On the detection of magnetospheric radio bursts from Uranus and Neptune

Earth, Jupiter, and Saturn are sources of intense but sporadic bursts of electromagnetic radiation or magnetospheric radio bursts (MRB). The similarity of the differential power flux spectra of the MRB from all three planets is examined. The intensity of the MRB is scaled for the solar wind power input into a planetary magnetosphere. The possibility of detecting MRB from Uranus and Neptune is considered

An auroral breakup mechanism

A purely growing electrostatic drift instability driven by the electron temperature gradient at the inner edge of the plasma sheet can grow for large enough values of the temperature gradient. The parallel electric field associated with the instability is localized near the magnetic equator. The growth of the drift instability leads to enhanced whistler noise and increased electron pitch angle diffusion. If the current limit is exceeded in the ionosphere while the parallel electric field of the drift instability exists along the field line, rapid electron precipitation (the auroral breakup) can result

A developmental perspective on alcohol and other drug use during adolescence and the transition to young adulthood

https://deepblue.lib.umich.edu/bitstream/2027.42/137876/1/occ51.pd

<i>Ceramium botryocarpum</i> and <i>C. secundatum</i> re-evaluated

In the British Isles the genus Ceramium is represented by 15 species, divided into to groups. The two groups without cortical spines are (1) fully corticated species and (2) those with ecorticated internodes. Group 1 species are very difficult to distinguish. In particular the key morphological features that discriminate between C. botryocarpum and C. secundatum include the number of periaxial cells and presence of adventitious branching (Maggs and Hommersand, 1993). However, these features may be influenced by the environment. By using various molecular markers, growing cultures in different conditions and crossing experiments we aim to clarify the relationship between the species of group 1.Analysis of the formalin preserved vouchers showed that C. botryocarpum and C. secundatum are morphologically almost identical. They only differ in the number of periaxial cells (6-7 for C. botryocarpum and 7-8 for C. secundatum) and by the more robust, larger thallus of C. secundatum. Culture studies showed that the morphology of Ceramium is highly influenced by the environment. There was crossing with formation of tetrasporophytes between C. botryocarpum and C. secundatum. The phylogenetic analysis with the chloroplast marker (tufA/rpl31) and the mitochondrial marker (cox2-3 spacer, Gabrielsen 2002) clearly demonstrate that C. botryocarpum and C. secundatum are not respectively monophyletic. Analysis of multiple samples and with different techniques confirmed that C. botryocapum Griffiths ex Harvey (1848) is a later synonym of C. secundatum Lyngbye (1819)

Modifications of turbulence and turbulent transport associated with a bias-induced confinement transition in LAPD

Azimuthal flow is driven in the edge of the Large Plasma Device (LAPD) [W. Gekelman, {\itshape et. al}, Rev. Sci. Instr. {\bfseries 62}, 2875 (1991)] through biasing a section of the vacuum vessel relative to the plasma source cathode. As the applied bias exceeds a threshold, a transition in radial particle confinement is observed, evidenced by a dramatic steepening in the density profile, similar to the L- to H-mode transition in toroidal confinement devices. The threshold behavior and dynamic behavior of radial transport is related to flow penetration and the degree of spatial overlap between the flow shear and density gradient profiles. An investigation of the changes in turbulence and turbulent particle transport associated with the confinement transition is presented. Two-dimensional cross-correlation measurements show that the spatial coherence of edge turbulence in LAPD changes significantly with biasing. The azimuthal correlation in the turbulence increases dramatically, while the radial correlation length is little altered. Turbulent amplitude is reduced at the transition, particularly in electric field fluctuations, but the dominant change observed is in the cross-phase between density and electric field fluctuations. The changes in cross-phase lead to a suppression and then apparent reversal of turbulent particle flux as the threshold is exceeded.Comment: 11 pages, 13 figures, accepted for publication in Physics of Plasmas (to appear Jan 2009 issue

Constitutional Law: A Contemporary Approach

Constitutional Law: A Contemporary Approach (2d ed. 2011) is a textbook written by Professors Gregory E. Maggs and Peter J. Smith (both of the George Washington University Law School) and published by West (ISBN-13: 9780314273550). The second edition of the textbook, which is suitable either for a one- or two-semester course, strives to make constitutional law easily teachable and readily accessible for students. The authors have selected the cases very carefully and provided fuller versions of the opinions so that students get a good sense of the Court\u27s reasoning. Text boxes call the students\u27 attention to important aspects of each opinion, and the book is filled with introductions, points for discussion, hypotheticals, and executive summaries. The authors present a diversity of views on every subject, and, reflecting some of their own disagreements, the authors have written point-counterpoint discussions on many disputed questions. Please visit SSRN (http://ssrn.com/abstract=2153213) to access the book parts. The SSRN download includes the preface, table of contents, and the first chapter. This download was prepared and posted with the permission of the publisher

Constitutional Law: A Contemporary Approach

The third edition of the casebook, which is suitable either for a one- or two-semester course, strives to make constitutional law easily teachable and readily accessible for students. The authors have selected the cases very carefully and provided extensive excerpts of the opinions so that students get a good sense of the Court\u27s reasoning. Text boxes call the students\u27 attention to important aspects of each opinion, and the book is filled with introductions, points for discussion, hypotheticals, and executive summaries. The authors present a diversity of views on every subject, and, reflecting some of their own disagreements, the authors have written point-counterpoint discussions on many disputed questions

Modification of turbulent transport with continuous variation of flow shear in the Large Plasma Device

Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) has been achieved using a biasable limiter which has allowed a careful study of the effect of flow shear on pressure-gradient-driven turbulence and transport in LAPD. LAPD rotates spontaneously in the ion diamagnetic direction (IDD); positive limiter bias first reduces, then minimizes (producing a near-zero shear state), and finally reverses the flow into the electron diamagnetic direction (EDD). Degradation of particle confinement is observed in the minimum shearing state and reduction in turbulent particle flux is observed with increasing shearing in both flow directions. Near-complete suppression of turbulent particle flux is observed for shearing rates comparable to the turbulent autocorrelation rate measured in the minimum shear state. Turbulent flux suppression is dominated by amplitude reduction in low-frequency ($<10$kHz) density fluctuations. An increase in fluctuations for the highest shearing states is observed with the emergence of a coherent mode which does not lead to net particle transport. The variations of density fluctuations are fit well with power-laws and compare favorably to simple models of shear suppression of transport.Comment: 10 pages, 5 figures; Submitted to Phys. Rev. Let

Probability distribution of the maximum of a smooth temporal signal

We present an approximate calculation for the distribution of the maximum of a smooth stationary temporal signal X(t). As an application, we compute the persistence exponent associated to the probability that the process remains below a non-zero level M. When X(t) is a Gaussian process, our results are expressed explicitly in terms of the two-time correlation function, f(t)=.Comment: Final version (1 major typo corrected; better introduction). Accepted in Phys. Rev. Let

Energy gaps in quantum first-order mean-field-like transitions: The problems that quantum annealing cannot solve

We study first-order quantum phase transitions in models where the mean-field traitment is exact, and the exponentially fast closure of the energy gap with the system size at the transition. We consider exactly solvable ferromagnetic models, and show that they reduce to the Grover problem in a particular limit. We compute the coefficient in the exponential closure of the gap using an instantonic approach, and discuss the (dire) consequences for quantum annealing.Comment: 6 pages, 3 figure