bluuebunny/crossref_metadata_2025 huggingface dataset:
A Neural Region of Abstract Working Memory
Authors: Cowan Nelson , Li Dawei , Moffitt Amanda , Becker Theresa M. , Martin Elizabeth A. , Saults J. Scott , Christ Shawn E.
Published: January 2011

Over 350 years ago, Descartes proposed that the neural basis of consciousness must be a brain region in which sensory inputs are combined. Using fMRI, we identified at least one such area for working memory, the limited information held in mind, described by William James as the trailing edge of consciousness. Specifically, a region in the left intraparietal sulcus was found to demonstrate load-dependent activity for either visual stimuli (colored squares) or a combination of visual and auditory stimuli (spoken letters). This result was replicated across two experiments with different participants and methods. The results suggest that this brain region, previously well known for working memory of visually presented materials, actually holds or refers to information from more than one modality.
Double Dissociation of Dopamine Genes and Timing in Humans
Authors: Wiener Martin , Lohoff Falk W. , Coslett H. Branch
Published: January 2011

A number of lines of evidence implicate dopamine in timing [Rammsayer, T. H. Neuropharmacological approaches to human timing. In S. Grondin (Ed.), Psychology of time (pp. 295–320). Bingley, UK: Emerald, 2008; Meck, W. H. Neuropharmacology of timing and time perception. Brain Research, Cognitive Brain Research, 3, 227–242, 1996]. Two human genetic polymorphisms are known to modulate dopaminergic activity. DRD2/ANKK1-Taq1a is a D2 receptor polymorphism associated with decreased D2 density in the striatum [Jönsson, E. G., Nothen, M. M., Grunhage, F., Farde, L., Nakashima, Y., Propping, P., et al. Polymorphisms in the dopamine D2 receptor gene and their relationships to striatal dopamine receptor density of healthy volunteers. Molecular Psychiatry, 4, 290–296, 1999]; COMT Val158Met is a functional polymorphism associated with increased activity of the COMT enzyme such that catabolism of synaptic dopamine is greater in pFC [Meyer-Lindenberg, A., Kohn, P. D., Kolachana, B., Kippenhan, S., McInerney-Leo, A., Nussbaum, R., et al. Midbrain dopamine and prefrontal function in humans: Interaction and modulation by COMT genotype. Nature Neuroscience, 8, 594–596, 2005]. To investigate the role of dopamine in timing, we genotyped 65 individuals for DRD2/ANKK1-Taq1a, COMT Val158Met, and a third polymorphism, BDNF Val66Met, a functional polymorphism affecting the expression of brain-derived neurotrophic factor [Egan, M. F., Kojima, M., Callicott, J. H., Goldberg, T. E., Kolachana, B. S., Bertolino, A., et al. The BDNF val66met polymorphism affects activity-dependent secretion of BDNF and human memory and hippocampal function. Cell, 112, 257–269, 2003]. Subjects were tested on a temporal discrimination task with sub- and supra-second intervals (500- and 2000-msec standards) as well as a spontaneous motor tempo task. We found a double dissociation for temporal discrimination: the DRD2/ANKK1-Taq1a polymorphism (A1+ allele) was associated with significantly greater variability for the 500-msec duration only, whereas the COMT Val158Met polymorphism (Val/Val homozygotes) was associated with significantly greater variability for the 2000-msec duration only. No differences were detected for the BDNF Vall66Met variant. Additionally, the DRD2/ANKK1-Taq1a polymorphism was associated with a significantly slower preferred motor tempo. These data provide a potential biological basis for the distinctions between sub- and supra-second timing and suggest that BG are integral for the former whereas pFC is implicated in the latter.
Evolution of Multiscale Vortices in the Development of Hurricane Dolly (2008)
Authors: Fang Juan , Zhang Fuqing
Published: January 2011

As a follow-up to a previously published article on the initial development and genesis of Hurricane Dolly (2008), this study further examines the evolution of, and interactions among, multiscale vortices ranging from the system-scale main vortex (L > 150 km) to the intermediate-scale cloud clusters (50 km < L < 150 km) and individual vorticity-rich convective cells (L < 50 km). It is found that there are apparent self-similarities among these vortices at different scales, each of which may undergo several cycles of alternating accumulation and release of convective available potential energy. Enhanced surface fluxes below individual cyclonic vortices at each scale contribute to the sustainment and reinvigoration of moist convection that in turn contributes to the maintenance and upscale growth of these vortices.

Spectral analysis of horizontal divergence and relative vorticity further suggests that the cloud-cluster-scale and system-scale vortices are predominantly balanced while the individual convective vortices are largely unbalanced. The vorticity and energy produced by these individual vorticity-rich convective cells first saturate at convective scales that are subsequently transferred to larger scales. The sum of the diabatic heating released from these convective cells may be regarded as a persistent forcing on the quasi-balanced system-scale vortex. The secondary circulation induced by such forcing converges the cluster- and convective-scale vorticity anomalies into the storm center region. Convergence and projections of the smaller-scale vorticity to the larger scales eventually produce the spinup of the system-scale vortex. Meanwhile, convectively induced negative vorticity anomalies also converge toward the storm center, which are weaker and shorter lived, and thus are absorbed rather than expelled.
An Objective Algorithm for Detecting and Tracking Tropical Cloud Clusters: Implications for Tropical Cyclogenesis Prediction
Authors: Hennon Christopher C. , Helms Charles N. , Knapp Kenneth R. , Bowen Amanda R.
Published: January 2011

An algorithm to detect and track global tropical cloud clusters (TCCs) is presented. TCCs are organized large areas of convection that form over warm tropical waters. TCCs are important because they are the “seedlings” that can evolve into tropical cyclones. A TCC satisfies the necessary condition of a “preexisting disturbance,” which provides the required latent heat release to drive the development of tropical cyclone circulations. The operational prediction of tropical cyclogenesis is poor because of weaknesses in the observational network and numerical models; thus, past studies have focused on identifying differences between “developing” (evolving into a tropical cyclone) and “nondeveloping” (failing to do so) TCCs in the global analysis fields to produce statistical forecasts of these events.

The algorithm presented here has been used to create a global dataset of all TCCs that formed from 1980 to 2008. Capitalizing on a global, Gridded Satellite (GridSat) infrared (IR) dataset, areas of persistent, intense convection are identified by analyzing characteristics of the IR brightness temperature (Tb) fields. Identified TCCs are tracked as they move around their ocean basin (or cross into others); variables such as TCC size, location, convective intensity, cloud-top height, development status (i.e., developing or nondeveloping), and a movement vector are recorded in Network Common Data Form (NetCDF). The algorithm can be adapted to near-real-time tracking of TCCs, which could be of great benefit to the tropical cyclone forecast community.
Spatiotemporal Behavior of the TIGGE Medium-Range Ensemble Forecasts
Authors: Kipling Zak , Primo Cristina , Charlton-Perez Andrew
Published: January 2011

Using the recently developed mean–variance of logarithms (MVL) diagram, together with The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) archive of medium-range ensemble forecasts from nine different centers, an analysis is presented of the spatiotemporal dynamics of their perturbations, showing how the differences between models and perturbation techniques can explain the shape of their characteristic MVL curves. In particular, a divide is seen between ensembles based on singular vectors or empirical orthogonal functions, and those based on bred vector, ensemble transform with rescaling, or ensemble Kalman filter techniques.

Consideration is also given to the use of the MVL diagram to compare the growth of perturbations within the ensemble with the growth of the forecast error, showing that there is a much closer correspondence for some models than others. Finally, the use of the MVL technique to assist in selecting models for inclusion in a multimodel ensemble is discussed, and an experiment suggested to test its potential in this context.
Improving Probabilistic Ensemble Forecasts of Convection through the Application of QPF–POP Relationships
Authors: Schaffer Christopher J. , Gallus William A. , Segal Moti
Published: January 2011

Four new approaches of postprocessing quantitative precipitation forecasts (QPFs) from model ensemble output were used to generate probability of precipitation (POP) tables in order to develop a forecasting method that could outperform a traditional method that relies upon calibration of POP forecasts derived using equal weighting of ensemble members. Early warm season 10-member ensemble output from the NOAA Hazardous Weather Testbed Spring Experiments was used, with 29 cases serving as a training set to create the POP tables and 20 cases used as a test set. The new approaches use QPF–POP relationships based on two properties termed precipitation amount characteristic (PAC) and ensemble member agreement. Exploratory results are presented for 20-km grid spacing and selectively for 4-km grid spacing. In the first approach, POPs were based on a binned PAC and the number of ensemble members with 6-h precipitation accumulations greater than given thresholds. In a second approach, a neighborhood method was used to find the number of points in a given neighborhood area around each of the domain grid points with precipitation amounts greater than a given threshold, while also considering the binned PAC representative of the neighborhood. A third approach synthesized the previous methods and led to an increase in skill relative to the individual methods, and a fourth approach using a combination of methods produced forecasts with even greater skill. All of the forecasts from the four approaches were improved statistically significantly compared to the calibrated traditional method’s forecasts at 20-km grid spacing. The second approach on its own showed skill comparable to that obtained by a traditional calibrated 10-member ensemble, so adopting this approach alone could potentially save computer resources that could then be used for model refinements, only sacrificing the increased skill that could have been obtained by using the fourth approach.
Improving High-Resolution Model Forecasts of Downslope Winds in the Las Vegas Valley
Authors: Pattantyus Andre K. , Chiao Sen , Czyzyk Stanley
Published: January 2011

Numerical simulations for severe downslope winds as well as trapped lee waves in Nevada’s Las Vegas Valley were performed in this study. The goal of this study was to improve model forecasts of downslope-wind-event intensities. This was measured by assessing different planetary boundary layer (PBL) schemes in the mountain–valley region. The Weather Research and Forecasting Model was adopted for this research. The numerical experiments were constructed using two nested domains, with 4- and 1-km grid resolution. The working hypothesis was that the occurrence of low-level wind shear and surface gustiness in the Las Vegas Valley was guided by the inversion layer in the valley. The choice of boundary layer scheme and model vertical resolution will influence inversion-layer height and consequently result in significant differences in surface wind and temperature forecast error below some near-surface height. Simulations of severe downslope wind events on 15 April 2008 and on 4 October 2009 were conducted. Statistical analyses of model results from three different PBL schemes and different vertical resolutions were performed. The results from the domain with 1-km grid spacing demonstrated remarkable detail of the severe downslope winds associated with low-level wind shear and surface gustiness in the Las Vegas Valley. The simulation results demonstrated that model vertical resolution was primarily responsible for the detail of the lower-level wind and temperature structures. The inverse Froude number and Froude number are two indices that may be included as the forecasting guidance for downslope winds, lee waves, and rotors for the Las Vegas Valley.
A Statistical Model of Tropical Cyclone Tracks in the Western North Pacific with ENSO-Dependent Cyclogenesis
Authors: Yonekura Emmi , Hall Timothy M.
Published: January 2011

A new statistical model for western North Pacific Ocean tropical cyclone genesis and tracks is developed and applied to estimate regionally resolved tropical cyclone landfall rates along the coasts of the Asian mainland, Japan, and the Philippines. The model is constructed on International Best Track Archive for Climate Stewardship (IBTrACS) 1945–2007 historical data for the western North Pacific. The model is evaluated in several ways, including comparing the stochastic spread in simulated landfall rates with historic landfall rates. Although certain biases have been detected, overall the model performs well on the diagnostic tests, for example, reproducing well the geographic distribution of landfall rates. Western North Pacific cyclogenesis is influenced by El Niño–Southern Oscillation (ENSO). This dependence is incorporated in the model’s genesis component to project the ENSO-genesis dependence onto landfall rates. There is a pronounced shift southeastward in cyclogenesis and a small but significant reduction in basinwide annual counts with increasing ENSO index value. On almost all regions of coast, landfall rates are significantly higher in a negative ENSO state (La Niña).
Blowing Snow on Arctic Sea Ice: Results from an Improved Sea Ice–Snow–Blowing Snow Coupled System
Authors: Chung Yi-Ching , Bélair Stéphane , Mailhot Jocelyn
Published: January 2011

A one-dimensional (1D) version of a blowing snow model, called PIEKTUK-D, has been incorporated into a snow–sea ice coupled system. Blowing snow results in sublimation of approximately 12 mm of snow water equivalent (SWE), which is equal to approximately 6% of the annual precipitation over 324 days from 1997 to 1998. This effect leads to an average decrease of 9 cm in snow depth for an 11-month simulation of the Surface Heat Budget of the Arctic Ocean (SHEBA) dataset (from 31 October 1997 to 1 October 1998). Inclusion of blowing snow has a significant impact on snow evolution between February and June, during which it is responsible for a decrease in snow depth error by about 30%. Between November and January, however, other factors such as regional surface topography or horizontal wind transport may have had a greater influence on the evolution of the snowpack and sea ice. During these few months the new system does not perform as well, with a snow depth percentage error of 39%—much larger than the 12% error found between February and June. The results also indicate a slight increase of 4 cm on average for ice thickness, and a decrease of 0.4 K for the temperature at the snow–ice interface. One of the main effects of blowing snow is to shorten the duration of snow cover above sea ice by approximately 4 days and to lead to earlier ice melt by approximately 6 days. Blowing snow also has a very small impact on internal characteristics of the snowpack, such as grain size and density, leading to a weaker snowpack.
Modeling Snow–Canopy Processes on an Idealized Mountain
Authors: Strasser Ulrich , Warscher Michael , Liston Glen E.
Published: January 2011

Snow interception in a coniferous forest canopy is an important hydrological feature, producing complex mass and energy exchanges with the surrounding atmosphere and the snowpack below. Subcanopy snowpack accumulation and ablation depends on the effects of canopy architecture on meteorological conditions and on interception storage by stems, branches, and needles. Mountain forests are primarily composed of evergreen conifer species that retain their needles throughout the year and hence intercept snow efficiently during winter. Canopy-intercepted snow can melt, fall to the ground, and/or sublimate into the air masses above and within the canopy. To improve the understanding of snow–canopy interception processes and the associated influences on the snowpack below, a series of model experiments using a detailed, physically based snow–canopy and snowpack evolution model [Alpine Multiscale Numerical Distributed Simulation Engine (AMUNDSEN)] driven with observed meteorological forcing was conducted. A cone-shaped idealized mountain covered with a geometrically regular pattern of coniferous forest stands and clearings was constructed. The model was applied for three winter seasons with different snowfall intensities and distributions. Results show the effects of snow–canopy processes and interactions on the pattern of ground snow cover, its duration, and the amount of meltwater release, in addition to showing under what conditions the protective effect of a forest canopy overbalances the reduced accumulation of snow on the ground. The simulations show considerable amounts of canopy-intercepted snowfall can sublimate, leading to reduced snow accumulation beneath the forest canopy. In addition, the canopy produces a shadowing effect beneath the trees that leads to reduced radiative energy reaching the ground, reduced below-canopy snowmelt rates, and increased snow-cover duration relative to nonforested areas. During snow-rich winters, the shadowing effect of the canopy dominates and snow lasts longer inside the forest than in the open, but during winters with little snow, snow sublimation losses dominate and snow lasts longer in the open areas than inside the forest. Because of the strong solar radiation influence on snowmelt rates, the details of these relationships vary for northern and southern radiation exposures and time of year. In early and high winter, the radiation protection effect of shadowing by the canopy is small. If little snow is available, an intermittent melt out of the snow cover inside the forest can occur. In late winter and spring, the shadowing effect becomes more efficient and snowmelt is delayed relative to nonforested areas.
The Relationship between Extreme Hourly Precipitation and Surface Temperature in Different Hydroclimatic Regions of the United States
Authors: Shaw Stephen B. , Royem A. Alisa , Riha Susan J.
Published: January 2011

In a changing climate, there is an interest in predicting how extreme rainfall events may change. Using historical records, several recent papers have evaluated whether high-intensity precipitation scales with temperature in accordance with the Clausius–Clapeyron (C–C) relationship. For varying locations in Europe, these papers have identified both super C–C relationships as well as a breakdown of the C–C relationship under dry conditions. In this paper, a similar analysis is carried out for the United States using data from 14 weather stations clustered in four different hydroclimatic regions: the coastal northeast, interior New York, the central plains, and the western plains. In all regions except interior New York state, 99th percentile 1-h precipitation generally followed the C–C relation. In interior New York, there was evidence that intensity scaled with a super C–C relationship. For the 99.9th percentile precipitation, interior New York displayed some moderate evidence of a super C–C relationship, the western plains showed little relation between precipitation and temperature, and the remainder of sites generally scaled with the C–C relationship. Also, if only July, August, and September precipitation is considered, all stations except those in interior New York have little relation between temperature and precipitation, suggesting that precipitation intensity during summer months may not be well constrained by the C–C relationship. Overall, the C–C relationship (or a variation thereof) does not appear to constrain extreme precipitation in all regions and in all seasons, and its ability to aid in constraining future predictions of extreme precipitation may only be relevant to certain locales and time periods.
“Eddy Resolving” Observation of the North Pacific Subtropical Mode Water
Authors: Oka Eitarou , Suga Toshio , Sukigara Chiho , Toyama Katsuya , Shimada Keishi , Yoshida Jiro
Published: January 2011

Hydrographic data obtained by high-resolution shipboard observations and Argo profiling floats have been analyzed to study the mesoscale structure and circulation of the North Pacific Subtropical Mode Water (STMW). The float data show that in the late winter of 2008, STMW having a temperature of approximately 18.8°, 17.7°, and 16.6°C formed west of 140°E, at 140°–150°E, and east of 150°E, respectively, in the recirculation gyre south of the Kuroshio Extension. After spring, the newly formed STMW gradually shift southward, decreasing in thickness. Simultaneously, the STMWs of 16.6° and 17.7°C are gradually stirred and then mixed in terms of properties. In late fall, they seem to be integrated to form a single group of STMWs having a temperature centered at 17.2°C. Such STMW circulation in 2008 is much more turbulent than that in 2006, which was investigated in a previous study. The difference between the two years is attributed to the more variable state of the Kuroshio Extension in 2008, associated with stronger eddy activities in the STMW formation region, which enhance the eddy transport of STMW.

High-resolution shipboard observations were carried out southeast of Japan at 141°–147°E in the early fall of 2008. To the south of the Kuroshio Extension, STMW exists as a sequence of patches with a horizontal scale of 100–200 km, whose thick portions correspond well to the mesoscale deepening of the permanent pycnocline. The western (eastern) hydrographic sections are occupied mostly by the 17.7°C (16.6°C) STMW, within which the 16.6°C (17.7°C) STMW exists locally, mostly at locations where both the permanent pycnocline depth and the STMW thickness are maximum. This structure implies that the STMW patches are transported away from their respective formation sites, corresponding to a shift in the mesoscale anticyclonic circulations south of the Kuroshio Extension. Furthermore, 20%–30% of the observed STMW pycnostads have two or three potential vorticity minima, mostly near temperatures of 16.6° and 17.7°C. The authors presume that such a structure formed as a result of the interleaving of the 16.6° and 17.7°C STMWs after they are stirred by mesoscale circulations, following which they are vertically mixed to form the 17.2°C STMW observed in late fall. These results indicate the importance of horizontal processes in destroying the vertically uniform structure of STMW after spring, particularly when the Kuroshio Extension is in a variable state.
Modification of Long Equatorial Rossby Wave Phase Speeds by Zonal Currents
Authors: Durland Theodore S. , Samelson Roger M. , Chelton Dudley B. , de Szoeke Roland A.
Published: January 2011

Previously unaddressed aspects of how equatorial currents affect long Rossby wave phase speeds are investigated using solutions of the shallow-water equations linearized about quasi-realistic currents. Modification of the background potential vorticity (PV) gradient by curvature in the narrow equatorial currents is shown to play a role comparable to the Doppler shift emphasized by previous authors. The important variables are the meridional projections of mean-current features onto relevant aspects of the wave field. As previously shown, Doppler shifting of long Rossby waves is determined by the projection of the mean currents onto the wave’s squared zonal-velocity and pressure fields. PV-gradient modification matters only to the extent that it projects onto the wave field’s squared meridional velocity.

Because the zeros of an equatorial wave’s meridional velocity are staggered relative to those of the zonal velocity and pressure, and because the meridional scales of the equatorial currents are similar to those of the low-mode Rossby waves, different parts of the current system dominate the advective and PV-gradient modification effects on a single mode. Since the equatorial symmetry of classical equatorial waves alternates between symmetric and antisymmetric with increasing meridional mode number, the currents produce opposite effects on adjacent modes. Meridional mode 1 is slowed primarily by a combination of eastward advection by the Equatorial Undercurrent (EUC) and the PV-gradient decrease at the peaks of the South Equatorial Current (SEC). The mode-2 phase speed, in contrast, is increased primarily by a combination of westward advection by the SEC and the PV-gradient increase at the core of the EUC.

Perturbation solutions are carried to second order in ε, the Rossby number of the mean current, and it is shown that this is necessary to capture the full effect of quasi-realistic current systems, which are asymmetric about the equator. Equatorially symmetric components of the current system affect the phase speed at O(ε), but antisymmetric components of the currents and distortions of the wave structures by the currents do not influence the phase speed until O(ε2).
Contrasting Response of the Eastern and Western North Atlantic Circulation to an Episodic Climate Event*
Authors: Chaudhuri Ayan H. , Gangopadhyay Avijit , Bisagni James J.
Published: January 2011

Regional observational studies in the North Atlantic have noted significant hydrographical shifts in 1997–98 because of the episodic drop in the North Atlantic oscillation (NAO) during 1996. Investigation using a basin-scale model finds that, although the western North Atlantic (WNA) witnessed unusually low-salinity water by 1997, the eastern North Atlantic (ENA) simultaneously evidenced intrusions of high-salinity water at intermediate depths. This study shows that a major source of high salinity in the ENA is from the northward penetration of Mediterranean Outflow Water (MOW) that occurred concurrently with a westward shift of the subpolar front. The authors confirm that the low-salinity intrusion in the WNA is from enhanced Labrador Current flow. Results from climatological high- and low-NAO simulations suggest that the NAO-induced circulation changes that occurred in 1997–98 are a characteristic North Atlantic basin response to different forcing conditions during characteristic high- and low-NAO periods.
Momentum Balance of the Wind-Driven and Meridional Overturning Circulation
Authors: Marshall David P. , Pillar Helen R.
Published: January 2011

When a force is applied to the ocean, fluid parcels are accelerated both locally, by the applied force, and nonlocally, by the pressure gradient forces established to maintain continuity and satisfy the kinematic boundary condition. The net acceleration can be represented through a “rotational force” in the rotational component of the momentum equation. This approach elucidates the correspondence between momentum and vorticity descriptions of the large-scale ocean circulation: if two terms balance pointwise in the rotational momentum equation, then the equivalent two terms balance pointwise in the vorticity equation. The utility of the approach is illustrated for three classical problems: barotropic Rossby waves, wind-driven circulation in a homogeneous basin, and the meridional overturning circulation in an interhemispheric basin. In the hydrostatic limit, it is shown that the rotational forces further decompose into depth-integrated forces that drive the wind-driven gyres and overturning forces that are confined to the basin boundaries and drive the overturning circulation. Potential applications of the approach to diagnosing the output of ocean circulation models, alternative and more accurate formulations of numerical ocean models, the dynamics of boundary layer separation, and eddy forcing of the large-scale ocean circulation are discussed.
Turbulence in a Sheared, Salt-Fingering-Favorable Environment: Anisotropy and Effective Diffusivities
Authors: Kimura Satoshi , Smyth William , Kunze Eric
Published: January 2011

Direct numerical simulations (DNS) of a shear layer with salt-fingering-favorable stratification have been performed for different Richardson numbers Ri and density ratios Rρ. In the absence of shear (Ri = ∞), the primary instability is square planform salt fingering, alternating cells of rising and sinking fluid. In the presence of shear, salt fingering takes the form of salt sheets, planar regions of rising and sinking fluid, aligned parallel to the sheared flow. After the onset of secondary instability, the flow becomes turbulent. The continued influence of the primary instability distorts the late-stage structure and hence biases isotropic estimates of the turbulent kinetic energy dissipation rate ε. In contrast, thermal and saline gradients evolve to become more isotropic than velocity gradients at their dissipation scales. Thus, the standard observational methodology of estimating the turbulent kinetic energy dissipation rate ε from vertical profiles of microscale gradients and assuming isotropy can underestimate its true value by a factor of 2–3, whereas estimates of thermal and saline dissipation rates using this approach are relatively accurate. Likewise, estimates of Γ from vertical profiles overestimate the true Γ by roughly a factor of 2. Salt sheets are ineffective at transporting momentum. Thermal and saline effective diffusivities decrease with decreasing Ri, despite the added energy source provided by background shear. After the transition to turbulence, the thermal to saline flux ratio and the effective Schmidt number remain close to the values predicted by linear theory.
Barotropic Rossby Waves Radiating from Tropical Instability Waves in the Pacific Ocean
Authors: Farrar J. Thomas
Published: January 2011

Tropical instability waves are triggered by instabilities of the equatorial current systems, and their sea level signal, with peak amplitude near 5°N, is one of the most prominent features of the dynamic topography of the tropics. Cross-spectral analysis of satellite altimetry observations shows that there is sea level variability in the Pacific Ocean as far north as Hawaii (i.e., 20°N) that is coherent with the sea level variability near 5°N associated with tropical instability waves. Within the uncertainty of the analysis, this off-equatorial variability obeys the dispersion relation for nondivergent, barotropic Rossby waves over a fairly broad range of periods (26–38 days) and zonal wavelengths (9°–23° of longitude) that are associated with tropical instability waves. The dispersion relation and observed wave properties further suggest that the waves are carrying energy away from the instabilities toward the North Pacific subtropical gyre, which, together with the observed coherence of the sea level signal of the barotropic waves with that of the tropical instability waves, suggests that the barotropic Rossby waves are being radiated from the tropical instability waves. The poleward transport of kinetic energy and westward momentum by these barotropic Rossby waves may influence the circulation in the subtropics.
Decadal Shifts of the Kuroshio Extension Jet: Application of Thin-Jet Theory*
Authors: Sasaki Yoshi N. , Schneider Niklas
Published: January 2011

Meridional shifts of the Kuroshio Extension (KE) jet on decadal time scales are examined using a 1960–2004 hindcast simulation of an eddy-resolving ocean general circulation model for the Earth Simulator (OFES). The leading mode of the simulated KE represents the meridional shifts of the jet on decadal time scales with the largest southward shift in the early 1980s associated with the climate regime shift in 1976/77, a result confirmed with subsurface temperature observations. The meridional shifts originate east of the date line and propagate westward along the mean jet axis, a trajectory inconsistent with the traditionally used linear long Rossby waves linearized in Cartesian coordinates, although the phase speed is comparable to that in the traditional framework. The zonal scale of these westward propagation signals is about 4000 km and much larger than their meridional scale. To understand the mechanism for the westward propagation of the KE jet shifts, the authors consider the limit of a thin jet. This dynamic framework describes the temporal evolution of the location of a sharp potential vorticity front under the assumption that variations along the jet are small compared to variations normal to the jet in natural coordinates and is well suited to the strong jet and potential vorticity gradients of the KE. For scaling appropriate to the decadal adjustments in the KE, the thin-jet model successfully reproduces the westward propagations and decadal shifts of the jet latitude simulated in OFES. These results give a physical basis for the prediction of decadal variability in the KE.
Dimensionally Consistent Similarity Relation of Ocean Surface Friction Coefficient in Mixed Seas*
Authors: Hwang Paul A. , García-Nava Héctor , Ocampo-Torres Francisco J.
Published: January 2011

Applying wavelength scaling, dimensionally consistent expressions of the ocean surface friction coefficient can be developed for both wind sea and mixed sea in the ocean. For a wind sea with a monopeak wave spectrum, the natural choice of the scaling wavelength is that of the spectral peak component. For a mixed sea with a multipeak spectrum, the peak component in the wind sea portion of the wave spectrum is not a good reference wavelength. A much better scaling wavelength is the weighted average of swell and wind sea following the consideration of equivalent momentum in the wave field. The resulting friction coefficient Cλ/2 is referenced to the wind speed at one-half of the scaling wavelength Uλ/2 instead of C10 referenced to the neutral wind speed at 10-m elevation U10. Although referencing the wind speed at a fixed elevation such as U10 is of practical necessity, Uλ/2 is physically significant as the free-stream velocity in wave-modulated boundary layer flows. A simple procedure to apply the similarity relation of Cλ/2 to obtain C10 is described.
The Influence of Island Topography on Typhoon Track Deflection
Authors: Huang Yi-Hsuan , Wu Chun-Chieh , Wang Yuqing
Published: January 2011

High-resolution simulations for Typhoon Krosa (2007) and a set of idealized experiments are conducted using a full-physics model to investigate the eminent deflection of typhoon track prior to its landfall over mountainous island topography. The terrain height of Taiwan plays the most important role in Typhoon Krosa’s looping motion at its landfall, while the surface properties, details in the topographic shape of Taiwan, and the cloud microphysics are shown to be secondary to the track deflection. A simulation with 3-km resolution and realistic model settings reproduces the observed Krosa’s track, while that with 9-km resolution fails, suggesting that high resolution to better resolve the typhoon–terrain interactions is important for the prediction and simulation of typhoon track deflection prior to landfall. Results from idealized experiments with model configurations mimicking those of Supertyphoon Krosa show that vortices approaching the northern and central topography are significantly deflected to the south before making sharp turns to the north, forming a kinked track pattern prior to and during landfall. This storm movement is consistent with the observed looping cases in Taiwan.

Both real-case and idealized simulations show strong channel winds enhanced between the storm and the terrain when deflection occurs. Backward trajectory analyses support the concept of the channeling effect, which has been previously found to be crucial to the looping motion of Typhoon Haitang (2005) as well. However, the inner-core asymmetric ventilation flow does not match the movement of a deflected typhoon perfectly, partly because the steering flow is not well defined and could not completely capture the terrain-induced deflection in the simulation and in nature.
Mechanical properties and morphology of nano-reinforced rigid PU foam
Authors: Dolomanova Viktoriya , Rauhe Jens Chr. M. , Jensen Lars Rosgaard , Pyrz Ryszard , Timmons Ana Barros
Published: January 2011

This study is dedicated to the investigation of the change in mechanical properties of rigid polyurethane foam reinforced with carbon nanoparticles. Pure and nano-reinforced polyurethane foams were produced by an in situ polymerization technique. Carbon nanotubes (single-walled carbon nanotubes and multi-walled carbon nanotubes) and carbon nanofibers were used as reinforcing particles. Diphenylmethane 4,4'-diisocyanate treatment of carbon nanoparticles was performed in order to improve the interaction of nanoparticles and polymer matrix. The alterations of morphology and mechanical properties of the nano-reinforced polyurethane foam were studied by varying the amount of both pristine and modified carbon nanoparticles. Compression tests revealed an improvement of both compressive Young’s modulus and compressive strength, and scanning electron microscope observations showed a decrease of the average cell size of the foam.
A Program to Improve the Quality of Emergency Endotracheal Intubation
Authors: Mayo Paul H. , Hegde Abhijith , Eisen Lewis A. , Kory Pierre , Doelken Peter
Published: January 2011

Objective: To assess the results of a quality improvement (QI) project designed to improve safety of emergency endotracheal intubation (EEI). Design: Single center prospective observational. Setting: 16-bed intensive care unit. Participants: Nine pulmonary/critical care fellows. Interventions: For 3 years, EEI performed by the medical intensive care unit team were analyzed to identify interventions that would improve quality of the procedure. By segmental process analysis, the procedure of EEI was subjected to iterative change. Major components of process improvement were development of a combined team approach, a mandatory checklist, use of crew resource management (CRM) tactics, and postevent debriefing. Quality analysis and improvement included training of fellows using scenario-based training (SBT) with computerized patient simulator (CPS) to improve mechanical skills of intubation and team leadership. Fellows received 15 sessions of SBT with CPS using a combined checklist and team approach before assuming team leadership position during real-life EEI. Measurements: For a 10-month period, fellows carried digital voice recorders to EEI; which, when combined with recording of continuous oximetry and BP monitoring were used to assess the quality of EEI. Main Results: 128 EEI were performed of which 101 had full data recorded. Complications were 14% severe hypoxemia (<80% saturation), 6% severe hypotension (SBP<70 mm Hg), 1% death, 20% difficult EEI (≥3 attempts), 11% esophageal intubations, 2% aspiration, and 1% dental injury; 62% EEI were successfully achieved on first attempt, 11% required >3 attempts. Conclusions: EEI may be performed by pulmonary/critical medicine (PCCM) fellows with safety comparable to that described in other studies on EEI. Important parts of the program included the use of formal iterative QI approach, the use of intensive SBT with CPS, basic CRM, a comprehensive checklist, and a combined team approach. A key benefit of the program was to make the process of EEI fully transparent for ongoing quality and safety improvement.
Analytic Review: Interleukin-6 in Surgery, Trauma, and Critical Care: Part I: Basic Science
Authors: Jawa Randeep S. , Anillo Sergio , Huntoon Kristin , Baumann Heinz , Kulaylat Mahmoud
Published: January 2011

A variety of cytokines play a role in the response to an inflammatory stimulus. The interleukin-6 (IL-6)-type cytokines are released in response to tissue injury or an inflammatory stimulus. They act locally and systemically to generate a variety of physiologic responses, principal among them is the acute phase response. The IL-6 type cytokines demonstrate pleiotropy and redundancy of actions. This is made possible by the distinctive characteristics of the IL-6 receptor complex, which contains an ubiquitous subunit that is shared by most IL-6-type cytokines, as well as a cytokine-specific subunit.
Freedom of expression, deliberation, autonomy and respect
Authors: Rostbøll Christian F.
Published: January 2011

This paper elaborates on the deliberative democracy argument for freedom of expression in terms of its relationship to different dimensions of autonomy. It engages the objection that Enlightenment theories pose a threat to cultures that reject autonomy and argues that autonomy-based democracy is not only compatible with but necessary for respect for cultural diversity. On the basis of an intersubjective epistemology, it argues that people cannot know how to live on mutually respectful terms without engaging in public deliberation and developing some degree of personal autonomy. While freedom of expression is indispensable for deliberation and autonomy, this does not mean that people have no obligations regarding how they speak to each other. The moral insights provided by deliberation depend on the participants in the process treating one another with respect. The argument is related to the Danish cartoon controversy.
Human dignity in historical perspective: The contemporary and traditional paradigms
Authors: Sensen Oliver
Published: January 2011

Over the last 60 years the idea of human dignity has become increasingly prominent in the political discourse on human rights. In United Nations documents, for instance, human dignity is currently presented as the justification for human rights. In this paper I shall argue that the contemporary way in which human dignity is thought to ground human rights is very different from the way human dignity has been understood traditionally. My aim is to contrast the contemporary paradigm of dignity to a different one that has been prominent historically from Cicero onwards. My conclusion is that if one wants to use the contemporary conception of dignity, one cannot refer to the history of philosophy for support of this conception, and if one wants to use this history in support, one would have to employ a different conception of dignity that uses a different pattern of thought.
Effect of type 2 diabetes on the dynamic response characteristics of leg vascular conductance during exercise
Authors: MacAnaney Oscar , Reilly Heather , O'Shea Donal , Egaña Mikel , Green Simon
Published: January 2011

In this study we tested the hypothesis that type 2 diabetes impairs the dynamic response of leg vascular conductance (LVC) during exercise. LVC (leg blood flow/mean arterial pressure) responses were studied during intermittent contractions of the calf muscle in subjects with type 2 diabetes ( n = 9), heavy controls ( n = 10) and lean controls ( n = 8) using a biexponential function and an estimate of the mean response time (MRT). The time constant of the second phase of LVC was significantly greater in type 2 diabetes (66.4 ± 29.2 s) than the heavy (22.2 ± 13.4 s) and lean (21.8 ± 9.3 s) controls, resulting in a significantly greater MRT in the diabetic group (median [IQR] = 30.7 [24.6—46.5] s versus 16.3 [4.3—23.2] s and 18.4 [13.7—19.3] s). These data support the hypothesis and suggest that a slowed hyperaemic response in the exercising limb might contribute to exercise intolerance in diabetic subjects.
Metformin decreases thyrotropin in overweight women with polycystic ovarian syndrome and hypothyroidism
Authors: Morteza Taghavi S. , Rokni Hale , Fatemi Sedigheh
Published: January 2011

Objective: To assess the effect of metformin administration on thyroid function in overweight women with polycystic ovarian syndrome (PCOS).

Methods: Twenty-seven overweight women with PCOS and hypothyroidism were selected. Fifteen patients (group I) were treated with metformin 1500 mg/day for 6 months and 12 patients (group II) with placebo. Serum thyrotropin (TSH), free T3 and free T4 were measured at baseline and 6 months after the beginning of the study.

Results: A significant decrease ( p<0.001) in TSH levels was observed in group I but not in group II subjects after 6 months of metformin treatment. No significant change in free T3 and free T4 was observed throughout the study in any group.

Conclusion: In obese PCOS patients with primary hypothyroidism, metformin results in a significant fall and sometimes normalisation of TSH, without causing any reciprocal changes in other thyroid function parameters.
Validation of the Chinese version of the Walking Impairment Questionnaire in patients with both peripheral arterial disease and type 2 diabetes mellitus
Authors: Jie Wang  , Yan Cui  , Bian Rong-Wen , Mo Yong-Zhen , HaiDi Wu  , Ling Chen
Published: January 2011

The aim of present study is to translate and validate a Chinese version of the WIQ in patients with PAD and T2DM. A cross-sectional survey was conducted. After translation, a convenience sample of 59 patients with PAD and T2DM completed the Chinese WIQ, the Chinese SF-36 and the 6MWT. The ICC and Cronbach’s alpha were calculated to determine the reliability and internal consistency, respectively.Validity was evaluated by correlation coefficients between WIQ, SF-36 and 6MWD. The internal consistency determined by Cronbach’s alpha was 0.93. Test—retest reliability expressed by ICC was 0.93. Significant correlations were observed between WIQ, SF-36 and 6MWD (ρ s=0.27 ∼0.88, p < 0.01).The Chinese version of the WIQ has satisfactory reliability and validity and can be used to assess walking ability in type 2 diabetic PAD patients.
Insulin resistance and cardiovascular disease risk factors in subjects with prehypertension
Authors: Knobler Hilla , Abbasi Fahim , Lamendola Cindy , Reaven Gerald M
Published: January 2011

Prehypertension is considered to be associated with increased cardiovascular disease (CVD), and some data suggest that insulin resistance is common in this group. The goal of this study was to quantify insulin action by determining the steady-state plasma glucose (SSPG) concentration during the insulin suppression test in apparently healthy individuals with prehypertension ( n=126) and to elucidate the relationship between insulin action and CVD risk.We found a marked heterogeneity in insulin sensitivity in the prehypertension group, and when we divided the population into insulin-sensitive, insulin-resistant and intermediate groups, there were significant ( p<0.01) increases in plasma glucose and triglyceride concentrations and decreases in high-density lipoprotein cholesterol concentrations with progressive degrees of insulin resistance. These data show that at least one-third of patients with prehypertension are insulin resistant, display the accompanying metabolic abnormalities, and merit enhanced surveillance and intensive efforts at therapeutic intervention to prevent CVD.
Isothiocyanatoluminol as a Chemiluminescence Labeling Reagent for Amino Acids and Proteins
Authors: Smanmoo Srung , Nasomphan Weerachai , Tangboriboonrat Pramuan
Published: January 2011

Isothiocyanatoluminol (ITL) was successfully synthesized from the reaction between luminol and thiophosgene in the presence of triethylamine. The optimized conditions were extended for the preparation of isothiocyanatoisoluminol (ITIL) and phenyl isothiocyanate (PI). The chemiluminescence (CL) of ITL was comparable to luminol. ITL was used as a CL labeling reagent for amino acid and bovine serum albumin (BSA) in which the –NH2 terminus of amino acid residue present in BSA acts as the labeling site.
Spiral Pattern Formation on Bulk Metallic Glass by Electropolishing
Authors: Kido Hideki , Fujita Kazutaka , Osaki Koichi , Sakurai Tatsunari , Inoue Akihisa
Published: January 2011

Spiral patterns that have concave and convex surfaces were discovered on a bulk metallic glass (BMG), Zr55Cu30Al10Ni5 atom % alloy after electropolishing under certain conditions. The observed spiral pattern had a wavelength of 2.4 µm and peaks that were 0.19 µm high. Electropolishing produces smooth metal and alloy surfaces. These patterns depend on the spatiotemporal properties during electropolishing.