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Sample records for related transport cross

  1. Elastic and transport properties in polycrystals of crackedgrains: Cross-property relations and microstructure

    SciTech Connect

    Berryman, J.G.

    2007-10-02

    Some arguments of Bristow (1960) concerning the effects of cracks on elastic and transport (i.e., electrical or thermal conduction) properties of cold-worked metals are reexamined. The discussion is posed in terms of a modern understanding of bounds and estimates for physical properties of polycrystals--in contrast to Bristow's approach using simple mixture theory. One type of specialized result emphasized here is the cross-property estimates and bounds that can be obtained using the methods presented. Our results ultimately agree with those of Bristow, i.e., confirming that microcracking is not likely to be the main cause of the observed elastic behavior of cold-worked metals. However, it also becomes clear that the mixture theory approach to the analysis is too simple and that crack-crack interactions are necessary for proper quantitative study of Bristow's problem.

  2. Cross-property relations for momentum and diffusional transport in porous media

    NASA Astrophysics Data System (ADS)

    Torquato, S.; Kim, In Chan

    1992-10-01

    Cross-property relations linking the fluid permeability k associated with viscous flow through a porous medium to effective diffusion properties of the medium have recently been derived. Torquato [Phys. Rev. Lett. 64, 2644 (1990)] found that k≤Dφ1τ, where τ is the ``mean survival time'' associated with steady-state diffusion of ``reactants'' in the fluid region of diffusion coefficient D and porosity φ1 of a porous medium containing absorbing walls (i.e., trap boundaries). Subsequently, Avellaneda and Torquato [Phys. Fluids A 3, 2529 (1991)] related k to the electrical formation factor F (inverse of the dimensionless effective electrical conductivity) and the principal (largest) diffusion relaxation time T1 associated with the time-dependent trapping problem, namely, k≤DT1/F. In this study, we compute the aforementioned bounds, using an efficient first-passage-time algorithm, for grain-consolidation models of porous media and compare them to exact results for these models. We also conjecture a new relation connecting k to τ and F for a wide class of porous media, namely, k≤Dτ/F, and show that it gives the sharpest permeability estimate among the existing bounds. The importance of this relation lies not only in its usefulness as an estimator of the permeability but that it involves the diffusional parameters τ and F which can be measured in situ.

  3. Elastic, charge transfer, and related transport cross sections for proton impact of atomic hydrogen for astrophysical and laboratory plasma modeling

    NASA Astrophysics Data System (ADS)

    Schultz, D. R.; Ovchinnikov, S. Yu; Stancil, P. C.; Zaman, T.

    2016-04-01

    Updating and extending previous work (Krstić and Schultz 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3458 and other references) comprehensive calculations were performed for elastic scattering and charge transfer in proton—atomic hydrogen collisions. The results, obtained for 1301 collision energies in the center-of-mass energy range of 10-4-104 eV, are provided for integral and differential cross sections relevant to transport modeling in astrophysical and other plasma environments, and are made available through a website. Use of the data is demonstrated through a Monte Carlo transport simulation of solar wind proton propagation through atomic hydrogen gas representing a simple model of the solar wind interaction with heliospheric neutrals.

  4. The Relative Importance of Cross- and Along-shore Sediment Transport in Planform and Profile Adjustments of a Gravel Barrier Beach

    NASA Astrophysics Data System (ADS)

    Buscombe, D.; Ruiz de Alegria, A.; Masselink, G.

    2008-12-01

    Slapton is a macrotidal gravel barrier beach in Devon, UK. Its stability is threatened by accelerated sea-level rise and long-term (decadal-centurial scale) redistributions of sediment alongshore between adjacent beaches within Start Bay. Fortnightly surveys have been conducted regularly at spring low tide since October 2006. An ARGUS camera system has continuously monitored the beach since the autumn of 2005. Historical observations and measured profiles taken by the Field Studies Council Slapton Ley, have been made since 1972. In addition, several field campaigns have been carried out, in autumn 2005 and springs of 2007 and 2008, measuring profile response over tidal- and sub-tidal cycle timescales. The relative importance of sediment transport gradients operating in the cross- and along-shore directions, and resulting net sedimentation patterns and changes in the beach profile and planform, has scale- dependency. Despite being 'swash-aligned', planform adjustments induced by alongshore gradients in sediment transport are dominant. Modelled net alongshore sediment transport rates are at least an order of magnitude greater than those derived from measurements, and thus these models must be treated as transport potentials, and require improvement. At time scales at or less than a tidal cycle, beachface change is dominated by cross-shore sedimentation, and although lack of sediment continuity over these scales suggests some net alongshore transport, antecedent cross-shore sedimentation dictates where and for how long. During storms, whilst the immediate manifestation of change is cross-shore, the antecedent along- shore redistribution of sediment has a crucial role to play in determining the general integrity of the barrier, as well as the location and magnitude of overwash and significant shoreline recession. The complicated interplay between cross- and along-shore sedimentation processes, at overlapping scales, highlights the importance of continuous monitoring

  5. Cross-shore sediment transport on natural beaches and its relation to sandbar migration patterns: 2. Application of the field transport parameterization

    NASA Astrophysics Data System (ADS)

    MariñO-Tapia, I. J.; O'Hare, T. J.; Russell, P. E.; Davidson, M. A.; Huntley, D. A.

    2007-03-01

    A cross-shore sediment transport parameterization (shape function) based on data from intensive field experiments carried out on five European beaches is incorporated into a simple time dependent model to explore its capability for reproducing sandbar generation and evolution in the medium term (O(months)). Model results are compared with bar-crest migration patterns observed at Duck, North Carolina. The model comprises a simple wave transformation routine that accounts for linear shoaling and assumes a saturation law for wave decay inside the surf zone. Second-order statistics derived from the cross-shore distribution of wave heights are used to scale the sediment transport parameterizations which estimate the cross-shore structure of the third and fourth velocity moments. Cross-shore gradients in sediment fluxes, calculated with an energetics approach, produce bed elevation changes. The updated morphology affects the wave propagation in the next time step forming a fully coupled model for predicting sandbar evolution. Bar generation close to shore and the details of the sandbar evolution are successfully reproduced (R2 = 0.86) over the 77-day period of the observations using default values for drag coefficients and efficiency factors. In accordance with the observations, the model shows rapid offshore sandbar migration in response to individual storms, and weak onshore bar movement for lower energy conditions. Owing to its simple nature, the model is not capable of reproducing the whole profile morphology especially in the trough (no trough generation), and it is only valid for replicating bar crest position. The results suggest that a convergence of sediment near the breakpoint (breakpoint hypothesis) combined with morphological feedback, can successfully explain the evolution of bar crest over periods of months from the details of forcing (incident waves and water levels).

  6. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Worldwide Marine Transportation Network: Efficiency and Container Throughput

    NASA Astrophysics Data System (ADS)

    Deng, Wei-Bing; Guo, Long; Li, Wei; Cai, Xu

    2009-11-01

    Through empirical analysis of the global structure of the Worldwide Marine Transportation Network (WMTN), we find that the WMTN, a small-world network, exhibits an exponential-like degree distribution. We hereby investigate the efficiency of the WMTN by employing a simple definition. Compared with many other transportation networks, the WMTN possesses relatively low efficiency. Furthermore, by exploring the relationship between the topological structure and the container throughput, we find that strong correlations exist among the container throughout the degree and the clustering coefficient. Also, considering the navigational process that a ship travels in a real shipping line, we obtain that the weight of a seaport is proportional to the total probability contributed by all the passing shipping lines.

  7. Elastic and Related Transport Cross Sections, Charge Transfer: Data from the Controlled Fusion Atomic Data Center (CFADC)

    DOE Data Explorer

    Krstic, P. S; Schultz, D. R.

    Data files available in this section of the Controlled Fusion Atomic Data Center (CFADC) are found under the following headings: • Isotopomers of hydrogen ions, atoms and molecules and helium • Vibrationally excited states of hydrogen molecule with proton, and hydrogen molecular ion with hydrogen • Isotopomers of hydrogen ions with carbon • Isotopomers of hydrogen ions with argon • Hydrogen ions with neon • Hydrogen ions with krypton • Hydrogen ions with xenon • Elastic and other cross sections from ApJ xxx, yyyy (2008) Each heading is a link to more information, the data, and customized interfaces. (Specialized Interface)

  8. Interaction between serotonin transporter gene-linked polymorphic region (5-HTTLPR) and job-related stress in insomnia: a cross-sectional study in Sichuan, China.

    PubMed

    Huang, Chan; Li, Ju; Lu, Lingeng; Ren, Xiaohui; Li, Yongru; Huang, Qian; Lan, Yajia; Wang, Yongwei

    2014-10-01

    Insomnia, a widely occurring sleep disorder in modern society, has a large impact on life quality and work safety. A cross-sectional study was conducted to explore the possible link between serotonin transporter-linked polymorphic region (5-HTTLPR), job-related stress, and insomnia in West China. Of the total 462 workers recruited, 177 had insomnia according to the Athens Insomnia Scale (AIS-5). The 5-HTTLPR genotypes were determined by polymerase chain reaction. Job-related stress was assessed for each participant by the General Job Stress Questionnaire. Unconditional logistic regression models showed that the 5-HTTLPR genotype was significantly associated with insomnia, and >80% increased risk per S allele was observed. High job-related stress had a higher risk for insomnia than low job-related stress (odds ratio [OR], 6.14; 95% confidence interval [CI], 3.94-9.59). Crossover analysis found significant job-related stress × 5-HTTLPR interaction. Compared to individuals with both low job-related stress and SL/LL genotype, those with both higher job-related stress and SS genotype had a higher risk of insomnia (OR, 5.16; 95% CI, 3.13-8.54), whereas those with both low job-related stress and SS genotype showed a lower risk of insomnia (OR, 0.26; 95% CI, 0.08-0.74). The interaction remained statistically significant after adjusting for potential confounding factors. The findings indicated that 5-HTTLPR could modify the effect of job-related stress on employees' insomnia, suggesting that a work environment-based personalized intervention may be applied to prevent employees' insomnia by alleviating job-related stress in the workplace. Copyright © 2014. Published by Elsevier B.V.

  9. Young adolescents' independent mobility, related factors and association with transport to school. A cross-sectional study.

    PubMed

    Johansson, Klara; Hasselberg, Marie; Laflamme, Lucie

    2010-10-22

    Children's independent mobility differs between groups of adolescents, but knowledge is lacking on how mobility-limiting factors interact. This study explores the association between factors that can affect young adolescents' mobility, searching for typical patterns within a geographical area where mobility is both relatively high and promoted (in this case Stockholm County, Sweden). An additional question is how clusters of limiting factors and demographic attributes relate to active commuting to school. A sample of 7th grade students (ca 13-14 years old) in Stockholm County, Sweden, answered a survey (n = 1008). A cluster analysis was performed on variables descriptive of the respondents and of potential limitations to their independent mobility, such as fears, coping, traffic situation in the neighbourhood and parent/child opinions on mobility (18 variables and 50 categories). Active commuting to/from school was compared using proportion (with 95% confidence intervals) by cluster. Five consistent and distinct clusters were identified. Among the most discriminating factors were fears experienced in the neighbourhood, strategies to cope with fear, type of housing and traffic environment. Girls were over-represented in the two clusters most typical of respondents experiencing fears (either several of these or darkness in particular) and boys in two others where housing (house vs. apartment) and neighbourhood conditions played a more determinant role. The proportion of active commuting among respondents was quite similar over clusters but was nonetheless higher in the cluster (over girls) reporting more fears and other factors limiting mobility. Whereas fears--and coping--are more typical of adolescent girls in the formation of the clusters, household and neighbourhood characteristics are more typical of boys. Broadly speaking, there seem to be two groups of girls with fears but these differ based on types of fear, ways of coping with fear and their living

  10. Transportation. The Neglected Related Service.

    ERIC Educational Resources Information Center

    Carter, Mary; And Others

    This monograph presents a five-module staff training program used to improve the related service of transportation of children with disabilities in Union County, North Carolina. Each module takes from 4 to more than 8 hours of training and bus drivers and transportation safety assistants with current certificates in all five modules receive a…

  11. The importance of transport parameter cross correlations in natural systems radioactive transport models

    SciTech Connect

    Reimus, Paul W

    2011-01-03

    Transport parameter cross correlations are rarely considered in models used to predict radionuclide transport in natural systems. In this paper, it is shown that parameter cross correlations could have a significant impact on radionuclide transport predictions in saturated media. In fractured rock, the positive correlation between fracture apertures and groundwater residence times is shown to result in significantly less retardation due to matrix diffusion than is predicted without the correlation. The suppression of matrix diffusion is further amplified by a tendency toward larger apertures, smaller matrix diffusion coefficients, and less sorption capacity in rocks of lower matrix porosity. In a hypothetical example, strong cross correlations between these parameters result in a decrease in predicted radionuclide travel times of an order of magnitude or more relative to travel times calculated with uncorrelated parameters. In porous media, expected correlations between permeability, porosity, and sorption capacity also result in shorter predicted travel times than when the parameters are assumed to be uncorrelated. Individual parameter standard deviations can also have a significant influence on predicted radionuclide travel times, particularly when cross correlations are considered.

  12. Sensitivity of Cross-Tropopause Convective Transport to Tropopause Definition

    NASA Astrophysics Data System (ADS)

    Maddox, E.; Mullendore, G. L.

    2016-12-01

    An idealized three-dimensional cloud-resolving model is used to simulate cross-tropopause boundary layer mass transport in a midlatitude supercell. A ten-hour simulation is conducted to encompass the growth and decay cycle, with focus on irreversible transport above the tropopause. However, several tropopause definitions are present in the literature, and the impact of tropopause definition on irreversible cross-tropopause transport has not been quantified. Six previously published tropopause definitions are evaluated to determine the sensitivity of tropopause definition on midlatitude irreversible cross-tropopause transport. These definitions include specific values of altitude, temperature lapse rate (i.e., WMO definition), potential vorticity, stratospheric tracer concentration, static stability, and curvature of static stability. This investigation highlights the challenge of defining a tropopause during active deep convection and shows that some definitions (e.g., potential vorticity) may not be appropriate for cross-tropopause transport studies that resolve deep convection.

  13. Cross-shelf transport and dispersion due to baroclinic instabilities

    NASA Astrophysics Data System (ADS)

    Thyng, Kristen; Hetland, Robert

    2014-05-01

    The dominant forcing mechanisms for the circulation in the northwestern Gulf of Mexico are largely determined by location relative to the shelf break. On the inner shelf, the flow is mostly controlled by the wind and on the outer shelf is affected by the mesoscale loop-current eddies. However, in the summer, baroclinic instabilities can develop along the boundary of the mid-shelf river plume front, leading to large eddies (~50 km length scale) that can reach across the entire shelf and strongly affect the local flow field. These instabilities advect fresher water toward the shelf edge and pull denser water back toward the coast. The details of how the flow crosses between these two regimes is of interest because it controls the flux of river-borne biogeochemical properties to the deep ocean, as well as for the potential onshore transport of oil from offshore spills. We approach this problem using a high resolution numerical model of the Texas-Louisiana shelf run using the Regional Ocean Modeling System (ROMS) and a Lagrangian particle tracking model (TRACMASS). By initializing drifters at the sources of fresh water (the Atchafalaya and Mississippi rivers) in the numerical model, we are able to explicitly track its trajectory through the numerical domain in time. These trajectories can then be used to characterize the cross-shelf transport and lateral dispersion due to the instabilities caused by the presence of the fresher water. We expect the transport and dispersion to be enhanced when compared with these quantities at other times of the year when the instabilities are not present, as well as with other regions of the shelf break that are farther from the plume edge area. Additionally, an idealized numerical model of a shelf break with both horizontal and vertical density gradients has been run through relevant parameter spaces to examine the range of baroclinic instabilities. Drifters are run in these simulations for comparison of transport and dispersion with

  14. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Synthesis and high temperature thermoelectric transport properties of Si-based type-I clathrates

    NASA Astrophysics Data System (ADS)

    Deng, Shu-Kang; Tang, Xin-Feng; Tang, Run-Sheng

    2009-07-01

    N-type Si-based type-I clathrates with different Ga content were synthesized by combining the solid-state reaction method, melting method and spark plasma sintering (SPS) method. The effects of Ga composition on high temperature thermoelectric transport properties were investigated. The results show that at room temperature, the carrier concentration decreases, while the carrier mobility increases slightly with increasing Ga content. The Seebeck coefficient increases with increasing Ga content. Among all the samples, Ba7.93Ga17.13Si28.72 exhibits higher Seebeck coefficient than the others and reaches -135 μV.K-1 at 1000 K. The sample prepared by this method exhibits very high electrical conductivity, and reaches 1.95×105 S.m-1 for Ba8.01Ga16.61Si28.93 at room temperature. The thermal conductivity of all samples is almost temperature independent in the temperature range of 300-1000 K, indicating the behaviour of a typical metal. The maximum ZT value of 0.75 is obtained at 1000 K for the compound Ba7.93Ga17.13Si28.72.

  15. Cross-sectional Survey of Canadian Pediatric Critical Care Transport.

    PubMed

    Kawaguchi, Atsushi; Gunz, Anna; de Caen, Allan

    2016-08-20

    This study aimed to better understand the unique aspects of pediatric critical care transport programs across Canada by characterizing the current workforce of each transport program. A cross-sectional questionnaire was sent to the 13 medical directors of Canada's pediatric critical care transport teams, and to 2 nonhospital-affiliated transport services. If a children's hospital did not have a dedicated team for pediatric transport, the regional transport team providing this service was identified. Eight of the 13 pediatric intensive care units surveyed have unit-based pediatric transport teams. The median annual transport volume for the 8 hospital-based teams was 371 (range, 45-2300) with a total of 5686 patients being transported annually. Among patients transported by the 8 teams, 45% (2579 patients) were pediatric patients (older than 28 days and younger than 18 years) and 40% (1022 patients) of the pediatric patients were admitted to the pediatric intensive care units. Eighty-eight percent of the responding teams also transported neonates (older than 28 days), and 38% transported premature infants.A team composition of registered nurse-respiratory therapist-physician was used by 6/13 teams (75%); however, it accounted for only a small proportion of the transports for most of the teams (median, 2%; range, 2%-100%).The average transport time from dispatch (from team home site) to arrival at receiving facility was reported by 6 teams, and has a median of 195 minutes (range, 90-360 minutes). The median distance from home site to the farthest referral site in the catchment area was 700 km (range, 15-2500 km). This is the first Canadian nationwide study of pediatric critical care transport programs. It revealed a complexity and variability in transport team demographics, transport volume, team composition, and decision-making process.

  16. Cross-Sectional Transport Imaging in a Multijunction Solar Cell

    SciTech Connect

    Haegel, Nancy M.; Ke, Chi-Wen; Taha, Hesham; Guthrey, Harvey; Fetzer, C. M.; King, Richard

    2015-06-14

    Combining highly localized electron-beam excitation at a point with the spatial resolution capability of optical near-field imaging, we have imaged carrier transport in a cross-sectioned multijunction (GaInP/GaInAs/Ge) solar cell. We image energy transport associated with carrier diffusion throughout the full width of the middle (GaInAs) cell and luminescent coupling from point excitation in the top cell GaInP to the middle cell. Supporting cathodoluminescence and near-field photoluminescence measurements demonstrate excitation-dependent Fermi level splitting effects that influence cross-sectioned spectroscopy results as well as transport limitations on the spatial resolution of cross-sectional measurements.

  17. Electron cross-sections and transport in liquids and biomolecules

    NASA Astrophysics Data System (ADS)

    White, Ronald; Casey, M.; Cocks, D.; Konvalov, D.; Brunger, M. J.; Garcia, G.; Petrovic, Z.; McEachran, R.; Buckman, S. J.; de Urquijo, J.

    2016-09-01

    Modelling of electron induced processes in plasma medicine and radiation damage is reliant on accurate self-consistent sets of cross-sections for electrons in tissue. These cross-sections (and associated transport theory) must accurately account not only the electron-biomolecule interactions but also for the soft-condensed nature of tissue. In this presentation, we report on recent swarm experiments for electrons in gaseous water and tetrahydrofuran using the pulsed-Townsend experiment, and the associated development of self-consistent cross-section sets that arise from them. We also report on the necessary modifications to gas-phase cross-sections required to accurately treat electron transport in liquids. These modifications involve the treatment of coherent scattering and screening of the electron interaction potential as well as the development of a new transport theory to accommodate these cross-sections. The accuracy of the ab-initio cross-sections is highlighted through comparison of theory and experiment for electrons in liquid argon and xenon.

  18. The relative cost of biomass energy transport.

    PubMed

    Searcy, Erin; Flynn, Peter; Ghafoori, Emad; Kumar, Amit

    2007-04-01

    Logistics cost, the cost of moving feedstock or products, is a key component of the overall cost of recovering energy from biomass. In this study, we calculate for small- and large-project sizes, the relative cost of transportation by truck, rail, ship, and pipeline for three biomass feedstocks, by truck and pipeline for ethanol, and by transmission line for electrical power. Distance fixed costs (loading and unloading) and distance variable costs (transport, including power losses during transmission), are calculated for each biomass type and mode of transportation. Costs are normalized to a common basis of a giga Joules of biomass. The relative cost of moving products vs feedstock is an approximate measure of the incentive for location of biomass processing at the source of biomass, rather than at the point of ultimate consumption of produced energy. In general, the cost of transporting biomass is more than the cost of transporting its energy products. The gap in cost for transporting biomass vs power is significantly higher than the incremental cost of building and operating a power plant remote from a transmission grid. The cost of power transmission and ethanol transport by pipeline is highly dependent on scale of project. Transport of ethanol by truck has a lower cost than by pipeline up to capacities of 1800 t/d. The high cost of transshipment to a ship precludes shipping from being an economical mode of transport for distances less than 800 km (woodchips) and 1500 km (baled agricultural residues).

  19. Interpreting sediment transport data with channel cross section analysis

    NASA Astrophysics Data System (ADS)

    Park, J.; Hunt, J. R.

    2013-12-01

    Suspended sediment load estimation is important for the management of stream environments. However suspended load data are uncommon and scalable models are needed to take maximum advantage of the measurements available. One of the most commonly used models for correlating suspended sediment load is an empirical power law relationship (Qs=aQ^b, Qs: suspended load, Q: flow rate). However, the relationship of log-scaled suspended load to flow rate has multiple exponents for different flow regimes at a given site, so a single power law relationship is not a good fit. Thus we are exploring an alternative approach that employs channel cross section data historically collected by the US Geological Survey during stream gauge calibration. For our research, daily flow and sediment discharge were selected from about 180 possible USGS gauging sites in California. Among those, about 20 sites were relatively unaffected by human activities, and had more than three years of data including near monthly measurements of channel cross section data. From our analysis, a slope break was consistently observed in the relationship of log-scaled suspended load to flow rate as illustrated in Figure 1 for Redwood Creek at Orick, CA. Most of the selected natural sites clearly show this slope break. The slope break corresponds to a transition of flow from a flat, wide stream to flow constrained by steep banks as verified in Figure 2 for the same site. This suggests that physical factors in the streams such as shear stress are affected by this channel morphological change and result in the greater exponent of sediment load during higher flow regime. Figure1. Daily values of measured sediment transport and flow rate reported by USGS between 1970 and 2001. Figure2. Near monthly values of measured mean water depth and width reported by USGS between 1969 and 1987.

  20. Contrasting local retention and cross-shore transports of the East Australian Current and the Leeuwin Current and their relative influences on the life histories of small pelagic fishes

    NASA Astrophysics Data System (ADS)

    Condie, S. A.; Mansbridge, J. V.; Cahill, M. L.

    2011-03-01

    Transport between shelf and offshore environments supports a significant proportion of ocean primary productivity and is critical to the life cycle of many marine species. While fundamental differences in the underlying dynamics of eastern and western boundary currents have been recognized and studied for more than half a century, the implications for physical dispersal rates have received much less attention. In this study we explore how Australia's two major boundary current systems, the East Australian Current and the Leeuwin Current, differ in their local retention and cross-shore transports in the upper water column and how these differences favor contrasting life histories of small pelagic fishes. The results suggest that the East Australian Current forms a partial barrier to onshore transport, but is effective in entraining shelf waters and transporting them offshore, particularly in the region where the current separates from the coast. Blue mackerel ( Scomber australasicus) spawn on the outer-shelf in this separation region and may thereby maximize the dispersion of eggs and larvae in the mainly oligotrophic waters of the southern Coral Sea. In contrast, the Leeuwin Current system promotes onshore transport through the combined effects of mean onshore flow and eddy-induced mixing. In the Great Australian Bight, sardine ( Sardinops sagax) and anchovy ( Engraulis australis) may exploit the high coastal retention of the Leeuwin Current system by spawning on the inner-shelf during summer when the current is weakest and winds assist retention and enhance production through local upwelling.

  1. Precise Relative Earthquake Magnitudes from Cross Correlation

    DOE PAGES

    Cleveland, K. Michael; Ammon, Charles J.

    2015-04-21

    We present a method to estimate precise relative magnitudes using cross correlation of seismic waveforms. Our method incorporates the intercorrelation of all events in a group of earthquakes, as opposed to individual event pairings relative to a reference event. This method works well when a reliable reference event does not exist. We illustrate the method using vertical strike-slip earthquakes located in the northeast Pacific and Panama fracture zone regions. Our results are generally consistent with the Global Centroid Moment Tensor catalog, which we use to establish a baseline for the relative event sizes.

  2. Precise Relative Earthquake Magnitudes from Cross Correlation

    SciTech Connect

    Cleveland, K. Michael; Ammon, Charles J.

    2015-04-21

    We present a method to estimate precise relative magnitudes using cross correlation of seismic waveforms. Our method incorporates the intercorrelation of all events in a group of earthquakes, as opposed to individual event pairings relative to a reference event. This method works well when a reliable reference event does not exist. We illustrate the method using vertical strike-slip earthquakes located in the northeast Pacific and Panama fracture zone regions. Our results are generally consistent with the Global Centroid Moment Tensor catalog, which we use to establish a baseline for the relative event sizes.

  3. Investigation of anisotropic thermal transport in cross-linked polymers

    NASA Astrophysics Data System (ADS)

    Simavilla, David Nieto

    Thermal transport in lightly cross-linked polyisoprene and polybutadine subjected to uniaxial elongation is investigated experimentally. We employ two experimental techniques to assess the effect that deformation has on this class of materials. The first technique, which is based on Forced Rayleigh Scattering (FRS), allows us to measure the two independent components of the thermal diffusivity tensor as a function of deformation. These measurements along with independent measurements of the tensile stress and birefringence are used to evaluate the stress-thermal and stress-optic rules. The stress-thermal rule is found to be valid for the entire range of elongations applied. In contrast, the stress-optic rule fails for moderate to large stretch ratios. This suggests that the degree of anisotropy in thermal conductivity depends on both orientation and tension in polymer chain segments. The second technique, which is based on infrared thermography (IRT), allows us to measure anisotropy in thermal conductivity and strain induced changes in heat capacity. We validate this method measurements of anisotropic thermal conductivity by comparing them with those obtained using FRS. We find excellent agreement between the two techniques. Uncertainty in the infrared thermography method measurements is estimated to be about 2-5 %. The accuracy of the method and its potential application to non-transparent materials makes it a good alternative to extend current research on anisotropic thermal transport in polymeric materials. A second IRT application allows us to investigate the dependence of heat capacity on deformation. We find that heat capacity increases with stretch ratio in polyisoprene specimens under uniaxial extension. The deviation from the equilibrium value of heat capacity is consistent with an independent set of experiments comparing anisotropy in thermal diffusivity and conductivity employing FRS and IRT techniques. We identify finite extensibility and strain

  4. Electron Transport Simulations of 4-Terminal Crossed Graphene Nanoribbons Devices

    NASA Astrophysics Data System (ADS)

    Brandimarte, Pedro; Papior, Nick R.; Engelund, Mads; Garcia-Lekue, Aran; Frederiksen, Thomas; Sánchez-Portal, Daniel

    Recently, it has been reported theoretically a current switching mechanism by voltage control in a system made by two perpendicular 14-armchair graphene nanoribbons (GNRs). In order to investigate the possibilities of using crossed GNRs as ON/OFF devices, we have studied their electronic and transport properties as function structural parameters determining the crossing. Our calculations were performed with TranSIESTA code, which has been recently generalized to consider N >= 1 arbitrarily distributed electrodes at finite bias. We find that the transmission along each individual GNR and among them strongly depends on the stacking. For a 60° rotation angle, the lattice matching in the crossing region provokes a strong scattering effect that translates into an increased interlayer transmission. FP7 FET-ICT PAMS-project (European Commission, contract 610446), MINECO (Grant MAT2013-46593-C6-2-P) and Basque Dep. de Educación, UPV/EHU (Grant IT-756-13).

  5. Biophysical Modeling of Cross-Shore Plankton Transport

    NASA Astrophysics Data System (ADS)

    Fujimura, A.; Reniers, A.; Paris, C. B.; Shanks, A.; MacMahan, J.; Morgan, S.

    2016-02-01

    Coastal ecosystems are influenced by cross-shore flows. Processes that create coastal plankton distributions are not well understood, even though possible mechanisms of plankton transport in the surf zone have been investigated. Our data from a rip-channeled beach show that concentrations of zooplankton and phytoplankton are higher in the surf zone than offshore. To examine how plankton are transported toward the shore, we used a coupled biophysical model, comprised of Delft3D wave/flow simulations and an individual-based model for tracking plankton. Model results indicate that onshore delivery of zooplankton is enhanced by Stokes drift, wave-driven bottom boundary streaming, alongshore topographic variability, and turbulence-dependent sinking behavior of zooplankton. Phytoplankton sinking may also be accelerated by turbulence, but the mechanism differs from that which affects zooplankton. Turbulence has the potential to increase phytoplankton growth rates. Therefore, the phytoplankton transport model includes turbulence-induced sinking velocity and growth rate, although the latter appears to have little influence on phytoplankton distributions. Modeled phytoplankton concentrations in the surf zone are much lower than expected, although the zooplankton transport model qualitatively reproduced our observations. Thus, there must be other possible factors influencing phytoplankton transport, some of which will be discussed.

  6. Cross-scale energy transport in space plasmas

    NASA Astrophysics Data System (ADS)

    Moore, T. W.; Nykyri, K.; Dimmock, A. P.

    2016-12-01

    The solar wind is a supersonic magnetized plasma streaming far into the heliosphere. Although cooling as it flows, it is rapidly heated upon encountering planetary obstacles. At Earth, this interaction forms the magnetosphere and its sub-regions. The present paper focuses on particle heating across the boundary separating the shocked solar wind and magnetospheric plasma, which is driven by mechanisms operating on fluid, ion and electron scales. The cross-scale energy transport between these scales is a compelling and fundamental problem of plasma physics. Here, we present evidence of the energy transport between fluid and ion scales: free energy is provided in terms of a velocity shear generating fluid-scale Kelvin-Helmholtz instability. We show the unambiguous observation of an ion-scale magnetosonic wave packet, inside a Kelvin-Helmholtz vortex, with sufficient energy to account for observed ion heating. The present finding has universal consequences in understanding cross-scale energy transport, applicable to environments experiencing velocity shears during comparable plasma regimes.

  7. Electron transport in argon in crossed electric and magnetic fields

    PubMed

    Ness; Makabe

    2000-09-01

    An investigation of electron transport in argon in the presence of crossed electric and magnetic fields is carried out over a wide range of values of electric and magnetic field strengths. Values of mean energy, ionization rate, drift velocity, and diffusion tensor are reported here. Two unexpected phenomena arise; for certain values of electric and magnetic field we find regions where the swarm mean energy decreases with increasing electric fields for a fixed magnetic field and regions where swarm mean energy increases with increasing magnetic field for a fixed electric field.

  8. Cross-channel patterns of bed material transport in a poorly sorted sand-bed channel

    NASA Astrophysics Data System (ADS)

    Haschenburger, J. K.

    2016-11-01

    Understanding of sediment transport comes largely from studies conducted on well-sorted sand-bed and poorly sorted gravel-bed channels. The aim of this study is to evaluate cross-channel patterns of transport rate and grain size in a poorly sorted sand-bed channel. Transport observations were collected from the San Antonio River using a Helley-Smith sampler during flows from 0.02 to 1.1 times bankfull capacity. Resulting transport rates and grain size distributions were pooled to describe eight sections across a channel transect that includes the lower bank and compared to local boundary material. Maximum transport rates are concentrated in the central zone of the streambed regardless of flow level, but gravels and coarse sands are conveyed preferentially on one side of the bed. Grain size distributions change relatively little with flow and approximate the local bed material supply. The size distributions associated with smaller transport rates near the channel margin become finer and more closely approximate the size characteristics of bank material at higher flows. Results extend patterns of differential routing of grain sizes to channel banks and establish the relative fluxes between the bed and bank environments. The small gravel content in poorly sorted sand beds requires further attention because it can contribute to cross-channel variation in sediment fluxes, limit the development of sandy bedforms, and influence the quality of streambed habitat.

  9. Cross-sectional transport imaging in a multijunction solar cell

    DOE PAGES

    Haegel, Nancy M.; Ke, Chi -Wen; Taha, Hesham; ...

    2016-12-01

    Here, we combine a highly localized electron-beam point source excitation to generate excess free carriers with the spatial resolution of optical near-field imaging to map recombination in a cross-sectioned multijunction (Ga0.5In0.5P/GaIn0.01As/Ge) solar cell. By mapping the spatial variations in emission of light for fixed generation (as opposed to traditional cathodoluminescence (CL), which maps integrated emission as a function of position of generation), it is possible to directly monitor the motion of carriers and photons. We observe carrier diffusion throughout the full width of the middle (GaInAs) cell, as well as luminescent coupling from point source excitation in the top cellmore » GaInP to the middle cell. Supporting CL and near-field photoluminescence (PL) measurements demonstrate the excitation-dependent Fermi level splitting effects that influence cross-sectioned spectroscopy results, as well as transport limitations on the spatial resolution of conventional cross-sectional far-field measurements.« less

  10. Cross-sectional transport imaging in a multijunction solar cell

    SciTech Connect

    Haegel, Nancy M.; Ke, Chi -Wen; Taha, Hesham; Guthrey, Harvey; Fetzer, Christopher M.; King, Richard R.

    2016-12-01

    Here, we combine a highly localized electron-beam point source excitation to generate excess free carriers with the spatial resolution of optical near-field imaging to map recombination in a cross-sectioned multijunction (Ga0.5In0.5P/GaIn0.01As/Ge) solar cell. By mapping the spatial variations in emission of light for fixed generation (as opposed to traditional cathodoluminescence (CL), which maps integrated emission as a function of position of generation), it is possible to directly monitor the motion of carriers and photons. We observe carrier diffusion throughout the full width of the middle (GaInAs) cell, as well as luminescent coupling from point source excitation in the top cell GaInP to the middle cell. Supporting CL and near-field photoluminescence (PL) measurements demonstrate the excitation-dependent Fermi level splitting effects that influence cross-sectioned spectroscopy results, as well as transport limitations on the spatial resolution of conventional cross-sectional far-field measurements.

  11. Cross-field transport of electrons at the magnetic throat in an annular plasma reactor

    NASA Astrophysics Data System (ADS)

    Zhang, Yunchao; Charles, Christine; Boswell, Rod

    2017-01-01

    Cross-field transport of electrons has been studied at the magnetic throat of the annular Chi-Kung reactor. This annular configuration allows the creation of a low pressure argon plasma with two distinct electron heating locations by independently operating a radio-frequency antenna surrounding the outer source tube, or an antenna housed inside the inner source tube. The two antenna cases show opposite variation trends in radial profiles of electron energy probability function, electron density, plasma potential and electron temperature. The momentum and energy transport coefficients are obtained from the electron energy probability functions, and the related electron fluxes follow the path of electron cooling across the magnetic throat.

  12. Universal relations of transport coefficients from holography

    SciTech Connect

    Cherman, Aleksey; Nellore, Abhinav

    2009-09-15

    We show that there are universal high-temperature relations for transport coefficients of plasmas described by a wide class of field theories with gravity duals. These theories can be viewed as strongly coupled large-N{sub c} conformal field theories deformed by one or more relevant operators. The transport coefficients we study are the speed of sound and bulk viscosity, as well as the conductivity, diffusion coefficient, and charge susceptibility of probe U(1) charges. We show that the sound bound v{sub s}{sup 2}{<=}1/3 is satisfied at high temperatures in these theories and also discuss bounds on the diffusion coefficient, the conductivity, and the bulk viscosity.

  13. Empirical relations between large wood transport and catchment characteristics

    NASA Astrophysics Data System (ADS)

    Steeb, Nicolas; Rickenmann, Dieter; Rickli, Christian; Badoux, Alexandre

    2017-04-01

    The transport of vast amounts of large wood (LW) in water courses can considerably aggravate hazardous situations during flood events, and often strongly affects resulting flood damage. Large wood recruitment and transport are controlled by various factors which are difficult to assess and the prediction of transported LW volumes is difficult. Such information are, however, important for engineers and river managers to adequately dimension retention structures or to identify critical stream cross-sections. In this context, empirical formulas have been developed to estimate the volume of transported LW during a flood event (Rickenmann, 1997; Steeb et al., 2017). The data base of existing empirical wood load equations is, however, limited. The objective of the present study is to test and refine existing empirical equations, and to derive new relationships to reveal trends in wood loading. Data have been collected for flood events with LW occurrence in Swiss catchments of various sizes. This extended data set allows us to derive statistically more significant results. LW volumes were found to be related to catchment and transport characteristics, such as catchment size, forested area, forested stream length, water discharge, sediment load, or Melton ratio. Both the potential wood load and the fraction that is effectively mobilized during a flood event (effective wood load) are estimated. The difference of potential and effective wood load allows us to derive typical reduction coefficients that can be used to refine spatially explicit GIS models for potential LW recruitment.

  14. Barrier Crossing and Transport Activated by Kangaroo Fluctuations

    NASA Astrophysics Data System (ADS)

    Kostur, M.; Luczka, J.

    1999-01-01

    We study barrier crossing of Brownian particles in a bistable symmetric potential and transport of Brownian particles in spatially periodic structures, driven by both kangaroo fluctuations and thermal equilibrium noise of zero mean values. We consider exponentially and algebraically correlated kangaroo fluctuations. Starting with the full Newton--Langevin equation for the Brownian particle and by introducing scaling as well as dimensionless variables, we show that the equation is very well approximated by overdamped dynamics in which inertial effects can be neglected. We analyze properties of selected macroscopic characteristics of the system such as the mean first passage time (MFPT) of particles from one minimum of the bistable potential to the other and mean stationary velocity of particles moving in a spatially periodic potential. In dependence upon statistics of kangaroo fluctuations and temperature of the system, macroscopic characteristics exhibit distinctive non-monotonic behavior. Accordingly, there exist optimal statistics of fluctuations optimizing macroscopic characteristics.

  15. Cross-frontal transport and distribution of ichthyoplankton associated with Chesapeake Bay plume dynamics

    NASA Astrophysics Data System (ADS)

    Reiss, Christian S.; McConaugha, John R.

    1999-02-01

    Cross-frontal transport associated with upwelling conditions was responsible for modifying ichthyoplankton distributions across the inner continental shelf waters off the Chesapeake Bay during late August 1988. Two ichthyoplankton assemblages characteristic of the Chesapeake Bay plume and inner-continental shelf waters were defined using multivariate analysis. Members of the plume assemblage ( Anchoa spp., Menticirrhus spp., and Micropogonias undulatus) were not retained within the Chesapeake Bay plume, but were instead advected 60 km onto the shelf within a low-salinity water mass. A second assemblage, dominated by several shelf-spawned taxa including Etropus microstomus, Prionotus spp. and Centropristis striata was distributed across the shelf. Atlantic croaker, M. undulatus, previously thought to be shelf-spawned exhibited a length-frequency distribution that increased from inshore to offshore, and paralleled that of Anchoa spp. This cross-shelf distribution, and the abundance of small (<3.5 mm), pre-flexion larvae inshore suggests that M. undulatus spawned near the plume front and were subsequently transported offshore with the plume assemblage. A mechanism for rapid cross-frontal transport is described. These findings suggest that the transport and recruitment patterns previously described for this taxon in Chesapeake Bay need to be re-examined. Larval survival and recruitment success of shelf-spawned estuarine species, like M. undulatus, are likely tied to oceanographic conditions on the inner shelf related to upwelling and downwelling conditions and plume dynamics, rather than to simple, wind-driven recruitment mechanisms.

  16. The transport of relative canonical helicity

    SciTech Connect

    You, S.

    2012-09-15

    The evolution of relative canonical helicity is examined in the two-fluid magnetohydrodynamic formalism. Canonical helicity is defined here as the helicity of the plasma species' canonical momentum. The species' canonical helicity are coupled together and can be converted from one into the other while the total gauge-invariant relative canonical helicity remains globally invariant. The conversion is driven by enthalpy differences at a surface common to ion and electron canonical flux tubes. The model provides an explanation for why the threshold for bifurcation in counter-helicity merging depends on the size parameter. The size parameter determines whether magnetic helicity annihilation channels enthalpy into the magnetic flux tube or into the vorticity flow tube components of the canonical flux tube. The transport of relative canonical helicity constrains the interaction between plasma flows and magnetic fields, and provides a more general framework for driving flows and currents from enthalpy or inductive boundary conditions.

  17. 48 CFR 728.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... insurance of transportation or transportation-related services. 728.313 Section 728.313 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 728.313 Contract clauses for insurance of transportation or transportation-related services....

  18. 48 CFR 28.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... insurance of transportation or transportation-related services. 28.313 Section 28.313 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 28.313 Contract clauses for insurance of transportation or transportation-related services....

  19. 48 CFR 28.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... insurance of transportation or transportation-related services. 28.313 Section 28.313 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 28.313 Contract clauses for insurance of transportation or transportation-related services....

  20. 48 CFR 728.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... insurance of transportation or transportation-related services. 728.313 Section 728.313 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 728.313 Contract clauses for insurance of transportation or transportation-related services....

  1. 48 CFR 728.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... insurance of transportation or transportation-related services. 728.313 Section 728.313 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 728.313 Contract clauses for insurance of transportation or transportation-related services....

  2. Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

    ERIC Educational Resources Information Center

    Ruiz, Francisco J.; Luciano, Carmen

    2011-01-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among…

  3. Solar coronal loop heating by cross-field wave transport

    NASA Technical Reports Server (NTRS)

    Amendt, Peter; Benford, Gregory

    1989-01-01

    Solar coronal arches heated by turbulent ion-cyclotron waves may suffer significant cross-field transport by these waves. Nonlinear processes fix the wave-propagation speed at about a tenth of the ion thermal velocity, which seems sufficient to spread heat from a central core into a large cool surrounding cocoon. Waves heat cocoon ions both through classical ion-electron collisions and by turbulent stochastic ion motions. Plausible cocoon sizes set by wave damping are in roughly kilometers, although the wave-emitting core may be only 100 m wide. Detailed study of nonlinear stabilization and energy-deposition rates predicts that nearby regions can heat to values intermediate between the roughly electron volt foot-point temperatures and the about 100 eV core, which is heated by anomalous Ohmic losses. A volume of 100 times the core volume may be affected. This qualitative result may solve a persistent problem with current-driven coronal heating; that it affects only small volumes and provides no way to produce the extended warm structures perceptible to existing instruments.

  4. Isentropic Cross-Tropopause Ozone Transport in the Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    Jing, P.; Cunnold, D. M.; Wang, H. J.; Yang, E.-S.

    2004-01-01

    This paper investigates isentropic ozone exchange between the extratropical lower stratosphere and the subtropical upper troposphere in the Northern Hemisphere. The quantification method is based on the potential vorticity (PV) mapping of Stratospheric Aerosol and Gas Experiment (SAGE)-II ozone measurements and contour advection calculations using the NASA Goddard Space Center Data Assimilation Office (DAO) analysis for the year 1990. The magnitude of the annual isentropic stratosphere-to-troposphere ozone flux is calculated to be approximately twice the flux that is directed from the troposphere into the stratosphere. The net effect is that approx.46 x 10(exp 9) kg/yr of ozone are transferred quasi horizontally from the extratropical lower stratosphere into the subtropical upper troposphere between the isentropic surfaces of 330 and 370 K. The estimated monthly ozone fluxes show that the isentropic cross-tropopause ozone transport is stronger in summer/fall than in winter/ spring, and this seasonality is more obvious at the upper three levels (i.e., 345, 355, and 365 K) than at 335 K. The distributions of the estimated monthly ozone fluxes indicate that the isentropic stratosphere-to-troposphere ozone exchange is associated with wave breaking and occurs preferentially over the eastern Atlantic Ocean and northwest Africa in winter and over the Atlantic and Pacific Oceans in summer.

  5. Isentropic Cross-Tropopause Ozone Transport in the Northern Hemisphere.

    NASA Astrophysics Data System (ADS)

    Jing, P.; Cunnold, D. M.; Wang, H. J.; Yang, E.-S.

    2004-05-01

    This paper investigates isentropic ozone exchange between the extratropical lower stratosphere and the subtropical upper troposphere in the Northern Hemisphere. The quantification method is based on the potential vorticity (PV) mapping of Stratospheric Aerosol and Gas Experiment (SAGE)-II ozone measurements and contour advection calculations using the NASA Goddard Space Center Data Assimilation Office (DAO) analysis for the year 1990. The magnitude of the annual isentropic stratosphere-to-troposphere ozone flux is calculated to be approximately twice the flux that is directed from the troposphere into the stratosphere. The net effect is that 46 × 109 kg yr-1 of ozone are transferred quasi horizontally from the extratropical lower stratosphere into the subtropical upper troposphere between the isentropic surfaces of 330 and 370 K. The estimated monthly ozone fluxes show that the isentropic cross-tropopause ozone transport is stronger in summer/fall than in winter/ spring, and this seasonality is more obvious at the upper three levels (i.e., 345, 355, and 365 K) than at 335 K. The distributions of the estimated monthly ozone fluxes indicate that the isentropic stratosphere-to-troposphere ozone exchange is associated with wave breaking and occurs preferentially over the eastern Atlantic Ocean and northwest Africa in winter and over the Atlantic and Pacific Oceans in summer.


  6. Active transportation and bullying in Canadian schoolchildren: a cross-sectional study.

    PubMed

    Cozma, Ioana; Kukaswadia, Atif; Janssen, Ian; Craig, Wendy; Pickett, William

    2015-02-07

    Bullying is a recognized social problem within child populations. Engagement in childhood bullying often occurs in settings that are away from adult supervision, such as en route to and from school. Bullying episodes may also have a negative impact on school childrens' decisions to engage in active transportation. Using a cross-sectional design, we analyzed reports from the 2009/10 cycle of the Canadian Health Behaviour in School-Aged Children (HBSC) study. Records from this general health survey were obtained for 3,997 urban students in grades 6-10 who lived in close proximity of their school and were hence ineligible for school bussing. Students who indicated walking or bicycling to school were classified as engaged in active transportation. Victims and perpetrators of bullying were defined using standard measures and a frequency cut-off of at least 2-3 times per month. Analyses focused on relations between bullying and active transportation, as well as barriers to active transportation as perceived by young people. 27% of young people indicated being victimized, and 12% indicated that they engaged in bullying. Girls were more likely to be victimized than boys, and younger students were more likely to be victimized than older students. Engagement in active transportation was reported by 63% of respondents, of these, 68% indicated that worrying about bullying on the way to school was an impediment to such transportation methods. Victimization by bullying (adjusted OR = 1.26, 95% CI: 1.00 - 1.59) was reported more frequently by children who used active transportation. Health promotion efforts to promote engagement in active transportation of students to school have obvious value. The potential for modest increases in exposure to bullying should be considered in the planning of such initiatives.

  7. Transportation as a "Related Service": Issues that Involve Transition Activities.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Missouri LINC.

    The paper discusses transportation as a related service for students with disabilities expecially as related to school-to-work transition activities. First, the legislative and legal basis for providing transportation services is discussed in the form of answers to frequently asked questions: why provide transportation? what is the basis for…

  8. Transportation as a "Related Service": Issues that Involve Transition Activities.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Missouri LINC.

    The paper discusses transportation as a related service for students with disabilities expecially as related to school-to-work transition activities. First, the legislative and legal basis for providing transportation services is discussed in the form of answers to frequently asked questions: why provide transportation? what is the basis for…

  9. Cross-shelf transport induced by coastal trapped waves along the coast of East China Sea

    NASA Astrophysics Data System (ADS)

    Jiang, Lin; Dong, Changming; Yin, Liping

    2017-08-01

    Cross-shelf transport is important due to its role in the transport of nutrients, larvae, sediments, and pollutants. The role of coastal trapped waves (CTWs) and their contribution to the cross-shelf transport is presently unknown. The impact of wind-driven CTWs on the structure of the cross-shelf currents and transport is investigated in the East China Sea (ECS) starting from theory. The cross-shelf currents are divided into four terms: the geostrophic balance (GB) term, the second-order wave (SOW) term, the bottom friction (BF) term and Ekman (EK) term, as well as three modes: the Kelvin wave (KW) mode, the first shelf wave (SW1) mode and the second shelf wave (SW2) mode. Comparison among these decompositions shows that (1) for the four terms, the effect of the GB and EK terms is continual, while that of the BF term is confined to 60u2013240 km offshore, and the contribution of the SOW term can be ignored; (2) for the three modes, the KW and SW1 modes are dominant in cross-shelf transport. The results show that the total cross-shelf transport travels onshore under idealized wind stress on the order of 10-1, and it increases along the cross-shelf direction and peaks about -0.73 Sv at the continental shelf margin. With the increase of linear bottom friction coefficient, the cross-shelf transport declines with distance with the slope becoming more uniform.

  10. Traffic control devices, visibility, and railroad grade crossings. Transportation research record

    SciTech Connect

    1995-12-31

    The papers contained in this volume are primarily from the 74th Annual Meeting of the Transportation Research Board and the Symposium for Improving Visibility for the Night Traveler, which was held in May 1994 in Washington, D.C. They concern traffic signs and signals, highway visibility, and rail-highway grade crossing safety and research, addressing some of the problems and issues facing urban engineers as they grapple with the ever more complex traffic system. Readers with a specific interest in traffic control devices will find papers related to effective uses of variable message signs, comprehension of various types of traffic control devices and their effects on driver behavior, pedestrian crosswalk time requirements, and empirical analysis of two-way stop-controlled intersections. Readers with an interest in delineation and illumination will find papers on minimum retroreflectivity requirements, pavement marking visibility and detectability, curve delineation, traffic sign reading distances at night, and apparent nighttime color of pavement marking products. Closing out this Record are papers addressing the application of GIS to rail-highway crossing safety and the accuracy of U.S. Department of Transportation rail-highway grade crossing accident prediction models.

  11. Projecting Labor Requirements for Transportation-Related Construction. Final Report.

    ERIC Educational Resources Information Center

    Washington Technical Inst., Washington, DC. Center for Urban Services.

    This report examines the urban transportation planning process and its labor market impact, including projections of opportunities for minority participation in construction, operation, and maintenance of a transportation system and forecasts of training needed in critical occupations. It was found that transportation-related construction may be…

  12. Cross-shore sand transport by infragravity waves as a function of beach steepness

    NASA Astrophysics Data System (ADS)

    Bakker, A. T. M.; Brinkkemper, J. A.; Steen, F.; Tissier, M. F. S.; Ruessink, B. G.

    2016-10-01

    Two field data sets of near-bed velocity, pressure, and sediment concentration are analyzed to study the influence of infragravity waves on sand suspension and cross-shore transport. On the moderately sloping Sand Motor beach (≈1:35), the local ratio of infragravity wave height to sea-swell wave height is relatively small (HIG/HSW<0.4), and sand fluxes are related to the correlation of the infragravity-wave orbital motion with the sea-swell wave envelope, r0. When the largest sea-swell waves are present during negative infragravity velocities (bound wave, negative correlation r0), most sand is suspended here, and the infragravity sand flux qIG is offshore. When r0 is positive, the largest sea-swell waves are present during positive infragravity velocities (free wave), and qIG is onshore directed. For both cases, the infragravity contribution to the total sand flux is, however, relatively small (<20%). In the inner surf zone of the gently (≈1:80) sloping Ameland beach, the infragravity waves are relatively large (HIG/HSW>0.4), most sand is suspended during negative infragravity velocities, and qIG is offshore directed. The infragravity contribution to the total sand flux is considerably larger and reaches up to ≈60% during energetic conditions. On the whole, HIG/HSW is a good indicator for the infragravity-related sand suspension mechanism and the resulting infragravity sand transport direction and relative importance.

  13. Performance of a Cross-Flow Humidifier with a High Flux Water Vapor Transport Membrane

    SciTech Connect

    Ahluwalia, R. K.; Wang, X.; Johnson, W. B.; Berg, F.; Kadylak, D.

    2015-09-30

    Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flow humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.

  14. Performance of a cross-flow humidifier with a high flux water vapor transport membrane

    NASA Astrophysics Data System (ADS)

    Ahluwalia, R. K.; Wang, X.; Johnson, W. B.; Berg, F.; Kadylak, D.

    2015-09-01

    Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flow humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.

  15. Prospects for cost reductions from relaxing additional cross-border measures related to livestock trade.

    PubMed

    Hop, G E; Mourits, M C M; Slager, R; Oude Lansink, A G J M; Saatkamp, H W

    2013-05-01

    Compared with the domestic trade in livestock, intra-communal trade across the European Union (EU) is subject to costly, additional veterinary measures. Short-distance transportation just across a border requires more measures than long-distance domestic transportation, while the need for such additional cross-border measures can be questioned. This study examined the prospects for cost reductions from relaxing additional cross-border measures related to trade within the cross-border region of the Netherlands (NL) and Germany (GER); that is, North Rhine Westphalia and Lower Saxony. The study constructed a deterministic spread-sheet cost model to calculate the costs of both routine veterinary measures (standard measures that apply to both domestic and cross-border transport) and additional cross-border measures (extra measures that only apply to cross-border transport) as applied in 2010. This model determined costs by stakeholder, region and livestock sector, and studied the prospects for cost reduction by calculating the costs after the relaxation of additional cross-border measures. The selection criteria for relaxing these measures were (1) a low expected added value on preventing contagious livestock diseases, (2) no expected additional veterinary risks in case of relaxation of measures and (3) reasonable cost-saving possibilities. The total cost of routine veterinary measures and additional cross-border measures for the cross-border region was €22.1 million, 58% (€12.7 million) of which came from additional cross-border measures. Two-thirds of this €12.7 million resulted from the trade in slaughter animals. The main cost items were veterinary checks on animals (twice in the case of slaughter animals), export certification and control of export documentation. Four additional cross-border measures met the selection criteria for relaxation. The relaxation of these measures could save €8.2 million (€5.0 million for NL and €3.2 million for GER) annually

  16. Plant water relations I: uptake and transport

    USDA-ARS?s Scientific Manuscript database

    Plants, like all living things, are mostly water. Water is the matrix of life, and its availability determines the distribution and productivity of plants on earth. Vascular plants evolved structures that enable them to transport water long distances with little input of energy, but the hollow trach...

  17. Neighbourhood environment, sitting time and motorised transport in older adults: a cross-sectional study in Hong Kong

    PubMed Central

    Barnett, Anthony; Cerin, Ester; Ching, Claudia S-K; Johnston, Janice M; Lee, Ruby S Y

    2015-01-01

    Objectives Sitting time is a public health concern. This study examined associations of objectively measured neighbourhood environmental attributes with non-transport sitting time and motorised transport in 484 Hong Kong older adults. Neighbourhood attributes encouraging walking may help older adults replace some sitting time at home and on motorised transport with light-to-moderate-intensity activities such as strolling around the neighbourhood or walking to/from neighbourhood destinations. Thus, we hypothesised environmental attributes found to be related to walking would show associations with non-transport sitting time and motorised transport opposite to those seen for walking. Design Cross-sectional. Setting Hong Kong, an ultradense urban environment. Participants 484 ethnic Chinese Hong Kong residents aged 65+ recruited from membership lists of four Hong Kong Elderly Health Centres representing catchment areas of low and high transport-related walkability stratified by socioeconomic status (response rate: 78%). Primary and secondary outcome measures Attributes of participants’ neighbourhood environments were assessed by environmental audits, while non-transport sitting time and motorised transport were ascertained using the International Physical Activity Questionnaire—Long Form (Chinese version). Results Daily non-transport sitting minutes were 283 (SD=128) and motorised transport 23 (SD=28). Prevalence of signs of crime/disorder, streetlights, public facilities (toilets and benches) and pedestrian safety were independently negatively related, and sloping streets positively related, to sitting outcomes. Places of worship in the neighbourhood were predictive of more, and prevalence of public transit points of less, non-transport sitting. Associations of either or both sitting outcomes with prevalence of food/grocery stores and presence of parks were moderated by path obstructions and signs of crime/disorder. Conclusions The findings suggest that access to

  18. Supercritical droplet combustion and related transport phenomena

    NASA Technical Reports Server (NTRS)

    Yang, Vigor; Hsieh, K. C.; Shuen, J. S.

    1993-01-01

    An overview of recent advances in theoretical analyses of supercritical droplet vaporization and combustion is conducted. Both hydrocarbon and cryogenic liquid droplets over a wide range of thermodynamic states are considered. Various important high-pressure effects on droplet behavior, such as thermodynamic non-ideality, transport anomaly, and property variation, are reviewed. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influence on fluid transport, gas-liquid interfacial thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibit a considerable change in the combustion mechanism at the criticl pressure, mainly as a result of reduced mass diffusivity and latent heat of vaporization with increased pressure. The influence of droplet size on the burning characteristics is also noted.

  19. Supercritical droplet combustion and related transport phenomena

    NASA Technical Reports Server (NTRS)

    Yang, Vigor; Hsieh, K. C.; Shuen, J. S.

    1993-01-01

    An overview of recent advances in theoretical analyses of supercritical droplet vaporization and combustion is conducted. Both hydrocarbon and cryogenic liquid droplets over a wide range of thermodynamic states are considered. Various important high-pressure effects on droplet behavior, such as thermodynamic non-ideality, transport anomaly, and property variation, are reviewed. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influence on fluid transport, gas-liquid interfacial thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibit a considerable change in the combustion mechanism at the criticl pressure, mainly as a result of reduced mass diffusivity and latent heat of vaporization with increased pressure. The influence of droplet size on the burning characteristics is also noted.

  20. BOXER: Fine-flux Cross Section Condensation, 2D Few Group Diffusion and Transport Burnup Calculations

    SciTech Connect

    2010-02-01

    Neutron transport, calculation of multiplication factor and neutron fluxes in 2-D configurations: cell calculations, 2-D diffusion and transport, and burnup. Preparation of a cross section library for the code BOXER from a basic library in ENDF/B format (ETOBOX).

  1. Kinetic Phenomena in Transport of Electrons and Positrons in Gases caused by the Properties of Scattering Cross Sections

    NASA Astrophysics Data System (ADS)

    Petrović, Zoran Lj; Marjanović, Srdan; Dujko, Saša; Banković, Ana; Šašić, Olivera; Bošnjaković, Danko; Stojanović, Vladimir; Malović, Gordana; Buckman, Stephen; Garcia, Gustavo; White, Ron; Sullivan, James; Brunger, Michael

    2014-04-01

    Collisions of electrons, atoms, molecules, photons and ions are the basic processes in plasmas and ionized gases in general. This is especially valid for low temperature collisional plasmas. Kinetic phenomena in transport are very sensitivitive to the shape of the cross sections and may at the same time affect the macroscopic applications. We will show how transport theory or simulation codes, phenomenology, kinetic phenomena and transport data may be used to improve our knowledge of the cross sections, our understanding of the plasma models, application of the swarm physics in ionized gases and similar applications to model and improve gas filled traps of positrons. Swarm techniques could also be a starting point in applying atomic and molecular data in models of electron or positron therapy/diagnostics in radiation related medicine.

  2. Differential Cross Section Kinematics for 3-dimensional Transport Codes

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank

    2008-01-01

    In support of the development of 3-dimensional transport codes, this paper derives the relevant relativistic particle kinematic theory. Formulas are given for invariant, spectral and angular distributions in both the lab (spacecraft) and center of momentum frames, for collisions involving 2, 3 and n - body final states.

  3. Relating Reactive Transport to Hierarchical Sedimentary Architecture. Part 1. Horizontal Spatial Correlation of Hydraulic and Reactive Transport Parameters

    NASA Astrophysics Data System (ADS)

    Ritzi, R. W., Jr.

    2014-12-01

    A number of studies of the spatial correlation of log permeability (Y) in different sedimentary aquifers are reviewed showing that the spatial correlation structure can be defined by how the proportion of lag transitions crossing different facies (i.e. the cross-transition probability structure) increases with increasing lag distance. The common underlying cross-transition structure can contain substructures with different correlation ranges corresponding to different scales of sedimentary facies within the hierarchy of the sedimentary architecture. For each substructure, the standard deviation in facies length relative to the mean can mostly define the shape, and the proportions and mean length of facies define the range. An illustrative example from the Borden research site shows the horizontal spatial bivariate correlation of Y and of reactive attributes (R) affecting subsurface transport are both defined by the same underlying cross-transition probability structures. Thus, the horizontal Y and R autosemivariograms and the R-Y cross-semivariogram have the same underlying composite correlation structure and substructures (shape and range in the rise to a sill). Such cross-transition probability based correlation structures are used in the companion Part 2 presentation (Soltanian et al.) to develop models which relate the time-dependent effective retardation and the particle displacement variance to hierarchical sedimentary architecture.

  4. Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography.

    PubMed

    Freire, Laila Gonzales; Gavini, Giulio; Cunha, Rodrigo Sanches; Santos, Marcelo dos

    2012-01-01

    The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

  5. Models of cross shelf transport introduced by the Lofoten Maelstrom

    NASA Astrophysics Data System (ADS)

    Ommundsen, A.

    2002-01-01

    The drift of particles released in the tidal current (Moskstraumen) near Lofotodden, located at 67°50'N, 12°50'E, has been studied. The periodical tidal current combined with a background current is found to introduce a transport between Vestfjorden inside Lofotodden and the shelf outside. This particular transport may be important for the drift of cod eggs, larvae and other important biological and chemical tracers. A fine-resolution numerical model provided the Eulerian tidal current field based on which the particle trajectories are calculated using a Lagrangian particle tracking technique. The tracking algorithm was extended by a random-walk method to simulate small scale turbulence. An idealized current model of the area is also developed for use as a simplification tool to reveal the basic mechanisms of the drift and to demonstrate the sensibility of time stepping in numerical integration.

  6. Critical care transportation by paramedics: a cross-sectional survey.

    PubMed

    Raynovich, William; Hums, Jason; Stuhlmiller, David F; Bramble, James D; Kasha, Ted; Galt, Kim

    2013-01-01

    The purpose of this study was to gather data from paramedics practicing in the critical care transport setting to guide development of the education, training, and clinical practices for certification as a critical care paramedic. A paper survey of 1991 randomly selected nationally registered (NREMT) paramedics was conducted. Nine paramedics with residences in small US Pacific Island territories were not included in the survey. We received 610 responses (30.6%). Respondents that stated that they provided critical care transport services reported using pediatric skills and equipment the most and intracranial pressure monitoring the least. Paramedics served as the primary provider for pediatric patients (72.5%), 12-lead electrocardiogram (66.3%), intravenous infusion pump (76.7%), mechanical ventilator (66.9%), central line management (63.1%), and chest tube management (63.3%). Paramedics served in a team member capacity most often with neonatal isolette (71.8%), intra-aortic balloon pump (79.2%), and ICP monitoring (64.9%). The majority provided ground critical care transport (249) compared to 44 rotor-wing and 6 fixed-wing. Sixteen respondents reported serving as primary providers on combinations of ground, rotor-, and fixed-wing services. Paramedics reported being the primary provider on the critical care transport team and performing skills while using equipment and administering medications that exceeded their education and training as paramedic and, at times, without the benefit of any additional education or training. National appreciation of this reality should spur development of standardized education, licensing or certification, and continuing education to prepare paramedics for their role as critical care medical providers. Copyright © 2013 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.

  7. Cross-field transport in Goldreich-Sridhar magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Fraschetti, F.

    2016-01-01

    I derive analytically the temporal dependence of the perpendicular transport coefficient of a charged particle in the three-dimensional anisotropic turbulence conjectured by Goldreich-Sridhar by implementing multispacecraft constraints on the turbulence power spectrum. The particle motion away from the turbulent local field line is assessed as gradient-curvature drift of the guiding center and compared with the magnetic field line random walk. At inertial scales much smaller than the turbulence outer scale, particles decorrelate from field lines in a free-streaming motion, with no diffusion. In the solar wind at 1 AU, for energy sufficiently small (<1 keV protons), the perpendicular average displacement due to field line tangling generally dominates over two decades of turbulent scales. However, for higher energies (≃25 MeV protons) within the range of multispacecraft measurements, the longitudinal spread originating from transport due to gradient-curvature drift reaches up to ≃10∘ -20∘. This result highlights the role of perpendicular transport in the interpretation of interplanetary and interstellar data.

  8. Illegal pedestrian crossing at signalised intersections: incidence and relative risk.

    PubMed

    King, Mark J; Soole, David; Ghafourian, Ameneh

    2009-05-01

    Illegal pedestrian behaviour is common and is reported as a factor in many pedestrian crashes. Since walking is being promoted for its health and environmental benefits, minimisation of its associated risks is of interest. The risk associated with illegal road crossing is unclear, and better information would assist in setting a rationale for enforcement and priorities for public education. An observation survey of pedestrian behaviour was conducted at signalised intersections in the Brisbane CBD (Queensland, Australia) on typical workdays, using behavioural categories that were identifiable in police crash reports. The survey confirmed high levels of crossing against the lights, or close enough to the lights that they should legally have been used. Measures of exposure for crossing legally, against the lights, and close to the lights were generated by weighting the observation data. Relative risk ratios were calculated for these categories using crash data from the observation sites and adjacent midblocks. Crossing against the lights and crossing close to the lights both exhibited a crash risk per crossing event approximately eight times that of legal crossing at signalised intersections. The implications of these results for enforcement and education are discussed, along with the limitations of the study.

  9. Resonant charge exchange and relevant transport cross sections for excited states of oxygen and nitrogen atoms

    SciTech Connect

    Eletskii, A.V.; Capitelli, M.; Celiberto, R.; Laricchiuta, A.

    2004-04-01

    Resonant charge-exchange cross sections and the relevant transport (diffusion) cross sections for excited states of nitrogen and oxygen atoms have been calculated. The calculation is performed using the asymptotic approach, based on the single-electron asymptotic representation of the electron wave function. The ground-state cross sections are in a good agreement with those calculated via comprehensive quantum chemical approach. The results of calculations demonstrate a reasonable accuracy and a high convenience of this approach in determination of cross sections for the manifold of excited states of atoms.

  10. Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

    PubMed Central

    Ruiz, Francisco J; Luciano, Carmen

    2011-01-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among separate relational networks and by correlating participants' performance with a standard measure of analogical reasoning. In two experiments, adult participants first completed general intelligence and analogical reasoning tests. Subsequently, they were exposed to a computerized conditional discrimination training procedure designed to create two relational networks, each consisting of two 3-member equivalence classes. The critical test was a two-part analogical test in which participants had to relate combinatorial relations of coordination and distinction between the two relational networks. In Experiment 1, combinatorial relations for each network were individually tested prior to analogical testing, but in Experiment 2 they were not. Across both experiments, 65% of participants passed the analogical test on the first attempt. Moreover, results from the training procedure were strongly correlated with the standard measure of analogical reasoning. PMID:21547072

  11. Cross-domain analogies as relating derived relations among two separate relational networks.

    PubMed

    Ruiz, Francisco J; Luciano, Carmen

    2011-05-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among separate relational networks and by correlating participants' performance with a standard measure of analogical reasoning. In two experiments, adult participants first completed general intelligence and analogical reasoning tests. Subsequently, they were exposed to a computerized conditional discrimination training procedure designed to create two relational networks, each consisting of two 3-member equivalence classes. The critical test was a two-part analogical test in which participants had to relate combinatorial relations of coordination and distinction between the two relational networks. In Experiment 1, combinatorial relations for each network were individually tested prior to analogical testing, but in Experiment 2 they were not. Across both experiments, 65% of participants passed the analogical test on the first attempt. Moreover, results from the training procedure were strongly correlated with the standard measure of analogical reasoning.

  12. Noninvasive cross section reconstruction with transport theory constraints

    SciTech Connect

    Fredette, N.; Ragusa, J.; Bangerth, W.

    2012-07-01

    We consider the inverse problem of identifying the spatially variable absorption and scattering properties of a medium by measuring the exiting radiation when the body is actively interrogated. We formulate this inverse problem as a PDE-constrained optimization problem and solve it iteratively with Newton's method. The constraint is given by the radiative transport equation for neutral particles. Two examples are considered. The first is a dual inclusion domain with no scattering. This problem explores the convergence patterns of the method. The second problem is a central inclusion problem with scattering. This problem explores the optical thickness limit of the method. This optical thickness was determined to be 2-3 mean free paths. (authors)

  13. Investigation of cross-linking characteristics of novel hole-transporting materials for solution-processed phosphorescent OLEDs

    NASA Astrophysics Data System (ADS)

    Lee, Jaemin; Ameen, Shahid; Lee, Changjin

    2016-04-01

    After the success of commercialization of the vacuum-evaporated organic light-emitting diodes (OLEDs), solutionprocessing or printing of OLEDs are currently attracting much research interests. However, contrary to various kinds of readily available vacuum-evaporable OLED materials, the solution-processable OLED materials are still relatively rare. Hole-transporting layer (HTL) materials for solution-processed OLEDs are especially limited, because they need additional characteristics such as cross-linking to realize multilayer structures in solution-processed OLEDs, as well as their own electrically hole-transporting characteristics. The presence of such cross-linking characteristics of solutionprocessable HTL materials therefore makes them more challenging in the development stage, and also makes them essence of solution-processable OLED materials. In this work, the structure-property relationships of thermally crosslinkable HTL materials were systematically investigated by changing styrene-based cross-linking functionalities and modifying the carbazole-based hole-transporting core structures. The temperature dependency of the cross-linking characteristics of the HTL materials was systematically investigated by the UV-vis. absorption spectroscopy. The new HTL materials were also applied to green phosphorescent OLEDs, and their device characteristics were also investigated based on the chemical structures of the HTL materials. The device configuration was [ITO / PEDOT:PSS / HTL / EML / ETL / CsF / Al]. We found out that the chemical structures of the cross-linking functionalities greatly affect not only the cross-linking characteristics of the resultant HTL materials, but also the resultant OLED device characteristics. The increase of the maximum luminance and efficiency of OLEDs was evident as the cross-linking temperature decreases from higher than 200°C to at around 150°C.

  14. 48 CFR 728.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses for insurance of transportation or transportation-related services. 728.313 Section 728.313 Federal Acquisition...) USAID is required by law to include language in all its direct contracts and subcontracts ensuring that...

  15. Exploring safety impacts of pedestrian-crossing configurations at signalized junctions on urban roads with public transport routes.

    PubMed

    Gitelman, Victoria; Carmel, Roby; Doveh, Etti; Hakkert, Shalom

    2017-04-07

    This study explored the impacts of pedestrian-crossing configurations and other design features, on accident occurrences at signalized junctions situated on central public transport routes (PTRs) of urban arterials. Statistical tests and negative-binomial regression models were applied to identify factors affecting accidents and to examine accident numbers of the PTR junctions as opposed to comparison-sites. At the PTR junctions, a consistent impact of pedestrian-crossing configurations on accidents was found, where a gradated-crossing with mixed-shifting is the least safe. Four-legged junctions tend to higher accident numbers relative to the three-legged junctions. PTR junctions are characterized by higher accident numbers, related to comparison-sites, when controlling for other design characteristics. The study findings may assist in selecting preferable design solutions while planning PTR.

  16. A Comparison of Hyporheic Transport at a Cross-Vane Structure and Natural Riffle.

    PubMed

    Smidt, Samuel J; Cullin, Joseph A; Ward, Adam S; Robinson, Jesse; Zimmer, Margaret A; Lautz, Laura K; Endreny, Theodore A

    2015-01-01

    While restoring hyporheic flowpaths has been cited as a benefit to stream restoration structures, little documentation exists confirming that constructed restoration structures induce comparable hyporheic exchange to natural stream features. This study compares a stream restoration structure (cross-vane) to a natural feature (riffle) concurrently in the same stream reach using time-lapsed electrical resistivity (ER) tomography. Using this hydrogeophysical approach, we were able to quantify hyporheic extent and transport beneath the cross-vane structure and the riffle. We interpret from the geophysical data that the cross-vane and the natural riffle induced spatially and temporally unique hyporheic extent and transport, and the cross-vane created both spatially larger and temporally longer hyporheic flowpaths than the natural riffle. Tracer from the 4.67-h injection was detected along flowpaths for 4.6 h at the cross-vane and 4.2 h at the riffle. The spatial extent of the hyporheic zone at the cross-vane was 12% larger than that at the riffle. We compare ER results of this study to vertical fluxes calculated from temperature profiles and conclude significant differences in the interpretation of hyporheic transport from these different field techniques. Results of this study demonstrate a high degree of heterogeneity in transport metrics at both the cross-vane and the riffle and differences between the hyporheic flowpath networks at the two different features. Our results suggest that restoration structures may be capable of creating sufficient exchange flux and timescales of transport to achieve the same ecological functions as natural features, but engineering of the physical and biogeochemical environment may be necessary to realize these benefits.

  17. Neutron cross-section probability tables in TRIPOLI-3 Monte Carlo transport code

    SciTech Connect

    Zheng, S.H.; Vergnaud, T.; Nimal, J.C.

    1998-03-01

    Neutron transport calculations need an accurate treatment of cross sections. Two methods (multi-group and pointwise) are usually used. A third one, the probability table (PT) method, has been developed to produce a set of cross-section libraries, well adapted to describe the neutron interaction in the unresolved resonance energy range. Its advantage is to present properly the neutron cross-section fluctuation within a given energy group, allowing correct calculation of the self-shielding effect. Also, this PT cross-section representation is suitable for simulation of neutron propagation by the Monte Carlo method. The implementation of PTs in the TRIPOLI-3 three-dimensional general Monte Carlo transport code, developed at Commissariat a l`Energie Atomique, and several validation calculations are presented. The PT method is proved to be valid not only in the unresolved resonance range but also in all the other energy ranges.

  18. Ab initio electron scattering cross-sections and transport in liquid xenon

    NASA Astrophysics Data System (ADS)

    Boyle, G. J.; McEachran, R. P.; Cocks, D. G.; Brunger, M. J.; Buckman, S. J.; Dujko, S.; White, R. D.

    2016-09-01

    Ab initio fully differential cross-sections for electron scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework (Boyle et al 2015 J. Chem. Phys. 142 154507) which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann’s equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10-4-1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculations.

  19. Do buoyant plumes enhance cross-shelf transport in the Black Sea?

    NASA Astrophysics Data System (ADS)

    Sedakov, Roman; Zavialov, Peter; Izhitsky, Alexander

    2017-04-01

    Like many inland seas, the Black Sea is exposed to massive continental discharges on the one hand and significant anthropogenic stresses, including pollution, on the other. It is, therefore, important to understand mechanisms of advection of continental water into the sea and factors that may influence transport of such water across shelf areas. In this study, we focus on the coastal segment of the Black Sea between the Feodosia Bay, which includes nature reserve and resort areas, and the Kerch Strait. The Sea of Azov outflow penetrates into the Black Sea through the latter, forming a plume of relatively fresh, light waters with elevated concentrations of suspended matter but also pollutants, especially hydrocarbons. This plume, which can be detected via satellite imagery of the region, extends on over 70 km from the Kerch Strait outfall along Crimea shore and reaches the Feodosia Bay, making that area the most polluted of the Crimea shoreline. In situ velocity measurements were conducted at a mooring station deployed in the area at the depth of 5 and 21.5 meters during the period 17th-23rd of May 2015. These data demonstrated high correlation of the wind stress with the cross-shore component of the velocity in the surface layer and anti-correlation with that in the bottom layer during the periods when a two-layered stratification of the water column due to the occurrence of the Azov plume was present, and lack of such correlation otherwise. In order to investigate whether the buoyant plume in the surface layer is capable of fortifying the wind-driven cross-shelf exchanges, we develop a dynamical model of current forming under the influence of wind tension, pressure gradient and Earth's rotation in a simple one- and a two- layer setups. Firstly, a 2D model was investigated that did not account Coriolis effect. Secondly, a 3D model with Coriolis effect was investigated. The main parameter of the problem is the eddy diffusivity coefficient, which we choose to be

  20. Influence of structural properties on ballistic transport in nanoscale epitaxial graphene cross junctions.

    PubMed

    Bock, Claudia; Weingart, Sonja; Karaissaridis, Epaminondas; Kunze, Ulrich; Speck, Florian; Seyller, Thomas

    2012-10-05

    In this paper we investigate the influence of material and device properties on the ballistic transport in epitaxial monolayer graphene and epitaxial quasi-free-standing monolayer graphene. Our studies comprise (a) magneto-transport in two-dimensional (2D) Hall bars, (b) temperature- and magnetic-field-dependent bend resistance of unaligned and step-edge-aligned orthogonal cross junctions, and (c) the influence of the lead width of the cross junctions on ballistic transport. We found that ballistic transport is highly sensitive to scattering at the step edges of the silicon carbide substrate. A suppression of the ballistic transport is observed if the lead width of the cross junction is reduced from 50 nm to 30 nm. In a 50 nm wide device prepared on quasi-free-standing graphene we observe a gradual transition from the ballistic into the diffusive transport regime if the temperature is increased from 4.2 to about 50 K, although 2D Hall bars show a temperature-independent mobility. Thus, in 1D devices additional temperature-dependent scattering mechanisms play a pivotal role.

  1. Human membrane transporter database: a Web-accessible relational database for drug transport studies and pharmacogenomics.

    PubMed

    Yan, Q; Sadée, W

    2000-01-01

    The human genome contains numerous genes that encode membrane transporters and related proteins. For drug discovery, development, and targeting, one needs to know which transporters play a role in drug disposition and effects. Moreover, genetic polymorphisms in human membrane transporters may contribute to interindividual differences in the response to drugs. Pharmacogenetics, and, on a genome-wide basis, pharmacogenomics, address the effect of genetic variants on an individual's response to drugs and xenobiotics. However, our knowledge of the relevant transporters is limited at present. To facilitate the study of drug transporters on a broad scale, including the use of microarray technology, we have constructed a human membrane transporter database (HMTD). Even though it is still largely incomplete, the database contains information on more than 250 human membrane transporters, such as sequence, gene family, structure, function, substrate, tissue distribution, and genetic disorders associated with transporter polymorphisms. Readers are invited to submit additional data. Implemented as a relational database, HMTD supports complex biological queries. Accessible through a Web browser user interface via Common Gateway Interface (CGI) and Java Database Connection (JDBC), HMTD also provides useful links and references, allowing interactive searching and downloading of data. Taking advantage of the features of an electronic journal, this paper serves as an interactive tutorial for using the database, which we expect to develop into a research tool.

  2. Transport of Magnesium by a Bacterial Nramp-Related Gene

    PubMed Central

    Rodionov, Dmitry A.; Freedman, Benjamin G.; Senger, Ryan S.; Winkler, Wade C.

    2014-01-01

    Magnesium is an essential divalent metal that serves many cellular functions. While most divalent cations are maintained at relatively low intracellular concentrations, magnesium is maintained at a higher level (∼0.5–2.0 mM). Three families of transport proteins were previously identified for magnesium import: CorA, MgtE, and MgtA/MgtB P-type ATPases. In the current study, we find that expression of a bacterial protein unrelated to these transporters can fully restore growth to a bacterial mutant that lacks known magnesium transporters, suggesting it is a new importer for magnesium. We demonstrate that this transport activity is likely to be specific rather than resulting from substrate promiscuity because the proteins are incapable of manganese import. This magnesium transport protein is distantly related to the Nramp family of proteins, which have been shown to transport divalent cations but have never been shown to recognize magnesium. We also find gene expression of the new magnesium transporter to be controlled by a magnesium-sensing riboswitch. Importantly, we find additional examples of riboswitch-regulated homologues, suggesting that they are a frequent occurrence in bacteria. Therefore, our aggregate data discover a new and perhaps broadly important path for magnesium import and highlight how identification of riboswitch RNAs can help shed light on new, and sometimes unexpected, functions of their downstream genes. PMID:24968120

  3. Transport of magnesium by a bacterial Nramp-related gene.

    PubMed

    Shin, Jung-Ho; Wakeman, Catherine A; Goodson, Jonathan R; Rodionov, Dmitry A; Freedman, Benjamin G; Senger, Ryan S; Winkler, Wade C

    2014-06-01

    Magnesium is an essential divalent metal that serves many cellular functions. While most divalent cations are maintained at relatively low intracellular concentrations, magnesium is maintained at a higher level (∼0.5-2.0 mM). Three families of transport proteins were previously identified for magnesium import: CorA, MgtE, and MgtA/MgtB P-type ATPases. In the current study, we find that expression of a bacterial protein unrelated to these transporters can fully restore growth to a bacterial mutant that lacks known magnesium transporters, suggesting it is a new importer for magnesium. We demonstrate that this transport activity is likely to be specific rather than resulting from substrate promiscuity because the proteins are incapable of manganese import. This magnesium transport protein is distantly related to the Nramp family of proteins, which have been shown to transport divalent cations but have never been shown to recognize magnesium. We also find gene expression of the new magnesium transporter to be controlled by a magnesium-sensing riboswitch. Importantly, we find additional examples of riboswitch-regulated homologues, suggesting that they are a frequent occurrence in bacteria. Therefore, our aggregate data discover a new and perhaps broadly important path for magnesium import and highlight how identification of riboswitch RNAs can help shed light on new, and sometimes unexpected, functions of their downstream genes.

  4. Seasonal and interannual variability of cross-shelf transports of chlorophyll in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Martínez-López, Benjamín; Zavala-Hidalgo, Jorge

    2009-04-01

    The seasonal and interannual variability of offshore cross-shelf transports of chlorophyll-rich waters in the Gulf of Mexico is studied using Level-3, monthly SeaWiFS data and monthly NCEP/NCAR-Reanalysis winds for the period September 1997-August 2007. Offshore cross-shelf transports of chlorophyll-rich waters have a seasonal cycle mainly modulated by the component of the wind field along the coast. These transports are basically located at three regions: southwest of the Texas-Louisiana (LATEX) Shelf, the southern Bay of Campeche, and southeast of the Mississippi River mouth. Southwest of the LATEX Shelf and in the southern Bay of Campeche, the confluence of seasonal along-coast currents, produced by the convergence of the seasonal along-coast wind stress component, induces offshore cross-shelf transport of chlorophyll-rich waters, with maximum values of chlorophyll- a concentration occurring at these locations during May and October-November, respectively. On the slope, southeast of the Mississippi River mouth, the seasonal maximum of chlorophyll- a concentration is observed in July due to the prevailing southwesterly winds during this month. A large fraction of the interannual variability of the offshore cross-shelf transports of chlorophyll-rich waters in the southern Bay of Campeche is explained by anomalies of the convergence of the along-coast wind stress component. On the southwestern LATEX Shelf, in addition to this process, cyclonic and anticyclonic eddies reaching this region may contribute to the interannual variability by shifting the location of the offshore cross-shelf transports.

  5. Neighbourhood environment, sitting time and motorised transport in older adults: a cross-sectional study in Hong Kong.

    PubMed

    Barnett, Anthony; Cerin, Ester; Ching, Claudia S-K; Johnston, Janice M; Lee, Ruby S Y

    2015-05-03

    Sitting time is a public health concern. This study examined associations of objectively measured neighbourhood environmental attributes with non-transport sitting time and motorised transport in 484 Hong Kong older adults. Neighbourhood attributes encouraging walking may help older adults replace some sitting time at home and on motorised transport with light-to-moderate-intensity activities such as strolling around the neighbourhood or walking to/from neighbourhood destinations. Thus, we hypothesised environmental attributes found to be related to walking would show associations with non-transport sitting time and motorised transport opposite to those seen for walking. Cross-sectional. Hong Kong, an ultradense urban environment. 484 ethnic Chinese Hong Kong residents aged 65+ recruited from membership lists of four Hong Kong Elderly Health Centres representing catchment areas of low and high transport-related walkability stratified by socioeconomic status (response rate: 78%). Attributes of participants' neighbourhood environments were assessed by environmental audits, while non-transport sitting time and motorised transport were ascertained using the International Physical Activity Questionnaire-Long Form (Chinese version). Daily non-transport sitting minutes were 283 (SD=128) and motorised transport 23 (SD=28). Prevalence of signs of crime/disorder, streetlights, public facilities (toilets and benches) and pedestrian safety were independently negatively related, and sloping streets positively related, to sitting outcomes. Places of worship in the neighbourhood were predictive of more, and prevalence of public transit points of less, non-transport sitting. Associations of either or both sitting outcomes with prevalence of food/grocery stores and presence of parks were moderated by path obstructions and signs of crime/disorder. The findings suggest that access to specific destinations and relatively low-cost, minimal impact modifications to the urban form, such

  6. Transport Mechanisms of Solid Lipid Nanoparticles across Caco-2 Cell Monolayers and their Related Cytotoxicology.

    PubMed

    Chai, Gui-Hong; Xu, Yingke; Chen, Shao-Qing; Cheng, Bolin; Hu, Fu-Qiang; You, Jian; Du, Yong-Zhong; Yuan, Hong

    2016-03-09

    Solid lipid nanoparticles (SLNs) have been extensively investigated and demonstrated to be a potential nanocarriers for improving oral bioavailability of many drugs. However, the molecular mechanisms related to this discovery are not yet understood. Here, the molecular transport mechanisms of the SLNs crossing simulative intestinal epithelial cell monolayers (Caco-2 cell monolayers) were studied. The cytotoxicology results of the SLNs in Caco-2 cells demonstrated that the nanoparticles had low cytotoxicity, had no effect on the integrity of the cell membrane, did not induce oxidative stress, and could significantly reduce cell membrane fluidity. The endocytosis of the SLNs was time-dependent, and their delivery was energy-dependent. For the first time, the transport of the SLNs was directly verified to be a vesicle-mediated process. The internalization of the SLNs was mediated by macropinocytosis pathway and clathrin- and caveolae (or lipid raft)-related routes. Transferrin-related endosomes, lysosomes, endoplasmic reticulum (ER), and Golgi apparatus were confirmed to be the main destinations of the SLNs in Caco-2 cells. As for the transport of the SLNs in Caco-2 cell monolayers, the results demonstrated that the SLNs transported to the basolateral side were intact, and the transport of the nanoparticles did not destroy the structure of tight junctions. The transcytosis of the SLNs across the Caco-2 cell monolayer was demonstrated to be mediated by the same routes as that in the endocytosis study. The ER, Golgi apparatus, and microtubules were confirmed to be important for the transport of the SLNs to both the basolateral and apical membrane sides. This study provides a more thoroughly understand of SLNs transportation crossing intestinal epithelial cell monolayers and could be beneficial for the fabrication of SLNs.

  7. Modelling hillslope evolution: linear and nonlinear transport relations

    NASA Astrophysics Data System (ADS)

    Martin, Yvonne

    2000-08-01

    Many recent models of landscape evolution have used a diffusion relation to simulate hillslope transport. In this study, a linear diffusion equation for slow, quasi-continuous mass movement (e.g., creep), which is based on a large data compilation, is adopted in the hillslope model. Transport relations for rapid, episodic mass movements are based on an extensive data set covering a 40-yr period from the Queen Charlotte Islands, British Columbia. A hyperbolic tangent relation, in which transport increases nonlinearly with gradient above some threshold gradient, provided the best fit to the data. Model runs were undertaken for typical hillslope profiles found in small drainage basins in the Queen Charlotte Islands. Results, based on linear diffusivity values defined in the present study, are compared to results based on diffusivities used in earlier studies. Linear diffusivities, adopted in several earlier studies, generally did not provide adequate approximations of hillslope evolution. The nonlinear transport relation was tested and found to provide acceptable simulations of hillslope evolution. Weathering is introduced into the final set of model runs. The incorporation of weathering into the model decreases the rate of hillslope change when theoretical rates of sediment transport exceed sediment supply. The incorporation of weathering into the model is essential to ensuring that transport rates at high gradients obtained in the model reasonably replicate conditions observed in real landscapes. An outline of landscape progression is proposed based on model results. Hillslope change initially occurs at a rapid rate following events that result in oversteepened gradients (e.g., tectonic forcing, glaciation, fluvial undercutting). Steep gradients are eventually eliminated and hillslope transport is reduced significantly.

  8. Deep convective cross-tropopause transport in the tropics and evidence by A-Train satellites

    NASA Astrophysics Data System (ADS)

    Wang, P.; Su, S.,; Charvat, Z.; Setvak, M.; Cheng, K.

    2012-04-01

    Cross-tropopause transport by deep convective clouds can be an (and perhaps the most) important source of water vapor in the stratosphere. Our previous studies have verified that deep convective cross-tropopause transport does occur rather regularly in midlatitudes. This transport is demonstrated by the presence of cloud top features of above anvil cirrus plumes and jumping cirrus phenomenon that have been observed by aircraft, satellite and ground-based observations. The present paper will demonstrate that the same mechanism occurs in the tropics. Because the tropics typically have weaker wind shear at the tropopause level, previous observation did not show clear evidence of the presence of such cross-tropopause features. But the recent NSAS A-Train satellites, especially CloudSat, CALIPSO and MODIS, provide both horizontal cloud top and vertical cross-sectional views of the cloud structure and making the identification of such features much less unambiguous. In this study, we will first use cloud resolving model simulations of tropical deep connective storms to show that the gravity wave breaking mechanism and instability will cause moisture (condensed water and vapor) to be transported through the tropopause even in this weaker wind shear environment. Model animations will be shown in the conference. We will then show that the modeled storm top features match well with many recent observations by A-Train satellites. The model results and satellite observations agree not only in morphological similarity but also in the spatial extent and structure in both horizontal and vertical structure. Thus, both the model results and satellite observations demonstrate unambiguously that cross-tropopause transport of water vapor by deep convective clouds in the tropics does occur, and it should be assessed carefully for its global climatic impact.

  9. Age-related hearing loss increases cross-modal distractibility.

    PubMed

    Puschmann, Sebastian; Sandmann, Pascale; Bendixen, Alexandra; Thiel, Christiane M

    2014-10-01

    Recent electrophysiological studies have provided evidence that changes in multisensory processing in auditory cortex cannot only be observed following extensive hearing loss, but also in moderately hearing-impaired subjects. How the reduced auditory input affects audio-visual interactions is however largely unknown. Here we used a cross-modal distraction paradigm to investigate multisensory processing in elderly participants with an age-related high-frequency hearing loss as compared to young and elderly subjects with normal hearing. During the experiment, participants were simultaneously presented with independent streams of auditory and visual input and were asked to categorize either the auditory or visual information while ignoring the other modality. Unisensory sequences without any cross-modal input served as control conditions to assure that all participants were able to perform the task. While all groups performed similarly in these unisensory conditions, hearing-impaired participants showed significantly increased error rates when confronted with distracting cross-modal stimulation. This effect could be observed in both the auditory and the visual task. Supporting these findings, an additional regression analysis indicted that the degree of high-frequency hearing loss significantly modulates cross-modal visual distractibility in the auditory task. These findings provide new evidence that already a moderate sub-clinical hearing loss, a common phenomenon in the elderly population, affects the processing of audio-visual information.

  10. Transport model based on three-dimensional cross-section generation for TRIGA core analysis

    NASA Astrophysics Data System (ADS)

    Kriangchaiporn, Nateekool

    This dissertation addresses the development of a reactor core physics model based on 3-D transport methodology utilizing 3-D multigroup fuel lattice cross-section generation and core calculation for PSBR. The proposed 3-D transport calculation scheme for reactor core simulations is based on the TORT code. The methodology includes development of algorithms for 2-D and 3-D cross-section generation. The fine- and broad-group structures for the TRIGA cross-section generation problems were developed based on the CPXSD (Contributon and Point-wise Cross-Section Driven) methodology that selects effective group structure. Along with the study of cross section generation, the parametric studies for SN calculations were performed to evaluate the impact of the spatial meshing, angular, and scattering order variables and to obtain the suitable values for cross-section collapsing of the TRIGA cell problem. The TRIGA core loading 2 is used to verify and validate the selected effective group structures. Finally, the 13 group structure was selected to use for core calculations. The results agree with continuous energy for eigenvalues and normalized pin power distribution. The Monte Carlo solutions are used as the references.

  11. Intracellular Transport Routes for MHC I and Their Relevance for Antigen Cross-Presentation

    PubMed Central

    Adiko, Aimé Cézaire; Babdor, Joel; Gutiérrez-Martínez, Enric; Guermonprez, Pierre; Saveanu, Loredana

    2015-01-01

    Cross-presentation, in which exogenous antigens are presented via MHC I complexes, is involved both in the generation of anti-infectious and anti-tumoral cytotoxic CD8+ T cells and in the maintenance of immune tolerance. While cross-presentation was described almost four decades ago and while it is now established that some dendritic cell (DC) subsets are better than others in processing and cross-presenting internalized antigens, the involved molecular mechanisms remain only partially understood. Some of the least explored molecular mechanisms in cross-presentation concern the origin of cross-presenting MHC I molecules and the cellular compartments where antigenic peptide loading occurs. This review focuses on MHC I molecules and their intracellular trafficking. We discuss the source of cross-presenting MHC I in DCs as well as the role of the endocytic pathway in their recycling from the cell surface. Next, we describe the importance of the TAP peptide transporter for delivering peptides to MHC I during cross-presentation. Finally, we highlight the impact of innate immunity mechanisms on specific antigen cross-presentation mechanisms in which TLR activation modulates MHC I trafficking and TAP localization. PMID:26191062

  12. Bacterial transport of sulfate, molybdate, and related oxyanions.

    PubMed

    Aguilar-Barajas, Esther; Díaz-Pérez, César; Ramírez-Díaz, Martha I; Riveros-Rosas, Héctor; Cervantes, Carlos

    2011-08-01

    Sulfur is an essential element for microorganisms and it can be obtained from varied compounds, sulfate being the preferred source. The first step for sulfate assimilation, sulfate uptake, has been studied in several bacterial species. This article reviews the properties of different bacterial (and archaeal) transporters for sulfate, molybdate, and related oxyanions. Sulfate uptake is carried out by sulfate permeases that belong to the SulT (CysPTWA), SulP, CysP/(PiT), and CysZ families. The oxyanions molybdate, tungstate, selenate and chromate are structurally related to sulfate. Molybdate is transported mainly by the high-affinity ModABC system and tungstate by the TupABC and WtpABC systems. CysPTWA, ModABC, TupABC, and WtpABC are homologous ATP-binding cassette (ABC)-type transporters with similar organization and properties. Uptake of selenate and chromate oxyanions occurs mainly through sulfate permeases.

  13. Linking Meander Initation to Instability in the Cross-Sectional Sediment Transport Field

    NASA Astrophysics Data System (ADS)

    Eaton, B. C.

    2005-12-01

    Recent theoretical and experimental work on reach-scale channel dynamics suggests that stream channel response to changes in the discharge or sediment supply regime produce adjustments that are consistent with the optimality criteria (or extremal hypotheses) proposed by rational regime modellers. However, a general form of the optimality criteria based on the maximization of system-scale flow resistance permits multiple channel responses to the same imposed change, and is thus inadequate for predicting channel response, absent additional information. The way forward is to identify the geomorphic processes that produce various possible channel responses, and to develop an understanding of the conditions under which these processes may or may not be effective. Using a simple analytic model relating local sediment transport capacity to variance in the transverse shear stress distribution I develop a physically based conceptual model of the initiation of meandering in straight, bedload dominated streams as a result of a feedback mechanism. This corresponds to a channel response that is dominated by changes the energy slope, which appears to be dominant in channels having relatively erodible banks and transporting their bed material load at conditions near the threshold for entrainment. The feedback maximizes the cross sectional shear stress variance and, in order to achieve stability, minimizes the energy slope at repeated locations along the channel. These locations develop into pools in a fully developed meandering channel; they represent attractor states wherein sediment continuity is satisfied using the least possible energy expenditure per unit length of channel. Between two successive pools, a stream occupies a metastable, higher energy state (corresponding to a riffle) that requires greater energy expenditure per unit length of channel to transport the same volume of sediment. The model links processes at the scale of a channel width to adjustments of the

  14. Cross-shelf transport of pink shrimp larvae: Interactions of tidal currents, larval vertical migrations and internal tides

    USGS Publications Warehouse

    Criales, Maria M.; Browder, Joan A.; Mooers, C.N.K.; Robblee, M.B.; Cardenas, H.; Jackson, Thomas L.

    2007-01-01

    Transport and behavior of pink shrimp Farfantepenaeus duorarum larvae were investigated on the southwestern Florida (SWF) shelf of the Gulf of Mexico between the Dry Tortugas spawning grounds and Florida Bay nursery grounds. Stratified plankton samples and hydrographic data were collected at 2 h intervals at 3 stations located on a cross-shelf transect. At the Marquesas station, midway between Dry Tortugas and Florida Bay, internal tides were recognized by anomalously cool water, a shallow thermocline with strong density gradients, strong current shear, and a high concentration of pink shrimp larvae at the shallow thermocline. Low Richardson numbers occurred at the pycnocline depth, indicating vertical shear instability and possible turbulent transport from the lower to the upper layer where myses and postlarvae were concentrated. Analysis of vertically stratified plankton suggested that larvae perform vertical migrations and the specific behavior changes ontogenetically; protozoeae were found deeper than myses, and myses deeper than postlarvae. Relative concentrations of protozoea in the upper, middle and bottom layers were consistent with a diel vertical migration, whereas that of postlarvae and myses were consistent with the semidiurnal tides in phase with the flood tide. Postlarvae, the shallowest dwellers that migrate with a semidiurnal periodicity, experienced the largest net onshore flux and larval concentrations were highly correlated with the cross-shelf current. These results provide the first evidence of an onshore tidal transport (a type of selective tidal stream transport, STST), in decapod larvae migrating in continental shelf waters offshore, ca. 100 km from the coast and at a depth of 20 m, while approaching the coastal nursery grounds. Longer time series would be necessary to establish whether internal tides play any role in the larval onshore transport of this species and determine if the STST is the dominant onshore transport mechanism.

  15. CLC CI-/H+ Transporters Constrained by Covalent Cross-Linking

    SciTech Connect

    Nguitragool,W.; Miller, C.

    2007-01-01

    CLC Cl-/H+ exchangers are homodimers with Cl--binding and H+-coupling residues contained within each subunit. It is not known whether the transport mechanism requires conformational rearrangement between subunits or whether each subunit operates as a separate exchanger. We designed various cysteine substitution mutants on a cysteine-less background of CLC-ec1, a bacterial CLC exchanger of known structure, with the aim of covalently linking the subunits. The constructs were cross-linked in air or with exogenous oxidant, and the cross-linked proteins were reconstituted to assess their function. In addition to conventional disulfides, a cysteine-lysine cross-bridge was formed with I2 as an oxidant. The constructs, all of which contained one, two, or four cross-bridges, were functionally active and kinetically competent with respect to Cl- turnover rate, Cl-/H+ exchange stoichiometry, and H+ pumping driven by a Cl- gradient. These results imply that large quaternary rearrangements, such as those known to occur for 'common gating' in CLC channels, are not necessary for the ion transport cycle and that it is therefore likely that the transport mechanism is carried out by the subunits working individually, as with 'fast gating' of the CLC channels.

  16. Using beryllium-7 to assess cross-tropopause transport in global models

    NASA Astrophysics Data System (ADS)

    Liu, H.; Considine, D. B.; Horowitz, L. W.; Crawford, J. H.; Rodriguez, J. M.; Strahan, S. E.; Damon, M. R.; Steenrod, S. D.; Xu, X.; Kouatchou, J.; Carouge, C.; Yantosca, R. M.

    2015-09-01

    We use the Global Modeling Initiative (GMI) modeling framework to assess the utility of cosmogenic beryllium-7 (7Be), a natural aerosol tracer, for evaluating cross-tropopause transport in global models. The GMI chemical transport model (CTM) was used to simulate atmospheric 7Be distributions using four different meteorological data sets (GEOS1-STRAT DAS, GISS II' GCM, fvGCM, and GEOS4-DAS), featuring significantly different stratosphere-troposphere exchange (STE) characteristics. The simulations were compared with the upper troposphere/lower stratosphere (UT/LS) 7Be climatology constructed from ~ 25 years of aircraft and balloon data, as well as climatological records of surface concentrations and deposition fluxes. Comparison of the fraction of surface air of stratospheric origin estimated from the 7Be simulations with observationally-derived estimates indicates excessive cross-tropopause transport at middle latitudes in simulations using GEOS1-STRAT and at high latitudes using GISS II' meteorological data. These simulations also overestimate 7Be deposition fluxes at middle latitudes (GEOS1-STRAT) and at high latitudes (GISS II'), respectively. We show that excessive cross-tropopause transport of 7Be corresponds to overestimated stratospheric contribution to tropospheric ozone. Our perspectives on STE in these meteorological fields based on 7Be simulations are consistent with previous modeling studies of tropospheric ozone using the same meteorological fields. We further apply observational constraints to other global models including GFDL AM2 and GEOS-Chem (driven by GEOS3-DAS and GEOS5-DAS). We conclude that the observational constraints for 7Be and observed 7Be total deposition fluxes can be used routinely as a first-order assessment of cross-tropopause transport in global models.

  17. Using beryllium-7 to assess cross-tropopause transport in global models

    NASA Astrophysics Data System (ADS)

    Liu, Hongyu; Considine, David B.; Horowitz, Larry W.; Crawford, James H.; Rodriguez, Jose M.; Strahan, Susan E.; Damon, Megan R.; Steenrod, Stephen D.; Xu, Xiaojing; Kouatchou, Jules; Carouge, Claire; Yantosca, Robert M.

    2016-04-01

    We use the Global Modeling Initiative (GMI) modeling framework to assess the utility of cosmogenic beryllium-7 (7Be), a natural aerosol tracer, for evaluating cross-tropopause transport in global models. The GMI chemical transport model (CTM) was used to simulate atmospheric 7Be distributions using four different meteorological data sets (GEOS1-STRAT DAS, GISS II' GCM, fvGCM, and GEOS4-DAS), featuring significantly different stratosphere-troposphere exchange (STE) characteristics. The simulations were compared with the upper troposphere and/or lower stratosphere (UT/LS) 7Be climatology constructed from ˜ 25 years of aircraft and balloon data, as well as climatological records of surface concentrations and deposition fluxes. Comparison of the fraction of surface air of stratospheric origin estimated from the 7Be simulations with observationally derived estimates indicates excessive cross-tropopause transport at mid-latitudes in simulations using GEOS1-STRAT and at high latitudes using GISS II' meteorological data. These simulations also overestimate 7Be deposition fluxes at mid-latitudes (GEOS1-STRAT) and at high latitudes (GISS II'), respectively. We show that excessive cross-tropopause transport of 7Be corresponds to overestimated stratospheric contribution to tropospheric ozone. Our perspectives on STE in these meteorological fields based on 7Be simulations are consistent with previous modeling studies of tropospheric ozone using the same meteorological fields. We conclude that the observational constraints for 7Be and observed 7Be total deposition fluxes can be used routinely as a first-order assessment of cross-tropopause transport in global models.

  18. Making sense of (exceptional) causal relations. A cross-cultural and cross-linguistic study

    PubMed Central

    Le Guen, Olivier; Samland, Jana; Friedrich, Thomas; Hanus, Daniel; Brown, Penelope

    2015-01-01

    In order to make sense of the world, humans tend to see causation almost everywhere. Although most causal relations may seem straightforward, they are not always construed in the same way cross-culturally. In this study, we investigate concepts of “chance,” “coincidence,” or “randomness” that refer to assumed relations between intention, action, and outcome in situations, and we ask how people from different cultures make sense of such non-law-like connections. Based on a framework proposed by Alicke (2000), we administered a task that aims to be a neutral tool for investigating causal construals cross-culturally and cross-linguistically. Members of four different cultural groups, rural Mayan Yucatec and Tseltal speakers from Mexico and urban students from Mexico and Germany, were presented with a set of scenarios involving various types of causal and non-causal relations and were asked to explain the described events. Three links varied as to whether they were present or not in the scenarios: Intention-to-Action, Action-to-Outcome, and Intention-to-Outcome. Our results show that causality is recognized in all four cultural groups. However, how causality and especially non-law-like relations are interpreted depends on the type of links, the cultural background and the language used. In all three groups, Action-to-Outcome is the decisive link for recognizing causality. Despite the fact that the two Mayan groups share similar cultural backgrounds, they display different ideologies regarding concepts of non-law-like relations. The data suggests that the concept of “chance” is not universal, but seems to be an explanation that only some cultural groups draw on to make sense of specific situations. Of particular importance is the existence of linguistic concepts in each language that trigger ideas of causality in the responses from each cultural group. PMID:26579028

  19. Making sense of (exceptional) causal relations. A cross-cultural and cross-linguistic study.

    PubMed

    Le Guen, Olivier; Samland, Jana; Friedrich, Thomas; Hanus, Daniel; Brown, Penelope

    2015-01-01

    In order to make sense of the world, humans tend to see causation almost everywhere. Although most causal relations may seem straightforward, they are not always construed in the same way cross-culturally. In this study, we investigate concepts of "chance," "coincidence," or "randomness" that refer to assumed relations between intention, action, and outcome in situations, and we ask how people from different cultures make sense of such non-law-like connections. Based on a framework proposed by Alicke (2000), we administered a task that aims to be a neutral tool for investigating causal construals cross-culturally and cross-linguistically. Members of four different cultural groups, rural Mayan Yucatec and Tseltal speakers from Mexico and urban students from Mexico and Germany, were presented with a set of scenarios involving various types of causal and non-causal relations and were asked to explain the described events. Three links varied as to whether they were present or not in the scenarios: Intention-to-Action, Action-to-Outcome, and Intention-to-Outcome. Our results show that causality is recognized in all four cultural groups. However, how causality and especially non-law-like relations are interpreted depends on the type of links, the cultural background and the language used. In all three groups, Action-to-Outcome is the decisive link for recognizing causality. Despite the fact that the two Mayan groups share similar cultural backgrounds, they display different ideologies regarding concepts of non-law-like relations. The data suggests that the concept of "chance" is not universal, but seems to be an explanation that only some cultural groups draw on to make sense of specific situations. Of particular importance is the existence of linguistic concepts in each language that trigger ideas of causality in the responses from each cultural group.

  20. Nonlinear closure relations theory for transport processes in nonequilibrium systems.

    PubMed

    Sonnino, Giorgio

    2009-05-01

    A decade ago, a macroscopic theory for closure relations has been proposed for systems out of Onsager's region. This theory is referred to as the thermodynamic field theory (TFT). The aim of this work was to determine the nonlinear flux-force relations that respect the thermodynamic theorems for systems far from equilibrium. We propose a formulation of the TFT where one of the basic restrictions, namely, the closed-form solution for the skew-symmetric piece of the transport coefficients, has been removed. In addition, the general covariance principle is replaced by the De Donder-Prigogine thermodynamic covariance principle (TCP). The introduction of TCP requires the application of an appropriate mathematical formalism, which is referred to as the entropy-covariant formalism. By geometrical arguments, we prove the validity of the Glansdorff-Prigogine universal criterion of evolution. A new set of closure equations determining the nonlinear corrections to the linear ("Onsager") transport coefficients is also derived. The geometry of the thermodynamic space is non-Riemannian. However, it tends to be Riemannian for high values of the entropy production. In this limit, we recover the transport equations found by the old theory. Applications of our approach to transport in magnetically confined plasmas, materials submitted to temperature, and electric potential gradients or to unimolecular triangular chemical reactions can be found at references cited herein. Transport processes in tokamak plasmas are of particular interest. In this case, even in the absence of turbulence, the state of the plasma remains close to (but, it is not in) a state of local equilibrium. This prevents the transport relations from being linear.

  1. SCALING THEORY FOR CROSS-FIELD TRANSPORT OF COSMIC RAYS IN TURBULENT FIELDS

    SciTech Connect

    Hauff, T.; Jenko, F.; Shalchi, A.; Schlickeiser, R.

    2010-03-10

    The transport of charged particles (e.g., cosmic rays) in astrophysically relevant, turbulent magnetic fields (like they exist, e.g., in the solar wind) is investigated. Generic theoretical models-using concepts and insights developed recently in the context of magnetic confinement fusion research-are applied to the present problem and confirmed by means of numerical simulations. At high energies, a novel transport regime is found, in which the particles decorrelate on a gyro-orbit timescale. Explicit scaling laws for the cross-field diffusivities in various limits are derived.

  2. Effect of the cross frequency on the transport in the fusion plasmas

    NASA Astrophysics Data System (ADS)

    An, Chan-Yong; Min, Byunghoon; Kim, Chang-Bae

    2016-10-01

    The cross phase δ, i.e. the difference of the phase between the electric potential ϕ and the pressure pe, is studied in the electromagnetic resistive drift turbulence. An evolution equation for δ is obtained in the Fourier space that includes the energy-non-transporting fluxes due to E × B and magnetic nonlinearities. BOUT++ platform is used for the simulation until the steady state of the model is reached. The thermal transport Γ is found to be proportional to | pe|2 . δ and δ˙ is much smaller than the frequencies of ϕ and pe. The effect of zonal flows on δ will be presented at the conference.

  3. The twisted relation between Pnu and SWEET transporters.

    PubMed

    Jaehme, Michael; Guskov, Albert; Slotboom, Dirk Jan

    2015-04-01

    The evolutionary relation between sugar and vitamin transporters from the SWEET and Pnu families is unclear. They have similar 3D structures, but differ in the topology of their secondary structure elements, and lack significant sequence similarity. Here we analyze the structures and sequences of different members of the SWEET and Pnu transporter families and propose an evolutionary pathway by which they may have diverged from a common ancestor. A 3D domain swapping event can explain the topological differences between the families, as well as the puzzling observation that a highly conserved and essential sequence motif of the SWEET family (the PQ loop) is absent from the Pnu transporters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Positron Scattering from Molecules: An Experimental Cross Section Compilation for Positron Transport Studies and Benchmarking Theory

    NASA Astrophysics Data System (ADS)

    Brunger, M. J.; Buckman, S. J.; Ratnavelu, K.

    2017-06-01

    We present a compilation of recommended positron-molecule cross sections for a range of scattering processes including elastic scattering, vibrational excitation, discrete electronic-state excitation, positronium formation, ionization, and also for the grand total cross section. Where possible, in particular for possible application in positron transport simulations for a given molecule, we try and list data for energies in the range 0.1-1000 eV although in practice the actual energy is highly target-molecule and scattering process specific. Aside from being relevant to positron transport studies, through, for example, Monte Carlo simulations, the present compilation should also be germane for benchmarking the validity and accuracy of positron-molecule scattering calculations and, just as importantly, to allow a comparison with corresponding electron scattering results. That latter comparison can shed real light on the projectile-target interactions that underpin the scattering dynamics.

  5. Electron Cross-field Transport in a Low Power Cylindrical Hall Thruster

    SciTech Connect

    A. Smirnov; Y. Raitses; N.J. Fisch

    2004-06-24

    Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are therefore more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. Electron cross-field transport in a 2.6 cm miniaturized cylindrical Hall thruster (100 W power level) has been studied through the analysis of experimental data and Monte Carlo simulations of electron dynamics in the thruster channel. The numerical model takes into account elastic and inelastic electron collisions with atoms, electron-wall collisions, including secondary electron emission, and Bohm diffusion. We show that in order to explain the observed discharge current, the electron anomalous collision frequency {nu}{sub B} has to be on the order of the Bohm value, {nu}{sub B} {approx} {omega}{sub c}/16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant.

  6. Vorticity Dynamics of Cross-isobath Geostrophic Transport in the Stratified Steep and Concave Shelves

    NASA Astrophysics Data System (ADS)

    Jianping, G.; Hui, C. W.

    2016-02-01

    We investigated the variability and the physics of cross-isobath transport that lead to the formation of prominent upwelling centers in the steep shelf to the east of Hainan Island (EHI) and in the ambient shallow Gulf of Zhanjiang (GOZ). In situ measurements and a three-dimensional modeling showed that strengthened upslope transport of cold deep waters occurred in these two shelves, which are characterized by steep slope and concaving isobaths, respectively. The major driving force for these shoreward cross-isobath transports were not from the bottom frictional dynamics, but from the along-isobath pressure gradient force (PGF) as a result of the flow response to the variable shelf topography. The physical origins of the PGF of these prominent upwelling centers, however, were dynamically different. We found that the sources of the PGF were the Modified Joint Effect Baroclinicity and Relief (MJEBAR) due to importance of baroclinicity in the steep EHI and the net water-column stress curl in the concaving GOZ. The along-shelf geostrophic current that maintains the flow-topography interaction for the formation of the PGF was determined by the competing slope and baroclinic effects in EHI and by the cross-isobath changing bottom pressure in GOZ. Based on depth-integrated vorticity dynamics for a stratified and free-surface sea, this study illustrates the contrasting forcing functions of the three-dimensional circulation over the steep and shallow concaving shelves.

  7. A close look at axonal transport: Cargos slow down when crossing stationary organelles.

    PubMed

    Che, Daphne L; Chowdary, Praveen D; Cui, Bianxiao

    2016-01-01

    The bidirectional transport of cargos along the thin axon is fundamental for the structure, function and survival of neurons. Defective axonal transport has been linked to the mechanism of neurodegenerative diseases. In this paper, we study the effect of the local axonal environment to cargo transport behavior in neurons. Using dual-color fluorescence imaging in microfluidic neuronal devices, we quantify the transport dynamics of cargos when crossing stationary organelles such as non-moving endosomes and stationary mitochondria in the axon. We show that the axonal cargos tend to slow down, or pause transiently within the vicinity of stationary organelles. The slow-down effect is observed in both retrograde and anterograde transport directions of three different cargos (TrkA, lysosomes and TrkB). Our results agree with the hypothesis that bulky axonal structures can pose as steric hindrance for axonal transport. However, the results do not rule out the possibility that cellular mechanisms causing stationary organelles are also responsible for the delay in moving cargos at the same locations.

  8. Cross-Saharan transport of water vapor via recycled cold pool outflows from moist convection

    NASA Astrophysics Data System (ADS)

    Trzeciak, Tomasz M.; Garcia-Carreras, Luis; Marsham, John H.

    2017-02-01

    Very sparse data have previously limited observational studies of meteorological processes in the Sahara. We present an observed case of convectively driven water vapor transport crossing the Sahara over 2.5 days in June 2012, from the Sahel in the south to the Atlas in the north. A daily cycle is observed, with deep convection in the evening generating moist cold pools that fed the next day's convection; the convection then generated new cold pools, providing a vertical recycling of moisture. Trajectories driven by analyses were able to capture the direction of the transport but not its full extent, particularly at night when cold pools are most active, and analyses missed much of the water content of cold pools. The results highlight the importance of cold pools for moisture transport, dust and clouds, and demonstrate the need to include these processes in models in order to improve the representation of Saharan atmosphere.

  9. Vitamin C crosses the blood-brain barrier in the oxidized form through the glucose transporters.

    PubMed Central

    Agus, D B; Gambhir, S S; Pardridge, W M; Spielholz, C; Baselga, J; Vera, J C; Golde, D W

    1997-01-01

    Vitamin C concentrations in the brain exceed those in blood by 10-fold. In both tissues, the vitamin is present primarily in the reduced form, ascorbic acid. We identified the chemical form of vitamin C that readily crosses the blood-brain barrier, and the mechanism of this process. Ascorbic acid was not able to cross the blood-brain barrier in our studies. In contrast, the oxidized form of vitamin C, dehydroascorbic acid (oxidized ascorbic acid), readily entered the brain and was retained in the brain tissue in the form of ascorbic acid. Transport of dehydroascorbic acid into the brain was inhibited by d-glucose, but not by l-glucose. The facilitative glucose transporter, GLUT1, is expressed on endothelial cells at the blood-brain barrier, and is responsible for glucose entry into the brain. This study provides evidence showing that GLUT1 also transports dehydroascorbic acid into the brain. The findings define the transport of dehydroascorbic acid by GLUT1 as a mechanism by which the brain acquires vitamin C, and point to the oxidation of ascorbic acid as a potentially important regulatory step in accumulation of the vitamin by the brain. These results have implications for increasing antioxidant potential in the central nervous system. PMID:9389750

  10. Detection of barriers to cross-jet Lagrangian transport and its destruction in a meandering flow

    NASA Astrophysics Data System (ADS)

    Budyansky, M. V.; Uleysky, M. Yu.; Prants, S. V.

    2009-05-01

    Cross-jet transport of passive scalars in a kinematic model of the meandering laminar two-dimensional incompressible flow which is known to produce chaotic mixing is studied. We develop a method for detecting barriers to cross-jet transport in the phase space which is a physical space for our model. Using tools from the theory of nontwist maps, we construct a central invariant curve and compute its characteristics that may serve as good indicators of the existence of a central transport barrier, its strength, and topology. Computing fractal dimension, length, and winding number of that curve in the parameter space, we study in detail the change in its geometry and its destruction that is caused by local bifurcations and a global bifurcation known as reconnection of separatrices of resonances. Scenarios of reconnection are different for odd and even resonances. The central invariant curves with rational and irrational (noble) values of winding numbers are arranged into hierarchical series which are described in terms of continued fractions. Destruction of central transport barrier is illustrated for two ways in the parameter space: when moving along resonant bifurcation curves with rational values of the winding number and along curves with noble (irrational) values.

  11. Elastic and transport cross sections for inert gases in a hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Krstic, Predrag

    2005-05-01

    Accurate elastic differential and integral scattering and transport cross sections have been computed using a fully quantum-mechanical approach for hydrogen ions (H^+, D^+ and T^+) colliding with Neon, Krypton and Xenon, in the center of mass energy range 0.1 to 200 eV. The momentum transfer and viscosity cross sections have been extended to higher keV collision energies using a classical, three-body scattering method. The results were compared with previously calculated values for Argon and Helium, as well as with simple analytical models. The cross sections, tabulated and available through the world wide web (www-cfadc.phy.ornl.gov) are of significance in fusion plasma modeling, gaseous electronics and other plasma applications.

  12. The role of Ekman flow and planetary waves in the oceanic cross-equatorial heat transport

    NASA Technical Reports Server (NTRS)

    Schopf, P. S.

    1980-01-01

    A numerical model is used to mechanistically simulate the oceans' seasonal cross-equatorial heat transport. The basic process of Ekman pumping and drift is able to account for a large amount of the cross-equatorial flux. Increased easterly wind stress in the winter hemisphere causes Ekman surface drift poleward, while decreased easterly stress allows a reduction in the poleward drift in the summer hemisphere. The addition of planetary and gravity waves to this model does not alter the net cross-equatorial flow, although the planetary waves are clearly seen. On comparison with Oort and Vonder Haar (1976), this adiabatic advective redistribution of heat is seen to be plausible up to 10-20 deg N, beyond which other dynamics and thermodynamics are indicated.

  13. Generation of discrete scattering cross sections and demonstration of Monte Carlo charged particle transport in the Milagro IMC code package

    SciTech Connect

    Walsh, J. A.; Palmer, T. S.; Urbatsch, T. J.

    2013-07-01

    A new method for generating discrete scattering cross sections to be used in charged particle transport calculations is investigated. The method of data generation is presented and compared to current methods for obtaining discrete cross sections. The new, more generalized approach allows greater flexibility in choosing a cross section model from which to derive discrete values. Cross section data generated with the new method is verified through a comparison with discrete data obtained with an existing method. Additionally, a charged particle transport capability is demonstrated in the time-dependent Implicit Monte Carlo radiative transfer code package, Milagro. The implementation of this capability is verified using test problems with analytic solutions as well as a comparison of electron dose-depth profiles calculated with Milagro and an already-established electron transport code. An initial investigation of a preliminary integration of the discrete cross section generation method with the new charged particle transport capability in Milagro is also presented. (authors)

  14. Hysteresis and fast timescales in transport relations of toroidal plasmas

    NASA Astrophysics Data System (ADS)

    Itoh, K.; Itoh, S.-I.; Ida, K.; Inagaki, S.; Kamada, Y.; Kamiya, K.; Dong, J. Q.; Hidalgo, C.; Evans, T.; Ko, W. H.; Park, H.; Tokuzawa, T.; Kubo, S.; Kobayashi, T.; Kosuga, Y.; Sasaki, M.; Yun, G. S.; Song, S. D.; Kasuya, N.; Nagashima, Y.; Moon, C.; Yoshinuma, M.; Makino, R.; Tsujimura, T.; Tsuchiya, H.; Stroth, U.

    2017-10-01

    This article assesses current understanding of hysteresis in transport relations, and its impact on the field. The rapid changes of fluxes compared to slow changes of plasma parameters are overviewed for both core and edge plasmas. The modulation ECH experiment is explained, in which the heating power cycles on-and-off periodically, revealing hysteresis and fast changes in the gradient-flux relation. The key finding is that hystereses were observed simultaneously in both the the gradient-flux and gradient-fluctuation relations. Hysteresis with rapid timescale exists in the channels of energy, electron and impurity densities, and plausibly in momentum. Advanced methods of data analysis are explained. Transport hysteresis can be studied by observing the higher harmonics of temperature perturbation δ Tm in heating modulation experiments. The hysteresis introduces the term δ Tm , which depends on the harmonic number m in an algebraic manner (not exponential decay). Next, the causes of hysteresis and its fast timescale are discussed. The nonlocal-in-space coupling works here, but does not suffice. One mechanism for ‘the heating heats turbulence’ is that the external source S in phase space for heating has its fluctuation in turbulent plasma. This coupling can induce the direct input of heating power into fluctuations. The height of the jump in transport hysteresis is smaller for heavier hydrogen isotopes, and could be one of the origins of isotope effects on confinement. Finally, the impacts of transport hysteresis on the control system are assessed. Control systems must be designed so as to protect the system from sudden plasma loss.

  15. Magneto transport in crossed electric and magnetic fields in compensated bulk GaN

    NASA Astrophysics Data System (ADS)

    Syngayivska, G. I.; Korotyeyev, V. V.; Kochelap, V. A.; Varani, L.

    2016-09-01

    Low-temperature high-field electron transport is studied for compensated bulk GaN subjected to crossed electric and magnetic fields. The electron kinetics, distribution function, and field dependencies of the magneto transport characteristics are analyzed by using the Monte-Carlo method. At zero magnetic field, for an ionized impurity concentration of 1016 cm-3 and an electron concentration of 1015 cm-3, it is shown that dissipative streaming transport with a strong anisotropic electron distribution in the momentum space is realized at electric fields in the range 3 -10 kV/cm and for a lattice temperature of 30 K. The magnetic field destroys the dissipative streaming transport. Indeed, for a magnetic field greater than 4 T, the electrons are predominantly confined in a region of the momentum space where their energy is smaller than the optical phonon energy and the strong inelastic scattering by optical phonons is practically eliminated. A quasi-ballistic electron transport occurs in the form of a vortex-like motion in the momentum space. The axis of rotation of this vortex coincides with the average electron momentum. A general analysis of the distribution function suitable for any configuration of the Hall circuit is presented. The main magneto transport characteristics (dissipative current, Hall current, and Hall electric field) are studied for the short and open Hall circuits. We show that the magneto transport measurements can provide valuable information on the main features of the electron distribution function and electron dynamics in GaN. Finally, we suggest that the strong dependency of the dissipative current on the parameters of the Hall circuit can be used for current modulation and current switching.

  16. Cross-linking of dimeric CitS and GltS transport proteins.

    PubMed

    Krupnik, Tomasz; Dobrowolski, Adam; Lolkema, Juke S

    2011-08-01

    CitS of Klebsiella pneumoniae and GltS of Escherichia coli are Na+-dependent secondary transporters from different families that are believed to share the same fold and quaternary structure. A 10 kDa protein tag (Biotin Acceptor Domain [BAD]) was fused to the N-terminus of both proteins (CitS-BAD1 and GltS-BAD1, respectively) and inserted in the central cytoplasmic loop that connects the two halves of the proteins (CitS-BAD260 and GltS-BAD206). Both CitS constructs and GltS-BAD206 were produced and shown to be active transporters, but GltS-BAD1 could not be detected in the membrane. Distance relationships in the complexes were studied by cross-linking studies. Both CitS constructs were shown to be in the dimeric state after purification in detergent by cross-linking with glutaraldehyde. The concentration of glutaraldehyde resulting in 50% cross-linking was significantly higher for CitS-BAD1 than for CitS and CitS-BAD260. Remarkably, GltS and GltS-BAD260 were not cross-linked by glutaraldehyde because of the lack of productive reactive sites. Cross-linking of GltS was observed when the N-terminal 46 residues of CitS with or without BAD at the N-terminus were added to the N-terminus of GltS. The stretch of 46 residues contains the first transmembrane segment of CitS that is missing in the GltS structure. The data support an orientation of the monomers in the dimer with the N-termini close to the dimer interface and the central cytoplasmic loops far away at the ends of the long axis of the dimer structure in a view perpendicular to the membrane.

  17. Methodological problems in cross-cultural studies of linguistic relativity.

    PubMed

    Takano, Y

    1989-03-01

    Bloom (1981) tested a weak version of the linguistic relativity hypothesis (i.e., "Language affects thinking though it does not determine thinking") in a series of cross-cultural experiments. According to Bloom, Chinese lacks two linguistic devices that are present in English and supposed to be critical in performing theoretical thinking. It was found that the Chinese subjects were outperformed by American counterparts in all the tests designed to assess the ability of theoretical thinking. The results were taken as evidence for the weak version of the linguistic relativity hypothesis. A methodological consideration has revealed, however, that all of his experiments except one are uninterpretable because of the lack of necessary control conditions. In addition, three experiments in the present study have demonstrated that the findings in Bloom's sole interpretable experiment were artifacts due to a methodological flaw. Further theoretical considerations reveal the inadequacy of Bloom's basic methodology and the limitation in the effects of linguistic relativity that may be possible at least theoretically.

  18. Thermally cross-linkable hole transport polymers for solution-based organic light-emitting diodes.

    PubMed

    Cha, Seung Ji; Cho, Se-Na; Lee, Woo-Hyung; Chung, Ha-Seul; Kang, In-Nam; Suh, Min Chul

    2014-04-01

    Two thermally cross-linkable hole transport polymers that contain phenoxazine and triphenylamine moieties, X-P1 and X-P2, are developed for use in solution-processed multi-stack organic light-emitting diodes (OLEDs). Both X-P1 and X-P2 exhibit satisfactory cross-linking and optoelectronic properties. The highest occupied molecular orbital (HOMO) levels of X-P1 and X-P2 are -5.24 and -5.16 eV, respectively. Solution-processed super yellow polymer devices (ITO/X-P1 or X-P2/PDY-132/LiF/Al) with X-P1 or X-P2 hole transport layers of various thicknesses are fabricated with the aim of optimizing the device characteristics. The fabricated multi-stack yellow devices containing the newly synthesized hole transport polymers exhibit satisfactory currents and power efficiencies. The optimized X-P2 device exhibits a device efficiency that is dramatically improved by more than 66% over that of a reference device without an HTL.

  19. Monte Carlo Simulation of the Transport of Electrons in Semi-Infinite Solids:. the Effect of the First Transport Cross-Section

    NASA Astrophysics Data System (ADS)

    Bentabet, A.

    The purpose of this work is to show the hidden effect of the first transport cross-section in the study of the beam electrons transport impinging in solid targets by using the Monte Carlo method. For this, our study is based on our model of differential elastic cross-section given [A. Bentabet, Z. Chaoui, A. Aydin and A. Azbouche, Vacuum 85 (2010) 156] by leaving only one free parameter adjusted, on one hand, to the elastic total cross-section and to transport cross-section, on the other hand. We think that this work is useful for those who develop semi-empirical or analytical models of elastic cross-sections. The present work deals with the total elastic cross-section, the first transport cross-section, the diffusion polar angle and the backscattering coefficient, from low energy electrons, normally incident, impinging on Al, Si, Ag and Au solid targets, where the results are compared to those of the literature and discussed.

  20. A CUMULATIVE MIGRATION METHOD FOR COMPUTING RIGOROUS TRANSPORT CROSS SECTIONS AND DIFFUSION COEFFICIENTS FOR LWR LATTICES WITH MONTE CARLO

    SciTech Connect

    Zhaoyuan Liu; Kord Smith; Benoit Forget; Javier Ortensi

    2016-05-01

    A new method for computing homogenized assembly neutron transport cross sections and dif- fusion coefficients that is both rigorous and computationally efficient is proposed in this paper. In the limit of a homogeneous hydrogen slab, the new method is equivalent to the long-used, and only-recently-published CASMO transport method. The rigorous method is used to demonstrate the sources of inaccuracy in the commonly applied “out-scatter” transport correction. It is also demonstrated that the newly developed method is directly applicable to lattice calculations per- formed by Monte Carlo and is capable of computing rigorous homogenized transport cross sections for arbitrarily heterogeneous lattices. Comparisons of several common transport cross section ap- proximations are presented for a simple problem of infinite medium hydrogen. The new method has also been applied in computing 2-group diffusion data for an actual PWR lattice from BEAVRS benchmark.

  1. Childhood emotional and sexual maltreatment moderate the relation of the serotonin transporter gene to stress generation.

    PubMed

    Harkness, Kate L; Bagby, R Michael; Stewart, Jeremy G; Larocque, Cherie L; Mazurka, Raegan; Strauss, John S; Ravindran, Arun; Rector, Neil A; Wynne-Edwards, Katherine E; Kennedy, James L

    2015-05-01

    Emerging evidence suggests that the tendency to generate stressful life events may be, at least in part, genetically determined. However, the role of the early environment in shaping responses to later stressors is crucial to fully specifying biogenetic models of stress generation. The current study examined the moderating role of childhood emotional, physical, and sexual maltreatment on the relation of the serotonin-transporter-linked promoter region (5-HTTLPR) polymorphism of the serotonin transporter gene to proximal independent, dependent, and dependent-interpersonal life events. This question was tested in a cross-sectional community sample of 297 adolescents and young adults. Childhood maltreatment history and proximal life events were assessed with state-of-the-art interviews that provide independent and standardized ratings of the environmental context. Consistent with the stress generation hypothesis, individuals with the risk s-allele of the serotonin transporter gene reported significantly higher rates of dependent and dependent-interpersonal life events than those homozygous for the l-allele, but only in the context of a history of maternal emotional maltreatment or sexual maltreatment. Neither serotonin transporter gene polymorphisms or childhood maltreatment, or their interaction, were associated with reports of independent life events. The current results demonstrate the importance of considering specificity in the early environmental context when examining the relation of genetic factors to the generation of proximal stress. (c) 2015 APA, all rights reserved).

  2. Observational Constraints on Atmospheric and Oceanic Cross-Equatorial Heat Transports: Revisiting the Precipitation Asymmetry Problem in Climate Models

    NASA Astrophysics Data System (ADS)

    Loeb, N. G.; Wang, H.; Cheng, A.; Kato, S.; Fasullo, J.; Xu, K. M.; Allan, R. P.

    2015-12-01

    Recent studies have shown strong linkages between hemispheric asymmetries in atmospheric and oceanic energy budgets, tropical precipitation and the mean position of the Intertropical Convergence Zone (ITCZ). The energetics framework has been used to explain why the mean position of the ITCZ is in the Northern Hemisphere and to study large-scale circulation and precipitation responses to changes in the hemispheric distribution of heating. Here, we expand upon these earlier studies by also considering estimates of hemispheric asymmetry in surface and atmospheric radiation budget derived from satellite observations, which enables a decomposition of cross-equatorial heat transport in terms of radiative and non-radiative (i.e., combined latent and sensible heat) components. Satellite observations of top-of-atmosphere (TOA) and surface radiation budget from the Clouds and the Earth's Radiation Budget (CERES) are combined with mass corrected vertically integrated atmospheric energy divergence from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Observed radiative and combined sensible and latent heat contributions to atmospheric and oceanic cross-equatorial heat transports are compared with simulations from 30 models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5). Results show that most CMIP5 models that overestimate tropical precipitation in the SH have too much net downward surface radiation and combined latent and sensible heat flux in the SH relative to the NH. In addition, many of the models also underestimate atmospheric radiative cooling in the SH compared to the NH. Consequently, the models have excessive heating of the SH atmosphere and anomalous SH to NH cross-equatorial heat transport. The anomalous northward heat transport occurs via the upper branch of the northern Hadley Cell, while anomalous NH to SH moisture transport occurs in the lower branch of the northern

  3. Correcting evaluation bias of relational classifiers with network cross validation

    SciTech Connect

    Neville, Jennifer; Gallagher, Brian; Eliassi-Rad, Tina; Wang, Tao

    2011-01-04

    Recently, a number of modeling techniques have been developed for data mining and machine learning in relational and network domains where the instances are not independent and identically distributed (i.i.d.). These methods specifically exploit the statistical dependencies among instances in order to improve classification accuracy. However, there has been little focus on how these same dependencies affect our ability to draw accurate conclusions about the performance of the models. More specifically, the complex link structure and attribute dependencies in relational data violate the assumptions of many conventional statistical tests and make it difficult to use these tests to assess the models in an unbiased manner. In this work, we examine the task of within-network classification and the question of whether two algorithms will learn models that will result in significantly different levels of performance. We show that the commonly used form of evaluation (paired t-test on overlapping network samples) can result in an unacceptable level of Type I error. Furthermore, we show that Type I error increases as (1) the correlation among instances increases and (2) the size of the evaluation set increases (i.e., the proportion of labeled nodes in the network decreases). Lastly, we propose a method for network cross-validation that combined with paired t-tests produces more acceptable levels of Type I error while still providing reasonable levels of statistical power (i.e., 1–Type II error).

  4. Correcting evaluation bias of relational classifiers with network cross validation

    DOE PAGES

    Neville, Jennifer; Gallagher, Brian; Eliassi-Rad, Tina; ...

    2011-01-04

    Recently, a number of modeling techniques have been developed for data mining and machine learning in relational and network domains where the instances are not independent and identically distributed (i.i.d.). These methods specifically exploit the statistical dependencies among instances in order to improve classification accuracy. However, there has been little focus on how these same dependencies affect our ability to draw accurate conclusions about the performance of the models. More specifically, the complex link structure and attribute dependencies in relational data violate the assumptions of many conventional statistical tests and make it difficult to use these tests to assess themore » models in an unbiased manner. In this work, we examine the task of within-network classification and the question of whether two algorithms will learn models that will result in significantly different levels of performance. We show that the commonly used form of evaluation (paired t-test on overlapping network samples) can result in an unacceptable level of Type I error. Furthermore, we show that Type I error increases as (1) the correlation among instances increases and (2) the size of the evaluation set increases (i.e., the proportion of labeled nodes in the network decreases). Lastly, we propose a method for network cross-validation that combined with paired t-tests produces more acceptable levels of Type I error while still providing reasonable levels of statistical power (i.e., 1–Type II error).« less

  5. Electron Cross-field Transport in a Miniaturized Cylindrical Hall Thruster

    SciTech Connect

    Smirnov Artem, Raitses Yevgeny, Fisch Nathaniel J

    2005-10-14

    Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. The present paper gives a review of the experimental and numerical investigations of electron crossfield transport in the 2.6 cm miniaturized cylindrical Hall thruster (100 W power level). We show that, in order to explain the discharge current observed for the typical operating conditions, the electron anomalous collision frequency {nu}{sub b} has to be on the order of the Bohm value, {nu}{sub B} {approx} {omega}{sub c}/16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant. The optimal regimes of thruster operation at low background pressure (below 10{sup -5} Torr) in the vacuum tank appear to be different from those at higher pressure ({approx} 10{sup -4} Torr).

  6. N(+)-N and O(+)-O interaction energies, dipole transition moments, and transport cross sections

    NASA Technical Reports Server (NTRS)

    Partridge, H.; Stallcop, J. R.

    1986-01-01

    Complete sets of ion-atom interaction energies have been computed for nitrogen and oxygen with accurate large scale structure calculations. The computed energies agree well with the accurate potential curves available from spectroscopic measurement. The state functions from the nitrogen calculations have been applied to determine the transition moment for all allowed dipole transitions. These results can be combined to compute a detailed radiation spectrum such as that required to define the highly nonequilibrium environment of aeroassisted orbital transfer vehicle (AOTV). The long-range interaction energies have been used to determine the ion-atom resonance charge exchange cross sections that are important for transport processes such as diffusion. A calculation to determine reliable transport properties for energies that include the AOTV temperature range from these computed properties is described.

  7. Cross-shore transport of nearshore sediment by river plume frontal pumping

    NASA Astrophysics Data System (ADS)

    Horner-Devine, Alexander R.; Pietrzak, Julie D.; Souza, Alejandro J.; McKeon, Margaret A.; Meirelles, Saulo; Henriquez, Martijn; Flores, Raúl P.; Rijnsburger, Sabine

    2017-06-01

    We present a new mechanism for cross-shore transport of fine sediment from the nearshore to the inner shelf resulting from the onshore propagation of river plume fronts. Onshore frontal propagation is observed in moorings and radar images, which show that fronts penetrate onshore through the nearshore and surf zone, almost to the waterline. During frontal passage a two-layer counterrotating velocity field characteristic of tidal straining is immediately set up, generating a net offshore flow beneath the plume. The seaward flow at depth carries with it high suspended sediment concentrations, which appear to have been generated by wave resuspension in the nearshore region. These observations describe a mechanism by which vertical density stratification can drive exchange of material between the nearshore region and the inner shelf. To our knowledge these are the first observations of this frontal pumping mechanism, which is expected to play an important role in sediment transport near river mouths.

  8. Volumetric Deformation of Live Cells Induced by Pressure-Activated Cross-Membrane Ion Transport

    NASA Astrophysics Data System (ADS)

    Hui, T. H.; Zhou, Z. L.; Qian, J.; Lin, Y.; Ngan, A. H. W.; Gao, H.

    2014-09-01

    In this work, we developed a method that allows precise control over changes in the size of a cell via hydrostatic pressure changes in the medium. Specifically, we show that a sudden increase, or reduction, in the surrounding pressure, in the physiologically relevant range, triggers cross-membrane fluxes of sodium and potassium ions in leukemia cell lines K562 and HL60, resulting in reversible volumetric deformation with a characteristic time of around 30 min. Interestingly, healthy leukocytes do not respond to pressure shocks, suggesting that the cancer cells may have evolved the ability to adapt to pressure changes in their microenvironment. A model is also proposed to explain the observed cell deformation, which highlights how the apparent viscoelastic response of cells is governed by the microscopic cross-membrane transport.

  9. Anomalous cross-B field transport and spokes in HiPIMS plasma

    NASA Astrophysics Data System (ADS)

    Hecimovic, A.

    2016-05-01

    Localized light emission patterns observed during on time of a high power impulse magnetron sputtering (HiPIMS) discharge on a planar magnetron, known as spokes or ionization zones, have been identified as a potential source of anomalous cross-B field diffusion. In this paper experimental evidence is presented that anomalous diffusion is triggered by the appearance of spokes. The Hall parameter {ω\\text{ce}}{τ\\text{c}} , product of the electron cyclotron frequency and the classical collision time, reduces from Bohm diffusion values (∼ 16 and higher) down to the value of 3 as spokes appear, indicating anomalous cross-B field transport. A combination of intensified charge coupled device imaging and electric probe measurements reveals that the ions from the spokes are instantaneously diffusing away from the target. The ion diffusion coefficients calculated from a sideways image of the spoke are six times higher than Bohm diffusion coefficients, which is consistent with the reduction of the Hall parameter.

  10. Cross-plane electrical and thermal transport in oxide metal/semiconductor superlattices

    NASA Astrophysics Data System (ADS)

    Jha, Pankaj

    Perovskite oxides display a rich variety of electronic properties as metals, ferroelectrics, ferromagnetics, multiferroics, and thermoelectrics. Cross-plane electron filtering transport in metal/semiconductor superlattices provides a potential approach to increase the thermoelectric figure of merit (ZT). La0.67Sr0.33MnO3 (LSMO) and LaMnO3 (LMO) thin-film depositions were optimized using pulsed laser deposition (PLD) to achieve low resistivity constituent materials for LSMO/LMO superlattice heterostructures on (100)-strontium titanate (STO) substrates. X-ray diffraction and high-resolution reciprocal space mapping (RSM) indicate that the superlattices are epitaxial and pseudomorphic. Cross-plane devices were fabricated by etching cylindrical pillar structures in superlattices using inductively-coupled-plasma reactive-ion etching. The cross-plane electrical conductivity data for LSMO/LMO superlattices reveal an effective barrier height of 220 meV. The cross-plane LSMO/LMO superlattices showed a giant Seebeck coefficient of 2560 microV/K at 300K that increases to 16640 microV/K at 360K. The large Seebeck coefficient may arise due to hot electron and spin filtering as LSMO/LMO superlattice constituent materials exhibit spintronic properties where charges and spin current are intertwined and can generate a spin-Seebeck effect. The room temperature thermal conductivity achieved in low resistivity superlattices was 0.92 W/mK, which indicates that cross-plane phonon scattering at interfaces reduces the lattice contribution to the thermal conductivity. The giant contribution of spin-Seebeck, the large temperature dependence of the cross-plane power factor, and the low thermal conductivity in low resistance LSMO/LMO superlattices may offer opportunities to realize spin-magnetic thermoelectric devices, and suggests a direction for further investigations of the potential of LSMO/LMO oxide superlattices for thermoelectric devices.

  11. Off-Highway Transportation-Related Fuel Use

    SciTech Connect

    Davis, S.C.

    2004-05-08

    The transportation sector includes many subcategories--for example, on-highway, off-highway, and non-highway. Use of fuel for off-highway purposes is not well documented, nor is the number of off-highway vehicles. The number of and fuel usage for on-highway and aviation, marine, and rail categories are much better documented than for off-highway land-based use. Several sources document off-highway fuel use under specific conditions--such as use by application (e.g., recreation) or by fuel type (e.g., gasoline). There is, however, no single source that documents the total fuel used off-highway and the number of vehicles that use the fuel. This report estimates the fuel usage and number of vehicles/equipment for the off-highway category. No new data have been collected nor new models developed to estimate the off-highway data--this study is limited in scope to using data that already exist. In this report, unless they are being quoted from a source that uses different terminology, the terms are used as listed below. (1) ''On-highway/on-road'' includes land-based transport used on the highway system or other paved roadways. (2) ''Off-highway/off-road'' includes land-based transport not using the highway system or other paved roadways. (3) ''Non-highway/non-road'' includes other modes not traveling on highways such as aviation, marine, and rail. It should be noted that the term ''transportation'' as used in this study is not typical. Generally, ''transportation'' is understood to mean the movement of people or goods from one point to another. Some of the off-highway equipment included in this study doesn't transport either people or goods, but it has utility in movement (e.g., a forklift or a lawn mower). Along these lines, a chain saw also has utility in movement, but it cannot transport itself (i.e., it must be carried) because it does not have wheels. Therefore, to estimate the transportation-related fuel used off-highway, transportation equipment is defined to

  12. Effective Potential Energies and Transport Cross Sections for Interactions of Hydrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, James R. (Technical Monitor)

    2000-01-01

    The interaction energies for N2-He and N2-H2 are calculated by accurate ab initio methods. The virial coefficient and differential scattering cross section for N2-H2 are calculated; the theoretical results are compared with experimental data. The transport collision integrals for N2-H2 and N2-N2 interactions are calculated and tabulated; the results yield transport coefficients that compare well with measured data. Transport coefficients are found to be determined accurately from the interaction energies for a specific configuration of the molecule formed from the interaction partners. Comparisons with results of measurement and accurate calculations demonstrate that the transport properties of complex molecular interactions can be determined rapidly and fairly accurately from the interaction energies of simpler system using combination rules for the short-range parameters of effective interaction energies and the coefficients for the long-range forces. The coefficients for a two-parameter temperature expansion of diffusion and viscosity are tabulated for a realistic universal potential energy that is based primarily on the results of very accurate calculations of the He-He interaction energy.

  13. Nonequilibrium cross-plane energy transport in aluminum-silicon-aluminum wafer

    NASA Astrophysics Data System (ADS)

    Bin Mansoor, Saad; Yilbas, Bekir Sami

    2015-05-01

    Transient phonon transport across cross-planes of aluminum-silicon-aluminum combined films is investigated and the Boltzmann transport equation is incorporated to formulate the energy transport in the combined films. Since electrons and phonons thermally separate in the thin aluminum film during heating, the Boltzmann equation is used separately in the electron and lattice subsystems to account for the energy transport in the aluminum film. Electron-phonon coupling is incorporated for the energy exchange between electron and lattice subsystems in the film. Thermal boundary resistance (TBR) is introduced at the interfaces of the silicon-aluminum films. In order to examine the ballistic contribution of phonons on the phonon intensity distribution in the silicon film, frequency-dependent solution of the Boltzmann equation is used in the silicon film and the film thickness is varied to investigate the size effect on the thermal conductivity in the film. It is found that equivalent equilibrium temperature of phonons remains high at silicon-aluminum interface because of the ballistic contribution of the phonons. Equivalent equilibrium temperature for the electron subsystem becomes higher than that corresponding to phonon temperature at the aluminum-silicon interface.

  14. Effective Potential Energies and Transport Cross Sections for Interactions of Hydrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, James R. (Technical Monitor)

    2000-01-01

    The interaction energies for N2-He and N2-H2 are calculated by accurate ab initio methods. The virial coefficient and differential scattering cross section for N2-H2 are calculated; the theoretical results are compared with experimental data. The transport collision integrals for N2-H2 and N2-N2 interactions are calculated and tabulated; the results yield transport coefficients that compare well with measured data. Transport coefficients are found to be determined accurately from the interaction energies for a specific configuration of the molecule formed from the interaction partners. Comparisons with results of measurement and accurate calculations demonstrate that the transport properties of complex molecular interactions can be determined rapidly and fairly accurately from the interaction energies of simpler system using combination rules for the short-range parameters of effective interaction energies and the coefficients for the long-range forces. The coefficients for a two-parameter temperature expansion of diffusion and viscosity are tabulated for a realistic universal potential energy that is based primarily on the results of very accurate calculations of the He-He interaction energy.

  15. Turbulent jets and eddies in the california current and inferred cross-shore transports.

    PubMed

    Mooers, C N; Robinson, A R

    1984-01-06

    The instantaneous California Current is seen to consist of intense meandering current filaments (jets) intermingled with synoptic-mesoscale eddies. These quasi-geostrophic jets entrain cold, upwelled coastal waters and rapidly advect them far offshore; this behavior accounts for the elongated, cool surface features that are seen extending across the California Current region in satellite infrared imagery. The associated advective mechanism should provide significant cross-shore transports of heat, nutrients, biota, and pollutants. The dynamics of the current system should be crucially influenced by its highly variable structure.

  16. Influence of oblique magnetic field on electron cross-field transport in a Hall effect thruster

    SciTech Connect

    Miedzik, Jan; Daniłko, Dariusz; Barral, Serge

    2015-04-15

    The effects of the inclination of the magnetic field with respect to the channel walls in a Hall effect thruster are numerically studied with the use of a one-dimensional quasi-neutral Particle-In-Cell model with guiding center approximation of electron motion along magnetic lines. Parametric studies suggest that the incidence angle strongly influences electron transport across the magnetic field. In ion-focusing magnetic topologies, electrons collide predominantly on the side of the magnetic flux tube closer to the anode, thus increasing the electron cross-field drift. The opposite effect is observed in ion-defocussing topology.

  17. Cross-layer restoration with software defined networking based on IP over optical transport networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Cheng, Lei; Deng, Junni; Zhao, Yongli; Zhang, Jie; Lee, Young

    2015-10-01

    The IP over optical transport network is a very promising networking architecture applied to the interconnection of geographically distributed data centers due to the performance guarantee of low delay, huge bandwidth and high reliability at a low cost. It can enable efficient resource utilization and support heterogeneous bandwidth demands in highly-available, cost-effective and energy-effective manner. In case of cross-layer link failure, to ensure a high-level quality of service (QoS) for user request after the failure becomes a research focus. In this paper, we propose a novel cross-layer restoration scheme for data center services with software defined networking based on IP over optical network. The cross-layer restoration scheme can enable joint optimization of IP network and optical network resources, and enhance the data center service restoration responsiveness to the dynamic end-to-end service demands. We quantitatively evaluate the feasibility and performances through the simulation under heavy traffic load scenario in terms of path blocking probability and path restoration latency. Numeric results show that the cross-layer restoration scheme improves the recovery success rate and minimizes the overall recovery time.

  18. Long Range Transport of War-Related Burn Casualties

    DTIC Science & Technology

    2008-02-01

    ted to the Army’s burn center between March 2003 and February 2007. Data in- cluded total body surface area (TBSA) burn, ventilatory status... total body surface area (range, ə%–95%) with a mean Injury Severity Score of 12.2 13.7. One hundred eight-one (33.5%) casualties required venti...Long Range Transport of War-Related Burn Casualties 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT

  19. Sediment transport under wave groups: Relative importance between nonlinear waveshape and nonlinear boundary layer streaming

    USGS Publications Warehouse

    Yu, X.; Hsu, T.-J.; Hanes, D.M.

    2010-01-01

    Sediment transport under nonlinear waves in a predominately sheet flow condition is investigated using a two-phase model. Specifically, we study the relative importance between the nonlinear waveshape and nonlinear boundary layer streaming on cross-shore sand transport. Terms in the governing equations because of the nonlinear boundary layer process are included in this one-dimensional vertical (1DV) model by simplifying the two-dimensional vertical (2DV) ensemble-averaged two-phase equations with the assumption that waves propagate without changing their form. The model is first driven by measured time series of near-bed flow velocity because of a wave group during the SISTEX99 large wave flume experiment and validated with the measured sand concentration in the sheet flow layer. Additional studies are then carried out by including and excluding the nonlinear boundary layer terms. It is found that for the grain diameter (0.24 mm) and high-velocity skewness wave condition considered here, nonlinear waveshape (e.g., skewness) is the dominant mechanism causing net onshore transport and nonlinear boundary layer streaming effect only causes an additional 36% onshore transport. However, for conditions of relatively low-wave skewness and a stronger offshore directed current, nonlinear boundary layer streaming plays a more critical role in determining the net transport. Numerical experiments further suggest that the nonlinear boundary layer streaming effect becomes increasingly important for finer grain. When the numerical model is driven by measured near-bed flow velocity in a more realistic surf zone setting, model results suggest nonlinear boundary layer processes may nearly double the onshore transport purely because of nonlinear waveshape. Copyright 2010 by the American Geophysical Union.

  20. High-frequency limit of the transport cross section in scattering by an obstacle with impedance boundary conditions

    NASA Astrophysics Data System (ADS)

    Aleksenko, A. I.; Cruz, J. P.; Lakshtanov, E. L.

    2008-06-01

    The scalar scattering of a plane wave by a strictly convex obstacle with impedance boundary conditions is considered. A uniform bound of the total cross section for all values of the frequency is presented. The high-frequency limit of the transport cross section is calculated and presented as a classical functional of the variational calculus.

  1. Neighborhood walkability, physical activity, and walking for transportation: A cross-sectional study of older adults living on low income.

    PubMed

    Chudyk, Anna M; McKay, Heather A; Winters, Meghan; Sims-Gould, Joanie; Ashe, Maureen C

    2017-04-10

    Walking, and in particular, outdoor walking, is the most common form of physical activity for older adults. To date, no study investigated the association between the neighborhood built environment and physical activity habits of older adults of low SES. Thus, our overarching aim was to examine the association between the neighborhood built environment and the spectrum of physical activity and walking for transportation in older adults of low socioeconomic status. Cross-sectional data were from the Walk the Talk Study, collected in 2012. Participants (n = 161, mean age = 74 years) were in receipt of a rental subsidy for low income individuals and resided in neighbourhoods across Metro Vancouver, Canada. We used the Street Smart Walk Score to objectively characterize the built environment main effect (walkability), accelerometry for objective physical activity, and the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire to measure walking for transportation. We used regression analyses to examine associations of objectively measured physical activity [total volume, light intensity and moderate intensity physical activity (MVPA)] and self-reported walking for transportation (any, frequency, duration) with walkability. We adjusted analyses for person- and environment-level factors associated with older adult physical activity. Neighbourhood walkability was not associated with physical activity volume or intensity and self-reported walking for transportation, with one exception. Each 10-point increase in Street Smart Walk Score was associated with a 45% greater odds of any walking for transportation (compared with none; OR = 1.45, 95% confidence interval = 1.18, 1.78). Sociodemographic, physical function and attitudinal factors were significant predictors of physical activity across our models. The lack of associations between most of the explored outcomes may be due to the complexity of the relation between the person and

  2. Border Crossings: Engaging Students in Diversity Work and Intergroup Relations

    ERIC Educational Resources Information Center

    Rose, Susan D.; Bylander, Joyce

    2007-01-01

    As an innovative model for diversity education, Dickinson College designed the "Crossing Borders" program to encourage culturally diverse students to live, work, and study together in multiple contexts both within the United States and abroad. Envisioning a series of crossings, the program brings together up to 20 students from Dickinson…

  3. Sudden clearing of estuarine waters upon crossing the threshold from transport to supply regulation of sediment transport as an erodible sediment pool is depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, David H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991–1998 to 1999–2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing.

  4. An advection-diffusion model for cross-field runaway electron transport in perturbed magnetic fields

    NASA Astrophysics Data System (ADS)

    Särkimäki, Konsta; Hirvijoki, Eero; Decker, Joan; Varje, Jari; Kurki-Suonio, Taina

    2016-12-01

    Disruption-generated runaway electrons (RE) present an outstanding issue for ITER. The predictive computational studies of RE generation rely on orbit-averaged computations and, as such, they lack the effects from the magnetic field stochasticity. Since stochasticity is naturally present in post-disruption plasma, and externally induced stochastization offers a prominent mechanism to mitigate RE avalanche, we present an advection-diffusion model that can be used to couple an orbit-following code to an orbit-averaged tool in order to capture the cross-field transport and to overcome the latter’s limitation. The transport coefficients are evaluated via a Monte Carlo method. We show that the diffusion coefficient differs significantly from the well-known Rechester-Rosenbluth result. We also demonstrate the importance of including the advection: it has a two-fold role both in modelling transport barriers created by magnetic islands and in amplifying losses in regions where the islands are not present.

  5. Cross-field electron transport induced by a rotating spoke in a cylindrical Hall thruster

    NASA Astrophysics Data System (ADS)

    Ellison, C. L.; Raitses, Y.; Fisch, N. J.

    2012-01-01

    Rotating spoke phenomena have been observed in a variety of Hall thruster and other E × B devices. It has been suggested that the spoke may be associated with the enhancement of the electron cross-field transport. In this paper, the current conducted across the magnetic field via a rotating spoke has been directly measured for the first time in the E × B discharge of a cylindrical Hall thruster. The spoke current was measured using a segmented anode. Synchronized measurements with a high speed camera and a four-segment anode allow observation of the current as a function of time and azimuthal position. Upwards of 50% of the total current is conducted through the spoke, which occupies a quarter of the Hall thruster channel area. To determine the transport mechanism, emissive and Langmuir probes were installed to measure fluctuating plasma potential, electron density, and temperature. A perturbed, azimuthal electric field and density are observed to oscillate in-phase with the rotating spoke. The resulting drift current is found to enhance electron transport with a magnitude equal to the spoke current to within margins of error.

  6. CrossFit-related cervical internal carotid artery dissection.

    PubMed

    Lu, Albert; Shen, Peter; Lee, Paul; Dahlin, Brian; Waldau, Ben; Nidecker, Anna E; Nundkumar, Anoop; Bobinski, Matthew

    2015-08-01

    CrossFit is a high-intensity strength and conditioning program that has gained popularity over the past decade. Potential injuries associated with CrossFit training have been suggested in past reports. We report three cases of cervical carotid dissection that are associated with CrossFit workouts. Patient 1 suffered a distal cervical internal carotid artery (ICA) dissection near the skull base and a small infarct in Wernicke's area. He was placed on anticoagulation and on follow-up has near complete recovery. Patient 2 suffered a proximal cervical ICA dissection that led to arterial occlusion and recurrent middle cerebral artery territory infarcts and significant neurological sequelae. Patient 3 had a skull base ICA dissection that led to a partial Horner's syndrome but no cerebral infarct. While direct causality cannot be proven, intense CrossFit workouts may have led to the ICA dissections in these patients.

  7. Direct relations between morphology and transport in Boolean models.

    PubMed

    Scholz, Christian; Wirner, Frank; Klatt, Michael A; Hirneise, Daniel; Schröder-Turk, Gerd E; Mecke, Klaus; Bechinger, Clemens

    2015-10-01

    We study the relation of permeability and morphology for porous structures composed of randomly placed overlapping circular or elliptical grains, so-called Boolean models. Microfluidic experiments and lattice Boltzmann simulations allow us to evaluate a power-law relation between the Euler characteristic of the conducting phase and its permeability. Moreover, this relation is so far only directly applicable to structures composed of overlapping grains where the grain density is known a priori. We develop a generalization to arbitrary structures modeled by Boolean models and characterized by Minkowski functionals. This generalization works well for the permeability of the void phase in systems with overlapping grains, but systematic deviations are found if the grain phase is transporting the fluid. In the latter case our analysis reveals a significant dependence on the spatial discretization of the porous structure, in particular the occurrence of single isolated pixels. To link the results to percolation theory we performed Monte Carlo simulations of the Euler characteristic of the open cluster, which reveals different regimes of applicability for our permeability-morphology relations close to and far away from the percolation threshold.

  8. Direct relations between morphology and transport in Boolean models

    NASA Astrophysics Data System (ADS)

    Scholz, Christian; Wirner, Frank; Klatt, Michael A.; Hirneise, Daniel; Schröder-Turk, Gerd E.; Mecke, Klaus; Bechinger, Clemens

    2015-10-01

    We study the relation of permeability and morphology for porous structures composed of randomly placed overlapping circular or elliptical grains, so-called Boolean models. Microfluidic experiments and lattice Boltzmann simulations allow us to evaluate a power-law relation between the Euler characteristic of the conducting phase and its permeability. Moreover, this relation is so far only directly applicable to structures composed of overlapping grains where the grain density is known a priori. We develop a generalization to arbitrary structures modeled by Boolean models and characterized by Minkowski functionals. This generalization works well for the permeability of the void phase in systems with overlapping grains, but systematic deviations are found if the grain phase is transporting the fluid. In the latter case our analysis reveals a significant dependence on the spatial discretization of the porous structure, in particular the occurrence of single isolated pixels. To link the results to percolation theory we performed Monte Carlo simulations of the Euler characteristic of the open cluster, which reveals different regimes of applicability for our permeability-morphology relations close to and far away from the percolation threshold.

  9. The effect of cross-sectional velocity and concentration variations on suspended sediment transport rates in tidal creeks

    NASA Astrophysics Data System (ADS)

    Pillay, Seane; Gardner, L. R.; Kjerfve, Björn

    1992-10-01

    Instantaneous suspended sediment transport rates over numerous tidal cycles have been determined for two tidal creeks in South Carolina: Town Creek, North Inlet, and Bass Creek, Kiawah Island. Three different calculation methods were employed: (1) area-integrated product of sediment concentration, velocity, and sample subarea (Method I, the true transport rate); (2) product of instantaneous channel cross-section area, cross-sectionally averaged velocity, and cross-sectionally averaged concentration (Method II); and (3) product of instantaneous discharge and sediment concentration at a single, near-surface, mid-channel sample location (Method III). Logistical and financial constraints at times dictate use of Method III rather than the more rigorous Method I. Deviations between Method II (and/or III) and Method I as a percentage of the Method I transport rates can be large (up to 120%). Fortunately the largest percent deviations occur at times of low Method I transport. As a result, linear regressions of Method I transport rates against those of Methods II or III yield correlation coefficients r2 > 0·9. Thus Method II or III transport rates can be corrected by regression analysis to give reliable estimates of the Method I transport rate. Accordingly, it may be possible to calculate tidal residual suspended sediment transport rates for the Long-Term Ecological Research (LTER) site at North Inlet using daily water sample data, providing an accurate hypsometric model can be developed for estimating instantaneous discharge from continuous tide data.

  10. Effects of Anomalous Electron Cross-Field Transport in a Low Temperature Magnetized Plasma

    NASA Astrophysics Data System (ADS)

    Raitses, Yevgeny

    2014-10-01

    The application of the magnetic field in a low pressure plasma can cause a spatial separation of low and high energy electrons. This so-called magnetic filter effect is used for many plasma applications, including ion and neutral beam sources, plasma processing of semiconductors and nanomaterials, and plasma thrusters. In spite of successful practical applications, the magnetic filter effect is not well understood. In this work, we explore this effect by characterizing the electron and ion energy distribution functions in a plasma column with crossed electric and magnetic fields. Experimental results revealed a strong dependence of spatial variations of plasma properties on the gas pressure. For xenon and argon gases, below ~ 1 mtorr, the increase of the magnetic field leads to a more uniform profile of the electron temperature. This surprising result is due to anomalously high electron cross-field transport that causes mixing of hot and cold electrons. High-speed imaging and probe measurements revealed a coherent structure rotating in E cross B direction with frequency of a few kHz. Theory and simulations describing this rotating structure has been developed and points to ionization and electrostatic instabilities as their possible cause. Similar to spoke oscillations reported for Hall thrusters, this rotating structure conducts the large fraction of the cross-field current. The use of segmented electrodes with an electrical feedback control is shown to mitigate these oscillations. Finally, a new feature of the spoke phenomenon that has been discovered, namely a sensitive dependence of the rotating oscillations on the gas pressure, can be important for many applications. This work was supported by DOE Contract DE-AC02-09CH11466.

  11. Cumulative relative reactivity: A concept for modeling aquifer-scale reactive transport

    NASA Astrophysics Data System (ADS)

    Loschko, Matthias; Wöhling, Thomas; Rudolph, David L.; Cirpka, Olaf A.

    2016-10-01

    We simulate aquifer-scale reactive transport using an approach based on travel times and relative reactivity. The latter quantifies the intensity of the chemical reaction relative to a reference reaction rate with identical concentrations and can be interpreted as the strength of electron-donor (or electron-acceptor) release by the matrix, scaled by a reference release. In general, the relative reactivity is a spatially variable property reflecting the geology of the formation. In the proposed approach, we track the path of individual water parcels through the aquifer and evaluate the age of the water parcels and the relative reactivity integrated along their trajectories. By switching from spatial discretization to cumulative relative reactivity, advective-reactive transport can be simulated by solving a single system of ordinary differential equations for each combination of concentrations in the inflow. We test the validity of the approach in a two-dimensional test case of steady state groundwater flow and reactive transport involving aerobic respiration and denitrification. Here we compare steady state concentration distributions of the spatially explicit virtual truth, accounting for dispersive mixing, with the approximation based on cumulative relative reactivity and show that the errors introduced by neglecting dispersive mixing are minor if the target quantities are the mass fluxes crossing a control plane or being collected by a well. We further demonstrate the efficiency of the approach in a synthetic three-dimensional case study. The proposed approach is computationally so efficient that ensemble runs to assess statistical distributions of concentration time series of reactive solutes become feasible, which is not practical with a spatially explicit model.

  12. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  13. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  14. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  15. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  16. How Space Radiation Risk from Galactic Cosmic Rays at the International Space Station Relates to Nuclear Cross Sections

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Adams, J. H., Jr.

    2005-01-01

    Space radiation risk to astronauts is a major obstacle for long term human space explorations. Space radiation transport codes have thus been developed to evaluate radiation effects at the International Space Station (ISS) and in missions to the Moon or Mars. We study how nuclear fragmentation processes in such radiation transport affect predictions on the radiation risk from galactic cosmic rays. Taking into account effects of the geomagnetic field on the cosmic ray spectra, we investigate the effects of fragmentation cross sections at different energies on the radiation risk (represented by dose-equivalent) from galactic cosmic rays behind typical spacecraft materials. These results tell us how the radiation risk at the ISS is related to nuclear cross sections at different energies, and consequently how to most efficiently reduce the physical uncertainty in our predictions on the radiation risk at the ISS.

  17. Peristaltic transport of a biofluid in a pipe of elliptic cross section.

    PubMed

    Usha, S; Rao, A R

    1995-01-01

    Peristaltic transport of two fluids occupying the peripheral layer and the core in an elliptic tube is investigated in elliptic cylindrical co-ordinate system, under long wavelength and low Reynolds number approximations. The effect of peripheral-layer viscosity on the flow rate and the frictional force for a slightly elliptic tube is discussed. The limiting results for the one-fluid model are obtained for different eccentricities of the undisturbed tube cross sections with the same area. As a result of non-uniformity of the peristaltic wave, two different amplitude ratios are defined and the time-averaged flux and mechanical efficiency are studied for different eccentricities. It is observed that the time-averaged flux is not affected significantly by the pressure drop when the eccentricity is large. For the peristaltic waves with same area variation, the pumping seems to improve with the eccentricity.

  18. Identification of Measures Related to Cross-Cultural Competence

    DTIC Science & Technology

    2008-01-01

    5. Task role behaviors - contribute to group problem-solving activities Results of the administration of the BASIC measure to 263 college...mental health systems and agencies wish to hire culturally competent providers and to train their providers to be culturally competent (Sue, 2003...hypothesized predictors, or antecedents, of behavior , such as personality traits. These Cognitive Performance Group Review of Cross Cultural Competence

  19. Diverse relations between ABC transporters and lipids: An overview.

    PubMed

    Neumann, Jennifer; Rose-Sperling, Dania; Hellmich, Ute A

    2017-04-01

    It was first discovered in 1992 that P-glycoprotein (Pgp, ABCB1), an ATP binding cassette (ABC) transporter, can transport phospholipids such as phosphatidylcholine, -ethanolamine and -serine as well as glucosylceramide and glycosphingolipids. Subsequently, many other ABC transporters were identified to act as lipid transporters. For substrate transport by ABC transporters, typically a classic, alternating access model with an ATP-dependent conformational switch between a high and a low affinity substrate binding site is evoked. Transport of small hydrophilic substrates can easily be imagined this way, as the molecule can in principle enter and exit the transporter in the same orientation. Lipids on the other hand need to undergo a 180° degree turn as they translocate from one membrane leaflet to the other. Lipids and lipidated molecules are highly diverse, so there may be various ways how to achieve their flipping and flopping. Nonetheless, an increase in biophysical, biochemical and structural data is beginning to shed some light on specific aspects of lipid transport by ABC transporters. In addition, there is now abundant evidence that lipids affect ABC transporter conformation, dynamics as well as transport and ATPase activity in general. In this review, we will discuss different ways in which lipids and ABC transporters interact and how lipid translocation may be achieved with a focus on the techniques used to investigate these processes. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Crossed Andreev Reflection and Spin-Resolved Non-local Electron Transport

    NASA Astrophysics Data System (ADS)

    Kalenkov, Mikhail S.; Zaikin, Andrei D.

    The phenomenon of crossed Andreev reflection (CAR) is known to play a key role in non-local electron transport across three-terminal normal-superconducting-normal (NSN) devices. Here, we review our general theory of non-local charge transport in three-terminal disordered ferromagnet-superconductor-ferromagnet (FSF) structures. We demonstrate that CAR is highly sensitive to electron spins and yields a rich variety of properties of non-local conductance, which we describe non-perturbatively at arbitrary voltages, temperature, degree of disorder, spin-dependent interface transmissions and their polarizations. We demonstrate that magnetic effects have different implications: While strong exchange field suppresses disorder-induced electron interference in ferromagnetic electrodes, spin-sensitive electron scattering at SF interfaces can drive the total non-local conductance negative at sufficiently low energies. At higher energies, magnetic effects become less important and the non-local resistance behaves similarly to the non-magnetic case. Our results can be applied to multi-terminal hybrid structures with normal, ferromagnetic and half-metallic electrodes and can be directly tested in future experiments.

  1. Semi-empirical inelastic cross sections for electron transport in liquid water.

    PubMed

    Emfietzoglou, D

    2002-01-01

    Electron inelastic cross sections for water in the liquid phase are important for developing Monte Carlo codes that simulate the full degradation of any radiation beam in biological matter. The limited experimental information for condensed targets and the complexity of the background theory has led to largely heuristic semi-empirical models. The present work makes use of the dielectric formalism under the first Born approximation to develop inelastic cross sections for low-energy electron transport in liquid water. A Drude model was used to describe the energy-loss distribution at the dipole limit on the basis of optical data, while the impulse approximation and an empirical generalised-oscillator-strength provided the extension to finite momentum transfer. Born corrections established earlier for water vapour were applied at low impact energies. Core-electron transitions were treated by a binary model with exchange terms. Sum-rules were satisfied to within 1-2% while an 1-value of about 80 eV was obtained. A comparison with other studies is provided.

  2. The transport of octamethylcyclotetrasiloxane (D4) and polydimethylsiloxane (PDMS) in lightly cross-linked silicone rubber.

    PubMed

    Wolf, C J; Jerina, K L; Brandon, H J; Young, V L

    2001-01-01

    The transport of octamethylcyclotetrasiloxane (D4), one of the major constituents of silicone fluids and rubbers, and low viscosity polydimethylsiloxane oil into a silica filled cross-linked silicone elastomeric rubber was measured as a function of temperature, cross-link density of the rubber, and concentration of the D4 in methanol solution. A small amount of material, approximately 3 wt%, is extracted from the rubber with hexane. The extraction process has a large effect upon D4 solubility in the rubber, increasing from approximately 160 to 180 wt% after extraction. The heats of solution for both penetrants into the rubber are essentially zero and the activation energies for diffusion are small, approximately 8 and 15 kJ molt(-1) for D4 and PDMS, respectively. The diffusion process is Fickian and the diffusion coefficient of D4 into silicone/silica rubbers is essentially independent of concentration over the concentration investigated, i.e. from 1 to 100 vol% D4 in methanol. The permeability, i.e. the product of the diffusion coefficient and the solubility, decreases rapidly for D4 concentrations less than 50 vol% (0.1 mol fraction). This suggests that the permeation of D4 out of any encapsulation device, such as a silicone breast implant, is linearly dependent upon the concentration of D4 in the prosthesis. Swelling is isotropic and was measured by dimensional changes in rectangular samples and correlates well with the volume of D4 sorbed.

  3. Electron Transport Coefficients and Scattering Cross Sections in CH4, HBr and in Mixtures of He and Xe

    SciTech Connect

    Sasic, Olivera M.

    2006-12-01

    We have applied a standard swarm procedure in order to obtain electron scattering cross sections and transport coefficients that provide a data base for plasma modeling. In case of CH4 the dissociative excitation cross sections from binary collision experiments were renormalized by fitting the measured excitation coefficients with our calculations. In case of HBr we have produced a complete set of cross sections based on available data from the literature, with some extrapolations. We have also tested the cross sections in He-Xe mixtures and the application of Blanc's law and common mean energy procedure in calculating drift velocities in by comparison with recent measurements. Finally, a well tested Monte Carlo code was used in wide range of both DC and RF electric and magnetic fields in order to calculate a number of transport coefficients in case of CH4 and HBr.

  4. Using Beryllium-7 to Assess Cross-Tropopause Transport in Global Models

    NASA Astrophysics Data System (ADS)

    Liu, H.; Considine, D.

    2007-12-01

    The stratosphere-troposphere exchange (STE) flux of ozone plays an important role in the tropospheric ozone budget. Representing this flux in global models is critical to quantitatively understanding the tropospheric ozone budget. Beryllium-7 (7Be), produced cosmogenically in the stratosphere and upper troposphere, has long been used to determine the stratospheric origin of tropospheric air. Here we use the Global Modeling Initiative (GMI) modeling framework to assess the utility of 7Be for evaluating STE in global models. The GMI chemistry and transport model (CTM) was used to simulate atmospheric 7Be distributions using four different meteorological data sets, featuring significantly different STE characteristics. The data sets were generated by the Goddard Space Flight Center Global Modeling and Assimilation Office (GMAO) GEOS-STRAT assimilation, the Goddard Institute for Space Studies GISS II' general circulation model (GISS II' GCM), the GMAO finite-volume GCM (fvGCM), and the GMAO GEOS-4 data assimilation system (GEOS-4 DAS). The simulations were compared with observed 7Be concentrations at the surface and in the upper troposphere / lower stratosphere (UT/LS), as well as surface deposition fluxes. The UT/LS observations are climatologies constructed from ~25 years of aircraft and balloon data from the US Environmental Measurements Laboratory RANDAB database. All simulations capture the observations at 12-16km, but underestimate concentrations at higher altitudes, especially at Northern Hemisphere middle/high latitudes with GEOS-STRAT. Comparison of the surface fraction of air of stratospheric origin estimated from the 7Be simulations with observationally-derived estimates indicates excessive cross-tropopause transport at middle latitudes in simulations using GEOS-STRAT and at high latitudes using GISS II' meteorological data. These simulations also overestimate 7Be deposition flux at middle latitudes (GEOS-STRAT) and at high latitudes (GISS II'). We conclude

  5. Cross-Scale Energy Transport and Kinetic Wave Properties Associated with Kelvin-Helmholtz Instability

    NASA Astrophysics Data System (ADS)

    Moore, Thomas W.

    In the Earth's magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn-sector, the cold-component ions are more abundant and hotter by 30-40 percent when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetry of the magnetosheath is unable to account for this (Dimmock et al., 2015), so additional physical mechanisms must be at play, either at the magnetopause or plasma sheet, that contribute to this asymmetry. This thesis focuses on ion heating across the magnetopause boundary separating the magnetosheath and the magnetospheric plasmas, which is driven by mechanisms operating on fluid, ion and electron scales. One of the pending problems in collisionless astrophysical plasmas is to understand the plasma heating and transport across three fundamental scales: fluid, ion and electron. Presented here is evidence of the energy transport between the fluid and ion scales: energy is provided by a velocity shear at the magnetopause generating fluid-scale Kelvin-Helmholtz Instability and their rolled-up vortices, where an ion-scale fast magnetosonic wave packet located in the center of a Kelvin-Helmholtz vortex has sufficient energy to account for observed cold-component ion heating. In addition, a statistical analysis is performed on the ion-scale wave properties in the three main plasma regimes common to flank magnetopause boundary crossings when the boundary is unstable to KHI: hot and tenuous magnetospheric, cold and dense magnetosheath and mixed (H. Hasegawa, Fujimoto, Phan, et al., 2004). The statistical analysis shows that during KH events there is enhanced non-adiabatic heating calculated during ion scale wave intervals when compared to non-KH events. This suggests that during KH events there is more free energy for ion-scale wave generation, which in turn can heat ions more effectively when compared to cases when KH

  6. Observational constraints on atmospheric and oceanic cross-equatorial heat transports: revisiting the precipitation asymmetry problem in climate models

    NASA Astrophysics Data System (ADS)

    Loeb, Norman G.; Wang, Hailan; Cheng, Anning; Kato, Seiji; Fasullo, John T.; Xu, Kuan-Man; Allan, Richard P.

    2016-05-01

    Satellite based top-of-atmosphere (TOA) and surface radiation budget observations are combined with mass corrected vertically integrated atmospheric energy divergence and tendency from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Hemispheric contrasts in the energy budget terms are used to determine the radiative and combined sensible and latent heat contributions to the cross-equatorial heat transports in the atmosphere (AHTEQ) and ocean (OHTEQ). The contrast in net atmospheric radiation implies an AHTEQ from the northern hemisphere (NH) to the southern hemisphere (SH) (0.75 PW), while the hemispheric difference in sensible and latent heat implies an AHTEQ in the opposite direction (0.51 PW), resulting in a net NH to SH AHTEQ (0.24 PW). At the surface, the hemispheric contrast in the radiative component (0.95 PW) dominates, implying a 0.44 PW SH to NH OHTEQ. Coupled model intercomparison project phase 5 (CMIP5) models with excessive net downward surface radiation and surface-to-atmosphere sensible and latent heat transport in the SH relative to the NH exhibit anomalous northward AHTEQ and overestimate SH tropical precipitation. The hemispheric bias in net surface radiative flux is due to too much longwave surface radiative cooling in the NH tropics in both clear and all-sky conditions and excessive shortwave surface radiation in the SH subtropics and extratropics due to an underestimation in reflection by clouds.

  7. Physical activity in relation to urban environments in 14 cities worldwide: a cross-sectional study.

    PubMed

    Sallis, James F; Cerin, Ester; Conway, Terry L; Adams, Marc A; Frank, Lawrence D; Pratt, Michael; Salvo, Deborah; Schipperijn, Jasper; Smith, Graham; Cain, Kelli L; Davey, Rachel; Kerr, Jacqueline; Lai, Poh-Chin; Mitáš, Josef; Reis, Rodrigo; Sarmiento, Olga L; Schofield, Grant; Troelsen, Jens; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Owen, Neville

    2016-05-28

    Physical inactivity is a global pandemic responsible for over 5 million deaths annually through its effects on multiple non-communicable diseases. We aimed to document how objectively measured attributes of the urban environment are related to objectively measured physical activity, in an international sample of adults. We based our analyses on the International Physical activity and Environment Network (IPEN) adult study, which was a coordinated, international, cross-sectional study. Participants were sampled from neighbourhoods with varied levels of walkability and socioeconomic status. The present analyses of data from the IPEN adult study included 6822 adults aged 18-66 years from 14 cities in ten countries on five continents. Indicators of walkability, public transport access, and park access were assessed in 1·0 km and 0·5 km street network buffers around each participant's residential address with geographic information systems. Mean daily minutes of moderate-to-vigorous-intensity physical activity were measured with 4-7 days of accelerometer monitoring. Associations between environmental attributes and physical activity were estimated using generalised additive mixed models with gamma variance and logarithmic link functions. Four of six environmental attributes were significantly, positively, and linearly related to physical activity in the single variable models: net residential density (exp[b] 1·006 [95% CI 1·003-1·009]; p=0·001), intersection density (1·069 [1·011-1·130]; p=0·019), public transport density (1·037 [1·018-1·056]; p=0·0007), and number of parks (1·146 [1·033-1·272]; p=0·010). Mixed land use and distance to nearest public transport point were not related to physical activity. The difference in physical activity between participants living in the most and least activity-friendly neighbourhoods ranged from 68 min/week to 89 min/week, which represents 45-59% of the 150 min/week recommended by guidelines. Design of urban

  8. Molecular motions involved in Na-K-Cl cotransporter-mediated ion transport and transporter activation revealed by internal cross-linking between transmembrane domains 10 and 11/12.

    PubMed

    Monette, Michelle Y; Somasekharan, Suma; Forbush, Biff

    2014-03-14

    We examined the relationship between transmembrane domain (TM) 10 and TM11/12 in NKCC1, testing homology models based on the structure of AdiC in the same transporter superfamily. We hypothesized that introduced cysteine pairs would be close enough for disulfide formation and would alter transport function: indeed, evidence for cross-link formation with low micromolar concentrations of copper phenanthroline or iodine was found in 3 of 8 initially tested pairs and in 1 of 26 additionally tested pairs. Inhibition of transport was observed with copper phenanthroline and iodine treatment of P676C/A734C and I677C/A734C, consistent with the proximity of these residues and with movement of TM10 during the occlusion step of ion transport. We also found Cu(2+) inhibition of the single-cysteine mutant A675C, suggesting that this residue and Met(382) of TM3 are involved in a Cu(2+)-binding site. Surprisingly, cross-linking of P676C/I730C was found to prevent rapid deactivation of the transporter while not affecting the dephosphorylation rate, thus uncoupling the phosphorylation and activation steps. Consistent with this, (a) cross-linking of P676C/I730C was dependent on activation state, and (b) mutants lacking the phosphoregulatory domain could still be activated by cross-linking. These results suggest a model of NKCC activation that involves movement of TM12 relative to TM10, which is likely tied to movement of the large C terminus, a process somehow triggered by phosphorylation of the regulatory domain in the N terminus.

  9. Sediment transport patterns in the San Francisco Bay Coastal System from cross-validation of bedform asymmetry and modeled residual flux

    USGS Publications Warehouse

    Barnard, Patrick L.; Erikson, Li H.; Elias, Edwin P.L.; Dartnell, Peter; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    The morphology of ~ 45,000 bedforms from 13 multibeam bathymetry surveys was used as a proxy for identifying net bedload sediment transport directions and pathways throughout the San Francisco Bay estuary and adjacent outer coast. The spatially-averaged shape asymmetry of the bedforms reveals distinct pathways of ebb and flood transport. Additionally, the region-wide, ebb-oriented asymmetry of 5% suggests net seaward-directed transport within the estuarine-coastal system, with significant seaward asymmetry at the mouth of San Francisco Bay (11%), through the northern reaches of the Bay (7–8%), and among the largest bedforms (21% for λ > 50 m). This general indication for the net transport of sand to the open coast strongly suggests that anthropogenic removal of sediment from the estuary, particularly along clearly defined seaward transport pathways, will limit the supply of sand to chronically eroding, open-coast beaches. The bedform asymmetry measurements significantly agree (up to ~ 76%) with modeled annual residual transport directions derived from a hydrodynamically-calibrated numerical model, and the orientation of adjacent, flow-sculpted seafloor features such as mega-flute structures, providing a comprehensive validation of the technique. The methods described in this paper to determine well-defined, cross-validated sediment transport pathways can be applied to estuarine-coastal systems globally where bedforms are present. The results can inform and improve regional sediment management practices to more efficiently utilize often limited sediment resources and mitigate current and future sediment supply-related impacts.

  10. Sediment transport patterns in the San Francisco Bay Coastal System from cross-validation of bedform asymmetry and modeled residual flux

    USGS Publications Warehouse

    Barnard, Patrick L.; Erikson, Li H.; Elias, Edwin P.L.; Dartnell, Peter

    2013-01-01

    The morphology of ~ 45,000 bedforms from 13 multibeam bathymetry surveys was used as a proxy for identifying net bedload sediment transport directions and pathways throughout the San Francisco Bay estuary and adjacent outer coast. The spatially-averaged shape asymmetry of the bedforms reveals distinct pathways of ebb and flood transport. Additionally, the region-wide, ebb-oriented asymmetry of 5% suggests net seaward-directed transport within the estuarine-coastal system, with significant seaward asymmetry at the mouth of San Francisco Bay (11%), through the northern reaches of the Bay (7-8%), and among the largest bedforms (21% for λ > 50 m). This general indication for the net transport of sand to the open coast strongly suggests that anthropogenic removal of sediment from the estuary, particularly along clearly defined seaward transport pathways, will limit the supply of sand to chronically eroding, open-coast beaches. The bedform asymmetry measurements significantly agree (up to ~ 76%) with modeled annual residual transport directions derived from a hydrodynamically-calibrated numerical model, and the orientation of adjacent, flow-sculpted seafloor features such as mega-flute structures, providing a comprehensive validation of the technique. The methods described in this paper to determine well-defined, cross-validated sediment transport pathways can be applied to estuarine-coastal systems globally where bedforms are present. The results can inform and improve regional sediment management practices to more efficiently utilize often limited sediment resources and mitigate current and future sediment supply-related impacts.

  11. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... criticality safety indices. 176.704 Section 176.704 Transportation Other Regulations Relating to... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport indices... not apply to consignments of LSA-I material. (d) The sum of the criticality safety indices (CSI's)...

  12. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... criticality safety indices. 176.704 Section 176.704 Transportation Other Regulations Relating to... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport indices... not apply to consignments of LSA-I material. (d) The sum of the criticality safety indices (CSI's)...

  13. Sediment transport-storage relations for degrading, gravel bed channels

    Treesearch

    Thomas E. Lisle; Michael Church

    2002-01-01

    In a drainage network,sediment is transferred through a series of channel/valley segments (natural sediment storage reservoirs) that are distinguished from their neighbors by their particular capacity to store and transport sediment. We propose that the sediment transport capacity of each reservoir is a unique positive function of storage volume, which influences...

  14. Cosmogenic nuclide shielding corrections determined via MCNPX radiation transport and spallation cross sections

    NASA Astrophysics Data System (ADS)

    Argento, D.; Reedy, R. C.; Stone, J. O.

    2011-12-01

    Cosmogenic Nuclides (CNs) are a critical new tool for geomorphology, allowing researchers to date Earth surface events and measure process rates [1]. Prior to CNs, many of these events and processes had no absolute method for measurement and relied entirely on relative methods. Reliable absolute measurement methods impact research constraining ice age extents and provide important climatic data via well constrained erosion rates, etc. [2]. Continuing to improve CN methods is critical for these sciences. Significant progress has been made in the last two decades in refining the method and reducing analytic uncertainties [1,3]. CRONUS-Earth, a collaboration of cosmogenic nuclide researchers, has been developing calibration data and scaling methods to provide a self-consistent platform for use in interpreting nuclide concentration values into geologic data. However, several aspects of the radiation cascade have been exceedingly difficult to measure empirically with either accuracy or spatial extent. One such aspect is the angular distribution of secondary cosmic rays that are energetic enough to produce cosmogenic nuclides via spallation. Researchers studying the angular distribution of such cosmic rays have usually described the distribution as (cos(Θ))^m. Currently, the standard corrections, assume an m of 2.3, which is based on very sparse data sets with very limited spatial and altitude variation [1,4,5]. Researchers using CNs must know the production rate at the sample location, and then make corrections for the portion of the sky that is blocked by nearby topography. If the shielding correction model currently used is too simplistic, this introduces error into the final results. In this study, a Monte Carlo method radiation transport code, MCNPX is used to model the Galactic Cosmic Ray (GCR) radiation impinging on the upper atmosphere and tracks the resulting secondary particles through a model of the Earth's atmosphere. Angle and energy distributions are

  15. Relating climate and sand transport to incipient dune development.

    NASA Astrophysics Data System (ADS)

    van Puijenbroek, Marinka; Limpens, Juul; Gleichman, Maurits; Berendse, Frank

    2014-05-01

    Sea levels are continuously rising, increasing the risk of flooding and coastal erosion in low-elevation countries, such as the Netherlands. Coastal dunes are seen as a flexible and natural type of coastal defence, that is able to keep pace with rising water levels. Until now most research has focussed on dynamics and maintenance of established dunes, largely ignoring two critical transitions in early dune development: the transition from bare beach to vegetated incipient dune and that from incipient dune to established foredune. This knowledge is essential to enable more accurate prediction and even stimulation of new dune formation through sand nourishment. We explored the relative contributions of climate and sand transport to incipient dune development combining a 30 year time-series of aerial photographs (1979 - 2010) of the natural Wadden Island coast with high-resolution monitoring data of sand volume changes and climatic parameters. We selected 20 strips of 2.5 km in length along the coast of the Wadden Islands, with a 2 km buffer between them to avoid autocorrelation. For each of these strips of coast we assessed the changes in presence and area of incipient dunes over periods of 5-6 years. Change in fore dune volume and beach width were derived from high resolution beach elevation data. Seawater level and climate data were derived from a nearby meteorological station Preliminary analysis of the first half of the dataset showed that incipient dune area was positively related to beach width, but negatively to storm intensity. In our poster we will present the whole dataset and discuss the implications of our results for future dune development and anthropogenic sand nourishment schemes.

  16. Transport in MultiTerminal Normal-Superconductor Devices: Reciprocity Relations, Negative and Nonlocal Resistances, and Reentrance of the Proximity Effect

    SciTech Connect

    den Hartog, S.; Kapteyn, C.; van Wees, B.; Klapwijk, T.; Borghs, G.

    1996-12-01

    We have investigated transport in a cross-shaped two-dimensional electron gas with superconducting electrodes coupled to two opposite arms. Multiterminal resistances, measured as a function of the superconducting phase difference and the magnetic flux, are analyzed in terms of an extended Landauer-B{umlt u}ttiker transport formalism. We show that extended reciprocity relations hold. Correlations between transport coefficients are obtained from, e.g., (negative) three-terminal and nonlocal resistances. Energy spectroscopy reveals a reentrant behavior of the transport coefficients around the Thouless energy. {copyright} {ital 1996 The American Physical Society.}

  17. Cross-Lagged Relations between Task Motivation and Performance in Arithmetic and Literacy in Kindergarten

    ERIC Educational Resources Information Center

    Viljaranta, Jaana; Lerkkanen, Marja-Kristiina; Poikkeus, Anna-Maija; Aunola, Kaisa; Nurmi, Jari-Erik

    2009-01-01

    To examine the cross-lagged relationships between children's task motivation in mathematics and literacy, and their related performance, 139 children aged 5-6 years were examined twice during their kindergarten year. The results showed that only math-related task motivation and arithmetic performance showed cross-lagged relationship: the higher…

  18. Stationary Source Related Documents for State and Local Transportation

    EPA Pesticide Factsheets

    State and Local Transporation Resources is an EPA/OTAQ web page for state and local air quality regulators and transportation planners that offers guidance on how to reduce air pollution from cars, diesel trucks, city and school buses

  19. Measurement of Collisional Cross-Field Heat Transport in a Nonneutral Plasma.

    NASA Astrophysics Data System (ADS)

    Hollmann, E. M.; Anderegg, F.; Driscoll, C. F.

    1998-11-01

    Cross-magnetic-field heat transport has been measured for a steady-state Mg^+ ion plasma confined in a Penning-Malmberg trap. The measured thermal diffusivity is up to 200 times larger than the classical value, but agrees well with long-range collisional theory.(D.H.E. Dubin and T.M. O'Neil, Phys. Rev. Lett. 78), 3868 (1997). This measurement uses two lasers: a strong (1 mW) beam to initially create localized ion heating (or cooling); and a weak (<=0.1 mW) beam to obtain the temperature T as the heat pulse spreads. The local thermal diffusivity \\chi is calculated from the measured T (r,t). The classical theory of heat conductivity describes collisions with impact parameters less than a cyclotron radius, i.e. ρ < r_c; in contrast, the enhanced heat transport arises from long-range collisions with impact parameter rc < ρ < λ_D. The thermal diffusivity has been measured over temperature and density ranges of 5 × 10-4 < T < 5 eV and 10^6 < n < 1.3 × 10^8 cm-3, at fields 1 < B < 4;Tesla. The measured diffusivity shows no variation with n or B, and agrees quantitatively with the long-range collisional prediction of \\chi_raisebox-.8ex lr ∝ T-1/2; but disagrees strongly with the classical prediction of \\chi_raisebox-.6ex c ∝ nB-2 T-1/2.

  20. Cross-shelf transport into nearshore waters due to shoaling internal tides in San Pedro Bay, CA

    USGS Publications Warehouse

    Noble, M.; Jones, B.; Hamilton, P.; Xu, Jie; Robertson, G.; Rosenfeld, L.; Largier, J.

    2009-01-01

    In the summer of 2001, a coastal ocean measurement program in the southeastern portion of San Pedro Bay, CA, was designed and carried out. One aim of the program was to determine the strength and effectiveness of local cross-shelf transport processes. A particular objective was to assess the ability of semidiurnal internal tidal currents to move suspended material a net distance across the shelf. Hence, a dense array of moorings was deployed across the shelf to monitor the transport patterns associated with fluctuations in currents, temperature and salinity. An associated hydrographic program periodically monitored synoptic changes in the spatial patterns of temperature, salinity, nutrients and bacteria. This set of measurements show that a series of energetic internal tides can, but do not always, transport subthermocline water, dissolved and suspended material from the middle of the shelf into the surfzone. Effective cross-shelf transport occurs only when (1) internal tides at the shelf break are strong and (2) subtidal currents flow strongly downcoast. The subtidal downcoast flow causes isotherms to tilt upward toward the coast, which allows energetic, nonlinear internal tidal currents to carry subthermocline waters into the surfzone. During these events, which may last for several days, the transported water remains in the surfzone until the internal tidal current pulses and/or the downcoast subtidal currents disappear. This nonlinear internal tide cross-shelf transport process was capable of carrying water and the associated suspended or dissolved material from the mid-shelf into the surfzone, but there were no observation of transport from the shelf break into the surfzone. Dissolved nutrients and suspended particulates (such as phytoplankton) transported from the mid-shelf into the nearshore region by nonlinear internal tides may contribute to nearshore algal blooms, including harmful algal blooms that occur off local beaches.

  1. Driver's behavioural changes with new intelligent transport system interventions at railway level crossings--A driving simulator study.

    PubMed

    Larue, Grégoire S; Kim, Inhi; Rakotonirainy, Andry; Haworth, Narelle L; Ferreira, Luis

    2015-08-01

    Improving safety at railway level crossings is an important issue for the Australian transport system. Governments, the rail industry and road organisations have tried a variety of countermeasures for many years to improve railway level crossing safety. New types of intelligent transport system (ITS) interventions are now emerging due to the availability and the affordability of technology. These interventions target both actively and passively protected railway level crossings and attempt to address drivers' errors at railway crossings, which are mainly a failure to detect the crossing or the train and misjudgement of the train approach speed and distance. This study aims to assess the effectiveness of three emerging ITS that the rail industry considers implementing in Australia: a visual in-vehicle ITS, an audio in-vehicle ITS, as well as an on-road flashing beacons intervention. The evaluation was conducted on an advanced driving simulator with 20 participants per trialled technology, each participant driving once without any technology and once with one of the ITS interventions. Every participant drove through a range of active and passive crossings with and without trains approaching. Their speed approach of the crossing, head movements and stopping compliance were measured. Results showed that driver behaviour was changed with the three ITS interventions at passive crossings, while limited effects were found at active crossings, even with reduced visibility. The on-road intervention trialled was unsuccessful in improving driver behaviour; the audio and visual ITS improved driver behaviour when a train was approaching. A trend toward worsening driver behaviour with the visual ITS was observed when no trains were approaching. This trend was not observed for the audio ITS intervention, which appears to be the ITS intervention with the highest potential for improving safety at passive crossings.

  2. Cross-species comparison of genes related to nutrient sensing mechanisms expressed along the intestine.

    PubMed

    van der Wielen, Nikkie; van Avesaat, Mark; de Wit, Nicole J W; Vogels, Jack T W E; Troost, Freddy; Masclee, Ad; Koopmans, Sietse-Jan; van der Meulen, Jan; Boekschoten, Mark V; Müller, Michael; Hendriks, Henk F J; Witkamp, Renger F; Meijerink, Jocelijn

    2014-01-01

    Intestinal chemosensory receptors and transporters are able to detect food-derived molecules and are involved in the modulation of gut hormone release. Gut hormones play an important role in the regulation of food intake and the control of gastrointestinal functioning. This mechanism is often referred to as "nutrient sensing". Knowledge of the distribution of chemosensors along the intestinal tract is important to gain insight in nutrient detection and sensing, both pivotal processes for the regulation of food intake. However, most knowledge is derived from rodents, whereas studies in man and pig are limited, and cross-species comparisons are lacking. To characterize and compare intestinal expression patterns of genes related to nutrient sensing in mice, pigs and humans. Mucosal biopsy samples taken at six locations in human intestine (n = 40) were analyzed by qPCR. Intestinal scrapings from 14 locations in pigs (n = 6) and from 10 locations in mice (n = 4) were analyzed by qPCR and microarray, respectively. The gene expression of glucagon, cholecystokinin, peptide YY, glucagon-like peptide-1 receptor, taste receptor T1R3, sodium/glucose cotransporter, peptide transporter-1, GPR120, taste receptor T1R1, GPR119 and GPR93 was investigated. Partial least squares (PLS) modeling was used to compare the intestinal expression pattern between the three species. The studied genes were found to display specific expression patterns along the intestinal tract. PLS analysis showed a high similarity between human, pig and mouse in the expression of genes related to nutrient sensing in the distal ileum, and between human and pig in the colon. The gene expression pattern was most deviating between the species in the proximal intestine. Our results give new insights in interspecies similarities and provide new leads for translational research and models aiming to modulate food intake processes in man.

  3. High-field electron transport in GaN under crossed electric and magnetic fields

    NASA Astrophysics Data System (ADS)

    Kochelap, V. A.; Korotyeyev, V. V.; Syngayivska, G. I.; Varani, L.

    2015-10-01

    High-field electron transport studied in crossed electric and magnetic fields in bulk GaN with doping of 1016 cm-3, compensation around 90% at the low lattice temperature (30 K). It was found the range of the magnetic and electric fields where the non-equilibrium electron distribution function has a complicated topological structure in the momentum space with a tendency to the formation of the inversion population. Field dependences of dissipative and Hall components of the drift velocity were calculated for the samples with short- and open- circuited Hall contacts in wide ranges of applied electric (0 — 20 kV/cm) and magnetic (1 — 10 T) fields. For former sample, field dependences of dissipative and Hall components of the drift velocity have a non-monotonic behavior. The dissipative component has the inflection point which corresponds to the maximum point of the Hall component. For latter sample, the drift velocity demonstrate a usual sub-linear growth without any critical points. We found that GaN samples with controlled resistance of the Hall circuit can be utilized as a electronic high-power switch.

  4. Sediment transport data and related information for selected coarse-bed streams and rivers in Idaho

    Treesearch

    John G. King; William W. Emmett; Peter J. Whiting; Robert P. Kenworthy; Jeffrey J. Barry

    2004-01-01

    This report and associated web site files provide sediment transport and related data for coarse-bed streams and rivers to potential users. Information on bedload and suspended sediment transport, streamflow, channel geometry, channel bed material, floodplain material, and large particle transport is provided for 33 study reaches in Idaho that represent a wide range of...

  5. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... container or conveyance Limit on total sum of transport indices in a single freight container or aboard a... of criticality safety indices in a single freight container or aboard a conveyance Not under... 49 Transportation 2 2013-10-01 2013-10-01 false Requirements relating to transport indices and...

  6. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... container or conveyance Limit on total sum of transport indices in a single freight container or aboard a... of criticality safety indices in a single freight container or aboard a conveyance Not under... 49 Transportation 2 2010-10-01 2010-10-01 false Requirements relating to transport indices and...

  7. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... container or conveyance Limit on total sum of transport indices in a single freight container or aboard a... of criticality safety indices in a single freight container or aboard a conveyance Not under... 49 Transportation 2 2011-10-01 2011-10-01 false Requirements relating to transport indices and...

  8. Matrix association effects on hydrodynamic sorting and degradation of terrestrial organic matter during cross-shelf transport in the Laptev and East Siberian shelf seas

    NASA Astrophysics Data System (ADS)

    Tesi, Tommaso; Semiletov, Igor; Dudarev, Oleg; Andersson, August; Gustafsson, Örjan

    2016-03-01

    This study seeks an improved understanding of how matrix association affects the redistribution and degradation of terrigenous organic carbon (TerrOC) during cross-shelf transport in the Siberian margin. Sediments were collected at increasing distance from two river outlets (Lena and Kolyma Rivers) and one coastal region affected by erosion. Samples were fractionated according to density, size, and settling velocity. The chemical composition in each fraction was characterized using elemental analyses and terrigenous biomarkers. In addition, a dual-carbon-isotope mixing model (δ13C and Δ14C) was used to quantify the relative TerrOC contributions from active layer (Topsoil) and Pleistocene Ice Complex Deposits (ICD). Results indicate that physical properties of particles exert first-order control on the redistribution of different TerrOC pools. Because of its coarse nature, plant debris is hydraulically retained in the coastal region. With increasing distance from the coast, the OC is mainly associated with fine/ultrafine mineral particles. Furthermore, biomarkers indicate that the selective transport of fine-grained sediment results in mobilizing high-molecular weight (HMW) lipid-rich, diagenetically altered TerrOC while lignin-rich, less degraded TerrOC is retained near the coast. The loading (µg/m2) of lignin and HMW wax lipids on the fine/ultrafine fraction drastically decreases with increasing distance from the coast (98% and 90%, respectively), which indicates extensive degradation during cross-shelf transport. Topsoil-C degrades more readily (90 ± 3.5%) compared to the ICD-C (60 ± 11%) during transport. Altogether, our results indicate that TerrOC is highly reactive and its accelerated remobilization from thawing permafrost followed by cross-shelf transport will likely represent a positive feedback to climate warming.

  9. \\A Gravity-Related Transport in Reactive Off-Axis Sputtering Deposition

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Su, C.-H.; Lehozeky, S. L.

    2000-01-01

    An experiment was designed to investigate the transport characterization of reactive off- axis sputtering deposition. Three transport regions were observed when the growth pressures vary from 5 mtorr to 150 mtorr. A new gravity-related phenomenon was revealed in film growth at relatively high growth pressures. This effect is related to the collision process or thermalization of transport species. This study also suggests a design for the substrate holder orientation in the off-axis sputtering system.

  10. \\A Gravity-Related Transport in Reactive Off-Axis Sputtering Deposition

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Su, C.-H.; Lehozeky, S. L.

    2000-01-01

    An experiment was designed to investigate the transport characterization of reactive off- axis sputtering deposition. Three transport regions were observed when the growth pressures vary from 5 mtorr to 150 mtorr. A new gravity-related phenomenon was revealed in film growth at relatively high growth pressures. This effect is related to the collision process or thermalization of transport species. This study also suggests a design for the substrate holder orientation in the off-axis sputtering system.

  11. Glucose transporters in sex steroid hormone related cancer.

    PubMed

    Nualart, Francisco; Los Angeles García, Maríade; Medina, Rodolfo A; Owen, Gareth I

    2009-10-01

    Cancer cells, as with most mammalian cells, depend on a continuous supply of glucose; not only as a precursor of glycoproteins, triglycerides and glycogen, but also as an important source of energy. This review concentrates on GLUT transporter expression in both normal and cancerous classical sex-steroid hormone tissues (i.e. breast, uterus, ovary, testis and prostate, among others). Given the importance of estrogen, progesterone and androgens in carcinogenesis, as well as in survival and propagation of these cancers, this review also highlights the current literature on hormone regulation of glucose transporters and on the role of hypoxia in their expression. Given the recent explosion of information on the newer GLUT6-12 family members, a brief overview on their function and general expression has been included. Finally, an insight into the use of glucose transporters as markers of cancer progression and clinical outcome is also discussed.

  12. Transportation

    NASA Technical Reports Server (NTRS)

    Vontiesenhausen, G.

    1986-01-01

    A summary of tether transportation is given. Four steps were used over a period of time. First, theoretical engineering feasibility and technology requirements were determined. Then the survivors of that effort went into step two in the analysis of promising candidates. Those survivors went into the third phase which is engineering design and cost benefits. Survivors entered into the demonstration mission definition phase. Transportation studies have covered two kinds of deployments. First, steady state deployment was studied. Like the TSS, it's nearly vertical. It takes a long time to deploy and involves relatively high tether tension. Secondly, dynamic deployment was studied. Deployment started in an almost horizontal direction under a very shallow angle which allows a high deployment rate under very low tension. Momentum transfer here occurs by libration. Specific payloads were used to study tethered transportation benefits. Four transportation concepts were studied with regard to cost benefits. A tethered orbiter deboost from the space station, an OTV boost up from the Space Station, a science platform on a tether with a possible micro-g lab moving in between platform and station, and a tethered boost of payloads fromthe orbiter are the four concepts. These benefits are examined in detail.

  13. Monsoon-related transport processes: HCFC-22 as a tracer for East-Asian pollution transport

    NASA Astrophysics Data System (ADS)

    Stiller, Gabriele; von Clarmann, Thomas; Kellmann, Sylvia; Chirkov, Maksym; Vogel, Bärbel; Müller, Rolf

    2016-04-01

    East-Asian pollution from Southern China or India was shown to be uplifted effectively by the Asian monsoon system to levels just below the tropopause. HCFC-22 nowadays has it strongest source region within East Asia. Due to its long lifetime in the troposphere, it is a very well suited transport tracer. We compare observations from MIPAS/Envisat of HCFC-22 with results from pollution transport modelling by the Lagrangian chemistry-transport model CLaMS. We find that East Asian pollution (and HCFC-22) is uplifted into the Asian monsoon anticyclone at the Eastern flank of the monsoon system. However, we do not find any indication of a significant transport through the tropopause of the Asian monsoon anticyclone into the stratosphere. In contrast, HCFC-22 is transported southwards into the tropics during the end phase and the break-down of the Asian monsoon anticyclone and distributed zonally in the tropics. By this a maximum layer of HCFC-22 just below the tropical tropopause is formed. Further transport into the stratosphere happens mainly by uplift within the upwelling branch of the Brewer-Dobson circulation.

  14. Transport-related phenomena for clusters of drops

    NASA Technical Reports Server (NTRS)

    Bellan, J.; Harstad, K.

    1989-01-01

    Calculations for n-decane drops evaporating in a spherical cluster surrounded by unvitiated ambient air at atmospheric pressure were performed using two previously proposed cluster models. Both cluster models predict that turbulent transport effects are more important in the case of small clusters. This is due to the smaller volume to surface ratio and thus to the greater transport of hot unvitiated gas to the drops in order to promote evaporation. The results obtained are compared with those of two turbulent models for each one of the 'trapping factors' and similarity models.

  15. Object relations and real life relationships: a cross method assessment.

    PubMed

    Handelzalts, Jonathan E; Fisher, Shimrit; Naot, Rachel

    2014-04-01

    This study examines the relationship between the psychoanalytic concept of object relations and real life behavior of being in an intimate relationship among heterosexual women. In a multi-method approach we used two different measures; the self-report Bell Object Relations and Reality Testing Inventory (BORRTI; Bell, Billington & Becker, 1986) and the performance based Thematic Apperception Test (TAT) Social Cognition & Object Relations Scale- Global Rating Method SCORS-G (Westen, 1995) to measure the object relations of 60 women. The Alienation subscale of the BORRTI and understanding of social causality subscale of the SCORS-G explained 34.8% of variance of the intimate relationship variable. Thus, women involved in a romantic relationship reported lower rates of alienation on the BORRTI and produced TAT narratives that were more adaptive with regard to understanding of social causality as measured by the SCORS-G than those not currently in a relationship. Results are discussed with reference to the relationship between object relations and real life measures of healthy individuals and in light of the need for a multi-method approach of assessment.

  16. Sudden Clearing of Estuarine Waters upon Crossing the Threshold from Transport to Supply Regulation of Sediment Transport as an Erodible Sediment Pool is Depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, D.H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991-1998 to 1999-2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing. ?? 2011 Coastal and Estuarine Research Federation (outside the USA).

  17. Role of mesoscale eddies in cross-frontal transport of carbon and nutrients in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Dufour, Carolina O.; Griffies, Stephen M.; Palter, Jaime B.; de Souza, Gregory F.; Sarmiento, Jorge L.; Galbraith, Eric D.

    2014-05-01

    The Southern Ocean plays a key role in oceanic carbon storage and global nutrient distributions. Here, carbon and nutrients are transferred into the ocean interior by the formation and subduction of mode and intermediate water masses. Much of the subducted carbon and nutrients in these water masses derive from waters upwelled at the Antarctic Divergence that must cross the numerous fronts of the Antarctic Circumpolar Current (ACC) to reach the sites of water mass formation. These energetic frontal jets are natural barriers to tracer exchange but allow some crossings via specific mechanisms. While northward Ekman transport has been elucidated as the major mechanism for cross-frontal transport of tracers at intra-annual scale, little is known about the role of mesoscale eddies in mediating tracer exchange across fronts. This study aims to address the role of mesoscale eddies in cross-frontal transport of carbon and nutrients in the Southern Ocean while (i) quantifying the net transport of tracers across the various fronts of the ACC, (ii) describing the hot spots of tracer exchange, (iii) investigating the time-scales of this exchange and its response to climate change. To this purpose, we use a 1/10° configuration of the GFDL climate model (CM2.6) coupled to a simplified version of the biogeochemistry model BLING where dissolved inorganic carbon (DIC), phosphate and oxygen are simulated. The model is started from observations with DIC corrected to preindustrial conditions, and run for a 120 year spin-up from which two 80 year simulations are performed: a preindustrial control with constant radiative forcing and a sensitivity with a 1%/year increase in atmospheric CO2 concentration. We focus our analyses on the last 20 years of both simulations sampled at monthly frequency. Online tendency terms are used to compute the total transport of DIC, phosphate and oxygen across the main fronts of the ACC, and to single out the mesoscale eddy component of the transport. The

  18. Policies related to active transport to and from school: a multisite case study.

    PubMed

    Eyler, Amy A; Brownson, Ross C; Doescher, Mark P; Evenson, Kelly R; Fesperman, Carrie E; Litt, Jill S; Pluto, Delores; Steinman, Lesley E; Terpstra, Jennifer L; Troped, Philip J; Schmid, Thomas L

    2008-12-01

    Active transportation to and from school (ATS) is a viable strategy to help increase physical activity among youth. ATS can be challenging because initiatives require transdisciplinary collaboration, are influenced by the built environment and are affected by numerous policies. The purpose of this study is to identify policies and factors that influence ATS initiatives. Nine elementary schools in seven states participated in this case study. Sixty-nine stakeholders were interviewed. The interviews were transcribed, coded and analyzed using a master thematic codebook. This study identified two distinct aspects of policies: 'influential factors' which are factors that might impact policies related to ATS and 'policy actions' which are policies reported by people involved in ATS initiatives that directly affected their success. Influential factors included sidewalks, crosswalks/crossing guards, funding, personal safety concerns, advocacy group involvement and others. Policy actions included policies on school speed zone, drop-off, no-transport zones, school siting, school start/dismissal time and school choice. Despite the diversity of the schools studied, similarities included influence of built environment, safety concerns, funding and transdisciplinary collaboration. Stakeholders need to work together to stimulate action and ensure successful initiatives. Influential factors appear to be important to this process.

  19. French and American Cross-Cultural Military Education and Relations: One Naval Officer’s Perspective

    DTIC Science & Technology

    1997-03-01

    determine whether cross- cultural education would have changed the outcome of history. However, a historical perspective may alert the reader to a ...from the perspective of the author of this paper. First, both schools possess the progressive potential to incorporate a formal cross- cultural ...AU/ACSC/0605C/97-03 FRENCH AND AMERICAN CROSS- CULTURAL MILITARY EDUCATION AND RELATIONS: ONE NAVAL OFFICER’S PERSPECTIVE A Research Paper

  20. In-Situ Observations of Cross-Shore Sediment Transport in Response to Waves Along the Inner-Continental Shelf Offshore from Fire Island, NY

    NASA Astrophysics Data System (ADS)

    Harrison, S. R.; Traykovski, P.; Warner, J. C.; List, J. H.

    2016-02-01

    Fire Island is a 50 km long barrier island along the southern shore of Long Island, NY (USA) that protects a populated mainland from large waves and storms. Previous sediment budget analyses have identified cross-shore sediment flux from the inner-continental shelf as the likely sand source [O(200,000 m3/yr)] required to account for accretion along the central segment of the island. To investigate the mechanisms driving cross-shore sediment flux, quad-pod instrument frames were deployed from January to April 2014 along the inner-shelf offshore of Fire Island at 12-15 m water depth equipped with acoustic sensors to concurrently measure surface waves, hydrodynamic flows, near-bed wave orbital velocity and turbulence, vertical profiles of near-bed suspended sediment, and bedform morphology and migration. The measurements were made at this location to quantify cross-shore sediment flux in response to wave forcing at depths where both wave skewness and wave-current interactions should significantly contribute to cross-shore sediment transport.Bedform migration and geometry were computed from rotary sonar images and consisted of orbital-scale ripples with wavelengths between 0.3 to 1.2 m, and oriented ±40° from directly onshore. Ripple heights ranged from 0.04 to 0.19 m with a slight onshore-directed asymmetry. Ripple migration occurred in response to wave events and was used as a proxy to estimate transport at the bed. Migration rates were related to the cube of near-bed wave-orbital velocity, in the peak direction of wave propagation. The ripple geometry and migration enabled estimation of the net cross-shore bedload sediment volume flux, which was directed onshore O(1 m3/yr per m alongshore) at the quad-pods during the deployment. These rates will be compared to migration at other locations to determine relative migration scales.Cross-shore suspended sediment flux was computed from profiles of velocity and acoustic-backscatter estimates of suspended

  1. Relating Fiber Crossing in HARDI to Intellectual Function

    DTIC Science & Technology

    2010-02-01

    sensitized) MR images were acquired from 293 right-handed healthy young adult twins and their siblings (23.9 ± 1.9 years old; 112 monozygotic subjects...linear random effects regression analysis to account for familial relations in the twin samples, voxelwise FA and TQOd maps were each regressed against

  2. Gate-modulated transport properties and mechanism for nanowire cross junction based on SnO2 semiconductor

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Tong, Yanhong; Wang, Guorui; Tang, Qingxin; Liu, Yichun

    2015-12-01

    The transport properties and mechanism of the three-terminal field-effect nanowire cross junction have been systematically investigated. An interesting phenomenon, such as applied voltage bias on nanowire cross junction makes the ON/OFF current ratio of the transistor improved by over 2 orders of magnitude, has been observed. Different from the two-terminal nanowire cross junctions, the cross junction induced potential barrier in three-terminal counterparts is found to be capable to prevent the current of the top semiconductor nanowire from injecting into the bottom nanowire at off state, while to make the current of the top semiconductor nanowire contribute to the current of the bottom nanowire at on state, resulting in the current switch between on state and off state by the gate voltage modulation.

  3. The role of suspension events in cross-shore and longshore suspended sediment transport in the surf zone

    USGS Publications Warehouse

    Jaffe, Bruce E.

    2015-01-01

    Suspension of sand in the surf zone is intermittent. Especially striking in a time series of concentration are periods of intense suspension, suspension events, when the water column suspended sediment concentration is an order of magnitude greater than the mean concentration. The prevalence, timing, and contribution of suspension events to cross-shore and longshore suspended sediment transport are explored using field data collected in the inner half of the surf zone during a large storm at Duck, NC. Suspension events are defined as periods when the concentration is above a threshold. Events tended to occur during onshore flow under the wave crest, resulting in an onshore contribution to the suspended sediment transport. Even though large events occurred less than 10 percent of the total time, at some locations onshore transport associated with suspension events was greater than mean-current driven offshore-directed transport during non-event periods, causing the net suspended sediment transport to be onshore. Events and fluctuations in longshore velocity were not correlated. However, events did increase the longshore suspended sediment transport by approximately the amount they increase the mean concentration, which can be up to 35%. Because of the lack of correlation, the longshore suspended sediment transport can be modeled without considering the details of the intensity and time of events as the vertical integration of the product of the time-averaged longshore velocity and an event-augmented time-averaged concentration. However, to accurately model cross-shore suspended sediment transport, the timing and intensity of suspension events must be reproduced.

  4. Correcting Evaluation Bias of Relational Classifiers with Network Cross Validation

    DTIC Science & Technology

    2010-01-01

    Computer Sciences (with a minor in Mathematical Statistics ) at the University of Wisconsin-Madison in 2001. Broadly speaking, Tina’s research interests...These methods specifically exploit the statistical dependencies among instances in order to improve classification accuracy. However, there has been...the complex link structure and attribute dependencies in relational data violate the assumptions of many conventional statistical tests and make it

  5. Testing and parameterizing a conceptual solute transport model in saturated fractured tuff using sorbing and nonsorbing tracers in cross-hole tracer tests.

    PubMed

    Reimus, Paul W; Haga, Marc J; Adams, Andrew I; Callahan, Timothy J; Turin, H J; Counce, Dale A

    2003-01-01

    Two cross-hole tracer tests involving the simultaneous injection of two nonsorbing solute tracers with different diffusion coefficients (bromide and pentafluorobenzoate) and one weakly sorbing solute tracer (lithium ion) were conducted in two different intervals at the C-wells complex near the site of a potential high-level nuclear waste repository at Yucca Mountain, NV. The tests were conducted to (1) test a conceptual radionuclide transport model for saturated, fractured tuffs near Yucca Mountain and (2) obtain transport parameter estimates for predictive modeling of radionuclide transport. The differences between the responses of the two nonsorbing tracers and the sorbing tracer (when normalized to injection masses) were consistent with a dual-porosity transport system in which matrix diffusion was occurring. The concentration attenuation of the sorbing tracer relative to the nonsorbing tracers suggested that diffusion occurred primarily into matrix pores, not simply into stagnant water within the fractures. The K(d) values deduced from the lithium responses were generally larger than K(d) values measured in laboratory batch sorption tests using crushed C-wells cores. This result supports the use of laboratory-derived K(d) values for predicting sorbing species transport at the site, as the laboratory K(d) values would result in underprediction of sorption and hence conservative transport predictions. The tracer tests also provided estimates of effective flow porosity and longitudinal dispersivity at the site. The tests clearly demonstrated the advantages of using multiple tracers of different physical and chemical characteristics to distinguish between alternative conceptual transport models and to obtain transport parameter estimates that are better constrained than can be obtained using only a single tracer or using multiple nonsorbing tracers without a sorbing tracer.

  6. Horizontal spatial correlation of hydraulic and reactive transport parameters as related to hierarchical sedimentary architecture at the Borden research site

    NASA Astrophysics Data System (ADS)

    Ritzi, R. W.; Huang, L.; Ramanathan, R.; Allen-King, R. M.

    2013-04-01

    Highly resolved data from the Borden research site provide a unique opportunity to study the horizontal spatial bivariate correlation of hydraulic and reactive attributes affecting subsurface transport. The data also allow quantitatively relating this correlation to the hierarchical sedimentary architecture of the aquifer. The data include collocated samples of log permeability, Y, the log of the perchloroethene sorption distribution coefficient, Ξ, and lithologic unit type. The horizontal Y and Ξ autosemivariograms and the Ξ-Y cross-semivariogram have the same underlying correlation structure (shape and range in the rise to a sill). The common structure is not due to Ξ-Y point correlation or in-unit spatial correlation. The common structure is defined by how the proportion of lag transitions crossing different unit types (i.e., the cross-transition probability structure) increases with increasing lag distance. The common underlying cross-transition structure contains two substructures with different correlation ranges corresponding to two scales of unit types within the sedimentary architecture. For each substructure, a large standard deviation in the length of units relative to the mean length gives rise to an exponential-like shape and the proportions and mean length of units define the ranges. The horizontal Ξ-Y spatial cross correlation is primarily defined by the larger-scale substructure and the differences in mean Ξ and Y between larger-scale unit types.

  7. 47 CFR 19.735-102 - Cross-reference to ethics and other conduct related regulations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Cross-reference to ethics and other conduct related regulations. 19.735-102 Section 19.735-102 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMPLOYEE RESPONSIBILITIES AND CONDUCT General Provisions § 19.735-102 Cross-reference to...

  8. Cell protein cross-linking by erbstatin and related compounds | Center for Cancer Research

    Cancer.gov

    The scheme depicts a possible mechanism of cross-linking by erbstatin and related analogues. A mechanism of action is proposed which involves initial oxidation to reactive quinone intermediates that subsequently cross-link protein nucleophiles via multiple 1,4-Michael-type additions. Similar alkylation of protein by protein-tyrosine kinase inhibitors, such as herbimycin A, has been invoked.

  9. Peer and Cross-Age Tutoring and Related Topics: An Annotated Bibliography. Theoretical Paper No. 53.

    ERIC Educational Resources Information Center

    Wilkes, Roberta

    This annotated bibliography is an effort to provide educators and researchers with a comprehensive listing of current resources, information, and research concerning peer and cross age academic tutoring by students, together with a selection of references on related topics of cross age interactions, tutoring in general, and the use of…

  10. Cyanide removal from industrial wastewater by cross-flow nanofiltration: transport modeling and economic evaluation.

    PubMed

    Pal, Parimal; Bhakta, Pamela; Kumar, Ramesh

    2014-08-01

    A modeling and simulation study, along with an economic analysis, was carried out for the separation of cyanide from industrial wastewater using a flat sheet cross-flow nanofiltration membrane module. With the addition of a pre-microfiltration step, nanofiltration was carried out using real coke wastewater under different operating conditions. Under the optimum operating pressure of 13 bars and a pH of 10.0, a rate of more than 95% separation of cyanide was achieved. That model predictions agreed very well with the experimental findings, as is evident in the Willmott d-index value (> 0.95) and relative error (< 0.1). Studies were carried out with industrial wastewater instead of a synthetic solution, and an economic analysis was also done, considering the capacity of a running coking plant. The findings are likely to be very useful in the scale-up and design of industrial plants for the treatment of cyanide-bearing wastewater.

  11. Crossed contributions to electron and heavy-particle transport fluxes for magnetized plasmas in the continuum regime

    NASA Astrophysics Data System (ADS)

    Scoggins, James B.; Knisely, Carleton P.; Magin, Thierry E.

    2016-11-01

    We propose a unified fluid model for multicomponent plasmas in thermal nonequilibrium accounting for the influence of the electromagnetic field. In a previous work, this model was derived from kinetic theory based on a generalized Chapman-Enskog perturbative solution of the Boltzmann equation, scaled using the ratio of electron to heavy-particle masses. Anisotropic transport properties were derived in terms of bracket integrals. In this work, explicit expressions for asymptotic solutions of the transport properties are derived using a spectral Galerkin projection supplied with Laguerre-Sonine polynomial basis functions, and we analyze the crossed contributions to electron and heavy particle mass and energy fluxes, known as the Kolesnikov effect.

  12. Cross sectional analysis of the association between mode of school transportation and physical fitness in children and adolescents.

    PubMed

    Ostergaard, Lars; Kolle, Elin; Steene-Johannessen, Jostein; Anderssen, Sigmund A; Andersen, Lars Bo

    2013-07-17

    To investigate the associations between body composition, cardiorespiratory and muscular fitness in relation to travel mode to school in children and adolescents. Children and adolescents from 40 elementary schools and 23 high schools representing all regions in Norway were invited to participate in the study. Anthropometry, cardiorespiratory and muscular fitness were tested at the school location. Questionnaires were used in order to register mode of transport to school, age, gender and levels of leisure time physical activity. A total of 1694 (i.e. 60% of all invited participants) children and adolescents at a mean age of 9.6 and 15.6 respectively (SD = 0.4 for both groups) were analyzed for associations with physical fitness variables. Males cycling to school had lower sum of skin folds than adolescents walking to school. Higher cardiorespiratory fitness in adolescents and male cyclists compared to walkers and passive commuters were observed. Among children, cycling and walking to school, higher isometric muscle endurance in the back extensors compared to passive commuters was observed. Based on this national representative cross-sectional examination of randomly selected children and adolescents there is evidence that active commuting, especially cycling, is associated with a favourable body composition and better cardiorespiratory and muscular fitness as compared to passive commuting.

  13. Factors related to venous ulceration: a cross-sectional study.

    PubMed

    Vlajinac, Hristina; Marinkovic, Jelena; Maksimovic, Milos; Radak, Djordje

    2014-10-01

    The aim of the study was to determine the factors related to venous ulceration. Patients with venous ulceration (278 patients) were compared with 1401 patients in other categories of clinical classification of venous disease (clinical, etiologic, anatomic, and pathophysiological [CEAP]). Demographic, anthropometric, and clinical data were collected. Univariate and multivariate logistic regression analyses were used. According to multivariate analyses, risk factors for venous ulceration were age, male sex, personal history of superficial and deep venous thrombosis, diabetes, high blood pressure, skeletal or joint disease in the legs and emphysema or chronic obstructive pulmonary disease, higher body mass index and physical inactivity, parental history of ankle ulcer as well as reflux in deep and perforator veins, deep obstruction, and combination of reflux and obstruction. It seems reasonable to pay special attention to patients in whom the postulated risk factors for venous ulceration are present.

  14. In Vitro-In Vivo Extrapolation Scaling Factors for Intestinal P-Glycoprotein and Breast Cancer Resistance Protein: Part I: A Cross-Laboratory Comparison of Transporter-Protein Abundances and Relative Expression Factors in Human Intestine and Caco-2 Cells.

    PubMed

    Harwood, Matthew D; Achour, Brahim; Neuhoff, Sibylle; Russell, Matthew R; Carlson, Gordon; Warhurst, Geoffrey

    2016-03-01

    Over the last 5 years the quantification of transporter-protein absolute abundances has dramatically increased in parallel to the expanded use of in vitro-in vivo extrapolation (IVIVE) and physiologically based pharmacokinetics (PBPK)-linked models, for decision-making in pharmaceutical company drug development pipelines and regulatory submissions. Although several research groups have developed laboratory-specific proteomic workflows, it is unclear if the large range of reported variability is founded on true interindividual variability or experimental variability resulting from sample preparation or the proteomic methodology used. To assess the potential for methodological bias on end-point abundance quantification, two independent laboratories, the University of Manchester (UoM) and Bertin Pharma (BPh), employing different proteomic workflows, quantified the absolute abundances of Na/K-ATPase, P-gp, and breast cancer resistance protein (BCRP) in the same set of biologic samples from human intestinal and Caco-2 cell membranes. Across all samples, P-gp abundances were significantly correlated (P = 0.04, Rs = 0.72) with a 2.4-fold higher abundance (P = 0.001) generated at UoM compared with BPh. There was a systematically higher BCRP abundance in Caco-2 cell samples quantified by BPh compared with UoM, but not in human intestinal samples. Consequently, a similar intestinal relative expression factor (REF), derived from distal jejunum and Caco-2 monolayer samples, between laboratories was found for P-gp. However, a 2-fold higher intestinal REF was generated by UoM (2.22) versus BPh (1.11). We demonstrate that differences in absolute protein abundance are evident between laboratories and they probably result from laboratory-specific methodologies relating to peptide choice.

  15. Aging of marine organic matter during cross-shelf lateral transport in the Benguela upwelling system revealed by compound-specific radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Mollenhauer, Gesine; Inthorn, Maik; Vogt, Thomas; Zabel, Matthias; Sinninghe Damsté, Jaap S.; Eglinton, Timothy I.

    2007-09-01

    Organic matter accumulation and burial on the Namibian shelf and upper slope are spatially heterogeneous and strongly controlled by lateral transport in subsurface nepheloid layers. Much of the material deposited in depo-centers on the slope ultimately derives from the shelf. Supply of organic matter from the shelf involves selective transport of organic matter. We studied these selective transport processes by analyzing the radiocarbon content of co-occurring sediment fractions. Here we present radiocarbon data for total organic carbon as well as three tracers of surface ocean productivity (phytoplankton-derived alkenones, membrane lipids of pelagic crenarchaeota (crenarchaeol), and calcareous microfossils of planktic foraminifera) in core-top and near-surface sediment samples. The samples were collected on the Namibian margin along a shelf-slope transect (85 to 1040 m) at 24°S and from the upper slope depo-center at 25.5°S. In core-top sediments, alkenone ages gradually increased from modern to 3490 radiocarbon years with distance from shore and with water depth. Crenarchaeol, while younger than alkenones, also increased in age with distance offshore. It was concluded that the observed ages were a consequence of cross-shelf transport and associated aging of organic matter. Radiocarbon ages of preserved lipid biomarkers in sediments thus at least partially depend on the relative amount of laterally supplied, pre-aged material present in a sample, highlighting the importance of nepheloid transport for the sedimentation of organic matter over the Namibian margin.

  16. Polar auxin transport in relation to long-distance transport of nutrients in the Charales.

    PubMed

    Raven, John A

    2013-01-01

    This paper examines the significance of the recent demonstration of polar auxin transport (PAT) in the green macroalga Chara (Charophyceae: Charales) and, especially, options for explaining some features of PAT in the Charales. The occurrence of PAT in the Charales shows that PAT originated in the algal ancestors of the embryophytes (liverworts, mosses, hornworts, and vascular plants), although it is not yet known if PAT occurs elsewhere in the Charophyceae or in other algae. While in the embryophytes PAT occurs in parenchymatously constructed structures which commonly also have xylem and phloem (or their bryophyte analogues) as long-distance transport processes in parallel to PAT, in Chara corallina PAT shares the pathway for long-distance transport of nutrients though the parenchymatously constructed nodal complexes and the single giant cells of the internode. The speed of auxin movement of PAT is much more rapid than that attributable to diffusion and of the same order as the rate of cytoplasmic streaming in the giant internodal cells, yet complete inhibition of streaming by the inhibitor cytochalasin H does not slow down auxin transport. Explanations for this phenomenon are sought in the operation of other mechanochemical motors, dynein-tubulin and kinesin-tubulin, as alternatives to the myosin-actin system which powers cytoplasmic streaming. Experiments in which microtubules are disrupted, for example by colchicine, could show if one of the tubulin-based motors is involved. If these motors are involved, some mechanism is needed to amplify the speeds known for the motors to explain the order of magnitude higher speeds seen for auxin transport.

  17. 29 CFR 780.908 - Relation of employee's work to specified transportation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Relation of employee's work to specified transportation... Relation of employee's work to specified transportation. In order for the exemption to apply to an employee... activities is not exempt work. The employee must be actually engaged in the described operations. The...

  18. 29 CFR 780.908 - Relation of employee's work to specified transportation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Relation of employee's work to specified transportation... Relation of employee's work to specified transportation. In order for the exemption to apply to an employee... activities is not exempt work. The employee must be actually engaged in the described operations. The...

  19. Convoys of Social Relations in Cross-National Context.

    PubMed

    Ajrouch, Kristine J; Fuller, Heather R; Akiyama, Hiroko; Antonucci, Toni C

    2017-01-19

    This study examines national variations in social networks among older adults across 4 countries in diverse regions of the world: Japan, Lebanon, Mexico, and the United States. The aim is to provide insights into universal as well as unique attributes of social networks in later life. The analyses examine convoy characteristics among adults aged 50+ in metropolitan areas of Japan (N = 557), Lebanon (N = 284), Mexico (N = 556), and the United States (N = 583). Data were collected using the hierarchical mapping technique on representative samples in each locale. Multilevel models were conducted by nation to examine whether convoy characteristics vary by age and closeness. Network size and geographic proximity were dimensions of social networks sensitive to national context. By contrast, how age and feelings of closeness varied with contact frequency and the presence of children in networks revealed universal patterns. Furthermore, feelings of closeness varied by age with regard to size and contact frequency in Lebanon, proximity in Japan, and composition in Mexico. Identifying universal and unique characteristics of social networks in later life provide a preliminary empirical basis upon which to advance a global perspective on convoys of social relations and how they inform policies that can facilitate health and well-being among middle-aged and older people around the world.

  20. Walking for transportation in Hong Kong Chinese urban elders: a cross-sectional study on what destinations matter and when.

    PubMed

    Cerin, Ester; Lee, Ka-yiu; Barnett, Anthony; Sit, Cindy H P; Cheung, Man-chin; Chan, Wai-man; Johnston, Janice M

    2013-06-20

    Walking for transport can contribute to the accrual of health-enhancing levels of physical activity in elders. Identifying destinations and environmental conditions that facilitate this type of walking has public health significance. However, most findings are limited to Western, low-density locations, while a larger proportion of the global population resides in ultra-dense Asian metropolises. We investigated relationships of within-neighborhood objectively-measured destination categories and environmental attributes with walking for transport in 484 elders from an ultra-dense metropolis (Hong Kong). We estimated relationships of diversity (number of different types) and prevalence of within-neighborhood destination categories (environmental audits of 400 m buffers surrounding residential addresses) with transport-related walking (interviewer-administered questionnaire) in 484 Chinese-speaking elders able to walk unassisted and living in 32 neighborhoods stratified by socio-economic status and transport-related walkability. We examined the moderating effects of safety and pedestrian infrastructure-related neighborhood attributes on destination-walking associations. Participants reported on average 569 and 254 min/week of overall and within-neighborhood walking for transport, respectively. The prevalence of public transit points and diversity of recreational destinations were positively related to overall walking for transport. The presence of a health clinic/service and place of worship, higher diversity in recreational destinations, and greater prevalence of non-food retails and services, food/grocery stores, and restaurants in the neighborhood were predictive of more within-neighborhood walking for transport. Neighborhood safety-related aspects moderated the relationship of overall walking for transport with the prevalence of public transit points, this being positive only in safe locations. Similar moderating effects of safety-related attributes were observed

  1. Walking for transportation in Hong Kong Chinese urban elders: a cross-sectional study on what destinations matter and when

    PubMed Central

    2013-01-01

    Background Walking for transport can contribute to the accrual of health-enhancing levels of physical activity in elders. Identifying destinations and environmental conditions that facilitate this type of walking has public health significance. However, most findings are limited to Western, low-density locations, while a larger proportion of the global population resides in ultra-dense Asian metropolises. We investigated relationships of within-neighborhood objectively-measured destination categories and environmental attributes with walking for transport in 484 elders from an ultra-dense metropolis (Hong Kong). Methods We estimated relationships of diversity (number of different types) and prevalence of within-neighborhood destination categories (environmental audits of 400 m buffers surrounding residential addresses) with transport-related walking (interviewer–administered questionnaire) in 484 Chinese-speaking elders able to walk unassisted and living in 32 neighborhoods stratified by socio-economic status and transport-related walkability. We examined the moderating effects of safety and pedestrian infrastructure-related neighborhood attributes on destination-walking associations. Results Participants reported on average 569 and 254 min/week of overall and within-neighborhood walking for transport, respectively. The prevalence of public transit points and diversity of recreational destinations were positively related to overall walking for transport. The presence of a health clinic/service and place of worship, higher diversity in recreational destinations, and greater prevalence of non-food retails and services, food/grocery stores, and restaurants in the neighborhood were predictive of more within-neighborhood walking for transport. Neighborhood safety-related aspects moderated the relationship of overall walking for transport with the prevalence of public transit points, this being positive only in safe locations. Similar moderating effects of safety-related

  2. Thermodynamic and transport properties of cryogenic propellants and related fluids

    NASA Technical Reports Server (NTRS)

    Johnson, V. J.

    1973-01-01

    Significant advances have been made in recent years in the quality and range of thermophysical data for the cryogenic propellants, pressurants, and inertants. A review of recently completed and current data compilation projects for helium, hydrogen, argon, nitrogen, oxygen, fluorine, and methane is given together with recommended references for thermodynamic and transport property data tables for these fluids. Modern techniques in the plotting of thermodynamic charts from tabular data (or from functions such as the equation of state) have greatly improved their precision and value. A list of such charts is included.

  3. Time Resolved Studies of In-Well and Cross-Well Carrier Transport in MQW Semiconductor Structures

    DTIC Science & Technology

    1992-11-24

    strained layer InGaAs/GaAs lasers. On a parallel project, intermixed quantum well samples are being characterized by SIMS 31 analysis at Charles Evans...continued to supply MQW samples for intermixing studies and single quantum well InGaAs/GaAs lasers for studies of optical switching with gain. 32 ...and cross- well carrier transport in multiple quantum well (MQW) semiconductors. Carrier emission from both multiple and single quantum well devices

  4. Evolution and persistence of cross-directional statistical dependence during finite-Péclet transport through a real porous medium

    NASA Astrophysics Data System (ADS)

    Most, Sebastian; Bijeljic, Branko; Nowak, Wolfgang

    2016-11-01

    Transport of passive, dissolved compounds in fully-saturated complex porous media frequently exhibits non-Fickian characteristics. One of the most interesting questions is to ascertain the time scales at which it is possible to describe transport as a statistically independent process. Therefore, we study the mechanisms for evolution and then the decrease of non-Fickianity as a function of increasing time. Adopting the Lagrangian perspective, we provide a nonlinear copula analysis of advective-diffusive processes by analyzing particle trajectories in a real porous media, as provided by direct numerical simulations on the three-dimensional image of Doddington sandstone. First, we analyze the memory effects between time-consecutive particle position increments and cross dependence between longitudinal and transversal particle position increments as a function of given time increments and time lags between consecutive time increments. Second, we investigate the influence of the Péclet regime on the temporal evolution of dependence. Our main findings are: (a) Cross dependence between longitudinal and transversal particle position increments is persistent over the investigated range of time increments, even though this aspect has been neglected up to date. (b) Lower Péclet numbers lead to a weaker dependence that is, however, more persistent over time than in higher-Péclet transport regimes. We confirm that non-Fickianity comes from spatial coherence associated with heterogeneities of the velocity field that introduce cross dependence and memory into the transport process. Overall, we show that memory and cross dependence are persistent in and among all directions, that the dependence is highly-nonlinear, occurs at different temporal scales, and is dependent on the Péclet number.

  5. Negative Trends in Transport-related Mortality Rates in Broiler Chickens.

    PubMed

    Vecerek, Vladimir; Voslarova, Eva; Conte, Francesca; Vecerkova, Lenka; Bedanova, Iveta

    2016-12-01

    The high incidence of deaths during transport for slaughter is associated with poor welfare and represents a considerable loss to the poultry industry. In the period from 2009 to 2014, all shipments of broiler chickens to poultry processing plants were monitored in the Czech Republic and the numbers of chickens transported and those dying as a result of their transport were recorded and analysed. Overall transport-related mortality of broiler chickens transported for slaughter in the Czech Republic was 0.37%. It ranged from 0.31% to 0.72%, the increase approximately corresponding to the increasing transport distance. Statistically highly significant (p<0.001) differences were found when comparing transport-related mortality rates in individual seasons of the year. The greatest mortality (0.55%) was associated with transports carried out in winter months whereas the lowest death losses (0.30%) were found in chickens transported for slaughter in summer months. Our study revealed greater transport-related mortality rates in broiler chickens transported for slaughter in the Czech Republic than expected when considering earlier studies. The most pronounced increases were found in transports for shorter distances and in winter months. However, an increase was found at all transport distances monitored except for distances exceeding 300 km and all seasons except for summer. Furthermore, a general increasing tendency in chicken losses during the monitored period was found. The particularly alarming finding is that the mortality of broiler chickens being transported to processing plants has been showing a long-term increasing tendency over the last two decades. Further research should focus on the identification of specific factors leading to such high and growing mortality rates and developing practical guidelines to improve the welfare of the birds in transit accordingly.

  6. Negative Trends in Transport-related Mortality Rates in Broiler Chickens

    PubMed Central

    Vecerek, Vladimir; Voslarova, Eva; Conte, Francesca; Vecerkova, Lenka; Bedanova, Iveta

    2016-01-01

    The high incidence of deaths during transport for slaughter is associated with poor welfare and represents a considerable loss to the poultry industry. In the period from 2009 to 2014, all shipments of broiler chickens to poultry processing plants were monitored in the Czech Republic and the numbers of chickens transported and those dying as a result of their transport were recorded and analysed. Overall transport-related mortality of broiler chickens transported for slaughter in the Czech Republic was 0.37%. It ranged from 0.31% to 0.72%, the increase approximately corresponding to the increasing transport distance. Statistically highly significant (p<0.001) differences were found when comparing transport-related mortality rates in individual seasons of the year. The greatest mortality (0.55%) was associated with transports carried out in winter months whereas the lowest death losses (0.30%) were found in chickens transported for slaughter in summer months. Our study revealed greater transport-related mortality rates in broiler chickens transported for slaughter in the Czech Republic than expected when considering earlier studies. The most pronounced increases were found in transports for shorter distances and in winter months. However, an increase was found at all transport distances monitored except for distances exceeding 300 km and all seasons except for summer. Furthermore, a general increasing tendency in chicken losses during the monitored period was found. The particularly alarming finding is that the mortality of broiler chickens being transported to processing plants has been showing a long-term increasing tendency over the last two decades. Further research should focus on the identification of specific factors leading to such high and growing mortality rates and developing practical guidelines to improve the welfare of the birds in transit accordingly. PMID:26954219

  7. Characterization of cross-linked cellulosic ion-exchange adsorbents: 2. Protein sorption and transport.

    PubMed

    Angelo, James M; Cvetkovic, Aleksandar; Gantier, Rene; Lenhoff, Abraham M

    2016-03-18

    Adsorption behavior in the HyperCel family of cellulosic ion-exchange materials (Pall Corporation) was characterized using methods to assess, quantitatively and qualitatively, the dynamics of protein uptake as well as static adsorption as a function of ionic strength and protein concentration using several model proteins. The three exchangers studied all presented relatively high adsorptive capacities under low ionic strength conditions, comparable to commercially available resins containing polymer functionalization aimed at increasing that particular characteristic. The strong cation- and anion-exchange moieties showed higher sensitivity to increasing salt concentrations, but protein affinity on the salt-tolerant STAR AX HyperCel exchanger remained strong at ionic strengths normally used in downstream processing to elute material fully during ion-exchange chromatography. Very high uptake rates were observed in both batch kinetics experiments and time-series confocal laser scanning microscopy, suggesting low intraparticle transport resistances relative to external film resistance, even at higher bulk protein concentrations where the opposite is typically observed. Electron microscopy imaging of protein adsorbed phases provided additional insight into particle structure that could not be resolved in previous work on the bare resins. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Characterization of Cross-Linked Cellulosic Ion-Exchange Adsorbents: 2. Protein Sorption and Transport

    PubMed Central

    Angelo, James M.; Cvetkovic, Aleksandar; Gantier, Rene; Lenhoff, Abraham M.

    2016-01-01

    Adsorption behavior in the HyperCel family of cellulosic ion-exchange materials (Pall Corporation) was characterized using methods to assess, quantitatively and qualitatively, the dynamics of protein uptake as well as static adsorption as a function of ionic strength and protein concentration using several model proteins. The three exchangers studied all presented relatively high adsorptive capacities under low ionic strength conditions, comparable to commercially available resins containing polymer functionalization aimed at increasing that particular characteristic. The strong cation- and anion-exchange moieties showed higher sensitivity to increasing salt concentrations, but protein affinity on the salt-tolerant STAR AX HyperCel exchanger remained strong at ionic strengths normally used in downstream processing to elute material fully during ion-exchange chromatography. Very high uptake rates were observed in both batch kinetics experiments and time-series confocal laser scanning microscopy, suggesting low intraparticle transport resistances relative to external film resistance, even at higher bulk protein concentrations where the opposite is typically observed. Electron microscopy imaging of protein adsorbed phases provided additional insight into particle structure that could not be resolved in previous work on the bare resins. PMID:26905881

  9. Effects of seasonal and interannual variability in along-shelf and cross-shelf transport on groundfish recruitment in the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Vestfals, Cathleen D.; Ciannelli, Lorenzo; Duffy-Anderson, Janet T.; Ladd, Carol

    2014-11-01

    The Bering Sea responds rapidly to atmospheric perturbations and over the past several decades has experienced extreme variability in both its physical and biological characteristics. These changes can impact organisms that inhabit the region, particularly marine fishes, as normal current patterns to which reproductive habits are tuned can be disrupted, which, in turn, may influence recruitment and population dynamics. To understand the influence of ocean circulation on groundfish recruitment in the eastern Bering Sea, we examined transport along and across the Bering Slope derived from 23 years (1982-2004) of simulations from a Regional Ocean Modeling System (ROMS) ocean circulation model. We expected that changes in the strength and position of the Bering Slope Current (BSC) would affect recruitment in selected species (Pacific cod, walleye pollock, Greenland halibut, Pacific halibut, and arrowtooth flounder), and that circulation features along and across the shelf edge would be strongly influenced by atmospheric forcing. Variability in along-shelf transport at three transects along the path of the BSC, cross-shelf transport across the 100 and 200 m isobaths, and transport through Unimak Pass were examined. Strong seasonal and interannual variations in flow were observed, with transport typically highest during fall and winter months, coinciding with timing of spawning activity in the five species. Significant correlations were found between transport, BSC position, and groundfish recruitment. Pacific cod, in particular, benefitted from decreased along-shelf and on-shelf flow, while Pacific halibut recruitment increased in relation to increased on-shelf transport through southern canyons. The results of this study improve our understanding of variability in circulation and associated effects on groundfish recruitment in the eastern Bering Sea.

  10. Cross talk between ABC transporter mRNAs via a target mRNA-derived sponge of the GcvB small RNA

    PubMed Central

    Miyakoshi, Masatoshi; Chao, Yanjie; Vogel, Jörg

    2015-01-01

    There is an expanding list of examples by which one mRNA can posttranscriptionally influence the expression of others. This can involve RNA sponges that sequester regulatory RNAs of mRNAs in the same regulon, but the underlying molecular mechanism of such mRNA cross talk remains little understood. Here, we report sponge-mediated mRNA cross talk in the posttranscriptional network of GcvB, a conserved Hfq-dependent small RNA with one of the largest regulons known in bacteria. We show that mRNA decay from the gltIJKL locus encoding an amino acid ABC transporter generates a stable fragment (SroC) that base-pairs with GcvB. This interaction triggers the degradation of GcvB by RNase E, alleviating the GcvB-mediated mRNA repression of other amino acid-related transport and metabolic genes. Intriguingly, since the gltIJKL mRNA itself is a target of GcvB, the SroC sponge seems to enable both an internal feed-forward loop to activate its parental mRNA in cis and activation of many trans-encoded mRNAs in the same pathway. Disabling this mRNA cross talk affects bacterial growth when peptides are the sole carbon and nitrogen sources. PMID:25630703

  11. Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties

    NASA Astrophysics Data System (ADS)

    Swanson, Ryan D.; Binley, Andrew; Keating, Kristina; France, Samantha; Osterman, Gordon; Day-Lewis, Frederick D.; Singha, Kamini

    2015-02-01

    The advection-dispersion equation (ADE) fails to describe commonly observed non-Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual-domain mass-transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct-current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non-Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column-scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more-mobile and less-mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material-dependent and flow-dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.

  12. Indian MST radar: A remote sensing tool for studying long- and short- term cross tropopause transports

    NASA Astrophysics Data System (ADS)

    Das, Siddarth Shankar; Ratnam, Madineni Venkat; Suneeth, K. V.

    The stratospheric air is dry and ozone rich in nature, whereas the tropospheric air is enriched in humidity with high aerosol concentration. The tropopause is the stable layer which acts as a semi-permeable membrane between these two spheres (i.e. troposphere and stratosphere) and thus hinders the exchange of the minors constituents (e.g. water vapour and ozone) between these two spheres. This complex equilibrium region is known as the upper troposphere and lower stratosphere (UTLS) region. The major mixing process befalls over the tropical region, where the maximum convective systems occur through the tropical tropopause layer (TTL). Thus, it is necessary to understand the dynamical and chemical processes that occurring at UTLS region and quantative analysis of the mass exchange is essential. Ten years of data obtained from Indian MST radar located at a Tropical station Gadanki (13.5oN, 79.2oE) is used to study the long- and short (event) term cross tropopause transport. The prime mechanisms responsible for the radar backscattering echoes are isotropic/anisotropic turbulence fluctuations in the refractive index and Fresnel reflection/scattering due to sharp gradients in the radio refractive index. The inhomogeneties in the radio refractive index are contributed by both humidity and temperature below 8 km height, whereas above it, it is only contributed by the temperature gradients. When the dry stratospheric air penetrates into the troposphere, it will take some time to mix with the humid air of troposphere. Due to two different constituents of the air, there will be strong refractive index gradient, which will be reflected as enhanced radar backscattering echoes. The dry stratospheric air will slowly mix with the humid tropospheric air by means of small scale turbulence. Using this scattering mechanism behavior, the long-term and its seasonal characteristics, and the short-term event wise (convective disturbances) stratospheric air intrusion into the troposphere

  13. Relative intermolecular orientation probed via molecular heat transport.

    PubMed

    Chen, Hailong; Bian, Hongtao; Li, Jiebo; Wen, Xiewen; Zheng, Junrong

    2013-07-25

    In this work, through investigating a series of liquid, glassy, and crystalline samples with ultrafast multiple-mode 2D IR and IR transient absorption methods, we demonstrated that the signal anisotropy of vibrational relaxation-induced heat effects is determined by both relative molecular orientations and molecular rotations. If the relative molecular orientations are randomized or molecular rotations are fast compared to heat transfer, the signal anisotropy of heat effects is zero. If the relative molecular orientations are anisotropic and the molecular rotations are slow, the signal anisotropy of heat effects can be nonzero, which is determined by the relative orientations of the energy source mode and the heat sensor mode within the same molecule and in different molecules. We also demonstrated that the correlation between the anisotropy value of heat signal and the relative molecular orientations can be quantitatively calculated.

  14. Momentum transport cross-section measurements for potassium and rubidium in rare gases and white light-induced separation of rubidium isotopes

    SciTech Connect

    Mugglin, D.T.

    1993-12-31

    This dissertation is concerned with two light-induced kinetic effects, light-induced diffusive pulling and light-induced drift. We use a light-induced diffusive pulling experiment to measure the ground state velocity-changing collision cross section (related to the momentum transport cross section and the diffusion coefficient) and the relative difference ({Delta}{sigma}/{sigma}) of the excited and ground state cross sections with respect to that of the ground state for potassium mixed with inert buffer gases. The measured excited state cross section is a weighted average of the potassium 4{sup 2}P{sub 1/2} and 4{sup 2}P{sub 3/2} fine structure levels, which are mixed by collisions with inert gas atoms. For the ground state cross sections, we obtain the following experimental results for potassium mixed with He, Ne, Ar, Kr, and Xe, respectively: 52 {+-} 4, 57 {+-} 8, 61 {+-} 5, 43 {+-} 5, and 60 {+-}5 {angstrom}{sup 2}. For {Delta}{sigma}/{sigma}, we obtain the following (in the same order): 0.085 {+-} 0.010, 0.058 {+-} 0.006, 0.41 {+-} 0.03, 0.43 {+-} 0.03, and 0.61 {+-} 0.05. For potassium-Ne and potassium-Ar, we combine these measurements with light-induced drift measurements of the ratio {Delta}{sigma}(J = 3/2) : {Delta}{sigma}(J = 1/2) to obtain absolute transport cross sections for the individual 4{sup 2}S{sub 1/2}, 4{sup 2}P{sub 1/2}, and 4{sup 2}P{sub 3/2} levels. We also use the light-induced diffusive pulling experimental method to measure {Delta}{sigma}/{sigma} for Rb-inert gas mixtures. We obtain values for the ground state diffusion cross section for Rb in several of the inert gases as well. We report the first experimental observation of the separation of two isotopes using broadband light by the process of white light-induced drift. For a light source, we use a broadband laser with an acousto-optic modulator as an output coupler. We verify the separation of the {sup 85}Rb and {sup 87}Rb isotopes.

  15. 49 CFR 236.787 - Protection, cross.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Protection, cross. 236.787 Section 236.787 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Protection, cross. An arrangement to prevent the improper operation of a signal, switch, movable-point...

  16. 49 CFR 236.787 - Protection, cross.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Protection, cross. 236.787 Section 236.787 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Protection, cross. An arrangement to prevent the improper operation of a signal, switch, movable-point...

  17. Conservation of targeting but divergence in function and quality control of peroxisomal ABC transporters: an analysis using cross-kingdom expression.

    PubMed

    Zhang, Xuebin; De Marcos Lousa, Carine; Schutte-Lensink, Nellie; Ofman, Rob; Wanders, Ronald J; Baldwin, Stephen A; Baker, Alison; Kemp, Stephan; Theodoulou, Frederica L

    2011-06-15

    ABC (ATP-binding cassette) subfamily D transporters are found in all eukaryotic kingdoms and are known to play essential roles in mammals and plants; however, their number, organization and physiological contexts differ. Via cross-kingdom expression experiments, we have explored the conservation of targeting, protein stability and function between mammalian and plant ABCD transporters. When expressed in tobacco epidermal cells, the mammalian ABCD proteins ALDP (adrenoleukodystrophy protein), ALDR (adrenoleukodystrophy-related protein) and PMP70 (70 kDa peroxisomal membrane protein) targeted faithfully to peroxisomes and P70R (PMP70-related protein) targeted to the ER (endoplasmic reticulum), as in the native host. The Arabidopsis thaliana peroxin AtPex19_1 interacted with human peroxisomal ABC transporters both in vivo and in vitro, providing an explanation for the fidelity of targeting. The fate of X-linked adrenoleukodystrophy disease-related mutants differed between fibroblasts and plant cells. In fibroblasts, levels of ALDP in some 'protein-absent' mutants were increased by low-temperature culture, in some cases restoring function. In contrast, all mutant ALDP proteins examined were stable and correctly targeted in plant cells, regardless of their fate in fibroblasts. ALDR complemented the seed germination defect of the Arabidopsis cts-1 mutant which lacks the peroxisomal ABCD transporter CTS (Comatose), but neither ALDR nor ALDP was able to rescue the defect in fatty acid β-oxidation in establishing seedlings. Taken together, our results indicate that the mechanism for trafficking of peroxisomal membrane proteins is shared between plants and mammals, but suggest differences in the sensing and turnover of mutant ABC transporter proteins and differences in substrate specificity and/or function.

  18. Generalized balance equations for charged particle transport via localized and delocalized states: Mobility, generalized Einstein relations, and fractional transport

    NASA Astrophysics Data System (ADS)

    Stokes, Peter W.; Philippa, Bronson; Cocks, Daniel; White, Ronald D.

    2017-04-01

    A generalized phase-space kinetic Boltzmann equation for highly nonequilibrium charged particle transport via localized and delocalized states is used to develop continuity, momentum, and energy balance equations, accounting explicitly for scattering, trapping and detrapping, and recombination loss processes. Analytic expressions detail the effect of these microscopic processes on mobility and diffusivity. Generalized Einstein relations (GER) are developed that enable the anisotropic nature of diffusion to be determined in terms of the measured field dependence of the mobility. Interesting phenomena such as negative differential conductivity and recombination heating and cooling are shown to arise from recombination loss processes and the localized and delocalized nature of transport. Fractional transport emerges naturally within this framework through the appropriate choice of divergent mean waiting time distributions for localized states, and fractional generalizations of the GER and mobility are presented. Signature impacts on time-of-flight current transients of recombination loss processes via both localized and delocalized states are presented.

  19. On different regime relations between bed load transport and bed topography

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Ma, H.; Fu, X.; Duan, J. G.

    2016-12-01

    Bed load transport is determined by the effective part of the total shear stress subtracting the form drag that arises from bed topography. Wang et al. (2004) quantified the overall topographic roughness of the channel bed with the parameter Sp and claimed that the increasing Sp corresponds with increasing flow resistance and decreasing bed load transport rate due to increasing form drag and decreasing skin friction. However, the flume experiments for non-uniform sediment transport on steep slope at the University of Arizona show opposite results that bed load transport increases with Sp. We investigate the physical reason of the contrasting results for the full understanding of the different regimes between bed load transport and bed topography. We develop the energy conveyance equation for water flow and bed load transport and apply it to the development of the equilibrium relation between bed load transport and energy dissipation due to the form drag. The energy theory for bed load transport shows that since our flume experiments achieved the equilibrium transport state with water and sediment circulating supplying, the bed topography Sp is determined by the flow and sediment grain size, and the bed load transport is positively related to the energy dissipation rate which is thus positively related to Sp. However, in the field experiment of Wang et al. (2004), at first, the referenced Sp is determined by the most recent significant flood whereas the bed load transport is always below the transport capacity with insufficient sediment supply. After one-time sediment feed, the bed load transport rapidly varies from ephemeral full capacity state to sediment starving state. In this process, the removal of relative fine sediment results in the rapid increment of Sp from the instant equilibrium state to the referenced Sp whereas the coarsen bed leads to decrement of bed load transport. Eventually, the sediment starving state results in the increasing Sp and decreasing

  20. CO2-ECBM related coupled physical and mechanical transport processes

    NASA Astrophysics Data System (ADS)

    Gensterblum, Y.; Sartorius, M.; Busch, A.; Krooss, B. M.; Littke, R.

    2012-12-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a subbituminous A coal from the Surat Basin, Queensland Australia (figure). From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg-corrected permeability depends on gas type. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa, with increasing mean pore pressure at lower confining pressure an increase in permeability is observed, which is attributed to a widening of cleat aperture. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane and CO2. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals was significantly lower (by 50%) than that of dry coals, no hysteresis was observed between sorption and desorption on dry and moisture-equilibrated samples and the

  1. Transport pathways of carbon monoxide in the Asian summer monsoon diagnosed from Model of Ozone and Related Tracers (MOZART)

    NASA Astrophysics Data System (ADS)

    Park, Mijeong; Randel, William J.; Emmons, Louisa K.; Livesey, Nathaniel J.

    2009-04-01

    Satellite observations of tropospheric chemical constituents (such as carbon monoxide, CO) reveal a persistent maximum in the upper troposphere-lower stratosphere (UTLS) associated with the Asian summer monsoon anticyclone. Diagnostic studies suggest that the strong anticyclonic circulation acts to confine air masses, but the sources of pollution and transport pathways to altitudes near the tropopause are the subject of debate. Here we use the Model for Ozone and Related Tracers 4 (MOZART-4) global chemistry transport model, driven by analyzed meteorological fields, to study the source and transport of CO in the Asian monsoon circulation. A MOZART-4 simulation for one summer is performed, and results are compared with satellite observations of CO from the Aura Microwave Limb Sounder and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer. Overall, good agreement is found between the modeled and observed CO in the UTLS, promoting confidence in the model simulation. The model results are then analyzed to understand the sources and transport pathways of CO in the Asian monsoon region, and within the anticyclone in particular. The results show that CO is transported upward by monsoon deep convection, with the main surface sources from India and Southeast Asia. The uppermost altitude of the convective transport is ˜12 km, near the level of main deep convective outflow, and much of the CO is then advected in the upper troposphere northeastward across the Pacific Ocean and southwestward with the cross-equatorial Hadley flow. However, some of the CO is also advected vertically to altitudes near the tropopause (˜16 km) by the large-scale upward circulation on the eastern side of the anticyclone, and this air then becomes trapped within the anticyclone (to the west of the convection, extending to the Middle East). Within the anticyclone, the modeled CO shows a relative maximum near 15 km, in good agreement with observations.

  2. Steady State Chaotic Magnetic Fields and Particle Dynamics Cross-field Transport of Particles in Chaotic Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Dasgupta, B.; Ram, A.

    2009-12-01

    The observed propagation of cosmic rays in the interplanetary space cannot be explained unless there is diffusion of the energetic particles across the interplanetary magnetic field. The cross-field diffusion of cosmic rays is assumed to be due to the chaotic nature of the interplanetary/intergalactic magnetic fields. Among the classic works on this subject have been those of Parker [1] and Jokipii [2]. Parker considered the passage of cosmic ray particles and energetic solar particles in a large scale magnetic field containing small scale irregularities. In the context of cosmic ray propagation, Jokipii considered a small fluctuating component, added on to a uniform magnetic field, to study the spatial transport of particles. We consider asymmetric, steady-state magnetic fields, in three spatial dimensions, generated by currents flowing in circular loops and straight lines [3]. We find that under very special circumstances can one generate large scale coherent magnetic fields. In general, even simple asymmetric current configurations generate spatially chaotic magnetic fields in three-dimensions. The motion of charged particles in these chaotic magnetic fields is quite coherent. This is a surprising result as one generally assumes that spatially chaotic magnetic fields will give rise to chaotic particle motion. So chaotic magnetic fields by themselves do not lead to cross-field transport. However, if we consider a current system, e.g., a current loop, embedded in a uniform magnetic field then a particle can undergo cross-field transport. For cross-field diffusion of charged particles it is necessary that the magnetic field lines be three dimensional. [1] E.N. Parker, Planet. Space Sci. 13, 9, (1965) [2] J.R. Jokipii, Astrophys. J. 146, 480, (1966). [3] A.K. Ram and B. Dasgupta, in 35th EPS Conference on Plasma Phys. Hersonissos, ECA Vol.32D, O-4.059 (2008); and Eos Trans. AGU 88 (52), Fall Meet. Suppl. Abstract NG21B-0522 (2007).

  3. Cross-continental comparison of the association between the physical environment and active transportation in children: a systematic review.

    PubMed

    D'Haese, Sara; Vanwolleghem, Griet; Hinckson, Erica; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Van Dyck, Delfien; Cardon, Greet

    2015-11-26

    The purpose of this systematic review was to determine the relationship between a wide range of physical environmental characteristics and different contexts of active transportation in 6- to 12-year-old children across different continents. A systematic search was conducted in six databases (Pubmed, Web of Science, Cinahl, SportDiscus, TRIS and Cochrane) resulting in 65 papers, eligible for inclusion. The investigated physical environmental variables were grouped into six categories: walkability, accessibility, walk/cycle facilities, aesthetics, safety, recreation facilities. The majority of the studies were conducted in North America (n = 35), Europe (n = 17) and Australia (n = 11). Active transportation to school (walking or cycling) was positively associated with walkability. Walking to school was positively associated with walkability, density and accessibility. Evidence for a possible association was found for traffic safety and all forms of active transportation to school. No convincing evidence was found for associations between the physical environment and active transportation during leisure. General safety and traffic safety were associated with active transportation to school in North America and Australia but not associated with active transportation to school in Europe. The physical environment was mainly associated with active transportation to school. Continent specific associations were found, indicating that safety measures were most important in relation to active commuting to school in North America and Australia. There is a need for longitudinal studies and studies conducted in Asia, Africa and South-America and studies focusing specifically on active transportation during leisure.

  4. Nonequilibrium thermal transport and its relation to linear response

    NASA Astrophysics Data System (ADS)

    Karrasch, C.; Ilan, R.; Moore, J. E.

    2013-11-01

    We study the real-time dynamics of spin chains driven out of thermal equilibrium by an initial temperature gradient TL≠TR using density matrix renormalization group methods. We demonstrate that the nonequilibrium energy current saturates fast to a finite value if the linear-response thermal conductivity is infinite, i.e., if the Drude weight D is nonzero. Our data suggest that a nonintegrable dimerized chain might support such dissipationless transport (D>0). We show that the steady-state value JE of the current for arbitrary TL≠TR is of the functional form JE=f(TL)-f(TR), i.e., it is completely determined by the linear conductance. We argue for this functional form, which is essentially a Stefan-Boltzmann law in this integrable model; for the XXX ferromagnet, f can be computed via the thermodynamic Bethe ansatz in good agreement with the numerics. Inhomogeneous systems exhibiting different bulk parameters as well as Luttinger liquid boundary physics induced by single impurities are discussed briefly.

  5. Application of GPS for transportation related engineering surveys

    NASA Astrophysics Data System (ADS)

    Merrell, Roger L.

    1986-09-01

    The Texas State Department of Highways and Public Transportation (SDHPT) has been using GPS for over two years to establish primary geodetic reference points for engineering projects and mapping control. In accordance with a Five Year GPS Implementation Plant developed in 1982, four GPS, unmanned, automatic Regional Reference Point (RRP) stations will be installed by September 1, 1986. Five additional stations are planned as justified. Each RRP will consist of a dual frequency GPS receiver that will ultimately track the satellites continuously. Operation of the receiver, telecommunications and other station keeping chores will be handled by a microcomputer. The RRP station network will be controlled through another centrally located microcomputer which is also interfaced with a larger mainframe system. Each RRP is designed to service an area bounded by a 200 KM radius and will act as the “other” receiver for roving field units operating in a GPS differential measurement mode. In order to meet the installation schedule, early decisions are being made concerning satellite tracking rates, operational scenarios, and telecommunications to facilitate development of the basic hardware and software systems. A period of continual enhancement to hardware, software and RRP operational procedures is expected as GPS technology expands.

  6. Patterns of Adult Cross-Racial Friendships: A Context for Understanding Contemporary Race Relations

    PubMed Central

    Plummer, Deborah L.; Allison, Jeroan; Stone, Rosalie Torres; Powell, Lauren

    2016-01-01

    Objectives This study examined patterns, characteristics, and predictors of cross-racial friendships as the context for understanding contemporary race relations. Methods A national survey included 1,055 respondents, of whom 55% was white, 32% was black, and 74% was female; ages ranged from 18 to ≥ 65 years. Focus groups were conducted to assess societal and personal benefits. Participants (n=31) were racially diverse and aged 20–66 years. Results After accounting for multiple covariates, regression analysis revealed that Asians, Hispanics, and multiracial individuals are more likely than their white and black counterparts to have cross-racial friends. Females were less likely than males to have eight or more cross-racial friends. Regression analysis revealed that the depth of cross-racial friendships was greater for women than men and for those who shared more life experiences. Increasing age was associated with lower cross-racial friendship depth. Qualitative analysis of open-ended questions and focus group data established the social context as directly relevant to the number and depth of friendships. Despite the level of depth in cross-racial friendships, respondents described a general reluctance to discuss any racially charged societal events, such as police shootings of unarmed black men. Conclusion This study identified salient characteristics of individuals associated with cross-racial friendships and highlighted the influence of the social, historical, and political context in shaping such friendships. Our findings suggest that contemporary race relations reflect progress as well as polarization. PMID:27077797

  7. Inter-hemispheric differences in energy budgets and surface temperature anomalies during the 20th Century: the role of cross-equatorial transport anomalies

    NASA Astrophysics Data System (ADS)

    Lembo, Valerio; Folini, Doris; Wild, Martin; Lionello, Piero

    2017-04-01

    Two different ensembles of the CMIP5 simulations for the historical period (1850-2005) have been analysed, either including solely the spatially homogeneous GHG forcing (GHG) or the mix of all forcings representative of the period (ALL). We focus our attention on the TOA energy budget (Bt) anomalies, near-surface temperature anomalies (T2m) anomalies and cross-equatorial energy transport (CET) anomalies. We find that Bt anomalies are evidently hemispherically asymmetric in the ALL scenario, whereas in GHG T2m anomalies are asymmetric. The larger warming ratio of the NH compared to the SH in GHG is likely attributable to the different heat capacity of land and oceans, being the forcing homogeneous. Looking at the shortwave (SW) and longwave (LW) components (St and Lt respectively) of Bt, the increasing SW absorption is largely compensated by increasing LW emission in GHG, whereas in ALL it is combined to a decreasing LW emission, particularly in the SH. CET anomalies have a positive trend in the ALL scenario, implying an increased northward total heat transport, mainly by means of the oceans. The trend is negative in the GHG scenario, mainly by means of the atmosphere, implying either a decreased northward heat transport or an increased southward transport, depending on the model. The model spread critically affects the capability to relate CET anomalies to either Bt or T2m inter-hemispheric difference anomalies.

  8. Structure-properties relation for random networks of fibers with noncircular cross section

    NASA Astrophysics Data System (ADS)

    Deogekar, S.; Picu, R. C.

    2017-03-01

    The mechanical behavior of three-dimensional cross-linked random fiber networks composed from fibers of noncircular cross section characterized by two principal moments of inertia is studied in this work. Such fibers store energy in the axial deformation mode and two bending modes of unequal stiffness. We show that the torsional stiffness of fibers becomes important as it determines the relative contribution of the two bending modes to the overall deformation. The scaling of the small strain modulus with the network parameters is established. The large strain deformation of these structures is less sensitive to the shape of the cross section.

  9. Structure-properties relation for random networks of fibers with noncircular cross section.

    PubMed

    Deogekar, S; Picu, R C

    2017-03-01

    The mechanical behavior of three-dimensional cross-linked random fiber networks composed from fibers of noncircular cross section characterized by two principal moments of inertia is studied in this work. Such fibers store energy in the axial deformation mode and two bending modes of unequal stiffness. We show that the torsional stiffness of fibers becomes important as it determines the relative contribution of the two bending modes to the overall deformation. The scaling of the small strain modulus with the network parameters is established. The large strain deformation of these structures is less sensitive to the shape of the cross section.

  10. 31 CFR 585.207 - Prohibited transportation-related transactions involving the FRY (S&M).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transactions involving the FRY (S&M). 585.207 Section 585.207 Money and Finance: Treasury Regulations Relating... transactions involving the FRY (S&M). Except as otherwise authorized, the following are prohibited: (a) Any... transportation to or from the FRY (S&M); (b) The provision of transportation to or from the United States by:...

  11. Effect of end-group cross-linking on transport properties of sulfonated poly(phenylene sulfide nitrile)s for proton exchange membranes

    NASA Astrophysics Data System (ADS)

    Kang, Na Rae; Lee, So Young; Shin, Dong Won; Hwang, Doo Sung; Lee, Kang Hyuck; Cho, Doo Hee; Kim, Ji Hoon; Lee, Young Moo

    2016-03-01

    A series of end-group cross-linked membranes (Az-XESPSN) were prepared by click reaction to investigate the effects of cross-linking on the morphology and proton transport properties of proton exchange membranes. The morphological transformations resulting from thermal annealing and cross-linking were observed by means of atomic force microscopy (AFM) and transmission electron microscopy (TEM). Compared to the non-cross-linked ESPSN membranes, the Az-XESPSN membranes exhibited lower water uptake and improved mechanical and chemical stabilities. In addition, the Az-XESPSN membranes exhibited higher proton conductivities (0.018-0.028 S cm-1) compared to those of the ESPSN membranes (0.0044-0.0053 S cm-1) and Nafion 212 (0.0061 S cm-1), particularly in conditions of elevated temperature (120 °C) and low relative humidity (35%). Such enhancements can be attributed to a synergistic effect of well-defined hydrophilic ionic clusters and triazole groups that function as proton carriers under anhydrous conditions. Furthermore, the Az-XESPSN membranes exhibited significantly enhanced single cell performance and long-term stability compared to those of ESPSN membranes.

  12. CO2-ECBM related coupled physical and mechanical transport processes

    NASA Astrophysics Data System (ADS)

    Gensterblum, Y.; Sartorius, M.; Busch, A.; Cumming, D.; Krooss, B. M.

    2012-04-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a sub bituminous A coal from the Surat Basin, Queensland Australia. From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg corrected permeability shows a gas type dependence. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa we observe with increasing mean pressure at lower confining pressure an increase in permeability which we attribute to a cleat aperture widening. The cleat volume compressibility (cf) also shows a dependence on the mean pore pressure. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. This permeability hysteresis is in accordance with results reported by Harpalani and McPherson (1985). The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals

  13. CO2-ECBM related coupled physical and mechanical transport processes

    NASA Astrophysics Data System (ADS)

    Gensterblum, Yves; Satorius, Michael; Busch, Andreas; Krooß, Bernhard

    2013-04-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a sub bituminous A coal from the Surat Basin, Queensland Australia. From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg corrected permeability shows a gas type dependence. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa we observe with increasing mean pressure at lower confining pressure an increase in permeability which we attribute to a cleat aperture widening. The cleat volume compressibility (cf) also shows a dependence on the mean pore pressure. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. This permeability hysteresis is in accordance with results reported by Harpalani and McPherson (1985). The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals

  14. Natriuretic Hormones, Endogenous Ouabain, and Related Sodium Transport Inhibitors

    PubMed Central

    Hamlyn, John M.

    2014-01-01

    The work of deWardener and colleagues stimulated longstanding interest in natriuretic hormones (NHs). In addition to the atrial peptides (APs), the circulation contains unidentified physiologically relevant NHs. One NH is controlled by the central nervous system (CNS) and likely secreted by the pituitary. Its circulating activity is modulated by salt intake and the prevailing sodium concentration of the blood and intracerebroventricular fluid, and contributes to postprandial and dehydration natriuresis. The other NH, mobilized by atrial stretch, promotes natriuresis by increasing the production of intrarenal dopamine and/or nitric oxide (NO). Both NHs have short (<35 min) circulating half lives, depress renotubular sodium transport, and neither requires the renal nerves. The search for NHs led to endogenous cardiotonic steroids (CTS) including ouabain-, digoxin-, and bufadienolide-like materials. These CTS, given acutely in high nanomole to micromole amounts into the general or renal circulations, inhibit sodium pumps and are natriuretic. Among these CTS, only bufalin is cleared sufficiently rapidly to qualify for an NH-like role. Ouabain-like CTS are cleared slowly, and when given chronically in low daily nanomole amounts, promote sodium retention, augment arterial myogenic tone, reduce renal blood flow and glomerular filtration, suppress NO in the renal vasa recta, and increase sympathetic nerve activity and blood pressure. Moreover, lowering total body sodium raises circulating endogenous ouabain. Thus, ouabain-like CTS have physiological actions that, like aldosterone, support renal sodium retention and blood pressure. In conclusion, the mammalian circulation contains two non-AP NHs. Identification of the CNS NH should be a priority. PMID:25520702

  15. Source-related transport of phosphorus in surface runoff.

    PubMed

    Shigaki, Francirose; Sharpley, Andrew; Prochnow, Luís Ignácio

    2006-01-01

    Continual application of mineral fertilizer and manures to meet crop production goals has resulted in the buildup of soil P concentrations in many areas. A rainfall simulation study was conducted to evaluate the effect of the application of P sources differing in water-soluble P (WSP) concentration on P transport in runoff from two grassed and one no-till soil (2 m(2) plots). Triple superphosphate (TSP)-79% WSP, low-grade single superphosphate (LGSSP)-50% WSP, North Carolina rock phosphate (NCRP)-0.5% WSP, and swine manure (SM)-30% WSP, were broadcast (100 kg total P ha(-1)) and simulated rainfall (50 mm h(-1) for 30 min of runoff) applied 1, 7, 21, and 42 d after P source application. In the first rainfall event one d after fertilizer application, dissolved reactive P (DRP) and total P (TP) concentrations of runoff increased (P < 0.05) for all soils with an increase of source WSP; with DRP averaging 0.27, 0.50, 14.66, 41.69, and 90.47 mg L(-1); and total P averaging 0.34, 0.61, 19.05, 43.10, and 98.06 mg L(-1) for the control, NCRP, SM, LGSSP, and TSP, respectively. The loss of P in runoff decreased with time for TSP and SM, such that after 42 d, losses from TSP, SM, and LGSSP did not differ. These results support that P water solubility in P sources may be considered as an indicator of P loss potential.

  16. Reading Retardation and Cross-Laterality in Relation to Short-Term Information Processing Tasks

    ERIC Educational Resources Information Center

    Wheeler, T. J.; And Others

    1977-01-01

    Predicts that ill-established cerebral dominance, as indicated by the problems of cross-laterality, would be related both to a limitation in information processing "irrespective of the type of information" (probably manifesting itself even with relatively small amounts of information) and significantly to reading retardation. (Author/RK)

  17. TRANSPORT

    EPA Science Inventory

    Presentation outline: transport principles, effective solubility; gasoline composition; and field examples (plume diving).
    Presentation conclusions: MTBE transport follows from - phyiscal and chemical properties and hydrology. Field examples show: MTBE plumes > benzene plu...

  18. Quantification of tracer plume transport parameters in 2D saturated porous media by cross-borehole ERT imaging

    NASA Astrophysics Data System (ADS)

    Lekmine, G.; Auradou, H.; Pessel, M.; Rayner, J. L.

    2017-04-01

    Cross-borehole ERT imaging was tested to quantify the average velocity and transport parameters of tracer plumes in saturated porous media. Seven tracer tests were performed at different flow rates and monitored by either a vertical or horizontal dipole-dipole ERT sequence. These sequences were tested to reconstruct the shape and temporally follow the spread of the tracer plumes through a background regularization procedure. Data sets were inverted with the same inversion parameters and 2D model sections of resistivity ratios were converted to tracer concentrations. Both array types provided an accurate estimation of the average pore velocity vz. The total mass Mtot recovered was always overestimated by the horizontal dipole-dipole and underestimated by the vertical dipole-dipole. The vertical dipole-dipole was however reliable to quantify the longitudinal dispersivity λz, while the horizontal dipole-dipole returned better estimation for the transverse component λx. λ and Mtot were mainly influenced by the 2D distribution of the cumulated electrical sensitivity and the Shadow Effects induced by the third dimension. The size reduction of the edge of the plume was also related to the inability of the inversion process to reconstruct sharp resistivity contrasts at the interface. Smoothing was counterbalanced by a non-realistic rise of the ERT concentrations around the centre of mass returning overpredicted total masses. A sensitivity analysis on the cementation factor m and the porosity ϕ demonstrated that a change in one of these parameters by 8% involved non negligible variations by 30 and 40% of the dispersion coefficients and mass recovery.

  19. Regulation of NH4+ transport by essential cross talk between AMT monomers through the carboxyl tails.

    PubMed

    Neuhäuser, Benjamin; Dynowski, Marek; Mayer, Maria; Ludewig, Uwe

    2007-04-01

    Ammonium transport across plant plasma membranes is facilitated by AMT/Rh-type ammonium transporters (AMTs), which also have homologs in most organisms. In the roots of the plant Arabidopsis (Arabidopsis thaliana), AMTs have been identified that function directly in the high-affinity NH4+ acquisition from soil. Here, we show that AtAMT1;2 has a distinct role, as it is located in the plasma membrane of the root endodermis. AtAMT1;2 functions as a comparatively low-affinity NH4+ transporter. Mutations at the highly conserved carboxyl terminus (C terminus) of AMTs, including one that mimics phosphorylation at a putative phosphorylation site, impair NH4+ transport activity. Coexpressing these mutants along with wild-type AtAMT1;2 substantially reduced the activity of the wild-type transporter. A molecular model of AtAMT1;2 provides a plausible explanation for the dominant inhibition, as the C terminus of one monomer directly contacts the neighboring subunit. It is suggested that part of the cytoplasmic C terminus of a single monomer can gate the AMT trimer. This regulatory mechanism for rapid and efficient inactivation of NH4+ transporters may apply to several AMT members to prevent excess influx of cytotoxic ammonium.

  20. Estimation of short-time cross-correlation between frequency bands of event related EEG.

    PubMed

    Zygierewicz, J; Mazurkiewicz, J; Durka, P J; Franaszczuk, P J; Crone, N E

    2006-10-30

    Simultaneous variations of the event-related power changes (ERD/ERS) are often observed in a number of frequency bands. ERD/ERS measures are usually based on the relative changes of power in a given single frequency band. Within such an approach one cannot answer questions concerning the mutual relations between the band-power variations observed in different frequency bands. This paper addresses the problem of estimating and assessing the significance of the average cross-correlation between ERD/ERS phenomena occurring in two frequency bands. The cross-correlation function in a natural way also provides estimation of the delay between ERD/ERS in those bands. The proposed method is based on estimating the short-time cross-correlation function between relative changes of power in two selected frequency bands. The cross-correlation function is estimated in each trial separately and then averaged across trials. The significance of those mean cross-correlation functions is evaluated by means of a nonparametric test. The basic properties of the method are presented on simulated signals, and an example application to real EEG and ECoG signals is given.

  1. Older adults’ transportation walking: a cross-sectional study on the cumulative influence of physical environmental factors

    PubMed Central

    2013-01-01

    Background The physical environment may play a crucial role in promoting older adults’ walking for transportation. However, previous studies on relationships between the physical environment and older adults’ physical activity behaviors have reported inconsistent findings. A possible explanation for these inconsistencies is the focus upon studying environmental factors separately rather than simultaneously. The current study aimed to investigate the cumulative influence of perceived favorable environmental factors on older adults’ walking for transportation. Additionally, the moderating effect of perceived distance to destinations on this relationship was studied. Methods The sample was comprised of 50,685 non-institutionalized older adults residing in Flanders (Belgium). Cross-sectional data on demographics, environmental perceptions and frequency of walking for transportation were collected by self-administered questionnaires in the period 2004-2010. Perceived distance to destinations was categorized into short, medium, and large distance to destinations. An environmental index (=a sum of favorable environmental factors, ranging from 0 to 7) was constructed to investigate the cumulative influence of favorable environmental factors. Multilevel logistic regression analyses were applied to predict probabilities of daily walking for transportation. Results For short distance to destinations, probability of daily walking for transportation was significantly higher when seven compared to three, four or five favorable environmental factors were present. For medium distance to destinations, probabilities significantly increased for an increase from zero to four favorable environmental factors. For large distance to destinations, no relationship between the environmental index and walking for transportation was observed. Conclusions Our findings suggest that the presence of multiple favorable environmental factors can motivate older adults to walk medium distances

  2. Older adults' transportation walking: a cross-sectional study on the cumulative influence of physical environmental factors.

    PubMed

    Van Cauwenberg, Jelle; Clarys, Peter; De Bourdeaudhuij, Ilse; Van Holle, Veerle; Verté, Dominique; De Witte, Nico; De Donder, Liesbeth; Buffel, Tine; Dury, Sarah; Deforche, Benedicte

    2013-08-14

    The physical environment may play a crucial role in promoting older adults' walking for transportation. However, previous studies on relationships between the physical environment and older adults' physical activity behaviors have reported inconsistent findings. A possible explanation for these inconsistencies is the focus upon studying environmental factors separately rather than simultaneously. The current study aimed to investigate the cumulative influence of perceived favorable environmental factors on older adults' walking for transportation. Additionally, the moderating effect of perceived distance to destinations on this relationship was studied. The sample was comprised of 50,685 non-institutionalized older adults residing in Flanders (Belgium). Cross-sectional data on demographics, environmental perceptions and frequency of walking for transportation were collected by self-administered questionnaires in the period 2004-2010. Perceived distance to destinations was categorized into short, medium, and large distance to destinations. An environmental index (=a sum of favorable environmental factors, ranging from 0 to 7) was constructed to investigate the cumulative influence of favorable environmental factors. Multilevel logistic regression analyses were applied to predict probabilities of daily walking for transportation. For short distance to destinations, probability of daily walking for transportation was significantly higher when seven compared to three, four or five favorable environmental factors were present. For medium distance to destinations, probabilities significantly increased for an increase from zero to four favorable environmental factors. For large distance to destinations, no relationship between the environmental index and walking for transportation was observed. Our findings suggest that the presence of multiple favorable environmental factors can motivate older adults to walk medium distances to facilities. Future research should focus

  3. Charged-particle transport in gases in electric and magnetic fields crossed at arbitrary angles: Multiterm solution of Boltzmann's equation.

    PubMed

    White, R D; Ness, K F; Robson, R E; Li, B

    1999-08-01

    A multiterm solution of the Boltzmann equation has been developed and used to calculate transport coefficients of charged-particle swarms in gases under the influence of electric and magnetic fields crossed at arbitrary angles psi. The hierarchy resulting from a spherical harmonic decomposition of the Boltzmann equation in the hydrodynamic regime [Ness, Phys. Rev. A 47, 327 (1993)] is solved numerically by representing the speed dependence of the phase-space distribution function in terms of an expansion in Sonine polynomials about a weighted sum of Maxwellian distributions at different temperatures. Results are given for charged-particle swarms in certain model gases over a range of psi and field strengths. The variation of the transport coefficients with psi is addressed using physical arguments. The errors associated with the two-term approximation and inadequacies of Legendre polynomial expansions are highlighted.

  4. Evaluation of Hylife-II and Sombrero using 175- and 566- group neutron transport and activation cross sections

    SciTech Connect

    Cullen, D; Latkowski, J; Sanz, J

    1999-06-18

    Recent modifications to the TART Monte Carlo neutron and photon transport code enable calculation of 566-group neutron spectra. This expanded group structure represents a significant improvement over the 50- and 175-group structures that have been previously available. To support use of this new capability, neutron activation cross section libraries have been created in the 175- and 566-group structures starting from the FENDL/A-2.0 pointwise data. Neutron spectra have been calculated for the first walls of the HYLIFE-II and SOMBRERO inertial fusion energy power plant designs and have been used in subsequent neutron activation calculations. The results obtained using the two different group structures are compared to each other as well as to those obtained using a 175-group version of the EAF3.1 activation cross section library.

  5. Alternative treatment for the energy-transfer and transport cross section in dressed electron-ion binary collisions

    NASA Astrophysics Data System (ADS)

    Grande, P. L.

    2016-10-01

    A formula for determining the electronic stopping power and the transport cross section in electron-ion binary collisions is derived from the induced density for spherically symmetric potentials using the partial-wave expansion. In contrast to the previous one found in many textbooks, the present formula converges to the Bethe and Bloch stopping-power formulas at high ion velocities and agrees rather well with experimental stopping-power data, as shown here for Al, C, and H2O targets. It can be employed in plasma physics and particularly in any application that requires electronic stopping-power values of quasifree electrons with high accuracy.

  6. Transport analysis of measured neutron leakage spectra from spheres as tests of evaluated high energy cross sections

    NASA Technical Reports Server (NTRS)

    Bogart, D. D.; Shook, D. F.; Fieno, D.

    1973-01-01

    Integral tests of evaluated ENDF/B high-energy cross sections have been made by comparing measured and calculated neutron leakage flux spectra from spheres of various materials. An Am-Be (alpha,n) source was used to provide fast neutrons at the center of the test spheres of Be, CH2, Pb, Nb, Mo, Ta, and W. The absolute leakage flux spectra were measured in the energy range 0.5 to 12 MeV using a calibrated NE213 liquid scintillator neutron spectrometer. Absolute calculations of the spectra were made using version 3 ENDF/B cross sections and an S sub n discrete ordinates multigroup transport code. Generally excellent agreement was obtained for Be, CH2, Pb, and Mo, and good agreement was observed for Nb although discrepancies were observed for some energy ranges. Poor comparative results, obtained for Ta and W, are attributed to unsatisfactory nonelastic cross sections. The experimental sphere leakage flux spectra are tabulated and serve as possible benchmarks for these elements against which reevaluated cross sections may be tested.

  7. Regulation of Copper Transport Crossing Brain Barrier Systems by Cu-ATPases: Effect of Manganese Exposure

    PubMed Central

    Fu, Xue; Zhang, Yanshu; Jiang, Wendy; Monnot, Andrew Donald; Bates, Christopher Alexander; Zheng, Wei

    2014-01-01

    Regulation of cellular copper (Cu) homeostasis involves Cu-transporting ATPases (Cu-ATPases), i.e., ATP7A and ATP7B. The question as to how these Cu-ATPases in brain barrier systems transport Cu, i.e., toward brain parenchyma, cerebrospinal fluid (CSF), or blood, remained unanswered. This study was designed to characterize roles of Cu-ATPases in regulating Cu transport at the blood-brain barrier (BBB) and blood-CSF barrier (BCB) and to investigate how exposure to toxic manganese (Mn) altered the function of Cu-ATPases, thereby contributing to the etiology of Mn-induced parkinsonian disorder. Studies by quantitative real-time RT-PCR (qPCR), Western blot, and immunocytochemistry revealed that both Cu-ATPases expressed abundantly in BBB and BCB. Transport kinetic studies by in situ brain infusion and ventriculo-cisternal (VC) perfusion in Sprague Dawley rat suggested that the BBB was a major site for Cu entry into brain, whereas the BCB was a predominant route for Cu efflux from the CSF to blood. Confocal evidence showed that the presence of excess Cu or Mn in the choroid plexus cells led to ATP7A relocating toward the apical microvilli facing the CSF, but ATP7B toward the basolateral membrane facing blood. Mn exposure inhibited the production of both Cu-ATPases. Collectively, these data suggest that Cu is transported by the BBB from the blood to brain, which is mediated by ATP7A in brain capillary. By diffusion, Cu ions move from the interstitial fluid into the CSF, where they are taken up by the BCB. Within the choroidal epithelial cells, Cu ions are transported by ATP7B back to the blood. Mn exposure alters these processes, leading to Cu dyshomeostasis-associated neuronal injury. PMID:24614235

  8. Built Environment and Active Transport to School (BEATS) Study: protocol for a cross-sectional study

    PubMed Central

    Mandic, Sandra; Williams, John; Moore, Antoni; Hopkins, Debbie; Flaherty, Charlotte; Wilson, Gordon; García Bengoechea, Enrique; Spence, John C

    2016-01-01

    Introduction Active transport to school (ATS) is a convenient way to increase physical activity and undertake an environmentally sustainable travel practice. The Built Environment and Active Transport to School (BEATS) Study examines ATS in adolescents in Dunedin, New Zealand, using ecological models for active transport that account for individual, social, environmental and policy factors. The study objectives are to: (1) understand the reasons behind adolescents and their parents' choice of transport mode to school; (2) examine the interaction between the transport choices, built environment, physical activity and weight status in adolescents; and (3) identify policies that promote or hinder ATS in adolescents. Methods and analysis The study will use a mixed-method approach incorporating both quantitative (surveys, anthropometry, accelerometers, Geographic Information System (GIS) analysis, mapping) and qualitative methods (focus groups, interviews) to gather data from students, parents, teachers and school principals. The core data will include accelerometer-measured physical activity, anthropometry, GIS measures of the built environment and the use of maps indicating route to school (students)/work (parents) and perceived safe/unsafe areas along the route. To provide comprehensive data for understanding how to change the infrastructure to support ATS, the study will also examine complementary variables such as individual, family and social factors, including student and parental perceptions of walking and cycling to school, parental perceptions of different modes of transport to school, perceptions of the neighbourhood environment, route to school (students)/work (parents), perceptions of driving, use of information communication technology, reasons for choosing a particular school and student and parental physical activity habits, screen time and weight status. The study has achieved a 100% school recruitment rate (12 secondary schools). Ethics and

  9. Measurement and Correction of Cross-Plane Coupling in Transport Lines

    SciTech Connect

    Woodley, Mark D

    2000-08-23

    In future linear colliders the luminosity will depend on maintaining the small emittance aspect ratio delivered by damping rings. Correction of cross-plane coupling can be important in preventing dilution of the beam emittance. In order to minimize the vertical emittance, especially for a flat beam, it is necessary to remove all cross-plane (x-y) correlations. This paper studies emittance measurement and correction for coupled beams in the presence of realistic measurement errors. The results of simulations show that reconstruction of the full 4 x 4 beam matrix can be misleading in the presence of errors. The authors suggest more robust tuning procedures for minimizing linear coupling.

  10. 49 CFR 614.101 - Cross-reference to management systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Cross-reference to management systems. 614.101 Section 614.101 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRANSPORTATION INFRASTRUCTURE MANAGEMENT § 614.101 Cross-reference...

  11. Modeling sediment transport from an off-road vehicle trail stream crossing using WEPP model

    Treesearch

    Renee' D. Ayala; Puneet Srivastava; Christian J. Brodbeck; Emily A. Carter; Timothy P. McDonald

    2005-01-01

    There is a limited information available pertaining to the adverse effects of Off-Road-Vehicle (ORV) use and trail impacts. As a result, this study was initiated in 2003 to (a) quantify water quality impacts of an ORV trail stream crossing through monitoring of total suspended solids, and (b) conduct WEPP (Water Erosion Prediction Project) simulations to determine long...

  12. A Comparison of Faculty Dominance in U.S. and South African University Classrooms as It Relates to Cross-Cultural Relations.

    ERIC Educational Resources Information Center

    Schnell, James A.

    The South African educational system and race relations were studied in the context of effects on cross-cultural relations in the classroom. An examination of South African faculty perspectives was compared and contrasted witht U.S. faculty perspectives and was interpreted in relation to the cross-cultural relations that exist in the two…

  13. Cross-bite and oral health related quality of life in young people.

    PubMed

    Masood, Mohd; Masood, Yaghma; Newton, Tim

    2014-03-01

    This study sought to assess the impact of posterior cross-bite on OHRQoL in young people aged 15-25 and to determine whether the impact on higher domains of Oral Health Impact Profile-14 (physical disability, psychological disability, social disability and handicap) is a direct function of the cross-bite or mediated through the lower domains of OHIP-14 (functional limitation, pain and discomfort). One hundred and forty-five young adults [72 cross-bite cases and 73 controls] aged 15-25 years, attending orthodontic clinics at the Faculty of Dentistry, Universiti Teknologi MARA participated in this study. Participants completed the OHIP-14 and had a clinical examination for cross-bite. Data analyses included descriptive statistics, t-test and bivariate and multivariate regression modelling. There was no significant difference between the case and control groups in gender, age and education level. The mean scores (±SD) for OHIP-14 total and all domains were significantly higher in cross-bite patients as compared to controls. The bivariate and multivariate regression analyses showed functional limitation was significantly associated with all the higher domains in all four models, whereas pain was only significantly associated with the psychological domain and discomfort was only significantly associated with the physical disability domain. The possession of a posterior cross bite has a significant association with OHRQoL especially on the functional limitation and psychological disability domains, among 15-25 years old young people. The relationship of cross-bite and lower domains of OHIP-14 with higher domains of OHIP-14 was in agreement with the relationships proposed by Locker's conceptual model of oral health. Patients with a cross bite were more limited in their oral functions and experienced greater psychological discomfort than did controls. It is possible that part of patients' rationale for seeking treatment would be to alleviate such impacts on their oral

  14. Patterns of adult cross-racial friendships: A context for understanding contemporary race relations.

    PubMed

    Plummer, Deborah L; Stone, Rosalie Torres; Powell, Lauren; Allison, Jeroan

    2016-10-01

    This study examined patterns, characteristics, and predictors of cross-racial friendships as the context for understanding contemporary race relations. A national survey included 1,055 respondents, of whom 55% were white, 32% were black, and 74% were female; ages ranged from 18 to ≥65 years. Focus groups were conducted to assess societal and personal benefits. Participants (n = 31) were racially diverse and aged 20 to 66 years. After accounting for multiple covariates, regression analysis revealed that Asians, Hispanics, and multiracial individuals are more likely than their white and black counterparts to have cross-racial friends. Females were less likely than males to have 8 or more cross-racial friends. Regression analysis revealed that the depth of cross-racial friendships was greater for women than men and for those who shared more life experiences. Increasing age was associated with lower cross-racial friendship depth. Qualitative analysis of open-ended questions and focus group data established the social context as directly relevant to the number and depth of friendships. Despite the level of depth in cross-racial friendships, respondents described a general reluctance to discuss any racially charged societal events, such as police shootings of unarmed black men. This study identified salient characteristics of individuals associated with cross-racial friendships and highlighted the influence of the social, historical, and political context in shaping such friendships. Our findings suggest that contemporary race relations reflect progress as well as polarization. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  15. Evaluating the role of carbonic anhydrases in the transport of HCO3−-related species

    PubMed Central

    Boron, Walter F.

    2015-01-01

    The soluble enzyme carbonic anhydrase II (CAII) plays an important role in CO2 influx and efflux by red blood cells (RBCs), a process initiated by changes in the extracellular [CO2] (CO2-initiated CO2 transport). Evidence suggests that CAII may be part of a macromolecular complex at the inner surface of the RBC membrane. Some have suggested CAII specifically binds to a motif on the cytoplasmic C terminus (Ct) of the Cl–HCO3 exchanger AE1 and some other members of the SLC4 family of HCO3− transporters, a transport metabolon. Moreover, others have suggested that this bound CAII enhances the transport of HCO3−-related species—HCO3−, CO3=, or CO3= ion pairs—when the process is initiated by altering the activity of the transporter (HCO3−-initiated HCO3− transport). In this review, I assess the theoretical roles of CAs in the transport of CO2 and HCO3−-related species, concluding that although the effect of bound CAII on CO2-initiated CO2 transport is expected to be substantial, the effect of bound CAs on HCO3−-initiated HCO3− transport is expected to be modest at best. I also assess the experimental evidence for CAII binding to AE1 and other transporters, and the effects of this binding on HCO3−-initiated HCO3− transport. The early conclusion that CAII binds to the Ct of AE1 appears to be the result of unpredictable effects of GST in the GST fusion proteins used in the studies. The early conclusion that bound CAII speeds HCO3−-initiated HCO3− transport appears to be the result of CAII accelerating the pH changes used as a read-out of transport. Thus, it appears that CAII does not bind directly to AE1 or other SLC4 proteins, and that bound CAII does not substantially accelerate HCO3−-initiated HCO3− transport. PMID:19879980

  16. Review of Transporter-Related Postmarketing Requirement or Postmarketing Commitment Studies.

    PubMed

    Fan, Ying; Sun, Bo; Agarwal, Sheetal; Zhang, Lei

    2016-07-01

    The objectives of this report are to summarize the content and status of transporter-related postmarketing requirement (PMR)/postmarketing commitment (PMC) studies in new drug applications (NDAs) approved by the U.S. Food and Drug Administration (FDA) and to discuss the reasons for requesting such studies and the impact of PMR/PMC study results on labeling to guide the optimal use of the drugs. Multiple data sources were searched to collect information on transporter-related PMR/PMC studies between January 1999 and May 2015. A total of 40 transporter-related PMR/PMC study requests were issued for 35 NDAs. Among these PMR/PMC studies, 27 requested studies related to P-glycoprotein. As of May 31, 2015, 34 transporter-related PMR/PMC studies (85%) are considered "fulfilled" (per the FDA's PMR/PMC website), and 22 (65%) resulted in labeling updates. The majority of the PMR/PMC studies are for drugs in the therapeutic areas of anti-infectives, oncology, and neurology. The results from PMR/PMC studies are important for dosing optimization and are often included in the updated labeling. Because a significant lag time is anticipated between drug approval and PMR/PMC fulfillment, NDA applicants are encouraged to include transporter-related assessments in clinical drug development programs for drug products.

  17. Built Environment and Active Transport to School (BEATS) Study: protocol for a cross-sectional study.

    PubMed

    Mandic, Sandra; Williams, John; Moore, Antoni; Hopkins, Debbie; Flaherty, Charlotte; Wilson, Gordon; García Bengoechea, Enrique; Spence, John C

    2016-05-24

    Active transport to school (ATS) is a convenient way to increase physical activity and undertake an environmentally sustainable travel practice. The Built Environment and Active Transport to School (BEATS) Study examines ATS in adolescents in Dunedin, New Zealand, using ecological models for active transport that account for individual, social, environmental and policy factors. The study objectives are to: (1) understand the reasons behind adolescents and their parents' choice of transport mode to school; (2) examine the interaction between the transport choices, built environment, physical activity and weight status in adolescents; and (3) identify policies that promote or hinder ATS in adolescents. The study will use a mixed-method approach incorporating both quantitative (surveys, anthropometry, accelerometers, Geographic Information System (GIS) analysis, mapping) and qualitative methods (focus groups, interviews) to gather data from students, parents, teachers and school principals. The core data will include accelerometer-measured physical activity, anthropometry, GIS measures of the built environment and the use of maps indicating route to school (students)/work (parents) and perceived safe/unsafe areas along the route. To provide comprehensive data for understanding how to change the infrastructure to support ATS, the study will also examine complementary variables such as individual, family and social factors, including student and parental perceptions of walking and cycling to school, parental perceptions of different modes of transport to school, perceptions of the neighbourhood environment, route to school (students)/work (parents), perceptions of driving, use of information communication technology, reasons for choosing a particular school and student and parental physical activity habits, screen time and weight status. The study has achieved a 100% school recruitment rate (12 secondary schools). The study has been approved by the University of Otago

  18. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS... and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating to transportation of hazardous and nuclear waste? Sections 170.900 through 170.907 on transportation of nuclear...

  19. Gravity-Related Transport Process in Off-Axis Sputtering Deposition

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Su, Ching-Hua; Lehozeku, S. L.

    2000-01-01

    In the synthesis of epitaxial oxide films, reactive off-axis sputtering deposition techniques have demonstrated the advantages of fabricating high quality epitaxial films. Due to the collisions between the sputtered species and the residue gases, the kinetic energy of species was reduced and the transport of depositing species changed from a ballistic movement to a diffusive drift in which the transport species were almost thermalized. A gravity effect could appear in the transport process. Three transport regimes were observed when the growth pressures vary from 5 mTorr to 150 mTorr. Film growth rate, depositing orientations, crystal structure, surface morphology, and compositions were characterized. A gravity related phenomenon was revealed in film growth at the relative low growth pressures.

  20. Gravity-Related Transport Process in Off-Axis Sputtering Deposition

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Su, Ching-Hua; Lehozeku, S. L.

    2000-01-01

    In the synthesis of epitaxial oxide films, reactive off-axis sputtering deposition techniques have demonstrated the advantages of fabricating high quality epitaxial films. Due to the collisions between the sputtered species and the residue gases, the kinetic energy of species was reduced and the transport of depositing species changed from a ballistic movement to a diffusive drift in which the transport species were almost thermalized. A gravity effect could appear in the transport process. Three transport regimes were observed when the growth pressures vary from 5 mTorr to 150 mTorr. Film growth rate, depositing orientations, crystal structure, surface morphology, and compositions were characterized. A gravity related phenomenon was revealed in film growth at the relative low growth pressures.

  1. The Safety Related Software for Railway Control with Respect to Automatic Level Crossing Signaling System

    NASA Astrophysics Data System (ADS)

    Lewiński, Andrzej; Trzaska-Rycaj, Katarzyna

    The paper deals with design problems of correct and high reliable software for railway traffic control systems. The correct software (corresponding to formal or semi-formal criteria) has an important part in safety related (SIL4) railway control systems. The paper treats about actual state of art in design of safety related software for railway application. The proposed methods, recommended by CENELEC and UIC are introduced to example of automatic level crossing signaling system.

  2. Comparative stress responses to short transport and related events in Hereford and Brahman steers.

    PubMed

    Browning, R; Leite-Browning, M L

    2013-02-01

    Three summer experiments compared responses to transportation-related events in 2- to 4-yr-old Brahman (Bos indicus) and Hereford (B. taurus) steers. In Exp. 1, steers were hauled round-trip (4 h) or fasted in holding pens. Transport transiently increased (P < 0.01) plasma cortisol and glucose concentrations, decreased (P < 0.05) plasma triglyceride concentrations, and increased total leukocyte counts. Blood constituents were not altered for steers fasting in holding pens. Treatment-day BW shrink was greater (P < 0.01) in transported steers than penned steers. Blood constituent responses were unaffected (P < 0.05) by subspecies. Hereford experienced greater (P < 0.05) transport-day BW shrink than Brahman across treatments. Steers in Exp. 2 were hauled to a new farm for a 1-wk relocation period or hauled round-trip an equal time (0.67 h) and returned to the home station. Both treatments similarly experienced transport-day BW shrink and increased (P < 0.01) plasma cortisol and glucose. Subspecies did not affect (P < 0.05) blood constituent responses to transport. Hereford experienced greater (P < 0.05) transport-day shrink than Brahman. Relocation did not elicit (P < 0.05) changes in blood profiles beyond the day of transport. In Exp. 3, steers were loaded and unloaded without transport, transported round-trip (1 h), or fasted in a holding pen for 3 h. Cortisol increased (P < 0.01) after transport and after loading/unloading. Leukocytes and glucose increased (P < 0.01) after the 1 h transport. Steers transported experienced greater treatment-day BW shrink than those fasted or loaded and unloaded (P < 0.01; -3.13 vs. -1.36 and -0.35 ± 0.76%, respectively). The subspecies did not vary (P < 0.05) for blood constituent responses or shrink in Exp. 3. Animal responses were not evident 24 h after treatments in each experiment. In summary, transport caused stress, but Brahman steers were not more sensitive than Herefords. Hereford steers were susceptible to greater

  3. Effective Potential Energies and Transport Cross Sections for Atom-Molecule Interactions of Nitrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, Jim (Technical Monitor)

    2001-01-01

    The potential energy surfaces for H2-N and N2-N interactions are calculated by accurate ab initio methods and applied to determine transport data. The results confirm that an effective potential energy for accurately determining transport properties can be calculated using a single orientation. A simple method is developed to determine the dispersion coefficients of effective potential energies Effective potential energies required for O2-O collisions are determ=ined. The H2-N, N2-N, O2-H, and O2-O collision integrals are calculated and tabulated for a large range of temperatures. The theoretical values of the N2-N and O2-O diffusion coefficients compare well with measured data available at room temperature.

  4. Crossed fiber optic Bessel beams for curvilinear optofluidic transport of dielectric particles.

    PubMed

    Kim, Jongki; Lee, Sungrae; Jeong, Yoonseob; Kim, Jun-Ki; Jung, Yongmin; Merenda, Fabrice; Salathè, Renè-Paul; Shin, Jeon-Soo; Oh, Kyunghwan

    2013-10-07

    Due to its unique non-diffracting and self-reconstructing nature, Bessel beams have been successfully adopted to trap multiple particles along the beam's axial direction. However, prior bulk-optic based Bessel beams have a fundamental form-factor limitation for in situ, in-vitro, and in-vivo applications. Here we present a novel implementation of Fourier optics along a single strand of hybrid optical fiber in a monolithic manner that can generate pseudo Bessel beam arrays in two-dimensional space. We successfully demonstrate unique optofluidic transport of the trapped dielectric particles along a curvilinear optical route by multiplexing the fiber optic pseudo Bessel beams. The proposed technique can form a new building block to realize reconfigurable optofluidic transportation of particulates that can break the limitations of both prior bulk-optic Bessel beam generation techniques and conventional microfluidic channels.

  5. Effective Potential Energies and Transport Cross Sections for Atom-Molecule Interactions of Nitrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, Jim (Technical Monitor)

    2001-01-01

    The potential energy surfaces for H2-N and N2-N interactions are calculated by accurate ab initio methods and applied to determine transport data. The results confirm that an effective potential energy for accurately determining transport properties can be calculated using a single orientation. A simple method is developed to determine the dispersion coefficients of effective potential energies Effective potential energies required for O2-O collisions are determ=ined. The H2-N, N2-N, O2-H, and O2-O collision integrals are calculated and tabulated for a large range of temperatures. The theoretical values of the N2-N and O2-O diffusion coefficients compare well with measured data available at room temperature.

  6. Cross-tolerance and cross-talk in the cold: relating low temperatures to desiccation and immune stress in insects.

    PubMed

    Sinclair, Brent J; Ferguson, Laura V; Salehipour-shirazi, Golnaz; MacMillan, Heath A

    2013-10-01

    Multiple stressors, both abiotic and biotic, often are experienced simultaneously by organisms in nature. Responses to these stressors may share signaling pathways ("cross-talk") or protective mechanisms ("cross-tolerance"). Temperate and polar insects that must survive the winter experience low temperatures accompanied by additional abiotic stressors, such as low availability of water. Cold and desiccation have many similar effects at a cellular level, and we present evidence that the cellular mechanisms that protect against cold stress also protect against desiccation, and that the responses to cold and dehydration likely evolved as cross-tolerance. By contrast, there are several lines of evidence suggesting that low temperature stress elicits an upregulation of immune responses in insects (and vice versa). Because there is little mechanistic overlap between cold stress and immune stress at the cellular level, we suggest that this is cross-talk. Both cross-talk and cross-tolerance may be adaptive and likely evolved in response to synchronous stressors; however, we suggest that cross-talk and cross-tolerance may lead to different responses to changes in the timing and severity of multiple stress interactions in a changing world. We present a framework describing the potentially different responses of cross-tolerance and cross-talk to a changing environment and describe the nature of these impacts using interaction of cold-desiccation and cold-immunity in overwintering insects as an example.

  7. The role of cross-shock potential on pickup ion shock acceleration in the framework of focused transport theory

    SciTech Connect

    Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K.

    2013-10-03

    The focused transport theory is appropriate to describe the injection and acceleration of low-energy particles at shocks as an extension of diffusive shock acceleration (DSA). In this investigation, we aim to characterize the role of cross-shock potential (CSP) originated in the charge separation across the shock ramp on pickup ion (PUI) acceleration at various types of shocks with a focused transport model. The simulation results of energy spectrum and spatial density distribution for the cases with and without CSP added in the model are compared. With sufficient acceleration time, the focused transport acceleration finally falls into the DSA regime with the power-law spectral index equal to the solution of the DSA theory. The CSP can affect the shape of the spectrum segment at lower energies, but it does not change the spectral index of the final power-law spectrum at high energies. It is found that the CSP controls the injection efficiency which is the fraction of PUIs reaching the DSA regime. A stronger CSP jump results in a dramatically improved injection efficiency. Our simulation results also show that the injection efficiency of PUIs is mass-dependent, which is lower for species with a higher mass. Additionally, the CSP is able to enhance the particle reflection upstream to produce a stronger intensity spike at the shock front. Lastly, we conclude that the CSP is a non-negligible factor that affects the dynamics of PUIs at shocks.

  8. The role of cross-shock potential on pickup ion shock acceleration in the framework of focused transport theory

    DOE PAGES

    Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K.

    2013-10-03

    The focused transport theory is appropriate to describe the injection and acceleration of low-energy particles at shocks as an extension of diffusive shock acceleration (DSA). In this investigation, we aim to characterize the role of cross-shock potential (CSP) originated in the charge separation across the shock ramp on pickup ion (PUI) acceleration at various types of shocks with a focused transport model. The simulation results of energy spectrum and spatial density distribution for the cases with and without CSP added in the model are compared. With sufficient acceleration time, the focused transport acceleration finally falls into the DSA regime withmore » the power-law spectral index equal to the solution of the DSA theory. The CSP can affect the shape of the spectrum segment at lower energies, but it does not change the spectral index of the final power-law spectrum at high energies. It is found that the CSP controls the injection efficiency which is the fraction of PUIs reaching the DSA regime. A stronger CSP jump results in a dramatically improved injection efficiency. Our simulation results also show that the injection efficiency of PUIs is mass-dependent, which is lower for species with a higher mass. Additionally, the CSP is able to enhance the particle reflection upstream to produce a stronger intensity spike at the shock front. Lastly, we conclude that the CSP is a non-negligible factor that affects the dynamics of PUIs at shocks.« less

  9. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Prohibited transportation-related transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SUDANESE...

  10. 76 FR 52731 - On-Line Complaint Form for Service-Related Issues in Air Transportation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... Office of the Secretary On-Line Complaint Form for Service-Related Issues in Air Transportation AGENCY... public to electronically submit aviation service-related complaints against air carriers. DATES: Comments... U.S.C., Subtitle VII, to investigate and enforce consumer protection and civil rights laws...

  11. 78 FR 24159 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... List and U.S. export control policies shall be exempt from the provisions relating to public meetings... Secretary for Export Administration with respect to technical questions that affect the level of export controls applicable to transportation and related equipment or technology. Agenda Public Session 1. Welcome...

  12. Serological cross-reactivity between Merkel cell polyomavirus and two closely related chimpanzee polyomaviruses.

    PubMed

    Nicol, Jérôme T J; Liais, Etienne; Potier, Romain; Mazzoni, Elisa; Tognon, Mauro; Coursaget, Pierre; Touzé, Antoine

    2014-01-01

    Phylogenetic analyses based on the major capsid protein sequence indicate that Merkel cell polyomavirus (MCPyV) and chimpanzee polyomaviruses (PtvPyV1, PtvPyV2), and similarly Trichodysplasia spinulosa-associated polyomavirus (TSPyV) and the orangutan polyomavirus (OraPyV1) are closely related. The existence of cross-reactivity between these polyomaviruses was therefore investigated. The findings indicated serological identity between the two chimpanzee polyomaviruses investigated and a high level of cross-reactivity with Merkel cell polyomavirus. In contrast, cross-reactivity was not observed between TSPyV and OraPyV1. Furthermore, specific antibodies to chimpanzee polyomaviruses were detected in chimpanzee sera by pre-incubation of sera with the different antigens, but not in human sera.

  13. Threshold crossing of device-based intrathoracic impedance trends identifies relatively increased mortality risk.

    PubMed

    Tang, Wai Hong Wilson; Warman, Eduardo N; Johnson, James W; Small, Roy S; Heywood, James Thomas

    2012-09-01

    Threshold crossings of impedance trends detected by implanted devices have been associated with clinically relevant heart failure events, but long-term prognosis of such events has not been demonstrated. The aim of this study is to examine the relationship between alterations in intrathoracic impedance and mortality risk in patients with implantable devices. We reviewed remote monitoring data in the de-identified Medtronic CareLink(®) Discovery Link that captured intrathoracic impedance trends for >6 months. The initial 6 months of the cardiac and impedance trends were used as the observation period to create the patient groups and cross-referenced with the Social Security Death Index for mortality data. In our study cohort of 21 217 patients, 36% experienced impedance threshold crossing within the initial 6 months of monitoring (defined as the 'early threshold crossing' group). Patients with early threshold crossings demonstrated an increased risk of age- and gender-adjusted all-cause mortality [hazard ratio (HR) 2.15, 95% confidence interval (CI) 1.95-2.38, P< 0.0001]. Increased mortality risk remained significant when analysed in subgroups of patients without defibrillator shock (HR 2.10, 95% CI 1.90-2.34, P< 0.0001, n= 1621) or within those patients without device-detectable atrial fibrillation (AF) during the initial 6 months of monitoring (HR 2.09, 95% CI 1.86-2.34, P< 0.0001, n= 17 235). Both the number and the duration of early threshold crossings of impedance trends detectable by implanted devices were associated with increased mortality risk. Furthermore, the improvement of altered impedance trends portends more favourable prognosis. Threshold crossing of impedance trends detectable by implanted devices is associated with relatively increased mortality risk even after adjusted for demographic, device-detected AF, or defibrillator shocks.

  14. Cross-Fostering Differentially Affects ADHD-Related Behaviors in Spontaneously Hypertensive Rats

    PubMed Central

    Gauthier, Angela C.; DeAngeli, Nicole E.; Bucci, David J.

    2014-01-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain. PMID:25647439

  15. Assessment of the transport routes of oversized and excessive loads in relation to the passage through roundabout

    NASA Astrophysics Data System (ADS)

    Petru, Jan; Dolezel, Jiri; Krivda, Vladislav

    2017-09-01

    In the past the excessive and oversized loads were realized on selected routes on roads that were adapted to ensure smooth passage of transport. Over the years, keeping the passages was abandoned and currently there are no earmarked routes which would be adapted for such type of transportation. The routes of excessive and oversized loads are currently planned to ensure passage of the vehicle through the critical points on the roads. Critical points are level and fly-over crossings of roads, bridges, toll gates, traffic signs and electrical and other lines. The article deals with the probability assessment of selected critical points of the route of the excessive load on the roads of 1st class, in relation to ensuring the passage through the roundabout. The bases for assessing the passage of the vehicle with excessive load through a roundabout are long-term results of video analyses of monitoring the movement of transports on similar intersections and determination of the theoretical probability model of vehicle movement at selected junctions. On the basis of a virtual simulation of the vehicle movement at crossroads and using MonteCarlo simulation method vehicles’ paths are analysed and the probability of exit of the vehicle outside the crossroad in given junctions is quantified.

  16. COHeRE: Cross-Ontology Hierarchical Relation Examination for Ontology Quality Assurance.

    PubMed

    Cui, Licong

    Biomedical ontologies play a vital role in healthcare information management, data integration, and decision support. Ontology quality assurance (OQA) is an indispensable part of the ontology engineering cycle. Most existing OQA methods are based on the knowledge provided within the targeted ontology. This paper proposes a novel cross-ontology analysis method, Cross-Ontology Hierarchical Relation Examination (COHeRE), to detect inconsistencies and possible errors in hierarchical relations across multiple ontologies. COHeRE leverages the Unified Medical Language System (UMLS) knowledge source and the MapReduce cloud computing technique for systematic, large-scale ontology quality assurance work. COHeRE consists of three main steps with the UMLS concepts and relations as the input. First, the relations claimed in source vocabularies are filtered and aggregated for each pair of concepts. Second, inconsistent relations are detected if a concept pair is related by different types of relations in different source vocabularies. Finally, the uncovered inconsistent relations are voted according to their number of occurrences across different source vocabularies. The voting result together with the inconsistent relations serve as the output of COHeRE for possible ontological change. The highest votes provide initial suggestion on how such inconsistencies might be fixed. In UMLS, 138,987 concept pairs were found to have inconsistent relationships across multiple source vocabularies. 40 inconsistent concept pairs involving hierarchical relationships were randomly selected and manually reviewed by a human expert. 95.8% of the inconsistent relations involved in these concept pairs indeed exist in their source vocabularies rather than being introduced by mistake in the UMLS integration process. 73.7% of the concept pairs with suggested relationship were agreed by the human expert. The effectiveness of COHeRE indicates that UMLS provides a promising environment to enhance

  17. COHeRE: Cross-Ontology Hierarchical Relation Examination for Ontology Quality Assurance

    PubMed Central

    Cui, Licong

    2015-01-01

    Biomedical ontologies play a vital role in healthcare information management, data integration, and decision support. Ontology quality assurance (OQA) is an indispensable part of the ontology engineering cycle. Most existing OQA methods are based on the knowledge provided within the targeted ontology. This paper proposes a novel cross-ontology analysis method, Cross-Ontology Hierarchical Relation Examination (COHeRE), to detect inconsistencies and possible errors in hierarchical relations across multiple ontologies. COHeRE leverages the Unified Medical Language System (UMLS) knowledge source and the MapReduce cloud computing technique for systematic, large-scale ontology quality assurance work. COHeRE consists of three main steps with the UMLS concepts and relations as the input. First, the relations claimed in source vocabularies are filtered and aggregated for each pair of concepts. Second, inconsistent relations are detected if a concept pair is related by different types of relations in different source vocabularies. Finally, the uncovered inconsistent relations are voted according to their number of occurrences across different source vocabularies. The voting result together with the inconsistent relations serve as the output of COHeRE for possible ontological change. The highest votes provide initial suggestion on how such inconsistencies might be fixed. In UMLS, 138,987 concept pairs were found to have inconsistent relationships across multiple source vocabularies. 40 inconsistent concept pairs involving hierarchical relationships were randomly selected and manually reviewed by a human expert. 95.8% of the inconsistent relations involved in these concept pairs indeed exist in their source vocabularies rather than being introduced by mistake in the UMLS integration process. 73.7% of the concept pairs with suggested relationship were agreed by the human expert. The effectiveness of COHeRE indicates that UMLS provides a promising environment to enhance

  18. The taste-visual cross-modal Stroop effect: An event-related brain potential study.

    PubMed

    Xiao, X; Dupuis-Roy, N; Yang, X L; Qiu, J F; Zhang, Q L

    2014-03-28

    Event-related potentials (ERPs) were recorded to explore, for the first time, the electrophysiological correlates of the taste-visual cross-modal Stroop effect. Eighteen healthy participants were presented with a taste stimulus and a food image, and asked to categorize the image as "sweet" or "sour" by pressing the relevant button as quickly as possible. Accurate categorization of the image was faster when it was presented with a congruent taste stimulus (e.g., sour taste/image of lemon) than with an incongruent one (e.g., sour taste/image of ice cream). ERP analyses revealed a negative difference component (ND430-620) between 430 and 620ms in the taste-visual cross-modal Stroop interference. Dipole source analysis of the difference wave (incongruent minus congruent) indicated that two generators localized in the prefrontal cortex and the parahippocampal gyrus contributed to this taste-visual cross-modal Stroop effect. This result suggests that the prefrontal cortex is associated with the process of conflict control in the taste-visual cross-modal Stroop effect. Also, we speculate that the parahippocampal gyrus is associated with the process of discordant information in the taste-visual cross-modal Stroop effect.

  19. A cross-cultural comparison of the coexistence and domain superiority of individuating and relating autonomy.

    PubMed

    Yeh, Kuang-Hui; Bedford, Olwen; Yang, Yung-Jui

    2009-06-01

    The consensus definition of autonomy in the psychological literature emphasizes self-governance through free volition, not separation or independence from others. Since the concept of self may differ cross-culturally, several researchers have tried to incorporate types of self into the notion of autonomy; however, only the dual model of autonomy has been able to do this while retaining an emphasis on volition. The dual model describes two distinct forms of autonomy-individuating and relating-each with superior function in a specific domain of individual functioning. Individuating autonomy represents a volitional capacity to act against social constraints and offers a route to achieve an independent self-identity by expressing individualistic attributes and distinctions. Relating autonomy represents a volitional capacity to act by emphasizing the harmony of self-in-relation-to-others, the quality of interpersonal relationships, and self-transcendence. These two forms of autonomy have been shown to coexist at the individual level in a Taiwanese sample. This study takes the next step, with a cross-cultural test of the coexistence and domain superiority hypotheses of individuating and relating autonomy. Participants included 306 college students from Taiwan and 183 college students from the United States. Structural equation modelling by multigroup analyses confirmed the cross-cultural equivalence of the two-factor individuating autonomy and relating autonomy measurement model. Across both samples the two forms of autonomy were shown to be mutually inclusive and not exclusive or independent. The domain-superior function of each form of autonomy was also confirmed cross-culturally; each form of autonomy has a dominant, but not necessarily exclusive, domain of functioning. Specifically, individuating autonomy was more associated with intrapersonal than interpersonal domain dependent variables, while relating autonomy was more associated with interpersonal than

  20. Robust transport by multiple motors with nonlinear force-velocity relations and stochastic load sharing

    NASA Astrophysics Data System (ADS)

    Kunwar, Ambarish; Mogilner, Alexander

    2010-03-01

    Transport by processive molecular motors plays an important role in many cell biological phenomena. In many cases, motors work together to transport cargos in the cell, so it is important to understand the mechanics of the multiple motors. Based on earlier modeling efforts, here we study effects of nonlinear force-velocity relations and stochastic load sharing on multiple motor transport. We find that when two or three motors transport the cargo, then the nonlinear and stochastic effects compensate so that the mechanical properties of the transport are robust. Similarly, the transport is insensitive to compliance of the cargo-motor links. Furthermore, the rate of movement against moderate loads is not improved by increasing the small number of motors. When the motor number is greater than 4, correlations between the motors become negligible, and the earlier analytical mean-field theory of the multiple motor transport holds. We predict that the effective diffusion of the cargo driven by the multiple motors under load increases by an order of magnitude compared to that for the single motor. Finally, our simulations predict that the stochastic effects are responsible for a significant dispersion of velocities generated by the 'tug-of-war' of the multiple opposing motors.

  1. Quantifying the relative contributions of different solute carriers to aggregate substrate transport

    PubMed Central

    Taslimifar, Mehdi; Oparija, Lalita; Verrey, Francois; Kurtcuoglu, Vartan; Olgac, Ufuk; Makrides, Victoria

    2017-01-01

    Determining the contributions of different transporter species to overall cellular transport is fundamental for understanding the physiological regulation of solutes. We calculated the relative activities of Solute Carrier (SLC) transporters using the Michaelis-Menten equation and global fitting to estimate the normalized maximum transport rate for each transporter (Vmax). Data input were the normalized measured uptake of the essential neutral amino acid (AA) L-leucine (Leu) from concentration-dependence assays performed using Xenopus laevis oocytes. Our methodology was verified by calculating Leu and L-phenylalanine (Phe) data in the presence of competitive substrates and/or inhibitors. Among 9 potentially expressed endogenous X. laevis oocyte Leu transporter species, activities of only the uniporters SLC43A2/LAT4 (and/or SLC43A1/LAT3) and the sodium symporter SLC6A19/B0AT1 were required to account for total uptake. Furthermore, Leu and Phe uptake by heterologously expressed human SLC6A14/ATB0,+ and SLC43A2/LAT4 was accurately calculated. This versatile systems biology approach is useful for analyses where the kinetics of each active protein species can be represented by the Hill equation. Furthermore, its applicable even in the absence of protein expression data. It could potentially be applied, for example, to quantify drug transporter activities in target cells to improve specificity. PMID:28091567

  2. Robust transport by multiple motors with nonlinear force-velocity relations and stochastic load sharing.

    PubMed

    Kunwar, Ambarish; Mogilner, Alexander

    2010-02-10

    Transport by processive molecular motors plays an important role in many cell biological phenomena. In many cases, motors work together to transport cargos in the cell, so it is important to understand the mechanics of the multiple motors. Based on earlier modeling efforts, here we study effects of nonlinear force-velocity relations and stochastic load sharing on multiple motor transport. We find that when two or three motors transport the cargo, then the nonlinear and stochastic effects compensate so that the mechanical properties of the transport are robust. Similarly, the transport is insensitive to compliance of the cargo-motor links. Furthermore, the rate of movement against moderate loads is not improved by increasing the small number of motors. When the motor number is greater than 4, correlations between the motors become negligible, and the earlier analytical mean-field theory of the multiple motor transport holds. We predict that the effective diffusion of the cargo driven by the multiple motors under load increases by an order of magnitude compared to that for the single motor. Finally, our simulations predict that the stochastic effects are responsible for a significant dispersion of velocities generated by the 'tug-of-war' of the multiple opposing motors.

  3. Robust transport by multiple motors with nonlinear force–velocity relations and stochastic load sharing

    PubMed Central

    Kunwar, Ambarish; Mogilner, Alexander

    2010-01-01

    Transport by processive molecular motors plays an important role in many cell biological phenomena. In many cases, motors work together to transport cargos in the cell, so it is important to understand the mechanics of the multiple motors. Based on earlier modeling efforts, here we study effects of nonlinear force–velocity relations and stochastic load sharing on multiple motor transport. We find that when two or three motors transport the cargo, then the nonlinear and stochastic effects compensate so that the mechanical properties of the transport are robust. Similarly, the transport is insensitive to compliance of the cargo-motor links. Furthermore, the rate of movement against moderate loads is not improved by increasing the small number of motors. When the motor number is greater than 4, correlations between the motors become negligible, and the earlier analytical mean-field theory of the multiple motor transport holds. We predict that the effective diffusion of the cargo driven by the multiple motors under load increases by an order of magnitude compared to that for the single motor. Finally, our simulations predict that the stochastic effects are responsible for a significant dispersion of velocities generated by the ‘tug-of-war’ of the multiple opposing motors. PMID:20147778

  4. Axonal transport declines with age in two distinct phases separated by a period of relative stability☆

    PubMed Central

    Milde, Stefan; Adalbert, Robert; Elaman, M. Handan; Coleman, Michael P.

    2015-01-01

    Axonal transport is critical for supplying newly synthesized proteins, organelles, mRNAs, and other cargoes from neuronal cell bodies into axons. Its impairment in many neurodegenerative conditions appears likely to contribute to pathogenesis. Axonal transport also declines during normal aging, but little is known about the timing of these changes, or about the effect of aging on specific cargoes in individual axons. This is important for understanding mechanisms of age-related axon loss and age-related axonal disorders. Here we use fluorescence live imaging of peripheral nerve and central nervous system tissue explants to investigate vesicular and mitochondrial axonal transport. Interestingly, we identify 2 distinct periods of change, 1 period during young adulthood and the other in old age, separated by a relatively stable plateau during most of adult life. We also find that after tibial nerve regeneration, even in old animals, neurons are able to support higher transport rates of each cargo for a prolonged period. Thus, the age-related decline in axonal transport is not an inevitable consequence of either aging neurons or an aging systemic milieu. PMID:25443288

  5. Environmental impact assessment in urban transport planning: Exploring process-related barriers in Spanish practice

    SciTech Connect

    Soria-Lara, Julio A. Bertolini, Luca Brömmelstroet, Marco te

    2015-01-15

    The effectiveness of EIA for evaluating transport planning projects is increasingly being questioned by practitioners, institutions and scholars. The academic literature has traditionally focused more on solving content-related problems with EIA (i.e. the measurement of environmental effects) than on process-related issues (i.e. the role of EIA in the planning process and the interaction between key actors). Focusing only on technical improvements is not sufficient for rectifying the effectiveness problems of EIA. In order to address this knowledge gap, the paper explores how EIA is experienced in the Spanish planning context and offers in-depth insight into EIA process-related issues in the field of urban transport planning. From the multitude of involved actors, the research focuses on exploring the perceptions of the two main professional groups: EIA developers and transport planners. Through a web-based survey we assess the importance of process-related barriers to the effective use of EIA in urban transport planning. The analyses revealed process issues based fundamentally on unstructured stakeholders involvement and an inefficient public participation - Highlights: • Qualitative research on perceptions of EIA participants on EIA processes. • Web-based survey with different participants (EIA-developers; transport planners). • It was seen an inefficient participation of stakeholders during the EIA processes.

  6. 41 CFR 102-117.95 - What transportation documents must I use to acquire freight, household goods or other related...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... documents must I use to acquire freight, household goods or other related transportation services? 102-117... acquire freight, household goods or other related transportation services? (a) Bills of lading and purchase orders are the transportation documents you use to acquire freight, household goods shipments,...

  7. 41 CFR 301-72.100 - What must my travel accounting system do in relation to common carrier transportation?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... accounting system do in relation to common carrier transportation? 301-72.100 Section 301-72.100 Public... for Common Carrier Transportation § 301-72.100 What must my travel accounting system do in relation to... claims accounting systems with common carrier transportation documents and data for audit purposes; (c...

  8. Electrowetting actuated microfluidic transport in surface grooves with triangular cross section.

    PubMed

    Barman, Jitesh; Swain, Digendranath; Law, Bruce M; Seemann, Ralf; Herminghaus, Stephan; Khare, Krishnacharya

    2015-01-27

    Liquids show different static wetting morphologies in open triangular grooves depending upon the wedge angle (ψ) of the groove and the liquid contact angle (θ) with the substrate. Switching between different morphologies can be achieved either by varying the contact angle of the liquid or by changing the wedge angle of the groove. In the present work we manipulate the apparent contact angle of a liquid by electrowetting to switch between liquid morphologies, from droplet to filament, to achieve microfluidic transport of the liquid into open triangular grooves. The static length of liquid filaments in grooves is analyzed as a function of applied voltage for different applied ac frequencies. The dynamic advancement of the filament lengths in grooves is analyzed as a function of time for different applied voltages for two different liquids: first with contact angle greater than the wedge angle and second with contact angle smaller than the wedge angle. Later an exact electrical model is derived to explain the liquid transport in triangular grooves actuated by electrowetting which includes the precise geometry of the liquid morphology.

  9. Cross-Cultural Perspectives of Service Quality and Risk in Air Transportation

    NASA Technical Reports Server (NTRS)

    Cunningham, Lawrence F.; Young, Clifford E.; Lee, Moonkyu

    2002-01-01

    This study compares US and Korean customers in terms of their perceptions of airline service quality based on SERVPERF and industry-based measures, as well as their perceptions of risks involved in the airline choice. SERVPERF is a set of multi-dimensional measures of customer evaluations of service quality. The results indicate that: (1) US passengers are generally more satisfied with their airline service than Korean customers on most of the SERVPERF dimensions; (2) Koreans are generally more satisfied with the bumping procedures whereas US participants feel more satisfied with the airline's baggage handling, operations/safety, and connections; and (3) US participants perceive higher levels of performance and financial risks whereas Koreans feel greater social risk in choosing an airline. This study also examines the SERVPERF, industry-based measure, and perceived risk in predicting customer satisfaction with, and intention to repatronize the airline. The results suggest that US customers consider service reliability, in-flight comfort, and connections as the key factors determining satisfaction with airline service whereas Korean passengers generally regard reliability, assurance, and risk factors as predictors of satisfaction. The determining factors of customer intention to repatronize the airline are reliability and empathy for US, and reliability and overall risk for Korean customers. The study demonstrates the applicability of SERVPERF as a cross-cultural tool and indicates the importance of perceived risk in cross-cultural studies.

  10. Examination of the fundamental relation between ionic transport and segmental relaxation in polymer electrolytes

    SciTech Connect

    Wang, Yangyang; Fan, Fei; Agapov, Alexander L; Saito, Tomonori; Yang, Jun; Yu, Xiang; Hong, Kunlun; Mays, Jimmy; Sokolov, Alexei P

    2014-01-01

    Replacing traditional liquid electrolytes by polymers will significantly improve electrical energy storage technologies. Despite significant advantages for applications in electrochemical devices, the use of solid polymer electrolytes is strongly limited by their poor ionic conductivity. The classical theory predicts that the ionic transport is dictated by the segmental motion of the polymer matrix. As a result, the low mobility of polymer segments is often regarded as the limiting factor for development of polymers with sufficiently high ionic conductivity. Here, we show that the ionic conductivity in many polymers can be strongly decoupled from their segmental dynamics, in terms of both temperature dependence and relative transport rate. Based on this principle, we developed several polymers with superionic conductivity. The observed fast ion transport suggests a fundamental difference between the ionic transport mechanisms in polymers and small molecules and provides a new paradigm for design of highly conductive polymer electrolytes.

  11. Judgements of relative noisiness of a supersonic transport and several commercial-service aircraft

    NASA Technical Reports Server (NTRS)

    Powell, C. A.

    1977-01-01

    Two laboratory experiments were conducted on the relative noisiness of takeoff and landing operations of a supersonic transport and several other aircraft in current commercial service. A total of 96 subjects made noisiness judgments on 120 tape-recorded flyover noises in the outdoor-acoustic-simulation experiment; 32 different subjects made judgments on the noises in the indoor-acoustic-simulation experiment. The judgments were made by using the method of numerical category scaling. The effective perceived noise level underestimated the noisiness of the supersonic transport by 3.5 db. For takeoff operations, no difference was found between the noisiness of the supersonic transport and the group of other aircraft for the A-weighted rating scale; however, for landing operations, the noisiness of the supersonic transport was overestimated by 3.7 db. Very high correlation was found between the outdoor-simulation experiment and the indoor-simulation experiment.

  12. Reward dependence is related to norepinephrine transporter T-182C gene polymorphism in a Korean population.

    PubMed

    Ham, Byung-Joo; Choi, Myoung-Jin; Lee, Heon-Jeong; Kang, Rhee-Hun; Lee, Min-Soo

    2005-06-01

    It is well established that approximately 50% of the variance in personality traits is genetic. The goal of this study was to investigate a relationship between personality traits and the T-182C polymorphism in the norepinephrine transporter gene. The participants included 115 healthy adults with no history of psychiatric disorders and other physical illness during the past 6 months. All participants were tested with the Temperament and Character Inventory and genotyped norepinephrine transporter gene polymorphism. Differences on the Temperament and Character Inventory dimensions among three groups were examined with one-way analysis of variance. Our study suggests that the norepinephrine transporter T-182C gene polymorphism is associated with reward dependence in Koreans, but the small number of study participants and their sex and age heterogeneity limits generalization of our results. Further studies are necessary with a larger number of homogeneous participants to confirm whether the norepinephrine transporter gene is related to personality traits.

  13. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Brebrick, R. F.; Burger, A.; Dudley, M.; Ramachandran, N.

    2003-01-01

    The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions.

  14. Threshold crossing of device-based intrathoracic impedance trends identifies relatively increased mortality risk

    PubMed Central

    Tang, Wai Hong Wilson; Warman, Eduardo N.; Johnson, James W.; Small, Roy S.; Heywood, James Thomas

    2012-01-01

    Aims Threshold crossings of impedance trends detected by implanted devices have been associated with clinically relevant heart failure events, but long-term prognosis of such events has not been demonstrated. The aim of this study is to examine the relationship between alterations in intrathoracic impedance and mortality risk in patients with implantable devices. Methods and results We reviewed remote monitoring data in the de-identified Medtronic CareLink® Discovery Link that captured intrathoracic impedance trends for >6 months. The initial 6 months of the cardiac and impedance trends were used as the observation period to create the patient groups and cross-referenced with the Social Security Death Index for mortality data. In our study cohort of 21 217 patients, 36% experienced impedance threshold crossing within the initial 6 months of monitoring (defined as the ‘early threshold crossing’ group). Patients with early threshold crossings demonstrated an increased risk of age- and gender-adjusted all-cause mortality [hazard ratio (HR) 2.15, 95% confidence interval (CI) 1.95–2.38, P< 0.0001]. Increased mortality risk remained significant when analysed in subgroups of patients without defibrillator shock (HR 2.10, 95% CI 1.90–2.34, P< 0.0001, n= 1621) or within those patients without device-detectable atrial fibrillation (AF) during the initial 6 months of monitoring (HR 2.09, 95% CI 1.86–2.34, P< 0.0001, n= 17 235). Both the number and the duration of early threshold crossings of impedance trends detectable by implanted devices were associated with increased mortality risk. Furthermore, the improvement of altered impedance trends portends more favourable prognosis. Conclusions Threshold crossing of impedance trends detectable by implanted devices is associated with relatively increased mortality risk even after adjusted for demographic, device-detected AF, or defibrillator shocks. PMID:22677137

  15. On the dynamics of SEIRS epidemic model with transport-related infection.

    PubMed

    Denphedtnong, Adisak; Chinviriyasit, Settapat; Chinviriyasit, Wirawan

    2013-10-01

    Transportation amongst cities is found as one of the main factors which affect the outbreak of diseases. To understand the effect of transport-related infection on disease spread, an SEIRS (Susceptible, Exposed, Infectious, Recovered) epidemic model for two cities is formulated and analyzed. The epidemiological threshold, known as the basic reproduction number, of the model is derived. If the basic reproduction number is below unity, the disease-free equilibrium is locally asymptotically stable. Thus, the disease can be eradicated from the community. There exists an endemic equilibrium which is locally asymptotically stable if the reproduction number is larger than unity. This means that the disease will persist within the community. The results show that transportation among regions will change the disease dynamics and break infection out even if infectious diseases will go to extinction in each isolated region without transport-related infection. In addition, the result shows that transport-related infection intensifies the disease spread if infectious diseases break out to cause an endemic situation in each region, in the sense of that both the absolute and relative size of patients increase. Further, the formulated model is applied to the real data of SARS outbreak in 2003 to study the transmission of disease during the movement between two regions. The results show that the transport-related infection is effected to the number of infected individuals and the duration of outbreak in such the way that the disease becomes more endemic due to the movement between two cities. This study can be helpful in providing the information to public health authorities and policy maker to reduce spreading disease when its occurs.

  16. Effect of pylon cross-sectional geometries on propulsion integration for a low-wing transport

    NASA Technical Reports Server (NTRS)

    Ingraldi, Anthony M.; Naik, Dinesh A.; Pendergraft, Odis C., Jr.

    1993-01-01

    An experimental program was conducted in the Langley 16-Foot Transonic Tunnel to evaluate the performance effects of various types of pylons on a 1/17th-scale, low-wing transport model. The model wing was designed for cruise at a Mach number of 0.77 and a lift coefficient of 0.55. The pylons were tested at two wing semispan locations over a range of toe-in angles. The effects of toe-in angle were found to be minimal, but the variation in geometry had a more pronounced effect on the lift characteristics of the model. A pylon whose maximum thickness occurred at the wing trailing edge, known as a compression pylon, proved to be the best choice in terms of retaining the flow characteristics of the wing without pylons. Practical considerations such as structural viability may necessitate modification of the compression pylon concept in order to take advantage of its apparent benefits.

  17. Fine structure of microwave spike bursts and associated cross-field energy transport

    NASA Technical Reports Server (NTRS)

    Winglee, R. M.; Dulk, G. A.; Pritchett, P. L.

    1988-01-01

    The characteristics of the maser emission from a driven system where energetic electrons continue to flow through the source region is investigated using electronic particle simulations. It is shown that, under appropriate conditions, the maser can efficiently radiate a significant portion of the energy of the fast electrons in a very short time. The radiation is emitted in pulses even though the flow of electrons through the system is at a constant rate. The mission of these pulses is proposed as the source of the fine structure. Under other conditions the dominant maser emission changes from fundamental x-mode to either fundamental z-mode or to electrostatic upper hybrid or Bernstein modes. The bulk of the emission from the maser instability cannot propagate across field lines in this regime, and hence strong local plasma heating is expected, with little energy transport across the magnetic field lines.

  18. Assessment of sedentary behaviors and transport-related activities by questionnaire: a validation study.

    PubMed

    Mensah, Keitly; Maire, Aurélia; Oppert, Jean-Michel; Dugas, Julien; Charreire, Hélène; Weber, Christiane; Simon, Chantal; Nazare, Julie-Anne

    2016-08-09

    Comprehensive assessment of sedentary behavior (SB) and physical activity (PA), including transport-related activities (TRA), is required to design innovative PA promotion strategies. There are few validated instruments that simultaneously assess the different components of human movement according to their context of practice (e.g. work, transport, leisure). We examined test-retest reliability and validity of the Sedentary, Transportation and Activity Questionnaire (STAQ), a newly developed questionnaire dedicated to assessing context-specific SB, TRA and PA. Ninety six subjects (51 women) kept a contextualized activity-logbook and wore a hip accelerometer (Actigraph GT3X + (TM)) for a 7-day or 14-day period, at the end of which they completed the STAQ. Activity-energy expenditure was measured in a subgroup of 45 subjects using the double labeled water (DLW) method. Test-retest reliability was assessed using intra-class-coefficients (ICC) in a subgroup of 32 subjects who filled the questionnaire twice one month apart. Accelerometry was annotated using the logbook to obtain total and context-specific objective estimates of SB. Spearman correlations, Bland-Altman plots and ICC were used to analyze validity with logbook, accelerometry and DLW data validity criteria. Test-retest reliability was fair for total sitting time (ICC = 0.52), good to excellent for work sitting time (ICC = 0.71), transport-related walking (ICC = 0.61) and car use (ICC = 0.67), and leisure screen-related SB (ICC = 0.64-0.79), but poor for total sitting time during leisure and transport-related contexts. For validity, compared to accelerometry, significant correlations were found for STAQ estimates of total (r = 0.54) and context-specific sitting times with stronger correlations for work sitting time (r = 0.88), and screen times (TV/DVD viewing: r = 0.46; other screens: r = 0.42) than for transport (r = 0.35) or leisure-related sitting-times (r

  19. Age-related alterations in the diffusional transport of amino acids across the human Bruch's-choroid complex

    NASA Astrophysics Data System (ADS)

    Hussain, Ali A.; Rowe, Lisa; Marshall, John

    2002-01-01

    Photoreceptor maintenance is dependent on effective delivery of nutrients from the choroidal circulation by way of the acellular Bruch's membrane and the retinal pigment epithelium. Aging of Bruch's membrane is associated with thickening, increased cross linking of fibers, and deposition of debris culminating in reduced porosity. The present study has investigated the effects of aging on the diffusional transport of eight amino acids across Bruch's membrane in 19 human donors. Diffusion studies were carried out in Ussing chambers, and the amount of time-dependent transfer of amino acids across the preparation was quantified by reverse-phase high-performance liquid chromatography. Diffusion rates for all amino acids showed a significant linear decline with aging of donor. The importance of this reduction in delivery of amino acids is discussed with reference to both normal physiology and age-related macular degeneration.

  20. IFT57 stabilizes the assembled intraflagellar transport complex and mediates transport of motility-related flagellar cargo.

    PubMed

    Jiang, Xue; Hernandez, Daniel; Hernandez, Catherine; Ding, Zhaolan; Nan, Beiyan; Aufderheide, Karl; Qin, Hongmin

    2017-03-01

    Intraflagellar transport (IFT) is essential for the assembly and maintenance of flagella and cilia. Recent biochemical studies have shown that IFT complex B (IFT-B) is comprised of two subcomplexes, IFT-B1 and IFT-B2. The IFT-B2 subunit IFT57 lies at the interface between IFT-B1 and IFT-B2. Here, using a Chlamydomonasreinhardtii mutant for IFT57, we tested whether IFT57 is required for IFT-B complex assembly by bridging IFT-B1 and IFT-B2 together. In the ift57-1 mutant, levels of IFT57 and other IFT-B proteins were greatly reduced at the whole-cell level. However, strikingly, in the protease-free flagellar compartment, while the level of IFT57 was reduced, the levels of other IFT particle proteins were not concomitantly reduced but were present at the wild-type level. The IFT movement of the IFT57-deficient IFT particles was also unchanged. Moreover, IFT57 depletion disrupted the flagellar waveform, leading to cell swimming defects. Analysis of the mutant flagellar protein composition showed that certain axonemal proteins were altered. Taken together, these findings suggest that IFT57 does not play an essential structural role in the IFT particle complex but rather functions to prevent it from degradation. Additionally, IFT57 is involved in transporting specific motility-related proteins.

  1. Semi-analytical solution to the frequency-dependent Boltzmann transport equation for cross-plane heat conduction in thin films

    SciTech Connect

    Hua, Chengyun; Minnich, Austin J.

    2015-05-07

    Cross-plane heat transport in thin films with thicknesses comparable to the phonon mean free paths is of both fundamental and practical interest for applications such as light-emitting diodes and quantum well lasers. However, physical insight is difficult to obtain for the cross-plane geometry due to the challenge of solving the Boltzmann equation in a finite domain. Here, we present a semi-analytical series expansion method to solve the transient, frequency-dependent Boltzmann transport equation that is valid from the diffusive to ballistic transport regimes and rigorously includes the frequency-dependence of phonon properties. Further, our method is more than three orders of magnitude faster than prior numerical methods and provides a simple analytical expression for the thermal conductivity as a function of film thickness. Our result enables a straightforward physical understanding of cross-plane heat conduction in thin films.

  2. Physical fitness in relation to transport to school in adolescents: the Danish youth and sports study.

    PubMed

    Andersen, L B; Lawlor, D A; Cooper, A R; Froberg, K; Anderssen, S A

    2009-06-01

    In many Western countries, there are concerns about declining levels of physical activity in school-aged children. Active transport is one way to increase physical activity in children, but few studies have evaluated whether active transport in school-aged children and adolescents has beneficial effects on fitness and, if so, whether different modes of transport affect different aspects of fitness. In this study, we examined the association of active transport with different aspects of fitness in a representative Danish sample of 545 boys and 704 girls, 15-19 years of age. Physical fitness was assessed through a number of field tests, including a maximal cycle test, dynamic and static strength in different muscle groups, muscle endurance, flexibility and agility. Transport to school was reported as the mode of transport. Almost two-thirds of the population cycled to school. Cyclists had higher aerobic power than both walkers and passive travelers (4.6-5.9%). Isometric muscle endurance (10-16%), dynamic muscle endurance in the abdominal muscles (10%) and flexibility (6%) were also higher in cyclists compared with walkers and passive travelers. Mode of travel was not related to leisure-time sports participation. Our findings suggest that commuter bicycling may be a way to improve health in adolescents.

  3. Safety and Health Perceptions in Work-related Transport Activities in Ghanaian Industries.

    PubMed

    Atombo, Charles; Wu, Chaozhong; Tettehfio, Emmanuel O; Nyamuame, Godwin Y; Agbo, Aaron A

    2017-06-01

    With the recent rapid industrialization, occupational safety and health (OSH) has become an important issue in all industrial and human activities. However, incidents of injuries and fatality rates in the Ghanaian industry sector continue to increase. Despite this increase, there is no evidence regarding the element of OSH management in transport activities in Ghanaian industries. Thus, this study aims to examine the perceptions regarding the importance of safety and health in work-related transport activities in Ghanaian industries. A survey data collection technique was used to gather information on best safety practices over a 5-month period. We randomly selected 298 respondents from industries to answer structured questionnaires. The respondents included drivers, transport managers, and safety engineers. Standard multiple regression model and Pearson product-movement correlation were used to performed the analysis. The result shows that for interventions to improve safety and health, concentration has been on drivers' safety practice with less attention to safe driving environments and vehicle usage. Additionally, the respondents are aware of the importance of OSH in transport activities, but the level of integration does not measure up to the standard to reduce operational accidents and injuries. Finally, strong commitment to changing unsafe practices at all levels of operations appears to be the effective way to improve safety situations. OSH culture is not fully complied in industries transport activities. This study, therefore, supports the use of safety seminars and training sessions for industry workers responsible for transport operations for better integration of safety standards.

  4. Kinesin-1/Hsc70-dependent mechanism of slow axonal transport and its relation to fast axonal transport

    PubMed Central

    Terada, Sumio; Kinjo, Masataka; Aihara, Makoto; Takei, Yosuke; Hirokawa, Nobutaka

    2010-01-01

    Cytoplasmic protein transport in axons (‘slow axonal transport') is essential for neuronal homeostasis, and involves Kinesin-1, the same motor for membranous organelle transport (‘fast axonal transport'). However, both molecular mechanisms of slow axonal transport and difference in usage of Kinesin-1 between slow and fast axonal transport have been elusive. Here, we show that slow axonal transport depends on the interaction between the DnaJ-like domain of the kinesin light chain in the Kinesin-1 motor complex and Hsc70, scaffolding between cytoplasmic proteins and Kinesin-1. The domain is within the tetratricopeptide repeat, which can bind to membranous organelles, and competitive perturbation of the domain in squid giant axons disrupted cytoplasmic protein transport and reinforced membranous organelle transport, indicating that this domain might have a function as a switchover system between slow and fast transport by Hsc70. Transgenic mice overexpressing a dominant-negative form of the domain showed delayed slow transport, accelerated fast transport and optic axonopathy. These findings provide a basis for the regulatory mechanism of intracellular transport and its intriguing implication in neuronal dysfunction. PMID:20111006

  5. Quantitative estimates of past changes in ITCZ position and cross-equatorial atmospheric heat transport

    NASA Astrophysics Data System (ADS)

    McGee, D.; Donohoe, A.; Marshall, J.; Ferreira, D.

    2012-12-01

    The mean position and seasonal migration of the Intertropical Convergence Zone (ITCZ) govern the intensity, spatial distribution and seasonality of precipitation throughout the tropics as well as the magnitude and direction of interhemispheric atmospheric heat transport (AHT). As a result of these links to global tropical precipitation and hemispheric heat budgets, paleoclimate studies have commonly sought to use reconstructions of local precipitation and surface winds to identify past shifts in the ITCZ's mean position or seasonal extent. Records indicate close ties between ITCZ position and interhemispheric surface temperature gradients in past climates, with the ITCZ shifting toward the warmer hemisphere. This shift would increase AHT into the cooler hemisphere to at least partially compensate for cooling there. Despite widespread qualitative evidence consistent with ITCZ shifts, few proxy records offer quantitative estimates of the distance of these shifts or of the associated changes in AHT. Here we present a strategy for placing quantitative limits on past changes in mean annual ITCZ position and interhemispheric AHT based on explorations of the modern seasonal cycle and models of present and past climates. We use reconstructions of tropical sea surface temperature gradients to place bounds on globally averaged ITCZ position and interhemispheric AHT during the Last Glacial Maximum, Heinrich Stadial 1, and the Mid-Holocene (6 ka). Though limited by the small number of SST records available, our results suggest that past shifts in the global mean ITCZ were small, typically less than 1 degree of latitude. Past changes in interhemispheric AHT may have been substantial, with anomalies approximately equal to the magnitude of modern interhemispheric AHT. Using constraints on the invariance of the total (ocean+atmosphere) heat transport we suggest possible bounds on fluctuations of the OHT and AMOC during Heinrich Stadial 1. We also explore ITCZ shifts in models and

  6. 49 CFR 622.101 - Cross-reference to procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Cross-reference to procedures. 622.101 Section 622.101 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENVIRONMENTAL IMPACT AND RELATED PROCEDURES Environmental Procedures...

  7. 49 CFR 622.101 - Cross-reference to procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Cross-reference to procedures. 622.101 Section 622.101 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENVIRONMENTAL IMPACT AND RELATED PROCEDURES Environmental Procedures...

  8. Correlation Electron Temperature Fluctuation Measurements on Alcator C-Mod and ASDEX Upgrade: Cross Machine Comparisons and Transport Model Validation

    NASA Astrophysics Data System (ADS)

    White, A. E.; Creely, A. J.; Freethy, S.; Cao, N.; Conway, G. D.; Goerler, T.; Happel, T.; Howard, N. T.; Inman, C.; Rice, J. E.; Rodriguez Fernandez, P.; Sung, C.; C-Mod, Alcator; Upgrade, Asdex

    2016-10-01

    Correlation Electron Cyclotron Emission diagnostics have been developed for Alcator C-Mod and ASDEX Upgrade. Measurements of long wavelength (ktheta rhos <0.5) electron temperature fluctuations have been measured in the core plasma (0.5 cross-machine comparisons, as well as multi-machine transport model validation, using nonlinear simulations with the GENE and GYRO codes and reduced models such as TGLF. Electron temperature fluctuations, and the correlation with density fluctuations, which can be measured with coupled radiometer / reflectometer diagnostics, provide valuable constraints on gyrokinetic models. Recent results in transport model validation at both C-Mod and AUG are presented. This work is supported by the US DOE under Grants DE-SC0006419 and DEFC02-99ER54512-CMOD.

  9. Cross-borehole ground-penetrating radar for monitoring and imaging solute transport within the vadose zone

    NASA Astrophysics Data System (ADS)

    Chang, Ping-Yu; Alumbaugh, David; Brainard, Jim; Hall, Laila

    2006-10-01

    A two-stage salt infiltration experiment was conducted to simulate vadose zone contaminant transport and to investigate mechanisms that affect the development of contaminant plumes in the unsaturated zone. A low-concentration sodium chloride solution (1024 ppm) was first infiltrated for 7 months through one third of a specially designed infiltrometer at a rate of 2.7 cm/d, with tap water infiltrating through the remaining two thirds at the same rate. This first stage was followed by 3 months of running tap water through the entire infiltrometer to flush the system while maintaining the same unsaturated infiltration conditions. Next, the concentration of the sodium chloride solution was increased to 6900 ppm, which was introduced at the same infiltration rate over a different one third of the infiltrometer for 3 months. This paper focuses on using cross-borehole ground-penetrating radar attenuation tomography to image the developing plume in a time-lapse sense. Attenuation is shown to increase with increasing salt concentration, and the time-lapse images indicate that regions of anomalous attenuation develop in locations where pockets of higher moisture content exist. This suggests that either preferential transport pathways develop within the finer-grained sediments exhibiting greater water retention capability or salt ions are being incorporated into the mineral surficial charge within the fine-grained materials.

  10. New evidence and modeling studies of cross-tropopause transport of water substance by deep convective storms

    NASA Astrophysics Data System (ADS)

    Wang, P. K.

    2016-12-01

    Water vapor in the stratosphere can intercept substantial amount of terrestrial infrared radiation, thus causing exasperation of global warming at the surface due to increasing CO2. It also serves as the source material for making stratospheric odd hydrogen species that may cause ozone depletion through certain catalytic cycles. It is therefore very important to identify the process via which water vapor is transported across the tropopause into the stratosphere. Transport of water substance into the stratosphere by deep convective storms have been investigated by the author since around 2000, and in 2003 he proposed that it is the internal gravity wave breaking at the storm top that causes the water substance to penetrate through the tropopause and enter the stratosphere. Since then increasing evidence, including the observation of above-anvil cirrus plumes, jumping cirrus at the storm top, and the so-called pancake clouds, have been suggested as the manifestation of this wave breaking phenomenon. Cloud-resolving model studies did show the clear connection between these phenomena and wave breaking. Still there are several unresolved questions such as whether or not the jumping cirrus eventually evolves into plumes and whether the pancake clouds really exist. In this paper, I will show new aircraft and satellite observational evidence that confirm the above questions. These evidence demonstrate that the jumping cirrus can indeed evolve into plumes as observed by satellite storm images and that new rapid scan satellite storm images reveal the existence of the pancake clouds. New high resolution model simulations show cloud top features that match the observation very well and thus vindicating the role of gravity wave breaking in this process. Model results also give an estimate of the cross-tropopause transport of water substance that is much larger than previously thought.

  11. Assessing resilience of western rangelands to transportation-related land-use change

    USDA-ARS?s Scientific Manuscript database

    The amount and extent of transportation related activity in western rangelands has rapidly increased in recent decades. This increase is due to a variety of factors including oil and gas development, recreational activities, and ex-urban development. In addition to areas directly impacted by infrast...

  12. Transport-Related Social Exclusion amongst Older People in Rural Southwest England and Wales

    ERIC Educational Resources Information Center

    Shergold, Ian; Parkhurst, Graham

    2012-01-01

    Rural dwelling and older age are both associated with a higher risk of social exclusion, with accessibility identified as having an important facilitating role. The interactions between transport-related exclusion and older age, particularly in a rural context, are considered though analysis of quantitative and qualitative data collected from over…

  13. 34 CFR 200.48 - Funding for choice-related transportation and supplemental educational services.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Funding for choice-related transportation and supplemental educational services. 200.48 Section 200.48 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION TITLE I-IMPROVING...

  14. 34 CFR 200.48 - Funding for choice-related transportation and supplemental educational services.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Funding for choice-related transportation and supplemental educational services. 200.48 Section 200.48 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION TITLE...

  15. 34 CFR 200.48 - Funding for choice-related transportation and supplemental educational services.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Funding for choice-related transportation and supplemental educational services. 200.48 Section 200.48 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION TITLE...

  16. 25 CFR 170.428 - How is the State Transportation Improvement Program related to the IRRTIP?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How is the State Transportation Improvement Program related to the IRRTIP? 170.428 Section 170.428 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM Planning, Design, and Construction of Indian...

  17. Transport-Related Social Exclusion amongst Older People in Rural Southwest England and Wales

    ERIC Educational Resources Information Center

    Shergold, Ian; Parkhurst, Graham

    2012-01-01

    Rural dwelling and older age are both associated with a higher risk of social exclusion, with accessibility identified as having an important facilitating role. The interactions between transport-related exclusion and older age, particularly in a rural context, are considered though analysis of quantitative and qualitative data collected from over…

  18. 40 CFR 93.122 - Procedures for determining regional transportation-related emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... growth in population and historical growth trends for VMT per person. These methods must also consider... population over 200,000. (1) By January 1, 1997, estimates of regional transportation-related emissions used... trends and other factors, and the results must be documented; (ii) Land use, population, employment, and...

  19. 40 CFR 93.122 - Procedures for determining regional transportation-related emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... growth in population and historical growth trends for VMT per person. These methods must also consider... population over 200,000. (1) By January 1, 1997, estimates of regional transportation-related emissions used... trends and other factors, and the results must be documented; (ii) Land use, population, employment, and...

  20. 40 CFR 93.122 - Procedures for determining regional transportation-related emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... growth in population and historical growth trends for VMT per person. These methods must also consider... population over 200,000. (1) By January 1, 1997, estimates of regional transportation-related emissions used... trends and other factors, and the results must be documented; (ii) Land use, population, employment, and...

  1. 40 CFR 93.122 - Procedures for determining regional transportation-related emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... growth in population and historical growth trends for VMT per person. These methods must also consider... population over 200,000. (1) By January 1, 1997, estimates of regional transportation-related emissions used... trends and other factors, and the results must be documented; (ii) Land use, population, employment, and...

  2. Turbulent heating and cross-field transport near the magnetopause from THEMIS

    NASA Astrophysics Data System (ADS)

    Chaston, C.; Bonnell, J.; McFadden, J. P.; Carlson, C. W.; Cully, C.; Le Contel, O.; Roux, A.; Auster, H. U.; Glassmeier, K. H.; Angelopoulos, V.; Russell, C. T.

    2008-05-01

    We demonstrate that the low frequency broadband magnetic fluctuations observed during THEMIS spacecraft traversals near the Earth's magnetopause may be described as a turbulent spectrum of Doppler shifted kinetic Alfvén waves (KAWs). These waves are most intense along reconnected flux-tubes in the magnetosheath just outside the magnetopause. We identify distinct power-law scalings of wave spectral energy density in wavenumber and show that Landau (LD) and transit time damping (TD) on ions and electrons is largest at the wavenumber where the power-law index changes. The threshold amplitude for stochastic ion scattering/acceleration is also exceeded by these waves. These acceleration processes are manifest in observations of field-aligned and transverse heating of electrons and ions respectively. From integration over the range of observed wavenumbers we show that, if the wave-normal angles are sufficiently large, these waves can provide diffusive transport of magnetosheath plasmas across the magnetopause at up to the Bohm rate.

  3. Transient electrokinetic transport in micro/nanofluidic systems with sudden expansion and contraction cross sections

    NASA Astrophysics Data System (ADS)

    Chein, Reiyu; Liao, Yuchung

    2013-03-01

    This study numerically investigates electrokinetic transport in a micro/nanofluidic system by solving the transient Poisson, Nernst-Planck, and Navier-Stokes equations simultaneously. The considered system is a nanochannel connected to two micro channels at its ends. Under various applied electric potential biases, the concentration polarization effect on the fluid flow, induced pressure, and electric current is examined. By comparing with the Donnan equilibrium condition and electroosmotic flow in the microscale dimension, electric body force due to non-zero charge density is the mechanism for producing vortex flow and inducing a positive pressure gradient on the anodic side of the system. The diffusive boundary layer thickness is reduced due to stirring by the generated vortex flow, resulting in over-limiting current when the applied electric potential bias is high. The steady-state current voltage curve indicates that in the Ohmic regime, higher current can be obtained when the surface charge density is large due to higher fluid velocity. In the limiting and over-limiting current regimes, higher electric current can be obtained when the nanochannel is larger with smaller surface density because more ions are available for carrying the current. The nanochannel size effect on the limiting and over-limiting current magnitudes is insignificant when the surface charge density is large.

  4. Relations among transepithelial sodium transport, potassium exchange, and cell volume in rabbit ileum.

    PubMed

    Nellans, H N; Schultz, S G

    1976-10-01

    The relation between active transepithelial Na transport across rabbit ileum and 42K exchange from the serosal solution across the basolateral membranes has been explored. Although 42K influx across the basolateral membranes is inhibited by ouabain and by complete depletion of cell Na, it is not affected when transepithelial Na transport is abolished (i.e. in the presence of an Na-free mucosal solution) or stimulated (i.e. when glucose or alanine is added to the mucosal solution). We are unable to detect any relation between the ouabain-sensitive Na-K exchange mechanism responsible for the maintenance of intracellular Na and K concentrations and active transcellular Na transport. In addition, the maintenance of cell volume (water content) does not appear to be dependent upon transepithelial Na transport or the ouabain-sensitive Na-K exchange pump. Although the results of these studies cannot be considered conclusive, they raise serious questions regarding the role of the Na-K exchange pump, located at the basolateral membranes, in active transepithelial Na transport and the maintenance of cell volume.

  5. Diagnosing cross-shelf transport along an ocean front: An observational case study in the Gulf of Lion

    NASA Astrophysics Data System (ADS)

    Nencioli, F.; Petrenko, A. A.; Doglioli, A. M.

    2016-10-01

    Exchanges between coastal regions and the open ocean are often associated with intermittent and localized processes such as eddies, fronts, and filaments. Since these features are difficult to observe, their impact has been predominantly investigated using numerical models and remote sensing. In this study, satellite sea surface temperature maps, Lagrangian surface drifter trajectories, and ship-based surveys of currents and hydrography from the Latex10 campaign are used to quantify cross-shelf exchanges associated with a temperature front in the western Gulf of Lion. Satellite imagery and thermosalinograph sections provide the characterization of the various water masses associated with the front. Lagrangian drifter trajectories are used to identify the main transport structures and to quantify the velocity components associated with near-inertial oscillations. These are removed from the instantaneous ADCP observations with which the cross-shelf exchanges are then computed. The results indicate an average outflow of 0.074 ± 0.013 Sv and an inflow of 0.021 ± 0.006 Sv. Integrated over the 2 week lifetime of the front, such outflow induced a total export of ˜90 ± 14 km3 of water, indicating that three to four of such events are sufficient to completely renew the surface waters of the Gulf of Lion. The total import was ˜25 ± 7 km3, suggesting larger inflows at depth or in the eastern part of the gulf to maintain its volume balance. These in situ estimates represent a key term of comparison for the further development of numerical model-based and satellite-based studies of cross-shelf exchanges associated with this type of processes.

  6. Nano-cross-junction effect on phonon transport in silicon nanowire cages

    NASA Astrophysics Data System (ADS)

    Ma, Dengke; Ding, Hongru; Meng, Han; Feng, Lei; Wu, Yue; Shiomi, Junichiro; Yang, Nuo

    2016-10-01

    Wave effects of phonons can give rise to controllability of heat conduction in nanostructures beyond that by particle scattering at surfaces and interfaces. In this paper, we propose a new class of three-dimensional nanostructures: a silicon-nanowire-cage (SiNWC) structure consisting of silicon nanowires (SiNWs) connected by nano-cross-junctions. We perform equilibrium molecular dynamics simulations and find an ultralow value of thermal conductivity of SiNWC, 0.173 W m-1K-1 , which is one order lower than that of SiNWs. By further modal analysis and atomistic Green's function calculations, we identify that the large reduction is due to significant phonon localization induced by the phonon local resonance and hybridization at the junction part in a wide range of phonon modes. This localization effect does not require the cage to be periodic, unlike the phononic crystals, and can be realized in structures that are easier to synthesize, for instance in a form of randomly oriented SiNW network.

  7. Relating reactive solute transport to hierarchical and multiscale sedimentary architecture in a Lagrangian-based transport model: 2. Particle displacement variance

    NASA Astrophysics Data System (ADS)

    Soltanian, Mohamad Reza; Ritzi, Robert W.; Huang, Chao Cheng; Dai, Zhenxue

    2015-03-01

    This series of papers addresses the transport of sorbing solutes in groundwater. In part 2, plume dispersion, as quantified by the particle displacement variance, X11R>(t>), is linked to hierarchical sedimentary architecture using a Lagrangian-based transport model. This allows for a fundamental understanding of how dispersion arises from the hierarchical architecture of sedimentary facies, and allows for a quantitative decomposition of dispersion into facies-related contributions at different scales within the hierarchy. As in part 1, the plume behavior is assumed to be controlled by linear-equilibrium sorption and the heterogeneity in both the log permeability, Y=ln⁡>(k>), and the log distribution coefficient, Ξ=ln⁡>(Kd>). Heterogeneity in Y and Ξ arises from sedimentary processes and is structured by the consequent sedimentary architecture. Our goal is to understand the basic science of the dispersion process at this very fundamental level. The spatial auto and cross covariances for the relevant attributes are linear sums of terms corresponding to the probability of transitioning across stratal facies types defined at different scales. Unlike previous studies that used empirical relationships for the spatial covariances, here the model parameters are developed from independent measurements of physically quantifiable attributes of the stratal architecture (i.e., proportions and lengths of facies types, and univariate statistics for Y and Ξ). Nothing is assumed about Y-Ξ point correlation; it is allowed to differ by facies type. However, it is assumed that Y and Ξ variance is small but meaningful, and that pore-scale dispersion is negligible. The time-dependent spreading rate is a function of the effective ranges of the cross-transition probability structures (i.e., the ranges of indicator correlation structures) for each relevant scale of stratal hierarchy. As in part 1, the well-documented perchloroethene (PCE) tracer test at the Borden research site is

  8. Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion

    USGS Publications Warehouse

    Disney, M.R.; Hellgren, E.C.; Davis, C.A.; Leslie, David M.; Engle, David M.

    2008-01-01

    Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention than relationships to other metrics of fragmentation, particularly edge characteristics. We tested the hypothesis that relative abundance of mesopredators (e.g., raccoons and Virginia opossums) was related negatively to size of forest patch. We delineated 15 patches of oak (Quercus) forest ranging from 0.2 to 55.3 ha within a grassland-woodland mosaic in the cross-timbers ecoregion of Oklahoma. Scent stations and live traps within these patches were used to index relative abundance of mesopredators in summers 2003 and 2004. Both indices of relative abundance were related weakly and negatively to area of forest patch. However, rate of capture and visitation to scent station were not correlated consistently throughout the study. Our results suggested that the two methods to index abundance provided separate information on functional and numerical responses to size of patch. Our evidence that mesopredators within the cross timbers were more likely to be in smaller patches of oak forest may have implications to success of avian nesting in these patches.

  9. Performance of bed-load transport equations relative to geomorphic significance: Predicting effective discharge and its transport rate

    Treesearch

    Jeffrey J. Barry; John M. Buffington; Peter Goodwin; John .G. King; William W. Emmett

    2008-01-01

    Previous studies assessing the accuracy of bed-load transport equations have considered equation performance statistically based on paired observations of measured and predicted bed-load transport rates. However, transport measurements were typically taken during low flows, biasing the assessment of equation performance toward low discharges, and because equation...

  10. Neuron-glia cross talk revealed in reverberating networks by simultaneous extracellular recording of spikes and astrocytes' glutamate transporter and K+ currents.

    PubMed

    Wanke, Enzo; Gullo, Francesca; Dossi, Elena; Valenza, Gaetano; Becchetti, Andrea

    2016-12-01

    Astrocytes uptake synaptically released glutamate with electrogenic transporters (GluT) and buffer the spike-dependent extracellular K(+) excess with background K(+) channels. We studied neuronal spikes and the slower astrocytic signals on reverberating neocortical cultures and organotypic slices from mouse brains. Spike trains and glial responses were simultaneously captured from individual sites of multielectrode arrays (MEA) by splitting the recorded traces into appropriate filters and reconstructing the original signal by deconvolution. GluT currents were identified by using dl-threo-β-benzyloxyaspartate (TBOA). K(+) currents were blocked by 30 μM Ba(2+), suggesting a major contribution of inwardly rectifying K(+) currents. Both types of current were tightly correlated with the spike rate, and their astrocytic origin was tested in primary cultures by blocking glial proliferation with cytosine β-d-arabinofuranoside (AraC). The spike-related, time-locked inward and outward K(+) currents in different regions of the astrocyte syncytium were consistent with the assumptions of the spatial K(+) buffering model. In organotypic slices from ventral tegmental area and prefrontal cortex, the GluT current amplitudes exceeded those observed in primary cultures by several orders of magnitude, which allowed to directly measure transporter currents with a single electrode. Simultaneously measuring cell signals displaying widely different amplitudes and kinetics will help clarify the neuron-glia interplay and make it possible to follow the cross talk between different cell types in excitable as well as nonexcitable tissue.

  11. Neuron-glia cross talk revealed in reverberating networks by simultaneous extracellular recording of spikes and astrocytes' glutamate transporter and K+ currents

    PubMed Central

    Wanke, Enzo; Gullo, Francesca; Dossi, Elena; Valenza, Gaetano

    2016-01-01

    Astrocytes uptake synaptically released glutamate with electrogenic transporters (GluT) and buffer the spike-dependent extracellular K+ excess with background K+ channels. We studied neuronal spikes and the slower astrocytic signals on reverberating neocortical cultures and organotypic slices from mouse brains. Spike trains and glial responses were simultaneously captured from individual sites of multielectrode arrays (MEA) by splitting the recorded traces into appropriate filters and reconstructing the original signal by deconvolution. GluT currents were identified by using dl-threo-β-benzyloxyaspartate (TBOA). K+ currents were blocked by 30 μM Ba2+, suggesting a major contribution of inwardly rectifying K+ currents. Both types of current were tightly correlated with the spike rate, and their astrocytic origin was tested in primary cultures by blocking glial proliferation with cytosine β-d-arabinofuranoside (AraC). The spike-related, time-locked inward and outward K+ currents in different regions of the astrocyte syncytium were consistent with the assumptions of the spatial K+ buffering model. In organotypic slices from ventral tegmental area and prefrontal cortex, the GluT current amplitudes exceeded those observed in primary cultures by several orders of magnitude, which allowed to directly measure transporter currents with a single electrode. Simultaneously measuring cell signals displaying widely different amplitudes and kinetics will help clarify the neuron-glia interplay and make it possible to follow the cross talk between different cell types in excitable as well as nonexcitable tissue. PMID:27683885

  12. Verbal Working Memory Is Related to the Acquisition of Cross-Linguistic Phonological Regularities

    PubMed Central

    Bosma, Evelyn; Heeringa, Wilbert; Hoekstra, Eric; Versloot, Arjen; Blom, Elma

    2017-01-01

    Closely related languages share cross-linguistic phonological regularities, such as Frisian -âld [ͻ:t] and Dutch -oud [ʱut], as in the cognate pairs kâld [kͻ:t] – koud [kʱut] ‘cold’ and wâld [wͻ:t] – woud [wʱut] ‘forest’. Within Bybee’s (1995, 2001, 2008, 2010) network model, these regularities are, just like grammatical rules within a language, generalizations that emerge from schemas of phonologically and semantically related words. Previous research has shown that verbal working memory is related to the acquisition of grammar, but not vocabulary. This suggests that verbal working memory supports the acquisition of linguistic regularities. In order to test this hypothesis we investigated whether verbal working memory is also related to the acquisition of cross-linguistic phonological regularities. For three consecutive years, 5- to 8-year-old Frisian-Dutch bilingual children (n = 120) were tested annually on verbal working memory and a Frisian receptive vocabulary task that comprised four cognate categories: (1) identical cognates, (2) non-identical cognates that either do or (3) do not exhibit a phonological regularity between Frisian and Dutch, and (4) non-cognates. The results showed that verbal working memory had a significantly stronger effect on cognate category (2) than on the other three cognate categories. This suggests that verbal working memory is related to the acquisition of cross-linguistic phonological regularities. More generally, it confirms the hypothesis that verbal working memory plays a role in the acquisition of linguistic regularities. PMID:28955260

  13. Verbal Working Memory Is Related to the Acquisition of Cross-Linguistic Phonological Regularities.

    PubMed

    Bosma, Evelyn; Heeringa, Wilbert; Hoekstra, Eric; Versloot, Arjen; Blom, Elma

    2017-01-01

    Closely related languages share cross-linguistic phonological regularities, such as Frisian -âld [ͻ:t] and Dutch -oud [ʱut], as in the cognate pairs kâld [kͻ:t] - koud [kʱut] 'cold' and wâld [wͻ:t] - woud [wʱut] 'forest'. Within Bybee's (1995, 2001, 2008, 2010) network model, these regularities are, just like grammatical rules within a language, generalizations that emerge from schemas of phonologically and semantically related words. Previous research has shown that verbal working memory is related to the acquisition of grammar, but not vocabulary. This suggests that verbal working memory supports the acquisition of linguistic regularities. In order to test this hypothesis we investigated whether verbal working memory is also related to the acquisition of cross-linguistic phonological regularities. For three consecutive years, 5- to 8-year-old Frisian-Dutch bilingual children (n = 120) were tested annually on verbal working memory and a Frisian receptive vocabulary task that comprised four cognate categories: (1) identical cognates, (2) non-identical cognates that either do or (3) do not exhibit a phonological regularity between Frisian and Dutch, and (4) non-cognates. The results showed that verbal working memory had a significantly stronger effect on cognate category (2) than on the other three cognate categories. This suggests that verbal working memory is related to the acquisition of cross-linguistic phonological regularities. More generally, it confirms the hypothesis that verbal working memory plays a role in the acquisition of linguistic regularities.

  14. Maillard reaction and protein cross-linking in relation to the solubility of milk powders.

    PubMed

    Le, Thao T; Bhandari, Bhesh; Holland, John W; Deeth, Hilton C

    2011-12-14

    Protein changes in relation to solubility, Maillard reaction (MR), and protein cross-linking in whole milk powder (WMP), skim milk powder (SMP), and whey protein concentrate (WPC) stored at different relative humidities (RHs) were investigated by chemical and electrophoretic methods. WMP and SMP reached minimum solubility rapidly, while WPC showed no change in solubility. The loss of solubility corresponded with development of high-molecular-weight protein complexes observed by two-dimensional electrophoresis. The maximal MR rate occurred at 66% RH for WMP and SMP (high lactose/protein ratios) and 84% RH for WPC (low lactose/protein ratios) based on the furosine and hydroxymethylfurfural contents. However, browning was greatest at 84% RH in all powders. The minimum solubility corresponded with the casein and fat contents. The retention of solubility and minimal protein cross-linking of WPC compared to casein-containing powders suggest that the casein content and cross-linking strongly influence the decrease in the solubility of milk powder.

  15. Evidences for a role of protein cross-links in transglutaminase-related disease.

    PubMed

    Tabolacci, Claudio; Lentini, Alessandro; Provenzano, Bruno; Beninati, Simone

    2012-02-01

    Transglutaminases (TGs) are a large family of related and ubiquitous enzymes that catalyze the cross-linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate. Considerable and intense progress has been made in the understanding of the chemistry, molecular biology and cell biology of TGs. The knowledge that very different physiological and pathological processes are dependent on the presence of adequate levels of these cross-linking enzymes and on the amount of both free and protein-conjugated polyamines by TG, has generated an incredible amount of original research and review articles. It is clear that TG-mediated reactions are essential for some biological processes, such as blood coagulation, skin barrier formation and extracellular matrix assembly, but may also be involved in pathogenetic mechanisms responsible for several human diseases, such as cancer, AIDS, neurodegenerative disorders, celiac disease, and eye lens opacification. We present here a comprehensive review of recent insights into the pathophysiology of TGs related to their protein cross-linking activity.

  16. [The current problems and cross-cultural perspectives of patient-doctor relation: an overview].

    PubMed

    Koch, Eckhardt; Turgut, Tolga

    2004-01-01

    The success of the treatment in medicine, especially in psychiatry is based on the form and the strength of the patient-doctor relation. This complex and dynamic relation is changing in accordance with the social and technological development of the society. The context of the patient-doctor relation is determined by the present day culture as well as the traditional background. An overview of current patient-doctor relation and of problems that physicians and in particular psychiatrists meet is presented. Physicians have responsibilities in building patient-doctor relation. The ethical and legal aspects of these responsibilities are presented. The former paternalistic type of patient-doctor relation is evolving into a more equal and democratic relation. New problems are being encountered continuously in the changing process. Beside the of the process itself, the effects of progress in medical technology and communication systems on patient-doctor relation and the pressure, put from the insurance companies and/or authorities on physicians, which impair the trust between the physician and his patient, are making the process more difficult. The issues of compliance, sexual harassment and unique problems of patient-doctor relations in psychiatry are the other subtopics in the article. The cross-cultural aspects of patient-doctor relations and encountered clinical problems are discussed with case examples particularly about Turkish immigrants, who live in Germany. Suggestions for psychiatrists in Germany to work out the challenges facing them are presented in the conclusion.

  17. Possible relations between general population suicide rates and societal crime: a cross-national study.

    PubMed

    Shah, Ajit; Bhandarkar, Ritesh

    2008-10-01

    Crime may be associated with a less structured society, less social integration, and feelings of less security and greater distress among citizens, which characteristics may lead to mental illness and subsequent suicide. Therefore, a cross-national analysis examining the association of general population suicide rates with percent of males and females in the population victimised by different categories of crime was undertaken using cross-national data from the World Health Organization and United Nations for 42 countries. Spearman correlations were generally weak and not statistically significant. Those values were at variance with the study's hypothesis and may be explained by several factors, including methodological issues. Individual-level case-control or cohort studies of suicides and attempted suicides in the general population may permit exploration of the relation of general population suicides with experience and percent by nations of being victimised by crime.

  18. Characterization of microsatellite loci in Yucca brevifolia (Agavaceae) and cross-amplification in related species.

    PubMed

    Flatz, Ramona; Yoder, Jeremy B; Lee-Barnes, Edyth; Smith, Christopher I

    2011-03-01

    Microsatellite primers were characterized in Yucca brevifolia for use in population genetic studies and, particularly, analyses of gene flow between varieties. We characterized 12 microsatellite loci polymorphic in Yucca brevifolia by screening primers that were developed using an SSR-enriched library or which were previously described in Yucca filamentosa. Genetic analysis of four populations resulted in the mean number of alleles per locus ranging from 10.25 to 14.58 and mean expected heterozygosity from 0.78 to 0.88. Cross-amplification of all 12 loci was attempted in six additional yucca species. These loci should prove useful for population genetic research in Yucca brevifolia, and cross-amplification of these loci in related species suggests that they may be useful in studies of hybridization and introgression between species.

  19. 49 CFR 236.53 - Track circuit feed at grade crossing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Track circuit feed at grade crossing. 236.53 Section 236.53 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Instructions: All Systems Track Circuits § 236.53 Track circuit feed at grade crossing. At grade crossing with...

  20. 49 CFR 236.53 - Track circuit feed at grade crossing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Track circuit feed at grade crossing. 236.53 Section 236.53 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Instructions: All Systems Track Circuits § 236.53 Track circuit feed at grade crossing. At grade crossing with...

  1. 49 CFR 222.49 - Who may file Grade Crossing Inventory Forms?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Who may file Grade Crossing Inventory Forms? 222.49 Section 222.49 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL... § 222.49 Who may file Grade Crossing Inventory Forms? (a) Grade Crossing Inventory Forms required to...

  2. Transportability

    DTIC Science & Technology

    2013-04-25

    psi). (g) Maximum axle load (pneumatic tires) - 2,268 kg (5,000 lb). (h) Maximum wheel load (pneumatic tires) - 1,134 kg (2,500 lb). (i...survivability following the shock or vibration environment induced. Vehicles not typically transported with payload such as wreckers, truck tractors ...combination weight rating (GCWR) means the value specified by the manufacturer as the loaded weight of the combination vehicle. (d) Gross axle weight

  3. Transportation

    DTIC Science & Technology

    2007-01-01

    International (cont.) European Commission – Directorate General for Energy and Transport, Brussels, Belgium Headquarters Netherlands Customs ...100,000 by 2014. As a result of these challenges and due to the increase in intermodal freight traffic, a customer /client relationship has...increase by 50% domestically and 110% internationally by 2016 (CRS, 2007). United Parcel Service (UPS), FedEx, and DHL currently control the package

  4. Stomatal control of gas-exchange is related to assimilate transport from leaves

    NASA Astrophysics Data System (ADS)

    Nikinmaa, E.; Holtta, T.; Sevanto, S.; Makela, A.; Hari, P.; Vesala, T.

    2009-04-01

    In land plants, the carbon fluxes are closely associated with those of water. The loss of water from leaves pulls water from soil in plants. High transpiration relative to compensating water flux from soil increases the tension of water column that may lead to its rupture and catastrophic dysfunction of the xylem if the transpiration rate is not regulated. Modification of the size of stomatal openings in leaves regulates the interconnected fluxes of water and carbon. Stomatal regulation of transpiration has direct influence also on the carbon transport from source leaves to sinks. Under given conditions, the water tension of xylem in leaves is linearly related to stomatal conductance while the assimilation rate, which is linked to the loading capacity, has saturating relationship with stomatal conductance. High sugar loading at source could compensate for the high water tension in xylem resulting from eg. high transpiration. However, excessive loading rate of the most commonly transported sugar, sucrose, causes rapid viscosity build up that effectively blocks the phloem transport. Assimilate transport from the shoot is a clear requirement for continuous photosynthetic production in leaves. Without transport the storage capacity of the leaves would be rapidly exhausted and accumulation of excess sugars in leaves lead to downregulation of photosynthesis. In this presentation we study the stomatal response to environment and its linkage to xylem and phloem tranport with dynamic model. We hypothesize that stomatal reaction to environment would maintain maximal assimilate transport in phloem under those conditions. We added to the xylem phloem transport model stomatal control of leaf gas-exchange, light and CO2 concentration dependent photosynthesis rate and carbon storage in leaf. For each time step we varied the stomatal conductance and selected the sollution that maximised the transport of assimilates in phloem. Our hypothesis reproduced realistically stomatal

  5. Noise annoyance is related to the presence of urban public transport.

    PubMed

    Paunović, Katarina; Belojević, Goran; Jakovljević, Branko

    2014-05-15

    The association between noise annoyance and public transport as a source of noise has not been studied previously. The aim was to study noise annoyance in an urban population due to the presence, the type and the number of public transport vehicles, in relation to other acoustical and non-acoustical parameters. The study sample comprised 5861 adults residing in 118 streets in the city center of Belgrade. The presence, the type and the number of public transport vehicles were assessed using official transport maps and matched with residential addresses. Noise annoyance was assessed by a questionnaire including a self-report five-graded scale. 'High noise annoyance' was defined by merging 'very' and 'extremely' annoyed answers. Significant predictors of high noise annoyance were the presence of public transport at daytime (yes vs. no) (odds ratio=1.47, 95% confidence interval=1.28-1.70), and at night (yes vs. no) (OR=1.39, 95% CI=1.20-1.61). Residing in the streets with more than 79 public transport vehicles per hour (3rd tercile vs. 1st tercile) predicted high noise annoyance at daytime (OR=1.64, 95% CI=1.18-2.27). Residing in the streets with buses and trams at night ('bus and tram' vs. no public transport) increased the risk of high noise annoyance (OR=2.67, 95% CI=1.78-4.09). These associations were independent from noise sensitivity, orientation of bedroom windows, floor level, and equivalent noise levels. Living in the apartment with bedroom windows facing the street was the strongest confounder for the association between noise annoyance, noise levels and public transport. The study has identified the presence of public transport at daytime and at night as a significant and independent predictor of high noise annoyance. Future intervention measures should concern the presence, the type and the number of public transport vehicles in order to reduce noise annoyance reactions in urban areas. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Brebrick, Robert F.; Volz, Martin P.; Burger, Arnold; Dudley, Michael; Matyi, Richard J.; Ramachandran, Narayanan; Sha, Yi-Gao; Volz, Martin P.; Shih, Hung-Dah

    2001-01-01

    Crystal growth by vapor transport has several distinct advantages over melt growth techniques. Among various potential benefits from material processing in reduced gravity the followings two are considered to be related to crystal growth by vapor transport: (1) elimination of the crystal weight and its influence on the defect formation and (2) reduction of natural buoyancy-driven convective flows arising from thermally and/ or solutally induced density gradient in fluids. The previous results on vapor crystal growth of semiconductors showed the improvements in surface morphology, crystalline quality, electrical properties and dopant distribution of the crystals grown in reduced gravity as compared to the crystals grown on Earth. But the mechanisms, which are responsible for the improvements and cause the gravitational effects on the complicated and coupled processes of vapor mass transport and growth kinetics, are not well understood.

  7. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Brebrick, Robert F.; Volz, Martin P.; Burger, Arnold; Dudley, Michael; Matyi, Richard J.; Ramachandran, Narayanan; Sha, Yi-Gao; Volz, Martin P.; Shih, Hung-Dah

    2001-01-01

    Crystal growth by vapor transport has several distinct advantages over melt growth techniques. Among various potential benefits from material processing in reduced gravity the followings two are considered to be related to crystal growth by vapor transport: (1) elimination of the crystal weight and its influence on the defect formation and (2) reduction of natural buoyancy-driven convective flows arising from thermally and/ or solutally induced density gradient in fluids. The previous results on vapor crystal growth of semiconductors showed the improvements in surface morphology, crystalline quality, electrical properties and dopant distribution of the crystals grown in reduced gravity as compared to the crystals grown on Earth. But the mechanisms, which are responsible for the improvements and cause the gravitational effects on the complicated and coupled processes of vapor mass transport and growth kinetics, are not well understood.

  8. Origin of the relatively low transport mobility of graphene grown through chemical vapor deposition

    PubMed Central

    Song, H. S.; Li, S. L.; Miyazaki, H.; Sato, S.; Hayashi, K.; Yamada, A.; Yokoyama, N.; Tsukagoshi, K.

    2012-01-01

    The reasons for the relatively low transport mobility of graphene grown through chemical vapor deposition (CVD-G), which include point defect, surface contamination, and line defect, were analyzed in the current study. A series of control experiments demonstrated that the determinant factor for the low transport mobility of CVD-G did not arise from point defects or surface contaminations, but stemmed from line defects induced by grain boundaries. Electron microscopies characterized the presence of grain boundaries and indicated the polycrystalline nature of the CVD-G. Field-effect transistors based on CVD-G without the grain boundary obtained a transport mobility comparative to that of Kish graphene, which directly indicated the detrimental effect of grain boundaries. The effect of grain boundary on transport mobility was qualitatively explained using a potential barrier model. Furthermore, the conduction mechanism of CVD-G was also investigated using the temperature dependence measurements. This study can help understand the intrinsic transport features of CVD-G. PMID:22468224

  9. Neurobehavioral effects of transportation noise in primary schoolchildren: a cross-sectional study

    PubMed Central

    2010-01-01

    Background Due to shortcomings in the design, no source-specific exposure-effect relations are as yet available describing the effects of noise on children's cognitive performance. This paper reports on a study investigating the effects of aircraft and road traffic noise exposure on the cognitive performance of primary schoolchildren in both the home and the school setting. Methods Participants were 553 children (age 9-11 years) attending 24 primary schools around Schiphol Amsterdam Airport. Cognitive performance was measured by the Neurobehavioral Evaluation System (NES), and a set of paper-and-pencil tests. Multilevel regression analyses were applied to estimate the association between noise exposure and cognitive performance, accounting for demographic and school related confounders. Results Effects of school noise exposure were observed in the more difficult parts of the Switching Attention Test (SAT): children attending schools with higher road or aircraft noise levels made significantly more errors. The correlational pattern and factor structure of the data indicate that the coherence between the neurobehavioral tests and paper-and-pencil tests is high. Conclusions Based on this study and previous scientific literature it can be concluded that performance on simple tasks is less susceptible to the effects of noise than performance on more complex tasks. PMID:20515466

  10. Finnish occupational health nurses' view of work-related stress: a cross-sectional study.

    PubMed

    Kinnunen-Amoroso, Maritta; Liira, Juha

    2014-03-01

    Occupational stress at work has been increasingly recognized as a major risk factor for chronic disease and poor quality of work life among employees. The purpose of this study was to examine how occupational health nurses in Finland manage work-related stress. A descriptive cross-sectional study design was used with a sample of 354 Finnish occupational nurses who responded to the survey. No specific standardized tools to assess or handle work-related stress in occupational health services or their client companies were identified. Open-ended interviews together with burnout questionnaires were the most frequently used methods to assess the stress of employees. Interventions were directed at individual employees. A need for standardized stress assessment instruments and stress management by work organizations was found. Methods to cope with work-related stress should be developed by the occupational health team and companies' health resources departments to ensure the adoption of common protocols. Copyright 2014, SLACK Incorporated.

  11. Dispersion relations with crossing symmetry for {pi}{pi} D- and F-wave amplitudes

    SciTech Connect

    Kaminski, R.

    2011-04-01

    A set of once subtracted dispersion relations with imposed crossing symmetry condition for the {pi}{pi} D- and F-wave amplitudes is derived and analyzed. An example of numerical calculations in the effective two-pion mass range from the threshold to 1.1 GeV is presented. It is shown that these new dispersion relations impose quite strong constraints on the analyzed {pi}{pi} interactions and are very useful tools to test the {pi}{pi} amplitudes. One of the goals of this work is to provide a complete set of equations required for easy use. Full analytical expressions are presented. Along with the well-known dispersion relations successful in testing the {pi}{pi} S- and P-wave amplitudes, those presented here for the D and F waves give a complete set of tools for analyses of the {pi}{pi} interactions.

  12. Development of aerobic power in relation to age and training in cross-country skiers.

    PubMed

    Rusko, H K

    1992-09-01

    In most of the training studies on different populations the effects of training have been investigated up to a frequency of five to six times per week and a duration of 45 min per session. These correspond to the training regimens of 15-yr-old cross-country skiers and, consequently, the results cannot be applied to older athletes. The maximal oxygen uptake (VO2max) of cross-country skiers increases with age and training from about 55-60 to 75-80 ml.kg-1.min-1 between 15 and 25 yr of age. After 20 yr of age VO2max starts to level off, but elite skiers are able to increase VO2max further concomitantly with an increase in the volume of training and the volume of intensive training. The activity of oxidative enzymes in muscles of skiers is increased with training, but distance runners have had a higher oxidative capacity in their leg muscles. Although widely used by cross-country skiers, the training effects of roller skiing, skiwalking-skistriding, and long-distance training on skis are to a large extent unknown. However, intensive training at the intensity of "anaerobic threshold" or higher seems to be most effective in inducing improvements in maximal oxygen uptake; distance training at relatively low intensity seems to be most effective in producing improvements in the determinants of submaximal endurance.

  13. Predicting organic hydrogen atom transfer rate constants using the Marcus cross relation

    PubMed Central

    Warren, Jeffrey J.; Mayer, James M.

    2010-01-01

    Chemical reactions that involve net hydrogen atom transfer (HAT) are ubiquitous in chemistry and biology, from the action of antioxidants to industrial and metalloenzyme catalysis. This report develops and validates a procedure to predict rate constants for HAT reactions of oxyl radicals (RO•) in various media. Our procedure uses the Marcus cross relation (CR) and includes adjustments for solvent hydrogen-bonding effects on both the kinetics and thermodynamics of the reactions. Kinetic solvent effects (KSEs) are included by using Ingold’s model, and thermodynamic solvent effects are accounted for by using an empirical model developed by Abraham. These adjustments are shown to be critical to the success of our combined model, referred to as the CR/KSE model. As an initial test of the CR/KSE model we measured self-exchange and cross rate constants in different solvents for reactions of the 2,4,6-tri-tert-butylphenoxyl radical and the hydroxylamine 2,2′-6,6′-tetramethyl-piperidin-1-ol. Excellent agreement is observed between the calculated and directly determined cross rate constants. We then extend the model to over 30 known HAT reactions of oxyl radicals with OH or CH bonds, including biologically relevant reactions of ascorbate, peroxyl radicals, and α-tocopherol. The CR/KSE model shows remarkable predictive power, predicting rate constants to within a factor of 5 for almost all of the surveyed HAT reactions. PMID:20215463

  14. Why are there different age relations in cross-sectional and longitudinal comparisons of cognitive functioning?

    PubMed Central

    Salthouse, Timothy A.

    2014-01-01

    A major challenge for researchers interested in investigating relations between aging and cognitive functioning is distinguishing influences of aging from other determinants of cognitive performance. For example, cross-sectional comparisons may be distorted because people of different ages were born and grew up in different time periods, and longitudinal comparisons may be distorted because performance on a second occasion is influenced by the experience of performing the tests on the first occasion. One way in which these different types of influences might be investigated is with research designs involving comparisons of people of different ages from the same birth cohorts who are all tested for the first time in different years. Results from several recent studies using these types of designs suggest that the age trends in some cognitive abilities more closely resemble those from cross-sectional comparisons than those from longitudinal comparisons. These findings imply that a major reason for different age trends in longitudinal and cross-sectional comparisons of cognitive functioning is that the prior experience with the tests inflates scores on the second occasion in longitudinal studies. PMID:25382943

  15. Masked Cross-Modal Repetition Priming: An Event-Related Potential Investigation

    PubMed Central

    Kiyonaga, Kristi; Grainger, Jonathan; Midgley, Katherine; Holcomb, Phillip J.

    2007-01-01

    We report three experiments that combine the masked priming paradigm with the recording of event-related potentials in order to examine the time-course of cross-modal interactions during word recognition. Visually presented masked primes preceded either visually or auditorily presented targets that were or were not the same word as the prime. Experiment 1 used the lexical decision task, and in Experiments 2 and 3 participants monitored target words for animal names. The results show a strong modulation of the N400 and an earlier ERP component (N250 ms) in within-modality (visual-visual) repetition priming, and a much weaker and later N400-like effect (400–700 ms) in the cross-modal (visual-auditory) condition with prime exposures of 50 ms (Experiments 1 & 2). With a prime duration of 67 ms (Experiment 3), cross-modal ERP priming effects arose earlier during the traditional N400 epoch (300–500 ms) and were also larger overall than at the shorter prime duration. PMID:18163153

  16. Wheat and maize thioredoxins: a novel cross-reactive cereal allergen family related to baker's asthma.

    PubMed

    Weichel, Michael; Glaser, Andreas G; Ballmer-Weber, Barbara K; Schmid-Grendelmeier, Peter; Crameri, Reto

    2006-03-01

    Baker's asthma is a serious problem for a significant proportion of workers in bakeries, confectionaries, and the food industry. Although several wheat allergens related to baker's asthma have been described, standardized reagents for a reliable diagnosis are not yet available. To clone novel wheat allergens related to baker's asthma and investigate the cross-reactive potential of their maize and human homologues. A wheat cDNA phage display library was screened with sera from bakers with occupational asthma for IgE-binding structures. Homologous sequences from maize and human thioredoxins were amplified from corresponding cDNA libraries. Within the enriched wheat cDNA repertoire we identified, among others, the sequence encoding wheat thioredoxin-hB (Triticum aestivum allergen 25 [Tri a 25]). The recombinant protein displayed enzymatic activity, and we observed a sensitization rate of 47% among bakers with occupational asthma and of 35% among patients with grass pollen allergy, but without a clinical history of cereal allergy. Furthermore, the previously characterized maize thioredoxin-h1 (Zea mays allergen 25 [Zea m 25]), sharing 74% identity with Tri a 25, exhibited distinct IgE cross-reactivity with its wheat homologue. Two bakers also showed sensitization to human thioredoxin, which shares 29% identity with Tri a 25. In a comparative study, we included recombinant alpha-amylase inhibitor 0.19, showing a sensitization rate of 65% in individuals with baker's asthma. Thioredoxins represent a novel family of cross-reactive allergens that might contribute to the symptoms of baker's asthma and might in addition be related to grass pollen allergy, as indicated by the reactivity of grass pollen allergic patients to cereal thioredoxins. The recombinant cereal thioredoxins will, together with the already reported wheat allergens, contribute to a more reliable diagnosis of baker's asthma and, perhaps, become a tool for the development of component-resolved immunotherapy.

  17. Age-related changes in auditory processing and speech perception: cross-sectional and longitudinal analyses.

    PubMed

    Babkoff, Harvey; Fostick, Leah

    2017-09-01

    Age-related differences in speech perception have been shown in previous cross-sectional studies to be related to auditory temporal processing. We examined this association in both cross-sectional and longitudinal designs, controlling for age-related changes in hearing sensitivity and cognitive ability. Fifty-eight participants were tested in two phases. In phase 1, ages ranged between 22 and 82 years. Phase 2 occurred seven years later. In both phases, participants performed auditory processing tasks, speech perception tests, and cognitive tasks. In both phases, age correlated with hearing level, auditory temporal processing thresholds, word recognition accuracy in noise, and compressed speech. Auditory temporal processing thresholds were correlated with word recognition accuracy in narrowband noise and compressed speech. Longitudinal analysis showed significant decreases in performance from phase 1 to phase 2 in hearing level, dichotic TOJ thresholds, and word recognition accuracy. Steeper slopes were observed in phase 2 than in phase 1 for correlations between age, hearing level, and word recognition accuracy in narrowband noise, but not for age and dichotic TOJ thresholds. Generalized estimating equations revealed an overall decrease in word recognition accuracy from phase 1 to phase 2; this decrease was larger for older participants. Increases in dichotic TOJ and gap detection thresholds were associated with a decrease over time in speech in narrowband and broadband noise, and compressed speech, even when adjusted for age, hearing level, and cognitive ability. These results show that both cross-sectional and longitudinal designs yield similar significant associations between temporal processing and speech perception, even when adjusted for hearing level and cognitive ability.

  18. Oral Hygiene Practices and Dentition Status of Public Transport Workers of India- A Cross-sectional Study

    PubMed Central

    Sohi, Ramandeep Kaur; Singh, Gurminder; Brar, Rajdeep; Singh, Harpreet; Kakar, Heena

    2014-01-01

    Objectives: To evaluate the oral hygiene practices and dentition statuses of transport workers who were working in a public bus transport system (C.T.U.) of Chandigarh (U.T.), India. Materials and Methods: The data were recorded on a modified W.H.O. format (1997). A total of 1008 subjects constituted the final sample size. Information was obtained regarding the oral hygiene practices and clinical examinations were conducted. Statistical analysis was done by using ANOVA and Z-test. Results: The mean age of the subjects was 45.3 ± 7.8 years. Mean DMFT of the subjects who were not using tobacco in any form was 5.02. 80.2% (808). 88.7% of the subjects brushed their teeth as least once a day. Mean number of decayed and missing teeth were 1.67 ± 2.16 and 1.46 ± 2.8, respectively and their relation with age was found to be statistically significant. Conclusion: Dental caries was found to be major indication in all the age groups. More elderly subjects than young needed extractions. This study emphasized the need of an improved dental awareness and availability of dental facilities to transport workers. PMID:25386518

  19. Topologically Conserved Residues Direct Heme Transport in HRG-1-related Proteins*

    PubMed Central

    Yuan, Xiaojing; Protchenko, Olga; Philpott, Caroline C.; Hamza, Iqbal

    2012-01-01

    Caenorhabditis elegans and human HRG-1-related proteins are conserved, membrane-bound permeases that bind and translocate heme in metazoan cells via a currently uncharacterized mechanism. Here, we show that cellular import of heme by HRG-1-related proteins from worms and humans requires strategically located amino acids that are topologically conserved across species. We exploit a heme synthesis-defective Saccharomyces cerevisiae mutant to model the heme auxotrophy of C. elegans and demonstrate that, under heme-deplete conditions, the endosomal CeHRG-1 requires both a specific histidine in the predicted second transmembrane domain (TMD2) and the FARKY motif in the C terminus tail for heme transport. By contrast, the plasma membrane CeHRG-4 transports heme by utilizing a histidine in the exoplasmic (E2) loop and the FARKY motif. Optimal activity under heme-limiting conditions, however, requires histidine in the E2 loop of CeHRG-1 and tyrosine in TMD2 of CeHRG-4. An analogous system exists in humans, because mutation of the synonymous histidine in TMD2 of hHRG-1 eliminates heme transport activity, implying an evolutionary conserved heme transport mechanism that predates vertebrate origins. Our results support a model in which heme is translocated across membranes facilitated by conserved amino acids positioned on the exoplasmic, cytoplasmic, and transmembrane regions of HRG-1-related proteins. These findings may provide a framework for understanding the structural basis of heme transport in eukaryotes and human parasites, which rely on host heme for survival. PMID:22174408

  20. Gene expression of carnosine-related enzymes and transporters in skeletal muscle.

    PubMed

    Everaert, Inge; De Naeyer, Hélène; Taes, Youri; Derave, Wim

    2013-05-01

    Chronic oral beta-alanine supplementation can elevate muscle carnosine (beta-alanyl-L-histidine) content and improve high-intensity exercise performance. However, the regulation of muscle carnosine levels is poorly understood. The uptake of the rate-limiting precursor beta-alanine and the enzyme catalyzing the dipeptide synthesis are thought to be key steps. The aims of this study were to investigate the expression of possible carnosine-related enzymes and transporters in both human and mouse skeletal muscle in response to carnosine-altering stimuli. Human gastrocnemius lateralis and mouse tibialis anterior muscle samples were subjected to HPLC and qPCR analysis. Mice were subjected to chronic oral supplementation of beta-alanine and carnosine or to orchidectomy (7 and 30 days, with or without testosterone replacement), stimuli known to, respectively, increase and decrease muscle carnosine and anserine. The following carnosine-related enzymes and transporters were expressed in human and/or mouse muscles: carnosine synthase (CARNS), carnosinase-2 (CNDP2), the carnosine/histidine transporters PHT1 and PHT2, the beta-alanine transporters TauT and PAT1, beta-alanine transaminase (ABAT) and histidine decarboxylase (HDC). Six of these genes showed altered expression in the investigated interventions. Orchidectomy led to decreased muscle carnosine content, which was paralleled with decreased TauT expression, whereas CARNS expression was surprisingly increased. Beta-alanine supplementation increased both muscle carnosine content and TauT, CARNS and ABAT expression, suggesting that muscles increase beta-alanine utilization through both dipeptide synthesis (CARNS) and deamination (ABAT) and further oxidation, in conditions of excess availability. Collectively, these data show that muscle carnosine homeostasis is regulated by nutritional and hormonal stimuli in a complex interplay between related transporters and enzymes.

  1. The initiation, propagation, and effect of matrix microcracks in cross-ply and related laminates

    NASA Technical Reports Server (NTRS)

    Nairn, John A.; Hu, Shoufeng; Liu, Siulie; Bark, Jong

    1991-01-01

    Recently, a variational mechanics approach was used to determine the thermoelastic stress state in cracked laminates. Described here is a generalization of the variational mechanics techniques to handle other cross-ply laminates, related laminates, and to account for delaminations emanating from microcrack tips. Microcracking experiments on Hercules 3501-6/AS4 carbon fiber/epoxy laminates show a staggered cracking pattern. These results can be explained by the variational mechanics analysis. The analysis of delaminations emanating from microcrack tips has resulted in predictions about the structural and material variables controlling competition between microcracking and delamination failure modes.

  2. Foreign currency-related translation complexities in cross-border healthcare applications.

    PubMed

    Kumar, Anand; Rodrigues, Jean M

    2009-01-01

    International cross-border private hospital chains need to apply the standards for foreign currency translation in order to consolidate the balance sheet and income statements. This not only exposes such chains to exchange rate fluctuations in different ways, but also creates added requirements for enterprise-level IT systems especially when they produce parameters which are used to measure the financial and operational performance of the foreign subsidiary or the parent hospital. Such systems would need to come to terms with the complexities involved in such currency-related translations in order to provide the correct data for performance benchmarking.

  3. Data linkage infrastructure for cross-jurisdictional health-related research in Australia

    PubMed Central

    2012-01-01

    Background The Centre for Data Linkage (CDL) has been established to enable national and cross-jurisdictional health-related research in Australia. It has been funded through the Population Health Research Network (PHRN), a national initiative established under the National Collaborative Research Infrastructure Strategy (NCRIS). This paper describes the development of the processes and methodology required to create cross-jurisdictional research infrastructure and enable aggregation of State and Territory linkages into a single linkage “map”. Methods The CDL has implemented a linkage model which incorporates best practice in data linkage and adheres to data integration principles set down by the Australian Government. Working closely with data custodians and State-based data linkage facilities, the CDL has designed and implemented a linkage system to enable research at national or cross-jurisdictional level. A secure operational environment has also been established with strong governance arrangements to maximise privacy and the confidentiality of data. Results The development and implementation of a cross-jurisdictional linkage model overcomes a number of challenges associated with the federated nature of health data collections in Australia. The infrastructure expands Australia’s data linkage capability and provides opportunities for population-level research. The CDL linkage model, infrastructure architecture and governance arrangements are presented. The quality and capability of the new infrastructure is demonstrated through the conduct of data linkage for the first PHRN Proof of Concept Collaboration project, where more than 25 million records were successfully linked to a very high quality. Conclusions This infrastructure provides researchers and policy-makers with the ability to undertake linkage-based research that extends across jurisdictional boundaries. It represents an advance in Australia’s national data linkage capabilities and sets the scene

  4. Data linkage infrastructure for cross-jurisdictional health-related research in Australia.

    PubMed

    Boyd, James H; Ferrante, Anna M; O'Keefe, Christine M; Bass, Alfred J; Randall, Sean M; Semmens, James B

    2012-12-29

    The Centre for Data Linkage (CDL) has been established to enable national and cross-jurisdictional health-related research in Australia. It has been funded through the Population Health Research Network (PHRN), a national initiative established under the National Collaborative Research Infrastructure Strategy (NCRIS). This paper describes the development of the processes and methodology required to create cross-jurisdictional research infrastructure and enable aggregation of State and Territory linkages into a single linkage "map". The CDL has implemented a linkage model which incorporates best practice in data linkage and adheres to data integration principles set down by the Australian Government. Working closely with data custodians and State-based data linkage facilities, the CDL has designed and implemented a linkage system to enable research at national or cross-jurisdictional level. A secure operational environment has also been established with strong governance arrangements to maximise privacy and the confidentiality of data. The development and implementation of a cross-jurisdictional linkage model overcomes a number of challenges associated with the federated nature of health data collections in Australia. The infrastructure expands Australia's data linkage capability and provides opportunities for population-level research. The CDL linkage model, infrastructure architecture and governance arrangements are presented. The quality and capability of the new infrastructure is demonstrated through the conduct of data linkage for the first PHRN Proof of Concept Collaboration project, where more than 25 million records were successfully linked to a very high quality. This infrastructure provides researchers and policy-makers with the ability to undertake linkage-based research that extends across jurisdictional boundaries. It represents an advance in Australia's national data linkage capabilities and sets the scene for stronger government-research collaboration.

  5. Constitutive Relations for Reactive Transport Modeling: Effects of Chemical Reactions on Multi-Phase Flow Properties

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Liu, H. H.; van Dijke, M. I.; Geiger, S.; Agar, S. M.

    2016-12-01

    The relationship between flow properties and chemical reactions is key to modeling subsurface reactive transport. This study develops closed-form equations to describe the effects of mineral precipitation and dissolution on multiphase flow properties (capillary pressure and relative permeabilities) of porous media. The model accounts for the fact that precipitation/dissolution only takes place in the water-filled part of pore space. The capillary tube concept was used to connect pore-scale changes to macroscopic hydraulic properties. Precipitation/dissolution induces changes in the pore radii of water-filled pores and consequently in the pore-size distribution. The updated pore-size distribution is converted back to a new capillary pressure-water saturation relation from which the new relative permeabilities are calculated. Pore network modeling is conducted on a Berea sandstone to validate the new continuum-scale relations. The pore network modeling results are satisfactorily predicted by the new closed-form equations. Currently the effects of chemical reactions on flow properties are represented as a relation between permeability and porosity in reactive transport modeling. Porosity is updated after chemical calculations from the change of mineral volumes, then permeability change is calculated from the porosity change using an empirical permeability-porosity relation, most commonly the Carman-Kozeny relation, or the Verma-Pruess relation. To the best of our knowledge, there are no closed-form relations available yet for the effects of chemical reactions on multi-phase flow properties, and thus currently these effects cannot be accounted for in reactive transport modeling. This work presents new constitutive relations to represent how chemical reactions affect multi-phase flow properties on the continuum scale based on the conceptual model of parallel capillary tubes. The parameters in our new relations are either pre-existing input in a multi-phase flow

  6. Determining the Scope of Collection Development and Research Assistance for Cross-Disciplinary Areas: A Case Study of Two Contrasting Areas, Nanotechnology and Transportation Engineering

    ERIC Educational Resources Information Center

    Williamson, Jeanine M.; Han, Lee D.; Colon-Aguirre, Monica

    2009-01-01

    The study examined the extent of cross-disciplinarity in nanotechnology and transportation engineering research. Researchers in these two fields were determined from the web sites of the U.S. News and World Report top 100 schools in civil engineering and materials science. Web of Science searches for 2006 and 2007 articles were obtained and the…

  7. Determining the Scope of Collection Development and Research Assistance for Cross-Disciplinary Areas: A Case Study of Two Contrasting Areas, Nanotechnology and Transportation Engineering

    ERIC Educational Resources Information Center

    Williamson, Jeanine M.; Han, Lee D.; Colon-Aguirre, Monica

    2009-01-01

    The study examined the extent of cross-disciplinarity in nanotechnology and transportation engineering research. Researchers in these two fields were determined from the web sites of the U.S. News and World Report top 100 schools in civil engineering and materials science. Web of Science searches for 2006 and 2007 articles were obtained and the…

  8. International comparisons of the associations between objective measures of the built environment and transport-related walking and cycling: IPEN Adult Study.

    PubMed

    Christiansen, Lars B; Cerin, Ester; Badland, Hannah; Kerr, Jacqueline; Davey, Rachel; Troelsen, Jens; van Dyck, Delfien; Mitáš, Josef; Schofield, Grant; Sugiyama, Takemi; Salvo, Deborah; Sarmiento, Olga L; Reis, Rodrigo; Adams, Marc; Frank, Larry; Sallis, James F

    2016-12-01

    Mounting evidence documents the importance of urban form for active travel, but international studies could strengthen the evidence. The aim of the study was to document the strength, shape, and generalizability of relations of objectively measured built environment variables with transport-related walking and cycling. This cross-sectional study maximized variation of environments and demographics by including multiple countries and by selecting adult participants living in neighborhoods based on higher and lower classifications of objectively measured walkability and socioeconomic status. Analyses were conducted on 12,181 adults aged 18-66 years, drawn from 14 cities across 10 countries worldwide. Frequency of transport-related walking and cycling over the last seven days was assessed by questionnaire and four objectively measured built environment variables were calculated. Associations of built environment variables with transport-related walking and cycling variables were estimated using generalized additive mixed models, and were tested for curvilinearity and study site moderation. We found positive associations of walking for transport with all the environmental attributes, but also found that the relationships was only linear for land use mix, but not for residential density, intersection density, and the number of parks. Our findings suggest that there may be optimum values in these attributes, beyond which higher densities or number of parks could have minor or even negative impact. Cycling for transport was associated linearly with residential density, intersection density (only for any cycling), and land use mix, but not with the number of parks. Across 14 diverse cities and countries, living in more densely populated areas, having a well-connected street network, more diverse land uses, and having more parks were positively associated with transport-related walking and/or cycling. Except for land-use-mix, all built environment variables had curvilinear

  9. Health-related quality of life and related factors among elderly people in Jinzhou, China: a cross-sectional study.

    PubMed

    Dai, H; Jia, G; Liu, K

    2015-06-01

    With rapid reductions in fertility and mortality, China has to face the dramatic ageing of its population. Although an ageing population is associated with greater life expectancy, and reflects a huge improvement in people's living standards and health care services, it also means that more elderly people suffer from non-communicable diseases (NCDs). The prolonged course of illness and disability associated with chronic diseases may significantly reduce health-related quality of life (HRQoL) among elderly people. The aims of this study were to evaluate HRQoL of elderly people living in Jinzhou, and to identify the predictors of HRQoL. Cross-sectional study with stratified sampling. A cross-sectional survey was conducted among 1015 elderly people (≥60 years) living in the three administrative regions (Linghe, Guta and Taihe) of Jinzhou. A demographic questionnaire and Short Form-36 were employed to collect demographic variables and evaluate HRQoL, respectively. Multiple stepwise linear regression analysis was performed to estimate factors related to HRQoL of the subjects. Lowest HRQoL scores were obtained in the following dimensions: general health (65.44), role-emotional (69.74) and role-physical (70.20). Multiple stepwise regression showed that factors associated with HRQoL of elderly people were medical health checks, age, socio-economic status, NCDs, and various unhealthy lifestyle behaviours such as smoking, excessive drinking and insufficient exercise. This study described overall HRQoL of elderly people in Jinzhou, and found that medical health checks, age, socio-economic status, NCDs, smoking, excessive drinking and insufficient exercise affected HRQoL. These findings will provide a basis for recommendations regarding health management of elderly people, and will also help local government to devise appropriate health intervention strategies for promoting the health status of elderly people in this region. Copyright © 2015 The Royal Society for Public

  10. Ion collision cross sections and transport coefficients extended to intermediate energies and reduced electric fields for He2+ ions colliding with He

    NASA Astrophysics Data System (ADS)

    Chicheportiche, A.; Benhenni, M.; Yousfi, M.; Lepetit, B.; Kalus, R.; Gadea, F. X.

    2013-10-01

    This work is devoted to the calculation of transport coefficients for He2+ ions in gaseous He at intermediate reduced electric fields. These swarm data are of great interest for a better understanding of the mechanisms of formation and propagation of the fast plasma bullets or ionization waves observed in dielectric barrier plasma jet devices. For transport data, the collision cross sections required are determined from several theoretical methods based on quantum, semiclassical, and hybrid approaches and a diatomics-in-molecules model for the potential energy surfaces of He3+. The corresponding collision cross sections are then used in an optimized Monte Carlo code to calculate the ion transport coefficients over a wide range of reduced electric fields extending over the experimental range. Calculated transport coefficients are compared with available experimental data at low electric fields. Moreover, an extrapolation method is used in order to determine the reduced mobility for stronger fields. A critical discussion has been performed on the pertinence and the reliability of these different methods of determination of collision cross sections needed for the calculation of ion transport data. Such ion data will be used in electrohydrodynamic and chemical kinetic models of the low-temperature plasma jet to quantify and to tune the active species production for a better use in biomedical applications.

  11. Determination of O₂ Mass Transport at the Pt | PFSA Ionomer Interface under Reduced Relative Humidity.

    PubMed

    Novitski, David; Holdcroft, Steven

    2015-12-16

    Oxygen mass transport resistance through the ionomer component in the cathode catalyst layer is considered to contribute overpotential losses in polymer electrolyte membrane fuel cells. Whereas it is known that water uptake, water transport, and proton conductivity are reduced upon reducing relative humidity, the effect on oxygen mass transport remains unknown. We report a two-electrode approach to determine mass transport coefficients for the oxygen reduction reaction in air at the Pt/perfluorosulfonic acid ionomer membrane interface between 90 and 30% RH at 70 °C using a Pt microdisk in a solid state electrochemical cell. Potential-step chronoamperometry was performed at specific mass-transport limiting potentials to allow for the elucidation of the oxygen diffusion coefficient (D(bO2)) and oxygen concentration (c(bO2)). In our efforts, novel approaches in data acquisition, as well as analysis, were examined because of the dynamic nature of the membrane under lowered hydration conditions. Linear regression analysis reveals a decrease in oxygen permeability (D(bO2c(bO2)) by a factor of 1.7 and 3.4 from 90 to 30% RH for Nafion 211 membrane and membranes cast from Nafion DE2020 ionomer solutions, respectively. Additionally, nonlinear curve fitting by way of the Shoup-Szabo equation is employed to analyze the entire current transient during potential step controlled ORR. We also report on the presence of an RH dependence of our previously reported time-dependency measurements for O2 mass transport coefficients.

  12. Alveolar macrophages from normal subjects lack the NOS-related system y+ for arginine transport.

    PubMed

    Rotoli, Bianca Maria; Dall'asta, Valeria; Barilli, Amelia; D'Ippolito, Raffaele; Tipa, Annalisa; Olivieri, Dario; Gazzola, Gian C; Bussolati, Ovidio

    2007-07-01

    Systems y+ and y+L represent the main routes for arginine transport in mammalian cells. While system y+ activity is needed for the stimulated NO production in rodent alveolar macrophages (AM), no information is yet available about arginine transport in human AM. We study here arginine influx and genes for arginine transporters in AM from bronchoalveolar lavage of normal subjects. These cells express the y+ -related genes SLC7A1/CAT1 and SLC7A2/CAT2B, as well as the y+L genes SLC7A7/y+LAT1 and SLC7A6/y+LAT2. However, compared with human endothelial cells, AM express much less SLC7A2 mRNA and higher levels of SLC7A7 mRNA. Granulocyte macrophage colony-stimulating factor or IFN-gamma do not change the expression of any transporter gene, while lipopolysaccharide induces SLC7A2/CAT2B. Under all the conditions tested, leucine inhibits most of the arginine transport in the presence of Na+ and N-ethylmaleimide, an inhibitor of system y+, is completely ineffective, indicating that system y+L operates most of the arginine influx. Comparable results are obtained in AM from patients with interstitial lung disease, such as Nonspecific Interstitial Pneumonia (NSIP), although these cells have a higher SLC7A1 and a lower SLC7A7 expression than AM from normal subjects. It is concluded that AM from normal subjects or patients with NSIP lack a functional transport system y+, a situation that may limit arginine availability for NO synthesis. Moreover, since mutations of SLC7A7/y+LAT1 cause Lysinuric Protein Intolerance, a disease often associated with AM impairment and alveolar proteinosis, the high SLC7A7 expression observed in human AM suggests that y+LAT1 activity is important for the function of these cells.

  13. OSBP-Related Protein Family: Mediators of Lipid Transport and Signaling at Membrane Contact Sites.

    PubMed

    Kentala, Henriikka; Weber-Boyvat, Marion; Olkkonen, Vesa M

    2016-01-01

    Oxysterol-binding protein (OSBP) and its related protein homologs, ORPs, constitute a conserved family of lipid-binding/transfer proteins (LTPs) expressed ubiquitously in eukaryotes. The ligand-binding domain of ORPs accommodates cholesterol and oxysterols, but also glycerophospholipids, particularly phosphatidylinositol-4-phosphate (PI4P). ORPs have been implicated as intracellular lipid sensors or transporters. Most ORPs carry targeting determinants for the endoplasmic reticulum (ER) and non-ER organelle membrane. ORPs are located and function at membrane contact sites (MCSs), at which ER is closely apposed with other organelle limiting membranes. Such sites have roles in lipid transport and metabolism, control of Ca(2+) fluxes, and signaling events. ORPs are postulated either to transport lipids over MCSs to maintain the distinct lipid compositions of organelle membranes, or to control the activity of enzymes/protein complexes with functions in signaling and lipid metabolism. ORPs may transfer PI4P and another lipid class bidirectionally. Transport of PI4P followed by its hydrolysis would in this model provide the energy for transfer of the other lipid against its concentration gradient. Control of organelle lipid compositions by OSBP/ORPs is important for the life cycles of several pathogenic viruses. Targeting ORPs with small-molecular antagonists is proposed as a new strategy to combat viral infections. Several ORPs are reported to modulate vesicle transport along the secretory or endocytic pathways. Moreover, antagonists of certain ORPs inhibit cancer cell proliferation. Thus, ORPs are LTPs, which mediate interorganelle lipid transport and coordinate lipid signals with a variety of cellular regimes. Copyright © 2016. Published by Elsevier Inc.

  14. Advanced subsonic transport approach noise: The relative contribution of airframe noise

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr.; Garber, Donald P.

    1992-01-01

    With current engine technology, airframe noise is a contributing source for large commercial aircraft on approach, but not the major contributor. With the promise of much quieter jet engines with the planned new generation of high-by-pass turbofan engines, airframe noise has become a topic of interest in the advanced subsonic transport research program. The objective of this paper is to assess the contribution of airframe noise relative to the other aircraft noise sources on approach. The assessment will be made for a current technology large commercial transport aircraft and for an envisioned advanced technology aircraft. NASA's Aircraft Noise Prediction Program (ANOPP) will be used to make total aircraft noise predictions for these two aircraft types. Predicted noise levels and areas of noise contours will be used to determine the relative importance of the contributing approach noise sources. The actual set-up decks used to make the ANOPP runs for the two aircraft types are included in appendixes.

  15. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions. Significant effects of gravity vector orientation on the growth crystal morphology and point defect distribution were observed.

  16. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions. Significant effects of gravity vector orientation on the growth crystal morphology and point defect distribution were observed.

  17. Body weight concerns: Cross-national study and identification of factors related to eating disorders.

    PubMed

    Silva, Wanderson Roberto da; Santana, Moema de Souza; Maroco, João; Maloa, Benvindo Felismino Samuel; Campos, Juliana Alvares Duarte Bonini

    2017-01-01

    Body weight concerns are common among individuals with eating disorders, and this construct can be assessed using psychometric instruments. The Weight Concerns Scale (WCS) is commonly used to assess body weight concerns. To evaluate the psychometric properties of the WCS with Brazilian, Portuguese, and Mozambican female college students; to estimate body weight concerns; and to identify factors related to eating disorders. Confirmatory factor analysis was performed. Factorial, convergent, concurrent, and divergent validity, as well as reliability, were assessed. Cross-national invariance was tested by means of multigroup analysis. Structural models were tested using the WCS as the dependent variable, while demographic and academic variables and body mass index were used as independent variables. Logistic models were tested to estimate the likelihood of eating disorders being developed in specific groups. Participants were 2,068 female students. The psychometric properties of the WCS were adequate for the Portuguese sample; however, for the Brazilian and Mozambican samples, it was necessary to correlate the errors of two items to improve model fit. The WCS did not show cross-national invariance. The variables "thoughts about dropping out of college," "medication use because of studies," "medication and supplements use for body change," "body mass index," "socioeconomic status," "age," and "performance in course" were significant predictors of body weight concerns. Overall, 24.4% (95% confidence interval = 22.9-26.7) of the students were likely to develop eating disorders. Students under 21 years old, who use medication and supplements for body change, and who were classified as overweight/obese have increased likelihood of developing eating disorders. The WCS showed good psychometric properties with Brazilian, Portuguese, and Mozambican students; however, it did not show cross-national invariance. We identified important aspects for investigating body weight

  18. Towards an explanation of age-related difficulties in crossing a two-way street.

    PubMed

    Dommes, Aurélie; Lay, Tristan Le; Vienne, Fabrice; Dang, Nguyen-Thong; Beaudoin, Alexandra Perrot; Do, Manh Cuong

    2015-12-01

    Crossing a two-way street is a complex task that involves visual, cognitive and motor abilities, all of which are known to decline with ageing. In particular, older pedestrians may experience difficulties when crossing two-way streets because of incorrect gap acceptance choices and impossible or unperceived evasive actions. To understand the overrepresentation of older pedestrians in crash statistics, several experimental studies have sought to identify traffic-related factors as well as those related to the abilities of the individuals themselves. However, none of these studies has required participants to actually walk across an experimental two-way street with curbs, which is a particularly challenging situation for older pedestrians. To fill this research gap, a quasi-experiment was conducted in a simulator including a total of 58 healthy aged participants (25 younger-old [age 60-72] and 33 older-old [age 72-92]) and 25 young adults (aged 18-25 years). Participants carried out a street-crossing task in a simulated two-way traffic environment; curbs were present on both sides of the experimental street. Participants also undertook a battery of tests to assess their visual and cognitive abilities. In addition, during the experiment, the participants' gait parameters were recorded. In line with earlier findings, the older-old group of participants made a higher number of decisions that led to collisions with approaching cars compared with the other groups. The two groups of older participants experienced specific difficulties when vehicles were in the far lane or when they approached rapidly. A regression analysis identified visual acuity, speed of processing (assessed using the UFOV(®) test), and step length as significant predictors of collisions. Our results have implications for understanding the difficulties experienced by older pedestrians and allow to draw up several recommendations for improving their safety.

  19. Resonance charge transfer, transport cross sections, and collision integrals for N(+)(3P)-N(4S0) and O(+)(4S0)-O(3P) interactions

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene

    1991-01-01

    N2(+) and O2(+) potential energy curves have been constructed by combining measured data with the results from electronic structure calculations. These potential curves have been employed to determine accurate charge exchange cross sections, transport cross sections, and collision integrals for ground state N(+)-N and O(+)-O interactions. The cross sections have been calculated from a semiclassical approximation to the scattering using a computer code that fits a spline curve through the discrete potential data and incorporates the proper long-range behavior of the interactions forces. The collision integrals are tabulated for a broad range of temperatures 250-100,000 K and are intended to reduce the uncertainty in the values of the transport properties of nonequilibrium air, particularly at high temperatures.

  20. One-dimensional deterministic transport in neurons measured by dispersion-relation phase spectroscopy

    PubMed Central

    Wang, Ru; Wang, Zhuo; Leigh, Joe; Sobh, Nahil; Millet, Larry; Gillette, Martha U.; Levine, Alex J.; Popescu, Gabriel

    2011-01-01

    We studied the active transport of intracellular components along neuron processes with a new method developed in our laboratory, dispersion-relation phase spectroscopy. This method is able to quantitatively map spatially the heterogeneous dynamics of the concentration field of the cargos at submicron resolution without the need for tracking individual components. The results in terms of density correlation function reveal that the decay rate is linear in wavenumber, which is consistent with a narrow Lorentzian distribution of cargo velocity. PMID:21862838

  1. Relative deprivation, poverty, and subjective health: JAGES cross-sectional study.

    PubMed

    Saito, Masashige; Kondo, Katsunori; Kondo, Naoki; Abe, Aya; Ojima, Toshiyuki; Suzuki, Kayo

    2014-01-01

    To evaluate the association between relative deprivation (lacking daily necessities) and subjective health in older Japanese adults, we performed a cross-sectional analysis using data from the Japan Gerontological Evaluation Study (JAGES). The data were obtained from functionally independent residents aged ≥65 years from 24 municipalities in Japan (n = 24,742). Thirteen items in three dimensions were used to evaluate relative deprivation of material conditions. Approximately 28% of older Japanese people indicated that they lacked some daily necessities (non-monetary poverty). A two-level Poisson regression analysis revealed that relative deprivation was associated with poor self-rated health (PR = 1.3-1.5) and depressive symptoms (PR = 1.5-1.8) in both men and women, and these relationships were stronger than those observed in people living in relative poverty (monetary poverty). The interaction effect between relative deprivation and relative poverty was not associated with poor health. As a dimension of the social determinants of health, poverty should be evaluated from a multidimensional approach, capturing not only monetary conditions but also material-based, non-monetary conditions.

  2. Relative Deprivation, Poverty, and Subjective Health: JAGES Cross-Sectional Study

    PubMed Central

    Saito, Masashige; Kondo, Katsunori; Kondo, Naoki; Abe, Aya; Ojima, Toshiyuki; Suzuki, Kayo

    2014-01-01

    To evaluate the association between relative deprivation (lacking daily necessities) and subjective health in older Japanese adults, we performed a cross-sectional analysis using data from the Japan Gerontological Evaluation Study (JAGES). The data were obtained from functionally independent residents aged ≥65 years from 24 municipalities in Japan (n = 24,742). Thirteen items in three dimensions were used to evaluate relative deprivation of material conditions. Approximately 28% of older Japanese people indicated that they lacked some daily necessities (non-monetary poverty). A two-level Poisson regression analysis revealed that relative deprivation was associated with poor self-rated health (PR = 1.3–1.5) and depressive symptoms (PR = 1.5–1.8) in both men and women, and these relationships were stronger than those observed in people living in relative poverty (monetary poverty). The interaction effect between relative deprivation and relative poverty was not associated with poor health. As a dimension of the social determinants of health, poverty should be evaluated from a multidimensional approach, capturing not only monetary conditions but also material-based, non-monetary conditions. PMID:25350284

  3. Phosphate transporters in marine phytoplankton and their viruses: cross-domain commonalities in viral-host gene exchanges.

    PubMed

    Monier, Adam; Welsh, Rory M; Gentemann, Chelle; Weinstock, George; Sodergren, Erica; Armbrust, E Virginia; Eisen, Jonathan A; Worden, Alexandra Z

    2012-01-01

    Phosphate (PO(4)) is an important limiting nutrient in marine environments. Marine cyanobacteria scavenge PO(4) using the high-affinity periplasmic phosphate binding protein PstS. The pstS gene has recently been identified in genomes of cyanobacterial viruses as well. Here, we analyse genes encoding transporters in genomes from viruses that infect eukaryotic phytoplankton. We identified inorganic PO(4) transporter-encoding genes from the PHO4 superfamily in several virus genomes, along with other transporter-encoding genes. Homologues of the viral pho4 genes were also identified in genome sequences from the genera that these viruses infect. Genome sequences were available from host genera of all the phytoplankton viruses analysed except the host genus Bathycoccus. Pho4 was recovered from Bathycoccus by sequencing a targeted metagenome from an uncultured Atlantic Ocean population. Phylogenetic reconstruction showed that pho4 genes from pelagophytes, haptophytes and infecting viruses were more closely related to homologues in prasinophytes than to those in what, at the species level, are considered to be closer relatives (e.g. diatoms). We also identified PHO4 superfamily members in ocean metagenomes, including new metagenomes from the Pacific Ocean. The environmental sequences grouped with pelagophytes, haptophytes, prasinophytes and viruses as well as bacteria. The analyses suggest that multiple independent pho4 gene transfer events have occurred between marine viruses and both eukaryotic and bacterial hosts. Additionally, pho4 genes were identified in available genomes from viruses that infect marine eukaryotes but not those that infect terrestrial hosts. Commonalities in marine host-virus gene exchanges indicate that manipulation of host-PO(4) uptake is an important adaptation for viral proliferation in marine systems. Our findings suggest that PO(4) -availability may not serve as a simple bottom-up control of marine phytoplankton.

  4. Relative location using waveform cross correlation: comparison of the Aitik and Kiruna mines

    NASA Astrophysics Data System (ADS)

    Rozhkov, Mikhail; Bobrov, Dmitry; Kitov, Ivan; Yedlin, Matthew

    2017-04-01

    Waveform cross correlation (WCC) is a powerful tool of signal detection from repeated events like mining blasts. In this study, we use seismic data measured at four array stations (ARCES, FINES, NOA, and HFS) of the International Monitoring System (IMS) from two quarries in Sweden - the Aitik copper and Kiruna iron mines. Both mines are characterized by intensive blasting practice, with hundreds of blasts found by the International Data Centre and available in its Reviewed Events Bulletin. In our previous study, we applied the WCC method to these repeated signals and estimated the overall similarity of signals at one mine and between mines. In order to provide the best use of the whole multitude of historical events and to reduce the number of waveform templates needed for comprehensive signal detection and association, we applied several high-order factorization techniques to the tensor based representation of seismic array data, so the lower order tensor construction was used as synthetic waveform template set. As a result, we found that signals from two mines might correlate and the only reliable method to actually distinguish between blasts conducted at the Aitik and Kiruna mines is to locate them using arrival times obtained by cross correlation. Here, we present select results of detection, relative location and mine identification as obtained since the end of 2016. This is an out-of-sample test of the procedures related to the WCC method.

  5. Microsatellite primers for Camissoniopsis cheiranthifolia (Onagraceae) and cross-amplification in related species1

    PubMed Central

    López-Villalobos, Adriana; Samis, Karen E.; Eckert, Christopher G.

    2014-01-01

    • Premise of the study: We developed 24 nuclear microsatellite primers from an enriched genomic library for the Pacific coastal dune endemic Camissoniopsis cheiranthifolia to study the consequences of mating system differentiation, the genetics of species’ range limits, and hybridization with its closest sister taxon, C. bistorta. • Methods and Results: Twenty-four primer pairs were developed and characterized in four populations of C. cheiranthifolia and one population of C. bistorta. We also tested eight additional taxa for cross-amplification. The average number of alleles per locus per species was 4.3 and 6.0, respectively. The number of loci that amplified and were variable within the eight related taxa ranged from six to 17. • Conclusions: These markers will be useful in studying mating system evolution, the genetic structure of species’ ranges, hybridization, and the provenance of material used for habitat restoration in C. cheiranthifolia, C. bistorta, and related species. PMID:25309839

  6. Burden of Keloid Disease: A Cross-sectional Health-related Quality of Life Assessment.

    PubMed

    Bijlard, Eveline; Kouwenberg, Casimir A E; Timman, Reinier; Hovius, Steven E R; Busschbach, Jan J V; Mureau, Marc A M

    2017-02-08

    Keloid scars may be painful, itch severely and be cosmetically disturbing. The burden of keloid disease, however, has not yet been determined. This study evaluated the association of keloid disease with health-related quality of life (HRQL) and identified indicators of burden using a cross-sectional survey study, with one disease-specific HRQL measure (Skindex-29) and 2 generic HRQL measures (SF-36 and EQ-5D-5L). A total of 106 keloid patients with no other skin diseases participated in the study. Having keloid disease was associated with a considerable impairment of emotional wellbeing, with most impairment on the emotional and mental HRQL. Pain and itch were the strongest indicators of HRQL impairment in keloid patients. Having painful or itchy keloids was related to low mental and emotional HRQL, implying that patients with keloids require access to effective treatment aimed at alleviating physical symptoms.

  7. Adolescents’ Pregnancy Intentions, Wantedness, and Regret: Cross-Lagged Relations With Mental Health and Harsh Parenting

    PubMed Central

    East, Patricia L.; Chien, Nina C.; Barber, Jennifer S.

    2011-01-01

    The authors used cross-lagged analyses to examine the across-time influences on and consequences of adolescents’ pregnancy intentions, wantedness, and regret. One hundred pregnant Latina adolescents were studied during pregnancy and at 6 and 12 months postpartum. The results revealed 4 main findings: (a) similar to what has been found in adult women, adolescents’ lower prenatal pregnancy intendedness and wantedness predicted initial difficulties in parenting; (b) frequent depression symptoms predicted subsequent lower pregnancy intendedness and wantedness; (c) adolescents’ poor mental health and harsh parenting of their child predicted subsequent higher childbearing regret, and (d) high childbearing regret and parenting stress were reciprocally related across time. In addition, adolescents’ wantedness of their pregnancy declined prenatally to postbirth, and strong pregnancy intendedness and wantedness were not concurrently related to adolescents’ poor prenatal mental health. The findings reveal how adolescents’ thoughts and feelings about their pregnancies are influenced by and predictive of their mental health and parenting experiences. PMID:22544975

  8. A 3D, cross-scale, baroclinic model with implicit vertical transport for the Upper Chesapeake Bay and its tributaries

    NASA Astrophysics Data System (ADS)

    Ye, Fei; Zhang, Yinglong J.; Friedrichs, Marjorie A. M.; Wang, Harry V.; Irby, Isaac D.; Shen, Jian; Wang, Zhengui

    2016-11-01

    We develop a new vertically implicit transport solver, based on two total variation diminishing (TVD) limiters in space and time, inside a 3D unstructured-grid model (SCHISM), and apply it to the Upper Chesapeake Bay (UCB), which has complex geometry and sharp pycnocline. We show that the model is able to accurately and efficiently capture the elevation, velocity, salinity and temperature in both the deep and shallow regions of UCB. Compared with all available CTD casts, the overall model skills have the mean absolute error of 1.08 PSU and 0.85 °C, and correlation coefficient of 0.97 and 0.99 for salinity and temperature respectively. More importantly, the new implicit solver better captures the density stratification, which has great implications on biogeochemistry in this estuarine system. The cross-scale capability of the model is demonstrated by extending the high-resolution grids into a tributary (Chester River) and its sub-tributary (Corsica River), with minimal impact on the model efficiency. The model is also able to capture complex 3D structures at the transition zone between the main bay and the tributary, including the three-layered circulation in Baltimore Harbor. As more and more attention is being paid to the productive shallows in the Chesapeake Bay and other estuaries, the model can serve as a very powerful management tool to understand the impact of both local and remote forcing functions.

  9. Cross-Linkable Hole-Transport Materials Improve the Device Performance of Perovskite Light-Emitting Diodes.

    PubMed

    Huang, Chiung-Fu; Keshtov, Mukhamed L; Chen, Fang-Chung

    2016-10-12

    Hybrid organic/inorganic perovskites are promising candidate materials for use in photovoltaic applications. More recently, they have also become highly attractive as active materials for other optoelectronic devices, including lasers, light-emitting diodes, and photodetectors. Nevertheless, difficulties in forming continuous and uniform films and the existence of a charge-injection barrier between the perovskite layer and the electrodes have hindered the development of high-performance perovskite light-emitting diodes (PeLEDs). In this study, a cross-linked hole-transport layer (HTL) is introduced to improve the hole-injection efficiency of PeLEDs. Furthermore, this layer simultaneously facilitates the formation of smooth perovskite layers, presumably because of the different surface energies. More interestingly, the HTL also exhibits strong solvent effects on the device performance. When the processing solvent for fabricating the HTLs is changed from chlorobenzene to N,N-dimethylformamide (DMF), the perovskite layer becomes more uniform and continuous, leading to better surface coverage and higher device efficiency, presumably because DMF has strong affinity toward the perovskite precursors. The approach presented herein could become a general method for decreasing the hole-injection barrier of PeLEDs and, eventually, lead to higher device performance.

  10. The role of the density gradient on intermittent cross-field transport events in a simple magnetized toroidal plasma

    SciTech Connect

    Theiler, C.; Diallo, A.; Fasoli, A.; Furno, I.; Labit, B.; Ricci, P.; Podesta, M.; Poli, F. M.

    2008-04-15

    Intermittent cross-field particle transport events (ITEs) are studied in the basic toroidal device TORPEX [TORoidal Plasma EXperiment, A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], with focus on the role of the density gradient. ITEs are due to the intermittent radial elongation of an interchange mode. The elongating positive wave crests can break apart and form blobs. This is not necessary, however, for plasma particles to be convected a considerable distance across the magnetic field lines. Conditionally sampled data reveal two different scenarios leading to ITEs. In the first case, the interchange mode grows radially from a slab-like density profile and leads to the ITE. A novel analysis technique reveals a monotonic dependence between the vertically averaged inverse radial density scale length and the probability for a subsequent ITE. In the second case, the mode is already observed before the start of the ITE. It does not elongate radially in a first stage, but at a later time. It is shown that this elongation is preceded by a steepening of the density profile as well.

  11. Cross talk between tetanus neurotoxin-insensitive vesicle-associated membrane protein-mediated transport and L1-mediated adhesion.

    PubMed

    Alberts, Philipp; Rudge, Rachel; Hinners, Ina; Muzerelle, Aude; Martinez-Arca, Sonia; Irinopoulou, Theano; Marthiens, Veronique; Tooze, Sharon; Rathjen, Fritz; Gaspar, Patricia; Galli, Thierry

    2003-10-01

    The membrane-trafficking pathway mediated by tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) in neurons is still unknown. We show herein that TI-VAMP expression is necessary for neurite outgrowth in PC12 cells and hippocampal neurons in culture. TI-VAMP interacts with plasma membrane and endosomal target soluble N-ethylmaleimide-sensitive factor attachment protein receptors, suggesting that TI-VAMP mediates a recycling pathway. L1, a cell-cell adhesion molecule involved in axonal outgrowth, colocalized with TI-VAMP in the developing brain, neurons in culture, and PC12 cells. Plasma membrane L1 was internalized into the TI-VAMP-containing compartment. Silencing of TI-VAMP resulted in reduced expression of L1 at the plasma membrane. Finally, using the extracellular domain of L1 and N-cadherin immobilized on beads, we found that the silencing of TI-VAMP led to impaired L1- but not N-cadherin-mediated adhesion. Furthermore, TI-VAMP- but not synaptobrevin 2-containing vesicles accumulated at the site of the L1 bead-cell junction. We conclude that TI-VAMP mediates the intracellular transport of L1 and that L1-mediated adhesion controls this membrane trafficking, thereby suggesting an important cross talk between membrane trafficking and cell-cell adhesion.

  12. All-optical production and transport of a large 6Li quantum gas in a crossed optical dipole trap

    NASA Astrophysics Data System (ADS)

    Gross, Ch.; Gan, H. C. J.; Dieckmann, K.

    2016-05-01

    We report on an efficient production scheme for a large quantum degenerate sample of fermionic lithium. The approach is based on our previous work on narrow-line 2 S1 /2→3 P3 /2 laser cooling resulting in a high phase-space density of up to 3 ×10-4 . This allows utilizing a large-volume crossed optical dipole trap with a total power of 45 W , leading to high loading efficiency and 8 ×106 trapped atoms. The same optical trapping configuration is used for rapid adiabatic transport over a distance of 25 cm in 0.9 s , and subsequent evaporative cooling. With optimized evaporation we achieve a degenerate Fermi gas with 1.7 ×106 atoms at a temperature of 60 nK , corresponding to T /TF=0.16 (2 ) . Furthermore, the performance is demonstrated by evaporation near a broad Feshbach resonance creating a molecular Bose-Einstein condensate of 3 ×105 lithium dimers.

  13. Mesoscale eddies drive cross-shelf transport, particle and nutrient biogeochemistry, and the nutritional value of zooplankton

    NASA Astrophysics Data System (ADS)

    Waite, A.

    2016-02-01

    Mesoscale eddies drive a significant component of cross-shelf transport important in the ecology of coastal ecosystems. The Leeuwin Current off Western Australia has a high kinetic energy in southwest WA which peaks and becomes unstable in the austral autumn triggering the formation of eddies. We captured the dynamics of an evolving anticyclonic eddy in situ and we traced water masses as they were incorporated into the eddy. ADCP profiles confirmed periodic offshore movement of 2 Sv of shelf waters into the forming eddy from the adjacent shelf, carrying a load of shelf-sourced organic particles. Oxygen and nutrient profiles suggested rapid remineralization of nitrate mid-depth in the isolated water mass as it rotated, with a total drawdown of oxygen of 3.6 mol m-2 to 350 m ( 0.5 mol O2 m-2 d-1) on the timescale of 1 week. This implies that nitrate is acting primarily as a regenerated nutrient rather than as a source of new nitrogen. Zooplankton isotopic signatures indicated that warm-core eddies carried animals of poorer nutritional value than cold-core eddies, and this was reflected in the lipid content of rock lobster larvae isolated in the two eddy types. We present a conceptual model of the potential bottom-up control of zooplankton lipid stores by the mesoscale eddy field.

  14. Can innovative ambulance transport avert pregnancy–related deaths? One–year operational assessment in Ethiopia

    PubMed Central

    Godefay, Hagos; Kinsman, John; Admasu, Kesetebirhan; Byass, Peter

    2016-01-01

    Background To maximise the potential benefits of maternity care services, pregnant women need to be able to physically get to health facilities in a timely manner. In most of sub–Saharan Africa, transport represents a major practical barrier. Here we evaluate the extent to which an innovative national ambulance service in Ethiopia, together with mobile phones, may have been successful in averting pregnancy–related deaths. Methods An operational assessment of pregnancy–related deaths in relation to utilisation of the new national ambulance service was undertaken in six randomly selected Districts in northern Ethiopia. All 183 286 households in the six randomly selected Districts were visited to identify live–births and deaths among women of reproductive age that occurred over a one–year period. The uptake of the new ambulance transport service for women’s deliveries in the same six randomly selected Districts over the same period was determined retrospectively from ambulance log books. Pregnancy–related deaths as determined by the World Health Organization (WHO 2012) verbal autopsy tool [13] and the InterVA–4 model [14] were analysed against ambulance utilisation by District, month, local area, distance from health facility and mobile network coverage. Findings A total of 51 pregnancy–related deaths and 19 179 live–births were documented. Pregnancy–related mortality for Districts with above average ambulance utilisation was 149 per 100 000 live–births (95% confidence interval CI 77–260), compared with 350 per 100 000 (95% CI 249–479) for below average utilisation (P = 0.01). Distance to a health facility, mobile network availability and ambulance utilisation were all significantly associated with pregnancy–related mortality on a bivariable basis. On a multivariable basis, ambulance non–utilisation uniquely persisted as a significant determinant of mortality (mortality rate ratio 1.97, 95% CI 1.05–3.69; P = 0

  15. Can innovative ambulance transport avert pregnancy-related deaths? One-year operational assessment in Ethiopia.

    PubMed

    Godefay, Hagos; Kinsman, John; Admasu, Kesetebirhan; Byass, Peter

    2016-06-01

    To maximise the potential benefits of maternity care services, pregnant women need to be able to physically get to health facilities in a timely manner. In most of sub-Saharan Africa, transport represents a major practical barrier. Here we evaluate the extent to which an innovative national ambulance service in Ethiopia, together with mobile phones, may have been successful in averting pregnancy-related deaths. An operational assessment of pregnancy-related deaths in relation to utilisation of the new national ambulance service was undertaken in six randomly selected Districts in northern Ethiopia. All 183 286 households in the six randomly selected Districts were visited to identify live-births and deaths among women of reproductive age that occurred over a one-year period. The uptake of the new ambulance transport service for women's deliveries in the same six randomly selected Districts over the same period was determined retrospectively from ambulance log books. Pregnancy-related deaths as determined by the World Health Organization (WHO 2012) verbal autopsy tool [13] and the InterVA-4 model [14] were analysed against ambulance utilisation by District, month, local area, distance from health facility and mobile network coverage. A total of 51 pregnancy-related deaths and 19 179 live-births were documented. Pregnancy-related mortality for Districts with above average ambulance utilisation was 149 per 100 000 live-births (95% confidence interval CI 77-260), compared with 350 per 100 000 (95% CI 249-479) for below average utilisation (P = 0.01). Distance to a health facility, mobile network availability and ambulance utilisation were all significantly associated with pregnancy-related mortality on a bivariable basis. On a multivariable basis, ambulance non-utilisation uniquely persisted as a significant determinant of mortality (mortality rate ratio 1.97, 95% CI 1.05-3.69; P = 0.03). The uptake of freely available transport in connection with women

  16. Diffusion related isotopic fractionation effects with one-dimensional advective-dispersive transport.

    PubMed

    Xu, Bruce S; Lollar, Barbara Sherwood; Passeport, Elodie; Sleep, Brent E

    2016-04-15

    Aqueous phase diffusion-related isotope fractionation (DRIF) for carbon isotopes was investigated for common groundwater contaminants in systems in which transport could be considered to be one-dimensional. This paper focuses not only on theoretically observable DRIF effects in these systems but introduces the important concept of constraining "observable" DRIF based on constraints imposed by the scale of measurements in the field, and on standard limits of detection and analytical uncertainty. Specifically, constraints for the detection of DRIF were determined in terms of the diffusive fractionation factor, the initial concentration of contaminants (C0), the method detection limit (MDL) for isotopic analysis, the transport time, and the ratio of the longitudinal mechanical dispersion coefficient to effective molecular diffusion coefficient (Dmech/Deff). The results allow a determination of field conditions under which DRIF may be an important factor in the use of stable carbon isotope measurements for evaluation of contaminant transport and transformation for one-dimensional advective-dispersive transport. This study demonstrates that for diffusion-dominated transport of BTEX, MTBE, and chlorinated ethenes, DRIF effects are only detectable for the smaller molar mass compounds such as vinyl chloride for C0/MDL ratios of 50 or higher. Much larger C0/MDL ratios, corresponding to higher source concentrations or lower detection limits, are necessary for DRIF to be detectable for the higher molar mass compounds. The distance over which DRIF is observable for VC is small (less than 1m) for a relatively young diffusive plume (<100years), and DRIF will not easily be detected by using the conventional sampling approach with "typical" well spacing (at least several meters). With contaminant transport by advection, mechanical dispersion, and molecular diffusion this study suggests that in field sites where Dmech/Deff is larger than 10, DRIF effects will likely not be

  17. Regulation of iron transport related genes by boron in the marine bacterium Marinobacter algicola DG893.

    PubMed

    Romano, Ariel; Trimble, Lyndsay; Hobusch, Ashtian R; Schroeder, Kristine J; Amin, Shady A; Hartnett, Andrej D; Barker, Ryan A; Crumbliss, Alvin L; Carrano, Carl J

    2013-08-01

    While there has been extensive interest in the use of boron isotope ratios as a surrogate of pH in paleoclimate studies in the context of climate change-related questions, the high (0.4 mM) concentration and the depth-independent (conservative or non-nutrient-like) concentration profile of this element have led to boron being neglected as a potentially biologically relevant element in the modern ocean. Here we report that boron affects the expression of a number of protein and genes in the "algal-associated" Gram-negative marine bacterium Marinobacter algicola DG893. Most intriguingly, a number of these proteins and genes are related to iron uptake. In a recent separate publication we have shown that boron regulates one such iron transport related protein, i.e. the periplasmic iron binding protein FbpA via a direct interaction of the metalloid with this protein. Here we show that a number of other iron uptake related genes are also affected by boron but in the opposite way i.e. they are up-regulated. We propose that the differential effect of boron on FbpA expression relative to other iron transport related genes is a result of an interaction between boron and the global iron regulatory protein Fur.

  18. Blood pressure of urban school children in relation to road-traffic noise, traffic density and presence of public transport.

    PubMed

    Paunovic, Katarina; Belojevic, Goran; Jakovljevic, Branko

    2013-01-01

    The aim of the study was to investigate the relationship between noise levels, traffic density and the presence of public transport and children's blood pressure. Another aim was to assess the applicability of public transport as a proxy indicator of noise exposure. A cross-sectional study involved 1113 children aged 7-11 years from a central municipality in Belgrade. Equivalent noise levels were measured in front of all schools and in the middle of all streets. Traffic density was defined as number of light and heavy vehicles per hour. The number of public transport vehicles was calculated from official timetables. Children's addresses were matched with noise levels and transport maps. A physician measured blood pressure with the sphygmomanometer. Children attending schools with public transport running nearby had by 1.3 mmHg higher systolic pressure than did children from schools without public transport. This relationship was independent from children's age, gender, and body mass index, family history of hypertension, some dwelling characteristics, and lifestyle habits. The association between diastolic pressure and public transport was statistically insignificant. The study indicated a possible positive association between the presence of public transport in the vicinity of schools with systolic blood pressure in 7-11 year-old schoolchildren. The presence of public transport may serve as an auxiliary indicator of noise exposure in undeveloped countries with limited capacities for noise measurement or modeling.

  19. A possible closure relation for heat transport in the solar wind

    NASA Technical Reports Server (NTRS)

    Feldman, W. C.; Asbridge, J. R.; Bame, S. J.; Gosling, J. T.; Lemons, D. S.

    1979-01-01

    The objective of the present paper is to search for an empirical closure relation for solar wind heat transport that applies to a microscopic scale. This task is approached by using the quasi-linear wave-particle formalism proposed by Perkins (1973) as a guide to derive an equation relating the relative drift speed between core-electron and proton populations to local bulk flow conditions. The resulting relationship, containing one free parameter, is found to provide a good characterization of Los Alamos Imp electron data measuring during the period from March 1971 through August 1974. An empirical closure relation is implied by this result because of the observed proportionality between heat flux and relative drift speed.

  20. Drug use, mental health and problems related to crime and violence: cross-sectional study1

    PubMed Central

    Claro, Heloísa Garcia; de Oliveira, Márcia Aparecida Ferreira; Bourdreaux, Janet Titus; Fernandes, Ivan Filipe de Almeida Lopes; Pinho, Paula Hayasi; Tarifa, Rosana Ribeiro

    2015-01-01

    Objective: to investigate the correlation between disorders related to the use of alcohol and other drugs and symptoms of mental disorders, problems related to crime and violence and to age and gender. Methods: cross-sectional descriptive study carried out with 128 users of a Psychosocial Care Center for Alcohol and other Drugs, in the city of São Paulo, interviewed by means of the instrument entitled Global Appraisal of Individual Needs - Short Screener. Univariate and multiple linear regression models were used to verify the correlation between the variables. Results: using univariate regression models, internalizing and externalizing symptoms and problems related to crime/violence proved significant and were included in the multiple model, in which only the internalizing symptoms and problems related to crime and violence remained significant. Conclusions: there is a correlation between the severity of problems related to alcohol use and severity of mental health symptoms and crime and violence in the study sample. The results emphasize the need for an interdisciplinary and intersectional character of attention to users of alcohol and other drugs, since they live in a socially vulnerable environment. PMID:26626010

  1. Retirement planning and work-related variables in Chinese older nurses: A cross-sectional study.

    PubMed

    Liu, Peng-Cheng; Zhang, Huan-Huan; Zhang, Mei-Ling; Ying, Jie; Shi, Ying; Wang, Shou-Qi; Sun, Jiao

    2017-08-29

    To explore the situation of older nurses approaching retirement with regard to their retirement planning, and the relationship of their retirement planning behaviour with the job environment and job satisfaction under their current employment arrangements and other work-related variables. Nurse shortage has become a global phenomenon that can be alleviated by retaining older nurses in service. The Chinese government proposed the "Incremental Delay Retirement Age Policy." However, older nurses face delayed retirement but lack retirement plans. A cross-sectional questionnaire survey was conducted among a convenience sample of older retiring nurses (n = 152; 84.92% response rate) recruited from every department of four large general hospitals in Changchun, Jilin Province from June to August 2016. The majority of the respondents presented poor retirement planning (n = 122, 80.3%). The independent variables of information exchange with patients, teamwork and personal growth and development explained approximately 16.6% of the variance in retirement planning. Nurse-patient communication and personal growth and development can promote retirement planning, but teamwork is negatively related to retirement planning. Retirement planning by Chinese older nurses is related to certain work-related variables. However, many other work-related variables were not associated with retirement planning and require further research. Overall, Chinese older retiring nurses must improve their retirement planning practices. © 2017 John Wiley & Sons Ltd.

  2. Cross-language activation of morphological relatives in cognates: the role of orthographic overlap and task-related processing

    PubMed Central

    Mulder, Kimberley; Dijkstra, Ton; Baayen, R. Harald

    2015-01-01

    We considered the role of orthography and task-related processing mechanisms in the activation of morphologically related complex words during bilingual word processing. So far, it has only been shown that such morphologically related words (i.e., morphological family members) are activated through the semantic and morphological overlap they share with the target word. In this study, we investigated family size effects in Dutch-English identical cognates (e.g., tent in both languages), non-identical cognates (e.g., pil and pill, in English and Dutch, respectively), and non-cognates (e.g., chicken in English). Because of their cross-linguistic overlap in orthography, reading a cognate can result in activation of family members both languages. Cognates are therefore well-suited for studying mechanisms underlying bilingual activation of morphologically complex words. We investigated family size effects in an English lexical decision task and a Dutch-English language decision task, both performed by Dutch-English bilinguals. English lexical decision showed a facilitatory effect of English and Dutch family size on the processing of English-Dutch cognates relative to English non-cognates. These family size effects were not dependent on cognate type. In contrast, for language decision, in which a bilingual context is created, Dutch and English family size effects were inhibitory. Here, the combined family size of both languages turned out to better predict reaction time than the separate family size in Dutch or English. Moreover, the combined family size interacted with cognate type: the response to identical cognates was slowed by morphological family members in both languages. We conclude that (1) family size effects are sensitive to the task performed on the lexical items, and (2) depend on both semantic and formal aspects of bilingual word processing. We discuss various mechanisms that can explain the observed family size effects in a spreading activation framework

  3. Molecular cloning of mouse amino acid transport system B0, a neutral amino acid transporter related to Hartnup disorder.

    PubMed

    Bröer, Angelika; Klingel, Karin; Kowalczuk, Sonja; Rasko, John E J; Cavanaugh, Juleen; Bröer, Stefan

    2004-06-04

    Resorption of amino acids in kidney and intestine is mediated by transporters, which prefer groups of amino acids with similar physico-chemical properties. It is generally assumed that most neutral amino acids are transported across the apical membrane of epithelial cells by system B(0). Here we have characterized a novel member of the Na(+)-dependent neurotransmitter transporter family (B(0)AT1) isolated from mouse kidney, which shows all properties of system B(0). Flux experiments showed that the transporter is Na(+)-dependent, electrogenic, and actively transports most neutral amino acids but not anionic or cationic amino acids. Superfusion of mB(0)AT1-expressing oocytes with neutral amino acids generated inward currents, which were proportional to the fluxes observed with labeled amino acids. In situ hybridization showed strong expression in intestinal microvilli and in the proximal tubule of the kidney. Expression of mouse B(0)AT1 was restricted to kidney, intestine, and skin. It is generally assumed that mutations of the system B(0) transporter underlie autosomal recessive Hartnup disorder. In support of this notion mB(0)AT1 is located on mouse chromosome 13 in a region syntenic to human chromosome 5p15, the locus of Hartnup disorder. Thus, the human homologue of this transporter is an excellent functional and positional candidate for Hartnup disorder.

  4. Conformational Motions and Functionally Key Residues for Vitamin B12 Transporter BtuCD-BtuF Revealed by Elastic Network Model with a Function-Related Internal Coordinate.

    PubMed

    Su, Ji-Guo; Zhang, Xiao; Zhao, Shu-Xin; Li, Xing-Yuan; Hou, Yan-Xue; Wu, Yi-Dong; Zhu, Jian-Zhuo; An, Hai-Long

    2015-08-04

    BtuCD-BtuF from Escherichia coli is a binding protein-dependent adenosine triphosphate (ATP)-binding cassette (ABC) transporter system that uses the energy of ATP hydrolysis to transmit vitamin B12 across cellular membranes. Experimental studies have showed that during the transport cycle, the transporter undergoes conformational transitions between the "inward-facing" and "outward-facing" states, which results in the open-closed motions of the cytoplasmic gate of the transport channel. The opening-closing of the channel gate play critical roles for the function of the transporter, which enables the substrate vitamin B12 to be translocated into the cell. In the present work, the extent of opening of the cytoplasmic gate was chosen as a function-related internal coordinate. Then the mean-square fluctuation of the internal coordinate, as well as the cross-correlation between the displacement of the internal coordinate and the movement of each residue in the protein, were calculated based on the normal mode analysis of the elastic network model to analyze the function-related motions encoded in the structure of the system. In addition, the key residues important for the functional motions of the transporter were predicted by using a perturbation method. In order to facilitate the calculations, the internal coordinate was introduced as one of the axes of the coordinate space and the conventional Cartesian coordinate space was transformed into the internal/Cartesian space with linear approximation. All the calculations were carried out in this internal/Cartesian space. Our method can successfully identify the functional motions and key residues for the transporter BtuCD-BtuF, which are well consistent with the experimental observations.

  5. Military-related sexual assault in Canada: a cross-sectional survey

    PubMed Central

    Watkins, Kimberley; Bennett, Rachel; Zamorski, Mark A.; Richer, Isabelle

    2017-01-01

    Background: Most research on military-related sexual assault is based on the United States military and has important limitations, such as low response rates. We sought to estimate the lifetime prevalence of sexual assault, assess its relation to military service and identify the circumstances, correlates and associations with mental disorders of military-related sexual assault among Canadian military personnel. Methods: We used the 2013 Canadian Forces Mental Health Survey, a cross-sectional representative survey of Canadian Regular Force personnel (n = 6696). The sample was weighted to be representative of the entire Canadian Armed Forces Regular Force population in 2012 (n = 67 776), as per Statistics Canada requirements. We assessed lifetime trauma exposure and past-year mental disorders using the Composite International Diagnostic Interview. We defined lifetime military-related sexual assault as forced sexual activity or unwanted sexual touching that occurred on deployment or in another military workplace, or was perpetrated by Department of National Defence or Canadian Armed Forces personnel. We defined all other sexual assault as non-military-related sexual assault. Results: Self-reported sexual assault was more prevalent among women (non-military-related sexual assault 24.2%, military-related sexual assault 15.5%) than men (5.9% and 0.8%, respectively). About a quarter of women with military-related sexual assault reported experiencing at least 1 event on deployment. After covariates were controlled for, military-related sexual assault was independently associated with any lifetime and any past-year mental disorder (adjusted odds ratio 2.9 and 3.0, respectively) and lifetime and past-year posttraumatic stress disorder (adjusted odds ratio 4.3 and 4.1, respectively). Interpretation: Canadian military women are at increased risk for sexual assault and military-related sexual assault relative to their male counterparts. Deployment may be a period of elevated

  6. Cumulative Relative Reactivity: A Concept for Modeling Aquifer-Scale Reactive Transport

    NASA Astrophysics Data System (ADS)

    Loschko, M.; Cirpka, O. A.; Wöhling, T.; Rudolph, D. L.

    2016-12-01

    Quantitative understanding of pollutant fluxes from diffuse input and turnover of pollutants at catchment scale requires process-based numerical models that can explain observed time series of heads, fluxes, and concentrations. To deal with the high level of uncertainty a probabilistic framework is necessary. Due to the high computational effort, such evaluations cannot be done with a spatially explicit reactive-transport model. Conceptual simplifications are needed. The proposed approach is based on travel times and relative reactivity. The latter quantifies the intensity of the chemical reaction relative to a reference reaction rate and can be interpreted as the strength of electron-donor (or electron-acceptor) released by the matrix. In general, the relative reactivity is a spatially variable property reflecting the geology of the formation. In this approach, the paths of individual water parcels are tracked through the aquifer, the age of the water parcels is evaluated, and the relative reactivity is integrated along their trajectories. By switching from space-time discretization to cumulative relative reactivity, advective-reactive transport can be simulated by solving a single system of ordinary differential equations for each combination of concentrations in the inflow. In comparison to solving the advection-dispersion-reaction equation in a spatially explicit way, solving a limited number of ordinary differential equations is computationally significantly less costly. This permits the application of Monte-Carlo methods within a stochastic framework. The validity of the approach was tested in a two-dimensional test case, where the errors introduced by neglecting dispersive mixing were analyzed. The applicability of the approach is demonstrated in a synthetic case study of aerobic respiration and denitrification in the saturated zone using a three-dimensional steady-state groundwater flow model combined with the simplified reactive transport approach.

  7. Valuation of social and health effects of transport-related air pollution in Madrid (Spain).

    PubMed

    Monzón, Andrés; Guerrero, María-José

    2004-12-01

    Social impacts of pollutants from mobile sources are a key element in urban design and traffic planning. One of the most relevant impacts is health effects associated with high pollution periods. Madrid is a city that suffers chronic congestion levels and some periods of very stable atmospheric conditions; as a result, pollution levels exceed air quality standards for certain pollutants. This paper focuses on the social evaluation of transport-related emissions. A new methodology to evaluate those impacts in monetary terms has been designed and applied to Madrid. The method takes into account costs associated with losses in working time, mortality and human suffering; calculated using an impact pathway approach linked to CORINAIR emissions. This also allows the calculation of social costs associated with greenhouse gas impacts. As costs have been calculated individually by effect and mode of transport, they can be used to design pricing policies based on real social costs. This paper concludes that the health and social costs of transport-related air pollution in Madrid is 357 Meuro. In these circumstances, the recent public health tax applied in Madrid is clearly correct and sensible with a fair pricing policy on car use.

  8. Uncertainties related to the representation of momentum transport in shallow convection

    NASA Astrophysics Data System (ADS)

    Schlemmer, Linda; Bechtold, Peter; Sandu, Irina; Ahlgrimm, Maike

    2017-04-01

    The vertical transport of horizontal momentum by convection has an important impact on the general circulation of the atmosphere as well as on the life cycle and track of cyclones. So far convective momentum transport (CMT) has mostly been studied for deep convection, whereas little is known about its characteristics and importance in shallow convection. In this study CMT by shallow convection is investigated by analyzing both data from large-eddy simulations (LES) and simulations performed with the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). In addition, the central terms underlying the bulk mass-flux parametrization of CMT are evaluated offline. Further, the uncertainties related to the representation of CMT are explored by running the stochastically perturbed parametrizations (SPP) approach of the IFS. The analyzed cases exhibit shallow convective clouds developing within considerable low-level wind shear. Analysis of the momentum fluxes in the LES data reveals significant momentum transport by the convection in both cases, which is directed down-gradient despite substantial organization of the cloud field. A detailed inspection of the convection parametrization reveals a very good representation of the entrainment and detrainment rates and an appropriate representation of the convective mass and momentum fluxes. To determine the correct values of mass-flux and in-cloud momentum at the cloud base in the parametrization yet remains challenging. The spread in convection-related quantities generated by the SPP is reasonable and addresses many of the identified uncertainties.

  9. Measurements of condensation nuclei above the jet stream - Evidence for cross jet transport by waves and new particle formation at high altitudes

    NASA Technical Reports Server (NTRS)

    Wilson, J. C.; Lai, W. T.; Smith, S. D.

    1991-01-01

    Condensation nuclei were used as a tracer in midlatitude NASA Stratosphere-Troposphere Exchange Project (STEP) experiments in April and May 1984 in order to study transport in the stratosphere. The very large scale, mean CN distribution was distorted by waves which had the effect of transporting air with anticyclonic properties several degrees to the cyclonic side of the jet and created a strongly layered structure in the CN distribution. Unfiltered CN data revealed short-wavelength oscillations in the CN distribution at the interface between the transported anticyclonic air parcel and the adjacent cyclonic air mass. These oscillations were also seen in the ozone data and increase the potential for mixing along that interface. If the mixing does occur, a wave mechanism for cross-jet transport has been observed.

  10. Measurements of condensation nuclei above the jet stream - Evidence for cross jet transport by waves and new particle formation at high altitudes

    NASA Technical Reports Server (NTRS)

    Wilson, J. C.; Lai, W. T.; Smith, S. D.

    1991-01-01

    Condensation nuclei were used as a tracer in midlatitude NASA Stratosphere-Troposphere Exchange Project (STEP) experiments in April and May 1984 in order to study transport in the stratosphere. The very large scale, mean CN distribution was distorted by waves which had the effect of transporting air with anticyclonic properties several degrees to the cyclonic side of the jet and created a strongly layered structure in the CN distribution. Unfiltered CN data revealed short-wavelength oscillations in the CN distribution at the interface between the transported anticyclonic air parcel and the adjacent cyclonic air mass. These oscillations were also seen in the ozone data and increase the potential for mixing along that interface. If the mixing does occur, a wave mechanism for cross-jet transport has been observed.

  11. Cross-structural priming: prepositional phrase attachment primes relative clause attachment.

    PubMed

    Loncke, Maaike; Van Laere, Sébastien M J; Desmet, Timothy

    2011-01-01

    In this paper we show that attachment height (high vs. low attachment) of a modifier to a complex noun phrase (CNP; e.g., "the servant of the actress"), can be primed between dissimilar syntactic structures. In a sentence completion experiment, we found that the attachment height of a prepositional phrase (PP) in the prime sentence primed the attachment height of a relative clause (RC) in the target sentence. This cross-structural priming effect cannot be explained in terms of the priming of specific phrase-structure rules or even sequences of specific phrase-structure rules (Scheepers, 2003), because the attachment of a PP to a CNP is generated by a different phrase-structure rule than the attachment of an RC. However, the present data suggest that the location at which the RC is attached to the CNP is mentally represented, independent of the specific phrase-structure rule that is attached, or by extension, that the abstract hierarchical configuration of the full CNP and the attached RC is represented (Desmet & Declercq, 2006). This is the first demonstration of a cross-structural priming effect that cannot be captured by phrase-structure rules.

  12. Review of cross-cultural issues related to quality of life after spinal cord injury.

    PubMed

    Tate, Denise; Forchheimer, Martin

    2014-01-01

    Quality of life (QOL) is a dynamic concept that means different things to different people, both in the general public and within the research community. Because of this, a common definition of QOL has been hard to achieve. This article reviews cross-cultural issues related to QOL research in spinal cord injury (SCI). Many factors influence QOL for persons with SCI, including observable and objective indicators and subjective self-report ones. The World Health Organization's International Classification of Function, Disability and Health is used in this article as a framework to better understand how these factors may influence QOL. A number of important steps are summarized with respect to measurement issues in QOL. A comparison between data from 2 countries (United States and Brazil) using the International SCI QOL Basic Data Set shows similarities in scores and good reliability in the Brazilian sample. Substantial, significant correlations were observed among the SCI QOL Basic Data Set items and the WHOQOL-BREF within the US sample. The article ends with a set of recommendations for the development of cross-cultural measures of QOL for use in the SCI population.

  13. An Event-Related Potential Study of Cross-modal Morphological and Phonological Priming.

    PubMed

    Justus, Timothy; Yang, Jennifer; Larsen, Jary; de Mornay Davies, Paul; Swick, Diane

    2009-11-01

    The current work investigated whether differences in phonological overlap between the past- and present-tense forms of regular and irregular verbs can account for the graded neurophysiological effects of verb regularity observed in past-tense priming designs. Event-related potentials were recorded from sixteen healthy participants who performed a lexical-decision task in which past-tense primes immediately preceded present-tense targets. To minimize intra-modal phonological priming effects, cross-modal presentation between auditory primes and visual targets was employed, and results were compared to a companion intra-modal auditory study (Justus, Larsen, de Mornay Davies, & Swick, 2008). For both regular and irregular verbs, faster response times and reduced N400 components were observed for present-tense forms when primed by the corresponding past-tense forms. Although behavioral facilitation was observed with a pseudopast phonological control condition, neither this condition nor an orthographic-phonological control produced significant N400 priming effects. Instead, these two types of priming were associated with a post-lexical anterior negativity (PLAN). Results are discussed with regard to dual- and single-system theories of inflectional morphology, as well as intra- and cross-modal prelexical priming.

  14. An Event-Related Potential Study of Cross-modal Morphological and Phonological Priming

    PubMed Central

    Justus, Timothy; Yang, Jennifer; Larsen, Jary; de Mornay Davies, Paul; Swick, Diane

    2009-01-01

    The current work investigated whether differences in phonological overlap between the past- and present-tense forms of regular and irregular verbs can account for the graded neurophysiological effects of verb regularity observed in past-tense priming designs. Event-related potentials were recorded from sixteen healthy participants who performed a lexical-decision task in which past-tense primes immediately preceded present-tense targets. To minimize intra-modal phonological priming effects, cross-modal presentation between auditory primes and visual targets was employed, and results were compared to a companion intra-modal auditory study (Justus, Larsen, de Mornay Davies, & Swick, 2008). For both regular and irregular verbs, faster response times and reduced N400 components were observed for present-tense forms when primed by the corresponding past-tense forms. Although behavioral facilitation was observed with a pseudopast phonological control condition, neither this condition nor an orthographic-phonological control produced significant N400 priming effects. Instead, these two types of priming were associated with a post-lexical anterior negativity (PLAN). Results are discussed with regard to dual- and single-system theories of inflectional morphology, as well as intra- and cross-modal prelexical priming. PMID:20160930

  15. Review of Cross-Cultural Issues Related to Quality of Life After Spinal Cord Injury

    PubMed Central

    Tate, Denise

    2014-01-01

    Quality of life (QOL) is a dynamic concept that means different things to different people, both in the general public and within the research community. Because of this, a common definition of QOL has been hard to achieve. This article reviews cross-cultural issues related to QOL research in spinal cord injury (SCI). Many factors influence QOL for persons with SCI, including observable and objective indicators and subjective self-report ones. The World Health Organization’s International Classification of Function, Disability and Health is used in this article as a framework to better understand how these factors may influence QOL. A number of important steps are summarized with respect to measurement issues in QOL. A comparison between data from 2 countries (United States and Brazil) using the International SCI QOL Basic Data Set shows similarities in scores and good reliability in the Brazilian sample. Substantial, significant correlations were observed among the SCI QOL Basic Data Set items and the WHOQOL-BREF within the US sample. The article ends with a set of recommendations for the development of cross-cultural measures of QOL for use in the SCI population. PMID:25484564

  16. Cross-lagged relations among parenting, children's emotion regulation, and psychosocial adjustment in early adolescence.

    PubMed

    Otterpohl, Nantje; Wild, Elke

    2015-01-01

    Numerous studies have reported substantive correlations between indicators of parenting, children's emotion regulation (ER), and children's psychosocial adjustment. However, studies on underlying mechanisms are scarce. Particularly in early adolescence, it is still unclear whether relations between parenting and ER are caused by adolescent behavior, by parent behavior, or by reciprocal processes. Moreover, it is unclear whether ER can be seen as an antecedent or a consequence of psychosocial adjustment. The aim of this study was to examine predictive relations among parenting and adolescents' ER, and adolescents' ER and psychosocial adjustment, respectively. We collected longitudinal, multiple informant data at two measurement occasions (Grade 6, Grade 7). All told, 1,100 adolescents (10-14 years) and their parents filled out questionnaires assessing responsiveness and psychological control, adolescents' anger regulation, and adolescents' problem and prosocial behavior. Cross-lagged analyses revealed reciprocal effects between parenting, ER, and adjustment for the parent and boys', but not for the girls', report. Moreover, relations were different for adolescents with versus without clinically elevated symptoms of psychopathology. Our findings support the assumption that reciprocal relations between parenting, ER, and psychosocial adjustment are likely to persist until early adolescence. Nevertheless, the moderating role of gender and psychopathology should be taken into account. Possible reasons for the different findings, and practical implications, are discussed.

  17. A cross-sectional study of chronic wound-related pain and itching.

    PubMed

    Paul, Julia

    2013-07-01

    Persons with chronic wounds may experience wound-related itch (pruritus) and pain. A cross-sectional study was conducted to examine the occurrence of itch and pain in chronic wounds and the relationship of the intensity between these factors. Patients in an outpatient wound care center, 18 years and older with an open wound, were recruited consecutively over a 5-month period. The 199 participants (112 [56%] men) had a mean age of 67 years (range 21-98 years); one wound per person was addressed and included venous (31), arterial (23), neuropathic (31), pressure-related (33), traumatic (37), and "other" (41) wounds. Wound-related pain and itch data were obtained using a modified Paul-Pieper Itching Questionnaire and Characteristics of Itch Questionnaire. Responses were hand-recorded and coded without personal identifiers and analyzed using descriptive statistics, and associations among data were assessed using Pearson chi-square, Mantel-Haenszel chi-square, and Cochran-Armitage trend tests. Wound-related itch was significantly associated with participant age (P = 0.011) and employment status (P = 0.003). Wound-related pain was significantly associated only with education level (P = 0.048). Persons with venous wounds had both the largest proportion with wound-related itch (45.2%) and the largest proportion with wound-related pain (61.2%) out of all of the wound types. Persons with diabetic neuropathy had both the smallest proportion with wound-related itch (16.1%) and the smallest proportion with wound-related pain (35.4%) among all of the wound types. Associations between wound type and wound-related itch or pain were not significant. When venous wounds were compared to all other wound types combined, wound-related itch was significantly associated (P = 0.021) with wound type - ie, venous wound type and itch was statistically significant when venous wounds were compared to a combination of all other wound types. Wound-related pain and itch occurred together in 35

  18. Charge sensing and spin-related transport property of p-channel silicon quantum dots

    NASA Astrophysics Data System (ADS)

    Yamaoka, Yu; Iwasaki, Kazuma; Oda, Shunri; Kodera, Tetsuo

    2017-04-01

    We demonstrate the detection of single hole tunneling through physically defined silicon quantum dots (QDs) by charge sensing. We estimate capacitive couplings between the QDs and tuning gates by simulation based on the Monte Carlo method. In addition, an investigation of spin-related transport is presented. Pauli spin blockade is observed in double QDs, where hole transport is blocked by forbidden transitions between triplet and singlet states. The magnetic field dependence of the leakage current in Pauli spin blockade shows a dip characteristic at zero field, which is explained by spin relaxation due to spin-orbit coupling with phonons. We extract the dip width B C ˜ 65 mT and a spin relaxation rate Γrel ˜ 55 MHz. The small dip width and high spin relaxation rate reflect a strong spin-orbit coupling.

  19. Decadal variation of the North Atlantic meridional heat transport and its relation to atmospheric processes

    NASA Astrophysics Data System (ADS)

    Martin, T.; Ruprecht, E.

    2007-02-01

    The effects of the meridional heat transport in the North Atlantic Ocean (HTR) on the north hemispheric climate are studied using the results of the coupled model ECHAM5/MPI-OM. Significant correlations exist between HTR and atmospheric processes over the Nordic Seas and the Eurasian continent only for low (periods longer than 40 years) and intermediate frequency variations (periods between 25 and 40 years). A positive HTR anomaly at 30°N is highly correlated with turbulent heat fluxes around 50°N. The transport through 70°N is directly related to the fluxes over the Nordic seas. From the correlation pattern with the atmospheric surface temperature and pressure one can conclude that the heat anomalies propagate along the cyclone tracks towards northeast over the Eurasian continent. The HRT anomalies are negatively correlated with the pressure over the Nordic seas and with the winter time anticyclone intensity over Siberia.

  20. Wigner time delay and related concepts: Application to transport in coherent conductors

    NASA Astrophysics Data System (ADS)

    Texier, Christophe

    2016-08-01

    The concepts of Wigner time delay and Wigner-Smith matrix allow us to characterise temporal aspects of a quantum scattering process. The paper reviews the statistical properties of the Wigner time delay for disordered systems; the case of disorder in 1D with a chiral symmetry is discussed and the relation with exponential functionals of the Brownian motion is underlined. Another approach for the analysis of time delay statistics is the random matrix approach, from which we review few results. As a practical illustration, we briefly outline a theory of non-linear transport and AC transport developed by Büttiker and coworkers, where the concept of Wigner-Smith time delay matrix is a central piece allowing us to describe screening properties in out-of-equilibrium coherent conductors.

  1. Stress during simulated emergency transportation in a rescue helicopter: cross-correlation between stress hormones, vital functions and subjective well-being.

    PubMed

    Witzel, K; Elzer, M; Koch, Horst J

    2009-06-01

    Vital functions and stress hormone levels during simulated emergency helicopter transport in healthy volunteers. Twenty-three volunteers were subjected to a simulated 15 minute rescue helicopter transport. We determined vital functions, ACTH, cortisol and prolactin during the flight and filled in a standardized questionnaire before and after the flight. Data were analysed descriptively, by means of cross tabulation, Spearman rank correlation and cross-correlation technique. During take-off we recorded a significant increase of vital parameters such as heart rate. Prolactin concentration rose slightly after the start. Maximum cortisol and ACTH levels were found before take-off and then they decreased gradually. As expected, ACTH and cortisol cross-correlated significantly without any relevant time lag. Test items showed a feeling of fear and concern before take off. After the flight the volunteers reported having less stress than expected. Particularly, diastolic blood pressure and prolactin levels were markedly associated with questionnaire items such as behaviour of the staff or nausea. Heart rate significantly correlated with anxiety scores. Helicopter transportation induced a marked stress reaction in healthy volunteers, which speaks in favour of smooth transports in modern helicopters and adequate behaviour towards the patient of the staff.

  2. Anaphylaxis syndromes related to a new mammalian cross-reactive carbohydrate determinant.

    PubMed

    Commins, Scott P; Platts-Mills, Thomas A E

    2009-10-01

    Anaphylaxis is a severe allergic reaction that can rapidly progress and occasionally be fatal. In instances in which the triggering allergen is not obvious, establishing the cause of anaphylaxis is pivotal to long-term management. Assigning cause is limited, however, by the number of known exposures associated with anaphylaxis. Therefore identification of novel causative agents can provide an important step forward in facilitating new, allergen-specific approaches to management. In contrast to the view that carbohydrate-directed IgE has minimal, if any, clinical significance, recent data suggest that IgE antibodies to carbohydrate epitopes can be an important factor in anaphylaxis that might otherwise appear to be idiopathic. Here we review the evidence relating to carbohydrates in food allergy and anaphylaxis and discuss the implications of a new mammalian cross-reactive carbohydrate determinant.

  3. Improving health-related fitness in adolescents: the CrossFit Teens™ randomised controlled trial.

    PubMed

    Eather, Narelle; Morgan, Philip James; Lubans, David Revalds

    2016-01-01

    The aim of this study was to evaluate the preliminary efficacy and feasibility of the CrossFit Teens™ resistance training programme for improving health-related fitness and resistance training skill competency in adolescents. This assessor-blinded randomised controlled trial was conducted in one secondary school in the Hunter Region, Australia, from July to September 2013. Ninety-six (96) students (age = 15.4 (.5) years, 51.5% female) were randomised into intervention (n = 51) or control (n = 45) conditions for 8-weeks (60 min twice per week). Waist circumference, body mass index (BMI), BMI-Z score (primary outcomes), cardiorespiratory fitness (shuttle run test), muscular fitness (standing jump, push-up, handgrip, curl-up test), flexibility (sit and reach) and resistance training skill competency were measured at baseline and immediate post-intervention. Feasibility measures of recruitment, retention, adherence and satisfaction were assessed. Significant group-by-time intervention effects were found for waist circumference [-3.1 cm, P < 0.001], BMI [-1.38 kg · m(‒)(2), P < 0.001], BMI-Z [-0.5 z-scores, P < 0.001], sit and reach [+3.0 cm, P < 0.001], standing jump [+0.1 m, P = 0.021] and shuttle run [+10.3 laps, P = 0.019]. Retention rate was 82.3%. All programme sessions were delivered and participants' mean satisfaction scores ranged from 4.2 to 4.6 out of 5. The findings demonstrate that CrossFit Teens™ is a feasible and efficacious programme for improving health-related fitness in adolescents.

  4. Frequencies and Associations of Narcolepsy-Related Symptoms: A Cross-Sectional Study

    PubMed Central

    Kim, Lenise Jihe; Coelho, Fernando Morgadinho; Hirotsu, Camila; Araujo, Paula; Bittencourt, Lia; Tufik, Sergio; Andersen, Monica Levy

    2015-01-01

    Objectives: Narcolepsy is a disabling disease with a delayed diagnosis. At least 3 years before the disorder identification, several comorbidities can be observed in patients with narcolepsy. The early recognition of narcolepsy symptoms may improve long-term prognosis of the patients. Thus, we aimed to investigate the prevalence of the symptoms associated with narcolepsy and its social and psychological association in a sample of Sao Paulo city inhabitants. Methods: We performed a cross-sectional evaluation with 1,008 individuals from the Sao Paulo Epidemiologic Sleep Study (EPISONO). Excessive daytime sleepiness (EDS) was assessed by the Epworth Sleepiness Scale. Volunteers were also asked about the occurrence of cataplectic-like, hypnagogic or hypnopompic hallucinations, and sleep paralysis symptoms. The participants underwent a full-night polysomnography and completed questionnaires about psychological, demographic, and quality of life parameters. Results: We observed a prevalence of 39.2% of EDS, 15.0% of cataplectic-like symptom, 9.2% of hypnagogic or hypnopompic hallucinations, and 14.9% of sleep paralysis in Sao Paulo city inhabitants. A frequency of 6.9% was observed when EDS and cataplectic-like symptoms were grouped. The other associations were EDS + hallucinations (4.7%) and EDS + sleep paralysis (7.5%). Symptomatic participants were predominantly women and younger compared with patients without any narcolepsy symptom (n = 451). Narcolepsy symptomatology was also associated with a poor quality of life and symptoms of depression, anxiety, and fatigue. Conclusions: Narcolepsy-related symptoms are associated with poor quality of life and worse psychological parameters. Citation: Kim LJ, Coelho FM, Hirotsu C, Araujo P, Bittencourt L, Tufik S, Andersen ML. Frequencies and associations of narcolepsy-related symptoms: a cross-sectional study. J Clin Sleep Med 2015;11(12):1377–1384. PMID:26235160

  5. Cysteine Cross-linking Defines the Extracellular Gate for the Leishmania donovani Nucleoside Transporter 1.1 (LdNT1.1)*

    PubMed Central

    Valdés, Raquel; Shinde, Ujwal; Landfear, Scott M.

    2012-01-01

    Equilibrative nucleoside transporters are a unique family of proteins that enable uptake of nucleosides/nucleobases into a wide range of eukaryotes and internalize a myriad of drugs used in the treatment of cancer, heart disease, AIDs, and parasitic infections. In previous work we generated a structural model for such a transporter, the LdNT1.1 nucleoside permease from the parasitic protozoan Leishmania donovani, using ab initio computation. The model suggested that aromatic residues present in transmembrane helices 1, 2, and 7 interact to form an extracellular gate that closes the permeation pathway in the inward-open conformation. Mutation of residues Phe-48TM1 and Trp-75TM2 abrogated transport activity, consistent with such prediction. In this study cysteine mutagenesis and oxidative cross-linking were combined to analyze proximity relationships of helices 1, 2, and 7 in LdNT1.1. Disulfide bond formation between introduced paired cysteines at the interface of such helices (A61CTM1/F74CTM2, A61CTM1/G350CTM7, and F74CTM2/G350CTM7) was analyzed by transport measurement and gel mobility shifts upon oxidation with Cu (II)-(1,10-phenanthroline)3. In all cases cross-linking inhibited transport. However, if LdNT1.1 ligands were included during cross-linking, inhibition of transport was reduced, suggesting that ligands moved the three gating helices apart. Moreover, all paired cysteine mutants exhibited a mobility shift upon oxidation, corroborating the formation of a disulfide bond. These data support the notion that helices 1, 2, and 7 constitute the extracellular gate of LdNT1.1, thus further validating the computational model and the previously demonstrated importance of F48TM1 and Trp-75TM2 in tethering together helices that are part of the gate. PMID:23150661

  6. Street-Crossing Decision-Making: A Comparison between Patients with Age-Related Macular Degeneration and Normal Vision

    PubMed Central

    Hassan, Shirin E.; Snyder, Benjamin D.

    2012-01-01

    Purpose. We determined whether the street-crossing decisions of subjects with age-related macular degeneration (AMD) were as accurate and precise as those made by young and older subjects with normal vision. Methods. Street-crossing decisions in 13 AMD subjects, and 20 young and 20 older control subjects with normal vision were measured along an un-signalized street for nine different gap times. After calculating the discriminability (d') of the street-crossing decision variable for all gap pairs and entering these d' values into a one-dimensional scaling model, the means of each distribution of the decision variable relative to a “center of gravity” were estimated and plotted against gap time. The resultant plot was a nonlinear function. Street-crossing decision accuracy was computed for each subject as the difference between the x-intercept of the nonlinear function (tCOG) and subjects' measured street-crossing time. Street-crossing decision-making precision was computed as the value of the slope of the nonlinear function at tCOG. Results. We found that all subjects were precise in their street-crossing decisions (P = 0.55). Significant differences in street-crossing accuracy were found as a function of age (P = 0.003). Compared to either the older normally-sighted (P = 0.018) or AMD (P = 0.019) subjects, the young normally-sighted subjects made the least accurate street-crossing decisions. No significant difference in accuracy was found between the AMD and age-matched normally-sighted subjects (P = 0.90). Conclusions. Our data suggested that age and mild central vision loss did not affect significantly a subject's precision in their street-crossing decisions. Age, but not mild central vision loss, significantly affected a subject's accuracy in their street-crossing decisions. PMID:22899756

  7. Body weight concerns: Cross-national study and identification of factors related to eating disorders

    PubMed Central

    da Silva, Wanderson Roberto; Santana, Moema de Souza; Maroco, João; Maloa, Benvindo Felismino Samuel

    2017-01-01

    Background Body weight concerns are common among individuals with eating disorders, and this construct can be assessed using psychometric instruments. The Weight Concerns Scale (WCS) is commonly used to assess body weight concerns. Aims To evaluate the psychometric properties of the WCS with Brazilian, Portuguese, and Mozambican female college students; to estimate body weight concerns; and to identify factors related to eating disorders. Methods Confirmatory factor analysis was performed. Factorial, convergent, concurrent, and divergent validity, as well as reliability, were assessed. Cross-national invariance was tested by means of multigroup analysis. Structural models were tested using the WCS as the dependent variable, while demographic and academic variables and body mass index were used as independent variables. Logistic models were tested to estimate the likelihood of eating disorders being developed in specific groups. Results Participants were 2,068 female students. The psychometric properties of the WCS were adequate for the Portuguese sample; however, for the Brazilian and Mozambican samples, it was necessary to correlate the errors of two items to improve model fit. The WCS did not show cross-national invariance. The variables “thoughts about dropping out of college,” “medication use because of studies,” “medication and supplements use for body change,” “body mass index,” “socioeconomic status,” “age,” and “performance in course” were significant predictors of body weight concerns. Overall, 24.4% (95% confidence interval = 22.9–26.7) of the students were likely to develop eating disorders. Students under 21 years old, who use medication and supplements for body change, and who were classified as overweight/obese have increased likelihood of developing eating disorders. Conclusion The WCS showed good psychometric properties with Brazilian, Portuguese, and Mozambican students; however, it did not show cross

  8. Cross-bedding Related Anisotropy and its Role in the Orientation of Joints in an Aeolian Sandstone

    NASA Astrophysics Data System (ADS)

    Deng, S.; Cilona, A.; Mapeli, C.; Panfilau, A.; Aydin, A.; Prasad, M.

    2014-12-01

    Previous research revealed that the cross-bedding related anisotropy in aeolian sandstones affects the orientation of compaction bands, also known as anticracks. We hypothesize that cross-bedding should a have similar influence on the orientation of the joints within the same rock at the same location. To test this hypothesis, we investigated the relationship between the cross-beds and the cross-bed package confined joints in the Jurassic aeolian Aztec Sandstone cropping out in the Valley of Fire State Park, Nevada. The field data demonstrates that the cross-bed package confined joints occur at high-angle to bedding and trend roughly parallel to the dip direction of the cross-beds. This shows that the cross-bed orientation and the associated anisotropy also exert a strong control on the formation and orientation of the joints. In order to characterize the anisotropy due to cross-bedding in the Aztec Sandstone, we measured the P-wave velocities parallel and perpendicular to bedding from 11 samples in the laboratory using a bench-top ultrasonic assembly. The measured P-wave anisotropy is about 13% on average. Based on these results, a numerical model based on the generalized Hooke's law for anisotropic materials is analyzed assuming the cross-bedded sandstone to be transversely isotropic. Using this model, we tested various cross-bed orientations as well as different strain boundary conditions (uniaxial, axisymmetric and triaxial). It is possible to define a boundary condition under which the modeled results roughly match with the observed relationship between cross-bed package confined joints and cross-beds. These results have important implications for fluid flow through aeolian sandstones in reservoirs and aquifers.

  9. What is the role of laminar cirrus cloud on regulating the cross-tropopause water vapor transport?

    NASA Astrophysics Data System (ADS)

    Wu, D. L.; Gong, J.; Tsai, V.

    2016-12-01

    Laminar cirrus is an extremely thin ice cloud found persistently inhabit in the tropical and subtropical tropopause. Due to its sub-visible optical depth and high formation altitude, knowledge about the characteristics of this special type of cloud is very limited, and debates are ongoing about its role on regulating the cross-tropopause transport of water vapor. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite has been continuously providing us with unprecedented details of the laminar cirrus since its launch in 2006. In this research, we adapted Winker and Trepte (1998)'s eyeball detection method. A JAVA-based applet and graphical user interface (GUI) is developed to manually select the laminar, which then automatically record the cloud properties, such as spatial location, shape, thickness, tilt angle, and whether its isolated or directly above a deep convective cloud. Monthly statistics of the laminar cirrus are then separately analyzed according to the orbit node, isolated/convective, banded/non-banded, etc. Monthly statistics support a diurnal difference in the occurring frequency and formation height of the laminar cirrus. Also, isolated and convective laminars show diverse behaviors (height, location, distribution, etc.), which strongly implies that their formation mechanisms and their roles on depleting the upper troposphere water vapor are distinct. We further study the relationship between laminar characteristics and collocated and coincident water vapor gradient measurements from Aura Microwave Limb Sounder (MLS) observations below and above the laminars. The identified relationship provides a quantitative answer to the role laminar cirrus plays on regulating the water vapor entering the stratosphere.

  10. Ion channels and transporters in cancer. 3. Ion channels in the tumor cell-microenvironment cross talk.

    PubMed

    Arcangeli, Annarosa

    2011-10-01

    The traditional view of cancer as a collection of proliferating cells must be reconsidered, and cancer must be viewed as a "tissue" constituted by both transformed cells and a heterogeneous microenvironment, that tumor cells construct and remodel during multistep tumorigenesis. The "tumor microenvironment" (TM) is formed by mesenchymal, endothelial, and immune cells immersed in a network of extracellular matrix (ECM) proteins and soluble factors. The TM strongly contributes to tumor progression, through long distance, cell-to-cell or cell-to-matrix signals, which influence different aspects of tumor cell behavior. Understanding the relationships among the different components of the cancer tissue is crucial to design and develop new therapeutic strategies. Ion channels are emerging as relevant players in the cross talk between tumor cells and their TM. Ion channels are expressed on tumor cells, as well as in the different cellular components of the TM. In all these cells, ion channels are in a strategic position to sense and transmit extracellular signals into the intracellular machinery. Often, this transmission is mediated by integrin adhesion receptors, which can be functional partners of ion channels since they form molecular complexes with the channel protein in the context of the plasma membrane. The same relevant role is exerted by ion transporters, which also contribute to determine two facets of the cancer tissue: hypoxia and the acidic extracellular pH. On the whole, it is conceivable to prospect the targeting of ion channels for new therapeutic strategies aimed at better controlling the malignant progression of the cancer tissue.

  11. An evolutionary attractor model for sapwood cross section in relation to leaf area.

    PubMed

    Westoby, Mark; Cornwell, William K; Falster, Daniel S

    2012-06-21

    Sapwood cross-sectional area per unit leaf area (SA:LA) is an influential trait that plants coordinate with physical environment and with other traits. We develop theory for SA:LA and also for root surface area per leaf area (RA:LA) on the premise that plants maximizing the surplus of revenue over costs should have competitive advantage. SA:LA is predicted to increase in water-relations environments that reduce photosynthetic revenue, including low soil water potential, high water vapor pressure deficit (VPD), and low atmospheric CO(2). Because sapwood has costs, SA:LA adjustment does not completely offset difficult water relations. Where sapwood costs are large, as in tall plants, optimal SA:LA may actually decline with (say) high VPD. Large soil-to-root resistance caps the benefits that can be obtained from increasing SA:LA. Where a plant can adjust water-absorbing surface area of root per leaf area (RA:LA) as well as SA:LA, optimal RA:SA is not affected by VPD, CO(2) or plant height. If selection favours increased height more so than increased revenue-minus-cost, then height is predicted to rise substantially under improved water-relations environments such as high-CO(2) atmospheres. Evolutionary-attractor theory for SA:LA and RA:LA complements models that take whole-plant conductivity per leaf area as a parameter. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Age-related differences in hair trace elements: a cross-sectional study in Orenburg, Russia.

    PubMed

    Skalnaya, Margarita G; Tinkov, Alexey A; Demidov, Vasily A; Serebryansky, Eugeny P; Nikonorov, Alexandr A; Skalny, Anatoly V

    2016-09-01

    Age-related differences in the trace element content of hair have been reported. However, some discrepancies in the data exist. The primary objective of this study was to estimate the change in hair trace elements content in relation to age. Six hundred and eighteen women and 438 men aged from 10-59 years took part in the current cross-sectional study. Hair Cr, Mn, Ni, Si, Al, As, Be, Cd and Pb tended to decrease with age in the female sample, whereas hair Cu, Fe, I, Se, Li and Sn were characterised by an age-associated increase. Hair levels of Cr, Cu, I, Mn, Ni, Si and Al in men decreased with age, whereas hair Co, Fe, Se, Cd, Li and Pb content tended to increase. Hair mercury increased in association with age in men and in women, whereas hair vanadium was characterised by a significant decrease in both sexes. The difference in hair trace element content between men and women decreased with age. These data suggest that age-related differences in trace element status may have a direct implication in the ageing process.

  13. Is Nurses' Professional Competence Related to Their Personality and Emotional Intelligence? A Cross-Sectional Study

    PubMed Central

    Heydari, Abbas; Kareshki, Hossein; Armat, Mohammad Reza

    2016-01-01

    Introduction: Nurses' professional competence is a crucial factor in clinical practice. Systematic evaluation of nurses’ competence and its related factors are essential for enhancing the quality of nursing care. This study aimed to assess the nurses’ competence level and its possible relationship with their personality and emotional intelligence. Methods: Using a cross-sectional survey design, three instruments including Nurse Competence Scale, short form of Schutte Self Report Emotional Intelligence Test, and the short 10-item version of Big Five Factor Inventory, were administered simultaneously to a randomized stratified sample of 220 nurses working in hospitals affiliated to Mashhad University of Medical Sciences. Data analysis was performed using SPSS 11.5. Results: Majority of nurses rated themselves as "good" and "very good", with the highest scores in "managing situations" and "work role" dimensions of nurse competence. A relatively similar pattern of scores was seen in competence dimensions, personality and emotional intelligence, among male and female nurses. Emotional intelligence and personality scores showed a significant relationship with nurses’ competence, explaining almost 20% of variations in nurse competence scores. Conclusion: Iranian nurses evaluated their overall professional competence at similar level of the nurses in other countries. Knowledge about the nurses’ competence level and its related factors, including personality and emotional intelligence, may help nurse managers in enhancing nurses' professional competence through appropriate task assignments and conducting in-service educational programs, thus improving the health status of patients. PMID:27354976

  14. Is Nurses' Professional Competence Related to Their Personality and Emotional Intelligence? A Cross-Sectional Study.

    PubMed

    Heydari, Abbas; Kareshki, Hossein; Armat, Mohammad Reza

    2016-01-01

    Nurses' professional competence is a crucial factor in clinical practice. Systematic evaluation of nurses' competence and its related factors are essential for enhancing the quality of nursing care. This study aimed to assess the nurses' competence level and its possible relationship with their personality and emotional intelligence. Using a cross-sectional survey design, three instruments including Nurse Competence Scale, short form of Schutte Self Report Emotional Intelligence Test, and the short 10-item version of Big Five Factor Inventory, were administered simultaneously to a randomized stratified sample of 220 nurses working in hospitals affiliated to Mashhad University of Medical Sciences. Data analysis was performed using SPSS 11.5. Majority of nurses rated themselves as "good" and "very good", with the highest scores in "managing situations" and "work role" dimensions of nurse competence. A relatively similar pattern of scores was seen in competence dimensions, personality and emotional intelligence, among male and female nurses. Emotional intelligence and personality scores showed a significant relationship with nurses' competence, explaining almost 20% of variations in nurse competence scores. Iranian nurses evaluated their overall professional competence at similar level of the nurses in other countries. Knowledge about the nurses' competence level and its related factors, including personality and emotional intelligence, may help nurse managers in enhancing nurses' professional competence through appropriate task assignments and conducting in-service educational programs, thus improving the health status of patients.

  15. Age-related differences in emotion recognition ability: a cross-sectional study.

    PubMed

    Mill, Aire; Allik, Jüri; Realo, Anu; Valk, Raivo

    2009-10-01

    Experimental studies indicate that recognition of emotions, particularly negative emotions, decreases with age. However, there is no consensus at which age the decrease in emotion recognition begins, how selective this is to negative emotions, and whether this applies to both facial and vocal expression. In the current cross-sectional study, 607 participants ranging in age from 18 to 84 years (mean age = 32.6 +/- 14.9 years) were asked to recognize emotions expressed either facially or vocally. In general, older participants were found to be less accurate at recognizing emotions, with the most distinctive age difference pertaining to a certain group of negative emotions. Both modalities revealed an age-related decline in the recognition of sadness and -- to a lesser degree -- anger, starting at about 30 years of age. Although age-related differences in the recognition of expression of emotion were not mediated by personality traits, 2 of the Big 5 traits, openness and conscientiousness, made an independent contribution to emotion-recognition performance. Implications of age-related differences in facial and vocal emotion expression and early onset of the selective decrease in emotion recognition are discussed in terms of previous findings and relevant theoretical models.

  16. Differential, total, and transport cross sections for elastic scattering of low energy positrons by neutral atoms (Z = 1--92, E = 500--4000 eV)

    SciTech Connect

    Dapor, M. |; Miotello, A. |

    1998-05-01

    The authors present tables of the differential, total, and transport cross sections for the elastic scattering of 500--4000 eV positrons by neutral atoms in the atomic number range Z = 1--92. The cross sections were computed by numerically solving the Dirac equation for a central electrostatic field up to a large radius where the atomic potential becomes negligible. The atomic potential used was Hartree-Fock for Z = 1--18 and Dirac-Hartree-Fock-Slater for Z = 19--92.

  17. Dual Mechanisms of Ion Absorption in Relation to Long Distance Transport in Plants

    PubMed Central

    Luttge, Ulrich; Laties, George G.

    1966-01-01

    The characteristics of ion transport to the shoots of young corn seedlings were studied with respect to the nature of the isotherm through a wide concentration range, the competitive influence of closely related ions upon the transport of a given ion, and the influence of the counter-ion. Both with respect to 36Cl and 86Rb transport, the characteristics of the process in every way resemble uptake by non-vacuolate root tips wherein the plasma membrane is the only membrane involved in absorption, and where system 1 — of the 2 systems which can be shown to participate in absorption by vacuolate tissue — is the only system operative. Net ion uptake by the roots per se was shown to display both the high affinity (system 1) and low affinity (system 2) mechanisms. It is concluded that the symplastic theory of ion movement to the xylem is valid, and that the contention that system 1 operates at the plasma membrane while system 2 functions at the tonoplast is strengthened. PMID:16656435

  18. Relation between inhomogeneous structure and transport properties for superconductor-insulator transitions

    NASA Astrophysics Data System (ADS)

    Komaki, S.; Sawada, Y.; Saya, B.; Ichikawa, F.; Itoh, K.; Makise, K.

    2009-03-01

    In the study of superconductor-insulator transitions of high-Tc cuprates complicated behaviors in transport properties were observed for example quasi-reentrant behaviors. In this study we report that the relation between microscopic structure and transport properties for Bi2Sr2CaCu2O8+y crystal with substitution of Ca by Y. From the energy dispersive X-ray spectroscopy it was estimated that samples contain almost 45% Y when the starting composition was only 10% Y. Also the values of c-axis length were almost constant and shorter than those of Y free samples. However there were various ρ(T) behaviors dependent on sample: localized, quasi-reentrant, broad superconducting transition etc. All sheet resistances defined per CuO2 bilayer in the normal state were much larger than the quantum resistance h/4e2 or 6450 Ω. We were able to observe the inhomogeneous distribution of Y using a combination of electron energy loss spectroscopy and a high-angle annular dark-field technique in a scanning transmission electron microscope. The Y rich region formed the belt with about 20 nm width. This inhomogeneous structure seems to be the origin of various transport properties.

  19. Edible mushroom-related poisoning: A study on circumstances of mushroom collection, transport, and storage.

    PubMed

    Gawlikowski, T; Romek, M; Satora, L

    2015-07-01

    The American Association of Poison Control Center (AAPCC) shows that in 2012 there were 0.3% of human exposures involving mushrooms. Only 17% of 6600 cases were then identified by the species. The present retrospective study was designed to identify the epidemiology of mushroom poisoning in adults admitted to Krakow's Department of Clinical Toxicology (DCT) from 2002 to 2009. This study was conducted retrospectively after examining the files of 457 adult patients with wild mushroom poisoning. Mycological analysis was made and the species of the poisoning-inducing mushroom was determined. Furthermore, the circumstances related to the mushroom gathering, transport, storage, preparation, and consumption have been analyzed. The analysis revealed that in 400 (87.53%) out of 457 cases, the clinical symptoms were caused by ingestion of identified edible mushroom species. The main reason for edible mushroom poisoning is associated with their incorrect processing after harvest. The analysis of the circumstances of mushroom collection, transport, and storage shows that the largest percentage of poisoning was connected with long-term storage of mushroom dishes, collecting, and storing them in plastic bags, and long storage of mushrooms. Based on spore analysis of the gastric content, edible mushrooms were responsible for the great majority of mushroom poisoning cases admitted to the DCT. The toxicity of edible mushroom is associated with proceeding with them during collection, transport, and storage. The medical history should be supplemented by questions concerning these circumstances. The identification of the mushroom by a mycologist is highly desirable. © The Author(s) 2014.

  20. OSBP-Related Protein Family in Lipid Transport Over Membrane Contact Sites

    PubMed Central

    Olkkonen, Vesa M.

    2015-01-01

    Increasing evidence suggests that oxysterol-binding protein-related proteins (ORPs) localize at membrane contact sites, which are high-capacity platforms for inter-organelle exchange of small molecules and information. ORPs can simultaneously associate with the two apposed membranes and transfer lipids across the interbilayer gap. Oxysterol-binding protein moves cholesterol from the endoplasmic reticulum to trans-Golgi, driven by the retrograde transport of phosphatidylinositol-4-phosphate (PI4P). Analogously, yeast Osh6p mediates the transport of phosphatidylserine from the endoplasmic reticulum to the plasma membrane in exchange for PI4P, and ORP5 and -8 are suggested to execute similar functions in mammalian cells. ORPs may share the capacity to bind PI4P within their ligand-binding domain, prompting the hypothesis that bidirectional transport of a phosphoinositide and another lipid may be a common theme among the protein family. This model, however, needs more experimental support and does not exclude a function of ORPs in lipid signaling. PMID:26715851

  1. Periplasmic protein related to the sn-glycerol-3-phosphate transport system of Escherichia coli.

    PubMed Central

    Silhavy, T J; Hartig-Beecken, I; Boos, W

    1976-01-01

    Two-dimensional gel electrophoresis of shock fluids of Escherichia coli K-12 revealed the presence of a periplasmic protein related to sn-glycerol-3-phosphate transport (GLPT) that is under the regulation of glpR, the regulatory gene of the glp regulon. Mutants selected for their resistance to phosphonomycin and found to be defective in sn-glycerol-3-phosphate transport either did not produce GLPT or produced it in reduced amounts. Other mutations exhibited no apparent effect of GLPT. Transductions of glpT+ nalA phage P1 into these mutants and selection for growth on sn-glycerol-3-phosphate revealed a 50% cotransduction frequency to nalA. Reversion of mutants taht did not produce GLPT to growth on sn-glycerol-3-phosphate resulted in strains that produce GLPT. This suggests a close relationship of GLPT to the glpT gene and to sn-glycerol-3-phosphate transport. Attempts to demonstrate binding activity of GLPT in crude shock fluid towards sn-glycerol-3-phosphate have failed so far. However, all shock fluids, independent of their GLPT content, exhibited an enzymatic activity that hydrolyzes under the conditions of the binding assay, 30 to 60% of the sn-glycerol-3-phosphate to glycerol and inorganic orthophosphate. Images PMID:770459

  2. The cross-sectional relation between medically unexplained physical symptoms (MUPS) and the Cortisol Awakening Response.

    PubMed

    Claassen-van Dessel, Nikki; van der Wouden, Johannes C; Dekker, Joost; Rosmalen, Judith G M; van der Horst, Henriëtte E

    2017-08-01

    We aimed to assess the cross-sectional relation between levels of cortisol and specific symptom clusters, symptom severity and duration of symptoms in patients with medically unexplained physical symptoms (MUPS). Baseline data of a cohort of MUPS patients were used. We chose the Cortisol Awakening Response (CAR) as a cortisol parameter, using saliva samples. We used confirmatory factor analysis for the identification of 4 specific symptom clusters: (1) gastro-intestinal symptoms; (2) pain; (3) cardio-pulmonary symptoms; and (4) fatigue. For this factor analysis we used the Physical Symptom Questionnaire (PSQ), which assesses the occurrence and frequency of 51 physical symptoms. Symptom severity was measured with the Patient Health Questionnaire-15 (PHQ-15). Duration of symptoms was based on self-reported duration of top 3 symptoms. We performed multiple linear regression to assess relations between CAR and individual factor scores on symptom clusters, symptom severity and duration of symptoms. Data from 296 patients (76% female) were included in the analyses. The majority of patients suffered from symptoms in multiple organ systems. Factor analysis confirmed that the model with 4 symptom clusters fitted our data. For the total study population, we found no significant relation between CAR and participants' factor scores on any of the symptom clusters. We also found no significant relations between CAR and severity or duration of symptoms. Our results suggest that within a heterogeneous MUPS population there is no relation between CAR and symptom severity and duration. However, more studies are needed to confirm our findings. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Associations between health culture, health behaviors, and health-related outcomes: A cross-sectional study

    PubMed Central

    Jia, Yingnan; Gao, Junling; Dai, Junming; Zheng, Pinpin

    2017-01-01

    Background To examine the associations between demographic characteristics, health behaviors, workplace health culture, and health-related outcomes in Chinese workplaces. Methods A total of 1508 employees from 10 administrative offices and 6 enterprises were recruited for a cross-sectional survey. Self-administered questionnaires mainly addressed demographic characteristics, health behaviors, workplace health culture, and health-related outcomes including self-rated health, mental health, and happiness. Results The proportion of participants who reported good health-related outcomes was significantly higher in those working in administrative offices than those working in enterprises. The result of the potential factors related to self-rated health (SRH), mental health, and happiness by logistic regression analyses showed that age and income were associated with SRH; type of workplace, age, smoking, and health culture at the workplace level were associated with mental health; and beneficial health effects of direct leadership was positively associated with happiness. Moreover, there were some similar results among 3 multivariate regression models. Firstly, good SRH (Odds Ratio (OR) = 1.744), mental health (OR = 1.891), and happiness (OR = 1.736) were more common among highly physically active participants compared with those physical inactive. Furthermore, passive smoking was negatively correlated with SRH (OR = 0.686), mental health (OR = 0.678), and happiness (OR = 0.616), while health culture at the individual level was positively correlated with SRH (OR = 1.478), mental health (OR = 1.654), and happiness (OR = 2.916). Conclusions The present study indicated that workplace health culture, health behaviors, and demographic characteristics were associated with health-related outcomes. Furthermore, individual health culture, physical activity, and passive smoking might play a critical role in workplace health promotion. PMID:28746400

  4. Associations between health culture, health behaviors, and health-related outcomes: A cross-sectional study.

    PubMed

    Jia, Yingnan; Gao, Junling; Dai, Junming; Zheng, Pinpin; Fu, Hua

    2017-01-01

    To examine the associations between demographic characteristics, health behaviors, workplace health culture, and health-related outcomes in Chinese workplaces. A total of 1508 employees from 10 administrative offices and 6 enterprises were recruited for a cross-sectional survey. Self-administered questionnaires mainly addressed demographic characteristics, health behaviors, workplace health culture, and health-related outcomes including self-rated health, mental health, and happiness. The proportion of participants who reported good health-related outcomes was significantly higher in those working in administrative offices than those working in enterprises. The result of the potential factors related to self-rated health (SRH), mental health, and happiness by logistic regression analyses showed that age and income were associated with SRH; type of workplace, age, smoking, and health culture at the workplace level were associated with mental health; and beneficial health effects of direct leadership was positively associated with happiness. Moreover, there were some similar results among 3 multivariate regression models. Firstly, good SRH (Odds Ratio (OR) = 1.744), mental health (OR = 1.891), and happiness (OR = 1.736) were more common among highly physically active participants compared with those physical inactive. Furthermore, passive smoking was negatively correlated with SRH (OR = 0.686), mental health (OR = 0.678), and happiness (OR = 0.616), while health culture at the individual level was positively correlated with SRH (OR = 1.478), mental health (OR = 1.654), and happiness (OR = 2.916). The present study indicated that workplace health culture, health behaviors, and demographic characteristics were associated with health-related outcomes. Furthermore, individual health culture, physical activity, and passive smoking might play a critical role in workplace health promotion.

  5. Review: Selenium contamination, fate, and reactive transport in groundwater in relation to human health

    NASA Astrophysics Data System (ADS)

    Bailey, Ryan T.

    2016-12-01

    Selenium (Se) is an essential micro-nutrient for humans, but can be toxic at high levels of intake. Se deficiency and Se toxicity are linked with serious diseases, with some regions worldwide experiencing Se deficiency due to Se-poor rocks and soils and other areas dealing with Se toxicity due to the presence of Se-enriched geologic materials. In addition, Se is consumed primarily through plants that take up Se from soil and through animal products that consume these plants. Hence, the soil and groundwater system play important roles in determining the effect of Se on human health. This paper reviews current understanding of Se fate and transport in soil and groundwater systems and its relation to human health, with a focus on alluvial systems, soil systems, and the interface between alluvial systems and Cretaceous shale that release Se via oxidation processes. The review focuses first on the relation between Se and human health, followed by a summary of Se distribution in soil-aquifer systems, with an emphasis on the quantitative relationship between Se content in soil and Se concentration in underlying groundwater. The physical, chemical, and microbial processes that govern Se fate and transport in subsurface systems then are presented, followed by numerical modeling techniques used to simulate these processes in study regions and available remediation strategies for either Se-deficient or Se-toxic regions. This paper can serve as a guide to any field, laboratory or modeling study aimed at assessing Se fate and transport in groundwater systems and its relation to human health.

  6. Review: Selenium contamination, fate, and reactive transport in groundwater in relation to human health

    NASA Astrophysics Data System (ADS)

    Bailey, Ryan T.

    2017-06-01

    Selenium (Se) is an essential micro-nutrient for humans, but can be toxic at high levels of intake. Se deficiency and Se toxicity are linked with serious diseases, with some regions worldwide experiencing Se deficiency due to Se-poor rocks and soils and other areas dealing with Se toxicity due to the presence of Se-enriched geologic materials. In addition, Se is consumed primarily through plants that take up Se from soil and through animal products that consume these plants. Hence, the soil and groundwater system play important roles in determining the effect of Se on human health. This paper reviews current understanding of Se fate and transport in soil and groundwater systems and its relation to human health, with a focus on alluvial systems, soil systems, and the interface between alluvial systems and Cretaceous shale that release Se via oxidation processes. The review focuses first on the relation between Se and human health, followed by a summary of Se distribution in soil-aquifer systems, with an emphasis on the quantitative relationship between Se content in soil and Se concentration in underlying groundwater. The physical, chemical, and microbial processes that govern Se fate and transport in subsurface systems then are presented, followed by numerical modeling techniques used to simulate these processes in study regions and available remediation strategies for either Se-deficient or Se-toxic regions. This paper can serve as a guide to any field, laboratory or modeling study aimed at assessing Se fate and transport in groundwater systems and its relation to human health.

  7. Modeling strongly coupled quark gluon plasmas: hydro vs transport vs general relativity

    NASA Astrophysics Data System (ADS)

    Gyulassy, Miklos

    2008-04-01

    The discovery of near perfect fluid flow and very high jet opacity in nuclear collisions at 200 AGeV at RHIC/BNL have challenged traditional weak coupling perturbative QCD modeling of quark gluon plasmas. A critical assessment of current theoretical uncertainties facing competing approaches based on relativistic hydrodynamics, quasi-parton transport dynamics, and novel string theory inspired general relativity modeling will be presented. Special focus will be on identified (charm and bottom) heavy quark jets that will serve as powerful probes in upcoming RHIC and LHC experiments to better constrain the initial conditions as well as energy loss mechanisms leading to rapid equilibration in ultra-relativistic nuclear collisions.

  8. Simultaneous evaluation of interrelated cross sections by generalized least-squares and related data file requirements

    SciTech Connect

    Poenitz, W.P.

    1984-10-25

    Though several cross sections have been designated as standards, they are not basic units and are interrelated by ratio measurements. Moreover, as such interactions as /sup 6/Li + n and /sup 10/B + n involve only two and three cross sections respectively, total cross section data become useful for the evaluation process. The problem can be resolved by a simultaneous evaluation of the available absolute and shape data for cross sections, ratios, sums, and average cross sections by generalized least-squares. A data file is required for such evaluation which contains the originally measured quantities and their uncertainty components. Establishing such a file is a substantial task because data were frequently reported as absolute cross sections where ratios were measured without sufficient information on which reference cross section and which normalization were utilized. Reporting of uncertainties is often missing or incomplete. The requirements for data reporting will be discussed.

  9. Synopsis of some preliminary computational studies related to unsaturated zone transport at Area G

    SciTech Connect

    Vold, E.

    1998-03-01

    Computational transport models are described with applications in three problem areas related to unsaturated zone moisture movement beneath Area G. These studies may be used to support the ongoing maintenance of the site Performance Assessment. The three areas include: a 1-D transient analysis with average tuff hydraulic properties in the near surface region with computed results compared to field data; the influence on near surface transient moisture percolation due to realistic distributions in hydraulic properties derived statistically from the observed variance in the field data; and the west to east moisture flow in a 2-D steady geometry approximation of the Pajarito Plateau. Results indicate that a simple transient model for transport of moisture volume fraction fits field data well compared to a moisture pulse observed in the active disposal unit, pit 37. Using realistic infiltration boundary conditions for summer showers and for spring snow melt conditions, the computed moisture pulses show significant propagation to less than 10-ft depth. Next, the hydraulic properties were varied on a 2-D grid using statistical distributions based on the field data means and variances for the hydraulic parameters. Near surface transient percolation in these conditions shows a qualitatively realistic percolation with a spatially variable wave front moving into the tuff; however, the flow does not channel into preferred paths and suggests there is no formation of fast paths which could enhance transportation of contaminants. Finally, moisture transport is modeled through an unsaturated 2-D slice representing the upper stratigraphic layers beneath Area G and a west-to-east cut of several miles to examine possible lateral movement from the west where percolation is assumed to be greater than at Area G. Results show some west-to-east moisture flux consistent with the assumed profile for the percolation boundary conditions.

  10. Meta-analysis of expression of hepatic organic anion-transporting polypeptide (OATP) transporters in cellular systems relative to human liver tissue.

    PubMed

    Badée, Justine; Achour, Brahim; Rostami-Hodjegan, Amin; Galetin, Aleksandra

    2015-04-01

    Organic anion-transporting polypeptide (OATP)1B1, OATP1B3, and OATP2B1 transporters play an important role in hepatic drug disposition. Recently, an increasing number of studies have reported proteomic expression data for OATP transporters. However, systematic analysis and understanding of the actual differences in OATP expression between liver tissue and commonly used cellular systems is lacking. In the current study, meta-analysis was performed to assess the protein expression of OATP transporters reported in hepatocytes relative to liver tissue and to identify any potential correlations in transporter expression levels in the same individual. OATP1B1 was identified as the most abundant uptake transporter at 5.9 ± 8.3, 5.8 ± 3.3, and 4.2 ± 1.7 fmol/μg protein in liver tissue, sandwich-cultured human hepatocytes (SCHH), and cryopreserved suspended hepatocytes, respectively. The rank order in average expression in liver tissue and cellular systems was OATP1B1 > OATP1B3 ≈ OATP2B1. Abundance levels of the OATP transporters investigated were not significantly different between liver and cellular systems, with the exception of OATP2B1 expression in SCHH relative to liver tissue. Analysis of OATP1B1, OATP1B3, and OATP2B1 liver expression data in the same individuals (n = 86) identified weak (OATP1B1-OATP2B1) to moderately (OATP1B3-OATP2B1) significant correlations. A significant weak correlation was noted between OATP1B1 abundance and age of human donors, whereas expression of the OATPs investigated was independent of sex. Implications of the current analysis on the in vitro-in vivo extrapolation of transporter-mediated drug disposition using physiologically based pharmacokinetic models are discussed. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  11. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM Miscellaneous Provisions Hazardous and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating...

  12. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM Miscellaneous Provisions Hazardous and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating...

  13. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM Miscellaneous Provisions Hazardous and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating...

  14. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM Miscellaneous Provisions Hazardous and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating...

  15. Hygrothermal Properties of Cross Laminated Timber and Moisture Response of Wood at High Relative Humidity

    NASA Astrophysics Data System (ADS)

    AlSayegh, George

    Cross Laminated Timber (CLT) is a new wood-based material composed of cross laminated wood boards that form a structural panel. This study focuses on identifying the appropriate methods to determine the hygrothermal properties of CLTs fabricated with Canadian and European Lumber. The laboratory tests carried out in this study will help establish heat, air and moisture response properties to be used for hygrothermal simulation to assess the durability of CLTs in building envelope construction. Measurement of water vapour permeability, liquid water absorption, sorption isotherms, thermal conductivity, and air permeability were performed on three Canadian CLT specimens composed of Hem-Fir, Eastern Spruce-Pine-Fir, and Western Spruce-Pine-Fir and one European specimen composed of Spruce. The hygrothermal properties of CLT, considered in this study, appear to be similar to commonly used wood specimens reported in the literature. However, liquid water absorption coefficients of CLT were found to be generally lower than common wood species, possibly due to the presence of glue between the wood layers which limits the moisture movement across the specimen. On the other hand, the air permeability across the CLT specimens varied due to the glue discontinuity within the specimen which led some CLTs to be permeable, however all the European specimens were found to be impermeable. This study also critically analyzed the significance of equilibrium moisture content (EMC) of wood at high relative humidity, measured by means of a pressure plate apparatus and humidity chambers, on the moisture management performance of a wood-frame stucco wall, using the hygrothermal simulation tool hygIRC-2D. The simulation results indicate that the prediction of the moisture response of a wood-frame stucco wall assembly depends significantly on the method adopted to derive the EMC of wood at high RH.

  16. Integrating health-related quality of life into cross-national clinical trials.

    PubMed

    Cella, D F; Wiklund, I; Shumaker, S A; Aaronson, N K

    1993-12-01

    When planning to implement health-related quality of life (HRQL) assessment in a multinational clinical trial, there are at least four general considerations: the natural history of the disease or condition, the characteristics of the population, the treatment under consideration, and the structure and function of the clinical trial organization. Each of these considerations must be addressed simultaneously when planning, implementing and analysing a cross-national clinical trial. There are five relevant polar components of the natural history of a given disease or condition: (1) time frame (acute versus chronic); (2) life threat (yes versus no); (3) symptomatology (present versus absent); (4) symptom expression (episodic versus constant); and (5) functional impact (present versus absent). Differences in population characteristics, (e.g., age, conditions, co-morbidity), embedded within any cross-national trial, must be addressed conceptually prior to initiating the trial, methodologically when planning implementation, and statistically after the collection of the data. In terms of treatment, issues such as adverse and positive effects and timing of effects must be considered. The methods entailed in planning, implementing and analysing HRQL data will depend upon the degree of centralization of personnel and resources within any given clinical trial. The range of possibilities runs from complete centralization, in which all planning and coordination of data collection and transmittal is done by one office, to complete decentralization, in which the work is distributed to participating sites and interested investigators. Finally, successful implementation of HRQL data collection is enhanced by heightening awareness of the importance of, and value in, assessing HRQL in clinical trials.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Relation of smoking and alcohol and coffee consumption to active Helicobacter pylori infection: cross sectional study.

    PubMed Central

    Brenner, H.; Rothenbacher, D.; Bode, G.; Adler, G.

    1997-01-01

    OBJECTIVE: To assess the relation of smoking and alcohol and coffee consumption to active Helicobacter pylori infection. DESIGN: Cross sectional study of patients attending a general practitioner. Active H pylori infection was measured by the 15C-urea breath test and detailed quantitative information on smoking and on alcohol and coffee consumption was obtained by a standardised self administered questionnaire. SETTING: One general practice in Germany. SUBJECTS: 447 patients aged 15-79 who had not had peptic ulcer disease or treatment for H pylori infection. MAIN OUTCOME MEASURES: Prevalence of H pylori infection according to smoking and alcohol and coffee consumption. RESULTS: Overall prevalence of infection was 21% (94/447). There was no significant relation between smoking and active H pylori infection. Alcohol consumption showed a negative dose-response relation and coffee consumption a positive dose-response relation with active infection. After adjustment for potential confounders, the odds ratios for patients who drank < or = 75 g and > 75 g of ethanol a week compared with non-drinkers were 0.90 (95% confidence interval 0.55 to 1.59) and 0.33 (0.16 to 0.68), respectively (P value for trend 0.005, assuming that 1 litre of beer and 0.51 of wine contain on average 50 g of ethanol in south Germany). Adjusted odds ratios for patients who drank < 3 cups and > or = 3 cups of coffee per day compared with those who did not drink coffee were 1.49 (0.71 to 3.12) and 2.49 (1.23 to 5.03), respectively (P value for trend 0.007). CONCLUSION: These results suggest a protective effect of alcohol consumption against active infection with H pylori and an opposite effect of coffee consumption. PMID:9420488

  18. Perceptions of Health-Related Information on Facebook: Cross-Sectional Study Among Vietnamese Youths.

    PubMed

    Zhang, Melvyn Wb; Tran, Bach Xuan; Le, Huong Thi; Nguyen, Hinh Duc; Nguyen, Cuong Tat; Tran, Tho Dinh; Latkin, Carl A; Ho, Roger Cm

    2017-09-07

    While health information websites may have previously been the core source of information about health-related conditions on the Internet, social networking sites are increasingly replacing those websites as a source of health-related information. The increasingly popularity of social networking sites among the general population has consequential impact on health policies as well as health-related interventions. To date, there remains a paucity of research conducted in developing countries like Vietnam looking at the influence of social networking sites. Our goal is to establish the baseline use of Facebook among Vietnamese youths and establish their perception of the reliability and usefulness of health-related information that they previously encountered while using the social networking site. An online cross-sectional study was conducted from August 2015 to October 2015. Respondent-driven sampling (RDS) technique was used in the recruitment of participants. Sociodemographic, health status, behaviors, Facebook use and belief of information on Facebook, and interpersonal influence of social network sites were collected via an online structured questionnaire. Among 1080 participants, 72.87% (787/1080) reported being interested in health information on Facebook, and 50.74% (548/1080) and 17.50% (189/1080) perceived the information to be reliable and useful, respectively. A total of 10.93% (118/1080) of the participants also reported that they would follow the health advice they obtained from Facebook. Of significance, 7.13% (77/1080) of the participants also reported peer influences on their behavior. Factors that mediate Vietnamese perceptions of the information online include gender, level of perceived stress, age, educational level, and interpersonal influences from Facebook. Our study is perhaps one of the first conducted in Vietnam that looks at the relationship between health information on Facebook and factors that might influence young Vietnamese

  19. Prevalence of factors related to active reproductive health behavior: a cross-sectional study Indonesian adolescent

    PubMed Central

    Kimura, Rumiko; Tsuda, Akiko; Tabuchi, Noriko

    2016-01-01

    OBJECTIVES Complex and diverse factors are related to reproductive health (RH) behavior among adolescents according to the social and cultural context of each countries. This study examined the prevalence of active RH and factors related to active RH behavior among Indonesian adolescents. METHODS A cross-sectional study was conducted among 1,040 of students who were selected through a multi-stage random sampling technique. A self-administered questionnaire was developed, including the World Health Organization Illustrative Questionnaire for Interview-Surveys with Young People, pubertal development scale, and sexual activity scale, modified in accordance to the Indonesian context. The data were analyzed using descriptive and comparative statistics, as well as logistic regression analyses. RESULTS The prevalence of active RH behavior were more higher in boys (56.6%; 95% confidence interval [CI], 50.6% to 62.6%) than in girls (43.7%; 95% CI, 37.6% to 49.8%). Negative attitudes towards RH were a factor related to active RH behavior in both boys and girls. Smoking and kind relationship envisioned before marriage (pacaran [courtship] and nikah siri [non-registered marriage]) were factors related to active RH behavior in boys; whereas the absence of access to information on substance abuse was an additional factor in girls. Moreover, an interaction was found between access to information on development and smoking (boys) and attitudes on RH (girls) as independent variables associated with active RH behavior. CONCLUSIONS Sex education for adolescents in Indonesia, particularly in the context of a health promotion program, should be developed based on prevalent social, cultural, and religious values to prevent active RH behavior. Such programs should focus on the kind of relationship envisioned before marriage and smoking for boys and access to information on subtance abuse for girls. PMID:27866406

  20. Prevalence of factors related to active reproductive health behavior: a cross-sectional study Indonesian adolescent.

    PubMed

    Susanto, Tantut; Rahmawati, Iis; Wuryaningsih, Emi Wuri; Saito, Ruka; Syahrul; Kimura, Rumiko; Tsuda, Akiko; Tabuchi, Noriko; Sugama, Junko

    2016-01-01

    Complex and diverse factors are related to reproductive health (RH) behavior among adolescents according to the social and cultural context of each countries. This study examined the prevalence of active RH and factors related to active RH behavior among Indonesian adolescents. A cross-sectional study was conducted among 1,040 of students who were selected through a multi-stage random sampling technique. A self-administered questionnaire was developed, including the World Health Organization Illustrative Questionnaire for Interview-Surveys with Young People, pubertal development scale, and sexual activity scale, modified in accordance to the Indonesian context. The data were analyzed using descriptive and comparative statistics, as well as logistic regression analyses. The prevalence of active RH behavior were more higher in boys (56.6%; 95% confidence interval [CI], 50.6% to 62.6%) than in girls (43.7%; 95% CI, 37.6% to 49.8%). Negative attitudes towards RH were a factor related to active RH behavior in both boys and girls. Smoking and kind relationship envisioned before marriage (pacaran [courtship] and nikah siri [non-registered marriage]) were factors related to active RH behavior in boys; whereas the absence of access to information on substance abuse was an additional factor in girls. Moreover, an interaction was found between access to information on development and smoking (boys) and attitudes on RH (girls) as independent variables associated with active RH behavior. Sex education for adolescents in Indonesia, particularly in the context of a health promotion program, should be developed based on prevalent social, cultural, and religious values to prevent active RH behavior. Such programs should focus on the kind of relationship envisioned before marriage and smoking for boys and access to information on subtance abuse for girls.