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Climate and Land-Use Controls on Surface Water Diversions in the Central Valley, California
California’s Central Valley (CV) is one of the most productive agricultural regions in the world, enabled by the conjunctive use of surface water and groundwater. We investigated variations in the CV’s managed surface water diversions relative to climate variability. Using a historical record (1979−2010) of diversions from 531 sites, we found diversions are largest in the wetter Sacramento basin to the north, but most variable in the drier Tulare basin to the south. A rotated empirical orthogonal function (REOF) analysis finds 72% of the variance of diversions is captured by the first three REOFs. The leading REOF (35% of variance) exhibited strong positive loadings in the Tulare basin, and the corresponding principal component time-series (RPC1) was strongly correlated (ρ > 0.9) with contemporaneous hydrologic variability. This pattern indicates larger than average diversions in the south, with neutral or slightly less than average diversions to the north during wet years, with the opposite true for dry years. The second and third REOFs (20% and 17% of variance, respectively), were strongest in the Sacramento basin and San Francisco Bay−Delta. RPC2 and RPC3 were associated with variations in agricultural- and municipal-bound diversions, respectively. RPC2 and RPC3 were also moderately correlated with 7-year cumulative precipitation based on lagged correlation analysis, indicating that diversions in the north and central portions of the CV respond to longer-term hydrologic variations. The results illustrate a dichotomy of regimes wherein diversions in the more arid Tulare are governed by year-to-year hydrologic variability, while those in wetter northern basins reflect land-use patterns and low-frequency hydrologic variations
Using HINODE/Extreme-Ultraviolet Imaging Spectrometer to confirm a seismologically inferred coronal temperature
The Extreme-Ultraviolet Imaging Spectrometer on board the HINODE satellite is used to examine the loop system described in Marsh et al. (2009) by applying spectroscopic diagnostic methods. A simple isothermal mapping algorithm is applied to determine where the assumption of isothermal plasma may be valid, and the emission measure locii technique is used to determine the temperature profile along the base of the loop system. It is found that, along the base, the loop has a uniform temperature profile with a mean temperature of 0.89 +- 0.09 MK which is in agreement with the temperature determined seismologically in Marsh et al. (2009), using observations interpreted as the slow magnetoacoustic mode. The results further strengthen the slow mode interpretation, propagation at a uniform sound speed, and the analysis method applied in Marsh et al. (2009). It is found that it is not possible to discriminate between the slow mode phase speed and the sound speed within the precision of the present observations
Holiness and Hopefulness: The Monastic and Lay Audiences of Abbo of Fleury's Passio Sancti Eadmundi and Ælfric of Eynsham's Life of St. Edmund, King and Martyr
Einstein and Jordan frames reconciled: a frame-invariant approach to scalar-tensor cosmology
Scalar-Tensor theories of gravity can be formulated in different frames, most
notably, the Einstein and the Jordan one. While some debate still persists in
the literature on the physical status of the different frames, a frame
transformation in Scalar-Tensor theories amounts to a local redefinition of the
metric, and then should not affect physical results. We analyze the issue in a
cosmological context. In particular, we define all the relevant observables
(redshift, distances, cross-sections, ...) in terms of frame-independent
quantities. Then, we give a frame-independent formulation of the Boltzmann
equation, and outline its use in relevant examples such as particle freeze-out
and the evolution of the CMB photon distribution function. Finally, we derive
the gravitational equations for the frame-independent quantities at first order
in perturbation theory. From a practical point of view, the present approach
allows the simultaneous implementation of the good aspects of the two frames in
a clear and straightforward way.Comment: 15 pages, matches version to be published on Phys. Rev.
Phase-resolved far-ultraviolet HST spectroscopy of the peculiar magnetic white dwarf RE J0317-853
We present phase resolved FUV HST FOS spectra of the rapidly rotating, highly
magnetic white dwarf RE J0317-853. Using these data, we construct a new model
for the magnetic field morphology across the stellar surface. From an expansion
into spherical harmonics, we find the range of magnetic field strengths present
is 180-800MG. For the first time we could identify an absorption feature
present at certain phases at 1160A as a ``forbidden'' 1s_0 -> 2s_0 component,
due to the combined presence of an electric and magnetic field.Comment: 15 pages including 4 figures. Accepted for publication in ApJ Letter
Fast quantum algorithm for numerical gradient estimation
Given a blackbox for f, a smooth real scalar function of d real variables,
one wants to estimate the gradient of f at a given point with n bits of
precision. On a classical computer this requires a minimum of d+1 blackbox
queries, whereas on a quantum computer it requires only one query regardless of
d. The number of bits of precision to which f must be evaluated matches the
classical requirement in the limit of large n.Comment: additional references and minor clarifications and corrections to
version
Role of interactions in ferrofluid thermal ratchets
Orientational fluctuations of colloidal particles with magnetic moments may
be rectified with the help of external magnetic fields with suitably chosen
time dependence. As a result a noise-driven rotation of particles occurs giving
rise to a macroscopic torque per volume of the carrier liquid. We investigate
the influence of mutual interactions between the particles on this ratchet
effect by studying a model system with mean-field interactions. The stochastic
dynamics may be described by a nonlinear Fokker-Planck equation for the
collective orientation of the particles which we solve approximately by using
the effective field method. We determine an interval for the ratio between
coupling strength and noise intensity for which a self-sustained rectification
of fluctuations becomes possible. The ratchet effect then operates under
conditions for which it were impossible in the absence of interactions.Comment: 18 pages, 10 figure
Canine Insulinoma
Hypoglycemia in a dog due to an insulinoma was first reported in the literature in 1927. Although there have been many reported cases since that time, it is still considered to be a fairly rare condition by most authors. Its frequency, however, is probably much greater than the literature would lead one to believe, as the vast majority of cases go unreported or unrecognized. The Iowa State University Teaching Hospital alone diagnoses three or four cases each year, which is a substantial number in light of the fact that functional beta cell tumors have been reported in only 45 dogs
Quantum Discord and Quantum Computing - An Appraisal
We discuss models of computing that are beyond classical. The primary
motivation is to unearth the cause of nonclassical advantages in computation.
Completeness results from computational complexity theory lead to the
identification of very disparate problems, and offer a kaleidoscopic view into
the realm of quantum enhancements in computation. Emphasis is placed on the
`power of one qubit' model, and the boundary between quantum and classical
correlations as delineated by quantum discord. A recent result by Eastin on the
role of this boundary in the efficient classical simulation of quantum
computation is discussed. Perceived drawbacks in the interpretation of quantum
discord as a relevant certificate of quantum enhancements are addressed.Comment: To be published in the Special Issue of the International Journal of
Quantum Information on "Quantum Correlations: entanglement and beyond." 11
pages, 4 figure
Single-Molecule Junction Conductance through Diaminoacenes
The study of electron transport through single molecules is essential to the
development of molecular electronics. Indeed, trends in electronic conductance
through organic nanowires have emerged with the increasing reliability of
electron transport measurements at the single-molecule level. Experimental and
theoretical work has shown that tunneling distance, HOMO-LUMO gap and molecular
conformation influence electron transport in both saturated and pi-conjugated
nanowires. However, there is relatively little experimental data on electron
transport through fused aromatic rings. Here we show using diaminoacenes that
conductivity depends not only on the number of fused aromatic rings in the
molecule, which defines the molecular HOMO-LUMO gap, but also on the position
of the amino groups on the rings. Specifically, we find that conductance is
highest with minimal disruption of aromaticity in fused aromatic nanowires.Comment: 2 pages, 3 figure
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