28,789 research outputs found
An Investigation into the Economic Thought of Medieval Arab-Islamic Scholars and Enlightenment Philosophers
This student-faculty collaborative research project focused on the contributions to economic thought of two distinct groups: medieval Arab-Islamic scholars and Enlightenment philosophers. The primary goal of the project was to generate two new chapters to supplement the Evolution of Economic Thought text. It looked to answer the research question, “How did the intellectual activity of medieval Arab-Islamic scholars and Enlightenment philosophers reflect and/or contribute to the development of modern economic thought?” The medieval Arab-Islamic chapter produced findings including a centrality of religion to economic life, the importance of specialization for increased efficiency, and an understanding of just price. Ibn Khaldūn, a prominent scholar of the medieval Arab-Islamic era, recognized a need for the division of labor, as individuals lack the capability of providing sufficient goods on their own to subsist. A holistic approach to thinking and an emphasis on rational methodology and objectivity were major contributions from the research on Enlightenment philosophers. Thomas Hobbes’s social contract theory is a philosophical idea that underlies modern economic theory, discussed at length in the Enlightenment chapter. Both chapters will be accessible online and available for instructors to use separately or in conjunction with existing online chapters as precursors to the main, physical text
Lunar sample analysis
The surface composition of two samples from the highly shocked, glass-coated lunar basalt (12054) and from four glass-coated fragments from the 1-2 mm (14161) fines were examined by X-ray photoemission spectroscopy to determine whether the agglutination process itself is responsible for the difference between their surface and bulk compositions. Auger electron spectroscopy of glass balls from the 15425 and 74001 fines were analyzed to understand the nature, extent, and behavior of volatile phases associated with lunar volcanism. Initial results indicate that (1) volatiles, in the outer few atomic layers sampled, vary considerably from ball to ball; (2) variability over the surface of individual balls is smaller; (3) the dominant volatiles on the balls are S and Zn; and (4) other volatiles commonly observed are P, Cl, and K
Commensurability oscillations due to pinned and drifting orbits in a two-dimensional lateral surface superlattice
We have simulated conduction in a two-dimensional electron gas subject to a
weak two-dimensional periodic potential, . The usual commensurability oscillations in are seen with
alone. An increase of suppresses these oscillations, rather than
introducing the additional oscillations in expected from
previous perturbation theories. We show that this behavior arises from drift of
the guiding center of cyclotron motion along contours of an effective
potential. Periodic modulation in the magnetic field can be treated in the same
way.Comment: 3 pages text, 4 eps figures, revte
Mesoscale assessments of cloud and rainfall over the British Isles
There are no author-identified significant results in this report
Near-optimal protocols in complex nonequilibrium transformations
The development of sophisticated experimental means to control nanoscale
systems has motivated efforts to design driving protocols which minimize the
energy dissipated to the environment. Computational models are a crucial tool
in this practical challenge. We describe a general method for sampling an
ensemble of finite-time, nonequilibrium protocols biased towards a low average
dissipation. We show that this scheme can be carried out very efficiently in
several limiting cases. As an application, we sample the ensemble of
low-dissipation protocols that invert the magnetization of a 2D Ising model and
explore how the diversity of the protocols varies in response to constraints on
the average dissipation. In this example, we find that there is a large set of
protocols with average dissipation close to the optimal value, which we argue
is a general phenomenon.Comment: 6 pages and 3 figures plus 4 pages and 5 figures of supplemental
materia
Evolution from a molecular Rydberg gas to an ultracold plasma in a seeded supersonic expansion of NO
We report the spontaneous formation of a plasma from a gas of cold Rydberg
molecules. Double-resonant laser excitation promotes nitric oxide, cooled to 1
K in a seeded supersonic molecular beam, to single Rydberg states extending as
deep as 80 cm below the lowest ionization threshold. The density of
excited molecules in the illuminated volume is as high as 1 x 10
cm. This population evolves to produce prompt free electrons and a
durable cold plasma of electrons and intact NO ions.Comment: 4 pages (two column) 3 figures; smaller figure files, corrected typo
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