212 research outputs found
Itinerant-electron magnetism: the importance of many-body correlations
Do electrons become ferromagnetic just because of their repulisve Coulomb
interaction? Our calculations on the three-dimensional electron gas imply that
itinerant ferromagnetim of delocalized electrons without lattice and band
structure, the most basic model considered by Stoner, is suppressed due to
many-body correlations as speculated already by Wigner, and a possible
ferromagnetic transition lowering the density is precluded by the formation of
the Wigner crystal.Comment: published version including supplementary materia
Feminist Reasoning about Reason
In this paper, I focus on the postmodern feminist criticism of reason. I argue that postmodern feminism is in part a response to political concerns over valuing womens\u27 differences but that the philosophical ideas it propounds cannot fully address these political concerns. Moreover, postmodern feminism branches into two directions, partly in the face of criticisms directed at it. The one becomes a form of intellectual play, the other becomes imbued with ethic of care assumptions. I recommend that feminism of sameness may provide a better vehicle than either postmodern or ethic of care feminism for addressing the `masculinist biases\u27 of Western reason
MOTOR CARRIER REGULATION AND ITS IMPACT ON SERVICE: AN ANALYSIS OF TEXAS FRESH FRUIT AND VEGETABLE SHIPPERS
Crop Production/Industries, Public Economics,
High torque DC motor fabrication and test program
The testing of a standard iron and standard alnico permanent magnet two-phase, brushless dc spin motor for potential application to the space telescope has been concluded. The purpose of this study was to determine spin motor power losses, magnetic drag, efficiency and torque speed characteristics of a high torque dc motor. The motor was designed and built to fit an existing reaction wheel as a test vehicle and to use existing brass-board commutation and torque command electronics. The results of the tests are included in this report
Imaging Discontinuities in the Lithospheric Mantle Using a New, Automated Ps and Sp Receiver Function Workflow
Postponed access: the file will be accessible after 2022-11-17Over the last decades, the receiver function technique has been widely established as a standard tool for surveying sharp changes in elastic properties of the Earth’s crust and upper mantle. To date, very few studies have attempted to use receiver functions for global imaging. To overcome the lack of toolsets for global receiver function imaging, I have developed PyGLImER - a Python-based software suite capable of creating global images from both P-to-S and S-to-P converted teleseismic waves via a comprehensive receiver function workflow. In this thesis, I discuss the functionalities of PyGLImER and demonstrate its efficiency, effectiveness, and robustness on synthetic and real earthquake data examples. I show images from receiver functions, binned and stacked by conversion point, from four regions, one of which - North America - is the focus of a more thorough discussion. The receiver function survey of the North American continent presented here is of unprecedented size resulting in high-resolution images which allow to accurately constrain the depth of the cratonic lithosphere-asthenosphere boundary, make new observations of a positive correlation between the number of midlithospheric discontinuities (MLD) and the age of the lithosphere, and identify a sharp transition from the Proterozoic belts dominated by dipping structures to Archean cratons dominated by horizontal and subhorizontal MLDs. Those observations lead me to make the following hypotheses: (1) Thick continental lithosphere is formed by cyclic (i.e., periodic) processes. (2) In hotter Archean times, the formation of continents was dominated by plume-induced mechanisms (subcretion) causing horizontal MLDs, whereas, in the later Precambrian, the dominance shifted towards subduction accretion. (3) Considering (1) and (2), I deem MLDs to be caused by layers of frozen melt as previously suggested by petrological studies.Master's Thesis in Earth ScienceGEOV399MAMN-GEO
EVALUATING RISK MANAGEMENT STRATEGIES FOR NON-IRRIGATED SMALL GRAIN PRODUCERS
Risk management strategies (market and insurance based) are evaluated for selected small grain producers in the Pacific Northwest using expected utility maximization. Equivalent variation (EV) compares alternative risk management portfolios to cash sales under specified restrictions and conditions. Resulting EV's are strongly influenced by government payments, and hedging-based strategies are not used when counter cyclical payments are included in government programs. Optimum risk management portfolios include extensive coverage by insurance-based products only when such products have premiums that are heavily subsidized, or have premiums with no significant expense load.Risk and Uncertainty,
THE CROWDING OUT EFFECTS OF THE 2002 FARM BILL ON HEDGING: EVIDENCE FROM PACIFIC NORTHWEST GRAIN FARMS
The 2002 Food Security and Rural Investment (FSRI) Act introduced a price protection program called Counter Cyclical Payments (CCP) to major grain producers in the US. The CCP program is an addition to the Loan Deficiency Payment (LDP) and Direct Payment (DP) programs from the previous 1996 Federal Agriculture Improvement and Reform (FAIR) Act. At the same time, US federally subsidized crop revenue insurance programs also protect farmers from market and production risks. These government policy programs may crowd out the traditional price risk management role of hedging in commodity futures markets.Agricultural and Food Policy, Crop Production/Industries,
EFFECTS OF INCREASING PANAMA CANAL TOLL RATES ON U.S. GRAIN EXPORTS
Some believe Panama Canal toll rates will increase dramatically as Panama's sovereignty over the Canal becomes complete at the end of this century. This paper focuses on the ability of Panama Canal management to extract additional toll revenues from United States grain traversing the Canal and the impact of increased toll rates on export grain flows. Analyses show toll rates established by a revenue-maximizing Canal management would exceed historical and current rates. A monopolizing Canal operator would have moderately increased Pacific port exports in the mid-1970Â’s; whereas, in the 1979-82 period, Pacific port flows would have exceeded historical levels.International Relations/Trade,
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