WorldWideScience

Sample records for surface variability extends

  1. ESA STSE Project “Sea Surface Temperature Diurnal Variability: Regional Extend – Implications in Atmospheric Modelling”

    DEFF Research Database (Denmark)

    Karagali, Ioanna

    of the vertical extend of diurnal signals. Drifting buoys provide measurements close to the surface but are not always available. Moored buoys are generally not able to resolve the daily SST signal, which strongly weakens with depth within the upper water column. For such reasons, the General Ocean Turbulence......, atmospheric and oceanic modelling, bio-chemical processes and oceanic CO2 studies. The diurnal variability of SST, driven by the coincident occurrence of low enough wind and solar heating, is currently not properly understood. Atmospheric, oceanic and climate models are currently not adequately resolving...... the daily SST variability, resulting in biases of the total heat budget estimates and therefore, demised model accuracies. The ESA STSE funded project SSTDV:R.EX.-IM.A.M. aimed at characterising the regional extend of diurnal SST signals and their impact in atmospheric modelling. This study will briefly...

  2. Steady nanofluid flow with variable fluid possessions over a linearly extending surface: A Lie group exploration

    Directory of Open Access Journals (Sweden)

    Kalidas Das

    2018-03-01

    Full Text Available The temperament of stream characteristic, heat and mass transfer of MHD forced convective flow over a linearly expanding porous medium has been scrutinized in the progress exploration. The germane possessions of the liquid like viscosity along with thermal conductivity are believed to be variable in nature, directly influenced by the temperature of flow. As soon as gaining the system of leading equations of the stream, Lie symmetric group transformations have been employed to come across the fitting parallel conversions to alter the central PDEs into a suit of ODEs. The renovated system of ODE with appropriate boundary conditions is numerically solved with the assistance of illustrative software MAPLE 17. The consequences of the relevant factors of the system have been exemplified through charts and graphs. An analogous qualified survey has been prepared among present inquiry and subsisting reads and achieved an admirable accord between them. The variable viscosity parameter has more significant effect on nanofluid velocity than regular fluid and temporal profile as well as nanoparticle concentration is also influenced with variable viscosity. Keywords: Nanofluid, Stretching sheet, Variable viscosity, Variable thermal conductivity, Lie symmetry group

  3. Internal variability of fine-scale components of meteorological fields in extended-range limited-area model simulations with atmospheric and surface nudging

    Science.gov (United States)

    Separovic, Leo; Husain, Syed Zahid; Yu, Wei

    2015-09-01

    Internal variability (IV) in dynamical downscaling with limited-area models (LAMs) represents a source of error inherent to the downscaled fields, which originates from the sensitive dependence of the models to arbitrarily small modifications. If IV is large it may impose the need for probabilistic verification of the downscaled information. Atmospheric spectral nudging (ASN) can reduce IV in LAMs as it constrains the large-scale components of LAM fields in the interior of the computational domain and thus prevents any considerable penetration of sensitively dependent deviations into the range of large scales. Using initial condition ensembles, the present study quantifies the impact of ASN on IV in LAM simulations in the range of fine scales that are not controlled by spectral nudging. Four simulation configurations that all include strong ASN but differ in the nudging settings are considered. In the fifth configuration, grid nudging of land surface variables toward high-resolution surface analyses is applied. The results show that the IV at scales larger than 300 km can be suppressed by selecting an appropriate ASN setup. At scales between 300 and 30 km, however, in all configurations, the hourly near-surface temperature, humidity, and winds are only partly reproducible. Nudging the land surface variables is found to have the potential to significantly reduce IV, particularly for fine-scale temperature and humidity. On the other hand, hourly precipitation accumulations at these scales are generally irreproducible in all configurations, and probabilistic approach to downscaling is therefore recommended.

  4. Extended Reconstructed Sea Surface Temperature (ERSST)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature analysis derived from the International Comprehensive...

  5. Extended Lagrangian formalism for rheonomic systems with variable mass

    Directory of Open Access Journals (Sweden)

    Mušicki Đorđe

    2017-01-01

    Full Text Available In this paper the extended Lagrangian formalism for the rheonomic systems (Dj. Mušicki, 2004, which began with the modification of the mechanics of such systems (V. Vujičić, 1987, is extended to the systems with variable mass, with emphasis on the corresponding energy relations. This extended Lagrangian formalism is based on the extension of the set of chosen generalized coordinates by new quantities, suggested by the form of nonstationary constraints, which determine the position of the frame of reference in respect to which these generalized coordinates refer. As a consequence, an extended system of the Lagrangian equations is formulated, accommodated to the variability of the masses of particles, where the additional ones correspond to the additional generalized coordinates. By means of these equations, the energy relations of such systems have been studied, where it is demonstrated that here there are four types of energy conservation laws. The obtained energy laws are more complete and natural than the corresponding ones in the usual Lagrangian formulation for such systems. It is demonstrated that the obtained energy laws, are in full accordance with the energy laws in the corresponding vector formulation, if they are expressed in terms of the quantities introduced in this formulation of mechanics. The obtained results are illustrated by an example: the motion of a rocket, which ejects the gasses backwards, while this rocket moves up a straight line on an oblique plane, which glides uniformly in a horizontal direction.

  6. Extended KN algebras and extended conformal field theories over higher genus Riemann surfaces

    International Nuclear Information System (INIS)

    Ceresole, A.; Huang Chaoshang

    1990-01-01

    A global operator formalism for extended conformal field theories over higher genus Riemann surfaces is introduced and extended KN algebra are obtained by means of the KN bases. The BBSS construction of the spin-3 operator is carried out for Kac-Moody algebra A 2 over a Riemann surface of arbitrary genus. (orig.)

  7. NOAA Extended Reconstructed Sea Surface Temperature (ERSST), Version 5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature dataset derived from the International...

  8. Extended Reconstructed Sea Surface Temperature (ERSST), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature analysis on a 2x2 degree grid derived from the...

  9. An extended rational thermodynamics model for surface excess fluxes

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2012-01-01

    In this paper, we derive constitutive equations for the surface excess fluxes in multiphase systems, in the context of an extended rational thermodynamics formalism. This formalism allows us to derive Maxwell–Cattaneo type constitutive laws for the surface extra stress tensor, the surface thermal

  10. In-Situ Extended Lateral Range Surface Metrology, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an extended lateral range capability for a dynamic optical profiling system to enable non-contact, surface roughness measurement of large and...

  11. Experimental and numerical analyses of different extended surfaces

    International Nuclear Information System (INIS)

    Diani, A; Mancin, S; Zilio, C; Rossetto, L

    2012-01-01

    Air is a cheap and safe fluid, widely used in electronic, aerospace and air conditioning applications. Because of its poor heat transfer properties, it always flows through extended surfaces, such as finned surfaces, to enhance the convective heat transfer. In this paper, experimental results are reviewed and numerical studies during air forced convection through extended surfaces are presented. The thermal and hydraulic behaviours of a reference trapezoidal finned surface, experimentally evaluated by present authors in an open-circuit wind tunnel, has been compared with numerical simulations carried out by using the commercial CFD software COMSOL Multiphysics. Once the model has been validated, numerical simulations have been extended to other rectangular finned configurations, in order to study the effects of the fin thickness, fin pitch and fin height on the thermo-hydraulic behaviour of the extended surfaces. Moreover, several pin fin surfaces have been simulated in the same range of operating conditions previously analyzed. Numerical results about heat transfer and pressure drop, for both plain finned and pin fin surfaces, have been compared with empirical correlations from the open literature, and more accurate equations have been developed, proposed, and validated.

  12. High-resolution surface analysis for extended-range downscaling with limited-area atmospheric models

    Science.gov (United States)

    Separovic, Leo; Husain, Syed Zahid; Yu, Wei; Fernig, David

    2014-12-01

    High-resolution limited-area model (LAM) simulations are frequently employed to downscale coarse-resolution objective analyses over a specified area of the globe using high-resolution computational grids. When LAMs are integrated over extended time frames, from months to years, they are prone to deviations in land surface variables that can be harmful to the quality of the simulated near-surface fields. Nudging of the prognostic surface fields toward a reference-gridded data set is therefore devised in order to prevent the atmospheric model from diverging from the expected values. This paper presents a method to generate high-resolution analyses of land-surface variables, such as surface canopy temperature, soil moisture, and snow conditions, to be used for the relaxation of lower boundary conditions in extended-range LAM simulations. The proposed method is based on performing offline simulations with an external surface model, forced with the near-surface meteorological fields derived from short-range forecast, operational analyses, and observed temperatures and humidity. Results show that the outputs of the surface model obtained in the present study have potential to improve the near-surface atmospheric fields in extended-range LAM integrations.

  13. Scaled multisensor inspection of extended surfaces for industrial quality control

    Science.gov (United States)

    Kayser, Daniel; Bothe, Thorsten; Osten, Wolfgang

    2002-06-01

    Reliable real-time surface inspection of extended surfaces with high resolution is needed in several industrial applications. With respect to an efficient application to extended technical components such as aircraft or automotive parts, the inspection system has to perform a robust measurement with a ratio of less then 10-6 between depth resolution and lateral extension. This ratio is at least one order beyond the solutions that are offered by existing technologies. The concept of scaled topometry consists of arranging different optical measurement techniques with overlapping ranges of resolution systematically in order to receive characteristic surface information with the required accuracy. In such a surface inspection system, an active algorithm combines measurements on several scales of resolution and distinguishes between local fault indicating structures with different extensions and global geometric properties. The first part of this active algorithm finds indications of critical surface areas in the data of every measurement and separates them into different categories. The second part analyses the detected structures in the data with respect to their resolution and decides whether a further local measurement with a higher resolution has to be performed. The third part positions the sensors and starts the refined measurements. The fourth part finally integrates the measured local data set into the overall data mesh. We have constructed a laboratory setup capable of measuring surfaces with extensions up to 1500mm x 1000mm x 500mm (in x-, y- and z-direction respectively). Using this measurement system we will be able to separate the fault indicating structures on the surface from the global shape and to classify the detected structures according to their extensions and characteristic shapes simultaneously. The level of fault detection probability will be applicable by input parameter control.

  14. Equivalent conditions of complete moment convergence for extended negatively dependent random variables

    Directory of Open Access Journals (Sweden)

    Qunying Wu

    2017-05-01

    Full Text Available Abstract In this paper, we study the equivalent conditions of complete moment convergence for sequences of identically distributed extended negatively dependent random variables. As a result, we extend and generalize some results of complete moment convergence obtained by Chow (Bull. Inst. Math. Acad. Sin. 16:177-201, 1988 and Li and Spătaru (J. Theor. Probab. 18:933-947, 2005 from the i.i.d. case to extended negatively dependent sequences.

  15. Water entry without surface seal: Extended cavity formation

    KAUST Repository

    Mansoor, Mohammad M.

    2014-03-01

    We report results from an experimental study of cavity formation during the impact of superhydrophobic spheres onto water. Using a simple splash-guard mechanism, we block the spray emerging during initial contact from closing thus eliminating the phenomenon known as \\'surface seal\\', which typically occurs at Froude numbers Fr= V0 2/(gR0) = O(100). As such, we are able to observe the evolution of a smooth cavity in a more extended parameter space than has been achieved in previous studies. Furthermore, by systematically varying the tank size and sphere diameter, we examine the influence of increasing wall effects on these guarded impact cavities and note the formation of surface undulations with wavelength λ =O(10)cm and acoustic waves λa=O(D0) along the cavity interface, which produce multiple pinch-off points. Acoustic waves are initiated by pressure perturbations, which themselves are generated by the primary cavity pinch-off. Using high-speed particle image velocimetry (PIV) techniques we study the bulk fluid flow for the most constrained geometry and show the larger undulations ( λ =O (10cm)) have a fixed nature with respect to the lab frame. We show that previously deduced scalings for the normalized (primary) pinch-off location (ratio of pinch-off depth to sphere depth at pinch-off time), Hp/H = 1/2, and pinch-off time, τ α (R0/g) 1/2, do not hold for these extended cavities in the presence of strong wall effects (sphere-to-tank diameter ratio), ε = D 0/Dtank 1/16. Instead, we find multiple distinct regimes for values of Hp/H as the observed undulations are induced above the first pinch-off point as the impact speed increases. We also report observations of \\'kinked\\' pinch-off points and the suppression of downward facing jets in the presence of wall effects. Surprisingly, upward facing jets emanating from first cavity pinch-off points evolve into a \\'flat\\' structure at high impact speeds, both in the presence and absence of wall effects.

  16. An Extended TOPSIS Method for Multiple Attribute Decision Making based on Interval Neutrosophic Uncertain Linguistic Variables

    Directory of Open Access Journals (Sweden)

    Said Broumi

    2015-03-01

    Full Text Available The interval neutrosophic uncertain linguistic variables can easily express the indeterminate and inconsistent information in real world, and TOPSIS is a very effective decision making method more and more extensive applications. In this paper, we will extend the TOPSIS method to deal with the interval neutrosophic uncertain linguistic information, and propose an extended TOPSIS method to solve the multiple attribute decision making problems in which the attribute value takes the form of the interval neutrosophic uncertain linguistic variables and attribute weight is unknown. Firstly, the operational rules and properties for the interval neutrosophic variables are introduced. Then the distance between two interval neutrosophic uncertain linguistic variables is proposed and the attribute weight is calculated by the maximizing deviation method, and the closeness coefficients to the ideal solution for each alternatives. Finally, an illustrative example is given to illustrate the decision making steps and the effectiveness of the proposed method.

  17. Seasonal Climatologies and Variability of Eastern Tropical Pacific Surface Waters

    OpenAIRE

    Fiedler, Paul C.

    1992-01-01

    Interannual variability caused by the El Nino-Southern Oscillation in the eastern tropical Pacific Ocean (ETP) is analogous to seasonal variability of comparable magnitude. Climatological spatial patterns and seasonal variability of physical variables that may affect the ETP ecosystem are presented and discussed. Surface temperature, surface salinity, mixed layer depth, thermocline depth, thermocline strength, and surface dynamic height were derived from bathythermograph, hydrocast, and...

  18. Panel data models extended to spatial error autocorrelation or a spatially lagged dependent variable

    NARCIS (Netherlands)

    Elhorst, J. Paul

    2001-01-01

    This paper surveys panel data models extended to spatial error autocorrelation or a spatially lagged dependent variable. In particular, it focuses on the specification and estimation of four panel data models commonly used in applied research: the fixed effects model, the random effects model, the

  19. SURFACE ALBEDO AND SPECTRAL VARIABILITY OF CERES

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian-Yang; Reddy, Vishnu; Corre, Lucille Le; Sykes, Mark V.; Prettyman, Thomas H. [Planetary Science Institute, 1700 E. Ft. Lowell Road, Suite 106, Tucson, AZ 85719 (United States); Nathues, Andreas; Hoffmann, Martin; Schaefer, Michael [Max Planck Institute for Solar System Research, Göttingen (Germany); Izawa, Matthew R. M.; Cloutis, Edward A. [University of Winnipeg, Winnipeg, Manitoba (Canada); Carsenty, Uri; Jaumann, Ralf; Krohn, Katrin; Mottola, Stefano; Schröder, Stefan E. [German Aerospace Center (DLR), Institute of Planetary Research, Berlin (Germany); Castillo-Rogez, Julie C. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Schenk, Paul [Lunar and Planetary Institute, Houston, TX 77058 (United States); Williams, David A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Smith, David E. [Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Zuber, Maria T. [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); and others

    2016-02-01

    Previous observations suggested that Ceres has active, but possibly sporadic, water outgassing as well as possibly varying spectral characteristics over a timescale of months. We used all available data of Ceres collected in the past three decades from the ground and the Hubble Space Telescope, as well as the newly acquired images by the Dawn  Framing Camera, to search for spectral and albedo variability on Ceres, on both a global scale and in local regions, particularly the bright spots inside the Occator crater, over timescales of a few months to decades. Our analysis has placed an upper limit on the possible temporal albedo variation on Ceres. Sporadic water vapor venting, or any possibly ongoing activity on Ceres, is not significant enough to change the albedo or the area of the bright features in the Occator crater by >15%, or the global albedo by >3% over the various timescales that we searched. Recently reported spectral slope variations can be explained by changing Sun–Ceres–Earth geometry. The active area on Ceres is less than 1 km{sup 2}, too small to cause global albedo and spectral variations detectable in our data. Impact ejecta due to impacting projectiles of tens of meters in size like those known to cause observable changes to the surface albedo on Asteroid Scheila cannot cause detectable albedo change on Ceres due to its relatively large size and strong gravity. The water vapor activity on Ceres is independent of Ceres’ heliocentric distance, ruling out the possibility of the comet-like sublimation process as a possible mechanism driving the activity.

  20. Heat transfer effect of an extended surface in downward-facing subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Abdul R., E-mail: khan@vis.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Erkan, Nejdet, E-mail: erkan@vis.t.u-tokyo.ac.jp [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki, 319-1188 (Japan); Okamoto, Koji, E-mail: okamoto@n.t.u-tokyo.ac.jp [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki, 319-1188 (Japan)

    2015-12-15

    Highlights: • Compare downward-facing flow boiling results from bare and extended surfaces. • Upstream and downstream temperatures were measured on the extended surface. • Downstream temperatures exceed upstream temperatures for all flow rates. • Bubble accumulation occurs downstream on extended surface. • Extended surface heat transfer lower than bare surface as flow rate reduced. - Abstract: New BWR containment designs are considering cavity flooding as an accident management strategy. Unlike the PWR, the BWR has many Control Rod Guide Tube (CRGT) penetrations in the lower head. During a severe accident scenario with core melt in the lower plenum along with cavity flooding, the penetrations may affect the heat transfer on the ex-vessel surface and disrupt fluid flow during the boiling process. A small-scale experiment was performed to investigate the issues existing in downward-facing boiling phenomenon with an extended surface. The results were compared with a bare (flat) surface. The mass flux of 244 kg/m{sup 2} s, 215 kg/m{sup 2} s, and 177 kg/m{sup 2} s were applied in this study. CHF conditions were observed only for the 177 kg/m{sup 2} s case. The boiling curves for both types of surfaces and all flow rates were obtained. The boiling curves for the highest flow rate showed lower surface temperatures for the extended surface experiments when compared to the bare surface. The downstream location on the extended surface yielded the highest surface temperatures as the flow rate was reduced. The bubble accumulation and low velocity in the wake produced by flow around the extended surface was believed to have caused the elevated temperatures in the downstream location. Although an extended surface may enhance the overall heat transfer, a reduction in the local heat transfer was observed in the current experiments.

  1. On the predictability of land surface fluxes from meteorological variables

    Science.gov (United States)

    Haughton, Ned; Abramowitz, Gab; Pitman, Andy J.

    2018-01-01

    Previous research has shown that land surface models (LSMs) are performing poorly when compared with relatively simple empirical models over a wide range of metrics and environments. Atmospheric driving data appear to provide information about land surface fluxes that LSMs are not fully utilising. Here, we further quantify the information available in the meteorological forcing data that are used by LSMs for predicting land surface fluxes, by interrogating FLUXNET data, and extending the benchmarking methodology used in previous experiments. We show that substantial performance improvement is possible for empirical models using meteorological data alone, with no explicit vegetation or soil properties, thus setting lower bounds on a priori expectations on LSM performance. The process also identifies key meteorological variables that provide predictive power. We provide an ensemble of empirical benchmarks that are simple to reproduce and provide a range of behaviours and predictive performance, acting as a baseline benchmark set for future studies. We reanalyse previously published LSM simulations and show that there is more diversity between LSMs than previously indicated, although it remains unclear why LSMs are broadly performing so much worse than simple empirical models.

  2. Iterative Strain-Gage Balance Calibration Data Analysis for Extended Independent Variable Sets

    Science.gov (United States)

    Ulbrich, Norbert Manfred

    2011-01-01

    A new method was developed that makes it possible to use an extended set of independent calibration variables for an iterative analysis of wind tunnel strain gage balance calibration data. The new method permits the application of the iterative analysis method whenever the total number of balance loads and other independent calibration variables is greater than the total number of measured strain gage outputs. Iteration equations used by the iterative analysis method have the limitation that the number of independent and dependent variables must match. The new method circumvents this limitation. It simply adds a missing dependent variable to the original data set by using an additional independent variable also as an additional dependent variable. Then, the desired solution of the regression analysis problem can be obtained that fits each gage output as a function of both the original and additional independent calibration variables. The final regression coefficients can be converted to data reduction matrix coefficients because the missing dependent variables were added to the data set without changing the regression analysis result for each gage output. Therefore, the new method still supports the application of the two load iteration equation choices that the iterative method traditionally uses for the prediction of balance loads during a wind tunnel test. An example is discussed in the paper that illustrates the application of the new method to a realistic simulation of temperature dependent calibration data set of a six component balance.

  3. Frequency Selective Surfaces for extended Bandwidth backing reflector functions

    NARCIS (Netherlands)

    Pasian, M.; Neto, A.; Monni, S.; Ettorre, M.; Gerini, G.

    2008-01-01

    This paper deals with the use of Frequency Selective Surfaces (FSS) to increase the Efficiency × Bandwidth product in Ultra-Wide Band (UWB) antenna arrays whose efficiency is limited by the front-to-back ratio. If the backing reflector is realized in one metal plane solution its location will be

  4. Extended q -Gaussian and q -exponential distributions from gamma random variables

    Science.gov (United States)

    Budini, Adrián A.

    2015-05-01

    The family of q -Gaussian and q -exponential probability densities fit the statistical behavior of diverse complex self-similar nonequilibrium systems. These distributions, independently of the underlying dynamics, can rigorously be obtained by maximizing Tsallis "nonextensive" entropy under appropriate constraints, as well as from superstatistical models. In this paper we provide an alternative and complementary scheme for deriving these objects. We show that q -Gaussian and q -exponential random variables can always be expressed as a function of two statistically independent gamma random variables with the same scale parameter. Their shape index determines the complexity q parameter. This result also allows us to define an extended family of asymmetric q -Gaussian and modified q -exponential densities, which reduce to the standard ones when the shape parameters are the same. Furthermore, we demonstrate that a simple change of variables always allows relating any of these distributions with a beta stochastic variable. The extended distributions are applied in the statistical description of different complex dynamics such as log-return signals in financial markets and motion of point defects in a fluid flow.

  5. Impact of including surface currents on simulation of Indian Ocean variability with the POAMA coupled model

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Mei; Wang, Guomin; Hendon, Harry H.; Alves, Oscar [Bureau of Meteorology, Centre for Australian Weather and Climate Research, Melbourne (Australia)

    2011-04-15

    Impacts on the coupled variability of the Indo-Pacific by including the effects of surface currents on surface stress are explored in four extended integrations of an experimental version of the Bureau of Meteorology's coupled seasonal forecast model POAMA. The first pair of simulations differs only in their treatment of momentum coupling: one version includes the effects of surface currents on the surface stress computation and the other does not. The version that includes the effect of surface currents has less mean-state bias in the equatorial Pacific cold tongue but produces relatively weak coupled variability in the Tropics, especially that related to the Indian Ocean dipole (IOD) and El Nino/Southern Oscillation (ENSO). The version without the effects of surface currents has greater bias in the Pacific cold tongue but stronger IOD and ENSO variability. In order to diagnose the role of changes in local coupling from changes in remote forcing by ENSO for causing changes in IOD variability, a second set of simulations is conducted where effects of surface currents are included only in the Indian Ocean and only in the Pacific Ocean. IOD variability is found to be equally reduced by inclusion of the local effects of surface currents in the Indian Ocean and by the reduction of ENSO variability as a result of including effects of surface currents in the Pacific. Some implications of these results for predictability of the IOD and its dependence on ENSO, and for ocean subsurface data assimilation are discussed. (orig.)

  6. Roughness Length Variability over Heterogeneous Surfaces

    Science.gov (United States)

    2010-03-01

    2004), the influence of variable roughness reaches its maximum at the height of local 0z and vanishes at the so- called blending height (Wieringa...the distribution of visibility restrictors such as low clouds, fog, haze, dust, and pollutants . An improved understanding of ABL structure...R. D., B. H. Lynn, A. Boone, W.-K. Tao, and J. Simpson, 2001: The influence of soil moisture, coastline curvature, and land-breeze circulations on

  7. Natural variability in the surface ocean carbonate ion concentration

    OpenAIRE

    N. S. Lovenduski; M. C. Long; K. Lindsay

    2015-01-01

    We investigate variability in the surface ocean carbonate ion concentration ([CO32−]) on the basis of a long control simulation with a fully-coupled Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical...

  8. Natural variability in the surface ocean carbonate ion concentration

    OpenAIRE

    Lovenduski, N. S.; Long, M. C.; Lindsay, K.

    2015-01-01

    We investigate variability in the surface ocean carbonate ion concentration ([CO32−]) on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and ...

  9. Extended Reconstructed Sea Surface Temperature (ERSST) Monthly Analysis, Version 3b

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Version 3b (v3b) of the Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a monthly SST analysis on a 2-degree global grid based on the International...

  10. Global control of reaction wheel pendulum through energy regulation and extended linearization of the state variables

    Directory of Open Access Journals (Sweden)

    Oscar D. Montoya-Giraldo

    2014-01-01

    Full Text Available This paper presents the design and simulation of a global controller for the Reaction Wheel Pendulum system using energy regulation and extended linearization methods for the state feedback. The proposed energy regulation is based on the gradual reduction of the energy of the system to reach the unstable equilibrium point. The signal input for this task is obtained from the Lyapunov stability theory. The extended state feedback controller design is used to get a smooth nonlinear function that extends the region of operation to a bigger range, in contrast with the static linear state feedback obtained through the method of approximate linearization around an operating point. The general designed controller operates with a switching between the two control signals depending upon the region of operation; perturbations are applied in the control signal and the (simulated measured variables to verify the robustness and efficiency of the controller. Finally, simulations and tests using the model of the reaction wheel pendulum system, allow to observe the versatility and functionality of the proposed controller in the entire operation region of the pendulum.

  11. The hydrophobic effect: Molecular dynamics simulations of water confined between extended hydrophobic and hydrophilic surfaces

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Mouritsen, Ole G.; Peters, Günther H.J.

    2004-01-01

    Structural and dynamic properties of water confined between two parallel, extended, either hydrophobic or hydrophilic crystalline surfaces of n-alkane C36H74 or n-alcohol C35H71OH, are studied by molecular dynamics simulations. Electron density profiles, directly compared with corresponding......-correlation functions reveal that water molecules have characteristic diffusive behavior and orientational ordering due to the lack of hydrogen bonding interactions with the surface. These observations suggest that the altered dynamical properties of water in contact with extended hydrophobic surfaces together...... at both surfaces. The ordering is characteristically different between the surfaces and of longer range at the hydrophilic surface. Furthermore, the dynamic properties of water are different at the two surfaces and different from the bulk behavior. In particular, at the hydrophobic surface, time...

  12. Assimilation of lake water surface temperature observations using an extended Kalman filter

    Directory of Open Access Journals (Sweden)

    Ekaterina Kourzeneva

    2014-10-01

    Full Text Available A new extended Kalman filter (EKF-based algorithm to assimilate lake water surface temperature (LWST observations into the lake model/parameterisation scheme Freshwater Lake (FLake has been developed. The data assimilation algorithm has been implemented into the stand-alone offline version of FLake. The mixed and non-mixed regimes in lakes are treated separately by the EKF algorithm. The timing of the ice period is indicated implicitly: no ice if water surface temperature is measured. Numerical experiments are performed using operational in-situ observations for 27 lakes and merged observations (in-situ plus satellite for 4 lakes in Finland. Experiments are analysed, potential problems are discussed, and the role of early spring observations is studied. In general, results of experiments are promising: (1 the impact of observations (calculated as the normalised reduction of the LWST root mean square error comparing to the free model run is more than 90% and (2 in cross-validation (when observations are partly assimilated, partly used for validation the normalised reduction of the LWST error standard deviation is more than 65%. The new data assimilation algorithm will allow prognostic variables in the lake parameterisation scheme to be initialised in operational numerical weather prediction models and the effects of model errors to be corrected by using LWST observations.

  13. Interannual variability of sea surface temperature and circulation in ...

    African Journals Online (AJOL)

    Local surface heat flux exchanges driven by the anomalous shortwave radiation dominated the interannual SST variability in the Tanzanian shelf region, with some contribution by the advection of heat anomalies from the North-East Madagascar Current. Farther offshore, the interannual variability of the SST was dominated ...

  14. Improvement of the variable storage coefficient method with water surface gradient as a variable

    Science.gov (United States)

    The variable storage coefficient (VSC) method has been used for streamflow routing in continuous hydrological simulation models such as the Agricultural Policy/Environmental eXtender (APEX) and the Soil and Water Assessment Tool (SWAT) for more than 30 years. APEX operates on a daily time step and ...

  15. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-11-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30-year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results

  16. Natural variability in the surface ocean carbonate ion concentration

    Science.gov (United States)

    Lovenduski, N. S.; Long, M. C.; Lindsay, K.

    2015-11-01

    We investigate variability in the surface ocean carbonate ion concentration ([CO32-]) on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32-] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32-] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32-] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite) are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32-] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC) in association with El Niño-Southern Oscillation. In the North Pacific, surface [CO32-] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20-30-year periods. North Atlantic [CO32-] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results will aid the interpretation of trends

  17. Identification of faint central stars in extended, low-surface-brightness planetary nebulae

    International Nuclear Information System (INIS)

    Kwitter, K.B.; Lydon, T.J.; Jacoby, G.H.

    1988-01-01

    As part of a larger program to study the properties of planetary nebula central stars, a search for faint central stars in extended, low-surface-brightness planetary nebulae using CCD imaging is performed. Of 25 target nebulae, central star candidates have been identified in 17, with certainties ranging from extremely probable to possible. Observed V values in the central star candidates extend to fainter than 23 mag. The identifications are presented along with the resulting photometric measurements. 24 references

  18. Extended Reconstructed Sea Surface Temperature Version 5 (ERSSTv5): Upgrades, Validations, and Intercomparisons

    Science.gov (United States)

    Huang, B.; Thorne, P.; Banzon, P. V. F.; Chepurin, G. A.; Lawrimore, J. H.; Menne, M. J.; Vose, R. S.; Smith, T. M.; Zhang, H. M.

    2017-12-01

    The monthly global 2°×2° Extended Reconstructed Sea Surface Temperature (ERSST) has been revised and updated from version 4 to version 5. This update incorporates a new release of ICOADS R3.0, a decade of near-surface data from Argo floats, and a new estimate of centennial sea-ice from HadISST2. A number of choices in aspects of quality control, bias adjustment and interpolation have been substantively revised. The resulting ERSST estimates have more realistic spatio-temporal variations, better representation of high latitude SSTs, and ship SST biases are now calculated relative to more accurate buoy measurements, while the global long-term trend remains about the same. Progressive experiments have been undertaken to highlight the effects of each change in data source and analysis technique upon the final product. The reconstructed SST is systematically decreased by 0.077°C, as the reference data source is switched from ship SST in v4 to modern buoy SST in v5. Furthermore, high latitude SSTs are decreased by 0.1°-0.2°C by using sea-ice concentration from HadISST2 over HadISST1. Changes arising from remaining innovations are mostly important at small space and time scales, primarily having an impact where and when input observations are sparse. Cross-validations and verifications with independent modern observations show that the updates incorporated in ERSSTv5 have improved the representation of spatial variability over the global oceans, the magnitude of El Niño and La Niña events, and the decadal nature of SST changes over 1930s-40s when observation instruments changed rapidly. Both long (1900-2015) and short (2000-2015) term SST trends in ERSSTv5 remain significant as in ERSSTv4.

  19. Intercomparison of the Extended Reconstructed Sea Surface Temperature v4 and v3b Datasets

    Science.gov (United States)

    Wang, Jinping; Chen, Xianyao

    2018-04-01

    Version 4 (v4) of the Extended Reconstructed Sea Surface Temperature (ERSST) dataset is compared with its precedent, the widely used version 3b (v3b). The essential upgrades applied to v4 lead to remarkable differences in the characteristics of the sea surface temperature (SST) anomaly (SSTa) in both the temporal and spatial domains. First, the largest discrepancy of the global mean SSTa values around the 1940s is due to ship-observation corrections made to reconcile observations from buckets and engine intake thermometers. Second, differences in global and regional mean SSTa values between v4 and v3b exhibit a downward trend (around -0.032°C per decade) before the 1940s, an upward trend (around 0.014°C per decade) during the period of 1950-2015, interdecadal oscillation with one peak around the 1980s, and two troughs during the 1960s and 2000s, respectively. This does not derive from treatments of the polar or the other data-void regions, since the difference of the SSTa does not share the common features. Third, the spatial pattern of the ENSO-related variability of v4 exhibits a wider but weaker cold tongue in the tropical region of the Pacific Ocean compared with that of v3b, which could be attributed to differences in gap-filling assumptions since the latter features satellite observations whereas the former features in situ ones. This intercomparison confirms that the structural uncertainty arising from underlying assumptions on the treatment of diverse SST observations even in the same SST product family is the main source of significant SST differences in the temporal domain. Why this uncertainty introduces artificial decadal oscillations remains unknown.

  20. Variable separation solutions for the Nizhnik-Novikov-Veselov equation via the extended tanh-function method

    International Nuclear Information System (INIS)

    Zhang Jiefang; Dai Chaoqing; Zong Fengde

    2007-01-01

    In this paper, with the variable separation approach and based on the general reduction theory, we successfully generalize this extended tanh-function method to obtain new types of variable separation solutions for the following Nizhnik-Novikov-Veselov (NNV) equation. Among the solutions, two solutions are new types of variable separation solutions, while the last solution is similar to the solution given by Darboux transformation in Hu et al 2003 Chin. Phys. Lett. 20 1413

  1. Intraseasonal sea surface temperature variability in Indonesian seas

    Science.gov (United States)

    Napitu, A. M.; Gordon, A. L.; Yuan, X.

    2012-12-01

    The satellite-derived sea surface temperature (SST) data, 1998-mid 2012, are used to examine intraseasonal variability (ISV; 20-90 days) across the Indonesian seas. The most energetic ISV is observed in the Banda Sea and across the Indo-Australia basin with an The satellite-derived sea surface temperature (SST) data, 1998-mid 2012, are used to examine intraseasonal variability (ISV; 20-90 days) across the Indonesian seas. The most energetic ISV is observed in the Banda Sea and across the Indo-Australia basin with an average SST standard deviation (STD) between 0.4-0.5°C, with strongest signature during boreal winter. What physical processes force the SST ISV variability within the Indonesian seas? Ocean process, sea-air interaction, or both? To help identify the main forcing, the satellite derived outgoing longwave radiation (OLR) and wind stress data in the region are examined. The OLR shows robust intraseasonal variations and is significantly correlated with the SST, particularly for variability with periods of 30-60 days, with OLR accounting for ~60-70% of the SST variance. The OLR is also maximum during boreal winter. Conversely, the surface wind may play insignificant role in perturbing the SST at intraseasonal timescales as shown by weak correlation between wind stress and SST. We thus suspect that the surface solar flux (suggested by the OLR) is likely more dominant than the surface turbulent heat flux (indicated by the surface wind) as the main source for the ISV in the SST in Indonesian seas. Furthermore the maximum OLR phase, coupled with a period of minimum mixed layer depth, may explain the strong SST variation during boreal winter in Indonesian seas. The influence of the Madden-Julian Oscillation (MJO) on the OLR and SST variability is currently being evaluated.

  2. Water in contact with extended hydrophobic surfaces: Direct evidence of weak dewetting

    International Nuclear Information System (INIS)

    Jensen, Torben R.; Kjaer, Kristian; Oestergaard Jensen, Morten; Peters, Guenther H.; Reitzel, Niels; Balashev, Konstantin; Bjoernholm, Thomas

    2003-01-01

    X-ray reflectivity measurements reveal a significant dewetting of a large hydrophobic paraffin surface floating on water. The dewetting phenomenon extends less than 15 A into the bulk water phase and results in an integrated density deficit of about one water molecule per 25-30 A 2 of water in contact with the paraffin surface. The results are supported by molecular dynamics simulations and related to the hydrophobic effect

  3. Turbocharger with variable nozzle having vane sealing surfaces

    Science.gov (United States)

    Arnold, Philippe [Hennecourt, FR; Petitjean, Dominique [Julienrupt, FR; Ruquart, Anthony [Thaon les Vosges, FR; Dupont, Guillaume [Thaon les Vosges, FR; Jeckel, Denis [Thaon les Vosges, FR

    2011-11-15

    A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

  4. Water in contact with extended hydrophobic surfaces: Direct evidence of weak dewetting

    DEFF Research Database (Denmark)

    Jensen, Torben René; Jensen, Morten Østergaard; Reitzel, Niels

    2003-01-01

    X-ray reflectivity measurements reveal a significant dewetting of a large hydrophobic paraffin surface floating on water. The dewetting phenomenon extends less than 15 Angstrom into the bulk water phase and results in an integrated density deficit of about one water molecule per 25-30 Angstrom(2...

  5. Climatic variability and trends in the surface waters of coastal British Columbia

    Science.gov (United States)

    Cummins, Patrick F.; Masson, Diane

    2014-01-01

    Multi-decadal records of monthly sea surface temperature (SST) and sea surface salinity (SSS) collected at a set of lighthouse stations are used to examine climatic variability and trends in the coastal waters of British Columbia. Particular attention is given to relations between the water property anomalies and variability in coastal freshwater discharge and alongshore wind stress. Within the Strait of Georgia, SSS anomalies are closely related to Fraser River discharge anomalies. Along the Pacific coast, anomalies in alongshore wind stress and freshwater runoff have the characteristics of white noise processes. A cross-correlation analysis demonstrates that SST and SSS variability along the open west coast is consistent with the response of a first-order autoregressive process driven by anomalous alongshore wind stress and coastal freshwater discharge, respectively. Thus climatic variability of SST and SSS along the Pacific coast of British Columbia occurs, in part, through the integration of noisy atmospheric forcing and coastal precipitation. Seasonal correlations show that SST is strongly related to wind stress during winter and fall. Conversely, SSS is relatively weakly related to the alongshore wind during spring, suggesting that variability in upwelling makes only a modest contribution to variability of SSS in the nearshore environment. Consistent with previous studies, secular trends indicate long-term warming and freshening of the coastal ocean at most stations. It is shown that long-term SST trends can be obscured by the pronounced climatic variability of these waters, requiring that time series extend for several decades to be reliably detected.

  6. Field emission and high voltage cleaning of particulate contaminants on extended metallic surfaces

    International Nuclear Information System (INIS)

    Tan, J.; Bonin, B.; Safa, H.

    1996-01-01

    The vacuum insulation properties of extended metallic surfaces depends strongly on their cleanliness. The usual technique to reduce electronic field emission from such surfaces consists in exposing them to very high electric fields during limited periods of time. This kind of processing also reduces the occurrence of vacuum breakdown. The processing of the surface is generally believed to be due to a thermomechanical destruction of the emitting sites, initiated by the emission itself. Comparison of the electric forces vs adherence forces which act on dust particles lying on the surface shows that the processing could also be due simply to the mechanical removal of the dust particles, with a subsequent reduction of field emission from the contaminated surface. (author)

  7. Are turtleback fault surfaces common structural elements of highly extended terranes?

    Science.gov (United States)

    Çemen, Ibrahim; Tekeli, Okan; Seyitoğlu, Gűrol; Isik, Veysel

    2005-12-01

    The Death Valley region of the U.S.A. contains three topographic surfaces resembling the carapace of a turtle. These three surfaces are well exposed along the Black Mountain front and are named the Badwater, Copper Canyon, and Mormon Point Turtlebacks. It is widely accepted that the turtlebacks are also detachment surfaces that separate brittlely deformed Cenozoic volcanic and sedimentary rocks of the hanging wall from the strongly mylonitic, ductilely deformed pre-Cenozoic rocks of the footwall. We have found a turtleback-like detachment surface along the southern margin of the Alasehir (Gediz) Graben in western Anatolia, Turkey. This surface qualifies as a turtleback fault surface because it (a) is overall convex-upward and (b) separates brittlely deformed hanging wall Cenozoic sedimentary rocks from the ductilely to brittlely deformed, strongly mylonitic pre-Cenozoic footwall rocks. The surface, named here Horzum Turtleback, contains striations that overprint mylonitic stretching lineations indicating top to the NE sense of shear. This suggests that the northeasterly directed Cenozoic extension in the region resulted in a ductile deformation at depth and as the crust isostatically adjusted to the removal of the rocks in the hanging wall of the detachment fault, the ductilely deformed mylonitic rocks of the footwall were brought to shallower depths where they were brittlely deformed. The turtleback surfaces have been considered unique to the Death Valley region, although detachment surfaces, rollover folds, and other extensional structures have been well observed in other extended terranes of the world. The presence of a turtleback fault surface in western Anatolia, Turkey, suggests that the turtleback faults may be common structural features of highly extended terranes.

  8. Interannual variability of north Atlantic Sea surface temperatures

    International Nuclear Information System (INIS)

    Bhatt, U.S.; Battisiti, D.S.; Alexander, M.A.

    1994-01-01

    In the midlatitude north Atlantic Ocean the pattern of sea surface temperature anomalies (ssta) is characterized by a north-south dipole. Bjerknes was the first to propose that the banded structure was associated with the interannual variability. Recently, these patterns have been studied more extensively. In this study the quantitative aspects of these patterns are examined through the use of a mixed-layer model (MLM)

  9. The spinning minimal surfaces without the Grassmann variables

    International Nuclear Information System (INIS)

    Barut, A.O.; Pavsic, M.

    1988-01-01

    Generalizing the model of the spinning Dirac electron with Zitterbewegung we give a theory of spinning strings, membranes and p-branes in curved background spaces of arbitrary dimensions. The dynamical variables are surface co-ordinates x μ (ξ α ) and a single c-number spinor z(ξ α ). We use a phase space action which reduces in the limit to that of spinless membranes. A Hamiltonian formulation is also given. (author). 8 refs

  10. Governance of extended lifecycle in large-scale eHealth initiatives: analyzing variability of enterprise architecture elements.

    Science.gov (United States)

    Mykkänen, Juha; Virkanen, Hannu; Tuomainen, Mika

    2013-01-01

    The governance of large eHealth initiatives requires traceability of many requirements and design decisions. We provide a model which we use to conceptually analyze variability of several enterprise architecture (EA) elements throughout the extended lifecycle of development goals using interrelated projects related to the national ePrescription in Finland.

  11. Isolate extended state in the DNA molecular transistor with surface interaction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Le, E-mail: wang_le917@gs.zzu.edu.cn; Qin, Zhi-Jie

    2016-02-01

    The field effect characteristic of a DNA molecular device is investigated in a tight binding model with binary disorder and side site correlation. Using the transfer-matrix method and Landauer–Büttiker theory, we find that the system has isolated extended state that is irrespective of the DNA sequence and can be modulated by the gate voltage. When the gate voltage reaches some proper value, the isolated extended state appears at the Fermi level of the system and the long range charge transport is greatly enhanced. We attribute this phenomenon to the combination of the external field, the surface interaction, and the intrinsic disorder of DNA. The result is a generic feature of the nanowire with binary disorder and surface interaction.

  12. Reflectance variability of surface coatings reveals characteristic eigenvalue spectra

    Science.gov (United States)

    Medina, José M.; Díaz, José A.; Barros, Rui

    2012-10-01

    We have examined the trial-to-trial variability of the reflectance spectra of surface coatings containing effect pigments. Principal component analysis of reflectances was done at each detection angle separately. A method for classification of principal components is applied based on the eigenvalue spectra. It was found that the eigenvalue spectra follow characteristic power laws and depend on the detection angle. Three different subsets of principal components were examined to separate the relevant spectral features related to the pigments from other noise sources. Reconstruction of the reflectance spectra by taking only the first subset indicated that reflectance variability was higher at near-specular reflection, suggesting a correlation with the trial-to-trial deposition of effect pigments. Reconstruction by using the second subset indicates that variability was higher at short wavelengths. Finally, reconstruction by using only the third subset indicates that reflectance variability was not totally random as a function of the wavelength. The methods employed can be useful in the evaluation of color variability in industrial paint application processes.

  13. Simple surface structure determination from Fourier transforms of angle-resolved photoemission extended fine structure

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Y. [Pennsylvania State Univ., University Park, PA (United States)]|[Lawrence Berkeley Lab., CA (United States); Shirley, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-02-01

    The authors show by Fourier analyses of experimental data, with no further treatment, that the positions of all the strong peaks in Fourier transforms of angle-resolved photoemission extended fine structure (ARPEFS) from adsorbed surfaces can be explicitly predicted from a trial structure with an accuracy of about {+-} 0.3 {angstrom} based on a single-scattering cluster model together with the concept of a strong backscattering cone, and without any additional analysis. This characteristic of ARPEFS Fourier transforms can be developed as a simple method for determining the structures of adsorbed surfaces to an accuracy of about {+-} 0.1 {angstrom}.

  14. Variability of emissivity and surface temperature over a sparsely vegetated surface

    International Nuclear Information System (INIS)

    Humes, K.S.; Kustas, W.P.; Moran, M.S.; Nichols, W.D.; Weltz, M.A.

    1994-01-01

    Radiometric surface temperatures obtained from remote sensing measurements are a function of both the physical surface temperature and the effective emissivity of the surface within the band pass of the radiometric measurement. For sparsely vegetated areas, however, a sensor views significant fractions of both bare soil and various vegetation types. In this case the radiometric response of a sensor is a function of the emissivities and kinetic temperatures of various surface elements, the proportion of those surface elements within the field of view of the sensor, and the interaction of radiation emitted from the various surface components. In order to effectively utilize thermal remote sensing data to quantify energy balance components for a sparsely vegetated area, it is important to examine the typical magnitude and degree of variability of emissivity and surface temperature for such surfaces. Surface emissivity measurements and ground and low-altitude-aircraft-based surface temperature measurements (8-13 micrometer band pass) made in conjunction with the Monsoon '90 field experiment were used to evaluate the typical variability of those quantities during the summer rainy season in a semiarid watershed. The average value for thermal band emissivity of the exposed bare soil portions of the surface was found to be approximately 0.96; the average value measured for most of the varieties of desert shrubs present was approximately 0.99. Surface composite emissivity was estimated to be approximately 0.98 for both the grass-dominated and shrub-dominated portions of the watershed. The spatial variability of surface temperature was found to be highly dependent on the spatial scale of integration for the instantaneous field of view (IFOV) of the instrument, the spatial scale of the total area under evaluation, and the time of day

  15. Dose distribution considerations of medium energy electron beams at extended source-to-surface distance

    International Nuclear Information System (INIS)

    Saw, Cheng B.; Ayyangar, Komanduri M.; Pawlicki, Todd; Korb, Leroy J.

    1995-01-01

    Purpose: To determine the effects of extended source-to-surface distance (SSD) on dose distributions for a range of medium energy electron beams and cone sizes. Methods and Materials: The depth-dose curves and isodose distributions of 6 MeV, 10 MeV, and 14 MeV electron beams from a dual photon and multielectron energies linear accelerator were studied. To examine the influence of cone size, the smallest and the largest cone sizes available were used. Measurements were carried out in a water phantom with the water surface set at three different SSDs from 101 to 116 cm. Results: In the region between the phantom surface and the depth of maximum dose, the depth-dose decreases as the SSD increases for all electron beam energies. The effects of extended SSD in the region beyond the depth of maximum dose are unobservable and, hence, considered minimal. Extended SSD effects are apparent for higher electron beam energy with small cone size causing the depth of maximum dose and the rapid dose fall-off region to shift deeper into the phantom. However, the change in the depth-dose curve is small. On the other hand, the rapid dose fall-off region is essentially unaltered when the large cone is used. The penumbra enlarges and electron beam flatness deteriorates with increasing SSD

  16. Chaos control of the micro-electro-mechanical resonator by using adaptive dynamic surface technology with extended state observer

    International Nuclear Information System (INIS)

    Luo, Shaohua; Sun, Quanping; Cheng, Wei

    2016-01-01

    This paper addresses chaos control of the micro-electro- mechanical resonator by using adaptive dynamic surface technology with extended state observer. To reveal the mechanism of the micro- electro-mechanical resonator, the phase diagrams and corresponding time histories are given to research the nonlinear dynamics and chaotic behavior, and Homoclinic and heteroclinic chaos which relate closely with the appearance of chaos are presented based on the potential function. To eliminate the effect of chaos, an adaptive dynamic surface control scheme with extended state observer is designed to convert random motion into regular motion without precise system model parameters and measured variables. Putting tracking differentiator into chaos controller solves the ‘explosion of complexity’ of backstepping and poor precision of the first-order filters. Meanwhile, to obtain high performance, a neural network with adaptive law is employed to approximate unknown nonlinear function in the process of controller design. The boundedness of all the signals of the closed-loop system is proved in theoretical analysis. Finally, numerical simulations are executed and extensive results illustrate effectiveness and robustness of the proposed scheme.

  17. Long-Term Variability of Surface Albedo and Its Correlation with Climatic Variables over Antarctica

    Directory of Open Access Journals (Sweden)

    Minji Seo

    2016-11-01

    Full Text Available The cryosphere is an essential part of the earth system for understanding climate change. Components of the cryosphere, such as ice sheets and sea ice, are generally decreasing over time. However, previous studies have indicated differing trends between the Antarctic and the Arctic. The South Pole also shows internal differences in trends. These phenomena indicate the importance of continuous observation of the Polar Regions. Albedo is a main indicator for analyzing Antarctic climate change and is an important variable with regard to the radiation budget because it can provide positive feedback on polar warming and is related to net radiation and atmospheric heating in the mainly snow- and ice-covered Antarctic. Therefore, in this study, we analyzed long-term temporal and spatial variability of albedo and investigated the interrelationships between albedo and climatic variables over Antarctica. We used broadband surface albedo data from the Satellite Application Facility on Climate Monitoring and data for several climatic variables such as temperature and Antarctic oscillation index (AAO during the period of 1983 to 2009. Time series analysis and correlation analysis were performed through linear regression using albedo and climatic variables. The results of this research indicated that albedo shows two trends, west trend and an east trend, over Antarctica. Most of the western side of Antarctica showed a negative trend of albedo (about −0.0007 to −0.0015 year−1, but the other side showed a positive trend (about 0.0006 year−1. In addition, albedo and surface temperature had a negative correlation, but this relationship was weaker in west Antarctica than in east Antarctica. The correlation between albedo and AAO revealed different relationships in the two regions; west Antarctica had a negative correlation and east Antarctica showed a positive correlation. In addition, the correlation between albedo and AAO was weaker in the west. This

  18. Experimental investigation on carbon nano tubes coated brass rectangular extended surfaces

    International Nuclear Information System (INIS)

    Senthilkumar, Rajendran; Prabhu, Sethuramalingam; Cheralathan, Marimuthu

    2013-01-01

    Finned surface has been extensively used for free convection cooling of internal combustion engines and several electronic kits etc. Here rectangular brass fin was preferred for analysis. Thermocouples were attached all over the surface of the fin in equal distances. The measurement of surface temperature and calculated convective heat transfer rate were reported for several heat input values. The overall system performance can be improved by enhancing heat transfer rate of extended surfaces. Based on the above requirement, brass surface was coated by carbon nano tubes. The temperature and heat transfer characteristics were investigated using Taguchi method for experimental design. Finally the performances of coated and non-coated rectangular brass fins were compared. The average percentage of increase in heat transfer rate was proved around 12% for carbon nanocoated rectangular brass fins. - Graphical abstract: The designed Natural and Forced convection Heat Transfer Test Rig measures the enhanced rate of heat transfer for nano coated rectangular fins than in non-coated fins. Highlights: ► Rectangular brass fins were preferred for convective heat transfer process. ► The rectangular brass fins are coated with multi wall carbon nano tubes in EBPVD process with nanometer thickness. ► Temperature and heat transfer rate were investigated for nanocoated and non-coated fins by using Taguchi method. ► Multi wall carbon nanotubes act as a pin fin to enhance surface area for effective convective heat transfer rate.

  19. Variability of Surface Reflection Amplitudes of GPR Horn Antenna Depending on Distance between Antenna and Surface

    Directory of Open Access Journals (Sweden)

    Komačka Jozef

    2016-05-01

    Full Text Available The study focused on variability of surface reflections amplitudes of GPR horn antenna in relation to distance between an antenna and a surface is presented in the paper. The air-coupled antenna with the central frequency of 1 GHz was used in the investigation. Four types of surfaces (dry pavement, wet pavement, metal plate and composite layer from gypsum and wood were tested. The distance of antenna above the surfaces was changed in the range from 37.5 cm to 53.5 cm. The amplitudes of negative and positive peaks and their variability were analysed in relation to the distance of antenna above the surfaces. Moreover, the influence of changes in the peaks of negative and positive amplitudes on the total amplitudes was assessed. It was found out the amplitudes of negative peaks for all investigated surfaces were relatively consistent in the range from 40.5 cm to 48.5 cm and the moderate decline was identified in the case of amplitudes of positive peaks in the range of distances from 37.5 cm to 51.5 cm. This decline influences the tendency of total amplitudes. Based on the results of analysis it can be stated the distance of air-coupled antenna above the surface can influence the value of total amplitude and the differences depend on the type of surface.

  20. Numerical studies on helium cooled divertor finger mock up with sectorial extended surfaces

    International Nuclear Information System (INIS)

    Rimza, Sandeep; Satpathy, Kamalakanta; Khirwadkar, Samir; Velusamy, Karupanna

    2014-01-01

    Highlights: • Studies on heat transfer enhancement for divertor finger mock-up. • Heat transfer characteristics of jet impingement with extended surfaces have been investigated. • Effect of critical parameters that influence the thermal performance of the finger mock-up by CFD approach. • Effect of extended surface in enhancing heat removal potential with pumping power assessed. • Practicability of the chosen design is verified by structural analysis. - Abstract: Jet impinging technique is an advance divertor concept for the design of future fusion power plants. This technique is extensively used due to its high heat removal capability with reasonable pumping power and for safe operation. In this design, plasma-facing components are fabricated with numerous fingers cooled by helium jets to reduce the thermal stresses. The present study is focused towards finding an optimum performance of one such finger mock-up through systematic computational fluid dynamics (CFD) studies. Heat transfer characteristics of jet impingement have been numerically investigated with sectorial extended surfaces (SES). The result shows that addition of SES enhances heat removal potential with minimum pumping power. Detailed parametric studies on critical parameters that influence thermal performance of the finger mock-up have been analyzed. Thermo-mechanical analysis has been carried out through finite element based approach to know the state of stress in the assembly as a result of large temperature gradients. It is seen that the stresses are within the permissible limits for the present design. The whole numerical simulation has been carried out using general-purpose CFD software (ANSYS FLUENT, Release 14.0, User Guide, Ansys, Inc., 2011). Benchmark validation studies have been performed against high-heat flux experiments (B. Končar, P. Norajitra, K. Oblak, Appl. Therm. Eng., 30, 697–705, 2010) and a good agreement is noticed between the present simulation and the reported

  1. On a model of mixtures with internal variables: Extended Liu procedure for the exploitation of the entropy principle

    Directory of Open Access Journals (Sweden)

    Francesco Oliveri

    2016-01-01

    Full Text Available The exploitation of second law of thermodynamics for a mixture of two fluids with a scalar internal variable and a first order nonlocal state space is achieved by using the extended Liu approach. This method requires to insert as constraints in the entropy inequality either the field equations or their gradient extensions. Consequently, the thermodynamic restrictions imposed by the entropy principle are derived without introducing extra terms neither in the energy balance equation nor in the entropy inequality.

  2. Surface extended x-ray absorption fine structure of low-Z absorbates using fluorescence detection

    International Nuclear Information System (INIS)

    Stoehr, J.; Kollin, E.B.; Fischer, D.A.; Hastings, J.B.; Zaera, F.; Sette, F.

    1985-05-01

    Comparison of x-ray fluorescence yield (FY) and electron yield surface extended x-ray absorption fine structure spectra above the S K-edge for c(2 x 2) S on Ni(100) reveals an order of magnitude higher sensitivity of the FY technique. Using FY detection, thiophene (C 4 H 4 S) chemisorption on Ni(100) is studied with S coverages down to 0.08 monolayer. The molecule dissociates at temperatures as low as 100K by interaction with fourfold hollow Ni sites. Blocking of these sites by oxygen leaves the molecule intact

  3. Contemporary internal auditing practices : (new) roles and influencing variables. Evidence from extended case studies

    OpenAIRE

    G. SARENS; I. DE BEELDE

    2004-01-01

    Following the recommendation made by Rittenberg (1999), this study encompasses the broader nature of internal auditing that is evolving in practice and confirmed by the revised definition of internal auditing and the new Professional Practices Framework, both issued by the IIA in 1999. This study, based on six extended case studies, attempts to contribute to the literature by studying contemporary internal auditing practices in Belgium (assurance and / or consulting oriented), refining the in...

  4. Airborne Optical Remote Sensing of Ocean Surface Current Variability

    Science.gov (United States)

    Anderson, S. P.; Zuckerman, S.; Stuart, G.

    2016-02-01

    Accurate and timely knowledge of open ocean surface currents are needed for a variety of engineering and emergency missions, as well as for improving scientific understanding of ocean dynamics. This paper presents surface current observations from a new airborne current measurement capability called the Remote Ocean Current Imaging System (ROCIS). ROCIS exploits space-time processing of airborne ocean wave imagery to produce real-time maps of surface currents every 1 km along the flight track. Post-processing of the data allows for more in depth sensitivity studies than can be undertaken with the real-time measurements alone, providing swaths of current retrievals at higher spatial resolutions. Currents can be calculated on scales down to 100 m, across swaths 3 km wide, along the entire flight path. Here, we report on results for multiple ROCIS data collection flights over the Gulf of Mexico conducted in 2012, 2014 and 2015. We show comparisons to in situ current measurements, explore performance as a function of altitude, dwell, wind speed, and wave height, and discuss sources of error. We present examples of current retrievals revealing mesoscale and submesoscale variability. Lastly, we present horizontal kinetic energy spectra from select flights covering a range of spatial scales from hundreds of meters to hundreds of kilometers.

  5. Interannual variability of surface and bottom sediment transport on the Laptev Sea shelf during summer

    Directory of Open Access Journals (Sweden)

    C. Wegner

    2013-02-01

    Full Text Available Sediment transport dynamics were studied during ice-free conditions under different atmospheric circulation regimes on the Laptev Sea shelf (Siberian Arctic. To study the interannual variability of suspended particulate matter (SPM dynamics and their coupling with the variability in surface river water distribution on the Laptev Sea shelf, detailed oceanographic, optical (turbidity and Ocean Color satellite data, and hydrochemical (nutrients, SPM, stable oxygen isotopes process studies were carried out continuously during the summers of 2007 and 2008. Thus, for the first time SPM and nutrient variations on the Laptev Sea shelf under different atmospheric forcing and the implications for the turbidity and transparency of the water column can be presented.

    The data indicate a clear link between different surface distributions of riverine waters and the SPM transport dynamics within the entire water column. The summer of 2007 was dominated by shoreward winds and an eastward transport of riverine surface waters. The surface SPM concentration on the southeastern inner shelf was elevated, which led to decreased transmissivity and increased light absorption. Surface SPM concentrations in the central and northern Laptev Sea were comparatively low. However, the SPM transport and concentration within the bottom nepheloid layer increased considerably on the entire eastern shelf. The summer of 2008 was dominated by offshore winds and northward transport of the river plume. The surface SPM transport was enhanced and extended onto the mid-shelf, whereas the bottom SPM transport and concentration was diminished. This study suggests that the SPM concentration and transport, in both the surface and bottom nepheloid layers, are associated with the distribution of riverine surface waters which are linked to the atmospheric circulation patterns over the Laptev Sea and the adjacent Arctic Ocean during the open water season. A continuing trend toward

  6. Simulation of an extended surface detector IceVeto for IceCube-Gen2

    Energy Technology Data Exchange (ETDEWEB)

    Hansmann, Tim; Auffenberg, Jan; Haack, Christian; Hansmann, Bengt; Kemp, Julian; Konietz, Richard; Leuner, Jakob; Raedel, Leif; Stahlberg, Martin; Schoenen, Sebastian; Wiebusch, Christopher [III. Physikalisches Institut B, RWTH Aachen University (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    IceCube is a neutrino observatory located at the geographic South Pole. The main backgrounds for IceCube's primary goal, the measurement of astrophysical neutrinos, are muons and neutrinos from cosmic-ray air showers in the Earth's atmosphere. Strong supression of these backgrounds from the Southern hemisphere has been demonstrated by coincident detection of these air showers with the IceTop surface detector. For an extended instrument, IceCube-Gen2, it is considered to build an enlarged surface array, IceVeto, that will improve the detection capabilities of coincident air showers. We will present simulation studies to estimate the IceVeto capabilities to optimize the IceCube-Gen2 design.

  7. ESA STSE “SST Diurnal Variability: Regional Extend - Implications in Atmospheric Modelling”

    DEFF Research Database (Denmark)

    Karagali, Ioanna

    The diurnal variability of SST, driven by the coincident occurrence of low enough wind and solar heating, has been observed in various regions of the global ocean [4, 5, 6]. Atmospheric, oceanic and climate models are not adequately resolving the daily SST cycle, resulting in biases of the total...

  8. Extending the Constant Coefficient Solution Technique to Variable Coefficient Ordinary Differential Equations

    Science.gov (United States)

    Mohammed, Ahmed; Zeleke, Aklilu

    2015-01-01

    We introduce a class of second-order ordinary differential equations (ODEs) with variable coefficients whose closed-form solutions can be obtained by the same method used to solve ODEs with constant coefficients. General solutions for the homogeneous case are discussed.

  9. Influence of Post-Mortem Sperm Recovery Method and Extender on Unstored and Refrigerated Rooster Sperm Variables.

    Science.gov (United States)

    Villaverde-Morcillo, S; Esteso, M C; Castaño, C; Santiago-Moreno, J

    2016-02-01

    Many post-mortem sperm collection techniques have been described for mammalian species, but their use in birds is scarce. This paper compares the efficacy of two post-mortem sperm retrieval techniques - the flushing and float-out methods - in the collection of rooster sperm, in conjunction with the use of two extenders, i.e., L&R-84 medium and Lake 7.1 medium. To determine whether the protective effects of these extenders against refrigeration are different for post-mortem and ejaculated sperm, pooled ejaculated samples (procured via the massage technique) were also diluted in the above extenders. Post-mortem and ejaculated sperm variables were assessed immediately at room temperature (0 h), and after refrigeration at 5°C for 24 and 48 h. The flushing method retrieved more sperm than the float-out method (596.5 ± 75.4 million sperm vs 341.0 ± 87.6 million sperm; p < 0.05); indeed, the number retrieved by the former method was similar to that obtained by massage-induced ejaculation (630.3 ± 78.2 million sperm). For sperm collected by all methods, the L&R-84 medium provided an advantage in terms of sperm motility variables at 0 h. In the refrigerated sperm samples, however, the Lake 7.1 medium was associated with higher percentages of viable sperm, and had a greater protective effect (p < 0.05) with respect to most motility variables. In conclusion, the flushing method is recommended for collecting sperm from dead birds. If this sperm needs to be refrigerated at 5°C until analysis, Lake 7.1 medium is recommended as an extender. © 2015 Blackwell Verlag GmbH.

  10. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    Science.gov (United States)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  11. White Dwarfs in Cataclysmic Variable Stars: Surface Temperatures and Evolution

    Directory of Open Access Journals (Sweden)

    Edward M. Sion

    2012-06-01

    Full Text Available A summary is presented of what is currently known about the surface temperatures of accreting white dwarfs (WDs detected in non-magnetic and magnetic cataclysmic variables (CVs based upon synthetic spectral analyses of far ultraviolet data. A special focus is placed on WD temperatures above and below the CV period gap as a function of the orbital period, Porb. The principal uncertainty of the temperatures for the CV WDs in the Teff - Porb distribution, besides the distance to the CV, is the mass of the WD. Only in eclipsing CV systems, an area of eclipsing binary studies, which was so central to Robert H. Koch’s career, is it possible to know CV WD masses with high precision.

  12. Frost Growth and Densification on a Flat Surface in Laminar Flow with Variable Humidity

    Science.gov (United States)

    Kandula, M.

    2012-01-01

    Experiments are performed concerning frost growth and densification in laminar flow over a flat surface under conditions of constant and variable humidity. The flat plate test specimen is made of aluminum-6031, and has dimensions of 0.3 mx0.3 mx6.35 mm. Results for the first variable humidity case are obtained for a plate temperature of 255.4 K, air velocity of 1.77 m/s, air temperature of 295.1 K, and a relative humidity continuously ranging from 81 to 54%. The second variable humidity test case corresponds to plate temperature of 255.4 K, air velocity of 2.44 m/s, air temperature of 291.8 K, and a relative humidity ranging from 66 to 59%. Results for the constant humidity case are obtained for a plate temperature of 263.7 K, air velocity of 1.7 m/s, air temperature of 295 K, and a relative humidity of 71.6 %. Comparisons of the data with the author's frost model extended to accommodate variable humidity suggest satisfactory agreement between the theory and the data for both constant and variable humidity.

  13. Highly variable Pliocene sea surface conditions in the Norwegian Sea

    Directory of Open Access Journals (Sweden)

    P. E. Bachem

    2017-09-01

    Full Text Available The Pliocene was a time of global warmth with small sporadic glaciations, which transitioned towards the larger-scale Pleistocene glacial–interglacial variability. Here, we present high-resolution records of sea surface temperature (SST and ice-rafted debris (IRD in the Norwegian Sea from 5.32 to 3.14 Ma, providing evidence that the Pliocene surface conditions of the Norwegian Sea underwent a series of transitions in response to orbital forcing and gateway changes. Average SSTs are 2 °C above the regional Holocene mean, with notable variability on millennial to orbital timescales. Both gradual changes and threshold effects are proposed for the progression of regional climate towards the Late Pliocene intensification of Northern Hemisphere glaciation. Cooling from 4.5 to 4.3 Ma may be linked to the onset of poleward flow through the Bering Strait. This cooling was further intensified by a period of cool summers due to weak obliquity forcing. A 7 °C warming of the Norwegian Sea at 4.0 Ma suggests a major increase in northward heat transport from the North Atlantic, leading to an enhanced zonal SST gradient in the Nordic Seas, which may be linked to the expansion of sea ice in the Arctic and Nordic Seas. A warm Norwegian Sea and enhanced zonal temperature gradient between 4.0 and 3.6 Ma may have been a priming factor for increased glaciation around the Nordic Seas due to enhanced evaporation and precipitation at high northern latitudes.

  14. An extended validation of the last generation of particle finite element method for free surface flows

    Science.gov (United States)

    Gimenez, Juan M.; González, Leo M.

    2015-03-01

    In this paper, a new generation of the particle method known as Particle Finite Element Method (PFEM), which combines convective particle movement and a fixed mesh resolution, is applied to free surface flows. This interesting variant, previously described in the literature as PFEM-2, is able to use larger time steps when compared to other similar numerical tools which implies shorter computational times while maintaining the accuracy of the computation. PFEM-2 has already been extended to free surface problems, being the main topic of this paper a deep validation of this methodology for a wider range of flows. To accomplish this task, different improved versions of discontinuous and continuous enriched basis functions for the pressure field have been developed to capture the free surface dynamics without artificial diffusion or undesired numerical effects when different density ratios are involved. A collection of problems has been carefully selected such that a wide variety of Froude numbers, density ratios and dominant dissipative cases are reported with the intention of presenting a general methodology, not restricted to a particular range of parameters, and capable of using large time-steps. The results of the different free-surface problems solved, which include: Rayleigh-Taylor instability, sloshing problems, viscous standing waves and the dam break problem, are compared to well validated numerical alternatives or experimental measurements obtaining accurate approximations for such complex flows.

  15. Multidecadal Variability in Surface Albedo Feedback Across CMIP5 Models

    Science.gov (United States)

    Schneider, Adam; Flanner, Mark; Perket, Justin

    2018-02-01

    Previous studies quantify surface albedo feedback (SAF) in climate change, but few assess its variability on decadal time scales. Using the Coupled Model Intercomparison Project Version 5 (CMIP5) multimodel ensemble data set, we calculate time evolving SAF in multiple decades from surface albedo and temperature linear regressions. Results are meaningful when temperature change exceeds 0.5 K. Decadal-scale SAF is strongly correlated with century-scale SAF during the 21st century. Throughout the 21st century, multimodel ensemble mean SAF increases from 0.37 to 0.42 W m-2 K-1. These results suggest that models' mean decadal-scale SAFs are good estimates of their century-scale SAFs if there is at least 0.5 K temperature change. Persistent SAF into the late 21st century indicates ongoing capacity for Arctic albedo decline despite there being less sea ice. If the CMIP5 multimodel ensemble results are representative of the Earth, we cannot expect decreasing Arctic sea ice extent to suppress SAF in the 21st century.

  16. Extended volume and surface scatterometer for optical characterization of 3D-printed elements

    Science.gov (United States)

    Dannenberg, Florian; Uebeler, Denise; Weiß, Jürgen; Pescoller, Lukas; Weyer, Cornelia; Hahlweg, Cornelius

    2015-09-01

    The use of 3d printing technology seems to be a promising way for low cost prototyping, not only of mechanical, but also of optical components or systems. It is especially useful in applications where customized equipment repeatedly is subject to immediate destruction, as in experimental detonics and the like. Due to the nature of the 3D-printing process, there is a certain inner texture and therefore inhomogeneous optical behaviour to be taken into account, which also indicates mechanical anisotropy. Recent investigations are dedicated to quantification of optical properties of such printed bodies and derivation of corresponding optimization strategies for the printing process. Beside mounting, alignment and illumination means, also refractive and reflective elements are subject to investigation. The proposed measurement methods are based on an imaging nearfield scatterometer for combined volume and surface scatter measurements as proposed in previous papers. In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. The device has been extended for observation of photoelasticity effects and therefore homogeneity of polarization behaviour. A refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of the layers of the surface under test, cross and parallel polarization techniques are applied. Practical examples from current research studies are included.

  17. Surface Estimation, Variable Selection, and the Nonparametric Oracle Property.

    Science.gov (United States)

    Storlie, Curtis B; Bondell, Howard D; Reich, Brian J; Zhang, Hao Helen

    2011-04-01

    Variable selection for multivariate nonparametric regression is an important, yet challenging, problem due, in part, to the infinite dimensionality of the function space. An ideal selection procedure should be automatic, stable, easy to use, and have desirable asymptotic properties. In particular, we define a selection procedure to be nonparametric oracle (np-oracle) if it consistently selects the correct subset of predictors and at the same time estimates the smooth surface at the optimal nonparametric rate, as the sample size goes to infinity. In this paper, we propose a model selection procedure for nonparametric models, and explore the conditions under which the new method enjoys the aforementioned properties. Developed in the framework of smoothing spline ANOVA, our estimator is obtained via solving a regularization problem with a novel adaptive penalty on the sum of functional component norms. Theoretical properties of the new estimator are established. Additionally, numerous simulated and real examples further demonstrate that the new approach substantially outperforms other existing methods in the finite sample setting.

  18. Influence diagram of physiological and environmental factors affecting heart rate variability: an extended literature overview

    Directory of Open Access Journals (Sweden)

    Julien Fatisson

    2016-09-01

    Full Text Available Heart rate variability (HRV corresponds to the adaptation of the heart to any stimulus. In fact, among the pathologies affecting HRV the most, there are the cardiovascular diseases and depressive disorders, which are associated with high medical cost in Western societies. Consequently, HRV is now widely used as an index of health.In order to better understand how this adaptation takes place, it is necessary to examine which factors directly influence HRV, whether they have a physiological or environmental origin. The primary objective of this research is therefore to conduct a literature review in order to get a comprehensive overview of the subject.The system of these factors affecting HRV can be divided into the following five categories: physiological and pathological factors, environmental factors, lifestyle factors, non-modifiable factors and effects. The direct interrelationships between these factors and HRV can be regrouped into an influence diagram. This diagram can therefore serve as a basis to improve daily clinical practice as well as help design even more precise research protocols.

  19. Boar variability in sperm cryo-tolerance after cooling of semen in different long-term extenders at various temperatures.

    Science.gov (United States)

    Wasilewska, K; Fraser, L

    2017-10-01

    This study investigated individual boar variability in the quality of pre-freeze (PF) and post-thaw (PT) semen cooled in different long-term (LT) extenders and for different holding times (HT). Sperm rich fractions were diluted with Androhep ® Plus (AHP), Androstar ® Plus (ASP), Safecell ® Plus (SCP) and TRIXcell ® Plus (TCP) extenders, stored for 2h at 17°C (HT 1) and additionally for 24h at 10°C (HT 2) and the samples were subsequently evaluated and frozen. Besides the analysis of CASA sperm variables, mitochondrial membrane potential (MMP), plasma membrane integrity (PMI), normal apical ridge (NAR) acrosome integrity, and viability (YO-PRO-1 - /PI - ) of sperm were assessed in the PF and PT semen. Results indicated that boar, extender and HT group affected the sperm quality characteristics. There were great variations in PMOT and the sperm motion patterns of the PF semen among the boars. Differences in the HT groups of the PF semen, with respect to the sperm membrane integrity, were less marked among the boars. Consistent variations in TMOT and PMOT in the PT semen were observed among the boars, being greater in the HT 2 group. Most of the CASA-analyzed sperm motion patterns were greater in the HT 2 group of the PT semen. Furthermore, sperm MMP, PMI and viability were greater in the HT 2 group of the PT semen in most of the boars, while consistent differences were observed among the boars for sperm NAR acrosome integrity in either HT group. The significant effect of the cryopreservation process on the sperm membrane proteome was evident from the number of protein bands, detected in the electrophoretic profiles of sperm of the HT 1 and HT 2 groups. The electrophoretic profiles of the PF and PT semen among boars with poor and good semen freezability, however, differed with respect to the abundance and types of sperm membrane-associated proteins. The overall results of this study provided evidence that there are differences among boars in response to the

  20. Comparisons of predicted steady-state levels in rooms with extended- and local-reaction bounding surfaces

    Science.gov (United States)

    Hodgson, Murray; Wareing, Andrew

    2008-01-01

    A combined beam-tracing and transfer-matrix model for predicting steady-state sound-pressure levels in rooms with multilayer bounding surfaces was used to compare the effect of extended- and local-reaction surfaces, and the accuracy of the local-reaction approximation. Three rooms—an office, a corridor and a workshop—with one or more multilayer test surfaces were considered. The test surfaces were a single-glass panel, a double-drywall panel, a carpeted floor, a suspended-acoustical ceiling, a double-steel panel, and glass fibre on a hard backing. Each test surface was modeled as of extended or of local reaction. Sound-pressure levels were predicted and compared to determine the significance of the surface-reaction assumption. The main conclusions were that the difference between modeling a room surface as of extended or of local reaction is not significant when the surface is a single plate or a single layer of material (solid or porous) with a hard backing. The difference is significant when the surface consists of multilayers of solid or porous material and includes a layer of fluid with a large thickness relative to the other layers. The results are partially explained by considering the surface-reflection coefficients at the first-reflection angles.

  1. Extended-range forecasting of Chinese summer surface air temperature and heat waves

    Science.gov (United States)

    Zhu, Zhiwei; Li, Tim

    2018-03-01

    Because of growing demand from agricultural planning, power management and activity scheduling, extended-range (5-30-day lead) forecasting of summer surface air temperature (SAT) and heat waves over China is carried out in the present study via spatial-temporal projection models (STPMs). Based on the training data during 1960-1999, the predictability sources are found to propagate from Europe, Northeast Asia, and the tropical Pacific, to influence the intraseasonal 10-80 day SAT over China. STPMs are therefore constructed using the projection domains, which are determined by these previous predictability sources. For the independent forecast period (2000-2013), the STPMs can reproduce EOF-filtered 30-80 day SAT at all lead times of 5-30 days over most part of China, and observed 30-80 and 10-80 day SAT at 25-30 days over eastern China. Significant pattern correlation coefficients account for more than 50% of total forecasts at all 5-30-day lead times against EOF-filtered and observed 30-80 day SAT, and at a 20-day lead time against observed 10-80 day SAT. The STPMs perform poorly in reproducing 10-30 day SAT. Forecasting for the first two modes of 10-30 day SAT only shows useful skill within a 15-day lead time. Forecasting for the third mode of 10-30 day SAT is useless after a 10-day lead time. The forecasted heat waves over China are determined by the reconstructed SAT which is the summation of the forecasted 10-80 day SAT and the lower frequency (longer than 80-day) climatological SAT. Over a large part of China, the STPMs can forecast more than 30% of heat waves within a 15-day lead time. In general, the STPMs demonstrate the promising skill for extended-range forecasting of Chinese summer SAT and heat waves.

  2. The 3D Mesonet Concept: Extending Networked Surface Meteorological Tower Observations Through Unmanned Aircraft Systems

    Science.gov (United States)

    Chilson, P. B.; Fiebrich, C. A.; Huck, R.; Grimsley, J.; Salazar-Cerreno, J.; Carson, K.; Jacob, J.

    2017-12-01

    Fixed monitoring sites, such as those in the US National Weather Service Automated Surface Observing System (ASOS) and the Oklahoma Mesonet provide valuable, high temporal resolution information about the atmosphere to forecasters and the general public. The Oklahoma Mesonet is comprised of a network of 120 surface sites providing a wide array of atmospheric measurements up to a height of 10 m with an update time of five minutes. The deployment of small unmanned aircraft to collect in-situ vertical measurements of the atmospheric state in conjunction with surface conditions has potential to significantly expand weather observation capabilities. This concept can enhance the safety of individuals and support commerce through improved observations and short-term forecasts of the weather and other environmental variables in the lower atmosphere. We report on a concept of adding the capability of collecting vertical atmospheric measurements (profiles) through the use of unmanned aerial systems (UAS) at remote Oklahoma sites deemed suitable for this application. While there are a number of other technologies currently available that can provide measurements of one or a few variables, the proposed UAS concept will be expandable and modular to accommodate several different sensor packages and provide accurate in-situ measurements in virtually all weather conditions. Such a system would facilitate off-site maintenance and calibration and would provide the ability to add new sensors as they are developed or as new requirements are identified. The small UAS must be capable of accommodating the weight of all sensor packages and have lighting, communication, and aircraft avoidance systems necessary to meet existing or future FAA regulations. The system must be able to operate unattended, which necessitates the inclusion of risk mitigation measures such as a detect and avoid radar and the ability to transmit and receive transponder signals. Moreover, the system should be able to

  3. Comparison of limb kinematics between collected and lengthened (medium/extended) trot in two groups of dressage horses on two different surfaces.

    Science.gov (United States)

    Walker, V A; Tranquille, C A; Newton, J R; Dyson, S J; Brandham, J; Northrop, A J; Murray, R C

    2017-09-01

    Dressage horses are often asked to work in lengthened paces during training and competition, but to date there is limited information about the biomechanics of dressage-specific paces. Preliminary work has shown increased fetlock extension in extended compared with collected paces, but further investigation of the kinematic differences between collected, medium and extended trot in dressage horses is warranted. Investigation of the effect of collected vs. medium/extended trot on limb kinematics of dressage horses. Prospective kinematic evaluation. Twenty clinically sound horses in active dressage training were used. Group 1: Ten young horses (≤6 years) were assessed at collected and medium trot and Group 2: Ten mature horses (≥9 years) were assessed at collected and extended trot. All horses were evaluated on two different surfaces. High speed motion capture (240 Hz) was used to determine kinematic variables. Fore- and hindlimb angles were measured at mid-stance. Descriptive statistics and mixed effect multilevel regression analyses were performed. Speed and stride length were reduced and stride duration increased at collected compared with medium/extended trot. Lengthened trot (medium/extended trot) was associated with increased fetlock extension in both the fore- and hindlimbs in both groups of horses. Changes were greater in mature horses compared with young horses. Shoulder and carpus angles were associated with forelimb fetlock angle. Hock angle was not significantly influenced by pace. Surface had no effect on fetlock or hock angles. Only 2D motion analysis was carried out. Results may have differed in horses with more extreme gait characteristics. Medium/extended trot increases extension of the fore- and hindlimb fetlock joints compared with collected trot in both young and mature dressage horses, respectively. © 2017 EVJ Ltd.

  4. Pathogenic Escherichia coli producing Extended-Spectrum β-Lactamases isolated from surface water and wastewater.

    Science.gov (United States)

    Franz, Eelco; Veenman, Christiaan; van Hoek, Angela H A M; de Roda Husman, Ana; Blaak, Hetty

    2015-09-24

    To assess public health risks from environmental exposure to Extended-Spectrum β-Lactamases (ESBL)-producing bacteria, it is necessary to have insight in the proportion of relative harmless commensal variants and potentially pathogenic ones (which may directly cause disease). In the current study, 170 ESBL-producing E. coli from Dutch wastewater (n = 82) and surface water (n = 88) were characterized with respect to ESBL-genotype, phylogenetic group, resistance phenotype and virulence markers associated with enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), extraintesinal E. coli (ExPEC), and Shiga toxin-producing E. coli (STEC). Overall, 17.1% of all ESBL-producing E. coli were suspected pathogenic variants. Suspected ExPECs constituted 8.8% of all ESBL-producing variants and 8.3% were potential gastrointestinal pathogens (4.1% EAEC, 1.8% EPEC, 1.2% EIEC, 1.2% ETEC, no STEC). Suspected pathogens were significantly associated with ESBL-genotype CTX-M-15 (X(2) = 14.7, P antibiotics. In conclusion, this study demonstrates that the aquatic environment is a potential reservoir of E. coli variants that combine ESBL-genes, a high level of multi-drug resistance and virulence factors, and therewith pose a health risk to humans upon exposure.

  5. Processes of India's offshore summer intraseasonal sea surface temperature variability

    Digital Repository Service at National Institute of Oceanography (India)

    Kurian, N.; Lengaigne, M.; Gopalakrishna, V.V.; Vialard, J.; Pous, S.; Peter, A-C.; Durand, F.; Naik, Shweta

    study, we use an eddy-permitting 0.25 degrees regional ocean model to investigate mechanisms of this offshore intraseasonal SST variability. Modelled climatological mixed layer and upper thermocline depth are in very good agreement with estimates from...

  6. Variability of surface ozone with cloud coverage over Kolkata, India

    Indian Academy of Sciences (India)

    Critical analysis of experimental surface ozone data and cloud coverage is reported over Kolkata during the period January 2011 to December 2011. Significant relationship between these two parameters is observed. Analysis shows that the trend of surface ozone concentration and cloud coverage follow opposite ...

  7. Temporal and Spatial Variabilities of Japan Sea Surface Temperature and Atmospheric Forcings

    National Research Council Canada - National Science Library

    Chu, Peter C; Chen, Yuchun; Lu, Shihua

    1998-01-01

    ...) and surface air temperature (SAT) data during 1982-1994 and the National Center for Atmospheric Research surface wind stress curl data during 1982-1989 to investigate the Japan Sea SST temporal and spatial variabilities...

  8. Self-assembling peptide detergents stabilize isolated photosystem ion a dry surface for an extended time.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available We used a class of designed peptide detergents to stabilize photosystem I (PS-I upon extended drying under N2 on a gold-coated-Ni-NTA glass surface. PS-I is a chlorophyll-containing membrane protein complex that is the primary reducer of ferredoxin and the electron acceptor of plastocyanin. We isolated the complex from the thylakoids of spinach chloroplasts using a chemical detergent. The chlorophyll molecules associated with the PS-I complex provide an intrinsic steady-state emission spectrum between 650 and 800 nm at -196.15 degrees C that reflects the organization of the pigment-protein interactions. In the absence of detergents, a large blue shift of the fluorescence maxima from approximately 735 nm to approximately 685 nm indicates a disruption in light-harvesting subunit organization, thus revealing chlorophyll-protein interactions. The commonly used membrane protein-stabilizing detergents, N-dodecyl-beta-D-maltoside and N-octyl-beta-D-glucoside, only partially stabilized the approximately 735-nm complex with approximately 685-nm spectroscopic shift. However, prior to drying, addition of the peptide detergent acetyl-AAAAAAK at increasing concentration significantly stabilized the PS-I complex. Moreover, in the presence of acetyl-AAAAAAK, the PS-I complex is stable in a dried form at room temperature for at least 3 wk. Another peptide detergent, acetyl-VVVVVVD, also stabilized the complex but to a lesser extent. These observations suggest that the peptide detergents may effectively stabilize membrane proteins in the solid-state. These designed peptide detergents may facilitate the study of diverse types of membrane proteins.

  9. Variability of surface meteorological parameters over the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Fernandes, A.A

    different parameters shows that the sea surface temperature and air temperature are positively and significantly correlated over the study area. A similar relationship is found between wind speed and cloudiness amount. Wind speed and cloudiness...

  10. An Exploratory Analysis of Corrective Maintenance During Extended Surface Ship Deployments

    National Research Council Canada - National Science Library

    Werenskjold, G

    1998-01-01

    This thesis illustrates the use of simulation techniques to evaluate the corrective maintenance requirements, and resulting operational availability on-station, for a ship deployed for an extended period of three years...

  11. Variability of surface ozone with cloud coverage over Kolkata, India

    Indian Academy of Sciences (India)

    influences the weather and climate of a place, thus acting as an ... earth by absorbing the most energetic part of the ... effect of cloud coverage on the surface ozone over. Kolkata. 2. ..... Burrows W R 1997 CART regression models for predicting.

  12. Variability in chemistry of surface and soil waters of an ...

    African Journals Online (AJOL)

    Water chemistry is important for the maintenance of wetland structure and function. Interpreting ecological patterns in a wetland system therefore requires an in-depth understanding of the water chemistry of that system. We investigated the spatial distribution of chemical solutes both in soil pore water and surface water, ...

  13. Biofilm retention on surfaces with variable roughness and hydrophobicity

    DEFF Research Database (Denmark)

    Tang, Lone; Pillai, Saju; Revsbech, Niels Peter

    2011-01-01

    Biofilms on food processing equipment cause food spoilage and pose a hazard to consumers. The bacterial community on steel surfaces in a butcher’s shop was characterized, and bacteria representative of this community enriched from minced pork were used to study biofilm retention. Stainless steel...

  14. Deep reversible storage - proposition of an area of interest for an extended survey and of surface implantation scenarios

    International Nuclear Information System (INIS)

    2009-01-01

    This document first describes the approach taken for the selection of a site. It presents and discusses the implantation criteria with respect to geology and to long term safety, the technical criteria for a surface implantation (environmental and safety constraints, social and economical data, transport infrastructures). Then, it states the first propositions for different scenarios of surface and underground implantations. It gives an assessment of the dialog with local actors. It presents the ANDRA's proposition in terms of technical criteria, area of interest for an extended survey, and surface implantation scenarios to be investigated

  15. Spatio-temporal Variability in Surface Ocean pCO2 Inferred from Observations

    OpenAIRE

    Jones, Steve

    2012-01-01

    The variability of surface ocean pCO2 is examined on multiple spatial and temporal scales. Temporal autocorrelation analysis is used to examine pCO2 variability over multiple years. Spatial autocorrelation analysis describes pCO2 variability over multiple spatial scales. Spatial autocorrelation lengths range between

  16. Weekly variability of surface CO concentrations in Moscow

    Science.gov (United States)

    Sitnov, S. A.; Adiks, T. G.

    2014-03-01

    Based on observations of carbon monoxide (CO) concentrations at three Mosekomonitoring stations, we have analyzed the weekly cycle of CO in the surface air of Moscow in 2004-2007. At all stations the minimum long-term mean daily CO values are observed on Sunday. The weekly cycle of CO more clearly manifests itself at the center of Moscow and becomes less clear closer to the outskirts. We have analyzed the reproducibility of the weekly cycle of CO from one year to another, the seasonal dependence, its specific features at different times of day, and the changes in the diurnal cycle of CO during the week. The factors responsible for specific features of the evolution of surface CO concentrations at different observation stations have been analyzed. The empirical probability density functions of CO concentrations on weekdays and at week- end are presented. The regularity of the occurrence of the weekend effect in CO has been investigated and the possible reasons for breaks in weekly cycles have been analyzed. The Kruskal-Wallis test was used to study the statistical significance of intraweek differences in surface CO contents.

  17. Downscaling reanalysis data to high-resolution variables above a glacier surface (Cordillera Blanca, Peru)

    Science.gov (United States)

    Hofer, Marlis; Mölg, Thomas; Marzeion, Ben; Kaser, Georg

    2010-05-01

    Recently initiated observation networks in the Cordillera Blanca provide temporally high-resolution, yet short-term atmospheric data. The aim of this study is to extend the existing time series into the past. We present an empirical-statistical downscaling (ESD) model that links 6-hourly NCEP/NCAR reanalysis data to the local target variables, measured at the tropical glacier Artesonraju (Northern Cordillera Blanca). The approach is particular in the context of ESD for two reasons. First, the observational time series for model calibration are short (only about two years). Second, unlike most ESD studies in climate research, we focus on variables at a high temporal resolution (i.e., six-hourly values). Our target variables are two important drivers in the surface energy balance of tropical glaciers; air temperature and specific humidity. The selection of predictor fields from the reanalysis data is based on regression analyses and climatologic considerations. The ESD modelling procedure includes combined empirical orthogonal function and multiple regression analyses. Principal component screening is based on cross-validation using the Akaike Information Criterion as model selection criterion. Double cross-validation is applied for model evaluation. Potential autocorrelation in the time series is considered by defining the block length in the resampling procedure. Apart from the selection of predictor fields, the modelling procedure is automated and does not include subjective choices. We assess the ESD model sensitivity to the predictor choice by using both single- and mixed-field predictors of the variables air temperature (1000 hPa), specific humidity (1000 hPa), and zonal wind speed (500 hPa). The chosen downscaling domain ranges from 80 to 50 degrees west and from 0 to 20 degrees south. Statistical transfer functions are derived individually for different months and times of day (month/hour-models). The forecast skill of the month/hour-models largely depends on

  18. Comparing daily temperature averaging methods: the role of surface and atmosphere variables in determining spatial and seasonal variability

    Science.gov (United States)

    Bernhardt, Jase; Carleton, Andrew M.

    2018-05-01

    The two main methods for determining the average daily near-surface air temperature, twice-daily averaging (i.e., [Tmax+Tmin]/2) and hourly averaging (i.e., the average of 24 hourly temperature measurements), typically show differences associated with the asymmetry of the daily temperature curve. To quantify the relative influence of several land surface and atmosphere variables on the two temperature averaging methods, we correlate data for 215 weather stations across the Contiguous United States (CONUS) for the period 1981-2010 with the differences between the two temperature-averaging methods. The variables are land use-land cover (LULC) type, soil moisture, snow cover, cloud cover, atmospheric moisture (i.e., specific humidity, dew point temperature), and precipitation. Multiple linear regression models explain the spatial and monthly variations in the difference between the two temperature-averaging methods. We find statistically significant correlations between both the land surface and atmosphere variables studied with the difference between temperature-averaging methods, especially for the extreme (i.e., summer, winter) seasons (adjusted R2 > 0.50). Models considering stations with certain LULC types, particularly forest and developed land, have adjusted R2 values > 0.70, indicating that both surface and atmosphere variables control the daily temperature curve and its asymmetry. This study improves our understanding of the role of surface and near-surface conditions in modifying thermal climates of the CONUS for a wide range of environments, and their likely importance as anthropogenic forcings—notably LULC changes and greenhouse gas emissions—continues.

  19. Long-term temperature trends and variability on Spitsbergen: the extended Svalbard Airport temperature series, 1898–2012

    Directory of Open Access Journals (Sweden)

    Øyvind Nordli

    2014-01-01

    Full Text Available One of the few long instrumental records available for the Arctic is the Svalbard Airport composite series that hitherto began in 1911, with observations made on Spitsbergen, the largest island in the Svalbard Archipelago. This record has now been extended to 1898 with the inclusion of observations made by hunting and scientific expeditions. Temperature has been observed almost continuously in Svalbard since 1898, although at different sites. It has therefore been possible to create one composite series for Svalbard Airport covering the period 1898–2012, and this valuable new record is presented here. The series reveals large temperature variability on Spitsbergen, with the early 20th century warming as one striking feature: an abrupt change from the cold 1910s to the local maxima of the 1930s and 1950s. With the inclusion of the new data it is possible to show that the 1910s were colder than the years at the start of the series. From the 1960s, temperatures have increased, so the present temperature level is significantly higher than at any earlier period in the instrumental history. For the entire period, and for all seasons, there are positive, statistically significant trends. Regarding the annual mean, the total trend is 2.6°C/century, whereas the largest trend is in spring, at 3.9°C/century. In Europe, it is the Svalbard Archipelago that has experienced the greatest temperature increase during the latest three decades. The composite series may be downloaded from the home page of the Norwegian Meteorological Institute and should be used with reference to the present article.

  20. Climate change and water table fluctuation: Implications for raised bog surface variability

    Science.gov (United States)

    Taminskas, Julius; Linkevičienė, Rita; Šimanauskienė, Rasa; Jukna, Laurynas; Kibirkštis, Gintautas; Tamkevičiūtė, Marija

    2018-03-01

    Cyclic peatland surface variability is influenced by hydrological conditions that highly depend on climate and/or anthropogenic activities. A low water level leads to a decrease of peatland surface and an increase of C emissions into the atmosphere, whereas a high water level leads to an increase of peatland surface and carbon sequestration in peatlands. The main aim of this article is to evaluate the influence of hydrometeorological conditions toward the peatland surface and its feedback toward the water regime. A regional survey of the raised bog water table fluctuation and surface variability was made in one of the largest peatlands in Lithuania. Two appropriate indicators for different peatland surface variability periods (increase and decrease) were detected. The first one is an 200 mm y- 1 average net rainfall over a three-year range. The second one is an average annual water depth of 25-30 cm. The application of these indicators enabled the reconstruction of Čepkeliai peatland surface variability during a 100 year period. Processes of peatland surface variability differ in time and in separate parts of peatland. Therefore, internal subbasins in peatland are formed. Subbasins involve autogenic processes that can later affect their internal hydrology, nutrient status, and vegetation succession. Internal hydrological conditions, surface fluctuation, and vegetation succession in peatland subbasins should be taken into account during evaluation of their state, nature management projects, and other peatland research works.

  1. Using dual response surfaces to reduce variability in launch vehicle design: A case study

    International Nuclear Information System (INIS)

    Yeniay, Ozgur; Unal, Resit; Lepsch, Roger A.

    2006-01-01

    Space transportation system conceptual design is a multidisciplinary process containing considerable element of risk. Uncertainties from one engineering discipline may propagate to another through linking parameters and the final system output may have an accumulation of risk. This may lead to significant deviations from expected performance. An estimate of variability or design risk therefore becomes essential for a robust design. This study utilizes the dual response surface approach to quantify variability in critical performance characteristics during conceptual design phase of a launch vehicle. Using design of experiments methods and disciplinary design analysis codes, dual response surfaces are constructed for the mean and standard deviation to quantify variability in vehicle weight and sizing analysis. Next, an optimum solution is sought to minimize variability subject to a constraint on mean weight. In this application, the dual response surface approach lead to quantifying and minimizing variability without much increase in design effort

  2. Sea surface temperature variability over North Indian Ocean - A study of two contrasting monsoon seasons

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Sathyendranath, S.; Viswambharan, N.K.; Rao, L.V.G.

    Using the satellite derived sea surface temperature (SST) data for 1979 (bad monsoon) and 1983 (good monsoon), the SST variability for two contrasting monsoon seasons is studied. The study indicates that large negative anomalies off the Somali...

  3. Tropical sea surface temperature variability near the Oligocene - Miocene boundary

    Science.gov (United States)

    Zhang, Y.; Pagani, M.

    2010-12-01

    The Oligocene/Miocene (O-M) boundary is characterized by a period of rapid and intense glaciation labeled Mi-1 at ~ 23.1 Ma. An abrupt 1.5‰ increase in the benthic foraminifera oxygen isotope composition that characterizes Mi-1 may indicate a (1) significant deep-water temperature decrease; (2) major ice-sheet expansion, or the combination of both. Current coarse Mg/Ca-based temperature estimations for the early Miocene suggests that deep-ocean temperatures were ~2°C warmer than Today [1, 2]. However, Mg/Ca based temperatures can also be influenced by changes in the carbonate ion concentration, vital effects, and diagenesis. In particular, recent evidence from mid-ocean ridge flank carbonate veins shows dramatic seawater Mg/Ca ratio changes during the Neogene (Mg/Ca from ~2.2 to 5.3, [3]), which further challenges the application of Mg/Ca thermometry. Owing to poor temperature constraints, current ice volume estimations for the late Oligocene/early Miocene range from 125% of the present-day East Antarctic Ice Sheet (EAIS) to a nearly complete collapse of the Antarctic glaciers [4]. Here we present tropical sea surface temperatures (SSTs) records based on TEX86 and alkenone UK37 near the O-M boundary. Sediment samples from Ocean Drilling Program (ODP) Site 926 in the Ceara Rise (tropical Atlantic) and Site 1148 in the South China Sea (tropical Pacific) were subject to lipid extraction, separation, gas chromatography, and liquid chromatography-mass spectrometry analysis. TEX86-based SST indicates that the tropics were ~3-4°C warmer than today and relatively stable during Mi-1. This suggests that ice-sheet dynamics, rather than temperature, might be responsible for the observed oxygen isotope changes during the O-M boundary. Further, O-M boundary averaged temperatures recorded at site 926 is ~ 0.5°C higher relative to the late Eocene from site 925 (a nearby site [5]). Given late Oligocene benthic δ18O that suggests at least 1‰ enrichment relative to the late

  4. Outlining precision boundaries among areas with different variability standards using magnetic susceptibility and geomorphic surfaces

    OpenAIRE

    Matias,Sammy S. R.; Marques Júnior,José; Siqueira,Diego S.; Pereira,Gener T.

    2014-01-01

    There is an increasing demand for detailed maps that represent in a simplified way the knowledge of the variability of a particular area or region maps. The objective was to outline precision boundaries among areas with different accuracy variability standards using magnetic susceptibility and geomorphic surfaces. The study was conducted in an area of 110 ha, which identified three compartment landscapes based on the geomorphic surfaces model. To determinate pH, organic matter, phosphorus, po...

  5. Summer U.S. Surface Air Temperature Variability: Controlling Factors and AMIP Simulation Biases

    Science.gov (United States)

    Merrifield, A.; Xie, S. P.

    2016-02-01

    This study documents and investigates biases in simulating summer surface air temperature (SAT) variability over the continental U.S. in the Coupled Model Intercomparison Project (CMIP5) Atmospheric Model Intercomparison Project (AMIP). Empirical orthogonal function (EOF) and multivariate regression analyses are used to assess the relative importance of circulation and the land surface feedback at setting summer SAT over a 30-year period (1979-2008). In observations, regions of high SAT variability are closely associated with midtropospheric highs and subsidence, consistent with adiabatic theory (Meehl and Tebaldi 2004, Lau and Nath 2012). Preliminary analysis shows the majority of the AMIP models feature high SAT variability over the central U.S., displaced south and/or west of observed centers of action (COAs). SAT COAs in models tend to be concomitant with regions of high sensible heat flux variability, suggesting an excessive land surface feedback in these models modulate U.S. summer SAT. Additionally, tropical sea surface temperatures (SSTs) play a role in forcing the leading EOF mode for summer SAT, in concert with internal atmospheric variability. There is evidence that models respond to different SST patterns than observed. Addressing issues with the bulk land surface feedback and the SST-forced component of atmospheric variability may be key to improving model skill in simulating summer SAT variability over the U.S.

  6. Sulfhydryl variable-5 extended spectrum β-lactamase in nosocomial enteric bacteria causing sepsis in mexican children

    Directory of Open Access Journals (Sweden)

    Angélica Flores-Pérez

    2015-10-01

    Full Text Available Introduction: Enteric bacteria causing nosocomial infections are often resistant to third-generation cephalosporins due to the production of extended-spectrum β-lactamases (ESBLs. Objective: To describe and characterize the ESBLs pattern present in Klebsiella pneumoniae and Serratia marcescens strains, isolated as causative of nosocomial sepsis in pediatric patients at Instituto Nacional de Pediatría (National Institute of Pediatrics. Material and methods: We analyzed 94 strains of K. pneumoniae and 7 of S. marcescens isolated from clinical specimens from 2002-2005, causative of sepsis in a children’s hospital. We evaluated antibiotic susceptibility and detection of ESBL phenotypes by disk diffusion methods; ceftazidime-resistant isolates were further characterized by pulsed field gel electrophoresis (PFGE; and ESBLs were phenotypically and genotypically characterized by isoelectric focusing, polymerase chain reaction (PCR and sequencing. We also assed for presence of conjugative plasmids bearing the ESBL gene. Results: 51/94 (54% of K. pneumoniae isolates, and 5/7 (71% of S. marcescens isolates were resistant to ceftazidime; all carried a blaSHV-5 gene. All K. pneumoniae isolates had a distinct PFGE profile, yet all carried a ~48-Kb plasmid, that was conjugatively transferable to an Escherichia coli receptor, which expressed the resistance phenotype. On the other hand, all S. marcescens isolates had a similar PFGE profile, were unable to transfer the ceftazidime-resistance phenotype, and were isolated from the same ward in a short time-span suggesting an outbreak. Conclusions: The overall prevalence of ESBL-producing enteric bacteria in this hospital is high but similar to other Latin American reports. The sulfhydryl variable-5 (SHV-5 ESBL gene appears to reside in a highly mobile plasmid, capable of spreading among different K. pneumoniae clones and perhaps even to S. marcescens.

  7. Monitoring the variability of sea level and surface circulation with satellite altimetry

    NARCIS (Netherlands)

    Volkov, Denis L. "Jr"

    2004-01-01

    Variability in the ocean plays an important role in determining global weather and climate conditions. The advent of satellite altimetry has significantly facilitated the study of the variability of sea level and surface circulation. Satellites provide high-quality regular and nearly global

  8. Future climate warming increases Greenland ice sheet surface mass balance variability

    NARCIS (Netherlands)

    Fyke, J.G.; Vizcaino, M.; Lipscomb, W.; Price, S.

    2014-01-01

    The integrated surface mass balance (SMB) of the Greenland ice sheet (GrIS) has large interannual variability. Long-term future changes to this variability will affect GrIS dynamics, freshwater fluxes, regional oceanography, and detection of changes in ice volume trends. Here we analyze a simulated

  9. Sea Surface Temperature and Ocean Color Variability in the South China Sea

    Science.gov (United States)

    Conaty, A. P.

    2001-12-01

    The South China Sea is a marginal sea in the Southeast Asian region whose surface circulation is driven by monsoons and whose surface currents have complex seasonal patterns. Its rich natural resources and strategic location have made its small islands areas of political dispute among the neighboring nations. This study aims to show the seasonal and interannual variability of sea surface temperature and ocean color in South China Sea. It makes use of NOAA's Advanced Very High Resolution Radiometer (AVHRR) satellite data sets on sea surface temperature for the period 1981-2000 and NASA's Nimbus-7 Coastal Zone Color Scanner (CZCS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite data sets on pigment concentration (ocean color) for the period 1981-1996 and 1997-2000, respectively. Transect lines were drawn along several potential hotspot areas to show the variability in sea surface temperature and pigment concentration through time. In-situ data on sea surface temperature along South China Sea were likewise plotted to see the variability with time. Higher seasonal variability in sea surface temperature was seen at higher latitudes. Interannual variability was within 1-3 Kelvin. In most areas, pigment concentration was higher during northern hemisphere winter and autumn, after the monsoon rains, with a maximum of 30 milligrams per cubic meter.

  10. Long-range attractive forces extending from the alumina’s nanolayer surface in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Leonid A. Kaledin

    2015-07-01

    Full Text Available Aluminum oxide-hydroxide nanolayer with a thickness of approximately 1.2 nm is electroadhesively deposited onto silicious support material with large surface area of about 50 m2/g, forming a highly electropositive composite of boehmite nanolayer in the form of monocrystalline oxide/hydroxide (α-Al2O3·H2O on the second electronegative solid. The composite can be viewed as a sphere with a rough surface and charge density of approximately 0.08 C/m2. This creates a significant electric field with negligible screening (ka ≪ 1 in the region close to the surface of the nanocomposite. This field attracts nano- and micron-sized particles from as far as 200 μm in a few seconds, many orders of magnitude greater than conventional Derjaguin–Landau–Verwey–Overbeek (DLVO theory, which predicts only nanometer-scale effects arising from the presence of the surface. The strong electric field on the surface is then able to retain small particles such as viruses, atomically thin sheets of graphene oxide, RNA, DNA, proteins, dyes as well as heavy metals such as cobalt, arsenic, and lead. Alumina’s nanolayer surface can be further functionalized by adding other sub-micron or nano-sized particles to target a specific contaminant. An example is shown where alumina nanolayer is coated with nano-sized iron monohydrate to yield an arsenic sorbent that shows high sorption capacity.

  11. Extended-range high-resolution dynamical downscaling over a continental-scale spatial domain with atmospheric and surface nudging

    Science.gov (United States)

    Husain, S. Z.; Separovic, L.; Yu, W.; Fernig, D.

    2014-12-01

    Extended-range high-resolution mesoscale simulations with limited-area atmospheric models when applied to downscale regional analysis fields over large spatial domains can provide valuable information for many applications including the weather-dependent renewable energy industry. Long-term simulations over a continental-scale spatial domain, however, require mechanisms to control the large-scale deviations in the high-resolution simulated fields from the coarse-resolution driving fields. As enforcement of the lateral boundary conditions is insufficient to restrict such deviations, large scales in the simulated high-resolution meteorological fields are therefore spectrally nudged toward the driving fields. Different spectral nudging approaches, including the appropriate nudging length scales as well as the vertical profiles and temporal relaxations for nudging, have been investigated to propose an optimal nudging strategy. Impacts of time-varying nudging and generation of hourly analysis estimates are explored to circumvent problems arising from the coarse temporal resolution of the regional analysis fields. Although controlling the evolution of the atmospheric large scales generally improves the outputs of high-resolution mesoscale simulations within the surface layer, the prognostically evolving surface fields can nevertheless deviate from their expected values leading to significant inaccuracies in the predicted surface layer meteorology. A forcing strategy based on grid nudging of the different surface fields, including surface temperature, soil moisture, and snow conditions, toward their expected values obtained from a high-resolution offline surface scheme is therefore proposed to limit any considerable deviation. Finally, wind speed and temperature at wind turbine hub height predicted by different spectrally nudged extended-range simulations are compared against observations to demonstrate possible improvements achievable using higher spatiotemporal

  12. Seasonal variability of the Red Sea, from GRACE time-variable gravity and altimeter sea surface height measurements

    Science.gov (United States)

    Wahr, John; Smeed, David; Leuliette, Eric; Swenson, Sean

    2014-05-01

    Seasonal variability of sea surface height and mass within the Red Sea, occurs mostly through the exchange of heat with the atmosphere and wind-driven inflow and outflow of water through the strait of Bab el Mandab that opens into the Gulf of Aden to the south. The seasonal effects of precipitation and evaporation, of water exchange through the Suez Canal to the north, and of runoff from the adjacent land, are all small. The flow through the Bab el Mandab involves a net mass transfer into the Red Sea during the winter and a net transfer out during the summer. But that flow has a multi-layer pattern, so that in the summer there is actually an influx of cool water at intermediate (~100 m) depths. Thus, summer water in the southern Red Sea is warmer near the surface due to higher air temperatures, but cooler at intermediate depths (especially in the far south). Summer water in the northern Red Sea experiences warming by air-sea exchange only. The temperature profile affects the water density, which impacts the sea surface height but has no effect on vertically integrated mass. Here, we study this seasonal cycle by combining GRACE time-variable mass estimates, altimeter (Jason-1, Jason-2, and Envisat) measurements of sea surface height, and steric sea surface height contributions derived from depth-dependent, climatological values of temperature and salinity obtained from the World Ocean Atlas. We find good consistency, particularly in the northern Red Sea, between these three data types. Among the general characteristics of our results are: (1) the mass contributions to seasonal SSHT variations are much larger than the steric contributions; (2) the mass signal is largest in winter, consistent with winds pushing water into the Red Sea through the Strait of Bab el Mandab in winter, and out during the summer; and (3) the steric signal is largest in summer, consistent with summer sea surface warming.

  13. Diurnal variability of surface fluxes at an oceanic station in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, Y.V.B.; Rao, D.P.

    Diurnal variability of the surface fluxes and ocean heat content was studied using the time-series data on marine surface meteorological parameters and upper ocean temperature collected at an oceanic station in the Bay of Bengal during 1st to 8th...

  14. Variability in soil CO2 production and surface CO2 efflux across riparian-hillslope transitions

    Science.gov (United States)

    Vincent Jerald. Pacific

    2007-01-01

    The spatial and temporal controls on soil CO2 production and surface CO2 efflux have been identified as an outstanding gap in our understanding of carbon cycling. I investigated both the spatial and temporal variability of soil CO2 concentrations and surface CO2 efflux across eight topographically distinct riparian-hillslope transitions in the ~300 ha subalpine upper-...

  15. Two-Layer Variable Infiltration Capacity Land Surface Representation for General Circulation Models

    Science.gov (United States)

    Xu, L.

    1994-01-01

    A simple two-layer variable infiltration capacity (VIC-2L) land surface model suitable for incorporation in general circulation models (GCMs) is described. The model consists of a two-layer characterization of the soil within a GCM grid cell, and uses an aerodynamic representation of latent and sensible heat fluxes at the land surface. The effects of GCM spatial subgrid variability of soil moisture and a hydrologically realistic runoff mechanism are represented in the soil layers. The model was tested using long-term hydrologic and climatalogical data for Kings Creek, Kansas to estimate and validate the hydrological parameters. Surface flux data from three First International Satellite Land Surface Climatology Project Field Experiments (FIFE) intensive field compaigns in the summer and fall of 1987 in central Kansas, and from the Anglo-Brazilian Amazonian Climate Observation Study (ABRACOS) in Brazil were used to validate the mode-simulated surface energy fluxes and surface temperature.

  16. Rainfall variability and its influence on surface flow regimes. Examples from the central highlands of Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Osman, M. [Debre Zeit (Ethiopia); Sauerborn, P. [Seminar fuer Geographie und ihre Didaktik, Univ. zu Koeln, Koeln (Germany)

    2002-07-01

    The article shows results of an international and interdisciplinary project with the title 'Rainfall and its Erosivity in Ethiopia'. Rainfall variability affects the water resource management of Ethiopia. The influence of rainfall variability on flow regimes was investigated using five gauging stations with data availability from 1982-1997. It was confirmed that the variability in rainfall has a direct implication for surface runoff. Surface runoff declined at most of the gauging stations investigated. Therefore, effective water resource management is recommended for the study area. Future research should focus on watershed management which includes land-use and land cover. The question posed here is whether the variability in rainfall significantly affected surface flow in the study area. (orig.)

  17. Surface geometry of BaO on W(100): A surface-extended x-ray-absorption fine-structure study

    International Nuclear Information System (INIS)

    Shih, A.; Hor, C.; Elam, W.; Kirkland, J.; Mueller, D.

    1991-01-01

    A surface-extended x-ray-absorption fine-structure study of ordered monolayers of coadsorbed barium and oxygen on a single-crystal W(100) surface is described. A (√2 x √2 )R45 degree structure with a stoichiometric barium-to-oxygen ratio, and a (2 √2 x √2 )R45 degree structure with a nearly 1:2 barium-to-oxygen atomic ratio both form on W(100). The surface-extended x-ray-absorption fine-structure results indicate that all the barium and oxygen atoms are nearly coplanar in the (√2 x √2 )R45 degree overlayer. The Ba-to-O distance in this overlayer is 3.20 ±0.05 A and β=82 degree ±5 degree, where β is the angle between the Ba-O internuclear axis and the surface normal. For the (2 √2 x √2 )R45 degree overlayer, there are two types of oxygen sites. Oxygen atoms nearly coplanar with the barium atoms are also present in these films with a Ba-to-O distance of 3.27±0.05 A and β=75±4 degree. Additional oxygen atoms lie outside the barium plane at a distance 2.03±0.05 A and β=23±10 degree from the nearest barium atoms

  18. Basin-scale heterogeneity in Antarctic precipitation and its impact on surface mass variability

    Directory of Open Access Journals (Sweden)

    J. Fyke

    2017-11-01

    Full Text Available Annually averaged precipitation in the form of snow, the dominant term of the Antarctic Ice Sheet surface mass balance, displays large spatial and temporal variability. Here we present an analysis of spatial patterns of regional Antarctic precipitation variability and their impact on integrated Antarctic surface mass balance variability simulated as part of a preindustrial 1800-year global, fully coupled Community Earth System Model simulation. Correlation and composite analyses based on this output allow for a robust exploration of Antarctic precipitation variability. We identify statistically significant relationships between precipitation patterns across Antarctica that are corroborated by climate reanalyses, regional modeling and ice core records. These patterns are driven by variability in large-scale atmospheric moisture transport, which itself is characterized by decadal- to centennial-scale oscillations around the long-term mean. We suggest that this heterogeneity in Antarctic precipitation variability has a dampening effect on overall Antarctic surface mass balance variability, with implications for regulation of Antarctic-sourced sea level variability, detection of an emergent anthropogenic signal in Antarctic mass trends and identification of Antarctic mass loss accelerations.

  19. Extended survival of several organisms and amino acids under simulated martian surface conditions

    Science.gov (United States)

    Johnson, A. P.; Pratt, L. M.; Vishnivetskaya, T.; Pfiffner, S.; Bryan, R. A.; Dadachova, E.; Whyte, L.; Radtke, K.; Chan, E.; Tronick, S.; Borgonie, G.; Mancinelli, R. L.; Rothschild, L. J.; Rogoff, D. A.; Horikawa, D. D.; Onstott, T. C.

    2011-02-01

    Recent orbital and landed missions have provided substantial evidence for ancient liquid water on the martian surface as well as evidence of more recent sedimentary deposits formed by water and/or ice. These observations raise serious questions regarding an independent origin and evolution of life on Mars. Future missions seek to identify signs of extinct martian biota in the form of biomarkers or morphological characteristics, but the inherent danger of spacecraft-borne terrestrial life makes the possibility of forward contamination a serious threat not only to the life detection experiments, but also to any extant martian ecosystem. A variety of cold and desiccation-tolerant organisms were exposed to 40 days of simulated martian surface conditions while embedded within several centimeters of regolith simulant in order to ascertain the plausibility of such organisms' survival as a function of environmental parameters and burial depth. Relevant amino acid biomarkers associated with terrestrial life were also analyzed in order to understand the feasibility of detecting chemical evidence for previous biological activity. Results indicate that stresses due to desiccation and oxidation were the primary deterrent to organism survival, and that the effects of UV-associated damage, diurnal temperature variations, and reactive atmospheric species were minimal. Organisms with resistance to desiccation and radiation environments showed increased levels of survival after the experiment compared to organisms characterized as psychrotolerant. Amino acid analysis indicated the presence of an oxidation mechanism that migrated downward through the samples during the course of the experiment and likely represents the formation of various oxidizing species at mineral surfaces as water vapor diffused through the regolith. Current sterilization protocols may specifically select for organisms best adapted to survival at the martian surface, namely species that show tolerance to radical

  20. Angular scanning and variable wavelength surface plasmon resonance allowing free sensor surface selection for optimum material- and bio-sensing

    NARCIS (Netherlands)

    Lakayan, Dina; Tuppurainen, Jussipekka; Albers, Martin; van Lint, Matthijs J.; van Iperen, Dick J.; Weda, Jelmer J.A.; Kuncova-Kallio, Johana; Somsen, Govert W.; Kool, Jeroen

    2018-01-01

    A variable-wavelength Kretschmann configuration surface plasmon resonance (SPR) apparatus with angle scanning is presented. The setup provides the possibility of selecting the optimum wavelength with respect to the properties of the metal layer of the sensorchip, sample matrix, and biomolecular

  1. Evolution of the Novalux extended cavity surface-emitting semiconductor laser (NECSEL)

    Science.gov (United States)

    McInerney, John G.

    2016-03-01

    Novalux Inc was an enterprise founded by Aram Mooradian in 1998 to commercialise a novel electrically pumped vertical extended cavity semiconductor laser platform, initially aiming to produce pump lasers for optical fiber telecommunication networks. Following successful major investment in 2000, the company developed a range of single- and multi-mode 980 nm pump lasers emitting from 100-500 mW with excellent beam quality and efficiency. This rapid development required solution of several significant problems in chip and external cavity design, substrate and DBR mirror optimization, thermal engineering and mode selection. Output coupling to single mode fiber was exceptional. Following the collapse of the long haul telecom market in late 2001, a major reorientation of effort was undertaken, initially to develop compact 60-100 mW hybrid monolithically integrated pumplets for metro/local amplified networks, then to frequency-doubled blue light emitters for biotech, reprographics and general scientific applications. During 2001-3 I worked at Novalux on a career break from University College Cork, first as R&D Director managing a small group tasked with producing new capabilities and product options based on the NECSEL platform, including high power, pulsed and frequency doubled versions, then in 2002 as Director of New Product Realization managing the full engineering team, leading the transition to frequency doubled products.

  2. Adhesion of nano-sized particles to the surface of bacteria: mechanistic study with the extended DLVO theory.

    Science.gov (United States)

    Hwang, Geelsu; Ahn, Ik-Sung; Mhin, Byung Jin; Kim, Ju-Young

    2012-09-01

    Due to the increasing production and application of nanoparticles, their release into the environment would be inevitable, which requires a better understanding of their fate in the environment. When considering their toxic behavior or biodegradation as their fate, their adhesion to the cell surface must be the first step to be thoroughly studied. In this study, nano-sized polymeric particles of urethane acrylate with various hydrophobicity and ionic properties were synthesized as model nanoparticles, and their adhesion to Pseudomonas putida strains was monitored. The higher hydrophobicity and positive charge density on the particle surface exhibited the larger adhesion to the bacteria, whereas negative charge density on the particle hindered their adhesion to the bacteria, albeit high hydrophobicity of particle. These observations were successfully explained with the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Surface-temperature trends and variability in the low-latitude North Atlantic since 1552

    KAUST Repository

    Saenger, Casey; Cohen, Anne L.; Oppo, Delia W.; Halley, Robert B.; Carilli, Jessica E.

    2009-01-01

    Sea surface temperature variability in the North Atlantic Ocean recorded since about 1850 has been ascribed to a natural multidecadal oscillation superimposed on a background warming trend1-6. It has been suggested that the multidecadal variability may be a persistent feature6-8, raising the possibility that the associated climate impacts may be predictable7,8. owever, our understanding of the multidecadal ocean variability before the instrumental record is based on interpretations of high-latitude terrestrial proxy records. Here we present an absolutely dated and annually resolved record of sea surface temperature from the Bahamas, based on a 440-year time series of coral growth rates. The reconstruction indicates that temperatures were as warm as today from about 1552 to 1570, then cooled by about 1° C from 1650 to 1730 before warming until the present. Our estimates of background variability suggest that much of the warming since 1900 was driven by anthropogenic forcing. Interdecadal variability with a period of 15-25 years is superimposed on most of the record, but multidecadal variability becomes significant only after 1730. We conclude that the multidecadal variability in sea surface temperatures in the low-latitude western Atlantic Ocean may not be persistent, potentially making accurate decadal climate forecasts more difficult to achieve. © 2009 Macmillan Publishers Limited. All rights reserved.

  4. Surface-temperature trends and variability in the low-latitude North Atlantic since 1552

    KAUST Repository

    Saenger, Casey

    2009-06-21

    Sea surface temperature variability in the North Atlantic Ocean recorded since about 1850 has been ascribed to a natural multidecadal oscillation superimposed on a background warming trend1-6. It has been suggested that the multidecadal variability may be a persistent feature6-8, raising the possibility that the associated climate impacts may be predictable7,8. owever, our understanding of the multidecadal ocean variability before the instrumental record is based on interpretations of high-latitude terrestrial proxy records. Here we present an absolutely dated and annually resolved record of sea surface temperature from the Bahamas, based on a 440-year time series of coral growth rates. The reconstruction indicates that temperatures were as warm as today from about 1552 to 1570, then cooled by about 1° C from 1650 to 1730 before warming until the present. Our estimates of background variability suggest that much of the warming since 1900 was driven by anthropogenic forcing. Interdecadal variability with a period of 15-25 years is superimposed on most of the record, but multidecadal variability becomes significant only after 1730. We conclude that the multidecadal variability in sea surface temperatures in the low-latitude western Atlantic Ocean may not be persistent, potentially making accurate decadal climate forecasts more difficult to achieve. © 2009 Macmillan Publishers Limited. All rights reserved.

  5. Extending and refining the nuclear mass surface with ISOLTRAP and MISTRAL

    CERN Document Server

    Lunney, M D

    2000-01-01

    Through the nuclear binding energy the atomic mass gives us important information about nuclear structure. Viewing the ensemble of mass data over the nuclear chart, we can examine the hills and valleys that form this surface and make hypotheses about the effects of certain nuclear configurations. To unveil these effects, mass measurements of very high precision (10$^{-6}$) are required. Two experiments at ISOLDE pursue this effort of nuclear cartography the tandem Penning trap spectrometer ISOLTRAP and the radiofrequency transmission spectrometer MISTRAL. Between them, the masses of almost 150 nuclides have been measured from stable isotopes to those with half-lives as short as 30 ms. Both experiments rely on good optical properties of a low energy ion beam and are thus well suited to the ISOLDE facility. (30 refs).

  6. Understanding surface-water availability in the Central Valley as a means to projecting future groundwater storage with climate variability

    Science.gov (United States)

    Goodrich, J. P.; Cayan, D. R.

    2017-12-01

    California's Central Valley (CV) relies heavily on diverted surface water and groundwater pumping to supply irrigated agriculture. However, understanding the spatiotemporal character of water availability in the CV is difficult because of the number of individual farms and local, state, and federal agencies involved in using and managing water. Here we use the Central Valley Hydrologic Model (CVHM), developed by the USGS, to understand the relationships between climatic variability, surface water inputs, and resulting groundwater use over the historical period 1970-2013. We analyzed monthly surface water diversion data from >500 CV locations. Principle components analyses were applied to drivers constructed from meteorological data, surface reservoir storage, ET, land use cover, and upstream inflows, to feed multiple regressions and identify factors most important in predicting surface water diversions. Two thirds of the diversion locations ( 80% of total diverted water) can be predicted to within 15%. Along with monthly inputs, representations of cumulative precipitation over the previous 3 to 36 months can explain an additional 10% of variance, depending on location, compared to results that excluded this information. Diversions in the southern CV are highly sensitive to inter-annual variability in precipitation (R2 = 0.8), whereby more surface water is used during wet years. Until recently, this was not the case in the northern and mid-CV, where diversions were relatively constant annually, suggesting relative insensitivity to drought. In contrast, this has important implications for drought response in southern regions (eg. Tulare Basin) where extended dry conditions can severely limit surface water supplies and lead to excess groundwater pumping, storage loss, and subsidence. In addition to fueling our understanding of spatiotemporal variability in diversions, our ability to predict these water balance components allows us to update CVHM predictions before

  7. Surface quality and topographic inspection of variable compliance part after precise turning

    Science.gov (United States)

    Nieslony, P.; Krolczyk, G. M.; Wojciechowski, S.; Chudy, R.; Zak, K.; Maruda, R. W.

    2018-03-01

    The paper presents the problem of precise turning of the mould parts with variable compliance and demonstrates a topographic inspection of the machined surface quality. The study was conducted for the cutting tools made of cemented carbide with coatings, in a range of variable cutting parameters. The long shaft with special axial hole, made of hardened 55NiCrMoV6 steel was selected as a workpiece. The carried out study included the stiffness measurement of the machining system, as well as the investigation of cutting force components. In this context, the surface topography parameters were evaluated using the stylus profile meter and analysed. The research revealed that the surface topography, alongside the 3D functional parameters, and PSD influences the performance of the machined surface. The lowest surface roughness parameters values, equalled to Sa = 1 μm and Sz = 4.3 μm have been obtained during turning with cutting speed vc = 90 m/min. The stable turning of variable compliance part affects the surface texture formation with a unidirectional perpendicular, anisotropic structure. Nevertheless, in case of unstable turning, the characteristic chatter marks are observed, and process dynamics has greater contribution in formation of surface finish than turning kinematics and elastic plastic deformation of workpiece.

  8. Extended averaging phase-shift schemes for Fizeau interferometry on high-numerical-aperture spherical surfaces

    Science.gov (United States)

    Burke, Jan

    2010-08-01

    Phase-shifting Fizeau interferometry on spherical surfaces is impaired by phase-shift errors increasing with the numerical aperture, unless a custom optical set-up or wavelength shifting is used. This poses a problem especially for larger numerical apertures, and requires good error tolerance of the phase-shift method used; but it also constitutes a useful testing facility for phase-shift formulae, because a vast range of phase-shift intervals can be tested in a single measurement. In this paper I show how the "characteristic polynomials" method can be used to generate a phase-shifting method for the actual numerical aperture, and analyse residual cyclical phase errors by comparing a phase map from an interferogram with a few fringes to a phase mpa from a nulled fringe. Unrelated to the phase-shift miscalibration, thirdharmonic error fringes are found. These can be dealt with by changing the nominal phase shift from 90°/step to 60°/step and re-tailoring the evaluation formula for third-harmonic rejection. The residual error has the same frequency as the phase-shift signal itself, and can be removed by averaging measurements. Some interesting features of the characteristic polynomials for the averaged formulae emerge, which also shed some light on the mechanism that generates cyclical phase errors.

  9. Formation of macroscopic surface layers on Fe(0) electrocoagulation electrodes during an extended field trial of arsenic treatment.

    Science.gov (United States)

    van Genuchten, Case M; Bandaru, Siva R S; Surorova, Elena; Amrose, Susan E; Gadgil, Ashok J; Peña, Jasquelin

    2016-06-01

    Extended field trials to remove arsenic (As) via Fe(0) electrocoagulation (EC) have demonstrated consistent As removal from groundwater to concentrations below 10 μg L(-1). However, the coulombic performance of long-term EC field operation is lower than that of laboratory-based systems. Although EC electrodes used over prolonged periods show distinct passivation layers, which have been linked to decreased treatment efficiency, the spatial distribution and mineralogy of such surface layers have not been investigated. In this work, we combine wet chemical measurements with sub-micron-scale chemical maps and selected area electron diffraction (SAED) to determine the chemical composition and mineral phase of surface layers formed during long-term Fe(0) EC treatment. We analyzed Fe(0) EC electrodes used for 3.5 months of daily treatment of As-contaminated groundwater in rural West Bengal, India. We found that the several mm thick layer that formed on cathodes and anodes consisted of primarily magnetite, with minor fractions of goethite. Spatially-resolved SAED patterns also revealed small quantities of CaCO3, Mn oxides, and SiO2, the source of which was the groundwater electrolyte. We propose that the formation of the surface layer contributes to decreased treatment performance by preventing the migration of EC-generated Fe(II) to the bulk electrolyte, where As removal occurs. The trapped Fe(II) subsequently increases the surface layer size at the expense of treatment efficiency. Based on these findings, we discuss several simple and affordable methods to prevent the efficiency loss due to the surface layer, including alternating polarity cycles and cleaning the Fe(0) surface mechanically or via electrolyte scouring. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Moving gantry method for electron beam dose profile measurement at extended source-to-surface distances.

    Science.gov (United States)

    Fekete, Gábor; Fodor, Emese; Pesznyák, Csilla

    2015-03-08

    A novel method has been put forward for very large electron beam profile measurement. With this method, absorbed dose profiles can be measured at any depth in a solid phantom for total skin electron therapy. Electron beam dose profiles were collected with two different methods. Profile measurements were performed at 0.2 and 1.2 cm depths with a parallel plate and a thimble chamber, respectively. 108cm × 108 cm and 45 cm × 45 cm projected size electron beams were scanned by vertically moving phantom and detector at 300 cm source-to-surface distance with 90° and 270° gantry angles. The profiles collected this way were used as reference. Afterwards, the phantom was fixed on the central axis and the gantry was rotated with certain angular steps. After applying correction for the different source-to-detector distances and incidence of angle, the profiles measured in the two different setups were compared. Correction formalism has been developed. The agreement between the cross profiles taken at the depth of maximum dose with the 'classical' scanning and with the new moving gantry method was better than 0.5 % in the measuring range from zero to 71.9 cm. Inverse square and attenuation corrections had to be applied. The profiles measured with the parallel plate chamber agree better than 1%, except for the penumbra region, where the maximum difference is 1.5%. With the moving gantry method, very large electron field profiles can be measured at any depth in a solid phantom with high accuracy and reproducibility and with much less time per step. No special instrumentation is needed. The method can be used for commissioning of very large electron beams for computer-assisted treatment planning, for designing beam modifiers to improve dose uniformity, and for verification of computed dose profiles.

  11. A Study on the Relationships among Surface Variables to Adjust the Height of Surface Temperature for Data Assimilation.

    Science.gov (United States)

    Kang, J. H.; Song, H. J.; Han, H. J.; Ha, J. H.

    2016-12-01

    The observation processing system, KPOP (KIAPS - Korea Institute of Atmospheric Prediction Systems - Package for Observation Processing) have developed to provide optimal observations to the data assimilation system for the KIAPS Integrated Model (KIM). Currently, the KPOP has capable of processing almost all of observations for the KMA (Korea Meteorological Administration) operational global data assimilation system. The height adjustment of SURFACE observations are essential for the quality control due to the difference in height between observation station and model topography. For the SURFACE observation, it is usual to adjust the height using lapse rate or hypsometric equation, which decides values mainly depending on the difference of height. We have a question of whether the height can be properly adjusted following to the linear or exponential relationship solely with regard to the difference of height, with disregard the atmospheric conditions. In this study, firstly we analyse the change of surface variables such as temperature (T2m), pressure (Psfc), humidity (RH2m and Q2m), and wind components (U and V) according to the height difference. Additionally, we look further into the relationships among surface variables . The difference of pressure shows a strong linear relationship with difference of height. But the difference of temperature according to the height shows a significant correlation with difference of relative humidity than with the height difference. A development of reliable model for the height-adjustment of surface temperature is being undertaken based on the preliminary results.

  12. Area-averaged surface fluxes and their time-space variability over the FIFE experimental domain

    Science.gov (United States)

    Smith, E. A.; Hsu, A. Y.; Crosson, W. L.; Field, R. T.; Fritschen, L. J.; Gurney, R. J.; Kanemasu, E. T.; Kustas, W. P.; Nie, D.; Shuttleworth, W. J.

    1992-01-01

    The underlying mean and variance properties of surface net radiation, sensible-latent heat fluxes and soil heat flux are studied over the densely instrumented grassland region encompassing FIFE. Flux variability is discussed together with the problem of scaling up to area-averaged fluxes. Results are compared and contrasted for cloudy and clear situations and examined for the influence of surface-induced biophysical controls (burn and grazing treatments) and topographic controls (aspect ratios and slope factors).

  13. Electrochemical state and internal variables estimation using a reduced-order physics-based model of a lithium-ion cell and an extended Kalman filter

    Energy Technology Data Exchange (ETDEWEB)

    Stetzel, KD; Aldrich, LL; Trimboli, MS; Plett, GL

    2015-03-15

    This paper addresses the problem of estimating the present value of electrochemical internal variables in a lithium-ion cell in real time, using readily available measurements of cell voltage, current, and temperature. The variables that can be estimated include any desired set of reaction flux and solid and electrolyte potentials and concentrations at any set of one-dimensional spatial locations, in addition to more standard quantities such as state of charge. The method uses an extended Kalman filter along with a one-dimensional physics-based reduced-order model of cell dynamics. Simulations show excellent and robust predictions having dependable error bounds for most internal variables. (C) 2014 Elsevier B.V. All rights reserved.

  14. Application of a serial extended forecast experiment using the ECMWF model to interpret the predictive skill of tropical intraseasonal variability

    Energy Technology Data Exchange (ETDEWEB)

    Agudelo, P.A.; Hoyos, C.D.; Webster, P.J.; Curry, J.A. [Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA (United States)

    2009-05-15

    The extended-range forecast skill of the ECMWF operational forecast model is evaluated during tropical intraseasonal oscillation (ISO) events in the Indo-West Pacific warm pool. The experiment consists of ensemble extended serial forecasts including winter and summer ISO cases. The forecasts are compared with the ERA-40 analyses. The analysis focuses on understanding the origin of forecast errors by studying the vertical structure of relevant dynamical and moist convective features associated with the ISO. The useful forecast time scale for circulation anomalies is in average 13 days during winter compared to 7-8 days during summer. The forecast skill is not stationary and presents evidence of a flow-dependent nature, with states of the coupled system corresponding to long-lived convective envelopes associated with the ISO for which the skill is always low regardless of the starting date of the forecast. The model is not able to forecast skillfully the generation of specific humidity anomalies and results indicate that the convective processes in the model are associated with the erosion of the ISO forecast skill in the model. Circulation-associated anomalies are forecast better than moist convective associated anomalies. The model tends to generate a more stable atmosphere, limiting the model's capability to reproduce deep convective events, resulting in smaller humidity and circulation anomalies in the forecasts compared to those in ERA-40. (orig.)

  15. Spatiotemporal variability in surface energy balance across tundra, snow and ice in Greenland

    DEFF Research Database (Denmark)

    Lund, Magnus; Stiegler, Christian; Abermann, Jakob

    2017-01-01

    The surface energy balance (SEB) is essential for understanding the coupled cryosphere–atmosphere system in the Arctic. In this study, we investigate the spatiotemporal variability in SEB across tundra, snow and ice. During the snow-free period, the main energy sink for ice sites is surface melt....... For tundra, energy is used for sensible and latent heat flux and soil heat flux leading to permafrost thaw. Longer snow-free period increases melting of the Greenland Ice Sheet and glaciers and may promote tundra permafrost thaw. During winter, clouds have a warming effect across surface types whereas during...

  16. Arctic Sea Ice Basal Melt Onset Variability and Associated Ocean Surface Heating

    Science.gov (United States)

    Merrick, R. A.; Hutchings, J. K.

    2015-12-01

    The interannual and regional variability in Arctic sea ice melt has previously been characterized only in terms of surface melting. A focus on the variability in the onset of basal melt is additionally required to understand Arctic melt patterns. Monitoring basal melt provides a glimpse into the importance of ocean heating to sea ice melt. This warming is predominantly through seawater exposure due to lead opening and the associated solar warming at the ocean's surface. We present the temporal variability in basal melt onset observed by ice mass balance buoys throughout the Arctic Ocean since 2003, providing a different perspective than the satellite microwave data used to measure the onset of surface melt. We found that melt onset varies greatly, even for buoys deployed within 100km of each other. Therefore large volumes of data are necessary to accurately estimate the variability of basal melt onset. Once the variability of basal melt onset has been identified, we can investigate how this range has been changing as a response to atmospheric and oceanic warming, changes in ice morphology as well as the intensification of the ice albedo feedback.

  17. Sea Surface Height Variability and Eddy Statistical Properties in the Red Sea

    KAUST Repository

    Zhan, Peng

    2013-01-01

    Satellite sea surface height (SSH) data over 1992-2012 are analyzed to study the spatial and temporal variability of sea level in the Red Sea. Empirical orthogonal functions (EOF) analysis suggests the remarkable seasonality of SSH in the Red Sea

  18. Light refraction in sapphire plates with a variable angle of crystal optical axis to the surface

    International Nuclear Information System (INIS)

    Vetrov, V. N.; Ignatenkov, B. A.

    2013-01-01

    The modification of sapphire by inhomogeneous plastic deformation makes it possible to obtain plates with a variable angle of inclination of the crystal optical axis to the plate surface. The refraction of light in this plate at perpendicular and oblique incidence of a parallel beam of rays is considered. The algorithm of calculating the refractive index of extraordinary ray and the birefringence is proposed.

  19. PAF: A software tool to estimate free-geometry extended bodies of anomalous pressure from surface deformation data

    Science.gov (United States)

    Camacho, A. G.; Fernández, J.; Cannavò, F.

    2018-02-01

    We present a software package to carry out inversions of surface deformation data (any combination of InSAR, GPS, and terrestrial data, e.g., EDM, levelling) as produced by 3D free-geometry extended bodies with anomalous pressure changes. The anomalous structures are described as an aggregation of elementary cells (whose effects are estimated as coming from point sources) in an elastic half space. The linear inverse problem (considering some simple regularization conditions) is solved by means of an exploratory approach. This software represents the open implementation of a previously published methodology (Camacho et al., 2011). It can be freely used with large data sets (e.g. InSAR data sets) or with data coming from small control networks (e.g. GPS monitoring data), mainly in volcanic areas, to estimate the expected pressure bodies representing magmatic intrusions. Here, the software is applied to some real test cases.

  20. Solar Irradiance Variability is Caused by the Magnetic Activity on the Solar Surface.

    Science.gov (United States)

    Yeo, Kok Leng; Solanki, Sami K; Norris, Charlotte M; Beeck, Benjamin; Unruh, Yvonne C; Krivova, Natalie A

    2017-09-01

    The variation in the radiative output of the Sun, described in terms of solar irradiance, is important to climatology. A common assumption is that solar irradiance variability is driven by its surface magnetism. Verifying this assumption has, however, been hampered by the fact that models of solar irradiance variability based on solar surface magnetism have to be calibrated to observed variability. Making use of realistic three-dimensional magnetohydrodynamic simulations of the solar atmosphere and state-of-the-art solar magnetograms from the Solar Dynamics Observatory, we present a model of total solar irradiance (TSI) that does not require any such calibration. In doing so, the modeled irradiance variability is entirely independent of the observational record. (The absolute level is calibrated to the TSI record from the Total Irradiance Monitor.) The model replicates 95% of the observed variability between April 2010 and July 2016, leaving little scope for alternative drivers of solar irradiance variability at least over the time scales examined (days to years).

  1. Test-retest reliability of trunk motor variability measured by large-array surface electromyography.

    Science.gov (United States)

    Abboud, Jacques; Nougarou, François; Loranger, Michel; Descarreaux, Martin

    2015-01-01

    The objective of this study was to evaluate the test-retest reliability of the trunk muscle activity distribution in asymptomatic participants during muscle fatigue using large-array surface electromyography (EMG). Trunk muscle activity distribution was evaluated twice, with 3 to 4 days between them, in 27 asymptomatic volunteers using large-array surface EMG. Motor variability, assessed with 2 different variables (the centroid coordinates of the root mean square map and the dispersion variable), was evaluated during a low back muscle fatigue task. Test-retest reliability of muscle activity distribution was obtained using Pearson correlation coefficients. A shift in the distribution of EMG amplitude toward the lateral-caudal region of the lumbar erector spinae induced by muscle fatigue was observed. Moderate to very strong correlations were found between both sessions in the last 3 phases of the fatigue task for both motor variability variables, whereas weak to moderate correlations were found in the first phases of the fatigue task only for the dispersion variable. These findings show that, in asymptomatic participants, patterns of EMG activity are less reliable in initial stages of muscle fatigue, whereas later stages are characterized by highly reliable patterns of EMG activity. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  2. North Atlantic atmospheric circulation and surface wind in the Northeast of the Iberian Peninsula: uncertainty and long term downscaled variability

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Bustamante, E.; Jimenez, P.A. [CIEMAT, Departamento de Energias Renovables, Madrid (Spain); Universidad Complutense de Madrid, Departamento de Astrofisica y CC. de la Atmosfera, Madrid (Spain); Gonzalez-Rouco, J.F. [Universidad Complutense de Madrid, Departamento de Astrofisica y CC. de la Atmosfera, Madrid (Spain); Navarro, J. [CIEMAT, Departamento de Energias Renovables, Madrid (Spain); Xoplaki, E. [University of Bern, Institute of Geography and Oeschger Centre for Climate Change Research, Bern (Switzerland); Montavez, J.P. [Universidad de Murcia, Departamento de Fisica, Murcia (Spain)

    2012-01-15

    The variability and predictability of the surface wind field at the regional scale is explored over a complex terrain region in the northeastern Iberian Peninsula by means of a downscaling technique based on Canonical Correlation Analysis. More than a decade of observations (1992-2005) allows for calibrating and validating a statistical method that elicits the main associations between the large scale atmospheric circulation over the North Atlantic and Mediterranean areas and the regional wind field. In an initial step the downscaling model is designed by selecting parameter values from practise. To a large extent, the variability of the wind at monthly timescales is found to be governed by the large scale circulation modulated by the particular orographic features of the area. The sensitivity of the downscaling methodology to the selection of the model parameter values is explored, in a second step, by performing a systematic sampling of the parameters space, avoiding a heuristic selection. This provides a metric for the uncertainty associated with the various possible model configurations. The uncertainties associated with the model configuration are considerably dependent on the spatial variability of the wind. While the sampling of the parameters space in the model set up moderately impact estimations during the calibration period, the regional wind variability is very sensitive to the parameters selection at longer timescales. This fact illustrates that downscaling exercises based on a single configuration of parameters should be interpreted with extreme caution. The downscaling model is used to extend the estimations several centuries to the past using long datasets of sea level pressure, thereby illustrating the large temporal variability of the regional wind field from interannual to multicentennial timescales. The analysis does not evidence long term trends throughout the twentieth century, however anomalous episodes of high/low wind speeds are identified

  3. The intraseasonal variability of winter semester surface air temperature in Antarctica

    Directory of Open Access Journals (Sweden)

    Lejiang Yu

    2011-02-01

    Full Text Available This study investigates systematically the intraseasonal variability of surface air temperature over Antarctica by applying empirical orthogonal function (EOF analysis to the National Centers for Environmental Prediction, US Department of Energy, Reanalysis 2 data set for the period of 1979 through 2007. The results reveal the existence of two major intraseasonal oscillations of surface temperature with periods of 26–30 days and 14 days during the Antarctic winter season in the region south of 60°S. The first EOF mode shows a nearly uniform spatial pattern in Antarctica and the Southern Ocean associated with the Antarctic Oscillation. The mode-1 intraseasonal variability of the surface temperature leads that of upper atmosphere by one day with the largest correlation at 300-hPa level geopotential heights. The intraseasonal variability of the mode-1 EOF is closely related to the variations of surface net longwave radiation the total cloud cover over Antarctica. The other major EOF modes reveal the existence of eastward propagating phases over the Southern Ocean and marginal region in Antarctica. The leading two propagating modes respond to Pacific–South American modes. Meridional winds induced by the wave train from the tropics have a direct influence on the surface air temperature over the Southern Ocean and the marginal region of the Antarctic continent.

  4. Detection and variability of the Congo River plume from satellite derived sea surface temperature, salinity, ocean colour and sea level

    Science.gov (United States)

    Hopkins, Jo; Lucas, Marc; Dufau, Claire; Sutton, Marion; Lauret, Olivier

    2013-04-01

    The Congo River in Africa has the world's second highest annual mean daily freshwater discharge and is the second largest exporter of terrestrial organic carbon into the oceans. It annually discharges an average of 1,250 × 109 m3 of freshwater into the southeast Atlantic producing a vast fresh water plume, whose signature can be traced hundreds of kilometres from the river mouth. Large river plumes such as this play important roles in the ocean carbon cycle, often functioning as carbon sinks. An understanding of their extent and seasonality is therefore essential if they are to be realistically accounted for in global assessments of the carbon cycle. Despite its size, the variability and dynamics of the Congo plume are minimally documented. In this paper we analyse satellite derived sea surface temperature, salinity, ocean colour and sea level anomaly to describe and quantify the extent, strength and variability of the far-field plume and to explain its behaviour in relation to winds, ocean currents and fresh water discharge. Empirical Orthogonal Function analysis reveals strong seasonal and coastal upwelling signals, potential bimodal seasonality of the Angola Current and responses to fresh water discharge peaks in all data sets. The strongest plume-like signatures however were found in the salinity and ocean colour where the dominant sources of variability come from the Congo River itself, rather than from the wider atmosphere and ocean. These two data sets are then analysed using a statistically based water mass detection technique to isolate the behaviour of the plume. The Congo's close proximity to the equator means that the influence of the earth's rotation on the fresh water inflow is relatively small and the plume tends not to form a distinct coastal current. Instead, its behaviour is determined by wind and surface circulation patterns. The main axis of the plume between November and February, following peak river discharge, is oriented northwest, driven

  5. Observed metre scale horizontal variability of elemental carbon in surface snow

    International Nuclear Information System (INIS)

    Svensson, J; Lihavainen, H; Ström, J; Hansson, M; Kerminen, V-M

    2013-01-01

    Surface snow investigated for its elemental carbon (EC) concentration, based on a thermal–optical method, at two different sites during winter and spring of 2010 demonstrates metre scale horizontal variability in concentration. Based on the two sites sampled, a clean and a polluted site, the clean site (Arctic Finland) presents the greatest variability. In side-by-side ratios between neighbouring samples, 5 m apart, a ratio of around two was observed for the clean site. The median for the polluted site had a ratio of 1.2 between neighbouring samples. The results suggest that regions exposed to snowdrift may be more sensitive to horizontal variability in EC concentration. Furthermore, these results highlight the importance of carefully choosing sampling sites and timing, as each parameter will have some effect on EC variability. They also emphasize the importance of gathering multiple samples from a site to obtain a representative value for the area. (letter)

  6. In silico, experimental, mechanistic model for extended-release felodipine disposition exhibiting complex absorption and a highly variable food interaction.

    Directory of Open Access Journals (Sweden)

    Sean H J Kim

    Full Text Available The objective of this study was to develop and explore new, in silico experimental methods for deciphering complex, highly variable absorption and food interaction pharmacokinetics observed for a modified-release drug product. Toward that aim, we constructed an executable software analog of study participants to whom product was administered orally. The analog is an object- and agent-oriented, discrete event system, which consists of grid spaces and event mechanisms that map abstractly to different physiological features and processes. Analog mechanisms were made sufficiently complicated to achieve prespecified similarity criteria. An equation-based gastrointestinal transit model with nonlinear mixed effects analysis provided a standard for comparison. Subject-specific parameterizations enabled each executed analog's plasma profile to mimic features of the corresponding six individual pairs of subject plasma profiles. All achieved prespecified, quantitative similarity criteria, and outperformed the gastrointestinal transit model estimations. We observed important subject-specific interactions within the simulation and mechanistic differences between the two models. We hypothesize that mechanisms, events, and their causes occurring during simulations had counterparts within the food interaction study: they are working, evolvable, concrete theories of dynamic interactions occurring within individual subjects. The approach presented provides new, experimental strategies for unraveling the mechanistic basis of complex pharmacological interactions and observed variability.

  7. Improving evapotranspiration in a land surface model using biophysical variables derived from MSG/SEVIRI satellite

    Directory of Open Access Journals (Sweden)

    N. Ghilain

    2012-08-01

    Full Text Available Monitoring evapotranspiration over land is highly dependent on the surface state and vegetation dynamics. Data from spaceborn platforms are desirable to complement estimations from land surface models. The success of daily evapotranspiration monitoring at continental scale relies on the availability, quality and continuity of such data. The biophysical variables derived from SEVIRI on board the geostationary satellite Meteosat Second Generation (MSG and distributed by the Satellite Application Facility on Land surface Analysis (LSA-SAF are particularly interesting for such applications, as they aimed at providing continuous and consistent daily time series in near-real time over Africa, Europe and South America. In this paper, we compare them to monthly vegetation parameters from a database commonly used in numerical weather predictions (ECOCLIMAP-I, showing the benefits of the new daily products in detecting the spatial and temporal (seasonal and inter-annual variability of the vegetation, especially relevant over Africa. We propose a method to handle Leaf Area Index (LAI and Fractional Vegetation Cover (FVC products for evapotranspiration monitoring with a land surface model at 3–5 km spatial resolution. The method is conceived to be applicable for near-real time processes at continental scale and relies on the use of a land cover map. We assess the impact of using LSA-SAF biophysical variables compared to ECOCLIMAP-I on evapotranspiration estimated by the land surface model H-TESSEL. Comparison with in-situ observations in Europe and Africa shows an improved estimation of the evapotranspiration, especially in semi-arid climates. Finally, the impact on the land surface modelled evapotranspiration is compared over a north–south transect with a large gradient of vegetation and climate in Western Africa using LSA-SAF radiation forcing derived from remote sensing. Differences are highlighted. An evaluation against remote sensing derived land

  8. Interannual Variation of Surface Circulation in the Japan/East Sea due to External Forcings and Intrinsic Variability

    Science.gov (United States)

    Choi, Byoung-Ju; Cho, Seong Hun; Jung, Hee Seok; Lee, Sang-Ho; Byun, Do-Seong; Kwon, Kyungman

    2018-03-01

    The interannual variation of surface ocean currents can be as large as seasonal variation in the Japan/East Sea (JES). To identify the major factors that cause such interannual variability of surface ocean circulation in the JES, surface circulation was simulated from 1998 to 2009 using a three-dimensional model. Contributions of atmospheric forcing (ATM), open boundary data (OBC), and intrinsic variability (ITV) of the surface flow in the JES on the interannual variability of surface ocean circulation were separately examined using numerical simulations. Variability in surface circulation was quantified in terms of variance in sea surface height, 100-m depth water temperature, and surface currents. ITV was found to be the dominant factor that induced interannual variabilities of surface circulation, the main path of the East Korea Warm Current (EKWC), and surface kinetic energy on a time scale of 2-4 years. OBC and ATM were secondary factors contributing to the interannual variation of surface circulation. Interannual variation of ATM changed the separation latitude of EKWC and increased the variability of surface circulation in the Ulleung Basin. Interannual variation of OBC enhanced low-frequency changes in surface circulation and eddies in the Yamato Basin. It also modulated basin-wide uniform oscillations of sea level. This study suggests that precise estimation of initial conditions using data assimilation is essential for long-term prediction of surface circulation in the JES.

  9. Extended spawning in brown trout (Salmo trutta populations from the Southern Iberian Peninsula: the role of climate variability

    Directory of Open Access Journals (Sweden)

    José E. Larios-López

    2014-02-01

    Full Text Available The reproductive periods of brown trout (Salmo trutta populations in 12 rivers in the Baetic Mountains in southern Spain were studied from 2008 to 2013. This area is an ecological and geographical limit for the distribution of this species in Europe. We found that the spawning period has been markedly extended in these fish. The mean spawning dates in the studied populations are consistent with the European trend at this latitude, but our data suggest that females from most of the populations that we studied are able to produce eggs from early October through late April or early May, yielding a reproductive period of between 150 and 170 days, the longest and most delayed brown trout reproduction periods that have been reported in the literature. We believe that such expanded spawning periods result primarily from the unpredictability of the Mediterranean climate, although it is possible that other factors may have contributed to the development of this reproductive behaviour. This hypothesis is discussed in the context of a comparison of our results with those found for other European S. trutta populations.

  10. Quantitative analysis by X-ray fractography of fatigue fractured surface under variable amplitude loading

    International Nuclear Information System (INIS)

    Akita, Koichi; Kodama, Shotaro; Misawa, Hiroshi

    1994-01-01

    X-ray fractography is a method of analysing the causes of accidental fracture of machine components or structures. Almost all of the previous research on this problem has been carried out using constant amplitude fatigue tests. However, the actual loads on components and structures are usually of variable amplitudes. In this study, X-ray fractography was applied to fatigue fractured surfaces produced by variable amplitude loading. Fatigue tests were carried out on Ni-Cr-Mo steel CT specimens under the conditions of repeated, two-step and multiple-step loading. Residual stresses were measured on the fatigue fractured surface by an X-ray diffraction method. The relationships between residual stress and stress intensity factor or crack propagation rate were studied. They were discussed in terms of the quantitative expressions under constant amplitude loading, proposed by the authors in previous papers. The main results obtained were as follows : (1) It was possible to estimate the crack propagation rate of the fatigue fractured surface under variable amplitude loading by using the relationship between residual stress and stress intensity factor under constant amplitude loading. (2) The compressive residual stress components on the fatigue fractured surface correspond with cyclic softening of the material rather than with compressive plastic deformation at the crack tip. (author)

  11. Stagnation-point flow of second grade nanofluid towards a nonlinear stretching surface with variable thickness

    Directory of Open Access Journals (Sweden)

    Rai Sajjad Saif

    Full Text Available This paper investigates the stagnation point flow of second grade nanomaterial towards a nonlinear stretching surface subject to variable surface thickness. The process of heat transfer is examined through the melting heat and mixed convection effects. Further novel features regarding Brownian motion and thermophoresis are present. Boundary-layer approximation is employed in the problem formulation. Momentum, energy and concentration equations are converted into the non-linear ordinary differential system through the appropriate transformations. Convergent solutions for resulting problem are computed. Behaviors of various sundry variables on temperature and concentration are studied in detail. The skin friction coefficient and heat and mass transfer rates are also computed and analyzed. Our results indicate that the temperature and concentration distributions are enhanced for larger values of thermophoresis parameter. Further the present work is hoped to be useful in improving the performance of heat transfer of base fluid. Keywords: Stagnation-point flow, Second grade fluid, Nanoparticles, Melting heat process, Nonlinear stretching surface, Variable surface thickness

  12. Variability of nutrient and thermal structure in surface waters between New Zealand and Antarctica, October 2004–January 2005

    Directory of Open Access Journals (Sweden)

    Alessandra Campanelli

    2011-04-01

    Full Text Available We describe the upper ocean thermal structure and surface nutrient concentrations between New Zealand and Antarctica along five transects that cross the Subantarctic Front, the Polar Front (PF and the southern Antarctic Circumpolar Current (ACC front. The surface water thermal structure is coupled with variations in surface nutrient concentrations, making water masses identifiable by both temperature and nutrient ranges. In particular, a strong latitudinal gradient in orthosilicate concentration is centred at the PF. On the earlier sections that extend south-west from the Campbell Plateau, orthosilicate increases sharply southward from 10–15 to 50–55 µmol l−1 between 58° S and 60° S, while surface temperature drops from 7°C to 2°C. Nitrate increases more regularly toward the south, with concentrations ranging from 10–12 µmol l−1 at 54° S to 25–30 µmol l−1 at 66° S. The same features are observed during the later transects between New Zealand and the Ross Sea, but the sharp silica and surface temperature gradients are shifted between 60° S and 64° S. Both temporal and spatial factors may influence the observed variability. The January transect suggests an uptake of silica, orthophosphate and nitrate between 63° S and 70° S over the intervening month, with an average depletion near 37%, 44% and 29%, respectively. An N/P (nitrite + nitrate/orthophosphate apparent drawdown ratio of 8.8±4.1 and an Si/N (silicic acid/nitrite + nitrate apparent drawdown ratio >1 suggest this depletion results from a seasonal diatom bloom. A southward movement of the oceanic fronts between New Zealand and the Ross Sea relative to prior measurements is consistent with reports of recent warming and changes in the ACC.

  13. Annual and interannual variability of scatterometer ocean surface wind over the South China Sea

    DEFF Research Database (Denmark)

    Zhang, GS; Xu, Q.; Gong, Z.

    2014-01-01

    To investigate the annual and interannual variability of ocean surface wind over the South China Sea (SCS), the vector empirical orthogonal function (VEOF) method and the Hilbert-Huang transform (HHT) method were employed to analyze a set of combined satellite scatterometer wind data during.......3% of the total variance and represents the East Asian monsoon features. The second mode of VEOF corresponds to a spring-autumn oscillation which accounts for 8.3% of the total variance. To analyze the interannual variability, the annual signal was removed from the wind data set and the VEOFs of the residuals...

  14. MHD natural convection from a heated vertical wavy surface with variable viscosity and thermal conductivity

    International Nuclear Information System (INIS)

    Choudhury, M.; Hazarika, G.C.; Sibanda, P.

    2013-01-01

    We investigate the effects of temperature dependent viscosity and thermal conductivity on natural convection flow of a viscous incompressible electrically conducting fluid along a vertical wavy surface. The flow is permeated by uniform transverse magnetic field. The fluid viscosity and thermal conductivity are assumed to vary as inverse linear functions of temperature. The coupled non-linear systems of partial differential equations are solved using the finite difference method. The effects of variable viscosity parameter, variable thermal conductivity parameter and magnetic parameter on the flow field and the heat transfer characteristics are discussed and shown graphically. (author)

  15. Study of the Algorithm of Backtracking Decoupling and Adaptive Extended Kalman Filter Based on the Quaternion Expanded to the State Variable for Underwater Glider Navigation

    Directory of Open Access Journals (Sweden)

    Haoqian Huang

    2014-12-01

    Full Text Available High accuracy attitude and position determination is very important for underwater gliders. The cross-coupling among three attitude angles (heading angle, pitch angle and roll angle becomes more serious when pitch or roll motion occurs. This cross-coupling makes attitude angles inaccurate or even erroneous. Therefore, the high accuracy attitude and position determination becomes a difficult problem for a practical underwater glider. To solve this problem, this paper proposes backing decoupling and adaptive extended Kalman filter (EKF based on the quaternion expanded to the state variable (BD-AEKF. The backtracking decoupling can eliminate effectively the cross-coupling among the three attitudes when pitch or roll motion occurs. After decoupling, the adaptive extended Kalman filter (AEKF based on quaternion expanded to the state variable further smoothes the filtering output to improve the accuracy and stability of attitude and position determination. In order to evaluate the performance of the proposed BD-AEKF method, the pitch and roll motion are simulated and the proposed method performance is analyzed and compared with the traditional method. Simulation results demonstrate the proposed BD-AEKF performs better. Furthermore, for further verification, a new underwater navigation system is designed, and the three-axis non-magnetic turn table experiments and the vehicle experiments are done. The results show that the proposed BD-AEKF is effective in eliminating cross-coupling and reducing the errors compared with the conventional method.

  16. Study of the algorithm of backtracking decoupling and adaptive extended Kalman filter based on the quaternion expanded to the state variable for underwater glider navigation.

    Science.gov (United States)

    Huang, Haoqian; Chen, Xiyuan; Zhou, Zhikai; Xu, Yuan; Lv, Caiping

    2014-12-03

    High accuracy attitude and position determination is very important for underwater gliders. The cross-coupling among three attitude angles (heading angle, pitch angle and roll angle) becomes more serious when pitch or roll motion occurs. This cross-coupling makes attitude angles inaccurate or even erroneous. Therefore, the high accuracy attitude and position determination becomes a difficult problem for a practical underwater glider. To solve this problem, this paper proposes backing decoupling and adaptive extended Kalman filter (EKF) based on the quaternion expanded to the state variable (BD-AEKF). The backtracking decoupling can eliminate effectively the cross-coupling among the three attitudes when pitch or roll motion occurs. After decoupling, the adaptive extended Kalman filter (AEKF) based on quaternion expanded to the state variable further smoothes the filtering output to improve the accuracy and stability of attitude and position determination. In order to evaluate the performance of the proposed BD-AEKF method, the pitch and roll motion are simulated and the proposed method performance is analyzed and compared with the traditional method. Simulation results demonstrate the proposed BD-AEKF performs better. Furthermore, for further verification, a new underwater navigation system is designed, and the three-axis non-magnetic turn table experiments and the vehicle experiments are done. The results show that the proposed BD-AEKF is effective in eliminating cross-coupling and reducing the errors compared with the conventional method.

  17. Study of the Algorithm of Backtracking Decoupling and Adaptive Extended Kalman Filter Based on the Quaternion Expanded to the State Variable for Underwater Glider Navigation

    Science.gov (United States)

    Huang, Haoqian; Chen, Xiyuan; Zhou, Zhikai; Xu, Yuan; Lv, Caiping

    2014-01-01

    High accuracy attitude and position determination is very important for underwater gliders. The cross-coupling among three attitude angles (heading angle, pitch angle and roll angle) becomes more serious when pitch or roll motion occurs. This cross-coupling makes attitude angles inaccurate or even erroneous. Therefore, the high accuracy attitude and position determination becomes a difficult problem for a practical underwater glider. To solve this problem, this paper proposes backing decoupling and adaptive extended Kalman filter (EKF) based on the quaternion expanded to the state variable (BD-AEKF). The backtracking decoupling can eliminate effectively the cross-coupling among the three attitudes when pitch or roll motion occurs. After decoupling, the adaptive extended Kalman filter (AEKF) based on quaternion expanded to the state variable further smoothes the filtering output to improve the accuracy and stability of attitude and position determination. In order to evaluate the performance of the proposed BD-AEKF method, the pitch and roll motion are simulated and the proposed method performance is analyzed and compared with the traditional method. Simulation results demonstrate the proposed BD-AEKF performs better. Furthermore, for further verification, a new underwater navigation system is designed, and the three-axis non-magnetic turn table experiments and the vehicle experiments are done. The results show that the proposed BD-AEKF is effective in eliminating cross-coupling and reducing the errors compared with the conventional method. PMID:25479331

  18. External ocular surface and lens microbiota in contact lens wearers with corneal infiltrates during extended wear of hydrogel lenses.

    Science.gov (United States)

    Willcox, Mark; Sharma, Savitri; Naduvilath, Thomas J; Sankaridurg, Padmaja R; Gopinathan, Usha; Holden, Brien A

    2011-03-01

    To determine whether carriage of microbes on the contact lens or ocular surfaces during extended wear (EW) with soft hydroxyethyl methacrylate (HEMA)-based contact lenses predisposes the wearer to adverse events. Participants (non-contact lens wearers) were enrolled in a clinical study involving wear of HEMA-based hydrogel lenses on a six night EW basis with weekly replacement. Type and number of bacteria colonizing the lower lid margins, upper bulbar conjunctiva, and contact lenses during EW after one night, 1 week, 1 month, and thereafter every 3 months for 3.5 years were determined. The association of bacteria with adverse responses was compared between carriers (defined as having significant microbes cultured from two or more samples with 1 year) and noncarriers, and the strength of the association was estimated using multivariate logistic regression. Carriers of gram-positive bacteria on lenses (particularly coagulase negative staphylococci or Corynebacterium spp.) were approximately three and eight times more likely to develop contact lens-induced peripheral ulcers (CLPUs) and asymptomatic infiltrates (AIs), respectively. Staphylococcus aureus was most frequently isolated from lenses during CLPU. Carriers of gram-negative bacteria on lenses were five times more likely to develop contact lens-induced acute red eye (CLARE). Haemophilus influenzae was isolated most frequently from lenses during CLARE and AI events. Bacterial carriage on contact lenses during EW predisposes the wearer to the development of corneal inflammatory events including CLARE, CLPU, and AI.

  19. Characterization of the Deep Water Surface Wave Variability in the California Current Region

    Science.gov (United States)

    Villas Bôas, Ana B.; Gille, Sarah T.; Mazloff, Matthew R.; Cornuelle, Bruce D.

    2017-11-01

    Surface waves are crucial for the dynamics of the upper ocean not only because they mediate exchanges of momentum, heat, energy, and gases between the ocean and the atmosphere, but also because they determine the sea state. The surface wave field in a given region is set by the combination of local and remote forcing. The present work characterizes the seasonal variability of the deep water surface wave field in the California Current region, as retrieved from over two decades of satellite altimetry data combined with wave buoys and wave model hindcast (WaveWatch III). In particular, the extent to which the local wind modulates the variability of the significant wave height, peak period, and peak direction is assessed. During spring/summer, regional-scale wind events of up to 10 m/s are the dominant forcing for waves off the California coast, leading to relatively short-period waves (8-10 s) that come predominantly from the north-northwest. The wave climatology throughout the California Current region shows average significant wave heights exceeding 2 m during most of the year, which may have implications for the planning and retrieval methods of the Surface Water and Ocean Topography (SWOT) satellite mission.

  20. Elephant overflows: Multi-annual variability in Weddell Sea Deep Water driven by surface forcing

    Science.gov (United States)

    Meijers, Andrew; Meredith, Michael; Abrahamsen, Povl; Naviera-Garabato, Alberto; Ángel Morales Maqueda, Miguel; Polzin, Kurt

    2015-04-01

    The volume of the deepest and densest water mass in Drake Passage, Lower Weddell Sea Deep Water (LWSDW), is shown to have been decreasing over the last 20 years of observations, with an associated reduction in density driven by freshening. Superimposed on this long term trend is a multi-annual oscillation with a period of 3-5 years. This variability only appears in Drake Passage; observations in the east of the Scotia Sea show a similar long term trend, but with no apparent multi-annual variability. Clues as to the source of this variability may be found on the continental slope at approximately 1000 m immediately north of Elephant Island on the northern tip of the Antarctic Peninsula. Here there is an intermittent westward flowing cold/fresh slope current whose volume and properties are strongly correlated with the LWSDW multi-annual variability, although leading the LWSDW by around one year. As the slope current and LWSDW are separated from each other both geographically and in water mass characteristics, their co-variability implies that they are responding to a common forcing, while the lag between deep LWSDW and shallow slope current provides information on the timescale of this response. A newly available high resolution temperature and salinity multi-year time series from the Elephant Island slope at 1000 m is compared with reanalysis and model derived surface fluxes, sea ice extent and wind stress. We find that there are strong positive relationships between the surface wind stress and heat flux over the shelf at the tip of the Antarctic Peninsula and the properties of the slope current at 1000 m on seasonal to annual timescales. We use tracer release experiments in the Southern Ocean State Estimate (SOSE) model to investigate the lag between the slope current and LWSDW timeseries and hypothesise that the observed multi-annual variability in both water masses is driven by surface forcing over the shelf and the overflow of modified water from the slope in

  1. On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

    Science.gov (United States)

    Bengulescu, Marc; Blanc, Philippe; Wald, Lucien

    2018-01-01

    This study is concerned with the intrinsic temporal scales of the variability in the surface solar irradiance (SSI). The data consist of decennial time series of daily means of the SSI obtained from high-quality measurements of the broadband solar radiation impinging on a horizontal plane at ground level, issued from different Baseline Surface Radiation Network (BSRN) ground stations around the world. First, embedded oscillations sorted in terms of increasing timescales of the data are extracted by empirical mode decomposition (EMD). Next, Hilbert spectral analysis is applied to obtain an amplitude-modulation-frequency-modulation (AM-FM) representation of the data. The time-varying nature of the characteristic timescales of variability, along with the variations in the signal intensity, are thus revealed. A novel, adaptive null hypothesis based on the general statistical characteristics of noise is employed in order to discriminate between the different features of the data, those that have a deterministic origin and those being realizations of various stochastic processes. The data have a significant spectral peak corresponding to the yearly variability cycle and feature quasi-stochastic high-frequency variability components, irrespective of the geographical location or of the local climate. Moreover, the amplitude of this latter feature is shown to be modulated by variations in the yearly cycle, which is indicative of nonlinear multiplicative cross-scale couplings. The study has possible implications on the modeling and the forecast of the surface solar radiation, by clearly discriminating the deterministic from the quasi-stochastic character of the data, at different local timescales.

  2. Temporal and spatial variabilities in the surface moisture content of a fine-grained beach

    Science.gov (United States)

    Namikas, S. L.; Edwards, B. L.; Bitton, M. C. A.; Booth, J. L.; Zhu, Y.

    2010-01-01

    This study examined spatial and temporal variations in the surface moisture content of a fine-grained beach at Padre Island, Texas, USA. Surface moisture measurements were collected on a 27 × 24 m grid that extended from the dune toe to the upper foreshore. The grid was surveyed at 2 to 4 h intervals for two tidal cycles, generating 17 maps of the spatial distribution of surface moisture. Simultaneous measurements of air temperature and humidity, wind speed and direction, tidal elevation, and water table elevation were used to interpret observed changes in surface moisture. It was found that the spatial distribution of surface moisture was broadly characterized by a cross-shore gradient of high to low content moving landward from the swash zone. The distribution of surface moisture was conceptualized in terms of three zones: saturated (> 25%), intermediate or transitional (5-25%), and dry (< 5%). The position of the saturated zone corresponded to the uppermost swash zone and therefore shifted in accordance with tidal elevation. Moisture contents in the intermediate and dry zones were primarily related to variation in water table depth (which was in turn controlled by tidal elevation) and to a lesser extent by evaporation. Signals associated with atmospheric processes such as evaporation were muted by the minimal degree of variation in atmospheric parameters experienced during most of the study period, but were apparent for the last few hours. The observed spatial and temporal variations in moisture content correspond reasonably well with observations of key controlling processes, but more work is needed to fully characterize this process suite.

  3. Surface display of a massively variable lipoprotein by a Legionella diversity-generating retroelement.

    Science.gov (United States)

    Arambula, Diego; Wong, Wenge; Medhekar, Bob A; Guo, Huatao; Gingery, Mari; Czornyj, Elizabeth; Liu, Minghsun; Dey, Sanghamitra; Ghosh, Partho; Miller, Jeff F

    2013-05-14

    Diversity-generating retroelements (DGRs) are a unique family of retroelements that confer selective advantages to their hosts by facilitating localized DNA sequence evolution through a specialized error-prone reverse transcription process. We characterized a DGR in Legionella pneumophila, an opportunistic human pathogen that causes Legionnaires disease. The L. pneumophila DGR is found within a horizontally acquired genomic island, and it can theoretically generate 10(26) unique nucleotide sequences in its target gene, legionella determinent target A (ldtA), creating a repertoire of 10(19) distinct proteins. Expression of the L. pneumophila DGR resulted in transfer of DNA sequence information from a template repeat to a variable repeat (VR) accompanied by adenine-specific mutagenesis of progeny VRs at the 3'end of ldtA. ldtA encodes a twin-arginine translocated lipoprotein that is anchored in the outer leaflet of the outer membrane, with its C-terminal variable region surface exposed. Related DGRs were identified in L. pneumophila clinical isolates that encode unique target proteins with homologous VRs, demonstrating the adaptability of DGR components. This work characterizes a DGR that diversifies a bacterial protein and confirms the hypothesis that DGR-mediated mutagenic homing occurs through a conserved mechanism. Comparative bioinformatics predicts that surface display of massively variable proteins is a defining feature of a subset of bacterial DGRs.

  4. Self-assembling peptide detergents stabilize isolated photosystem I on a dry surface for an extended time.

    Directory of Open Access Journals (Sweden)

    Patrick Kiley

    2005-07-01

    Full Text Available We used a class of designed peptide detergents to stabilize photosystem I (PS-I upon extended drying under N2 on a gold-coated-Ni-NTA glass surface. PS-I is a chlorophyll-containing membrane protein complex that is the primary reducer of ferredoxin and the electron acceptor of plastocyanin. We isolated the complex from the thylakoids of spinach chloroplasts using a chemical detergent. The chlorophyll molecules associated with the PS-I complex provide an intrinsic steady-state emission spectrum between 650 and 800 nm at -196.15 degrees C that reflects the organization of the pigment-protein interactions. In the absence of detergents, a large blue shift of the fluorescence maxima from approximately 735 nm to approximately 685 nm indicates a disruption in light-harvesting subunit organization, thus revealing chlorophyll-protein interactions. The commonly used membrane protein-stabilizing detergents, N-dodecyl-beta-D-maltoside and N-octyl-beta-D-glucoside, only partially stabilized the approximately 735-nm complex with approximately 685-nm spectroscopic shift. However, prior to drying, addition of the peptide detergent acetyl-AAAAAAK at increasing concentration significantly stabilized the PS-I complex. Moreover, in the presence of acetyl-AAAAAAK, the PS-I complex is stable in a dried form at room temperature for at least 3 wk. Another peptide detergent, acetyl-VVVVVVD, also stabilized the complex but to a lesser extent. These observations suggest that the peptide detergents may effectively stabilize membrane proteins in the solid-state. These designed peptide detergents may facilitate the study of diverse types of membrane proteins.

  5. An Extended Surface Loop on Toxoplasma gondii Apical Membrane Antigen 1 (AMA1 Governs Ligand Binding Selectivity.

    Directory of Open Access Journals (Sweden)

    Michelle L Parker

    Full Text Available Apicomplexan parasites are the causative agents of globally prevalent diseases including malaria and toxoplasmosis. These obligate intracellular pathogens have evolved a sophisticated host cell invasion strategy that relies on a parasite-host cell junction anchored by interactions between apical membrane antigens (AMAs on the parasite surface and rhoptry neck 2 (RON2 proteins discharged from the parasite and embedded in the host cell membrane. Key to formation of the AMA1-RON2 complex is displacement of an extended surface loop on AMA1 called the DII loop. While conformational flexibility of the DII loop is required to expose the mature RON2 binding groove, a definitive role of this substructure has not been elucidated. To establish a role of the DII loop in Toxoplasma gondii AMA1, we engineered a form of the protein where the mobile portion of the loop was replaced with a short Gly-Ser linker (TgAMA1ΔDIIloop. Isothermal titration calorimetry measurements with a panel of RON2 peptides revealed an influential role for the DII loop in governing selectivity. Most notably, an Eimeria tenella RON2 (EtRON2 peptide that showed only weak binding to TgAMA1 bound with high affinity to TgAMA1ΔDIIloop. To define the molecular basis for the differential binding, we determined the crystal structure of TgAMA1ΔDIIloop in complex with the EtRON2 peptide. When analyzed in the context of existing AMA1-RON2 structures, spatially distinct anchor points in the AMA1 groove were identified that, when engaged, appear to provide the necessary traction to outcompete the DII loop. Collectively, these data support a model where the AMA1 DII loop serves as a structural gatekeeper to selectively filter out ligands otherwise capable of binding with high affinity in the AMA1 apical groove. These data also highlight the importance of considering the functional implications of the DII loop in the ongoing development of therapeutic intervention strategies targeting the AMA1-RON

  6. Design method of a power management strategy for variable battery capacities range-extended electric vehicles to improve energy efficiency and cost-effectiveness

    International Nuclear Information System (INIS)

    Du, Jiuyu; Chen, Jingfu; Song, Ziyou; Gao, Mingming; Ouyang, Minggao

    2017-01-01

    Energy management strategy and battery capacity are the primary factors for the energy efficiency of range-extended electric buses (REEBs). To improve the energy efficiency of REEBs developed by Tsinghua University, an optimal design method of global optimization-based strategy is investigated. It is real-time and adaptive to variable traction battery capacities of series REEBs. For simulation, the physical model of REEB and key components are established. The optimal strategy is first extracted by the power split ratio (PSR) from REEB simulation result with dynamic program (DP) algorithm. The power distribution map is obtained by series simulations for variable battery capacity options. The control law for developing optimal strategy are achieved by cluster regression for power distribution data. To verify the effect of the proposed energy management strategy, characteristics of powertrain, energy efficiency, operating cost, and computing time are ultimately analyzed. Simulation results show that the energy efficiency of the global optimization-based strategy presented in this paper is similar to that of the DP strategy. Therefore, the overall energy efficiency can be significantly improved compared with that of the CDCS strategy, and operating costs can be substantially reduced. The feasibility of candidate control strategies is thereby assessed via the employment of variable parameters. - Highlights: • Analysis method of powertrain energy efficiency and power distribution is proposed. • The power distribution rules of strategy with variable battery capacities are achieved. • The parametric method of proposed PSR-RB strategy is presented. • The energy efficiency of powertrain is analysis by flow analysis method. • The energy management strategy is global optimization-based and real-time.

  7. The Flow of a Variable Viscosity Fluid down an Inclined Plane with a Free Surface

    Directory of Open Access Journals (Sweden)

    M. S. Tshehla

    2013-01-01

    Full Text Available The effect of a temperature dependent variable viscosity fluid flow down an inclined plane with a free surface is investigated. The fluid film is thin, so that lubrication approximation may be applied. Convective heating effects are included, and the fluid viscosity decreases exponentially with temperature. In general, the flow equations resulting from the variable viscosity model must be solved numerically. However, when the viscosity variation is small, then an asymptotic approximation is possible. The full solutions for the temperature and velocity profiles are derived using the Runge-Kutta numerical method. The flow controlling parameters such as the nondimensional viscosity variation parameter, the Biot and the Brinkman numbers, are found to have a profound effect on the resulting flow profiles.

  8. Fluctuations in heart rate variability of health care workers during four consecutive extended work shifts and recovery during rest and sleep.

    Science.gov (United States)

    Goffeng, Elisabeth M; Nordby, Karl-Christian; Tarvainen, Mika P; Järvelin-Pasanen, Susanna; Wagstaff, Anthony; Goffeng, Lars Ole; Bugge, Merete; Skare, Øivind; Sigstad Lie, Jenny-Anne

    2018-04-07

    The aim of this study was to investigate fluctuations in heart rate variability (HRV), which reflect autonomic nervous system (ANS) function and potential psychological and physical strain, among 24 health care workers during work and sleep during four consecutive extended work shifts. Data included 24/36/12 h of HRV measurements, two logbooks, and a questionnaire. A cross-shift/cross-week design was applied. HRV was measured during work, leisure time, and sleep. The HRV data included time-domain [mean RR, SD of normal to normal R-R intervals (SDNN), and root mean square of the successive differences (RMSSD)] and frequency-domain [low frequency (LF)/high frequency (HF) ratio] parameters. HRV parameters revealed significant differences among work, leisure time, and sleep. Mean RR, RMSSD, and SDNN values were lower and the LF/HF ratio was higher on the first versus last day of the work period; however, the differences were most prominent in the morning hours. The results indicate higher levels of cardiovascular stress on the first versus fourth day of the working period, and measurements at night indicate a satisfactory recovery from the extended shifts.

  9. Climatic variability of river outflow in the Pantanal region and the influence of sea surface temperature

    Science.gov (United States)

    Silva, Carlos Batista; Silva, Maria Elisa Siqueira; Ambrizzi, Tércio

    2017-07-01

    This paper investigates possible linear relationships between climate, hydrology, and oceanic surface variability in the Pantanal region (in South America's central area), over interannual and interdecadal time ranges. In order to verify the mentioned relations, lagged correlation analysis and linear adjustment between river discharge at the Pantanal region and sea surface temperature were used. Composite analysis for atmospheric fields, air humidity flux divergence, and atmospheric circulation at low and high levels, for the period between 1970 and 2003, was analyzed. Results suggest that the river discharge in the Pantanal region is linearly associated with interdecadal and interannual oscillations in the Pacific and Atlantic oceans, making them good predictors to continental hydrological variables. Considering oceanic areas, 51 % of the annual discharge in the Pantanal region can be linearly explained by mean sea surface temperature (SST) in the Subtropical North Pacific, Tropical North Pacific, Extratropical South Pacific, and Extratropical North Atlantic over the period. Considering a forecast approach in seasonal scale, 66 % of the monthly discharge variance in Pantanal, 3 months ahead of SST, is explained by the oceanic variables, providing accuracy around 65 %. Annual discharge values in the Pantanal region are strongly related to the Pacific Decadal Oscillation (PDO) variability (with 52 % of linear correlation), making it possible to consider an interdecadal variability and a consequent subdivision of the whole period in three parts: 1st (1970-1977), 2nd (1978-1996), and 3rd (1997-2003) subperiods. The three subperiods coincide with distinct PDO phases: negative, positive, and negative, respectively. Convergence of humidity flux at low levels and the circulation pattern at high levels help to explain the drier and wetter subperiods. During the wetter 2nd subperiod, the air humidity convergence at low levels is much more evident than during the other two

  10. Hourly to Decadal variability of sea surface carbon parameters in the north western Mediteranean Sea

    Science.gov (United States)

    Boutin, Jacqueline; Merlivat, Liliane; Antoine, David; Beaumont, Laurence; Golbol, Melek; Velluci, Vincenzo

    2017-04-01

    Sea surface CO2 fugacity, fCO2, is recorded hourly in the north western Mediterranean Sea since 2013 by two CARIOCA (Carbon Interface Ocean Atmosphere) sensors installed on the BOUSSOLE (Buoy for the acquisition of long term optical time series, http://www.obs-vlfr.fr/Boussole/html/project/introduction.php) mooring at 3m and 10m depth. fCO2 exhibits a large seasonal cycle, about 150 microatm peak to peak, very consistent with earlier CARIOCA measurements taken in 1995-1999 at the DYFAMED site (located 6km apart from the BOUSSOLE mooring) (Hood and Merlivat, JMR, 2001; Copin-Montegut et al., Mar. Chem., 2004): this seasonal cycle is driven primarily by intense mixing in Winter, biological uptake during Spring and warming during Summer. Interannual variability of these processes leads to interannual variability of monthly mean fCO2 that can reach more than 20 microatm. The short term variability (1 hour to 1 week) is large, especially during Summer 2014 (more than 40 microatm) due to a very strong vertical stratification and to the influence of internal waves. The hourly CARIOCA measurements allow to correctly filter out the high frequency variability while the three year long time series allow to smooth out interannual variability. Hence, for the first time, we get a precise estimate of the change of fCO2 in surface waters within 20 years. Over the 1995-2015 interval, we estimate an increase of fCO2 computed at a constant temperature of 13˚ C equal to 1.8 microatm per year. Given the alkalinity/salinity relationship in this region, we estimate mean annual rates of change of -0.0023+/-0.0001 pH unit and of +1.47+/-0.03 μmol kg-1 for pH and DIC respectively. These results give a quantitative estimate of the penetration of anthropogenic carbon in the surface waters of the northwestern Mediterranean Sea, about 80% via air-sea exchange and 20% via transport of carbon from the Atlantic across the Strait of Gibraltar as suggested by Palmieri et al (BG, 2015). We estimate

  11. A variable temperature cryostat that produces in situ clean-up germanium detector surfaces

    International Nuclear Information System (INIS)

    Pehl, R.H.; Madden, N.W.; Malone, D.F.; Cork, C.P.; Landis, D.A.; Xing, J.S.; Friesel, D.L.

    1988-11-01

    Variable temperature cryostats that can maintain germanium detectors at temperatures from 82 K to about 400 K while the thermal shield surrounding the detectors remains much colder when the detectors are warmed have been developed. Cryostats such as these offer the possibility of cryopumping material from the surface of detectors to the colder thermal shield. The diode characteristics of several detectors have shown very significant improvement following thermal cycles up to about 150 K in these cryostats. Important applications for cryostats having this attribute are many. 4 figs

  12. A variable pressure method for characterizing nanoparticle surface charge using pore sensors.

    Science.gov (United States)

    Vogel, Robert; Anderson, Will; Eldridge, James; Glossop, Ben; Willmott, Geoff

    2012-04-03

    A novel method using resistive pulse sensors for electrokinetic surface charge measurements of nanoparticles is presented. This method involves recording the particle blockade rate while the pressure applied across a pore sensor is varied. This applied pressure acts in a direction which opposes transport due to the combination of electro-osmosis, electrophoresis, and inherent pressure. The blockade rate reaches a minimum when the velocity of nanoparticles in the vicinity of the pore approaches zero, and the forces on typical nanoparticles are in equilibrium. The pressure applied at this minimum rate can be used to calculate the zeta potential of the nanoparticles. The efficacy of this variable pressure method was demonstrated for a range of carboxylated 200 nm polystyrene nanoparticles with different surface charge densities. Results were of the same order as phase analysis light scattering (PALS) measurements. Unlike PALS results, the sequence of increasing zeta potential for different particle types agreed with conductometric titration.

  13. Seasonal and spatial variability of surface ozone over China: contributions from background and domestic pollution

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2011-04-01

    Full Text Available Both observations and a 3-D chemical transport model suggest that surface ozone over populated eastern China features a summertime trough and that the month when surface ozone peaks differs by latitude and region. Source-receptor analysis is used to quantify the contributions of background ozone and Chinese anthropogenic emissions on this variability. Annual mean background ozone over China shows a spatial gradient from 55 ppbv in the northwest to 20 ppbv in the southeast, corresponding with changes in topography and ozone lifetime. Pollution background ozone (annual mean of 12.6 ppbv shows a minimum in the summer and maximum in the spring. On the monthly-mean basis, Chinese pollution ozone (CPO has a peak of 20–25 ppbv in June north of the Yangtze River and in October south of it, which explains the peaks of surface ozone in these months. The summertime trough in surface ozone over eastern China can be explained by the decrease of background ozone from spring to summer (by −15 ppbv regionally averaged over eastern China. Tagged simulations suggest that long-range transport of ozone from northern mid-latitude continents (including Europe and North America reaches a minimum in the summer, whereas ozone from Southeast Asia exhibits a maximum in the summer over eastern China. This contrast in seasonality provides clear evidence that the seasonal switch in monsoonal wind patterns plays a significant role in determining the seasonality of background ozone over China.

  14. Differential Rotation in Sun-like Stars from Surface Variability and Asteroseismology

    Science.gov (United States)

    Nielsen, Martin Bo

    2017-03-01

    The Sun and other stars are known to oscillate. Through the study of small perturbations to the frequencies of these oscillations the rotation of the deep interior can be inferred. However, thus far the internal rotation of other Sun-like stars is unknown. The NASA Kepler mission has observed a multitude of Sun-like stars over a period of four years. This has provided high-quality photometric data that can be used to study the rotation of stars with two different techniques: asteroseismology and surface activity. Asteroseismology provides a means of measuring rotation in the stellar interior, while photometric variability from magnetically active regions are sensitive to rotation at the stellar surface. The combination of these two methods can be used to constrain the radial differential rotation in Sun-like stars. First, we developed an automated method for measuring the rotation of stars using surface variability. This method was initially applied to the entire Kepler catalog, out of which we detected signatures of rotation in 12,000 stars across the main sequence, providing robust estimates of the surface rotation rates and the associated errors. Second, we performed an asteroseismic analysis of six Sun-like stars, where we were able to measure the rotational splitting as a function of frequency in the p-mode envelope. This was done by dividing the oscillation spectrum into individual segments, and fitting a model independently to each segment. We found that the measured splittings were all consistent with a constant value, indicating little differential rotation. Third, we compared the asteroseismic rotation rates of five Sun-like stars to their surface rotation rates. We found that the values were in good agreement, again indicating little differential rotation between the regions where the two methods are most sensitive. Finally, we discuss how the surface rotation rates may be used as a prior on the seismic envelope rotation rate in a double-zone model

  15. Long-Term Variability of Satellite Lake Surface Water Temperatures in the Great Lakes

    Science.gov (United States)

    Gierach, M. M.; Matsumoto, K.; Holt, B.; McKinney, P. J.; Tokos, K.

    2014-12-01

    The Great Lakes are the largest group of freshwater lakes on Earth that approximately 37 million people depend upon for fresh drinking water, food, flood and drought mitigation, and natural resources that support industry, jobs, shipping and tourism. Recent reports have stated (e.g., the National Climate Assessment) that climate change can impact and exacerbate a range of risks to the Great Lakes, including changes in the range and distribution of certain fish species, increased invasive species and harmful algal blooms, declining beach health, and lengthened commercial navigation season. In this study, we will examine the impact of climate change on the Laurentian Great Lakes through investigation of long-term lake surface water temperatures (LSWT). We will use the ATSR Reprocessing for Climate: Lake Surface Water Temperature & Ice Cover (ARC-Lake) product over the period 1995-2012 to investigate individual and interlake variability. Specifically, we will quantify the seasonal amplitude of LSWTs, the first and last appearances of the 4°C isotherm (i.e., an important identifier of the seasonal evolution of the lakes denoting winter and summer stratification), and interpret these quantities in the context of global interannual climate variability such as ENSO.

  16. Joint spatiotemporal variability of global sea surface temperatures and global Palmer drought severity index values

    Science.gov (United States)

    Apipattanavis, S.; McCabe, G.J.; Rajagopalan, B.; Gangopadhyay, S.

    2009-01-01

    Dominant modes of individual and joint variability in global sea surface temperatures (SST) and global Palmer drought severity index (PDSI) values for the twentieth century are identified through a multivariate frequency domain singular value decomposition. This analysis indicates that a secular trend and variability related to the El Niño–Southern Oscillation (ENSO) are the dominant modes of variance shared among the global datasets. For the SST data the secular trend corresponds to a positive trend in Indian Ocean and South Atlantic SSTs, and a negative trend in North Pacific and North Atlantic SSTs. The ENSO reconstruction shows a strong signal in the tropical Pacific, North Pacific, and Indian Ocean regions. For the PDSI data, the secular trend reconstruction shows high amplitudes over central Africa including the Sahel, whereas the regions with strong ENSO amplitudes in PDSI are the southwestern and northwestern United States, South Africa, northeastern Brazil, central Africa, the Indian subcontinent, and Australia. An additional significant frequency, multidecadal variability, is identified for the Northern Hemisphere. This multidecadal frequency appears to be related to the Atlantic multidecadal oscillation (AMO). The multidecadal frequency is statistically significant in the Northern Hemisphere SST data, but is statistically nonsignificant in the PDSI data.

  17. Coralline algal barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability.

    Science.gov (United States)

    Hetzinger, S; Halfar, J; Zack, T; Mecking, J V; Kunz, B E; Jacob, D E; Adey, W H

    2013-01-01

    During the past decades climate and freshwater dynamics in the northwestern North Atlantic have undergone major changes. Large-scale freshening episodes, related to polar freshwater pulses, have had a strong influence on ocean variability in this climatically important region. However, little is known about variability before 1950, mainly due to the lack of long-term high-resolution marine proxy archives. Here we present the first multidecadal-length records of annually resolved Ba/Ca variations from Northwest Atlantic coralline algae. We observe positive relationships between algal Ba/Ca ratios from two Newfoundland sites and salinity observations back to 1950. Both records capture episodical multi-year freshening events during the 20th century. Variability in algal Ba/Ca is sensitive to freshwater-induced changes in upper ocean stratification, which affect the transport of cold, Ba-enriched deep waters onto the shelf (highly stratified equals less Ba/Ca). Algal Ba/Ca ratios therefore may serve as a new resource for reconstructing past surface ocean freshwater changes.

  18. Subseasonal Reversal of East Asian Surface Temperature Variability in Winter 2014/15

    Science.gov (United States)

    Xu, Xinping; Li, Fei; He, Shengping; Wang, Huijun

    2018-06-01

    Although there has been a considerable amount of research conducted on the East Asian winter-mean climate, subseasonal surface air temperature (SAT) variability reversals in the early and late winter remain poorly understood. In this study, we focused on the recent winter of 2014/15, in which warmer anomalies dominated in January and February but colder conditions prevailed in December. Moreover, Arctic sea-ice cover (ASIC) in September-October 2014 was lower than normal, and warmer sea surface temperature (SST) anomalies occurred in the Niño4 region in winter, together with a positive Pacific Decadal Oscillation (PDO|+) phase. Using observational data and CMIP5 historical simulations, we investigated the PDO|+ phase modulation upon the winter warm Niño4 phase (autumn ASIC reduction) influence on the subseasonal SAT variability of East Asian winter. The results show that, under a PDO|+ phase modulation, warm Niño4 SST anomalies are associated with a subseasonal delay of tropical surface heating and subsequent Hadley cell and Ferrel cell intensification in January-February, linking the tropical and midlatitude regions. Consistently, the East Asian jet stream (EAJS) is significantly decelerated in January-February and hence promotes the warm anomalies over East Asia. Under the PDO|+ phase, the decrease in ASIC is related to cold SST anomalies in the western North Pacific, which increase the meridional temperature gradient and generate an accelerated and westward-shifted EAJS in December. The westward extension of the EAJS is responsible for the eastward-propagating Rossby waves triggered by declining ASIC and thereby favors the connection between ASIC and cold conditions over East Asia.

  19. Coastal polynyas in the southern Weddell Sea: Variability of the surface energy budget

    Science.gov (United States)

    Renfrew, Ian A.; King, John C.; Markus, Thorsten

    2002-06-01

    The surface energy budget of coastal polynyas in the southern Weddell Sea has been evaluated for the period 1992-1998 using a combination of satellite observations, meteorological data, and simple physical models. The study focuses on polynyas that habitually form off the Ronne Ice Shelf. The coastal polynya areal data are derived from an advanced multichannel polynya detection algorithm applied to passive microwave brightness temperatures. The surface sensible and latent heat fluxes are calculated via a fetch-dependent model of the convective-thermal internal boundary layer. The radiative fluxes are calculated using well-established empirical formulae and an innovative cloud model. Standard meteorological variables that are required for the flux calculations are taken from automatic weather stations and from the National Centers for Environmental Production/National Center for Atmospheric Research reanalyses. The 7 year surface energy budget shows an overall oceanic warming due to the presence of coastal polynyas. For most of the period the summertime oceanic warming, due to the absorption of shortwave radiation, is approximately in balance with the wintertime oceanic cooling. However, the anomalously large summertime polynya of 1997-1998 allowed a large oceanic warming of the region. Wintertime freezing seasons are characterized by episodes of high heat fluxes interspersed with more quiescent periods and controlled by coastal polynya dynamics. The high heat fluxes are primarily due to the sensible heat flux component, with smaller complementary latent and radiative flux components. The average freezing season area-integrated energy exchange is 3.48 × 1019 J, with contributions of 63, 22, and 15% from the sensible, latent, and radiative components, respectively. The average melting season area-integrated energy exchange is -5.31 × 1019 J, almost entirely due to the radiative component. There is considerable interannual variability in the surface energy budget

  20. Geometric Parameters of Cutting Tools that Can be Used for Forming Sided Surfaces with Variable Profile

    Directory of Open Access Journals (Sweden)

    Razumov M.

    2017-03-01

    Full Text Available This article describes machining technology of polyhedral surfaces with varying profile, which is provided by planetary motion of multiblade block tools. The features of the technology and urgency of the problem is indicated. The purpose of the study is to determine the minimum value of the clearance angle of the tool. Also, the study is carried out about changing the value of the front and rear corners during the formation of polygonal surface using a planetary gear. The scheme of calculating the impact of various factors on the value of the minimum clearance angle of the tool and kinematic front and rear corners of the instrument is provided. The mathematical formula for calculating the minimum clearance angle of the tool is given. Also, given the formula for determining the front and rear corners of the tool during driving. This study can be used in the calculation of the design operations forming multifaceted external surfaces with a variable profile by using the planetary gear.

  1. Short-term variability of surface heat budget of the east central Arabian Sea during November, 1992

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, B.; Murty, V.S.N.; Rao, L.V.G.

    The analysis of surface meteorological data collected from the east central Arabian Sea during 10-28 November, 1992 revealed considerable variability in the meteorological parameters and heat budget components on both daily and diurnal time scales...

  2. Late holocene primary productivity and sea surface temperature variations in the northeastern Arabian Sea: Implications for winter monsoon variability.

    Digital Repository Service at National Institute of Oceanography (India)

    Boll, A.; Luckge, A.; Munz, P.; Forke, S.; Schulz, H.; Ramaswamy, V.; Rixen, T.; Gaye, B.; Emeis, K.-C.

    changes in winter monsoon strength with winds from the northeast that drive convective mixing and high surface ocean productivity in the northeastern Arabian Sea. To establish a high-resolution record of winter monsoon variability for the late Holocene, we...

  3. Estimation method of state-of-charge for lithium-ion battery used in hybrid electric vehicles based on variable structure extended kalman filter

    Science.gov (United States)

    Sun, Yong; Ma, Zilin; Tang, Gongyou; Chen, Zheng; Zhang, Nong

    2016-07-01

    Since the main power source of hybrid electric vehicle(HEV) is supplied by the power battery, the predicted performance of power battery, especially the state-of-charge(SOC) estimation has attracted great attention in the area of HEV. However, the value of SOC estimation could not be greatly precise so that the running performance of HEV is greatly affected. A variable structure extended kalman filter(VSEKF)-based estimation method, which could be used to analyze the SOC of lithium-ion battery in the fixed driving condition, is presented. First, the general lower-order battery equivalent circuit model(GLM), which includes column accumulation model, open circuit voltage model and the SOC output model, is established, and the off-line and online model parameters are calculated with hybrid pulse power characteristics(HPPC) test data. Next, a VSEKF estimation method of SOC, which integrates the ampere-hour(Ah) integration method and the extended Kalman filter(EKF) method, is executed with different adaptive weighting coefficients, which are determined according to the different values of open-circuit voltage obtained in the corresponding charging or discharging processes. According to the experimental analysis, the faster convergence speed and more accurate simulating results could be obtained using the VSEKF method in the running performance of HEV. The error rate of SOC estimation with the VSEKF method is focused in the range of 5% to 10% comparing with the range of 20% to 30% using the EKF method and the Ah integration method. In Summary, the accuracy of the SOC estimation in the lithium-ion battery cell and the pack of lithium-ion battery system, which is obtained utilizing the VSEKF method has been significantly improved comparing with the Ah integration method and the EKF method. The VSEKF method utilizing in the SOC estimation in the lithium-ion pack of HEV can be widely used in practical driving conditions.

  4. Mapping surface temperature variability on a debris-covered glacier with an unmanned aerial vehicle

    Science.gov (United States)

    Kraaijenbrink, P. D. A.; Litt, M.; Shea, J. M.; Treichler, D.; Koch, I.; Immerzeel, W.

    2016-12-01

    Debris-covered glacier tongues cover about 12% of the glacier surface in high mountain Asia and much of the melt water is generated from those glaciers. A thin layer of supraglacial debris enhances ice melt by lowering the albedo, while thicker debris insulates the ice and reduces melt. Data on debris thickness is therefore an important input for energy balance modelling of these glaciers. Thermal infrared remote sensing can be used to estimate the debris thickness by using an inverse relation between debris surface temperature and thickness. To date this has only been performed using coarse spaceborne thermal imagery, which cannot reveal small scale variation in debris thickness and its influence on the heterogeneous melt patterns on debris-covered glaciers. We deployed an unmanned aerial vehicle mounted with a thermal infrared sensor over the debris-covered Lirung Glacier in Nepal three times in May 2016 to reveal the spatial and temporal variability of surface temperature in high detail. The UAV survey matched a Landsat 8 overpass to be able to make a comparison with spaceborne thermal imagery. The UAV-acquired data is processed using Structure from Motion photogrammetry and georeferenced using DGPS-measured ground control points. Different surface types were distinguished by using data acquired by an additional optical UAV survey in order to correct for differences in surface emissivity. In situ temperature measurements and incoming solar radiation data are used to calibrate the temperature calculations. Debris thicknesses derived are validated by thickness measurements of a ground penetrating radar. Preliminary analysis reveals a spatially highly heterogeneous pattern of surface temperature over Lirung Glacier with a range in temperature of over 40 K. At dawn the debris is relatively cold and its temperature is influenced strongly by the ice underneath. Exposed to the high solar radiation at the high altitude the debris layer heats up very rapidly as sunrise

  5. Image-based Exploration of Iso-surfaces for Large Multi- Variable Datasets using Parameter Space.

    KAUST Repository

    Binyahib, Roba S.

    2013-05-13

    With an increase in processing power, more complex simulations have resulted in larger data size, with higher resolution and more variables. Many techniques have been developed to help the user to visualize and analyze data from such simulations. However, dealing with a large amount of multivariate data is challenging, time- consuming and often requires high-end clusters. Consequently, novel visualization techniques are needed to explore such data. Many users would like to visually explore their data and change certain visual aspects without the need to use special clusters or having to load a large amount of data. This is the idea behind explorable images (EI). Explorable images are a novel approach that provides limited interactive visualization without the need to re-render from the original data [40]. In this work, the concept of EI has been used to create a workflow that deals with explorable iso-surfaces for scalar fields in a multivariate, time-varying dataset. As a pre-processing step, a set of iso-values for each scalar field is inferred and extracted from a user-assisted sampling technique in time-parameter space. These iso-values are then used to generate iso- surfaces that are then pre-rendered (from a fixed viewpoint) along with additional buffers (i.e. normals, depth, values of other fields, etc.) to provide a compressed representation of iso-surfaces in the dataset. We present a tool that at run-time allows the user to interactively browse and calculate a combination of iso-surfaces superimposed on each other. The result is the same as calculating multiple iso- surfaces from the original data but without the memory and processing overhead. Our tool also allows the user to change the (scalar) values superimposed on each of the surfaces, modify their color map, and interactively re-light the surfaces. We demonstrate the effectiveness of our approach over a multi-terabyte combustion dataset. We also illustrate the efficiency and accuracy of our

  6. Spatiotemporal Variability of Land Surface Phenology in China from 2001–2014

    Directory of Open Access Journals (Sweden)

    Zhaohui Luo

    2017-01-01

    Full Text Available Land surface phenology is a highly sensitive and simple indicator of vegetation dynamics and climate change. However, few studies on spatiotemporal distribution patterns and trends in land surface phenology across different climate and vegetation types in China have been conducted since 2000, a period during which China has experienced remarkably strong El Niño events. In addition, even fewer studies have focused on changes of the end of season (EOS and length of season (LOS despite their importance. In this study, we used four methods to reconstruct Moderate Resolution Imaging Spectroradiometer (MODIS Enhanced Vegetation Index (EVI dataset and chose the best smoothing result to estimate land surface phenology. Then, the phenophase trends were analyzed via the Mann-Kendall method. We aimed to assess whether trends in land surface phenology have continued since 2000 in China at both national and regional levels. We also sought to determine whether trends in land surface phenology in subtropical or high altitude areas are the same as those observed in high latitude areas and whether those trends are uniform among different vegetation types. The result indicated that the start of season (SOS was progressively delayed with increasing latitude and altitude. In contrast, EOS exhibited an opposite trend in its spatial distribution, and LOS showed clear spatial patterns over this region that decreased from south to north and from east to west at a national scale. The trend of SOS was advanced at a national level, while the trend in Southern China and the Tibetan Plateau was opposite to that in Northern China. The transaction zone of the SOS within Northern China and Southern China occurred approximately between 31.4°N and 35.2°N. The trend in EOS and LOS were delayed and extended, respectively, at both national and regional levels except that of LOS in the Tibetan Plateau, which was shortened by delayed SOS onset more than by delayed EOS onset. The

  7. Spatial variability of surface fuels in treated and untreated ponderosa pine forests of the southern Rocky Mountains

    Science.gov (United States)

    Emma Vakili; Chad M. Hoffman; Robert E. Keane; Wade T. Tinkham; Yvette Dickinson

    2016-01-01

    There is growing consensus that spatial variability in fuel loading at scales down to 0.5 m may govern fire behaviour and effects. However, there remains a lack of understanding of how fuels vary through space in wildland settings. This study quantifies surface fuel loading and its spatial variability in ponderosa pine sites before and after fuels treatment in the...

  8. Goethite surface reactivity: III. Unifying arsenate adsorption behavior through a variable crystal face - Site density model

    Science.gov (United States)

    Salazar-Camacho, Carlos; Villalobos, Mario

    2010-04-01

    goethite, may be performed for each preparation either by experimental determination of site saturation by an index ion (e.g., chromate), or by achieving congruency of proton adsorption data with those of ideal goethites when plotted as percentage of proton-reactive ( lbond2 FeOH + lbond2 Fe 3OH) sites occupied. The surface arsenate complexes proposed additionally explained: (1) the higher affinity of goethite for As(V) than for Cr(VI) at high pH, and thus the gentle slope of the arsenate pH adsorption edges; and (2) the lower adsorption capacity for As(V) than for Cr(VI) at low pH on low-surface area goethites, through incomplete lbond2 FeOH site occupancy of As(V). The model is very promising as a practical means of predicting the adsorption behavior of arsenate on any goethite preparation, and may extend to predictive capabilities for adsorption behavior of many other relevant oxyanions, as well as for explaining differences in ligand-promoted surface transformation processes on goethite as a function of particle size.

  9. The influence of grazing on surface climatological variables of tallgrass prairie. Final Technical Report

    International Nuclear Information System (INIS)

    Seastedt, T.R.; Dyer, M.I.; Turner, C.L.

    1992-01-01

    Mass and energy exchange between most grassland canopies and the atmosphere are mediated by grazing activities. Ambient temperatures can be increased or decreased by grazers. Data have been assembled from simulated grazing experiments on Konza Prairie Research Natural Area and observations on adjacent pastures grazed by cattle show significant changes in primary production, nutrient content, and bidirectional reflectance characteristics as a function of grazing intensity. The purpose of this research was to provide algorithms that would allow incorporation of grazing effects into models of energy budgets using remote sensing procedures. The approach involved: (1) linking empirical measurements of plant biomass and grazing intensities to remotely sensed canopy reflectance, and (2) using a higher resolution, mechanistic grazing model to derive plant ecophysiological parameters that influence reflectance and other surface climatological variables

  10. Surface Variability of Short-wavelength Radiation and Temperature on Exoplanets around M Dwarfs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin; Tian, Feng [Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing 100084 (China); Wang, Yuwei [Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, QC H3A 0B9 (Canada); Dudhia, Jimy; Chen, Ming, E-mail: tianfengco@tsinghua.edu.cn [National Center for Atmospheric Research, Boulder, CO (United States)

    2017-03-10

    It is a common practice to use 3D General Circulation Models (GCM) with spatial resolution of a few hundred kilometers to simulate the climate of Earth-like exoplanets. The enhanced albedo effect of clouds is especially important for exoplanets in the habitable zones around M dwarfs that likely have fixed substellar regions and substantial cloud coverage. Here, we carry out mesoscale model simulations with 3 km spatial resolution driven by the initial and boundary conditions in a 3D GCM and find that it could significantly underestimate the spatial variability of both the incident short-wavelength radiation and the temperature at planet surface. Our findings suggest that mesoscale models with cloud-resolving capability be considered for future studies of exoplanet climate.

  11. Muscle conduction velocity, surface electromyography variables, and echo intensity during concentric and eccentric fatigue.

    Science.gov (United States)

    Gonzalez-Izal, Miriam; Lusa Cadore, Eduardo; Izquierdo, Mikel

    2014-03-01

    Concentric (CON) and eccentric (ECC) contractions may involve different mechanisms related to changes in sarcolemma status and the consequent alteration of action potential transmission along muscle fibers. Muscle conduction velocity (CV), surface electromyography signal (sEMG), muscle quality, and blood lactate concentrations were analyzed during CON and ECC actions. Compared with ECC, the CON protocol resulted in greater muscle force losses, blood lactate concentrations, and changes in sEMG parameters. Similar reductions in CV were detected in both protocols. Higher echo intensity values were observed 2 days after ECC due to greater muscle damage. The effects of the muscle damage produced by ECC exercise on the transmission of action potentials along muscle fibers (measured as the CV) may be comparable with the effects of hydrogen accumulation produced by CON exercise (related to greater lactate concentrations), which causes greater force loss and change in other sEMG variables during CON than during ECC actions.

  12. An analysis of surface air temperature trends and variability along the Andes

    Science.gov (United States)

    Franquist, Eric S.

    Climate change is difficult to study in mountainous regions such as the Andes since steep changes in elevation cannot always be resolved by climate models. However, it is important to examine temperature trends in this region as rises in surface air temperature are leading to the melting of tropical glaciers. Local communities rely on the glacier-fed streamflow to get their water for drinking, irrigation, and livestock. Moreover, communities also rely on the tourism of hikers who come to the region to view the glaciers. As the temperatures increase, these glaciers are no longer in equilibrium with their current climate and are receding rapidly and decreasing the streamflow. This thesis examines surface air temperature from 858 weather stations across Ecuador, Peru, and Chile in order to analyze changes in trends and variability. Three time periods were studied: 1961--1990, 1971--2000, and 1981--2010. The greatest warming occurred during the period of 1971--2000 with 92% of the stations experiencing positive trends with a mean of 0.24°C/decade. There was a clear shift toward cooler temperatures at all latitudes and below elevations of 500 m during the most recent time period studied (1981--2010). Station temperatures were more strongly correlated with the El Nino Southern Oscillation (ENSO), than the Pacific Decadal Oscillation (PDO), and the Southern Annular Mode (SAM). A principal component analysis confirmed ENSO as the main contributor of variability with the most influence in the lower latitudes. There were clear multidecadal changes in correlation strength for the PDO. The PDO contributed the most to the increases in station temperature trends during the 1961--1990 period, consistent with the PDO shift to the positive phase in the middle of this period. There were many strong positive trends at individual stations during the 1971--2000 period; however, these trends could not fully be attributed to ENSO, PDO, or SAM, indicating anthropogenic effects of

  13. Prevalence and genetic variability of Plesiomonas shigelloides in temperate climate surface waters of the Pannonian Plain

    Directory of Open Access Journals (Sweden)

    Petrušić Milivoje

    2018-01-01

    Full Text Available Plesiomonas shigelloides, a Gram-negative bacterium and the causative agent of intestinal diseases and extraintestinal infections in humans and animals, is most frequently found in aquatic environments in tropical or subtropical areas. The present study was designed to establish the prevalence and genetic variability of P. shigelloides in surface waters (lakes, rivers, ponds, inlets and canals located in a temperate climate zone, namely the Pannonian Plain of the northern part of Serbia and southern part of Hungary. The strains were isolated directly by plating samples on inositol-brilliant green-bile agar with neutral red or phenol red as indicators. Our results indicate that phenol red effectively facilitates differentiation of P. shigelloides from other bacteria. A number of samples were enriched using alkaline peptone water broth, peptone inositolbile broth and tetrathionate broth. The recovery of the isolates was more successful with the first medium. Out of a total of 51 water samples collected from 28 different locations, 22 samples (43.1% were found positive for P. shigelloides. Among the 37 isolated strains, 34 were from lakes (Šatrinci, Ludaš, Panonija, Krivaja, Pecs, Kapetanski rit, Pavlovci, Kovacsszenaja, Dobrodol, Vranjaš, Borkovac, Hermann Otto, Sot, Šelevrenac, Zobnatica, Palić, Orfui, Jarkovci, Čonoplja and 3 were from rivers (Danube, Sava. The strains were identified by phenotypic characteristic or by the VITEK2 system and confirmed by PCR using 23S rRNA species-specific oligos. The strains showed a high genetic variability, displaying a variety of RAPD profiles. Our results reveal for the first time a high prevalence of genetically diverse P. shigelloides populations in surface waters located in the temperate climate of central and southeastern Europe. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI 172058

  14. Optimization of Process Variables for Insulation Coating of Conductive Particles by Response Surface Methodology

    International Nuclear Information System (INIS)

    Sim, Chol-Ho

    2016-01-01

    The powder core, conventionally fabricated from iron particles coated with insulator, showed large eddy current loss under high frequency, because of small specific resistance. To overcome the eddy current loss, the increase in the specific resistance of powder cores was needed. In this study, copper oxide coating onto electrically conductive iron particles was performed using a planetary ball mill to increase the specific resistance. Coating factors were optimized by the Response surface methodology. The independent variables were the CuO mass fraction, mill revolution number, coating time, ball size, ball mass and sample mass. The response variable was the specific resistance. The optimization of six factors by the fractional factorial design indicated that CuO mass fraction, mill revolution number, and coating time were the key factors. The levels of these three factors were selected by the three-factors full factorial design and steepest ascent method. The steepest ascent method was used to approach the optimum range for maximum specific resistance. The Box-Behnken design was finally used to analyze the response surfaces of the screened factors for further optimization. The results of the Box-Behnken design showed that the CuO mass fraction and mill revolution number were the main factors affecting the efficiency of coating process. As the CuO mass fraction increased, the specific resistance increased. In contrast, the specific resistance increased with decreasing mill revolution number. The process optimization results revealed a high agreement between the experimental and the predicted data (Adj-R2=0.944). The optimized CuO mass fraction, mill revolution number, and coating time were 0.4, 200 rpm, and 15 min, respectively. The measured value of the specific resistance of the coated pellet under the optimized conditions of the maximum specific resistance was 530 kΩ·cm

  15. Optimization of Process Variables for Insulation Coating of Conductive Particles by Response Surface Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Chol-Ho [Sangji University, Wonju (Korea, Republic of)

    2016-02-15

    The powder core, conventionally fabricated from iron particles coated with insulator, showed large eddy current loss under high frequency, because of small specific resistance. To overcome the eddy current loss, the increase in the specific resistance of powder cores was needed. In this study, copper oxide coating onto electrically conductive iron particles was performed using a planetary ball mill to increase the specific resistance. Coating factors were optimized by the Response surface methodology. The independent variables were the CuO mass fraction, mill revolution number, coating time, ball size, ball mass and sample mass. The response variable was the specific resistance. The optimization of six factors by the fractional factorial design indicated that CuO mass fraction, mill revolution number, and coating time were the key factors. The levels of these three factors were selected by the three-factors full factorial design and steepest ascent method. The steepest ascent method was used to approach the optimum range for maximum specific resistance. The Box-Behnken design was finally used to analyze the response surfaces of the screened factors for further optimization. The results of the Box-Behnken design showed that the CuO mass fraction and mill revolution number were the main factors affecting the efficiency of coating process. As the CuO mass fraction increased, the specific resistance increased. In contrast, the specific resistance increased with decreasing mill revolution number. The process optimization results revealed a high agreement between the experimental and the predicted data (Adj-R2=0.944). The optimized CuO mass fraction, mill revolution number, and coating time were 0.4, 200 rpm, and 15 min, respectively. The measured value of the specific resistance of the coated pellet under the optimized conditions of the maximum specific resistance was 530 kΩ·cm.

  16. Optimization and Modeling of Process Variables of Biodiesel Production from Marula Oil using Response Surface Methodology

    International Nuclear Information System (INIS)

    Enweremadu, C. C.; Rutto, H. L.

    2015-01-01

    This paper presents an optimization study in the production of biodiesel production from Marula oil. The study was carried out using a central composite design of experiments under response surface methodology. A mathematical model was developed to correlate the transesterification process variables to biodiesel yield. The transesterification reaction variables were methanol to oil ratio, x /sub 1/ (10-50 wt percentage), reaction time, x /sub 2/ (30-90 min), reaction temperature, x /sub 3/ (30-90 Degree C) stirring speed, x /sub 4/ (100-400 rpm) and amount of catalyst, x /sub 5/ (0.5-1.5 g). The optimum conditions for the production of the biodiesel were found to be methanol to oil ratio (29.43 wt percentage), reaction time (59.17 minutes), reaction temperature (58.80 Degree C), stirring speed (325 rpm) and amount of catalyst (1.02 g). The optimum yield of biodiesel that can be produced was 95 percentage. The results revealed that the crucial fuel properties of the biodiesel produced at the optimum conditions met the ASTM biodiesel specifications. (author)

  17. MULTI-EPOCH IMAGING POLARIMETRY OF THE SiO MASERS IN THE EXTENDED ATMOSPHERE OF THE MIRA VARIABLE TX CAM

    International Nuclear Information System (INIS)

    Kemball, Athol J.; Diamond, Philip J.; Gonidakis, Ioannis; Mitra, Modhurita; Yim, Kijeong; Pan, K.-C.; Chiang, H.-F.

    2009-01-01

    We present a time series of synoptic images of the linearly polarized v = 1, J = 1-0 SiO maser emission toward the Mira variable, TX Cam. These data comprise 43 individual epochs at an approximate biweekly sampling over an optical pulsation phase range of φ = 0.68 to φ = 1.82. The images have an angular resolution of ∼500 μas and were obtained using the Very Long Baseline Array (VLBA), operating in the 43 GHz band in spectral-line, polarization mode. We have previously published the total intensity time series for this pulsation phase range; this paper serves to present the linearly polarized image sequence and an associated animation representing the evolution of the linear polarization morphology over time. We find a predominantly tangential polarization morphology, a high degree of persistence in linear polarization properties over individual component lifetimes, and stronger linear polarization in the inner projected shell than at larger projected shell radii. We present an initial polarization proper motion analysis examining the possible dynamical influence of magnetic fields in component motions in the extended atmospheres of late-type, evolved stars.

  18. Sea Surface Height Variability and Eddy Statistical Properties in the Red Sea

    KAUST Repository

    Zhan, Peng

    2013-05-01

    Satellite sea surface height (SSH) data over 1992-2012 are analyzed to study the spatial and temporal variability of sea level in the Red Sea. Empirical orthogonal functions (EOF) analysis suggests the remarkable seasonality of SSH in the Red Sea, and a significant correlation is found between SSH variation and seasonal wind cycle. A winding-angle based eddy identification algorithm is employed to derive the mesoscale eddy information from SSH data. Totally more than 5500 eddies are detected, belonging to 2583 eddy tracks. Statistics suggest that eddies generate over the entire Red Sea, with two regions in the central basin of high eddy frequency. 76% of the detected eddies have a radius ranging from 40km to 100km, of which both intensity and absolute vorticity decrease with eddy radius. The average eddy lifespan is about 5 weeks, and eddies with longer lifespan tend to have larger radius but less intensity. Different deformation rate exists between anticyclonic eddies (AEs) and cyclonic eddies (CEs), those eddies with higher intensity appear to be less deformed and more circular. Inspection of the 84 long-lived eddies suggests the AEs tend to move a little more northward than CEs. AE generation during summer is obviously lower than that during other seasons, while CE generation is higher during spring and summer. Other features of AEs and CEs are similar with both vorticity and intensity reaching the summer peaks in August and winter peaks in January. Inter-annual variability reveals that the eddies in the Red Sea are isolated from the global event. The eddy property tendencies are different from the south and north basin, both of which exhibit a two-year cycle. Showing a correlation coefficient of -0.91, Brunt–Väisälä frequency is negatively correlated with eddy kinetic energy (EKE), which results from AE activities in the high eddy frequency region. Climatological vertical velocity shear variation is identical with EKE except in the autumn, suggesting the

  19. Adriatic Sea surface temperature and ocean colour variability during the MFSPP

    Directory of Open Access Journals (Sweden)

    E. Böhm

    2003-01-01

    Full Text Available Two years and six months of night-time Advanced Very High Resolution Radiometer (AVHRR sea surface temperature (SST and daytime Sea viewing Wide Field of view Sensor (SeaWiFS data collected during the MFSPP have been used to examine spatial and temporal variability of SST and chlorophyll (Chl in the Adriatic Sea. Flows along the Albanian and the Italian coasts can be distinguished year-round in the monthly averaged Chl but only in the colder months in the monthly averaged SST’s. The Chl monthly-averaged fields supply less information on circulation features away from coastal boundaries and where conditions are generally oligotrophic, except for the early spring bloom in the Southern Adriatic Gyre. To better characterise the year-to-year and seasonal variability, exploratory data analysis techniques, particularly the plotting of multiple Chl-SST histograms, are employed to make joint quantitative use of monthly-averaged fields. Modal water mass (MW, corresponding to the Chl-SST pairs in the neighbourhood of the maximum of each monthly histogram, are chosen to represent the temporal and spatial evolution of the prevalent processes and their variability in the Adriatic Sea. Over an annual cycle, the MW followed a triangular path with the most pronounced seasonal and interannual variations in both Chl-SST properties and spatial distributions of the MW in the colder part of the year. The winter of 1999 is the colder (by at least 0.5°C and most eutrophic (by 0.2 mg/m 3. The fall of the year 2000 is characterised by the lack of cooling in the month of November that was observed in the previous year. In addition to characterising the MW, the two-dimensional histogram technique allows a distinction to be made between different months in terms of the spread of SST values at a given Chl concentration. During spring and summer, the spread is minimal indicating surface homothermal conditions. In fall and winter, on the other hand, a spread of points

  20. Consciousness extended

    DEFF Research Database (Denmark)

    Carrara-Augustenborg, Claudia

    2012-01-01

    There is no consensus yet regarding a conceptualization of consciousness able to accommodate all the features of such complex phenomenon. Different theoretical and empirical models lend strength to both the occurrence of a non-accessible informational broadcast, and to the mobilization of specific...... brain areas responsible for the emergence of the individual´s explicit and variable access to given segments of such broadcast. Rather than advocating one model over others, this chapter proposes to broaden the conceptualization of consciousness by letting it embrace both mechanisms. Within...... such extended framework, I propose conceptual and functional distinctions between consciousness (global broadcast of information), awareness (individual´s ability to access the content of such broadcast) and unconsciousness (focally isolated neural activations). My hypothesis is that a demarcation in terms...

  1. Spatiotemporal variability of Canadian High Arctic glacier surface albedo from MODIS data, 2001-2016

    Science.gov (United States)

    Mortimer, Colleen A.; Sharp, Martin

    2018-02-01

    Inter-annual variations and longer-term trends in the annual mass balance of glaciers in Canada's Queen Elizabeth Islands (QEI) are largely attributable to changes in summer melt. The largest source of melt energy in the QEI in summer is net shortwave radiation, which is modulated by changes in glacier surface albedo. We used measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to investigate large-scale spatial patterns, temporal trends, and variability in the summer surface albedo of QEI glaciers from 2001 to 2016. Mean summer black-sky shortwave broadband albedo (BSA) decreased at a rate of 0.029±0.025 decade-1 over that period. Larger reductions in BSA occurred in July (-0.050±0.031 decade-1). No change in BSA was observed in either June or August. Most of the decrease in BSA, which was greatest at lower elevations around the margins of the ice masses, occurred between 2007 and 2012, when mean summer BSA was anomalously low. The first principal component of the 16-year record of mean summer BSA was well correlated with the mean summer North Atlantic Oscillation index, except in 2006, 2010, and 2016, when the mean summer BSA appears to have been dominated by the August BSA. During the period 2001-2016, the mean summer land surface temperature (LST) over the QEI glaciers and ice caps increased by 0.049±0.038 °C yr-1, and the BSA record was negatively correlated (r: -0.86) with the LST record, indicative of a positive ice-albedo feedback that would increase rates of mass loss from the QEI glaciers.

  2. Empirical downscaling of atmospheric key variables above a tropical glacier surface (Cordillera Blanca, Peru)

    Science.gov (United States)

    Hofer, M.; Kaser, G.; Mölg, T.; Juen, I.; Wagnon, P.

    2009-04-01

    Glaciers in the outer tropical Cordillera Blanca (Peru, South America) are of major socio-economic importance, since glacier runoff represents the primary water source during the dry season, when little or no rainfall occurs. Due to their location at high elevations, the glaciers moreover provide important information about climate change in the tropical troposphere, where measurements are sparse. This study targets the local reconstruction of air temperature, specific humidity and wind speed above the surface of an outer tropical glacier from NCEP/NCAR reanalysis data as large scale predictors. Since a farther scope is to provide input data for process based glacier mass balance modelling, the reconstruction pursues a high temporal resolution. Hence an empirical downscaling scheme is developed, based on a few years' time series of hourly observations from automatic weather stations, located at the glacier Artesonraju and nearby moraines (Northern Cordillera Blanca). Principal component and multiple regression analyses are applied to define the appropriate spatial downscaling domain, suitable predictor variables, and the statistical transfer functions. The model performance is verified using an independent data set. The best predictors are lower tropospheric air temperature and specific humidity, at reanalysis model grid points that represent the Bolivian Altiplano, located in the South of the Cordillera Blanca. The developed downscaling model explaines a considerable portion (more than 60%) of the diurnal variance of air temperature and specific humidity at the moraine stations, and air temperature above the glacier surface. Specific humidity above the glacier surface, however, can be reconstructed well in the seasonal, but not in the required diurnal time resolution. Wind speed can only be poorly determined by the large scale predictors (r² lower than 0.3) at both sites. We assume a complex local interaction between valley and glacier wind system to be the main

  3. Spatial and temporal variability of surface water pollution in the Mekong Delta, Vietnam.

    Science.gov (United States)

    Wilbers, Gert-Jan; Becker, Mathias; Nga, La Thi; Sebesvari, Zita; Renaud, Fabrice G

    2014-07-01

    Surface water pollution in the Vietnamese Mekong Delta (MD) could threaten human, animal and ecosystem health given the fact that this water source is intensively used for drinking, irrigation and domestic services. We therefore determined the levels of pollution by organic pollutants, salts, metals and microbial indicators by (bi)monthly monitoring of canals between November 2011 and July 2012 at 32 sampling locations, representing fresh and saline/brackish environments. The results were compared with national water quality guidelines, between the studied regions and with water quality data from main waterways. Key factors explaining the observed levels of pollution in surface water were identified through principal component analysis (PCA). Temporal variations due to tidal regime and seasonality were also assessed. Based on regression models, the spatial variability of five water quality parameters was visualized using GIS based maps. Results indicate that pH (max. 8.6), turbidity (max. 461 FTU), maximum concentrations of ammonium (14.7 mg L(-1)), arsenic (44.1 μg L(-1)), barium (157.5 μg L(-1)), chromium (84.7 μg L(-1)), mercury (45.5 μg L(-1)), manganese (1659.7 μg L(-1)), aluminum (14.5 mg L(-1)), iron (17.0 mg L(-1)) and the number of Escherichia coli (87,000 CFU 100 mL(-1)) and total coliforms (2,500,000 CFU 100 mL(-1)) in canals exceed the thresholds set by Vietnamese quality guidelines for drinking and domestic purposes. The PCA showed that i) urbanization; ii) metal leaching from soils; iii) aquaculture; and iv) tidal regime explain 85% of the variance of surface water quality attributes. Significant differences in water quality were found due to daily tidal regime and as a result of seasonality. Surface water quality maps for dissolved oxygen, ammonium, ortho-phosphate, manganese and total coliforms were developed to highlight hot-spot areas of pollution. The results of this study can assist policy makers in developing water management strategies

  4. Coupled ocean-atmosphere surface variability and its climate impacts in the tropical Atlantic region

    Science.gov (United States)

    Fontaine, B.; Janicot, Serge; Roucou, P.

    This study examines time evolution and statistical relationships involving the two leading ocean-atmosphere coupled modes of variability in the tropical Atlantic and some climate anomalies over the tropical 120°W-60°W region using selected historical files (75-y near global SSTs and precipitation over land), more recent observed data (30-y SST and pseudo wind stress in the tropical Atlantic) and reanalyses from the US National Centers for Environmental Prediction (NCEP/NCAR) reanalysis System on the period 1968-1997: surface air temperature, sea level pressure, moist static energy content at 850 hPa, precipitable water and precipitation. The first coupled mode detected through singular value decomposition of the SST and pseudo wind-stress data over the tropical Atlantic (30°N-20°S) expresses a modulation in the thermal transequatorial gradient of SST anomalies conducted by one month leading wind-stress anomalies mainly in the tropical north Atlantic during northern winter and fall. It features a slight dipole structure in the meridional plane. Its time variability is dominated by a quasi-decadal signal well observed in the last 20-30 ys and, when projected over longer-term SST data, in the 1920s and 1930s but with shorter periods. The second coupled mode is more confined to the south-equatorial tropical Atlantic in the northern summer and explains considerably less wind-stress/SST cross-covariance. Its time series features an interannual variability dominated by shorter frequencies with increased variance in the 1960s and 1970s before 1977. Correlations between these modes and the ENSO-like Nino3 index lead to decreasing amplitude of thermal anomalies in the tropical Atlantic during warm episodes in the Pacific. This could explain the nonstationarity of meridional anomaly gradients on seasonal and interannual time scales. Overall the relationships between the oceanic component of the coupled modes and the climate anomaly patterns denote thermodynamical

  5. Effect of Ionic Correlations on the Surface Forces in Thin Liquid Films: Influence of Multivalent Coions and Extended Theory

    Directory of Open Access Journals (Sweden)

    Krassimir D. Danov

    2016-03-01

    Full Text Available Experimental data for the disjoining pressure of foam films stabilized by anionic surfactant in the presence of 1:1, 1:2, 1:3, and 2:2 electrolytes: NaCl, Na2SO4, Na3Citrate, and MgSO4 are reported. The disjoining pressure predicted by the Derjaguin-Landau-Verwey-Overbeek (DLVO theory coincides with the experimental data in the case of a 1:1 electrolyte, but it is considerably greater than the measured pressure in all other cases. The theory is extended to account for the effects of ionic correlations and finite ionic radii. Original analytical expressions are derived for the local activity coefficient, electrostatic disjoining pressure, and asymptotic screening parameter. With the same parameter of counterion binding as for a 1:1 electrolyte, the curves predicted by the extended theory are in perfect agreement with the experimental data for 1:2 and 1:3 electrolytes. In comparison with the DLVO theory, the effect of ionic correlations leads to more effective screening of electrostatic interactions, and lower electric potential and counterion concentrations in the film’s midplane, resulting in lower disjoining pressure, as experimentally observed. The developed theory is applicable to both multivalent coions and multivalent counterions. Its application could remove some discrepancies between theory and experiment observed in studies with liquid films from electrolyte solutions.

  6. Multidrug-Resistant and Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Dutch Surface Water and Wastewater.

    Directory of Open Access Journals (Sweden)

    Hetty Blaak

    Full Text Available The goal of the current study was to gain insight into the prevalence and concentrations of antimicrobial resistant (AMR Escherichia coli in Dutch surface water, and to explore the role of wastewater as AMR contamination source.The prevalence of AMR E. coli was determined in 113 surface water samples obtained from 30 different water bodies, and in 33 wastewater samples obtained at five health care institutions (HCIs, seven municipal wastewater treatment plants (mWWTPs, and an airport WWTP. Overall, 846 surface water and 313 wastewater E. coli isolates were analysed with respect to susceptibility to eight antimicrobials (representing seven different classes: ampicillin, cefotaxime, tetracycline, ciprofloxacin, streptomycin, sulfamethoxazole, trimethoprim, and chloramphenicol.Among surface water isolates, 26% were resistant to at least one class of antimicrobials, and 11% were multidrug-resistant (MDR. In wastewater, the proportions of AMR/MDR E. coli were 76%/62% at HCIs, 69%/19% at the airport WWTP, and 37%/27% and 31%/20% in mWWTP influents and effluents, respectively. Median concentrations of MDR E. coli were 2.2×10(2, 4.0×10(4, 1.8×10(7, and 4.1×10(7 cfu/l in surface water, WWTP effluents, WWTP influents and HCI wastewater, respectively. The different resistance types occurred with similar frequencies among E. coli from surface water and E. coli from municipal wastewater. By contrast, among E. coli from HCI wastewater, resistance to cefotaxime and resistance to ciprofloxacin were significantly overrepresented compared to E. coli from municipal wastewater and surface water. Most cefotaxime-resistant E. coliisolates produced ESBL. In two of the mWWTP, ESBL-producing variants were detected that were identical with respect to phylogenetic group, sequence type, AMR-profile, and ESBL-genotype to variants from HCI wastewater discharged onto the same sewer and sampled on the same day (A1/ST23/CTX-M-1, B23/ST131/CTX-M-15, D2/ST405/CTX-M-15.In

  7. Effects of radiation and thermal diffusivity on heat transfer over a stretching surface with variable heat flux

    International Nuclear Information System (INIS)

    Seddeek, M.A.; Abdelmeguid, M.S.

    2006-01-01

    The effect of radiation and thermal diffusivity on heat transfer over a stretching surface with variable heat flux has been studied. The thermal diffusivity is assumed to vary as a linear function of temperature. The governing partial differential equations have been transformed to ordinary differential equations. The exact analytical solution for the velocity and the numerical solution for the temperature field are given. Numerical solutions are obtained for different values of variable thermal diffusivity, radiation, temperature parameter and Prandtl number

  8. Reversibility and intermediate steps as key tools for the growth of extended ordered polymers via on-surface synthesis

    Science.gov (United States)

    Di Giovannantonio, Marco; Contini, Giorgio

    2018-03-01

    Surface-confined polymerization is a bottom-up strategy to create one- and two-dimensional covalent organic nanostructures with a π-conjugated backbone, which are suitable to be employed in real-life electronic devices, due to their high mechanical resistance and electronic charge transport efficiency. This strategy makes it possible to change the properties of the final nanostructures by a careful choice of the monomer architecture (i.e. of its constituent atoms and their spatial arrangement). Several chemical reactions have been proven to form low-dimensional polymers on surfaces, exploiting a variety of precursors in combination with metal (e.g. Cu, Ag, Au) and insulating (e.g. NaCl, CaCO3) surfaces. One of the main challenges of such an approach is to obtain nanostructures with long-range order, to boost the conductance performances of these materials. Most of the exploited chemical reactions use irreversible coupling between the monomers and, as a consequence, the resulting structures often suffer from poor order and high defect density. This review focuses on the state-of-the-art surface-confined polymerization reactions, with particular attention paid to reversible coupling pathways and irreversible processes including intermediate states, which are key aspects to control to increase the order of the final nanostructure.

  9. Extending and refining the mass surface around $^{208}$Pb by high-precision Penning-trap mass spectrometry with ISOLTRAP

    CERN Multimedia

    Herfurth, F; Stora, T; Blaum, K; Beck, D; Kowalska, M; Schwarz, S; Stanja, J; Herlert, A J; Yamaguchi, T

    We propose high-precision mass spectrometry of nuclides around the doubly magic $^{208}$Pb. On the neutron-rich side, we aim to extend the knowledge of Fr, At, Hg, and Au masses to study the robustness of the N = 126 shell closure and to provide mass data necessary for modeling the rapid-neutron-capture process. On the proton-rich side, we aim at high-resolution mass spectrometry of selected Au, At, and Fr isotopes to verify the predicted existence of very low-lying isomeric states. The proposal will make use of newly-available laser-ionization schemes for Au and At. Finally, the recently implemented multi-reflection time-of-flight mass separator for auxiliary isobaric purification now allows measurements which were not feasible before.

  10. Thermal infrared imagery as a tool for analysing the variability of surface saturated areas at various temporal and spatial scales

    Science.gov (United States)

    Glaser, Barbara; Antonelli, Marta; Pfister, Laurent; Klaus, Julian

    2017-04-01

    Surface saturated areas are important for the on- and offset of hydrological connectivity within the hillslope-riparian-stream continuum. This is reflected in concepts such as variable contributing areas or critical source areas. However, we still lack a standardized method for areal mapping of surface saturation and for observing its spatiotemporal variability. Proof-of-concept studies in recent years have shown the potential of thermal infrared (TIR) imagery to record surface saturation dynamics at various temporal and spatial scales. Thermal infrared imagery is thus a promising alternative to conventional approaches, such as the squishy boot method or the mapping of vegetation. In this study we use TIR images to investigate the variability of surface saturated areas at different temporal and spatial scales in the forested Weierbach catchment (0.45 km2) in western Luxembourg. We took TIR images of the riparian zone with a hand-held FLIR infrared camera at fortnightly intervals over 18 months at nine different locations distributed over the catchment. Not all of the acquired images were suitable for a derivation of the surface saturated areas, as various factors influence the usability of the TIR images (e.g. temperature contrasts, shadows, fog). Nonetheless, we obtained a large number of usable images that provided a good insight into the dynamic behaviour of surface saturated areas at different scales. The images revealed how diverse the evolution of surface saturated areas can be throughout the hydrologic year. For some locations with similar morphology or topography we identified diverging saturation dynamics, while other locations with different morphology / topography showed more similar behaviour. Moreover, we were able to assess the variability of the dynamics of expansion / contraction of saturated areas within the single locations, which can help to better understand the mechanisms behind surface saturation development.

  11. Modeling the South American regional smoke plume: aerosol optical depth variability and surface shortwave flux perturbation

    Directory of Open Access Journals (Sweden)

    N. E. Rosário

    2013-03-01

    Full Text Available Intra-seasonal variability of smoke aerosol optical depth (AOD and downwelling solar irradiance at the surface during the 2002 biomass burning season in South America was modeled using the Coupled Chemistry-Aerosol-Tracers Transport model with the Brazilian developments on the Regional Atmospheric Modeling System (CCATT-BRAMS. Measurements of total and fine mode fraction (FMF AOD from the AErosol RObotic NETwork (AERONET and solar irradiance at the surface from the Solar Radiation Network (SolRad-NET were used to evaluate model results. In general, the major features associated with AOD evolution over the southern part of the Amazon basin and cerrado ecosystem are captured by the model. The main discrepancies were found for high aerosol loading events. In the northeastern portion of the Amazon basin the model systematically underestimated total AOD, as expected, since smoke contribution is not dominant as it is in the southern portion and emissions other than smoke were not considered in the simulation. Better agreement was obtained comparing the model results with observed FMF AOD, which pointed out the relevance of coarse mode aerosol emission in that region. Likewise, major discrepancies over cerrado during high AOD events were found to be associated with coarse mode aerosol omission in our model. The issue of high aerosol loading events in the southern part of the Amazon was related to difficulties in predicting the smoke AOD field, which was discussed in the context of emissions shortcomings. The Cuiabá cerrado site was the only one where the highest quality AERONET data were unavailable for both total and FMF AOD. Thus, lower quality data were used. Root-mean-square error (RMSE between the model and observed FMF AOD decreased from 0.34 to 0.19 when extreme AOD events (FMF AOD550 nm ≥ 1.0 and Cuiabá were excluded from the analysis. Downward surface solar irradiance comparisons also followed similar trends when extreme AOD were excluded

  12. Cortical thickness, surface area, and volume of the brain reward system in alcohol dependence: relationships to relapse and extended abstinence.

    Science.gov (United States)

    Durazzo, Timothy C; Tosun, Duygu; Buckley, Shannon; Gazdzinski, Stefan; Mon, Anderson; Fryer, Susanna L; Meyerhoff, Dieter J

    2011-06-01

    At least 60% of those treated for an alcohol use disorder will relapse. Empirical study of the integrity of the brain reward system (BRS) is critical to understanding the mechanisms of relapse as this collection of circuits is implicated in the development and maintenance of all forms of addictive disorders. This study compared thickness, surface area, and volume in neocortical components of the BRS among nonsmoking light-drinking controls (controls), individuals who remained abstinent and those who relapsed after treatment. Seventy-five treatment-seeking alcohol-dependent individuals (abstinent for 7±3 days) and 43 controls completed 1.5T proton magnetic resonance imaging studies. Parcellated morphological data were obtained for following bilateral components of the BRS: rostral and caudal anterior cingulate cortex, insula, medial and lateral orbitofrontal cortex (OFC), rostral and caudal middle and superior frontal gyri, amygdala and hippocampus as well as for 26 other bilateral neocortical regions. Alcohol-dependent participants were followed over 12-months after baseline study and were classified as abstainers (no alcohol consumption; n=24) and relapsers (any alcohol consumption; n=51) at follow-up. Relapsers and abstainers demonstrated lower cortical thickness in the vast majority of BRS regions as well as lower global thickness compared to controls. Relapsers had lower total BRS surface area than both controls and abstainers, but abstainers were not significantly different from controls on any surface area measure. Relapsers demonstrated lower volumes than controls in the majority of regions, while abstainers showed lower volumes than controls in the superior frontal gyrus, insula, amygdala, and hippocampus, bilaterally. Relapsers exhibited smaller volumes than abstainers in the right rostral middle and caudal middle frontal gyri and the lateral OFC, bilaterally. In relapsers, lower baseline volumes and surface areas in multiple regions were associated with

  13. Northern South China Sea Surface Circulation and its Variability Derived by Combining Satellite Altimetry and Surface Drifter Data

    Directory of Open Access Journals (Sweden)

    N. Peter Benny

    2015-01-01

    Full Text Available The present study analyses the mean and seasonal mesoscale surface circulation of the Northern South China Sea (NSCS and determines the influence of El Niño/SouthernNiño/Southern Oscillation (ENSO. High resolution Eulerian velocity field is derived by combining the available satellite tracked surface drifter data with satellite altimetry during 1993 - 2012. The wind driven current is computed employing the weekly ocean surface mean wind fields derived from the scatterometers on board ERS 1/2, QuikSCAT and ASCAT. The derived mean velocity field exhibits strong boundary currents and broad zonal flow across NSCS. The anomalous field is quite strong in the southern part and the Seasonal circulation clearly depicts the monsoonal forcing. Eddy Kinetic Energy (EKE distribution and its spatial and temporal structures are determined employing Empirical Orthogonal Function (EOF analysis. The ENSO influence on NSCS surface circulation has been analyzed using monthly absolute geostrophic velocity fields during 1996 - 1999.

  14. Visualisation of variable binding pockets on protein surfaces by probabilistic analysis of related structure sets

    Directory of Open Access Journals (Sweden)

    Ashford Paul

    2012-03-01

    conserved occurrence of surface pockets at the active and regulatory sites; ii a simulated ensemble of unliganded Bcl2 structures reveals extensions of a known ligand-binding pocket not apparent in the apo crystal structure; iii visualisations of interleukin-2 and its homologues highlight conserved pockets at the known receptor interfaces and regions whose conformation is known to change on inhibitor binding. Conclusions Through post-processing of the output of a variety of pocket prediction software, Provar provides a flexible approach to the analysis and visualization of the persistence or variability of pockets in sets of related protein structures.

  15. Visualisation of variable binding pockets on protein surfaces by probabilistic analysis of related structure sets.

    Science.gov (United States)

    Ashford, Paul; Moss, David S; Alex, Alexander; Yeap, Siew K; Povia, Alice; Nobeli, Irene; Williams, Mark A

    2012-03-14

    Protein structures provide a valuable resource for rational drug design. For a protein with no known ligand, computational tools can predict surface pockets that are of suitable size and shape to accommodate a complementary small-molecule drug. However, pocket prediction against single static structures may miss features of pockets that arise from proteins' dynamic behaviour. In particular, ligand-binding conformations can be observed as transiently populated states of the apo protein, so it is possible to gain insight into ligand-bound forms by considering conformational variation in apo proteins. This variation can be explored by considering sets of related structures: computationally generated conformers, solution NMR ensembles, multiple crystal structures, homologues or homology models. It is non-trivial to compare pockets, either from different programs or across sets of structures. For a single structure, difficulties arise in defining particular pocket's boundaries. For a set of conformationally distinct structures the challenge is how to make reasonable comparisons between them given that a perfect structural alignment is not possible. We have developed a computational method, Provar, that provides a consistent representation of predicted binding pockets across sets of related protein structures. The outputs are probabilities that each atom or residue of the protein borders a predicted pocket. These probabilities can be readily visualised on a protein using existing molecular graphics software. We show how Provar simplifies comparison of the outputs of different pocket prediction algorithms, of pockets across multiple simulated conformations and between homologous structures. We demonstrate the benefits of use of multiple structures for protein-ligand and protein-protein interface analysis on a set of complexes and consider three case studies in detail: i) analysis of a kinase superfamily highlights the conserved occurrence of surface pockets at the active

  16. Extended objects

    International Nuclear Information System (INIS)

    Creutz, M.

    1976-01-01

    After some disconnected comments on the MIT bag and string models for extended hadrons, I review current understanding of extended objects in classical conventional relativistic field theories and their quantum mechanical interpretation

  17. TEM and CTX-M extended-spectrum beta-lactamase in Klebsiella spp and Escherichia coli isolates from inanimate surfaces of hospital environments

    OpenAIRE

    Rivera-Jacinto, Marco; Facultad de Ciencias de la Salud, Universidad Nacional de Cajamarca. Cajamarca, Perú.; Rodríguez-Ulloa, Claudia; Facultad de Ciencias de la Salud, Universidad Nacional de Cajamarca. Cajamarca, Perú.; Flores Clavo, René; Hospital Regional de Lambayeque. Lambayeque, Perú.; Serquén López, Luis; Hospital Regional de Lambayeque. Lambayeque, Perú.; Arce Gil, Zhandra; Universidad Católica Santo Toribio de Mogrovejo. Lambayeque, Perú.

    2015-01-01

    The aim of the study was to determine the genotype of 15 ESBL strains of Enterobacteriaceae resistant to beta-lactams, isolated from inanimate surfaces and phenotypically characterized as producing extended-spectrum beta-lactamase. After evaluation and screening of the bacterial strains, a PCR was conducted to amplify fragments of 1078 bp and 544 bp corresponding to type TEM and CTX-M ESBL. Eleven strains presented both fragments at the time and only three had blaCTX-M. In conclusion, the pre...

  18. Variability of the Surface Meteorological Fields over Eurasia for the Recent 30 Years

    International Nuclear Information System (INIS)

    Basharin, D.V.

    2009-10-01

    On the basis of the Japanese reanalysis (JRA25) dataset (1979-2008), linear trends, interannual to decadal variability of the sea level pressure (SLP), surface air temperature (SAT) and precipitation fields over the Eurasian region have been studied. For the recent 30 years there are only significant positive linear trends of SAT in the northwestern part of the Eurasia/eastern Asia in winter and central Europe in summer. Areas with significant negative trends of SAT are absent. For precipitation field there are no significant tendencies except for the significantly positive area over England both in winter and in summer time. In winter, there are two areas with the opposite SLP tendencies: insignificant negative (to the north of 45-50N) and significant positive (to the south of 45-50N) one. These trends could be accompanied by the corresponding tendencies bee-hive reproduction and honey production in different regions of Ukraine. Space-time patterns of the first, second and third EOF of the fields under study are mainly determined by the NAO and in the less extent by the SO (only in spring-summer). It was found that the leading modes become more contributive over the Eurasia for the last 30 years comparing with NCEP data for the previous period (1950-2001). It could imply that an internal signal of the ocean-atmosphere system, which determines space-time patterns over Eurasia, has arisen. Intercomparison of the space-time EOF patterns between JRA25 and NCEP (1950-2001) re-analyses show that in autumn, winter and spring the first 3-4 corresponding time coefficients stay at the same order (coefficient correlations between them are significant), while in summer such correspondence in order of modes is changed. (author)

  19. Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.; Kalkhoff, Stephen J.; Hirsch, Robert M.; Liao, Lixia; Barnes, Kimberlee K.

    2014-01-01

    Understanding how nitrogen fluxes respond to changes in agriculture and climate is important for improving water quality. In the midwestern United States, expansion of corn cropping for ethanol production led to increasing N application rates in the 2000s during a period of extreme variability of annual precipitation. To examine the effects of these changes, surface water quality was analyzed in 10 major Iowa Rivers. Several decades of concentration and flow data were analyzed with a statistical method that provides internally consistent estimates of the concentration history and reveals flow-normalized trends that are independent of year-to-year streamflow variations. Flow-normalized concentrations of nitrate+nitrite-N decreased from 2000 to 2012 in all basins. To evaluate effects of annual discharge and N loading on these trends, multiple conceptual models were developed and calibrated to flow-weighted annual concentrations. The recent declining concentration trends can be attributed to both very high and very low discharge in the 2000s and to the long (e.g., 8 year) subsurface residence times in some basins. Dilution of N and depletion of stored N occurs in years with high discharge. Reduced N transport and increased N storage occurs in low-discharge years. Central Iowa basins showed the greatest reduction in flow-normalized concentrations, likely because of smaller storage volumes and shorter residence times. Effects of land-use changes on the water quality of major Iowa Rivers may not be noticeable for years or decades in peripheral basins of Iowa, and may be obscured in the central basins where extreme flows strongly affect annual concentration trends.

  20. Impact of catchment geophysical characteristics and climate on the regional variability of dissolved organic carbon (DOC) in surface water.

    Science.gov (United States)

    Cool, Geneviève; Lebel, Alexandre; Sadiq, Rehan; Rodriguez, Manuel J

    2014-08-15

    Dissolved organic carbon (DOC) is a recognized indicator of natural organic matter (NOM) in surface waters. The aim of this paper is twofold: to evaluate the impact of geophysical characteristics, climate and ecological zones on DOC concentrations in surface waters and, to develop a statistical model to estimate the regional variability of these concentrations. In this study, multilevel statistical analysis was used to achieve three specific objectives: (1) evaluate the influence of climate and geophysical characteristics on DOC concentrations in surface waters; (2) compare the influence of geophysical characteristics and ecological zones on DOC concentrations in surface waters; and (3) develop a model to estimate the most accurate DOC concentrations in surface waters. The case study involved 115 catchments from surface waters in the Province of Quebec, Canada. Results showed that mean temperatures recorded 60 days prior to sampling, total precipitation 10 days prior to sampling and percentages of wetlands, coniferous forests and mixed forests have a significant positive influence on DOC concentrations in surface waters. The catchment mean slope had a significant negative influence on DOC concentrations in surface waters. Water type (lake or river) and deciduous forest variables were not significant. The ecological zones had a significant influence on DOC concentrations. However, geophysical characteristics (wetlands, forests and slope) estimated DOC concentrations more accurately. A model describing the variability of DOC concentrations was developed and can be used, in future research, for estimating DBPs in drinking water as well evaluating the impact of climate change on the quality of surface waters and drinking water. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Laboratory study of SO2 dry deposition on limestone and marble: Effects of humidity and surface variables

    Science.gov (United States)

    Spiker, E. C.; Hosker, R.P.; Weintraub, V.C.; Sherwood, S.I.

    1995-01-01

    The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO2, O3, nitrogen oxides) can be held constant. An airfoil sample holder holds up to eight stone samples (3.8 cm in diameter and 1 cm thick) in nearly identical exposure conditions. SO2 deposition on limestone was found to increase exponentially with increasing relative humidity (RH). Marble behaves similarly, but with a much lower deposition rate. Trends indicate there is little deposition below 20% RH on clean limestone and below 60% RH on clean marble. This large difference is due to the limestone's greater porosity, surface roughness, and effective surface area. These results indicate surface variables generally limit SO2 deposition below about 70% RH on limestone and below at least 95% RH on marble. Aerodynamic variables generally limit deposition at higher relative humidity or when the surface is wet.The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO2, O3

  2. Gaussian-windowed frame based method of moments formulation of surface-integral-equation for extended apertures

    Energy Technology Data Exchange (ETDEWEB)

    Shlivinski, A., E-mail: amirshli@ee.bgu.ac.il [Department of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Lomakin, V., E-mail: vlomakin@eng.ucsd.edu [Department of Electrical and Computer Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0407 (United States)

    2016-03-01

    Scattering or coupling of electromagnetic beam-field at a surface discontinuity separating two homogeneous or inhomogeneous media with different propagation characteristics is formulated using surface integral equation, which are solved by the Method of Moments with the aid of the Gabor-based Gaussian window frame set of basis and testing functions. The application of the Gaussian window frame provides (i) a mathematically exact and robust tool for spatial-spectral phase-space formulation and analysis of the problem; (ii) a system of linear equations in a transmission-line like form relating mode-like wave objects of one medium with mode-like wave objects of the second medium; (iii) furthermore, an appropriate setting of the frame parameters yields mode-like wave objects that blend plane wave properties (as if solving in the spectral domain) with Green's function properties (as if solving in the spatial domain); and (iv) a representation of the scattered field with Gaussian-beam propagators that may be used in many large (in terms of wavelengths) systems.

  3. Estimation of soil hydraulic information through the assimilation of values of the surface moisture: extended approximations (unscented)

    International Nuclear Information System (INIS)

    Medina, Hanoi; Hernández, Yunay; Batista, Giovanni Chirico; Romano, Nunzio

    2008-01-01

    Effective estimation of soil hydraulic information through the assimilation of surface moisture values, demand the use of approximations necessarily related to highly nonlinear models. The Kalman Filter 'Unscented' ( UKF ) has emerged in the literature as a safe and easy technique to implement than the most rudimentary, but more widely used, Kalman Filter 'Linear' (EKF ), for these purposes. However, the efficiency of these techniques depends not only on the approach itself, but also the numerical scheme that supports it. This work is aimed to demonstrate the advantages and disadvantages encountered during implementation of the UKF and EKF in the scheme of numerical solution of the Richards equation to obtain statements and soil parameters by assimilating surface moisture values. Numerical solutions evaluated were implemented using a finite difference scheme. The results demonstrate that a Crack -Nicolson linearized scheme is much more efficient in terms of security and time that based on an explicit scheme and safer than a UKF based on a traditional implicit numerical scheme for estimating profile soil moisture. The latter approach leads to a systematic bias in the solution 'unscented' when the central state is close to saturation. In the dual estimate (state- parameter), certain physical and mathematical parameter constraints, coupled with the bias in the estimates, resulted in substantial difficulties in the practical implementation of this technique using the UKF, or a solution that combines elements of both techniques Kalman filter

  4. Climatic and physiographic controls of spatial variability in surface water balance over the contiguous United States using the Budyko relationship

    Science.gov (United States)

    Abatzoglou, John T.; Ficklin, Darren L.

    2017-09-01

    The geographic variability in the partitioning of precipitation into surface runoff (Q) and evapotranspiration (ET) is fundamental to understanding regional water availability. The Budyko equation suggests this partitioning is strictly a function of aridity, yet observed deviations from this relationship for individual watersheds impede using the framework to model surface water balance in ungauged catchments and under future climate and land use scenarios. A set of climatic, physiographic, and vegetation metrics were used to model the spatial variability in the partitioning of precipitation for 211 watersheds across the contiguous United States (CONUS) within Budyko's framework through the free parameter ω. A generalized additive model found that four widely available variables, precipitation seasonality, the ratio of soil water holding capacity to precipitation, topographic slope, and the fraction of precipitation falling as snow, explained 81.2% of the variability in ω. The ω model applied to the Budyko equation explained 97% of the spatial variability in long-term Q for an independent set of watersheds. The ω model was also applied to estimate the long-term water balance across the CONUS for both contemporary and mid-21st century conditions. The modeled partitioning of observed precipitation to Q and ET compared favorably across the CONUS with estimates from more sophisticated land-surface modeling efforts. For mid-21st century conditions, the model simulated an increase in the fraction of precipitation used by ET across the CONUS with declines in Q for much of the eastern CONUS and mountainous watersheds across the western United States.

  5. Tracing variability in the iodine isotopes and species along surface water transect from the North Sea to the Canary Islands

    DEFF Research Database (Denmark)

    He, Peng; Aldahan, Ala; Hou, Xiaolin

    2016-01-01

    A complete transect of surface water samples from the North Sea to the Canary Islands was collected during a continuous period in 2010. The samples were analyzed for total 129I and 127I isotopes and their iodide and iodate species. The results indicate a large variability in the total 129I and its...

  6. Analysis of the land surface heterogeneity and its impact on atmospheric variables and the aerodynamic and thermodynamic roughness lengths

    NARCIS (Netherlands)

    Ma, Y.M.; Menenti, M.; Feddes, R.A.; Wang, J.M.

    2008-01-01

    The land surface heterogeneity has a very significant impact on atmospheric variables (air temperature T-a, wind speed u, and humidity q), the aerodynamic roughness length z(0m), thermodynamic roughness length z(0h), and the excess resistance to heat transfer kB(-1). First, in this study the land

  7. Variable surface composition and radial interface formation in self-assembled free, mixed Ar/Xe clusters

    International Nuclear Information System (INIS)

    Tchaplyguine, M.; Maartensson, N.; Lundwall, M.; Oehrwall, G.; Feifel, R.; Svensson, S.; Bjoerneholm, O.; Gisselbrecht, M.; Sorensen, S.

    2004-01-01

    Using photoelectron spectroscopy, we demonstrate how the self-assembling process of cluster formation in an adiabatic expansion leads to radial segregation and layering as well as to variable surface composition for binary Ar/Xe clusters. The radial structuring can be qualitatively understood from the different interatomic bonding strengths of the two components

  8. Effects of fin pitch and array of the frost layer growth on extended surface of a heat exchanger

    International Nuclear Information System (INIS)

    Yang, Dong Keun; Lee, Kwan Soo

    2003-01-01

    This paper presents the effects of the fin array and pitch on the frost layer growth of a heat exchanger. The numerical results are compared with experimental data of a cold plate to validate the present model, and agree well with experimental data within a maximum error of 8%. The characteristics of the frost formation on staggered fin array are somewhat different from those of in-line array. For fin pitch below 10 mm, the frost layer growth of second fin in the staggered array is affected by that of first fin. The heat transfer of single fin deteriorate with decreasing fin pitch regardless of fin array, however, the thermal performance of a heat exchanger, considering increase of heat surface area, becomes better

  9. Image-based Exploration of Iso-surfaces for Large Multi- Variable Datasets using Parameter Space.

    KAUST Repository

    Binyahib, Roba S.

    2013-01-01

    -surfaces superimposed on each other. The result is the same as calculating multiple iso- surfaces from the original data but without the memory and processing overhead. Our tool also allows the user to change the (scalar) values superimposed on each of the surfaces

  10. Bacteriophage T4 Nanoparticles as Materials in Sensor Applications: Variables That Influence Their Organization and Assembly on Surfaces

    Directory of Open Access Journals (Sweden)

    Jinny L. Liu

    2009-08-01

    Full Text Available Bacteriophage T4 nanoparticles possess characteristics that make them ideal candidates as materials for sensors, particularly as sensor probes. Their surface can be modified, either through genetic engineering or direct chemical conjugation to display functional moieties such as antibodies or other proteins to recognize a specific target. However, in order for T4 nanoparticles to be utilized as a sensor probe, it is necessary to understand and control the variables that determine their assembly and organization on a surface. The aim of this work is to discuss some of variables that we have identified as influencing the behavior of T4 nanoparticles on surfaces. The effect of pH, ionic strength, substrate characteristics, nanoparticle concentration and charge was addressed qualitatively using atomic force microscopy (AFM.

  11. Low-frequency variability of surface air temperature over the Barents Sea

    NARCIS (Netherlands)

    Linden, van der Eveline C.; Bintanja, Richard; Hazeleger, Wilco; Graversen, R.G.

    2016-01-01

    The predominant decadal to multidecadal variability in the Arctic region is a feature that is not yet well-understood. It is shown that the Barents Sea is a key region for Arctic-wide variability. This is an important topic because low-frequency changes in the ocean might lead to large variations

  12. Extended domains of organized nanorings of silver grains as surface-enhanced Raman scattering sensors for molecular detection

    Energy Technology Data Exchange (ETDEWEB)

    Bechelany, M; Brodard, P; Philippe, L; Michler, J, E-mail: mikhael.bechelany@empa.c, E-mail: pierre.brodard@empa.c [Laboratory for Mechanics of Materials and Nanostructures, EMPA, Swiss Federal Laboratories for Materials Testing and Research, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)

    2009-11-11

    The possibility to synthesize large areas of silver grains organized in nanorings using a simple technique based on nanosphere lithography and electroless plating as a metal deposition method is described for the first time. In addition, we present a systematic SERS study of the obtained long-range ordered silver nanodots and nanorings. The possibility to precisely control the size, the interdistance and the morphology of these nanostructures allows us to systematically investigate the influence of these parameters on SERS. We show that the best possible SERS substrates should not only present optimal sizes, interdistances and shapes, but also a grain-like structure composed of sub-100 nm grains in order to maximize the number of hot-spots. In addition, we show that grains arranged in nanorings present higher enhancement factors (E{sub F} = 5.5 x 10{sup 5}) as compared to similar arrays made of nanodots. A wide range of applications, including real-time monitoring of catalytic surface reactions, environmental and security monitoring as well as clinical and pharmaceutical screening, can be envisaged for these SERS substrates.

  13. Extended domains of organized nanorings of silver grains as surface-enhanced Raman scattering sensors for molecular detection

    Science.gov (United States)

    Bechelany, M.; Brodard, P.; Philippe, L.; Michler, J.

    2009-11-01

    The possibility to synthesize large areas of silver grains organized in nanorings using a simple technique based on nanosphere lithography and electroless plating as a metal deposition method is described for the first time. In addition, we present a systematic SERS study of the obtained long-range ordered silver nanodots and nanorings. The possibility to precisely control the size, the interdistance and the morphology of these nanostructures allows us to systematically investigate the influence of these parameters on SERS. We show that the best possible SERS substrates should not only present optimal sizes, interdistances and shapes, but also a grain-like structure composed of sub-100 nm grains in order to maximize the number of hot-spots. In addition, we show that grains arranged in nanorings present higher enhancement factors (EF = 5.5 × 105) as compared to similar arrays made of nanodots. A wide range of applications, including real-time monitoring of catalytic surface reactions, environmental and security monitoring as well as clinical and pharmaceutical screening, can be envisaged for these SERS substrates.

  14. Extended domains of organized nanorings of silver grains as surface-enhanced Raman scattering sensors for molecular detection

    International Nuclear Information System (INIS)

    Bechelany, M; Brodard, P; Philippe, L; Michler, J

    2009-01-01

    The possibility to synthesize large areas of silver grains organized in nanorings using a simple technique based on nanosphere lithography and electroless plating as a metal deposition method is described for the first time. In addition, we present a systematic SERS study of the obtained long-range ordered silver nanodots and nanorings. The possibility to precisely control the size, the interdistance and the morphology of these nanostructures allows us to systematically investigate the influence of these parameters on SERS. We show that the best possible SERS substrates should not only present optimal sizes, interdistances and shapes, but also a grain-like structure composed of sub-100 nm grains in order to maximize the number of hot-spots. In addition, we show that grains arranged in nanorings present higher enhancement factors (E F = 5.5 x 10 5 ) as compared to similar arrays made of nanodots. A wide range of applications, including real-time monitoring of catalytic surface reactions, environmental and security monitoring as well as clinical and pharmaceutical screening, can be envisaged for these SERS substrates.

  15. Influence of an irregular surface and low light on the step variability of patients with peripheral neuropathy during level gait.

    Science.gov (United States)

    Thies, Sibylle B; Richardson, James K; Demott, Trina; Ashton-Miller, James A

    2005-08-01

    Patients with peripheral neuropathy (PN) report greater difficulty walking on irregular surfaces with low light (IL) than on flat surfaces with regular lighting (FR). We tested the primary hypothesis that older PN patients would demonstrate greater step width and step width variability under IL conditions than under FR conditions. Forty-two subjects (22 male, 20 female: mean +/- S.D.: 64.7 +/- 9.8 years) with PN underwent history, physical examination, and electrodiagnostic testing. Subjects were asked to walk 10 m at a comfortable speed while kinematic and force data were measured at 100 Hz using optoelectronic markers and foot switches. Ten trials were conducted under both IL and FR conditions. Step width, time, length, and speed were calculated with a MATLAB algorithm, with the standard deviation serving as the measure of variability. The results showed that under IL, as compared to FR, conditions subjects demonstrated greater step width (197.1 +/- 40.8 mm versus 180.5 +/- 32.4 mm; P < 0.001) and step width variability (40.4 +/- 9.0 mm versus 34.5 +/- 8.4 mm; P < 0.001), step time and its variability (P < 0.001 and P = 0.003, respectively), and step length variability (P < 0.001). Average step length and gait speed decreased under IL conditions (P < 0.001 for both). Step width variability and step time variability correlated best under IL conditions with a clinical measure of PN severity and fall history, respectively. We conclude that IL conditions cause PN patients to increase the variability of their step width and other gait parameters.

  16. Influence of Surface Roughness Spatial Variability and Temporal Dynamics on the Retrieval of Soil Moisture from SAR Observations

    Directory of Open Access Journals (Sweden)

    Jesús Álvarez-Mozos

    2009-01-01

    Full Text Available Radar-based surface soil moisture retrieval has been subject of intense research during the last decades. However, several difficulties hamper the operational estimation of soil moisture based on currently available spaceborne sensors. The main difficulty experienced so far results from the strong influence of other surface characteristics, mainly roughness, on the backscattering coefficient, which hinders the soil moisture inversion. This is especially true for single configuration observations where the solution to the surface backscattering problem is ill-posed. Over agricultural areas cultivated with winter cereal crops, roughness can be assumed to remain constant along the growing cycle allowing the use of simplified approaches that facilitate the estimation of the moisture content of soils. However, the field scale spatial variability and temporal variations of roughness can introduce errors in the estimation of soil moisture that are difficult to evaluate. The objective of this study is to assess the impact of roughness spatial variability and roughness temporal variations on the retrieval of soil moisture from radar observations. A series of laser profilometer measurements were performed over several fields in an experimental watershed from September 2004 to March 2005. The influence of the observed roughness variability and its temporal variations on the retrieval of soil moisture is studied using simulations performed with the Integral Equation Model, considering different sensor configurations. Results show that both field scale roughness spatial variability and its temporal variations are aspects that need to be taken into account, since they can introduce large errors on the retrieved soil moisture values.

  17. Inter-annual variabilities in biogeophysical feedback of terrestrial ecosystem to atmosphere using a land surface model

    Science.gov (United States)

    Seo, C.; Hong, S.; Jeong, H. M.; Jeon, J.

    2017-12-01

    Biogeophysical processes of terrestrial ecosystem such as water vapor and energy flux are the key features to understand ecological feedback to atmospheric processes and thus role of terrestrial ecosystem in climate system. For example, it has been recently known that the ecological feedback through water vapor and energy flux results in regulating regional weathers and climates which is one of the fundamental functions of terrestrial ecosystem. In regional scale, water vapor flux has been known to give negative feedback to atmospheric warming, while energy flux from the surface has been known to positive feedback. In this study, we explored the inter-annual variabilities in these two biogeophysical features to see how the climate regulating functions of terrestrial ecosystem have been changed with climate change. We selected a land surface model involving vegetation dynamics that is forced by atmospheric data from NASA including precipitation, temperature, wind, surface pressure, humidity, and incoming radiations. From the land surface model, we simulated 60-year water vapor and energy fluxes from 1961 to 2010, and calculates feedbacks of terrestrial ecosystem as in radiation amount into atmosphere. Then, we analyzed the inter-annual variabilities in the feedbacks. The results showed that some mid-latitude areas showing very high variabilities in precipitation showed higher positive feedback and/or lower negative feedback. These results suggest deterioration of the biogeophyisical factor of climate regulating function over those regions.

  18. Low frequency variability of the Indian Ocean from TOPEX/POSEIDON sea surface height anomalies

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, Y.K.; Murty, V.S.N.; Sarma, Y.V.B.

    and off Sumatra present large variability on both seasonal and inter-annual time scales. The SSH anomalies off Sumatra show dominant influence of warm (cold) ENSO events with peak negative (positive) anomalies coinciding with El Nino (La Nina...

  19. The Chameleon Effect: characterization challenges due to the variability of nanoparticles and their surfaces of nanoparticles and their surfaces

    Science.gov (United States)

    Baer, Donald R.

    2018-05-01

    Nanoparticles in a variety of forms are increasing important in fundamental research, technological and medical applications, and environmental or toxicology studies. Physical and chemical drivers that lead to multiple types of particle instabilities complicate both the ability to produce, appropriately characterize, and consistently deliver well-defined particles, frequently leading to inconsistencies and conflicts in the published literature. This perspective suggests that provenance information, beyond that often recorded or reported, and application of a set of core characterization methods, including a surface sensitive technique, consistently applied at critical times can serve as tools in the effort minimize reproducibility issues.

  20. Extended Emotions

    DEFF Research Database (Denmark)

    Krueger, Joel; Szanto, Thomas

    2016-01-01

    beyond the neurophysiological confines of organisms; some even argue that emotions can be socially extended and shared by multiple agents. Call this the extended emotions thesis (ExE). In this article, we consider different ways of understanding ExE in philosophy, psychology, and the cognitive sciences...

  1. Antibodies to variable Plasmodium falciparum-infected erythrocyte surface antigens are associated with protection from novel malaria infections

    DEFF Research Database (Denmark)

    Giha, H A; Staalsoe, T; Dodoo, D

    2000-01-01

    is maintained at low densities. Here, we test the hypothesis that the presence or absence of antibodies against variant antigens on the surface of P. falciparum-infected erythrocytes protect individuals against some infectious challenges and render them susceptible to others. Plasma collected in Daraweesh...... susceptible and protected individuals. Together, the results indicate that pre-existing anti-PfEMP1 antibodies can reduce the risk of contracting clinical malaria when challenged by novel parasite clones expressing homologous, but not heterologous variable surface antigens. The results also confirm...

  2. Superfocusing modes of surface plasmon polaritons in conical geometry based on the quasi-separation of variables approach

    International Nuclear Information System (INIS)

    Kurihara, Kazuyoshi; Otomo, Akira; Syouji, Atsushi; Takahara, Junichi; Suzuki, Koji; Yokoyama, Shiyoshi

    2007-01-01

    Analytic solutions to the superfocusing modes of surface plasmon polaritons in a conical geometry are theoretically studied using an ingenious method called the quasi-separation of variables. This method can be used to look for fundamental solutions to the wave equation for a field that must satisfy boundary conditions at all points on the continuous surface of tapered geometries. The set of differential equations exclusively separated from the wave equation can be consistently solved in combination with perturbation methods. This paper presents the zeroth-order perturbation solution of conical superfocusing modes with azimuthal symmetry and graphically represents them in electric field-line patterns

  3. Connecting the surface to near-shore bottom waters in the California Current ecosystem: a study of Northern California interannual to decadal oceanographic variability

    Science.gov (United States)

    Fish, C.; Hill, T. M.; Davis, C. V.; Lipski, D.; Jahncke, J.

    2017-12-01

    Elucidating both surface and bottom water ecosystem impacts of temperature change, acidification, and food web disruption are needed to understand anthropogenic processes in the ocean. The Applied California Current Ecosystem Studies (ACCESS) partnership surveys the California Current within the Greater Farallones and Cordell Bank National Marine Sanctuaries three times annually, sampling water column hydrography and discrete water samples from 0 m and 200 m depth at five stations along three primary transects. The transects span the continental shelf with stations as close as 13 km from the coastline to 65 km. This time series extends from 2004 to 2017, integrating information on climate, productivity, zooplankton abundance, oxygenation, and carbonate chemistry. We focus on the interpretation of the 2012-2017 carbonate chemistry data and present both long term trends over the duration of the time series as well as shorter term variability (e.g., ENSO, `warm blob' conditions) to investigate the region's changing oceanographic conditions. For example, we document oscillations in carbonate chemistry, oxygenation, and foraminiferal abundance in concert with interannual oceanographic variability and seasonal (upwelling) cycles. We concentrate on results from near Cordell Bank that potentially impact deep sea coral ecosystems.

  4. Annual to Inter-Decadal Variability in Surface Air Temperature Along ...

    African Journals Online (AJOL)

    instrumental sea surface temperature (SST) and. East African rainfall ... accelerated rise in minimum temperatures. The objectives of the ... Altitude above sea level (m) Urban/Exposed. Tanga. 05.05°S ...... Environmental Report, South Florida.

  5. Seasonal variability of sea surface chlorophyll-a of waters around ...

    Indian Academy of Sciences (India)

    days during 1978--1986 are processed to produce sea surface chlorophyll maps ... shallow water areas, in particular waters in Palk Bay and Gulf of Mannar, should be carried out in order .... The circulation penetrates deeper, affecting the.

  6. Surface Complexation Modeling in Variable Charge Soils: Charge Characterization by Potentiometric Titration

    Directory of Open Access Journals (Sweden)

    Giuliano Marchi

    2015-10-01

    Full Text Available ABSTRACT Intrinsic equilibrium constants of 17 representative Brazilian Oxisols were estimated from potentiometric titration measuring the adsorption of H+ and OH− on amphoteric surfaces in suspensions of varying ionic strength. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. The former was fitted by calculating total site concentration from curve fitting estimates and pH-extrapolation of the intrinsic equilibrium constants to the PZNPC (hand calculation, considering one and two reactive sites, and by the FITEQL software. The latter was fitted only by FITEQL, with one reactive site. Soil chemical and physical properties were correlated to the intrinsic equilibrium constants. Both surface complexation models satisfactorily fit our experimental data, but for results at low ionic strength, optimization did not converge in FITEQL. Data were incorporated in Visual MINTEQ and they provide a modeling system that can predict protonation-dissociation reactions in the soil surface under changing environmental conditions.

  7. Bacterial adhesion and biofilm formation on surfaces of variable roughness and hydrophobicity

    DEFF Research Database (Denmark)

    Tang, Lone; Pillai, Saju; Iversen, Anders

    L.Biofilm formation on surfaces in food production and processing can deteriorate the quality of food products and be a hazard to consumers. The food industry currently uses a number of approaches to either remove biofilm or prevent its formation. Due to the inherent resilience of bacteria...... in biofilm, a particularly attractive approach is the modification of surfaces with the aim to impede the first step in biofilm formation, namely bacterial adhesion. Surface properties such as hydrophobicity, roughness and predisposition for fouling by protein are recognised as important in bacterial...... adhesion. Sol-gel technology and the recent availability of organic modified silicas have lead to development of hybrid organic/inorganic glass ceramic coatings with specialised surface properties. In this study we investigate bacterial adhesion and the subsequent biofilm formation on stainless steel (SS...

  8. ClimoBase: Rouse Canadian Surface Observations of Weather, Climate, and Hydrological Variables, 1984-1998

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ClimoBase is a collection of surface climate measurements collected in Northern Canada by Dr. Wayne Rouse between 1984 and 1998 in three locations: Churchill,...

  9. Biological variables for the site survey of surface ecosystems - existing data and survey methods

    International Nuclear Information System (INIS)

    Kylaekorpi, Lasse; Berggren, Jens; Larsson, Mats; Liberg, Maria; Rydgren, Bernt

    2000-06-01

    In the process of selecting a safe and environmentally acceptable location for the deep level repository of nuclear waste, site surveys will be carried out. These site surveys will also include studies of the biota at the site, in order to assure that the chosen site will not conflict with important ecological interests, and to establish a thorough baseline for future impact assessments and monitoring programmes. As a preparation to the site survey programme, a review of the variables that need to be surveyed is conducted. This report contains the review for some of those variables. For each variable, existing data sources and their characteristics are listed. For those variables for which existing data sources are inadequate, suggestions are made for appropriate methods that will enable the establishment of an acceptable baseline. In this report the following variables are reviewed: Fishery, Landscape, Vegetation types, Key biotopes, Species (flora and fauna), Red-listed species (flora and fauna), Biomass (flora and fauna), Water level, water retention time (incl. water body and flow), Nutrients/toxins, Oxygen concentration, Layering, stratification, Light conditions/transparency, Temperature, Sediment transport, (Marine environments are excluded from this review). For a major part of the variables, the existing data coverage is most likely insufficient. Both the temporal and/or the geographical resolution is often limited, which means that complementary surveys must be performed during (or before) the site surveys. It is, however, in general difficult to make exact judgements on the extent of existing data, and also to give suggestions for relevant methods to use in the site surveys. This can be finally decided only when the locations for the sites are decided upon. The relevance of the different variables also depends on the environmental characteristics of the sites. Therefore, we suggest that when the survey sites are selected, an additional review is

  10. Biological variables for the site survey of surface ecosystems - existing data and survey methods

    Energy Technology Data Exchange (ETDEWEB)

    Kylaekorpi, Lasse; Berggren, Jens; Larsson, Mats; Liberg, Maria; Rydgren, Bernt [SwedPower AB, Stockholm (Sweden)

    2000-06-01

    In the process of selecting a safe and environmentally acceptable location for the deep level repository of nuclear waste, site surveys will be carried out. These site surveys will also include studies of the biota at the site, in order to assure that the chosen site will not conflict with important ecological interests, and to establish a thorough baseline for future impact assessments and monitoring programmes. As a preparation to the site survey programme, a review of the variables that need to be surveyed is conducted. This report contains the review for some of those variables. For each variable, existing data sources and their characteristics are listed. For those variables for which existing data sources are inadequate, suggestions are made for appropriate methods that will enable the establishment of an acceptable baseline. In this report the following variables are reviewed: Fishery, Landscape, Vegetation types, Key biotopes, Species (flora and fauna), Red-listed species (flora and fauna), Biomass (flora and fauna), Water level, water retention time (incl. water body and flow), Nutrients/toxins, Oxygen concentration, Layering, stratification, Light conditions/transparency, Temperature, Sediment transport, (Marine environments are excluded from this review). For a major part of the variables, the existing data coverage is most likely insufficient. Both the temporal and/or the geographical resolution is often limited, which means that complementary surveys must be performed during (or before) the site surveys. It is, however, in general difficult to make exact judgements on the extent of existing data, and also to give suggestions for relevant methods to use in the site surveys. This can be finally decided only when the locations for the sites are decided upon. The relevance of the different variables also depends on the environmental characteristics of the sites. Therefore, we suggest that when the survey sites are selected, an additional review is

  11. An LES study on the spatial variability impact of surface sensible heat flux (SHF) on the convective boundary layer (CBL)

    Science.gov (United States)

    Kang, S. L.; Chun, J.; Kumar, A.

    2015-12-01

    We study the spatial variability impact of surface sensible heat flux (SHF) on the convective boundary layer (CBL), using the Weather Research and Forecasting (WRF) model in large eddy simulation (LES) mode. In order to investigate the response of the CBL to multi-scale feature of the surface SHF field over a local area of several tens of kilometers or smaller, an analytic surface SHF map is crated as a function of the chosen feature. The spatial variation in the SHF map is prescribed with a two-dimensional analytical perturbation field, which is generated by using the inverse transform technique of the Fourier series whose coefficients are controlled, of which spectrum to have a particular slope in the chosen range of wavelength. Then, the CBL responses to various SHF heterogeneities are summarized as a function of the spectral slope, in terms of mean structure, turbulence statistics and cross-scale processes. The range of feasible SHF heterogeneities is obtained from the SHF maps produced by a land surface model (LSM) of the WRF system. The LSM-derived SHF maps are a function of geographical data on various resolutions. Based on the numerical experiment results with the surface heterogeneities in the range, we will discuss the uncertainty in the SHF heterogeneity and its impact on the atmosphere in a numerical model. Also we will present the range of spatial scale of the surface SHF heterogeneity that significantly influence on the whole CBL. Lastly, we will report the test result of the hypothesis that the spatial variability of SHF is more representative of surface thermal heterogeneity than is the latent heat flux over the local area of several tens of kilometers or smaller.

  12. Variable Structure Disturbance Rejection Control for Nonlinear Uncertain Systems with State and Control Delays via Optimal Sliding Mode Surface Approach

    Directory of Open Access Journals (Sweden)

    Jing Lei

    2013-01-01

    Full Text Available The paper considers the problem of variable structure control for nonlinear systems with uncertainty and time delays under persistent disturbance by using the optimal sliding mode surface approach. Through functional transformation, the original time-delay system is transformed into a delay-free one. The approximating sequence method is applied to solve the nonlinear optimal sliding mode surface problem which is reduced to a linear two-point boundary value problem of approximating sequences. The optimal sliding mode surface is obtained from the convergent solutions by solving a Riccati equation, a Sylvester equation, and the state and adjoint vector differential equations of approximating sequences. Then, the variable structure disturbance rejection control is presented by adopting an exponential trending law, where the state and control memory terms are designed to compensate the state and control delays, a feedforward control term is designed to reject the disturbance, and an adjoint compensator is designed to compensate the effects generated by the nonlinearity and the uncertainty. Furthermore, an observer is constructed to make the feedforward term physically realizable, and thus the dynamical observer-based dynamical variable structure disturbance rejection control law is produced. Finally, simulations are demonstrated to verify the effectiveness of the presented controller and the simplicity of the proposed approach.

  13. The global surface composition of 67P/Churyumov-Gerasimenko nucleus by Rosetta/VIRTIS. II) Diurnal and seasonal variability

    Science.gov (United States)

    Ciarniello, M.; Raponi, A.; Capaccioni, F.; Filacchione, G.; Tosi, F.; De Sanctis, M. C.; Kappel, D.; Rousseau, B.; Arnold, G.; Capria, M. T.; Barucci, M. A.; Quirico, E.; Longobardo, A.; Kuehrt, E.; Mottola, S.; Erard, S.; Bockelée-Morvan, D.; Leyrat, C.; Migliorini, A.; Zinzi, A.; Palomba, E.; Schmitt, B.; Piccioni, G.; Cerroni, P.; Ip, W.-H.; Rinaldi, G.; Salatti, M.

    2016-11-01

    VIRTIS-M observations of the nucleus of comet 67P/Churyumov-Gerasimenko acquired from 2014 August to 2015 May have been analysed to investigate surface temporal variability at both seasonal and diurnal scales. The measured reflectance spectra are studied by means of comet spectral indicators (CSI) such as slopes in the visible and infrared ranges, and 3.2 μm band area and band centre. CSI maps derived from data acquired at different heliocentric distances (from 3.62 to 1.72 au) along the inbound leg of the comet's orbit are used to infer surface water ice abundance. We measure a global scale enrichment of water ice from 2014 August to 2015 May across the body of the comet, along with variability at small spatial scale, possibly related with the local insolation conditions. Analysis of water ice diurnal variability is performed on 2014 August observations. Water ice appears at the border of receding shadows in the neck of the comet (Hapi), sublimating in less than 1 h, after exposure to sunlight. As similar variability is not observed in other regions of the comet, we interpreted this as the expression of a diurnal cycle of sublimation and re-condensation of water ice, triggered by sudden shadowing produced on the neck by the body and the head of the nucleus.

  14. Temporal and Spatial Variabilities of Japan Sea Surface Temperature and Atmospheric Forcings

    National Research Council Canada - National Science Library

    Chu, Peter C; Chen, Yuchun; Lu, Shihua

    1998-01-01

    ... and their relations to atmospheric forcing. First, we found an asymmetry in the correlation coefficients between SST and wind stress curl, which implies that the SST variability at the scales of the order of one month is largely due to atmospheric forcing...

  15. [Fire behavior of ground surface fuels in Pinus koraiensis and Quercus mongolica mixed forest under no wind and zero slope condition: a prediction with extended Rothermel model].

    Science.gov (United States)

    Zhang, Ji-Li; Liu, Bo-Fei; Chu, Teng-Fei; Di, Xue-Ying; Jin, Sen

    2012-06-01

    A laboratory burning experiment was conducted to measure the fire spread speed, residual time, reaction intensity, fireline intensity, and flame length of the ground surface fuels collected from a Korean pine (Pinus koraiensis) and Mongolian oak (Quercus mongolica) mixed stand in Maoer Mountains of Northeast China under the conditions of no wind, zero slope, and different moisture content, load, and mixture ratio of the fuels. The results measured were compared with those predicted by the extended Rothermel model to test the performance of the model, especially for the effects of two different weighting methods on the fire behavior modeling of the mixed fuels. With the prediction of the model, the mean absolute errors of the fire spread speed and reaction intensity of the fuels were 0.04 m X min(-1) and 77 kW X m(-2), their mean relative errors were 16% and 22%, while the mean absolute errors of residual time, fireline intensity and flame length were 15.5 s, 17.3 kW X m(-1), and 9.7 cm, and their mean relative errors were 55.5%, 48.7%, and 24%, respectively, indicating that the predicted values of residual time, fireline intensity, and flame length were lower than the observed ones. These errors could be regarded as the lower limits for the application of the extended Rothermel model in predicting the fire behavior of similar fuel types, and provide valuable information for using the model to predict the fire behavior under the similar field conditions. As a whole, the two different weighting methods did not show significant difference in predicting the fire behavior of the mixed fuels by extended Rothermel model. When the proportion of Korean pine fuels was lower, the predicted values of spread speed and reaction intensity obtained by surface area weighting method and those of fireline intensity and flame length obtained by load weighting method were higher; when the proportion of Korean pine needles was higher, the contrary results were obtained.

  16. Variability in surface infrared reflectance of thirteen nitrile rubber gloves at key wavelengths for analysis of captan.

    Science.gov (United States)

    Phalen, R N; Que Hee, Shane S

    2007-02-01

    The aim of this study was to investigate the surface variability of 13 powder-free, unlined, and unsupported nitrile rubber gloves using attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectrophotometry at key wavelengths for analysis of captan contamination. The within-glove, within-lot, and between-lot variability was measured at 740, 1124, 1252, and 1735 cm(-1), the characteristic captan reflectance minima wavelengths. Three glove brands were assessed after conditioning overnight at relative humidity (RH) values ranging from 2 +/- 1 to 87 +/- 4% and temperatures ranging from -8.6 +/- 0.7 to 59.2 +/- 0.9 degrees C. For all gloves, 1735 cm(-1) provided the lowest background absorbance and greatest potential sensitivity for captan analysis on the outer glove surface: absorbances ranged from 0.0074 +/- 0.0005 (Microflex) to 0.0195 +/- 0.0024 (SafeSkin); average within-glove coefficients of variation (CV) ranged from 2.7% (Best, range 0.9-5.3%) to 10% (SafeSkin, 1.2-17%); within-glove CVs greater than 10% were for one brand (SafeSkin); within-lot CVs ranged from 2.8% (Best N-Dex) to 28% (SafeSkin Blue); and between-lot variation was statistically significant (p < or = 0.05) for all but two SafeSkin lots. The RH had variable effects dependent on wavelength, being minimal at 1735, 1252, and 1124 cm(-1) and highest at 3430 cm(-1) (O-H stretch region). There was no significant effect of temperature conditioning. Substantial within-glove, within-lot, and between-lot variability was observed. Thus, surface analysis using ATR-FT-IR must treat glove brands and lots as different. ATR-FT-IR proved to be a useful real-time analytical tool for measuring glove variability, detecting surface humidity effects, and choosing selective and sensitive wavelengths for analysis of nonvolatile surface contaminants.

  17. Sea surface temperature and sea ice variability in the subpolar North Atlantic from explosive volcanism of the late thirteenth century

    DEFF Research Database (Denmark)

    Sicre, M. -A.; Khodri, M.; Mignot, J.

    2013-01-01

    In this study, we use IP25 and alkenone biomarker proxies to document the subdecadal variations of sea ice and sea surface temperature in the subpolar North Atlantic induced by the decadally paced explosive tropical volcanic eruptions of the second half of the thirteenth century. The short-and long......-term evolutions of both variables were investigated by cross analysis with a simulation of the IPSL-CM5A LR model. Our results show short-term ocean cooling and sea ice expansion in response to each volcanic eruption. They also highlight that the long response time of the ocean leads to cumulative surface cooling...... and subsurface heat buildup due to sea ice capping. As volcanic forcing relaxes, the surface ocean rapidly warms, likely amplified by subsurface heat, and remains almost ice free for several decades....

  18. The relative contributions of tropical Pacific sea surface temperatures and atmospheric internal variability to the recent global warming hiatus

    Science.gov (United States)

    Deser, Clara; Guo, Ruixia; Lehner, Flavio

    2017-08-01

    The recent slowdown in global mean surface temperature (GMST) warming during boreal winter is examined from a regional perspective using 10-member initial-condition ensembles with two global coupled climate models in which observed tropical Pacific sea surface temperature anomalies (TPAC SSTAs) and radiative forcings are specified. Both models show considerable diversity in their surface air temperature (SAT) trend patterns across the members, attesting to the importance of internal variability beyond the tropical Pacific that is superimposed upon the response to TPAC SSTA and radiative forcing. Only one model shows a close relationship between the realism of its simulated GMST trends and SAT trend patterns. In this model, Eurasian cooling plays a dominant role in determining the GMST trend amplitude, just as in nature. In the most realistic member, intrinsic atmospheric dynamics and teleconnections forced by TPAC SSTA cause cooling over Eurasia (and North America), and contribute equally to its GMST trend.

  19. Estimating space-time mean concentrations of nutrients in surface waters of variable depth

    NARCIS (Netherlands)

    Knotters, M.; Brus, D.J.

    2010-01-01

    A monitoring scheme has been designed to test whether the space-time mean concentration total Nitrogen (N-total) in the surface water in the Northern Frisian Woodlands (NFW, The Netherlands) complies with standards of the European Water Framework directive. Since in statistical testing for

  20. The variability of surface water quality indicators in relation to watercourse typology, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Langhammer, J.; Hartvich, Filip; Mattas, D.; Rödlová, S.; Zbořil, A.

    2012-01-01

    Roč. 184, č. 6 (2012), s. 3983-3999 ISSN 0167-6369 Institutional research plan: CEZ:AV0Z30460519 Keywords : water framework directive * typology * Surface water quality Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.592, year: 2012

  1. A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for In-Situ Mars Surface Sample Analysis

    Science.gov (United States)

    Edmunson, J.; Gaskin, J. A.; Jerman, G. A.; Harvey, R. P.; Doloboff, I. J.; Neidholdt, E. L.

    2016-01-01

    The Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Sciences (ROSES), will build upon previous miniaturized SEM designs and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. This project is a collaboration between NASA Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), electron gun and optics manufacturer Applied Physics Technologies, and small vacuum system manufacturer Creare. Dr. Ralph Harvery and environmental SEM (ESEM) inventor Dr. Gerry Danilatos serve as advisors to the team. Variable pressure SEMs allow for fine (nm-scale) resolution imaging and micron-scale chemical study of materials without sample preparation (e.g., carbon or gold coating). Charging of a sample is reduced or eliminated by the gas surrounding the sample. It is this property of ESEMs that make them ideal for locations where sample preparation is not yet feasible, such as the surface of Mars. In addition, the lack of sample preparation needed here will simplify the sample acquisition process and allow caching of the samples for future complementary payload use.

  2. Surface Complexation Modeling in Variable Charge Soils: Prediction of Cadmium Adsorption

    Directory of Open Access Journals (Sweden)

    Giuliano Marchi

    2015-10-01

    Full Text Available ABSTRACT Intrinsic equilibrium constants for 22 representative Brazilian Oxisols were estimated from a cadmium adsorption experiment. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. Intrinsic equilibrium constants were optimized by FITEQL and by hand calculation using Visual MINTEQ in sweep mode, and Excel spreadsheets. Data from both models were incorporated into Visual MINTEQ. Constants estimated by FITEQL and incorporated in Visual MINTEQ software failed to predict observed data accurately. However, FITEQL raw output data rendered good results when predicted values were directly compared with observed values, instead of incorporating the estimated constants into Visual MINTEQ. Intrinsic equilibrium constants optimized by hand calculation and incorporated in Visual MINTEQ reliably predicted Cd adsorption reactions on soil surfaces under changing environmental conditions.

  3. Controlling Nanocrystal Superlattice Symmetry and Shape-Anisotropic Interactions through Variable Ligand Surface Coverage

    KAUST Repository

    Choi, Joshua J.; Bealing, Clive R.; Bian, Kaifu; Hughes, Kevin J.; Zhang, Wenyu; Smilgies, Detlef-M.; Hennig, Richard G.; Engstrom, James R.; Hanrath, Tobias

    2011-01-01

    The assembly of colloidal nanocrystals (NCs) into superstructures with long-range translational and orientational order is sensitive to the molecular interactions between ligands bound to the NC surface. We illustrate how ligand coverage on colloidal PbS NCs can be exploited as a tunable parameter to direct the self-assembly of superlattices with predefined symmetry. We show that PbS NCs with dense ligand coverage assemble into face-centered cubic (fcc) superlattices whereas NCs with sparse ligand coverage assemble into body-centered cubic (bcc) superlattices which also exhibit orientational ordering of NCs in their lattice sites. Surface chemistry characterization combined with density functional theory calculations suggest that the loss of ligands occurs preferentially on {100} than on reconstructed {111} NC facets. The resulting anisotropic ligand distribution amplifies the role of NC shape in the assembly and leads to the formation of superlattices with translational and orientational order. © 2011 American Chemical Society.

  4. Controlling Nanocrystal Superlattice Symmetry and Shape-Anisotropic Interactions through Variable Ligand Surface Coverage

    KAUST Repository

    Choi, Joshua J.

    2011-03-09

    The assembly of colloidal nanocrystals (NCs) into superstructures with long-range translational and orientational order is sensitive to the molecular interactions between ligands bound to the NC surface. We illustrate how ligand coverage on colloidal PbS NCs can be exploited as a tunable parameter to direct the self-assembly of superlattices with predefined symmetry. We show that PbS NCs with dense ligand coverage assemble into face-centered cubic (fcc) superlattices whereas NCs with sparse ligand coverage assemble into body-centered cubic (bcc) superlattices which also exhibit orientational ordering of NCs in their lattice sites. Surface chemistry characterization combined with density functional theory calculations suggest that the loss of ligands occurs preferentially on {100} than on reconstructed {111} NC facets. The resulting anisotropic ligand distribution amplifies the role of NC shape in the assembly and leads to the formation of superlattices with translational and orientational order. © 2011 American Chemical Society.

  5. Low footwall accelerations and variable surface rupture behavior on the Fort Sage Mountains fault, northeast California

    Science.gov (United States)

    Briggs, Richard W.; Wesnousky, Steven G.; Brune, James N.; Purvance, Matthew D.; Mahan, Shannon

    2013-01-01

    The Fort Sage Mountains fault zone is a normal fault in the Walker Lane of the western Basin and Range that produced a small surface rupture (L 5.6 earthquake in 1950. We investigate the paleoseismic history of the Fort Sage fault and find evidence for two paleoearthquakes with surface displacements much larger than those observed in 1950. Rupture of the Fort Sage fault ∼5.6  ka resulted in surface displacements of at least 0.8–1.5 m, implying earthquake moment magnitudes (Mw) of 6.7–7.1. An older rupture at ∼20.5  ka displaced the ground at least 1.5 m, implying an earthquake of Mw 6.8–7.1. A field of precariously balanced rocks (PBRs) is located less than 1 km from the surface‐rupture trace of this Holocene‐active normal fault. Ground‐motion prediction equations (GMPEs) predict peak ground accelerations (PGAs) of 0.2–0.3g for the 1950 rupture and 0.3–0.5g for the ∼5.6  ka paleoearthquake one kilometer from the fault‐surface trace, yet field tests indicate that the Fort Sage PBRs will be toppled by PGAs between 0.1–0.3g. We discuss the paleoseismic history of the Fort Sage fault in the context of the nearby PBRs, GMPEs, and probabilistic seismic hazard maps for extensional regimes. If the Fort Sage PBRs are older than the mid‐Holocene rupture on the Fort Sage fault zone, this implies that current GMPEs may overestimate near‐fault footwall ground motions at this site.

  6. Variability of solar radiation and CDOM in surface coastal waters of the northwestern Mediterranean sea

    OpenAIRE

    Sempéré, Richard; Para, J.; Tedetti, Marc; Charriere, B.; Mallet, M.

    2015-01-01

    Atmospheric and in-water solar radiation, including UVR-B, UVR-A and PAR, as well as chromophoric dissolved organic matter absorption [a(CDOM)()] in surface waters were monthly measured from November 2007 to December 2008 at a coastal station in the Northwestern Mediterranean Sea (Bay of Marseilles, France). Our results showed that the UVR-B/UVR-A ratio followed the same trend in the atmosphere and at 2m depth in the water (P

  7. A Simple and Improved HPLC-PDA Method for Simultaneous Estimation of Fexofenadine and Pseudoephedrine in Extended Release Tablets by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Ruhul Kayesh

    2017-01-01

    Full Text Available A simple RP-HPLC method has been developed for simultaneous estimation of fexofenadine and pseudoephedrine in their extended release tablet. The method was developed based on statistical design of experiments (DoE and Response Surface Methodology. Separation was achieved on double end-capped C18 column (250 mm × 4 mm, 5 μm. In this experiment, two components of mobile phase, namely, acetonitrile (% v/v and methanol (% v/v, were the factors whereas retention and resolution of the chromatographic peaks were the responses. The effects of different composition of factors on the corresponding responses were investigated. The optimum chromatographic condition for the current case was found as an isocratic mobile phase consisting of 20 mM phosphate buffer (pH 6.8 and acetonitrile and methanol in a ratio of 50 : 36 : 14 (% v/v at a flow rate of 1 mL/min for 7 minutes. The retention of pseudoephedrine and fexofenadine was found to be 2.6 min and 4.7 min, respectively. The method was validated according to the ICH and FDA guidelines and various validation parameters were determined. Also, forced degradation studies in acid, base, oxidation, and reduction media and in thermal condition were performed to establish specificity and stability-indicating property of this method. Practical applicability of this method was checked in extended release tablets available in Bangladeshi market.

  8. Eelgrass Leaf Surface Microbiomes Are Locally Variable and Highly Correlated with Epibiotic Eukaryotes

    Directory of Open Access Journals (Sweden)

    Mia M. Bengtsson

    2017-07-01

    Full Text Available Eelgrass (Zostera marina is a marine foundation species essential for coastal ecosystem services around the northern hemisphere. Like all macroscopic organisms, it possesses a microbiome (here defined as an associated prokaryotic community which may play critical roles in modulating the interaction of eelgrass with its environment. For example, its leaf surface microbiome could inhibit or attract eukaryotic epibionts which may overgrow the eelgrass leading to reduced primary productivity and subsequent eelgrass meadow decline. We used amplicon sequencing of the 16S and 18S rRNA genes of prokaryotes and eukaryotes to assess the leaf surface microbiome (prokaryotes as well as eukaryotic epibionts in- and outside lagoons on the German Baltic Sea coast. Prokaryote microbiomes varied substantially both between sites inside lagoons and between open coastal and lagoon sites. Water depth, leaf area and biofilm chlorophyll a concentration explained a large amount of variation in both prokaryotic and eukaryotic community composition. The prokaryotic microbiome and eukaryotic epibiont communities were highly correlated, and network analysis revealed disproportionate co-occurrence between a limited number of eukaryotic taxa and several bacterial taxa. This suggests that eelgrass leaf surfaces are home to a mosaic of microbiomes of several epibiotic eukaryotes, in addition to the microbiome of the eelgrass itself. Our findings thereby underline that eukaryotic diversity should be taken into account in order to explain prokaryotic microbiome assembly and dynamics in aquatic environments.

  9. Sample mounting and transfer for coupling an ultrahigh vacuum variable temperature beetle scanning tunneling microscope with conventional surface probes

    International Nuclear Information System (INIS)

    Nafisi, Kourosh; Ranau, Werner; Hemminger, John C.

    2001-01-01

    We present a new ultrahigh vacuum (UHV) chamber for surface analysis and microscopy at controlled, variable temperatures. The new instrument allows surface analysis with Auger electron spectroscopy, low energy electron diffraction, quadrupole mass spectrometer, argon ion sputtering gun, and a variable temperature scanning tunneling microscope (VT-STM). In this system, we introduce a novel procedure for transferring a sample off a conventional UHV manipulator and onto a scanning tunneling microscope in the conventional ''beetle'' geometry, without disconnecting the heating or thermocouple wires. The microscope, a modified version of the Besocke beetle microscope, is mounted on a 2.75 in. outer diameter UHV flange and is directly attached to the base of the chamber. The sample is attached to a tripod sample holder that is held by the main manipulator. Under UHV conditions the tripod sample holder can be removed from the main manipulator and placed onto the STM. The VT-STM has the capability of acquiring images between the temperature range of 180--500 K. The performance of the chamber is demonstrated here by producing an ordered array of island vacancy defects on a Pt(111) surface and obtaining STM images of these defects

  10. Extended thermodynamics

    CERN Document Server

    Müller, Ingo

    1993-01-01

    Physicists firmly believe that the differential equations of nature should be hyperbolic so as to exclude action at a distance; yet the equations of irreversible thermodynamics - those of Navier-Stokes and Fourier - are parabolic. This incompatibility between the expectation of physicists and the classical laws of thermodynamics has prompted the formulation of extended thermodynamics. After describing the motifs and early evolution of this new branch of irreversible thermodynamics, the authors apply the theory to mon-atomic gases, mixtures of gases, relativistic gases, and "gases" of phonons and photons. The discussion brings into perspective the various phenomena called second sound, such as heat propagation, propagation of shear stress and concentration, and the second sound in liquid helium. The formal mathematical structure of extended thermodynamics is exposed and the theory is shown to be fully compatible with the kinetic theory of gases. The study closes with the testing of extended thermodynamics thro...

  11. Seasonal and inter-annual variability of sea surface temperature at the east coast fishing area off Peninsular Malaysia

    Science.gov (United States)

    Nurul Ridani, S.; Mustapha, M. A.; Lihan, T.; Ku Kassim, K. Y.; Raja Bidin, R. H.

    2015-09-01

    Empirical orthogonal function (EOF) analysis was used to study a time-series of the aqua MODIS data imageries in the exclusive economic zone of east coast off Peninsular Malaysia. Temporal and spatial characteristics were examined to determine the dominant pattern of sea surface temperature (SST) variability from January 2003 to December 2011.The data were analysed from daily Level 1A (1km spatial resolution) to monthly composites Level 3 data using SeaDAS and ERDAS imagine software. Four modes was obtained from the analysis with the highest variance (7.9%) represented by mode 1 which explained the seasonal cycle. Mode 2 (5.11 % of total variance) showed positive and negative peak signal during March and April and in October and November with variability near the Kelantan and Pahang waters that indicated the inter monsoon. Mode 3 (3.8 % of variance) shows variability near the Terengganu, Kelantan and Johor waters to the open sea during July and August and in May and June representing the Southwest monsoon. Mode 4 (3.36 %) showed positive signal during November and December with strong signal near Pahang and Kelantan waters while weak signal was detected near Terengganu and Kelantan's open sea representing the Northeast monsoon. The SST variability was influenced by the monsoonal system which originated by the wind forcing condition that influences circulation in the study area.

  12. Brief Communication: Upper Air Relaxation in RACMO2 Significantly Improves Modelled Interannual Surface Mass Balance Variability in Antarctica

    Science.gov (United States)

    van de Berg, W. J.; Medley, B.

    2016-01-01

    The Regional Atmospheric Climate Model (RACMO2) has been a powerful tool for improving surface mass balance (SMB) estimates from GCMs or reanalyses. However, new yearly SMB observations for West Antarctica show that the modelled interannual variability in SMB is poorly simulated by RACMO2, in contrast to ERA-Interim, which resolves this variability well. In an attempt to remedy RACMO2 performance, we included additional upper-air relaxation (UAR) in RACMO2. With UAR, the correlation to observations is similar for RACMO2 and ERA-Interim. The spatial SMB patterns and ice-sheet-integrated SMB modelled using UAR remain very similar to the estimates of RACMO2 without UAR. We only observe an upstream smoothing of precipitation in regions with very steep topography like the Antarctic Peninsula. We conclude that UAR is a useful improvement for regional climate model simulations, although results in regions with steep topography should be treated with care.

  13. Interactions of Mineral Dust with Clouds, Sea Surface Temperature, and Climate Modes of Variability

    Science.gov (United States)

    DeFlorio, Michael J.

    Global climate models (GCMs) are a vital tool for ensuring the prosperity and security of modern society. They allow scientists to understand complex interactions between the air, ocean, and land, and are used by policymakers to project future changes in climate on regional and global scales. The previous generation of GCMs, represented by CMIP3 models, are shown to be deficient in their representation of precipitation over the western United States, a region that depends critically on wintertime orographically enhanced precipitation for drinking water. In addition, aerosol-cloud interactions were prescribed in CMIP3 models, which decreased the value of their representation of global aerosol, cloud, and precipitation features. This has potentially large impacts on global radiation budgets, since aerosol-cloud interactions affect the spatial extent and magnitude of clouds and precipitation. The newest suite of GCMs, the Coupled Model Intercomparison Project Phase 5 (CMIP5) models, includes state-of-the-art parameterizations of small-scale features such as aerosols, clouds, and precipitation, and is widely used by the scientific community to learn more about the climate system. The Community Earth System Model (CESM), in conjunction with observations, provides several simulations to investigate the role of aerosols, clouds, and precipitation in the climate system and how they interact with larger modes of climate variability. We show that CESM produces a realistic spatial distribution of precipitation extremes over the western U.S., and that teleconnected signals of ENSO and the Pacific Decadal Oscillation to large-scale circulation patterns and precipitation over the western U.S. are improved when compared to CCSM3. We also discover a new semi-direct effect between dust and stratocumulus clouds over the subtropical North Atlantic, whereby boundary layer inversion strength increases during the most dusty summers due to shortwave absorption of dust above the planetary

  14. The impact of land use change and hydroclimatic variability on landscape connectivity dynamics across surface water networks at subcontinental scale

    Science.gov (United States)

    Tulbure, M. G.; Bishop-Taylor, R.; Broich, M.

    2017-12-01

    Land use (LU) change and hydroclimatic variability affect spatiotemporal landscape connectivity dynamics, important for species movement and dispersal. Despite the fact that LU change can strongly influence dispersal potential over time, prior research has only focused on the impacts of dynamic changes in the distribution of potential habitats. We used 8 time-steps of historical LU together with a Landsat-derived time-series of surface water habitat dynamics (1986-2011) over the Murray-Darling Basin (MDB), a region with extreme hydroclimatic variability, impacted by LU changes. To assess how changing LU and hydroclimatic variability affect landscape connectivity across time, we compared 4 scenarios, namely one where both climate and LU are dynamic over time, one where climate is kept steady (i.e. a median surface water extent layer), and two scenarios where LU is kept steady (i.e. resistance values associated with the most recent or the first LU layer). We used circuit theory to assign landscape features with `resistance' costs and graph theory network analysis, with surface water habitats as `nodes' connected by dispersal paths or `edges' Findings comparing a dry and an average season show high differences in number of nodes (14581 vs 21544) and resistance distances. The combined effect of LU change and landscape wetness was lower than expected, likely a function of the large, MDB-wide, aggregation scale. Spatially explicit analyses are expected to identify areas where the synergistic effect of LU change and landscape wetness greatly reduce or increase landscape connectivity, as well as areas where the two effects cancel each other out.

  15. The Chameleon Effect: Characterization Challenges Due to the Variability of Nanoparticles and Their Surfaces

    Directory of Open Access Journals (Sweden)

    Donald R. Baer

    2018-05-01

    Full Text Available Nanoparticles in a variety of forms are increasing important in fundamental research, technological and medical applications, and environmental or toxicology studies. Physical and chemical drivers that lead to multiple types of particle instabilities complicate both the ability to produce, appropriately characterize, and consistently deliver well-defined particles, frequently leading to inconsistencies, and conflicts in the published literature. This perspective suggests that provenance information, beyond that often recorded or reported, and application of a set of core characterization methods, including a surface sensitive technique, consistently applied at critical times can serve as tools in the effort minimize reproducibility issues.

  16. The Chameleon Effect: characterization challenges due to the variability of nanoparticles and their surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Donald R.

    2018-05-07

    Nanoparticles in a variety of forms are of increasing importance in fundamental research, technological and medical applications, and environmental or toxicology studies. Physical and chemical drivers that lead to multiple types of particle instabilities complicate both the ability to produce and consistently deliver well defined particles and their appropriate characterization, frequently leading to inconsistencies and conflicts in the published literature. This perspective suggests that provenance information, beyond that often recorded or reported, and application of a set of core characterization methods, including a surface sensitive technique, consistently applied at critical times can serve as tools in the effort minimize reproducibility issues.

  17. DNA secondary structures are associated with recombination in major Plasmodium falciparum variable surface antigen gene families

    DEFF Research Database (Denmark)

    Sander, Adam F.; Lavstsen, Thomas; Rask, Thomas Salhøj

    2014-01-01

    falciparum-erythrocyte membrane protein 1 class on the infected erythrocyte surface. Recombination clearly generates var diversity, but the nature and control of the genetic exchanges involved remain unclear. By experimental and bioinformatic identification of recombination events and genome...... of recombination during DNA replication in P. falciparum sexual stages, and that these DSS-regulated genetic exchanges generate functional and diverse P. falciparum adhesion antigens. DSS-induced recombination may represent a common mechanism for optimizing the evolvability of virulence gene families in pathogens....

  18. Annual and latitudinal variations of surface fluxes and meteorological variables at Arctic terrestrial sites

    Science.gov (United States)

    Grachev, Andrey; Uttal, Taneil; Persson, Ola; Konopleva-Akish, Elena; Crepinsek, Sara; Cox, Christopher; Fairall, Christopher; Makshtas, Alexander; Repina, Irina

    2016-04-01

    This study analyzes and discusses seasonal and latitudinal variations of surface fluxes (turbulent, radiative, and soil ground heat) and other ancillary surface/snow/permafrost data based on in-situ measurements made at two long-term research observatories near the coast of the Arctic Ocean located in Canada and Russia. The hourly averaged data collected at Eureka (Canadian territory of Nunavut) and Tiksi (East Siberia) located at two quite different latitudes (80.0 N and 71.6 N respectively) are analyzed in details to describe the seasons in the Arctic. Although Eureka and Tiksi are located at the different continents and at the different latitudes, the annual course of the surface meteorology and the surface fluxes are qualitatively very similar. The air and soil temperatures display the familiar strong seasonal trend with maximum of measured temperatures in mid-summer and minimum during winter. According to our data, variation in incoming short-wave solar radiation led the seasonal pattern of the air and soil temperatures, and the turbulent fluxes. During the dark Polar nights, air and ground temperatures are strongly controlled by long-wave radiation associated generally with cloud cover. Due to the fact that in average the higher latitudes receive less solar radiation than lower latitudes, a length of the convective atmospheric boundary layer (warm season) is shorter and middle-summer amplitude of the turbulent fluxes is generally less in Eureka than in Tiksi. However, since solar elevation angle at local midnight in the middle of Arctic summer is higher for Eureka as compared to Tiksi, stable stratification and upward turbulent flux for carbon dioxide is generally did not observed at Eureka site during summer seasons. It was found a high correlation between the turbulent fluxes of sensible and latent heat, carbon dioxide and the net solar radiation. A comprehensive evaluation of energy balance closure problem is performed based on the multi-year data sets

  19. Variable Camber Continuous Aerodynamic Control Surfaces and Methods for Active Wing Shaping Control

    Science.gov (United States)

    Nguyen, Nhan T. (Inventor)

    2016-01-01

    An aerodynamic control apparatus for an air vehicle improves various aerodynamic performance metrics by employing multiple spanwise flap segments that jointly form a continuous or a piecewise continuous trailing edge to minimize drag induced by lift or vortices. At least one of the multiple spanwise flap segments includes a variable camber flap subsystem having multiple chordwise flap segments that may be independently actuated. Some embodiments also employ a continuous leading edge slat system that includes multiple spanwise slat segments, each of which has one or more chordwise slat segment. A method and an apparatus for implementing active control of a wing shape are also described and include the determination of desired lift distribution to determine the improved aerodynamic deflection of the wings. Flap deflections are determined and control signals are generated to actively control the wing shape to approximate the desired deflection.

  20. Melting heat transfer in stagnation point flow of carbon nanotubes towards variable thickness surface

    Directory of Open Access Journals (Sweden)

    T. Hayat

    2016-01-01

    Full Text Available This work concentrates on the mathematical modeling for stagnation point flow of nanofluids over an impermeable stretching sheet with variable thickness. Carbon nanotubes [single-wall carbon nanotubes (SWCNTs and multi-wall carbon nanotubes (MWCNTs] as the nanoparticles are utilized. Water and kerosene oil are taken as the base fluids. Heat transfer through melting effect is discussed. Transformation procedure is adapted to obtain the non-linear ordinary differential equations from the fundamental laws of mass, linear momentum and energy. The optimal values of convergence control parameters and corresponding individual and total residual errors for SWCNTs and MWCNTs are computed by means of homotopy analysis method (HAM based BVPh 2.0. Characteristics of different involved parameters on the velocity, temperature, skin friction coefficient and Nusselt number are discussed. Higher velocity profile is observed for wall thickness parameter in case of water carbon nanotubes when compared with the kerosene oil carbon nanotubes.

  1. Sea surface temperature variability at the Scripps Institution of Oceanography Pier

    DEFF Research Database (Denmark)

    Checkley, David M.; Lindegren, Martin

    2014-01-01

    similar results. SSTSIO measured over three days shows a diel cycle and short-term variability consistent with rip current transport of warm surf zone water to the end of the SIO pier. We hypothesize that rip current transport increased with the change from the old to the present pier and contributed...... to the observed discontinuity in SIO pier SST. We estimate an artifact of ~ +0.45°C due to both rapid (1988 pier change) and gradual processes. Adjusting the SIO pier SST time series for this artifact reduces the long-term trend from +1.1°C/century to +0.6°C/century, consistent with the global rate of change...

  2. Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Jesbin, G.

    –885, 2016 www.ann-geophys.net/34/871/2016/ doi:10.5194/angeo-34-871-2016 © Author(s) 2016. CC Attribution 3.0 License. Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea V. Sanil Kumar and Jesbin... of the period. The annual average value is ∼ 1.5 m (Anoop et al., 2015). During the non-monsoon period, the land and sea breeze has a signif- icant influence on the wave climate of eastern AS (Glejin Ann. Geophys., 34, 871–885, 2016 www.ann-geophys.net/34...

  3. Stability of Marangoni Convection in a Fluid Layer with Variable Viscosity and deformable Free Surface under Free-Slip condition

    Directory of Open Access Journals (Sweden)

    Nurul Hafizah Zainal Abidin

    2009-01-01

    Full Text Available The steady marangoni convection is investigated in ahorizontal layer of fluid with a free-slip bottom heated frombelow and cooled from above. Since the viscosity is temperaturedependentthe consequences of relaxing oberbeck-boussinesqapproximation and free surface deformability are theoreticallyexamined by means of small disturbance analysis. Prediction forthe onset of convection are obtained from the analysis bynumerical technique. The effect of variable viscosity and surfacedeformation on the onset of fluid motion is investigated in detail.It is shown that the critical values of marangoni and wavenumber depend strongly on the viscosity variation and surfacedeformation.

  4. Tracing variability in the iodine isotopes and species along surface water transect from the North Sea to the Canary Islands

    International Nuclear Information System (INIS)

    Peng He; Ala Aldahan; Uppsala University, Uppsala; Xiaolin Hou; Chinese Academy of Sciences, Xi'an; Possnert, Goran

    2016-01-01

    A complete transect of surface water samples from the North Sea to the Canary Islands was collected during a continuous period in 2010. The samples were analyzed for total 129 I and 127 I isotopes and their iodide and iodate species. The results indicate a large variability in the total 129 I and its species along the transect, whereas less change and variation are observed for the total 127 I and its species. Transport of 129 I from the western English Channel via Biscay Bay is the main source of 129 I in the northeastern Atlantic Ocean. (author)

  5. Variable but persistent coexistence of Prochlorococcus ecotypes along temperature gradients in the ocean's surface mixed layer.

    Science.gov (United States)

    Chandler, Jeremy W; Lin, Yajuan; Gainer, P Jackson; Post, Anton F; Johnson, Zackary I; Zinser, Erik R

    2016-04-01

    The vast majority of the phytoplankton communities in surface mixed layer of the oligotrophic ocean are numerically dominated by one of two ecotypes of Prochlorococcus, eMIT9312 or eMED4. In this study, we surveyed large latitudinal transects in the Atlantic and Pacific Ocean to determine if these ecotypes discretely partition the surface mixed layer niche, or if populations exist as a continuum along key environmental gradients, particularly temperature. Transitions of dominance occurred at approximately 19-21°C, with the eMED4 ecotype dominating the colder, and eMIT9312 ecotype dominating the warmer regions. Within these zones of regional dominance, however, the minority ecotype was not competed to extinction. Rather, a robust log-linear relationship between ecotype ratio and temperature characterized this stabilized coexistence: for every 2.5°C increase in temperature, the eMIT9312:eMED4 ratio increased by an order of magnitude. This relationship was observed in both quantitative polymerase chain reaction and in pyrosequencing assays. Water column stratification also contributed to the ecotype ratio along the basin-scale transects, but to a lesser extent. Finally, instances where the ratio of the eMED4 and eMIT9312 abundances did not correlate well with temperature were identified. Such occurrences are likely due to changes in water temperatures outpacing changes in community structure. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Seasonal and Interannual Variability of Eddy Field and Surface Circulation in the Gulf of Aden

    Science.gov (United States)

    Al Saafani, M. A.; Shenoi, S. S. C.

    2006-07-01

    The circulation in the Gulf of Aden is inferred from three different data sets: h istorical sh ip drifts , hydrography , and satellite altimeter derived sea level (Topex/Poseidon, Jason and ERS) . The circulation in th is semi-enclosed basin is marked with strong seasonality with reversals in the direction of flows twice a year follow ing the reversal in mon soonal winds. During the win ter mon soon (November - February) there is an inflow from Arabian Sea; an extension of Arabian Coastal Current (ACC) . During sou thwest mon soon (June - August) the flow is generally towards east especially along the northern coast of Gulf of Aden. The geostrophic currents also show that the circulation in the gulf is embedded with mesoscale eddies. These westward propagating eddies appear to enter the Gulf of Aden from the western Arabian Sea in win ter. The relative contribu tion of mesoscale eddies to the circulation in the gulf were estimated using altimeter derived Sea level anomaly (SLA) for the years 1993 to 2003 . The effect of these mesoscale eddies extend over the entire water colu mn . The propagation speeds, of these eddies, estimated using weekly spaced altimeter derived SLA (2002 - 2003) is ~ 4 .0 - 5 .3 cm s . The sum of the speeds of second mode Ro ssby wave and the mean current (4.8 cm s ) matches with the propagation speeds of eddies estimated using SLA . Hence, second mode baroclin ic Rossby waves appear to be responsib le for the westward propagation of eddies in the Gulf of Aden. The presence of these eddies in the temperaturesalin ity climato logy confirms that they are no t transient features.

  7. Macrophyte decomposition in a surface-flow ammonia-dominated constructed wetland: Rates associated with environmental and biotic variables

    Science.gov (United States)

    Thullen, J.S.; Nelson, S.M.; Cade, B.S.; Sartoris, J.J.

    2008-01-01

    Decomposition of senesced culm material of two bulrush species was studied in a surface-flow ammonia-dominated treatment wetland in southern California. Decomposition of the submerged culm material during summer months was relatively rapid (k = 0.037 day-1), but slowed under extended submergence (up to 245 days) and during fall and spring sampling periods (k = 0.009-0.014 day-1). Stepwise regression of seasonal data indicated that final water temperature and abundance of the culm-mining midge, Glyptotendipes, were significantly associated with culm decomposition. Glyptotendipes abundance, in turn, was correlated with water quality parameters such as conductivity and dissolved oxygen and ammonia concentrations. No differences were detected in decomposition rates between the bulrush species, Schoenoplectus californicus and Schoenoplectus acutus.

  8. Rational extended thermodynamics

    CERN Document Server

    Müller, Ingo

    1998-01-01

    Ordinary thermodynamics provides reliable results when the thermodynamic fields are smooth, in the sense that there are no steep gradients and no rapid changes. In fluids and gases this is the domain of the equations of Navier-Stokes and Fourier. Extended thermodynamics becomes relevant for rapidly varying and strongly inhomogeneous processes. Thus the propagation of high­ frequency waves, and the shape of shock waves, and the regression of small-scale fluctuation are governed by extended thermodynamics. The field equations of ordinary thermodynamics are parabolic while extended thermodynamics is governed by hyperbolic systems. The main ingredients of extended thermodynamics are • field equations of balance type, • constitutive quantities depending on the present local state and • entropy as a concave function of the state variables. This set of assumptions leads to first order quasi-linear symmetric hyperbolic systems of field equations; it guarantees the well-posedness of initial value problems and f...

  9. Development and implementation of a Variable Infiltration Capacity model of surface hydrology into the General Circulation Model

    International Nuclear Information System (INIS)

    Lettenmaier, D.P.; Stamm, J.F.; Wood, E.F.

    1993-04-01

    A Variable Infiltration Capacity (VIC) model is described for the representation of land surface hydrology in General Circulation Models (GCMs). The VIC model computes runoff as a function of the distribution of soil moisture capacity within a GCM grid cell. The major distinguishing feature of the VIC model relative to the bucket model currently used to represent the land surface in many GCMs is that it parameterizes the nonlinearity of the fraction of precipitation that infiltrates over a large area (hence the production of direct runoff) as a function of spatial average soil moisture storage, and that it models subsurface runoff between storms via a simple recession mechanism. The VIC model was incorporated into the Geophysical Fluid Dynamics Laboratory (GFDL) GCM at R15 resolution (roughly 4.5 degrees latitude by 7.5 degrees longitude). Ten-year simulations of global climate were produced using the GFDL GCM with both VIC land surface hydrology, and, for comparison purposes, the standard bucket representation. Comparison of the ten year runs using the VIC model with those using bucket hydrology showed that for the VIC run, global average runoff increased, soil moisture decreased, evaporation decreased, land surface temperature increased, and precipitation decreased. As expected, changes in precipitation occurred primarily over the continents, especially in the northern hemisphere. Changes in the surface water balance for Africa, Australia, and South America were much less than for North American and Eurasia. Both VIC and bucket simulations of surface air temperature and precipitation were compared with gridded monthly average observation fields. These comparisons indicated that the VIC hydrology reproduced winter temperatures better, and summer temperatures worse, than the bucket model. The VIC hydrology better represented global precipitation, primarily as a result of partially reducing the upward bias in precipitation associated with the GFDL R15 bucket runs

  10. Surface Freshwater Storage and Variability in the Amazon Basin from Multi-Satellite Observations, 1993-2007

    Science.gov (United States)

    Papa, Fabrice; Frappart, Frederic; Guntner, Andreas; Prigent, Catherine; Aires, Filipe; Getirana, Augusto; Maurer, Raffael

    2013-01-01

    The amount of water stored and moving through the surface water bodies of large river basins (river, floodplains, wetlands) plays a major role in the global water and biochemical cycles and is a critical parameter for water resources management. However, the spatio-temporal variations of these freshwater reservoirs are still widely unknown at the global scale. Here, we propose a hypsographic curve approach to estimate surface freshwater storage variations over the Amazon basin combining surface water extent from a multi-satellite-technique with topographic data from the Global Digital Elevation Model (GDEM) from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Monthly surface water storage variations for 1993-2007 are presented, showing a strong seasonal and interannual variability, and are evaluated against in situ river discharge and precipitation. The basin-scale mean annual amplitude of approx. 1200 cu km is in the range of previous estimates and contributes to about half of the Gravity Recovery And Climate Experiment (GRACE) total water storage variations. For the first time, we map the surface water volume anomaly during the extreme droughts of 1997 (October-November) and 2005 (September-October) and found that during these dry events the water stored in the river and flood-plains of the Amazon basin was, respectively, approx. 230 (approx. 40%) and 210 (approx. 50%) cu km below the 1993-2007 average. This new 15year data set of surface water volume represents an unprecedented source of information for future hydrological or climate modeling of the Amazon. It is also a first step toward the development of such database at the global scale.

  11. Fluorescent protein-mediated colour polymorphism in reef corals: multicopy genes extend the adaptation/acclimatization potential to variable light environments.

    Science.gov (United States)

    Gittins, John R; D'Angelo, Cecilia; Oswald, Franz; Edwards, Richard J; Wiedenmann, Jörg

    2015-01-01

    The genomic framework that enables corals to adjust to unfavourable conditions is crucial for coral reef survival in a rapidly changing climate. We have explored the striking intraspecific variability in the expression of coral pigments from the green fluorescent protein (GFP) family to elucidate the genomic basis for the plasticity of stress responses among reef corals. We show that multicopy genes can greatly increase the dynamic range over which corals can modulate transcript levels in response to the light environment. Using the red fluorescent protein amilFP597 in the coral Acropora millepora as a model, we demonstrate that its expression increases with light intensity, but both the minimal and maximal gene transcript levels vary markedly among colour morphs. The pigment concentration in the tissue of different morphs is strongly correlated with the number of gene copies with a particular promoter type. These findings indicate that colour polymorphism in reef corals can be caused by the environmentally regulated expression of multicopy genes. High-level expression of amilFP597 is correlated with reduced photodamage of zooxanthellae under acute light stress, supporting a photoprotective function of this pigment. The cluster of light-regulated pigment genes can enable corals to invest either in expensive high-level pigmentation, offering benefits under light stress, or to rely on low tissue pigment concentrations and use the conserved resources for other purposes, which is preferable in less light-exposed environments. The genomic framework described here allows corals to pursue different strategies to succeed in habitats with highly variable light stress levels. In summary, our results suggest that the intraspecific plasticity of reef corals' stress responses is larger than previously thought. © 2014 The Authors Molecular Ecology Published by John Wiley & Sons Ltd.

  12. Decadal variability in core surface flows deduced from geomagnetic observatory monthly means

    DEFF Research Database (Denmark)

    Whaler, K. A.; Olsen, Nils; Finlay, Chris

    2016-01-01

    . On the annual to decadal timescale, the SV is generated primarily by advection in the fluid outer core. We demonstrate the utility of the revised monthly means by calculating models of the core surface advective flow between 1997 and 2013 directly from the SV data. One set of models assumes flow......Monthly means of the magnetic field measurements at ground observatories are a key data source for studying temporal changes of the core magnetic field. However, when they are calculated in the usual way, contributions of external (magnetospheric and ionospheric) origin may remain, which make them...... less favourable for studying the field generated by dynamo action in the core. We remove external field predictions, including a new way of characterising the magnetospheric ring current, from the data and then calculate revised monthly means using robust methods. The geomagnetic secular variation (SV...

  13. Deriving inertial wave characteristics from surface drifter velocities: Frequency variability in the Tropical Pacific

    Science.gov (United States)

    Poulain, Pierre-Marie; Luther, Douglas S.; Patzert, William C.

    1992-11-01

    Two techniques have been developed for estimating statistics of inertial oscillations from satellite-tracked drifters. These techniques overcome the difficulties inherent in estimating such statistics from data dependent upon space coordinates that are a function of time. Application of these techniques to tropical surface drifter data collected during the NORPAX, EPOCS, and TOGA programs reveals a latitude-dependent, statistically significant "blue shift" of inertial wave frequency. The latitudinal dependence of the blue shift is similar to predictions based on "global" internal wave spectral models, with a superposition of frequency shifting due to modification of the effective local inertial frequency by the presence of strongly sheared zonal mean currents within 12° of the equator.

  14. Development of Surface-Variable Polymeric Nanoparticles for Drug Delivery to Tumors.

    Science.gov (United States)

    Han, Ning; Pang, Liang; Xu, Jun; Hyun, Hyesun; Park, Jinho; Yeo, Yoon

    2017-05-01

    To develop nanoparticle drug carriers that interact with cells specifically in the mildly acidic tumor microenvironment, we produced polymeric nanoparticles modified with amidated TAT peptide via a simple surface modification method. Two types of core poly(lactic-co-glycolic acid) nanoparticles (NL and NP) were prepared with a phospholipid shell as an optional feature and covered with polydopamine that enabled the conjugation of TAT peptide on the surface. Subsequent treatment with acid anhydrides such as cis-aconitic anhydride (CA) and succinic anhydride (SA) converted amines of lysine residues in TAT peptide to β-carboxylic amides, introducing carboxylic groups that undergo pH-dependent protonation and deprotonation. The nanoparticles modified with amidated TAT peptide (NLpT-CA and NPpT-CA) avoided interactions with LS174T colon cancer cells and J774A.1 macrophages at pH 7.4 but restored the ability to interact with LS174T cells at pH 6.5, delivering paclitaxel efficiently to the cells following a brief contact time. In LS174T tumor-bearing nude mice, NPpT-CA showed less accumulation in the lung than NPpT, reflecting the shielding effect of amidation, but tumor accumulation of NPpT and NPpT-CA was equally minimal. Comparison of particle stability and protein corona formation in media containing sera from different species suggests that NPpT-CA has been activated and opsonized in mouse blood to a greater extent than those in bovine serum-containing medium, thus losing the benefits of pH-sensitivity expected from in vitro experiments.

  15. Overview of surface ozone variability in East Asia-North Pacific region during IGAC/APARE (1994--1996).

    Science.gov (United States)

    Lam, K S; Wang, T J; Wang, T; Tang, J; Kajii, Y; Liu, C M; Shim, S G

    2004-01-01

    Surface ozone (O3) was measured at Oki Island (Japan), Cheju Island (South Korea), Lanyu Island (Taiwan Province, China), Cape D'Aguilar (Hong Kong SAR) and Lin'an, Longfenshan, Waliguan (China mainland) during January 1994--December 1996 as a component of IGAC/APARE (International Global Atmospheric Chemistry/East Asia-North Pacific Regional Experiment). This paper gave a joint discussion on the observational results at these stations over the study region. Investigations showed that the average of surface O3 mixing ratios at the seven sites are 47.9+/-15.8, 48.1+/-17.9, 30.2+/-16.4, 31.6+/-17.5, 36.3+/-17.5, 34.8+/-11.5 and 48.2+/-9.5 ppbv, respectively. Significant diurnal variations of surface O3 have been observed at Oki, Cheju, D'Aguilar, Lin'an and Longfenshan. Their annual averaged diurnal differences range from 8 to 23 ppbv and differ in each season. Surface O3 at Lanyu and Waliguan do not show strong diurnal variability. Seasonal cycles of surface O3 showed difference at the temperate and the subtropical remote sites. Oki has a summer minimum-spring maximum, while Lanyu has a summer minimum-autumn maximum. The suburban sites at D'Aguilar and Lin'an report high-level O3 in autumn and low level O3 in summer. Surface O3 remains-high in autumn and low in winter at the rural site Longfenshan. For the global background station Waliguan, surface O3 exhibits a broad spring-summer maximum and autumn-winter minimum. The backward air trajectories to these sites have shown different pathways of long-range transport of air pollution from East Asia Continent to North Pacific Ocean. Surface O3 was found to be strongly and positively correlated with CO at Oki and Lanyu, especially in spring and autumn, reflecting the substantial photochemical buildup of O3 on a regional scale. It is believed that the regional sources of pollution in East Asia have enhanced the average surface O3 concentrations in the background atmosphere of North Pacific.

  16. Local Versus Remote Contributions of Soil Moisture to Near-Surface Temperature Variability

    Science.gov (United States)

    Koster, R.; Schubert, S.; Wang, H.; Chang, Y.

    2018-01-01

    Soil moisture variations have a straightforward impact on overlying air temperatures, wetter soils can induce higher evaporative cooling of the soil and thus, locally, cooler temperatures overall. Not known, however, is the degree to which soil moisture variations can affect remote air temperatures through their impact on the atmospheric circulation. In this talk we describe a two-pronged analysis that addresses this question. In the first segment, an extensive ensemble of NASA/GSFC GEOS-5 atmospheric model simulations is analyzed statistically to isolate and quantify the contributions of various soil moisture states, both local and remote, to the variability of air temperature at a given local site. In the second segment, the relevance of the derived statistical relationships is evaluated by applying them to observations-based data. Results from the second segment suggest that the GEOS-5-based relationships do, at least to first order, hold in nature and thus may provide some skill to forecasts of air temperature at subseasonal time scales, at least in certain regions.

  17. On the behavior of surface electromyographic variables during the menstrual cycle

    International Nuclear Information System (INIS)

    Soares, Fabiano Araujo; Salomoni, Sauro Emerick; De Carvalho, Joao Luiz Azevedo; Nascimento, Francisco Assis de Oliveira; Veneziano, Wilson Henrique; Pires, Kenia Fonseca; Da Rocha, Adson Ferreira

    2011-01-01

    The goal of this work is to study the behavior of electromyographic variables during the menstrual cycle. Ten female volunteers (24.0 ± 2.8 years of age) performed fatiguing isometric contractions, and electromyographic signals were measured on the biceps brachii in four phases of the menstrual cycle. Adaptations of classical algorithms were used for the estimation of the root mean square (RMS) value, absolute rectified value (ARV), mean frequency (MNF), median frequency (MDF), and conduction velocity (CV). The CV estimator had a higher (p = 0.002) rate of decrease at the end of the follicular phase and at the end of the luteal phase. The MDF (p = 0.002) and MNF (p = 0.004) estimators had a higher rate of decrease at the beginning of the follicular phase and at the end of the luteal phase. No significant differences between phases of the menstrual cycle were detected with the ARV and RMS estimators (p > 0.05). These results suggest that the behavior of the muscles in women presents different characteristics during different phases of the menstrual cycle. In particular, women were more susceptible to fatigue at the end of the luteal phase

  18. Compositional changes of surface sediments and variability of manganese nodules in the Peru Basin

    Science.gov (United States)

    Marchig, Vesna; von Stackelberg, Ulrich; Hufnagel, Heinz; Durn, Goran

    Two types of manganese nodules were observed in the Peru Basin: large botryoidal nodules in basins and small ellipsoidal nodules on slope positions. The sediment in areas with large botryoidal nodules contains a thinner and weaker oxidation zone than the sediment under small ellipsoidal nodules, indicating that diagenetic processes in the sediment, which supply manganese nodules with metals for their growth, are stronger in sediments on which large botryoidal nodules grow. Organic matter, which activates remobilization of metals, occurs mostly in the form of refractory lipidic compounds in the inner capsule of radiolaria. This material needs bacterial degradation to act as a reducing agent. Easily oxidizable organic components could not be found in the sediments. Other changes in sediment composition do not have a link to manganese nodule growth. Biogenous components (radiolarians, organogenic barite and apatite) increase towards the equatorial high-productivity zone. Authigenous clay minerals (nontronite as well as montmorillonite with high Fe +3 incorporation on positions of ochtaedral Al) increase with distance from the continent. The assessment of environmental impacts will have to take into account the regional differences in sediment composition and the small-scale variability of manganese nodules.

  19. The impacts of urban surface characteristics on radiation balance and meteorological variables in the boundary layer around Beijing in summertime

    Science.gov (United States)

    Liu, Ruiting; Han, Zhiwei; Wu, Jian; Hu, Yonghong; Li, Jiawei

    2017-11-01

    In this study, some key geometric and thermal parameters derived from recent field and satellite observations in Beijing were collected and incorporated into WRF-UCM (Weather Research and Forecasting) model instead of previous default ones. A series of sensitivity model simulations were conducted to investigate the influences of these parameters on radiation balance, meteorological variables, turbulence kinetic energy (TKE), as well as planetary boundary layer height (PBLH) in regions around Beijing in summer 2014. Model validation demonstrated that the updated parameters represented urban surface characteristics more realistically and the simulations of meteorological variables were evidently improved to be closer to observations than the default parameters. The increase in building height tended to increase and slightly decrease surface air temperature at 2 m (T2) at night and around noon, respectively, and to reduce wind speed at 10 m (WS10) through a day. The increase in road width led to significant decreases in T2 and WS10 through the whole day, with the maximum changes in early morning and in evening, respectively. Both lower surface albedo and inclusion of anthropogenic heat (AH) resulted in increases in T2 and WS10 over the day, with stronger influence from AH. The vertical extension of the impact of urban surface parameters was mainly confined within 300 m at night and reached as high as 1600 m during daytime. The increase in building height tended to increase TKE and PBLH and the TKE increase was larger at night than during daytime due to enhancements of both mechanical and buoyant productions. The increase in road width generally reduced TKE and PBLH except for a few hours in the afternoon. The lower surface albedo and the presence of AH consistently resulted in increases of TKE and PBLH through both day and night. The increase in building height induced a slight divergence by day and a notable convergence at night, whereas the increase in road width

  20. Quantifying the influence of land-use and surface characteristics on spatial variability in the urban heat island

    Science.gov (United States)

    Hart, Melissa A.; Sailor, David J.

    2009-03-01

    The urban thermal environment varies not only from its rural surroundings but also within the urban area due to intra-urban differences in land-use and surface characteristics. Understanding the causes of this intra-urban variability is a first step in improving urban planning and development. Toward this end, a method for quantifying causes of spatial variability in the urban heat island has been developed. This paper presents the method as applied to a specific test case of Portland, Oregon. Vehicle temperature traverses were used to determine spatial differences in summertime ~2 m air temperature across the metropolitan area in the afternoon. A tree-structured regression model was used to quantify the land-use and surface characteristics that have the greatest influence on daytime UHI intensity. The most important urban characteristic separating warmer from cooler regions of the Portland metropolitan area was canopy cover. Roadway area density was also an important determinant of local UHI magnitudes. Specifically, the air above major arterial roads was found to be warmer on weekdays than weekends, possibly due to increased anthropogenic activity from the vehicle sector on weekdays. In general, warmer regions of the city were associated with industrial and commercial land-use. The downtown core, whilst warmer than the rural surroundings, was not the warmest part of the Portland metropolitan area. This is thought to be due in large part to local shading effects in the urban canyons.

  1. Extending Puppet

    CERN Document Server

    Franceschi, Alessandro

    2014-01-01

    This book is a clear, detailed and practical guide to learn about designing and deploying you puppet architecture, with informative examples to highlight and explain concepts in a focused manner. This book is designed for users who already have good experience with Puppet, and will surprise experienced users with innovative topics that explore how to design, implement, adapt, and deploy a Puppet architecture. The key to extending Puppet is the development of types and providers, for which you must be familiar with Ruby.

  2. Simulated interannual variability of the Greenland Sea deep water formation and its connection to surface forcing

    Science.gov (United States)

    Haekkinen, Sirpa

    1995-01-01

    A fully prognostic Arctic ice-ocean model is used to study the interannual variability of deepwater formation in the Greenland Sea Gyre based on the simulations for the Arctic ice-ocean system for the period 1955 and 1960 - 1985. The model uses monthly climatology for thermodynamic forcing components (such as air temperature and cloudiness), together with constant annual net precipitation and river runoff. The daily wind forcing is derived from analyzed sea level air pressures from the National Center for Atmospheric Research (NCAR). In summary, the model shows that the occurence of deep convection in the Greenland Sea Gyre is controlled by the extensive Fram Strait ice export and/or local wind conditions in the Greenland Sea. In the latter case the weakening of the local wind curl allows the Polar Front to move eastward. The movement of the Polar Front causes adverse ice conditions, often together with much larger than normal ice export from the Arctic, such as in 1968, which can block convection in the gyre. The density difference between upper and lower layers is investigated as an indication of water mass formation through convection, occurring as strong diffusion in the model. The model-simulated density difference between the average top 100 m and deep levels reveals that the period 1960 - 1985 had only a few distinct years with weak stratification, and, especially, the model predicts no deep convection since the nid-1970s. The common factor for the years of the weakest decrease of the model-predicted heat content of the upper 2000 m which can, to a high degree, be explained by local heat loss.

  3. SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA

    Energy Technology Data Exchange (ETDEWEB)

    Scargle, Jeffrey D.; Worden, Simon P. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Keil, Stephen L. [National Solar Observatory, P.O. Box 57, Sunspot, NM 88349 (United States)

    2013-07-01

    Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

  4. A Conceptual Model for Spatial Grain Size Variability on the Surface of and within Beaches

    Directory of Open Access Journals (Sweden)

    Edith Gallagher

    2016-05-01

    Full Text Available Grain size on the surface of natural beaches has been observed to vary spatially and temporally with morphology and wave energy. The stratigraphy of the beach at Duck, North Carolina, USA was examined using 36 vibracores (~1–1.5 m long collected along a cross-shore beach profile. Cores show that beach sediments are finer (~0.3 mm and more uniform high up on the beach. Lower on the beach, with more swash and wave action, the sand is reworked, segregated by size, and deposited in layers and patches. At the deepest measurement sites in the swash (~−1.4 to −1.6 m NAVD88, which are constantly being reworked by the energetic shore break, there is a thick layer (60–80 cm of very coarse sediment (~2 mm. Examination of two large trenches showed that continuous layers of coarse and fine sands comprise beach stratigraphy. Thicker coarse layers in the trenches (above mean sea level are likely owing to storm erosion and storm surge elevating the shore break and swash, which act to sort the sediment. Those layers are buried as water level retreats, accretion occurs and the beach recovers from the storm. Thinner coarse layers likely represent similar processes acting on smaller temporal scales.

  5. Innervation zone of the vastus medialis muscle: position and effect on surface EMG variables

    International Nuclear Information System (INIS)

    Gallina, A; Merletti, R; Gazzoni, M

    2013-01-01

    The aim of this study was to investigate the position of the innervation zone (IZ) of the vastus medialis (VM) and its effect on the electromyographic (EMG) amplitude and mean frequency estimates. Eighteen healthy subjects performed maximal isometric knee extensions at three knee angles. Surface EMG signals were collected by using a 16 × 8 electrode grid placed on the VM muscle. The position of the IZ was estimated through visual analysis, and traditional bipolar signals were obtained from channels over and away from it; amplitude and mean frequency values were extracted and compared using an analysis of variance (ANOVA) with repeated measures. The IZ is shaped as a line running from the proximal–lateral to the distal–medial aspect of the VM muscle. The presence of an IZ under the electrodes lowered the EMG amplitude (P < 0.001, F = 58.11) and increased the EMG mean frequency (P < 0.001, F = 26.47); variations of these parameters due to the knee flexion angle were less frequently observed in EMG signals collected over than away from the IZ. Electrodes placed ‘over the belly of the VM muscle’ are likely to collect EMG signals influenced by the presence of the IZ, thus hindering the detection of changes in muscle activity. (paper)

  6. Variability of Solar Radiation and CDOM in Surface Coastal Waters of the Northwestern Mediterranean Sea.

    Science.gov (United States)

    Sempéré, Richard; Para, Julien; Tedetti, Marc; Charrière, Bruno; Mallet, Marc

    2015-01-01

    Atmospheric and in-water solar radiation, including UVR-B, UVR-A and PAR, as well as chromophoric dissolved organic matter absorption [aCDOM (λ)] in surface waters were monthly measured from November 2007 to December 2008 at a coastal station in the Northwestern Mediterranean Sea (Bay of Marseilles, France). Our results showed that the UVR-B/UVR-A ratio followed the same trend in the atmosphere and at 2 m depth in the water (P CDOM contributed to UVR attenuation in the UVA domain, but also played a significant role in PAR attenuation. Mean UV doses received in the mixed layer depth were higher by a factor 1.4-33 relative to doses received at fixed depths (5 and 10 m) in summer (stratified period), while the inverse pattern was found in winter (mixing period). This shows the importance of taking into account the vertical mixing in the evaluation of UVR effects on marine organisms. © 2015 The American Society of Photobiology.

  7. Holocene Millennial-scale Surface and Bottom Water Variability, Feni Drift, NE Atlantic Ocean: Foraminiferal Assemblages

    Science.gov (United States)

    Lassen, S. J.; Richter, T. O.; de Stigter, H. C.; van Weering, T. C. E.; de Haas, H.

    A high-resolution sediment core from Feni Drift (ENAM9606, 56N 14W, 2543 m wa- ter depth) was investigated for planktonic and benthic foraminiferal assemblages dur- ing the last 12,000 years. During the Preboreal, peak abundances of T.quinqueloba indicate the passage of the Arctic front over the core site. Holocene planktonic foraminiferal assemblages indicate a gradual warming trend of surface water masses punctuated by a major cooling (8,200ky event s.l.), and possibly a slight cooling dur- ing the last 3,000 years. The interval from 10 to 5kyrs shows higher and fluctuating abundances of T.quinqueloba and G.bulloides, which suggest proximity of the subarc- tic front and enhanced spring blooms compared to the upper Holocene. Abundance peaks of N.pachyderma(s) and/or T.quinqueloba indicate a series of millennial-scale cooling events during the entire Holocene, which can be correlated to similar episodes previously described from other locations in the North Atlantic and Norwegian- Greenland Sea. Benthic foraminiferal assemblages indicate a gradual transition from seasonal, spring-bloom related food supply in the Lower Holocene (dominance of the phytodetritus species E.exigua) to possibly lower, but more sustained food supply in the Upper Holocene (dominance of C.obtusa and C.laevigata).

  8. Transcriptional regulation of the Borrelia burgdorferi antigenically variable VlsE surface protein.

    Science.gov (United States)

    Bykowski, Tomasz; Babb, Kelly; von Lackum, Kate; Riley, Sean P; Norris, Steven J; Stevenson, Brian

    2006-07-01

    The Lyme disease agent Borrelia burgdorferi can persistently infect humans and other animals despite host active immune responses. This is facilitated, in part, by the vls locus, a complex system consisting of the vlsE expression site and an adjacent set of 11 to 15 silent vls cassettes. Segments of nonexpressed cassettes recombine with the vlsE region during infection of mammalian hosts, resulting in combinatorial antigenic variation of the VlsE outer surface protein. We now demonstrate that synthesis of VlsE is regulated during the natural mammal-tick infectious cycle, being activated in mammals but repressed during tick colonization. Examination of cultured B. burgdorferi cells indicated that the spirochete controls vlsE transcription levels in response to environmental cues. Analysis of PvlsE::gfp fusions in B. burgdorferi indicated that VlsE production is controlled at the level of transcriptional initiation, and regions of 5' DNA involved in the regulation were identified. Electrophoretic mobility shift assays detected qualitative and quantitative changes in patterns of protein-DNA complexes formed between the vlsE promoter and cytoplasmic proteins, suggesting the involvement of DNA-binding proteins in the regulation of vlsE, with at least one protein acting as a transcriptional activator.

  9. Optimization of process variables on flexural properties of epoxy/organo-montmorillonite nanocomposite by response surface methodology

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available This study attempted to investigate the preparation and optimization of the flexural properties for epoxy/organomontmorillonite (OMMT nanocomposites. In-situ polymerization method was used to prepare epoxy/OMMT nanocomposites. The diglycidyl ether bisphenol A (DGEBA and curing agent were mixed first, followed by the addition of OMMT. In this study, computer aided statistical methods of experimental design (Response Surface Methodology, RSM was used to investigate the process variables on the flexural properties of epoxy/4wt% OMMT nanocomposites. Speed of mechanical stirrer, post-curing time and post-curing temperature were chosen as process variables in the experimental design. Results showed that the speed of mechanical stirrer, post-curing time and post-curing temperature were able to influence the flexural modulus and flexural yield stress of epoxy/4 wt% OMMT nanocomposites. The results of optimization showed that the design of experiment (DOE has six combination of operating variables which have been obtained in order to attain the greatest overall desirability.

  10. Diurnal and vertical variability of the sensible heat and carbon dioxide budgets in the atmospheric surface layer

    International Nuclear Information System (INIS)

    Casso-Torralba, P.; Rosa Soler, M.; Vila-Guerau de Arellano, J.; Bosveld, F.; Vermeulen, A.; Werner, C.; Moors, E.

    2008-08-01

    The diurnal and vertical variability of heat and carbon dioxide (CO2) in the atmospheric surface layer are studied by analyzing measurements from a 213 m tower in Cabauw (Netherlands). Observations of thermodynamic variables and CO2 mixing ratio as well as vertical profiles of the turbulent fluxes are used to retrieve the contribution of the budget terms in the scalar conservation equation. On the basis of the daytime evolution of turbulent fluxes, we calculate the budget terms by assuming that turbulent fluxes follow a linear profile with height. This assumption is carefully tested and the deviation from linearity is quantified. The budget calculation allows us to assess the importance of advection of heat and CO2 during day hours for three selected days. It is found that, under nonadvective conditions, the diurnal variability of temperature and CO2 is well reproduced from the flux divergence measurements. Consequently, the vertical transport due to the turbulent flux plays a major role in the daytime evolution of both scalars and the advection is a relatively small contribution. During the analyzed days with a strong contribution of advection of either heat or carbon dioxide, the flux divergence is still an important contribution to the budget. For heat, the quantification of the advection contribution is in close agreement with results from a numerical model. For carbon dioxide, we qualitatively corroborate the results with a Lagrangian transport model. Our estimation of advection is compared with traditional estimations based on the Net Ecosystem-atmosphere Exchange (NEE)

  11. Response of groundwater level and surface-water/groundwater interaction to climate variability: Clarence-Moreton Basin, Australia

    Science.gov (United States)

    Cui, Tao; Raiber, Matthias; Pagendam, Dan; Gilfedder, Mat; Rassam, David

    2018-03-01

    Understanding the response of groundwater levels in alluvial and sedimentary basin aquifers to climatic variability and human water-resource developments is a key step in many hydrogeological investigations. This study presents an analysis of groundwater response to climate variability from 2000 to 2012 in the Queensland part of the sedimentary Clarence-Moreton Basin, Australia. It contributes to the baseline hydrogeological understanding by identifying the primary groundwater flow pattern, water-level response to climate extremes, and the resulting dynamics of surface-water/groundwater interaction. Groundwater-level measurements from thousands of bores over several decades were analysed using Kriging and nonparametric trend analysis, together with a newly developed three-dimensional geological model. Groundwater-level contours suggest that groundwater flow in the shallow aquifers shows local variations in the close vicinity of streams, notwithstanding general conformance with topographic relief. The trend analysis reveals that climate variability can be quickly reflected in the shallow aquifers of the Clarence-Moreton Basin although the alluvial aquifers have a quicker rainfall response than the sedimentary bedrock formations. The Lockyer Valley alluvium represents the most sensitively responding alluvium in the area, with the highest declining (-0.7 m/year) and ascending (2.1 m/year) Sen's slope rates during and after the drought period, respectively. Different surface-water/groundwater interaction characteristics were observed in different catchments by studying groundwater-level fluctuations along hydrogeologic cross-sections. The findings of this study lay a foundation for future water-resource management in the study area.

  12. The impact of inter-annual variability of annual cycle on long-term persistence of surface air temperature in long historical records

    Science.gov (United States)

    Deng, Qimin; Nian, Da; Fu, Zuntao

    2018-02-01

    Previous studies in the literature show that the annual cycle of surface air temperature (SAT) is changing in both amplitude and phase, and the SAT departures from the annual cycle are long-term correlated. However, the classical definition of temperature anomalies is based on the assumption that the annual cycle is constant, which contradicts the fact of changing annual cycle. How to quantify the impact of the changing annual cycle on the long-term correlation of temperature anomaly variability still remains open. In this paper, a recently developed data adaptive analysis tool, the nonlinear mode decomposition (NMD), is used to extract and remove time-varying annual cycle to reach the new defined temperature anomalies in which time-dependent amplitude of annual cycle has been considered. By means of detrended fluctuation analysis, the impact induced by inter-annual variability from the time-dependent amplitude of annual cycle has been quantified on the estimation of long-term correlation of long historical temperature anomalies in Europe. The results show that the classical climatology annual cycle is supposed to lack inter-annual fluctuation which will lead to a maximum artificial deviation centering around 600 days. This maximum artificial deviation is crucial to defining the scaling range and estimating the long-term persistence exponent accurately. Selecting different scaling range could lead to an overestimation or underestimation of the long-term persistence exponent. By using NMD method to extract the inter-annual fluctuations of annual cycle, this artificial crossover can be weakened to extend a wider scaling range with fewer uncertainties.

  13. Temporal and spatial patterns of wetland extent influence variability of surface water connectivity in the Prairie Pothole Region, United States

    Science.gov (United States)

    Vanderhoof, Melanie; Alexander, Laurie C.; Todd, Jason

    2016-01-01

    Context. Quantifying variability in landscape-scale surface water connectivity can help improve our understanding of the multiple effects of wetlands on downstream waterways. Objectives. We examined how wetland merging and the coalescence of wetlands with streams varied both spatially (among ecoregions) and interannually (from drought to deluge) across parts of the Prairie Pothole Region. Methods. Wetland extent was derived over a time series (1990-2011) using Landsat imagery. Changes in landscape-scale connectivity, generated by the physical coalescence of wetlands with other surface water features, were quantified by fusing static wetland and stream datasets with Landsat-derived wetland extent maps, and related to multiple wetness indices. The usage of Landsat allows for decadal-scale analysis, but limits the types of surface water connections that can be detected. Results. Wetland extent correlated positively with the merging of wetlands and wetlands with streams. Wetness conditions, as defined by drought indices and runoff, were positively correlated with wetland extent, but less consistently correlated with measures of surface water connectivity. The degree of wetland-wetland merging was found to depend less on total wetland area or density, and more on climate conditions, as well as the threshold for how wetland/upland was defined. In contrast, the merging of wetlands with streams was positively correlated with stream density, and inversely related to wetland density. Conclusions. Characterizing the degree of surface water connectivity within the Prairie Pothole Region in North America requires consideration of 1) climate-driven variation in wetness conditions and 2) within-region variation in wetland and stream spatial arrangements.

  14. 1990-2016 surface solar radiation variability and trend over the Piedmont region (northwest Italy)

    Science.gov (United States)

    Manara, Veronica; Bassi, Manuela; Brunetti, Michele; Cagnazzi, Barbara; Maugeri, Maurizio

    2018-05-01

    A new surface solar radiation database of 74 daily series is set up for the Piedmont region (northwest Italy) for the 1990-2016 period. All the series are subjected to a detailed quality control, homogenization and gap-filling procedure and are transformed into relative annual/seasonal anomaly series. Finally, a gridded version (0.5°×0.5°) of the database is generated. The resulting series show an increasing tendency of about + 2.5% per decade at annual scale, with strongest trend in autumn (+ 4% per decade). The only exception is winter, showing a negative but not significant trend. Considering the plain and mountain mean series, the trends are more intense for low than for high elevations with a negative vertical gradient of about - 0.03% per decade per 100 m at annual scale and values up to - 0.07% per decade per 100 m in spring. Focusing on clear days only (selected by CM SAF ClOud fractional cover dataset from METeosat first and second generation—Edition 1 satellite data over the 1991-2015 period), trend significance strongly increases and both low and high elevation records exhibit a positive trend in all seasons. However, the trends result slightly lower than for all-sky days (with the only exception of winter). The differences observed under clear-sky conditions between low and high elevations are more pronounced in winter, where the trend shows a negative vertical gradient of about - 0.1% per decade every 100 m. Overall, this paper shows how a high station density allows performing a more detailed quality control thanks to the higher performances in detecting the inhomogeneities with higher data availability and capturing regional peculiarities otherwise impossible to observe.

  15. Adsorption of Polyanion onto Large Alpha Alumina Beads with Variably Charged Surface

    Directory of Open Access Journals (Sweden)

    Tien Duc Pham

    2014-01-01

    Full Text Available Adsorption of strong polyelectrolyte, poly(styrenesulfonate, PSS, of different molecular weights onto large α-Al2O3 beads was systematically investigated as functions of pH and NaCl concentrations. The ultraviolet (UV absorption spectra of PSS at different pH and salt concentrations confirmed that the structure of PSS is independent of pH. With the change of molecular weight from 70 kg/mol (PSS 70 to 1000 kg/mol (PSS 1000, adsorption amount of PSS increases and proton coadsorption on the surface of α-Al2O3 decreases at given pH and salt concentration. It suggests that higher molecular weight of PSS was less flat conformation than lower one. The adsorption density of PSS 70 and PSS 1000 decreases with decreasing salt concentrations, indicating that both electrostatic and nonelectrostatic interactions are involved. Experimental results of both PSS 70 and PSS 1000 adsorption isotherms onto α-Al2O3 at different pH and salt concentrations can be represented well by two-step adsorption model. The effects of molecular weight and salt concentration are explained by structure of adsorbed PSS onto α-Al2O3. The influence of added SDS on the isotherms is evaluated from the sequential adsorption. The SDS uptake onto α-Al2O3 in the presence of hemimicelles can prevent the adsorption of PSS at low concentration so that adsorption of PSS reduces with preadsorbed SDS.

  16. Mid-Piacenzian Variability of Nordic Seas Surface Circulation Linked to Terrestrial Climatic Change in Norway

    Science.gov (United States)

    Panitz, Sina; De Schepper, Stijn; Salzmann, Ulrich; Bachem, Paul E.; Risebrobakken, Bjørg; Clotten, Caroline; Hocking, Emma P.

    2017-12-01

    During the mid-Piacenzian, Nordic Seas sea surface temperatures (SSTs) were higher than today. While SSTs provide crucial climatic information, on their own they do not allow a reconstruction of potential underlying changes in water masses and currents. A new dinoflagellate cyst record for Ocean Drilling Program (ODP) Site 642 is presented to evaluate changes in northward heat transport via the Norwegian Atlantic Current (NwAC) between 3.320 and 3.137 Ma. The record is compared with vegetation and SST reconstructions from Site 642 and SSTs from Iceland Sea ODP Site 907 to identify links between SSTs, ocean currents, and vegetation changes. The dinocyst record shows that strong Atlantic water influence via the NwAC corresponds to higher-than-present SSTs and cool temperate vegetation during Marine Isotope Stage (MIS) transition M2-M1 and KM5. Reduced Atlantic water inflow relative to the warm stages coincides with near-modern SSTs and boreal vegetation during MIS M2, KM6, and KM4-KM2. During most of the studied interval, a strong SST gradient between Sites 642 and 907 indicates the presence of a proto-Arctic Front (AF). An absent gradient during the first half of MIS KM6, due to reduced Atlantic water influence at Site 642 and warm, presumably Atlantic water reaching Site 907, is indicative of a weakened NwAC and East Greenland Current. We conclude that repeated changes in Atlantic water influence directly affect terrestrial climate and that an active NwAC is needed for an AF to develop. Obliquity forcing may have played a role, but the correlation is not consistent.

  17. Variability of Surface pollutants and aerosol concentration over Abu Dhabi, UAE - sources, transport and current levels

    Science.gov (United States)

    Phanikumar, Devulapalli V.; Basha, Ghouse; Ouarda, Taha B. M. J.

    2015-04-01

    In the view of recent economic, industrial, and rapid development, Abu Dhabi (24.4oN; 54.4oE; 27m msl) has become one of the most populated regions in the world despite of extreme heat, frequent dust storms, and with distinctive topography. The major sources of air pollution are from the dust and sand storms, greenhouse gas emissions, and to some extent from industrial pollution. In order to realize the accurate and comprehensive understanding of air quality and plausible sources over this region, we have made a detailed analysis of three years simultaneous measurements during 2011-13 of pollutants such as O3, SO2, NO2, CO, and PM10 concentrations. Diurnal variation of meteorological parameters such as temperature and wind speed/relative humidity clearly shows daytime maximum/minimum in summer followed by pre-monsoon, post-monsoon and winter. The prevailing winds over this region are mostly from northwesterly direction (Shamal wind). Diurnal wind pattern showed a clear contrast with the majority of the wind pattern during nighttime and early morning is from the westerly/northwesterly and daytime is from southwesterly/southeasterly directions. The diurnal pattern of O3 shows minimum during 08 LT and increases thereafter reaching maximum at 17 LT and decreases during nighttime. However, the diurnal pattern of SO2 and NO2 show a peak at ~ 08 LT and dip at ~ 14 LT during all the seasons with some variability in each season. On the other hand, the diurnal pattern of CO shows a peculiar picture of elevated levels during daytime peaking at ~ 10 LT (prominent in summer and post-monsoon) followed by a sharp decrease and minimum is ~14 LT. PM10 concentration has an early morning peak at ~ 02 LT and then decreases to a minimum value at ~11 LT and again increases in the afternoon hours (maximum at ~17 LT) depicting a forenoon-afternoon asymmetry. Monthly variation of PM10 shows maximum in pre-monsoon season and minimum in winter. Our observations show the diurnal pattern of

  18. Analyzing the Relative Linkages of Land Use and Hydrologic Variables with Urban Surface Water Quality using Multivariate Techniques

    Science.gov (United States)

    Ahmed, S.; Abdul-Aziz, O. I.

    2015-12-01

    We used a systematic data-analytics approach to analyze and quantify relative linkages of four stream water quality indicators (total nitrogen, TN; total phosphorus, TP; chlorophyll-a, Chla; and dissolved oxygen, DO) with six land use and four hydrologic variables, along with the potential external (upstream in-land and downstream coastal) controls in highly complex coastal urban watersheds of southeast Florida, U.S.A. Multivariate pattern recognition techniques of principle component and factor analyses, in concert with Pearson correlation analysis, were applied to map interrelations and identify latent patterns of the participatory variables. Relative linkages of the in-stream water quality variables with their associated drivers were then quantified by developing dimensionless partial least squares (PLS) regression model based on standardized data. Model fitting efficiency (R2=0.71-0.87) and accuracy (ratio of root-mean-square error to the standard deviation of the observations, RSR=0.35-0.53) suggested good predictions of the water quality variables in both wet and dry seasons. Agricultural land and groundwater exhibited substantial controls on surface water quality. In-stream TN concentration appeared to be mostly contributed by the upstream water entering from Everglades in both wet and dry seasons. In contrast, watershed land uses had stronger linkages with TP and Chla than that of the watershed hydrologic and upstream (Everglades) components for both seasons. Both land use and hydrologic components showed strong linkages with DO in wet season; however, the land use linkage appeared to be less in dry season. The data-analytics method provided a comprehensive empirical framework to achieve crucial mechanistic insights into the urban stream water quality processes. Our study quantitatively identified dominant drivers of water quality, indicating key management targets to maintain healthy stream ecosystems in complex urban-natural environments near the coast.

  19. Response of planktonic cladocerans (Class: Branchiopoda) to short-term changes in environmental variables in the surface waters of the Bay of Biscay

    Science.gov (United States)

    d'Elbée, Jean; Lalanne, Yann; Castège, Iker; Bru, Noelle; D'Amico, Frank

    2014-08-01

    From January 2001 to December 2008, 73 surface plankton samples and 45 vertical profiles of sea temperature, salinity, dissolved oxygen and pH were collected on a monthly basis from a single sampling station located in the Bay of Biscay (43°37N; 1°43W) (North-East Atlantic). Two types of North Atlantic Oscillation (NAO) indexes were included in the data set and submitted to a Canonical Correspondence Analysis and Spearman non-parametric test. Significant breaks and levels in time series were tested using a data segmentation method. The temperature range varies from 11 °C to 25 °C. It begins to rise from April until August and then decline. Low salinity values occur in mid-spring (36 PSU) in autumn. Dissolved oxygen mean values were around 8 mg/l. In summer, when temperature and salinity are high, surface water layer is always accompanied with a significant deoxygenation, and the process reverses in winter. pH mean values range was 7.78-8.33. Seasonal and inter-annual variations of the two NAO indexes are strongly correlated to one another, but do not correlate with any hydrological or biological variable. Five of the seven cladocerans species which are present in the Bay of Biscay were found in this study. There is a strong pattern in species succession throughout the year: Evadne nordmanni is a vernal species, while Penilia avirostris and Pseudevadne tergestina occur mainly in summer and autumn. Evadne spinifera has a maximum abundance in spring, Podon intermedius in autumn, but they both occur throughout the year. However, for some thirty years, the presence of species has tended to become significantly extended throughout the year. During the 2001-2008 period, there was a noticeable decline and even a disappearance of the categories involved in sexual reproduction as well as those involved in parthenogenesis, in favor of non-breeding individuals.

  20. Variability of the reflectance coefficient of skylight from the ocean surface and its implications to ocean color.

    Science.gov (United States)

    Gilerson, Alexander; Carrizo, Carlos; Foster, Robert; Harmel, Tristan

    2018-04-16

    The value and spectral dependence of the reflectance coefficient (ρ) of skylight from wind-roughened ocean surfaces is critical for determining accurate water leaving radiance and remote sensing reflectances from shipborne, AERONET-Ocean Color and satellite observations. Using a vector radiative transfer code, spectra of the reflectance coefficient and corresponding radiances near the ocean surface and at the top of the atmosphere (TOA) are simulated for a broad range of parameters including flat and windy ocean surfaces with wind speeds up to 15 m/s, aerosol optical thicknesses of 0-1 at 440nm, wavelengths of 400-900 nm, and variable Sun and viewing zenith angles. Results revealed a profound impact of the aerosol load and type on the spectral values of ρ. Such impacts, not included yet in standard processing, may produce significant inaccuracies in the reflectance spectra retrieved from above-water radiometry and satellite observations. Implications for satellite cal/val activities as well as potential changes in measurement and data processing schemes are discussed.

  1. Processes of 30-90 days sea surface temperature variability in the northern Indian Ocean during boreal summer

    Energy Technology Data Exchange (ETDEWEB)

    Vialard, J. [Univerite P. et M. Curie, Laboratoire d' Oceanographie Experimentation et Approches Numeriques (LOCEAN), Case 100, CNRS, IRD, Paris Cedex 05 (France); Jayakumar, A.; Gnanaseelan, C.; Goswami, B.N. [Indian Institute of Tropical Meteorology, Pune (India); Lengaigne, M. [Univerite P. et M. Curie, Laboratoire d' Oceanographie Experimentation et Approches Numeriques (LOCEAN), Case 100, CNRS, IRD, Paris Cedex 05 (France); CSIR, National Institute of Oceanography, Goa (India); Sengupta, D. [Indian Institute of Sciences, Centre of Atmospheric and Oceanic Sciences, Bangalore (India)

    2012-05-15

    During summer, the northern Indian Ocean exhibits significant atmospheric intraseasonal variability associated with active and break phases of the monsoon in the 30-90 days band. In this paper, we investigate mechanisms of the Sea Surface Temperature (SST) signature of this atmospheric variability, using a combination of observational datasets and Ocean General Circulation Model sensitivity experiments. In addition to the previously-reported intraseasonal SST signature in the Bay of Bengal, observations show clear SST signals in the Arabian Sea related to the active/break cycle of the monsoon. As the atmospheric intraseasonal oscillation moves northward, SST variations appear first at the southern tip of India (day 0), then in the Somali upwelling region (day 10), northern Bay of Bengal (day 19) and finally in the Oman upwelling region (day 23). The Bay of Bengal and Oman signals are most clearly associated with the monsoon active/break index, whereas the relationship with signals near Somali upwelling and the southern tip of India is weaker. In agreement with previous studies, we find that heat flux variations drive most of the intraseasonal SST variability in the Bay of Bengal, both in our model (regression coefficient, 0.9, against {proportional_to}0.25 for wind stress) and in observations (0.8 regression coefficient); {proportional_to}60% of the heat flux variation is due do shortwave radiation and {proportional_to}40% due to latent heat flux. On the other hand, both observations and model results indicate a prominent role of dynamical oceanic processes in the Arabian Sea. Wind-stress variations force about 70-100% of SST intraseasonal variations in the Arabian Sea, through modulation of oceanic processes (entrainment, mixing, Ekman pumping, lateral advection). Our {proportional_to}100 km resolution model suggests that internal oceanic variability (i.e. eddies) contributes substantially to intraseasonal variability at small-scale in the Somali upwelling region

  2. Processes of 30-90 days sea surface temperature variability in the northern Indian Ocean during boreal summer

    Science.gov (United States)

    Vialard, J.; Jayakumar, A.; Gnanaseelan, C.; Lengaigne, M.; Sengupta, D.; Goswami, B. N.

    2012-05-01

    During summer, the northern Indian Ocean exhibits significant atmospheric intraseasonal variability associated with active and break phases of the monsoon in the 30-90 days band. In this paper, we investigate mechanisms of the Sea Surface Temperature (SST) signature of this atmospheric variability, using a combination of observational datasets and Ocean General Circulation Model sensitivity experiments. In addition to the previously-reported intraseasonal SST signature in the Bay of Bengal, observations show clear SST signals in the Arabian Sea related to the active/break cycle of the monsoon. As the atmospheric intraseasonal oscillation moves northward, SST variations appear first at the southern tip of India (day 0), then in the Somali upwelling region (day 10), northern Bay of Bengal (day 19) and finally in the Oman upwelling region (day 23). The Bay of Bengal and Oman signals are most clearly associated with the monsoon active/break index, whereas the relationship with signals near Somali upwelling and the southern tip of India is weaker. In agreement with previous studies, we find that heat flux variations drive most of the intraseasonal SST variability in the Bay of Bengal, both in our model (regression coefficient, 0.9, against ~0.25 for wind stress) and in observations (0.8 regression coefficient); ~60% of the heat flux variation is due do shortwave radiation and ~40% due to latent heat flux. On the other hand, both observations and model results indicate a prominent role of dynamical oceanic processes in the Arabian Sea. Wind-stress variations force about 70-100% of SST intraseasonal variations in the Arabian Sea, through modulation of oceanic processes (entrainment, mixing, Ekman pumping, lateral advection). Our ~100 km resolution model suggests that internal oceanic variability (i.e. eddies) contributes substantially to intraseasonal variability at small-scale in the Somali upwelling region, but does not contribute to large-scale intraseasonal SST

  3. Application of the Unity Rockfall Model to Variable Surface Material Conditions

    Science.gov (United States)

    Sala, Zac; Hutchinson, D. Jean; Ondercin, Matthew

    2017-04-01

    Rockfall is a geological process that poses risks to the safe operation of transportation infrastructure in mountainous environments world wide. The Unity rockfall model was created as a tool for 3D rockfall simulation as part of the Railway Ground Hazards Research Program, studying the impact of geotechnical hazards affecting Canadian railways [1]. The Unity rockfall model demonstrates the applicability of 3D video game engines for the development of realistic simulations, leveraging high-resolution site data collected using remote sensing techniques. Currently work is being done to further calibrate the model as an engineering tool for decision support. Calibration datasets include high-resolution terrestrial LiDAR and helicopter photogrammetry data collected as part of an ongoing rockfall monitoring program along the Thompson River Valley in south-central British Columbia, Canada. Change detection techniques developed as part of the program have been used to construct a database of rockfall event history and to develop magnitude-frequency relationships for rockfalls in the area [2][3]. Data collected as part of a controlled rock-rolling field program in Christchurch, New Zealand [4] is also being utilized for model calibration. Data on block dynamics for the artificially triggered rockfalls were collected through the use of embedded motion sensors and a sixteen camera setup. These experiments provide detailed information on block kinematics, and capture each impact point of the rockfall with the slope, thus offering a valuable dataset for comparison with modelling results. The research reported here explores the ability of the game engine based modelling technique to simulate rockfall under the variable slope conditions present at each of the sites where calibration data was collected. This includes steep natural rock slopes, with debris-talus cover, as well as shallower slopes with soil cover and vegetation. The varying slope conditions in each environment

  4. Variable near-surface deformation along the Commerce segment of the Commerce geophysical lineament, southeast Missouri to southern Illinois, USA

    Science.gov (United States)

    Odum, J.K.; Stephenson, W.J.; Williams, R.A.

    2003-01-01

    Recent studies have demonstrated a plausible link between surface and near-surface tectonic features and the vertical projection of the Commerce geophysical lineament (CGL). The CGL is a 5- to 10-km-wide zone of basement magnetic and gravity anomalies traceable for more than 600 km, extending from Arkansas through southeast Missouri and southern Illinois and into Indiana. Twelve kilometers of high-resolution seismic reflection data, collected at four sites along a 175-km segment of the CGL projection, are interpreted to show varying amounts of deformation involving Tertiary and some Quaternary sediments. Some of the locally anomalous geomorphic features in the northern Mississippi embayment region (i.e., paleoliquefaction features, anomalous directional changes in stream channels, and areas of linear bluff escarpments) overlying the CGL can be correlated with specific faults and/or narrow zones of deformed (faulted and folded) strata that are imaged on high-resolution seismic reflection data. There is an observable change in near-surface deformation style and complexity progressing from the southwest to the northeast along the trace of the CGL. The seismic reflection data collaborate mapping evidence which suggests that this region has undergone a complex history of deformation, some of which is documented to be as young as Quaternary, during multiple episodes of reactivation under varying stress fields. This work, along with that of other studies presented in this volume, points to the existence of at least one major crustal feature outside the currently defined zone of seismic activity (New Madrid Seismic Zone) that should be considered as a significant potential source zone for seismogenic activity within the midcontinent region of the United States. ?? 2003 Elsevier B.V. All rights reserved.

  5. Estimating Spatial and Temporal Variability in Surface Kinematics of the Inylchek Glacier, Central Asia, using TerraSAR–X Data

    Directory of Open Access Journals (Sweden)

    Julia Neelmeijer

    2014-09-01

    Full Text Available We use 124 scenes of TerraSAR–X data that were acquired in 2009 and 2010 to analyse the spatial and temporal variability in surface kinematics of the debris-covered Inylchek Glacier, located in the Tien Shan mountain range in Central Asia. By applying the feature tracking method to the intensity information of the radar data and combining the results from the ascending and descending orbits, we derive the surface velocity field of the glaciated area. Analysing the seasonal variations over the upper part of the Southern Inylchek branch, we find a temperature-related increase in velocity from 25 cm/d up to 50 cm/d between spring and summer, with the peak occurring in June. Another prominent velocity peak is observable one month later in the lower part of the Southern Inylchek branch. This area shows generally little motion, with values of approximately 5–10 cm/d over the year, but yields surface kinematics of up to 25 cm/d during the peak period. Comparisons of the dates of annual glacial lake outburst floods (GLOFs of the proglacial Lake Merzbacher suggest that this lower part is directly influenced by the drainage, leading to the observed mini-surge, which has over twice the normal displacement rate. With regard to the GLOF and the related response of Inylchek Glacier, we conclude that X–band radar systems such as TerraSAR–X have a high potential for detecting and characterising small-scale glacial surface kinematic variations and should be considered for future inter-annual glacial monitoring tasks.

  6. Tropospheric ozone seasonal and long-term variability as seen by lidar and surface measurements at the JPL-Table Mountain Facility, California

    Directory of Open Access Journals (Sweden)

    M. J. Granados-Muñoz

    2016-07-01

    Full Text Available A combined surface and tropospheric ozone climatology and interannual variability study was performed for the first time using co-located ozone photometer measurements (2013–2015 and tropospheric ozone differential absorption lidar measurements (2000–2015 at the Jet Propulsion Laboratory Table Mountain Facility (TMF; elev. 2285 m, in California. The surface time series were investigated both in terms of seasonal and diurnal variability. The observed surface ozone is typical of high-elevation remote sites, with small amplitude of the seasonal and diurnal cycles, and high ozone values, compared to neighboring lower altitude stations representative of urban boundary layer conditions. The ozone mixing ratio ranges from 45 ppbv in the winter morning hours to 65 ppbv in the spring and summer afternoon hours. At the time of the lidar measurements (early night, the seasonal cycle observed at the surface is similar to that observed by lidar between 3.5 and 9 km. Above 9 km, the local tropopause height variation with time and season impacts significantly the ozone lidar observations. The frequent tropopause folds found in the vicinity of TMF (27 % of the time, mostly in winter and spring produce a dual-peak vertical structure in ozone within the fold layer, characterized by higher-than-average values in the bottom half of the fold (12–14 km, and lower-than-averaged values in the top half of the fold (14–18 km. This structure is consistent with the expected origin of the air parcels within the fold, i.e., mid-latitude stratospheric air folding down below the upper tropospheric sub-tropical air. The influence of the tropopause folds extends down to 5 km, increasing the ozone content in the troposphere. No significant signature of interannual variability could be observed on the 2000–2015 de-seasonalized lidar time series, with only a statistically non-significant positive anomaly during the years 2003–2007. Our trend analysis

  7. The Atlantic Multidecadal Variability in surface and deep ocean temperature and salinity fields from unperturbed climate simulations

    Science.gov (United States)

    Zanchettin, D.; Jungclaus, J. H.

    2013-12-01

    Large multidecadal fluctuations in basin-average sea-surface temperature (SST) are a known feature of observed, reconstructed and simulated variability in the North Atlantic Ocean. This phenomenon is often referred to as Multidecadal Atlantic Variability or AMV. Historical AMV fluctuations are associated with analog basin-scale changes in sea-surface salinity, so that warming corresponds to salinification and cooling to freshening [Polyakov et al., 2005]. The surface imprint of the AMV further corresponds to same-sign fluctuations in the shallow ocean and with opposite-sign fluctuations in the deep ocean for both temperature and salinity [Polyakov et al., 2005]. This out-of-phase behavior reflects the thermohaline overturning circulation shaping North Atlantic's low-frequency variability. Several processes contribute to the AMV, involving both ocean-atmosphere coupled processes and deep ocean circulation [e.g., Grossmann and Klotzbach, 2009]. In particular, recirculation in the North Atlantic subpolar gyre region of salinity anomalies from Arctic freshwater export may trigger multidecadal variability in the Atlantic meridional overturning circulation, and therefore may be part of the AMV [Jungclaus et al., 2005; Dima and Lohmann, 2007]. With this contribution, we aim to improve the physical interpretation of the AMV by investigating spatial and temporal patterns of temperature and salinity fields in the shallow and deep ocean. We focus on two unperturbed millennial-scale simulations performed with the Max Planck Institute Earth system model in its paleo (MPI-ESM-P) and low-resolution (MPI-ESM-LR) configurations, which provide reference control climates for assessments of pre-industrial and historical climate simulations. The two model configurations only differ for the presence, in MPI-ESM-LR, of an active module for dynamical vegetation. We use spatial-average indices and empirical orthogonal functions/principal components to track the horizontal and vertical

  8. Surface-Air Mercury Fluxes Across Western North America: A Synthesis of Spatial Trends and Controlling Variables.

    Science.gov (United States)

    Eckley, C.; Tate, M.; Lin, C. J.; Gustin, M. S.; Dent, S.; Eagles-Smith, C.; Lutz, M.; Wickland, K.; Wang, B.; Gray, J.; Edwards, G. C.; Krabbenhoft, D. P.; Smith, D. B.

    2016-12-01

    Mercury (Hg) emission and deposition can occur to and from soils and are an important component of the global atmospheric Hg budget. This presentation focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere.

  9. Investigating the spatio-temporal variability in groundwater and surface water interactions: a multi-technical approach

    Science.gov (United States)

    Unland, N. P.; Cartwright, I.; Andersen, M. S.; Rau, G. C.; Reed, J.; Gilfedder, B. S.; Atkinson, A. P.; Hofmann, H.

    2013-03-01

    The interaction between groundwater and surface water along the Tambo and Nicholson Rivers, southeast Australia, was investigated using 222Rn, Cl, differential flow gauging, head gradients, electrical conductivity (EC) and temperature profiling. Head gradients, temperature profiles, Cl concentrations and 222Rn activities all indicate higher groundwater fluxes to the Tambo River in areas of increased topographic variation where the potential to form large groundwater-surface water gradients is greater. Groundwater discharge to the Tambo River calculated by Cl mass balance was significantly lower (1.48 × 104 to 1.41 × 103 m3 day-1) than discharge estimated by 222Rn mass balance (5.35 × 105 to 9.56 × 103 m3 day-1) and differential flow gauging (5.41 × 105 to 6.30 × 103 m3 day-1). While groundwater sampling from the bank of the Tambo River was intended to account for the variability in groundwater chemistry associated with river-bank interaction, the spatial variability under which these interactions occurs remained unaccounted for, limiting the use of Cl as an effective tracer. Groundwater discharge to both the Tambo and Nicholson Rivers was the highest under high flow conditions in the days to weeks following significant rainfall, indicating that the rivers are well connected to a groundwater system that is responsive to rainfall. Groundwater constituted the lowest proportion of river discharge during times of increased rainfall that followed dry periods, while groundwater constituted the highest proportion of river discharge under baseflow conditions (21.4% of the Tambo in April 2010 and 18.9% of the Nicholson in September 2010).

  10. Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

    Science.gov (United States)

    Eckley, Chris S.; Tate, Michael T.; Lin, Che-Jen; Gustin, Mae S.; Dent, Stephen; Eagles-Smith, Collin A.; Lutz, Michelle A; Wickland, Kimberly; Wang, Bronwen; Gray, John E.; Edwards, Grant; Krabbenhoft, David P.; Smith, David

    2016-01-01

    Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere.

  11. Variability and Predictability of West African Droughts. A Review in the Role of Sea Surface Temperature Anomalies

    Science.gov (United States)

    Rodriguez-Fonseca, Belen; Mohino, Elsa; Mechoso, Carlos R.; Caminade, Cyril; Biasutti, Michela; Gaetani, Marco; Garcia-Serrano, J.; Vizy, Edward K.; Cook, Kerry; Xue, Yongkang; hide

    2015-01-01

    The Sahel experienced a severe drought during the 1970s and 1980s after wet periods in the 1950s and 1960s. Although rainfall partially recovered since the 1990s, the drought had devastating impacts on society. Most studies agree that this dry period resulted primarily from remote effects of sea surface temperature (SST) anomalies amplified by local land surface-atmosphere interactions. This paper reviews advances made during the last decade to better understand the impact of global SST variability on West African rainfall at interannual to decadal time scales. At interannual time scales, a warming of the equatorial Atlantic and Pacific/Indian Oceans results in rainfall reduction over the Sahel, and positive SST anomalies over the Mediterranean Sea tend to be associated with increased rainfall. At decadal time scales, warming over the tropics leads to drought over the Sahel, whereas warming over the North Atlantic promotes increased rainfall. Prediction systems have evolved from seasonal to decadal forecasting. The agreement among future projections has improved from CMIP3 to CMIP5, with a general tendency for slightly wetter conditions over the central part of the Sahel, drier conditions over the western part, and a delay in the monsoon onset. The role of the Indian Ocean, the stationarity of teleconnections, the determination of the leader ocean basin in driving decadal variability, the anthropogenic role, the reduction of the model rainfall spread, and the improvement of some model components are among the most important remaining questions that continue to be the focus of current international projects.

  12. Seasonal and interannual variability of surface CDOM in the South China Sea associated with El Niño

    Science.gov (United States)

    Ma, Jinfeng; Zhan, Haigang; Du, Yan

    2011-04-01

    Satellite imagery of SeaWiFS from October 1997 to November 2007 is used to investigate the dominant seasonal and interannual variations of the surface light absorption due to Colored Dissolved Organic Materials (CDOM) in the South China Sea (SCS). Results show that the spatial distribution of CDOM mimics the major features of the SCS basin-scale circulation. High values of CDOM are found in upwelling regions like southeast of Vietnam in summer and northwest of Luzon in winter. At a basin scale, CDOM is high in winter when upwelling is strong, solar shortwave radiation and stratification weak, and vertical mixing intense. Opposite conditions exist in spring and summer. Interannual variability of the basin-wide CDOM is characterized by abnormal troughs during the El Niño events. A strong relationship exists between the time series of the first EOF mode (for both winter and summer) and Niño 3.4 Index. Associations of these events with climatic and hydrographic properties (i.e. wind forcing, solar shortwave radiation, Ekman pumping, vertical mixing, sea surface height and temperature) are discussed.

  13. Internal variability in a 1000-yr control simulation with the coupled climate model ECHO-G - I. Near-surface temperature, precipitation and mean sea level pressure.

    Energy Technology Data Exchange (ETDEWEB)

    Min, Seung-Ki; Hense, Andreas [Univ. of Bonn (Germany). Meteorological Inst.; Legutke, Stephanie [Max Planck Inst. for Meteorology, Hamburg (Germany); Kwon, Won-Tae [Meteorological Research Inst., Seoul (Korea, Republic of)

    2005-08-01

    The internal variability in a 1000-yr control simulation with the coupled atmosphere/ocean global climate model ECHO-G is analysed using near-surface temperature, precipitation and mean sea level pressure variables, and is compared with observations and other coupled climate model simulations. ECHO-G requires annual mean flux adjustments for heat and freshwater in order to simulate no significant climate drift for 1000 yr, but no flux adjustments for momentum. The ECHO-G control run captures well most aspects of the observed seasonal and annual climatology and of the interannual to decadal variability of the three variables. Model biases are very close to those in ECHAM4 (atmospheric component of ECHO-G) stand-alone integrations with prescribed observed sea surface temperature. A trend comparison between observed and modelled near-surface temperatures shows that the observed near-surface global warming is larger than internal variability produced by ECHO-G, supporting previous studies. The simulated global mean near-surface temperatures, however, show a 2-yr spectral peak which is linked with a strong biennial bias of energy in the El Nino Southern Oscillation signal. Consequently, the interannual variability (39 yr) is underestimated.

  14. Free water surface constructed wetlands limit the dissemination of extended-spectrum beta-lactamase producing Escherichia coli in the natural environment.

    Science.gov (United States)

    Vivant, Anne-Laure; Boutin, Catherine; Prost-Boucle, Stéphanie; Papias, Sandrine; Hartmann, Alain; Depret, Géraldine; Ziebal, Christine; Le Roux, Sophie; Pourcher, Anne-Marie

    2016-11-01

    The fates of Escherichia coli and extended-spectrum beta-lactamase-producing E. coli (ESBL E. coli) were studied over a period of one year in a free water surface constructed wetland (FWS CW) with a succession of open water zones and vegetation ponds (Typha or Phragmites), that received the effluent from a wastewater treatment plant. ESBL E. coli were detected and isolated from all sampling areas of the FWS CW throughout the study period. They represented 1‰ of the total E. coli population regardless of the origin of samples. Two main factors affected the log removal of E. coli and of ESBL E. coli: the season and the presence of vegetation. Between the inlet and the outlet of the FWS CW, the log removal of E. coli ranged from 1.5 in the warmer season (summer and fall) to 3.0 in the colder season (winter and spring). The concentrations of E. coli decreased significantly in the vegetated areas during the colder season, but increased in the warmer season, suggesting an effect of the plant growth stage on the survival of E. coli. Among the 369 ESBL E. coli isolates collected during our study, 84% harbored the CTX-M-ESBL type and 55.3% carried bla genes on plasmid DNA. Furthermore, 93% of the ESBL E. coli isolates were multidrug resistant but the proportion of resistant strains did not change significantly along the FWS CW. ESBL E. coli were characterized by MLST analysis using the 7 genes based Achtman Scheme. ESBL E. coli isolated from water, sediments, roots and feces of myocastors collected in the FWS CW and in the recipient river were genotypically related, suggesting persistence and circulation of the ESBL producing E. coli throughout the FWS CW and in the receiving river. Overall, these observations show that FWS CW could be an efficient treatment for ESBL E. coli disinfection of wastewater and could limit their dissemination in the aquatic environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Extended spider cognition.

    Science.gov (United States)

    Japyassú, Hilton F; Laland, Kevin N

    2017-05-01

    There is a tension between the conception of cognition as a central nervous system (CNS) process and a view of cognition as extending towards the body or the contiguous environment. The centralised conception requires large or complex nervous systems to cope with complex environments. Conversely, the extended conception involves the outsourcing of information processing to the body or environment, thus making fewer demands on the processing power of the CNS. The evolution of extended cognition should be particularly favoured among small, generalist predators such as spiders, and here, we review the literature to evaluate the fit of empirical data with these contrasting models of cognition. Spiders do not seem to be cognitively limited, displaying a large diversity of learning processes, from habituation to contextual learning, including a sense of numerosity. To tease apart the central from the extended cognition, we apply the mutual manipulability criterion, testing the existence of reciprocal causal links between the putative elements of the system. We conclude that the web threads and configurations are integral parts of the cognitive systems. The extension of cognition to the web helps to explain some puzzling features of spider behaviour and seems to promote evolvability within the group, enhancing innovation through cognitive connectivity to variable habitat features. Graded changes in relative brain size could also be explained by outsourcing information processing to environmental features. More generally, niche-constructed structures emerge as prime candidates for extending animal cognition, generating the selective pressures that help to shape the evolving cognitive system.

  16. North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation

    Directory of Open Access Journals (Sweden)

    I. Medhaug

    2011-06-01

    Full Text Available Output from a total of 24 state-of-the-art Atmosphere-Ocean General Circulation Models is analyzed. The models were integrated with observed forcing for the period 1850–2000 as part of the Intergovernmental Panel on Climate Change (IPCC Fourth Assessment Report. All models show enhanced variability at multi-decadal time scales in the North Atlantic sector similar to the observations, but with a large intermodel spread in amplitudes and frequencies for both the Atlantic Multidecadal Oscillation (AMO and the Atlantic Meridional Overturning Circulation (AMOC. The models, in general, are able to reproduce the observed geographical patterns of warm and cold episodes, but not the phasing such as the early warming (1930s–1950s and the following colder period (1960s–1980s. This indicates that the observed 20th century extreme in temperatures are due to primarily a fortuitous phasing of intrinsic climate variability and not dominated by external forcing. Most models show a realistic structure in the overturning circulation, where more than half of the available models have a mean overturning transport within the observed estimated range of 13–24 Sverdrup. Associated with a stronger than normal AMOC, the surface temperature is increased and the sea ice extent slightly reduced in the North Atlantic. Individual models show potential for decadal prediction based on the relationship between the AMO and AMOC, but the models strongly disagree both in phasing and strength of the covariability. This makes it difficult to identify common mechanisms and to assess the applicability for predictions.

  17. Are Simulated and Observed Twentieth Century Tropical Pacific Sea Surface Temperature Trends Significant Relative to Internal Variability?

    Science.gov (United States)

    Coats, S.; Karnauskas, K. B.

    2017-10-01

    Historical trends in the tropical Pacific zonal sea surface temperature gradient (SST gradient) are analyzed herein using 41 climate models (83 simulations) and 5 observational data sets. A linear inverse model is trained on each simulation and observational data set to assess if trends in the SST gradient are significant relative to the stationary statistics of internal variability, as would suggest an important role for external forcings such as anthropogenic greenhouse gasses. None of the 83 simulations have a positive trend in the SST gradient, a strengthening of the climatological SST gradient with more warming in the western than eastern tropical Pacific, as large as the mean trend across the five observational data sets. If the observed trends are anthropogenically forced, this discrepancy suggests that state-of-the-art climate models are not capturing the observed response of the tropical Pacific to anthropogenic forcing, with serious implications for confidence in future climate projections. There are caveats to this interpretation, however, as some climate models have a significant strengthening of the SST gradient between 1900 and 2013 Common Era, though smaller in magnitude than the observational data sets, and the strengthening in three out of five observational data sets is insignificant. When combined with observational uncertainties and the possibility of centennial time scale internal variability not sampled by the linear inverse model, this suggests that confident validation of anthropogenic SST gradient trends in climate models will require further emergence of anthropogenic trends. Regardless, the differences in SST gradient trends between climate models and observational data sets are concerning and motivate the need for process-level validation of the atmosphere-ocean dynamics relevant to climate change in the tropical Pacific.

  18. Surface water / groundwater interactions and their spatial variability, an example from the Avon River, South-East Australia

    Science.gov (United States)

    Hofmann, Harald; Cartwright, Ian; Gilfedder, Benjamin

    2013-04-01

    Understanding the interaction between river water and regional groundwater has significant importance for water management and resource allocation. The dynamics of groundwater/surface water interactions also have implications for ecosystems, pollutant transport, and the quality and quantity of water supply for domestic, agriculture and recreational purposes. After general assumptions and for management purposes rivers are classified in loosing or gaining rivers. However, many streams alternate between gaining and loosing conditions on a range of temporal and spatial scales due to factors including: 1) river water levels in relation to groundwater head; 2) the relative response of the groundwater and river system to rainfall; 3) heterogeneities in alluvial sediments that can lead to alternation of areas of exfiltration and infiltration along a river stretch; and 4) differences in near river reservoirs, such parafluvial flow and bank storage. Spatial variability of groundwater discharge to rivers is rarely accounted for as it is assumed that groundwater discharge is constant over river stretches and only changes with the seasonal river water levels. Riverbank storage and parafluvial flow are generally not taken in consideration. Bank storage has short-term cycles and can contribute significantly to the total discharge, especially after flood events. In this study we used hydrogeochemistry to constrain spatial and temporal differences in gaining and loosing conditions in rivers and investigate potential sources. Environmental tracers, such as major ion chemistry, stables isotopes and Radon are useful tools to characterise these sources. Surface water and ground water samples were taken in the Avon River in the Gippsland Basin, Southwest Australia. Increasing TDS along the flow path from 70 to 250 mg/l, show that the Avon is a net gaining stream. The radon concentration along the river is variable and does not show a general increase downstream, but isolated peaks in

  19. Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

    Energy Technology Data Exchange (ETDEWEB)

    Eckley, Chris S., E-mail: eckley.chris@epa.gov [US Environmental Protection Agency, Region-10, Seattle, WA 98101 (United States); Tate, Mike T. [US Geological Survey, Middleton, WI 53562 (United States); Lin, Che-Jen [Center for Advances on Water and Air quality, Lamar University, Beaumont, TX 77710 (United States); Gustin, Mae [Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV 89557 (United States); Dent, Stephen [CDM Smith, Portland, OR 97205 (United States); Eagles-Smith, Collin [US Geological Survey, Corvallis, OR 97331 (United States); Lutz, Michelle A. [US Geological Survey, Middleton, WI 53562 (United States); Wickland, Kimberly P. [US Geological Survey Boulder, CO 80303 (United States); Wang, Bronwen [US Geological Survey, Anchorage, AK 99508 (United States); Gray, John E. [US Geological Survey, Denver, CO 80225 (United States); Edwards, Grant C. [Department of Environment and Geography, Macquarie University, North Ryde, NSW 2109 (Australia); Krabbenhoft, Dave P. [US Geological Survey, Middleton, WI 53562 (United States); Smith, David B. [US Geological Survey, Denver, CO 80225 (United States)

    2016-10-15

    Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere. - Highlights: • Soil-air Hg fluxes are an important component of the

  20. South Asian summer monsoon variability during the last ˜54 kyrs inferred from surface water salinity and river runoff proxies

    Science.gov (United States)

    Gebregiorgis, D.; Hathorne, E. C.; Sijinkumar, A. V.; Nath, B. Nagender; Nürnberg, D.; Frank, M.

    2016-04-01

    The past variability of the South Asian Monsoon is mostly known from records of wind strength over the Arabian Sea while high-resolution paleorecords from regions of strong monsoon precipitation are still lacking. Here, we present records of past monsoon variability obtained from sediment core SK 168/GC-1, which was collected at the Alcock Seamount complex in the Andaman Sea. We utilize the ecological habitats of different planktic foraminiferal species to reconstruct freshwater-induced stratification based on paired Mg/Ca and δ18O analyses and to estimate seawater δ18O (δ18Osw). The difference between surface and thermocline temperatures (ΔT) and δ18Osw (Δδ18Osw) is used to investigate changes in upper ocean stratification. Additionally, Ba/Ca in G. sacculifer tests is used as a direct proxy for riverine runoff and sea surface salinity (SSS) changes related to monsoon precipitation on land. Our Δδ18Osw time series reveals that upper ocean salinity stratification did not change significantly throughout the last glacial suggesting little influence of NH insolation changes. The strongest increase in temperature gradients between the mixed layer and the thermocline is recorded for the mid-Holocene and indicate the presence of a significantly shallower thermocline. In line with previous work, the δ18Osw and Ba/Ca records demonstrate that monsoon climate during the LGM was characterized by a significantly weaker southwest monsoon circulation and strongly reduced runoff. Based on our data the South Asian Summer Monsoon (SAM) over the Irrawaddyy strengthened gradually after the LGM beginning at ∼18 ka. This is some 3 kyrs before an increase of the Ba/Ca record from the Arabian Sea and indicates that South Asian Monsoon climate dynamics are more complex than the simple N-S displacement of the ITCZ as generally described for other regions. Minimum δ18Osw values recorded during the mid-Holocene are in phase with Ba/Ca marking a stronger monsoon precipitation

  1. Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

    International Nuclear Information System (INIS)

    Eckley, Chris S.; Tate, Mike T.; Lin, Che-Jen; Gustin, Mae; Dent, Stephen; Eagles-Smith, Collin; Lutz, Michelle A.; Wickland, Kimberly P.; Wang, Bronwen; Gray, John E.; Edwards, Grant C.; Krabbenhoft, Dave P.; Smith, David B.

    2016-01-01

    Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere. - Highlights: • Soil-air Hg fluxes are an important component of the

  2. Near-surface wind variability over the broader Adriatic region: insights from an ensemble of regional climate models

    Science.gov (United States)

    Belušić, Andreina; Prtenjak, Maja Telišman; Güttler, Ivan; Ban, Nikolina; Leutwyler, David; Schär, Christoph

    2018-06-01

    Over the past few decades the horizontal resolution of regional climate models (RCMs) has steadily increased, leading to a better representation of small-scale topographic features and more details in simulating dynamical aspects, especially in coastal regions and over complex terrain. Due to its complex terrain, the broader Adriatic region represents a major challenge to state-of-the-art RCMs in simulating local wind systems realistically. The objective of this study is to identify the added value in near-surface wind due to the refined grid spacing of RCMs. For this purpose, we use a multi-model ensemble composed of CORDEX regional climate simulations at 0.11° and 0.44° grid spacing, forced by the ERA-Interim reanalysis, a COSMO convection-parameterizing simulation at 0.11° and a COSMO convection-resolving simulation at 0.02° grid spacing. Surface station observations from this region and satellite QuikSCAT data over the Adriatic Sea have been compared against daily output obtained from the available simulations. Both day-to-day wind and its frequency distribution are examined. The results indicate that the 0.44° RCMs rarely outperform ERA-Interim reanalysis, while the performance of the high-resolution simulations surpasses that of ERA-Interim. We also disclose that refining the grid spacing to a few km is needed to properly capture the small-scale wind systems. Finally, we show that the simulations frequently yield the accurate angle of local wind regimes, such as for the Bora flow, but overestimate the associated wind magnitude. Finally, spectral analysis shows good agreement between measurements and simulations, indicating the correct temporal variability of the wind speed.

  3. Linking land use changes to surface water quality variability in Lake Victoria: some insights from remote sensing

    Science.gov (United States)

    Mugo, R. M.; Limaye, A. S.; Nyaga, J. W.; Farah, H.; Wahome, A.; Flores, A.

    2016-12-01

    The water quality of inland lakes is largely influenced by land use and land cover changes within the lake's catchment. In Africa, some of the major land use changes are driven by a number of factors, which include urbanization, intensification of agricultural practices, unsustainable farm management practices, deforestation, land fragmentation and degradation. Often, the impacts of these factors are observable on changes in the land cover, and eventually in the hydrological systems. When the natural vegetation cover is reduced or changed, the surface water flow patterns, water and nutrient retention capacities are also changed. This can lead to high nutrient inputs into lakes, leading to eutrophication, siltation and infestation of floating aquatic vegetation. To assess the relationship between land use and land cover changes in part of the Lake Victoria Basin, a series of land cover maps were derived from Landsat imagery. Changes in land cover were identified through change maps and statistics. Further, the surface water chlorophyll-a concentration and turbidity were derived from MODIS-Aqua data for Lake Victoria. Chlrophyll-a and turbidity are good proxy indicators of nutrient inputs and siltation respectively. The trends in chlorophyll-a and turbidity concentrations were analyzed and compared to the land cover changes over time. Certain land cover changes related to agriculture and urban development were clearly identifiable. While these changes might not be solely responsible for variability in chlrophyll-a and turbidity concentrations in the lake, they are potentially contributing factors to this problem. This work illustrates the importance of addressing watershed degradation while seeking to solve water quality related problems.

  4. Study on the essential variables for pipe outer surface irradiated laser stress improvement process (L-SIP). Development of pipe outer surface irradiated laser stress improvement process (L-SIP)

    International Nuclear Information System (INIS)

    Ohta, Takahiro; Kamo, Kazuhiko; Muroya, Itaru; Asada, Seiji; Nakamura, Yasuo

    2009-01-01

    The new process called L-SIP (outer surface irradiated Laser Stress Improvement Process) is developed to improve the tensile residual stress of the inner surface near the butt welded joints of pipes in the compression stress. The temperature gradient occurs in the thickness of pipes in heating the outer surface rapidly by laser beam. By the thermal expansion difference between the inner surface and the outer surface, the compression stress occurs near the inner surface of pipes. In this paper, the essential variables for L-SIP is studied by experimental and FEM analysis. The range of the essential variables for L-SIP, which are defined by thermo-elastic FEM analysis, are Tmax=550 - 650degC, L Q /√rh ≥ 3, W Q /√rh ≥ 1.7, and, 0.04 ≤ F 0 ≤ 0.10 where Tmax is maximum temperature on the monitor point of the outer surface, F 0 is k x τ 0 /h 2 , k is thermal diffusivity coefficient, τ 0 is the temperature rise time from 100degC to maximum temperature on the monitor point of the outer surface, W Q is τ 0 x v, υ is moving velocity, L Q is the uniform temperature length in the axial direction, h is thickness of the pipe, and r is average radius of the pipe. It is showed by thermo-elastic-plastic FEM analysis that the residual stresses near the inner surface of pipes are improved in 4 different size pipes under the same essential variables. L-SIP is actually applied to welding joints of 4B x Sch160 and 2B x Sch80 SUS304 type stainless steel pipes within the defined range of the essential variables. The measured welding residual stresses on the inner surface near the welding joints are tensile. The residual stresses on the inner surface change to compression in all joints by L-SIP. (author)

  5. Variability of cold season surface air temperature over northeastern China and its linkage with large-scale atmospheric circulations

    Science.gov (United States)

    Zhuang, Yuanhuang; Zhang, Jingyong; Wang, Lin

    2018-05-01

    Cold temperature anomalies and extremes have profound effects on the society, the economy, and the environment of northeastern China (NEC). In this study, we define the cold season as the months from October to April, and investigate the variability of cold season surface air temperature (CSAT) over NEC and its relationships with large-scale atmospheric circulation patterns for the period 1981-2014. The empirical orthogonal function (EOF) analysis shows that the first EOF mode of the CSAT over NEC is characterized by a homogeneous structure that describes 92.2% of the total variance. The regionally averaged CSAT over NEC is closely linked with the Arctic Oscillation ( r = 0.62, 99% confidence level) and also has a statistically significant relation with the Polar/Eurasian pattern in the cold season. The positive phases of the Arctic Oscillation and the Polar/Eurasian pattern tend to result in a positive geopotential height anomaly over NEC and a weakened East Asian winter monsoon, which subsequently increase the CSAT over NEC by enhancing the downward solar radiation, strengthening the subsidence warming and warm air advection. Conversely, the negative phases of these two climate indices result in opposite regional atmospheric circulation anomalies and decrease the CSAT over NEC.

  6. Independent Subspace Analysis of the Sea Surface Temperature Variability: Non-Gaussian Sources and Sensitivity to Sampling and Dimensionality

    Directory of Open Access Journals (Sweden)

    Carlos A. L. Pires

    2017-01-01

    Full Text Available We propose an expansion of multivariate time-series data into maximally independent source subspaces. The search is made among rotations of prewhitened data which maximize non-Gaussianity of candidate sources. We use a tensorial invariant approximation of the multivariate negentropy in terms of a linear combination of squared coskewness and cokurtosis. By solving a high-order singular value decomposition problem, we extract the axes associated with most non-Gaussianity. Moreover, an estimate of the Gaussian subspace is provided by the trailing singular vectors. The independent subspaces are obtained through the search of “quasi-independent” components within the estimated non-Gaussian subspace, followed by the identification of groups with significant joint negentropies. Sources result essentially from the coherency of extremes of the data components. The method is then applied to the global sea surface temperature anomalies, equatorward of 65°, after being tested with non-Gaussian surrogates consistent with the data anomalies. The main emerging independent components and subspaces, supposedly generated by independent forcing, include different variability modes, namely, The East-Pacific, the Central Pacific, and the Atlantic Niños, the Atlantic Multidecadal Oscillation, along with the subtropical dipoles in the Indian, South Pacific, and South-Atlantic oceans. Benefits and usefulness of independent subspaces are then discussed.

  7. Dental microwear variability on buccal tooth enamel surfaces of extant Catarrhini and the Miocene fossil Dryopithecus laietanus (Hominoidea).

    Science.gov (United States)

    Galbany, J; Moyà-Solà, S; Pérez-Pérez, A

    2005-01-01

    Analyses of buccal tooth microwear have been used to trace dietary habits of modern hunter-gatherer populations. In these populations, the average density and length of striations on the buccal surfaces of teeth are significantly cor-related with the abrasive potential of food items consumed. In non-human pri-mates, tooth microwear patterns on both occlusal and buccal wear facets have been thoroughly studied and the results applied to the characterization of dietary habits of fossil species. In this paper, we present inter- and intra-specific buccal microwear variability analyses in extant Cercopithecoidea (Cercopithecus mitis, C. neglectus, Chlorocebus aethiops, Colobus spp., Papio anubis) and Hominoidea (Gorilla gorilla, Pan troglodytes, Pongo pygmaeus). The results are tentatively compared to buccal microwear patterns of the Miocene fossils Dryopithecus and Oreopithecus. Significant differences in striation density and length are found among the fossil taxa studied and the extant primates, suggesting that buccal microwear can be used to identify dietary differences among taxa. The Dryopithecus buccal microwear pattern most closely resembles that of abrasive, tough plant foods consumers, such as the gorilla, in contrast to stud-ies of dental morphology that suggest a softer, frugivorous diet. Results for Oreopithecus were equivocal, but suggest a more abrasive diet than that previously thought. (c) 2005 S. Karger AG, Basel.

  8. Sea surface temperature variability in the North Western Mediterranean Sea (Gulf of Lion) during the Common Era

    Science.gov (United States)

    Sicre, Marie-Alexandrine; Jalali, Bassem; Martrat, Belen; Schmidt, Sabine; Bassetti, Maria-Angela; Kallel, Nejib

    2016-12-01

    This study investigates the multidecadal-scale variability of sea surface temperatures (SSTs) in the convection region of the Gulf of Lion (NW Mediterranean Sea) over the full past 2000 yr (Common Era) using alkenone biomarkers. Our data show colder SSTs by 1.7 °C over most of the first millennium (200-800 AD) and by 1.3 °C during the Little Ice Age (LIA; 1400-1850 AD) than the 20th century mean (17.9 °C). Although on average warmer, those of the Medieval Climate Anomaly (MCA) (1000-1200 AD) were lower by 1 °C. We found a mean SST warming of 2 °C/100 yr over the last century in close agreement with the 0.22 and 0.26 °C/decade values calculated for the western Mediterranean Sea from in situ and satellite data, respectively. Our results also reveal strongly fluctuating SSTs characterized by cold extremes followed by abrupt warming during the LIA. We suggest that the coldest decades of the LIA were likely caused by prevailing negative EA states and associated anticyclone blocking over the North Atlantic resulting in cold continental northeasterly winds to blow over Western Europe and the Mediterranean region.

  9. Extended Irreversible Thermodynamics

    CERN Document Server

    Jou, David

    2010-01-01

    This is the 4th edition of the highly acclaimed monograph on Extended Irreversible Thermodynamics, a theory that goes beyond the classical theory of irreversible processes. In contrast to the classical approach, the basic variables describing the system are complemented by non-equilibrium quantities. The claims made for extended thermodynamics are confirmed by the kinetic theory of gases and statistical mechanics. The book covers a wide spectrum of applications, and also contains a thorough discussion of the foundations and the scope of the current theories on non-equilibrium thermodynamics. For this new edition, the authors critically revised existing material while taking into account the most recent developments in fast moving fields such as heat transport in micro- and nanosystems or fast solidification fronts in materials sciences. Several fundamental chapters have been revisited emphasizing physics and applications over mathematical derivations. Also, fundamental questions on the definition of non-equil...

  10. Variability and trends of downward surface global solar radiation over the Iberian Peninsula based on ERA-40 reanalysis

    KAUST Repository

    Perdigão, João Carlos

    2016-01-26

    © 2016 Royal Meteorological Society. A climate study of the incidence of downward surface global solar radiation (SSRD) in the Iberian Peninsula (IP) based primarily on ERA-40 reanalysis is presented. NCEP/NCAR reanalysis and ground-based records from several Portuguese and Spanish stations have been also considered. The results show that reanalysis can capture a similar inter-annual variability as compared to ground-based observations, especially on a monthly basis, even though annual ERA-40 (NCEP/NCAR) values tend to underestimate (overestimate) the observations with a mean relative difference of around 20Wm-2 (40Wm-2). On the other hand, ground-based measurements in Portuguese stations during the period 1964-1989 show a tendency to decrease until the mid-1970s followed by an increase up to the end of the study period, in line with the dimming/brightening phenomenon reported in the literature. Nevertheless, there are different temporal behaviours as a greater increase since the 1970s is observed in the south and less industrialized regions. Similarly, the ERA-40 reanalysis shows a noticeable decrease until the early 1970s followed by a slight increase up to the end of the 1990s, suggesting a dimming/brightening transition around the early 1970s, earlier in the south and centre and later in the north of the IP. Although there are slight differences in the magnitude of the trends as well as the turning year of the dimming/brightening periods, the decadal changes of ERA-40 fairly agree with the ground-based observations in Portugal and Spain, in contrast to most of the literature for other regions of the world, and is used in the climatology of the SSRD in the study area. NCEP/NCAR reanalysis does not capture the decadal variations of SSRD in the IP. The results show that part of the decadal variability of the global radiation in the IP is related to changes in cloud cover (represented in ERA-40).

  11. Variability and trends of downward surface global solar radiation over the Iberian Peninsula based on ERA-40 reanalysis

    KAUST Repository

    Perdigã o, Joã o Carlos; Salgado, Rui; Costa, Maria Joã o; Dasari, Hari Prasad; Sanchez-Lorenzo, Arturo

    2016-01-01

    © 2016 Royal Meteorological Society. A climate study of the incidence of downward surface global solar radiation (SSRD) in the Iberian Peninsula (IP) based primarily on ERA-40 reanalysis is presented. NCEP/NCAR reanalysis and ground-based records from several Portuguese and Spanish stations have been also considered. The results show that reanalysis can capture a similar inter-annual variability as compared to ground-based observations, especially on a monthly basis, even though annual ERA-40 (NCEP/NCAR) values tend to underestimate (overestimate) the observations with a mean relative difference of around 20Wm-2 (40Wm-2). On the other hand, ground-based measurements in Portuguese stations during the period 1964-1989 show a tendency to decrease until the mid-1970s followed by an increase up to the end of the study period, in line with the dimming/brightening phenomenon reported in the literature. Nevertheless, there are different temporal behaviours as a greater increase since the 1970s is observed in the south and less industrialized regions. Similarly, the ERA-40 reanalysis shows a noticeable decrease until the early 1970s followed by a slight increase up to the end of the 1990s, suggesting a dimming/brightening transition around the early 1970s, earlier in the south and centre and later in the north of the IP. Although there are slight differences in the magnitude of the trends as well as the turning year of the dimming/brightening periods, the decadal changes of ERA-40 fairly agree with the ground-based observations in Portugal and Spain, in contrast to most of the literature for other regions of the world, and is used in the climatology of the SSRD in the study area. NCEP/NCAR reanalysis does not capture the decadal variations of SSRD in the IP. The results show that part of the decadal variability of the global radiation in the IP is related to changes in cloud cover (represented in ERA-40).

  12. Correlation between sea surface temperature and wind speed in Greenland Sea and their relationships with NAO variability

    Directory of Open Access Journals (Sweden)

    Bo Qu

    2012-09-01

    Full Text Available The North Atlantic Oscillation (NAO is one of the major causes of many recent changes in the Arctic Ocean. Generally, it is related to wind speed, sea surface temperature (SST, and sea ice cover. In this study, we analyzed the distributions of and correlations between SST, wind speed, NAO, and sea ice cover from 2003 to 2009 in the Greenland Sea at 10°W to 10°E, 65°N to 80°N. SST reached its peak in July, while wind speed reached its minimum in July. Seasonal variability of SST and wind speed was different for different regions. SST and wind speed mainly had negative correlations. Detailed correlation research was focused on the 75°N to 80°N band. Regression analysis shows that in this band, the variation of SST lagged three months behind that of wind speed. Ice cover and NAO had a positive correlation, and the correlation coefficient between ice cover and NAO in the year 2007 was 0.61. SST and NAO also had a positive correlation, and SST influenced NAO one month in advance. The correlation coefficients between SST and NAO reached 0.944 for the year 2005, 0.7 for the year 2008, and 0.74 for the year 2009 after shifting SST one month later. NAO also had a positive correlation with wind speed, and it also influenced wind speed one month in advance. The correlation coefficients between NAO and wind speed reached 0.783, 0.813, and 0.818 for the years 2004, 2005, and 2008, respectively, after shifting wind speed one month earlier.

  13. Variability of the Tropical Ocean Surface Temperatures at Decadal-Multidecadal Timescales. Part I: The Atlantic Ocean.

    Science.gov (United States)

    Mehta, Vikram M.

    1998-09-01

    Gridded time series from the Global Ocean Surface Temperature Atlas were analyzed with a variety of techniques to identify spatial structures and oscillation periods of the tropical Atlantic sea surface temperature (SST) variations at decadal timescales, and to develop physical interpretations of statistical patterns of decadal SST variations. Each time series was 110 yr (1882-1991) long. The tropical Atlantic SST variations were compared with decadal variations in a 74-yr-long (1912-85) north Nordeste Brazil rainfall time series and a 106-yr-long (1886-1991) tropical Atlantic cyclone activity index time series. The tropical Atlantic SST variations were also compared with decadal variations in the extratropical Atlantic SST.Multiyear to multidecadal variations in the cross-equatorial dipole pattern identified as a dominant empirical pattern of the tropical Atlantic SST variations in earlier and present studies are shown to be variations in the approximately north-south gradient of SST anomalies. It is also shown that there was no dynamical-thermodynamical, dipole mode of SST variations during the analysis period. There was a distinct decadal timescale (12-13 yr) of SST variations in the tropical South Atlantic, whereas no distinct decadal timescale was found in the tropical North Atlantic SST variations. Approximately 80% of the coherent decadal variance in the cross-equatorial SST gradient was `explained' by coherent decadal oscillations in the tropical South Atlantic SSTs. There were three, possibly physical, modes of decadal variations in the tropical Atlantic SSTs during the analysis period. In the more energetic mode of the North Atlantic decadal SST variations, anomalies traveled into the tropical North Atlantic from the extratropical North Atlantic along the eastern boundary of the basin. The anomalies strengthened and resided in the tropical North Atlantic for several years, then frequently traveled northward into the mid-high-latitude North Atlantic along

  14. Determination of aquifer roof extending under the sea from variable-density flow modelling of groundwater response to tidal loading: case study of the Jahe River Basin, Shandong Province, China

    Science.gov (United States)

    Cheng, Jianmei; Chen, Chongxi; Ji, Menrui

    The main task of studies on salt-water intrusion into coastal confined aquifers is to predict the position of the fresh- salt-water interface, which can be determined from the length of the aquifer roof extending under the sea. Records of groundwater level affected by tides can be used to infer hydrological conditions and determine hydraulic parameters of an aquifer extending under the sea. In this paper, a three-dimensional, variable-density groundwater flow model has been developed to determine the equivalent roof length of an aquifer extending under the sea from the tidal-effected data of groundwater level in the Jahe River Basin, Shandong Province, China. The seaward boundary is obtained by converging hydraulic head fluctuations observed in drill holes with calculated values, and the aquifer parameters in the extending zone are estimated. The impacts of aquifer roof length and aquifer parameters on the fluctuation of tidal groundwater are studied. It is concluded that the length of the aquifer roof extending under the sea should correspond with certain aquifer parameters in the extrapolation zone. Therefore, the seaward boundary determined from tidal-effect information is the equivalent boundary in hydrodynamic characteristics rather than the true boundary of the confined aquifer Les sujets principaux des études d'instrusion saline dans les aquifères confinés en zone côtière sont la prédiction de la position de l'interface entre l'eau salée et l'eau fraîche, qui peut être déterminée à partir de l'extention du toit de l'aquifère sous la mer. Les enregistrements des niveaux des eaux souterraines influencés par les marées peuvent être utilisés pour préciser les conditions hydrologiques et déterminer les paramètres hydrauliques d'un aquifère possédant une extension sous la mer. Dans cet article, un modèle tridimensionnel comprenant des eaux souterraines de densité variable a été développé pour déterminer la longueur équivalente du toit

  15. Long-term trends of surface ozone and its influencing factors at the Mt Waliguan GAW station, China - Part 2: The roles of anthropogenic emissions and climate variability

    Science.gov (United States)

    Xu, Wanyun; Xu, Xiaobin; Lin, Meiyun; Lin, Weili; Tarasick, David; Tang, Jie; Ma, Jianzhong; Zheng, Xiangdong

    2018-01-01

    Inter-annual variability and long-term trends in tropospheric ozone are both environmental and climate concerns. Ozone measured at Mt Waliguan Observatory (WLG, 3816 m a.s.l.) on the Tibetan Plateau over the period of 1994-2013 has increased significantly by 0.2-0.3 ppbv yr-1 during spring and autumn but shows a much smaller trend in winter and no significant trend in summer. Here we explore the factors driving the observed ozone changes at WLG using backward trajectory analysis, chemistry-climate model hindcast simulations (GFDL AM3), a trajectory-mapped ozonesonde data set, and several climate indices. A stratospheric ozone tracer implemented in GFDL AM3 indicates that stratosphere-to-troposphere transport (STT) can explain ˜ 60 % of the simulated springtime ozone increase at WLG, consistent with an increase in the NW air-mass frequency inferred from the trajectory analysis. Enhanced STT associated with the strengthening of the mid-latitude jet stream contributes to the observed high ozone anomalies at WLG during the springs of 1999 and 2012. During autumn, observations at WLG are more heavily influenced by polluted air masses originating from South East Asia than in the other seasons. Rising Asian anthropogenic emissions of ozone precursors are the key driver of increasing autumnal ozone observed at WLG, as supported by the GFDL AM3 model with time-varying emissions, which captures the observed ozone increase (0.26 ± 0.11 ppbv yr-1). AM3 simulates a greater ozone increase of 0.38 ± 0.11 ppbv yr-1 at WLG in autumn under conditions with strong transport from South East Asia and shows no significant ozone trend in autumn when anthropogenic emissions are held constant in time. During summer, WLG is mostly influenced by easterly air masses, but these trajectories do not extend to the polluted regions of eastern China and have decreased significantly over the last 2 decades, which likely explains why summertime ozone measured at WLG shows no significant trend

  16. Multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) and antibacterial resistance profiles of extended spectrum beta lactamase (ESBL) producing Pseudomonas aeruginosa among burnt patients in Tehran.

    Science.gov (United States)

    Jabalameli, Fereshteh; Mirsalehian, Akbar; Sotoudeh, Nazli; Jabalameli, Leila; Aligholi, Marzieh; Khoramian, Babak; Taherikalani, Morovat; Emaneini, Mohammad

    2011-11-01

    Extended spectrum β-lactamase (ESBL)-producing trait was present in 48 out of the 112 (42.8%) Pseudomonas aeruginosa isolates collected from burn wound infections during a 12-month period. The presence of oxa-10, per-1, veb-1 and ges genes and the multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) of 112 P. aeruginosa strains were determined by PCR and multiplex PCR. Disk diffusion methods were used to determine the susceptibility of the isolates to antimicrobial agents as instructed by CLSI. All ESBL isolates were resistant to aztreonam, cefepime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone and ofloxacin. Fewer than 60% of ESBL isolates were resistant to imipenem, meropenem, and piperacillin-tazobactam but more than 90% were resistant to amikacin, ciprofloxacin, levofloxacin, ticarcillin and tobramycin. The most prevalent ESBL genes included oxa-10 (70%) and per-1 (50%) followed by veb-1 (31.3%). The gene encodes GES enzyme did not detect in any isolates. A total of 100 P. aeruginosa strains were typed by MLVF typing method. MLVF produced 42 different DNA banding patterns. These data indicate that different MLVF types infect burn wounds in patients at a hospital in Tehran and also suggest an alarming rate of ESBL-producing isolates in this test location. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

  17. Temporal variability in groundwater and surface water quality in humid agricultural catchments; Driving processes and consequences for regional water quality monitoring

    NARCIS (Netherlands)

    Rozemeijer, Joachim; Van Der Velde, Ype

    2014-01-01

    Considering the large temporal variability in surface water quality is essential for adequate water quality policy and management. Neglecting these dynamics may easily lead to decreased effectiveness of measures to improve water quality and to inefficient water quality monitoring. The objective of

  18. Temporal variability in groundwater and surface water quality in humid agricultural catchments; driving processes and consequences for regional water quality monitoring

    NARCIS (Netherlands)

    Rozemeijer, J.; Velde, van der Y.

    2014-01-01

    Considering the large temporal variability in surface water quality is essential for adequate water quality policy and management. Neglecting these dynamics may easily lead to decreased effectiveness of measures to improve water quality and to inefficient water quality monitoring. The objective of

  19. The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet

    NARCIS (Netherlands)

    van den Broeke, M.R.; Smeets, C.J.P.P.; van de Wal, R.S.W.

    2011-01-01

    We present the seasonal cycle and interannual variability of the surface energy balance (SEB) in the ablation zone of the west Greenland ice sheet, using seven years (September 2003–August 2010) of hourly observations from three automatic weather stations (AWS). The AWS are situated along the 67◦ N

  20. Spatiotemporal variability of saturation excess surface runoff in flat fields due to interactions with meso- and microtopography

    NARCIS (Netherlands)

    Appels, W.M.; Noij, I.G.A.M.; Massop, H.T.L.

    2013-01-01

    Surface runoff is the fastest route from field to stream and the main transport route for sediment and adsorbed contaminants, and as such an important cause of surface water contamination in agricultural areas. The goals of the study were to explain differences in measured surface runoff volumes and

  1. Anisotropic wetting properties on a precision-ground micro-V-grooved Si surface related to their micro-characterized variables

    International Nuclear Information System (INIS)

    Li, P; Xie, J; Cheng, J; Wu, K K

    2014-01-01

    Micro-characterized variables are proposed to precisely characterize a micro-V-grooved Si surface through the 3D measured topography rather than the designed one. In this study, level and gradient micro-grooved surfaces with depth of 25–80 µm were precisely and smoothly fabricated using a new micro-grinding process rather than laser machining and chemical etching. The objective is to investigate how these accurate micro-characterized variables systematically influence anisotropic wetting and droplet self-movement on such regular micro-structured surfaces without surface chemical modification. First, the anisotropic wetting, droplet sliding, pinning effect and droplet impact were experimentally investigated; then, theoretical anisotropic wetting models were constructed to predict and design the anisotropic wetting. The experiments show that the level micro-V-grooved surface produces the anisotropic wetting and pinning effects. It not only approximates superhydrophobicity but also produces high surface free energy. Moreover, the gradient micro-V-grooved surface with large pitch may lead to much easier droplet sliding than the level one along the micro-groove. The droplet self-movement trend increases with increasing the micro-groove gradient and micro-V-groove ratio. The micro-groove pitch and depth also influence the droplet impact. Theoretical analyses show that the wetting anisotropy and the droplet anisotropy both reach their largest value and disappear for a sharp micro-groove top when the micro-V-groove ratio is equal to 0.70 and 2.58, respectively, which may change the wetting between the composite state and the non-composite state. It is confirmed that the wetting behavior may be designed and predicted by the accurate micro-characterized variables of a regular micro-structured surface. (paper)

  2. Anisotropic wetting properties on a precision-ground micro-V-grooved Si surface related to their micro-characterized variables

    Science.gov (United States)

    Li, P.; Xie, J.; Cheng, J.; Wu, K. K.

    2014-07-01

    Micro-characterized variables are proposed to precisely characterize a micro-V-grooved Si surface through the 3D measured topography rather than the designed one. In this study, level and gradient micro-grooved surfaces with depth of 25-80 µm were precisely and smoothly fabricated using a new micro-grinding process rather than laser machining and chemical etching. The objective is to investigate how these accurate micro-characterized variables systematically influence anisotropic wetting and droplet self-movement on such regular micro-structured surfaces without surface chemical modification. First, the anisotropic wetting, droplet sliding, pinning effect and droplet impact were experimentally investigated; then, theoretical anisotropic wetting models were constructed to predict and design the anisotropic wetting. The experiments show that the level micro-V-grooved surface produces the anisotropic wetting and pinning effects. It not only approximates superhydrophobicity but also produces high surface free energy. Moreover, the gradient micro-V-grooved surface with large pitch may lead to much easier droplet sliding than the level one along the micro-groove. The droplet self-movement trend increases with increasing the micro-groove gradient and micro-V-groove ratio. The micro-groove pitch and depth also influence the droplet impact. Theoretical analyses show that the wetting anisotropy and the droplet anisotropy both reach their largest value and disappear for a sharp micro-groove top when the micro-V-groove ratio is equal to 0.70 and 2.58, respectively, which may change the wetting between the composite state and the non-composite state. It is confirmed that the wetting behavior may be designed and predicted by the accurate micro-characterized variables of a regular micro-structured surface.

  3. Extended asymptotic functions - some examples

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1981-01-01

    Several examples of extended asymptotic functions of two variables are given. This type of asymptotic functions has been introduced as an extension of continuous ordinary functions. The presented examples are realizations of some Schwartz distributions delta(x), THETA(x), P(1/xsup(n)) and can be multiplied in the class of the asymptotic functions as opposed to the theory of Schwartz distributions. The examples illustrate the method of construction of extended asymptotic functions similar to the distributions. The set formed by the extended asymptotic functions is also considered. It is shown, that this set is not closed with respect to addition and multiplication

  4. Seasonal variability of surface and column carbon monoxide over the megacity Paris, high-altitude Jungfraujoch and Southern Hemispheric Wollongong stations

    Science.gov (United States)

    Té, Yao; Jeseck, Pascal; Franco, Bruno; Mahieu, Emmanuel; Jones, Nicholas; Paton-Walsh, Clare; Griffith, David W. T.; Buchholz, Rebecca R.; Hadji-Lazaro, Juliette; Hurtmans, Daniel; Janssen, Christof

    2016-09-01

    This paper studies the seasonal variation of surface and column CO at three different sites (Paris, Jungfraujoch and Wollongong), with an emphasis on establishing a link between the CO vertical distribution and the nature of CO emission sources. We find the first evidence of a time lag between surface and free tropospheric CO seasonal variations in the Northern Hemisphere. The CO seasonal variability obtained from the total columns and free tropospheric partial columns shows a maximum around March-April and a minimum around September-October in the Northern Hemisphere (Paris and Jungfraujoch). In the Southern Hemisphere (Wollongong) this seasonal variability is shifted by about 6 months. Satellite observations by the IASI-MetOp (Infrared Atmospheric Sounding Interferometer) and MOPITT (Measurements Of Pollution In The Troposphere) instruments confirm this seasonality. Ground-based FTIR (Fourier transform infrared) measurements provide useful complementary information due to good sensitivity in the boundary layer. In situ surface measurements of CO volume mixing ratios at the Paris and Jungfraujoch sites reveal a time lag of the near-surface seasonal variability of about 2 months with respect to the total column variability at the same sites. The chemical transport model GEOS-Chem (Goddard Earth Observing System chemical transport model) is employed to interpret our observations. GEOS-Chem sensitivity runs identify the emission sources influencing the seasonal variation of CO. At both Paris and Jungfraujoch, the surface seasonality is mainly driven by anthropogenic emissions, while the total column seasonality is also controlled by air masses transported from distant sources. At Wollongong, where the CO seasonality is mainly affected by biomass burning, no time shift is observed between surface measurements and total column data.

  5. Properties of the surface snow in Princess Elizabeth Land, East Antarctica - climate and non-climate dependent variability of the surface mass balance and stable water isotopic composition

    Science.gov (United States)

    Vladimirova, D.; Ekaykin, A.; Lipenkov, V.; Popov, S. V.; Petit, J. R.; Masson-Delmotte, V.

    2017-12-01

    Glaciological and meteorological observations conducted during the past four decades in Princess Elizabeth Land, East Antarctica, are compiled. The database is used to investigate spatial patterns of surface snow isotopic composition and surface mass balance, including detailed information near subglacial lake Vostok. We show diverse relationships between snow isotopic composition and surface temperature. In the most inland part (elevation 3200-3400 m a.s.l.), surface snow isotopic composition varies independently from surface temperature, and is closely related to the distance to the open water source (with a slope of 0.98±0.17 ‰ per 100 km). Surface mass balance values are higher along the ice sheet slope, and relatively evenly distributed inland. The minimum values of snow isotopic composition and surface mass balance are identified in an area XX km southwestward from Vostok station. The spatial distribution of deuterium excess delineates regions influenced by the Indian Ocean and Pacific Ocean air masses, with Vostok area being situated close to their boundary. Anomalously high deuterium excess values are observed near Dome A, suggesting high kinetic fractionation for its moisture source, or specifically high post-deposition artifacts. The dataset is available for further studies such as the assessment of skills of general circulation or regional atmospheric models, and the search for the oldest ice.

  6. Estimation of heart-position variability in 3D-surface-image-guided deep-inspiration breath-hold radiation therapy for left-sided breast cancer

    International Nuclear Information System (INIS)

    Alderliesten, Tanja; Betgen, Anja; Elkhuizen, Paula H.M.; Vliet-Vroegindeweij, Corine van; Remeijer, Peter

    2013-01-01

    Purpose: To investigate the heart position variability in deep-inspiration breath-hold (DIBH) radiation therapy (RT) for breast cancer when 3D surface imaging would be used for monitoring the BH depth during treatment delivery. For this purpose, surface setup data were compared with heart setup data. Materials and methods: Twenty patients treated with DIBH-RT after breast-conserving surgery were included. Retrospectively, heart registrations were performed for cone-beam computed tomography (CBCT) to planning CT. Further, breast-surface registrations were performed for a surface, captured concurrently with CBCT, to planning CT. The resulting setup errors were compared with linear regression analysis. Furthermore, geometric uncertainties of the heart (systematic [Σ] and random [σ]) were estimated relative to the surface registration. Based on these uncertainties planning organ at risk volume (PRV) margins for the heart were calculated: 1.3Σ − 0.5σ. Results: Moderate correlation between surface and heart setup errors was found: R 2 = 0.64, 0.37, 0.53 in left–right (LR), cranio-caudal (CC), and in anterior–posterior (AP) direction, respectively. When surface imaging would be used for monitoring, the geometric uncertainties of the heart (cm) are [Σ = 0.14, σ = 0.14]; [Σ = 0.66, σ = 0.38]; [Σ = 0.27, σ = 0.19] in LR; CC; AP. This results in PRV margins of 0.11; 0.67; 0.25 cm in LR; CC; AP. Conclusion: When DIBH-RT after breast-conserving surgery is guided by the breast-surface position then PRV margins should be used to take into account the heart-position variability relative to the breast-surface

  7. A study of angle-resolved photoemission extended fine structure as applied to the Ni 3p, Cu 3s, and Cu 3p core levels of the respective clean (111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Huff, W.R.A.; Moler, E.J.; Kellar, S.A. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    The first non-s initial state angle-resolved photoemission extended fine structure (ARPEFS) study of clean surfaces for the purpose of further understanding the technique is reported. The surface structure sensitivity of ARPEFS applied to clean surfaces and to arbitrary initial states is studied using normal photoemission data taken from the Ni 3p core levels of a Ni(111) single crystal and the Cu 3s and the Cu 3p core-levels of a Cu(111) single crystal. The Fourier transforms of these clean surface data are dominated by backscattering. Unlike the s initial state data, the p initial state data show a peak in the Fourier transform corresponding to in-plane scattering from the six nearest-neighbors to the emitter. Evidence was seen for single-scattering events from in the same plane as the emitters and double-scattering events. Using a newly developed, multiple-scattering calculation program, ARPEFS data from clean surfaces and from p initial states can be modeled to high precision. Although there are many layers of emitters when measuring photoemission from a clean surface, test calculations show that the ARPEFS signal is dominated by photoemission from atoms in the first two crystal layers. Thus, ARPEFS applied to clean surfaces is sensitive to surface reconstruction. The known contraction of the first two Cu(111) layers is confirmed. The best-fit calculation for clean Ni(111) indicates an expansion of the first two layers. To better understand the ARPEFS technique, the authors studied s and non-s initial state photoemission from clean metal surfaces.

  8. Sub-typing of extended-spectrum-β-lactamase-producing isolates from a nosocomial outbreak: application of a 10-loci generic Escherichia coli multi-locus variable number tandem repeat analysis.

    Directory of Open Access Journals (Sweden)

    Nahid Karami

    Full Text Available Extended-spectrum β-lactamase producing Escherichia coli (ESBL-E. coli were isolated from infants hospitalized in a neonatal, post-surgery ward during a four-month-long nosocomial outbreak and six-month follow-up period. A multi-locus variable number tandem repeat analysis (MLVA, using 10 loci (GECM-10, for 'generic' (i.e., non-STEC E. coli was applied for sub-species-level (i.e., sub-typing delineation and characterization of the bacterial isolates. Ten distinct GECM-10 types were detected among 50 isolates, correlating with the types defined by pulsed-field gel electrophoresis (PFGE, which is recognized to be the 'gold-standard' method for clinical epidemiological analyses. Multi-locus sequence typing (MLST, multiplex PCR genotyping of bla CTX-M, bla TEM, bla OXA and bla SHV genes and antibiotic resistance profiling, as well as a PCR assay specific for detecting isolates of the pandemic O25b-ST131 strain, further characterized the outbreak isolates. Two clusters of isolates with distinct GECM-10 types (G06-04 and G07-02, corresponding to two major PFGE types and the MLST-based sequence types (STs 131 and 1444, respectively, were confirmed to be responsible for the outbreak. The application of GECM-10 sub-typing provided reliable, rapid and cost-effective epidemiological characterizations of the ESBL-producing isolates from a nosocomial outbreak that correlated with and may be used to replace the laborious PFGE protocol for analyzing generic E. coli.

  9. Processes of 30–90 days sea surface temperature variability in the northern Indian Ocean during boreal summer

    Digital Repository Service at National Institute of Oceanography (India)

    Vialard, J.; Jayakumar, A; Gnanaseelan, C.; Lengaigne, M.; Sengupta, D.; Goswami, B.N.

    Temperature (SST) signature of this atmospheric variability, using a combination of observational datasets and Ocean General Circulation Model sensitivity experiments. In addition to the previously reported intraseasonal SST signature in the Bay of Bengal...

  10. Effect of Variable Viscosity on Vortex Instability of Non-Darcy Mixed Convection Boundary Layer Flow Adjacent to a Nonisothermal Horizontal Surface in a Porous Medium

    Directory of Open Access Journals (Sweden)

    A. M. Elaiw

    2012-01-01

    Full Text Available We study the effect of variable viscosity on the flow and vortex instability for non-Darcy mixed convection boundary layer flow on a nonisothermal horizontal plat surface in a saturated porous medium. The variation of viscosity is expressed as an exponential function of temperature. The analysis of the disturbance flow is based on linear stability theory. The base flow equations and the resulting eigenvalue problem are solved using finite difference schemes. It is found that the variable viscosity effect enhances the heat transfer rate and destabilizes the flow for liquid heating, while the opposite trend is true for gas heating.

  11. Role of the Soil Thermal Inertia in the short term variability of the surface temperature and consequences for the soil-moisture temperature feedback

    Science.gov (United States)

    Cheruy, Frederique; Dufresne, Jean-Louis; Ait Mesbah, Sonia; Grandpeix, Jean-Yves; Wang, Fuxing

    2017-04-01

    A simple model based on the surface energy budget at equilibrium is developed to compute the sensitivity of the climatological mean daily temperature and diurnal amplitude to the soil thermal inertia. It gives a conceptual framework to quantity the role of the atmospheric and land surface processes in the surface temperature variability and relies on the diurnal amplitude of the net surface radiation, the sensitivity of the turbulent fluxes to the surface temperature and the thermal inertia. The performances of the model are first evaluated with 3D numerical simulations performed with the atmospheric (LMDZ) and land surface (ORCHIDEE) modules of the Institut Pierre Simon Laplace (IPSL) climate model. A nudging approach is adopted, it prevents from using time-consuming long-term simulations required to account for the natural variability of the climate and allow to draw conclusion based on short-term (several years) simulations. In the moist regions the diurnal amplitude and the mean surface temperature are controlled by the latent heat flux. In the dry areas, the relevant role of the stability of the boundary layer and of the soil thermal inertia is demonstrated. In these regions, the sensitivity of the surface temperature to the thermal inertia is high, due to the high contribution of the thermal flux to the energy budget. At high latitudes, when the sensitivity of turbulent fluxes is dominated by the day-time sensitivity of the sensible heat flux to the surface temperature and when this later is comparable to the thermal inertia term of the sensitivity equation, the surface temperature is also partially controlled by the thermal inertia which can rely on the snow properties; In the regions where the latent heat flux exhibits a high day-to-day variability, such as transition regions, the thermal inertia has also significant impact on the surface temperature variability . In these not too wet (energy limited) and not too dry (moisture-limited) soil moisture (SM

  12. The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

    Directory of Open Access Journals (Sweden)

    V. Masson

    2013-07-01

    Full Text Available SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs or in coupled mode (from mesoscale models to numerical weather prediction and climate models. An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy. Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

  13. The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

    Science.gov (United States)

    Masson, V.; Le Moigne, P.; Martin, E.; Faroux, S.; Alias, A.; Alkama, R.; Belamari, S.; Barbu, A.; Boone, A.; Bouyssel, F.; Brousseau, P.; Brun, E.; Calvet, J.-C.; Carrer, D.; Decharme, B.; Delire, C.; Donier, S.; Essaouini, K.; Gibelin, A.-L.; Giordani, H.; Habets, F.; Jidane, M.; Kerdraon, G.; Kourzeneva, E.; Lafaysse, M.; Lafont, S.; Lebeaupin Brossier, C.; Lemonsu, A.; Mahfouf, J.-F.; Marguinaud, P.; Mokhtari, M.; Morin, S.; Pigeon, G.; Salgado, R.; Seity, Y.; Taillefer, F.; Tanguy, G.; Tulet, P.; Vincendon, B.; Vionnet, V.; Voldoire, A.

    2013-07-01

    SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs) or in coupled mode (from mesoscale models to numerical weather prediction and climate models). An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy). Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

  14. Emergence of extended spectrum beta-lactamases-producing strains belonging to cefotaxime-M-1 class from intensive care units patients and environmental surfaces in Pakistan

    Directory of Open Access Journals (Sweden)

    Aqsa Ashraf Bukhari

    2016-11-01

    Full Text Available Aim: The emergence of multidrug-resistant (MDR bacteria is the most dangerous threat for the treatment of infectious diseases. The aim of this study was to detect and characterize extended spectrum beta-lactamases (ESBLs and carbapenemase-producing Klebsiella pneumoniae and Escherichia coli among patients and environment of intensive care units (ICUs of three tertiary care hospitals in Pakistan. Materials and Methods: A total of 82 samples from ICU’s patients and inanimate environment (injection trays, wash basins, door handles, hand swabs of professionals, and ICU fridges were screened for ESBL by culturing on CHROMagar-ESBL. ESBL and carbapenemases production were confirmed by double disc synergy test and modified Hodge’s test, respectively. Polymerase chain reaction was used to detect ESBL encoding genes bla cefotaxime (CTX-M, blaCTX-M-1, blaCTX-M-2, blaCTX-M-9, blaTEM, blaSHV and carbapenemase genes blaKPC, bla New Delhi metallo-beta-lactamase-1, blaOXA-48 and blaVIM. Results: Overall, ESBL production was found high 30/82 (36.5% among isolates of which 15.8% K. pneumoniae and 20.7% E. coli were identified. All the K. pneumoniae and majority of E. coli isolates were MDR, i.e., resistance to three or more antimicrobial categories. Molecular characterization showed the blaCTX-M-1 as the predominant genotype found in 17/21 (80% of the isolates. None of the strains was found positive for carbapenemase-encoding genes. Conclusion: In conclusion, this study demonstrates the emergence of MDR ESBL producing strains among ICU patients and hospital environment, posing a serious threat for the control of nosocomial infections.

  15. ClimoBase: Rouse Canadian Surface Observations of Weather, Climate, and Hydrological Variables, 1984-1998, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — ClimoBase is a collection of surface climate measurements collected in Northern Canada by Dr. Wayne Rouse between 1984 and 1998 in three locations: Churchill,...

  16. Surface temperature evolution and the location of maximum and average surface temperature of a lithium-ion pouch cell under variable load profiles

    DEFF Research Database (Denmark)

    Goutam, Shovon; Timmermans, Jean-Marc; Omar, Noshin

    2014-01-01

    This experimental work attempts to determine the surface temperature evolution of large (20 Ah-rated capacity) commercial Lithium-Ion pouch cells for the application of rechargeable energy storage of plug in hybrid electric vehicles and electric vehicles. The cathode of the cells is nickel...

  17. Extended Poisson Exponential Distribution

    Directory of Open Access Journals (Sweden)

    Anum Fatima

    2015-09-01

    Full Text Available A new mixture of Modified Exponential (ME and Poisson distribution has been introduced in this paper. Taking the Maximum of Modified Exponential random variable when the sample size follows a zero truncated Poisson distribution we have derived the new distribution, named as Extended Poisson Exponential distribution. This distribution possesses increasing and decreasing failure rates. The Poisson-Exponential, Modified Exponential and Exponential distributions are special cases of this distribution. We have also investigated some mathematical properties of the distribution along with Information entropies and Order statistics of the distribution. The estimation of parameters has been obtained using the Maximum Likelihood Estimation procedure. Finally we have illustrated a real data application of our distribution.

  18. Generalization of experimental data and development of recommendations for calculating heat transfer of a staggered tube bank with helical and ring extended-surface tubes in a perpendicular gas stream (for new formulation of standard method for boiler heat analyses)

    Energy Technology Data Exchange (ETDEWEB)

    Fomina, V N; Titova, E Ya; Migai, V K; Bystrov, P G; Pis' mennyi, E N [Vsesoyuznyi Teplotekhnicheskii Institut (USSR)

    1991-06-01

    Comparatively evaluates methods for determination of optimum design of extended-surface tubes used in water walls of boilers fired with coal and other fuels in commercial power plants in the USSR. The standard calculation methods introduced in 1973 and other methods developed and tested by individual research institutes of the USSR are described. New and original formulae based on the results of physical and mathematical modeling are evaluated. Heat transfer from flue gases to water walls is analyzed. Arrangement of tube banks, design of extended-surface tubes and other factors that influence heat transfer are considered. Evaluations show that from among the analyzed calculation methods the method developed by the KPI institute is superior to others (it is most accurate and universal). Investigations show that the coefficient of thermal efficiency of the economizers (1st and 2nd stage) of boilers fired with coal amounts to about 0.85. The coefficient considers effects of buildup on the economizer tubes. Use of the method is explained on example of boilers fired with black coal from the Ehkibastuz. 13 refs.

  19. Time Scales of the European Surface Air Temperature Variability: The Role of the 7-8 Year Cycle

    Czech Academy of Sciences Publication Activity Database

    Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, S.; Tsonis, A.A.; Paluš, Milan

    2016-01-01

    Roč. 43, č. 2 (2016), s. 902-909 ISSN 0094-8276 R&D Projects: GA MŠk LH14001 Institutional support: RVO:67985807 Keywords : 7-8 year cycle * air temperature variability * annual cycle amplitude * cross-scale interactions * seasonality * time scales Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 4.253, year: 2016

  20. RIMAPS characterization of a surface in the variable aperture fracture model and determination of the main paths for water flow

    International Nuclear Information System (INIS)

    Fuentes, Nestor O.

    2003-01-01

    To understand the real incidence of fracture geometry in the unsteady behavior of flowing water channels, the RIMAPS (Rotated Image with Maximum Average Power Spectrum) technique is used to determine the main directions of these channels. This new characterization technique works on digitized images obtained from the surfaces under study. The present work presents the results of a comparison between the flow directions predicted by RIMAPS and the real channels directions observed in a laboratory experiment. A perfect accordance was verified between the directions obtained in both cases. It can be concluded from these results that geometrical characteristics of a fracture surface determine the main path directions for water flow. (author)

  1. The 30-60-day Intraseasonal Variability of Sea Surface Temperature in the South China Sea dur1ing May-September

    Science.gov (United States)

    Mao, Jiangyu; Wang, Ming

    2018-05-01

    This study investigates the structure and propagation of intraseasonal sea surface temperature (SST) variability in the South China Sea (SCS) on the 30-60-day timescale during boreal summer (May-September). TRMM-based SST, GODAS oceanic reanalysis and ERA-Interim atmospheric reanalysis datasets from 1998 to 2013 are used to examine quantitatively the atmospheric thermodynamic and oceanic dynamic mechanisms responsible for its formation. Power spectra show that the 30-60-day SST variability is predominant, accounting for 60% of the variance of the 10-90-day variability over most of the SCS. Composite analyses demonstrate that the 30-60-day SST variability is characterized by the alternate occurrence of basin-wide positive and negative SST anomalies in the SCS, with positive (negative) SST anomalies accompanied by anomalous northeasterlies (southwesterlies). The transition and expansion of SST anomalies are driven by the monsoonal trough-ridge seesaw pattern that migrates northward from the equator to the northern SCS. Quantitative diagnosis of the composite mixed-layer heat budgets shows that, within a strong 30-60-day cycle, the atmospheric thermal forcing is indeed a dominant factor, with the mixed-layer net heat flux (MNHF) contributing around 60% of the total SST tendency, while vertical entrainment contributes more than 30%. However, the entrainment-induced SST tendency is sometimes as large as the MNHF-induced component, implying that ocean processes are sometimes as important as surface fluxes in generating the 30-60-day SST variability in the SCS.

  2. Heterogeneity of soil surface ammonium concentration and other characteristics, related to plant specific variability in a Mediterranean-type ecosystem

    International Nuclear Information System (INIS)

    Cruz, Cristina; Bio, Ana M.F.; Jullioti, Aldo; Tavares, Alice; Dias, Teresa; Martins-Loucao, Maria Amelia

    2008-01-01

    Heterogeneity and dynamics of eight soil surface characteristics essential for plants-ammonium and nitrate concentrations, water content, temperature, pH, organic matter, nitrification and ammonification rates-were studied in a Mediterranean-type ecosystem on four occasions over a year. Soil properties varied seasonally and were influenced by plant species. Nitrate and ammonium were present in the soil at similar concentrations throughout the year. The positive correlation between them at the time of greatest plant development indicates that ammonium is a readily available nitrogen source in Mediterranean-type ecosystems. The results presented here suggest that plant cover significantly affects soil surface characteristics. - In Mediterranean-type ecosystems ammonium is present in the soil throughout the year and its concentration is dependent on plant cover

  3. Variable-focus microscopy and UV surface dissolution imaging as complementary techniques in intrinsic dissolution rate determination

    DEFF Research Database (Denmark)

    Ward, Adam; Walton, Karl; Box, Karl

    2017-01-01

    -SDI run, have been measured using a non-contact, optical, three-dimensional microscope based on focus variation, the Alicona Infinite Focus Microscope, with the aim of correlating the IDRs to the surface properties. Ibuprofen (IBU) was used as a model poorly-soluble drug. DSC and XRD were used to monitor...... possible polymorphic changes that may have occurred post-compaction and post-SDI run. IBUs IDR decreased from 0.033mg/min/cm(2) to 0.022mg/min/cm(2) from 10 to 20min, respectively, during the experiment. XRD and DSC showed no form changes during the SDI run. The surface topography images showed...

  4. Spatial Patterns of Variability in Antarctic Surface Temperature: Connections to the Southern Hemisphere Annular Mode and the Southern Oscillation

    Science.gov (United States)

    Kwok, Ron; Comiso, Josefino C.; Koblinsky, Chester J. (Technical Monitor)

    2002-01-01

    The 17-year (1982-1998) trend in surface temperature shows a general cooling over the Antarctic continent, warming of the sea ice zone, with moderate changes over the oceans. Warming of the peripheral seas is associated with negative trends in the regional sea ice extent. Effects of the Southern Hemisphere Annular Mode (SAM) and the extrapolar Southern Oscillation (SO) on surface temperature are quantified through regression analysis. Positive polarities of the SAM are associated with cold anomalies over most of Antarctica, with the most notable exception of the Antarctic Peninsula. Positive temperature anomalies and ice edge retreat in the Pacific sector are associated with El Nino episodes. Over the past two decades, the drift towards high polarity in the SAM and negative polarity in the SO indices couple to produce a spatial pattern with warmer temperatures in the Antarctic Peninsula and peripheral seas, and cooler temperatures over much of East Antarctica.

  5. Charge Dynamics in near-Surface, Variable-Density Ensembles of Nitrogen-Vacancy Centers in Diamond.

    Science.gov (United States)

    Dhomkar, Siddharth; Jayakumar, Harishankar; Zangara, Pablo R; Meriles, Carlos A

    2018-06-13

    Although the spin properties of superficial shallow nitrogen-vacancy (NV) centers have been the subject of extensive scrutiny, considerably less attention has been devoted to studying the dynamics of NV charge conversion near the diamond surface. Using multicolor confocal microscopy, here we show that near-surface point defects arising from high-density ion implantation dramatically increase the ionization and recombination rates of shallow NVs compared to those in bulk diamond. Further, we find that these rates grow linearly, not quadratically, with laser intensity, indicative of single-photon processes enabled by NV state mixing with other defect states. Accompanying these findings, we observe NV ionization and recombination in the dark, likely the result of charge transfer to neighboring traps. Despite the altered charge dynamics, we show that one can imprint rewritable, long-lasting patterns of charged-initialized, near-surface NVs over large areas, an ability that could be exploited for electrochemical biosensing or to optically store digital data sets with subdiffraction resolution.

  6. Vertical variability of seawater DMS in the South Pacific Ocean and its implication for atmospheric and surface seawater DMS.

    Science.gov (United States)

    Lee, Gangwoong; Park, Jooyoung; Jang, Yuwoon; Lee, Meehye; Kim, Kyung-Ryul; Oh, Jae-Ryoung; Kim, Dongseon; Yi, Hi-Il; Kim, Tong-Yup

    2010-02-01

    Shipboard measurements of atmospheric dimethylsulfide (DMS) and sea surface water DMS were performed aboard the R/V Onnuri across the South Pacific from Santiago, Chile to Fiji in February 2000. Hydrographic profiles of DMS, dissolved dimethylsulfoniopropionate (DMSP(d)), and particulate DMSP(p) in the upper 200m were obtained at 16 stations along the track. Atmospheric and sea surface water DMS concentrations ranged from 3 to 442pptv and from 0.1 to 19.9nM, respectively; the mean values of 61pptv and 2.1nM, respectively, were comparable to those from previous studies in the South Pacific. The South Pacific Gyre was distinguished by longitudinal-vertical distributions of DMS, DMSP(d), and DMSP(p), which was thought to be associated with the characteristic modification of biological activities that occurs mainly due to significant change in water temperature. The averaged DMS maximum appeared at 40m depth, whereas DMSP(p) and DMSP(d) maxima coincided with that of dissolved oxygen content at 60-80m. The sea-to-air fluxes of DMS were estimated to be 0.4-11.3micromold(-1)m(-2) (mean=2.8micromold(-1)m(-2)). A fairly good correlation between atmospheric DMS and sea-to-air DMS flux indicated that atmospheric DMS concentration was more sensitive to change in physical parameters than its photochemical removal process or surface seawater DMS concentrations.

  7. Decomposing Shortwave Top-of-Atmosphere Radiative Flux Variability in Terms of Surface and Atmospheric Contributions Using CERES Observations

    Science.gov (United States)

    Loeb, N. G.; Wong, T.; Wang, H.

    2017-12-01

    Earth's climate is determined by the exchange of radiant energy between the Sun, Earth and space. The absorbed solar radiation (ASR) fuels the climate system, providing the energy required for atmospheric and oceanic motions, while the system cools by emitting outgoing longwave (LW) radiation to space. A central objective of the Clouds and the Earth's Radiant Energy System (CERES) is to produce a long-term global climate data record of Earth's radiation budget along with the associated atmospheric and surface properties that influence it. CERES data products utilize a number of data sources, including broadband radiometers measuring incoming and reflected solar radiation and OLR, polar orbiting and geostationary spectral imagers, meteorological, aerosol and ozone assimilation data, and snow/sea-ice maps based on microwave radiometer data. Here we use simple diagnostic model of Earth's albedo and CERES Energy Balanced and Filled (EBAF) Ed4.0 data for March 2000-February 2016 to quantify interannual variations in SW TOA flux associated with surface albedo and atmospheric reflectance and transmittance variations. Surface albedo variations account for cloud properties over the Arctic Ocean.

  8. Optimization of operating variables for production of ultra-fine talc in a stirred mill. Specific surface area investigations

    Directory of Open Access Journals (Sweden)

    Toraman Oner Yusuf

    2016-01-01

    Full Text Available Due to its properties such as chemical inertness, softness, whiteness, high thermal conductivity, low electrical conductivity and adsorption properties talc has wide industrial applications in paper, cosmetics, paints, polymer, ceramics, refractory materials and pharmaceutical. The demand for ultra-fine talc is emerging which drives the mineral industry to produce value added products. In this study, it was investigated how certain grinding parameters such as mill speed, ball filling ratio, powder filling ratio and grinding time of dry stirred mill affect grindability of talc ore (d97=127 μm. A series of laboratory experiments using a 24 full factorial design was conducted to determine the optimal operational parameters of a stirred mill in order to minimize the specific surface area. The main and interaction effects on the volume specific surface area (SV, m2.cm−3 of the ground product were evaluated using the Yates analysis. Under the optimal conditions at the stirrer speed of 600 rpm, grinding time of 20 min, sample mass of 5% and ball ratio of 70%, the resulting talc powder had larger volume specific surface area (i.e., 3.48 m2.cm−3 than the starting material (i.e., 1.84 m2.cm−3.

  9. Coupling between marine boundary layer clouds and summer-to-summer sea surface temperature variability over the North Atlantic and Pacific

    Science.gov (United States)

    Myers, Timothy A.; Mechoso, Carlos R.; DeFlorio, Michael J.

    2018-02-01

    Climate modes of variability over the Atlantic and Pacific may be amplified by a positive feedback between sea-surface temperature (SST) and marine boundary layer clouds. However, it is well known that climate models poorly simulate this feedback. Does this deficiency contribute to model-to-model differences in the representation of climate modes of variability? Over both the North Atlantic and Pacific, typical summertime interannual to interdecadal SST variability exhibits horseshoe-like patterns of co-located anomalies of shortwave cloud radiative effect (CRE), low-level cloud fraction, SST, and estimated inversion strength over the subtropics and midlatitudes that are consistent with a positive cloud feedback. During winter over the midlatitudes, this feedback appears to be diminished. Models participating in the Coupled Model Intercomparison Project phase 5 that simulate a weak feedback between subtropical SST and shortwave CRE produce smaller and less realistic amplitudes of summertime SST and CRE variability over the northern oceans compared to models with a stronger feedback. The change in SST amplitude per unit change in CRE amplitude among the models and observations may be understood as the temperature response of the ocean mixed layer to a unit change in radiative flux over the course of a season. These results highlight the importance of boundary layer clouds in interannual to interdecadal atmosphere-ocean variability over the northern oceans during summer. The results also suggest that deficiencies in the simulation of these clouds in coupled climate models contribute to underestimation in their simulation of summer-to-summer SST variability.

  10. Peeking Below the Snow Surface to Explore Amundsen Sea Climate Variability and Locate Optimal Ice-Core Sites

    Science.gov (United States)

    Neff, P. D.; Fudge, T. J.; Medley, B.

    2016-12-01

    Observations over recent decades reveal rapid changes in ice shelves and fast-flowing grounded ice along the Amundsen Sea coast of the West Antarctic Ice Sheet (WAIS). Long-term perspectives on this ongoing ice loss are needed to address a central question of Antarctic research: how much and how fast will Antarctic ice-loss raise sea level? Ice cores can provide insight into past variability of the atmospheric (wind) forcing of regional ocean dynamics affecting ice loss. Interannual variability of snow accumulation on coastal ice domes grounded near or within ice shelves reflects local to regional atmospheric circulation near the ice-ocean interface. Records of snow accumulation inferred from shallow ice cores strongly correlate with reanalysis precipitation and pressure fields, but ice cores have not yet been retrieved along the Amundsen Sea coast. High-frequency airborne radar data (NASA Operation IceBridge), however, have been collected over this region and we demonstrate that these data accurately reflect annual stratigraphy in shallow snow and firn (1 to 2 decades of accumulation). This further validates the agreement between radar snow accumulation records and climate reanalysis products. We then explore regional climate controls on local snow accumulation through comparison with gridded reanalysis products, providing a preview of what information longer coastal ice core records may provide with respect to past atmospheric forcing of ocean circulation and WAIS ice loss.

  11. Variability of {sup 10}Be and {delta}{sup 18}O in snow pits from Greenland and a surface traverse from Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Berggren, A.-M. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Aldahan, A., E-mail: ala.aldahan@geo.uu.se [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates); Possnert, G. [Tandem Laboratory, Uppsala University, P.O. Box 529, 751 20 Uppsala (Sweden); Hansson, M. [Dept. of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm (Sweden); Steen-Larsen, H.C. [Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej, 30,2100 Copenhagen (Denmark); Sturevik Storm, A. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Moerth, C.-M. [Dept. of Geology and Geochemistry, Stockholm University, 106 91 Stockholm (Sweden); Murad, A. [Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates)

    2013-01-15

    To examine temporal variability of {sup 10}Be in glacial ice, we sampled snow to a depth of 160 cm at the NEEM (North Greenland Eemian Ice Drilling) drilling site in Greenland. The samples span three years between the summers of 2006 and 2009. At the same time, spatial variability of {sup 10}Be in glacial ice was explored through collection of the upper {approx}5 cm of surface snow in Antarctica during part of the Swedish-Japanese traverse from Svea to Syowa station during the austral summer in 2007-2008. The results of the Greenlandic {sup 10}Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the {delta}{sup 18}O data. The {sup 10}Be concentration variability most likely reflects also effects of aerosol loading and deposition pathways, possibly in combination with post-depositional processes. The Antarctic traverse data expose a negative correlation between {sup 10}Be and {delta}{sup 18}O, while there are weaker but still significant correlations to altitude and distance to the coast (approximated by the distance to the 70th latitude). These relationships indicate that geographical factors, mainly the proximity to the coast, may strongly affect {sup 10}Be concentrations in snow in Queen Maud Land, Antarctica.

  12. How Far Can Extended Knowledge Be Extended?

    DEFF Research Database (Denmark)

    Wray, K. Brad

    2018-01-01

    by an artifact, like a notebook or telescope. The chapter illustrates this by applying Pritchard’s account of extended knowledge to collaborating scientists. The beliefs acquired through collaborative research cannot satisfy both of Pritchard’s conditions of creditability. Further, there is evidence......Duncan Pritchard (2010) has developed a theory of extended knowledge based on the notion of extended cognition initially developed by Clark and Chalmers (1998). Pritchard’s account gives a central role to the notion of creditability, which requires the following two conditions to be met: (i...... that scientists are not prepared to take responsibility for the actions of the scientists with whom they collaborate....

  13. Improved imaging of cochlear nerve hypoplasia using a 3-Tesla variable flip-angle turbo spin-echo sequence and a 7-cm surface coil.

    Science.gov (United States)

    Giesemann, Anja M; Raab, Peter; Lyutenski, Stefan; Dettmer, Sabine; Bültmann, Eva; Frömke, Cornelia; Lenarz, Thomas; Lanfermann, Heinrich; Goetz, Friedrich

    2014-03-01

    Magnetic resonance imaging of the temporal bone has an important role in decision making with regard to cochlea implantation, especially in children with cochlear nerve deficiency. The purpose of this study was to evaluate the usefulness of the combination of an advanced high-resolution T2-weighted sequence with a surface coil in a 3-Tesla magnetic resonance imaging scanner in cases of suspected cochlear nerve aplasia. Prospective study. Seven patients with cochlear nerve hypoplasia or aplasia were prospectively examined using a high-resolution three-dimensional variable flip-angle turbo spin-echo sequence using a surface coil, and the images were compared with the same sequence in standard resolution using a standard head coil. Three neuroradiologists evaluated the magnetic resonance images independently, rating the visibility of the nerves in diagnosing hypoplasia or aplasia. Eight ears in seven patients with hypoplasia or aplasia of the cochlear nerve were examined. The average age was 2.7 years (range, 9 months-5 years). Seven ears had accompanying malformations. The inter-rater reliability in diagnosing hypoplasia or aplasia was greater using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence (fixed-marginal kappa: 0.64) than with the same sequence in lower resolution (fixed-marginal kappa: 0.06). Examining cases of suspected cochlear nerve aplasia using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence in combination with a surface coil shows significant improvement over standard methods. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  14. Surface Transient Binding-Based Fluorescence Correlation Spectroscopy (STB-FCS), a Simple and Easy-to-Implement Method to Extend the Upper Limit of the Time Window to Seconds.

    Science.gov (United States)

    Peng, Sijia; Wang, Wenjuan; Chen, Chunlai

    2018-05-10

    Fluorescence correlation spectroscopy is a powerful single-molecule tool that is able to capture kinetic processes occurring at the nanosecond time scale. However, the upper limit of its time window is restricted by the dwell time of the molecule of interest in the confocal detection volume, which is usually around submilliseconds for a freely diffusing biomolecule. Here, we present a simple and easy-to-implement method, named surface transient binding-based fluorescence correlation spectroscopy (STB-FCS), which extends the upper limit of the time window to seconds. We further demonstrated that STB-FCS enables capture of both intramolecular and intermolecular kinetic processes whose time scales cross several orders of magnitude.

  15. Intra-urban spatial variability of surface ozone in Riverside, CA: viability and validation of low-cost sensors

    Science.gov (United States)

    Sadighi, Kira; Coffey, Evan; Polidori, Andrea; Feenstra, Brandon; Lv, Qin; Henze, Daven K.; Hannigan, Michael

    2018-03-01

    Sensor networks are being more widely used to characterize and understand compounds in the atmosphere like ozone (O3). This study employs a measurement tool, called the U-Pod, constructed at the University of Colorado Boulder, to investigate spatial and temporal variability of O3 in a 200 km2 area of Riverside County near Los Angeles, California. This tool contains low-cost sensors to collect ambient data at non-permanent locations. The U-Pods were calibrated using a pre-deployment field calibration technique; all the U-Pods were collocated with regulatory monitors. After collocation, the U-Pods were deployed in the area mentioned. A subset of pods was deployed at two local regulatory air quality monitoring stations providing validation for the collocation calibration method. Field validation of sensor O3 measurements to minute-resolution reference observations resulted in R2 and root mean squared errors (RMSEs) of 0.95-0.97 and 4.4-5.9 ppbv, respectively. Using the deployment data, ozone concentrations were observed to vary on this small spatial scale. In the analysis based on hourly binned data, the median R2 values between all possible U-Pod pairs varied from 0.52 to 0.86 for ozone during the deployment. The medians of absolute differences were calculated between all possible pod pairs, 21 pairs total. The median values of those median absolute differences for each hour of the day varied between 2.2 and 9.3 ppbv for the ozone deployment. Since median differences between U-Pod concentrations during deployment are larger than the respective root mean square error values, we can conclude that there is spatial variability in this criteria pollutant across the study area. This is important because it means that citizens may be exposed to more, or less, ozone than they would assume based on current regulatory monitoring.

  16. Extending the range of low energy electron diffraction (LEED) surface structure determination: Co-adsorbed molecules, incommensurate overlayers and alloy surface order studied by new video and electron counting LEED techniques

    International Nuclear Information System (INIS)

    Ogletree, D.F.

    1986-11-01

    LEED multiple scattering theory is briefly summarized, and aspects of electron scattering with particular significance to experimental measurements such as electron beam coherence, instrument response and phonon scattering are analyzed. Diffuse LEED experiments are discussed. New techniques that enhance the power of LEED are described, including a real-time video image digitizer applied to LEED intensity measurements, along with computer programs to generate I-V curves. The first electron counting LEED detector using a ''wedge and strip'' position sensitive anode and digital electronics is described. This instrument uses picoampere incident beam currents, and its sensitivity is limited only by statistics and counting times. Structural results on new classes of surface systems are presented. The structure of the c(4 x 2) phase of carbon monoxide adsorbed on Pt(111) has been determined, showing that carbon monoxide molecules adsorb in both top and bridge sites, 1.85 +- 0.10 A and 1.55 +- 0.10 A above the metal surface, respectively. The structure of an incommensurate graphite overlayer on Pt(111) is analyzed. The graphite layer is 3.70 +- 0.05 A above the metal surface, with intercalated carbon atoms located 1.25 +- 0.10 A above hollow sites supporting it. The (2√3 x 4)-rectangular phase of benzene and carbon monoxide coadsorbed on Pt(111) is analyzed. Benzene molecules adsorb in bridge sites parallel to and 2.10 +- 0.10 A above the surface. The carbon ring is expanded, with an average C-C bond length of 1.72 +- 0.15 A. The carbon monoxide molecules also adsorb in bridge sites. The structure of the (√3 x √3) reconstruction on the (111) face of the α-CuAl alloy has been determined

  17. Extending the range of low energy electron diffraction (LEED) surface structure determination: Co-adsorbed molecules, incommensurate overlayers and alloy surface order studied by new video and electron counting LEED techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ogletree, D.F.

    1986-11-01

    LEED multiple scattering theory is briefly summarized, and aspects of electron scattering with particular significance to experimental measurements such as electron beam coherence, instrument response and phonon scattering are analyzed. Diffuse LEED experiments are discussed. New techniques that enhance the power of LEED are described, including a real-time video image digitizer applied to LEED intensity measurements, along with computer programs to generate I-V curves. The first electron counting LEED detector using a ''wedge and strip'' position sensitive anode and digital electronics is described. This instrument uses picoampere incident beam currents, and its sensitivity is limited only by statistics and counting times. Structural results on new classes of surface systems are presented. The structure of the c(4 x 2) phase of carbon monoxide adsorbed on Pt(111) has been determined, showing that carbon monoxide molecules adsorb in both top and bridge sites, 1.85 +- 0.10 A and 1.55 +- 0.10 A above the metal surface, respectively. The structure of an incommensurate graphite overlayer on Pt(111) is analyzed. The graphite layer is 3.70 +- 0.05 A above the metal surface, with intercalated carbon atoms located 1.25 +- 0.10 A above hollow sites supporting it. The (2..sqrt..3 x 4)-rectangular phase of benzene and carbon monoxide coadsorbed on Pt(111) is analyzed. Benzene molecules adsorb in bridge sites parallel to and 2.10 +- 0.10 A above the surface. The carbon ring is expanded, with an average C-C bond length of 1.72 +- 0.15 A. The carbon monoxide molecules also adsorb in bridge sites. The structure of the (..sqrt..3 x ..sqrt..3) reconstruction on the (111) face of the ..cap alpha..-CuAl alloy has been determined.

  18. Dissolved inorganic carbon, pH, oxygen, and other variables collected from surface discrete and surface underway observations using flow-through pump from NOAA Ship Gordon Gunter off the U.S. East Coast during the East Coast Ocean Acidification (ECOA) Cruise from 2015-06-19 to 2015-07-24 (NCEI Accession 0157485)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains dissolved inorganic carbon, pH, oxygen, and other variables collected from surface discrete and surface underway observations during...

  19. Seasonal variability in the surface sediments of Mobile Bay, Alabama, recorded by geochemistry and foraminifera, 2009–2010

    Science.gov (United States)

    Umberger, D.K.; Osterman, L.E.; Smith, C.G.; Frazier, J.; Richwine, K.A.

    2012-01-01

    A study was undertaken in order to document and quantify recent environmental change in Mobile Bay, Alabama. The study was part of the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility project, a regional project funded by the Coastal and Marine Geology Program to understand how natural forcings and anthropogenic modifications influence coastal ecosystems and their susceptibility to coastal hazards. Mobile Bay is a large drowned-river estuary that has been modified significantly by humans to accommodate the Port of Mobile. Examples include repeated dredging of a large shipping channel down the central axis of the bay and construction of a causeway across the head of the bay and at the foot of the bayhead delta. In addition to modifications, the bay is also known to have episodic periods of low oxygen (hypoxia) that result in significant mortality to fish and benthic organisms (May, 1973). For this study a series of surface sediment samples were collected. Surface benthic foraminiferal and bulk geochemical data provide the modern baseline conditions of the bay and can be used as a reference to changing environmental parameters in the past (Osterman and Smith, in press) and into the future. This report archives data collected as part of the Mobile Bay Study that may be used in future environmental change studies.

  20. Effect of silica nanoparticles with variable size and surface functionalization on human endothelial cell viability and angiogenic activity

    Science.gov (United States)

    Guarnieri, Daniela; Malvindi, Maria Ada; Belli, Valentina; Pompa, Pier Paolo; Netti, Paolo

    2014-02-01

    Silica nanoparticles could be promising delivery vehicles for drug targeting or gene therapy. However, few studies have been undertaken to determine the biological behavior effects of silica nanoparticles on primary endothelial cells. Here we investigated uptake, cytotoxicity and angiogenic properties of silica nanoparticle with positive and negative surface charge and sizes ranging from 25 to 115 nm in primary human umbilical vein endothelial cells. Dynamic light scattering measurements and nanoparticle tracking analysis were used to estimate the dispersion status of nanoparticles in cell culture media, which was a key aspect to understand the results of the in vitro cellular uptake experiments. Nanoparticles were taken up by primary endothelial cells in a size-dependent manner according to their degree of agglomeration occurring after transfer in cell culture media. Functionalization of the particle surface with positively charged groups enhanced the in vitro cellular uptake, compared to negatively charged nanoparticles. However, this effect was contrasted by the tendency of particles to form agglomerates, leading to lower internalization efficiency. Silica nanoparticle uptake did not affect cell viability and cell membrane integrity. More interestingly, positively and negatively charged 25 nm nanoparticles did not influence capillary-like tube formation and angiogenic sprouting, compared to controls. Considering the increasing interest in nanomaterials for several biomedical applications, a careful study of nanoparticle-endothelial cells interactions is of high relevance to assess possible risks associated to silica nanoparticle exposure and their possible applications in nanomedicine as safe and effective nanocarriers for vascular transport of therapeutic agents.

  1. Seismic behavior of NPP structures subjected to realistic 3D, inclined seismic motions, in variable layered soil/rock, on surface or embedded foundations

    International Nuclear Information System (INIS)

    Jeremić, B.; Tafazzoli, N.; Ancheta, T.; Orbović, N.; Blahoianu, A.

    2013-01-01

    Highlights: • Full 3D, inclined, incoherent seismic motions used for modeling SSI of an NPP. • Analyzed effects of variable and uniform soil/rock layering profiles on SSI. • Surface and embedded foundations were modeled and differences analyzed. - Abstract: Presented here is an investigation of the seismic response of a massive NPP structures due to full 3D, inclined, un-correlated input motions for different soil and rock profiles. Of particular interest are the effects of soil and rock layering on the response and the changes of input motions (frequency characteristics) due to such layering. In addition to rock/soil layering effects, investigated are also effects of foundation embedment on dynamic response. Significant differences were observed in dynamic response of containment and internal structure founded on surface and on embedded foundations. These differences were observed for both rock and soil profiles. Select results are used to present most interesting findings

  2. The extended bigraded Toda hierarchy

    International Nuclear Information System (INIS)

    Carlet, Guido

    2006-01-01

    We generalize the Toda lattice hierarchy by considering N + M dependent variables. We construct roots and logarithms of the Lax operator which are uniquely defined operators with coefficients that are ε-series of differential polynomials in the dependent variables, and we use them to provide a Lax pair definition of the extended bigraded Toda hierarchy, generalizing [4]. Using R-matrix theory we give the bi-Hamiltonian formulation of this hierarchy and we prove the existence of a tau function for its solutions. Finally we study the dispersionless limit and its connection with a class of Frobenius manifolds on the orbit space of the extended affine Weyl groups W-tilde (N) (A N+M-1 ) of the A series, defined by Dubrovin and Zhang (1998 Compos. Math. 111 167)

  3. Modeling the contributions of global air temperature, synoptic-scale phenomena and soil moisture to near-surface static energy variability using artificial neural networks

    Science.gov (United States)

    Pryor, Sara C.; Sullivan, Ryan C.; Schoof, Justin T.

    2017-12-01

    The static energy content of the atmosphere is increasing on a global scale, but exhibits important subglobal and subregional scales of variability and is a useful parameter for integrating the net effect of changes in the partitioning of energy at the surface and for improving understanding of the causes of so-called warming holes (i.e., locations with decreasing daily maximum air temperatures (T) or increasing trends of lower magnitude than the global mean). Further, measures of the static energy content (herein the equivalent potential temperature, θe) are more strongly linked to excess human mortality and morbidity than air temperature alone, and have great relevance in understanding causes of past heat-related excess mortality and making projections of possible future events that are likely to be associated with negative human health and economic consequences. New nonlinear statistical models for summertime daily maximum and minimum θe are developed and used to advance understanding of drivers of historical change and variability over the eastern USA. The predictor variables are an index of the daily global mean temperature, daily indices of the synoptic-scale meteorology derived from T and specific humidity (Q) at 850 and 500 hPa geopotential heights (Z), and spatiotemporally averaged soil moisture (text">SM). text">SM is particularly important in determining the magnitude of θe over regions that have previously been identified as exhibiting warming holes, confirming the key importance of text">SM in dictating the partitioning of net radiation into sensible and latent heat and dictating trends in near-surface T and θe. Consistent with our a priori expectations, models built using artificial neural networks (ANNs) out-perform linear models that do not permit interaction of the predictor variables (global T, synoptic-scale meteorological conditions and text">SM). This is particularly marked in regions with high variability in minimum and maximum θe, where

  4. Genomic Characterization of Variable Surface Antigens Reveals a Telomere Position Effect as a Prerequisite for RNA Interference-Mediated Silencing in Paramecium tetraurelia

    Science.gov (United States)

    Baranasic, Damir; Oppermann, Timo; Cheaib, Miriam; Cullum, John; Schmidt, Helmut

    2014-01-01

    ABSTRACT Antigenic or phenotypic variation is a widespread phenomenon of expression of variable surface protein coats on eukaryotic microbes. To clarify the mechanism behind mutually exclusive gene expression, we characterized the genetic properties of the surface antigen multigene family in the ciliate Paramecium tetraurelia and the epigenetic factors controlling expression and silencing. Genome analysis indicated that the multigene family consists of intrachromosomal and subtelomeric genes; both classes apparently derive from different gene duplication events: whole-genome and intrachromosomal duplication. Expression analysis provides evidence for telomere position effects, because only subtelomeric genes follow mutually exclusive transcription. Microarray analysis of cultures deficient in Rdr3, an RNA-dependent RNA polymerase, in comparison to serotype-pure wild-type cultures, shows cotranscription of a subset of subtelomeric genes, indicating that the telomere position effect is due to a selective occurrence of Rdr3-mediated silencing in subtelomeric regions. We present a model of surface antigen evolution by intrachromosomal gene duplication involving the maintenance of positive selection of structurally relevant regions. Further analysis of chromosome heterogeneity shows that alternative telomere addition regions clearly affect transcription of closely related genes. Consequently, chromosome fragmentation appears to be of crucial importance for surface antigen expression and evolution. Our data suggest that RNAi-mediated control of this genetic network by trans-acting RNAs allows rapid epigenetic adaptation by phenotypic variation in combination with long-term genetic adaptation by Darwinian evolution of antigen genes. PMID:25389173

  5. Fifteen Years (1993–2007 of Surface Freshwater Storage Variability in the Ganges-Brahmaputra River Basin Using Multi-Satellite Observations

    Directory of Open Access Journals (Sweden)

    Edward Salameh

    2017-03-01

    Full Text Available Surface water storage is a key component of the terrestrial hydrological and biogeochemical cycles that also plays a major role in water resources management. In this study, surface water storage (SWS variations are estimated at monthly time-scale over 15 years (1993–2007 using a hypsographic approach based on the combination of topographic information from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER and Hydrological Modeling and Analysis Platform (HyMAP-based Global Digital Elevation Models (GDEM and the Global Inundation Extent Multi-Satellite (GIEMS product in the Ganges-Brahmaputra basin. The monthly variations of the surface water storage are in good accordance with precipitation from Global Precipitation Climatology Project (GPCP, river discharges at the outlet of the Ganges and the Brahmaputra, and terrestrial water storage (TWS from the Gravity Recovery And Climate Experiment (GRACE, with correlations higher than 0.85. Surface water storage presents a strong seasonal signal (~496 km3 estimated by GIEMS/ASTER and ~378 km3 by GIEMS/HyMAPs, representing ~51% and ~41% respectively of the total water storage signal and it exhibits a large inter-annual variability with strong negative anomalies during the drought-like conditions of 1994 or strong positive anomalies such as in 1998. This new dataset of SWS is a new, highly valuable source of information for hydrological and climate modeling studies of the Ganges-Brahmaputra river basin.

  6. CLUMPING AND THE INTERPRETATION OF kpc-SCALE MAPS OF THE INTERSTELLAR MEDIUM: SMOOTH H I AND CLUMPY, VARIABLE H{sub 2} SURFACE DENSITY

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, Adam K. [National Radio Astronomy Observtory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Lee, Cheoljong [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Schruba, Andreas [California Institute for Technology, 1200 E California Blvd, Pasadena, CA 91125 (United States); Bolatto, Alberto [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Hughes, Annie; Sandstrom, Karin; Schinnerer, Eva; Walter, Fabian [Max Planck Institute fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Pety, Jerome [Institut de Radioastronomie Millimetrique, 300 Rue de la Piscine, F-38406 Saint Martin d' Heres (France)

    2013-05-20

    Many recent models consider the structure of individual interstellar medium (ISM) clouds as a way to explain observations of large parts of galaxies. To compare such models to observations, one must understand how to translate between surface densities observed averaging over large ({approx}kpc) scales and surface densities on the scale of individual clouds ({approx}pc scale), which are treated by models. We define a ''clumping factor'' that captures this translation as the ratio of the mass-weighted surface density, which is often the quantity of physical interest, to the area-weighted surface density, which is observed. We use high spatial resolution (sub-kpc) maps of CO and H I emission from nearby galaxies to measure the clumping factor of both atomic and molecular gas. The molecular and atomic ISM exhibit dramatically different degrees of clumping. As a result, the ratio H{sub 2}/H I measured at {approx}kpc resolution cannot be trivially interpreted as a cloud-scale ratio of surface densities. H I emission appears very smooth, with a clumping factor of only {approx}1.3. Based on the scarce and heterogeneous high-resolution data available, CO emission is far more clumped with a widely variable clumping factor, median {approx}7 for our heterogeneous data. Our measurements do not provide evidence for a universal mass-weighted surface density of molecular gas, but also cannot conclusively rule out such a scenario. We suggest that a more sophisticated treatment of molecular ISM structure, one informed by high spatial resolution CO maps, is needed to link cloud-scale models to kpc-scale observations of galaxies.

  7. Spatial and temporal variability in the Quality of Surface water in a semi-arid mediterranean region (river orontes- Lebanon)

    International Nuclear Information System (INIS)

    SLIM, K.; SAAD, Z.; KAZPARD, V.; EL SAMAD, O.; NASREDDINE, M.

    2004-01-01

    The Orontes River is an international river, with its headwaters in Lebanon, its middle section in Syria and its mouth in Turkey. Fresh surface waters were sampled monthly during the year 2000 and analyzed for major ions and for trace metals. Sea-salt aerosols in rainwater partially influence the major ion composition in the river. The concentration of major cations and anions fall within the range of the most common natural Concentration of major ion assemblages established for world river(MCNC), with a cation and anion dominance in the order of Ca > Mg > Na> K and HCO3 > SO4 > Cl, which tend to be predominantly influenced by chemical weathering of rocks and minerals in a semi-arid region. Ca and HCO3 are mostly derived from the dissolution of carbonate rocks. The sources of SO4 could be attributed to anhydrite minerals and to anthropogenic impact from fertilizers. Increases in nutrient concentrations are attributed mainly to the increasing influence of agricultural runoff. δ18 0/ δH plots shows that the data either fits the Mediterranean Meteoric Water Line(MMWL) or have elevated values that indicate evaporative isotope enrichment in a semi-arid climate. The correlation matrix for trace elements shows a high coefficient of correlation for Fe, Zn and Cu indicating that these elements could be controlled by the same chemistry in water. The bicarbonate-alkaline type of Orontes surface water contribute to the formation of trace metals-carbonate complexes such as FeCO3(aq) and ZnCO3 (aq). The good correlation between Pb, Cd and Cr reflects the effect of increasing urbanization in the catchments. (author)

  8. Investigating the spatio-temporal variability in groundwater and surface water interactions: a multi-technique approach

    Science.gov (United States)

    Unland, N. P.; Cartwright, I.; Andersen, M. S.; Rau, G. C.; Reed, J.; Gilfedder, B. S.; Atkinson, A. P.; Hofmann, H.

    2013-09-01

    The interaction between groundwater and surface water along the Tambo and Nicholson rivers, southeast Australia, was investigated using 222Rn, Cl, differential flow gauging, head gradients, electrical conductivity (EC) and temperature profiles. Head gradients, temperature profiles, Cl concentrations and 222Rn activities all indicate higher groundwater fluxes to the Tambo River in areas of increased topographic variation where the potential to form large groundwater-surface water gradients is greater. Groundwater discharge to the Tambo River calculated by Cl mass balance was significantly lower (1.48 × 104 to 1.41 × 103 m3 day-1) than discharge estimated by 222Rn mass balance (5.35 × 105 to 9.56 × 103 m3 day-1) and differential flow gauging (5.41 × 105 to 6.30 × 103 m3 day-1) due to bank return waters. While groundwater sampling from the bank of the Tambo River was intended to account for changes in groundwater chemistry associated with bank infiltration, variations in bank infiltration between sample sites remain unaccounted for, limiting the use of Cl as an effective tracer. Groundwater discharge to both the Tambo and Nicholson rivers was the highest under high-flow conditions in the days to weeks following significant rainfall, indicating that the rivers are well connected to a groundwater system that is responsive to rainfall. Groundwater constituted the lowest proportion of river discharge during times of increased rainfall that followed dry periods, while groundwater constituted the highest proportion of river discharge under baseflow conditions (21.4% of the Tambo in April 2010 and 18.9% of the Nicholson in September 2010).

  9. Selective interaction of heparin with the variable region 3 within surface glycoprotein of laboratory-adapted feline immunodeficiency virus.

    Directory of Open Access Journals (Sweden)

    Qiong-Ying Hu

    Full Text Available Heparan sulfate proteoglycans (HSPG can act as binding receptors for certain laboratory-adapted (TCA strains of feline immunodeficiency virus (FIV and human immunodeficiency virus (HIV. Heparin, a soluble heparin sulfate (HS, can inhibit TCA HIV and FIV entry mediated by HSPG interaction in vitro. In the present study, we further determined the selective interaction of heparin with the V3 loop of TCA of FIV. Our current results indicate that heparin selectively inhibits infection by TCA strains, but not for field isolates (FS. Heparin also specifically interferes with TCA surface glycoprotein (SU binding to CXCR4, by interactions with HSPG binding sites on the V3 loop of the FIV envelope protein. Peptides representing either the N- or C-terminal side of the V3 loop and containing HSPG binding sites were able to compete away the heparin block of TCA SU binding to CXCR4. Heparin does not interfere with the interaction of SU with anti-V3 antibodies that target the CXCR4 binding region or with the interaction between FS FIV and anti-V3 antibodies since FS SU has no HSPG binding sites within the HSPG binding region. Our data show that heparin blocks TCA FIV infection or entry not only through its competition of HSPG on the cell surface interaction with SU, but also by its interference with CXCR4 binding to SU. These studies aid in the design and development of heparin derivatives or analogues that can inhibit steps in virus infection and are informative regarding the HSPG/SU interaction.

  10. Specific proliferation rates of human osteoblasts on calcium phosphate surfaces with variable concentrations of α-TCP

    International Nuclear Information System (INIS)

    Santos, Euler A. dos; Farina, Marcos; Soares, Gloria A.

    2007-01-01

    Ideally, ceramics used in the repair of bone defects need to be resorbed and replaced by newly formed bone in vivo. Tricalcium phosphate (TCP) has been widely used in association with hydroxyapatite (HA) due to its higher resorption kinetics when compared with HA alone. The aim of our study was to quantitatively investigate the effect of α-tricalcium phosphate (α-TCP) on human osteoblasts' adhesion and proliferation. Ceramic samples with variable concentrations of α-TCP and HA were produced by the calcination of calcium-deficient and stoichiometric HA. Human osteoblasts were cultured on the materials in three distinct experiments with different concentrations of cells. Numerical evaluation of cellular growth along time in culture was performed for each condition. The quantity of cells seeded onto the ceramics seems to influence the osteoblast behavior once proliferation was lower when more cells were seeded onto the samples. However, a smaller content of α-TCP in relation to that of HA did not significantly modify the specific proliferation rates of the osteoblasts. Only after a long time in culture, the increasing of the α-TCP content seems to change the cells' behavior

  11. Extended Enterprise performance Management

    NARCIS (Netherlands)

    Bobbink, Maria Lammerdina; Hartmann, Andreas

    2014-01-01

    The allegiance of partnering organisations and their employees to an Extended Enterprise performance is its proverbial sword of Damocles. Literature on Extended Enterprises focuses on collaboration, inter-organizational integration and learning to avoid diminishing or missing allegiance becoming an

  12. Spatial and Temporal Variability of CO2 and CH4 Concentrations in the Atmospheric Surface Layer over West Siberia

    Science.gov (United States)

    Belan, Boris D.; Machida, Toshinobu; Sasakawa, Motoki; Davydov, Denis K.; Fofonov, Alexander V.; Krasnov, Oleg A.; Maksyutov, Shamil; Arshinov, Mikhail Yu.

    2015-04-01

    The investigation of greenhouse gas behavior in the atmosphere plays a key role in predicting the global changes of Earth's climate. In this connection, of particular importance is the study of the distribution of sources/sinks of trace gases in the atmospheric surface layer over the different regions of the globe. In order to fill a gap in the data on greenhouse gas concentrations in Russia, National Institute for Environmental Studies (NIES, Japan) and Institute of Atmospheric Optics (IAO SB RAS, Russia) established a network for GHG monitoring (JR-STATION, Japan-Russia Siberian Tall Tower Inland Observation Network). Gas analyzers and meteorological sensors were mounted at radio relay towers located in different regions of West Siberia. The checking equipment was placed in containers at the tower base. In the containers, the climatic parameters optimal for gas analyzer operation were maintained. The work on the network development started in 2001. Since at each of the sites the measurement duration could be different, in this paper we present the data of the greenhouse gas monitoring for eight sites which give the primary idea on the spatial distribution and temporal dynamics of CO2 and CH4 in the atmospheric surface layer over West Siberia. The analysis of the data showed that the average increase in concentration of carbon dioxide by results of our measurements in this territory increases within 1.95 - 2.53 ppm/year, depending on the area. The analysis of long-term data testifies about existence of growth of concentration of methane within 3.2 - 7.2 ppb / year. The presence of a distributed network of the sites operating in the monitoring regime makes it possible not only to investigate the temporal dynamics of CO2 and CH4 at each site and to determine the spatial differences between the concentrations by comparing the data, but also to plot the distribution charts for different moments of time. This work was supported by the Global Environment Research

  13. Perspectives on extended Deterrence

    International Nuclear Information System (INIS)

    Tertrais, Bruno; Yost, David S.; Bunn, Elaine; Lee, Seok-soo; Levite, Ariel e.; Russell, James A.; Hokayem, Emile; Kibaroglu, Mustafa; Schulte, Paul; Thraenert, Oliver; Kulesa, Lukasz

    2010-05-01

    In November 2009, the Foundation for Strategic Research (Fondation pour la recherche strategique, FRS) convened a workshop on 'The Future of extended Deterrence', which included the participation of some of the best experts of this topic, from the United States, Europe, the Middle East and East Asia, as well as French and NATO officials. This document brings together the papers prepared for this seminar. Several of them were updated after the publication in April 2010 of the US Nuclear Posture Review. The seminar was organized with the support of the French Atomic energy Commission (Commissariat a l'energie atomique - CEA). Content: 1 - The future of extended deterrence: a brainstorming paper (Bruno Tertrais); 2 - US extended deterrence in NATO and North-East Asia (David S. Yost); 3 - The future of US extended deterrence (Elaine Bunn); 4 - The future of extended deterrence: a South Korean perspective (Seok-soo Lee); 5 - Reflections on extended deterrence in the Middle East (Ariel e. Levite); 6 - extended deterrence, security guarantees and nuclear weapons: US strategic and policy conundrums in the Gulf (James A. Russell); 7 - extended deterrence in the Gulf: a bridge too far? (Emile Hokayem); 8 - The future of extended deterrence: the case of Turkey (Mustafa Kibaroglu); 9 - The future of extended deterrence: a UK view (Paul Schulte); 10 - NATO and extended deterrence (Oliver Thraenert); 11 - extended deterrence and assurance in Central Europe (Lukasz Kulesa)

  14. Temporal variability of surface runoff due to cropping systems in cultivated catchment areas: Use of the DIAR model for the assessment of environmental public policies in the Pays de Caux (France).

    Science.gov (United States)

    Martin, P; Joannon, A; Piskiewicz, N

    2010-01-01

    This article proposes the use of a new model, DIAR (Diagnostic Agronomique du Ruissellement, or Agronomic Assessment of Runoff), for the prediction of the timing of the risk of runoff. DIAR is dedicated to loamy soils which are very sensitive to surface crusting, leading to runoff, soil erosion and muddy flows. The approach is proposed for the north-western European loess belt regions where muddy flows severely impact human activities. The likelihood of runoff is assessed from the sequence of soil surface states generated by cultivation practices. DIAR is based on the calculation of curve number values, for each stage of the soil-surface-state sequence, for calculating runoff for each of these stages. In this study, DIAR is applied to a catchment of 912 ha, cultivated by 26 farmers in the Pays de Caux (Normandy, France) where infrastructures located at the outlet have been damaged several times by muddy flows. Local public authorities involved in reducing muddy flows are eager to limit the agricultural upstream runoff by extending the planting of mustard as a winter cover crop. We tested the efficiency of such a policy on the reduction of the mean runoff. We also tested the year-to-year variability of this efficiency using the acreages of four successive years (1999-2000 to 2002-2003). Finally, the cost-efficiency of the policy was also considered. Though we used the same weather scenario, the initial situation (without much mustard cover) showed a wide year-to-year variation in the total runoff. This variation can be associated with the structure of the farms that cultivate the catchment (Utilised Agricultural Area (UAA) of each farm and percentage of this UAA inside the catchment). Our results showed that the widespread planting of winter cover crops could reduce the runoff by 10-20% compared with the initial situation (depending on the year), and also reduce the year-to-year variability of runoff. For each of the 4 tested years, the cost of the infiltrated m(3

  15. Natural convection of nanofluid in a wavy cavity in the presence of magnetic field on variable heat surface temperature

    Energy Technology Data Exchange (ETDEWEB)

    Javaherdeh, Korosh; Moslemi, Mehdi; Shahbazi, Mona [University of Guilan, Rasht (Iran, Islamic Republic of)

    2017-04-15

    A numerical analysis has been performed to investigate the laminar natural convection heat characteristics in a wavy cavity filled with CuO/water nanofluid. One of the sinusoidal walls (BC) is at the volatile high temperature and the opposite wavy surface is at a stable low temperature and the two other walls are considered flat and insulated while the uniform magnetic field is considered. Performing the analysis, the governing equations are given in terms of the stream function-vorticity formulation. In order to solve the nondimensionalized equations, discretizing with second-order accurate central difference method is performed then the successive under relaxation method with appropriate boundary conditions is considered. To validate the numerical model, various comparisons with previously published studies have been conducted and the results are in a good agreement. The main objective is to survey the effects of the Rayleigh number, Hartmann number, and nanoparticles volume fraction on the fluid flow and heat transfer characteristics. The results are illustrated in contours of stream function, constant temperature, and Nusselt number. The results show that the presence of the magnetic field the local Nusselt number decreases at the hot wall. Moreover, the enhancement in the heat transfer performance increases with an increasing nanoparticle concentration. However, for all values of Rayleigh number, the presence of nanoparticles leads to significant enhancement in heat transfer and the increase of Rayleigh number causes the heat transfer mechanism to change from conduction to convection.

  16. Review of the margins for ASME code fatigue design curve - effects of surface roughness and material variability

    International Nuclear Information System (INIS)

    Chopra, O. K.; Shack, W. J.

    2003-01-01

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. The Code specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life ((var e psilon)-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of the existing fatigue (var e psilon)-N data for carbon and low-alloy steels and wrought and cast austenitic SSs to define the effects of key material, loading, and environmental parameters on the fatigue lives of the steels. Experimental data are presented on the effects of surface roughness on the fatigue life of these steels in air and LWR environments. Statistical models are presented for estimating the fatigue (var e psilon)-N curves as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are discussed. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue evaluations. A critical review of the margins for ASME Code fatigue design curves is presented

  17. Review of the margins for ASME code fatigue design curve - effects of surface roughness and material variability.

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O. K.; Shack, W. J.; Energy Technology

    2003-10-03

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. The Code specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life ({var_epsilon}-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of the existing fatigue {var_epsilon}-N data for carbon and low-alloy steels and wrought and cast austenitic SSs to define the effects of key material, loading, and environmental parameters on the fatigue lives of the steels. Experimental data are presented on the effects of surface roughness on the fatigue life of these steels in air and LWR environments. Statistical models are presented for estimating the fatigue {var_epsilon}-N curves as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are discussed. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue evaluations. A critical review of the margins for ASME Code fatigue design curves is presented.

  18. Use of agricultural statistics to verify the interannual variability in land surface models: a case study over France with ISBA-A-gs

    Directory of Open Access Journals (Sweden)

    J.-C. Calvet

    2012-01-01

    Full Text Available In order to verify the interannual variability of the above-ground biomass of herbaceous vegetation simulated by the ISBA-A-gs land surface model, within the SURFEX modelling platform, French agricultural statistics for C3 crops and grasslands were compared with the simulations for the 1994–2008 period. While excellent correlations are obtained for grasslands, representing the interannual variability of crops is more difficult. It is shown that, the Maximum Available soil Water Capacity (MaxAWC has a large influence on the correlation between the model and the agricultural statistics. In particular, high values of MaxAWC tend to reduce the impact of the climate interannual variability on the simulated biomass. Also, high values of MaxAWC allow the simulation of a negative trend in biomass production, in relation to a marked warming trend, of about 0.12 Kyr−1 on average, affecting the daily maximum air temperature during the growing period (April–June. This trend is particularly acute in Northern France. The estimates of MaxAWC for C3 crops and grasslands, currently used in SURFEX, are about 129 mm and do not vary much. Therefore, more accurate grid-cell values of this parameter are needed.

  19. A statistical-dynamical scheme for reconstructing ocean forcing in the Atlantic. Part I: weather regimes as predictors for ocean surface variables

    Energy Technology Data Exchange (ETDEWEB)

    Cassou, Christophe; Minvielle, Marie; Terray, Laurent [CERFACS/CNRS, Climate Modelling and Global Change Team, Toulouse (France); Perigaud, Claire [JPL-NASA, Ocean Science Element, Pasadena, CA (United States)

    2011-01-15

    The links between the observed variability of the surface ocean variables estimated from reanalysis and the overlying atmosphere decomposed in classes of large-scale atmospheric circulation via clustering are investigated over the Atlantic from 1958 to 2002. Daily 500 hPa geopotential height and 1,000 hPa wind anomaly maps are classified following a weather-typing approach to describe the North Atlantic and tropical Atlantic atmospheric dynamics, respectively. The algorithm yields patterns that correspond in the extratropics to the well-known North Atlantic-Europe weather regimes (NAE-WR) accounting for the barotropic dynamics, and in the tropics to wind classes (T-WC) representing the alteration of the trades. 10-m wind and 2-m temperature (T2) anomaly composites derived from regime/wind class occurrence are indicative of strong relationships between daily large-scale atmospheric circulation and ocean surface over the entire Atlantic basin. High temporal correlation values are obtained basin-wide at low frequency between the observed fields and their reconstruction by multiple linear regressions with the frequencies of occurrence of both NAE-WR and T-WC used as sole predictors. Additional multiple linear regressions also emphasize the importance of accounting for the strength of the daily anomalous atmospheric circulation estimated by the combined distances to all regimes centroids in order to reproduce the daily to interannual variability of the Atlantic ocean. We show that for most of the North Atlantic basin the occurrence of NAE-WR generally sets the sign of the ocean surface anomaly for a given day, and that the inter-regime distances are valuable predictors for the magnitude of that anomaly. Finally, we provide evidence that a large fraction of the low-frequency trends in the Atlantic observed at the surface over the last 50 years can be traced back, except for T2, to changes in occurrence of tropical and extratropical weather classes. All together, our

  20. CMIP5 land surface models systematically underestimate inter-annual variability of net ecosystem exchange in semi-arid southwestern North America.

    Science.gov (United States)

    MacBean, N.; Scott, R. L.; Biederman, J. A.; Vuichard, N.; Hudson, A.; Barnes, M.; Fox, A. M.; Smith, W. K.; Peylin, P. P.; Maignan, F.; Moore, D. J.

    2017-12-01

    Recent studies based on analysis of atmospheric CO2 inversions, satellite data and terrestrial biosphere model simulations have suggested that semi-arid ecosystems play a dominant role in the interannual variability and long-term trend in the global carbon sink. These studies have largely cited the response of vegetation activity to changing moisture availability as the primary mechanism of variability. However, some land surface models (LSMs) used in these studies have performed poorly in comparison to satellite-based observations of vegetation dynamics in semi-arid regions. Further analysis is therefore needed to ensure semi-arid carbon cycle processes are well represented in global scale LSMs before we can fully establish their contribution to the global carbon cycle. In this study, we evaluated annual net ecosystem exchange (NEE) simulated by CMIP5 land surface models using observations from 20 Ameriflux sites across semi-arid southwestern North America. We found that CMIP5 models systematically underestimate the magnitude and sign of NEE inter-annual variability; therefore, the true role of semi-arid regions in the global carbon cycle may be even more important than previously thought. To diagnose the factors responsible for this bias, we used the ORCHIDEE LSM to test different climate forcing data, prescribed vegetation fractions and model structures. Climate and prescribed vegetation do contribute to uncertainty in annual NEE simulations, but the bias is primarily caused by incorrect timing and magnitude of peak gross carbon fluxes. Modifications to the hydrology scheme improved simulations of soil moisture in comparison to data. This in turn improved the seasonal cycle of carbon uptake due to a more realistic limitation on photosynthesis during water stress. However, the peak fluxes are still too low, and phenology is poorly represented for desert shrubs and grasses. We provide suggestions on model developments needed to tackle these issues in the future.

  1. Asian droughts in the last millennium: a search for robust impacts of Pacific Ocean surface temperature variabilities

    Science.gov (United States)

    Yu, Entao; King, Martin P.; Sobolowski, Stefan; Otterå, Odd Helge; Gao, Yongqi

    2018-06-01

    This study investigates the robustness of hydroclimate impacts in Asia due to major drivers of climate variability in the Pacific Ocean, namely the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Composite analyses are carried out on a tree ring-based Palmer Drought Severity Index as well as on a long coupled global climate model control experiment. El Niño (La Niña) has a robust impact on wet (dry) conditions in West Asia and dry (wet) conditions in South Asia. For the PDO, impacts are found throughout the Asia domain. However, identifying the robust signals due to PDO from these analyses is more challenging due to the limited lengths of the data. Results indicate that West Asia (South and Southeast Asia) experiences wet (dry) conditions during periods of positive PDO. For East Asia, there is indication that positive (negative) PDO is associated with wet (dry) conditions around and southward of 30°N and dry (wet) conditions north of this latitude. This result is consistent with the current understanding of the role of PDO in the "southern-flood northern-drought" phenomenon in China. We suggest that specific extreme events or periods have regional impacts with strong intensities that cannot be fully explained through the composite analysis of ENSO, PDO, or any combination thereof. Two such examples are shown to illustrate this: the Strange Parallel Drought (1756-1768 CE) and the Great Drought (1876-1878 CE). Additionally, during these climate events, ENSO and PDO can be in phases which are not consistent with the required phases of these drivers that explain the concurrent drought and pluvial conditions in Asia. Therefore, not all historical drought and pluvial events in Northeast Asia and northern China can be related back to ENSO or PDO. Finally, we also examine the dynamical characteristics of the reported hydroclimatic impacts in the global climate model experiment. There is moisture transport into (out of) regions that exhibit

  2. Sensitivity of Photosynthetic Gas Exchange and Growth of Lodgepole Pine to Climate Variability Depends on the Age of Pleistocene Glacial Surfaces

    Science.gov (United States)

    Osborn, B.; Chapple, W.; Ewers, B. E.; Williams, D. G.

    2014-12-01

    The interaction between soil conditions and climate variability plays a central role in the ecohydrological functions of montane conifer forests. Although soil moisture availability to trees is largely dependent on climate, the depth and texture of soil exerts a key secondary influence. Multiple Pleistocene glacial events have shaped the landscape of the central Rocky Mountains creating a patchwork of soils differing in age and textural classification. This mosaic of soil conditions impacts hydrological properties, and montane conifer forests potentially respond to climate variability quite differently depending on the age of glacial till and soil development. We hypothesized that the age of glacial till and associated soil textural changes exert strong control on growth and photosynthetic gas exchange of lodgepole pine. We examined physiological and growth responses of lodgepole pine to interannual variation in maximum annual snow water equivalence (SWEmax) of montane snowpack and growing season air temperature (Tair) and vapor pressure deficit (VPD) across a chronosequence of Pleistocene glacial tills ranging in age from 700k to 12k years. Soil textural differences across the glacial tills illustrate the varying degrees of weathering with the most well developed soils with highest clay content on the oldest till surfaces. We show that sensitivity of growth and carbon isotope discrimination, an integrated measure of canopy gas exchange properties, to interannual variation SWEmax , Tair and VPD is greatest on young till surfaces, whereas trees on old glacial tills with well-developed soils are mostly insensitive to these interannual climate fluctuations. Tree-ring widths were most sensitive to changes in SWEmax on young glacial tills (p < 0.01), and less sensitive on the oldest till (p < 0.05). Tair correlates strongly with δ13C values on the oldest and youngest tills sites, but shows no significant relationship on the middle aged glacial till. It is clear that

  3. The influence of sea surface temperature anomalies on low-frequency variability of the North Atlantic Oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Manganello, Julia V. [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States)

    2008-05-15

    The influence of sea surface temperature anomalies (SSTA) on multi-year persistence of the North Atlantic Oscillation (NAO) during the second half of the twentieth century is investigated using the Center for Ocean-Land-Atmosphere Studies (COLA) Atmospheric GCM (AGCM) with an emphasis on isolating the geographic location of the SSTA that produce this influence. The present study focuses on calculating the atmospheric response to the SSTA averaged over 1988-1995 (1961-1968) corresponding to the observed period of strong persistence of the positive (negative) phase of the decadal NAO. The model response to the global 1988-1995 average SSTA shows a statistically significant large-scale pattern characteristic of the positive phase of the NAO. Forcing with the global 1961-1968 average SSTA generates a NAO of the opposite polarity compared to observations. However, all large-scale features both in the model and observations during this period are weaker in magnitude and less significant compared to 1988-1995. Additional idealized experiments show that over the northern center of the NAO the non-linear component of the forced response appears to be quite important and acts to enhance the positive NAO signal. On the other hand, over the southern center where the model response is the strongest, it is also essentially linear. The 1988-1995 average SSTA restricted to the western tropical Pacific region produce a positive NAO remarkably similar in structure but stronger in magnitude than the model response to the global and tropical Indo-Pacific 1988-1995 forcing. A 200-hPa geopotential height response in these experiments shows a positive anomaly over the southern center of the NAO embedded in the Rossby wave trains propagating from the western tropical Pacific. Indian Ocean SSTA lead to much weaker positive NAO primarily through the effect on its northern center. SST forcing confined to the North Atlantic north of equator does not produce a response statistically different

  4. Effects of the Distance from a Diffusive Surface on the Objective and Perceptual Evaluation of the Sound Field in a Small Simulated Variable-Acoustics Hall

    Directory of Open Access Journals (Sweden)

    Louena Shtrepi

    2017-02-01

    Full Text Available Simulations of the acoustic effects that diffusive surfaces have on the objective acoustic parameters and on sound perception have not yet been fully understood. To this end, acoustic simulations have been performed in Odeon in the model of a variable-acoustic concert hall. This paper is presented as a follow-up study to a previous paper that dealt with in-field measurements only. As in measurements, a diffusive and a reflective condition of one of the lateral walls have been considered in the room models. Two modeling alternatives of the diffusive condition, that is, (a a flat surface with high scattering coefficient applied; and (b a triangular relief modeled including edge diffraction, have been investigated. Objective acoustic parameters, such as early decay time (EDT, reverberation time (T30, clarity (C80, definition (D50, and interaural cross correlation (IACC, have been compared between the two conditions. Moreover, an auditory experiment has been performed to determine the maximum distance from a diffusive surface at which the simulated acoustic scattering effects are still audible. Although the simulated objective results showed a good match with measured values, the subjective results showed that the differences between the diffuse and reflective conditions become significant when model (b is used.

  5. Inter-annual variability of surface ozone at coastal (Dumont d'Urville, 2004–2014 and inland (Concordia, 2007–2014 sites in East Antarctica

    Directory of Open Access Journals (Sweden)

    M. Legrand

    2016-07-01

    Full Text Available Surface ozone has been measured since 2004 at the coastal East Antarctic site of Dumont d'Urville (DDU, and since 2007 at the Concordia station located on the high East Antarctic plateau. This paper discusses long-term changes, seasonal and diurnal cycles, as well as inter-annual summer variability observed at these two East Antarctic sites. At Concordia, near-surface ozone data were complemented by balloon soundings and compared to similar measurements done at the South Pole. The DDU record is compared to those obtained at the coastal site of Syowa, also located in East Antarctica, as well as the coastal sites of Neumayer and Halley, both located on the coast of the Weddell Sea in West Antarctica. Surface ozone mixing ratios exhibit very similar seasonal cycles at Concordia and the South Pole. However, in summer the diurnal cycle of ozone is different at the two sites with a drop of ozone in the afternoon at Concordia but not at the South Pole. The vertical distribution of ozone above the snow surface also differs. When present, the ozone-rich layer located near the ground is better mixed and deeper at Concordia (up to 400 m than at the South Pole during sunlight hours. These differences are related to different solar radiation and wind regimes encountered at these two inland sites. DDU appears to be the coastal site where the impact of the late winter/spring bromine chemistry is the weakest, but where the impact of elevated ozone levels caused by NOx snow emissions from the high Antarctic plateau is the highest. The highest impact of the bromine chemistry is seen at Halley and Neumayer, and to a lesser extent at Syowa. These three sites are only weakly impacted by the NOx chemistry and the net ozone production occurring on the high Antarctic plateau. The differences in late winter/spring are attributed to the abundance of sea ice offshore from the sites, whereas those in summer are related to the topography of East Antarctica that promotes

  6. Modeling and optimization of fermentation variables for enhanced production of lactase by isolated Bacillus subtilis strain VUVD001 using artificial neural networking and response surface methodology.

    Science.gov (United States)

    Venkateswarulu, T C; Prabhakar, K Vidya; Kumar, R Bharath; Krupanidhi, S

    2017-07-01

    Modeling and optimization were performed to enhance production of lactase through submerged fermentation by Bacillus subtilis VUVD001 using artificial neural networks (ANN) and response surface methodology (RSM). The effect of process parameters namely temperature (°C), pH, and incubation time (h) and their combinational interactions on production was studied in shake flask culture by Box-Behnken design. The model was validated by conducting an experiment at optimized process variables which gave the maximum lactase activity of 91.32 U/ml. Compared to traditional activity, 3.48-folds improved production was obtained after RSM optimization. This study clearly shows that both RSM and ANN models provided desired predictions. However, compared with RSM (R 2  = 0.9496), the ANN model (R 2  = 0.99456) gave a better prediction for the production of lactase.

  7. A first look at the ACER-SST dataset: Mapping the spatio-temporal variability of sea-surface temperatures in the last Glacial and the Holocene

    Science.gov (United States)

    Rehfeld, Kira; Laepple, Thomas; Bassinot, Franck; Daniau, Anne-Laure; Desprat, Stéphanie; Kim, Jung-Hyun; Fernanda Sánchez-Goñi, Maria; Harrison, Sandy

    2016-04-01

    Climate in the last Glacial was characterized by abrupt and large-scale changes around cold Heinrich-Events and warm Dansgaard-Oeschger excursions in the Northern high latitudes. The global repercussions of these periods of rapid dynamics are, to date, unconstrained. Here, we present a first statistical analysis of the global multi-proxy ACER (Abrupt Climate Changes and Environmental Responses) sea surface temperature dataset, spanning the last 80 thousand years, to investigate the spatial footprints of glacial climate dynamics. In a first step we evaluate the spatial and temporal variability throughout the Glacial period, and contrast them with that during the Holocene. In a second step we investigate to which extent a temporal synchroneity of extreme events during the Glacial is detectable in the proxy records, and analyze the reversibility of Glacial dynamics.

  8. Variability of water content useful in surface along a rainfall gradient Mediterranean; Variabilidad de la disposibilidad hidrica superficial para la vegetacion a lo largo de un gradiente pluviometrico

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Sinoga, J. D.; Martinez-Murillo, J. F.; Gabarron-Galeote, M. A.

    2009-07-01

    A climatic gradient was defined in South of spain with a great decreased of rainfall from West to East (>1,000 mm), which produces changes in vegetation and hydric resources. this study was carried out in five hill slopes under different climatic conditions and their aims were to analyze: the variability of available water along the gradient since 2002 to 2006, the key factors of it and the influence on the vegetal cover. Results showed that clay content had a great influence in the surface available water for plants, which did not decrease in the deerfield sites, where the amount of days with hydric deficient was lower. Relationships between vegetation and soil water were stronger in the more humid field sites, where existed a feedback between both properties. (Author) 4 refs.

  9. Extended icosahedral structures

    CERN Document Server

    Jaric, Marko V

    1989-01-01

    Extended Icosahedral Structures discusses the concepts about crystal structures with extended icosahedral symmetry. This book is organized into six chapters that focus on actual modeling of extended icosahedral crystal structures. This text first presents a tiling approach to the modeling of icosahedral quasiperiodic crystals. It then describes the models for icosahedral alloys based on random connections between icosahedral units, with particular emphasis on diffraction properties. Other chapters examine the glassy structures with only icosahedral orientational order and the extent of tra

  10. Landsat classification of surface-water presence during multiple years to assess response of playa wetlands to climatic variability across the Great Plains Landscape Conservation Cooperative region

    Science.gov (United States)

    Manier, Daniel J.; Rover, Jennifer R.

    2018-02-15

    To improve understanding of the distribution of ecologically important, ephemeral wetland habitats across the Great Plains, the occurrence and distribution of surface water in playa wetland complexes were documented for four different years across the Great Plains Landscape Conservation Cooperative (GPLCC) region. This information is important because it informs land and wildlife managers about the timing and location of habitat availability. Data with an accurate timestamp that indicate the presence of water, the percent of the area inundated with water, and the spatial distribution of playa wetlands with water are needed for a host of resource inventory, monitoring, and research applications. For example, the distribution of inundated wetlands forms the spatial pattern of available habitat for resident shorebirds and water birds, stop-over habitats for migratory birds, connectivity and clustering of wetland habitats, and surface waters that recharge the Ogallala aquifer; there is considerable variability in the distribution of playa wetlands holding water through time. Documentation of these spatially and temporally intricate processes, here, provides data required to assess connections between inundation and multiple environmental drivers, such as climate, land use, soil, and topography. Climate drivers are understood to interact with land cover, land use and soil attributes in determining the amount of water that flows overland into playa wetlands. Results indicated significant spatial variability represented by differences in the percent of playas inundated among States within the GPLCC. Further, analysis-of-variance comparison of differences in inundation between years showed significant differences in all cases. Although some connections with seasonal moisture patterns may be observed, the complex spatial-temporal gradients of precipitation, temperature, soils, and land use need to be combined as covariates in multivariate models to effectively account for

  11. Spatial variability analysis of combining the water quality and groundwater flow model to plan groundwater and surface water management in the Pingtung plain

    Science.gov (United States)

    Chen, Ching-Fang; Chen, Jui-Sheng; Jang, Cheng-Shin

    2014-05-01

    As a result of rapid economic growth in the Pingtung Plain, the use of groundwater resources has changed dramatically. The groundwater is quite rich in the Pingtung plain and the most important water sources. During the several decades, a substantial amount of groundwater has been pumped for the drinking, irrigation and aquaculture water supplies. However, because the sustainable use concept of groundwater resources is lack, excessive pumping of groundwater causes the occurrence of serious land subsidence and sea water intrusion. Thus, the management and conservation of groundwater resources in the Pingtung plain are considerably critical. This study aims to assess the conjunct use effect of groundwater and surface water in the Pingtung plain on recharge by reducing the amount of groundwater extraction. The groundwater quality variability and groundwater flow models are combined to spatially analyze potential zones of groundwater used for multi-purpose in the Pingtung Plain. First, multivariate indicator kriging (MVIK) is used to analyze spatial variability of groundwater quality based on drinking, aquaculture and irrigation water quality standards, and probabilistically delineate suitable zones in the study area. Then, the groundwater flow model, Processing MODFLOW (PMWIN), is adopted to simulate groundwater flow. The groundwater flow model must be conducted by the calibration and verification processes, and the regional groundwater recovery is discussed when specified water rights are replaced by surface water in the Pingtung plain. Finally, the most suitable zones of reducing groundwater use are determined for multi-purpose according to combining groundwater quality and quantity. The study results can establish a sound and low-impact management plan of groundwater resources utilization for the multi-purpose groundwater use, and prevent decreasing ground water tables, and the occurrence of land subsidence and sea water intrusion in the Pingtung plain.

  12. Extending Database Integration Technology

    National Research Council Canada - National Science Library

    Buneman, Peter

    1999-01-01

    Formal approaches to the semantics of databases and database languages can have immediate and practical consequences in extending database integration technologies to include a vastly greater range...

  13. Long-Term Trends, Variability and Extremes of In Situ Sea Surface Temperature Measured Along the Eastern Adriatic Coast and its Relationship to Hemispheric Processes

    Science.gov (United States)

    Grbec, Branka; Matić, Frano; Beg Paklar, Gordana; Morović, Mira; Popović, Ružica; Vilibić, Ivica

    2018-02-01

    This paper examines long-term series of in situ sea surface temperature (SST) data measured at nine coastal and one open sea stations along the eastern Adriatic Sea for the period 1959-2015. Monthly and yearly averages were used to document SST trends and variability, while clustering and connections to hemispheric indices were achieved by applying the Principal Component Analysis (PCA) and Self-Organizing Maps (SOM) method. Both PCA and SOM revealed the dominance of temporal changes with respect to the effects of spatial differences in SST anomalies, indicating the prevalence of hemispheric processes over local dynamics, such as bora wind spatial inhomogeneity. SST extremes were connected with blocking atmospheric patterns. A substantial warming between 1979 and 2015, in total exceeding 1 °C, was preceded by a period with a negative SST trend, implying strong multidecadal variability in the Adriatic. The strongest connection was found between yearly SST and the East Atlantic (EA) pattern, while North Atlantic Oscillation (NAO) and East Atlantic/West Russia (EAWR) patterns were found to also affect February SST values. Quantification of the Adriatic SST and their connection to hemispheric indices allow for more precise projections of future SST, considered to be rather important for Adriatic thermohaline circulation, biogeochemistry and fisheries, and sensitive to ongoing climate change.

  14. A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for the Surface of Mars: An Instrument for the Planetary Science Community

    Science.gov (United States)

    Edmunson, J.; Gaskin, J. A.; Danilatos, G.; Doloboff, I. J.; Effinger, M. R.; Harvey, R. P.; Jerman, G. A.; Klein-Schoder, R.; Mackie, W.; Magera, B.; hide

    2016-01-01

    The Miniaturized Variable Pressure Scanning Electron Microscope(MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Science (ROSES), will build upon previous miniaturized SEM designs for lunar and International Space Station (ISS) applications and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. By the end of the PICASSO work, a prototype of the primary proof-of-concept components (i.e., the electron gun, focusing optics and scanning system)will be assembled and preliminary testing in a Mars analog chamber at the Jet Propulsion Laboratory will be completed to partially fulfill Technology Readiness Level to 5 requirements for those components. The team plans to have Secondary Electron Imaging(SEI), Backscattered Electron (BSE) detection, and Energy Dispersive Spectroscopy (EDS) capabilities through the MVP-SEM.

  15. Assessing the impact of local meteorological variables on surface ozone in Hong Kong during 2000-2015 using quantile and multiple line regression models

    Science.gov (United States)

    Zhao, Wei; Fan, Shaojia; Guo, Hai; Gao, Bo; Sun, Jiaren; Chen, Laiguo

    2016-11-01

    The quantile regression (QR) method has been increasingly introduced to atmospheric environmental studies to explore the non-linear relationship between local meteorological conditions and ozone mixing ratios. In this study, we applied QR for the first time, together with multiple linear regression (MLR), to analyze the dominant meteorological parameters influencing the mean, 10th percentile, 90th percentile and 99th percentile of maximum daily 8-h average (MDA8) ozone concentrations in 2000-2015 in Hong Kong. The dominance analysis (DA) was used to assess the relative importance of meteorological variables in the regression models. Results showed that the MLR models worked better at suburban and rural sites than at urban sites, and worked better in winter than in summer. QR models performed better in summer for 99th and 90th percentiles and performed better in autumn and winter for 10th percentile. And QR models also performed better in suburban and rural areas for 10th percentile. The top 3 dominant variables associated with MDA8 ozone concentrations, changing with seasons and regions, were frequently associated with the six meteorological parameters: boundary layer height, humidity, wind direction, surface solar radiation, total cloud cover and sea level pressure. Temperature rarely became a significant variable in any season, which could partly explain the peak of monthly average ozone concentrations in October in Hong Kong. And we found the effect of solar radiation would be enhanced during extremely ozone pollution episodes (i.e., the 99th percentile). Finally, meteorological effects on MDA8 ozone had no significant changes before and after the 2010 Asian Games.

  16. Temporal variability of exchange between groundwater and surface water based on high-frequency direct measurements of seepage at the sediment-water interface

    Science.gov (United States)

    Rosenberry, Donald O.; Sheibley, Rich W.; Cox, Stephen E.; Simonds, Frederic W.; Naftz, David L.

    2013-01-01

    Seepage at the sediment-water interface in several lakes, a large river, and an estuary exhibits substantial temporal variability when measured with temporal resolution of 1 min or less. Already substantial seepage rates changed by 7% and 16% in response to relatively small rain events at two lakes in the northeastern USA, but did not change in response to two larger rain events at a lake in Minnesota. However, seepage at that same Minnesota lake changed by 10% each day in response to withdrawals from evapotranspiration. Seepage increased by more than an order of magnitude when a seiche occurred in the Great Salt Lake, Utah. Near the head of a fjord in Puget Sound, Washington, seepage in the intertidal zone varied greatly from −115 to +217 cm d−1 in response to advancing and retreating tides when the time-averaged seepage was upward at +43 cm d−1. At all locations, seepage variability increased by one to several orders of magnitude in response to wind and associated waves. Net seepage remained unchanged by wind unless wind also induced a lake seiche. These examples from sites distributed across a broad geographic region indicate that temporal variability in seepage in response to common hydrological events is much larger than previously realized. At most locations, seepage responded within minutes to changes in surface-water stage and within minutes to hours to groundwater recharge associated with rainfall. Likely implications of this dynamism include effects on water residence time, geochemical transformations, and ecological conditions at and near the sediment-water interface.

  17. Late Neogene Orbitally-Forced Sea Surface Temperature Variability in the Eastern Equatorial Pacific as Measured by Uk'37 and TEX86

    Science.gov (United States)

    Lawrence, K. T.; Pearson, A.; Castañeda, I. S.; Peterson, L.

    2017-12-01

    Key features of late Neogene climate remain uncertain due to conflicting records derived from different sea surface temperature (SST) proxies. To resolve these disputes, it is necessary to explore both the consistencies and differences between paleotemperature estimates from critical oceanographic regimes. Here, we report orbital-scale climate variability at ODP Site 846 in the Eastern Equatorial Pacific (EEP) in the interval from 5-6 Ma using alkenone and TEX86 temperature estimates. Results from both proxies are very similar in their secular trends and magnitude of long-term temperature change; and spectral analysis demonstrates that the records are coherent and in-phase or nearly in-phase in both the obliquity and precession bands. However, we find that the temperatures reconstructed by TEX86 are consistently offset towards colder values by 2ºC with orbital-scale variations approximately twice the amplitude of the Uk'37 derived estimates. Both temperature records are antiphased - i.e. "colder" - at higher sediment alkenone concentrations, a qualitative indicator of increased glacial productivity. Temperature differences between the proxies are accentuated during glacial intervals in contrasts to modern observations of EEP surface and subsurface temperatures, which show that thermocline temperatures are fairly stable, and thus by analogy, glacial cooling and/or enhanced upwelling should have reduced rather than accentuated temperature gradients in the upper water column. Therefore, arguments that Uk'37 corresponds to temperature variability in the surface, while TEX86 responds to the subsurface, may be too simplistic. Instead, it appears generally true that high-productivity environments, including the EEP, tend to have negative TEX86 anomalies. This may reflect a dual dependence of TEX86 records on both water column temperature and local productivity. Overall, our data suggest that in the EEP and likely in other upwelling zones, paleotemperature data derived

  18. Extended family medicine training

    Science.gov (United States)

    Slade, Steve; Ross, Shelley; Lawrence, Kathrine; Archibald, Douglas; Mackay, Maria Palacios; Oandasan, Ivy F.

    2016-01-01

    Abstract Objective To examine trends in family medicine training at a time when substantial pedagogic change is under way, focusing on factors that relate to extended family medicine training. Design Aggregate-level secondary data analysis based on the Canadian Post-MD Education Registry. Setting Canada. Participants All Canadian citizens and permanent residents who were registered in postgraduate family medicine training programs within Canadian faculties of medicine from 1995 to 2013. Main outcome measures Number and proportion of family medicine residents exiting 2-year and extended (third-year and above) family medicine training programs, as well as the types and numbers of extended training programs offered in 2015. Results The proportion of family medicine trainees pursuing extended training almost doubled during the study period, going from 10.9% in 1995 to 21.1% in 2013. Men and Canadian medical graduates were more likely to take extended family medicine training. Among the 5 most recent family medicine exit cohorts (from 2009 to 2013), 25.9% of men completed extended training programs compared with 18.3% of women, and 23.1% of Canadian medical graduates completed extended training compared with 13.6% of international medical graduates. Family medicine programs vary substantially with respect to the proportion of their trainees who undertake extended training, ranging from a low of 12.3% to a high of 35.1% among trainees exiting from 2011 to 2013. Conclusion New initiatives, such as the Triple C Competency-based Curriculum, CanMEDS–Family Medicine, and Certificates of Added Competence, have emerged as part of family medicine education and credentialing. In acknowledgment of the potential effect of these initiatives, it is important that future research examine how pedagogic change and, in particular, extended training shapes the care family physicians offer their patients. As part of that research it will be important to measure the breadth and uptake of

  19. The Extended Enterprise concept

    DEFF Research Database (Denmark)

    Larsen, Lars Bjørn; Vesterager, Johan; Gobbi, Chiara

    1999-01-01

    This paper provides an overview of the work that has been done regarding the Extended Enterprise concept in the Common Concept team of Globeman 21 including references to results deliverables concerning the development of the Extended Enterprise concept. The first section presents the basic concept...... picture from Globeman21, which illustrates the Globeman21 way of realising the Extended Enterprise concept. The second section presents the Globeman21 EE concept in a life cycle perspective, which to a large extent is based on the thoughts and ideas behind GERAM (ISO/DIS 15704)....

  20. Potential Predictability of the Sea-Surface Temperature Forced Equatorial East Africa Short Rains Interannual Variability in the 20th Century

    Science.gov (United States)

    Bahaga, T. K.; Gizaw, G.; Kucharski, F.; Diro, G. T.

    2014-12-01

    In this article, the predictability of the 20th century sea-surface temperature (SST) forced East African short rains variability is analyzed using observational data and ensembles of long atmospheric general circulation model (AGCM) simulations. To our knowledge, such an analysis for the whole 20th century using a series of AGCM ensemble simulations is carried out here for the first time. The physical mechanisms that govern the influence of SST on East African short rains in the model are also investigated. It is found that there is substantial skill in reproducing the East African short rains variability, given that the SSTs are known. Consistent with previous recent studies, it is found that the Indian Ocean and in particular the western pole of the Indian Ocean dipole (IOD) play a dominant role for the prediction skill, whereas SSTs outside the Indian Ocean play a minor role. The physical mechanism for the influence of the western Indian Ocean on East African rainfall in the model is consistent with previous findings and consists of a gill-type response to a warm (cold) anomaly that induces a westerly(easterly) low-level flow anomaly over equatorial Africa and leads to moisture flux convergence (divergence) over East Africa. On the other hand, a positive El Nino-Southern Oscillation (ENSO) anomaly leads to a spatially non-coherent reducing effect over parts of East Africa, but the relationship is not strong enough to provide any predictive skill in our model. The East African short rains prediction skill is also analyzed within a model-derived potential predictability framework and it is shown that the actual prediction skill is broadly consistent with the model potential prediction skill. Low-frequency variations of the prediction skill are mostly related to SSTs outside the Indian Ocean region and are likely due to an increased interference of ENSO with the Indian Ocean influence on East African short rains after the mid-1970s climate shift.

  1. Measurements of soil, surface water, and groundwater CO2 concentration variability within Earth's critical zone: low-cost, long-term, high-temporal resolution monitoring

    Science.gov (United States)

    Blackstock, J. M.; Covington, M. D.; Williams, S. G. W.; Myre, J. M.; Rodriguez, J.

    2017-12-01

    Variability in CO2 fluxes within Earth's Critical zone occurs over a wide range of timescales. Resolving this and its drivers requires high-temporal resolution monitoring of CO2 both in the soil and aquatic environments. High-cost (> 1,000 USD) gas analyzers and data loggers present cost-barriers for investigations with limited budgets, particularly if high spatial resolution is desired. To overcome high-costs, we developed an Arduino based CO2 measuring platform (i.e. gas analyzer and data logger). The platform was deployed at multiple sites within the Critical Zone overlying the Springfield Plateau aquifer in Northwest Arkansas, USA. The CO2 gas analyzer used in this study was a relatively low-cost SenseAir K30. The analyzer's optical housing was covered by a PTFE semi-permeable membrane allowing for gas exchange between the analyzer and environment. Total approximate cost of the monitoring platform was 200 USD (2% detection limit) to 300 USD (10% detection limit) depending on the K30 model used. For testing purposes, we deployed the Arduino based platform alongside a commercial monitoring platform. CO2 concentration time series were nearly identical. Notably, CO2 cycles at the surface water site, which operated from January to April 2017, displayed a systematic increase in daily CO2 amplitude. Preliminary interpretation suggests key observation of seasonally increasing stream metabolic function. Other interpretations of observed cyclical and event-based behavior are out of the scope of the study; however, the presented method describes an accurate near-hourly characterization of CO2 variability. The new platform has been shown to be operational for several months, and we infer reliable operation for much longer deployments (> 1 year) given adequate environmental protection and power supply. Considering cost-savings, this platform is an attractive option for continuous, accurate, low-power, and low-cost CO2 monitoring for remote locations, globally.

  2. An extended technicolor model

    International Nuclear Information System (INIS)

    Appelquist, T.; Terning, J.

    1994-01-01

    An extended technicolor model is constructed. Quark and lepton masses, spontaneous CP violation, and precision electroweak measurements are discussed. Dynamical symmetry breaking is analyzed using the concept of the big MAC (most attractive channel)

  3. Extending mine life

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    Mine layouts, new machines and techniques, research into problem areas of ground control and so on, are highlighted in this report on extending mine life. The main resources taken into account are coal mining, uranium mining, molybdenum and gold mining

  4. The dialogically extended mind

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Gangopadhyay, Nivedita; Tylén, Kristian

    2014-01-01

    A growing conceptual and empirical literature is advancing the idea that language extends our cognitive skills. One of the most influential positions holds that language – qua material symbols – facilitates individual thought processes by virtue of its material properties. Extending upon this model...... relate our approach to other ideas about collective minds and review a number of empirical studies to identify the mechanisms enabling the constitution of interpersonal cognitive systems....

  5. Extending Mondrian Memory Protection

    Science.gov (United States)

    2010-11-01

    a kernel semaphore is locked or unlocked. In addition, we extended the system call interface to receive notifications about user-land locking...operations (such as calls to the mutex and semaphore code provided by the C library). By patching the dynamically loadable GLibC5, we are able to test... semaphores , and spinlocks. RTO-MP-IST-091 10- 9 Extending Mondrian Memory Protection to loading extension plugins. This prevents any untrusted code

  6. Extended Life Coolant Testing

    Science.gov (United States)

    2016-06-06

    number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 06-06-2016 2. REPORT TYPE Interim Report 3. DATES COVERED ... Corrosion Testing of Traditional and Extended Life Coolants 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Hansen, Gregory A. T...providing vehicle specific coolants. Several laboratory corrosion tests were performed according to ASTM D1384 and D2570, but with a 2.5x extended time

  7. Interannual rainfall variability in the Amazon basin and sea-surface temperatures in the equatorial Pacific and the tropical Atlantic Oceans

    Science.gov (United States)

    Ronchail, Josyane; Cochonneau, Gérard; Molinier, Michel; Guyot, Jean-Loup; Chaves, Adriana Goretti De Miranda; Guimarães, Valdemar; de Oliveira, Eurides

    2002-11-01

    Rainfall variability in the Amazon basin is studied in relation to sea-surface temperatures (SSTs) in the equatorial Pacific and the northern and southern tropical Atlantic during the 1977-99 period, using the HiBAm original rainfall data set and complementary cluster and composite analyses.The northeastern part of the basin, north of 5 °S and east of 60 °W, is significantly related with tropical SSTs: a rainier wet season is observed when the equatorial Pacific and the northern (southern) tropical Atlantic are anomalously cold (warm). A shorter and drier wet season is observed during El Niño events and negative rainfall anomalies are also significantly associated with a warm northern Atlantic in the austral autumn and a cold southern Atlantic in the spring. The northeastern Amazon rainfall anomalies are closely related with El Niño-southern oscillation during the whole year, whereas the relationships with the tropical Atlantic SST anomalies are mainly observed during the autumn. A time-space continuity is observed between El Niño-related rainfall anomalies in the northeastern Amazon, those in the northern Amazon and south-eastern Amazon, and those in northern South America and in the Nordeste of Brazil.A reinforcement of certain rainfall anomalies is observed when specific oceanic events combine. For instance, when El Niño and cold SSTs in the southern Atlantic are associated, very strong negative anomalies are observed in the whole northern Amazon basin. Nonetheless, the comparison of the cluster and the composite analyses results shows that the rainfall anomalies in the northeastern Amazon are not always associated with tropical SST anomalies.In the southern and western Amazon, significant tropical SST-related rainfall anomalies are very few and spatially variable. The precipitation origins differ from those of the northeastern Amazon: land temperature variability, extratropical perturbations and moisture advection are important rainfall factors, as well

  8. Behaviour of the extended Toda lattice

    Science.gov (United States)

    Wattis, Jonathan A. D.; Gordoa, Pilar R.; Pickering, Andrew

    2015-11-01

    We consider the first member of an extended Toda lattice hierarchy. This system of equations is differential with respect to one independent variable and differential-delay with respect to a second independent variable. We use asymptotic analysis to consider the long wavelength limits of the system. By considering various magnitudes for the parameters involved, we derive reduced equations related to the Korteweg-de Vries and potential Boussinesq equations.

  9. Extending quantum mechanics entails extending special relativity

    International Nuclear Information System (INIS)

    Aravinda, S; Srikanth, R

    2016-01-01

    The complementarity between signaling and randomness in any communicated resource that can simulate singlet statistics is generalized by relaxing the assumption of free will in the choice of measurement settings. We show how to construct an ontological extension for quantum mechanics (QMs) through the oblivious embedding of a sound simulation protocol in a Newtonian spacetime. Minkowski or other intermediate spacetimes are ruled out as the locus of the embedding by virtue of hidden influence inequalities. The complementarity transferred from a simulation to the extension unifies a number of results about quantum non-locality, and implies that special relativity has a different significance for the ontological model and for the operational theory it reproduces. Only the latter, being experimentally accessible, is required to be Lorentz covariant. There may be certain Lorentz non-covariant elements at the ontological level, but they will be inaccessible at the operational level in a valid extension. Certain arguments against the extendability of QM, due to Conway and Kochen (2009) and Colbeck and Renner (2012), are attributed to their assumption that the spacetime at the ontological level has Minkowski causal structure. (paper)

  10. Minimal surfaces

    CERN Document Server

    Dierkes, Ulrich; Sauvigny, Friedrich; Jakob, Ruben; Kuster, Albrecht

    2010-01-01

    Minimal Surfaces is the first volume of a three volume treatise on minimal surfaces (Grundlehren Nr. 339-341). Each volume can be read and studied independently of the others. The central theme is boundary value problems for minimal surfaces. The treatise is a substantially revised and extended version of the monograph Minimal Surfaces I, II (Grundlehren Nr. 295 & 296). The first volume begins with an exposition of basic ideas of the theory of surfaces in three-dimensional Euclidean space, followed by an introduction of minimal surfaces as stationary points of area, or equivalently

  11. Metacognitive and Motivational Predictors of Surface Approach to Studying and Academic Examination Performance

    Science.gov (United States)

    Spada, Marcantonio M.; Moneta, Giovanni B.

    2014-01-01

    The objective of this study was to verify the structure of a model of how surface approach to studying is influenced by the trait variables of motivation and metacognition and the state variables of avoidance coping and evaluation anxiety. We extended the model to include: (1) the investigation of the relative contribution of the five…

  12. Onsager's reciprocity theorem in extended irreversible thermodynamics

    International Nuclear Information System (INIS)

    Garcia-Colin, L.S.; Velasco, R.M.

    1992-01-01

    In this paper we shall discuss the Onsager relations for the transport coefficients in a dilute monatomic gas described by the extended irreversible thermodynamics. Our discussion is based on a 26 variables description of the system and its corresponding comparison with the kinetic reciprocity between coefficients is shown (Author)

  13. Variability of onset and retreat of the rainy season in mainland China and associations with atmospheric circulation and sea surface temperature

    Science.gov (United States)

    Cao, Qing; Hao, Zhenchun; Shao, Quanxi; Hao, Jie; Nyima, Tsring

    2018-02-01

    Precipitation plays an important role in both environment and human society and is a significant factor in many scientific researches such as water resources, agriculture and climate impact studies. The onset and retreat of rainy season are useful features to understand the variability of precipitation under the influence of climate change. In this study, the characteristics of onset and retreat in mainland China are investigated. The multi-scale moving t-test was applied to determine rainy season and K-means cluster analysis was used to divide China into sub-regions to better investigate rainy season features. The possible linkage of changing characteristics of onset and retreat to climate factors were also explored. Results show that: (1) the onset started from middle March in the southeast of China to early June in the northwest and rainy season ended earliest in the northwest and southeast while the central China had the latest retreat; (2) Delayed onset and advanced retreat over time were observed in many parts of China, together with overall stable or increased rainy-season precipitation, would likely lead to higher probability of flooding; (3) The onset (retreat) was associated with the increased (decreased) number of cyclones in eastern China and anticyclone near the South China Sea. Delayed onset, and advanced retreat were likely related to cold and warm sea surface temperature (SST) in the conventional El Niño-Southern Oscillation (ENSO) regions, respectively. These results suggest that predictability of rainy season can be improved through the atmospheric circulation and SST, and help water resources management and agricultural planning.

  14. An Extended Duopoly Game.

    Science.gov (United States)

    Eckalbar, John C.

    2002-01-01

    Illustrates how principles and intermediate microeconomic students can gain an understanding for strategic price setting by playing a relatively large oligopoly game. Explains that the game extends to a continuous price space and outlines appropriate applications. Offers the Mathematica code to instructors so that the assumptions of the game can…

  15. Transversally extended string

    International Nuclear Information System (INIS)

    Akama, Keiichi

    1988-01-01

    Starting with the space-time action of the transversally extended string, we derive its world-sheet action, which is that of a gravitational and gauge theory with matter fields on the world-sheet, with additional effects of the second fundamental quantity. (author)

  16. Extended artistic appreciation.

    Science.gov (United States)

    Wilson, Robert A

    2013-04-01

    I propose that in at least some cases, objects of artistic appreciation are best thought of not simply as causes of artistic appreciation, but as parts of the cognitive machinery that drives aesthetic appreciation. In effect, this is to say that aesthetic appreciation operates via extended cognitive systems.

  17. Towards Extended Vantage Theory

    Science.gov (United States)

    Glaz, Adam

    2010-01-01

    The applicability of Vantage Theory (VT), a model of (colour) categorization, to linguistic data largely depends on the modifications and adaptations of the model for the purpose. An attempt to do so proposed here, called Extended Vantage Theory (EVT), slightly reformulates the VT conception of vantage by capitalizing on some of the entailments of…

  18. Long-term trends of surface ozone and its influencing factors at the Mt Waliguan GAW station, China – Part 2: The roles of anthropogenic emissions and climate variability

    Directory of Open Access Journals (Sweden)

    W. Xu

    2018-01-01

    Full Text Available Inter-annual variability and long-term trends in tropospheric ozone are both environmental and climate concerns. Ozone measured at Mt Waliguan Observatory (WLG, 3816 m a.s.l. on the Tibetan Plateau over the period of 1994–2013 has increased significantly by 0.2–0.3 ppbv yr−1 during spring and autumn but shows a much smaller trend in winter and no significant trend in summer. Here we explore the factors driving the observed ozone changes at WLG using backward trajectory analysis, chemistry–climate model hindcast simulations (GFDL AM3, a trajectory-mapped ozonesonde data set, and several climate indices. A stratospheric ozone tracer implemented in GFDL AM3 indicates that stratosphere-to-troposphere transport (STT can explain ∼ 60 % of the simulated springtime ozone increase at WLG, consistent with an increase in the NW air-mass frequency inferred from the trajectory analysis. Enhanced STT associated with the strengthening of the mid-latitude jet stream contributes to the observed high ozone anomalies at WLG during the springs of 1999 and 2012. During autumn, observations at WLG are more heavily influenced by polluted air masses originating from South East Asia than in the other seasons. Rising Asian anthropogenic emissions of ozone precursors are the key driver of increasing autumnal ozone observed at WLG, as supported by the GFDL AM3 model with time-varying emissions, which captures the observed ozone increase (0.26 ± 0.11 ppbv yr−1. AM3 simulates a greater ozone increase of 0.38 ± 0.11 ppbv yr−1 at WLG in autumn under conditions with strong transport from South East Asia and shows no significant ozone trend in autumn when anthropogenic emissions are held constant in time. During summer, WLG is mostly influenced by easterly air masses, but these trajectories do not extend to the polluted regions of eastern China and have decreased significantly over the last 2 decades, which likely explains why

  19. Harmonic superspaces of extended supersymmetry

    International Nuclear Information System (INIS)

    Ivanov, E.; Kalitzin, S.; Nguyen Ai Viet; Ogievetsky, V.

    1984-01-01

    The main technical apparatus of the harmonic superspace approach to extended SUSY, the calculus of harmonic variables on homogeneous spaces of the SUSY automorphism groups, is presented in detail for N=2, 3, 4. The basic harmonics for the coset manifolds G/H with G=SU(2), H=U(1); G=SU(3), H=SU(2)xU(1) and H=U(1)xU(1); G=SU(4), H=SU(3)xU(1), H=SU(2)xSU(2)xU(1), H=SU(2)xU(1)xU(1) and H=U(1)xU(1)xU(1); G=USp(2), H=SU(2)xSU(2), H=SU(2)xU(1) and H=U(1)xU(1) are tabulated a number of useful relations among them

  20. Hamiltonian dynamics of extended objects

    Science.gov (United States)

    Capovilla, R.; Guven, J.; Rojas, E.

    2004-12-01

    We consider relativistic extended objects described by a reparametrization-invariant local action that depends on the extrinsic curvature of the worldvolume swept out by the object as it evolves. We provide a Hamiltonian formulation of the dynamics of such higher derivative models which is motivated by the ADM formulation of general relativity. The canonical momenta are identified by looking at boundary behaviour under small deformations of the action; the relationship between the momentum conjugate to the embedding functions and the conserved momentum density is established. The canonical Hamiltonian is constructed explicitly; the constraints on the phase space, both primary and secondary, are identified and the role they play in the theory is described. The multipliers implementing the primary constraints are identified in terms of the ADM lapse and shift variables and Hamilton's equations are shown to be consistent with the Euler Lagrange equations.

  1. Hamiltonian dynamics of extended objects

    International Nuclear Information System (INIS)

    Capovilla, R; Guven, J; Rojas, E

    2004-01-01

    We consider relativistic extended objects described by a reparametrization-invariant local action that depends on the extrinsic curvature of the worldvolume swept out by the object as it evolves. We provide a Hamiltonian formulation of the dynamics of such higher derivative models which is motivated by the ADM formulation of general relativity. The canonical momenta are identified by looking at boundary behaviour under small deformations of the action; the relationship between the momentum conjugate to the embedding functions and the conserved momentum density is established. The canonical Hamiltonian is constructed explicitly; the constraints on the phase space, both primary and secondary, are identified and the role they play in the theory is described. The multipliers implementing the primary constraints are identified in terms of the ADM lapse and shift variables and Hamilton's equations are shown to be consistent with the Euler-Lagrange equations

  2. Hamiltonian dynamics of extended objects

    Energy Technology Data Exchange (ETDEWEB)

    Capovilla, R [Departamento de FIsica, Centro de Investigacion y de Estudios Avanzados del IPN, Apdo Postal 14-740, 07000 Mexico, DF (Mexico); Guven, J [School of Theoretical Physics, Dublin Institute for Advanced Studies, 10 Burlington Road, Dublin 4 (Ireland); Rojas, E [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apdo Postal 70-543, 04510 Mexico, DF (Mexico)

    2004-12-07

    We consider relativistic extended objects described by a reparametrization-invariant local action that depends on the extrinsic curvature of the worldvolume swept out by the object as it evolves. We provide a Hamiltonian formulation of the dynamics of such higher derivative models which is motivated by the ADM formulation of general relativity. The canonical momenta are identified by looking at boundary behaviour under small deformations of the action; the relationship between the momentum conjugate to the embedding functions and the conserved momentum density is established. The canonical Hamiltonian is constructed explicitly; the constraints on the phase space, both primary and secondary, are identified and the role they play in the theory is described. The multipliers implementing the primary constraints are identified in terms of the ADM lapse and shift variables and Hamilton's equations are shown to be consistent with the Euler-Lagrange equations.

  3. Characterization of the March 2017 tank 10 surface sample (combination of HTF-10-17-30 AND HTF-10-17-31) and variable depth sample (combination of HTF-10-17-32 and HTF-10-17-33)

    Energy Technology Data Exchange (ETDEWEB)

    Reboul, S. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-19

    Two surface samples (HTF-10-17-30 and HTF-10-17-31) and two variable depth samples (HTF-10-17-32 and HTF-10-17-33) were collected from SRS Tank 10 during March 2017 and submitted to SRNL for characterization. At SRNL, the two surface samples were combined in one container, the two variable depth samples (VDSs) were combined in another container, and then the two composite samples were each characterized by a series of physical, ionic, radiological, and elemental analysis methods. The surface sample composite was characterized primarily for Tank Farm corrosion control purposes, while the VDS composite was characterized primarily for Tank Closure Cesium Removal (TCCR) purposes.

  4. Extended quantum mechanics

    International Nuclear Information System (INIS)

    Pavel Bona

    2000-01-01

    The work can be considered as an essay on mathematical and conceptual structure of nonrelativistic quantum mechanics which is related here to some other (more general, but also to more special and 'approximative') theories. Quantum mechanics is here primarily reformulated in an equivalent form of a Poisson system on the phase space consisting of density matrices, where the 'observables', as well as 'symmetry generators' are represented by a specific type of real valued (densely defined) functions, namely the usual quantum expectations of corresponding selfjoint operators. It is shown in this paper that inclusion of additional ('nonlinear') symmetry generators (i. e. 'Hamiltonians') into this reformulation of (linear) quantum mechanics leads to a considerable extension of the theory: two kinds of quantum 'mixed states' should be distinguished, and operator - valued functions of density matrices should be used in the role of 'nonlinear observables'. A general framework for physical theories is obtained in this way: By different choices of the sets of 'nonlinear observables' we obtain, as special cases, e.g. classical mechanics on homogeneous spaces of kinematical symmetry groups, standard (linear) quantum mechanics, or nonlinear extensions of quantum mechanics; also various 'quasiclassical approximations' to quantum mechanics are all sub theories of the presented extension of quantum mechanics - a version of the extended quantum mechanics. A general interpretation scheme of extended quantum mechanics extending the usual statistical interpretation of quantum mechanics is also proposed. Eventually, extended quantum mechanics is shown to be (included into) a C * -algebraic (hence linear) quantum theory. Mathematical formulation of these theories is presented. The presentation includes an analysis of problems connected with differentiation on infinite-dimensional manifolds, as well as a solution of some problems connected with the work with only densely defined unbounded

  5. Propelling Extended Objects

    Science.gov (United States)

    Humbert, Richard

    2010-01-01

    A force acting on just part of an extended object (either a solid or a volume of a liquid) can cause all of it to move. That motion is due to the transmission of the force through the object by its material. This paper discusses how the force is distributed to all of the object by a gradient of stress or pressure in it, which creates the local…

  6. Extending Critical Performativity

    DEFF Research Database (Denmark)

    Spicer, André; Alvesson, Mats; Kärreman, Dan

    2016-01-01

    In this article we extend the debate about critical performativity. We begin by outlining the basic tenets of critical performativity and how this has been applied in the study of management and organization. We then address recent critiques of critical performance. We note these arguments suffer...... of public importance; engaging with non-academic groups using dialectical reasoning; scaling up insights through movement building; and propagating deliberation...

  7. Extended Theories of Gravity

    International Nuclear Information System (INIS)

    Capozziello, Salvatore; De Laurentis, Mariafelicia

    2011-01-01

    Extended Theories of Gravity can be considered as a new paradigm to cure shortcomings of General Relativity at infrared and ultraviolet scales. They are an approach that, by preserving the undoubtedly positive results of Einstein’s theory, is aimed to address conceptual and experimental problems recently emerged in astrophysics, cosmology and High Energy Physics. In particular, the goal is to encompass, in a self-consistent scheme, problems like inflation, dark energy, dark matter, large scale structure and, first of all, to give at least an effective description of Quantum Gravity. We review the basic principles that any gravitational theory has to follow. The geometrical interpretation is discussed in a broad perspective in order to highlight the basic assumptions of General Relativity and its possible extensions in the general framework of gauge theories. Principles of such modifications are presented, focusing on specific classes of theories like f(R)-gravity and scalar–tensor gravity in the metric and Palatini approaches. The special role of torsion is also discussed. The conceptual features of these theories are fully explored and attention is paid to the issues of dynamical and conformal equivalence between them considering also the initial value problem. A number of viability criteria are presented considering the post-Newtonian and the post-Minkowskian limits. In particular, we discuss the problems of neutrino oscillations and gravitational waves in extended gravity. Finally, future perspectives of extended gravity are considered with possibility to go beyond a trial and error approach.

  8. Task-specific noise exposure during manual concrete surface grinding in enclosed areas-influence of operation variables and dust control methods.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Ames, April L; Milz, Sheryl A; Akbar-Khanzadeh, Mahboubeh

    2013-01-01

    Noise exposure is a distinct hazard during hand-held concrete grinding activities, and its assessment is challenging because of the many variables involved. Noise dosimeters were used to examine the extent of personal noise exposure while concrete grinding was performed with a variety of grinder sizes, types, accessories, and available dust control methods. Noise monitoring was conducted in an enclosed area covering 52 task-specific grinding sessions lasting from 6 to 72 minutes. Noise levels, either in minute average noise level (Lavg, dBA) or in minute peak (dBC), during concrete grinding were significantly (P grinding cup wheel (blade) sizes of 4-inch (100 mm), 5-inch (125 mm) and 6-inch (150 mm), and surface orientation (horizontal, inclined). Overall, minute Lavg during grinding was 97.0 ± 3.3 (mean ± SD), ranging from 87.9 to 113. The levels of minute Lavg during uncontrolled grinding (98.9 ± 5.2) or wet-grinding (98.5 ± 2.7) were significantly higher than those during local exhaust ventilation (LEV) grinding (96.2 ± 2.8). A 6-inch grinding cup wheel generated significantly higher noise levels (98.7 ± 2.8) than 5-inch (96.3 ± 3.2) or 4-inch (95.3 ± 3.5) cup wheels. The minute peak noise levels (dBC) during grinding was 113 ± 5.2 ranging from 104 to 153. The minute peak noise levels during uncontrolled grinding (119 ± 10.2) were significantly higher than those during wet-grinding (115 ± 4.5) and LEV-grinding (112 ± 3.4). A 6-inch grinding cup wheel generated significantly higher minute peak noise levels (115 ± 5.3) than 5-inch (112 ± 4.5) or 4-inch (111 ± 5.4) cup wheels. Assuming an 8-hour work shift, the results indicated that noise exposure levels during concrete grinding in enclosed areas exceeded the recommended permissible exposure limits and workers should be protected by engineering control methods, safe work practices, and/or personal protective devices.

  9. Surface plasmon resonance analysis shows an IgG-isotype-specific defect in ABO blood group antibody formation in patients with common variable immunodeficiency

    Directory of Open Access Journals (Sweden)

    Michael Bernhard Fischer

    2015-05-01

    Full Text Available Background: Common variable immunodeficiency (CVID is the most common clinically severe primary immunodeficiency and comprises a heterogeneous group of patients with recurrent severe bacterial infections due to the failure to produce IgG antibodies after exposure to infectious agents and immunization. Diagnostic recommendations for antibody failure include assessment of isoagglutinins. We have readdressed this four decades old but still accepted recommendation with up to date methodology.Methods: Anti-A/B IgM- and IgG-antibodies were measured by Diamed-ID Micro Typing, surface plasmon resonance (SPR using the Biacore® device and flow cytometry.Results: When Diamed-ID Micro Typing was used, CVID patients (n=34 showed IgG- and IgM-isoagglutinins that were comparable to healthy volunteers (n=28, while all XLA patients (n=8 had none. Anti-A/B IgM-antibodies were present in more than 2/3 of the CVID patients and showed binding kinetics comparable to anti-A/B IgM-antibodies from healthy individuals. A correlation could be found in CVID patients between levels of anti-A/B IgM-antibodies and levels of serum IgM and PnP-IgM-antibodies. In contrast in CVID patients as a group ABO antibodies were significantly decreased when assessed by SPR, which correlated with levels of switched memory, non-switched memory and naïve B cells, but all CVID patients had low/undetectable anti-A/B IgG-antibodies.Conclusion: These results indicate that conventional isoagglutinin assessment and assessment of anti-A/B IgM antibodies are not suited for the diagnosis of impaired antibody production in CVID. Examination of anti-A/B IgG antibodies by SPR provides a useful method for the diagnosis of IgG antibody failure in all CVID patients studied, thus indicating an important additional rationale to start immunoglobulin replacement therapy early in these patients, before post-infectious sequelae develop.

  10. Spatiotemporal Co-variability of Surface Climate for Renewable Energy across the Contiguous United States: Role of the North Atlantic Subtropical High

    Science.gov (United States)

    Doering, K.; Steinschneider, S.

    2017-12-01

    The variability of renewable energy supply and drivers of demand across space and time largely determines the energy balance within power systems with a high penetration of renewable technologies. This study examines the joint spatiotemporal variability of summertime climate linked to renewable energy production (precipitation, wind speeds, insolation) and energy demand (temperature) across the contiguous United States (CONUS) between 1948 and 2015. Canonical correlation analysis is used to identify the major modes of joint variability between summer wind speeds and precipitation and related patterns of insolation and temperature. Canonical variates are then related to circulation anomalies to identify common drivers of the joint modes of climate variability. Results show that the first two modes of joint variability between summer wind speeds and precipitation exhibit pan-US dipole patterns with centers of action located in the eastern and central CONUS. Temperature and insolation also exhibit related US-wide dipoles. The relationship between canonical variates and lower-tropospheric geopotential height indicates that these modes are related to variability in the North Atlantic subtropical high (NASH). This insight can inform optimal strategies for siting renewables in an interconnected electric grid, and has implications for the impacts of climate variability and change on renewable energy systems.

  11. Extended Testability Analysis Tool

    Science.gov (United States)

    Melcher, Kevin; Maul, William A.; Fulton, Christopher

    2012-01-01

    The Extended Testability Analysis (ETA) Tool is a software application that supports fault management (FM) by performing testability analyses on the fault propagation model of a given system. Fault management includes the prevention of faults through robust design margins and quality assurance methods, or the mitigation of system failures. Fault management requires an understanding of the system design and operation, potential failure mechanisms within the system, and the propagation of those potential failures through the system. The purpose of the ETA Tool software is to process the testability analysis results from a commercial software program called TEAMS Designer in order to provide a detailed set of diagnostic assessment reports. The ETA Tool is a command-line process with several user-selectable report output options. The ETA Tool also extends the COTS testability analysis and enables variation studies with sensor sensitivity impacts on system diagnostics and component isolation using a single testability output. The ETA Tool can also provide extended analyses from a single set of testability output files. The following analysis reports are available to the user: (1) the Detectability Report provides a breakdown of how each tested failure mode was detected, (2) the Test Utilization Report identifies all the failure modes that each test detects, (3) the Failure Mode Isolation Report demonstrates the system s ability to discriminate between failure modes, (4) the Component Isolation Report demonstrates the system s ability to discriminate between failure modes relative to the components containing the failure modes, (5) the Sensor Sensor Sensitivity Analysis Report shows the diagnostic impact due to loss of sensor information, and (6) the Effect Mapping Report identifies failure modes that result in specified system-level effects.

  12. Extended Wordsearches in Chemistry

    Science.gov (United States)

    Cotton, Simon

    1998-04-01

    Students can be encouraged to develop their factual knowledge by use of puzzles. One strategy described here is the extended wordsearch, where the wordsearch element generates a number of words or phrases from which the answers to a series of questions are selected. The wordsearch can be generated with the aid of computer programs, though in order to make them suitable for students with dyslexia or other learning difficulties, a simpler form is more appropriate. These problems can be employed in a variety of contexts, for example, as topic tests and classroom end-of-lesson fillers. An example is provided in the area of calcium chemistry. Sources of suitable software are listed.

  13. Classical extended superconformal symmetries

    International Nuclear Information System (INIS)

    Viswanathan, R.R.

    1990-10-01

    Super-covariant differential operators are defined in two dimensions which map supersymmetry doublets to other doublets. The possibility of constructing a closed algebra among the fields appearing in such operators is explored. Such an algebra exists for Grassmann-odd differential operators. A representation for these operators in terms of free-field doublets is constructed. An explicit closed algebra involving fields of spin 2 and 5/2, in addition to the stress tensor and the supersymmetry generator, is constructed from such a free-field representation as an example of a non-linear extended superconformal algebra. (author). 9 refs

  14. Our Brains Extended

    Science.gov (United States)

    Prensky, Marc

    2013-01-01

    Technology is an extension of the brain; it is a new way of thinking. It is the solution humans have created to deal with the difficult new context of variability, uncertainty, complexity, and ambiguity. Wise integration of evolving and powerful technology demands a rethinking of the curriculum. This article discusses technology as the new way of…

  15. Influence of long-range atmospheric transport pathways and climate teleconnection patterns on the variability of surface 210Pb and 7Be concentrations in southwestern Europe.

    Science.gov (United States)

    Grossi, C; Ballester, J; Serrano, I; Galmarini, S; Camacho, A; Curcoll, R; Morguí, J A; Rodò, X; Duch, M A

    2016-12-01

    The variability of the atmospheric concentration of the 7 Be and 210 Pb radionuclides is strongly linked to the origin of air masses, the strength of their sources and the processes of wet and dry deposition. It has been shown how these processes and their variability are strongly affected by climate change. Thus, a deeper knowledge of the relationship between the atmospheric radionuclides variability measured close to the ground and these atmospheric processes could help in the analysis of climate scenarios. In the present study, we analyze the atmospheric variability of a 14-year time series of 7 Be and 210 Pb in a Mediterranean coastal city using a synergy of different indicators and tools such as: the local meteorological conditions, global and regional climate indexes and a lagrangian atmospheric transport model. We particularly focus on the relationships between the main pathways of air masses and sun spots occurrence, the variability of the local relative humidity and temperature conditions, and the main modes of regional climate variability, such as the North Atlantic Oscillation (NAO) and the Western Mediterranean Oscillation (WeMO). The variability of the observed atmospheric concentrations of both 7 Be and 210 Pb radionuclides was found to be mainly positively associated to the local climate conditions of temperature and to the pathways of air masses arriving at the station. Measured radionuclide concentrations significantly increase when air masses travel at low tropospheric levels from central Europe and the western part of the Iberian Peninsula, while low concentrations are associated with westerly air masses. We found a significant negative correlation between the WeMO index and the atmospheric variability of both radionuclides and no significant association was observed for the NAO index. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. An extended multivariate framework for drought monitoring in Mexico

    Science.gov (United States)

    Real-Rangel, Roberto; Pedrozo-Acuña, Adrián; Breña-Naranjo, Agustín; Alcocer-Yamanaka, Víctor

    2017-04-01

    Around the world, monitoring natural hazards, such as droughts, represents a critical task in risk assessment and management plans. A reliable drought monitoring system allows to identify regions affected by these phenomena so that early response measures can be implemented. In Mexico, this activity is performed using Mexico's Drought Monitor, which is based on a similar methodology as the United States Drought Monitor and the North American Drought Monitor. The main feature of these monitoring systems is the combination of ground-based and remote sensing observations that is ultimately validated by local experts. However, in Mexico in situ records of variables such as precipitation and streamflow are often scarce, or even null, in many regions of the country. Another issue that adds uncertainty in drought monitoring is the arbitrary weight given to each analyzed variable. This study aims at providing an operational framework for drought monitoring in Mexico, based on univariate and multivariate nonparametric standardized indexes proposed in recent studies. Furthermore, the framework has been extended by taking into account the Enhanced Vegetation Index (EVI) for the drought severity assessment. The analyzed variables used for computing the drought indexes are mainly derived from remote sensing (MODIS) and land surface models datasets (NASA MERRA-2). A qualitative evaluation of the results shows that the indexes used are capable of adequately describes the intensity and spatial distribution of past drought documented events.

  17. Extending ALCQIO with reachability

    OpenAIRE

    Kotek, Tomer; Simkus, Mantas; Veith, Helmut; Zuleger, Florian

    2014-01-01

    We introduce a description logic ALCQIO_{b,Re} which adds reachability assertions to ALCQIO, a sub-logic of the two-variable fragment of first order logic with counting quantifiers. ALCQIO_{b,Re} is well-suited for applications in software verification and shape analysis. Shape analysis requires expressive logics which can express reachability and have good computational properties. We show that ALCQIO_{b,Re} can describe complex data structures with a high degree of sharing and allows compos...

  18. Water availability as a driver of spatial and temporal variability in vegetation in the La Mancha plain (Spain): Implications for the land-surface energy, water and carbon budget

    Science.gov (United States)

    Los, Sietse

    2017-04-01

    Vegetation is water limited in large areas of Spain and therefore a close link exists between vegetation greenness observed from satellite and moisture availability. Here we exploit this link to infer spatial and temporal variability in moisture from MODIS NDVI data and thermal data. Discrepancies in the precipitation - vegetation relationship indicate areas with an alternative supply of water (i.e. not rainfall), this can be natural where moisture is supplied by upwelling groundwater, or can be artificial where crops are irrigated. As a result spatial and temporal variability in vegetation in the La Mancha Plain appears closely linked to topography, geology, rainfall and land use. Crop land shows large variability in year-to-year vegetation greenness; for some areas this variability is linked to variability in rainfall but in other cases this variability is linked to irrigation. The differences in irrigation treatment within one plant functional type, in this case crops, will lead to errors in land surface models when ignored. The magnitude of these effects on the energy, carbon and water balance are assessed at the scale of 250 m to 200 km. Estimating the water balance correctly is of particular important since in some areas in Spain more water is used for irrigation than is supplemented by rainfall.

  19. Extending juvenility in grasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaeppler, Shawn; de Leon Gatti, Natalia; Foerster, Jillian

    2017-04-11

    The present invention relates to compositions and methods for modulating the juvenile to adult developmental growth transition in plants, such as grasses (e.g. maize). In particular, the invention provides methods for enhancing agronomic properties in plants by modulating expression of GRMZM2G362718, GRMZM2G096016, or homologs thereof. Modulation of expression of one or more additional genes which affect juvenile to adult developmental growth transition such as Glossy15 or Cg1, in conjunction with such modulation of expression is also contemplated. Nucleic acid constructs for down-regulation of GRMZM2G362718 and/or GRMZM2G096016 are also contemplated, as are transgenic plants and products produced there from, that demonstrate altered, such as extended juvenile growth, and display associated phenotypes such as enhanced yield, improved digestibility, and increased disease resistance. Plants described herein may be used, for example, as improved forage or feed crops or in biofuel production.

  20. Extended biorthogonal matrix polynomials

    Directory of Open Access Journals (Sweden)

    Ayman Shehata

    2017-01-01

    Full Text Available The pair of biorthogonal matrix polynomials for commutative matrices were first introduced by Varma and Tasdelen in [22]. The main aim of this paper is to extend the properties of the pair of biorthogonal matrix polynomials of Varma and Tasdelen and certain generating matrix functions, finite series, some matrix recurrence relations, several important properties of matrix differential recurrence relations, biorthogonality relations and matrix differential equation for the pair of biorthogonal matrix polynomials J(A,B n (x, k and K(A,B n (x, k are discussed. For the matrix polynomials J(A,B n (x, k, various families of bilinear and bilateral generating matrix functions are constructed in the sequel.

  1. Extended conformal algebras

    International Nuclear Information System (INIS)

    Goddard, Peter

    1990-01-01

    The algebra of the group of conformal transformations in two dimensions consists of two commuting copies of the Virasoro algebra. In many mathematical and physical contexts, the representations of ν which are relevant satisfy two conditions: they are unitary and they have the ''positive energy'' property that L o is bounded below. In an irreducible unitary representation the central element c takes a fixed real value. In physical contexts, the value of c is a characteristic of a theory. If c < 1, it turns out that the conformal algebra is sufficient to ''solve'' the theory, in the sense of relating the calculation of the infinite set of physically interesting quantities to a finite subset which can be handled in principle. For c ≥ 1, this is no longer the case for the algebra alone and one needs some sort of extended conformal algebra, such as the superconformal algebra. It is these algebras that this paper aims at addressing. (author)

  2. Extended fuel cycle length

    International Nuclear Information System (INIS)

    Bruyere, M.; Vallee, A.; Collette, C.

    1986-09-01

    Extended fuel cycle length and burnup are currently offered by Framatome and Fragema in order to satisfy the needs of the utilities in terms of fuel cycle cost and of overall systems cost optimization. We intend to point out the consequences of an increased fuel cycle length and burnup on reactor safety, in order to determine whether the bounding safety analyses presented in the Safety Analysis Report are applicable and to evaluate the effect on plant licensing. This paper presents the results of this examination. The first part indicates the consequences of increased fuel cycle length and burnup on the nuclear data used in the bounding accident analyses. In the second part of this paper, the required safety reanalyses are presented and the impact on the safety margins of different fuel management strategies is examined. In addition, systems modifications which can be required are indicated