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Sample records for large potential difference

  1. Comparative studies for different proximity potentials applied to large cluster radioactivity of nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, G. L.; Yao, Y. J.; Guo, M. F.; Pan, M.; Zhang, G. X.; Liu, X. X.

    2016-07-01

    Half-lives of large cluster radioactivity of even-even nuclei calculated by using fourteen proximity potentials are compared to experimental data. The results show that the results of BASS77 and Denisov potentials are most agreeable with the experimental data. Christensen and Winther 1976 potential gives the smallest half-lives. In comparison with the distributions of different proximity potentials and the distributions of total potentials when the values of total potentials are more than the released energy Qc, it is found that at the small distances the large differences of proximity potentials do not affect the calculation results. The different distributions of total potentials affect the penetration probability of large cluster radioactivity, and then affect the half-life of large cluster radioactivity.

  2. Analysis of Large Seeds from Three Different Medicago truncatula Ecotypes Reveals a Potential Role of Hormonal Balance in Final Size Determination of Legume Grains.

    PubMed

    Bandyopadhyay, Kaustav; Uluçay, Orhan; Şakiroğlu, Muhammet; Udvardi, Michael K; Verdier, Jerome

    2016-01-01

    Legume seeds are important as protein and oil source for human diet. Understanding how their final seed size is determined is crucial to improve crop yield. In this study, we analyzed seed development of three accessions of the model legume, Medicago truncatula, displaying contrasted seed size. By comparing two large seed accessions to the reference accession A17, we described mechanisms associated with large seed size determination and potential factors modulating the final seed size. We observed that early events during embryogenesis had a major impact on final seed size and a delayed heart stage embryo development resulted to large seeds. We also observed that the difference in seed growth rate was mainly due to a difference in embryo cell number, implicating a role of cell division rate. Large seed accessions could be explained by an extended period of cell division due to a longer embryogenesis phase. According to our observations and recent reports, we observed that auxin (IAA) and abscisic acid (ABA) ratio could be a key determinant of cell division regulation at the end of embryogenesis. Overall, our study highlights that timing of events occurring during early seed development play decisive role for final seed size determination. PMID:27618017

  3. Large electron screening effect in different environments

    SciTech Connect

    Cvetinović, Aleksandra Lipoglavšek, Matej; Markelj, Sabina; Vesić, Jelena

    2015-10-15

    Electron screening effect was studied in the {sup 1}H({sup 7}Li,α){sup 4}He, {sup 1}H({sup 11}B,α){sup 4}He and {sup 1}H({sup 19}F,αγ){sup 16}O reactions in inverse kinematics on different hydrogen implanted targets. Results show large electron screening potentials strongly dependent on the proton number Z of the projectile.

  4. Homogenization of Periodic Systems with Large Potentials

    NASA Astrophysics Data System (ADS)

    Allaire, Grégoire; Capdeboscq, Yves; Piatnitski, Andrey; Siess, Vincent; Vanninathan, M.

    2004-11-01

    We consider the homogenization of a system of second-order equations with a large potential in a periodic medium. Denoting by ɛ the period, the potential is scaled as ɛ-2. Under a generic assumption on the spectral properties of the associated cell problem, we prove that the solution can be approximately factorized as the product of a fast oscillating cell eigenfunction and of a slowly varying solution of a scalar second-order equation. This result applies to various types of equations such as parabolic, hyperbolic or eigenvalue problems, as well as fourth-order plate equation. We also prove that, for well-prepared initial data concentrating at the bottom of a Bloch band, the resulting homogenized tensor depends on the chosen Bloch band. Our method is based on a combination of classical homogenization techniques (two-scale convergence and suitable oscillating test functions) and of Bloch waves decomposition.

  5. Large data analysis of different sensory modalities

    NASA Astrophysics Data System (ADS)

    Hsu, Ming-Kai; Szu, Harold

    2014-05-01

    We exam the historical remote digital video and in situ analog acoustic data analyses from the modern Large Data Analysis standpoint. We discussed a potential automation from traditional search engine to modern one. We exam the mathematic theory to answer where the nonlinear dimensional analysis assume a local flat space where linear eigenvalue provided the independent components, then the component is extrapolated to original nonlinear space and assume the local flat reduction remains meaningful at global nonlinear domain.

  6. Global differences between moderate and large storms

    NASA Astrophysics Data System (ADS)

    Valek, P. W.; Buzulukova, N.; Fok, M. C. H.; Goldstein, J.; Keesee, A. M.; McComas, D. J.; Perez, J. D.

    2015-12-01

    The current solar maximum has been relatively quiet compared to previous solar cycles. Whereas numerous moderate storms (Dst < -50 nT) have occurred, there have been only a small number of large (Dst < - 100 nT) and extreme (Dst < -200 nT) storms. Throughout this sequence of storms, the Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission has since 2008 observed the inner magnetosphere. TWINS consists of two ENA cameras flown aboard two separate spacecraft in Molniya orbits. TWINS images the ENA emissions from the inner magnetosphere across a broad range of energies (1 to 100 keV for H, 16 to 256 keV for O). This allows TWINS to observe the evolution in space and time of the trapped and precipitating particles most relevant for storm time dynamics on very high time scales (i.e., minutes). Here we will present the differences seen between moderate storms and the two large storms of 17 March 2015 (Dst < -223, St. Patrick's day storm) and 22 June 2015 (Dst < -195 nT). We will present composition-separated ENA observations of the inner magnetosphere covering the both the medium (1 to 30 keV) and high (30 to > 100 keV) energy ranges, and describe how the inner magnetosphere evolves during storm time.

  7. Accuracy potentials for large space antenna structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1980-01-01

    The relationships among materials selection, truss design, and manufacturing techniques in the interest of surface accuracies for large space antennas are discussed. Among the antenna configurations considered are: tetrahedral truss, pretensioned truss, and geodesic dome and radial rib structures. Comparisons are made of the accuracy achievable by truss and dome structure types for a wide variety of diameters, focal lengths, and wavelength of radiated signal, taking into account such deforming influences as solar heating-caused thermal transients and thermal gradients.

  8. Large Earthquake Potential in the Southeast Caribbean

    NASA Astrophysics Data System (ADS)

    Mencin, D.; Mora-Paez, H.; Bilham, R. G.; Lafemina, P.; Mattioli, G. S.; Molnar, P. H.; Audemard, F. A.; Perez, O. J.

    2015-12-01

    The axis of rotation describing relative motion of the Caribbean plate with respect to South America lies in Canada near Hudson's Bay, such that the Caribbean plate moves nearly due east relative to South America [DeMets et al. 2010]. The plate motion is absorbed largely by pure strike slip motion along the El Pilar Fault in northeastern Venezuela, but in northwestern Venezuela and northeastern Colombia, the relative motion is distributed over a wide zone that extends from offshore to the northeasterly trending Mérida Andes, with the resolved component of convergence between the Caribbean and South American plates estimated at ~10 mm/yr. Recent densification of GPS networks through COLOVEN and COCONet including access to private GPS data maintained by Colombia and Venezuela allowed the development of a new GPS velocity field. The velocity field, processed with JPL's GOA 6.2, JPL non-fiducial final orbit and clock products and VMF tropospheric products, includes over 120 continuous and campaign stations. This new velocity field along with enhanced seismic reflection profiles, and earthquake location analysis strongly suggest the existence of an active oblique subduction zone. We have also been able to use broadband data from Venezuela to search slow-slip events as an indicator of an active subduction zone. There are caveats to this hypothesis, however, including the absence of volcanism that is typically concurrent with active subduction zones and a weak historical record of great earthquakes. A single tsunami deposit dated at 1500 years before present has been identified on the southeast Yucatan peninsula. Our simulations indicate its probable origin is within our study area. We present a new GPS-derived velocity field, which has been used to improve a regional block model [based on Mora and LaFemina, 2009-2012] and discuss the earthquake and tsunami hazards implied by this model. Based on the new geodetic constraints and our updated block model, if part of the

  9. How Large Are Cognitive Gender Differences?

    ERIC Educational Resources Information Center

    Hyde, Janet Shibley

    1981-01-01

    This study applied meta-analysis techniques to the gender studies cited by Maccoby and Jacklin and assessed the magnitude of cognitive gender differences. Results indicated that gender differences in verbal, quantitative, and visual-spatial ability were very small. (Author/APM)

  10. Electrical potential difference during laser welding

    NASA Astrophysics Data System (ADS)

    Zohm, H.; Ambrosy, G.; Lackner, K.

    2015-01-01

    We present a new model for the generation of thermoelectric currents during laser welding, taking into account sheath effects at both contact points as well as the potential drop within the quasi-neutral plasma generated by the laser. We show that the model is in good agreement with experimentally measured electric potential difference between the hot and the cold parts of the welded workpiece. In particular, all three elements of the model are needed to correctly reproduce the sign of the measured voltage difference. The mechanism proposed relies on the temperature dependence of the electron flux from the plasma to the workpiece and hence does not need thermoemission from the workpiece surface to explain the experimentally observed sign and magnitude of the potential drop.

  11. Integrating Different Types of Nanowire Sensors in a Large Array

    NASA Astrophysics Data System (ADS)

    Dan, Yaping; Evoy, Stephane; Johnson, A. T. Charlie

    2008-03-01

    Biological olfactory systems have a key structural feature: different types of sensors in a large array. Humans, for example, possess several hundred distinct types of sensing cells, a level of sensor diversity not yet achieved in artificial olfactory systems. Here, we demonstrate a simple and low-cost electrochemical approach to integrate large numbers of different types of nanowire sensors in an array on the same silicon wafer. In our approach, nanowires are grown inside an on-chip nanochannel template by electrochemistry with each horizontal channel connected to a gold electrode. This design allows for addressable synthesis of a specific type of nanowire in specified channels by providing a voltage to the electrodes connecting to those channels. The process can be further repeated to produce different types of nanowires in other channels using different electroplating solutions. The scale and diversity of this array have a potential to compete with those of biological olfactory systems and the synthesis process is cost-effective enough for commercialization.

  12. Resolvent estimates for perturbations by large magnetic potentials

    SciTech Connect

    Cardoso, Fernando Cuevas, Claudio; Vodev, Georgi

    2014-02-15

    We prove optimal high-frequency resolvent estimates for self-adjoint operators of the form G = −Δ + ib(x) · ∇ + i∇ · b(x) + V(x) on L{sup 2}(R{sup n}), n ⩾ 3, where b(x) and V(x) are large magnetic and electric potentials, respectively. No continuity of the magnetic potential is assumed.

  13. Accuracy potential of large-format still-video cameras

    NASA Astrophysics Data System (ADS)

    Maas, Hans-Gerd; Niederoest, Markus

    1997-07-01

    High resolution digital stillvideo cameras have found wide interest in digital close range photogrammetry in the last five years. They can be considered fully autonomous digital image acquisition systems without the requirement of permanent connection to an external power supply and a host computer for camera control and data storage, thus allowing for convenient data acquisition in many applications of digital photogrammetry. The accuracy potential of stillvideo cameras has been extensively discussed. While large format CCD sensors themselves can be considered very accurate measurement devices, lenses, camera bodies and sensor mounts of stillvideo cameras are not compression techniques in image storage, which may also affect the accuracy potential. This presentation shows recent experiences from accuracy tests with a number of large format stillvideo cameras, including a modified Kodak DCS200, a Kodak DCS460, a Nikon E2 and a Polaroid PDC-2000. The tests of the cameras include absolute and relative measurements and were performed using strong photogrammetric networks and good external reference. The results of the tests indicate that very high accuracies can be achieved with large blocks of stillvideo imagery especially in deformation measurements. In absolute measurements, however, the accuracy potential of the large format CCD sensors is partly ruined by a lack of stability of the cameras.

  14. Large wind turbine generators. [NASA program status and potential costs

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Donovon, R. M.

    1978-01-01

    The large wind turbine portion of the Federal Wind Energy Program consists of two major project efforts: (1) the Mod-0 test bed project for supporting research technology, and (2) the large experimental wind turbines for electric utility applications. The Mod-0 has met its primary objective of providing the entire wind energy program with early operations and performance data. The large experimental wind turbines to be tested in utility applications include three of the Mod-0A (200 kW) type, one Mod-1 (2000 kW), and possibly several of the Mod-2 (2500 kW) designs. This paper presents a description of these wind turbine systems, their programmatic status, and a summary of their potential costs.

  15. Exploiting the Potential Differences in Pasture Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperate grasses grown for pasture in Wisconsin exhibit a range of chemical and physical characteristics that influence their utilization by grazing cattle. Potential intake of all grasses declines with maturity due to decreasing cell wall digestiblity, but the leaves and stems of orchardgrass and...

  16. Energy potential and early operational experience for large wind turbines

    NASA Technical Reports Server (NTRS)

    Robbins, W. H.; Thomas, R. L.

    1980-01-01

    Projections for the total potential output of large wind turbines in the U.S. are reviewed. NASA has developed nine large windpowered generators, of 100 kW, 200 kW, 2 MW, and 2.5 MW capacities, with rotors 100-300 ft in diameter, and all with horizontal axes. Approximately 214,000 sq miles of the U.S. have been determined as having substantial wind regimes and terrain suitable for large wind turbine siting. This translates into 340,000 Mod 2 (2.5 MW) wind turbines producing 4.9 quads of electricity annually, equivalent to saving 2.5 billion barrels of oil/yr. The cost of electricity is seen as the critical factor in utility acceptance of large wind turbines, and the Mod 2 machines are noted to achieve the 2-4 cents/kWh (1977 dollars) COE which is necessary. Problems such as pollution, including visual, auditory, EM, and land use difficulties are considered, and solutions are indicated.

  17. Zooplankton as Potential Indicators of Biotic Condition in Large Rivers

    NASA Astrophysics Data System (ADS)

    Medley, K. A.; Havel, J. E.; Jack, J. D.

    2005-05-01

    As part of the Environmental Monitoring and Assessment Program (EMAP), supported by the U.S. Environmental Protection Agency, we are examining zooplankton diversity and abundance in three large rivers (Missouri, Ohio, and upper Mississippi). These rivers are particularly interesting because of large differences in their hydrologic patterns, resulting primarily from their different management strategies. Preliminary data from summer 2004 surveys of the Missouri and Ohio rivers reveals high taxonomic diversity of rotifers (32 genera), cladocerans (22 species), and copepods. Rotifers are numerically dominant in all river samples except in the late summer Ohio River samples, where they are occasionally co-dominant with calanoid copepods. Using multivariate analyses, we will present a comparison of zooplankton diversity between rivers, among sites within rivers, and correspondence with 35 physico-chemical properties of the river. These data will be used to develop bioindicators of the current condition of each river in order to support conservation and restoration decisions by management agencies.

  18. Potential Large Decadal Missions Enabled by Nasas Space Launch System

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Hopkins, Randall C.; Schnell, Andrew; Smith, David Alan; Jackman, Angela; Warfield, Keith R.

    2016-01-01

    Large space telescope missions have always been limited by their launch vehicle's mass and volume capacities. The Hubble Space Telescope (HST) was specifically designed to fit inside the Space Shuttle and the James Webb Space Telescope (JWST) is specifically designed to fit inside an Ariane 5. Astrophysicists desire even larger space telescopes. NASA's "Enduring Quests Daring Visions" report calls for an 8- to 16-m Large UV-Optical-IR (LUVOIR) Surveyor mission to enable ultra-high-contrast spectroscopy and coronagraphy. AURA's "From Cosmic Birth to Living Earth" report calls for a 12-m class High-Definition Space Telescope to pursue transformational scientific discoveries. NASA's "Planning for the 2020 Decadal Survey" calls for a Habitable Exoplanet Imaging (HabEx) and a LUVOIR as well as Far-IR and an X-Ray Surveyor missions. Packaging larger space telescopes into existing launch vehicles is a significant engineering complexity challenge that drives cost and risk. NASA's planned Space Launch System (SLS), with its 8 or 10-m diameter fairings and ability to deliver 35 to 45-mt of payload to Sun-Earth-Lagrange-2, mitigates this challenge by fundamentally changing the design paradigm for large space telescopes. This paper reviews the mass and volume capacities of the planned SLS, discusses potential implications of these capacities for designing large space telescope missions, and gives three specific mission concept implementation examples: a 4-m monolithic off-axis telescope, an 8-m monolithic on-axis telescope and a 12-m segmented on-axis telescope.

  19. Individual Skill Differences and Large-Scale Environmental Learning

    ERIC Educational Resources Information Center

    Fields, Alexa W.; Shelton, Amy L.

    2006-01-01

    Spatial skills are known to vary widely among normal individuals. This project was designed to address whether these individual differences are differentially related to large-scale environmental learning from route (ground-level) and survey (aerial) perspectives. Participants learned two virtual environments (route and survey) with limited…

  20. Central ridge of Newfoundland: Little explored, potential large

    SciTech Connect

    Silva, N.R. De )

    1993-10-25

    The Central ridge on the northeastern Grand Banks off Newfoundland represents a large area with known hydrocarbon accumulations and the potential for giant fields. It covers some 17,000 sq km with water less than 400 m deep. The first major hydrocarbon discovery on the Newfoundland Grand Banks is giant Hibernia field in the Jeanne d'Arc basin. Hibernia field, discovered in 1979, has reserves of 666 million bbl and is due onstream in 1997. Since Hibernia, 14 other discoveries have been made on the Grand Banks, with three on the Central ridge. Oil was first discovered on Central Ridge in 1980 with the Mobil et al. South Tempest G-88 well. In 1982 gas was discovered with the Mobil et al. North Dana I-43 well 30 km northeast of the earlier discovery. In 1983 gas and condensate were discovered with the Husky-Bow Valley et al. Trave E-87 well 20 km south of the South Tempest well. These discoveries are held under significant discovery licenses and an additional 2,400 sq km are held under exploration licenses. The paper discusses the history of the basin, the reservoir source traps, and the basin potential.

  1. Individual skill differences and large-scale environmental learning.

    PubMed

    Fields, Alexa W; Shelton, Amy L

    2006-05-01

    Spatial skills are known to vary widely among normal individuals. This project was designed to address whether these individual differences are differentially related to large-scale environmental learning from route (ground-level) and survey (aerial) perspectives. Participants learned two virtual environments (route and survey) with limited exposure and tested on judgments about relative locations of objects. They also performed a series of spatial and nonspatial component skill tests. With limited learning, performance after route encoding was worse than performance after survey encoding. Furthermore, performance after route and survey encoding appeared to be preferentially linked to perspective and object-based transformations, respectively. Together, the results provide clues to how different skills might be engaged by different individuals for the same goal of learning a large-scale environment. PMID:16719662

  2. Mixing device for materials with large density differences

    DOEpatents

    Gregg, D.W.

    1994-08-16

    An auger-tube pump mixing device is disclosed for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided. 2 figs.

  3. Mixing device for materials with large density differences

    DOEpatents

    Gregg, David W.

    1994-01-01

    An auger-tube pump mixing device for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided.

  4. Oral potentially malignant disorders in a large dental population

    PubMed Central

    Alessandro, VILLA; Anita, GOHEL

    2014-01-01

    Objectives Oral cancer (OC) may be preceded by clinically evident oral potentially malignant disorders (OPMDs). Oral carcinogenesis is a multistep process that begins as epithelial hyperplasia and progresses to oral epithelial dysplasia and finally to fully malignant phenotypes. The aim of our study was to estimate the prevalence of OPMDs in a large population of dental patients. Methods Patients were seen in the Oral Diagnosis and Oral Medicine clinics at Boston University Henry M. Goldman School of Dental Medicine between July 2013 and February 2014 and received a comprehensive oral examination to identify any possible mucosal lesions. Patients with a suspected OPMD (submucous fibrosis, oral lichen planus, leukoplakia and erythroplakia) that did not resolve in 2–3 weeks received a biopsy for definitive diagnosis. Logistic regression models were used to explore the relationship between OPMDs and associated risk factors. Results A total of 3,142 patients received a comprehensive oral examination [median age: 43 (range: 18–97); 54.3% females]. Among these, 4.5% had an oral mucosal lesion with 0.9% being an OPMD (one submucous fibrosis, three epithelial dysplasias, fourteen with hyperkeratosis/epithelial hyperplasia and nine with oral lichen planus). Males and current smokers were associated with higher odds of having OPMD (OR 1.7, 95% CI 0.8–3.8; OR 1.9, 95%CI 0.8–4.1). Increasing age was associated with having OPMDs (p<0.01). Conclusion Optimal oral visual screening for OC remains a simple and essential tool to identify any suspicious lesions and potentially increase survival. Although OPMDs were rare, our results confirm the importance of a thorough chairside screening by dentists and dental students to detect any mucosal changes. PMID:25591015

  5. Multipole moments for embedding potentials: Exploring different atomic allocation algorithms.

    PubMed

    S Nørby, Morten; Magnus Haugaard Olsen, Jógvan; Kongsted, Jacob; Aagard Jensen, Hans Jørgen

    2016-07-01

    Polarizable quantum mechanical (QM)/molecular mechanics (MM)-embedding methods are currently among the most promising methods for computationally feasible, yet reliable, production calculations of localized excitations and molecular response properties of large molecular complexes, such as proteins and RNA/DNA, and of molecules in solution. Our aim is to develop a computational methodology for distributed multipole moments and their associated multipole polarizabilities which is accurate, computationally efficient, and with smooth convergence with respect to multipole order. As the first step toward this goal, we herein investigate different ways of obtaining distributed atom-centered multipole moments that are used in the construction of the electrostatic part of the embedding potential. Our objective is methods that not only are accurate and computationally efficient, but which can be consistently extended with site polarizabilities including internal charge transfer terms. We present a new way of dealing with well-known problems in relation to the use of basis sets with diffuse functions in conventional atomic allocation algorithms, avoiding numerical integration schemes. Using this approach, we show that the classical embedding potential can be systematically improved, also when using basis sets with diffuse functions, and that very accurate embedding potentials suitable for QM/MM embedding calculations can be acquired. © 2016 Wiley Periodicals, Inc. PMID:27187063

  6. Peru onshore-deepwater basins should have large potential

    SciTech Connect

    Zuniga-Rivero, F.; Keeling, J.A.; Hay-Roe, H.

    1998-10-19

    Perupetro`s recent announcement that 13 offshore exploration blocks of nearly 1 million acres each will be offered for bids in the fourth quarter of 1998 has reawakened interest in this extensive, largely unexplored area. The new government policy, combined with the results of modern, deep-probing seismic surveys, has already led to a stepped-up search for oil and gas that will probably escalate. Most of Peru`s ten coastal basins are entirely offshore, but at both ends of the 1,500-mile coastline the sedimentary basins stretch from onshore across the continental shelf and down the continental slope. Two of these basin areas, both in the north, have commercial production. The third, straddling the country`s southern border, has never been drilled either on land or offshore. The Peruvian sectors of these three basins total roughly 50,000 sq miles in area, 75% offshore. All have major oil and gas potential. They are described individually in this article, an update in the ongoing studies last reported at the 1998 Offshore Technology Conference and in the first article of this series.

  7. Ionization potentials of large sodium doped ammonia clusters.

    PubMed

    Steinbach, C; Buck, U

    2005-04-01

    In a continuous neat supersonic expansion ammonia clusters are generated and doped with sodium atoms in a pickup cell. Thus clusters of the form Na(NH(3))(n) are produced that are photoionized by a tunable dye laser system. The ions are mass analyzed in a reflectron time-of-flight mass spectrometer, and the wavelength dependent ion signals serve for the determination of the ionization potentials (IP) of the different clusters in the size range 10< or =n< or =1500. Aside from a plateau for 10< or =n< or =17 and smaller steps at n=24, 35, and 59 on the average a continuous decrease of the IP with cluster size is observed. The IPs in this size range are linear with (n+1)(-13) and extrapolate to IP(n=infinity)=1.66+/-0.01 eV. The slope is consistent with a dielectric continuum model of the solvated electron and the dielectric constant of the solid. The extrapolated IPs are compared with results obtained for negative ammonia cluster ions and metallic solutions in liquid ammonia. Differences are explained by the presence of counterions and their various distances from the solvated electron. PMID:15847459

  8. Ionization potentials of large sodium doped ammonia clusters

    NASA Astrophysics Data System (ADS)

    Steinbach, C.; Buck, U.

    2005-04-01

    In a continuous neat supersonic expansion ammonia clusters are generated and doped with sodium atoms in a pickup cell. Thus clusters of the form Na(NH3)n are produced that are photoionized by a tunable dye laser system. The ions are mass analyzed in a reflectron time-of-flight mass spectrometer, and the wavelength dependent ion signals serve for the determination of the ionization potentials (IP) of the different clusters in the size range 10⩽n ⩽1500. Aside from a plateau for 10⩽n⩽17 and smaller steps at n =24, 35, and 59 on the average a continuous decrease of the IP with cluster size is observed. The IPs in this size range are linear with (n+1)-1/3 and extrapolate to IP (n=∞)=1.66±0.01eV. The slope is consistent with a dielectric continuum model of the solvated electron and the dielectric constant of the solid. The extrapolated IPs are compared with results obtained for negative ammonia cluster ions and metallic solutions in liquid ammonia. Differences are explained by the presence of counterions and their various distances from the solvated electron.

  9. Assessing carbon dynamics in semiarid ecosystems : Balancing potential gains with potential large rapid losses

    SciTech Connect

    Breshears, D. D.; Ebinger, M. H.; Unkefer, P. J.

    2001-01-01

    Photosynthesis and respiration are the largest fluxes into and out of the biosphere (Molles 1999). Consequently, small changes in these fluxes can potentially produce large changes in the storage of carbon in the biosphere. Terrestrial carbon fluxes account for more than half of the carbon transferred between the atmosphere and the earth's surface (about 120 GigaTons/year), and current stores of carbon in terrestrial ecosystem are estimated at 2060 GigaTons. Increasing attention is being focused on the role of managing and sequestering carbon in the terrestrial biosphere as a means for addressing global climate change (IGBP, 1998; U.S. Department of Energy, 1999). Terrestrial ecosystems are widely recognized as a major biological scrubber for atmosphereic CO{sub 2} and their ability to finction as such can be increased significantly over the next 25 years through careful manipulation. The potential for terrestrial carbon gains has been the subject of much attention (Dixon et al., 1994; Masera et al. 1997; Cao and Woodward, 1998; DeLucia et al. 1999). In contrast to other strategies for reducing net carbon emissions, terrestrial sequestration has the potential for rapid implementation. Strategies that focus on soil carbon are likely to be effective because in addition to being a storage pool of carbon, soil carbon also improves site productivity through improving soil quality (e.g., water retention and nutrient availability). The carbon pool in soils is immense and highly dynamic. The flux of carbon into and out of soils is one of the largest uncertainties in the total mass balance of global carbon (NRC, 1999; La1 et al., 1998; Cambardella, 1998). Reducing these uncertainties is key to developing carbon sequestration strategies. Soil carbon pools have been greatly depleted over recent centuries, and there is potential to increase storage of carbon in these soils through effective land management. Whereas carbon in vegetation can be managed directly through land use

  10. Bernoulli effect and contact potential difference in superconductors

    SciTech Connect

    Omel'yanchuk, A.N.; Beloborod'ko, S.I.

    1983-10-01

    An expression is derived for the Bernoulli potential that arises in superconductors with an inhomogeneous current distribution. The expression is valid for arbitrary temperatures and superfluid velocities. In the superconductor--dielectric--superconductor system we consider the Bernoulli effect, which manifests itself in a contact potential difference between the superconductors. The potential difference is determined by the currents flowing through one plate of the contact and can be measured with a voltmeter in the quasi-stationary regime.

  11. Thermoelectric properties and efficiency measurements under large temperature differences.

    PubMed

    Muto, A; Kraemer, D; Hao, Q; Ren, Z F; Chen, G

    2009-09-01

    The maximum efficiency of a thermoelectric generator is determined by the material's dimensionless figure of merit ZT. Real thermoelectric material properties are highly temperature dependent and are often measured individually using multiple measurement tools on different samples. As a result, reported ZT values have large uncertainties. In this work we present an experimental technique that eliminates some of these uncertainties. We measure the Seebeck coefficient, electrical conductivity, and thermal conductivity of a single element or leg, as well as the conversion efficiency, under a large temperature difference of 2-160 degrees C. The advantages of this technique include (1) the thermoelectric leg is mounted only once and all measurements are in the same direction and (2) the measured properties are corroborated by efficiency measurements. The directly measured power and efficiency are compared to the values calculated from the measured properties and agree within 0.4% and 2%, respectively. The realistic testing conditions of this technique make it ideal for material characterization prior to implementation in a real thermoelectric generator. PMID:19791947

  12. Horizontal differences in ecosystem metabolism of a large shallow lake

    NASA Astrophysics Data System (ADS)

    Idrizaj, Agron; Laas, Alo; Anijalg, Urmas; Nõges, Peeter

    2016-04-01

    The causes of horizontal differences in metabolic activities between lake zones are still poorly understood. We carried out a two-year study of lake metabolism in two contrasting parts of a large shallow lake using the open-water technique based on high-frequency measurements of dissolved oxygen concentrations. We expected that the more sheltered and macrophyte-rich southern part of the lake receiving a high hydraulic load from the main inflow will exhibit equal or higher rate of metabolic processes compared to the open pelagic zone, and higher temporal variability, including anomalous metabolic estimates such as negative gross primary production (GPP) or community respiration (CR) due to rapid water exchange. Our results showed that anomalous metabolic estimates occurred at both stations with a similar frequency and were related rather to certain wind directions, which likely contributed to stronger water exchange between the littoral and pelagic zones. Periods of auto- and heterotrophy (daily mean NEP> or <0) had a 50:50 distribution at the Central Station while the proportions were 30:70 at the Southern Station. High areal GPP estimated in our study exceeding nearly twice the long-term average 14C primary production, showed the advantages of the free-water technique in integrating the metabolism of all communities, a large part of which has remained undetected by the traditional bottle or chamber incubation techniques.

  13. Finite difference methods for the solution of unsteady potential flows

    NASA Technical Reports Server (NTRS)

    Caradonna, F. X.

    1982-01-01

    Various problems which are confronted in the development of an unsteady finite difference potential code are reviewed mainly in the context of what is done for a typical small disturbance and full potential method. The issues discussed include choice of equations, linearization and conservation, differencing schemes, and algorithm development. A number of applications, including unsteady three dimensional rotor calculations, are demonstrated.

  14. Effect of Several Drugs on Gastric Potential Difference in Man

    PubMed Central

    Murray, H. S.; Strottman, M. P.; Cooke, A. R.

    1974-01-01

    Measurement of gastric mucosal potential difference was used to study the effect on the gastric mucosal barrier in six volunteer subjects of several drugs known to provoke ulcers. Potential differences were also recorded in nine patients with rheumatoid arthritis being treated with long-term aspirin and five patients on long-term prednisone. Unbuffered aspirin and ethanol “broke” the barrier as shown by a rapid fall in potential difference. The effects of aspirin were dose related, with 600 mg causing a greater reduction than 300 mg. The effects of aspirin and ethanol given together were additive and caused the greatest fall in potential difference. Sodium acetylsalicylate did not alter the normal potential difference. Indomethacin, phenylbutazone, and prednisone all failed to cause any change in potential difference. The patients on long-term aspirin and prednisone had readings within the normal range and responded the same as normal subjects to an acute challenge. These studies show that aspirin and ethanol will damage the gastric mucosal barrier but that indomethacin, phenylbutazone, and prednisone do not. PMID:4808815

  15. Potential role of large oceanic diatoms in new primary production

    NASA Astrophysics Data System (ADS)

    Goldman, Joel C.

    1993-01-01

    Very large phytoplankton species >50 μm in size, particularly diatoms, generally are found in background numbers throughout the euphotic zone of oceanic waters. Yet, when responding to episodic injections of new nutrients across the nutricline at the base of the euphotic zone these phototrophs may make a disproportionately large contribution to new primary production. To test this concept, we isolated a group of large diatoms from the Sargasso Sea and found that the specific growth rate of several of these species in culture was great enough at the ≈2% light level in oligotrophic waters to meet the requirements of several hypothetical scenarios in which annual rates of new production from the sum of one or more episodic blooms were equal to contemporary estimates. Two of the fast-growing species, Stephanopyxis palmeriana (Greville) Grunow and Pseudoguinardia recta von Stosch, formed giant flocculant masses while growing. Such masses could sink rapidly out of the euphotic zone or be a direct food source for invertebrates or fish higher up the food chain. Not only would a short, simple trophic system with low losses result, but the events would virtually be impossible to observe with conventional sampling.

  16. Approximate registration of point clouds with large scale differences

    NASA Astrophysics Data System (ADS)

    Novak, D.; Schindler, K.

    2013-10-01

    3D reconstruction of objects is a basic task in many fields, including surveying, engineering, entertainment and cultural heritage. The task is nowadays often accomplished with a laser scanner, which produces dense point clouds, but lacks accurate colour information, and lacks per-point accuracy measures. An obvious solution is to combine laser scanning with photogrammetric recording. In that context, the problem arises to register the two datasets, which feature large scale, translation and rotation differences. The absence of approximate registration parameters (3D translation, 3D rotation and scale) precludes the use of fine-registration methods such as ICP. Here, we present a method to register realistic photogrammetric and laser point clouds in a fully automated fashion. The proposed method decomposes the registration into a sequence of simpler steps: first, two rotation angles are determined by finding dominant surface normal directions, then the remaining parameters are found with RANSAC followed by ICP and scale refinement. These two steps are carried out at low resolution, before computing a precise final registration at higher resolution.

  17. Pushbroom radiometry and its potential using large space antennas

    NASA Technical Reports Server (NTRS)

    Harrington, R. F.; Keafer, L. S., Jr.

    1983-01-01

    Electromagnetic radiation is emitted by matter which was heated to a temperature above absolute zero. The amount of blackbody radiation in the microwave frequency region of interest (10 to the 8th power f 10 to the 10th power Hz) emitted by matter can be determined from the Rayleigh-Jeans approximation to Planck's Radiation Law. The amount of electromagnetic radiation from matter which is not a blackbody is a function of the emissivity of the material. The emissivity is a factor less than unity and is a function of several parameters including chemical composition, temperature, frequency, surface characteristics, and viewing angle. A radiometer is an instrument which detects and provides a measure of the electromagnetic radiation being emitted by a material or surface area within the radiometer's antenna beamwidth. Microwave radiometers provide the capability for remote measurements from Earth orbits of geophysical parameters. These measurements will require the use of a microwave imaging radiometer using a large aperture deployable antenna with multiple beams in a pushbroom mode to achieve high spatial resolution and large swath width.

  18. Potential for large outbreaks of Ebola virus disease.

    PubMed

    Camacho, A; Kucharski, A J; Funk, S; Breman, J; Piot, P; Edmunds, W J

    2014-12-01

    Outbreaks of Ebola virus can cause substantial morbidity and mortality in affected regions. The largest outbreak of Ebola to date is currently underway in West Africa, with 3944 cases reported as of 5th September 2014. To develop a better understanding of Ebola transmission dynamics, we revisited data from the first known Ebola outbreak, which occurred in 1976 in Zaire (now Democratic Republic of Congo). By fitting a mathematical model to time series stratified by disease onset, outcome and source of infection, we were able to estimate several epidemiological quantities that have previously proved challenging to measure, including the contribution of hospital and community infection to transmission. We found evidence that transmission decreased considerably before the closure of the hospital, suggesting that the decline of the outbreak was most likely the result of changes in host behaviour. Our analysis suggests that the person-to-person reproduction number was 1.34 (95% CI: 0.92-2.11) in the early part of the outbreak. Using stochastic simulations we demonstrate that the same epidemiological conditions that were present in 1976 could have generated a large outbreak purely by chance. At the same time, the relatively high person-to-person basic reproduction number suggests that Ebola would have been difficult to control through hospital-based infection control measures alone. PMID:25480136

  19. Finite difference methods for the solution of unsteady potential flows

    NASA Technical Reports Server (NTRS)

    Caradonna, F. X.

    1985-01-01

    A brief review is presented of various problems which are confronted in the development of an unsteady finite difference potential code. This review is conducted mainly in the context of what is done for a typical small disturbance and full potential methods. The issues discussed include choice of equation, linearization and conservation, differencing schemes, and algorithm development. A number of applications including unsteady three-dimensional rotor calculation, are demonstrated.

  20. Evaluation of potential runaway generation in large-tokamak disruptions

    SciTech Connect

    Fleischmann, H.H.; Zweben, S.J. . Plasma Physics Lab. Cornell Univ., Ithaca, NY . School of Applied and Engineering Physics)

    1993-06-01

    A detailed evaluation of various potential mechanisms for the generation of strong runaway beams during disruptions of largetokamak devices, including TFTR, JET, DIIID and ITER, is performed based on typical operating parameters of these devices and the presently accepted disruption model. The main results include: (1) In the existing devices, the evaporative preicer'' process by itself can lead to sizable runaway beams in disruptions of high-current-medium-to-low-ne discharges. In ITER, such runaways are expected mainly for discharges with ne values sizably smaller than the projected typical ones. (2) Runaway generation also may occur during post-thermal-quench period through the untrapping of trapped hot-thermal electrons remaining from the pre-thermal-quench plasma; this process may be directly important in particular in disruptions of high-T[sub e] discharges with details depending on the time required for reclosure of the magnetic surfaces. Both processes (1) and (2) will occur and be completed mostly during the initial few 100 [mu]sec after the thermal quench. (3) Subsequently, close collisions of runaways with cold plasma electrons generally will lead to an exponential growth ( avalanching'') of runaway populations generated by processes (1) and/or (2) and/or others; this process will be effective in particular during the current quench phase and will continue until the resulting runaway beam will carry essentially all of the remaining discharge current. In presently existing devices, possible avalanche factors of up to 10[sup 2]--10[sup 5] may be expected; in ITER, avalanche factors of up to 10[sup 10]--10[sup 15] -- if not properly suppressed -- are expected to lead to strong runaway beams in most disruptions, except those at particularly high densities. At the same time, avalanching will shift the main part of their energy spectrum down to relatively low energies around 10--20 MeV, and may sizably change the spatial distribution of the runaways.

  1. Evaluation of potential runaway generation in large-tokamak disruptions

    SciTech Connect

    Fleischmann, H.H.; Zweben, S.J. |

    1993-06-01

    A detailed evaluation of various potential mechanisms for the generation of strong runaway beams during disruptions of largetokamak devices, including TFTR, JET, DIIID and ITER, is performed based on typical operating parameters of these devices and the presently accepted disruption model. The main results include: (1) In the existing devices, the evaporative ``preicer`` process by itself can lead to sizable runaway beams in disruptions of high-current-medium-to-low-ne discharges. In ITER, such runaways are expected mainly for discharges with ne values sizably smaller than the projected typical ones. (2) Runaway generation also may occur during post-thermal-quench period through the untrapping of trapped hot-thermal electrons remaining from the pre-thermal-quench plasma; this process may be directly important in particular in disruptions of high-T{sub e} discharges with details depending on the time required for reclosure of the magnetic surfaces. Both processes (1) and (2) will occur and be completed mostly during the initial few 100 {mu}sec after the thermal quench. (3) Subsequently, close collisions of runaways with cold plasma electrons generally will lead to an exponential growth (``avalanching``) of runaway populations generated by processes (1) and/or (2) and/or others; this process will be effective in particular during the current quench phase and will continue until the resulting runaway beam will carry essentially all of the remaining discharge current. In presently existing devices, possible avalanche factors of up to 10{sup 2}--10{sup 5} may be expected; in ITER, avalanche factors of up to 10{sup 10}--10{sup 15} -- if not properly suppressed -- are expected to lead to strong runaway beams in most disruptions, except those at particularly high densities. At the same time, avalanching will shift the main part of their energy spectrum down to relatively low energies around 10--20 MeV, and may sizably change the spatial distribution of the runaways.

  2. Liquefaction Potential of Unsaturated Nevada Sand at Different Initial Conditions

    NASA Astrophysics Data System (ADS)

    Xu, Jiting

    It has been tacitly assumed that liquefaction does not occur in unsaturated soils during seismic events, because pore air behaves as a cushion and excess pore water pressure is difficult to accumulate. During recent earthquakes, some slopes composed of unsaturated soils experienced large deformation similar to fluid flow. One explanation for this phenomenon is that the unsaturated slopes completely lost their effective stress and reached a state of liquefaction. The field observation shows controversial phenomenon against current understanding on soil liquefaction. This work was motivated to solve this controversy by experimentally studying the following two questions: 1) are unsaturated soils liquefiable? and 2) how do the initial conditions, including relative density, effective confining pressure, and degree of saturation affect the liquefaction potential of unsaturated soils? To answer the above questions, a series of strain-controlled undrained cyclic loading triaxial tests on saturated and unsaturated Nevada sand were conducted. The index properties studied included particle size distribution, maximum and minimum void ratios, and specific gravity. To provide data for future numerical modeling on unsaturated Nevada sand, hysteretic soil water characteristics curves under different relative densities were also measured. For triaxial tests on saturated Nevada sand, the effects of initial relative density (i.e. Dr=30%, 50%, and 70%) and effective confining pressure (i.e. s'c0 =50 kPa, 100 kPa, and 200 kPa) on soil liquefaction were studied. For unsaturated soil tests, besides initial relative density (Dr=50%) and effective confining pressure ( s'c0 =100 kPa), the effects of initial degree of saturation (S r0=90%, 95%) on liquefaction were also investigated. For saturated Nevada sand, the liquefaction potential decreased with an increase of relative density and effective confining pressure. When the other initial conditions were the same, the cycles needed to make

  3. On hemispheric differences in evoked potentials to speech stimuli

    NASA Technical Reports Server (NTRS)

    Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

    1975-01-01

    Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

  4. Murine and human CFTR exhibit different sensitivities to CFTR potentiators.

    PubMed

    Cui, Guiying; McCarty, Nael A

    2015-10-01

    Development of therapeutic molecules with clinical efficacy as modulators of defective CFTR includes efforts to identify potentiators that can overcome or repair the gating defect in mutant CFTR channels. This has taken a great leap forward with the identification of the potentiator VX-770, now available to patients as "Kalydeco." Other small molecules with different chemical structure also are capable of potentiating the activity of either wild-type or mutant CFTR, suggesting that there are features of the protein that may be targeted to achieve stimulation of channel activity by structurally diverse compounds. However, neither the mechanisms by which these compounds potentiate mutant CFTR nor the site(s) where these compounds bind have been identified. This knowledge gap partly reflects the lack of appropriate experimental models to provide clues toward the identification of binding sites. Here, we have compared the channel behavior and response to novel and known potentiators of human CFTR (hCFTR) and murine (mCFTR) expressed in Xenopus oocytes. Both hCFTR and mCFTR were blocked by GlyH-101 from the extracellular side, but mCFTR activity was increased with GlyH-101 applied directly to the cytoplasmic side. Similarly, glibenclamide only exhibited a blocking effect on hCFTR but both blocked and potentiated mCFTR in excised membrane patches and in intact oocytes. The clinically used CFTR potentiator VX-770 transiently increased hCFTR by ∼13% but potentiated mCFTR significantly more strongly. Our results suggest that mCFTR pharmacological sensitivities differ from hCFTR, which will provide a useful tool for identifying the binding sites and mechanism for these potentiators. PMID:26209275

  5. Inter-point procrustes: identifying regional and large differences in 3D anatomical shapes.

    PubMed

    Lekadir, Karim; Frangi, Alejandro F; Yang, Guang-Zhong

    2012-01-01

    This paper presents a new approach for the robust alignment and interpretation of 3D anatomical structures with large and localized shape differences. In such situations, existing techniques based on the well-known Procrustes analysis can be significantly affected due to the introduced non-Gaussian distribution of the residuals. In the proposed technique, influential points that induce large dissimilarities are identified and displaced with the aim to obtain an intermediate template with an improved distribution of the residuals. The key element of the algorithm is the use of pose invariant shape variables to robustly guide both the influential point detection and displacement steps. The intermediate template is then used as the basis for the estimation of the final pose parameters between the source and destination shapes, enabling to effectively highlight the regional differences of interest. The validation using synthetic and real datasets of different morphologies demonstrates robustness up-to 50% regional differences and potential for shape classification. PMID:23286119

  6. Large and Small Dendritic Spines Serve Different Interacting Functions in Hippocampal Synaptic Plasticity and Homeostasis

    PubMed Central

    Paulin, Joshua J. W.; Haslehurst, Peter; Fellows, Alexander D.; Liu, Wenfei; Jackson, Joshua D.; Joel, Zelah; Cummings, Damian M.; Edwards, Frances A.

    2016-01-01

    The laying down of memory requires strong stimulation resulting in specific changes in synaptic strength and corresponding changes in size of dendritic spines. Strong stimuli can also be pathological, causing a homeostatic response, depressing and shrinking the synapse to prevent damage from too much Ca2+ influx. But do all types of dendritic spines serve both of these apparently opposite functions? Using confocal microscopy in organotypic slices from mice expressing green fluorescent protein in hippocampal neurones, the size of individual spines along sections of dendrite has been tracked in response to application of tetraethylammonium. This strong stimulus would be expected to cause both a protective homeostatic response and long-term potentiation. We report separation of these functions, with spines of different sizes reacting differently to the same strong stimulus. The immediate shrinkage of large spines suggests a homeostatic protective response during the period of potential danger. In CA1, long-lasting growth of small spines subsequently occurs consolidating long-term potentiation but only after the large spines return to their original size. In contrast, small spines do not change in dentate gyrus where potentiation does not occur. The separation in time of these changes allows clear functional differentiation of spines of different sizes. PMID:26881123

  7. Metabolomic Analyses of Leishmania Reveal Multiple Species Differences and Large Differences in Amino Acid Metabolism

    PubMed Central

    Wang, Lijie; Zhang, Tong; Watson, David G.; Silva, Ana Marta; Coombs, Graham H.

    2015-01-01

    Comparative genomic analyses of Leishmania species have revealed relatively minor heterogeneity amongst recognised housekeeping genes and yet the species cause distinct infections and pathogenesis in their mammalian hosts. To gain greater information on the biochemical variation between species, and insights into possible metabolic mechanisms underpinning visceral and cutaneous leishmaniasis, we have undertaken in this study a comparative analysis of the metabolomes of promastigotes of L. donovani, L. major and L. mexicana. The analysis revealed 64 metabolites with confirmed identity differing 3-fold or more between the cell extracts of species, with 161 putatively identified metabolites differing similarly. Analysis of the media from cultures revealed an at least 3-fold difference in use or excretion of 43 metabolites of confirmed identity and 87 putatively identified metabolites that differed to a similar extent. Strikingly large differences were detected in their extent of amino acid use and metabolism, especially for tryptophan, aspartate, arginine and proline. Major pathways of tryptophan and arginine catabolism were shown to be to indole-3-lactate and arginic acid, respectively, which were excreted. The data presented provide clear evidence on the value of global metabolomic analyses in detecting species-specific metabolic features, thus application of this technology should be a major contributor to gaining greater understanding of how pathogens are adapted to infecting their hosts. PMID:26368322

  8. Intense THz Pulses with large ponderomotive potential generated from large aperture photoconductive antennas.

    PubMed

    Ropagnol, X; Khorasaninejad, M; Raeiszadeh, M; Safavi-Naeini, S; Bouvier, M; Côté, C Y; Laramée, A; Reid, M; Gauthier, M A; Ozaki, T

    2016-05-30

    We report the generation of free space terahertz (THz) pulses with energy up to 8.3 ± 0.2 µJ from an encapsulated interdigitated ZnSe Large Aperture Photo-Conductive Antenna (LAPCA). An aperture of 12.2 cm2 is illuminated using a 400 nm pump laser with multi-mJ energies at 10 Hz repetition rate. The calculated THz peak electric field is 331 ± 4 kV/cm with a spectrum characterized by a median frequency of 0.28 THz. Given its relatively low frequency, this THz field will accelerate charged particles efficiently having very large ponderomotive energy of 15 ± 1 eV for electrons in vacuum. The scaling of the emission is studied with respect to the dimensions of the antenna, and it is observed that the capacitance of the LAPCA leads to a severe decrease in and distortion of the biasing voltage pulse, fundamentally limiting the maximum applied bias field and consequently the maximum energy of the radiated THz pulses. In order to demonstrate the advantages of this source in the strong field regime, an open-aperture Z-scan experiment was performed on n-doped InGaAs, which showed significant absorption bleaching. PMID:27410061

  9. FDIPS: Finite Difference Iterative Potential-field Solver

    NASA Astrophysics Data System (ADS)

    Toth, Gabor; van der Holst, Bartholomeus; Huang, Zhenguang

    2016-06-01

    FDIPS is a finite difference iterative potential-field solver that can generate the 3D potential magnetic field solution based on a magnetogram. It is offered as an alternative to the spherical harmonics approach, as when the number of spherical harmonics is increased, using the raw magnetogram data given on a grid that is uniform in the sine of the latitude coordinate can result in inaccurate and unreliable results, especially in the polar regions close to the Sun. FDIPS is written in Fortran 90 and uses the MPI library for parallel execution.

  10. Scaling differences between large interplate and intraplate earthquakes

    NASA Technical Reports Server (NTRS)

    Scholz, C. H.; Aviles, C. A.; Wesnousky, S. G.

    1985-01-01

    A study of large intraplate earthquakes with well determined source parameters shows that these earthquakes obey a scaling law similar to large interplate earthquakes, in which M sub o varies as L sup 2 or u = alpha L where L is rupture length and u is slip. In contrast to interplate earthquakes, for which alpha approximately equals 1 x .00001, for the intraplate events alpha approximately equals 6 x .0001, which implies that these earthquakes have stress-drops about 6 times higher than interplate events. This result is independent of focal mechanism type. This implies that intraplate faults have a higher frictional strength than plate boundaries, and hence, that faults are velocity or slip weakening in their behavior. This factor may be important in producing the concentrated deformation that creates and maintains plate boundaries.

  11. Reconstruction of the local inflationary potential with different correlation levels

    NASA Astrophysics Data System (ADS)

    Di Marco, A.; Cabella, P.; Vittorio, N.

    2016-02-01

    We review the puzzles of the standard Big Bang model and cosmic inflation as their possible solutions. The relation between inflation and the spectra of the cosmological perturbations is emphasized. In particular we focus on the local reconstruction of the shape of the inflationary potential from observations and the consequences of a direct detection of cosmological gravitational waves, exploring different correlation levels between the spectral index ns and the tensor-to-scalar ratio r of the primordial perturbations.

  12. Differences in Plasma Conditions Among 85 Large Coronal Holes

    NASA Astrophysics Data System (ADS)

    Miralles, M. P.; Cranmer, S. R.; Kohl, J. L.

    2004-05-01

    We have measured ultraviolet spectroscopic parameters as a function of heliocentric distance for more than 85 coronal holes, in order to characterize the physical properties of coronal holes at different phases of the solar cycle. The Ultraviolet Coronagraph Spectrometer (UVCS) aboard SOHO was used to observed O VI (103.2 and 103.7 nm) and H I Lyman alpha (121.6 nm) emission lines to determine kinetic temperatures, average densities, and outflow speeds in coronal holes. UVCS observations provide unique information on the heating and acceleration processes in the corona. Our previous analyses of UVCS observations have shown that solar minimum (polar) and solar maximum (equatorial) coronal holes produce different acceleration profiles and have different oxygen kinetic temperatures. We also examine the differences in the characteristics of representative coronal holes producing a variety of high-speed conditions (550-800 km/s) at 1 AU. These analyses provide limits on the coronal plasma properties and put constraints on the physical processes that are responsible for the heating of the extended corona and the acceleration of the solar wind. This work is supported by NASA under Grant NAG5-12865 to the Smithsonian Astrophysical Observatory, by the Italian Space Agency and by PRODEX (Swiss contribution).

  13. Injury Differences Between Small and Large Overlap Frontal Crashes

    PubMed Central

    Hallman, Jason J.; Yoganandan, Narayan; Pintar, Frank A.; Maiman, Dennis J.

    2011-01-01

    Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction. PMID:22105392

  14. Linear polarization difference imaging and its potential applications.

    PubMed

    Nan, Zeng; Xiaoyu, Jiang; Qiang, Gao; Yonghong, He; Hui, Ma

    2009-12-10

    We demonstrate a novel linear polarization imaging technique and its potential application in dermatology. This technique records a series of images corresponding to different combinations of illumination and detection polarization and calculates intensity differences between orthogonal detection polarizations pixel by pixel. Fitting the polarization difference data to an analytical expression of the incident and detection polarization angles results in two new parameters, G and (phi3)/2. It is shown that G is strongly correlated to the order of alignment of the fibrous structure in the sample, and (phi3)/2 represents the angle of orientation of the fibers. Preliminary clinical testing implies that this method may be applied for medical diagnosis of skin diseases. PMID:20011013

  15. Direct measurement of lower atmospheric vertical potential differences

    NASA Technical Reports Server (NTRS)

    Holzworth, R. H.; Dazey, M. H.; Schnauss, E. R.; Youngbluth, O.

    1981-01-01

    A high impedance system has been developed to make direct measurements of the atmospheric potential difference up to several thousand feet. A tethered balloon flown from Wallops Island, Virginia was used to loft a high voltage, insulated wire and a conducting collector in a test flight to 550 meters for two days of experiments in October 1980. The balloon was equipped with a payload to measure exact altitude, wind speed and direction, and other meteorological parameters. Electric potentials of 170,000 volts at 550 meters were measured. The collected currents which could be drawn through the wire by grounding the lower end were in the 10 microamp range indicating a system impedance of about 10 to the 10th ohms. This paper describes the apparatus and details of these measurements.

  16. Improved finite difference schemes for transonic potential calculations

    NASA Technical Reports Server (NTRS)

    Hafez, M.; Osher, S.; Whitlow, W., Jr.

    1984-01-01

    Engquist and Osher (1980) have introduced a finite difference scheme for solving the transonic small disturbance equation, taking into account cases in which only compression shocks are admitted. Osher et al. (1983) studied a class of schemes for the full potential equation. It is proved that these schemes satisfy a new discrete 'entropy inequality' which rules out expansion shocks. However, the conducted analysis is restricted to steady two-dimensional flows. The present investigation is concerned with the adoption of a heuristic approach. The full potential equation in conservation form is solved with the aid of a modified artificial density method, based on flux biasing. It is shown that, with the current scheme, expansion shocks are not possible.

  17. Kinematic morphology of large-scale structure: evolution from potential to rotational flow

    SciTech Connect

    Wang, Xin; Szalay, Alex; Aragón-Calvo, Miguel A.; Neyrinck, Mark C.; Eyink, Gregory L.

    2014-09-20

    As an alternative way to describe the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of the characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. We show that this tool, first introduced in turbulence two decades ago, is very useful for understanding the evolution of the cosmic web structure, and in classifying its morphology. Before shell crossing, different categories of potential flow are highly associated with the cosmic web structure because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between the cosmic web and vorticity direction for various vortical flows. Incorporating shell crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of the phenomena relating to the internal structure of the three-dimensional invariant space.

  18. Kinematic Morphology of Large-scale Structure: Evolution from Potential to Rotational Flow

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Szalay, Alex; Aragón-Calvo, Miguel A.; Neyrinck, Mark C.; Eyink, Gregory L.

    2014-09-01

    As an alternative way to describe the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of the characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. We show that this tool, first introduced in turbulence two decades ago, is very useful for understanding the evolution of the cosmic web structure, and in classifying its morphology. Before shell crossing, different categories of potential flow are highly associated with the cosmic web structure because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between the cosmic web and vorticity direction for various vortical flows. Incorporating shell crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of the phenomena relating to the internal structure of the three-dimensional invariant space.

  19. Collision between immiscible drops with large surface tension difference

    NASA Astrophysics Data System (ADS)

    Arienti, Marco; Li, Xiaoyi; Soteriou, Marios; Sussman, Mark

    2009-11-01

    Immiscible drop collision, as occurring in fuel-oxidizer sprays or in the release of certain fire-extinguishing agents, tends to exhibit a much richer behavior with respect to miscible drops collision thanks to the formation of a liquid-liquid interface during impact. For instance, in near-head-on diesel-water drop collisions, ``overlaying'' may occur in which the diesel oil flows from the collision point around the water drop to gather at the opposite location of the drop. To simulate this class of multi-material flows, the combined volume-of-fluid / level set methodology that sharply captures a single liquid-gas interface (Sussman et al, J. of Comp. Phys., 2007) needs to be duplicated for a second, independent interface. In this presentation, we will show that simulation results are not affected by the reconstruction order of the interfaces, as in other surface capturing methods. We will also propose different numerical solutions to treat surface tension in the triple point computational cells, and examine the characteristics of the flow developing at the contact line between the two liquids and air in overlaying head-on collisions.

  20. Nasal Potential Difference in Cystic Fibrosis considering Severe CFTR Mutations

    PubMed Central

    Ng, Ronny Tah Yen; Marson, Fernando Augusto de Lima; Ribeiro, Jose Dirceu; Ribeiro, Antonio Fernando; Bertuzzo, Carmen Silvia; Ribeiro, Maria Angela Gonçalves de Oliveira; Severino, Silvana Dalge; Sakano, Eulalia

    2015-01-01

    The gold standard for diagnosing cystic fibrosis (CF) is a sweat chloride value above 60 mEq/L. However, this historical and important tool has limitations; other techniques should be studied, including the nasal potential difference (NPD) test. CFTR gene sequencing can identify CFTR mutations, but this method is time-consuming and too expensive to be used in all CF centers. The present study compared CF patients with two classes I-III CFTR mutations (10 patients) (G1), CF patients with classes IV-VI CFTR mutations (five patients) (G2), and 21 healthy subjects (G3). The CF patients and healthy subjects also underwent the NPD test. A statistical analysis was performed using the Mann-Whitney, Kruskal-Wallis, χ2, and Fisher's exact tests, α = 0.05. No differences were observed between the CF patients and healthy controls for the PDMax, Δamiloride, and Δchloride + free + amiloride markers from the NPD test. For the finger value, a difference between G2 and G3 was described. The Wilschanski index values were different between G1 and G3. In conclusion, our data showed that NPD is useful for CF diagnosis when classes I-III CFTR mutations are screened. However, if classes IV-VI are considered, the NPD test showed an overlap in values with healthy subjects. PMID:25667564

  1. Potential theory for shock reflection by a large-angle wedge.

    PubMed

    Chen, Gui-Qiang; Feldman, Mikhail

    2005-10-25

    When a plane shock hits a wedge head on, it experiences a reflection, and then a self-similar reflected shock moves outward as the original shock moves forward in time. Experimental, computational, and asymptotic analysis has shown that various patterns of reflected shocks may occur, including regular and Mach reflection. However, most fundamental issues for shock reflection phenomena have not been understood, such as the transition among the different patterns of shock reflection; therefore, it is essential to establish a global existence and stability theory for shock reflection. On the other hand, there has been no rigorous mathematical result on the global existence and stability of solutions to shock reflection, especially for potential flow, which has widely been used in aerodynamics. The theoretical problems involve several challenging difficulties in the analysis of nonlinear partial differential equations including elliptic-hyperbolic mixed type, free-boundary problems, and corner singularity, especially when an elliptic degenerate curve meets a free boundary. Here we develop a potential theory to overcome these difficulties and to establish the global existence and stability of solutions to shock reflection by a large-angle wedge for potential flow. The techniques and ideas developed will be useful to other nonlinear problems involving similar difficulties. PMID:16230619

  2. Normalized rupture potential for small and large earthquakes along the Pacific Plate off Japan

    NASA Astrophysics Data System (ADS)

    Tormann, Thessa; Wiemer, Stefan; Enescu, Bogdan; Woessner, Jochen

    2016-07-01

    We combine temporal variability in local seismic activity rates and size distributions to estimate the evolution of a Gutenberg-Richter-based metric, the normalized rupture potential (NRP), comparing differences between smaller and larger earthquakes. For the Pacific Plate off Japan, we study both complex spatial patterns and how they evolve over the last 18 years, and more detailed temporal characteristics in a simplified spatial selection, i.e., inside and outside the high-slip zone of the 2011 M9 Tohoku earthquake. We resolve significant changes, in particular an immediate NRP increase for large events prior to the Tohoku event in the subsequent high-slip patch, a very rapid decrease inside this high-stress-release area coupled with a lasting increase of NRP in the immediate surroundings. Even in the center of the Tohoku rupture, the NRP for large magnitudes has not dropped below the 12 year average and is not significantly different from conditions a decade before the M9 event.

  3. Visual Evoked Potentials: Normative Values and Gender Differences

    PubMed Central

    Sharma, Ruby; Singh, K.D.; Kumar, Avnish

    2015-01-01

    Introduction Visual evoked potentials (VEP) are used to assess the visual pathways through the optic nerves and brain. A normal VEP response to a pattern-reversal stimulus is a positive mid occipital peak that occurs at a mean latency of 100 ms. VEP may be affected by variety of physiological factors including age, sex, visual acuity and pupillary size. Aims and Objectives The present study was performed on healthy medical students to determine the normative values and to investigate the effect of sex and anthropometric parameters on visual evoked potentials. Materials and Methods The study was conducted on 100 healthy medical students of Government Medical College, Patiala in the age group of 17-20 years, in which there were 50 males and 50 females. The anthropometric parameters including age, height, weight, BMI, BSA and Head circumference were recorded in all the subjects. VEP was recorded with a PC based, 2 channel, RMS EMG EP mark II machine and standard silver-silver chloride disc electrodes. A VEP monitor displaying checker board was used to give the pattern reversal stimulus. The VEP parameters recorded were latencies to N70, P100 and N155 waves, and peak to peak amplitude of P100 wave. Results Our results showed that the latencies of N70, P100 and N155 waves were significantly longer in males as compared to females. The amplitude of P100 wave was higher in females in both left and right eye as compared to males. No significant correlation was found between VEP parameters and head circumference in both male and female subjects in our study. Conclusion Gender is an important variable affecting the VEP. The exact reason of gender difference is not clear, but it may be related to anatomical or endocrinal differences in the two sexes. PMID:26393122

  4. An International Randomized Multicenter Comparison of Nasal Potential Difference Techniques

    PubMed Central

    Solomon, George M.; Konstan, Michael W.; Wilschanski, Michael; Billings, Joanne; Sermet-Gaudelus, Isabelle; Accurso, Frank; Vermeulen, François; Levin, Elina; Hathorne, Heather; Reeves, Ginger; Sabbatini, Gina; Hill, Aubrey; Mayer-Hamblett, Nicole; Ashlock, Melissa; Clancy, John Paul

    2010-01-01

    Background: The transepithelial nasal potential difference (NPD) is used to assess cystic fibrosis transmembrane conductance regulator (CFTR) activity. Unreliability, excessive artifacts, and lack of standardization of current testing systems can compromise its use as a diagnostic test and outcome measure for clinical trials. Methods: To determine whether a nonperfusing (agar gel) nasal catheter for NPD measurement is more reliable and less susceptible to artifacts than a continuously perfusing nasal catheter, we performed a multicenter, randomized, crossover trial comparing a standardized NPD protocol using an agar nasal catheter with the same protocol using a continuously perfusing catheter. The data capture technique was identical in both protocols. A total of 26 normal adult subjects underwent NPD testing at six different centers. Results: Artifact frequency was reduced by 75% (P < .001), and duration was less pronounced using the agar catheter. The measurement of sodium conductance was similar between the two catheter methods, but the agar catheter demonstrated significantly greater CFTR-dependent hyperpolarization, because Δ zero Cl- + isoproterenol measurements were significantly more hyperpolarized with the agar catheter (224.2 ± 12.9 mV with agar vs 18.2 ± 9.1 mV with perfusion, P < .05). Conclusions: The agar nasal catheter approach demonstrates superior reliability compared with the perfusion nasal catheter method for measurement of NPD. This nonperfusion catheter method should be considered for adoption as a standardized protocol to monitor CFTR activity in clinical trials. PMID:20472865

  5. Chiral symmetry restoration at large chemical potential in strongly coupled SU(N) gauge theories

    SciTech Connect

    Tomboulis, E. T.

    2013-12-15

    We show that at sufficiently large chemical potential SU(N) lattice gauge theories in the strong coupling limit with staggered fermions are in a chirally symmetric phase. The proof employs a polymer cluster expansion which exploits the anisotropy between timelike and spacelike directions in the presence of a quark chemical potential μ. The expansion is shown to converge in the infinite volume limit at any temperature for sufficiently large μ. All expectations of chirally non-invariant local fermion operators vanish identically, or, equivalently, their correlations cluster exponentially, within the expansion. The expansion itself may serve as a computational tool at large μ and strong coupling.

  6. Biomass Potentials in Different Maintenance Scenarios of Satoyama Woodlands

    NASA Astrophysics Data System (ADS)

    Terada, T.

    2012-04-01

    Woodlands near human settlements often have long histories of providing people with fuelwood and other organic materials. In Japan, these woodlands are called satoyama. While satoyama woodlands were historically coppiced to provide an essential source of fuelwood, many have been developed into residential areas as a result of the introduction of fossil fuels beginning in the 1960's. Remaining satoyamas were simply abandoned due to the loss of economic value from fuelwood. This has resulted in a loss of other satoyama-related functions such as their ecological function. In response to the abandonment of satoyamas, thousands of volunteer groups have formed since the 1990's to restore satoyama woodlands. However, in spite of the importance of grassroots volunteers, their actual activities are limited in spatial extent due to shortages of manpower, time, and maintenance skill. This suggests that more substantial incentives are necessary, if maintenance of satoyama woodlands is to be extended. This study focused on an increased attention of biomass enegy utilization from satoyama trees as a promising incentive, and estimated biomass potentials in different maintenance scenarios of satoyama woodlands through a case study site in peri-urban Tokyo. This study set four maintenance scenarios; a) ground cover removal, b) light-thinning, c) intensive-thinning, and d) rotational coppicing. Based on the scenarios, the amount of biomass obtained, bioenergy generated, and carbon reduced were estimated respectively by the combination of conducting tree measurement and applying a long-term forest dynamics estimation model. Since there is tradeoff between CO2 reduction through woodenergy utilization and CO2 fixation by standing trees, these two variables were analyzed in tandem. The scenario that produces the most woody biomass was rotational coppicing, the maintenance scenario which also mimics historical management regimes. Despite the lowest potential of CO2 fixation by standing

  7. Cryptococcus Strains with Different Pathogenic Potentials Have Diverse Protein Secretomes

    PubMed Central

    Campbell, Leona T.; Simonin, Anna R.; Chen, Cuilan; Ferdous, Jannatul; Padula, Matthew P.; Harry, Elizabeth; Hofer, Markus; Campbell, Iain L.

    2015-01-01

    Secreted proteins are the frontline between the host and pathogen. In mammalian hosts, secreted proteins enable invasive infection and can modulate the host immune response. Cryptococcosis, caused by pathogenic Cryptococcus species, begins when inhaled infectious propagules establish to produce pulmonary infection, which, if not resolved, can disseminate to the central nervous system to cause meningoencephalitis. Strains of Cryptococcus species differ in their capacity to cause disease, and the mechanisms underlying this are not well understood. To investigate the role of secreted proteins in disease, we determined the secretome for three genome strains of Cryptococcus species, including a hypovirulent and a hypervirulent strain of C. gattii and a virulent strain of C. neoformans. Sixty-seven unique proteins were identified, with different numbers and types of proteins secreted by each strain. The secretomes of the virulent strains were largely limited to proteolytic and hydrolytic enzymes, while the hypovirulent strain had a diverse secretome, including non-conventionally secreted canonical cytosolic and immunogenic proteins that have been implicated in virulence. The hypovirulent strain cannot establish pulmonary infection in a mouse model, but strains of this genotype have caused human meningitis. To directly test brain infection, we used intracranial inoculation and found that the hypovirulent strain was substantially more invasive than its hypervirulent counterpart. We suggest that immunogenic proteins secreted by this strain invoke a host response that limits pulmonary infection but that there can be invasive growth and damage if infection reaches the brain. Given their known role in virulence, it is possible that non-conventionally secreted proteins mediate this process. PMID:25841021

  8. Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions.

    PubMed

    Xiao, Jun; Wang, Ya-Feng; Shi, Peng; Yang, Lei; Chen, Li-Ding

    2014-11-01

    Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant

  9. Modelling potential changes in marine biogeochemistry due to large-scale offshore wind farms

    NASA Astrophysics Data System (ADS)

    van der Molen, Johan; Rees, Jon; Limpenny, Sian

    2013-04-01

    Large-scale renewable energy generation by offshore wind farms may lead to changes in marine ecosystem processes through the following mechanism: 1) wind-energy extraction leads to a reduction in local surface wind speeds; 2) these lead to a reduction in the local wind wave height; 3) as a consequence there's a reduction in SPM resuspension and concentrations; 4) this results in an improvement in under-water light regime, which 5) may lead to increased primary production, which subsequently 6) cascades through the ecosystem. A three-dimensional coupled hydrodynamics-biogeochemistry model (GETM_ERSEM) was used to investigate this process for a hypothetical wind farm in the central North Sea, by running a reference scenario and a scenario with a 10% reduction (as was found in a case study of a small farm in Danish waters) in surface wind velocities in the area of the wind farm. The ERSEM model included both pelagic and benthic processes. The results showed that, within the farm area, the physical mechanisms were as expected, but with variations in the magnitude of the response depending on the ecosystem variable or exchange rate between two ecosystem variables (3-28%, depending on variable/rate). Benthic variables tended to be more sensitive to the changes than pelagic variables. Reduced, but noticeable changes also occurred for some variables in a region of up to two farm diameters surrounding the wind farm. An additional model run in which the 10% reduction in surface wind speed was applied only for wind speeds below the generally used threshold of 25 m/s for operational shut-down showed only minor differences from the run in which all wind speeds were reduced. These first results indicate that there is potential for measurable effects of large-scale offshore wind farms on the marine ecosystem, mainly within the farm but for some variables up to two farm diameters away. However, the wave and SPM parameterisations currently used in the model are crude and need to be

  10. Artificial Boundary Conditions Based on the Difference Potentials Method

    NASA Technical Reports Server (NTRS)

    Tsynkov, Semyon V.

    1996-01-01

    While numerically solving a problem initially formulated on an unbounded domain, one typically truncates this domain, which necessitates setting the artificial boundary conditions (ABC's) at the newly formed external boundary. The issue of setting the ABC's appears to be most significant in many areas of scientific computing, for example, in problems originating from acoustics, electrodynamics, solid mechanics, and fluid dynamics. In particular, in computational fluid dynamics (where external problems present a wide class of practically important formulations) the proper treatment of external boundaries may have a profound impact on the overall quality and performance of numerical algorithms. Most of the currently used techniques for setting the ABC's can basically be classified into two groups. The methods from the first group (global ABC's) usually provide high accuracy and robustness of the numerical procedure but often appear to be fairly cumbersome and (computationally) expensive. The methods from the second group (local ABC's) are, as a rule, algorithmically simple, numerically cheap, and geometrically universal; however, they usually lack accuracy of computations. In this paper we first present a survey and provide a comparative assessment of different existing methods for constructing the ABC's. Then, we describe a relatively new ABC's technique of ours and review the corresponding results. This new technique, in our opinion, is currently one of the most promising in the field. It enables one to construct such ABC's that combine the advantages relevant to the two aforementioned classes of existing methods. Our approach is based on application of the difference potentials method attributable to V. S. Ryaben'kii. This approach allows us to obtain highly accurate ABC's in the form of certain (nonlocal) boundary operator equations. The operators involved are analogous to the pseudodifferential boundary projections first introduced by A. P. Calderon and then

  11. Reduction of the field-aligned potential drop in the polar cap during large geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Kitamura, N.; Seki, K.; Nishimura, Y.; Hori, T.; Terada, N.; Ono, T.; Strangeway, R. J.

    2013-12-01

    We have studied photoelectron flows and the inferred field-aligned potential drop in the polar cap during 5 large geomagnetic storms that occurred in the periods when the photoelectron observations in the polar cap were available near the apogee of the FAST satellite (~4000 km) at solar maximum, and the footprint of the satellite paths in the polar cap was under sunlit conditions most of the time. In contrast to the ~20 V potential drop during geomagnetically quiet periods at solar maximum identified by Kitamura et al. [JGR, 2012], the field-aligned potential drop frequently became smaller than ~5 V during the main and early recovery phases of the large geomagnetic storms. Because the potential acts to inhibit photoelectron escape, this result indicates that the corresponding acceleration of ions by the field-aligned potential drop in the polar cap and the lobe region is smaller during the main and early recovery phases of large geomagnetic storms compared to during geomagnetically quiet periods. Under small field-aligned current conditions, the number flux of outflowing ions should be nearly equal to the net escaping electron number flux. Since ions with large flux originating from the cusp/cleft ionosphere convect into the polar cap during geomagnetic storms [e.g., Kitamura et al., JGR, 2010], the net escaping electron number flux should increase to balance the enhanced ion outflows. The magnitude of the field-aligned potential drop would be reduced to let a larger fraction of photoelectrons escape.

  12. Highlighting Relationships of a Smartphone's Social Ecosystem in Potentially Large Investigations.

    PubMed

    Andriotis, Panagiotis; Oikonomou, George; Tryfonas, Theo; Li, Shancang

    2016-09-01

    Social media networks are becoming increasingly popular because they can satisfy diverse needs of individuals (both personal and professional). Modern mobile devices are empowered with increased capabilities, taking advantage of the technological progress that makes them smarter than their predecessors. Thus, a smartphone user is not only the phone owner, but also an entity that may have different facets and roles in various social media networks. We believe that these roles can be aggregated in a single social ecosystem, which can be derived by the smartphone. In this paper, we present our concept of the social ecosystem in contemporary devices and we attempt to distinguish the different communities that occur from the integration of social networking in our lives. In addition, we propose techniques to highlight major actors within the ecosystem. Moreover, we demonstrate our suggested visualization scheme, which illustrates the linking of entities that live in separate communities using data taken from the smartphone. Finally, we extend our concept to include various parallel ecosystems during potentially large investigations and we link influential entities in a vertical fashion. We particularly examine cases where data aggregation is performed by specific applications, producing volumes of textual data that can be analyzed with text mining methods. Our analysis demonstrates the risks of the rising "bring your own device" trend in enterprise environments. PMID:26316287

  13. Assessment of economically optimal water management and geospatial potential for large-scale water storage

    NASA Astrophysics Data System (ADS)

    Weerasinghe, Harshi; Schneider, Uwe A.

    2010-05-01

    Assessment of economically optimal water management and geospatial potential for large-scale water storage Weerasinghe, Harshi; Schneider, Uwe A Water is an essential but limited and vulnerable resource for all socio-economic development and for maintaining healthy ecosystems. Water scarcity accelerated due to population expansion, improved living standards, and rapid growth in economic activities, has profound environmental and social implications. These include severe environmental degradation, declining groundwater levels, and increasing problems of water conflicts. Water scarcity is predicted to be one of the key factors limiting development in the 21st century. Climate scientists have projected spatial and temporal changes in precipitation and changes in the probability of intense floods and droughts in the future. As scarcity of accessible and usable water increases, demand for efficient water management and adaptation strategies increases as well. Addressing water scarcity requires an intersectoral and multidisciplinary approach in managing water resources. This would in return safeguard the social welfare and the economical benefit to be at their optimal balance without compromising the sustainability of ecosystems. This paper presents a geographically explicit method to assess the potential for water storage with reservoirs and a dynamic model that identifies the dimensions and material requirements under an economically optimal water management plan. The methodology is applied to the Elbe and Nile river basins. Input data for geospatial analysis at watershed level are taken from global data repositories and include data on elevation, rainfall, soil texture, soil depth, drainage, land use and land cover; which are then downscaled to 1km spatial resolution. Runoff potential for different combinations of land use and hydraulic soil groups and for mean annual precipitation levels are derived by the SCS-CN method. Using the overlay and decision tree algorithms

  14. Electrodiffusiophoresis of a large-zeta-potential particle in weak fields.

    PubMed

    Tricoli, Vincenzo; Orsini, Gabriele

    2015-10-21

    The electrodiffusiophoresis of a large-zeta-potential (ζ) particle in weak fields is investigated. In this large-ζ regime, Debye-layer kinetics determines O(1) perturbations to the electric- and concentration fields in the surrounding electroneutral solution. Taking these effects into account, the expressions of the slip-flow coefficient and the effective surface boundary-conditions for the electric- and concentration fields are derived. For binary and symmetric electrolyte where only one ion species carries the current in the electroneutral domain, the far-field salt gradient as related to the electric field is determined. The electrodiffusiophoretic mobility is obtained for three particle geometries: sphere, cylinder and spheroid arbitrarily oriented with respect to the externally applied field. Strong departure from Smoluchowskian behavior is found. If co-ion is the current carrier, the mobility is independent of ζ, regardless of the body shape. Also, the hydrodynamic flow-field is irrotational. If counter-ion is the current carrier, the problem formulated in terms of a properly-defined scalar field (Ω), which embodies both the electric potential (Ψ) and the salt concentration, becomes formally identical to the one addressed in our previous work, concerning the small-ζ regime, with negligible salt gradients. Then, all the results obtained in that study are extended and applied even to the large-ζ regime considered here, provided the new expressions now derived for the surface boundary conditions and the slip-flow coefficient are employed and Ω is used in place of Ψ. The present results are discussed also in comparison with the classical studies of Dukhin et al and O'Brien et al concerning electrophoresis of highly charged particles with no salt gradient at infinity, and with recent studies of electrodiffusiophoresis, which, however, neglected the fields perturbations caused by Debye-layer kinetics. It is found that the effects addressed and incorporated

  15. Electroviscous effect on fluid drag in a microchannel with large zeta potential

    PubMed Central

    Jing, Dalei

    2015-01-01

    Summary The electroviscous effect has been widely studied to investigate the effect of surface charge-induced electric double layers (EDL) on the pressure-driven flow in a micro/nano channel. EDL has been reported to reduce the velocity of fluid flow and increase the fluid drag. Nevertheless, the study on the combined effect of EDL with large zeta potential up to several hundred millivolts and surface charge depenedent-slip on the micro/nano flow is still needed. In this paper, the nonlinear Poisson–Boltzmann equation for electrical potential and ion distribution in non-overlapping EDL is first analytically solved. Then, the modified Navier–Stokes equation for the flow considering the effect of surface charge on the electrical conductivity of the electrolyte and slip length is analytically solved. This analysis is used to study the effect of non-overlapping EDL with large zeta potential on the pressure-driven flow in a microchannel with no-slip and charge-dependent slip conditions. The results show that the EDL leads to an increase in the fluid drag, but that slip can reduce the fluid drag. When the zeta potential is large enough, the electroviscous effect disappears for flow in the microchannel under a no-slip condition. However, the retardation of EDL on the flow and the enhancement of slip on the flow counteract each other under a slip condition. The underlying mechanisms of the effect of EDL with large zeta potential on fluid drag are the high net ionic concentration near the channel wall and the fast decay of electrical potential in the EDL when the zeta potential is large enough. PMID:26734512

  16. Small differences in amylopectin fine structure may explain large functional differences of starch.

    PubMed

    Bertoft, Eric; Annor, George A; Shen, Xinyu; Rumpagaporn, Pinthip; Seetharaman, Koushik; Hamaker, Bruce R

    2016-04-20

    Four amylose-free waxy rice starches were found to give rise to gels with clearly different morphology after storage for seven days at 4°C. The thermal and rheological properties of these gels were also different. This was remarkable in light of the subtle differences in the molecular structure of the amylopectin in the samples. Addition of iodine to the amylopectin samples suggested that not only external chains, but also the internal chains of amylopectin, could form helical inclusion complexes. It is suggested that these internal helical segments participate in the retrogradation of amylopectin, thereby stabilising the gels through double helical structures with external chains of adjacent molecules. Albeit few in number, such interactions appear to have important influences on starch functional properties. PMID:26876834

  17. [Origin of the differences of superficial potentials in Rana esculenta].

    PubMed

    Fontas, B; Mambrini, J

    1977-07-18

    The spatial distributions of superficial D.C. potentials on the skin of Rana esculenta have been compared to those of the intensity of short-circuit current (S.C.C.) expressing the transcutaneous active transport of sodium ions. It has been observed that the sites of maximum D.C. potentials coincide with the localisations of maximum S.C.C. values. Moreover, superficial D.C. potentials and S.C.C. are similarly modified by the depression of metabolic activity due to lowered temperature or poisoning by dinitrophenol (DNP). It is thus proposed that the spatial distribution of the transcutaneous active transport system for sodium ions is the origin of the electric generator of superficial D.C. potentials. PMID:409557

  18. Antimicrobial potentials of different solvent extracted samples from Physalis ixocarpa.

    PubMed

    Khan, Wajid; Bakht, Jehan; Shafi, Mohammad

    2016-03-01

    The present study investigates the antimicrobial activities of different solvent extracted samples isolated from different parts of Physalis ixocarpa through disc diffusion assay using three different concentrations. Statistical analysis of the data revealed that different parts of the plant showed varying degree of inhibition against different bacteria at different concentrations. Different solvent extracted samples from the calyx showed inhibitory activity against most of the bacteria under study. Extracts from leaf and fruit samples showed activity against S. aureus and K. pneumoniae and extracts from the stem tissues were effective to control the growth of E. coli and K. pneumoniae. Crude methanolic extract from the stem and n-butanol extracted samples from fruit exhibited strong inhibitory activity against Klebsiella pneumoniae at highest concentrations. Antifungal activity was observed only in crude methanol extract from the leaf against Rhizopus stolinifer, Aspergillus niger and Penicillium chrysogenum. PMID:27087074

  19. PERSPECTIVES ON LARGE-SCALE NATURAL RESOURCES SURVEYS WHEN CAUSE-EFFECT IS A POTENTIAL ISSUE

    EPA Science Inventory

    Our objective is to present a perspective on large-scale natural resource monitoring when cause-effect is a potential issue. We believe that the approach of designing a survey to meet traditional commodity production and resource state descriptive objectives is too restrictive an...

  20. Assessment of Sugarcane Yield Potential across Large Numbers of Genotypes Using Canopy Reflectance Measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canopy reflectance indices have been used to monitor plant growth and estimate yields in many field crops. Little is known if canopy reflectance of sugarcane (a complex hybrid of Saccharum spp.) can be used to estimate growth and yield potential across large numbers of genotypes (clones) in the earl...

  1. Bose-Einstein condensation in large time-averaged optical ring potentials

    NASA Astrophysics Data System (ADS)

    Bell, Thomas A.; Glidden, Jake A. P.; Humbert, Leif; Bromley, Michael W. J.; Haine, Simon A.; Davis, Matthew J.; Neely, Tyler W.; Baker, Mark A.; Rubinsztein-Dunlop, Halina

    2016-03-01

    Interferometric measurements with matter waves are established techniques for sensitive gravimetry, rotation sensing, and measurement of surface interactions, but compact interferometers will require techniques based on trapped geometries. In a step towards the realisation of matter wave interferometers in toroidal geometries, we produce a large, smooth ring trap for Bose-Einstein condensates using rapidly scanned time-averaged dipole potentials. The trap potential is smoothed by using the atom distribution as input to an optical intensity correction algorithm. Smooth rings with a diameter up to 300 μm are demonstrated. We experimentally observe and simulate the dispersion of condensed atoms in the resulting potential, with good agreement serving as an indication of trap smoothness. Under time of flight expansion we observe low energy excitations in the ring, which serves to constrain the lower frequency limit of the scanned potential technique. The resulting ring potential will have applications as a waveguide for atom interferometry and studies of superfluidity.

  2. Near homogeneous variation of potentials in large systems and the electronic structure of molecular quantum dots.

    PubMed

    Luo, Ji; Yang, Zhong Qin; Xue, Zeng Quan; Liu, Wei Min; Wu, Jin Lei

    2006-09-01

    It is shown from Kohn-Sham (KS) density-functional theory that in a large molecular system, the Coulomb potential, molecular electrostatic potential, and KS effective potential may exhibit an approximately homogeneous variation in space, in response to a small change of the electron number. The homogeneous variation of potentials underlies the constant interaction (CI) model of quantum dots (QDs) and is related to the delocalization and invariance of KS orbitals, the identical shift of KS levels, and a natural definition of the QD capacitance. Calculation results of a fullerene C60 and a single-walled carbon nanotube are presented. Although the homogeneity of the potential variation is not perfect, it seems to lead to fairly good approximation of the CI model to the addition energy spectra of these systems. PMID:16965100

  3. Near homogeneous variation of potentials in large systems and the electronic structure of molecular quantum dots

    NASA Astrophysics Data System (ADS)

    Luo, Ji; Yang, Zhong Qin; Xue, Zeng Quan; Liu, Wei Min; Wu, Jin Lei

    2006-09-01

    It is shown from Kohn-Sham (KS) density-functional theory that in a large molecular system, the Coulomb potential, molecular electrostatic potential, and KS effective potential may exhibit an approximately homogeneous variation in space, in response to a small change of the electron number. The homogeneous variation of potentials underlies the constant interaction (CI) model of quantum dots (QDs) and is related to the delocalization and invariance of KS orbitals, the identical shift of KS levels, and a natural definition of the QD capacitance. Calculation results of a fullerene C60 and a single-walled carbon nanotube are presented. Although the homogeneity of the potential variation is not perfect, it seems to lead to fairly good approximation of the CI model to the addition energy spectra of these systems.

  4. Large Autosomal Copy-Number Differences within Unselected Monozygotic Twin Pairs are Rare.

    PubMed

    McRae, Allan F; Visscher, Peter M; Montgomery, Grant W; Martin, Nicholas G

    2015-02-01

    Monozygotic (MZ) twins form an important system for the study of biological plasticity in humans. While MZ twins are generally considered to be genetically identical, a number of studies have emerged that have demonstrated copy-number differences within a twin pair, particularly in those discordant for disease. The rate of autosomal copy-number variation (CNV) discordance within MZ twin pairs was investigated using a population sample of 376 twin pairs genotyped on Illumina Human610-Quad arrays. After CNV calling using both QuantiSNP and PennCNV followed by manual annotation, only a single CNV difference was observed within the MZ twin pairs, being a 130 KB duplication of chromosome 5. Five other potential discordant CNV were called by the software, but excluded based on manual annotation of the regions. It is concluded that large CNV discordance is rare within MZ twin pairs, indicating that any CNV difference found within phenotypically discordant MZ twin pairs has a high probability of containing the causal gene(s) involved. PMID:25578400

  5. Potential climatic impacts and reliability of very large-scale wind farms

    NASA Astrophysics Data System (ADS)

    Wang, C.; Prinn, R. G.

    2009-09-01

    Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has fueled legitimate interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1°C over land installations. In contrast, surface cooling exceeding 1°C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure reliability, including

  6. Potential climatic impacts and reliability of very large-scale wind farms

    NASA Astrophysics Data System (ADS)

    Wang, C.; Prinn, R. G.

    2010-02-01

    Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has fueled substantial interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1 °C over land installations. In contrast, surface cooling exceeding 1 °C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure reliability

  7. Direct computation of general chemical energy differences: Application to ionization potentials, excitation, and bond energies

    SciTech Connect

    Beste, Ariana; Harrison, Robert J; Yanai, Takeshi

    2006-01-01

    Chemists are mainly interested in energy differences. In contrast, most quantum chemical methods yield the total energy which is a large number compared to the difference and has therefore to be computed to a higher relative precision than would be necessary for the difference alone. Hence, it is desirable to compute energy differences directly, thereby avoiding the precision problem. Whenever it is possible to find a parameter which transforms smoothly from an initial to a final state, the energy difference can be obtained by integrating the energy derivative with respect to that parameter (c.f., thermodynamic integration or adiabatic connection methods). If the dependence on the parameter is predominantly linear, accurate results can be obtained by single-point integration. In density functional theory (DFT) and Hartree-Fock, we applied the formalism to ionization potentials, excitation energies, and chemical bond breaking. Example calculations for ionization potentials and excitation energies showed that accurate results could be obtained with a linear estimate. For breaking bonds, we introduce a non-geometrical parameter which gradually turns the interaction between two fragments of a molecule on. The interaction changes the potentials used to determine the orbitals as well as constraining the orbitals to be orthogonal.

  8. Direct computation of general chemical energy differences: Application to ionization potentials, excitation, and bond energies

    NASA Astrophysics Data System (ADS)

    Beste, A.; Harrison, R. J.; Yanai, T.

    2006-08-01

    Chemists are mainly interested in energy differences. In contrast, most quantum chemical methods yield the total energy which is a large number compared to the difference and has therefore to be computed to a higher relative precision than would be necessary for the difference alone. Hence, it is desirable to compute energy differences directly, thereby avoiding the precision problem. Whenever it is possible to find a parameter which transforms smoothly from an initial to a final state, the energy difference can be obtained by integrating the energy derivative with respect to that parameter (cf. thermodynamic integration or adiabatic connection methods). If the dependence on the parameter is predominantly linear, accurate results can be obtained by single-point integration. In density functional theory and Hartree-Fock, we applied the formalism to ionization potentials, excitation energies, and chemical bond breaking. Example calculations for ionization potentials and excitation energies showed that accurate results could be obtained with a linear estimate. For breaking bonds, we introduce a nongeometrical parameter which gradually turns the interaction between two fragments of a molecule on. The interaction changes the potentials used to determine the orbitals as well as the constraint on the orbitals to be orthogonal.

  9. Differences in the Glucuronidation of Resveratrol and Pterostilbene: Altered Enzyme Specificity and Potential Gender Differences

    PubMed Central

    Dellinger, Ryan W.; Gomez Garcia, Angela M.; Meyskens, Frank L.

    2015-01-01

    Summary Resveratrol, a natural polyphenol found in grapes, berries and other plants, has been proposed as an ideal chemopreventative agent due to its plethora of health promoting activities. However, despite its lofty promise as a cancer prevention agent its success in human clinical trials has been limited due to its poor bioavailability. Thus, interest in other natural polyphenols is intensifying including the naturally occurring dimethylated analog of resveratrol, pterostilbene. The UDP-glucuronosyltransferase (UGT) family of enzymes plays a vital role in the metabolism of both resveratrol and pterostilbene. The current study sought to elucidate the UGT family members responsible for the metabolism of pterostilbene and to examine gender differences in the glucuronidation of resveratrol and pterostilbene. We demonstrate that UGT1A1 and UGT1A3 are mainly responsible for pterostilbene glucuronidation although UGT1A8, UGT1A9 and UGT1A10 also had detectable activity. Intriguingly, UGT1A1 exhibits the highest activity against both resveratrol and pterostilbene despite altered hydroxyl group specificity. Using pooled human liver microsomes, enzyme kinetics were determined for pterostilbene and resveratrol glucuronides. In all cases females were more efficient than males, indicating potential gender differences in stilbene metabolism. Importantly, the glucuronidation of pterostilbene is much less efficient than that of resveratrol, indicating that pterostilbene will have dramatically decreased metabolism in humans. PMID:23965644

  10. Evaluating Potential for Large Releases from CO2 StorageReservoirs: Analogs, Scenarios, and Modeling Needs

    SciTech Connect

    Birkholzer, Jens; Pruess, Karsten; Lewicki, Jennifer; Tsang,Chin-Fu; Karimjee, Anhar

    2005-09-19

    While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhouse gases underground, the potential exists for CO{sub 2} to escape from the target reservoir, migrate upward along permeable pathways, and discharge at the land surface. Such discharge is not necessarily a serious concern, as CO{sub 2} is a naturally abundant and relatively benign gas in low concentrations. However, there is a potential risk to health, safety and environment (HSE) in the event that large localized fluxes of CO{sub 2} were to occur at the land surface, especially where CO{sub 2} could accumulate. In this paper, we develop possible scenarios for large CO{sub 2} fluxes based on the analysis of natural analogues, where large releases of gas have been observed. We are particularly interested in scenarios which could generate sudden, possibly self-enhancing, or even eruptive release events. The probability for such events may be low, but the circumstances under which they might occur and potential consequences need to be evaluated in order to design appropriate site selection and risk management strategies. Numerical modeling of hypothetical test cases is needed to determine critical conditions for such events, to evaluate whether such conditions may be possible at designated storage sites, and, if applicable, to evaluate the potential HSE impacts of such events and design appropriate mitigation strategies.

  11. Altered ion channel conductance and ionic selectivity induced by large imposed membrane potential pulse.

    PubMed Central

    Chen, W; Lee, R C

    1994-01-01

    The effects of large magnitude transmembrane potential pulses on voltage-gated Na and K channel behavior in frog skeletal muscle membrane were studied using a modified double vaseline-gap voltage clamp. The effects of electroconformational damage to ionic channels were separated from damage to lipid bilayer (electroporation). A 4 ms transmembrane potential pulse of -600 mV resulted in a reduction of both Na and K channel conductivities. The supraphysiologic pulses also reduced ionic selectivity of the K channels against Na+ ions, resulting in a depolarization of the membrane resting potential. However, TTX and TEA binding effects were unaltered. The kinetics of spontaneous reversal of the electroconformational damage of channel proteins was found to be dependent on the magnitude of imposed membrane potential pulse. These results suggest that muscle and nerve dysfunction after electrical shock may be in part caused by electroconformational damage to voltage-gated ion channels. PMID:7948676

  12. Potential use of a large-screen display for interpreting radiographic images

    NASA Astrophysics Data System (ADS)

    Krupinski, Elizabeth; Roehrig, Hans; Berger, William; Dalal, Sandeep; Stanton, Douglas

    2006-03-01

    Radiology has readily made the transition to the digital reading room. One commodity left behind when moving to digital displays however is display real estate. Even with multiple monitors radiologists cannot display numerous images as they did on a film alternator. We evaluated a large-screen rear-projection display (Philips Electronics) for potential use in radiology. Resolution was 1920 x 1080 with a 44-inch diagonal size and it was a color display. For comparison we used the IBM 9 Mpixel color display (22-inch diagonal) set to a comparable resolution and maximum luminance. Diagnostic accuracy with a series of bone images with subtle fractures and six observers was comparable (F = 0.3170, p = 0.5743) to traditional computer monitor. Viewing time, however, was significantly shorter (t = 6.723, p < 0.0001) with the large display for both normal and fracture images. On average, readers sat significantly closer (t = 5.578, p = 0.0026) to the small display than the large display. Four of the 6 radiologists preferred the smaller display, judging it to yield a sharper image. Half of the readers thought the black level was better with the large display and half with the small display. Most of the radiologists thought the large-screen display has potential for use in conferencing situations or those in which multiple viewers need to see images simultaneously.

  13. Hydrogen mixing and deflagration/detonation potential in a large, dry containment

    SciTech Connect

    Plys, M.G.; Elicson, G.T.; Cirauqui, C.; Otero, M.

    1996-12-31

    Severe accident analyses with MAAP4 may be supplemented by separate phenomena evaluations to determine the potential for deflagrations and detonations in a containment. Key phenomena evaluations are described here, and MAAP4 results are checked for consistency of the MAAP models for the case of a large, dry pressurized water reactor containment. For specific accident scenarios at Vandellos-II, we conclude that primary system heat losses induce significant containment mixing, rendering the potential for deflagration-to-detonation transition (DDT) highly unlikely to impossible and also signifying that hydrogen monitoring equipment should measure representative gas concentrations for application of severe accident management guidelines.

  14. Large endolymphatic potentials from low-frequency and infrasonic tones in the guinea pig.

    PubMed

    Salt, Alec N; Lichtenhan, Jeffery T; Gill, Ruth M; Hartsock, Jared J

    2013-03-01

    Responses of the ear to low-frequency and infrasonic sounds have not been extensively studied. Understanding how the ear responds to low frequencies is increasingly important as environmental infrasounds are becoming more pervasive from sources such as wind turbines. This study shows endolymphatic potentials in the third cochlear turn from acoustic infrasound (5 Hz) are larger than from tones in the audible range (e.g., 50 and 500 Hz), in some cases with peak-to-peak amplitude greater than 20 mV. These large potentials were suppressed by higher-frequency tones and were rapidly abolished by perilymphatic injection of KCl at the cochlear apex, demonstrating their third-turn origins. Endolymphatic iso-potentials from 5 to 500 Hz were enhanced relative to perilymphatic potentials as frequency was lowered. Probe and infrasonic bias tones were used to study the origin of the enhanced potentials. Potentials were best explained as a saturating response summed with a sinusoidal voltage (Vo), that was phase delayed by an average of 60° relative to the biasing effects of the infrasound. Vo is thought to arise indirectly from hair cell activity, such as from strial potential changes caused by sustained current changes through the hair cells in each half cycle of the infrasound. PMID:23464026

  15. Sagdeev potential approach for large amplitude compressional Alfvenic double layers in viscous plasmas

    SciTech Connect

    Panwar, Anuraj; Rizvi, H.; Ryu, C. M.

    2013-11-15

    Sagdeev’s technique is used to study the large amplitude compressional Alfvenic double layers in a magnetohydrodynamic plasma taking into account the small plasma β and small values of kinematic viscosity. Dispersive effect raised by non-ideal electron inertia currents perpendicular to the ambient magnetic field. The range of allowed values of the soliton speed, M (Mach number), plasma β (ratio of the plasma thermal pressure to the pressure in the confining magnetic field), and viscosity coefficient, wherein double layer may exist, are determined. In the absence of collisions, viscous dissipation modifies the Sagdeev potential and results in large amplitude compressional Alfvenic double layers. The depth of Sagdeev potential increases with the increasing Mach number and plasma β, however, decreases with the increasing viscosity. The double layer structure increases with the increasing plasma β, but decreases with increasing viscous dissipation μ(tilde sign)

  16. The Potential of Time Series Based Earth Observation for the Monitoring of Large River Deltas

    NASA Astrophysics Data System (ADS)

    Kuenzer, C.; Leinenkugel, P.; Huth, J.; Ottinger, M.; Renaud, F.; Foufoula-Georgiou, E.; Vo Khac, T.; Trinh Thi, L.; Dech, S.; Koch, P.; Le Tissier, M.

    2015-12-01

    Although river deltas only contribute 5% to the overall land surface, nearly six hundred million people live in these complex social-ecological environments, which combine a variety of appealing locational advantages. In many countries deltas provide the major national contribution to agricultural and industrial production. At the same time these already very dynamic environments are exposed to a variety of threats, including the disturbance and replacement of valuable ecosystems, increasing water, soil, and air pollution, human induced land subsidence, sea level rise, as well upstream developments impacting water and sediment supplies. A constant monitoring of delta systems is thus of utmost relevance for understanding past and current land surface change and anticipating possible future developments. We present the potential of Earth Observation based analyses and derived novel information products that can play a key role in this context. Along with the current trend of opening up numerous satellite data archives go increasing capabilities to explore big data. Whereas in past decades remote sensing data were analysed based on the spectral-reflectance-defined 'finger print' of individual surfaces, we mainly exploit the 'temporal fingerprints' of our land surface in novel pathways of data analyses at differing spatial-, and temporally-dense scales. Following our results on an Earth Observation based characterization of large deltas globally, we present in depth results from the Mekong Delta in Vietnam, the Yellow River Delta in China, the Niger Delta in Nigeria, as well as additional deltas, focussing on the assessment of river delta flood and inundation dynamics, river delta coastline dynamics, delta morphology dynamics including the quantification of erosion and accretion processes, river delta land use change and trends, as well as the monitoring of compliance to environmental regulations.

  17. A large self-potential anomaly on Unzen volcano, Shimabra peninsula, Kyushu island, Japan

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Tanaka, Y.

    1995-02-01

    Self-potential (SP) observation was carried out in the summit area of Unzen, one of the active volcanoes in Kyushu island, Japan. We found a positive SP anomaly in the vicinity of the newly extruded lava dome. The potential difference across the anomaly exceeds 1000 mV per 500 m. Streaming potentials associated with subsurface hydrothermal convection seem to be the most reasonable mechanism for the positive anomaly. In association with the first emergence of the lava dome a sharp increase of SP was detected, which is considered to be a result of the growth of the hydro-thermal system.

  18. Tsunamigenic potential of different tsunamigenic regions in the Pacific

    NASA Astrophysics Data System (ADS)

    Gusiakov, V. K.

    2003-04-01

    The historical tsunami catalog collected within the HTDB/PAC (Historical Tsunami Database for the Pacific) project contains the most complete parametric tsunami data covering the Pacific. The collected data gives us a possibility to study the variability of the tsunami potential of submarine earthquakes over the main tsunamigenic areas in the Pacific. Depending on their intensity (on the Soloviev-Imamura scale) all the tsunamigenic events were divided into the three categories: damageable (I>1.5, Hav>3 m), perceptible (-0.5 <= I <= 1.5, 0.5 <= Hav <= 3m) and observable (I < -0.5, Hav < 0.5m), where Hav is an average run-up height at the nearest coast. For each region, the tsunami efficiency (TE) is calculated as a ratio between the number of tsunamis of tectonic, landslide and unknown origin and the total number of the coastal and the submarine earthquakes with magnitude Ms = 7.0 and depth h < 100 km. In the Pacific, the tsunami efficiency, calculated in the above manner, varies from 84% for the South America region to 36% for the New Zealand - Tonga region. The comparison of the variation of the TE ratio with the position of the main sedimentation zones in the Pacific (Lisitsyn, 1974) shows that the regions located within the equatorial humid zone (New Guinea - Solomon, Indonesia, Philippines) have the increased number of tsunamigenic events compared to the regions located in other zones. The circum-continental zonation in the sedimentation rate resulted in the highest TE ratio for the South America region where the tsunamigenic sources are located closest to land. The higher sedimentation rate results in a higher potential for submarine slumping that considerably increases the efficiency of the tsunami generation mechanism. The earthquakes in the marginal seas (the Japan Sea, the Okhotsk Sea, the Bering Sea) have a higher tsunami efficiency as compared to the earthquakes in the Pacific ocean. For Hawaii, the TE ratio exceeds 100%, which shows that some events

  19. Differences in angiogenic potential of classically vs alternatively activated macrophages.

    PubMed

    Kodelja, V; Müller, C; Tenorio, S; Schebesch, C; Orfanos, C E; Goerdt, S

    1997-11-01

    Macrophages (M phi) are important for angiogenesis during inflammation, wound repair, and tumor growth. However, well-characterized M phi subsets such as IFN-gamma-induced, classically activated (ca) M phi or IL-4/glucocorticoid-induced, alternatively activated (aa) M phi have not been thoroughly examined for a positive or negative association with angiogenesis. While caM phi populate early inflammatory reactions and high-turnover granulomas, aaM phi occur in healing wounds and chronic inflammation. In contrast to caM phi-dominated lesions, aaM phi-rich lesions are highly vascularized. In order to determine their angiogenic potential in vitro, these M phi subsets as well as unstimulated control macrophages (coM phi) were analyzed by RT-PCR for mRNA expression of 10 angiogenic factors after 3 and 6 days of culture. Early during activation, caM phi and coM phi expressed equal levels of 8 of 10 angiogenic factors (PDGF-A, MK, TNF-alpha, TGF-beta 1, PDGF-B, HGF, TGF-alpha, IGF-1), while aaM phi showed expression of only 4 of these factors (TGF-beta 1, PDGF-B, HGF, GF-1). After maturation, TGF-alpha and IGF-1 showed a shift in mRNA expression from caM phi to aaM phi resulting in a considerably enhanced expression of these factors in day-6 aaM phi as compared to day-6 caM phi and coM phi while PDGF-A, MK, and TNF-alpha remained suppressed in day 6 aaM phi. In all M phi subsets including controls, mRNA expression of aFGF and bFGF was minimal or absent while TGFG-beta 1, HGF, and ODGF-B were constitutively expressed. In order to functionally integrate angiogenic factor mRNA expression profiles, mitogenic activity of M phi subsets towards microvascular endothelium was assessed by cocultivation. Coculture experiments revealed that endothelial proliferation induced by aaM phi was 3.0-3.5x higher than induced by caM phi. In conclusion, mature aaM phi are well equipped to play an important role in protracted M phi-associated angiogenic processes. Presumably due to expression of

  20. Large 0/12 GMT Differences of US Vaisala RS80 Observations

    NASA Technical Reports Server (NTRS)

    Atlas, Robert (Technical Monitor)

    2002-01-01

    Large differences been observations taken at 0 and 12 GMT have been revealed during routine monitoring of observations at the Data Assimilation Office (DAO) at NASA's Goddard Space Flight Center (GSFC). As a result, an investigation has been conducted to confirm the large differences and isolate its source. The data clearly shows that 0/12 GMT differences are largely artificial especially over the central US and that the differences largely originate in the post processing software at the observing stations. In particular, the release time of the rawinsonde balloon may be misspecified to be the synoptic time which would lead to the miscalculation of the bias correction that accounts for solar radiation effects on the thermistor.

  1. Individual Differences in Fear Potentiated Startle in Behaviorally Inhibited Children

    PubMed Central

    Barker, Tyson V.; Reeb-Sutherland, Bethany; Fox, Nathan A.

    2014-01-01

    Behavioral inhibition (BI) is a temperament characterized during early childhood by increased fearfulness to novelty, social reticence to unfamiliar peers, and heightened risk for the development of anxiety. Heightened startle responses to safety cues have been found among behaviorally inhibited adolescents who have an anxiety disorder suggesting that this measure may serve as a biomarker for the development of anxiety amongst this risk population. However, it is unknown if these aberrant startle patterns emerge prior to the manifestation of anxiety in this temperament group. The current study examined potentiated startle in 7-year-old children characterized with BI early in life. High behaviorally inhibited children displayed increased startle magnitude to safety cues, particularly during the first half of the task, and faster startle responses compared to low behaviorally inhibited children. These findings suggest that aberrant startle responses are apparent in behaviorally inhibited children during early childhood prior to the onset of a disorder and may serve as a possible endophenotype for the development of anxiety PMID:23341151

  2. On hemispheric differences in evoked potentials to speech stimuli

    NASA Technical Reports Server (NTRS)

    Galambos, R.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.; Benson, P.

    1975-01-01

    Subjects were asked to count the number of times a 'target' sound occurred in lists of speech sounds (pa or ba) or pure tones (250 or 600 c/sec) in which one of the sounds (the 'frequent') appeared about four times as often as the target. The response to both targets and frequents were separately averaged from electrodes at vertex at symmetrical left and right parietal locations. The expected sequence of deflections, including P3 waves with about 350 msec latency, was found in the responses to target stimuli. Very little difference was found between the right and left hemispheric responses to speech or pure tones, either frequent or target.

  3. Investigating the Potential for Large-Scale Carbon Dioxide Sequestration in Shale Gas Formations

    NASA Astrophysics Data System (ADS)

    Edwards, R.; Celia, M. A.; Kanno, C.; Bandilla, K.; Doster, F.

    2014-12-01

    Recent studies [Godec et al., Int. J. Coal. Geol., 2013; Liu et al., IJGGC, 2013; Tao and Clarens, ES&T, 2013] have suggested the possibility of geological CO2 sequestration in depleted shale gas formations, motivated by large storage capacity estimates in these formations. The kinetics and practicality of injecting large amounts of CO2 into shale gas wells at the appropriate scale remain as open questions. To further investigate the feasibility of CO2 sequestration, models of gas flow and storage in a horizontal shale gas well were developed based on observed behavior of gas production data and the associated models that are consistent with those observations [Patzek et al., PNAS, 2013]. Both analytical and numerical models were used to investigate the well-scale kinetics of CO2 injection into a typical shale gas well. It was found that relatively low rates could be injected into individual wells compared with CO2 emissions from large industrial sources, and that injection rates would rapidly decline with time. Based on typical well parameters, 170 wells would be required to inject the emissions from one large coal-fired power plant over a 15 year period. Significant practical and logistical challenges to industrial-scale CO2 sequestration in depleted shale gas formations arise due to the relatively low injection rates, low storage capacity of individual wells and large numbers of wells required. These challenges include the difficulty of managing the required large, ever-changing networks of injection wells, potentially prohibitive energy requirements, and leakage concerns in hydraulically fractured wells. The combination of these factors, and the fact that they are all likely less of an issue for other potential geological sequestration targets such as deep saline aquifers, mean that targets in conventional formations are more likely to be suitable for industrial-scale CO2 sequestration.

  4. Differences in insulin biosynthesis pathway between small and large islets do not correspond to insulin secretion

    PubMed Central

    Huang, Han-Hung; Stehno-Bittel, Lisa

    2015-01-01

    In a variety of mammalian species, small islets secrete more insulin per volume than large islets. This difference may be due to diffusional limitations of large islets, or inherent differences in the insulin production pathways. The purpose of this study was to identify possible differences in the early phase of glucose-stimulated insulin biosynthesis between large and small islets. Isolated small and large rat islets were challenged with 30 minutes of high glucose. The expression of insulin gene transcription factors (MafA, NeuroD/ Beta2, and PDX-1), preproinsulin mRNA, proinsulin and insulin were compared between large and small islets. Under basal (low glucose) conditions, MafA and NeuroD had higher mRNA levels and greater protein amounts in large islets compared to small when normalized to GAPDH levels. 30 minutes of high glucose stimulation failed to alter the mRNA or subsequent protein levels of either gene. However, 30 minutes of high glucose suppressed activated PDX-1 protein levels in both small and large islets. High glucose stimulation did not statistically alter the preproinsulin mRNA (insulin 1 and insulin 2) levels. At the translational level, high glucose increased the proinsulin levels, and large islets showed a higher proinsulin content per cell than small islets. Insulin content per cell was not significantly different between small and large islets under basal or high glucose levels. The results fail to explain the higher level of insulin secretion noted in small versus large islets and may suggest that possible differences lie downstream in the secretory pathway rather than insulin biosynthesis. PMID:26752360

  5. The potential for agricultural land use change to reduce flood risk in a large watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of agricultural land management practices on surface runoff are evident at local scales, but evidence for watershed-scale impacts is limited. In this study, we used the Soil and Water Assessment Tool model to assess changes in downstream flood risks under different land uses for the large, ...

  6. 77 FR 11111 - Assessment of Potential Large-Scale Mining on the Bristol Bay Watershed of Alaska: Nomination of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... AGENCY Assessment of Potential Large-Scale Mining on the Bristol Bay Watershed of Alaska: Nomination of... impacts associated with potential large-scale mining development in the Nushagak and Kvichak watersheds of... how large-scale mining activities might affect water quality and habitat. EPA will focus primarily...

  7. Regional modeling of large wildfires under current and potential future climates in Colorado and Wyoming, USA

    USGS Publications Warehouse

    West, Amanda; Kumar, Sunil; Jarnevich, Catherine S.

    2016-01-01

    Regional analysis of large wildfire potential given climate change scenarios is crucial to understanding areas most at risk in the future, yet wildfire models are not often developed and tested at this spatial scale. We fit three historical climate suitability models for large wildfires (i.e. ≥ 400 ha) in Colorado andWyoming using topography and decadal climate averages corresponding to wildfire occurrence at the same temporal scale. The historical models classified points of known large wildfire occurrence with high accuracies. Using a novel approach in wildfire modeling, we applied the historical models to independent climate and wildfire datasets, and the resulting sensitivities were 0.75, 0.81, and 0.83 for Maxent, Generalized Linear, and Multivariate Adaptive Regression Splines, respectively. We projected the historic models into future climate space using data from 15 global circulation models and two representative concentration pathway scenarios. Maps from these geospatial analyses can be used to evaluate the changing spatial distribution of climate suitability of large wildfires in these states. April relative humidity was the most important covariate in all models, providing insight to the climate space of large wildfires in this region. These methods incorporate monthly and seasonal climate averages at a spatial resolution relevant to land management (i.e. 1 km2) and provide a tool that can be modified for other regions of North America, or adapted for other parts of the world.

  8. Acrylamide formation in different foods and potential strategies for reduction.

    PubMed

    Stadler, Richard H

    2005-01-01

    This paper summarizes the progress made to date on acrylamide research pertaining to analytical methods, mechanisms of formation, and mitigation research in the major food categories. Initial difficulties with the establishment of reliable analytical methods have today in most cases been overcome, but challenges still remain in terms of the needs to develop simple and rapid test methods. Several researchers have identified that the main pathway of formation of acrylamide in foods is linked to the Maillard reaction and in particular the amino acid asparagine. Decarboxylation of the resulting Schiff base is a key step, and the reaction product may either furnish acrylamide directly or via 3-aminopropionamide. An alternative proposal is that the corresponding decarboxylated Amadori compound may release acrylamide by a beta-elimination reaction. Many experimental trials have been conducted in different foods, and a number of possible measures identified to relatively lower the amounts of acrylamide in food. The validity of laboratory trials must, however, be assessed under actual food processing conditions. Some progress in relatively lowering acrylamide in certain food categories has been achieved, but can at this stage be considered marginal. However, any options that are chosen to reduce acrylamide must be technologically feasible and also not negatively impact the quality and safety of the final product. PMID:16438297

  9. Development of a carbonate platform with potential for large discoveries - an example from Vietnam

    SciTech Connect

    Mayall, M.; Bent, A.; Dale, B. )

    1996-01-01

    In offshore central and southern Vietnam a number of carbonate accumulations can be recognized. Platform carbonates form basin-wide units of carbonate characterized by strong, continuous parallel seismic reflectors. Facies are dominated by bioclastic wackestones with poor-moderate reservoir quality. On the more isolated highs, large buildups developed. These are typically 5-10 km across and 300 m thick. They unconformably overlie the platform carbonate facies which are extensively karstified. In places these are pinnacles, typically 2-5 km across, 300 m+ thick with chaotic or mounded internal seismic facies. The large carbonate buildups are characterized by steep sided slopes with talus cones, reef-margin rims usually developed around only part of the buildup, and a prominent back-stepping geometry. Buildup interior facies form the main potential reservoirs They are dominated by fine to coarse grained coralgal packstones. Fine grained carbonates are associated with deeper water events and multiple karst surfaces can also be identified. Reservoir quality is excellent, largely controlled by extensive dissolution and dolomitization believed to be related to the exposure events. Gas has been found in a number of reservoirs. Heterogeneities can be recognized which could potentially effect production. These include the extensive finer grained facies, cementation or open fissures associated with the karst surfaces, a more cemented reef rim, shallowing upwards facies cycles and faults.

  10. Development of a carbonate platform with potential for large discoveries - an example from Vietnam

    SciTech Connect

    Mayall, M.; Bent, A.; Dale, B.

    1996-12-31

    In offshore central and southern Vietnam a number of carbonate accumulations can be recognized. Platform carbonates form basin-wide units of carbonate characterized by strong, continuous parallel seismic reflectors. Facies are dominated by bioclastic wackestones with poor-moderate reservoir quality. On the more isolated highs, large buildups developed. These are typically 5-10 km across and 300 m thick. They unconformably overlie the platform carbonate facies which are extensively karstified. In places these are pinnacles, typically 2-5 km across, 300 m+ thick with chaotic or mounded internal seismic facies. The large carbonate buildups are characterized by steep sided slopes with talus cones, reef-margin rims usually developed around only part of the buildup, and a prominent back-stepping geometry. Buildup interior facies form the main potential reservoirs They are dominated by fine to coarse grained coralgal packstones. Fine grained carbonates are associated with deeper water events and multiple karst surfaces can also be identified. Reservoir quality is excellent, largely controlled by extensive dissolution and dolomitization believed to be related to the exposure events. Gas has been found in a number of reservoirs. Heterogeneities can be recognized which could potentially effect production. These include the extensive finer grained facies, cementation or open fissures associated with the karst surfaces, a more cemented reef rim, shallowing upwards facies cycles and faults.

  11. Improving High School Students' Understanding of Potential Difference in Simple Electric Circuits

    ERIC Educational Resources Information Center

    Liegeois, Laurent; Chasseigne, G'erard; Papin, Sophie; Mullet, Etienne

    2003-01-01

    This paper reports two studies into the understanding of the concept of potential difference in the current-potential difference-resistance context among 8th-12th graders (Study 1), and the efficiency of a learning device derived from Social Judgment Theory (Study 2). These two studies showed that: (a) when asked to infer potential difference from…

  12. Gender Differences in Large-Scale Math Assessments: PISA Trend 2000 and 2003

    ERIC Educational Resources Information Center

    Liu, Ou Lydia; Wilson, Mark

    2009-01-01

    Many efforts have been made to determine and explain differential gender performance on large-scale mathematics assessments. A well-agreed-on conclusion is that gender differences are contextualized and vary across math domains. This study investigated the pattern of gender differences by item domain (e.g., Space and Shape, Quantity) and item type…

  13. Large-rock avalanche deposits, eastern Basin and Range, Utah: Emplacement, diagenesis, and economic potential

    SciTech Connect

    Morris, T.H.; Hebertson, G.F.

    1996-07-01

    Large-rock avalanche deposits are a common component of the basin fill within the extensional tectonic terrain of the Basin and Range; these deposits recently have been interpreted to host oil and gas within the Railroad Valley area of eastern Nevada. Large blocks of brecciated bedrock are a primary component of these avalanche deposits and are potentially excellent oil and gas reservoirs. Our work provides further insight into the emplacement and economic potential of these deposits. Exposed large-rock avalanche deposits of the Miocene Oak City Formation on the western margin of the Canyon Range, Utah, contain coherent breccia blocks up to 3.5 km long, 1 km wide, and 200 m thick. These deposits were derived from the near-vertical dipping bed rock of the adjacent Canyon Range and now are exposed as much as 5.5 km from the range front within the Sevier Desert basin. Emplacement was relatively rapid, as indicated by three well-developed breccia facies within the carbonate breccia blocks. Stratigraphically, from the base the facies include (1) matrix-rich breccia, (2) jigsaw breccia, and (3) crackle breccia. The deposits were cut and segmented by a series of syn-depositional normal faults that developed during late Miocene and post-Miocene extension. Primary porosity was reduced by cement soon after burial. Cathodoluminescence cement patterns indicate that initially the basinward breccia blocks were more deeply buried relative to the water table than the breccia blocks proximal to the Canyon Range. After initial cementation, the basinward blocks were uplifted relative to the water table. Secondary porosity approaches 8% in the carbonate blocks and is greater than 14% within the jigsaw breccia. The size and porosity of these breccia blocks indicate their potential as reservoir targets.

  14. Latency correction of event-related potentials between different experimental protocols

    NASA Astrophysics Data System (ADS)

    Iturrate, I.; Chavarriaga, R.; Montesano, L.; Minguez, J.; Millán, JdR

    2014-06-01

    Objective. A fundamental issue in EEG event-related potentials (ERPs) studies is the amount of data required to have an accurate ERP model. This also impacts the time required to train a classifier for a brain-computer interface (BCI). This issue is mainly due to the poor signal-to-noise ratio and the large fluctuations of the EEG caused by several sources of variability. One of these sources is directly related to the experimental protocol or application designed, and may affect the amplitude or latency of ERPs. This usually prevents BCI classifiers from generalizing among different experimental protocols. In this paper, we analyze the effect of the amplitude and the latency variations among different experimental protocols based on the same type of ERP. Approach. We present a method to analyze and compensate for the latency variations in BCI applications. The algorithm has been tested on two widely used ERPs (P300 and observation error potentials), in three experimental protocols in each case. We report the ERP analysis and single-trial classification. Main results. The results obtained show that the designed experimental protocols significantly affect the latency of the recorded potentials but not the amplitudes. Significance. These results show how the use of latency-corrected data can be used to generalize the BCIs, reducing the calibration time when facing a new experimental protocol.

  15. Structural Architecture of the Western Transverse Ranges and Potential for Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Levy, Y.; Rockwell, T. K.; Driscoll, N. W.; Shaw, J. H.; Kent, G. M.; Ucarkus, G.

    2015-12-01

    Understanding the subsurface structure of the Western Transverse Ranges (WTR) is critical to assess the seismic potential of large thrust faults comprising this fold-and-thrust belt. Several models have been advanced over the years, building on new data and understandings of thrust belt architecture, but none of these efforts have incorporated the full range of data, including style and rates of late Quaternary deformation in conjunction with surface geology, sub-surface well data and offshore seismic data. In our models, we suggest that the nearly continuous backbone with continuous stratigraphy of the Santa Ynez Mountains is explained by a large anticlinorium over a deep structural ramp, and that the current thrust front is defined by the southward-vergent Pitas Point-Ventura fault. The Ventura Avenue anticline and trend is an actively deforming fault propagation fold over the partially blind Pitas Point-Ventura fault. Details of how this fault is resolved to the surface are not well constrained, but any deformation model must account for the several back-thrusts that ride in the hanging wall of the thrust sheet, as well as the localized subsidence in Carpenteria and offshore Santa Barbara. Our preliminary starting model is a modification of a recently published model that invokes ramp-flat structure, with a deep ramp under the Santa Ynez Mountains, a shallower "flat" with considerable complexity in the hanging wall and a frontal ramp comprising the San Cayetano and Pitas Point thrusts. With the inferred deep ramp under the Santa Ynez Range, this model implies that large earthquakes may extend the entire length of the anticlinorium from Point Conception to eastern Ventura Basin, suggesting that the potential for a large earthquake is significantly higher then previously assumed.

  16. Submm/FIR Astronomy in Antarctica: Potential for a large telescope facility

    NASA Astrophysics Data System (ADS)

    Minier, V.; Olmi, L.; Lagage, P.-O.; Spinoglio, L.; Durand, G. A.; Daddi, E.; Galilei, D.; Gallée, H.; Kramer, C.; Marrone, D.; Pantin, E.; Sabbatini, L.; Schneider, N.; Tothill, N. F. H.; Valenziano, L.; Veyssière, C.

    Preliminary site testing datasets suggest that Dome C in Antarctica is one of the best sites on Earth for astronomical observations in the 200 to 500-μm regime, i.e. for far-infrared (FIR) and submillimetre (submm) astronomy. We present an overview of potential science cases that could be addressed with a large telescope facility at Dome C. This paper also includes a presentation of the current knowledge about the site characterics in terms of atmospheric transmission, stability, sky noise and polar constraints on telescopes. Current and future site testing campaigns are finally described.

  17. Angular dependent potential for α-boron and large-scale molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Pokatashkin, P.; Kuksin, A.; Yanilkin, A.

    2015-06-01

    Both quantum mechanical and molecular-dynamics (MD) simulations of α-boron are done at this work. Angular dependent interatomic potential (ADP) for boron is obtained using force-matching technique. Fitting data are based on ab initio results within  -20..100 GPa pressure range and temperatures up to 2000 K. Characteristics of α-boron, obtained using ADP potential such as bond lengths at equilibrium condition, bulk modulus, pressure-volume relations, Gruneisen coefficient, thermal expansion coefficient are in good agreement with both ab initio data, obtained in this work and known experimental data. As an example of application, the propagation of shock waves through a single crystal of α-boron is also explored by large-scale MD simulations.

  18. Efficient parallelization of analytic bond-order potentials for large-scale atomistic simulations

    NASA Astrophysics Data System (ADS)

    Teijeiro, C.; Hammerschmidt, T.; Drautz, R.; Sutmann, G.

    2016-07-01

    Analytic bond-order potentials (BOPs) provide a way to compute atomistic properties with controllable accuracy. For large-scale computations of heterogeneous compounds at the atomistic level, both the computational efficiency and memory demand of BOP implementations have to be optimized. Since the evaluation of BOPs is a local operation within a finite environment, the parallelization concepts known from short-range interacting particle simulations can be applied to improve the performance of these simulations. In this work, several efficient parallelization methods for BOPs that use three-dimensional domain decomposition schemes are described. The schemes are implemented into the bond-order potential code BOPfox, and their performance is measured in a series of benchmarks. Systems of up to several millions of atoms are simulated on a high performance computing system, and parallel scaling is demonstrated for up to thousands of processors.

  19. Foraging and growth potential of juvenile Chinook Salmon after tidal restoration of a large river delta

    USGS Publications Warehouse

    David, Aaron T.; Ellings, Christopher; Woo, Isa; Simenstad, Charles A.; Takekawa, John Y.; Turner, Kelley L.; Smith, Ashley L.; Takekawa, Jean E.

    2014-01-01

    We evaluated whether restoring tidal flow to previously diked estuarine wetlands also restores foraging and growth opportunities for juvenile Chinook Salmon Oncorhynchus tshawytscha. Several studies have assessed the value of restored tidal wetlands for juvenile Pacific salmon Oncorhynchus spp., but few have used integrative measures of salmon performance, such as habitat-specific growth potential, to evaluate restoration. Our study took place in the Nisqually River delta, Washington, where recent dike removals restored tidal flow to 364 ha of marsh—the largest tidal marsh restoration project in the northwestern contiguous United States. We sampled fish assemblages, water temperatures, and juvenile Chinook Salmon diet composition and consumption rates in two restored and two reference tidal channels during a 3-year period after restoration; these data were used as inputs to a bioenergetics model to compare Chinook Salmon foraging performance and growth potential between the restored and reference channels. We found that foraging performance and growth potential of juvenile Chinook Salmon were similar between restored and reference tidal channels. However, Chinook Salmon densities were significantly lower in the restored channels than in the reference channels, and growth potential was more variable in the restored channels due to their more variable and warmer (2°C) water temperatures. These results indicate that some—but not all—ecosystem attributes that are important for juvenile Pacific salmon can recover rapidly after large-scale tidal marsh restoration.

  20. Chemical and structural indicators for large redox potentials in Fe-based positive electrode materials.

    PubMed

    Melot, Brent C; Scanlon, David O; Reynaud, Marine; Rousse, Gwenaëlle; Chotard, Jean-Noël; Henry, Marc; Tarascon, Jean-Marie

    2014-07-23

    Li-ion batteries have enabled a revolution in the way portable consumer-electronics are powered and will play an important role as large-scale electrochemical storage applications like electric vehicles and grid-storage are developed. The ability to identify and design promising new positive insertion electrodes will be vital in continuing to push Li-ion technology to its fullest potential. Utilizing a combination of computational tools and structural analysis, we report new indicators which will facilitate the recognition of phases with the desired redox potential. Most importantly of these, we find there is a strong correlation between the presence of Li ions sitting in close-proximity to the redox center of polyanionic phases and the open circuit voltage in Fe-based cathodes. This common structural feature suggests that the bonding associated with Li may have a secondary inductive effect which increases the ionic character of Fe bonds beyond what is typically expected based purely on arguments of electronegativity associated with the polyanionic group. This correlation is supported by ab initio calculations which show the Bader charge increases (reflecting an increased ionicity) in a nearly linear fashion with the experimental cell potentials. These features are demonstrated to be consistent across a wide variety of compositions and structures and should help to facilitate the design of new, high-potential, and environmentally sustainable insertion electrodes. PMID:24588538

  1. Numerical solution of differential-difference equations in large intervals using a Taylor collocation method

    NASA Astrophysics Data System (ADS)

    Tirani, M. Dadkhah; Sohrabi, F.; Almasieh, H.; Kajani, M. Tavassoli

    2015-10-01

    In this paper, a collocation method based on Taylor polynomials is developed for solving systems linear differential-difference equations with variable coefficients defined in large intervals. By using Taylor polynomials and their properties in obtaining operational matrices, the solution of the differential-difference equation system with given conditions is reduced to the solution of a system of linear algebraic equations. We first divide the large interval into M equal subintervals and then Taylor polynomials solutions are obtained in each interval, separately. Some numerical examples are given and results are compared with analytical solutions and other techniques in the literature to demonstrate the validity and applicability of the proposed method.

  2. Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential.

    PubMed

    Hafner, Polona; Gričar, Jožica; Skudnik, Mitja; Levanič, Tom

    2015-01-01

    We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW). For that purpose EW and LW widths and carbon isotope discrimination for the period 1970-2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August) climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon isotope

  3. Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential

    PubMed Central

    Hafner, Polona; Gričar, Jožica; Skudnik, Mitja; Levanič, Tom

    2015-01-01

    We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW). For that purpose EW and LW widths and carbon isotope discrimination for the period 1970–2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August) climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon

  4. Small duct primary sclerosing cholangitis without inflammatory bowel disease is genetically different from large duct disease

    PubMed Central

    Næss, Sigrid; Björnsson, Einar; Anmarkrud, Jarl A.; Al Mamari, Said; Juran, Brian D.; Lazaridis, Konstantinos N.; Chapman, Roger; Bergquist, Annika; Melum, Espen; Marsh, Steven G. E.; Schrumpf, Erik; Lie, Benedicte A.; Boberg, Kirsten Muri; Karlsen, Tom H.; Hov, Johannes R.

    2014-01-01

    Background & aims Small duct primary sclerosing cholangitis (PSC) is phenotypically a mild version of large duct PSC, but it is unknown whether these phenotypes share aetiology. We aimed to characterize their relationship by investigating genetic associations in the HLA complex, which represent the strongest genetic risk factors in large duct PSC. Methods Four classical HLA loci (HLA-A, HLA-B, HLA-C, HLA-DRB1) were genotyped in 87 small duct PSC patients, 485 large duct PSC patients and 1117 controls across three geographical regions. Results HLA-DRB1*13:01 (OR=2.0, 95% CI 1.2–3.4, P=0.01) and HLA-B*08 (OR=1.6, 95% CI 1.1–2.4, P=0.02) were significantly associated with small duct PSC compared with healthy controls. Based on the observed frequency of HLA-B*08 in small duct PSC, the strongest risk factor in large duct PSC, an estimated 32% (95% CI 4%–65%) of this population can be hypothesized to represent early stages or mild variants of large duct PSC. This subgroup may be constituted by small duct PSC patients with inflammatory bowel disease (IBD), which greatly resembled large duct PSC in its HLA association. In contrast, small duct PSC without IBD was only associated with HLA-DRB1*13:01(P=0.03) and was otherwise distinctly dissimilar from large duct PSC. Conclusions Small duct PSC with IBD resembles large duct PSC in its HLA association and may represent early stages or mild variants of large duct disease. Different HLA associations in small duct PSC without IBD could indicate that this subgroup is a different entity. HLA-DRB1*13:01 may represent a specific risk factor for inflammatory bile duct disease. PMID:24517468

  5. Potential large wood-related hazards at bridges: the Czarny Dunajec River (Poland)

    NASA Astrophysics Data System (ADS)

    Ruiz-Villanueva, Virginia; Wyżga, Bartłomiej; Mikuś, Paweł; Hajdukiewicz, Maciej; Stoffel, Markus

    2016-04-01

    Besides high water levels in the drainage network and important channel changes, the transport of large quantities of wood material must be considered an additional factor of flood hazard in forested areas. At critical sections such as bridges, the effect of the transport and deposition of large quantities of wood during floods is mainly a reduction of the cross-sectional area, triggering a quick succession of backwater effects with inundation of the adjacent valley floor, bed aggradation, channel avulsion and local scouring processes that ultimately may cause embankment/bridge collapse and bank erosion. Therefore, the aim of this work is to analyse potential hazards related to wood transport and deposition in the reach of the Czarny Dunajec (Tatra Mountains foreland, Polish Carpathians) where the river flows through the village of Długopole. Buildings in the village are located very close to the river and the bridge has a very narrow cross-section and is thus threatened by wood-related phenomena. The approach is based on the combination of numerical modelling and field observations. A numerical model which simulates the transport of large wood together with flow dynamics is applied and inlet and boundary conditions are designed based on field observations. We established several scenarios for flow conditions and the wood transport. Results provided data to compute bridge clogging probability under the designed scenarios and the potential impacts of the clogging on hydrodynamics, flooded area and effects on the bridge. This information will be very useful for flood risk assessment and management of the river. This work was supported by the Polish-Swiss FLORIST project (Flood risk on the northern foothills of the Tatra Mountains; PSPB no. 153/2010).

  6. Zero-current potentials in a large membrane channel: a simple theory accounts for complex behavior.

    PubMed Central

    Zambrowicz, E B; Colombini, M

    1993-01-01

    Flow of ions through large channels is complex because both cations and anions can penetrate and multiple ions can be in the channel at the same time. A modification of the fixed-charge membrane theory of Teorell was reported (Peng, S., E. Blachly-Dyson, M. Forte, and M. Colombini. 1992. Biophys. J. 62:123-135) in which the channel is divided into two compartments: a relatively charged cylindrical shell of solution adjacent to the wall of the pore and a relatively neutral central cylinder of solution. The zero-current (reversal) potential results in current flow in opposite directions in these two compartments. This description accounted rather well for the observed reversal potential changes following site-directed mutations. Here we report the results of systematic tests of this simple theory with the mitochondrial channel, VDAC (isolated from Neurospora crassa), reconstituted into planar phospholipid membranes. The variation of the observed reversal potential with transmembrane activity ratio, ionic strength, ion mobility ratio, and net charge on the wall of the pore are accounted for reasonably well. The Goldman-Hodgkin-Katz theory fails to account for the observations. PMID:7694668

  7. Isn't the space-charge potential in ceria-based solid electrolytes largely overestimated?

    PubMed

    Kim, Sangtae

    2016-07-20

    The effective ionic conductivity of polycrystalline solid electrolytes that conduct oxide ions or protons is known to be markedly below those of the corresponding single crystals due to substantial current obstruction across the grain boundary. Numerous studies have previously demonstrated that the ionic charge carriers deplete in the vicinity of the grain boundary to form a potential barrier at the grain boundary, which further impedes the current across the grain boundary. Hence an accurate estimation of the barrier height is essential to acquire a comprehensive and precise mechanistic picture of the ionic current in solid electrolytes. The values of the potential barrier height, i.e. equivalent to the equilibrium space-charge potential with the opposite sign, in prominent solid electrolytes such as ceria solid solutions are available in the literature and were determined exclusively from the ratio of the resistivity of the grain boundary to that of the crystal interior. Here I present the results clearly demonstrating that the resistivity ratio yields considerable overestimation of the barrier height even in relatively diluted solid solutions of ceria. These results imply that the space charge is unlikely the sole origin of the large current obstruction across the grain boundary in ceria-based solid electrolytes. PMID:27388961

  8. Potential for on-orbit manufacture of large space structures using the pultrusion process

    NASA Technical Reports Server (NTRS)

    Wilson, Maywood L.; Macconochie, Ian O.; Johnson, Gary S.

    1987-01-01

    On-orbit manufacture of lightweight, high-strength, advanced-composite structures using the pultrusion process is proposed. This process is adaptable to a zero-gravity environment by using preimpregnated graphite-fiber reinforcement systems. The reinforcement material is preimpregnated with a high-performance thermoplastic resin at a ground station, is coiled on spools for compact storage, and is transported into Earth orbit. A pultrusion machine is installed in the Shuttle cargo bay from which very long lengths of the desired structure is fabricated on-orbit. Potential structural profiles include rods, angles, channels, hat sections, tubes, honeycomb-cored panels, and T, H, and I beams. A potential pultrudable thermoplastic/graphite composite material is presented as a model for determining the effect on Earth-to-orbit package density of an on-orbit manufacture, the package density is increased by 132 percent, and payload volume requirement is decreased by 56.3 percent. The fabrication method has the potential for on-orbit manufacture of structural members for space platforms, large space antennas, and long tethers.

  9. Differences in seed rain composition in small and large fragments in the northeast Brazilian Atlantic Forest.

    PubMed

    Knörr, U C; Gottsberger, G

    2012-09-01

    Tropical forests are seriously threatened by fragmentation and habitat loss. The impact of fragment size and forest configuration on the composition of seed rain is insufficiently studied. For the present study, seed rain composition of small and large forest fragments (8-388 ha) was assessed in order to identify variations in seed abundance, species richness, seed size and dispersal mode. Seed rain was documented during a 1-year period in three large and four small Atlantic Forest fragments that are isolated by a sugarcane matrix. Total seed rain included 20,518 seeds of 149 species of trees, shrubs, palms, lianas and herbs. Most species and seeds were animal-dispersed. A significant difference in the proportion of seeds and species within different categories of seed size was found between small and large fragments. Small fragments received significantly more very small-sized seeds (<0.3 cm) and less large-seeded species (>1.5 cm) that were generally very rare, with only one species in small and eight in large fragments. We found a negative correlation between the inflow of small-sized seeds and the percentage of forest cover. Species richness was lower in small than in large fragments, but the difference was not very pronounced. Given our results, we propose changing plant species pools through logging, tree mortality and a high inflow of pioneer species and lianas, especially in small forest fragments and areas with low forest cover. Connecting forest fragments through corridors and reforestation with local large-seeded tree species may facilitate the maintenance of species diversity. PMID:22372687

  10. Large magnetocrystalline anisotropy in bilayer transition metal phases from first-principles full-potential calculations

    NASA Astrophysics Data System (ADS)

    Ravindran, P.; Kjekshus, A.; Fjellvåg, H.; James, P.; Nordström, L.; Johansson, B.; Eriksson, O.

    2001-04-01

    The computational framework of this study is based on the local-spin-density approximation with first-principles full-potential linear muffin-tin orbital calculations including orbital polarization (OP) correction. We have studied the magnetic anisotropy for a series of bilayer CuAu(I)-type materials such as FeX, MnX (X=Ni,Pd,Pt), CoPt, NiPt, MnHg, and MnRh in a ferromagnetic state using experimental structural parameters to understand the microscopic origin of magnetic-anisotropy energy (MAE) in magnetic multilayers. Except for MnRh and MnHg, all these phases show perpendicular magnetization. We have analyzed our results in terms of angular momentum-, spin- and site-projected density of states, magnetic-angular-momentum-projected density of states, orbital-moment density of states, and total density of states. The orbital-moment number of states and the orbital-moment anisotropy for FeX (X=Ni,Pd,Pt) are calculated as a function of band filling to study its effect on MAE. The total and site-projected spin and orbital moments for all these systems are calculated with and without OP when the magnetization is along or perpendicular to the plane. The results are compared with available experimental as well as theoretical results. Our calculations show that OP always enhances the orbital moment in these phases and brings them closer to experimental values. The changes in MAE are analyzed in terms of exchange splitting, spin-orbit splitting, and tetragonal distortion/crystal-field splitting. The calculated MAE is found to be in good agreement with experimental values when the OP correction is included. Some of the materials considered here show large magnetic anisotropy of the order of meV. In particular we found that MnPt will have a very large MAE if it could be stabilized in a ferromagnetic configuration. Our analysis indicates that apart from large spin-orbit interaction and exchange interaction from at least one of the constituents, a large crystal-field splitting

  11. Infants Use Different Mechanisms to Make Small and Large Number Ordinal Judgments

    ERIC Educational Resources Information Center

    vanMarle, Kristy

    2013-01-01

    Previous research has shown indirectly that infants may use two different mechanisms-an object tracking system and an analog magnitude mechanism--to represent small (less than 4) and large (greater than or equal to 4) numbers of objects, respectively. The current study directly tested this hypothesis in an ordinal choice task by presenting 10- to…

  12. Large differences in global and regional soil carbon stocks estimated by different products: intercomparison and evaluation with field measurements.

    NASA Astrophysics Data System (ADS)

    Tifafi, M.; Guenet, B.

    2015-12-01

    Soils are the major component of the terrestrial ecosystem and the largest organic carbon reservoir on Earth. However, it's a non-renewable natural resource and quite reactive to human disturbance and climate change. Even small modifications, of less than a percent, of the huge amount of carbon contained in soils may lead to sources or sinks of greenhouse gases that could be significant relative to those released by fossil fuel combustion. Consequently, soil carbon dynamic is an important source of uncertainties for future climate predictions. To tackle this difficulty, there is a growing need for global and specific information on the soils to better understand the mechanisms controlling soil carbon dynamic and better constraints the Earth system models. Several global information systems on soil parameters already exist but these products are not always consistent and lack of spatial details. The aim of our work is to compare the soil organic carbon stock given by different products : The World Soil Information (ISRIC), the Harmonized World Soil Database (HWSD) and The Northern Circumpolar Soil Carbon Database (NCSCD) and better understand what are the main differences that may explain the inconstencies between the products. We calculated global and regional soil carbon stocks with the three products at different depths and we observed that they may largely differ in particular in boreal regions. We also observed bigger differences in the stocks estimated for surface soils compare to deep soils. Differences in boreal regions may be due to high disparities in soil organic carbon concentration whereas differences in other regions may be more likely due to different bulk densities. Finally, we compared the three products with field data available within the International Soil Carbon Network and we observed that each products present important drawbacks in representing the spatial variability. The estimation of the global soil carbon stocks is still quite uncertain

  13. Carbon dioxide recycling: emerging large-scale technologies with industrial potential.

    PubMed

    Quadrelli, Elsje Alessandra; Centi, Gabriele; Duplan, Jean-Luc; Perathoner, Siglinda

    2011-09-19

    This Review introduces this special issue of ChemSusChem dedicated to CO(2) recycling. Its aim is to offer an up-to-date overview of CO(2) chemical utilization (inorganic mineralization, organic carboxylation, reduction reactions, and biochemical conversion), as a continuation and extension of earlier books and reviews on this topic, but with a specific focus on large-volume routes and projects/pilot plants that are currently emerging at (pre-)industrial level. The Review also highlights how some of these routes will offer a valuable opportunity to introduce renewable energy into the existing energy and chemical infrastructure (i.e., "drop-in" renewable energy) by synthesis of chemicals from CO(2) that are easy to transport and store. CO(2) conversion therefore has the potential to become a key pillar of the sustainable and resource-efficient production of chemicals and energy from renewables. PMID:21922677

  14. Large climate-moderating envelopes for enclosed structures: a preliminary evaluation of energy conservation potential

    SciTech Connect

    Wendt, R.L.; Giles, G.E.; Park, J.E.

    1981-12-01

    An investigation was made of the basic impacts of putting a large secondary enclosure around a number of functions and thereby creating a Large Climate Moderating Envelope (LCME). This study is a preliminary estimate of the energy conservation benefits of an LCME. A hypothetical LMCE design was chosen and a coupled fluid dynamic and energy transport analysis was performed to estimate the energy conservation potential of this design. The heat transfer models included insolation, outside air temperature and wind, thermal radiation exchange with the sky, and between the fabric and ground and thermal storage in the earth mass beneath the LCME. The energy transported within the fluid by the buoyancy driven circulation was modeled as an incompressible fluid utilizing the Boussinesq approximation. The climatic conditions were assumed to vary in smooth repeating daily cycles. The numerical simulation of climatic variation was continued until the results within the LCME achieved a repeating daily cycle. The results for selected seasonally characteristic days were utilized to estimate the annual energy consumption of structures within an LCME relative to similar structures exposed to the exterior environment. The relative annual energy savings for summer-dominated climates was estimated to be approx. 70%. The energy savings for a winter-dominated climate LCME were estimated to be somewhat smaller but the LCME concept could offer significant benefits for agricultural applications for this type of climate.

  15. Toward large N thermal QCD from dual gravity: The heavy quarkonium potential

    SciTech Connect

    Mia, Mohammed; Dasgupta, Keshav; Gale, Charles; Jeon, Sangyong

    2010-07-15

    We continue our study on the gravity duals for strongly coupled large N QCD with fundamental flavors both at zero and nonzero temperatures. The gravity dual at zero temperature captures the logarithmic runnings of the coupling constants at far IR and the almost conformal, albeit strongly coupled, behavior at the UV. The full UV completion of gauge theory is accomplished in the gravity side by attaching an anti-de Sitter cap to the IR geometry described in our previous work. Attaching such an anti-de Sitter cap is highly nontrivial because it amounts to finding the right interpolating geometry and sources that take us from a gravity solution with nonzero three-form fluxes to another one that has almost vanishing three-form fluxes. In this paper we give a concrete realization of such a scenario, completing the program advocated in our earlier paper. One of the main advantages of having such a background, in addition to providing a dual description of the required gauge theory, is the absence of Landau poles and consequently the UV divergences of the Wilson loops. The potential for the heaviest fundamental quark-antiquark pairs, which are like the heavy quarkonium states in realistic QCD, can be computed and their linear behavior at large separations and zero temperature could be demonstrated. At small separations the expected Coulombic behavior appears to dominate. On the other hand, at nonzero temperatures interesting properties like heavy quarkonium-type suppressions and melting are shown to emerge from our gravity dual. We provide some discussions of the melting temperature and compare our results with the charmonium spectrum and lattice simulations. We argue that, in spite of the large N nature of our construction, certain model-independent predictions can be made.

  16. Large Differences in Bacterial Community Composition among Three Nearby Extreme Waterbodies of the High Andean Plateau

    PubMed Central

    Aguilar, Pablo; Acosta, Eduardo; Dorador, Cristina; Sommaruga, Ruben

    2016-01-01

    The high Andean plateau or Altiplano contains different waterbodies that are subjected to extreme fluctuations in abiotic conditions on a daily and an annual scale. The bacterial diversity and community composition of those shallow waterbodies is largely unexplored, particularly, of the ponds embedded within the peatland landscape (i.e., Bofedales). Here we compare the small-scale spatial variability (<1 m) in bacterial diversity and community composition between two of those ponds with contrasting apparent color, using 454 pyrosequencing of the 16S rRNA gene. Further, we compared the results with the nearest (80 m) main lagoon in the system to elucidate the importance of different environmental factors such as salinity and the importance of these ponds as a source of shared diversity. Bacterial diversity was higher in both ponds than in the lagoon and community composition was largely different among them and characterized by very low operational taxonomic unit sharing. Whereas the “green” pond with relatively low dissolved organic carbon (DOC) concentration (33.5 mg L-1) was dominated by Proteobacteria and Bacteroidetes, the one with extreme DOC concentration (424.1 mg L-1) and red hue was dominated by Cyanobacteria. By contrast, the lagoon was largely dominated by Proteobacteria, particularly by Gammaproteobacteria. A large percentage (47%) of all reads was unclassified suggesting the existence of large undiscovered bacterial diversity. Our results suggest that even at the very small-scale spatial range considered, local environmental factors are important in explaining differences in bacterial community composition in those systems. Further, our study highlights that Altiplano peatland ponds represent a hitherto unknown source of microbial diversity. PMID:27446017

  17. Large Differences in Bacterial Community Composition among Three Nearby Extreme Waterbodies of the High Andean Plateau.

    PubMed

    Aguilar, Pablo; Acosta, Eduardo; Dorador, Cristina; Sommaruga, Ruben

    2016-01-01

    The high Andean plateau or Altiplano contains different waterbodies that are subjected to extreme fluctuations in abiotic conditions on a daily and an annual scale. The bacterial diversity and community composition of those shallow waterbodies is largely unexplored, particularly, of the ponds embedded within the peatland landscape (i.e., Bofedales). Here we compare the small-scale spatial variability (<1 m) in bacterial diversity and community composition between two of those ponds with contrasting apparent color, using 454 pyrosequencing of the 16S rRNA gene. Further, we compared the results with the nearest (80 m) main lagoon in the system to elucidate the importance of different environmental factors such as salinity and the importance of these ponds as a source of shared diversity. Bacterial diversity was higher in both ponds than in the lagoon and community composition was largely different among them and characterized by very low operational taxonomic unit sharing. Whereas the "green" pond with relatively low dissolved organic carbon (DOC) concentration (33.5 mg L(-1)) was dominated by Proteobacteria and Bacteroidetes, the one with extreme DOC concentration (424.1 mg L(-1)) and red hue was dominated by Cyanobacteria. By contrast, the lagoon was largely dominated by Proteobacteria, particularly by Gammaproteobacteria. A large percentage (47%) of all reads was unclassified suggesting the existence of large undiscovered bacterial diversity. Our results suggest that even at the very small-scale spatial range considered, local environmental factors are important in explaining differences in bacterial community composition in those systems. Further, our study highlights that Altiplano peatland ponds represent a hitherto unknown source of microbial diversity. PMID:27446017

  18. Potential consequences of climate change for primary production and fish production in large marine ecosystems

    PubMed Central

    Blanchard, Julia L.; Jennings, Simon; Holmes, Robert; Harle, James; Merino, Gorka; Allen, J. Icarus; Holt, Jason; Dulvy, Nicholas K.; Barange, Manuel

    2012-01-01

    Existing methods to predict the effects of climate change on the biomass and production of marine communities are predicated on modelling the interactions and dynamics of individual species, a very challenging approach when interactions and distributions are changing and little is known about the ecological mechanisms driving the responses of many species. An informative parallel approach is to develop size-based methods. These capture the properties of food webs that describe energy flux and production at a particular size, independent of species' ecology. We couple a physical–biogeochemical model with a dynamic, size-based food web model to predict the future effects of climate change on fish biomass and production in 11 large regional shelf seas, with and without fishing effects. Changes in potential fish production are shown to most strongly mirror changes in phytoplankton production. We project declines of 30–60% in potential fish production across some important areas of tropical shelf and upwelling seas, most notably in the eastern Indo-Pacific, the northern Humboldt and the North Canary Current. Conversely, in some areas of the high latitude shelf seas, the production of pelagic predators was projected to increase by 28–89%. PMID:23007086

  19. The potential relevance of the endocannabinoid, 2-arachidonoylglycerol, in diffuse large B-cell lymphoma

    PubMed Central

    Zhang, Jianqing; Medina-Cleghorn, Daniel; Bernal-Mizrachi, Leon; Bracci, Paige M.; Hubbard, Alan; Conde, Lucia; Riby, Jacques; Nomura, Daniel K.; Skibola, Christine F.

    2016-01-01

    Diffuse large B-cell lymphoma is an aggressive, genetically heterogenerous disease and the most common type of non-Hodgkin lymphoma among adults. To gain further insights into the etiology of DLBCL and to discover potential disease-related factors, we performed a serum lipid analysis on a subset of individuals from a population-based NHL case-control study. An untargeted mass-spectrometry-based metabolomics platform was used to analyze serum samples from 100 DLBCL patients and 100 healthy matched controls. Significantly elevated levels of the endocannabinoid, 2-arachidonoylglycerol (2-AG), were detected in the serum of DLBCL patients (121%, P < 0.05). In the male controls, elevated 2-AG levels were observed in those who were overweight (BMI ≥ 25 - < 30 kg/m2; 108%, P < 0.01) and obese (BMI ≥ 30 kg/m2; 118%, P < 0.001) compared to those with a BMI < 25 kg/m2. DLBCL cell lines treated with exogenous 2-AG across a range of concentrations, exhibited heterogenous responses: proliferation rates were markedly higher in 4 cell lines by 22%-68% (P < 0.001) and lower in 8 by 20%-75% (P < 0.001). The combined findings of elevated 2-AG levels in DLBCL patients and the proliferative effects of 2-AG on a subset of DLBCL cell lines suggests that 2-AG may play a potential role in the pathogenesis or progression of a subset of DLBCLs. PMID:26973858

  20. Radiometric Normalization of Large Airborne Image Data Sets Acquired by Different Sensor Types

    NASA Astrophysics Data System (ADS)

    Gehrke, S.; Beshah, B. T.

    2016-06-01

    Generating seamless mosaics of aerial images is a particularly challenging task when the mosaic comprises a large number of im-ages, collected over longer periods of time and with different sensors under varying imaging conditions. Such large mosaics typically consist of very heterogeneous image data, both spatially (different terrain types and atmosphere) and temporally (unstable atmo-spheric properties and even changes in land coverage). We present a new radiometric normalization or, respectively, radiometric aerial triangulation approach that takes advantage of our knowledge about each sensor's properties. The current implementation supports medium and large format airborne imaging sensors of the Leica Geosystems family, namely the ADS line-scanner as well as DMC and RCD frame sensors. A hierarchical modelling - with parameters for the overall mosaic, the sensor type, different flight sessions, strips and individual images - allows for adaptation to each sensor's geometric and radiometric properties. Additional parameters at different hierarchy levels can compensate radiome-tric differences of various origins to compensate for shortcomings of the preceding radiometric sensor calibration as well as BRDF and atmospheric corrections. The final, relative normalization is based on radiometric tie points in overlapping images, absolute radiometric control points and image statistics. It is computed in a global least squares adjustment for the entire mosaic by altering each image's histogram using a location-dependent mathematical model. This model involves contrast and brightness corrections at radiometric fix points with bilinear interpolation for corrections in-between. The distribution of the radiometry fixes is adaptive to each image and generally increases with image size, hence enabling optimal local adaptation even for very long image strips as typi-cally captured by a line-scanner sensor. The normalization approach is implemented in HxMap software. It has been

  1. Fabrication of large size graphene and Ti- MWCNTs/ large size graphene composites: their photocatalytic properties and potential application

    PubMed Central

    Ullah, Kefayat; Oh, Won-Chun

    2015-01-01

    Large size graphene (LSG) and multiwall carbon nanotubes (MWCNTs) on LSG were synthesized on a copper surface via chemical vapor deposition (CVD) at low temperature and normal pressure. The LSG were formed through an easy chemical cyclic reaction in which liquid benzene was heated to a temperature below its boiling point to create benzene vapors as graphene precursor material. The reaction mechanism was observed, and the time-dependent analysis of the reaction revealed that mounds of the carbon nanotubes had grown as a result of the island that was found on the LSG sheet. The implications of the mechanism that we have introduced were investigated by coating a titanium sheet on the MWCNTs/LSG and LSG on the semiconductor electronic device. The photonic response was observed to be markedly high, which can be attributed to the positive synergetic effect between the Ti and LSG sheet of our prepared composites. PMID:26384216

  2. Fabrication of large size graphene and Ti- MWCNTs/ large size graphene composites: their photocatalytic properties and potential application

    NASA Astrophysics Data System (ADS)

    Ullah, Kefayat; Oh, Won-Chun

    2015-09-01

    Large size graphene (LSG) and multiwall carbon nanotubes (MWCNTs) on LSG were synthesized on a copper surface via chemical vapor deposition (CVD) at low temperature and normal pressure. The LSG were formed through an easy chemical cyclic reaction in which liquid benzene was heated to a temperature below its boiling point to create benzene vapors as graphene precursor material. The reaction mechanism was observed, and the time-dependent analysis of the reaction revealed that mounds of the carbon nanotubes had grown as a result of the island that was found on the LSG sheet. The implications of the mechanism that we have introduced were investigated by coating a titanium sheet on the MWCNTs/LSG and LSG on the semiconductor electronic device. The photonic response was observed to be markedly high, which can be attributed to the positive synergetic effect between the Ti and LSG sheet of our prepared composites.

  3. Fabrication of large size graphene and Ti- MWCNTs/ large size graphene composites: their photocatalytic properties and potential application.

    PubMed

    Ullah, Kefayat; Oh, Won-Chun

    2015-01-01

    Large size graphene (LSG) and multiwall carbon nanotubes (MWCNTs) on LSG were synthesized on a copper surface via chemical vapor deposition (CVD) at low temperature and normal pressure. The LSG were formed through an easy chemical cyclic reaction in which liquid benzene was heated to a temperature below its boiling point to create benzene vapors as graphene precursor material. The reaction mechanism was observed, and the time-dependent analysis of the reaction revealed that mounds of the carbon nanotubes had grown as a result of the island that was found on the LSG sheet. The implications of the mechanism that we have introduced were investigated by coating a titanium sheet on the MWCNTs/LSG and LSG on the semiconductor electronic device. The photonic response was observed to be markedly high, which can be attributed to the positive synergetic effect between the Ti and LSG sheet of our prepared composites. PMID:26384216

  4. Multiple mechanisms involved in the large-spectrum therapeutic potential of cannabidiol in psychiatric disorders.

    PubMed

    Campos, Alline Cristina; Moreira, Fabricio Araújo; Gomes, Felipe Villela; Del Bel, Elaine Aparecida; Guimarães, Francisco Silveira

    2012-12-01

    Cannabidiol (CBD) is a major phytocannabinoid present in the Cannabis sativa plant. It lacks the psychotomimetic and other psychotropic effects that the main plant compound Δ(9)-tetrahydrocannabinol (THC) being able, on the contrary, to antagonize these effects. This property, together with its safety profile, was an initial stimulus for the investigation of CBD pharmacological properties. It is now clear that CBD has therapeutic potential over a wide range of non-psychiatric and psychiatric disorders such as anxiety, depression and psychosis. Although the pharmacological effects of CBD in different biological systems have been extensively investigated by in vitro studies, the mechanisms responsible for its therapeutic potential are still not clear. Here, we review recent in vivo studies indicating that these mechanisms are not unitary but rather depend on the behavioural response being measured. Acute anxiolytic and antidepressant-like effects seem to rely mainly on facilitation of 5-HT1A-mediated neurotransmission in key brain areas related to defensive responses, including the dorsal periaqueductal grey, bed nucleus of the stria terminalis and medial prefrontal cortex. Other effects, such as anti-compulsive, increased extinction and impaired reconsolidation of aversive memories, and facilitation of adult hippocampal neurogenesis could depend on potentiation of anandamide-mediated neurotransmission. Finally, activation of TRPV1 channels may help us to explain the antipsychotic effect and the bell-shaped dose-response curves commonly observed with CBD. Considering its safety profile and wide range of therapeutic potential, however, further studies are needed to investigate the involvement of other possible mechanisms (e.g. inhibition of adenosine uptake, inverse agonism at CB2 receptor, CB1 receptor antagonism, GPR55 antagonism, PPARγ receptors agonism, intracellular (Ca(2+)) increase, etc.), on CBD behavioural effects. PMID:23108553

  5. Multiple mechanisms involved in the large-spectrum therapeutic potential of cannabidiol in psychiatric disorders

    PubMed Central

    Campos, Alline Cristina; Moreira, Fabricio Araújo; Gomes, Felipe Villela; Del Bel, Elaine Aparecida; Guimarães, Francisco Silveira

    2012-01-01

    Cannabidiol (CBD) is a major phytocannabinoid present in the Cannabis sativa plant. It lacks the psychotomimetic and other psychotropic effects that the main plant compound Δ9-tetrahydrocannabinol (THC) being able, on the contrary, to antagonize these effects. This property, together with its safety profile, was an initial stimulus for the investigation of CBD pharmacological properties. It is now clear that CBD has therapeutic potential over a wide range of non-psychiatric and psychiatric disorders such as anxiety, depression and psychosis. Although the pharmacological effects of CBD in different biological systems have been extensively investigated by in vitro studies, the mechanisms responsible for its therapeutic potential are still not clear. Here, we review recent in vivo studies indicating that these mechanisms are not unitary but rather depend on the behavioural response being measured. Acute anxiolytic and antidepressant-like effects seem to rely mainly on facilitation of 5-HT1A-mediated neurotransmission in key brain areas related to defensive responses, including the dorsal periaqueductal grey, bed nucleus of the stria terminalis and medial prefrontal cortex. Other effects, such as anti-compulsive, increased extinction and impaired reconsolidation of aversive memories, and facilitation of adult hippocampal neurogenesis could depend on potentiation of anandamide-mediated neurotransmission. Finally, activation of TRPV1 channels may help us to explain the antipsychotic effect and the bell-shaped dose-response curves commonly observed with CBD. Considering its safety profile and wide range of therapeutic potential, however, further studies are needed to investigate the involvement of other possible mechanisms (e.g. inhibition of adenosine uptake, inverse agonism at CB2 receptor, CB1 receptor antagonism, GPR55 antagonism, PPARγ receptors agonism, intracellular (Ca2+) increase, etc.), on CBD behavioural effects. PMID:23108553

  6. a Direct Probe for Chemical Potentials Difference Between Neutron and Protons in Heavy-Ion Collisions

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Zhang, Yan-Li; Wang, Shan-Shan

    We briefly introduce the newly proposed probe to the neutron and proton chemical potential (and density) difference, which is called as the isobaric yield ratio difference (IBD). The IBD probe is related to the chemical potential difference of neutrons and protons between two reactions, at the same time, the nuclear density difference between two reactions. The relationship between the IBD probe and the isoscaling method has also been discussed.

  7. Intra- and interspecific differences in diet quality and composition in a large herbivore community.

    PubMed

    Redjadj, Claire; Darmon, Gaëlle; Maillard, Daniel; Chevrier, Thierry; Bastianelli, Denis; Verheyden, Hélène; Loison, Anne; Saïd, Sonia

    2014-01-01

    Species diversity in large herbivore communities is often explained by niche segregation allowed by differences in body mass and digestive morphophysiological features. Based on large number of gut samples in fall and winter, we analysed the temporal dynamics of diet composition, quality and interspecific overlap of 4 coexisting mountain herbivores. We tested whether the relative consumption of grass and browse differed among species of different rumen types (moose-type and intermediate-type), whether diet was of lower quality for the largest species, whether we could identify plant species which determined diet quality, and whether these plants, which could be "key-food-resources" were similar for all herbivores. Our analyses revealed that (1) body mass and rumen types were overall poor predictors of diet composition and quality, although the roe deer, a species with a moose-type rumen was confirmed as an "obligatory non grazer", while red deer, the largest species, had the most lignified diet; (2) diet overlap among herbivores was well predicted by rumen type (high among species of intermediate types only), when measured over broad plant groups, (3) the relationship between diet composition and quality differed among herbivore species, and the actual plant species used during winter which determined the diet quality, was herbivore species-specific. Even if diets overlapped to a great extent, the species-specific relationships between diet composition and quality suggest that herbivores may select different plant species within similar plant group types, or different plant parts and that this, along with other behavioural mechanisms of ecological niche segregation, may contribute to the coexistence of large herbivores of relatively similar body mass, as observed in mountain ecosystems. PMID:24586233

  8. Large eddy simulation of zero-pressure-gradient turbulent boundary layer based on different scaling laws

    NASA Astrophysics Data System (ADS)

    Cheng, Wan; Samtaney, Ravi

    2013-11-01

    We present results of large eddy simulation (LES) for a smooth-wall, zero-pressure-gradient turbulent boundary layer. We employ the stretched vortex sub-grid-scale model in the simulations augmented by a wall model. Our wall model is based on the virtual-wall model introduced by Chung & Pullin (J. Fluid Mech 2009). An essential component of their wall model is an ODE governing the local wall-normal velocity gradient obtained using inner-scaling ansatz. We test two variants of the wall model based on different similarity laws: one is based on a log-law and the other on a power-law. The specific form of the power law scaling utilized is that proposed by George & Castillo (Appl. Mech. Rev. 1997), dubbed the ``GC Law''. Turbulent inflow conditions are generated by a recycling method, and applying scaling laws corresponding to the two variants of the wall model, and a uniform way to determine the inlet friction velocity. For Reynolds number based on momentum thickness, Reθ , ranging from 104 to 1012 it is found that the velocity profiles generally follow the log law form rather than the power law. For large Reynolds number asymptotic behavior, LES based on different scaling laws the boundary layer thickness and turbulent intensities do not show much difference. Supported by a KAUST funded project on large eddy simulation of turbulent flows. The IBM Blue Gene P Shaheen at KAUST was utilized for the simulations.

  9. Potential and attainable food production and food security in different regions

    PubMed Central

    Vries, F. W. T. Penning de; Rabbinge, R.; Groot, J. J. R.

    1997-01-01

    Growing prosperity in the South is accompanied by human diets that will claim more natural resources per capita. This reality, combined with growing populations, may raise the global demand for food crops two- to four-fold within two generations. Considering the large volume of natural resources and potential crop yields, it seems that this demand can be met smoothly. However, this is a fallacy for the following reasons. (i) Geographic regions differ widely in their potential food security: policy choices for agricultural use of natural resources are limited in Asia. For example, to ensure national self-sufficiency and food security, most of the suitable land (China) and nearly all of the surface water (India) are needed. Degradation restricts options further. (ii) The attainable level of agricultural production depends also on socio-economic conditions. Extensive poverty keeps the attainable food production too low to achieve food security, even when the yield gap is wide, as in Africa. (iii) Bio-energy, non-food crops and nature compete with food crops for natural resources. Global and regional food security are attainable, but only with major efforts. Strategies to achieve alternative aims will be discussed.

  10. Detecting and developing youth athlete potential: different strokes for different folks are warranted.

    PubMed

    Suppiah, Haresh T; Low, Chee Yong; Chia, Michael

    2015-07-01

    Sport talent identification and development (TI and TD) in youth continues to attract strong interest among coaches, sport scientists and sport administrators. TI for sport in youth with the anticipation of future elite level sport achievement is both an art and a science, and is strongly influenced by within athlete and extraneous-to-athlete factors (ecosystem of support or the lack of). The returns from investment on current TI and TD models of sport in youth are subpar in that few continue in the sport to achieve podium positions at the elite sport level in adulthood. Why, where and how one succeeds in sport, and what that success means to the athlete and stakeholders are dependent on the culture and context of the country. We advocate harnessing the power of sport to help in youth development, to be holistic in its nurturance, to allow for individual idiosyncratic expressions of the athletes, to provide for talent transfer across sport, and to facilitate key stakeholders to 'join' hands to work for the common interest and understanding for as many youth and adults so as to provide them with opportunities through support and coaching to compete at the different levels of competition in sport. Governments, policy makers and administrators of sport must decide, within their specific circumstances, if TI and TD in sport in youth is serving a meaningful purpose and is a viable return on investment; in short, is it mission possible or is it… a quest for the Holy Grail for a podium finish in elite level sport competition? PMID:25907182

  11. The Potential of Unmanned Aerial Vehicle for Large Scale Mapping of Coastal Area

    NASA Astrophysics Data System (ADS)

    Darwin, N.; Ahmad, A.; Zainon, O.

    2014-02-01

    Many countries in the tropical region are covered with cloud for most of the time, hence, it is difficult to get clear images especially from high resolution satellite imagery. Aerial photogrammetry can be used but most of the time the cloud problem still exists. Today, this problem could be solved using a system known as unmanned aerial vehicle (UAV) where the aerial images can be acquired at low altitude and the system can fly under the cloud. The UAV system could be used in various applications including mapping coastal area. The UAV system is equipped with an autopilot system and automatic method known as autonomous flying that can be utilized for data acquisition. To achieve high resolution imagery, a compact digital camera of high resolution was used to acquire the aerial images at an altitude. In this study, the UAV system was employed to acquire aerial images of a coastal simulation model at low altitude. From the aerial images, photogrammetric image processing was executed to produce photogrammetric outputs such a digital elevation model (DEM), contour line and orthophoto. In this study, ground control point (GCP) and check point (CP) were established using conventional ground surveying method (i.e total station). The GCP is used for exterior orientation in photogrammetric processes and CP for accuracy assessment based on Root Mean Square Error (RMSE). From this study, it was found that the UAV system can be used for large scale mapping of coastal simulation model with accuracy at millimeter level. It is anticipated that the same system could be used for large scale mapping of real coastal area and produces good accuracy. Finally, the UAV system has great potential to be used for various applications that require accurate results or products at limited time and less man power.

  12. Potential energy savings with exterior shades in large office buildings and the impact of discomfort glare

    SciTech Connect

    Hoffmann, Sabine; Lee, Eleanor

    2015-04-01

    Exterior shades are highly efficient for reducing solar load in commercial buildings. Their impact on net energy use depends on the annual energy balance of heating, cooling, fan and lighting energy. This paper discusses the overall energy use intensity of various external shading systems for a prototypical large office building split into the different types of energy use and for different orientations and window sizes. Lighting energy was calculated for a constant lighting power as well as for dimmed lighting fixtures (daylighting control). In Section 3, slat angles and solar cut-off angles were varied for fixed exterior slat shading systems. While the most light-blocking shades performed best for the case without daylighting controls, the optimum cut-off angle with daylighting controls was found to be 30 deg for the office building prototype used in Chicago and Houston. For large window-to-wall (WWR) ratios, window related annual energy use could be reduced by at least 70 % without daylighting control and by a minimum of 86 % with daylighting control in average over all orientations. The occurrence of discomfort glare was is considered in Section 4 of the paper, which looks at the performance of commercially available exterior shading systems when an interior shade is used in addition to the exterior shade during hours when occupants would experience discomfort glare. Glare control impacts overall energy use intensity significantly for exterior shades with high transmittance, especially when daylighting controls are used. In these cases, exterior shades are only beneficial for window-to-wall areas ≥ 45% in the hot Houston climate. For smaller windows and in a heating/cooling climate like Chicago, exterior shades can increase energy consumption

  13. Potential for Large Transpressional Earthquakes along the Santa Cruz-Catalina Ridge, California Continental Borderland

    NASA Astrophysics Data System (ADS)

    Legg, M.; Kohler, M. D.; Weeraratne, D. S.; Castillo, C. M.

    2015-12-01

    Transpressional fault systems comprise networks of high-angle strike-slip and more gently-dipping oblique-slip faults. Large oblique-slip earthquakes may involve complex ruptures of multiple faults with both strike-slip and dip-slip. Geophysical data including high-resolution multibeam bathymetry maps, multichannel seismic reflection (MCS) profiles, and relocated seismicity catalogs enable detailed mapping of the 3-D structure of seismogenic fault systems offshore in the California Continental Borderland. Seafloor morphology along the San Clemente fault system displays numerous features associated with active strike-slip faulting including scarps, linear ridges and valleys, and offset channels. Detailed maps of the seafloor faulting have been produced along more than 400 km of the fault zone. Interpretation of fault geometry has been extended to shallow crustal depths using 2-D MCS profiles and to seismogenic depths using catalogs of relocated southern California seismicity. We examine the 3-D fault character along the transpressional Santa Cruz-Catalina Ridge (SCCR) section of the fault system to investigate the potential for large earthquakes involving multi-fault ruptures. The 1981 Santa Barbara Island (M6.0) earthquake was a right-slip event on a vertical fault zone along the northeast flank of the SCCR. Aftershock hypocenters define at least three sub-parallel high-angle fault surfaces that lie beneath a hillside valley. Mainshock rupture for this moderate earthquake appears to have been bilateral, initiating at a small discontinuity in the fault geometry (~5-km pressure ridge) near Kidney Bank. The rupture terminated to the southeast at a significant releasing step-over or bend and to the northeast within a small (~10-km) restraining bend. An aftershock cluster occurred beyond the southeast asperity along the East San Clemente fault. Active transpression is manifest by reverse-slip earthquakes located in the region adjacent to the principal displacement zone

  14. On the Definition of Surface Potentials for Finite-Difference Operators

    NASA Technical Reports Server (NTRS)

    Tsynkov, S. V.; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    For a class of linear constant-coefficient finite-difference operators of the second order, we introduce the concepts similar to those of conventional single- and double-layer potentials for differential operators. The discrete potentials are defined completely independently of any notion related to the approximation of the continuous potentials on the grid. We rather use all approach based on differentiating, and then inverting the differentiation of a function with surface discontinuity of a particular kind, which is the most general way of introducing surface potentials in the theory of distributions. The resulting finite-difference "surface" potentials appear to be solutions of the corresponding continuous potentials. Primarily, this pertains to the possibility of representing a given solution to the homogeneous equation on the domain as a variety of surface potentials, with the density defined on the domain's boundary. At the same time the discrete surface potentials can be interpreted as one specific realization of the generalized potentials of Calderon's type, and consequently, their approximation properties can be studied independently in the framework of the difference potentials method by Ryaben'kii. The motivation for introducing and analyzing the discrete surface potentials was provided by the problems of active shielding and control of sound, in which the aforementioned source terms that drive the potentials are interpreted as the acoustic control sources that cancel out the unwanted noise on a predetermined region of interest.

  15. Large extracellular loop of tetraspanin as a potential vaccine candidate for filariasis.

    PubMed

    Dakshinamoorthy, Gajalakshmi; Munirathinam, Gnanasekar; Stoicescu, Kristen; Reddy, Maryada Venkatarami; Kalyanasundaram, Ramaswamy

    2013-01-01

    Lymphatic filariasis affects nearly 120 million people worldwide and mass preventive chemotherapy is currently used as a strategy to control this infection. This has substantially reduced the incidence of the infection in several parts of the world. However, a prophylactic vaccine would be more effective in preventing future infections and will supplement the mass chemotherapy efforts. Unfortunately, there is no licensed vaccine available currently to prevent this infection. Molecules expressed on the surface of the parasite are potential candidates for vaccine development as they are exposed to the host immune system. In this study we show that the large extracellular loop of tetraspanin (TSP LEL), a protein expressed on the cuticle of Brugia malayi and Wuchereria bancrofti is a potential vaccine candidate. Our results showed that BmTSP LEL is expressed on the surface of B. malayi infective third stage larvae (L3) and sera from human subjects who are putatively immune to lymphatic filariasis carry high titer of IgG1 and IgG3 antibodies against BmTSP LEL and WbTSP LEL. We also showed that these antibodies in the sera of human subjects can participate in the killing of B. malayi L3 in an antibody dependent cell-mediated cytotoxicity mechanism. Vaccination trials in mice showed that close to 64% protection were achieved against challenge infections with B. malayi L3. Immunized animals showed high titer of anti-WbTSP LEL IgG1, IgG2a and IgG2b antibodies in the sera and IFN-γ secreting cells in the spleen. Onchocerca volvulus another filarial parasite also expresses TSP LEL. Cross-reactivity studies showed that IgG1 antibody in the sera of endemic normal subjects, recognize OvTSP LEL. Similarly, anti-OvTSP LEL antibodies in the sera of subjects who are immune to O. volvulus were also shown to cross-react with rWbTSP LEL and rBmTSP LEL. These findings thus suggested that rTSP LEL can be developed as a potential vaccine candidate against multiple filarial infections

  16. Diffuse large B-cell lymphoma in the elderly: a review of potential difficulties.

    PubMed

    Sarkozy, Clémentine; Coiffier, Bertrand

    2013-04-01

    Half of patients with diffuse large B-cell lymphoma (DLBCL) are more than 65 years old. These elderly patients frequently have other diseases, some of them severe, which may alter their ability to receive standard curative therapy. However, these associated diseases are heterogeneous and only a few contraindicate chemotherapy treatments. We reviewed all potential difficulties, such as the evaluation of comorbidities, the heterogeneous functional status of this population, and the consequences of the aging process that might be associated with treating these patients, and now propose solutions. As standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy may cure the majority of patients, it must always be the first proposed option. With this approach, elderly patients with DLBCL treated with a curative intent can reach a complete remission and have a similar outcome as younger patients. Reduced dose intensity must be applied for very elderly patients or those unfit for full-dose anthracycline. The critical question for a physician is why these patients cannot be treated with the standard regimen, namely R-CHOP. PMID:23339126

  17. Towards stable kinetics of large metabolic networks: Nonequilibrium potential function approach

    NASA Astrophysics Data System (ADS)

    Chen, Yong-Cong; Yuan, Ruo-Shi; Ao, Ping; Xu, Min-Juan; Zhu, Xiao-Mei

    2016-06-01

    While the biochemistry of metabolism in many organisms is well studied, details of the metabolic dynamics are not fully explored yet. Acquiring adequate in vivo kinetic parameters experimentally has always been an obstacle. Unless the parameters of a vast number of enzyme-catalyzed reactions happened to fall into very special ranges, a kinetic model for a large metabolic network would fail to reach a steady state. In this work we show that a stable metabolic network can be systematically established via a biologically motivated regulatory process. The regulation is constructed in terms of a potential landscape description of stochastic and nongradient systems. The constructed process draws enzymatic parameters towards stable metabolism by reducing the change in the Lyapunov function tied to the stochastic fluctuations. Biologically it can be viewed as interplay between the flux balance and the spread of workloads on the network. Our approach allows further constraints such as thermodynamics and optimal efficiency. We choose the central metabolism of Methylobacterium extorquens AM1 as a case study to demonstrate the effectiveness of the approach. Growth efficiency on carbon conversion rate versus cell viability and futile cycles is investigated in depth.

  18. Design of a Computerised Flight Mill Device to Measure the Flight Potential of Different Insects.

    PubMed

    Martí-Campoy, Antonio; Ávalos, Juan Antonio; Soto, Antonia; Rodríguez-Ballester, Francisco; Martínez-Blay, Victoria; Malumbres, Manuel Pérez

    2016-01-01

    Several insect species pose a serious threat to different plant species, sometimes becoming a pest that produces significant damage to the landscape, biodiversity, and/or the economy. This is the case of Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae), Semanotus laurasii Lucas (Coleoptera: Cerambycidae), and Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae), which have become serious threats to ornamental and productive trees all over the world such as palm trees, cypresses, and pines. Knowledge about their flight potential is very important for designing and applying measures targeted to reduce the negative effects from these pests. Studying the flight capability and behaviour of some insects is difficult due to their small size and the large area wherein they can fly, so we wondered how we could obtain information about their flight capabilities in a controlled environment. The answer came with the design of flight mills. Relevant data about the flight potential of these insects may be recorded and analysed by means of a flight mill. Once an insect is attached to the flight mill, it is able to fly in a circular direction without hitting walls or objects. By adding sensors to the flight mill, it is possible to record the number of revolutions and flight time. This paper presents a full description of a computer monitored flight mill. The description covers both the mechanical and the electronic parts in detail. The mill was designed to easily adapt to the anatomy of different insects and was successfully tested with individuals from three species R. ferrugineus, S. laurasii, and M. galloprovincialis. PMID:27070600

  19. Design of a Computerised Flight Mill Device to Measure the Flight Potential of Different Insects

    PubMed Central

    Martí-Campoy, Antonio; Ávalos, Juan Antonio; Soto, Antonia; Rodríguez-Ballester, Francisco; Martínez-Blay, Victoria; Malumbres, Manuel Pérez

    2016-01-01

    Several insect species pose a serious threat to different plant species, sometimes becoming a pest that produces significant damage to the landscape, biodiversity, and/or the economy. This is the case of Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae), Semanotus laurasii Lucas (Coleoptera: Cerambycidae), and Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae), which have become serious threats to ornamental and productive trees all over the world such as palm trees, cypresses, and pines. Knowledge about their flight potential is very important for designing and applying measures targeted to reduce the negative effects from these pests. Studying the flight capability and behaviour of some insects is difficult due to their small size and the large area wherein they can fly, so we wondered how we could obtain information about their flight capabilities in a controlled environment. The answer came with the design of flight mills. Relevant data about the flight potential of these insects may be recorded and analysed by means of a flight mill. Once an insect is attached to the flight mill, it is able to fly in a circular direction without hitting walls or objects. By adding sensors to the flight mill, it is possible to record the number of revolutions and flight time. This paper presents a full description of a computer monitored flight mill. The description covers both the mechanical and the electronic parts in detail. The mill was designed to easily adapt to the anatomy of different insects and was successfully tested with individuals from three species R. ferrugineus, S. laurasii, and M. galloprovincialis. PMID:27070600

  20. How large are uncertainties in future projection of reference evapotranspiration through different approaches?

    NASA Astrophysics Data System (ADS)

    Wang, Weiguang; Xing, Wanqiu; Shao, Quanxi

    2015-05-01

    As the indicator of atmospheric evaporative demand over a hypothetical reference surface, reference evapotranspiration (ET0) is an important input to hydrological models. Future projections of ET0 are of great importance in assessing the potential impacts of climate change on the hydrologic regime as well as water resources systems. Different estimating formulations and different input data reliabilities existing in practice determine there may be potential uncertainty in projection of future ET0 change. Here we investigated the difference of future ET0 response to climate change based on three approaches, i.e., more physically based Penman-Montieth equation with relatively uncertain downscaled data quality, more empirical temperature-based Hargreaves equation with more reliable downscaled input data, and statistical downscaling method with directly selecting ET0 as predictands. The Hanjiang River Basin, a headwater source of famous South to North Water Diversion Project (SNWDP) in China was chosen as example to illustrate this issue. Although similar increase processes of ET0 in the Hanjiang River Basin were suggested by three methods, the magnitude of ET0 increase differs substantially, indicating that uncertainty still exist despite of approximate performance of these methods in simulating general trends. Whilst increasing aridity index and decreasing water surplus over the period of 2011-2099 would inevitably cause negative impacts on the implementation of the SNWDP and effective adapting measures are thus expected.

  1. Large Eddy Simulation of Compressible Flow past an Oscillating Cylinder using the Spectral Difference Method

    NASA Astrophysics Data System (ADS)

    Cox, Christopher; Liang, Chunlei

    2011-11-01

    In this investigation, we implement a high-order three-dimensional spectral difference (SD) method to solve the compressible Navier-Stokes equations on an unstructured moving deformable grid. Presently, the SD method is used to perform simulations of compressible flow past an oscillating circular cylinder. Oscillations parallel and normal to the free stream are considered at a fixed Reynolds number of 4000, oscillation frequency of 1 Hz , and oscillation amplitude of 20% cylinder diameter. We extend this study to large eddy simulations with the integration of a Smagorinsky-type subgrid-scale (SGS) model. Computational results will be compared to experimental data. The effectiveness of the large eddy simulation in capturing the vortex dynamics in the wake is analyzed. This work is funded by the Mechanical & Aerospace Engineering Department at George Washington University

  2. Multi-platform molecular profiling of a large cohort of glioblastomas reveals potential therapeutic strategies

    PubMed Central

    Xiu, Joanne; Piccioni, David; Juarez, Tiffany; Pingle, Sandeep C.; Hu, Jethro; Rudnick, Jeremy; Fink, Karen; Spetzler, David B.; Maney, Todd; Ghazalpour, Anatole; Bender, Ryan; Gatalica, Zoran; Reddy, Sandeep; Sanai, Nader; Idbaih, Ahmed; Glantz, Michael; Kesari, Santosh

    2016-01-01

    Glioblastomas (GBM) are the most aggressive and prevalent form of gliomas with abysmal prognosis and limited treatment options. We analyzed clinically relevant molecular aberrations suggestive of response to therapies in 1035 GBM tumors. Our analysis revealed mutations in 39 genes of 48 tested. IHC revealed expression of PD-L1 in 19% and PD-1 in 46%. MGMT-methylation was seen in 43%, EGFRvIII in 19% and 1p19q co-deletion in 2%. TP53 mutation was associated with concurrent mutations, while IDH1 mutation was associated with MGMT-methylation and TP53 mutation and was mutually exclusive of EGFRvIII mutation. Distinct biomarker profiles were seen in GBM compared with WHO grade III astrocytoma, suggesting different biology and potentially different treatment approaches. Analysis of 17 metachronous paired tumors showed frequent biomarker changes, including MGMT-methylation and EGFR aberrations, indicating the need for a re-biopsy for tumor profiling to direct subsequent therapy. MGMT-methylation, PR and TOPO1 appeared as significant prognostic markers in sub-cohorts of GBM defined by age. The current study represents the largest biomarker study on clinical GBM tumors using multiple technologies to detect gene mutation, amplification, protein expression and promoter methylation. These data will inform planning for future personalized biomarker-based clinical trials and identifying effective treatments based on tumor biomarkers. PMID:26933808

  3. Multi-platform molecular profiling of a large cohort of glioblastomas reveals potential therapeutic strategies.

    PubMed

    Xiu, Joanne; Piccioni, David; Juarez, Tiffany; Pingle, Sandeep C; Hu, Jethro; Rudnick, Jeremy; Fink, Karen; Spetzler, David B; Maney, Todd; Ghazalpour, Anatole; Bender, Ryan; Gatalica, Zoran; Reddy, Sandeep; Sanai, Nader; Idbaih, Ahmed; Glantz, Michael; Kesari, Santosh

    2016-04-19

    Glioblastomas (GBM) are the most aggressive and prevalent form of gliomas with abysmal prognosis and limited treatment options. We analyzed clinically relevant molecular aberrations suggestive of response to therapies in 1035 GBM tumors. Our analysis revealed mutations in 39 genes of 48 tested. IHC revealed expression of PD-L1 in 19% and PD-1 in 46%. MGMT-methylation was seen in 43%, EGFRvIII in 19% and 1p19q co-deletion in 2%. TP53 mutation was associated with concurrent mutations, while IDH1 mutation was associated with MGMT-methylation and TP53 mutation and was mutually exclusive of EGFRvIII mutation. Distinct biomarker profiles were seen in GBM compared with WHO grade III astrocytoma, suggesting different biology and potentially different treatment approaches. Analysis of 17 metachronous paired tumors showed frequent biomarker changes, including MGMT-methylation and EGFR aberrations, indicating the need for a re-biopsy for tumor profiling to direct subsequent therapy. MGMT-methylation, PR and TOPO1 appeared as significant prognostic markers in sub-cohorts of GBM defined by age. The current study represents the largest biomarker study on clinical GBM tumors using multiple technologies to detect gene mutation, amplification, protein expression and promoter methylation. These data will inform planning for future personalized biomarker-based clinical trials and identifying effective treatments based on tumor biomarkers. PMID:26933808

  4. Large differences in reanalyses of diabatic heating in the tropical upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Wright, J. S.; Fueglistaler, S.

    2013-09-01

    We present the time mean heat budgets of the tropical upper troposphere (UT) and lower stratosphere (LS) as simulated by five reanalysis models: the Modern-Era Retrospective Analysis for Research and Applications (MERRA), European Reanalysis (ERA-Interim), Climate Forecast System Reanalysis (CFSR), Japanese 25-yr Reanalysis and Japan Meteorological Agency Climate Data Assimilation System (JRA-25/JCDAS), and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis 1. The simulated diabatic heat budget in the tropical UTLS differs significantly from model to model, with substantial implications for representations of transport and mixing. Large differences are apparent both in the net heat budget and in all comparable individual components, including latent heating, heating due to radiative transfer, and heating due to parameterised vertical mixing. We describe and discuss the most pronounced differences. Discrepancies in latent heating reflect continuing difficulties in representing moist convection in models. Although these discrepancies may be expected, their magnitude is still disturbing. We pay particular attention to discrepancies in radiative heating (which may be surprising given the strength of observational constraints on temperature and tropospheric water vapour) and discrepancies in heating due to turbulent mixing (which have received comparatively little attention). The largest differences in radiative heating in the tropical UTLS are attributable to differences in cloud radiative heating, but important systematic differences are present even in the absence of clouds. Local maxima in heating and cooling due to parameterised turbulent mixing occur in the vicinity of the tropical tropopause.

  5. Analysis of Potential for Titanium Liner Buckling after Proof in a Large Kevlar/Epoxy COPV

    NASA Technical Reports Server (NTRS)

    Phoenix, S. Leigh; Kezirian, Michael T.

    2009-01-01

    We analyze the potential for liner buckling in a 40-in Kevlar49/epoxy overwrapped spherical pressure vessel (COPV) due to long, local depressions or valleys in the titanium liner, which appeared after proof testing (autofrettage). We begin by presenting the geometric characteristics of approximately 20 mil (0.02 in.) deep depressions measured by laser profilometry in several vessels. While such depths were more typical, depths of more than 40 mils (0.02 in.) were seen near the equator in one particular vessel. Such depressions are largely the result of overlap of the edges of overwrap bands (with rectangular cross-section prepreg tows) from the first or second wrap patterns particularly where they start and end. We then discuss the physical mechanisms of formation of the depressions during the autofrettage process in terms of uneven void compaction in the overwrap around the tow overlap lines and the resulting 10-fold increase in through-thickness stiffness of the overwrap. We consider the effects of liner plastic yielding mechanisms in the liner on residual bending moments and interface pressures with the overwrap both at the peak proof pressure (approx.6500 psi) and when reducing the pressure to 0 psi. During depressurization the Bauschinger phenomenon becomes very important whereby extensive yielding in tension reduces the magnitude of the yield threshold in compression by 30 to 40%, compared to the virgin annealed state of the liner titanium. In the absence of a depression, the liner is elastically stable in compression even at liner overwrap interface pressures nominally 6 times the approx. 1000 psi interface pressure that exists at 0 psi. Using a model based on a plate-on-an-elastic-foundation, we develop an extensive analysis of the possible destabilizing effects of a frozen-in valley. The analysis treats the modifying effects of the residual bending moments and interface pressures remaining after the proof hold as well as the Bauschinger effect on the

  6. Large differences in potential denitrification and sediment microbial communities across the Laurentian great lakes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lakes can be important sites for removal of reactive nitrogen (N) through denitrification, but spatial heterogeneity in denitrification rates can be high, and our understanding of factors controlling the capacity of lakes to remove excess N is incomplete. In oligotrophic Lake Superior, a century-lon...

  7. How to know and choose online games: differences between current and potential players.

    PubMed

    Teng, Ching-I; Lo, Shao-Kang; Wang, Pe-Cheng

    2007-12-01

    This study investigated how different adolescent players acquire game information and the criteria they use in choosing online games and found that (1) current players generally use comprehensive information sources more than potential players do; (2) current players rely on free trials and smooth display of motion graphics as choice criteria more than potential players do; (3) potential players rely on the look of advertisements more than current players do; (4) both current and potential players most likely use word-of-mouth and gaming programs on TV as information sources; and (5) endorser attractiveness is ranked the least important among six choice criteria by both current and potential players. PMID:18085974

  8. Effect of differently processed coffee on the gastric potential difference and intragastric pH in healthy volunteers.

    PubMed

    Ehrlich, A; Basse, H; Henkel-Ernst, J; Hey, B; Menthe, J; Lücker, P W

    1998-03-01

    The gastric irritation potential of orally administered coffee (150 ml) was investigated in four healthy volunteers by continuous measurement of gastric potential difference (GPD) and intragastric pH. Furthermore, serum gastrin concentrations were measured up to 45 min after administration of the coffee. One of the coffees, untreated, had to be compared with a pretreated coffee. The evaluation of the target parameters Reiz-Index, AUB, Pdmax and ttot revealed a significant difference between untreated coffee and specially treated coffee: the improved coffee processing produced significantly less mucosal irritation. Regarding the intragastric pH, no significant differences between the treatments were observed and no stimulation of gastric acid secretion following coffee was measurable. No consistent effect on serum gastrin concentration was seen: two of the four subjects had a steep increase in serum gastrin following administration with a clear difference between the differently processed coffees, whereas the other two subjects showed no change in serum gastrin. The results of this pilot study confirm the findings of former experiments on the reliability of continuous transmural GPD measurement when investigating the mucosal irritation potential of barrier breakers. PMID:9604858

  9. Large pi-aromatic molecules as potential sensitizers for highly efficient dye-sensitized solar cells.

    PubMed

    Imahori, Hiroshi; Umeyama, Tomokazu; Ito, Seigo

    2009-11-17

    Recently, dye-sensitized solar cells have attracted much attention relevant to global environmental issues. Thus far, ruthenium(II) bipyridyl complexes have proven to be the most efficient TiO(2) sensitizers in dye-sensitized solar cells. However, a gradual increment in the highest power conversion efficiency has been recognized in the past decade. More importantly, considering that ruthenium is a rare metal, novel dyes without metal or using inexpensive metal are desirable for highly efficient dye-sensitized solar cells. Large pi-aromatic molecules, such as porphyrins, phthalocyanines, and perylenes, are important classes of potential sensitizers for highly efficient dye-sensitized solar cells, owing to their photostability and high light-harvesting capabilities that can allow applications in thinner, low-cost dye-sensitized solar cells. Porphyrins possess an intense Soret band at 400 nm and moderate Q bands at 600 nm. Nevertheless, the poor light-harvesting properties relative to the ruthenium complexes have limited the cell performance of porphyrin-sensitized TiO(2) cells. Elongation of the pi conjugation and loss of symmetry in porphyrins cause broadening and a red shift of the absorption bands together with an increasing intensity of the Q bands relative to that of the Soret band. On the basis of the strategy, the cell performance of porphyrin-sensitized solar cells has been improved intensively by the enhanced light absorption. Actually, some push-pull-type porphyrins have disclosed a remarkably high power conversion efficiency (6-7%) that was close to that of the ruthenium complexes. Phthalocyanines exhibit strong absorption around 300 and 700 nm and redox features that are similar to porphyrins. Moreover, phthalocyanines are transparent over a large region of the visible spectrum, thereby enabling the possibility of using them as "photovoltaic windows". However, the cell performance was poor, owing to strong aggregation and lack of directionality in the

  10. Peculiarities of mantle lithosphere beneath the large kimberlite pipes in different regions for Siberian craton

    NASA Astrophysics Data System (ADS)

    Ashchepkov, Igor; Logvinova, Alla; Ntaflos, Theodoros; Vladykin, Nikolai; Spetsius, Zdislav; Kostrovitsky, Sergey; Stegnitsky, Yuri; Prokopyev, Sergey

    2016-04-01

    Comparison of the structure of the mantle columns and mineralogy of the large kimberlite pipes in Yakutia from the different regions, kimberlite fields and mantle terranes in Yakutia allowed several assumptions. 1. The large kimberlite pipes possibly trace the ancient magma feeders occurred in the time of the continent growth. Commonly kimberlites and large pipes are tracing the deep faults and lineaments tracing the ancient sutures, rift zones, trans -lithospheric faults and other permeable structures, which may be parallel to the ancient continental margins. Large pipes locate at the periodic distance like volcanoes in arc settings tracing the "volcanic fronts". 2. Large pipes commonly contain the higher amounts of the sub-calcic garnets representing the dunitic associations (Stachel et al., 2008). In ophiolites dunites veins are representing the channels for the melt transfer (Kelemen et al., 2002). It is likely that ancient large magmatic arc system could have also deep seated roots represented by the (sub calcic) garnet - bearing dunitic systems. 3. Many large pipes including Udachnaya (Pokhilenko et al., 1999) and Mir (Roden et al., 2006) contain in mantle roots high amount of various pyroxenites. The most ancient pyroxenites are supplementary to the dunitic associations. But mostly they represent the materials from the re-melted eclogites and partial and hybrid melts (plume and subduction -related). They are concentrating in the traps in the lithosphere base, in the middle part of mantle section and in the basaltic trap 2.0-3.0 GPa. Pyroxenites in the lithosphere base in some cases are vary abundant but mostly they are protokimberlitic cumulates from of the latest stages of plume activity. Products of the melts crystallization from the earlier stages represent easy melting material at the lithosphere base could be the traps for the later plume melts. 5. Large pipes as a rule reveal contrast layering which is favorite for the capturing of the material from

  11. Peculiarities of mantle lithosphere beneath the large kimberlite pipes in different regions for Siberian craton

    NASA Astrophysics Data System (ADS)

    Ashchepkov, Igor; Logvinova, Alla; Ntaflos, Theodoros; Vladykin, Nikolai; Spetsius, Zdislav; Kostrovitsky, Sergey; Stegnitsky, Yuri; Prokopyev, Sergey

    2016-04-01

    Comparison of the structure of the mantle columns and mineralogy of the large kimberlite pipes in Yakutia from the different regions, kimberlite fields and mantle terranes in Yakutia allowed several assumptions. 1. The large kimberlite pipes possibly trace the ancient magma feeders occurred in the time of the continent growth. Commonly kimberlites and large pipes are tracing the deep faults and lineaments tracing the ancient sutures, rift zones, trans -lithospheric faults and other permeable structures, which may be parallel to the ancient continental margins. Large pipes locate at the periodic distance like volcanoes in arc settings tracing the "volcanic fronts". 2. Large pipes commonly contain the higher amounts of the sub-calcic garnets representing the dunitic associations (Stachel et al., 2008). In ophiolites dunites veins are representing the channels for the melt transfer (Kelemen et al., 2002). It is likely that ancient large magmatic arc system could have also deep seated roots represented by the (sub calcic) garnet - bearing dunitic systems. 3. Many large pipes including Udachnaya (Pokhilenko et al., 1999) and Mir (Roden et al., 2006) contain in mantle roots high amount of various pyroxenites. The most ancient pyroxenites are supplementary to the dunitic associations. But mostly they represent the materials from the re-melted eclogites and partial and hybrid melts (plume and subduction -related). They are concentrating in the traps in the lithosphere base, in the middle part of mantle section and in the basaltic trap 2.0-3.0 GPa. Pyroxenites in the lithosphere base in some cases are vary abundant but mostly they are protokimberlitic cumulates from of the latest stages of plume activity. Products of the melts crystallization from the earlier stages represent easy melting material at the lithosphere base could be the traps for the later plume melts. 5. Large pipes as a rule reveal contrast layering which is favorite for the capturing of the material from

  12. Gender differences in schizotypic features in a large sample of young adults.

    PubMed

    Miller, L S; Burns, S A

    1995-10-01

    Research with self-report measures of schizotypic or psychosis-prone features in nonclinical populations suggests that, similarly to schizophrenic populations, males score higher on more "negative" schizotypic features and females score higher on more "positive" schizotypic features. We administered the Schizotypal Personality Questionnaire and the Chapman Scales of Psychosis Proneness--impulsivity/nonconformity, magical ideation, perceptual aberration, physical anhedonia, and social anhedonia--to a large, nonclinical, young adult sample (N = 1179: 453 males and 726 females). Results indicated increased negative symptomatology in males compared with females, but not increased positive symptomatology in females compared with males. Findings on Schizotypal Personality Questionnaire factors suggested that interpersonal deficits differed by gender as well. Finally, a measure of impulsive behavior and nonconformity not typically associated with negative symptomatology indicated gender differences not predicted by a negative/positive dichotomy. PMID:7561812

  13. Kinematical evidence for physically different classes of large-scale coronal EUV waves

    NASA Astrophysics Data System (ADS)

    Warmuth, A.; Mann, G.

    2011-08-01

    Context. Large-scale wavelike disturbances have been observed in the solar corona in the EUV range since more than a decade. The physical nature of these so-called "EIT waves" is still being debated controversially. The two main contenders are on the one hand MHD waves and/or shocks, and on the other hand magnetic reconfiguration in the framework of an expanding CME. There is a lot of observational evidence backing either one or the other scenario, and no single model has been able to reproduce all observational constraints, which are partly even contradictory. This suggests that there may actually exist different classes of coronal waves that are caused by distinct physical processes. Then, the problems in interpreting coronal waves would be mainly caused by mixing together different physical processes. Aims: We search for evidence for physically different classes of large-scale coronal EUV waves. Methods: Kinematics is the most important characteristic of any moving disturbance, hence we focus on this aspect of coronal waves. Identifying distinct event classes requires a large event sample, which is up to now only available from SOHO/EIT. We analyze the kinematics of a sample of 176 EIT waves. In order to check if the results are severely affected by the low cadence of EIT, we complement this with high-cadence data for 17 events from STEREO/EUVI. In particular, we focus on the wave speeds and their evolution. Results: Based on their kinematical behavior, we find evidence for three distinct populations of coronal EUV waves: initially fast waves (v ≥ 320 km s-1) that show pronounced deceleration (class 1 events), waves with moderate (v ≈ 170-320 km s-1) and nearly constant speeds (class 2), and slow waves (v ≤ 130 km s-1) showing a rather erratic behavior (class 3). Conclusions: The kinematical behavior of the fast decelerating disturbances is consistent with nonlinear large-amplitude waves or shocks that propagate faster than the ambient fast-mode speed and

  14. The ratios of partition functions at different temperatures - Sensitivity to potential energy shape II

    NASA Astrophysics Data System (ADS)

    Buchowiecki, Marcin

    2016-05-01

    The ratios of partition functions at different temperatures are calculated and its dependence on potential energy shape is analyzed. The role of anharmonicity and non-rigidity of rotations is discussed in the context of the angular frequency and the shape of potential energy curve. A role of inflection point of potential energy curve for the quality of rigid rotor harmonic oscillator and rigid rotor Morse oscillator is elucidated.

  15. Using river discharge to access the quality of different precipitation datasets over large-scale basins

    NASA Astrophysics Data System (ADS)

    Dutra, Emanuel; Balsamo, Gianpaolo; Wetterhall, Fredrik; Florian Pappenberger, ,; Yamazaki, Dai

    2015-04-01

    River discharge is a natural integrator of meteorological variables. The integration is made over a spatial domain (catchment) which is geophysically appropriate, and over time. It takes into account the correlations and covariances between several meteorological variables in a meaningful way, integrating information from a multidimensional variable space. Furthermore, river discharge observations are available and generally reliable. Therefore, river discharge is an important variable to consider in when evaluating the water balance of large-scale basins. In this study we evaluate different precipitation corrections applied to the ECMWF ERA-Interim reanalysis in terms of long-term means and variability of river discharge over several large-scale basins. We compare the original ERA-Interim dataset, the precipitation correction used in the production of the ERA-Interim/Land dataset (adjusted using GPCP) and the WFDEI dataset (adjusted using CRU). Global simulations with the ECMWF land surface model HTESSEL were performed with the different datasets and the simulated runoff routed using the river-floodplain model CaMa-Flood. Preliminary results highlight the deficiencies of ERA-Interim in several tropical basins (e.g. Congo) while the precipitation adjustments in ERA-Interim/Land and in WFDEI degrade the simulations in several northern hemisphere basins dominated by cold processes (e.g. Mackenzie).

  16. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    NASA Astrophysics Data System (ADS)

    Hao, Zhixin; Sun, Di

    2016-04-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after tropical volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport,therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  17. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    NASA Astrophysics Data System (ADS)

    Sun, D.; Hao, Z.; Zheng, J.

    2015-12-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after equatorial volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  18. The effect of photoelectrons on boom-satellite potential differences during electron beam ejection

    NASA Technical Reports Server (NTRS)

    Lai, Shu T.; Cohen, Herbert A.; Aggson, Thomas L.; Mcneil, William J.

    1987-01-01

    Data taken on the SCATHA satellite at geosynchronous altitudes during periods of electron beam ejection in sunlight showed that the potential difference between an electrically isolated boom and the satellite main body was a function of beam current, energy, and boom-sun angle. The potential difference decreased as the boom area illuminated by the sun increased; the maximum and minimum potential differences were measured when minimum and maximum boom areas, respectively, were exposed to the sun. It is shown that photoelectrons, created on the boom, could be engulfed in the electrostatic field of the highly charged satellite main body. Theoretical calculations made using a simple current balance model showed that these electrons could provide a substantial discharging current to the main body and cause the observed variations in the potential difference between the main body and the booms.

  19. Mountain birch - potentially large source of sesquiterpenes into high latitude atmosphere

    NASA Astrophysics Data System (ADS)

    Haapanala, S.; Ekberg, A.; Hakola, H.; Tarvainen, V.; Rinne, J.; Hellén, H.; Arneth, A.

    2009-11-01

    Emissions of volatile organic compounds (VOCs) from mountain birches were measured in Abisko, northern Sweden. Mountain birches make up the majority of the tree biomass in Scandinavian high latitudes, a region subject to significant climate warming. The measurements were carried out in two growing seasons. The emissions of four branches, each from a different individual tree, were measured in June-August 2006 and one of them again in July 2007. The measurements were conducted using a dynamic flow through chamber covered with Teflon film. The studied mountain birches were found to emit substantial amounts of linalool, monoterpenes and sesquiterpenes. The monoterpene emission was dominated by sabinene. The magnitude and composition of the sesquiterpene emission changed dramatically between the years. For example, the average α-farnesene emission potential in 2006 was almost 2600 ng gdw-1 h-1 (3.5 pmol gdw-1 s-1) while in 2007 α-farnesene was not detected at all. Also the emissions of other sesquiterpenes decreased in 2007 to a fraction of that in 2006. One possible explanation for the change in emissions is the herbivory damage that occurred in the area in 2004. Herbivory is known to enhance the emissions of sesquiterpenes, especially those of α-farnesene, and the effect may last for several years.

  20. Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen.

    PubMed

    Michaelis, Martin; Agha, Bishr; Rothweiler, Florian; Löschmann, Nadine; Voges, Yvonne; Mittelbronn, Michel; Starzetz, Tatjana; Harter, Patrick N; Abhari, Behnaz A; Fulda, Simone; Westermann, Frank; Riecken, Kristoffer; Spek, Silvia; Langer, Klaus; Wiese, Michael; Dirks, Wilhelm G; Zehner, Richard; Cinatl, Jaroslav; Wass, Mark N; Cinatl, Jindrich

    2015-01-01

    Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50 and IC90 values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells. PMID:25644037

  1. Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen

    PubMed Central

    Michaelis, Martin; Agha, Bishr; Rothweiler, Florian; Löschmann, Nadine; Voges, Yvonne; Mittelbronn, Michel; Starzetz, Tatjana; Harter, Patrick N.; Abhari, Behnaz A.; Fulda, Simone; Westermann, Frank; Riecken, Kristoffer; Spek, Silvia; Langer, Klaus; Wiese, Michael; Dirks, Wilhelm G.; Zehner, Richard; Cinatl, Jaroslav; Wass, Mark N.; Cinatl, Jindrich

    2015-01-01

    Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50 and IC90 values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells. PMID:25644037

  2. Using a High-Resolution Global Climate Model to Simulate Extratropical Cyclones with Large Storm Surge Potential

    NASA Astrophysics Data System (ADS)

    Alpert, A. J.; Broccoli, A. J.; Kapnick, S. B.

    2014-12-01

    The storm surge caused by Hurricane Sandy triggered a need for new research on surge inundation and associated risk. However, observational records of coastal water levels are limited, which increases uncertainty in risk analysis. Global climate models provide a means of simulating a much larger sample of potential surge-producing events, allowing for better resolution of the tail of the frequency distribution. The resolution of current climate models may be sufficient to simulate the structure and intensity of extratropical cyclones. Since 17 of the 20 greatest storm surge events at The Battery in New York City occurred in association with extratropical cyclones, we examine the ability of a coupled atmosphere-ocean general circulation model with 50 km atmospheric resolution (the GFDL CM2.5 model) to realistically simulate extratropical cyclones in the western North Atlantic Ocean that are capable of producing large storm surges. We analyze the similarities between CM2.5 and reanalysis products, including NASA's MERRA (Modern-Era Retrospective analysis for Research and Applications). After considering differences in spatial and temporal resolution, preliminary analyses suggest that indicators of cyclone strength in CM2.5 and MERRA are comparable. We also investigate a simple screening method based on wind speed and direction to identify potential surge-producing events in CM2.5 for determining a subset of events for more detailed analysis.

  3. Large submarine earthquakes occurred worldwide, 1 year period (June 2013 to June 2014), - contribution to the understanding of tsunamigenic potential

    NASA Astrophysics Data System (ADS)

    Omira, R.; Vales, D.; Marreiros, C.; Carrilho, F.

    2015-03-01

    This paper is a contribution to a better understanding of tsunamigenic potential from large submarine earthquakes. Here, we analyse the tsunamigenic potential of large earthquakes occurred worldwide with magnitudes around Mw 7.0 and greater, during a period of 1 year, from June 2013 to June 2014. The analysis involves earthquake model evaluation, tsunami numerical modelling, and sensors' records analysis in order to confirm the generation or not of a tsunami following the occurrence of an earthquake. We also investigate and discuss the sensitivity of tsunami generation to the earthquake parameters recognized to control the tsunami occurrence, including the earthquake magnitude, focal mechanism and fault rupture depth. A total of 23 events, with magnitudes ranging from Mw 6.7 to Mw 8.1 and hypocenter depths varying from 10 up to 585 km, have been analyzed in this study. Among them, 52% are thrust faults, 35% are strike-slip faults, and 13% are normal faults. Most analyzed events have been occurred in the Pacific Ocean. This study shows that about 39% of the analyzed earthquakes caused tsunamis that were recorded by different sensors with wave amplitudes varying from few centimetres to about 2 m. Some of them caused inundations of low-lying coastal areas and significant damages in harbours. On the other hand, tsunami numerical modeling shows that some of the events, considered as non-tsunamigenic, might trigger small tsunamis that were not recorded due to the absence of sensors in the near-field areas. We also find that the tsunami generation is mainly dependent of the earthquake focal mechanism and other parameters such as the earthquake hypocenter depth and the magnitude. The results of this study can help on the compilation of tsunami catalogs.

  4. How does the foraging behavior of large herbivores cause different associational plant defenses?

    PubMed Central

    Huang, Yue; Wang, Ling; Wang, Deli; Zeng, De-Hui; Liu, Chen

    2016-01-01

    The attractant-decoy hypothesis predicts that focal plants can defend against herbivory by neighboring with preferred plant species when herbivores make decisions at the plant species scale. The repellent-plant hypothesis assumes that focal plants will gain protection by associating with nonpreferred neighbors when herbivores are selective at the patch scale. However, herbivores usually make foraging decisions at these scales simultaneously. The net outcomes of the focal plant vulnerability could depend on the spatial scale at which the magnitude of selectivity by the herbivores is stronger. We quantified and compared the within- and between-patch overall selectivity index (OSI) of sheep to examine the relationships between associational plant effects and herbivore foraging selectivity. We found that the sheep OSI was stronger at the within- than the between-patch scale, but focal plant vulnerability followed both hypotheses. Focal plants defended herbivory with preferred neighbors when the OSI difference between the two scales was large. Focal plants gained protection with nonpreferred neighbors when the OSI difference was narrowed. Therefore, the difference in selectivity by the herbivores between the relevant scales results in different associational plant defenses. Our study suggests important implications for understanding plant-herbivore interactions and grassland management. PMID:26847834

  5. The Repopulation Potential of Hepatocyte Populations Differing in Size and Prior Mitotic Expansion

    PubMed Central

    Overturf, Ken; Al-Dhalimy, Muhsen; Finegold, Milton; Grompe, Markus

    1999-01-01

    Recently the stem cell-like regenerative potential of adult liver cells was demonstrated by serial transplantation. This repopulation capacity could be useful for the treatment of genetic liver diseases by cell transplantation and/or expansion of genetically manipulated cells. However, previous experiments used unfractionated populations of liver cells, and therefore it remained undetermined whether all hepatocytes or only a subpopulation (stem cells) possessed this high regenerative ability. To address this question we used centrifugal elutriation to separate hepatocytes by cell density. Unexpectedly, small hepatocytes (16 μm) had lower repopulation capacity during the first round of transplantation when compared with both the medium-sized (21 μm) and large (27 μm) cells. We also compared the repopulation capacity of hepatocytes that had undergone different degrees of in vivo expansion. Previous cell division neither reduced nor increased the repopulation capacity of transplanted liver cells. Finally, retroviral tagging experiments demonstrated that liver-repopulating cells occur at a frequency of >1:10,000. We conclude that short-term therapeutic liver repopulation does not require progenitor or stem cells. PMID:10595942

  6. Potential temperature, upwelling rate and eclogite in the formation of the North Atlantic large igneous province

    NASA Astrophysics Data System (ADS)

    Brown, E. L.; Lesher, C. E.

    2010-12-01

    The volumes and compositions of basalts generated by adiabatic decompression melting of the Earth’s mantle depend on mantle potential temperature (T_P), upwelling rate and the fertility of the mantle source. The relative importance of these factors in generating the high productivity magmatism of the Paleogene - Recent North Atlantic large igneous province (NAIP) remains controversial. Each has been proposed as a primary factor in the region. To assess the significance of these mechanisms in NAIP magmatism, we apply our forward melting model, REEBOX PRO, which simulates the melting of a heterogeneous source comprised of peridotite and eclogite lithologies. The model accounts for the thermodynamics of adiabatic decompression melting of a heterogeneous source using constraints from laboratory melting experiments. Input values of T_P and eclogite abundance are used to calculate the buoyancy of the mantle source and maximum upwelling rates. Source buoyancy constrains the maximum amount of eclogite in the mantle source that can ascend beneath the rift axis. All melts generated within the melting regime are pooled to form magmatic crust according to the residual column method. Using the model, variations in magmatic crustal thickness (from geophysics) as a function of eclogite content (from geochemistry) can be related to T_P and upwelling rate. Models with no thermal anomaly, that call on either enhanced upwelling rates due to plate separation (edge - driven convection) or the melting of abundant (> 30%) eclogite at “ambient” T_P (1325 °C), cannot generate the observed igneous crustal thicknesses around the province. Rather, elevated mantle T_P (minimum thermal anomaly ~ 85 - 195 °C) and associated buoyancy - driven upwelling are needed to explain the volume of igneous crust in the province. Involvement of eclogite, while necessary to explain the compositions of many NAIP lavas, does not significantly enhance melt production. These factors, coupled with the long

  7. Sex Differences on "g" and Non-"g" Intellectual Performance Reveal Potential Sources of STEM Discrepancies

    ERIC Educational Resources Information Center

    Lemos, Gina C.; Abad, Francisco J.; Almeida, Leandro S.; Colom, Roberto

    2013-01-01

    The analysis of sex differences in cognitive abilities is largely confusing because these differences are masked by the pervasive influence of the general factor of intelligence (g). In this study a battery of five reasoning tests (abstract [AR], numerical [NR], verbal [VR], mechanical [MR], and spatial [SR]) was completed by a sample of 3233…

  8. Large differences in land use emission quantifications implied by definition discrepancies

    NASA Astrophysics Data System (ADS)

    Stocker, B. D.; Joos, F.

    2015-03-01

    The quantification of CO2 emissions from anthropogenic land use and land use change (eLUC) is essential to understand the drivers of the atmospheric CO2 increase and to inform climate change mitigation policy. Reported values in synthesis reports are commonly derived from different approaches (observation-driven bookkeeping and process-modelling) but recent work has emphasized that inconsistencies between methods may imply substantial differences in eLUC estimates. However, a consistent quantification is lacking and no concise modelling protocol for the separation of primary and secondary components of eLUC has been established. Here, we review the conceptual differences of eLUC quantification methods and apply an Earth System Model to demonstrate that what is claimed to represent total eLUC differs by up to ~20% when quantified from ESM vs. offline vegetation models. Under a future business-as-usual scenario, differences tend to increase further due to slowing land conversion rates and an increasing impact of altered environmental conditions on land-atmosphere fluxes. We establish how coupled Earth System Models may be applied to separate component fluxes of eLUC arising from the replacement of potential C sinks/sources and the land use feedback and show that secondary fluxes derived from offline vegetation models are conceptually and quantitatively not identical to either, nor their sum. Therefore, we argue that synthesis studies and global carbon budget accountings should resort to the "least common denominator" of different methods, following the bookkeeping approach where only primary land use emissions are quantified under the assumption of constant environmental boundary conditions.

  9. Comparison of different hand-drying methods: the potential for airborne microbe dispersal and contamination.

    PubMed

    Best, E L; Redway, K

    2015-03-01

    Efficient washing and drying of hands is important in prevention of the transfer of micro-organisms. However, knowledge surrounding the potential for microbial contamination according to hand-drying methods is limited. This study assessed the potential for airborne microbe dispersal during hand drying by four methods (paper towels, roller towel, warm air and jet air dryer) using three different models. The jet air dryer dispersed liquid from users' hands further and over a greater range (up to 1.5m) than the other drying methods (up to 0.75 m), demonstrating the differing potential risks for airborne microbe dissemination, particularly if handwashing is suboptimal. PMID:25586988

  10. Sex differences in the risk of receiving potentially inappropriate prescriptions among older adults

    PubMed Central

    Morgan, Steven G.; Weymann, Deirdre; Pratt, Brandy; Smolina, Kate; Gladstone, Emilie J.; Raymond, Colette; Mintzes, Barbara

    2016-01-01

    Objectives: to measure sex differences in the risk of receiving potentially inappropriate prescription drugs and to examine what are the factors that contribute to these differences. Design: a retrospective cohort study. Setting: community setting of British Columbia, Canada. Participants: residents of British Columbia aged 65 and older (n = 660,679). Measurements: we measured 2013 period prevalence of prescription dispensations satisfying the American Geriatrics Society's 2012 version of the Beers Criteria for potentially inappropriate medication use in older adults. We used logistic regressions to test for associations between this outcome and a number of clinical and socioeconomic factors. Results: a larger share of women (31%) than of men (26%) filled one or more potentially inappropriate prescription in the community. The odds of receiving potentially inappropriate prescriptions are associated with several clinical and socioeconomic factors. After controlling for those factors, community-dwelling women were at 16% higher odds of receiving a potentially inappropriate prescription than men (adjusted odds ratio = 1.16, 95% confidence interval = 1.12–1.21). Much of this sex difference stemmed from women's increased odds of receiving potentially inappropriate prescriptions for benzodiazepines and other hypnotics, for tertiary tricyclic antidepressants and for non-selective NSAIDs. Conclusion: there are significant sex differences in older adults' risk of receiving a potentially inappropriate prescription as a result of complex intersections between gender and other social constructs. Appropriate responses will therefore require changes in the information, norms and expectations of both prescribers and patients. PMID:27151390

  11. Large Differences in Aging Phenotype between Strains of the Short-Lived Annual Fish Nothobranchius furzeri

    PubMed Central

    Benedetti, Mauro; Roncaglia, Paola; Cattaneo, Antonino; Domenici, Luciano; Cellerino, Alessandro

    2008-01-01

    Background A laboratory inbred strain of the annual fish Nothobranchius furzeri shows exceptionally short life expectancy and accelerated expression of age markers. In this study, we analyze new wild-derived lines of this short-lived species. Methodology/Principal Findings We characterized captive survival and age-related traits in F1 and F2 offspring of wild-caught N. furzeri. Wild-derived N. furzeri lines showed expression of lipofuscin and neurodegeneration at age 21 weeks. Median lifespan in the laboratory varied from to 20 to 23 weeks and maximum lifespan from 25 to 32 weeks. These data demonstrate that rapid age-dependent decline and short lifespan are natural characteristics of this species. The N. furzeri distribution range overlaps with gradients in altitude and aridity. Fish from more arid habitats are expected to experience a shorter survival window in the wild. We tested whether captive lines stemming from semi-arid and sub-humid habitats differ in longevity and expression of age-related traits. We detected a clear difference in age-dependent cognitive decline and a slight difference in lifespan (16% for median, 15% for maximum lifespan) between these lines. Finally, we observed shorter lifespan and accelerated expression of age-related markers in the inbred laboratory strain compared to these wild-derived lines. Conclusions/Significance Owing to large differences in aging phenotypes in different lines, N. furzeri could represent a model system for studying the genetic control of life-history traits in natural populations. PMID:19052641

  12. Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database

    SciTech Connect

    Uehara, Takeki; Minowa, Yohsuke; Morikawa, Yuji; Kondo, Chiaki; Maruyama, Toshiyuki; Kato, Ikuo; Nakatsu, Noriyuki; Igarashi, Yoshinobu; Ono, Atsushi; Hayashi, Hitomi; Mitsumori, Kunitoshi; Yamada, Hiroshi; Ohno, Yasuo; Urushidani, Tetsuro

    2011-09-15

    The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The negative training set consisted of high- or middle-dose groups of 54 non-carcinogens. Support vector machine combined with wrapper-type gene selection algorithms was used for modeling. Consequently, our best classifier yielded prediction accuracies for hepatocarcinogenicity of 99% sensitivity and 97% specificity in the training data set, and false positive prediction was almost completely eliminated. Pathway analysis of feature genes revealed that the mitogen-activated protein kinase p38- and phosphatidylinositol-3-kinase-centered interactome and the v-myc myelocytomatosis viral oncogene homolog-centered interactome were the 2 most significant networks. The usefulness and robustness of our predictor were further confirmed in an independent validation data set obtained from the public database. Interestingly, similar positive predictions were obtained in several genotoxic hepatocarcinogens as well as non-genotoxic hepatocarcinogens. These results indicate that the expression profiles of our newly selected candidate biomarker genes might be common characteristics in the early stage of carcinogenesis for both genotoxic and non-genotoxic carcinogens in the rat liver. Our toxicogenomic model might be useful for the prospective screening of hepatocarcinogenicity of compounds and prioritization of compounds for carcinogenicity testing. - Highlights: >We developed a toxicogenomic model to predict hepatocarcinogenicity of chemicals. >The optimized model consisting of 9 probes had 99% sensitivity and 97% specificity. >This model

  13. Evoked potentials in large-scale cortical networks elicited by TMS of the visual cortex

    PubMed Central

    Grossman, Emily D.; Srinivasan, Ramesh

    2011-01-01

    Single pulses of transcranial magnetic stimulation (TMS) result in distal and long-lasting oscillations, a finding directly challenging the virtual lesion hypothesis. Previous research supporting this finding has primarily come from stimulation of the motor cortex. We have used single-pulse TMS with simultaneous EEG to target seven brain regions, six of which belong to the visual system [left and right primary visual area V1, motion-sensitive human middle temporal cortex, and a ventral temporal region], as determined with functional MRI-guided neuronavigation, and a vertex “control” site to measure the network effects of the TMS pulse. We found the TMS-evoked potential (TMS-EP) over visual cortex consists mostly of site-dependent theta- and alphaband oscillations. These site-dependent oscillations extended beyond the stimulation site to functionally connected cortical regions and correspond to time windows where the EEG responses maximally diverge (40, 200, and 385 ms). Correlations revealed two site-independent oscillations ∼350 ms after the TMS pulse: a theta-band oscillation carried by the frontal cortex, and an alpha-band oscillation over parietal and frontal cortical regions. A manipulation of stimulation intensity at one stimulation site (right hemisphere V1-V3) revealed sensitivity to the stimulation intensity at different regions of cortex, evidence of intensity tuning in regions distal to the site of stimulation. Together these results suggest that a TMS pulse applied to the visual cortex has a complex effect on brain function, engaging multiple brain networks functionally connected to the visual system with both invariant and site-specific spatiotemporal dynamics. With this characterization of TMS, we propose an alternative to the virtual lesion hypothesis. Rather than a technique that simulates lesions, we propose TMS generates natural brain signals and engages functional networks. PMID:21715670

  14. Large-scale plasma transport in the magnetotail during different solar wind conditions

    NASA Astrophysics Data System (ADS)

    Myllys, Minna; Kilpua, Emilia; Pulkkinen, Tuija

    2015-04-01

    We present results from a study on how solar wind conditions affect the energy and plasma transport in the geomagnetic tail and how they modify the large-scale magnetotail configuration. We study the large-scale plasma transport in the magnetotail using tail observations from the five THEMIS spacecrafts during 2008-2011. During this period the THEMIS spacecraft spent a considerable time in the geomagnetic tail allowing us to compile statistical maps of plasma flow and energy transport properties. Furthermore, this time period corresponds to the extended and prolonged solar activity minimum between solar cycle 23 and 24 and relatively quiet rising phase of cycle 24. This allowed us to investigate magnetospheric processes and solar wind-magnetospheric coupling during relatively quiet state of the magnetosphere. In order to separate the role of different solar wind parameters and their activity level on the average sunward and tailward plasma flows and the occurrence rate of fast plasma bursts, the magnetospheric data was binned according to solar wind speed, dynamic pressure and IMF measurements. Our results show that the tailward flow bursts are not dependent on the solar wind conditions, but that the sign of the IMF z-component (GSM coordinates) causes the most visible effect to the occurence rate and pattern of sunward flows.

  15. Large Deformation Mechanisms, Plasticity, and Failure of an Individual Collagen Fibril With Different Mineral Content.

    PubMed

    Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J; Buehler, Markus J

    2016-02-01

    Mineralized collagen fibrils are composed of tropocollagen molecules and mineral crystals derived from hydroxyapatite to form a composite material that combines optimal properties of both constituents and exhibits incredible strength and toughness. Their complex hierarchical structure allows collagen fibrils to sustain large deformation without breaking. In this study, we report a mesoscale model of a single mineralized collagen fibril using a bottom-up approach. By conserving the three-dimensional structure and the entanglement of the molecules, we were able to construct finite-size fibril models that allowed us to explore the deformation mechanisms which govern their mechanical behavior under large deformation. We investigated the tensile behavior of a single collagen fibril with various intrafibrillar mineral content and found that a mineralized collagen fibril can present up to five different deformation mechanisms to dissipate energy. These mechanisms include molecular uncoiling, molecular stretching, mineral/collagen sliding, molecular slippage, and crystal dissociation. By multiplying its sources of energy dissipation and deformation mechanisms, a collagen fibril can reach impressive strength and toughness. Adding mineral into the collagen fibril can increase its strength up to 10 times and its toughness up to 35 times. Combining crosslinks with mineral makes the fibril stiffer but more brittle. We also found that a mineralized fibril reaches its maximum toughness to density and strength to density ratios for a mineral density of around 30%. This result, in good agreement with experimental observations, attests that bone tissue is optimized mechanically to remain lightweight but maintain strength and toughness. PMID:26866939

  16. Large differences in catch per unit of effort between two minnow trap models

    PubMed Central

    2013-01-01

    Background Little is known about variation in catch per unit of effort (CPUE) in stickleback fisheries, or the factors explaining this variation. We investigated how nine-spined stickleback (Pungitius pungitius) CPUE was influenced by trap model by comparing the CPUEs of two very similar minnow trap models fished side-by-side in a paired experimental design. Results The galvanized trap type (mean CPUE = 1.31 fish h–1) out-fished the black trap type (mean CPUE = 0.20 fish h–1) consistently, and yielded on average 81% more fish. Conclusions The results demonstrate that small differences in trap appearance can have large impacts on CPUE. This has implications for studies designed to investigate abundance and occurrence of fish using minnow traps. PMID:23590839

  17. Gender Differences in Memory Processing: Evidence from Event-Related Potentials to Faces

    ERIC Educational Resources Information Center

    Guillem, F.; Mograss, M.

    2005-01-01

    This study investigated gender differences on memory processing using event-related potentials (ERPs). Behavioral data and ERPs were recorded in 16 males and 10 females during a recognition memory task for faces. The behavioral data results showed that females performed better than males. Gender differences on ERPs were evidenced over anterior…

  18. Location, location, location: small shifts in collection site result in large intraspecific differences in macroalgal palatability

    NASA Astrophysics Data System (ADS)

    Keeley, Kathryn N.; Stroh, Jolie D.; Tran, Diem Samantha C.; Fong, Caitlin R.; Fong, Peggy

    2015-06-01

    The role of herbivorous fishes in coral reef resilience has increased interest in the process of herbivory and has focused attention on herbivore feeding behavior, making it important to evaluate experimental methods used to assess herbivore decisions. We tested whether small-scale differences in collection site play a role in within-species palatability of macroalgae. Baseline grazing assays using algae collected on a fringing reef in Moorea, French Polynesia, revealed that herbivore preferences among three common species ranked Padina boryana > Sargassum mangarevense ≫ Amansia rhodantha. Comparing grazing preferences between individual thalli of the same species collected <15 m apart revealed that consumption of intertidal S. mangarevense was nearly six times greater than for conspecifics collected from the adjacent subtidal reef flat. The same trend occurred for P. boryana but was not significant. This demonstrated that algal palatability can vary on a very small spatial scale, presenting a potential trap for the unwary when setting up experiments; we encourage researchers to consider this potential complication in experimental studies of herbivory.

  19. Structure of different within-plate magmatic system of large igneous provinces

    NASA Astrophysics Data System (ADS)

    Sharkov, E.

    2009-04-01

    It is generally accepted that formation of continental large igneous provinces (LIPs) is linked with ascending of mantle superplumes. However, it is not clear yet why and how magmatic systems appeared and functionated. It is known that LIPs are formed by numerous magmatic centers, which imply existence of individual magmatic systems beneath them. Such a situation can be explained by presence of protuberances (local plumes) on the surface of extended superplume heads, where processes of adiabatic melting occurred give rise to formation of magmatic systems. Newly-formed melts on their way to the surface pass through complicate system of conduits and transitional magma chambers, where they were undergone by different processes of crystallizing differentiation, mixing, assimilation of wall-rocks, etc. According to data available, three major levels of transitional magmatic chambers, linked by systems of feeder conduits (dikes), occurred within the crust. Each of them is responsible for transformation of a primary melt in different extent: The lowest level with the largest chambers, located along boundary between upper margin of the plume head and incumbent rigid lithosphere; they are responsible for the underplating phenomenon. Processes of contamination mantle-derived magmas by crustal material can play essential role here, especially in the late Archean and early Paleoproterozoic when they led to appearance of specific mantle-crustal magmas of siliceous high-Mg series (SHMS), which formed large igneous provinces with numerous mafic-iltramafic layered intrusions (Sharkov, Bogina, 2006). It suggests that formation of this series was linked with "floating up" of chambers (batches) of high-temperature ultramafic magmas through the upper part of lithospheric mantle and mafic lower crust by zone refinement mechanism, i.e. by melting material of the chamber's roof and crystallization at their bottoms. As a result, the primary melt gradually enriched in crustal material

  20. Leveraging a large scale mammalian pharmacological dataset to prioritize potential environmental hazard of pharmaceuticals

    EPA Science Inventory

    The potential for pharmaceuticals in the environment to cause adverse ecological effects is of increasing concern. Given the thousands of active pharmaceutical ingredients (APIs) which can enter the aquatic environment through various means, a current challenge in aquatic toxicol...

  1. Potential of mean force of association of large hydrophobic particles: toward the nanoscale limit.

    PubMed

    Makowski, Mariusz; Czaplewski, Cezary; Liwo, Adam; Scheraga, Harold A

    2010-01-21

    The potentials of mean force (PMFs) were determined, in both water with the TIP3P water model and in vacuo, for systems involving formation of nonpolar dimers composed of bicyclooctane, adamantane (both an all-atom model and a sphere with the radius of 3.4 A representing adamantane), and fullerene, respectively. A series of umbrella-sampling molecular dynamics simulations with the AMBER force field were carried out for each pair under both environmental conditions. The PMFs were calculated by using the weighted histogram analysis method. The results were compared with our previously determined PMF for neopentane. The shape of the PMFs for dimers of all four nonpolar molecules is characteristic of hydrophobic interactions with contact and solvent-separated minima and desolvation maxima. The positions of all these minima and maxima change with the size of the nonpolar molecule; for larger molecules they shift toward larger distances. Comparison of the PMFs of the bicyclooctane, adamantane, and fullerene dimers in water and in vacuo shows that hydrophobic interactions in each dimer are different from that for the dimer of neopentane. Interactions in the bicyclooctane, adamantane, and fullerene dimers are stronger in vacuo than in water. These dimers cannot be treated as classical, spherical, hydrophobic objects. The solvent contribution to the PMF was also computed by subtracting the PMF determined in vacuo from that in explicit solvent. The solvent contribution to the PMFs of bicyclooctane, adamantane, and fullerene is positive, as opposed to that of neopentane. The water molecules in the first solvation sphere of both adamantane and neopentane dimers are more ordered as compared to bulk water, with their dipole moments pointing away from the surface of the dimers. The average number of hydrogen bonds per water molecule in the first hydration shell of adamantane is smaller compared to that in bulk water, but this shell is thicker for all-atom adamantane than for

  2. Simulation of a Supercritical Fluid Flow with Large Temperature Difference under the Assumption of Constant Pressure

    NASA Astrophysics Data System (ADS)

    Komurasaki, Satoko

    2015-11-01

    Eruption of geothermally heated water from the hydrothermal vent in deep oceans of depth over 2,000 meters is numerically simulated. The hydrostatic pressure of water is assumed to be over 200 atmospheres, and the temperature of heated water is occasionally more than 300°C. Under these conditions, a part of heated water can be in the supercritical state, and the physical properties can change significantly by the temperature. Particularly, thermal diffusivity at the critical temperature becomes so small, which prevents heat diffusion, and the temperature gradients can become high. Simulation of this kind of fluid flow can be carried out only by using a highly robust scheme. In this paper, a scheme for a highly-unsteady-flow computation is introduced, and a supercritical fluid flow with a large temperature difference is simulated at a constant pressure. In the computation, the compressible Navier-Stokes equations are solved using a method for the incompressible equations under constant pressure. The equations are approximated by the multidirectional finite difference method and KK scheme is used to stabilize the high-accuracy computation. This work was partially supported by Grant-in-Aid for Scientific Research from MEXT/JSPS (26610119).

  3. Differences in ichthyofauna feeding habits among lateral lagoons and the river channel in a large reservoir.

    PubMed

    Ferrareze, M; Nogueira, M G; Casatti, L

    2015-05-01

    In this study, we investigated differences in feeding habits of small-sized ichthyofauna among lateral lagoons and the river channel in a large reservoir. The study was performed in four lagoons and in one sampling site of the main channel in Rosana Reservoir, Paranapanema River, Brazil. The samples were taken in September and November of 2004 and in January, March, May, and August of 2005. Fish were sampled with a 7.5 m2 hand net. Five manual throws were made toward aquatic macrophytes stands. The sampling design favored the collection of small-sized fish fauna (juveniles/small-sized species). The stomach contents of 42 species were analyzed. A total of 183 different items were consumed by fish. These items were grouped in 11 food categories, which were used to classify fish into seven trophic guilds. Aquatic insects were consumed by 32 species and were the predominant feeding item. In the river, the most consumed items were aquatic insects, cladocerans, and phytoplankton, whereas in the lagoons aquatic insects, copepods, and cladocerans were the main items. By comparing each trophic guild, the number of insectivores, algivores, and zooplanktivores species was higher in the lagoons than in the river, and the opposite was found only for omnivore fish. Low niche width in all sites indicates high trophic specialization and low niche overlap between pairs of species. Fish assemblage in the lateral lagoons presents feeding habits distinct from those of the river species, indicating that the coexistence and high abundance of small-sized fish in the sampling sites are explained by their high feeding adaptability, which includes a tendency toward dietary specialization, low feeding overlap, and resource partitioning, along with different temporal resource uses. PMID:26132022

  4. On the energy integral formulation of gravitational potential differences from satellite-to-satellite tracking

    NASA Astrophysics Data System (ADS)

    Guo, J. Y.; Shang, K.; Jekeli, C.; Shum, C. K.

    2015-04-01

    Two approaches have been formulated to compute the gravitational potential difference using low-low satellite-to-satellite tracking data based on energy integral: one in the geocentric inertial reference system, and the other in the terrestrial reference system. The focus of this work is on the approach in the geocentric inertial reference system, where a potential rotation term appears in addition to the potential term. In former formulations, the contribution of the time-variable components of the gravitational potential to the potential term was included, but their contribution to the potential rotation term was neglected. In this work, an improvement to the former formulations is made by reformulating the potential rotation term to include the contribution of the time-variable components of the gravitational potential. A simulation shows that our more accurate formulation of the potential rotation term is necessary to achieve the accuracy for recovering the temporal variation of the Earth's gravity field, such as for use to the Gravity Recovery And Climate Experiment GRACE observation data based on this approach.

  5. Differences between the deformed-potential and folding-model descriptions of inelastic nuclear scattering

    SciTech Connect

    Hnizdo, V. )

    1994-08-01

    The differences between the deformed-potential and folding-model descriptions of inelastic nuclear scattering, attention to which has been called recently by Beene, Horen, and Satchler [Phys. Rev. C 48, 3128 (1993)], were pointed out already some time ago by contrasting the rules of equal deformation lengths and equal normalized multipole moments for the optical potential and the underlying nucleon distribution of the excited nucleus.

  6. Tree Species Linked to Large Differences in Ecosystem Carbon Distribution in the Boreal Forest of Alaska

    NASA Astrophysics Data System (ADS)

    Melvin, A. M.; Mack, M. C.; Johnstone, J. F.; Schuur, E. A. G.; Genet, H.; McGuire, A. D.

    2014-12-01

    In the boreal forest of Alaska, increased fire severity associated with climate change is altering plant-soil-microbial feedbacks and ecosystem carbon (C) dynamics. The boreal landscape has historically been dominated by black spruce (Picea mariana), a tree species associated with slow C turnover and large soil organic matter (SOM) accumulation. Historically, low severity fires have led to black spruce regeneration post-fire, thereby maintaining slow C cycling rates and large SOM pools. In recent decades however, an increase in high severity fires has led to greater consumption of the soil organic layer (SOL) during fire and subsequent establishment of deciduous tree species in areas previously dominated by black spruce. This shift to a more deciduous dominated landscape has many implications for ecosystem structure and function, as well as feedbacks to global C cycling. To improve our understanding of how boreal tree species affect C cycling, we quantified above- and belowground C stocks and fluxes in adjacent, mid-successional stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a 1958 fire near Fairbanks, Alaska. Although total ecosystem C pools (aboveground live tree biomass + dead wood + SOL + top 10 cm of mineral soil) were similar for the two stand types, the distribution of C among pools was markedly different. In black spruce, 78% of measured C was found in soil pools, primarily in the SOL, where spruce contained twice the C stored in paper birch (4.8 ± 0.3 vs. 2.4 ± 0.1 kg C m-2). In contrast, aboveground biomass dominated ecosystem C pools in birch forest (6.0 ± 0.3 vs. 2.5 ± 0.2 kg C m-2 in birch and spruce, respectively). Our findings suggest that tree species exert a strong influence over plant-soil-microbial feedbacks and may have long-term effects on ecosystem C sequestration and storage that feedback to the climate system.

  7. Large Deformation Mechanisms, Plasticity, and Failure of an Individual Collagen Fibril With Different Mineral Content

    PubMed Central

    Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J

    2016-01-01

    ABSTRACT Mineralized collagen fibrils are composed of tropocollagen molecules and mineral crystals derived from hydroxyapatite to form a composite material that combines optimal properties of both constituents and exhibits incredible strength and toughness. Their complex hierarchical structure allows collagen fibrils to sustain large deformation without breaking. In this study, we report a mesoscale model of a single mineralized collagen fibril using a bottom‐up approach. By conserving the three‐dimensional structure and the entanglement of the molecules, we were able to construct finite‐size fibril models that allowed us to explore the deformation mechanisms which govern their mechanical behavior under large deformation. We investigated the tensile behavior of a single collagen fibril with various intrafibrillar mineral content and found that a mineralized collagen fibril can present up to five different deformation mechanisms to dissipate energy. These mechanisms include molecular uncoiling, molecular stretching, mineral/collagen sliding, molecular slippage, and crystal dissociation. By multiplying its sources of energy dissipation and deformation mechanisms, a collagen fibril can reach impressive strength and toughness. Adding mineral into the collagen fibril can increase its strength up to 10 times and its toughness up to 35 times. Combining crosslinks with mineral makes the fibril stiffer but more brittle. We also found that a mineralized fibril reaches its maximum toughness to density and strength to density ratios for a mineral density of around 30%. This result, in good agreement with experimental observations, attests that bone tissue is optimized mechanically to remain lightweight but maintain strength and toughness. © 2015 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR). PMID:26866939

  8. Quantitative assessment of normal and potentially premalignant epithelium at different levels of human colorectal crypts.

    PubMed

    Tipoe, G L; White, F H

    1998-04-01

    The present study uses morphometric techniques to assess whether altered differentiation patterns exist in PPM which might reflect its premalignant status. Samples were obtained from resected malignant lesions of large bowels of 10 Chinese patients. Normal (N) samples were biopsied from the margins of each resected large bowel. Potentially premalignant (PPM) mucosae were obtained from within 2 cm of the margins of the malignant lesions. Tissues were processed for histological examination and using strict criteria, colorectal crypts were divided into basal (B), intermediate (I) and surface (S) segments. Interactive digitisation of sections from each group was used to generate the following morphometric parameters in each segment: nuclear profile circularity indices (NSF and NCI); nuclear numerical density (NA and NV); the degree of deviation of the major nuclear axis in relation to the epithelial-connective junction (AGDMAX); cell height (CH); the distance between nuclear apex to cell apex (DNACA); the distance between cell base to nuclear apex (DCBNA); stratification index (SI)--the ratio of DCBNA and CH; and the volume density of mucous vacuoles in the reference epithelium (VVMV,EP). In comparisons of different segments within groups, the nuclei at the S segment of N and PPM crypts were more irregular and less circular in shape than nuclei from other segments. There was a shift of nuclear profile shape (NSF and NCI) from circular to ellipsiodal between B and S segments. In comparisons of similar segments between groups, no significant nuclear shape changes were detected in nuclei of PPM crypts when compared with nuclei in similar segments of N crypts and the pattern of nuclear shape alterations resembled those of normal crypts. In comparisons of different segments within groups of N and PPM crypts, AGDMAX, DNACA, DCBNA, CH and SI parameters demonstrated that epithelial cells at the I segments have more centrally positioned nuclei with the tallest epithelial height

  9. Variations of gastric transmucosal potential difference and lesion formation during hemorrhagic shock in the rat.

    PubMed

    Takeuchi, K; Ohno, T; Okabe, S

    1986-11-01

    We measured transmucosal potential difference (PD) of the stomach in anesthetized rats before, during, and after hemorrhagic shock, and investigated the effects of various drugs on the PD and gastric lesion during this period. After hemorrhagic shock, there was a decrease of PD and an increase of luminal pH in the saline-perfused stomach, the degree of these changes being dependent on a fall in the arterial blood pressure. The graded reduction of PD in response to hemorrhagic shock was similarly observed in the acid-perfused stomach as in the saline-perfused one. However, gastric lesions developed only in the former, and a significant correlation was found between the lesion index and the fall in blood pressure, the reduction in PD, or the concentration of HCl as the perfusate. Subcutaneously administered propantheline bromide (30 mg/kg) or cimetidine (100 mg/kg) had no effect on gastric lesion and PD reduction caused by hemorrhagic shock. These lesions were significantly inhibited by 16,16-dimethyl prostaglandin E2 (10 micrograms/kg) or sulindac (100 mg/kg), a scavenger of OH., and aggravated by indomethacin (1 mg/kg), with less effect on the PD reduction. Intravenous infusion of NaHCO3 (0.5 M) also significantly prevented the lesion with a concomitant suppression of the PD reduction in response to hemorrhagic shock, but these effects were significantly reversed by pretreatment of the animals with acetazolamide (50 mg/kg). These results indicate that during hemorrhagic shock the PD may largely reflect the impairment of mucosal blood flow and may be used as an indicator of mucosal vulnerability to acid, gastric lesions develop only in the presence of exogenous acid, and production of prostaglandins and superoxide radicals may be involved in the pathogenesis of gastric lesions. PMID:3019817

  10. Large change in the predicted number of small halos due to a small amplitude oscillating inflaton potential

    NASA Astrophysics Data System (ADS)

    Rodrigues, Luiz Felippe S.; Opher, Reuven

    2010-07-01

    A smooth inflaton potential is generally assumed when calculating the primordial power spectrum, implicitly assuming that a very small oscillation in the inflaton potential creates a negligible change in the predicted halo mass function. We show that this is not true. We find that a small oscillating perturbation in the inflaton potential in the slow-roll regime can alter significantly the predicted number of small halos. A class of models derived from supergravity theories gives rise to inflaton potentials with a large number of steps and many trans-Planckian effects may generate oscillations in the primordial power spectrum. The potentials we study are the simple quadratic (chaotic inflation) potential with superimposed small oscillations for small field values. Without leaving the slow-roll regime, we find that for a wide choice of parameters, the predicted number of halos change appreciably. For the oscillations beginning in the 107-108M⊙ range, for example, we find that only a 5% change in the amplitude of the chaotic potential causes a 50% suppression of the number of halos for masses between 107-108M⊙ and an increase in the number of halos for masses <106M⊙ by factors ˜15-50. We suggest that this might be a solution to the problem of the lack of observed dwarf galaxies in the range 107-108M⊙. This might also be a solution to the reionization problem where a very large number of Population III stars in low mass halos are required.

  11. Registration of N6202 soybean germplasm with high protein, good yield potential, large seed and diverse pedigree

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘N6202’ soybean [Glycine max (L.,) Merr.] was cooperatively developed and released by the USDA-ARS and the North Carolina Agricultural Research Service in 2009 as a Maturity Group VI germplasm with high-protein seed, good yield potential, large-seed size, and diverse pedigree. The unusual combinati...

  12. Practical hyperdynamics method for systems with large changes in potential energy.

    PubMed

    Hirai, Hirotoshi

    2014-12-21

    A practical hyperdynamics method is proposed to accelerate systems with highly endothermic and exothermic reactions such as hydrocarbon pyrolysis and oxidation reactions. In this method, referred to as the "adaptive hyperdynamics (AHD) method," the bias potential parameters are adaptively updated according to the change in potential energy. The approach is intensively examined for JP-10 (exo-tetrahydrodicyclopentadiene) pyrolysis simulations using the ReaxFF reactive force field. Valid boost parameter ranges are clarified as a result. It is shown that AHD can be used to model pyrolysis at temperatures as low as 1000 K while achieving a boost factor of around 10(5). PMID:25527921

  13. Practical hyperdynamics method for systems with large changes in potential energy

    NASA Astrophysics Data System (ADS)

    Hirai, Hirotoshi

    2014-12-01

    A practical hyperdynamics method is proposed to accelerate systems with highly endothermic and exothermic reactions such as hydrocarbon pyrolysis and oxidation reactions. In this method, referred to as the "adaptive hyperdynamics (AHD) method," the bias potential parameters are adaptively updated according to the change in potential energy. The approach is intensively examined for JP-10 (exo-tetrahydrodicyclopentadiene) pyrolysis simulations using the ReaxFF reactive force field. Valid boost parameter ranges are clarified as a result. It is shown that AHD can be used to model pyrolysis at temperatures as low as 1000 K while achieving a boost factor of around 105.

  14. Large-Eddy Simulations of Wind Turbine Wakes Subject to Different Atmospheric Stabilities

    NASA Astrophysics Data System (ADS)

    Churchfield, M.; Lundquist, J. K.; Lee, S.; Clifton, A.

    2014-12-01

    As a byproduct of energy extraction, wind turbines create a low-speed, turbulent wake that propagate downwind. When wind turbines are situated in a group, as in a wind plant, the interactions of these wakes with other turbines are important because wake effects decrease the efficiency of the wind plant, and they increase mechanical loads on individual turbines. Wakes propagate downstream differently depending on the inflow conditions, and these conditions are heavily dominated by atmospheric stability. For example, we know that wakes are more persistent in stable conditions than in unstable conditions. Also, stable conditions often have significant wind veer which skews wakes laterally. Different levels of turbulence intensity are associated with different atmospheric stability levels, and turbulence intensity acts to diffuse wakes and to cause wake meandering. Wake physics are complex, and to understand them better, a high-resolution representation of the flow is necessary. Measurements are difficult with current sensing equipment because of the sheer size of wakes and the unsteady atmospheric environment in which they are found. Numerical simulations complement measurements and provide a high-resolution representation of the entire three-dimensional, unsteady flow field. In this work, we use large-eddy simulation (LES), the highest fidelity type of computational fluid dynamics (CFD) feasible for high-Reynolds-number wake flow. LES directly resolves the larger, energy-containing turbulent scales and models the effects of the subgrid scales that the computational mesh cannot resolve. Our solver is based on the OpenFOAM open-source CFD toolbox. Turbines are modeled using rotating actuator lines. Here, we present our LES of the wake behind a modern 1.5 MW turbine subject to different inflow atmospheric stability. We will present results of wakes subject to stable (strongly and weakly stable), neutral, and unstable conditions. We are particularly interested in how

  15. A computationally efficient scheme for the inversion of large scale potential field data: Application to synthetic and real data

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Meng, Xiaohong; Li, Fang

    2015-12-01

    Three dimensional (3D) inversion of potential field data from large scale surveys attempts to recover density or magnetic susceptibility distribution in the subspace for geological interpretation. It is computationally challenging and is not feasible on desktop computers. We propose an integrated scheme to address this problem. We adopt adaptive sampling to compress the dataset, and the cross curve of the data compression ratio and correlation coefficient between the initial and sampled data is used to choose the damping factor for adaptive sampling. Then, the conventional inversion algorithm in model space is transformed to data space, using the identity relationship between different matrices, which greatly reduces the memory requirement. Finally, parallel computation is employed to accelerate calculation of the kernel function. We use the conjugate gradient method to minimize the objective function and a damping factor is introduced to stabilize the iterative process. A wide variety of constraint options are also considered, such as depth weighing, sparseness, and boundary limits. We design a synthetic magnetic model with three prismatic susceptibility causative bodies to demonstrate the effectiveness of the proposed scheme. Tests on synthetic data show that the proposed scheme provides significant reduction in memory and time consumption, and the inversion result is reliable. These advantages hold true for practical field magnetic data from the Hawsons mining area in Australia, verifying the effectiveness of the proposed scheme.

  16. Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources

    SciTech Connect

    Edwin A. Harvego; Michael G. McKellar; James E. O'Brien; J. Stephen Herring

    2009-09-01

    High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 °C to 950 °C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered.

  17. Implicit Large Eddy Simulation of Flow over a Corrugated Dragonfly Wing Using High-Order Spectral Difference Method

    NASA Astrophysics Data System (ADS)

    Wang, Z. J.

    2009-11-01

    Implicit large eddy simulations of flow over a corrugated dragonfly wing at a Reynolds number of 34,000 at high angles of attack have been investigated with a high-order unstructured spectral difference Navier-Stokes solver. The computational results are compared with a recent experimental study by Hu et al. Both 2D and 3D simulations are carried out to assess how realistic and reliable the 2D simulations are in comparison with 3D simulations. At the angle of attack of 16 degrees, the 2D simulation failed to predict the stall observed in the experiment, while the 3D simulation correctly predicted the stall. In addition, the 3D simulation predicted a mean lift coefficient within 5% of the experimental data. We plan to compute at least another angle of attack and compare with the experimental data. The numerical simulations demonstrated the potential of the high-order SD method in large eddy simulation of physically complex problems.

  18. Large diffuse halos in time-dependent space-charge potentials with colored noise

    SciTech Connect

    Courtlandt Bohn and Ioannis V. Sideris

    2003-05-22

    We explore the potential impact of colored noise on space-charge-induced halo formation. By coupling particle orbits to parametric resonance, colored noise due to space-charge fluctuations and/or imperfections in the beamline can eject particles to much larger amplitudes than would be inferred from parametric resonance alone.

  19. Motivation by potential gains and losses affects control processes via different mechanisms in the attentional network.

    PubMed

    Paschke, Lena M; Walter, Henrik; Steimke, Rosa; Ludwig, Vera U; Gaschler, Robert; Schubert, Torsten; Stelzel, Christine

    2015-05-01

    Attentional control in demanding cognitive tasks can be improved by manipulating the motivational state. Motivation to obtain gains and motivation to avoid losses both usually result in faster reaction times and stronger activation in relevant brain areas such as the prefrontal cortex, but little is known about differences in the underlying neurocognitive mechanisms of these types of motivation in an attentional control context. In the present functional magnetic resonance imaging (fMRI) study, we tested whether potential gain and loss as motivating incentives lead to overlapping or distinct neural effects in the attentional network, and whether one of these conditions is more effective than the other. A Flanker task with word stimuli as targets and distracters was performed by 115 healthy participants. Using a mixed blocked and event-related design allowed us to investigate transient and sustained motivation-related effects. Participants could either gain money (potential gain) or avoid losing money (potential loss) in different task blocks. Participants showed a congruency effect with increased reaction times for incongruent compared to congruent trials. Potential gain led to generally faster responses compared to the neutral condition and to stronger improvements than potential loss. Potential loss also led to shorter response times compared to the neutral condition, but participants improved mainly during incongruent and not during congruent trials. The event-related fMRI data revealed a main effect of congruency with increased activity in the left inferior frontal gyrus (IFG) and inferior frontal junction area (IFJ), the pre-supplementary motor area (pre-SMA), bilateral insula, intraparietal sulcus (IPS) and visual word form area (VWFA). While potential gain led to increased activity in a cluster of the IFJ and the VWFA only during incongruent trials, potential loss was linked to activity increases in these regions during incongruent and congruent trials. The

  20. Large-scale controls on potential respiration and denitrification in riverine floodplains

    PubMed Central

    Welti, Nina; Bondar-Kunze, Elisabeth; Singer, Gabriel; Tritthart, Michael; Zechmeister-Boltenstern, Sophie; Hein, Thomas; Pinay, Gilles

    2012-01-01

    Restoration measures of deteriorated river ecosystems generally aim at increasing the spatial heterogeneity and connectivity of these systems in order to increase biodiversity and ecosystem stability. While this is believed to benefit overall ecological integrity, consequences of such restoration projects on biogeochemical processes per se (i.e. ecosystem functioning) in fluvial systems are rarely considered. We address these issues by evaluating the characteristics of surface water connection between side arms and the main river channel in a former braided river section and the role and degree of connectivity (i.e. duration of surface water connection) on the sediment biogeochemistry. We hypothesized that potential respiration and denitrification would be controlled by the degree of hydrological connectivity, which was increased after floodplain restoration. We measured potential microbial respiration (SIR) and denitrification (DEA) and compared a degraded floodplain section of the Danube River with a reconnected and restored floodplain in the same river section. Re-establishing surface water connection altered the controls on sediment microbial respiration and denitrification ultimately impacting potential microbial activities. Meta-variables were created to characterize the effects of hydrology, morphology, and the available carbon and nutrient pools on potential microbial processing. Mantel statistics and path analysis were performed and demonstrate a hierarchy where the effects of hydrology on the available substrates and microbial processing are mediated by the morphology of the floodplain. In addition, these processes are highest in the least connected sites. Surface water connection, mediated by morphology regulates the potential denitrification rate and the ratio of N2O to N2 emissions, demonstrating the effects of restoration in floodplain systems. PMID:23565037

  1. Large current difference in Au-coated vertical silicon nanowire electrode array with functionalization of peptides

    PubMed Central

    2013-01-01

    Au-coated vertical silicon nanowire electrode array (VSNEA) was fabricated using a combination of bottom-up and top-down approaches by chemical vapor deposition and complementary metal-oxide-semiconductor process for biomolecule sensing. To verify the feasibility for the detection of biomolecules, Au-coated VSNEA was functionalized using peptides having a fluorescent probe. Cyclic voltammograms of the peptide-functionalized Au-coated VSNEA show a steady-state electrochemical current behavior. Because of the critically small dimension and vertically aligned nature of VSNEA, the current density of Au-coated VSNEA was dramatically higher than that of Au film electrodes. Au-coated VSNEA further showed a large current difference with and without peptides that was nine times more than that of Au film electrodes. These results indicate that Au-coated VSENA is highly effective device to detect peptides compared to conventional thin-film electrodes. Au-coated VSNEA can also be used as a divergent biosensor platform in many applications. PMID:24279451

  2. Large current difference in Au-coated vertical silicon nanowire electrode array with functionalization of peptides

    NASA Astrophysics Data System (ADS)

    Kim, Ilsoo; Kim, So-Eun; Han, Sanghun; Kim, Hyungsuk; Lee, Jaehyung; Jeong, Du-Won; Kim, Ju-Jin; Lim, Yong-beom; Choi, Heon-Jin

    2013-11-01

    Au-coated vertical silicon nanowire electrode array (VSNEA) was fabricated using a combination of bottom-up and top-down approaches by chemical vapor deposition and complementary metal-oxide-semiconductor process for biomolecule sensing. To verify the feasibility for the detection of biomolecules, Au-coated VSNEA was functionalized using peptides having a fluorescent probe. Cyclic voltammograms of the peptide-functionalized Au-coated VSNEA show a steady-state electrochemical current behavior. Because of the critically small dimension and vertically aligned nature of VSNEA, the current density of Au-coated VSNEA was dramatically higher than that of Au film electrodes. Au-coated VSNEA further showed a large current difference with and without peptides that was nine times more than that of Au film electrodes. These results indicate that Au-coated VSENA is highly effective device to detect peptides compared to conventional thin-film electrodes. Au-coated VSNEA can also be used as a divergent biosensor platform in many applications.

  3. Noise Reduction Potential of Large, Over-the-Wing Mounted, Advanced Turbofan Engines

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.

    2000-01-01

    As we look to the future, increasingly stringent civilian aviation noise regulations will require the design and manufacture of extremely quiet commercial aircraft. Indeed, the noise goal for NASA's Aeronautics Enterprise calls for technologies that will help to provide a 20 EPNdB reduction relative to today's levels by the year 2022. Further, the large fan diameters of modem, increasingly higher bypass ratio engines pose a significant packaging and aircraft installation challenge. One design approach that addresses both of these challenges is to mount the engines above the wing. In addition to allowing the performance trend towards large, ultra high bypass ratio cycles to continue, this over-the-wing design is believed to offer noise shielding benefits to observers on the ground. This paper describes the analytical certification noise predictions of a notional, long haul, commercial quadjet transport with advanced, high bypass engines mounted above the wing.

  4. Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes

    NASA Astrophysics Data System (ADS)

    Frias-Torres, Sarrah; Bostater, Charles R., Jr.

    2011-11-01

    Biogeographical analyses provide insights on how the Deepwater Horizon oil spill impacted large pelagic fishes. We georeferenced historical ichthyoplankton surveys and published literature to map the spawning and larval areas of bluefin tuna, swordfish, blue marlin and whale shark sightings in the Gulf of Mexico with daily satellite-derived images detecting surface oil. The oil spill covered critical areas used by large pelagic fishes. Surface oil was detected in 100% of the northernmost whale shark sightings, in 32.8 % of the bluefin tuna spawning area and 38 % of the blue marlin larval area. No surface oil was detected in the swordfish spawning and larval area. Our study likely underestimates the extend of the oil spill due to satellite sensors detecting only the upper euphotic zone and the use of dispersants altering crude oil density, but provides a previously unknown spatio-temporal analysis.

  5. Imaging of oxide charges and contact potential difference fluctuations in atomic layer deposited Al2O3 on Si

    NASA Astrophysics Data System (ADS)

    Sturm, J. M.; Zinine, A. I.; Wormeester, H.; Poelsema, Bene; Bankras, R. G.; Holleman, J.; Schmitz, J.

    2005-03-01

    Ultrathin 2.5nm high-k aluminum oxide (Al2O3) films on p-type silicon (001) deposited by atomic layer deposition (ALD) were investigated with noncontact atomic force microscopy (NC-AFM) in ultrahigh vacuum, using a conductive tip. Constant force gradient images revealed the presence of oxide charges and experimental observations at different tip-sample potentials were compared with calculations of the electric force gradient based on a spherical tip model. This model could be substantially improved by the incorporation of the image of the tip in the semiconductor substrate. Based on the signals of different oxide charges observed, a homogenous depth distribution of those charges was derived. Application of a potential difference between sample and tip was found to result in a net electric force depending on the contact potential difference (CPD) and effective tip-sample capacitance, which depends on the depletion or accumulation layer that is induced by the bias voltage. CPD images could be constructed from height-voltage spectra with active feedback. Apart from oxide charges large-scale (150-300nm lateral size) and small-scale (50-100nm) CPD fluctuations were observed, the latter showing a high degree of correlation with topography features. This correlation might be a result from the surface-inhibited growth mode of the investigated layers.

  6. Large breasts and narrow waists indicate high reproductive potential in women.

    PubMed Central

    Jasieńska, Grazyna; Ziomkiewicz, Anna; Ellison, Peter T.; Lipson, Susan F.; Thune, Inger

    2004-01-01

    Physical characteristics, such as breast size and waist-to-hip ratio (WHR), function as important features used by human males to assess female attractiveness. Males supposedly pay attention to these features because they serve as cues to fecundity and health. Here, we document that women with higher breast-to-underbreast ratio (large breasts) and women with relatively low WHR (narrow waists) have higher fecundity as assessed by precise measurements of daily levels of 17-beta-oestradiol (E2) and progesterone. Furthermore, women who are characterized by both narrow waists and large breasts have 26% higher mean E2 and 37% higher mean mid-cycle E2 levels than women from three groups with other combinations of body-shape variables, i.e. low WHR with small breasts and high WHR with either large or small breasts. Such gains in hormone levels among the preferred mates may lead to a substantial rise in the probability of conception, thus providing a significant fitness benefit. PMID:15306344

  7. Dispersal of large branchiopod cysts: Potential movement by wind from potholes on the Colorado Plateau

    USGS Publications Warehouse

    Graham, T.B.; Wirth, D.

    2008-01-01

    Wind is suspected to be a primary dispersal mechanism for large branchiopod cysts on the Colorado Plateau. We used a wind tunnel to investigate wind velocities capable of moving pothole sediment and cysts from intact and disturbed surfaces. Material moved in the wind tunnel was trapped in filters; cysts were separated from sediment and counted. Undisturbed sediment moved at velocities as low as 5.9 m s-1 (12.3 miles h-1). A single all-terrain vehicle (ATV) track increased the sediment mass collected 10-fold, with particles moving at a wind velocity of only 4.2 m s-1 (8.7 miles h-1). Cysts were recovered from every wind tunnel trial. Measured wind velocities are representative of low-wind speeds measured near Moab, Utah. Wind can move large numbers of cysts to and from potholes on the Colorado Plateau. Our results indicate that large branchiopod cysts move across pothole basins at low-wind speeds; additional work is needed to establish velocities at which cysts move between potholes. ?? 2007 Springer Science+Business Media B.V.

  8. Potential for large-bodied zooplankton and dreissenids to alter the productivity and autotrophic structure of lakes.

    PubMed

    Higgins, Scott N; Althouse, B; Devlin, S P; Vadeboncoeur, Y; Vander Zanden, M J

    2014-08-01

    While limnological studies have emphasized the importance of grazers on algal biomass and primary production in pelagic habitats, few studies have examined their potential role in altering total ecosystem primary production and it's partitioning between pelagic and benthic habitats. We modified an existing ecosystem production model to include biotic feedbacks associated with two groups of large-bodied grazers of phytoplankton (large-bodied zooplankton and dreissenid mussels) and estimated their effects on total ecosystem production (TEP), and the partitioning of TEP between phytoplankton and periphyton (autotrophic structure) across large gradients in lake size and total phosphorus (TP) concentration. Model results indicated that these filter feeders were capable of reducing whole-lake phytoplankton production by 20-70%, and increasing whole-lake benthic production between 0% and 600%. Grazer effects on TEP were constrained by lake size, trophic status, and potential feedbacks between grazing and maximum rates of benthic photosynthesis (BP(MAX)). In small (mean depth Z < 10 m) oligotrophic and mesotrophic (TP < 100 mg P/m2) lakes, both large-bodied zooplankton and dreissenids were capable of increasing the benthic fraction (Bf) by 10-50% of TEP. Small lakes were also the only systems where TEP had the potential to increase in the presence of large-bodied grazers, but such increases only occurred if grazer-induced changes in water clarity, macrophyte coverage, or nutrient availability stimulated specific growth rates of periphyton. In other scenarios, TEP declined by a maximum of 50%. In very large lakes (Z > 100 m), Bf was minor (< 10%) in the presence or absence of grazers, but increases in littoral habitat and the stimulation of benthic production in these ecosystems could be of ecological relevance because littoral zones in large lakes contain a relatively high proportion of within-lake biodiversity and are important for whole-lake food webs. PMID:25230476

  9. A conservative implicit finite difference algorithm for the unsteady transonic full potential equation

    NASA Technical Reports Server (NTRS)

    Steger, J. L.; Caradonna, F. X.

    1980-01-01

    An implicit finite difference procedure is developed to solve the unsteady full potential equation in conservation law form. Computational efficiency is maintained by use of approximate factorization techniques. The numerical algorithm is first order in time and second order in space. A circulation model and difference equations are developed for lifting airfoils in unsteady flow; however, thin airfoil body boundary conditions have been used with stretching functions to simplify the development of the numerical algorithm.

  10. Consistency of mixing height retrieved over a large spatial domain from different data sources

    NASA Astrophysics Data System (ADS)

    Biavati, Gionata; Feist, Dietrich G.

    2014-05-01

    The monitoring of GreenHouse Gases (GHG) fluxes over large domains is performed coupling measurements with transport models. A key parameter, for successfully quantifying the fluxes is the altitude of the capping inversion, or the mixing height (MH). This parameter is commonly estimated as a diagnostic variable within global models, or estimated using radiosonde data. Both these methods have problems in representing the MH. In particular the time evolution and the spatial representation are the weakest aspects. Within the context of the Integrated Carbon Observation System (ICOS), a network of measurement stations is going to be created. Together with a complete equipment of instruments for measuring GHG concentrations and meteorological quantities, it is planed to monitor the MH using ceilometers and lidars. Ceilometers are a less expensive version of lidars, they are capable to estimate aerosolic load and within almost the first two kilometers the molecular density. The estimations are obtained looking for relevant time and space fluctuations of aerosol concentration. This is equivalent to placing the MH over an strong variation of the measured signal. So the most of the algorithms for locating MH are edge detection algorithms. The evaluation of the MH, estimated with different algorithms applied to optical data, shows bad agreement with the estimate performed on radiosonde data. However, a deeper study on the automated methods used on radiosonde data reveals that the commonly used algorithms, based on different implementations of Richardson Bulk Number method, are not reliable or suitable for evaluating results of other methods. The use of optical instruments for estimating MH has several limitations: multiple edges are commonly detected and a selection criteria is required; depending on the stability of the boundary layer MH can be outside the detection limits of the instrument; clouds and other water condensations phenomena can prevent the estimation of MH

  11. Insights into the Carbon Sequestration Potential of Rangelands Through Measurement and Modeling of Differently Managed Pastures

    NASA Astrophysics Data System (ADS)

    Owen, J. J.; Hartman, M.; Parton, W. J.; Silver, W. L.

    2014-12-01

    Poor management of rangelands has led to significant soil organic matter losses globally, and contributed to increasing atmospheric CO2 concentrations. Restoring and increasing soil carbon (C) content in rangelands offers an opportunity to mitigate climate change while improving soil conditions and increasing forage production. Organic matter amendments are used to improve soil properties, but predicting the resulting changes in soil C is challenging due to the interactions between amendment characteristics, climate, and soil characteristics. We used data from 10 pasture-based dairies in California and the DayCent model to test the impact of long-term (>30 year) manure additions on soil C pools and fluxes. Soils were sampled from 26 fields which had solid, liquid, solid and liquid, or no manure additions. These field data and management information provided by the ranchers were used to model the effects of manure amends on soil C storage and loss. Soil C was significantly greater in manured fields than non-manured fields when corrected for clay content and slope. Fields with higher clay had more soil C, as did those with lower slopes, and these effects were large enough to confound the manuring effect. DayCent was able to accurately estimate total soil C when parameterized with field-specific management practices, averaging only a 10±1% difference between measurement and modeled values. Using generalized management histories for manured and non-manured fields, as would be used for regional-scale estimates, produced less accurate results with a 24±3% average difference between measurement and modeled values. Modeling alternate scenarios for each field suggested that manure amendment increased soil C and forage production by 0.6 Mg ha-1 y-1 and 0.3 Mg ha-1 y-1, respectively. Forecasting to 2100 showed that in manure-amended fields, soil C increased until 2080 before stabilization, mostly through gains in the pool with slow turnover. The "passive soil C" pool

  12. Determination of Contact Potential Difference by the Kelvin Probe (Part I) I. Basic Principles of Measurements

    NASA Astrophysics Data System (ADS)

    Vilitis, O.; Rutkis, M.; Busenberg, J.; Merkulov, D.

    2016-04-01

    Determination of electric potential difference using the Kelvin probe, i.e. vibrating capacitor technique, is one of the most sensitive measuring procedures in surface physics. Periodic modulation of distance between electrodes leads to changes in capacitance, thereby causing current to flow through the external circuit. The procedure of contactless, non-destructive determination of contact potential difference between an electrically conductive vibrating reference electrode and an electrically conductive sample is based on precise control measurement of Kelvin current flowing through a capacitor. The present research is devoted to creation of a new low-cost miniaturised measurement system to determine potential difference in real time and at high measurement resolution. Furthermore, using the electrode of a reference probe, the Kelvin method leads to both the indirect measurement of an electronic work function, or a contact potential of sample, and of a surface potential for insulator type samples. In the article, the first part of the research, i.e., the basic principles and prerequisites for establishment of such a measurement system are considered.

  13. Metabolic efficiency of Geobacter sulfurreducens growing on anodes with different redox potentials.

    PubMed

    Bosch, Julian; Lee, Keun-Young; Hong, Siang-Fu; Harnisch, Falk; Schröder, Uwe; Meckenstock, Rainer U

    2014-06-01

    Microorganisms respiring Fe(III) in the environment face a range of redox potentials of the prospective terminal ferric electron acceptors, because Fe(III) can be present in different minerals or organic complexes. We investigated the adaptation of Geobacter sulfurreducens to this range by exposing the bacteria to different redox potentials between the electron donor acetate and solid, extracellular anodes in a microbial fuel-cell set-up. Over a range of anode potentials from -0.105 to +0.645 V versus standard hydrogen electrode, G. sulfurreducens produced identical amounts of biomass per electron respired. This indicated that the organism cannot utilize higher available energies for energy conservation to ATP, and confirmed recent studies. Either the high potentials cannot be used due to physiological limitations, or G. sulfurreducens decreased its metabolic efficiency, and less biomass per unit of energy was produced. In this case, G. sulfurreducens "wasted" energy at high-potential differences, most likely as heat to fuel growth kinetics. PMID:24554342

  14. Prioritization of pharmaceuticals for potential environmental hazard through leveraging a large-scale mammalian pharmacological dataset.

    PubMed

    Berninger, Jason P; LaLone, Carlie A; Villeneuve, Daniel L; Ankley, Gerald T

    2016-04-01

    The potential for pharmaceuticals in the environment to cause adverse ecological effects is of increasing concern. Given the thousands of active pharmaceutical ingredients (APIs) that can enter the aquatic environment through human and/or animal (e.g., livestock) waste, a current challenge in aquatic toxicology is identifying those that pose the greatest risk. Because empirical toxicity information for aquatic species is generally lacking for pharmaceuticals, an important data source for prioritization is that generated during the mammalian drug development process. Applying concepts of species read-across, mammalian pharmacokinetic data were used to systematically prioritize APIs by estimating their potential to cause adverse biological consequences to aquatic organisms, using fish as an example. Mammalian absorption, distribution, metabolism, and excretion (ADME) data (e.g., peak plasma concentration, apparent volume of distribution, clearance rate, and half-life) were collected and curated, creating the Mammalian Pharmacokinetic Prioritization For Aquatic Species Targeting (MaPPFAST) database representing 1070 APIs. From these data, a probabilistic model and scoring system were developed and evaluated. Individual APIs and therapeutic classes were ranked based on clearly defined read-across assumptions for translating mammalian-derived ADME parameters to estimate potential hazard in fish (i.e., greatest predicted hazard associated with lowest mammalian peak plasma concentrations, total clearance and highest volume of distribution, half-life). It is anticipated that the MaPPFAST database and the associated API prioritization approach will help guide research and/or inform ecological risk assessment. PMID:25772004

  15. Comparative transforming potential of different human papillomaviruses associated with non-melanoma skin cancer

    SciTech Connect

    Massimi, Paola; Thomas, Miranda; Bouvard, Veronique; Ruberto, Irene; Campo, M. Saveria; Tommasino, Massimo; Banks, Lawrence

    2008-02-20

    It is well established that high-risk human papillomaviruses (HPVs) that infect mucosal epithelia are the causative agents of cervical cancer. In contrast, the association of cutaneo-tropic HPV types with the development of non-melanoma skin cancer (NMSC) is less well defined. In this study, we have analysed the in vitro transforming potential of various cutaneous HPV types. Using oncogene cooperation assays with activated ras, we have shown that diverse cutaneous types, including 12, 14, 15, 24, 36 and 49, have significant transforming potential. Interestingly, most of this activity appears to be encoded by the E6 gene product. In contrast, the common HPV-10 exhibits no significant transforming potential in these assays. This difference may be a reflection of different patterns of cellular localization, with transforming E6s being nuclear and non-transforming being cytoplasmic. These results provide molecular support for a role of these viruses in the development of certain human malignancies.

  16. Measurement of magnetic field aligned potential differences using high resolution conjugate photoelectron energy spectra

    NASA Technical Reports Server (NTRS)

    Peterson, W. K.; Doering, J. P.; Potemra, T. A.; Bostrom, C. O.; Brace, L. H.; Heelis, R. A.; Hanson, W. B.

    1977-01-01

    Simultaneous high-resolution observations of a distinctive feature in the energy spectrum of conjugate photoelectrons and spacecraft potential relative to the local ionosphere have allowed the net potential difference between magnetic conjugate points at latitudes below the region of low-energy (i.e., lower than 100 eV) auroral electron precipitation to be determined. Measurements made at 300 km from Atmosphere Explorer C show that there is normally no net potential difference between hemispheres in this region, which extended up to invariant latitudes as high as 74 deg. Two types of apparently related anomalous behavior were infrequently observed at high latitudes. During these periods the incident flux of conjugate photoelectrons was either decelerated by about 3 eV or was not detected.

  17. Comparison of methane production potential, biodegradability, and kinetics of different organic substrates.

    PubMed

    Li, Yeqing; Zhang, Ruihong; Liu, Guangqing; Chen, Chang; He, Yanfeng; Liu, Xiaoying

    2013-12-01

    The methane production potential, biodegradability, and kinetics of a wide range of organic substrates were determined using a unified and simple method. Results showed that feedstocks that contained high energy density and easily degradable substrates exhibited high methane production potential and biodegradability. Lignocellulosic biomass with high content of fibrous compositions had low methane yield and biodegradability. Feedstocks with high lignin content (≥ 15%, on a TS basis) had low first-order rate constant (0.05-0.06 1/d) compared to others. A negative linear correlation between lignin content and experimental methane yield (or biodegradability) was found for lignocellulosic and manure wastes. This could be used as a fast method to predict the methane production potential and biodegradability of fiber-rich substrates. The findings of this study provided a database for the conversion efficiency of different organic substrates and might be useful for applications of biomethane potential assay and anaerobic digestion in the future. PMID:24140354

  18. The Turn to Experience in Contemporary Art: A Potentiality for Thinking Art Education Differently

    ERIC Educational Resources Information Center

    O'Donoghue, Dónal

    2015-01-01

    This article considers the turn to experience in contemporary art and examines its potentiality for thinking art education differently. This project should not be mistaken for what Hannah Arendt (1968) identified as "the extraordinary enthusiasm for what is new" (p. 176). Rather, its purpose is to pursue another possibility for art…

  19. Greenhouse gas emission and groundwater pollution potentials of soils amended with different swine biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to study the greenhouse gas emission and groundwater pollution potentials of the soils amended with various biochars using different biomass feedstocks and thermal processing conditions. Triplicate sets of small pots were designed; control soil consisting of Histi...

  20. Differences in Mathematical Performance, Creativity Potential, and Need for Cognitive Closure between Chinese and Australian Students

    ERIC Educational Resources Information Center

    Ma, Choi-Chi Evelene; Rapee, Ronald M.

    2015-01-01

    Research has shown that Chinese students outperform students from several Western countries on mathematics performance while some evidence has suggested that Western students perform more strongly on tests of creativity. One potential mechanism for these differences may be a higher need for cognitive closure among Chinese students. The current…

  1. How to Help Children with Learning Differences Reach Their Full Potential

    ERIC Educational Resources Information Center

    Lavoie, Theresa

    2008-01-01

    This article is the third part of a 10-part series that explores Attention Deficit Hyperactivity Disorder (ADHD). It offers and discusses tips on how to help children with learning differences reach their full potential. These include: (1) start with good nutrition; (2) be sure your child is exercising; (3) make sure your child is getting enough…

  2. Potential benefits of a ceramic thermal barrier coating on large power generation gas turbine

    NASA Technical Reports Server (NTRS)

    Clark, J. S.; Nainiger, J. J.

    1977-01-01

    Thermal barrier coating design option offers benefit in terms of reduced electricity costs when used in utility gas turbines. Options considered include: increased firing temperature, increased component life, reduced cooling air requirements, and increased corrosion resistance (resulting in increased tolerance for dirty fuels). Performance and cost data were obtained. Simple, recuperated and combined cycle applications were considered, and distillate and residual fuels were assumed. The results indicate that thermal barrier coatings could produce large electricity cost savings if these coatings permit turbine operation with residual fuels at distillate-rated firing temperatures. The results also show that increased turbine inlet temperature can result in substantial savings in fuel and capital costs.

  3. A microsatellite linkage map of rainbow trout (Oncorhynchus mykiss) characterized by large sex-specific differences in recombination rates.

    PubMed

    Sakamoto, T; Danzmann, R G; Gharbi, K; Howard, P; Ozaki, A; Khoo, S K; Woram, R A; Okamoto, N; Ferguson, M M; Holm, L E; Guyomard, R; Hoyheim, B

    2000-07-01

    We constructed a genetic linkage map for a tetraploid derivative species, the rainbow trout (Oncorhynchus mykiss), using 191 microsatellite, 3 RAPD, 7 ESMP, and 7 allozyme markers in three backcross families. The linkage map consists of 29 linkage groups with potential arm displacements in the female map due to male-specific pseudolinkage arrangements. Synteny of duplicated microsatellite markers was used to identify and confirm some previously reported pseudolinkage arrangements based upon allozyme markers. Fifteen centromeric regions (20 chromosome arms) were identified with a half-tetrad analysis using gynogenetic diploids. Female map length is approximately 10 M, but this is a large underestimate as many genotyped segments remain unassigned at a LOD threshold of 3.0. Extreme differences in female:male map distances were observed (ratio F:M, 3.25:1). Females had much lower recombination rates (0.14:1) in telomeric regions than males, while recombination rates were much higher in females within regions proximal to the centromere (F:M, 10:1). Quadrivalent formations that appear almost exclusively in males are postulated to account for the observed differences. PMID:10880492

  4. Artificial neural networks approach for zeta potential of Montmorillonite in the presence of different cations

    NASA Astrophysics Data System (ADS)

    Yukselen, Yeliz; Erzin, Yusuf

    2008-05-01

    In this study, the zeta potential of montmorillonite in the presence of different chemical solutions was modeled by means of artificial neural networks (ANNs). Zeta potential of the montmorillonite was measured in the presence of salt cations, Na+, Li+ and Ca2+ and metals Zn2+, Pb2+, Cu2+, and Al3+ at different pH values, and observed values pointed to a different behavior for this mineral in the presence of salt and heavy metal cations. Artificial neural networks were successfully developed for the prediction of the zeta potential of montmorillonite in the presence of salt and heavy metal cations at different pH values and ionic strengths. Resulting zeta potential of montmorillonite shows different behavior in the presence of salt and heavy metal cations, and two ANN models were developed in order to be compared with experimental results. The ANNs results were found to be close to experimentally measured zeta potential values. The performance indices such as coefficient of determination, root mean square error, mean absolute error, and variance account for were used to control the performance of the prediction capacity of the models developed in this study. These indices obtained make it clear that the predictive models constructed are quite powerful. The constructed ANN models exhibited a high performance according to the performance indices. This performance has also shown that the ANNs seem to be a useful tool to minimize the uncertainties encountered during the soil engineering projects. For this reason, the use of ANNs may provide new approaches and methodologies.

  5. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution.

    PubMed

    Clarke, Thomas H; Garb, Jessica E; Hayashi, Cheryl Y; Arensburger, Peter; Ayoub, Nadia A

    2015-07-01

    The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae). PMID:26058392

  6. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution

    PubMed Central

    Clarke, Thomas H.; Garb, Jessica E.; Hayashi, Cheryl Y.; Arensburger, Peter; Ayoub, Nadia A.

    2015-01-01

    The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae). PMID:26058392

  7. A large-cavity zeolite with wide pore windows and potential as an oil refining catalyst.

    PubMed

    Corma, Avelino; Díaz-Cabañas, María J; Martínez-Triguero, Joaquín; Rey, Fernando; Rius, Jordi

    2002-08-01

    Crude oil is an important feedstock for the petrochemical industry and the dominant energy source driving the world economy, but known oil reserves will cover demand for no more than 50 years at the current rate of consumption. This situation calls for more efficient strategies for converting crude oil into fuel and petrochemical products. At present, more than 40% of oil conversion is achieved using catalysts based on faujasite; this zeolite requires extensive post-synthesis treatment to produce an ultrastable form, and has a large cavity accessible through four 0.74-nm-wide windows and thus limits the access of oil molecules to the catalytically active sites. The use of zeolites with better accessibility to their active sites should result in improved catalyst efficiency. To date, two zeolites with effective pore diameters exceeding that of faujasite have been reported, but their one-dimensional pore topology excludes use in oil refining. Similarly, zeolites with large pores and a three-dimensional pore topology have been reported, but in all these materials the pore openings are smaller than in faujasite. Here we report the synthesis of ITQ-21, a zeolite with a three-dimensional pore network containing 1.18-nm-wide cavities, each of which is accessible through six circular and 0.74-nm-wide windows. As expected for a zeolite with this structure, ITQ-21 exhibits high catalytic activity and selectivity for valuable products in preliminary oil refining tests. PMID:12152074

  8. Active and total microbial communities in forest soil are largely different and highly stratified during decomposition

    PubMed Central

    Baldrian, Petr; Kolařík, Miroslav; Štursová, Martina; Kopecký, Jan; Valášková, Vendula; Větrovský, Tomáš; Žifčáková, Lucia; Šnajdr, Jaroslav; Rídl, Jakub; Vlček, Čestmír; Voříšková, Jana

    2012-01-01

    Soils of coniferous forest ecosystems are important for the global carbon cycle, and the identification of active microbial decomposers is essential for understanding organic matter transformation in these ecosystems. By the independent analysis of DNA and RNA, whole communities of bacteria and fungi and its active members were compared in topsoil of a Picea abies forest during a period of organic matter decomposition. Fungi quantitatively dominate the microbial community in the litter horizon, while the organic horizon shows comparable amount of fungal and bacterial biomasses. Active microbial populations obtained by RNA analysis exhibit similar diversity as DNA-derived populations, but significantly differ in the composition of microbial taxa. Several highly active taxa, especially fungal ones, show low abundance or even absence in the DNA pool. Bacteria and especially fungi are often distinctly associated with a particular soil horizon. Fungal communities are less even than bacterial ones and show higher relative abundances of dominant species. While dominant bacterial species are distributed across the studied ecosystem, distribution of dominant fungi is often spatially restricted as they are only recovered at some locations. The sequences of cbhI gene encoding for cellobiohydrolase (exocellulase), an essential enzyme for cellulose decomposition, were compared in soil metagenome and metatranscriptome and assigned to their producers. Litter horizon exhibits higher diversity and higher proportion of expressed sequences than organic horizon. Cellulose decomposition is mediated by highly diverse fungal populations largely distinct between soil horizons. The results indicate that low-abundance species make an important contribution to decomposition processes in soils. PMID:21776033

  9. Differential response to DNA damage may explain different cancer susceptibility between small and large intestine.

    PubMed

    Hong, Mee Young; Turner, Nancy D; Carroll, Raymond J; Chapkin, Robert S; Lupton, Joanne R

    2005-07-01

    Although large intestine (LI) cancer is the second-leading cause of cancer-related deaths in the United States, small intestine (SI) cancer is relatively rare. Because oxidative DNA damage is one possible initiator of tumorigenesis, we investigated if the SI is protected against cancer because of a more appropriate response to oxidative DNA damage compared with the LI. Sixty rats were allocated to three treatment groups: 3% dextran sodium sulfate (DSS, a DNA-oxidizing agent) for 48 hrs, withdrawal (DSS for 48 hrs + DSS withdrawal for 48 hrs), or control (no DSS). The SI, compared with the LI, showed greater oxidative DNA damage (P < 0.001) as determined using a quantitative immunohistochemical analysis of 8-oxodeoxyguanosine (8-oxodG). The response to the DNA adducts in the SI was greater than in the LI. The increase of TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive apoptosis after DSS treatment was greater in the SI compared with the LI (P < 0.001), and there was a positive correlation (P = 0.031) between DNA damage and apoptosis in the SI. Morphologically, DSS caused an extensive loss of crypt structure shown in lower crypt height (P = 0.006) and the number of intact crypts (P = 0.0001) in the LI, but not in the SI. These data suggest that the SI may be more protected against cancer by having a more dynamic response to oxidative damage that maintains crypt morphology, whereas the response of the LI makes it more susceptible to loss of crypt architecture. These differential responses to oxidative DNA damage may contribute to the difference in cancer susceptibility between these two anatomic sites of the intestine. PMID:15985621

  10. Benthic Community Responses during Different Construction Stage of Large Coastal Development (Saemangeum, Republic of Korea)

    NASA Astrophysics Data System (ADS)

    Park, S.; An, S.

    2014-12-01

    The Saemangeum reclamation project in South Korea represents one of the largest construction efforts in coastal environments and provides a valuable opportunity to evaluate the benthic community responses in the large scale human disturbances. The changes of benthic ecosystems were monitored in the course of construction stage. Depending on the construction stage (Partial Closure (PC) stage: May 2004 ~Jan. 2006, Complete Closure (CC) stage: May 2006~Nov. 2006), Stable (S) stage: May 2007 ~ Aug. 2008), subtidal benthic ecosystems around Saemangeum were affected differently. In particular, the dramatic change of benthic community was observed in DI (Direct influence) area located inside the barrage. The benthic community change was temporal and minimum in the IDI (In-direct Influence) area located outside the barrage. During PC stage, the species number and density tended to increase in DI, but they rapidly decreased during CC stage. They increased again during S stage in DI but the most of the species were composed of opportunistic species indicating a deteriorated environment. In IDI, the species number and density also increased during PC stage and decreased during CC stage, but unlike DI, the increase of species number and density in S stage was not observed. In DI area, the benthic community structure had changed due to hypoxia, desalination and landization after CC stage, and the opportunistic species like Theora fragilis, Tharyx sp., Heteromastus filiformis had dominated after S-stage. In IDI area, however, abrupt environmental changes had not appeared and species number and density had been constant and species composition did not change even after the CC stage.

  11. NREL Confirms Large Potential for Grid Integration of Wind, Solar Power (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from these renewable resources could be integrated reliably into the grid. To inform the discussion about the potential of such variable sources, the National Renewable Energy Laboratory (NREL) launched two key regional studies, examining the east and west sections of the U.S. power grid. The studies show that it is technically possible for U.S. power systems to integrate 20%-35% renewable electricity if infrastructure and operational improvements can be made.

  12. A refined quartic potential energy surface and large scale vibrational calculations for S0 thiophosgene.

    PubMed

    Rashev, Svetoslav; Moule, David C

    2015-04-01

    In this work we present a full 6D quartic potential energy surface (PES) for S0 thiophosgene in curvilinear symmetrized bond-angle coordinates. The PES was refined starting from an ab initio field derived from acc-pVTZ basis set with CCSD(T) corrections for electron correlation. In the present calculations we used our variational method that was recently tested on formaldehyde and some of its isotopomers, along with additional improvements. The lower experimentally known vibrational levels for 35Cl2CS were reproduced quite well in the calculations, which can be regarded as a test for the feasibility of the obtained quartic PES. PMID:25615683

  13. Torque measurements reveal large process differences between materials during high solid enzymatic hydrolysis of pretreated lignocellulose

    PubMed Central

    2012-01-01

    Background A common trend in the research on 2nd generation bioethanol is the focus on intensifying the process and increasing the concentration of water insoluble solids (WIS) throughout the process. However, increasing the WIS content is not without problems. For example, the viscosity of pretreated lignocellulosic materials is known to increase drastically with increasing WIS content. Further, at elevated viscosities, problems arise related to poor mixing of the material, such as poor distribution of the enzymes and/or difficulties with temperature and pH control, which results in possible yield reduction. Achieving good mixing is unfortunately not without cost, since the power requirements needed to operate the impeller at high viscosities can be substantial. This highly important scale-up problem can easily be overlooked. Results In this work, we monitor the impeller torque (and hence power input) in a stirred tank reactor throughout high solid enzymatic hydrolysis (< 20% WIS) of steam-pretreated Arundo donax and spruce. Two different process modes were evaluated, where either the impeller speed or the impeller power input was kept constant. Results from hydrolysis experiments at a fixed impeller speed of 10 rpm show that a very rapid decrease in impeller torque is experienced during hydrolysis of pretreated arundo (i.e. it loses its fiber network strength), whereas the fiber strength is retained for a longer time within the spruce material. This translates into a relatively low, rather WIS independent, energy input for arundo whereas the stirring power demand for spruce is substantially larger and quite WIS dependent. By operating the impeller at a constant power input (instead of a constant impeller speed) it is shown that power input greatly affects the glucose yield of pretreated spruce whereas the hydrolysis of arundo seems unaffected. Conclusions The results clearly highlight the large differences between the arundo and spruce materials, both in terms of

  14. Potential causes of differences between ground and surface air temperature warming across different ecozones in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Majorowicz, Jacek A.; Skinner, Walter R.

    1997-10-01

    Analysis and modelling of temperature anomalies from 25 selected deep wells in Alberta show that the differences between GST (ground surface temperature) warming for the northern Boreal Forest ecozone and the combined Prairie Grassland ecozone and Aspen Parkland transition region to the south occur during the latter half of this century. This corresponds with recent changes in surface albedo resulting from permanent land development in the northern areas and also to increases in natural forest fires in the past 20 years. Differences between GST and SAT (surface air temperature) warming are much higher in the Boreal Forest ecozone than in the Prairie Grassland ecozone and Aspen Parkland transition region. Various hypotheses which could account for the existing differences between the GST and SAT warming in the different ecozones of Alberta, and western Canada in general, are tested. Analysis of existing data on soil temperature, hydrological piezometric surfaces, snowfall and moisture patterns, and land clearing and forest fires, indicate that large areas of Alberta, characterised by anomalous GST warming, have experienced widespread changes to the surface landscape in this century. It is postulated that this has resulted in a lower surface albedo with a subsequent increase in the absorption of solar energy. Heat flow modelling shows that, after climatic SAT warming, permanent clearing of the land is the most effective and likely cause of the observed changes in the GST warming. The greater GST warming in the Boreal Forest ecozone in the latter half of this century is related to landscape change due to land development and increasing forest fire activity. It appears to account for a portion of the observed SAT warming in this region through a positive feedback loop with the overlying air. The anthropogenic effect on regional climatic warming through 20th century land clearing and landscape alteration requires further study. In future, more accurate quantification of

  15. COMMUNALITIES AND DIFFERENCES IN FEAR POTENTIATION BETWEEN CARDIAC DEFENSE AND EYE-BLINK STARTLE

    PubMed Central

    Sánchez, María B.; Guerra, Pedro; Muñoz, Miguel A.; Mata, José Luís; Bradley, Margaret M.; Lang, Peter J.; Vila, Jaime

    2009-01-01

    This study examines similarities and differences in fear potentiation between two protective reflexes: cardiac defense and eye-blink startle. Women reporting intense fear of animals but low fear of blood or intense fear of blood but low fear of animals viewed pictures depicting blood or the feared animal for 6 s in 2 separate trials in counterbalanced order. An intense burst of white noise, able to elicit both a cardiac defense response and a reflexive startle blink, was presented 3.5 s after picture onset. Both cardiac and blink responses were potentiated when highly fearful individuals viewed fearful pictures. However, differences appeared concerning picture order. This pattern of results indicates communalities and differences among protective reflexes that are relevant for understanding the dynamics of emotional reflex modulation. PMID:19572906

  16. Generation Mechanism of Earth Potential Difference Signal during Seismic Wave Propagation and its Observation Condition

    NASA Astrophysics Data System (ADS)

    Okubo, Kan; Yamamoto, Keisuke; Takayama, Masakazu; Takeuchi, Nobunao

    We have observed the co-seismic electromagnetic phenomena such as earth potential difference (EPD) variation in many observation sites of both Miyagi and Akita Prefectures. So far, in any earthquakes we observed clear signals of the EPD variation. However, the amplitude of observed EPD signals are very different at each site. To explain this difference, firstly we assumed the EPD generation mechanism to be the streaming potential. Secondarily, the underground circumstance is modeled as the composer of groundwater table, capillary tubes and fine tubes. The model how EPD variation signals appear is postulated to explain the observed data. The relative position of the ground water table against the buried electrodes is examined to explain the observed data. The groundwater table may be very sensitive to the appearance of the EPD variation. If electrodes were buried a few meters below the ground surface, we could observe the EPD signals in the case of shallow groundwater table.

  17. Large sex differences in chicken behavior and brain gene expression coincide with few differences in promoter DNA-methylation.

    PubMed

    Nätt, Daniel; Agnvall, Beatrix; Jensen, Per

    2014-01-01

    While behavioral sex differences have repeatedly been reported across taxa, the underlying epigenetic mechanisms in the brain are mostly lacking. Birds have previously shown to have only limited dosage compensation, leading to high sex bias of Z-chromosome gene expression. In chickens, a male hyper-methylated region (MHM) on the Z-chromosome has been associated with a local type of dosage compensation, but a more detailed characterization of the avian methylome is limiting our interpretations. Here we report an analysis of genome wide sex differences in promoter DNA-methylation and gene expression in the brain of three weeks old chickens, and associated sex differences in behavior of Red Junglefowl (ancestor of domestic chickens). Combining DNA-methylation tiling arrays with gene expression microarrays we show that a specific locus of the MHM region, together with the promoter for the zinc finger RNA binding protein (ZFR) gene on chromosome 1, is strongly associated with sex dimorphism in gene expression. Except for this, we found few differences in promoter DNA-methylation, even though hundreds of genes were robustly differentially expressed across distantly related breeds. Several of the differentially expressed genes are known to affect behavior, and as suggested from their functional annotation, we found that female Red Junglefowl are more explorative and fearful in a range of tests performed throughout their lives. This paper identifies new sites and, with increased resolution, confirms known sites where DNA-methylation seems to affect sexually dimorphic gene expression, but the general lack of this association is noticeable and strengthens the view that birds do not have dosage compensation. PMID:24782041

  18. Large Sex Differences in Chicken Behavior and Brain Gene Expression Coincide with Few Differences in Promoter DNA-Methylation

    PubMed Central

    Nätt, Daniel; Agnvall, Beatrix; Jensen, Per

    2014-01-01

    While behavioral sex differences have repeatedly been reported across taxa, the underlying epigenetic mechanisms in the brain are mostly lacking. Birds have previously shown to have only limited dosage compensation, leading to high sex bias of Z-chromosome gene expression. In chickens, a male hyper-methylated region (MHM) on the Z-chromosome has been associated with a local type of dosage compensation, but a more detailed characterization of the avian methylome is limiting our interpretations. Here we report an analysis of genome wide sex differences in promoter DNA-methylation and gene expression in the brain of three weeks old chickens, and associated sex differences in behavior of Red Junglefowl (ancestor of domestic chickens). Combining DNA-methylation tiling arrays with gene expression microarrays we show that a specific locus of the MHM region, together with the promoter for the zinc finger RNA binding protein (ZFR) gene on chromosome 1, is strongly associated with sex dimorphism in gene expression. Except for this, we found few differences in promoter DNA-methylation, even though hundreds of genes were robustly differentially expressed across distantly related breeds. Several of the differentially expressed genes are known to affect behavior, and as suggested from their functional annotation, we found that female Red Junglefowl are more explorative and fearful in a range of tests performed throughout their lives. This paper identifies new sites and, with increased resolution, confirms known sites where DNA-methylation seems to affect sexually dimorphic gene expression, but the general lack of this association is noticeable and strengthens the view that birds do not have dosage compensation. PMID:24782041

  19. Large differences in the genome organization of different plant Trypanosomatid parasites (Phytomonas spp.) reveal wide evolutionary divergences between taxa.

    PubMed

    Marín, C; Dollet, M; Pagès, M; Bastien, P

    2009-03-01

    All currently known plant trypanosomes have been grouped in the genus Phytomonas spp., although they can differ greatly in terms of both their biological properties and effects upon the host. Those parasitizing the phloem sap are specifically associated with lethal syndromes in Latin America, such as, phloem necrosis of coffee, 'Hartrot' of coconut and 'Marchitez sorpresiva' of oil palm, that inflict considerable economic losses in endemic countries. The genomic organization of one group of Phytomonas (D) considered as representative of the genus has been published previously. The present work presents the genomic structure of two representative isolates from the pathogenic phloem-restricted group (H) of Phytomonas, analyzed by pulsed field gel electrophoresis followed by hybridization with chromosome-specific DNA markers. It came as a surprise to observe an extremely different genomic organization in this group as compared with that of group D. Most notably, the chromosome number is 7 in this group (with a genome size of 10 Mb) versus 21 in the group D (totalling 25 Mb). These data unravel an unsuspected genomic diversity within plant trypanosomatids, that may justify a further debate about their division into different genera. PMID:19111630

  20. Lower ionosphere large positive and negative ions are still puzzling: A potential role in ion induced aerosol formation

    NASA Astrophysics Data System (ADS)

    Arnold, Frank

    2016-04-01

    Inspired by greatly improved possibilities in future rocket borne high mass resolution ion mass spectrometry, previous pioneering rocket borne ion-mass spectrometer measurements, made by our MPIK-Heidelberg research group in the lower ionosphere, are revisited and reanalyzed. Here the focus is placed upon puzzling observations of lower ionosphere large positive and large negative ions. These have a role in lower ionosphere free electron removal. They also have a potential role in lower ionosphere aerosol and eventually even cloud formation. Measurements and model simulations are presented.

  1. Potential Impacts of Precipitation Change on Large-Scale Patterns of Tree Diversity

    NASA Astrophysics Data System (ADS)

    Konar, M.; Muneepeerakul, R.; Azaele, S.; Bertuzzo, E.; Rinaldo, A.; Rodriguez-Iturbe, I.

    2010-12-01

    Forests are globally important ecosystems host to outstanding biological diversity. Widespread efforts have addressed the impacts of climate change on biodiversity in these ecosystems. We show that a metacommunity model founded on basic ecological processes offers direct linkage from large-scale forcing, such as precipitation, to tree diversity patterns of the Mississippi-Missouri River System and its sub-regions. We quantify changes in tree diversity patterns under various projected precipitation patterns, resulting in a range of responses. Uncertainties accompanying global climate models necessitate the use of scenarios of biodiversity. Here, we present results from scenarios with the largest losses and gains in tree diversity. Our results suggest that species losses under scenarios with the most dramatic contractions tend to be greater in magnitude, spatial extent, and statistical significance than gains under alternative scenarios. These findings are expected to have important implications for conservation policy and resource management.

  2. Potential impacts of precipitation change on large-scale patterns of tree diversity

    NASA Astrophysics Data System (ADS)

    Konar, M.; Muneepeerakul, R.; Azaele, S.; Bertuzzo, E.; Rinaldo, A.; Rodriguez-Iturbe, I.

    2010-11-01

    Forests are globally important ecosystems host to outstanding biological diversity. Widespread efforts have addressed the impacts of climate change on biodiversity in these ecosystems. We show that a metacommunity model founded on basic ecological processes offers direct linkage from large-scale forcing, such as precipitation, to tree diversity patterns of the Mississippi-Missouri River System and its subregions. We quantify changes in tree diversity patterns under various projected precipitation patterns, resulting in a range of responses. Uncertainties accompanying global climate models necessitate the use of scenarios of biodiversity. Here we present results from scenarios with the largest losses and gains in tree diversity. Our results suggest that species losses under scenarios with the most dramatic contractions tend to be greater in magnitude, spatial extent, and statistical significance than gains under alternative scenarios. These findings are expected to have important implications for conservation policy and resource management.

  3. Estimating Demand Response Market Potential Among Large Commercialand Industrial Customers:A Scoping Study

    SciTech Connect

    Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers, Peter

    2007-01-01

    Demand response is increasingly recognized as an essentialingredient to well functioning electricity markets. This growingconsensus was formalized in the Energy Policy Act of 2005 (EPACT), whichestablished demand response as an official policy of the U.S. government,and directed states (and their electric utilities) to considerimplementing demand response, with a particular focus on "price-based"mechanisms. The resulting deliberations, along with a variety of stateand regional demand response initiatives, are raising important policyquestions: for example, How much demand response is enough? How much isavailable? From what sources? At what cost? The purpose of this scopingstudy is to examine analytical techniques and data sources to supportdemand response market assessments that can, in turn, answer the secondand third of these questions. We focus on demand response for large(>350 kW), commercial and industrial (C&I) customers, althoughmany of the concepts could equally be applied to similar programs andtariffs for small commercial and residential customers.

  4. Termites: a potentially large source of atmospheric methane, carbon dioxide, and molecular hydrogen

    SciTech Connect

    Zimmerman, P.R.; Greenberg, J.P.; Wandiga, S.O.; Crutzen, P.J.

    1982-11-01

    Termites are emitting large quantities of CH/sub 4/, CO/sub 2/, and H/sub 2/ into the atmosphere, especially in cleared tropical forest areas. Researchers estimate that these annual global emissions could amount to 0.3 trillion lb of CH/sub 4/, 11 trillion lb of CO/sub 2/ (more than twice the net global input from fossil-fuel combustion), and 0.4 trillion lb of H/sub 2/. However, they stress that because of many uncertainties, the acutal production of these gases could vary by a factor of two; i.e., methane production could range from 0.2 to 0.7 trillion lb. Occurring on about two-thirds of the earth's

  5. Pericyte plasticity - comparative investigation of the angiogenic and multilineage potential of pericytes from different human tissues.

    PubMed

    Herrmann, M; Bara, J J; Sprecher, C M; Menzel, U; Jalowiec, J M; Osinga, R; Scherberich, A; Alini, M; Verrier, S

    2016-01-01

    Pericyte recruitment is essential for the stability of newly formed vessels. It was also suggested that pericytes represent common ancestor cells giving rise to mesenchymal stem cells (MSCs) in the adult. Here, we systematically investigated pericytes and MSCs from different human tissues in terms of their angiogenic and multilineage differentiation potential in vitro in order to assess the suitability of the different cell types for the regeneration of vascularised tissues. Magnetic-activated cell sorting (MACS®) was used to enrich CD34-CD146+ pericytes from adipose tissue (AT) and bone marrow (BM). The multilineage potential of pericytes was assessed by testing their capability to differentiate towards osteogenic, adipogenic and chondrogenic lineage in vitro. Pericytes and endothelial cells were co-seeded on Matrigel™ and the formation of tube-like structures was examined to study the angiogenic potential of pericytes. MSCs from AT and BM were used as controls. CD34-CD146+ cells were successfully enriched from AT and BM. Only BM-derived cells exhibited trilineage differentiation potential. AT-derived cells displayed poor chondrogenic differentiation upon stimulation with transforming growth factor-β1. Interestingly, osteogenic differentiation was more efficient in AT-PC and BM-PC compared to the respective full MSC population. Matrigel™ assays revealed that pericytes from all tissues integrated into tube-like structures. We show that MACS®-enriched pericytes from BM and AT have the potential to regenerate tissues of different mesenchymal lineages and support neovascularisation. MACS® represents a simple enrichment strategy of cells, which is of particular interest for clinical application. Finally, our results suggest that the regenerative potential of pericytes depends on their tissue origin, which is an important consideration for future studies. PMID:27062725

  6. [Measurement of nasal transepithelial potential difference: a diagnostic test for cystic fibrosis].

    PubMed

    Charfi, M R; Matran, R; Regnard, J; Lockhart, A

    1996-01-01

    Measurement of nasal transepithelial potential difference allows the exploration of transepithelial ionic transports in vivo. Cystic fibrosis is an interesting indication of this test. Indeed, this disease is characterized by a chloride and water secretion deficit across respiratory epithelium. We have measured nasal potential in 8 healthy volunteers. Measurements were repeated 3 times a day, during 3 days for each subject. The reproducibility of the data was analysed with factorial variance model. The mean nasal potential in the healthy volunteers group and in 10 patients with cystic fibrosis was compared. In the cystic fibrosis group, the nasal potential was measured 3 times with a 2 mn-interval between the measurements. No significant variation of the nasal potential values was found from day to day or in the same day from one measurement to another. Mean value was -19 +/- 3.5 mv in normal subjects and -42.6 +/- 5.1 mv in cystic fibrosis patients. We conclude that nasal potential measurement is an easy and reproducible test that might be a complementary tool routinely used along with the classical tests in the diagnosis of cystic fibrosis. PMID:8731749

  7. Exploring the Potential of Large Scale Distributed Modeling of Snow Accumulation and Melt on GPUs

    NASA Astrophysics Data System (ADS)

    Bisht, G.; Kumar, M.

    2010-12-01

    Water from snow melt is a critical resource in watersheds of the western US, Canada, and other similar regions of the world. The distribution of snow and melt-water controls the temporal and spatial distributions of soil moisture, evapo-transpiration (ET), recharge, stream-aquifer interaction and other hydrologic processes within the watershed. It also influences the quantity and timing of water availability in downstream areas. In spite of the serious impacts on the water resources at multiple scales, the knowledge base for prediction of snow accumulation and melt in mountainous watersheds is notably weak. Physics-based, distributed snow models such as UEB, SNTHERM, SHAW and ISNOBAL, have positioned themselves as an appropriate tool for understanding of snow-process interactions and prediction of melt, and have been applied in numerous watersheds to varying degrees of success. In spite of the significant advances in hardware speed and programming efficiency, the application of the above-mentioned snow models has mostly been limited to small watersheds. Application of these models at finer spatio-temporal resolution, in large domains, and for longer time periods, to address problems such as quantifying the response of snow-dominated watersheds to climate change scenarios, is restrictive due to the large computational cost involved. Additionally, the computational requirement of current generation snow models is expected to rise as improved snow-depth characterization and a tighter coupling with hydrologic processes are incorporated. This poses considerable challenge to their application in feasible time. We suggest alleviating this problem by taking advantage of high performance computing (HPC) systems based on Graphics Processing Unit (GPU) processors. High performance GPUs work like SIMD processors, but can take advantage of larger number of cores thus providing higher throughput. As of June 2010, the second fastest supercomputer in the world uses NVidia Tesla

  8. Iterative method for the numerical prediction of heat transfer in problems involving large differences in thermal conductivities

    SciTech Connect

    Kelkar, K.M. )

    1990-01-01

    Heat exchange that occurs between materials with largely differing thermal conductivities is commonly encountered in engineering practice.Conventional iterative solution methods perform poorly for the numerical solution for such problems. Results for computations for test problems indicate that the proposed solution procedure enables efficient solution of heat transfer problems with large conductivity differences for which the conventional line-by-line method proves ineffective.

  9. Tuning Chemical Potential Difference across Alternately Doped Graphene p-n Junctions for High-Efficiency Photodetection.

    PubMed

    Lin, Li; Xu, Xiang; Yin, Jianbo; Sun, Jingyu; Tan, Zhenjun; Koh, Ai Leen; Wang, Huan; Peng, Hailin; Chen, Yulin; Liu, Zhongfan

    2016-07-13

    Being atomically thin, graphene-based p-n junctions hold great promise for applications in ultrasmall high-efficiency photodetectors. It is well-known that the efficiency of such photodetectors can be improved by optimizing the chemical potential difference of the graphene p-n junction. However, to date, such tuning has been limited to a few hundred millielectronvolts. To improve this critical parameter, here we report that using a temperature-controlled chemical vapor deposition process, we successfully achieved modulation-doped growth of an alternately nitrogen- and boron-doped graphene p-n junction with a tunable chemical potential difference up to 1 eV. Furthermore, such p-n junction structure can be prepared on a large scale with stable, uniform, and substitutional doping and exhibits a single-crystalline nature. This work provides a feasible method for synthesizing low-cost, large-scale, high efficiency graphene p-n junctions, thus facilitating their applications in optoelectronic and energy conversion devices. PMID:27351273

  10. Isotropic Negative Area Compressibility over Large Pressure Range in Potassium Beryllium Fluoroborate and its Potential Applications in Deep Ultraviolet Region.

    PubMed

    Jiang, Xingxing; Luo, Siyang; Kang, Lei; Gong, Pifu; Yao, Wenjiao; Huang, Hongwei; Li, Wei; Huang, Rongjin; Wang, Wei; Li, Yanchun; Li, Xiaodong; Wu, Xiang; Lu, Peixiang; Li, Laifeng; Chen, Chuangtian; Lin, Zheshuai

    2015-09-01

    Isotropic negative area compressibility, which is very rare, is observed in KBBF and the related mechanism is investigated by combined high-pressure X-ray diffraction (XRD) experiments and first-principles calculations. The strong mechanical anisotropy leads to a large Poisson's ratio and high figure of merit for the acoustic-optics effect, giving KBBF potential applications as smart strain converters and deep-ultraviolet (DUV) acoustic-optic devices. PMID:26184364

  11. Potential nucleation scavenging of smoke particles over large fires: A parametric study

    SciTech Connect

    Edwards, L L; Penner, J E

    1987-08-01

    During hypothesized nuclear exchanges massive fires may be ignited and inject large amounts of smoke into the atmosphere. Considerable evidence has been accumulated to suggest that nucleation scavenging where smoke particles serve as cloud condensation nuclei (CCN) may be an important mechanism for incorporating these particles into cloud water. The fraction of smoke particles that act as CCN depends on the cloud environment as well as the affinity of the smoke particles to water. A numerical model of the detailed microphysics of condensation growth on aerosol and cloud drop distributions is employed to produce a parametric study of the dependence of nucleation to a range of conditions. We consider aerosol number concentrations of 10/sup 9//m/sup 3/ to 10/sup 13//m/sup 3/, updraft speeds from 1 to 100 m/s and aerosol particles from fully water soluble to insoluble but wettable. The study provides insight into how well we must characterize smoke particles in order to predict the fraction that act as CCN given the dynamical environment.

  12. Planktic Tychonema (Cyanobacteria) in the large lakes south of the Alps: phylogenetic assessment and toxigenic potential.

    PubMed

    Salmaso, Nico; Cerasino, Leonardo; Boscaini, Adriano; Capelli, Camilla

    2016-10-01

    This work allowed assessing a widespread occurrence of Tychonema bourrellyi in the largest lakes south of the Alps (Garda, Iseo, Como and Maggiore). The taxonomy of the species was confirmed adopting a polyphasic approach, which included microscopic examinations, molecular (16S rRNA and rbcLX sequences) and (Lake Garda) ecological characterisations. Over 70% of the 36 isolates of Tychonema sampled from the four lakes tested positive for the presence of genes implicated in the biosynthesis of anatoxins (anaF and/or anaC) and for the production of anatoxin-a (ATX) and homoanatoxin-a (HTX). A detailed analysis carried out in Lake Garda showed strong ongoing changes in the cyanobacterial community, with populations of Tychonema developing with higher biovolumes compared to the microcystins (MCs) producer Planktothrix rubescens Moreover, the time × depth distribution of Tychonema was paralleled by a comparable distribution of ATX and HTX. The increasing importance of Tychonema in Lake Garda was also suggested by the opposite trends of ATX and MCs observed since 2009. These results suggest that radical changes are occurring in the largest lakes south of the Alps. Their verification and implications will require to be assessed by extending a complete experimental work to the other large perialpine lakes. PMID:27402712

  13. Large Scale Flow-Mediated Formation and Potential Applications of Surface Nanodroplets.

    PubMed

    Yu, Haitao; Peng, Shuhua; Lei, Lei; Zhang, Jiwei; Greaves, Tamar L; Zhang, Xuehua

    2016-08-31

    Microscopic droplets located on a solid substrate in contact with an immiscible liquid promise a broad range of applications in miniaturized analytical techniques, fabrication of antireflective coatings, high-resolution near-field imaging techniques, and many others. A simple method of producing oil nanodroplets with desirable morphology is a bottom-up approach called solvent exchange, where nanodroplets nucleate and grow, as a good solvent of oil is displaced by a poor solvent. In this work, we have achieved the production of surface nanodroplets over a large surface area on planar or curved surfaces, guided by the principles of the solvent exchange. The droplet size is uniform over the entire surface of a planar or curved substrate and tunable. The production rate is extremely high at 10(6) nanodroplets per second. This advance in the nanodroplet production provides a general platform for droplet-based applications. Here we demonstrate that the application of surface nanodroplets in microextraction of hydrophobic solute (dye) from its highly diluted aqueous solution and in situ detection of the dye in a simple process, and in fabrication of highly ordered array of microlens arrays and polymer-capped microstructures by simple processes. PMID:27500306

  14. Dominant forest tree species are potentially vulnerable to climate change over large portions of their range even at high latitudes.

    PubMed

    Périé, Catherine; de Blois, Sylvie

    2016-01-01

    Projecting suitable conditions for a species as a function of future climate provides a reasonable, although admittedly imperfect, spatially explicit estimate of species vulnerability associated with climate change. Projections emphasizing range shifts at continental scale, however, can mask contrasting patterns at local or regional scale where management and policy decisions are made. Moreover, models usually show potential for areas to become climatically unsuitable, remain suitable, or become suitable for a particular species with climate change, but each of these outcomes raises markedly different ecological and management issues. Managing forest decline at sites where climatic stress is projected to increase is likely to be the most immediate challenge resulting from climate change. Here we assess habitat suitability with climate change for five dominant tree species of eastern North American forests, focusing on areas of greatest vulnerability (loss of suitability in the baseline range) in Quebec (Canada) rather than opportunities (increase in suitability). Results show that these species are at risk of maladaptation over a remarkably large proportion of their baseline range. Depending on species, 5-21% of currently climatically suitable habitats are projected to be at risk of becoming unsuitable. This suggests that species that have traditionally defined whole regional vegetation assemblages could become less adapted to these regions, with significant impact on ecosystems and forest economy. In spite of their well-recognised limitations and the uncertainty that remains, regionally-explicit risk assessment approaches remain one of the best options to convey that message and the need for climate policies and forest management adaptation strategies. PMID:27478706

  15. Dominant forest tree species are potentially vulnerable to climate change over large portions of their range even at high latitudes

    PubMed Central

    de Blois, Sylvie

    2016-01-01

    Projecting suitable conditions for a species as a function of future climate provides a reasonable, although admittedly imperfect, spatially explicit estimate of species vulnerability associated with climate change. Projections emphasizing range shifts at continental scale, however, can mask contrasting patterns at local or regional scale where management and policy decisions are made. Moreover, models usually show potential for areas to become climatically unsuitable, remain suitable, or become suitable for a particular species with climate change, but each of these outcomes raises markedly different ecological and management issues. Managing forest decline at sites where climatic stress is projected to increase is likely to be the most immediate challenge resulting from climate change. Here we assess habitat suitability with climate change for five dominant tree species of eastern North American forests, focusing on areas of greatest vulnerability (loss of suitability in the baseline range) in Quebec (Canada) rather than opportunities (increase in suitability). Results show that these species are at risk of maladaptation over a remarkably large proportion of their baseline range. Depending on species, 5–21% of currently climatically suitable habitats are projected to be at risk of becoming unsuitable. This suggests that species that have traditionally defined whole regional vegetation assemblages could become less adapted to these regions, with significant impact on ecosystems and forest economy. In spite of their well-recognised limitations and the uncertainty that remains, regionally-explicit risk assessment approaches remain one of the best options to convey that message and the need for climate policies and forest management adaptation strategies. PMID:27478706

  16. The effect of siblings on early development: a potential contributor to personality differences in mammals.

    PubMed

    Hudson, Robyn; Bautista, Amando; Reyes-Meza, Verónica; Montor, Jorge Morales; Rödel, Heiko G

    2011-09-01

    Although most mammals grow up in the company of same or different age sibs (or half sibs), surprisingly little attention has been given to how relations among them might influence the development of individual differences in morphology, physiology, and behavior. Here we review evidence from our work on domestic and wild European rabbits, and more recently on laboratory rats, mice, and domestic cats, supporting the proposition that in mammals early sibling relations contribute to the development of individual differences in these three domains and thereby to long-term behavioral differences of the kind we might consider part of an animal's behavioral style or personality. First we report a consistent and marked negative relation between litter size and individuals' body mass at birth and weaning, as well as marked within-litter differences in prenatal body mass and placental efficiency. We then report individual differences in preweaning behaviors associated with these morphological variables such as position occupied in the litter huddle and development of motor ability, as well as physiological differences in thermoregulation, immune parameters, and endocrine indicators of stress. Finally, we report first evidence from wild rabbits that early relations among littermates may have long-term consequences for individual differences in behavioral style. We conclude that in mammals, individual differences in early growth, physiology and behavior potentially important for the development of animal personality, are shaped to an appreciable extent by early sibling relations and that this little-researched field deserves closer attention. PMID:21866540

  17. The multigrid POTFIT (MGPF) method: grid representations of potentials for quantum dynamics of large systems.

    PubMed

    Peláez, Daniel; Meyer, Hans-Dieter

    2013-01-01

    In this article, a new method, multigrid POTFIT (MGPF), is presented. MGPF is a grid-based algorithm which transforms a general potential energy surface into product form, that is, a sum of products of one-dimensional functions. This form is necessary to profit from the computationally advantageous multiconfiguration time-dependent Hartree method for quantum dynamics. MGPF circumvents the dimensionality related issues present in POTFIT [A. Jäckle and H.-D. Meyer, J. Chem. Phys. 104, 7974 (1996)], allowing quantum dynamical studies of systems up to about 12 dimensions. MGPF requires the definition of a fine grid and a coarse grid, the latter being a subset of the former. The MGPF approximation relies on a series of underlying POTFIT calculations on grids which are smaller than the fine one and larger than or equal to the coarse one. This aspect makes MGPF a bit less accurate than POTFIT but orders of magnitude faster and orders of magnitude less memory demanding than POTFIT. Moreover, like POTFIT, MGPF is variational and provides an efficient error control. PMID:23298029

  18. Potential Synaptic Connectivity of Different Neurons onto Pyramidal Cells in a 3D Reconstruction of the Rat Hippocampus

    PubMed Central

    Ropireddy, Deepak; Ascoli, Giorgio A.

    2011-01-01

    Most existing connectomic data and ongoing efforts focus either on individual synapses (e.g., with electron microscopy) or on regional connectivity (tract tracing). An individual pyramidal cell (PC) extends thousands of synapses over macroscopic distances (∼cm). The contrasting requirements of high-resolution and large field of view make it too challenging to acquire the entire synaptic connectivity for even a single typical cortical neuron. Light microscopy can image whole neuronal arbors and resolve dendritic branches. Analyzing connectivity in terms of close spatial appositions between axons and dendrites could thus bridge the opposite scales, from synaptic level to whole systems. In the mammalian cortex, structural plasticity of spines and boutons makes these “potential synapses” functionally relevant to learning capability and memory capacity. To date, however, potential synapses have only been mapped in the surrounding of a neuron and relative to its local orientation rather than in a system-level anatomical reference. Here we overcome this limitation by estimating the potential connectivity of different neurons embedded into a detailed 3D reconstruction of the rat hippocampus. Axonal and dendritic trees were oriented with respect to hippocampal cytoarchitecture according to longitudinal and transversal curvatures. We report the potential connectivity onto PC dendrites from the axons of a dentate granule cell, three CA3 PCs, one CA2 PC, and 13 CA3b interneurons. The numbers, densities, and distributions of potential synapses were analyzed in each sub-region (e.g., CA3 vs. CA1), layer (e.g., oriens vs. radiatum), and septo-temporal location (e.g., dorsal vs. ventral). The overall ratio between the numbers of actual and potential synapses was ∼0.20 for the granule and CA3 PCs. All potential connectivity patterns are strikingly dependent on the anatomical location of both pre-synaptic and post-synaptic neurons. PMID:21779242

  19. Do differences in carbon allocation strategy account for large difference in productivity among four tropical Eucalyptus plantations?

    NASA Astrophysics Data System (ADS)

    Epron, D.; Nouvellon, Y.; Laclau, J.; Kinana, A.; Mazoumbou, J.; Almeida, J. D.; Deleporte, P.; Gonçalves, J.; Bouillet, J.

    2010-12-01

    The increasing demand for wood products is not satisfied by natural forests, and forest plantations are expected to provide a larger part of the global wood supply in the future. Eucalyptus is the dominant species planted in the tropics. Intensification of wood production will rely mainly on gain of productivity and on extension of afforested area on marginal zones. Wood production does not only depend on gross primary production (GPP) but also on carbon partitioning between growth (NPP) and respiration, and on NPP partitioning among the different plant organs (allocation). Less than one third of GPP is allocated to wood production in planted forest ecosystems and we hypothesized that this fraction varies among genotypes, or because of soil fertility, in relation to productivity. The partitioning of aboveground NPP between leaf, branch and stem growth was compared in four Eucalyptus plantations located in Congo and Brazil over an entire rotation (6 years). In addition, total below ground carbon allocation was estimated from soil respiration and litter fall measurements. Two clones differing in productivity were studies in Congo where productivity is known to be much less important than in Brazil. Two plots (fertilized or not with K) were studied in Brazil. In Congo, the wood production was twice higher in the most productive clone (UG) compared to the less productive one (PF1). This was due to a higher aboveground NPP, the surplus being allocated to wood production. In addition, an increase in leaf lifespan reduced the amount of carbon allocated to leaf production. Similar conclusions can be drawn when comparing K+ fertilised and control stand in Brazil where most of the surplus of aboveground NPP in fertilised plots was allocated to wood production and where leaf lifespan was also increased. Soil respiration increased in both sites with increasing NPP reflecting that more carbon is allocated below ground in these stands. A better understanding of genetic and

  20. Semiconducting large bandgap oxides as potential thermoelectric materials for high-temperature power generation?

    NASA Astrophysics Data System (ADS)

    Backhaus-Ricoult, M.; Rustad, J.; Moore, L.; Smith, C.; Brown, J.

    2014-08-01

    Semiconducting large bandgap oxides are considered as interesting candidates for high-temperature thermoelectric power generation (700-1,200 °C) due to their stability, lack of toxicity and low cost, but so far they have not reached sufficient performance for extended application. In this review, we summarize recent progress on thermoelectric oxides, analyze concepts for tuning semiconductor thermoelectric properties with view of their applicability to oxides and determine key drivers and limitations for electrical and thermal transport properties in oxides based on our own experimental work and literature results. For our experimental assessment, we have selected representative multicomponent oxides that range from materials with highly symmetric crystal structure (SrTiO3 perovskite) over oxides with large densities of planar crystallographic defects (Ti n O2 n-1 Magnéli phases with a single type of shear plane, NbO x block structures with intersecting shear planes and WO3- x with more defective block and channel structures) to layered superstructures (Ca3Co4O9 and double perovskites) and also include a wide range of their composites with a variety of second phases. Crystallographic or microstructural features of these oxides are in 0.3-2 nm size range, so that oxide phonons can efficiently interact with them. We explore in our experiments the effects of doping, grain size, crystallographic defects, superstructures, second phases, texturing and (to a limited extend) processing on electric conductivity, Seebeck coefficient, thermal conductivity and figure of merit. Jonker and lattice-versus-electrical conductivity plots are used to compare specific materials and material families and extract levers for future improvement of oxide thermoelectrics. We show in our work that oxygen vacancy doping (reduction) is a more powerful driver for improving the power factor for SrTiO3, TiO2 and NbO x than heterovalent doping. Based on our Seebeck-conductivity plots, we derived

  1. Stars from the darkest night: unlocking the neurogenic potential of astrocytes in different brain regions.

    PubMed

    Magnusson, Jens P; Frisén, Jonas

    2016-04-01

    In a few regions of the adult brain, specialized astrocytes act as neural stem cells capable of sustaining life-long neurogenesis. In other, typically non-neurogenic regions, some astrocytes have an intrinsic capacity to produce neurons when provoked by particular conditions but do not use this ability to replace neurons completely after injury or disease. Why do astrocytes display regional differences and why do they not use their neurogenic capacity for brain repair to a greater extent? In this Review, we discuss the neurogenic potential of astrocytes in different brain regions and ask what stimulates this potential in some regions but not in others. We discuss the transcriptional networks and environmental cues that govern cell identity, and consider how the activation of neurogenic properties in astrocytes can be understood as the de-repression of a latent neurogenic transcriptional program. PMID:27048686

  2. Damage mechanism at different transpassive potentials of solution-annealed 316 and 316l stainless steels

    NASA Astrophysics Data System (ADS)

    Morshed Behbahani, K.; Pakshir, M.; Abbasi, Z.; Najafisayar, P.

    2015-01-01

    Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI 316 and AISI 316L solution-annealed stainless steels (SS) with different degrees of sensitization. Depending on the DC potential applied during EIS tests, the AC responses in the transpassive region included three different regions: the first one associated with anodic dissolution of the passive layer, the second one contributed to the dissolution at the area near grain boundaries, and the last one attributed to pitting corrosion. In addition, the fitting results to experimental data showed that as the DC bias during the EIS test increases the charge transfer resistance ( R ct) decreases. Moreover, the R ct values decreased as the sensitization temperature increases but the AISI 316L SS samples exhibited a higher resistance to intergranular corrosion than 316 SS samples.

  3. Self-Constrained Euler Deconvolution Using Potential Field Data of Different Altitudes

    NASA Astrophysics Data System (ADS)

    Zhou, Wenna; Nan, Zeyu; Li, Jiyan

    2016-06-01

    Euler deconvolution has been developed as almost the most common tool in potential field data semi-automatic interpretation. The structural index (SI) is a main determining factor of the quality of depth estimation. In this paper, we first present an improved Euler deconvolution method to eliminate the influence of SI using potential field data of different altitudes. The different altitudes data can be obtained by the upward continuation or can be directly obtained by the airborne measurement realization. Euler deconvolution at different altitudes of a certain range has very similar calculation equation. Therefore, the ratio of Euler equations of two different altitudes can be calculated to discard the SI. Thus, the depth and location of geologic source can be directly calculated using the improved Euler deconvolution without any prior information. Particularly, the noise influence can be decreased using the upward continuation of different altitudes. The new method is called self-constrained Euler deconvolution (SED). Subsequently, based on the SED algorithm, we deduce the full tensor gradient (FTG) calculation form of the new improved method. As we all know, using multi-components data of FTG have added advantages in data interpretation. The FTG form is composed by x-, y- and z-directional components. Due to the using more components, the FTG form can get more accurate results and more information in detail. The proposed modification method is tested using different synthetic models, and the satisfactory results are obtained. Finally, we applied the new approach to Bishop model magnetic data and real gravity data. All the results demonstrate that the new approach is utility tool to interpret the potential field and full tensor gradient data.

  4. A test of stress, cues, and re-exposure to large wins as potential reinstaters of suboptimal decision making in rats

    PubMed Central

    Connolly, Nina P.; Kim, Jung S.; Tunstall, Brendan J.; Kearns, David N.

    2015-01-01

    The present experiment investigated potential reinstaters of suboptimal economic decision making in rats. Rats were first trained on a version of the rat Gambling Task under conditions designed to promote choice of a suboptimal option that occasionally resulted in large “wins” (four sucrose pellets). In a second phase, preference for this economically suboptimal option was reduced by substantially increasing the probability of punishment when this option was chosen. Then, three events were tested for their ability to reinstate choice of the suboptimal option. A brief period of re-exposure to a high frequency of large wins significantly increased choice of the suboptimal option. The pharmacological stressor yohimbine did not reinstate suboptimal choice, but did increase impulsive action as indexed by premature responding. Presentation of cues previously associated with large wins did not alter behavior. Results suggest reinstaters of suboptimal choice may differ from reinstaters of extinguished drug- and food-seeking behavior. PMID:25904885

  5. Urinary Bladder-Relaxant Effect of Kurarinone Depending on Potentiation of Large-Conductance Ca2+-Activated K+ Channels.

    PubMed

    Lee, Sojung; Chae, Mee Ree; Lee, Byoung-Cheol; Kim, Yong-Chul; Choi, Jae Sue; Lee, Sung Won; Cheong, Jae Hoon; Park, Chul-Seung

    2016-08-01

    The large-conductance calcium-activated potassium channel (BKCa channel) plays critical roles in smooth muscle relaxation. In urinary bladder smooth muscle, BKCa channel activity underlies the maintenance of the resting membrane potential and repolarization of the spontaneous action potential triggering the phasic contraction. To identify novel BKCa channel activators, we screened a library of natural compounds using a cell-based fluorescence assay and a hyperactive mutant BKCa channel (Lee et al., 2013). From 794 natural compounds, kurarinone, a flavanone from Sophora flavescens, strongly potentiated BKCa channels. When treated from the extracellular side, this compound progressively shifted the conductance-voltage relationship of BKCa channels to more negative voltages and increased the maximum conductance in a dose-dependent manner. Whereas kurarinone strongly potentiated the homomeric BKCa channel composed of only the α subunit, its effects were much smaller on heteromeric channels coassembled with auxiliary β subunits. Although the activation kinetics was not altered significantly, the deactivation of BKCa channels was dramatically slowed by kurarinone treatment. At the single-channel level, kurarinone increased the open probability of the BKCa channel without affecting its single-channel conductance. Kurarinone potently relaxed acetylcholine-induced contraction of rat bladder smooth muscle and thus decreased the micturition frequency of rats with overactive bladder symptoms. These results indicate that kurarinone can directly potentiate BKCa channels and demonstrate the therapeutic potentials of kurarinone and its derivatives for developing antioveractive bladder medications and supplements. PMID:27251362

  6. Generalized energy and potential enstrophy conserving finite difference schemes for the shallow water equations

    NASA Technical Reports Server (NTRS)

    Abramopoulos, Frank

    1988-01-01

    The conditions under which finite difference schemes for the shallow water equations can conserve both total energy and potential enstrophy are considered. A method of deriving such schemes using operator formalism is developed. Several such schemes are derived for the A-, B- and C-grids. The derived schemes include second-order schemes and pseudo-fourth-order schemes. The simplest B-grid pseudo-fourth-order schemes are presented.

  7. Determination of the electrostatic potential difference between DNA and the solution containing it: A kinetic approach

    NASA Astrophysics Data System (ADS)

    Carrasco, Mario; Coca, Raquel; Cruz, Isabel; Daza, Silvia; Espina, Manuela; Garcia-Fernandez, Emilio; Guerra, Francisco J.; León, Rafael; Marchena, María J.; Pérez, Inmaculada; Puente, Manuel; Suárez, Esteban; Valencia, Inmaculada; Villalba, Inmaculada; Jiménez, Rafael

    2007-06-01

    A kinetic approach to determine the electrostatic potential difference in soft interfaces, when classical methods fail, is presented. The method is based on electrostatic and non-electrostatic separation of the binding constant of one reactant to one of the phases. Here the method is applied to the DNA/water interface. Reliable results are obtained using as probes the reactions [Ru(NH)5pz]+SO82- and [Co(NH 3) 5pz] 3+ + [Fe(CN) 6] 4-.

  8. Optical Emission Spectroscopic Evaluation of Different Microwave Plasma Discharges and Its Potential Application for Sterilization Processes

    NASA Astrophysics Data System (ADS)

    Hueso, José L.; Rico, Víctor J.; Yanguas-Gil, Ángel; Cotrino, José; González-Elipe, Agustín R.

    The present work aims at studying different microwave flowing discharges containing Ar and/or NO as alternative candidates to more extended N2 containing plasma mixtures like N2-O2. Optical Emission Spectroscopy (OES) is used to demonstrate the potential possibilities of these plasma mixtures to provide O* and UV intermediate species demanded for sterilization purposes at low temperatures and extended discharge gaps. Additionally, some plasma sterilization experiments with Escherichia coli cultures are presented.

  9. Effect of Different Tube Potential Settings on Caries Detection using PSP Plate and Conventional Film

    PubMed Central

    Cruz, Adriana Dibo; Melo, Saulo Leonardo Sousa; De Farias, Julyanna Filgueiras GonçAlves; Haiter-Neto, Francisco; De Almeida, Solange Maria

    2015-01-01

    Purpose To compare intraoral Phosphor Stimulable Plate digital system and intraoral film using different tube settings on incipient proximal caries detection. Materials and Methods Five blocks, with five teeth each, were radiographically examined using phosphor plates and F-speed films. The images were acquired in 07 different tube potentials from 50-80 kV. The films were digitized. Three oral radiologists scored the images for the presence of caries using a 5-point rating scale. The areas under ROC curve were calculated. The influence of tube kilovoltage was verified by ANOVA and pair wise comparisons performed using Tukey test. Results Mean ROC curve areas varied from 0.446-0.628 for digital images and 0.494–0.559 for conventional images. The tube setting of 70 kV presented the best result both for digital and conventional images. Considering the image type separately, 70 kV scored highest followed by 75 and 65 kV for digital images (p=0.084). For conventional image modality, even though 70 kV presented the best result, it did not differ significantly from 80 kV, not differing from 60 and 55 kV, which did not differ from 75, 65 and 50 kV (p=0.53). Conclusion Phosphor plate digital images seem to be more susceptible to tube setting potential variations then digitized film images. PMID:26023645

  10. Evidence for a difference in rupture initiation between small and large earthquakes.

    PubMed

    Colombelli, S; Zollo, A; Festa, G; Picozzi, M

    2014-01-01

    The process of earthquake rupture nucleation and propagation has been investigated through laboratory experiments and theoretical modelling, but a limited number of observations exist at the scale of earthquake fault zones. Distinct models have been proposed, and whether the magnitude can be predicted while the rupture is ongoing represents an unsolved question. Here we show that the evolution of P-wave peak displacement with time is informative regarding the early stage of the rupture process and can be used as a proxy for the final size of the rupture. For the analysed earthquake set, we found a rapid initial increase of the peak displacement for small events and a slower growth for large earthquakes. Our results indicate that earthquakes occurring in a region with a large critical slip distance have a greater likelihood of growing into a large rupture than those originating in a region with a smaller slip-weakening distance. PMID:24887597

  11. Frequency spectrum of transepithelial potential difference reveals transport-related oscillations.

    PubMed

    Montalbetti, Nicolás; Fischbarg, Jorge

    2009-09-16

    How epithelia transport fluid is a fundamental issue that is unresolved. Explanations offered include molecular engines, local transcellular osmosis, local paracellular osmosis, and paracellular fluid transport. On the basis of experimental and theoretical work done on corneal endothelium, a fluid transporting epithelium, we suggest electroosmotic coupling at the level of the intercellular junctions driven by the transendothelial electrical potential difference as an explanation of paracellular fluid transport. We collect frequency spectra of that potential difference in real-time. For what we believe is the first time for any epithelium, we report that, unexpectedly, the potential difference displays oscillations at many characteristic frequencies. We also show that on both stimulating cell activity and inhibiting ion transport mechanisms, there are corresponding changes in the oscillations amplitudes that mirror changes known previously in rates of fluid transport. We believe these findings provide a novel tool to study the kinetics of electrogenic elements such as channels and transporters, which from this evidence would give rise to current oscillations with characteristic periods going from 150 ms to 8 s. PMID:19751657

  12. Exercise Bouts at Three Different Intensities Fail to Potentiate Concentric Power

    PubMed Central

    CABRERA, CHAD A.; MORALES, JACOBO; GREER, FELICIA; PETTITT, ROBERT W.

    2009-01-01

    Postactivation potentiation (PAP) has been hypothesized previously to occur during voluntary, concentric actions. We tested the hypothesis that one of at least three different intensities of conditioning exercises would evoke potentiation of power during the concentric, bench press throw (BPT). Twelve men (age = 22.9 ± 2.7 years, bench press 1 repetition maximum (1RM) = 1.20 ± 0.12 kg·kg−1 body weight) completed five isotonic conditioning presses at ~55, 70, and 86% 1RM, in counterbalanced order, and on separate days. Average and peak power of the BPT using a load of 55% 1RM along with surface electromyography (EMG) of the triceps brachii were collected prior to and 4-minutes following each conditioning bout. Both average and peak power and EMG values (mean ± SD), respectively, were evaluated using two-way analyses of variance with repeated measures. Significant main effect decreases (p < 0.05) in average (−18.6 ± 4.9 W) and peak power (−37.4 ± 9.9 W) occurred across the three different intensities evaluated. No main effects or interactions were observed with the EMG data. Contrary to the previously reported hypothesis, we were unable to demonstrate that conditioning exercise, with three different intensities, can evoke potentiation of power using a load equating to that which is optimum for power production. PMID:27182310

  13. Comparative study of the osteogenic ability of four different ceramic constructs in an ectopic large animal model.

    PubMed

    Viateau, Véronique; Manassero, Mathieu; Sensébé, Luc; Langonné, Alain; Marchat, David; Logeart-Avramoglou, Delphine; Petite, Hervé; Bensidhoum, Morad

    2016-03-01

    Tissue-engineered constructs combining bone marrow mesenchymal stem cells with biodegradable osteoconductive scaffolds are very promising for repairing large segmental bone defects. Synchronizing and controlling the balance between scaffold-material resorption and new bone tissue formation are crucial aspects for the success of bone tissue engineering. The purpose of the present study was to determine, and compare, the osteogenic potential of ceramic scaffolds with different resorbability. Four clinically relevant granular biomaterial scaffolds (specifically, Porites coral, Acropora coral, beta-tricalcium phosphate and banked bone) with or without autologous bone marrow stromal cells were implanted in the ectopic, subcutaneous-pouch sheep model. Scaffold material resorption and new bone formation were assessed eight weeks after implantation. New bone formation was only detected when the biomaterial constructs tested contained MSCs. New bone formation was higher in the Porites coral and Acropora coral than in either the beta-tricalcium phosphate or the banked bone constructs; furthermore, there was a direct correlation between scaffold resorption and bone formation. The results of the present study provide evidence that, among the biomaterials tested, coral scaffolds containing MSCs promoted the best new bone formation in the present study. PMID:23784976

  14. Hydrodynamic modeling of juvenile mussel dispersal in a large river: The potential effects of bed shear stress and other parameters

    USGS Publications Warehouse

    Daraio, J.A.; Weber, L.J.; Newton, T.J.

    2010-01-01

    Because unionid mussels have a parasitic larval stage, they are able to disperse upstream and downstream as larvae while attached to their host fish and with flow as juveniles after excystment from the host. Understanding unionid population ecology requires knowledge of the processes that affect juvenile dispersal prior to establishment. We examined presettlement (transport and dispersion with flow) and early postsettlement (bed shear stress) hydraulic processes as negative censoring mechanisms. Our approach was to model dispersal using particle tracking through a 3-dimensional flow field output from hydrodynamic models of a reach of the Upper Mississippi River. We tested the potential effects of bed shear stress (??b) at 5 flow rates on juvenile mussel dispersal and quantified the magnitude of these effects as a function of flow rate. We explored the reach-scale relationships of Froude number (Fr), water depth (H), local bed slope (S), and unit stream power (QS) with the likelihood of juvenile settling (??). We ran multiple dispersal simulations at each flow rate to estimate ??, the parameter of a Poisson distribution, from the number of juveniles settling in each grid cell, and calculated dispersal distances. Virtual juveniles that settled in areas of the river where b > critical shear stress (c) were resuspended in the flow and transported further downstream, so we ran simulations at 3 different conditions for ??c (??c = ??? no resuspension, 0.1, and 0.05 N/m2). Differences in virtual juvenile dispersal distance were significantly dependent upon c and flow rate, and effects of b on settling distribution were dependent upon c. Most simulations resulted in positive correlations between ?? and ??b, results suggesting that during early postsettlement, ??b might be the primary determinant of juvenile settling distribution. Negative correlations between ?? and ??b occurred in some simulations, a result suggesting that physical or biological presettlement processes

  15. Potential vertical movement of large heat-generating waste packages in salt.

    SciTech Connect

    Clayton, Daniel James; Martinez, Mario J.; Hardin, Ernest L.

    2013-05-01

    With renewed interest in disposal of heat-generating waste in bedded or domal salt formations, scoping analyses were conducted to estimate rates of waste package vertical movement. Vertical movement is found to result from thermal expansion, from upward creep or heave of the near-field salt, and from downward buoyant forces on the waste package. A two-pronged analysis approach was used, with thermal-mechanical creep modeling, and coupled thermal-viscous flow modeling. The thermal-mechanical approach used well-studied salt constitutive models, while the thermal-viscous approach represented the salt as a highly viscous fluid. The Sierra suite of coupled simulation codes was used for both approaches. The waste package in all simulations was a right-circular cylinder with the density of steel, in horizontal orientation. A time-decaying heat generation function was used to represent commercial spent fuel with typical burnup and 50-year age. Results from the thermal-mechanical base case showed approximately 27 cm initial uplift of the package, followed by gradual relaxation closely following the calculated temperature history. A similar displacement history was obtained with the package density set equal to that of salt. The slight difference in these runs is attributable to buoyant displacement (sinking) and is on the order of 1 mm in 2,000 years. Without heat generation the displacement stabilizes at a fraction of millimeter after a few hundred years. Results from thermal-viscous model were similar, except that the rate of sinking was constant after cooldown, at approximately 0.15 mm per 1,000 yr. In summary, all calculations showed vertical movement on the order of 1 mm or less in 2,000 yr, including calculations using well-established constitutive models for temperature-dependent salt deformation. Based on this finding, displacement of waste packages in a salt repository is not a significant repository performance issue.

  16. Osmotic Dependence of the Transmembrane Potential Difference of Broadbean Mesocarp Cells 1

    PubMed Central

    Li, Ze-Sheng; Delrot, Serge

    1987-01-01

    Pod walls of broadbean (Vicia faba L. cv Aguadulce) were harvested at the import (S1), at the transition (S2) or at the export (S3) phase for assimilate transport. Measurements of the transmembrane potential difference (PD) of mesocarp cells were made under various osmotic conditions. Internal osmotic potentials and cell turgor were calculated from osmolality measurements of cell saps recovered by freeze-thawing, after correction for the contribution of the free-space solution. Changes in the mannitol concentration of the medium altered the PD within a few minutes, and new stable values of PD were reached within 20 minutes after the osmotic change. With mannitol as the osmoticum, the most negative PD was measured at an external osmotic potential of -0.70 megapascals (MPa) for S1 and S2, while the most negative was at -0.40 MPa for S3. Ethylene glycol, a permeant osmoticum, had little effect on PD, showing that the PD was sensitive to turgor, not to solute potential per se. For S1 and S2, the PD was less negative for turgor potentials lower than 0.1 MPa or greater than 0.3 MPa. S3 samples exhibited a different turgor dependence, with a sharp optimum of the negativity of the PD at 0.3 MPa. The data are consistent with the proposal that the proton pump acts as a transducer of the osmotic conditions. They show that the osmotic sensitivity of the PD of mesocarp cells of broadbean changes with the stage of development of the pod. PMID:16665540

  17. Examination of Sex Differences in a Large Sample of Young Children with Autism Spectrum Disorder and Typical Development

    ERIC Educational Resources Information Center

    Reinhardt, Vanessa P.; Wetherby, Amy M.; Schatschneider, Christopher; Lord, Catherine

    2015-01-01

    Despite consistent and substantive research documenting a large male to female ratio in Autism Spectrum Disorder (ASD), only a modest body of research exists examining sex differences in characteristics. This study examined sex differences in developmental functioning and early social communication in children with ASD as compared to children with…

  18. 25 CFR 900.220 - Does it make a difference whether the claim is large or small?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Does it make a difference whether the claim is large or small? 900.220 Section 900.220 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR, AND INDIAN... EDUCATION ASSISTANCE ACT Post-Award Contract Disputes § 900.220 Does it make a difference whether the...

  19. Potential Mechanisms for Racial and Ethnic Differences in Antimüllerian Hormone and Ovarian Reserve

    PubMed Central

    Seifer, David B.

    2013-01-01

    Accumulating evidence suggests that reproductive potential and function may be different across racial and ethnic groups. Racial differences have been demonstrated in pubertal timing, infertility, outcomes after assisted reproductive technology (ART) treatment, and reproductive aging. Recently, racial differences have also been described in serum antimüllerian hormone (AMH), a sensitive biomarker of ovarian reserve, supporting the notion that ovarian reserve differs between racial/ethnic groups. The existence of such racial/ethnic differences in ovarian reserve, as reflected by AMH, may have important clinical implications for reproductive endocrinologists. However, the mechanisms which may underlie such racial differences in ovarian reserve are unclear. Various genetic factors and environmental factors such as obesity, smoking, and vitamin D deficiency which have been shown to correlate with serum AMH levels and also display significant racial/ethnic variations are discussed in this review. Improving our understanding of racial differences in ovarian reserve and their underlying causes may be essential for infertility treatment in minority women and lead to better reproductive planning, improved treatment outcomes, and timely interventions which may prolong reproductive lifespan in these women. PMID:24348557

  20. Auditory Evoked Potentials with Different Speech Stimuli: a Comparison and Standardization of Values

    PubMed Central

    Didoné, Dayane Domeneghini; Oppitz, Sheila Jacques; Folgearini, Jordana; Biaggio, Eliara Pinto Vieira; Garcia, Michele Vargas

    2016-01-01

    Introduction Long Latency Auditory Evoked Potentials (LLAEP) with speech sounds has been the subject of research, as these stimuli would be ideal to check individualś detection and discrimination. Objective The objective of this study is to compare and describe the values of latency and amplitude of cortical potentials for speech stimuli in adults with normal hearing. Methods The sample population included 30 normal hearing individuals aged between 18 and 32 years old with ontological disease and auditory processing. All participants underwent LLAEP search using pairs of speech stimuli (/ba/ x /ga/, /ba/ x /da/, and /ba/ x /di/. The authors studied the LLAEP using binaural stimuli at an intensity of 75dBNPS. In total, they used 300 stimuli were used (∼60 rare and 240 frequent) to obtain the LLAEP. Individuals received guidance to count the rare stimuli. The authors analyzed latencies of potential P1, N1, P2, N2, and P300, as well as the ampleness of P300. Results The mean age of the group was approximately 23 years. The averages of cortical potentials vary according to different speech stimuli. The N2 latency was greater for /ba/ x /di/ and P300 latency was greater for /ba/ x /ga/. Considering the overall average amplitude, it ranged from 5.35 and 7.35uV for different speech stimuli. Conclusion It was possible to obtain the values of latency and amplitude for different speech stimuli. Furthermore, the N2 component showed higher latency with the / ba / x / di / stimulus and P300 for /ba/ x / ga /. PMID:27096012

  1. Membrane potential difference and intracellular cation concentrations in human placental trophoblast cells in culture.

    PubMed Central

    Greenwood, S L; Clarson, L H; Sides, M K; Sibley, C P

    1996-01-01

    1. The electrochemical gradients for Na+ and K+ were assessed in a cell culture model of trophoblast differentiation. 2. Membrane potential difference (Em), intracellular water and Na+ and K+ contents were measured in choriocarcinoma cells (JAr cell line; 96% of which are undifferentiated trophoblast cells) and in mononucleate and multinucleate (differentiated) cytotrophoblast cells isolated from the human placenta at term. 3. There was a significant fall in Em from -57 mV in JAr cells, to -48 and -40 mV in mono-and multinucleate cytotrophoblast cells, respectively. Treatment with ouabain (1 mM for 15 min) depolarized the JAr cell membrane by 15 mV but did not affect cytotrophoblast cell membrane potential. 4. Intracellular K+ concentration was similar in JAr, mono- and multinucleate cytotrophoblast cells but Na+ concentration was higher in mononucleate cytotrophoblast cells compared with JAr cells. 5. Ouabain treatment (3 mM for 15 min) caused a small increase (4.5%) in cell water in mononucleate cytotrophoblast cells but lowered K+ (approximately 30%) and increased Na+ concentration (approximately 125%) in all the trophoblast cells studied. 6. The K+ equilibrium potential (EK) was more negative than Em in all cells and the difference between EK and Em was smaller in JAr cells (-25 mV) than in mono- and multinucleate cytotrophoblast cells (-33 and -43 mV, respectively). 7. The Na+ equilibrium potential (ENa) was positive in the trophoblast cells and the difference between ENa and Em was 122, 100 and 100 mV in JAr, mono- and multinucleate cytotrophoblast cells, respectively. 8. These results suggest that the electrochemical gradient for K+ is affected by the stage of trophoblast cell differentiation. In contrast, the electrochemical gradient for Na+ is similar in mono- and multinucleate cytotrophoblast cells. Images Figure 1 PMID:8734977

  2. Differences in PAR-2 activating potential by king crab (Paralithodes camtschaticus), salmon (Salmo salar), and bovine (Bos taurus) trypsin

    PubMed Central

    2013-01-01

    Background Salmon trypsin is shown to increase secretion of the pro-inflammatory cytokine interleukin (IL)-8 from human airway epithelial cells through activation of PAR-2. Secretion of IL-8 induced by king crab trypsin is observed in a different concentration range compared to salmon trypsin, and seems to be only partially related to PAR-2 activation. This report aim to identify differences in the molecular structure of king crab trypsin (Paralithodes camtschaticus) compared to salmon (Salmo salar) and bovine trypsin (Bos taurus) that might influence the ability to activate protease-activated receptor-2 (PAR-2). Results During purification king crab trypsin displayed stronger binding capacity to the anionic column used in fast protein liquid chromatography compared to fish trypsins, and was identified as a slightly bigger molecule. Measurements of enzymatic activity yielded no obvious differences between the trypsins tested. Molecular modelling showed that king crab trypsin has a large area with strong negative electrostatic potential compared to the smaller negative areas in bovine and salmon trypsins. Bovine and salmon trypsins also displayed areas with strong positive electrostatic potential, a feature lacking in the king crab trypsin. Furthermore we have identified 3 divergent positions (Asp196, Arg244, and Tyr247) located near the substrate binding pocket of king crab trypsin that might affect the binding and cleavage of PAR-2. Conclusion These preliminary results indicate that electrostatic interactions could be of importance in binding, cleavage and subsequent activation of PAR-2. PMID:23870109

  3. Analysis of 6Li Scattering at 240 MeV Using Different Nuclear Potentials

    NASA Astrophysics Data System (ADS)

    Al-Ghamdi, A. H.; Ibraheem, Awad A.

    2016-06-01

    Angular distributions of the elastic and inelastic scattering cross sections of 6Li projectile on different heavy ion target nuclei including the 24Mg, 28Si, 48Ca, 58Ni, 90Zr, and 116Sn at energy of 240 MeV have been analyzed by using two different folded potentials based on the CDM3Y6 and São Paulo potentials for the real part of the optical potential, while the imaginary parts have a phenomenological Woods-Saxon shape. Coupled channel calculations for the low-lying 2+ state at 1.369, 1.779, 3.832, 1.454, 2.186, and 1.29 MeV for 24Mg, 28Si, 48Ca, 58Ni, 90Zr, and 116Sn, respectively, have been carried out, and the best fit values for B(EL) with the above models have been extracted by fitting the inelastic scattering cross section and compared with the values of previous works. The total reaction cross section and real and imaginary volume integrals have also been investigated.

  4. Environmental assessment of two different crop systems in terms of biomethane potential production.

    PubMed

    Bacenetti, Jacopo; Fusi, Alessandra; Negri, Marco; Guidetti, Riccardo; Fiala, Marco

    2014-01-01

    The interest in renewable energy sources has gained great importance in Europe due to the need to reduce fossil energy consumption and greenhouse gas emissions, as required by the Renewable Energy Directive (RED) of the European Parliament. The production of energy from energy crops appears to be consistent with RED. The environmental impact related to this kind of energy primarily originates from crop cultivation. This research aimed to evaluate the environmental impact of different crop systems for biomass production: single and double crop. The environmental performances of maize and maize plus wheat were assessed from a life cycle perspective. Two alternative scenarios considering different yields, crop management, and climatic conditions, were also addressed. One normal cubic metre of potential methane was chosen as a functional unit. Methane potential production data were obtained through lab experimental tests. For both of the crop systems, the factors that have the greatest influence on the overall environmental burden are: fertilizer emissions, diesel fuel emissions, diesel fuel production, and pesticide production. Notwithstanding the greater level of methane potential production, the double crop system appears to have the worse environmental performance with respect to its single crop counterpart. This result is due to the bigger quantity of inputs needed for the double crop system. Therefore, the greater amount of biomass (silage) obtained through the double crop system is less than proportional to the environmental burden that results from the bigger quantity of inputs requested for double crop. PMID:23994820

  5. Sex Differences in Autism Spectrum Disorder: Evidence from a Large Sample of Children and Adolescents

    ERIC Educational Resources Information Center

    Mandy, William; Chilvers, Rebecca; Chowdhury, Uttom; Salter, Gemma; Seigal, Anna; Skuse, David

    2012-01-01

    Sex differences have been found amongst toddlers and young children with autism spectrum disorder (ASD). We investigated the presence and stability of these ASD sex differences throughout childhood and adolescence. Participants (N = 325, 52 females; aged 3-18 years) consecutively received an ASD diagnosis at a clinic for assessing high-functioning…

  6. Influence of different deposition potential on the structural and optical properties of copper selenide nanowires

    NASA Astrophysics Data System (ADS)

    Kaur, Harmanmeet; Kaur, Jaskiran; Singh, Lakhwant

    2016-09-01

    In this paper, nanowires were successfully fabricated from the aqueous solution containing 0.2 M/l CuSO4.5H2O, 0.1 M/l SeO2, 1 g/l PVP and a few drops of H2SO4 in Milli-Q water using electrodeposition technique at room temperature. Influence of different deposition potential on structural and optical properties of copper selenide nanowires has been investigated here. Morphological, structural and optical properties were monitored through field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and UV-visible 1800 spectrophotometer. From the XRD analysis, it was found that the stoichiometric (CuSe) nanowires are formed at deposition potential (-0.6 V) and (+0.6 V). Band gap of nanowires were found to be maximum around 3.13 eV for deposition potential (-0.8 V) and minimum of 2.81 eV for deposition potential (-0.6 V).

  7. Extinction of radiant energy by large atmospheric crystals with different shapes

    NASA Astrophysics Data System (ADS)

    Shefer, Olga

    2016-07-01

    The calculated results of extinction characteristics of visible and infrared radiation for large semi-transparent crystals are obtained by hybrid technique, which is a combination of the geometric optics method and the physical optics method. Energy and polarization characteristics of the radiation extinction in terms of the elements of the extinction matrix for individual large crystals and ensemble of crystals are discussed. Influences of particle shapes, aspect ratios, parameters of size distribution, complex refractive index, orientation of crystals, wavelength, and the polarization state of an incident radiation on the extinction are illustrated. It is shown that the most expressive and stable features of energy and polarization characteristics of the extinction are observed in the midinfrared region, despite the fact that the ice particles significantly absorb the radiant energy of this spectrum. It is demonstrated that the polarized extinction characteristics can reach several tens of percent at IR wavelengths. For the large crystals, the conditions of occurrence of the spectral behavior of the extinction coefficient in the visible, near-IR, and mid-IR wavelength ranges are determined.

  8. Myoelectric activity along human gastrocnemius medialis: different spatial distributions of postural and electrically elicited surface potentials.

    PubMed

    Hodson-Tole, Emma F; Loram, Ian D; Vieira, Taian M M

    2013-02-01

    It has recently been shown that motor units in human medial gastrocnemius (MG), activated during standing, occupy relatively small territories along the muscle's longitudinal axis. Such organisation provides potential for different motor tasks to produce differing regional patterns of activity. Here, we investigate whether postural control and nerve electrical stimulation produce equal longitudinal activation patterns in MG. Myoelectric activity, at different proximal-distal locations of MG, was recorded using a linear electrode array. To ensure differences in signal amplitude between channels did not result from local, morphological factors two experimental protocols were completed: (i) quiet standing; (ii) electrical stimulation of the tibial nerve. Averaged, rectified values (ARVs) were calculated for each channel in each condition. The distribution of signals along electrode channels was described using linear regression and differences between protocols at each channel determined as the ratio between mean ARV from standing: stimulation protocols. Ratio values changed systematically across electrode channels in seven (of eight) participants, with larger values in distal channels. The distribution of ARV along MG therefore differed between experimental conditions. Compared to fibres of units activated during MG nerve stimulation, units activated during standing may have a tendency to be more highly represented in the distal muscle portion. PMID:22967836

  9. Evaluation of the mutagenic potential of different forms of energy production.

    PubMed

    Léonard, A; Léonard, E D

    1983-08-01

    The consequence of exposure to the effluents of power plants that elicits the most concern is probably the induction of cancers. Due mainly to the high uncertainty of epidemiological surveys on exposure to low doses of mutagens, observations performed up to now on man have provided contradictory and inconclusive results. Since a high correlation exists between the mutagenicity of environmental agents and their carcinogenic properties, an attempt has been made to evaluate the carcinogenic potential of the different forms of energy production on the basis of the results of short term tests performed on the effluents of several power plants. Any energy source is associated with such risks and, in spite of the fact that real comparative studies were not available, coal as a source of energy presents obviously higher mutagenic potential than nuclear power. Renewable forms of energy are cleaner but are, however, not entirely devoid of health impacts. PMID:6356352

  10. Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning

    PubMed Central

    Mouly, Anne Marie; Gervais, Rémi

    2002-01-01

    This study was aimed at investigating the consequences of learning on late polysynaptic components of evoked field potential signals recorded in parallel at different levels of the olfactory pathways. For this, evoked field potentials induced by electrical stimulation of the olfactory bulb were recorded simultaneously in the anterior piriform cortex, the posterior piriform cortex, the lateral entorhinal cortex, and the dentate gyrus. The different parameters of late components were measured in each site before and after completion of associative learning in anesthetized rats. In the learning task, rats were trained to associate electrical stimulation of one olfactory bulb electrode with the delivery of sucrose (positive reward) and stimulation of a second olfactory bulb electrode with the delivery of quinine (negative reward). In this way, stimulation of the same olfactory bulb electrodes used for inducing field potentials served as a discriminative cue in the learning paradigm. The data confirmed previous observation that learning was associated with a lowering in late-component-1 intensity of induction in the posterior piriform cortex. The use of simultaneous recording allowed us to further specify the consequences of learning on late-component distribution in the studied network. Indeed the data showed that whereas before learning, late component 1 was rather uniformly distributed among the recorded sites; following learning, its expression was facilitated preferentially in the posterior piriform cortex and lateral entorhinal cortex. Furthermore, learning was accompanied by the emergence of a new late component (late component 2), which occurred simultaneously in the four recording sites. The possible involvement of potentiation of polysynaptic components in recognition and/or consolidation processes will be discussed. PMID:11992017

  11. Comparing large scale CCS deployment potential in the USA and China: a detailed analysis based on country-specific CO2 transport & storage cost curves

    SciTech Connect

    Dahowski, Robert T.; Davidson, Casie L.; Dooley, James J.

    2011-04-18

    The United States and China are the two largest emitters of greenhouse gases in the world and their projected continued growth and reliance on fossil fuels, especially coal, make them strong candidates for CCS. Previous work has revealed that both nations have over 1600 large electric utility and other industrial point CO2 sources as well as very large CO2 storage resources on the order of 2,000 billion metric tons (Gt) of onshore storage capacity. In each case, the vast majority of this capacity is found in deep saline formations. In both the USA and China, candidate storage reservoirs are likely to be accessible by most sources with over 80% of these large industrial CO2 sources having a CO2 storage option within just 80 km. This suggests a strong potential for CCS deployment as a meaningful option to efforts to reduce CO2 emissions from these large, vibrant economies. However, while the USA and China possess many similarities with regards to the potential value that CCS might provide, including the range of costs at which CCS may be available to most large CO2 sources in each nation, there are a number of more subtle differences that may help us to understand the ways in which CCS deployment may differ between these two countries in order for the USA and China to work together - and in step with the rest of the world - to most efficiently reduce greenhouse gas emissions. This paper details the first ever analysis of CCS deployment costs in these two countries based on methodologically comparable CO2 source and sink inventories, economic analysis, geospatial source-sink matching and cost curve modeling. This type of analysis provides a valuable insight into the degree to which early and sustained opportunities for climate change mitigation via commercial-scale CCS are available to the two countries, and could facilitate greater collaboration in areas where those opportunities overlap.

  12. Potential of a Future Large Aperture UVOIR Space Observatory for Breakthrough Observations of Star and Planet Formation

    NASA Astrophysics Data System (ADS)

    Danchi, William C.; Grady, Carol A.; Padgett, Deborah

    2015-01-01

    A future large aperture space observatory operating from the UV to the near-infrared with a diameter between 10 and 15 meters will provide a unique opportunity for observations of star and planet formation, from nearby moving groups and associations to star formation in galaxies in the local universe. Our newly formed working group will examine the unique opportunities that such a telescope will give observers in a post-JWST/WFIRST-AFTA era that includes extremely large ground-based observatories such as the TMT, E-ELT, ALMA, and the VLTI. Given a potential suite of instruments for this observatory we will discuss some of the key areas of star and planet formation science where breakthroughs might occur.

  13. Paranormal psychic believers and skeptics: a large-scale test of the cognitive differences hypothesis.

    PubMed

    Gray, Stephen J; Gallo, David A

    2016-02-01

    Belief in paranormal psychic phenomena is widespread in the United States, with over a third of the population believing in extrasensory perception (ESP). Why do some people believe, while others are skeptical? According to the cognitive differences hypothesis, individual differences in the way people process information about the world can contribute to the creation of psychic beliefs, such as differences in memory accuracy (e.g., selectively remembering a fortune teller's correct predictions) or analytical thinking (e.g., relying on intuition rather than scrutinizing evidence). While this hypothesis is prevalent in the literature, few have attempted to empirically test it. Here, we provided the most comprehensive test of the cognitive differences hypothesis to date. In 3 studies, we used online screening to recruit groups of strong believers and strong skeptics, matched on key demographics (age, sex, and years of education). These groups were then tested in laboratory and online settings using multiple cognitive tasks and other measures. Our cognitive testing showed that there were no consistent group differences on tasks of episodic memory distortion, autobiographical memory distortion, or working memory capacity, but skeptics consistently outperformed believers on several tasks tapping analytical or logical thinking as well as vocabulary. These findings demonstrate cognitive similarities and differences between these groups and suggest that differences in analytical thinking and conceptual knowledge might contribute to the development of psychic beliefs. We also found that psychic belief was associated with greater life satisfaction, demonstrating benefits associated with psychic beliefs and highlighting the role of both cognitive and noncognitive factors in understanding these individual differences. PMID:26503412

  14. Large impact crater histories of Mars: The effect of different model crater age techniques

    NASA Astrophysics Data System (ADS)

    Robbins, Stuart J.; Hynek, Brian M.; Lillis, Robert J.; Bottke, William F.

    2013-07-01

    Impact events that produce large craters primarily occurred early in the Solar System's history because the largest bolides were remnants from planetary formation. Determining when large impacts occurred on a planetary surface such as Mars can yield clues to the flux of material in the early inner Solar System which, in turn, can constrain other planetary processes such as the timing and magnitude of resurfacing and the history of the martian core dynamo. We have used a large, global planetary database in conjunction with geomorphologic mapping to identify craters superposed on the rims of 78 larger craters with diameters D ⩾ 150 km on Mars, ≈78% of which have not been previously dated in this manner. The densities of superposed craters with diameters larger than 10, 16, 25, and 50 km, as well as isochron fits were used to derive model crater ages of these larger craters and basins from which we derived an impact flux. In discussing these ages, we point out several internal inconsistencies of crater-age modeling techniques and chronology systems and, all told, we explain why we think isochron-fitting is the most reliable indicator of an age. Our results point to a mostly obliterated crater record prior to ˜4.0 Ga with the oldest preserved mappable craters on Mars dating to ˜4.3-4.35 Ga. We have used our results to constrain the cessation time of the martian core dynamo which we found to have occurred between the formation of Ladon and Prometheus basins, approximately 4.06-4.09 Ga. We also show that, overall, surfaces on Mars older than ˜4.0-4.1 Ga have experienced >1 km of resurfacing, while those younger than ˜3.8-3.9 Ga have experienced significantly less.

  15. Plant community response to loss of large herbivores differs between North American and South African savanna grasslands.

    PubMed

    Koerner, Sally E; Burkepile, Deron E; Fynn, Richard W S; Burns, Catherine E; Eby, Stephanie; Govender, Navashni; Hagenah, Nicole; Matchett, Katherine J; Thompson, Dave I; Wilcox, Kevin R; Collins, Scott L; Kirkman, Kevin P; Knapp, Alan K; Smith, Melinda D

    2014-04-01

    Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). We hypothesized that the removal of a single grass-feeding herbivore from Konza would decrease plant community richness and shift community composition due to increased dominance by grasses. Similarly, we expected grass dominance to increase at Kruger when removing large herbivores, but because large herbivores are more diverse, targeting both grasses and forbs, at this study site, the changes due to herbivore removal would be muted. After seven years of large-herbivore exclusion, richness strongly decreased and community composition changed at Konza, whereas little change was evident at Kruger. We found that this divergence in response was largely due to differences in the traits and numbers of dominant grasses between the study sites rather than the predicted differences in herbivore assemblages. Thus, the diversity of large herbivores lost may be less important in determining plant community dynamics than the functional traits of the grasses that dominate mesic, disturbance-maintained savanna grasslands. PMID:24933802

  16. What causes the difference in synergistic potentials of propiconazole and prochloraz toward pyrethroids in Daphnia magna?

    PubMed

    Dalhoff, Kristoffer; Gottardi, Michele; Kretschmann, Andreas; Cedergreen, Nina

    2016-03-01

    Azole fungicides (imidazoles and triazoles) are known to function synergistically with several compounds, especially with pyrethroid insecticides, most likely by inhibiting cytochrome P450. Different azole fungicides have been shown to differ in their synergistic potentials usually with the imidazoles being stronger synergists than the triazoles. This study investigated whether the toxicokinetic and toxicodynamic (TKTD) properties of the imidazole prochloraz and triazole propiconazole can explain their different synergistic potential toward the freshwater macroinvertebrate Daphnia magna. Pulse exposure to external concentrations of propiconazole (1.4μM) and prochloraz (1.7μM) for 18h resulted in internal concentrations of 22.7 and 53.5μmolkg(-1)w.w. for propiconazole and prochloraz, respectively. This 2-fold difference in bioaccumulation corresponded very well with the observed 2.7-fold lower external EC50-estimate (7 days) for prochloraz compared to propiconazole. The estimated IC50 for the in vivo inhibition of cytochrome P450 (ECOD) activity, however, measured as transformation of 7-ethoxycoumarin into 7-hydroxycoumarin, was almost 500-fold higher for prochloraz (IC50: 0.011±0.002μM) compared to propiconazole (IC50: 4.9±0.06μM). When indirectly measuring the binding strength of the two azoles, daphnids exposed to propiconazole recovered roughly 80% of their ECOD activity compared to the control shortly after being moved to azole-free medium, indicating that propiconazole causes reversible inhibition of cytochrome P450. In contrast, the ECOD-activity remained inhibited in the prochloraz-exposed daphnids for 12h following transfer to azole-free medium, which correlated with elimination of the measured internal prochloraz concentration (DT95≈13h). These results indicate that lethal toxicity of the azole fungicides is mainly driven by toxicokinetics through their hydrophobicities resulting in different internal concentrations. Their synergistic potential

  17. Phytoremediation potential of cadmium-contaminated soil by Eucalyptus globulus under different coppice systems.

    PubMed

    Luo, Jie; Qi, Shihua; Peng, Li; Xie, Xianming

    2015-03-01

    The objective of this research was to determine the phytoremediation potential of Eucalyptus globulus in Cd contaminated soil through two different harvest methods. Although replanting is more expensive than coppicing and produces less aboveground biomass, more Cd can be removed from the soil with roots removal at each harvest as the E. globulus absorbs vast majority of heavy metals in non-metabolically active parts like roots. Despite the higher cost of replanting in a single harvest, when phytoremediation efficiency and total duration are considered as important factors, the replanting treatment should be recommended as an appropriate method which can decrease the phytoremediation time obviously. PMID:25543544

  18. Finite-difference simulation of transonic separated flow using a full potential boundary layer interaction approach

    NASA Technical Reports Server (NTRS)

    Van Dalsem, W. R.; Steger, J. L.

    1983-01-01

    A new, fast, direct-inverse, finite-difference boundary-layer code has been developed and coupled with a full-potential transonic airfoil analysis code via new inviscid-viscous interaction algorithms. The resulting code has been used to calculate transonic separated flows. The results are in good agreement with Navier-Stokes calculations and experimental data. Solutions are obtained in considerably less computer time than Navier-Stokes solutions of equal resolution. Because efficient inviscid and viscous algorithms are used, it is expected this code will also compare favorably with other codes of its type as they become available.

  19. A conservative finite difference algorithm for the unsteady transonic potential equation in generalized coordinates

    NASA Technical Reports Server (NTRS)

    Bridgeman, J. O.; Steger, J. L.; Caradonna, F. X.

    1982-01-01

    An implicit, approximate-factorization, finite-difference algorithm has been developed for the computation of unsteady, inviscid transonic flows in two and three dimensions. The computer program solves the full-potential equation in generalized coordinates in conservation-law form in order to properly capture shock-wave position and speed. A body-fitted coordinate system is employed for the simple and accurate treatment of boundary conditions on the body surface. The time-accurate algorithm is modified to a conventional ADI relaxation scheme for steady-state computations. Results from two- and three-dimensional steady and two-dimensional unsteady calculations are compared with existing methods.

  20. Gender differences in memory processing of female facial attractiveness: evidence from event-related potentials.

    PubMed

    Zhang, Yan; Wei, Bin; Zhao, Peiqiong; Zheng, Minxiao; Zhang, Lili

    2016-06-01

    High rates of agreement in the judgment of facial attractiveness suggest universal principles of beauty. This study investigated gender differences in recognition memory processing of female facial attractiveness. Thirty-four Chinese heterosexual participants (17 females, 17 males) aged 18-24 years (mean age 21.63 ± 1.51 years) participated in the experiment which used event-related potentials (ERPs) based on a study-test paradigm. The behavioral data results showed that both men and women had significantly higher accuracy rates for attractive faces than for unattractive faces, but men reacted faster to unattractive faces. Gender differences on ERPs showed that attractive faces elicited larger early components such as P1, N170, and P2 in men than in women. The results indicated that the effects of recognition bias during memory processing modulated by female facial attractiveness are greater for men than women. Behavioral and ERP evidences indicate that men and women differ in their attentional adhesion to attractive female faces; different mating-related motives may guide the selective processing of attractive men and women. These findings establish a contribution of gender differences on female facial attractiveness during memory processing from an evolutionary perspective. PMID:26928269

  1. [Comparison of steady-state visually evoked potential evoked by different monochromatic light].

    PubMed

    Wu, Zhenghua; Yao, Dezhong

    2008-10-01

    The cone cell on the retina of human is the sensor of vision under illumination; it can be classified into three types: red cone cell, green cone cell, and blue cone cell. There is different property of absorbing light for each type of cone cell. In this work, a 10 Hz pulse was used to drive red, green and blue light emitting diodes respectively, and the different monochromatic light with the same luminance was obtained. The eyes of ten subjects were stimulated by different monochromatic light independently; an EGI system with 128 channels was used to record the steady-state visually evoked potential (SSVEP). After applying the fast fourier transform (FFT) to the SSVEP data, we found that the distribution of the neural network in the initial vision cortex activated by the output of the different-typed cone cell remained mainly identical, but there was some difference in intensity between the three types of network: the activity by blue light is the strongest one, that by red light is in the middle, and that by green light is the weakest one. PMID:19024438

  2. Many QTLs with minor additive effects are associated with a large difference in growth between two selection lines in chickens.

    PubMed

    Jacobsson, Lina; Park, Hee-Bok; Wahlberg, Per; Fredriksson, Robert; Perez-Enciso, Miguel; Siegel, Paul B; Andersson, Leif

    2005-10-01

    Two growth-selected lines in chickens have been developed from a single founder population by divergent selection for body weight at 56 days of age. After more than 40 generations of selection they show a nine-fold difference in body weight at selection age and large differences in growth rate, appetite, fat deposition and metabolic characteristics. We have generated a large intercross between these lines comprising more than 800 F2 birds. QTL mapping revealed 13 loci affecting growth. The most striking observation was that the allele in the high weight line in all cases was associated with enhanced growth, but each locus explained only a small proportion of the phenotypic variance using a standard QTL model (1.3-3.1%). This result is in sharp contrast to our previous study where we reported that the two-fold difference in adult body size between the red junglefowl and White Leghorn domestic chickens is explained by a small number of QTLs with large additive effects. Furthermore, no QTLs for anorexia or antibody response were detected despite large differences for these traits between the founder lines. The result is an excellent example where a large phenotypic difference between populations occurs in the apparent absence of any single locus with large phenotypic effects. The study underscores the need for powerful experimental designs in genetic studies of multifactorial traits. No QTL at all would have reached genome-wide significance using a less powerful design (e.g. approx. 200 F2 individuals) regardless of the nine-fold phenotypic difference between the founder lines for the selected trait. PMID:16356285

  3. Oxidative potential of secondary organic aerosols produced from photooxidation of different hydrocarbons using outdoor chamber under ambient sunlight

    NASA Astrophysics Data System (ADS)

    Jiang, Huanhuan; Jang, Myoseon; Sabo-Attwood, Tara; Robinson, Sarah E.

    2016-04-01

    The oxidative potential of various secondary organic aerosols (SOA) was measured using dithiothreitol (DTT) assay to understand how organic aerosols react with cellular materials. SOA was produced via the photooxidation of four different hydrocarbons (toluene, 1,3,5-trimethylbenzene, isoprene and α-pinene) in the presence of NOx using a large outdoor photochemical smog chamber. The DTT consumption rate was normalized by the aerosol mass, which is expressed as DTTmass. Toluene SOA and isoprene SOA yielded higher DTTmass than 1,3,5-trimethylbenzene SOA or α-pinene SOA. In order to discover the correlation between the molecular structure and oxidative potential, the DTT responses of selected model compounds were also measured. Among them, conjugated aldehydes, quinones, and H2O2 showed considerable DTT response. To investigate the correlation between DTT response and cell responses in vitro, the expression of biological markers, i.e. IL-6, IL-8, and HMOX-1 were studied using small airway epithelial cells. Higher cellular expression of IL-8 was observed with toluene SOA exposure compared to 1,3,5-trimethylbenzene SOA exposure, which aligned with the results from DTT assay. Our study also suggests that within the urban atmosphere, the contribution of toluene SOA and isoprene SOA to the oxidative potential of ambient SOA will be more significant than that of α-pinene SOA.

  4. P300 EVENT RELATED POTENTIAL IN NORMAL HEALTHY CONTROLS OF DIFFERENT AGE GROUPS

    PubMed Central

    Shukla, R.; Trivedi, J.K.; Singh, R.; Singh, Y.; Chakravorty, P.

    2000-01-01

    P300 event related potential was recorded in 115 healthy controls with a mean age of35.9±14.81 years and a male : female ratio of 72 : 43. There was significant difference in the P300 latency in < 40 years as compared to ≥ 40 years group (p< 0.001). There was no significant difference between males and females. There was a strong positive correlation between age and P300 latency (p< 0.001). The regression equation for P300 latency was Y=287.9+1.492x with an SEE of 20.2 (where Y is the P300 latency in ms, x is the age in years, SEE is the standard error of estimate). There was a negative correlation between age and P300 amplitude which was significant in ≥ 40 years age group while in > 40 years age group it was not significant. PMID:21407977

  5. Direction-dependent spectral sensitivity and interaural spectral difference in a dolphin: evoked potential study.

    PubMed

    Supin AYa; Popov, V V

    1993-06-01

    Sensitivity and interaural intensity difference (IID) dependence on sound frequency and direction was measured in an Amazon river dolphin Inia geoffrensis by recording the auditory nerve evoked response from the body surface. The maximal sensitivity in the horizontal plane was found when the sound direction was 5 degrees to 10 degrees ipsilateral to the recorded ear; the direction dependence of sensitivity was more pronounced at higher frequencies than at lower ones. The IID reached its peak at small azimuthal angles (7.5 degrees to 15 degrees) and higher sound frequencies (100 kHz), or at large azimuthal angles (30 degrees to 45 degrees) and lower sound frequencies (20 to 30 kHz). Each sound direction featured its specific pattern of spectral sensitivity and of interaural spectral difference. The interaural spectral difference fluctuated within a range of more than 20 dB depending on sound direction. The data indicate that interaural intensity as well as spectral difference may be cues for binaural localization of sound direction by dolphins. PMID:8326074

  6. Apollo 14 regolith breccias - Different glass populations and their potential for charting space time variations

    NASA Technical Reports Server (NTRS)

    Delano, John W.

    1988-01-01

    Apollo 14 regolith breccias (14313, 14307, 14301, 14049, 14047) have been found to have different populations of nonagglutinitic, mare-derived glasses. These variations appear to not only reflect different source regoliths but also different closure ages for these breccias. Based upon these different glass populations, 14301 is inferred to have a closure age sometime during the epoch of mare volcanism. All of the other four breccias were formed after the termination of mare volcanism with a possible age sequence from old to young of the following: 14307, 14313, 14049, 14047. Due to the relative simplicity of acquiring high-quality chemical data on large numbers of glasses by electron microprobe, mare glass populations allow: (1) classification of regolith breccias with respect to provenance and (2) estimation of their relative and absolute closure ages. The determination of (Ar-40)-(Ar-39) ages on individual glass spherules within breccias using the laser probe should in the future prove to be a promising extension of the present study.

  7. Theory of Cooper-pair mass spectroscopy by the current-induced contact-potential difference

    SciTech Connect

    Mishonov, T.M. )

    1994-08-01

    The creation of contactless Cooper-pair mass spectroscopy based on the Bernoulli-Venturi effect in thin superconducting films is suggested. The preparation of layered metal-insulator-superconductor-type heterostructures and standard electronics are necessary for the realization of the method. Two electrodes are patterned from the metallic layer: a circle and concentric-ring electrode. The currents in the superconducting film are induced by a drive coil concentric to the electrodes. The Bernoulli potential of the charged Cooper-pair superfluid creates a measurable electric polarization of gate electrodes of this plane-capacitor device. The current-induced contact-potential difference is limited by the Ginzburg-Landau potential [minus][ital a][sub GL]([ital T])= 1/2[h bar][ital e][sup *][ital H][sub [ital c]2]([ital T])/[ital m][sup *][ital c]=[h bar][sup 2]/2[ital m][sup *][xi][sup 2]([ital T]). The additional charge of the polarized circular electrode has the same sign as the free charge carriers of the superconductor.

  8. Estimating Sugarcane Yield Potential Using an In-Season Determination of Normalized Difference Vegetative Index

    PubMed Central

    Lofton, Josh; Tubana, Brenda S.; Kanke, Yumiko; Teboh, Jasper; Viator, Howard; Dalen, Marilyn

    2012-01-01

    Estimating crop yield using remote sensing techniques has proven to be successful. However, sugarcane possesses unique characteristics; such as, a multi-year cropping cycle and plant height-limiting for midseason fertilizer application timing. Our study objective was to determine if sugarcane yield potential could be estimated using an in-season estimation of normalized difference vegetative index (NDVI). Sensor readings were taken using the GreenSeeker® handheld sensor from 2008 to 2011 in St. Gabriel and Jeanerette, LA, USA. In-season estimates of yield (INSEY) values were calculated by dividing NDVI by thermal variables. Optimum timing for estimating sugarcane yield was between 601–750 GDD. In-season estimated yield values improved the yield potential (YP) model compared to using NDVI. Generally, INSEY value showed a positive exponential relationship with yield (r2 values 0.48 and 0.42 for cane tonnage and sugar yield, respectively). When models were separated based on canopy structure there was an increase the strength of the relationship for the erectophile varieties (r2 0.53 and 0.47 for cane tonnage and sugar yield, respectively); however, the model for planophile varieties weakened slightly. Results of this study indicate using an INSEY value for predicting sugarcane yield shows potential of being a valuable management tool for sugarcane producers in Louisiana. PMID:22969359

  9. Investigation of potential waste material insulating properties at different temperature for thermal storage application

    NASA Astrophysics Data System (ADS)

    Ali, T. Z. S.; Rosli, A. B.; Gan, L. M.; Billy, A. S.; Farid, Z.

    2013-12-01

    Thermal energy storage system (TES) is developed to extend the operation of power generation. TES system is a key component in a solar energy power generation plant, but the main issue in designing the TES system is its thermal capacity of storage materials, e.g. insulator. This study is focusing on the potential waste material acts as an insulator for thermal energy storage applications. As the insulator is used to absorb heat, it is needed to find suitable material for energy conversion and at the same time reduce the waste generation. Thus, a small-scale experimental testing of natural cooling process of an insulated tank within a confined room is conducted. The experiment is repeated by changing the insulator from the potential waste material and also by changing the heat transfer fluid (HTF). The analysis presented the relationship between heat loss and the reserved period by the insulator. The results show the percentage of period of the insulated tank withstands compared to tank insulated by foam, e.g. newspaper reserved the period of 84.6% as much as foam insulated tank to withstand the heat transfer of cooking oil to the surrounding. The paper finally justifies the most potential waste material as an insulator for different temperature range of heat transfer fluid.

  10. Gender Differences in Achievement in a Large, Nationally Representative Sample of Children and Adolescents

    ERIC Educational Resources Information Center

    Scheiber, Caroline; Reynolds, Matthew R.; Hajovsky, Daniel B.; Kaufman, Alan S.

    2015-01-01

    The purpose of this study was to investigate developmental gender differences in academic achievement areas, with the primary focus on writing, using the child and adolescent portion (ages 6-21 years) of the "Kaufman Test of Educational Achievement-Second Edition, Brief Form," norming sample (N = 1,574). Path analytic models with gender,…

  11. Who Gets Market Supplements? Gender Differences within a Large Canadian University

    ERIC Educational Resources Information Center

    Doucet, Christine; Durand, Claire; Smith, Michael

    2008-01-01

    This study examines the gender pay gap among university faculty by analyzing gender differences in one component of faculty members' salaries--"market premiums." The data were collected during the Fall of 2002 using a survey of faculty at a single Canadian research university. Correspondence analysis and logistic regression analysis were performed…

  12. Racial differences in obesity measures and risk of colorectal adenomas in a large screening population.

    PubMed

    Murphy, Caitlin C; Martin, Christopher F; Sandler, Robert S

    2015-01-01

    Obesity is an important risk factor for colorectal neoplasia; however, little research exists on racial differences in obesity measures [body mass index (BMI), waist circumference (WC), and waist-hip-ratio (WHR)] associated with adenoma. We used data from the Diet and Health Studies, Phases III-V to examine differences in the contribution of obesity measures to adenoma risk by race. The sample consisted of 2184 patients (1806 white, 378 African American) undergoing outpatient colonoscopy for average risk screening. Covariates included demographics, health history, and validated measures of diet and physical activity. Among whites, BMI [overweight: odds ratio (OR) = 1.31, 95% confidence interval (CI), 1.00-1.71; obese: OR = 1.89, 95% CI, 1.41-2.56), WC (OR = 1.47, 95% CI, 1.09-1.99), and WHR (OR = 1.60, 95% CI, 1.24-2.06) were associated with adenomas. BMI was not associated with adenomas in African Americans. Although the CIs were wide, the point estimates for WHR (OR = 1.07, 95% CI, 0.51-2.22) and WC (OR = 1.04, 95% CI, 0.56-1.92) were slightly elevated above the null. BMI was associated with adenomas only among whites, whereas WHR and WC appeared to be important risk factors among both races. Racial differences in adenoma risk may be due to differences in body shape and weight and/or fat distribution. PMID:25425186

  13. Differences in phosphorylation of the two large subunits of brine shrimp Na,K-ATPase.

    PubMed

    Churchill, L

    1984-09-01

    Analysis of purified Na,K-ATPase from brine shrimp nauplii revealed two molecular forms of the alpha subunit separable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis [G.L. Peterson, R.D. Ewing, S.R. Hootman, and F.P. Conte (1978) J. Biol. Chem. 253:4762]. The molecular form with lower mobility is designated alpha 1 and the one with higher mobility, alpha 2, in a neutral or alkaline gel system. Differences in Na+-dependent, K+-sensitive phosphorylation of these two molecular forms have been investigated by directly measuring the radioactivity present in each phosphoprotein after separation of the two forms by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the presence of Na+,Mg2+, and ATP, when the ATP concentration is above 1 microM, both alpha subunits are phosphorylated, although the phosphoprotein content of alpha 1 is considerably greater than that of alpha 2. Below 1 microM ATP, the phosphoprotein content of alpha 2 is even further reduced. These striking differences in phosphorylation at low ATP concentrations are not due to a greater instability of the alpha 2 phosphoprotein during the long electrophoresis times or during fixation, staining, and destaining. The proportion of total phosphoprotein content in alpha 2, as well as the relationship between phosphoprotein content and ATP concentration, is unchanged when the radioactive analysis is performed on frozen gels that have been electrophoresed for shorter times, even though the actual amount of phosphorylation is 15 times greater than with fixed gels. Since the concentration of alpha 1 and alpha 2 vary during development [G.L. Peterson, L. Churchill, J.A. Fisher, and L.E. Hokin (1982) J. Exp. Zool. 221:295], the differences in phosphorylation may be relevant to differences in Na,K-ATPase activity during different development stages. PMID:6094698

  14. The role of the transbranchial potential difference in hyperosmotic regulation of the shore crab Carcinus maenas

    NASA Astrophysics Data System (ADS)

    Winkler, Andreas

    1986-03-01

    When isolated gills of the shore crab Carcinus maenas were bathed and perfused with identical solutions on both sides (50 % sea water), a spontaneous transepithelial potential difference (PD) of some millivolts (hemolymph side negative) was established. This PD is of active nature and requires the metabolism of the living cell, since it uses its own sources of energy in addition to organic nutrients offered in the flow of artificial hemolymph. Addition of sodium cyanide and dinitrophenole to bathing and perfusion medium resulted in reversible breakdown of PDs in a concentration-dependent mode. In posterior gills of C. maenas, the potential differences were more negative compared to data measured in anterior gills of the same individuals. These results are correlated with higher specific activities of Na-K-ATPase in posterior gills. Experiments with triamterene indicate that sodium uptake in C. maenas is sensitive to this diuretic drug, when applied on the apical side of the epithelial cell. The results obtained show that active uptake of sodium from medium to blood across the gills is performed by a complex mechanism including participation of several basal and apical transport steps.

  15. Large systematic trend difference between national and regional homogenized datasets and global collections

    NASA Astrophysics Data System (ADS)

    Venema, Victor

    2016-04-01

    The global land temperature trend may be biased due to remaining inhomogeneities. Well-homogenized national datasets on average clearly show more warming than global collections when averaged over the region of common coverage. For this study we have collected a dataset with more than 40 national and regional average monthly temperature series (called "national" from now on). National datasets can be better homogenized than global ones. More data is available at national weather services to serve as a reference in the detection and correction of breaks. More stations and knowledge of the local climatology can help in selecting better references that are expected to have the same climate signal. More metadata is available nationally on network-wide breaks and to determine the right date of the statistically detected breaks. Furthermore, better homogenization methods are available for regional networks. Here we compare these national datasets to the global collections BEST, CRUCY, CRUTEM4, GHCNv3 and GISS. For all datasets the country average series have been computed. A subset of 10 well-homogenized national datasets shows a clearly stronger temperature trend, which is several tenths of a degree Celsius per century larger and mostly statistically significant. These differences are seen for the entire period between 1800 and now. The differences are smallest for CRUTEM4 and CRUCY, which include homogenized data from many of our national datasets. The differences are largest for BEST and GISS. GHCN represents a middle case. We are working on better understanding these differences by comparing all datasets, which range from raw data to data homogenized by various methods and which use a range of different methods to compute the national average. We look for relationships between the methods used for homogenization and averaging and the trend differences. In an accompanying poster, we i) review the literature on trend uncertainties due to remaining inhomogeneities, ii

  16. Genetic differences in hepatic lipid peroxidation potential and iron levels in mice.

    PubMed

    Gerhard, Glenn S; Kaufmann, Elizabeth J; Wang, Xujun; Erikson, Keith M; Abraham, Joseph; Grundy, Martin; Beard, John L; Chorney, Michael J

    2002-01-01

    Oxidative damage to macromolecules, including lipids, has been hypothesized as a mechanism of aging. One end product of lipid peroxidation, malondialdehyde (MDA), is often quantified as a measure of oxidative damage to lipids. We used a commercial colorimetric assay for MDA (Bioxytech LPO-586, Oxis International, Portland, OR) to measure lipid peroxidation potential in liver tissue from young (2 month) male mice from recombinant inbred (RI) mouse strains from the C57BL/6J (B6)xDBA/2J (D2) series (BXD). The LPO-586 assay (LPO) reliably detected significant differences (P<0.0001) in lipid peroxidation potential between the B6 and D2 parental strains, and yielded a more than two-fold variation across the BXD RI strains. In both B6 and D2 mice, LPO results were greater in old (23 month) mice, with a larger age-related increase in the D2 strain. As the level of iron can influence lipid peroxidation, we also measured hepatic non-heme iron levels in the same strains. Although iron level exhibited a slightly negative overall correlation (r(2)=0.119) with LPO results among the entire group of BXD RI strains, a sub-group with lower LPO values were highly correlated (r(2)=0.704). LPO results were also positively correlated with iron levels from a group of 8 other inbred mouse strains (r(2)=0.563). The BXD RI LPO data were statistically analyzed to nominate quantitaive trait loci (QTL). A single marker, Zfp4, which maps to 55.2 cM on chromosome 8, achieved a significance level of P<0.0006. At least two potentially relevant candidate genes reside close to this chromosomal position. Hepatic lipid peroxidation potential appears to be a strain related trait in mice that is amenable to QTL analysis. PMID:11718810

  17. Symbiotic potential and survival of native rhizobia kept on different carriers

    PubMed Central

    Ruíz-Valdiviezo, Víctor Manuel; Canseco, Lucía María Cristina Ventura; Suárez, Luis Antonio Castillo; Gutiérrez-Miceli, Federico Antonio; Dendooven, Luc; Rincón-Rosales, Reiner

    2015-01-01

    Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N2 fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7T and Rhizobium calliandrae LBP2-1T and of the reference strain Rhizobium etli CFN42T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1T, 167% for strain CFN42T and 219% for strain ITTG R7T) than for the other carriers after 240 days, except for CFN42T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7T was kept on PSB. The nitrogenase activity was the highest for ITTG R7T kept on PEAT (4911 μmol C2H4 per fresh weight nodule h−1); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them. PMID:26413054

  18. Symbiotic potential and survival of native rhizobia kept on different carriers.

    PubMed

    Ruíz-Valdiviezo, Víctor Manuel; Canseco, Lucía María Cristina Ventura; Suárez, Luis Antonio Castillo; Gutiérrez-Miceli, Federico Antonio; Dendooven, Luc; Rincón-Rosales, Reiner

    2015-01-01

    Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N2 fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7(T) and Rhizobium calliandrae LBP2-1(T) and of the reference strain Rhizobium etli CFN42(T). A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1(T), 167% for strain CFN42(T) and 219% for strain ITTG R7(T)) than for the other carriers after 240 days, except for CFN42(T) kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42(T) was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7(T) was kept on PSB. The nitrogenase activity was the highest for ITTG R7(T) kept on PEAT (4911 μmol C2H4 per fresh weight nodule h(-1)); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them. PMID:26413054

  19. Large Thermal Conductivity Differences between the Crystalline and Vitrified States of DMSO with Applications to Cryopreservation

    PubMed Central

    Ehrlich, Lili E.; Feig, Justin S. G.; Schiffres, Scott N.; Malen, Jonathan A.; Rabin, Yoed

    2015-01-01

    Thermal conductivity of dimethyl-sulfoxide (DMSO) solution is measured in this study using a transient hot wire technique, where DMSO is a key ingredient in many cryoprotective agent (CPA) cocktails. Characterization of thermal properties of cryoprotective agents is essential to the analysis of cryopreservation processes, either when evaluating experimental data or for the design of new protocols. Also presented are reference measurements of thermal conductivity for pure water ice and glycerol. The thermal conductivity measurement setup is integrated into the experimentation stage of a scanning cryomacroscope apparatus, which facilitates the correlation of measured data with visualization of physical events. Thermal conductivity measurements were conducted for a DMSO concentration range of 2M and 10M, in a temperature range of -180°C and 25°C. Vitrified samples showed decreased thermal conductivity with decreasing temperature, while crystalline samples showed increased thermal conductivity with decreasing temperature. These different behaviors result in up to a tenfold difference in thermal conductivity at -180°C. Such dramatic differences can drastically impact heat transfer during cryopreservation and their quantification is therefore critical to cryobiology. PMID:25985058

  20. Intraurban Differences in the Use of Ambulatory Health Services in a Large Brazilian City

    PubMed Central

    Lima-Costa, Maria Fernanda; Proietti, Fernando Augusto; Cesar, Cibele C.; Macinko, James

    2010-01-01

    A major goal of health systems is to reduce inequities in access to services, that is, to ensure that health care is provided based on health needs rather than social or economic factors. This study aims to identify the determinants of health services utilization among adults in a large Brazilian city and intraurban disparities in health care use. We combine household survey data with census-derived classification of social vulnerability of each household’s census tract. The dependent variable was utilization of physician services in the prior 12 months, and the independent variables included predisposing factors, health needs, enabling factors, and context. Prevalence ratios and 95% confidence intervals were estimated by the Hurdle regression model, which combined Poisson regression analysis of factors associated with any doctor visits (dichotomous variable) and zero-truncated negative binomial regression for the analysis of factors associated with the number of visits among those who had at least one. Results indicate that the use of health services was greater among women and increased with age, and was determined primarily by health needs and whether the individual had a regular doctor, even among those living in areas of the city with the worst socio-environmental indicators. The experience of Belo Horizonte may have implications for other world cities, particularly in the development and use of a comprehensive index to identify populations at risk and in order to guide expansion of primary health care services as a means of enhancing equity in health. PMID:21104332

  1. Different effects of laser contrast on proton emission from normal large foils and transverse-size-reduced targets

    NASA Astrophysics Data System (ADS)

    Fang, Yuan; Ge, Xulei; Yang, Su; Wei, Wenqing; Yu, Tongpu; Liu, Feng; Chen, Min; Liu, Jingquan; Yuan, Xiaohui; Sheng, Zhengming; Zhang, Jie

    2016-07-01

    We report experimental results on the effects of laser contrast on beam divergence and energy spectrum of protons emitted from ultrashort intense laser interactions with normal large foils and transverse-size-reduced targets. Correlations between beam divergence and spectral shape are found. Large divergence and near-plateau shape energy spectrum are observed for both types of targets when the laser pulse contrast is low. With high contrast laser irradiation, proton beam divergence is remarkably reduced and the energy spectral shape is changed to exponential for large foil targets. In comparison, a similar large divergence and the near-plateau spectral shape remain for transverse-size-reduced targets. The results could be explained by the preplasma formation and target deformation at different laser contrasts and modified accelerating sheath field evolution in transverse-size-reduced target, which were supported by the 2D hydrodynamic and PIC simulations.

  2. Potential of infrared spectroscopy in combination with extended canonical variate analysis for identifying different paper types

    NASA Astrophysics Data System (ADS)

    Riba, Jordi-Roger; Canals, Trini; Cantero, Rosa; Iturriaga, Hortensia

    2011-02-01

    The increasing use of secondary fiber in papermaking has led to the production of paper containing a wide range of contaminants. Wastepaper mills need to develop quality control methods for evaluating the incoming wastepaper stock as well as testing the specifications of the final product. The goal of this work is to present a fast and successful methodology for identifying different paper types. In this way, undesirable paper types can be refused, thus improving the runnability of the paper machine and the quality of the paper manufactured. In this work we examine various types of paper using information obtained by an appropriate chemometric treatment of infrared spectral data. For this purpose, we studied a large number of paper sheets of three different types (namely coated, offset and cast-coated) supplied by several paper manufacturers. We recorded Fourier transform infrared (FTIR) spectra with the aid of an attenuated total reflectance (ATR) module and near-infrared (NIR) reflectance spectra by means of fiber optics. Both techniques proved expeditious and required no sample pretreatment. The primary objective of this work was to develop a methodology for the accurate identification of samples of different paper types. For this purpose, we used the chemometric discrimination technique extended canonical variate analysis (ECVA) in combination with the k nearest neighbor (kNN) method to classify samples in the prediction set. Use of the NIR and FTIR techniques under these conditions allowed paper types to be identified with 100% success in prediction samples.

  3. Potential of GPS Common Clock Single-differences for Deformation Monitoring

    NASA Astrophysics Data System (ADS)

    Schön, Steffen; Pham, Hue Kiem; Kersten, Tobias; Leute, Julia; Bauch, Andreas

    2016-03-01

    Global satellite navigation systems (GNSS) are a standard measurement device for deformation monitoring. In many applications, double-differences are used to reduce distance dependent systematic effects, as well as to eliminate the receiver and satellites clock errors. However, due to the navigation principle of one way ranging used in GPS, the geometry of the subsequent adjustment is weakened. As a result, the height component is generally determined three times less precisely than the horizontal coordinates. In addition, large correlations between the height and elevation dependent effects exist such as tropospheric refraction, mismodelled phase center variations, or multipath which restricts the attainable accuracy. However, for a kinematic analysis, i. e. for estimating high rate coordinate time series, the situation can be significantly improved if a common clock is connected to different GNSS receivers in a network or on a baseline. Consequently, between-station single-differences are sufficient to solve for the baseline coordinates. The positioning geometry is significantly improved which is reflected by a reduction of the standard deviation of kinematic heights by about a factor 3 underlining the benefits of this new approach. Real data from baselines at the Physikalisch-Technische Bundesanstalt campus at Braunschweig where receivers are connected over 290 m via an optical fiber link to a common clock was analysed.

  4. Addressing impacts of different statistical downscaling methods on large scale hydrologic simulations

    NASA Astrophysics Data System (ADS)

    Mizukami, N.; Clark, M. P.; Gutmann, E. D.; Mendoza, P. A.; Brekke, L. D.; Arnold, J.; Raff, D. A.

    2013-12-01

    Many hydrologic assessments, such as evaluations of climate change impacts on water resources, require downscaled climate model outputs to force hydrologic simulations at a spatial resolution finer than the climate models' native scale. Statistical downscaling is an attractive alternative to dynamical downscaling methods for continental scale hydrologic applications because of its lower computational cost. The goal of this study is to illustrate and compare how the errors in precipitation and temperature produced by different statistical downscaling methods propagate into hydrologic simulations. Multi-decadal hydrologic simulations were performed with three process-based hydrologic models (CLM, VIC, and PRMS) forced by multiple climate datasets over the contiguous United States. The forcing datasets include climate data derived from gauge observations (M02) as well as climate data downscaled from the NCEP-NCAR reanalysis using 4 statistical downscaling methods for a domain with 12-km grid spacing: two forms of Bias Corrected Spatially Disaggregated methods (BCSD-monthly and BCSD-daily), Bias Corrected Constructed Analogue (BCCA), and Asynchronous Regression (AR). Our results show that both BCCA and BCSD-daily underestimate extreme precipitation events while AR produces these correctly at the scale at which the simulations were run but does not scale them up appropriately to larger basin scales like HUC-4 and HUC-2. These artifacts lead to a poor representation of flooding events when hydrologic models are forced by these methods over a range of spatial scales. We also illustrate that errors in precipitation depths dominate impacts on runoff depth estimations, and that errors in wet day frequency have a larger effect on shortwave radiation estimations than do the errors in temperatures; this error subsequently affects the partitioning of precipitation into evaporation and runoff as we show over mountainous areas of the upper Colorado River. Finally we show the inter

  5. Nonsurgical management of large periapical lesion in mature and immature teeth using different calcium hydroxide formulations: case series.

    PubMed

    Kumar, G Vinay; Hegde, Reshma S; Moogi, Prashant P; Prashant, B R; Patil, Basanagouda

    2013-01-01

    This case series evaluates the effectiveness of different calcium hydroxide formulations with various vehicles in management of large periapical lesion in mature and immature teeth. This will help clinicians to make informed judgments about which formulations of calcium hydroxide should be used for specific endodontic procedures. PMID:24858773

  6. Flat tree-level inflationary potentials in the light of cosmic microwave background and large scale structure data

    NASA Astrophysics Data System (ADS)

    Ballesteros, G.; Casas, J. A.; Espinosa, J. R.; Ruiz de Austri, R.; Trotta, R.

    2008-03-01

    We use cosmic microwave background (CMB) and large scale structure (LSS) data to test a broad and physically well-motivated class of inflationary models: those with flat tree-level potentials (typical in supersymmetry). The non-trivial features of the potential arise from radiative corrections which give a simple logarithmic dependence on the inflaton field, making the models very predictive. We also consider a modified scenario with new physics beyond a certain high energy cut-off showing up as non-renormalizable operators (NRO) in the inflaton field. We find that both kinds of models fit CMB and LSS data remarkably well, with very few free parameters. Besides, many of these models naturally predict a reasonable number of e-folds. A robust feature of these scenarios is the smallness of tensor perturbations (r \\lesssim 10^{-3} ). The NRO case can give a sizable running of the spectral index while achieving a sufficient number of e-folds. We use Bayesian model comparison tools to assess the relative performance of the models. We believe that these scenarios can be considered as a standard physical class of inflationary models, on a similar footing to monomial potentials.

  7. Motor unit potential morphology differences in individuals with non-specific arm pain and lateral epicondylitis

    PubMed Central

    Calder, Kristina M; Stashuk, Daniel W; McLean, Linda

    2008-01-01

    Background The pathophysiology of non-specific arm pain (NSAP) is unclear and the diagnosis is made by excluding other specific upper limb pathologies, such as lateral epicondylitis or cervical radiculopathy. The purpose of this study was to determine: (i) if the quantitative parameters related to motor unit potential morphology and/or motor unit firing patterns derived from electromyographic (EMG) signals detected from an affected muscle of patients with NSAP are different from those detected in the same muscle of individuals with lateral epicondylitis (LE) and/or control subjects and (ii) if the quantitative EMG parameters suggest that the underlying pathophysiology in NSAP is either myopathic or neuropathic in nature. Methods Sixteen subjects with NSAP, 11 subjects with LE, eight subjects deemed to be at-risk for developing a repetitive strain injury, and 37 control subjects participated. A quantitative electromyography evaluation was completed using decomposition-based quantitative electromyography (DQEMG). Needle- and surface-detected EMG signals were collected during low-level isometric contractions of the extensor carpi radialis brevis (ECRB) muscle. DQEMG was used to extract needle-detected motor unit potential trains (MUPTs), and needle-detected motor unit potential (MUP) and surface detected motor unit potential (SMUP) morphology and motor unit (MU) firing rates were compared among the four groups using one-way analysis of variance (ANOVA). Post hoc analyses were performed using Tukey's pairwise comparisons. Results Significant group differences were found for all MUP variables and for MU firing rate (p < 0.006). The post-hoc analyses revealed that patients with NSAP had smaller MUP amplitude and SMUP amplitude and area compared to the control and LE groups (p < 0.006). MUP duration and AAR values were significantly larger in the NSAP, LE and at-risk groups compared to the control group (p < 0.006); while MUP amplitude, duration and AAR values were

  8. Isotopic Differences between Forage Consumed by a Large Herbivore in Open, Closed, and Coastal Habitats: New Evidence from a Boreal Study System

    PubMed Central

    Giroux, Marie-Andrée; Valiquette, Éliane; Tremblay, Jean-Pierre; Côté, Steeve D.

    2015-01-01

    Documenting habitat-related patterns in foraging behaviour at the individual level and over large temporal scales remains challenging for large herbivores. Stable isotope analysis could represent a valuable tool to quantify habitat-related foraging behaviour at the scale of individuals and over large temporal scales in forest dwelling large herbivores living in coastal environments, because the carbon (δ13C) or nitrogen (δ15N) isotopic signatures of forage can differ between open and closed habitats or between terrestrial and littoral forage, respectively. Here, we examined if we could detect isotopic differences between the different assemblages of forage taxa consumed by white-tailed deer that can be found in open, closed, supralittoral, and littoral habitats. We showed that δ13C of assemblages of forage taxa were 3.0‰ lower in closed than in open habitats, while δ15N were 2.0‰ and 7.4‰ higher in supralittoral and littoral habitats, respectively, than in terrestrial habitats. Stable isotope analysis may represent an additional technique for ecologists interested in quantifiying the consumption of terrestrial vs. marine autotrophs. Yet, given the relative isotopic proximity and the overlap between forage from open, closed, and supralittoral habitats, the next step would be to determine the potential to estimate their contribution to herbivore diet. PMID:26559186

  9. Isotopic Differences between Forage Consumed by a Large Herbivore in Open, Closed, and Coastal Habitats: New Evidence from a Boreal Study System.

    PubMed

    Giroux, Marie-Andrée; Valiquette, Éliane; Tremblay, Jean-Pierre; Côté, Steeve D

    2015-01-01

    Documenting habitat-related patterns in foraging behaviour at the individual level and over large temporal scales remains challenging for large herbivores. Stable isotope analysis could represent a valuable tool to quantify habitat-related foraging behaviour at the scale of individuals and over large temporal scales in forest dwelling large herbivores living in coastal environments, because the carbon (δ13C) or nitrogen (δ15N) isotopic signatures of forage can differ between open and closed habitats or between terrestrial and littoral forage, respectively. Here, we examined if we could detect isotopic differences between the different assemblages of forage taxa consumed by white-tailed deer that can be found in open, closed, supralittoral, and littoral habitats. We showed that δ13C of assemblages of forage taxa were 3.0 ‰ lower in closed than in open habitats, while δ15N were 2.0 ‰ and 7.4 ‰ higher in supralittoral and littoral habitats, respectively, than in terrestrial habitats. Stable isotope analysis may represent an additional technique for ecologists interested in quantifiying the consumption of terrestrial vs. marine autotrophs. Yet, given the relative isotopic proximity and the overlap between forage from open, closed, and supralittoral habitats, the next step would be to determine the potential to estimate their contribution to herbivore diet. PMID:26559186

  10. Large difference in carbon emission - burial balances between boreal and arctic lakes

    NASA Astrophysics Data System (ADS)

    Lundin, E. J.; Klaminder, J.; Bastviken, D.; Olid, C.; Hansson, S. V.; Karlsson, J.

    2015-09-01

    Lakes play an important role in the global carbon (C) cycle by burying C in sediments and emitting CO2 and CH4 to the atmosphere. The strengths and control of these fundamentally different pathways are therefore of interest when assessing the continental C balance and its response to environmental change. In this study, based on new high-resolution estimates in combination with literature data, we show that annual emission:burial ratios are generally ten times higher in boreal compared to subarctic - arctic lakes. These results suggest major differences in lake C cycling between biomes, as lakes in warmer boreal regions emit more and store relatively less C than lakes in colder arctic regions. Such effects are of major importance for understanding climatic feedbacks on the continental C sink - source function at high latitudes. If predictions of global warming and northward expansion of the boreal biome are correct, it is likely that increasing C emissions from high latitude lakes will partly counteract the presumed increasing terrestrial C sink capacity at high latitudes.

  11. Different Binding Modes of Small and Large Binders of GAT1.

    PubMed

    Wein, Thomas; Petrera, Marilena; Allmendinger, Lars; Höfner, Georg; Pabel, Jörg; Wanner, Klaus T

    2016-03-01

    Well-known inhibitors of the γ-aminobutyric acid (GABA) transporter GAT1 share a common scaffold of a small cyclic amino acid linked by an alkyl chain to a moiety with two aromatic rings. Tiagabine, the only FDA-approved GAT1 inhibitor, is a typical example. Some small amino acids such as (R)-nipecotic acid are medium-to-strong binders of GAT1, but similar compounds, such as proline, are very weak binders. When substituted with 4,4-diphenylbut-3-en-1-yl (DPB) or 4,4-bis(3-methylthiophen-2-yl)but-3-en-1-yl (BTB) groups, the resulting compounds have similar pKi and pIC50 values, even though the pure amino acids have very different values. To investigate if small amino acids and their substituted counterparts share a similar binding mode, we synthesized butyl-, DPB-, and BTB-substituted derivatives of small amino acids. Supported by the results of docking studies, we propose different binding modes not only for unsubstituted und substituted, but also for strong- and weak-binding amino acids. These data lead to the conclusion that following a fragment-based approach, not pure but N-butyl-substituted amino acids should be used as starting points, giving a better estimate of the activity when a BTB or DPB substituent is added. PMID:26804464

  12. Large difference in carbon emission – burial balances between boreal and arctic lakes

    PubMed Central

    Lundin, E. J.; Klaminder, J.; Bastviken, D.; Olid, C.; Hansson, S. V.; Karlsson, J.

    2015-01-01

    Lakes play an important role in the global carbon (C) cycle by burying C in sediments and emitting CO2 and CH4 to the atmosphere. The strengths and control of these fundamentally different pathways are therefore of interest when assessing the continental C balance and its response to environmental change. In this study, based on new high-resolution estimates in combination with literature data, we show that annual emission:burial ratios are generally ten times higher in boreal compared to subarctic – arctic lakes. These results suggest major differences in lake C cycling between biomes, as lakes in warmer boreal regions emit more and store relatively less C than lakes in colder arctic regions. Such effects are of major importance for understanding climatic feedbacks on the continental C sink – source function at high latitudes. If predictions of global warming and northward expansion of the boreal biome are correct, it is likely that increasing C emissions from high latitude lakes will partly counteract the presumed increasing terrestrial C sink capacity at high latitudes. PMID:26370519

  13. Large-scale mass spectrometric detection of variant peptides resulting from non-synonymous nucleotide differences

    PubMed Central

    Sheynkman, Gloria M.; Shortreed, Michael R.; Frey, Brian L.; Scalf, Mark; Smith, Lloyd M.

    2013-01-01

    Each individual carries thousands of non-synonymous single nucleotide variants (nsSNVs) in their genome, each corresponding to a single amino acid polymorphism (SAP) in the encoded proteins. It is important to be able to directly detect and quantify these variations at the protein level in order to study post-transcriptional regulation, differential allelic expression, and other important biological processes. However, such variant peptides are not generally detected in standard proteomic analyses, due to their absence from the generic databases that are employed for mass spectrometry searching. Here, we extend previous work that demonstrated the use of customized SAP databases constructed from sample-matched RNA-Seq data. We collected deep coverage RNA-Seq data from the Jurkat cell line, compiled the set of nsSNVs that are expressed, used this information to construct a customized SAP database, and searched it against deep coverage shotgun MS data obtained from the same sample. This approach enabled detection of 421 SAP peptides mapping to 395 nsSNVs. We compared these peptides to peptides identified from a large generic search database containing all known nsSNVs (dbSNP) and found that more than 70% of the SAP peptides from this dbSNP-derived search were not supported by the RNA-Seq data, and thus are likely false positives. Next, we increased the SAP coverage from the RNA-Seq derived database by utilizing multiple protease digestions, thereby increasing variant detection to 695 SAP peptides mapping to 504 nsSNV sites. These detected SAP peptides corresponded to moderate to high abundance transcripts (30+ transcripts per million, TPM). The SAP peptides included 192 allelic pairs; the relative expression levels of the two alleles were evaluated for 51 of those pairs, and found to be comparable in all cases. PMID:24175627

  14. Differences in human cortical gene expression match the temporal properties of large-scale functional networks.

    PubMed

    Cioli, Claudia; Abdi, Hervé; Beaton, Derek; Burnod, Yves; Mesmoudi, Salma

    2014-01-01

    We explore the relationships between the cortex functional organization and genetic expression (as provided by the Allen Human Brain Atlas). Previous work suggests that functional cortical networks (resting state and task based) are organized as two large networks (differentiated by their preferred information processing mode) shaped like two rings. The first ring--Visual-Sensorimotor-Auditory (VSA)--comprises visual, auditory, somatosensory, and motor cortices that process real time world interactions. The second ring--Parieto-Temporo-Frontal (PTF)--comprises parietal, temporal, and frontal regions with networks dedicated to cognitive functions, emotions, biological needs, and internally driven rhythms. We found--with correspondence analysis--that the patterns of expression of the 938 genes most differentially expressed across the cortex organized the cortex into two sets of regions that match the two rings. We confirmed this result using discriminant correspondence analysis by showing that the genetic profiles of cortical regions can reliably predict to what ring these regions belong. We found that several of the proteins--coded by genes that most differentiate the rings--were involved in neuronal information processing such as ionic channels and neurotransmitter release. The systematic study of families of genes revealed specific proteins within families preferentially expressed in each ring. The results showed strong congruence between the preferential expression of subsets of genes, temporal properties of the proteins they code, and the preferred processing modes of the rings. Ionic channels and release-related proteins more expressed in the VSA ring favor temporal precision of fast evoked neural transmission (Sodium channels SCNA1, SCNB1 potassium channel KCNA1, calcium channel CACNA2D2, Synaptotagmin SYT2, Complexin CPLX1, Synaptobrevin VAMP1). Conversely, genes expressed in the PTF ring favor slower, sustained, or rhythmic activation (Sodium channels SCNA3

  15. Differences in Human Cortical Gene Expression Match the Temporal Properties of Large-Scale Functional Networks

    PubMed Central

    Cioli, Claudia; Abdi, Hervé; Beaton, Derek; Burnod, Yves; Mesmoudi, Salma

    2014-01-01

    We explore the relationships between the cortex functional organization and genetic expression (as provided by the Allen Human Brain Atlas). Previous work suggests that functional cortical networks (resting state and task based) are organized as two large networks (differentiated by their preferred information processing mode) shaped like two rings. The first ring–Visual-Sensorimotor-Auditory (VSA)–comprises visual, auditory, somatosensory, and motor cortices that process real time world interactions. The second ring–Parieto-Temporo-Frontal (PTF)–comprises parietal, temporal, and frontal regions with networks dedicated to cognitive functions, emotions, biological needs, and internally driven rhythms. We found–with correspondence analysis–that the patterns of expression of the 938 genes most differentially expressed across the cortex organized the cortex into two sets of regions that match the two rings. We confirmed this result using discriminant correspondence analysis by showing that the genetic profiles of cortical regions can reliably predict to what ring these regions belong. We found that several of the proteins–coded by genes that most differentiate the rings–were involved in neuronal information processing such as ionic channels and neurotransmitter release. The systematic study of families of genes revealed specific proteins within families preferentially expressed in each ring. The results showed strong congruence between the preferential expression of subsets of genes, temporal properties of the proteins they code, and the preferred processing modes of the rings. Ionic channels and release-related proteins more expressed in the VSA ring favor temporal precision of fast evoked neural transmission (Sodium channels SCNA1, SCNB1 potassium channel KCNA1, calcium channel CACNA2D2, Synaptotagmin SYT2, Complexin CPLX1, Synaptobrevin VAMP1). Conversely, genes expressed in the PTF ring favor slower, sustained, or rhythmic activation (Sodium

  16. Uncertainty of SWAT model at different DEM resolutions in a large mountainous watershed.

    PubMed

    Zhang, Peipei; Liu, Ruimin; Bao, Yimeng; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

    2014-04-15

    The objective of this study was to enhance understanding of the sensitivity of the SWAT model to the resolutions of Digital Elevation Models (DEMs) based on the analysis of multiple evaluation indicators. The Xiangxi River, a large tributary of Three Gorges Reservoir in China, was selected as the study area. A range of 17 DEM spatial resolutions, from 30 to 1000 m, was examined, and the annual and monthly model outputs based on each resolution were compared. The following results were obtained: (i) sediment yield was greatly affected by DEM resolution; (ii) the prediction of dissolved oxygen load was significantly affected by DEM resolutions coarser than 500 m; (iii) Total Nitrogen (TN) load was not greatly affected by the DEM resolution; (iv) Nitrate Nitrogen (NO₃-N) and Total Phosphorus (TP) loads were slightly affected by the DEM resolution; and (v) flow and Ammonia Nitrogen (NH₄-N) load were essentially unaffected by the DEM resolution. The flow and dissolved oxygen load decreased more significantly in the dry season than in the wet and normal seasons. Excluding flow and dissolved oxygen, the uncertainties of the other Hydrology/Non-point Source (H/NPS) pollution indicators were greater in the wet season than in the dry and normal seasons. Considering the temporal distribution uncertainties, the optimal DEM resolutions for flow was 30-200 m, for sediment and TP was 30-100 m, for dissolved oxygen and NO₃-N was 30-300 m, for NH₄-N was 30 to 70 m and for TN was 30-150 m. PMID:24509347

  17. Sex differences in event-related potentials and attentional biases to emotional facial stimuli

    PubMed Central

    Pfabigan, Daniela M.; Lamplmayr-Kragl, Elisabeth; Pintzinger, Nina M.; Sailer, Uta; Tran, Ulrich S.

    2014-01-01

    Attentional processes play an important role in the processing of emotional information. Previous research reported attentional biases during stimulus processing in anxiety and depression. However, sex differences in the processing of emotional stimuli and higher prevalence rates of anxiety disorders among women, compared to men, suggest that attentional biases may also differ between the two sexes. The present study used a modified version of the dot probe task with happy, angry, and neutral facial stimuli to investigate the time course of attentional biases in healthy volunteers. Moreover, associations of attentional biases with alexithymia were examined on the behavioral and physiological level. Event-related potentials were measured while 21 participants (11 women) performed the task, utilizing also for the first time a difference wave approach in the analysis to highlight emotion-specific aspects. Women showed overall enhanced probe P1 amplitudes compared to men, in particular after rewarding facial stimuli. Using the difference wave approach, probe P1 amplitudes appeared specifically enhanced with regard to congruently presented happy facial stimuli among women, compared to men. Both methods yielded enhanced probe P1 amplitudes after presentation of the emotional stimulus in the left compared to the right visual hemifield. Probe P1 amplitudes correlated negatively with self-reported alexithymia, most of these correlations were only observable in women. Our results suggest that women orient their attention to a greater extent to facial stimuli than men and corroborate that alexithymia is a correlate of reduced emotional reactivity on a neuronal level. We recommend using a difference wave approach when addressing attentional processes of orientation and disengagement also in future studies. PMID:25566151

  18. Exploring the potential of UV-spectral luminescence on different types of stalagmites

    NASA Astrophysics Data System (ADS)

    Reichelmann, Dana F. C.; Tjallingii, Rik; Brummer, Geert-Jan A.; Fohlmeister, Jens; Schröder-Ritzrau, Andrea; Constantin, Silviu; Richter, Detlev K.; Scholz, Denis

    2015-04-01

    The application of UV- spectral luminescence scanning (UV-SLS) has become an established method to reconstruct river discharge and associated precipitation form coral records. The studies on coral cores have shown that relative variations of the green and blue intensities emitted after exposure by UV light are related with relative concentrations humic acids. We explore the potential of UV-SLS on 7 stalagmite samples originating from three caves with very different settings. Three of the selected stalagmites originate from the Cloşani Cave (Romania), two stalagmites from the Zoolithencave (Germany) and two stalagmites from the B7-Cave (Germany). All stalagmites were polished before scanning with the Avaatech core scanner at the NIOZ (Netherlands) using both UV and visual light. This scanner is equipped with a UV-LED light source and can continuously record the emitted UV-SLS with a CCD line-scan camera (~70m/pixel). Under visual light the stalagmites from Zoolithencave show fine laminations of lighter and darker brownish layers. Both samples from B7-Cave show several brownish detritus layers as well as milky parts, but also some dark/clear parts with a visible lamination. Finally, the stalagmites from Cloşani Cave are very different with one stalagmite showing alternating white and dark/clear lamination, while a second one is more or less completely clear and a third one showing brownish detritus layers as well as dark/clear and milky parts. Preliminary UV-SLS results reveal that the very clear stalagmite C09-2 from Cloşani Cave does not show any luminescence. Similarly, all brownish detritus layers in the different speleothems turn opaque, which proofs to be useful to detect hiatuses in speleothems. Furthermore, the whiter parts in the stalagmites B7-1, B7-7 (B7-Cave) and C09-1 (Cloşani Cave) show stronger luminescence than the darker/clearer parts. The stalagmite Stam-4 (Cloşani Cave) shows a clear lamination of alternating white and dark/clear layers, which

  19. Interannual variation in climate-potential net primary productivity relationships in differing ecosystems of California

    SciTech Connect

    Koch, G.W.; Randerson, J.T. )

    1994-06-01

    The seasonality and interannual variation in potential net primary production (NPP) were examined in differing vegetation types in California over three years of contrasting precipitation using co-registered maps of climate, vegetation, and 1km biweekly NDVI derived from high resolution satellite AVHRR data. Differences in seasonality of the vegetation types (annual grassland, chamise chaparral, deciduous oak woodland, and evergreen oak) were clearly evident and corresponded well to patterns observed in field studies. In years and locations having high precipitation the annual peak in NDVI occurred later in all vegetation classes. The annual sum of biweekly NDVI was correlated with annual precipitation in all vegetation types, although the slopes and intercepts of the regressions differed among types. Annual grassland showed the largest increase in sumNDVI per unit increase in total precipitation and most of the variation in grassland sumNDVI was explained by variation in autumn precipitation. In general the ratio of sumNDVI to annual precipitation was dependent on the temporal distribution of precipitation with respect to the long-term average pattern. Published relationships between precipitation and NPP were used to develop equations relating annual NDVI sum to NPP.

  20. Mechanistic differences between methanol and dimethyl ether carbonylation in side pockets and large channels of mordenite.

    PubMed

    Boronat, Mercedes; Martínez, Cristina; Corma, Avelino

    2011-02-21

    The activity and selectivity towards carbonylation presented by Brønsted acid sites located inside the 8MR pockets or in the main 12MR channels of mordenite is studied by means of quantum-chemical calculations, and the mechanistic differences between methanol and DME carbonylation are investigated. The selectivity towards carbonylation is higher inside the 8MR pockets, where the competitive formation of DME and hydrocarbons that finally leads to catalyst deactivation is sterically impeded. Moreover, inclusion of dispersion interactions in the calculations leads to agreement between the calculated activation barriers for the rate determining step and the experimentally observed higher reactivity of methoxy groups located inside the 8MR channels. PMID:21249237

  1. Finite element-finite difference thermal/structural analysis of large space truss structures

    NASA Technical Reports Server (NTRS)

    Warren, Andrew H.; Arelt, Joseph E.; Eskew, William F.; Rogers, Karen M.

    1992-01-01

    A technique of automated and efficient thermal-structural processing of truss structures that interfaces the finite element and finite difference method was developed. The thermal-structural analysis tasks include development of the thermal and structural math models, thermal analysis, development of an interface and data transfer between the models, and finally an evaluation of the thermal stresses and displacements in the structure. Consequently, the objective of the developed technique was to minimize the model development time, in order to assure an automatic transfer of data between the thermal and structural models as well as to minimize the computer resources needed for the analysis itself. The method and techniques described are illustrated on the thermal/structural analysis of the Space Station Freedom main truss.

  2. Chromatin organization and cytological features of carnivorous Genlisea species with large genome size differences

    PubMed Central

    Tran, Trung D.; Cao, Hieu X.; Jovtchev, Gabriele; Novák, Petr; Vu, Giang T. H.; Macas, Jiří; Schubert, Ingo; Fuchs, Joerg

    2015-01-01

    The monophyletic carnivorous genus Genlisea (Lentibulariaceae) is characterized by a bi-directional genome size evolution resulting in a 25-fold difference in nuclear DNA content. This is one of the largest ranges found within a genus so far and makes Genlisea an interesting subject to study mechanisms of genome and karyotype evolution. Genlisea nigrocaulis, with 86 Mbp one of the smallest plant genomes, and the 18-fold larger genome of G. hispidula (1,550 Mbp) possess identical chromosome numbers (2n = 40) but differ considerably in chromatin organization, nuclear and cell size. Interphase nuclei of G. nigrocaulis and of related species with small genomes, G. aurea (133 Mbp, 2n ≈ 104) and G. pygmaea (179 Mbp, 2n = 80), are hallmarked by intensely DAPI-stained chromocenters, carrying typical heterochromatin-associated methylation marks (5-methylcytosine, H3K9me2), while in G. hispidula and surprisingly also in the small genome of G. margaretae (184 Mbp, 2n = 38) the heterochromatin marks are more evenly distributed. Probes of tandem repetitive sequences together with rDNA allow the unequivocal discrimination of 13 out of 20 chromosome pairs of G. hispidula. One of the repetitive sequences labeled half of the chromosome set almost homogenously supporting an allopolyploid status of G. hispidula and its close relative G. subglabra (1,622 Mbp, 2n = 40). In G. nigrocaulis 11 chromosome pairs could be individualized using a combination of rDNA and unique genomic probes. The presented data provide a basis for future studies of karyotype evolution within the genus Genlisea. PMID:26347752

  3. Chromatin organization and cytological features of carnivorous Genlisea species with large genome size differences.

    PubMed

    Tran, Trung D; Cao, Hieu X; Jovtchev, Gabriele; Novák, Petr; Vu, Giang T H; Macas, Jiří; Schubert, Ingo; Fuchs, Joerg

    2015-01-01

    The monophyletic carnivorous genus Genlisea (Lentibulariaceae) is characterized by a bi-directional genome size evolution resulting in a 25-fold difference in nuclear DNA content. This is one of the largest ranges found within a genus so far and makes Genlisea an interesting subject to study mechanisms of genome and karyotype evolution. Genlisea nigrocaulis, with 86 Mbp one of the smallest plant genomes, and the 18-fold larger genome of G. hispidula (1,550 Mbp) possess identical chromosome numbers (2n = 40) but differ considerably in chromatin organization, nuclear and cell size. Interphase nuclei of G. nigrocaulis and of related species with small genomes, G. aurea (133 Mbp, 2n ≈ 104) and G. pygmaea (179 Mbp, 2n = 80), are hallmarked by intensely DAPI-stained chromocenters, carrying typical heterochromatin-associated methylation marks (5-methylcytosine, H3K9me2), while in G. hispidula and surprisingly also in the small genome of G. margaretae (184 Mbp, 2n = 38) the heterochromatin marks are more evenly distributed. Probes of tandem repetitive sequences together with rDNA allow the unequivocal discrimination of 13 out of 20 chromosome pairs of G. hispidula. One of the repetitive sequences labeled half of the chromosome set almost homogenously supporting an allopolyploid status of G. hispidula and its close relative G. subglabra (1,622 Mbp, 2n = 40). In G. nigrocaulis 11 chromosome pairs could be individualized using a combination of rDNA and unique genomic probes. The presented data provide a basis for future studies of karyotype evolution within the genus Genlisea. PMID:26347752

  4. Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland

    USGS Publications Warehouse

    Watt, B.E.; Malcolm, R.L.; Hayes, M.H.B.; Clark, N.W.E.; Chipman, J.K.

    1996-01-01

    Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated and fractionated into humic acids (HA), fulvic acids (FA) and XAD-4 acids using columns of XAD-8 and of XAD-4 resins in tandem, and the fractions from the different sources were chlorinated and assayed for mutagenicity. CPMAS 13C NMR spectroscopy showed marked differences in compositions not only between HA, FA, and XAD-4 acids from the same water samples, but also between the same fractions from water samples from different watersheds. There were found to be strong similarities between the fractions from watersheds which had closely related soil types. Aromaticity was greatest in HAs, and lowest in XAD-4 acids, and carboxyl contents and aliphatic character were greatest in the XAD-4 acids. Carbon content decreased in the order HA > FA > XAD-4 acids, and amino acids and neutral sugars contents decreased in the order HA > XAD-4 > FA. Titration data complemented aspects of the NMR data, demonstrating that carboxyl content decreased in the order XAD-4 acids > FA > HA, and indicated that phenolic character was highest in HAs and lowest in the XAD-4 acids. All samples tested gave rise to bacterial mutagens on chlorination. Although the mutagenicities were of the same order of magnitude for the chlorinated humic samples from the different sources, the samples which showed the greatest number of revertant bacterial colonies were from the Thames and Trent, large rivers with humic materials from diverse environments, and relatively high in amino acid contents.

  5. Benthic ammonia oxidizers differ in community structure and biogeochemical potential across a riverine delta.

    PubMed

    Damashek, Julian; Smith, Jason M; Mosier, Annika C; Francis, Christopher A

    2014-01-01

    Nitrogen pollution in coastal zones is a widespread issue, particularly in ecosystems with urban or agricultural watersheds. California's Sacramento-San Joaquin Delta, at the landward reaches of San Francisco Bay, is highly impacted by both agricultural runoff and sewage effluent, leading to chronically high nutrient loadings. In particular, the extensive discharge of ammonium into the Sacramento River has altered this ecosystem by vastly increasing ammonium concentrations and thus changing the stoichiometry of inorganic nitrogen stocks, with potential effects throughout the food web. This debate surrounding ammonium inputs highlights the importance of understanding the rates of, and controls on, nitrogen (N) cycling processes across the delta. To date, however, there has been little research examining N biogeochemistry or N-cycling microbial communities in this system. We report the first data on benthic ammonia-oxidizing microbial communities and potential nitrification rates for the Sacramento-San Joaquin Delta, focusing on the functional gene amoA (which codes for the α-subunit of ammonia monooxygenase). There were stark regional differences in ammonia-oxidizing communities, with ammonia-oxidizing bacteria (AOB) outnumbering ammonia-oxidizing archaea (AOA) only in the ammonium-rich Sacramento River. High potential nitrification rates in the Sacramento River suggested these communities may be capable of oxidizing significant amounts of ammonium, compared to the San Joaquin River and the upper reaches of San Francisco Bay. Gene diversity also showed regional patterns, as well as phylogenetically unique ammonia oxidizers in the Sacramento River. The benthic ammonia oxidizers in this nutrient-rich aquatic ecosystem may be important players in its overall nutrient cycling, and their community structure and biogeochemical function appear related to nutrient loadings. Unraveling the microbial ecology and biogeochemistry of N cycling pathways, including benthic

  6. An Application of the Difference Potentials Method to Solving External Problems in CFD

    NASA Technical Reports Server (NTRS)

    Ryaben 'Kii, Victor S.; Tsynkov, Semyon V.

    1997-01-01

    Numerical solution of infinite-domain boundary-value problems requires some special techniques that would make the problem available for treatment on the computer. Indeed, the problem must be discretized in a way that the computer operates with only finite amount of information. Therefore, the original infinite-domain formulation must be altered and/or augmented so that on one hand the solution is not changed (or changed slightly) and on the other hand the finite discrete formulation becomes available. One widely used approach to constructing such discretizations consists of truncating the unbounded original domain and then setting the artificial boundary conditions (ABC's) at the newly formed external boundary. The role of the ABC's is to close the truncated problem and at the same time to ensure that the solution found inside the finite computational domain would be maximally close to (in the ideal case, exactly the same as) the corresponding fragment of the original infinite-domain solution. Let us emphasize that the proper treatment of artificial boundaries may have a profound impact on the overall quality and performance of numerical algorithms. The latter statement is corroborated by the numerous computational experiments and especially concerns the area of CFD, in which external problems present a wide class of practically important formulations. In this paper, we review some work that has been done over the recent years on constructing highly accurate nonlocal ABC's for calculation of compressible external flows. The approach is based on implementation of the generalized potentials and pseudodifferential boundary projection operators analogous to those proposed first by Calderon. The difference potentials method (DPM) by Ryaben'kii is used for the effective computation of the generalized potentials and projections. The resulting ABC's clearly outperform the existing methods from the standpoints of accuracy and robustness, in many cases noticeably speed up

  7. Wavelet analysis of corneal endothelial electrical potential difference reveals cyclic operation of the secretory mechanism

    NASA Astrophysics Data System (ADS)

    Cacace, V. I.; Montalbetti, N.; Kusnier, C.; Gomez, M. P.; Fischbarg, J.

    2011-09-01

    The corneal endothelium is a fluid-transporting epithelium. As other similar tissues, it displays an electrical potential of ˜1 mV (aqueous side negative) across the entire layer [transendothelial potential difference (TEPD)]. It appears that this electrical potential is mainly the result of the transport of anions across the cell layer (from stroma to aqueous). There is substantial evidence that the TEPD is related linearly to fluid transport; hence, under proper conditions, its measure could serve as a measure of fluid transport. Furthermore, the TEPD is not steady; instead, it displays a spectrum of frequency components (0-15 Hz) recognized recently using Fourier transforms. Such frequency components appear due to charge-separating (electrogenic) processes mediated by epithelial plasma membrane proteins (both ionic channels and ionic cotransporters). In particular, the endothelial TEPD oscillations of the highest amplitude (1-2 Hz) were linked to the operation of so-called sodium bicarbonate cotransporters. However, no time localization of that activity could be obtained with the Fourier methodology utilized. For that reason we now characterize the TEPD using wavelet analysis with the aim to localize in time the variations in TEPD. We find that the mentioned high-amplitude oscillatory components of the TEPD appear cyclically during the several hours that an endothelial preparation survives in vitro. They have a period of 4.6 ± 0.4 s on average (n=4). The wavelet power value at the peak of such oscillations is 1.5 ± 0.1 mV2 Hz on average (n = 4), and is remarkably narrow in its distribution.

  8. Benthic ammonia oxidizers differ in community structure and biogeochemical potential across a riverine delta

    PubMed Central

    Damashek, Julian; Smith, Jason M.; Mosier, Annika C.; Francis, Christopher A.

    2015-01-01

    Nitrogen pollution in coastal zones is a widespread issue, particularly in ecosystems with urban or agricultural watersheds. California's Sacramento-San Joaquin Delta, at the landward reaches of San Francisco Bay, is highly impacted by both agricultural runoff and sewage effluent, leading to chronically high nutrient loadings. In particular, the extensive discharge of ammonium into the Sacramento River has altered this ecosystem by vastly increasing ammonium concentrations and thus changing the stoichiometry of inorganic nitrogen stocks, with potential effects throughout the food web. This debate surrounding ammonium inputs highlights the importance of understanding the rates of, and controls on, nitrogen (N) cycling processes across the delta. To date, however, there has been little research examining N biogeochemistry or N-cycling microbial communities in this system. We report the first data on benthic ammonia-oxidizing microbial communities and potential nitrification rates for the Sacramento-San Joaquin Delta, focusing on the functional gene amoA (which codes for the α-subunit of ammonia monooxygenase). There were stark regional differences in ammonia-oxidizing communities, with ammonia-oxidizing bacteria (AOB) outnumbering ammonia-oxidizing archaea (AOA) only in the ammonium-rich Sacramento River. High potential nitrification rates in the Sacramento River suggested these communities may be capable of oxidizing significant amounts of ammonium, compared to the San Joaquin River and the upper reaches of San Francisco Bay. Gene diversity also showed regional patterns, as well as phylogenetically unique ammonia oxidizers in the Sacramento River. The benthic ammonia oxidizers in this nutrient-rich aquatic ecosystem may be important players in its overall nutrient cycling, and their community structure and biogeochemical function appear related to nutrient loadings. Unraveling the microbial ecology and biogeochemistry of N cycling pathways, including benthic

  9. Patterns in benthic biodiversity link lake trophic status to structure and potential function of three large, deep lakes.

    PubMed

    Hayford, Barbara L; Caires, Andrea M; Chandra, Sudeep; Girdner, Scott F

    2015-01-01

    Relative to their scarcity, large, deep lakes support a large proportion of the world's freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world's largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe's diversity is indicative of differential response of chironomid

  10. Effect of glucagon and pentagastrin on gastric mucosal potential difference in man.

    PubMed Central

    Tarnawski, A; Ivey, K J; McGuigan, J E; England, J

    1978-01-01

    Glucagon given as an intravenous injection of 2 mg (0.57 mmol) or as constant intravenous infusion of 1.64 microgram/kg/h (0.47 nmol/kg/h) significantly increased gastric mucosal potential difference (PD) in man. Pentagastrin infusion of 2 microgram/kg/h (2.8 nmol/kg/h) dramatically reduced gastric PD in man. The effect of each of these hormones on PD was reversed by the administration of the other. Changes in PD induced by one hormone were not associated with reductions in blood levels of the other. There was an approximate correlation between changes in PD and pH of gastric aspirates, however, the patterns of PD and pH changes were at times dissimilar. This study indicates that administration of gastrointestinal hormones significantly alters gastric mucosal PD in man. PMID:33874

  11. [The significance of sex-linked differences for the assessment of somatosensory evoked potentials (author's transl)].

    PubMed

    Strenge, H; Hedderich, J; Tackmann, W

    1981-09-01

    In 45 healthy volunteers (22 males and 23 females with the same age structure) the peak latencies and inter-peak differences of the cervical and early cortical components of the somatosensory evoked potential were measured. The distribution of the values of the variables and their relationship with arm length were investigated both for the sample as a whole and for each sex separately. Significantly higher average values of the latencies and arm lengths were found in men. The correlations between arm length and latency had consistently higher values for the female sample. On the basis of these results it is concluded that a sufficient assessment of the latencies is only possible with the help of sex-specific normal values. PMID:6795015

  12. Differences Between Synaptic Plasticity Thresholds Result in New Timing Rules for Maximizing Long-Term Potentiation

    PubMed Central

    Lynch, Gary; Kramár, Enikö A.; Babayan, Alex H.; Rumbaugh, Gavin; Gall, Christine M.

    2012-01-01

    The fundamental observation that the temporal spacing of learning episodes plays a critical role in the efficiency of memory encoding has had little effect on either research on long-term potentiation (LTP) or efforts to develop cognitive enhancers. Here we review recent findings describing a spaced trials phenomenon for LTP that appears to be related to recent evidence that plasticity thresholds differ between synapses in the adult hippocampus. Results of tests with one memory enhancing drug suggest that the compound potently facilitates LTP via effects on high threshold synapses and thus alters the temporally extended timing rules. Possible implications of these results for our understanding of LTP substrates, neurobiological contributors to the distributed practice effect, and the consequences of memory enhancement are discussed. PMID:22820276

  13. Primary task event-related potentials related to different aspects of information processing

    NASA Technical Reports Server (NTRS)

    Munson, Robert C.; Horst, Richard L.; Mahaffey, David L.

    1988-01-01

    The results of two studies which investigated the relationships between cognitive processing and components of transient event-related potentials (ERPs) are presented in a task in which mental workload was manipulated. The task involved the monitoring of an array of discrete readouts for values that went out of bounds, and was somewhat analogous to tasks performed in cockpits. The ERPs elicited by the changing readouts varied with the number of readouts being monitored, the number of monitored readouts that were close to going out of bounds, and whether or not the change took a monitored readout out of bounds. Moreover, different regions of the waveform differentially reflected these effects. The results confirm the sensitivity of scalp-recorded ERPs to the cognitive processes affected by mental workload and suggest the possibility of extracting useful ERP indices of primary task performance in a wide range of man-machine settings.

  14. Organic nanoparticles from different fuel blends: in vitro toxicity and inflammatory potential.

    PubMed

    Gualtieri, Maurizio; Capasso, Laura; D'Anna, Andrea; Camatini, Marina

    2014-11-01

    Despite the well-established link between particulate vehicle emissions and adverse health effects, the biological effects produced by ultrafine particles generated from fuel combustion need to be investigated. The biological impact of nano-sized organic carbon particles in the size range 3-7 nm, obtained from an engine fuelled with a standard diesel and four diesel fuels doped with additives of commercial interest is reported. Our data showed that the number of particles < 10 nm is to a very small extent reduced by diesel particle filters, despite its ability to trap micrometric and submicrometric particulates, and that there is a correlation between the additives used and the chemical characteristics of the nanoparticles sampled. The results show that the different nano-sized organic carbon particles induce cytotoxic and proinflammatory effects on the in vitro systems A549 (epithelial cells) and BEAS-2B (bronchial cells). All the fuels tested are able to induce the release of proinflammatory interleukins 8 and 6; moreover, the IC50 values show that the additives can increase the toxic potential of particles 10 times. Further analyses are therefore needed to better define the potential impact of organic ultrafine particles on human health. PMID:25244046

  15. Different Representations of Potential and Selected Motor Plans by Distinct Parietal Areas

    PubMed Central

    Cui, He; Andersen, Richard A.

    2012-01-01

    Traditional theories have considered decision making as a separate neural process occurring before action planning. However, recent neurophysiological studies of spatial target selection have suggested that decision making and motor planning may be performed in an integrated manner. It was proposed that multiple potential plans are concurrently formed and the ultimately selected action simultaneously emerges within the same circuits (e.g., Cisek and Kalaska, 2010; Shadlen and Newsome, 2001). In the present study, we recorded from the parietal reach region (PRR) and dorsal area 5 (area 5d) in the posterior parietal cortex (PPC) while monkeys performed a non-spatial effector (saccade vs reach) choice task. The results show that PRR encodes potential and selected reach plans whereas area 5d encodes only selected reach plans, suggesting a serial visuomotor cortical circuitry for non-spatial effector decisions. Thus, there appears to be a different flow of processing for decisions and planning for spatial target selection, which is more integrated, and non-spatial effector decisions between eye and limb movements, which are more serial. PMID:22159124

  16. Kinetic equivalence of transmembrane pH and electrical potential differences in ATP synthesis.

    PubMed

    Soga, Naoki; Kinosita, Kazuhiko; Yoshida, Masasuke; Suzuki, Toshiharu

    2012-03-16

    ATP synthase is the key player of Mitchell's chemiosmotic theory, converting the energy of transmembrane proton flow into the high energy bond between ADP and phosphate. The proton motive force that drives this reaction consists of two components, the pH difference (ΔpH) across the membrane and transmembrane electrical potential (Δψ). The two are considered thermodynamically equivalent, but kinetic equivalence in the actual ATP synthesis is not warranted, and previous experimental results vary. Here, we show that with the thermophilic Bacillus PS3 ATP synthase that lacks an inhibitory domain of the ε subunit, ΔpH imposed by acid-base transition and Δψ produced by valinomycin-mediated K(+) diffusion potential contribute equally to the rate of ATP synthesis within the experimental range examined (ΔpH -0.3 to 2.2, Δψ -30 to 140 mV, pH around the catalytic domain 8.0). Either ΔpH or Δψ alone can drive synthesis, even when the other slightly opposes. Δψ was estimated from the Nernst equation, which appeared valid down to 1 mm K(+) inside the proteoliposomes, due to careful removal of K(+) from the lipid. PMID:22253434

  17. In vitro evaluation of UV opacity potential of Aloe vera L. gel from different germplasms.

    PubMed

    Kumar, M Shyam; Datta, P K; Dutta Gupta, S

    2009-04-01

    In this study, lyophilized crude and methanolic extracts of aloe gel from different germplasms (S24, RM, TN, OR, and RJN) of Aloe vera L. were tested for their ultraviolet (UV) opacity potential. UV absorption profiles, sun protection factor (SPF), and percentage blocking of UVA and UVB were considered to test UV opacity potential. Both the extracts showed UV absorption and followed the same path in the wavelength range of 250-400 nm in all the germplasms. Methanolic extract showed a stronger absorptivity than the crude lyophilized extract. Among the tested germplasms, maximum UV opacity property with a SPF of 9.97% and 79.12% UVB blocking was obtained with RJN, whereas a poor response was evident in TN with a SPF of 1.37% and 28.5% UVB blocking at 4 mg/ml methanolic extract. To our knowledge the present work for the first time documents UV opacity properties of A. vera L. gel and opens up new vistas in Aloe gel characterization. PMID:19034609

  18. Comparing the Biogeochemical Potential of Hyporheic Zones Driven by Different River Morphologies

    NASA Astrophysics Data System (ADS)

    Gomez, J. D.; Harvey, J. W.

    2013-12-01

    Channel morphology controls the hydrodynamics of hyporheic exchange and its residence times. As a result, it also constrains the hyporheic zone's biogeochemical processes that transform carbon, nutrients, metals, and contaminants and the hyporheic zone's net effect at the local, reach and watershed scales. Previous studies of different morphologies (e.g., meanders, bars, and smaller bedforms such as dunes) have mainly focused on the amount of exchange or, if biogeochemistry was involved, have been specific to a particular morphology. In this work, we present a quantitative intercomparison of the amount of exchange, residence time distributions (RTDs), and biogeochemical potential for four channel morphologies: ripples, dunes, bars, and meander bends. To this end, simple two-dimensional conceptualizations and semi-analytical solutions for the hyporheic zone's flow and transport are used. In general, all morphologies are characterized by heavy-tail RTDs, implying long-term memory to solute inputs. We hypothesize that even though meander bends induce larger hyporheic exchange per unit length of channel and longer residence times, substrate limitations result in less biogeochemical processing when compared with the cumulative effect of multiple bedforms. The models presented are a function of geometric and physical properties easily measured or constrained with field or remote sensing data. The simplicity of this approach allows for practical calculations of the hyporheic zone's exchange and biogeochemical potential over a broad range of scenarios and morphologies, making it a useful tool for experimental design, sampling, and watershed scale assessment.

  19. Betavoltaic effect in titanium dioxide nanotube arrays under build-in potential difference

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Chen, Ranbin; San, Haisheng; Liu, Guohua; Wang, Kaiying

    2015-05-01

    We report the fabrication of sandwich-type metal/TiO2 nanotube (TNT) array/metal structures as well as their betavoltaic effects under build-in voltage through contact potential difference. The sandwiched structure is integrated by immobilized TNT arrays on Ti foil with radioisotope 63Ni planar source on Ni substrate (Ni-63Ni/TNT array/Ti). Under irradiation of the 63Ni source with activity of 8 mCi, the structure (TNT diameter ∼ 130 nm, length ∼ 11 μm) presents optimum energy conversion efficiency of 7.30% with open-circuit voltage of 1.54 V and short-circuit current of 12.43 nA. The TNT arrays exhibit a highly potential for developing betavoltaic batteries due to its wide band gap and nanotube array configuration. The TNT-betavoltaic concept offers a facile solution for micro/nano electronics with high efficiency and long life-time instead of conventional planar junction-type batteries.

  20. Effects of differing purified cellulose, pectin and hemicellulose fiber diets on mucosal morphology in the rat small and large intestine.

    PubMed

    Dirks, P; Freeman, H J

    1987-01-01

    The effects of increasing amounts of differing single-fiber sources in chemically-defined and nutritionally-equivalent diets on morphometric measurements of the rat small and large intestinal mucosa were examined. Male Wistar rats received a fiber-free diet, or diets containing 4.5% or 9.0% cellulose, pectin, or hemicellulose. Cellulose and pectin increased jejunal (but not ileal) villus and crypt heights, whereas hemicellulose increased ileal (but not jejunal) mucosal height. Moreover, cellulose and pectin (but not hemicellulose) increased crypt heights in cecum and proximal (but not distal) colon. Parallel increases in the mitotic index were seen with cellulose and pectin diets, but there was a decrease with hemicellulose, suggesting different mechanisms for altered patterns of cell renewal induced by orally-administered single-fiber sources. These changes indicate that differing single-fiber sources exert differential structural effects along the length of the small and large intestine in the rat. PMID:3028682

  1. Sex Differences in Kappa Opioid Receptor Function and Their Potential Impact on Addiction

    PubMed Central

    Chartoff, Elena H.; Mavrikaki, Maria

    2015-01-01

    Behavioral, biological, and social sequelae that lead to drug addiction differ between men and women. Our efforts to understand addiction on a mechanistic level must include studies in both males and females. Stress, anxiety, and depression are tightly linked to addiction, and whether they precede or result from compulsive drug use depends on many factors, including biological sex. The neuropeptide dynorphin (DYN), an endogenous ligand at kappa opioid receptors (KORs), is necessary for stress-induced aversive states and is upregulated in the brain after chronic exposure to drugs of abuse. KOR agonists produce signs of anxiety, fear, and depression in laboratory animals and humans, findings that have led to the hypothesis that drug withdrawal-induced DYN release is instrumental in negative reinforcement processes that drive addiction. However, these studies were almost exclusively conducted in males. Only recently is evidence available that there are sex differences in the effects of KOR activation on affective state. This review focuses on sex differences in DYN and KOR systems and how these might contribute to sex differences in addictive behavior. Much of what is known about how biological sex influences KOR systems is from research on pain systems. The basic molecular and genetic mechanisms that have been discovered to underlie sex differences in KOR function in pain systems may apply to sex differences in KOR function in reward systems. Our goals are to discuss the current state of knowledge on how biological sex contributes to KOR function in the context of pain, mood, and addiction and to explore potential mechanisms for sex differences in KOR function. We will highlight evidence that the function of DYN-KOR systems is influenced in a sex-dependent manner by: polymorphisms in the prodynorphin (pDYN) gene, genetic linkage with the melanocortin-1 receptor (MC1R), heterodimerization of KORs and mu opioid receptors (MORs), and gonadal hormones. Finally, we

  2. Potential Distribution Predicted for Rhynchophorus ferrugineus in China under Different Climate Warming Scenarios.

    PubMed

    Ge, Xuezhen; He, Shanyong; Wang, Tao; Yan, Wei; Zong, Shixiang

    2015-01-01

    As the primary pest of palm trees, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) has caused serious harm to palms since it first invaded China. The present study used CLIMEX 1.1 to predict the potential distribution of R. ferrugineus in China according to both current climate data (1981-2010) and future climate warming estimates based on simulated climate data for the 2020s (2011-2040) provided by the Tyndall Center for Climate Change Research (TYN SC 2.0). Additionally, the Ecoclimatic Index (EI) values calculated for different climatic conditions (current and future, as simulated by the B2 scenario) were compared. Areas with a suitable climate for R. ferrugineus distribution were located primarily in central China according to the current climate data, with the northern boundary of the distribution reaching to 40.1°N and including Tibet, north Sichuan, central Shaanxi, south Shanxi, and east Hebei. There was little difference in the potential distribution predicted by the four emission scenarios according to future climate warming estimates. The primary prediction under future climate warming models was that, compared with the current climate model, the number of highly favorable habitats would increase significantly and expand into northern China, whereas the number of both favorable and marginally favorable habitats would decrease. Contrast analysis of EI values suggested that climate change and the density of site distribution were the main effectors of the changes in EI values. These results will help to improve control measures, prevent the spread of this pest, and revise the targeted quarantine areas. PMID:26496438

  3. Potential Distribution Predicted for Rhynchophorus ferrugineus in China under Different Climate Warming Scenarios

    PubMed Central

    Ge, Xuezhen; He, Shanyong; Wang, Tao; Yan, Wei; Zong, Shixiang

    2015-01-01

    As the primary pest of palm trees, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) has caused serious harm to palms since it first invaded China. The present study used CLIMEX 1.1 to predict the potential distribution of R. ferrugineus in China according to both current climate data (1981–2010) and future climate warming estimates based on simulated climate data for the 2020s (2011–2040) provided by the Tyndall Center for Climate Change Research (TYN SC 2.0). Additionally, the Ecoclimatic Index (EI) values calculated for different climatic conditions (current and future, as simulated by the B2 scenario) were compared. Areas with a suitable climate for R. ferrugineus distribution were located primarily in central China according to the current climate data, with the northern boundary of the distribution reaching to 40.1°N and including Tibet, north Sichuan, central Shaanxi, south Shanxi, and east Hebei. There was little difference in the potential distribution predicted by the four emission scenarios according to future climate warming estimates. The primary prediction under future climate warming models was that, compared with the current climate model, the number of highly favorable habitats would increase significantly and expand into northern China, whereas the number of both favorable and marginally favorable habitats would decrease. Contrast analysis of EI values suggested that climate change and the density of site distribution were the main effectors of the changes in EI values. These results will help to improve control measures, prevent the spread of this pest, and revise the targeted quarantine areas. PMID:26496438

  4. A Large Gene Cluster Encoding Several Magnetosome Proteins Is Conserved in Different Species of Magnetotactic Bacteria

    PubMed Central

    Grünberg, Karen; Wawer, Cathrin; Tebo, Bradley M.; Schüler, Dirk

    2001-01-01

    In magnetotactic bacteria, a number of specific proteins are associated with the magnetosome membrane (MM) and may have a crucial role in magnetite biomineralization. We have cloned and sequenced the genes of several of these polypeptides in the magnetotactic bacterium Magnetospirillum gryphiswaldense that could be assigned to two different genomic regions. Except for mamA, none of these genes have been previously reported to be related to magnetosome formation. Homologous genes were found in the genome sequences of M. magnetotacticum and magnetic coccus strain MC-1. The MM proteins identified display homology to tetratricopeptide repeat proteins (MamA), cation diffusion facilitators (MamB), and HtrA-like serine proteases (MamE) or bear no similarity to known proteins (MamC and MamD). A major gene cluster containing several magnetosome genes (including mamA and mamB) was found to be conserved in all three of the strains investigated. The mamAB cluster also contains additional genes that have no known homologs in any nonmagnetic organism, suggesting a specific role in magnetosome formation. PMID:11571158

  5. bZIPs and WRKYs: two large transcription factor families executing two different functional strategies

    PubMed Central

    Llorca, Carles M.; Potschin, Maren; Zentgraf, Ulrike

    2014-01-01

    bZIPs and WRKYs are two important plant transcription factor (TF) families regulating diverse developmental and stress-related processes. Since a partial overlap in these biological processes is obvious, it can be speculated that they fulfill non-redundant functions in a complex regulatory network. Here, we focus on the regulatory mechanisms that are so far described for bZIPs and WRKYs. bZIP factors need to heterodimerize for DNA-binding and regulation of transcription, and based on a bioinformatics approach, bZIPs can build up more than the double of protein interactions than WRKYs. In contrast, an enrichment of the WRKY DNA-binding motifs can be found in WRKY promoters, a phenomenon which is not observed for the bZIP family. Thus, the two TF families follow two different functional strategies in which WRKYs regulate each other’s transcription in a transcriptional network whereas bZIP action relies on intensive heterodimerization. PMID:24817872

  6. Channel formation during flushing of large shallow reservoirs with different geometries.

    PubMed

    Kantoush, Sameh A; Schleiss, Anton J

    2009-07-01

    Depositional and flow patterns are first described to gain an understanding of the erosion patterns during hydraulic flushing in a reservoir. Considering the importance of this issue, two modes of flushing operation for control of sedimentation were performed in several experiments with different reservoir geometries. In order to investigate the effect of flushing and the effectiveness during free and drawdown flows, ten experiments have been conducted. The final bed morphology formed previously was used as the initial bed topography for the two modes of flushing. The entire experiments lasted for two days. Investigations of the flow pattern and the associated bed topography for free flow with normal water depth and drawdown flushing in various shallow reservoir geometries are presented. To effectively apply the flushing processes for the removal of sediment deposits, the location, depth and width of the flushing channel can be changed by modifications to the reservoir geometry. The channel formed during flushing attracts the jet and stabilizes the flow structures over the entire surface. Empirical formulae to describe the relationship between the reservoir geometry and flushing efficiency for the two modes of flushing were developed. Flushing at normal water level allows only a relatively small part of the deposited sediment to be evacuated. As deposits could be flushed out of the basin. PMID:19705670

  7. Annual surveys of larval Ambystoma cingulatum reveal large differences in dates of pond residency

    SciTech Connect

    Bevelhimer, Mark S; Giffen, Neil R; Stevenson, Dirk

    2008-05-01

    Effective sampling of pond-dwelling larval stages of the federally listed Ambystoma cingulatum (Flatwoods Salamander) requires sufficient knowledge of when larvae are present and how best to sample them. Through systematic sampling with active and passive sampling techniques, we found dipnetting to be significantly more effective than three types of passive traps. During surveys for Flatwoods Salamander larvae at Fort Stewart Military Installation, GA in 2005 and 2006, we found that pond residency varied by at least 1.5 months between the 2 years due to the timing of pond filling. In addition, our latest capture on 23 May 2005 was about 2 weeks later than previously recorded at any site range-wide. A simple growth model was used to evaluate likely hatching dates based on significant rain events, observed sizes at capture, and likely growth rates. This analysis suggested that the primary dates of hatching occurred in late February 2005 and early January 2006, a difference that corresponds to that seen in the residency of the latest larval stages. A review of the survey records for Fort Stewart for the past 13 years shows a steep decline in the number of occupied ponds from near 20 to a single pond for the past two years (the only documented breeding success in a natural pond since 1999).

  8. Genetic potential of common bean progenies selected for crude fiber content obtained through different breeding methods.

    PubMed

    Júnior, V A P; Melo, P G S; Pereira, H S; Bassinello, P Z; Melo, L C

    2015-01-01

    Gastrointestinal health is of great importance due to the increasing consumption of functional foods, especially those concern-ing diets rich in fiber content. The common bean has been valorized as a nutritious food due to its appreciable fiber content and the fact that it is consumed in many countries. The current study aimed to evaluate and compare the genetic potential of common bean progenies of the carioca group, developed through different breeding methods, for crude fiber content. The progenies originated through hybridization of two advanced strains, CNFC 7812 and CNFC 7829, up to the F7 generation using three breeding methods: bulk-population, bulk within F2 families, and single seed descent. Fifteen F8 progenies were evaluated in each method, as well as two check cultivars and both parents, us-ing a 7 x 7 simple lattice design, with experimental plots comprised of two 4-m long rows. Field trials were conducted in eleven environments encompassing four Brazilian states and three different sowing times during 2009 and 2010. Estimates of genetic parameters indicate differences among the breeding methods, which seem to be related to the different processes for sampling the advanced progenies inherent to each method, given that the trait in question is not subject to natural selection. Variability amongst progenies occurred within the three breeding methods and there was also a significant effect of environment on the progeny for all methods. Progenies developed by bulk-population attained the highest estimates of genetic parameters, had less interaction with the environment, and greater variability. PMID:26125775

  9. Simulated environmental criticalities affect transglutaminase of Malus and Corylus pollens having different allergenic potential.

    PubMed

    Iorio, Rosa Anna; Di Sandro, Alessia; Paris, Roberta; Pagliarani, Giulia; Tartarini, Stefano; Ricci, Giampaolo; Serafini-Fracassini, Donatella; Verderio, Elisabetta; Del Duca, Stefano

    2012-02-01

    Increases in temperature and air pollution influence pollen allergenicity, which is responsible for the dramatic raise in respiratory allergies. To clarify possible underlying mechanisms, an anemophilous pollen (hazel, Corylus avellana), known to be allergenic, and an entomophilous one (apple, Malus domestica), the allergenicity of which was not known, were analysed. The presence also in apple pollen of known fruit allergens and their immunorecognition by serum of an allergic patient were preliminary ascertained, resulting also apple pollen potentially allergenic. Pollens were subjected to simulated stressful conditions, provided by changes in temperature, humidity, and copper and acid rain pollution. In the two pollens exposed to environmental criticalities, viability and germination were negatively affected and different transglutaminase (TGase) gel bands were differently immunodetected with the polyclonal antibody AtPng1p. The enzyme activity increased under stressful treatments and, along with its products, was found to be released outside the pollen with externalisation of TGase being predominant in C. avellana, whose grain presents a different cell wall composition with respect to that of M. domestica. A recombinant plant TGase (AtPng1p) stimulated the secreted phospholipase A(2) (sPLA(2)) activity, that in vivo is present in human mucosa and is involved in inflammation. Similarly, stressed pollen, hazel pollen being the most efficient, stimulated to very different extent sPLA(2) activity and putrescine conjugation to sPLA(2). We propose that externalised pollen TGase could be one of the mediators of pollen allergenicity, especially under environmental stress induced by climate changes. PMID:21847612

  10. Smart grid initialization reduces the computational complexity of multi-objective image registration based on a dual-dynamic transformation model to account for large anatomical differences

    NASA Astrophysics Data System (ADS)

    Bosman, Peter A. N.; Alderliesten, Tanja

    2016-03-01

    We recently demonstrated the strong potential of using dual-dynamic transformation models when tackling deformable image registration problems involving large anatomical differences. Dual-dynamic transformation models employ two moving grids instead of the common single moving grid for the target image (and single fixed grid for the source image). We previously employed powerful optimization algorithms to make use of the additional flexibility offered by a dual-dynamic transformation model with good results, directly obtaining insight into the trade-off between important registration objectives as a result of taking a multi-objective approach to optimization. However, optimization has so far been initialized using two regular grids, which still leaves a great potential of dual-dynamic transformation models untapped: a-priori grid alignment with image structures/areas that are expected to deform more. This allows (far) less grid points to be used, compared to using a sufficiently refined regular grid, leading to (far) more efficient optimization, or, equivalently, more accurate results using the same number of grid points. We study the implications of exploiting this potential by experimenting with two new smart grid initialization procedures: one manual expert-based and one automated image-feature-based. We consider a CT test case with large differences in bladder volume with and without a multi-resolution scheme and find a substantial benefit of using smart grid initialization.

  11. Potential near-future carbon uptake overcomes losses from a large insect outbreak in British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Arora, Vivek K.; Peng, Yiran; Kurz, Werner A.; Fyfe, John C.; Hawkins, Barbara; Werner, Arelia T.

    2016-03-01

    The current capacity of northern high-latitude forests to sequester carbon has been suggested to be undermined by the potential increase in fire and insect outbreaks. Here we investigate the response of the terrestrial ecosystems in the province of British Columbia (BC), Canada, to the recent large mountain pine beetle (MPB) outbreak that started in 1999 as well as changing climate and continually increasing atmospheric CO2 concentration up to 2050, in a combined framework, using a process-based model. Model simulations suggest that the recent MPB outbreak results in BC's forests accumulating 328 Tg less carbon over the 1999-2020 period. Over this same period changing climate and increasing atmospheric CO2 concentration, however, yield enhanced carbon uptake equal to a cumulative sink of around 900-1060 Tg C, depending on the future climate change scenario, indicating that the reduced carbon uptake by land due to the MPB disturbance may already be surpassed by 2020.

  12. Water content and matric potential of soil under different soil frost conditions

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Iwata, Y.; Hiirota, T.; Hasegawa, S.; Arima, J.

    2006-12-01

    Eastern Hokkaido, where is one of the largest agricultural production regions in Japan, is characterized by low air temperature and relatively thin snow covers resulting in soil frost over the winter. However, the soil frost depth has been significantly decreasing since late 1980's due to an insulation from the cold air by a thick snow cover developing in early winter. In the current study, soil water movement under different soil frost conditions were monitored to obtain a knowledge of changes in hydraulic-regime of the agricultural production systems in the Eastern Hokkaido associated with the decreasing soil frost depth in the region. A paired soil plot experiment was conducted from Nov. 2005 to May 2006, where the frost depth was artificially enhanced by removing snow in the treatment plot and the natural condition was maintained in the control plot. The soil in the experimental field was classified as Andisol with much porosity and high drainability. In each plot, water content and matric potential were measured by TDR and thermally-insulated tensiometer, respectively. Changes in snow water equivalent volume (SWE) and soil-frost depth were manually recorded. The maximum soil-frost depth in the treatment and control plots resulted in 47 and 19 cm, respectively. In both plots, soil water content and matric potential in underlying unfrozen soil decreased with the progress of freezing front, and the direction of soil water flow between 90 and 100 cm changed from downward to upward after the onset of the soil freezing. It is of note that the matric potential at 90 cm in the treatment plot decreased down to -480 cm, while the matric potential at the same depth in the control plot was -200 cm at minimum. When the underlying unfrozen soil was most driest the soil water volume stored in a depth interval from 50 to 100 cm for the treatment and control plots was 189 and 212 mm, respectively. Further, the magnitude of upward hydraulic gradient between 90 and 100 cm in the

  13. On the large deformation behaviour of reinforced rubber at different temperatures

    NASA Astrophysics Data System (ADS)

    Lion, Alexander

    1997-11-01

    This essay investigates the temperature dependence of the mechanical properties of a filler-loaded tread compound experimentally and proposes a physically based method to represent this behaviour in the framework of non-linear continuum thermomechanics. To this end, we realise a series of monotonic and cyclic strain controlled tests on cylindrical specimens in tension at different temperature levels. The experimental data show the isothermal mechanical behaviour to be mainly influenced by non-linear elasticity in combination with non-linear rate dependence and weak equilibrium hysteresis. We observe that the rate sensitivity of the material depends strongly on the temperature : at low temperature levels, the rate sensitivity is essentially higher than at high temperatures. The elastic properties of the material depend comparatively less on the temperature. Nevertheless, higher temperature levels lead to higher equilibrium stresses. In order to represent the material behaviour, we start with a multiplicative split of the deformation gradient into a mechanical and a thermal part as proposed by Lu and Pister (1975). Physically, this idea corresponds to a stress-free thermal expansion followed by an isothermal stress-producing deformation. We suppose the thermal part of the deformation gradient to be isotropic. As a consequence of this, the velocity gradient decomposes additively into a pure thermal and a pure mechanical part. By using these elements, we exploit the Clausius Duhem inequality and assume the so-called 'mechanical second Piola Kirchhoff stress tensor' to be a functional of the 'mechanical Green's strain tensor'. In a further step, we define this functional by a system of constitutive equations which are based on a rheological model. The evolution equations for the internal variables are formulated by using the concept of dual variables proposed by Haupt and Tsakmakis (1989, 1996). The rate sensitivity is modelled by a stress and temperature dependent

  14. On the formulation of gravitational potential difference between the GRACE satellites based on energy integral in Earth fixed frame

    NASA Astrophysics Data System (ADS)

    Zeng, Y. Y.; Guo, J. Y.; Shang, K.; Shum, C. K.; Yu, J. H.

    2015-09-01

    Two methods for computing gravitational potential difference (GPD) between the GRACE satellites using orbit data have been formulated based on energy integral; one in geocentric inertial frame (GIF) and another in Earth fixed frame (EFF). Here we present a rigorous theoretical formulation in EFF with particular emphasis on necessary approximations, provide a computational approach to mitigate the approximations to negligible level, and verify our approach using simulations. We conclude that a term neglected or ignored in all former work without verification should be retained. In our simulations, 2 cycle per revolution (CPR) errors are present in the GPD computed using our formulation, and empirical removal of the 2 CPR and lower frequency errors can improve the precisions of Stokes coefficients (SCs) of degree 3 and above by 1-2 orders of magnitudes. This is despite of the fact that the result without removing these errors is already accurate enough. Furthermore, the relation between data errors and their influences on GPD is analysed, and a formal examination is made on the possible precision that real GRACE data may attain. The result of removing 2 CPR errors may imply that, if not taken care of properly, the values of SCs computed by means of the energy integral method using real GRACE data may be seriously corrupted by aliasing errors from possibly very large 2 CPR errors based on two facts: (1) errors of bar C_{2,0} manifest as 2 CPR errors in GPD and (2) errors of bar C_{2,0} in GRACE data-the differences between the CSR monthly values of bar C_{2,0} independently determined using GRACE and SLR are a reasonable measure of their magnitude-are very large. Our simulations show that, if 2 CPR errors in GPD vary from day to day as much as those corresponding to errors of bar C_{2,0} from month to month, the aliasing errors of degree 15 and above SCs computed using a month's GPD data may attain a level comparable to the magnitude of gravitational potential

  15. Event-related potentials reveal the relations between feature representations at different levels of abstraction.

    PubMed

    Hannah, Samuel D; Shedden, Judith M; Brooks, Lee R; Grundy, John G

    2016-11-01

    In this paper, we use behavioural methods and event-related potentials (ERPs) to explore the relations between informational and instantiated features, as well as the relation between feature abstraction and rule type. Participants are trained to categorize two species of fictitious animals and then identify perceptually novel exemplars. Critically, two groups are given a perfectly predictive counting rule that, according to Hannah and Brooks (2009. Featuring familiarity: How a familiar feature instantiation influences categorization. Canadian Journal of Experimental Psychology/Revue Canadienne de Psychologie Expérimentale, 63, 263-275. Retrieved from http://doi.org/10.1037/a0017919), should orient them to using abstract informational features when categorizing the novel transfer items. A third group is taught a feature list rule, which should orient them to using detailed instantiated features. One counting-rule group were taught their rule before any exposure to the actual stimuli, and the other immediately after training, having learned the instantiations first. The feature-list group were also taught their rule after training. The ERP results suggest that at test, the two counting-rule groups processed items differently, despite their identical rule. This not only supports the distinction that informational and instantiated features are qualitatively different feature representations, but also implies that rules can readily operate over concrete inputs, in contradiction to traditional approaches that assume that rules necessarily act on abstract inputs. PMID:26513169

  16. Hemispheric differences in orthographic and semantic processing as revealed by event-related potentials

    PubMed Central

    Dickson, Danielle S.; Federmeier, Kara D.

    2015-01-01

    Differences in how the right and left hemispheres (RH, LH) apprehend visual words were examined using event-related potentials (ERPs) in a repetition paradigm with visual half-field (VF) presentation. In both hemispheres (RH/LVF, LH/RVF), initial presentation of items elicited similar and typical effects of orthographic neighborhood size, with larger N400s for orthographically regular items (words and pseudowords) than for irregular items (acronyms and meaningless illegal strings). However, hemispheric differences emerged on repetition effects. When items were repeated in the LH/RVF, orthographically regular items, relative to irregular items, elicited larger repetition effects on both the N250, a component reflecting processing at the level of visual form (orthography), and on the N400, which has been linked to semantic access. In contrast, in the RH/LVF, repetition effects were biased toward irregular items on the N250 and were similar in size across item types for the N400. The results suggest that processing in the LH is more strongly affected by wordform regularity than in the RH, either due to enhanced processing of familiar orthographic patterns or due to the fact that regular forms can be more readily mapped onto phonology. PMID:25278134

  17. Assessing the impact of different satellite retrieval methods on forecast available potential energy

    NASA Technical Reports Server (NTRS)

    Whittaker, Linda M.; Horn, Lyle H.

    1990-01-01

    The effects of the inclusion of satellite temperature retrieval data, and of different satellite retrieval methods, on forecasts made with the NASA Goddard Laboratory for Atmospheres (GLA) fourth-order model were investigated using, as the parameter, the available potential energy (APE) in its isentropic form. Calculation of the APE were used to study the differences in the forecast sets both globally and in the Northern Hemisphere during 72-h forecast period. The analysis data sets used for the forecasts included one containing the NESDIS TIROS-N retrievals, the GLA retrievals using the physical inversion method, and a third, which did not contain satellite data, used as a control; two data sets, with and without satellite data, were used for verification. For all three data sets, the Northern Hemisphere values for the total APE showed an increase throughout the forecast period, mostly due to an increase in the zonal component, in contrast to the verification sets, which showed a steady level of total APE.

  18. Potential large animal models for gene therapy of human genetic diseases of immune and blood cell systems.

    PubMed

    Bauer, Thomas R; Adler, Rima L; Hickstein, Dennis D

    2009-01-01

    Genetic mutations involving the cellular components of the hematopoietic system--red blood cells, white blood cells, and platelets--manifest clinically as anemia, infection, and bleeding. Although gene targeting has recapitulated many of these diseases in mice, these murine homologues are limited as translational models by their small size and brief life span as well as the fact that mutations induced by gene targeting do not always faithfully reflect the clinical manifestations of such mutations in humans. Many of these limitations can be overcome by identifying large animals with genetic diseases of the hematopoietic system corresponding to their human disease counterparts. In this article, we describe human diseases of the cellular components of the hematopoietic system that have counterparts in large animal species, in most cases carrying mutations in the same gene (CD18 in leukocyte adhesion deficiency) or genes in interacting proteins (DNA cross-link repair 1C protein and protein kinase, DNA-activated catalytic polypeptide in radiation-sensitive severe combined immunodeficiency). Furthermore, we describe the potential of these animal models to serve as disease-specific preclinical models for testing the efficacy and safety of clinical interventions such as hematopoietic stem cell transplantation or gene therapy before their use in humans with the corresponding disease. PMID:19293460

  19. Potential Large Animal Models for Gene Therapy of Human Genetic Diseases of Immune and Blood Cell Systems

    PubMed Central

    Bauer, Thomas R.; Adler, Rima L.; Hickstein, Dennis D.

    2009-01-01

    Genetic mutations involving the cellular components of the hematopoietic system—red blood cells, white blood cells, and platelets—manifest clinically as anemia, infection, and bleeding. Although gene targeting has recapitulated many of these diseases in mice, these murine homologues are limited as translational models by their small size and brief life span as well as the fact that mutations induced by gene targeting do not always faithfully reflect the clinical manifestations of such mutations in humans. Many of these limitations can be overcome by identifying large animals with genetic diseases of the hematopoietic system corresponding to their human disease counterparts. In this article, we describe human diseases of the cellular components of the hematopoietic system that have counterparts in large animal species, in most cases carrying mutations in the same gene (CD18 in leukocyte adhesion deficiency) or genes in interacting proteins (DNA cross-link repair 1C protein and protein kinase, DNA-activated, catalytic polypeptide in radiation-sensitive severe combined immunodeficiency). Furthermore, we describe the potential of these animal models to serve as disease-specific, preclinical models for testing the efficacy and safety of clinical interventions such as hematopoietic stem cell transplantation or gene therapy approaches before their use in humans with the corresponding disease. PMID:19293460

  20. Role of the Outer Pore Domain in Transient Receptor Potential Vanilloid 1 Dynamic Permeability to Large Cations*

    PubMed Central

    Munns, Clare H.; Chung, Man-Kyo; Sanchez, Yuly E.; Amzel, L. Mario; Caterina, Michael J.

    2015-01-01

    Transient receptor potential vanilloid 1 (TRPV1) has been shown to alter its ionic selectivity profile in a time- and agonist-dependent manner. One hallmark of this dynamic process is an increased permeability to large cations such as N-methyl-d-glucamine (NMDG). In this study, we mutated residues throughout the TRPV1 pore domain to identify loci that contribute to dynamic large cation permeability. Using resiniferatoxin (RTX) as the agonist, we identified multiple gain-of-function substitutions within the TRPV1 pore turret (N628P and S629A), pore helix (F638A), and selectivity filter (M644A) domains. In all of these mutants, maximum NMDG permeability was substantially greater than that recorded in wild type TRPV1, despite similar or even reduced sodium current density. Two additional mutants, located in the pore turret (G618W) and selectivity filter (M644I), resulted in significantly reduced maximum NMDG permeability. M644A and M644I also showed increased and decreased minimum NMDG permeability, respectively. The phenotypes of this panel of mutants were confirmed by imaging the RTX-evoked uptake of the large cationic fluorescent dye YO-PRO1. Whereas none of the mutations selectively altered capsaicin-induced changes in NMDG permeability, the loss-of-function phenotypes seen with RTX stimulation of G618W and M644I were recapitulated in the capsaicin-evoked YO-PRO1 uptake assay. Curiously, the M644A substitution resulted in a loss, rather than a gain, in capsaicin-evoked YO-PRO1 uptake. Modeling of our mutations onto the recently determined TRPV1 structure revealed several plausible mechanisms for the phenotypes observed. We conclude that side chain interactions at a few specific loci within the TRPV1 pore contribute to the dynamic process of ionic selectivity. PMID:25568328

  1. Potential for large-scale submarine slope failure and tsunami generation along the U.S. mid-Atlantic coast

    NASA Astrophysics Data System (ADS)

    Driscoll, Neal W.; Weissel, Jeffrey K.; Goff, John A.

    2000-05-01

    The outer continental shelf off southern Virginia and North Carolina might be in the initial stages of large-scale slope failure. A system of en echelon cracks, resembling small-offset normal faults, has been discovered along the outer shelf edge. Swath bathymetric data indicate that about 50 m of down-to-the-east (basinward) normal slip has occurred on these features. From a societal perspective, we need to evaluate the degree of tsunami hazard that might be posed by a major submarine landslide, such as the nearby late Pleistocene Albemarle-Currituck slide, if it nucleated on the newly discovered crack system. Toward this goal, a tsunami scenario is constructed for the nearby coastal zone based on the estimated volume and nature of the potential slide. Although a maximum tsunami height of a few to several meters is predicted, the actual extent of flooding would depend on the tidal state at the time of tsunami arrival as well as the details of the hinterland topography. The Virginia North Carolina coastline and lower Chesapeake Bay would be most at risk, being nearby, low lying, and in a direction opposite to potential slide motion.

  2. Potential sex differences in nonmotor symptoms in early drug-naive Parkinson disease

    PubMed Central

    Umbach, David M.; Peddada, Shyamal D.; Xu, Zongli; Tröster, Alexander I.; Huang, Xuemei; Chen, Honglei

    2015-01-01

    Objective: To examine potential sex differences in nonmotor symptoms (NMS) among drug-naive patients with Parkinson disease (PD), and to identify NMS that can best differentiate patients with early PD from controls. Methods: Our cross-sectional analysis included 414 newly diagnosed, untreated patients with PD (269 men and 145 women) and 188 healthy controls (121 men and 67 women) in the Parkinson's Progression Markers Initiative Study. NMS were measured using well-validated instruments covering sleep, olfactory, neurobehavioral, autonomic, and neuropsychological domains. Results: Male and female patients with PD were fairly comparable on motor presentations but differed on several nonmotor features. Male patients with PD had significantly more pronounced deficits in olfaction (p = 0.02) and in certain cognitive measurements (all p < 0.01) than female patients, whereas female cases experienced higher trait anxiety (p = 0.02). Multiple stepwise logistic regression analysis showed that the combination of NMS measures—University of Pennsylvania Smell Identification Test (UPSIT), Montreal Cognitive Assessment (MoCA), Scales for Outcomes in Parkinson's Disease–Autonomic (SCOPA-AUT), and state anxiety from the State-Trait Anxiety Inventory—effectively differentiated patients with PD from controls with an area under the receiver operating characteristic curve (AUC) of 0.913 (95% confidence interval [CI]: 0.89–0.94). UPSIT, MoCA, and SCOPA-AUT were the most predictive NMS measurements in men (AUC = 0.919; 95% CI: 0.89–0.95) as compared to UPSIT, MoCA, and REM Sleep Behavior Disorder Screening Questionnaire in women (AUC = 0.903; 95% CI: 0.86–0.95). Conclusions: Our analysis revealed notable sex differences in several nonmotor features of patients with de novo PD. Furthermore, we found a parsimonious NMS combination that could effectively differentiate de novo cases from healthy controls. PMID:25925983

  3. Estimating the effects of potential climate and land use changes on hydrologic processes of a large agriculture dominated watershed

    NASA Astrophysics Data System (ADS)

    Neupane, Ram P.; Kumar, Sandeep

    2015-10-01

    Land use and climate are two major components that directly influence catchment hydrologic processes, and therefore better understanding of their effects is crucial for future land use planning and water resources management. We applied Soil and Water Assessment Tool (SWAT) to assess the effects of potential land use change and climate variability on hydrologic processes of large agriculture dominated Big Sioux River (BSR) watershed located in North Central region of USA. Future climate change scenarios were simulated using average output of temperature and precipitation data derived from Special Report on Emission Scenarios (SRES) (B1, A1B, and A2) for end-21st century. Land use change was modeled spatially based on historic long-term pattern of agricultural transformation in the basin, and included the expansion of corn (Zea mays L.) cultivation by 2, 5, and 10%. We estimated higher surface runoff in all land use scenarios with maximum increase of 4% while expanding 10% corn cultivation in the basin. Annual stream discharge was estimated higher with maximum increase of 72% in SRES-B1 attributed from higher groundwater contribution of 152% in the same scenario. We assessed increased precipitation during spring season but the summer precipitation decreased substantially in all climate change scenarios. Similar to decreased summer precipitation, discharge of the BSR also decreased potentially affecting agricultural production due to reduced future water availability during crop growing season in the basin. However, combined effects of potential land use change with climate variability enhanced for higher annual discharge of the BSR. Therefore, these estimations can be crucial for implications of future land use planning and water resources management of the basin.

  4. The Climate Potentials and Side-Effects of Large-Scale terrestrial CO2 Removal - Insights from Quantitative Model Assessments

    NASA Astrophysics Data System (ADS)

    Boysen, L.; Heck, V.; Lucht, W.; Gerten, D.

    2015-12-01

    Terrestrial carbon dioxide removal (tCDR) through dedicated biomass plantations is considered as one climate engineering (CE) option if implemented at large-scale. While the risks and costs are supposed to be small, the effectiveness depends strongly on spatial and temporal scales of implementation. Based on simulations with a dynamic global vegetation model (LPJmL) we comprehensively assess the effectiveness, biogeochemical side-effects and tradeoffs from an earth system-analytic perspective. We analyzed systematic land-use scenarios in which all, 25%, or 10% of natural and/or agricultural areas are converted to tCDR plantations including the assumption that biomass plantations are established once the 2°C target is crossed in a business-as-usual climate change trajectory. The resulting tCDR potentials in year 2100 include the net accumulated annual biomass harvests and changes in all land carbon pools. We find that only the most spatially excessive, and thus undesirable, scenario would be capable to restore the 2° target by 2100 under continuing high emissions (with a cooling of 3.02°C). Large-scale biomass plantations covering areas between 1.1 - 4.2 Gha would produce a climate reduction potential of 0.8 - 1.4°C. tCDR plantations at smaller scales do not build up enough biomass over this considered period and the potentials to achieve global warming reductions are substantially lowered to no more than 0.5-0.6°C. Finally, we demonstrate that the (non-economic) costs for the Earth system include negative impacts on the water cycle and on ecosystems, which are already under pressure due to both land use change and climate change. Overall, tCDR may lead to a further transgression of land- and water-related planetary boundaries while not being able to set back the crossing of the planetary boundary for climate change. tCDR could still be considered in the near-future mitigation portfolio if implemented on small scales on wisely chosen areas.

  5. Sediment pollution in the Elbe estuary and its potential toxicity at different trophic levels.

    PubMed

    Wetzel, Markus A; Wahrendorf, Dierk-Steffen; von der Ohe, Peter C

    2013-04-01

    Sediment contamination is one of the most pressing environmental problems in estuaries of industrialized countries and is of special interest to water managers involved in waterway maintenance dredging. In the present study, eight heavy metals (As, Pb, Cd, Cr, Cu, Ni, Hg, and Zn) and 41 organic compounds (pentachlorbenzol (PeCB), hexachlorbenzol (HCB), 7 polychlorinated biphenyls (PCBs), the hexachlorocyclohexanes α-HCH, β-HCH, γ-HCH, 6 dichlorodiphenyltrichloroethane isomers, organochlorine styrene (OCS), octachloronaphthalene (OCN), 15 polycyclic aromatic hydrocarbons (PAHs), and 6 organotin (OT) compounds) were analyzed in surface sediments at 36 sites in the Elbe estuary in 2006. Correlation analysis showed a general decrease in sediment contaminant concentrations from the stations near the port of Hamburg towards the open sea. This decrease was significant (Spearman's rank correlation, p<0.05) with most pollutants. In addition, cluster analysis identified five groups of sites with different sediment contaminant patterns within the Elbe estuary. Worst case toxic risks stemming from sediment-bound organic pollutants were predicted using the Toxic Unit approach, based on estimated pore-water concentrations under equilibrium conditions and acute LC50 values for three standard test organisms of the trophic levels of fish, invertebrates, and algae. The estimated sediment toxicity was significantly higher in the inner part (river-km 630 to 660) compared with the estuarine mouth. Moreover, potential toxicity of organic pollutants estimated for invertebrates and for fish exceeded acute-based effect thresholds at 30 and 24 stations, respectively. Chronic effects for invertebrates are expected at all sites investigated. We conclude that sediment pollution and related potential toxicity in the Elbe estuary may have more influence on the benthos fauna than expected to date. PMID:23428749

  6. Fast and simple determination of perfluorinated compounds and their potential precursors in different packaging materials.

    PubMed

    Zabaleta, I; Bizkarguenaga, E; Bilbao, D; Etxebarria, N; Prieto, A; Zuloaga, O

    2016-05-15

    A simple and fast analytical method for the determination of fourteen perfluorinated compounds (PFCs), including three perfluoroalkylsulfonates (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA) and ten potential precursors, including four polyfluoroalkyl phosphates (PAPs), four fluorotelomer saturated acids (FTCAs) and two fluorotelomer unsaturated acids (FTUCAs) in different packaging materials was developed in the present work. In order to achieve this objective the optimization of an ultrasonic probe-assisted extraction (UPAE) method was carried out before the analysis of the target compounds by liquid-chromatography-triple quadrupole-tandem mass spectrometry (LC-QqQ-MS/MS). 7 mL of 1 % acetic acid in methanol and a 2.5-min single extraction cycle were sufficient for the extraction of all the target analytes. The optimized analytical method was validated in terms of recovery, precision and method detection limits (MDLs). Apparent recovery values after correction with the corresponding labeled standard were in the 69-103 % and 62-98 % range for samples fortified at 25 ng/g and 50 ng/g concentration levels, respectively and MDL values in the 0.6-2.2 ng/g range were obtained. The developed method was applied to the analysis of plastic (milk bottle, muffin cup, pre-cooked food wrapper and cup of coffee) and cardboard materials (microwave popcorn bag, greaseproof paper for French fries, cardboard box for pizza and cinema cardboard box for popcorn). To the best of our knowledge, this is the first method that describes the determination of fourteen PFCs and ten potential precursors in packaging materials. Moreover, 6:2 FTCA, 6:2 FTUCA and 5:3 FTCA analytes were detected for the first time in microwave popcorn bags. PMID:26992531

  7. Denitrification potential of different land-use types in an agricultural watershed, lower Mississippi valley

    USGS Publications Warehouse

    Ullah, S.; Faulkner, S.P.

    2006-01-01

    Expansion of agricultural land and excessive nitrogen (N) fertilizer use in the Mississippi River watershed has resulted in a three-fold increase in the nitrate load of the river since the early 1950s. One way to reduce this nitrate load is to restore wetlands at suitable locations between croplands and receiving waters to remove run-off nitrate through denitrification. This research investigated denitrification potential (DP) of different land uses and its controlling factors in an agricultural watershed in the lower Mississippi valley (LMV) to help identify sites with high DP for reducing run-off nitrate. Soil samples collected from seven land-use types of an agricultural watershed during spring, summer, fall and winter were incubated in the laboratory for DP determination. Low-elevation clay soils in wetlands exhibited 6.3 and 2.5 times greater DP compared to high-elevation silt loam and low-elevation clay soils in croplands, respectively. DP of vegetated-ditches was 1.3 and 4.2 times that of un-vegetated ditches and cultivated soils, respectively. Soil carbon and nitrogen availability, bulk density, and soil moisture significantly affected DP. These factors were significantly influenced in turn by landscape position and land-use type of the watershed. It is evident from these results that low-elevation, fine-textured soils under natural wetlands are the best locations for mediating nitrate loss from agricultural watersheds in the LMV. Landscape position and land-use types can be used as indices for the assessment/modeling of denitrification potential and identification of sites for restoration for nitrate removal in agricultural watersheds. ?? 2006 Elsevier B.V. All rights reserved.

  8. Reconstruction of Oomycete Genome Evolution Identifies Differences in Evolutionary Trajectories Leading to Present-Day Large Gene Families

    PubMed Central

    Seidl, Michael F.; Van den Ackerveken, Guido; Govers, Francine; Snel, Berend

    2012-01-01

    The taxonomic class of oomycetes contains numerous pathogens of plants and animals but is related to nonpathogenic diatoms and brown algae. Oomycetes have flexible genomes comprising large gene families that play roles in pathogenicity. The evolutionary processes that shaped the gene content have not yet been studied by applying systematic tree reconciliation of the phylome of these species. We analyzed evolutionary dynamics of ten Stramenopiles. Gene gains, duplications, and losses were inferred by tree reconciliation of 18,459 gene trees constituting the phylome with a highly supported species phylogeny. We reconstructed a strikingly large last common ancestor of the Stramenopiles that contained ∼10,000 genes. Throughout evolution, the genomes of pathogenic oomycetes have constantly gained and lost genes, though gene gains through duplications outnumber the losses. The branch leading to the plant pathogenic Phytophthora genus was identified as a major transition point characterized by increased frequency of duplication events that has likely driven the speciation within this genus. Large gene families encoding different classes of enzymes associated with pathogenicity such as glycoside hydrolases are formed by complex and distinct patterns of duplications and losses leading to their expansion in extant oomycetes. This study unveils the large-scale evolutionary dynamics that shaped the genomes of pathogenic oomycetes. By the application of phylogenetic based analyses methods, it provides additional insights that shed light on the complex history of oomycete genome evolution and the emergence of large gene families characteristic for this important class of pathogens. PMID:22230142

  9. Potentials and constraints of different types of soil moisture observations for flood simulations in headwater catchments

    NASA Astrophysics Data System (ADS)

    Bronstert, A.; Creutzfeldt, B.; Graeff, T.; Hajnsek, I.; Heistermann, M.; Itzerott, S.; Jagdhuber, T.; Kneis, D.; Lück, E.; Reusser, D.; Zehe, E.

    2012-04-01

    Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall and by the state of the catchment prior to the rainfall, e.g. by the spatial pattern of the soil moisture, groundwater conditions, and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods and in different scales and their potential use for flood simulation. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly thermogravimetric method, Frequency Domain Reflectometry (FDR) sensors, Spatial-Time Domain Reflectometry (STDR) cluster, Ground Penetrating Radar (GPR), airborne polarimetric synthetic aperture radar (polarimetric-SAR) and Advanced Synthetic Aperture Radar (ASAR) based on the satellite Envisat. We present exemplary soil measurement results, with spatial scales ranging from point scale, via hillslope and field scale to the catchment scale. Only the Spatial-TDR cluster was able to record continuous data. The other methods are limited to the date of over flights (airplane and satellite) or measurement campaigns on the ground. At a first glance, using soil moisture data to initiate better flood modelling (including flood forecasts) seems to be a rather straight forward approach. However, this approach bears several problems regarding the operational use of such data and the model parameterisation: 1) A main constraint is that the observation of spatially distributed soil moisture and the subsequent data processing are still far from an operational stage because continuous or quasi-continuous air-borne observation and processing of soil moisture is not available; 2) remote soil moisture sensors observe only a quite shallow soil depths, which are of restricted relevance for flood generation and water

  10. The role of water nitrogen retention in integrated nutrient management: assessment in a large basin using different modelling approaches

    NASA Astrophysics Data System (ADS)

    Grizzetti, Bruna; Passy, Paul; Billen, Gilles; Bouraoui, Fayçal; Garnier, Josette; Lassaletta, Luis

    2015-06-01

    Assessing the removal of nitrogen (temporary and permanent) in large river basins is complex due to the dependency on climate, hydrological and physical characteristics, and ecosystems functioning. Measurements are generally limited in number and do not account for the full integration of all processes contributing to nitrogen retention in the river basin. However, the estimation of nitrogen retention by the ecosystems is crucial to understanding the nitrate water pollution and the N2O emissions to the atmosphere, as well as the lag time between the implementation of agri-environmental measures to reduce nitrogen pollution and the improvement of water quality. Models have often been used to understand the dynamics of the river basin system. The objective of this study was to assess nitrogen retention in a large river basin, the Seine basin (∼65 000 km2, in France), through the application of three models with different levels of complexity developed for different specific purposes: the GREEN, SWAT and RiverStrahler models. The study analyses the different modelling approaches and compares their estimates of water nitrogen retention over an 11-year period. Then reflexions on the role played by nitrogen retention by aquatic ecosystems in integrated nutrient management are presented. The results of this study are relevant for the understanding of nitrogen retention processes at the large river basin scale and for the analysis of mitigation measure scenarios designed to reduce nitrogen impacts on aquatic ecosystems and climate.

  11. Repeatability and Diagnostic Value of Nasal Potential Difference in a Genetically Admixed Population

    PubMed Central

    Sad, Izabela Rocha; Higa, Laurinda Yoko Shinzato; Leal, Teresinha; Martins, Raisa da Silva; de Almeida, Ana Claudia; Ramos, Eloane Goncalves; de Cabello, Giselda Maria Kalil; Peixoto, Maria Virginia Marques

    2016-01-01

    Background The genetic diversity of the Brazilian population results from three ethnic groups admixture: Europeans, Africans and Amerindians, thus increasing the difficulty of performing cystic fibrosis (CF) diagnosis. The nasal potential difference (NPD) evaluates the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) activity. Despite being a useful CF diagnostic test and a biomarker of CFTR-modulator drugs, it is also highly operator dependent. Therefore, it may be difficult to get accurate results and to interpret them. Wilschanski and Sermet scores were proposed to address these issues. This study aimed to evaluate repeatability and diagnostic value of NPD parameters and Wilschanski and Sermet scores in a CF center in Rio de Janeiro. Methods NPD was performed in 78 subjects. Maximal PD, amiloride response, total chloride response, and Wilschanski and Sermet scores were explored as means (confidence interval, CI). One-way ANOVA was used to compare mean differences and Scheffe test was used to pair-wise comparisons. Repeatability was evaluated by scatter and Bland-Altman plots. The Ethics Committee of the CF Center has approved the study protocol. Parents and adult participants signed an informed consent form. Results Forty-eight healthy-volunteers, 19 non-CF and 11 CF patients were enrolled in this study. Significant differences were found when comparing CF patients’ NPD parameters to the other two groups (P = 0.000). Moreover, no significant differences were found when parameters from non-CF patients were compared with those from healthy volunteers (P > 0.05). The means of NPD parameters and diagnostic scores of each group were in concordance with disease/non-disease conditions. The repeatability data - Wilschanski and Sermet and NPD - allow NPD to be performed in this Brazilian CF Center. Conclusions The present study gathered consistent data for Bland-Altman plots. The results of Wilschanski and Sermet

  12. Overexpression of the Large-Conductance, Ca2+-Activated K+ (BK) Channel Shortens Action Potential Duration in HL-1 Cardiomyocytes

    PubMed Central

    Stimers, Joseph R.; Song, Li; Rusch, Nancy J.; Rhee, Sung W.

    2015-01-01

    Long QT syndrome is characterized by a prolongation of the interval between the Q wave and the T wave on the electrocardiogram. This abnormality reflects a prolongation of the ventricular action potential caused by a number of genetic mutations or a variety of drugs. Since effective treatments are unavailable, we explored the possibility of using cardiac expression of the large-conductance, Ca2+-activated K+ (BK) channel to shorten action potential duration (APD). We hypothesized that expression of the pore-forming α subunit of human BK channels (hBKα) in HL-1 cells would shorten action potential duration in this mouse atrial cell line. Expression of hBKα had minimal effects on expression levels of other ion channels with the exception of a small but significant reduction in Kv11.1. Patch-clamped hBKα expressing HL-1 cells exhibited an outward voltage- and Ca2+-sensitive K+ current, which was inhibited by the BK channel blocker iberiotoxin (100 nM). This BK current phenotype was not detected in untransfected HL-1 cells or in HL-1 null cells sham-transfected with an empty vector. Importantly, APD in hBKα-expressing HL-1 cells averaged 14.3 ± 2.8 ms (n = 10), which represented a 53% reduction in APD compared to HL-1 null cells lacking BKα expression. APD in the latter cells averaged 31.0 ± 5.1 ms (n = 13). The shortened APD in hBKα-expressing cells was restored to normal duration by 100 nM iberiotoxin, suggesting that a repolarizing K+ current attributed to BK channels accounted for action potential shortening. These findings provide initial proof-of-concept that the introduction of hBKα channels into a cardiac cell line can shorten APD, and raise the possibility that gene-based interventions to increase hBKα channels in cardiac cells may hold promise as a therapeutic strategy for long QT syndrome. PMID:26091273

  13. Patterns in Benthic Biodiversity Link Lake Trophic Status to Structure and Potential Function of Three Large, Deep Lakes

    PubMed Central

    Hayford, Barbara L.; Caires, Andrea M.; Chandra, Sudeep; Girdner, Scott F.

    2015-01-01

    Relative to their scarcity, large, deep lakes support a large proportion of the world’s freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world’s largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe’s diversity is indicative of differential response of chironomid

  14. Large-Scale, Complex Shaped Coastline Responses to Different Forms of Local Shoreline Stabilization and Climate Change

    NASA Astrophysics Data System (ADS)

    Ells, K.; Murray, A. B.; Slott, J. M.

    2010-12-01

    Nowhere is the importance of research addressing the dynamics of coupled human-landscape processes more pronounced than on the world’s coasts, where human shoreline stabilization alters the natural evolution of the coastline on large spatial and temporal scales. Slott et al. (2010) extended a recently developed large-scale coastline evolution model to include the effects of beach ‘nourishment’ (importing sand into the nearshore system at a long term rate sufficient to counteract shoreline erosion) on a complex-shaped coastline, finding a surprising human signal over large (100s km) distances (Figure 1); even localized shoreline stabilization efforts, when maintained over decadal time scales, can significantly affect the regional pattern of coastline morphological adjustment in response to changing storm behaviors (Slott, et al., 2010). In this work, we examine the effects of shoreline-stabilization method that involve hard structures, such as sea walls and groyne fields. These methods differ significantly from beach nourishment in terms of large-scale impacts; they hold the shoreline location fixed without adding a flux of sediment into the system. Like beach nourishment, these human manipulations have widespread, significant effects on shoreline change rates, even when the manipulations only occur locally. However, the effects on large-scale coastline morphodynamics also exhibit interesting differences when compared to the beach nourishment case. References Slott, Jordan, A. B. Murray, Andrew Ashton, 2010. Large-Scale Responses of Complex-Shaped Coastlines to Local Shoreline Stabilization and Climate Change, Journal of Geophysical Research—Earth Surface. Figure 1. Evolution of a cuspate-cape shoreline in response to ongoing beach nourishment over 200 years, for six different site selections. a. Initial model shoreline, developed in response to a wave climate approximating recent conditions off of the Carolina coast, USA. b. The influence that beach

  15. Variation potential propagation decreases heat-related damage of pea photosystem I by 2 different pathways.

    PubMed

    Surova, Lyubov; Sherstneva, Oksana; Vodeneev, Vladimir; Sukhov, Vladimir

    2016-03-01

    Local burning is known to generate and propagate variation potential (VP) in plants. VP affects different physiological processes, including reducing heat-related damage to photosystem I (PSI). We investigated mechanisms of the process. Photosynthesis parameters were measured with Dual-PAM-100 and GFS-3000. VP was induced by burning the first mature leaf and then waiting 5, 10, 15, or 20 min to initiate heating of the second mature leaf. Photosystems activities in the second leaf were investigated at 15 and 135 min after heating. In the absence of VP induction, when incubation in hot water (5 min) was used for heating the intact second leaf, PSI and PSII activities decreased after incubation at both exposure temperatures (45°C and 50°C). When local burning of the first leaf induced VP propagation into the second leaf, reduced photosynthesis (PSI) was observed. Arrival of VP in the second leaf prior to hot water incubation at 50°C decreased heating-induced suppression of PSI activity when measured 15 and 135 min later. Dependence of PSI activity on the time interval (5, 10, 15, or 20 min) between VP induction and heating of the second leaf was dissimilar at 15 and 135 min. Heat-induced suppression of PSII activity in the second leaf was stimulated after VP induction. In contrast, the effect of VP on PSI and PSII damage was weak when leaf 2 was heated at 45°C. VP-induced decrease of PSI activity suppression at 15 min after heating was correlated with stimulation of PSII activity suppression, but increase of PSI activity at 135 min after heating was not related to PSII activity. Thus, our results suggest the possibility of 2 different pathways of VP-induced decrease of heat-related PSI damage. PMID:26853242

  16. Protein and mRNA characterization in human colorectal carcinoma cell lines with different metastatic potentials.

    PubMed

    Liang, Li; Qu, Lijuan; Ding, Yanqing

    2007-09-01

    Metastasis, the important characteristic of malignant tumors, is closely associated with a series of changes in the expressions of genes and proteins. In this study, we compared mRNA and protein expressions in a pair of human colorectal carcinoma cell lines named SW620 and SW480 with different metastatic potentials by suppression subtractive hybridization and 2-dimensional gel electrophoresis combined with the matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. After suppression subtractive hybridization and differential screening, 24 differentially expressed gene fragments were obtained, including 9 known genes and 15 novel genes. Nine known genes, such as Cytochrome C, Oxidase II and III, Serum amyloid A, Mitotic Control Protein dis3, Eukaryotic Translation Initiation Factor 4A, function in the process of growth and differentiation, transcription, apoptosis, signal transduction. Six novel genes were found to locate in chromosome 5. Northern blot further confirmed the results. For protein analysis, 16 significantly different protein spots were detected using 2-dimensional gel electrophoresis and peptide mass fingerprinting analysis. The results were confirmed by Western blot. The peptide mass fingerprintings of spots were then compared with the NCBI and SWISS PROT database. The differentially expressed proteins included Galectin-1, Annexin A1, Casein kinase 2, Cytochrome c oxidase subunit VIb, S-100D calcium-binding protein, which may be involved in cell differentiation and proliferation, signal transduction, cell adhesion and migration, and tumor evasion of immune responses. An analysis of these genes and proteins reiterated much of our understanding of the metastatic process and also offered some identified targets without previously characterized functions, especially the novel metastasis associated genes, to be further investigated. Moreover, the results of the phenotypic function-related expression mapping analysis at the mRNA and

  17. Potential for leaching of arsenic from excavated rock after different drying treatments.

    PubMed

    Li, Jining; Kosugi, Tomoya; Riya, Shohei; Hashimoto, Yohey; Hou, Hong; Terada, Akihiko; Hosomi, Masaaki

    2016-07-01

    Leaching of arsenic (As) from excavated rock subjected to different drying methods is compared using sequential leaching tests and rapid small-scale column tests combined with a sequential extraction procedure. Although the total As content in the rock was low (8.81 mg kg(-1)), its resulting concentration in the leachate when leached at a liquid-to-solid ratio of 10 L kg(-1) exceeded the environmental standard (10 μg L(-1)). As existed mainly in dissolved forms in the leachates. All of the drying procedures applied in this study increased the leaching of As, with freeze-drying leading to the largest increase. Water extraction of As using the two tests showed different leaching behaviors as a function of the liquid-to-solid ratio, and achieved average extractions of up to 35.7% and 25.8% total As, respectively. Dissolution of As from the mineral surfaces and subsequent re-adsorption controlled the short-term release of As; dissolution of Fe, Al, and dissolved organic carbon played important roles in long-term As leaching. Results of the sequential extraction procedure showed that use of 0.05 M (NH4)2SO4 underestimates the readily soluble As. Long-term water extraction removed almost all of the non-specifically sorbed As and most of the specifically sorbed As. The concept of pollution potential indices, which are easily determined by the sequential leaching test, is proposed in this study and is considered for possible use in assessing efficacy of treatment of excavated rocks. PMID:27058919

  18. Transmembrane electric potential difference in the protein-pigment complex of photosystem 2.

    PubMed

    Mamedov, M D; Kurashov, V N; Petrova, I O; Semenov, A Yu

    2012-09-01

    The protein-pigment complex of photosystem 2 (PS2) localized in the thylakoid membranes of higher plants, algae, and cyanobacteria is the main source of oxygen on Earth. The light-induced functioning of PS2 is directly linked to electron and proton transfer across the membrane, which results in the formation of transmembrane electric potential difference (ΔΨ). The major contribution to ΔΨ of the PS2 reaction center is due to charge separation between the primary chlorophyll donor P(680) and the quinone acceptor Q(A), accompanied by re-reduction of P(680)(+) by the redox-active tyrosine residue Y(Z). The processes associated with the uptake and release of protons on the acceptor and donor sides of the enzyme, respectively, are also coupled with ΔΨ generation. The objective of this work was to describe the mechanisms of ΔΨ generation associated with the S-state transitions of the water-oxidizing complex in intact PS2 complex and in PS2 preparation depleted of Mn(4)Ca cluster in the presence of artificial electron donors. The findings elucidate the mechanisms of electrogenic reactions on the PS2 donor side and may be a basis for development of an effective solar energy conversion system. PMID:23157254

  19. Monitoring the Effects of Acupoint Antioxidant Intervention by Measuring Electrical Potential Difference along the Meridian

    PubMed Central

    Xu, Ming-Ming; Guo, Jing-Ke; Xu, Jin-Sen; Zhang, Chao-Xin; Liu, Shu-Tao; Liao, Ri-Tao; Lin, Chun-Tong; Guo, Jian-Hui; Rao, Ping-Fan

    2015-01-01

    Previous studies suggest that superoxide anions are possibly traveling along acupuncture meridians. The electrical potential difference (EPD) between acupoints may be related to the movement. To test the above hypothesis, we conducted a study investigating the effects of acupoint antioxidant interventions on the meridian EPD. Firstly, ST39 (L) and ST44 (L) were screened out for the EPD detection along the stomach meridian, and ST36 (L) was selected for interventions including acumassage with the control cream, as well as the TAT-SOD cream for 30 minutes, or injection with reduced glutathione sodium. The EPD between ST39 and ST44 was recorded for 80 minutes and measured again 48 h later. While the EPD increased during the acumassage, the acumassage with TAT-SOD cream and the glutathione injection generated waves of EPD increased, indicating the migration or removal from the visceral organ of a greater quantity of superoxide. Remarkably lower EPD readings 48 h later with both antioxidant acupoint interventions than the mere acumassage imply a more complete superoxide flushing out due to the restored superoxide pathway at the acupoint after interventions. The results confirm superoxide transportation along the meridians and demonstrate a possibility of acupoint EPD measurement as a tool to monitor changes in the meridians and acupoints. PMID:25861356

  20. Microscopy and Cathodoluminescence Spectroscopy Characterization of Quartz Exhibiting Different Alkali-Silica Reaction Potential.

    PubMed

    Kuchařová, Aneta; Götze, Jens; Šachlová, Šárka; Pertold, Zdeněk; Přikryl, Richard

    2016-02-01

    Different quartz types from several localities in the Czech Republic and Sweden were examined by polarizing microscopy combined with cathodoluminescence (CL) microscopy, spectroscopy, and petrographic image analysis, and tested by use of an accelerated mortar bar test (following ASTM C1260). The highest alkali-silica reaction potential was indicated by very fine-grained chert, containing significant amounts of fine-grained to cryptocrystalline matrix. The chert exhibited a dark red CL emission band at ~640 nm with a low intensity. Fine-grained orthoquartzites, as well as fine-grained metamorphic vein quartz, separated from phyllite exhibited medium expansion values. The orthoquartzites showed various CL of quartz grains, from blue through violet, red, and brown. Two CL spectral bands at ~450 and ~630 nm, with various intensities, were detected. The quartz from phyllite displayed an inhomogeneous dark red CL with two CL spectral bands of low intensities at ~460 and ~640 nm. The massive coarse-grained pegmatite quartz from pegmatite was assessed to be nonreactive and displayed a typical short-lived blue CL (~480 nm). The higher reactivity of the fine-grained hydrothermal quartz may be connected with high concentrations of defect centers, and probably with amorphized micro-regions in the quartz, respectively; indicated by a yellow CL emission (~570 nm). PMID:26790877

  1. How culture gets embrained: Cultural differences in event-related potentials of social norm violations

    PubMed Central

    Mu, Yan; Kitayama, Shinobu; Han, Shihui; Gelfand, Michele J.

    2015-01-01

    Humans are unique among all species in their ability to develop and enforce social norms, but there is wide variation in the strength of social norms across human societies. Despite this fundamental aspect of human nature, there has been surprisingly little research on how social norm violations are detected at the neurobiological level. Building on the emerging field of cultural neuroscience, we combine noninvasive electroencephalography (EEG) with a new social norm violation paradigm to examine the neural mechanisms underlying the detection of norm violations and how they vary across cultures. EEG recordings from Chinese and US participants (n = 50) showed consistent negative deflection of event-related potential around 400 ms (N400) over the central and parietal regions that served as a culture-general neural marker of detecting norm violations. The N400 at the frontal and temporal regions, however, was only observed among Chinese but not US participants, illustrating culture-specific neural substrates of the detection of norm violations. Further, the frontal N400 predicted a variety of behavioral and attitudinal measurements related to the strength of social norms that have been found at the national and state levels, including higher culture superiority and self-control but lower creativity. There were no cultural differences in the N400 induced by semantic violation, suggesting a unique cultural influence on social norm violation detection. In all, these findings provided the first evidence, to our knowledge, for the neurobiological foundations of social norm violation detection and its variation across cultures. PMID:26621713

  2. An exploratory study of a finite difference method for calculating unsteady transonic potential flow

    NASA Technical Reports Server (NTRS)

    Bennett, R. M.; Bland, S. R.

    1979-01-01

    A method for calculating transonic flow over steady and oscillating airfoils was developed by Isogai. The full potential equation is solved with a semi-implicit, time-marching, finite difference technique. Steady flow solutions are obtained from time asymptotic solutions for a steady airfoil. Corresponding oscillatory solutions are obtained by initiating an oscillation and marching in time for several cycles until a converged periodic solution is achieved. The method is described in general terms and results for the case of an airfoil with an oscillating flap are presented for Mach numbers 0.500 and 0.875. Although satisfactory results are obtained for some reduced frequencies, it is found that the numerical technique generates spurious oscillations in the indicial response functions and in the variation of the aerodynamic coefficients with reduced frequency. These oscillations are examined with a dynamic data reduction method to evaluate their effects and trends with reduced frequency and Mach number. Further development of the numerical method is needed to eliminate these oscillations.

  3. Prebiotic potential of Agave angustifolia Haw fructans with different degrees of polymerization.

    PubMed

    Velázquez-Martínez, José Rodolfo; González-Cervantes, Rina M; Hernández-Gallegos, Minerva Aurora; Mendiola, Roberto Campos; Aparicio, Antonio R Jiménez; Ocampo, Martha L Arenas

    2014-01-01

    Inulin-type fructans are the most studied prebiotic compounds because of their broad range of health benefits. In particular, plants of the Agave genus are rich in fructans. Agave-derived fructans have a branched structure with both β-(2→1) and β-(2→6) linked fructosyl chains attached to the sucrose start unit with a degree of polymerization (DP) of up to 80 fructose units. The objective of this work was to assess the prebiotic potential of three Agave angustifolia Haw fructan fractions (AFF) with different degrees of polymerization. The three fructan fractions were extracted from the agave stem by lixiviation and then purified by ultrafiltration and ion exchange chromatography: AFF1, AFF2 and AFF3 with high (3-60 fructose units), medium (2-40) and low (2-22) DP, respectively. The fructan profile was determined with high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), which confirmed a branched fructan structure. Structural elucidation was performed by Fourier Transform Infra-Red Spectroscopy. The AFF spectrum shows characteristic fructan bands. The prebiotic effect of these fractions was assessed in vitro through fermentation by Bifidobacterium and Lactobacillus strains. Four growth patterns were observed. Some bacteria did not grow with any of the AFF, while other strains grew with only AFF3. Some bacteria grew according to the molecular weight of the AFF and some grew indistinctly with the three fructan fractions. PMID:25153877

  4. Phytochemical screening, antioxidants and antimicrobial potential of Lantana camara in different solvents

    PubMed Central

    Naz, Rabia; Bano, Asghari

    2013-01-01

    Objective To evaluate the antioxidant activity, hydrogen peroxide radicals scavenging activity, reducing power, the total phenolic and flavonoids contents, and antimicrobial and antifungal activities of methanol, ethanol and water extracts of leaves of Lantana camara (L. camara). Methods Methanol, ethanol and water extracts were evaluated against four Gram positive and Gram negative bacterial isolates (Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus subtilis) and two fungal strains (Aspergillus fumigatus and Aspergillus flavus). Methanol extract at different concentrations was tested for antioxidant potential and phytochemicals were determined by using spectrophotometric method. Results The total phenolic content was (40.859±0.017) mg gallic acid/g in the leaves of L. camara, while the total flavonoids was (53.112±0.199) mg/g dry weight. Methanol leaf extract of L. camara showed maximum antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa and was also effective against other bacterial strains as compared to ethanol and aqueous extracts of leaves. The methanol leaf extract of L. camara exhibited significant inhibition (71%) and (66%) against Aspergillus fumigatus and Aspergillus flavus respectively. Conclusions The methanol extract of the L. camara leaves is effective against selected bacterial and fungal strains. Its phytochemical contents have broad antimicrobial properties and the plant might be a novel source of antimicrobial drug.

  5. How culture gets embrained: Cultural differences in event-related potentials of social norm violations.

    PubMed

    Mu, Yan; Kitayama, Shinobu; Han, Shihui; Gelfand, Michele J

    2015-12-15

    Humans are unique among all species in their ability to develop and enforce social norms, but there is wide variation in the strength of social norms across human societies. Despite this fundamental aspect of human nature, there has been surprisingly little research on how social norm violations are detected at the neurobiological level. Building on the emerging field of cultural neuroscience, we combine noninvasive electroencephalography (EEG) with a new social norm violation paradigm to examine the neural mechanisms underlying the detection of norm violations and how they vary across cultures. EEG recordings from Chinese and US participants (n = 50) showed consistent negative deflection of event-related potential around 400 ms (N400) over the central and parietal regions that served as a culture-general neural marker of detecting norm violations. The N400 at the frontal and temporal regions, however, was only observed among Chinese but not US participants, illustrating culture-specific neural substrates of the detection of norm violations. Further, the frontal N400 predicted a variety of behavioral and attitudinal measurements related to the strength of social norms that have been found at the national and state levels, including higher culture superiority and self-control but lower creativity. There were no cultural differences in the N400 induced by semantic violation, suggesting a unique cultural influence on social norm violation detection. In all, these findings provided the first evidence, to our knowledge, for the neurobiological foundations of social norm violation detection and its variation across cultures. PMID:26621713

  6. Shifted excitation Raman difference spectroscopy: a potential tool for outdoor measurements in precision agriculture

    NASA Astrophysics Data System (ADS)

    Maiwald, Martin; Müller, André; Selbeck, Jörn; Käthner, Jana; Zude, Manuela; Fleury, Dominique; Sumpf, Bernd; Erbert, Götz; Tränkle, Günther

    2015-06-01

    In this work we present Shifted Excitation Raman Difference Spectroscopy (SERDS) as a potential spectroscopic tool for outdoor measurements in precision agriculture. A dual-wavelength diode laser at 785 nm is used as an excitation light source which provides an optical power up to 100 mW in cw-operation. Both emission lines for SERDS show single mode operation with a spectral width of <= 11 pm and a spectral distance of about 10 cm-1 over the whole power range. Raman experiments on apples are carried out and show Raman signals from wax layer and β-carotene. Raman investigations under daylight conditions are performed to simulate outdoor measurements. Here, polystyrene (PS) is used as test sample. A broadband signal together with narrow absorption lines of water vapor and Fraunhofer lines of singly ionized calcium (Ca II) mask the Raman lines of PS. Only the strong Raman signal at 999 cm-1 is visible. SERDS efficiently separates the Raman signals of PS from the background signals and a 14-fold improvement of the signal-tobackground noise ratio is achieved.

  7. Potential effects of climate change on the water level, flora and macro-fauna of a large neotropical wetland.

    PubMed

    Úbeda, Bárbara; Di Giacomo, Adrian S; Neiff, Juan José; Loiselle, Steven A; Poi, Alicia S Guadalupe; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

    2013-01-01

    Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

  8. Potential Effects of Climate Change on the Water Level, Flora and Macro-fauna of a Large Neotropical Wetland

    PubMed Central

    Úbeda, Bárbara; Di Giacomo, Adrian S.; Neiff, Juan José; Loiselle, Steven A.; Guadalupe Poi, Alicia S.; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

    2013-01-01

    Possible consequences of climate change in one of the world’s largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

  9. Electromagnetic phase differences in the coherent backscattering enhancement mechanism for random media consisting of large nontransparent spheres.

    PubMed

    Stankevich, Dmitriy; Istomina, Larissa; Shkuratov, Yuriy; Videen, Gorden

    2007-03-20

    Phase curves of intensity are calculated for light scattering in media randomly packed with large nontransparent spheres (x=125), the surfaces of which reflect according to the Fresnel equations. We consider three values of refractive index: m = 0.73 + i5.93 (metal Al), 1.6 + i1.72 (metal Fe), and 1.5 + i0.1 (black glass). We use a Monte Carlo ray-tracing approach. Different kinds of electromagnetic phase differences of reciprocal trajectories are investigated for the second and third orders of scattering; the highest orders give comparatively small contributions due to the backward-scattering indicatrix of large nontransparent spheres. We find that the main electromagnetic phase difference between the direct and time-reversal (reciprocal) trajectories is the outer phase difference that depends only on the relative positions of the first and last points of the ray reflections and the phase angle. The inner phase difference is connected with the changing path length of the ray inside the medium. This depends on the particle size and the phase angle that is the angle between the source and receiver from the scatterer, i.e., 180 degrees minus the scattering angle. The inner phase difference can give oscillations in the phase curve consisting of second-order components if the medium consists of strictly monodisperse spheres. Usually the coherent backscattering enhancement is calculated ignoring the shadow-hiding effect. We show that accounting for the shadowing of the reciprocal trajectory is important for the formation of the backscattering effect. The third-order scattering surge is a superposition of wide and narrow opposition spikes that correspond to two different types of scattering trajectories, closed and opened ones. The first type is due to scattering by two particles; the second one corresponds to scattering by three particles. PMID:17334449

  10. Stellar metallicities beyond the Local Group: the potential of J-band spectroscopy with extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Evans, C. J.; Davies, B.; Kudritzki, R.-P.; Puech, M.; Yang, Y.; Cuby, J.-G.; Figer, D. F.; Lehnert, M. D.; Morris, S. L.; Rousset, G.

    2011-03-01

    We present simulated J-band spectroscopy of red giants and supergiants with a 42 m European Extremely Large Telescope (E-ELT), using tools developed toward the EAGLE Phase A instrument study. The simulated spectra are used to demonstrate the validity of the 1.15-1.22 μm region to recover accurate stellar metallicities from Solar and metal-poor (one tenth Solar) spectral templates. From tests at spectral resolving powers of four and ten thousand, we require continuum signal-to-noise ratios in excess of 50 (per two-pixel resolution element) to recover the input metallicity to within 0.1 dex. We highlight the potential of direct estimates of stellar metallicites (over the range - 1 < [Fe/H] < 0) of red giants with the E-ELT, reaching out to distances of ~ 5 Mpc for stars near the tip of the red giant branch. The same simulations are also used to illustrate the potential for quantitative spectroscopy of red supergiants beyond the Local Volume to tens of Mpc. Calcium triplet observations in the I-band are also simulated to provide a comparison with contemporary techniques. Assuming the EAGLE instrument parameters and simulated performances from adaptive optics, the J-band method is more sensitive in terms of recovering metallicity estimates for a given target. This appears very promising for ELT studies of red giants and supergiants, offering a direct metallicity tracer at a wavelength which is less affected by extinction than shortward diagnostics and, via adaptive optics, with better image quality.

  11. Quantity, composition and water contamination potential of ash produced under different wildfire severities.

    PubMed

    Santín, Cristina; Doerr, Stefan H; Otero, Xosé L; Chafer, Chris J

    2015-10-01

    Wildfires frequently threaten water quality through the transfer of eroded ash and soil into rivers and reservoirs. The ability to anticipate risks for water resources from wildfires is fundamental for implementing effective fire preparedness plans and post-fire mitigation measures. Here we present a new approach that allows quantifying the amount and characteristics of ash generated under different wildfire severities and its respective water contamination potential. This approach is applied to a wildfire in an Australian dry sclerophyll eucalypt forest, but can be adapted for use in other environments. The Balmoral fire of October 2013 affected 12,694 ha of Sydney's forested water supply catchment. It produced substantial ash loads that increased with fire severity, with 6, 16 and 34 Mg ha(-1) found in areas affected by low, high and extreme fire severity, respectively. Ash bulk density was also positively related to fire severity. The increase with fire severity in the total load and bulk density of the ash generated is mainly attributed to a combination of associated increases in (i) total amount of fuel affected by fire and (ii) contribution of charred mineral soil to the ash layer. Total concentrations of pollutants and nutrients in ash were mostly unrelated to fire severity and relatively low compared to values reported for wildfire ash in other environments (e.g. 4.0-7.3mg As kg(-1); 2.3-4.1 B mg kg(-1); 136-154 P mg kg(-1)). Solubility of the elements analysed was also low, less than 10% of the total concentration for all elements except for B (6-14%) and Na (30-50%). This could be related to a partial loss of soluble components by leaching and/or wind erosion before the ash sampling (10 weeks after the fire and before major ash mobilisation by water erosion). Even with their relatively low concentrations of potential pollutants, the substantial total ash loads found here represent a water contamination risk if transported into the hydrological network

  12. Spatial and temporal variations in rainfall over Darwin and its vicinity during different large-scale environments

    NASA Astrophysics Data System (ADS)

    Rauniyar, Surendra P.; Walsh, Kevin J. E.

    2016-02-01

    This study analyses the regional variations in rainfall over Darwin and its vicinity due to different large-scale circulations during the Australian summer by utilizing the combination of in situ and C-band polarimetric radar rainfall data at hourly resolution. The eight phases of the Madden-Julian oscillation as defined by Wheeler and Hendon (Mon Weather Rev 132(8):1917-1932, 2004) were used as indicators of different large-scale environments. The analysis found that the large-scale forcing starts to build up from phase 4 by the reversal of low- to mid-level easterly winds to moist westerly winds, reaching a maximum in phase 5 and weakening through phases 6-7. During phases 4-6, most of the study domain experiences widespread rainfall, but with distinct spatial and temporal structures. In addition, during these phases, coastal areas near Darwin receive more rainfall in the early morning (0200-0400 LT) due to the spreading or expansion of rainfall from the Beagle Gulf, explaining the occurrence of a secondary diurnal rainfall peak over Darwin. In contrast, local-scale mechanisms (sea breezes) reinvigorate from phase 8, further strengthening through phases 1-3, when low-level easterly winds become established over Darwin producing rainfall predominately over land and island locations during the afternoon. During these phases, below average rainfall is observed over most of the radar domain, except over the Tiwi Islands in phase 2.

  13. Quaternary megafans, large rivers and other avulsive systems: a potential "who is who" in the geological record

    NASA Astrophysics Data System (ADS)

    Latrubesse, E. M.

    2012-12-01

    A fascinating discussion has been recently calling the attention of sedimentologists and geomorphologists regarding to the dominant fluvial styles preserved in the geological record. While some authors postulate that distributary (or distributive) patterns are the most important systems likely to dominate the alluvial rock record (Weissmann et al.2010, among others) others suggest that a variety of fluvial styles are remarkably preserved in the geological record, rejecting the importance of the distributary systems (such as megafans and other like fans coastal systems) (Fielding et al, 2012 among others). However, the Quaternary record of the largest depositional tracks on Earth has been not assessed in a comparative and detailed way. Here I present results from some of the most important Quaternary areas of sedimentation of the world such as the alluvial belts of the largest rivers, the largest megafans and other impressive fluvial dominated wetlands in active tectonic basins. My study is based on field work I carried out in many of the analyzed areas, a literature review and remote sensing products. Specific examples are discussed from several rivers of the Amazon basin, the Parana River, the Mississippi River, among others. Large depositional tracks in forelands, platforms and intracratonic basins such as the Chaco, the Orinoco Llanos, the Bananal and Pantanal basin, the Ucamara depression, and the Indo-Gangetic plain, which contain a variety of complex avulsive systems and megafans, are discussed. A main conclusion is that megafans and similar distributary systems, avulsive systems with a variety of channel patterns and linear fluvial belts of major rivers, have the potential for preservation in the geological record. The scarcity of purely braided systems in large rivers is noticeable and they are mainly constrained to small-medium size channels, short length piedmont courses or related to relatively small alluvial fans. Meandering and anabranching systems are

  14. PDMS microwells for multi-parametric monitoring of single mitochondria on a large scale: a study of their individual membrane potential and endogenous NADH.

    PubMed

    Vajrala, Venkata Suresh; Suraniti, Emmanuel; Rigoulet, Michel; Devin, Anne; Sojic, Neso; Arbault, Stéphane

    2016-08-01

    Microwell arrays have been developed to monitor simultaneously, and on a large scale, multiple metabolic responses of single mitochondria. Wells of 50 to 1000 μm-diameter were prepared based on easy structuration of thin polydimethylsiloxane layers (PDMS; 100 μm thickness). Their surface treatment with oxygen plasma allowed the immobilization in situ and observation with time of populations of single isolated mitochondria. Their metabolic activities could be monitored individually by fluorescence microscopy under several activation/inhibition conditions. We measured the concomitant variations of two main metabolic parameters - the endogenous NADH level and the internal membrane potential difference Δψ owing to a cationic fluorescent probe (TMRM) - at energized, uncoupled and inhibited stages of the mitochondrial respiratory chain. Microwell arrays allowed analyses on large populations, and consequently statistical studies with a single organelle resolution. Thus, we observed rapid individual polarizations and depolarizations of mitochondria following their supply with the energetic substrate, while an averaged global polarization (increase of TMRM fluorescence within mitochondria) and NADH increase were detected for the whole population. In addition, statistical correlation studies show that the NADH content of all mitochondria tends toward a metabolic limit and that their polarization-depolarization ability is ubiquitous. These results demonstrate that PDMS microwell platforms provide an innovative approach to better characterize the individual metabolic status of isolated mitochondria, possibly as a function of their cell or organ origin or in different physio-pathological situations. PMID:27384613

  15. Contribution of large submarine landslide to tsunami potential in the NE Atlantic region: The Gorringe Bank case study

    NASA Astrophysics Data System (ADS)

    Ramalho, Inês; Omira, Rachid; Baptista, Maria Ana; Miranda, Miguel; Terrinha, Pedro; Batista, Luis; Roque, Cristina

    2015-04-01

    Tsunami is recognized as a natural hazard, and it is now widely accepted that submarine mass-failures are one of possible tsunami sources. Various studies on tsunami-induced by submarine landslides were carried out based on a spontaneous trigger of the mass-failure. In this study we focus on the deep-water submarine landslide in the Gorringe Bank (GB) area, NE Atlantic. In particular, we investigate the contribution of such mass-failure, as an additional source, to tsunami potential. We assume that an initial tsunami is generated by a large earthquake in the south west Iberia margin area that also initiates the failure of the GB landslide. This mass-failure can play the role of a secondary source of tsunami and contribute to tsunami potential. We simulate the tsunami generation as combination between the sea free surface perturbation caused instantaneously by the earthquake and the initial wave generated progressively due to the slide motion. Okada's equations are employed to compute the initial tsunami induced by the earthquake. While, a multi-layers viscous shallow water (VSW) model is used to simulate the flow of the submarine mass failure and the resulting tsunami wave. To model the propagation and coastal impact of the tsunami resulted from a combination of earthquake and landslide, we use a non-linear shallow water model and a nested grid system that allow estimating properly near-shore wave heights and inundation. We consider a 1755-like earthquake of magnitude Mw8.5, and a landslide of an approximate volume of about 60 km3. The characteristics of the landslide come from the analysis of detailed marine geological data including the erosional area (dimensions and scarps) and the seismic profiles. The results are presents in terms of: i) evidences of submarine mass failures in the area of GB; ii) simulations of the slide motion and the resulting tsunami wave; iii) simulations of the tsunami generated by a combination of two triggers: earthquake and landslide

  16. Unusually large coupling constants in diradicals obtained from excitation of mixed radical centers: a theoretical study on potential photomagnets.

    PubMed

    Bhattacharjee, Ujjal; Panda, Anirban; Latif, Iqbal A; Datta, Sambhu N

    2010-06-24

    Three sets of heterosubstituted, interconvertible, cyclophanediene (CPD), and dihydropyrenes (DDPs) and one such set involving dinitrilepyrenes were examined by UB3LYP broken-symmetry methodology with 6-311++g(d,p) bases. Nitronyl nitroxide and oxoverdazyl (with both N and C terminals) are monoradical centers, whereas CPD and DDP moieties serve as couplers. The photoexcited CPD converts to DDP. The calculated exchange coupling constant (J) for o-VER(N)-DDP-NN is surprisingly high, 6412 cm(-1), and much larger than 28.9 cm(-1) for the CPD species, but the unsubstituted DDP is known to transform readily into pyrene, with the loss of reversibility. Nevertheless, o-VER(N)-(15,16-dinitrile)DDP-NN also has a large J value, 589.4 cm(-1). The corresponding CPD species has J = 53.3 cm(-1). We predict that the latter CPD and DDP diradicals are potential molecules to synthesize photomagnetic materials. The o-VER(N)-DDP-NN can also be an excellent photomagnetic switch at a considerably low temperature. PMID:20509622

  17. An investigation into the role that a transverse magnetic field plays in the formation of large anode sheath potentials

    NASA Astrophysics Data System (ADS)

    Foster, J. E.; Gallimore, A. D.

    1996-11-01

    A 9.25 A low-pressure (45-55 mTorr) hollow cathode arc discharge has been used to simulate plasma processes that occur at the anode of magnetoplasmadynamic accelerators used for space propulsion applications. The interest in the near-anode region is related to findings of past research, which indicate that large anode sheath potentials can drive as much as 70% of the input electrical power into the anode, thus degrading thrust efficiency. Presented here are results that essentially characterize the behavior of the near-anode plasma as a function of a transverse magnetic field. Plasma diagnostics included single Langmuir probe techniques, emission spectroscopy, and water calorimetry for anode heat flux measurements. Phenomenological arguments based on measurements taken suggest that observed changes in anode fall voltage are related to variations in the measured local electron number density as the magnetic field is varied. This behavior is attributed to the variations in the measured ionization rate, which is shown to be a nonlinear function of transverse magnetic field.

  18. Potential environmental impact of tidal energy extraction in the Pentland Firth at large spatial scales: results of a biogeochemical model

    NASA Astrophysics Data System (ADS)

    van der Molen, Johan; Ruardij, Piet; Greenwood, Naomi

    2016-05-01

    A model study was carried out of the potential large-scale (> 100 km) effects of marine renewable tidal energy generation in the Pentland Firth, using the 3-D hydrodynamics-biogeochemistry model GETM-ERSEM-BFM. A realistic 800 MW scenario and a high-impact scenario with massive expansion of tidal energy extraction to 8 GW scenario were considered. The realistic 800 MW scenario suggested minor effects on the tides, and undetectable effects on the biogeochemistry. The massive-expansion 8 GW scenario suggested effects would be observed over hundreds of kilometres away with changes of up to 10 % in tidal and ecosystem variables, in particular in a broad area in the vicinity of the Wash. There, waters became less turbid, and primary production increased with associated increases in faunal ecosystem variables. Moreover, a one-off increase in carbon storage in the sea bed was detected. Although these first results suggest positive environmental effects, further investigation is recommended of (i) the residual circulation in the vicinity of the Pentland Firth and effects on larval dispersal using a higher-resolution model and (ii) ecosystem effects with (future) state-of-the-art models if energy extraction substantially beyond 1 GW is planned.

  19. Potential environmental impact of tidal energy extraction in the Pentland Firth at large spatial scales: results of a biogeochemical model

    NASA Astrophysics Data System (ADS)

    van der Molen, J.; Ruardij, P.; Greenwood, N.

    2015-12-01

    A model study was carried out of the potential large-scale (> 100 km) effects of marine renewable tidal energy generation in the Pentland Firth, using the 3-D hydrodynamics-biogeochemistry model GETM-ERSEM-BFM. A realistic 800 MW scenario and an exaggerated academic 8 GW scenario were considered. The realistic 800 MW scenario suggested minor effects on the tides, and undetectable effects on the biogeochemistry. The academic 8 GW scenario suggested effects would be observed over hundreds of kilometres away with changes of up to 10 % in tidal and ecosystem variables, in particular in a broad area in the vicinity of The Wash. There, waters became less turbid, and primary production increased with associated increases in faunal ecosystem variables. Moreover, a one-off increase in carbon storage in the sea bed was detected. Although these first results suggest positive environmental effects, further investigation is recommended of: (i) the residual circulation in the vicinity of the Pentland Firth and effects on larval dispersal using a higher resolution model, (ii) ecosystem effects with (future) state-of-the-art models if energy extraction substantially beyond 1 GW is planned.

  20. Potential effects of large-scale offshore tidal energy extraction in the Pentland Firth on North Sea biogeochemistry

    NASA Astrophysics Data System (ADS)

    van der Molen, Johan; Ruardij, Piet; Greenwood, Naomi

    2016-04-01

    Final results are presented of a model study to assess the potential wider area effects of large-scale tidal energy extraction in the Pentland Firth on the biogeochemistry. The coupled hydrodynamics-biogeochemistry model GETM-ERSEM-BFM was used in a shelf-wide application with a parameterisation of the effects of power extraction by tidal turbines on fluid momentum. Three secenario runs were carried out: a reference run without turbines, an 800 MW extraction run corresponding to current licenses, and an academic 8 GW extraction run. The changes simulated with the 800 MW extraction were negligible. The academic 8 GW extraction resulted in reductions in tidal elevations along the east coast of the UK that would be measurable (several cm.), and associated reductions in bed-shear stresses. These resulted in reductions in SPM concentrations, increased primary production, and increased biomass of zooplankton and benthic fauna. The effects were most pronounced in the shallow seas surrounding The Wash, with changes of up to 10%. These results indicate that, should tidal power generation substantially beyond the currently licensed amount be planned, either concentrated in one location or spread over multiple locations along the coast, further investigations are advisable.

  1. Large submarine earthquakes that occurred worldwide in a 1-year period (June 2013 to June 2014) - a contribution to the understanding of tsunamigenic potential

    NASA Astrophysics Data System (ADS)

    Omira, R.; Vales, D.; Marreiros, C.; Carrilho, F.

    2015-10-01

    This paper is a contribution to a better understanding of the tsunamigenic potential of large submarine earthquakes. Here, we analyze the tsunamigenic potential of large earthquakes which have occurred worldwide with magnitudes around Mw = 7.0 and greater during a period of 1 year, from June 2013 to June 2014. The analysis involves earthquake model evaluation, tsunami numerical modeling, and sensors' records analysis in order to confirm the generation of a tsunami (or lack thereof) following the occurrence of an earthquake. We also investigate and discuss the sensitivity of tsunami generation to the earthquake parameters recognized to control tsunami occurrence, including the earthquake location, magnitude, focal mechanism and fault rupture depth. Through this analysis, we attempt to understand why some earthquakes trigger tsunamis and others do not, and how the earthquake source parameters are related to the potential of tsunami generation. We further discuss the performance of tsunami warning systems in detecting tsunamis and disseminating the alerts. A total of 23 events, with magnitudes ranging from Mw = 6.7 to Mw = 8.1, have been analyzed. This study shows that about 39 % of the analyzed earthquakes caused tsunamis that were recorded by different sensors with wave amplitudes varying from a few centimeters to about 2 m. Tsunami numerical modeling shows good agreement between simulated waveforms and recorded waveforms, for some events. On the other hand, simulations of tsunami generation predict that some of the events, considered as non-tsunamigenic, caused small tsunamis. We find that most generated tsunamis were caused by shallow earthquakes (depth < 30 km) and thrust faults that took place on/near the subduction zones. The results of this study can help the development of modified and improved versions of tsunami decision matrixes for various oceanic domains.

  2. Systematic review and meta-analysis of nasal potential difference in hypoxia-induced lung injury

    PubMed Central

    Su, Zhenlei; Zhu, Lili; Wu, Jing; Zhao, Runzhen; Ji, Hong-Long

    2016-01-01

    Nasal potential difference (NPD), a well-established in vivo clinical test for cystic fibrosis, reflects transepithelial cation and anion transport in the respiratory epithelium. To analyze whether NPD can be applied to diagnose hypoxic lung injury, we searched PubMed, EMBASE, Scopus, Web of Science, Ovid MEDLINE, and Google Scholar, and analyzed data retrieved from eleven unbiased studies for high altitude pulmonary edema (HAPE) and respiratory distress syndrome (RDS) using the software RevMan and R. There was a significant reduction in overall basal (WMD −5.27 mV, 95% CI: −6.03 to −4.52, P < 0.00001, I2 = 42%), amiloride-sensitive (ENaC) (−2.87 mV, 95% CI: −4.02 to −1.72, P < 0.00001, I2 = 51%), and -resistant fractions (−3.91 mV, 95% CI: −7.64 to −0.18, P = 0.04, I2 = 95%) in lung injury patients. Further analysis of HAPE and RDS separately corroborated these observations. Moreover, SpO2 correlated with ENaC-associated NPD positively in patients only, but apparently related to CFTR-contributed NPD level inversely. These correlations were confirmed by the opposite associations between NPD values and altitude, which had a negative regression with SpO2 level. Basal NPD was significantly associated with amiloride-resistant but not ENaC fraction. Our analyses demonstrate that acute lung injury associated with systemic hypoxia is characterized by dysfunctional NPD. PMID:27488696

  3. Simultaneous measurement and recording of gastric potential difference and intragastric pH in man.

    PubMed

    Scarpignato, C; Galmiche, J P

    1990-01-01

    Gastric potential difference (GPD) is used increasingly as an index of mucosal integrity. The technique for GPD measurement currently employed is however laborious due to the preparation and check of KCl-agarose bridges prior to each experiment. In addition, calculations - usually handmade - are time-consuming and inaccurate. Therefore, a new apparatus allowing continuous recording of basal and drug-induced changes in GPD values was developed. A commercially available 24-hour pH monitor (Proxima Light, Synectics Medical) was modified in order to allow GPD measurement and recording with subsequent elaboration of data. Furthermore, simultaneous measurement of GPD and intragastric pH through the use of a single stomach probe was made possible. The new method was checked towards the classical PD measuring system employing KCl-agarose bridges. The readings obtained with both systems, either in basal conditions or after aspirin, correlated in a highly significant way. Readings proved to be quite stable with a variation, for 150 consecutive values, of less than 2 mV. With this system the effect of pH modifications, obtained through H2 receptor stimulation and inhibition, on the behaviour of GPD values was investigated in healthy volunteers. Analysis of paired data obtained from these experiments showed an inverse relationship between these two parameters. This suggests that GPD and pH should be measured together, especially during experiments aiming to study drug effects on gastric mucosa. Although the apparatus described was developed for PD measurement and recording in the stomach, it can be used easily for PD measurement across the mucosa of the entire digestive tract, for example in the esophagus, colon or rectum. PMID:2225521

  4. Systematic review and meta-analysis of nasal potential difference in hypoxia-induced lung injury.

    PubMed

    Su, Zhenlei; Zhu, Lili; Wu, Jing; Zhao, Runzhen; Ji, Hong-Long

    2016-01-01

    Nasal potential difference (NPD), a well-established in vivo clinical test for cystic fibrosis, reflects transepithelial cation and anion transport in the respiratory epithelium. To analyze whether NPD can be applied to diagnose hypoxic lung injury, we searched PubMed, EMBASE, Scopus, Web of Science, Ovid MEDLINE, and Google Scholar, and analyzed data retrieved from eleven unbiased studies for high altitude pulmonary edema (HAPE) and respiratory distress syndrome (RDS) using the software RevMan and R. There was a significant reduction in overall basal (WMD -5.27 mV, 95% CI: -6.03 to -4.52, P < 0.00001, I(2) = 42%), amiloride-sensitive (ENaC) (-2.87 mV, 95% CI: -4.02 to -1.72, P < 0.00001, I(2) = 51%), and -resistant fractions (-3.91 mV, 95% CI: -7.64 to -0.18, P = 0.04, I(2) = 95%) in lung injury patients. Further analysis of HAPE and RDS separately corroborated these observations. Moreover, SpO2 correlated with ENaC-associated NPD positively in patients only, but apparently related to CFTR-contributed NPD level inversely. These correlations were confirmed by the opposite associations between NPD values and altitude, which had a negative regression with SpO2 level. Basal NPD was significantly associated with amiloride-resistant but not ENaC fraction. Our analyses demonstrate that acute lung injury associated with systemic hypoxia is characterized by dysfunctional NPD. PMID:27488696

  5. Observations of Coastal IO Emissions on the Southern Hemisphere and Emission Potential of Different Seaweed Species

    NASA Astrophysics Data System (ADS)

    Horbanski, Martin; Schmitt, Stefan; Frieß, Udo; Pöhler, Denis; Johnston, Paul; Kreher, Karin; Robinson, Andrew D.; Thomas, Alan; Harris, Neil R. P.; Platt, Ulrich

    2014-05-01

    At coastal sites reactive iodine species emitted by seaweed in the intertidal zone during low tide are known to have an important influence on the atmospheric chemistry. However, many underlying mechanisms are presently not understood. Also coastal studies were focused on a few locations on the northern hemisphere and their predominant seaweed species laminaria digitata and ascophyllum nodosum. Therefore the spatial emission and extent of the areas where halogen chemistry is of importance needs to be much better quantified. Especially in the mid latitudes of the southern hemisphere RHS measurements are very sparse. Here we report the first observations of coastal iodine monoxide (IO) in the southern hemisphere during the HALMA/MAORI campaign which was carried out in February to March 2013 on the east coast of New Zealand's South Island at Shag Point located north of Dunedin. To detect IO we used a mobile Open Light Path Cavity Enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) instrument and a stationary Long Path (LP)-DOAS Instrument, which was furthermore used to measure BrO, O3 and I2. The measurement path was positioned over the water and mainly measured air masses that only passes over submerged seaweed forests. With the CE-DOAS placed close to exposed seaweed patches (mainly Macrocystis Pyrifera) we were able to observe high IO mixing ratios of up to 50 ppt (2ppt detection limit). However, the LP-DOAS did not detect IO above the detection limit of 0.7 ppt. This is consistent with previous observations which found that seaweed only emits halogens when exposed to air. To further investigate the emission potential of the seaweed species we setup a Teflon chamber around the CE-DOAS and measured the emissions of five different species for several hours. Additionally the air in the chamber was probed by a compact gas chromatograph (μDIRAC) for measurements of halocarbons and a TEI Ozone monitor. We found very high IO mixing ratios of up to 500 ppt for

  6. Analysis and Assessment of Tidal Flood Potential at Different Locations in the East Coast of India

    NASA Astrophysics Data System (ADS)

    Bhagawati, Chirantan; Shaileshbhai Patel, Ramkrushnbhai; Pandey, Suchita; Chakraborty, Arun; Jayanarayanan, Kuttippurath

    2016-04-01

    Sea water inundation has always remained a major problem for human civilization in coastal regions. Increase in the frequency of severe to very severe cyclones in Bay of Bengal has made the Eastern Coast of India highly vulnerable for sea water inundation. Tidal effect has a significant contribution to coastal inundation. Wood (1976) proposed a Combined Astronomical Meteorological Index (CAMI) to quantify the risk of tidal flooding due to astronomical tides as well as meteorological parameters. This study deals with the analysis of major tidal components and the changes in sea level as observed from the tidal gauge records of Visakhapatnam, Chennai and Ennore situated in the East Coast of India. The study envisages to analyse (1) tidal characteristics observed at different stations by using Harmonic analysis, (2) to synthesise the missing tidal information using Artificial Neural Network (ANN) and wavelet analyses, (3) to quantify the diurnal as well as seasonal trends in sea level, and (4) to assess the tidal flooding potential at the sites by using the CAMI under different meteorological conditions. The harmonic analysis of Visakhapatnam, Chennai and Ennore shows that Principal Lunar Semidiurnal (M2) is dominant tidal constituent in all three stations. The Form Number (FN) obtained for Visakhapatnam (17.69N 83.27E), Chennai (13.08N 80.29E) and Ennore (13.25N 80.33E) are 0.14, 0.29 and 0.33 respectively. FN of these stations indicates semidiurnal nature of tide in Visakhapatnam and mixed tide in Chennai and Ennore. The monthly fluctuations of sea level in Visakhapatnam from January to July 2014 show that the sea level tends to decrease at a rate of 0.2 m from January to March and then it starts to rise upto May with a similar rate. The network prediction finds high correlation (R=0.9684) between the observed and the target values of ANN. Finally, we also assess the coastal vulnaberility by tidal flooding at the time of perigean spring tide based on the sea level

  7. Comparing the rehydration potential of different milk-based drinks to a carbohydrate-electrolyte beverage.

    PubMed

    Desbrow, Ben; Jansen, Sarah; Barrett, Abby; Leveritt, Michael D; Irwin, Christopher

    2014-12-01

    The aim of this study was to compare the rehydration potential of a carbohydrate-electrolyte beverage with several varieties of milk following exercise-induced fluid losses. Fifteen male participants (age 24.9 ± 5.5 years, height 179.3 ± 4.9 cm, body mass 75.8 ± 6.6 kg (mean ± SD)) lost 2.0% ± 0.2% body mass through intermittent cycling before consuming a different beverage on 4 separate occasions. Drinks included cow's milk (286 kJ·100 mL(-1)), soy milk (273 kJ·100 mL(-1)), a milk-based liquid meal supplement (Sustagen Sport (Nestle); 417 kJ·100 mL(-1)), and a sports drink (Powerade (Coca Cola Ltd); 129 kJ·100 mL(-1)). Beverages were consumed over 1 h in volumes equivalent to 150% of body mass loss. Body mass, blood and urine samples, and measures of gastrointestinal tolerance were obtained before and hourly for 4 h after beverage consumption. Net body mass at the conclusion of each trial was significantly less with Powerade (-1.37 ± 0.3 kg) than with cow's milk (-0.92 ± 0.48 kg), soy milk (-0.78 ± 0.37 kg), and Sustagen Sport (-0.48 ± 0.39 kg). Net body mass was also significantly greater for Sustagen Sport compared with cow's milk trials, but not soy milk. Upon completion of trials, the percentage of beverage retained was Sustagen Sport 65.1% ± 14.7%, soy milk 46.9% ± 19.9%, cow's milk 40.0% ± 24.9%, and Powerade 16.6% ± 16.5%. Changes in plasma volume and electrolytes were unaffected by drink treatment. Subjective ratings of bloating and fullness were higher during all milk trials compared with Powerade whereas ratings of overall thirst were not different between beverages. Milk-based drinks are more effective rehydration options compared with traditional sports drinks. The additional energy, protein, and sodium in a milk-based liquid meal supplement facilitate superior fluid recovery following exercise. PMID:25315686

  8. On the differences in element abundances of energetic ions from corotating events and from large solar events

    NASA Technical Reports Server (NTRS)

    Reames, D. V.; Richardson, I. G.; Barbier, L. M.

    1991-01-01

    The abundances of energetic ions accelerated from high-speed solar wind streams by shock waves formed at corotating interaction regions (CIRs) where high-speed streams overtake the lower-speed solar wind are examined. The observed element abundances appear to represent those of the high-speed solar wind, unmodified by the shock acceleration. These abundances, relative to those in the solar photosphere, are organized by the first ionization potential (FIP) of the ions in a way that is different from the FIP effect commonly used to describe differences between abundances in the solar photosphere and those in the solar corona, solar energetic particles (SEPs), and the low-speed solar wind. In contrast, the FIP effect of the ion abundances in the CIR events is characterized by a smaller amplitude of the differences between high-FIP and low-FIP ions and by elevated abundances of He, C, and S.

  9. The static properties and form factors of the deuteron using the different forms of the Wood-Saxon potential

    NASA Astrophysics Data System (ADS)

    Rezaei, B.; Dashtimoghadam, A.

    2014-09-01

    The basic properties and form factors of the deuteron system are investigated for the different forms of the Wood-Saxon potential. We have used the Nikiforov-Uvarov (NU) method for analytical solution of the radial Schrodinger equation. A comparison of the calculated values with experimental results are given. It is shown that the obtained results for the modified form of the Wood-Saxon potential are very close to the experimental results in comparison with other forms of the potential.

  10. On the origin of the electrostatic potential difference at a liquid-vacuum interface

    PubMed Central

    Harder, Edward; Roux, Benoît

    2008-01-01

    The microscopic origin of the interface potential calculated from computer simulations is elucidated by considering a simple model of molecules near an interface. The model posits that molecules are isotropically oriented and their charge density is Gaussian distributed. Molecules that have a charge density that is more negative toward their interior tend to give rise to a negative interface potential relative to the gaseous phase, while charge densities more positive toward their interior give rise to a positive interface potential. The interface potential for the model is compared to the interface potential computed from molecular dynamics simulations of the nonpolar vacuum-methane system and the polar vacuum-water interface system. The computed vacuum-methane interface potential from a molecular dynamics simulation (−220 mV) is captured with quantitative precision by the model. For the vacuum-water interface system, the model predicts a potential of −400 mV compared to −510 mV, calculated from a molecular dynamics simulation. The physical implications of this isotropic contribution to the interface potential is examined using the example of ion solvation in liquid methane. PMID:19102551

  11. Chemical composition and bioethanol potential of different plant species found in pacific northwest conservation buffers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increase in energy demand has led towards considering lignocellulosic feedstocks as potential for ethanol production. Aim of this study was to estimate the potential of grass straws from conservation reserve program (CRP) lands as feedstocks for ethanol production. The CRP was initiated to ensure re...

  12. Comparison of Water Potentials Measured by In Situ Psychrometry and Pressure Chamber in Morphologically Different Species 1

    PubMed Central

    Turner, Neil C.; Spurway, R. A.; Schulze, E.-D.

    1984-01-01

    Leaf water potentials measured by in situ psychrometry were compared with leaf water potentials measured by the pressure chamber technique at various values of water potential in Helianthus annuus, Helianthus nuttallii, Vigna unguiculata, Nerium oleander, Pistacia vera, and Corylus avellana. In V. unguiculata, the leaf water potentials measured by the in situ psychrometer oscillated at the same periodicity as, and proportional to, the leaf conductance. In all species, potentials measured by in situ psychrometers operating in the psychrometric mode were linearly correlated with potentials measured with the pressure chamber. However, the in situ psychrometers underestimated the leaf water potential in the two Helianthus species at low water potentials and overestimated the water potential in P. vera, N. oleander, and C. avellana. The underestimation in the two Helianthus species at low water potentials resulted from differences in water potential across the leaf. The overestimation in P. vera, N. oleander, and C. avellana was considered to arise from low epidermal conductances in these species even after abrasion of the cuticle. Pressure-volume studies with Lycopersicon esculentum showed that less water was expressed from distal than proximal leaflets when the whole leaf was slowly pressurized. The implication of this for water relations characteristics obtained by pressure-volume techniques is discussed. We conclude that in situ psychrometers are suitable for following dynamic changes in leaf water potential, but should be used with caution on leaves with low epidermal conductances. PMID:16663415

  13. Event-Related Potential Responses to Beloved and Familiar Faces in Different Marriage Styles: Evidence from Mosuo Subjects.

    PubMed

    Wu, Haiyan; Luo, Li; Dai, Junqiang; Yang, Suyong; Wang, Naiyi; Luo, Yue-Jia

    2016-01-01

    Research on familiar face recognition has largely focused on the neural correlates of recognizing a beloved partner or family member. However, no research has explored the effect of marriage style on the recognition of a beloved partner's face, especially in matriarchal societies. Here, we examined the time course of event-related potentials (ERP) in response to the face of a beloved partner, sibling, or unknown person in a sample of individuals from the matriarchal Mosuo tribe. Two groups were assessed: intermarriage and walking marriage groups (i.e., couples in a committed relationship who do not cohabitate during the daytime). In agreement with previous reports, ERP results revealed more positive VPP, N250, and P300 waveforms for beloved faces than sibling faces in both groups. Moreover, P300 was more positive for beloved partner versus sibling faces; however, this difference emerged at fronto-central sites for the walking marriage group and at posterior sites for the intermarriage group. Overall, we observed that marriage style affects the later stage processing of a beloved partner's face, and this may be associated with greater affective arousal and familiarity. PMID:26925002

  14. Event-Related Potential Responses to Beloved and Familiar Faces in Different Marriage Styles: Evidence from Mosuo Subjects

    PubMed Central

    Wu, Haiyan; Luo, Li; Dai, Junqiang; Yang, Suyong; Wang, Naiyi; Luo, Yue-jia

    2016-01-01

    Research on familiar face recognition has largely focused on the neural correlates of recognizing a beloved partner or family member. However, no research has explored the effect of marriage style on the recognition of a beloved partner’s face, especially in matriarchal societies. Here, we examined the time course of event-related potentials (ERP) in response to the face of a beloved partner, sibling, or unknown person in a sample of individuals from the matriarchal Mosuo tribe. Two groups were assessed: intermarriage and walking marriage groups (i.e., couples in a committed relationship who do not cohabitate during the daytime). In agreement with previous reports, ERP results revealed more positive VPP, N250, and P300 waveforms for beloved faces than sibling faces in both groups. Moreover, P300 was more positive for beloved partner versus sibling faces; however, this difference emerged at fronto-central sites for the walking marriage group and at posterior sites for the intermarriage group. Overall, we observed that marriage style affects the later stage processing of a beloved partner’s face, and this may be associated with greater affective arousal and familiarity. PMID:26925002

  15. A Large Scale (N=400) Investigation of Gray Matter Differences in Schizophrenia Using Optimized Voxel-based Morphometry

    PubMed Central

    Meda, Shashwath A.; Giuliani, Nicole R.; Calhoun, Vince D.; Jagannathan, Kanchana; Schretlen, David J.; Pulver, Anne; Cascella, Nicola; Keshavan, Matcheri; Kates, Wendy; Buchanan, Robert; Sharma, Tonmoy; Pearlson, Godfrey D.

    2008-01-01

    Background Many studies have employed voxel-based morphometry (VBM) of MRI images as an automated method of investigating cortical gray matter differences in schizophrenia. However, results from these studies vary widely, likely due to different methodological or statistical approaches. Objective To use VBM to investigate gray matter differences in schizophrenia in a sample significantly larger than any published to date, and to increase statistical power sufficiently to reveal differences missed in smaller analyses. Methods Magnetic resonance whole brain images were acquired from four geographic sites, all using the same model 1.5T scanner and software version, and combined to form a sample of 200 patients with both first episode and chronic schizophrenia and 200 healthy controls, matched for age, gender and scanner location. Gray matter concentration was assessed and compared using optimized VBM. Results Compared to the healthy controls, schizophrenia patients showed significantly less gray matter concentration in multiple cortical and subcortical regions, some previously unreported. Overall, we found lower concentrations of gray matter in regions identified in prior studies, most of which reported only subsets of the affected areas. Conclusions Gray matter differences in schizophrenia are most comprehensively elucidated using a large, diverse and representative sample. PMID:18378428

  16. Systems Perturbation Analysis of a Large-Scale Signal Transduction Model Reveals Potentially Influential Candidates for Cancer Therapeutics.

    PubMed

    Puniya, Bhanwar Lal; Allen, Laura; Hochfelder, Colleen; Majumder, Mahbubul; Helikar, Tomáš

    2016-01-01

    -related components and tumor-suppressor genes, suggesting that this combinatorial perturbation may lead to a better target for decreasing cell proliferation and inducing apoptosis. Finally, our approach shows a potential to identify and prioritize therapeutic targets through systemic perturbation analysis of large-scale computational models of signal transduction. Although some components of the presented computational results have been validated against independent gene expression data sets, more laboratory experiments are warranted to more comprehensively validate the presented results. PMID:26904540

  17. Considerations for Probabilistic Analyses to Assess Potential Changes to Large-Break LOCA Definition for ECCS Requirements

    SciTech Connect

    Wilkowski, G.; Rudland, D.; Wolterman, R.; Krishnaswamy, P.; Scott, P.; Rahman, S.; Fairbanks, C.

    2002-07-01

    The U.S.NRC has undertaken a study to explore changes to the body of Part 50 of the U.S. Federal Code of Regulations, to incorporate risk-informed attributes. One of the regulations selected for this study is 10 CFR 50.46, {sup A}cceptance Criteria for Emergency Core Cooling Systems for Light-Water Nuclear Power Reactors{sup .} These changes will potentially enhance safety and reduce unnecessary burden on utilities. Specific attention is being paid to redefining the maximum pipe break size for LB-LOCA by determining the spectrum of pipe diameter (or equivalent opening area) versus failure probabilities. In this regard, it is necessary to ensure that all contributors to probabilistic failures are accounted for when redefining ECCS requirements. This paper describes initial efforts being conducted for the U.S.NRC on redefining the LB-LOCA requirements. Consideration of the major contributors to probabilistic failure, and deterministic aspects for modeling them, are being addressed. At this time three major contributors to probabilistic failures are being considered. These include: (1) Analyses of the failure probability from cracking mechanisms that could involve rupture or large opening areas from either through-wall or surface flaws, whether the pipe system was approved for leak-before-break (LBB) or not. (2) Future degradation mechanisms, such as recent occurrence of PWSCC in PWR piping need to be included. This degradation mechanism was not recognized as being an issue when LBB was approved for many plants or when the initial risk-informed inspection plans were developed. (3) Other indirect causes of loss of pressure-boundary integrity than from cracks in the pipe system also should be included. The failure probability from probabilistic fracture mechanics will not account for these other indirect causes that could result in a large opening in the pressure boundary: i.e., failure of bolts on a steam generator manway, flanges, and valves; outside force damage from

  18. Systems Perturbation Analysis of a Large-Scale Signal Transduction Model Reveals Potentially Influential Candidates for Cancer Therapeutics

    PubMed Central

    Puniya, Bhanwar Lal; Allen, Laura; Hochfelder, Colleen; Majumder, Mahbubul; Helikar, Tomáš

    2016-01-01

    -related components and tumor-suppressor genes, suggesting that this combinatorial perturbation may lead to a better target for decreasing cell proliferation and inducing apoptosis. Finally, our approach shows a potential to identify and prioritize therapeutic targets through systemic perturbation analysis of large-scale computational models of signal transduction. Although some components of the presented computational results have been validated against independent gene expression data sets, more laboratory experiments are warranted to more comprehensively validate the presented results. PMID:26904540

  19. Thrombin mitogenic responses and protein phosphorylation are different in cultured human endothelial cells derived from large and microvessels

    SciTech Connect

    Dupuy, E.; Bikfalvi, A.; Rendu, F.; Toledano, S.L.; Tobelem, G. )

    1989-12-01

    It is well established that thrombin induces various biological responses in endothelial cells derived from large vessels. However, little is known about the effects of thrombin on the microvasculature. Protein phosphorylation may be one of the mechanisms by which an extracellular stimulus initiates cellular events like proliferation. Therefore, we have compared the effects of either human alpha-thrombin or phorbol esters (TPA) on the proliferation or protein phosphorylation in endothelial cells derived from large vessels (umbilical vein, HUVEC) or microvessels (omental tissue, HOMEC). In HOMEC, thrombin did not stimulate cell proliferation and protein phosphorylation while TPA slightly reduced the cell proliferation and induced the phosphorylation of a 27-kDa protein. In contrast, in HUVEC, thrombin or TPA markedly enhanced the cell proliferation and stimulated the phosphorylation of a 59-kDa protein. These data indicate that endothelial cells from large and small vessels respond differently to thrombin and there is a complex and as yet unclear relationship between the proliferation and the protein phosphorylation induced by thrombin.

  20. Altitude distribution of the auroral acceleration potential determined from cluster satellite data at different heights.

    PubMed

    Marklund, Göran T; Sadeghi, Soheil; Karlsson, Tomas; Lindqvist, Per-Arne; Nilsson, Hans; Forsyth, Colin; Fazakerley, Andrew; Lucek, Elizabeth A; Pickett, Jolene

    2011-02-01

    Aurora, commonly seen in the polar sky, is a ubiquitous phenomenon occurring on Earth and other solar system planets. The colorful emissions are caused by electron beams hitting the upper atmosphere, after being accelerated by quasistatic electric fields at 1-2 R(E) altitudes, or by wave electric fields. Although aurora was studied by many past satellite missions, Cluster is the first to explore the auroral acceleration region with multiprobes. Here, Cluster data are used to determine the acceleration potential above the aurora and to address its stability in space and time. The derived potential comprises two upper, broad U-shaped potentials and a narrower S-shaped potential below, and is stable on a 5 min time scale. The scale size of the electric field relative to that of the current is shown to depend strongly on altitude within the acceleration region. To reveal these features was possible only by combining data from the two satellites. PMID:21405403

  1. Water models based on a single potential energy surface and different molecular degrees of freedom

    NASA Astrophysics Data System (ADS)

    Saint-Martin, Humberto; Hernández-Cobos, Jorge; Ortega-Blake, Iván

    2005-06-01

    Up to now it has not been possible to neatly assess whether a deficient performance of a model is due to poor parametrization of the force field or the lack of inclusion of enough molecular properties. This work compares several molecular models in the framework of the same force field, which was designed to include many-body nonadditive effects: (a) a polarizable and flexible molecule with constraints that account for the quantal nature of the vibration [B. Hess, H. Saint-Martin, and H. J. C. Berendsen, J. Chem. Phys. 116, 9602 (2002), H. Saint-Martin, B. Hess, and H. J. C. Berendsen, J. Chem. Phys. 120, 11133 (2004)], (b) a polarizable and classically flexible molecule [H. Saint-Martin, J. Hernández-Cobos, M. I. Bernal-Uruchurtu, I. Ortega-Blake, and H. J. C. Berendsen, J. Chem. Phys. 113, 10899 (2000)], (c) a polarizable and rigid molecule, and finally (d) a nonpolarizable and rigid molecule. The goal is to determine how significant the different molecular properties are. The results indicate that all factors—nonadditivity, polarizability, and intramolecular flexibility—are important. Still, approximations can be made in order to diminish the computational cost of the simulations with a small decrease in the accuracy of the predictions, provided that those approximations are counterbalanced by the proper inclusion of an effective molecular property, that is, an average molecular geometry or an average dipole. Hence instead of building an effective force field by parametrizing it in order to reproduce the properties of a specific phase, a building approach is proposed that is based on adequately restricting the molecular flexibility and/or polarizability of a model potential fitted to unimolecular properties, pair interactions, and many-body nonadditive contributions. In this manner, the same parental model can be used to simulate the same substance under a wide range of thermodynamic conditions. An additional advantage of this approach is that, as the force

  2. A priori tests of a new dynamic subgrid-scale model for finite-difference large-eddy simulations

    NASA Astrophysics Data System (ADS)

    Salvetti, M. V.; Banerjee, S.

    1995-11-01

    This work focuses on subgrid-scale (SGS) modeling for finite-difference large-eddy simulations, employing filters in physical space. When a filter in physical space is used, an overlap is allowed between the unresolved and the resolved scales. For such a filter, all the three terms in the classical decomposition of the SGS stress tensor are present: the Leonard and cross-terms, due to the overlap between scales, and the true SGS Reynolds tensor, expressing the pure effect of the small scales. A dynamic subgrid-scale stress model is proposed, for finite-difference large-eddy simulation of incompressible and compressible flows in which the Leonard and cross-parts of the SGS stress tensor are assumed to be proportional to the resolved part (the ``modified Leonard term''), which is computed explicity. The SGS Reynolds stress is modeled by the eddy-viscosity Smagorinsky model. The two unknown parameters in this model are computed dynamically, as in Germano et al. [Phys. Fluids A 3, 1790 (1991)], but using a least squares technique. The model is tested using direct numerical simulation data for fully developed turbulent incompressible flows in presence of solid boundaries and free surfaces, and for compressible homogeneous turbulence. A ``box filter'' in physical space is used. Other SGS models are also tested, viz. the dynamic model of Germano et al. (DSM), and its compressible extension by Moin et al. [Phys. Fluids A 3, 2746 (1991)], and the dynamic mixed model in Zang et al. [Phys. Fluids A 5, 3186 (1993)] (DMM) and its compressible version developed here. Results on the behavior of the different models with regard to energy exchanges and correlation with the exact SGS stresses are presented for different filter widths. In particular high correlation is found between the modified Leonard and cross-terms thus justifying the basic assumption made in the model.

  3. Estimating the Potential Impacts of Large Mesopredators on Benthic Resources: Integrative Assessment of Spotted Eagle Ray Foraging Ecology in Bermuda

    PubMed Central

    Ajemian, Matthew J.; Powers, Sean P.; Murdoch, Thaddeus J. T.

    2012-01-01

    Declines of large sharks and subsequent release of elasmobranch mesopredators (smaller sharks and rays) may pose problems for marine fisheries management as some mesopredators consume exploitable shellfish species. The spotted eagle ray (Aetobatus narinari) is the most abundant inshore elasmobranch in subtropical Bermuda, but its predatory role remains unexamined despite suspected abundance increases and its hypothesized specialization for mollusks. We utilized a combination of acoustic telemetry, benthic invertebrate sampling, gut content analysis and manipulative experiments to assess the impact of spotted eagle rays on Bermudian shellfish resources. Residency and distribution of adult spotted eagle rays was monitored over two consecutive summers in Harrington Sound (HS), an enclosed inshore lagoon that has historically supported multiple recreational and commercial shellfish species. Telemetered rays exhibited variable fidelity (depending on sex) to HS, though generally selected regions that supported relatively high densities of potential mollusk prey. Gut content analysis from rays collected in HS revealed a diet of mainly bivalves and a few gastropods, with calico clam (Macrocallista maculata) representing the most important prey item. Manipulative field and mesocosm experiments with calico clams suggested that rays selected prey patches based on density, though there was no evidence of rays depleting clam patches to extirpation. Overall, spotted eagle rays had modest impacts on local shellfish populations at current population levels, suggesting a reduced role in transmitting cascading effects from apex predator loss. However, due to the strong degree of coupling between rays and multiple protected mollusks in HS, ecosystem-based management that accounts for ray predation should be adopted. PMID:22802956

  4. Estimating the potential impacts of large mesopredators on benthic resources: integrative assessment of spotted eagle ray foraging ecology in Bermuda.

    PubMed

    Ajemian, Matthew J; Powers, Sean P; Murdoch, Thaddeus J T

    2012-01-01

    Declines of large sharks and subsequent release of elasmobranch mesopredators (smaller sharks and rays) may pose problems for marine fisheries management as some mesopredators consume exploitable shellfish species. The spotted eagle ray (Aetobatus narinari) is the most abundant inshore elasmobranch in subtropical Bermuda, but its predatory role remains unexamined despite suspected abundance increases and its hypothesized specialization for mollusks. We utilized a combination of acoustic telemetry, benthic invertebrate sampling, gut content analysis and manipulative experiments to assess the impact of spotted eagle rays on Bermudian shellfish resources. Residency and distribution of adult spotted eagle rays was monitored over two consecutive summers in Harrington Sound (HS), an enclosed inshore lagoon that has historically supported multiple recreational and commercial shellfish species. Telemetered rays exhibited variable fidelity (depending on sex) to HS, though generally selected regions that supported relatively high densities of potential mollusk prey. Gut content analysis from rays collected in HS revealed a diet of mainly bivalves and a few gastropods, with calico clam (Macrocallista maculata) representing the most important prey item. Manipulative field and mesocosm experiments with calico clams suggested that rays selected prey patches based on density, though there was no evidence of rays depleting clam patches to extirpation. Overall, spotted eagle rays had modest impacts on local shellfish populations at current population levels, suggesting a reduced role in transmitting cascading effects from apex predator loss. However, due to the strong degree of coupling between rays and multiple protected mollusks in HS, ecosystem-based management that accounts for ray predation should be adopted. PMID:22802956

  5. Balance and Strength - Estimating the Maximum Prey-Lifting Potential of the Large Predatory Dinosaur Carcharodontosaurus saharicus.

    PubMed

    Henderson, Donald M; Nicholls, Robert

    2015-08-01

    Motivated by the work of palaeo-art "Double Death (2011)," a biomechanical analysis using three-dimensional digital models was conducted to assess the potential of a pair of the large, Late Cretaceous theropod dinosaur Carcharodontosaurus saharicus to successfully lift a medium-sized sauropod and not lose balance. Limaysaurus tessonei from the Late Cretaceous of South America was chosen as the sauropod as it is more completely known, but closely related to the rebbachisaurid sauropods found in the same deposits with C. saharicus. The body models incorporate the details of the low-density regions associated with lungs, systems of air sacs, and pneumatized axial skeletal regions. These details, along with the surface meshes of the models, were used to estimate the body masses and centers of mass of the two animals. It was found that a 6 t C. saharicus could successfully lift a mass of 2.5 t and not lose balance as the combined center of mass of the body and the load in the jaws would still be over the feet. However, the neck muscles were found to only be capable of producing enough force to hold up the head with an added mass of 424 kg held at the midpoint of the maxillary tooth row. The jaw adductor muscles were more powerful, and could have held a load of 512 kg. The more limiting neck constraint leads to the conclusion that two, adult C. saharicus could successfully lift a L. tessonei with a maximum body mass of 850 kg and a body length of 8.3 m. PMID:25884664

  6. Characterizing abnormal behavior in a large population of zoo-housed chimpanzees: prevalence and potential influencing factors.

    PubMed

    Jacobson, Sarah L; Ross, Stephen R; Bloomsmith, Mollie A

    2016-01-01

    Abnormal behaviors in captive animals are generally defined as behaviors that are atypical for the species and are often considered to be indicators of poor welfare. Although some abnormal behaviors have been empirically linked to conditions related to elevated stress and compromised welfare in primates, others have little or no evidence on which to base such a relationship. The objective of this study was to investigate a recent claim that abnormal behavior is endemic in the captive population by surveying a broad sample of chimpanzees (Pan troglodytes), while also considering factors associated with the origins of these behaviors. We surveyed animal care staff from 26 accredited zoos to assess the prevalence of abnormal behavior in a large sample of chimpanzees in the United States for which we had information on origin and rearing history. Our results demonstrated that 64% of this sample was reported to engage in some form of abnormal behavior in the past two years and 48% of chimpanzees engaged in abnormal behavior other than coprophagy. Logistic regression models were used to analyze the historical variables that best predicted the occurrence of all abnormal behavior, any abnormal behavior that was not coprophagy, and coprophagy. Rearing had opposing effects on the occurrence of coprophagy and the other abnormal behaviors such that mother-reared individuals were more likely to perform coprophagy, whereas non-mother-reared individuals were more likely to perform other abnormal behaviors. These results support the assertion that coprophagy may be classified separately when assessing abnormal behavior and the welfare of captive chimpanzees. This robust evaluation of the prevalence of abnormal behavior in our sample from the U.S. zoo population also demonstrates the importance of considering the contribution of historical variables to present behavior, in order to better understand the causes of these behaviors and any potential relationship to psychological

  7. Characterizing abnormal behavior in a large population of zoo-housed chimpanzees: prevalence and potential influencing factors

    PubMed Central

    Jacobson, Sarah L.; Bloomsmith, Mollie A.

    2016-01-01

    Abnormal behaviors in captive animals are generally defined as behaviors that are atypical for the species and are often considered to be indicators of poor welfare. Although some abnormal behaviors have been empirically linked to conditions related to elevated stress and compromised welfare in primates, others have little or no evidence on which to base such a relationship. The objective of this study was to investigate a recent claim that abnormal behavior is endemic in the captive population by surveying a broad sample of chimpanzees (Pan troglodytes), while also considering factors associated with the origins of these behaviors. We surveyed animal care staff from 26 accredited zoos to assess the prevalence of abnormal behavior in a large sample of chimpanzees in the United States for which we had information on origin and rearing history. Our results demonstrated that 64% of this sample was reported to engage in some form of abnormal behavior in the past two years and 48% of chimpanzees engaged in abnormal behavior other than coprophagy. Logistic regression models were used to analyze the historical variables that best predicted the occurrence of all abnormal behavior, any abnormal behavior that was not coprophagy, and coprophagy. Rearing had opposing effects on the occurrence of coprophagy and the other abnormal behaviors such that mother-reared individuals were more likely to perform coprophagy, whereas non-mother-reared individuals were more likely to perform other abnormal behaviors. These results support the assertion that coprophagy may be classified separately when assessing abnormal behavior and the welfare of captive chimpanzees. This robust evaluation of the prevalence of abnormal behavior in our sample from the U.S. zoo population also demonstrates the importance of considering the contribution of historical variables to present behavior, in order to better understand the causes of these behaviors and any potential relationship to psychological

  8. A large survey of Croatian wild mammals for Giardia duodenalis reveals a low prevalence and limited zoonotic potential.

    PubMed

    Beck, Relja; Sprong, Hein; Lucinger, Snjezana; Pozio, Edoardo; Cacciò, Simone M

    2011-08-01

    Wild mammals are considered an important source of potentially zoonotic Giardia duodenalis parasites, yet surprisingly little information is available on the actual prevalence and the genetic identity of the species they harbor. A large survey was conducted in Croatia by collecting 832 fecal samples from red deer (Cervus elaphus, n = 374), roe deer (Capreolus capreolus, n = 21), wild boars (Sus scrofa, n = 144), foxes (Vulpes vulpes, n = 66), bears (Ursus arctos, n = 19), wolves (Canis lupus, n = 127), jackals (Canis aureus, n = 8), and hares (Lepus europeus, n = 73). Fecal samples were tested for the presence of Giardia cysts using fluorescent microscopy. The observed prevalence ranged from low (1% in red deer, 1.7% in wild boars, and 4.5% in foxes) to moderate (10% in wolves and 12.5% in jackals) to high (24% in roe deer). No cysts were observed in bears and hares. Polymerase chain reaction was performed on microscopically positive samples to amplify fragments of the small subunit ribosomal gene, the ribosomal 5.8S gene and the two flanking internal transcribed sequences, and the triose phosphate isomerase gene. Sequence analysis showed a predominance of G. duodenalis assemblage A in both ruminants (genotypes A1 and A3) and carnivores (genotype A1). G. duodenalis assemblages B, C, and D, as well as Giardia microti, were also detected in this study. This is the first molecular description of the parasite from the red deer, the wolf, and the jackal. The data point to a minor role of wild mammals as reservoirs of zoonotic assemblages of G. duodenalis, albeit cycling between sylvatic and domestic animals is possible. PMID:21142957

  9. A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts

    PubMed Central

    Smith, Craig R.; Grange, Laura J.; Honig, David L.; Naudts, Lieven; Huber, Bruce; Guidi, Lionel; Domack, Eugene

    2012-01-01

    Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km−2 and a population size of 1.55 × 106 in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430–725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr−1; if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400–600 m depths) within 1–2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems. PMID:21900324

  10. The HyperHydro (H2) experiment for comparing different large-scale models at various resolutions

    NASA Astrophysics Data System (ADS)

    Sutanudjaja, Edwin

    2016-04-01

    HyperHydro (http://www.hyperhydro.org/) is an open network of scientists with the objective of simulating large-scale terrestrial hydrology and water resources at hyper-resolution (Wood et al., 2011, DOI: 10.1029/2010WR010090; Bierkens et al., 2014, DOI: 10.1002/hyp.10391). Within the HyperHydro network, a modeling workshop was held at Utrecht University, the Netherlands, on 9-12 June 2015. The goal of the workshop was to start the HyperHydro (H^2) experiment for comparing different large-scale hydrological models, at different spatial resolutions, from 50 km to 1 km. Model simulation results (e.g. discharge, soil moisture, evaporation, snow, groundwater depth, etc.) are evaluated to available observation data and compared across various models and resolutions. At EGU 2016, we would like to present the latest results of this inter-comparison experiment. We also invite participation from the hydrology community on this experiment. Up to now, the models compared are CLM, LISFLOOD, mHM, ParFlow-CLM, PCR-GLOBWB, TerrSysMP, VIC, WaterGAP, and wflow. As initial test-beds, we mainly focus on two river basins: San Joaquin/California (82000 km^2) and Rhine (185000 km^2). Moreover, comparison at a larger region, such for the CONUS (Contiguous-US) domain, is also explored and presented.

  11. The HyperHydro (H^2) experiment for comparing different large-scale models at various resolutions

    NASA Astrophysics Data System (ADS)

    Sutanudjaja, E.; Bosmans, J.; Chaney, N.; Clark, M. P.; Condon, L. E.; David, C. H.; De Roo, A. P. J.; Doll, P. M.; Drost, N.; Eisner, S.; Famiglietti, J. S.; Floerke, M.; Gilbert, J. M.; Gochis, D. J.; Hut, R.; Keune, J.; Kollet, S. J.; Maxwell, R. M.; Pan, M.; Rakovec, O.; Reager, J. T., II; Samaniego, L. E.; Mueller Schmied, H.; Trautmann, T.; Van Beek, L. P.; Van De Giesen, N.; Wood, E. F.; Bierkens, M. F.; Kumar, R.

    2015-12-01

    HyperHydro (http://www.hyperhydro.org/) is an open network of scientists with the objective of simulating large-scale terrestrial hydrology and water resources at hyper-resolution (Bierkens et al., 2014, DOI: 10.1002/hyp.10391). Within the HyperHydro network, a modeling workshop was held at Utrecht University, the Netherlands, on 9-12 June 2015. The goal of the workshop was to start the HyperHydro (H^2) experiment for comparing different large-scale hydrological models, at different spatial resolutions, from 50 km to 1 km. Model simulation results (e.g. discharge, soil moisture, evaporation, snow, groundwater depth, etc.) are evaluated to available observation data and compared across various models and resolutions. In AGU 2015, we would like to present the results of this inter-comparison experiment. During the workshop in Utrecht, the models compared were CLM, LISFLOOD, mHM, ParFlow-CLM, PCR-GLOBWB, TerrSysMP, VIC and WaterGAP. We invite participation from the hydrology community on this experiment. As test-beds, we focus on two river basins: San Joaquin (~82000 km2) and Rhine (~185000 km2). In the near future, we will escalate this experiment to the CONUS and CORDEX-EU domains. The picture below was taken during the workshop in Utrecht (9-12 June 2015).

  12. Potential impact of atmospheric N deposition on soil N2O emission varies with different soil N regimes

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Yi, M.; Koike, T.

    2011-12-01

    Future increases in nitrogen (N) deposition has the potential to change belowground nutrient dynamics, especially N cycle, and thereby can alter the soil-atmosphere exchange of nitrous oxide (N2O) which is one of the major greenhouse gases. Moreover, we considered that their effect on soil N2O emission varies with different soil N levels because N2O is a by-product of the biological nitrification process in aerobic soil environments and of the biological denitrification process in anaerobic soil environments. To understand the changes in soil N2O flux under different soil N, we carried out simulated N addition experiment in three-year-old hybrid larch F1 (F1: Larix gmelinii var. japonica × Larix kaempferi) plantation during two growing seasons 2008 - 2009. The hybrid larch F1 was developed to make up for several problems of larch species, e.g. a high susceptibility to disease or grazing damage by insects and fungi, and a large number of this seedlings are planted recently in northern Japan. Based on soil analysis, we selected two sites which have different soil N concentration, i.e. low-N and high-N concentrations. Nitrogen input was initiated at the onset of our experiment, and included four treatments with four replications: Low-N soil + Zero-N control, Low-N soil + 50 kg-N addition, High-N soil + Zero-N control and High-N soil + 50 kg-N addition. The N was added as ammonium nitrate (NH4NO3) solution distributed in four occasions during each growing season. Gas and soil samples were taken from each plot on ten occasions at a time during each growing season. Collected N2O concentrations were determined by a gas chromatograph (GC-14B; Shimadzu, Kyoto, Japan) equipped with an electron capture detector, while total-N and inorganic-N concentrations were obtained by a NC analyzer (Sumigraph NC-1000; Sumica Chemical Analysis Service Ltd., Osaka, Japan) and an auto analyzer (AACS-4; BL-TEC Inc., Osaka, Japan), respectively. Before the N addition, initial total-N in High

  13. Differences Between a Single- and a Double-Folding Nucleus-^{9}Be Optical Potential

    NASA Astrophysics Data System (ADS)

    Bonaccorso, A.; Carstoiu, F.; Charity, R. J.; Kumar, R.; Salvioni, G.

    2016-05-01

    We have recently constructed two very successful n-^9Be optical potentials (Bonaccorso and Charity in Phys Rev C89:024619, 2014). One by the Dispersive Optical Model (DOM) method and the other (AB) fully phenomenological. The two potentials have strong surface terms in common for both the real and the imaginary parts. This feature makes them particularly suitable to build a single-folded (light-) nucleus-^9Be optical potential by using ab-initio projectile densities such as those obtained with the VMC method (Wiringa http://www.phy.anl.gov/theory/research/density/). On the other hand, a VMC density together with experimental nucleon-nucleon cross-sections can be used also to obtain a neutron and/or proton-^9Be imaginary folding potential. We will use here an ab-initio VMC density (Wiringa http://www.phy.anl.gov/theory/research/density/) to obtain both a n-^9Be single-folded potential and a nucleus-nucleus double-folded potential. In this work we report on the cases of ^8B, ^8Li and ^8C projectiles. Our approach could be the basis for a systematic study of optical potentials for light exotic nuclei scattering on such light targets. Some of the projectiles studied are cores of other exotic nuclei for which neutron knockout has been used to extract spectroscopic information. For those cases, our study will serve to make a quantitative assessment of the core-target part of the reaction description, in particular its localization.

  14. THE STRUCTURE OF PRE-TRANSITIONAL PROTOPLANETARY DISKS. II. AZIMUTHAL ASYMMETRIES, DIFFERENT RADIAL DISTRIBUTIONS OF LARGE AND SMALL DUST GRAINS IN PDS 70 {sup ,}

    SciTech Connect

    Hashimoto, J.; Wisniewski, J.; Tsukagoshi, T.; Brown, J. M.; Dong, R.; Muto, T.; Zhu, Z.; Ohashi, N.; Kudo, T.; Egner, S.; Guyon, O.; Kusakabe, N.; Akiyama, E.; Abe, L.; Brandner, W.; Carson, J.; Feldt, M.; Brandt, T.; Currie, T.; Grady, C. A.; and others

    2015-01-20

    The formation scenario of a gapped disk, i.e., transitional disk, and its asymmetry is still under debate. Proposed scenarios such as disk-planet interaction, photoevaporation, grain growth, anticyclonic vortex, eccentricity, and their combinations would result in different radial distributions of the gas and the small (sub-μm size) and large (millimeter size) dust grains as well as asymmetric structures in a disk. Optical/near-infrared (NIR) imaging observations and (sub-)millimeter interferometry can trace small and large dust grains, respectively; therefore multi-wavelength observations could help elucidate the origin of complicated structures of a disk. Here we report Submillimeter Array observations of the dust continuum at 1.3 mm and {sup 12}CO J = 2 → 1 line emission of the pre-transitional protoplanetary disk around the solar-mass star PDS 70. PDS 70, a weak-lined T Tauri star, exhibits a gap in the scattered light from its disk with a radius of ∼65 AU at NIR wavelengths. However, we found a larger gap in the disk with a radius of ∼80 AU at 1.3 mm. Emission from all three disk components (the gas and the small and large dust grains) in images exhibits a deficit in brightness in the central region of the disk, in particular, the dust disk in small and large dust grains has asymmetric brightness. The contrast ratio of the flux density in the dust continuum between the peak position to the opposite side of the disk reaches 1.4. We suggest the asymmetries and different gap radii of the disk around PDS 70 are potentially formed by several (unseen) accreting planets inducing dust filtration.