1,034 research outputs found
Electron turbulence at nanoscale junctions
Electron transport through a nanostructure can be characterized in part using
concepts from classical fluid dynamics. It is thus natural to ask how far the
analogy can be taken, and whether the electron liquid can exhibit nonlinear
dynamical effects such as turbulence. Here we present an ab-initio study of the
electron dynamics in nanojunctions which reveals that the latter indeed
exhibits behavior quite similar to that of a classical fluid. In particular, we
find that a transition from laminar to turbulent flow occurs with increasing
current, corresponding to increasing Reynolds numbers. These results reveal
unexpected features of electron dynamics and shed new light on our
understanding of transport properties of nanoscale systems.Comment: 5 pages, 3 figure
The continuous plankton recorder survey: A long-term, basin-scale oceanic time series
In the 1920s, before the advent of echo sounders, fishery biologists were greatly concerned with assisting the fisherman to locate schools of pelagic fish. One of the approaches they developed was to relate the distribution of the planktonic food organisms to the presence of the schools of predators such as herring (Clupea harengus). The British planktologist, Alister Hardy, who had already carried out extensive studies on the feeding preferences of herring (Hardy, 1926a), initiated a program to examine the fishermen's contention that herring schools avoided 'green', i.e., phytoplankton-rich, water but could be correlated with high concentrations of zooplankton. This practical program was centered on the use of a specially developed instrument, the 'Plankton Indicator', designed to be used by the fisherman to assist in the search for suitable waters. It had limited success in its main aim but, as a collecting device, it embodied several profoundly important features. It was a simple instrument which was robust enough to be deployed and recovered by the crew of commercial vessels (in this case fishing vessels) while they were underway. The Indicator however, was no more than a high speed net which integrated the plankton over the area of sampling, but Hardy had also become interested in describing the patchiness of planktonic populations. He thus developed the Continuous Plankton Recorder (CPR) where he substituted the fixed filter screen of the Indicator by a continually moving length of silk mesh. The screen traversed at constant speed across the path of the incoming water and the trapped organisms were retained in place by sandwiching beneath an additional second mesh screen. Thus, knowing the speed of the towing vessel and the shooting and hauling positions, the spatial patterns of the plankton could be determined. Hardy took the first CPR to the Antarctic where he used it in the Southern Atlantic (Hardy, 1926b) and later deployed it in the North Sea to make some of the earliest contiguous records of plankton patchiness
Foundations of Quantum Decoherence
The conventional interpretation of quantum mechanics, though it permits a
correspondence to classical physics, leaves the exact mechanism of transition
unclear. Though this was only of philosophical importance throughout the
twentieth century, over the past decade new technological developments, such as
quantum computing, require a more thorough understanding of not just the result
of quantum emergence, but also its mechanism. Quantum decoherence theory is the
model that developed out of necessity to deal with the quantum-classical
transition explicitly, and without external observers. In this thesis, we
present a self-contained and rigorously argued full derivation of the master
equation for quantum Brownian motion, one of the key results in quantum
decoherence theory. We accomplish this from a foundational perspective, only
assuming a few basic axioms of quantum mechanics and deriving their
consequences. We then consider a physical example of the master equation and
show that quantum decoherence successfully represents the transition from a
quantum to classical system.Comment: Senior Undergraduate Thesis, The College of Wooster, May 2008, 110
page
Teaching Or Get Off The Lectern: Impediments To Improving International Law Teaching
International law teaching combines the worst aspects of sex and the weather. Everyone thinks they are an expert; they complain about problems but do nothing to improve the situation
The Third United Nations Conference on the Law of the Sea and the New International Economic Order
Assessing the Reality of the Deep Seabed Regime
This Article argues that, in order to be effective, international law must stand in some direct relation to state practice and that the gap between legal prescription and state practice must not be too large or the law will be ineffective. The author examines this gap in relation to the deep seabed provisions of the 1982 United Nations Convention on the Law of the Sea and suggests that, if the gap is not narrowed, the treaty may never enter into force
Post World War II Multilateral Treaty-Making: The Task of the Third United Nations Law of the Sea Conference in Perspective
This Article examines the potential obstacles that must be overcome before the creation of a global law of the sea treaty. The author argues that, even if the Conference proceeds quickly to approve a text, the treaty may never enter into force, because it will be very difficult and time-consuming for the new treaty to be accepted by a majority of the States in the world. The author reviews the various problems likely to be encountered, including signatures not followed by required ratifications, crippling reservations, and States\u27 reluctance to be party to treaties containing dispute settlement clauses. The author examines the precursors to the UNCLOS III treaty and what post-signature barrier might exist to the prompt entry into force of a global law of the sea treaty, and concludes that, given the patterns of the past thirty years, it is likely that a new treaty will never enter into force
The Law of the Sea Conference: Dispute Settlement in Perspective
On March 15, 1976, the Third United Nations Law of the Sea Conference reconvened in New York City. The task of this Conference, drafting a new and comprehensive law of the sea treaty, is enormous. At the very least the new treaty will modify many of the traditional patterns for use and control of hydrospace. There is no doubt that coastal states will achieve the right to exercise control over all resources within 200 nautical miles of their coasts. If this contingency is not implemented by treaty, then it will be reached by unilateral claims to these zones. Agreeing on treaty provisions has been difficult because the issues are of immense value in economic, political, strategic, and psychological terms. Because the issues are of such importance, dispute settlement has been cast as an integral part of any new law of the sea convention.
The dispute settlement issue will be examined in three ways. First, assertions about the importance of dispute settlement and its relationship to the mission of the Conference will be summarized. Secondly, specific proposals for dispute settlement provisions will be discussed. Thirdly, the situation at the Law of the Sea Conference will be compared with other dispute settlement situations
International Law In The Reagan Years: How Much Of An Outlier
But is there reason to believe that the attitude and behavior of the Reagan administration towards international law have been unusually hostile? That fundamental question will be addressed in several ways.
First, one component of President Reagan\u27s foreign policy, aid for the Nicaraguan Contras, will be discussed in some detail. That particular policy has produced perhaps the most sharply drawn, sustained conflict with international law. Second, a much briefer account will be provided about two other Reagan administration encounters with international law. Finally, an attempt will be made to provide some historical perspective to the 1981- 1988 period
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