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Sample records for counterion distribution contribute

  1. Influence of higher valent ions on flexible polyelectrolyte stiffness and counter-ion distribution.

    Science.gov (United States)

    Chremos, Alexandros; Douglas, Jack F

    2016-04-28

    We investigate the influence of counter-ion valency on the flexibility of highly charged flexible polymer chains using molecular dynamics simulations that include both salt and an explicit solvent. As observed experimentally, we find that divalent counter-ions greatly reduce the chain persistence length, lp, in comparison with monovalent counter-ions. On the other hand, polyelectrolyte chains having trivalent counter-ions adopt a much more compact conformation than polyelectrolytes having monovalent and divalent counter-ions. We demonstrate that the tendency of polyelectrolyte chains to become deformed by proximal high valence counter-ions is due to chain "coiling" around the counter-ions. In particular, we find that the number of contacts that the proximal counter-ions have with the polyelectrolyte dictates the extent of chain coiling. This ion-binding induced coiling mechanism influences not only the conformational properties of the polyelectrolyte, but also the counter-ion distribution around the chain. Specifically, we find that higher valent counter-ions lead both to a counter-ion enrichment in close proximity to the polyelectrolyte and to a significant reduction in the spatial extent of the diffuse counter-ion cloud around the polyelectrolyte.

  2. Molecular size distribution of compost-derived humates as a function of concentration and different counterions.

    Science.gov (United States)

    Maia, Claudia M B F; Piccolo, Alessandro; Mangrich, Antonio S

    2008-11-01

    Conformational changes in the structures of humic acids (HA) extracted from compost with varying degrees of maturity were monitored by high performance size exclusion chromatography (HPSEC). The molecular size distribution of HA was compared in solutions containing sodium or ammonium counterions at pH 7 and pH 4.5. These findings indicate that the humates' molecular size depended not only on the nature of the counterions but also on their concentration in the solution. The physicochemical nature of sodium counterions determined smaller molecular sizes than those of the more hydrated ammonium counterions, at low concentrations of humates. Conversely, at higher humate concentrations, the more compact conformation of sodium humates produced larger molecular sizes than those of ammonium humates due to the aggregation of more hydrophobic surfaces in the sodium humates. Composting led to the degradation of labile microbial components with accumulation of hydrophobic constituents. This caused self-association of hydrophobic compounds into humic superstructures of larger molecular size over composting time. At lower pH, changes in conformational stability by the addition of acetic acid to humate solutions were explained by the supramolecular model of humified organic matter.

  3. Distribution of counterions and interaction between two similarly charged dielectric slabs: roles of charge discreteness and dielectric inhomogeneity.

    Science.gov (United States)

    Pezeshkian, Weria; Nikoofard, Narges; Norouzi, Davood; Mohammad-Rafiee, Farshid; Fazli, Hossein

    2012-06-01

    The distribution of counterions and the electrostatic interaction between two similarly charged dielectric slabs is studied in the strong coupling limit. Dielectric inhomogeneities and discreteness of charge on the slabs have been taken into account. It is found that the amount of dielectric constant difference between the slabs and the environment, and the discreteness of charge on the slabs have opposing effects on the equilibrium distribution of the counterions. At small interslab separations, increasing the amount of dielectric constant difference increases the tendency of the counterions toward the middle of the intersurface space between the slabs and the discreteness of charge pushes them to the surfaces of the slabs. In the limit of point charges, independent of the strength of dielectric inhomogeneity, counterions distribute near the surfaces of the slabs. The interaction between the slabs is attractive at low temperatures and its strength increases with the dielectric constant difference. At room temperature, the slabs may completely attract each other, reach to an equilibrium separation, or have two equilibrium separations with a barrier in between, depending on the system parameters.

  4. Single chains of strong polyelectrolytes in aqueous solutions at extreme dilution: Conformation and counterion distribution

    Science.gov (United States)

    Xu, Guofeng; Luo, Shuangjiang; Yang, Qingbo; Yang, Jingfa; Zhao, Jiang

    2016-10-01

    The molecular conformation of two typical polyelectrolytes, sodium polystyrene sulfonate (NaPSS) and quarternized poly-4-vinylpyridine (QP4VP), was studied in aqueous solutions without salt addition at the single molecular level. By fluorescence correlation spectroscopy, the hydrodynamic radius (Rh) of NaPSS and QP4VP with the molecular weight ranging more than one order of magnitude was measured. The scaling analysis of Rh exhibits scaling exponent of 0.70 and 0.86 for NaPSS and QP4VP in solutions without added salts, respectively, showing the conformation is much more expanded than random coil. Numerical fittings using the model of diffusion of a rod molecule agree with the data well, indicating that the polyelectrolyte chains take the rod-like conformation under the condition without salt addition. Further investigations by determining the electric potential of single PSS- chains using the photon counting histogram technique demonstrate the enhanced counterion adsorption to the charged chain at higher molecular weight.

  5. Distribution and Adsorption of Ionic Species into a Liposome Membrane and Their Dependence upon the Species and Concentration of a Coexisting Counterion.

    Science.gov (United States)

    Murakami, Koji; Hori, Kisho; Maeda, Kohji; Fukuyama, Mao; Yoshida, Yumi

    2016-10-10

    The distribution of ions into a bilayer lipid membrane (BLM) and their adsorption on the BLM are investigated by extracting a hydrophobic cation, rhodamine 6G (R6G(+)), into a liposome through the dialysis membrane method. R6G(+) distribution mainly depends upon the concentration of the coexisting anion and its species (Cl(-), Br(-), BF4(-), ClO4(-), and picrate). On the other hand, R6G(+) adsorption on the BLM surface follows the Langmuir adsorption model and is independent of the coexisting anion in the aqueous phase. We propose an extraction model of ionic species into the BLM, to explain the dependence of extraction of ionic species upon the coexisting anion. In this model, an ion is distributed with a coexisting counterion into the BLM and then forms an ion pair in the BLM. Here, the ion adsorption equilibrium on the BLM surface is independent of the species and concentration of the coexisting counterion under the same ionic strength. On the basis of this model, we estimate the distribution constant of R6G(+) and anion (KD), the ion-pair formation constant in the BLM (Kip), and the R6G(+) adsorption constant on the BLM surface (Kad). Even for an ultrathin membrane system, such as a BLM, R6G(+) is distributed with a coexisting counterion and the distribution equilibrium of the ionic species at the water-BLM interface is analyzable similar to that at the water-organic solvent interface.

  6. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, Maria, E-mail: mfr@fct.unl.pt; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Ferreira, Quirina [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Instituto de Telecomunicações, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Botelho do Rego, Ana Maria [Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa (Portugal)

    2015-09-21

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior.

  7. Modeling the construction of polymeric adsorbent media: Effects of counter-ions on ligand immobilization and pore structure

    Science.gov (United States)

    Riccardi, Enrico; Wang, Jee-Ching; Liapis, Athanasios I.

    2014-02-01

    Molecular dynamics modeling and simulations are employed to study the effects of counter-ions on the dynamic spatial density distribution and total loading of immobilized ligands as well as on the pore structure of the resultant ion exchange chromatography adsorbent media. The results show that the porous adsorbent media formed by polymeric chain molecules involve transport mechanisms and steric resistances which cause the charged ligands and counter-ions not to follow stoichiometric distributions so that (i) a gradient in the local nonelectroneutrality occurs, (ii) non-uniform spatial density distributions of immobilized ligands and counter-ions are formed, and (iii) clouds of counter-ions outside the porous structure could be formed. The magnitude of these counter-ion effects depends on several characteristics associated with the size, structure, and valence of the counter-ions. Small spherical counter-ions with large valence encounter the least resistance to enter a porous structure and their effects result in the formation of small gradients in the local nonelectroneutrality, higher ligand loadings, and more uniform spatial density distributions of immobilized ligands, while the formation of exterior counter-ion clouds by these types of counter-ions is minimized. Counter-ions with lower valence charges, significantly larger sizes, and elongated shapes, encounter substantially greater steric resistances in entering a porous structure and lead to the formation of larger gradients in the local nonelectroneutrality, lower ligand loadings, and less uniform spatial density distributions of immobilized ligands, as well as substantial in size exterior counter-ion clouds. The effects of lower counter-ion valence on pore structure, local nonelectroneutrality, spatial ligand density distribution, and exterior counter-ion cloud formation are further enhanced by the increased size and structure of the counter-ion. Thus, the design, construction, and functionality of

  8. Simulations of counterions at charged plates.

    Science.gov (United States)

    Moreira, A G; Netz, R R

    2002-05-01

    Using Monte Carlo simulations, we study the counterion distribution close to planar charged walls in two geometries: i) when only one charged wall is present and the counterions are confined to one half-space, and ii) when the counterions are confined between two equally charged walls. In both cases the surface charge is smeared out and the dielectric constant is the same everywhere. We obtain the counterion density profile and compare it with both the Poisson-Boltzmann theory (asymptotically exact in the limit of weak coupling, i.e. low surface charge, high temperature and low counterion valence) and the strong-coupling theory (valid in the opposite limit of high surface charge, low temperature and high counterion valence) and with previously calculated correction terms to both theories for different values of the coupling parameter, thereby establishing the domain of validity of the asymptotic limits. Gaussian corrections to the leading Poisson-Boltzmann behavior (obtained via a systematic loop expansion) in general perform quite poorly: At coupling strengths low enough so that the Gaussian (or one-loop) correction does describe the numerical deviations from the Poisson-Boltzmann result correctly, the leading Poisson-Boltzmann term by itself matches the data within high accuracy. This reflects the slow convergence of the loop expansion. For a single charged plane, the counterion pair correlation function indicates a behavioral change from a three-dimensional, weakly correlated counterion distribution (at low coupling) to a two-dimensional, strongly correlated counterion distribution (at high coupling), which is paralleled by the specific-heat capacity which displays a rounded hump at intermediate coupling strengths. For the case of counterions confined between two equally charged walls, we analyze the inter-wall pressure and establish the complete phase diagram, featuring attraction between the walls for large enough coupling strength and at intermediate wall

  9. Counterion distribution surrounding spherical nucleic acid-Au nanoparticle conjugates probed by small-angle x-ray scattering.

    Science.gov (United States)

    Kewalramani, Sumit; Zwanikken, Jos W; Macfarlane, Robert J; Leung, Cheuk-Yui; Olvera de la Cruz, Monica; Mirkin, Chad A; Bedzyk, Michael J

    2013-12-23

    The radial distribution of monovalent cations surrounding spherical nucleic acid-Au nanoparticle conjugates (SNA-AuNPs) is determined by in situ small-angle x-ray scattering (SAXS) and classical density functional theory (DFT) calculations. Small differences in SAXS intensity profiles from SNA-AuNPs dispersed in a series of solutions containing different monovalent ions (Na(+), K(+), Rb(+), or Cs(+)) are measured. Using the "heavy ion replacement" SAXS (HIRSAXS) approach, we extract the cation-distribution-dependent contribution to the SAXS intensity and show that it agrees with DFT predictions. The experiment-theory comparisons reveal the radial distribution of cations as well as the conformation of the DNA in the SNA shell. The analysis shows an enhancement to the average cation concentration in the SNA shell that can be up to 15-fold, depending on the bulk solution ionic concentration. The study demonstrates the feasibility of HIRSAXS in probing the distribution of monovalent cations surrounding nanoparticles with an electron dense core (e.g., metals).

  10. Non-mean-field screening by multivalent counterions

    Energy Technology Data Exchange (ETDEWEB)

    Loth, M S; Shklovskii, B I, E-mail: loth@physics.umn.ed [Department of Physics, University of Minnesota, Minneapolis, MN 55455 (United States)

    2009-10-21

    Screening of a strongly charged macroion by its multivalent counterions cannot be described in the framework of a mean-field Poisson-Boltzmann (PB) theory because multivalent counterions form a strongly correlated liquid (SCL) on the surface of the macroion. It was predicted that a distant counterion polarizes the SCL as if it were a metallic surface and creates an electrostatic image. The attractive potential energy of the image is the reason why the charge density of counterions decreases faster with distance from the charged surface than in PB theory. Using the Monte Carlo method to find the equilibrium distribution of counterions around the macroion, we confirm the existence of the image potential energy. It is also shown that, due to the negative screening length of the SCL, -2xi, the effective metallic surface is actually above the SCL by |xi|.

  11. The role of multipoles in counterion-mediated interactions between charged surfaces: strong and weak coupling

    Energy Technology Data Exchange (ETDEWEB)

    Kanduc, M; Podgornik, R [Department of Theoretical Physics, J Stefan Institute, SI-1000 Ljubljana (Slovenia); Naji, A [Department of Physics, Department of Chemistry and Biochemistry, Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States); Jho, Y S; Pincus, P A [Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States)

    2009-10-21

    We present general arguments for the importance, or lack thereof, of structure in the charge distribution of counterions for counterion-mediated interactions between bounding symmetrically charged surfaces. We show that on the mean field or weak coupling level, the charge quadrupole contributes the lowest order modification to the contact value theorem and thus to the intersurface electrostatic interactions. The image effects are non-existent on the mean field level even with multipoles. On the strong coupling level the quadrupoles and higher order multipoles contribute additional terms to the interaction free energy only in the presence of dielectric inhomogeneities. Without them, the monopole is the only multipole that contributes to the strong coupling electrostatics. We explore the consequences of these statements in all their generality.

  12. Salen complexes with dianionic counterions

    Energy Technology Data Exchange (ETDEWEB)

    Job, Gabriel E.; Farmer, Jay J.; Cherian, Anna E.

    2016-08-02

    The present invention describes metal salen complexes having dianionic counterions. Such complexes can be readily precipitated and provide an economical method for the purification and isolation of the complexes, and are useful to prepare novel polymer compositions.

  13. Preparation of counterion stabilized concentrated silver sols.

    Science.gov (United States)

    LaPlante, Sylas; Halaciuga, Ionel; Goia, Dan V

    2011-07-01

    A strategy for obtaining stable concentrated silver dispersions without dedicated stabilizing agents is presented. This approach consists of rapidly mixing aqueous solutions of silver salicylate and ascorbic acid. By using salicylate as Ag(+) counterion, it is possible to prepare stable sols with metal concentrations up to two orders of magnitude higher than with silver nitrate. The stabilizing effect of the counterion is the result of a decreased ionic strength due to salicylate protonation and its adsorption on the surface of silver. Both effects increase the range of the electrostatic repulsive forces by expanding the electrical double layer. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Dressed counterions: Polyvalent and monovalent ions at charged dielectric interfaces

    Science.gov (United States)

    Kanduč, Matej; Naji, Ali; Forsman, Jan; Podgornik, Rudolf

    2011-07-01

    We investigate the ion distribution and overcharging at charged interfaces with dielectric inhomogeneities in the presence of asymmetric electrolytes containing polyvalent and monovalent ions. We formulate an effective “dressed counterion” approach by integrating out the monovalent salt degrees of freedom and show that it agrees with results of explicit Monte Carlo simulations. We then apply the dressed counterion approach within the framework of the generalized strong-coupling theory, valid for polyvalent ions at low concentrations, which enables an analytical description for salt effects as well as dielectric inhomogeneities in the limit of strong Coulomb interactions. Limitations and applicability of this theory are examined by comparing the results with simulations.

  15. Counterions release from electrostatic complexes of polyelectrolytes and proteins of opposite charge : a direct measurement

    CERN Document Server

    Gummel, Jérémie; Boué, François

    2009-01-01

    Though often considered as one of the main driving process of the complexation of species of opposite charges, the release of counterions has never been experimentally directly measured on polyelectrolyte/proteins complexes. We present here the first structural determination of such a release by Small Angle Neutron Scattering in complexes made of lysozyme, a positively charged protein and of PSS, a negatively charged polyelectrolyte. Both components have the same neutron density length, so their scattering can be switched off simultaneously in an appropriate "matching" solvent; this enables determination of the spatial distribution of the single counterions within the complexes. The counterions (including the one subjected to Manning condensation) are expelled from the cores where the species are at electrostatic stoichiometry.

  16. Counterion influence on chemical shifts in strychnine salts

    Energy Technology Data Exchange (ETDEWEB)

    Metaxas, Athena E.; Cort, John R.

    2013-05-01

    The highly toxic plant alkaloid strychnine is often isolated in the form of the anion salt of its protonated tertiary amine. Here we characterize the relative influence of different counterions on 1H and 13C chemical shifts in several strychnine salts in D2O, methanol-d4 (CD3OD) and chloroform-d (CDCl3) solvents. In organic solvents, but not in water, substantial variation in chemical shifts of protons near the tertiary amine was observed among different salts. These secondary shifts reveal differences in the way each anion influences electronic structure within the protonated amine. The distributions of secondary shifts allow salts to be easily distinguished from each other as well as from the free base form. The observed effects are much greater in organic solvents than in water. Slight concentration-dependence in chemical shifts of some protons near the amine was observed for two salts in CDCl3, but this effect is small compared to the influence of the counterion. Distinct chemical shifts in different salt forms of the same compound may be useful as chemical forensic signatures for source attribution and sample matching of alkaloids such as strychnine and possibly other organic acid and base salts.

  17. Counterion influence on chemical shifts in strychnine salts.

    Science.gov (United States)

    Metaxas, Athena E; Cort, John R

    2013-05-01

    The highly toxic plant alkaloid strychnine is often isolated in the form of the anion salt of its protonated tertiary amine. Here, we characterize the relative influence of different counterions on (1)H and (13)C chemical shifts in several strychnine salts in D2O, methanol-d4 (CD3OD), and chloroform-d (CDCl3) solvents. In organic solvents but not in water, substantial variation in chemical shifts of protons near the tertiary amine was observed among different salts. These secondary shifts reveal differences in the way each anion influences electronic structure within the protonated amine. The distributions of secondary shifts allow salts to be easily distinguished from each other as well as from the free base form. Slight concentration dependence in chemical shifts of some protons near the amine was observed for two salts in CDCl3, but this effect is small compared with the influence of the counterion. Distinct chemical shifts in different salt forms of the same compound may be useful as chemical forensic signatures for source attribution and sample matching of alkaloids such as strychnine and possibly other organic acid and base salts. Copyright © 2013 John Wiley & Sons, Ltd.

  18. Specific interactions versus counterion condensation. 1. Nongelling ions/polyuronate systems.

    Science.gov (United States)

    Donati, Ivan; Cesàro, Attilio; Paoletti, Sergio

    2006-01-01

    The characteristics of the interaction between nongelling divalent cations (typically Mg(2+)) and polyuronates have been explored by means of isothermal calorimetry. In particular, three polyuronates mimicking separately guluronan (polyguluronate, polyG), mannuronan (polymannuronate, polyM), and polyalternating (polyMG), the three block-components of natural alginate samples, have been treated with divalent ions, and the enthalpy of mixing was determined for different values of the [M(2+)]/[Polym](rep.unit) ratio. Despite the absence of a site-specific chemical bonding between the two, as confirmed by circular dichroism spectroscopy, a substantial deviation of the experimental enthalpy of mixing from the theoretical behavior, as predicted by the classical counterion condensation (CC) theory, was observed. Such deviation has been interpreted in terms of a "generic" nonbonding affinity of the condensed divalent counterion for the polyelectrolytes. The mathematical formalism of the CC theory was extended to include a contribution to the (reduced) free energy and enthalpy arising from the counterion affinity, g(aff,0) and h(aff,0), and allowed the parametrical calculation of the fraction of divalent counterions condensed as function of the reduced thermodynamic quantity g(aff,0). A best fit procedure of the experimental enthalpy of mixing allowed the g(aff,0) and h(aff,0) pair to be estimated for each of the different polyuronates considered, revealing differences in the three samples. In qualitative terms, the results obtained seem to suggest a notable contribution of the desolvation process (i.e., release of structured water as a consequence of the interaction between the divalent counterion and the uronate group) to the enthalpy of affinity for polyM which is counterbalanced and overcome by an ion pairing term (i.e., partial formation of ion-ion and/or ion-dipole bonds) for polyG and polyMG, respectively.

  19. Counterion-mediated pattern formation in membranes containing anionic lipids.

    Science.gov (United States)

    Slochower, David R; Wang, Yu-Hsiu; Tourdot, Richard W; Radhakrishnan, Ravi; Janmey, Paul A

    2014-06-01

    Most lipid components of cell membranes are either neutral, like cholesterol, or zwitterionic, like phosphatidylcholine and sphingomyelin. Very few lipids, such as sphingosine, are cationic at physiological pH. These generally interact only transiently with the lipid bilayer, and their synthetic analogs are often designed to destabilize the membrane for drug or DNA delivery. However, anionic lipids are common in both eukaryotic and prokaryotic cell membranes. The net charge per anionic phospholipid ranges from -1 for the most abundant anionic lipids such as phosphatidylserine, to near -7 for phosphatidylinositol 3,4,5 trisphosphate, although the effective charge depends on many environmental factors. Anionic phospholipids and other negatively charged lipids such as lipopolysaccharides are not randomly distributed in the lipid bilayer, but are highly restricted to specific leaflets of the bilayer and to regions near transmembrane proteins or other organized structures within the plane of the membrane. This review highlights some recent evidence that counterions, in the form of monovalent or divalent metal ions, polyamines, or cationic protein domains, have a large influence on the lateral distribution of anionic lipids within the membrane, and that lateral demixing of anionic lipids has effects on membrane curvature and protein function that are important for biological control. Copyright © 2014. Published by Elsevier B.V.

  20. Aggregation number-based degrees of counterion dissociation in sodium n-alkyl sulfate micelles.

    Science.gov (United States)

    Lebedeva, Nataly V; Shahine, Antoine; Bales, Barney L

    2005-10-27

    Values of the degree of counterion dissociation, alpha, for sodium n-alkyl sulfate micelles, denoted by SN(c)S, where N(c) is the number of carbon atoms in the alkyl chain, are defined by asserting that the aggregation number, N, is dependent only on the concentration, C(aq), of counterions in the aqueous pseudophase. By using different combinations of surfactant and added salt concentrations to yield the same value of N, alpha can be determined, independent of the experimental method. Electron paramagnetic resonance measurements of the hyperfine spacings of two nitroxide spin probes, 16- and 5-doxylstearic acid methyl ester (16DSE and 5DSE, respectively), are employed to determine whether micelles from two samples have the same value of N to high precision. The EPR spectra are different for the two spin probes, but the values of alpha are the same, within experimental error, as they must be. In agreement with recent work on S12S and with prevailing thought in the literature, values of alpha are constant as a function of N. This implies that the value of alpha is constant whether the surfactant or added electrolyte concentrations are varied. Interestingly, alpha varies with chain length as follows: N(c) = 8, alpha = 0.42 +/- 0.03; N(c) = 9, alpha = 0.41 +/- 0.03; N(c) = 10, alpha = 0.35 +/- 0.02; N(c) = 11, alpha = 0.30 +/- 0.02 at 25 degrees C and N(c) = 13, alpha = 0.22 +/- 0.02; and N(c) = 14, alpha = 0.19 +/- 0.01 at 40 degrees C. A simple electrostatic theoretical description, based on the nonlinear Poisson-Boltzmann equation for the ion distribution around a charged sphere, was compared with the experimental results. The theory predicts values of alpha that are in reasonable agreement with experiment, nicely predicting the decrease of alpha as N(c) increases. However, the theory also predicts that, for a given value of N(c), alpha decreases as N increases. Moreover, this decrease is predicted to be different if N is increased by adding salt or by increasing

  1. Role of Counterions in Controlling the Properties of Ultrasonically Generated Chitosan-Stabilized Oil-in-Water Emulsions.

    Science.gov (United States)

    Colombo, Enrico; Cavalieri, Francesca; Ashokkumar, Muthupandian

    2015-06-17

    An oil-in-water emulsion was ultrasonically prepared in aqueous chitosan solutions containing different counterions. Tetradecane was used as the oil phase in order to mimic nonpolar substances used in food processes. Various acids were used to dissolve chitosan, and we found that conjugate bases of the acids used, which act as counterions to neutralize the positive charges of ammonium ions present in the chitosan backbone, played a significant role in controlling the size, size distribution, and stability of chitosan-encapsulated tedradecane emulsion droplets (microspheres). The counterion effect is also found to be strongly dependent upon tetradecane (TD)/chitosan (CS) ratio and ultrasonic power. Key observations are: (i) for a given TD/CS ratio, the size and size distribution decrease when the acid is varied from nitric acid to benzenesulfonic acid at high TD/CS ratio, and the effect becomes less significant at low TD/CS ratio; (ii) for a given acid, the size and size distribution increase with an increase in TD/CS ratio; and (iii) at low TD/CS ratio the size and size distribution are significantly influenced by the viscosity of the system. A possible mechanism for the observed counterion effect is proposed. The role of counterions, solution viscosity, and ultrasonic power in controlling the physical and functional properties of ultrasonically generated chitosan-stabilized tetradecane microspheres is discussed in detail. The key new finding of this study is that it is possible to form stable emulsions without the addition of external emulsifiers and stabilizers, but only using chitosan with different acids to dissolve chitosan. This strategy could be used in the generation of stable food emulsions.

  2. Protein Adsorption into Mesopores: A Combination of Electrostatic Interaction, Counterion Release and van der Waals Forces

    CERN Document Server

    Moerz, Sebastian T

    2015-01-01

    Bovine heart cytochrome c has been immobilized into the mesoporous silica host material SBA-15 in both its native folded and urea-unfolded state. The comparison of the two folding states' behavior casts doubt on the commonly used explanation of cytochrome c adsorption, i.e. the electrostatic interaction model. A detailed investigation of the protein binding as a function of pH and ionic strength of the buffer solution reveals the complex nature of the protein-silica interaction. Electrostatic interaction, van der Waals forces and entropic contributions by counterion release each contribute to adsorption on the silica pore walls.

  3. PKA distributions: Contributions from transmutation products and from radioactive decay

    Directory of Open Access Journals (Sweden)

    M.R. Gilbert

    2016-12-01

    Full Text Available The neutrons generated in fusion plasmas interact with materials via nuclear reactions. The resulting transmutations and atomic displacements have life-limiting consequences for fusion reactor components. A detailed understanding of the production, evolution and material consequences of the damage created by cascades of atomic displacements requires, as a vital primary input, a complete description of the energy-spectrum of initial (prompt atomic displacement events (the primary knock on atoms or PKAs produced by direct neutron nuclear interactions. There is also the possibility that the radionuclides produced under transmutation will create further PKAs as they decay, and so the rate of these must also be quantified. This paper presents the latest results from the analysis of PKA spectra under neutron irradiation, focussing particularly on the variation in PKA distributions due to changes in composition under transmutation, but also on the PKA contributions from radioactive decay of materials that become activated under irradiation.

  4. Characterizing groundwater contribution to lowland streams using Travel Time Distribution

    Science.gov (United States)

    Petrus Kaandorp, Vincentius; Gerardus Bernardus de Louw, Petrus; Kuijper, Martina Johanna Maria; Broers, Hans Peter

    2015-04-01

    approach in which the groundwater contribution is specified based on travel times. The travel time distribution of groundwater input was calculated for several bigger and smaller streams in the Regge and Dinkel lowland catchment in The Netherlands using a coupled groundwater-surface water model and linked to physical catchment characteristics. More knowledge about the groundwater contribution provides water managers with insights which would help improve the ecological status of streams.

  5. Counterion condensation in ionic micelles as studied by a combined use of SANS and SAXS

    Indian Academy of Sciences (India)

    V K Aswal; P S Goyal; H Amenitsch; S Bernstorff

    2004-08-01

    We report a combined use of small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS) to the study of counterion condensation in ionic micelles. Small-angle neutron and X-ray scattering measurements have been carried out on two surfactants cetyltrimethylammonium bromide (CTABr) and cetyltrimethylammonium chloride (CTACl), which are similar but having different counterions. SANS measurements show that CTABr surfactant forms much larger micelles than CTACl. This is explained in terms of higher condensation of Br0 counterions than Cl- counterions. SAXS data on these systems suggest that the Br- counterions are condensed around the micelles over smaller thickness than those of Cl- counterions.

  6. NMR-based conformation and dynamics of a tetrasaccharide-repeating sulfated fucan substituted by different counterions.

    Science.gov (United States)

    Soares, Paulo A G; Queiroz, Ismael N L; Santos, Gustavo R C; Mourão, Paulo A S; Pomin, Vitor H

    2016-11-01

    The sulfated fucan from the sea urchin Lytechinus variegatus is composed of the repetitive sequence [-3)-α-l-Fucp-4( OSO3-)-(1-3)-α-l-Fucp-2,4-di( OSO3-)-(1-3)-α-l-Fucp-2( OSO3-)-(1-3)-α-l-Fucp-2( OSO3-)-(1-]n . Conformation (of rings and chains) and dynamics of this tetrasaccharide-repeating sulfated fucan substituted by Na(+) , Ca(2+) , and Li(+) as counterions have been examined through experiments of liquid-state nuclear magnetic resonance spectroscopy. Scalar coupling and nuclear Overhauser effect (NOE)-based data have confirmed that all composing units occur as (1) C4 chair conformer regardless of the cation type, unit position within the repeating sequence, and sulfation type. Chain conformation determined by NOE signal pattern assisted by molecular modeling for a theoretical octasaccharide has shown a similar linear 3D structure for the three differently substituted forms. Data derived from spin-relaxation measurements have indicated a contribution of counterion type to dynamics. The calcium-based preparation has shown the highest mobility while the sodiated one showed the lowest mobility. The set of results from this work suggests that counterion type can affect the physicochemical properties of the structurally well-defined sulfated fucan. The counterion effect seems to impact more on the structural mobility than on average conformation of the studied sulfated glycan in solution.

  7. Competitive adsorption and ordered packing of counterions near highly charged surfaces: From mean-field theory to Monte Carlo simulations.

    Science.gov (United States)

    Wen, Jiayi; Zhou, Shenggao; Xu, Zhenli; Li, Bo

    2012-04-01

    Competitive adsorption of counterions of multiple species to charged surfaces is studied by a size-effect-included mean-field theory and Monte Carlo (MC) simulations. The mean-field electrostatic free-energy functional of ionic concentrations, constrained by Poisson's equation, is numerically minimized by an augmented Lagrangian multiplier method. Unrestricted primitive models and canonical ensemble MC simulations with the Metropolis criterion are used to predict the ionic distributions around a charged surface. It is found that, for a low surface charge density, the adsorption of ions with a higher valence is preferable, agreeing with existing studies. For a highly charged surface, both the mean-field theory and the MC simulations demonstrate that the counterions bind tightly around the charged surface, resulting in a stratification of counterions of different species. The competition between mixed entropy and electrostatic energetics leads to a compromise that the ionic species with a higher valence-to-volume ratio has a larger probability to form the first layer of stratification. In particular, the MC simulations confirm the crucial role of ionic valence-to-volume ratios in the competitive adsorption to charged surfaces that had been previously predicted by the mean-field theory. The charge inversion for ionic systems with salt is predicted by the MC simulations but not by the mean-field theory. This work provides a better understanding of competitive adsorption of counterions to charged surfaces and calls for further studies on the ionic size effect with application to large-scale biomolecular modeling.

  8. Exploring the Counterion Atmosphere around DNA: What Can Be Learned from Molecular Dynamics Simulations?

    OpenAIRE

    Rueda, Manuel; Cubero, Elena; Laughton, Charles A.; Orozco, Modesto

    2004-01-01

    The counterion distribution around a DNA dodecamer (5′-CGCGAATTCGCG-3′) is analyzed using both standard and novel techniques based on state of the art molecular dynamics simulations. Specifically, we have explored the population of Na+ in the minor groove of DNA duplex, and whether or not a string of Na+ can replace the spine of hydration in the narrow AATT minor groove. The results suggest that the insertion of Na+ in the minor groove is a very rare event, but that when once the ion finds sp...

  9. Contributions of Determining the Forces Distribution in the Harmonic Drive

    Directory of Open Access Journals (Sweden)

    Sava Ianici

    2006-10-01

    Full Text Available The paper presents an original method for determining the forces distributions on the portant elements of the harmonic drives. This method is based on the thin wall shells theory anal on the rotating character of the distributed forces that work upon the flexible toothed wheel.

  10. Experimental evidence of counterion affinity in alginates: the case of nongelling ion Mg2+.

    Science.gov (United States)

    Donati, Ivan; Asaro, Fioretta; Paoletti, Sergio

    2009-10-01

    The present contribution aims at testing experimentally the theoretical model previously devised (Donati, I.; Cesaro, A.; Paoletti, S.; Biomacromolecules 2006, 7, 281-287) for the description of the interaction between alginate and nongelling Mg(2+) ions. The model, based on an extension of the counterion condensation theory, introduces a contribution of free energy of affinity, DeltaG(aff,0), which depends on the monomer composition of the polyuronate. In the present work, three different alginates separately mimicking the mannuronan (polyM), the guluronan (polyG), and the polyalternating (polyMG) components of alginate, together with a natural alginate isolated from Laminaria hyperborea ( L. hyperborea ), were examined. They were treated with Mg(2+) ions, and relative variations in scattered light intensity, isothermal calorimetry (DeltaH(mix)), specific viscosity, and (23)Na NMR longitudinal relaxation rates were monitored with respect to samples at the same ionic strength but containing only Na(+) ions. The fraction of condensed magnesium counterions was found to be strongly dependent on alginate composition, increasing along the series mannuronan < polyalternating approximately L. hyperborea < guluronan, thus in good agreement with the theoretical predictions.

  11. 26 CFR 1.704-4 - Distribution of contributed property.

    Science.gov (United States)

    2010-04-01

    ... capital and profits. A and B are wholly owned subsidiaries of the same affiliated group and continue to... owned through the partnership by members of the contributing affiliated group of which A is a member...

  12. Electromagnetic contribution to charge symmetry violation in parton distributions

    Directory of Open Access Journals (Sweden)

    X.G. Wang

    2016-02-01

    Full Text Available We report a calculation of the combined effect of photon radiation and quark mass differences on charge symmetry violation (CSV in the parton distribution functions of the nucleon. Following a recent suggestion of Martin and Ryskin, the initial photon distribution is calculated in terms of coherent radiation from the proton as a whole, while the effect of the quark mass difference is based on a recent lattice QCD simulation. The distributions are then evolved to a scale at which they can be compared with experiment by including both QCD and QED radiation. Overall, at a scale of 5 GeV2, the total CSV effect on the phenomenologically important difference between the d and u-quark distributions is some 20% larger than the value based on quark mass differences alone. In total these sources of CSV account for approximately 40% of the NuTeV anomaly.

  13. Molecular Dynamics Simulations Illuminate the Role of Counterion Condensation in the Electrophoretic Transport of Homogalacturonans.

    Science.gov (United States)

    Irani, Amir H; Owen, Jessie L; Mercadante, Davide; Williams, Martin A K

    2017-02-13

    Homogalacturonans (HGs) are polysaccharide copolymers of galacturonic acid and its methylesterified counterpart. The inter- and intramolecular distributions of the methylesterifed residues are vital behavior-determining characteristics of a sample's structure, and much experimental effort has been directed to their measurement. While many techniques are able to measure the sample-averaged degree of methylesterification (DM), the measurement of inter- and intramolecular charge distributions are challenging. Here, molecular dynamics (MD) simulations are used to calculate the electrophoretic mobilities of HGs that have different amounts and distributions of charges placed along the backbone. The simulations are shown to capture experimental results well, even for low-DM samples that possess high charge densities. In addition, they illuminate the role that local counterion condensation can play in the determination of the electrophoretic mobility of heterogeneous blocky polyelectrolytes that cannot be adequately described by a single chain-averaged charge spacing.

  14. The Geographic Distribution of Human Capital: Measurement of Contributing Mechanisms

    OpenAIRE

    2010-01-01

    This paper investigates how the geographic distribution of human capital evolves over time. With U.S. data, I decompose generation-to-generation changes in local human capital into three factors: the previous generation’s human capital, intergenerational transmission of skills from parents to their children, and migration of the children. I find evidence of regression to the mean of local skills at the state level and divergence at the commuting zone level. Labor market size, climate, local c...

  15. Dynamics of flexible counter-ions in conducting polyaniline a quasielastic neutron-scattering study

    CERN Document Server

    Bee, M; Djurado, D; Marque, D; Combet, J; Rannou, P; Dufour, B

    2002-01-01

    Conducting polyaniline protonated with sulphonic flexible counter-ions was investigated by quasielastic incoherent neutron scattering. In addition to their role in electrical properties, the flexible counter-ions also increase the elasticity of the samples. As in the case of more rigid counter-ions, polymer chains appear as very stiff objects whose dynamics is completely outside the investigated time scale. Conversely, the counter-ion dynamics was proved to be of major importance in charge transport since a dynamical transition is observed precisely in the temperature range where the electronic properties change from a metallic to a semiconducting regime. (orig.)

  16. Effects of concentration and temperature on the dynamic behavior of PAA-g-PEO aqueous solutions with different counterion species: a dielectric spectroscopy study.

    Science.gov (United States)

    Liu, Chunyan; Zhao, Kongshuang

    2012-01-19

    Dielectric properties of PAA-g-PEO-7% solutions with different counterions were measured as a function of concentration and temperature over a frequency range of 40 Hz to 110 MHz. After the contribution of electrode polarization effects was subtracted, the dielectric spectra of PAA-g-PEO-7% solutions showed three relaxation processes in the experimental frequency range, named low-, mid-, and high-frequency relaxation. The observed three relaxations were strictly analyzed by using the Cole-Cole relaxation function, and the dielectric parameters (dielectric increment Δε and the relaxation time τ) were obtained. The scaling relation of dielectric increment and relaxation time of high frequency with concentration C(p) were obtained and compared with the predictions of scaling theories. The information on the dynamics and microstructure of PAA-g-PEO-7% was obtained. Using different counterion species, the mid- and high-frequency relaxation mechanisms were attributed to the fluctuation of condensed counterions and free counterions, respectively, and the low-frequency relaxation was considered to be caused by the interface polarization of a complex formed by the hydrogen bonding between carboxylic group of PAA and ether oxygen on the side-chain PEO. In addition, by means of Eyring equation, the thermodynamic parameters, enthalpy change ΔH and entropy change ΔS, of the three relaxations were calculated from the relaxation time and discussed from the microscopic thermodynamical view.

  17. Mechanistic insights on cooperative asymmetric multicatalysis using chiral counterions.

    Science.gov (United States)

    Jindal, Garima; Sunoj, Raghavan B

    2014-08-15

    Cooperative multicatalytic methods are steadily gaining popularity in asymmetric catalysis. The use of chiral Brønsted acids such as phosphoric acids in conjunction with a range of transition metals has been proven to be effective in asymmetric synthesis. However, the lack of molecular-level understanding and the accompanying ambiguity on the role of the chiral species in stereoinduction continues to remain an unresolved puzzle. Herein, we intend to disclose some novel transition state models obtained through DFT(B3LYP and M06) computations for a quintessential reaction in this family, namely, palladium-catalyzed asymmetric Tsuji-Trost allylation of aldehydes. The aldehyde is activated as an enamine by the action of a secondary amine (organocatalysis), which then adds to an activated Pd-allylic species (transition metal catalysis) generated through the protonation of allyic alcohol by chiral BINOL-phosphoric acid (Brønsted acid catalysis). We aim to decipher the nature of chiral BINOL-phosphates and their role in creating a quaternary chiral carbon atom in this triple catalytic system. The study reports the first transition state model capable of rationalizing chiral counterion-induced enantioselectivity. It is found that the chiral phosphate acts as a counterion in the stereocontrolling event rather than the conventional ligand mode.

  18. A Generalized Model for Electrical Power Distribution Feeders’ Contributions to System Reliability Indices

    Directory of Open Access Journals (Sweden)

    Ganiyu A. Ajenikoko

    2014-01-01

    Full Text Available Reliability indices are parametric quantities used to assess the performance levels of electrical power distribution systems. In this work, a generalized quadratic model is developed for electrical power distribution system contributions to system reliability indices using Ikeja, Port-Harcourt, Kaduna and Kano distribution system feeders as case studies. The mean System Average Interruption Duration Index (SAIDI, System Average Interruption Frequency Index (SAIFI and Customer Average Interruption Duration Index (CAIDI contributions to system reliability indices for Ikeja, Port-Harcourt, Kaduna and Kano distribution systems were 0.0033, 0.0026, 0.0033 and 0.0018 respectively due to the fact that a prolonged period of interruptions was recorded on most of the feeders attached to Port-Harcourt and Kano distribution systems making them to be less reliable compared to Ikeja and Kaduna distribution systems. The generalized Quadratic model forms a basis for a good design, planning and maintenance of distribution systems at large.

  19. Distribution, origin and transformation of amino sugars sand bacterial contribution to estuarine particulate organic matter

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Bhosle, N.B.

    Amino sugars including bacterial biomarker muramic acid(Mur) were investigated in suspended particulate matter(SPM) to understand their distribution, origin, and biogeochemical cycling and the contribution of bacteria to particulate organic matter...

  20. Counterion-induced reversibly switchable transparency in smart windows.

    Science.gov (United States)

    Lee, Chang Hwan; Lim, Ho Sun; Kim, Jooyong; Cho, Jeong Ho

    2011-09-27

    Smart windows that can reversibly alternate between extreme optical characteristics via clicking counteranions of different hydration energies were developed on glass substrates through the facile spray-casting of poly[2-(methacryloyloxy)ethyltrimethylammonium chloride-co-3-(trimethoxysilyl)propyl methacrylate]. The optical transmittance was either 90.9% or 0% over the whole spectral range when alternately immersed in solutions containing thiocyanate (SCN(-)) or bis(trifluoromethane)sulfonimide (TFSI(-)) ions, respectively. The extreme optical transitions were attributed to formation of microporous structures via the molecular aggregation of polyelectrolyte chains bearing TFSI(-) ions in methanol. Because the smart windows were either highly transparent toward or completely blocking of incident light upon direct counterion exchange, this kind of nanotechnology may provide a new platform for efficiently conserving on energy usage in the interior of buildings.

  1. The contribution to distribution network fault levels from the connection of distributed generation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the findings of a study investigating the potential impact of distributed generation (DG) on the UK distribution network fault levels up to the year 2010, and examining ways of managing the fault levels so that they do not become a barrier to increased penetration of DG. The project focuses on the circumstances and scenarios that give rise to the fault levels. The background to the study is traced, and a technical review is presented covering the relationship between DG and fault levels, and the likely impact in the period to 2010. Options for managing increased fault levels, and fault level management and costs are outlined, and a case study is given. The measurement and calculation of fault level values are described along with constraints to DG penetration due to fault level limitations, characteristics of DG machines, and long term perspectives to 2020-2030.

  2. Self-assembly of lamellar lipid-DNA complexes simulated by explicit solvent counterion model.

    Science.gov (United States)

    Gao, Lianghui; Cao, Jun; Fang, Weihai

    2010-06-03

    The dissipative particle dynamics simulations with explicit solvent and counterions are used to mimic the self-assembly of lamellar cationic lipid-DNA (CL-DNA)complexes. We found that the formation of the complexes is associated with the releasing of 70% DNA counterions and 90% lipid counterions. The trapped DNA and CL charges together with their counterions inside the complex still keep the interior neutral, which stabilized the structure. Simulations in constant pressure ensemble following the self-assembly show that the DNA interaxial spacing as a function of the inversed CL concentrations 1/phi(c) is linear at low phi(c) and nonlinear at high phi(c). The attraction between the DNA and the CLs as well as the repulsion between the DNA strands impose stretching stress on the membrane so that the averaged area per lipid is dependent on the CL concentration, which in turn determines the behavior of the DNA spacing.

  3. Counterion effects on nano-confined metal–drug–DNA complexes

    Directory of Open Access Journals (Sweden)

    Nupur Biswas

    2016-01-01

    Full Text Available We have explored morphology of DNA molecules bound with Cu complexes of piroxicam (a non-steroidal anti-inflammatory drug molecules under one-dimensional confinement of thin films and have studied the effect of counterions present in a buffer. X-ray reflectivity at and away from the Cu K absorption edge and atomic force microscopy studies reveal that confinement segregates the drug molecules preferentially in a top layer of the DNA film, and counterions enhance this segregation.

  4. Protein adsorption to poly(ethylenimine)-modified Sepharose FF: V. Complicated effects of counterions.

    Science.gov (United States)

    Liu, Na; Yu, Linling; Sun, Yan

    2015-07-24

    In the previous studies on protein adsorption to poly(ethylenimine) (PEI)-grafted Sepharose FF resins, a critical ionic capacity (600mmol/L) of PEI-Sepharose resins was found for the adsorption of bovine serum albumin (BSA), above which both protein capacity and uptake rate increased drastically. In this work, the influence of counterions on the PEI-Sepharose resin with an ionic capacity of 683mmol/L (FF-PEI-L680) was investigated with sodium salts of SCN(-), Cl(-), HPO4(2-) and SO4(2-). Linear gradient elution, batch adsorption and breakthrough experiments showed that counterion preference, effective pore diffusion coefficient (De) and dynamic binding capacity (DBC) values increased in the order of SCN(-), Cl(-), HPO4(2-) and SO4(2-), while static adsorption capacity decreased in this order. It is considered that higher counterion preference of the ion exchange groups resulted in lower protein binding strength and adsorption capacity, while the De value increased due to the enhanced "chain delivery" effect (a kind of surface diffusion). Besides, the DBC value was mainly dependent on De value. In particular, SO4(2-) was the most favorable counterion for the PEI-Sepharose resin, which gave rise to the highest De value (De/D0=1.17, D0 is protein diffusivity in free solution) and DBC value (118mg/mL at a residence time of 2min). Moreover, the effects of counterions on BSA adsorption to DEAE Sepharose FF and Q Sepharose FF, which were non-grafted resins, were also studied for comparisons. It was found that the counterion preferences of the two non-grafted resins were different from each other and also different from that of FF-PEI-L680. The different counterion preferences were attributed to the differences in the ion-exchange ligand chemistries. In addition, the De values for DEAE Sepharose FF and Q Sepharose FF kept unchanged. The low counterion sensitivity of De values could be interpreted as the lack of "chain delivery" effect for the non-grafted resins. The

  5. Determination of inorganic pharmaceutical counterions using hydrophilic interaction chromatography coupled with a Corona CAD detector.

    Science.gov (United States)

    Huang, Z; Richards, M A; Zha, Y; Francis, R; Lozano, R; Ruan, J

    2009-12-05

    A simple generic approach was investigated for the determination of inorganic pharmaceutical counterions in drug substances using conventional high performance liquid chromatographic (HPLC) instruments. An intuitive approach combined Corona charged aerosol detection (CAD) with a polymer-based zwitterionic stationary phase in the hydrophilic interaction chromatography (HILIC) mode. Two generic methods based on this HILIC/CAD technique were developed to quantitate counterions such as Cl-, Br-, SO(4)(2-), K+, Ca2+ and Mg2+ in different pharmaceutical compounds. The development and capability of this HILIC/CAD technique analysis were examined. HILIC/CAD was compared to ion chromatography (IC), the most commonly used methodology for pharmaceutical counterion analysis. HILIC/CAD was found to have significant advantages in terms of: (1) being able to quantitate both anions and cations simultaneously without a need to change column/eluent or detection mode; (2) imposing much less restriction on the allowable organic percentage of the eluents than IC, and therefore being more appropriate for analysis of counterions of poorly water-soluble drugs; (3) requiring minimal training of the operating analysts. The precision and accuracy of counterion analysis using HILIC/CAD was not compromised. A typical precision of <2.0% was observed for all tested inorganic counterions; the determinations were within 2.0% relative to the theoretical counterion amount in the drug substance. Additionally, better accuracy was shown for Cl- in several drug substances as compared to IC. The main drawback of HILIC/CAD is its unsuitability for many of the current silica-based HILIC columns, because slight dissolution of silica leads to high baseline noise in the CAD detector. As a result of the universal detection characteristics of Corona CAD and the unique separation capabilities of a zwitterionic stationary phase, an intuitive and robust HPLC method was developed for the generic determination of

  6. Dielectric relaxation spectroscopy shows a sparingly hydrated interface and low counterion mobility in triflate micelles.

    Science.gov (United States)

    Lima, Filipe S; Chaimovich, Hernan; Cuccovia, Iolanda M; Buchner, Richard

    2013-08-13

    The properties of ionic micelles are affected by the nature of the counterion. Specific ion effects can be dramatic, inducing even shape and phase changes in micellar solutions, transitions apparently related to micellar hydration and counterion binding at the micellar interface. Thus, determining the hydration and dynamics of ions in micellar systems capable of undergoing such transitions is a crucial step in understanding shape and phase changes. For cationic micelles, such transitions are common with large organic anions as counterions. Interestingly, however, phase separation also occurs for dodecyltrimethylammonium triflate (DTATf) micelles in the presence of sodium triflate (NaTf). Specific ion effects for micellar solutions of dodecyltrimethylammonium chloride (DTAC), bromide (DTAB), methanesulfonate (DTAMs), and triflate (DTATf) were studied with dielectric relaxation spectroscopy (DRS), a technique capable of monitoring hydration and counterion dynamics of micellar aggregates. In comparison to DTAB, DTAC, and DTAMs, DTATf micelles were found to be considerably less hydrated and showed reduced counterion mobility at the micellar interface. The obtained DTATf and DTAMs data support the reported central role of the anion's -CF3 moiety with respect to the properties of DTATf micelles. The reduced hydration observed for DTATf micelles was rationalized in terms of the higher packing of this surfactant compared to that of other DTA-based systems. The decreased mobility of Tf(-) anions condensed at the DTATf interface strongly suggests the insertion of Tf(-) in the micellar interface, which is apparently driven by the strong hydrophobicity of -CF3.

  7. [Gene geography of Chile: regional distribution of American, European and African genetic contributions].

    Science.gov (United States)

    Fuentes, Macarena; Pulgar, Iván; Gallo, Carla; Bortolini, María-Cátira; Canizales-Quinteros, Samuel; Bedoya, Gabriel; González-José, Rolando; Ruiz-Linares, Andrés; Rothhammer, Francisco

    2014-03-01

    The geographical distribution of genes plays a key role in genetic epidemiology. The Chilean population has three major stem groups (Native American, European and African). To estimate the regional rate of American, European and African admixture of the Chilean population. Forty single nucleotide polymorphisms (SNP´s) which exhibit substantially different frequencies between Amerindian populations (ancestry-informative markers or AIM´s), were genotyped in a sample of 923 Chilean participants to estimate individual genetic ancestry. The American, European and African individual average admixture estimates for the 15 Chilean Regions were relatively homogeneous and not statistically different. However, higher American components were found in northern and southern Chile and higher European components were found in central Chile. A negative correlation between African admixture and latitude was observed. On the average, American and European genetic contributions were similar and significantly higher than the African contribution. Weighted mean American, European and African genetic contributions of 44.34% ± 3 9%, 51.85% ± 5.44% and 3.81% ± 0.45%, were estimated. Fifty two percent of subjects harbor African genes. Individuals with Aymara and Mapuche surnames have an American admixture of 58.64% and 68.33%, respectively. Half of the Chilean population harbors African genes. Participants with Aymara and Mapuche surnames had a higher American genetic contribution than the general Chilean population. These results confirm the usefulness of surnames as a first approximation to determine genetic ancestry.

  8. STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles.

    Science.gov (United States)

    Kudernac, Tibor; Shabelina, Natalia; Mamdouh, Wael; Höger, Sigurd; De Feyter, Steven

    2011-01-01

    Despite their importance in self-assembly processes, the influence of charged counterions on the geometry of self-assembled organic monolayers and their direct localisation within the monolayers has been given little attention. Recently, various examples of self-assembled monolayers composed of charged molecules on surfaces have been reported, but no effort has been made to prove the presence of counterions within the monolayer. Here we show that visualisation and exact localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM). The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid-solid interface. Furthermore, preferential adsorption was observed for the uncharged analogue of the macrocycle on a surface.

  9. Engineering the Structure and Properties of DNA-Nanoparticle Superstructures Using Polyvalent Counterions.

    Science.gov (United States)

    Chou, Leo Y T; Song, Fayi; Chan, Warren C W

    2016-04-06

    DNA assembly of nanoparticles is a powerful approach to control their properties and prototype new materials. However, the structure and properties of DNA-assembled nanoparticles are labile and sensitive to interactions with counterions, which vary with processing and application environment. Here we show that substituting polyamines in place of elemental counterions significantly enhanced the structural rigidity and plasmonic properties of DNA-assembled metal nanoparticles. These effects arose from the ability of polyamines to condense DNA and cross-link DNA-coated nanoparticles. We further used polyamine wrapped DNA nanostructures as structural templates to seed the growth of polymer multilayers via layer-by-layer assembly, and controlled the degree of DNA condensation, plasmon coupling efficiency, and material responsiveness to environmental stimuli by varying polyelectrolyte composition. These results highlight counterion engineering as a versatile strategy to tailor the properties of DNA-nanoparticle assemblies for various applications, and should be applicable to other classes of DNA nanostructures.

  10. Counterion exchange to achieve reversibly switchable hydrophobicity and oleophobicity on fabrics.

    Science.gov (United States)

    Yang, Jin; Zhang, Zhaozhu; Men, Xuehu; Xu, Xianghui; Zhu, Xiaotao; Zhou, Xiaoyan

    2011-06-21

    We describe a simple layer-by-layer (LbL) technology and counterion exchange procedure to tune the liquid wettability of commercially available cotton fabrics. A polyelectrolyte multilayer is deposited on the fabric surface by the LbL technology, and counterion exchange is used to control the surface composition and thereby to modulate the solid surface energy. The tunability of the solid surface energy, along with the inherent re-entrant texture of the cotton fabric, results in simultaneously switchable wettability between a nonwetting state and a fully wetted state for water and hexadecane. This switchable hydrophobicity and oleophobicity can be explained within a robustness factor, which is a quantitative criterion for the transition between the two states. The counterion exchange can be confirmed by X-ray photoelectron spectroscopy analysis.

  11. Differential dose contributions on total dose distribution of (125)I brachytherapy source.

    Science.gov (United States)

    Camgöz, B; Yeğin, G; Kumru, M N

    2010-01-01

    This work provides an improvement of the approach using Monte Carlo simulation for the Amersham Model 6711 (125)I brachytherapy seed source, which is well known by many theoretical and experimental studies. The source which has simple geometry was researched with respect to criteria of AAPM Tg-43 Report. The approach offered by this study involves determination of differential dose contributions that come from virtual partitions of a massive radioactive element of the studied source to a total dose at analytical calculation point. Some brachytherapy seeds contain multi-radioactive elements so the dose at any point is a total of separate doses from each element. It is momentous to know well the angular and radial dose distributions around the source that is located in cancerous tissue for clinical treatments. Interior geometry of a source is effective on dose characteristics of a distribution. Dose information of inner geometrical structure of a brachytherapy source cannot be acquired by experimental methods because of limits of physical material and geometry in the healthy tissue, so Monte Carlo simulation is a required approach of the study. EGSnrc Monte Carlo simulation software was used. In the design of a simulation, the radioactive source was divided into 10 rings, partitioned but not separate from each other. All differential sources were simulated for dose calculation, and the shape of dose distribution was determined comparatively distribution of a single-complete source. In this work anisotropy function was examined also mathematically.

  12. Effect of Variant Counterions on Stability and Particle Size of Silica Sol

    Institute of Scientific and Technical Information of China (English)

    PAN, Ming-Chu; YANG, Yu-Xiang; YING, Hai-Ping; JIA, Xiang-Chen; CHEN, Ya-Ru; TANG, Yue

    2007-01-01

    The effects of variant counterions with ionic strength of 0.05, 0.10, 0.20 and 0.25 mol·kg-1 on the stability and particle size of silica sols have been studied using the traditional methods of Ubbelohde viscosity measurement, TEM and titration respectively, finding that the stability and particle size of the silica sols are all concerned with the acidic, positively electric properties and the sizes of the counterions, as well as the attraction between the counteri ons and surface silicon hydroxyl groups of the silica sols. The small positively charged counterions lead to the de crease in particle sizes, making the silica sol the most stable. But the larger weakly acidic counterions can restrict the particle sizes of the silica sols and easily make the sols coagulate. It was also found that there existed a linear relationship between log r and log η, which has not ever been reported. The effect of temperature on the stability and particle sizes was also discussed.

  13. Counter-ion complexes for enhanced drug loading in nanocarriers: Proof-of-concept and beyond.

    Science.gov (United States)

    Günday Türeli, Nazende; Türeli, Akif E; Schneider, Marc

    2016-09-25

    Enhanced drug loading is an important prerequisite of nanomedicines, to reach administration dose while reducing the amount of excipient. Considering biocompatible and biodegradable polymers such as PLGA, pH dependent solubility characteristics along with limited organic solvent solubility of the drug hampers nanoparticle (NP) preparation. To improve loading of such molecules, a method based on using counter ions for complex formation is proposed. Formed complex alters the intrinsic solubility of active substance via electrostatic interaction without chemical modification. A proof-of-concept study was conducted with sodium dodecyl sulfate as counter-ion to fluoroquinolone antibiotic ciprofloxacin. Complex formation resulted in suppressed pH dependent solubility over pH 1.2-9.0 and an additional -80 fold increase in organic solubility was achieved. In consequence, NPs prepared by microjet reactor technology have shown enhanced drug loading efficiencies (-78%) and drug loading of 14%. Moreover, the counter-ion concept was also demonstrated with another class of antibiotics, water soluble aminoglycosides gentamycin and tobramycin. In addition, the counter ion was substituted by degradable excipients such as phosphatidic acid derivatives. Successful implementation has proven the counter-ion concept to be a platform concept that can be successfully implemented for a variety of active substances and counter-ions to enhance drug loading in nanocarriers. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Proximity Within Interphase Chromosome Contributes to the Breakpoint Distribution in Radiation-Induced Intrachromosomal Exchanges

    Science.gov (United States)

    Zhang, Ye; Uhlemeyer, Jimmy; Hada, Megumi; Asaithamby, A.; Chen, David J.; Wu, Honglu

    2015-01-01

    Previously, we reported that breaks involved in chromosome aberrations were clustered in several regions of chromosome3 in human mammary epithelial cells after exposures to either low-or high-LET radiation. In particular, breaks in certain regions of the chromosome tended to rejoin with each other to form an intrachromosome exchange event. This study tests the hypothesis that proximity within a single chromosome in interphase cell nuclei contributes to the distribution of radiation-induced chromosome breaks. Chromosome 3 in G1 human mammary epithelial cells was hybridized with the multicolor banding in situ hybridization (mBAND) probes that distinguish the chromosome in six differently colored regions, and the location of these regions was measured with a laser confocal microscope. Results of the study indicated that, on a multi-mega base pair scale of the DNA, the arrangement of chromatin was non-random. Both telomere regions tended to be located towards the exterior of the chromosome domain, whereas the centromere region towards the interior. In addition, the interior of the chromosome domain was preferentially occupied by the p-arm of the chromatin, which is consistent with our previous finding of intrachromosome exchanges involving breaks on the p-arm and in the centromere region of chromosome3. Other factors, such as the fragile sites in the 3p21 band and gene regulation, may also contribute to the breakpoint distribution in radiation-induced chromosome aberrations. Further investigations suggest that the 3D chromosome folding is cell type and culture condition dependent.

  15. Citizen science contributes to our knowledge of invasive plant species distributions

    Science.gov (United States)

    Crall, Alycia W.; Jarnevich, Catherine S.; Young, Nicholas E.; Panke, Brendon; Renz, Mark; Stohlgren, Thomas

    2015-01-01

    Citizen science is commonly cited as an effective approach to expand the scale of invasive species data collection and monitoring. However, researchers often hesitate to use these data due to concerns over data quality. In light of recent research on the quality of data collected by volunteers, we aimed to demonstrate the extent to which citizen science data can increase sampling coverage, fill gaps in species distributions, and improve habitat suitability models compared to professionally generated data sets used in isolation. We combined data sets from professionals and volunteers for five invasive plant species (Alliaria petiolata, Berberis thunbergii, Cirsium palustre, Pastinaca sativa, Polygonum cuspidatum) in portions of Wisconsin. Volunteers sampled counties not sampled by professionals for three of the five species. Volunteers also added presence locations within counties not included in professional data sets, especially in southern portions of the state where professional monitoring activities had been minimal. Volunteers made a significant contribution to the known distribution, environmental gradients sampled, and the habitat suitability of P. cuspidatum. Models generated with professional data sets for the other four species performed reasonably well according to AUC values (>0.76). The addition of volunteer data did not greatly change model performance (AUC > 0.79) but did change the suitability surface generated by the models, making them more realistic. Our findings underscore the need to merge data from multiple sources to improve knowledge of current species distributions, and to predict their movement under present and future environmental conditions. The efficiency and success of these approaches require that monitoring efforts involve multiple stakeholders in continuous collaboration via established monitoring networks.

  16. Proximal Soil Sensing - A Contribution for Species Habitat Distribution Modelling of Earthworms in Agricultural Soils?

    Directory of Open Access Journals (Sweden)

    Michael Schirrmann

    Full Text Available Earthworms are important for maintaining soil ecosystem functioning and serve as indicators of soil fertility. However, detection of earthworms is time-consuming, which hinders the assessment of earthworm abundances with high sampling density over entire fields. Recent developments of mobile terrestrial sensor platforms for proximal soil sensing (PSS provided new tools for collecting dense spatial information of soils using various sensing principles. Yet, the potential of PSS for assessing earthworm habitats is largely unexplored. This study investigates whether PSS data contribute to the spatial prediction of earthworm abundances in species distribution models of agricultural soils.Proximal soil sensing data, e.g., soil electrical conductivity (EC, pH, and near infrared absorbance (NIR, were collected in real-time in a field with two management strategies (reduced tillage / conventional tillage and sandy to loam soils. PSS was related to observations from a long-term (11 years earthworm observation study conducted at 42 plots. Earthworms were sampled from 0.5 x 0.5 x 0.2 m³ soil blocks and identified to species level. Sensor data were highly correlated with earthworm abundances observed in reduced tillage but less correlated with earthworm abundances observed in conventional tillage. This may indicate that management influences the sensor-earthworm relationship. Generalized additive models and state-space models showed that modelling based on data fusion from EC, pH, and NIR sensors produced better results than modelling without sensor data or data from just a single sensor. Regarding the individual earthworm species, particular sensor combinations were more appropriate than others due to the different habitat requirements of the earthworms. Earthworm species with soil-specific habitat preferences were spatially predicted with higher accuracy by PSS than more ubiquitous species.Our findings suggest that PSS contributes to the spatial

  17. Rapid and reversible switching between superoleophobicity and superoleophilicity in response to counterion exchange.

    Science.gov (United States)

    Yang, Jin; Zhang, Zhaozhu; Men, Xuehu; Xu, Xianghui; Zhu, Xiaotao; Zhou, Xiaoyan; Xue, Qunji

    2012-01-15

    We use a simple layer-by-layer (LbL) assembly and counterion exchange technology to rapidly and reversibly manipulate the oleophobicity of the textured aluminum surfaces. Such textured surfaces can be produced by the HCl etching and boiling water treatment of the flat aluminum plates. The LbL deposition of polyelectrolytes is performed on these surfaces to generate the polyelectrolyte multilayer films. The films are able to coordinate with perfluorooctanoate anions, leading to the surfaces with different oleophobicity. The resulting surface produced by 1.5 cycles of polyelectrolyte deposition exhibits superoleophobicity by displaying contact angles greater than 150° with low surface tension liquids. Counterion exchange in this polyelectrolyte multilayer emerged easily to control the surface composition, which leads to tunable wettability that can be rapidly and reversibly switched between superoleophobicity and superoleophilicity.

  18. Scaling and Universality in the Counterion-Condensation Transition at Charged Cylinders

    OpenAIRE

    Naji, Ali; Netz, Roland R.

    2005-01-01

    We address the critical and universal aspects of counterion-condensation transition at a single charged cylinder in both two and three spatial dimensions using numerical and analytical methods. By introducing a novel Monte-Carlo sampling method in logarithmic radial scale, we are able to numerically simulate the critical limit of infinite system size (corresponding to infinite-dilution limit) within tractable equilibration times. The critical exponents are determined for the inverse moments o...

  19. The role of counterion on the thermotropic phase behavior of DODAB and DODAC vesicles.

    Science.gov (United States)

    Feitosa, Eloi; Alves, Fernanda Rosa

    2008-11-01

    Dioctadecyldimethylammonium bromide and chloride surfactants (DODAX, X representing Br(-) or Cl(-) counterions) assemble in water, above their melting temperatures (T(m)), as cationic unilamellar vesicles at the typical surfactant concentration of 1.0mM. The larger T(m) of DODAC (49 degrees C) relative to DODAB (45 degrees C) has been attributed to the differing affinity and binding specificity of the counterions to the vesicle interfaces. In this communication it is reported differential scanning calorimetry (DSC), conductimetry and dynamic light scattering (DLS) data for mixtures of DODAB and DODAC in water at 1.0mM total surfactant concentration and varying surfactant concentration, to investigate the effect of counterion on the pre-, main- and post-transition temperatures (T(s), T(m) and T(p)), and the data compared to the neat surfactants in water. Accordingly, T(m) increases sigmoidally from 45.8 to 48.9 degrees C when DODAC molar fraction (x(DODAC)) is varied from 0 to 1. Neat DODAB exhibits in addition to T(m), T(s) and T(p) that are inhibited by DODAC. The main peak width DeltaT(1/2) does not depend on the surfactant molar fraction but the melting enthalpy change DeltaH is smaller for DODAB-rich dispersions due to the stronger affinity of Br(-). The conductivity and the apparent hydrodynamic diameter as well do not vary much with x(DODAB), indicating that the surface charge density is similar for DODAB and DODAC, evidencing the role of the counterion binding specificity and affinity on the properties of DODAX vesicles.

  20. Subnational distribution of average farm size and smallholder contributions to global food production

    Science.gov (United States)

    Samberg, Leah H.; Gerber, James S.; Ramankutty, Navin; Herrero, Mario; West, Paul C.

    2016-12-01

    Smallholder farming is the most prevalent form of agriculture in the world, supports many of the planet’s most vulnerable populations, and coexists with some of its most diverse and threatened landscapes. However, there is little information about the location of small farms, making it difficult both to estimate their numbers and to implement effective agricultural, development, and land use policies. Here, we present a map of mean agricultural area, classified by the amount of land per farming household, at subnational resolutions across three key global regions using a novel integration of household microdata and agricultural landscape data. This approach provides a subnational estimate of the number, average size, and contribution of farms across much of the developing world. By our estimates, 918 subnational units in 83 countries in Latin America, sub-Saharan Africa, and South and East Asia average less than five hectares of agricultural land per farming household. These smallholder-dominated systems are home to more than 380 million farming households, make up roughly 30% of the agricultural land and produce more than 70% of the food calories produced in these regions, and are responsible for more than half of the food calories produced globally, as well as more than half of global production of several major food crops. Smallholder systems in these three regions direct a greater percentage of calories produced toward direct human consumption, with 70% of calories produced in these units consumed as food, compared to 55% globally. Our approach provides the ability to disaggregate farming populations from non-farming populations, providing a more accurate picture of farming households on the landscape than has previously been available. These data meet a critical need, as improved understanding of the prevalence and distribution of smallholder farming is essential for effective policy development for food security, poverty reduction, and conservation agendas.

  1. Counterion condensation of differently flexible polyelectrolytes in aqueous solutions in the dilute and semidilute regime.

    Science.gov (United States)

    Truzzolillo, D; Bordi, F; Cametti, C; Sennato, S

    2009-01-01

    The low-frequency limit of the electrical conductivity (dc conductivity) of differently flexible polyions in aqueous solutions has been measured over an extended polyion concentration range, covering both the dilute and semidilute (entangled and unentangled) regime, up to the concentrated regime. The data have been analyzed taking into account the different flexibility of the polymer chains according to the scaling theory of polyion solutions, in the case of flexible polyions, and according to the Manning model, in the case of rigid polyions. In both cases, the fraction f of free counterions, released into the aqueous phase from the ionizable polyion groups, has been evaluated and its dependence on the polyion concentration determined. Our results show that the counterion condensation follows at least three different regimes in dependence on the polyion concentration. The fraction f of free counterions remains constant only in the semidilute regime (a region that we have named the Manning regime), while there is a marked dependence on the polyion concentration both in the dilute and in the concentrated regime. These results are briefly discussed in the light of the scaling theory of polyelectrolyte aqueous solutions.

  2. Opposite counter-ion effects on condensed bundles of highly charged supramolecular nanotubes in water.

    Science.gov (United States)

    Wei, Shenghui; Chen, Mingming; Wei, Chengsha; Huang, Ningdong; Li, Liangbin

    2016-07-20

    Although ion specificity in aqueous solutions is well known, its manifestation in unconventional strong electrostatic interactions remains implicit. Herein, the ionic effects in dense packing of highly charged polyelectrolytes are investigated in supramolecular nanotube prototypes. Distinctive behaviors of the orthorhombic arrays composed of supramolecular nanotubes in various aqueous solutions were observed by Small Angle X-ray Scattering (SAXS), depending on the counter-ions' size and affiliation to the surface -COO(-) groups. Bigger tetra-alkyl ammonium (TAA(+)) cations weakly bonding to -COO(-) will compress the orthorhombic arrays, while expansion is induced by smaller alkaline metal (M(+)) ions with strong affiliation to -COO(-). Careful analysis of the changes in the SAXS peaks with different counter/co-ion combinations indicates dissimilar mechanisms underlying the two explicit types of ionic effects. The pH measurements are in line with the ion specificity by SAXS and reveal the strong electrostatic character of the system. It is proposed that the small distances between the charged surfaces, in addition to the selective adsorption of counter-ions by the surface charge, bring out the observed distinctive ionic effects. Our results manifest the diverse mechanisms and critical roles of counter-ion effects in strong electrostatic interactions.

  3. Binding structure and kinetics of surfactin monolayer formed at the air/water interface to counterions: A molecular dynamics simulation study.

    Science.gov (United States)

    Gang, Hongze; Liu, Jinfeng; Mu, Bozhong

    2015-10-01

    The binding structure and kinetics of ionized surfactin monolayer formed at the air/water interface to five counterions, Li+, Na+, K+, Ca2+, and Ba2+ (molar ratios of surfactin to monovalent and divalent counterions are 1:2 and 1:1 respectively), have been studied using molecular dynamics simulation. The results show that surfactin exhibits higher binding affinity to divalent counterions, Ca2+, and Ba2+, and smaller monovalent counterion, Li+, than Na+ and K+. Both carboxyl groups in surfactin are accessible for counterions, but the carboxyl group in Glu1 is easier to access by counterions than Asp5. Salt bridges are widely built between carboxyl groups by counterions, and the probability of the formation of intermolecular salt bridge is markedly larger than that of intramolecular salt bridge. Divalent counterions perform well in forming salt bridges between carboxyl groups. The salt bridges mediated by Ca2+ are so rigid that the lifetimes are about 0.13 ns, and the break rates of these salt bridges are 1-2 orders of magnitude smaller than those mediated by K+ which is about 5 ps in duration. The positions of the hydration layer of carboxyl groups are independent of counterions, but the bound counterions induce the dehydration of carboxyl groups and disturb the hydrogen bonds built between carboxyl group and hydration water.

  4. Contribution of biomass and biofuel emissions to trace gas distributions in Asia during the TRACE-P experiment

    Science.gov (United States)

    Woo, Jung-Hun; Streets, David G.; Carmichael, Gregory R.; Tang, Youhua; Yoo, Bongin; Lee, Won-Chan; Thongboonchoo, Narisara; Pinnock, Simon; Kurata, Gakuji; Uno, Itsushi; Fu, Qingyan; Vay, Stephanie; Sachse, Glen W.; Blake, Donald R.; Fried, Alan; Thornton, Donald C.

    2003-11-01

    A comprehensive emission inventory with enhanced spatial and temporal resolution is used to help quantify the contribution from three source categories (fossil, biofuel, and biomass burning) during the NASA TRACE-P experiment. Daily biomass burning emissions are developed to support this analysis. Emissions of 27 species and their ratios, by sector, region, and source category are presented. The emission distributions and chemical composition are further analyzed using various statistical techniques. Using cluster analysis, the 27 chemical species are combined into 8 groups that have similar regional distribution, and 52 regions are assembled into 11 regional groups that have similar chemical composition. These groups are used in Chemical Mass Balance analysis to characterize air masses and to quantify the contribution of the three source categories to the observed species distributions. Five DC8 flights with 16 flight segments associated with outflow events are analyzed. In general, Asian outflow is a complex mixture of biofuel, biomass, and fossil sources. Flights in the post frontal regions at high latitudes and low altitudes have a high contribution of fossil fuel emissions. Flights in the warm sector of cold fronts are dominated by biomass burning contributions (about 70%). Biofuel contributions are high (about 70%) when air masses come from central China. The receptor model results are shown to be consistent with other 3-D chemical model sensitivity studies and analysis using ratios of indicator species (e.g., dK+/dSO42-, CH3CN/SOy, SOy/CO, and C2Cl4/CO).

  5. The economic contribution of the Northern Ontario School of Medicine to communities participating in distributed medical education.

    Science.gov (United States)

    Hogenbirk, John C; Robinson, David R; Hill, Mary Ellen; Pong, Raymond W; Minore, Bruce; Adams, Ken; Strasser, Roger P; Lipinski, Joe

    2015-01-01

    The economic contribution of medical schools to major urban centres can be substantial, but there is little information on the contribution to the economy of participating communities made by schools that provide education and training away from major cities and academic health science centres. We sought to assess the economic contribution of the Northern Ontario School of Medicine (NOSM) to northern Ontario communities participating in NOSM's distributed medical education programs. We developed a local economic model and used actual expenditures from 2007/08 to assess the economic contribution of NOSM to communities in northern Ontario. We also estimated the economic contribution of medical students or residents participating in different programs in communities away from the university campuses. To explore broader economic effects, we conducted semistructured interviews with leaders in education, health care and politics in northern Ontario. The total economic contribution to northern Ontario was $67.1 million based on $36.3 million in spending by NOSM and $1.0 million spent by students. Economic contributions were greatest in the university campus cities of Thunder Bay ($26.7 million) and Sudbury ($30.4 million), and $0.8-$1.2 million accrued to the next 3 largest population centres. Communities might realize an economic contribution of $7300-$103 900 per pair of medical learners per placement. Several of the 59 interviewees remarked that the dollar amount could be small to moderate but had broader economic implications. Distributed medical education at the NOSM resulted in a substantial economic contribution to participating communities.

  6. Determinants of vegetation distribution at continental scale. The contribution of natural and anthropogenic factors

    DEFF Research Database (Denmark)

    Greve, Michelle; Svenning, J.-C.; Lykke, Anne Mette

    2011-01-01

    It has long been debated what determines distribution of vegetation types, though this has rarely been tested at continental scale. We thus aimed to determine which vegetation types are most accurately predicted by natural environmental factors, and which of these factors best predict current...... vegetation distribution across Africa. Vegetation types were extracted from the Global Land Cover Map for the year 2000, and the distribution of vegetation types modelled in terms of climate, soil and topography. Annual precipitation was the best predictor of the distribution of all vegetation types...... was also assessed, and found to be of some importance for most vegetation types. We conclude that, in addition to including environmental variables in predicting vegetation distribution, it is essential that human impact be considered, also in future climate change scenarios....

  7. The contributions of resource availability and social forces to foraging distributions: a spatial lag modelling approach

    NARCIS (Netherlands)

    Folmer, E.O.; Piersma, T.

    2012-01-01

    The spatial distribution of foraging animals at a given time simultaneously depends on (1) exogenous environmental variables such as resource availability and abiotic habitat characteristics, and (2) the endogenous variable social aggregation made up of the opposing mechanisms of conspecific

  8. The contributions of resource availability and social forces to foraging distributions : a spatial lag modelling approach

    NARCIS (Netherlands)

    Folmer, Eelke O.; Piersma, Theunis

    2012-01-01

    The spatial distribution of foraging animals at a given time simultaneously depends on (1) exogenous environmental variables such as resource availability and abiotic habitat characteristics, and (2) the endogenous variable social aggregation made up of the opposing mechanisms of conspecific

  9. Viscoelasticity Enhancement of Surfactant Solutions Depends on Molecular Conformation: Influence of Surfactant Headgroup Structure and Its Counterion.

    Science.gov (United States)

    Lutz-Bueno, Viviane; Pasquino, Rossana; Liebi, Marianne; Kohlbrecher, Joachim; Fischer, Peter

    2016-05-03

    During the anisotropic growth from globular to wormlike micelles, the basic interactions among distinct parts of the surfactant monomer, its counterion, and additives are fundamental to tune molecular self-assembly. We investigate the addition of sodium salicylate (NaSal) to hexadecyltrimethylammonium chloride and bromide (CTAC and CTAB), 1-hexadecylpyridinium chloride and bromide (CPyCl and CPyBr), and benzyldimethylhexadecylammonium chloride (BDMC), which have the same hydrophobic tail. Their potential to enhance viscoelasticity by anisotropic micellar growth upon salt addition was compared in terms of (i) the influence of the headgroup structure, and (ii) the influence of surfactant counterion type. Employing proton nuclear magnetic resonance ((1)H NMR), we focused on the molecular conformation of surfactant monomers in the core and polar shell regions of the micelles and their interactions with increasing concentration of NaSal. The viscoelastic response was investigated by rotational and oscillatory rheology. We show that micellar growth rates can be tuned by varying the flexibility and size of the surfactant headgroup as well as the dissociation degree of the surfactant counterion, which directly influences the strength of headgroup-counterion pairing. As a consequence, the morphological transitions depend directly on charge neutralization by electrostatic screening. For example, the amount of salt necessary to start the rodlike-to-wormlike micelle growth depends directly on the number of dissociated counterions in the polar shell.

  10. Modulation of Tartrates with Various Counterions on the Phases of Calcium Oxalate in Gelatinous Systems

    Institute of Scientific and Technical Information of China (English)

    Jian Ming OUYANG; Xiang Ping LI

    2005-01-01

    Effect of various counterions of tartrate on the crystallization of calcium oxalate in gel system was investigated using scanning electron microscopy and X-ray diffraction. Various tartrates with hydrogen (H2tart), sodium (Na2tart), potassium (K2tart), ammonium ((NH4)2tart), and a mixture of sodium and potassium cations (NaKtart) were considered. For H2tart, Na2tart, and (NH4)2tart, calcium oxalate dihydrate (COD) was induced. However, for K2tart and NaKtart,calcium oxalate trihydrate (COT) was obtained.

  11. N-heterocyclic carbene catalyzed asymmetric intermolecular Stetter reaction: origin of enantioselectivity and role of counterions.

    Science.gov (United States)

    Kuniyil, Rositha; Sunoj, Raghavan B

    2013-10-04

    The mechanism and the role of KOtBu in an enantioselective NHC-catalyzed Stetter reaction between p-chlorobenzaldehyde and N-acylamido acrylate is established using DFT(M06-2X) methods. The Gibbs free energies are found to be significantly lower for transition states with explicit bound KOtBu as compared to the conventional pathways without the counterions. An intermolecular proton transfer from HOtBu to the prochiral carbon is identified as the stereocontrolling step. The computed enantioselectivities are in excellent agreement with the experimental results.

  12. A Rigid Nested Metal-Organic Framework Featuring a Thermoresponsive Gating Effect Dominated by Counterions.

    Science.gov (United States)

    Gao, Qiang; Xu, Jian; Cao, Dapeng; Chang, Ze; Bu, Xian-He

    2016-11-21

    We herein report a rigid nested metal-organic framework (MOF) featuring a unique thermoresponsive gating adsorption behavior, which, in contrast to any known flexibility modes for stimuli-responsive MOFs, depends on the thermal motion of the extra-framework counterions. In addition, this MOF also exhibits adsorption selectivity of CO2 over N2 , H2 , and Ar at 273 K, thus enabling a strategic separation and encapsulation of CO2 . © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Cation-π Interaction between the Aromatic Organic Counterion and DTAB Micelle in Mixed Solvents

    Institute of Scientific and Technical Information of China (English)

    DENG,Dong-Shun(邓东顺); LI,Hao-Ran(李浩然); LIU,Di-Xia(刘迪霞); HAN,Shi-Jun(韩世钧)

    2004-01-01

    The cation-π interaction between the aromatic organic counterion potassium hydrogen phthalate (KHP) and DTAB micelle in aqueous mixture of EG was investigated, using the techniques of conductivity measurements, UV absorption spectrum and NMR spectrum. The conductivity and UV spectrum studies were with respect to the effect of KHP on DTAB and that of DTAB micelle on KHP, respectively. According to the chemical shift changes of the aromatic ring and the surfactant methylene protons, it can be assumed that KHP penetrated into DTAB micelle with its carboxylic group protruding out of the micellar surface. And the strength of the interaction became weaker with the content of EG in the mixed solvent increasing.

  14. Distribution and physiology of ABC-Type transporters contributing to multidrug resistance in bacteria

    NARCIS (Netherlands)

    Lubelski, Jacek; Konings, Wil N.; Driessen, Arnold J. M.

    2007-01-01

    Membrane proteins responsible for the active efflux of structurally and functionally unrelated drugs were first characterized in higher eukalyotes. To date, a vast number of transporters contributing to multidrug resistance (MDR transporters) have been reported for a large variety of organisms. Pred

  15. Determining the Contribution of Gas Emissions from Cars and Estimating the Distribution of CO Emissions in Enclosed Parking

    Directory of Open Access Journals (Sweden)

    Kh Ashrafi

    2016-03-01

    Full Text Available Background and Objectives: In this study, contribution of exhaust emission and CO distribution was estimated in enclosed residential complex parking. Materials and Methods: This was a descriptive - analytical study consisted of two stages. In the first stage, the emission contribution of vehicles was determined. In order to determine the contribution of exhaust gas emissions, through gas species, only four species CO, O2, CO2, and N2 were measured. Concentration of CO, O2, and CO2 was estimated using data obtained from the vehicle emissions monitoring system. The amount of N2 was estimated from sum ratio of all species, which equals to 1. Then, using computational methods, the amount of the emission contribution from vehicles. In the second phase, to measure the distribution of CO pollutant, gas sampling and collecting was performed using sampling bags made of inert materials with a volume of 10 l at six points. Sampling was conducted in accordance with the requirements of OSHA ID 210. The Obtained data were analyzed using SPSS Ver.16 software and Pearson statistical test (P > 0.05 means there was no significant difference. Results: Maximum contribution was estimated for Pride with amount of 44.4 g/s and minimum contribution was estimated for Tiba with amount of 0.3 g/s. The minimum and maximum distribution value of CO concentration was achieved 3.6 and 69.48 ppm respectively. It was found that no significant relationship was observed between the values of exhaust emissions and CO distribution. However, the distribution of concentration was associated with locations and the number of openings, the number and type of vehicle, time of operation of the vehicle, the vehicle performance, and environmental factors. Conclusion: Measuring vehicles CO emission indicated  that the concentration was beyond the permissible level recommended by the World Health Organization at some. Moreover, it was indicated that natural air conditioning is an effective

  16. 26 CFR 1.401(a)(9)-5 - Required minimum distributions from defined contribution plans.

    Science.gov (United States)

    2010-04-01

    ... the case of distributions to be made in accordance with the life expectancy rule in § 1.401(a)(9)-3... period determined in accordance with paragraph (a) of this A-4 or the joint life expectancy of the...) The remaining life expectancy of the employee's designated beneficiary determined in accordance...

  17. Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction

    CERN Document Server

    Wunderlich, Y; Thiel, A; Beck, R

    2016-01-01

    This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson photoproduction. First, fits to angular distributions are presented and the maximum orbital angular momentum $\\text{L}_{\\mathrm{max}}$ needed to achieve a good fit is determined. Then, recent polarization measurements for $\\gamma p \\rightarrow \\pi^{0} p$ from ELSA, GRAAL, JLab and MAMI are investigated according to the proposed method. This method allows us to project high-spin partial wave contributions to any observable as long as the measurement has the necessary statistical accuracy. We show, that high precision and large angular coverage in the polarization data are needed in order to be sensitive to high-spin resonance-states and thereby also for the finding of small resonance contributions. This task can be achieved via interference of these resonances with the well-known states. For the channel $\\gamma p \\rightarrow \\pi^{0} p$, those are the $N(1680)...

  18. Size distribution of black spot defects and their contribution to swelling in irradiated SiC

    Energy Technology Data Exchange (ETDEWEB)

    Tyburska-Püschel, B., E-mail: tyburska@engr.wisc.edu [University of Wisconsin-Madison, Department of Engineering Physics, 1500 Engineering Dr., Madison, WI 53706 (United States); Zhai, Y.; He, L.; Liu, C. [University of Wisconsin-Madison, Department of Material Science, 1509 University Ave., Madison, WI 53706 (United States); Boulle, A. [Science des Procédés Céramiques et Traitements de Surface, CNRS UMR 7315, Centre Européen de la Céramique, 12 Rue Atlantis, 80768 Limoges (France); Voyles, P.M. [University of Wisconsin-Madison, Department of Material Science, 1509 University Ave., Madison, WI 53706 (United States); Szlufarska, I. [University of Wisconsin-Madison, Department of Engineering Physics, 1500 Engineering Dr., Madison, WI 53706 (United States); University of Wisconsin-Madison, Department of Material Science, 1509 University Ave., Madison, WI 53706 (United States); Sridharan, K. [University of Wisconsin-Madison, Department of Engineering Physics, 1500 Engineering Dr., Madison, WI 53706 (United States)

    2016-08-01

    Experimental and modeling efforts were combined to investigate the role of black spot defects (BSD) in swelling of carbon- and krypton-irradiated 4H-SiC. Samples were exposed to conditions favoring BSD formation: irradiation at temperatures 600–950 °C and damage levels of 0.4–0.8 dpa. The maximum XRD swelling values, corrected for the effect of the rigid substrate, of 0.58% for C and 0.75% for Kr-irradiation were measured at the lowest irradiation temperature of 600  °C and decreased with increasing temperature. The swelling values estimated from TEM are on the same order of magnitude, but usually 40–70% lower than those measured by XRD. The contribution of BSDs to the overall swelling is 62% and the remainder of the swelling is caused by isolated point defects. The obtained results contribute to understanding of what defect types account for swelling and how their concentration evolves with the irradiation temperature and damage level. - Highlights: • We investigated the role of black spot defects (BSD) in swelling of ion-irradiated 4H-SiC. • Swelling by XRD is corrected for the effect of the rigid substrate. • BSDs contributes 62% to the overall swelling and the remainder is caused by isolated point defects. • Swelling from TEM is lower by 40% to 70% than the XRD values.

  19. Counterion identity effects on the self-assembly processes in a series of perfluorinated surfactant-water mixtures

    CERN Document Server

    Zhou, R

    2003-01-01

    The effects of counterion on the lyotropic liquid crystalline phase behaviour of some quaternary ammonium salts of perfluorodecanoic acid in water have been studied using a combination of optical polarising microscopy (OPM), deuterium nuclear magnetic resonance ( sup 2 H NMR) and cryo-transmission electron microscopy (cryo-TEM). The results from the phase diagram studies fall into two groups. Firstly the ammonium (A) and tetramethylammonium (TMA) counterions show a phase behaviour with nematic (N) and random mesh (Mh sub 1 (0)) phase which possess non-uniform interfacial curvature. The second group of surfactants with counterions, butyltrimethylammonium (BTMA), dibutyidimetylammonium (DBDMA), and tetrabutylammonium (TEA), form only a classical lamellar phase (L subalpha). For both DBDMA and TBA lower consolute behaviour has been observed. At fixed concentration in all five systems cryo-TEM visualises isotropic liquid phase structures that vary from sphere / rod micelles for A and TMA to vesicles / bilayer pie...

  20. Contribution to the knowledge for distribution of Criodrilus lacuum (Annelida: Oligochaeta: Criodrilidae from Bulgaria

    Directory of Open Access Journals (Sweden)

    Hristo Valchovski

    2013-10-01

    Full Text Available All known records of Criodrilidae earthworms in the country were presented. The current knowledge for distribution of family Criodrilidae in Bulgaria was summarized. In this paper we report new locality of Criodrilus lacuum Hoffmeister, 1845. Surprisingly this species was found in one of the parks in Sofia Town. New data confirm its presence in Sofia Plane. Also information about ecology, habitat type locality and short description of Criodrilus lacuum was provided.

  1. Contribution to the knowledge for distribution of Criodrilus lacuum (Annelida: Oligochaeta: Criodrilidae) from Bulgaria

    OpenAIRE

    Hristo Valchovski

    2013-01-01

    All known records of Criodrilidae earthworms in the country were presented. The current knowledge for distribution of family Criodrilidae in Bulgaria was summarized. In this paper we report new locality of Criodrilus lacuum Hoffmeister, 1845. Surprisingly this species was found in one of the parks in Sofia Town. New data confirm its presence in Sofia Plane. Also information about ecology, habitat type locality and short description of Criodrilus lacuum was provided.

  2. Contribution of static and dynamic load balancing in a real-time distributed air defence simulation

    CSIR Research Space (South Africa)

    Duvenhage, B

    2008-05-01

    Full Text Available and Dynamic Load Balancing In A Real-Time Distributed Air Defence Simulation Mr Bernardt Duvenhage; Mr Jan J. Nel Council for Scientific and Industrial Research (CSIR) bduvenhage@csir.co.za, cnel@csir.co.za Abstract. Simulations with a large number... system. The measure to which dynamic load balancing could further enhance the performance is then explored. Such knowledge forms the basis for further load balance research. 1. INTRODUCTION The South African Council for Scientific and Industrial...

  3. Water-soluble organic carbon in urban aerosol: concentrations, size distributions and contribution to particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    Timonen, H. J.; Saarikoski, S. K.; Aurela, M. A.; Saarnio, K. M.; Hillamo, R. E. (Finnish Meteorological Inst., Helsinki (Finland))

    2008-07-01

    The aim of this study was to characterize the concentrations and particle mass size distributions of water-soluble organic carbon (WSOC) in urban aerosols. The sample collection was carried out in spring 2006 at the SMEAR III station in Helsinki, Finland, by using a size-segregating method (MOUDI) and by collecting sub-micrometer fraction of aerosols on the filter. During the three-month measurement period, a major 12-day biomass burning pollution episode was observed. Concentrations of WSOC, organic carbon, monosaccharide anhydrides, inorganic ions and some organic acids (oxalic, succinic and malonic acid) were analyzed from the PM{sub 1} samples. The measured OC and WSOC concentrations varied in ranges 0.67-15.7 mug m-3 and 0.26-10.7 mug m3, respectively. The WSOC/OC concentration ratio was between 0.30 and 0.89 with an average of 0.54. Size distributions of WSOC, inorganic ions and total mass were determined from the MOUDI samples. WSOC had bimodal size distributions with a clear accumulation mode below 1 mum of particle aerodynamic diameter and minor coarse mode at sizes > 1 mum. (orig.)

  4. Assessing the contribution of microgrids to the reliability of distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Moises [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal); Matos, Manuel A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2009-02-15

    The emergence of microgeneration has recently lead to the concept of microgrid, a network of LV consumers and producers able to export electric energy in some circumstances and also to work in an isolated way in emergency situations. Research on the organization of microgrids, control devices, functionalities and other technical aspects is presently being carried out, in order to establish a consistent technical framework to support the concept. The successful development of the microgrid concept implies the definition of a suitable regulation for its integration on distribution systems. In order to define such a regulation, the identification of costs and benefits that microgrids may bring is a crucial task. Actually, this is the basis for a discussion about the way global costs could be divided among the different agents that benefit from the development of microgrids. Among other aspects, the effect of microgrids on the reliability of the distribution network has been pointed out as an important advantage, due to the ability of isolated operation in emergency situations. This paper identifies the situations where the existence of a microgrid may reduce the interruption rate and duration and thus improve the reliability indices of the distribution network. The relevant expressions necessary to quantify the reliability are presented. An illustrative example is included, where the global influence of the microgrid in the reliability is commented. (author)

  5. Collective fluorescence switching of counterion-assembled dyes in polymer nanoparticles

    Science.gov (United States)

    Reisch, Andreas; Didier, Pascal; Richert, Ludovic; Oncul, Sule; Arntz, Youri; Mély, Yves; Klymchenko, Andrey S.

    2014-06-01

    The current challenge in the field of fluorescent nanoparticles (NPs) for bioimaging is to achieve extreme brightness and external control of their emission using biodegradable materials. Here we propose a new concept of fluorescent polymer NPs, doped with ionic liquid-like salts of a cationic dye (octadecyl rhodamine B) with a bulky hydrophobic counterion (fluorinated tetraphenylborate) that serves as spacer minimizing dye aggregation and self-quenching. The obtained 40-nm poly(D,L-lactide-co-glycolide) NPs containing up to 500 dyes are brighter than quantum dots and exhibit photo-induced reversible on/off fluorescence switching, never reported for dye-doped NPs. We show that this collective switching of hundreds of dyes is due to ultrafast excitation energy transfer and can be used for super-resolution imaging. These NPs, being spontaneously endocytosed by living cells, feature high signal-to-noise ratio and absence of toxicity. The counterion-based concept opens the way to a new class of nanomaterials for sensing, imaging and light harvesting.

  6. Poisson-Boltzmann thermodynamics of counterions confined by curved hard walls

    Science.gov (United States)

    Šamaj, Ladislav; Trizac, Emmanuel

    2016-01-01

    We consider a set of identical mobile pointlike charges (counterions) confined to a domain with curved hard walls carrying a uniform fixed surface charge density, the system as a whole being electroneutral. Three domain geometries are considered: a pair of parallel plates, the cylinder, and the sphere. The particle system in thermal equilibrium is assumed to be described by the nonlinear Poisson-Boltzmann theory. While the effectively one-dimensional plates and the two-dimensional cylinder have already been solved, the three-dimensional sphere problem is not integrable. It is shown that the contact density of particles at the charged surface is determined by a first-order Abel differential equation of the second kind which is a counterpart of Enig's equation in the critical theory of gravitation and combustion or explosion. This equation enables us to construct the exact series solutions of the contact density in the regions of small and large surface charge densities. The formalism provides, within the mean-field Poisson-Boltzmann framework, the complete thermodynamics of counterions inside a charged sphere (salt-free system).

  7. Re-entrant phase behavior of a concentrated anionic surfactant system with strongly binding counterions.

    Science.gov (United States)

    Ghosh, Sajal Kumar; Rathee, Vikram; Krishnaswamy, Rema; Raghunathan, V A; Sood, A K

    2009-08-04

    The phase behavior of the anionic surfactant sodium dodecyl sulfate (SDS) in the presence of the strongly binding counterion p-toluidine hydrochloride (PTHC) has been examined using small-angle X-ray diffraction and polarizing microscopy. A hexagonal-to-lamellar transition on varying the PTHC to SDS molar ratio (alpha) occurs through a nematic phase of rodlike micelles (Nc) --> isotropic (I) --> nematic of disklike micelles (N(D)) at a fixed surfactant concentration (phi). The lamellar phase is found to coexist with an isotropic phase (I') over a large region of the phase diagram. Deuterium nuclear magnetic resonance investigations of the phase behavior at phi = 0.4 confirm the transition from N(C) to N(D) on varying alpha. The viscoelastic and flow behaviors of the different phases were examined. A decrease in the steady shear viscosity across the different phases with increasing alpha suggests a decrease in the aspect ratio of the micellar aggregates. From the transient shear stress response of the N() and N(D) nematic phases in step shear experiments, they were characterized to be tumbling and flow aligning, respectively. Our studies reveal that by tuning the morphology of the surfactant micelles strongly binding counterions modify the phase behavior and rheological properties of concentrated surfactant solutions.

  8. Interactions of univalent counterions with headgroups of monomers and dimers of an anionic surfactant.

    Science.gov (United States)

    Jakubowska, Anna

    2015-03-24

    Specific ion effects in solution are related to the hydrated ion size and ion hydration, electrostatic interactions, dispersion forces, ion effects on water structure, and ion modification of surface tension. In this study, we tried to identify which factor determines the ion specificity observed. The preference and energy of metal cations binding with the headgroups of dodecylsulfate (DS) monomers and dimers were determined by mass spectrometry. In the gas phase, cation binding to DS dimer headgroups depends strongly on the cation radius. On the other hand, the interactions between DS monomer headgroups and chaotropic ions depend on the cation polarizability, and the binding of kosmotropic cations to DS monomer headgroups strongly depends on the Gibbs free energies of ion hydration. DS dimers are related to surfactants having doubly charged headgroups, and DS monomers are related to surfactants with singly charged headgroups. Our spectrometric study of the strength of counterion binding to free monomers of a surfactant provides insight into surfactant-counterion interactions at micellar interfaces in bulk solution.

  9. Large counterions boost the solubility and renormalized charge of suspended nanoparticles.

    Science.gov (United States)

    Guerrero-García, Guillermo Iván; González-Mozuelos, Pedro; Olvera de la Cruz, Monica

    2013-11-26

    Colloidal particles are ubiquitous in biology and in everyday products such as milk, cosmetics, lubricants, paints, or drugs. The stability and aggregation of colloidal suspensions are of paramount importance in nature and in diverse nanotechnological applications, including the fabrication of photonic materials and scaffolds for biological assemblies, gene therapy, diagnostics, targeted drug delivery, and molecular labeling. Electrolyte solutions have been extensively used to stabilize and direct the assembly of colloidal particles. In electrolytes, the effective electrostatic interactions among the suspended colloids can be changed over various length scales by tuning the ionic concentration. However, a major limitation is gelation or flocculation at high salt concentrations. This is explained by classical theories, which show that the electrostatic repulsion among charged colloids is significantly reduced at high electrolyte concentrations. As a result, these screened colloidal particles are expected to aggregate due to short-range attractive interactions or dispersion forces as the salt concentration increases. We discuss here a robust, tunable mechanism for colloidal stability by which large counterions prevent highly charged nanoparticles from aggregating in salt solutions with concentrations up to 1 M. Large counterions are shown to generate a thicker ionic cloud in the proximity of each charged colloid, which strengthens short-range repulsions among colloidal particles and also increases the corresponding renormalized colloidal charge perceived at larger separation distances. These effects thus provide a reliable stabilization mechanism in a broad range of biological and synthetic colloidal suspensions.

  10. Charge Inversion Effects in Electrophoresis of Polyelectrolytes in the Presence of Multivalent Counterions and Transversal Electric Fields

    Directory of Open Access Journals (Sweden)

    Sorin Nedelcu

    2014-12-01

    Full Text Available By molecular dynamics simulations we investigate the transport of charged polymers in confinement, under externally applied electric fields, in straight cylinders of uniform diameter and in the presence of monovalent or multivalent counterions. The applied electric field has two components; a longitudinal component along the axis of the cylinder and a transversal component perpendicular to the cylinder axis. The direction of electrophoretic velocity depends on the polyelectrolyte length, valency of the counterions present in solution and transversal electric field value. A statistical model is put forward in order to explain these observations.

  11. Larval behaviours and their contribution to the distribution of the intertidal coral reef sponge Carteriospongia foliascens.

    Directory of Open Access Journals (Sweden)

    Muhammad Azmi Abdul Wahab

    Full Text Available Sponges (Phylum Porifera are an evolutionary and ecologically significant group; however information on processes influencing sponge population distributions is surprisingly limited. Carteriospongia foliascens is a common Indo-Pacific sponge, which has been reported from the intertidal to the mesophotic. Interestingly, the distribution of C. foliascens at inshore reefs of the Great Barrier Reef is restricted to the intertidal with no individuals evident in adjacent subtidal habitats. The abundance of C. foliascens and substrate availability was first quantified to investigate the influence of substrate limitation on adult distribution. Pre-settlement processes of larval spawning, swimming speeds, phototaxis, vertical migration, and settlement to intertidal and subtidal substrate cues were also quantified. Notably, suitable settlement substrate (coral rubble was not limiting in subtidal habitats. C. foliascens released up to 765 brooded larvae sponge(-1 day(-1 during the day, with larvae (80%±5.77 being negatively phototactic and migrating to the bottom within 40 minutes from release. Subsequently, larvae (up to 58.67%±2.91 migrated to the surface after the loss of the daylight cue (nightfall, and after 34 h post-release >98.67% (±0.67 of larvae had adopted a benthic habit regardless of light conditions. Intertidal and subtidal biofilms initiated similar settlement responses, inducing faster (as early 6 h post-release and more successful metamorphosis (>60% than unconditioned surfaces. C. foliascens has a high larval supply and larval behaviours that support recruitment to the subtidal. The absence of C. foliascens in subtidal habitats at inshore reefs is therefore proposed to be a potential consequence of post-settlement mortalities.

  12. Distribution of Pb-210 in Spanish Soils: Study of the Atmospheric Contribution

    Science.gov (United States)

    Barrera, M.; Cartas, H. A.; Romero, M. L.; Herranz, M.; Valiño, F.; Idoeta, R.; Legarda, F.

    2008-08-01

    The vertical distribution of activity and inventories of atmospheric Pb-210 is being studied in Spanish soils, aiming to establish the reference levels in the zone, based on the type of soil and the annual rainfall. A homogeneous distribution grid (approx. 150×150 km each cell) has been established covering the peninsular land, trying to combine the varying soil types (remaining undisturbed for the last 50 years) and the closeness to meteorological stations. Sampling has been performed by extracting undisturbed soil cylinders of 6 cm diameter and 120 cm length, with an impact penetrometer, and the soil cores have been sectioned in slices of 3 cm thick. The analysis of Pb-210 has been performed using a gamma spectrometry system with coaxial HPGe detector sensitive at low energies (46.5 keV emission). The geometry of measured samples is thin enough (approx. 2 cm) to minimize self-absorption corrections. The work presents the results obtained so far. The Pb-210 activity profiles exhibit the characteristic decreasing shape with depth, showing maximum levels at the surface, and reaching the equilibrium activity with Ra-226 at a maximum depth depending on different environmental conditions. The unsupported Pb-210 inventory values are in the usual range (1000-5000 Bq/m2), showing a positive correlation with the averaged annual rainfall. These reference levels could be used in posterior studies of anthropogenic alteration of soils, evaluation of erosion and desertification processes.

  13. Continuous gene flow contributes to low global species abundance and distribution of a marine model diatom

    KAUST Repository

    Rastogi, Achal

    2017-08-15

    Unlike terrestrial ecosystems where geographical isolation often leads to a restricted gene flow between species, genetic admixing in aquatic micro-eukaryotes is likely to be frequent. Diatoms inhabit marine ecosystems since the Mesozoic period and presently constitute one of the major primary producers in the world ocean. They are a highly diversified group of eukaryotic phytoplankton with estimates of up to 200,000 species. Since decades, Phaeodactylum tricornutum is used as a model diatom species to characterize the functional pathways, physiology and evolution of diatoms in general. In the current study, using whole genome sequencing of ten P. tricornutum strains, sampled at broad geospatial and temporal scales, we show a continuous dispersal and genetic admixing between geographically isolated strains. We also describe a very high level of heterozygosity and propose it to be a consequence of frequent ancestral admixture. Our finding that P. tricornutum sequences are plausibly detectable at low but broadly distributed levels in the world ocean further suggests that high admixing between geographically isolated strains may create a significant bottleneck, thus influencing their global abundance and distribution in nature. Finally, in an attempt to understand the functional implications of genetic diversity between different P. tricornutum ecotypes, we show the effects of domestication in inducing changes in the selection pressure on many genes and metabolic pathways. We propose these findings to have significant implications for understanding the genetic structure of diatom populations in nature and provide a framework to assess the genomic underpinnings of their ecological success.

  14. Distribution of hydrocarbon-degrading bacteria in the soil environment and their contribution to bioremediation.

    Science.gov (United States)

    Fukuhara, Yuki; Horii, Sachie; Matsuno, Toshihide; Matsumiya, Yoshiki; Mukai, Masaki; Kubo, Motoki

    2013-05-01

    A real-time PCR quantification method for indigenous hydrocarbon-degrading bacteria (HDB) carrying the alkB gene in the soil environment was developed to investigate their distribution in soil. The detection limit of indigenous HDB by the method was 1 × 10(6) cells/g-soil. The indigenous HDB were widely distributed throughout the soil environment and ranged from 3.7 × 10(7) to 5.0 × 10(8) cells/g-soil, and the ratio to total bacteria was 0.1-4.3 %. The dynamics of total bacteria, indigenous HDB, and Rhodococcus erythropolis NDKK6 (carrying alkB R2) during bioremediation were analyzed. During bioremediation with an inorganic nutrient treatment, the numbers of these bacteria were slightly increased. The numbers of HDB (both indigenous bacteria and strain NDKK6) were gradually decreased from the middle stage of bioremediation. Meanwhile, the numbers of these bacteria were highly increased and were maintained during bioremediation with an organic nutrient. The organic treatment led to activation of not only the soil bacteria but also the HDB, so an efficient bioremediation was carried out.

  15. Recent contributions to the distribution of the freshwater ichthyofauna in Greece

    Directory of Open Access Journals (Sweden)

    N. KOUTSIKOS

    2013-01-01

    Full Text Available In this paper we supplement Greece’s recent annotated inventory of freshwater fishes per hydrographic basin with recent distributional data and taxa alteration information, based on field sampling and a literature review up to September 2011. We report on newly documented distributional records of 31 fish species plus one unidentified taxon, within 35 hydrographic river basin units in Greece. These new records include 14 native fish species, seven alien and 12 translocated. Translocated taxa are distinguished from aliens, in order to report species non-indigenous to a basin but native within the same ecoregion. Twelve hydrographic basin units are newly added to the roster of ichthyologically explored river basins following a previous basin-scale inventory method (the total is now 117. This review increases the number of Greece’s freshwater fish taxa to 167, since four new species are added to the list (Carassius langsdorfii, Neogobius fluviatilis, Telestes alfiensis, Millerigobius macrocephalus and two are deleted (Salmo dentex, Barbus rebeli due to taxonomic changes. Taxonomic changes will probably continue to alter the national list since phylogenetic research is ongoing on several taxa in many parts of the country

  16. Contribution of ants in modifying of soil acidity and particle size distribution

    Science.gov (United States)

    Morgun, Alexandra; Golichenkov, Maxim

    2015-04-01

    Being a natural body, formed by the influence of biota on the upper layers of the Earth's crust, the soil is the most striking example of biogenic-abiogenic interactions in the biosphere. Invertebrates (especially ants that build soil nests) are important agents that change soil properties in well developed terrestrial ecosystems. Impact of soil microorganisms on soil properties is particularly described in numerous literature and concerns mainly chemical properties and general indicators of soil biological activity. Influence of ants (as representatives of the soil mesofauna) mostly appears as mechanical movement of soil particles and aggregates, and chemical effects caused by concentration of organic matter within the ant's nest. The aim of this research was to evaluate the effect of ants on physical and chemical soil attributes such as particle size distribution and soil acidity. The samples were taken from aerial parts of Lasius niger nests, selected on different elements of the relief (summit position, slope, terrace and floodplain) in the Arkhangelsk region (north of the European part of Russia) and compared with the specimens of the upper horizons of the reference soils. Particle size distribution was determined by laser diffraction method using laser diffraction particle size analyzer «Analysette 22 comfort» (FRITSCH, Germany). The acidity (pH) was determined by potentiometry in water suspension. Particle size distribution of the samples from the nests is more variable as compared to the control samples. For example, the content of 5-10 μm fraction ranges from 9% to 12% in reference soils, while in the anthill samples the variation is from 8% to 15%. Similarly, for 50-250 μm fraction - it ranges from 15% to 18% in reference soils, whereas in anthills - from 6% to 29%. The results of particle size analysis showed that the reference sample on the terrace has silty loam texture and nests soil L. niger are medium loam. The reference soil on the slope is

  17. Species distribution models contribute to determine the effect of climate and interspecific interactions in moving hybrid zones.

    Science.gov (United States)

    Engler, J O; Rödder, D; Elle, O; Hochkirch, A; Secondi, J

    2013-11-01

    Climate is a major factor delimiting species' distributions. However, biotic interactions may also be prominent in shaping geographical ranges, especially for parapatric species forming hybrid zones. Determining the relative effect of each factor and their interaction of the contact zone location has been difficult due to the lack of broad scale environmental data. Recent developments in species distribution modelling (SDM) now allow disentangling the relative contributions of climate and species' interactions in hybrid zones and their responses to future climate change. We investigated the moving hybrid zone between the breeding ranges of two parapatric passerines in Europe. We conducted SDMs representing the climatic conditions during the breeding season. Our results show a large mismatch between the realized and potential distributions of the two species, suggesting that interspecific interactions, not climate, account for the present location of the contact zone. The SDM scenarios show that the southerly distributed species, Hippolais polyglotta, might lose large parts of its southern distribution under climate change, but a similar gain of novel habitat along the hybrid zone seems unlikely, because interactions with the other species (H. icterina) constrain its range expansion. Thus, whenever biotic interactions limit range expansion, species may become 'trapped' if range loss due to climate change is faster than the movement of the contact zone. An increasing number of moving hybrid zones are being reported, but the proximate causes of movement often remain unclear. In a global context of climate change, we call for more interest in their interactions with climate change.

  18. Contribution of material’s surface layer on charge state distribution in laser ablation plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kumaki, Masafumi, E-mail: rogus@asagi.waseda.jp [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Steski, Dannie; Kanesue, Takeshi [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Ikeda, Shunsuke [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa 226-8503 (Japan); Okamura, Masahiro [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Washio, Masakazu [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan)

    2016-02-15

    To generate laser ablation plasma, a pulse laser is focused onto a solid target making a crater on the surface. However, not all the evaporated material is efficiently converted to hot plasma. Some portion of the evaporated material could be turned to low temperature plasma or just vapor. To investigate the mechanism, we prepared an aluminum target coated by thin carbon layers. Then, we measured the ablation plasma properties with different carbon thicknesses on the aluminum plate. The results showed that C{sup 6+} ions were generated only from the surface layer. The deep layers (over 250 nm from the surface) did not provide high charge state ions. On the other hand, low charge state ions were mainly produced by the deeper layers of the target. Atoms deeper than 1000 nm did not contribute to the ablation plasma formation.

  19. Unraveling the Organo-colloidal Control on Trace Element Distribution in Shallow Groundwaters : an Experimental Contribution

    Science.gov (United States)

    Dia, A.; Pedrot, M.; Davranche, M.; Pourret, O.; Petitjean, P.; Henin, O.; Le Coz-Bouhnik, M.

    2006-12-01

    Dissolved Organic Matter (DOM) is ubiquitous in aquatic environments and plays a key role in the geochemistry of major and trace elements - acting as a major carrier and transport phase - through complexation, adsorption, dissolution reactions. It both does interact with mineral phases modifying the exchange rates with solutions and constrain part of pollutant mobilities such as that of trace metals or hydrophobic organic compounds. Not only does association with DOM influences the mobility of metals through the soil/water system, it also regulates their chemical reactivity, bioavailability and toxicity. In order to study DOM-metal interactions and the role of the colloidal pool in such groundwaters, DOM-rich soil/water interactions were performed (at different pH) through columns. This was coupled with ultrafiltration in a range of molecular weight cut-off - 30, 10, 5 and 2kDalton - to distinguish between organically colloidal complexed metals and `free' metals. The Dissolved Organic Carbon (DOC) concentrations, the associated aromaticity were determined in the different fractions as well as the trace metal concentrations by ICP-MS. Ascending hierarchical classification was also performed to evidence DOC-trace element relationship. DOC distribution through time follows the same trend whichever was the pH. Three groups can be distinguished based on aromaticity and DOC data whichever can be the pH conditions. While K, Rb, Mg or Ca appear to behave as `free' ions, Th, U, REE, Fe or Al concentrations are correlated to DOC concentrations, suggesting that the organic colloidal pool dominates the carrying of these latter elements. Further studies dedicated to space- and time-linked variations of the joined colloidal pool and trace element distribution, will be then undertaken in waters recovered from different DOM-rich environments.

  20. Diclofenac Salts, VIII. Effect of the Counterions on the Permeation through Porcine Membrane from Aqueous Saturated Solutions

    Directory of Open Access Journals (Sweden)

    Cristina Cavallari

    2012-09-01

    Full Text Available The following bases: monoethylamine (EtA, diethylamine (DEtA, triethylamine (TEtA, monoethanolamine (MEA, diethanolamine (DEA, triethanolamine (TEA, pyrrolidine (Py, piperidine (Pp, morpholine (M, piperazine (Pz and their N-2-hydroxyethyl (HE analogs were employed to prepare 14 diclofenac salts. The salts were re-crystallized from water in order to obtain forms that are stable in the presence of water. Vertical Franz-type cells with a diffusional surface area of 9.62 cm2 were used to study the permeation of these diclofenac salts from their saturated solutions through an internal pig ear membrane. The receptor compartments of the cells contained 100 mL of phosphate buffer (pH 7.4; a saturated solution (5 mL of each salt was placed in the donor compartment, thermostated at 37 °C. Aliquots were withdrawn at predetermined time intervals over 8 h and then immediately analyzed by HPLC. Fluxes were determined by plotting the permeated amount, normalized for the membrane surface area versus time. Permeation coefficients were obtained dividing the flux values J by the concentration of the releasing phase—that is, water solubility of each salt. Experimental results show that fluxes could be measured when diclofenac salts with aliphatic amines are released from a saturated aqueous solution. Different chemical species (acid, anion, ion pairs contribute to permeation of the anti-inflammatory agent even though ion-pairs could be hypothesized to operate to a greater extent. Permeation coefficients were found higher when the counterion contains a ring; while hydroxy groups alone do not appear to play an important role, the ring could sustain permeation, disrupting the organized domains of the membrane.

  1. Distributed demand side management via smart appliances contributing to frequency control

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-chen

    2015-01-01

    Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is proposed to serve as a way that part of the regulation burden of balancing demand and supply is shifted to the demand side. However, if all appliances respond to the same frequency deviation, they may start to synchronize, causing large power overshoots and instability of the power grid. Therefore, the idea of implementing randomness into the frequency control of the appliances is proposed and this is what we call a stochastic approach. Simulators are built from scratch to model both scenarios. The effect of synchronization is analyzed and the parameters that can affect the synchronization are investigated. It has been found that the larger the contribution from the smart appliances to the power grid, the easier and faster the synchronization takes place. The stochastic approach solves the problem of synchronization and averages out the large power overshoot. However, the overall performance of stochastic operations is unacceptable due to the randomness in the operation though the mean and variance are as expected. More advanced feedback policies and schemes may be designed to achieve a better performance.

  2. Contributions to Desktop Grid Computing : From High Throughput Computing to Data-Intensive Sciences on Hybrid Distributed Computing Infrastructures

    OpenAIRE

    Fedak, Gilles

    2015-01-01

    Since the mid 90’s, Desktop Grid Computing - i.e the idea of using a large number of remote PCs distributed on the Internet to execute large parallel applications - has proved to be an efficient paradigm to provide a large computational power at the fraction of the cost of a dedicated computing infrastructure.This document presents my contributions over the last decade to broaden the scope of Desktop Grid Computing. My research has followed three different directions. The first direction has ...

  3. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage.

    Science.gov (United States)

    Mattsson, Brady J; Zipkin, Elise F; Gardner, Beth; Blank, Peter J; Sauer, John R; Royle, J Andrew

    2013-01-01

    Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  4. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage.

    Directory of Open Access Journals (Sweden)

    Brady J Mattsson

    Full Text Available Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  5. Size distributions of polycyclic aromatic hydrocarbons in urban atmosphere: sorption mechanism and source contributions to respiratory deposition

    Science.gov (United States)

    Lv, Yan; Li, Xiang; Xu, Ting Ting; Cheng, Tian Tao; Yang, Xin; Chen, Jian Min; Iinuma, Yoshiteru; Herrmann, Hartmut

    2016-03-01

    In order to better understand the particle size distribution of polycyclic aromatic hydrocarbons (PAHs) and their source contribution to human respiratory system, size-resolved PAHs have been studied in ambient aerosols at a megacity Shanghai site during a 1-year period (2012-2013). The results showed the PAHs had a bimodal distribution with one mode peak in the fine-particle size range (0.4-2.1 µm) and another mode peak in the coarse-particle size range (3.3-9.0 µm). Along with the increase in ring number of PAHs, the intensity of the fine-mode peak increased, while the coarse-mode peak decreased. Plotting of log(PAH / PM) against log(Dp) showed that all slope values were above -1, suggesting that multiple mechanisms (adsorption and absorption) controlled the particle size distribution of PAHs. The total deposition flux of PAHs in the respiratory tract was calculated as being 8.8 ± 2.0 ng h-1. The highest lifetime cancer risk (LCR) was estimated at 1.5 × 10-6, which exceeded the unit risk of 10-6. The LCR values presented here were mainly influenced by accumulation mode PAHs which came from biomass burning (24 %), coal combustion (25 %), and vehicular emission (27 %). The present study provides us with a mechanistic understanding of the particle size distribution of PAHs and their transport in the human respiratory system, which can help develop better source control strategies.

  6. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage

    Science.gov (United States)

    Mattsson, Brady J.; Zipkin, Elise F.; Gardner, Beth; Blank, Peter J.; Sauer, John R.; Royle, J. Andrew

    2013-01-01

    Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  7. Neither gastric topological distribution nor principle virulence genes of Helicobacterpylori contributes to clinical outcomes

    Institute of Scientific and Technical Information of China (English)

    Yan Wing Ho; Khek Yu Ho; Felipe Ascencio; Bow Ho

    2004-01-01

    AIM: Studies on Helicobacter pylori(Hpylori) and gastroduodenal diseases have focused mainly on the distal sites of the stomach, but relationship with the gastric cardia is lacking. The aim of this study is to determine if the gastric topology and genotypic distribution of H pylori were associated with different upper gastrointestinal pathologies in a multiethnic Asian population.METHODS: Gastric biopsies from the cardia, body/corpus and antrum were endoscoped from a total of 155 patients with dyspepsia and/or reflux symptoms, with informed consent. H pylori isolates obtained were tested for the presence of 26kDa, ureC, cagA, vacA, iceA1, iceA2 and babA2 genes using PCR while DNA fingerprints were generated using random amplification polymorphic DNA(RAPD).RESULTS: H pyloriwas present in 51/155 (33%) of patients studied. Of these, 16, 15 and 20 were isolated from patients with peptic ulcer diseases, gastroesophageal reflux diseases and non-ulcer dyspepsia, respectively. Of the H pylori positive patients, 75% (38/51) had H pylori in all three gastric sites.The prevalence of various genes in the H pylori isolates was shown to be similar irrespective of their colonization sites as well as among the same site of different patients.The RAPD profiles of H pylori isolates from different gastric sites were highly similar among intra-patients but varied greatly between different patients.CONCLUSION: Topographic colonization of H pylori and the virulence genes harboured by these isolates have no direct bearing to the clinical state of the patients. In multiethnic Singapore, the stomach of each patient is colonized by a predominant strain of H pylori, irrespective of the clinical diagnosis.

  8. Control Problems in Distribution Channels: Empirical Evidence of Management Control Systems Contributions.

    Directory of Open Access Journals (Sweden)

    José M. Sánchez Vázqez

    2006-12-01

    Full Text Available As part of the supply chain, manufacturing firms are increasingly placing greater emphasis on the management of their outsourced distribution channels (DCs. However, the role that interorganizational Management Control Systems (MCS can play in managing DC problems is still not clearly understood. Through an exploratory case study, we show how intra-organizational control problems persist in an inter-organizational context, rooted in informational asymmetries and conflicts of interest and aggravated by interdependencies. Likewise, the case study illustrates the way in which MCS assists the manufacturing firm to communicate to its representatives what the organization wants from them, motivating them and transferring capabilities. Thus, MCS can help to complement and re-orientate inter-firm agreements and constitutes a key tool for managing DCs in a flexible way.Como parte de la cadena de suministros, las empresas productoras están poniendo mayor énfasis en la gestión de sus canales de distribución externalizados (DCs. Sin embargo, aún no existe una clara comprensión sobre el papel que los Sistemas de Control de Gestión inter-organizativos (MCS pueden desarrollar en la gestión de los problemas de los DCs. A través de un estudio de caso, se muestra cómo los problemas de control intra-organizativos persisten en un contexto inter-organizativo, causados por las asimetrías informativas y el conflicto de intereses, y agravándose por las interdependencias. Asimismo, se expone cómo los MCS ayudan a la empresa productora a comunicar a sus distribuidores lo que la organización desea de ellos, motivándolos y capacitándolos. De esta forma, los MCS pueden ayudar a completar y redirigir acuerdos entre firmas y constituir una herramienta clave en la gestión flexible de los DCs.

  9. ISFET pH Sensitivity: Counter-Ions Play a Key Role

    Science.gov (United States)

    Parizi, Kokab B.; Xu, Xiaoqing; Pal, Ashish; Hu, Xiaolin; Wong, H. S. Philip

    2017-02-01

    The Field Effect sensors are broadly used for detecting various target analytes in chemical and biological solutions. We report the conditions under which the pH sensitivity of an Ion Sensitive Field Effect transistor (ISFET) sensor can be significantly enhanced. Our theory and simulations show that by using pH buffer solutions containing counter-ions that are beyond a specific size, the sensor shows significantly higher sensitivity which can exceed the Nernst limit. We validate the theory by measuring the pH response of an extended gate ISFET pH sensor. The consistency and reproducibility of the measurement results have been recorded in hysteresis free and stable operations. Different conditions have been tested to confirm the accuracy and validity of our experiment results such as using different solutions, various oxide dielectrics as the sensing layer and off-the-shelf versus IC fabricated transistors as the basis of the ISFET sensor.

  10. African and local wind-blown dist contributions at three rural sites in SE Spain: the aerosol size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Orza, J. A. G.; Cabello, M.; Lidon, V.; Martinez, J.

    2009-07-01

    The entrainment of particulate material into the atmosphere by wind action on surface soils both disturbed and natural, as well as directly due to human activities like agricultural practices, mineral industry operations, construction works and traffic, is a significant contribution to the aerosol load in Mediterranean semi-arid areas. A further crustal contribution in the region comes from the frequent arrival of African mineral dust plumes. We summarize some of the results obtained after 4-6 month campaigns at three rural sites in SE Spain where the aerosol number size distribution (31 size bins between 0.25 and 32 {mu}m) was continuously measured. The influence of both local wind speed and the arrival of air masses loaded with African dust on the airborne particulate distribution is assessed. Similarities and differences between the three locations give information that allows a better understanding of the influence of both local wind speed and African dust outbreaks (ADO), while highlight what is mostly related to local features. (Author)

  11. Time-resolved spectroscopy of the early photolysis intermediates of rhodopsin Schiff base counterion mutants.

    Science.gov (United States)

    Jäger, S; Lewis, J W; Zvyaga, T A; Szundi, I; Sakmar, T P; Kliger, D S

    1997-02-25

    Time-resolved absorption difference spectra of COS-cell expressed rhodopsin and rhodopsin mutants (E113D, E113A/A117E, and G90D), solubilized in detergent, were collected from 20 ns to 510 ms after laser photolysis with 7 ns pulses (lambda(max) = 477 nm). The data were analyzed using a global exponential fitting procedure following singular value decomposition (SVD). Over the entire time range excellent agreement was achieved between results for COS-cell and rod outer segment rhodopsin both in kinetics and in the lambda(max) values of the intermediates. The Schiff base counterion mutant E113D showed strong similarities to rhodopsin up to lumi, following the established scheme: batho bsi --> lumi. Including late delay times (past 1 micros), the mutant E113D lumi decayed to metarhodopsin II (MII), showing that the detergent strongly favors MII over metarhodopsin I (MI). However, a back-reaction from MII to lumi was observed that was not seen for rhodopsin. The kinetic schemes for the mutants E113A/A117E and G90D were significantly different from that of rhodopsin. In both mutants batho decay into an equilibrium with bsi was too fast to resolve ( lumi MI-like MII-like. However, the back-reaction from MI-like to lumi was not seen in G90D. MI-like spectral intermediates absorbing around 460 nm appeared in both mutants. They have been shown to be the transducin-activating species (R*). These data, interpreted in the context of previous NMR, FTIR, and Raman data, are consistent with a picture in which the kinetics of batho decay is dependent on a protein-induced perturbation near C12-C13 of the retinal chromophore. The lambda(max) values of the bsi and lumi intermediates in the mutant pigments are interpreted in terms of movement of the Schiff base relative to its counterion.

  12. Osmolality of antisense oligonucleotide parenteral formulations: Implications on counterion dissociation and recommended osmometry techniques.

    Science.gov (United States)

    Lim, Marc; Dibble, Andrew

    2016-12-30

    The intrinsic osmolality of aqueous solutions of sodium salt antisense oligonucleotides (ASOs) has been studied to inform formulation practices, understand the molecular basis underlying the difference between theoretical and empirical results, and determine suitable measurement methods. It was found that regardless of nucleotide sequence, ASO concentration of ∼140mg/mL has isotonic osmolality of ∼290mOsm/kg water (SI unit: mmol osmotically-active particles/kg water), such that lower concentration formulations require excipients for tonicity adjustment. The range of osmolality values at a given active ingredient concentration can be ascribed to drug substance lot-to-lot purity differences impacting total oligonucleotide content (i.e., including oligonucleotide-related impurities). Empirical osmolality measurements were found to be ∼70% of theoretical values, which corresponds to an osmotic coefficient value of ∼0.7, thus inferring incomplete counterion dissociation. When comparing theoretical (ideal) osmolality of multiple sequences with various nucleotide compositions and chemistries at the same w/v concentration, the "average osmolar mass" (molar mass of the oligonucleotide, including the sodium counterions, divided by the ideal Van't Hoff factor, i(id)) appears to be the strongest factor governing theoretical osmolality values. Other factors examined were the sequence length, backbone chemistry, 2' sugar chemistry, and nucleotide composition. A head-to-head comparison between two osmolality techniques showed that vapor pressure osmometry is generally more suitable than freezing point osmometry for oligonucleotide solutions greater than ∼150mg/mL due to viscosity effects, but the two techniques are comparable otherwise. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. The emerging source of polycyclic aromatic hydrocarbons from mining in the Tibetan Plateau: Distributions and contributions in background soils.

    Science.gov (United States)

    Li, Jun; Yuan, Guo-Li; Li, Ping; Sun, Yong; Yu, Hong-Hui; Wang, Gen-Hou

    2017-04-15

    The Tibetan Plateau (TP) serves as the background for persistent organic pollutants around the world. In addition to outside sources, local sources greatly contribute to the environment of the TP in recent decades. Mining activity could serve as an emerging source of polycyclic aromatic hydrocarbons (PAHs), although this issue has been neglected in the TP until now. To investigate the distributions and contributions of PAHs transported from mining activity, forty-one surface soil samples along six sampling directions were collected at a regular distance from the Jiama mining area (JMA) of the TP at altitudes between 3726 and 4863m. The total concentration of 16 PAHs was 52.34±22.58ng/g. The result of the source identification suggested that mining activity represented the primary source for heavy molecular weight (HMW) PAHs in soils, while light molecular weight (LMW) and middle molecular weight (MMW) PAHs were contributed by multiple sources. For HMW PAHs, the concentrations and proportions decreased logarithmically with transport distance from the JMA. Furthermore, the transport distance of HMW PAHs was found to be affected by the prevailing wind direction. In addition to transport from the source area, the distributions of LMW and MMW PAHs were also influenced by the altitude. In the impact area of Jiama mining activity, the soil mass inventory was estimated to be 6.4±0.8tons for HMW PAHs. In future decades, HMW PAHs emitted from Jiama mining activity are projected to exceed 5% of the annual local emission in the TP. Our study evidenced that Tibetan mining activity serves as an important emerging source of PAHs, which would be transported within the TP and threaten the fragile ecosystem of the TP.

  14. Spatial Distribution of the Cannabinoid Type 1 and Capsaicin Receptors May Contribute to the Complexity of Their Crosstalk

    Science.gov (United States)

    Chen, Jie; Varga, Angelika; Selvarajah, Srikumaran; Jenes, Agnes; Dienes, Beatrix; Sousa-Valente, Joao; Kulik, Akos; Veress, Gabor; Brain, Susan D.; Baker, David; Urban, Laszlo; Mackie, Ken; Nagy, Istvan

    2016-01-01

    The cannabinoid type 1 (CB1) receptor and the capsaicin receptor (TRPV1) exhibit co-expression and complex, but largely unknown, functional interactions in a sub-population of primary sensory neurons (PSN). We report that PSN co-expressing CB1 receptor and TRPV1 form two distinct sub-populations based on their pharmacological properties, which could be due to the distribution pattern of the two receptors. Pharmacologically, neurons respond either only to capsaicin (COR neurons) or to both capsaicin and the endogenous TRPV1 and CB1 receptor ligand anandamide (ACR neurons). Blocking or deleting the CB1 receptor only reduces both anandamide- and capsaicin-evoked responses in ACR neurons. Deleting the CB1 receptor also reduces the proportion of ACR neurons without any effect on the overall number of capsaicin-responding cells. Regarding the distribution pattern of the two receptors, neurons express CB1 and TRPV1 receptors either isolated in low densities or in close proximity with medium/high densities. We suggest that spatial distribution of the CB1 receptor and TRPV1 contributes to the complexity of their functional interaction. PMID:27653550

  15. Influence of a Counterion on the Ion Atmosphere of an Anion: A Molecular Dynamics Study of LiX and CsX (X = F(-), Cl(-), I(-)) in Methanol.

    Science.gov (United States)

    Kumar, Parveen; Kulkarni, Anant D; Yashonath, S

    2015-08-27

    We report molecular dynamics (MD) simulations to explore the influence of a counterion on the structure and dynamics of cationic and anionic solvation shells for various ions in methanol at 298 K. We show that the variation in ionic size of either the cation or the anion in an ion pair influences the solvation structure of the other ion as well as the diffusivity in an electrolyte solution of methanol. The extent of ionic association between the cation and its counteranion of different ionic sizes has been investigated by analyzing the radial distribution functions (RDFs) and the orientation of methanol molecules in the first solvation shell (FSS) of ions. It is shown that the methanol in the FSS of the anion as well the cation exhibit quite different radial and orientational structures as compared to methanol which lie in the FSS of either the anion or the cation but not both. We find that the coordination number (CN) of F(-), Cl(-), and I(-) ions decreases with increasing size of the anion which is contrary to the trend reported for the anions in H2O. The mean residence time (MRT) of methanol molecules in the FSS of ions has been calculated using the stable states picture (SSP) approach. It is seen that the ion-counterion interaction has a considerable influence on the MRT of methanol molecules in the FSS of ions. We also discuss the stability order of the ion-counterion using the potentials of mean force (PMFs) for ion pairs with ions of different sizes. The PMF plots reveal that the Li(+)-F(-) pair (small-small) is highly stable and the Li(+)-I(-) pair is least stable (small-large) in electrolyte solutions.

  16. Contribution and distribution of inorganic ions and organic compounds to the osmotic adjustment in Halostachys caspica response to salt stress.

    Science.gov (United States)

    Zeng, Youling; Li, Ling; Yang, Ruirui; Yi, Xiaoya; Zhang, Baohong

    2015-09-09

    The mechanism by which plants cope with salt stress remains poorly understood. The goal of this study is to systematically investigate the contribution and distribution of inorganic ions and organic compounds to the osmotic adjustment (OA) in the halophyte species Halostachys caspica. The results indicate that 100-200 mM NaCl is optimal for plant growth; the water content and degree of succulence of the assimilating branches are higher in this treatment range than that in other treatments; parenchyma cells are more numerous with 100 mM NaCl treatment than they are in control. Inorganic ions (mainly Na+ and Cl-) may play a more important role than organic compounds in NaCl-induced OA and are the primary contributors in OA in H. caspica. The inorganic ions and organic solutes display a tissue-dependent distribution. Na+ and Cl- are accumulated in the reproductive organs and within assimilating branches, which may represent a mechanism for protecting plant growth by way of salt ion dilution and organ abscission. Additionally, OA via increased accumulation of organic substances also protected plant growth and development. This finding provides additional evidence for plant tolerance to salinity stress which can be used for breeding new cultivars for stress tolerance.

  17. Multivalent co-ions reduce DNA$-$DNA like-charge attraction and enhance DNA overcharging by mutivalent counterions

    CERN Document Server

    Duc, Nguyen Viet; Duc, Nguyen Huu

    2016-01-01

    Strongly correlated electrostatics of DNA systems has drawn the interest of many groups, especially the condensation and overcharging of DNA by multivalent counterions. By adding counterions of different valencies and shapes, one can enhance or reduce DNA overcharging. In this letter, we focus on the effect of multivalent co-ions, specifically divalent coion such as SO$_4^{2-}$, on the strongly correlated electrostatics of DNA condensation problem. A computational experiment of DNA condensation using Monte$-$Carlo simulation in grand canonical ensemble is carried out where DNA system is in equilibirium with a bulk solution containing a mixture of salt of different valency of co-ions. Compared to system with purely monovalent co-ions, the influence of divalent co-ions shows up in multiple aspects. Divalent co-ions lead to an increase of monovalent salt in the DNA condensate. Because monovalent salts mostly participate in linear screening of electrostatic interactions in the system, more monovalent salt molecul...

  18. Role of counterion condensation in the self-assembly of SDS surfactants at the water-graphite interface.

    Science.gov (United States)

    Tummala, Naga Rajesh; Striolo, Alberto

    2008-02-21

    The aggregate structure of sodium dodecyl sulfate (SDS) adsorbed at the graphite-water interface has been studied with the aid of molecular dynamics (MD) simulations. As expected, our results show that adsorbed SDS yields hemi-cylindrical micelles. The hemi-cylindrical aggregates in our simulations closely resemble all structural and morphological details provided by previous solution atomic force microscopy (AFM) experiments. More interestingly, our data indicate that SDS head groups do not provide a complete shield to the hydrophobic tails. Instead, we found regions in which the hydrophobic tails are exposed to the aqueous solution. By conducting a parametric study for SDS-like nonionic surfactants we show that electrostatic interactions between SDS head groups and counterions are responsible for the unexpected result. Our interpretation is corroborated by density profiles, analysis of the coordination states, and mean square displacement data for both the adsorbed SDS surfactants and the counterions in solution. Counterion condensation appears to be a physical phenomenon that could be exploited to direct the assembly of advanced nanostructured materials.

  19. Interactions of human hemoglobin with charged ligand-functionalized iron oxide nanoparticles and effect of counterions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Goutam, E-mail: ghoshg@yahoo.com [UGC-DAE Consortium for Scientific Research, Mumbai Centre (India); Panicker, Lata [Bhabha Atomic Research Centre, Solid State Physics Division (India)

    2014-12-15

    Human hemoglobin is an important metalloprotein. It has tetrameric structure with each subunit containing a ‘heme’ group which carries oxygen and carbon dioxide in blood. In this work, we have investigated the interactions of human hemoglobin (Hb) with charged ligand-functionalized iron oxide nanoparticles and the effect of counterions, in aqueous medium. Several techniques like DLS and ζ-potential measurements, UV–vis, fluorescence, and CD spectroscopy have been used to characterize the interaction. The nanoparticle size was measured to be in the range of 20–30 nm. Our results indicated the binding of Hb with both positively as well as negatively charged ligand-functionalized iron oxide nanoparticles in neutral aqueous medium which was driven by the electrostatic and the hydrophobic interactions. The electrostatic binding interaction was not seen in phosphate buffer at pH 7.4. We have also observed that the ‘heme’ groups of Hb remained unaffected on binding with charged nanoparticles, suggesting the utility of the charged ligand-functionalized nanoparticles in biomedical applications.

  20. Excessive Counterion Condensation on Immobilized ssDNA in Solutions of High Ionic Strength

    Science.gov (United States)

    Rant, Ulrich; Arinaga, Kenji; Fujiwara, Tsuyoshi; Fujita, Shozo; Tornow, Marc; Yokoyama, Naoki; Abstreiter, Gerhard

    2003-01-01

    We present experiments on the bias-induced release of immobilized, single-stranded (ss) 24-mer oligonucleotides from Au-surfaces into electrolyte solutions of varying ionic strength. Desorption is evidenced by fluorescence measurements of dye-labeled ssDNA. Electrostatic interactions between adsorbed ssDNA and the Au-surface are investigated with respect to 1), a variation of the bias potential applied to the Au-electrode; and 2), the screening effect of the electrolyte solution. For the latter, the concentration of monovalent salt in solution is varied from 3 to 1600 mM. We find that the strength of electric interaction is predominantly determined by the effective charge of the ssDNA itself and that the release of DNA mainly occurs before the electrochemical double layer has been established at the electrolyte/Au interface. In agreement with Manning's condensation theory, the measured desorption efficiency (ηrel) stays constant over a wide range of salt concentrations; however, as the Debye length is reduced below a value comparable to the axial charge spacing of the DNA, ηrel decreases substantially. We assign this effect to excessive counterion condensation on the DNA in solutions of high ionic strength. In addition, the relative translational diffusion coefficient of ssDNA in solution is evaluated for different salt concentrations. PMID:14645075

  1. Counter-ion dynamics in crosslinked poly(styrene sulfonate) systems studied by NMR.

    Science.gov (United States)

    Tromp, R H; van der Maarel, J R; de Bleijser, J; Leyte, J C

    1991-10-01

    The field dependence of the longitudinal and transverse nuclear magnetic relaxation rates of 23Na+ in aqueous crosslinked Na-poly(styrene sulfonate) (PSS) systems (ion exchange resins) has been obtained as a function of the degree of crosslinking. The relaxation is considerably enhanced relative to solutions of non-crosslinked NaPSS at equal ionizable group concentration. This is due to the dynamic constraints of the polymer chains, which render the averaging of the counter-ion chain interaction less efficient. The field dependence of the relaxation rates in the crosslinked NaPSS systems reveals two processes that are out of the extreme narrowing limit. This is in contrast to the relaxation behavior found in non-crosslinked NaPSS systems. To characterize these processes their correlation times were combined with constants of selfdiffusion to estimate the distances diffused by an ion in order to average the electric field gradient at its nucleus. These two distances are interpreted as characteristic length scales in the network. At all degrees of crosslinking it was found that the smallest of these length scales is roughly equal to the distance between two neighbouring crosslinks. The largest characteristic distance extends over several crosslinks and reflects inhomogeneities in the crosslink concentration. These conclusions were also reached from similar experiments on 7Li+ in LiPSS systems.

  2. Effects of solute-solute interactions on protein stability studied using various counterions and dendrimers.

    Directory of Open Access Journals (Sweden)

    Curtiss P Schneider

    Full Text Available Much work has been performed on understanding the effects of additives on protein thermodynamics and degradation kinetics, in particular addressing the Hofmeister series and other broad empirical phenomena. Little attention, however, has been paid to the effect of additive-additive interactions on proteins. Our group and others have recently shown that such interactions can actually govern protein events, such as aggregation. Here we use dendrimers, which have the advantage that both size and surface chemical groups can be changed and therein studied independently. Dendrimers are a relatively new and broad class of materials which have been demonstrated useful in biological and therapeutic applications, such as drug delivery, perturbing amyloid formation, etc. Guanidinium modified dendrimers pose an interesting case given that guanidinium can form multiple attractive hydrogen bonds with either a protein surface or other components in solution, such as hydrogen bond accepting counterions. Here we present a study which shows that the behavior of such macromolecule species (modified PAMAM dendrimers is governed by intra-solvent interactions. Attractive guanidinium-anion interactions seem to cause clustering in solution, which inhibits cooperative binding to the protein surface but at the same time, significantly suppresses nonnative aggregation.

  3. A novel protein quality control mechanism contributes to heat shock resistance of worldwide-distributed Pseudomonas aeruginosa clone C strains.

    Science.gov (United States)

    Lee, Changhan; Wigren, Edvard; Trček, Janja; Peters, Verena; Kim, Jihong; Hasni, Muhammad Sharif; Nimtz, Manfred; Lindqvist, Ylva; Park, Chankyu; Curth, Ute; Lünsdorf, Heinrich; Römling, Ute

    2015-11-01

    Pseudomonas aeruginosa is a highly successful nosocomial pathogen capable of causing a wide variety of infections with clone C strains most prevalent worldwide. In this study, we initially characterize a molecular mechanism of survival unique to clone C strains. We identified a P. aeruginosa clone C-specific genomic island (PACGI-1) that contains the highly expressed small heat shock protein sHsp20c, the founding member of a novel subclass of class B bacterial small heat shock proteins. sHsp20c and adjacent gene products are involved in resistance against heat shock. Heat stable sHsp20c is unconventionally expressed in stationary phase in a wide temperature range from 20 to 42°C. Purified sHsp20c has characteristic features of small heat shock protein class B as it is monodisperse, forms sphere-like 24-meric oligomers and exhibits significant chaperone activity. As the P. aeruginosa clone C population is significantly more heat shock resistant than genetically unrelated P. aeruginosa strains without sHsp20c, the horizontally acquired shsp20c operon might contribute to the survival of worldwide-distributed clone C strains.

  4. Electrochemical charging of CdSe quantum dot films: dependence on void size and counterion proximity.

    Science.gov (United States)

    Boehme, Simon C; Wang, Hai; Siebbeles, Laurens D A; Vanmaekelbergh, Daniel; Houtepen, Arjan J

    2013-03-26

    Films of colloidal quantum dots (QDs) show great promise for application in optoelectronic devices. Great advances have been made in recent years in designing efficient QD solar cells and LEDs. A very important aspect in the design of devices based on QD films is the knowledge of their absolute energy levels. Unfortunately, reported energy levels vary markedly depending on the employed measurement technique and the environment of the sample. In this report, we determine absolute energy levels of QD films by electrochemical charge injection. The concomitant change in optical absorption of the film allows quantification of the number of charges in quantum-confined levels and thereby their energetic position. We show here that the size of voids in the QD films (i.e., the space between the quantum dots) determines the amount of charges that may be injected into the films. This effect is attributed to size exclusion of countercharges from the electrolyte solution. Further, the energy of the QD levels depends on subtle changes in the QD film and the supporting electrolyte: the size of the cation and the QD ligand length. These nontrivial effects can be explained by the proximity of the cation to the QD surface and a concomitant lowering of the electrochemical potential. Our findings help explain the wide range of reported values for QD energy levels and redefine the limit of applicability of electrochemical measurements on QD films. Finally, the finding that the energy of QD levels depends on ligand length and counterion size may be exploited in optimized designs of QD sensitized solar cells.

  5. Counterion effects on fluorescence energy transfer in conjugated polyelectrolyte-based DNA detection.

    Science.gov (United States)

    Nag, Okhil Kumar; Kang, Mijeong; Hwang, Sungu; Suh, Hongsuk; Woo, Han Young

    2009-04-30

    Cationic poly[9,9'-bis[6''-(N,N,N-trimethylammonium)hexyl]fluorene-co-alt-phenylene]s with five different counterions (CIs) were synthesized and studied as fluorescence resonance energy transfer (FRET) donors (D) to dye-labeled DNA (FRET acceptor, A). The polymers with different CIs show the same pi-conjugated electronic structure with similar absorption (lambda(abs) = approximately 380 nm) and photoluminescence (lambda(PL) = approximately 420 nm) emission spectra in water. The CIs accompanying the polymer chain are expected to affect the D/A complexation and modify the D-A intermolecular separation by acting as a spacer. Polymers with different CIs function differently as FRET excitation donors to fluorescein (Fl)-labeled single-stranded DNA (ssDNA-Fl). The FRET-induced Fl emission was enhanced significantly by the larger CI-exchanged polymers. The polymers with the CIs of tetrakis(1-imidazolyl)borate (FPQ-IB) and tetraphenylborate (FPQ-PB) showed a 2-4-fold enhancement in the FRET-induced signal compared with the polymer with bromide (FPQ-BR). The delayed FRET signal saturation and low association constants (K(a)) with ssDNA-Fl (3.53 x 10(6) M(-1) for FPQ-BR and 1.80 x 10(6) M(-1) for FPQ-PB) were measured for the polymers with larger CIs. The delayed acceptor saturation strengthens the antenna effect and reduces self-quenching of Fl by increasing the polymer concentration near Fl. The weak polymer/ssDNA-Fl association reduces the amount of energy-wasting charge transfer by increasing D-A intermolecular separation. The combined effects lead to increase the overall FRET-induced signal.

  6. Contribution of land use to rodent flea load distribution in the plague endemic area of Lushoto District, Tanzania.

    Science.gov (United States)

    Hieronimo, Proches; Kihupi, Nganga I; Kimaro, Didas N; Gulinck, Hubert; Mulungu, Loth S; Msanya, Balthazar M; Leirs, Herwig; Deckers, Jozef A

    2014-07-01

    Fleas associated with different rodent species are considered as the major vectors of bubonic plague, which is still rampant in different parts of the world. The objective of this study was to investigate the contribution of land use to rodent flea load distribution at fine scale in the plague endemic area of north-eastern Tanzania. Data was collected in three case areas namely, Shume, Lukozi and Mwangoi, differing in plague incidence levels. Data collection was carried out during both wet and dry seasons of 2012. Analysis of Variance and Boosted Regression Tree (BRT) statistical methods were used to clarify the relationships between fleas and specific land use characteristics. There was a significant variation (P ≤ 0.05) of flea indices in different land use types. Fallow and natural forest had higher flea indices whereas plantation forest mono-crop and mixed annual crops had the lowest flea indices among the aggregated land use types. The influence of individual land use types on flea indices was variable with fallow having a positive effect and land tillage showing a negative effect. The results also demonstrated a seasonal effect, part of which can be attributed to different land use practices such as application of pesticides, or the presence of grass strips around fields. These findings suggest that land use factors have a major influence on rodent flea abundance which can be taken as a proxy for plague infection risk. The results further point to the need for a comprehensive package that includes land tillage and crop type considerations on one hand and the associated human activities on the other, in planning and implementation of plague control interventions.

  7. Multiplicity distribution of final-state particles and different contributions of related Sources in nucleus-nucleus collisions at high energies

    Institute of Scientific and Technical Information of China (English)

    SUN Zhu; LIU Pu-Hu

    2008-01-01

    The final state particle multiplicity distributions in high-energy nucleus-nucleus collisions are described by two different sub-distributious contributed by a single nucleon.The Monte Carlo calculated results from the two sub-distributions and the participant-spectator model are compared and found to be in agreement with the experimental data of Au-Au collisions ats=130 AGeV and Pb-Pb collisions at 158 AGeV.

  8. On the correction of calculated vibrational frequencies for the effects of the counterions - α,ω-diamine dihydrochlorides.

    Science.gov (United States)

    Fiuza, S M; Silva, T M; Marques, M P M; de Carvalho, L A E Batista; Amado, A M

    2015-10-01

    The present work provides sets of correction factors to adjust the calculated vibrational frequencies of a series of α,ω-diamines hydrochloride salts to account for the intermolecular interactions with the counterion. The study was performed using different theory levels for predicting the vibrational data of isolated dicationic α,ω-diamines and their hydrochloride forms, with and without the explicit account of the interactions with the chloride counterions. Different sets of correction factors were determined for each theory level considering the four smallest elements for the α,ω-diamines series, while their transferability and reliability was evaluated considering the larger elements of the series. The theory level simplification was also evaluated and was found to neither compromise the vibrational frequencies estimates nor the magnitude and accuracy of the pre-defined scaling factors. This suggests that transferability of the correction factors is possible not only for different diamines but also between different levels of theory with the averaged group correction factor, ζ g (a) , being the best choice to account for the effects of the N-H · · · Cl interactions. The possibility of simplifying the theory level without compromising efficiency and accuracy is additionally of utmost importance. This computational approach can constitute a valuable tool in the future for studying the hydrochloride forms of larger and more complex diamine systems. Graphical Abstract A computational approach that may constitute a valuable tool for studying the hydrochloride forms of large and complex diamine systems. Correction factors to adjust the vibrational frequencies calculated for isolated dicationic primary diamines for the effects of the interactions with chloride counterions, without their explicit account in the calculations, are presented and evaluated for eficiency.

  9. Effects of counterion valency on the damping of phonons propagating along the axial direction of liquid-crystalline DNA

    Science.gov (United States)

    Liu, Yun; Chen, Sow-Hsin; Berti, Debora; Baglioni, Piero; Alatas, Ahmet; Sinn, Harald; Alp, Ercan; Said, Ayman

    2005-12-01

    The phonon propagation and damping along the axial direction of films of aligned 40wt% calf-thymus DNA rods are studied by inelastic x-ray scattering (IXS). The IXS spectra are analyzed with the generalized three effective eigenmode theory, from which we extract the dynamic structure factor S (Q,E) as a function of transferred energy E =ℏω, and the magnitude of the transferred wave vector Q. S (Q,E) of a DNA sample typically consists of three peaks, one central Rayleigh scattering peak, and two symmetric Stokes and anti-Stokes Brillouin side peaks. By analyzing the Brillouin peaks, the phonon excitation energy and damping can be extracted at different Q values from about 4 to 30nm-1. A high-frequency sound speed is obtained from the initial slope of the linear portion of the dispersion relation below Q =4nm-1. The high-frequency sound speed obtained in this Q range is 3100m /s, which is about twice faster than the ultrasound speed of 1800m/s, measured by Brillouin light scattering at Q ˜0.01nm-1 at the similar hydration level. Our observations provide further evidence of the strong coupling between the internal dynamics of a DNA molecule and the dynamics of the solvent. The effect on damping and propagation of phonons along the axial direction of DNA rods due to divalent and trivalent counterions has been studied. It is found that the added multivalent counterions introduce stronger phonon damping. The phonons at the range between ˜12.5 and ˜22.5nm-1 are overdamped by the added counterions according to our model analyses. The intermediate scattering function is extracted and it shows a clear two-step relaxation with the fast relaxation time ranging from 0.1 to 4ps.

  10. Insecticidal genes of Yersinia spp.: taxonomical distribution, contribution to toxicity towards Manduca sexta and Galleria mellonella, and evolution

    Directory of Open Access Journals (Sweden)

    Schachtner Joachim

    2008-12-01

    Full Text Available Abstract Background Toxin complex (Tc proteins termed TcaABC, TcdAB, and TccABC with insecticidal activity are present in a variety of bacteria including the yersiniae. Results The tc gene sequences of thirteen Yersinia strains were compared, revealing a high degree of gene order conservation, but also remarkable differences with respect to pseudogenes, sequence variability and gene duplications. Outside the tc pathogenicity island (tc-PAIYe of Y. enterocolitica strain W22703, a pseudogene (tccC2'/3' encoding proteins with homology to TccC and similarity to tyrosine phosphatases at its C-terminus was identified. PCR analysis revealed the presence of the tc-PAIYe and of tccC2'/3'-homologues in all biotype 2–5 strains tested, and their absence in most representatives of biotypes 1A and 1B. Phylogenetic analysis of 39 TccC sequences indicates the presence of the tc-PAIYe in an ancestor of Yersinia. Oral uptake experiments with Manduca sexta revealed a higher larvae lethality of Yersinia strains harbouring the tc-PAIYe in comparison to strains lacking this island. Following subcutaneous infection of Galleria mellonella larvae with five non-human pathogenic Yersinia spp. and four Y. enterocolitica strains, we observed a remarkable variability of their insecticidal activity ranging from 20% (Y. kristensenii to 90% (Y. enterocolitica strain 2594 dead larvae after five days. Strain W22703 and its tcaA deletion mutant did not exhibit a significantly different toxicity towards G. mellonella. These data confirm a role of TcaA upon oral uptake only, and suggest the presence of further insecticidal determinants in Yersinia strains formerly unknown to kill insects. Conclusion This study investigated the tc gene distribution among yersiniae and the phylogenetic relationship between TccC proteins, thus contributing novel aspects to the current discussion about the evolution of insecticidal toxins in the genus Yersinia. The toxic potential of several Yersinia

  11. Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and their contribution to primary production

    Directory of Open Access Journals (Sweden)

    J.-P. Gattuso

    2006-01-01

    Full Text Available One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface (S of the coastal zone receiving an irradiance greater than Ez (in mol photons m−2 d−1: SNon-polar = 29.61 − 17.92 log10(Ez + 0.72 log102(Ez + 0.90 log103(Ez SArctic = 15.99 − 13.56 log10(Ez + 1.49 log102(Ez + 0.70 log103(Ez Data on the constraint of light availability on the major benthic primary producers and net community production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m. The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1 light does not limit the distribution of primary producers and (2 net community production (NCP, the balance between gross primary production and community respiration is positive. Positive benthic NCP can occur over 33% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, the lack of global information on the benthic

  12. Non-uniform velocity of homogeneous DNA in a uniform electric field: consequence of electric-field-induced slow dissociation of highly stable DNA-counterion complexes.

    Science.gov (United States)

    Musheev, Michael U; Kanoatov, Mirzo; Krylov, Sergey N

    2013-05-29

    Identical molecules move with identical velocities when placed in a uniform electric field within a uniform electrolyte. Here we report that homogeneous DNA does not obey this fundamental rule. While most DNA moves with similar velocities, a fraction of DNA moves with velocities that vary within a multiple-fold range. The size of this irregular fraction increases several orders of magnitude when exogenous counterions are added to DNA. The irregular fraction decreases several orders of magnitude when DNA counterions are removed by dialysis against deionized water in the presence of a strong electric field (0.6 kV/cm). Dialysis without the field is ineffective in decreasing the size of irregular fraction. These results suggest that (i) DNA can form very stable complexes with counterions, (ii) these complexes can be dissociated by an electric field, and (iii) the observed non-uniform velocity of DNA is caused by electric-field-induced slow dissociation of these stable complexes. Our findings help to better understand a fundamental property of DNA: its interaction with counterions. In addition, these findings suggest a practical way of making electromigration of DNA more uniform: removal of strongly bound DNA counterions by electro-dialysis against deionized water.

  13. NUMERICAL ANALYSIS OF MATHEMATICAL MODELS OF THE FACTUAL CONTRIBUTION DISTRIBUTION IN ASYMMETRY AND DEVIATION OF VOLTAGE AT THE COMMON COUPLING POINTS OF ENERGY SUPPLY SYSTEMS

    Directory of Open Access Journals (Sweden)

    Yu.L. Sayenko

    2016-05-01

    Full Text Available Purpose. Perform numerical analysis of the distribution of the factual contributions of line sources of distortion in the voltage distortion at the point of common coupling, based on the principles of superposition and exclusions. Methodology. Numerical analysis was performed on the results of the simulation steady state operation of power supply system of seven electricity consumers. Results. Mathematical model for determining the factual contribution of line sources of distortion in the voltage distortion at the point of common coupling, based on the principles of superposition and exclusions, are equivalent. To assess the degree of participation of each source of distortion in the voltage distortion at the point of common coupling and distribution of financial compensation to the injured party by all sources of distortion developed a one-dimensional criteria based on the scalar product of vectors. Not accounting group sources of distortion, which belong to the subject of the energy market, to determine their total factual contribution as the residual of the factual contribution between all sources of distortion. Originality. Simulation mode power supply system was carried out in the phase components space, taking into account the distributed characteristics of distortion sources. Practical value. The results of research can be used to develop methods and tools for distributed measurement and analytical systems assessment of the power quality.

  14. The model of a polyelectrolyte solution with explicit account of counterions within a self-consistent field theory

    Science.gov (United States)

    Budkov, Yu. A.; Nogovitsyn, E. A.; Kiselev, M. G.

    2013-04-01

    A theoretical approach to calculating the thermodynamic and structural functions of solutions of polyelectrolytes based on Gaussian equivalent representation for the calculation of functional integrals is proposed. It is noted that a new analytical result of this work is the direct assumption of counterions, along with an equation for the gyration radius of a polymer chain as a function of the concentrations of monomers and added low-molecular salt. An equation of state is obtained within the proposed model. Our theoretical results are used to describe the thermodynamic and structural properties of an aqueous solution of sodium polystyrene sulfonate with additions of NaCl.

  15. Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and contribution to primary production

    Directory of Open Access Journals (Sweden)

    J.-P. Gattuso

    2006-07-01

    Full Text Available One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface of the coastal zone receiving an irradiance greater than Ez:

    PaNon-polar=28.80−16.69 log10(Ez+0.84 log102(Ez+0.83 log103(Ez


    PaArctic=16.01−15.67 log10(Ez+2.03 log102(Ez+1.00 log103(Ez

    Data on the constraint of light availability on the major benthic primary producers and net primary production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m. The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where

  16. Antimicrobial polymers prepared by ring-opening metathesis polymerization: manipulating antimicrobial properties by organic counterion and charge density variation.

    Science.gov (United States)

    Lienkamp, Karen; Madkour, Ahmad E; Kumar, Kushi-Nidhi; Nüsslein, Klaus; Tew, Gregory N

    2009-11-02

    The synthesis and characterization of a series of poly(oxanorbornene)-based synthetic mimics of antimicrobial peptides (SMAMPs) is presented. In the first part, the effect of different organic counterions on the antimicrobial properties of the SMAMPs was investigated. Unexpectedly, adding hydrophobicity by complete anion exchange did not increase the SMAMPs' antimicrobial activity. It was found by dye-leakage studies that this was due to the loss of membrane activity of these polymers caused by the formation of tight ion pairs between the organic counterions and the polymer backbone. In the second part, the effect of molecular charge density on the biological properties of a SMAMP was investigated. The results suggest that, above a certain charge threshold, neither minimum inhibitory concentration (MIC90) nor hemolytic activity (HC50) is greatly affected by adding more cationic groups to the molecule. A SMAMP with an MIC90 of 4 microg mL(-1) against Staphylococcus aureus and a selectivity (=HC50/MIC90) of 650 was discovered, the most selective SMAMP to date.

  17. pH-dependent absorption spectra of rhodopsin mutant E113Q: On the role of counterions and protein

    Science.gov (United States)

    Xie, Peng; Zhou, Panwang; Alsaedi, Ahmed; Zhang, Yan

    2017-03-01

    The absorption spectra of bovine rhodopsin mutant E113Q in solutions were investigated at the molecular level by using a hybrid quantum mechanics/molecular mechanics (QM/MM) method. The calculations suggest the mechanism of the absorption variations of E113Q at different pH values. The results indicate that the polarizations of the counterions in the vicinity of Schiff base under protonation and unprotonation states of the mutant E113Q would be a crucial factor to change the energy gap of the retinal to tune the absorption spectra. Glu-181 residue, which is close to the chromophore, cannot serve as the counterion of the protonated Schiff base of E113Q in dark state. Moreover, the results of the absorption maximum in mutant E113Q with the various anions (Cl-, Br-, I- and NO3-) manifested that the mutant E113Q could have the potential for use as a template of anion biosensors at visible wavelength.

  18. The effects of counterion composition on the rheological and conductive properties of mono- and diphosphonium ionic liquids.

    Science.gov (United States)

    Yonekura, Reimi; Grinstaff, Mark W

    2014-10-14

    A series of monocationic and dicationic phosphonium ionic liquids was prepared and their thermal, rheological, and conductive properties were characterized. These phosphonium ionic liquids were paired with seven monoanionic counterions (chloride, hexafluorophosphate, hexafluoroantimonate, octanoate, perfluorooctanoate, dodecyl sulfate, dioctyl sulfosuccinate, and bis(trifluoromethane)sulfonimide) in order to examine the effects of the counterion size and chemical structure on bulk properties of the phosphonium ionic liquids. The length of the three alkyl chains surrounding the phosphorus atom was also varied from butyl, hexyl to octyl on the cation. All of the samples exhibited initial decomposition temperatures above 150 °C. The octanoate and its fluorinated analog possessed the lowest decomposition temperature and the dicationic hexyl sample bis(trifluoromethane)sulfonimide possessed the highest (>370 °C). The dicationic butyl and hexyl chloride samples displayed similar G', G″ and viscosity curves, whereas the dicationic octyl chloride sample exhibited significantly lower values. The frequency sweeps of the monocationic phosphonium ionic liquids were all similar and showed minimal side chain dependence. The monocationic phosphonium ionic liquids have higher conductivity than their dicationic analogs at all measured temperatures.

  19. Coordination of foliar and wood anatomical traits contributes to tropical tree distributions and productivity along the Malay-Thai Peninsula.

    Science.gov (United States)

    Baltzer, Jennifer L; Grégoire, Dorthea M; Bunyavejchewin, Sarayudh; Noor, N Supardi M; Davies, Stuart J

    2009-12-01

    Drought is a critical factor in plant species distributions. Much research points to its relevance even in moist tropical regions. Recent studies have begun to elucidate mechanisms underlying the distributions of tropical tree species with respect to drought; however, how such desiccation tolerance mechanisms correspond with the coordination of hydraulic and photosynthetic traits in determining species distributions with respect to rainfall seasonality deserves attention. In the present study, we used a common garden approach to quantify inherent differences in wood anatomical and foliar physiological traits in 21 tropical tree species with either widespread (occupying both seasonal and aseasonal climates) or southern (restricted to aseasonal forests) distributions with respect to rainfall seasonality. Use of congeneric species pairs and phylogenetically independent contrast analyses allowed examination of this question in a phylogenetic framework. Widespread species opted for wood traits that provide biomechanical support and prevent xylem cavitation and showed associated reductions in canopy productivity and consequently growth rates compared with southern species. These data support the hypothesis that species having broader distributions with respect to climatic variability will be characterized by traits conducive to abiotic stress tolerance. This study highlights the importance of the well-established performance vs. stress tolerance trade-off as a contributor to species distributions at larger scales.

  20. Value Engineering in System of Cryoline and Cryo- distribution for ITER: In-kind Contribution from India

    Science.gov (United States)

    Sarkar, B.; Shah, N.; Vaghela, H.; Bhattacharya, R.; Choukekar, K.; Patel, P.; Chang, H.-S.; Badgujar, S.; Chalifour, M.

    2015-12-01

    System of Cryoline and Cryo-distribution for ITER has matured to a stage of preliminary design with the advent of industrial associates. Starting from the cold power source, the system of Cryoline and Cryo-distribution transfers the controlled cold power through a large network to the superconducting magnets and cryopumps. The functional responsibility also includes very high reliability and availability with respect to the operation of the ITER machine. Following the completion of conceptual design, it was necessary to perform a detailed engineering study of the complete network of distribution system in totality, before entering in to the industrial phase. This is to ensure the functional responsibility of the system. Value engineering in the area of distribution boxes including interfacing Cryolines has been performed in order to access the integrated reliable performance with respect to the overall cryogenic system, reducing the risk transferred to the industrial partners. These include technical risk assessment, analysis, mitigation plan and implementation with the industrial partners. The paper describes the methodology of technical risk management, value engineering performed to ensure fulfilment of licensing and regulatory obligations, functional reliability, testing and manufacturability by standard industrial processes, so that highly reliable integrated distribution system is delivered for the project.

  1. CONTRIBUTIONS TO THE STUDY OF HEAVY METALS DISTRIBUTION (Zn, Pb, Cd, Bi, Cu IN SOME SOILS FROM GIURGEU MOUNTAINS

    Directory of Open Access Journals (Sweden)

    D. Bulgariu

    2005-10-01

    Full Text Available In this paper are presented the results of mineralogical and geochemical studies, realized for few soils from Giurgeu Mountains, which have as main purpose the distribution and mobility interpretation of minor elements (Cd, Cu, Pb, Zn, Bi in studied soil samples. The determination of fixed fractions and mobile fractions weight, at total contents of studied elements, and relative association of these elements with main mineral and organic components of soil samples, was realized on the basis of results obtained by sequential solid/ liquid extraction. The same, we try to use the correlation establish between metallic ions contents, as indicators of mineral paragenesis (the genetic type and formation conditions. The obtained results are agree with the results of similar studies from literature and they, underline of some interesting aspects about of distribution and migration of heavy metals in soils: (1 exist of some selectivity in heavy metals distribution in mineral components from soils, correlated with reciprocals geochemical affinities between speciation forms of metals and mineral components, in a given pedogeochemical context; (2 the heavy metals distribution between solid phases and soil solution are realized in competitive regime, and the inter-phases equilibrium evolution are thermodynamic and kinetics controlled by the solid/ liquid interfaces processes; (3 the fast elementary processes and local fluctuations of physic-chemical parameters are the main factors which controlled the inter-phases transfer ratio and the evolution direction of equilibriums of heavy metals distribution.

  2. Diketonylpyridinium Cations as a Support of New Ionic Liquid Crystals and Ion-Conductive Materials: Analysis of Counter-Ion Effects

    Science.gov (United States)

    Pastor, María Jesús; Cuerva, Cristián; Campo, José A.; Schmidt, Rainer; Torres, María Rosario; Cano, Mercedes

    2016-01-01

    Ionic liquid crystals (ILCs) allow the combination of the high ionic conductivity of ionic liquids (ILs) with the supramolecular organization of liquid crystals (LCs). ILCs salts were obtained by the assembly of long-chained diketonylpyridinium cations of the type [HOOR(n)pyH]+ and BF4−, ReO4−, NO3−, CF3SO3−, CuCl42− counter-ions. We have studied the thermal behavior of five series of compounds by differential scanning calorimetry (DSC) and hot stage polarized light optical microscopy (POM). All materials show thermotropic mesomorphism as well as crystalline polymorphism. X-ray diffraction of the [HOOR(12)pyH][ReO4] crystal reveals a layered structure with alternating polar and apolar sublayers. The mesophases also exhibit a lamellar arrangement detected by variable temperature powder X-ray diffraction. The CuCl42− salts exhibit the best LC properties followed by the ReO4− ones due to low melting temperature and wide range of existence. The conductivity was probed for the mesophases in one species each from the ReO4−, and CuCl42− families, and for the solid phase in one of the non-mesomorphic Cl− salts. The highest ionic conductivity was found for the smectic mesophase of the ReO4− containing salt, whereas the solid phases of all salts were dominated by electronic contributions. The ionic conductivity may be favored by the mesophase lamellar structure. PMID:28773485

  3. Contribution of topographically based landslide hazard modelling to the analysis of the spatial distribution and ecology of kauri

    NARCIS (Netherlands)

    Claessens, L.F.G.; Verburg, P.H.; Schoorl, J.M.; Veldkamp, A.

    2006-01-01

    In this paper the use of topographical attributes for the analysis of the spatial distribution and ecological cycle of kauri (Agathis australis), a canopy emergent conifer tree from northern New Zealand, is studied. Several primary and secondary topographical attributes are derived from a Digital

  4. Contribution of topographically based landslide hazard modelling to the analysis of the spatial distribution and ecology of kauri

    NARCIS (Netherlands)

    Claessens, L.F.G.; Verburg, P.H.; Schoorl, J.M.; Veldkamp, A.

    2006-01-01

    In this paper the use of topographical attributes for the analysis of the spatial distribution and ecological cycle of kauri (Agathis australis), a canopy emergent conifer tree from northern New Zealand, is studied. Several primary and secondary topographical attributes are derived from a Digital El

  5. Knowledge Contribution: A New Understanding of Distribution according to“ Knowledge”%知识贡献取向:按“知”分配新探

    Institute of Scientific and Technical Information of China (English)

    庞跃辉

    2001-01-01

    An important change in the contemporary society is that knowledge is being increasingly integrated into economy. Distribution according to the contribution of knowledge has clearly combined the contribution of knowledge with the distribution of value. It is a new way of distribution. Based on divisions of modern knowledge, it is characterized by knowledge possession, distribution, development and application which serve as criterion for value judgement.%当代人类社会的重大变化,显示出知识与经济的同一化、复合化新趋势。按“知”分配使知识贡献与价值分配明确地结合起来;它是建立在现代知识分工基础之上,以知识(智力)资源的占有、配置、开发和使用为最重要因素,并以此衡定其所创造价值大小的一种新型分配方式。

  6. Estimation of Total Fusion Reactivity and Contribution from Suprathermal Tail using 3-parameter Dagum Ion Speed Distribution

    CERN Document Server

    Majumdar, Rudrodip

    2016-01-01

    Thermonuclear fusion reactivity is a pivotal quantity in the studies pertaining to fusion energy production, fusion ignition and energy break-even analysis in both inertially and magnetically confined systems. Although nuclear fusion reactivity and thereafter the power density of a magnetic confinement fusion reactor and the fulfillment of the ignition criterion are quantitatively determined by assuming the ion speed distribution to be Maxwellian, a significant population of suprathermal ions,with energy greater than the quasi-Maxwellian background plasma temperature, is generated by the fusion reactions and auxiliary heating in the fusion devices. In the current work 3-parameter Dagum speed distribution has been introduced to include the effect of suprathermal ion population in the calculation of total fusion reactivity. The extent of enhancement in the fusion reactivity, at different back-ground temperatures of the fusion fuel plasma, due to the suprathermal ion population has also been discussed.

  7. Spatial Distribution of the Cannabinoid Type 1 and Capsaicin Receptors May Contribute to the Complexity of Their Crosstalk

    OpenAIRE

    2016-01-01

    The cannabinoid type 1 (CB1) receptor and the capsaicin receptor (TRPV1) exhibit co-expression and complex, but largely unknown, functional interactions in a sub-population of primary sensory neurons (PSN). We report that PSN co-expressing CB1 receptor and TRPV1 form two distinct sub-populations based on their pharmacological properties, which could be due to the distribution pattern of the two receptors. Pharmacologically, neurons respond either only to capsaicin (COR neurons) or to both cap...

  8. Trace element distributions in surficial sediments of the northern Tyrrhenian Sea: Contribution to heavy-metal pollution assessment

    Science.gov (United States)

    Leoni, Leonardo; Sartori, Franco; Damiani, Vincenzo; Ferretti, Ornella; Viel, Monique

    1991-03-01

    The trace element distributions in surficial sediment of Tyrrhenian Sea have been investigated as a part of a series of studies on the environmental quality of the area off the Tuscany coast (west-central Italy). This research has focused on the presence of possible contaminated zones; it also provides data for the identification and future monitoring and control of pollution sources. The study of numerous surface sediments and core samples has made it possible to distinguish between heavy-metal enrichments related to natural sources and other anomalies caused by anthropogenic contamination. Over much of the basin, the surface Pb, Cu, Zn, and As contents appear considerably enriched relative to those below 15 cm; among these metals, Pb shows the highest and most widespread enrichment. Only in the case of some coarse-grained sediments close to the mouth of Cecina River it is possible to relate anomalously high Zn contents to natural sources. In all other sampling stations, the enrichments of Pb, Cu, Zn, and As are ascribed to man's influence. The sediment distributions of Co, Cr, and Ni do not seem to be related to anthropogenic activities; rather they mirror influx of materials derived from sources of ophiolitic rock. The distribution of barium shows only two significant positive anomalies, and both are related to natural causes. Concentrations of vanadium are high in a zone close to an important smelting plant; these are thought to be of anthropogenic origin.

  9. Trace element distributions in surficial sediments of the northern Tyrrhenian Sea: Contribution to heavy-metal pollution assessment

    Energy Technology Data Exchange (ETDEWEB)

    Leoni, L.; Sartori, F. (Univ. of Pisa, (Italy)); Damiani, V.; Ferretti, O.; Viel, M. (ENEA, La Spezia (Italy))

    The trace element distributions in surficial sediments of Tyrrhenian Sea have been investigated as a part of a series of studies on the environmental quality of the area off the Tuscany coast (west-central Italy). This research has focused on the presence of possible contaminated zones; it also provides data for the identification and future monitoring and control of pollution sources. The study of numerous surface sediments and core samples has made it possible to distinguish between heavy-metal enrichments related to natural sources and other anomalies caused by anthropogenic contamination. Over much of the basin, the surface Pb, Cu, Zn, and As contents appear considerably enriched relative to the those below 15 cm; among these metals. Pb shows the highest and most widespread enrichment. Only in the case of some coarse-grained sediments close to the mouth of Cecina River it is possible to relate anomalously high Zn contents to natural sources. In all other sampling stations, the enrichments of Pb, Cu, Zn, and As are ascribed to man's influence. The sediment distributions of Co, Cr, and Ni do not seem to be related to anthropogenic activities; rather they mirror influx of materials derived from sources of ophiolitic rock. The distribution of barium shows only two significant positive anomalies, and both are related to natural causes. Concentrations of vanadium are high in a zone close to an important smelting plant; these are thought to be of anthropogenic origin.

  10. The role of the counter-ions present in syntheses on the thermal stabilization of strontium and/or calcium apatites

    Energy Technology Data Exchange (ETDEWEB)

    Melo da Silva, Leila; Santos Menezes, Daniela dos; Almeida, Luis Eduardo [Laboratório de Biomateriais – P" 2CEM, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n, São Cristóvão, 49100-000 Sergipe (Brazil); Anselme, Karine; Dentzer, Joseph [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS UMR7361, Université de Haute-Alsace, 15, rue Jean Starcky, BP 2488, 68057 Mulhouse (France); Araujo dos Santos, Euler, E-mail: euler@ufs.br [Laboratório de Biomateriais – P" 2CEM, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n, São Cristóvão, 49100-000 Sergipe (Brazil)

    2015-09-15

    Highlights: • Counter-ions present in syntheses can affect thermal stabilization of apatites. • Ions with different charges and sizes can stabilize the apatite structure. • Co-substitution is an important way to design biomimetic hydroxyapatites. - Abstract: The goal of this work was to study the thermal stabilization of calcium apatites in which the Ca{sup 2+} ions were substituted for Sr{sup 2+} in increasing concentrations via ionic co-substitutions. Two distinct standard syntheses were proposed for comparative purposes: one using counter-ions that were not easily incorporated into the apatite structure (NH{sub 4}{sup +}/NO{sub 3}{sup −}) and one using counter-ions that can be easily incorporated into the structure (Na{sup +}/Cl{sup −}). After calcination, only the apatites synthesized in the presence of NH{sub 4}{sup +}/NO{sub 3}{sup −} presented phase transformation. In contrast, the apatites synthesized in the presence of Na{sup +}/Cl{sup −} formed a solid solution after calcination, with Na{sup +}, Ca{sup 2+}, Sr{sup 2+} and Cl{sup −} sharing the same apatite lattice. Wavelength dispersive X-ray fluorescence spectroscopy (WDXRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and temperature-programmed desorption (TPD) techniques showed that the counter-ions present during the syntheses that are associated with CO{sub 3}{sup 2−} play an important role in the thermal stabilization of the apatites.

  11. WE-AB-204-07: Spatiotemporal Distribution of the FDG PET Tracer in Solid Tumors: Contributions of Diffusion and Convection Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, M [Johns Hopkins University School of Medicine, Baltimore, MD and KNT university, Tehran (Iran, Islamic Republic of); Sefidgar, M [IKI University, Qazvin (Iran, Islamic Republic of); Bazmara, H [KNT university, Tehran (Iran, Islamic Republic of); Sheikhbahaei, S; Marcus, C; Ashrafinia, S; Subramaniam, R; Rahmim, A M [Johns Hopkins University School of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose: In this study, a mathematical model is utilized to simulate FDG distribution in tumor tissue. In contrast to conventional compartmental modeling, tracer distributions across space and time are directly linked together (i.e. moving beyond ordinary differential equations (ODEs) to utilizing partial differential equations (PDEs) coupling space and time). The diffusion and convection transport mechanisms are both incorporated to model tracer distribution. We aimed to investigate the contributions of these two mechanisms on FDG distribution for various tumor geometries obtained from PET/CT images. Methods: FDG transport was simulated via a spatiotemporal distribution model (SDM). The model is based on a 5K compartmental model. We model the fact that tracer concentration in the second compartment (extracellular space) is modulated via convection and diffusion. Data from n=45 patients with pancreatic tumors as imaged using clinical FDG PET/CT imaging were analyzed, and geometrical information from the tumors including size, shape, and aspect ratios were classified. Tumors with varying shapes and sizes were assessed in order to investigate the effects of convection and diffusion mechanisms on FDG transport. Numerical methods simulating interstitial flow and solute transport in tissue were utilized. Results: We have shown the convection mechanism to depend on the shape and size of tumors whereas diffusion mechanism is seen to exhibit low dependency on shape and size. Results show that concentration distribution of FDG is relatively similar for the considered tumors; and that the diffusion mechanism of FDG transport significantly dominates the convection mechanism. The Peclet number which shows the ratio of convection to diffusion rates was shown to be of the order of 10−{sup 3} for all considered tumors. Conclusion: We have demonstrated that even though convection leads to varying tracer distribution profiles depending on tumor shape and size, the domination of

  12. Incorporation of quaternary ammonium salts containing different counterions to improve the performance of inverted perovskite solar cells

    Science.gov (United States)

    Yan, Po-Ruei; Huang, Wei-Jie; Yang, Sheng-Hsiung

    2017-02-01

    In this research, three quaternary ammonium salts containing different counterions, including tetrabutylammonium bromide (TBABr), tetrabutylammonium tetrafluoroborate (TBABF4), and tetrabutylammonium hexafluorophosphate (TBAPF6), were incorporated into [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) as electron transporting layer (ETL). These salts-doped PCBM films revealed higher electron mobility and Fermi levels compared with the un-doped one. Better charge transfer at the interface between perovskite and salts-doped PCBM was also obtained from PL quenching experiments. Inverted perovskite solar cells with the configuration of ITO/PEDOT:PSS/CH3NH3PbI3/PCBM + salts/Ag were fabricated, and the JSC and FF of devices were significantly enhanced using salts-doped PCBM as ETL. The best device based on TBABF4-doped PCBM delivered a power conversion efficiency (PCE) up to 13.41%, which was superior to the one with undoped PCBM layer (PCE = 8.77%).

  13. Size distributions of elemental carbon and its contribution to light extinction in urban and rural locations in the pearl river delta region, China

    Directory of Open Access Journals (Sweden)

    H. Yu

    2010-06-01

    Full Text Available Elemental carbon (EC in size-segregated aerosol samples were determined at five urban, one suburban, and one rural locations in the Pearl River Delta region in South China during 2006–2008 period. The size modal characteristics of EC were different at the urban and suburban/rural locations. The urban EC had a dominant condensation mode with a mass median aerodynamic diameter (MMAD in the 0.36–0.43 μm range and a slightly less abundant mode in the droplet mode size (MMAD: 0.8–1.1 μm, while the suburban/rural EC had a prominent mode in the droplet mode size (MMAD: 0.7–1.1 μm and a minor condensation mode (MMAD: 0.22–0.33 μm. Calculations using Mie theory and the measured size distributions of EC, organic carbon, and major inorganic ions indicate that EC-containing particles contributed 76±20% of the observed light extinction at the urban sites. Among the EC-containing particles, EC mass alone contributed 21±11% of the observed light extinction while non-EC materials on the EC particles (i.e., organic matter, ammonium sulfate, and water contributed 55±15%. At the suburban/rural locations, EC-containing particles contributed 37–48% of the measured light extinction, with EC mass contributing 4–10% and non-EC coating materials contributing the remaining light extinction. Our results suggest that EC-containing particles were important to the overall light extinction in the urban atmospheres due to their more abundant presence from vehicular emissions. The EC-containing particles in the suburban/rural locations had a reduced but still significant contribution to light extinction budget.

  14. Contribution to the study of the geographical distribution of Pyrenean funerary stone circles (baratze, cromlech in the western Pyrenees

    Directory of Open Access Journals (Sweden)

    Jose Miguel EDESO FITO

    2016-07-01

    Full Text Available ‘Baratze’ or Pyrenean funerary stone circles, also known as Pyrenean cromlech, are funerary cremation monuments constructed between the Late Bronze Age and the beginning of the Roman period. These monuments consist of small circles, which consist of isolated standing stone blocks that enclose a central funerary deposit. The densest geographical distribution of Pyrenean funerary stone circles is located east of the Leizaran river and the lower basin of the Oria river up to approximately Andorra. Pyrenean cromlechs are located across mountain chains and occasionally share space with other funerary monuments constructed between the Middle Neolithic period and the Bronze Age –dolmens and cists–, whereas in other locations, cromlechs appear to be established in previously unoccupied mountain zones in an approximately continuous fashion by groups of farmers. The discovery of some Pyrenean circles in Ondarre and Beaskin (Sierra de Aralar, away from the nuclear zone and in a space continuously exploited since the Neolithic period, as indicated by the presence of other funerary monuments –dolmens and cists–, generates new questions regarding their distribution and the reasons for distinct densities of these rituals in some areas of the nuclear zone. Therefore, we propose different explanatory hypotheses, adapted to the distinct circumstances, as lithology, history, etc.

  15. Size distributions of polycyclic aromatic hydrocarbons in the atmosphere and estimation of the contribution of ultrafine particles to their lung deposition.

    Science.gov (United States)

    Kawanaka, Youhei; Tsuchiya, Yoshiteru; Yun, Sun-Ja; Sakamoto, Kazuhiko

    2009-09-01

    This is the first estimation of the contribution of ultrafine particles to the lung deposition of particle-bound polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. The size distributions of nine PAHs (4-6 rings) were measured at roadside and suburban sites in winter in Japan. Deposition efficiencies and fluxes of PAHs in ultrafine mode (2.1 microm) to the human respiratory tract were calculated using the LUDEP computer-based model. From 10%-15% and 4.2%-6.9% of target PAHs were distributed in the ultrafine mode in the roadside and suburban atmosphere, respectively. The model calculations showed that as much as 18%-19% and 16%-17% of inhaled PAHs are deposited in the alveolar region of the lung for the roadside and suburban atmosphere, respectively. Total deposition fluxes of target PAHs in the alveolar region were about 1.5-fold greater for the roadside atmosphere than for the suburban atmosphere. Importantly, ultrafine particles were shown to contribute as much as 23%-30% and 10%-16% to PAH deposition in the alveolar region for the roadside and suburban atmosphere, respectively, although the contributions of ultrafine particles to the total particulate matter masswere only 2.3% in the roadside atmosphere and 1.3% in the suburban atmosphere. These results indicated that ultrafine particles are significant contributors to the deposition of PAHs into the alveolar region of the lung.

  16. Mineralogy, chemistry, and grain size composition of recent sediments in the northern Tyrrhenian Sea: Contribution to the study of sediment transport and distribution

    Science.gov (United States)

    Leoni, Leonardo; Sartori, Franco; Saitta, Maurizio; Damiani, Vincenzo; Ferretti, Ornella; Viel, Monique

    1991-01-01

    As a contribution to an environmental study on Tuscany's marine shelf, textural, mineralogical, and chemical characteristics of recent sediments in the northern Tyrrhenian Sea between Elba Island and Livorno have been analyzed. The data provide clear information on sediment sources and movement patterns. The main sediment source appears to be the Cecina River; very subordinate is the contribution of the Fine River. As to sediment movement patterns, the surveyed basin appears to be divided into two subbasins: (1) a greater, southern subbasin, bounded by Tuscany mainland, Elba Island and Elba Ridge, and Capraia Isle, and Vada Shoals; and (2) a smaller, northern subbasin, enclosed between Vada Shoals and Meloria Shoals (off Livorno port). In the former the coarse-grade Cecina River sediments are transported southward along most of the mainland coast by littoral drift and coastal current; a northward flowing countercurrent seems to be active only in the southernmost part. Silts and clays are distributed in concentric belts around basin's central part, being transported mainly by slow circular water movements. In the marginal western zone, very little terrigenous influx is coupled with a high biologic productivity, and biogenic debris sedimentation prevails there. In the northern subbasin the sediment contribution from Fine River is more appreciable. Here the environmental energies are very low and the coarse sediments are restricted to a few small pocket beaches where they are deposited by local creeks. Most of the subbasin area is occupied by sapropelitic muds, again distributed by slow small-scale gyres.

  17. An exploration of the potential for re-distributed manufacturing to contribute to a sustainable, resilient city

    DEFF Research Database (Denmark)

    Freeman, Rachel; McMahon, Christopher Alan; Godfrey, Patrick

    2017-01-01

    Re-distributed manufacturing (RDM), broadly described as manufacturing done at a smaller-scale and locally, could be beneficial to business and urban society through creating jobs, reducing the environmental impacts of production, and improving resilience to future disturbances. Consideration...... on the city and on manufacturing sectors. The study took an integrated assessment approach which incorporated the development of a conceptual framework; a ‘strawman’ causal loop diagram which was reviewed by participants in a workshop; and a stock and flow system dynamics model that represents our...... understanding about the structure and behaviour of urban manufacturing. Several key themes emerged: similarities between RDM and traditional manufacturing, availability of physical space for RDM to be done, achieving urban resilience through RDM by enabling responsiveness to disturbances, changes...

  18. A review of trends in the distribution of vector-borne diseases: is international trade contributing to their spread?

    Science.gov (United States)

    de La Rocque, S; Balenghien, T; Halos, L; Dietze, K; Claes, F; Ferrari, G; Guberti, V; Slingenbergh, J

    2011-04-01

    It is difficult to determine the part that international trade has played in the expansion of vector-borne diseases, because of the multitude of factors that affect the transformation of habitats and the interfaces between vectors and hosts. The introduction of pathogens through trade in live animals or products of animal origin, as well as the arrival of arthropod vectors, is probably quite frequent but the establishment of an efficient transmission system that develops into a disease outbreak remains the exception. In this paper, based on well-documented examples, the authors review the ecological and epidemiological characteristics of vector-borne diseases that may have been affected in their spread and change of distribution by international trade. In addition, they provide a detailed analysis of the risks associated with specific trade routes and recent expansions of vector populations. Finally, the authors highlight the importance, as well as the challenges, of preventive surveillance and regulation. The need for improved monitoring of vector populations and a readiness to face unpredictable epidemiological events are also emphasised, since this will require rapid reaction, not least in the regulatory context.

  19. Glutamate decarboxylase-dependent acid resistance in Brucella spp.: distribution and contribution to fitness under extremely acidic conditions.

    Science.gov (United States)

    Damiano, Maria Alessandra; Bastianelli, Daniela; Al Dahouk, Sascha; Köhler, Stephan; Cloeckaert, Axel; De Biase, Daniela; Occhialini, Alessandra

    2015-01-01

    Brucella is an expanding genus of major zoonotic pathogens, including at least 10 genetically very close species occupying a wide range of niches from soil to wildlife, livestock, and humans. Recently, we have shown that in the new species Brucella microti, the glutamate decarboxylase (Gad)-dependent system (GAD system) contributes to survival at a pH of 2.5 and also to infection in mice by the oral route. In order to study the functionality of the GAD system in the genus Brucella, 47 isolates, representative of all known species and strains of this genus, and 16 strains of the closest neighbor genus, Ochrobactrum, were studied using microbiological, biochemical, and genetic approaches. In agreement with the genome sequences, the GAD system of classical species was not functional, unlike that of most strains of Brucella ceti, Brucella pinnipedialis, and newly described species (B. microti, Brucella inopinata BO1, B. inopinata-like BO2, and Brucella sp. isolated from bullfrogs). In the presence of glutamate, these species were more acid resistant in vitro than classical terrestrial brucellae. Expression in trans of the gad locus from representative Brucella species in the Escherichia coli MG1655 mutant strain lacking the GAD system restored the acid-resistant phenotype. The highly conserved GAD system of the newly described or atypical Brucella species may play an important role in their adaptation to acidic external and host environments. Furthermore, the GAD phenotype was shown to be a useful diagnostic tool to distinguish these latter Brucella strains from Ochrobactrum and from classical terrestrial pathogenic Brucella species, which are GAD negative.

  20. The role of the contribution of the whole sea energy on pollution distribution and biocenosis quality: a case study in the Northern Tyrrhenian Sea, Italy

    Science.gov (United States)

    Bonamano, Simone; Piermattei, Viviana; Piazzolla, Daniele; Paladini de Mendoza, Francesco; Manfredi Frattarelli, Francesco; Mancini, Emanuele; Cognetti de Martiis, Selvaggia; Madonia, Alice; Martellucci, Riccardo; Stefanì, Chiara; Pierattini, Alberto; Scanu, Sergio; Marcelli, Marco

    2016-04-01

    Marine sediments and benthic biocenosis record, at different spatial and temporal scales, natural and anthropogenic processes that occur in the water column. The coastal area of Civitavecchia, in the Tyrrhenian Sea, Italy, presents valuable marine and coastal ecosystems, which are subject to pollution due to the presence of potentially impactful uses of the coastline (the most important port for traffic passenger in the Mediterranean sea and one of the biggest energy production site in Europe) that overlap with the presence of natural geogenic anomalies related to the concentrations of some trace elements. The C-CEMS monitoring system, currently available in the study area, is able to perform the analysis of pollutants dispersion in coastal waters using in situ and remote observations coupled with numerical models simulations . In particular, water column parameters trends and the distribution of both benthic biocenosis and pollutants from natural sources and human activities in the water column can be assessed. This work focuses on the distribution patterns of pollutants and its relationship with the distribution of the benthic community in relation to biocenosis. Moreover, this work presents a first attempt to relate the whole sea energy contribution, which has effects on both the deposition of fine material and pollutants associated with it, and the distribution of communities, in terms of "exosomatic energy" (sensu Margalef).

  1. Simulation of particle size distribution with a global aerosol model: contribution of nucleation to aerosol and CCN number concentrations

    Directory of Open Access Journals (Sweden)

    F. Yu

    2009-04-01

    Full Text Available An advanced particle microphysics model with a number of computationally efficient schemes has been incorporated into a global chemistry transport model (GEOS-Chem to simulate particle number size distributions and cloud condensation nuclei (CCN concentrations in the atmosphere. Size-resolved microphysics for secondary particles (i.e., those formed from gaseous species and sea salt has been treated in the present study. The growth of nucleated particles through the condensation of sulfuric acid vapor and equilibrium uptake of nitrate, ammonium, and secondary organic aerosol is explicitly simulated, along with the scavenging of secondary particles by primary particles (dust, black carbon, organic carbon, and sea salt. We calculate secondary particle formation rate based on ion-mediated nucleation (IMN mechanism and constrain the parameterizations of primary particle emissions with various observations. Our simulations indicate that secondary particles formed via IMN appear to be able to account for the particle number concentrations observed in many parts of troposphere. A comparison of the simulated annual mean concentrations of condensation nuclei larger than 10 nm (CN10 with those measured values show very good agreement (within a factor of two in near all 22 sites around the globe that have at least one full year of CN10 measurements. Secondary particles appear to dominate the number abundance in most parts of the troposphere. Calculated CCN concentration at supersaturation of 0.4% (CCN0.4 and the fraction of CCN0.4 that is secondary (fCCNsec have large spatial variations. Over the middle latitude in the Northern Hemisphere, zonally averaged CCN0.4 decreases from ~400–700 cm−3 in the boundary layer (BL to below 100 cm−3 above altitude of ~4 km, the corresponding fCCNsec values change from 50–60% to above ~70%. In the Southern Hemisphere, the zonally

  2. Simulation of particle size distribution with a global aerosol model: contribution of nucleation to aerosol and CCN number concentrations

    Directory of Open Access Journals (Sweden)

    F. Yu

    2009-10-01

    Full Text Available An advanced particle microphysics model with a number of computationally efficient schemes has been incorporated into a global chemistry transport model (GEOS-Chem to simulate particle number size distributions and cloud condensation nuclei (CCN concentrations in the atmosphere. Size-resolved microphysics for secondary particles (i.e., those formed from gaseous species and sea salt has been treated in the present study. The growth of nucleated particles through the condensation of sulfuric acid vapor and equilibrium uptake of nitrate, ammonium, and secondary organic aerosol is explicitly simulated, along with the scavenging of secondary particles by primary particles (dust, black carbon, organic carbon, and sea salt. We calculate secondary particle formation rate based on ion-mediated nucleation (IMN mechanism and constrain the parameterizations of primary particle emissions with various observations. Our simulations indicate that secondary particles formed via IMN appear to be able to account for the particle number concentrations observed in many parts of the troposphere. A comparison of the simulated annual mean concentrations of condensation nuclei larger than 10 nm (CN10 with those measured values show very good agreement (within a factor of two in near all 22 sites around the globe that have at least one full year of CN10 measurements. Secondary particles appear to dominate the number abundance in most parts of the troposphere. Calculated CCN concentration at supersaturation of 0.4% (CCN0.4 and the fraction of CCN0.4 that is secondary (fsecCCN have large spatial variations. Over the middle latitude in the Northern Hemisphere, zonally averaged CCN0.4 decreases from ~400–700 cm−3 in the boundary layer (BL to below 100 cm−3 above altitude of ~4 km, the corresponding fsecCCN values change from 50–60% to above ~70%. In the Southern Hemisphere, the zonally

  3. ²H enrichment distribution of hepatic glycogen from ²H₂O reveals the contribution of dietary fructose to glycogen synthesis.

    Science.gov (United States)

    Delgado, Teresa C; Martins, Fátima O; Carvalho, Filipa; Gonçalves, Ana; Scott, Donald K; O'Doherty, Robert; Macedo, M Paula; Jones, John G

    2013-02-15

    Dietary fructose can benefit or hinder glycemic control, depending on the quantity consumed, and these contrasting effects are reflected by alterations in postprandial hepatic glycogen synthesis. Recently, we showed that ²H enrichment of glycogen positions 5 and 2 from deuterated water (²H₂O) informs direct and indirect pathway contributions to glycogenesis in naturally feeding rats. Inclusion of position 6(S) ²H enrichment data allows indirect pathway sources to be further resolved into triose phosphate and Krebs cycle precursors. This analysis was applied to six rats that had fed on standard chow (SC) and six rats that had fed on SC plus 35% sucrose in their drinking water (HS). After 2 wk, hepatic glycogenesis sources during overnight feeding were determined by ²H₂O administration and postmortem analysis of glycogen ²H enrichment at the conclusion of the dark period. Net overnight hepatic glycogenesis was similar between SC and HS rodents. Whereas direct pathway contributions were similar (403 ± 71 μmol/g dry wt HS vs. 578 ± 76 μmol/g dry wt SC), triose phosphate contributions were significantly higher for HS compared with SC (382 ± 61 vs. 87 ± 24 μmol/g dry wt, P vs. 197 ± 32 μmol/g dry wt, P glucose ²H enrichments at the end of the feeding period also revealed a significantly higher fractional contribution of triose phosphate to plasma glucose levels in HS vs. SC. Hence, the ²H enrichment distributions of hepatic glycogen and glucose from ²H₂O inform the contribution of dietary fructose to hepatic glycogen and glucose synthesis.

  4. Mineralogy, chemistry, and grain size composition of recent sediments in the northern Tyrrhenian Sea: Contribution to the study of sediment transport and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Leoni, L.; Sartori, F.; Saitta, M. (Univ. of Pisa (Italy)); Damiani, V.; Ferretti, O.; Viel, M. (ENEA, La Spezia (Italy))

    As a contribution to an environmental study on Tuscany's marine shelf, textural, mineralogical, and chemical characteristics of recent sediments in the northern Tyrrhenian Sea between Elba Island and Livorno have been analyzed. The data provide clear information on sediment sources and movement patterns. The main sediment sources and movement patterns. The main sediment source appears to be the Cecina River; very subordinate is the contribution of the Fine River. As to sediment movement patterns, the surveyed basin appears to be divided into two subbasins: (1) a greater, southern subbasin, bounded by Tuscany mainland, Elba Island and Ridge, and Capraia Isle, and Vada Shoals; and (2) a smaller, northern subbasin, enclosed between Vada Shoals and Meloria Shoals (off Livorno port). In the former the coarse-grade Cecina River sediments are transported southward along most of the mainland coast by littoral drift and coastal current; a northward flowing counter-current seems to be active only in the southernmost part. Silts and clays are distributed in concentric belts around basin's central part, being transported mainly by slow circular water movements. In the marginal western zone, very little terrigenous influx is coupled with a high biologic productivity, and biogenic debris sedimentation prevails there. In the northern subbasin the sediment contribution from Fine River is more appreciable. Here the environmental energies are very low and the coarse sediments are restricted to a few small pocket beaches where they are deposited by local creeks. Most of the subbasin area is occupied by sapropelitic muds, again distributed by slow small-scale gyres.

  5. Aspartate-histidine interaction in the retinal schiff base counterion of the light-driven proton pump of Exiguobacterium sibiricum.

    Science.gov (United States)

    Balashov, S P; Petrovskaya, L E; Lukashev, E P; Imasheva, E S; Dioumaev, A K; Wang, J M; Sychev, S V; Dolgikh, D A; Rubin, A B; Kirpichnikov, M P; Lanyi, J K

    2012-07-24

    One of the distinctive features of eubacterial retinal-based proton pumps, proteorhodopsins, xanthorhodopsin, and others, is hydrogen bonding of the key aspartate residue, the counterion to the retinal Schiff base, to a histidine. We describe properties of the recently found eubacterium proton pump from Exiguobacterium sibiricum (named ESR) expressed in Escherichia coli, especially features that depend on Asp-His interaction, the protonation state of the key aspartate, Asp85, and its ability to accept a proton from the Schiff base during the photocycle. Proton pumping by liposomes and E. coli cells containing ESR occurs in a broad pH range above pH 4.5. Large light-induced pH changes indicate that ESR is a potent proton pump. Replacement of His57 with methionine or asparagine strongly affects the pH-dependent properties of ESR. In the H57M mutant, a dramatic decrease in the quantum yield of chromophore fluorescence emission and a 45 nm blue shift of the absorption maximum with an increase in the pH from 5 to 8 indicate deprotonation of the counterion with a pK(a) of 6.3, which is also the pK(a) at which the M intermediate is observed in the photocycle of the protein solubilized in detergent [dodecyl maltoside (DDM)]. This is in contrast with the case for the wild-type protein, for which the same experiments show that the major fraction of Asp85 is deprotonated at pH >3 and that it protonates only at low pH, with a pK(a) of 2.3. The M intermediate in the wild-type photocycle accumulates only at high pH, with an apparent pK(a) of 9, via deprotonation of a residue interacting with Asp85, presumably His57. In liposomes reconstituted with ESR, the pK(a) values for M formation and spectral shifts are 2-3 pH units lower than in DDM. The distinctively different pH dependencies of the protonation of Asp85 and the accumulation of the M intermediate in the wild-type protein versus the H57M mutant indicate that there is strong Asp-His interaction, which substantially lowers

  6. Aspartate-Histidine Interaction in the Retinal Schiff Base Counterion of the Light-Driven Proton Pump of Exiguobacterium sibiricum†

    Science.gov (United States)

    Balashov, S.P.; Petrovskaya, L.E.; Lukashev, E.P.; Imasheva, E.S.; Dioumaev, A.K.; Wang, J.M.; Sychev, S.V.; Dolgikh, D.A.; Rubin, A.B.; Kirpichnikov, M.P.; Lanyi, J.K.

    2012-01-01

    One of the distinctive features of eubacterial retinal based proton pumps, proteorhodopsins, xanthorhodopsin and others, is hydrogen bonding of the key aspartate residue, the counterion to the retinal Schiff base, to a histidine. We describe properties of the recently found eubacterium proton pump from Exiguobacterium sibiricum (named ESR) expressed in E. coli, especially features that depend on Asp-His interaction, the protonation state of the key aspartate, Asp85, and its ability to accept proton from the Schiff base during the photocycle. Proton pumping by liposomes and E. coli cells containing ESR occurs in a broad pH range above pH 4.5. Large light-induced pH changes indicate that ESR is a potent proton pump. Replacement of His57 with methionine or asparagine strongly affects the pH dependent properties of ESR. In the H57M mutant a dramatic decrease in the quantum yield of chromophore fluorescence emission and a 45 nm blue shift of the absorption maximum upon raising the pH from 5 to 8 indicates deprotonation of the counterion with a pKa of 6.3, which is also the pKa at which the M intermediate is observed in the photocycle of the protein solubilized in detergent (DDM). This is in contrast with the wild type protein, in which the same experiments show that the major fraction of Asp85 is deprotonated at pH > 3 and that it protonates only at low pH, with a pKa of 2.3. The M intermediate in the wild type photocycle accumulates only at high pH, with an apparent pKa of 9 from deprotonation of a residue interacting with Asp85, presumably His57. In liposomes reconstituted with ESR the pKas for M formation and spectral shifts are 2–3 pH units lower than in DDM. The distinctively different pH dependencies of the protonation of Asp85 and the accumulation of the M intermediate in the wild type protein vs. the H57M mutant indicate that there is strong Asp-His interaction, which substantially lowers the pKa of Asp85 by stabilizing its deprotonated state. PMID:22738070

  7. Excluded volume effect of counterions and water dipoles near a highly charged surface due to a rotationally averaged Boltzmann factor for water dipoles.

    Science.gov (United States)

    Gongadze, Ekaterina; Iglič, Aleš

    2013-03-01

    Water ordering near a negatively charged electrode is one of the decisive factors determining the interactions of an electrode with the surrounding electrolyte solution or tissue. In this work, the generalized Langevin-Bikerman model (Gongadze-Iglič model) taking into account the cavity field and the excluded volume principle is used to calculate the space dependency of ions and water number densities in the vicinity of a highly charged surface. It is shown that for high enough surface charged densities the usual trend of increasing counterion number density towards the charged surface may be completely reversed, i.e. the drop in the counterions number density near the charged surface is predicted.

  8. The roles of counterion and water in a stereoselective cysteine-catalyzed Rauhut-Currier reaction: a challenge for computational chemistry.

    Science.gov (United States)

    Osuna, Sílvia; Dermenci, Alpay; Miller, Scott J; Houk, K N

    2013-10-11

    The stereoselective Rauhut-Currier (RC) reaction catalyzed by a cysteine derivative has been explored computationally with density functional theory (M06-2X). Both methanethiol and a chiral cysteine derivative were studied as nucleophiles. The complete reaction pathway involves rate-determining elimination of the thiol catalyst from the Michael addition product. The stereoselective Rauhut-Currier reaction, catalyzed by a cysteine derivative as a nucleophile, has also been studied in detail. This reaction was experimentally found to be extremely sensitive to the reaction conditions, such as the number of water equivalents and the effect of potassium counterion. The E1cB process for catalyst elimination has been explored computationally for the eight possible stereoisomers. The effect of explicit water solvation and the presence of counterion (either K(+) or Na(+) ) has been studied for the lowest energy enantiomer pair (1S, 2R, 3S)/(1R, 2S, 3R).

  9. Counterions control whether self-assembly leads to formation of stable and well-defined unilamellar nanotubes or nanoribbons and nanorods

    DEFF Research Database (Denmark)

    Shi, Dong; Schwall, Christian; Sfintes, George

    2014-01-01

    Self-assembly of the amphiphilic π-conjugated carbenium ion ATOTA-1(+) in aqueous solution selectively leads to discrete and highly stable nanotubes or nanoribbons and nanorods, depending on the nature of the counterion (Cl(-) vs. PF6(-), respectively). The nanotubes formed by the Cl(-) salt...... illustrate an exceptional example of a structural well-defined (29±2 nm in outer diameter) unilamellar tubular morphology featuring π-conjugated functionality and high stability and flexibility, in aqueous solution....

  10. Understanding Hydrogen Sorption in In- soc -MOF: A Charged Metal-Organic Framework with Open-Metal Sites, Narrow Channels, and Counterions

    KAUST Repository

    Pham, Tony

    2015-03-04

    © 2015 American Chemical Society. Grand canonical Monte Carlo (GCMC) simulations of hydrogen sorption were performed in In-soc-MOF, a charged metal-organic framework (MOF) that contains In3O trimers coordinated to 5,5′-azobis(1,3-benzenedicarboxylate) linkers. The MOF contains nitrate counterions that are located in carcerand-like capsules of the framework. This MOF was shown to have a high hydrogen uptake at 77 K and 1.0 atm. The simulations were performed with a potential that includes explicit many-body polarization interactions, which were important for modeling gas sorption in a charged/polar MOF such as In-soc-MOF. The simulated hydrogen sorption isotherms were in good agreement with experiment in this challenging platform for modeling. The simulations predict a high initial isosteric heat of adsorption, Qst, value of about 8.5 kJ mol-1, which is in contrast to the experimental value of 6.5 kJ mol-1 for all loadings. The difference in the Qst behavior between experiment and simulation is attributed to the fact that, in experimental measurements, the sorbate molecules cannot access the isolated cages containing the nitrate ions, the most energetically favorable site in the MOF, at low pressures due to an observed diffusion barrier. In contrast, the simulations were able to capture the sorption of hydrogen onto the nitrate ions at low loading due to the equilibrium nature of GCMC simulations. The experimental Qst values were reproduced in simulation by blocking access to all of the nitrate ions in the MOF. Furthermore, at 77 K, the sorbed hydrogen molecules were reminiscent of a dense fluid in In-soc-MOF starting at approximately 5.0 atm, and this was verified by monitoring the isothermal compressibility, βT, values. The favorable sites for hydrogen sorption were identified from the polarization distribution as the nitrate ions, the In3O trimers, and the azobenzene

  11. Interaction of counterions with subtilisin in acetonitrile: insights from molecular dynamics simulations.

    Science.gov (United States)

    Lousa, Diana; Cianci, Michele; Helliwell, John R; Halling, Peter J; Baptista, António M; Soares, Cláudio M

    2012-05-24

    A recent X-ray structure has enabled the location of chloride and cesium ions on the surface of subtilisin Carlsberg in acetonitrile soaked crystals. (1) To complement the previous study and analyze the system in solution, molecular dynamics (MD) simulations, in acetonitrile, were performed using this structure. Additionally, Cl(-) and Cs(+) ions were docked on the protein surface and this system was also simulated. Our results indicate that chloride ions tend to stay close to the protein, whereas cesium ions frequently migrate to the solvent. The distribution of the ions around the enzyme surface is not strongly biased by their initial locations. Replacing cesium by sodium ions showed that the distribution of the two cations is similar, indicating that Cs(+) can be used to find the binding sites of cations like Na(+) and K(+), which, unlike Cs(+), have physiological and biotechnological roles. The Na(+)Cl(-) is more stable than the Cs(+)Cl(-) ion pair, decreasing the probability of interaction between Cl(-) and subtilisin. The comparison of water and acetonitrile simulations indicates that the solvent influences the distribution of the ions. This work provides an extensive theoretical analysis of the interaction between ions and the model enzyme subtilisin in a nonaqueous medium.

  12. Highly conserved glutamic acid in the extracellular IV–V loop in rhodopsins acts as the counterion in retinochrome, a member of the rhodopsin family

    Science.gov (United States)

    Terakita, Akihisa; Yamashita, Takahiro; Shichida, Yoshinori

    2000-01-01

    Retinochrome is a member of the rhodopsin family having a chromophore retinal and functioning as a retinal photoisomerase in squid photoreceptor cells. Unlike vertebrate rhodopsins, but like many invertebrate rhodopsins, retinochrome does not have a glutamic acid at position 113 to serve as a counterion for the protonated retinylidene Schiff base. Here we investigated possible counterions in retinochrome by site-specific mutagenesis. Our results showed that the counterion is the glutamic acid at position 181, at which almost all the pigments in the rhodopsin family, including vertebrate and invertebrate rhodopsins, have a glutamic or aspartic acid. The remarkable exceptions are the long-wavelength visual pigments that have a histidine that, together with a nearby lysine, serves as a chloride-binding site. Replacement of Glu-181 of bovine rhodopsin with Gln caused a 10-nm red-shift of absorption maximum. Because the position at 181 is in the extracellular loop connecting the transmembrane helices VI and V, these results demonstrate the importance of this loop to function for spectral tuning in the rhodopsin family. PMID:11106382

  13. Controlling the thermodynamic stability of intermediate phases in a cationic-amphiphile-water system with strongly binding counterions.

    Science.gov (United States)

    Gupta, Santosh Prasad; Raghunathan, V A

    2013-07-01

    We have studied the influence of two structurally isomeric organic salts, namely, 2-sodium-3-hydroxy naphthoate (SHN) and 1-sodium-2-hydroxy naphthoate (SHN1), on the phase behavior of concentrated aqueous solutions of the cationic surfactant cetylpyridinium chloride (CPC). Partial phase diagrams of the two systems have been constructed using polarizing optical microscopy and x-ray diffraction techniques. A variety of intermediate phases is seen in both systems for a range of salt concentrations. The CPC-SHN-water system exhibits the rhombohedral and tetragonal mesh phases in addition to the random mesh phase, whereas the CPC-SHN1-water system shows only the tetragonal and random mesh phases. The CPC-SHN-water system also exhibits two nematic phases consisting of cylindrical and disk-like micelles at relatively low and high salt concentrations, respectively. These results show that the concentration of the strongly bound counterion provided by the organic salt can be used as a control parameter to tune the stability of different intermediate phases in amphiphile-water systems.

  14. Facile colorimetric method for simple and rapid detection of endotoxin based on counterion-mediated gold nanorods aggregation.

    Science.gov (United States)

    Wang, Yashan; Zhang, Daohong; Liu, Wei; Zhang, Xiao; Yu, Shaoxuan; Liu, Tao; Zhang, Wentao; Zhu, Wenxin; Wang, Jianlong

    2014-05-15

    Existence of endotoxin in food and injection products indicates bacterial contaminations and therefore poses threat to human health. Herein, a simple and rapid colorimetric method for the effective detection of endotoxin in food and injections based on counterion-mediated gold nanorods aggregation is first proposed. By taking advantage of the color change of unmodified gold nanorods resulted from endotoxin mediated gold nanorods aggregation, endotoxin could be detected in the concentration range of 0.01-0.6 μM. Further, we studied the performance of gold nanorods with different aspect ratios (2.7 and 3.3) in determination of endotoxin and found that gold nanorods with higher aspect ratio (AR) showed superiority in the sensing sensitivity of endotoxin. A good specificity for endotoxin, a detection limit of 0.0084 μM and recoveries ranging from 84% to 109% in spiked food and injection samples are obtained with the colorimetric method. Results demonstrate that the present method provides a novel and effective approach for on-site screening of endotoxin in common products, which is beneficial for monitoring and reducing the risk of bacterial contaminations in food and injections production.

  15. Direct measurement of the intermolecular forces between counterion-condensed DNA double helices. Evidence for long range attractive hydration forces.

    Science.gov (United States)

    Rau, D C; Parsegian, V A

    1992-01-01

    Rather than acting by modifying van der Waals or electrostatic double layer interactions or by directly bridging neighboring molecules, polyvalent ligands bound to DNA double helices appear to act by reconfiguring the water between macromolecular surfaces to create attractive long range hydration forces. We have reached this conclusion by directly measuring the repulsive forces between parallel B-form DNA double helices pushed together from the separations at which they have self organized into hexagonal arrays of parallel rods. For all of the wide variety of "condensing agents" from divalent Mn to polymeric protamines, the resulting intermolecular force varies exponentially with a decay rate of 1.4-1.5 A, exactly one-half that seen previously for hydration repulsion. Such behavior qualitatively contradicts the predictions of all electrostatic double layer and van der Waals force potentials previously suggested. It fits remarkably well with the idea, developed and tested here, that multivalent counterion adsorption reorganizes the water at discrete sites complementary to unadsorbed sites on the apposing surface. The measured strength and range of these attractive forces together with their apparent specificity suggest the presence of a previously unexpected force in molecular organization.

  16. Parton distributions incorporating QED contributions

    CERN Document Server

    Martin, A D; Stirling, W J; Thorne, R S

    2004-01-01

    We perform a global parton analysis of deep inelastic and related hard-scattering data, including ${\\cal O}(\\alpha_{\\rm QED})$ corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two important physical consequences. First, the different DGLAP evolution of u and d type quarks introduces isospin violation, i.e. $u^p \

  17. Common Distribution of gad Operon in Lactobacillus brevis and its GadA Contributes to Efficient GABA Synthesis toward Cytosolic Near-Neutral pH

    Science.gov (United States)

    Wu, Qinglong; Tun, Hein Min; Law, Yee-Song; Khafipour, Ehsan; Shah, Nagendra P.

    2017-01-01

    Many strains of lactic acid bacteria (LAB) and bifidobacteria have exhibited strain-specific capacity to produce γ-aminobutyric acid (GABA) via their glutamic acid decarboxylase (GAD) system, which is one of amino acid-dependent acid resistance (AR) systems in bacteria. However, the linkage between bacterial AR and GABA production capacity has not been well established. Meanwhile, limited evidence has been provided to the global diversity of GABA-producing LAB and bifidobacteria, and their mechanisms of efficient GABA synthesis. In this study, genomic survey identified common distribution of gad operon-encoded GAD system in Lactobacillus brevis for its GABA production among varying species of LAB and bifidobacteria. Importantly, among four commonly distributed amino acid-dependent AR systems in Lb. brevis, its GAD system was a major contributor to maintain cytosolic pH homeostasis by consuming protons via GABA synthesis. This highlights that Lb. brevis applies GAD system as the main strategy against extracellular and intracellular acidification demonstrating its high capacity of GABA production. In addition, the abundant GadA retained its activity toward near-neutral pH (pH 5.5–6.5) of cytosolic acidity thus contributing to efficient GABA synthesis in Lb. brevis. This is the first global report illustrating species-specific characteristic and mechanism of efficient GABA synthesis in Lb. brevis. PMID:28261168

  18. Contribution à la ré-évaluation de l’aire de répartition du singe à queue de soleil (Cercopithecus solatus Contribution to the reassessment of the the sun-tailed monkey (Cercopithecus solatus distribution area

    Directory of Open Access Journals (Sweden)

    Peggy Motsch

    2011-05-01

    encourage conservation. For nearly two years, new data were acquired, in particular on the distribution area of the species. Here is the study of the southeastern limit. Thus, our study was conducted in three regions of Gabon, where the presence of C. solatus was either demonstrated (historic area, or suspected, or had never been studied before. Surveys in villages and recce walking in the field have been carried out. The results 1 / confirmed the presence of C. solatus in the historic area, 2 / seem to support the assumptions of its presence beyond the historic area, and 3 / even suggest that C. solatus would be further south-east and closer to the Republic of Congo that what was previously thought. This study contributed to reassess the distribution of populations of C. solatus within the Gabonese territory, and therefore provided additional tools to assess the conservation status of the species.

  19. Abundance and distribution of major groups of diazotrophic cyanobacteria and their potential contribution to N₂ fixation in the tropical Atlantic Ocean.

    Science.gov (United States)

    Goebel, Nicole L; Turk, Kendra A; Achilles, Katherine M; Paerl, Ryan; Hewson, Ian; Morrison, Amanda E; Montoya, Joseph P; Edwards, Christopher A; Zehr, Jonathan P

    2010-12-01

    The abundances of six N₂-fixing cyanobacterial phylotypes were profiled at 22 stations across the tropical Atlantic Ocean during June 2006, and used to model the contribution of the diazotrophs to N₂ fixation. Diazotroph abundances were measured by targeting the nifH gene of Trichodesmium, unicellular groups A, B, C (UCYN-A, UCYN-B and UCYN-C), and diatom-cyanobiont symbioses Hemiaulus-Richelia, Rhizosolenia-Richelia and Chaetoceros-Calothrix. West to east gradients in temperature, salinity and nutrients [NO₃⁻ + NO₂⁻, PO₄³⁻, Si(OH)₄] showed the influence of the Amazon River plume and its effect on the distributions of the diazotrophs. Trichodesmium accounted for more than 93% of all nifH genes detected, dominated the warmer waters of the western Atlantic, and was the only diazotroph detected at the equatorial upwelling station. UCYN-A was the next most abundant (> 5% of all nifH genes) and dominated the cooler waters of the eastern Atlantic near the Cape Verde Islands. UCYN-C was found at a single depth (200 m) of high salinity and low temperature and nutrients, whereas UCYN-B cells were widespread but in very low abundance (6.1 × 10¹ ± 4.6 × 10² gene copies l⁻¹). The diatom-cyanobionts were observed primarily in the western Atlantic within or near the high Si(OH)₄ input of the Amazon River plume. Overall, highest diazotroph abundances were observed at the surface and declined with depth, except for some subsurface peaks in Trichodesmium, UCYN-B and UCYN-A. Modelled contributions of Trichodesmium, UCYN-B and UCYN-A to total N₂ fixation suggested that Trichodesmium had the largest input, except for the potential of UCYN-A at the Cape Verde Islands.

  20. Polymer micelles with hydrophobic core and ionic amphiphilic corona. 1. Statistical distribution of charged and nonpolar units in corona.

    Science.gov (United States)

    Lysenko, Evgeny A; Kulebyakina, Alevtina I; Chelushkin, Pavel S; Rumyantsev, Artem M; Kramarenko, Elena Yu; Zezin, Alexander B

    2012-12-11

    Polymer micelles with hydrophobic polystyrene (PS) core and ionic amphiphilic corona from charged N-ethyl-4-vinylpyridinium bromide (EVP) and uncharged 4-vinylpyridine (4VP) units spontaneously self-assembled from PS-block-poly(4VP-stat-EVP) macromolecules in mixed dimethylformamide/methanol/water solvent. The fraction of statistically distributed EVP units in corona-forming block is β = [EVP]/([EVP]+[4VP]) = 0.3-1. Micelles were transferred into water via dialysis technique, and pH was adjusted to 9, where 4VP is insoluble. Structural characteristics of micelles were investigated both experimentally and theoretically as a function of corona composition β. Methods of dynamic and static light scattering, electrophoretic mobility measurements, sedimentation velocity, transmission electron microscopy, and UV spectrophotometry were applied. All micelles possessed spherical morphology. The aggregation number, structure, and electrophoretic mobility of micelles changed in a jumplike manner near β ~ 0.6-0.75. Below and above this region, micelle characteristics were constant or insignificantly changed upon β. Theoretical dependencies for micelle aggregation number, corona dimensions, and fraction of small counterions outside corona versus β were derived via minimization the micelle free energy, taking into account surface, volume, electrostatic, and elastic contributions of chain units and translational entropy of mobile counterions. Theoretical estimations also point onto a sharp structural transition at a certain corona composition. The abrupt reorganization of micelle structure at β ~ 0.6-0.75 entails dramatic changes in micelle dispersion stability in the presence of NaCl or in the presence of oppositely charged polymeric (sodium polymethacrylate) or amphiphilic (sodium dodecyl sulfate) complexing agents.

  1. The Influence of the Anionic Counter-Ion on the Activity of Ammonium Substituted Hoveyda-Type Olefin Metathesis Catalysts in Aqueous Media

    Science.gov (United States)

    Gułajski, Łukasz; Grela, Karol

    Polar olefin metathesis catalysts, bearing an ammonium group are presented. The electron withdrawing ammonium group not only activates the catalysts electronically, but at the same time makes the catalysts more hydrophilic. Catalysts can be therefore efficiently used not only in traditional media, such as methylene chloride and toluene, but also in technical-grade alcohols, alcohol— water mixtures and in neat water. Finally, in this overview the influence of the anionic counter-ion on the activity of ammonium substituted Hoveyda-type olefin metathesis catalysts in aqueous media is presented.

  2. Characteristics and distribution patterns of snow and meteoric ice in the Weddell Sea and their contribution to the mass balance of sea ice

    Directory of Open Access Journals (Sweden)

    Hajo Eicken

    Full Text Available Based on snow- and ice-thickness measurements at >11 000 points augmented by snow- and icecore studies during 4 expeditions from 1986 - 92 in the Weddell Sea, we describe characteristics and distribution patterns of snow and meteoric ice and assess their importance for the mass balance of sea ice. For first-year ice (FY in the central and eastern Weddell Sea, mean snow depth amounts to 0.16 m (mean ice thickness 0.75 m compared to 0.53 m (mean ice thickness 1.70 m for second-year ice (SY in the northwestern Weddell Sea. Ridged ice retains a thicker snow cover than level ice, with ice thickness and snow depth negatively correlated for the latter, most likely due to aeolian redistribution. During the different expeditions, 8, 15, 17 and 40% of all drill holes exhibited negative freeboard. As a result of flooding and brine seepage into the snow pack, snow salinities averaged 4‰. Through 18O measurements the distribution of meteoric ice (i.e. precipitation in the sea-ice cover was assessed. Roughly 4% of the total ice thickness consist of meteoric ice (FY 3%, SY 5%. With a mean density of 290 kg/m3, the snow cover itself contributes 8% to total ice mass (7% FY, 11% SY. Analysis of 18O in snow indicates a local maximum in accumulation in the 65 to 75°S latitude zone. Hydrogen peroxide in the snow has proven useful as a temporal tracer and for identification of second-year floes. Drawing on accumulation data from stations at the Weddell Sea coast, it becomes clear that the onset of ice growth is important for the evolution of ice thickness and the interaction between ice and snow. Loss of snow to leads due to wind drift may be considerable, yet is reduced owing to metamorphic processes in the snow column. This is confirmed by a comparison of accumulation data from coastal stations and from snow depths over sea ice. Temporal and spatial accumulation patterns of snow are shown to be important in controlling

  3. Submicron aerosols at thirteen diversified sites in China: size distribution, new particle formation and corresponding contribution to cloud condensation nuclei production

    Directory of Open Access Journals (Sweden)

    J. F. Peng

    2014-06-01

    Full Text Available Understanding the particle number size distributions in diversified atmospheric environments is important in order to design mitigation strategies related to submicron particles and their effect on regional air quality, haze and human health. In this study, we conducted 15 different field measurement campaigns, each one-month long, between 2007 and 2011 at 13 individual sites in China. These were 5 urban sites, 4 regional sites, 3 coastal/background sites and one ship cruise measurement along eastern coastline of China. Size resolved particles were measured in the 15–600 nm size range. The median particle number concentrations (PNC were found to vary in the range of 1.1–2.2 × 104 cm−3 at urban sites, 0.8–1.5 × 104 cm−3 at regional sites, 0.4–0.6 × 104 cm−3 at coastal/background sites, and 0.5 × 104 cm−3 during cruise measurements. Peak diameters at each of these sites varied greatly from 24 nm to 115 nm. Particles in the 15–25 nm (nucleation mode, 25–100 nm (Aitken mode and 100–600 nm (accumulation mode range showed different characteristics at each of the studied sites, indicating the features of primary emissions and secondary formation in these diversified atmospheric environments. Diurnal variations show a build-up of accumulation mode particles belt at regional sites, suggesting the contribution of regional secondary aerosol pollution. Frequencies of new particle formation (NPF events were much higher at urban and regional sites than at coastal sites and cruise measurement. The average growth rates (GRs of nucleation mode particles were 8.0–10.9 nm h−1 at urban sites, 7.4–13.6 nm h−1 at regional sites and 2.8–7.5 nm h−1 at both coastal and cruise measurement sites. The high gaseous precursors and strong oxidation at urban and regional sites not only favored the formation of particles, but also accelerated the growth rate of the nucleation mode particles. No significant difference in condensation sink

  4. A Profile of Corporate Contributions.

    Science.gov (United States)

    Smith, Hayden W.

    The extent and distribution of charitable contributions by corporations were studied. In addition to a history of giving from 1936 to 1981, information is presented on corporate contributions in 1977 in terms of the distribution of companies (1) by size of contributions, (2) by contributions as percentage of net income, (3) by industry, and (4) by…

  5. The mutation p.E113K in the Schiff base counterion of rhodopsin is associated with two distinct retinal phenotypes within the same family

    Science.gov (United States)

    Reiff, Charlotte; Owczarek-Lipska, Marta; Spital, Georg; Röger, Carsten; Hinz, Hebke; Jüschke, Christoph; Thiele, Holger; Altmüller, Janine; Nürnberg, Peter; Da Costa, Romain; Neidhardt, John

    2016-01-01

    The diagnoses of retinitis pigmentosa (RP) and stationary night blindness (CSNB) are two distinct clinical entities belonging to a group of clinically and genetically heterogeneous retinal diseases. The current study focused on the identification of causative mutations in the RP-affected index patient and in several members of the same family that reported a phenotype resembling CSNB. Ophthalmological examinations of the index patient confirmed a typical form of RP. In contrast, clinical characterizations and ERGs of another affected family member showed the Riggs-type CSNB lacking signs of RP. Applying whole exome sequencing we detected the non-synonymous substitution c.337G > A, p.E113 K in the rhodopsin (RHO) gene. The mutation co-segregated with the diseases. The identification of the pathogenic variant p.E113 K is the first description of a naturally-occurring mutation in the Schiff base counterion of RHO in human patients. The heterozygous mutation c.337G > A in exon 1 was confirmed in the index patient as well as in five CSNB-affected relatives. This pathogenic sequence change was excluded in a healthy family member and in 199 ethnically matched controls. Our findings suggest that a mutation in the biochemically well-characterized counterion p.E113 in RHO can be associated with RP or Riggs-type CSNB, even within the same family. PMID:27812022

  6. Density-functional theory for fluid mixtures of charged chain particles and spherical counterions in contact with charged hard wall: Adsorption, double layer capacitance, and the point of zero charge.

    Science.gov (United States)

    Pizio, O; Bucior, K; Patrykiejew, A; Sokołowski, S

    2005-12-01

    We consider a density-functional theory to describe nonuniform fluids composed of chain molecules, containing a charged segment each, and spherical counterions. The chain molecules are modeled as freely jointed chains of hard spheres, the counterions are oppositely charged spheres of the same diameter as all segments of chain molecules. The theory is applied to study the structure of adsorbed layers, the excess adsorption isotherms, the capacitance of the double layer, and the potential of the zero charge. We show that all electric properties are strongly dependent on the length of the chain molecules. Moreover, these properties are also dependent on the position of the charged segment in the chain.

  7. Electrostatic contribution to DNA condensation - application of 'energy minimization' in a simple model in strong Coulomb coupling regime

    CERN Document Server

    Mukherjee, Arup K

    2011-01-01

    Bending of DNA from a straight rod to a circular form in presence of any of the mono-, di-, tri- or tetravalent counterions has been simulated in strong Coulomb coupling environment employing a previously developed energy minimization simulation technique. The inherent characteristics of the simulation technique allow monitoring the required electrostatic contribution to the bending. The curvature of the bending has been found to play crucial roles in facilitating electrostatic attractive potential energy. The total electrostatic potential energy has been found to decrease with bending which indicates that bending a straight DNA to a circular form or to a toroidal form in presence of neutralizing counterions is energetically favorable and practically is a spontaneous phenomenon.

  8. Hierarchical contribution of river–ocean connectivity, water chemistry, hydraulics, and substrate to the distribution of diadromous snails in Puerto Rican streams.

    Science.gov (United States)

    Juan F. Blanco; Frederick N. Scatena

    2006-01-01

    Diadromous faunas dominate most tropical coastal streams and rivers, but the factors controlling their distribution are not well understood. Our study documents abiotic variables controlling the distribution and abundance of the diadromous snail Neritina virginea (Gastropoda:Neritidae) in the Caribbean island of Puerto Rico. An intensive survey of N. virginea density...

  9. Effects of counterions of colorful sandwich-type zinc(II) 4‧-phenyl-terpyridine compounds on photoluminescent and thermal properties

    Science.gov (United States)

    Zhang, Yongqiang; Zhou, Peng; Liang, Baohuan; Huang, Ling; Zhou, Yanling; Ma, Zhen

    2017-10-01

    Reactions between 4‧-phenyl-terpyridine (L) and several Zn(II) salts (p-toluenesulfonate, nitrate, trifluoromethane sulfonate or hexafluoroantimonate) led to the formation of the complexes [ZnL2](p-OSO2PhCH3)2 (1), [ZnL2](NO3)2 (2), [ZnL2](SO3CF3)2 (3) and [ZnL2](SbF6)2 (4), which were characterized by IR, 1H NMR, elemental analysis, UV-vis spectroscopies and single crystal X-ray diffraction, along with their TG-DTA thermal and photoluminescent properties. The four compounds show mononuclear Zn(II) structures with hexacoordinated, irregular ZnN6 octahedron geometries. Their colours and photo-luminescent properties have changed regularly depending on the counterions of the compounds.

  10. Simultaneous Counter-Ion Co-Deposition a Technique Enabling Matrix Isolation Spectroscopy Studies Using Low-Energy Beams of Mass-Selected Ions

    Science.gov (United States)

    Ludwig, Ryan M.; Moore, David T.

    2014-06-01

    Matrix isolation spectroscopy was first developed in Pimentel's group during the 1950's to facilitate spectroscopic studies of transient species. Cryogenic matrices of condensed rare gases provide an inert chemical environment with facile energy dissipation and are transparent at all wavelengths longer than vacuum UV, making them ideal for studying labile and reactive species such as radicals, weakly bound complexes, and ions. Since frozen rare gases are poor electrolytes, studies of ions require near-equal populations of anions and cations in order to stabilize the number densities required for spectroscopic experiments. Many techniques for generation of ions for using in matrix isolation studies satisfy this criterion intrinsically, however when ion beams generated in external sources are deposited, the counter-ions typically arise via secondary processes that are at best loosely controlled. It has long been recognized that it would be desirable to stabilize deposition of mass-selected ions generated in an external source using simultaneous co-deposition of a beam of counter-ions, however previous attempts to achieve this have been reported as unsuccessful. The Moore group at Lehigh has demonstrated successful experiments of this type, using mass-selected anions generated from a metal cluster source, co-deposited with a balanced current of cations generated in a separate electron ionization source. This talk will focus on the details of the technique, and present some results from proof-of-concept studies on anionic copper carbonyl complexes formed in argon matrices following co-deposition of Cu- with Ar+ or Kr+. Funding support from NSF CAREER Award CHE-0955637 is gratefully acknowledged. Whittle et al., J. Chem. Phys. 22, p.1943 (1954); Becker et al., J. Chem. Phys. 25, p.224 (1956). Godbout et al., J. Chem. Phys. 96, p.2892 (1996). Sabo et al., Appl. Spectrosc. 45, p. 535 (1991).

  11. Modelling the spatial distribution of endemic Caesalpinioideae in Central Africa, a contribution to the evaluation of actual protected areas in the region

    DEFF Research Database (Denmark)

    Ndayishimiye, Joël; Greve, Michelle; Stoffelen, P.

    2012-01-01

    variables (soil, elevation, and slope). Environmental variables and species occurrence data were obtained respectively from the WorldClim database and from herbarium specimens kept at the National Botanic Garden of Belgium and the Université Libre de Bruxelles. Our results suggest that the distribution...

  12. Modelling the spatial distribution of endemic Caesalpinioideae in Central Africa, a contribution to the evaluation of actual protected areas in the region

    DEFF Research Database (Denmark)

    Ndayishimiye, Joël; Greve, Michelle; Stoffelen, P.

    2012-01-01

    Understanding why some regions have higher levels of diversity and which factors are driving the occurrence of species in a particular area is crucial for environmental management and for the development of species conservation strategies. In this study, we studied seven species of the Caesalpini......Understanding why some regions have higher levels of diversity and which factors are driving the occurrence of species in a particular area is crucial for environmental management and for the development of species conservation strategies. In this study, we studied seven species...... of the Caesalpinioideae that are endemic in Central Africa (Democratic Republic of the Congo, Burundi and Rwanda). The objectives of this study were to identify the environmental factors that constrain their distribution, to determine the potential areas where each species could be present, to assess the current...... conservation status of each species and to evaluate how well the species are protected by the protected areas in the region. Distributions were analyzed and potential distributions predicted using the Maxent species distribution algorithm with climatic (precipitation and temperature) and non-climatic predictor...

  13. Effect of diamagnetic contribution of water on harmonics distribution in a dilute solution of iron oxide nanoparticles measured using high-T{sub c} SQUID magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Saari, Mohd Mawardi, E-mail: en19463@s.okayama-u.ac.jp; Tsukamoto, Yuya; Kusaka, Toki; Ishihara, Yuichi; Sakai, Kenji; Kiwa, Toshihiko; Tsukada, Keiji

    2015-11-15

    The magnetization curve of iron oxide nanoparticles in low-concentration solutions was investigated by a highly sensitive high-T{sub c} superconducting quantum interference device (SQUID) magnetometer. The diamagnetic contribution of water that was used as the carrier liquid was observed in the measured magnetization curves in the high magnetic field region over 100 mT. The effect of the diamagnetic contribution of water on the generation of harmonics during the application of AC and DC magnetic fields was simulated on the basis of measured magnetization curves. Although the diamagnetic effect depends on concentration, a linear relation was observed between the detected harmonics and concentration in the simulated and measured results. The simulation results suggested that improvement could be expected in harmonics generation because of the diamagnetic effect when the iron concentration was lower than 72 μg/ml. The use of second harmonics with an appropriate bias of the DC magnetic field could be utilized for realization of a fast and highly sensitive detection of magnetic nanoparticles in a low-concentration solution. - Highlights: • We measured iron oxide nanoparticles solutions using a high-T{sub c} SQUID magnetometer. • Diamagnetic contribution of water in diluted solutions was observed. • Improvement in harmonics generation due to diamagnetism of water could be expected. • Linear relation between harmonics and concentration in diluted solutions was shown. • Detection using second harmonics showed high sensitivity.

  14. Success of Senegal's first nationwide distribution of long-lasting insecticide-treated nets to children under five - contribution toward universal coverage

    Directory of Open Access Journals (Sweden)

    Diouf Mame

    2011-04-01

    Full Text Available Abstract Background In 2009, the first national long-lasting insecticide-treated net (LLIN distribution campaign in Senegal resulted in the distribution of 2.2 million LLINs in two phases to children aged 6-59 months. Door-to-door teams visited all households to administer vitamin A and mebendazole, and to give a coupon to redeem later for an LLIN. Methods A nationwide community-based two-stage cluster survey was conducted, with clusters selected within regions by probability proportional to size sampling, followed by GPS-assisted mapping, simple random selection of households in each cluster, and administration of a questionnaire using personal digital assistants (PDAs. The questionnaire followed the Malaria Indicator Survey format, with rosters of household members and bed nets, and questions on campaign participation. Results There were 3,280 households in 112 clusters representing 33,993 people. Most (92.1% guardians of eligible children had heard about the campaign, the primary sources being health workers (33.7%, neighbours (26.2%, and radio (22.0%. Of eligible children, 82.4% received mebendazole, 83.8% received vitamin A, and 75.4% received LLINs. Almost all (91.4% LLINs received during the campaign remained in the household; of those not remaining, 74.4% had been given away and none were reported sold. At least one insecticide-treated net (ITN was present in 82.3% of all households, 89.2% of households with a child Conclusions The nationwide integrated LLIN distribution campaign allowed household ITN ownership of one or more ITNs to surpass the RBM target of 80% set for 2010, though additional distribution strategies are needed to reach populations missed by the targeted campaign and to reach the universal coverage targets of one ITN per sleeping space and 80% of the population using an ITN.

  15. Pseudo-nitzschia species on the Catalan coast: characterization and contribution to the current knowledge of the distribution of this genus in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Sonia Quijano-Scheggia

    2010-04-01

    Full Text Available Proliferations of the genus Pseudo-nitzschia recur along the Catalan coast (NW Mediterranean throughout the year. The establishment of 58 clonal cultures facilitated morphological studies with scanning electron microscopy (SEM and ITS 5.8S rDNA sequence characterization. Moreover, strains of each species were examined with respect to sexual compatibility and toxicity. The results of the morphological and phylogenetic studies confirmed nine species of the genus Pseudo-nitzschia: P. brasiliana, P. calliantha, P. delicatissima clade A/del 2, P. arenysensis, P. fraudulenta, P. galaxiae, P. linea, P. multistriata and P. pungens clade I. Moreover, two Pseudo-nitzschia species, P. caciantha and P. cf mannii, could only be identified following SEM analysis of their morphology. None of the cultured strains of Pseudo-nitzschia analyzed produced domoic acid in amounts above the limit of detection. The current distributions of the Pseudo-nitzschia species in the Mediterranean Sea were plotted on maps, which led to the following observations: i diversity within this genus is much greater than previously considered, ii some species have a broad distribution (e.g. P. calliantha, iii whereas the distribution of others is narrowly restricted (e.g. P. pungens clade I. Moreover, this study reports the first detection of P. linea in the Mediterranean Sea and is the first description of P. galaxiae and P. cf mannii along the Catalan coast. Morphological studies coupled with molecular biological characterization, mating tests and biogeographic distribution analyses provide a critical theoretical basis for testing and/or implementing the current phylogenetic framework in the genus Pseudo-nitzschia.

  16. CRF receptor 1 antagonism and brain distribution of active components contribute to the ameliorative effect of rikkunshito on stress-induced anorexia.

    Science.gov (United States)

    Mogami, Sachiko; Sadakane, Chiharu; Nahata, Miwa; Mizuhara, Yasuharu; Yamada, Chihiro; Hattori, Tomohisa; Takeda, Hiroshi

    2016-06-08

    Rikkunshito (RKT), a Kampo medicine, has been reported to show an ameliorative effect on sustained hypophagia after novelty stress exposure in aged mice through serotonin 2C receptor (5-HT2CR) antagonism. We aimed to determine (1) whether the activation of anorexigenic neurons, corticotropin-releasing factor (CRF), and pro-opiomelanocortin (POMC) neurons, is involved in the initiation of hypophagia induced by novelty stress in aged mice; (2) whether the ameliorative effect of RKT is associated with CRF and POMC neurons and downstream signal transduction; and (3) the plasma and brain distribution of the active components of RKT. The administration of RKT or 5-HT2CR, CRF receptor 1 (CRFR1), and melanocortin-4 receptor antagonists significantly restored the decreased food intake observed in aged male C57BL/6 mice in the early stage after novelty stress exposure. Seven components of RKT exhibited antagonistic activity against CRFR1. Hesperetin and isoliquiritigenin, which showed antagonistic effects against both CRFR1 and 5-HT2CR, were distributed in the plasma and brain of male Sprague-Dawley rats after a single oral administration of RKT. In conclusion, the ameliorative effect of RKT in this model is assumed to be at least partly due to brain-distributed active components possessing 5-HT2CR and CRFR1 antagonistic activities.

  17. Physiological mechanisms of dehydration tolerance contribute to the invasion potential of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) relative to its less widely distributed congeners.

    Science.gov (United States)

    Weldon, Christopher W; Boardman, Leigh; Marlin, Danica; Terblanche, John S

    2016-01-01

    The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) is a highly invasive species now with an almost cosmopolitan distribution. Two other damaging, polyphagous and closely-related species, the marula fruit fly, Ceratitis cosyra (Walker), and the Natal fly, Ceratitis rosa Karsch, are not established outside of sub-Saharan Africa. In this study, adult water balance traits and nutritional body composition were measured in all three species at different temperatures and levels of relative humidity to determine whether tolerance of water stress may partially explain their distribution. Adult C. capitata exhibited higher desiccation resistance than C. rosa but not C. cosyra. Desiccation resistance of C. capitata was associated with lower rates of water loss under hot and dry conditions, higher dehydration tolerance, and higher lipid reserves that were catabolised during water stress. In comparison with C. capitata, C. cosyra and C. rosa lost water at significantly higher rates under hot, dry conditions, and did not catabolise lipids or other sources of metabolic water during water stress. These results suggest that adult physiological traits permitting higher tolerance of water stress play a role in the success of C. capitata, particularly relative to C. rosa. The distribution of C. cosyra is likely determined by the interaction of temperature with water stress, as well as the availability of suitable hosts for larval development.

  18. Electrostatic contribution to DNA condensation-application of 'energy minimization' in a simple model in the strong Coulomb coupling regime

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Arup K, E-mail: akmukherjee11@hotmail.com [Department of Physics, Chancellor College, University of Malawi, Box 280, Zomba (Malawi)

    2011-08-17

    The process of bending of straight DNA to a circular form in the presence of any of the mono-, di-, tri- or tetravalent counterions has been simulated in a strong Coulomb coupling environment, employing a previously developed energy minimization simulation technique. The inherent characteristics of the simulation technique allow the monitoring of the required electrostatic contribution to the bending. The curvature of the bending has been found to play a crucial role in facilitating the electrostatic attractive potential energy. The total electrostatic potential energy has been found to decrease with bending, which indicates that bending straight DNA to a circular form or to a toroidal form in the presence of neutralizing counterions is energetically favourable and is practically a spontaneous phenomenon.

  19. A fingerprinting mixing model approach to generate uniformly representative solutions for distributed contributions of sediment sources in a Pyrenean drainage basin

    Science.gov (United States)

    Palazón, Leticia; Gaspar, Leticia; Latorre, Borja; Blake, Will; Navas, Ana

    2014-05-01

    Spanish Pyrenean reservoirs are under pressure from high sediment yields in contributing catchments. Sediment fingerprinting approaches offer potential to quantify the contribution of different sediment sources, evaluate catchment erosion dynamics and develop management plans to tackle the reservoir siltation problems. The drainage basin of the Barasona reservoir (1509 km2), located in the Central Spanish Pyrenees, is an alpine-prealpine agroforest basin supplying sediments to the reservoir at an annual rate of around 350 t km-2 with implications for reservoir longevity. The climate is mountain type, wet and cold, with both Atlantic and Mediterranean influences. Steep slopes and the presence of deep and narrow gorges favour rapid runoff and large floods. The ability of geochemical fingerprint properties to discriminate between the sediment sources was investigated by conducting the nonparametric Kruskal-Wallis H-test and a stepwise discriminant function analysis (minimization of Wilk's lambda). This standard procedure selects potential fingerprinting properties as optimum composite fingerprint to characterize and discriminate between sediment sources to the reservoir. Then the contribution of each potential sediment source was assessed by applying a Monte Carlo mixing model to obtain source proportions for the Barasona reservoir sediment samples. The Monte Carlo mixing model was written in C programming language and designed to deliver a user-defined number possible solutions. A Combinatorial Principals method was used to identify the most probable solution with associated uncertainty based on source variability. The unique solution for each sample was characterized by the mean value and the standard deviation of the generated solutions and the lower goodness of fit value applied. This method is argued to guarantee a similar set of representative solutions in all unmixing cases based on likelihood of occurrence. Soil samples for the different potential sediment

  20. The contribution of off-shell gluons to the structure functions F{sub 2} and F{sub L}{sup c} and the unintegrated gluon distributions

    Energy Technology Data Exchange (ETDEWEB)

    Kotikov, A.V. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lipatov, A.V. [Department of Physics, M.V. Lomonosov Moscow State University, 119899 Moscow (Russian Federation); Parente, G. [Departamento de Fisica de Particulas, Universidade de Santiago de Compostela, 15706 Santiago de Compostela (Spain); Zotov, N.P. [D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, 119899 Moscow (Russian Federation)

    2002-11-01

    We calculate the perturbative parts of the structure functions F{sub 2}{sup c} and F{sub L}{sup c} for a gluon target having non-zero transverse momentum squared at order {alpha}{sub s}. The results of the double convolution (with respect to the Bjorken variable x{sub B} and the transverse momentum) of the perturbative part and the unintegrated gluon densities are compared with the HERA experimental data for F{sub 2}{sup c}. The contribution from the F{sub L}{sup c} structure function ranges in 10-30% of that of F{sub 2}{sup c} at the kinematical range of the HERA experiments. (orig.)

  1. Integrating petrography, mineralogy and hydrochemistry to constrain the influence and distribution of groundwater contributions to baseflow in poorly productive aquifers: insights from Gortinlieve catchment, Co. Donegal, NW Ireland.

    Science.gov (United States)

    Caulfield, John; Chelliah, Merlyn; Comte, Jean-Christophe; Cassidy, Rachel; Flynn, Raymond

    2014-12-01

    Identifying groundwater contributions to baseflow forms an essential part of surface water body characterisation. The Gortinlieve catchment (5 km(2)) comprises a headwater stream network of the Carrigans River, itself a tributary of the River Foyle, NW Ireland. The bedrock comprises poorly productive metasediments that are characterised by fracture porosity. We present the findings of a multi-disciplinary study that integrates new hydrochemical and mineralogical investigations with existing hydraulic, geophysical and structural data to identify the scales of groundwater flow and the nature of groundwater/bedrock interaction (chemical denudation). At the catchment scale, the development of deep weathering profiles is controlled by NE-SW regional scale fracture zones associated with mountain building during the Grampian orogeny. In-situ chemical denudation of mineral phases is controlled by micro- to meso-scale fractures related to Alpine compression during Palaeocene to Oligocene times. The alteration of primary muscovite, chlorite (clinochlore) and albite along the surfaces of these small-scale fractures has resulted in the precipitation of illite, montmorillonite and illite-montmorillonite clay admixtures. The interconnected but discontinuous nature of these small-scale structures highlights the role of larger scale faults and fissures in the supply and transportation of weathering solutions to/from the sites of mineral weathering. The dissolution of primarily mineral phases releases the major ions Mg, Ca and HCO3 that are shown to subsequently form the chemical makeup of groundwaters. Borehole groundwater and stream baseflow hydrochemical data are used to constrain the depths of groundwater flow pathways influencing the chemistry of surface waters throughout the stream profile. The results show that it is predominantly the lower part of the catchment, which receives inputs from catchment/regional scale groundwater flow, that is found to contribute to the

  2. Characteristics of Dew Formation and Distribution, and Its Contribution to the Surface Water Budget in a Semi-arid Region in China

    Science.gov (United States)

    Zhang, Qiang; Wang, Sheng; Yang, Fu-Lin; Yue, Ping; Yao, Tong; Wang, Wen-Yu

    2015-02-01

    Observations in the semi-arid Loess Plateau area of north-west China are utilized to reveal the characteristics and variations in the seasonal distribution of dewfall (frost) and the influence of micrometeorology, precipitation, and other weather conditions. Precipitation is the dominant water source in the Loess Plateau; however, non-rainfall water accounts for 13 % of the total land-surface water source. Dew is the second largest non-rainfall component next only to soil adsorption water. Observations show that dew (frost) occurrence is likely to occur when an inversion occurs between the heights of 1 and 4 m with a temperature difference of 0.25 K, surface wind speed of 1.5 m s, and surface relative humidity greater than 80 %.

  3. Quantitative X-ray pair distribution function analysis of nanocrystalline calcium silicate hydrates: a contribution to the understanding of cement chemistry

    Science.gov (United States)

    Grangeon, Sylvain; Baronnet, Alain; Marty, Nicolas; Poulain, Agnieszka; Elkaïm, Erik; Roosz, Cédric; Gaboreau, Stéphane; Henocq, Pierre; Claret, Francis

    2017-01-01

    The structural evolution of nanocrystalline calcium silicate hydrate (C–S–H) as a function of its calcium to silicon (Ca/Si) ratio has been probed using qualitative and quantitative X-ray atomic pair distribution function analysis of synchrotron X-ray scattering data. Whatever the Ca/Si ratio, the C–S–H structure is similar to that of tobermorite. When the Ca/Si ratio increases from ∼0.6 to ∼1.2, Si wollastonite-like chains progressively depolymerize through preferential omission of Si bridging tetrahedra. When the Ca/Si ratio approaches ∼1.5, nanosheets of portlandite are detected in samples aged for 1 d, while microcrystalline portlandite is detected in samples aged for 1 year. High-resolution transmission electron microscopy imaging shows that the tobermorite-like structure is maintained to Ca/Si > 3.

  4. Ligand and counterion control of Ag(I) architectures: assembly of a {Ag8} ring cluster mediated by hydrophobic and Ag...Ag interactions.

    Science.gov (United States)

    Fielden, John; Long, De-liang; Slawin, Alexandra M Z; Kögerler, Paul; Cronin, Leroy

    2007-10-29

    A strategy combining ligand design and counterion variation has been used to investigate the assembly of silver(I) complexes. As a result, dinuclear, octanuclear, and polymeric silver(I) species have been synthesized by complexation of the rigid aliphatic amino ligands cis-3,5-diamino-trans-hydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and cis-3,5-diamino-trans-tert-butyldimethylsilylanyloxycyclohexane (DATC) with silver(I) triflate, nitrate, and perchlorate. The compositions of these aggregates, established by X-ray crystallography and elemental analysis, are [{Ag(DAHC)}2](CF3SO3)2 (1), [{Ag(DAMC)}2](CF3SO3)2 (2), [{Ag(DAMC)}2](NO3)2 (3), [{Ag(DATC)}6{Ag(DAHC)}2](NO3)8 (4), and [{Ag(DATC}n](NO3)n (5), where the DAHC present in 4 is formed by in situ hydrolysis of the acid labile silyl ether group. The type of aggregate formed depends both upon the noncoordinating O-substituent of the ligand and the (also noncoordinating) counterion, with the normal preference of the ligand topology for forming Ag2L2 structures being broken by introduction of the bulky, lipophilic O-tert-butyldimethylsilyl (TBDMS) group. Of particular note is the octanuclear silver ring structure 4, which is isolated only when both the O-TBDMS group and the nitrate counteranion are present and is formed from four Ag2L2 dimers connected by Ag...Ag and hydrogen-bonding interactions. Diffusion rate measurement of this {Ag8} complex by 1H NMR (DOSY) indicates dissociation in CD3OD and CD3CN, showing that this supramolecular ring structure is formed upon crystallization, and establishing a qualitative limit to the strength of Ag...Ag interactions in solution. When solutions of the {Ag8} cluster in methanol are kept for several days though, a new UV-vis absorption is observed at around 430 nm, consistent with the formation of silver nanoparticles.

  5. The distribution of organic material and its contribution to the micro-topography of particles from wettable and water repellent soils

    Science.gov (United States)

    Bryant, Rob; Cheng, Shuying; Doerr, Stefan H.; Wright, Chris J.; Bayer, Julia V.; Williams, Rhodri P.

    2010-05-01

    Organic coatings on mineral particles will mask the physic-chemical properties of the underlying mineral surface. Surface images and force measurements obtained using atomic force microscopy (AFM) provide information about the nature of and variability in surfaces properties at the micro- to nano-scale. As AFM technology and data processing advance it is anticipated that a significant amount of information will be obtained simultaneously from individual contacts made at high frequency in non-contact or tapping mode operation. For present purposes the surfaces of model materials (smooth glass surfaces and acid-washed sand (AWS)) provide an indication of the dependency of the so-called AFM phase image on the topographic image (which is obtained synoptically). Pixel wise correlation of these images reveals how the modulation of an AFM probe is affected when topographic features are encountered. Adsorption of soil-derived humic acid (HA) or lecithin (LE), used here as an example for natural organic material, on these surfaces provides a soft and compliant, albeit partial, covering on the mineral which modifies the topography and the response of an AFM tip as it partially indents the soft regions (which contributes depth to the phase image). This produces a broadening on the data domain in the topographic/phase scatter diagram. Two dimensional classifications of these data, together with those obtained from sand particles drawn from water repellent and wettable soils, suggest that these large adsorbate molecules appear to have little preference to attach to particular topographic features or elevations. It appears that they may effectively remain on the surface at the point of initial contact. If organic adsorbates present a hydrophobic outer surface, then it seems possible that elevated features will not be immune from this and provide scope for a local, albeit, small contribution to the expression of super-hydrophobicity. It is therefore speculated here that the water

  6. Anion-π, lone pair-π and π-π interactions in VO(O2)+ complexes with one dipicolinato(2-)-N,O,O ligand and bearing picolinamidium, nicotinamidium or phenanthrolinium as counterions

    Science.gov (United States)

    Gyepes, Róbert; Pacigová, Silvia; Tatiersky, Jozef; Sivák, Michal

    2013-06-01

    From the V2O5sbnd H2O2sbnd H2dipic-nica/pa/phen-H2O/H2Osbnd CH3CN reaction systems (H2dipic = dipicolinic acid, nica = nicotinamide, pa = picolinamide, phen = 1,10-phenanthroline), three monoperoxidovanadium(V) complexes have been synthesized and structurally characterized: (Hpa)[VO(O2)(dipic)(H2O)]ṡH2O (1), (Hnica)[VO(O2)(dipic)(H2O)] (2) and (Hphen)[VO(O2)(dipic)(H2O)]ṡH2O (3). The organic counterions in 1-3 are protonated on the aromatic nitrogen atoms, whereas the dipicolinato(2-) (=dipic) ligand adopts a tridentate chelating coordination mode in all three complexes. The NOO donor atoms of dipic occupy the three equatorial positions of the characteristic distorted pentagonal bipyramid around the central vanadium atom. The aqua ligand is located in the apical position trans to the short Vtbnd O(oxido) bond. In addition to electrostatic cation-anion interactions, the supramolecular architecture of the title complexes is formed by: (i) a network of Dsbnd H⋯O (D = N, O and C) hydrogen bonds, (ii) π-π interactions between offset pyridine rings of dipic (in 1 and 2) as well as between the rings of Hpa+, Hnica+ or Hphen+, (iii) anion-π interactions (in 1 and 3) between the oxygen atoms of the COO- group and rings of the dipic ligands, and (iv) the rarely recognized lone pair-π interaction between the carboxamide oxygen atoms of Hpa+ and pyridine rings in 1, as well as between the oxygen atoms from crystal water molecules and the pyridine rings of Hphen+ in 3. The anion-π and lone pair-π interactions were studied more in detail by DFT. A common feature for both these interactions was the lack of significant covalent contributions to the attraction between the respective partners. 51V NMR spectra of the acidic aqueous solutions of 1-3 showed that the structure of the complex anion is for 2 and 3 maintained even after dissolution (single shift δV = -597 ppm), whereas 1 partially decomposes with formation of monoperoxidovanadium(V) species: [VO(O2)(H2O

  7. Investigation of the 3D temperature distribution patterns above the Antarctic Peninsula using remote sensing data - A contribution for polar climate monitoring

    Science.gov (United States)

    Wachter, Paul; Höppner, Kathrin; Jacobeit, Jucundus; Diedrich, Erhard

    2015-04-01

    West Antarctica and the Antarctic Peninsula are in the focus of current studies on a changing environment and climate of the polar regions. A recently founded Junior Researchers Group at the German Aerospace Center (DLR) is studying changing processes in cryosphere and atmosphere above the Antarctic Peninsula. It is the aim of the group to make use of long-term remote sensing data sets of the land and ice surfaces and the atmosphere in order to characterize environmental changes in this highly sensitive region. One of the PhD projects focuses on the investigation of the 3D temperature distribution patterns above the Antarctic Peninsula. Temperature data sets ranging from MODIS land surface temperatures up to middle atmosphere data of AURA/MLS will be evaluated over the last approx. 12 years. This 3-dimensional view allows comprehensive investigations of the thermal structure and spatio-temporal characteristics of the southern polar atmosphere. Tropospheric data sets will be analyzed by multivariate statistical methods and will allow the identification of dominant atmospheric circulation patterns as well as their temporal variability. An overview of the data sets and first results will be presented.

  8. Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to late Pliocene/early Pleistocene climate cooling

    Directory of Open Access Journals (Sweden)

    J. Etourneau

    2012-03-01

    Full Text Available The global late Pliocene/early Pleistocene cooling (~3.0–2.0 million years ago, Ma concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela Upwelling System (BUS, off Namibia, where it is known as the Matuyama Diatom Maximum (MDM. Our study focuses on a new diatom silicon isotope (δ30Si record covering the MDM in the BUS. Unexpectedly, the variations in δ30Si signal follow biogenic opal content, whereby the highest δ30Si values correspond to the highest biogenic opal content. We interpret the higher δ30Si values during the MDM as a result of a stronger degree of silicate utilization in the surface waters caused by high productivity of mat-forming diatom species. This was most likely promoted by weak upwelling intensity dominating the BUS during the Plio/Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0–2.7 Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to late Pliocene/early Pleistocene cooling.

  9. Capillary electrophoresis procedure for the simultaneous analysis and stoichiometry determination of a drug and its counter-ion by using dual-opposite end injection and contactless conductivity detection: application to labetalol hydrochloride.

    Science.gov (United States)

    Nehmé, Reine; Lascaux, Adrien; Delépée, Raphaël; Claude, Bérengère; Morin, Philippe

    2010-03-24

    In this work, a capillary electrophoresis (CE) procedure was developed for the simultaneous determination of a pharmaceutical drug and its counter-ion, namely labetalol hydrochloride. For this purpose, an uncoated fused-silica capillary, a low conductivity background electrolyte (BGE) and a capacitively coupled contactless conductivity detector (C(4)D) were employed. This detection system is highly sensitive and enables detection of inorganic as well as organic ions unlike with direct UV detection. Moreover, to be able to simultaneously analyze the cationic drug (labetalol(+)) and its anionic counter-ion (Cl(-)) in the same electrophoretic run without the need of a coated capillary, a dual-opposite end injection was performed. In this technique, the sample is hydrodynamically injected into both ends of the capillary. This method is simple and easy to perform since the different injection steps are automated by the CE software. This novel CE-C(4)D procedure with dual-opposite end injection has been successfully validated and applied for the analysis of chloride content in an adrenergic antagonist (labetalol hydrochloride). Thus, the hereby developed method has been shown to enable fast (analysis time<10 min), precise (repeatability of migration times<0.7% and of corrected-peak areas < 3.3%; n=6) and rugged analyses for the simultaneous determination of a pharmaceutical drug and its counter-ion. Copyright 2010 Elsevier B.V. All rights reserved.

  10. A Density Functional Theory Based Protocol to Compute the Redox Potential of Transition Metal Complex with the Correction of Pseudo-Counterion: General Theory and Applications.

    Science.gov (United States)

    Matsui, Toru; Kitagawa, Yasutaka; Shigeta, Yasuteru; Okumura, Mitsutaka

    2013-07-09

    We propose an accurate scheme to evaluate the redox potential of a wide variety of transition metal complexes by adding a charge-dependent correction term for a counterion around the charged complexes, which is based on Generalized Born theory, to the solvation energy. The mean absolute error (MAE) toward experimental redox potentials of charged complexes is considerably reduced from 0.81 V (maximum error 1.22 V) to 0.22 V (maximum error 0.50 V). We found a remarkable exchange-correlation functional dependence on the results rather than the basis set ones. The combination of Wachters+f (for metal) and 6-31++G(d,p) (for other atoms) with the B3LYP functional gives the least MAE 0.15 V for the test complexes. This scheme is applicable to other solvents, and heavier transition metal complexes such as M1(CO)5(pycn) (M1 = Cr, Mo, W), M2(mnt)2 (M2 = Ni, Pd, Pt), and M3(bpy)3 (M3 = Fe, Ru, Os) with the same quality.

  11. Mobilization of soluble and dispersible lead, arsenic, and antimony in a polluted, organic-rich soil - effects of pH increase and counterion valency.

    Science.gov (United States)

    Klitzke, Sondra; Lang, Friederike

    2009-01-01

    Liming is a common technique suggested for the stabilization of shooting range sites. We investigated the effect of an increase in pH on the mobilization of soluble and dispersible (colloidal) Pb, As, and Sb. Our hypothesis was that the addition of divalent cations counteracts the pH-induced mobilization of soluble and colloidal metal(loid)s. We determined soluble (operationally defined as the fraction < 10 nm obtained after centrifugation) and dispersible (filter cut-off 1200 nm) As, Pb, Sb, Fe, and C(org) concentrations in the filtered suspensions of batch extracts of topsoil samples (C(org): 8%) from a former shooting range site following a pH increase to values between 3.5 and 7 by adding a monovalent (KOH) or a divalent (Ca(OH)(2)) base. In the Ca(OH)(2)-treated samples, dissolved metal(loid) concentrations were 62 to 98% lower than those titrated with KOH to similar pH. Similarly, Ca reduced the concentration of dispersible Pb by 95%, but had little or no impact on dispersible As and Sb. We conclude that the counterion valency controls the mobility of metal(loid)s by affecting the mobility and sorption capacity of the sorbents (e.g., colloids, organic matter).

  12. Cytogenetic Reconstruction of Gamma-Ray Doses Delivered to Atomic Bomb Survivors: Dealing with Wide Distributions of Photon Energies and Contributions from Hematopoietic Stem/Progenitor Cells.

    Science.gov (United States)

    Nakamura, Nori; Hirai, Yuko; Kodama, Yoshiaki; Hamasaki, Kanya; Cullings, Harry M; Cordova, Kismet A; Awa, Akio

    2017-08-11

    Retrospective estimation of the doses received by atomic bomb (A-bomb) survivors by cytogenetic methods has been hindered by two factors: One is that the photon energies released from the bomb were widely distributed, and since the aberration yield varies depending on the energy, the use of monoenergetic (60)Co gamma radiation to construct a calibration curve may bias the estimate. The second problem is the increasing proportion of newly formed lymphocytes entering into the lymphocyte pool with increasing time intervals since the exposures. These new cells are derived from irradiated precursor/stem cells whose radiosensitivity may differ from that of blood lymphocytes. To overcome these problems, radiation doses to tooth enamel were estimated using the electron spin resonance (ESR; or EPR, electron paramagnetic resonance) method and compared with the cytogenetically estimated doses from the same survivors. The ESR method is only weakly dependent on the photon energy and independent of the years elapsed since an exposure. Both ESR and cytogenetic doses were estimated from 107 survivors. The latter estimates were made by assuming that although a part of the cells examined could be lymphoid stem or precursor cells at the time of exposure, all the cells had the same radiosensitivity as blood lymphocytes, and that the A-bomb gamma-ray spectrum was the same as that of the (60)Co gamma rays. Subsequently, ESR and cytogenetic endpoints were used to estimate the kerma doses using individual DS02R1 information on shielding conditions. The results showed that the two sets of kerma doses were in close agreement, indicating that perhaps no correction is needed in estimating atomic bomb gamma-ray doses from the cytogenetically estimated (60)Co gamma-ray equivalent doses. The present results will make it possible to directly compare cytogenetic doses with the physically estimated doses of the survivors, which would pave the way for testing whether or not there are any systematic

  13. A novel pathway of TEF regulation mediated by microRNA-125b contributes to the control of actin distribution and cell shape in fibroblasts.

    Directory of Open Access Journals (Sweden)

    Olga Gutierrez

    Full Text Available BACKGROUND: Thyrotroph embryonic factor (TEF, a member of the PAR bZIP family of transcriptional regulators, has been involved in neurotransmitter homeostasis, amino acid metabolism, and regulation of apoptotic proteins. In spite of its relevance, nothing is known about the regulation of TEF. PRINCIPAL FINDINGS: p53-dependent genotoxic agents have been shown to be much more harmful for PAR bZIP-deficient mice as compared to wild type animals. Here we demonstrate that TEF expression is controlled by p53 through upregulation of microRNA-125b, as determined by both regulating the activity of p53 and transfecting cells with microRNA-125b precursors. We also describe a novel role for TEF in controlling actin distribution and cell shape in mouse fibroblasts. Lack of TEF is accompanied by dramatic increase of cell area and decrease of elongation (bipolarity and dispersion (multipolarity. Staining of actin cytoskeleton also showed that TEF (-/- cells are characterized by appearance of circumferential actin bundles and disappearance of straight fibers. Interestingly, transfection of TEF (-/- fibroblasts with TEF induced a wild type-like phenotype. Consistent with our previous findings, transfection of wild type fibroblasts with miR-125b promoted a TEF (-/--like phenotype, and a similar but weaker effect was observed following exogenous expression of p53. CONCLUSIONS/SIGNIFICANCE: These findings provide the first evidence of TEF regulation, through a miR-125b-mediated pathway, and describes a novel role of TEF in the maintenance of cell shape in fibroblasts.

  14. Estimating Groundwater-Age Distributions Contributing to Streams in the Fractured-Rock Terrain of the Upper Potomac River Basin, USA (Invited)

    Science.gov (United States)

    Sanford, W. E.; Fleming, B.; Pope, J.

    2013-12-01

    Base flow to individual streams has discharging groundwater with ages that vary widely between values of days to centuries or more. This distribution of ages has important repercussions for the response time of a watershed between change in land-use practices and the discharge of contaminants, such as nitrogen, to streams or coastal waterways. Lumped parameter models are frequently used to predict such watershed responses in shallow aquifers, but these usually assume homogeneous hydraulic properties. In the Chesapeake Bay watershed, however, over half of the terrain is underlain by fractured-rock, where heterogeneous hydraulic properties do not fit standard lumped-parameter model assumptions. In order to better understand the response behavior of a regional fractured-rock terrain, we developed a seven-million node, three-dimensional groundwater model of the Upper Potomac River Basin (~24,000 sq. km) using MODFLOW that includes siliciclastic, carbonate, and metamorphic rocks. Inverse modeling was undertaken to estimate regional values of hydraulic conductivity (K) using 200 water-level measurements in wells, and effective porosity using >100 environmental tracer (CFC-113, SF6, 3H, 3He) measurements from wells, springs and the Potomac River at the basin outlet. Results indicate a very strong depth-dependence of K, with values declining by 4-6 orders of magnitude within 100 m of land surface, with the bulk of the transmissivity being focused in the upper 10 m. This depth-dependent behavior has major implications for the watershed response time, as the base flows have ages that range over four orders of magnitude, as opposed to a shallow homogenous aquifer that usually has an equivalent range of less than two orders of magnitude. A tritium record from 1961-1991 in the Potomac River at the basin outflow can be reproduced by the model using advective transport and a single regional porosity value of 2-3 percent. In addition, the fit to the data can be improved at early

  15. Surfactants at Single-Walled Carbon Nanotube-Water Interface: Physics of Surfactants, Counter-Ions, and Hydration Shell

    Science.gov (United States)

    Khare, Ketan S.; Phelan, Frederick R., Jr.

    Specialized applications of single-walled carbon nanotubes (SWCNTs) require an efficient and reliable method to sort these materials into monodisperse fractions with respect to their defining metrics (chirality, length, etc.) while retaining their physical and chemical integrity. A popular method to achieve this goal is to use surfactants that individually disperse SWCNTs in water and then to separate the resulting colloidal mixture into fractions that are enriched in monodisperse SWCNTs. Recently, experiments at NIST have shown that subtle point mutations of chemical groups in bile salt surfactants have a large impact on the hydrodynamic properties of SWCNT-surfactant complexes during ultracentrifugation. These results provide strong motivation for understanding the rich physics underlying the assembly of surfactants around SWCNTs, the structure and dynamics of counter ions around the resulting complex, and propagation of these effects into the first hydration shell. Here, all-atom molecular dynamics simulations are used to investigate the thermodynamics of SWCNT-bile salt surfactant complexes in water with an emphasis on the buoyant characteristics of the SWCNT-surfactant complexes. Simulation results will be presented along with a comparison with experimental data. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.

  16. Enhanced luminescence properties of highly threaded conjugated polyelectrolytes with potassium counter-ions upon blending with poly(ethylene oxide)

    Science.gov (United States)

    Latini, Gianluca; Winroth, Gustaf; Brovelli, Sergio; McDonnell, Shane O.; Anderson, Harry L.; Mativetsky, Jeffrey M.; Samorı, Paolo; Cacialli, Franco

    2010-06-01

    The photophysics and electroluminescence (EL) of thin films of unthreaded and cyclodextrin-encapsulated poly(4,4'-diphenylenevinylene) (PDV) with potassium countercations, blended with poly(ethylene oxide) (PEO) are investigated as a function of the PEO concentration. We show that three main factors contribute to increasing the photoluminescence (PL) quantum efficiency as a result of suppressed intermolecular interactions, namely: the high degree of encapsulation of the polyrotaxanes, the relatively large countercation (e.g., compared to lithium), and the complexation of the rotaxanes with PEO. By facilitating cationic transport to the negative electrodes, PEO also leads to devices with enhanced electron injection and improved charge balance, whose operation therefore resembles that of "virtually unipolar" light-emitting electrochemical cells. This effect, together with the enhanced PL efficiency, leads to higher EL efficiency for both polyrotaxanes and unthreaded polymers, upon addition of the PEO. We show that the concurrent exploitation of the various strategies above lead to an overall EL efficiency that is approximately twice the value previously reported for Li-based PDV. A blueshift of the EL spectrum during the devices turn-on is also reported and analyzed in terms of interference and doping effects.

  17. Observations of Particle Organic Nitrate from Airborne and Ground Platforms in North America: Insights into Vertical and Geographical Distributions, Gas/Particle Partitioning, Losses, and Contributions to Total Particle Nitrate.

    Science.gov (United States)

    Day, D. A.; Campuzano Jost, P.; Palm, B. B.; Hu, W.; Nault, B.; Wooldridge, P. J.; Cohen, R. C.; Docherty, K. S.; Wagner, N. L.; Jimenez, J. L.

    2015-12-01

    Organic nitrate formation in the atmosphere represents a sink of NOx and a termination of the HOx/NOx­ O3-formation cycles, can act as a NOx reservoir transporting reactive nitrogen, and contributes to secondary organic aerosol (SOA) formation. However, particle organic nitrates (pRONO2) are rarely measured and thus poorly understood. We use measurements of pRONO2 and total (gas+particle) organic nitrate (totRONO2), OA, and ammonium nitrate from the DC3 and SEAC4RS aircraft and several ground campaigns to investigate vertical and geographical distributions, gas/particle partitioning, losses, and contributions to total particle nitrate (pTotNO3). Quantification with aerosol mass spectrometry is evaluated. The fraction of pTotNO3 that is pRONO2 shows a steep inverse relationship with pTotNO3, approaching 100% at low pTotNO3, primarily at rural and remote locations. pRONO2 was typically 10-30% of totRONO2 with little vertical gradient in gas/particle partitioning from the boundary layer (BL) to the upper troposphere (UT). However, pRONO2 and totRONO2 concentrations show strong vertical gradients, with a steep decrease from the top of the BL up through the residual layer. pRONO2 contribution to OA shows a moderate increase with lower OA loadings in the BL and free troposphere (~2-3% by mass of nitrate group) with higher contributions at the lowest OA (5-8%), mostly observed in the UT. In the BL, RONO2 gas/particle partitioning shows a trend with temperature, with higher particle fraction at lower temperatures, as expected from partitioning theory. However, the temperature trend is much weaker than for single compound partitioning, which may be due to a broad mixture of species. Little to no dependence of pRONO­2/OA on RH or estimated particle water was observed in the BL, suggesting that losses of pRONO2 species due to hydrolysis are too rapid to observe in this dataset and there may be a substantial fraction of pRONO2 species that are not prone to rapid hydrolysis.

  18. Competing gas-phase substitution and elimination reactions of gemini surfactants with anionic counterions by mass spectrometry. Density functional theory correlations with their bolaform halide salt models.

    Science.gov (United States)

    Aimé, Carole; Plet, Benoit; Manet, Sabine; Schmitter, Jean-Marie; Huc, Ivan; Oda, Reiko; Sauers, Ronald R; Romsted, Laurence S

    2008-11-20

    Understanding ion specific effects on the solution properties of association colloids is a major unsolved problem, and we are studying the chemistry of gemini surfactants in the gas-phase by mass spectrometry and density functional theory (DFT) to probe ion specific effects in the absence of water. Products from gas-phase fragmentation chemistry of dication-monoanion pairs, M2+X(-), of C16H33(CH3)2N+-(CH2)(n-) +N(CH3)2C16H33.2X(-) gemini surfactants were determined by using sequential collision induced dissociation mass spectrometry. The spacer length "n" was systematically varied (n = 2, 3, 4, and 6) for each counterion investigated (X(-) = F(-), Br(-), Cl(-), I(-), NO3(-), CF3CO2(-), and PF6(-)). The M2+X(-) pairs fragment into monocationic products from competing E2 and S N2 pathways that are readily quantified by tandem MS. The dominant reaction pathway depends on dication and anion structure because it switches from E2 to S N2 with decreasing anion basicity and increasing spacer length. For spacer lengths n = 4 and 6, the major S N2 product shifts from attack at methylene to methyl on the quaternary ammonium group. DFT calculations of gemini headgroup model bolaform salts, CH3(CH3)2N+-(CH2)(n-)+N(CH3)2CH3.2X(-) (X(-) = F(-), Cl(-), Br(-), and I(-), n = 2-4), primarily of activation enthalpies, DeltaH, but also of free energies and entropies for the dication-monoanion pairs, M2+X(-), provide qualitative explanations for the MS structure-reactivity patterns. DeltaH values for S N2 reactions are independent of X(-) type and spacer length, while E2 reactions show a significant increase in DeltaH with decreasing anion basicity and a modest increase with spacer length. Comparisons with the DeltaH values of model CH3CH2(CH3)3N+X(-) halides show that the second charge on the dicationic ion pairs does not significantly affect DeltaH and that the change in distance between the nucleophile and leaving group in the ground and transition states structures in S N2 reactions

  19. Prediction of (195) Pt NMR chemical shifts of dissolution products of H2 [Pt(OH)6 ] in nitric acid solutions by DFT methods: how important are the counter-ion effects?

    Science.gov (United States)

    Tsipis, Athanassios C; Karapetsas, Ioannis N

    2016-08-01

    (195) Pt NMR chemical shifts of octahedral Pt(IV) complexes with general formula [Pt(NO3 )n (OH)6 - n ](2-) , [Pt(NO3 )n (OH2 )6 - n ](4 - n) (n = 1-6), and [Pt(NO3 )6 - n  - m (OH)m (OH2 )n ](-2 + n - m) formed by dissolution of platinic acid, H2 [Pt(OH)6 ], in aqueous nitric acid solutions are calculated employing density functional theory methods. Particularly, the gauge-including atomic orbitals (GIAO)-PBE0/segmented all-electron relativistically contracted-zeroth-order regular approximation (SARC-ZORA)(Pt) ∪ 6-31G(d,p)(E)/Polarizable Continuum Model computational protocol performs the best. Excellent second-order polynomial plots of δcalcd ((195) Pt) versus δexptl ((195) Pt) chemical shifts and δcalcd ((195) Pt) versus the natural atomic charge QPt are obtained. Despite of neglecting relativistic and spin orbit effects the good agreement of the calculated δ (195) Pt chemical shifts with experimental values is probably because of the fact that the contribution of relativistic and spin orbit effects to computed σ(iso) (195) Pt magnetic shielding of Pt(IV) coordination compounds is effectively cancelled in the computed δ (195) Pt chemical shifts, because the relativistic corrections are expected to be similar in the complexes and the proper reference standard used. To probe the counter-ion effects on the (195) Pt NMR chemical shifts of the anionic [Pt(NO3 )n (OH)6 - n ](2-) and cationic [Pt(NO3 )n (OH2 )6 - n ](4 - n) (n = 0-3) complexes we calculated the (195) Pt NMR chemical shifts of the neutral (PyH)2 [Pt(NO3 )n (OH)6 - n ] (n = 1-6; PyH = pyridinium cation, C5 H5 NH(+) ) and [Pt(NO3 )n (H2 O)6 - n ](NO3 )4 - n (n = 0-3) complexes. Counter-anion effects are very important for the accurate prediction of the (195) Pt NMR chemical shifts of the cationic [Pt(NO3 )n (OH2 )6 - n ](4 - n) complexes, while counter-cation effects are less important for the anionic [Pt(NO3 )n (OH)6

  20. Plant STAND P-loop NTPases: a current perspective of genome distribution, evolution, and function : Plant STAND P-loop NTPases: genomic organization, evolution, and molecular mechanism models contribute broadly to plant pathogen defense.

    Science.gov (United States)

    Arya, Preeti; Acharya, Vishal

    2017-09-12

    STAND P-loop NTPase is the common weapon used by plant and other organisms from all three kingdoms of life to defend themselves against pathogen invasion. The purpose of this study is to review comprehensively the latest finding of plant STAND P-loop NTPase related to their genomic distribution, evolution, and their mechanism of action. Earlier, the plant STAND P-loop NTPase known to be comprised of only NBS-LRRs/AP-ATPase/NB-ARC ATPase. However, recent finding suggests that genome of early green plants comprised of two types of STAND P-loop NTPases: (1) mammalian NACHT NTPases and (2) NBS-LRRs. Moreover, YchF (unconventional G protein and members of P-loop NTPase) subfamily has been reported to be exceptionally involved in biotic stress (in case of Oryza sativa), thereby a novel member of STAND P-loop NTPase in green plants. The lineage-specific expansion and genome duplication events are responsible for abundance of plant STAND P-loop NTPases; where "moderate tandem and low segmental duplication" trajectory followed in majority of plant species with few exception (equal contribution of tandem and segmental duplication). Since the past decades, systematic research is being investigated into NBS-LRR function supported the direct recognition of pathogen or pathogen effectors by the latest models proposed via 'integrated decoy' or 'sensor domains' model. Here, we integrate the recently published findings together with the previous literature on the genomic distribution, evolution, and distinct models proposed for functional molecular mechanism of plant STAND P-loop NTPases.

  1. Poster contributions; Contributions par affiches

    Energy Technology Data Exchange (ETDEWEB)

    Allegraud, K.; Gatilova, I.; Guaitella, O.; Ionikh, Y.; Roepcke, J.; Rousseau, A.; Aranchuk, L.E.; Larour, J.; Asad, S.; Tendero, C.; Tixier, C.; Jaoul, C.; Tristant, P.; Boisse-Laporte, C.; Leprince, P.; Leniniven, C.; Assouar, M.B.; Jimenez Rioboo, R.J.; Aubert, X.; Rousseau, A.; Sadeghi, N.; Bekstein, A.; Benhenni, M.; Yousfi, M.; Bousquet, A.; Granier, A.; Cartry, G.; Calafat, M.; Escaich, D.; Raynaud, P.; Clergereaux, R.; Cardoso, R.P.; Belmonte, T.; Henrion, G.; Sadeghi, N.; Cavarroc, M.; Mikikian, M.; Tessier, Y.; Boufendi, I.; Celestin, S.; Guaitella, O.; Bourdon, A.; Rousseau, A.; Cernogora, G.; Szopa, C.; Cavarroc, M.; Boufendi, I.; Commaux, N.; Geraud, A.; Pegourie, B.; Clairet, F.; Gil, C.; Gros, G.; Gunn, J.; Joffrin, E.; Hertout, P.; Costin, C.; Choimet, J.B.; Minea, T.; Couedel, L.; Mikikian, M.; Tessier, Y.; Boufendi, I.; Samarian, A.A.; Cousin, R.; Larour, J.; Gouard, P.; Raymond, P.; Curley, G.A.; Booth, J.P.; Corr, C.S.; Foldes, T.; Guillon, J.; Czarny, O.; Huysmans, G.; Daniel, A.; Belmonte, T.; Poucques, L. de; Imbert, J.C.; Teule-Gay, L.; Boisse-Laporte, C.; Devaux, S.; Manfredi, G.; Dif-Pradalier, G.; Grandgirard, V.; Sarazin, Y.; Garbet, X.; Ghendrih, Ph.; Dong, B.; Bauchire, J.M.; Pouvesle, J.M.; Magnier, P.; Hong, D.; Duluard, C.; Tillocher, T.; Mekkakia Maaza, N.; Dussart, R.; Mellhaoui, X.; Lefaucheux, P.; Puech, M.; Ranson, P.; Faudot, E.; Heuraux, S.; Colas, L.; Fubiani, G.; Boilson, D.; Hemsworth, R.S.; Gatilova, L.; Allegraud, K.; Ionikh, Y.; Roepcke, J.; Cartry, G.; Rousseau, A.; Gauthier, J.C.; Fourment, C.; Schurtz, G.; Nicolai, Ph.; Peyrusse, O.; Feugeas, J.L

    2006-07-01

    This document gathers the poster contributions among which 11 are relevant for fusion plasmas or particle acceleration: 1) the spectral study of a micro plasma from an X-pinch explosion; 2) experiments with a plasma density greater than the Greenwald value via the injection of icicles in Tore-Supra; 3) Bezier's surfaces and finite elements method for non-linear MHD; 4) 2-dimensional simulation of the RF casings before the ICRF antennas in tokamaks; 5) negative ion sources for ITER; 6) experimental characterization of electron heat transport on the laser integration line; 7) comparison of fluctuation measurement methods of plasma density via reflectometry in mode-o and mode-x in Tore-Supra; 8) water-bag model applied to kinetics equations of magnetic fusion plasmas; 9) computerized simulation of electron acceleration in plasma waves generated in a capillary pipe through laser wakefield; 10) the slowing-down of an alpha particle in a strongly magnetized dense plasma; and 11) stochastic processes of particle trapping by a wave in a magnetized plasma. (A.C.)

  2. Counterion influence on the vibrational wavenumbers in ternary and quaternary metal hydride salts, A2MH6 (A = alkali metal, alkaline earth, and lanthanides; M = Ir, Fe, Ru, Os, Pt, Mn).

    Science.gov (United States)

    Gilson, Denis F R; Moyer, Ralph O

    2012-02-06

    The wavenumbers of the ν(3) metal-hydrogen stretching mode (T(1u)) in the IR spectra of both ternary and quaternary hexahydrido salts of transition metals from groups 7 to 10 ([Mn(I)H(6)](5-), [Fe(II)H(6)](4-), [Ru(II)H(6)](4-), [Os(II)H(6)](4-), [Ir(III)H(6)](3-), and [Pt(IV)H(6)](2-)) depend linearly upon the ionization energies of the counterions (alkali metal, alkaline earth, and lanthanide) with a separate line for each metal. This relationship provides quantitative support for the charge-transfer mechanism for explaining the stabilities of these compounds.

  3. Quantum mechanical calculation of energy dependence of OCl/OH product branching ratio and product quantum state distributions for the O(1D) + HCl reaction on all three contributing electronic state potential energy surfaces.

    Science.gov (United States)

    Yang, Huan; Han, Ke-Li; Nanbu, Shinkoh; Nakamura, Hiroki; Balint-Kurti, Gabriel G; Zhang, Hong; Smith, Sean C; Hankel, Marlies

    2008-08-28

    OCl/OH product branching ratios are calculated as a function of total energy for the O( (1) D) + HCl reaction using quantum wavepacket methods. The calculations take account of reaction on all the three electronic state potential energy surfaces which correlate with both reactants and products. Our results show that reaction on the excited electronic state surfaces has a large effect on the branching ratio at higher energies and that these surfaces must therefore be fully taken into account. The calculations use the potential energy surfaces of Nanbu and co-workers. Product vibrational and rotational quantum state distributions are also calculated as a function of energy for both product channels. Inclusion of the excited electronic state potential energy surfaces improves the agreement of the predicted product vibrational quantum state distributions with experiment for the OH product channel. For OCl agreement between theory and experiment is retained for the vibrational quantum state distributions when the excited electronic state potential energy surfaces are included in the analysis. For the rotational state distributions good agreement between theory and experiment is maintained for energies at which experimental results are available. At higher energies, above 0.7 eV of total energy, the OCl rotational state distributions predicted using all three electronic state potential energy surfaces shift to markedly smaller rotational quantum numbers.

  4. Unintegrated double parton distributions

    CERN Document Server

    Golec-Biernat, K

    2016-01-01

    We present the construction of unintegrated double parton distribution functions which include dependence on transverse momenta of partons. We extend the formulation which was used to obtain the single unintegrated parton distributions from the standard, integrated parton distribution functions. Starting from the homogeneous part of the evolution equations for the integrated double parton distributions, we construct the unintegrated double parton distributions as the convolutions of the integrated double distributions and the splitting functions, multiplied by the Sudakov form factors. We show that there exist three domains of external hard scales which require three distinct forms of the unintegrated double distributions. The additional transverse momentum dependence which arises through the Sudakov form factors leads to non-trivial correlations in the parton momenta. We also discuss the non-homogeneous contribution to the unintegrated double parton distributions, which arises due to the splitting of a singl...

  5. The protein kinase A pathway contributes to Hg2+-induced alterations in phosphorylation and subcellular distribution of occludin associated with increased tight junction permeability of salivary epithelial cell monolayers.

    Science.gov (United States)

    Kawedia, Jitesh D; Jiang, Mengmeng; Kulkarni, Amit; Waechter, Holly E; Matlin, Karl S; Pauletti, Giovanni M; Menon, Anil G

    2008-09-01

    Hg(2+) is commonly used as an inhibitor of many aquaporins during measurements of transcellular water transport. To investigate whether it could also act on the paracellular water transport pathway, we asked whether addition of Hg(2+) affected transport of radiolabeled probes through tight junctions of a salivary epithelial cell monolayer. Inclusion of 1 mM Hg(2+) decreased transepithelial electrical resistance by 8-fold and augmented mannitol and raffinose flux by 13-fold, which translated into an estimated 44% increase in pore radius at the tight junction. These Hg(2+)-induced effects could be partially blocked by the protein kinase A (PKA) inhibitor N-[2-((p-bromocinnamyl) amino) ethyl]-5-isoquinolinesulfonamide, 2HCl (H89), suggesting that both-PKA dependent and PKA-independent mechanisms contribute to tight junction regulation. Western blot analyses showed a 2-fold decrease in tight junction-associated occludin after Hg(2+) treatment and the presence of a novel hyperphosphorylated form of occludin in the cytoplasmic fraction. These findings were corroborated by confocal imaging. The results from this study reveal a novel contribution of the PKA pathway in Hg(2+)-induced regulation of tight junction permeability in the salivary epithelial barrier. Therapeutically, this could be explored for pharmacological intervention in the treatment of dry mouth, Sjögren's syndrome, and possibly other disorders of fluid transport.

  6. Spanish Network for Isotopes in Precipitation: Isotope Spatial distribution and contribution to the knowledge of the hydrological cycle; La Red Espanola de Vigilancia de Isotopos en la Precipitacion (REVIP): distribucion isotopica espacial y aportacion al conocimiento del ciclo hidrologico

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Teijeiro, M. F.; Rodriguez-Arevalo, J.; Castano, S.

    2009-07-01

    The results of seven years of operation of the Spanish Network for Isotopes ({sup 2}H, {sup 1}8O y {sup 3}H) in Precipitation (REVIP) are shown. this Network is managed since 2000 by the Centro de Estudios de Tecnicas Aplicadas of the Centro de Estudios y Experimentacion de Obras Publicas (CEDEX) in collaboration with the Agencia Estatal de Meteorologia (AEMET). The results of REVIP are sent to the International Atomic Energy Agency (IAEA) in order to be integrated in the Global Network for Isotopes in Precipitation (GNIP). The spatial distribution of stable isotopes ({sup 1}8O h {sup 2}H) in precipitation in Spain follows a multiple regression model, based on two geographic factors: latitude and elevation, which is strongly correlated with temperature, an important factor controlling isotope fractionation. This information on {sup 1}8O and {sup 2}H is useful to trace surface and ground waters and, combined with the information, about the spatial and temporal distribution of the Tritium ({sup 3}H) concentration in precipitation, allows to date these waters in order to estimate flow directions and velocities, and to evaluate the residence time of water resources and aquifer vulnerability. (Author)

  7. Highly Viscoelastic Worm-Like Micelle Solution of Sodium Hexadecyl Sulfate Induced by Bolaform Counterions%Bola反离子诱导的高粘弹十六烷基硫酸钠蠕虫胶束溶液

    Institute of Scientific and Technical Information of China (English)

    赵剑曦; 杨铎平

    2012-01-01

    利用稳态和频率扫描研究了十六烷基硫酸钠(SHS)与Bola盐(N,N'-双乙基二甲基-α,ω-乙烷溴化铵(Bola2Et)或N,N'-三甲基-α,ω-丁烷溴化铵(Bola4)混合体系的流变行为.实验结果表明两个体系均在45℃时形成了长蠕虫胶束,溶液呈现出高粘弹性,尤其是SHS/Bola2Et溶液表现出很高的弹性,零剪接粘度高达2520 Pa·s,表观上呈现胶状.这些结果归因于在Bola反离子诱导下,表面活性剂SHS与Bola反离子形成了静电吸引的2:1结构复合物.由于这两个Bola反离子的联接链长度均短于季铵离子的静电平衡距离,因此形成的复合物在形状上有利于蠕虫胶束生成.作为对比,添加简单的四甲基铵反离子无法诱导SHS形成蠕虫胶束,溶液仅呈现低粘度.%The rheological behaviors of mixed aqueous solutions of sodium hexadecyl sulfate (SHS) and a bolaform salt,either N,N'-ethanediyl-α,ω-bis(ethyldimethylammonium bromide) (Bola2Et) or N,N'-propanediyl-α,ω-bis(trimethylammonium bromide) (Bola4),were investigated by steady-state and frequencysweep measurements.The results showed that long worm-like micelles were formed in both systems at 45 ℃,and the solutions exhibited high viscoelasticities,especially the SHS/Bola2Et system in which the solution had very high elasticity.The zero-shear viscosity of SHS/Bola2Et was as high as 2520 Pa· s,and the system was gel-like.These results were attributed to the formation of 2:1 complexes by electrostatic attraction.Since the spacers of both Bola counterions were shorter than the distance between quaternary ammonium ions under electrostatic equilibrium,the generated complex in shape favored formation of worm-like micelles.In comparison,it was difficult to induce SHS to form worm-like micelles by the addition of tetramethylammonium counterions,and the solution exhibited low viscosity.

  8. Distribution coefficients of chlorinated hydrocarbons between muscle tissue and liver in fish. A contribution to the Federal database of environmental samples (UPB); Verteilungskoeffizienten chlorierter Kohlenwasserstoffe zwischen Muskulatur und Leber bei Fischen. Ein Beitrag zur Umweltprobenbank des Bundes (UPB)

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, K.W.; Oxynos, K.; Schmitzer, J. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Oekologische Chemie; Marth, P.; Kettrup, A. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Oekologische Chemie; Technische Univ. Muenchen, Freising (Germany). Lehrstuhl fuer Oekologische Chemie und Umweltanalytik; Wolf, A. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Klinische Kooperationsgruppe Umweltdermatologie und Allergologie; Technische Univ. Muenchen (Germany). Klinik und Poliklinik fuer Dermatologie und Allergologie am Biederstein; Hahn, K. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (DE). Inst. fuer Medizinische Informatik und Systemforschung (MEDIS)

    1999-09-01

    Measured distribution coefficients (KL{sub M/L}) related to lipid concentrations between the muscle (C{sub ML}) and liver (C{sub LL}) tissue of two fish species (Abramis brama, Zoarces viviparus) exhibit nominal values of unity according to the relationship KL{sub M/L}=C{sub ML}/C{sub LL}=1 for persistent compounds such as highly chlorinated PCB and values above one for degradable compounds for example chlorinated cyclohexanes or DDT. The corresponding theory is presented. The relationship holds for samples for single fish as well as for pooled samples. (orig.) [German] Lipidbezogene Verteilungskoeffizienten (KL{sub M/L}) zwischen Muskelkonzentrationen- (C{sub ML}) und Leberkonzentrationen (C{sub LL}) zweier Friedfischarten Brassen (Abramis brama) und Aalmutter (Zoarces viviparus) ergeben theoriekonform (KL{sub M/L}=C{sub ML}/C{sub LL}=1) nominale Werte um 1 fuer persistente (hochchlorierte PCB) und Werte ueber 1 fuer metabolisierbare lipophile Umweltchemikalien wie chlorierte Cyclohexane oder DDT. (orig.)

  9. Social Contributions in Romania

    Directory of Open Access Journals (Sweden)

    Attila Gyorgy

    2012-12-01

    Full Text Available Social contributions have an important impact on payroll policy. Also, social contributions represent a significant budgetary revenue item which can be viewed at the edge between taxation and insurance. Social contributions in Romania experienced many changes which ended in 2008. Nowadays, they are within a long transaction period towards partial externalization of the insurance activity to privately managed funds. The aim of this paper is to analyse the homogeneity of Romanian social security public scheme using annual data extracted from 2002-2009.The main findings reveal that social contributions reached the pinnacle of diversification, being too many, some of them with a small contribution rates; fiscal reforms which reduced contribution rates advantaged employers, and state will be interested to externalize this activity as far private sector will be able to assume this responsibility and the budgetary effects are acceptable for the public finance.

  10. Modelling the runoff regime of the glacierised upper Aconcagua River Basin using a distributed hydrological model: a multi-criteria approach for simulations of glacier and snow melt contributions to streamflow

    Science.gov (United States)

    Ragettli, Silvan; Pellicciotti, Francesca; Molnar, Darcy; Rimkus, Stefan; Helbing, Jakob; Escobar, Fernando; Burlando, Paolo

    2010-05-01

    In the Central Andes of Chile the interactions between snow, glaciers and water resources are governed by a distinct climatological forcing. Summers are dry and stable, with precipitation close to zero, low relative humidity and intense solar radiation. During the summer months, water originates almost exclusively from snow and ice melt. Evidence of glaciers retreat and changes in the seasonal snow cover suggests that climate change might have an impact on the water resources in the area. We use the physically-based, spatially-distributed hydrological model TOPKAPI to study the processes governing the exchange between the climate, snow and ice in the upper Aconcagua River Basin. The model incorporates the melting of snow and ice based on a simplified energy-balance approach (ETI model) and the routing of melt water through the glacial system. The model has numerous empirical parameters used in the computation of the single components of the hydrological cycle, the determination of which might lead to problems of equifinality. To address this issue we set up a rigorous calibration procedure that allows calibration of the main model parameters in three different steps by separating parameters governing distinct processes. We evaluate the parameters' transferability in time and investigate the differences in model parameters and performance that result from applying the model at different spatial scales. The model ability to simulate the relevant processes is tested against a data set of meteorological data, measurements of surface ablation and glacier runoff at the snout of the Juncal Norte Glacier during two ablation seasons. Modelled snow height is compared to snow maps derived from terrestrial photos. Results show that the magnitude of snow and icemelt rates on the glacier tongue is correctly reproduced, but simulations at higher elevation have a larger uncertainty. Crucial factors affecting model performance are the model ability to simulate the redistribution of

  11. Chemical Characteristics, Water Sources and Pathways, and Age Distribution of Ground Water in the Contributing Recharge Area of a Public-Supply Well near Tampa, Florida, 2002-05

    Science.gov (United States)

    Katz, Brian G.; Crandall, Christy A.; Metz, Patricia A.; McBride, William S.; Berndt, Marian P.

    2007-01-01

    In 2001, the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey began a series of studies on the transport of anthropogenic and natural contaminants (TANC) to public-supply wells. The main goal of the TANC program was to better understand the source, transport, and receptor factors that control contaminant movement to public-supply wells in representative aquifers of the United States. Studies were first conducted at regional scales at four of the eight TANC study areas during 2002-03 and at small (local) scales during 2003-05 in California, Nebraska, Connecticut, and Florida. In the Temple Terrace study area near Tampa, Florida, multiple chemical indicators and geochemical and ground-water flow modeling techniques were used to assess the vulnerability of a public-supply well in the karstic Upper Floridan aquifer to contamination from anthropogenic and naturally occurring contaminants. During 2003-05, water samples were collected from the public-supply well and 13 surrounding monitoring wells that all tap the Upper Floridan aquifer, and from 15 monitoring wells in the overlying surficial aquifer system and the intermediate confining unit that are located within the modeled ground-water contributing recharge area of the public-supply well. Six volatile organic compounds and four pesticides were detected in trace concentrations (well below drinking-water standards) in water from the public-supply well, which had an open interval from 36 to 53 meters below land surface. These contaminants were detected more frequently in water samples from monitoring wells in the overlying clastic surficial aquifer system than in water from monitoring wells in the Upper Floridan aquifer in the study area. Likewise, nitrate-N concentrations in the public-supply well (0.72-1.4 milligrams per liter) were more similar to median concentrations in the oxic surficial aquifer system (2.1 milligrams per liter) than to median nitrate-N concentrations in the anoxic

  12. Contributions to industrial statistics

    OpenAIRE

    2015-01-01

    This thesis is about statistics' contributions to industry. It is an article compendium comprising four articles divided in two blocks: (i) two contributions for a water supply company, and (ii) significance of the effects in Design of Experiments. In the first block, great emphasis is placed on how the research design and statistics can be applied to various real problems that a water company raises and it aims to convince water management companies that statistics can be very useful to impr...

  13. Income distribution: Second thoughts

    NARCIS (Netherlands)

    J. Tinbergen (Jan)

    1977-01-01

    textabstractAs a follow-up of his book on income distribution the author reformulates his version on the scarcity theory of income from productive contributions. The need to introduce into an earnings theory several job characteristics, non-cognitive as well as cognitive, and the corresponding perso

  14. 26 CFR 1.408A-5 - Recharacterized contributions.

    Science.gov (United States)

    2010-04-01

    ... distribution (as described in section 408(d)(3)(A)(i)), is contributed to a Roth IRA in the next taxable year... Roth IRA is worth $80,000, Taxpayer A makes a $160,000 conversion contribution to the Roth IRA. Subsequently, Taxpayer A discovers that she was ineligible to make a Roth conversion contribution in 2004...

  15. Distribution Structures

    NARCIS (Netherlands)

    Friedrich, H.; Tavasszy, L.A.; Davydenko, I.

    2013-01-01

    Distribution structures are important elements of the freight transportation system. Goods are routed via warehouses on their way from production to consumption. This chapter discusses drivers behind these structures, logistics decisions connected to distribution structures on the micro level, and

  16. Distributed Knight

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius; Damm, Christian Heide

    2005-01-01

    An extension of Knight (2005) that support distributed synchronous collaboration implemented using type-based publish/subscribe......An extension of Knight (2005) that support distributed synchronous collaboration implemented using type-based publish/subscribe...

  17. Long-ranged contributions to solvation free energies from theory and short-ranged models

    Science.gov (United States)

    Remsing, Richard C.; Liu, Shule; Weeks, John D.

    2016-03-01

    Long-standing problems associated with long-ranged electrostatic interactions have plagued theory and simulation alike. Traditional lattice sum (Ewald-like) treatments of Coulomb interactions add significant overhead to computer simulations and can produce artifacts from spurious interactions between simulation cell images. These subtle issues become particularly apparent when estimating thermodynamic quantities, such as free energies of solvation in charged and polar systems, to which long-ranged Coulomb interactions typically make a large contribution. In this paper, we develop a framework for determining very accurate solvation free energies of systems with long-ranged interactions from models that interact with purely short-ranged potentials. Our approach is generally applicable and can be combined with existing computational and theoretical techniques for estimating solvation thermodynamics. We demonstrate the utility of our approach by examining the hydration thermodynamics of hydrophobic and ionic solutes and the solvation of a large, highly charged colloid that exhibits overcharging, a complex nonlinear electrostatic phenomenon whereby counterions from the solvent effectively overscreen and locally invert the integrated charge of the solvated object.

  18. Managing Distributed Software Projects

    DEFF Research Database (Denmark)

    Persson, John Stouby

    Increasingly, software projects are becoming geographically distributed, with limited face-toface interaction between participants. These projects face particular challenges that need careful managerial attention. This PhD study reports on how we can understand and support the management of distr......Increasingly, software projects are becoming geographically distributed, with limited face-toface interaction between participants. These projects face particular challenges that need careful managerial attention. This PhD study reports on how we can understand and support the management...... of distributed software projects, based on a literature study and a case study. The main emphasis of the literature study was on how to support the management of distributed software projects, but also contributed to an understanding of these projects. The main emphasis of the case study was on how to understand...... the management of distributed software projects, but also contributed to supporting the management of these projects. The literature study integrates what we know about risks and risk-resolution techniques, into a framework for managing risks in distributed contexts. This framework was developed iteratively...

  19. Distributed computing

    CERN Document Server

    Van Renesse, R

    1991-01-01

    This series will start with an introduction to distributed computing systems. Distributed computing paradigms will be presented followed by a discussion on how several important contemporary distributed operating systems use these paradigms. Topics will include processing paradigms, storage paradigms, scalability and robustness. Throughout the course everything will be illustrated by modern distributed systems notably the Amoeba distributed operating system of the Free University in Amsterdam and the Plan 9 operating system of AT&T Bell Laboratories. Plan 9 is partly designed and implemented by Ken Thompson, the main person behind the successful UNIX operating system.

  20. Reliability evaluation of distribution systems containing renewable distributed generations

    Science.gov (United States)

    Alkuhayli, Abdulaziz Abddullah

    Reliability evaluation of distribution networks, including islanded microgrid cases, is presented. The Monte Carlo simulation algorithm is applied to a test network. The network includes three types of distributed energy resources solar photovoltaic (PV), wind turbine (WT) and gas turbine (GT). These distributed generators contribute to supply part of the load during grid-connected mode, but supply the entire load during islanded microgrid operation. PV and WT stochastic models have been used to simulate the randomness of these resources. This study shows that the implementation of distributed generations can improve the reliability of the distribution networks.

  1. Contribution to contract theory

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2016-01-01

    Full Text Available Oliver Hart and Bengt Holmstrom share the Nobel Prize in Economic Sciences for 2016, awarded to them by Sveriges Riksbank. They have been rewarded for their work in enhancing the design of contracts, i.e. arrangements connecting employers with employees or companies with clients, in other words, for their contribution to contract theory in the 1970s and 1980s. Their analysis of optimal contractual arrangements lays an intellectual foundation for designing policies and institutions in many areas, from bankruptcy legislation to political constitutions. Hart is an expert in contract theory, theory of the firm, corporate finance, and law and economics. His contribution to contract theory is exquisite when it comes to designing contracts which cover eventualities that cannot be precisely specified in advance.

  2. Molecular dynamics simulation of nanoscale distribution and mobility of water and dimethylmethylphosphonate in sulfonated polystyrene.

    Science.gov (United States)

    Vishnyakov, Aleksey; Neimark, Alexander V

    2008-11-27

    The interest in a better understanding of the specific interactions of phosphor-organic compounds and water with sulfonated polystyrene (sPS) is motivated by the use of block copolymers as protective membranes against chemical warfare agents. Using classical molecular dynamics simulations, we explored the nanoscale segregation and diffusion of water and nerve gas simulant dimethylmethylphosphonate (DMMP) in sPS neutralized with calcium counterions at different sulfonation and hydration levels. The water content was varied from 15 to 54% of dry polymer weight, and the DMMP content was varied from 0 to 100 wt %. We found that, in the 40% sulfonated polystyrene, water forms well defined aggregates, which grow in size as the hydration increases, reaching approximately 20 A at the maximum water content. In the 100% sulfonated polystyrene, the overall structure of hydrated polymer is more uniform with smaller water aggregates. Diffusion of water at the same number of water molecules per sulfonate group is faster at a lower sulfonation level. The solvation of sPS in water-DMMP binary mixtures was found to differ substantially from Nafion, where DMMP forms a layer between the hydropholic and hydrophobic subphases. In sPS with divalent Ca(2+) counterions, DMMP and water compete for the solvation of the sulfonate group. At high water and DMMP contents, the diffusion of DMMP turned out to be rather fast with a diffusion coefficient of ca. 30% of that of water. At the same time, water diffusion slows down as the DMMP concentration increases. This observation suggests that although sPS is permeable for both solvents, water and DMMP are partially segregated on the scale of 1-2 nm and have different pathways through the system. The nonuniform nanoscale distribution of water and DMMP in sPS is confirmed by analyses of different pair correlation functions. This feature may significantly affect the perm-selective properties of sPS-contained block copolymer membranes.

  3. Abstracts of contributed papers

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    This volume contains 571 abstracts of contributed papers to be presented during the Twelfth US National Congress of Applied Mechanics. Abstracts are arranged in the order in which they fall in the program -- the main sessions are listed chronologically in the Table of Contents. The Author Index is in alphabetical order and lists each paper number (matching the schedule in the Final Program) with its corresponding page number in the book.

  4. Contributions to statistics

    CERN Document Server

    Mahalanobis, P C

    1965-01-01

    Contributions to Statistics focuses on the processes, methodologies, and approaches involved in statistics. The book is presented to Professor P. C. Mahalanobis on the occasion of his 70th birthday. The selection first offers information on the recovery of ancillary information and combinatorial properties of partially balanced designs and association schemes. Discussions focus on combinatorial applications of the algebra of association matrices, sample size analogy, association matrices and the algebra of association schemes, and conceptual statistical experiments. The book then examines latt

  5. Contributions to sampling statistics

    CERN Document Server

    Conti, Pier; Ranalli, Maria

    2014-01-01

    This book contains a selection of the papers presented at the ITACOSM 2013 Conference, held in Milan in June 2013. ITACOSM is the bi-annual meeting of the Survey Sampling Group S2G of the Italian Statistical Society, intended as an international  forum of scientific discussion on the developments of theory and application of survey sampling methodologies and applications in human and natural sciences. The book gathers research papers carefully selected from both invited and contributed sessions of the conference. The whole book appears to be a relevant contribution to various key aspects of sampling methodology and techniques; it deals with some hot topics in sampling theory, such as calibration, quantile-regression and multiple frame surveys, and with innovative methodologies in important topics of both sampling theory and applications. Contributions cut across current sampling methodologies such as interval estimation for complex samples, randomized responses, bootstrap, weighting, modeling, imputati...

  6. Statistical distributions

    CERN Document Server

    Forbes, Catherine; Hastings, Nicholas; Peacock, Brian J.

    2010-01-01

    A new edition of the trusted guide on commonly used statistical distributions Fully updated to reflect the latest developments on the topic, Statistical Distributions, Fourth Edition continues to serve as an authoritative guide on the application of statistical methods to research across various disciplines. The book provides a concise presentation of popular statistical distributions along with the necessary knowledge for their successful use in data modeling and analysis. Following a basic introduction, forty popular distributions are outlined in individual chapters that are complete with re

  7. Distribution center

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Distribution center is a logistics link fulfill physical distribution as its main functionGenerally speaking, it's a large and hiahly automated center destined to receive goods from various plants and suppliers,take orders,fill them efficiently,and deliver goods to customers as quickly as possible.

  8. DEDUCTIBILITY OF CONTRIBUTIONS TO VOLUNTARY PRIVATE PENSIONS

    Directory of Open Access Journals (Sweden)

    LILIANA MUNTEAN

    2011-01-01

    Full Text Available The present paper approaches the notion of public and private pension in Romania. Pension can be seen in terms of a replacement income to individuals whose age no longer affords to operate in the labour market. Pension reform in Romania has allowed besides the public pension system, called Pillar I, which is a distributive system based on solidarity between generations also a private pension system that records the contributions of participants in individual accounts, based on capitalization, investment and accumulation of these contributions.

  9. Contributing to Functionality

    DEFF Research Database (Denmark)

    Törpel, Bettina

    2006-01-01

    advocated in this paper, emerges in the specific dynamic interplay of actors, objectives, structures, practices and means. In this view, functionality is the result of creating, harnessing and inhabiting computer supported joint action spaces. The successful creation and further development of a computer......The objective of this paper is the design of computer supported joint action spaces. It is argued against a view of functionality as residing in computer applications. In such a view the creation of functionality is equivalent to the creation of computer applications. Functionality, in the view...... supported joint action space comprises a whole range of appropriate design contributions. The approach is illustrated by the example of the creation of the computer supported joint action space "exchange network of voluntary union educators". As part of the effort a group of participants created...

  10. Contributing from the margins

    DEFF Research Database (Denmark)

    Chimirri, Niklas Alexander

    /herself as a contributor to an investigated practice, as inextricably entangled with the conducts of life of the others in relation to the conditions in practice. Doing research in the kindergarten thus becomes a mutual and collective endeavor, to which pedagogues, parents, children, and the researcher contribute. Even...... empirical study, I focused on kindergarten children’s first-person perspectives on the electronic media technologies they deemed subjectively relevant for conducting everyday life in the practice of their kindergarten. The concept of the children’s perspectives opens possibilities for transcending...... the widespread, one-sided explanations of the relationship between a child and technology, which ascribe agency either to the child or to the technology. However, attempts to access these perspectives raises a number of epistemological and ethical-political challenges, most crucially regarding the concrete role...

  11. MAIL DISTRIBUTION

    CERN Multimedia

    Mail Office

    2001-01-01

    PLEASE NOTE: changed schedule for mail distribution on 21 December 2001 afternoon delivery will be one hour earlier than usual, delivery to LHC sites will take place late morning. Thank you for your understanding.

  12. Stable distributions

    CERN Document Server

    Janson, Svante

    2011-01-01

    We give some explicit calculations for stable distributions and convergence to them, mainly based on less explicit results in Feller (1971). The main purpose is to provide ourselves with easy reference to explicit formulas. (There are no new results.)

  13. Spatial distribution

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Hendrichsen, Ditte Katrine; Nachman, Gøsta Støger

    2008-01-01

    Living organisms are distributed over the entire surface of the planet. The distribution of the individuals of each species is not random; on the contrary, they are strongly dependent on the biology and ecology of the species, and vary over different spatial scale. The structure of whole...... populations reflects the location and fragmentation pattern of the habitat types preferred by the species, and the complex dynamics of migration, colonization, and population growth taking place over the landscape. Within these, individuals are distributed among each other in regular or clumped patterns......, depending on the nature of intraspecific interactions between them: while the individuals of some species repel each other and partition the available area, others form groups of varying size, determined by the fitness of each group member. The spatial distribution pattern of individuals again strongly...

  14. Distributed Wind Market Applications

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, T.; Baring-Gould, I.

    2007-11-01

    Distributed wind energy systems provide clean, renewable power for on-site use and help relieve pressure on the power grid while providing jobs and contributing to energy security for homes, farms, schools, factories, private and public facilities, distribution utilities, and remote locations. America pioneered small wind technology in the 1920s, and it is the only renewable energy industry segment that the United States still dominates in technology, manufacturing, and world market share. The series of analyses covered by this report were conducted to assess some of the most likely ways that advanced wind turbines could be utilized apart from large, central station power systems. Each chapter represents a final report on specific market segments written by leading experts in this field. As such, this document does not speak with one voice but rather a compendium of different perspectives, which are documented from a variety of people in the U.S. distributed wind field.

  15. RNA is an integral component of chromatin that contributes to its structural organization.

    Directory of Open Access Journals (Sweden)

    Antonio Rodríguez-Campos

    Full Text Available Chromatin structure is influenced by multiples factors, such as pH, temperature, nature and concentration of counterions, post-translational modifications of histones and binding of structural non-histone proteins. RNA is also known to contribute to the regulation of chromatin structure as chromatin-induced gene silencing was shown to depend on the RNAi machinery in S. pombe, plants and Drosophila. Moreover, both in Drosophila and mammals, dosage compensation requires the contribution of specific non-coding RNAs. However, whether RNA itself plays a direct structural role in chromatin is not known. Here, we report results that indicate a general structural role for RNA in eukaryotic chromatin. RNA is found associated to purified chromatin prepared from chicken liver, or cultured Drosophila S2 cells, and treatment with RNase A alters the structural properties of chromatin. Our results indicate that chromatin-associated RNAs, which account for 2%-5% of total chromatin-associated nucleic acids, are polyA(- and show a size similar to that of the DNA contained in the corresponding chromatin fragments. Chromatin-associated RNA(s are not likely to correspond to nascent transcripts as they are also found bound to chromatin when cells are treated with alpha-amanitin. After treatment with RNase A, chromatin fragments of molecular weight >3.000 bp of DNA showed reduced sedimentation through sucrose gradients and increased sensitivity to micrococcal nuclease digestion. This structural transition, which is observed both at euchromatic and heterochromatic regions, proceeds without loss of histone H1 or any significant change in core-histone composition and integrity.

  16. Distributed optimality

    OpenAIRE

    Trommer, Jochen

    2005-01-01

    In dieser Dissertation schlage ich eine Synthese (Distributed Optimality, DO) von Optimalitätstheorie und einem derivationellen, morphologischem Asatz, Distributed Morphology (DM; Halle & Marantz, 1993) vor. Durch die Integration von OT in DM wird es möglich, Phänomene, die in DM durch sprachspezifische Regeln oder Merkmale von lexikalischen Einträge erfasst werden, auf die Interaktion von verletzbaren, universellen Constraints zurückzuführen. Andererseits leistet auch DM zwei substantielle B...

  17. Distributed Subtyping

    OpenAIRE

    Baehni, Sébastien; Barreto, Joao; Guerraoui, Rachid

    2006-01-01

    One of the most frequent operations in object-oriented programs is the "instanceof" test, also called the "subtyping" test or the "type inclusion" test. This test determines if a given object is an instance of some type. Surprisingly, despite a lot of research on distributed object-oriented languages and systems, almost no work has been devoted to the implementation of this test in a distributed environment. This paper presents the first algorithm to implement the "subtyping" test on an obje...

  18. Solute accumulation and distribution traits of an alkali resistant forage plant Kochia sieversiana and physiological contribution of organic acid under salt and alkali stresses%盐碱胁迫下抗碱牧草碱地肤溶质积累、分布特点及有机酸的生理贡献

    Institute of Scientific and Technical Information of China (English)

    麻莹; 郭立泉; 张淑芳; 王晓苹; 石德成

    2013-01-01

    对碱地肤幼苗进行盐、碱胁迫处理,通过测定各种溶质积累及分布特点,探讨碱地肤适应盐碱生境生理机制的部位差异,明确有机酸对其适应盐碱生境的贡献.结果表明,各种溶质在幼叶、成熟叶、幼茎、老茎及根等不同部位的分布存在明显差异,其中无论胁迫与否,有机酸均主要分布在茎叶之中,特别是在决定光合生产力的成熟叶片中.Na+、K+、Ca2+在不同部位的分布规律基本一致,表明Na+对K+、Ca2+的吸收与转运不存在拮抗竞争作用.实验证明了K+、Ca2+特殊的吸收机制及各溶质的分布特点对碱地肤抗盐碱生理是至关重要的;不论在盐胁迫还是碱胁迫下,有机酸在碱地肤不同部位特别是成熟叶中,均是参与渗透调节、离子平衡及pH调节的主导成分,是决定碱地肤适应盐碱生境的关键物质之一.实验同时也证明了碱地肤的不同部位对盐碱胁迫的适应机制有所不同.%The accumulation and distribution characteristics of various solutes from Kochia sieversiana seedlings stressed by salt and alkali were measured to study the physiological mechanisms in different parts of K. sieversiana and their role in adaptability to salt-alkalinized soil, and to identify the contribution of organic acid to salt-alkalinized habitat adaptability. There were considerable differences in the distribution of various solutes from different plant parts such as young leaves, mature leaves, young stems, old stems and roots. Organic acid was distributed mainly in stems and leaves, especially in mature and functional leaves on which photosynthetic productivity was dependent. Distributions of Na+ , K+ and Ca2+ in different plant parts were uniform on the whole indicating that there was no competition for Na+ , K+ and Ca2+ for absorption and transportation. Special absorption mechanisms of K+ and Ca2+ and distribution characteristics of various solutes from K. sieversiana were very important

  19. Coordination behaviour and two-dimensional-network formation in poly[[mu-aqua-diaqua(mu5-propane-1,3-diyldinitrilotetraacetato)dilithium(I)cobalt(II)] dihydrate]: the first example of an M(II)-1,3-pdta complex with a monovalent metal counter-ion.

    Science.gov (United States)

    Rychlewska, Urszula; Warzajtis, Beata; Djuran, Milos I; Radanović, Dusanka D; Dimitrijević, Mirjana Dj; Rajković, Sneaeana

    2008-06-01

    The title compound, {[CoLi2(C11H14N2O8)(H2O)3].2H2O}n, constitutes the first example of a salt of the [M(II)(1,3-pdta)](2-) complex (1,3-pdta is propane-1,3-diyldinitrilotetraacetate) with a monopositive cation as counter-ion. Insertion of the Li+ cation could only be achieved through application of the ion-exchange column technique which, however, appeared unsuccessful with other alkali metals and the ammonium cation. The structure contains two tetrahedrally coordinated Li+ cations, an octahedral [Co(1,3-pdta)](2-) anion and five water molecules, two of which are uncoordinated, and is built of two-dimensional layers extending parallel to the (010) lattice plane, the constituents of which are connected by the coordinate bonds. O-H(water)...O hydrogen bonds operate both within and between these layers. The crystal investigated belongs to the enantiomeric space group P2(1) with only one (Lambda) of two possible optical isomers of the [Co(1,3-pdta)](2-) complex. A possible cause of enantiomer separation during crystallization might be the rigidification and polarization of the [M(1,3-pdta)](2-) core, resulting from direct coordination of Li+ cations to three out of four carboxylate groups constituting the 1,3-pdta ligand. The structure of (I) differs considerably from those of the other [M(II)(1,3-pdta)](2-) complexes, in which the charge compensation is realized by means of divalent hexaaqua complex cations. This finding demonstrates a significant structure-determining role of the counter-ions.

  20. Ergonomics Contribution in Maintainability

    Science.gov (United States)

    Teymourian, Kiumars; Seneviratne, Dammika; Galar, Diego

    2017-09-01

    The objective of this paper is to describe an ergonomics contribution in maintainability. The economical designs, inputs and training helps to increase the maintainability indicators for industrial devices. This analysis can be helpful, among other cases, to compare systems, to achieve a better design regarding maintainability requirements, to improve this maintainability under specific industrial environment and to foresee maintainability problems due to eventual changes in a device operation conditions. With this purpose, this work first introduces the notion of ergonomics and human factors, maintainability and the implementation of assessment of human postures, including some important postures to perform maintenance activities. A simulation approach is used to identify the critical posture of the maintenance personnel and implements the defined postures with minimal loads on the personnel who use the equipment in a practical scenario. The simulation inputs are given to the designers to improve the workplace/equipment in order to high level of maintainability. Finally, the work concludes summarizing the more significant aspects and suggesting future research.

  1. Contribution to postnonclassical psychopathology.

    Directory of Open Access Journals (Sweden)

    Quintino-Aires J.

    2014-09-01

    Full Text Available Any psychological paradigm needs a psychopathological system that helps professionals to describe and explain the behavioral expressions that deviate from “normal” (whether this term is used with the semantic property of statistical or ideal adaptations. In this work, I seek to present the system that I have been developing since 1998 among the psychologists at the Instituto Vegotsky de Lisboa (Vygotsky Institute of Lisbon, Portugal, to understand psychopathology with regard to the vygotskian approach. It was conceived and designed according to the work of Rita Mendes Leal and her contribution to socioemotional development theory, AR Luria’s systemic and dynamic theory of the human brain, the theory of Activity (dyatel’nost of AN Leont’ev, and the psychopathological German school of E Kraepelin, presented and disseminated in Portugal in the early twentieth century by Professor Sobral Cid. It is intended to be a proposal to colleagues who are interested in postnonclassical psychology and a request for arguments.

  2. Fuel distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tison, R.R.; Baker, N.R.; Blazek, C.F.

    1979-07-01

    Distribution of fuel is considered from a supply point to the secondary conversion sites and ultimate end users. All distribution is intracity with the maximum distance between the supply point and end-use site generally considered to be 15 mi. The fuels discussed are: coal or coal-like solids, methanol, No. 2 fuel oil, No. 6 fuel oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Although the fuel state, i.e., gas, liquid, etc., can have a major impact on the distribution system, the source of these fuels (e.g., naturally-occurring or coal-derived) does not. Single-source, single-termination point and single-source, multi-termination point systems for liquid, gaseous, and solid fuel distribution are considered. Transport modes and the fuels associated with each mode are: by truck - coal, methanol, No. 2 fuel oil, and No. 6 fuel oil; and by pipeline - coal, methane, No. 2 fuel oil, No. 6 oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Data provided for each distribution system include component makeup and initial costs.

  3. Decomposition of spectral density in individual eigenvalue contributions

    Energy Technology Data Exchange (ETDEWEB)

    Bohigas, O; Pato, M P, E-mail: mpato@if.usp.b [CNRS, Universite Paris-Sud, UMR8626, LPTMS, Orsay Cedex, F-91405 (France)

    2010-09-10

    The eigenvalue densities of two random matrix ensembles, the Wigner Gaussian matrices and the Wishart covariant matrices, are decomposed in the contributions of each individual eigenvalue distribution. It is shown that the fluctuations of all eigenvalues, for medium matrix sizes, are described with a good precision by nearly normal distributions.

  4. Resummation of Transverse Momentum Distributions in Distribution Space

    CERN Document Server

    Ebert, Markus A

    2016-01-01

    Differential spectra in observables that resolve additional soft or collinear QCD emissions exhibit Sudakov double logarithms in the form of logarithmic plus distributions. Important examples are the total transverse momentum $q_T$ in color-singlet production, N-jettiness (with thrust or beam thrust as special cases), but also jet mass and more complicated jet substructure observables. The all-order logarithmic structure of such distributions is often fully encoded in differential equations, so-called (renormalization group) evolution equations. We introduce a well-defined technique of distributional scale setting, which allows one to treat logarithmic plus distributions like ordinary logarithms when solving these differential equations. In particular, this allows one (through canonical scale choices) to minimize logarithmic contributions in the boundary terms of the solution, and to obtain the full distributional logarithmic structure from the solution's evolution kernel directly in distribution space. We ap...

  5. From form factors to generalized parton distributions

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus

    2013-06-15

    I present an extraction of generalized parton distributions from selected data on the electromagnetic nucleon form factors. The extracted distributions can in particular be used to quantify the contribution to the proton spin from the total angular momentum carried by valence quarks, as well as their transverse spatial distribution inside the proton.

  6. Damage Distributions

    DEFF Research Database (Denmark)

    Lützen, Marie

    2001-01-01

    the damage location, the damage sizes and the main particulars of the struck vessel. From the numerical simulation and the analyse of the damage statistics it is found that the current formulation from the IMO SLF 43/3/2 can be used as basis for determination of the p-, r-, and v-factors. Expressions...... and methods of calculation have been discussed. The damage distributions for the different vessels have been compared and analyses regarding relations between damage parameters and main particulars have been performed. The damage statistics collected in work package 1 have been analysed for relations between...... for the distribution of the non-dimensional damage location, the non-dimensional damage length and the non-dimensional penetrations have been derived. These distributions have been used as basis for a proposal for the p- and r-factors. Two proposals for the v-factor have been performed using the damage statistics...

  7. Distributed creativity

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre

    used within the literature and yet it has the potential to revolutionise the way we think about creativity, from how we define and measure it to what we can practically do to foster and develop creativity. Drawing on cultural psychology, ecological psychology and advances in cognitive science......This book challenges the standard view that creativity comes only from within an individual by arguing that creativity also exists ‘outside’ of the mind or more precisely, that the human mind extends through the means of action into the world. The notion of ‘distributed creativity’ is not commonly......, this book offers a basic framework for the study of distributed creativity that considers three main dimensions of creative work: sociality, materiality and temporality. Starting from the premise that creativity is distributed between people, between people and objects and across time, the book reviews...

  8. EMSL Contribution Plan

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Allison A.

    2008-12-01

    This Contribution Plan is EMSL’s template for achieving our vision of simultaneous excellence in all aspects of our mission as a national scientific user facility. It reflects our understanding of the long-term stewardship we must work toward to meet the scientific challenges faced by the Department of Energy (DOE) and the nation. During the next decade, we will implement the strategies contained in this Plan, working closely with the scientific community, our advisory committees, DOE’s Office of Biological and Environmental Research, and other key stakeholders. This Plan is fully aligned with the strategic plans of DOE, its Office of Science, and the Pacific Northwest National Laboratory (PNNL). We recognize that shifts in science and technology, national priorities, and resources made available through the Federal budget process create planning uncertainties and, ultimately, a highly dynamic planning environment. Accordingly, this Plan should be viewed as a living document and we continually evaluate the changing needs and opportunities posed by our stakeholders (i.e., DOE, users, staff, advisory committees), work closely with them to understand and respond to those changes, and align our strategy accordingly. This Plan is organized around two sections. Section 1 describes our vision and four strategic outcomes: 1) Scientific Innovation, 2) Capabilities that Transform Science, 3) Outstanding Management and Operations, and Engaged and Proactive Users. These outcomes provide the framework for seven critical actions we must take during the next 3 to 5 years: 1) Establishing leadership in EMSL science themes, 2) building and deploying transformational capabilities, 3) integrating computation with experiment, 4) ensuring EMSL’s workforce meets the scientific challenges of the future, 5) creating partnerships, 6) attracting and engaging users in EMSL’s long-term strategy, and 7) building a research infrastructure that meets emerging scientific needs. Section 2

  9. Distributed Logics

    Science.gov (United States)

    2014-10-03

    that must be woven into proofs of security statements. 03-10-2014 Memorandum Report Logic System-on-a-Chip Distributed systems 9888 ASDR&EAssistant...can be removed without damaging the logic. For all propositional letters p, E1. p ⊃ [r] p From now on, a distributed logic contains at least the...a ∈ x iff 〈h〉 ∈ x. These same definitions work for the canonical relation R for r : h y k where now a ∈ MA(k), [r] a, 〈r〉 a ∈ MA(h), x ∈ CF(h), and

  10. Contributions to quantum probability

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, Tobias

    2010-06-25

    Chapter 1: On the existence of quantum representations for two dichotomic measurements. Under which conditions do outcome probabilities of measurements possess a quantum-mechanical model? This kind of problem is solved here for the case of two dichotomic von Neumann measurements which can be applied repeatedly to a quantum system with trivial dynamics. The solution uses methods from the theory of operator algebras and the theory of moment problems. The ensuing conditions reveal surprisingly simple relations between certain quantum-mechanical probabilities. It also shown that generally, none of these relations holds in general probabilistic models. This result might facilitate further experimental discrimination between quantum mechanics and other general probabilistic theories. Chapter 2: Possibilistic Physics. I try to outline a framework for fundamental physics where the concept of probability gets replaced by the concept of possibility. Whereas a probabilistic theory assigns a state-dependent probability value to each outcome of each measurement, a possibilistic theory merely assigns one of the state-dependent labels ''possible to occur'' or ''impossible to occur'' to each outcome of each measurement. It is argued that Spekkens' combinatorial toy theory of quantum mechanics is inconsistent in a probabilistic framework, but can be regarded as possibilistic. Then, I introduce the concept of possibilistic local hidden variable models and derive a class of possibilistic Bell inequalities which are violated for the possibilistic Popescu-Rohrlich boxes. The chapter ends with a philosophical discussion on possibilistic vs. probabilistic. It can be argued that, due to better falsifiability properties, a possibilistic theory has higher predictive power than a probabilistic one. Chapter 3: The quantum region for von Neumann measurements with postselection. It is determined under which conditions a probability distribution on a

  11. Distribution Principle of Bone Tissue

    CERN Document Server

    Fan, Yifang; Fan, Yubo; Xu, Zongxiang; Li, Zhiyu

    2009-01-01

    Using the analytic and experimental techniques we present an exploratory study of the mass distribution features of the high coincidence of centre of mass of heterogeneous bone tissue in vivo and its centroid of geometry position. A geometric concept of the average distribution radius of bone issue is proposed and functional relation of this geometric distribution feature between the partition density and its relative tissue average distribution radius is observed. Based upon the mass distribution feature, our results suggest a relative distance assessment index between the center of mass of cortical bone and the bone center of mass and establish a bone strength equation. Analysing the data of human foot in vivo, we notice that the mass and geometric distribution laws have expanded the connotation of Wolff's law, which implies a leap towards the quantitative description of bone strength. We finally conclude that this will not only make a positive contribution to help assess osteoporosis, but will also provide...

  12. Distributed Computing.

    Science.gov (United States)

    Ryland, Jane N.

    1988-01-01

    The microcomputer revolution, in which small and large computers have gained tremendously in capability, has created a distributed computing environment. This circumstance presents administrators with the opportunities and the dilemmas of choosing appropriate computing resources for each situation. (Author/MSE)

  13. MAIL DISTRIBUTION

    CERN Multimedia

    J. Ferguson

    2002-01-01

    Following discussions with the mail contractor and Mail Service personnel, an agreement has been reached which permits deliveries to each distribution point to be maintained, while still achieving a large proportion of the planned budget reduction in 2002. As a result, the service will revert to its previous level throughout the Laboratory as rapidly as possible. Outgoing mail will be collected from a single collection point at the end of each corridor. Further discussions are currently in progress between ST, SPL and AS divisions on the possibility of an integrated distribution service for internal mail, stores items and small parcels, which could lead to additional savings from 2003 onwards, without affecting service levels. J. Ferguson AS Division

  14. Quasihomogeneous distributions

    CERN Document Server

    von Grudzinski, O

    1991-01-01

    This is a systematic exposition of the basics of the theory of quasihomogeneous (in particular, homogeneous) functions and distributions (generalized functions). A major theme is the method of taking quasihomogeneous averages. It serves as the central tool for the study of the solvability of quasihomogeneous multiplication equations and of quasihomogeneous partial differential equations with constant coefficients. Necessary and sufficient conditions for solvability are given. Several examples are treated in detail, among them the heat and the Schrödinger equation. The final chapter is devoted to quasihomogeneous wave front sets and their application to the description of singularities of quasihomogeneous distributions, in particular to quasihomogeneous fundamental solutions of the heat and of the Schrödinger equation.

  15. Distributed Games

    OpenAIRE

    Dov Monderer; Moshe Tennenholtz

    1997-01-01

    The Internet exhibits forms of interactions which are not captured by existing models in economics, artificial intelligence and game theory. New models are needed to deal with these multi-agent interactions. In this paper we present a new model--distributed games. In such a model each players controls a number of agents which participate in asynchronous parallel multi-agent interactions (games). The agents jointly and strategically control the level of information monitoring by broadcasting m...

  16. Distributed scheduling

    OpenAIRE

    Toptal, Ayşegül

    1999-01-01

    Ankara : Department of Industrial Engineering and the Institute of Engineering and Science of Bilkent Univ., 1999. Thesis (Master's) -- Bilkent University, 1999. Includes bibliographical references. Distributed Scheduling (DS) is a new paradigm that enables the local decisionmakers make their own schedules by considering local objectives and constraints within the boundaries and the overall objective of the whole system. Local schedules from different parts of the system are...

  17. Managing Distributed Knowledge Systems

    DEFF Research Database (Denmark)

    Sørensen, Brian Vejrum; Gelbuda, Modestas

    2005-01-01

    . This paper contributes to the research on organizations as distributed knowledge systems by addressing two weaknesses of the social practice literature. Firstly, it downplays the importance of formal structure and organizational design and intervention efforts by key organizational members. Secondly, it does...... of integrating new people, building new units and adding activities to the existing organization. It is argued that knowledge is not a stable capacity that belongs to any actor alone, but that it is rather an ongoing social accomplishment, which is created and recreated as actors engage in mutual activities...

  18. Managing Distributed Knowledge Systems

    DEFF Research Database (Denmark)

    Sørensen, Brian Vejrum; Gelbuda, Modestas

    2005-01-01

    of integrating new people, building new units and adding activities to the existing organization. It is argued that knowledge is not a stable capacity that belongs to any actor alone, but that it is rather an ongoing social accomplishment, which is created and recreated as actors engage in mutual activities....... This paper contributes to the research on organizations as distributed knowledge systems by addressing two weaknesses of the social practice literature. Firstly, it downplays the importance of formal structure and organizational design and intervention efforts by key organizational members. Secondly, it does......The article argues that the growth of de novo knowledge-based organization depends on managing and coordinating increasingly growing and, therefore, distributed knowledge. Moreover, the growth in knowledge is often accompanied by an increasing organizational complexity, which is a result...

  19. ``Just Another Distribution Channel?''

    Science.gov (United States)

    Lemstra, Wolter; de Leeuw, Gerd-Jan; van de Kar, Els; Brand, Paul

    The telecommunications-centric business model of mobile operators is under attack due to technological convergence in the communication and content industries. This has resulted in a plethora of academic contributions on the design of new business models and service platform architectures. However, a discussion of the challenges that operators are facing in adopting these models is lacking. We assess these challenges by considering the mobile network as part of the value system of the content industry. We will argue that from the perspective of a content provider the mobile network is ‘just another’ distribution channel. Strategic options available for the mobile communication operators are to deliver an excellent distribution channel for content delivery or to move upwards in the value chain by becoming a content aggregator. To become a mobile content aggregator operators will have to develop or acquire complementary resources and capabilities. Whether this strategic option is sustainable remains open.

  20. Resummation of transverse momentum distributions in distribution space

    Science.gov (United States)

    Ebert, Markus A.; Tackmann, Frank J.

    2017-02-01

    Differential spectra in observables that resolve additional soft or collinear QCD emissions exhibit Sudakov double logarithms in the form of logarithmic plus distributions. Important examples are the total transverse momentum q T in color-singlet production, N -jettiness (with thrust or beam thrust as special cases), but also jet mass and more complicated jet substructure observables. The all-order logarithmic structure of such distributions is often fully encoded in differential equations, so-called (renormalization group) evolution equations. We introduce a well-defined technique of distributional scale setting, which allows one to treat logarithmic plus distributions like ordinary logarithms when solving these differential equations. In particular, this allows one (through canonical scale choices) to minimize logarithmic contributions in the boundary terms of the solution, and to obtain the full distributional logarithmic structure from the solution's evolution kernel directly in distribution space. We apply this technique to the q T distribution, where the two-dimensional nature of convolutions leads to additional difficulties (compared to one-dimensional cases like thrust), and for which the resummation in distribution (or momentum) space has been a long-standing open question. For the first time, we show how to perform the RG evolution fully in momentum space, thereby directly resumming the logarithms [ln n ( q T 2 / Q 2)/ q T 2 ]+ appearing in the physical q T distribution. The resummation accuracy is then solely determined by the perturbative expansion of the associated anomalous dimensions.

  1. Distribution switchgear

    CERN Document Server

    Stewart, Stan

    2004-01-01

    Switchgear plays a fundamental role within the power supply industry. It is required to isolate faulty equipment, divide large networks into sections for repair purposes, reconfigure networks in order to restore power supplies and control other equipment.This book begins with the general principles of the Switchgear function and leads on to discuss topics such as interruption techniques, fault level calculations, switching transients and electrical insulation; making this an invaluable reference source. Solutions to practical problems associated with Distribution Switchgear are also included.

  2. Mail distribution

    CERN Multimedia

    2007-01-01

    Please note that starting from 1 March 2007, the mail distribution and collection times will be modified for the following buildings: 6, 8, 9, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 29, 69, 40, 70, 101, 102, 109, 118, 152, 153, 154, 155, 166, 167, 169, 171, 174, 261, 354, 358, 576, 579 and 580. Complementary Information on the new times will be posted on the entry doors and left in the mail boxes of each building. TS/FM Group

  3. Dose distributions around selectron applicators

    Energy Technology Data Exchange (ETDEWEB)

    Pla, C.; Evans, M.D.; Podgorsak, E.B.

    1987-11-01

    Measured and calculated dose distributions around selectron applicators, loaded with /sup 60/Co high dose rate pellets, are presented. The effect of the stopping screw, spacers, pellets themselves and the applicator wall on the dose distribution is discussed. The measured dose distribution is in almost perfect agreement with the calculated distribution in planes perpendicular to the applicator axis and containing a source. On the applicator axis directly below the applicator the measured dose amounts to about 75% of the calculated value, when only the stopping screw attenuates the beam from a pellet. When the beam is attenuated by spacers in addition to the stopping screw, the discrepancy between the calculated and measured dose may exceed 50%. Clinically relevant source geometries are also discussed. It is shown that for most regions around the applicator the method of a simple addition of dose contributions from individual point sources is an acceptable approximation for the calculation of dose distributions around the selectron applicators.

  4. 75 FR 43799 - Employee Contribution Elections and Contribution Allocations

    Science.gov (United States)

    2010-07-27

    ... Part 1600 Employee Contribution Elections and Contribution Allocations AGENCY: Federal Retirement...), which was established by the Federal Employees' Retirement System Act of 1986 (FERSA), Public Law 99-335...-79. The TSP is a tax-deferred retirement savings plan for Federal civilian employees and members...

  5. 75 FR 32659 - Contributed Property

    Science.gov (United States)

    2010-06-09

    ... Internal Revenue Service 26 CFR Part 1 RIN 1545-BF28 Contributed Property AGENCY: Internal Revenue Service... property to the partnership. In that regard, the anti- abuse rule of Sec. 1.701-2(b) provides that, if a... contribution of property to a partnership should be recast to avoid results that are inconsistent...

  6. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  7. Optimal residential smart appliances scheduling considering distribution network constraints

    National Research Council Canada - National Science Library

    Kim, Yu-Ree; Kim, Min-Jeong; Park, Yong-Gi; Roh, Jae-Hyung; Park, Jong-Bae; Son, Sung-Yong

    2016-01-01

    As smart appliances (SAs) are more widely adopted within distribution networks, residential consumers can contribute to electricity market operations with demand response resources and reduce their electricity bill...

  8. Distributed Collaborative Learning Communities Enabled by Information Communication Technology

    NARCIS (Netherlands)

    H.L. Alvarez (Heidi Lee)

    2006-01-01

    textabstractHow and why can Information Communication Technology (ICT) contribute to enhancing learning in distributed Collaborative Learning Communities (CLCs)? Drawing from relevant theories concerned with phenomenon of ICT enabled distributed collaborative learning, this book identifies gaps in

  9. Introducing and modeling inefficiency contributions

    DEFF Research Database (Denmark)

    Asmild, Mette; Kronborg, Dorte; Matthews, Kent

    2016-01-01

    Whilst Data Envelopment Analysis (DEA) is the most commonly used non-parametric benchmarking approach, the interpretation and application of DEA results can be limited by the fact that radial improvement potentials are identified across variables. In contrast, Multi-directional Efficiency Analysis......-called inefficiency contributions, which are defined as the relative contributions from specific variables to the overall levels of inefficiencies. A statistical model for distinguishing the inefficiency contributions between subgroups is proposed and the method is illustrated on a data set on Chinese banks....

  10. ECN contributions to GLOBAL `95

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    This report contains the 9 contributions of the Netherlands Energy Research Foundation ECN to the international conference on evaluation of emerging nuclear fuel cycle systems, GLOBAL `95, held in Versailles, France, on September 11-14, 1995. (orig./GL).

  11. Uncapacitated facility location problems: contributions

    Directory of Open Access Journals (Sweden)

    Galvão Roberto Diéguez

    2004-01-01

    Full Text Available The objective of the present paper is to review my personal contributions in the field of uncapacitated facility location problems. These contributions took place throughout my academic career, from the time I was a Ph.D. student at Imperial College to the present day. They cover approximately 30 years, from 1973 to 2003; they address: algorithms developed for the p-median problem and for a general formulation of uncapacitated location problems; the study of dynamic location models; covering and hierarchical location problems; queuing-based probabilistic location models. The contributions encompass theoretical developments, computational algorithms and practical applications. All work took place in an academic environment, with the invaluable collaboration of colleagues (both in Brazil and abroad and research students at COPPE. Each section in the paper is dedicated to a topic that involves a personal contribution. Every one of them is placed within the context of the existing literature.

  12. Aid Distribution and Cooperation in Unequal Communities

    NARCIS (Netherlands)

    Exelle, D' B.; Berg, van den M.M.

    2014-01-01

    We experimentally study aid distribution and cooperation in a field lab in rural Nicaragua. In the first stage of the experimental game, participants contribute to a collective effort that determines the amount of aid given to the group, which is distributed among the players in a second stage. We f

  13. A distributed Kalman filter with global covariance

    NARCIS (Netherlands)

    Sijs, J.; Lazar, M.

    2011-01-01

    Most distributed Kalman filtering (DKF) algorithms for sensor networks calculate a local estimate of the global state-vector in each node. An important challenge within distributed estimation is that all sensors in the network contribute to the local estimate in each node. In this paper, a novel DKF

  14. Compressed sensing for distributed systems

    CERN Document Server

    Coluccia, Giulio; Magli, Enrico

    2015-01-01

    This book presents a survey of the state-of-the art in the exciting and timely topic of compressed sensing for distributed systems. It has to be noted that, while compressed sensing has been studied for some time now, its distributed applications are relatively new. Remarkably, such applications are ideally suited to exploit all the benefits that compressed sensing can provide. The objective of this book is to provide the reader with a comprehensive survey of this topic, from the basic concepts to different classes of centralized and distributed reconstruction algorithms, as well as a comparison of these techniques. This book collects different contributions on these aspects. It presents the underlying theory in a complete and unified way for the first time, presenting various signal models and their use cases. It contains a theoretical part collecting latest results in rate-distortion analysis of distributed compressed sensing, as well as practical implementations of algorithms obtaining performance close to...

  15. Stuart Hall’ Contributions to CCCS

    Institute of Scientific and Technical Information of China (English)

    涂艳

    2014-01-01

    Hall is the most prominent master of Birmingham school. To some extent, Hall just represents CCCS and makes outstanding contributions to establishment of this school. Hall’s cultural theory is characterized by the interdisciplinary ideology, cultural gaze of race diaspora, collective creation, academic openness, cultural politics, civilization of the talent and so on, so that displays his value and significance as a cultural theorists and critic, in addition demonstrates his contribution to the whole world.

  16. Patterns of drug distribution: implications and issues.

    Science.gov (United States)

    Johnson, Bruce D

    2003-01-01

    This article delineates various patterns of illicit sales of drugs, especially at the retail (and near-retail) level, addressing a variety of central issues about drug sales and distribution documented during the past 30 years. including: a) the links between drug consumption and drug distribution activities; b) the various distribution roles; c) various levels of the distribution hierarchy; d) types of retail and wholesale markets; e) the association of drug distribution with nondrug associated criminality and violence. The article also will address the implications of drug distribution: whether various public policies such as supply reduction and source interdiction affect illicit drug markets, and how policing strategies and various law enforcement strategies can influence the involvement of individual participation in drug distribution activities. The overlooked contribution of treatment for "drug abuse" to reducing drug sales and distribution activities also will be considered as will other critical unresolved issues.

  17. Full-Quantum chemical calculation of the absorption maximum of bacteriorhodopsin: a comprehensive analysis of the amino acid residues contributing to the opsin shift

    Science.gov (United States)

    Hayashi, Tomohiko; Matsuura, Azuma; Sato, Hiroyuki; Sakurai, Minoru

    2012-01-01

    Herein, the absorption maximum of bacteriorhodopsin (bR) is calculated using our recently developed method in which the whole protein can be treated quantum mechanically at the level of INDO/S-CIS//ONIOM (B3LYP/6-31G(d,p): AMBER). The full quantum mechanical calculation is shown to reproduce the so-called opsin shift of bR with an error of less than 0.04 eV. We also apply the same calculation for 226 different bR mutants, each of which was constructed by replacing any one of the amino acid residues of the wild-type bR with Gly. This substitution makes it possible to elucidate the extent to which each amino acid contributes to the opsin shift and to estimate the inter-residue synergistic effect. It was found that one of the most important contributions to the opsin shift is the electron transfer from Tyr185 to the chromophore upon excitation. We also indicate that some aromatic (Trp86, Trp182) and polar (Ser141, Thr142) residues, located in the vicinity of the retinal polyene chain and the β-ionone ring, respectively, play an important role in compensating for the large blue-shift induced by both the counterion residues (Asp85, Asp212) and an internal water molecule (W402) located near the Schiff base linkage. In particular, the effect of Trp86 is comparable to that of Tyr185. In addition, Ser141 and Thr142 were found to contribute to an increase in the dipole moment of bR in the excited state. Finally, we provide a complete energy diagram for the opsin shift together with the contribution of the chromophore-protein steric interaction. PMID:27493528

  18. 75 FR 34388 - Employee Contribution Elections and Contribution Allocations

    Science.gov (United States)

    2010-06-17

    ...; ] FEDERAL RETIREMENT THRIFT INVESTMENT BOARD 5 CFR Part 1600 Employee Contribution Elections and... Employees' Retirement System Act of 1986 (FERSA), Public Law 99-335, 100 Stat. 514. The TSP provisions of... retirement savings plan for Federal civilian employees and members of the uniformed services. The TSP...

  19. Stuart Hall’ Contributions to CCCS

    Institute of Scientific and Technical Information of China (English)

    涂艳

    2014-01-01

    Hall is the most prominent master of Birmingham school.To some extent,Hall just represents CCCS and makes outstanding contributions to establishment of this school.Hall’s cultural theory is characterized by the interdisciplinary ideology,cultural gaze of race diaspora,collective creation,academic openness,cultural politics,civilization of the talent and so on,so that displays his value and significance as a cultural theorists and critic,in addition demonstrates his contribution to the whole world.

  20. Rainfall seasonality and pest pressure as determinants of tropical tree species' distributions

    OpenAIRE

    2012-01-01

    Drought and pests are primary abiotic and biotic factors proposed as selective filters acting on species distributions along rainfall gradients in tropical forests and may contribute importantly to species distributional limits, performance, and diversity gradients. Recent research demonstrates linkages between species distributions along rainfall gradients and physiological drought tolerance; corresponding experimental examinations of the contribution of pest pressure to distributional limit...

  1. The Folded t Distribution

    OpenAIRE

    Psarakis, Stelios; Panaretos, John

    1990-01-01

    Measurements are frequently recorder without their algebraic sign. As a consequence the underlying distribution of measurements is replaced by a distribution of absolute measurements. When the underlying distribution is t the resulting distribution is called the “folded-t distribution”. Here we study this distribution, we find the relationship between the folded-t distribution and a special case of the folded normal distribution and we derive relationships of the folded-t distribution to othe...

  2. Fundamental plane: dark matter and dissipation contributions

    CERN Document Server

    Ribeiro, Andre L B

    2010-01-01

    Stellar and galactic systems are objects in dynamical equilibrium that are composed of ordinary baryonic matter hypothetically embedded in extended dominant dark matter halos. Our aim is to investigate the scaling relations and dissipational features of these objects over a wide range of their properties, taking the dynamical influence of the dark matter component into account. We study the physical properties of these self-gravitating systems using the two-component virial theorem in conjunction with data that embrace a wide range of astrophysical systems. We find that the scaling relations defined by the properties of these objects admit a dark-to-luminous density ratio parameter as a natural requirement in this framework. We also probe dissipational effects on the fundamental surface defined by the two-component virial theorem and discuss their relations with respect to the region devoid of objects in the data distribution. Our results indicate complementary contributions of dissipation and dark matter to ...

  3. Gravitational contribution to fermion masses

    CERN Document Server

    Tiemblo, A; Tiemblo, Alfredo; Tresguerres, Romualdo

    2005-01-01

    In the context of a nonlinear gauge theory of the Poincar\\'e group, we show that covariant derivatives of Dirac fields include a coupling to the translational connections, manifesting itself in the matter action as a universal background mass contribution to fermions.

  4. Assessing Contributions to Group Assignments

    Science.gov (United States)

    Johnston, Lucy; Miles, Lynden

    2004-01-01

    We report the use of a combination of self- and peer-assessment in an undergraduate social psychology laboratory course. Students worked in small groups on a self-directed empirical project that they each wrote up independently as a laboratory report. Marks for the written assignment were moderated by a contribution index measure based on the…

  5. Gravitational contribution to fermion masses

    OpenAIRE

    Tiemblo, Alfredo; Tresguerres, Romualdo

    2005-01-01

    In the context of a nonlinear gauge theory of the Poincar\\'e group, we show that covariant derivatives of Dirac fields include a coupling to the translational connections, manifesting itself in the matter action as a universal background mass contribution to fermions.

  6. Gravitational contribution to fermion masses

    Energy Technology Data Exchange (ETDEWEB)

    Tiemblo, A.; Tresguerres, R. [Consejo Superior de Investigaciones Cientificas, Instituto de Matematicas y Fisica Fundamental, Madrid (Spain)

    2005-08-01

    In the context of a non-linear gauge theory of the Poincare group, we show that covariant derivatives of Dirac fields include a coupling to the translational connections, manifesting itself in the matter action as a universal background mass contribution to fermions. (orig.)

  7. Processed foods: contributions to nutrition.

    Science.gov (United States)

    Weaver, Connie M; Dwyer, Johanna; Fulgoni, Victor L; King, Janet C; Leveille, Gilbert A; MacDonald, Ruth S; Ordovas, Jose; Schnakenberg, David

    2014-06-01

    Both fresh and processed foods make up vital parts of the food supply. Processed food contributes to both food security (ensuring that sufficient food is available) and nutrition security (ensuring that food quality meets human nutrient needs). This ASN scientific statement focuses on one aspect of processed foods: their nutritional impacts. Specifically, this scientific statement 1) provides an introduction to how processed foods contribute to the health of populations, 2) analyzes the contribution of processed foods to "nutrients to encourage" and "constituents to limit" in the American diet as recommended by the Dietary Guidelines for Americans, 3) identifies the responsibilities of various stakeholders in improving the American diet, and 4) reviews emerging technologies and the research needed for a better understanding of the role of processed foods in a healthy diet. Analyses of the NHANES 2003-2008 show that processed foods provide both nutrients to encourage and constituents to limit as specified in the 2010 Dietary Guidelines for Americans. Of the nutrients to encourage, processed foods contributed 55% of dietary fiber, 48% of calcium, 43% of potassium, 34% of vitamin D, 64% of iron, 65% of folate, and 46% of vitamin B-12. Of the constituents to limit, processed foods contributed 57% of energy, 52% of saturated fat, 75% of added sugars, and 57% of sodium. Diets are more likely to meet food guidance recommendations if nutrient-dense foods, either processed or not, are selected. Nutrition and food science professionals, the food industry, and other stakeholders can help to improve the diets of Americans by providing a nutritious food supply that is safe, enjoyable, affordable, and sustainable by communicating effectively and accurately with each other and by working together to improve the overall knowledge of consumers.

  8. 10th International Symposium on Intelligent Distributed Computing

    CERN Document Server

    Seghrouchni, Amal; Beynier, Aurélie; Camacho, David; Herpson, Cédric; Hindriks, Koen; Novais, Paulo

    2017-01-01

    This book presents the combined peer-reviewed proceedings of the tenth International Symposium on Intelligent Distributed Computing (IDC’2016), which was held in Paris, France from October 10th to 12th, 2016. The 23 contributions address a range of topics related to theory and application of intelligent distributed computing, including: Intelligent Distributed Agent-Based Systems, Ambient Intelligence and Social Networks, Computational Sustainability, Intelligent Distributed Knowledge Representation and Processing, Smart Networks, Networked Intelligence and Intelligent Distributed Applications, amongst others.

  9. Modeled ground water age distributions

    Science.gov (United States)

    Woolfenden, Linda R.; Ginn, Timothy R.

    2009-01-01

    The age of ground water in any given sample is a distributed quantity representing distributed provenance (in space and time) of the water. Conventional analysis of tracers such as unstable isotopes or anthropogenic chemical species gives discrete or binary measures of the presence of water of a given age. Modeled ground water age distributions provide a continuous measure of contributions from different recharge sources to aquifers. A numerical solution of the ground water age equation of Ginn (1999) was tested both on a hypothetical simplified one-dimensional flow system and under real world conditions. Results from these simulations yield the first continuous distributions of ground water age using this model. Complete age distributions as a function of one and two space dimensions were obtained from both numerical experiments. Simulations in the test problem produced mean ages that were consistent with the expected value at the end of the model domain for all dispersivity values tested, although the mean ages for the two highest dispersivity values deviated slightly from the expected value. Mean ages in the dispersionless case also were consistent with the expected mean ages throughout the physical model domain. Simulations under real world conditions for three dispersivity values resulted in decreasing mean age with increasing dispersivity. This likely is a consequence of an edge effect. However, simulations for all three dispersivity values tested were mass balanced and stable demonstrating that the solution of the ground water age equation can provide estimates of water mass density distributions over age under real world conditions.

  10. Product Distributions for Distributed Optimization. Chapter 1

    Science.gov (United States)

    Bieniawski, Stefan R.; Wolpert, David H.

    2004-01-01

    With connections to bounded rational game theory, information theory and statistical mechanics, Product Distribution (PD) theory provides a new framework for performing distributed optimization. Furthermore, PD theory extends and formalizes Collective Intelligence, thus connecting distributed optimization to distributed Reinforcement Learning (FU). This paper provides an overview of PD theory and details an algorithm for performing optimization derived from it. The approach is demonstrated on two unconstrained optimization problems, one with discrete variables and one with continuous variables. To highlight the connections between PD theory and distributed FU, the results are compared with those obtained using distributed reinforcement learning inspired optimization approaches. The inter-relationship of the techniques is discussed.

  11. Studies of the B-Z transition of DNA: The temperature dependence of the free-energy difference, the composition of the counterion sheath in mixed salt, and the preparation of a sample of the 5'-d[T-(m(5) C-G)12 -T] duplex in pure B-DNA or Z-DNA form.

    Science.gov (United States)

    Guéron, Maurice; Plateau, Pierre; Filoche, Marcel

    2016-07-01

    It is often envisioned that cations might coordinate at specific sites of nucleic acids and play an important structural role, for instance in the transition between B-DNA and Z-DNA. However, nucleic acid models explicitly devoid of specific sites may also exhibit features previously considered as evidence for specific binding. Such is the case of the "composite cylinder" (or CC) model which spreads out localized features of DNA structure and charge by cylindrical averaging, while sustaining the main difference between the B and Z structures, namely the better immersion of the B-DNA phosphodiester charges in the solution. Here, we analyze the non-electrostatic component of the free-energy difference between B-DNA and Z-DNA. We also compute the composition of the counterion sheath in a wide range of mixed-salt solutions and of temperatures: in contrast with the large difference of composition between the B-DNA and Z-DNA forms, the temperature dependence of sheath composition, previously unknown, is very weak. In order to validate the model, the mixed-salt predictions should be compared to experiment. We design a procedure for future measurements of the sheath composition based on Anomalous Small-Angle X-ray Scattering and complemented by (31) P NMR. With due consideration for the kinetics of the B-Z transition and for the capacity of generating at will the B or Z form in a single sample, the 5'-d[T-(m(5) C-G)12 -T] 26-mer emerges as a most suitable oligonucleotide for this study. Finally, the application of the finite element method to the resolution of the Poisson-Boltzmann equation is described in detail. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 369-384, 2016.

  12. [N(CH3)4]2[Mn(H2O)]3[Mo(CN)7](2).2H2O: a new high Tc cyano-bridged ferrimagnet based on the [MoIII(CN)7]4- building block and induced by counterion exchange.

    Science.gov (United States)

    Larionova, Joulia; Clérac, Rodolphe; Donnadieu, Bruno; Guérin, Christian

    2002-06-17

    The title compound was synthesized by slow diffusion of aqueous solutions containing K4[Mo(CN)7].2H2O, [Mn(H2O)6](NO3)2, and [N(CH3)4]Cl. The compound crystallized in monoclinic space group C2/c, a = 25.8546(14), b = 12.3906(7), c = 13.5382(7) A, beta = 116.4170 (10) degrees, Z = 4, R = 0.0353, wR2 = 0.0456. The MoIII site is surrounded by six -C-N-Mn linkages and one terminal cyano group in a distorted capped-prism fashion. There are two pentahedral MnII sites in the structure, both with four -N-C-Mo linkages and one water molecule. The anisotropic three-dimensional structure consists of connected corrugated gridlike sheet layers parallel to the bc plane. Tetramethylammonium counterions ([N(CH3)4]+) located between these layers seem to induce their distortion. The three-dimensional organization may also be viewed as interconnected octagonal channels propagated along the c axis. The void space of these channels is occupied by coordinated and crystalized water molecules. Temperature and field dependence of the magnetization in both the dc and ac modes have been measured on polycrystalline sample. These investigations have revealed that the compound ordered ferrimagnetically at Tc = 86 K, with a small hysteresis effect. These findings have been compared to those reported previously for three- and two-dimensional materials of the same family.

  13. Renormalon's Contribution to Effective Couplings

    CERN Document Server

    Suzuki, H

    1998-01-01

    When an asymptotically non-free theory possesses a mass scale, the ultraviolet (UV) renormalon gives rise to non-perturbative contributions to dimension-four operators and dimensionless couplings, thus has a similar effect as the instanton. We illustrate this phenomenon in O(N) symmetric massive briefly compared with non-perturbative corrections in the magnetic picture of the Seiberg-Witten theory.

  14. Mead's contributions to learner's identities

    OpenAIRE

    Gatt, Suzanne; Puigdellívol, Ignasi; Molina Roldán, Silvia

    2010-01-01

    Mead’s approach of symbolic interactionism is useful for explaining both how students learn and how learning environments can be improved. This article reviews Mead’s theoretical contributions, which serve as a base for successful educational actions in several countries. The interactionist view of learning is examined in depth, as well as the dialogical nature of the self, and the way that verbal language and gestures mediate interaction. These concepts are illustrated with examples from cas...

  15. Feller's Contributions to Mathematical Biology

    OpenAIRE

    Baake, Ellen; Wakolbinger, Anton

    2015-01-01

    This is a review of William Feller's important contributions to mathematical biology. The seminal paper [Feller1951] "Diffusion processes in genetics" was particularly influential on the development of stochastic processes at the interface to evolutionary biology, and interesting ideas in this direction (including a first characterization of what is nowadays known as "Feller's branching diffusion") already shaped up in the paper [Feller 1939] (written in German) "The foundations of a probabis...

  16. Changes in accounting for contributions.

    Science.gov (United States)

    Pelfrey, S

    1992-03-01

    A proposed accounting change in the timing of income recognition for restricted contributions and pledges can greatly impact a hospital's excess of revenue over expenses (net income). The author addresses steps that administrators can take to lessen its impact. With this knowledge, nurse administrators and other hospital executives can plan alternatives to reduce the income recognition and prepare themselves to answer questions posed by patients and members of the community regarding increased hospital profits.

  17. Methanotrophs Contribute to Peatland Nitrogen

    Science.gov (United States)

    Larmola, Tuula; Leppänen, Sanna M.; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

    2016-04-01

    Atmospheric nitrogen (N2) fixation is potentially an important N input mechanism to peatland ecosystems, but the extent of this process may have been underestimated because of the methods traditionally used inhibit the activity of methanothrophs. We examined the linkage of methane (CH4) oxidation and N2 fixation using 15N2 technique. Dominant flark and hummock Sphagnum species were collected from twelve pristine peatlands in Siikajoki, Finland, which varied in age from 200 to 2,500 y due to the postglacial rebound. The mosses were incubated in a two-day field 15N2 and 13CH4 pulse labelling experiment and the incorporation of 15N2 and 13CH4 in biomass was measured with Isotope Ratio Mass Spectrometer. The rates of Sphagnum-associated N2 fixation (0.1-2.9 g N m-2 y-1) were up to 10 times the current N deposition rates. Methane-induced N2 fixation contributed to over 1/3 of moss-associated N2 fixation in younger stages, but was switched off in old successional stages, despite active CH4 oxidation in these stages. Both the N2 fixation rates and the methanotrophic contribution to N2 fixation during peatland succession were primarily constrained by phosphorus availability. Previously overlooked methanotrophic N contribution may explain rapid peat and N accumulation during fen stages of peatland development. Reference. Larmola T., Leppänen S.M., Tuittila E.-S, Aarva M., Merilä P., Fritze H., Tiirola M. (2014) Methanotrophy induces nitrogen fixation during peatland development. Proceedings of the National Academy of Sciences USA 111 (2): 734-739.

  18. Ethnographic Contributions to Method Development

    DEFF Research Database (Denmark)

    Leander, Anna

    2016-01-01

    of IR—Critical Security Studies. Ethnographic research works with what has been termed a “strong” understanding of objectivity. When this understanding is taken seriously, it must lead to a refashioning of the processes of gathering, analyzing, and presenting data in ways that reverse many standard......Contrary to common assumptions, there is much to be learned about methods from constructivist/post-structuralist approaches to International Relations (IR) broadly speaking. This article develops this point by unpacking the contributions of one specific method—ethnography—as used in one subfield...

  19. IVS contribution to ITRF2014

    Science.gov (United States)

    Bachmann, Sabine; Thaller, Daniela; Roggenbuck, Ole; Lösler, Michael; Messerschmitt, Linda

    2016-07-01

    Every few years the International Terrestrial Reference System (ITRS) Center of the International Earth Rotation and Reference Systems Service (IERS) decides to generate a new version of the International Terrestrial Reference Frame (ITRF). For the upcoming ITRF2014 the official contribution of the International VLBI Service for Geodesy and Astrometry (IVS) comprises 5796 combined sessions in SINEX file format from 1979.6 to 2015.0 containing 158 stations, overall. Nine AC contributions were included in the combination process, using five different software packages. Station coordinate time series of the combined solution show an overall repeatability of 3.3 mm for the north, 4.3 mm for the east and 7.5 mm for the height component over all stations. The minimum repeatabilities are 1.5 mm for north, 2.1 mm for east and 2.9 mm for height. One of the important differences between the IVS contribution to the ITRF2014 and the routine IVS combination is the omission of the correction for non-tidal atmospheric pressure loading (NTAL). Comparisons between the amplitudes of the annual signals derived by the VLBI observations and the annual signals from an NTAL model show that for some stations, NTAL has a high impact on station height variation. For other stations, the effect of NTAL is low. Occasionally other loading effects have a higher influence (e.g. continental water storage loading). External comparisons of the scale parameter between the VTRF2014 (a TRF based on combined VLBI solutions), DTRF2008 (DGFI-TUM realization of ITRS) and ITRF2008 revealed a significant difference in the scale. A scale difference of 0.11 ppb (i.e. 0.7 mm on the Earth's surface) has been detected between the VTRF2014 and the DTRF2008, and a scale difference of 0.44 ppb (i.e. 2.8 mm on the Earth's surface) between the VTRF2014 and ITRF2008. Internal comparisons between the EOP of the combined solution and the individual solutions from the AC contributions show a WRMS in X- and Y-Pole between

  20. Probability distribution relationships

    Directory of Open Access Journals (Sweden)

    Yousry Abdelkader

    2013-05-01

    Full Text Available In this paper, we are interesting to show the most famous distributions and their relations to the other distributions in collected diagrams. Four diagrams are sketched as networks. The first one is concerned to the continuous distributions and their relations. The second one presents the discrete distributions. The third diagram is depicted the famous limiting distributions. Finally, the Balakrishnan skew-normal density and its relationship with the other distributions are shown in the fourth diagram.

  1. Distributed Computing: An Overview

    OpenAIRE

    Md. Firoj Ali; Rafiqul Zaman Khan

    2015-01-01

    Decrease in hardware costs and advances in computer networking technologies have led to increased interest in the use of large-scale parallel and distributed computing systems. Distributed computing systems offer the potential for improved performance and resource sharing. In this paper we have made an overview on distributed computing. In this paper we studied the difference between parallel and distributed computing, terminologies used in distributed computing, task allocation in distribute...

  2. Nobel Prizes: Contributions to Cardiology

    Directory of Open Access Journals (Sweden)

    Evandro Tinoco Mesquita

    2015-01-01

    Full Text Available The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize’s history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15% studies were important for cardiovascular area. There were 33 (16% laureates, and two (6% were women. Fourteen (42% were American, 15 (45% Europeans and four (13% were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male.

  3. Nobel prizes: contributions to cardiology.

    Science.gov (United States)

    Mesquita, Evandro Tinoco; Marchese, Luana de Decco; Dias, Danielle Warol; Barbeito, Andressa Brasil; Gomes, Jonathan Costa; Muradas, Maria Clara Soares; Lanzieri, Pedro Gemal; Gismondi, Ronaldo Altenburg

    2015-08-01

    The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize's history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15%) studies were important for cardiovascular area. There were 33 (16%) laureates, and two (6%) were women. Fourteen (42%) were American, 15 (45%) Europeans and four (13%) were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male.

  4. Nobel Prizes: Contributions to Cardiology

    Directory of Open Access Journals (Sweden)

    Evandro Tinoco Mesquita

    2015-08-01

    Full Text Available The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize’s history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15% studies were important for cardiovascular area. There were 33 (16% laureates, and two (6% were women. Fourteen (42% were American, 15 (45% Europeans and four (13% were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male.

  5. Nobel Prizes: Contributions to Cardiology

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Evandro Tinoco; Marchese, Luana de Decco; Dias, Danielle Warol; Barbeito, Andressa Brasil; Gomes, Jonathan Costa; Muradas, Maria Clara Soares; Lanzieri, Pedro Gemal; Gismondi, Ronaldo Altenburg, E-mail: ronaldo@floralia.com.br [Universidade Federal Fluminense, Niterói, RJ (Brazil)

    2015-08-15

    The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize’s history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15%) studies were important for cardiovascular area. There were 33 (16%) laureates, and two (6%) were women. Fourteen (42%) were American, 15 (45%) Europeans and four (13%) were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male.

  6. Nobel Prizes: Contributions to Cardiology

    Science.gov (United States)

    Mesquita, Evandro Tinoco; Marchese, Luana de Decco; Dias, Danielle Warol; Barbeito, Andressa Brasil; Gomes, Jonathan Costa; Muradas, Maria Clara Soares; Lanzieri, Pedro Gemal; Gismondi, Ronaldo Altenburg

    2015-01-01

    The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize’s history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15%) studies were important for cardiovascular area. There were 33 (16%) laureates, and two (6%) were women. Fourteen (42%) were American, 15 (45%) Europeans and four (13%) were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male. PMID:25945466

  7. Distributed user interfaces usability and collaboration

    CERN Document Server

    Lozano, María D; Tesoriero, Ricardo; Penichet, Victor MR

    2013-01-01

    Written by international researchers in the field of Distributed User Interfaces (DUIs), this book brings together important contributions regarding collaboration and usability in Distributed User Interface settings. Throughout the thirteen chapters authors address key questions concerning how collaboration can be improved by using DUIs, including: in which situations a DUI is suitable to ease the collaboration among users; how usability standards can be used to evaluate the usability of systems based on DUIs; and accurately describe case studies and prototypes implementing these concerns

  8. Some Contributions to Nonmonotonic Consequence

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhaohui; ZHANG Dongmo; CHEN Shifu; ZHU Wujia

    2001-01-01

    This paper introduces a non-Horn rule WRM which is a weak form of rational monotony. We explore the effects of adding this non-Horn rule to the rules for the preferential inference. In this paper, a relation |~ is said to be P + WRM iff it is a preferential inference and satisfies the rule WRM. We establish the representation theorem for P+WRM, and compare the strength of WRM with some non-Horn rules appearing in literatures. Moreover, we explore the relation between P+WRM and conditional logic, and demonstrate that P+WRM is equivalent to ‘flat' fragment of conditional logic CS4.2. Another contribution of this paper is to explore the relation between two special kinds of preferential models, i.e., PRC model and quasi-linear model. Main result reveals that the latter is a special form of the former.

  9. Hadron Contribution to Vacuum Polarisation

    Science.gov (United States)

    Davier, M.; Hoecker, A.; Malaescu, B.; Zhang, Z.

    2016-10-01

    Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle-antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e- annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingredients to high precision tests of the Standard Theory.

  10. Hadron Contribution to Vacuum Polarisation

    CERN Document Server

    Davier, M; Malaescu, B; Zhang, Z

    2016-01-01

    Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle–antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e− annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingre...

  11. Minisuperspace models as infrared contributions

    CERN Document Server

    Bojowald, Martin

    2015-01-01

    A direct correspondence of quantum mechanics as a minisuperspace model for a self-interacting scalar quantum-field theory is established by computing, in several models, the infrared contributions to 1-loop effective potentials of Coleman--Weinberg type. A minisuperspace approximation rather than truncation is thereby obtained. By this approximation, the spatial averaging scale of minisuperspace models is identified with an infrared scale (but not a regulator or cut-off) delimiting the modes included in the minisuperspace model. Some versions of the models studied here have discrete space or modifications of the Hamiltonian expected from proposals of loop quantum gravity. They shed light on the question of how minisuperspace models of quantum cosmology can capture features of full quantum gravity. While it is shown that modifications of the Hamiltonian can well be described by minisuperspace truncations, some related phenomena such as signature change, confirmed and clarified here for modified scalar field th...

  12. Factors contributing to adolescent obesity.

    Science.gov (United States)

    Al-Kloub, Manal I; Froelicher, Erika S

    2009-06-01

    Obesity in children is a significant public health concern. The prevalence of overweight and obesity in Jordanian children, and adolescents has increased in the last decade. The consequences of obesity to health in childhood and adulthood have both medical, and economic cost to individuals and society. This paper reviews the factors that contribute to adolescent obesity and emphasizes behavioral and environmental factors. An individual's behaviors such as increased consumption of high caloric foods, increased sedentary activity while decreasing physical activity has been identified as key issues in the development of obesity. Additionally, the current environment in homes, schools, and neighborhoods tend to discourage a healthy lifestyle. A comprehensive approach that involves the whole community is the best strategy for preventing adolescent obesity. Nurses are in a unique position to provide leadership in developing programs for healthier lifestyle choices for adolescents' and adoption of these goals into their daily lives.

  13. Gender differences in ancestral contribution and admixture in Venezuelan populations.

    Science.gov (United States)

    Guerra, D Castro De; Pérez, C Figuera; Izaguirre, M H; Barahona, E Arroyo; Larralde, A Rodríguez; Lugo, M Vívenes De

    2011-06-01

    The origin of the contribution of uniparental heritage were analyzed in 615 samples of individuals proceeding from 13 towns classified according to historic differences in their emergence and development as African-derived, European-derived, and admixed/urban. Mitochondrial and Y-chromosome haplogroups were identified by PCR-restriction fragment length polymorphism. The results were compared with previous estimates of admixture made with autosomal markers and with historic aspects. The results show a predominantly indigenous genetic contribution through the female, being more prevalent in urban populations; the African contribution, although dispersed, presents a larger concentration in the African-derived towns, whereas the European contribution is limited to populations with this origin, reflecting isolation and the conservation of the distribution pattern of genes of the Colonial era. With regard to admixture through males, it is almost exclusively of European origin, whereas the African contribution is basically concentrated in the African-derived towns, and the Amerindian lineages are almost nonexistent. The genome of paternal heredity, as opposed to the autosomal and the mitochondrial, shows a homogeneous pattern of admixture that is independent of the origin of the population studied, suggesting that European genes have been introduced into the Venezuelan population through male immigrations, whereas the indigenous contribution has been preserved in the Venezuelan genetic pool through the women. These results provide evidence of the heterogeneity in the genetic origin of the Venezuelan population, which should be taken into account in forensic and epidemiologic genetic studies.

  14. U.S./Japan burdensharing: constraints to increased Japanese contribution

    OpenAIRE

    Braker, Patrick J.

    1990-01-01

    Approved for public release; distribution is unlimited. This thesis explores issues relevant to U.S./Japan burdensharing. As U.S. defense expenditures are reduced in the 1990's, U.S. allies will be called upon to contribute a greater share to meet common security responsibilities. Japan's government faces a multitude of constraints to increasing defense expenditures placed upon them by the U.S., the Japanese public and Japan's Asian neighbors. Some of these constraints are affected sig...

  15. The Kumaraswamy Laplace Distribution

    Directory of Open Access Journals (Sweden)

    Manal Mohamed Nassar

    2016-12-01

    Full Text Available A generalized Laplace distribution using the Kumaraswamy distribution is introduced. Different structural properties of this new distribution are derived, including the moments, and the moment generating function. We discuss maximum likelihood estimation of the model parameters and obtain the observed and expected information matrix. A real data set is used to compare the new model with widely known distributions.

  16. the impact of distribut impact of distribut impact of distributed ...

    African Journals Online (AJOL)

    eobe

    Keywords: distributed generation; wind energy; integration of renewable sources and technical losses. 1. .... Against this background, the objectives of this paper .... this is the subject of further research. Also the .... biomass, geothermal etc.

  17. Distributed computing for global health

    CERN Document Server

    CERN. Geneva; Schwede, Torsten; Moore, Celia; Smith, Thomas E; Williams, Brian; Grey, François

    2005-01-01

    Distributed computing harnesses the power of thousands of computers within organisations or over the Internet. In order to tackle global health problems, several groups of researchers have begun to use this approach to exceed by far the computing power of a single lab. This event illustrates how companies, research institutes and the general public are contributing their computing power to these efforts, and what impact this may have on a range of world health issues. Grids for neglected diseases Vincent Breton, CNRS/EGEE This talk introduces the topic of distributed computing, explaining the similarities and differences between Grid computing, volunteer computing and supercomputing, and outlines the potential of Grid computing for tackling neglected diseases where there is little economic incentive for private R&D efforts. Recent results on malaria drug design using the Grid infrastructure of the EU-funded EGEE project, which is coordinated by CERN and involves 70 partners in Europe, the US and Russi...

  18. Extended Poisson Exponential Distribution

    Directory of Open Access Journals (Sweden)

    Anum Fatima

    2015-09-01

    Full Text Available A new mixture of Modified Exponential (ME and Poisson distribution has been introduced in this paper. Taking the Maximum of Modified Exponential random variable when the sample size follows a zero truncated Poisson distribution we have derived the new distribution, named as Extended Poisson Exponential distribution. This distribution possesses increasing and decreasing failure rates. The Poisson-Exponential, Modified Exponential and Exponential distributions are special cases of this distribution. We have also investigated some mathematical properties of the distribution along with Information entropies and Order statistics of the distribution. The estimation of parameters has been obtained using the Maximum Likelihood Estimation procedure. Finally we have illustrated a real data application of our distribution.

  19. Contributions to the mammalogy of Chile

    Science.gov (United States)

    Pine, Ronald H.; Miller, Sterling D.; Schamberger, Mel L.

    1979-01-01

    Collections of mammals were made during more than three years of biological investigations in Chile sponsored by the Corporación Nacional Forestal under the aegis of the Peace Corps (Smithsonian Environmental Program). Genera and species hitherto unreported for that country were taken and many useful data concerning distributional patterns of other (mostly little-known) species were gathered. These collections have also proved valuable in better understanding Chilean mammals from a taxonomic point of view and contribute knowledge of the species' natural history. Specimens are to be deposited in the (United States) National Museum of Natural History (USNM) or are to be retained by the Corporación Nacional Forestal, Avda, Bulnes 285, Depto. 401, Santiago. Numbers provided below are field numbers. A final division of specimens between the two institutions has not yet been made. A number of specimens reported here were not taken by Peace Corps personnel but have been obtained by the National Museum of Natural History from other sources. Specimens in the Field Museum of Natural History (FMNH) were used in making comparisons. Some of Fulk's (GWF) specimens are at Texas Tech University. Other are at the Servicio Agricola y Ganadero in Santiago (as are specimens of some introduced species taken by Schamberger). Reise's (DF) are at the Universidad de Chile-Concepción and in his personal collection.

  20. Titan's corona: The contribution of exothermic chemistry

    Science.gov (United States)

    De La Haye, V.; Waite, J. H.; Cravens, T. E.; Nagy, A. F.; Johnson, R. E.; Lebonnois, S.; Robertson, I. P.

    2007-11-01

    The contribution of exothermic ion and neutral chemistry to Titan's corona is studied. The production rates for fast neutrals N 2, CH 4, H, H 2, 3CH 2, CH 3, C 2H 4, C 2H 5, C 2H 6, N( 4S), NH, and HCN are determined using a coupled ion and neutral model of Titan's upper atmosphere. After production, the formation of the suprathermal particles is modeled using a two-stream simulation, as they travel simultaneously through a thermal mixture of N 2, CH 4, and H 2. The resulting suprathermal fluxes, hot density profiles, and energy distributions are compared to the N 2 and CH 4 INMS exospheric data presented in [De La Haye, V., Waite Jr., J.H., Johnson, R.E., Yelle, R.V., Cravens, T.E., Luhmann, J.G., Kasprzak, W.T., Gell, D.A., Magee, B., Leblanc, F., Michael, M., Jurac, S., Robertson, I.P., 2007. J. Geophys. Res., doi:10.1029/2006JA012222, in press], and are found insufficient for producing the suprathermal populations measured. Global losses of nitrogen atoms and carbon atoms in all forms due to exothermic chemistry are estimated to be 8.3×10 Ns and 7.2×10 Cs.

  1. Generalized Lindley Distribution

    Directory of Open Access Journals (Sweden)

    H. Zakerzadeh

    2009-06-01

    Full Text Available In this paper, we introduce a three–parameter generalization of the Lindley distribution. This includes as special cases the exponential and gamma distributions. The distribution exhibits decreasing, increasing and bathtub hazard rate depending on its parameters. We study various properties of the new distribution and provide numerical examples to show the flexibility of the model. We also derive a bivariate version of the proposed distribution.

  2. Distributed Data Management and Distributed File Systems

    CERN Document Server

    Girone, Maria

    2015-01-01

    The LHC program has been successful in part due to the globally distributed computing resources used for collecting, serving, processing, and analyzing the large LHC datasets. The introduction of distributed computing early in the LHC program spawned the development of new technologies and techniques to synchronize information and data between physically separated computing centers. Two of the most challenges services are the distributed file systems and the distributed data management systems. In this paper I will discuss how we have evolved from local site services to more globally independent services in the areas of distributed file systems and data management and how these capabilities may continue to evolve into the future. I will address the design choices, the motivations, and the future evolution of the computing systems used for High Energy Physics.

  3. Applications of species distribution modeling to paleobiology

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Fløjgaard, Camilla; A. Marske, Katharine

    2011-01-01

    Species distribution modeling (SDM: statistical and/or mechanistic approaches to the assessment of range determinants and prediction of species occurrence) offers new possibilities for estimating and studying past organism distributions. SDM complements fossil and genetic evidence by providing (i...... the role of Pleistocene glacial refugia in biogeography and evolution, especially in Europe, but also in many other regions. SDM-based approaches are also beginning to contribute to a suite of other research questions, such as historical constraints on current distributions and diversity patterns, the end...

  4. Dynamic balance control in transfemoral amputees: Individual contribution of the prosthesis side

    NARCIS (Netherlands)

    Nederhand, M.J.; Asseldonk, van E.H.F.; Kooij, van der H.

    2006-01-01

    1. Summary/conclusions This study explores the use of a new developed method to assess the individual contribution of both legs to postural control. The results imply that the contribution of the prosthetic leg in balance control is not a mere reflection of the weight distribution. 2. Introduction

  5. Minisuperspace models as infrared contributions

    Science.gov (United States)

    Bojowald, Martin; Brahma, Suddhasattwa

    2016-06-01

    A direct correspondence of quantum mechanics as a minisuperspace model for a self-interacting scalar quantum-field theory is established by computing, in several models, the infrared contributions to 1-loop effective potentials of Coleman-Weinberg type. A minisuperspace approximation rather than truncation is thereby obtained. By this approximation, the spatial averaging scale of minisuperspace models is identified with an infrared scale (but not a regulator or cutoff) delimiting the modes included in the minisuperspace model. Some versions of the models studied here have discrete space or modifications of the Hamiltonian expected from proposals of loop quantum gravity. They shed light on the question of how minisuperspace models of quantum cosmology can capture features of full quantum gravity. While it is shown that modifications of the Hamiltonian can be well described by minisuperspace truncations, some related phenomena such as signature change, confirmed and clarified here for modified scalar field theories, require at least a perturbative treatment of inhomogeneity beyond a strict minisuperspace model. The new methods suggest a systematic extension of minisuperspace models by a canonical effective formulation of perturbative inhomogeneity.

  6. Quarkonium Contribution to Meson Molecules

    CERN Document Server

    Cincioglu, E; Ozpineci, A; Yilmazer, A U

    2016-01-01

    Starting from a molecular picture for the X(3872) resonance, this state and its J^{PC}=2++ HQSS partner [X2(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium states. Since it is reasonable to expect the bare chi_{c1}(2P) to be located above the D\\bar D* threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to bind the X(3872), but it will not appear in the 2++ sector. Indeed in this latter sector, the chi_{c2}(2P) should provide an effective small repulsion, because it is placed well below the D*\\bar D* threshold. We show how the 1++ and 2++ bare charmonium poles are modified due to the D(*)\\bar D(*) loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the 1++ dressed charmonium state. On the other hand, the X(3872) and X2(4012) start developing some charmonium content, which is estimated by...

  7. Nordic contributions to disability policies.

    Science.gov (United States)

    Kebbon, L

    1997-04-01

    The most spectacular contribution from the nordic countries to intellectual disability policy is probably the idea of normalization, but it is not the simplistic notion that can be inferred from international debate. Its major significance may have been to act as an inspiring catchword for the important trend away from institutions into integrated living. However, it is more fully understood when seen in the concrete context where it has successively developed, and been critically analysed and tested in operation. Scandinavian sociologists and psychologists--as well as politicians--were also among the first to use the concept of quality of life for analysis of social policy, including intellectual disability. The primary medium for implementation has been legislation, where the dominant difficulty is to find a balance between security and freedom, protection and self-determination. Through this process, the role of social engineering in the welfare state, based on humanistic ideas of solidarity, can be followed into today's emphasis on individual influence and participation.

  8. The microbial contribution to macroecology

    Directory of Open Access Journals (Sweden)

    Albert eBarberan

    2014-05-01

    Full Text Available There has been a recent explosion of research within the field of microbial ecology that has been fueled, in part, by methodological improvements that make it feasible to characterize microbial communities to an extent that was inconceivable only a few years ago. Furthermore, there is increasing recognition within the field of ecology that microorganisms play a critical role in the health of organisms and ecosystems. Despite these developments, an important gap still persists between the theoretical framework of macroecology and microbial ecology. We highlight two idiosyncrasies of microorganisms that are fundamental to understanding macroecological patterns and their mechanistic drivers. First, high dispersal rates provide novel opportunities to test the relative importance of niche, stochastic, and historical processes in structuring biological communities. Second, high speciation rates potentially lead to the convergence of ecological and evolutionary time scales. After reviewing these unique aspects, we discuss strategies for improving the conceptual integration of microbes into macroecology. As examples, we discuss the use of phylogenetic ecology as an integrative approach to explore patterns across the tree of life. Then we demonstrate how two general theories of biodiversity (i.e., the recently developed theory of stochastic geometry and the neutral theory can be adapted to microorganisms. We demonstrate how conceptual models that integrate evolutionary and ecological mechanisms can contribute to the unification of microbial ecology and macroecology.

  9. Effect of counterions on lanthanum biosorption by Sargassum polycystum.

    Science.gov (United States)

    Diniz, Vivian; Volesky, Bohumil

    2005-06-01

    The effect of the presence of different anions on the biosorption of La(3+) (Lanthanum) using Sargassum polycystum Ca-loaded biomass was studied in this work. Different types of metal salts were used, such as nitrate, sulphate and chloride. The presence of the anion sulphate decreased the metal uptake for tested pH values of 3--5 when compared to the nitrate and chloride systems. The presence of chloride ions did not seem to interfere with the lanthanum removal. The speciation of lanthanum in solution could explain the differences obtained for the different systems and the Mineql+ program was used for the calculations. A monovalent complex with sulphate and lanthanum was formed that had lower apparent affinity towards the biomass compared to the free trivalent metal ion. The La uptake varied from 0.6 to 1.0 mmol g(-1). The Langmuir model was used to describe quantitatively the sorption isotherms. The addition of sulphuric acid for pH adjustment decreased the metal uptake from lanthanum sulphate solutions when compared to the nitric acid addition. The effect was more pronounced with sulphuric acid due to the formation of complexes.

  10. Divalent counterion-induced condensation of triple-strand DNA.

    Science.gov (United States)

    Qiu, Xiangyun; Parsegian, V Adrian; Rau, Donald C

    2010-12-14

    Understanding and manipulation of the forces assembling DNA/RNA helices have broad implications for biology, medicine, and physics. One subject of significance is the attractive force between dsDNA mediated by polycations of valence ≥ 3. Despite extensive studies, the physical origin of the "like-charge attraction" remains unsettled among competing theories. Here we show that triple-strand DNA (tsDNA), a more highly charged helix than dsDNA, is precipitated by alkaline-earth divalent cations that are unable to condense dsDNA. We further show that our observation is general by examining several cations (Mg(2+), Ba(2+), and Ca(2+)) and two distinct tsDNA constructs. Cation-condensed tsDNA forms ordered hexagonal arrays that redissolve upon adding monovalent salts. Forces between tsDNA helices, measured by osmotic stress, follow the form of hydration forces observed with condensed dsDNA. Probing a well-defined system of point-like cations and tsDNAs with more evenly spaced helical charges, the counterintuitive observation that the more highly charged tsDNA (vs. dsDNA) is condensed by cations of lower valence provides new insights into theories of polyelectrolytes and the biological and pathological roles of tsDNA. Cations and tsDNAs also hold promise as a model system for future studies of DNA-DNA interactions and electrostatic interactions in general.

  11. Estimating individual contributions to population growth: evolutionary fitness in ecological time

    OpenAIRE

    Coulson, T.; Benton, T. G.; Lundberg, Per; Dall, S.R.X.; Kendall, B E; Gaillard, J.M.

    2006-01-01

    Ecological and evolutionary change is generated by variation in individual performance. Biologists have consequently long been interested in decomposing change measured at the population level into contributions from individuals, the traits they express and the alleles they carry. We present a novel method of estimating individual contributions to population growth and changes in distributions of quantitative traits and alleles. An individual's contribution to population growth is an indi...

  12. Exact Random Walk Distributions using Noncommutative Geometry

    CERN Document Server

    Bellissard, J; Barelli, A; Claro, F; Bellissard, Jean; Camacho, Carlos J; Barelli, Armelle; Claro, Francisco

    1997-01-01

    Using the results obtained by the non commutative geometry techniques applied to the Harper equation, we derive the areas distribution of random walks of length $ N $ on a two-dimensional square lattice for large $ N $, taking into account finite size contributions.

  13. 26 CFR 1.722-1 - Basis of contributing partner's interest.

    Science.gov (United States)

    2010-04-01

    ...) INCOME TAX (CONTINUED) INCOME TAXES Contributions, Distributions, and Transfers § 1.722-1 Basis of... partnership capital results in taxable income to a partner, such income shall constitute an addition to the... partners, since the partnership's assumption of his indebtedness is treated as a distribution of money...

  14. Physics of the nucleon sea quark distributions

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, R.

    2000-03-10

    Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However,recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that (bar u) < (bar d) in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

  15. NMDA受体不同亚单位分布造成肌萎缩侧索硬化中运动神经元选择性易损%Different distribution of NMDA receptor subunits in cortex contributs to selective vulnerability of motor neurons in amyotrophic lateral sclerosis

    Institute of Scientific and Technical Information of China (English)

    郑梅; 樊东升

    2011-01-01

    目的:研究NMDA受体不同亚单位NR2A和NR2B分布与肌萎缩侧索硬化中运动神经元选择性易损的关系.方法:首先在离体培养的脑组织片中用谷氦酸转运抑制剂造成兴奋毒性损伤,观察在同等损伤条件下运动皮层和梨状区皮层是否出现有差异的神经元数量减少,然后用Western blot方法测定运动皮层和梨状区皮层的NR2A和NR2B的蛋白含量,证明选择性运动皮层损伤与NR2A和NR2B的不同分布方式有关,为进一步明确NR2A和NR2B在运动神经元谷氨酸慢性损伤中的作用不同,在离体培养的皮层运动神经元和脑组织片中分别抑制NR2A和NR2B,观察对运动神经元产生的影响.结果:用谷氨酸转运抑制剂THA 100 μmol/L损伤脑片2周后,运动皮层神经元的死亡率高于梨状区皮层,分别为64.50%±2.19%和30.43%±4.75%(P<0.01).Western blot结果表明NR2B/NR2A比值在运动皮层明显高于梨状区皮层,分别为0.87±0.09和0.47±0.09(P<0.01).抑制剂保护作用试验中,NR2B抑制剂显示出保护作用,离体培养的皮层运动神经元对照组、谷氨酸损伤组、谷氨酸+NR2A抑制剂组和谷氨酸+NR2B抑制剂组的运动神经元死亡率分别为6.85%±1.47%、47.48%±5.75%、45.76%±8.09%和18.10%±3.11%,脑片对照组、THA损伤组、THA+NR2A抑制剂组和THA+NR2B抑制剂组的运动神经元死亡率分别为12.49%±2.09%、100%、110.87%±15.76%和35.13%±5.32%.结论:NR2A和NR2B在运动神经元慢性谷氨酸损伤中所起的作用不同,NR2B在运动皮层的高分布造成肌萎缩侧索硬化中运动神经元的选择性易损.%Objective : To investigate the relationship between different distribution of NMDA receptor subunits and motor neurons selective vulnerability in amyotrophic lateral sclerosis. Methods : First we investigated whether administration of THA, a glutamate transport inhibitor, in cultured organotypic brain tissue made different damage of motor cortex and piriform cortex

  16. Peripheral contributions to visceral hyperalgesia.

    Science.gov (United States)

    Gebhart, G F

    1999-03-01

    and, along with activated mechanically insensitive receptors, increase the afferent barrage into the spinal cord, contributing to the development of visceral hyperalgesia.

  17. Modified Slash Lindley Distribution

    Directory of Open Access Journals (Sweden)

    Jimmy Reyes

    2017-01-01

    Full Text Available In this paper we introduce a new distribution, called the modified slash Lindley distribution, which can be seen as an extension of the Lindley distribution. We show that this new distribution provides more flexibility in terms of kurtosis and skewness than the Lindley distribution. We derive moments and some basic properties for the new distribution. Moment estimators and maximum likelihood estimators are calculated using numerical procedures. We carry out a simulation study for the maximum likelihood estimators. A fit of the proposed model indicates good performance when compared with other less flexible models.

  18. Hard exclusive reactions and generalized parton distributions

    Directory of Open Access Journals (Sweden)

    Hayrapetyan Avetik

    2015-01-01

    Full Text Available The recently developed formalism of Generalized Parton Distributions (GPDs allows connecting the experimental information of hard exclusive reactions to the spin contribution and even to the angular momentum contribution of quarks in the nucleon. By selecting different quantum numbers of the final state in exclusive productions, different GPDs can be addressed separately. The HERMES experiment at the HERA ring at DESY (Hamburg made pioneering contributions and first constraints to Generalized Parton Distributions (GPDs, using hard exclusive vector meson production (EVMP and Deeply Virtual Compton Scattering (DVCS. Using a novel recoil detector, HERMES managed to measure DVCS and EVMP free of any significant background. Selected results are highlighted and discussed in this paper.

  19. Health, personal responsibility, and distributive justice

    DEFF Research Database (Denmark)

    Andersen, Martin Marchman

    This PhD dissertation is a contribution to discussions about personal responsibility in relation to distributive justice in health and health care. It is a contribution to contemporary political philosophy in general, but in particular to luck egalitarian theory. I aim to answer three focal...... recent political philosophical discussions of responsibility in egalitarian and luck egalitarian theory to bear on issues of social inequality in health, and access to health care. I argue that distributive justice in health and health care should be sensitive to responsibility, but also that individuals...... questions: 1) What role ought personal responsibility to play in distributive justice in health and health care? 2) What does it take for an individual to be responsible for her own health condition (or responsible in general)? And 3) what is the relation between responsibility and cost...

  20. 22 CFR 130.6 - Political contribution.

    Science.gov (United States)

    2010-04-01

    ..., FEES AND COMMISSIONS § 130.6 Political contribution. Political contribution means any loan, gift... solicitation or promotion or otherwise to secure the conclusion of a sale of defense articles or defense...

  1. Quarkonium Contribution to Meson Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cincioglu, E.; Yilmazer, A.U. [Ankara University, Department of Physics Engineering, Ankara (Turkey); Nieves, J. [Instituto de Fisica Corpuscular (IFIC) Centro Mixto CSIC-Universidad de Valencia, Institutos de Investigacion de Paterna, Valencia (Spain); Ozpineci, A. [Middle East Technical University, Department of Physics, Ankara (Turkey)

    2016-10-15

    Starting from a molecular picture for the X(3872) resonance, this state and its J{sup PC} = 2{sup ++} heavy-quark spin symmetry partner [X{sub 2}(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium (c anti c) states. Since it is reasonable to expect the bare χ{sub c1}(2P) to be located above the D anti D{sup *} threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to binding the X(3872), but it will not appear in the 2{sup ++} sector. Indeed in the latter sector, the χ{sub c2}(2P) should provide an effective small repulsion, because it is placed well below the D{sup *} anti D{sup *} threshold. We show how the 1{sup ++} and 2{sup ++} bare charmonium poles are modified due to the D{sup (*)} anti D{sup (*)} loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the 1{sup ++} dressed charmonium state. On the other hand, X(3872) and X{sub 2}(4012) start developing some charmonium content, which is estimated by means of the compositeness Weinberg sum rule. It turns out that in the heavy-quark limit, there is only one coupling between the 2P charmonia and the D{sup (*)} anti D{sup (*)} pairs. We also show that, for reasonable values of this coupling, leading to X(3872) molecular probabilities of around 70-90 %, the X{sub 2} resonance destabilizes and disappears from the spectrum, becoming either a virtual state or one being located deep into the complex plane, with decreasing influence in the D{sup *} anti D{sup *} scattering line. Moreover, we also discuss how around 10-30 % charmonium probability in the X(3872) might explain the ratio of radiative decays of this resonance into ψ(2S)γ and J/ψγ. Finally, we qualitatively discuss within this scheme, the hidden bottom flavor sector, paying a special attention to the implications for the X{sub b} and X

  2. The GMOS contributions to GEOSS

    Directory of Open Access Journals (Sweden)

    Pirrone N.

    2013-04-01

    oceans, and in the UTLS will support the validation of regional and global atmospheric mercury models for use in evaluating different policy options for reducing mercury pollution and its impacts on human health and ecosystems. The data sets, the validated models, and the interoperable system that is produced within this program, will support the policymaking process in the framework of UNEP Governing Council activities, and in the UNECE-LRTAP convention. The task builds upon contributions from, among others, the Global Mercury Observation System (GMOS project, the UNEP Mercury Programme, the Hemispheric Transport of Air Pollutants Task Force (TF HTAP, the European Monitoring and Evaluation Program (EMEP, the MercNet/AMNet initiative in the USA, the CAMNet in Canada, and other international monitoring and modelling efforts.

  3. 12 CFR 1291.2 - Required annual AHP contributions; allocation of contributions.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Required annual AHP contributions; allocation... GOALS AND MISSION FEDERAL HOME LOAN BANKS' AFFORDABLE HOUSING PROGRAM § 1291.2 Required annual AHP contributions; allocation of contributions. (a) Annual AHP contributions. Each Bank shall contribute annually...

  4. Hyperfinite Representation of Distributions

    Indian Academy of Sciences (India)

    J Sousa Pinto; R F Hoskins

    2000-11-01

    Hyperfinite representation of distributions is studied following the method introduced by Kinoshita [2, 3], although we use a different approach much in the vein of [4]. Products and Fourier transforms of representatives of distributions are also analysed.

  5. Distributed computer control systems

    Energy Technology Data Exchange (ETDEWEB)

    Suski, G.J.

    1986-01-01

    This book focuses on recent advances in the theory, applications and techniques for distributed computer control systems. Contents (partial): Real-time distributed computer control in a flexible manufacturing system. Semantics and implementation problems of channels in a DCCS specification. Broadcast protocols in distributed computer control systems. Design considerations of distributed control architecture for a thermal power plant. The conic toolset for building distributed systems. Network management issues in distributed control systems. Interprocessor communication system architecture in a distributed control system environment. Uni-level homogenous distributed computer control system and optimal system design. A-nets for DCCS design. A methodology for the specification and design of fault tolerant real time systems. An integrated computer control system - architecture design, engineering methodology and practical experience.

  6. Drinking Water Distribution Systems

    Science.gov (United States)

    Learn about an overview of drinking water distribution systems, the factors that degrade water quality in the distribution system, assessments of risk, future research about these risks, and how to reduce cross-connection control risk.

  7. Predictable return distributions

    DEFF Research Database (Denmark)

    Pedersen, Thomas Quistgaard

    This paper provides detailed insights into predictability of the entire stock and bond return distribution through the use of quantile regression. This allows us to examine speci…c parts of the return distribution such as the tails or the center, and for a suf…ciently …ne grid of quantiles we can...... are predictable as a function of economic state variables. The results are, however, very different for stocks and bonds. The state variables primarily predict only location shifts in the stock return distribution, while they also predict changes in higher-order moments in the bond return distribution. Out...... trace out the entire distribution. A univariate quantile regression model is used to examine stock and bond return distributions individually, while a multivariate model is used to capture their joint distribution. An empirical analysis on US data shows that certain parts of the return distributions...

  8. 26 CFR 1.408-8 - Distribution requirements for individual retirement plans.

    Science.gov (United States)

    2010-04-01

    ... Roth IRA. Q-2. Are IRAs that receive employer contributions under a simplified employee pension... contributed to a Roth IRA that is a conversion contribution or failed conversion contribution and that amount... from Roth IRAs (defined in section 408A) will not satisfy the distribution requirements applicable...

  9. Intelligent Distributed Computing V : Proceedings of the 5th International Symposium on Intelligent Distributed Computing

    CERN Document Server

    Nieuwenhuis, Kees; Pavlin, Gregor; Warnier, Martijn; Badica, Costin

    2012-01-01

    This book represents the combined peer-reviewed proceedings of the Fifth International Symposium on Intelligent Distributed Computing -- IDC 2011 and of the Third International Workshop on Multi-Agent Systems Technology and Semantics -- MASTS 2011. Both events were held in Delft, The Netherlands during October 5-7, 2011. The 33 contributions published in this book address many topics related to theory and applications of intelligent distributed computing and multi-agent systems, including: adaptive and autonomous distributed systems, agent programming, ambient assisted living systems, business process modeling and verification, cloud computing, coalition formation, decision support systems, distributed optimization and constraint satisfaction, gesture recognition, intelligent energy management in WSNs, intelligent logistics, machine learning, mobile agents, parallel and distributed computational intelligence, parallel evolutionary computing, trust metrics and security, scheduling in distributed heterogenous c...

  10. Analyzing Distributed Generation Impact on the Reliability of Electric Distribution Network

    Directory of Open Access Journals (Sweden)

    Sanaullah Ahmad

    2016-10-01

    Full Text Available With proliferation of Distribution Generation (DG and renewable energy technologies the power system is becoming more complex, with passage of time the development of distributed generation technologies is becoming diverse and broad. Power system reliability is one of most vital area in electric power system which deals with continuous supply of power and customer satisfaction. Distribution network in power system contributed up to 80% of reliability problems. This paper analyzes the impact of Wind Turbine Generator (WTG as a distribution generation source on reliability of distribution system. Injecting single WTG and close to load point has positive impact on reliability, while injecting multiple WTGs at single place has adverse impact on distribution system reliability. These analyses are performed on bus 2 of Roy Billinton Test System (RBTS.

  11. Intelligent Distributed Systems

    Science.gov (United States)

    2015-10-23

    AFRL-AFOSR-VA-TR-2016-0006 Intelligent Distributed Systems A Stephen Morse YALE UNIV NEW HAVEN CT Final Report 10/23/2015 DISTRIBUTION A...and D. Fullmer. A distributed algorithm for efficiently solving linear equations and its applications. System and Control Letters, 2015. submitted... Distribution approved for public release. AF Office Of Scientific Research (AFOSR)/ RTA2 Arlington, Virginia 22203 Air Force Research Laboratory Air Force

  12. Centralized and distributed architectures of scalable video conferencing services

    OpenAIRE

    Le, Tien Anh; Nguyen, Hang

    2010-01-01

    International audience; The Multipoint Control Unit-based centralized architecture and Application Layer Multicast-based distributed architecture are mainly used for data distribution in video conferencing services. With the contribution of Scalable Video Coding, the latest extension of Advanced Video Coding, video conferencing services are being further researched to support terminals' scalability. The main contribution of this research is to answer a fundamental question before a video conf...

  13. Leadership for Distributed Teams

    NARCIS (Netherlands)

    De Rooij, J.P.G.

    2009-01-01

    The aim of this dissertation was to study the little examined, yet important issue of leadership for distributed teams. Distributed teams are defined as: “teams of which members are geographically distributed and are therefore working predominantly via mediated communication means on an

  14. Leadership for Distributed Teams

    NARCIS (Netherlands)

    De Rooij, J.P.G.

    2009-01-01

    The aim of this dissertation was to study the little examined, yet important issue of leadership for distributed teams. Distributed teams are defined as: “teams of which members are geographically distributed and are therefore working predominantly via mediated communication means on an interdepende

  15. Probability distributions for magnetotellurics

    Energy Technology Data Exchange (ETDEWEB)

    Stodt, John A.

    1982-11-01

    Estimates of the magnetotelluric transfer functions can be viewed as ratios of two complex random variables. It is assumed that the numerator and denominator are governed approximately by a joint complex normal distribution. Under this assumption, probability distributions are obtained for the magnitude, squared magnitude, logarithm of the squared magnitude, and the phase of the estimates. Normal approximations to the distributions are obtained by calculating mean values and variances from error propagation, and the distributions are plotted with their normal approximations for different percentage errors in the numerator and denominator of the estimates, ranging from 10% to 75%. The distribution of the phase is approximated well by a normal distribution for the range of errors considered, while the distribution of the logarithm of the squared magnitude is approximated by a normal distribution for a much larger range of errors than is the distribution of the squared magnitude. The distribution of the squared magnitude is most sensitive to the presence of noise in the denominator of the estimate, in which case the true distribution deviates significantly from normal behavior as the percentage errors exceed 10%. In contrast, the normal approximation to the distribution of the logarithm of the magnitude is useful for errors as large as 75%.

  16. Energy Inputs Uncertainty: Total Amount, Distribution and Correlation Between Different Forms of Energy

    Science.gov (United States)

    Deng, Yue

    2014-01-01

    Describes solar energy inputs contributing to ionospheric and thermospheric weather processes, including total energy amounts, distributions and the correlation between particle precipitation and Poynting flux.

  17. Extreme value distributions

    CERN Document Server

    Ahsanullah, Mohammad

    2016-01-01

    The aim of the book is to give a through account of the basic theory of extreme value distributions. The book cover a wide range of materials available to date. The central ideas and results of extreme value distributions are presented. The book rwill be useful o applied statisticians as well statisticians interrested to work in the area of extreme value distributions.vmonograph presents the central ideas and results of extreme value distributions.The monograph gives self-contained of theory and applications of extreme value distributions.

  18. Verification of LHS distributions.

    Energy Technology Data Exchange (ETDEWEB)

    Swiler, Laura Painton

    2006-04-01

    This document provides verification test results for normal, lognormal, and uniform distributions that are used in Sandia's Latin Hypercube Sampling (LHS) software. The purpose of this testing is to verify that the sample values being generated in LHS are distributed according to the desired distribution types. The testing of distribution correctness is done by examining summary statistics, graphical comparisons using quantile-quantile plots, and format statistical tests such as the Chisquare test, the Kolmogorov-Smirnov test, and the Anderson-Darling test. The overall results from the testing indicate that the generation of normal, lognormal, and uniform distributions in LHS is acceptable.

  19. 26 CFR 1.704-1 - Partner's distributive share.

    Science.gov (United States)

    2010-04-01

    ....704-1(b)(2)(iv)(d) In general 1.704-1(b)(2)(iv)(d)(1) Contribution of promissory notes 1.704-1(b)(2... imposed by the partnership agreement or by State or local law) to make subsequent contributions to the... the purpose of winding up its affairs, paying its debts, and distributing any remaining balance to its...

  20. 26 CFR 53.4942(a)-3 - Qualifying distributions defined.

    Science.gov (United States)

    2010-04-01

    ... contribution to: (a) A private foundation which is not an operating foundation (as defined in section 4942(j)(3... distribution, since it is a contribution for section 170(c)(2)(B) purposes to an organization which is not... month period for paying the amount set aside may, for good cause shown, be extended by the Commissioner...

  1. Wealth distribution models: analisys and applications

    Directory of Open Access Journals (Sweden)

    Camilo Dagum

    2008-03-01

    Full Text Available After Pareto developed his Type I model in 1895, a large number of income distribution models have been specified. However, the important issue of wealth distribution called the attention of researchers more than sixty years later. It started with the contributions by Wold and Whittle, and Sargan, both published in 1957. The former authors proposed the Pareto Type I model and the latter the lognormal distribution, but they did not empirically validate them. Afterward, other models were proposed: in 1969 the Pareto Types I and II by Stiglitz; in 1975, the loglogistic by Atkinson and the Pearson Type V by Vaughan. In 1990 and 1994, Dagum developed a general model and his type II as models of wealth distribution. They were validated with real life data from the U.S.A., Canada, Italy and the U.K. In 1999, Dagum further developed his general model of net wealth distribution with support (??,? which contains, as particular cases, his Types I and II model of income and wealth distributions. This study presents and analyzes the proposed models of wealth distribution and their properties. The only model with the flexibility, power, and economic and stochastic foundations to accurately fit net and total wealth distributions is the Dagum general model and its particular cases as validated with the case studies of Ireland, U.K., Italy and U.S.A.

  2. Distributed security in closed distributed systems

    DEFF Research Database (Denmark)

    Hernandez, Alejandro Mario

    reflected in heterogeneous security aims; the software life cycle entails evolution and this includes security expectations; the distribution is useful if the entire system is “open” to new (a priori unknown) interactions; the distribution itself poses intrinsically more complex security-related problems......, and aim at providing security to each of these individually. The approach taken is by means of access control enforcement mechanisms, providing security to the locations they are related to. We provide a framework for modelling so. All this follows techniques borrowed from the aspect-orientation community....... As this needs to be scaled up to the entire distributed system, we then focus on ways of reasoning about the resulting composition of these individual access control mechanisms. We show how, by means of relying on the semantics of our framework, we can syntactically guarantee some limited set of global security...

  3. Positive and negative contribution to birefringence in a family of carbonates: A Born effective charges analysis

    Science.gov (United States)

    Jing, Qun; Yang, Guang; Hou, Juan; Sun, Maozhu; Cao, Haibin

    2016-12-01

    It is an important topic to investigate the birefringence and reveal the contribution from ions to birefringence because it plays an important role in nonlinear optical materials. In this paper, the birefringence of carbonates with coplanar CO3 groups were investigated using the first-principles method. The results show that the lead carbonates exhibit relative large birefringence. After detailed investigate the electronic structures, and Born effective charges, the authors find out that anisotropic electron distribution in the CO3 groups and Pb atoms give positive contribution, while the negative contribution was found from fluorine atoms, meanwhile the Ca, Mg, and Cd atoms give very small contribution to birefringence.

  4. Linearly Polarized Gluons and the Higgs Transverse Momentum Distribution

    NARCIS (Netherlands)

    Boer, Daniel; den Dunnen, Wilco J.; Pisano, Cristian; Schlegel, Marc; Vogelsang, Werner

    2012-01-01

    We study how gluons carrying linear polarization inside an unpolarized hadron contribute to the transverse momentum distribution of Higgs bosons produced in hadronic collisions. They modify the distribution produced by unpolarized gluons in a characteristic way that could be used to determine whethe

  5. Error Variance of Rasch Measurement with Logistic Ability Distributions.

    Science.gov (United States)

    Dimitrov, Dimiter M.

    Exact formulas for classical error variance are provided for Rasch measurement with logistic distributions. An approximation formula with the normal ability distribution is also provided. With the proposed formulas, the additive contribution of individual items to the population error variance can be determined without knowledge of the other test…

  6. Baryon octet distribution amplitudes in Wandzura-Wilczek approximation

    Energy Technology Data Exchange (ETDEWEB)

    Anikin, I.V. [Joint Institute of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics; Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Manashov, A.N. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2015-12-15

    We study higher twist distribution amplitudes for the SU{sub F}(3) baryon octet. We identify independent functions for all baryons in the isospin symmetry limit and calculate the Wandzura-Wilczek contributions to the twist-4 and 5 distributions amplitudes.

  7. Aid Distribution and Co-operation in Unequal Communities

    NARCIS (Netherlands)

    Exelle, D' B.; Berg, van den M.M.

    2012-01-01

    We study the influence of economic inequality on co-operation and aid distribution in community-based development schemes. For this, we organized a field experiment in which community members contributed to a collective effort to attract aid. We find that devolving aid distribution to community repr

  8. A model for the distribution channels planning process

    NARCIS (Netherlands)

    Neves, M.F.; Zuurbier, P.; Campomar, M.C.

    2001-01-01

    Research of existing literature reveals some models (sequence of steps) for companies that want to plan distribution channels. None of these models uses strong contributions from transaction cost economics, bringing a possibility to elaborate on a "distribution channels planning model", with these c

  9. STUDY OF AETIOLOGICAL FACTORS CONTRIBUTING TO PAEDIATRIC STRABISMUS

    Directory of Open Access Journals (Sweden)

    B. Dharmaraju

    2016-08-01

    Full Text Available AIMS AND OBJECTIVES To know various causes, sex distribution, socioeconomic status, onset, severity, visual prognosis of paediatric strabismus. METHODOLOGY The present study was undertaken for a period of 18 months. All the patients were selected from those attending the outpatient department. 50 cases of squint were evaluated thoroughly to know the various factors responsible for squint and how it was caused. RESULTS Total Number of Patients who attended OPD were 72,431 (4000 per month. Total Number of Paediatric squint cases among them were 121. So, Incidence of Paediatric squint in general OP was-0.16%. In the present study of total 121 paediatric squint cases, 21 cases did not fulfil the inclusion criteria and in the remaining 100, cases were included by taking every 2nd patient. Esotropia is seen in 38 children contributing to 76% of total and exotropia is seen in 12 children contributing 24% of total cases. Most common cause of esotropia is Essential Infantile Esotropia contributing to 31% of total esotropias. Males are affected more commonly than females with an incidence of 60%. Esotropia is seen in 38 children contributing to 76% of total and exotropia is seen in 12 children contributing 24% of total cases. In this study, males are affected more commonly than females contributing to 60% of total and females constitute 40% of the total. In this study, incidence of paediatric squint is more commonly seen in lower socioeconomic population contributing 60% of the total. 15 cases are of congenital in onset constituting 30% of total and 35 cases are of acquired in onset constituting 70% of total. Small angle Esotropia and large angle Esotropia: In this study out of total 38 cases of esotropia, large angle esotropias are more common and contributing to 89% of the total. Out of total 50 cases, 16% had an angle of 30⁰. Out of 50 cases, significant family history was present in 15 cases contributing to 30% of total cases. Following early

  10. Testing the ability of a semidistributed hydrological model to simulate contributing area

    Science.gov (United States)

    Mengistu, S. G.; Spence, C.

    2016-06-01

    A dry climate, the prevalence of small depressions, and the lack of a well-developed drainage network are characteristics of environments with extremely variable contributing areas to runoff. These types of regions arguably present the greatest challenge to properly understanding catchment streamflow generation processes. Previous studies have shown that contributing area dynamics are important for streamflow response, but the nature of the relationship between the two is not typically understood. Furthermore, it is not often tested how well hydrological models simulate contributing area. In this study, the ability of a semidistributed hydrological model, the PDMROF configuration of Environment Canada's MESH model, was tested to determine if it could simulate contributing area. The study focused on the St. Denis Creek watershed in central Saskatchewan, Canada, which with its considerable topographic depressions, exhibits wide variation in contributing area, making it ideal for this type of investigation. MESH-PDMROF was able to replicate contributing area derived independently from satellite imagery. Daily model simulations revealed a hysteretic relationship between contributing area and streamflow not apparent from the less frequent remote sensing observations. This exercise revealed that contributing area extent can be simulated by a semi-distributed hydrological model with a scheme that assumes storage capacity distribution can be represented with a probability function. However, further investigation is needed to determine if it can adequately represent the complex relationship between streamflow and contributing area that is such a key signature of catchment behavior.

  11. Leadership for Distributed Teams

    OpenAIRE

    De Rooij, J.P.G.

    2009-01-01

    The aim of this dissertation was to study the little examined, yet important issue of leadership for distributed teams. Distributed teams are defined as: “teams of which members are geographically distributed and are therefore working predominantly via mediated communication means on an interdependent task and in realizing a joint goal” (adapted from Bell & Kozlowski, 2002 and Dubé & Paré, 2004). Chapter 1 first presents the outline of the dissertation. Next, several characteristics of distri...

  12. Distributed generation systems model

    Energy Technology Data Exchange (ETDEWEB)

    Barklund, C.R.

    1994-12-31

    A slide presentation is given on a distributed generation systems model developed at the Idaho National Engineering Laboratory, and its application to a situation within the Idaho Power Company`s service territory. The objectives of the work were to develop a screening model for distributed generation alternatives, to develop a better understanding of distributed generation as a utility resource, and to further INEL`s understanding of utility concerns in implementing technological change.

  13. Deciding bisimilarities on distributions

    DEFF Research Database (Denmark)

    Eisentraut, Christian; Hermanns, Holger; Krämer, Julia

    2013-01-01

    Probabilistic automata (PA) are a prominent compositional concurrency model. As a way to justify property-preserving abstractions, in the last years, bisimulation relations over probability distributions have been proposed both in the strong and the weak setting. Different to the usual bisimulati...... is known so far. This paper presents an equivalent state-based reformulation for weak distribution bisimulation, rendering it amenable for algorithmic treatment. Then, decision procedures for the probability distribution-based bisimulation relations are presented....

  14. [Original contributions of Latin Americans to anesthesiology].

    Science.gov (United States)

    Aldrete, J A

    1998-10-01

    The original contributions of Latin American physicians to the science of anesthesiology are described. Many contributions have been unfairly ignored mainly because they were never published in English, but others have likewise been passed over even when published in the most prestigious journals in the field. Although many discoveries by Latin Americans have been made in the area of regional anesthesia, a considerable number of contributions have involved other aspects of anesthesia as well.

  15. IDENTIFYING KEY CONTRIBUTIONS TO INFORMATION SCIENCE,

    Science.gov (United States)

    Several alternative approaches were examined to determine how one might identify some of the key (written) contributions to ’ information science ’. The...references. The unclear selective patterns in current bibliographies in the information science field also present problems. It is suggested that in...identifying key contributions we are far from common agreement on the conceptual, methodological or practical contributions to the information science field

  16. Sorting a distribution theory

    CERN Document Server

    Mahmoud, Hosam M

    2011-01-01

    A cutting-edge look at the emerging distributional theory of sorting Research on distributions associated with sorting algorithms has grown dramatically over the last few decades, spawning many exact and limiting distributions of complexity measures for many sorting algorithms. Yet much of this information has been scattered in disparate and highly specialized sources throughout the literature. In Sorting: A Distribution Theory, leading authority Hosam Mahmoud compiles, consolidates, and clarifies the large volume of available research, providing a much-needed, comprehensive treatment of the

  17. Parton Distribution Function Uncertainties

    CERN Document Server

    Giele, Walter T.; Kosower, David A.; Giele, Walter T.; Keller, Stephane A.; Kosower, David A.

    2001-01-01

    We present parton distribution functions which include a quantitative estimate of its uncertainties. The parton distribution functions are optimized with respect to deep inelastic proton data, expressing the uncertainties as a density measure over the functional space of parton distribution functions. This leads to a convenient method of propagating the parton distribution function uncertainties to new observables, now expressing the uncertainty as a density in the prediction of the observable. New measurements can easily be included in the optimized sets as added weight functions to the density measure. Using the optimized method nowhere in the analysis compromises have to be made with regard to the treatment of the uncertainties.

  18. Advanced air distribution

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2011-01-01

    The aim of total volume air distribution (TVAD) involves achieving uniform temperature and velocity in the occupied zone and environment designed for an average occupant. The supply of large amounts of clean and cool air are needed to maintain temperature and pollution concentration at acceptable....... Ventilation in hospitals is essential to decrease the risk of airborne cross-infection. At present, mixing air distribution at a minimum of 12 ach is used in infection wards. Advanced air distribution has the potential to aid in achieving healthy, comfortable and productive indoor environments at levels...... higher than what can be achieved today with the commonly used total volume air distribution principles....

  19. Electric distribution systems

    CERN Document Server

    Sallam, A A

    2010-01-01

    "Electricity distribution is the penultimate stage in the delivery of electricity to end users. The only book that deals with the key topics of interest to distribution system engineers, Electric Distribution Systems presents a comprehensive treatment of the subject with an emphasis on both the practical and academic points of view. Reviewing traditional and cutting-edge topics, the text is useful to practicing engineers working with utility companies and industry, undergraduate graduate and students, and faculty members who wish to increase their skills in distribution system automation and monitoring."--

  20. Distributed Energy Technology Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Distributed Energy Technologies Laboratory (DETL) is an extension of the power electronics testing capabilities of the Photovoltaic System Evaluation Laboratory...

  1. Distributed Structure Searchable Toxicity

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Distributed Structure Searchable Toxicity (DSSTox) online resource provides high quality chemical structures and annotations in association with toxicity data....

  2. groundwater contribution to crop water requirement groundwater ...

    African Journals Online (AJOL)

    eobe

    Keywords: Groundwater, water table, capillary rise, soil type, waterleaf, ... GROUNDWATER CONTRIBUTION TO WATERLEAF (TALINUM TRIANGULARE) IN OXISOLS, I. J. ... Nutritionally, ... information to facilitate increased crop production,.

  3. Intelligent Distributed Computing VI : Proceedings of the 6th International Symposium on Intelligent Distributed Computing

    CERN Document Server

    Badica, Costin; Malgeri, Michele; Unland, Rainer

    2013-01-01

    This book represents the combined peer-reviewed proceedings of the Sixth International Symposium on Intelligent Distributed Computing -- IDC~2012, of the International Workshop on Agents for Cloud -- A4C~2012 and of the Fourth International Workshop on Multi-Agent Systems Technology and Semantics -- MASTS~2012. All the events were held in Calabria, Italy during September 24-26, 2012. The 37 contributions published in this book address many topics related to theory and applications of intelligent distributed computing and multi-agent systems, including: adaptive and autonomous distributed systems, agent programming, ambient assisted living systems, business process modeling and verification, cloud computing, coalition formation, decision support systems, distributed optimization and constraint satisfaction, gesture recognition, intelligent energy management in WSNs, intelligent logistics, machine learning, mobile agents, parallel and distributed computational intelligence, parallel evolutionary computing, trus...

  4. Control Scheme for Distributed Generator Providing Network Voltage Support

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The distributed generator over the last 30 years has posed several challenges when they are connected to a distributed network. The most immediate problem is to change the voltage at the connection point depending on the power supplied to the network and may cause it to exceed statutory limits. This paper describes a new control scheme for a distributed generator for supporting the voltage control in the network, thus ensuring the distributed generator to contribute to network voltage management. The scheme performance is demonstrated by a model for a distributed generator connected to a distribution network. The result shows that using the new control scheme, the distribution network voltage constraints are maintained while maximizing the active power delivered by distributed generators.

  5. Quality, safety and sustainability in food distribution

    DEFF Research Database (Denmark)

    Akkerman, Renzo; Farahani, Poorya; Grunow, Martin

    2010-01-01

    The management of food distribution networks is receiving more and more attention, both in practice and in the scientific literature. In this paper, we review quantitative operations management approaches to food distribution management, and relate this to challenges faced by the industry. Here......, our main focus is on three aspects: food quality, food safety, and sustainability. We discuss the literature on three decision levels: strategic network design, tactical network planning and operational transportation planning. For each of these, we survey the research contributions, discuss the state...

  6. Bi-log-concave Distribution Functions

    DEFF Research Database (Denmark)

    Dümbgen, Lutz; Kolesnyk, Petro; Wilke, Ralf

    2017-01-01

    Nonparametric statistics for distribution functions F or densities f=F′ under qualitative shape constraints constitutes an interesting alternative to classical parametric or entirely nonparametric approaches. We contribute to this area by considering a new shape constraint: F is said to be bi......-log-concave, if both logF and log(1−F) are concave. Many commonly considered distributions are compatible with this constraint. For instance, any c.d.f. F with log-concave density f=F′ is bi-log-concave. But in contrast to log-concavity of f, bi-log-concavity of F allows for multimodal densities. We provide various...

  7. Embodied and Distributed Parallel DJing.

    Science.gov (United States)

    Cappelen, Birgitta; Andersson, Anders-Petter

    2016-01-01

    Everyone has a right to take part in cultural events and activities, such as music performances and music making. Enforcing that right, within Universal Design, is often limited to a focus on physical access to public areas, hearing aids etc., or groups of persons with special needs performing in traditional ways. The latter might be people with disabilities, being musicians playing traditional instruments, or actors playing theatre. In this paper we focus on the innovative potential of including people with special needs, when creating new cultural activities. In our project RHYME our goal was to create health promoting activities for children with severe disabilities, by developing new musical and multimedia technologies. Because of the users' extreme demands and rich contribution, we ended up creating both a new genre of musical instruments and a new art form. We call this new art form Embodied and Distributed Parallel DJing, and the new genre of instruments for Empowering Multi-Sensorial Things.

  8. Vestigial-like 2 contributes to normal muscle fiber type distribution in mice.

    Science.gov (United States)

    Honda, Masahiko; Hidaka, Kyoko; Fukada, So-Ichiro; Sugawa, Ryo; Shirai, Manabu; Ikawa, Masahito; Morisaki, Takayuki

    2017-08-02

    Skeletal muscle is composed of heterogeneous populations of myofibers that are classified as slow- and fast-twitch fibers. The muscle fiber-type is regulated in a coordinated fashion by multiple genes, including transcriptional factors and microRNAs (miRNAs). However, players involved in this regulation are not fully elucidated. One of the members of the Vestigial-like factors, Vgll2, is thought to play a pivotal role in TEA domain (TEAD) transcription factor-mediated muscle-specific gene expression because of its restricted expression in skeletal muscles of adult mice. Here, we generated Vgll2 null mice and investigated Vgll2 function in adult skeletal muscles. These mice presented an increased number of fast-twitch type IIb fibers and exhibited a down-regulation of slow type I myosin heavy chain (MyHC) gene, Myh7, which resulted in exercise intolerance. In accordance with the decrease in Myh7, down-regulation of miR-208b, encoded within Myh7 gene and up-regulation of targets of miR-208b, Sox6, Sp3, and Purβ, were observed in Vgll2 deficient mice. Moreover, we detected the physical interaction between Vgll2 and TEAD1/4 in neonatal skeletal muscles. These results suggest that Vgll2 may be both directly and indirectly involved in the programing of slow muscle fibers through the formation of the Vgll2-TEAD complex.

  9. An Analysis of Lessons in Self-Management. The specific issue of contributions and resource distribution

    Directory of Open Access Journals (Sweden)

    Ana Inés Heras Monner Sans

    2015-06-01

    Full Text Available Results from a collaborative ethnographic and sociolinguistic study are presented to analyze lessons in self-managed organizations in contemporary Argentina. We build on Bleger´s (2007 classic definition of “learning” in order to construct an inter-disciplinary analytical frame to interpret the specific characteristics found in these groups, according to their general orientation towards autonomy as a human project (Castoriadis, 1997, 2007. Our analysis shows the complexities associated to this framework, as well as the specific abilities that are continually learned by participants within self-management as an organizational context.

  10. A contribution to the data on tench (Tinca tinca L., Cyprinidae, pisces distribution in Serbia

    Directory of Open Access Journals (Sweden)

    Marković Goran S.

    2010-01-01

    Full Text Available The studies on the ichthyofauna of Serbia that have been conducted so far indicate the sporadic tench (Tinca tinca L. presence in typical habitats. The hydroenvironmental conditions necessary for the survival of this fish species are highly variable and, generally, are more favourable in the northern part of the country (the Vojvodina Province. Although the tench presence has been registered at over 30 sites, there is a tendency of a decrease in population abundance. This is due to the reduction of the surface area of the macrophyte-covered flood zones induced by the damming and regulation of rivers, high water level fluctuations, and water amount reduction in the majority of watercourses, a massive increase in the number of allochthonous phytofagous species, reservoir sediment deposition, water quality deterioration and other factors. The tench conservation status in Serbia is officially designated as Low Risk - Least Concern. It may be transferred to a higher category if the tendency towards deterioration of survival conditions for the species should continue.

  11. 1 Contribution of land use to rodent flea load distribution in the ...

    African Journals Online (AJOL)

    Land use and human activities have been reported to be important ... affect the ecology of fleas living on and momentarily off-host is still lacking (Hubbart et al., 2011). ...... marine metapopulations: modelling infectious diseases on coral reefs.

  12. Ecological characteristics contribute to sponge distribution and tool use in bottlenose dolphins Tursiops sp.

    NARCIS (Netherlands)

    Tyne, Julian A.; Loneragan, Neil R.; Kopps, Anna M.; Allen, Simon J.; Kruetzen, Michael; Bejder, Lars

    2012-01-01

    In Shark Bay, Western Australia, bottlenose dolphins Tursiops sp. carry conical sponges Echinodictyum mesenterinum on their rostra in the only documented cetacean foraging behaviour using a tool ('sponging'). In this study, we examined the influence of various ecological factors on live sponge distr

  13. Ecological characteristics contribute to sponge distribution and tool use in bottlenose dolphins Tursiops sp.

    NARCIS (Netherlands)

    Tyne, Julian A.; Loneragan, Neil R.; Kopps, Anna M.; Allen, Simon J.; Kruetzen, Michael; Bejder, Lars

    2012-01-01

    In Shark Bay, Western Australia, bottlenose dolphins Tursiops sp. carry conical sponges Echinodictyum mesenterinum on their rostra in the only documented cetacean foraging behaviour using a tool ('sponging'). In this study, we examined the influence of various ecological factors on live sponge distr

  14. Contribution to the distribution of terrestrial small mammals in the Sǎlaj county, Romania

    Directory of Open Access Journals (Sweden)

    Gubányi A.

    2016-03-01

    Full Text Available During the research period (2014-2015 287 small mammals, five species of shrews and eight species of rodents (Crocidura leucodon, C. suaveolens, Sorex araneus, S. minutus, Neomys anomalus, Microtus agrestis M. arvalis, M. subterraneus, Myodes glareolus. Apodemus agrarius, A. flavicollis, A. sylvaticus, A. uralensis were detected in the Sǎlaj County. The striped field mouse (Apodemus agrarius and the common vole (Microtus arvalis proved to be the characteristic dominant species of the small mammal communities investigated in this area. The number of terrestrial small mammalian species lagged behind our expectations. Micromys minutus was not collected during the research period in the habitats characterized by reed-bed and/or tall sedge vegetation.

  15. Smart Distribution Systems

    Directory of Open Access Journals (Sweden)

    Yazhou Jiang

    2016-04-01

    Full Text Available The increasing importance of system reliability and resilience is changing the way distribution systems are planned and operated. To achieve a distribution system self-healing against power outages, emerging technologies and devices, such as remote-controlled switches (RCSs and smart meters, are being deployed. The higher level of automation is transforming traditional distribution systems into the smart distribution systems (SDSs of the future. The availability of data and remote control capability in SDSs provides distribution operators with an opportunity to optimize system operation and control. In this paper, the development of SDSs and resulting benefits of enhanced system capabilities are discussed. A comprehensive survey is conducted on the state-of-the-art applications of RCSs and smart meters in SDSs. Specifically, a new method, called Temporal Causal Diagram (TCD, is used to incorporate outage notifications from smart meters for enhanced outage management. To fully utilize the fast operation of RCSs, the spanning tree search algorithm is used to develop service restoration strategies. Optimal placement of RCSs and the resulting enhancement of system reliability are discussed. Distribution system resilience with respect to extreme events is presented. Test cases are used to demonstrate the benefit of SDSs. Active management of distributed generators (DGs is introduced. Future research in a smart distribution environment is proposed.

  16. Metrics for Food Distribution.

    Science.gov (United States)

    Cooper, Gloria S., Ed.; Magisos, Joel H., Ed.

    Designed to meet the job-related metric measurement needs of students interested in food distribution, this instructional package is one of five for the marketing and distribution cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already know the occupational…

  17. Epicentral distribution in 2007

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei-shan

    2008-01-01

    @@ For showing the epicentral distribution in and near China as well as all over the world, two epicentral maps for the earthquakes occurred last year are published annually in the 6-th issue each year. Figures 1 and 2 represent the epicentral distributions in and near China and all over the World in 2007, Respectively.

  18. Epicentral distribution in 2004

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei-shan

    2005-01-01

    @@ For showing the epicentral distribution in and near China as well as all over the world, two epicentral maps for the earthquakes occurred last year are published annually in the 6-th issue each year. Figures 1 and 2 represent the epicentral distributions in and near China and all over the world in 2004, respectively.

  19. Epicentral distribution in 2005

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei-shan

    2006-01-01

    @@ For showing the epicentral distribution in and near China as well as all over the world, two epicentral maps for the earthquakes occurred last year are published annually in the 6-th issue each year. Figures 1 and 2 represent the epicentral distributions in and near China and all over the world in 2005, respectively.

  20. Epicentral distribution in 2006

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei-shan

    2007-01-01

    @@ For showing the epicentral distribution in and near China as well as all over the world, two epicentral maps for the earthquakes occurred last year are published annually in the 6-th issue each year. Figures 1 and 2 represent the epicentral distributions in and near China and all over the world in 2006, respectively.

  1. Distribution Functions of Copulas

    Institute of Scientific and Technical Information of China (English)

    LI Yong-hong; He Ping

    2007-01-01

    A general method was proposed to evaluate the distribution function of 〈C1|C2〉 . Some examples were presented to validate the application of the method. Then the sufficient and necessary condition for that the distribution function ofis uniform was proved.

  2. Distributed Control Diffusion

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh

    2007-01-01

    , self-reconfigurable robots, we present the concept of distributed control diffusion: distributed queries are used to identify modules that play a specific role in the robot, and behaviors that implement specific control strategies are diffused throughout the robot based on these role assignments...... perform simple obstacle avoidance in a wide range of different car-like robots constructed using ATRON modules...

  3. Advanced Distribution Management System

    Science.gov (United States)

    Avazov, Artur R.; Sobinova, Liubov A.

    2016-02-01

    This article describes the advisability of using advanced distribution management systems in the electricity distribution networks area and considers premises of implementing ADMS within the Smart Grid era. Also, it gives the big picture of ADMS and discusses the ADMS advantages and functionalities.

  4. Software distribution using xnetlib

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J.J. [Univ. of Tennessee, Knoxville, TN (US). Dept. of Computer Science]|[Oak Ridge National Lab., TN (US); Rowan, T.H. [Oak Ridge National Lab., TN (US); Wade, R.C. [Univ. of Tennessee, Knoxville, TN (US). Dept. of Computer Science

    1993-06-01

    Xnetlib is a new tool for software distribution. Whereas its predecessor netlib uses e-mail as the user interface to its large collection of public-domain mathematical software, xnetlib uses an X Window interface and socket-based communication. Xnetlib makes it easy to search through a large distributed collection of software and to retrieve requested software in seconds.

  5. Property insurance loss distributions

    Science.gov (United States)

    Burnecki, Krzysztof; Kukla, Grzegorz; Weron, Rafał

    2000-11-01

    Property claim services (PCS) provides indices for losses resulting from catastrophic events in the US. In this paper, we study these indices and take a closer look at distributions underlying insurance claims. Surprisingly, the lognormal distribution seems to give a better fit than the Paretian one. Moreover, lagged autocorrelation study reveals a mean-reverting structure of indices returns.

  6. Distributed Energy Implementation Options

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Chandralata N [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-13

    This presentation covers the options for implementing distributed energy projects. It distinguishes between options available for distributed energy that is government owned versus privately owned, with a focus on the privately owned options including Energy Savings Performance Contract Energy Sales Agreements (ESPC ESAs). The presentation covers the new ESPC ESA Toolkit and other Federal Energy Management Program resources.

  7. Distributed operating systems

    NARCIS (Netherlands)

    Mullender, Sape J.

    1987-01-01

    In the past five years, distributed operating systems research has gone through a consolidation phase. On a large number of design issues there is now considerable consensus between different research groups. In this paper, an overview of recent research in distributed systems is given. In turn, th

  8. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  9. Quantum dense key distribution

    CERN Document Server

    Degiovanni, I P; Castelletto, S; Rastello, M L; Bovino, F A; Colla, A M; Castagnoli, G C

    2004-01-01

    This paper proposes a new protocol for quantum dense key distribution. This protocol embeds the benefits of a quantum dense coding and a quantum key distribution and is able to generate shared secret keys four times more efficiently than BB84 one. We hereinafter prove the security of this scheme against individual eavesdropping attacks, and we present preliminary experimental results, showing its feasibility.

  10. Electrical Distribution Program Guide.

    Science.gov (United States)

    Georgia Univ., Athens. Dept. of Vocational Education.

    This program guide contains the standard electrical distribution curriculum for technical institutes in Georgia. The curriculum encompasses the minimum competencies required for entry-level workers in the electrical distribution field, and in job skills such as construction, maintenance, and repair of overhead and underground electrical…

  11. Groundwater and Distribution Workbook.

    Science.gov (United States)

    Ekman, John E.

    Presented is a student manual designed for the Wisconsin Vocational, Technical and Adult Education Groundwater and Distribution Training Course. This program introduces waterworks operators-in-training to basic skills and knowledge required for the operation of a groundwater distribution waterworks facility. Arranged according to the general order…

  12. Distributed System Evaluation

    Science.gov (United States)

    1990-07-01

    computers. If a distributed operating system is designed with aschrony in mind efficient usage of overall system resources can be employed through the...the complex problem of efficiently balancing CPU, disk, and communications resource usage in the distributed environment mast be solved by the...throughput (concuirent processing capability), survivability and availabilty , and finally interprocess communication. In measuning the concurrent

  13. Pore size distribution mapping

    OpenAIRE

    Strange, John H.; J. Beau W. WEBBER; Schmidt, S.D.

    1996-01-01

    Pore size distribution mapping has been demonstrated using NMR cryoporometry\\ud in the presence of a magnetic field gradient, This novel method is extendable to 2D and 3D mapping. It offers a unique nondestructive method of obtaining full pore-size distributions in the range 3 to 100 nm at any point within a bulk sample. \\ud

  14. Cache Oblivious Distribution Sweeping

    DEFF Research Database (Denmark)

    Brodal, G.S.; Fagerberg, R.

    2002-01-01

    We adapt the distribution sweeping method to the cache oblivious model. Distribution sweeping is the name used for a general approach for divide-and-conquer algorithms where the combination of solved subproblems can be viewed as a merging process of streams. We demonstrate by a series of algorithms...

  15. Health, personal responsibility, and distributive justice

    DEFF Research Database (Denmark)

    Andersen, Martin Marchman

    recent political philosophical discussions of responsibility in egalitarian and luck egalitarian theory to bear on issues of social inequality in health, and access to health care. I argue that distributive justice in health and health care should be sensitive to responsibility, but also that individuals...... explains why we have justice-based reasons to reduce social inequality in health. In my second article I investigate and (partly) object to a suggestion put forward by Shlomi Segall, according to which we should exchange the notion of responsibility with a notion of Reasonable Avoidability in the luck......This PhD dissertation is a contribution to discussions about personal responsibility in relation to distributive justice in health and health care. It is a contribution to contemporary political philosophy in general, but in particular to luck egalitarian theory. I aim to answer three focal...

  16. Contribution of Renewables to Energy Security

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The environmental benefits of renewable energy are well known. But the contribution that they can make to energy security is less widely recognised. This report aims to redress the balance, showing how in electricity generation, heat supply, and transport, renewables can enhance energy security and suggesting policies that can optimise this contribution.

  17. Factors Contributing to Institutions Achieving Environmental Sustainability

    Science.gov (United States)

    James, Matthew; Card, Karen

    2012-01-01

    Purpose: The purpose of this paper is to determine what factors contributed to three universities achieving environmental sustainability. Design/methodology/approach: A case study methodology was used to determine how each factor contributed to the institutions' sustainability. Site visits, fieldwork, document reviews, and interviews with…

  18. 45 CFR 1326.9 - Contributions.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION ON AGING, OLDER AMERICANS PROGRAMS GRANTS TO INDIAN TRIBES FOR SUPPORT AND NUTRITION SERVICES § 1326.9 Contributions. (a) Each tribal organization... nutrition services contributions only to expand services as provided under section 307(a)(13)(c)(ii) of the...

  19. Contributions of Psychology to War and Peace

    Science.gov (United States)

    Christie, Daniel J.; Montiel, Cristina J.

    2013-01-01

    The contributions of American psychologists to war have been substantial and responsive to changes in U.S. national security threats and interests for nearly 100 years. These contributions are identified and discussed for four periods of armed conflict: World Wars I and II, the Cold War, and the Global War on Terror. In contrast, about 50 years…

  20. The economic contribution of tourism in Mozambique

    DEFF Research Database (Denmark)

    Jones, Edward Samuel

    2010-01-01

    How much tourism contributes to the economies of developing countries is controversial and often not measured rigorously. Focusing on Mozambique, this study presents a simple accounting tool – a tourist-focused Social Accounting Matrix – which makes it possible to estimate the economic contribution...

  1. 31 CFR 547.408 - Charitable contributions.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Charitable contributions. 547.408 Section 547.408 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... REGULATIONS Interpretations § 547.408 Charitable contributions. Unless specifically authorized by the Office...

  2. Factors Contributing to Institutions Achieving Environmental Sustainability

    Science.gov (United States)

    James, Matthew; Card, Karen

    2012-01-01

    Purpose: The purpose of this paper is to determine what factors contributed to three universities achieving environmental sustainability. Design/methodology/approach: A case study methodology was used to determine how each factor contributed to the institutions' sustainability. Site visits, fieldwork, document reviews, and interviews with…

  3. 13 CFR 120.912 - Borrowed contributions.

    Science.gov (United States)

    2010-01-01

    ... borrow its cash contribution from the CDC or a third party. If any of the contribution is borrowed, the interest rate must be reasonable. If the loan is secured by any of the Project assets, the loan must be subordinate to the liens securing the 504 Loan, and the loan may not be repaid at a faster rate than the...

  4. Distributed Robotics Education

    DEFF Research Database (Denmark)

    Lund, Henrik Hautop; Pagliarini, Luigi

    2011-01-01

    Distributed robotics takes many forms, for instance, multirobots, modular robots, and self-reconfigurable robots. The understanding and development of such advanced robotic systems demand extensive knowledge in engineering and computer science. In this paper, we describe the concept...... of a distributed educational system as a valuable tool for introducing students to interactive parallel and distributed processing programming as the foundation for distributed robotics and human-robot interaction development. This is done by providing an educational tool that enables problem representation...... to be changed, related to multirobot control and human-robot interaction control from virtual to physical representation. The proposed system is valuable for bringing a vast number of issues into education – such as parallel programming, distribution, communication protocols, master dependency, connectivity...

  5. Distributed plot-making

    DEFF Research Database (Denmark)

    Jensen, Lotte Groth; Bossen, Claus

    2016-01-01

    different socio-technical systems (paper-based and electronic patient records). Drawing on the theory of distributed cognition and narrative theory, primarily inspired by the work done within health care by Cheryl Mattingly, we propose that the creation of overview may be conceptualised as ‘distributed plot......-making’. Distributed cognition focuses on the role of artefacts, humans and their interaction in information processing, while narrative theory focuses on how humans create narratives through the plot construction. Hence, the concept of distributed plot-making highlights the distribution of information processing...... between different social actors and artefacts, as well as the filtering, sorting and ordering of such information into a narrative that is made coherent by a plot. The analysis shows that the characteristics of paper-based and electronic patient records support or obstruct the creation of overview in both...

  6. Fast Distributed Gradient Methods

    CERN Document Server

    Jakovetic, Dusan; Moura, Jose M F

    2011-01-01

    The paper proposes new fast distributed optimization gradient methods and proves convergence to the exact solution at rate O(\\log k/k), much faster than existing distributed optimization (sub)gradient methods with convergence O(1/\\sqrt{k}), while incurring practically no additional communication nor computation cost overhead per iteration. We achieve this for convex (with at least one strongly convex,) coercive, three times differentiable and with Lipschitz continuous first derivative (private) cost functions. Our work recovers for distributed optimization similar convergence rate gains obtained by centralized Nesterov gradient and fast iterative shrinkage-thresholding algorithm (FISTA) methods over ordinary centralized gradient methods. We also present a constant step size distributed fast gradient algorithm for composite non-differentiable costs. A simulation illustrates the effectiveness of our distributed methods.

  7. Development of distributed target

    CERN Document Server

    Yu Hai Jun; Li Qin; Zhou Fu Xin; Shi Jin Shui; Ma Bing; Chen Nan; Jing Xiao Bing

    2002-01-01

    Linear introduction accelerator is expected to generate small diameter X-ray spots with high intensity. The interaction of the electron beam with plasmas generated at the X-ray converter will make the spot on target increase with time and debase the X-ray dose and the imaging resolving power. A distributed target is developed which has about 24 pieces of thin 0.05 mm tantalum films distributed over 1 cm. due to the structure adoption, the distributed target material over a large volume decreases the energy deposition per unit volume and hence reduces the temperature of target surface, then reduces the initial plasma formalizing and its expansion velocity. The comparison and analysis with two kinds of target structures are presented using numerical calculation and experiments, the results show the X-ray dose and normalized angle distribution of the two is basically the same, while the surface of the distributed target is not destroyed like the previous block target

  8. Distributed Analysis in CMS

    CERN Document Server

    Fanfani, Alessandra; Sanches, Jose Afonso; Andreeva, Julia; Bagliesi, Giusepppe; Bauerdick, Lothar; Belforte, Stefano; Bittencourt Sampaio, Patricia; Bloom, Ken; Blumenfeld, Barry; Bonacorsi, Daniele; Brew, Chris; Calloni, Marco; Cesini, Daniele; Cinquilli, Mattia; Codispoti, Giuseppe; D'Hondt, Jorgen; Dong, Liang; Dongiovanni, Danilo; Donvito, Giacinto; Dykstra, David; Edelmann, Erik; Egeland, Ricky; Elmer, Peter; Eulisse, Giulio; Evans, Dave; Fanzago, Federica; Farina, Fabio; Feichtinger, Derek; Fisk, Ian; Flix, Josep; Grandi, Claudio; Guo, Yuyi; Happonen, Kalle; Hernandez, Jose M; Huang, Chih-Hao; Kang, Kejing; Karavakis, Edward; Kasemann, Matthias; Kavka, Carlos; Khan, Akram; Kim, Bockjoo; Klem, Jukka; Koivumaki, Jesper; Kress, Thomas; Kreuzer, Peter; Kurca, Tibor; Kuznetsov, Valentin; Lacaprara, Stefano; Lassila-Perini, Kati; Letts, James; Linden, Tomas; Lueking, Lee; Maes, Joris; Magini, Nicolo; Maier, Gerhild; McBride, Patricia; Metson, Simon; Miccio, Vincenzo; Padhi, Sanjay; Pi, Haifeng; Riahi, Hassen; Riley, Daniel; Rossman, Paul; Saiz, Pablo; Sartirana, Andrea; Sciaba, Andrea; Sekhri, Vijay; Spiga, Daniele; Tuura, Lassi; Vaandering, Eric; Vanelderen, Lukas; Van Mulders, Petra; Vedaee, Aresh; Villella, Ilaria; Wicklund, Eric; Wildish, Tony; Wissing, Christoph; Wurthwein, Frank

    2009-01-01

    The CMS experiment expects to manage several Pbytes of data each year during the LHC programme, distributing them over many computing sites around the world and enabling data access at those centers for analysis. CMS has identified the distributed sites as the primary location for physics analysis to support a wide community with thousands potential users. This represents an unprecedented experimental challenge in terms of the scale of distributed computing resources and number of user. An overview of the computing architecture, the software tools and the distributed infrastructure is reported. Summaries of the experience in establishing efficient and scalable operations to get prepared for CMS distributed analysis are presented, followed by the user experience in their current analysis activities.

  9. Perspective has a strong effect on the calculation of historical contributions to global warming

    Science.gov (United States)

    Skeie, Ragnhild B.; Fuglestvedt, Jan; Berntsen, Terje; Peters, Glen P.; Andrew, Robbie; Allen, Myles; Kallbekken, Steffen

    2017-02-01

    The politically contentious issue of calculating countries’ contributions to climate change is strongly dependent on methodological choices. Different principles can be applied for distributing efforts for reducing human-induced global warming. According to the ‘Brazilian Proposal’, industrialized countries would reduce emissions proportional to their historical contributions to warming. This proposal was based on the assumption that the political process would lead to a global top-down agreement. The Paris Agreement changed the role of historical responsibilities. Whereas the agreement refers to equity principles, differentiation of mitigation efforts is delegated to each country, as countries will submit new national contributions every five years without any international negotiation. It is likely that considerations of historical contributions and distributive fairness will continue to play a key role, but increasingly so in a national setting. Contributions to warming can be used as a background for negotiations to inform and justify positions, and may also be useful for countries’ own assessment of what constitutes reasonable and fair contributions to limiting warming. Despite the fact that the decision from COP21 explicitly rules out compensation in the context of loss and damage, it is likely that considerations of historical responsibility will also play a role in future discussions. However, methodological choices have substantial impacts on calculated contributions to warming, including rank-ordering of contributions, and thus support the view that there is no single correct answer to the question of how much each country has contributed. There are fundamental value-related and ethical questions that cannot be answered through a single set of calculated contributions. Thus, analyses of historical contributions should not present just one set of results, but rather present a spectrum of results showing how the calculated contributions vary with a

  10. HEALTH INSURANCE: CONTRIBUTIONS AND REIMBURSEMENT MAXIMAL

    CERN Multimedia

    HR Division

    2000-01-01

    Affected by both the salary adjustment index on 1.1.2000 and the evolution of the staff members and fellows population, the average reference salary, which is used as an index for fixed contributions and reimbursement maximal, has changed significantly. An adjustment of the amounts of the reimbursement maximal and the fixed contributions is therefore necessary, as from 1 January 2000.Reimbursement maximalThe revised reimbursement maximal will appear on the leaflet summarising the benefits for the year 2000, which will soon be available from the divisional secretariats and from the AUSTRIA office at CERN.Fixed contributionsThe fixed contributions, applicable to some categories of voluntarily insured persons, are set as follows (amounts in CHF for monthly contributions):voluntarily insured member of the personnel, with complete coverage:815,- (was 803,- in 1999)voluntarily insured member of the personnel, with reduced coverage:407,- (was 402,- in 1999)voluntarily insured no longer dependent child:326,- (was 321...

  11. HEALTH INSURANCE: FIXED CONTRIBUTION AND REIMBURSEMENT MAXIMA

    CERN Multimedia

    Human Resources Division

    2001-01-01

    Affected by the salary adjustments on 1 January 2001 and the evolution of the staff members and fellows population, the average reference salary, which is used as an index for fixed contributions and reimbursement maxima, has changed significantly. An adjustment of the amounts of the reimbursement maxima and the fixed contributions is therefore necessary, as from 1 January 2001. Reimbursement maxima The revised reimbursement maxima will appear on the leaflet summarizing the benefits for the year 2001, which will be sent out with the forthcoming issue of the CHIS Bull'. This leaflet will also be available from the divisional secretariats and from the UNIQA office at CERN. Fixed contributions The fixed contributions, applicable to some categories of voluntarily insured persons, are set as follows (amounts in CHF for monthly contributions) : voluntarily insured member of the personnel, with normal health insurance cover : 910.- (was 815.- in 2000) voluntarily insured member of the personnel, with reduced heal...

  12. Possibility of Large EW Penguin contribution

    CERN Document Server

    Mishima, S; Mishima, Satoshi; Yoshikawa, Tadashi

    2005-01-01

    We discuss a possibility of large electroweak(EW) penguin contribution in B-->K pi and pi pi. The recent experimental data may be still suggesting that there are some discrepancies between the data and theoretical estimations. In B --> K pi decays, to explain several theoretical relations among the branching ratios, a slightly large electroweak penguin contribution and large strong phase differences or quite large color suppressed tree contribution seem to be needed. The contributions should appear also in B --> pi pi. We show, as an example, a solution to solve the discrepancies in both B --> K pi and B --> pi pi. It may be suggesting to need the large electroweak penguin contribution with new weak phases and some SU(3) breaking effects by new physics in both QCD and electroweak penguin type processes.

  13. The World Distribution of Household Wealth

    OpenAIRE

    James B. Davies; Sandström, Susanna; Shorrocks, Anthony; Wolff, Edward N.

    2007-01-01

    There has been much recent research on the world distribution of income, but also growing recognition of the importance of other contributions to well-being, including those of household wealth. Wealth is important in providing security and opportunity, particularly in poorer countries that lack full social safety nets and adequate facilities for borrowing and lending. We find, however, that it is precisely in the latter countries where household wealth is the lowest, both in absolute and rel...

  14. Remanent and induced contributions of the Earth's magnetization

    Science.gov (United States)

    Vervelidou, Foteini; Lesur, Vincent; Thébault, Erwan; Dyment, Jérôme; Holschneider, Matthias

    2016-04-01

    Inverting the magnetic field of crustal origin for the magnetization distribution that generates it suffers from non-uniqueness. The reason for this is the so-called annihilators, i.e. structures that produce no visible magnetic field outside the sources. Gubbins et al., 2011 uses the complex vector Spherical Harmonics notation in order to separate the Vertical Integrated Magnetization (VIM) distribution into the parts that do and do not contribute to the magnetic field measured in source free regions. We use their formalism and convert a crustal SH model based on the WDMAM into a model for the equivalent magnetization. However, we extend their formalism and assume that the magnetization is confined within a layer of finite thickness. A different thickness is considered for the oceanic crust than for the continental one. It is well known that the large scales of the crustal field are entirely masked by the Earth's main field. Therefore, we complement the WDMAM based magnetization map (SH degrees 16 to 800) with the magnetization map for the large wavelengths (SH degrees 1-15) that was recently derived by Vervelidou and Thébault (2015) from a series of regional statistical analyses of the World Digital Magnetic Anomaly Map. Finally we propose a tentative separation of this magnetization map into induced and remanent contributions on a regional scale. We do so based on the direction of the core magnetic field. We discuss the implications of these results in terms of the tectonic history of the Earth.

  15. Distributed Propulsion Vehicles

    Science.gov (United States)

    Kim, Hyun Dae

    2010-01-01

    Since the introduction of large jet-powered transport aircraft, the majority of these vehicles have been designed by placing thrust-generating engines either under the wings or on the fuselage to minimize aerodynamic interactions on the vehicle operation. However, advances in computational and experimental tools along with new technologies in materials, structures, and aircraft controls, etc. are enabling a high degree of integration of the airframe and propulsion system in aircraft design. The National Aeronautics and Space Administration (NASA) has been investigating a number of revolutionary distributed propulsion vehicle concepts to increase aircraft performance. The concept of distributed propulsion is to fully integrate a propulsion system within an airframe such that the aircraft takes full synergistic benefits of coupling of airframe aerodynamics and the propulsion thrust stream by distributing thrust using many propulsors on the airframe. Some of the concepts are based on the use of distributed jet flaps, distributed small multiple engines, gas-driven multi-fans, mechanically driven multifans, cross-flow fans, and electric fans driven by turboelectric generators. This paper describes some early concepts of the distributed propulsion vehicles and the current turboelectric distributed propulsion (TeDP) vehicle concepts being studied under the NASA s Subsonic Fixed Wing (SFW) Project to drastically reduce aircraft-related fuel burn, emissions, and noise by the year 2030 to 2035.

  16. Ruin Distributions and Their Equations

    Institute of Scientific and Technical Information of China (English)

    卢金余; 王汉兴; 赵飞

    2005-01-01

    In this paper, the ruin distributions were analyzed, Including the distribution of surplus immediately before ruin, the distribution of claim at the time of ruin, the distribution of deficit, and the distribution of surplus at the beginning of the claim period before ruin. Several Integral equations for the ruin distributions were derived and some solutions under special conditions were obtained.

  17. Gluon contribution to the structure function $g_{2}(x,Q^{2})$

    CERN Document Server

    Braun, V M; Manashov, A N

    2001-01-01

    We calculate the one-loop twist-3 gluon contribution to the flavor-singlet structure function g_2(x,Q^2) in polarized deep-inelastic scattering and find that it is dominated by the contribution of the three-gluon operator with the lowest anomalous dimension (for each moment N). The similar property was observed earlier for the nonsinglet distributions, although the reason is in our case different. The result is encouraging and suggests a simple evolution pattern of g_2(x,Q^2) in analogy with the conventional description of twist-2 parton distributions.

  18. Restructuring local distribution services: Possibilities and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Duann, D.J.

    1994-08-01

    The restructuring of local distribution services is now the focus of the natural gas industry. It is the last major step in the ``reconstitution`` of the natural gas industry and a critical clement in realizing the full benefits of regulatory and market reforms that already have taken place in the wellhead and interstate markets. It could also be the most important regulatory initiative for most end-use customers because they are affected directly by the costs and reliability of distribution services. Several factors contribute to the current emphasis on distribution service restructuring. They include the unbundling and restructuring of upstream markets, a realization of the limitations of supply-side options (such as gas procurement oversight), and the increased diversity and volatility of gas demand facing local distribution companies. Local distribution service is not one but a series of activities that start with commodity gas procurement and extend to transportation, load balancing, storage, and metering and billing of services provided. There are also considerable differences in the economies of scale and scope associated with these various activities. Thus, a mixture of supply arrangements (such as a competitive market or a monopoly) is required for the most efficient delivery of local distribution services. A distinction must be made between the supply of commodity gas and the provision of a bundled distribution service. This distinction and identification of the best supply arrangements for various distribution service components are the most critical factors in developing appropriate restructuring policies. For most state public utility commissions the criteria for service restructuring should include pursuing the economies of scale and scope in gas distribution, differentiating and matching gas service reliability and quality with customer requirements, and controlling costs associated with the search, negotiation, and contracting of gas services.

  19. Agile distributed software development

    DEFF Research Database (Denmark)

    Persson, John Stouby; Mathiassen, Lars; Aaen, Ivan

    2012-01-01

    While face-to-face interaction is fundamental in agile software development, distributed environments must rely extensively on mediated interactions. Practicing agile principles in distributed environments therefore poses particular control challenges related to balancing fixed vs. evolving quality...... requirements and people vs. process-based collaboration. To investigate these challenges, we conducted an in-depth case study of a successful agile distributed software project with participants from a Russian firm and a Danish firm. Applying Kirsch’s elements of control framework, we offer an analysis of how...

  20. Distributions an outline

    CERN Document Server

    Marchand, Jean-Paul

    2007-01-01

    In a simple but mathematically coherent manner, this text examines the basis of the distribution theories devised by Schwartz and by Mikusinki. Rigorous and concise, it surveys the functional theory of distributions as well as the algebraic theory. Its easy generalizations offer applications to a wide variety of problems.The two-part treatment begins with the functional theory of distributions, exploring differentiation, formation of products, translation and regularization, convergence, Fourier transforms, and partial differential equations. The second half focuses on the algebraic theory of

  1. Electric power distribution handbook

    CERN Document Server

    Short, Thomas Allen

    2003-01-01

    Of the ...big three... components of the electricity infrastructure, distribution typically gets the least attention, and no thorough, up-to-date treatment of the subject has been published in years. Filling that void, the Electric Power Distribution Handbook provides comprehensive information on the electrical aspects of power distribution systems. It is an unparalleled source for the background information, hard-to-find tables, graphs, methods, and statistics that power engineers need, and includes tips and solutions for problem solving and improving performance. In short, this handbook giv

  2. Electric power distribution handbook

    CERN Document Server

    Short, Thomas Allen

    2014-01-01

    Of the ""big three"" components of electrical infrastructure, distribution typically gets the least attention. In fact, a thorough, up-to-date treatment of the subject hasn't been published in years, yet deregulation and technical changes have increased the need for better information. Filling this void, the Electric Power Distribution Handbook delivers comprehensive, cutting-edge coverage of the electrical aspects of power distribution systems. The first few chapters of this pragmatic guidebook focus on equipment-oriented information and applications such as choosing transformer connections,

  3. Theodore Millon's Contributions to Conceptualizing Personality Disorders.

    Science.gov (United States)

    Pincus, Aaron L; Krueger, Robert F

    2015-01-01

    We review Theodore Millon's contributions to conceptualizing personality disorders in contemporary clinical science and practice. Millon worked tirelessly across professional domains and theoretical orientations, developing a rich integrative theory of personality and its pathology, directly and indirectly impacting the evolving iterations of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III through DSM-5), and advocating for the personality disorders through his contributions to cofounding the International Society for the Study of Personality Disorders and the Journal of Personality Disorders. We conclude with a closer look at Millon's final major contributions to conceptualizing personality disorders as well as the strengths and limitations of his approach.

  4. The economic contribution of tourism in Mozambique

    DEFF Research Database (Denmark)

    Jones, Edward Samuel

    2010-01-01

    How much tourism contributes to the economies of developing countries is controversial and often not measured rigorously. Focusing on Mozambique, this study presents a simple accounting tool – a tourist-focused Social Accounting Matrix – which makes it possible to estimate the economic contribution...... of various tourism sub-types. Multiplier analysis is applied to evaluate the strength of backward linkages from tourism to the domestic economy. The results show the sector is moderate in size but has the potential to contribute significantly to aggregate economic development. However, potential weaknesses...

  5. On the Conditional Distribution of the Multivariate $t$ Distribution

    OpenAIRE

    Ding, Peng

    2016-01-01

    As alternatives to the normal distributions, $t$ distributions are widely applied in robust analysis for data with outliers or heavy tails. The properties of the multivariate $t$ distribution are well documented in Kotz and Nadarajah's book, which, however, states a wrong conclusion about the conditional distribution of the multivariate $t$ distribution. Previous literature has recognized that the conditional distribution of the multivariate $t$ distribution also follows the multivariate $t$ ...

  6. Vascular distribution patterns in monochorionic twin placentas.

    Science.gov (United States)

    De Paepe, M E; DeKoninck, P; Friedman, R M

    2005-07-01

    Several recent publications have focused on the association between the occurrence of twin-to-twin transfusion syndrome (TTTS) in diamniotic-monochorionic twins and the presence of a number of selected anatomic placental characteristics (distribution of vascular territory, cord insertion, type and number of inter-twin anastomoses). In contrast, the potential importance of the vascular distribution patterns of the individual twins remains to be elucidated. Based on its gross architectural distribution pattern, chorionic vasculature is traditionally described as disperse, magistral or mixed. The aim of this study was (1) to determine the relative prevalence of these vascular distribution patterns in monochorionic twin placentas, and (2) to correlate these patterns with the presence of TTTS and known anatomic placental features linked to TTTS. The placentas of 89 consecutive diamniotic-monochorionic twins (15 with TTTS, 74 without TTTS), examined at Women and Infants Hospital, were studied. Disperse vascular patterns were seen in 53% of twins, and magistral or mixed patterns in 47%. The prevalence of magistral/mixed vascular patterns was significantly higher in TTTS gestations than in non-TTTS gestations (60% versus 44%, Ppatterns and marginal/velamentous cord insertion, low number of inter-twin anastomoses, and uneven distribution of the vascular territories. These findings suggest that the magistral/mixed vascular distribution pattern may represent an important placental architectural feature contributing to the complex pathophysiology of TTTS.

  7. Nonthermal and suprathermal distributions as a consequence of superstatistics.

    Science.gov (United States)

    Ourabah, Kamel; Ait Gougam, Leila; Tribeche, Mouloud

    2015-01-01

    We propose to put the well-known nonthermal and suprathermal empirical distributions, used in plasma physics, onto a more rigorous foundation. Their use is frequently criticized because of a lack of formal derivation and physical explanation. A connection between these non-Maxwellian distributions and the Beck-Cohen superstatistics is suggested. They are perceived as a consequence of typical temperature fluctuations. We show that the suprathermal distribution is generated by the Γ distribution of the inverse temperature, in the same way as the Tsallis q statistics. The nonthermal distribution also follows from the χ(2) distribution, with a small variance. Our contribution provides a possible physical meaning for these ad hoc distributions.

  8. Pax7 lineage contributions to the mammalian neural crest.

    Directory of Open Access Journals (Sweden)

    Barbara Murdoch

    Full Text Available Neural crest cells are vertebrate-specific multipotent cells that contribute to a variety of tissues including the peripheral nervous system, melanocytes, and craniofacial bones and cartilage. Abnormal development of the neural crest is associated with several human maladies including cleft/lip palate, aggressive cancers such as melanoma and neuroblastoma, and rare syndromes, like Waardenburg syndrome, a complex disorder involving hearing loss and pigment defects. We previously identified the transcription factor Pax7 as an early marker, and required component for neural crest development in chick embryos. In mammals, Pax7 is also thought to play a role in neural crest development, yet the precise contribution of Pax7 progenitors to the neural crest lineage has not been determined.Here we use Cre/loxP technology in double transgenic mice to fate map the Pax7 lineage in neural crest derivates. We find that Pax7 descendants contribute to multiple tissues including the cranial, cardiac and trunk neural crest, which in the cranial cartilage form a distinct regional pattern. The Pax7 lineage, like the Pax3 lineage, is additionally detected in some non-neural crest tissues, including a subset of the epithelial cells in specific organs.These results demonstrate a previously unappreciated widespread distribution of Pax7 descendants within and beyond the neural crest. They shed light regarding the regionally distinct phenotypes observed in Pax3 and Pax7 mutants, and provide a unique perspective into the potential roles of Pax7 during disease and development.

  9. Community Based Distribution

    African Journals Online (AJOL)

    Community Based Distribution (CBD) is a relatively new concept. It is a service that reaches ... neration; Resupply systems; Pricing of contraceptives; Mix of services ... tion on how best to design and implement the project and the community in ...

  10. Bearded Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) of the two subspecies of bearded seals (Erignathus barbatus). It was...

  11. Spotted Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) and reported breeding areas of spotted seals (Phoca largha). It was...

  12. ATLAS Distributed Computing Automation

    CERN Document Server

    Schovancova, J; The ATLAS collaboration; Borrego, C; Campana, S; Di Girolamo, A; Elmsheuser, J; Hejbal, J; Kouba, T; Legger, F; Magradze, E; Medrano Llamas, R; Negri, G; Rinaldi, L; Sciacca, G; Serfon, C; Van Der Ster, D C

    2012-01-01

    The ATLAS Experiment benefits from computing resources distributed worldwide at more than 100 WLCG sites. The ATLAS Grid sites provide over 100k CPU job slots, over 100 PB of storage space on disk or tape. Monitoring of status of such a complex infrastructure is essential. The ATLAS Grid infrastructure is monitored 24/7 by two teams of shifters distributed world-wide, by the ATLAS Distributed Computing experts, and by site administrators. In this paper we summarize automation efforts performed within the ATLAS Distributed Computing team in order to reduce manpower costs and improve the reliability of the system. Different aspects of the automation process are described: from the ATLAS Grid site topology provided by the ATLAS Grid Information System, via automatic site testing by the HammerCloud, to automatic exclusion from production or analysis activities.

  13. Navigating Distributed Services

    DEFF Research Database (Denmark)

    Beute, Berco

    2002-01-01

    , to a situation where they are distributedacross the Internet. The second trend is the shift from a virtual environment that solelyconsists of distributed documents to a virtual environment that consists of bothdistributed documents and distributed services. The third and final trend is theincreasing diversity...... of devices used to access information on the Internet.The focal point of the thesis is an initial exploration of the effects of the trends onusers as they navigate the virtual environment of distributed documents and services.To begin the thesis uses scenarios as a heuristic device to identify and analyse...... themain effects of the trends. This is followed by an exploration of theory of navigationInformation Spaces, which is in turn followed by an overview of theories, and the stateof the art in navigating distributed services. These explorations of both theory andpractice resulted in a large number of topics...

  14. Projected Elliptical Distributions

    Institute of Scientific and Technical Information of China (English)

    Winfried Stute; Uwe Werner

    2005-01-01

    We introduce a new parametrization of elliptically contoured densities and study the associated family of projected (circular) distributions. In particular we investigate the trigonometric moments and some convolution properties.

  15. Ribbon Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) and reported breeding areas of ribbon seals (Histriophoca fasciata). It...

  16. Ringed Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) of the five subspecies of ringed seals (Phoca hispida). It was produced...

  17. DOLIB: Distributed Object Library

    Energy Technology Data Exchange (ETDEWEB)

    D`Azevedo, E.F.; Romine, C.H.

    1994-10-01

    This report describes the use and implementation of DOLIB (Distributed Object Library), a library of routines that emulates global or virtual shared memory on Intel multiprocessor systems. Access to a distributed global array is through explicit calls to gather and scatter. Advantages of using DOLIB include: dynamic allocation and freeing of huge (gigabyte) distributed arrays, both C and FORTRAN callable interfaces, and the ability to mix shared-memory and message-passing programming models for ease of use and optimal performance. DOLIB is independent of language and compiler extensions and requires no special operating system support. DOLIB also supports automatic caching of read-only data for high performance. The virtual shared memory support provided in DOLIB is well suited for implementing Lagrangian particle tracking techniques. We have also used DOLIB to create DONIO (Distributed Object Network I/O Library), which obtains over a 10-fold improvement in disk I/O performance on the Intel Paragon.

  18. White Dwarf Mass Distribution

    CERN Document Server

    Kepler, S O; Romero, Alejandra Daniela; Ourique, Gustavo; Pelisoli, Ingrid

    2016-01-01

    We present the mass distribution for all S/N > 15 pure DA white dwarfs detected in the Sloan Digital Sky Survey up to Data Release 12, fitted with Koester models for ML2/alpha=0.8, and with Teff > 10 000 K, and for DBs with S/N >10, fitted with ML2/alpha=1.25, for Teff > 16 000 K. These mass distributions are for log g > 6.5 stars, i.e., excluding the Extremely Low Mass white dwarfs. We also present the mass distributions corrected by volume with the 1/Vmax approach, for stars brighter than g=19. Both distributions have a maximum at M=0.624 Msun but very distinct shapes. From the estimated z-distances, we deduce a disk scale height of 300 pc. We also present 10 probable halo white dwarfs, from their galactic U, V, W velocities.

  19. Quantum Key Distribution

    Science.gov (United States)

    Seshu, Ch.

    Quantum Key Distribution (QKD) uses Quantum Mechanics to guarantee secure communication. It enables two parties to produce a shared random bit string known only to them, which can be used as a key to encrypt and decrypt messages.

  20. AUTOMATED SOFTWARE DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    J.J. Strasheim

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Automated distribution of computer software via electronic means in large corporate networks is growing in popularity. The relative importance of personal computer software, in financial and logistical terms, is described and the developing need for automated software distribution explained. An actual comparitive example of alternative software distribution strategies is presented and discussed proving the viability of Electronic Software Distribution.

    AFRIKAANSE OPSOMMING: Geoutomatiseerde verspreiding van rekenaarprogrammatuur met behulp van elektroniese metodes in groot korporatiewe netwerke, is toenemend populer, Die relatiewe belangrikheid van persoonlike rekenaarprogrammatuur in finansiele en logistieke terme word bespreek en die groeiende behoefte na geoutomatiseerde programmatuurverspreiding verduidelik. 'n Werklike vergelykende voorbeeld van alternatiewe programmatuurverspreidingsstrategiee word aangebied en bespreek wat die lewensvatbaarheid van Elektroniese Programmatuurverspreiding bewys.

  1. A Survey of Distributed Data Aggregation Algorithms

    CERN Document Server

    Jesus, Paulo; Almeida, Paulo Sérgio

    2011-01-01

    Distributed data aggregation is an important task, allowing the decentralized determination of meaningful global properties, that can then be used to direct the execution of other applications. The resulting values result from the distributed computation of functions like COUNT, SUM and AVERAGE. Some application examples can found to determine the network size, total storage capacity, average load, majorities and many others. In the last decade, many different approaches have been proposed, with different trade-offs in terms of accuracy, reliability, message and time complexity. Due to the considerable amount and variety of aggregation algorithms, it can be difficult and time consuming to determine which techniques will be more appropriate to use in specific settings, justifying the existence of a survey to aid in this task. This work reviews the state of the art on distributed data aggregation algorithms, providing three main contributions. First, it formally defines the concept of aggregation, characterizin...

  2. The NATO III 5 MHz Distribution System

    Science.gov (United States)

    Vulcan, A.; Bloch, M.

    1981-01-01

    A high performance 5 MHz distribution system is described which has extremely low phase noise and jitter characteristics and provides multiple buffered outputs. The system is completely redundant with automatic switchover and is self-testing. Since the 5 MHz reference signals distributed by the NATO III distribution system are used for up-conversion and multiplicative functions, a high degree of phase stability and isolation between outputs is necessary. Unique circuit design and packaging concepts insure that the isolation between outputs is sufficient to quarantee a phase perturbation of less than 0.0016 deg when other outputs are open circuited, short circuited or terminated in 50 ohms. Circuit design techniques include high isolation cascode amplifiers. Negative feedback stabilizes system gain and minimizes circuit phase noise contributions. Balanced lines, in lieu of single ended coaxial transmission media, minimize pickup.

  3. Polygamy of distributed entanglement

    Science.gov (United States)

    Buscemi, Francesco; Gour, Gilad; Kim, Jeong San

    2009-07-01

    While quantum entanglement is known to be monogamous (i.e., shared entanglement is restricted in multipartite settings), here we show that distributed entanglement (or the potential for entanglement) is by nature polygamous. By establishing the concept of one-way unlocalizable entanglement (UE) and investigating its properties, we provide a polygamy inequality of distributed entanglement in tripartite quantum systems of arbitrary dimension. We also provide a polygamy inequality in multiqubit systems and several trade-offs between UE and other correlation measures.

  4. Agile & Distributed Project Management

    DEFF Research Database (Denmark)

    Pries-Heje, Jan; Pries-Heje, Lene

    2011-01-01

    Scrum has gained surprising momentum as an agile IS project management approach. An obvious question is why Scrum is so useful? To answer that question we carried out a longitudinal study of a distributed project using Scrum. We analyzed the data using coding and categorisation and three carefull...... and coordination mechanisms by allowing both local and global articulation of work in the project. That is why Scrum is especially useful for distributed IS project management and teamwork....

  5. Distributed computing in bioinformatics.

    Science.gov (United States)

    Jain, Eric

    2002-01-01

    This paper provides an overview of methods and current applications of distributed computing in bioinformatics. Distributed computing is a strategy of dividing a large workload among multiple computers to reduce processing time, or to make use of resources such as programs and databases that are not available on all computers. Participating computers may be connected either through a local high-speed network or through the Internet.

  6. Parton Distributions Working Group

    Energy Technology Data Exchange (ETDEWEB)

    de Barbaro, L.; Keller, S. A.; Kuhlmann, S.; Schellman, H.; Tung, W.-K.

    2000-07-20

    This report summarizes the activities of the Parton Distributions Working Group of the QCD and Weak Boson Physics workshop held in preparation for Run II at the Fermilab Tevatron. The main focus of this working group was to investigate the different issues associated with the development of quantitative tools to estimate parton distribution functions uncertainties. In the conclusion, the authors introduce a Manifesto that describes an optimal method for reporting data.

  7. Consistency in Distributed Systems

    OpenAIRE

    Kemme, Bettina; Ramalingam, Ganesan; Schiper, André; Shapiro, Marc; Vaswani, Kapil

    2013-01-01

    International audience; In distributed systems, there exists a fundamental trade-off between data consistency, availability, and the ability to tolerate failures. This trade-off has significant implications on the design of the entire distributed computing infrastructure such as storage systems, compilers and runtimes, application development frameworks and programming languages. Unfortunately, it also has significant, and poorly understood, implications for the designers and developers of en...

  8. Intelligent distributed computing

    CERN Document Server

    Thampi, Sabu

    2015-01-01

    This book contains a selection of refereed and revised papers of the Intelligent Distributed Computing Track originally presented at the third International Symposium on Intelligent Informatics (ISI-2014), September 24-27, 2014, Delhi, India.  The papers selected for this Track cover several Distributed Computing and related topics including Peer-to-Peer Networks, Cloud Computing, Mobile Clouds, Wireless Sensor Networks, and their applications.

  9. Agile & Distributed Project Management

    DEFF Research Database (Denmark)

    Pries-Heje, Jan; Pries-Heje, Lene

    2011-01-01

    Scrum has gained surprising momentum as an agile IS project management approach. An obvious question is why Scrum is so useful? To answer that question we carried out a longitudinal study of a distributed project using Scrum. We analyzed the data using coding and categorisation and three carefully...... and coordination mechanisms by allowing both local and global articulation of work in the project. That is why Scrum is especially useful for distributed IS project management and teamwork....

  10. Children's contributions to pediatric outpatient encounters.

    NARCIS (Netherlands)

    Dulmen, A.M. van

    1998-01-01

    Objective: Generally, increasing attention is being paid to the quality of doctor-patient communication. However, children's contributions have been, until now, primarily ignored in communication research, although there are indications that considering their views increases satisfaction and complia

  11. CONTRIBUTIONS TO THE FUNCTIONAL MORPHOLOGY OF ...

    African Journals Online (AJOL)

    vessel, the John D. Gilchrist, some has been contributed by the South African Museum and ... a wide variety of types mostly from living material available in Holland, starting with a detailed account of ...... Orthragoriscus mola L. Zool. Meded.

  12. Jakob Nielsen and His Contributions to Topology

    DEFF Research Database (Denmark)

    Hansen, Vagn Lundsgaard

    1999-01-01

    The Danish mathematician Jakob Nielsen won international recognition as one of the developers of combinatorial group theory and the topology of surfaces. This article describes the life and work of Jakob Nielsen with emphasis on his contributions to topology....

  13. Parallel Harmony Search Based Distributed Energy Resource Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Oguzhan [ORNL; Liu, Guodong [ORNL; Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)

    2015-01-01

    This paper presents a harmony search based parallel optimization algorithm to minimize voltage deviations in three phase unbalanced electrical distribution systems and to maximize active power outputs of distributed energy resources (DR). The main contribution is to reduce the adverse impacts on voltage profile during a day as photovoltaics (PVs) output or electrical vehicles (EVs) charging changes throughout a day. The IEEE 123- bus distribution test system is modified by adding DRs and EVs under different load profiles. The simulation results show that by using parallel computing techniques, heuristic methods may be used as an alternative optimization tool in electrical power distribution systems operation.

  14. Charge and longitudinal momentum distributions in transverse coordinate space

    CERN Document Server

    Mondal, Chandan; Dahiya, Harleen; Chakrabarti, Dipankar

    2016-01-01

    We investigate the charge distributions for the $u$ and $d$ quarks in transverse coordinate space in a light-front quark-diquark model for the nucleons using the overlaps of the wave functions constructed from the soft-wall AdS/QCD prediction. We have also obtained the charge distributions for proton and neutron in transverse coordinate space and compared it with the distributions obtained in impact-parameter space. Further, we study the longitudinal momentum distributions using the wave functions in the transverse coordinate space. We have also shown the explicit fermionic and bosonic contributions for different struck $u$ and $d$ quarks.

  15. What contributes to depression in Parkinson's disease?

    OpenAIRE

    Schrag, A.; M. Jahanshahi; Quinn, N P

    2001-01-01

    Background: Depression is a common problem in patients with Parkinson's disease, but its mechanism is poorly understood. It is thought that neurochemical changes contribute to its occurrence, but it is unclear why some patients develop depression and others do not. Using a community-based sample of patients with Parkinson's disease, we investigated the contributions of impairment, disability and handicap to depression in Parkinson's disease. Methods: Ninety-seven patients seen in a popula...

  16. How sonochemistry contributes to green chemistry?

    Science.gov (United States)

    Chatel, Gregory

    2017-03-15

    Based on the analyses of papers from the literature, and especially those published in Ultrasonics Sonochemistry journal, the contribution of sonochemistry to green chemistry area has been discussed here. Important reminders and insights on the good practices and considerations have been made to understand and demonstrate how sonochemistry can continue to efficiently contribute to green chemistry area in the further studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Application of flower pollination algorithm for optimal placement and sizing of distributed generation in Distribution systems

    Directory of Open Access Journals (Sweden)

    P. Dinakara Prasad Reddy

    2016-05-01

    Full Text Available Distributed generator (DG resources are small, self contained electric generating plants that can provide power to homes, businesses or industrial facilities in distribution feeders. By optimal placement of DG we can reduce power loss and improve the voltage profile. However, the values of DGs are largely dependent on their types, sizes and locations as they were installed in distribution feeders. The main contribution of the paper is to find the optimal locations of DG units and sizes. Index vector method is used for optimal DG locations. In this paper new optimization algorithm i.e. flower pollination algorithm is proposed to determine the optimal DG size. This paper uses three different types of DG units for compensation. The proposed methods have been tested on 15-bus, 34-bus, and 69-bus radial distribution systems. MATLAB, version 8.3 software is used for simulation.

  18. Moment Distributions of Phase Type

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    -type distributions. We construct representations for moment distributions based on a general matrix-exponential distribution which turns out to be a generalization of the moment distributions based on exponential distributions. For moment distributions based on phase{type distributions we find an appropriate...... alternative representation in terms of sub{intensity matrices. Finally we are able to nd explicit expressions for both the Lorenz curve and the Gini index....

  19. Distributed Tracking in Distributed Sensor Networks

    Science.gov (United States)

    1988-05-26

    9.199 19252.332 109.909 S GoalStats (un, us, vn. we) :1779.225 -2511.597 -7.426 55.158 U R 4= Type NIlL nods (weight 1.999) : Rainuth and Azinuth Rate 1...9.168 9.39 E Typo NIlL node (weight 1.999) 1Sound Pressure and Rate :19175.527 295.949 S FO. 14 170 IN 190 291 216 2M 236 245 258 I IM Figure 6-5...San Diego, California 92121 (619) 587-1121 I II Distributed Sensor Program U Final ReportI by: I- Jack K. Wolf Andrew J. Viterbi -- Greg P. Heinzinger

  20. Distribution System Pricing with Distributed Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hledik, Ryan [The Brattle Group, Cambridge, MA (United States); Lazar, Jim [The Regulatory Assistance Project, Montpelier, VT (United States); Schwartz, Lisa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-08-16

    Technological changes in the electric utility industry bring tremendous opportunities and significant challenges. Customers are installing clean sources of on-site generation such as rooftop solar photovoltaic (PV) systems. At the same time, smart appliances and control systems that can communicate with the grid are entering the retail market. Among the opportunities these changes create are a cleaner and more diverse power system, the ability to improve system reliability and system resilience, and the potential for lower total costs. Challenges include integrating these new resources in a way that maintains system reliability, provides an equitable sharing of system costs, and avoids unbalanced impacts on different groups of customers, including those who install distributed energy resources (DERs) and low-income households who may be the least able to afford the transition.