferred from the measured velocity, with good agreement with Electron Backscatter Diffraction. The studied sample was found to have a microstructure formation that bore a heavy resemblance to the chosen scanning pattern, with clear influence from the geometry through varying scan vector length and island-boundary scan strategy. This work forms part of a progression towards deployment of a SRAS system as an in-situ inspection solution for PBF

Updated Parameters and a New Transmission Spectrum of HD 97658b

Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD 97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight MOST transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1–1.7 μm reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are inconclusive, as no model provides an excellent match to our data. Nonetheless, we find that atmospheres with high C/O ratios (C/O ≳ 0.8) and metallicities of ≳100× solar metallicity are favored. We combine the mid-transit times from all of the new Spitzer and MOST observations and obtain an updated orbital period of P = 9.489295 ± 0.000005, with a best-fit transit time center at T₀ = 2456361.80690 ± 0.00038 (BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34 ± 2 days) and stellar activity cycle (9.6 yr) of the host star HD 97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000 K and with sizes between 1 R⊕ and 4 R⊕. We find that at least a third of small planets cooler than 1000 K can be well characterized using James Webb Space Telescope, and of those, HD 97658b is ranked fifth, meaning that it remains a high-priority target for atmospheric characterization