WorldWideScience

Sample records for stratocumulus topped marine

  1. Stratocumulus Cloud Top Radiative Cooling and Cloud Base Updraft Speeds

    Science.gov (United States)

    Kazil, J.; Feingold, G.; Balsells, J.; Klinger, C.

    2017-12-01

    Cloud top radiative cooling is a primary driver of turbulence in the stratocumulus-topped marine boundary. A functional relationship between cloud top cooling and cloud base updraft speeds may therefore exist. A correlation of cloud top radiative cooling and cloud base updraft speeds has been recently identified empirically, providing a basis for satellite retrieval of cloud base updraft speeds. Such retrievals may enable analysis of aerosol-cloud interactions using satellite observations: Updraft speeds at cloud base co-determine supersaturation and therefore the activation of cloud condensation nuclei, which in turn co-determine cloud properties and precipitation formation. We use large eddy simulation and an off-line radiative transfer model to explore the relationship between cloud-top radiative cooling and cloud base updraft speeds in a marine stratocumulus cloud over the course of the diurnal cycle. We find that during daytime, at low cloud water path (CWP correlated, in agreement with the reported empirical relationship. During the night, in the absence of short-wave heating, CWP builds up (CWP > 50 g m-2) and long-wave emissions from cloud top saturate, while cloud base heating increases. In combination, cloud top cooling and cloud base updrafts become weakly anti-correlated. A functional relationship between cloud top cooling and cloud base updraft speed can hence be expected for stratocumulus clouds with a sufficiently low CWP and sub-saturated long-wave emissions, in particular during daytime. At higher CWPs, in particular at night, the relationship breaks down due to saturation of long-wave emissions from cloud top.

  2. Cloud-Top Entrainment in Stratocumulus Clouds

    Science.gov (United States)

    Mellado, Juan Pedro

    2017-01-01

    Cloud entrainment, the mixing between cloudy and clear air at the boundary of clouds, constitutes one paradigm for the relevance of small scales in the Earth system: By regulating cloud lifetimes, meter- and submeter-scale processes at cloud boundaries can influence planetary-scale properties. Understanding cloud entrainment is difficult given the complexity and diversity of the associated phenomena, which include turbulence entrainment within a stratified medium, convective instabilities driven by radiative and evaporative cooling, shear instabilities, and cloud microphysics. Obtaining accurate data at the required small scales is also challenging, for both simulations and measurements. During the past few decades, however, high-resolution simulations and measurements have greatly advanced our understanding of the main mechanisms controlling cloud entrainment. This article reviews some of these advances, focusing on stratocumulus clouds, and indicates remaining challenges.

  3. Observational and Numerical Studies of the Boundary Layer, Cloud, and Aerosol Variability in the Southeast Pacific Coastal Marine Stratocumulus

    Science.gov (United States)

    2012-05-01

    Malinowski , J.-L., Brenguier and F. Burnet, 2005: Holes and entrainment in stratocumulus, J. Atmos. Sci., 62, 443-459. Ghate, V. P., B. A...Tennessee. Haman, K. E., S. P. Malinowski , M. J. Kurowski, H. Gerber, and J.-L. Brenguier, 2007: Small scale mixing processes at the top of a marine

  4. Evaluating aerosol indirect effect through marine stratocumulus clouds

    Energy Technology Data Exchange (ETDEWEB)

    Kogan, Z.N.; Kogan, Y.L.; Lilly, D.K. [Univ. of Oklahoma, Norman, OK (United States)

    1996-04-01

    During the last decade much attention has been focused on anthropogenic aerosols and their radiative influence on the global climate. Charlson et al. and Penner et al. have demonstrated that tropospheric aerosols and particularly anthropogenic sulfate aerosols may significantly contribute to the radiative forcing exerting a cooling influence on climate (-1 to -2 W/m{sup 2}) which is comparable in magnitude to greenhouse forcing, but opposite in sign. Aerosol particles affect the earth`s radiative budget either directly by scattering and absorption of solar radiation by themselves or indirectly by altering the cloud radiative properties through changes in cloud microstructure. Marine stratocumulus cloud layers and their possible cooling influence on the atmosphere as a result of pollution are of special interest because of their high reflectivity, durability, and large global cover. We present an estimate of thet aerosol indirect effect, or, forcing due to anthropogenic sulfate aerosols.

  5. Characteristics of vertical velocity in marine stratocumulus: comparison of large eddy simulations with observations

    International Nuclear Information System (INIS)

    Guo Huan; Liu Yangang; Daum, Peter H; Senum, Gunnar I; Tao, W-K

    2008-01-01

    We simulated a marine stratus deck sampled during the Marine Stratus/Stratocumulus Experiment (MASE) with a three-dimensional large eddy simulation (LES) model at different model resolutions. Various characteristics of the vertical velocity from the model simulations were evaluated against those derived from the corresponding aircraft in situ observations, focusing on standard deviation, skewness, kurtosis, probability density function (PDF), power spectrum, and structure function. Our results show that although the LES model captures reasonably well the lower-order moments (e.g., horizontal averages and standard deviations), it fails to simulate many aspects of the higher-order moments, such as kurtosis, especially near cloud base and cloud top. Further investigations of the PDFs, power spectra, and structure functions reveal that compared to the observations, the model generally underestimates relatively strong variations on small scales. The results also suggest that increasing the model resolutions improves the agreements between the model results and the observations in virtually all of the properties that we examined. Furthermore, the results indicate that a vertical grid size <10 m is necessary for accurately simulating even the standard-deviation profile, posing new challenges to computer resources.

  6. Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

    Directory of Open Access Journals (Sweden)

    Q. Yang

    2011-12-01

    Full Text Available This study assesses the ability of the recent chemistry version (v3.3 of the Weather Research and Forecasting (WRF-Chem model to simulate boundary layer structure, aerosols, stratocumulus clouds, and energy fluxes over the Southeast Pacific Ocean. Measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx and satellite retrievals (i.e., products from the MODerate resolution Imaging Spectroradiometer (MODIS, Clouds and Earth's Radiant Energy System (CERES, and GOES-10 are used for this assessment. The Morrison double-moment microphysics scheme is newly coupled with interactive aerosols in the model. The 31-day (15 October–16 November 2008 WRF-Chem simulation with aerosol-cloud interactions (AERO hereafter is also compared to a simulation (MET hereafter with fixed cloud droplet number concentrations in the microphysics scheme and simplified cloud and aerosol treatments in the radiation scheme. The well-simulated aerosol quantities (aerosol number, mass composition and optical properties, and the inclusion of full aerosol-cloud couplings lead to significant improvements in many features of the simulated stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness. In addition to accounting for the aerosol direct and semi-direct effects, these improvements feed back to the simulation of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengthens the temperature and humidity gradients within the capping inversion layer and lowers the marine boundary layer (MBL depth by 130 m from that of the MET simulation. These differences are associated with weaker entrainment and stronger mean subsidence at the top of the MBL in AERO. Mean top-of-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with

  7. Effect of biomass burning on marine stratocumulus clouds off the California coast

    Directory of Open Access Journals (Sweden)

    E.-Y. Hsie

    2009-11-01

    Full Text Available Aerosol-cloud interactions are considered to be one of the most important and least known forcings in the climate system. Biomass burning aerosols are of special interest due to their radiative impact (direct and indirect effect and their potential to increase in the future due to climate change. Combining data from Geostationary Operational Environmental Satellite (GOES and MODerate-resolution Imaging Spectroradiometer (MODIS with passive tracers from the FLEXPART Lagrangian Particle Dispersion Model, the impact of biomass burning aerosols on marine stratocumulus clouds has been examined in June and July of 2006–2008 off the California coast. Using a continental tracer, the indirect effect of biomass burning aerosols has been isolated by comparing the average cloud fraction and cloud albedo for different meteorological situations, and for clean versus polluted (in terms of biomass burning continental air masses at 14:00 local time. Within a 500 km-wide band along the coast of California, biomass burning aerosols, which tend to reside above the marine boundary layer, increased the cloud fraction by 0.143, and the cloud albedo by 0.038. Absorbing aerosols located above the marine boundary layer lead to an increase of the lower tropospheric stability and a reduction in the vertical entrainment of dry air from above, leading to increased cloud formation. The combined effect was an indirect radiative forcing of −7.5% ±1.7% (cooling effect of the outgoing radiative flux at the top of the atmosphere on average, with a bias due to meteorology of +0.9%. Further away from the coast, the biomass burning aerosols, which were located within the boundary layer, reduced the cloud fraction by 0.023 and the cloud albedo by 0.006, resulting in an indirect radiative forcing of +1.3% ±0.3% (warming effect with a bias of +0.5%. These results underscore the dual role that absorbing aerosols play in cloud radiative forcing.

  8. Modified ultrafast thermometer UFT-M and temperature measurements during Physics of Stratocumulus Top (POST

    Directory of Open Access Journals (Sweden)

    W. Kumala

    2013-08-01

    Full Text Available A modified UFT-M version of the ultrafast airborne thermometer UFT, aimed at in-cloud temperature measurements, was designed for the Physics of Stratocumulus Top (POST field campaign. Improvements in its construction resulted in the sensor's increased reliability, which provided valuable measurements in 15 of the 17 flights. Oversampling the data allowed for the effective correction of the artefacts resulting from the interference with electromagnetic transmissions from on-board avionic systems and the thermal noise resulting from the sensor construction. The UFT-M records, when averaged to the 1.4 and 55 m resolutions, compared to the similar records of a thermometer in a Rosemount housing, indicate that the housing distorts even low-resolution airborne temperature measurements. Data collected with the UFT-M during the course of POST characterise the thermal structure of stratocumulus and capping inversion with the maximum resolution of ~1 cm. In this paper, examples of UFT-M records are presented and discussed.

  9. Microphysical structure of simulated marine stratocumulus: Effects of physical and numerical approximations

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, B.; Cotton, W.R. [Colorado State Univ., Fort Collins, CO (United States); Feingold, G. [Cooperative Institute for Research in the Atmospheric (CIRA), Fort Collins, CO (United States)

    1996-04-01

    Over the past decade or so the evolution and equilibria of persistent decks of stratocumulus climatologically clinging to the edge of summertime subtropical highs have been an issue of increased scientific inquiry. The particular interest in the microphysical structure of these clouds stems from a variety of hypotheses which suggest that anthropogenic influences or biogenic feedbacks may alter the structure of these clouds in a climatically significant manner. Most of these hypotheses are quite tentative, based as they are on simple formulations of boundary layer structures and interactions between drops and aerosols. This work is concerned with an assessment of the microphysical structure of marine stratocumulus as simulated by an LES-EM model.

  10. Relating large-scale subsidence to convection development in Arctic mixed-phase marine stratocumulus

    Science.gov (United States)

    Young, Gillian; Connolly, Paul J.; Dearden, Christopher; Choularton, Thomas W.

    2018-02-01

    Large-scale subsidence, associated with high-pressure systems, is often imposed in large-eddy simulation (LES) models to maintain the height of boundary layer (BL) clouds. Previous studies have considered the influence of subsidence on warm liquid clouds in subtropical regions; however, the relationship between subsidence and mixed-phase cloud microphysics has not specifically been studied. For the first time, we investigate how widespread subsidence associated with synoptic-scale meteorological features can affect the microphysics of Arctic mixed-phase marine stratocumulus (Sc) clouds. Modelled with LES, four idealised scenarios - a stable Sc, varied droplet (Ndrop) or ice (Nice) number concentrations, and a warming surface (representing motion southwards) - were subjected to different levels of subsidence to investigate the cloud microphysical response. We find strong sensitivities to large-scale subsidence, indicating that high-pressure systems in the ocean-exposed Arctic regions have the potential to generate turbulence and changes in cloud microphysics in any resident BL mixed-phase clouds.Increased cloud convection is modelled with increased subsidence, driven by longwave radiative cooling at cloud top and rain evaporative cooling and latent heating from snow growth below cloud. Subsidence strengthens the BL temperature inversion, thus reducing entrainment and allowing the liquid- and ice-water paths (LWPs, IWPs) to increase. Through increased cloud-top radiative cooling and subsequent convective overturning, precipitation production is enhanced: rain particle number concentrations (Nrain), in-cloud rain mass production rates, and below-cloud evaporation rates increase with increased subsidence.Ice number concentrations (Nice) play an important role, as greater concentrations suppress the liquid phase; therefore, Nice acts to mediate the strength of turbulent overturning promoted by increased subsidence. With a warming surface, a lack of - or low - subsidence

  11. On the relevance of droplet sedimentation in stratocumulus-top mixing

    Science.gov (United States)

    Mellado, Juan Pedro; de Lozar, Alberto

    2017-11-01

    The interaction between droplet sedimentation, turbulent mixing, evaporative cooling, and radiative cooling at the top of stratocumulus clouds has been studied using direct numerical simulations. This interaction is important to determine the mixing rate of the cloud and dry air above it, which eventually determines the cloud lifetime. By investigating the entrainment-rate equation, which is an analytical relationship between the contributions to cloud-top entrainment from the phenomena indicated above, we have found that the reduction of entrainment velocity by droplet sedimentation can be 2 to 3 times larger than previously conjectured. The reason is twofold. First, the reduction of evaporative cooling as droplets fall out of the inversion is stronger than previously observed in large-eddy simulations, where excessive mixing by turbulence models and numerical artifacts may have partially masked this effect of sedimentation on entrainment. Second, there is a non-negligible direct contribution from mass loading, as falling droplets leave behind more buoyant air in the inversion. This contribution is proportional to the fifth moment of the droplet-size distribution, which provides further evidence for the need to better understand the evolution of the droplet-size distribution.

  12. Marine Stratocumulus Properties from the FPDR - PDI as a Function of Aerosol during ORACLES

    Science.gov (United States)

    Small Griswold, J. D.; Heikkila, A.

    2016-12-01

    Aerosol-cloud interactions in the southeastern Atlantic (SEA) region were investigated during year 1 of the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field project in Aug-Sept 2016. This region is of interest due to seasonally persistent marine stratocumulus cloud decks that are an important component of the climate system due to their radiative and hydrologic impacts. The SEA deck is unique due to the interactions between these clouds and transported biomass burning aerosol during the July-October fire season. These biomass burning aerosol play multiple roles in modifying the cloud deck through interactions with radiation as absorbing aerosol and through modifications to cloud microphysical properties as cloud condensation nuclei. This work uses in situcloud data obtained with a Flight Probe Dual Range - Phase Doppler Interferometer (FPDR - PDI), standard aerosol instrumentation on board the NASA P-3, and reanalysis data to investigate Aerosol-Cloud Interactions (ACI). The FPDR - PDI provides unique cloud microphysical observations of individual cloud drop arrivals allowing for the computation of a variety of microphysical cloud properties including individual drop size, cloud drop number concentration, cloud drop size distributions, liquid water content, and cloud thickness. The FPDR - PDI measurement technique also provides droplet spacing and drop velocity information which is used to investigate turbulence and entrainment mixing processes. We use aerosol information such as average background aerosol amount (low, mid, high) and location relative to cloud (above or mixing) to sort FPDR - PDI cloud properties. To control for meteorological co-variances we further sort the data within aerosol categories by lower tropospheric stability, vertical velocity, and surface wind direction. We then determine general marine stratocumulus cloud characteristics under each of the various aerosol categories to investigate ACI in the SEA.

  13. Ozone budgets from the Dynamics and Chemistry of Marine Stratocumulus experiment

    Science.gov (United States)

    Kawa, S. R.; Pearson, R., Jr.

    1989-01-01

    Measurements from the Dynamics and Chemistry of marine Stratocumulus experiment have been used to study components of the regional ozone budget. The surface destruction rate is determined by eddy correlation of ozone and vertical velocity measured by a low-flying aircraft. Significant variability is found in the measured surface resistance; it is partially correlated with friction velocity but appears to have other controlling influences as well. The mean resistance is 4190 s/m which is higher (slower destruction) than most previous estimates for seawater. Flux and mean measurements throughout the marine boundary layer are used to estimate the net rate of in situ photochemical production/destruction of ozone. Averaged over the flights, ozone concentration is found to be near steady state, and a net of photochemical destruction of 0.02-0.07 ng/cu m per sec is diagnosed. This is an important confirmation of photochemical model results for the remote marine boundary layer. Ozone vertical distributions above the boundary layer show a strongly layered structure with very sharp gradients. These distributions are possibly related to the stratospheric ozone source.

  14. Low cloud precipitation climatology in the southeastern Pacific marine stratocumulus region using CloudSat

    International Nuclear Information System (INIS)

    Rapp, Anita D; Lebsock, Matthew; L’Ecuyer, Tristan

    2013-01-01

    A climatology of low cloud surface precipitation occurrence and intensity from the new CloudSat 2C-RAIN-PROFILE algorithm is presented from June 2006 through December 2010 for the southeastern Pacific region of marine stratocumulus. Results show that over 70% of low cloud precipitation falls as drizzle. Application of an empirical evaporation model suggests that 50–80% of the precipitation evaporates before it reaches the surface. Segregation of the CloudSat ascending and descending overpasses shows that the majority of precipitation occurs at night. Examination of the seasonal cycle shows that the precipitation is most frequent during the austral winter and spring; however there is considerable regional variability. Conditional rain rates increase from east to west with a maximum occurring in the region influenced by the South Pacific Convergence Zone. Area average rain rates are highest in the region where precipitation rates are moderate, but most frequent. The area average surface rain rate for low cloud precipitation for this region is ∼0.22 mm d −1 , in good agreement with in situ estimates, and is greatly improved over earlier CloudSat precipitation products. These results provide a much-needed quantification of surface precipitation in a region that is currently underestimated in existing satellite-based precipitation climatologies. (letter)

  15. Climate change and marine top predators

    DEFF Research Database (Denmark)

    Climate change affects all components of marine ecosystems. For endothermic top predators, i.e. seabirds and marine mammals, these impacts are often complex and mediated through trophic relationships. In this Research Topic, leading researchers attempt to identify patterns of change among seabirds...... and marine mammals, and the mechanisms through which climate change drives these changes....

  16. Optical and Microphysical Retrievals of Marine Stratocumulus Clouds off the Coast of Namibia from Satellite and Aircraft

    Science.gov (United States)

    Platnick, Steven E.

    2010-01-01

    Though the emphasis of the Southern Africa Regional Science Initiative 2000 (SAFARI-2000) dry season campaign was largely on emission sources and transport, the assemblage of aircraft (including the high altitude NASA ER-2 remote sensing platform and the University of Washington CV-580, UK MRF C-130, and South African Weather Bureau JRA in situ aircrafts) provided a unique opportunity for cloud studies. Therefore, as part of the SAFARI initiative, investigations were undertaken to assess regional aerosol-cloud interactions and cloud remote sensing algorithms. In particular, the latter part of the experiment concentrated on marine boundary layer stratocumulus clouds off the southwest coast of Africa. Associated with cold water upwelling along the Benguela current, the Namibian stratocumulus regime has received limited attention but appears to be unique for several reasons. During the dry season, outflow of continental fires and industrial pollution over this area can be extreme. From below, upwelling provides a rich nutrient source for phytoplankton (a source of atmospheric sulfur through DMS production as well as from decay processes). The impact of these natural and anthropogenic sources on the microphysical and optical properties of the stratocumulus is unknown. Continental and Indian Ocean cloud systems of opportunity were also studied during the campaign. SAFARI 2000 aircraft flights off the coast of Namibia were coordinated with NASA Terra Satellite overpasses for synergy with the Moderate Resolution Imaging Spectroradiometer (MODIS) and other Terra instruments. MODIS was developed by NASA and launched onboard the Terra spacecraft on December 18, 1999 (and Aqua spacecraft on May 4, 2002). Among the remote sensing algorithms developed and applied to this sensor are cloud optical and microphysical properties that include cloud thermodynamic phase, optical thickness, and effective particle radius of both liquid water and ice clouds. The archived products from

  17. Scaling analysis of cloud and rain water in marine stratocumulus and implications for scale-aware microphysical parameterizations

    Science.gov (United States)

    Witte, M.; Morrison, H.; Jensen, J. B.; Bansemer, A.; Gettelman, A.

    2017-12-01

    The spatial covariance of cloud and rain water (or in simpler terms, small and large drops, respectively) is an important quantity for accurate prediction of the accretion rate in bulk microphysical parameterizations that account for subgrid variability using assumed probability density functions (pdfs). Past diagnoses of this covariance from remote sensing, in situ measurements and large eddy simulation output have implicitly assumed that the magnitude of the covariance is insensitive to grain size (i.e. horizontal resolution) and averaging length, but this is not the case because both cloud and rain water exhibit scale invariance across a wide range of scales - from tens of centimeters to tens of kilometers in the case of cloud water, a range that we will show is primarily limited by instrumentation and sampling issues. Since the individual variances systematically vary as a function of spatial scale, it should be expected that the covariance follows a similar relationship. In this study, we quantify the scaling properties of cloud and rain water content and their covariability from high frequency in situ aircraft measurements of marine stratocumulus taken over the southeastern Pacific Ocean aboard the NSF/NCAR C-130 during the VOCALS-REx field experiment of October-November 2008. First we confirm that cloud and rain water scale in distinct manners, indicating that there is a statistically and potentially physically significant difference in the spatial structure of the two fields. Next, we demonstrate that the covariance is a strong function of spatial scale, which implies important caveats regarding the ability of limited-area models with domains smaller than a few tens of kilometers across to accurately reproduce the spatial organization of precipitation. Finally, we present preliminary work on the development of a scale-aware parameterization of cloud-rain water subgrid covariability based in multifractal analysis intended for application in large-scale model

  18. Coupling spectral-bin cloud microphysics with the MOSAIC aerosol model in WRF-Chem: Methodology and results for marine stratocumulus clouds

    Science.gov (United States)

    Gao, Wenhua; Fan, Jiwen; Easter, R. C.; Yang, Qing; Zhao, Chun; Ghan, Steven J.

    2016-09-01

    Aerosol-cloud interaction processes can be represented more physically with bin cloud microphysics relative to bulk microphysical parameterizations. However, due to computational power limitations in the past, bin cloud microphysics was often run with very simple aerosol treatments. The purpose of this study is to represent better aerosol-cloud interaction processes in the Chemistry version of Weather Research and Forecast model (WRF-Chem) at convection-permitting scales by coupling spectral-bin cloud microphysics (SBM) with the MOSAIC sectional aerosol model. A flexible interface is built that exchanges cloud and aerosol information between them. The interface contains a new bin aerosol activation approach, which replaces the treatments in the original SBM. It also includes the modified aerosol resuspension and in-cloud wet removal processes with the droplet loss tendencies and precipitation fluxes from SBM. The newly coupled system is evaluated for two marine stratocumulus cases over the Southeast Pacific Ocean with either a simplified aerosol setup or full-chemistry. We compare the aerosol activation process in the newly coupled SBM-MOSAIC against the SBM simulation without chemistry using a simplified aerosol setup, and the results show consistent activation rates. A longer time simulation reinforces that aerosol resuspension through cloud drop evaporation plays an important role in replenishing aerosols and impacts cloud and precipitation in marine stratocumulus clouds. Evaluation of the coupled SBM-MOSAIC with full-chemistry using aircraft measurements suggests that the new model works realistically for the marine stratocumulus clouds, and improves the simulation of cloud microphysical properties compared to a simulation using MOSAIC coupled with the Morrison two-moment microphysics.

  19. Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific coastal marine stratocumulus during VOCALS-REx

    Science.gov (United States)

    Zheng, X.; Albrecht, B.; Jonsson, H. H.; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

    2011-05-01

    Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud-Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. The BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL on days without predominately synoptic and meso-scale influences. The BL had a depth of 1140 ± 120 m, was well-mixed and capped by a sharp inversion. The wind direction generally switched from southerly within the BL to northerly above the inversion. The cloud liquid water path (LWP) varied between 15 g m-2 and 160 g m-2. From 29 October to 4 November, when a synoptic system affected conditions at Point Alpha, the cloud LWP was higher than on the other days by around 40 g m-2. On 1 and 2 November, a moist layer above the inversion moved over Point Alpha. The total-water specific humidity above the inversion was larger than that within the BL during these days. Entrainment rates (average of 1.5 ± 0.6 mm s-1) calculated from the near cloud-top fluxes and turbulence (vertical velocity variance) in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The accumulation mode aerosol varied from 250 to 700 cm-3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm-3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm-3, which was consistent with the satellite-derived values. The relationship of cloud droplet number concentration and CCN at 0.2 % supersaturation from 18 flights is Nd =4.6 × CCN0.71. While the mean LWP

  20. Biomass smoke from southern Africa can significantly enhance the brightness of stratocumulus over the southeastern Atlantic Ocean

    Science.gov (United States)

    Lu, Zheng; Liu, Xiaohong; Zhang, Zhibo; Zhao, Chun; Meyer, Kerry; Rajapakshe, Chamara; Wu, Chenglai; Yang, Zhifeng; Penner, Joyce E.

    2018-03-01

    Marine stratocumulus clouds cover nearly one-quarter of the ocean surface and thus play an extremely important role in determining the global radiative balance. The semipermanent marine stratocumulus deck over the southeastern Atlantic Ocean is of particular interest, because of its interactions with seasonal biomass burning aerosols that are emitted in southern Africa. Understanding the impacts of biomass burning aerosols on stratocumulus clouds and the implications for regional and global radiative balance is still very limited. Previous studies have focused on assessing the magnitude of the warming caused by solar scattering and absorption by biomass burning aerosols over stratocumulus (the direct radiative effect) or cloud adjustments to the direct radiative effect (the semidirect effect). Here, using a nested modeling approach in conjunction with observations from multiple satellites, we demonstrate that cloud condensation nuclei activated from biomass burning aerosols entrained into the stratocumulus (the microphysical effect) can play a dominant role in determining the total radiative forcing at the top of the atmosphere, compared with their direct and semidirect radiative effects. Biomass burning aerosols over the region and period with heavy loadings can cause a substantial cooling (daily mean ‑8.05 W m‑2), primarily as a result of clouds brightening by reducing the cloud droplet size (the Twomey effect) and secondarily through modulating the diurnal cycle of cloud liquid water path and coverage (the cloud lifetime effect). Our results highlight the importance of realistically representing the interactions of stratocumulus with biomass burning aerosols in global climate models in this region.

  1. Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific coastal marine stratocumulus during VOCALS-REx

    OpenAIRE

    X. Zheng; B. Albrecht; H. H. Jonsson; D. Khelif; G. Feingold; P. Minnis; K. Ayers; P. Chuang; S. Donaher; D. Rossiter; V. Ghate; J. Ruiz-Plancarte; S. Sun-Mack

    2011-01-01

    Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud-Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. The BL at Point Alpha was typical of a non-drizzling stratocumulus-t...

  2. An LES model study of the influence of the free tropospheric thermodynamic conditions on the stratocumulus response to a climate perturbation

    NARCIS (Netherlands)

    Van der Dussen, J.J.; De Roode, S.R.; Dal Gesso, S.; Siebesma, A.P.

    2015-01-01

    Twenty-five large-eddy simulations are performed to study how free tropospheric thermodynamic conditions control equilibrium state solutions of stratocumulus-topped marine boundary layers. In particular, we systematically vary the lower tropospheric stability (LTS) and a similar measure for the bulk

  3. The GASS/EUCLIPSE model intercomparison of the stratocumulus transition as observed during ASTEX : LES results

    NARCIS (Netherlands)

    Van der Dussen, J.J.; De Roode, S.R.; Ackerman, A.S.; Blossey, P.N.; Bretherton, C.S.; Kurowski, M.J.; Lock, A.P.; Neggers, R.A.J.; Sandu, I.; Siebesma, A.P.

    2013-01-01

    Large-eddy simulations of a Lagrangian transition from a vertically well-mixed stratocumulus-topped boundary layer to a situation in which shallow cumuli penetrate an overlying layer of thin and broken stratocumulus are compared with aircraft observations collected during the Atlantic Stratocumulus

  4. Dynamics, thermodynamics, radiation, and cloudiness associated with cumulus-topped marine boundary layers

    Energy Technology Data Exchange (ETDEWEB)

    Ghate, Virendra P. [Argonne National Lab. (ANL), Argonne, IL (United States); Miller, Mark [Rutgers Univ., New Brunswick, NJ (United States)

    2016-11-01

    The overall goal of this project was to improve the understanding of marine boundary clouds by using data collected at the Atmospheric Radiation Measurement (ARM) sites, so that they can be better represented in global climate models (GCMs). Marine boundary clouds are observed regularly over the tropical and subtropical oceans. They are an important element of the Earth’s climate system because they have substantial impact on the radiation budget together with the boundary layer moisture, and energy transports. These clouds also have an impact on large-scale precipitation features like the Inter Tropical Convergence Zone (ITCZ). Because these clouds occur at temporal and spatial scales much smaller than those relevant to GCMs, their effects and the associated processes need to be parameterized in GCM simulations aimed at predicting future climate and energy needs. Specifically, this project’s objectives were to (1) characterize the surface turbulent fluxes, boundary layer thermodynamics, radiation field, and cloudiness associated with cumulus-topped marine boundary layers; (2) explore the similarities and differences in cloudiness and boundary layer conditions observed in the tropical and trade-wind regions; and (3) understand similarities and differences by using a simple bulk boundary layer model. In addition to working toward achieving the project’s three objectives, we also worked on understanding the role played by different forcing mechanisms in maintaining turbulence within cloud-topped boundary layers We focused our research on stratocumulus clouds during the first phase of the project, and cumulus clouds during the rest of the project. Below is a brief description of manuscripts published in peer-reviewed journals that describe results from our analyses.

  5. A multi-year data set on aerosol-cloud-precipitation-meteorology interactions for marine stratocumulus clouds.

    Science.gov (United States)

    Sorooshian, Armin; MacDonald, Alexander B; Dadashazar, Hossein; Bates, Kelvin H; Coggon, Matthew M; Craven, Jill S; Crosbie, Ewan; Hersey, Scott P; Hodas, Natasha; Lin, Jack J; Negrón Marty, Arnaldo; Maudlin, Lindsay C; Metcalf, Andrew R; Murphy, Shane M; Padró, Luz T; Prabhakar, Gouri; Rissman, Tracey A; Shingler, Taylor; Varutbangkul, Varuntida; Wang, Zhen; Woods, Roy K; Chuang, Patrick Y; Nenes, Athanasios; Jonsson, Haflidi H; Flagan, Richard C; Seinfeld, John H

    2018-02-27

    Airborne measurements of meteorological, aerosol, and stratocumulus cloud properties have been harmonized from six field campaigns during July-August months between 2005 and 2016 off the California coast. A consistent set of core instruments was deployed on the Center for Interdisciplinary Remotely-Piloted Aircraft Studies Twin Otter for 113 flight days, amounting to 514 flight hours. A unique aspect of the compiled data set is detailed measurements of aerosol microphysical properties (size distribution, composition, bioaerosol detection, hygroscopicity, optical), cloud water composition, and different sampling inlets to distinguish between clear air aerosol, interstitial in-cloud aerosol, and droplet residual particles in cloud. Measurements and data analysis follow documented methods for quality assurance. The data set is suitable for studies associated with aerosol-cloud-precipitation-meteorology-radiation interactions, especially owing to sharp aerosol perturbations from ship traffic and biomass burning. The data set can be used for model initialization and synergistic application with meteorological models and remote sensing data to improve understanding of the very interactions that comprise the largest uncertainty in the effect of anthropogenic emissions on radiative forcing.

  6. Simulation of Optical Properties and Direct and Indirect Radiative Effects of Smoke Aerosols Over Marine Stratocumulus Clouds During Summer 2008 in California With the Regional Climate Model RegCM

    Science.gov (United States)

    Mallet, M.; Solmon, F.; Roblou, L.; Peers, F.; Turquety, S.; Waquet, F.; Jethva, H.; Torres, O.

    2017-10-01

    The regional climate model RegCM has been modified to better account for the climatic effects of biomass-burning particles. Smoke aerosols are represented by new tracers with consistent radiative and hygroscopic properties to simulate the direct radiative forcing (DRF), and a new parameterization has been integrated for relating the droplet number concentration to the aerosol concentration for marine stratocumulus clouds (Sc). RegCM has been tested during the summer of 2008 over California, when extreme concentration of smoke, together with the presence of Sc, is observed. This work indicates that significant aerosol optical depth (AOD) ( 1-2 at 550 nm) is related to the intense 2008 fires. Compared to Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer, the regional pattern of RegCM AOD is well represented although the magnitude is lower than satellite observations. Comparisons with Polarization and Directionality of Earth Reflectances (POLDER) above-clouds aerosol optical depth (ACAOD) show the ability of RegCM to simulate realistic ACAOD during the transport of smoke above the Pacific Ocean. The simulated single scattering albedo is 0.90 (at 550 nm) near biomass-burning sources, consistent with OMI and POLDER, and smoke leads to shortwave heating rates 1.5-2°K d-1. RegCM is not able to correctly resolve the daily patterns in cloud properties notably due to its coarse horizontal resolutions. However, the changes in the sign of the DRF at top of atmosphere (TOA) (negative to positive) from clear-sky to all-sky conditions is well simulated. Finally, the "aerosol-cloud" parameterization allows simulating an increase of the cloud optical depth for significant concentrations, leading to large perturbations of radiative fluxes at TOA.

  7. Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific near-coastal marine stratocumulus during VOCALS-REx

    Science.gov (United States)

    Zheng, X.; Albrecht, B.; Jonsson, H. H.; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

    2011-09-01

    Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud- Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP) varied between 15 g m-2 and 160 g m-2. The BL had a depth of 1140 ± 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and meso-scale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October-4 November), a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm-3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm-3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm-3. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft in situ observations near cloud top. The aerosol and cloud LWP

  8. Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific near-coastal marine stratocumulus during VOCALS-REx

    Directory of Open Access Journals (Sweden)

    X. Zheng

    2011-09-01

    Full Text Available Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud- Atmosphere-Land Study-Regional Experiment (VOCALS-REx, combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP varied between 15 g m−2 and 160 g m−2. The BL had a depth of 1140 ± 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and meso-scale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October–4 November, a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm−3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm−3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm−3. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the

  9. A treatment for the stratocumulus-to-cumulus transition in GCMs

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Heng; Mechoso, C.R. [University of California, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA (United States); Wu, Chien-Ming [National Taiwan University, Department of Atmospheric Sciences, Taipei (China); Ma, Hsi-Yen [Lawrence Livermore National Laboratory, Program for Climate Model Diagnosis and Intercomparison, Livermore, CA (United States)

    2012-12-15

    Numerical models of climate have great difficulties with the simulation of marine low clouds in the subtropical Pacific and Atlantic Oceans. It has been especially difficult to reproduce the observed geographical distributions of the different cloud regimes in those regions. The present study discusses mechanisms proposed in previous works for changing one regime into another. One criterion is based on the theory of stratocumulus destruction through cloud top entrainment instability due to buoyancy reversal - situations in which the mixture of two air parcels becomes denser than either of the original parcels due to evaporation of cloud water. Another criterion is based on the existence of decoupling in the boundary layer. When decoupled, the stratocumulus regime changes to another in which these clouds can still exist together with cumulus. In a LES study, the authors have suggested that a combination of those two criteria can be used to diagnose whether, at a location, the cloud regime corresponds to a well-mixed stratocumulus regime, a shallow cumulus regime, or to a transitional regime where the boundary layer is decoupled. The concept is tested in the framework of an atmospheric general circulation model (GCM). It is found that several outstanding features of disagreement between simulation and observation can be interpreted as misrepresentations of the cloud regimes by the GCM. A novel criterion for switching among regimes is proposed to alleviate the effects of these misrepresentations. (orig.)

  10. Aerosol Indirect effect on Stratocumulus Organization

    Science.gov (United States)

    Zhou, X.; Heus, T.; Kollias, P.

    2015-12-01

    Large-eddy simulations are used to investigate the role of aerosol loading on organized Stratocumulus. We prescribed the cloud droplet number concentration (Nc) and considered it as the proxy for different aerosol loading. While the presence of drizzle amplifies the mesoscale variability as is in Savic-Jovcic and Stevens (JAS, 2008), two noticeable findings are discussed here: First, the scale of marine boundary layer circulation appears to be independent of aerosol loading, suggesting a major role of the turbulence. The precise role of the turbulence in stratocumulus organization is studied by modifying the large scale fluctuations from the LES domain. Second, while it is commonly thought that the whole circulation needs to be represented for robust cloud development, we find that stratocumulus dynamics, including variables like w'w' and w'w'w', are remarkably robust even if large scales are ignored by simply reducing the domain sizes. The only variable that is sensitive to the change of the scale is the amount of cloudiness. Despite their smaller cloud thickness and inhomogeneous macroscopic structure for low Nc, individual drizzling clouds have sizes that are commensurate with circulation scale. We observe an Nc threshold below which stratocumulus is thin enough so that a little decrease of Nc would lead to great change of cloud fraction. The simulated cloud albedo is more sensitive to in-cloud liquid water content than to the amount of cloudiness since the former decreases at least three times faster than the latter due to drizzle. The main impact of drizzle evaporation is observed to keep the sub-cloud layer moist and as a result to extend the lifetime of stratocumulus by a couple of hours.

  11. Quasi-planktonic behavior of foraging top marine predators

    Science.gov (United States)

    Della Penna, Alice; de Monte, Silvia; Kestenare, Elodie; Guinet, Christophe; D'Ovidio, Francesco

    2015-12-01

    Monitoring marine top predators is fundamental for assessing the health and functioning of open ocean ecosystems. Although recently tracking observations have substantially increased, factors determining the horizontal exploration of the ocean by marine predators are still largely unknown, especially at the scale of behavioral switches (1-100 km, days-weeks). It is commonly assumed that the influence of water movement can be neglected for animals capable of swimming faster than the current. Here, we challenge this assumption by combining the use of biologging (GPS and accelerometry), satellite altimetry and in-situ oceanographic data (ADCP and drifting buoys) to investigate the effect of the mesoscale ocean dynamics on a marine predator, the southern elephant seal. A Lagrangian approach reveals that trajectories of elephant seals are characterized by quasi-planktonic bouts where the animals are horizontally drifting. These bouts correspond to periods of increased foraging effort, indicating that in the quasi-planktonic conditions energy is allocated to diving and chasing, rather than in horizontal search of favourable grounds. These results suggest that mesoscale features like eddies and fronts may act as a focal points for trophic interactions not only by bottom-up modulation of nutrient injection, but also by directly entraining horizontal displacements of the upper trophic levels.

  12. Twomey effect in subtropical stratocumulus clouds from UV depolarization lidar

    NARCIS (Netherlands)

    de Graaf, M.; Brown, Jessica; Donovan, D.P.; Nicolae, D.; Makoto, A.; Vassilis, A.; Balis, D.; Behrendt, A.; Comeron, A.; Gibert, F.; Landulfo, E.; McCormick, M.P.; Senff, C.; Veselovskii, I.; Wandinger, U.

    2018-01-01

    Marine stratocumulus clouds are important climate regulators, reflecting sunlight over a dark ocean background. A UV-depolarization lidar on Ascension, a small remote island in the south Atlantic, measured cloud droplet sizes and number concentration using an inversion method based on Monte Carlo

  13. Drizzle production in stratocumulus

    Energy Technology Data Exchange (ETDEWEB)

    Feingold, G.; Frisch, A.S.; Stevens, B.; Cotton, W.R. [Colorado State Univ., Fort Collins, CO (United States)

    1996-04-01

    Although stratocumulus clouds are not prodigious producers of precipitation, the small amounts of drizzle they do produce have an important impact on both cloud macrophysical properties (e.g., spatial coverage, depth and liquid water content) and microphysical properties (e.g., droplet size distributions, effective radii). The radiative effects of stratocumulus are intimately connected to both these macro- and microphysical properties, and it is thus essential that we understand the mechanisms of droplet growth which generate precipitation sized droplets. Drizzle production is closely related to cloud condensation nucleus (CCN) number and size, as well as to cloud dynamics and the ability of clouds to support droplets within their bounds and allow for repeated collision-coalesence cycles. In order to address both the microphysical and dynamical aspects of drizzle formation (and their close coupling), we have adapted a large eddy simulation (LES) model to include explicit (size-resolving) microphysical treatment of the CCN and droplet spectra. By directly calculating processes such as droplet growth by condensation and stochastic collection, evaporation, and sedimentation in the LES framework, we are in a position to elucidate the drizzle formation process.

  14. How large-scale subsidence affects stratocumulus transitions

    Directory of Open Access Journals (Sweden)

    J. J. van der Dussen

    2016-01-01

    Full Text Available Some climate modeling results suggest that the Hadley circulation might weaken in a future climate, causing a subsequent reduction in the large-scale subsidence velocity in the subtropics. In this study we analyze the cloud liquid water path (LWP budget from large-eddy simulation (LES results of three idealized stratocumulus transition cases, each with a different subsidence rate. As shown in previous studies a reduced subsidence is found to lead to a deeper stratocumulus-topped boundary layer, an enhanced cloud-top entrainment rate and a delay in the transition of stratocumulus clouds into shallow cumulus clouds during its equatorwards advection by the prevailing trade winds. The effect of a reduction of the subsidence rate can be summarized as follows. The initial deepening of the stratocumulus layer is partly counteracted by an enhanced absorption of solar radiation. After some hours the deepening of the boundary layer is accelerated by an enhancement of the entrainment rate. Because this is accompanied by a change in the cloud-base turbulent fluxes of moisture and heat, the net change in the LWP due to changes in the turbulent flux profiles is negligibly small.

  15. Future Retention of the Marine Corps Top Performing Aviators

    Science.gov (United States)

    2016-06-10

    balance, and Aviator Continuation Pay. 15. SUBJECT TERMS USMC Aviator Retention, USMC Aviation Manpower, Marine Corps Talent Management , Marine Corps...Wing Aircraft: Includes AH-1, UH-1, and CH-53 platforms. Talent Management : The process through which employers anticipate and meet their needs for...a bias due to his experience as an executive officer responsible for the talent management of company grade WTI aviators. All attempts have been

  16. Dependence of stratocumulus-topped boundary-layer entrainment on cloud-water sedimentation: Impact on global aerosol indirect effect in GISS ModelE3 single column model and global simulations

    Science.gov (United States)

    Ackerman, A. S.; Kelley, M.; Cheng, Y.; Fridlind, A. M.; Del Genio, A. D.; Bauer, S.

    2017-12-01

    Reduction in cloud-water sedimentation induced by increasing droplet concentrations has been shown in large-eddy simulations (LES) and direct numerical simulation (DNS) to enhance boundary-layer entrainment, thereby reducing cloud liquid water path and offsetting the Twomey effect when the overlying air is sufficiently dry, which is typical. Among recent upgrades to ModelE3, the latest version of the NASA Goddard Institute for Space Studies (GISS) general circulation model (GCM), are a two-moment stratiform cloud microphysics treatment with prognostic precipitation and a moist turbulence scheme that includes an option in its entrainment closure of a simple parameterization for the effect of cloud-water sedimentation. Single column model (SCM) simulations are compared to LES results for a stratocumulus case study and show that invoking the sedimentation-entrainment parameterization option indeed reduces the dependence of cloud liquid water path on increasing aerosol concentrations. Impacts of variations of the SCM configuration and the sedimentation-entrainment parameterization will be explored. Its impact on global aerosol indirect forcing in the framework of idealized atmospheric GCM simulations will also be assessed.

  17. Beef customer satisfaction: USDA quality grade and marination effects on consumer evaluations of top round steaks.

    Science.gov (United States)

    Behrends, J M; Goodson, K J; Koohmaraie, M; Shackelford, S D; Wheeler, T L; Morgan, W W; Reagan, J O; Gwartney, B L; Wise, J W; Savell, J W

    2005-03-01

    An in-home beef study evaluated consumer ratings of top round steaks (semimembranosus) as influenced by USDA quality grade (top Choice or high Select), city (Chicago or Philadelphia), consumer segment (beef loyalists = heavy consumers of beef; budget rotators = cost-driven and split meat consumption between beef and chicken; and variety rotators = higher incomes and education and split meat consumption among beef, poultry, and other foods), degree of doneness, cooking method, and marination. Consumers evaluated each steak for overall like, tenderness, juiciness, flavor like, and flavor amount using 10-point scales (1 = dislike extremely, not at all tender, not at all juicy, dislike extremely, and none at all to 10 = like extremely, extremely tender, extremely juicy, like extremely, and an extreme amount of flavor, respectively). Quality grade affected several consumer sensory traits, with top Choice receiving higher (P Consumers in Chicago rated steaks cooked "medium and less" higher for overall like, tenderness, juiciness, flavor like, and flavor amount than those in Philadelphia (city x degree of doneness; P customers in Philadelphia received among the highest scores for overall like, tenderness, juiciness, flavor like, and flavor amount compared with any cooking method used by customers in Chicago (cooking method x city; P customers' satisfaction with top round steaks, and was the sensory trait most highly correlated to overall like, followed by tenderness, flavor amount, and juiciness. Preparation of top round steaks was crucial in consumers' likes and dislikes, and by improving flavor, higher consumer satisfaction may be achieved.

  18. Flat-topped beam transmittance in anisotropic non-Kolmogorov turbulent marine atmosphere

    Science.gov (United States)

    Ata, Yalçın; Baykal, Yahya

    2017-10-01

    Turbulence affects optical propagation, and, as a result, the intensity is attenuated along the path of propagation. The attenuation becomes significant when the turbulence becomes stronger. Transmittance is a measure indicating how much power is collected at the receiver after the optical wave propagates in the turbulent medium. The on-axis transmittance is formulated when a flat-topped optical beam propagates in a marine atmosphere experiencing anisotropic non-Kolmogorov turbulence. Variations in the transmittance are evaluated versus the beam source size, beam number, link distance, power law exponent, anisotropy factor, and structure constant. It is found that larger beam source sizes and beam numbers yield higher transmittance values; however, as the link distance, power law exponent, anisotropy factor, or structure constant increase, transmittance values are lowered. Our results will help in the performance evaluations of optical wireless communication and optical imaging systems operating in a marine atmosphere.

  19. Climate change and marine fisheries: Least developed countries top global index of vulnerability.

    Science.gov (United States)

    Blasiak, Robert; Spijkers, Jessica; Tokunaga, Kanae; Pittman, Jeremy; Yagi, Nobuyuki; Österblom, Henrik

    2017-01-01

    Future impacts of climate change on marine fisheries have the potential to negatively influence a wide range of socio-economic factors, including food security, livelihoods and public health, and even to reshape development trajectories and spark transboundary conflict. Yet there is considerable variability in the vulnerability of countries around the world to these effects. We calculate a vulnerability index of 147 countries by drawing on the most recent data related to the impacts of climate change on marine fisheries. Building on the Intergovernmental Panel on Climate Change framework for vulnerability, we first construct aggregate indices for exposure, sensitivity and adaptive capacity using 12 primary variables. Seven out of the ten most vulnerable countries on the resulting index are Small Island Developing States, and the top quartile of the index includes countries located in Africa (17), Asia (7), North America and the Caribbean (4) and Oceania (8). More than 87% of least developed countries are found within the top half of the vulnerability index, while the bottom half includes all but one of the Organization for Economic Co-operation and Development member states. This is primarily due to the tremendous variation in countries' adaptive capacity, as no such trends are evident from the exposure or sensitivity indices. A negative correlation exists between vulnerability and per capita carbon emissions, and the clustering of states at different levels of development across the vulnerability index suggests growing barriers to meeting global commitments to reducing inequality, promoting human well-being and ensuring sustainable cities and communities. The index provides a useful tool for prioritizing the allocation of climate finance, as well as activities aimed at capacity building and the transfer of marine technology.

  20. Circumpolar dynamics of a marine top-predator track ocean warming rates.

    Science.gov (United States)

    Descamps, Sébastien; Anker-Nilssen, Tycho; Barrett, Robert T; Irons, David B; Merkel, Flemming; Robertson, Gregory J; Yoccoz, Nigel G; Mallory, Mark L; Montevecchi, William A; Boertmann, David; Artukhin, Yuri; Christensen-Dalsgaard, Signe; Erikstad, Kjell-Einar; Gilchrist, H Grant; Labansen, Aili L; Lorentsen, Svein-Håkon; Mosbech, Anders; Olsen, Bergur; Petersen, Aevar; Rail, Jean-Francois; Renner, Heather M; Strøm, Hallvard; Systad, Geir H; Wilhelm, Sabina I; Zelenskaya, Larisa

    2017-09-01

    Global warming is a nonlinear process, and temperature may increase in a stepwise manner. Periods of abrupt warming can trigger persistent changes in the state of ecosystems, also called regime shifts. The responses of organisms to abrupt warming and associated regime shifts can be unlike responses to periods of slow or moderate change. Understanding of nonlinearity in the biological responses to climate warming is needed to assess the consequences of ongoing climate change. Here, we demonstrate that the population dynamics of a long-lived, wide-ranging marine predator are associated with changes in the rate of ocean warming. Data from 556 colonies of black-legged kittiwakes Rissa tridactyla distributed throughout its breeding range revealed that an abrupt warming of sea-surface temperature in the 1990s coincided with steep kittiwake population decline. Periods of moderate warming in sea temperatures did not seem to affect kittiwake dynamics. The rapid warming observed in the 1990s may have driven large-scale, circumpolar marine ecosystem shifts that strongly affected kittiwakes through bottom-up effects. Our study sheds light on the nonlinear response of a circumpolar seabird to large-scale changes in oceanographic conditions and indicates that marine top predators may be more sensitive to the rate of ocean warming rather than to warming itself. © 2017 John Wiley & Sons Ltd.

  1. A single-column model intercomparison on the stratocumulus representation in present-day and future climate

    NARCIS (Netherlands)

    Dal Gesso, S.; Van der Dussen, J.J.; Siebesma, A.P.; De Roode, S.R.; Boutle, I.A.; Kamae, Y.; Roehrig, R.; Vial, J.

    2015-01-01

    Six Single-Column Model (SCM) versions of climate models are evaluated on the basis of their representation of the dependence of the stratocumulus-topped boundary layer regime on the free tropospheric thermodynamic conditions. The study includes two idealized experiments corresponding to the

  2. The Ecology of Coral Reef Top Predators in the Papahānaumokuākea Marine National Monument

    Directory of Open Access Journals (Sweden)

    Jonathan J. Dale

    2011-01-01

    Full Text Available Coral reef habitats in the Papahānaumokuākea Marine National Monument (PMNM are characterized by abundant top-level predators such as sharks and jacks. The predator assemblage is dominated both numerically and in biomass by giant trevally (Caranx ignobilis and Galapagos sharks (Carcharhinus galapagensis. A lower diversity of predatory teleosts, particularly groupers and snappers, distinguishes the PMNM from other remote, unfished atolls in the Pacific. Most coral reef top predators are site attached to a “home” atoll, but move extensively within these atolls. Abundances of the most common sharks and jacks are highest in atoll fore reef habitats. Top predators within the PMNM forage on a diverse range of prey and exert top-down control over shallow-water reef fish assemblages. Ecological models suggest ecosystem processes may be most impacted by top predators through indirect effects of predation. Knowledge gaps are identified to guide future studies of top predators in the PMNM.

  3. Responses of two marine top predators to an offshore wind farm.

    Science.gov (United States)

    Vallejo, Gillian C; Grellier, Kate; Nelson, Emily J; McGregor, Ross M; Canning, Sarah J; Caryl, Fiona M; McLean, Nancy

    2017-11-01

    Quantifying the likely effects of offshore wind farms on wildlife is fundamental before permission for development can be granted by any Determining Authority. The effects on marine top predators from displacement from important habitat are key concerns during offshore wind farm construction and operation. In this respect, we present evidence for no significant displacement from a UK offshore wind farm for two broadly distributed species of conservation concern: common guillemot ( Uria aalge ) and harbor porpoise ( Phocoena phocoena ). Data were collected during boat-based line transect surveys across a 360 km 2 study area that included the Robin Rigg offshore wind farm. Surveys were conducted over 10 years across the preconstruction, construction, and operational phases of the development. Changes in guillemot and harbor porpoise abundance and distribution in response to offshore wind farm construction and operation were estimated using generalized mixed models to test for evidence of displacement. Both common guillemot and harbor porpoise were present across the Robin Rigg study area throughout all three development phases. There was a significant reduction in relative harbor porpoise abundance both within and surrounding the Robin Rigg offshore wind farm during construction, but no significant difference was detected between the preconstruction and operational phases. Relative common guillemot abundance remained similar within the Robin Rigg offshore wind farm across all development phases. Offshore wind farms have the potential to negatively affect wildlife, but further evidence regarding the magnitude of effect is needed. The empirical data presented here for two marine top predators provide a valuable addition to the evidence base, allowing future decision making to be improved by reducing the uncertainty of displacement effects and increasing the accuracy of impact assessments.

  4. Direct determination of radon in the marine troposphere

    International Nuclear Information System (INIS)

    Burtner, D.R.; Kay, J.G.

    1990-01-01

    222 Rn concentrations have been determined within and directly above the top of the marine boundary layer over the Eastern Pacific Ocean about 350 miles off the California coast. This was part of a multi-investigator, comprehensive study of the chemistry and dynamics of the marine stratocumulus conducted in July and August, 1985. Samples were collected using an aircraft, the Electra, in cooperation with National Center for Atmospheric Research. Concentrations of radon, determined by the Lucas cell method using charcoal absorption techniques, ranged from a low of about 12 atoms of radon per liter of air to a high of about 430 atoms/l. Entrainment rates across the top of the marine boundary layer have been determined from these measurements. Correlation of radon concentrations with other chemical species is suggested in certain cases

  5. The radiation budget of stratocumulus clouds measured by tethered balloon instrumentation: Variability of flux measurements

    Science.gov (United States)

    Duda, David P.; Stephens, Graeme L.; Cox, Stephen K.

    1990-01-01

    Measurements of longwave and shortwave radiation were made using an instrument package on the NASA tethered balloon during the FIRE Marine Stratocumulus experiment. Radiation data from two pairs of pyranometers were used to obtain vertical profiles of the near-infrared and total solar fluxes through the boundary layer, while a pair of pyrgeometers supplied measurements of the longwave fluxes in the cloud layer. The radiation observations were analyzed to determine heating rates and to measure the radiative energy budget inside the stratocumulus clouds during several tethered balloon flights. The radiation fields in the cloud layer were also simulated by a two-stream radiative transfer model, which used cloud optical properties derived from microphysical measurements and Mie scattering theory.

  6. Stratocumulus to Cumulus Transition by Drizzle

    Science.gov (United States)

    Yamaguchi, Takanobu; Feingold, Graham; Kazil, Jan

    2017-10-01

    The stratocumulus to cumulus transition (SCT) is typically considered to be a slow, multiday process, caused primarily by dry air entrainment associated with overshooting cumulus, with minor influence of drizzle. This study revisits the role of drizzle in the SCT with large eddy simulations coupled with a two-moment bulk microphysics scheme that includes a budget on aerosol (Na) and cloud droplet number concentrations (Nc). We show a strong precipitation-induced modulation of the SCT by drizzle initiated in penetrative cumulus under stratocumulus. Lagrangian SCT simulations are initiated with various, moderate Na (100-250 cm-3), which produce little to no drizzle from the stratocumulus. As expected, drizzle formation in cumuli is regulated by cloud depth and Nc, with stronger dependence on cloud depth, so that, for the current case, drizzle is generated in all simulations once cumulus clouds become sufficiently deep. The drizzle generated in the cumuli washes out stratocumulus cloud water and much of the aerosol, and a cumulus state appears for approximately 10 h. With additional simulations with a fixed Nc (100 cm-3), we show that prediction of Nc is necessary for this fast SCT since it is a result of a positive feedback of collision-coalescence-induced aerosol depletion that enhances drizzle formation. A fixed Nc does not permit this feedback, and thus results in weak influence of drizzle on the SCT. Simulations with fixed droplet concentrations that bracket the time varying aerosol/drop concentrations are therefore not representative of the role of drizzle in the SCT.

  7. Foraging strategy switch of a top marine predator according to seasonal resource differences

    Directory of Open Access Journals (Sweden)

    Malcolm Daniel O'Toole

    2015-04-01

    Full Text Available The spatio-temporal variability in marine resources influences the foraging behaviour and success of top marine predators. However, little is known about the links between these animals and ocean productivity, specifically, how plankton density influences their foraging behaviour. Southern elephant seals (Mirounga leonina have two annual at-sea foraging trips: a two month post-breeding foraging trip (Nov – Jan that coincides with elevated summer productivity; and an eight month post-moulting foraging trip (Feb – Oct over winter, when productivity is low. Physical parameters are often used to describe seal habitat, whereas information about important biological parameters is lacking. We used electronic tags deployed on elephant seals during both trips to determine their movement and foraging behaviour. The tags also recorded light, which measured the bio-optical properties of the water column, the bulk of which is presumably influenced by phytoplankton. We investigated the relationship between plankton density and seal foraging behaviour; comparing trends between summer and winter trips. We found a positive relationship between plankton density and foraging behaviour, which did not vary seasonally. We propose that profitable concentrations of seal prey are more likely to coincide with planktonic aggregations, but we also acknowledge that trophic dynamics may shift in response to seasonal trends in productivity. Seal prey (mid-trophic level and plankton (lower-trophic level are expected to overlap in space and time during summer trips when peak phytoplankton blooms occur. In contrast, aggregated patches of lower trophic levels are likely to be more dispersed during winter trips when plankton density is considerably lower and heterogeneous. These results show that southern elephant seals are able to exploit prey resources in different ways throughout the year as demonstrated by the variation observed between seal foraging behaviour and trophic

  8. Low Density of Top Predators (Seabirds and Marine Mammals in the High Arctic Pack Ice

    Directory of Open Access Journals (Sweden)

    Claude R. Joiris

    2016-01-01

    Full Text Available The at-sea distribution of top predators, seabirds and marine mammals, was determined in the high Arctic pack ice on board the icebreaker RV Polarstern in July to September 2014. In total, 1,620 transect counts were realised, lasting 30 min each. The five most numerous seabird species represented 74% of the total of 15,150 individuals registered: kittiwake Rissa tridactyla, fulmar Fulmarus glacialis, puffin Fratercula arctica, Ross’s gull Rhodostethia rosea, and little auk Alle alle. Eight cetacean species were tallied for a total of 330 individuals, mainly white-beaked dolphin Lagenorhynchus albirostris and fin whale Balaenoptera physalus. Five pinniped species were represented by a total of 55 individuals and the polar bear Ursus maritimus was represented by 12 individuals. Four main geographical zones were identified: from Tromsø to the outer marginal ice zone (OMIZ, the Arctic pack ice (close pack ice, CPI, the end of Lomonosov Ridge off Siberia, and the route off Siberia and northern Norway. Important differences were detected between zones, both in species composition and in individual abundance. Low numbers of species and high proportion of individuals for some of them can be considered to reflect very low biodiversity. Numbers encountered in zones 2 to 4 were very low in comparison with other European Arctic seas. The observed differences showed strong patterns.

  9. Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers

    Directory of Open Access Journals (Sweden)

    Junya Uchida

    2010-12-01

    Full Text Available In marine stratocumulus-capped boundary layers under strong inversions, the timescale for thermodynamic adjustment is roughly a day, much shorter than the multiday timescale for inversion height adjustment. Slow-manifold analysis is introduced to exploit this timescale separation when boundary layer air columns experience only slow changes in their boundary conditions. Its essence is that the thermodynamic structure of the boundary layer remains approximately slaved to its inversion height and the instantaneous boundary conditions; this slaved structure determines the entrainment rate and hence the slow evolution of the inversion height. Slow-manifold analysis is shown to apply to mixed-layer model and large-eddy simulations of an idealized nocturnal stratocumulus- capped boundary layer; simulations with different initial inversion heights collapse onto single relationships of cloud properties with inversion height. Depending on the initial inversion height, the simulations evolve toward a shallow thin-cloud boundary layer or a deep, well-mixed thick cloud boundary layer. In the large-eddy simulations, these evolutions occur on two separate slow manifolds (one of which becomes unstable if cloud droplet concentration is reduced. Applications to analysis of stratocumulus observations and to pockets of open cells and ship tracks are proposed.

  10. Effects of biomass smoke from southern Africa on stratocumulus over southeastern Atlantic Ocean based on satellite observations and WRF-Chem model simulations

    Science.gov (United States)

    Lu, Z.; Liu, X.; Zhang, Z.; Zhao, C.; Meyer, K.; Rajapakshe, C.; Wu, C.; Yang, Z.; Penner, J.

    2017-12-01

    Each year, large amount of biomass burning (BB) aerosols are emitted over southern Africa, and transported by the predominant circulation to the southeastern Atlantic Ocean (SEA), where they overly and potentially interact with the semi-permanent stratocumulus deck in the marine boundary layer (MBL). Many previous studies suggested that the aerosol plumes are well separated from the MBL clouds, and only focused on the radiative effects of BB aerosols (direct + semi-direct radiative effects); however, as shown in several recent satellite observational studies, BB aerosols are able to be frequently entrained into the underlying clouds, function as cloud condensation nuclei (CCN), and potentially cause microphysical effects. Based on satellite observations from CATS, we found that the mixing frequencies between above-cloud aerosols and MBL clouds are very high ( 50%) over both coastal and remote regions, suggesting that BB aerosols may likely contact MBL cloud top and function as CCN quickly after they are transported over SEA. Despite the potential importance of the microphysical effect of BB aerosols over SEA, its magnitude is not fully assessed by modeling studies. In this study, we employ WRF-Chem model to study the impacts of BB aerosols on MBL stratocumulus clouds over SEA during the fire season of 2014. By designing three cases, we are able to quantitatively determine the relative importance of microphysical and radiative effects of BB aerosols. Our modeling results show that, by serving as CCN, BB aerosols are able to alter cloud properties of stratocumulus (e.g. higher cloud droplet number concentration [CDNC], higher cloud liquid water path [LWP], and larger cloud fraction [CF] before noon) and exert significant cooling effect at TOA (-8.05 Wm-2) over SEA. The cooling is primarily caused by higher CDNC (the Twomey effect), and secondarily by the changes in LWP and CF (the cloud lifetime effect). The semi-direct effect estimated in this study is smaller in

  11. Can Static Habitat Protection Encompass Critical Areas for Highly Mobile Marine Top Predators? Insights from Coastal East Africa.

    Directory of Open Access Journals (Sweden)

    Sergi Pérez-Jorge

    Full Text Available Along the East African coast, marine top predators are facing an increasing number of anthropogenic threats which requires the implementation of effective and urgent conservation measures to protect essential habitats. Understanding the role that habitat features play on the marine top predator' distribution and abundance is a crucial step to evaluate the suitability of an existing Marine Protected Area (MPA, originally designated for the protection of coral reefs. We developed species distribution models (SDM on the IUCN data deficient Indo-Pacific bottlenose dolphin (Tursiops aduncus in southern Kenya. We followed a comprehensive ecological modelling approach to study the environmental factors influencing the occurrence and abundance of dolphins while developing SDMs. Through the combination of ensemble prediction maps, we defined recurrent, occasional and unfavourable habitats for the species. Our results showed the influence of dynamic and static predictors on the dolphins' spatial ecology: dolphins may select shallow areas (5-30 m, close to the reefs (< 500 m and oceanic fronts (< 10 km and adjacent to the 100 m isobath (< 5 km. We also predicted a significantly higher occurrence and abundance of dolphins within the MPA. Recurrent and occasional habitats were identified on large percentages on the existing MPA (47% and 57% using presence-absence and abundance models respectively. However, the MPA does not adequately encompass all occasional and recurrent areas and within this context, we propose to extend the MPA to incorporate all of them which are likely key habitats for the highly mobile species. The results from this study provide two key conservation and management tools: (i an integrative habitat modelling approach to predict key marine habitats, and (ii the first study evaluating the effectiveness of an existing MPA for marine mammals in the Western Indian Ocean.

  12. Evaluation of stratocumulus cloud prediction in the Met Office forecast model during VOCALS-REx

    Directory of Open Access Journals (Sweden)

    S. J. Abel

    2010-11-01

    Full Text Available Observations in the subtropical southeast Pacific obtained during the VOCALS-REx field experiment are used to evaluate the representation of stratocumulus cloud in the Met Office forecast model and to identify key areas where model biases exist. Marked variations in the large scale structure of the cloud field were observed during the experiment on both day-to-day and on diurnal timescales. In the remote maritime region the model is shown to have a good representation of synoptically induced variability in both cloud cover and marine boundary layer depth. Satellite observations show a strong diurnal cycle in cloud fraction and liquid water path in the stratocumulus with enhanced clearances of the cloud deck along the Chilean and Peruvian coasts on certain days. The model accurately simulates the phase of the diurnal cycle but is unable to capture the coastal clearing of cloud. Observations along the 20° S latitude line show a gradual increase in the depth of the boundary layer away from the coast. This trend is well captured by the model (typical low bias of 200 m although significant errors exist at the coast where the model marine boundary layer is too shallow and moist. Drizzle in the model responds to changes in liquid water path in a manner that is consistent with previous ship-borne observations in the region although the intensity of this drizzle is likely to be too high, particularly in the more polluted coastal region where higher cloud droplet number concentrations are typical. Another mode of variability in the cloud field that the model is unable to capture are regions of pockets of open cellular convection embedded in the overcast stratocumulus deck and an example of such a feature that was sampled during VOCALS-REx is shown.

  13. Impacts of solar-absorbing aerosol layers on the transition of stratocumulus to trade cumulus clouds

    Directory of Open Access Journals (Sweden)

    X. Zhou

    2017-10-01

    Full Text Available The effects of an initially overlying layer of solar-absorbing aerosol on the transition of stratocumulus to trade cumulus clouds are examined using large-eddy simulations. For lightly drizzling cloud the transition is generally hastened, resulting mainly from increased cloud droplet number concentration (Nc induced by entrained aerosol. The increased Nc slows sedimentation of cloud droplets and shortens their relaxation time for diffusional growth, both of which accelerate entrainment of overlying air and thereby stratocumulus breakup. However, the decrease in albedo from cloud breakup is more than offset by redistributing cloud water over a greater number of droplets, such that the diurnal-average shortwave forcing at the top of the atmosphere is negative. The negative radiative forcing is enhanced by sizable longwave contributions, which result from the greater cloud breakup and a reduced boundary layer height associated with aerosol heating. A perturbation of moisture instead of aerosol aloft leads to a greater liquid water path and a more gradual transition. Adding absorbing aerosol to that atmosphere results in substantial reductions in liquid water path (LWP and cloud cover that lead to positive shortwave and negative longwave forcings on average canceling each other. Only for heavily drizzling clouds is the breakup delayed, as inhibition of precipitation overcomes cloud water loss from enhanced entrainment. Considering these simulations as an imperfect proxy for biomass burning plumes influencing Namibian stratocumulus, we expect regional indirect plus semi-direct forcings to be substantially negative to negligible at the top of the atmosphere, with its magnitude sensitive to background and perturbation properties.

  14. Shellfish dredging pushes a flexible avian top predator out of a marine protected area

    NARCIS (Netherlands)

    van Gils, Jan A.; Piersma, Theunis; Dekinga, Anne; Spaans, Bernard; Kraan, Casper

    2006-01-01

    There is a widespread concern about the direct and indirect effects of industrial fisheries; this concern is particularly pertinent for so-called "marine protected areas" (MPAs), which should be safeguarded by national and international law. The intertidal flats of the Dutch Wadden Sea are a State

  15. Shellfish dredging pushes a flexible avian top predator out of a marine protected area

    NARCIS (Netherlands)

    Van Gils, J.A.; Piersma, T.; Dekinga, A.; Spaans, B.; Kraan, C.

    2006-01-01

    There is a widespread concern about the direct and indirect effects of industrial fisheries; this concern is particularly pertinent for so-called “marine protected areas” (MPAs), which should be safeguarded by national and international law. The intertidal flats of the Dutch Wadden Sea are a State

  16. Network approach to patterns in stratocumulus clouds

    Science.gov (United States)

    Glassmeier, Franziska; Feingold, Graham

    2017-10-01

    Stratocumulus clouds (Sc) have a significant impact on the amount of sunlight reflected back to space, with important implications for Earth’s climate. Representing Sc and their radiative impact is one of the largest challenges for global climate models. Sc fields self-organize into cellular patterns and thus lend themselves to analysis and quantification in terms of natural cellular networks. Based on large-eddy simulations of Sc fields, we present a first analysis of the geometric structure and self-organization of Sc patterns from this network perspective. Our network analysis shows that the Sc pattern is scale-invariant as a consequence of entropy maximization that is known as Lewis’s Law (scaling parameter: 0.16) and is largely independent of the Sc regime (cloud-free vs. cloudy cell centers). Cells are, on average, hexagonal with a neighbor number variance of about 2, and larger cells tend to be surrounded by smaller cells, as described by an Aboav-Weaire parameter of 0.9. The network structure is neither completely random nor characteristic of natural convection. Instead, it emerges from Sc-specific versions of cell division and cell merging that are shaped by cell expansion. This is shown with a heuristic model of network dynamics that incorporates our physical understanding of cloud processes.

  17. Marine cloud brightening

    OpenAIRE

    Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John

    2012-01-01

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could—subject to satisfactory resolution of technical and scientific problems identi...

  18. How accurately can we estimate energetic costs in a marine top predator, the king penguin?

    Science.gov (United States)

    Halsey, Lewis G; Fahlman, Andreas; Handrich, Yves; Schmidt, Alexander; Woakes, Anthony J; Butler, Patrick J

    2007-01-01

    King penguins (Aptenodytes patagonicus) are one of the greatest consumers of marine resources. However, while their influence on the marine ecosystem is likely to be significant, only an accurate knowledge of their energy demands will indicate their true food requirements. Energy consumption has been estimated for many marine species using the heart rate-rate of oxygen consumption (f(H) - V(O2)) technique, and the technique has been applied successfully to answer eco-physiological questions. However, previous studies on the energetics of king penguins, based on developing or applying this technique, have raised a number of issues about the degree of validity of the technique for this species. These include the predictive validity of the present f(H) - V(O2) equations across different seasons and individuals and during different modes of locomotion. In many cases, these issues also apply to other species for which the f(H) - V(O2) technique has been applied. In the present study, the accuracy of three prediction equations for king penguins was investigated based on validity studies and on estimates of V(O2) from published, field f(H) data. The major conclusions from the present study are: (1) in contrast to that for walking, the f(H) - V(O2) relationship for swimming king penguins is not affected by body mass; (2) prediction equation (1), log(V(O2) = -0.279 + 1.24log(f(H) + 0.0237t - 0.0157log(f(H)t, derived in a previous study, is the most suitable equation presently available for estimating V(O2) in king penguins for all locomotory and nutritional states. A number of possible problems associated with producing an f(H) - V(O2) relationship are discussed in the present study. Finally, a statistical method to include easy-to-measure morphometric characteristics, which may improve the accuracy of f(H) - V(O2) prediction equations, is explained.

  19. Temperature regulation of marine heterotrophic prokaryotes increases latitudinally as a breach between bottom-up and top-down controls

    KAUST Repository

    Moran, Xose Anxelu G.

    2017-04-19

    Planktonic heterotrophic prokaryotes make up the largest living biomass and process most organic matter in the ocean. Determining when and where the biomass and activity of heterotrophic prokaryotes are controlled by resource availability (bottom-up), predation and viral lysis (top-down) or temperature will help in future carbon cycling predictions. We conducted an extensive survey across subtropical and tropical waters of the Atlantic, Indian and Pacific Oceans during the Malaspina 2010 Global Circumnavigation Expedition and assessed indices for these three types of controls at 109 stations (mostly from the surface to 4000 m depth). Temperature control was approached by the apparent activation energy in eV (ranging from 0.46 to 3.41), bottom-up control by the slope of the log-log relationship between biomass and production rate (ranging from -0.12 to 1.09) and top-down control by an index that considers the relative abundances of heterotrophic nanoflagellates and viruses (ranging from 0.82 to 4.83). We conclude that temperature becomes dominant (i.e. activation energy >1.5 eV) within a narrow window of intermediate values of bottom-up (0.3-0.6) and top-down 0.8-1.2) controls. A pervasive latitudinal pattern of decreasing temperature regulation towards the Equator, regardless of the oceanic basin, suggests that the impact of global warming on marine microbes and their biogeochemical function will be more intense at higher latitudes. Our analysis predicts that 1°C ocean warming will result in increased biomass of heterotrophic prokaryoplankton only in waters with <26°C of mean annual surface temperature. This article is protected by copyright. All rights reserved.

  20. Shellfish dredging pushes a flexible avian top predator out of a marine protected area.

    Directory of Open Access Journals (Sweden)

    Jan A van Gils

    2006-11-01

    Full Text Available There is a widespread concern about the direct and indirect effects of industrial fisheries; this concern is particularly pertinent for so-called "marine protected areas" (MPAs, which should be safeguarded by national and international law. The intertidal flats of the Dutch Wadden Sea are a State Nature Monument and are protected under the Ramsar convention and the European Union's Habitat and Birds Directives. Until 2004, the Dutch government granted permission for ~75% of the intertidal flats to be exploited by mechanical dredgers for edible cockles (Cerastoderma edule. Here we show that dredged areas belonged to the limited area of intertidal flats that were of sufficient quality for red knots (Calidris canutus islandica, a long-distance migrant molluscivore specialist, to feed. Dredging led to relatively lower settlement rates of cockles and also reduced their quality (ratio of flesh to shell. From 1998 to 2002, red knots increased gizzard mass to compensate for a gradual loss in shellfish quality, but this compensation was not sufficient and led to decreases in local survival. Therefore, the gradual destruction of the necessary intertidal resources explains both the loss of red knots from the Dutch Wadden Sea and the decline of the European wintering population. This study shows that MPAs that do not provide adequate protection from fishing may fail in their conservation objectives.

  1. A comparative study of the response of modeled non-drizzling stratocumulus to meteorological and aerosol perturbations

    Directory of Open Access Journals (Sweden)

    J. L. Petters

    2013-03-01

    Full Text Available The impact of changes in aerosol and cloud droplet concentration (Na and Nd on the radiative forcing of stratocumulus-topped boundary layers (STBLs has been widely studied. How these impacts compare to those due to variations in meteorological context has not been investigated in a systematic fashion for non-drizzling overcast stratocumulus. In this study we examine the impact of observed variations in meteorological context and aerosol state on daytime, non-drizzling overcast stratiform evolution, and determine how resulting changes in cloud properties compare. Using large-eddy simulation (LES we create a model base case of daytime southeast Pacific coastal stratocumulus, spanning a portion of the diurnal cycle (early morning to near noon and constrained by observations taken during the VOCALS (VAMOS Ocean-Atmosphere-Land Study field campaign. We perturb aerosol and meteorological properties around this base case to investigate the stratocumulus response. We determine perturbations in the cloud top jumps in potential temperature θ and total water mixing ratio qt from ECMWF Re-analysis Interim data, and use a set of Nd values spanning the observable range. To determine the cloud response to these meteorological and aerosol perturbations, we compute changes in liquid water path (LWP, bulk optical depth (τ and cloud radiative forcing (CRF. We find that realistic variations in the thermodynamic jump properties can elicit a response in the cloud properties of τ and shortwave (SW CRF that are on the same order of magnitude as the response found due to realistic changes in aerosol state (i.e Nd. In response to increases in Nd, the cloud layer in the base case thinned due to increases in evaporative cooling and entrainment rate. This cloud thinning somewhat mitigates the increase in τ resulting from increases in Nd. On the other hand, variations in θ and qt jumps did not substantially modify Nd. The cloud layer thickens in response to an increase

  2. Aerosol characteristics in the entrainment interface layer in relation to the marine boundary layer and free troposphere

    Directory of Open Access Journals (Sweden)

    H. Dadashazar

    2018-02-01

    Full Text Available This study uses airborne data from two field campaigns off the California coast to characterize aerosol size distribution characteristics in the entrainment interface layer (EIL, a thin and turbulent layer above marine stratocumulus cloud tops, which separates the stratocumulus-topped boundary layer (STBL from the free troposphere (FT. The vertical bounds of the EIL are defined in this work based on considerations of buoyancy and turbulence using thermodynamic and dynamic data. Aerosol number concentrations are examined from three different probes with varying particle diameter (Dp ranges: > 3 nm, > 10 nm, and 0.11–3.4 µm. Relative to the EIL and FT layers, the sub-cloud (SUB layer exhibited lower aerosol number concentrations and higher surface area concentrations. High particle number concentrations between 3 and 10 nm in the EIL are indicative of enhanced nucleation, assisted by high actinic fluxes, cool and moist air, and much lower surface area concentrations than the STBL. Slopes of number concentration versus altitude in the EIL were correlated with the particle number concentration difference between the SUB and lower FT layers. The EIL aerosol size distribution was influenced by varying degrees from STBL aerosol versus subsiding FT aerosol depending on the case examined. These results emphasize the important role of the EIL in influencing nucleation and aerosol–cloud–climate interactions.

  3. Aerosol characteristics in the entrainment interface layer in relation to the marine boundary layer and free troposphere

    Science.gov (United States)

    Dadashazar, Hossein; Braun, Rachel A.; Crosbie, Ewan; Chuang, Patrick Y.; Woods, Roy K.; Jonsson, Haflidi H.; Sorooshian, Armin

    2018-02-01

    This study uses airborne data from two field campaigns off the California coast to characterize aerosol size distribution characteristics in the entrainment interface layer (EIL), a thin and turbulent layer above marine stratocumulus cloud tops, which separates the stratocumulus-topped boundary layer (STBL) from the free troposphere (FT). The vertical bounds of the EIL are defined in this work based on considerations of buoyancy and turbulence using thermodynamic and dynamic data. Aerosol number concentrations are examined from three different probes with varying particle diameter (Dp) ranges: > 3 nm, > 10 nm, and 0.11-3.4 µm. Relative to the EIL and FT layers, the sub-cloud (SUB) layer exhibited lower aerosol number concentrations and higher surface area concentrations. High particle number concentrations between 3 and 10 nm in the EIL are indicative of enhanced nucleation, assisted by high actinic fluxes, cool and moist air, and much lower surface area concentrations than the STBL. Slopes of number concentration versus altitude in the EIL were correlated with the particle number concentration difference between the SUB and lower FT layers. The EIL aerosol size distribution was influenced by varying degrees from STBL aerosol versus subsiding FT aerosol depending on the case examined. These results emphasize the important role of the EIL in influencing nucleation and aerosol-cloud-climate interactions.

  4. Large Eddy Simulation of the Diurnal Cycle in Southeast Pacific Stratocumulus

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, P; Bretherton, C

    2008-03-03

    This paper describes a series of 6 day large eddy simulations of a deep, sometimes drizzling stratocumulus-topped boundary layer based on forcings from the East Pacific Investigation of Climate (EPIC) 2001 field campaign. The base simulation was found to reproduce the observed mean boundary layer properties quite well. The diurnal cycle of liquid water path was also well captured, although good agreement appears to result partially from compensating errors in the diurnal cycles of cloud base and cloud top due to overentrainment around midday. At other times of the day, entrainment is found to be proportional to the vertically-integrated buoyancy flux. Model stratification matches observations well; turbulence profiles suggest that the boundary layer is always at least somewhat decoupled. Model drizzle appears to be too sensitive to liquid water path and subcloud evaporation appears to be too weak. Removing the diurnal cycle of subsidence had little effect on simulated cloud albedo. Simulations with changed droplet concentration and drizzle susceptibility showed large liquid water path differences at night, but differences were quite small at midday. Droplet concentration also had a significant impact on entrainment, primarily through droplet sedimentation feedback rather than through drizzle processes.

  5. Moisture and dynamical interactions maintaining decoupled Arctic mixed-phase stratocumulus in the presence of a humidity inversion

    Directory of Open Access Journals (Sweden)

    A. Solomon

    2011-10-01

    Full Text Available Observations suggest that processes maintaining subtropical and Arctic stratocumulus differ, due to the different environments in which they occur. For example, specific humidity inversions (specific humidity increasing with height are frequently observed to occur near cloud top coincident with temperature inversions in the Arctic, while they do not occur in the subtropics. In this study we use nested LES simulations of decoupled Arctic Mixed-Phase Stratocumulus (AMPS clouds observed during the DOE Atmospheric Radiation Measurement Program's Indirect and SemiDirect Aerosol Campaign (ISDAC to analyze budgets of water components, potential temperature, and turbulent kinetic energy. These analyses quantify the processes that maintain decoupled AMPS, including the role of humidity inversions. Key structural features include a shallow upper entrainment zone at cloud top that is located within the temperature and humidity inversions, a mixed layer driven by cloud-top cooling that extends from the base of the upper entrainment zone to below cloud base, and a lower entrainment zone at the base of the mixed layer. The surface layer below the lower entrainment zone is decoupled from the cloud mixed-layer system. Budget results show that cloud liquid water is maintained in the upper entrainment zone near cloud top (within a temperature and humidity inversion due to a down gradient transport of water vapor by turbulent fluxes into the cloud layer from above and direct condensation forced by radiative cooling. Liquid water is generated in the updraft portions of the mixed-layer eddies below cloud top by buoyant destabilization. These processes cause at least 20% of the cloud liquid water to extend into the inversion. The redistribution of water vapor from the top of the humidity inversion to its base maintains the cloud layer, while the mixed layer-entrainment zone system is continually losing total water. In this decoupled system, the humidity inversion is

  6. Marine cloud brightening

    Science.gov (United States)

    Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Phillip; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Rob

    2012-01-01

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could—subject to satisfactory resolution of technical and scientific problems identified herein—have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud–albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action

  7. Marine Cloud Brightening

    Energy Technology Data Exchange (ETDEWEB)

    Latham, John; Bower, Keith; Choularton, Tom; Coe, H.; Connolly, P.; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Philip J.; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Robert

    2012-09-07

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could - subject to satisfactory resolution of technical and scientific problems identified herein - have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seedparticle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

  8. Marine cloud brightening.

    Science.gov (United States)

    Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Phillip; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Rob

    2012-09-13

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could-subject to satisfactory resolution of technical and scientific problems identified herein-have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

  9. How thermodynamic environments control stratocumulus microphysics and interactions with aerosols

    International Nuclear Information System (INIS)

    Andersen, Hendrik; Cermak, Jan

    2015-01-01

    Aerosol–cloud interactions are central to climate system changes and depend on meteorological conditions. This study identifies distinct thermodynamic regimes and proposes a conceptual framework for interpreting aerosol effects. In the analysis, ten years (2003–2012) of daily satellite-derived aerosol and cloud products are combined with reanalysis data to identify factors controlling Southeast Atlantic stratocumulus microphysics. Considering the seasonal influence of aerosol input from biomass burning, thermodynamic environments that feature contrasting microphysical cloud properties and aerosol–cloud relations are classified. While aerosol impact is stronger in unstable environments, it is mostly confined to situations with low aerosol loading (aerosol index AI ≲ 0.15), implying a saturation of aerosol effects. Situations with high aerosol loading are associated with weaker, seasonally contrasting aerosol-droplet size relationships, likely caused by thermodynamically induced processes and aerosol swelling. (letter)

  10. Entrainment Zone Characteristics and Entrainment Rates in Cloud-Topped Boundary Layers from DYCOMS-II

    Science.gov (United States)

    2012-03-01

    Malinowski , J. L. Brenguier, and F. Burnet, 2005: Holes and entrainment in stratocumulus. J. Atmos. Sci., 62, 443–459. Glickman, T. S...of the Entrainment Zone in Cloud-topped Boundary Layers. Department of Meteorology, NPS, 93 pp. Krzysztof, Haman E., S. P. Malinowski , M. J

  11. Response of rocky reef top predators (Serranidae: Epinephelinae in and around marine protected areas in the Western Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Carlos Werner Hackradt

    Full Text Available Groupers species are extremely vulnerable to overfishing and many species are threatened worldwide. In recent decades, Mediterranean groupers experienced dramatic population declines. Marine protected areas (MPAs can protect populations inside their boundaries and provide individuals to adjacent fishing areas through the process of spillover and larval export. This study aims to evaluate the effectiveness of six marine reserves in the Western Mediterranean Sea to protect the populations of three species of grouper, Epinephelus marginatus, Epinephelus costae and Mycteroperca rubra, and to understand in which circumstances MPAs are able to export biomass to neighbouring areas. All the studied MPAs, except one where no grouper was observed, were able to maintain high abundance, biomass and mean weight of groupers. Size classes were more evenly distributed inside than outside MPAs. In two reserves, biomass gradients could be detected through the boundaries of the reserve as an indication of spillover. In some cases, habitat structure appeared to exert a great influence on grouper abundance, biomass and mean individual weight, influencing the gradient shape. Because groupers are generally sedentary animals with a small home range, we suggest that biomass gradients could only occur where groupers attain sufficient abundance inside MPA limits, indicating a strongly density-dependent process.

  12. Combining Methods to Describe Important Marine Habitats for Top Predators: Application to Identify Biological Hotspots in Tropical Waters.

    Science.gov (United States)

    Thiers, Laurie; Louzao, Maite; Ridoux, Vincent; Le Corre, Matthieu; Jaquemet, Sébastien; Weimerskirch, Henri

    2014-01-01

    In tropical waters resources are usually scarce and patchy, and predatory species generally show specific adaptations for foraging. Tropical seabirds often forage in association with sub-surface predators that create feeding opportunities by bringing prey close to the surface, and the birds often aggregate in large multispecific flocks. Here we hypothesize that frigatebirds, a tropical seabird adapted to foraging with low energetic costs, could be a good predictor of the distribution of their associated predatory species, including other seabirds (e.g. boobies, terns) and subsurface predators (e.g., dolphins, tunas). To test this hypothesis, we compared distribution patterns of marine predators in the Mozambique Channel based on a long-term dataset of both vessel- and aerial surveys, as well as tracking data of frigatebirds. By developing species distribution models (SDMs), we identified key marine areas for tropical predators in relation to contemporaneous oceanographic features to investigate multi-species spatial overlap areas and identify predator hotspots in the Mozambique Channel. SDMs reasonably matched observed patterns and both static (e.g. bathymetry) and dynamic (e.g. Chlorophyll a concentration and sea surface temperature) factors were important explaining predator distribution patterns. We found that the distribution of frigatebirds included the distributions of the associated species. The central part of the channel appeared to be the best habitat for the four groups of species considered in this study (frigatebirds, brown terns, boobies and sub-surface predators).

  13. Combining Methods to Describe Important Marine Habitats for Top Predators: Application to Identify Biological Hotspots in Tropical Waters.

    Directory of Open Access Journals (Sweden)

    Laurie Thiers

    Full Text Available In tropical waters resources are usually scarce and patchy, and predatory species generally show specific adaptations for foraging. Tropical seabirds often forage in association with sub-surface predators that create feeding opportunities by bringing prey close to the surface, and the birds often aggregate in large multispecific flocks. Here we hypothesize that frigatebirds, a tropical seabird adapted to foraging with low energetic costs, could be a good predictor of the distribution of their associated predatory species, including other seabirds (e.g. boobies, terns and subsurface predators (e.g., dolphins, tunas. To test this hypothesis, we compared distribution patterns of marine predators in the Mozambique Channel based on a long-term dataset of both vessel- and aerial surveys, as well as tracking data of frigatebirds. By developing species distribution models (SDMs, we identified key marine areas for tropical predators in relation to contemporaneous oceanographic features to investigate multi-species spatial overlap areas and identify predator hotspots in the Mozambique Channel. SDMs reasonably matched observed patterns and both static (e.g. bathymetry and dynamic (e.g. Chlorophyll a concentration and sea surface temperature factors were important explaining predator distribution patterns. We found that the distribution of frigatebirds included the distributions of the associated species. The central part of the channel appeared to be the best habitat for the four groups of species considered in this study (frigatebirds, brown terns, boobies and sub-surface predators.

  14. Impacts of aerosol particles on the microphysical and radiative properties of stratocumulus clouds over the southeast Pacific Ocean

    Directory of Open Access Journals (Sweden)

    C. H. Twohy

    2013-03-01

    Full Text Available The southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles on the stratocumulus deck was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, droplets were collected and evaporated using a counterflow virtual impactor (CVI, and the non-volatile residual particles were analyzed. Many flights focused on the gradient in cloud properties on an E-W track along 20° S from near the Chilean coast to remote areas offshore. Mean statistics, including their significance, from eight flights and many individual legs were compiled. Consistent with a continental source of cloud condensation nuclei, below-cloud accumulation-mode aerosol and droplet number concentration generally decreased from near shore to offshore. Single particle analysis was used to reveal types and sources of the enhanced particle number that influence droplet concentration. While a variety of particle types were found throughout the region, the dominant particles near shore were partially neutralized sulfates. Modeling and chemical analysis indicated that the predominant source of these particles in the marine boundary layer along 20° S was anthropogenic pollution from central Chilean sources, with copper smelters a relatively small contribution. Cloud droplets were smaller in regions of enhanced particles near shore. However, physically thinner clouds, and not just higher droplet number concentrations from pollution, both contributed to the smaller droplets. Satellite measurements were used to show that cloud albedo was highest 500–1000 km offshore, and actually slightly lower closer to shore due to the generally thinner clouds and lower

  15. Skill of ship-following large-eddy simulations in reproducing MAGIC observations across the northeast Pacific stratocumulus to cumulus transition region

    Science.gov (United States)

    McGibbon, J.; Bretherton, C. S.

    2017-06-01

    During the Marine ARM GPCI Investigation of Clouds (MAGIC) in October 2011 to September 2012, a container ship making periodic cruises between Los Angeles, CA, and Honolulu, HI, was instrumented with surface meteorological, aerosol and radiation instruments, a cloud radar and ceilometer, and radiosondes. Here large-eddy simulation (LES) is performed in a ship-following frame of reference for 13 four day transects from the MAGIC field campaign. The goal is to assess if LES can skillfully simulate the broad range of observed cloud characteristics and boundary layer structure across the subtropical stratocumulus to cumulus transition region sampled during different seasons and meteorological conditions. Results from Leg 15A, which sampled a particularly well-defined stratocumulus to cumulus transition, demonstrate the approach. The LES reproduces the observed timing of decoupling and transition from stratocumulus to cumulus and matches the observed evolution of boundary layer structure, cloud fraction, liquid water path, and precipitation statistics remarkably well. Considering the simulations of all 13 cruises, the LES skillfully simulates the mean diurnal variation of key measured quantities, including liquid water path (LWP), cloud fraction, measures of decoupling, and cloud radar-derived precipitation. The daily mean quantities are well represented, and daily mean LWP and cloud fraction show the expected correlation with estimated inversion strength. There is a -0.6 K low bias in LES near-surface air temperature that results in a high bias of 5.6 W m-2 in sensible heat flux (SHF). Overall, these results build confidence in the ability of LES to represent the northeast Pacific stratocumulus to trade cumulus transition region.Plain Language SummaryDuring the Marine ARM GPCI Investigation of Clouds (MAGIC) field campaign in October 2011 to September 2012, a cargo container ship making regular cruises between Los Angeles, CA, and Honolulu, HI, was fitted with tools to

  16. Estimates for the Probabilities of Surface-to-Air Cloud-Free Lines-of-Sight and Low Cloud Statistics from Ship Observations. Part 1. Fifteen Marine Locations.

    Science.gov (United States)

    1980-11-24

    time before and after) or cumulus fractus of bad weath’er, or both ( pannus ), usually below altostratus or nimbostratus. 8 = Cumulus and stratocumulus...vibrous upper part by cumulus, stratocumulus, stratus or pannus . + . from Surface Marine Observations Tape Deck TDF-11 *Fog All clouds in the 0-50...Fractus of bad weather, cr V both ( pannus ), usually below Alto- stratus or N~imbostratus. The term "bad weather* denotes the conditions which coenerally

  17. Development and impact of hooks of high droplet concentration on remote southeast Pacific stratocumulus

    Directory of Open Access Journals (Sweden)

    R. C. George

    2013-07-01

    Full Text Available Over the southeastern Pacific (SEP, droplet concentration (Nd in the typically unpolluted marine stratocumulus west of 80° W (> 1000 km offshore is periodically strongly enhanced in zonally elongated "hook"-shaped features that increase albedo. Here, we examine three hook events using the chemistry version of the Weather Research and Forecasting model (WRF-Chem with 14 km horizontal resolution, satellite data, and aircraft data from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx. A particularly strong hook yields insights into the development, decay, and radiative impact of these features. Hook development occurs with Nd increasing to polluted levels over the remote ocean primarily due to entrainment of cloud condensation nuclei (CCN from the lower free troposphere (FT. The feature advects northwestward until the FT CCN source is depleted, after which Nd decreases over a few days due to precipitation and dilution. The model suggests that the FT CCN source supplying the hook consists of high concentrations of small accumulation-mode aerosols that contribute a relatively small amount of aerosol mass to the MBL, in agreement with near-coast VOCALS measurements of polluted layers in the FT. The aerosol particles in this hook originate mainly from a pulse of offshore flow that transports Santiago-region (33–35° S emissions to the remote marine FT. To provide pollution CCN that can sustain hooks, the FT transport of pollution plumes to the remote ocean requires strong, deep offshore flow. Such flow is favored by a trough approaching the South American coast and a southeastward shift of the climatological subtropical high-pressure system. The model simulations show precipitation suppression in the hook and a corresponding increase in liquid water path (LWP compared with a simulation without anthropogenic sources. LWP also increases as the hook evolves over time due to increasing stability and decreasing subsidence. WRF

  18. New pathway of stratocumulus to cumulus transition via aerosol-cloud-precipitation interaction

    Science.gov (United States)

    Yamaguchi, T.; Feingold, G.; Kazil, J.

    2017-12-01

    The stratocumulus to cumulus transition (SCT) is typically considered to be a slow, multi-day process, caused primarily by dry air entrainment associated with overshooting cumulus rising under stratocumulus, with minor influence of precipitation. In this presentation, we show rapid SCT induced by a strong precipitation-induced modulation with Lagrangian SCT large eddy simulations. A large eddy model is coupled with a two-moment bulk microphysics scheme that predicts aerosol and droplet number concentrations. Moderate aerosol concentrations (100-250 cm-3) produce little to no drizzle from the stratocumulus deck. Large amounts of rain eventually form and wash out stratocumulus and much of the aerosol, and a cumulus state appears for approximately 10 hours. Initiation of strong rain formation is identified in penetrative cumulus clouds which are much deeper than stratocumulus, and they are able to condense large amounts of water. We show that prediction of cloud droplet number is necessary for this fast SCT since it is a result of a positive feedback of collision-coalescence induced aerosol depletion enhancing drizzle formation. Simulations with fixed droplet concentrations that bracket the time varying aerosol/drop concentrations are therefore not representative of the role of drizzle in the SCT.

  19. Recreational Fish-Finders--An Inexpensive Alternative to Scientific Echo-Sounders for Unravelling the Links between Marine Top Predators and Their Prey.

    Directory of Open Access Journals (Sweden)

    Alistair M McInnes

    Full Text Available Studies investigating how mobile marine predators respond to their prey are limited due to the challenging nature of the environment. While marine top predators are increasingly easy to study thanks to developments in bio-logging technology, typically there is scant information on the distribution and abundance of their prey, largely due to the specialised nature of acquiring this information. We explore the potential of using single-beam recreational fish-finders (RFF to quantify relative forage fish abundance and draw inferences of the prey distribution at a fine spatial scale. We compared fish school characteristics as inferred from the RFF with that of a calibrated scientific split-beam echo-sounder (SES by simultaneously operating both systems from the same vessel in Algoa Bay, South Africa. Customized open-source software was developed to extract fish school information from the echo returns of the RFF. For schools insonified by both systems, there was close correspondence between estimates of mean school depth (R2 = 0.98 and school area (R2 = 0.70. Estimates of relative school density (mean volume backscattering strength; Sv measured by the RFF were negatively biased through saturation of this system given its smaller dynamic range. A correction factor applied to the RFF-derived density estimates improved the comparability between the two systems. Relative abundance estimates using all schools from both systems were congruent at scales from 0.5 km to 18 km with a strong positive linear trend in model fit estimates with increasing scale. Although absolute estimates of fish abundance cannot be derived from these systems, they are effective at describing prey school characteristics and have good potential for mapping forage fish distribution and relative abundance. Using such relatively inexpensive systems could greatly enhance our understanding of predator-prey interactions.

  20. Recreational Fish-Finders—An Inexpensive Alternative to Scientific Echo-Sounders for Unravelling the Links between Marine Top Predators and Their Prey

    Science.gov (United States)

    McInnes, Alistair M.; Khoosal, Arjun; Murrell, Ben; Merkle, Dagmar; Lacerda, Miguel; Nyengera, Reason; Coetzee, Janet C.; Edwards, Loyd C.; Ryan, Peter G.; Rademan, Johan; van der Westhuizen, Jan J; Pichegru, Lorien

    2015-01-01

    Studies investigating how mobile marine predators respond to their prey are limited due to the challenging nature of the environment. While marine top predators are increasingly easy to study thanks to developments in bio-logging technology, typically there is scant information on the distribution and abundance of their prey, largely due to the specialised nature of acquiring this information. We explore the potential of using single-beam recreational fish-finders (RFF) to quantify relative forage fish abundance and draw inferences of the prey distribution at a fine spatial scale. We compared fish school characteristics as inferred from the RFF with that of a calibrated scientific split-beam echo-sounder (SES) by simultaneously operating both systems from the same vessel in Algoa Bay, South Africa. Customized open-source software was developed to extract fish school information from the echo returns of the RFF. For schools insonified by both systems, there was close correspondence between estimates of mean school depth (R2 = 0.98) and school area (R2 = 0.70). Estimates of relative school density (mean volume backscattering strength; Sv) measured by the RFF were negatively biased through saturation of this system given its smaller dynamic range. A correction factor applied to the RFF-derived density estimates improved the comparability between the two systems. Relative abundance estimates using all schools from both systems were congruent at scales from 0.5 km to 18 km with a strong positive linear trend in model fit estimates with increasing scale. Although absolute estimates of fish abundance cannot be derived from these systems, they are effective at describing prey school characteristics and have good potential for mapping forage fish distribution and relative abundance. Using such relatively inexpensive systems could greatly enhance our understanding of predator-prey interactions. PMID:26600300

  1. Clustering, randomness, and regularity in cloud fields. 4: Stratocumulus cloud fields

    Science.gov (United States)

    Lee, J.; Chou, J.; Weger, R. C.; Welch, R. M.

    1994-01-01

    To complete the analysis of the spatial distribution of boundary layer cloudiness, the present study focuses on nine stratocumulus Landsat scenes. The results indicate many similarities between stratocumulus and cumulus spatial distributions. Most notably, at full spatial resolution all scenes exhibit a decidedly clustered distribution. The strength of the clustering signal decreases with increasing cloud size; the clusters themselves consist of a few clouds (less than 10), occupy a small percentage of the cloud field area (less than 5%), contain between 20% and 60% of the cloud field population, and are randomly located within the scene. In contrast, stratocumulus in almost every respect are more strongly clustered than are cumulus cloud fields. For instance, stratocumulus clusters contain more clouds per cluster, occupy a larger percentage of the total area, and have a larger percentage of clouds participating in clusters than the corresponding cumulus examples. To investigate clustering at intermediate spatial scales, the local dimensionality statistic is introduced. Results obtained from this statistic provide the first direct evidence for regularity among large (more than 900 m in diameter) clouds in stratocumulus and cumulus cloud fields, in support of the inhibition hypothesis of Ramirez and Bras (1990). Also, the size compensated point-to-cloud cumulative distribution function statistic is found to be necessary to obtain a consistent description of stratocumulus cloud distributions. A hypothesis regarding the underlying physical mechanisms responsible for cloud clustering is presented. It is suggested that cloud clusters often arise from 4 to 10 triggering events localized within regions less than 2 km in diameter and randomly distributed within the cloud field. As the size of the cloud surpasses the scale of the triggering region, the clustering signal weakens and the larger cloud locations become more random.

  2. Clustering, randomness, and regularity in cloud fields. 4. Stratocumulus cloud fields

    Science.gov (United States)

    Lee, J.; Chou, J.; Weger, R. C.; Welch, R. M.

    1994-07-01

    To complete the analysis of the spatial distribution of boundary layer cloudiness, the present study focuses on nine stratocumulus Landsat scenes. The results indicate many similarities between stratocumulus and cumulus spatial distributions. Most notably, at full spatial resolution all scenes exhibit a decidedly clustered distribution. The strength of the clustering signal decreases with increasing cloud size; the clusters themselves consist of a few clouds (less than 10), occupy a small percentage of the cloud field area (less than 5%), contain between 20% and 60% of the cloud field population, and are randomly located within the scene. In contrast, stratocumulus in almost every respect are more strongly clustered than are cumulus cloud fields. For instance, stratocumulus clusters contain more clouds per cluster, occupy a larger percentage of the total area, and have a larger percentage of clouds participating in clusters than the corresponding cumulus examples. To investigate clustering at intermediate spatial scales, the local dimensionality statistic is introduced. Results obtained from this statistic provide the first direct evidence for regularity among large (>900 m in diameter) clouds in stratocumulus and cumulus cloud fields, in support of the inhibition hypothesis of Ramirez and Bras (1990). Also, the size compensated point-to-cloud cumulative distribution function statistic is found to be necessary to obtain a consistent description of stratocumulus cloud distributions. A hypothesis regarding the underlying physical mechanisms responsible for cloud clustering is presented. It is suggested that cloud clusters often arise from 4 to 10 triggering events localized within regions less than 2 km in diameter and randomly distributed within the cloud field. As the size of the cloud surpasses the scale of the triggering region, the clustering signal weakens and the larger cloud locations become more random.

  3. Ekspedeerimisfirmade TOP

    Index Scriptorium Estoniae

    2008-01-01

    Ekspedeerimisfirmade TOP 57. Vt. samas: Tanel Raig. Majandus kukutab ekspedeerimisturgu. Diagramm: Väliskaubanduse statistika; Katrin Raie. Ekspedeerijad hakkavad rohkem koostööle rõhuma. Kommenteerib Jaan Lepp; Müügitulu TOP 10; Müügitulu kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Eestis registreeritud Vene hiiglane; Ekspedeerimisturu kasumiliider kaotas 20 miljonit; Küsimustele vastab OÜ Contimer juht Dmitri Redkin

  4. Satellite tagging, remote sensing, and autonomous vehicles reveal interactions between physiology and environment in a North Pacific top marine predator species

    Science.gov (United States)

    Pelland, N.; Sterling, J.; Springer, A.; Iverson, S.; Johnson, D.; Lea, M. A.; Bond, N. A.; Ream, R.; Lee, C.; Eriksen, C.

    2016-02-01

    Behavioral responses by top marine predators to oceanographic features such as eddies, river plumes, storms, and coastal topography suggest that biophysical interactions in these zones affect predators' prey, foraging behaviors, and potentially fitness. However, examining these pathways is challenged by the obstacles inherent in obtaining simultaneous observations of surface and subsurface environmental fields and predator behavior. This work describes recent publications and ongoing studies of northern fur seal (NFS) foraging ecology during their 8-month migration. Satellite-tracked movement and dive behavior in the North Pacific ocean was compared to remotely sensed data, atmospheric reanalysis, autonomous in situ ocean sampling, and animal borne temperature and salinity data. Integration of these data demonstrates how reproductive fitness, physiology, and environment shape NFS migratory patterns. Seal mass correlates with dive ability and thus larger males exploit prey aggregating at the base of the winter mixed-layer depth in the Bering Sea and interior northern North Pacific Ocean. Smaller adult females migrate to the Gulf of Alaska and California Current ecosystems - where surface wind speeds decline, mixed-layer depths shoal, and coastal production is fueled by upwelling, coastal capes, and eddies - and less commonly to the Transitional Zone Chlorophyll Front, where fronts and eddies may concentrate prey. Surface wind speed and direction influence movement behavior of all age and size classes, though to a greater degree in the smaller pups and adult females than adult males. For naïve and physiologically less-capable pups, the timing and strength of autumn winds during migratory dispersal may play a role in shaping migratory routes and the environmental conditions faced by pups along these routes. In combination with other factors such as pup condition, this may play a role in interannual variations in overwinter survivorship.

  5. A Mixed-Layer Model perspective on stratocumulus steady-states in a perturbed climate

    NARCIS (Netherlands)

    Dal Gesso, S.; Siebesma, A.P.; de Roode, S.R.; van Wessem, J.M.

    2013-01-01

    Equilibrium states of stratocumulus are evaluated for a range of free tropospheric conditions in a Mixed-Layer Model framework using a number of different entrainment formulations. The equilibrium states show that a reduced lower tropospheric stability (LTS) and a dryer free troposphere support a

  6. Atmospheric System Research Marine Low Clouds Workshop Report, January 27-29,2016

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Wang, J. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Wood, R. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2016-06-01

    that combine radar and lidar measurements are becoming available, and these could be used to test process models, quantify precipitation responses to aerosol, and constrain climate models. Models and observations can be used to constrain how clouds respond dynamically to changing precipitation. New measurements of turbulence from ground-based remote sensing could be used to attempt to relate entrainment to the vertical and horizontal structure of turbulence in the boundary layer. Cloud-top entrainment plays a major role in modulating how low clouds respond to both aerosols and to greenhouse gases, so investment in promising new observational estimates would be beneficial. Precipitation formation and radiative cooling both help marine low clouds to organize on the mesoscale. More work is needed to develop metrics to characterize mesoscale organization, to elucidate mechanisms that determine the type and spatial scale of mesoscale cellular convection, and to understand the role of mesoscale structures in the stratocumulus-to-cumulus transition.

  7. CCN Properties of Organic Aerosol Collected Below and within Marine Stratocumulus Clouds near Monterey, California

    Directory of Open Access Journals (Sweden)

    Akua Asa-Awuku

    2015-10-01

    Full Text Available The composition of aerosol from cloud droplets differs from that below cloud. Its implications for the Cloud Condensation Nuclei (CCN activity are the focus of this study. Water-soluble organic matter from below cloud, and cloud droplet residuals off the coast of Monterey, California were collected; offline chemical composition, CCN activity and surface tension measurements coupled with Köhler Theory Analysis are used to infer the molar volume and surfactant characteristics of organics in both samples. Based on the surface tension depression of the samples, it is unlikely that the aerosol contains strong surfactants. The activation kinetics for all samples examined are consistent with rapid (NH42SO4 calibration aerosol. This is consistent with our current understanding of droplet kinetics for ambient CCN. However, the carbonaceous material in cloud drop residuals is far more hygroscopic than in sub-cloud aerosol, suggestive of the impact of cloud chemistry on the hygroscopic properties of organic matter.

  8. The Top Three Valor Awards and the United States Marine Corps: A Study from World War I to Present Day Iraq and Afghanistan

    Science.gov (United States)

    2014-06-13

    the Medal of Honor.85 “The process by which the MOH is awarded has become flawed, and the DOD must strive to bring an end to an era of overprotection ...later in the literature review. 84Ibid., 37. 85Wes J. Deaver, “The Medal of Honor, An Era of Overprotection ,” Marine Corps Gazette 94, no. 9

  9. Kinnisvarafirmade TOP 90

    Index Scriptorium Estoniae

    2002-01-01

    TOP 90. Kinnisvara valdkondade TOP 5. Käibe TOP 30. Käibe kasvu TOP 30. Rentaabluse TOP 30. Kasumi TOP 30. Kasumi kasvu TOP 30. Varade tootlikkuse TOP 30. Kinnisvarafirmade üldandmed. Kinnisvarafirmade finantsandmed

  10. Marine cloud brightening: regional applications.

    Science.gov (United States)

    Latham, John; Gadian, Alan; Fournier, Jim; Parkes, Ben; Wadhams, Peter; Chen, Jack

    2014-12-28

    The general principle behind the marine cloud brightening (MCB) climate engineering technique is that seeding marine stratocumulus clouds with substantial concentrations of roughly monodisperse sub-micrometre-sized seawater particles might significantly enhance cloud albedo and longevity, thereby producing a cooling effect. This paper is concerned with preliminary studies of the possible beneficial application of MCB to three regional issues: (1) recovery of polar ice loss, (2) weakening of developing hurricanes and (3) elimination or reduction of coral bleaching. The primary focus is on Item 1. We focus discussion herein on advantages associated with engaging in limited-area seeding, regional effects rather than global; and the levels of seeding that may be required to address changing current and near-term conditions in the Arctic. We also mention the possibility that MCB might be capable of producing a localized cooling to help stabilize the West Antarctic Ice Sheet.

  11. Analytic Closed-Form Solution of a Mixed Layer Model for Stratocumulus Clouds

    Science.gov (United States)

    Akyurek, Bengu Ozge

    Stratocumulus clouds play an important role in climate cooling and are hard to predict using global climate and weather forecast models. Thus, previous studies in the literature use observations and numerical simulation tools, such as large-eddy simulation (LES), to solve the governing equations for the evolution of stratocumulus clouds. In contrast to the previous works, this work provides an analytic closed-form solution to the cloud thickness evolution of stratocumulus clouds in a mixed-layer model framework. With a focus on application over coastal lands, the diurnal cycle of cloud thickness and whether or not clouds dissipate are of particular interest. An analytic solution enables the sensitivity analysis of implicitly interdependent variables and extrema analysis of cloud variables that are hard to achieve using numerical solutions. In this work, the sensitivity of inversion height, cloud-base height, and cloud thickness with respect to initial and boundary conditions, such as Bowen ratio, subsidence, surface temperature, and initial inversion height, are studied. A critical initial cloud thickness value that can be dissipated pre- and post-sunrise is provided. Furthermore, an extrema analysis is provided to obtain the minima and maxima of the inversion height and cloud thickness within 24 h. The proposed solution is validated against LES results under the same initial and boundary conditions. Then, the proposed analytic framework is extended to incorporate multiple vertical columns that are coupled by advection through wind flow. This enables a bridge between the micro-scale and the mesoscale relations. The effect of advection on cloud evolution is studied and a sensitivity analysis is provided.

  12. Kinnisvarafirmade TOP 90

    Index Scriptorium Estoniae

    2003-01-01

    Kinnisvarafirmade TOP 90. Rentaabluse TOP 30. Käibe TOP 30. Käibe kasvu TOP 30. Kasumi TOP 30. Kasumi kasvu TOP 30. Varade tootlikkuse TOP 30. Kinnisvarafirmade üldandmed. Kinnisvarafirmade finantsandmed

  13. Teedeehitusfirmade TOP 24

    Index Scriptorium Estoniae

    2006-01-01

    Teedeehitusfirmade TOP. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi Kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Teedeehitusfirmade üld- ja finantsandmed

  14. Koolitusfirmade TOP 50

    Index Scriptorium Estoniae

    2006-01-01

    Koolitusfirmade TOP. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Majandustegevuse kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Koolitusfirmade üld- ja finantsandmed

  15. Telekommunikatsiooni TOP aastal 2003

    Index Scriptorium Estoniae

    2004-01-01

    Telekommunikatsiooni TOP aastal 2003. Käibe TOP 10. Käibe kasvu TOP 10. Rentaabluse TOP 10. Kasumi TOP 10. Kasumi kasvu TOP 10. Omakapitali tootlikkuse TOP 10. Telekommunikatsioonifirmade üldandmed. Telekommunikatsioonifirmade finantsandmed

  16. Põllumajandustootjate TOP 50

    Index Scriptorium Estoniae

    2006-01-01

    Põllumajandustootjate TOP. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Majandustegevuse kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Põllumajandustootjate üld- ja finantsandmed

  17. Ehitusmaterjalitootjate TOP 95

    Index Scriptorium Estoniae

    2006-01-01

    Ehitusmaterjalitootjate TOP. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Ehitusmaterjalitootjate üld- ja finantsandmed

  18. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer: An ARM Mobile Facility Deployment

    Science.gov (United States)

    Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew; hide

    2015-01-01

    Capsule: A 21-month deployment to Graciosa Island in the northeastern Atlantic Ocean is providing an unprecedented record of the clouds, aerosols and meteorology in a poorly-sampled remote marine environment The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21 month (April 2009- December 2010) comprehensive dataset documenting clouds, aerosols and precipitation using the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1- 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging. The data from at Graciosa are being compared with short-range forecasts made a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a

  19. A mixed-layer model study of the stratocumulus response to changes in large-scale conditions

    NARCIS (Netherlands)

    De Roode, S.R.; Siebesma, A.P.; Dal Gesso, S.; Jonker, H.J.J.; Schalkwijk, J.; Sival, J.

    2014-01-01

    A mixed-layer model is used to study the response of stratocumulus equilibrium state solutions to perturbations of cloud controlling factors which include the sea surface temperature, the specific humidity and temperature in the free troposphere, as well as the large-scale divergence and horizontal

  20. Top Earners

    DEFF Research Database (Denmark)

    Badel, Alejandro; Daly, Moira; Huggett, Mark

    of the earnings distribution becomes thicker with age, and (3) the growth rate of earnings over the working lifetime is larger for groups with higher lifetime earnings. Models of top earners should account for these qualitative patterns and, importantly, for how they quantitatively differ across countries....

  1. Spatial variation in foraging behaviour of a marine top predator (Phoca vitulina determined by a large-scale satellite tagging program.

    Directory of Open Access Journals (Sweden)

    Ruth J Sharples

    Full Text Available The harbour seal (Phoca vitulina is a widespread marine predator in Northern Hemisphere waters. British populations have been subject to rapid declines in recent years. Food supply or inter-specific competition may be implicated but basic ecological data are lacking and there are few studies of harbour seal foraging distribution and habits. In this study, satellite tagging conducted at the major seal haul outs around the British Isles showed both that seal movements were highly variable among individuals and that foraging strategy appears to be specialized within particular regions. We investigated whether these apparent differences could be explained by individual level factors: by modelling measures of trip duration and distance travelled as a function of size, sex and body condition. However, these were not found to be good predictors of foraging trip duration or distance, which instead was best predicted by tagging region, time of year and inter-trip duration. Therefore, we propose that local habitat conditions and the constraints they impose are the major determinants of foraging movements. Specifically the distance to profitable feeding grounds from suitable haul-out locations may dictate foraging strategy and behaviour. Accounting for proximity to productive foraging resources is likely to be an important component of understanding population processes. Despite more extensive offshore movements than expected, there was also marked fidelity to the local haul-out region with limited connectivity between study regions. These empirical observations of regional exchange at short time scales demonstrates the value of large scale electronic tagging programs for robust characterization of at-sea foraging behaviour at a wide spatial scale.

  2. Clouds, Aerosols, and Precipitation in the Marine Boundary Layer: An Arm Mobile Facility Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Rémillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, J. Christine; Mann, Julian A. L.; O’Connor, Ewan J.; Hogan, Robin J.; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palikonda, Rabindra; Albrecht, Bruce; Luke, Ed; Hannay, Cecile; Lin, Yanluan

    2015-03-01

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) 38 deployment at Graciosa Island in the Azores generated a 21 month (April 2009-December 2010) 39 comprehensive dataset documenting clouds, aerosols and precipitation using the Atmospheric 40 Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is 41 to gain improved understanding of the interactions of clouds, aerosols and precipitation in the 42 marine boundary layer. 43 Graciosa Island straddles the boundary between the subtropics and midlatitudes in the 44 Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and 45 cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus 46 occurring regularly. Approximately half of all clouds contained precipitation detectable as radar 47 echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-48 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide 49 range of aerosol conditions was sampled during the deployment consistent with the diversity of 50 sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way 51 interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation 52 and cloud radiative properties while being controlled in part by precipitation scavenging. 53 The data from at Graciosa are being compared with short-range forecasts made a variety 54 of models. A pilot analysis with two climate and two weather forecast models shows that they 55 reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, 56 but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to 57 be a long-term ARM site that became operational in October 2013.

  3. Autotranspordifirmade TOP 100

    Index Scriptorium Estoniae

    2006-01-01

    Ilmunud ka: Delovõje Vedomosti : Transport i Logistika 29. nov. lk. 10-11. Autofirmade TOP 100. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Majandustegevuse kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Autotranspordifirmade üld- ja finantsandmed. Delovõje Vedomosti : Transport i Logistika sisaldab tabelit Autofirmade TOP 100

  4. Effects of stratocumulus, cumulus, and cirrus clouds on the UV-B diffuse to global ratio: Experimental and modeling results

    International Nuclear Information System (INIS)

    López, María Laura; Palancar, Gustavo G.; Toselli, Beatriz M.

    2012-01-01

    Broadband measurements of global and diffuse UV-B irradiance (280-315 nm) together with modeled and measured diffuse to global ratios (DGR) have been used to characterize the influence of different types of clouds on irradiance at the surface. Measurements were carried out during 2000-2001 in Córdoba City, Argentina. The Tropospheric Ultraviolet Visible (TUV) model was used to analyze the behavior of the modeled DGRs for different cloud optical depths and at different altitudes and solar zenith angles (SZA). Different cloud altitudes were also tested, although only the results for a cloud placed at 1.5-2.5 km of altitude are shown. A total of 16 day with stratocumulus, 12 with cumulus, and 16 with cirrus have been studied and compared among them and also against 21 clear sky days. Different behaviors were clearly detected and also differentiated through the analysis of the averages and the standard deviations of the DGRs: 1.02±0.06 for stratocumulus, 0.74±0.18 for cumulus, 0.63±0.12 for cirrus, and 0.60±0.13 for the clear sky days, respectively. Stratocumulus clouds showed a low variability in the DGR values, which were concentrated close to one at all SZAs. DGR values for cumulus clouds presented a large variability at all SZAs, mostly associated with the different optical depths. Finally, the closeness between the DGR values for cirrus clouds and the DGR values for clear days showed that these clouds generally do not strongly affect the UV-B irradiance at the surface at any SZA. In the opposite side, stratocumulus clouds were identified as those with the largest effects, at all SZAs, on the UV-B irradiance at the surface.

  5. Autotranspordi TOP aastal 2007

    Index Scriptorium Estoniae

    2008-01-01

    TOP 50. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Marika Roomere. Täisteenuse pakkumine kergitas tulemusi; Jupiter Plus otsib järjest uusi kasvuvõimalusi; EST-Trans Kaubaveod teenib kasumit toiduvedamisega

  6. Koolitusfirmade TOP aastal 2007

    Index Scriptorium Estoniae

    2008-01-01

    Koolitusfirmade TOP. Vt. samas: Käibe TOP 10; Käibekasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Signe Sillasoo. Invicta tahab lähiaastail laieneda Eestis ja mujalgi; Ketlin Priilinn. Addenda kasutas ära majanduse soodsa seisu. Kommenteerib Heli Sõmer. Juhtide hoiakute muutmisega tõus esikolmikusse

  7. Audiitorfirmade TOP aastal 2007

    Index Scriptorium Estoniae

    2008-01-01

    Audiitorfirmade TOP 51. Vt. samas: Urve Vilk. Audiitoriteni pole majanduslangus jõudnud; Intervjuu I.S. Audiitorteenuste OÜ omaniku Irina Somovaga; Käibe TOP 10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10

  8. Koolitusfirmade TOP aastal 2006

    Index Scriptorium Estoniae

    2007-01-01

    Koolitusfirmade TOP. Vt. samas: Käibe TOP10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Varade tootlikkuse TOP 10; Pille Rõivas. Võtmetegur meeskond; Vain & Partnerid: uudsus peitub sisus; Kristo Kiviorg. Teel Baltimaade koolitajate tippu

  9. Top reconstruction and boosted top experimental overview

    CERN Document Server

    Skinnari, Louise

    2015-01-01

    An overview of techniques used to reconstruct resolved and boosted top quarks is presented. Techniques for resolved top quark reconstruction include kinematic likelihood fitters and pseudo- top reconstruction. Many tools and methods are available for the reconstruction of boosted top quarks, such as jet grooming techniques, jet substructure variables, and dedicated top taggers. Different techniques as used by ATLAS and CMS analyses are described and the performance of different variables and top taggers are shown.

  10. Modelling microphysical and meteorological controls on precipitation and cloud cellular structures in Southeast Pacific stratocumulus

    Directory of Open Access Journals (Sweden)

    H. Wang

    2010-07-01

    Full Text Available Microphysical and meteorological controls on the formation of open and closed cellular structures in the Southeast Pacific are explored using model simulations based on aircraft observations during the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx. The effectiveness of factors such as boundary-layer moisture and temperature perturbations, surface heat and moisture fluxes, large-scale vertical motion and solar heating in promoting drizzle and open cell formation for prescribed aerosol number concentrations is explored. For the case considered, drizzle and subsequent open cell formation over a broad region are more sensitive to the observed boundary-layer moisture and temperature perturbations (+0.9 g kg−1; −1 K than to a five-fold decrease in aerosol number concentration (150 vs. 30 mg−1. When embedding the perturbations in closed cells, local drizzle and pockets of open cell (POC formation respond faster to the aerosol reduction than to the moisture increase, but the latter generates stronger and more persistent drizzle. A local negative perturbation in temperature drives a mesoscale circulation that prevents local drizzle formation but promotes it in a remote area where lower-level horizontal transport of moisture is blocked and converges to enhance liquid water path. This represents a potential mechanism for POC formation in the Southeast Pacific stratocumulus region whereby the circulation is triggered by strong precipitation in adjacent broad regions of open cells. A simulation that attempts to mimic the influence of a coastally induced upsidence wave results in an increase in cloud water but this alone is insufficient to initiate drizzle. An increase of surface sensible heat flux is also effective in triggering local drizzle and POC formation.

    Both open and closed cells simulated with observed initial conditions exhibit distinct diurnal variations in cloud properties. A

  11. Evaluation of Forecasted Southeast Pacific Stratocumulus in the NCAR, GFDL and ECMWF Models

    Energy Technology Data Exchange (ETDEWEB)

    Hannay, C; Williamson, D L; Hack, J J; Kiehl, J T; Olson, J G; Klein, S A; Bretherton, C S; K?hler, M

    2008-01-24

    We examine forecasts of Southeast Pacific stratocumulus at 20S and 85W during the East Pacific Investigation of Climate (EPIC) cruise of October 2001 with the ECMWF model, the Atmospheric Model (AM) from GFDL, the Community Atmosphere Model (CAM) from NCAR, and the CAM with a revised atmospheric boundary layer formulation from the University of Washington (CAM-UW). The forecasts are initialized from ECMWF analyses and each model is run for 3 days to determine the differences with the EPIC field data. Observations during the EPIC cruise show a stable and well-mixed boundary layer under a sharp inversion. The inversion height and the cloud layer have a strong and regular diurnal cycle. A key problem common to the four models is that the forecasted planetary boundary layer (PBL) height is too low when compared to EPIC observations. All the models produce a strong diurnal cycle in the Liquid Water Path (LWP) but there are large differences in the amplitude and the phase compared to the EPIC observations. This, in turn, affects the radiative fluxes at the surface. There is a large spread in the surface energy budget terms amongst the models and large discrepancies with observational estimates. Single Column Model (SCM) experiments with the CAM show that the vertical pressure velocity has a large impact on the PBL height and LWP. Both the amplitude of the vertical pressure velocity field and its vertical structure play a significant role in the collapse or the maintenance of the PBL.

  12. Arvutifirmade TOP 101 aastal 2004

    Index Scriptorium Estoniae

    2005-01-01

    Arvutifirmade TOP 101; Käibe TOP 20; Käibe kasvu TOP 15; Kasumi TOP 15; Rentaabluse TOP 20; Kasumi kasvu TOP 15; Omakapiali tootlikkuse TOP 15; Eesti arvutifirmade finantsandmed; Arvutifirmade üldandmed

  13. Jaekaubanduse TOP 100 aastal 2001

    Index Scriptorium Estoniae

    2002-01-01

    TOP 100. Käibe TOP 30. Käibe kasvu TOP 30. Kasumi TOP 30. Kasumi kasvu TOP 30. Rentaabluse TOP 30. Varade tootlikkuse TOP 30. Jaekaubandusettevõtete finantsseadmed. Jaekaubandusettevõtete üldandmed

  14. Jaekaubandusettevõtete TOP 70

    Index Scriptorium Estoniae

    2005-01-01

    Jaekaubandusettevõtete TOP 70; Käibe TOP 25; Kasumi TOP 25; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20; Jaekaubandusettevõtete üld- ja finantsandmed

  15. Majutusasutuste TOP 40 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Majutusasutuste TOP 40 aastal 2002. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Majutusasutuste üldandmed. Majutusasutuste finantsandmed

  16. Sensitivity to deliberate sea salt seeding of marine clouds – observations and model simulations

    Directory of Open Access Journals (Sweden)

    K. Alterskjær

    2012-03-01

    Full Text Available Sea salt seeding of marine clouds to increase their albedo is a proposed technique to counteract or slow global warming. In this study, we first investigate the susceptibility of marine clouds to sea salt injections, using observational data of cloud droplet number concentration, cloud optical depth, and liquid cloud fraction from the MODIS (Moderate Resolution Imaging Spectroradiometer instruments on board the Aqua and Terra satellites. We then compare the derived susceptibility function to a corresponding estimate from the Norwegian Earth System Model (NorESM. Results compare well between simulations and observations, showing that stratocumulus regions off the west coast of the major continents along with large regions over the Pacific and the Indian Oceans are susceptible. At low and mid latitudes the signal is dominated by the cloud fraction.

    We then carry out geo-engineering experiments with a uniform increase over ocean of 10−9 kg m−2 s−1 in emissions of sea salt particles with a dry modal radius of 0.13 μm, an emission strength and areal coverage much greater than proposed in earlier studies. The increased sea salt concentrations and the resulting change in marine cloud properties lead to a globally averaged forcing of −4.8 W m−2 at the top of the atmosphere, more than cancelling the forcing associated with a doubling of CO2 concentrations. The forcing is large in areas found to be sensitive by using the susceptibility function, confirming its usefulness as an indicator of where to inject sea salt for maximum effect.

    Results also show that the effectiveness of sea salt seeding is reduced because the injected sea salt provides a large surface area for water vapor and gaseous sulphuric acid to condense on, thereby lowering the maximum supersaturation and suppressing the formation and lifetime of sulphate particles. In some areas, our simulations show an

  17. Reisifirmade TOP 40 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Reisifirmade TOP 40 aastal 2002. Reisifirmade TOP-i esikümme. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Reisifirmade üldandmed. Reisifirmade finantsandmed. Tehnilise käibe alusel arvutatud edetabelid: Reisifirmade TOP 25; Käibe TOP 40; Rentaabluse TOP 10; Käibe kasvu TOP 10

  18. Low cloud investigations for project FIRE: Island studies of cloud properties, surface radiation, and boundary layer dynamics. A simulation of the reflectivity over a stratocumulus cloud deck by the Monte Carlo method. M.S. Thesis Final Report

    Science.gov (United States)

    Ackerman, Thomas P.; Lin, Ruei-Fong

    1993-01-01

    The radiation field over a broken stratocumulus cloud deck is simulated by the Monte Carlo method. We conducted four experiments to investigate the main factor for the observed shortwave reflectively over the FIRE flight 2 leg 5, in which reflectivity decreases almost linearly from the cloud center to cloud edge while the cloud top height and the brightness temperature remain almost constant through out the clouds. From our results, the geometry effect, however, did not contribute significantly to what has been observed. We found that the variation of the volume extinction coefficient as a function of its relative position in the cloud affects the reflectivity efficiently. Additional check of the brightness temperature of each experiment also confirms this conclusion. The cloud microphysical data showed some interesting features. We found that the cloud droplet spectrum is nearly log-normal distributed when the clouds were solid. However, whether the shift of cloud droplet spectrum toward the larger end is not certain. The decrease of number density from cloud center to cloud edges seems to have more significant effects on the optical properties.

  19. Intergenerational Top Income Persistence

    DEFF Research Database (Denmark)

    Munk, Martin D.; Bonke, Jens; Hussain, M. Azhar

    2016-01-01

    In this paper, we investigate intergenerational top earnings and top income mobility in Denmark. Access to administrative registers allowed us to look at very small fractions of the population. We find that intergenerational mobility is lower in the top when including capital income in the income...... measure— for the rich top 0.1% fathers and sons the elasticity is 0.466. Compared with Sweden, however, the intergenerational top income persistence is about half the size in Denmark....

  20. Top quark property measurements in single top

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00386283; The ATLAS collaboration

    2016-01-01

    A review of the recent results on measurements of top quark properties in single top quark processes, performed at the LHC by ATLAS and CMS is presented. The measurements are in good agreement with predictions and no deviations from Standard Model expectations have been observed.

  1. Recent Findings Related to Giant Cloud Condensation Nuclei in the Marine Boundary Layer and Impacts on Clouds and Precipitation

    Science.gov (United States)

    Sorooshian, Armin; Dadashazar, Hossein; Wang, Zhen; Crosbie, Ewan; Brunke, Michael; Zeng, Xubin; Jonsson, Haflidi; Woods, Roy; Flagan, Richard; Seinfeld, John

    2017-04-01

    This presentation reports on findings from multiple airborne field campaigns off the California coast to understand the sources, nature, and impacts of giant cloud condensation nuclei (GCCN). Aside from sea spray emissions, measurements have revealed that ocean-going ships can be a source of GCCN due to wake and stack emissions off the California coast. Observed particle number concentrations behind 10 ships exceeded those in "control" areas, exhibiting number concentration enhancement ratios (ERs) for minimum threshold diameters of 2, 10, and 20 μm as high as 2.7, 5.5, and 7.5, respectively. The data provide insights into how ER is related to a variety of factors (downwind distance, altitude, ship characteristics such as gross tonnage, length, and beam). The data also provide insight into the extent to which a size distribution parameter and a cloud water chemical measurement can capture the effect of sea salt on marine stratocumulus cloud properties. The two GCCN proxy variables, near-surface particle number concentration for diameter > 5 µm and cloud water chloride concentration, are significantly correlated with each other, and both exhibit expected relationships with other parameters that typically coincide with sea salt emissions. Factors influencing the relationship between these two GCCN proxy measurements will be discussed. When comparing twelve pairs of high and low chloride cloud cases (at fixed liquid water path and cloud drop number concentration), the average drop spectra for high chloride cases exhibit enhanced drop number at diameters exceeding 20 µm, especially above 30 µm. In addition, high chloride cases coincide with enhanced mean columnar R and negative values of precipitation susceptibility. The difference in drop effective radius (re) between high and low chloride conditions decreases with height in cloud, suggesting that some GCCN-produced rain drops precipitate before reaching cloud tops. The sign of cloud responses (i.e., re, R) to

  2. Island based radar and microwave radiometer measurements of stratus cloud parameters during the Atlantic Stratocumulus Transition Experiment (ASTEX)

    Energy Technology Data Exchange (ETDEWEB)

    Frisch, A.S. [Colorado State Univ., Fort Collins, CO (United States); Fairall, C.W.; Snider, J.B. [NOAA Environmental Technology Lab., Boulder, CO (United States); Lenshow, D.H.; Mayer, S.D. [National Center for Atmospheric Research, Boulder, CO (United States)

    1996-04-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, simultaneous measurements were made with a vertically pointing cloud sensing radar and a microwave radiometer. The radar measurements are used to estimate stratus cloud drizzle and turbulence parameters. In addition, with the microwave radiometer measurements of reflectivity, we estimated the profiles of cloud liquid water and effective radius. We used radar data for computation of vertical profiles of various drizzle parameters such as droplet concentration, modal radius, and spread. A sample of these results is shown in Figure 1. In addition, in non-drizzle clouds, with the radar and radiometer we can estimate the verticle profiles of stratus cloud parameters such as liquid water concentration and effective radius. This is accomplished by assuming a droplet distribution with droplet number concentration and width constant with height.

  3. Audiitorfirmade TOP 50 aastal 2000

    Index Scriptorium Estoniae

    2001-01-01

    Audiitorfirmade käibe TOP 50, käibe kasvu TOP 25, käibe languse TOP 15, kasumi TOP 50, kasumi kasvu TOP 10, kasumi languse TOP 10, audiitorfirmade finantsnäitajad. Rentaabluse TOP 50, varade tootlikkuse TOP 50

  4. Top Production at LHCb

    CERN Multimedia

    Santana Rangel, Murilo

    2015-01-01

    Single and pair top production in the forward direction at the LHC allows for precision tests of the Standard Model. The observation of top quarks in 7 and 8 TeV data and prospects for precision measurements are shown.

  5. The Development of Coastal and Marine

    Directory of Open Access Journals (Sweden)

    Suharto Widjojo

    2004-01-01

    Full Text Available Planning and development process of oastaland marine resources tends centralized and adopted top down policy, without any active participations from coastal and marine communities. In order to reach integrated and sustainable development in coastaland marine areas, people should have both complete and up to date information, so that planning and decision making for all aspect of the environment can be done easily. People should give a high attention of surveis, mappings, as well as science and technology of coastal and marine sectors, in order to change the paradigm of development from inland to coastal and marine. Moreover, people should give high attention of potential resources of coastal and marine areas.

  6. Top Physics at Atlas

    CERN Document Server

    Romano, M; The ATLAS collaboration

    2013-01-01

    This talk is an overview of recent results on top-quark physics obtained by the ATLAS collaboration from the analysis of p-p collisions at 7 and 8 TeV at the Large Hadron Collider. Total and differential top pair cross section, single top cross section and mass measurements are presented.

  7. CDF Top Physics

    Science.gov (United States)

    Tartarelli, G. F.; CDF Collaboration

    1996-05-01

    The authors present the latest results about top physics obtained by the CDF experiment at the Fermilab Tevatron collider. The data sample used for these analysis (about 110 pb{sup{minus}1}) represents almost the entire statistics collected by CDF during four years (1992--95) of data taking. This large data size has allowed detailed studies of top production and decay properties. The results discussed here include the determination of the top quark mass, the measurement of the production cross section, the study of the kinematics of the top events and a look at top decays.

  8. Turismifirmade 2000. a. TOP 30

    Index Scriptorium Estoniae

    2001-01-01

    Turismiettevõtete üldandmed: turismiettevõtete finantsnäitajad; käibe TOP 30; käibe kasvu TOP 10; kasumi TOP 20; kasumi kasvu TOP 10; kasumi languse TOP; rentaabluse TOP 10; varade tootlikkuse TOP 10

  9. Ehitusmaterjalitootjate TOP 70 aastal 2003

    Index Scriptorium Estoniae

    2004-01-01

    Ilmunud ka: Delovõje Vedomosti : Stroitelstvo, 29. sept. 2004, lk. 2,4. Ehitusmaterjalitootjate TOP 70; Käibe TOP 10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP. Ehitusmaterjalitootjate üldandmed

  10. Remote Sensing of Cloud Top Height from SEVIRI: Analysis of Eleven Current Retrieval Algorithms

    Science.gov (United States)

    Hamann, U.; Walther, A.; Baum, B.; Bennartz, R.; Bugliaro, L.; Derrien, M.; Francis, P. N.; Heidinger, A.; Joro, S.; Kniffka, A.; hide

    2014-01-01

    The role of clouds remains the largest uncertainty in climate projections. They influence solar and thermal radiative transfer and the earth's water cycle. Therefore, there is an urgent need for accurate cloud observations to validate climate models and to monitor climate change. Passive satellite imagers measuring radiation at visible to thermal infrared (IR) wavelengths provide a wealth of information on cloud properties. Among others, the cloud top height (CTH) - a crucial parameter to estimate the thermal cloud radiative forcing - can be retrieved. In this paper we investigate the skill of ten current retrieval algorithms to estimate the CTH using observations from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) onboard Meteosat Second Generation (MSG). In the first part we compare ten SEVIRI cloud top pressure (CTP) data sets with each other. The SEVIRI algorithms catch the latitudinal variation of the CTP in a similar way. The agreement is better in the extratropics than in the tropics. In the tropics multi-layer clouds and thin cirrus layers complicate the CTP retrieval, whereas a good agreement among the algorithms is found for trade wind cumulus, marine stratocumulus and the optically thick cores of the deep convective system. In the second part of the paper the SEVIRI retrievals are compared to CTH observations from the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR) instruments. It is important to note that the different measurement techniques cause differences in the retrieved CTH data. SEVIRI measures a radiatively effective CTH, while the CTH of the active instruments is derived from the return time of the emitted radar or lidar signal. Therefore, some systematic differences are expected. On average the CTHs detected by the SEVIRI algorithms are 1.0 to 2.5 kilometers lower than CALIOP observations, and the correlation coefficients between the SEVIRI and the CALIOP data sets range between 0.77 and 0

  11. TOP LINAC design; Progetto del TOP LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Picardi, L; Ronsivalle, C; Vignati, A [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione

    1997-11-01

    The report describes a linear accelerator for protons named TOP LINAC designed for the TOP (Terapia Oncologica con Protoni, Oncological Protontherapy) project launched by the Italian National Institute of Health (Istituto Superiore di Sanita`, ISS) to explore in collaboration with the biggest Oncological Hospital in Rome (Istituto Regina Elena, IRE) the potentialities of the therapy with accelerated protons and establish guide lines for the application of this new type of radiotherapy in comparison with the more traditional electron and x-rays radiotherapy. The concept of a compact accelerator for protontherapy applications bore within the Italian Hadrontherapy Collaboration (TERA Collaboration) with the aim to diffuse the protontherapy on the National territory. The ISS program plans to use the TOP linac proton beam also for production of PET (Positron Emission Tomography) radioisotopes and radiobiology studies. Official agreements are in course between ISS and ENEA which provides its experience in the industrial and medical accelerators for the design and the construction of the TOP linac. The accelerator that will be the first 3 GHz proton linac in the world, will be composed of a 428.3 MHz 7 Me V RFQ + DTL injector followed by a 7-65 Me V section of a 3 GHz SCDTL structure and a 65 - 200 Me V variable energy SCL 3 GHz structure. In particular the SCDTL section uses a highly innovative accelerating structure patented by ENEA. In this report the clinical and physical requests are discussed and a preliminary design of the whole machine is given.

  12. Ekspedeerimisettevõtete TOP 50

    Index Scriptorium Estoniae

    2006-01-01

    Ilmunud ka: Delovõje Vedomosti : Transport i Logistika nr. 11, 29. nov. lk. 32-35. Ekspedeerimisettevõtete TOP. Vt. samas: Käibe TOP 10; Käibekasvu TOP 10; Kasumi TOP 10; Kasumikasvu TOP 10; Rentaabluse TOP 10; ROE TOP 10; Ekspedeerimisettevõtete üld- ja finantsandmed. Ajal. Delovõje Vedomosti : Transport i Logistika toodud ainult Ekspedeerimisettevõtete TOP 50

  13. Contrasting Cloud Composition Between Coupled and Decoupled Marine Boundary Layer Clouds

    Science.gov (United States)

    WANG, Z.; Mora, M.; Dadashazar, H.; MacDonald, A.; Crosbie, E.; Bates, K. H.; Coggon, M. M.; Craven, J. S.; Xian, P.; Campbell, J. R.; AzadiAghdam, M.; Woods, R. K.; Jonsson, H.; Flagan, R. C.; Seinfeld, J.; Sorooshian, A.

    2016-12-01

    Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the ocean surface. This study contrasts cloud chemical composition between coupled and decoupled marine stratocumulus clouds. Cloud water and droplet residual particle composition were measured in clouds off the California coast during three airborne experiments in July-August of separate years (E-PEACE 2011, NiCE 2013, BOAS 2015). Decoupled clouds exhibited significantly lower overall mass concentrations in both cloud water and droplet residual particles, consistent with reduced cloud droplet number concentration and sub-cloud aerosol (Dp > 100 nm) number concentration, owing to detachment from surface sources. Non-refractory sub-micrometer aerosol measurements show that coupled clouds exhibit higher sulfate mass fractions in droplet residual particles, owing to more abundant precursor emissions from the ocean and ships. Consequently, decoupled clouds exhibited higher mass fractions of organics, nitrate, and ammonium in droplet residual particles, owing to effects of long-range transport from more distant sources. Total cloud water mass concentration in coupled clouds was dominated by sodium and chloride, and their mass fractions and concentrations exceeded those in decoupled clouds. Conversely, with the exception of sea salt constituents (e.g., Cl, Na, Mg, K), cloud water mass fractions of all species examined were higher in decoupled clouds relative to coupled clouds. These results suggest that an important variable is the extent to which clouds are coupled to the surface layer when interpreting microphysical data relevant to clouds and aerosol particles.

  14. Top Quark Physics

    International Nuclear Information System (INIS)

    Larios, F.

    2006-01-01

    We give an overview of the physics of the Top quark, from the experimental discovery to the studies of its properties. We review some of the work done on the Electroweak and Flavor Changing couplings associated with the Top quark in the Standard Model and beyond. We will focus on the specific contribution of phycisits working in Mexico and Mexican physicists working abroad

  15. Top quark theory

    NARCIS (Netherlands)

    Laenen, E.

    2012-01-01

    The theoretical aspects of a number of top quark properties such as its mass and its couplings are reviewed. Essential aspects in the theoretical description of top quark production, singly, in pairs and in association, as well as its decay related to spin and angular correlations are discussed.

  16. Top physics at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.E. [Univ. of Rochester, NY (United States)

    1997-01-01

    We report on top physics results using a 100 pb{sup -1} data sample of p{bar p} collisions at {radical}s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). We have identified top signals in a variety of decay channels, and used these channels to extract a measurement of the top mass and production cross section. A subset of the data (67 pb{sup -1}) is used to determine M{sub top} = 176 {+-} 8(stat) {+-} 10(syst) and {sigma}(tt) = 7.6 {sub -2.0}{sup +2.4} pb. We present studies of the kinematics of t{bar t} events and extract the first direct measurement of V{sub tb}. Finally, we indicate prospects for future study of top physics at the Tevatron.

  17. Top Quark Mass

    CERN Document Server

    Mulders, Martijn

    2016-01-01

    Ever since the discovery of the top quark at the Tevatron collider in 1995 the measurement of its mass has been a high priority. As one of the fundamental parameters of the Standard Theory of particle physics, the precise value of the top quark mass together with other inputs provides a test for the self-consistency of the theory, and has consequences for the stability of the Higgs field that permeates the Universe. In this review I will briefly summarize the experimental techniques used at the Tevatron and the LHC experiments throughout the years to measure the top quark mass with ever improving accuracy, and highlight the recent progress in combining all measurements in a single world average combination. As experimental measurements became more precise, the question of their theoretical interpretation has become important. The difficulty of relating the measured quantity to the fundamental top mass parameter has inspired alternative measurement methods that extract the top mass in complementary ways. I wil...

  18. Top quark mass measurement

    International Nuclear Information System (INIS)

    Maki, Tuula; Helsinki Inst. of Phys.; Helsinki U. of Tech.

    2008-01-01

    The top quark is the heaviest elementary particle. Its mass is one of the fundamental parameters of the standard model of particle physics, and an important input to precision electroweak tests. This thesis describes three measurements of the top-quark mass in the dilepton decay channel. The dilepton events have two neutrinos in the final state; neutrinos are weakly interacting particles that cannot be detected with a multipurpose experiment. Therefore, the signal of dilepton events consists of a large amount of missing energy and momentum carried off by the neutrinos. The top-quark mass is reconstructed for each event by assuming an additional constraint from a top mass independent distribution. Template distributions are constructed from simulated samples of signal and background events, and parameterized to form continuous probability density functions. The final top-quark mass is derived using a likelihood fit to compare the reconstructed top mass distribution from data to the parameterized templates. One of the analyses uses a novel technique to add top mass information from the observed number of events by including a cross-section-constraint in the likelihood function. All measurements use data samples collected by the CDF II detector

  19. Top physics in WHIZARD

    Energy Technology Data Exchange (ETDEWEB)

    Reuter, Juergen; Chokoufe Nejad, Bijan [DESY, Hamburg (Germany). Theory Group; Bach, Fabian [European Commission, Eurostat, Luxembourg (Luxembourg); Hoang, Andre [Vienna Univ. (Austria). Faculty of Physics; Vienna Univ. (Austria). Erwin Schroedinger International Inst. for Mathematical Physics; Kilian, Wolfgang [Siegen Univ. (Germany); Stahlhofen, Maximilian [Mainz Univ. (Germany). PRISMA Cluster of Excellence; Teubner, Thomas [Liverpool Univ. (United Kingdom). Dept. of Mathematical Sciences; Weiss, Christian [DESY, Hamburg (Germany). Theory Group; Siegen Univ. (Germany)

    2016-03-15

    In this talk we summarize the top physics setup in the event generator WHIZARD with a main focus on lepton colliders. This includes full six-, eight- and ten-fermion processes, factorized processes and spin correlations. For lepton colliders, QCD NLO processes for top quark physics are available and discussed. A special focus is on the top-quark pair threshold, where a special implementation combines a non-relativistic effective field theory calculation augmented by a next-to-leading threshold logarithm resummation with a continuum relativistic fixed-order QCD NLO simulation.

  20. Top physics in WHIZARD

    International Nuclear Information System (INIS)

    Reuter, Juergen; Chokoufe Nejad, Bijan; Hoang, Andre; Stahlhofen, Maximilian

    2016-03-01

    In this talk we summarize the top physics setup in the event generator WHIZARD with a main focus on lepton colliders. This includes full six-, eight- and ten-fermion processes, factorized processes and spin correlations. For lepton colliders, QCD NLO processes for top quark physics are available and discussed. A special focus is on the top-quark pair threshold, where a special implementation combines a non-relativistic effective field theory calculation augmented by a next-to-leading threshold logarithm resummation with a continuum relativistic fixed-order QCD NLO simulation.

  1. Top quark discovered

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Nine months after a careful announcement of tentative evidence for the long-awaited sixth 'top' quark, physicists from the CDF and DO experiments at Fermilab's Tevatron proton-antiproton collider declared on 2 March that they had finally discovered the top quark. Last year (June 1994, page 1), the CDF experiment at the Tevatron reported a dozen candidate top events. These, said CDF, had all the characteristics expected of top, but the difficulties of extracting the tiny signal from a trillion proton-antiproton collisions made them shy of claiming a discovery. For its part, the companion DO Tevatron experiment reported a few similar events but were even more guarded about their interpretation as top quarks. Just after these hesitant announcements, performance at the Tevatron improved dramatically last summer. After the commissioning of a new linear accelerator and a magnet realignment, the machine reached a new world record proton-antiproton collision luminosity of 1.28 x 10 31 per sq cm per s, ten times that originally planned. Data began to pour in at an unprecedented rate and the data sample grew to six trillion collisions. Luminosity has subsequently climbed to 1.7 x 10 31 . The top quark is the final letter in the alphabet of Standard Model particles. According to this picture, all matter is composed of six stronglyinteracting subnuclear particles, the quarks, and six weakly interacting particles, the leptons. Both sextets are neatly arranged as three pairs in order of increasing mass. The fifth quark, the 'beauty' or 'b' quark, was also discovered at Fermilab, back in 1977. Since then physicists have been eagerly waiting for the top to turn up, but have been frustrated by its heaviness - the top is some 40 times the mass of its 'beautiful' partner. Not only is the top quark the heaviest by far, but it is the only quark which has been actively hunted. After the quarry was glimpsed last year, the net has now been

  2. Audiitorite TOP 50 aastal 2005

    Index Scriptorium Estoniae

    2006-01-01

    Audiitorite TOP. Vt. samas: Käibe TOP 10; Käibe kasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; ROE TOP 10; Ketlin Priilinn. Kasvu tagavad lojaalsed kliendid; Klient on audiitori parim müügimees; Teeli Remmelg. Kliendid vaatavad pigem kvaliteeti kui madalat hinda. Kommenteerivad Signe Keernik ja Kalle Lahe. Tabel: Audiitoriettevõtete üld- ja finantsandmed

  3. Marine ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Studies on marine ecology included marine pollution; distribution patterns of Pu and Am in the marine waters, sediments, and organisms of Bikini Atoll and the influence of physical, chemical, and biological factors on their movements through marine biogeochemical systems; transfer and dispersion of organic pollutants from an oil refinery through coastal waters; transfer of particulate pollutants, including sediments dispersed during construction of offshore power plants; and raft culture of the mangrove oysters

  4. Marine pollution

    International Nuclear Information System (INIS)

    Albaiges, J.

    1989-01-01

    This book covers the following topics: Transport of marine pollutants; Transformation of pollutants in the marine environment; Biological effects of marine pollutants; Sources and transport of oil pollutants in the Persian Gulf; Trace metals and hydrocarbons in Syrian coastal waters; and Techniques for analysis of trace pollutants

  5. Jõgevamaa ettevõtete TOP 55

    Index Scriptorium Estoniae

    2004-01-01

    Jõgevamaa ettevõtete TOP 55 aastal 2003. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Jõgevamaa firmade üld- ja finantsandmed

  6. Põlvamaa ettevõtete TOP 50

    Index Scriptorium Estoniae

    2004-01-01

    Ettevõtete TOP 50. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Põlvamaa firmade üldandmed. Põlvamaa firmade finantsandmed

  7. Viljandimaa ettevõtete TOP 50

    Index Scriptorium Estoniae

    2005-01-01

    Viljandimaa ettevõtete TOP 50; Käibe TOP 35; Kasumi TOP 35; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20; Viljandimaa ettevõtete üld- ja finantsandmed

  8. Jõgevamaa ettevõtete TOP 50

    Index Scriptorium Estoniae

    2005-01-01

    Jõgevamaa ettevõtete TOP 50; Käibe TOP 35; Kasumi TOP 35; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20; Jõgevamaa ettevõtete üld- ja finantsandmed

  9. Boosted tops at ATLAS

    CERN Document Server

    Villaplana, M; The ATLAS collaboration

    2011-01-01

    A sample of candidate events for highly boosted top quarks is selected following the standard ATLAS selection for semi-leptonic ttbar events plus a requirement that the invariant mass of the reconstructed ttbar pair is greater than 700 GeV. Event displays are presented for the most promising candidates, as well as quantitative results for observables designed to isolate a boosted top quark signal.

  10. Telekommunikatsiooni & arvutitootjate TOP

    Index Scriptorium Estoniae

    2006-01-01

    Telekommunikatsiooni TOP 30. Tabelid. Vt. samas: Indrek Kald. Elisa ka tänavu esikohal; Väike Tele2 võidab paindlikkusest; Kernel läks üle piiri. Diagrammid. Arvutifirmade TOP 100. Tabelid. Vt. samas: Enn Heinsoo. Esikoha tõi kontori müük; Proeksperdil suund välisturgudele;¡ Ida-Eesti turg arenevale firmale kitsas. Diagrammid. Nimekiri: Omanikud

  11. Marine genomics

    DEFF Research Database (Denmark)

    Oliveira Ribeiro, Ângela Maria; Foote, Andrew David; Kupczok, Anne

    2017-01-01

    Marine ecosystems occupy 71% of the surface of our planet, yet we know little about their diversity. Although the inventory of species is continually increasing, as registered by the Census of Marine Life program, only about 10% of the estimated two million marine species are known. This lag......-throughput sequencing approaches have been helping to improve our knowledge of marine biodiversity, from the rich microbial biota that forms the base of the tree of life to a wealth of plant and animal species. In this review, we present an overview of the applications of genomics to the study of marine life, from...

  12. TOP2017 Experimental summary

    CERN Document Server

    Giammanco, Andrea

    2017-01-01

    Thanks to the unprecedentedly fast accumulation of high-energy data at the LHC during the ongoing Run~2, most of the traditional top-quark analyses are experiencing the luxury of having to worry about how to punch through the ``Systematics Wall'', and think about new ways to maximize the utility of their data. New processes involving top quarks are being studied for the first time, and the good old pair-production processes are being explored in unusual settings, such as collisions involving heavy ions, or ``reference data'' collected by the LHC at relatively low centre-of-mass energy. The TOP2017 conference featured 37 talks delivered by experimental physicists, including seven in the ``Young Scientists Forum'' where young colleagues were given the opportunity to elaborate more deeply than usual on their own work. As it is impossible to do justice to all the experimental resu...

  13. Top-ophilia

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris; /Fermilab

    2008-01-01

    Almost from the moment in June 1977 when the discovery of the Upsilon resonance revealed the existence of what we now call the bottom quark, physicists began searching for its partner. Through the years, as we established the electric charge and weak isospin of the b-quark, and detected the virtual influence of its mate, it became clear that the top quark must exist. Exactly at what mass, we couldn't say, but we knew just how top events would look. We also knew that top events would be rare--if the Tevatron could make them at all--and that picking out the events would pose a real challenge for the experimenters and their detectors.

  14. 76 FR 25479 - Taking and Importing Marine Mammals; Military Training Activities Conducted Within the Gulf of...

    Science.gov (United States)

    2011-05-04

    ... Hearing of Marine Animals Passive Acoustic Detection, Classification, and Tracking of Marine Mammals The... impact of MFAS and underwater explosive detonations on marine animals. Top priorities of the ICMP include.... Furthermore, these large-grouped gregarious animals are very likely to be detected by Marine Mammal Observers...

  15. Marine biology

    International Nuclear Information System (INIS)

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index

  16. Marine fog: a review

    Science.gov (United States)

    Koračin, Darko; Dorman, Clive E.; Lewis, John M.; Hudson, James G.; Wilcox, Eric M.; Torregrosa, Alicia

    2014-01-01

    The objective of this review is to discuss physical processes over a wide range of spatial scales that govern the formation, evolution, and dissipation of marine fog. We consider marine fog as the collective combination of fog over the open sea along with coastal sea fog and coastal land fog. The review includes a history of sea fog research, field programs, forecasting methods, and detection of sea fog via satellite observations where similarity in radiative properties of fog top and the underlying sea induce further complexity. The main thrust of the study is to provide insight into causality of fog including its initiation, maintenance, and destruction. The interplay between the various physical processes behind the several stages of marine fog is among the most challenging aspects of the problem. An effort is made to identify this interplay between processes that include the microphysics of fog formation and maintenance, the influence of large-scale circulation and precipitation/clouds, radiation, turbulence (air-sea interaction), and advection. The environmental impact of marine fog is also addressed. The study concludes with an assessment of our current knowledge of the phenomenon, our principal areas of ignorance, and future lines of research that hold promise for advances in our understanding.

  17. TOP LINAC design

    International Nuclear Information System (INIS)

    Picardi, L.; Ronsivalle, C.; Vignati, A.

    1997-11-01

    The report describes a linear accelerator for protons named TOP LINAC designed for the TOP (Terapia Oncologica con Protoni, Oncological Protontherapy) project launched by the Italian National Institute of Health (Istituto Superiore di Sanita', ISS) to explore in collaboration with the biggest Oncological Hospital in Rome (Istituto Regina Elena, IRE) the potentialities of the therapy with accelerated protons and establish guide lines for the application of this new type of radiotherapy in comparison with the more traditional electron and x-rays radiotherapy. The concept of a compact accelerator for protontherapy applications bore within the Italian Hadrontherapy Collaboration (TERA Collaboration) with the aim to diffuse the protontherapy on the National territory. The ISS program plans to use the TOP linac proton beam also for production of PET (Positron Emission Tomography) radioisotopes and radiobiology studies. Official agreements are in course between ISS and ENEA which provides its experience in the industrial and medical accelerators for the design and the construction of the TOP linac. The accelerator that will be the first 3 GHz proton linac in the world, will be composed of a 428.3 MHz 7 Me V RFQ + DTL injector followed by a 7-65 Me V section of a 3 GHz SCDTL structure and a 65 - 200 Me V variable energy SCL 3 GHz structure. In particular the SCDTL section uses a highly innovative accelerating structure patented by ENEA. In this report the clinical and physical requests are discussed and a preliminary design of the whole machine is given

  18. Top emitting white OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, Patricia; Luessem, Bjoern; Leo, Karl [Technische Universitaet Dresden, Institut fuer Angewandte Photophysik, George-Baehr-Strasse 1, 01069 Dresden (Germany)

    2009-07-01

    Top emitting organic light emitting diodes (TOLEDs) provide a number of interesting opportunities for new applications, such as the opportunity to fabricate ITO-free devices by using opaque substrates. This makes it possible to manufacture low cost OLEDs for signage and lighting applications. A general top emitting device consists of highly reflecting metal contacts as anode and semitransparent cathode, the latter one for better outcouling reasons. In between several organic materials are deposited as charge transporting, blocking, and emission layers. Here, we show a top emitting white organic light emitting diode with silver electrodes arranged in a p-i-n structure with p- and n-doped charge transport layers. The centrical emission layer consists of two phosphorescent (red and green) and one fluorescent (blue) emitter systems separated by an ambipolar interlayer to avoid mutual exciton quenching. By adding an additional dielectric capping layer on top of the device stack, we achieve a reduction of the strong microcavity effects which appear due to the high reflection of both metal electrodes. Therefore, the outcoupled light shows broad and nearly angle-independent emission spectra, which is essential for white light emitting diodes.

  19. Top quark theory

    Indian Academy of Sciences (India)

    2012-10-04

    Oct 4, 2012 ... The theoretical aspects of a number of top quark properties such as ... to the quadratic divergences of the Higgs self-energy, while yet, ..... given in the literature, each with the aim of recovering a well-behaved expansion in αs.

  20. Top quark properties

    Indian Academy of Sciences (India)

    eter for the tests of the electroweak theory, since radiative corrections to many ... The uncertainty due to jet energy scale (JES) is the dominating systematic .... In the Standard Model, the charge of the top quark is predicted to be that of a normal up- ..... non-negative and f+ + f0 < 1, and the star marks the expectation from the ...

  1. Anomalous top magnetic couplings

    Indian Academy of Sciences (India)

    2012-11-09

    Nov 9, 2012 ... Corresponding author. E-mail: remartinezm@unal.edu.co. Abstract. The real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the tbW vertex in the Standard Model (SM) are computed. Keywords. Top; anomalous. PACS Nos 14.65.Ha; 12.15 ...

  2. CPT analysis with top physics

    Energy Technology Data Exchange (ETDEWEB)

    Cembranos, Jose A. R., E-mail: cembra@fis.ucm.es [Universidad Complutense de Madrid, Departamento de Fisica Teorica I (Spain)

    2013-03-15

    We discuss the possibility of observing CPT violation from top anti-top production in hadronic colliders. We study a general approach by analyzing constraints on the mass difference between the top and anti-top quarks. We present current bounds from Tevatron data, and comment on the prospects for improving these bounds at the LHC and the ILC.

  3. Top Quark Properties at Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Lysák, Roman [Prague, Inst. Phys.

    2017-11-27

    The latest CDF and D0 experiment measurements of the top quark properties except the top quark mass are presented. The final combination of the CDF and D0 forward-backward asymmetry measurements is shown together with the D0 measurements of the inclusive top quark pair cross-section as well as the top quark polarization.

  4. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high ... or by any means without permission in writing from the copyright holder. ..... Journal of Chemical Engineering Research and Design 82 ... Indian Ocean Marine Science Association Technical.

  5. Marine Biomedicine

    Science.gov (United States)

    Bang, Frederik B.

    1977-01-01

    Describes early scientific research involving marine invertebrate pathologic processes that may have led to new insights into human disease. Discussed are inquiries of Metchnikoff, Loeb, and Cantacuzene (immunolgic responses in sea stars, horseshoe crabs, and marine worms, respectively). Describes current research stemming from these early…

  6. Marine Biology

    Science.gov (United States)

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  7. Landfill Top Covers

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Kjeldsen, Peter

    2011-01-01

    The purpose of the final cover of a landfill is to contain the waste and to provide for a physical separation between the waste and the environment for protection of public health. Most landfill covers are designed with the primary goal to reduce or prevent infiltration of precipitation...... into the landfill in order to minimize leachate generation. In addition the cover also has to control the release of gases produced in the landfill so the gas can be ventilated, collected and utilized, or oxidized in situ. The landfill cover should also minimize erosion and support vegetation. Finally the cover...... is landscaped in order to fit into the surrounding area/environment or meet specific plans for the final use of the landfill. To fulfill the above listed requirements landfill covers are often multicomponent systems which are placed directly on top of the waste. The top cover may be placed immediately after...

  8. Computing Z-top

    International Nuclear Information System (INIS)

    Kashani-Poor, A.K.

    2014-01-01

    The topological string presents an arena in which many features of string theory proper, such as the interplay between world-sheet and target space descriptions or open-closed duality, can be distilled into computational techniques which yield results beyond perturbation theory. In this thesis, I will summarize my research activity in this area. The presentation is organized around computations of the topological string partition function Z-top based on various perspectives on the topological string. (author)

  9. Top of the list

    International Nuclear Information System (INIS)

    Cameron, A.; Vries, E. de

    2006-01-01

    In this article the authors look at how the major turbine suppliers fared in the year 2005, and look forward to 2006 which could be the best ever for the wind industry. The world wind turbine market continues to be dominated by ten major companies, who together account for almost 100% of the total global market. Although there are some new companies on the horizon it is the ten major companies that the authors concentrate on, in particular the top three, Vestas, Gamesa and Enercon who between them control 66% of the market. They give their overall report on business in 2005 and give their predictions for 2006. By far the leading wind turbine supplier is the Danish Company Vestas, accounting for over 30% of the global market. However all of the top ten companies report a successful year and all are expecting an even better 2006. This paper also reports on potential newcomers to the industry, one of these is California-based Clipper Windpower which commenced manufacturing the 2.5 MW Liberty turbine in Iowa. Chinese manufacturer Goldwind is also looking to enter the market having acquired a licence to produce the Vensys 1.2 MW turbine. It may well be that changes are on the way, there will be jockeying for position at the top and newcomers will want to make an impression on the market

  10. Top quark measurements at ATLAS

    CERN Document Server

    Grancagnolo, Sergio; The ATLAS collaboration

    2017-01-01

    The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, this gives us the unique opportunity to probe the properties of bare quarks at the Large Hadron Collider. This talk will present highlights of a few recent precision measurements by the ATLAS Collaboration of the top quark using 13 TeV and 8 TeV collision data: top-quark pair and single top production cross sections including differential distributions will be presented alongside top quark properties measurements. These measurements, including results using boosted top quarks, probe our understanding of top quark production in the TeV regime. Measurements of the top quark mass and searches for rare top quark decays are also presented.

  11. Top quark measurements at ATLAS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00041686; The ATLAS collaboration

    2017-01-01

    The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, it allows us to probe the properties of bare quarks at the Large Hadron Collider. Highlights of a few recent precision measurements by the ATLAS Collaboration of the top quark using 13 TeV and 8 TeV collision data will be presented: top-quark pair and single top production cross sections including differential distributions will be presented alongside measurements of top-quark properties, including results using boosted top quarks, probe our understanding of top-quark production in the TeV regime. Measurements of the top-quark mass and searches for rare top quark decays are also presented.

  12. Naisjuhtidega ettevõtete TOP 100

    Index Scriptorium Estoniae

    2004-01-01

    Naisjuhtidega ettevõtete TOP 100. Käibe TOP 20. Käibe kasvu TOP 20. Kasumi TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Riigi- ja kohaliku omavalitsuse asutuste naisjuhtide TOP 25. Riigi- ja kohaliku omavalitsuse asutuste eelarve TOP 25. Riigi- ja kohaliku omavalitsuse asutuste töötajate arvu TOP 25. Riigi- ja kohaliku omavalitsuse asutuste naisjuhtide palga TOP 25

  13. An A-train and MERRA view of cloud, thermodynamic, and dynamic variability within the subtropical marine boundary layer

    Directory of Open Access Journals (Sweden)

    B. H. Kahn

    2017-08-01

    Full Text Available The global-scale patterns and covariances of subtropical marine boundary layer (MBL cloud fraction and spatial variability with atmospheric thermodynamic and dynamic fields remain poorly understood. We describe an approach that leverages coincident NASA A-train and the Modern Era Retrospective-Analysis for Research and Applications (MERRA data to quantify the relationships in the subtropical MBL derived at the native pixel and grid resolution. A new method for observing four subtropical oceanic regions that capture transitions from stratocumulus to trade cumulus is demonstrated, where stratocumulus and cumulus regimes are determined from infrared-based thermodynamic phase. Visible radiances are normally distributed within stratocumulus and are increasingly skewed away from the coast, where trade cumulus dominates. Increases in MBL depth, wind speed, and effective radius (re, and reductions in 700–1000 hPa moist static energy differences and 700 and 850 hPa vertical velocity correspond with increases in visible radiance skewness. We posit that a more robust representation of the cloudy MBL is obtained using visible radiance rather than retrievals of optical thickness that are limited to a smaller subset of cumulus. The method using the combined A-train and MERRA data set has demonstrated that an increase in re within shallow cumulus is strongly related to higher MBL wind speeds that further correspond to increased precipitation occurrence according to CloudSat, previously demonstrated with surface observations. Hence, the combined data sets have the potential of adding global context to process-level understanding of the MBL.

  14. Study of top and anti-top mass difference

    CERN Document Server

    Leedumrongwatthanakun, Saroch

    2013-01-01

    The invariance of the standard model under CPT transformations leads to the equality of particle and antiparticle masses. The recent measurements performed by the CMS experiment on the top anti-top mass difference are a test of such symmetry. In this work non-perturbative QCD effects, which may eventually lead to an apparent difference in the mass of a top and anti-top quark, are studied.

  15. Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific near-coastal marine stratocumulus during VOCALS-REx

    OpenAIRE

    Zheng, X.; Albrecht, B.; Jonsson, H. H; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

    2011-01-01

    The article of record as published may be found at http://dx.doi.org/10.5194/acp-11-9943-2011 Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud- Atmosphere-Land Study- Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) ...

  16. Tekstiilitööstuse TOP 47

    Index Scriptorium Estoniae

    2005-01-01

    Tekstiilitööstuse TOP 47; Käibe TOP 35; Kasumi TOP 35; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Varade tootlikkuse TOP 20; Tekstiilitööstuse TOP-i firmade üld- ja finantsandmed

  17. Rõivatööstuse TOP 50

    Index Scriptorium Estoniae

    2005-01-01

    Rõivatööstuse TOP 50; Käibe TOP 35; Kasumi TOP 35; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20; Rõivatööstuse TOP-i firmade üld- ja finantsandmed

  18. Eesti Ettevõtete TOP 100

    Index Scriptorium Estoniae

    2002-01-01

    TOP 100. Käibe TOP 500. Käibe kasvu TOP 100. Kasumi TOP 100. Kasumi kasvu TOP 100. Rentaabluse TOP 100. Omakapitali tootlikkuse TOP 100. Eesti edukamate ettevõtete üldandmed. Eesti edukamate ettevõtete finantsnäitajad. Valdkonna ja maakonna TOP-ide edukamate ettevõtete finantsnäitajad

  19. Marine Science

    African Journals Online (AJOL)

    between humans and the coastal and marine environment. ... The journal has a new and more modern layout, published online only, and the editorial .... the population structure of Platorchestia fayetta sp. nov. and their interaction with the.

  20. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the ... tidal height and amplitude can influence light penetra- ...... to environmental parameters in cage culture area of Sepanggar Bay, Malaysia.

  1. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ... consist of special issues on major events or important thematic issues. ... of sources, including plant and animal by- products.

  2. Marine biotoxins

    National Research Council Canada - National Science Library

    2004-01-01

    ... (ciguatera fish poisoning). It discusses in detail the causative toxins produced by marine organisms, chemical structures and analytical methods, habitat and occurrence of the toxin-producing organisms, case studies and existing regulations...

  3. Marine Science

    African Journals Online (AJOL)

    pod diversity and distribution are important especially since studies on marine biodiversity are scarce .... Method II –. Zamoum &. Furla (2012) protocol. Method III. – Geist et al (2008) protocol ..... Public Library Of Science One 8: 51273.

  4. Marine pollution

    International Nuclear Information System (INIS)

    Clark, R.B.

    1992-01-01

    The effects of petroleum, waste materials, halogenated hydrocarbons, radioactivity and heat on the marine ecosystem, the fishing industry and human health are discussed using the example of the North Sea. (orig.) [de

  5. Marine Science

    African Journals Online (AJOL)

    No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form ... to optimize nucleic acid extraction protocols from marine gastropods, present an ...... Greenfield., Gomez E, Harvell CD, Sale PF, Edwards.

  6. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high ..... circulation patterns include the nutrient-rich Somali ...... matical Structures in Computer Science 24: e240311.

  7. Marine insects

    National Research Council Canada - National Science Library

    Cheng, Lanna

    1976-01-01

    .... Not only are true insects, such as the Collembola and insect parasites of marine birds and mammals, considered, but also other kinds of intertidal air-breathing arthropods, notably spiders, scorpions...

  8. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue .... shell growth is adversely affected. ... local stressors in action, such as ocean acidification ..... that the distribution of many intertidal sessile animals.

  9. Treasury Offset Program (TOP) MI

    Data.gov (United States)

    Social Security Administration — The TOP MI helps OPSOS coordinate TOP case processing in the regions. The MI also helped communicate our progress and findings to BFQM and ORDP, as well as the ACOSS.

  10. Top Quark Physics with CMS

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    Higgs mechanism. There are various hints at deviations from the Standard Model expectation which have been observed recently by Tevatron experiments in top final states. Several signatures of new physics accessible at the LHC either suffer from top-quark production as a significant background or contain top quarks themselves. In this talk, we present results on top quark physics obtained from the first LHC data collected by the CMS experiment.They include measurements of the top pair production cross section in various channels and their combination, measurements of the top quark mass, the single top cross section, a search for new particles decaying into top pairs, and a first look at the charge asymmetry.

  11. Top production at hadron colliders

    Indian Academy of Sciences (India)

    New results on top quark production are presented from four hadron collider experiments: CDF and D0 at the Tevatron, and ATLAS and CMS at the LHC. Cross-sections for single top and top pair production are discussed, as well as results on the top–antitop production asymmetry and searches for new physics including ...

  12. Single top t-channel

    CERN Document Server

    Faltermann, Nils

    2017-01-01

    The production of single top quarks allows to study the interplay of top quark physics and the electroweak sector of the standard model. Deviations from predictions can be a hint for physics beyond the standard model. The t-channel is the dominant production mode for single top quarks at the LHC. This talk presents the latest measurements from the ATLAS and CMS collaborations.

  13. Forward Top Physics at LHCb

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    The first Run 2 measurement of top pair production in the dilepton channel at 13 TeV will be presented, along with previous Run 1 measurements in final states accessible to both single top and top pair production. Heavy flavour tagging strategies at LHCb will also be discussed.

  14. Marine ARM GPCI Investigation of Clouds (MAGIC) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Ernie R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-12-01

    The Marine ARM GPCI Investigation of Clouds (MAGIC) field campaign, which deployed the second ARM Mobile Facility (AMF2) aboard the Horizon Lines cargo container ship Spirit as it ran its regular route between Los Angeles, California and Honolulu, Hawaii, measured properties of clouds and precipitation, aerosols, radiation, and atmospheric, meteorological, and oceanic conditions with the goal of obtaining statistics of these properties to achieve better understanding of the transition between stratocumulus and cumulus cloud regimes that occur in that region. This Sc-Cu transition is poorly represented in models, and a major reason for this is the lack of high-quality and comprehensive data that can be used to constrain, validate, and improve model representation of the transition. MAGIC consisted of 20 round trips between Los Angeles and Honolulu, and thus over three dozen transects through the transition, totaling nearly 200 days at sea between September, 2012 and October, 2013. During this time MAGIC collected a unique and unprecedented data set, including more than 550 successful radiosonde launches. An Intensive Observational Period (IOP) occurred in July, 2013 during which more detailed measurements of the atmospheric structure were made. MAGIC was very successful in its operations and overcame numerous logistical and technological challenges, clearly demonstrating the feasibility of a marine AMF2 deployment and the ability to make accurate measurements of clouds and precipitation, aerosols, and radiation while at sea.

  15. The top ten.

    Science.gov (United States)

    Davis, C

    1985-10-01

    3 lists were compiled to answer the question of what countries have experienced the most population growth from World War II to the present. The 1st list includes the 10 countries which accounted for the largest gain in world population. The 2nd list shows the 10 countries with the highest growth rates of the 150 or so most populous countries in the world. The last list also shows countries ranked by growth rate but is limited to those with a current population of at least 10 million. To deal with the fact that some countries did not exist at 1 of the reference points, a set of estimates for 1940 provided a convenient starting point. China and India headed the list of countries ranked by absolute gains. They contributed half again as much growth as the next 8 nations combined. Altogether Asia, home to almost 60% of the world's population, captured 5 of the top 10 slots. The US and the USSR are the only developed countries on the list. The Soviet Union also presents the 1st case on the list of a country with a lower ranking in population gain (6th) than in absolute size in 1985 (3rd). Many of the population giants of 1940 (Japan, Great Britain, Germany, France, and Italy) are not on the list. Despite large base populations, their growth has been slow in the intervening years. All of the countries with the highest growth rates experienced over 3% annual average growth during the last 45 years: Kuwait, United Arab Emirates, Libya, Venezuela, Costa Rica, Kenya, Ivory Coast, Mexico, Honduras, and Syria. The influence of immigration is much in evidence in this list and explains otherwise unachievable rates of growth. The top 4 countries in annual rates of growth are all oil exporters. The top 3 countries in the 3rd list -- Venezuela, Kenya, and Mexico -- are carried over from the 2nd list, sharing the characteristics of rapid population growth and substantial base populations. The geographic mix of this list is notable. Asia, Africa, and Latin America each have at least

  16. Top quark physics

    International Nuclear Information System (INIS)

    Menzione, A.

    1995-10-01

    Most of the material presented in this report, comes from contributions to the parallel session PL20 of this conference. We summarise the experimental results of direct production of Top quarks, coming from the CDF and C0 Collaborations at Fermilab, and compare these results to what one expects within current theoretical understanding. Particular attention is given to new results such as all hadronic modes of t bar t decay. As far as the mass is concerned, a comparison is made with precision measurements of related quantities, coming from LEP and other experiments. An attempt is made to look at the medium-term future and understand which variables and with what accuracy one can measure them with increased integrated luminosity

  17. Top quark pair production and top quark properties at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Chang-Seong [INFN, Pisa

    2016-06-02

    We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.

  18. Toitlustusettevõtete TOP 30 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Toitlustusettevõtete TOP 30 aastal 2002. Käibe TOP 30. Kasumi TOP 30. Käibe kasvu TOP 30. Kasumi kasvu TOP 30. Rentaabluse TOP 30. Omakapitali tootlikkuse TOP 30. Toitlustusettevõtete üldandmed. Toitlustusettevõtete finantsandmed

  19. Hiiumaa ettevõtete TOP 50

    Index Scriptorium Estoniae

    2005-01-01

    Hiiumaa ettevõtete TOP 50; Käibe TOP 35; Kasumi TOP 35; Hiiumaa ettevõtete üld- ja finantsandmed; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20. Vt samas: Teeli Remmalg: Hiiumaal jätkub plastitööstuse võidumarss

  20. The search for the top quark

    International Nuclear Information System (INIS)

    Barbaro-Galtieri, A.

    1989-03-01

    This paper discusses the following topics: top search in the near future, general remarks, top search at HERA, searching for the top quarks at the Z 0 machines, finding the top at Lep II, top search in UA2, top search in UA1, and top search at CDF. 58 refs., 38 figs

  1. Toiduainetööstuste TOP 100

    Index Scriptorium Estoniae

    2006-01-01

    Toiduainetööstuse TOP. Vt. samas: Käibe TOP 10; Käibekasvu TOP 10; Kasumi TOP 10; Kasumi kasvu TOP 10; Rentaabluse TOP 10; Omakapitali tootlikkuse TOP 10; Toiduainetööstuse üld- ja finantsandmed

  2. Online-kaubanduse TOP aastal 2003

    Index Scriptorium Estoniae

    2004-01-01

    Online-kaubanduse TOP aastal 2003. Käibe TOP 5. Käibe kasvu TOP 5. Rentaabluse TOP 5. Kasumi TOP 5. Kasumi kasvu TOP 5. Omakapitali tootlikkuse TOP 5. Lisa: TOPi koostamise metoodika. Online-kaubanduse firmade üldandmed. Online kaubanduse firmade finantsandmed

  3. TopView - ATLAS top physics analysis package

    CERN Document Server

    Shibata, A

    2007-01-01

    TopView is a common analysis package which is widely used in the ATLAS top physics working group. The package is fully based on the official ATLAS software Athena and EventView and playing a central role in the collaborative analysis model. It is a functional package which accounts for a broad range issues in implementing physics analysis. As well as being a modular framework suitable as a common workplace for collaborators, TopView implements numerous analysis tools including a complete top-antitop reconstruction and single top reconstruction. The package is currently used to produce common ntuple from Monte Carlo production and future use cases are under rapid development. In this paper, the design and ideas behind TopView and the performance of the analyses implemented in the package are presented with detailed documentation of the contents and instruction for using the package.

  4. Otters, Marine

    Science.gov (United States)

    Estes, James A.; Bodkin, James L.; Ben-David, M.; Perrin, William F.; Würsing, Bernd; Thewissen, J.G.M.

    2009-01-01

    The otters (Mustelidae; Lutrinae) provide an exceptional perspective into the evolution of marine living by mammals. Most extant marine mammals (e.g. the cetaceans, pinnipeds, and sirenians) have been so highly modified by long periods of selection for life in the sea that they bear little resemblance to their terrestrial ancestors. Marine otters, in contrast, are more recent expatriates from freshwater habitats and some species still live in both environments. Contrasts among species within the otters, and among the otters, terrestrial mammals, and the more highly adapted pinnipeds and cetaceans provide powerful insights into mammalian adaptations to life in the sea (Estes, 1989). Among the marine mammals, sea otters (Enhydra lutris, Fig. 1) provide the clearest understanding of consumer-induced effects on ecosystem function. This is due in part to opportunities provided by history and in part to the relative ease with which shallow coastal systems where sea otters live can be observed and studied. Although more difficult to study than sea otters, other otter species reveal the connectivity among the marine, freshwater, and terrestrial systems. These three qualities of the otters – their comparative biology, their role as predators, and their role as agents of ecosystem connectivity – are what make them interesting to marine mammalogy.The following account provides a broad overview of the comparative biology and ecology of the otters, with particular emphasis on those species or populations that live in the sea. Sea otters are features prominently, in part because they live exclusively in the sea whereas other otters have obligate associations with freshwater and terrestrial environments (Kenyon, 1969; Riedman and Estes, 1990).

  5. Marine Battlefields

    DEFF Research Database (Denmark)

    Harðardóttir, Sara

    as they are an important food source for various marine animals. For both phytoand zooplankton predation is a major cause of mortality, and strategies for protection or avoidance are important for survival. Diatoms of the genera Nitzschia and Pseudo-nitzschia are known to produce a neuro-toxin, domoic acid (DA). Despite......Phytoplankton species are photosynthetic organisms found in most aquatic habitats. In the ocean, phytoplankton are tremendously important because they produce the energy that forms the base of the marine food web. Zooplankton feed on phytoplankton and mediate the energy to higher trophic levels...

  6. Naisjuhtidega ettevõtete TOP 70

    Index Scriptorium Estoniae

    2003-01-01

    Naisjuhtidega ettevõtete TOP 70. Käibe TOP 30. Käibe kasvu TOP 30. Kasumi TOP 30. Kasumi kasvu TOP 30. Rentaabluse TOP 30. Omakapitali tootlikkuse TOP 30. Nais- ja meesjuhtidega ettevõtted 2001. aasta 500 edukama ettevõtte hulgas. Naistegevjuhtidega firmade TOP 2001 ja 2002. Riigi- ja kohaliku omavalitsuse asutuste naisjuhtide TOP 20. Riigi- ja kohaliku omavalitsuse asutuste eelarve TOP 20. Riigi- ja kohaliku omavalitsuse asutuste töötajate arvu TOP 20. Naistegevjuhtidega firmade osakaal 2001. aastal. Riigi- ja kohaliku omavalitsuse asutuste naisjuhtide aastapalga TOP 20. Kommenteerib Tiina Raitviir.

  7. Financial top 100

    International Nuclear Information System (INIS)

    Jaremko, G.

    1999-01-01

    The way in which the oil industry has rebounded from a difficult financial year was discussed. In 1998, oil prices fell by about 30 per cent from 1997 prices to average US$14.40. In the second quarter of 1999, the rebounding international markets raised oil prices by about one-third to an average US$17.60. Recent surveys have shown that the oil and gas industry will experience major changes in the decade ahead. It was forecasted that in 25 years, total Canadian oil production could near three million barrels per day, an increase of 36 per cent from today's 2.2 million. However, as conventional reserves are running out, production of conventional oil is expected to be diminished by about two-thirds. Naturally-occurring, light refinery-ready oil is forecasted to come mostly from the east coast, whereas western output will be dominated by oil sands. Natural gas will continue to be a huge growth opportunity in the west because of new pipeline expansions and exports to the United States. This paper presented a list of Canada's financial top 100 oil and gas companies which emerged with the best endurance. The list included statistics from 1997 and 1998 for gross revenues, total assets, net income, cash/operating activities, capital expenditures, closing share prices (with percentage change), and market capitalization. 1 fig., 1 tab

  8. Our top priority

    CERN Multimedia

    2012-01-01

    After three years of LHC running, we are still at the beginning of a long research programme with our flagship facility, and hopefully 4 July 2012 will go down in history as the date of one of many landmark discoveries spanning several years. CERN’s top priority for the next decade and more is the full exploitation of the LHC. With speculation about potential future facilities mounting in the light of the discovery of a new Higgs-like particle, it’s important to state that most clearly. Of course, this will rely on continued global collaboration, and it’s important that CERN engage constructively with other regions.   It is important to plan ahead, particularly since the lead times for new projects in particle physics are long, and our field is increasingly global in nature. That’s why the European particle physics community is currently engaged in updating its long-term strategy. Planning ahead allowed us to be ready technologically to build the LHC whe...

  9. Participative Design With Top Management

    DEFF Research Database (Denmark)

    Simonsen, Jesper

    2004-01-01

    meetings aimed at aligning top management with the supplier’s analysis. The article describes the MUST method’s anchoring principle and the technique of problem mapping supporting this principle. This participatory approach resulted in mutual learning processes with top management which is rarely reported...... on in the PD community. Top management participated by reviewing, challenging, and reformulating the IT designers’ central suppositions, assumptions, and hypotheses related to the causal relation between identified problems and suggested solutions....

  10. Marine Science

    African Journals Online (AJOL)

    Science. The journal has a new and more modern layout, published online only, and the editorial. Board was increased to include more disciplines pertaining to marine sciences. While important chal- lenges still lie ahead, we are steadily advancing our standard to increase visibility and dissemination throughout the global ...

  11. Marine Mammals.

    Science.gov (United States)

    Meith, Nikki

    Marine mammals have not only fascinated and inspired human beings for thousands of years, but they also support a big business by providing flesh for sea-borne factories, sustaining Arctic lifestyles and traditions, and attracting tourists to ocean aquaria. While they are being harpooned, bludgeoned, shot, netted, and trained to jump through…

  12. Marine Science

    African Journals Online (AJOL)

    Mauritius Marine Conservation Society through their. Abstract. While no populations of seals are resident in the tropical Indian Ocean, vagrant animals are occasionally sighted in the region. Here we detail two new sightings of pinnipeds in the Mascarene Islands (Mauritius, Reunion and Rodri- gues) since 1996 and review ...

  13. Marine Science

    African Journals Online (AJOL)

    J O U R N A L O F. Marine Science. Coral reefs of Mauritius in a changing global climate ..... in confined aquifers, and a lesser influence in uncon- fined systems. On the ... massive cloud cover during the critical months, some. 70% bleaching ...

  14. Marine Science

    African Journals Online (AJOL)

    Copy Editor Timothy Andrew. Published ... 2007; Zhou et al., 2009) and they play an important role in the ... At both sites, zonal variation in TMPB was evident with significantly higher C-biomass closer to ... ton is considered to be an essential parameter in eco- systems ...... logical significance of toxic marine dinoflagellates.

  15. Marine Science

    African Journals Online (AJOL)

    sustainable coastal development in the region, as well as contributing to the ... between humans and the coastal and marine environment. ... exploitation for timber, fuel wood, aquaculture, urban. Abstract. Given the high dependence of coastal communities on natural resources, mangrove conservation is a challenge in.

  16. Marine Science

    African Journals Online (AJOL)

    No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means ... USA/Norway ... The last couple of years have been a time of change for the Western Indian Ocean Journal of Marine.

  17. Marine Science

    African Journals Online (AJOL)

    Chief Editor José Paula | Faculty of Sciences of University of Lisbon, Portugal. Copy Editor Timothy Andrew. Published biannually. Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high quality research generated in the Western Indian Ocean (WIO) ...

  18. Boosted top: experimental tools overview

    CERN Document Server

    Usai, Emanuele

    2015-01-01

    An overview of tools and methods for the reconstruction of high-boost top quark decays at the LHC is given in this report. The focus is on hadronic decays, in particular an overview of the current status of top quark taggers in physics analyses is presented. The most widely used jet substructure techniques, normally used in combination with top quark taggers, are reviewed. Special techniques to treat pileup in large cone jets are described, along with a comparison of the performance of several boosted top quark reconstruction techniques.

  19. Could stops lighten the top?

    International Nuclear Information System (INIS)

    Bilal, A.; Ellis, J.; Fogli, G.L.

    1990-01-01

    The analysis of the presently available electroweak data including radiative corrections in the standard model suggests that the top quark weighs more than the Z 0 . We examine whether squark loops in the minimal supersymmetric model, particularly those involving stops (partners of the top quark), could reduce substantially the preferred range of top quark masses. Given the present lower bounds on squark masses, we find that stop effects can reduce the central value of m t by at most a few GeV, although they do make a very heavy top quark increasingly unlikely. (orig.)

  20. Wave Engine Topping Cycle Assessment

    Science.gov (United States)

    Welch, Gerard E.

    1996-01-01

    The performance benefits derived by topping a gas turbine engine with a wave engine are assessed. The wave engine is a wave rotor that produces shaft power by exploiting gas dynamic energy exchange and flow turning. The wave engine is added to the baseline turboshaft engine while keeping high-pressure-turbine inlet conditions, compressor pressure ratio, engine mass flow rate, and cooling flow fractions fixed. Related work has focused on topping with pressure-exchangers (i.e., wave rotors that provide pressure gain with zero net shaft power output); however, more energy can be added to a wave-engine-topped cycle leading to greater engine specific-power-enhancement The energy addition occurs at a lower pressure in the wave-engine-topped cycle; thus the specific-fuel-consumption-enhancement effected by ideal wave engine topping is slightly lower than that effected by ideal pressure-exchanger topping. At a component level, however, flow turning affords the wave engine a degree-of-freedom relative to the pressure-exchanger that enables a more efficient match with the baseline engine. In some cases, therefore, the SFC-enhancement by wave engine topping is greater than that by pressure-exchanger topping. An ideal wave-rotor-characteristic is used to identify key wave engine design parameters and to contrast the wave engine and pressure-exchanger topping approaches. An aerodynamic design procedure is described in which wave engine design-point performance levels are computed using a one-dimensional wave rotor model. Wave engines using various wave cycles are considered including two-port cycles with on-rotor combustion (valved-combustors) and reverse-flow and through-flow four-port cycles with heat addition in conventional burners. A through-flow wave cycle design with symmetric blading is used to assess engine performance benefits. The wave-engine-topped turboshaft engine produces 16% more power than does a pressure-exchanger-topped engine under the specified topping

  1. Status of the top quark: Top production cross section and top properties

    Energy Technology Data Exchange (ETDEWEB)

    Boisvert, V.; /Rochester U.

    2006-08-01

    This report describes the latest cross section and property measurements associated with the top quark at the Tevatron Run II. The largest data sample used is 760 pb{sup -1} of integrated luminosity. Due to its large mass, the top quark might be involved in the process of electroweak symmetry breaking, making it a useful probe for signs of new physics.

  2. New directions in top physics

    Energy Technology Data Exchange (ETDEWEB)

    Schell, Torben Karl

    2017-02-01

    The top quark plays an important role for many aspects of particle physics. The coupling of the Higgs boson to top quarks is a key parameter to probe electroweak symmetry breaking and is important for the evolution of the Higgs potential to high energies. In addition, many models of physics beyond the Standard Model predict heavy particles that decay to top-quark pairs. Furthermore, the unexplained hierarchy of fermion masses culminates in the large top-quark mass. In this thesis, we consider resonance searches based on top quarks in the fully hadronic final state. We employ multivariate techniques in form of boosted decision trees and add several improvements to the original HEPTopTagger algorithm. These modifications and extensions result in the new HEPTopTagger2. The achieved improvements are used to estimate the precision to which the top Yukawa coupling can be measured at a future 100 TeV proton-proton collider in the fully hadronic final state of t anti tH production. We find that at such a collider a precision measurement of the top Yukawa coupling to 1% should be possible. The statistical precision is backed up by demonstrating that in the ratio σ(t anti tH)/σ(t anti tZ) theoretical uncertainties cancel to below-percent level. Finally, we propose a Froggatt-Nielsen-type model to address the hierarchy of fermion masses in the Standard Model and determine current and projected bounds on the available parameter space.

  3. Top-down cascades in lakes and oceans: Different perspectives but same story?

    KAUST Repository

    Hessen, Dag Olav

    2014-05-16

    While top-down cascades from fish to phytoplankton have been a core topic in limnology for the past four decades, it has attracted far less interest in marine ecology. This is partly for historical reasons, since lake studies have been motivated by the ability to regulate algal blooms induced by cultural eutrophication, while marine studies have been more oriented towards fish yield and thus bottom-up processes. Also freshwaters are closed ecosystems with lower diversity and complexity, making models and predictions on trophic levels and interactions comparatively simpler. Here, we compare some key properties of freshwater and marine top-down cascades and argue that despite some striking differences, the large number of freshwater studies may pose valuable insights also for marine systems. Moreover, we argue that there is an urgent need for more focus on top-down cascades in marine systems that address how top predators or fishing may propagate through the food web and impact autotrophic biomass, production, C-sequestration and thus ultimately the global carbon cycle and climate. © 2014 The Author. Published by Oxford University Press. All rights reserved.

  4. Top quark properties at ATLAS

    CERN Document Server

    Dilip, Jana

    2008-01-01

    The ATLAS potential for the study of the top quark properties and physics beyond the Standard Model in the top quark sector, is described. The measurements of the top quark charge, the spin and spin correlations, the Standard Model decay (t-> bW), rare top quark decays associated to flavour changing neutral currents (t-> qX with X = gluon, Z, photon) and ttbar resonances are discussed. The sensitivity of the ATLAS experiment is estimated for an expected luminosity of 1fb-1 at the LHC. The full simulation of the ATLAS detector is used. For the Standard Model measurements the expected precision is presented. For the tests of physics beyond the Standard Model, the 5 sigma discovery potential (in the presence of a signal) and the 95% Confidence Level (CL) limit (in the absence of a signal) are given.

  5. Võrumaa ettevõtete TOP 50 aastal 2003

    Index Scriptorium Estoniae

    2004-01-01

    Võrumaa ettevõtete TOP 50 aastal 2003. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Võrumaa firmade üld- ja finantsandmed

  6. Uncovering the single top: observation of electroweak top quark production

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Jorge Armando [Michigan State Univ., East Lansing, MI (United States)

    2009-01-01

    The top quark is generally produced in quark and anti-quark pairs. However, the Standard Model also predicts the production of only one top quark which is mediated by the electroweak interaction, known as 'Single Top'. Single Top quark production is important because it provides a unique and direct way to measure the CKM matrix element Vtb, and can be used to explore physics possibilities beyond the Standard Model predictions. This dissertation presents the results of the observation of Single Top using 2.3 fb-1 of Data collected with the D0 detector at the Fermilab Tevatron collider. The analysis includes the Single Top muon+jets and electron+jets final states and employs Boosted Decision Tress as a method to separate the signal from the background. The resulting Single Top cross section measurement is: (1) σ(p$\\bar{p}$→ tb + X, tqb + X) = 3.74-0.74+0.95 pb, where the errors include both statistical and systematic uncertainties. The probability to measure a cross section at this value or higher in the absence of signal is p = 1.9 x 10-6. This corresponds to a standard deviation Gaussian equivalence of 4.6. When combining this result with two other analysis methods, the resulting cross section measurement is: (2) σ(p$\\bar{p}$ → tb + X, tqb + X) = 3.94 ± 0.88 pb, and the corresponding measurement significance is 5.0 standard deviations.

  7. Search for Top in TOTEM

    CERN Document Server

    Corrales, Alonso

    2017-01-01

    The work assigned to me during this summer (from June 19th to August 11th) was in the "Search for Top in TOTEM" project, a CMG project in collaboration with TOTEM, under the supervision of Martijn Mulders and Laurent Forthomme. The goal is to determine physical properties of the top anti top quark pair (tt) created by central exclusive processes, particularly the invariant mass. For that it is necessary to relate the measurements of the reconstructed top pair kinematics in the central detector of CMS with the detected protons in the Roman Pots of TOTEM just outside the interaction site, about 200 m from it. CMS only considers decay products from the proton collision, it does not regard the forward protons that participated in the collision. On the contrary, TOTEM does consider these protons. In this research measurements of both TOTEM and CMS were combined Figure 1 shows a diagram of the production of the top anti top pair from the interaction of the two protons. A central exclusive process occurs when the pr...

  8. Active Marine Station Metadata

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Active Marine Station Metadata is a daily metadata report for active marine bouy and C-MAN (Coastal Marine Automated Network) platforms from the National Data...

  9. Marine Sciences

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    PNL research in the marine sciences is focused on establishing a basic understanding of the mechanisms of stress and tolerance in marine organisms exposed to contaminants. Several environmental stressors had been investigated in earlier energy-related research. In a landmark study, for example, PNL had established that the severity of fish disease caused by the common infectious agent, Flexobacter columnaris, was seriously aggravated by thermal enhancement and certain ecological factors. Subsequent studies demonstrated that the primary immune response in fish, challenged by columnaris, could be permanently suppressed by comparatively low tritium exposures. The research has suggested that a potential exists for a significant biological impact when an aquatic stressor is added to an ambient background of other stressors, which may include heat, heavy metal ions, radiation or infectious microorganisms. More recently, PNL investigators have shown that in response to heavy metal contaminants, animals synthesize specific proteins (metallothioneins), which bind and sequester metals in the animals, thus decreasing metal mobility and effects. Companion studies with host-specific intracellular pathogens are being used to investigate the effects of heavy metals on the synthesis of immune proteins, which mitigate disease processes. The results of these studies aid in predicting the ecological effects of energy-related contaminants on valued fin and shellfish species

  10. The theory of the top

    CERN Document Server

    Klein, Felix; Nagem, Raymond J; Sandri, Guido

    The Theory of the Top. Volume IV. Technical Applications of the Theory of the Top is the fourth and final volume in a series of self-contained English translations of the classic and definitive treatment of rigid body motion. Key features: * Complete and unabridged presentation with recent advances and additional notes; * Annotations by the translators provide insights into the nature of science and mathematics in the late 19th century; * Each volume interweaves theory and applications. The Theory of the Top was originally presented by Felix Klein as an 1895 lecture at Göttingen University that was broadened in scope and clarified as a result of collaboration with Arnold Sommerfeld.  Graduate students and researchers interested in theoretical and applied mechanics will find this series of books a thorough and insightful account.  Other volumes in the series include Introduction to the Kinematics and Kinetics of the Top, Development of the Theory in the Case of the Heavy Symmetric Top, and Perturbation...

  11. Kinematic top analyses at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Grassmann, H.; CDF Collaboration

    1995-03-01

    We present an update of the top quark analysis using kinematic techniques in p{bar p} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We reported before on a study which used 19.3 pb{sup {minus}1} of data from the 1992--1993 collider run, but now we use a larger data sample of 67 pb{sup {minus}1}. First, we analyze the total transverse energy of the hard collision in W+{ge}3 jet events, showing the likely presence of a t{bar t} component in the event sample. Next, we compare in more detail the kinematic structure of W+ {ge}3 jet events with expectations for top pair production and with background processes, predominantly direct W+ jet production. We again find W+ {ge} 3 jet events which cannot be explained in terms of background, but show kinematic features as expected from top. These events also show evidence for beauty quarks, in agreement with expectations from top, but not compatible with expectations from backgrounds. The findings confirm the observation of top events made earlier in the data of the 1992--1993 collider run.

  12. An intercomparison of methods for solving the stochastic collection equation with a focus on cloud radar Doppler spectra in drizzling stratocumulus

    Science.gov (United States)

    Lee, H.; Fridlind, A. M.; Ackerman, A. S.; Kollias, P.

    2017-12-01

    Cloud radar Doppler spectra provide rich information for evaluating the fidelity of particle size distributions from cloud models. The intrinsic simplifications of bulk microphysics schemes generally preclude the generation of plausible Doppler spectra, unlike bin microphysics schemes, which develop particle size distributions more organically at substantial computational expense. However, bin microphysics schemes face the difficulty of numerical diffusion leading to overly rapid large drop formation, particularly while solving the stochastic collection equation (SCE). Because such numerical diffusion can cause an even greater overestimation of radar reflectivity, an accurate method for solving the SCE is essential for bin microphysics schemes to accurately simulate Doppler spectra. While several methods have been proposed to solve the SCE, here we examine those of Berry and Reinhardt (1974, BR74), Jacobson et al. (1994, J94), and Bott (2000, B00). Using a simple box model to simulate drop size distribution evolution during precipitation formation with a realistic kernel, it is shown that each method yields a converged solution as the resolution of the drop size grid increases. However, the BR74 and B00 methods yield nearly identical size distributions in time, whereas the J94 method produces consistently larger drops throughout the simulation. In contrast to an earlier study, the performance of the B00 method is found to be satisfactory; it converges at relatively low resolution and long time steps, and its computational efficiency is the best among the three methods considered here. Finally, a series of idealized stratocumulus large-eddy simulations are performed using the J94 and B00 methods. The reflectivity size distributions and Doppler spectra obtained from the different SCE solution methods are presented and compared with observations.

  13. WordPress Top Plugins

    CERN Document Server

    Corbin, Brandon

    2010-01-01

    Time flies when you're having fun. This is the right way to describe this WordPress Top Plugins book by Brandon Corbin. With real world examples and by showing you the perks of having these plugins installed on your websites, the author is all set to captivate your interest from start to end. Regardless of whether this is your first time working with WordPress, or you're a seasoned WordPress coding ninja, WordPress Top Plugins will walk you through finding and installing the best plugins for generating and sharing content, building communities and reader base, and generating real advertising r

  14. Top-down cascades in lakes and oceans: Different perspectives but same story?

    KAUST Repository

    Hessen, Dag Olav; Kaartvedt, Stein

    2014-01-01

    While top-down cascades from fish to phytoplankton have been a core topic in limnology for the past four decades, it has attracted far less interest in marine ecology. This is partly for historical reasons, since lake studies have been motivated

  15. Climbing back to the top

    Energy Technology Data Exchange (ETDEWEB)

    Curry, Lynn

    2010-07-01

    California - the top wind producer in the US since the 1980s lost its lead in 2008 in the face of intense competition from other states. But backed by strong financial and political support from the government, California's wind energy sector is slowly making a comeback. (orig.)

  16. Kowalevski top in quantum mechanics

    International Nuclear Information System (INIS)

    Matsuyama, A.

    2013-01-01

    The quantum mechanical Kowalevski top is studied by the direct diagonalization of the Hamiltonian. The spectra show different behaviors depending on the region divided by the bifurcation sets of the classical invariant tori. Some of these spectra are nearly degenerate due to the multiplicity of the invariant tori. The Kowalevski top has several symmetries and symmetry quantum numbers can be assigned to the eigenstates. We have also carried out the semiclassical quantization of the Kowalevski top by the EBK formulation. It is found that the semiclassical spectra are close to the exact values, thus the eigenstates can be also labeled by the integer quantum numbers. The symmetries of the system are shown to have close relations with the semiclassical quantum numbers and the near-degeneracy of the spectra. -- Highlights: •Quantum spectra of the Kowalevski top are calculated. •Semiclassical quantization is carried out by the EBK formulation. •Quantum states are labeled by the semiclassical integer quantum numbers. •Multiplicity of the classical torus makes the spectra nearly degenerate. •Symmetries, quantum numbers and near-degenerate spectra are closely related

  17. Top production at hadron colliders

    Indian Academy of Sciences (India)

    mulated by the summer of 2010, the first top quark event candidates were observed and ..... Result of combined fit to data in the exclusive three-jet bin, the exclusive .... Figure 7 shows the results of a model-independent measurement of.

  18. TEMAC, Top Event Sensitivity Analysis

    International Nuclear Information System (INIS)

    Iman, R.L.; Shortencarier, M.J.

    1988-01-01

    1 - Description of program or function: TEMAC is designed to permit the user to easily estimate risk and to perform sensitivity and uncertainty analyses with a Boolean expression such as produced by the SETS computer program. SETS produces a mathematical representation of a fault tree used to model system unavailability. In the terminology of the TEMAC program, such a mathematical representation is referred to as a top event. The analysis of risk involves the estimation of the magnitude of risk, the sensitivity of risk estimates to base event probabilities and initiating event frequencies, and the quantification of the uncertainty in the risk estimates. 2 - Method of solution: Sensitivity and uncertainty analyses associated with top events involve mathematical operations on the corresponding Boolean expression for the top event, as well as repeated evaluations of the top event in a Monte Carlo fashion. TEMAC employs a general matrix approach which provides a convenient general form for Boolean expressions, is computationally efficient, and allows large problems to be analyzed. 3 - Restrictions on the complexity of the problem - Maxima of: 4000 cut sets, 500 events, 500 values in a Monte Carlo sample, 16 characters in an event name. These restrictions are implemented through the FORTRAN 77 PARAMATER statement

  19. Top mass measurement at CDF

    International Nuclear Information System (INIS)

    Rolli, S.

    1996-06-01

    We present the measurement of the top quark mass using L = 110 pb -1 data sample of pp collisions at √s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). We show the results for the different channels and discuss with some emphasis the determination of the systematic uncertainties. 7 refs., 10 figs., 5 tabs

  20. Observation of the Top Quark

    Science.gov (United States)

    Kim, S. B.

    1995-08-01

    Top quark production is observed in{bar p}p collisions at{radical}s= 1.8 TeV at the Fermilab Tevatron. The Collider Detector at Fermilab (CDF) and D{O} observe signals consistent with t{bar t} to WWb{bar b}, but inconsistent with the background prediction by 4.8{sigma} (CDF), 4.6a (D{O}). Additional evidence for the top quark Is provided by a peak in the reconstructed mass distribution. The kinematic properties of the excess events are consistent with the top quark decay. They measure the top quark mass to be 176{plus_minus}8(stat.){plus_minus}10(sys.) GeV/c{sup 2} (CDF), 199{sub -21}{sup+19}(stat.){plus_minus}22(sys.) GeV/c{sup 2} (D{O}), and the t{bar t} production cross section to be 6.8{sub -2.4}{sup+3.6}pb (CDF), 6.4{plus_minus}2.2 pb (D{O}).

  1. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.

    2013-01-01

    We introduce a new compression scheme for labeled trees based on top trees [3]. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  2. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.

    2015-01-01

    We introduce a new compression scheme for labeled trees based on top trees. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  3. Top Jets at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, L.G.; Lee, S.J.; Perez, G.; Sung, I.; Virzi, J.

    2008-10-06

    We investigatethe reconstruction of high pT hadronically-decaying top quarksat the Large Hadron Collider. One of the main challenges in identifying energetictop quarks is that the decay products become increasingly collimated. This reducesthe efficacy of conventional reconstruction methods that exploit the topology of thetop quark decay chain. We focus on the cases where the decay products of the topquark are reconstructed as a single jet, a"top-jet." The most basic"top-tag" methodbased on jet mass measurement is considered in detail. To analyze the feasibility ofthe top-tagging method, both theoretical and experimental aspects of the large QCDjet background contribution are examined. Based on a factorization approach, wederive a simple analytic approximation for the shape of the QCD jet mass spectrum.We observe very good agreement with the Monte Carlo simulation. We consider high pT tt bar production in the Standard Model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with 25 fb-1 of data, our approach allows us to resolve top-jets with pT _> 1 TeV, from the QCD background, and about 1.5 TeV top-jets with 100 fb-1, without relying on b-tagging. To further improve the significancewe consider jet shapes (recently analyzed in 0807.0234 [hep-ph]), which resolve thesubstructure of energy flow inside cone jets. A method of measuring the top quarkpolarization by using the transverse momentum of the bottom quark is also presented.The main advantages of our approach are: (i) the mass distributions are driven byfirst principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high pT jets (pT _> 1 TeV), IR-safe jet shape variables are robust against detectorresolution effects. Our analysis can be applied to other boosted massive particlessuch as the electroweak gauge bosons and the Higgs.

  4. Measurements of Top Properties at the Tevatron

    International Nuclear Information System (INIS)

    Husemann, Ulrich; Yale U.

    2007-01-01

    The large data samples of thousands of top events collected at the Tevatron experiments CDF and D(O) allow for a variety of measurements to analyze the properties of the top quark. Guided by the question ''Is the top quark observed at the Tevatron really the top quark of the standard model,'' we present Tevatron analyses studying the top production mechanism including resonant t(bar t) production, the V -A structure of the t → Wb decay vertex, the charge of the top quark, and single-top production via flavor-changing neutral currents

  5. Properties of the Top Quark

    Energy Technology Data Exchange (ETDEWEB)

    Wicke, Daniel; /Wuppertal U., Dept. Math.

    2009-08-01

    The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the

  6. Properties of the Top Quark

    International Nuclear Information System (INIS)

    Wicke, Daniel

    2009-01-01

    The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the

  7. Toiduainetööstuse TOP 95 aastal 2003

    Index Scriptorium Estoniae

    2004-01-01

    Toiduainetööstuse TOP 95; Kasumi TOP 40; Käibe TOP 40; Kasumi kasvu TOP 30; Rentaabluse TOP 30; Alkoholitootjate TOP; Pagarite TOP; Käibe kasvu TOP 30; Omakapitali tootlikkuse TOP 30; Toiduainetööstuste üld- ja finantsandmed

  8. Top quark production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Varnes, Erich W.; /Arizona U.

    2010-09-01

    The Fermilab Tevatron has, until recently, been the only accelerator with sufficient energy to produce top quarks. The CDF and D0 experiments have collected large samples of top quarks. We report on recent top quark production measurements of the single top and t{bar t} production cross sections, as well as studies of the t{bar t} invariant mass distribution and a search for highly boosted top quarks.

  9. Drivers of Seasonal Variability in Marine Boundary Layer Aerosol Number Concentration Investigated Using a Steady State Approach

    Science.gov (United States)

    Mohrmann, Johannes; Wood, Robert; McGibbon, Jeremy; Eastman, Ryan; Luke, Edward

    2018-01-01

    Marine boundary layer (MBL) aerosol particles affect the climate through their interaction with MBL clouds. Although both MBL clouds and aerosol particles have pronounced seasonal cycles, the factors controlling seasonal variability of MBL aerosol particle concentration are not well constrained. In this paper an aerosol budget is constructed representing the effects of wet deposition, free-tropospheric entrainment, primary surface sources, and advection on the MBL accumulation mode aerosol number concentration (Na). These terms are then parameterized, and by assuming that on seasonal time scales Na is in steady state, the budget equation is rearranged to form a diagnostic equation for Na based on observable variables. Using data primarily collected in the subtropical northeast Pacific during the MAGIC campaign (Marine ARM (Atmospheric Radiation Measurement) GPCI (GCSS Pacific Cross-Section Intercomparison) Investigation of Clouds), estimates of both mean summer and winter Na concentrations are made using the simplified steady state model and seasonal mean observed variables. These are found to match well with the observed Na. To attribute the modeled difference between summer and winter aerosol concentrations to individual observed variables (e.g., precipitation rate and free-tropospheric aerosol number concentration), a local sensitivity analysis is combined with the seasonal difference in observed variables. This analysis shows that despite wintertime precipitation frequency being lower than summer, the higher winter precipitation rate accounted for approximately 60% of the modeled seasonal difference in Na, which emphasizes the importance of marine stratocumulus precipitation in determining MBL aerosol concentrations on longer time scales.

  10. Thermal design of top shield

    International Nuclear Information System (INIS)

    Raghupathy, S.; Velusamy, K.; Parthasarathy, U.; Ghosh, D.; Selvaraj, P.; Chellapandi, P.; Chetal, S.C.

    2005-01-01

    Full text of publication follows: Prototype Fast Breeder Reactor (PFBR) is a 500 MWe, sodium cooled, pool type fast reactor. The top shield forms the top cover for the main vessel (MV) and includes roof slab (RS), large rotatable plug (LRP), small rotatable plug (SRP) and control Plug (CP). RS, LRP and SRP are box type structures consisting of top and bottom plates stiffened by radial stiffeners and vertical penetration shells. TS is exposed to argon cover gas provided above sodium pool on the bottom side and reactor containment building air at the top. Heat transfer takes place through the argon cover gas to the bottom plate of TS. Annular gaps are formed between the components supported on TS and the component penetrations through which cellular convection takes place. A single thermal shield provided below TS reduces the heat flux to the bottom plate to 1.15 kW/m 2 . The MV (SS 316 LN) is welded to RS (carbon steel A48 P2) through a dissimilar metal weld. A step in RS and an anti convection barrier (ACB) outside RS are provided to limit the temperature at the MV-RS junction. The MV is surrounded by safety vessel (SV) and reactor vault made of concrete. Thermal insulation is provided outside SV to limit the heat transfer to the reactor vault. The design requirements of TS are to maintain the operating temperature at 383-393 K, limit the temperature difference (ΔT) across the height of TS to 20 / 100 K under normal operation/loss of cooling, provide minimum annular gap size at the component penetrations, provide a nearly linear temperature gradient in the CP portion within the height of TS, maintain the temperature of top plate of CP > 383 K, limit the ΔT across the top plate of CP to 2 K, limit the temperature near the inflatable / backup seal to 393 K, limit the temperature at the MV-RS junction and the heat flux to the reactor vault. The total heat transferred to TS is estimated to be 210 kW. A dedicated closed loop cooling system with a total flow rate of 10

  11. On the Nature and Extent of Optically Thin Marine low Clouds

    Science.gov (United States)

    Leahy, L. V.; Wood, R.; Charlson, R. J.; Hostetler, C. A.; Rogers, R. R.; Vaughan, M. A.; Winker, D. M.

    2012-01-01

    Macrophysical properties of optically thin marine low clouds over the nonpolar oceans (60 deg S-60 deg N) are measured using 2 years of full-resolution nighttime data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Optically thin clouds, defined as the subset of marine low clouds that do not fully attenuate the lidar signal, comprise almost half of the low clouds over the marine domain. Regionally, the fraction of low clouds that are optically thin (f(sub thin,cld)) exhibits a strong inverse relationship with the low-cloud cover, with maxima in the tropical trades (f(sub thin,cld) greater than 0.8) and minima in regions of persistent marine stratocumulus and in midlatitudes (f(sub thin,cld) less than 0.3). Domain-wide, a power law fit describes the cloud length distribution, with exponent beta = 2.03 +/- 0.06 (+/-95% confidence interval). On average, the fraction of a cloud that is optically thin decreases from approximately 1 for clouds smaller than 2 km to less than 0.3 for clouds larger than 30 km. This relationship is found to be independent of region, so that geographical variations in the cloud length distribution explain three quarters of the variance in f(sub thin,cld). Comparing collocated trade cumulus observations from CALIOP and the airborne High Spectral Resolution Lidar reveals that clouds with lengths smaller than are resolvable with CALIOP contribute approximately half of the low clouds in the region sampled. A bounded cascade model is constructed to match the observations from the trades. The model shows that the observed optically thin cloud behavior is consistent with a power law scaling of cloud optical depth and suggests that most optically thin clouds only partially fill the CALIOP footprint.

  12. Marine animal stings or bites

    Science.gov (United States)

    Stings - marine animals; Bites - marine animals ... Things you can do to prevent a marine animal sting or bite include: Swim near a lifeguard. Observe posted signs that may warn of danger from jellyfish or other hazardous marine life. ...

  13. Top quark studies at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)

    1997-01-01

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.

  14. Top quark studies at hadron colliders

    International Nuclear Information System (INIS)

    Sinervo, P.K.

    1997-01-01

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented

  15. Top quark studies at hadron colliders

    International Nuclear Information System (INIS)

    Sinervo, P.K.

    1996-08-01

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and D null collaborations are reviewed, including the top quark cross section, mass, branching fractions and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented

  16. Mariners Weather Log

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Mariners Weather Log (MWL) is a publication containing articles, news and information about marine weather events and phenomena, worldwide environmental impact...

  17. MarineCadastre.gov

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MarineCadastre.gov is a marine information system that provides authoritative ocean data, offshore planning tools, and technical support to the offshore renewable...

  18. Marine Jurisdiction Boundaries

    Data.gov (United States)

    Department of Homeland Security — The NOAA Coastal Services Center's Marine Jurisdiction dataset was created to assist in marine spatial planning and offshore alternative energy sitting. This is a...

  19. Tsunamis and marine life

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.V.S.; Ingole, B.S.; Tang, D.; Satyanarayan, B.; Zhao, H.

    The 26 December 2004 tsunami in the Indian Ocean exerted far reaching temporal and spatial impacts on marine biota. Our synthesis was based on satellite data acquired by the Laboratory for Tropical Marine Environmental Dynamics (LED) of the South...

  20. Supermarket Marine Biology.

    Science.gov (United States)

    Colby, Jennifer A.; And Others

    1995-01-01

    Describes a survey used to determine the availability of intact marine vertebrates and live invertebrates in supermarkets. Results shows that local supermarkets frequently provide a variety of intact marine organisms suitable for demonstrations, experiments, or dissections. (ZWH)

  1. Seashore marine table quiz

    OpenAIRE

    Institute, Marine

    2013-01-01

    Develop an increasing awareness of plants and animals that live in local marine environments including the seashore, seas and oceans of Ireland. After learning all about the seashore and other marine related lessons, this quiz can be used to evaluate the student’s knowledge of the marine related living things and natural environments. The table quiz can be used as a guide, highlighting facts about the marine environment and some of the animals that live there.

  2. Carotenoids in Marine Animals

    OpenAIRE

    Maoka, Takashi

    2011-01-01

    Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine a...

  3. Toiduainetööstuse TOP 95 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Toiduainetööstuse TOP 95. Käibe TOP 50. Kasumi TOP 50. Rentaabluse TOP 25. Kasumi kasvu TOP 25. Omakapitali tootlikkuse TOP 25. Käibe kasvu TOP 25. Toiduainetööstuse TOP 95 ettevõtted 2002: üldandmed ja finantsandmed

  4. Ida-Virumaa ettevõtete TOP aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Ettevõtete TOP 55. TOP-i esikümme. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Ida-Virumaa firmade üldandmed. Ida-Virumaa firmade finantsandmed

  5. Marine Education Knowledge Inventory.

    Science.gov (United States)

    Hounshell, Paul B.; Hampton, Carolyn

    This 35-item, multiple-choice Marine Education Knowledge Inventory was developed for use in upper elementary/middle schools to measure a student's knowledge of marine science. Content of test items is drawn from oceanography, ecology, earth science, navigation, and the biological sciences (focusing on marine animals). Steps in the construction of…

  6. Marine polar steroids

    International Nuclear Information System (INIS)

    Stonik, Valentin A

    2001-01-01

    Structures, taxonomic distribution and biological activities of polar steroids isolated from various marine organisms over the last 8-10 years are considered. The peculiarities of steroid biogenesis in the marine biota and their possible biological functions are discussed. Syntheses of some highly active marine polar steroids are described. The bibliography includes 254 references.

  7. Table-top job analysis

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-01

    The purpose of this Handbook is to establish general training program guidelines for training personnel in developing training for operation, maintenance, and technical support personnel at Department of Energy (DOE) nuclear facilities. TTJA is not the only method of job analysis; however, when conducted properly TTJA can be cost effective, efficient, and self-validating, and represents an effective method of defining job requirements. The table-top job analysis is suggested in the DOE Training Accreditation Program manuals as an acceptable alternative to traditional methods of analyzing job requirements. DOE 5480-20A strongly endorses and recommends it as the preferred method for analyzing jobs for positions addressed by the Order.

  8. Top-down cellular pyramids

    Energy Technology Data Exchange (ETDEWEB)

    Wu, A Y; Rosenfeld, A

    1983-10-01

    A cellular pyramid is an exponentially tapering stack of arrays of processors (cells), where each cell is connected to its neighbors (siblings) on its own level, to a parent on the level above, and to its children on the level below. It is shown that in some situations, if information flows top-down only, from fathers to sons, then a cellular pyramid may be no faster than a one-level cellular array; but it may be possible to use simpler cells in the pyramid case. 23 references.

  9. As multiple fish species in large marine ecosystems are harvested ...

    African Journals Online (AJOL)

    CMPTMAC10

    and of other top predators such as marine mammals. This concern ... whereas single-species fishing theory implies that fishing leads to surplus by removing larger, older, less-productive ...... pools (the “cod is not a tuna” problem, Longhurst.

  10. Top quark production at the LHC

    CERN Document Server

    Gilles, Geoffrey; The ATLAS collaboration

    2018-01-01

    The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, it gives us the unique opportunity to probe the properties of bare quarks at the Large Hadron Collider. This talk will present highlights of a few recent precision measurements of the top quark using 13 TeV and 8 TeV collision data: top-quark pair and single top production cross sections, including differential distributions and production in association with bosons, will be presented alongside top quark properties measurements. These measurements, including results using boosted top quarks, probe our understanding of top quark production in the TeV regime. Measurements of the top quark mass are also presented.

  11. Results on top-quark physics and top-quark-like signatures by CMS

    Science.gov (United States)

    Chabert, Eric; CMS Collaboration

    2017-07-01

    This report reviews the results obtained by the CMS Collaboration on top quark physics, focusing on the latest ones based on p-p collisions provided by the LHC at \\sqrt{s}=13{{TeV}} during Run II. It covers measurements of single-top, top quark pairs and associated productions as well as measurements of top quark properties. Finally several beyond the standard model searches involving top quark in the final states are presented, such as searches for supersymmetry in the third generation, heavy resonances decaying into a top quark pair, or dark matter produced in association to a single-top or a top quark pair.

  12. Top mass in ATLAS and CMS

    CERN Document Server

    Castro, A.

    2017-01-01

    Top quarks are produced copiously at the LHC, and a variety of related measurements has been made in the recent years by the two collaborations ATLAS and CMS. The most recent measurements of the top quark mass by the two collaborations are reported here. The top quark mass has been measured with a relative uncertainty smaller than 0.3pct, making the top quark the most accurately measured quark.

  13. New Physics in Single-Top Production

    CERN Document Server

    Kind, OM; The ATLAS collaboration

    2013-01-01

    In this presentation for TOP 2013 the latest results on searches of physics beyond the Standard Model using single-top signatures from CDF, CMS, D0 and ATLAS are collected. This includes searches for unknown resonances like W' or b*, measurements of the W helicity fractions and top polarisation in single-top events, as well as tests for CP violation, FCNC or anomalous weak couplings.

  14. MHD Integrated Topping Cycle Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

  15. Marine nitrogen cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    ) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

  16. Carotenoids in Marine Animals

    Science.gov (United States)

    Maoka, Takashi

    2011-01-01

    Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine animal carotenoids from natural product chemistry, metabolism, food chain, and chemosystematic viewpoints, and also describe new structural carotenoids isolated from marine animals over the last decade. PMID:21566799

  17. Marine Robot Autonomy

    CERN Document Server

    2013-01-01

    Autonomy for Marine Robots provides a timely and insightful overview of intelligent autonomy in marine robots. A brief history of this emerging field is provided, along with a discussion of the challenges unique to the underwater environment and their impact on the level of intelligent autonomy required.  Topics covered at length examine advanced frameworks, path-planning, fault tolerance, machine learning, and cooperation as relevant to marine robots that need intelligent autonomy.  This book also: Discusses and offers solutions for the unique challenges presented by more complex missions and the dynamic underwater environment when operating autonomous marine robots Includes case studies that demonstrate intelligent autonomy in marine robots to perform underwater simultaneous localization and mapping  Autonomy for Marine Robots is an ideal book for researchers and engineers interested in the field of marine robots.      

  18. Search for Single Top Production at LEP

    CERN Document Server

    Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Echenard, B; Eline, A; El-Mamouni, H; Engler, A; Eppling, F J; Ewers, A; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hakobyan, R S; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krenz, W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S A; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Lübelsmeyer, K; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nisati, A; Nowak, H; Ofierzynski, R A; Organtini, G; Palomares, C; Pandoulas, D; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofiev, D O; Prokofev, D; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Roux, B; Rubio, Juan Antonio; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Sanders, M P; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schopper, Herwig Franz; Schotanus, D J; Schwering, G; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S V; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R P; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wallraff, W; Wang, X L; Wang, Z M; Weber, M; Wienemann, P; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M

    2002-01-01

    Single top production in e^+e^- annihilations is searched for in data collected by the L3 detector at centre-of-mass energies from 189 to 209 GeV, corresponding to a total integrated luminosity of 634 pb-1. Investigating hadronic and semileptonic top decays, no evidence of single top production at LEP is obtained and upper limits on the single top cross section as a function of the centre-of-mass energy are derived. Limits on possible anomalous couplings, as well as on the scale of contact interactions responsible for single top production are determined.

  19. Single top quark production with CMS

    Directory of Open Access Journals (Sweden)

    Piccolo Davide

    2013-11-01

    Full Text Available Measurements of single top quark production performed using the CMS experiment [1] data collected in 2011 at centre-of-mass energies of 7 TeV and in 2012 at 8 TeV, are presented. The cross sections for the electroweak production of single top quarks in the t-channel and in association with W-bosons is measured and the results are used to place constraints on the CKM matrix element Vtb. Measurements of top quark properties in single top quark production are also presented. The results include the measurement of the charge ratio in the single top t-channel.

  20. CP Violation in Single Top Quark Production

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Weigang [Michigan State Univ., East Lansing, MI (United States)

    2012-01-01

    We present a search for CP violation in single top quark production with the DØ experiment at the Tevatron proton-antiproton collider. CP violation in the top electroweak interaction results in different single top quark production cross sections for top and antitop quarks. We perform the search in the single top quark final state using 5.4 fb-1 of data, in the s-channel, t-channel, and for both combined. At this time, we do not see an observable CP asymmetry.

  1. Top quark physics at the LHC

    Directory of Open Access Journals (Sweden)

    Jeong Kim Tae

    2014-04-01

    Full Text Available In 2011, an integrated luminosity of more than 5 fb−1 at 7 TeV has been delivered by the LHC. The measurement of the cross section in top quark pair production and in single top quark production, top quark mass, top quark properties and new physics searches in top quark decays have been performed at the CMS experiment with various integrated luminosities. An overview of the latest results of these measurements and searches by the time of ICFP 2012 conference will be presented.

  2. Top flooding modeling with MAAP4 code

    International Nuclear Information System (INIS)

    Brunet-Thibault, E.; Marguet, S.

    2006-01-01

    An engineering top flooding model was developed in MAAP4.04d.4, the severe accident code used in EDF, to simulate the thermal-hydraulic phenomena that should take place if emergency core cooling (ECC) water was injected in hot leg during quenching. In the framework of the ISTC (International Science and Technology Centre), a top flooding test was proposed in the PARAMETER facility (Podolsk, Russia). The MAAP calculation of the PARAMETER top flooding test is presented in this paper. A comparison between top and bottom flooding was made on the bundle test geometry. According to this study, top flooding appears to cool quickly and effectively the upper plenum internals. (author)

  3. Searching for the top at UA2

    International Nuclear Information System (INIS)

    Unal, G.

    1990-10-01

    The projects conceived for searching the quark top, predicted by the Standard Model, are described. The required existence of the quark top from the Standard Model and its production from proton-antiproton collisions are reviewed. The UA2 experimental device is described. The method applied for the search of the top is explained. The analysis of the UA2 data does not allow to conclude the existence of the top. However, the low mass limit of 69 GeV/C 2 can be established for the top mass. The results of the analysis of the W decays into supersymmetric particles are included [fr

  4. Top down electroweak dipole operators

    Science.gov (United States)

    Fuyuto, Kaori; Ramsey-Musolf, Michael

    2018-06-01

    We derive present constraints on, and prospective sensitivity to, the electric dipole moment (EDM) of the top quark (dt) implied by searches for the EDMs of the electron and nucleons. Above the electroweak scale v, the dt arises from two gauge invariant operators generated at a scale Λ ≫ v that also mix with the light fermion EDMs under renormalization group evolution at two-loop order. Bounds on the EDMs of first generation fermion systems thus imply bounds on |dt |. Working in the leading log-squared approximation, we find that the present upper bound on |dt | is 10-19 e cm for Λ = 1 TeV, except in regions of finely tuned cancellations that allow for |dt | to be up to fifty times larger. Future de and dn probes may yield an order of magnitude increase in dt sensitivity, while inclusion of a prospective proton EDM search may lead to an additional increase in reach.

  5. Top Management Involvement in New Product Development

    DEFF Research Database (Denmark)

    Felekoglu, Burcu; Maier, Anja; Moultrie, James

    2010-01-01

    a broader conceptual space than this participation. This paper reviews the literature on top management involvement in new product development (NPD) and discusses relevance of different theoretical perspectives from other disciplines such as management, organisational behaviour and communication to analyse......Involvement of top managers in new product development (NPD) is a critical factor affecting NPD performance and frequently considered to be the participation of top management to certain activities in NPD or their NPD related behaviours. However, “Top management involvement in NPD” occupies...... antecedents, realisation and consequences of top management involvement in NPD. It is argued that top management has different involvement at different NPD levels: organisation level and project level. Resulting from this literature review, a tentative framework for top management involvement in NPD...

  6. Ravimimüüjate TOP 30 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Ravimimüüjate TOP 30 aastal 2002. Käibe TOP 30. Kasumi TOP 30. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Ravimimüüjad 2002: üld- ja finantsandmed

  7. Tekstiilitööstuse TOP 30 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Tekstiilitööstuse TOP 30. Kasumi TOP 30. Käibe TOP 30. Rentaabluse TOP 20. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Omakapitali tootlikkuse TOP 20. Tekstiilitööstuse ettevõtted 2002: üld- ja finantsandmed

  8. Trükitööstuste TOP 50

    Index Scriptorium Estoniae

    2002-01-01

    Trükitööstuste TOP 50. Käibe TOP 30. Käibe kasum TOP 30. Kasvu TOP 30. Kasumi kasvu TOP 30. Rentaabluse TOP. Varade tootlikkuse TOP. Trükitööstusettevõtete üldandmed. Trükitööstusettevõtete finantsandmed

  9. Rõivatööstuse TOP 40 aastal 2002

    Index Scriptorium Estoniae

    2003-01-01

    Rõivatööstuse TOP 40. Käibe TOP 40. Kasumi TOP 40. Käibe kasvu TOP 20. Kasumi kasvu TOP 20. Rentaabluse TOP 20. Omakapitali tootlikkuse TOP 20. Rõivatööstuse ettevõtted: üldandmed ja finantsandmed

  10. Läänemaa ettevõtete TOP 50

    Index Scriptorium Estoniae

    2005-01-01

    Läänemaa ettevõtete TOP 50; Käibe TOP 35; Kasumi TOP 35; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20; Läänemaa ettevõtete üld- ja finantsandmed

  11. Ida-Virumaa ettevõtete TOP 50

    Index Scriptorium Estoniae

    2005-01-01

    Ilmunud ka: Delovõje Vedomosti-Severo-Vostok 7. sept. lk. 4. Ida-Virumaa ettevõtete TOP 50; Käibe TOP 35; Kasumi TOP 35; Käibe kasvu TOP 20; Kasumi kasvu TOP 20; Rentaabluse TOP 20; Omakapitali tootlikkuse TOP 20; Ida-Virumaa ettevõtete üld- ja finantsandmed

  12. Toiduainetööstuse TOP 100 aastal 2001

    Index Scriptorium Estoniae

    2002-01-01

    TOP 100. Toiduainetööstuste rentaabluse TOP 40. Varade tootlikkuse TOP 40. Käibe TOP 50. Käibe kasvu TOP 50. Kasumi TOP 50. Kasumi kasvu TOP 50. Toiduainetööstuse finantsandmed aastal 2001. Toiduainetööstuse üldandmed aastal 2001

  13. Lääne-Virumaa TOP 100 aastal 2000

    Index Scriptorium Estoniae

    2001-01-01

    Lääne-Virumaa edukamad ettevõtted; Lääne-Virumaa käibe TOP 100; Käibe kasvu TOP 20; Käibe languse TOP 10; Kasumi TOP 20; Kasumi kasvu TOP 20; Rentabluse TOP 20; ROA TOP 20; Kasumi languse TOP 10; Kahjumi TOP 10; Lääne-Virumaa käibelt suuremate ettevõtete finantsandmed. Lääne-Virumaa ettevõtete üldandmed

  14. Marine Environmental History

    DEFF Research Database (Denmark)

    Poulsen, Bo

    2012-01-01

    human society and natural marine resources. Within this broad topic, several trends and objectives are discernable. The essay argue that the so-called material marine environmental history has its main focus on trying to reconstruct the presence, development and environmental impact of past fisheries......This essay provides an overview of recent trends in the historiography of marine environmental history, a sub-field of environmental history which has grown tremendously in scope and size over the last c. 15 years. The object of marine environmental history is the changing relationship between...... and whaling operations. This ambition often entails a reconstruction also of how marine life has changed over time. The time frame rages from Paleolithicum to the present era. The field of marine environmental history also includes a more culturally oriented environmental history, which mainly has come...

  15. Marine electrical practice

    CERN Document Server

    Watson, G O

    1991-01-01

    Marine Engineering Series: Marine Electrical Practice, Sixth Edition focuses on changes in the marine industry, including the application of programmable electronic systems, generators, and motors. The publication first ponders on insulation and temperature ratings of equipment, protection and discrimination, and AC generators. Discussions focus on construction, shaft-drive generators, effect of unbalanced loading, subtransient and transient reactance, protection discrimination, fault current, measurement of ambient air temperature, and basis of machine ratings. The text then examines AC switc

  16. Biosurfactants from marine microorganisms

    Directory of Open Access Journals (Sweden)

    Suppasil Maneerat

    2005-11-01

    Full Text Available Biosurfactants are the surface-active molecules synthesized by microorganisms. With the advantage of environmental compatibility, the demand for biosurfactants has been steadily increasing and may eventually replace their chemically synthesized counterparts. Marine biosurfactants produced by some marine microorganisms have been paid more attention, particularly for the bioremediation of the sea polluted by crude oil. This review describes screening of biosurfactant-producing microorganisms, the determination of biosurfactant activity as well as the recovery of marine surfactant. The uses of marine biosurfactants for bioremediation are also discussed.

  17. Characterizing Marine Soundscapes.

    Science.gov (United States)

    Erbe, Christine; McCauley, Robert; Gavrilov, Alexander

    2016-01-01

    The study of marine soundscapes is becoming widespread and the amount of data collected is increasing rapidly. Data owners (typically academia, industry, government, and defense) are negotiating data sharing and generating potential for data syntheses, comparative studies, analyses of trends, and large-scale and long-term acoustic ecology research. A problem is the lack of standards and commonly agreed protocols for the recording of marine soundscapes, data analysis, and reporting that make a synthesis and comparison of results difficult. We provide a brief overview of the components in a marine soundscape, the hard- and software tools for recording and analyzing marine soundscapes, and common reporting formats.

  18. Top-of-Rail lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.

    2000-07-14

    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  19. Top medical news stories 2015

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2015-12-01

    Full Text Available No abstract available. Article truncated after 150 words. Here is our list of the top seven medical news stories for 2015 with special emphasis on the Southwest. 7. Wearable health devices: A wave of wearable computing devices such as Fitbit and UP wristbands have people keeping track of how much they sit, stand, walk, climb stairs and calories they consume (1. These fitness-tracking devices herald a series of devices that will detect and monitor serious diseases. However, these so-called medical-grade wearables require approval from the U.S. Food and Drug Administration, a regulatory hurdle avoided by the fitness-tracking devices which will likely slow their introduction. 6. Caitlyn Jenner: Caitlyn Jenner became the most famous transgender woman in the world following an interview published in Vanity Fair (2. The Vanity Fair website saw 11.6 million visits curious about the former Olympic athlete. Though Jenner publicly shared her gender identity, many transgender Americans do not-12% of gender non-conforming adults said they ...

  20. Measurement of top properties in ATLAS

    CERN Document Server

    Veloso, F; The ATLAS collaboration

    2010-01-01

    The top quark may play a special role in the Standard Model of particle physics. It is, for instance, the heaviest fundamental particle known, with a mass close to the electroweak symmetry breaking scale. Millions of top quark pairs will be produced per year at the LHC at nominal luminosity. ATLAS will measure many of the top quark properties with unprecedented precision. The ATLAS sensitivity studies done with Monte Carlo for the measurements of the top quark mass, the top quark charge, rare top quark decays and flavour changing neutral currents, the $t\\bar t$ spin correlations and $W$ boson polarization, the anomalous couplings at the $Wtb$ vertex and $t\\bar t$ resonances are reviewed.

  1. Qinshan CANDU project open top construction method

    International Nuclear Information System (INIS)

    Petrunik, K.J.; Wittann, K.; Khan, A.; Ricciuti, R.; Ivanov, A.; Chen, S.

    2003-01-01

    The significant schedule reductions achieved on the Qinshan CANDU Project were due in large part to the incorporation of advanced construction technologies in project design and delivery. For the Qinshan Project, a number of key advantages were realized through the use of the 'Open Top' construction method. This paper discusses the Qinshan Phase III CANDU Project Open Top implementation method. The Open Top method allowed major equipment to be installed simply, via the use of a Very Heavy Lift (VHL) crane and permitted the use of large-scale modularization. The advantages of Open Top construction, such as simplified access, more flexible project scheduling, improved construction safety and quality, and reduced labours are presented. The large-scale modularization of the Reactor Building Dousing System and the Open Top installation method and advantages relative to traditional CANDU 6 construction practices are also presented. Finally, major improvements for future CANDU plant construction using the Open Top method are discussed. (author)

  2. The significance of the heavy top quark

    International Nuclear Information System (INIS)

    Simmons, Elizabeth H.

    1997-01-01

    Experiment shows that the top quark is far heavier than the other elementary fermions. This finding has stimulated research on theories of electroweak and flavor symmetry breaking that include physics beyond the standard model. Efforts to accommodate a heavy top quark within existing frameworks have revealed constraints on model-building. Other investigations have started from the premise that a large top quark mass could signal a qualitative difference between the top quark and other fermions, perhaps in the form of new interactions peculiar to the top quark. Such new dynamics may also help answer existing questions about electroweak and flavor physics. This talk explores the implications of the heavy top quark in the context of weakly-coupled (e.g., SUSY) and strongly-coupled (e.g., technicolor) theories of electroweak symmetry breaking

  3. Top quark mass measurements with CMS

    CERN Document Server

    Kovalchuk, Nataliia

    2017-01-01

    Measurements of the top quark mass are presented, obtained from CMS data collected in proton-proton collisions at the LHC at centre-of-mass energies of 7 TeV and 8 TeV. The mass of the top quark is measured using several methods and channels, including the reconstructed invariant mass distribution of the top quark, an analysis of endpoint spectra as well as measurements from shapes of top quark decay distributions. The dependence of the mass measurement on the kinematic phase space is investigated. The results of the various channels are combined and compared to the world average. The top mass and also $\\alpha_{\\textnormal S}$ are extracted from the top pair cross section measured at CMS.

  4. Lunge feeding in early marine reptiles and fast evolution of marine tetrapod feeding guilds.

    Science.gov (United States)

    Motani, Ryosuke; Chen, Xiao-hong; Jiang, Da-yong; Cheng, Long; Tintori, Andrea; Rieppel, Olivier

    2015-03-10

    Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus reveals a well-preserved palate and mandible, which suggest that it was a rare lunge feeder as also occurs in rorqual whales and pelicans. The diversity of feeding strategies among Triassic marine tetrapods reached their peak in the Early Triassic, soon after their first appearance in the fossil record. The diet of these early marine tetrapods most likely included soft-bodied animals that are not preserved as fossils. Early marine tetrapods most likely introduced a new trophic mechanism to redistribute nutrients to the top 10 m of the sea, where the primary productivity is highest. Therefore, a simple recovery to a Permian-like trophic structure does not explain the biotic changes seen after the Early Triassic.

  5. TOP500 Supercomputers for November 2004

    Energy Technology Data Exchange (ETDEWEB)

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2004-11-08

    24th Edition of TOP500 List of World's Fastest Supercomputers Released: DOE/IBM BlueGene/L and NASA/SGI's Columbia gain Top Positions MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 24th edition of the TOP500 list of the worlds fastest supercomputers was released today (November 8, 2004) at the SC2004 Conference in Pittsburgh, Pa.

  6. TOP500 Supercomputers for June 2004

    Energy Technology Data Exchange (ETDEWEB)

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2004-06-23

    23rd Edition of TOP500 List of World's Fastest Supercomputers Released: Japan's Earth Simulator Enters Third Year in Top Position MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 23rd edition of the TOP500 list of the world's fastest supercomputers was released today (June 23, 2004) at the International Supercomputer Conference in Heidelberg, Germany.

  7. Top Quark Production at Hadron Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Phaf, Lukas Kaj [Univ. of Amsterdam (Netherlands)

    2004-03-01

    This thesis describes both theoretical and experimental research into top quark production. The theoretical part contains a calculation of the single-top quark production cross section at hadron colliders, at Next to Leading Order (NLO) accuracy. The experimental part describes a measurement of the top quark pair production cross section in proton-antiproton collisions, at a center of mass energy of 1.96 TeV.

  8. A table top exercise and workshop

    International Nuclear Information System (INIS)

    Lakey, J.R.A.

    1992-01-01

    Table top exercises are widely applied in training for emergency preparedness and have long been a feature of Courses on Planning for Nuclear Emergencies. Experience of a large number of table top exercises is used to provide a classification of the types of exercise indicating the application and the disadvantages. The use of workshops is considered to be complementary rather than an alternative to teaching methods available from table top exercises. (author)

  9. International collaboration and comparative research on ocean top predators under CLIOTOP

    Science.gov (United States)

    Hobday, Alistair J.; Arrizabalaga, Haritz; Evans, Karen; Scales, Kylie L.; Senina, Inna; Weng, Kevin C.

    2017-06-01

    Oceanic top predators have ecological, social and economic value of global significance. These wide-ranging marine species, which include sharks, tunas and billfishes, marine mammals, turtles and seabirds, are the focus of international research attention under the Climate Impacts on Oceanic Top Predators (CLIOTOP) science programme, one of the Integrated Marine Biosphere Research (IMBeR) projects. Over more than a decade, research conducted under CLIOTOP has involved scientists from more than 30 countries, with international collaboration increasing markedly over time, and comparative analyses resulting in new knowledge and understanding of oceanic top predators. This special issue presents 27 papers arising from the 3rd CLIOTOP symposium, held in San Sebastián, Spain in September 2015, spanning topics such as conservation biology, trophic ecology, fisheries science, climate change, and adaptive management. The maturation and synthesis of CLIOTOP's collaborative research is now resulting in real-world management applications and improving understanding of potential ecological and socio-economic impacts of climate change in oceanic systems. The ultimate CLIOTOP goal of preparing both climate-sensitive predator populations and the human societies dependent on them for the impending impacts of climate change is now within reach.

  10. Functional responses and scaling in predator-prey interactions of marine fishes: contemporary issues and emerging concepts

    NARCIS (Netherlands)

    Hunsicker, M.E.; Ciannelli, L.; Bailey, K.M.; Buckel, J.A.; White, J.W.; Link, J.S.; Essington, T.E.; Gaichas, S.; Anderson, T.W.; Brodeur, R.D.; Chan, K.S.; Chen, K.; Englund, G.; Frank, K.T.; Freitas, V.; Hixon, M.A.; Hurst, T.; Johnson, D.W.; Kitchell, J.F.; Reese, D.; Rose, G.A.; Sjodin, H.; Sydeman, W.J.; van der Veer, H.W.; Vollset, K.; Zador, S.

    2011-01-01

    Predatorprey interactions are a primary structuring force vital to the resilience of marine communities and sustainability of the worlds oceans. Human influences on marine ecosystems mediate changes in species interactions. This generality is evinced by the cascading effects of overharvesting top

  11. Top Physics at CMS/LHC

    Directory of Open Access Journals (Sweden)

    Daskalakis Georgios

    2017-01-01

    Full Text Available Recent results on the inclusive and differential production cross sections of top-quark pair and single top-quark processes are presented, obtained using data from proton-proton collisions collected with the CMS detector at the LHC. The large centre-of-mass energies available at LHC allow for the copious production of top-quark pairs in association with other final state particles at high transverse momentum. Measurements of such processes as well as of the top-quark mass and other properties will be discussed. The results are compared with the most up-to-date standard model theory predictions.

  12. Differential Top Cross-section Measurements

    CERN Document Server

    Fenton, Michael James; The ATLAS collaboration

    2017-01-01

    The top quark is the heaviest known fundamental particle. The measurement of the differential top-quark pair production cross-section provides a stringent test of advanced perturbative QCD calculations. The ATLAS collaboration has performed detailed measurements of those differential cross sections at a centre-of-mass energy of 13 TeV. This talk focuses on differential cross-section measurements in the lepton+jets final state, including using boosted top quarks to probe our understanding of top quark production in the TeV regime.

  13. Top quark production cross-section measurements

    CERN Document Server

    Chen, Ye; The ATLAS collaboration

    2017-01-01

    Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production cross-section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of ...

  14. Multi-objective entropy evolutionary algorithm for marine oil spill detection using cosmo-skymed satellite data

    OpenAIRE

    M. Marghany

    2015-01-01

    Oil spill pollution has a substantial role in damaging the marine ecosystem. Oil spill that floats on top of water, as well as decreasing the fauna populations, affects the food chain in the ecosystem. In fact, oil spill is reducing the sunlight penetrates the water, limiting the photosynthesis of marine plants and phytoplankton. Moreover, marine mammals for instance, disclosed to oil spills their insulating capacities are reduced, and so making them more v...

  15. Characterization of the Cloud-Topped Boundary Layer at the Synoptic Scale Using AVHRR Observations during the SEMAPHORE Experiment.

    Science.gov (United States)

    Mathieu, A.; Sèze, G.; Lahellec, A.; Guerin, C.; Weill, A.

    2003-12-01

    Satellite platforms NOAA-11 and -12 Advanced Very High Resolution Radiometer (AVHRR) data are used during the daytime to study large sheets of stratocumulus over the North Atlantic Ocean. The application concerns an anticyclonic period of the Structure des Echanges Mer Atmosphère, Propriétés des Hétérogénéités Océaniques: Recherché Expérimentale (SEMAPHORE) campaign (10 17 November 1993). In the region of interest, the satellite images are recorded under large solar zenith angles. Extending the SEMAPHORE area, a region of about 3000 × 3000 km2 is studied to characterize the atmospheric boundary layer. A statistical cloud classification method is applied to discriminate for low-level and optically thick clouds. For AVHRR pixels covered with thick clouds, brightness temperatures are used to evaluate the boundary layer cloud-top temperature (CTT). The objective is to obtain accurate CTT maps for evaluation of a global model. In this application, the full-resolution fields are reduced to match model grid size. An estimate of overall temperature uncertainty associated with each grid point is also derived, which incorporates subgrid variability of the fields and quality of the temperature retrieval. Results are compared with the SEMAPHORE campaign measurements. A comparison with “DX” products obtained with the same dataset, but at lower resolution, is also presented. The authors claim that such instantaneous CTT maps could be as intensively used as classical SST maps, and both could be efficiently complemented with gridpoint error-bar maps. They may be used for multiple applications: (i) to provide a means to improve numerical weather prediction and climatological reanalyses, (ii) to represent a boundary layer global characterization to analyze the synoptic situation of field experiments, and (iii) to allow validation and to test development of large-scale and mesoscale models.

  16. Marine Mammal Protection Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Mammal Protection Act (MMPA or Act) prohibits, with certain exceptions, the "take" of marine mammals in U.S. waters and by U.S. citizens on the high seas,...

  17. Marine gamma spectrometric survey

    International Nuclear Information System (INIS)

    Kostoglodov, V.V.

    1979-01-01

    Presented are theoretical problems physical and geochemical prerequisites and possibilities of practical application of the method of continuous submarine gamma-spectrometric survey and radiometric survey destined for rapid study of the surface layer of marine sediments. Shown is high efficiency and advantages of this method in comparison with traditional and widely spread in marine geology methods of bottom sediments investigation

  18. Marine palynology in progress

    NARCIS (Netherlands)

    Manten, A.A.

    1966-01-01

    One of the things which the Second International Conference on Palynology (held in Utrecht, August 29-September 3, 1966) revealed, was the rapid expansion which marine palynological research has undergone in recent years. This was the main stimulus to organize this special issue of Marine

  19. Top-down and bottom-up aerosol-cloud closure: towards understanding sources of uncertainty in deriving cloud shortwave radiative flux

    Science.gov (United States)

    Sanchez, Kevin J.; Roberts, Gregory C.; Calmer, Radiance; Nicoll, Keri; Hashimshoni, Eyal; Rosenfeld, Daniel; Ovadnevaite, Jurgita; Preissler, Jana; Ceburnis, Darius; O'Dowd, Colin; Russell, Lynn M.

    2017-08-01

    , satellite-derived cloud droplet number concentrations (CDNCs) were within 30 % of simulated CDNC. In cases with a well-mixed boundary layer, δRF is no greater than 20 W m-2 after accounting for cloud-top entrainment and up to 50 W m-2 when entrainment is not taken into account. In cases with a decoupled boundary layer, cloud microphysical properties are inconsistent with ground-based aerosol measurements, as expected, and δRF is as high as 88 W m-2, even high (> 30 W m-2) after accounting for cloud-top entrainment. This work demonstrates the need to take in situ measurements of aerosol properties for cases where the boundary layer is decoupled as well as consider cloud-top entrainment to accurately model stratocumulus cloud radiative flux. 1The regulatory term for UAV is remotely piloted aircraft (RPA).

  20. Top-down and Bottom-up aerosol-cloud-closure: towards understanding sources of unvertainty in deriving cloud radiative flux

    Science.gov (United States)

    Sanchez, K.; Roberts, G.; Calmer, R.; Nicoll, K.; Hashimshoni, E.; Rosenfeld, D.; Ovadnevaite, J.; Preissler, J.; Ceburnis, D.; O'Dowd, C. D. D.; Russell, L. M.

    2017-12-01

    accounting for cloud-top entrainment. This work demonstrates the need to take in-situ measurements of aerosol properties for cases where the boundary layer is decoupled as well as consider cloud-top entrainment to accurately model stratocumulus cloud radiative flux.

  1. Temporal dynamics of top predators interactions in the Barents Sea.

    Science.gov (United States)

    Durant, Joël M; Skern-Mauritzen, Mette; Krasnov, Yuri V; Nikolaeva, Natalia G; Lindstrøm, Ulf; Dolgov, Andrey

    2014-01-01

    The Barents Sea system is often depicted as a simple food web in terms of number of dominant feeding links. The most conspicuous feeding link is between the Northeast Arctic cod Gadus morhua, the world's largest cod stock which is presently at a historical high level, and capelin Mallotus villosus. The system also holds diverse seabird and marine mammal communities. Previous diet studies may suggest that these top predators (cod, bird and sea mammals) compete for food particularly with respect to pelagic fish such as capelin and juvenile herring (Clupea harengus), and krill. In this paper we explored the diet of some Barents Sea top predators (cod, Black-legged kittiwake Rissa tridactyla, Common guillemot Uria aalge, and Minke whale Balaenoptera acutorostrata). We developed a GAM modelling approach to analyse the temporal variation diet composition within and between predators, to explore intra- and inter-specific interactions. The GAM models demonstrated that the seabird diet is temperature dependent while the diet of Minke whale and cod is prey dependent; Minke whale and cod diets depend on the abundance of herring and capelin, respectively. There was significant diet overlap between cod and Minke whale, and between kittiwake and guillemot. In general, the diet overlap between predators increased with changes in herring and krill abundances. The diet overlap models developed in this study may help to identify inter-specific interactions and their dynamics that potentially affect the stocks targeted by fisheries.

  2. Top-Down Control of Diesel-Degrading Prokaryotic Communities.

    Science.gov (United States)

    Sauret, Caroline; Böttjer, Daniela; Talarmin, Agathe; Guigue, Catherine; Conan, Pascal; Pujo-Pay, Mireille; Ghiglione, Jean-François

    2015-08-01

    Biostimulation through the addition of inorganic nutrients has been the most widely practiced bioremediation strategy in oil-polluted marine waters. However, little attention has so far been paid to the microbial food web and the impact of top-down control that directly or indirectly influences the success of the bioremediation. We designed a mesocosm experiment using pre-filtered (diesel fuel. Prokaryotes, HNF and VLP abundances showed a predator-prey succession, with a co-development of HNF and VLP. In the polluted system, we observed a stronger impact of viral lysis on prokaryotic abundances than in the control. Analysis of the diversity revealed that a bloom of Vibrio sp. occurred in the polluted mesocosm. That bloom was rapidly followed by a less abundant and more even community of predation-resistant bacteria, including known hydrocarbon degraders such as Oleispira spp. and Methylophaga spp. and opportunistic bacteria such as Percisivirga spp., Roseobacter spp. and Phaeobacter spp. The shift in prokaryotic dominance in response to viral lysis provided clear evidence of the 'killing the winner' model. Nevertheless, despite clear effects on prokaryotic abundance, activity and diversity, the diesel degradation was not impacted by top-down control. The present study investigates for the first time the functioning of a complex microbial network (including VLP) using a nutrient-based biostimulation strategy and highlights some key processes useful for tailoring bioremediation.

  3. High Performance Marine Vessels

    CERN Document Server

    Yun, Liang

    2012-01-01

    High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

  4. Scenario-based table top simulations

    DEFF Research Database (Denmark)

    Broberg, Ole; Edwards, Kasper; Nielsen, J.

    2012-01-01

    This study developed and tested a scenario-based table top simulation method in a user-driven innovation setting. A team of researchers worked together with a user group of five medical staff members from the existing clinic. Table top simulations of a new clinic were carried out in a simple model...

  5. Experimental results on SUSY searches with top

    CERN Document Server

    Eifert, Till

    2014-01-01

    Searches for supersymmetric partner particles of the top and bottom quarks at the Large Hadron Collider are reviewed. The focus is on the status of searches for a relatively light partner of the top quark performed by the CMS and ATLAS Collaborations. No excess beyond Standard Model expectations is observed and exclusion limits are set on the masses of supersymmetric particles.

  6. Top quark property measurements at the LHC

    CERN Document Server

    Hawkings, Richard; The ATLAS collaboration

    2014-01-01

    Measurements of top quark properties performed at the Large Hadron Collider are reviewed, with a particular emphasis on top-pair charge asymmetries, spin correlations and polarization measurements performed by the ATLAS and CMS collaborations. The measurements are generally in good agreement with predictions from next-to-leading-order QCD calculations, and no deviations from Standard Model expectations have been seen.

  7. Top quark distributions in hadronic collisions

    CERN Document Server

    Frixione, Stefano; Nason, P; Ridolfi, G; Frixione, S; Mangano, M L; Nason, P; Ridolfi, G

    1995-01-01

    We present kinematical distributions for top quark pairs produced at the Tevatron \\ppbar\\ Collider, as predicted within Next-to-Leading-Order QCD. We consider single and double-inclusive distributions, and compare our results to those obtained with the shower Monte Carlo HERWIG. We discuss the implications of our findings for experimental issues such as the measurement of the top quark mass.

  8. Top 12 Web Resources for 2012

    Science.gov (United States)

    Gonzales, Lisa; Vodicka, Devin

    2012-01-01

    In this article, the authors describe some of the top websites recommended by colleagues for the Association of California School Administrators. The Top 12 for 2012 are: (1) Facebook (facebook.com); (2) Twitter (twitter.com); (3) Tungle (tungle.me); (4) FCMAT (fcmat.org); (5) YouSendIt (yousendit.com); (6) Slideshare (slideshare.net); (7) QR…

  9. Latest ATLAS measurements on top quark properties

    CERN Document Server

    Derue, Frederic; The ATLAS collaboration

    2017-01-01

    The top quark is unique among the known quarks in that it decays before it has an opportunity to form hadronic bound states. This makes measurements of its properties particularly interesting as one can access directly the properties of a bare quark. The latest measurements of these properties with the ATLAS detector at the LHC are presented using 8 TeV and 13 TeV data, excluding results from single top production. Measurements of top quark spin observables in top-antitop events, each sensitive to a different coefficient of the spin density matrix, are presented and compared to the Standard Model predictions. The helicity of the W boson from the top decays and the production angles of the top quark are further discussed. New results on the measurment of color flow effects in $t{\\bar t}$ events are presented. Limits on the rate of flavour changing neutral currents in the production or decay of the top quark are reported. The cross-section measurement of photons produced in association with top-quark pairs is a...

  10. Thermal design of top shield for PFBR

    International Nuclear Information System (INIS)

    Gajapathy, R.; Jalaludeen, S.; Selvaraj, A.; Bhoje, S.B.

    1988-01-01

    India's Liquid Metal Cooled Fast Breeder Reactor programme started with the construction of loop type 13MW(e) Fast Breeder Test Reactor (FBTR) which attained criticality in October 1985. With the experience of FBTR, the design work on pool type 500 MW(e) Prototype Fast Breeder Reactor (PFBR) which will be a forerunner for future commercial fast breeder reactors, has been started. The Top Shield forms the cover for the main vessel which contains the primary circuit. Argon cover gas separates the Top Shield from the free level of hot sodium pool (803K). The Top Shield which is of box type construction consists of control plug, two rotatable plugs and roof slab, assembled together, which provide biological shielding, thermal shielding and leak tight containment at the top of the main vessel. Heat is transferred from the sodium pool to the Top Shield through argon cover gas and through components supported by it and dipped in the sodium pool. The Top Shield should be maintained at the desired operating temperature by incorporating a cooling system inside it. Insulation may be provided below the bottom plate to reduce the heat load to the cooling system, if required. The thermal design of Top Shield consists of estimation of heat transfer to the Top Shield, selection of operating temperature, assessment of insulation requirement, design of cooling system and evaluation of transient temperature changes

  11. SWFSC/MMTD/CCE: Tagging and Tracking of Physeter (T-TOP/T-TOP2) 1997

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This research was devoted to studying sperm whale (Physeter macrocephalus) behavior. The principal study area for T-TOP and T-TOP2 was the Pioneer Seamount, 50...

  12. Measuring top-quark polarization in top-pair + missing-energy events.

    Science.gov (United States)

    Berger, Edmond L; Cao, Qing-Hong; Yu, Jiang-Hao; Zhang, Hao

    2012-10-12

    The polarization of a top quark can be sensitive to new physics beyond the standard model. Since the charged lepton from top-quark decay is maximally correlated with the top-quark spin, it is common to measure the polarization from the distribution in the angle between the charged lepton and the top-quark directions. We propose a novel method based on the charged lepton energy fraction and illustrate the method with a detailed simulation of top-quark pairs produced in supersymmetric top squark pair production. We show that the lepton energy ratio distribution that we define is very sensitive to the top-quark polarization but insensitive to the precise measurement of the top-quark energy.

  13. Top quark mass measurement in dilepton channel

    International Nuclear Information System (INIS)

    Lysak, R.

    2007-01-01

    In this work, we measured the top quark mass in tt'-' events produced in pp'-' interactions at the center-of-mass energy 1.96 TeV using CDF detector. We used dilepton in tt'-' events where both W bosons from top quarks are decaying into leptons. The data sample corresponds to 340 pb -1 . We found there 33 tt'-' candidates while expecting 10.5 ± 1.9 background events. In the measurement, we reconstruct one, representative mass for each event using the assumption about longitudinal momentum of in tt'-' system, in order to be able to kinematically solve the under-constrained system. The mass distributions (templates) are created for simulated signal and background events. Templates are parametrized in order to obtain smooth probability density functions. Likelihood maximization which includes these parametrized templates is then performed on reconstructed masses obtained from data sample in order to obtain final top quark mass estimate. The result of applying this procedure on data events is top quark mass estimate 169.5 +7. 7 - 7.2 (stat.) ± 4.0(syst.) GeV/c 2 for 30 out of 33 candidates, where the solution for top quark mass was found. This measurement was a part of first top quark mass measurement in dilepton channel at CDF in Run II. The top quark mass measured here is consistent with the CDF measurement in dilepton channel from Run I M top = 167.4 ± 10.3(stat.) ± 4.8(syst.) GeV/c 2 . Moreover, the combined result of four top quark mass measurements in dilepton channel from Run II (one of these four measurements is our measurement) M top = 167.9 ± 5.2(stat.) ± 3.7(syst.) GeV/c 2 significantly (by ∼ 40%) improved the precision of top quark mass determination from Run I. It should be also noted, that this combined result is consistent with measurement obtained in 'lepton+jets' channel at CDF in Run II (M top = 173.5 +3.9 -3.8 GeV/c 2 ). So, we don't have yet any indication about new physics beyond the Standard Model. My main contribution in this analysis was

  14. Top quark studies with the ATLAS detector

    CERN Document Server

    Capua, Marcella; The ATLAS collaboration

    2015-01-01

    The latest top quark studies in proton-proton collisions at a centre-of-mass energy of 7 and 8 TeV with the ATLAS detector are reported. We present recent results on the top pair production inclusive cross-sections, top pair production differential cross-section in the resolved and boosted regimes, single top-quark production cross-sections measured in the t-channel, s-channel and W-boson associated processes, as well as the CKM matrix element $|V_{tb}|$ determination. The results are compared with theoretical expectations. Latest ATLAS results on top properties will be also shown in terms of direct and mass pole, spin correlations and charge asymmetry.

  15. Top quark studies with the ATLAS detector

    CERN Document Server

    Capua, Marcella; The ATLAS collaboration

    2015-01-01

    The latest studies of top quark production measurement in proton-proton collisions at a centre-of-mass energy of 7 and 8 TeV with the ATLAS detector are reported. The talk will present recent results on the top pair production inclusive cross sections, top pair production differential cross section in resolved and boosted regime, single top-quark productions cross sections measured for t-channel, s-channel and W-boson associated processes. as well as d the CKM matrix element |Vtb| determination. All the results are compared with theoretical expectations. Latest ATLAS results on top mass measurements will be also shown in terms of direct and mass pole results.

  16. TOP500 Supercomputers for June 2002

    Energy Technology Data Exchange (ETDEWEB)

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2002-06-20

    19th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 19th edition of the TOP500 list of the worlds fastest supercomputers was released today (June 20, 2002). The recently installed Earth Simulator supercomputer at the Earth Simulator Center in Yokohama, Japan, is as expected the clear new number 1. Its performance of 35.86 Tflop/s (trillions of calculations per second) running the Linpack benchmark is almost five times higher than the performance of the now No.2 IBM ASCI White system at Lawrence Livermore National Laboratory (7.2 Tflop/s). This powerful leap frogging to the top by a system so much faster than the previous top system is unparalleled in the history of the TOP500.

  17. Top quark production at the LHC

    CERN Document Server

    Ferreira da Silva, Pedro

    2016-01-01

    Twenty years past its discovery, the top quark continues attracting great interest as experiments keep unveiling its properties. An overview of the latest measurements in the domain of top quark production, performed by the ATLAS and CMS experiments at the CERN LHC, is given. The latest measurements of top quark production rates via strong and electroweak processes are reported and compared to different perturbative QCD predictions. Fundamental properties, such as the mass or the couplings of the top quark, as well as re-interpretations seeking for beyond the standard model contributions in the top quark sector, are extracted from these measurements. In each case an attempt to highlight the first results and main prospects for the on-going Run 2 of the LHC is made.

  18. D OE top quark mass analysis

    International Nuclear Information System (INIS)

    Strovink, M.

    1995-07-01

    Based on (44-48 pb -1 ) of lepton + jets data, we review D0's initial analysis of the top quark mass. The result, M top = 199 ± 19/21 (stat.) ± 22 (syst.) GeV/c 2 , is insensitive to background normalization. The errors are based on ISAJET top Monte Carlo, with its more severe gluon radiation, and allow for ISAJET/HERWIG differences. Good progress is being made in reducing the systematic error. We present a new study based on two-dimensional distributions of reconstructed top quark vs. dijet mass. With 98.7% confidence we observe a peak in the top mass - dijet mass plane. The peak and its projections are similar both in shape and magnitude to expectations based on the decay sequence 1 → bW, W → jj

  19. Top quark production at the LHC (single top and tt-bar cross sections)

    International Nuclear Information System (INIS)

    Lange, J.

    2014-01-01

    With the large number of top quarks produced at the LHC, top quark physics enters an era of precision and properties measurements. This article reviews the recent advances in top quark cross section measurements performed by ATLAS and CMS using data recorded in 2011 with integrated luminosities up to 5 fb -1 . They include precision inclusive cross sections, the establishment of challenging channels, first differential cross section measurements and single top production. An overall good agreement with Standard Model predictions is observed

  20. Marine Viruses: Key Players in Marine Ecosystems

    Directory of Open Access Journals (Sweden)

    Mathias Middelboe

    2017-10-01

    Full Text Available Viruses were recognized as the causative agents of fish diseases, such as infectious pancreatic necrosis and Oregon sockeye disease, in the early 1960s [1], and have since been shown to be responsible for diseases in all marine life from bacteria to protists, mollusks, crustaceans, fish and mammals [2].[...

  1. Marine Invertebrates: Communities at Risk

    Directory of Open Access Journals (Sweden)

    Jennifer Mather

    2013-06-01

    Full Text Available Our definition of the word ‘animal’ centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org has recently conducted an extensive audit of marine ecosystems, we still do not understand much about the animals of the seas. Surveys of the best-known ecosystems, in which invertebrate populations often play a key role, show that the invertebrate populations are affected by human impact. Coral animals are the foundation of coral reef systems, which are estimated to contain 30% of the species in the ocean. Physical impact and chemical changes on the water severely damage these reefs, and may lead to the removal of these important habitats. Tiny pteropod molluscs live in huge numbers in the polar seas, and their fragile shells are particularly vulnerable to ocean acidification. Their removal would mean that fishes on which we depend would have a hugely diminished food supply. In the North Sea, warming is leading to replacement of colder water copepods by warmer water species which contain less fat. This is having an effect on the birds which eat them, who enrich the otherwise poor land on which they nest. Conversely, the warming of the water and the loss of top predators such as whales and sharks has led to an explosion of the jumbo squid of the Pacific coast of North America. This is positive in the development of a squid fishery, yet negative because the squid eat fish that have been the mainstay of the fishery along that coast. These examples show how invertebrates are key in the oceans, and what might happen when global changes impact them.

  2. Marine invertebrates: communities at risk.

    Science.gov (United States)

    Mather, Jennifer

    2013-06-10

    Our definition of the word 'animal' centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org) has recently conducted an extensive audit of marine ecosystems, we still do not understand much about the animals of the seas. Surveys of the best-known ecosystems, in which invertebrate populations often play a key role, show that the invertebrate populations are affected by human impact. Coral animals are the foundation of coral reef systems, which are estimated to contain 30% of the species in the ocean. Physical impact and chemical changes on the water severely damage these reefs, and may lead to the removal of these important habitats. Tiny pteropod molluscs live in huge numbers in the polar seas, and their fragile shells are particularly vulnerable to ocean acidification. Their removal would mean that fishes on which we depend would have a hugely diminished food supply. In the North Sea, warming is leading to replacement of colder water copepods by warmer water species which contain less fat. This is having an effect on the birds which eat them, who enrich the otherwise poor land on which they nest. Conversely, the warming of the water and the loss of top predators such as whales and sharks has led to an explosion of the jumbo squid of the Pacific coast of North America. This is positive in the development of a squid fishery, yet negative because the squid eat fish that have been the mainstay of the fishery along that coast. These examples show how invertebrates are key in the oceans, and what might happen when global changes impact them.

  3. Measurements and searches with top quarks

    International Nuclear Information System (INIS)

    Peters, Reinhild Yvonne

    2008-01-01

    In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t(bar t)H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more channels

  4. Discovery of single top quark production

    Energy Technology Data Exchange (ETDEWEB)

    Gillberg, Dag [Simon Fraser Univ., Burnaby, BC (Canada)

    2009-04-01

    The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking - the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of single top quark production. An analysis is performed using 2.3 fb-1 of data recorded by the D0 detector at the Fermilab Tevatron Collider at centre-of-mass energy √s = 1.96 TeV. Boosted decision trees are used to isolate the single top signal from background, and the single top cross section is measured to be σ(p$\\bar{p}$ → tb + X, tqb + X) = 3.74-0.74+0.95 pb. Using the same analysis, a measurement of the amplitude of the CKM matrix element Vtb, governing how top and b quarks mix, is also performed. The measurement yields: |V{sub tb}|f1L| = 1.05 -0.12+0.13, where f1L is the left-handed Wtb coupling. The separation of signal from background is improved by combining the boosted decision trees with two other multivariate techniques. A new cross section measurement is performed, and the significance for the excess over the predicted background exceeds 5

  5. Seawater and marine sidements

    International Nuclear Information System (INIS)

    Eicke, H.F.

    1985-01-01

    The Deutsches Hydrographisches Institut (DHI) is responsible for monitoring the radioactive substances (such as Cs-137, Cs-134, Sr-90, H-3, Pu-239, Pu-240) in the seawater and marine sediments along the Federal German seacoasts, of the fishing grounds of the Federal German offshore fishery industry, and of marine currents moving towards these fishing grounds. The DHI has been carrying out this task since 1965, activities being placed under the responsibility of the DHI Department for Marine Radioactivity, which since 1960 is a directing centre within the Government's system for environmental radioactivity monitoring. (orig./DG) [de

  6. Marine Mineral Exploration

    DEFF Research Database (Denmark)

    in EEZ areas are fairly unknown; many areas need detailed mapping and mineral exploration, and the majority of coastal or island states with large EEZ areas have little experience in exploration for marine hard minerals. This book describes the systematic steps in marine mineral exploration....... Such exploration requires knowledge of mineral deposits and models of their formation, of geophysical and geochemical exploration methods, and of data evaluation and interpretation methods. These topics are described in detail by an international group of authors. A short description is also given of marine...

  7. Will marine productivity wane?

    Science.gov (United States)

    Laufkötter, Charlotte; Gruber, Nicolas

    2018-03-01

    If marine algae are impaired severely by global climate change, the resulting reduction in marine primary production would strongly affect marine life and the ocean's biological pump that sequesters substantial amounts of atmospheric carbon dioxide in the ocean's interior. Most studies, including the latest generation of Earth system models, project only moderate global decreases in biological production until 2100 (1, 2), suggesting that these concerns are unwarranted. But on page 1139 of this issue, Moore et al. (3) show that this conclusion might be shortsighted and that there may be much larger long-term changes in ocean productivity than previously appreciated.

  8. The Top Quark, QCD, And New Physics.

    Science.gov (United States)

    Dawson, S.

    2002-06-01

    The role of the top quark in completing the Standard Model quark sector is reviewed, along with a discussion of production, decay, and theoretical restrictions on the top quark properties. Particular attention is paid to the top quark as a laboratory for perturbative QCD. As examples of the relevance of QCD corrections in the top quark sector, the calculation of e{sup+}e{sup -}+ t{bar t} at next-to-leading-order QCD using the phase space slicing algorithm and the implications of a precision measurement of the top quark mass are discussed in detail. The associated production of a t{bar t} pair and a Higgs boson in either e{sup+}e{sup -} or hadronic collisions is presented at next-to-leading-order QCD and its importance for a measurement of the top quark Yulrawa coupling emphasized. Implications of the heavy top quark mass for model builders are briefly examined, with the minimal supersymmetric Standard Model and topcolor discussed as specific examples.

  9. Top Quark Mass Measurement in Dilepton Channel

    Energy Technology Data Exchange (ETDEWEB)

    Lysak, Roman [Inst. of Experimental Physics, Kosice (Slovak Republic)

    2007-06-01

    We present a measurement of the top quark mass from events produced in p$\\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. We identify t$\\bar{t}$ candidates where both W bosons from the top quarks decay into leptons (eν, µν, τν) from a data sample of 340 pb-1. The top quark mass is reconstructed in each event separately by the method which draw upon simulated distribution of t$\\bar{t}$ longitudinal momentum in order to extract probability distribution for the top quark mass. Representative distributions, or templates, are constructed from simulated samples of signal and background events, and parametrized to form continuous probability density functions. A likelihood fit incorporating these parametrized templates is then performed on the data sample masses in order to derive a final top quark mass. Measured top quark mass is Mtop = 169.5$+7.7\\atop{-7.2}$(stat.) ± 4.0(syst.) GeV/c2.

  10. Measurement of the top quark mass

    International Nuclear Information System (INIS)

    Blusk, Steven R.

    1998-01-01

    The first evidence and subsequent discovery of the top quark was reported nearly 4 years ago. Since then, CDF and D0 have analyzed their full Run 1 data samples, and analysis techniques have been refined to make optimal use of the information. In this paper, we report on the most recent measurements of the top quark mass, performed by the CDF and D0 collaborations at the Fermilab Tevatron. The CDF collaboration has performed measurements of the top quark mass in three decay channels from which the top quark mass is measured to be 175.5 ± 6.9 GeV=c 2 . The D0 collaboration combines measurements from two decay channels to obtain a top quark mass of 172.1 ± 7.1 GeV/c 2 . Combining the measurements from the two experiments, assuming a 2 GeV GeV/c 2 correlated systematic uncertainty, the measurement of the top quark mass at the Tevatron is 173.9 ± 5.2 GeV/c 2 . This report presents the measurements of the top quark mass from each of the decay channels which contribute to this measurement

  11. 76 FR 76949 - Marine Mammals

    Science.gov (United States)

    2011-12-09

    ...-XR52 Marine Mammals AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric.... 14534 is requested under the authority of the Marine Mammal Protection Act of 1972, as amended (16 U.S.C. 1361 et seq.), the regulations governing the taking and importing of marine mammals (50 CFR part 216...

  12. 75 FR 68605 - Marine Mammals

    Science.gov (United States)

    2010-11-08

    ...-XX23 Marine Mammals AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... permit to conduct research on marine mammals. ADDRESSES: The permit and related documents are available... applicant. The requested permit has been issued under the authority of the Marine Mammal Protection Act of...

  13. 77 FR 2512 - Marine Mammals

    Science.gov (United States)

    2012-01-18

    ...-XA905 Marine Mammals AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Dorian Houser, Ph.D., National Marine Mammal Foundation, 2240 Shelter Island Drive, 200, San Diego, CA... subject permit is requested under the authority of the Marine Mammal Protection Act of 1972, as amended...

  14. 77 FR 14352 - Marine Mammals

    Science.gov (United States)

    2012-03-09

    ...-XB065 Marine Mammals AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Marine Mammal Protection Act of 1972, as amended (16 U.S.C. 1361 et seq.), the regulations governing the taking and importing of marine mammals (50 CFR part 216), the Endangered Species Act of 1973, as amended...

  15. 75 FR 77616 - Marine Mammals

    Science.gov (United States)

    2010-12-13

    .... 14334] Marine Mammals AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Marine Mammal Protection Act of 1972, as amended (16 U.S.C. 1361 et seq.), the regulations governing the taking and importing of marine mammals (50 CFR part 216), the Endangered Species Act of 1973, as amended...

  16. Hadronization systematics and top mass reconstruction

    Directory of Open Access Journals (Sweden)

    Corcella Gennaro

    2014-01-01

    Full Text Available I discuss a few issues related to the systematic error on the top mass mea- surement at hadron colliders, due to hadronization effects. Special care is taken about the impact of bottom-quark fragmentation in top decays, especially on the reconstruction relying on final states with leptons and J/Ψ in the dilepton channel. I also debate the relation between the measured mass and its theoretical definition, and report on work in progress, based on the Monte Carlo simulation of fictitious top-flavoured hadrons, which may shed light on this issue and on the hadronization systematics.

  17. TOP500 Supercomputers for June 2005

    Energy Technology Data Exchange (ETDEWEB)

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2005-06-22

    25th Edition of TOP500 List of World's Fastest Supercomputers Released: DOE/L LNL BlueGene/L and IBM gain Top Positions MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 25th edition of the TOP500 list of the world's fastest supercomputers was released today (June 22, 2005) at the 20th International Supercomputing Conference (ISC2005) in Heidelberg Germany.

  18. Top quark pair production in ATLAS

    CERN Document Server

    Moreno Llacer, M; The ATLAS collaboration

    2010-01-01

    Top-quark pairs are expected to be produced at the LHC, even at the lower beam energy and luminosity in the first years of running. Establishing the top-pair signal and measuring the production cross-section are important benchmarks for ATLAS, and will help understand the detector performance for events with high-pT leptons, high jet multiplicity, missing transverse energy. The prospects for early top physics measurements will be shown, with a particular emphasis on the progress achieved with data so far.

  19. Search for top in UA2

    International Nuclear Information System (INIS)

    Repellin, J.P.

    1989-01-01

    A search for the top quark in the data collected during 1988 by the UA2 collaboration at the CERN proton-antiproton collider is presented. In UA2 the selected decay mode is t → eν-barb. The present report is limited to the study of topologies with an electron, a neutrino, and two or more jets. With an integrated luminosity of 2.5 pb -1 the data do not show any contribution from top and at this preliminary stage of the analysis a top mass between 30 and 60 GeV seems excluded. (K.A.) 9 refs.; 9 figs.; 2 tabs

  20. Precision Determination of the Top Quark Mass

    Energy Technology Data Exchange (ETDEWEB)

    Movilla Fernandez, Pedro A.; /LBL, Berkeley

    2007-05-01

    The CDF and D0 collaborations have updated their measurements of the mass of the top quark using proton-antiproton collisions at {radical}s = 1.96 TeV produced at the Tevatron. The uncertainties in each of the top-antitop decay channels have been reduced. The new Tevatron average for the mass of the top quark based on about 1 fb{sup -1} of data per experiment is 170.9 {+-} 1.8 GeV/c{sup 2}.

  1. Top quark mass measurement at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes da Costa, Joao; /Harvard U.

    2004-12-01

    The authors report on the latest experimental measurements of the top quark mass by the CDF and D0 Collaborations at the Fermilab Tevatron. They present a new top mass measurement using the t{bar t} events collected by the D0 Collaboration in Run I between 1994 and 1996. This result is combined with previous measurements to yield a new world top mass average. They also describe several preliminary results using up to 193 pb{sup -1} of t{bar t} events produced in {bar p}p collisions at {radical}s = 1.96 TeV during the Run II of the Tevatron.

  2. Global constraints on top quark anomalous couplings

    Science.gov (United States)

    Déliot, Frédéric; Faria, Ricardo; Fiolhais, Miguel C. N.; Lagarelhos, Pedro; Onofre, António; Pease, Christopher M.; Vasconcelos, Ana

    2018-01-01

    The latest results on top quark physics, namely single top quark production cross sections, W -boson helicity and asymmetry measurements are used to probe the Lorentz structure of the W t b vertex. The increase of sensitivity to new anomalous physics contributions to the top quark sector of the standard model is quantified by combining the relevant results from Tevatron and the Large Hadron Collider. The results show that combining an increasing set of available precision measurements in the search for new physics phenomena beyond the standard model leads to significant sensitivity improvements, especially when compared with the current expectation for the High Luminosity run at the LHC.

  3. The de Sitter relativistic top theory

    International Nuclear Information System (INIS)

    Armenta, J.; Nieto, J.A.

    2005-01-01

    We discuss the relativistic top theory from the point of view of the de Sitter (or anti-de Sitter) group. Our treatment rests on the Hanson-Regge spherical relativistic top Lagrangian formulation. We propose an alternative method for studying spinning objects via Kaluza-Klein theory. In particular, we derive the relativistic top equations of motion starting with the geodesic equation for a point particle in 4+N dimensions. We compare our approach with Fukuyama's formulation of spinning objects, which is also based on Kaluza-Klein theory. We also report a generalization of our approach to a 4+N+D dimensional theory

  4. New Physics in Single-Top Production

    CERN Document Server

    Lohse, T; The ATLAS collaboration

    2014-01-01

    In this paper an overview of recent results on the search for physics beyond the Standard Model in the electro-weak top-quark production from the ATLAS, D0 , CDF and CMS collaborations is given. This includes searches for W' and b$^∗$ resonances as well as measurements of CP violation, the W helicity fractions and the top-quark polarisation in single-top production. A brief review on the search for flavour-changing neutral currents and cross-section measurements with respect to the CKM matrix element $V_{tb}$ is given.

  5. Top physics in ATLAS and CMS

    CERN Document Server

    Diez, Carmen

    2018-01-01

    A selection of recent results of top quark production performed by the ATLAS and CMS Collaborations at the LHC is presented. The results include measurements of top quark pair production, including inclusive and differential cross sections, as well as cross sections for ${\\rm t\\bar{t}}$ production in association with additional heavy-quark jets or additional bosons. The production of single top quarks via t-channel, tW associated production, and in association with a Z boson is also discussed. The results discussed are mostly obtained using data collected in proton-proton collisions at centre-of-mass energies of 8 and 13 TeV.

  6. Women in Top Management and Firm Performance

    DEFF Research Database (Denmark)

    Smith, Nina; Smith, Valdemar; Verner, Mette

    -observations for all Danish firms with more than 50 employees over the period 1994-2003, the analysis suggests that the proportion of women in top management jobs has from none to positive influence on firm performance. However, the results show that the strength of the effects of women in top management depends...... on how top CEOs are defined and on the method of estimation of the model. Next, the results point towards a positive influence on firm performance of the staff representation in the supervisory board of the firm but more women representing the shareholders in the supervisory board of the firm seems...

  7. Toiduainetööstuse TOP 100 aastal 2000

    Index Scriptorium Estoniae

    2001-01-01

    Toiduainetööstuse käibe TOP 75; Toiduainetööstuse käibekasvu TOP 60; Toiduainetööstuse kasumi TOP 80; Kahjumi TOP 15; Toiduainetööstuse kasumi kasvu TOP 60; Rentaabluse TOP 50; varade tootlikkuse TOP 50; Toiduainetööstuse finantsandmed aastal 2000; Toiduainetööstuse üldandmed aastal 2000

  8. IAEA Monitors Marine Radioactivity

    International Nuclear Information System (INIS)

    Dixit, Aabha; Kaiser, Peter

    2013-01-01

    The IAEA assists Member States in using scientific tools to precisely identify and track nuclear and nonnuclear contaminants, as well as to investigate their biological effects on the marine ecosystem

  9. Permitted Marine Hydrokinetic Projects

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data represents pending or issued preliminary permits or issued licenses for marine hydrokinetic projects that produce energy from waves or directly from the...

  10. The marine cyanobacterium

    NARCIS (Netherlands)

    Pade, N.; Compaoré, J.; Klähn, S.; Stal, L.J.; Hagemann, M.

    2012-01-01

    Compatible solutes are small organic molecules that are involved in the acclimation to various stresses such as temperature and salinity. Marine or moderate halotolerant cyanobacteria accumulate glucosylglycerol, while cyanobacteria with low salt tolerance (freshwater strains) usually accumulate

  11. Foodborne Marine Biotoxins

    National Research Council Canada - National Science Library

    Poli, Mark

    2003-01-01

    ...). In addition to human intoxications, they cause massive fish kills, negatively impact coastal tourism and fishery industries, and have been implicated in mass mortalities of birds and marine mammals...

  12. LEGACY - EOP Marine Debris

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data contains towed diver surveys of and weights of marine debris removed from the near shore environments of the NWHI.

  13. Biotechnology of marine fungi

    Digital Repository Service at National Institute of Oceanography (India)

    Damare, S.R.; Singh, P.; Raghukumar, S.

    Filamentous fungi are the most widely used eukaryotes in industrial and pharmaceutical applications. Their biotechnological uses include the production of enzymes, vitamins, polysaccharides, pigments, lipids and others. Marine fungi are a still...

  14. WMO Marine Final Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Final reports of the World Meteorological Organization (WMO) Commission for Marine Meteorology, Commission for Synoptic Meteorology, and Commission for Basic...

  15. PIR Marine Turtle Nesting

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Effective management of marine turtle data is essential to maximize their research value and enable timely population assessments and recovery monitoring. To provide...

  16. PIR Marine Turtle Strandings

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Effective management of marine turtle data is essential to maximize their research value and enable timely population assessments and recovery monitoring. To provide...

  17. Marine Mammals :: NOAA Fisheries

    Science.gov (United States)

    Resources Habitat Conservation Science and Technology International Affairs Law Enforcement Aquaculture Application Types Apply Online (APPS) Endangered Species Permits Marine Mammal Permits Public Display of : NMFS Pacific Islands Fisheries Science Center North Atlantic right whales North Atlantic Right whales

  18. Marine Pollution Prevention Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Pollution Prevention Act of 2008 implements the International Convention for the Prevention of Pollution from Ships, including related Protocols (MARPOL)...

  19. Mariner Outreach Data -

    Data.gov (United States)

    Department of Transportation — This dataset provides MARAD with the ability to determine available personnel and resources in a time of emergency. It also provides a portal for mariners to update...

  20. Marine Sanitation Devices (MSDs)

    Science.gov (United States)

    Marine sanitation devices treat or retain sewage from vessels, and have performance standards set by the EPA. This page provides information on MSDs, including who must use an MSD, states' roles, types of MSDs and standards.

  1. Marine Trackline Geophysical Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains bathymetry, magnetic, gravity and seismic shot point navigation data collected during marine cruises from 1939 to the present. Coverage is...

  2. Marine medicinal glycomics

    Directory of Open Access Journals (Sweden)

    Vitor Hugo Pomin

    2014-01-01

    Full Text Available Glycomics is an international initiative aimed to understand the structure and function of the glycans from a given type of cell, tissue, organism, kingdom or even environment, as found under certain conditions. Glycomics is one of the latest areas of intense biological research. Glycans of marine sources are unique in terms of structure and function. They differ considerably from those of terrestrial origin. This review discusses the most known marine glycans of potential therapeutic properties. They are chitin, chitosan, and sulfated polysaccharides named glycosaminoglycans, sulfated fucans and sulfated galactans. Their medical actions are very broad. When certain structural requirements are found, these glycans can exhibit beneficial effects in inflammation, coagulation, thrombosis, cancer growth/metastasis and vascular biology. Both structure and therapeutic mechanisms of action of these marine glycans are discussed here in straight context with the current glycomic age through a project suggestively named Marine Medicinal Glycomics.

  3. Marine prostanoids - a review

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; De

    The occurrence and structure of prostaglandins including clavulones, punaglandins and claviridenones in marine organisms is reviewEd. by comparison of the spectral data reported the identity of 20-acetoxy claviridenones b and c with 20 acetoxy...

  4. Marine Pollution and Ecotoxicology

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    . Heavy metals Editorial Guest The special issue of Environment International has come up with selected papers presented in the International workshop on Marine Pollution and Ecotoxicology held at the National Institute of Oceanography, Dona Paula, Goa... presented in this special issue are classified into five sections namely, Coastal water quality, Heavy metals, Trace metals, Persistent organic pollutants and Ecotoxicology. 1. Coastal water quality assessment The pollution of the marine environment has...

  5. Marine Anthropogenic Litter

    OpenAIRE

    Bergmann, Melanie; Gutow, Lars; Klages, Michael

    2015-01-01

    This book describes how manmade litter, primarily plastic, has spread into the remotest parts of the oceans and covers all aspects of this pollution problem from the impacts on wildlife and human health to socio-economic and political issues. Marine litter is a prime threat to marine wildlife, habitats and food webs worldwide. The book illustrates how advanced technologies from deep-sea research, microbiology and mathematic modelling as well as classic beach litter counts by volunteers co...

  6. Marine Ecosystem Services

    DEFF Research Database (Denmark)

    Hasler, Berit; Ahtiainen, Heini; Hasselström, Linus

    MARECOS (Marine Ecosystem Services) er et tværfagligt studie, der har haft til formål at tilvejebringe information vedrørende kortlægning og værdisætning af økosystemtjenester, som kan anvendes i forbindelse med udformning af regulering på det marine område såvel nationalt, som regionalt og inter...

  7. Marine Corps Pay Incentives

    Science.gov (United States)

    Marines from 2000 to 2017. The thesis includes a literature review on economic theory related to pay incentives in the Department of Defense, a...The purpose of this thesis to provide the Marine Corps with a comprehensive report on pay incentive programs and special pay that were available to...summarization of pay incentive categories, a data analysis on take-up rates and average annual amounts at the end of each fiscal year, and a program review

  8. Giving top quark effective operators a boost

    CERN Document Server

    Englert, Christoph

    2016-01-01

    We investigate the prospects to systematically improve generic effective field theory-based searches for new physics in the top sector during LHC run 2 as well as the high luminosity phase. In particular, we assess the benefits of high momentum transfer final states on top EFT-fit as a function of systematic uncertainties in comparison with sensitivity expected from fully-resolved analyses focusing on $t\\bar t$ production. We find that constraints are typically driven by fully-resolved selections, while boosted top quarks can serve to break degeneracies in the global fit. This demystifies and clarifies the importance of high momentum transfer final states for global fits to new interactions in the top sector from direct measurements.

  9. Top 10 Myths about Cardiovascular Disease

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More Top 10 Myths about Cardiovascular Disease Updated:Mar 16,2018 How much do ... Healthy This content was last reviewed July 2015. Cardiovascular Conditions • Conditions Home • Arrhythmia and Atrial Fibrillation • Cardiac ...

  10. Queen's discovery lauded by top scientific journal

    CERN Multimedia

    McGrady, S

    2002-01-01

    A scientific breakthrough at Queen's University's Sudbury Neutrino Observatory has received major international recognition. The journal Science ranked the discovery that cracked the "neutrino problem" second, in the journal's top 10 scientific achievements of 2002 (1/2 page).

  11. Improved Marine Waters Monitoring

    Science.gov (United States)

    Palazov, Atanas; Yakushev, Evgeniy; Milkova, Tanya; Slabakova, Violeta; Hristova, Ognyana

    2017-04-01

    IMAMO - Improved Marine Waters Monitoring is a project under the Programme BG02: Improved monitoring of marine waters, managed by Bulgarian Ministry of environment and waters and co-financed by the Financial Mechanism of the European Economic Area (EEA FM) 2009 - 2014. Project Beneficiary is the Institute of oceanology - Bulgarian Academy of Sciences with two partners: Norwegian Institute for Water Research and Bulgarian Black Sea Basin Directorate. The Project aims to improve the monitoring capacity and expertise of the organizations responsible for marine waters monitoring in Bulgaria to meet the requirements of EU and national legislation. The main outcomes are to fill the gaps in information from the Initial assessment of the marine environment and to collect data to assess the current ecological status of marine waters including information as a base for revision of ecological targets established by the monitoring programme prepared in 2014 under Art. 11 of MSFD. Project activities are targeted to ensure data for Descriptors 5, 8 and 9. IMAMO aims to increase the institutional capacity of the Bulgarian partners related to the monitoring and assessment of the Black Sea environment. The main outputs are: establishment of real time monitoring and set up of accredited laboratory facilities for marine waters and sediments chemical analysis to ensure the ability of Bulgarian partners to monitor progress of subsequent measures undertaken.

  12. Impact loads on the pressure vessel top

    International Nuclear Information System (INIS)

    Krieg, R.; Malmberg, T.; Messemer, G.

    1995-01-01

    A steam explosion can cause core melt to be bounced against the internal side of the RPV top. The bouncing velocity up to which the top can withstand the impact is to be determined. Plausible assumptions about a core melt mass of 80000 kg result in a tolerable maximum bouncing velocity of about 200 m/s. Reliable estimates are expected from the BERDA experiments simulating a pessimistic course of events on a 1:10 scale. (orig.)

  13. Search for single top production at HERA

    International Nuclear Information System (INIS)

    Brandt, G.

    2008-01-01

    A search for single top production in e p collisions using the complete high-energy data from HERA is presented. This search is based on the analysis of events containing isolated leptons (electronic or muons) and missing transverse momentum P T miss . In the absence of a signal, an upper limit on the top production cross-section σ ep→etX tuγ T miss and the measurements of W boson polarisation fractions.

  14. Search for the top quark with CDF

    International Nuclear Information System (INIS)

    Barbaro-Galtieri, A.

    1991-01-01

    During the 1988--89 Tevatron Collider run the CDF detector has collected data for an integrated luminosity of 4.4 pb -1 . The sample has been used to search for the top quark in several topologies. Preliminary results show that a top mass below 89 GeV is excluded at the 95% confidence level, thus extending the limit of 77 GeV previously published by CDF. 14 refs., 8 figs

  15. Single Top-Quark Production at CDF

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    The main challenge of the single top-quark search at the Tevatron is the huge background from W+jets events and QCD events, which makes the use of advanced multivariate techniques essential. The recent single top analyses using either the matrix element method, neural networks, likelihood discriminants or boosted decision trees as well as the combination of the former three analyses will be presented...

  16. Top Production Properties in ATLAS & CMS

    CERN Document Server

    Neep, Thomas James; The ATLAS collaboration

    2017-01-01

    The large mass and short lifetime of the top quark mean that it decays before forming bound states. This allows the top quark to be studied as a bare quark and opens up the possibility to measure many properties that can not be probed using other quarks. Precise study of these properties, including spin correlations, polarisations and asymmetries, may shed light on possible physics beyond the Standard Model.

  17. The discovery of the top quark

    International Nuclear Information System (INIS)

    Sinervo, P.K.

    1995-12-01

    The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the Τ resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark

  18. The Discovery of the Top Quark

    Science.gov (United States)

    Sinervo, P.K.

    1995-12-01

    The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.

  19. Anomalous couplings in single top and searches for rare top quark couplings with the ATLAS detector

    CERN Document Server

    Cabrera Urban, Susana; The ATLAS collaboration

    2017-01-01

    The top quark is the heaviest known fundamental particle and probing its couplings with the other fundamental particle may open a window to physics beyond the Standard Model. Single top-quark production provides a unique window to study the coupling between the top quark, the W boson and the b quark, since it involves the $Wtb$ vertex in both production and decay. Measurements of angular correlations in single top quark events in the t-channel exchange of a W boson are presented based on the 8 TeV ATLAS dataset. Differential cross-sections are measured as a function of angular variables that are sensitive to anomalous contributions to the Wtb vertex and the top quark polarization. Searches for flavour-changing neutral current top-quark interactions are also discussed based on the 8 TeV and 13 TeV ATLAS dataset. Searches for rare top quark decays to Higgs and Z bosons are presented in top quark production, and searches for rare top quark interactions with gluons and Z bosons are presented in single top quark p...

  20. Recent top physics results from CMS

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The top quark, discovered in 1995 at the Tevatron, is the heaviest known elementary particle. The largeness of its mass gives rise to a number of peculiar properties: top quarks decay before they would hadronize and the measurement of their decay products provides direct access to its properties such as spin, charge, or polarization. The top quark couples most strongly with the Higgs boson, and plays a key role in the electro-weak symmetry breaking and in many scenarios of physics beyond the Standard Model. With its large center-of-mass energy and luminosity, the LHC produces top quarks in copious quantities, giving access to many new precision measurements. In this seminar, I will present recent measurements from the CMS experiment. I will focus in particular on the results on single-top quark production, where results are available in all production modes, the t-, the s- and the tW-channels. Furthermore, I will present recent measurements of top quark properties as well as searches for anomalous couplings ...

  1. 5 CFR 1312.27 - Top secret control.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Top secret control. 1312.27 Section 1312... Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret... Top Secret material. The ATSCOs will be responsible for the accountability and custodianship of Top...

  2. Global change in the trophic functioning of marine food webs

    DEFF Research Database (Denmark)

    Maureaud, Aurore; Gascuel, Didier; Colléter, Mathieu

    2017-01-01

    and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI......The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches......) measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI) quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950...

  3. Prediction of top oil temperature for transformers

    Science.gov (United States)

    He, Qing

    2000-11-01

    When a transformer's winding gets too hot, either the load has to be reduced as a short-term solution or another transformer bay needs to be installed as a long-term plan. To decide on whether to deploy either of these two strategies, one should be able to predict the transformer temperature accurately. In this work, the traditional top-oil-rise model, top-oil model (which includes an ambient temperature) and semi-physical top-oil model are compared. The semi-physical top-oil model outperforms the other two models. Several attempts are also reported to improve the model used for top-oil temperature (TOT) prediction. It is shown that regardless of the order or complexity of the model, no model performs significantly better than the semi-physical top-oil model investigated; moreover, many models have performance measures that are approximately the same as the semi-physical model. Some of the sources of error that affect top-oil temperature prediction are studied here. Experimentation with various discretization schemes and models convinces the author that the semi-physical top-oil model used to predict transformer temperature is near optimal and that other sources of input-data error are frustrating the author's attempt to reduce the prediction error Further. The research demonstrates that the input error caused by database quantization, remote ambient temperature monitoring and low sampling rate accounts for about two-thirds of the error experienced with field data. The results of these simulations also show that the error caused by these sources is less than that obtained when using equivalent field data. It is the opinion of the author that most of this difference is due to the absence of significant driving variables, rather than the approximation used in constructing a semi-physical model. To further improve the error performance of the semi-physical top-oil model, three different neural network models including static neural network, temporal processing network

  4. Collaborative Research: Cloudiness transitions within shallow marine clouds near the Azores

    Energy Technology Data Exchange (ETDEWEB)

    Mechem, David B. [Univ. of Kansas, Lawrence, KS (United States). Atmospheric Science Program. Dept. of Geography and Atmospheric Science; de Szoeke, Simon P. [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Sciences; Yuter, Sandra E. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Marine, Earth, and Atmospheric Sciences

    2017-01-15

    Marine stratocumulus clouds are low, persistent, liquid phase clouds that cover large areas and play a significant role in moderating the climate by reflecting large quantities of incoming solar radiation. The deficiencies in simulating these clouds in global climate models are widely recognized. Much of the uncertainty arises from sub-grid scale variability in the cloud albedo that is not accurately parameterized in climate models. The Clouds, Aerosol and Precipitation in the Marine Boundary Layer (CAP–MBL) observational campaign and the ongoing ARM site measurements on Graciosa Island in the Azores aim to sample the Northeast Atlantic low cloud regime. These data represent, the longest continuous research quality cloud radar/lidar/radiometer/aerosol data set of open-ocean shallow marine clouds in existence. Data coverage from CAP–MBL and the series of cruises to the southeast Pacific culminating in VOCALS will both be of sufficient length to contrast the two low cloud regimes and explore the joint variability of clouds in response to several environmental factors implicated in cloudiness transitions. Our research seeks to better understand cloud system processes in an underexplored but climatologically important maritime region. Our primary goal is an improved physical understanding of low marine clouds on temporal scales of hours to days. It is well understood that aerosols, synoptic-scale forcing, surface fluxes, mesoscale dynamics, and cloud microphysics all play a role in cloudiness transitions. However, the relative importance of each mechanism as a function of different environmental conditions is unknown. To better understand cloud forcing and response, we are documenting the joint variability of observed environmental factors and associated cloud characteristics. In order to narrow the realm of likely parameter ranges, we assess the relative importance of parameter conditions based primarily on two criteria: how often the condition occurs (frequency

  5. Understanding the drivers of marine liquid-water cloud occurrence and properties with global observations using neural networks

    Directory of Open Access Journals (Sweden)

    H. Andersen

    2017-08-01

    Full Text Available The role of aerosols, clouds and their interactions with radiation remain among the largest unknowns in the climate system. Even though the processes involved are complex, aerosol–cloud interactions are often analyzed by means of bivariate relationships. In this study, 15 years (2001–2015 of monthly satellite-retrieved near-global aerosol products are combined with reanalysis data of various meteorological parameters to predict satellite-derived marine liquid-water cloud occurrence and properties by means of region-specific artificial neural networks. The statistical models used are shown to be capable of predicting clouds, especially in regions of high cloud variability. On this monthly scale, lower-tropospheric stability is shown to be the main determinant of cloud fraction and droplet size, especially in stratocumulus regions, while boundary layer height controls the liquid-water amount and thus the optical thickness of clouds. While aerosols show the expected impact on clouds, at this scale they are less relevant than some meteorological factors. Global patterns of the derived sensitivities point to regional characteristics of aerosol and cloud processes.

  6. Lagrangian evolution of the marine boundary layer from the Cloud System Evolution in the Trades (CSET) campaign

    Science.gov (United States)

    Mohrmann, J.; Ghate, V. P.; McCoy, I. L.; Bretherton, C. S.; Wood, R.; Minnis, P.; Palikonda, R.

    2017-12-01

    The Cloud System Evolution in the Trades (CSET) field campaign took place July/August 2015 to study the evolution of clouds, precipitation, and aerosols in the stratocumulus-to-cumulus (Sc-Cu) transition region of the northeast Pacific marine boundary layer (MBL). Aircraft observations sampled across a wide range of cloud and aerosol conditions. The sampling strategy, where MBL airmasses were sampled with the NSF/NCAR Gulfstream-V (HIAPER) and resampled then at their advected location two days later, resulted in a dataset of 14 paired flights suitable for Lagrangian analysis. This analysis shows that Lagrangian coherence of long-lived species (namely CO and O3) across 48 hours are high, but that of subcloud aerosol, MBL depth, and cloud properties is limited. Geostationary satellite retrievals are compared against aircraft observations; these are combined with reanalysis data and HYSPLIT trajectories to document the Lagrangian evolution of cloud fraction, cloud droplet number concentration, liquid water path, estimated inversion strength (EIS), and MBL depth, which are used to expand upon and validate the aircraft-based analysis. Many of the trajectories sampled by the aircraft show a clear Sc-Cu transition. Although satellite cloud fraction and EIS were found to be strongly spatiotemporally correlated, changes in MBL cloud fraction along trajectories did not correlate with any measure of EIS forcing.

  7. Top-philic scalar Dark Matter with a vector-like fermionic top partner

    OpenAIRE

    Baek, Seungwon; Ko, Pyungwon; Wu, Peiwen

    2016-01-01

    We consider a simple extension of the Standard Model with a scalar top-philic Dark Matter (DM) $S$ coupling, apart from the Higgs portal, exclusively to the right-handed top quark $t_R$ and a colored vector-like top partner $T$ with a Yukawa coupling $y_{ST}$ which we call the topVL portal. When the Higgs portal is closed and $y_{ST}$ is perturbative $ (\\lesssim 1)$, $TS\\to (W^+b, gt)$, $SS\\to t\\bar{t}$ and $T\\bar{T}\\to (q\\bar{q},gg)$ provide the dominant (co)annihilation contributions to obt...

  8. Bioprospecting Marine Plankton

    Directory of Open Access Journals (Sweden)

    Chris Bowler

    2013-11-01

    Full Text Available The ocean dominates the surface of our planet and plays a major role in regulating the biosphere. For example, the microscopic photosynthetic organisms living within provide 50% of the oxygen we breathe, and much of our food and mineral resources are extracted from the ocean. In a time of ecological crisis and major changes in our society, it is essential to turn our attention towards the sea to find additional solutions for a sustainable future. Remarkably, while we are overexploiting many marine resources, particularly the fisheries, the planktonic compartment composed of zooplankton, phytoplankton, bacteria and viruses, represents 95% of marine biomass and yet the extent of its diversity remains largely unknown and underexploited. Consequently, the potential of plankton as a bioresource for humanity is largely untapped. Due to their diverse evolutionary backgrounds, planktonic organisms offer immense opportunities: new resources for medicine, cosmetics and food, renewable energy, and long-term solutions to mitigate climate change. Research programs aiming to exploit culture collections of marine micro-organisms as well as to prospect the huge resources of marine planktonic biodiversity in the oceans are now underway, and several bioactive extracts and purified compounds have already been identified. This review will survey and assess the current state-of-the-art and will propose methodologies to better exploit the potential of marine plankton for drug discovery and for dermocosmetics.

  9. Single top quarks and dark matter

    Science.gov (United States)

    Pinna, Deborah; Zucchetta, Alberto; Buckley, Matthew R.; Canelli, Florencia

    2017-08-01

    Processes with dark matter interacting with the standard model fermions through new scalars or pseudoscalars with flavor-diagonal couplings proportional to fermion mass are well motivated theoretically, and provide a useful phenomenological model with which to interpret experimental results. Two modes of dark matter production from these models have been considered in the existing literature: pairs of dark matter produced through top quark loops with an associated monojet in the event, and pair production of dark matter with pairs of heavy flavored quarks (tops or bottoms). In this paper, we demonstrate that a third, previously overlooked channel yields a non-negligible contribution to LHC dark matter searches in these models. In spite of a generally lower production cross section at LHC when compared to the associated top-pair channel, non-flavor violating single top quark processes are kinematically favored and can significantly increase the sensitivity to these models. Including dark matter production in association with a single top quark through scalar or pseudoscalar mediators, the exclusion limit set by the LHC searches for dark matter can be improved by 30% up to a factor of two, depending on the mass assumed for the mediator particle.

  10. Monotop signature from a fermionic top partner

    Science.gov (United States)

    Gonçalves, Dorival; Kong, Kyoungchul; Sakurai, Kazuki; Takeuchi, Michihisa

    2018-01-01

    We investigate monotop signatures arising from phenomenological models of fermionic top partners, which are degenerate in mass and decay into a bosonic dark matter candidate, either spin 0 or spin 1. Such a model provides a monotop signature as a smoking gun, while conventional searches with t t ¯ + missing transverse momentum are limited. Two such scenarios, (i) a phenomenological third generation extradimensional model with excited top and electroweak sectors, and (ii) a model where only a top partner and a dark matter particle are added to the standard model, are studied in the degenerate mass regime. We find that in the case of extra dimension a number of different processes give rise to effectively the same monotop final state, and a great gain can be obtained in the sensitivity for this channel. We show that the monotop search can explore top-partner masses up to 630 and 300 GeV for the third generation extradimensional model and the minimal fermionic top-partner model, respectively, at the high luminosity LHC.

  11. Top physics at CLIC and ILC

    CERN Document Server

    AUTHOR|(SzGeCERN)442572

    2016-11-11

    Measurements of top quark production at $e^+e^-$ colliders can provide a leap in precision in our knowledge of top quark properties and open a new window on physics beyond the Standard Model. In this contribution the top quark physics prospects of linear colliders is reviewed. Progress in detailed full-simulation studies is reported for the highlights of the program. We present the prospects for a measurement of the top quark mass and width in a scan of the beam energy through the pair production threshold, and discuss new studies of alternative measurements in continuum production, which are also capable of a precise determination of the mass in a rigorously defined mass scheme. A precision of 50 MeV on the $\\overline{MS}$ mass is expected when taking into account the dominant systematic uncertainties. Another key measurement is the study of the top quark couplings to electroweak gauge bosons, where form factors can be determined to 1% precision, an order of magnitude better than those from the full LHC prog...

  12. The marine diversity spectrum

    DEFF Research Database (Denmark)

    Reuman, Daniel C.; Gislason, Henrik; Barnes, Carolyn

    2014-01-01

    of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts...... the form of the diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum...... is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0 center dot 5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0 center...

  13. Marine biodiversity in Colombia

    International Nuclear Information System (INIS)

    Diaz, Juan Manuel

    2002-01-01

    One decade ago, the seas and oceans were considered biologically less diverse that the terrestrial environment. Now it is known that it is on the contrary; 33 of the 34 categories of animals (phylum), they are represented in the sea, compared with those solely 15 that exist in earth. The investigation about the diversity of life in the sea has been relatively scorned, but there are big benefits that we can wait if this is protected. The captures of fish depend on it; the species captured by the fisheries are sustained of the biodiversity of their trophic chains and habitats. The marine species are probably the biggest reservoir of chemical substances that can be used in pharmaceutical products. The genetic material of some species can be useful in biotechnical applications. The paper treats topics like the current state of the knowledge in marine biodiversity and it is done a diagnostic of the marine biodiversity in Colombia

  14. Marine biosurfaces research program

    Science.gov (United States)

    The Office of Naval Research (ONR) of the U.S. Navy is starting a basic research program to address the initial events that control colonization of surfaces by organisms in marine environments. The program “arises from the Navy's need to understand and ultimately control biofouling and biocorrosion in marine environments,” according to a Navy announcement.The program, “Biological Processes Controlling Surface Modification in the Marine Environment,” will emphasize the application of in situ techniques and modern molecular biological, biochemical, and biophysical approaches; it will also encourage the development of interdisciplinary projects. Specific areas of interest include sensing and response to environmental surface (physiology/physical chemistry), factors controlling movement to and retention at surfaces (behavior/hydrodynamics), genetic regulation of attachment (molecular genetics), and mechanisms of attachment (biochemistry/surface chemistry).

  15. Marine-Design Education

    DEFF Research Database (Denmark)

    Andersen, Poul; Birmingham, R.; Sortland, B.

    2006-01-01

    This report addresses Marine-Design Education in view of present and forecasted demands of the maritime industry, determined by a drastically transforming economic and technological maritime environment. In this framework, this report discusses in depth IT-based Marine Design education (par. 4......) and reveals innovative educational concepts and initiatives, such as the EiT (Experts in a Team) concept (par. 3), the SFS (Student Friendly Software) initiative (par. 5), Education Driven Research (EDR, par. 6) and Research Based Education (RBE, par. 6). Nevertheless, the paper stresses the need...... for continuity between traditional and modern ways of teaching (par. 4) and points out that Marine Design education is not only about Design, but should also address project/business administration and decision making issues (par. 7)....

  16. D-Zero top quark mass analysis

    International Nuclear Information System (INIS)

    Strovink, M.

    1996-10-01

    I report on D null's preliminary analyses of the top quark mass m t based on an exposure at √s = 1.8 TeV with integrated luminosity ∼100 pb -1 at the Fermilab Tevatron p anti p collider. From three e + μ + ≥ 2 jet events (with background 0.36 ± 0.09), using partly original methods, we obtain m t = 158 ± 24(stat) ± 10(syst) GeV/c 2 . From 30 e or μ + ±4 jets events (with background 17.4 ±2.2), we find m t = 170 ± 15(stat) ± 10(syst) GeV/c 2 . Recently, using multivariate methods based on particular kinematic variables, we have learned how to improve the background suppression in the latter sample without unduly distorting the reconstructed top mass spectra. Applying these methods should improve considerably the accuracy of our top quark mass determination

  17. Workshop: Waiting for the top quark

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The world of elementary particle physics is eagerly waiting for the top quark, probably the final element of the 'periodic table' of elementary particle constituents. This table consists of two families of weakly interacting particles (leptons) - one series carrying electric charge; the other being electrically neutral - together with a family of quarks carrying electric charge 2/3 (up, charm, top) and a family of charge -1/3 quarks (down, strange, beauty). It was then not surprising that the 1990 Theory Workshop at the DESY Laboratory in Hamburg in October, devoted this time to 'top physics', attracted some 200 physicists, substantially more than previous workshops in the series

  18. Top quark physics in ATLAS (CORFU 2014)

    CERN Document Server

    Moreno Llácer, M; The ATLAS collaboration

    2014-01-01

    The top quark is the heaviest elementary particle observed to date. Being heavier than a W boson, it is the only quark that decays weakly, i.e. into a real W boson and a b quark, before hadronization can occur. In addition, it is the only quark whose Yukawa coupling to the Higgs boson is order of unity. For these reasons the top quark plays a special role in the Standard Model of Particle Physics and in many of its extensions. An accurate knowledge of its properties (mass, couplings, production cross section, decay branching ratios, etc.) can bring key information on fundamental interactions at the electroweak breaking scale and beyond. In this talk the latest measurements of the characteristics of the top quark carried out in the ATLAS experiment at the Large Hadron Collider are presented.

  19. Anomalous creation and decay of top quarks

    CERN Document Server

    Hasegawa, S; The ATLAS collaboration

    2012-01-01

    Due to the top quark’s mass of 173.5 GeV/c2 which is around the energy scale of the spon- taneous symmetry breaking, appearance of new physics can be expected in its production and decay as an anomaly from the standard model expectation. The ATLAS and the CMS experiments have accumulated about 5 fb−1 of data of proton-proton collisions with 7 TeV center of mass energy in 2011, in which 800,000 top quarks pairs are expected. With this high statistics, the ATLAS and the CMS collaborations have investigated the top quark’s production and decay precisely and have reported the results consistent with the standard model.

  20. Events Calendar: Smithsonian Marine Ecosystems Exhibit: Smithsonian Marine

    Science.gov (United States)

    current Smithsonian research on the plants and animals of the Indian River Lagoon and marine environments Station (SMS) at Fort Pierce Smithsonian Marine Station at Fort Pierce Website Search Box History Modeling Ecosystems Virtual Tour Facebook Instagram Twitter SMS Home › Smithsonian Marine

  1. New Waves in Marine Science Symposium: Marine Animal Communication.

    Science.gov (United States)

    Allen, Betty, Comp.

    1989-01-01

    Presented are the abstracts from three research projects on marine social systems which were a part of a marine science symposium. Five sets of activities on marine animal communication are included, one each for grades K-2, 3-5, 6-8 and 9-12, and informal education. (CW)

  2. 75 FR 19670 - Marine Highway Projects

    Science.gov (United States)

    2010-04-15

    ... DEPARTMENT OF TRANSPORTATION Maritime Administration Marine Highway Projects ACTION: Solicitation of applications for Marine highway projects. SUMMARY: The Department of Transportation is soliciting applications for Marine Highway Projects as specified in the America's Marine Highway Program Final Rule, MARAD...

  3. The biology of marine plants

    National Research Council Canada - National Science Library

    Dring, M.J

    1982-01-01

    Since over 90% of the species of marine plants are algae, most of the book is devoted to the marine representatives of this group, with examples from all oceans and coasts of the world where detailed work has been done...

  4. Antifouling Compounds from Marine Invertebrates.

    Science.gov (United States)

    Qi, Shu-Hua; Ma, Xuan

    2017-08-28

    In this review, a comprehensive overview about the antifouling compounds from marine invertebrates is described. In total, more than 198 antifouling compounds have been obtained from marine invertebrates, specifically, sponges, gorgonian and soft corals.

  5. Antifouling Compounds from Marine Invertebrates

    OpenAIRE

    Qi, Shu-Hua; Ma, Xuan

    2017-01-01

    In this review, a comprehensive overview about the antifouling compounds from marine invertebrates is described. In total, more than 198 antifouling compounds have been obtained from marine invertebrates, specifically, sponges, gorgonian and soft corals.

  6. The Danish Marine Monitoring System

    DEFF Research Database (Denmark)

    Ærtebjerg, G.

    1997-01-01

    Indeholder abstracts fra Workshop on Marine Monitoring Systems and Technology, Risø, 17-18 April 1996.......Indeholder abstracts fra Workshop on Marine Monitoring Systems and Technology, Risø, 17-18 April 1996....

  7. 76 FR 25308 - Marine Mammals

    Science.gov (United States)

    2011-05-04

    ...-XA165 Marine Mammals AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Jennifer Burns, Ph.D., University of Alaska Anchorage, Biology Department, 3101 Science Circle, Anchorage, AK, has been issued a permit to conduct [[Page 25309

  8. Optimal Taxation, Inequality and Top Incomes

    OpenAIRE

    Andrienko, Yuri; Apps, Patricia; Rees, Ray

    2014-01-01

    In a number of high-income countries over the past few decades there has been a large growth in income inequality and at the same time a shift in the burden of taxation from the top to the middle of the income distribution. This paper applies the theory of optimal piecewise linear taxation to the issue of the taxation of top incomes. Our results suggest that an appropriate response to rising inequality is a shift towards a more progressive multi-bracket income tax system, with a more differen...

  9. Boosted top production in ATLAS and CMS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00237277; The ATLAS collaboration

    2017-01-01

    An overview of the boosted top production analyses using data collected by the ATLAS and CMS experiments at $\\sqrt{s}=$' 8 TeV and 13 TeV of proton-proton collisions at the LHC is presented. These analyses use techniques for the reconstruction of boosted objects to measure the production of top quarks at high transverse momenta. The measurements are optimized for the different final states and for different ranges of the transverse momenta of the particles involved, improving on measurements with traditional objects reconstruction based on the combination of resolved objects.

  10. New multigrid solver advances in TOPS

    International Nuclear Information System (INIS)

    Falgout, R D; Brannick, J; Brezina, M; Manteuffel, T; McCormick, S

    2005-01-01

    In this paper, we highlight new multigrid solver advances in the Terascale Optimal PDE Simulations (TOPS) project in the Scientific Discovery Through Advanced Computing (SciDAC) program. We discuss two new algebraic multigrid (AMG) developments in TOPS: the adaptive smoothed aggregation method (αSA) and a coarse-grid selection algorithm based on compatible relaxation (CR). The αSA method is showing promising results in initial studies for Quantum Chromodynamics (QCD) applications. The CR method has the potential to greatly improve the applicability of AMG

  11. TOP500 Supercomputers for November 2003

    Energy Technology Data Exchange (ETDEWEB)

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2003-11-16

    22nd Edition of TOP500 List of World s Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 22nd edition of the TOP500 list of the worlds fastest supercomputers was released today (November 16, 2003). The Earth Simulator supercomputer retains the number one position with its Linpack benchmark performance of 35.86 Tflop/s (''teraflops'' or trillions of calculations per second). It was built by NEC and installed last year at the Earth Simulator Center in Yokohama, Japan.

  12. Understanding microelectronics a top-down approach

    CERN Document Server

    Maloberti, Franco

    2011-01-01

    The microelectronics evolution has given rise to many modern benefits but has also changed design methods and attitudes to learning. Technology advancements shifted focus from simple circuits to complex systems with major attention to high-level descriptions. The design methods moved from a bottom-up to a top-down approach. For today's students, the most beneficial approach to learning is this top-down method that demonstrates a global view of electronics before going into specifics. Franco Maloberti uses this approach to explain the fundamentals of electronics, such as processing functions,

  13. W/Top/Higgs-tagging in ATLAS

    CERN Document Server

    Norjoharuddeen, Nurfikri; The ATLAS collaboration

    2017-01-01

    We present updates of W, Top and Higgs tagging studies with the ATLAS detector. The performance of 2 variable taggers, HEPTopTagger and shower deconstruction are compared in Monte Carlo simulations. To asses the modelling of the taggers’ performance, the tagging efficiencies are measured, with the full 2015+2016 dataset, in semi-leptonic top quark pair events and the background rejections are measured in dijet and photon+jet topologies. Recent developments in subjet reconstruction techniques for high transverse momentum Higgs->bb tagging are also presented.

  14. TopN-Pareto Front Search

    Energy Technology Data Exchange (ETDEWEB)

    2016-12-21

    The JMP Add-In TopN-PFS provides an automated tool for finding layered Pareto front to identify the top N solutions from an enumerated list of candidates subject to optimizing multiple criteria. The approach constructs the N layers of Pareto fronts, and then provides a suite of graphical tools to explore the alternatives based on different prioritizations of the criteria. The tool is designed to provide a set of alternatives from which the decision-maker can select the best option for their study goals.

  15. Recent Results on Top Physics in CMS

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Top physics is a pillar of the physics programme at the LHC. It involves precision measurements, leading to constraints on standard model parameters, as well as many measurements of observables sensitive to new physics. In this seminar, an overview of measurements performed by the CMS experiment in the domain of top physics will be presented, based on pp data collected in 2011 at a center-of-mass energy of 7 TeV. The results will be compared to expectations from theory. Emphasis in will be given to more recent results and to the treatment of systematic uncertainties.

  16. Top and Electroweak Measurements at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bartos, P. [Comenius U.

    2016-01-01

    In this report, we summarize the latest results of the top-quark mass and electroweak measurements from the Tevatron. Since the world combination of top-quark mass measurements was done, CDF and D0 experiments improved the precision of several results. Some of them reach the relative precition below 1% for a single measurement. From the electroweak results, we report on the WW and WZ production cross section, measurements of the weak mixing angle and indirect measurements of W boson mass. The Tevatron results of the weak mixing angle are still the most precise ones of hadron colliders.

  17. Single top quark production at LEP200?

    International Nuclear Information System (INIS)

    Boos, E.; Ishikawa, T.; Kaneko, T.; Kawabata, S.; Kurihara, Y.; Shimizu, Y.; Tanaka, H.

    1994-01-01

    A complete tree-level calculation of the reaction e + e - → e + ν e anti tb (e - anti ν e t anti b) in the electroweak standard theory in the LEP200 energy range is presented. For top quark masses in the range 130 to 190 GeV the cross sections are found to be in the order of 10 -5 to 10 -6 pb. Therefore, the number of single top quark events is expected to be negligible even with an integrated luminosity of L = 500 pb -1 . It is further demonstrated that the Weizsaecker-Williams approximation is approaching the accurate cross section calculations resonably well. (orig.)

  18. Lepton distribution in top decay: A probe of new physics and top ...

    Indian Academy of Sciences (India)

    it may become difficult to probe new physics couplings of top quark. However, if one can construct observables that are sensitive to production and decay mecha- nism independent of each other, the analysis can be greatly simplified. It has been shown that the angular distribution of the leptons from the decay of top quark is.

  19. An Efficiency Comparison of MBA Programs: Top 10 versus Non-Top 10

    Science.gov (United States)

    Hsu, Maxwell K.; James, Marcia L.; Chao, Gary H.

    2009-01-01

    The authors compared the cohort group of the top-10 MBA programs in the United States with their lower-ranking counterparts on their value-added efficiency. The findings reveal that the top-10 MBA programs in the United States are associated with statistically higher average "technical and scale efficiency" and "scale efficiency", but not with a…

  20. Determination of the top-quark mass from hadro-production of single top-quarks

    International Nuclear Information System (INIS)

    Alekhin, S.; Moch, S.; Thier, S.

    2016-08-01

    We present a new determination of the top-quark mass m_t based on the experimental data from the Tevatron and the LHC for single-top hadro-production. We use the inclusive cross sections of s- and t-channel top-quark production to extract m_t and to minimize the dependence on the strong coupling constant and the gluon distribution in the proton compared to the hadro-production of top-quark pairs. As part of our analysis we compute the next-to-next-to-leading order approximation for the s-channel cross section in perturbative QCD based on the known soft-gluon corrections and implement it in the program HatHor for the numerical evaluation of the hadronic cross section. Results for the top-quark mass are reported in the MS and in the on-shell renormalization scheme.

  1. Identifying Sources of Marine Litter

    OpenAIRE

    VEIGA Joana Mira; FLEET David; KINSEY Sue; NILSSON Per; VLACHOGIANNI Thomais; WERNER Stefanie; GALGANI Francois; THOMPSON Richard; DAGEVOS Jeroen; GAGO Jesus; SOBRAL Paula; CRONIN Richard

    2016-01-01

    Marine litter is a global problem causing harm to marine wildlife, coastal communities and maritime activities. It also embodies an emerging concern for human health and safety. The reduction of marine litter pollution poses a complex challenge for humankind, requiring adjustments in human behaviour as well as in the different phases of the life-cycle of products and across multiple economic sectors. The Marine Strategy Framework Directive (MSFD) requires European Member States to monitor...

  2. Global change in the trophic functioning of marine food webs.

    Directory of Open Access Journals (Sweden)

    Aurore Maureaud

    Full Text Available The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950-2010 time-periods. Global trends were identified and cluster analyses were used to characterize the variability of trends between ecosystems. Results showed that the most common pattern over the study period is a global decrease in TCI, while the ECI indicator tends to increase. Thus, changes in species assemblages would induce faster and apparently more efficient biomass transfers in marine food webs. Results also suggested that the main driver of change over that period had been the large increase in fishing pressure. The largest changes occurred in ecosystems where 'fishing down the marine food web' are most intensive.

  3. Oceanic processes in marine pollution

    International Nuclear Information System (INIS)

    Baumgartner, D.J.; Duedall, I.W.

    1990-01-01

    This book covers the following areas: bioaccumulation of Polycyclic Aromatic hydrocarbons in marine environments; behavior of drilling fluid discharges off the coast of California; effects of drilling fluids on marine organisms; and the effects of radioactive waste disposal on marine amphipods

  4. Marine Renewable Energies

    DEFF Research Database (Denmark)

    Azzellino, Arianna; Conley, Daniel; Vicinanza, Diego

    2013-01-01

    Countries with coastlines may have valuable renewable energy resources in the form of tides, currents, waves, and offshorewind.The potential to gather energy from the sea has recently gained interest in several nations, so Marine Renewable Energy Installations (hereinafter MREIs) will likely become...

  5. Marine and Estuarine Pollution.

    Science.gov (United States)

    Reish, Donald J.

    1978-01-01

    Presents a literature review of the effects of various pollutants on marine and estuarine organisms, covering publications of 1976-77. This review includes: (1) effects of pesticides, dredging, dumping, sludge, and petroleum hydrocarbons; and (2) diseases and tissue abnormalities. A list of 441 references is also presented. (HM)

  6. NWS Marine Forecast Areas

    Science.gov (United States)

    of Commerce Ocean Prediction Center National Oceanic and Atmospheric Administration Analysis & Unified Surface Analysis Ocean Ocean Products Ice & Icebergs NIC Ice Products NAIS Iceberg Analysis Social Media Facebook Twitter YouTube Search Search For Go NWS All NOAA NWS Marine Forecast Areas

  7. Marine fungi: A critique

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, S.; Raghukumar, C.

    in the sea have been ignored to a large extent. However, several instances of terrestrial species of fungi, active in marine environment have been reported. The arguments to support the view that terrestrial species of fungi by virtue of their physiological...

  8. Marine complex adaptive systems

    NARCIS (Netherlands)

    Bigagli, Emanuele

    2017-01-01

    Anthropogenic and climate-related stressors challenge the health of nearly every part of the global oceans. They affect the capacity of oceans to regulate global weather and climate, as well as ocean productivity and food services, and result in the loss or degradation of marine habitats and

  9. Marine biogeography and evolution : Diversity patterns of planktonic gastropods and amphipods

    NARCIS (Netherlands)

    Burridge, A.K.

    2017-01-01

    Current changes in the oceans, including global warming and ocean acidification, are partially caused by human activity, unlike earlier episodes of change throughout geological history. Understanding and forecasting the responses of marine organisms to these changes is top priority for scientists,

  10. Latitudinal range influences the seasonal variation in the foraging behavior of marine top predators.

    Directory of Open Access Journals (Sweden)

    Stella Villegas-Amtmann

    Full Text Available Non-migratory resident species should be capable of modifying their foraging behavior to accommodate changes in prey abundance and availability associated with a changing environment. Populations that are better adapted to change will have higher foraging success and greater potential for survival in the face of climate change. We studied two species of resident central place foragers from temperate and equatorial regions with differing population trends and prey availability associated to season, the California sea lion (Zalophus californianus (CSL whose population is increasing and the endangered Galapagos sea lion (Zalophus wollebaeki (GSL whose population is declining. To determine their response to environmental change, we studied and compared their diving behavior using time-depth recorders and satellite location tags and their diet by measuring C and N isotope ratios during a warm and a cold season. Based on latitudinal differences in oceanographic productivity, we hypothesized that the seasonal variation in foraging behavior would differ for these two species. CSL exhibited greater seasonal variability in their foraging behavior as seen in changes to their diving behavior, foraging areas and diet between seasons. Conversely, GSL did not change their diving behavior between seasons, presenting three foraging strategies (shallow, deep and bottom divers during both. GSL exhibited greater dive and foraging effort than CSL. We suggest that during the warm and less productive season a greater range of foraging behaviors in CSL was associated with greater competition for prey, which relaxed during the cold season when resource availability was greater. GSL foraging specialization suggests that resources are limited throughout the year due to lower primary production and lower seasonal variation in productivity compared to CSL. These latitudinal differences influence their foraging success, pup survival and population growth reflected in contrasting population trends in which CSL are more successful and potentially more resilient to climate change.

  11. Biodiversity mediates top-down control in eelgrass ecosystems: a global comparative-experimental approach.

    Science.gov (United States)

    Duffy, J Emmett; Reynolds, Pamela L; Boström, Christoffer; Coyer, James A; Cusson, Mathieu; Donadi, Serena; Douglass, James G; Eklöf, Johan S; Engelen, Aschwin H; Eriksson, Britas Klemens; Fredriksen, Stein; Gamfeldt, Lars; Gustafsson, Camilla; Hoarau, Galice; Hori, Masakazu; Hovel, Kevin; Iken, Katrin; Lefcheck, Jonathan S; Moksnes, Per-Olav; Nakaoka, Masahiro; O'Connor, Mary I; Olsen, Jeanine L; Richardson, J Paul; Ruesink, Jennifer L; Sotka, Erik E; Thormar, Jonas; Whalen, Matthew A; Stachowicz, John J

    2015-07-01

    Nutrient pollution and reduced grazing each can stimulate algal blooms as shown by numerous experiments. But because experiments rarely incorporate natural variation in environmental factors and biodiversity, conditions determining the relative strength of bottom-up and top-down forcing remain unresolved. We factorially added nutrients and reduced grazing at 15 sites across the range of the marine foundation species eelgrass (Zostera marina) to quantify how top-down and bottom-up control interact with natural gradients in biodiversity and environmental forcing. Experiments confirmed modest top-down control of algae, whereas fertilisation had no general effect. Unexpectedly, grazer and algal biomass were better predicted by cross-site variation in grazer and eelgrass diversity than by global environmental gradients. Moreover, these large-scale patterns corresponded strikingly with prior small-scale experiments. Our results link global and local evidence that biodiversity and top-down control strongly influence functioning of threatened seagrass ecosystems, and suggest that biodiversity is comparably important to global change stressors. © 2015 John Wiley & Sons Ltd/CNRS.

  12. Marine Fish Hybridization

    KAUST Repository

    He, Song

    2017-04-01

    Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

  13. Model uncertainties in top-quark physics

    CERN Document Server

    Seidel, Markus

    2014-01-01

    The ATLAS and CMS collaborations at the Large Hadron Collider (LHC) are studying the top quark in pp collisions at 7 and 8 TeV. Due to the large integrated luminosity, precision measurements of production cross-sections and properties are often limited by systematic uncertainties. An overview of the modeling uncertainties for simulated events is given in this report.

  14. Learning from Top-Performing Managers.

    Science.gov (United States)

    Brown, Paul L.

    2000-01-01

    Illustrates five criteria that can be used to identify the "best" managers in any organization: business results, employee attitudes, peer confirmation, upper-level manager appraisal, and customer satisfaction. Examines what top-performing managers say and do, and concludes that their thinking processes and their specific sets of skills…

  15. Taking a gamble on the top quark

    International Nuclear Information System (INIS)

    Flam, F.

    1994-01-01

    This article describes the possible discovery of the top quark at Fermilab. Evidence for its existence is now at the level of two standard deviations above background, but a solid claim for discovery will not be made until the probability is five standard deviations. That should require one more year of experimentation

  16. New Physics with Energetic Top Quarks

    CERN Document Server

    Andeen, Timothy; The ATLAS collaboration

    2018-01-01

    Many theories beyond the Standard Model predict new phenomena which decay to energetic top quarks. Searches for such new physics models are performed using the ATLAS experiment at the LHC using proton-proton collision data collected in 2015 and 2016 with a center-of-mass energy of 13 TeV. Selected recent results will be discussed.

  17. Top-Ten IT Issues: 2009

    Science.gov (United States)

    Agee, Anne Scrivener; Yang, Catherine

    2009-01-01

    This article presents the top-ten IT-related issues in terms of strategic importance to the institution, as revealed by the tenth annual EDUCAUSE Current Issues Survey. These IT-related issues include: (1) Funding IT; (2) Administrative/ERP Information Systems; (3) Security; (4) Infrastructure/Cyberinfrastructure; (5) Teaching and Learning with…

  18. Top-down modulation, emotion, and hallucination

    NARCIS (Netherlands)

    Aleman, A; Kahn, RS

    2002-01-01

    We argue that the pivotal role assigned by Northoff to the principle of top-down modulation in catatonia might successfully be applied to other symptoms of schizophrenia, for example, hallucinations. Second, we propose that Northoffs account would benefit from a more comprehensive analysis of the

  19. Top Down proteomics: Facts and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Catherman, Adam D.; Skinner, Owen S.; Kelleher, Neil L., E-mail: n-kelleher@northwestern.edu

    2014-03-21

    Highlights: • Top Down versus Bottom Up proteomics analysis. • Separations methods for Top Down proteomics. • Developments in mass spectrometry instrumentation and fragmentation. • Native mass spectrometry. - Abstract: The rise of the “Top Down” method in the field of mass spectrometry-based proteomics has ushered in a new age of promise and challenge for the characterization and identification of proteins. Injecting intact proteins into the mass spectrometer allows for better characterization of post-translational modifications and avoids several of the serious “inference” problems associated with peptide-based proteomics. However, successful implementation of a Top Down approach to endogenous or other biologically relevant samples often requires the use of one or more forms of separation prior to mass spectrometric analysis, which have only begun to mature for whole protein MS. Recent advances in instrumentation have been used in conjunction with new ion fragmentation using photons and electrons that allow for better (and often complete) protein characterization on cases simply not tractable even just a few years ago. Finally, the use of native electrospray mass spectrometry has shown great promise for the identification and characterization of whole protein complexes in the 100 kDa to 1 MDa regime, with prospects for complete compositional analysis for endogenous protein assemblies a viable goal over the coming few years.

  20. Measuring the running top-quark mass

    International Nuclear Information System (INIS)

    Langenfeld, Ulrich; Uwer, Peter

    2010-06-01

    In this contribution we discuss conceptual issues of current mass measurements performed at the Tevatron. In addition we propose an alternative method which is theoretically much cleaner and to a large extend free from the problems encountered in current measurements. In detail we discuss the direct determination of the top-quark's running mass from the cross section measurements performed at the Tevatron. (orig.)

  1. Top management motivation in global corporations

    Directory of Open Access Journals (Sweden)

    Dmytro Lukianenko

    2015-11-01

    Full Text Available The article explores economic localization, socialization and development intellectualization processes. The research is focused on the relevant problem implying formation and development of human resources at organizations as a key factor of their competitiveness. Based on generalizing modern theoretical motivational models a comprehensive analysis of the motivation system for top management of corporations within the paradigm of global management has been carried out. Special attention is paid to the phenomenon of global business personification and virtualization, as well as to the formation of new financial and nonfinancial incentives for top managers. Practices of effective incentives for the contemporary key corporate management actors have been studied. A comprehensive country-based comparative analysis of key tools for financial and non-financial corporate incentives for top managers within the system of long-term, short-term and regulatory criteria and parameters has been performed. Based on summarizing academic studies and empirical evidence of the leading multinational corporations a motivational model for top management of corporations has been grounded and suggested for practical implementation in Ukraine with the said model accounting for the corporations' basic needs, financial status and interests as well as for countryspecific and regional features.

  2. Essays on top management and corporate behavior

    NARCIS (Netherlands)

    Wu, H.T.

    2010-01-01

    Human behavior is fascinating, and there is no exception to what its influences are on the financial market. This dissertation consists of three essays that examine corporate behavior that is affected by decisions made by the top management. The first essay studies the rationale for leveraged buyout

  3. Are Female Top Managers Really Paid Less?

    NARCIS (Netherlands)

    Geiler, P.H.M.; Renneboog, L.D.R.

    2014-01-01

    Abstract: Are female top managers paid less than their male counterparts? Is the gender gap higher in male-dominated industries? What effect on pay do female non-executive directors and remuneration consultants exert? While we find no pay gap for the figure-head (CEO), there is strong pay

  4. Are female top managers really paid less?

    NARCIS (Netherlands)

    Geiler, P.H.M.; Renneboog, Luc

    2015-01-01

    We study the gender pay gap for all top managers (CEO and executive directors) of listed UK companies and find mixed evidence: female CEOs do not face a pay gap, but the other female executive directors (e.g. CFO, COO, Deputy CEO) are discriminated against (while controlling for position, tenure,

  5. Table-top diffuse optical imaging

    NARCIS (Netherlands)

    Sturgeon, K.A.; Bakker, L.P.

    2006-01-01

    This report describes the work done during a six months internshipat Philips Research for a Masters in Electronic and Electrical Engineering. An existing table-top tomography system for measuring lightin phantom breasts was restored. Updated software control and image reconstruction software was

  6. Top Tagging by Deep Learning Algorithm

    CERN Document Server

    Akil, Ali

    2015-01-01

    In this report I will show the application of a deep learning algorithm on a Monte Carlo simulation sample to test its performance in tagging hadronic decays of boosted top quarks and compare what we get with the results of the application of some other algorithms.

  7. Neutrino Masses from Neutral Top Partners

    CERN Document Server

    Batell, Brian

    2015-01-01

    We present theories of `Natural Neutrinos' in which neutral fermionic top partner fields are simultaneously the right-handed neutrinos (RHN), linking seemingly disparate aspects of the Standard Model structure: a) The RHN top partners are responsible for the observed small neutrino masses, b) They help ameliorate the tuning in the weak scale and address the little hierarchy problem, and c) The factor of $3$ arising from $N_c$ in the top-loop Higgs mass corrections is countered by a factor $3$ from the number of vector-like generations of RHN. The RHN top partners may arise in pseudo-Nambu-Goldstone-Boson (pNGB) Higgs models such as the Twin Higgs, as well as more general Composite, Little, and Orbifold Higgs scenarios, and three simple example models are presented. This framework firmly predicts a TeV-scale seesaw, as the RHN masses are bounded to be below the TeV scale by naturalness. The generation of light neutrino masses relies on a collective breaking of lepton number, allowing for comparatively large ne...

  8. Top Down proteomics: Facts and perspectives

    International Nuclear Information System (INIS)

    Catherman, Adam D.; Skinner, Owen S.; Kelleher, Neil L.

    2014-01-01

    Highlights: • Top Down versus Bottom Up proteomics analysis. • Separations methods for Top Down proteomics. • Developments in mass spectrometry instrumentation and fragmentation. • Native mass spectrometry. - Abstract: The rise of the “Top Down” method in the field of mass spectrometry-based proteomics has ushered in a new age of promise and challenge for the characterization and identification of proteins. Injecting intact proteins into the mass spectrometer allows for better characterization of post-translational modifications and avoids several of the serious “inference” problems associated with peptide-based proteomics. However, successful implementation of a Top Down approach to endogenous or other biologically relevant samples often requires the use of one or more forms of separation prior to mass spectrometric analysis, which have only begun to mature for whole protein MS. Recent advances in instrumentation have been used in conjunction with new ion fragmentation using photons and electrons that allow for better (and often complete) protein characterization on cases simply not tractable even just a few years ago. Finally, the use of native electrospray mass spectrometry has shown great promise for the identification and characterization of whole protein complexes in the 100 kDa to 1 MDa regime, with prospects for complete compositional analysis for endogenous protein assemblies a viable goal over the coming few years

  9. CSR Position in the Top Management Team

    DEFF Research Database (Denmark)

    Strand, Robert

    Recently, a number of positions with corporate social responsibility (CSR) in the position title have been introduced to the top management teams (TMTs) of some of the world’s largest corporations. I explore this phenomenon. I revisit 10 such positions identified in a previous study to add...

  10. Top Four Trends in Student Information Systems

    Science.gov (United States)

    Weathers, Robert

    2013-01-01

    The modern student information systems (SIS) is a powerful administrative tool with robust functionality. As such, it is essential that school and district administrators consider the top trends in modern student information systems before going forward with system upgrades or new purchases. These trends, described herein, are: (1) Support for…

  11. Top Yukawa deviation in extra dimension

    International Nuclear Information System (INIS)

    Haba, Naoyuki; Oda, Kin-ya; Takahashi, Ryo

    2009-01-01

    We suggest a simple one-Higgs-doublet model living in the bulk of five-dimensional spacetime compactified on S 1 /Z 2 , in which the top Yukawa coupling can be smaller than the naive standard-model expectation, i.e. the top quark mass divided by the Higgs vacuum expectation value. If we find only single Higgs particle at the LHC and also observe the top Yukawa deviation, our scenario becomes a realistic candidate beyond the standard model. The Yukawa deviation comes from the fact that the wave function profile of the free physical Higgs field can become different from that of the vacuum expectation value, due to the presence of the brane-localized Higgs potentials. In the Brane-Localized Fermion scenario, we find sizable top Yukawa deviation, which could be checked at the LHC experiment, with a dominant Higgs production channel being the WW fusion. We also study the Bulk Fermion scenario with brane-localized Higgs potential, which resembles the Universal Extra Dimension model with a stable dark matter candidate. We show that both scenarios are consistent with the current electroweak precision measurements.

  12. Käibe kasvu TOP 100

    Index Scriptorium Estoniae

    2003-01-01

    Käibe kasvu TOP 100. 2002. a. netokäibe kasvust Eesti Ehitus OÜ, Russian Estonian Railway Services OÜ, Baltic Pulp & Paper AS-i ja Water Ser AS-i näitel. Diagrammid. Kommenteerivad Selene Rebane ja Rivo Sarapik

  13. Building bridges across subdisciplines in marine ecology

    Directory of Open Access Journals (Sweden)

    Lawrence R. Pomeroy

    2004-04-01

    Full Text Available Ecology has evolved many subdisciplines whose members do not necessarily communicate regularly through attending the same meetings or reading and publishing in the same journals. As a result, explanations of ecological processes are often limited to a single factor, process, or group of organisms, and this limited approach may fail to provide the best understanding of how communities and ecosystems are assembled and function. Specifically, there is a need to bring together information on the interplay of top-down and bottom-up influences on complete communities consisting of both macroorganisms and microorganisms. A number of examples from the recent literature illustrate the problems encountered in achieving this goal. These include declining fish populations, estuarine eutrophication, the complex origin of a toxic dinoflagellate bloom, and the interactions of microorganisms and macrooorganisms in marine planktonic food webs.

  14. Kinematics of electroweak single top quark production

    International Nuclear Information System (INIS)

    Lueck, Jan; Karlsruhe U., EKP

    2006-01-01

    In this thesis, the t-channel matching procedure of two single-top signal Monte Carlo samples is optimized. The s- and matched t-channel samples, generated by MadEvent, are validated by comparing to ZTOP next-to-leading-order calculations. We find good agreement for all kinematic distributions we investigate, except for softer light quark jets due to gluon radiation. Since this has only minor impact on the s-channel, the corresponding MadEvent sample performs its task as expected. For the t-channel, we can conclude that the applied matching procedure leads to a MadEvent sample that successfully describes the kinematic distributions and rates of the 2nd-b quark. However, small differences remain. The discrepancy in the p T -ordered 2nd-leading light jets is mainly due to the absence of initial state gluon splitting and initial and final state gluon radiation matrix elements in the MadEvent sample production. The subsequent PYTHIA showering of the partons is apparently inappropriate for modeling those contributions and not intended for this purpose. The proper way would be to produce all relevant NLO matrix elements and match them as proposed in reference [15]. At present, an NLO-MC-generator for single-top is in preparation [41]. Probably it will be available for future iterations of single-top analyses and will redundantize further matching procedures. We estimate the systematic uncertainty on the single-top acceptance due to the Monte Carlo modeling and find an uncertainty of about 1% on the t-channel acceptance. We obtain a negligible uncertainty well below 1% on the s-channel acceptance. These acceptance uncertainties are very well acceptable for the single-top analyses that are currently under way. A sensitivity study of the simultaneous cross section measurement of the s- and t-channel single-top production modes is conducted. For this purpose, only statistical uncertainties are included. For a future integrated luminosity of 1 fb -1 , we expect to obtain an s

  15. Top-tagging at the energy frontier

    Science.gov (United States)

    Han, Zhenyu; Son, Minho; Tweedie, Brock

    2018-02-01

    At proposed future hadron colliders and in the coming years at the LHC, top quarks will be produced at genuinely multi-TeV energies. Top-tagging at such high energies forces us to confront several new issues in terms of detector capabilities and jet physics. Here, we explore these issues in the context of some simple JHU/CMS-type declustering algorithms and the N -subjettiness jet-shape variable τ32. We first highlight the complementarity between the two tagging approaches at particle level with respect to discriminating top-jets against gluons and quarks, using multivariate optimization scans. We then introduce a basic fast detector simulation, including electromagnetic calorimeter showering patterns determined from GEANT. We consider a number of tricks for processing the fast detector output back to an approximate particle-level picture. Re-optimizing the tagger parameters, we demonstrate that the inevitable losses in discrimination power at very high energies can typically be ameliorated. For example, percent-scale mistag rates might be maintained even in extreme cases where an entire top decay would sit inside of one hadronic calorimeter cell and tracking information is completely absent. We then study three novel physics effects that will come up in the multi-TeV energy regime: gluon radiation off of boosted top quarks, mistags originating from g →t t ¯ , and mistags originating from q →(W /Z )q collinear electroweak splittings with subsequent hadronic decays. The first effect, while nominally a nuisance, can actually be harnessed to slightly improve discrimination against gluons. The second effect can lead to effective O (1 ) enhancements of gluon mistag rates for tight working points. And the third effect, while conceptually interesting, we show to be of highly subleading importance at all energies.

  16. Top-quark mass and top-quark pole mass measurements with the ATLAS detector

    CERN Document Server

    Barillari, Teresa; The ATLAS collaboration

    2017-01-01

    Results of top-quark mass measurements in the di-lepton and in the all-jets top-antitop decay channels with the ATLAS detector are presented. The measurements are obtained using proton--proton collisions at a centre-of-mass energy \\sqrt{s} = 8 TeV at the CERN Large Hadron Collider. The data set used corresponds to an integrated luminosity of 20.2 fb-1. The top-quark mass in the di-lepton channel is measured to be 172.99 +/-0.41 (stat.) +/- 0.74 (syst.) GeV. In the all-jets analysis the top-quark mass is measured to be 173.72 +/- 0.55 (stat.)+/- 1.01 (syst.) GeV. In addition, the top-quark pole mass is determined from inclusive cross-section measurements in the top-antitop di-lepton decay channel with the ATLAS detector. The measurements are obtained using data at \\sqrt{s} = 7 TeV and \\sqrt{s} =8 TeV corresponding to an integrated luminosity of 4.6 fb-1 and 20.2 fb-1 respectively. The top-quark pole mass is measured to be 172.9^{+2.5}_{-2.6} GeV.

  17. ATLAS + CMS top production and properties: Run 1 legacy

    CERN Document Server

    AUTHOR|(SzGeCERN)641905; The ATLAS collaboration

    2015-01-01

    The large Run 1 data sample of top-quark events collected at the Large Hadron Collider allows a variety of measurements to analyse the production and properties of the top quark. Measurements of top-quark production cross sections and top-quark properties in proton-proton collisions with the ATLAS and CMS detectors at the LHC are presented.

  18. Beyond Standard Model searches with top quarks at ATLAS

    International Nuclear Information System (INIS)

    Chevalier, F.

    2008-01-01

    At the Lhc, the top quark is expected to provide a huge and clean signal. With about eight millions of expected top pairs and three millions of single top events produced per year in the low luminosity runs, and with a low level of backgrounds, the Lhc will open a new opportunity for precision measurements of the top quark properties and for exotic topology searches involving top quarks. As the ATLAS discovery potential on new physics with top quarks is being assessed with many analyses, this paper focuses on two particular topics: heavy neutral resonance and charged Higgs boson searches with top quarks. The analyses and the ATLAS expectations are described.

  19. Measurement of top quark polarisation in t-channel single top quark production

    OpenAIRE

    CMS Collaboration

    2015-01-01

    Journal of High Energy Physics 2016.4 (2016): 073 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA) Artículo escrito por un elevado número de autores, sólo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiera, y los autores pertenecientes a la UAM A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based o...

  20. Studies on top-quark Monte Carlo modelling for Top2016

    CERN Document Server

    The ATLAS collaboration

    2016-01-01

    This note summarises recent studies on Monte Carlo simulation setups of top-quark pair production used by the ATLAS experiment and presents a new method to deal with interference effects for the $Wt$ single-top-quark production which is compared against previous techniques. The main focus for the top-quark pair production is on the improvement of the modelling of the Powheg generator interfaced to the Pythia8 and Herwig7 shower generators. The studies are done using unfolded data at centre-of-mass energies of 7, 8, and 13 TeV.

  1. Top asymmetry and the search for a light hadronic resonance in association with single top

    CERN Document Server

    Jung, Sunghoon; Wells, James D

    2011-01-01

    The exchange of a light $t$-channel flavor-changing gauge boson, $\\Vp$, with mass $\\sim m_{top}$ remains a leading explanation for the anomalous forward backward asymmetry in top quark production at the Tevatron. Unlike other ideas, including heavier $t$-channel mediators, the light $\\Vp$ model is not easily seen in the $\\mtt$ distribution. We advocate a more promising strategy. While current analyses at hadron colliders may not be sensitive, we propose searching for a $jj$ resonance in association with single top that may allow discovery in existing data. Deviations in the lepton charge asymmetry in this sample should also be present.

  2. Emerging biopharmaceuticals from marine actinobacteria.

    Science.gov (United States)

    Hassan, Syed Shams Ul; Anjum, Komal; Abbas, Syed Qamar; Akhter, Najeeb; Shagufta, Bibi Ibtesam; Shah, Sayed Asmat Ali; Tasneem, Umber

    2017-01-01

    Actinobacteria are quotidian microorganisms in the marine world, playing a crucial ecological role in the recycling of refractory biomaterials and producing novel secondary metabolites with pharmaceutical applications. Actinobacteria have been isolated from the huge area of marine organisms including sponges, tunicates, corals, mollusks, crabs, mangroves and seaweeds. Natural products investigation of the marine actinobacteria revealed that they can synthesize numerous natural products including alkaloids, polyketides, peptides, isoprenoids, phenazines, sterols, and others. These natural products have a potential to provide future drugs against crucial diseases like cancer, HIV, microbial and protozoal infections and severe inflammations. Therefore, marine actinobacteria portray as a pivotal resource for marine drugs. It is an upcoming field of research to probe a novel and pharmaceutically important secondary metabolites from marine actinobacteria. In this review, we attempt to summarize the present knowledge on the diversity, chemistry and mechanism of action of marine actinobacteria-derived secondary metabolites from 2007 to 2016. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Top quark pair production at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Baernreuther, Peter

    2012-06-28

    One of the most interesting and manifold processes in the Standard Model of elementary particle physics is the top quark pair production. It enabled the discovery of the top quark at the Tevatron in 1995 and the determination of many of its properties. By means of a precise measurement and calculation of the cross section of top quark pair production it is possible to extract the top quark mass. Improvements in the gluon parton distribution functions (important for the Higgs boson production) or improvements in the prediction of the Higgs mass are also closely linked with the top quark pair production. Furthermore, the production process plays an important role in the discovery of new physics. On the one hand the top quark pair decays form the largest part of the background in many BSM models, on the other hand BSM physics can be detected directly in the decay process by investigating the charge symmetry or the invariant mass spectrum. At the LHC it will be possible for the first time to produce a large amount of top quarks; thereby the statistical errors of the observables will be strongly reduced. The enormous increase in the production rate has two reasons. On the one hand, the acceleration energy of the LHC (14 TeV and 7 TeV) is significantly greater than that of the Tevatron (1.96 Tev). This leads to an increase of the cross section by a factor of 100 ({proportional_to}7.3 pb at the Tevatron to {proportional_to}800 pb at 14 TeV LHC). On the other hand, the luminosity of the LHC outperforms the Tevatron by a factor of 10-100. The reduced experimental errors for the observables demand an improvement of the theoretical error. The experimental accuracy of the LHC and the great relevance of the process led to an intensive activity of different research groups in order to improve the calculation of the cross section of top quark pair production. This work presents for the first time a complete numerical result for the full NNLO correction for the top quark pair

  4. Top quark pair production at the LHC

    International Nuclear Information System (INIS)

    Baernreuther, Peter

    2012-01-01

    One of the most interesting and manifold processes in the Standard Model of elementary particle physics is the top quark pair production. It enabled the discovery of the top quark at the Tevatron in 1995 and the determination of many of its properties. By means of a precise measurement and calculation of the cross section of top quark pair production it is possible to extract the top quark mass. Improvements in the gluon parton distribution functions (important for the Higgs boson production) or improvements in the prediction of the Higgs mass are also closely linked with the top quark pair production. Furthermore, the production process plays an important role in the discovery of new physics. On the one hand the top quark pair decays form the largest part of the background in many BSM models, on the other hand BSM physics can be detected directly in the decay process by investigating the charge symmetry or the invariant mass spectrum. At the LHC it will be possible for the first time to produce a large amount of top quarks; thereby the statistical errors of the observables will be strongly reduced. The enormous increase in the production rate has two reasons. On the one hand, the acceleration energy of the LHC (14 TeV and 7 TeV) is significantly greater than that of the Tevatron (1.96 Tev). This leads to an increase of the cross section by a factor of 100 (∝7.3 pb at the Tevatron to ∝800 pb at 14 TeV LHC). On the other hand, the luminosity of the LHC outperforms the Tevatron by a factor of 10-100. The reduced experimental errors for the observables demand an improvement of the theoretical error. The experimental accuracy of the LHC and the great relevance of the process led to an intensive activity of different research groups in order to improve the calculation of the cross section of top quark pair production. This work presents for the first time a complete numerical result for the full NNLO correction for the top quark pair production in quark anti

  5. Opportunities with top quarks at future circular colliders

    CERN Document Server

    Fuks, Benjamin

    2014-01-01

    We describe various studies relevant for top physics at future circular collider projects currently under discussion. We show how highly-massive top-antitop systems produced in proton-proton collisions at a center-of-mass energy of 100 TeV could be observed and employed for constraining top dipole moments, investigate the reach of future proton-proton and electron-positron machines to top flavor-changing neutral interactions, and discuss top parton densities.

  6. Marine fisheries monitoring programmes in South Africa

    Directory of Open Access Journals (Sweden)

    M. Mayekiso

    2010-01-01

    Full Text Available South Africa was an early leader in multidisciplinary studies of marine resources, particularly with the Benguela Ecology Programme in the 1980s and 1990s and catch records are available for some species dating back more than a century. Resources data have focused on trends in catches, fishing effort and changes in distribution and abundance of harvested resources, which often account for a major part of the structure and functioning of marine ecosystems. Data have been collected by means of fishery-dependent and fishery-independent survey techniques appropriate to each particular stock and analysed using traditional single species stock assessment techniques. The data are complemented by comprehensive information on the environment and top predators and have been analysed using trophodynamic models such as Ecopath with Ecosim. Future approaches include a shift to an ecosystem approach to fisheries monitoring and management, in an attempt to reconcile utilisation and biodiversity conservation objectives. Despite these scientific achievements, the single species approach to the management of most resources still persists, with only limited interactions between competing species or predators and prey being formally taken into account when modelling the stock dynamics and providing management advice to the authorities.

  7. Measurement of the Mass Difference Between Top and Anti-top Quarks at CDF

    CERN Document Server

    Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bisello, D.; Bizjak, I.; Bland, K.R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H.S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Calamba, A.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y.C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chung, W.H.; Chung, Y.S.; Ciocci, M.A.; Clark, A.; Clarke, C.; Compostella, G.; Convery, M.E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C.A.; Cox, D.J.; Crescioli, F.; Cuevas, J.; Culbertson, R.; Dagenhart, D.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Dell'Orso, M.; Demortier, L.; Deninno, M.; Devoto, F.; d'Errico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J.R.; D'Onofrio, M.; Donati, S.; Dong, P.; Dorigo, M.; Dorigo, T.; Ebina, K.; Elagin, A.; Eppig, A.; Erbacher, R.; Errede, S.; Ershaidat, N.; Eusebi, R.; Farrington, S.; Feindt, M.; Fernandez, J.P.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M.J.; Franklin, M.; Freeman, J.C.; Funakoshi, Y.; Furic, I.; Gallinaro, M.; Garcia, J.E.; Garfinkel, A.F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Ginsburg, C.M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; Gonzalez, O.; Gorelov, I.; Goshaw, A.T.; Goulianos, K.; Grinstein, S.; Grosso-Pilcher, C.; Group, R.C.; Guimaraes da Costa, J.; Hahn, S.R.; Halkiadakis, E.; Hamaguchi, A.; Han, J.Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R.F.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Hewamanage, S.; Hocker, A.; Hopkins, W.; Horn, D.; Hou, S.; Hughes, R.E.; Hurwitz, M.; Husemann, U.; Hussain, N.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E.J.; Jindariani, S.; Jones, M.; Joo, K.K.; Jun, S.Y.; Junk, T.R.; Kamon, T.; Karchin, P.E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D.H.; Kim, H.S.; Kim, J.E.; Kim, M.J.; Kim, S.B.; Kim, S.H.; Kim, Y.K.; Kim, Y.J.; Kimura, N.; Kirby, M.; Klimenko, S.; Knoepfel, K.; Kondo, K.; Kong, D.J.; Konigsberg, J.; Kotwal, A.V.; Kreps, M.; Kroll, J.; Krop, D.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kurata, M.; Kwang, S.; Laasanen, A.T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R.L.; Lannon, K.; Lath, A.; Latino, G.; LeCompte, T.; Lee, E.; Lee, H.S.; Lee, J.S.; Lee, S.W.; Leo, S.; Leone, S.; Lewis, J.D.; Limosani, A.; Lin, C.J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D.O.; Liu, C.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maeshima, K.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Martinez, M.; Mastrandrea, P.; Matera, K.; Mattson, M.E.; Mazzacane, A.; Mazzanti, P.; McFarland, K.S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M.N.; Moon, C.S.; Moore, R.; Morello, M.J.; Morlock, J.; Movilla Fernandez, P.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Neubauer, M.S.; Nielsen, J.; Nodulman, L.; Noh, S.Y.; Norniella, O.; Oakes, L.; Oh, S.H.; Oh, Y.D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Paramonov, A.A.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D.E.; Penzo, A.; Phillips, T.J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Prokoshin, F.; Pranko, A.; Ptohos, F.; Punzi, G.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Rescigno, M.; Riddick, T.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W.K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, A.; Schmidt, E.E.; Schwarz, T.; Scodellaro, L.; Scribano, A.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S.Z.; Shears, T.; Shepard, P.F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sinervo, P.; Sliwa, K.; Smith, J.R.; Snider, F.D.; Soha, A.; Sorin, V.; Song, H.; Squillacioti, P.; Stancari, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Strycker, G.L.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P.K.; Thom, J.; Thome, J.; Thompson, G.A.; Thomson, E.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Varganov, A.; Vazquez, F.; Velev, G.; Vellidis, C.; Vidal, M.; Vila, I.; Vilar, R.; Vizan, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wagner, R.L.; Wakisaka, T.; Wallny, R.; Wang, S.M.; Warburton, A.; Waters, D.; Wester, W.C., III; Whiteson, D.; Wicklund, A.B.; Wicklund, E.; Wilbur, S.; Wick, F.; Williams, H.H.; Wilson, J.S.; Wilson, P.; Winer, B.L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U.K.; Yang, Y.C.; Yao, W.M.; Yeh, G.P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G.B.; Yu, I.; Yu, S.S.; Yun, J.C.; Zanetti, A.; Zeng, Y.; Zhou, C.; Zucchelli, S.

    2013-03-18

    We present a measurement of the mass difference between top ($t$) and anti-top ($\\bar{t}$) quarks using $t\\bar{t}$ candidate events reconstructed in the final state with one lepton and multiple jets. We use the full data set of Tevatron $\\sqrt{s} = 1.96$ TeV proton-antiproton collisions recorded by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb$^{-1}$. We estimate event-by-event the mass difference to construct templates for top-quark signal events and background events. The resulting mass difference distribution of data compared to signal and background templates using a likelihood fit yields $\\Delta M_{top} = {M}_{t} - {M}_{\\bar{t}} = -1.95 $pm$ 1.11 (stat) $pm$ 0.59 (syst)$ and is in agreement with the standard model prediction of no mass difference.

  8. PREFACE: 5th International Workshop on Top Quark Physics (TOP2012)

    Science.gov (United States)

    Salamanna, G.; Boisvert, V.; Cerrito, L.; Khan, A.; Moretti, S.; Owen, M.; Schwanenberger, C.

    2013-07-01

    The 5th International Workshop on Top Quark Physics (TOP 2012) took place in Winchester, UK, from the 16-21 September. It gathered students as well as people active in the top quark sector and provided a framework to highlight the newest results and matters related to top quark physics. Discovered in 1995, the top quark is the sixth and heaviest of all quarks, and it is the only one with a lifetime short enough to be observed 'naked'. This makes it an important testing ground in the search for new physics. In fact, the fact of its mass being so much larger than the other quarks, hints at its special role in the Higgs mechanism. For the same reason, in many models of New Physics, new heavy resonances are expected to couple mostly with top quarks. Even if no new particles are observed, the direct correlation between its angular momentum and that of its detectable decay products allows us to probe indirectly New Physics in action when top quarks are created. In this edition of the TOP conference series, for the first time, the agenda was equally balanced between 'traditional' measurements and the now vast number of searches for physics BSM in the top quark sector, thanks mostly to the amount of data collected at the LHC in its Run I. New results were presented by both the Tevatron and the LHC collaborations: improved ttbar and single top cross-section measurements, refined techniques to measure the top quark mass and a large number of results on properties such as spin correlation and W boson polarization in top quark decays were shown. More technical discussions on the experimental issues, both from the detector and the simulation side also took place, drawing together experimentalists and theorists. Reviews of the latest results on ttbar asymmetry both from CDF and D0 and from ATLAS and CMS were shown, and theorists active in the field made some interesting points on this hot topic. Additionally, results on the search for fourth generation fermions and new

  9. Marine Bacterial Genomics

    DEFF Research Database (Denmark)

    Machado, Henrique

    For decades, terrestrial microorganisms have been used as sources of countless enzymes and chemical compounds that have been produced by pharmaceutical and biotech companies and used by mankind. There is a need for new chemical compounds, including antibiotics,new enzymatic activities and new...... microorganisms to be used as cell factories for production. Therefore exploitation of new microbial niches and use of different strategies is an opportunity to boost discoveries. Even though scientists have started to explore several habitats other than the terrestrial ones, the marine environment stands out...... as a hitherto under-explored niche. This thesis work uses high-throughput sequencing technologies on a collection of marine bacteria established during the Galathea 3 expedition, with the purpose of unraveling new biodiversity and new bioactivities. Several tools were used for genomic analysis in order...

  10. Mariner 9 Michelson interferometer.

    Science.gov (United States)

    Hanel, R.; Schlachman, B.; Rodgers, D.; Breihan, E.; Bywaters, R.; Chapman, F.; Rhodes, M.; Vanous, D.

    1972-01-01

    The Michelson interferometer on Mariner 9 measures the thermal emission spectrum of Mars between 200 and 2000 per cm (between 5 and 50 microns) with a spectral resolution of 2.4 per cm in the apodized mode. A noise equivalent radiance of 0.5 x 10 to the minus 7th W/sq cm/ster/cm is deduced from data recorded in orbit around Mars. The Mariner interferometer deviates in design from the Nimbus 3 and 4 interferometers in several areas, notably, by a cesium iodide beam splitter and certain aspects of the digital information processing. Special attention has been given to the problem of external vibration. The instrument performance is demonstrated by calibration data and samples of Mars spectra.

  11. TOP500 Supercomputers for June 2003

    Energy Technology Data Exchange (ETDEWEB)

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2003-06-23

    21st Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 21st edition of the TOP500 list of the world's fastest supercomputers was released today (June 23, 2003). The Earth Simulator supercomputer built by NEC and installed last year at the Earth Simulator Center in Yokohama, Japan, with its Linpack benchmark performance of 35.86 Tflop/s (teraflops or trillions of calculations per second), retains the number one position. The number 2 position is held by the re-measured ASCI Q system at Los Alamos National Laboratory. With 13.88 Tflop/s, it is the second system ever to exceed the 10 Tflop/smark. ASCIQ was built by Hewlett-Packard and is based on the AlphaServerSC computer system.

  12. Top quark kinematics and mass determination

    International Nuclear Information System (INIS)

    Williams, H.H.

    1994-10-01

    An analysis is presented of 10 W + ≥ 3 jet events, each with evidence for the presence of a b quark, that were recently observed by the CDF collaboration. Seven of these events include a fourth jet and can be explicitly reconstructed as t bar t production. The best estimate of the top quark mass is M t = 174 ± 10 -12 +13 GeV/c 2 . A study has also been performed to see if the kinematical properties of events with W + ≥ 3 jets gives evidence for top production. An excess of events with large jet energies, compared to that expected from direct production of W + ≥ 3 jets, is observed. A large fraction of these events also contain a b-quark and a fourth jet

  13. Signs of tops from highly mixed stops

    Energy Technology Data Exchange (ETDEWEB)

    Backović, Mihailo [Center for Cosmology, Particle Physics and Phenomenology - CP3,Universite Catholique de Louvain, Louvain-la-neuve (Belgium); Mariotti, Alberto [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel,and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Spannowsky, Michael [Institute for Particle Physics Phenomenology, Department of Physics,Durham University, Durham DH1 3LE (United Kingdom)

    2015-06-17

    Supersymmetric extensions of the Standard Model with highly mixed squark flavours beyond minimal flavour violation provide interesting scenarios of new physics, which have so far received limited attention. We propose a calculable realization of such scenarios in models of gauge mediation augmented with an extra interaction between the messengers and the up type squark. We compute the supersymmetric spectrum and analyze the flavour physics constraints on such models. In a simplified model approach, we show that scenarios with maximal squark flavour mixing result in interesting phenomenological signatures at the LHC. We show that the model can be probed up to masses of m{sub ũ}≲950 GeV in the single-top event topology at LHC14 with as little as 300 fb{sup −1}. The most distinctive signature of highly mixed scenarios, the same sign positive charge di-top, can be also probed to comparable squark masses at high luminosity LHC14.

  14. The heavy top quark and supersymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Hall, L.J. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

    1997-01-01

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

  15. Three-body Supersymmetric Top Decays

    CERN Document Server

    Belyaev, A; Lola, S; Belyaev, Alexander; Ellis, John; Lola, Smaragda

    2000-01-01

    We discuss three-body supersymmetric top decays, in schemes both with andwithout R-parity conservation, assuming that sfermion masses are larger thanm_t. We find that MSSM top decays into chargino/neutralino pairs have a strongkinematic suppression in the region of the supersymmetric parameter spaceconsistent with the LEP limits, with a decay width =< 10^{-5} GeV. MSSM topdecays into neutralino pairs have less kinematical suppression, but require aflavour-changing vertex, and are likely to have a smaller rate. On the otherhand, R-violating decays to single charginos, neutralinos and conventionalfermions can be larger for values of the R-violating couplings still permittedby other upper limits. The cascade decays of the charginos and neutralinos maylead to spectacular signals with explicit lepton-number violation, such aslike-sign lepton events.

  16. Populating the Landscape: a top down approach

    CERN Document Server

    Hawking, Stephen William; Hertog, Thomas

    2006-01-01

    We put forward a framework for cosmology that combines the string landscape with no boundary initial conditions. In this framework, amplitudes for alternative histories for the universe are calculated with final boundary conditions only. This leads to a top down approach to cosmology, in which the histories of the universe depend on the precise question asked. We study the observational consequences of no boundary initial conditions on the landscape, and outline a scheme to test the theory. This is illustrated in a simple model landscape that admits several alternative inflationary histories for the universe. Only a few of the possible vacua in the landscape will be populated. We also discuss in what respect the top down approach differs from other approaches to cosmology in the string landscape, like eternal inflation.

  17. Probing New Physics with Single Top + X

    International Nuclear Information System (INIS)

    Walker, D.G.E.; Yu, Jiang-Hao; Yuan, C.P.

    2012-01-01

    We investigate single top production in association with a variety of Standard Model final states with a focus on the early LHC run. Here X can be jets, large missing transverse momentum and/or electroweak gauge bosons. For this review, we focus on searches for new W' gauge bosons and heavy B' quarks. A general survey of the possible new physics with associated single top production can be found in literature. In essence, the channel probes a variety of new physics, is intricately tied to the new physics at the TeV scale and is essential for maximizing the potential of the early LHC for new physics. We showed TeV W' bosons and B' heavy quarks are easily accessible during the early LHC running

  18. The heavy top quark and supersymmetry

    International Nuclear Information System (INIS)

    Hall, L.J.; Univ. of California, Berkeley, CA

    1996-01-01

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the standard model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the standard model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed

  19. The heavy top quark and supersymmetry

    International Nuclear Information System (INIS)

    Hall, L.J.

    1997-01-01

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed

  20. Computer networking a top-down approach

    CERN Document Server

    Kurose, James

    2017-01-01

    Unique among computer networking texts, the Seventh Edition of the popular Computer Networking: A Top Down Approach builds on the author’s long tradition of teaching this complex subject through a layered approach in a “top-down manner.” The text works its way from the application layer down toward the physical layer, motivating readers by exposing them to important concepts early in their study of networking. Focusing on the Internet and the fundamentally important issues of networking, this text provides an excellent foundation for readers interested in computer science and electrical engineering, without requiring extensive knowledge of programming or mathematics. The Seventh Edition has been updated to reflect the most important and exciting recent advances in networking.