515 research outputs found

    U.S.-Canada High Technology Trade Issues

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    Canada-United States Economic Ties: The Technology Context, high technology and trad

    The United States Policy toward Inward Foreign Direct Investment

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    This paper presents the perspective of the author, a trade and investment policy official, on the most significant aspects of the United States policy toward foreign direct investment. The summary in this section is presented to give the author\u27s policy viewpoint in order to assist the reader in evaluating the paper\u27s arguments... United States policy, at both the federal and local levels, reflects a strong positive attitude concerning the general benefits of inward foreign direct investment. While foreign ownership of United States assets is restricted in certain sectors, the general United States approach is one of national treatment --i.e., foreign investors are treated as favorably as domestic investors with respect to the application of United States laws and regulations

    Experimental Investigation of the Secondary and Backscatter Electron Emission From New Spacecraft Surface Materials

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    The emission of secondary and backscattered electrons influences spacecraft surface potentials and the surrounding plasma. Modern spacecraft use new materials for which secondary emission properties have been unavailable. In this work, the total electron yield (i.e., the sum of secondary and backscattered electron yields) was measured for niobium-C103 alloy, molybdenum Titanium, Zirconium, Molybdenum (TZM) alloy, tantalum-tungsten alloy, Elgiloy®, graphite lubricant (DAG 213®), and titanium nitride. The surface properties of tungsten were also measured for comparison with past test data. The materials were readied as spacecraft flight materials and temperature-treated ( annealed ) to predicted peak flight temperatures. The yield properties for 10 eV-5 keV incident electron energies for all samples were measured. Both unannealed and annealed states were tested, except DAG 213, which was only tested annealed. Three-parameter and four-parameter models were used to fit the secondary and backscattered electron yield data, respectively. The emitted electron energy distributions are also obtained and fit with a Chung-Everhart model for secondary electrons and a Gaussian function for backscattered electrons. The secondary and backscattered electrons\u27 current densities were calculated for different ambient plasma conditions. For ready reference, the normalized primary electron, secondary electron, and backscattered electron current densities versus ambient electron temperature were computed and plotted from 1 eV to 8 keV

    Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves Instruments: Radio Flux Density Variations with Frequency

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    We have performed a statistical study of 152152 Type III radio bursts observed by Solar TErrestrial RElations Observatory (STEREO)/Waves between May 2007 and February 2013. We have investigated the flux density between 125125kHz and 1616MHz. Both high- and low-frequency cutoffs have been observed in 6060\,% of events suggesting an important role of propagation. As already reported by previous authors, we observed that the maximum flux density occurs at 11MHz on both spacecraft. We have developed a simplified analytical model of the flux density as a function of radial distance and compared it to the STEREO/Waves data.Comment: published in Solar Physic

    Elastic Scattering by Deterministic and Random Fractals: Self-Affinity of the Diffraction Spectrum

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    The diffraction spectrum of coherent waves scattered from fractal supports is calculated exactly. The fractals considered are of the class generated iteratively by successive dilations and translations, and include generalizations of the Cantor set and Sierpinski carpet as special cases. Also randomized versions of these fractals are treated. The general result is that the diffraction intensities obey a strict recursion relation, and become self-affine in the limit of large iteration number, with a self-affinity exponent related directly to the fractal dimension of the scattering object. Applications include neutron scattering, x-rays, optical diffraction, magnetic resonance imaging, electron diffraction, and He scattering, which all display the same universal scaling.Comment: 20 pages, 11 figures. Phys. Rev. E, in press. More info available at http://www.fh.huji.ac.il/~dani

    'Who do "they" cheer for?' Cricket, diaspora, hybridity and divided loyalties amongst British Asians

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    This article explores the relationship between British Asians' sense of nationhood, citizenship, ethnicity and some of their manifestations in relation to sports fandom: specifically in terms of how cricket is used as a means of articulating diasporic British Asian identities. Norman Tebbit's 'cricket test' is at the forefront of this article to tease out the complexities of being British Asian in terms of supporting the English national cricket team. The first part of the article locates Tebbit's 'cricket test' within the wider discourse of multiculturalism. The analysis then moves to focus on the discourse of sports fandom and the concept of 'home team advantage' arguing that sports venues represent significant sites for nationalist and cultural expression due to their connection with national history. The article highlights how supporting 'Anyone but England', thereby rejecting ethnically exclusive notions of 'Englishness' and 'Britishness', continues to be a definer of British Asians' cultural identities. The final section situates these trends within the discourse of hybridity and argues that sporting allegiances are often separate from considerations of national identity and citizenship. Rather than placing British Asians in an either/or situation, viewing British 'Asianness' in hybrid terms enables them to celebrate their traditions and histories, whilst also being proud of their British citizenship. © The Author(s) 2011

    Observations of Energetic-particle Population Enhancements along Intermittent Structures near the Sun from the Parker Solar Probe

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    Observations at 1 au have confirmed that enhancements in measured energetic-particle (EP) fluxes are statistically associated with "rough" magnetic fields, i.e., fields with atypically large spatial derivatives or increments, as measured by the Partial Variance of Increments (PVI) method. One way to interpret this observation is as an association of the EPs with trapping or channeling within magnetic flux tubes, possibly near their boundaries. However, it remains unclear whether this association is a transport or local effect; i.e., the particles might have been energized at a distant location, perhaps by shocks or reconnection, or they might experience local energization or re-acceleration. The Parker Solar Probe (PSP), even in its first two orbits, offers a unique opportunity to study this statistical correlation closer to the corona. As a first step, we analyze the separate correlation properties of the EPs measured by the Integrated Science Investigation of the Sun (IS⊙IS) instruments during the first solar encounter. The distribution of time intervals between a specific type of event, i.e., the waiting time, can indicate the nature of the underlying process. We find that the IS⊙IS observations show a power-law distribution of waiting times, indicating a correlated (non-Poisson) distribution. Analysis of low-energy (~15 – 200 keV/nuc) IS⊙IS data suggests that the results are consistent with the 1 au studies, although we find hints of some unexpected behavior. A more complete understanding of these statistical distributions will provide valuable insights into the origin and propagation of solar EPs, a picture that should become clear with future PSP orbits

    Observations of the 2019 April 4 Solar Energetic Particle Event at the Parker Solar Probe

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    A solar energetic particle event was detected by the Integrated Science Investigation of the Sun (IS⊙IS) instrument suite on Parker Solar Probe (PSP) on 2019 April 4 when the spacecraft was inside of 0.17 au and less than 1 day before its second perihelion, providing an opportunity to study solar particle acceleration and transport unprecedentedly close to the source. The event was very small, with peak 1 MeV proton intensities of ~0.3 particles (cm² sr s MeV)⁻¹, and was undetectable above background levels at energies above 10 MeV or in particle detectors at 1 au. It was strongly anisotropic, with intensities flowing outward from the Sun up to 30 times greater than those flowing inward persisting throughout the event. Temporal association between particle increases and small brightness surges in the extreme-ultraviolet observed by the Solar TErrestrial RElations Observatory, which were also accompanied by type III radio emission seen by the Electromagnetic Fields Investigation on PSP, indicates that the source of this event was an active region nearly 80° east of the nominal PSP magnetic footpoint. This suggests that the field lines expanded over a wide longitudinal range between the active region in the photosphere and the corona
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