309 research outputs found
Henri Temianka photographs, professional acquaintances
https://digitalcommons.chapman.edu/temianka_photos/1196/thumbnail.jp
An Approach for Quantitatively Balancing Methylmercury Risk and Omega-3 Benefit in Fish Consumption Advisories
Background: Nearly all fish consumption advisories for methylmercury (MeHg) are based only on risk. There is a need to also address benefits, especially those from polyunsaturated fatty acids (PUFAs), in neurodevelopmental function and cardiovascular health. However, because MeHg and PUFA generally act on these same end points, disentangling risk and benefit is challenging
Persistent Currents and Dissipation in Narrow Bilayer Quantum Hall Bars
Bilayer quantum Hall states support a flow of nearly dissipationless
staggered current which can only decay through collective channels. We study
the dominant finite-temperature dissipation mechanism which in narrow bars is
driven by thermal nucleation of pseudospin solitons. We find the
finite-temperature resistivity, predict the resulting staggered current-voltage
characteristics, and calculate the associated zero-temperature critical
staggered current and gate voltage.Comment: 4 pgs. REVTeX, 3 eps figure
Pseudo-spin canting transition in bilayer quantum Hall ferromagnets: a self-charging capacitor
For sufficiently strong in-plane magnetic field a bilayer quantum
Hall pseudo-ferromagnet is expected to exhibit a soliton lattice. For
sufficiently close layers and large in-plane field, we predict this
incommensurate ``planar'' phase to undergo a reentrant pseudo-spin
canting transition to an incommensurate state , with a finite out-of-plane
pseudo-magnetization component, corresponding to an interlayer charge imbalance
in regions between solitons. At the transition is in the 2d compressible
Ising universality class, and at T=0, the quantum transition is in heretofore
unexplored universality class. The striking experimental signatures are the
universal nonlinear charge-voltage and in-plane field relations, and the
divergence of the differential bilayer capacitance at the transition, resulting
in a bilayer capacitor that spontaneously charges itself, even in the absence
of an applied interlayer voltage.Comment: 4 RevTeX pgs, 1 eps figures, submitted to PR
Reversal of fortune: Macroeconomic policy, International Finance, and Banking in Japan
This essay provides an introduction and overview for a symposium on macroeconomic policy, international finance and banking in Japan. The symposium consists of thirteen papers. Nine of the papers including most of those on macroeconomic policy and international finance appear in this issue. The remaining papers including one on macroeconomic relations within the Asia-Pacific region and three on Japan's banking system will appear in a special section of the next issue of this journal.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47955/1/10368_2005_Article_42.pd
Critical Currents of Ideal Quantum Hall Superfluids
Filling factor bilayer electron systems in the quantum Hall regime
have an excitonic-condensate superfluid ground state when the layer separation
is less than a critical value . On a quantum Hall plateau current
injected and removed through one of the two layers drives a dissipationless
edge current that carries parallel currents, and a dissipationless bulk
supercurrent that carries opposing currents in the two layers. In this paper we
discuss the theory of finite supercurrent bilayer states, both in the presence
and in the absence of symmetry breaking inter-layer hybridization. Solutions to
the microscopic mean-field equations exist at all condensate phase winding
rates for zero and sufficiently weak hybridization strengths. We find, however,
that collective instabilities occur when the supercurrent exceeds a critical
value determined primarily by a competition between direct and exchange
inter-layer Coulomb interactions. The critical current is estimated using a
local stability criterion and varies as when approaches
from below. For large inter-layer hybridization, we find that the
critical current is limited by a soliton instability of microscopic origin.Comment: 18 RevTeX pgs, 21 eps figure
Biofluorescence in Catsharks (Scyliorhinidae): Fundamental Description and Relevance for Elasmobranch Visual Ecology
Biofluorescence has recently been found to be widespread in marine fishes, including sharks. Catsharks, such as the Swell Shark (Cephaloscyllium ventriosum) from the eastern Pacific and the Chain Catshark (Scyliorhinus retifer) from the western Atlantic, are known to exhibit bright green fluorescence. We examined the spectral sensitivity and visual characteristics of these reclusive sharks, while also considering the fluorescent properties of their skin. Spectral absorbance of the photoreceptor cells in these sharks revealed the presence of a single visual pigment in each species. Cephaloscyllium ventriosum exhibited a maximum absorbance of 484 ± 3 nm and an absorbance range at half maximum (λ1/2max) of 440–540 nm, whereas for S. retifer maximum absorbance was 488 ± 3 nm with the same absorbance range. Using the photoreceptor properties derived here, a “shark eye” camera was designed and developed that yielded contrast information on areas where fluorescence is anatomically distributed on the shark, as seen from other sharks’ eyes of these two species. Phylogenetic investigations indicate that biofluorescence has evolved at least three times in cartilaginous fishes. The repeated evolution of biofluorescence in elasmobranchs, coupled with a visual adaptation to detect it; and evidence that biofluorescence creates greater luminosity contrast with the surrounding background, highlights the potential importance of biofluorescence in elasmobranch behavior and biology
Broken-Symmetry States in Quantum Hall Superlattices
We argue that broken-symmetry states with either spatially diagonal or
spatially off-diagonal order are likely in the quantum Hall regime, for clean
multiple quantum well (MQW) systems with small layer separations. We find that
for MQW systems, unlike bilayers, charge order tends to be favored over
spontaneous interlayer coherence. We estimate the size of the interlayer
tunneling amplitude needed to stabilize superlattice Bloch minibands by
comparing the variational energies of interlayer-coherent superlattice miniband
states with those of states with charge order and states with no broken
symmetries. We predict that when coherent miniband ground states are stable,
strong interlayer electronic correlations will strongly enhance the
growth-direction tunneling conductance and promote the possibility of Bloch
oscillations.Comment: 9 pages LaTeX, 4 figures EPS, to be published in PR
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