ALBERT

Beschreibung: Daily topical application of the aqueous ethanolic extract of the marine sea grass, Thalassia testudinum, on mice skin exposed to UVB radiation resulted in a dose dependent recovery of the skin macroscopic alterations over a 6-day period. Maximal effect (90%) occurred at a dose of 240 μg/cm2, with no additional effects at higher doses. Bioassay-guided fractionation of the plant extract resulted in the isolation of thalassiolin B (1). Topical application of 1 (240 μg/cm2) markedly reduces skin UVB-induced damage. In addition, thalassiolin B scavenged 2,2-diphenyl-2-picrylhydrazyl radical with an EC50=100 μg/ml. These results suggest that thalassiolin B is responsible for the skin regenerating effects of the crude extract of T. testudinum

Beschreibung: Published

Beschreibung: Flavonoids, Thalassiolin B, DPPH scavenged, antioxidant activity, Skin regenerating activity, Thalassia testudinum

Beschreibung: Bioguided fractionation of Agelas cerebrum crude extract resulted in isolation of four bromopyrrole and four bromopyrrole aminoimidazole alkaloids, identified as 5-bromopyrrole-2-carboxylic acid (1), 4-bromopyrrole-2-carboxylic acid (2), 3,4-bromopyrrole-2-carboxylic acid (3), 4,5-bromopyrrole-2-carboxylic acid (4), oroidin (5), bromoageliferin (6), dibromoageliferin (7) and dibromosceptrin (8) on the basis of spectroscopic data analyses (UV, IR, HRMS, 1D and 2D NMR) and comparison with literature data. This is the first report of compounds 2 and 3 in a marine sponge belonging to the Agelas genus and the first evidence of the presence of 1 from a natural source.

Beschreibung: Published

Beschreibung: Agelas cerebrum, bromopyrrole alkaloids, antitumoral, antiprotozoal activity

Beschreibung: La velocidad de descomposición de tres fenólicos, el p-hidroxibenzoico, el protocatecúico y el gálico, los cuales se diferencian en el número de grupos OH, fue investigada en el suelo. Con el aumento de grupos OH aumenta también la velocidad de descomposición microbial. El ácido gálico se descompone más rápido que el protocatecúico y este a su vez más rápido que el phidroxibenzoico.

Beschreibung: The rate of decomposition of the three phenolics, p-hydroxybenzoic acid, protocatechuic acid and gallic acid, whose difference is the amount of OH-groups, was investigated in the soil. With the increase in OH-groups increases the rate of microbial decomposition. Gallic acid decomposes faster than protocatecuic acid and this again faster than p-hydroxybenzoic acid.

Beschreibung: Published

Beschreibung: Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C01027, doi:10.1029/2003JC001877.

Beschreibung: Vertical flow structure and turbulent dissipation in the swash zone are estimated using cross-shore fluid velocities observed on a low-sloped, fine-grained sandy beach [Raubenheimer, 2002] with two stacks of three current meters located about 2, 5, and 8 cm above the bed. The observations are consistent with an approximately logarithmic vertical decay of wave orbital velocities within 5 cm of the bed. The associated friction coefficients are similar in both the uprush and downrush, as in previous laboratory results. Turbulent dissipation rates estimated from velocity spectra increase with decreasing water depth from O(400 cm2/s3) in the inner surf zone to O(1000 cm2/s3) in the swash zone. Friction coefficients in the swash interior estimated with the logarithmic model and independently estimated by assuming that turbulent dissipation is balanced by production from vertical shear of the local mean flow and from wave breaking are between 0.02 and 0.06. These values are similar to the range of friction coefficients (0.02–0.05) recently estimated on impermeable, rough, nonerodible laboratory beaches and to the range of friction coefficients (0.01–0.03) previously estimated from field observations of the motion of the shoreward edge of the swash (run-up).

Beschreibung: This research was supported by ONR and NSF.

Beschreibung: Author Posting. © American Meteorological Society, 2010. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 40 (2010): 2605–2623, doi:10.1175/2010JPO4132.1.

Beschreibung: Steady scale-invariant solutions of a kinetic equation describing the statistics of oceanic internal gravity waves based on wave turbulence theory are investigated. It is shown in the nonrotating scale-invariant limit that the collision integral in the kinetic equation diverges for almost all spectral power-law exponents. These divergences come from resonant interactions with the smallest horizontal wavenumbers and/or the largest horizontal wavenumbers with extreme scale separations. A small domain is identified in which the scale-invariant collision integral converges and numerically find a convergent power-law solution. This numerical solution is close to the Garrett–Munk spectrum. Power-law exponents that potentially permit a balance between the infrared and ultraviolet divergences are investigated. The balanced exponents are generalizations of an exact solution of the scale-invariant kinetic equation, the Pelinovsky–Raevsky spectrum. A small but finite Coriolis parameter representing the effects of rotation is introduced into the kinetic equation to determine solutions over the divergent part of the domain using rigorous asymptotic arguments. This gives rise to the induced diffusion regime. The derivation of the kinetic equation is based on an assumption of weak nonlinearity. Dominance of the nonlocal interactions puts the self-consistency of the kinetic equation at risk. However, these weakly nonlinear stationary states are consistent with much of the observational evidence.

Beschreibung: This research is supported by NSF CMG Grants 0417724, 0417732 and 0417466. YL is also supported by NSF DMS Grant 0807871 and ONR Award N00014-09-1-0515.

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1993

Beschreibung: Breaking waves charge the surface layer of the ocean with small air bubbles which play an important role in air-sea gas transfer and in underwater acoustics near the ocean surface. This work reports on a series of laboratory and field experiments on the measurement on air entrainment by breaking waves. The first part of this thesis addresses the measurement of high volumetric concentrations of air (0.3% to 100% void-fraction) found immediately beneath breaking waves. Instrumentation based on the change of electrical impedance of the bubbly mixture with change in void-fraction is developed. Laboratory measurements are conducted in a wave channel and in a large three-dimensional wave basin. Maps of the evolution of the void-fraction distribution in bubble plumes generated by various size breaking waves are presented. Moments of the void-fraction field are shown to scale with the initially enclosed air volume at breaking and the energy dissipated by breaking. A significant fraction (30 to 50%) of the energy dissipated by breaking is found to be expanded in entraining bubbles against their buoyancy. The results reveal that the bubble plumes experience rapid transformations within the first wave period after the onset of breaking. In particular, the plumes loose 95% of the initially entrained air volume during the fust wave period. Predictions of the low-frequency resonant oscillations of the bubble plumes from measurements of the void-fraction compare well with acoustic measurements. Measurements near the ocean surface show high void-fractions up to 24% immediately beneath breaking waves. These are several orders of magnitude greater than previously reported time-averaged measurements. The second part addresses the measurement of very low void-fractions. Instrumentation based on the propagation velocity of low-frequency acoustic pulses is developed. Simultaneous measurements of the sound-speed (and thus the void-fraction) at several depths are conducted during two field experiments. Time-series of sound-speed and attenuation show dramatic fluctuations over time periods on the order of minutes or less. These are attributed to the formation of bubble plumes or passage of bubble clouds. Frequent occurences of sound-speed anomalies greater than 1 OOrnls and attenuation greater than 30dB/m are observed for moderate wind conditions (8m/s). The signals at various depths are highly correlated and mostly coherent at frequencies below 0.05Hz. The time-averaged (20min) sound-speed profile is found to be significantly more pronounced and shallower than previously reported. Simultaneous measurements at several acoustic frequencies show that the sound-speed is non-dispersive below 20kHz for moderate wind conditions. Bubble size distributions are inferred from the soundspeed and attenuation measurements.

Beschreibung: This research was funded by the Office of Naval Research (Ocean Acoustics and Oceanography) and the National Science Foundation.

Beschreibung: Author Posting. © American Meteorological Society, 2013. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 43 (2013): 2132–2141, doi:10.1175/JPO-D-12-0182.1.

Beschreibung: Repeated occupations of two hydrographic sections in the southwest Pacific basin from the 1990s to 2000s track property changes of Antarctic Bottom Water (AABW). The largest property changes—warming, freshening, increase in total carbon, and decrease in oxygen—are found near the basin’s deep western boundary between 50° and 20°S. The magnitude of the property changes decreases with increasing distance from the western boundary. At the deep western boundary, analysis of the relative importance of AABW (γn 〉 28.1 kg m−3) freshening, heating, or isopycnal heave suggests that the deep ocean stratification change is the result of both warming and freshening processes. The consistent deep ocean changes near the western boundary of the southwest Pacific basin dispel the notion that the deep ocean is quiescent. High-latitude climate variability is being directly transmitted into the deep southwest Pacific basin and the global deep ocean through dynamic deep western boundary currents.

Beschreibung: BMS, SEW, and BT were supported by the Australian Climate Change Science Program, funded jointly by the Department of Climate Change and Energy Efficiency and CSIRO. Funding for AM was provided through NOAA GrantNA110AR4310063.

Beschreibung: 2014-04-01

Beschreibung: Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): C03016, doi:10.1029/2005JC003004.

Beschreibung: Waves have many effects on near-surface dynamics: Breaking waves enhance mixing, waves are associated with a Lagrangian mean drift (the Stokes drift), waves act on the mean flow by creating Langmuir circulations and a return flow opposite to the Stokes drift, and, last but not least, waves modify the atmospheric surface roughness. A realistic ocean model is proposed to embrace all these aspects, focusing on near-surface mixing and surface drift associated with the wind and generated waves. The model is based on the generalized Lagrangian mean that separates the momentum into a wave pseudomomentum and a quasi-Eulerian momentum. A wave spectrum with a reasonably high frequency range is used to compute the Stokes drift. A turbulent closure scheme based on a single evolution equation for the turbulent kinetic energy includes the mixing due to breaking wave effects and wave-turbulence interactions. The roughness length of the closure scheme is adjusted using observations of turbulent kinetic energy near the surface. The model is applied to unstratified and horizontally uniform conditions, showing good agreement with observations of strongly mixed quasi-Eulerian currents near the surface when waves are developed. Model results suggest that a strong surface shear persists in the drift current because of the Stokes drift contribution. In the present model the surface drift only reaches 1.5% of the wind speed. It is argued that stratification and the properties of drifting objects may lead to a supplementary drift as large as 1% of the wind speed.

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1997

Beschreibung: A series of numerical experiments is conducted in order to examine the role of topographic irregularities in generation of subinertial cross-channel barotropic currents and to obtain quantitative estimates of the offshore flow amplitude, its ratio to the magnitude of the alongshore currents and the alongshore correlation scale. A periodic (along the coast) channel with geometry representative of continental margins is considered. Topographic disturbances have multiple alongshore wavenumber contributions, kT, and the amplitude proportional to kT-2 (except one experiment). The motion is forced by spatially uniform and temporally varying alongshore wind stress, which drives the background current along the channel. The background current adjusts to topographic disturbances and, in particular, Barotropic Shelf Waves (BSW) result. That gives rise to the offshore currents. The amplitude of the cross-channel flow is shown to increase with kT in the long wave limit (order of 100 km in the model) and, in contrast, to decrease with kT in the short wave limit (less than 20 km in the model). As a rule, the strongest response is attained on the intermediate scales where lee waves form most efficiently. Hart's {1990} quasi-geostrophic solution provided quantitative parameters to explain the scale dependence and helped to interpret the results of simulations meant to examine sensitivity of the cross-channel flow characteristics to variation of the governing parameters. It is shown that the structure of the resonant wave is established by the combination of spatial properties of the bottom bumps, and by the period and amplitude of the fluctuating background current. On the basis of this analysis, it is demonstrated how the BSW dispersion diagram can be used for diagnostic purposes. The averaged (in time and along the channel) amplitude of subinertial cross-channel currents ranged from negligible values to about 5.5 cm/sec, indicating that, indeed, rather substantial offshore flow can be generated due to the effect of the topographic irregularities. The alongshore correlation scale was no smaller than about 5 km and in a few simulations (for instance, with lee-wave-favourable mean wind included) reached 30 - 50 km.

Beschreibung: This work was supported by the Office of Naval Research, Coastal Science Program, Grant N00014-95-1-0580.

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1998

Beschreibung: Planktonic protozoan grazers have the potential to significantly affect the chemistry of particle-associated trace metals. This is due both to the importance of protists as consumers of bacterial-sized particles, and to the unique low-pH, enzyme-rich microenvironment of the grazer food vacuole. This thesis examines the role of protozoan grazers in the marine geochemistry of strongly hydrolyzed, particle-reactive trace metals, in particular Th and Fe. A series of tracer experiments was carried out in model systems in order to determine the effect of grazer-mediated transformations on the chemical speciation and partitioning of radioisotopes C9Fe, 234Th, 51Cr) associated with prey cells. Results indicate that protozoan grazers are equally able to mobilize intracellular and extracellular trace metals. In some cases, protozoan regeneration of trace metals appears to lead to the formation of metal-organic complexes. Protozoan grazing may generate colloidal material that can scavenge trace metals and, via aggregation, lead to an increase in the metal/organic carbon ratio of aggregated particles. Model system experiments were also conducted in order to determine the effect of grazers on mineral phases, specifically colloidal iron oxide (ferrihydrite). Several independent techniques were employed, including size fractionation ors9Fe-labeled colloids, competitive ligand exchange, and iron-limited diatoms as "probes" for bioavailable Fe. Experimental evidence strongly suggests that protozoan grazing can affect the surface chemistry and increase the dissolution rate of iron oxide phases through phagotrophic ingestion. In further work on protozoan-mediated dissolution of colloidal Fe oxides, a novel tracer technique was developed based on the synthesis of colloidal ferrihydrite impregnated with 133Ba as an inert tracer. This technique was shown to be a sensitive, quantitative indicator for the extent of ferrihydrite dissolution/alteration by a variety of mechanisms, including photochemical reduction and ligand-mediated dissolution. In field experiments using this technique, grazing by naturally occuring protistan assemblages was shown to significantly enhance the dissolution rate of colloidal ferrihydrite over that in non-grazing controls. Laboratory and field results indicate that, when integrated temporally over the entire euphotic zone, protozoan grazing may equal or exceed photoreduction as a pathway for the dissolution of iron oxides.

Beschreibung: This work was financially supported by a Department of Defense ONR-NDSEG Graduate Fellowship, Office ofNaval Research AASERT Award (N00014-94-1-0711), and the National Science Foundation EGB Program (OCE-9523910).

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution October 1987

Beschreibung: A two-layer shallow water equation model is used to investigate the linear stability of a coastal upwelling front. The model features a surface front near a coastal boundary and bottom topography which is an arbitrary function of the cross-shelf coordinate. By combining the various conservation statements for the global properties of the system, a general stability theorem is established which allows the a priori determination of the stability of a coastal upwelling front. Unstable waves are found for the modelled coastal upwelling front. The unstable wave motions are frontally-trapped and dominant in the upper layer. The wave propagates phase in the direction of the basic state flow and the primary energy conversion is via baroclinic instability. The effect of varying the model parameters is presented. Moving the front closer than ~ 2 Rossby radii to the coastal boundary results in a decrease in the growth rate of the fastest growing wave. Increasing the overall vertical shear of the basic state flow, by either decreasing the lower layer depth or increasing the steepness of the interface, results in an increase in the growth of the fastest growing wave. A bottom sloping in the same sense as the interface results in a decrease of the growth rates and alongfront wavenumbers of the unstable waves in the system. Linearized bottom friction is included in the stability model and results in a decrease in the growth rates of the unstable waves by extracting energy from the system. Since the unstable mode is strongest in the upper layer, bottom friction will not stabilize the upwelling front. A comparison between the predictions from the simple two-layer model and observed alongfront variability for three areas of active upwelling is presented. Reasonable agreement is found, suggesting that observed alongfront variability can be interpreted in terms of the instability of a coastal upwelling front.

Beschreibung: This study was supported by the National Science Foundation Grant OCE 84-08563 and the Office of Naval Research Coastal Ocean Sciences Program 10/1984.37.

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution September 1994

Beschreibung: This paper presents a method for estimating the spectra of water wave disturbances on five of the six axes of a stationary, slender body underwater vehicle in an inertia dominated wave force regime, both in head seas and in beam seas. Inertia dominated wave forces are typical of those encountered by a 21 inch diameter, torpedo shaped underwater vehicle operating in coastal waters and sea state 2. Strip theory is used to develop transfer function phase and magnitude between surface water waves and the slender body pitch, heave, and surge forces and moment for the vehicle in head seas, and for pitch, heave, yaw, and sway forces and moments in beam seas. Experiments are conducted which verify this method of transfer function calculation, and demonstrate the effects of vehicle forward motion in the head seas case. Using known sea spectra and linear time invariant systems theory allows for estimation of the water wave disturbance spectra for these forces and moments. Application of sliding control techniques are then developed for the underwater vehicle longitudinal plane equations of motion. Computer simulations are used to demonstrate the dependence of underwater vehicle depth control upon the pitch control, and adaptive pitch control is shown to provide good performance in the presence of substantial parametric uncertainty. Pitch disturbance rejection properties of variations of the sliding controller are investigated. Both single frequency and stochastic disturbances are used, and the stochastic disturbance is developed using the results of the earlier investigation.

Beschreibung: This research was sponsored in part by ONR Contract N00014-90-J-1912.

Beschreibung: Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 39 (2012): L24604, doi:10.1029/2012GL054034.

Beschreibung: Eddies and vortices associated with breaking waves rapidly disperse pollution, nutrients, and terrestrial material along the coast. Although theory and numerical models suggest that vorticity is generated near the ends of a breaking wave crest, this hypothesis has not been tested in the field. Here we report the first observations of wave-generated vertical vorticity (e.g., horizontal eddies), and find that individual short-crested breaking waves generate significant vorticity [O(0.01 s−1)] in the surfzone. Left- and right-handed wave ends generate vorticity of opposite sign, consistent with theory. In contrast to theory, the observed vorticity also increases inside the breaking crest, possibly owing to onshore advection of vorticity generated at previous stages of breaking or from the shape of the breaking region. Short-crested breaking transferred energy from incident waves to lower frequency rotational motions that are a primary mechanism for dispersion near the shoreline.

Beschreibung: Funding was provided by a National Security Science and Engineering Faculty Fellowship, the Office of Naval Research, and a Woods Hole Oceanographic Institution Postdoctoral Fellowship.

Beschreibung: 2013-06-21

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1991

Beschreibung: A model is developed for the prediction of the seismo-acoustic noise spectrum in the microseism peak region (0.1 to 0.7 Hz). The model uses a theory developed by Cato [J. Acoust. Soc. Am., 89 , 1096-1112 (1991)] for an infinite depth ocean in which the surface orbital motion caused by gravity waves may produce acoustic waves at twice the gravity wave frequency. Using directional wave spectra as inputs, acoustic source levels are computed and incorporated into a more realistic environment consisting of a horizontally stratified ocean with an elastic bottom. Noise predictions are made using directional wave spectra obtained from the SWADE surface buoys moored off the coast of Virginia and the SAFARI sound propagation code, with a bottom model derived using wave speeds measured in the EDGE deep seismic reflection survey. The predictions are analyzed for noise level variations with frequency, wave height, wind direction, and receiver depth. These predictions are compared to noise measurements made in ECONOMEX using near-bottom receivers located close to the surface buoys. Good agreement is found between the predictions and observations under a variety of environmental conditions.

Beschreibung: Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 6319–6328, doi:10.1002/2013JC008939.

Beschreibung: Strong and strategic collaborations among experts from academia, federal operational centers, and industry have been forged to create a U.S. IOOS Coastal and Ocean Modeling Testbed (COMT). The COMT mission is to accelerate the transition of scientific and technical advances from the coastal and ocean modeling research community to improved operational ocean products and services. This is achieved via the evaluation of existing technology or the development of new technology depending on the status of technology within the research community. The initial phase of the COMT has addressed three coastal and ocean prediction challenges of great societal importance: estuarine hypoxia, shelf hypoxia, and coastal inundation. A fourth effort concentrated on providing and refining the cyberinfrastructure and cyber tools to support the modeling work and to advance interoperability and community access to the COMT archive. This paper presents an overview of the initiation of the COMT, the findings of each team and a discussion of the role of the COMT in research to operations and its interface with the coastal and ocean modeling community in general. Detailed technical results are presented in the accompanying series of 16 technical papers in this special issue.

Beschreibung: This project was supported by NOAA via the IOOS Office, award NA10NOS0120063 and NA11NOS0120141, and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant OCI- 1053575.

Beschreibung: © The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Coral Reefs 30 (2011): 23-38, doi:10.1007/s00338-010-0705-3.

Beschreibung: Sediment traps are commonly used as standard tools for monitoring “sedimentation” in coral reef environments. In much of the literature where sediment traps were used to measure the effects of “sedimentation” on corals, it is clear from deployment descriptions and interpretations of the resulting data that information derived from sediment traps has frequently been misinterpreted or misapplied. Despite their widespread use in this setting, sediment traps do not provide quantitative information about “sedimentation” on coral surfaces. Traps can provide useful information about the relative magnitude of sediment dynamics if trap deployment standards are used. This conclusion is based first on a brief review of the state of knowledge of sediment trap dynamics, which has primarily focused on traps deployed high above the seabed in relatively deep water, followed by our understanding of near-bed sediment dynamics in shallow-water environments that characterize coral reefs. This overview is followed by the first synthesis of near-bed sediment trap data collected with concurrent hydrodynamic information in coral reef environments. This collective information is utilized to develop nine protocols for using sediment traps in coral reef environments, which focus on trap parameters that researchers can control such as trap height (H), trap mouth diameter (D), the height of the trap mouth above the substrate (z o ), and the spacing between traps. The hydrodynamic behavior of sediment traps and the limitations of data derived from these traps should be forefront when interpreting sediment trap data to infer sediment transport processes in coral reef environments.

Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution November 1990

Beschreibung: One and two layer models are used to study flow over axisymmetric isolated topography. Inviscid or nearly inviscid flow in which non-linear effects have order one importance is considered, and both the effects of β and finite topography are included. A one-layer quasi-geostrophic model is used to find the shape of Taylor columns on both the f-plane and the β-plane in the inviscid limit of the frictional problem. In this limit, the boundary of the Taylor column is a streamline, and the velocity in both directions vanishes on the boundary. The fluid within the Taylor column is stagnant, corresponding to the solution that Ingersoll (1969) found for flow over a right circular cylinder on the f-plane. In this case, the Taylor column is circular. An iterative boundary integral technique is used to find the solutions for flow over a cone on the f-plane. In this case the Taylor column has a tear drop shape. Solutions are also found for flow on the β-plane over a cylinder, and the Taylor column is approximately elliptical for westward flow with the major axis in the x direction, while it is slightly elongated in the y direction for eastward flow. The stagnation point of the Taylor column is located on the edge of the topography for all the solutions found. It was not possible to find solutions for smooth topographic shapes. Steady solutions for flow over a right circular cylinder of finite height are studied when the quasi-geostrophic approximation no longer applies. The solution consists of two parts, one which is similar to the quasi-geostrophic solution and is driven by the potential vorticity anomaly over the topography and the other which is similar to the solution of potential flow around an cylinder and is driven by the matching conditions on the edge of the topography. When the effect of β is large, the transport over the topography is enhanced as the streamlines follow lines of constant background potential vorticity. For eastward flow, the Rossby wave drag can be much larger than predicted from quasi-geostrophic theory. A two-layer model over finite topography using the quasi-geostrophic approximation is developed. The topography is a right circular cylinder which goes all of the way through the lower layer and an order Rossby number amount into the upper layer, so that the quasi-geostrophic approximation can be applied consistently. This geometry allows description of flow in which an isopycnal intersects the topography. The model is valid for a different regime than existing models of steady flow over finite topography in a continuously stratified fluid in which the bottom boundary is an isopycnal surface. The solutions contain the two components that are found in the the barotropic model of flow over finite topography. The model breaks down when the interface goes above the topography which occurs more easily when the stratification is weak. Closed streamlines occur more readily over the topography when the stratification is weak, whereas in traditional quasi-geostrophic theory they occur more readily when the stratification is strong. Near the topography, the interface is depressed to the right and raised to the left (looking downstream). A hierarchy of time-dependent models is used to examine the initial value problem of flow initiation over topography on the f-plane. A modified contour dynamics method is developed that extends the range of problems to which contour dynamics can be applied. The method allows boundary and matching conditions to be applied on a circular boundary. A one-layer quasi-geostrophic model is used to show that more fluid that originates over the topography remains there when the flow is turned on slowly than when it is turned on quickly. Flow over finite topography in a one-layer model shows a variety of different behaviors depending on the topographic height. When the topography has moderate height, two cyclonic eddies are created; when the topography fills up most of the water column, the fluid oscillates on and off the topography as it moves around the topography in a clockwise direction, and none of the fluid is shed downstream. Two quasi-geostrophic stratified models are considered, one in which the topography is small, and the other in which it is finite. In the small topography model, an eddy is shed which is cyclonic, warm-core, and bottom-trapped. In contrast, the shed eddy is cyclonic, cold-core, and surfaceintensified in the finite depth model using the geometry described above.

Beschreibung: This study was supported by the Office of Naval Research Program N00014- 90-J-1839.

Beschreibung: © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 5129–5172, doi:10.1002/jgrc.20376.

Beschreibung: A Gulf of Mexico performance evaluation and comparison of coastal circulation and wave models was executed through harmonic analyses of tidal simulations, hindcasts of Hurricane Ike (2008) and Rita (2005), and a benchmarking study. Three unstructured coastal circulation models (ADCIRC, FVCOM, and SELFE) validated with similar skill on a new common Gulf scale mesh (ULLR) with identical frictional parameterization and forcing for the tidal validation and hurricane hindcasts. Coupled circulation and wave models, SWAN+ADCIRC and WWMII+SELFE, along with FVCOM loosely coupled with SWAN, also validated with similar skill. NOAA's official operational forecast storm surge model (SLOSH) was implemented on local and Gulf scale meshes with the same wind stress and pressure forcing used by the unstructured models for hindcasts of Ike and Rita. SLOSH's local meshes failed to capture regional processes such as Ike's forerunner and the results from the Gulf scale mesh further suggest shortcomings may be due to a combination of poor mesh resolution, missing internal physics such as tides and nonlinear advection, and SLOSH's internal frictional parameterization. In addition, these models were benchmarked to assess and compare execution speed and scalability for a prototypical operational simulation. It was apparent that a higher number of computational cores are needed for the unstructured models to meet similar operational implementation requirements to SLOSH, and that some of them could benefit from improved parallelization and faster execution speed.

Beschreibung: This project was supported by NOAA via the U.S. IOOS Office (award: NA10NOS0120063 and NA11NOS0120141)

Beschreibung: Originally issued as Reference No. 60-20, series later renamed WHOI-.

Beschreibung: Six years of field data plus the conclusions of eight published papers, plus two papers 11 in press", are included in this final report. Wherever possible the writer has attempted to sum up significant unpublished data by the use of illustrations, for example (Plates I through XII and Plates XIII to XVI). All other research, whether fruitful or not is summed up as concisely as possible. The format is outlined in the Contents. It may best be considered in three parts, an Introduction, description of the area and a discussion of technique, for one part. A second part wherein Beach and Coastal Regimen is the topic, this includes profile studies, aerial photography and coastal erosion studies; sediment distribution and wave dynamics is part 3. The studies have led to problems which are unsolved and in a sense the data bearing on these problems is more or less "hanging in air". For example, the most interesting conclusion we derived from the sediment sampling along offshore profiles was that deposition of sediment is confined to a thin strip of sand next to the coast and a mud zone far offshore. These sites of deposition are separated by a zone of erosion or non-deposition. We have carried these ideas rather far and have published a model to explain the mechanics of transport (Miller and Zeigler, in press). Yet, the field sampling is inadequate in spite of supplementary efforts made on two cruises, not a part of this contract, to get enough field data. Consequently, a formal discussion of this problem is in the future and surely that discussion will draw heavily on data which is now inadequate. A second example of a problem in progress, but unsolved concerns inlets. The data is included in this report, but it leads to no conclusions. In keeping with instructions for report requirements for Geography Branch contracts, conclusions of published reports are listed, details are not reported.

Beschreibung: Geography Branch, Office of Naval Research Under Contract Nonr-1254 {00) (NR-388-018)

Beschreibung: Author(s): G. Berner, A. Müller, F. Pfaff, J. Walde, C. Richter, J. Mannhart, S. Thiess, A. Gloskovskii, W. Drube, M. Sing, and R. Claessen We present a detailed study of the electronic structure and band alignment in LaAlO 3 /SrTiO 3 oxide heterostructures by hard x-ray photoelectron spectroscopy. Our spectroscopic measurements find no evidence for the strong potential gradient within the polar LaAlO 3 film predicted by band theory. Due to... [Phys. Rev. B 88, 115111] Published Fri Sep 06, 2013

Beschreibung: Author(s): J. Ignacio Cirac, Spyridon Michalakis, David Pérez-García, and Norbert Schuch We analyze a criterion which guarantees that the ground states of certain many-body systems are stable under perturbations. Specifically, we consider PEPS, which are believed to provide an efficient description, based on local tensors, for the low energy physics arising from local interactions. In o... [Phys. Rev. B 88, 115108] Published Fri Sep 06, 2013

Beschreibung: Author(s): N. Drichko, R. Hackl, and J. Schlueter We compare the photoluminescence spectra of the low-temperature Mott insulator κ -(BEDT–TTF) 2 Cu[N(CN) 2 ]Cl ( T MIT =40 K) with spectra of metallic κ -(BEDT–TTF) 2 Cu[N(CN) 2 ]Br, which is superconducting below T c =11.8 K, in the temperature range between 300 and 20 K. In the Mott insulating state of κ -(BEDT–TT... [Phys. Rev. B 88, 115109] Published Fri Sep 06, 2013

Beschreibung: Author(s): G. Scherrer, M. Hofman, W. Śmigaj, M. Kadic, T.-M. Chang, X. Mélique, D. Lippens, O. Vanbésien, B. Cluzel, F. de Fornel, S. Guenneau, and B. Gralak Ground-plane cloaks, which transform a curved mirror into a flat one, and recently reported at wavelengths ranging from the optical to the visible spectrum, bring the realm of optical illusion a step closer to reality. However, all carpet-cloaking experiments have thus far been carried out in the fa... [Phys. Rev. B 88, 115110] Published Fri Sep 06, 2013

Beschreibung: Author(s): R. L. Stillwell, D. E. Graf, W. A. Coniglio, T. P. Murphy, E. C. Palm, J. H. Park, D. VanGennep, P. Schlottmann, and S. W. Tozer We have observed a massive reconstruction of the Fermi surface of single crystal chromium as a function of high pressure and high magnetic fields caused by the spin-flip transition, with multiple new orbits appearing above 0.93 GPa. In addition, some orbits have field-induced effective masses of ∼0.... [Phys. Rev. B 88, 125119] Published Wed Sep 11, 2013

Beschreibung: Author(s): X. P. Shen, S. D. Chen, Q. Q. Ge, Z. R. Ye, F. Chen, H. C. Xu, S. Y. Tan, X. H. Niu, Q. Fan, B. P. Xie, and D. L. Feng We studied the low-lying electronic structure of the newly discovered iron-platinum-arsenide superconductor, Ca 10 (Pt 4 As 8 )(Fe 2− x Pt x As 2 ) 5 ( T c =22 K) with angle-resolved photoemission spectroscopy. We found that the Pt 4 As 8 layer contributes to a small electronlike Fermi surface, indicative of metallic c... [Phys. Rev. B 88, 115124] Published Fri Sep 13, 2013

Beschreibung: Author(s): F. Nilsson, R. Sakuma, and F. Aryasetiawan In this work we have calculated U from first principles for the early lanthanides (Ce-Gd) using the constrained random phase approximation (cRPA). We compare the static limit of U with experimental estimations from x-ray photoemission spectroscopy (XPS) and bremsstrahlung isochromat spectroscopy (BI... [Phys. Rev. B 88, 125123] Published Fri Sep 13, 2013

Beschreibung: Author(s): Zhen Wang, Yongjian Han, Guang-Can Guo, and Lixin He Recently developed tensor network methods demonstrate great potential for addressing the quantum many-body problem, by constructing variational spaces with polynomially, instead of exponentially, scaled parameters. Constructing such an efficient tensor network, and thus the variational space, is a s... [Phys. Rev. B 88, 121105] Published Tue Sep 17, 2013

Beschreibung: Author(s): Gregory Bulnes Cuetara, Massimiliano Esposito, Gernot Schaller, and Pierre Gaspard A theoretical study is reported of electron transport at finite temperature in a double quantum dot (DQD) capacitively coupled to a quantum point contact (QPC) for the measurement of the DQD charge state. Starting from a Hamiltonian model, a master equation is obtained for the stochastic process tak... [Phys. Rev. B 88, 115134] Published Thu Sep 19, 2013

Beschreibung: Author(s): Kazuma Nakamura, Shiro Sakai, Ryotaro Arita, and Kazuhiko Kuroki We present an ab initio G W calculation to study dynamical effects on an organic compound (TMTSF) 2 PF 6 . Calculated polarized reflectivities reproduce experimental plasma edges at around 0.2 eV for E ∥ b ′ and 1.0 eV for E ∥ a . The low-energy plasmons come out from the low-energy narrow bands energetically ... [Phys. Rev. B 88, 125128] Published Thu Sep 19, 2013

Beschreibung: Author(s): Jiquan Pei, Steve Han, Haijun Liao, and Tao Li The topological entanglement entropy (TEE) of Gutzwiller projected RVB state is studied with Monte Carlo simulation. With tricks to speed up the convergence of TEE, we are able to show that the spin liquid state studied in Zhang et al. [ Phys. Rev. B 84 075128 (2011) ] actually does not support Z 2 t... [Phys. Rev. B 88, 125135] Published Wed Sep 25, 2013

Beschreibung: Author(s): O. Tsyplyatyev and A. J. Schofield Interactions between electrons in one dimension are fully described at low energies by only a few parameters of the Tomonaga-Luttinger model, which is based on linearization of the spectrum. We consider a model of spinless fermions with short-range interaction via the Bethe-Ansatz technique and show... [Phys. Rev. B 88, 115142] Published Thu Sep 26, 2013

Beschreibung: Author(s): J. Maciejko, B. Hsu, S. A. Kivelson, YeJe Park, and S. L. Sondhi The topological physics of quantum Hall states is efficiently encoded in purely topological quantum field theories of the Chern-Simons type. The reliable inclusion of low-energy dynamical properties in a continuum description, however, typically requires proximity to a quantum critical point. We con... [Phys. Rev. B 88, 125137] Published Fri Sep 27, 2013

Beschreibung: Author(s): Eric Cassan, Jean Dellinger, Xavier Le Roux, K. Van Do, Frédérique de Fornel, and Benoît Cluzel The transition between the long-wavelength and the short-wavelength regimes of light propagation in two-dimensional graded photonic crystal is investigated using a hyperspectral near-field scanning microscope. The experiments show an invariant quantity of only 1.78 times the lattice period as the cr... [Phys. Rev. B 88, 125138] Published Fri Sep 27, 2013

Beschreibung: Author(s): Moyuru Kurita, Youhei Yamaji, and Masatoshi Imada We show that a wide class of unconventional quantum criticality emerges when orbital currents cause quantum phase transitions from zero-gap semiconductors such as Dirac fermions to a topological insulator or a Chern insulator. Changes in Fermi-surface topology concomitant with [SU(2) or time-reversa... [Phys. Rev. B 88, 115143] Published Fri Sep 27, 2013

Beschreibung: Author(s): Julius Bonart We study the renormalization group (RG) equations of a pair of spin-boson systems coupled in the z direction with each other. Each spin is coupled to a different bath of harmonic oscillators. We introduce a systematic adiabatic RG, which generalizes the first-order adiabatic renormalization previous... [Phys. Rev. B 88, 125139] Published Fri Sep 27, 2013

Beschreibung: Author(s): Sukhwinder Singh and Guifre Vidal Tensor networks offer a variational formalism to efficiently represent wave functions of extended quantum many-body systems on a lattice. In a tensor network N , the dimension χ of the bond indices that connect its tensors controls the number of variational parameters and associated computational cos... [Phys. Rev. B 88, 115147] Published Mon Sep 30, 2013

Beschreibung: Author(s): Andrew C. Potter and Liang Fu We propose a Josephson junction setup based on a topological insulator (TI) thin film to detect Majorana states that exploits the unique helical and extended nature of the TI surface state. When the magnetic flux through the junction is close to an integer number of flux quanta, Majorana states, pre... [Phys. Rev. B 88, 121109] Published Mon Sep 30, 2013

Beschreibung: Author(s): Chen Fang, Matthew J. Gilbert, Su-Yang Xu, B. Andrei Bernevig, and M. Zahid Hasan We study symmetry-protected features in the quasiparticle interference (QPI) pattern of two-dimensional (2D) systems with mirror symmetries and time-reversal symmetry, around a single static point impurity. We show that, in the Fourier-transformed local density of states (FT-LDOS) ρ ( q , ω ), while the ... [Phys. Rev. B 88, 125141] Published Mon Sep 30, 2013

Beschreibung: Author(s): Jie Wang and Dimitrie Culcer Magnetically doped topological insulators are studied intensively in the search for exotic phenomena such as the quantum anomalous Hall effect. The interplay of electronic and impurity degrees of freedom leads to the Kondo effect, which is an increase in the resistivity at temperatures T 〈 T K (the ... [Phys. Rev. B 88, 125140] Published Mon Sep 30, 2013

Beschreibung: Author(s): S. G. Zybtsev and V. Ya. Pokrovskii We show that rf irradiation drastically increases coherence of the charge-density wave (CDW) depinning and sliding in the electric field for NbS 3 (phase II), TaS 3 , and (TaSe 4 ) 2 I. The effect is observed in the range of the CDW currents at which the fundamental frequencies are well below the frequency... [Phys. Rev. B 88, 125144] Published Mon Sep 30, 2013

Beschreibung: Author(s): S. M. Giampaolo, S. Montangero, F. Dell’Anno, S. De Siena, and F. Illuminati We investigate the scaling of the entanglement spectrum and of the Rényi block entropies and determine its universal aspects in the ground state of critical and noncritical one-dimensional quantum spin models. In all cases, the scaling exhibits an oscillatory behavior that terminates at the factoriz... [Phys. Rev. B 88, 125142] Published Mon Sep 30, 2013

Beschreibung: Author(s): O. A. Tretiakov, K. S. Tikhonov, and V. L. Pokrovsky Spin-orbit interaction in quantum wires leads to a spin resonance at low temperatures, even in the absence of an external dc magnetic field. We study the effect of electron-electron interaction on the resonance. This interaction is strong in quantum wires. We show that the electron-electron interact... [Phys. Rev. B 88, 125143] Published Mon Sep 30, 2013

Beschreibung: Author(s): M.-H. Kim, T. Tanaka, C. T. Ellis, A. Mukherjee, G. Acbas, I. Ohkubo, H. Christen, D. Mandrus, H. Kontani, and J. Cerne The midinfrared anomalous Hall effect (AHE) can provide critical new information for resolving the controversial origins of the dc AHE in Ca x Sr 1− x RuO 3 . The complex Faraday and Kerr angles, as well as the complex Hall conductivity σ x y , are measured in Ca x Sr 1− x RuO 3 films as a function of mid- and near... [Phys. Rev. B 88, 155101] Published Tue Oct 01, 2013

Beschreibung: Author(s): Lars Bonnes, Hannes Pichler, and Andreas M. Läuchli We study the Renyi entropy in the finite-temperature crossover regime of a Hubbard chain using quantum Monte Carlo. The ground-state entropy has characteristic features such as a logarithmic divergence with block size and 2 k F oscillations that are a hallmark of its Luttinger liquid nature. The inter... [Phys. Rev. B 88, 155103] Published Wed Oct 02, 2013

Beschreibung: Author(s): G. Sun, J. Jaramillo, L. Santos, and T. Vekua We study the ground-state phase diagram of two-component fermions loaded in a ladderlike lattice at half filling in the presence of spin-orbit coupling. For repulsive fermions with unidirectional spin-orbit coupling along the legs we identify a Néel state which is separated from rung-singlet and fer... [Phys. Rev. B 88, 165101] Published Wed Oct 02, 2013

Beschreibung: Author(s): Y. Chen, D. L. Bergman, and A. A. Burkov We reconsider the problem of the anomalous Hall effect in ferromagnetic SrRuO 3 , incorporating insights from the recently developed theory of Weyl semimetals. We demonstrate that SrRuO 3 possesses a large number of Weyl nodes, separated in momentum space, in its band structure. While the nodes normall... [Phys. Rev. B 88, 125110] Published Fri Sep 06, 2013

Beschreibung: Author(s): R. Cortés, A. Tejeda, J. Lobo-Checa, C. Didiot, B. Kierren, D. Malterre, J. Merino, F. Flores, E. G. Michel, and A. Mascaraque We take advantage of complementary high-resolution experimental techniques and theoretical tools to get insight into the α -Sn/Ge(111) triangular lattice surface consisting of sp electrons. We report a (3×3) phase, characterized by a charge ordering settled by electronic correlation, which appears be... [Phys. Rev. B 88, 125113] Published Fri Sep 06, 2013

Beschreibung: Author(s): Lucian A. Constantin, Eduardo Fabiano, and Fabio Della Sala Using a reverse-engineering method, we construct a meta-generalized gradient approximation (meta-GGA) angle-averaged exchange-correlation (XC) hole model which has a general applicability. It satisfies known exact hole constraints and can exactly recover the exchange-correlation energy density of an... [Phys. Rev. B 88, 125112] Published Fri Sep 06, 2013

Beschreibung: Author(s): Markus Legner and Titus Neupert We study the entanglement spectrum of noninteracting band insulators, which can be computed from the two-point correlation function, when restricted to one part of the system. In particular, we analyze a type of partitioning of the system that maintains its full translational symmetry, by tracing ov... [Phys. Rev. B 88, 115114] Published Mon Sep 09, 2013

Beschreibung: Author(s): Ana Díaz-Rubio, Jorge Carbonell, Daniel Torrent, and José Sánchez-Dehesa Anisotropic and inhomogeneous metamaterial shells are studied in order to exploit all their resonant mode richness. These multilayer structures are based on a cylindrical distribution of radially dependent constitutive parameters including an inner void cavity. Shell, cavity, and whispering gallery ... [Phys. Rev. B 88, 115118] Published Tue Sep 10, 2013

Beschreibung: Author(s): R. Mahajan, D. M. Ramirez, S. Kachru, and S. Raghu We study the problem of disorder-free metals in the vicinity of a quantum critical point in d =3+1 dimensions. We begin with perturbation theory in the Yukawa coupling between the electrons and undamped bosons (order-parameter fluctuations) and show that the perturbation expansion breaks down below e... [Phys. Rev. B 88, 115116] Published Tue Sep 10, 2013

Beschreibung: Author(s): A. Liam Fitzpatrick, Shamit Kachru, Jared Kaplan, and S. Raghu We study the problem of disorder-free metals near a continuous quantum critical point. We depart from the standard paradigm [ Hertz Phys. Rev. B 14 1165 (1976) and Millis Phys. Rev. B 48 7183 (1993) ] and treat both fermions and bosons (i.e., order parameter fields) on equal footing. We construct ... [Phys. Rev. B 88, 125116] Published Tue Sep 10, 2013

Beschreibung: Author(s): Fabrizio Dolcini and Arianna Montorsi The experimental advances in cold atomic and molecular gases stimulate the investigation of lattice correlated systems beyond the conventional on-site Hubbard approximation, by possibly including multiparticle processes. We study fermionic extended Hubbard models in a one-dimensional lattice with di... [Phys. Rev. B 88, 115115] Published Tue Sep 10, 2013

Beschreibung: Author(s): E. Dobardžić, M. V. Milovanović, and N. Regnault We study the static structure factor of the fractional Chern insulator Laughlin-like state and provide analytical forms for this quantity in the long-distance limit. In the course of this we identify the averaged over the Brillouin zone Fubini-Study metric as the relevant metric in the long-distance... [Phys. Rev. B 88, 115117] Published Tue Sep 10, 2013

Beschreibung: Author(s): Dmitri E. Kharzeev and Ho-Ung Yee Electric circuits involving Weyl semimetals possess unusual properties induced by the quantum anomaly. The chiral magnetic current in a Weyl semimetal subjected to magnetic field modifies the behavior of such circuits in a drastic way. We consider two explicit examples: (i) a circuit involving the “... [Phys. Rev. B 88, 115119] Published Wed Sep 11, 2013

Beschreibung: Author(s): Jian Cui, Luigi Amico, Heng Fan, Mile Gu, Alioscia Hamma, and Vlatko Vedral We consider one-dimensional Hamiltonian systems whose ground states display symmetry-protected topological order. We show that ground states within the topological phase cannot be connected with each other through local operations and classical communication between a bipartition of the system. Our ... [Phys. Rev. B 88, 125117] Published Wed Sep 11, 2013

Beschreibung: Author(s): Shinji Hirose, Yang Liu, and Atsushi Kawamoto Quasi-one-dimensional organic conductors (TMT C F) 2 X have various electric and magnetic properties. Although theoretical and experimental studies have suggested that (TMTTF) 2 Br has the properties of commensurate antiferromagnetism, details of the magnetic structure of this compound are unclear. Two ty... [Phys. Rev. B 88, 125121] Published Thu Sep 12, 2013

Beschreibung: Author(s): K. Matsuda, T. Nagao, Y. Kajihara, M. Inui, K. Tamura, J. Nakamura, K. Kimura, M. Yao, M. Itou, Y. Sakurai, and N. Hiraoka The electron momentum density (EMD) in liquid silicon (Si) has been measured by synchrotron-based Compton scattering. The observed variation in the valence EMD upon melting, reflecting a semiconductor-metal transition of Si, is well explained by the collapse of the Jones zone of crystalline Si. Howe... [Phys. Rev. B 88, 115125] Published Mon Sep 16, 2013

Beschreibung: Author(s): Yichen Huang, C. Karrasch, and J. E. Moore Many low-dimensional materials are well described by integrable one-dimensional models such as the Hubbard model of electrons or the Heisenberg model of spins. However, the small perturbations to these models required to describe real materials are expected to have singular effects on transport quan... [Phys. Rev. B 88, 115126] Published Mon Sep 16, 2013

Beschreibung: Author(s): Jan Kaczmarczyk, Jozef Spałek, Tobias Schickling, and Jörg Bünemann A systematic diagrammatic expansion for Gutzwiller-wave functions (DE-GWF) is formulated and used for the description of superconducting (SC) ground state in the two-dimensional Hubbard model with electron-transfer amplitudes t (and t ′ ) between nearest (and next-nearest) neighbors. The method is num... [Phys. Rev. B 88, 115127] Published Mon Sep 16, 2013

Beschreibung: Author(s): Jonathan M. Buhmann and Manfred Sigrist We study the thermoelectric effect of two-dimensional metals on a square lattice within semiclassical Boltzmann transport theory with particular focus on electron-electron scattering. We compute the electrical conductivity and the Seebeck coefficient as a function of band filling and temperature for... [Phys. Rev. B 88, 115128] Published Mon Sep 16, 2013

Beschreibung: Author(s): M. Wu, E. Benckiser, M. W. Haverkort, A. Frano, Y. Lu, U. Nwankwo, S. Brück, P. Audehm, E. Goering, S. Macke, V. Hinkov, P. Wochner, G. Christiani, S. Heinze, G. Logvenov, H.-U. Habermeier, and B. Keimer A combined analysis of x-ray absorption and resonant reflectivity data was used to obtain the orbital polarization profiles of superlattices composed of four-unit-cell-thick layers of metallic LaNiO 3 and layers of insulating R X O 3 ( R =La, Gd, Dy and X =Al, Ga, Sc), grown on substrates that impose eithe... [Phys. Rev. B 88, 125124] Published Mon Sep 16, 2013

Beschreibung: Author(s): Jack Y. Zhang, Clayton A. Jackson, Santosh Raghavan, Jinwoo Hwang, and Susanne Stemmer Cation displacements, oxygen octahedral tilts, and magnetism of epitaxial, ferrimagnetic, insulating GdTiO 3 films sandwiched between cubic SrTiO 3 layers are studied using scanning transmission electron microscopy and magnetization measurements. With decreasing GdTiO 3 film thickness, structural (GdFe... [Phys. Rev. B 88, 121104] Published Mon Sep 16, 2013

Beschreibung: Author(s): Li Zhang, Merav Dolev, Qi I. Yang, Robert H. Hammond, Bo Zhou, Alexander Palevski, Yulin Chen, and Aharon Kapitulnik Strong spin-orbit coupling in topological insulators results in the ubiquitously observed weak antilocalization feature in their magnetoresistance. Here we present magnetoresistance measurements in ultrathin films of the topological insulator Bi 2 Se 3 and show that in the two-dimensional quantum limit... [Phys. Rev. B 88, 121103] Published Mon Sep 16, 2013

Beschreibung: Author(s): Ebrahim Forati and George W. Hanson A transport-based formulation is used to model three-dimensional objects made of a uniaxial wire medium. The resulting drift-diffusion equation is used to calculate the extinction/scattering cross section of various uniaxial wire medium objects. A comparison is made with measurement and full wave si... [Phys. Rev. B 88, 125125] Published Mon Sep 16, 2013

Beschreibung: Author(s): Yuta Murakami, Philipp Werner, Naoto Tsuji, and Hideo Aoki We study the Holstein-Hubbard model at half filling to explore ordered phases including superconductivity (SC), antiferromagnetism (AF), and charge order (CO) in situations where the electron-electron and electron-phonon interactions are strong (comparable to the electronic bandwidth). The model is ... [Phys. Rev. B 88, 125126] Published Mon Sep 16, 2013

Beschreibung: Author(s): Philip W. Phillips, Brandon W. Langley, and Jimmy A. Hutasoit Since any nontrivial infrared dynamics in strongly correlated electron matter must be controlled by a critical fixed point, we argue that the form of the single-particle propagator can be deduced simply by imposing scale invariance. As a consequence, the unparticle picture proposed by Georgi[14] is ... [Phys. Rev. B 88, 115129] Published Tue Sep 17, 2013

Beschreibung: Author(s): Juan Jiang (姜娟), C. He (贺诚), Y. Zhang (张焱), M. Xu (徐敏), Q. Q. Ge (葛青亲), Z. R. Ye (叶子荣), F. Chen (陈飞), B. P. Xie (谢斌平), and D. L. Feng (封东来) The in-plane resistivity anisotropy has been studied with the Montgomery method on the detwinned parent compound of the iron-based superconductor FeTe. The observed resistivity in the antiferromagnetic (AFM) direction is larger than that in the ferromagnetic (FM) direction, which is different from t... [Phys. Rev. B 88, 115130] Published Tue Sep 17, 2013

Beschreibung: Author(s): Thomas Olsen and Kristian S. Thygesen We assess the performance of a recently proposed renormalized adiabatic local density approximation (rALDA) for ab initio calculations of electronic correlation energies in solids and molecules. The method is an extension of the random phase approximation (RPA) derived from time-dependent density fu... [Phys. Rev. B 88, 115131] Published Wed Sep 18, 2013

Beschreibung: Author(s): Krzysztof Bieniasz and Andrzej M. Oleś We present the exact spectral function for a single oxygen hole with spin opposite to ferromagnetic order within a one-dimensional CuO 3 -like spin chain. We find that local Kondo-like exchange interaction generates five different states in the strong-coupling regime. It stabilizes a spin polaron whic... [Phys. Rev. B 88, 115132] Published Wed Sep 18, 2013

Beschreibung: Author(s): Baoming Tang, Thereza Paiva, Ehsan Khatami, and Marcos Rigol We study finite-temperature properties of strongly interacting fermions in the honeycomb lattice using numerical linked-cluster expansions and determinantal quantum Monte Carlo simulations. We analyze a number of thermodynamic quantities, including the entropy, the specific heat, uniform and stagger... [Phys. Rev. B 88, 125127] Published Wed Sep 18, 2013

Beschreibung: Author(s): Maciej Koch-Janusz, Michael Levin, and Ady Stern Following an earlier construction of exactly soluble lattice models for Abelian fractional topological insulators in two and three dimensions, we construct here an exactly soluble lattice model for a non-Abelian ν =1 quantum Hall state and a non-Abelian topological insulator in two dimensions. We sho... [Phys. Rev. B 88, 115133] Published Thu Sep 19, 2013

Beschreibung: Author(s): Vadim A. Markel and Igor Tsukerman Reflection and refraction of electromagnetic waves by artificial periodic composites (metamaterials) can be accurately modeled by an effective medium theory only if the boundary of the medium is explicitly taken into account and the two effective parameters of the medium (the index of refraction and... [Phys. Rev. B 88, 125131] Published Mon Sep 23, 2013

Beschreibung: Author(s): L. Lajaunie, F. Boucher, R. Dessapt, and P. Moreau Dielectric properties of α-MoO 3 are investigated by a combination of valence electron-energy-loss spectroscopy and ab initio calculation at the random-phase approximation level with the inclusion of local-field effects (LFE). A meticulous comparison between experimental and calculated spectra is per... [Phys. Rev. B 88, 115141] Published Wed Sep 25, 2013

Beschreibung: Author(s): D. Nikolova and A. J. Fisher The dispersion relations for surface plasmon polaritons propagating in the Voigt geometry in a metal-insulator-metal waveguide with a magneto-optically active dielectric medium are derived. The symmetry between the upper and lower interfaces is broken by the introduction of the magnetic field; the b... [Phys. Rev. B 88, 125136] Published Wed Sep 25, 2013

Beschreibung: Author(s): Marco Tavora and Aditi Mitra Results are presented for the dynamics arising due to a sudden quench of a boson interaction parameter with the simultaneous switching on of a commensurate periodic potential, the latter providing a source of nonlinearity that can cause inelastic scattering. A quantum kinetic equation is derived per... [Phys. Rev. B 88, 115144] Published Mon Sep 30, 2013

Beschreibung: Author(s): R. Ang, Y. Miyata, E. Ieki, K. Nakayama, T. Sato, Y. Liu, W. J. Lu, Y. P. Sun, and T. Takahashi We have performed high-resolution angle-resolved photoemission spectroscopy (ARPES) of layered chalcogenide 1 T -TaS 2− x Se x to elucidate the electronic states especially relevant to the occurrence of superconductivity. We found a direct evidence for a Ta-5 d -derived electron pocket associated with the s... [Phys. Rev. B 88, 115145] Published Mon Sep 30, 2013

Beschreibung: Author(s): Andreas Rüegg, Chandrima Mitra, Alexander A. Demkov, and Gregory A. Fiete We theoretically investigate the influence of lattice distortion effects on possible topological phases in (LaNiO 3 ) 2 /(LaAlO 3 ) N heterostructures grown along the [111] direction. At the Hartree-Fock level, topological phases originate from an interaction-generated effective spin-orbit coupling that op... [Phys. Rev. B 88, 115146] Published Mon Sep 30, 2013

Beschreibung: Author(s): R. Ang, K. Nakayama, W.-G. Yin, T. Sato, Hechang Lei, C. Petrovic, and T. Takahashi We have performed angle-resolved photoemission spectroscopy (ARPES) of KFeAgTe 2 , and revealed the absence of band crossing at the Fermi level ( E F ) indicative of the unconventional insulating nature of this material. Comparison of the ARPES-derived band dispersions with the first-principles calculati... [Phys. Rev. B 88, 155102] Published Wed Oct 02, 2013

Beschreibung: Author(s): Li-Yi Zhao, Chu-Shun Tian, Zhao-Qing Zhang, and Xiang-Dong Zhang Very recent experiments have discovered that localized light in strongly absorbing media displays intriguing diffusive phenomena. Here we develop a first-principles theory of light propagation in open media with arbitrary absorption strength and sample length. We show analytically that waves in loca... [Phys. Rev. B 88, 155104] Published Thu Oct 03, 2013

Beschreibung: Author(s): C. Monney, A. Uldry, K. J. Zhou, A. Krzton-Maziopa, E. Pomjakushina, V. N. Strocov, B. Delley, and T. Schmitt We present an electronic structure study of the quasi-one-dimensional chalcogenide BaFe 2 Se 3 using resonant inelastic x-ray scattering (RIXS) at the Fe L 3 edge. In addition to broad spectral contributions from fluorescence, sharp peaks are seen at the low-energy end of the spectra, suggesting the coe... [Phys. Rev. B 88, 165103] Published Thu Oct 03, 2013

Beschreibung: Author(s): Loren Greenman, Heather D. Whitley, and K. Birgitta Whaley We present density functional theory calculations of phosphorus dopants in bulk silicon and of several properties relating to their use as spin qubits for quantum computation. Rather than a mixed pseudopotential or a Heitler-London approach, we have used an explicit treatment for the phosphorus dono... [Phys. Rev. B 88, 165102] Published Thu Oct 03, 2013

Beschreibung: Author(s): Lance J. Nelson, Vidvuds Ozoliņš, C. Shane Reese, Fei Zhou, and Gus L. W. Hart Long-standing challenges in cluster expansion (CE) construction include choosing how to truncate the expansion and which crystal structures to use for training. Compressive sensing (CS), which is emerging as a powerful tool for model construction in physics, provides a mathematically rigorous framew... [Phys. Rev. B 88, 155105] Published Thu Oct 03, 2013

Beschreibung: Author(s): Laura Messio, Philippe Corboz, and Frédéric Mila We study a quantum version of the three-state Potts model that includes as special cases the effective models of bosons and fermions on the square lattice in the Mott-insulating limit. It can be viewed as a model of quantum permutations with amplitudes J ∥ and J ⊥ for identical and different colors, r... [Phys. Rev. B 88, 155106] Published Fri Oct 04, 2013

Beschreibung: Author(s): Yan Liu, Sébastien Guenneau, and Boris Gralak Effective properties of periodic structures are investigated at all frequencies. It is shown that a simple dielectric multilayer with arbitrary low contrast can display artificial magnetoelectric coupling and magnetism. Effective parameters, as functions of the complex frequency, possess all the ana... [Phys. Rev. B 88, 165104] Published Fri Oct 04, 2013

Beschreibung: Author(s): Kalani Hettiarachchilage, Valéry G. Rousseau, Ka-Ming Tam, Mark Jarrell, and Juana Moreno We study a doped two-dimensional bosonic Hubbard model with two hard-core species using quantum Monte Carlo simulations. With doping we find five distinct phases, including a normal liquid at higher temperature, an antiferromagnetically ordered Mott insulator, a region of coexistent antiferromagneti... [Phys. Rev. B 88, 161101] Published Fri Oct 04, 2013

Beschreibung: Author(s): E. V. Gorbar, V. A. Miransky, and I. A. Shovkovy We study the phase diagram of a Dirac semimetal in a magnetic field at a nonzero charge density. It is shown that there exists a critical value of the chemical potential at which a first-order phase transition takes place. At subcritical values of the chemical potential the ground state is a gapped ... [Phys. Rev. B 88, 165105] Published Fri Oct 04, 2013