165 research outputs found
Legitimacy of the Constitutional Judge and Theories of Interpretation in the United States
The Legitimacy of the Constitutional Judge and Theories of Interpretation in the United States The paper addresses the sources of legitimacy of a judge exercising the power to declare acts of government invalid on constitutional grounds, and their relationship to theories of interpretation of the constitutional texts
The surprising attractiveness of tearing mode locking in tokamaks
Tearing modes in tokamaks typically rotate while small and then lock at a
fixed location when larger. Research on present-day devices has focused almost
exclusively on stabilisation of rotating modes, as it has been considered
imperative to avoid locked modes. However, in larger devices, such as those
contemplated for tokamak reactors, the locking occurs at a smaller island size,
and the island can be safely stabilised after locking. The stabilisation of
small locked modes can be performed at lower wave power and broader deposition
compared to rotating islands. On large devices, it thus becomes surprisingly
advantageous to allow the mode to grow and lock naturally before stabilising
it. Calculations indicate that the ITER international megaproject would be best
stabilised through this approach.Comment: 6 pages, 4 figure
The exceptional abandonment of metal tools by North American hunter-gatherers, 3000 B.P.
Most prehistoric societies that experimented with copper as a tool raw material eventually abandoned stone as their primary medium for tool making. However, after thousands of years of experimentation with this metal, North American hunter-gatherers abandoned it and returned to the exclusive use of stone. Why? We experimentally confirmed that replica copper tools are inferior to stone ones when each is sourced in the same manner as their archaeological counterparts and subjected to identical tasks. Why, then, did copper consistently lead to more advanced metallurgy in most other areas of the world? We suggest that it was the unusual level of purity in the North American copper sourced by North American groups, and that naturally occurring alloys yielded sufficiently superior tools to encourage entry into the copper-bronze-iron continuum of tool manufacture in other parts of the world
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Inverse Bremsstrahlung Stabilization of Noise in the Generation of Ultra-short Intense Pulses by Backward Raman Amplification
Inverse bremsstrahlung absorption of the pump laser beam in a backward Raman amplifier over the round-trip light transit time through the sub-critical density plasma can more than double the electron temperature of the plasma and produce time-varying axial temperature gradients. The resulting increased Landau damping of the plasma wave and detuning of the resonance can act to stabilize the pump against unwanted amplification of Langmuir noise without disrupting nonlinear amplification of the femtosecond seed pulse. Because the heating rate increases with the charge state Z, only low-Z plasmas (hydrogen, helium, or helium-hydrogen mixtures) will maintain a low enough temperature for efficient operation
Delocalization of electrons in a Random Magnetic Field
Delocalization problem for a two-dimensional non-interacting electron system
is studied under a random magnetic field. With the presence of a random
magnetic field, the Hall conductance carried by each eigenstate can become
nonzero and quantized in units of . Extended states are characterized by
nonzero Hall conductance, and by studying finite-size scaling of the density of
extended states, an insulator-metal phase transition is revealed. The metallic
phase is found at the center of energy band which is separated from the
localized states at the band tails by critical energies . Both
localization exponent and the critical energy are shown to be dependent
on the strength of random magnetic field.Comment: 9 pages, Revtex, 3 figures available upon reques
Fifteen years of clinical liver transplantation
Liver transplantation in humans was first attempted more than 15 yr ago. The 1-yr survival has slowly improved until it has now reached about 50%. In our experience, 46 patients have lived for at least 1 yr, with the longest survival being 9 yr. The high acute mortality in early trials was due in many cases to technical and management errors and to the use of damaged organs. With elimination of such factors, survival increased. Further improvements will depend upon better immunosuppression. Orthotopic liver transplantation (liver replacement) is the preferred operation in most cases, but placement of an extra liver (auxiliary transplantation) may have a role under special circumstances. © 1979
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