160,936 research outputs found
Magnets with stabilized conductors
Method fabricates stabilized composite conductor, for use in construction of magnets, using equal amounts of superconducting and metal materials, thus reducing weight, cost and size
Active Gel Model of Amoeboid Cell Motility
We develop a model of amoeboid cell motility based on active gel theory.
Modeling the motile apparatus of a eukaryotic cell as a confined layer of
finite length of poroelastic active gel permeated by a solvent, we first show
that, due to active stress and gel turnover, an initially static and
homogeneous layer can undergo a contractile-type instability to a polarized
moving state in which the rear is enriched in gel polymer. This agrees
qualitatively with motile cells containing an actomyosin-rich uropod at their
rear. We find that the gel layer settles into a steadily moving, inhomogeneous
state at long times, sustained by a balance between contractility and filament
turnover. In addition, our model predicts an optimal value of the
gel-susbstrate adhesion leading to maximum layer speed, in agreement with cell
motility assays. The model may be relevant to motility of cells translocating
in complex, confining environments that can be mimicked experimentally by cell
migration through microchannels.Comment: To appear in New Journal of Physic
Teaching spoken discourse markers explicitly: A comparison of III and PPP
This article reports on mixed methods classroom research carried out at a British university. The study investigates the effectiveness of two different explicit teaching frameworks, Illustration, Interaction, Induction (III) and Present, Practice, Produce (PPP) used to teach the same spoken discourse markers (DMs) to two different groups of Chinese learners and compared to a control group. Univariate analysis of the pre and post tests indicated statistically significant differences between the PPP group and III/control groups in terms of
a higher mean usage of the target DMs in the immediate post test. Qualitative results demonstrated that the PPP group generally found this method to be more useful, which tallied with their better performances in the tests.
Both groups also articulated a desire for a different kind of practice to be used in class, based on rehearsal for real world tasks. This suggests a need to reconceptualise practice within III, PPP or other teaching frameworks
The K Band Luminosity Functions of Galaxies in High Redshift Clusters
K band luminosity functions (LFs) of three, massive, high redshift clusters
of galaxies are presented. The evolution of K*, the characteristic magnitude of
the LF, is consistent with purely passive evolution, and a redshift of forma
tion z = 1.5-2.Comment: 3 pages, to appear in Proceedings of IAU Colloquium 195 - Outskirts
of Galaxy Clusters: intense life in the suburb
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U.S. Customs and Border Protection: Trade Facilitation, Enforcement, and Security
[Excerpt] This report describes and analyzes import policy and CBP’s role in the U.S. import process. (The report does not cover CBP’s role in the U.S. export control system.) The first section of the report describes the three overarching goals of U.S. import policy and the tension among them. Second, the report provides a legislative history of customs laws, followed by an overview of the U.S. import process as it operates today. Third, the import process and CBP’s role in it are discussed. The final section highlights several policy issues that Congress may consider in its oversight role or as part of customs or trade legislation, including measures seeking to provide additional trade facilitation benefits to importers and others enrolled in “trusted trader” programs, to improve enforcement of intellectual property and trade remedy laws, to strengthen cargo scanning practices, and/or to promote modernization of customs data systems, among other issues. A list of trade-related acronyms used in the report is provided in Appendix A
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